JoVE Visualize What is visualize?
Stop Reading. Start Watching.
Advanced Search
Stop Reading. Start Watching.
Regular Search
Find video protocols related to scientific articles indexed in Pubmed.
Graphitic carbon nitride based nanocomposites: a review.
Nanoscale
PUBLISHED: 11-20-2014
Show Abstract
Hide Abstract
Graphitic carbon nitride (g-C3N4), as an intriguing earth-abundant visible light photocatalyst, possesses a unique two-dimensional structure, excellent chemical stability and tunable electronic structure. Pure g-C3N4 suffers from rapid recombination of photo-generated electron-hole pairs resulting in low photocatalytic activity. Because of the unique electronic structure, the g-C3N4 could act as an eminent candidate for coupling with various functional materials to enhance the performance. According to the discrepancies in the photocatalytic mechanism and process, six primary systems of g-C3N4-based nanocomposites can be classified and summarized: namely, the g-C3N4 based metal-free heterojunction, the g-C3N4/single metal oxide (metal sulfide) heterojunction, g-C3N4/composite oxide, the g-C3N4/halide heterojunction, g-C3N4/noble metal heterostructures, and the g-C3N4 based complex system. Apart from the depiction of the fabrication methods, heterojunction structure and multifunctional application of the g-C3N4-based nanocomposites, we emphasize and elaborate on the underlying mechanisms in the photocatalytic activity enhancement of g-C3N4-based nanocomposites. The unique functions of the p-n junction (semiconductor/semiconductor heterostructures), the Schottky junction (metal/semiconductor heterostructures), the surface plasmon resonance (SPR) effect, photosensitization, superconductivity, etc. are utilized in the photocatalytic processes. Furthermore, the enhanced performance of g-C3N4-based nanocomposites has been widely employed in environmental and energetic applications such as photocatalytic degradation of pollutants, photocatalytic hydrogen generation, carbon dioxide reduction, disinfection, and supercapacitors. This critical review ends with a summary and some perspectives on the challenges and new directions in exploring g-C3N4-based advanced nanomaterials.
Related JoVE Video
Magnetically recoverable Ni/C catalysts with hierarchical structure and high-stability for selective hydrogenation of nitroarenes.
Phys Chem Chem Phys
PUBLISHED: 11-20-2014
Show Abstract
Hide Abstract
Here we report that magnetic Ni/C catalysts with hierarchical structure can be fabricated from a mixture of nickel acetate, polyethylene glycol-200 and furfural by a one-step hydrothermal method, followed by calcination. It has been found that the calcination temperature is the key factor affecting the structure, morphology and the catalytic performance of the Ni/C catalysts. Of the as-made catalysts, the Ni/C sample calcined at 300 °C features small-size metallic Ni particles with high dispersion in the carbon matrix and a unique hierarchical structure, and has the highest rate of conversion of o-chloronitrobenzene with high selectivity to o-chloroanilines. The concerned Ni/C catalysts are magnetic due to the presence of metallic Ni particles, which makes their recovery easy after the reaction by an external magnetic field. The recovered Ni/C catalysts can be recycled at least ten times without obvious loss both in Ni loading and the catalytic performance. This kind of catalyst is also active for the selective hydrogenation of other nitroarenes to the corresponding anilines.
Related JoVE Video
Modified secondary lithium metal batteries with the polyaniline-carbon nanotube composite buffer layer.
Chem. Commun. (Camb.)
PUBLISHED: 11-20-2014
Show Abstract
Hide Abstract
A modified secondary lithium metal battery inserted with a polyaniline-carbon nanotube nanoporous composite buffer layer was fabricated. This unique and simple design of battery has the great potential to decrease the safety risk of the secondary Li metal battery in cycles of recharging processes and improve its cycle life in the future.
Related JoVE Video
Tuning spin polarization and spin transport of zigzag graphene nanoribbons by line defects.
Phys Chem Chem Phys
PUBLISHED: 11-20-2014
Show Abstract
Hide Abstract
From first-principles methods, the spin-dependent electronic properties of zigzag-edged graphene nanoribbons (ZGNRs) with a line defect (558-defect) are investigated systematically and compared to those of the pristine ZGNR. Results show that the line defect possesses an obvious tuning effect on the spin-polarization of the edge carbon atoms of the defective ZGNRs, and the spin-polarization and spin-transport are sensitive to the position of line defects. The defective ZGNRs can realize a transition from antiferromagnetism (AFM) to ferrimagnetism and ferromagnetism (FM) via changing the position of line defects from the center to the zigzag edge of ZGNRs. More importantly, when the line defect is located at the one edge, the defective ZGNRs exhibit the long-range magnetic ordering at edges with a high Curie temperature up to 276 K, and the defective ZGNR system can generate a high-performance spin-filter effect in the large bias range, 0.0-0.5 V. Such a sensitive modulation for the spin-polarization and spin-transport holds great promise for applications of the graphene-based systems in nano-scale spintronic devices.
Related JoVE Video
Thymic hyperplasia following chemotherapy in adults with lymphoma: (18)F-FDG PET/CT findings and correlation with the T cell repopulation.
Leuk. Lymphoma
PUBLISHED: 11-20-2014
Show Abstract
Hide Abstract
Abstract Thymic hyperplasia (TH) after chemotherapy is an infrequent phenomenon in adults. This study analyzed the incidence and metabolic activity of TH on (18)F fluorodeoxyglucose ((18)F FDG) positron emission tomography / computed tomography (PET/CT) in this population. By reviewing 471 PET/CT recordings of 211 adults with lymphoma, increased FDG uptake within an enlarged thymus regarded as TH was observed in 27 patients aged 18-53 years. FDG uptake in hyperplasic thymus was mild and diffuse, with a maximum standard uptake value (SUVmax) of 2.6±0.9. Its intensity varied with different occurring times following chemotherapy. In addition, by comparing the recovery of T cell subsets in patients with TH (n=20) and without TH (n=28), no impact of the presence of TH was found on the repopulation of total CD4(+) and CD8(+) T cells within the first year after treatment. These data may be helpful to avoid misinterpretation of increased thymic uptake in adults.
Related JoVE Video
Synthesis, in Vitro Covalent Binding Evaluation, and Metabolism of (14)C-Labeled Inhibitors of 11?-HSD1.
ACS Med Chem Lett
PUBLISHED: 11-13-2014
Show Abstract
Hide Abstract
In this letter, we reported the design and synthesis of three potent, selective, and orally bioavailable 11?-HSD1 inhibitors labeled with (14)C: AMG 456 (1), AM-6949 (2), and AM-7715 (3). We evaluated the covalent protein binding of the labeled inhibitors in human liver microsomes in vitro and assessed their potential bioactivation risk in humans. We then studied the in vitro mechanism of 2 in human hepatocytes and the formation of reactive intermediates. Our study results suggest that 1 and 3 have low potential for metabolic bioactivation in humans, while 2 has relatively high risk.
Related JoVE Video
[Observation study on aerosol optical properties and radiative forcing using the ground-based and satellite remote sensing at background station during the regional pollution episodes].
Huan Jing Ke Xue
PUBLISHED: 09-24-2014
Show Abstract
Hide Abstract
The significant effect of anthropogenic pollutants transportation on the physical and optical properties of regional background atmospheric aerosol was studied by using ground-based and satellite remote sensing data obtained at the atmospheric background station (Shangdianzi, Beijing) of North China during October 1 to 15 in 2011. The aerosol mass concentration and reactive gases concentration increased obviously during periods of October 4-5, October 7-9, and October 11-12. Comparing with the background period of October 1-3, volume concentration increased by a factor of 3-6 for reactive gases such as NO(x), and CO, and a factor of 10-20 for SO2. Mass concentration of PM2.5 was about 200 microg x m(-3) on October 9. During haze period, the AOD at 500 nm varied between 0.60 to 1.00. The single scattering albedo (SSA) was lower than 0.88. And the black carbon concentration increased 4-8 times, which suggested the aerosol absorption was very strong during this pollution episode. The absorption of aerosol particles could cause 100-400 W x m(-2) increase of atmospheric radiation. The surface radiation decreased by about 100-300 W x m(-2) due to the aerosol scattering and absorption. This could cause higher stability of atmosphere, which will significantly affect the cloud and precipitation, and thus the regional weather and climate.
Related JoVE Video
Different effects of LDH-A inhibition by oxamate in non-small cell lung cancer cells.
Oncotarget
PUBLISHED: 09-23-2014
Show Abstract
Hide Abstract
Higher rate of glycolysis has been long observed in cancer cells, as a vital enzyme in glycolysis, lactate dehydrogenase A (LDH-A) has been shown with great potential as an anti-cancer target. Accumulating evidence indicates that inhibition of LDH-A induces apoptosis mediated by oxidative stress in cancer cells. To date, it's still unclear that whether autophagy can be induced by LDH-A inhibition. Here, we investigated the effects of oxamate, one classic inhibitor of LDH-A in non-small cell lung cancer (NSCLC) cells as well as normal lung epithelial cells. The results showed that oxamate significantly suppressed the proliferation of NSCLC cells, while it exerted a much lower toxicity in normal cells. As previous studies reported, LDH-A inhibition resulted in ATP reduction and ROS (reactive oxygen species) burst in cancer cells, which lead to apoptosis and G2/M arrest in H1395 cells. However, when being exposed to oxamate, A549 cells underwent autophagy as a protective mechanism against apoptosis. Furthermore, we found evidence that LDH-A inhibition induced G0/G1 arrest dependent on the activation of GSK-3? in A549 cells. Taken together, our results provide useful clues for targeting LDH-A in NSCLC treatment and shed light on the discovery of molecular predictors for the sensitivity of LDH-A inhibitors.
Related JoVE Video
Stable 4 V-class bicontinuous cathodes by hierarchically porous carbon coating on Li3V2(PO4)3 nanospheres.
Nanoscale
PUBLISHED: 09-20-2014
Show Abstract
Hide Abstract
A high performance, durable cathode material for lithium ion batteries is achieved by incorporating ?50 nm Li3V2(PO4)3/C core-shell nanospheres into a porous carbon framework. The Li3V2(PO4)3/C nanocomposite delivers an initial discharge capacity of 130 mA h g(-1), approaching its theoretical limit (133 mA h g(-1)). At a high current rate (10 C), the nanocomposite displays an impressive long cycle life and remarkable capacity retention (90% after 1200 cycles). Notably, the Coulombic efficiency is above 99% during the course of cycling. The remarkable power capability and cycle stability derived from our simple and scalable synthesis suggests that this 4 V-class material could be one of the most promising candidates for future batteries.
Related JoVE Video
Association between polymorphism of GLI1 gene SNP rs2228226 and chronic lymphocytic leukemia in Chinese population.
Med. Oncol.
PUBLISHED: 09-14-2014
Show Abstract
Hide Abstract
A non-synonymous single-nucleotide polymorphism (SNP) (rs2228226C>G), in exon 12 of glioma-associated oncogene homolog 1 (GLI1) (Q1100E), encodes a change from glutamine to glutamic acid (Q1100E). The variant GLI1 protein exhibited reduced transactivation function in vivo, decreasing the ability of activating hedgehog signal, which has been proposed as an unfavorable prognostic marker in chronic lymphocytic leukemia (CLL). The GLI1 Q1100E (NCBI SNP ID: rs2228226) genotypes in 155 CLL patients were detected by direct sequencing. The difference between frequencies of GLI1 Q1100E genotype among CLL patients and controls was statistically significant (p < 0.001). Logistic regression analysis revealed that in comparison with G/G, GLI1 SNP1100 C/C genotype was associated with a significantly increased risk of CLL (OR 3.787, 95 % CI 1.814-7.907, p < 0.001). Compared with the SNP1100 C/G genotype, C/C genotype significantly increased the risk of CLL (OR 3.860, 95 % CI 1.827-8.153, p < 0.001). In addition, combining C/G with G/G, C/C genotype also significantly increased the risk of CLL (OR 3.820, 95 % CI 1.885-7.742, p < 0.001). The comparison between frequencies of C and G allele of GLI1 was also statistically significant (p = 0.004). In the entire cohort, SNP1100 genotypes were found in association with Binet stage (p = 0.045) and trisomy 12 (p = 0.036). By comparing C/C with G allele (C/G+G/G) genotype, there was a significant correlation with trisomy 12 (p = 0.013). This study demonstrated that GLI1 Q1100E polymorphism was closely associated with CLL. C/C genotype contributes to the risk of developing CLL and correlates with trisomy 12. Patients with trisomy 12 are susceptible group of CLL.
Related JoVE Video
Estimating radiation absorbed dose of individuals nearby 131I-treated hyperthyroid patients.
Health Phys
PUBLISHED: 09-11-2014
Show Abstract
Hide Abstract
The purpose of this study was to systematically provide a database for estimating radiation dose of individuals nearby (131)I-treated hyperthyroid patients. External dose rates were measured on 48 hyperthyroid patients using a survey meter in front of patients' thyroid glands. The initial measurement was recorded within 30 min post radioiodine administration at 0.3 m, 0.6 m, 1 m, and 2 m. Follow-up measurements were carried out up to 12 d post radioiodine administration. In addition, ambient dose rates of different locations such as wards, patients' washrooms, medical staffs' workplaces, and corridors were also measured. The Na131I treatment dose administered in this study ranged from 74-555 MBq. Significant positive correlation between dose rate at 1 m and the administered dose was found in this study. The normalized external dose rates at 0.3 m were 0.234 µSv h(-1) MBq(-1) at 0.5 h, 0.325 µSv h(-1) MBq(-1) at 4 h, 0.308 µSv h(-1) MBq(-1) at 6 h, 0.301 µSv h(-1) MBq(-1) at 24 h, 0.259 µSv h(-1) MBq(-1) at 48 h, 0.234 µSv h(-1) MBq(-1) at 72 h, 0.224 µSv h(-1) MBq(-1) at 96 h, 0.186 µSv h(-1) MBq(-1) at 120 h, and 0.158 µSv h(-1) MBq(-1) at 144 h, respectively. With these results, the authors estimated radioactive radiation dose for the public and medical staffs near (131)I-treated hyperthyroid patients. This study is beneficial for radiation safety decision-making.
Related JoVE Video
Acute downregulation of miR-155 at wound sites leads to a reduced fibrosis through attenuating inflammatory response.
Biochem. Biophys. Res. Commun.
PUBLISHED: 09-03-2014
Show Abstract
Hide Abstract
Fibrosis, tightly associated with wound healing, is a significant symptomatic clinical problem. Inflammatory response was reported to be one of the reasons. MiR-155 is relatively related with the development and requirement of inflammatory cells, so we thought reduce the expression of miR-155 in wound sites could improve the quality of healing through reduce inflammatory response. To test this hypothesis, locally antagonizing miR-155 by directly injecting antagomir to wound edge was used to reduce the expression of miR-155. We found wounds treated with miR-155 antagomir had an obvious defect in immune cells requirements, pro-inflammatory factors IL-1? and TNF-? reduced while anti-inflammatory factor IL-10 increased. With treatment of miR-155 antagomir, the expression of ?-smooth muscle actin (?-SMA), Col1 and Col3 at wound sites all reduced both from mRNA levels and protein expressions. Wounds injected with antagomir resulted in the structure improvement of collagen, the collagen fibers were more regularly arranged. Meanwhile the rate of healing did not change significantly. These results provide direct evidences that miR-155 play an important role in the pathogenesis of fibrosis and show that miR-155 antagomir has the potential therapy in prevention and reduction of skin fibrosis.
Related JoVE Video
Trap-state-dominated suppression of electron conduction in carbon nanotube thin-film transistors.
ACS Nano
PUBLISHED: 09-03-2014
Show Abstract
Hide Abstract
The often observed p-type conduction of single carbon nanotube field-effect transistors is usually attributed to the Schottky barriers at the metal contacts induced by the work function differences or by the doping effect of the oxygen adsorption when carbon nanotubes are exposed to air, which cause the asymmetry between electron and hole injections. However, for carbon nanotube thin-film transistors, our contrast experiments between oxygen doping and electrostatic doping demonstrate that the doping-generated transport barriers do not introduce any observable suppression of electron conduction, which is further evidenced by the perfect linear behavior of transfer characteristics with the channel length scaling. On the basis of the above observation, we conclude that the environmental adsorbates work by more than simply shifting the Fermi level of the CNTs; more importantly, these adsorbates cause a poor gate modulation efficiency of electron conduction due to the relatively large trap state density near the conduction band edge of the carbon nanotubes, for which we further propose quantitatively that the adsorbed oxygen-water redox couple is responsible.
Related JoVE Video
Microenvironmental pH-modified solid dispersions to enhance the dissolution and bioavailability of poorly water-soluble weakly basic GT0918, a developing anti-prostate cancer drug: Preparation, characterization and evaluation in vivo.
Int J Pharm
PUBLISHED: 08-27-2014
Show Abstract
Hide Abstract
The aim of the present work was to design a pH-modified solid dispersion (pHM-SD) that can improve the dissolution and bioavailability of poorly water-soluble weakly basic GT0918, a developing anti-prostate cancer drug. To select the appropriate acidifiers, a solubility test was carried out first. Solid dispersions (SDs) containing GT0918 and polyvinylpyrrolidone (PVP) were prepared using a solvent evaporation method and were characterized using dissolution studies in different media. The solid states of the SDs were investigated using scanning electron microscopy (SEM), powder X-ray diffraction (PXRD), differential scanning calorimetry (DSC) and Fourier transformed infrared spectroscopy (FTIR). The in vivo pharmacokinetics of the pHM-SDs tablets were also studied in beagle dogs compared to the conventional tablets. The optimized pHM-SD (GT0918/PVP/citric acid, 1:2:2 weight ratio) exhibited a significant improvement in the dissolution behavior compared to both the physical mixture and the binary SDs. Solid-state characterization revealed that the amorphous formation of GT0918 in the SDs and the strong H-bonding were only found in the pHM-SDs containing citric acid. Furthermore, the GT0918-loaded pHM-SD tablets showed a higher AUC and a lower tmax compared to the conventional tablets. Accordingly, the pHM-SD might be an efficient route for enhancing the dissolution and bioavailability of poorly water-soluble GT0918.
Related JoVE Video
A worldwide survey of genome sequence variation provides insight into the evolutionary history of the honeybee Apis mellifera.
Nat. Genet.
PUBLISHED: 08-24-2014
Show Abstract
Hide Abstract
The honeybee Apis mellifera has major ecological and economic importance. We analyze patterns of genetic variation at 8.3 million SNPs, identified by sequencing 140 honeybee genomes from a worldwide sample of 14 populations at a combined total depth of 634×. These data provide insight into the evolutionary history and genetic basis of local adaptation in this species. We find evidence that population sizes have fluctuated greatly, mirroring historical fluctuations in climate, although contemporary populations have high genetic diversity, indicating the absence of domestication bottlenecks. Levels of genetic variation are strongly shaped by natural selection and are highly correlated with patterns of gene expression and DNA methylation. We identify genomic signatures of local adaptation, which are enriched in genes expressed in workers and in immune system- and sperm motility-related genes that might underlie geographic variation in reproduction, dispersal and disease resistance. This study provides a framework for future investigations into responses to pathogens and climate change in honeybees.
Related JoVE Video
Reproducibility of T2 * mapping in the human cerebral cortex in vivo at 7 tesla MRI.
J Magn Reson Imaging
PUBLISHED: 08-19-2014
Show Abstract
Hide Abstract
To assess the test-retest reproducibility of cortical mapping of T2 * relaxation rates at 7 Tesla (T) MRI. T2 * maps have been used for studying cortical myelo-architecture patterns in vivo and for characterizing conditions associated with changes in iron and/or myelin concentration.
Related JoVE Video
Immobilization of polymeric g-C3N4 on structured ceramic foam for efficient visible light photocatalytic air purification with real indoor illumination.
Environ. Sci. Technol.
PUBLISHED: 08-14-2014
Show Abstract
Hide Abstract
The immobilization of a photocatalyst on a proper support is pivotal for practical environmental applications. In this work, graphitic carbon nitride (g-C3N4) as a rising visible light photocatalyst was first immobilized on structured Al2O3 ceramic foam by a novel in situ approach. Immobilized g-C3N4 was applied for photocatalytic removal of 600 ppb level NO in air under real indoor illumination of an energy-saving lamp. The photocatalytic activity of immobilized g-C3N4 was gradually improved as the pyrolysis temperature was increased from 450 to 600 °C. The optimized conditions for g-C3N4 immobilization on Al2O3 supports can be achieved at 600 °C for 2 h. The NO removal ratio could reach up to 77.1%, exceeding that of other types of well-known immobilized photocatalysts. Immobilized g-C3N4 was stable in activity and can be used repeatedly without deactivation. The immobilization of g-C3N4 on Al2O3 ceramic foam was found to be firm enough to overwhelm the continuous air flowing, which can be ascribed to the special chemical interaction between g-C3N4 and Al2O3. On the basis of the 5,5'-dimethyl-1-pirroline-N-oxide electron spin resonance (DMPO ESR) spin trapping and reaction intermediate monitoring, the active species produced from g-C3N4 under illumination were confirmed and the reaction mechanism of photocatalytic NO oxidation by g-C3N4 was revealed. The present work could provide new perspectives for promoting large-scale environmental applications of supported photocatalysts.
Related JoVE Video
The Study of External Dose Rate and Retained Body Activity of Patients Receiving 131I Therapy for Differentiated Thyroid Carcinoma.
Int J Environ Res Public Health
PUBLISHED: 08-13-2014
Show Abstract
Hide Abstract
Radiation safety is an integral part of targeted radionuclide therapy. The aim of this work was to study the external dose rate and retained body activity as functions of time in differentiated thyroid carcinoma patients receiving 131I therapy. Seventy patients were stratified into two groups: the ablation group (A) and the follow-up group (FU). The patients' external dose rate was measured, and simultaneously, their retained body radiation activity was monitored at various time points. The equations of the external dose rate and the retained body activity, described as a function of hours post administration, were fitted. Additionally, the release time for patients was calculated. The reduction in activity in the group receiving a second or subsequent treatment was more rapid than the group receiving only the initial treatment. Most important, an expeditious method was established to indirectly evaluate the retained body activity of patients by measuring the external dose rate with a portable radiation survey meter. By this method, the calculated external dose rate limits are 19.2, 8.85, 5.08 and 2.32 ?Sv·h-1 at 1, 1.5, 2 and 3 m, respectively, according to a patient's released threshold level of retained body activity <400 MBq. This study is beneficial for radiation safety decision-making.
Related JoVE Video
Nanotube liquid crystal elastomers: photomechanical response and flexible energy conversion of layered polymer composites.
Nanotechnology
PUBLISHED: 08-12-2014
Show Abstract
Hide Abstract
Elastomeric composites based on nanotube liquid crystals (LCs) that preserve the internal orientation of nanotubes could lead to anisotropic physical properties and flexible energy conversion. Using a simple vacuum filtration technique of fabricating nanotube LC films and utilizing a transfer process to poly (dimethyl) siloxane wherein the LC arrangement is preserved, here we demonstrate unique and reversible photomechanical response of this layered composite to excitation by near infra-red (NIR) light at ultra-low nanotube mass fractions. On excitation by NIR photons, with application of small or large pre-strains, significant expansion or contraction of the sample occurs, respectively, that is continuously reversible and three orders of magnitude larger than in pristine polymer. Schlieren textures were noted in these LC composites confirming long range macroscopic nematic order of nanotubes within the composites. Order parameters of LC films ranged from S(optical) = 0.51-0.58 from dichroic measurements. Film concentrations, elastic modulus and photomechanical stress were all seen to be related to the nematic order parameter. For the same nanotube concentration, the photomechanical stress was almost three times larger for the self-assembled LC nanotube actuator compared to actuator based on randomly oriented carbon nanotubes. Investigation into the kinetics of photomechanical actuation showed variation in stretching exponent ? with pre-strains, concentration and orientation of nanotubes. Maximum photomechanical stress of ? 0.5 MPa W(-1) and energy conversion of ? 0.0045% was achieved for these layered composites. The combination of properties, namely, optical anisotropy, reversible mechanical response to NIR excitation and flexible energy conversion all in one system accompanied with low cost makes nanotube LC elastomers important for soft photochromic actuation, energy conversion and photo-origami applications.
Related JoVE Video
Extremely low-frequency electromagnetic fields cause G1 phase arrest through the activation of the ATM-Chk2-p21 pathway.
PLoS ONE
PUBLISHED: 08-11-2014
Show Abstract
Hide Abstract
In daily life, humans are exposed to the extremely low-frequency electromagnetic fields (ELF-EMFs) generated by electric appliances, and public concern is increasing regarding the biological effects of such exposure. Numerous studies have yielded inconsistent results regarding the biological effects of ELF-EMF exposure. Here we show that ELF-EMFs activate the ATM-Chk2-p21 pathway in HaCaT cells, inhibiting cell proliferation. To present well-founded results, we comprehensively evaluated the biological effects of ELF-EMFs at the transcriptional, protein, and cellular levels. Human HaCaT cells from an immortalized epidermal keratinocyte cell line were exposed to a 1.5 mT, 60 Hz ELF-EMF for 144 h. The ELF-EMF could cause G1 arrest and decrease colony formation. Protein expression experiments revealed that ELF-EMFs induced the activation of the ATM/Chk2 signaling cascades. In addition, the p21 protein, a regulator of cell cycle progression at G1 and G2/M, exhibited a higher level of expression in exposed HaCaT cells compared with the expression of sham-exposed cells. The ELF-EMF-induced G1 arrest was diminished when the CHK2 gene expression (which encodes checkpoint kinase 2; Chk2) was suppressed by specific small interfering RNA (siRNA). These findings indicate that ELF-EMFs activate the ATM-Chk2-p21 pathway in HaCaT cells, resulting in cell cycle arrest at the G1 phase. Based on the precise control of the ELF-EMF exposure and rigorous sham-exposure experiments, all transcriptional, protein, and cellular level experiments consistently supported the conclusion. This is the first study to confirm that a specific pathway is triggered by ELF-EMF exposure.
Related JoVE Video
miR-26a and miR-214 down-regulate expression of the PTEN gene in chronic lymphocytic leukemia, but not PTEN mutation or promoter methylation.
Oncotarget
PUBLISHED: 07-28-2014
Show Abstract
Hide Abstract
We previous found the expression level of PTEN was low in the chronic lymphocytic leukemia (CLL) patients. To assess the pathogenic contribution of the low expression of PTEN, we determined PTEN-regulating miRNA interference, PTEN promoter methylation and PTEN gene mutation condition in CLL. One hundred and fifty-four previously untreated CLL patients and 200 cases of healthy controls were sequenced in exons 5-9 of PTEN. None of single nucleotide polymorphism site or mutation was detected in the coding sequences of those exons. Methylation of PTEN promoter was found in one (1.33%) of the 75 patients with CLL, but none of the 25 age-matched control subjects. We found that PTEN was a potential target of miR-26a and miR-214, which had been confirmed following dual-luciferase reporter assays, reverse transcription polymerase chain reaction and Western blotting. High expression of miR-26a was associated with advanced Binet stage (P=0.012), p53 aberrations (P=0.014) and inferior time to first treatment (P=0.038), and high expression of miR-214 was only associated with p53 aberrations (P=0.041). Inhibition of miR-26a or miR-214 could induce more apoptosis in primary cultured CLL cells. These findings support miR-26a and miR-214 down-regulate expression of PTEN in CLL, but not PTEN mutation or promoter methylation.
Related JoVE Video
Storage of Gold Nanoclusters in Muscle Leads to their Biphasic in Vivo Clearance.
Small
PUBLISHED: 07-25-2014
Show Abstract
Hide Abstract
Ultrasmall gold nanoclusters (Au NCs) show great potential in biomedical applications. Long-term biodistribution, retention, toxicity, and pharmacokinetics profiles are pre-requisites in their potential clinical applications. Here, the biodistribution, clearance, and toxicity of one widely used Au NC species-glutathione-protected Au NCs or GSH-Au NCs-are systematically investigated over a relatively long period of 90 days in mice. Most of the Au NCs are cleared at 30 days post injection (p.i.) with a major accumulation in liver and kidney. However, it is surprising that an abnormal increase of the Au amount in the heart, liver, spleen, lung, and testis is observed at 60 and 90 days p.i., indicating that the injected Au NCs form a V-shaped time-dependent distribution profile in various organs. Further investigations reveal that Au NCs are steadily accumulating in the muscle in the first 30 days p.i., and the as-stored Au NCs gradually release into the blood in 30-90 days p.i., which induces a re-distribution and re-accumulation of Au NCs in all blood-rich organs. Further hematology and biochemistry studies show that the re-accumulation of Au NCs still causes some liver toxicity at 30 days p.i. The muscle storage and subsequent release may give rise to the potential accumulation and toxicity risk of functional nanomaterials over long periods of time.
Related JoVE Video
Generation of CRISPR/Cas9-mediated gene-targeted pigs via somatic cell nuclear transfer.
Cell. Mol. Life Sci.
PUBLISHED: 07-20-2014
Show Abstract
Hide Abstract
The domestic pig has been widely used as an important large animal model. Precise and efficient genetic modification in pig provides a great promise in biomedical research. Recently, clustered regularly interspaced short palindromic repeat (CRISPR)/CRISPR-associated (Cas) system has been successfully used to produce many gene-targeted animals. However, these animals have been generated by co-injection of Cas9 mRNA and single-guide RNA (sgRNA) into one-cell stage embryos, which mostly resulted in mosaicism of the modification. One or two rounds of further breeding should be performed to obtain homozygotes with identical genotype and phenotype. To address this issue, gene-targeted somatic cells can be used as donor for somatic cell nuclear transfer (SCNT) to produce gene-targeted animals with single and identical mutations. In this study, we applied Cas9/sgRNAs to effectively direct gene editing in porcine fetal fibroblasts and then mutant cell colonies were used as donor to generate homozygous gene-targeted pigs through single round of SCNT. As a result, we successfully obtained 15 tyrosinase (TYR) biallelic mutant pigs and 20 PARK2 and PINK1 double-gene knockout (KO) pigs. They were all homozygous and no off-target mutagenesis was detected by comprehensive analysis. TYR (-/-) pigs showed typical albinism and the expression of parkin and PINK1 were depleted in PARK2 (-/-)/PINK1 (-/-) pigs. The results demonstrated that single- or double-gene targeted pigs can be effectively achieved by using the CRISPR/Cas9 system combined with SCNT without mosaic mutation and detectable off-target effects. This gene-editing system provides an efficient, rapid, and less costly manner to generate genetically modified pigs or other large animals.
Related JoVE Video
Quantitative oxygen extraction fraction from 7-Tesla MRI phase: reproducibility and application in multiple sclerosis.
J. Cereb. Blood Flow Metab.
PUBLISHED: 07-14-2014
Show Abstract
Hide Abstract
Quantitative oxygen extraction fraction (OEF) in cortical veins was studied in patients with multiple sclerosis (MS) and healthy subjects via magnetic resonance imaging (MRI) phase images at 7 Tesla (7 T). Flow-compensated, three-dimensional gradient-echo scans were acquired for absolute OEF quantification in 23 patients with MS and 14 age-matched controls. In patients, we collected T2*-weighted images for characterization of white matter, deep gray matter, and cortical lesions, and also assessed cognitive function. Variability of OEF across readers and scan sessions was evaluated in a subset of volunteers. OEF was averaged from 2 to 3 pial veins in the sensorimotor, parietal, and prefrontal cortical regions for each subject (total of ~10 vessels). We observed good reproducibility of mean OEF, with intraobserver coefficient of variation (COV)=2.1%, interobserver COV=5.2%, and scan-rescan COV=5.9%. Patients exhibited a 3.4% reduction in cortical OEF relative to controls (P=0.0025), which was not different across brain regions. Although oxygenation did not relate with measures of structural tissue damage, mean OEF correlated with a global measure of information processing speed. These findings suggest that cortical OEF from 7-T MRI phase is a reproducible metabolic biomarker that may be sensitive to different pathologic processes than structural MRI in patients with MS.Journal of Cerebral Blood Flow & Metabolism advance online publication, 29 October 2014; doi:10.1038/jcbfm.2014.187.
Related JoVE Video
Changes in the Glucocorticoid Receptor and Ca(2+)/Calreticulin-Dependent Signalling Pathway in the Medial Prefrontal Cortex of Rats with Post-traumatic Stress Disorder.
J. Mol. Neurosci.
PUBLISHED: 07-10-2014
Show Abstract
Hide Abstract
The glucocorticoid receptor (GR), calreticulin (CRT) and protein kinase C (PKC) have all been implicated in the Ca(2+)-dependent signalling pathway, which plays an important role in the plasticity of the central nervous system, learning and memory. The medial prefrontal cortex (mPFC) is known to be involved in mechanisms of learning and memory. In the present study, single prolonged stress (SPS) was used as an animal model of post-traumatic stress disorder (PTSD). The Morris water maze test was used to detect rats' ability for spatial memory and learning. A fluorescence spectrophotometer was used to measure the concentration of intracellular Ca(2+) in mPFC. Immunohistochemistry, immunofluorescence, western blot and reverse transcription polymerase chain reaction were used to explore changes in GR, CRT and PKC in mPFC of SPS rats. The concentration of Ca(2+) in mPFC was increased in the SPS rats. We found increased intensity of GR and CRT immunoreactivity and increased messenger RNA (mRNA) levels of GR, CRT and PKC in mPFC of the SPS groups, although the degree and time of increase was different among them. The protein levels of cytoplasmic GR, cytoplasmic CRT and cytoplasmic pPKC increased in mPFC of the SPS groups, whereas the protein level of nuclear GR decreased in comparison with the control group. As a conclusion, changed CRT and GR/PKC were involved in the mechanism of SPS-induced dysfunctional mPFC.
Related JoVE Video
A combined experimental and computational study of Vam3, a derivative of resveratrol, and Syk interaction.
Int J Mol Sci
PUBLISHED: 07-08-2014
Show Abstract
Hide Abstract
Spleen tyrosine kinase (Syk) plays an indispensable role through preliminary extracellular antigen-induced crosslinking of Fc receptor (FcR) in the pathogenesis of autoimmune disorders, such as rheumatoid arthritis. In this study, we identify Vam3, a dimeric derivative of resveratrol isolated from grapes, as an ATP-competitive inhibitor of Syk with an IC50 of 62.95 nM in an in vitro kinase assay. Moreover, docking and molecular dynamics simulation approaches were performed to get more detailed information about the binding mode of Vam3 and Syk. The results show that 11b-OH on ring-C and 4b-OH on ring-D could form two hydrogen bonds with Glu449 and Phe382 of Syk, respectively. In addition, arene-cation interaction between ring-D of Vam3 and Lys402 of Syk was also observed. These results indicate that ring-C and D play an essential role in Vam3-Syk interaction. Our studies may be helpful in the structural optimization of Vam3, and also aid the design of novel Syk inhibitors in the future.
Related JoVE Video
Facile synthesis of organic-inorganic layered nanojunctions of g-C3N4/(BiO)2CO3 as efficient visible light photocatalyst.
Dalton Trans
PUBLISHED: 07-01-2014
Show Abstract
Hide Abstract
Novel g-C3N4/(BiO)2CO3 organic-inorganic nanojunctioned photocatalysts were synthesized by in situ depositing (BiO)2CO3 nanoflakes onto the surface of g-C3N4 nanosheets through a one-pot efficient capture of atmospheric CO2 method at room temperature. The as-synthesized samples were characterized by X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), UV-vis diffuse reflectance spectroscopy (DRS), N2 adsorption-desorption analysis and electron spin resonance (ESR). The photocatalytic activity of as-synthesized samples was evaluated by degrading Rhodamine B (RhB) and phenol in aqueous solution under visible-light irradiation. The g-C3N4/(BiO)2CO3 nanojunctions showed much higher visible-light photocatalytic activity than those of pure g-C3N4 and (BiO)2CO3 for the degradation of RhB and phenol. The enhanced photocatalytic activity can be mainly ascribed to the well-matched band structures, dye photosensitization and efficient crystal facets coupling interaction between g-C3N4 {002} and (BiO)2CO3 {002}. The ?O2(-) radicals were identified as the main active species. Furthermore, the pure (BiO)2CO3 with highly exposed {002} crystal facets also exhibited excellent visible-light photoactivity for the degradation of RhB, which can be originated from the indirect dye photosensitization. The present work could provide a new strategy for the efficient utilization of atmospheric CO2 in green synthetic chemistry.
Related JoVE Video
RAG1/2 knockout pigs with severe combined immunodeficiency.
J. Immunol.
PUBLISHED: 06-27-2014
Show Abstract
Hide Abstract
Pigs share many physiological, biochemical, and anatomical similarities with humans and have emerged as valuable large animal models for biomedical research. Considering the advantages in immune system resemblance, suitable size, and longevity for clinical practical and monitoring purpose, SCID pigs bearing dysfunctional RAG could serve as important experimental tools for regenerative medicine, allograft and xenograft transplantation, and reconstitution experiments related to the immune system. In this study, we report the generation and phenotypic characterization of RAG1 and RAG2 knockout pigs using transcription activator-like effector nucleases. Porcine fetal fibroblasts were genetically engineered using transcription activator-like effector nucleases and then used to provide donor nuclei for somatic cell nuclear transfer. We obtained 27 live cloned piglets; among these piglets, 9 were targeted with biallelic mutations in RAG1, 3 were targeted with biallelic mutations in RAG2, and 10 were targeted with a monoallelic mutation in RAG2. Piglets with biallelic mutations in either RAG1 or RAG2 exhibited hypoplasia of immune organs, failed to perform V(D)J rearrangement, and lost mature B and T cells. These immunodeficient RAG1/2 knockout pigs are promising tools for biomedical and translational research.
Related JoVE Video
Enhancing the photocatalytic activity of bulk g-C3N4 by introducing mesoporous structure and hybridizing with graphene.
J Colloid Interface Sci
PUBLISHED: 06-20-2014
Show Abstract
Hide Abstract
Bulk graphitic carbon nitride (CN) suffers from small surface area and high recombination of charge carriers, which result in low photocatalytic activity. To enhance the activity of g-C3N4, the surface area should be enlarged and charge carrier separation should be promoted. In this work, a combined strategy was employed to dramatically enhance the activity of bulk g-C3N4 by simultaneously introducing mesoporous structure and hybridizing with graphene/graphene oxide. The mesoporous g-C3N4/graphene (MCN-G) and mesoporous g-C3N4/graphene oxide (MCN-GO) nanocomposites with enhanced photocatalytic activity (NO removal ratio of 64.9% and 60.7%) were fabricated via a facile sonochemical method. The visible light-harvesting ability of MCN-G and MCN-GO hybrids was enhanced and the conduction band was negatively shifted when 1.0 wt% graphene/graphene oxide was incorporated into the matrix of MCN. As electronic conductive channels, the G/GO sheets could efficiently facilitate the separation of chare carriers. MCN-G and MCN-GO exhibited drastically enhanced visible light photocatalytic activity toward NO removal. The NO removal ratio increased from 16.8% for CN to 64.9% for MCN-G and 60.7% for MCN-GO. This enhanced photocatalytic activity could be attributed to the increased surface area and pore volume, improved visible light utilization, enhanced reduction power of electrons, and promoted separation of charge carriers. This work demonstrates that a combined strategy is extremely effective for the development of active photocatalysts in environmental and energetic applications.
Related JoVE Video
Regional quantification of cerebral venous oxygenation from MRI susceptibility during hypercapnia.
Neuroimage
PUBLISHED: 06-18-2014
Show Abstract
Hide Abstract
There is an unmet medical need for noninvasive imaging of regional brain oxygenation to manage stroke, tumor, and neurodegenerative diseases. Oxygenation imaging from magnetic susceptibility in MRI is a promising new technique to measure local venous oxygen extraction fraction (OEF) along the cerebral venous vasculature. However, this approach has not been tested in vivo at different levels of oxygenation. The primary goal of this study was to test whether susceptibility imaging of oxygenation can detect OEF changes induced by hypercapnia, via CO2 inhalation, within selected a priori brain regions. Ten healthy subjects were scanned at 3T with a 32-channel head coil. The end-tidal CO2 (ETCO2) was monitored continuously and inspired gases were adjusted to achieve steady-state conditions of eucapnia (41±3mmHg) and hypercapnia (50±4mmHg). Gradient echo phase images and pseudo-continuous arterial spin labeling (pcASL) images were acquired to measure regional OEF and CBF respectively during eucapnia and hypercapnia. By assuming constant cerebral oxygen consumption throughout both gas states, regional CBF values were computed to predict the local change in OEF in each brain region. Hypercapnia induced a relative decrease in OEF of -42.3% in the straight sinus, -39.9% in the internal cerebral veins, and approximately -50% in pial vessels draining each of the occipital, parietal, and frontal cortical areas. Across volunteers, regional changes in OEF correlated with changes in ETCO2. The reductions in regional OEF (via phase images) were significantly correlated (P<0.05) with predicted reductions in OEF derived from CBF data (via pcASL images). These findings suggest that susceptibility imaging is a promising technique for OEF measurements, and may serve as a clinical biomarker for brain conditions with aberrant regional oxygenation.
Related JoVE Video
A semimetal bismuth element as a direct plasmonic photocatalyst.
Chem. Commun. (Camb.)
PUBLISHED: 06-17-2014
Show Abstract
Hide Abstract
The bismuth element synthesized by a facile chemical solution method exhibited an admirable and stable photocatalytic activity towards the removal of NO under 280 nm light irradiation due to the surface plasmon resonance mediated direct photocatalysis, and most strikingly, showed a catalytic "memory" capability following illumination.
Related JoVE Video
Sulfur nanocrystals confined in carbon nanotube network as a binder-free electrode for high-performance lithium sulfur batteries.
Nano Lett.
PUBLISHED: 06-06-2014
Show Abstract
Hide Abstract
A binder-free nano sulfur-carbon nanotube composite material featured by clusters of sulfur nanocrystals anchored across the superaligned carbon nanotube (SACNT) matrix is fabricated via a facile solution-based method. The conductive SACNT matrix not only avoids self-aggregation and ensures dispersive distribution of the sulfur nanocrystals but also offers three-dimensional continuous electron pathway, provides sufficient porosity in the matrix to benefit electrolyte infiltration, confines the sulfur/polysulfides, and accommodates the volume variations of sulfur during cycling. The nanosized sulfur particles shorten lithium ion diffusion path, and the confinement of sulfur particles in the SACNT network guarantees the stability of structure and electrochemical performance of the composite. The nano S-SACNT composite cathode delivers an initial discharge capacity of 1071 mAh g(-1), a peak capacity of 1088 mAh g(-1), and capacity retention of 85% after 100 cycles with high Coulombic efficiency (?100%) at 1 C. Moreover, at high current rates the nano S-SACNT composite displays impressive capacities of 1006 mAh g(-1) at 2 C, 960 mAh g(-1) at 5 C, and 879 mAh g(-1) at 10 C.
Related JoVE Video
Mixture of nonionic/ionic surfactants for the formulation of nanostructured lipid carriers: effects on physical properties.
Langmuir
PUBLISHED: 05-29-2014
Show Abstract
Hide Abstract
The objective of the present work was to investigate the effects of the mixture of nonionic/ionic surfactants on nanostructured lipid carriers (NLCs). Nonionic surfactant (polyethylene-poly(propylene glycol), Pluronic F68) and ionic surfactant (octenylsuccinic acid modified gum arabic, GA-OSA) were chosen as emulsifier for NLCs. The NLCs systems, which were composed of lipid matrix, modified 4-dedimethylaminosancycline (CMT-8), and various emulsifier agents, were characterized with dynamic light scattering (DLS), high performance liquid chromatography (HPLC), transmission electron microscopy (TEM), small-angle X-ray scattering (SAXS), differential scanning calorimetry (DSC), in vitro release, and phagocytosis assay. This mixture of nonionic/ionic surfactants showed significant effects on physical properties including particle size, polydispersity index (PDI), entrapment efficiency, and particle morphology. Compared with single stabilizer, this mixed nonionic/ionic surfactant system provided NLCs with better drug carrier properties including prolonged release profile and low phagocytosis by phagocyte. We expect that these explorations can provide a new strategy for the development of lipid nanoparticles as drug delivery.
Related JoVE Video
Vapor-condensation-assisted optical microscopy for ultralong carbon nanotubes and other nanostructures.
Nano Lett.
PUBLISHED: 05-28-2014
Show Abstract
Hide Abstract
Here we present a simple yet powerful approach for the imaging of nanostructures under an optical microscope with the help of vapor condensation on their surfaces. Supersaturated water vapor will first form a nanometer-sized water droplet on the condensation nuclei on the surface of nanostructures, and then the water droplet will grow bigger and scatter more light to make the outline of the nanostructure be visible under dark-field optical microscope. This vapor-condensation-assisted (VCA) optical microscopy is applicable to a variety of nanostructures from ultralong carbon nanotubes to functional groups, generating images with contrast coming from the difference in density of the condensation sites, and does not induce any impurities to the specimens. Moreover, this low-cost and efficient technique can be conveniently integrated with other facilities, such as Raman spectroscope and so forth, which will pave the way for widespread applications.
Related JoVE Video
Safety, tolerability, and pharmacokinetics of a single ascending dose of baicalein chewable tablets in healthy subjects.
J Ethnopharmacol
PUBLISHED: 05-22-2014
Show Abstract
Hide Abstract
The root of Scutellaria baicalensis Georgi, has been used extensively in traditional Chinese medicine for the treatment of inflammation, fever, cough, dysentery, and hypertension. Baicalein is a flavonoid isolated from the root of Scutellaria baicalensis Georgi, and is a novel neuroprotective agent under development for the treatment of Parkinson's disease. We aimed to investigate the pharmacokinetic (PK) properties of baicalein and its main metabolite, bacalin, after single-dose administration in healthy Chinese subjects. The safety and tolerability of baicalein were also assessed.
Related JoVE Video
[Targeted modification of CCR5 gene in rabbits by TALEN].
Yi Chuan
PUBLISHED: 05-22-2014
Show Abstract
Hide Abstract
The lack of suitable animal model for HIV-1 infection has become a bottleneck for the development of AIDS vaccines and drugs. Wild-type rabbits can be infected by HIV-1 persistently and HIV-1 can be efficiently replicated resulting in syncytia in rabbit cell line co-expressing human CD4 and CCR5.Therefore, a rabbit highly expressing human CD4 and CCR5 may be an ideal animal model for AIDS disease study. In the present report, by using the efficient gene targeting technology, transcription activator-like effector nuclease (TALEN), we explored the feasibility of generating a HIV-1 model by knocking in human CD4 and CCR5 into rabbit genome. First we constructed two TALEN vectors targeting rabbit CCR5 gene and a vector with homologous arms. TALEN mRNAs and donor DNA were then co-injected into fertilized oocytes. After 3?5 days, 24 embryos were collected and used to conduct mutation analysis with PCR and sequencing. All the 24 embryos were detected with CCR5 knockouts and 5 were human CD4 and CCR5 knockins. Our results laid a foundation for establishing a new animal model for the study of AIDS.
Related JoVE Video
In situ decoration of plasmonic Ag nanocrystals on the surface of (BiO)2CO3 hierarchical microspheres for enhanced visible light photocatalysis.
Dalton Trans
PUBLISHED: 05-15-2014
Show Abstract
Hide Abstract
Novel plasmonic 0D Ag nanocrystal decorated 3D (BiO)2CO3 hierarchical microspheres were fabricated with a one-pot hydrothermal method. The as-prepared samples were systematically characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, N2 adsorption-desorption isotherms, X-ray photoelectron spectroscopy, UV-vis diffuse reflectance spectroscopy, photoluminescence spectra, ns-level time-resolved fluorescence spectra, photocurrent generation and EIS measurement. The results indicated that the 0D Ag nanoparticles were deposited on the surface of 3D (BiO)2CO3 hierarchical microspheres. The deposited Ag nanoparticles were reduced from Ag(+) by the citrate ions from bismuth citrate. The photocatalytic activity of the as-prepared samples was evaluated towards the degradation of NO at ppb-level under visible light irradiation. The intermediate NO2 was monitored on-line during the photocatalytic reaction. The pure (BiO)2CO3 microspheres exhibited decent visible light photocatalytic activity because of the surface scattering and reflecting (SSR effect) resulting from the special 3D hierarchical architecture. The Ag-decorated (BiO)2CO3 microspheres (Ag/BOC) exhibited greatly enhanced photocatalytic activity, photocurrent generation and promoted NO2 oxidation compared to the pure (BiO)2CO3 microspheres. The enhanced photocatalytic activity and photocurrent generation of Ag/BOC was ascribed to the cooperative contribution of the surface plasmon resonance (SPR effect), efficient separation of electron-hole pairs and prolonged lifetime of charge carriers induced by Ag nanoparticles. The photocatalytic performance of Ag/BOC was dependent on the content of Ag loading. When the amount of Ag is controlled at 5%, the highest photocatalytic performance can be achieved. Further increasing the Ag loading content promotes aggregation of the Ag particles and transforms the uniform microspheres into non-uniform microspheres, which is not beneficial to improving the activity. Importantly, the as-prepared Ag/BOC composites exhibited high photochemical stability after multiple reaction runs. The concepts of enhancing the activity through the SSR and SPR effects provide a new avenue for the development of efficient noble metal/bismuth-based plasmonic photocatalysts with attractive nano/micro architectures for efficient visible light photocatalytic activity.
Related JoVE Video
Prevalence, awareness, treatment and control of hypertension in Henan Province, China.
Aust J Rural Health
PUBLISHED: 04-27-2014
Show Abstract
Hide Abstract
The present article aimed to explore and evaluate the epidemiology and determine the status of hypertension awareness, treatment and control in Henan province, China.
Related JoVE Video
Implanting iodine-125 seeds into rat dorsal root ganglion for neuropathic pain: neuronal microdamage without impacting hind limb motion.
Neural Regen Res
PUBLISHED: 04-22-2014
Show Abstract
Hide Abstract
The use of iodine-125 ((125)I) in cancer treatment has been shown to relieve patients' pain. Considering dorsal root ganglia are critical for neural transmission between the peripheral and central nervous systems, we assumed that (125)I could be implanted into rat dorsal root ganglia to provide relief for neuropathic pain. (125)I seeds with different radioactivity (0, 14.8, 29.6 MBq) were implanted separately through L4-5 and L5-6 intervertebral foramen into the vicinity of the L5 dorsal root ganglion. von Frey hair results demonstrated the mechanical pain threshold was elevated after implanting (125)I seeds from the high radioactivity group. Transmission electron microscopy revealed that nuclear membrane shrinkage, nucleolar margination, widespread mitochondrial swelling, partial vacuolization, lysosome increase, and partial endoplasmic reticulum dilation were visible at 1,440 hours in the low radioactivity group and at 336 hours in the high radioactivity group. Abundant nuclear membrane shrinkage, partial fuzzy nuclear membrane and endoplasmic reticulum necrosis were observed at 1,440 hours in the high radioactivity group. No significant difference in combined behavioral scores was detected between preoperation and postoperation in the low and high radioactivity groups. These results suggested that the mechanical pain threshold was elevated after implanting (125)I seeds without influencing motor functions of the hind limb, although cell injury was present.
Related JoVE Video
Mitigating the effects of Xuebijing injection on hematopoietic cell injury induced by total body irradiation with ? rays by decreasing reactive oxygen species levels.
Int J Mol Sci
PUBLISHED: 04-22-2014
Show Abstract
Hide Abstract
Hematopoietic injury is the most common side effect of radiotherapy. However, the methods available for the mitigating of radiation injury remain limited. Xuebijing injection (XBJ) is a traditional Chinese medicine used to treat sepsis in the clinic. In this study, we investigated the effects of XBJ on the survival rate in mice with hematopoietic injury induced by ? ray ionizing radiation (IR). Mice were intraperitoneally injected with XBJ daily for seven days after total body irradiation (TBI). Our results showed that XBJ (0.4 mL/kg) significantly increased 30-day survival rates in mice exposed to 7.5 Gy TBI. This effect may be attributable to improved preservation of white blood cells (WBCs) and hematopoietic cells, given that bone marrow (BM) cells from XBJ-treated mice produced more granulocyte-macrophage colony forming units (CFU-GM) than that in the 2 Gy/TBI group. XBJ also decreased the levels of reactive oxygen species (ROS) by increasing glutathione (GSH) and superoxide dismutase (SOD) levels in serum and attenuated the increased BM cell apoptosis caused by 2 Gy/TBI. In conclusion, these findings suggest that XBJ enhances the survival rate of irradiated mice and attenuates the effects of radiation on hematopoietic injury by decreasing ROS production in BM cells, indicating that XBJ may be a promising therapeutic candidate for reducing hematopoietic radiation injury.
Related JoVE Video
Polysaccharide isolated from Parmelia tinctorum ameliorates ionizing irradiation-induced damage in mice.
J. Radiat. Res.
PUBLISHED: 04-09-2014
Show Abstract
Hide Abstract
In this study, WPT-A, a type of water-soluble homogeneous lichen polysaccharide, was isolated and purified from Parmelia tinctorum. We investigated whether WPT-A has radioprotective effects when administered before total-body irradiation (TBI). Mice were treated with WPT-A via intraperitoneal injection (i.p.) once per day for three consecutive days prior to 7, 7.5, 8.5, 10 or 10.5-Gy TBI. Our results indicated that the survival rate was enhanced at a range of levels of TBI. The calculated dose reduction factor (DRF) was 1.2. White blood cell (WBC) counts, spleen colony forming units (CFU-S) and bone marrow nucleated cell (BMNC) counts were used to investigate the radioprotective effects of WPT-A on the hematopoietic system. The treatment groups received WPT-A at 20, 50 and 80 mg/kg b.w. doses before 6.5-Gy TBI and showed significantly higher BMNC and WBC counts compared with the radiation-only group. The groups administered 50 and 80 mg/kg b.w. WPT-A showed a significant increase in CFU-S compared with the radiation-only group. We also carried out a single cell gel electrophoresis assay to explore the radioprotective effects of WPT-A on DNA damage. The results from single-cell gel electrophoresis of peripheral blood leukocytes showed that WPT-A attenuated radiation-induced DNA damage. These results indicate a potential use for WPT-A as a radioprotector.
Related JoVE Video
Preformulation characterization and in vivo absorption in beagle dogs of JFD, a novel anti-obesity drug for oral delivery.
Drug Dev Ind Pharm
PUBLISHED: 04-04-2014
Show Abstract
Hide Abstract
Abstract JFD (N-isoleucyl-4-methyl-1,1-cyclopropyl-1-(4-chlorine)phenyl-2-amylamine·HCl) is a novel investigational anti-obesity drug without obvious cardiotoxicity. The objective of this study was to characterize the key physicochemical properties of JFD, including solution-state characterization (ionization constant, partition coefficient, aqueous and pH-solubility profile), solid-state characterization (particle size, thermal analysis, crystallinity and hygroscopicity) and drug-excipient chemical compatibility. A supporting in vivo absorption study was also carried out in beagle dogs. JFD bulk powders are prismatic crystals with a low degree of crystallinity, particle sizes of which are within 2-10??m. JFD is highly hygroscopic, easily deliquesces to an amorphous glass solid and changes subsequently to another crystal form under an elevated moisture/temperature condition. Similar physical instability was also observed in real-time CheqSol solubility assay. pKa (7.49?±?0.01), log?P (5.10?±?0.02) and intrinsic solubility (S0) (1.75??g/ml) at 37?°C of JFD were obtained using potentiometric titration method. Based on these solution-state properties, JFD was estimated to be classified as BCS II, thus its dissolution rate may be an absorption-limiting step. Moreover, JFD was more chemically compatible with dibasic calcium phosphate, mannitol, hypromellose and colloidal silicon dioxide than with lactose and magnesium stearate. Further, JFD exhibited an acceptable pharmacokinetic profiling in beagle dogs and the pharmacokinetic parameters Tmax, Cmax, AUC0-t and absolute bioavailability were 1.60?±?0.81?h, 0.78?±?0.47??g/ml, 3.77?±?1.85??g·h/ml and 52.30?±?19.39%, respectively. The preformulation characterization provides valuable information for further development of oral administration of JFD.
Related JoVE Video
Wave-CAIPI for highly accelerated 3D imaging.
Magn Reson Med
PUBLISHED: 03-28-2014
Show Abstract
Hide Abstract
To introduce the wave-CAIPI (controlled aliasing in parallel imaging) acquisition and reconstruction technique for highly accelerated 3D imaging with negligible g-factor and artifact penalties.
Related JoVE Video
[Inhibitory effect of resveratrol on expression of IL-1? in mesenchymal stem cells exposed to radiation].
Zhonghua Lao Dong Wei Sheng Zhi Ye Bing Za Zhi
PUBLISHED: 03-18-2014
Show Abstract
Hide Abstract
To investigate the inhibitory effect of resveratrol on interleukin-1? (IL-1?) production in mesenchymal stem cells (MSCs) exposed to radiation and the action mechanism of resveratrol.
Related JoVE Video
Ultrasmall Au(10-12)(SG)(10-12) nanomolecules for high tumor specificity and cancer radiotherapy.
Adv. Mater. Weinheim
PUBLISHED: 02-24-2014
Show Abstract
Hide Abstract
Radiosensitizers can increase local treatment efficacy under a relatively low and safe radiation dose, thereby facilitating tumor eradication and minimizing side effects. Here, a new class of radiosensitizers is reported, which contain several gold (Au) atoms embedded inside a peptide shell (e.g., Au10-12 (SG)10-12 ) and can achieve ultrahigh tumor uptake (10.86 SUV at 24 h post injection) and targeting specificity, efficient renal clearance, and high radiotherapy enhancement.
Related JoVE Video
Efficient natural-convective heat transfer properties of carbon nanotube sheets and their roles on the thermal dissipation.
ACS Appl Mater Interfaces
PUBLISHED: 02-20-2014
Show Abstract
Hide Abstract
In this work, we report our studies related to the natural-convective heat transfer properties of carbon nanotube (CNT) sheets. We theoretically derived the formulas and experimentally measured the natural-convective heat transfer coefficients (H) via electrical heating method. The H values of the CNT sheets containing different layers (1, 2, 3, and 1000) were measured. We found that the single-layer CNT sheet had a unique ability on heat dissipation because of its great H. The H value of the single-layer CNT sheet was 69 W/(m(2) K) which was about twice of aluminum foil in the same environment. As the layers increased, the H values dropped quickly to the same with that of aluminum foil. We also discussed its roles on thermal dissipation, and the results indicated that the convection was a significant way of dissipation when the CNT sheets were applied on macroscales. These results may give us a new guideline to design devices based on the CNT sheets.
Related JoVE Video
Regulation of proximal tubule vacuolar H(+)-ATPase by PKA and AMP-activated protein kinase.
Am. J. Physiol. Renal Physiol.
PUBLISHED: 02-19-2014
Show Abstract
Hide Abstract
The vacuolar H(+)-ATPase (V-ATPase) mediates ATP-driven H(+) transport across membranes. This pump is present at the apical membrane of kidney proximal tubule cells and intercalated cells. Defects in the V-ATPase and in proximal tubule function can cause renal tubular acidosis. We examined the role of protein kinase A (PKA) and AMP-activated protein kinase (AMPK) in the regulation of the V-ATPase in the proximal tubule as these two kinases coregulate the V-ATPase in the collecting duct. As the proximal tubule V-ATPases have different subunit compositions from other nephron segments, we postulated that V-ATPase regulation in the proximal tubule could differ from other kidney tubule segments. Immunofluorescence labeling of rat ex vivo kidney slices revealed that the V-ATPase was present in the proximal tubule both at the apical pole, colocalizing with the brush-border marker wheat germ agglutinin, and in the cytosol when slices were incubated in buffer alone. When slices were incubated with a cAMP analog and a phosphodiesterase inhibitor, the V-ATPase accumulated at the apical pole of S3 segment cells. These PKA activators also increased V-ATPase apical membrane expression as well as the rate of V-ATPase-dependent extracellular acidification in S3 cell monolayers relative to untreated cells. However, the AMPK activator AICAR decreased PKA-induced V-ATPase apical accumulation in proximal tubules of kidney slices and decreased V-ATPase activity in S3 cell monolayers. Our results suggest that in proximal tubule the V-ATPase subcellular localization and activity are acutely coregulated via PKA downstream of hormonal signals and via AMPK downstream of metabolic stress.
Related JoVE Video
Thoc1 inhibits cell growth via induction of cell cycle arrest and apoptosis in lung cancer cells.
Mol Med Rep
PUBLISHED: 02-11-2014
Show Abstract
Hide Abstract
THO complex 1 (Thoc1) is a human nuclear matrix protein that binds to the retinoblastoma tumor suppressor retinoblastoma protein (pRb). While some studies suggest that Thoc1 has characteristics of a tumor suppressor protein, whether Thoc1 can inhibit lung cancer cell growth is not clear. In the present study, we observed that Thoc1 is lowly expressed in the lung cancer cell lines SPC-A1 and NCI-H1975. Then, we investigated the potential effects of Thoc1 on lung cancer cell proliferation, cell cycle and apoptosis after stable transfection of these lines with a Thoc1 expression vector. We found that overexpression of Thoc1 can inhibit cell proliferation, induce G2/M cell cycle arrest and promote apoptosis. Further investigation indicated that overexpression of Thoc1 is involved in the inhibition of cell cycle-related proteins cyclin A1 and B1 and of pro-apoptotic factors Bax and caspase-3. In vivo experiments showed that tumors overexpressing Thoc1 display a slower growth rate than the control xenografts and show reduced expression of the protein Ki-67, which localized on the nuclear membrane. Taken together, our data show that in lung cancer cells, Thoc1 inhibits cell growth through induction of cell cycle arrest and apoptosis. These results indicate that Thoc1 may be used as a novel therapeutic target for human lung cancer treatment.
Related JoVE Video
Growth mechanism and photocatalytic activity of self-organized N-doped (BiO)?CO? hierarchical nanosheet microspheres from bismuth citrate and urea.
Dalton Trans
PUBLISHED: 02-11-2014
Show Abstract
Hide Abstract
Synthesis of nano-/microstructured functional materials with 3D hierarchical microspheres structure has provided new opportunities for optimizing their physical and chemical properties. This work revealed a new growth mechanism of self-organized N-doped (BiO)2CO3 hierarchical microspheres which were fabricated by hydrothermal treatment of bismuth citrate and urea without an additive. Based on time-dependent observation, several evolution processes were believed to account for the formation of the self-organized N-doped (BiO)2CO3 hierarchical microspheres. Initially, crystallized (BiO)4CO3(OH)2 particles were formed during the nucleation and crystallization processes. Subsequently, the intermediate (BiO)4CO3(OH)2 reacted with CO3(2-) to generate (BiO)2CO3 growth nuclei on the surface of the CO2 bubbles which can act as heterogeneous nucleation centers. Next, the (BiO)2CO3 growth nuclei aggregated together after the consumption of CO2 bubbles with the increased concentration of OH(-) and further grew to be nanosheets. The microspheres constructed by small nanosheets further grew with the consumption of small particles. Finally, all (BiO)4CO3(OH)2 transformed to the (BiO)2CO3 phase, accompanied by the doping of N element into the lattice of (BiO)2CO3, and thereby, the well-defined N-doped (BiO)2CO3 hierarchical microspheres were shaped. Depending on the distance between neighboring CO2 bubbles, the resulting microspheres can be linked or dispersed. Besides, the gradual release of CO2 bubbles and CO3(2-) played a crucial role in controlling the nucleation and growth process, resulting in different sizes of microspheres. The fabricated N-doped (BiO)2CO3 hierarchical microspheres displayed admirably efficient and durable photocatalytic activity under both UV and visible light towards removal of NO, which is mainly attributed to the introduction of N element and the special hierarchical structure. This work provides new insights into the controlled synthesis of photocatalytic nano/microstructures for potential environmental and energetic applications.
Related JoVE Video
Growth of BiOBr nanosheets on C3N4 nanosheets to construct two-dimensional nanojunctions with enhanced photoreactivity for NO removal.
J Colloid Interface Sci
PUBLISHED: 01-28-2014
Show Abstract
Hide Abstract
The development of approaches to effectively separate the photo-induced charge carriers is a key strategy to promote the photocatalytic activity of semiconductor photocatalysts. This work represents the construction of novel two-dimensional (2D) BiOBr/C3N4 nanojunctions by the growth of BiOBr nanosheets on the surface of C3N4 nanosheets at room temperature. The samples were characterized by XRD, FT-IR, TEM, UV-vis DRS and PL. The photocatalytic activity of the samples was evaluated by the removal of NO in air under visible light irradiation. The results indicated that electronic coupling took place between the {001} plane of BiOBr and {002} plane of C3N4. The BiOBr/C3N4 nanojunctions exhibited enhanced visible light photocatalytic activity compared with pure BiOBr and C3N4. The enhanced photoactivity can be mainly ascribed to the efficient separation and transportation of photo-induced electrons and holes due to the well-coupled crystal planes and well-matched band structures. The present work could provide new insights into the design and construction of 2D nanojunctions with well-matched crystal planes and band structures for efficient visible light photocatalysis.
Related JoVE Video
M-shaped grating by nanoimprinting: a replicable, large-area, highly active plasmonic surface-enhanced Raman scattering substrate with nanogaps.
Small
PUBLISHED: 01-27-2014
Show Abstract
Hide Abstract
Plasmonic nanostructures separated by nanogaps enable strong electromagnetic-field confinement on the nanoscale for enhancing light-matter interactions, which are in great demand in many applications such as surface-enhanced Raman scattering (SERS). A simple M-shaped nanograting with narrow V-shaped grooves is proposed. Both theoretical and experimental studies reveal that the electromagnetic field on the surface of the M grating can be pronouncedly enhanced over that of a grating without such grooves, due to field localization in the nanogaps formed by the narrow V grooves. A technique based on room-temperature nanoimprinting lithography and anisotropic reactive-ion etching is developed to fabricate this device, which is cost-effective, reliable, and suitable for fabricating large-area nanostructures. As a demonstration of the potential application of this device, the M grating is used as a SERS substrate for probing Rhodamine 6G molecules. Experimentally, an average SERS enhancement factor as high as 5×10? has been achieved, which verifies the greatly enhanced light-matter interaction on the surface of the M grating over that of traditional SERS surfaces.
Related JoVE Video
Radioprotective and antioxidant effect of resveratrol in hippocampus by activating Sirt1.
Int J Mol Sci
PUBLISHED: 01-25-2014
Show Abstract
Hide Abstract
Reactive oxygen species can lead to functional alterations in lipids, proteins, and nucleic acids, and an accumulation of ROS (Reactive oxygen species) is considered to be one factor that contributes to neurodegenerative changes. An increase in ROS production occurs following irradiation. Neuronal tissue is susceptible to oxidative stress because of its high oxygen consumption and modest antioxidant defenses. As a polyphenolic compound, resveratrol is frequently used as an activator of Sirt1 (Sirtuin 1). The present study was designed to explore the radioprotective and antioxidant effect of resveratrol on Sirt1 expression and activity induced by radiation and to provide a new target for the development of radiation protection drugs. Our results demonstrate that resveratrol inhibits apoptosis induced by radiation via the activation of Sirt1. We demonstrated an increase in Sirt1 mRNA that was present on 21 days of resveratrol treatment following irradiation in a concentration-dependent manner. Such mRNA increase was accompanied by an increase of Sirt1 protein and activity. Resveratrol effectively antagonized oxidation induced by irradiation, supporting its cellular ROS-scavenging effect. These results provide evidence that the mitochondrial protection and the antioxidant effect of resveratrol contribute to metabolic activity. These data suggest that Sirt1 may play an important role to protect neurons from oxidative stress.
Related JoVE Video
The incidence and distribution of surgical site infection in mainland china: a meta-analysis of 84 prospective observational studies.
Sci Rep
PUBLISHED: 01-22-2014
Show Abstract
Hide Abstract
Surgical site infection (SSI) is one of the most common surgical complications in the world, particularly in developing countries. This study aimed to estimate the incidence and distribution of SSI in mainland China. Eighty-four prospective observational studies (82 surveillance studies, 1 nested case control study, and 1 cohort study) were selected for inclusion in this meta-analysis. The average incidence of SSI in mainland China was 4.5% (95% CI: 3.1-5.8) from 2001 to 2012 and has decreased significantly in recent years. The remote western regions had a higher incidence of 4.6% (95% CI: 4.0-5.3). The most common surgical procedure was abdominal surgery (8.3%, 95% CI: 6.5-10.0). SSI occurred frequently in the elderly (5.1%, 95% CI: 2.2-8.0), patients confined to hospital for over 2 weeks (5.7%, 95% CI: 0.9-10.0), superficial incision wounds (5.6%, 95% CI: 4.4-6.8), dirty wounds (8.7%, 95% CI: 6.9-10.6), operations lasting for over 2?hours (7.3%, 95% CI: 4.9-9.7), general anaesthesia operations (4.7%, 95% CI: 2.7-6.6), emergency surgeries (5.9%, 95% CI: 4.2-7.7), and non-intra-medication operations (7.4%, 95% CI: 1.0-13.7).
Related JoVE Video
The in vitro and in vivo toxicity of graphene quantum dots.
Biomaterials
PUBLISHED: 01-21-2014
Show Abstract
Hide Abstract
Graphene quantum dots (GQD) generate intrinsic fluorescence, and improves aqueous stability of graphene oxide (GO) while maintaining wide chemical adaptability and high adsorption capacity. Despite GO's remarkable advantages in bio-imaging, bio-sensing and other biomedical applications, its biosafety issues are still unclear. Here we report a detailed and systematic study on the in vitro and in vivo toxicity of GQD. The GQD sample was prepared through a facile oxidation approach and fully characterized by means of AFM, TEM, FTIR, XPS and elemental analysis. In vitro experiments showed that GQD exhibits very low cytotoxicity owing to its ultra-small size and high oxygen content. Then, the in vivo biodistribution experiment of GQD revealed no material accumulation in main organs of mice and fast clearance of GQD through kidney. In order to mimic clinic drug administration, mice were injected with GQD and GO (as comparison) multiple times for in vivo toxicity tests. We found that GQD showed no obvious influence on mice owing to its small size, while GO appeared toxic, even caused death to mice due to GO aggregation inside mice. In brief, GQD possesses no obvious in vitro and in vivo toxicity, even under multi-dosing situation.
Related JoVE Video
shRNA-mediated XRCC2 gene knockdown efficiently sensitizes colon tumor cells to X-ray irradiation in vitro and in vivo.
Int J Mol Sci
PUBLISHED: 01-16-2014
Show Abstract
Hide Abstract
Colon cancer is one of the most common tumors of the digestive tract. Resistance to ionizing radiation (IR) decreased therapeutic efficiency in these patients' radiotherapy. XRCC2 is the key protein of DNA homologous recombination repair, and its high expression is associated with enhanced resistance to DNA damage induced by IR. Here, we investigated the effect of XRCC2 silencing on colon tumor cells' growth and sensitivity to X-radiation in vitro and in vivo. Colon tumor cells (T84 cell line) were cultivated in vitro and tumors originated from the cell line were propagated as xenografts in nude mice. The suppression of XRCC2 expression was achieved by using vector-based short hairpin RNA (shRNA) in T84 cells. We found that the knockdown of XRCC2 expression effectively decreased T84 cellular proliferation and colony formation, and led to cell apoptosis and cell cycle arrested in G2/M phase induced by X-radiation in vitro. In addition, tumor xenograft studies suggested that XRCC2 silencing inhibited tumorigenicity after radiation treatment in vivo. Our data suggest that the suppression of XRCC2 expression rendered colon tumor cells more sensitive to radiation therapy in vitro and in vivo, implying XRCC2 as a promising therapeutic target for the treatment of radioresistant human colon cancer.
Related JoVE Video
Reusable three-dimensional nanostructured substrates for surface-enhanced Raman scattering.
Nanoscale Res Lett
PUBLISHED: 01-13-2014
Show Abstract
Hide Abstract
To date, fabricating three-dimensional (3D) nanostructured substrate with small nanogap was a laborious challenge by conventional fabrication techniques. In this article, we address a simple, low-cost, large-area, and spatially controllable method to fabricate 3D nanostructures, involving hemisphere, hemiellipsoid, and pyramidal pits based on nanosphere lithography (NSL). These 3D nanostructures were used as surface-enhanced Raman scattering (SERS) substrates of single Rhodamine 6G (R6G) molecule. The average SERS enhancement factor achieved up to 1011. The inevitably negative influence of the adhesion-promoting intermediate layer of Cr or Ti was resolved by using such kind of 3D nanostructures. The nanostructured quartz substrate is a free platform as a SERS substrate and is nondestructive when altering with different metal films and is recyclable, which avoids the laborious and complicated fabricating procedures.
Related JoVE Video
Paris saponin ? inhibits metastasis by modulating matrix metalloproteinases in colorectal cancer cells.
Mol Med Rep
PUBLISHED: 01-08-2014
Show Abstract
Hide Abstract
Metastasis is the main cause of mortality of patients with cancer?related disease. Targeting the process of metastasis has been proposed as a potential strategy in cancer treatment. Trillium tschonoskii Maxim., a traditional Chinese medicine, is used for the treatment of numerous diseases, including cancer. The current study aimed to determine the anti?metastatic effect of Paris saponin VII (PS ?), which was extracted from T. tschonoskii Maxim., using SW620 and LoVo cells, two human metastatic colorectal cancer (CRC) cell lines. The present study conducted cell attachment, wound healing and migration assays to detect the anti?metastatic effects of PS VII on colorectal cells. In addition, gelatin zymography assay and western blot analysis were used to detect the possible mechanisms involved. The results of this study demonstrated that PS ? significantly suppresses the viability, attachment, migration and invasive abilities of CRC cells in a concentration?dependent manner. In addition, PS ? reduced the expression levels and activity of matrix metalloproteinase (MMP)?2 and MMP?9. These data indicate that PS ? reduces the metastatic capability of CRC cells, possibly via the downregulation of the expression and activity of MMP?2 and MMP?9. These results demonstrate a novel therapeutic potential for PS ? in anti?metastatic therapy.
Related JoVE Video
Fast image reconstruction with L2-regularization.
J Magn Reson Imaging
PUBLISHED: 01-08-2014
Show Abstract
Hide Abstract
We introduce L2-regularized reconstruction algorithms with closed-form solutions that achieve dramatic computational speed-up relative to state of the art L1- and L2-based iterative algorithms while maintaining similar image quality for various applications in MRI reconstruction.
Related JoVE Video
Enhanced optical output power of blue light-emitting diodes with quasi-aligned gold nanoparticles.
Nanoscale Res Lett
PUBLISHED: 01-06-2014
Show Abstract
Hide Abstract
The output power of the light from GaN-based light-emitting diodes (LEDs) was enhanced by fabricating gold (Au) nanoparticles on the surface of p-GaN. Quasi-aligned Au nanoparticle arrays were prepared by depositing Au thin film on an aligned suspended carbon nanotube thin film surface and then putting the Au-CNT system on the surface of p-GaN and thermally annealing the sample. The size and position of the Au nanoparticles were confined by the carbon nanotube framework, and no other additional residual Au was distributed on the surface of the p-GaN substrate. The output power of the light from the LEDs with Au nanoparticles was enhanced by 55.3% for an injected current of 100 mA with the electrical property unchanged compared with the conventional planar LEDs. The enhancement may originate from the surface plasmon effect and scattering effect of the Au nanoparticles.
Related JoVE Video
Neuromechanism Study of Insect-Machine Interface: Flight Control by Neural Electrical Stimulation.
PLoS ONE
PUBLISHED: 01-01-2014
Show Abstract
Hide Abstract
The insect-machine interface (IMI) is a novel approach developed for man-made air vehicles, which directly controls insect flight by either neuromuscular or neural stimulation. In our previous study of IMI, we induced flight initiation and cessation reproducibly in restrained honeybees (Apis mellifera L.) via electrical stimulation of the bilateral optic lobes. To explore the neuromechanism underlying IMI, we applied electrical stimulation to seven subregions of the honeybee brain with the aid of a new method for localizing brain regions. Results showed that the success rate for initiating honeybee flight decreased in the order: ?-lobe (or ?-lobe), ellipsoid body, lobula, medulla and antennal lobe. Based on a comparison with other neurobiological studies in honeybees, we propose that there is a cluster of descending neurons in the honeybee brain that transmits neural excitation from stimulated brain areas to the thoracic ganglia, leading to flight behavior. This neural circuit may involve the higher-order integration center, the primary visual processing center and the suboesophageal ganglion, which is also associated with a possible learning and memory pathway. By pharmacologically manipulating the electrically stimulated honeybee brain, we have shown that octopamine, rather than dopamine, serotonin and acetylcholine, plays a part in the circuit underlying electrically elicited honeybee flight. Our study presents a new brain stimulation protocol for the honeybee-machine interface and has solved one of the questions with regard to understanding which functional divisions of the insect brain participate in flight control. It will support further studies to uncover the involved neurons inside specific brain areas and to test the hypothesized involvement of a visual learning and memory pathway in IMI flight control.
Related JoVE Video
Distinct Epidermal Keratinocytes Respond to Extremely Low-Frequency Electromagnetic Fields Differently.
PLoS ONE
PUBLISHED: 01-01-2014
Show Abstract
Hide Abstract
Following an increase in the use of electric appliances that can generate 50 or 60 Hz electromagnetic fields, concerns have intensified regarding the biological effects of extremely low-frequency electromagnetic fields (ELF-EMFs) on human health. Previous epidemiological studies have suggested the carcinogenic potential of environmental exposure to ELF-EMFs, specifically at 50 or 60 Hz. However, the biological mechanism facilitating the effects of ELF-EMFs remains unclear. Cellular studies have yielded inconsistent results regarding the biological effects of ELF-EMFs. The inconsistent results might have been due to diverse cell types. In our previous study, we indicated that 1.5 mT, 60 Hz ELF-EMFs will cause G1 arrest through the activation of the ATM-Chk2-p21 pathway in human keratinocyte HaCaT cells. The aim of the current study was to investigate whether ELF-EMFs cause similar effects in a distinct epidermal keratinocyte, primary normal human epidermal keratinocytes (NHEK), by using the same ELF-EMF exposure system and experimental design. We observed that ELF-EMFs exerted no effects on cell growth, cell proliferation, cell cycle distribution, and the activation of ATM signaling pathway in NHEK cells. We demonstrated that the 2 epidermal keratinocytes responded to ELF-EMFs differently. To further validate this finding, we simultaneously exposed the NHEK and HaCaT cells to ELF-EMFs in the same incubator for 168 h and observed the cell growths. The simultaneous exposure of the two cell types results showed that the NHEK and HaCaT cells exhibited distinct responses to ELF-EMFs. Thus, we confirmed that the biological effects of ELF-EMFs in epidermal keratinocytes are cell type specific. Our findings may partially explain the inconsistent results of previous studies when comparing results across various experimental models.
Related JoVE Video
Light Spatial Distribution in the Canopy and Crop Development in Cotton.
PLoS ONE
PUBLISHED: 01-01-2014
Show Abstract
Hide Abstract
The partitioning of light is very difficult to assess, especially in discontinuous or irregular canopies. The aim of the present study was to analyze the spatial distribution of photosynthetically active radiation (PAR) in a heterogeneous cotton canopy based on a geo-statistical sampling method. Field experiments were conducted in 2011 and 2012 in Anyang, Henan, China. Field plots were arranged in a randomized block design with the main plot factor representing the plant density. There were 3 replications and 6 densities used in every replicate. The six plant density treatments were 15,000, 33,000, 51,000, 69,000, 87,000 and 105,000 plants ha-1. The following results were observed: 1) transmission within the canopy decreased with increasing density and significantly decreased from the top to the bottom of the canopy, but the greatest decreases were observed in the middle layers of the canopy on the vertical axis and closing to the rows along the horizontal axis; 2) the transmitted PAR (TPAR) of 6 different cotton populations decreased slowly and then increased slightly as the leaves matured, the TPAR values were approximately 52.6-84.9% (2011) and 42.7-78.8% (2012) during the early cotton developmental stage, and were 33.9-60.0% (2011) and 34.5-61.8% (2012) during the flowering stage; 3) the Leaf area index (LAI) was highly significant exponentially correlated (R2?=?0.90 in 2011, R2?=?0.91 in 2012) with the intercepted PAR (IPAR) within the canopy; 4) and a highly significant linear correlation (R2?=?0.92 in 2011, R2?=?0.96 in 2012) was observed between the accumulated IPAR and the biomass. Our findings will aid researchers to improve radiation-use efficiency by optimizing the ideotype for cotton canopy architecture based on light spatial distribution characteristics.
Related JoVE Video
Evaluation of Outbreak Detection Performance Using Multi-Stream Syndromic Surveillance for Influenza-Like Illness in Rural Hubei Province, China: A Temporal Simulation Model Based on Healthcare-Seeking Behaviors.
PLoS ONE
PUBLISHED: 01-01-2014
Show Abstract
Hide Abstract
Syndromic surveillance promotes the early detection of diseases outbreaks. Although syndromic surveillance has increased in developing countries, performance on outbreak detection, particularly in cases of multi-stream surveillance, has scarcely been evaluated in rural areas.
Related JoVE Video
Generation of multi-gene knockout rabbits using the Cas9/gRNA system.
Cell Regen (Lond)
PUBLISHED: 01-01-2014
Show Abstract
Hide Abstract
The prokaryotic clustered regularly interspaced short palindromic repeat (CRISPR)-associated system (Cas) is a simple, robust and efficient technique for gene targeting in model organisms such as zebrafish, mice and rats. In this report, we applied CRISPR technology to rabbits by microinjection of Cas9 mRNA and guided RNA (gRNA) into the cytoplasm of pronuclear-stage embryos. We achieved biallelic gene knockout (KO) rabbits by injection of 1 gene (IL2rg) or 2 gene (IL2rg and RAG1) Cas9 mRNA and gRNA with an efficiency of 100%. We also tested the efficiency of multiple gene KOs in early rabbit embryos and found that the efficiency of simultaneous gene mutation on target sites is as high as 100% for 3 genes (IL2rg, RAG1 and RAG2) and 33.3% for 5 genes (IL2rg, RAG1, RAG2, TIKI1 and ALB). Our results demonstrate that the Cas9/gRNA system is a highly efficient and fast tool not only for single-gene editing but also for multi-gene editing in rabbits.
Related JoVE Video
Production of transgenic pigs over-expressing the antiviral gene Mx1.
Cell Regen (Lond)
PUBLISHED: 01-01-2014
Show Abstract
Hide Abstract
The myxovirus resistance gene (Mx1) has a broad spectrum of antiviral activities. It is therefore an interesting candidate gene to improve disease resistance in farm animals. In this study, we report the use of somatic cell nuclear transfer (SCNT) to produce transgenic pigs over-expressing the Mx1 gene. These transgenic pigs express approximately 15-25 times more Mx1 mRNA than non-transgenic pigs, and the protein level of Mx1 was also markedly enhanced. We challenged fibroblast cells isolated from the ear skin of transgenic and control pigs with influenza A virus and classical swine fever virus (CFSV). Indirect immunofluorescence assay (IFA) revealed a profound decrease of influenza A proliferation in Mx1 transgenic cells. Growth kinetics showed an approximately 10-fold reduction of viral copies in the transgenic cells compared to non-transgenic controls. Additionally, we found that the Mx1 transgenic cells were more resistant to CSFV infection in comparison to non-transgenic cells. These results demonstrate that the Mx1 transgene can protect against viral infection in cells of transgenic pigs and indicate that the Mx1 transgene can be harnessed to develop disease-resistant pigs.
Related JoVE Video
Generation of knockout rabbits using transcription activator-like effector nucleases.
Cell Regen (Lond)
PUBLISHED: 01-01-2014
Show Abstract
Hide Abstract
Zinc-finger nucleases and transcription activator-like effector nucleases are novel gene-editing platforms contributing to redefine the boundaries of modern biological research. They are composed of a non-specific cleavage domain and a tailor made DNA-binding module, which enables a broad range of genetic modifications by inducing efficient DNA double-strand breaks at desired loci. Among other remarkable uses, these nucleases have been employed to produce gene knockouts in mid-size and large animals, such as rabbits and pigs, respectively. This approach is cost effective, relatively quick, and can produce invaluable models for human disease studies, biotechnology or agricultural purposes. Here we describe a protocol for the efficient generation of knockout rabbits using transcription activator-like effector nucleases, and a perspective of the field.
Related JoVE Video
Establishment of a Rabbit Oct4 Promoter-Based EGFP Reporter System.
PLoS ONE
PUBLISHED: 01-01-2014
Show Abstract
Hide Abstract
Rabbits are commonly used as laboratory animal models to investigate human diseases and phylogenetic development. However, pluripotent stem cells that contribute to germline transmission have yet to be established in rabbits. The transcription factor Oct4, also known as Pou5f1, is considered essential for the maintenance of the pluripotency of stem cells. Hence, pluripotent cells can be identified by monitoring Oct4 expression using a well-established Oct4 promoter-based reporter system. This study developed a rabbit Oct4 promoter-based enhanced green fluorescent protein (EGFP) reporter system by transfecting pROP2-EGFP into rabbit fetal fibroblasts (RFFs). The transgenic RFFs were used as donor cells for somatic cell nuclear transfer (SCNT). The EGFP expression was detected in the blastocysts and genital ridges of SCNT fetuses. Fibroblasts and neural stem cells (NSCs) were derived from the SCNT fetuses. EGFP was also reactivated in blastocysts after the second SCNT, and induced pluripotent stem cells (iPSCs) were obtained after reprogramming using Yamanaka's factors. The results above indicated that a rabbit reporter system used to monitor the differentiating status of cells was successfully developed.
Related JoVE Video
Systemic lymphoma arising from hydroa vacciniforme-like lymphoma: report of two cases with review of literature.
Int J Clin Exp Pathol
PUBLISHED: 01-01-2014
Show Abstract
Hide Abstract
Hydroa vacciniforme-like lymphoma (HVLL) is an extremely rare lymphoma described in children that occurs mainly in Asia and Latin American countries. It is an Epstein-Barr virus (EBV)-positive lymphoproliferative disease (LPD) characterized by a monoclonal proliferation of T or NK cells. In this study, we report the clinical and pathological features of two Chinese patients with HVLL showed T-cell phenotype expressing CD4. The two patients generally presented with similar clinical histories of waxing and waning ulcerative blistering lesions for ten years or more until progression to systemic lymphoma. One patient died two months after progression and another is alive with disease. In the two cases, persistence infection of EBV may be attributed to the disease progression, and systemic lymphoma arising from HVLL behaves in an aggressive fashion and is predisposing to chemotherapeutic agent resistance.
Related JoVE Video
Estimating the effectiveness of early control measures through school absenteeism surveillance in observed outbreaks at rural schools in Hubei, China.
PLoS ONE
PUBLISHED: 01-01-2014
Show Abstract
Hide Abstract
School absenteeism is a common data source in syndromic surveillance, which allows for the detection of outbreaks at an early stage. Previous studies focused on its correlation with other data sources. In this study, we evaluated the effectiveness of control measures based on early warning signals from school absenteeism surveillance in rural Chinese schools.
Related JoVE Video

What is Visualize?

JoVE Visualize is a tool created to match the last 5 years of PubMed publications to methods in JoVE's video library.

How does it work?

We use abstracts found on PubMed and match them to JoVE videos to create a list of 10 to 30 related methods videos.

Video X seems to be unrelated to Abstract Y...

In developing our video relationships, we compare around 5 million PubMed articles to our library of over 4,500 methods videos. In some cases the language used in the PubMed abstracts makes matching that content to a JoVE video difficult. In other cases, there happens not to be any content in our video library that is relevant to the topic of a given abstract. In these cases, our algorithms are trying their best to display videos with relevant content, which can sometimes result in matched videos with only a slight relation.