A novel method to quantify local CpG methylation density by regional methylation elongation assay on microarray

<p>Abstract</p> <p>Background</p> <p>DNA methylation based techniques are important tools in both clinical diagnostics and therapeutics. But most of these methods only analyze a few CpG sites in a target region. Indeed, difference of site-specific methylation may also lead to a change of methylation density in many cases, and it has been found that the density of methylation is more important than methylation of single CpG site for gene silencing.</p> <p>Results</p> <p>We have developed a novel approach for quantitative analysis of CpG methylation density on the basis of microarray-based hybridization and incorporation of Cy5-dCTP into the Cy3 labeled target DNA by using Taq DNA Polymerase on microarray. The quantification is achieved by measuring Cy5/Cy3 signal ratio which is proportional to methylation density. This methylation-sensitive technique, termed RMEAM (regional methylation elongation assay on microarray), provides several advantages over existing methods used for methylation analysis. It can determine an exact methylation density of the given region, and has potential of high throughput. We demonstrate a use of this method in determining the methylation density of the promoter region of the tumor-related gene <it>MLH1, TERT </it>and <it>MGMT </it>in colorectal carcinoma patients.</p> <p>Conclusion</p> <p>This technique allows for quantitative analysis of regional methylation density, which is the representative of all allelic methylation patterns in the sample. The results show that this technique has the characteristics of simplicity, rapidness, specificity and high-throughput.</p

The value of diffusion-weighted imaging in assessing the ADC changes of tissues adjacent to breast carcinoma

<p>Abstract</p> <p>Background</p> <p>To define a threshold value of apparent diffusion coefficient (ADC) with which malignant breast lesions can be distinguished from benign lesions, and to evaluate the ADC change of peri-tumor tissue in breast carcinoma by echo planar-diffusion weighted imaging (EPI-DWI).</p> <p>Methods</p> <p>57 breast lesions were scanned by routine MRI and EPI-DWI. The ADC values were compared between malignant and benign lesions. The sensitivity and specificity of EPI-DWI and the threshold ADC value were evaluated by Receiver Operating Characteristic curve (ROC). The ADC values of malignant lesion and layered peri-tumor tissues (from innermost layer 1 to outermost layer 4 with 5 mm every layer) in different directions were compared and the ADC values among different layers were compared.</p> <p>Results</p> <p>The ADC value of 35 malignant lesions was statistically lower than that of 22 benign lesions (P < 0.05). In ROC curve, the threshold value was 1.24 +/- 0.25*10E-3 mm²/s (b = 500) or 1.20 +/- 0.25*10E-3 mm²/s (b = 1000). The ADC value of malignant lesions was statistically lower than that of peri-tumor tissues in different directions (P < 0.05). For peri-tumor tissues, the ADC values increased gradually from layer 1 to layer 4 and there was a significant difference between the ADC values of layer 1 and layer 2 (P < 0.05); while from layer 2 outwards, there was no statistical difference among different layers.</p> <p>Conclusion</p> <p>ADC value was a sensitive and specific parameter that could help to differentiate benign and malignant breast lesions. ADC changes in tissues adjacent to breast carcinoma could be detected by EPI-DWI, which made EPI-DWI a promising method for helping to determine surgical scope of breast carcinoma.</p

Pompes de Knudsen et Leur Application Potentielle à l'Actionnement de Micro-Muscles Pneumatiques Artificiels

Knudsen micropumps are micropumps without any moving part, which are also known as thermal transpiration micropumps or Knudsen compressors. They are able to pump gases with a flow generated by only a temperature gradient applied along the solid walls of the pump, i.e. without need of any pressure gradient. On the other hand, they can create a pressure difference and generate vacuum. These micropumps can be used for a variety of applications, such as vacuum generation, gas separation, gas chromatography, gas sampling, heat dissipation, etc. For this reason, they have attracted the interest of various researchers in the past few decades. Different designs of Knudsen pumps have thus been proposed, in an attempt to optimize performances in terms of pressure difference and mass flowrate.The present work aims to design and path the way to manufacture a specific Knudsen micropump for the actuation of artificial pneumatic micro-muscles controlled by a level of vacuum.Artificial muscles, also known as muscle-like actuators, can be driven by external stimuli leading to different deformations. One kind of artificial muscle is the so-called pneumatic artificial muscle (PAM); it is actuated by a pressure difference imposed between the inner volume of the muscle and the external environment. In recent years, a new kind of PAM has been developed. It is controlled by a level of vacuum, instead of being inflated like conventional pneumatic muscles. As Knudsen pumps are suitable for generating vacuum and have very small dimensions, they could be powerful tools for the control of micro-PAM. Coupling Knudsen pumps with pneumatic artificial micro-muscles appears as an original and innovative field of investigation with interesting scientific and technical challenges. The potential applications could concern micro swimmers, micro robots and micro grippers, or more complex microsystems designed for energy conversion and storage.In the present work, an original design of multistage Knudsen pump is proposed and analyzed numerically with a tool able to optimize the design according to the desired performances of the controlled pneumatic muscle. Each stage of the Knudsen pump is made of several parallel microchannels connected to small reservoirs. Different kinds of microchannels are designed, successfully manufactured and experimentally characterized with rarefied gas flows, to demonstrate the suitability of the fabrication process to manufacture the complete Knudsen pump, which should be leak free and reliable. Some 3D printed mini- and micro-muscles are also designed, and their behavior is numerically and experimentally investigated. The combination of Knudsen pumps and artificial micro-muscles is then analyzed. An initial concept and preliminary calculations of the dynamic performances of such a combination are proposed, leading to perspectives for a future complete microdevice.Les micropompes de Knudsen sont des micropompes sans aucune pièce mobile, également connues sous le nom de micropompes à transpiration thermique ou de compresseurs Knudsen. Elles sont capables de créer des écoulements de gaz avec un débit généré uniquement par un gradient de température appliqué le long des parois solides de la pompe, c'est-à-dire sans nécessiter de gradient de pression. En revanche, elles peuvent créer une différence de pression et générer du vide. Ces micropompes peuvent être utilisées pour diverses applications, telles que la production de vide, la séparation des gaz, la chromatographie en phase gazeuse, l'échantillonnage des gaz, la dissipation de la chaleur, etc. C'est pourquoi elles ont suscité l'intérêt de plusieurs chercheurs au cours des dernières décennies. Différentes conceptions de pompes de Knudsen ont ainsi été proposées, dans le but d'optimiser les performances en termes de différence de pression et de débit massique.Le présent travail vise à concevoir une micropompe de Knudsen spécifique pour l'actionnement de micro-muscles pneumatiques artificiels contrôlés par un niveau de vide, et à étudier la manière de la fabriquer.Les muscles artificiels, également connus sous le nom d'actionneurs de type musculaire, peuvent être actionnés par des stimuli externes conduisant à différentes déformations. Un type de muscle artificiel est le muscle artificiel pneumatique (PAM) ; il est actionné par une différence de pression imposée entre le volume interne du muscle et l'environnement externe. Ces dernières années, un nouveau type de PAM a été développé. Il est contrôlé par un niveau de vide, au lieu d'être gonflé comme les muscles pneumatiques conventionnels. Comme les pompes de Knudsen sont adaptées à la production de vide et ont des dimensions très réduites, elles pourraient être des outils particulièrement adaptés à la commande des micro-PAM. Le couplage des pompes de Knudsen avec des micro-muscles artificiels pneumatiques apparaît comme un champ d'investigation original et innovant, avec des défis scientifiques et techniques passionnants. Les applications potentielles pourraient concerner des micronageurs, des microrobots et des micro-préhenseurs, ou des microsystèmes plus complexes destinés à la conversion et le stockage d'énergie.Dans le présent travail, un design original de pompe de Knudsen à plusieurs étages est proposé et analysé numériquement à l'aide d'un outil capable d'optimiser le concept en fonction des performances souhaitées pour le muscle pneumatique contrôlé. Chaque étage de la pompe de Knudsen est constitué de plusieurs microcanaux parallèles reliés à de petits réservoirs. Différents types de microcanaux sont conçus, fabriqués avec succès et caractérisés expérimentalement avec des écoulements de gaz raréfiés, afin de démontrer la capacité du processus de fabrication à fabriquer une pompe de Knudsen complète, étanche et fiable. Des mini et micro-muscles réalisés par impression 3D sont également conçus et leur comportement est étudié numériquement et expérimentalement. La combinaison des pompes de Knudsen et des micro-muscles artificiels est ensuite analysée. Un concept initial et des calculs préliminaires des performances dynamiques d'une telle combinaison sont proposés, conduisant à des perspectives pour un futur microdispositif complet

Pompes de Knudsen et Leur Application Potentielle à l'Actionnement de Micro-Muscles Pneumatiques Artificiels

Knudsen micropumps are micropumps without any moving part, which are also known as thermal transpiration micropumps or Knudsen compressors. They are able to pump gases with a flow generated by only a temperature gradient applied along the solid walls of the pump, i.e. without need of any pressure gradient. On the other hand, they can create a pressure difference and generate vacuum. These micropumps can be used for a variety of applications, such as vacuum generation, gas separation, gas chromatography, gas sampling, heat dissipation, etc. For this reason, they have attracted the interest of various researchers in the past few decades. Different designs of Knudsen pumps have thus been proposed, in an attempt to optimize performances in terms of pressure difference and mass flowrate.The present work aims to design and path the way to manufacture a specific Knudsen micropump for the actuation of artificial pneumatic micro-muscles controlled by a level of vacuum.Artificial muscles, also known as muscle-like actuators, can be driven by external stimuli leading to different deformations. One kind of artificial muscle is the so-called pneumatic artificial muscle (PAM); it is actuated by a pressure difference imposed between the inner volume of the muscle and the external environment. In recent years, a new kind of PAM has been developed. It is controlled by a level of vacuum, instead of being inflated like conventional pneumatic muscles. As Knudsen pumps are suitable for generating vacuum and have very small dimensions, they could be powerful tools for the control of micro-PAM. Coupling Knudsen pumps with pneumatic artificial micro-muscles appears as an original and innovative field of investigation with interesting scientific and technical challenges. The potential applications could concern micro swimmers, micro robots and micro grippers, or more complex microsystems designed for energy conversion and storage.In the present work, an original design of multistage Knudsen pump is proposed and analyzed numerically with a tool able to optimize the design according to the desired performances of the controlled pneumatic muscle. Each stage of the Knudsen pump is made of several parallel microchannels connected to small reservoirs. Different kinds of microchannels are designed, successfully manufactured and experimentally characterized with rarefied gas flows, to demonstrate the suitability of the fabrication process to manufacture the complete Knudsen pump, which should be leak free and reliable. Some 3D printed mini- and micro-muscles are also designed, and their behavior is numerically and experimentally investigated. The combination of Knudsen pumps and artificial micro-muscles is then analyzed. An initial concept and preliminary calculations of the dynamic performances of such a combination are proposed, leading to perspectives for a future complete microdevice.Les micropompes de Knudsen sont des micropompes sans aucune pièce mobile, également connues sous le nom de micropompes à transpiration thermique ou de compresseurs Knudsen. Elles sont capables de créer des écoulements de gaz avec un débit généré uniquement par un gradient de température appliqué le long des parois solides de la pompe, c'est-à-dire sans nécessiter de gradient de pression. En revanche, elles peuvent créer une différence de pression et générer du vide. Ces micropompes peuvent être utilisées pour diverses applications, telles que la production de vide, la séparation des gaz, la chromatographie en phase gazeuse, l'échantillonnage des gaz, la dissipation de la chaleur, etc. C'est pourquoi elles ont suscité l'intérêt de plusieurs chercheurs au cours des dernières décennies. Différentes conceptions de pompes de Knudsen ont ainsi été proposées, dans le but d'optimiser les performances en termes de différence de pression et de débit massique.Le présent travail vise à concevoir une micropompe de Knudsen spécifique pour l'actionnement de micro-muscles pneumatiques artificiels contrôlés par un niveau de vide, et à étudier la manière de la fabriquer.Les muscles artificiels, également connus sous le nom d'actionneurs de type musculaire, peuvent être actionnés par des stimuli externes conduisant à différentes déformations. Un type de muscle artificiel est le muscle artificiel pneumatique (PAM) ; il est actionné par une différence de pression imposée entre le volume interne du muscle et l'environnement externe. Ces dernières années, un nouveau type de PAM a été développé. Il est contrôlé par un niveau de vide, au lieu d'être gonflé comme les muscles pneumatiques conventionnels. Comme les pompes de Knudsen sont adaptées à la production de vide et ont des dimensions très réduites, elles pourraient être des outils particulièrement adaptés à la commande des micro-PAM. Le couplage des pompes de Knudsen avec des micro-muscles artificiels pneumatiques apparaît comme un champ d'investigation original et innovant, avec des défis scientifiques et techniques passionnants. Les applications potentielles pourraient concerner des micronageurs, des microrobots et des micro-préhenseurs, ou des microsystèmes plus complexes destinés à la conversion et le stockage d'énergie.Dans le présent travail, un design original de pompe de Knudsen à plusieurs étages est proposé et analysé numériquement à l'aide d'un outil capable d'optimiser le concept en fonction des performances souhaitées pour le muscle pneumatique contrôlé. Chaque étage de la pompe de Knudsen est constitué de plusieurs microcanaux parallèles reliés à de petits réservoirs. Différents types de microcanaux sont conçus, fabriqués avec succès et caractérisés expérimentalement avec des écoulements de gaz raréfiés, afin de démontrer la capacité du processus de fabrication à fabriquer une pompe de Knudsen complète, étanche et fiable. Des mini et micro-muscles réalisés par impression 3D sont également conçus et leur comportement est étudié numériquement et expérimentalement. La combinaison des pompes de Knudsen et des micro-muscles artificiels est ensuite analysée. Un concept initial et des calculs préliminaires des performances dynamiques d'une telle combinaison sont proposés, conduisant à des perspectives pour un futur microdispositif complet

Effect of Dietary Supplementation of Glycyrrhetinic Acid and Tea Polyphenols on Depuration of 2-methylisoborneol from Blunt Snout Bream, Megalobrama amblycephala

Abstract_Off-flavor is a serious issue in cultured fish. It affects marketability and texture of fish and causes great economic losses in the aquaculture industry. Holding fish in a clean-water environment for some time is an effective method to depurate them although it involves weight loss. This study investigates the potential effects of dietary supplementation of glycyrrhetinic acid (GA) and tea polyphenols (TP) on the depuration of the strong odors of 2- methylisoborneol (MIB) from blunt snout bream, Megalobrama amblycephala. 560 fish, initial average weight of 48.75±0.48 g were distributed into 28 tanks at a rate of 20 fish per tank. Three diets, namely the control diet, a GA supplemented diet (0.3 g/kg), and a (TP) supplemented diet (0.3 g/kg) were used in this study. The control diet was randomly assigned to 20 tanks, 4 tanks with clean water (control), or with water containing 1μg/L MIB. During the first 28-day the fish in each treatment were hand-fed to apparent satiation three times daily. In the second phase (29-42 day), the control, GA, and TP treatments were divided into four groups: MIB, low density (LD), high density (HD), and dynamic sampling (DS) with twenty fish in DS, and fifteen fish in the others. Fish in LD, HD, and DS in all treatments were starved in clean water. Fish in the DS treatment were sampled at 0, 24, 48, 72 hours, at 7 and 14 days. No differences were observed in body weights between groups within the 28-day feeding trial (P>0.05). Fish in GA, LD, and HD groups had significantly lower hepatosomatic index (HSI) and intraperitoneal fat ratios (IPF) than the control, MIB, and TP groups (P<0.05). After 28 and 42 days, fish in the MIB group had higher MIB concentrations than the other groups (P<0.05). Scores of sensory characteristics were similar, with no statistical differences between the control, GA, and TP groups (P>0.05). MIB content decreased significantly in relation to longer depuration times (P<0.05). Fish weight in LD and HD treatments declined by 10% and 12% respectively after 14-day fasting. In conclusion, clean water depuration for fourteen days is an effective method to purge off-flavored flesh although it involves weight loss and dietary supplementation of GA and TP which also depurate MIB from flesh of Megalobrama amblycephala

3D micro-structures for rarefied gas flow applications manufactured via two-photon-polymerization

International audienceIn this work, the two-photon-polymerization (TPP) fabrication technique was employed for the first time to manufacture with success three-dimensional (3D) micro-structures suitable for confined rarefied gas flows. Four different micro-tubes of simple geometry have been tested in vacuum conditions. The geometry of the micro-tubes was characterized via a focus-variation 3D optical measurement microscope, a digital microscope and a X-ray µ-tomography. Mass flow rate measurements of pressure-driven rarefied gas flows of nitrogen in slip and transition regimes are were compared to theoretical values obtained via the kinetic theory of gases. The experimental measurements were realized via the constant volume technique. The good agreement obtained between experimental and numerical results proves the feasibility of using this fabrication technique to create well controlled 3D shaped microsystems for rarefied gas flows applications

Extremely efficient flexible organic solar cells with a graphene transparent anode: Dependence on number of layers and doping of graphene

Graphene has shown tremendous potential as a transparent conductive electrode (TCE) for flexible organic solar cells (OSCs). However, the trade-off between electrical conductance and transparency as well as surface roughness of the graphene TCE with increasing layer number limits power conversion efficiency (PCE) enhancement and its use for large-area OSCs. Here, we use a 300 nm-thick poly[(2,5-bis(2-hexyldecyloxy)phenylene)-alt-(5,6-difluoro-4,7-di(thiophen-2-yl)benzo[c]-[1,2,5]thiadiazole)]:[6,6]-phenyl-C-butyric acid methyl ester blend as the photoactive layer and a benzimidazole (BI)-doped graphene as the transparent anode to demonstrate efficient OSCs with good flexibility. It is found that 3 layer (L) graphene had the best balance between sheet resistance, optical transmittance and surface roughness for optimized cell design. A 0.2 cm cell with a 3L BI-doped graphene anode had a PCE of 6.85%, which is one of the highest PCE values reported so far for flexible graphene anode-based OSCs. The flexible cells were mechanically robust, showing only a small performance degradation during up to 250 flexing cycles. Moreover, the combination of the thick photoactive layer with the optimized 3L BI-doped graphene TCE enabled production of 1.6 cm flexible OSCs with a PCE of 1.8%. Our work illustrates the importance of graphene TCE development for flexible OSCs as well as other wearable optoelectronic devices

Quantitative reverse transcriptase-polymerase chain reaction validation of mature miRNA expression levels in the normal-fat diet (NFD) and high-fat diet (HFD) groups.

<p>Box and whisker plots of the expression levels of the indicated miRNAs in the NFD and HFD groups (n = 10 replicates per group). The expression level of each miRNA was normalized to that of Rpl13a. The upper and lower limits of the box are the first and third quartiles, and the horizontal line inside the box is the second quartile (median). *<i>P</i><0.05 and **<i>P</i><0.01 by unpaired Student's <i>t</i>-tests. NS, no significant difference.</p

Predicted lipid metabolism-related miRNA target genes that were regulated by exposure to a high-fat diet.

<p>Schematic representation of potential determinants of the pathogenesis of hepatic steatosis in blunt snout bream.</p