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Find video protocols related to scientific articles indexed in Pubmed.
Enhanced performance of InGaN-based light emitting diodes through a special etch and regrown process in n-GaN layer.
Opt Express
PUBLISHED: 10-17-2014
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We reported that the peak efficiency together with the efficiency droop in InGaN-based light emitting diodes could be effectively modified through a simple and low-cost etch-regrown process in n-GaN layer. The etched n-GaN template contained pyramid arrays with inclined side planes. The following lateral overgrowth process from the etched n-GaN template substantially reduced the edge dislocation density and residential compressive strain in epilayers. The efficiency droop of LED samples thus could be modified due to the reduced polarization field, resulting from the strain relaxation in epilayers. What is more, the peak efficiency and reverse current leakage were also modified due to the reduction of dislocations.
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Elevated circulating lipocalin-2 levels independently predict incident cardiovascular events in men in a population-based cohort.
Arterioscler. Thromb. Vasc. Biol.
PUBLISHED: 09-04-2014
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Adipose tissue inflammation and perturbation of adipokine secretion may contribute to the pathogenesis of cardiovascular diseases (CVD). Lipocalin-2 (LCN2), mainly released from adipocytes, has been shown to be positively associated with CVD in cross-sectional studies. We aimed to evaluate the association of LCN2 with CVD involving a population-based cohort recruited from the Shanghai Diabetes Study.
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Cigarette smoking and the risk of pancreatic cancer: a case-control study.
Med. Oncol.
PUBLISHED: 08-27-2014
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We proposed to investigate the relationship between smoking and pancreatic cancer. From February 2000 to February 2010, we conducted a hospital-based case-control study on pancreatic cancer. Information was collected by questionnaire. Cases were 307 patients with pancreatic cancer, 1,228 were healthy matched controls. Multiple logistic regression was used to estimate the odds ratios (OR) and the corresponding 95% confidence intervals (CI). Compared to never smokers, current smokers had a significantly increased risk of pancreatic cancer, OR 1.71 (95% CI 1.25-2.35). Among smokers, a significant association with higher smoking intensity was shown (?20 cigarettes/day: OR=2.18; 95% CI 1.66-3.69). A significantly decreasing trend in risk with increasing years after smoking cessation was observed (p<0.01). The ORs were 0.73 (95% CI 0.38-1.33) and 0.46 (95% CI 0.21-0.94) for those who had quit smoking for <10 and ?10 years, respectively. Our case-control study confirmed that cigarette smoking was associated with an increased risk of death from pancreatic cancer.
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Simultaneous determination of the content of isoquinoline alkaloids in Dicranostigma leptopodum (Maxim) Fedde and the effective fractionation of the alkaloids by high-performance liquid chromatography with diode array detection.
J Sep Sci
PUBLISHED: 08-19-2014
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A simple and efficient method was developed for the simultaneous determination of eight isoquinoline alkaloids in methanol extracts of Dicranostigma leptopodum (Maxim) Fedde and the effective fractionation of the alkaloids of D. leptopodum by high-performance liquid chromatography with diode array detection. The chromatographic conditions were optimized on a SinoChrom ODS-BP column to obtain a good separation of the four types of alkaloid analytes, including two aporphines (isocorydine, corydine), two protopines (protopine and allocryptopine), a morphine (sinoacutine), and three quaternary protoberberine alkaloids (berberrubine, 5-hydroxycoptisine, and berberine). The separation of these alkaloids was significantly affected by the composition of the mobile phase, and particularly by its pH value. Acetonitrile (A) and 0.2% phosphoric acid solution adjusted to pH 6.32 with triethylamine (B) were selected as the mobile phase with a gradient elution. With this method, a new quaternary protoberberine alkaloid was isolated and the two structural isomers (isocorydine and corydine) were baseline separated. The appropriate harvest period for D. leptopodum was also recommended based on our analysis. The method for the effective fraction of the alkaloids of D. leptopodum was optimized under this method with regard to the varying significant pharmacological activities of the alkaloids.
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Isocorydine derivatives and their anticancer activities.
Molecules
PUBLISHED: 08-12-2014
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In order to improve the anticancer activity of isocorydine (ICD), ten isocorydine derivatives were prepared through chemical structure modifications, and their in vitro and in vivo activities were experimentally investigated. 8-Amino-isocorydine (8) and 6a,7-dihydrogen-isocorydione (10) could inhibit the growth of human lung (A549), gastric (SGC7901) and liver (HepG2) cancer cell lines in vitro. Isocorydione (2) could inhibit the tumor growth of murine sarcoma S180-bearing mice, and 8-acetamino-isocorydine (11), a pro-drug of 8-amino-isocorydine (8), which is instable in water solution at room temperature, had a good inhibitory effect on murine hepatoma H22-induced tumors. The results suggested that the isocorydine structural modifications at C-8 could significantly improve the biological activity of this alkaloid, indicating its suitability as a lead compound in the development of an effective anticancer agent.
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Efficiency enhancement of homoepitaxial InGaN/GaN light-emitting diodes on free-standing GaN substrate with double embedded SiO2 photonic crystals.
Opt Express
PUBLISHED: 07-01-2014
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Homoepitaxially grown InGaN/GaN light emitting diodes (LEDs) with SiO2 nanodisks embedded in n-GaN and p-GaN as photonic crystal (PhC) structures by nanospherical-lens photolithography are presented and investigated. The introduction of SiO2 nanodisks doesn't produce the new dislocations and doesn't also result in the electrical deterioration of PhC LEDs. The light output power of homoepitaxial LEDs with embedded PhC and double PhC at 350 mA current is increased by 29.9% and 47.2%, respectively, compared to that without PhC. The corresponding light radiation patterns in PhC LEDs on GaN substrate show a narrow beam shape due to strong guided light extraction, with a view angle reduction of about 30°. The PhC LEDs are also analyzed in detail by finite-difference time-domain simulation (FDTD) to further reveal the emission characteristics.
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Efficiency improvement by polarization-reversed electron blocking structure in GaN-based Light-emitting diodes.
Opt Express
PUBLISHED: 06-13-2014
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Polarization-reversed electron-blocking structure, which had negative polarization charges localized at the interface between the last quantum barrier (LQB) and electron-blocking layer (EBL), was demonstrated to remarkably improve the light-emitting efficiency of GaN-based blue light-emitting diodes (LEDs) numerically and experimentally. The improvement was attributed to the enhanced electron-blocking effectiveness by the elevated conduction band nearby the LQB/EBL interface. Nevertheless, the efficiency droop was not mitigated because the decrease of electron-leakage was accompanied by the increase of Auger recombination.
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Optical properties of nanopillar AlGaN/GaN MQWs for ultraviolet light-emitting diodes.
Opt Express
PUBLISHED: 06-13-2014
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Nanopillar AlGaN/GaN multiple quantum wells ultraviolet light-emitting diodes (LEDs) were fabricated by nanosphere lithography and dry-etching. The optical properties of the nanopillar LEDs were characterized by both temperature-dependent and time-resolved photoluminescence measurements. Compared to an as-grown sample, the nanopillar sample has a PL emission peak blue-shift of 7 meV, a 42% enhanced internal quantum efficiency at room temperature and a reduced radiative recombination lifetime from 870 picosecond to 621 picosecond at 7K. These results are directly from the suppressed quantum confined stark effect that is due to the strain relaxation in the nanopillar MQWs, further revealed by micro-Raman measurement. Additionally, finite-difference time domain simulation also proves better light extraction efficiency in the nanopillar LEDs.
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Modulation of neointimal lesion formation by endogenous androgens is independent of vascular androgen receptor.
Cardiovasc. Res.
PUBLISHED: 06-04-2014
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Low androgen levels have been linked with an increased risk of cardiovascular disease in men. Previous studies have suggested that androgens directly inhibit atherosclerotic lesion formation although the underlying mechanisms for this remain unclear. This study addressed the hypothesis that endogenous androgens inhibit arterial remodelling by a direct action on the androgen receptor (AR) in the vascular wall.
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The identification of six novel proteins with fibronectin or collagen type I binding activity from Streptococcus suis serotype 2.
J. Microbiol.
PUBLISHED: 05-27-2014
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Streptococcus suis, a major swine pathogen, is an emerging zoonotic agent that causes meningitis and septic shock. Bacterial cell wall and secreted proteins are often involved in interactions with extracellular matrix proteins (ECMs), which play important roles in the initial steps of pathogenesis. In this study, 2D SDS-PAGE, western blotting-based binding affinity measurements, and microtiter plate binding assays were used to identify cell wall and secreted proteins from S. suis that interact with fibronectin and collagen type I. We identified six proteins from S. suis, including three proteins (translation elongation factor G, oligopeptide-binding protein OppA precursor, and phosphoglycerate mutase) that show both fibronectin and collagen type I binding activity. To the best of our knowledge, these three newly identified proteins had no previously reported fibronectin or collagen type I binding activity. Overall, the aim in this study was to identify proteins with ECM binding activity from S. suis and it represents the first report of six new proteins from S. suis that interact with fibronectin or collagen type I.
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Nipple discharge of CA15-3, CA125, CEA and TSGF as a new biomarker panel for breast cancer.
Int J Mol Sci
PUBLISHED: 05-14-2014
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Breast cancer is the second leading cause of cancer death in women. Serum biomarkers such as cancer antigen 15-3 (CA15-3), cancer antigen 125 (CA125), and carcinoembryonic antigen (CEA) can be used as diagnostic and prognostic factors and can also provide valuable information during follow-up. However, serum protein biomarkers show limited diagnostic sensitivity and specificity in stand-alone assays because their levels reflect tumor burden. To validate whether biomarkers in nipple discharge may serve as novel biomarkers for breast cancer, we composed a panel of potential cancer biomarkers, including CA15-3, CA125, CEA, and malignant tumor-specific growth factor (TSGF), and evaluated their expression in both serum and nipple discharge in order to explore the expression and significance of estrogen receptor (ER), progestrone receptor (PR), epidermal growth factor receptor type 2 (HER2/neu), CA15-3, CA125, CEA, and TSGF expression for their combined predictive value for breast cancer and in judging the prognosis of breast cancer. Univariate analysis revealed that combined detection of CA15-3, CA125, CEA, and TSGF in nipple discharge served as novel biomarkers for the diagnosis and prognosis of breast cancer, but in the multivariate analyses the adverse effects of the four biomarkers combination in nipple discharge positivity on overall survival were lost. Multivariate analysis revealed that the positivity of the combined detection of the four biomarkers in both nipple discharge and serum was significantly higher than that of other detection methods. Thus, the combined detection of these four biomarkers both in serum and nipple discharge was retained as an independent prognostic variable in breast cancer patients. Our results indicate that CA15-3, CA125, CEA, and TSGF in nipple discharge can serve as novel biomarkers in the diagnosis and prognosis of breast cancer.
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Overexpression of syntenin enhances hepatoma cell proliferation and invasion: Potential roles in human hepatoma.
Oncol. Rep.
PUBLISHED: 05-13-2014
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Hepatocellular carcinoma (HCC) ranks as the third leading cause of tumor-related mortality worldwide. Recently, syntenin was found to be upregulated in several tumors and to exert pivotal roles in the development of cancer. However, its function and the underlying mechanism in HCC remain to be defined. In the present study, the elevated expression levels of syntenin mRNA and protein were detected in four HCC cell lines. Overexpression of syntenin in hepatoma HCCLM3 cells enhanced cell proliferation. Furthermore, syntenin upregulation increased epidermal growth factor receptor (EGFR) expression, which accounted for syntenin?induced cell proliferation as precondition with EGFR siRNA clearly attenuated cell proliferation in syntenin-transfected cells. At the same time, syntenin overexpression promoted cell invasion by MMP-2, as pretreatment with anti-MMP-2 antibody blocked syntenin-induced invading cell numbers. Additionally, syntenin upregulation induced the phosphorylation of p38 MAPK contributing to the increase in MMP-2 expression, as treatment with the specific inhibitor for p38 MAPK (SB203580) clearly abrogated MMP-2 expression induced by syntenin. Collectively, our results suggest that syntenin overexpression plays a critical role in promoting the proliferation and invasion of hepatoma cells. Therefore, the present study provides new insight into how syntenin accelerates the development and progression of hepatoma, and suggests that syntenin may be a promising therapeutic agent against hepatoma.
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Identification of helicity-dependent photocurrents from topological surface states in Bi2Se3 gated by ionic liquid.
Sci Rep
PUBLISHED: 04-16-2014
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Dirac-like surface states on surfaces of topological insulators have a chiral spin structure with spin locked to momentum, which is interesting in physics and may also have important applications in spintronics. In this work, by measuring the tunable helicity-dependent photocurrent (HDP), we present an identification of the HDP from the Dirac-like surface states at room temperature. It turns out that the total HDP has two components, one from the Dirac-like surface states, and the other from the surface accumulation layer. These two components have opposite directions. The clear gate tuning of the electron density as well as the HDP signal indicates that the surface band bending and resulted surface accumulation are successfully modulated by the applied ionic liquid gate, which provides a promising way to the study of the Dirac-like surface states and also potential applications in spintronic devices.
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[The effects of a very low carbohydrate diet intervention on improving cardiovascular risk factors in obese subjects].
Zhonghua Nei Ke Za Zhi
PUBLISHED: 03-29-2014
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To investigate the effects of a very low carbohydrate diet (VLCD) on improving cardiovascular risk factors in obese individuals.
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Efficiency improvement and droop behavior in nanospherical-lens lithographically patterned bottom and top photonic crystal InGaN/GaN light-emitting diodes.
Opt Lett
PUBLISHED: 02-25-2014
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Large-scale SiO2 nanodisk arrays fabricated by nanospherical-lens lithography are embedded in the n-GaN and p-GaN layer of an InGaN/GaN light-emitting diode (LED) to produce photonic crystal (PC) structures for efficiency improvement. Following the obvious reduction of view angle, the light output power of bottom, top, and double PC LEDs is enhanced by 74.5%, 60.1%, and 88.2% compared to that of a conventional LED at 350 mA current, respectively. Despite the enhanced external quantum efficiency due to improved crystalline quality and light extraction, these PC LEDs exhibit lower peak efficiency current density and more serious efficiency droop than conventional LEDs. Combined with the rate equation, the droop mechanisms of PC LEDs have also been investigated experimentally and by simulation.
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Efficacy and tolerability of antidepressants in the treatment of adolescents and young adults with depression and substance use disorders: a systematic review and meta-analysis.
Addiction
PUBLISHED: 02-23-2014
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To measure the effectiveness of antidepressants for adolescents and young adults with co-occurring depression and substance use disorder.
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HUM calculator and HUM package for R: easy-to-use software tools for multicategory receiver operating characteristic analysis.
Bioinformatics
PUBLISHED: 02-10-2014
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Receiver operating characteristic (ROC) analysis is usually applied in bioinformatics to evaluate the abilities of biological markers to differentiate between the presence or absence of a disease. It includes the derivation of the useful scalar performance measure area under the ROC curve for binary classification tasks. As real applications often deal with more than two classes, multicategory ROC analysis and the corresponding hypervolume under the manifold (HUM) measure have become a topic of growing interest. To support researchers in carrying out multicategory ROC analysis, we have developed two tools in different programming environments which feature user-friendly, object-oriented and flexible interfaces and enable the user to compute HUM values and plot 2D- and 3D-ROC curves.
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miR-451: potential role as tumor suppressor of human hepatoma cell growth and invasion.
Int. J. Oncol.
PUBLISHED: 02-04-2014
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Malignant hepatoma is the leading cause of morbidity and mortality in primary liver cancer. MicroRNAs are widely accepted to act as tumor regulators to mediate tumorigenesis. Recently, miRNA-451 (miR-451) has attracted increasing attention due to its critical roles in the development of several types of cancers. Unfortunately, its function and underlying mechanism(s) of action in hepatoma remain unclear. In this study, a significant downregulation of miR-451 was observed in hepatoma cell lines. Its overexpression by administration of miR-451 mimics decreased cell viability and promoted cell apoptosis, indicating a critical role of miR-451 in cell growth. Further mechanistic analysis suggested that miR-451 overexpression accelerated cell death in a caspase-3-dependent manner, as pretreatment with its inhibitor z-VAD-fmk notably attenuated miR-451-induced cell apoptotic rates. Moreover, miR-451 upregulation abrogated cell invasive ability, accompanied with the decrease of matrix metalloproteinase-9 (MMP-9) expression levels, which may contribute to miR-451-triggered cell apoptosis. Taken together, these results reveal a prominent role of miR-451 as a tumor suppressor regulating hepatoma cell growth and invasion in a caspase-3- and MMP-9-dependent manner. Thus, our research supports this promising therapeutic agent against hepatoma.
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Spin transport study in a Rashba spin-orbit coupling system.
Sci Rep
PUBLISHED: 01-23-2014
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One of the most important topics in spintronics is spin transport. In this work, spin transport properties of two-dimensional electron gas in Al(x)Ga(1-x)N/GaN heterostructure were studied by helicity-dependent photocurrent measurements at room temperature. Spin-related photocurrent was detected under normal incidence of a circularly polarized laser with a Gaussian distribution. On one hand, spin polarized electrons excited by the laser generate a diffusive spin polarization current, which leads to a vortex charge current as a result of anomalous circular photogalvanic effect. On the other hand, photo-induced spin polarized electrons driven by a longitudinal electric field give rise to a transverse current via anomalous Hall Effect. Both of these effects originated from the Rashba spin-orbit coupling. By analyzing spin-related photocurrent varied with laser position, the contributions of the two effects were differentiated and the ratio of the spin diffusion coefficient to photo-induced anomalous spin Hall mobility D(s)/?(s) = 0.08?V was extracted at room temperature.
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Size-controllable nanopyramids photonic crystal selectively grown on p-GaN for enhanced light-extraction of light-emitting diodes.
Opt Express
PUBLISHED: 10-24-2013
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Size-controllable p-GaN hexagonal nanopyramids (HnPs)-photonic crystal (PhC) structures were selectively grown on flat p-GaN layer for the elimination of total internal reflection of light-emitting diodes (LEDs). The LEDs with HnPs-PhC of 46.3% bottom fill factor (PhC lattice constant is 730 nm) showed an improved light output power by 99.9% at forward current of 350 mA compared to the reference LEDs with flat p-GaN layer. We confirmed the effect of HnPs-PhC with different bottom fill factors and the effect of nanopyramid-shaped and nanocolumn-shaped PhC on the light-extraction of LEDs was also investigated by using three-dimensional finite-difference time-domain simulations.
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Enhanced anisotropic effective g factors of an Al0.25Ga0.75N/GaN heterostructure based quantum point contact.
Nano Lett.
PUBLISHED: 10-01-2013
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Gate-defined quantum point contacts (QPCs) were fabricated with Al0.25Ga0.75N/GaN heterostructures grown by metal-organic chemical vapor deposition (MOCVD). In the transport study of the Zeeman effect, greatly enhanced effective g factors (g*) were obtained. The in-plane g* is found to be 5.5 ± 0.6, 4.8 ± 0.4, and 4.2 ± 0.4 for the first to the third subband, respectively. Similarly, the out-of-plane g* is 8.3 ± 0.6, 6.7 ± 0.7, and 5.1 ± 0.7. Increasing g* with the population of odd-numbered spin-splitted subbands are obtained at 14 T. This portion of increase is assumed to arise from the exchange interaction in one-dimensional systems. A careful analysis shows that not only the exchange interaction but the spin-orbit interaction (SOI) in the strongly confined QPC contributes to the enhancement and anisotropy of g* in different subbands. An approach to distinguish the respective contributions from the SOI and exchange interaction is therefore proposed.
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Impacts of dung combustion on the carbon cycle of alpine grassland of the north Tibetan plateau.
Environ Manage
PUBLISHED: 06-07-2013
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Alpine grassland of Tibet is a frangible ecosystem in terms of carbon (C) emission. Yak dung is an important resident energy with about 80 % of yak dung combusted for energy in the north Tibetan plateau. This paper investigated the impact of dung combustion on the C cycle of the alpine grassland ecosystem in north Tibet, China. During the growing season of 2011, from a field survey and household questionnaires, the main impacts of dung collection for fuel on the C cycle of the ecosystem were identified. (1) The C sequestration and storage capacity, including the dung-derived C stored in soil and C captured by vegetation, decreased. The net primary production decreased remarkably because of the reduction of dung returned to soil. (2) In a given period, more C was emitted to the atmosphere in the dung combustion situation than that in the dung returned to soil situation. (3) The energy grazing alpine meadow ecosystem changed into a net C source, and the net biome production of the ecosystem dropped to -15.18 g C/m2 year in the dung combustion situation, 42.95 g C/m2 year less than that in the dung returned situation. To reduce the CO2 emission derived from dung use, the proportion of dung combustion should be reduced and alternative renewable energy such as solar, wind, or hydro energy should be advocated, which is suitable for, and accessible to, the north Tibetan plateau.
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Structural and mechanistic bases of the anticancer activity of natural aporphinoid alkaloids.
Curr Top Med Chem
PUBLISHED: 06-06-2013
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Aporphinoid alkaloids, which encompass a large number of complicated structures, are an important group of natural products. The anticancer activity of aporphinoid alkaloids has become a hot pharmaceutical research area in recent years. Recent studies on the anticancer activity of these compounds are reviewed. The structure activity relationships (SARs) and anticancer mechanisms of aporphinoid alkaloids, as well as simple aporphine, oxoaporphine, dehydroaporphine and dimeric aporphine, have been summarized. The presence of a 1,2-methylenedioxy group and methylation of nitrogen are key features to the cytotoxicity of aporphinoid alkaloids. Oxidation and dehydrogenation of C7 could improve the anticancer activity. The contributions of chirality of hydrogen at C6a and the substitution pattern of other positions about aporphinoid alkaloids for anticancer activity remain unknown. Induced cancer cells apoptosis, prevention of cell proliferation, DNA topoisomerase inhibition, reducing the drug-resistant cellular side population (SP) or cancer stem cells (CSCs) and inhibition of epidermal growth factor receptor (EGFR) tyrosine kinase seem to play important roles in the molecular mechanisms of anticancer activity about aporphinoid alkaloids.
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Serum fibroblast growth factor 19 levels are decreased in Chinese subjects with impaired fasting glucose and inversely associated with fasting plasma glucose levels.
Diabetes Care
PUBLISHED: 04-29-2013
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Fibroblast growth factor 19 (FGF19), a hormone secreted from the small intestine, has recently been shown to stimulate glycogen synthesis and inhibit gluconeogenesis through insulin-independent pathways. This study investigated the change of FGF19 in prediabetes and newly diagnosed type 2 diabetes mellitus (T2DM) and explored the association of serum FGF19 levels with parameters of glucose metabolism in Chinese subjects.
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Loss of ?-arrestin2 mediates pancreatic-islet dysfunction in mice.
Biochem. Biophys. Res. Commun.
PUBLISHED: 04-12-2013
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Insulin resistance and defective insulin secretion are two major factors contributing to the pathogenesis of type 2 diabetes. ?-Arrestin2 is known to interact with numerous signaling molecules. Our previous study demonstrated that ?-arrestin2 regulates insulin sensitivity in both skeletal muscle and liver, yet its role in insulin secretion remains elusive. In this study, we found that ?-arrestin2 was abundantly expressed in mouse pancreatic beta cells, while its expression was significantly decreased in obese and diabetic mouse models. Hyperglycemic clamp study showed that the acute and late phase of insulin secretion were impaired in ?-arrestin2 knockout mice. Ex vivo study showed that ?-arrestin2 deficient pancreatic islets exhibited blunted glucose-stimulated insulin secretion. Further analysis demonstrated the number of docked insulin granules in ?-arrestin2 deficient islets was markedly decreased compared to wild-type islets, while insulin content and beta cell mass remained unchanged. Our study establishes a new role for ?-arrestin2 in beta-cell functions, and suggests that the down regulation of ?-arrestin2 may contribute to impaired insulin secretion in type 2 diabetes.
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miRNA-21 is dysregulated in response to vein grafting in multiple models and genetic ablation in mice attenuates neointima formation.
Eur. Heart J.
PUBLISHED: 03-25-2013
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The long-term failure of autologous saphenous vein bypass grafts due to neointimal thickening is a major clinical burden. Identifying novel strategies to prevent neointimal thickening is important. Thus, this study aimed to identify microRNAs (miRNAs) that are dysregulated during neointimal formation and determine their pathophysiological relevance following miRNA manipulation.
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Nitride-based micron-scale hexagonal pyramids array vertical light emitting diodes by N-polar wet etching.
Opt Express
PUBLISHED: 03-14-2013
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In this work, we reported the fabrication of nitride-based hexagonal pyramids array (HPA) vertical-injection light emitting diodes (V-LEDs) by N-polar wet etching. The performance of HPA V-LEDs devices was significantly improved with 30% higher internal quantum efficiency compared with conventional roughened broad area V-LEDs. The simulated extraction efficiency by finite difference time domain method was 20% higher than typical roughened V-LEDs. The reversed leakage current of HPA V-LEDs was reduced due to better crystal quality, which was confirmed by conductive atomic force microscopy measurement. Furthermore, the efficiency droop for HPA V-LEDs were substantially alleviated.
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Growth receptor binding protein 10 inhibits glucose-stimulated insulin release from pancreatic ?-cells associated with suppression of the insulin/insulin-like growth factor-1 signalling pathway.
Clin. Exp. Pharmacol. Physiol.
PUBLISHED: 03-02-2013
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Growth receptor binding protein 10 (Grb10) is an adaptor protein that interacts with the insulin receptor and insulin-like growth factor (IGF)-1 receptor. Overexpression of Grb10 in muscle cells and adipocytes inhibits insulin signalling, and transgenic mice overexpressing Grb10 exhibit impaired glucose tolerance. However, the roles of Grb10 in ?-cells remain unknown. The aim of the present study was to explore the effect of Grb10 on ?-cell function. The effects of Grb10 on glucose-stimulated insulin secretion (GSIS) and the insulin/IGF-1 signalling pathway were investigated in rat islets and/or dispersed islet cells with Grb10 overexpresion by adenovirus transfection. Protein expression was detected by western blot analysis. We found that Grb10 was expressed in both human and rat pancreas. Expression of Grb10 was increased in islets isolated from rats fed a high-fat plus high-sugar diet compared with islets isolated from rats fed normal chow diet, as well as in INS 832/13 cells exposed to high levels of glucose (20 mmol/L), palmitate (1 mmol/L) and interleukin-1? (50 U/mL). Overexpression of Grb10 in INS 832/13 cells or rat islets impaired GSIS compared with the respective control (all P < 0.05). Moreover, inhibition of GSIS by Grb10 overexpression was associated with a decrease in insulin- and IGF-1-induced Akt and extracellular signal-regulated kinase 1/2 phosphorylation. The results of the present study demonstrate that Grb10 is an important negative regulator of insulin/IGF-1 signalling in pancreatic ?-cells and a potential target to improve ?-cell function.
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Beneficial effects of an 8-week, very low carbohydrate diet intervention on obese subjects.
Evid Based Complement Alternat Med
PUBLISHED: 02-18-2013
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Aim. To investigate the effects of weight loss during an 8-week very low carbohydrate diet (VLCD) on improvement of metabolic parameters, adipose distribution and body composition, and insulin resistance and sensitivity in Chinese obese subjects. Methods. Fifty-three healthy obese volunteers were given an 8-week VLCD. The outcomes were changes in anthropometry, body composition, metabolic profile, abdominal fat distribution, liver fat percent (LFP), and insulin resistance and sensitivity. Results. A total of 46 (86.8%) obese subjects completed the study. The VLCD caused a weight loss of -8.7 ± 0.6?kg (mean?±?standard error (SE), P < 0.0001) combined with a significant improvement of metabolic profile. In both male and female, nonesterified fatty acid (NEFA) significantly decreased (-166.2 ± 47.6? ? mol/L, P = 0.001) and ? -hydroxybutyric acid (BHA) increased (0.15 ± 0.06?mmol/L, P = 0.004) after eight weeks of VLCD intervention. The significant reductions in subcutaneous fat area (SFA), visceral fat area (VFA), and LFP were -66.5 ± 7.9?cm(2), -35.3 ± 3.9?cm(2), and -16.4 ± 2.4%, respectively (all P values P < 0.0001). HOMA IR and HOMA ? significantly decreased while whole body insulin sensitivity index (WBISI) increased (all P values P < 0.001). Conclusion. Eight weeks of VLCD was an effective intervention in obese subjects. These beneficial effects may be associated with enhanced hepatic and whole-body lipolysis and oxidation.
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Analysis and curative effect of ocular ischemic diseases caused by carotid artery stenosis.
Exp Ther Med
PUBLISHED: 02-12-2013
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Carotid artery stenosis is a notable cause of ocular ischemic disease. To analyze the ocular ischemic diseases caused by carotid artery stenosis and to seek effective treatment, a retrospective review of 182 patients with carotid artery stenosis was performed. These patients were administered medical treatment, carotid artery stenting (CAS) or carotid endarterectomy (CEA) and the curative effects of the three different treatments were compared. The results demonstrated that all three treatments helped to improve the disease. Both carotid endarterectomy and carotid artery stenting were more effective than medical treatment (P<0.05). There was no significant difference between carotid endarterectomy and carotid artery stenting (P>0.05). In conclusion, timely diagnosis and suitable treatment for ocular ischemic diseases caused by carotid artery stenosis are necessary due to the complicated clinical manifestation. This study suggested that carotid endarterectomy and carotid artery stenting are effective techniques that may relieve this disease.
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Identification of a novel collagen type ?-binding protein from Streptococcus suis serotype 2.
Vet. J.
PUBLISHED: 01-21-2013
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Streptococcus suis, a major pathogen of pigs, is an emerging zoonotic agent that causes meningitis and septic shock. cbp40 is a putative virulent gene that has been identified using suppression subtractive hybridization performed on the virulent S. suis serotype 2 strain HA9801 and the avirulent S. suis serotype 2 strain T15. Based on predicted protein features showing a shared conserved domain with the collagen-binding protein Cna of Staphylococcus aureus, Cbp40 is likely to function as a direct mediator of collagen adhesion. Here, the cbp40 gene was cloned and the recombinant protein purified. Western blotting using swine convalescent sera confirmed its role as an immunogenic protein. Collagen binding activity could be detected by western affinity blot and ELISA. Conversely, deletion of the cbp40 gene reduced bacterial adhesion to HEp-2 cells, capacity for biofilm formation, and virulence in a zebrafish infection model. The response of the bEnd.3 cell line to infection with the S. suis serotype 2 strain ZY05719 and the cbp40-knockout strain was evaluated using gene expression arrays. The differentially expressed genes were involved in inflammatory and immune responses, leukocyte adhesion and heterophilic cell adhesion. Collectively, these data suggest that Cbp40 plays an important role as an extracellular matrix adhesion protein that interacts with host cells during infection.
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Mast cells and vascular diseases.
Pharmacol. Ther.
PUBLISHED: 01-16-2013
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Mast cells are increasingly being recognized as effector cells in many cardiovascular conditions. Many mast-cell-derived products such as tryptase and chymase can, through their enzymic action, have detrimental effects on blood vessel structure while mast cell-derived mediators such as cytokines and chemokines can perpetuate vascular inflammation. Mice lacking mast cells have been developed and these are providing an insight into how mast cells are involved in cardiovascular diseases and, as knowledge increase, mast cells may become a viable therapeutic target to slow progression of cardiovascular disease.
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DFT study on the reactions of ClO?/BrO? with RCl (R = CH?, C?H?, and C?H?) in gas phase.
J Mol Model
PUBLISHED: 01-08-2013
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Gas-phase reactions of ClO(-)/BrO(-) with RCl (R = CH?, C?H?, and C?H?) have been investigated in detail using the popular DFT functional BHandHLYP/aug-cc-pVDZ level of theory. As a result, our findings strongly suggest that the type of reaction is firstly initiated by a typical SN2 fashion. Subsequently, two competitive substitution steps, named as SN2-induced substitution and SN2-induced elimination, respectively, would proceed before the initial SN2 product ion-dipole complex separates, in which the former exhibits less reactivity than the latter. Those are consistent with relevant experimental results. Moreover, we have also explored reactivity difference for the title reactions in term of some factors derived from methyl group, p-? electronic conjugation, ionization energy (IE), as well as molecular orbital (MO) analysis.
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Effect of steam explosion and microbial fermentation on cellulose and lignin degradation of corn stover.
Bioresour. Technol.
PUBLISHED: 09-11-2011
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In order to increase nutrient values of corn stover, effects of steam explosion (2.5 MPa, 200 s) and Aspergillus oryzae (A. oryzae) fermentation on cellulose and lignin degradation were studied. The results showed the contents of cellulose, hemicellulose and lignin in the exploded corn stover were 8.47%, 50.45% and 36.65% lower than that in the untreated one, respectively (P<0.05). The contents of cellulose and hemicellulose in the exploded and fermented corn stover (EFCS) were decreased by 24.36% and 69.90%, compared with the untreated one (P<0.05); decreased by 17.35% and 38.59%, compared with the exploded one (P<0.05). The scanning electron microscope observations demonstrated that the combined steam explosion and fermentation destructed corn stover. The activities of enzymes in EFCS were increased. The metabolic experiment showed that about 8% EFCS could be used to replace corn meal in broiler diets, which made EFCS become animal feedstuff possible.
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Functional characterization of insulin receptor gene mutations contributing to Rabson-Mendenhall syndrome - phenotypic heterogeneity of insulin receptor gene mutations.
Endocr. J.
PUBLISHED: 08-23-2011
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Rabson-Mendenhall syndrome (RMS) is a rare disorder that presents as severe insulin resistance as a result of mutations present in the insulin receptor (INSR). A Chinese girl with RMS presented with profound diabetes, hyperinsulinemia, acanthosis nigricans, hirsutism, and abnormalities of teeth and nails. Direct sequencing of the patients INSR detected heterozygote mutations at Arg83Gln (R83Q) and Ala1028Val (A1028V), with the former representing a novel mutation. Functional studies of Chinese hamster ovary (CHO) cells transfected with wild-type (WT) and mutant forms of INSR were performed to evaluate the effects of these mutations on receptor expression and activation. Receptor expression, insulin binding activity, and phosphorylation of the R83Q variant were comparable to WT. In contrast, expression of the A1028V receptor was much lower than that of WT INSR, and impairment of insulin binding and autophosphorylation were nearly commensurate with the decrease in expression detected. Reductions in the phosphorylation of IRS-1, Akt, and Erk1/2 (60%, 40%, and 50% of WT, respectively) indicate that the A1028V receptor contributes to impaired signal transduction. In conclusion, INSR mutations associated with RMS were identified. Moreover, the A1028V mutation associated with a decrease in expression of INSR potentially accounts for loss of function of the INSR.
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Modelling the distribution of chickens, ducks, and geese in China.
Agric Ecosyst Environ
PUBLISHED: 07-19-2011
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Global concerns over the emergence of zoonotic pandemics emphasize the need for high-resolution population distribution mapping and spatial modelling. Ongoing efforts to model disease risk in China have been hindered by a lack of available species level distribution maps for poultry. The goal of this study was to develop 1 km resolution population density models for Chinas chickens, ducks, and geese. We used an information theoretic approach to predict poultry densities based on statistical relationships between poultry census data and high-resolution agro-ecological predictor variables. Model predictions were validated by comparing goodness of fit measures (root mean square error and correlation coefficient) for observed and predicted values for ¼ of the sample data which was not used for model training. Final output included mean and coefficient of variation maps for each species. We tested the quality of models produced using three predictor datasets and 4 regional stratification methods. For predictor variables, a combination of traditional predictors for livestock mapping and land use predictors produced the best goodness of fit scores. Comparison of regional stratifications indicated that for chickens and ducks, a stratification based on livestock production systems produced the best results; for geese, an agro-ecological stratification produced best results. However, for all species, each method of regional stratification produced significantly better goodness of fit scores than the global model. Here we provide descriptive methods, analytical comparisons, and model output for Chinas first high resolution, species level poultry distribution maps. Output will be made available to the scientific and public community for use in a wide range of applications from epidemiological studies to livestock policy and management initiatives.
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Serum A-FABP is increased and closely associated with elevated NT-proBNP levels in type 2 diabetic patients treated with rosiglitazone.
PLoS ONE
PUBLISHED: 07-06-2011
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Adipocyte fatty acid-binding protein (A-FABP) has been shown to play important roles in the development of metabolic syndrome, diabetes, and cardiovascular diseases. In this study we investigated the possible role of A-FABP in the development of cardiac dysfunction related to rosiglitazone treatment.
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Cigarette smoking increases risk for incident metabolic syndrome in Chinese men-Shanghai diabetes study.
Biomed. Environ. Sci.
PUBLISHED: 06-07-2011
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To determine whether smoking increases the risk for developing metabolic syndrome (MetS) in Chinese men.
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Electrochemical detection of low concentration chloropropanol using silver nanowire array electrodes in aqueous media.
J Nanosci Nanotechnol
PUBLISHED: 04-01-2011
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In this paper, we report a facile method to fabricate silver nanowire array electrodes (SNAE) with ultra-high detection sensitivity to chloropropanol in the aqueous solution. Silver nanowire arrays were assembled in conventional anodic alumina membranes (AAM) by electrochemical deposition. Subsequently, silver nanowire arrays with an aspect ratio of 5 approximately 6 were deposited on the bottom of AAM. After a complete removal of the AAM , the grown arrays were used as working electrodes in a three-electrode cell. The electrochemical activity of SNAE was tested in the 0.1 mol/L NaClO4 aqueous solution using chloropropanol as analyte by a cyclic voltammetry method. The results show that SNAE display a distinct reduction peak at -1.011 V (vs. SCE) for chloropropanol and the linear dependencies of current on chloropropanol concentration were obtained within the concentration range 1.8 x 10(-7) approximately 2 x 10(-6) mol/L. The detection limit of chloropropanol was 10(-9) mol/L, which is significantly lower than that of their bulk counterparts. In short, SNAE show great potential in the determination of trace chloropropanol.
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Circadian rhythm of circulating fibroblast growth factor 21 is related to diurnal changes in fatty acids in humans.
Clin. Chem.
PUBLISHED: 02-15-2011
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Fibroblast growth factor (FGF) 21 is an endocrine factor actively involved in glucose and lipid metabolism in rodents. However, little is known about its physiological function and regulation in humans. This study investigated the diurnal changes in circulating FGF21 concentrations and their association with other metabolic markers in both obese and lean individuals.
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Improving light extraction of InGaN-based light emitting diodes with a roughened p-GaN surface using CsCl nano-islands.
Opt Express
PUBLISHED: 01-26-2011
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InGaN-based light emitting diodes (LEDs) with a top nano-roughened p-GaN surface are fabricated using self-assembled CsCl nano-islands as etch masks. Following formation of hemispherical GaN nano-island arrays, electroluminescence (EL) spectra of roughened LEDs display an obvious redshift due to partial compression release in quantum wells through Inductively Coupled Plasma (ICP) etching. At a 350-mA current, the enhancement of light output power of LEDs subjected to ICP treatment with durations of 50, 150 and 250 sec compared with conventional LED have been determined to be 9.2, 70.6, and 42.3%, respectively. Additionally, the extraction enhancement factor can be further improved by increasing the size of CsCl nano-island. The economic and rapid method puts forward great potential for high performance lighting devices.
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Stem cell-based therapies in ischemic heart diseases: a focus on aspects of microcirculation and inflammation.
Basic Res. Cardiol.
PUBLISHED: 01-18-2011
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Stem cells possessing the potential to replace damaged myocardium with functional myocytes have drawn increasing attention in the past decade in treating ischemic heart diseases; these diseases are the leading cause of morbidity and mortality in the world. The adult heart has recently been shown to contain a few cardiac stem cells (CSCs) that, in theory, suggest cardiac repair following acute myocardial infarction is possible if the CSC titer could be increased. Stem cell-based therapies, including hematopoietic stem cells and mesenchymal stem cells, were proven to be marginal and transitional. Multiple factors and mechanisms, rather than direct cardiac regeneration are involved in stem cell-mediated cardiac functional improvement. This review will focus on (1) the interaction between inflammation and stem cells; (2) the fate of stem cells at the microcirculatory level, and their subsequent influences on stem cell-based therapies.
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Inhibition of inducible nitric oxide synthase promotes vein graft neoadventitial inflammation and remodelling.
J. Vasc. Res.
PUBLISHED: 02-23-2010
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Grafting veins into the arterial circulation causes endothelial damage and neointimal hyperplasia. However, the remodelling of vein grafts and the contribution of the endothelium is not well understood. Since nitric oxide (NO) has a crucial role in vascular function, we investigated the importance of NO synthases (NOSs) in vein graft re-endothelialization and remodelling in this study.
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Urinary pigment epithelium-derived factor as a marker of diabetic nephropathy.
Am. J. Nephrol.
PUBLISHED: 02-04-2010
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Pigment epithelium-derived factor (PEDF), a serine protease inhibitor, regulates extracellular matrix production in the kidney. We sought the association between urinary PEDF (uPEDF) and development of nephropathy among patients with type 2 diabetes (T2DM).
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Direct relationship between levels of TNF-alpha expression and endothelial dysfunction in reperfusion injury.
Basic Res. Cardiol.
PUBLISHED: 01-21-2010
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We previously found that myocardial ischemia/reperfusion (I/R) initiates expression of tumor necrosis factor-alpha (TNF) leading to coronary endothelial dysfunction. However, it is not clear whether there is a direct relationship between levels of TNF expression and endothelial dysfunction in reperfusion injury. We studied levels of TNF expression by using different transgenic animals expressing varying amounts of TNF in I/R. We crossed TNF overexpression (TNF(++/++)) with TNF knockout (TNF(-/-)) mice; thus we have a heterozygote population of mice with the expression of TNF "in between" the TNF(-/-) and TNF(++/++) mice. Mouse hearts were subjected to 30 min of global ischemia followed by 90 min of reperfusion and their vasoactivity before and after I/R was examined in wild type (WT), TNF(-/-), TNF(++/++) and TNF heterozygote (TNF(-/++), cross between TNF(-/-) and TNF(++/++)) mice. In heterozygote TNF(-/++) mice with intermediate cardiac-specific expression of TNF, acetylcholine-induced or flow-induced endothelial-dependent vasodilation following I/R was between TNF(++/++) and TNF(-/-) following I/R. Neutralizing antibodies to TNF administered immediately before the onset of reperfusion-preserved endothelial-dependent dilation following I/R in WT, TNF(-/++) and TNF(++/++) mice. In WT, TNF(-/++) and TNF(++/++) mice, I/R-induced endothelial dysfunction was progressively lessened by administration of free-radical scavenger TEMPOL immediately before initiating reperfusion. During I/R, production of superoxide (O(2) (.-)) was greatest in TNF(++/++) mice as compared to WT, TNF(-/++) and TNF(-/-) mice. Following I/R, arginase mRNA expression was elevated in the WT, substantially elevated in the TNF(-/++) and TNF(++/++) mice and not affected in the TNF(-/-) mice. These results suggest that the level of TNF expression determines arginase expression in endothelial cells during myocardial I/R, which is one of the mechanisms by which TNF compromises coronary endothelial function in reperfusion injury.
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Ultrasensitive detection using surface enhanced Raman scattering from silver nanowire arrays in anodic alumina membranes.
J Nanosci Nanotechnol
PUBLISHED: 11-26-2009
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Periodical arrays of silver nanowires about 60 nm in diameter were assembled in anodic alumina membranes by electrochemical deposition. After a partial removal of the membrane, the as-grown arrays were used as a surface enhanced Raman scattering substrate. Raman spectra of Rhodamine 6G solutions with different concentrations (10(-6) M, 10(-9) M, 10(-12) M and 10(-13) M) were measured on such substrates. According to a series of measurements, it is found that the Raman signals of the probe solution with a Rhodamine 6G concentration of 10(-13) M can still be detected with a visible light (514.5 nm) excitation. The high detection sensitivity is seldom reported by other silver substrates. Further improvements may be achieved by adjusting the parameters (period, diameter and aspect ratio) of the nanowire arrays. Compared to other substrates, as-fabricated substrates are easy to fabricate, low in cost, flexible to adjust and convenient in measurement. Such substrates may have great potential in the detection of Persistent Organic Pollutants.
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Serum retinol-binding protein 4 is associated with insulin secretion in Chinese people with normal glucose tolerance.
J Diabetes
PUBLISHED: 06-01-2009
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Serum levels of retinol-binding protein 4 (RBP4) are associated with insulin resistance and type 2 diabetes mellitus (T2DM) and may impact on ?-cell function. Thus, the present study investigated the relationship between serum RBP4 and insulin secretion in Chinese people with and without T2DM.
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Fenofibrate reduces serum retinol-binding protein-4 by suppressing its expression in adipose tissue.
Am. J. Physiol. Endocrinol. Metab.
PUBLISHED: 05-22-2009
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Fenofibrate is a peroxisome proliferator-activated receptor-alpha (PPARalpha) activator that has been clinically used to treat dyslipidemia and insulin resistance. To better understand the molecular mechanisms underlying fenofibrate action, we investigated whether fenofibrate affects serum levels of retinol-binding protein-4 (RBP4), an adipocytokine that has recently been shown to link obesity and insulin resistance. Fenofibrate treatment significantly decreased serum RBP4 levels of dyslipidemic patients, which correlated with reduced body weight and increased insulin sensitivity. To elucidate the biochemical mechanisms of fenofibrate action, we investigated the effect of fenofibrate on RBP4 expression in obese rats. Fenofibrate greatly decreased RBP4 mRNA levels in adipose tissue but not in the liver, which correlated with decreased serum RBP4 levels and increased insulin sensitivity in obese rats. Consistent with a direct effect on RBP4 expression, fenofibrate treatment significantly reduced the mRNA expression levels of RPB4 in 3T3-L1 adipocytes. Together, our results demonstrate for the first time that fenofibrate inhibits RPB4 expression in dyslipidemic human subjects and suggest that inhibition of RBP4 expression in adipocytes may provide a mechanism by which fenofibrate improves insulin sensitivity in dyslipidemic patients.
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Aqueous Cr(VI) reduction by electrodeposited zero-valent iron at neutral pH: acceleration by organic matters.
J. Hazard. Mater.
PUBLISHED: 04-03-2009
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This work investigated the effect of co-existing organic matters on aqueous Cr(VI) reduction by electrodeposited zero-valent iron (ED Fe(0)) at neutral pH. The ED Fe(0) prepared in a solution containing mixture of saccharin, L-ascorbic acid and sodium dodecyl sulfate showed higher activity in reducing the aqueous Cr(VI) at neutral pH than that prepared without any organic presence. XRD and SEM indicated that the structure of ED Fe(0) was significantly improved to nano-scale by the presence of organic mixture in the preparation solution. Further, the ED Fe(0) activity in the Cr(VI) reduction at neutral pH was increased by the co-existence of citric acid or oxalic acid in the chromate solution. Electrochemical impedance spectroscopy (EIS) demonstrated that the corrosive current increased with the concentration of organic matter in the reaction solution. With the co-existing organic matters in the preparation solution, the ED Fe(0) corroded more rapidly due to its nano-size, thus the Cr(VI) reduction by the ferrous iron was accelerated. With the co-existing organic matters in the reaction solution, the Cr(VI) reduction was accelerated by a Fe(II) complex as the main electron donor, and a prevention of the passivation due to the Fe(III) and Cr(III) complexes also accelerated the Cr(VI) reduction.
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Serum fibroblast growth factor 21 is associated with adverse lipid profiles and gamma-glutamyltransferase but not insulin sensitivity in Chinese subjects.
J. Clin. Endocrinol. Metab.
PUBLISHED: 03-24-2009
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Fibroblast growth factor (FGF) 21, a hormone primarily secreted by liver, has recently been shown to have beneficial effects on glucose and lipid metabolism and insulin sensitivity in animal models. This study investigated the association of serum FGF21 levels with insulin secretion and sensitivity, as well as circulating parameters of lipid metabolism and hepatic enzymes in Chinese subjects.
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Polymorphism of DsbA-L gene associates with insulin secretion and body fat distribution in Chinese population.
Endocr. J.
PUBLISHED: 02-19-2009
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Disulfide-bond-A oxidoreductase-like protein (DsbA-L) has been suggested to take part in the disulfide bond formation progress of proteins, including insulin and adiponectin. Recent study has demonstrated that expression of DsbA-L was decreased in obese mice and human subject, indicating that DsbA-L might be a potential target for treatment of metabolic diseases. We investigated the association of SNP-1308G/T (rs1917760) of DsbA-L gene with metabolic diseases. 589 normal glucose tolerance (NGT) subjects and 556 type 2 diabetes (T2DM) subjects were recruited. Each group was divided into normal weight (NW) (BMI<24 kg/m(2)) subgroup and overweight/obesity (OW/OB) (BMI>/=24 kg/ m(2)) subgroup. Genotype distributions and allele frequencies of SNP (-1308G/T) in DsbA-L gene were not associated with T2DM and obesity. However, it was observed that T allele carriers had better insulin secretion function compared with non-T allele carriers in NGT-NW group, not only the first phase insulin secretion (P=0.007) but also the second phase insulin secretion (P=0.031). Multiple linear regression analysis revealed that SNP-1308G/T polymorphism (rs1917760) was independently correlated with both first and second phase insulin secretion in NGT-NW group (R(2)=0.055, P=0.007; R(2)=0.029, P=0.041). Otherwise, T carriers had more visceral fat than non-T carriers (P=0.020) in NGT-OW/OB group. In conclusion, the SNP-1308G/T (rs1917760) genotypes of DsbA-L gene might participate in insulin secretion and body fat distribution. It is possible that polymorphisms of DsbA-L gene associated with metabolic diseases.
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Mechanical Deformation Behavior of Nonpolar GaN Thick Films by Berkovich Nanoindentation.
Nanoscale Res Lett
PUBLISHED: 02-02-2009
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In this study, the deformation mechanisms of nonpolar GaN thick films grown on m-sapphire by hydride vapor phase epitaxy (HVPE) are investigated using nanoindentation with a Berkovich indenter, cathodoluminescence (CL), and Raman microscopy. Results show that nonpolar GaN is more susceptible to plastic deformation and has lower hardness than c-plane GaN. After indentation, lateral cracks emerge on the nonpolar GaN surface and preferentially propagate parallel to the ?112?0? orientation due to anisotropic defect-related stresses. Moreover, the quenching of CL luminescence can be observed to extend exclusively out from the center of the indentations along the ?112?0? orientation, a trend which is consistent with the evolution of cracks. The recrystallization process happens in the indented regions for the load of 500 mN. Raman area mapping indicates that the distribution of strain field coincides well with the profile of defect-expanded dark regions, while the enhanced compressive stress mainly concentrates in the facets of the indentation.
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Common variants of hepatocyte nuclear factor 1beta are associated with type 2 diabetes in a Chinese population.
Diabetes
PUBLISHED: 01-23-2009
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Hepatocyte nuclear factor 1beta (HNF1beta) is a transcription factor that is critical for pancreatic cell formation and glucose homeostasis. Previous studies have reported that common variants of HNF1beta were associated with type 2 diabetes in Caucasians and West Africans. However, analysis in the subjects from the Botnia study and Malmö Preventive Project produced conflicting results, and the role for HNF1beta in type 2 diabetes susceptibility remains unclear. We therefore investigated common variants across the HNF1beta gene in a Chinese population.
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Erythropoietin augments the efficacy of therapeutic angiogenesis induced by allogenic bone marrow stromal cells in a rat model of limb ischemia.
Mol. Biol. Rep.
PUBLISHED: 01-12-2009
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Transplantation of adult marrow stromal cells (MSCs) has been developed as a new method of treating severe ischemia diseases by therapeutic angiogenesis. Erythropoietin (EPO) is capable of inducing angiogenesis and inhibiting MSCs apoptosis. The effect of EPO on the therapeutic potency of MSCs transplantation in a rat model of limb ischemia was investigated in the current study. The results indicate that the combined treatment with MSC transplantation and EPO infusion is superior to MSC transplantation alone in the treatment of limb ischemia. MSCs transplantation and EPO infusion could enhance the angiogenic effect of each other to achieve a better therapeutic effect. This combination therapy may become a more effective approach for ischemia diseases of the limbs.
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Role of TNF-alpha in vascular dysfunction.
Clin. Sci.
PUBLISHED: 01-03-2009
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Healthy vascular function is primarily regulated by several factors including EDRF (endothelium-dependent relaxing factor), EDCF (endothelium-dependent contracting factor) and EDHF (endothelium-dependent hyperpolarizing factor). Vascular dysfunction or injury induced by aging, smoking, inflammation, trauma, hyperlipidaemia and hyperglycaemia are among a myriad of risk factors that may contribute to the pathogenesis of many cardiovascular diseases, such as hypertension, diabetes and atherosclerosis. However, the exact mechanisms underlying the impaired vascular activity remain unresolved and there is no current scientific consensus. Accumulating evidence suggests that the inflammatory cytokine TNF (tumour necrosis factor)-alpha plays a pivotal role in the disruption of macrovascular and microvascular circulation both in vivo and in vitro. AGEs (advanced glycation end-products)/RAGE (receptor for AGEs), LOX-1 [lectin-like oxidized low-density lipoprotein receptor-1) and NF-kappaB (nuclear factor kappaB) signalling play key roles in TNF-alpha expression through an increase in circulating and/or local vascular TNF-alpha production. The increase in TNF-alpha expression induces the production of ROS (reactive oxygen species), resulting in endothelial dysfunction in many pathophysiological conditions. Lipid metabolism, dietary supplements and physical activity affect TNF-alpha expression. The interaction between TNF-alpha and stem cells is also important in terms of vascular repair or regeneration. Careful scrutiny of these factors may help elucidate the mechanisms that induce vascular dysfunction. The focus of the present review is to summarize recent evidence showing the role of TNF-alpha in vascular dysfunction in cardiovascular disease. We believe these findings may prompt new directions for targeting inflammation in future therapies.
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Oral supplementation with cholecalciferol 800 IU ameliorates albuminuria in Chinese type 2 diabetic patients with nephropathy.
PLoS ONE
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Low vitamin D levels can be associated with albuminuria, and vitamin D analogs are effective anti-proteinuric agents. The aim of this study was to investigate differences in vitamin D levels between those with micro- and those with macroalbuminuria, and to determine whether low dose cholecalciferol increases vitamin D levels and ameliorates albuminuria.
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A microalbuminuria threshold to predict the risk for the development of diabetic retinopathy in type 2 diabetes mellitus patients.
PLoS ONE
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To test the hypothesis that a microalbuminuria (MA) threshold can help predict the risk for the development of diabetic retinopathy (DR) in type 2 diabetes mellitus (T2DM)_ patients.
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Multiple inflammatory myofibroblastic tumor of the duodenum: case report and literature review.
J. Gastrointest. Surg.
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Inflammatory myofibroblastic tumor (IMT) is a rare low-grade malignant mesenchymal tumor, which can occur at any location, although the lung is the most commonly affected organ. It is extremely rare in the duodenum and only two cases have been reported previously. We report, to our knowledge, the first case of multiple neoplastic lesions.
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Interaction between M-like protein and macrophage thioredoxin facilitates antiphagocytosis for Streptococcus equi ssp. zooepidemicus.
PLoS ONE
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Streptococcus equi ssp. zooepidemicus (S. zooepidemicus, S.z) is one of the common pathogens that can cause septicemia, meningitis, and mammitis in domesticated species. M-like protein (SzP) is an important virulence factor of S. zooepidemicus and contributes to bacterial infection and antiphagocytosis. The interaction between SzP of S. zooepidemicus and porcine thioredoxin (TRX) was identified by the yeast two-hybrid and further confirmed by co-immunoprecipitation. SzP interacted with both reduced and the oxidized forms of TRX without inhibiting TRX activity. Membrane anchored SzP was able to recruit TRX to the surface, which would facilitate the antiphagocytosis of the bacteria. Further experiments revealed that TRX regulated the alternative complement pathway by inhibiting C3 convertase activity and associating with factor H (FH). TRX alone inhibited C3 cleavage and C3a production, and the inhibitory effect was additive when FH was also present. TRX inhibited C3 deposition on the bacterial surface when it was recruited by SzP. These new findings indicated that S. zooepidemicus used SzP to recruit TRX and regulated the alternative complement pathways to evade the host immune phagocytosis.
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JoVE Visualize is a tool created to match the last 5 years of PubMed publications to methods in JoVE's video library.

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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.