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.
Silver jewelry microanalysis with dual-pulse laser-induced breakdown spectroscopy: 266 + 1064??nm wavelength combination.
Appl Opt
PUBLISHED: 11-18-2014
Show Abstract
Hide Abstract
Orthogonal dual-wavelength dual-pulse laser-induced breakdown spectroscopy (ODWDP-LIBS) with 266+1064??nm wavelength combination was applied to realize silver jewelry microanalysis with enhanced sensitivity and minimal sample ablation. In this technique, the 266 nm laser with low pulse energy was selected as ablation laser and the time-delayed 1064 nm laser with moderate pulse energy was selected as reheating laser to enhance plasma emission. Significant signal enhancement was achieved under the excitation of the reheating laser without increasing mass ablation which was only determined by the ablation laser. Internal standard method was applied to realize quantitative analysis of copper impurity in silver jewelry samples. The calibration curve was built, and the limit of detection of copper in silver matrix was determined to be 37.4 ppm when the crater diameter was controlled at 6.5 ?m. This technique is especially useful for microanalysis of precious samples due to the property of less sample ablation in comparison with single-pulse laser-induced breakdown spectroscopy (SP-LIBS) under the same analytical sensitivity.
Related JoVE Video
PICK1 Mediates Synaptic Recruitment of AMPA Receptors at Neurexin-Induced Postsynaptic Sites.
J. Neurosci.
PUBLISHED: 11-14-2014
Show Abstract
Hide Abstract
In the CNS, synapse formation and maturation play crucial roles in the construction and consolidation of neuronal circuits. Neurexin and neuroligin localize on the opposite sides of synaptic membrane and interact with each other to promote the assembly and specialization of synapses. However, the excitatory synapses induced by the neurexin-neuroligin complex are initially immature synapses that lack AMPA receptors. Previously, PICK1 (protein interacting with C kinase 1) was shown to cluster and regulate the synaptic localization of AMPA receptors. Here, we report that during synaptogenesis induced by neurexin in cultured neurons from rat hippocampus, PICK1 recruited AMPA receptors to immature postsynaptic sites. This synaptic recruitment of AMPA receptors depended on the interaction between GluA2 and PICK1, and on the lipid-binding ability of PICK1, but not the interaction between PICK1 and neuroligin. Last, our results demonstrated that the recruitment of GluA2 to synapses could be prevented by ICA69 (islet cell autoantigen 69 kDa), a key binding partner of PICK1. Our study showed that PICK1, being negatively regulated by ICA69, could facilitate synapse maturation.
Related JoVE Video
[Safety and immunogenicity of seasonal inactivated influenza vaccine (split virion) and cross-reactive antibody responses to the H7N9 avian influenza virus].
Zhonghua Liu Xing Bing Xue Za Zhi
PUBLISHED: 11-08-2014
Show Abstract
Hide Abstract
To evaluate the safety and immunogenicity of seasonal inactivated influenza vaccine (split virion) and to analyze its cross-reactive antibody responses to H7N9 avian influenza virus.
Related JoVE Video
Xylose phosphorylation functions as a molecular switch to regulate proteoglycan biosynthesis.
Proc. Natl. Acad. Sci. U.S.A.
PUBLISHED: 10-20-2014
Show Abstract
Hide Abstract
Most eukaryotic cells elaborate several proteoglycans critical for transmitting biochemical signals into and between cells. However, the regulation of proteoglycan biosynthesis is not completely understood. We show that the atypical secretory kinase family with sequence similarity 20, member B (Fam20B) phosphorylates the initiating xylose residue in the proteoglycan tetrasaccharide linkage region, and that this event functions as a molecular switch to regulate subsequent glycosaminoglycan assembly. Proteoglycans from FAM20B knockout cells contain a truncated tetrasaccharide linkage region consisting of a disaccharide capped with sialic acid (Sia?2-3Gal?1-4Xyl?1) that cannot be further elongated. We also show that the activity of galactosyl transferase II (GalT-II, B3GalT6), a key enzyme in the biosynthesis of the tetrasaccharide linkage region, is dramatically increased by Fam20B-dependent xylose phosphorylation. Inactivating mutations in the GALT-II gene (B3GALT6) associated with Ehlers-Danlos syndrome cause proteoglycan maturation defects similar to FAM20B deletion. Collectively, our findings suggest that GalT-II function is impaired by loss of Fam20B-dependent xylose phosphorylation and reveal a previously unappreciated mechanism for regulation of proteoglycan biosynthesis.
Related JoVE Video
Visual-Patch-Attention-Aware Saliency Detection.
IEEE Trans Cybern
PUBLISHED: 10-08-2014
Show Abstract
Hide Abstract
The human visual system (HVS) can reliably perceive salient objects in an image, but, it remains a challenge to computationally model the process of detecting salient objects without prior knowledge of the image contents. This paper proposes a visual-attention-aware model to mimic the HVS for salient-object detection. The informative and directional patches can be seen as visual stimuli, and used as neuronal cues for humans to interpret and detect salient objects. In order to simulate this process, two typical patches are extracted individually and in parallel from the intensity channel and the discriminant color channel, respectively, as the primitives. In our algorithm, an improved wavelet-based salient-patch detector is used to extract the visually informative patches. In addition, as humans are sensitive to orientation features, and as directional patches are reliable cues, we also propose a method for extracting directional patches. These two different types of patches are then combined to form the most important patches, which are called preferential patches and are considered as the visual stimuli applied to the HVS for salient-object detection. Compared with the state-of-the-art methods for salient-object detection, experimental results using publicly available datasets show that our produced algorithm is reliable and effective.
Related JoVE Video
Interacting gene selection via cooperative game analysis for cancer diagnosis.
Biomed Mater Eng
PUBLISHED: 09-18-2014
Show Abstract
Hide Abstract
Microarray technologies offer practical diagnostic tools for cancer detection. One great challenge is to identify salient genes from the high dimensionality of microarray data that can directly contribute to the symptom of cancer. Interactions among genes have been recognized to be fundamentally important for understanding biological function. This paper proposes an interacting gene selection method for cancer classification by identifying useful interacting genes. The method firstly evaluates the interactivity degree of each gene according to the intricate interrelation among genes by cooperative game analysis. Then genes are selected in a forward way by considering both interactivity and relevance characters. Experimental comparisons are carried out on four publicly available microarray data sets with three outstanding gene selection methods. Moreover a gene set enrichment analysis is also performed on the selected gene subset. The results show that the proposed method achieves better classification performance and enrichment score than other gene selection methods.
Related JoVE Video
Automatic recognition of facial movement for paralyzed face.
Biomed Mater Eng
PUBLISHED: 09-18-2014
Show Abstract
Hide Abstract
Facial nerve paralysis is a common disease due to nerve damage. Most approaches for evaluating the degree of facial paralysis rely on a set of different facial movements as commanded by doctors. Therefore, automatic recognition of the patterns of facial movement is fundamental to the evaluation of the degree of facial paralysis. In this paper, a novel method named Active Shape Models plus Local Binary Patterns (ASMLBP) is presented for recognizing facial movement patterns. Firstly, the Active Shape Models (ASMs) are used in the method to locate facial key points. According to these points, the face is divided into eight local regions. Then the descriptors of these regions are extracted by using Local Binary Patterns (LBP) to recognize the patterns of facial movement. The proposed ASMLBP method is tested on both the collected facial paralysis database with 57 patients and another publicly available database named the Japanese Female Facial Expression (JAFFE). Experimental results demonstrate that the proposed method is efficient for both paralyzed and normal faces.
Related JoVE Video
Efficacy and safety of vitamin D3 in patients with diabetic nephropathy: a meta-analysis of randomized controlled trials.
Chin. Med. J.
PUBLISHED: 08-23-2014
Show Abstract
Hide Abstract
Several studies found that vitamin D3 might alter glucose metabolism, protect kidney from injury and even proposed the mechanisms. But results from previous studies have been conflicting. The aim of this study was to evaluate the efficacy and safety of vitamin D3 in patients with diabetic nephropathy. The underlying mechanism of vitamin D3 decreasing proteinuria is also discussed.
Related JoVE Video
Genome-wide analysis of miRNA signature in the APPswe/PS1?E9 mouse model of alzheimer's disease.
PLoS ONE
PUBLISHED: 08-22-2014
Show Abstract
Hide Abstract
Alzheimer's disease (AD) is the most common cause of dementia. One of the pathological hallmarks of AD is amyloid ? (A?) deposition. MicroRNAs (miRNAs) are small non-coding RNAs whose expression levels change significantly during neuronal pathogenesis and may be used as diagnostic markers. Some miRNAs are important in AD development by targeting genes responsible for A? metabolism. However, a systematic assessment of the miRNA expression profile induced by A?-mediated neuronal pathogenesis is still lacking. In the present study, we examined miRNA expression profile by using the APPswe/PS1?E9 mouse model of AD. Two sibling pairs of mice were examined, showing 30 and 24 miRNAs with significantly altered expression levels from each paired control, respectively. Nine known miRNAs were common in both groups. Prediction of putative target genes and functional annotation implied that these altered miRNAs affect many target genes mainly involved in PI3K/Akt signaling pathway. This study provides a general profile of miRNAs regulated by A?-associated signal pathways, which is helpful to understand the mechanism of A?-induced neuronal dysfunction in AD development.
Related JoVE Video
Self-assembly of a Ag nanoparticle-modified and graphene-wrapped TiO2 nanobelt ternary heterostructure: surface charge tuning toward efficient photocatalysis.
Nanoscale
PUBLISHED: 08-19-2014
Show Abstract
Hide Abstract
In recent years, tremendous research efforts have been made towards developing graphene (GR)-based nanocomposites for photocatalytic applications. In this work, surface-coarsened TiO2 nanobelts (SC-TNBs) closely enwrapped with monodispersed Ag nanoparticles (NPs) and GR nanosheets (i.e. Ag/GR/SC-TNBs) were fabricated using a facile self-assembly strategy followed by photoreduction. It was found that the as-prepared Ag/GR/SC-TNBs ternary heterostructure exhibited significantly improved photocatalytic performances under irradiation with UV light in comparison with blank SC-TNBs and its binary counterparts owing to the formation of double heterojunctions among the components. The intimate integration of Ag NPs and GR with SC-TNBs achieved by the self-assembly buildup exerts a profound effect on the transfer of photogenerated electrons over the SC-TNBs substrate in which Ag NPs serve as an efficient "electron reservoir" and GR as an electron transporter and collector, thus concurrently prolonging the lifetime of the photogenerated electron-hole pairs and resulting in the remarkably enhanced photoactivity over the Ag/GR/SC-TNBs ternary nanocomposite. In addition, the underlying photocatalytic mechanism was elucidated and the primary active species were determined.
Related JoVE Video
MiR-7b directly targets DC-STAMP causing suppression of NFATc1 and c-Fos signaling during osteoclast fusion and differentiation.
Biochim. Biophys. Acta
PUBLISHED: 08-11-2014
Show Abstract
Hide Abstract
DC-STAMP is a key regulating molecule of osteoclastogenesis and osteoclast precursor (OCP) fusion. Emerging lines of evidence showed that microRNAs play crucial roles in bone metabolism and osteoclast differentiation, but no microRNA has yet been reported to be directly related to OCPs fusion. Through a microarray, we found that the expression of miR-7b in RAW264.7 cells was significantly decreased after induction with M-CSF and RANKL. The overexpression of miR-7b in RAW264.7 cells attenuated the number of TRAP-positive cells number and the formation of multinucleated cells, whereas the inhibition of miR-7b enhanced osteoclastogenesis. Through a dual luciferase reporter assay, we confirmed that miR-7b directly targets DC-STAMP. Other fusogenic molecules, such as CD47, ATP6v0d2, and OC-STAMP, were detected to be down-regulated in accordance with the inhibition of DC-STAMP. Because DC-STAMP also participates in osteoclast differentiation through the ITAM-ITIM network, multiple osteoclast-specific genes in the ITAM-ITIM network were detected to identify how DC-STAMP is involved in this process. The results showed that molecules associated with the ITAM-ITIM network, such as NFATc1 and OSCAR, which are crucial in osteoclastogenesis, were consistently altered due to DC-STAMP inhibition. These findings suggest that miR-7b inhibits osteoclastogenesis and cell-cell fusion by directly targeting DC-STAMP. In addition, the inhibition of DC-STAMP and its downstream signals changed the expression of other fusogenic genes and key regulating genes, such as Nfatc1, c-fos, Akt, Irf8, Mapk1, and Traf6. In conclusion, our findings indicate that miR-7b may be a potential therapeutic target for the treatment of osteoclast-related bone disorders.
Related JoVE Video
Pharmacodynamic Monitoring of Mammalian Target of Rapamycin Inhibition by Phosphoflow Cytometric Determination of p70S6 Kinase Activity.
Transplantation
PUBLISHED: 08-08-2014
Show Abstract
Hide Abstract
Immunosuppressive therapy with mammalian target of rapamycin inhibitors (mTORi) requires maintenance of an effective inhibition of the alloimmune response, whereas reducing drug-related nephrotoxicity. Therapeutic monitoring is based on mTORi trough levels, which do not necessarily reflect biologic effects on the PI3K-Akt-mTOR pathway and hence may often result in under-immunosuppression or over-immunosuppression.
Related JoVE Video
Paclitaxel- and/or cisplatin-induced ocular neurotoxicity: a case report and literature review.
Onco Targets Ther
PUBLISHED: 07-31-2014
Show Abstract
Hide Abstract
Paclitaxel (PTX) and/or cisplatin (CDDP), as important cytotoxic anti-cancer agents, are widely used to treat various solid tumors. Both may cause moderate or severe neurotoxicity, but ocular neurotoxicity is also occasionally reported. A patient diagnosed with nasopharyngeal cancer suffering acute ocular neurotoxicity 10 days after paclitaxel and CDDP administration at the recommended dose is described in the present case report, and PTX- and/or CDDP-induced ocular neurotoxicity are summarized according to previous reports. Possible mechanisms and the potential diagnostic, therapeutic and predictive strategies of PTX- and/or CDDP-induced ocular neurotoxicity are reviewed, to help the oncologist to take the infrequent toxicity of cytotoxic drugs into account and improve patient safety during anti-cancer therapy.
Related JoVE Video
CD38 is highly expressed and affects the PI3K/Akt signaling pathway in cervical cancer.
Oncol. Rep.
PUBLISHED: 07-18-2014
Show Abstract
Hide Abstract
Cervical cancer is the second most common cancer and the fifth most deadly malignancy in females worldwide, affecting 500,000 individuals each year. It is the leading cause of cancer mortality among women in developing countries. Dysregulated activation of genes, such as CD44, SOX9 and SKP2, plays a role in cervical cancer. CD38 is known to be involved in activities typical of cell surface receptors, such as signaling for activation and proliferation events and heterotypic cell adhesion. CD38 contributes to disease progression and relapse in certain tumors, such as acute myeloid and chronic lymphocytic leukemia. To the best of our knowledge, there is currently no report on the relationship between CD38 and cervical cancer. Using qPCR, immunohistochemistry, and western blot analysis, the expression levels of CD38 were investigated and found to be upregulated in cervical cancer. CD38 was correlated with dysregulation of the phosphatidylinositol 3-kinase (PI3K)/Akt signaling pathway in cervical cancer tissues in vitro. At the same time, CD38 overexpression affected the expression of PI3K, Akt, MDM2 and p53 in vivo. The results of the present study suggested that CD38 is highly expressed in cervical carcinoma tissues and play an important role in dysregulation of the PI3K/Akt signaling pathway.
Related JoVE Video
Improving abiotic reducing ability of hydrothermal biochar by low temperature oxidation under air.
Bioresour. Technol.
PUBLISHED: 07-14-2014
Show Abstract
Hide Abstract
Oxidized hydrothermal biochar was prepared by hydrothermal carbonization of Spartina alterniflora biomass (240°C for 4h) and subsequent oxidization (240°C for 10min) under air. Oxidized hydrochar achieved a Fe(III) reducing capacity of 2.15mmol/g at pH 2.0 with 120h, which is 1.2 times higher than un-oxidized hydrochar. Low temperature oxidization increases the contents of carboxyl and carbonyl groups on hydrochar surface. It is supposed that carboxyl groups provide bonding sites for soluble Fe species and carbonyl groups are responsible for Fe(3+) reduction. A Fenton-like process was established with Fe(2+) replaced by oxidized hydrochar and tested for methylene blue (MB) decoloration. Oxidized hydrochar achieved a MB decolorization (200mg/L, pH 7.0) rate of 99.21% within 3h and demonstrates prominent prevail over H2O2 absent control test. This study reveals low temperature oxidization is an effective way to improve and restore abiotic reducing ability of hydrochar.
Related JoVE Video
Renal F4/80+CD11c+ Mononuclear Phagocytes Display Phenotypic and Functional Characteristics of Macrophages in Health and in Adriamycin Nephropathy.
J. Am. Soc. Nephrol.
PUBLISHED: 07-12-2014
Show Abstract
Hide Abstract
Conventional markers of macrophages (M?s) and dendritic cells (DCs) lack specificity and often overlap, leading to confusion and controversy regarding the precise function of these cells in kidney and other diseases. This study aimed to identify the phenotype and function of renal mononuclear phagocytes (rMPs) expressing key markers of both M?s and DCs. F4/80(+)CD11c(+) cells accounted for 45% of total rMPs in normal kidneys and in those from mice with Adriamycin nephropathy (AN). Despite expression of the DC marker CD11c, these double-positive rMPs displayed the features of M?s, including M?-like morphology, high expression of CD68, CD204, and CD206, and high phagocytic ability but low antigen-presenting ability. F4/80(+)CD11c(+) cells were found in the cortex but not in the medulla of the kidney. In AN, F4/80(+)CD11c(+) cells displayed an M1 M? phenotype with high expression of inflammatory mediators and costimulatory factors. Adoptive transfer of F4/80(+)CD11c(+) cells separated from diseased kidney aggravated renal injury in AN mice. Furthermore, adoptive transfer of common progenitors revealed that kidney F4/80(+)CD11c(+) cells were derived predominantly from monocytes, but not from pre-DCs. In conclusion, renal F4/80(+)CD11c(+) cells are a major subset of rMPs and display M?-like phenotypic and functional characteristics in health and in AN.
Related JoVE Video
DNA methylome profiling of maternal peripheral blood and placentas reveal potential fetal DNA markers for non-invasive prenatal testing.
Mol. Hum. Reprod.
PUBLISHED: 07-04-2014
Show Abstract
Hide Abstract
Utilizing epigenetic (DNA methylation) differences to differentiate between maternal peripheral blood (PBL) and fetal (placental) DNA has been a promising strategy for non-invasive prenatal testing (NIPT). However, the differentially methylated regions (DMRs) have yet to be fully ascertained. In the present study, we performed genome-wide comparative methylome analysis between maternal PBL and placental DNA from pregnancies of first trimester by methylated DNA immunoprecipitation-sequencing (MeDIP-Seq) and Infinium HumanMethylation450 BeadChip assays. A total of 36 931 DMRs and 45 804 differentially methylated sites (DMSs) covering the whole genome, exclusive of the Y chromosome, were identified via MeDIP-Seq and Infinium 450k array, respectively, of which 3759 sites in 2188 regions were confirmed by both methods. Not only did we find the previously reported potential fetal DNA markers in our identified DMRs/DMSs but also we verified fully the identified DMRs/DMSs in the validation round by MassARRAY EpiTYPER. The screened potential fetal DNA markers may be used for NIPT on aneuploidies and other chromosomal diseases, such as cri du chat syndrome and velo-cardio-facial syndrome. In addition, these potential markers may have application in the early diagnosis of placental dysfunction, such as pre-eclampsia.
Related JoVE Video
Ildr1b is essential for semicircular canal development, migration of the posterior lateral line primordium and hearing ability in zebrafish: implications for a role in the recessive hearing impairment DFNB42.
Hum. Mol. Genet.
PUBLISHED: 07-02-2014
Show Abstract
Hide Abstract
Immunoglobulin-like domain containing receptor 1 (ILDR1) is a poorly characterized gene that was first identified in lymphoma cells. Recently, ILDR1 has been found to be responsible for autosomal recessive hearing impairment DFNB42. Patients with ILDR1 mutations cause bilateral non-progressive moderate-to-profound sensorineural hearing impairment. However, the etiology and mechanism of ILDR1-related hearing loss remains to be elucidated. In order to uncover the pathology of DFNB42 deafness, we used the morpholino injection technique to establish an ildr1b-morphant zebrafish model. Ildr1b-morphant zebrafish displayed defective hearing and imbalanced swimming, and developmental delays were seen in the semicircular canals of the inner ear. The gene expression profile and real-time PCR revealed down-regulation of atp1b2b (encoding Na(+)/K(+) transporting, beta 2b polypeptide) in ildr1b-morphant zebrafish. We found that injection of atp1b2b mRNA into ildr1b-knockdown zebrafish could rescue the phenotype of developmental delay of the semicircular canals. Moreover, ildr1b-morphant zebrafish had reduced numbers of lateral line neuromasts due to the disruption of lateral line primordium migration. In situ hybridization showed the involvement of attenuated FGF signaling and the chemokine receptor 4b (cxcr4b) and chemokine receptor 7b (cxcr7b) in posterior lateral line primordium of ildr1b-morphant zebrafish. We concluded that Ildr1b is crucial for the development of the inner ear and the lateral line system. This study provides the first evidence for the mechanism of Ildr1b on hearing in vivo and sheds light on the pathology of DFNB42.
Related JoVE Video
Why do rough surfaces appear glossy?
J Opt Soc Am A Opt Image Sci Vis
PUBLISHED: 07-01-2014
Show Abstract
Hide Abstract
The majority of work on the perception of gloss has been performed using smooth surfaces (e.g., spheres). Previous studies that have employed more complex surfaces reported that increasing mesoscale roughness increases perceived gloss [Psychol. Sci.19, 196 (2008), J. Vis.10(9), 13 (2010), Curr. Biol.22, 1909 (2012)]. We show that the use of realistic rendering conditions is important and that, in contrast to [Psychol. Sci.19, 196 (2008), J. Vis.10(9), 13 (2010)], after a certain point increasing roughness further actually reduces glossiness. We investigate five image statistics of estimated highlights and show that for our stimuli, one in particular, which we term "percentage of highlight area," is highly correlated with perceived gloss. We investigate a simple model that explains the unimodal, nonmonotonic relationship between mesoscale roughness and percentage highlight area.
Related JoVE Video
Efficacy of isolated left ventricular and biventricular pacing is differentially associated with baseline QRS duration in chronic heart failure: a meta-analysis of randomized controlled trials.
Heart Fail Rev
PUBLISHED: 06-25-2014
Show Abstract
Hide Abstract
Cardiac resynchronization therapy can treat chronic heart failure through either biventricular pacing (BVP) or isolated left ventricular pacing (LVP), and the efficacy is depended on QRS duration. However, the optimal therapeutic choice of pacing or how the QRS influences the efficacy remains uncertain. To investigate this uncertainty, we searched available publications in PubMed, EMBASE, and the Cochrane Central Register of Controlled Trials databases regarding differentials in efficacy parameters between BVP and LVP. A meta-analysis of eight randomized controlled trials found that BVP and LVP were comparable with regard to quality-of-life scores, left ventricular ejection fraction, left ventricular end-systolic volume, and mortality or heart transplant rates. However, there was a significant heterogeneity among the trials in 6-min walking distances. Subsequent meta-regression indicated that the baseline QRS duration significantly correlated with the standard mean difference between BVP and LVP. As QRS duration increased, the gain in 6-min walking distance with BVP became significantly greater than that of LVP. This suggests that it is necessary to consider the QRS duration when comparing the clinical effects of BVP and LVP.
Related JoVE Video
Spatiotemporal pH dynamics in concentration polarization near ion-selective membranes.
Langmuir
PUBLISHED: 06-25-2014
Show Abstract
Hide Abstract
We present a detailed analysis of the transient pH dynamics for a weak, buffered electrolyte subject to voltage-driven transport through an ion-selective membrane. We show that pH fronts emanate from the concentration polarization zone next to the membrane and that these propagating fronts change the pH in the system several units from its equilibrium value. The analysis is based on a 1D model using the unsteady Poisson-Nernst-Planck equations with nonequilibrium chemistry and without assumptions of electroneutrality or asymptotically thin electric double layers. Nonequilibrium chemical effects, especially for water splitting, are shown to be important for the dynamical and spatiotemporal evolution of the pH fronts. Nonetheless, the model also shows that at steady state the assumption of chemical equilibrium can still lead to good approximations of the global pH distribution. Moreover, our model shows that the transport of the hydronium ion in the extended space charge region is governed by a balance between electromigration and water self-ionization. On the basis of this observation, we present a simple model showing that the net flux of the hydronium ion is proportional to the length of the extended space charge region and the water self-ionization rate. To demonstrate these effects in practice, we have adopted the experiment of Mai et al. (Mai, J.; Miller, H.; Hatch, A. V. Spatiotemporal Mapping of Concentration Polarization Induced pH Changes at Nanoconstrictions. ACS Nano 2012, 6, 10206) as a model problem, and by including the full chemistry and transport, we show that the present model can capture the experimentally observed pH fronts. Our model can, among other things, be used to predict and engineer pH dynamics, which can be essential to the performance of membrane-based systems for biochemical separation and analysis.
Related JoVE Video
The synergistic regulation of VEGF-mediated angiogenesis through miR-190 and target genes.
RNA
PUBLISHED: 06-24-2014
Show Abstract
Hide Abstract
VEGF is a major contributor to angiogenesis, a vital process in normal growth and development and tumor transition. However, the current clinical efficacy of VEGF inhibitors is limited, and the molecular mechanism underlying VEGF regulation remains to be elucidated. Here we show that miR-190 directly targets a group of angiogenic effectors besides VEGF per se. Noted, these effectors can transcriptionally regulate VEGF expression in an intracellular or intercellular manner, thus demonstrating that miR-190 modulates the VEGF-mediated tumor angiogenesis at three levels. The synergistic effect of miR-190 and its target genes demonstrates a complex but apparently more stable system, allowing for the tight control of the level of VEGF. Finally, we showed that miR-190 significantly suppresses tumor metastasis, especially angiogenesis. Together, these results indicate that miR-190 is a promising antitumor target in clinical applications.
Related JoVE Video
Subnatural-linewidth polarization-entangled photon pairs with controllable temporal length.
Phys. Rev. Lett.
PUBLISHED: 06-20-2014
Show Abstract
Hide Abstract
We demonstrate an efficient experimental scheme for producing polarization-entangled photon pairs from spontaneous four-wave mixing (SFWM) in a laser-cooled (85)Rb atomic ensemble, with a bandwidth (as low as 0.8 MHz) much narrower than the rubidium atomic natural linewidth. By stabilizing the relative phase between the two SFWM paths in a Mach-Zehnder interferometer configuration, we are able to produce all four Bell states. These subnatural-linewidth photon pairs with polarization entanglement are ideal quantum information carriers for connecting remote atomic quantum nodes via efficient light-matter interaction in a photon-atom quantum network.
Related JoVE Video
Targeted Delivery of Tumor Suppressor microRNA-1 by Transferrin- Conjugated Lipopolyplex Nanoparticles to Patient-Derived Glioblastoma Stem Cells.
Curr Pharm Biotechnol
PUBLISHED: 06-12-2014
Show Abstract
Hide Abstract
Among heterogeneous glioblastoma multiforme (GBM) cells, glioblastoma stem cells (GSCs) is a subpopulation having a critical role in tumor initiation and therapy resistance. Thus targeting GSCs would be an essential step to completely eradicate this lethal disease. MicroRNA-1 (miR-1) expression is deregulated in GBM patients and restoration of miR-1 by viral-vector in GBM cells has been demonstrated to inhibit tumor initiation and attenuate cell migration. Here, we show that a transferrin-targeting non-invasive nanoparticle delivery system (Tf-NP) can efficiently deliver miR-1 to GBM patient-derived GSC-enriched sphere cultures (GBM spheres).
Related JoVE Video
Complete mitochondrial genome of Aphis gossypii Glover (Hemiptera: Aphididae).
Mitochondrial DNA
PUBLISHED: 05-29-2014
Show Abstract
Hide Abstract
Abstract The complete mitochondrial genome of the cotton-melon aphid, Aphis gossypii Glover, was sequenced using a combination of high-throughput sequencing, traditional PCR amplification, and Sanger sequencing. The genome is 15,869?bp in length, and contains 37 typical coding genes, one non-coding AT-rich region, and a repeat region found exclusively in aphids. The base composition of the genome is A (45.4%), T (38.3%), C (10.4%), and G (5.9%). All protein coding genes start with a typical ATN initiation codon; all genes use the standard termination codon (TAA) except ND4 that ends with a single TA.
Related JoVE Video
Chemically Tailoring Coal to Fluorescent Carbon Dots with Tuned Size and Their Capacity for Cu(II) Detection.
Small
PUBLISHED: 05-14-2014
Show Abstract
Hide Abstract
The desired control of size, structure, and optical properties of fluorescent carbon dots (CDs) is critical for understanding the fluorescence mechanism and exploring their potential application. Herein, a top-down strategy to chemically tailor the inexpensive coal to fluorescent CDs by a combined method of carbonization and acidic oxidation etching is reported. The size and optical properties of the as-made CDs are tuned by controlling the structures of graphitic crystallites in the starting precursor. The coal-derived CDs exhibit two different distinctive emission modes, where the intensity of the short-wavelength emission is significantly enhanced by partial reduction treatment. The evolution of the electronic structure and the surface states analysis show that two different types of fluorescence centers, nano-sized sp(2) carbon domains and surface defects, are responsible for the observed emission characteristics. The reduced CDs are demonstrated as an effective fluorescent sensing material for label-free and selective detection of Cu(II) ions with a detection limit as low as 2.0 nm, showing a great promise for real-world sensor applications.
Related JoVE Video
The mechanism of anti-osteoporosis effects of 3-hydroxybutyrate and derivatives under simulated microgravity.
Biomaterials
PUBLISHED: 04-24-2014
Show Abstract
Hide Abstract
Skeletons have significant bone loss (osteoporosis) under microgravity environment. This study showed that microbial polyhydroxyalkanoates (PHA) degradation product, and also ketone body 3-hydroxybutyrate acid (3HB) and its derivative 3-hydroxybutyrate methyl ester (3HBME) inhibit the development of osteoporosis in mice maintained under simulated microgravity, helping preserve bone microstructure and mechanical property. Mice orally administrated with 3HB or 3HBME recovered much more quickly from osteoporosis resulted from simulated microgravity compared with the controls without 3HB or 3HBME treatments due to less calcium loss to the sera. It was known that abnormal activation of osteoclasts induced by microgravity led to bone tissue absorption and thus osteoporosis. In this study, it was found that 3HB or 3HBME down-regulated the nuclear factor of activated T-cells cytoplasmic 1 (NFATc1), which is the transcription factor of pre-osteoclast differentiation. When NFATc1 activation and downstream functions were inhibited, 3HB or 3HBME was able to strongly reduce pre-osteoclast differentiation. As a result, bone absorption was prevented. It was demonstrated that 100 mg/kg 3HB resulted in the most obvious effect on osteoporosis prevention. Based on these results, 3HB and 3HBME should be further developed as novel drug candidates against osteoporosis induced by microgravity.
Related JoVE Video
miR-19b promotes tumor growth and metastasis via targeting TP53.
RNA
PUBLISHED: 04-17-2014
Show Abstract
Hide Abstract
Tumor suppressor TP53 (or p53) is one of the most important regulators in numerous physiological and pathological processes. Recently, the miRNA-mediated post-transcription regulation of p53 has been studied. However, systematic studies of miRNA targeting sites within the p53 gene are still a challenging task. Here, we developed a dual-color assay capable of identifying miRNA targeting sites in a certain gene, specifically p53, in a simple, direct, and robust manner. Results showed that p53 was a direct and critical target of miR-19b, but not miR-19a, regardless of sequence similarity. Overexpression of miR-19b observed in human cancer cells can diminish p53 protein levels and, subsequently, downstream components such as Bax and p21. This miR-19b-mediated p53 reduction was shown to promote cell cycle, cell migration or invasion, and repress senescence and apoptosis in vitro. Further investigation revealed that miR-19b controls tumor growth and metastasis in vivo. Therefore, it is possible that miR-19b antagomirs or sponges could be developed as therapeutic agents against tumor development.
Related JoVE Video
An important amino acid in nucleoprotein contributes to influenza A virus replication by interacting with polymerase PB2.
Virology
PUBLISHED: 04-16-2014
Show Abstract
Hide Abstract
The nucleoprotein (NP) of influenza A virus plays a critical role in the formation of viral ribonucleoprotein (vRNP) complex. However, it remains unclear which key residues in NP are associated with the assembly of vRNP and contribute to virus replication. Here, a highly conserved aspartic acid at residue 88 (D88) of NP was identified by molecular docking of NP with the Fv region of a broad-spectrum anti-NP mAb 19C10 and further demonstrated to be an important residue contributes to the RNP activity, virus growth in MDCK cells and replication in lungs of infected mice by comparing recombinant wild-type A/WSN/1933 virus to the mutant virus that contains an alanine instead of aspartic acid at NP residue 88. D88 was also predicted to interact with PB2 by molecular docking and further verified by immunoprecipitation. These findings provide new information for understanding the interaction between NP and other polymerase subunits in virus replication.
Related JoVE Video
Effects of drought after pollination on grain yield and quality of fresh waxy maize.
J. Sci. Food Agric.
PUBLISHED: 04-16-2014
Show Abstract
Hide Abstract
Waxy maize is consumed as a vegetable when harvested at fresh stage (23-26 days after pollination) in China. Fresh waxy maize is normally grown under rain-fed conditions and suffers drought frequently during plant growth. The effect of drought on grain development of fresh waxy maize is not known.
Related JoVE Video
Protective roles of nitric oxide on seed germination and seedling growth of rice (Oryza sativa L.) under cadmium stress.
Ecotoxicol. Environ. Saf.
PUBLISHED: 04-06-2014
Show Abstract
Hide Abstract
Nitric oxide (NO) is a bioactive molecule in plants which mediates a variety of physiological processes and responses to biotic and abiotic stresses including heavy metals. In the present study, the effects of exogenous NO donor sodium nitroprusside (SNP) on rice seed germination and seedlings growth were investigated under Cd stress and a possible mechanism was postulated. The results indicated that 100?M Cd significantly decreased rice seed germination index, vigor index, root and shoot lengths as well as fresh weight compared to control. Exogenous SNP dose-dependently attenuated the inhibition of rice seed germination and thereafter seedling growth caused by Cd. The promoting effect was most pronounced at 30?M SNP. Cd exposure caused oxidative stress by elevating hydrogen peroxide (H2O2) and malondialdehyde (MDA) contents in root and shoot of rice seedlings. 30?M SNP counteracted partly Cd toxicity by reducing the H2O2 and MDA contents of Cd-exposed seedlings. Meanwhile, application of SNP markedly stimulated the activities of superoxide dismutases (SOD), ascorbate peroxidases (APX), guaiacol peroxidase (POD) and catalases (CAT) compared with Cd treatment alone, thereby indicating the enhancement of the antioxidative capacity in the root and shoot under Cd stress. In addition, addition of 30?M SNP increased accumulation of proline in both root and shoot. The Cd accumulation in seedlings was significant reduced by SNP, implicating that the protective role of SNP was responsible for preventing Cd accumulation. However, the effects of SNP were reverted by addition of cPTIO, a NO scavenger, suggesting the protective roles of SNP might be related to the induction of NO. Furthermore, K3Fe(CN)6 and [Formula: see text] / [Formula: see text] had no similar roles as SNP. Based on these results, it can be concluded that SNP exerted an advantageous effect on alleviating the inhibitory effect of Cd on rice seed germination and seedling growth, which might interact with NO.
Related JoVE Video
Electrophysiological characteristics of left atrial diverticulum in patients with atrial fibrillation: electrograms, impedance and clinical implications.
Int. J. Cardiol.
PUBLISHED: 03-30-2014
Show Abstract
Hide Abstract
Left atrial diverticulum (LAD) is not rare in patients with atrial fibrillation (AF). Recent reports focused on its morphology however data on its electrophysiological characteristics are lacking. Our study aims to investigate the electrogram and impedance features of LAD.
Related JoVE Video
Dynamic regulation of FGF23 by Fam20C phosphorylation, GalNAc-T3 glycosylation, and furin proteolysis.
Proc. Natl. Acad. Sci. U.S.A.
PUBLISHED: 03-26-2014
Show Abstract
Hide Abstract
The family with sequence similarity 20, member C (Fam20C) has recently been identified as the Golgi casein kinase. Fam20C phosphorylates secreted proteins on Ser-x-Glu/pSer motifs and loss-of-function mutations in the kinase cause Raine syndrome, an often-fatal osteosclerotic bone dysplasia. Fam20C is potentially an upstream regulator of the phosphate-regulating hormone fibroblast growth factor 23 (FGF23), because humans with FAM20C mutations and Fam20C KO mice develop hypophosphatemia due to an increase in full-length, biologically active FGF23. However, the mechanism by which Fam20C regulates FGF23 is unknown. Here we show that Fam20C directly phosphorylates FGF23 on Ser(180), within the FGF23 R(176)XXR(179)/S(180)AE subtilisin-like proprotein convertase motif. This phosphorylation event inhibits O-glycosylation of FGF23 by polypeptide N-acetylgalactosaminyltransferase 3 (GalNAc-T3), and promotes FGF23 cleavage and inactivation by the subtilisin-like proprotein convertase furin. Collectively, our results provide a molecular mechanism by which FGF23 is dynamically regulated by phosphorylation, glycosylation, and proteolysis. Furthermore, our findings suggest that cross-talk between phosphorylation and O-glycosylation of proteins in the secretory pathway may be an important mechanism by which secreted proteins are regulated.
Related JoVE Video
A 17-fold increase of trifluoroacetic acid in landscape waters of Beijing, China during the last decade.
Chemosphere
PUBLISHED: 03-25-2014
Show Abstract
Hide Abstract
The concentrations of trifluoroacetic acid (TFA) were measured in urban landscape waters, tap water and snows in Beijing, China in 2012. Compared with the 2002 measurements, a 17-fold increase from 23-98ngL(-1) to 345-828ngL(-1) was observed for TFA concentrations in urban landscape waters, and an obvious increase from not detected (n.d.) to 155ngL(-1) occurred to TFA in tap water. By flux estimation between air and water interface, the remarkable increase of TFA was attributable to dry and wet deposition. The quantitative water-air-sediment interaction (QWASI) model simulated TFAs in various environmental media and showed that, over 99% of TFA distributed in water bodies. Our results recommend that measures are needed to control the increase of TFA in China.
Related JoVE Video
Efficacy, safety, and immunogenicity of an enterovirus 71 vaccine in China.
N. Engl. J. Med.
PUBLISHED: 02-28-2014
Show Abstract
Hide Abstract
Enterovirus 71 (EV71) is one of the major causative agents of outbreaks of hand, foot, and mouth disease or herpangina worldwide. This phase 3 trial was designed to evaluate the efficacy, safety, and immunogenicity of an EV71 vaccine.
Related JoVE Video
The organochlorine p,p'-dichlorodiphenyltrichloroethane induces colorectal cancer growth through Wnt/?-catenin signaling.
Toxicol. Lett.
PUBLISHED: 01-15-2014
Show Abstract
Hide Abstract
Dichlorodiphenyltrichloroethane (DDT), an organochlorine pollutant, is associated with several types of cancer. However, the relationship between DDT and colorectal cancer is uncertain. In this study, the impact of p,p'-DDT on colorectal cancer growth was evaluated using both in vitro and in vivo models. Our results indicated that the proliferation of human colorectal adenocarcinoma DLD1 cells was significantly promoted after exposed to low concentrations of p,p'-DDT ranging from 10(-12) to 10(-7) M for 96 h. Exposure to p,p'-DDT from 10(-10) to 10(-8) M led to upregulation of phospho-GSK3? (Ser9), ?-catenin, c-Myc and cyclin D1 in DLD1 cells. RNA interference of ?-catenin inhibited the proliferation of DLD1 cells stimulated by p,p'-DDT. Inhibiting of estrogen receptors (ERs) had no significant effect on the action of p,p'-DDT. Treatment with p,p'-DDT induced production of intracellular reactive oxygen species (ROS) and inhibited superoxide dismutase (SOD) activity in DLD1 cells. Treatment with N-acetyl-L-cysteine (NAC), a ROS inhibitor, suppressed the induction of Wnt/?-catenin signaling and DLD1 cell proliferation by p,p'-DDT. Moreover, in a mouse xenograft model, 5 nmol/kg p,p'-DDT resulted in increased tumor size, oxidative stress and Wnt/?-catenin signaling. These results indicated that low concentrations of p,p'-DDT promoted colorectal cancer growth through Wnt/?-catenin signaling, which was mediated by oxidative stress. The finding suggests an association between low concentrations of p,p'-DDT exposure and colorectal cancer progression.
Related JoVE Video
Catalytic conversion of biomass pyrolysis-derived compounds with chemical liquid deposition (CLD) modified ZSM-5.
Bioresour. Technol.
PUBLISHED: 01-14-2014
Show Abstract
Hide Abstract
Chemical liquid deposition (CLD) with KH550, TEOS and methyl silicone oil as the modifiers was used to modify ZSM-5 and deposit its external acid sites. The characteristics of modified catalysts were tested by catalytic conversion of biomass pyrolysis-derived compounds. The effects of different modifying conditions (deposited amount, temperature, and time) on the product yields and selectivities were investigated. The results show KH550 modified ZSM-5 (deposited amount of 4%, temperature of 20°C and time of 6h) produced the maximum yields of aromatics (24.5%) and olefins (16.5%), which are much higher than that obtained with original ZSM-5 catalyst (18.8% aromatics and 9.8% olefins). The coke yield decreased from 44.1% with original ZSM-5 to 26.7% with KH550 modified ZSM-5. The selectivities of low-molecule-weight hydrocarbons (ethylene and benzene) decreased, while that of higher molecule-weight hydrocarbons (propylene, butylene, toluene, and naphthalene) increased comparing with original ZSM-5.
Related JoVE Video
A secreted tyrosine kinase acts in the extracellular environment.
Cell
PUBLISHED: 01-13-2014
Show Abstract
Hide Abstract
Although tyrosine phosphorylation of extracellular proteins has been reported to occur extensively in vivo, no secreted protein tyrosine kinase has been identified. As a result, investigation of the potential role of extracellular tyrosine phosphorylation in physiological and pathological tissue regulation has not been possible. Here, we show that VLK, a putative protein kinase previously shown to be essential in embryonic development, is a secreted protein kinase, with preference for tyrosine, that phosphorylates a broad range of secreted and ER-resident substrate proteins. We find that VLK is rapidly and quantitatively secreted from platelets in response to stimuli and can tyrosine phosphorylate coreleased proteins utilizing endogenous as well as exogenous ATP sources. We propose that discovery of VLK activity provides an explanation for the extensive and conserved pattern of extracellular tyrosine phosphophorylation seen in vivo, and extends the importance of regulated tyrosine phosphorylation into the extracellular environment.
Related JoVE Video
?-Elemene against human lung cancer via up-regulation of P53 protein expression to promote the release of exosome.
Lung Cancer
PUBLISHED: 01-09-2014
Show Abstract
Hide Abstract
?-Elemene, a novel antitumor plant drug extracted from the traditional Chinese medicinal herb Zedoary, has been shown to be effective against a wide variety of tumors. Recent studies have indicated that ?-elemene can inhibit the growth of lung cancer cells; however, the exact mechanism of ?-element's action in lung cancer remains largely unknown. In the present study, the antitumor effect of ?-elemene on human lung cancer cells and the mechanism involved has been investigated.
Related JoVE Video
A novel gastroretentive porous microparticle for anti-Helicobacter pylori therapy: preparation, in vitro and in vivo evaluation.
Int J Pharm
PUBLISHED: 01-06-2014
Show Abstract
Hide Abstract
Gastroretentive drug delivery system is a promising option for the treatment of Helicobacter pylori infection, which can prolong gastric residence time and supply high drug concentration in the stomach. In the present study, a low density system of metronidazole-loaded porous Eudragit® RS microparticle with high drug loading capacity (>25%) was fabricated via electrospray method. The porous structure and size distribution of microparticles were affected by polymer concentration and flow rate of solution. FTIR and XRD analyses indicated that drug has been entrapped into the porous microparticles. In addition, sustained release profiles and slight cytotoxicity in vitro were detected. Gamma scintigraphy study in vivo demonstrated that ¹³¹I-labeled microparticles retained in stomach for over 8h, and about 65.50% radioactive counts were finally detected in the region of interest. The biodistribution study confirmed that hotspot of radioactivity was remaining in the stomach. Furthermore, metronidazole-loaded porous microparticles can eradicate H. pylori completely with lower dose and administration frequency of antibiotic compared with pure drug, which were also more helpful for the healing of mucosal damages. These results suggest that prepared porous microparticle has the potential to provide better treatment for H. pylori infection.
Related JoVE Video
Human and mouse skeletal muscle stem cells: convergent and divergent mechanisms of myogenesis.
PLoS ONE
PUBLISHED: 01-01-2014
Show Abstract
Hide Abstract
Satellite cells are the chief contributor to skeletal muscle growth and regeneration. The study of mouse satellite cells has accelerated in recent years due to technical advancements in the isolation of these cells. The study of human satellite cells has lagged and thus little is known about how the biology of mouse and human satellite cells compare. We developed a flow cytometry-based method to prospectively isolate human skeletal muscle progenitors from the satellite cell pool using positive and negative selection markers. Results show that this pool is enriched in PAX7 expressing cells that possess robust myogenic potential including the ability to give rise to de novo muscle in vivo. We compared mouse and human satellite cells in culture and identify differences in the elaboration of the myogenic genetic program and in the sensitivity of the cells to cytokine stimulation. These results indicate that not all mechanisms regulating mouse satellite cell activation are conserved in human satellite cells and that such differences may impact the clinical translation of therapeutics validated in mouse models. Thus, the findings of this study are relevant to developing therapies to combat muscle disease.
Related JoVE Video
Promoter methylation assay of SASH1 gene in breast cancer.
J BUON
PUBLISHED: 12-18-2013
Show Abstract
Hide Abstract
Purpose: To analyze the relationship between the expression of SASH1 and its methylation level of SASH1 gene promoter in human breast cancer. Methods: Expression levels of SASH1 were examined in breast cancer tissues and adjacent normal tissues with immunohistochemistry and with real time PCR (RT-PCR) methylation analysis was performed with MassArray. Results: Immunohistochemistry showed that SASH1 expression was strongly reduced in breast cancer compared with adjacent normal tissues. Quantitative methylation analysis by MassArray revealed that CpG sites in SASH1 promoter shared similar methylation pattern in tumor tissue and adjacent normal tissue. The CpG sites with significant difference in methylation level were CpG_26.27 and CpG_54.55. Moreover, 5-aza-2-deoxycytidine (5-Aza-dc) treatment of tumor cell line MDA-MB-231 caused significant elevation of SASH1 mRNA. Conclusion: Based on these data, we propose that increase of DNA methylation level in the promoter region of gene SASH1, particularly CpG_26.27 or CpG_54.55 sites, possibly repressed SASH1 expression in breast cancer.
Related JoVE Video
Fast Serial Analysis of Active Cholesterol at the Plasma Membrane in Single Cells.
Anal. Chem.
PUBLISHED: 12-16-2013
Show Abstract
Hide Abstract
Previously, our group has utilized the luminol electrochemiluminescence to analyze the active cholesterol at the plasma membrane in single cells by the exposure of one cell to a photomultiplier tube (PMT) through a pinhole. In this paper, fast analysis of active cholesterol at the plasma membrane in single cells was achieved by a multimicroelectrode array without the pinhole. Single cells were directly located on the microelectrodes using cell-sized microwell traps. A cycle of voltage was applied on the microelectrodes sequentially to induce a peak of luminescence from each microelectrode for the serial measurement of active membrane cholesterol. A minimal time of 1.60 s was determined for the analysis of one cell. The simulation and the experimental data exhibited a semisteady-state distribution of hydrogen peroxide on the microelectrode after the reaction of cholesterol oxidase with the membrane cholesterol, which supported the relative accuracy of the serial analysis. An eight-microelectrode array was demonstrated to analyze eight single cells in 22 s serially, including the channel switching time. The results from 64 single cells either activated by low ion strength buffer or the inhibition of intracellular acyl-coA/cholesterol acyltransferase (ACAT) revealed that most of the cells analyzed had the similar active membrane cholesterol, while few cells had more active cholesterol resulting in the cellular heterogeneity. The fast single-cell analysis platform developed will be potentially useful for the analysis of more molecules in single cells using proper oxidases.
Related JoVE Video
Detection of Extracellular RNAs in Cancer and Viral Infection via Tethered Cationic Lipoplex Nanoparticles Containing Molecular Beacons.
Anal. Chem.
PUBLISHED: 11-13-2013
Show Abstract
Hide Abstract
Noninvasive early detection methods have the potential to reduce mortality rates of both cancer and infectious diseases. Here, we present a novel assay by which tethered cationic lipoplex nanoparticles containing molecular beacons (MBs) can capture cancer cell-derived exosomes or viruses and identify encapsulated RNAs in a single step. A series of ultracentrifugation and Exoquick isolation kit were first used to isolate exosomes from the cell culture medium and human serum, respectively. Cationic lipoplex nanoparticles linked onto the surface of a thin glass plate capture negatively charged viruses or cell-secreted exosomes by electrostatic interactions to form larger nanoscale complexes. Lipoplex/virus or lipoplex/exosome fusion leads to the mixing of viral/exosomal RNAs and MBs within the lipoplexes. After the target RNAs specially bind to the MBs, exosomes enriched in target RNAs are readily identified by the fluorescence signals of MBs. The in situ detection of target extracellular RNAs without diluting the samples leads to high detection sensitivity not achievable by existing methods, e.g., quantitative reverse transcription-polymerase chain reaction (qRT-PCR). Here we demonstrate this concept using lentivirus and serum from lung cancer patients.
Related JoVE Video
Role of pncA and rpsA Gene Sequencing in Detection of Pyrazinamide Resistance in Mycobacterium tuberculosis Isolates from Southern China.
J. Clin. Microbiol.
PUBLISHED: 10-16-2013
Show Abstract
Hide Abstract
We sequenced pncA and rpsA genes plus flanking regions of 161 Mycobacterium tuberculosis isolates and found 10 new pncA and 3 novel rpsA mutations in pyrazinamide-resistant strains determined by the Bactec MGIT 960 system. The 3 end of rpsA might be added as the target of molecular detection of pyrazinamide susceptibility.
Related JoVE Video
The circuit of polychromator for Experimental Advanced Superconducting Tokamak edge Thomson scattering diagnostic.
Rev Sci Instrum
PUBLISHED: 10-05-2013
Show Abstract
Hide Abstract
The detector circuit is the core component of filter polychromator which is used for scattering light analysis in Thomson scattering diagnostic, and is responsible for the precision and stability of a system. High signal-to-noise and stability are primary requirements for the diagnostic. Recently, an upgraded detector circuit for weak light detecting in Experimental Advanced Superconducting Tokamak (EAST) edge Thomson scattering system has been designed, which can be used for the measurement of large electron temperature (T(e)) gradient and low electron density (n(e)). In this new circuit, a thermoelectric-cooled avalanche photodiode with the aid circuit is involved for increasing stability and enhancing signal-to-noise ratio (SNR), especially the circuit will never be influenced by ambient temperature. These features are expected to improve the accuracy of EAST Thomson diagnostic dramatically. Related mechanical construction of the circuit is redesigned as well for heat-sinking and installation. All parameters are optimized, and SNR is dramatically improved. The number of minimum detectable photons is only 10.
Related JoVE Video
Rapid detection of trace bacteria in biofluids using porous monoliths in microchannels.
Biosens Bioelectron
PUBLISHED: 08-23-2013
Show Abstract
Hide Abstract
We present advancements in microfluidic technology for rapid detection of as few as 10 rickettsial organisms in complex biological samples. An immuno-reactive filter, macroporous polyacrylamide monolith (PAM), fabricated within a microfluidic channel enhances solid-phase immuno-capture, staining and detection of targeted bacteria. Bacterial cells in samples flowing through the channel are forced to interact with the PAM filter surface due to size exclusion, overcoming common transport and kinetic limitations for rapid (min), high-efficiency (~100%) capture. In the process, targeted cells in sample volumes of 10?l to >100?l are concentrated within a sub-50nl region at the PAM filter edge in the microchannel, thus concentrating them over 1000-fold. This significantly increases sensitivity, as the hydrophilic PAM also yields low non-specific immuno-fluorescence backgrounds with samples including serum, blood and non-targeted bacteria. The concentrated target cells are detected using fluorescently-labeled antibodies. With a single 2.0×2.0×0.3mm PAM filter, as few as 10 rickettsial organisms per 100µl of lysed blood sample can be analyzed within 60min, as compared to hours or even days needed for conventional detection methods. This method is highly relevant to rapid, multiplexed, low-cost point of care diagnostics at early stages of infection where diagnostics providing more immediate and actionable test results are needed to improve patient outcomes and mitigate potential natural and non-natural outbreaks or epidemics of rickettsial diseases.
Related JoVE Video
Exposure assessment, chemical characterization and source identification of PM2.5 for school children and industrial downwind residents in Guangzhou, China.
Environ Geochem Health
PUBLISHED: 08-01-2013
Show Abstract
Hide Abstract
To assess the exposure doses of PM2.5 and to investigate its chemical components for the subpopulation (i.e., school children and industrial downwind residents), simultaneous sampling of indoor and outdoor PM2.5 was conducted at an elementary school close to traffic arteries and a residence located in the downwind area of a steel plant in metropolitan Guangzhou in 2010. Chemical components, i.e., organic carbon, elemental carbon and 6 water soluble ions were analyzed in PM2.5. A survey was also conducted to investigate the time-activity patterns of the school children and the industrial downwind residents. Indoor and outdoor PM2.5 were 63.2 ± 20.1 and (76.7 ± 35.8) ?g/m(3) at the school, and 118.8 ± 44.7 and 125.7 ± 57.1 ?g/m(3) in the community, respectively. Indoor PM2.5 was found to be highly related to outdoor sources, and stationary sources were the significant contributors to PM2.5 at both sites. The daily average doses of PM2.5 for the school children at the school (D children) and the industrial downwind residents in the community (D residents) were (7.6 ± 1.9) and (36.1 ± 36.8) ?g/kg-day, respectively. The daily average doses of particulate organic mass and SO4 (2-) were the two most abundant chemical components in PM2.5. PM2.5 exposure for the school children was contributed by indoor and outdoor environments by 48.8 and 51.2 %, respectively; for the industrial downwind residents, the contributions were 66.0 and 34.0 %, respectively. Age and body weight were significantly and negatively correlated with D children, while age, body weight and education level were significantly and negatively correlated with D residents; gender was not a significant factor at both cases.
Related JoVE Video
Unexpected catalytic performance in silent tantalum oxide through nitridation and defect chemistry.
J. Am. Chem. Soc.
PUBLISHED: 07-24-2013
Show Abstract
Hide Abstract
This work reports on the preparation of a noble-metal-free and highly active catalyst that proved to be an efficient and green reductant with renewable capacity. Nitridation of a silent Ta1.1O1.05 substrate led to the formation of a series of TaOxNy hollow nanocrystals that exhibited outstanding activity toward catalytic reduction of nitrobenzenes under ambient conditions. ESR and XPS results indicated that defective nitrogen species and oxygen vacancies at the surfaces of the TaOxNy nanocrystals may play synergetic roles in the reduction of nitrobenzenes. The underlying mechanism is completely different from those previously reported for metallic nanoparticles. This work may provide new possibilities for the development of novel defect-meditated catalytic systems and offer a strategy for tuning any catalysts from silent to highly reactive by carefully tailoring the chemical composition and surface defect chemistry.
Related JoVE Video
Phosphorylation of substrates destined for secretion by the Fam20 kinases.
Biochem. Soc. Trans.
PUBLISHED: 07-19-2013
Show Abstract
Hide Abstract
Since the discovery of protein kinases, protein phosphorylation has emerged as a key regulatory mechanism. The majority of phosphoproteins reside within the nucleus and cytoplasm; however, many secreted proteins are phosphorylated by unknown kinases located within the secretory pathway and/or in the extracellular space. The Fam20 kinases are emerging as the enzymes responsible for phosphorylating secreted proteins and proteoglycans. Evolutionary analysis reveals that these kinases are exclusively present in metazoans and contain conserved features that are common among all eukaryotic protein kinases. Mutations in the Fam20 family members cause disorders of biomineralization in humans that highlight the physiological significance of secreted protein phosphorylation.
Related JoVE Video
Knockdown of N-acetylglucosaminyl transferase V ameliorates hepatotoxin-induced liver fibrosis in mice.
Toxicol. Sci.
PUBLISHED: 06-23-2013
Show Abstract
Hide Abstract
Aberrant N-glycosylation caused by altered N-acetyl glucosaminyltransferase V (GnT-V) expression is known to regulate tumor invasion and metastasis by modulating multiple cytokine signaling pathways. However, the exact role of GnT-V in the development of liver fibrosis has not been clearly defined. Here, we induced mouse liver fibrosis by ip injections of carbon tetrachloride (CCl4) or thioacetamide (TAA) and observed significant increase of hepatic GnT-V during the processes of liver fibrogenesis. Meanwhile, upregulations of GnT-V were detected in the activated hepatic stellate cells (HSCs) and injured hepatocytes. To knock down hepatic GnT-V expression, adenovirus that expressed the GnT-V siRNA was injected via the tail vein. Adenovirus-mediated delivery of GnT-V siRNA dramatically reduced the GnT-V expression in fibrotic liver and activated HSC in vivo and consequently alleviated CCl4- or TAA-induced liver fibrosis as assessed through collagen deposition and profiles of profibrogenic markers. Furthermore, knockdown of GnT-V in HSCs reduced transforming growth factor beta (TGF-?)/Smad signaling and blunted the activated HSC phenotype. The suppression of TGF-?/Smad signaling in HSCs correlated with the decrease of GnT-V-modified ?1,6-branched N-glycan on TGF-? receptors. Knockdown of GnT-V also suppressed platelet-derived growth factor (PDGF)-induced HSC proliferation and migration through inhibiting PDGF/Erk signaling. Finally, we demonstrated that knockdown of GnT-V profoundly suppressed TGF-?1-induced epithelial-mesenchymal transition (EMT) in hepatocytes by morphological assessment and reversal of EMT markers. In conclusion, this study demonstrates that GnT-V is implicated in hepatotoxin-induced liver fibrosis, and targeting GnT-V may be a feasible and promising approach for treating liver fibrosis.
Related JoVE Video
Gain-of-function mutations in SCN11A cause familial episodic pain.
Am. J. Hum. Genet.
PUBLISHED: 06-18-2013
Show Abstract
Hide Abstract
Many ion channel genes have been associated with human genetic pain disorders. Here we report two large Chinese families with autosomal-dominant episodic pain. We performed a genome-wide linkage scan with microsatellite markers after excluding mutations in three known genes (SCN9A, SCN10A, and TRPA1) that cause similar pain syndrome to our findings, and we mapped the genetic locus to a 7.81 Mb region on chromosome 3p22.3-p21.32. By using whole-exome sequencing followed by conventional Sanger sequencing, we identified two missense mutations in the gene encoding voltage-gated sodium channel Nav1.9 (SCN11A): c.673C>T (p.Arg225Cys) and c.2423C>G (p.Ala808Gly) (one in each family). Each mutation showed a perfect cosegregation with the pain phenotype in the corresponding family, and neither of them was detected in 1,021 normal individuals. Both missense mutations were predicted to change a highly conserved amino acid residue of the human Nav1.9 channel. We expressed the two SCN11A mutants in mouse dorsal root ganglion (DRG) neurons and showed that both mutations enhanced the channels electrical activities and induced hyperexcitablity of DRG neurons. Taken together, our results suggest that gain-of-function mutations in SCN11A can be causative of an autosomal-dominant episodic pain disorder.
Related JoVE Video
Crystal structure of the Golgi casein kinase.
Proc. Natl. Acad. Sci. U.S.A.
PUBLISHED: 06-10-2013
Show Abstract
Hide Abstract
The family with sequence similarity 20 (Fam20) kinases phosphorylate extracellular substrates and play important roles in biomineralization. Fam20C is the Golgi casein kinase that phosphorylates secretory pathway proteins within Ser-x-Glu/pSer motifs. Mutations in Fam20C cause Raine syndrome, an osteosclerotic bone dysplasia. Here we report the crystal structure of the Fam20C ortholog from Caenorhabditis elegans. The nucleotide-free and Mn/ADP-bound structures unveil an atypical protein kinase-like fold and highlight residues critical for activity. The position of the regulatory ?C helix and the lack of an activation loop indicate an architecture primed for efficient catalysis. Furthermore, several distinct elements, including the presence of disulfide bonds, suggest that the Fam20 family diverged early in the evolution of the protein kinase superfamily. Our results reinforce the structural diversity of protein kinases and have important implications for patients with disorders of biomineralization.
Related JoVE Video
Data processing and analysis of the imaging Thomson scattering diagnostic system on HT-7 tokamak.
Rev Sci Instrum
PUBLISHED: 06-08-2013
Show Abstract
Hide Abstract
A high spatial resolution imaging Thomson scattering diagnostic system was developed in ASIPP (Institute of Plasma Physics, Chinese Academy of Sciences). After about one month trial running on the superconducting HT-7 (Hefei Tokamak-7) tokamak, the system was proved to be capable of measuring plasma electron temperature. The system setup and data calibration are described in this paper and then the instrument function is studied in detail, as well as the measurement capability, an electron temperature of 50 eV to 2 keV and density beyond 1 × 10(19) m(-3). Finally, the data processing method and experimental results are presented.
Related JoVE Video
An Efficient Antiviral Strategy for Targeting Hepatitis B Virus Genome Using Transcription Activator-Like Effector Nucleases.
Mol. Ther.
PUBLISHED: 06-05-2013
Show Abstract
Hide Abstract
The hepatitis B virus (HBV) is a DNA virus that can cause chronic hepatitis B (CHB) in humans. Current therapies for CHB infection are limited in efficacy and do not target the pre-existing viral genomic DNA, which are present in the nucleus as a covalently closed circular DNA (cccDNA) form. The transcription activator-like (TAL) effector nucleases (TALENs) are newly developed enzymes that can cleave sequence-specific DNA targets. Here, TALENs targeting the conserved regions of the viral genomic DNA among different HBV genotypes were constructed. The expression of TALENs in Huh7 cells transfected with monomeric linear full-length HBV DNA significantly reduced the viral production of HBeAg, HBsAg, HBcAg, and pgRNA, resulted in a decreased cccDNA level and misrepaired cccDNAs without apparent cytotoxic effects. The anti-HBV effect of TALENs was further demonstrated in a hydrodynamic injection-based mouse model. In addition, an enhanced antiviral effect with combinations of TALENs and interferon-? (IFN-?) treatment was observed and expression of TALENs restored HBV suppressed IFN-stimulated response element-directed transcription. Taken together, these data indicate that TALENs can specifically target and successfully inactivate the HBV genome and are potently synergistic with IFN-?, thus providing a potential therapeutic strategy for treating CHB infection.Molecular Therapy (2013); doi:10.1038/mt.2013.212.
Related JoVE Video
3-hydroxybutyrate methyl ester as a potential drug against Alzheimers disease via mitochondria protection mechanism.
Biomaterials
PUBLISHED: 05-30-2013
Show Abstract
Hide Abstract
Alzheimers disease (AD) is induced by many reasons, including decreased cellular utilization of glucose and brain cell mitochondrial damages. Degradation product of microbially synthesized polyhydroxybutyrate (PHB), namely, 3-hydroxybutyrate (3HB), can be an alternative to glucose during sustained hypoglycemia. In this study, the derivative of 3HB, 3-hydroxybutyrate methyl ester (HBME), was used by cells as an alternative to glucose. HBME inhibited cell apoptosis under glucose deprivation, rescued activities of mitochondrial respiratory chain complexes that were impaired in AD patients and decreased the generation of ROS. Meanwhile, HBME stabilized the mitochondrial membrane potential. In vivo studies showed that HBME crossed the blood brain barrier easier compared with charged 3HB, resulting in a better bioavailability. AD mice treated with HBME performed significantly better (p < 0.05) in the Morris water maze compared with other groups, demonstrating that HBME has a positive in vivo pharmaceutical effect to improve the spatial learning and working memory of mice. A reduced amyloid-? deposition in mouse brains after intragastric administration of HBME was also observed. Combined with the in vitro and in vivo results, HBME was proposed to be a drug candidate against AD, its working mechanism appeared to be mediated by various effects of protecting mitochondrial damages.
Related JoVE Video
Study of cell apoptosis in the hippocampus and thalamencephalon in a ventricular fluid impact model.
Exp Ther Med
PUBLISHED: 05-25-2013
Show Abstract
Hide Abstract
The aim of this study was to investigate the apoptosis of nerve cells in the hippocampal and thalamencephalon regions using a rabbit model of ventricular fluid impact. The results for the study demonstrated a variety of pathophysiological changes in the rabbit model, while changes in the hippocampal and thalamencephalon regions were observed under a light microscope following hematoxylin and eosin (H&E)/terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) staining. Among the mild, moderate and severe injury groups, there were significant differences in the mortality rate and in the changes in vital signs and consciousness recovery time following trauma. Furthermore, H&E staining showed that pathological changes, such as hemorrhage and necrosis, occurred in the hippocampal and thalamencephalon regions at an early stage subsequent to trauma, while TUNEL staining showed that neuronal apoptosis occurred in the various injury groups. In traumatic brain injuries, the impact caused by cerebrospinal fluid moving with a certain energy results in marked damage to the contralateral periventricular structures and may generate a series of pathophysiological changes.
Related JoVE Video
Rapid preparation of pH-sensitive polymeric nanoparticle with high loading capacity using electrospray for oral drug delivery.
Mater Sci Eng C Mater Biol Appl
PUBLISHED: 05-21-2013
Show Abstract
Hide Abstract
Drug loading capacity is an important property for an ideal drug delivery system. However, the drug loading capacity of prepared pH-sensitive polymeric nanoparticles is usually low. To overcome this drawback, the electrospray method was used to prepare Eudragit L 100-55 nanoparticles with high drug loading capacity in one step. Omeprazole was selected as the model drug. The maximum loading capacity of nanoparticles was 43.21% by changing the mass ratio of drug to polymer, and the entrapment efficiency was nearly 100%. The prepared nanoparticle showed spherical or ellipsoidal morphology and the average diameter was about 300 nm. The pH-sensitive nanoparticle displayed pH-dependent release in vitro. In addition, a slight cytotoxicity was detected in the cytotoxicity study. The results indicated that electrospray is an easy, rapid and efficient technique for the preparation of high-loading pH-sensitive polymeric nanoparticles, and the pH-sensitive nanoparticle is a promising carrier for oral drug delivery.
Related JoVE Video
Identification and expression of a novel MDM4 splice variant in human glioma.
Brain Res.
PUBLISHED: 05-15-2013
Show Abstract
Hide Abstract
The product of the MDMX (or MDM4) gene is structurally related to the MDM2 oncoprotein and is also capable of interacting with the tumor suppressor protein p53. The MDM4 gene is overexpressed in several human tumors, while its product can be detected as various isoforms. This study was aimed to find the presence of aberrant mRNA transcripts of MDM4 in human glioma and their association with the clinicopathological characteristics of glioma patients. 42 glioma tissues were examined for MDM4 mRNA splicing variants by RT-PCR. A total of four distinct transcript sizes (full length-MDM4 851 bp, MDM4-S 783 bp, MDM4-A 701 bp, MDM4-B 540 bp) were detected. In the present study, we first report the novel alternative splicing form of MDM4, MDM4-B (GenBank accession no.KC479043.1). Expression of MDM4-B was present in various stages of human gliomas, but no significant correlation between presence of MDM4-B and malignancy of glioma was observed. The expression level of MDM4-B mRNA detected by real-time PCR was not only significantly associated with tumor stages, but also with p53 mutation and Ki-67 status which are important clinical molecular markers of glioma. Our data indicate that the novel variant MDM4-B may play a role in glioma tumorigenesis or cancer progression.
Related JoVE Video
Biopolymer-activated graphitic carbon nitride towards a sustainable photocathode material.
Sci Rep
PUBLISHED: 05-13-2013
Show Abstract
Hide Abstract
Photoelectrochemical (PEC) conversion of solar light into chemical fuels is one of the most promising solutions to the challenge of sustainable energy. Graphitic carbon (IV) nitride polymer (g-CN) is an interesting sustainable photocathode material due to low-cost, visible-light sensitivity, and chemical stability up to 500 °C in air. However, grain boundary effects and limited active sites greatly hamper g-CN activity. Here, we demonstrate biopolymer-activation of g-CN through simultaneous soft-templating of a sponge-like structure and incorporation of active carbon-dopant sites. This facile approach results in an almost 300% increase in the cathodic PEC activity of g-CN under simulated solar-irradiation.
Related JoVE Video
A near-infrared and ratiometric fluorescent chemosensor for palladium.
Analyst
PUBLISHED: 05-09-2013
Show Abstract
Hide Abstract
A near-infrared chemosensor for palladium based on the Tsuji-Trost reaction was developed. It displayed specific and ratiometric fluorescent responses toward palladium with a distinct color change from green to blue in aqueous media. PEG400 was employed as the reducing agent and palladium ligand instead of water-insoluble triphenylphosphine. The chemosensors bioimaging potential was demonstrated by in vitro and in vivo experiments.
Related JoVE Video
Screening ?-glucosidase inhibitor from natural products by capillary electrophoresis with immobilised enzyme onto polymer monolith modified by gold nanoparticles.
Food Chem
PUBLISHED: 04-23-2013
Show Abstract
Hide Abstract
A novel strategy for screening ?-glucosidase inhibitors (AGIs) from natural products by capillary electrophoresis (CE) with an immobilised enzyme microreactor was developed. In this approach, gold nanoparticles (AuNPs) was first covalently attached to surface of the pores of the porous polymer capillary monolith via the formation of an Au-S bond, and ?-glucosidase was then simply and stably immobilised onto AuNPs through the strong affinity of gold for amino groups of the enzyme. In order to profiling the activity of the immobilised ?-glucosidase, the natural substrate was hydrolyzed by it and the yield of product was determined by CE. The amount of covalently attached ?-glucosidase to the monolith was calculated to be about 30.0 ?g/mg. The immobilised enzyme exhibited 80% activity after 25 runs, and only lost 7.6% of activity after 6 runs within 31 days. Screening of AGIs present in extracts of natural products by the proposed method was demonstrated.
Related JoVE Video
An integrative approach for the large-scale identification of human genome kinases regulating cancer metastasis.
Nanomedicine
PUBLISHED: 04-19-2013
Show Abstract
Hide Abstract
Kinases become one of important groups of drug targets. To identify more kinases being potential for cancer therapy, we developed an integrative approach for the large-scale screen of functional genes capable of regulating the main traits of cancer metastasis. We first employed self-assembled cell microarray to screen functional genes that regulate cancer cell migration using a human genome kinase siRNA library. We identified 81 genes capable of significantly regulating cancer cell migration. Following with invasion assays and bio-informatics analysis, we discovered that 16 genes with differentially expression in cancer samples can regulate both cell migration and invasion, among which 10 genes have been well known to play critical roles in the cancer development. The remaining 6 genes were experimentally validated to have the capacities of regulating cell proliferation, apoptosis and anoikis activities besides cell motility. Together, these findings provide a new insight into the therapeutic use of human kinases.
Related JoVE Video
Luminol electrochemiluminescence for the analysis of active cholesterol at the plasma membrane in single mammalian cells.
Anal. Chem.
PUBLISHED: 04-04-2013
Show Abstract
Hide Abstract
A luminol electrochemiluminescence assay was reported to analyze active cholesterol at the plasma membrane in single mammalian cells. The cellular membrane cholesterol was activated by the exposure of the cells to low ionic strength buffer or the inhibition of intracellular acyl-coA/cholesterol acyltransferase (ACAT). The active membrane cholesterol was reacted with cholesterol oxidase in the solution to generate a peak concentration of hydrogen peroxide on the electrode surface, which induced a measurable luminol electrochemiluminescence. Further treatment of the active cells with mevastatin decreased the active membrane cholesterol resulting in a drop in luminance. No change in the intracellular calcium was observed in the presence of luminol and voltage, which indicated that our analysis process might not interrupt the intracellular cholesterol trafficking. Single cell analysis was performed by placing a pinhole below the electrode so that only one cell was exposed to the photomultiplier tube (PMT). Twelve single cells were analyzed individually, and a large deviation on luminance ratio observed exhibited the cell heterogeneity on the active membrane cholesterol. The smaller deviation on ACAT/HMGCoA inhibited cells than ACAT inhibited cells suggested different inhibition efficiency for sandoz 58035 and mevastatin. The new information obtained from single cell analysis might provide a new insight on the study of intracellular cholesterol trafficking.
Related JoVE Video
Ecotoxicological effects of copper and selenium combined pollution on soil enzyme activities in planted and unplanted soils.
Environ. Toxicol. Chem.
PUBLISHED: 04-02-2013
Show Abstract
Hide Abstract
The present study explored the joint effects of Cu and Se pollution mechanisms on soil enzymes to provide references for the phytoremediation of contaminated areas and agricultural environmental protection. Pot experiments and laboratory analyses were carried out to study the individual and combined influences of Cu and Se on soil enzyme activities. The activities of four soil enzymes (urease, catalase, alkaline phosphatase, and nitrate reductase) were chosen. All soil enzyme activities tested were inhibited by Cu and Se pollution, either individually or combined, in varying degrees, following the order nitrate reductase>urease>catalase>alkaline phosphatase. Growing plants stimulated soil enzyme activity in a similar trend compared with treatments without plants. The joint effects of Cu and Se on catalase activity showed synergism at low concentrations and antagonism at high concentrations, whereas the opposite was observed for urease activity. However, nitrate reductase activity showed synergism both with and without plant treatments. The half maximal effective concentration (EC50) of exchangeable fractions had a similar trend with the EC50 of total content and was lower than that of total content. The EC50 values of nitrate reductase and urease activities were significantly lower for both Se and Cu (p<0.05), which indicated that they were more sensitive than the other two enzymes.
Related JoVE Video
Molecular sensitized GdF3:Eu3+ for color tuning and highly enhanced luminescent properties.
J Colloid Interface Sci
PUBLISHED: 03-21-2013
Show Abstract
Hide Abstract
In this work, we report on the preparation of [2,3-f]pyrazino[1,10]phenanthroline-2,3-dicarboxylic anions (PPDB(2-)) modified GdF3:Eu(3+) nanocrystals by a versatile ligand exchange approach for highly enhanced luminescent properties. The samples were carefully characterized by X-ray powder diffraction, transmission electron microscopy, infrared spectra and photoluminescence. It is found that all GdF3:Eu(3+) nanoparticles were entirely composed of homogeneous nano-spheres with an average diameter of about 30-35 nm. After PPDB(2-) capping, GdF3:Eu(3+) nanocrystals exhibited higher color purity and shorter lifetime time, which can be well recognized as a consequence of surface structure modification and local symmetry alteration near Eu(3+) ions. High color purity and short lifetime of PPDB(2-) modified GdF3:Eu(3+) nanocrystals predict highly enhanced red luminescence, which showed the quantum efficiency of ~34%. The highly enhanced luminescent property enables its potential application as chemosensor for detection of heavy metal ions.
Related JoVE Video
A p-type Cr-doped TiO2 photo-electrode for photo-reduction.
Chem. Commun. (Camb.)
PUBLISHED: 03-18-2013
Show Abstract
Hide Abstract
A p-type Cr-doped TiO2 photo-electrode is fabricated using a pulsed laser deposition method on a Sn doped indium-oxide-coated glass sheet (ITO). The p-type properties of the as-prepared Cr-doped TiO2 photo-electrode are suggested to be attributed to unique substitutional Cr(4+) doping in the TiO2 lattice.
Related JoVE Video
Study about correlation of anti-neutrophil cytoplasmic antibodies and anticardiolipin antibodies with thromboangiitis obliterans.
Vascular
PUBLISHED: 03-16-2013
Show Abstract
Hide Abstract
Doctors often have difficulties in clinical diagnosis and clinical stage of thromboangiitis obliterans (TAO). Immunolesion was important in the initiation and progression of various kinds of vasculitis diseases, including TAO. Several kinds of immune complexes were developed by immunolesion, including anti-neutrophil cytoplasmic antibodies (ANCA) and anticardiolipin antibodies (ACA). Our aim was to determine if it is an effective way for clinical diagnosis and clinical stage of TAO by detection of the presence of ANCA and ACA in blood serum of patients with TAO and the relationship among the presence of ANCA, ACA and patients with different grades of TAO. Blood samples and clinical characteristics were collected from 38 patients with Rutherford grade I TAO, 30 patients with Rutherford grade II-III TAO, 75 patients with arteriosclerosis obliterans (ASO) and 65 healthy volunteers. Their serum samples were investigated for ANCA by indirect immunofluorescent (IIF), and for ACA and ANCA specificity antigens including reactivity to proteinase 3(PR3), myeloperoxidase (MPO), cathepsin G (CG), bactericidal/permesbility-increasing protein (BPI), elastase (HLE) and lactoferrin (LF) by enzyme linked immunosorbent assay (ELISA). (1) ANCA positive rate and titre were much higher in cases with Rutherford grade I TAO (52.6%, 20/38, 0.386 ± 0.458) and Rutherford grade II-III TAO (73.3%, 22/30, 0.847 ± 0.658) than those in cases with ASO (4%, 3/75, 0.011 ± 0.002) and healthy volunteers (0%,0/65, 0.010 ± 0.002) (P < 0.01). ANCA positive rate and titre were higher in cases with Rutherford grade II-III TAO (73.3%, 22/30, 0.847 ± 0.658) than those in cases with Rutherford grade I TAO (52.6%, 20/38, 0.386 ± 0.458) (P < 0.05). (2) ACA concentration was much higher in cases with Rutherford grade I TAO (270.13 ± 13.05 IU/mL) and Rutherford grade II-III TAO (279.33 ± 19.98 IU/mL) than that in cases with ASO (236.85 ± 17.32 IU/mL) and healthy volunteers (229.16 ± 15.55 IU/mL) (P < 0.05) respectively. (3) In 42 cases of ANCA-positive samples, there were 20 cases reacted with MPO, 14 cases reacted with LF, five cases reacted with HLE, five cases reacted with BPI and no one reacted with PR3 and CG. All cases were Rutherford grade II-III TAO. Our results indicate that ANCA, ANCA specificity antigens and ACA were detected susceptibly and availably in patients with TAO. Thus, detection of ANCA, ANCA specificity antigens and ACA was helpful for clinical diagnosis of TAO and detection of ANCA and ANCA specificity antigens was helpful for clinical staging of TAO. They are important assistance for clinical diagnosis and stage of TAO.
Related JoVE Video
Industrial sector-based volatile organic compound (VOC) source profiles measured in manufacturing facilities in the Pearl River Delta, China.
Sci. Total Environ.
PUBLISHED: 03-12-2013
Show Abstract
Hide Abstract
Industrial sector-based VOC source profiles are reported for the Pearl River Delta (PRD) region, China, based source samples (stack emissions and fugitive emissions) analyzed from sources operating under normal conditions. The industrial sectors considered are printing (letterpress, offset and gravure printing processes), wood furniture coating, shoemaking, paint manufacturing and metal surface coating. More than 250 VOC species were detected following US EPA methods TO-14 and TO-15. The results indicated that benzene and toluene were the major species associated with letterpress printing, while ethyl acetate and isopropyl alcohol were the most abundant compounds of other two printing processes. Acetone and 2-butanone were the major species observed in the shoemaking sector. The source profile patterns were found to be similar for the paint manufacturing, wood furniture coating, and metal surface coating sectors, with aromatics being the most abundant group and oxygenated VOCs (OVOCs) as the second largest contributor in the profiles. While OVOCs were one of the most significant VOC groups detected in these five industrial sectors in the PRD region, they have not been reported in most other source profile studies. Such comparisons with other studies show that there are differences in source profiles for different regions or countries, indicating the importance of developing local source profiles.
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.