Heat Transfer Around a Circular Cylinder in the Laminar Zone

The present research work is based on the domain of Computational Fluid Dynamics (CFD). The entire work is done in the FLUENT component of ANSYS. The study of flow property has been divided into three phases. The first phase was getting familiar with the software ANSYS-FLUENT and learning its application and utility on the problem of a lid-driven square cavity. The work was done for Newtonian (n=1) fluid flow for a set of Reynolds numbers (100<Re<10,000). The flow was incompressible and in Laminar Regime.The next phase of the work was to study the problem in hand, i.e., flow past a circular cylinder for a square domain in a unsteady state condition to determine the value of drag coefficient. The flow was taken to be incompressible and in the laminar regime. Here the fluid considered was Newtonian fluid (n=1) .The values of the drag-coefficient obtained were validated from the literature. Then the final task was to observe the heat transfer flow around circular cylinder for a unsteady state condition and a bit more complicated geometry, i.e., an interim between square and circular geometry for a Newtonian fluid. The study was done by varying the Reynolds number (60<Re<150). The values of drag-coefficient, lift-coeffcient versus time were plotted, and Average Nusselt number versus the Prandtl number were plotted in the considered Reynolds number range. The flow pattern in an unsteady laminar incompressible flow was also studied

Effect of kisspeptin on in vitro maturation of sheep oocytes

Aim: The aim of this study was to investigate the effect of kisspeptin (KP) on in vitro maturation (IVM) of sheep oocytes aspirated from the ovaries collected from slaughterhouse. Materials and Methods: Two different experiments were conducted to investigate the effect of KP (5, 10 and 15 μg/ml) alone (experiment 1) or in combination with follicle-stimulating hormone (FSH), luteinizing hormone (LH), and Estradiol (E2) (experiment 2) on IVM of sheep oocytes. Tissue culture medium 199 supplemented with Gentamicin was used as control medium. Good quality oocytes were randomly allocated into different IVM media and cultured at 38.5°C in 5% CO2 under humidified atmosphere for 24 h. The oocytes were evaluated for their cumulus cell expansion (CCE) and extrusion of the 1st polar body (PB) at the end of maturation. Results: The proportion of oocytes showing CCE and extrusion of PB was highest when the oocytes were matured in the medium supplemented with 10 μg/ml of KP. In experiment 2, oocytes were matured in 12 different maturation media (G1-G12: G1: Control, G2: KP alone, G3: FSH, G4: FSH+KP, G5: LH, G6: LH+KP, G7: E2, G8: E2+KP, G9: FSH+LH+E2, G10: FSH+LH+E2+KP, G11: FSH+LH+E2+fetal bovine serum (FBS), G12: FSH+LH+E2+FBS+KP). The proportion of oocytes showing cumulus expansion and PB extrusion was highest (98.33±1.05 and 89.17±2.38) when they were matured in FSH+LH+E2+FBS+KP (G12) and was significantly higher than other groups. The proportion of CCE and extrusion of PB was significantly increased when KP was supplemented to FSH and E2, but no effect was observed with LH. The maturation rates were significantly increased when FSH, LH, and E2 (G9) containing media were additionally supplemented with KP (G10). Conclusion: This study demonstrated that the addition of KP (10 μg/ml) to the FSH, LH, and E2 supplemented media would enhance the sheep oocyte maturation in vitro

A luminal glycoprotein drives dose-dependent diameter expansion of the Drosophila melanogaster hindgut tube.

International audienceAn important step in epithelial organ development is size maturation of the organ lumen to attain correct dimensions. Here we show that the regulated expression of Tenectin (Tnc) is critical to shape the Drosophila melanogaster hindgut tube. Tnc is a secreted protein that fills the embryonic hindgut lumen during tube diameter expansion. Inside the lumen, Tnc contributes to detectable O-Glycans and forms a dense striated matrix. Loss of tnc causes a narrow hindgut tube, while Tnc over-expression drives tube dilation in a dose-dependent manner. Cellular analyses show that luminal accumulation of Tnc causes an increase in inner and outer tube diameter, and cell flattening within the tube wall, similar to the effects of a hydrostatic pressure in other systems. When Tnc expression is induced only in cells at one side of the tube wall, Tnc fills the lumen and equally affects all cells at the lumen perimeter, arguing that Tnc acts non-cell-autonomously. Moreover, when Tnc expression is directed to a segment of a tube, its luminal accumulation is restricted to this segment and affects the surrounding cells to promote a corresponding local diameter expansion. These findings suggest that deposition of Tnc into the lumen might contribute to expansion of the lumen volume, and thereby to stretching of the tube wall. Consistent with such an idea, ectopic expression of Tnc in different developing epithelial tubes is sufficient to cause dilation, while epidermal Tnc expression has no effect on morphology. Together, the results show that epithelial tube diameter can be modelled by regulating the levels and pattern of expression of a single luminal glycoprotein

Crystallization-Induced Dynamic Resolution toward the Synthesis of (<i>S</i>)‑7-Amino‑5<i>H</i>,7<i>H</i>‑dibenzo[<i>b</i>,<i>d</i>]‑azepin-6-one: An Important Scaffold for γ‑Secretase Inhibitors

An enantioselective synthesis of (<i>S</i>)-7-amino-5<i>H</i>,7<i>H</i>-dibenzo­[<i>b</i>,<i>d</i>]­azepin-6-one (<i>S</i>-<b>1</b>) is described. The key step in the sequence involved crystallization-induced dynamic resolution (CIDR) of compound <b>7</b> using Boc-d-phenylalanine as a chiral resolving agent and 3,5-dichlorosalicylaldehyde as a racemization catalyst to afford <i>S</i>-<b>1</b> in 81% overall yield with 98.5% enantiomeric excess

The Triple-Repeat Protein Anakonda Controls Epithelial Tricellular Junction Formation in Drosophila

In epithelia, specialized tricellular junctions (TCJs) mediate cell contacts at three-cell vertices. TCJs are fundamental to epithelial biology and disease, but only a few TCJ components are known, and how they assemble at tricellular vertices is not understood. Here we describe a transmembrane protein, Anakonda (Aka), which localizes to TCJs and is essential for the formation of tricellular, but not bicellular, junctions in Drosophila. Loss of Aka causes epithelial barrier defects associated with irregular TCJ structure and geometry, suggesting that Aka organizes cell corners. Aka is necessary and sufficient for accumulation of Gliotactin at TCJs, suggesting that Aka initiates TCJ assembly by recruiting other proteins to tricellular vertices. Aka’s extracellular domain has an unusual tripartite repeat structure that may mediate self-assembly, directed by the geometry of tricellular vertices. Conversely, Aka’s cytoplasmic tail is dispensable for TCJ localization. Thus, extracellular interactions, rather than TCJ-directed intracellular transport, appear to mediate TCJ assembly

Tnc is a glycosylated intralumial matrix-component.

<p>(A) Tnc from wild type and <i>tnc^13c</i> mutant embryos and larvae (l) were detected on western blot and resided as high-molecular weight species in the stacking gel (stippled line indicates end of stacking gel). Anti-α-Tubulin was used as loading control. (B) Protein extracts from stage 16 wild type embryos were subjected to deglycosylation (no enz = no enzyme, N-Gly = N-Glycanase (PNGase F), O-Gly = O-Glycanase, O-Gly+ = O-Glycanase+Sialidase+β(1-4) Galactosidase+β-N-Acetylglucosaminidase). Addition of O-glycanase caused slightly faster migration of Tnc. (C–H) Embryos were co-labelled for the Tn antigen (green) and Crb (magenta) (C, D, F and G) or with VVA (E and H). Anti-Tn stains the wild type lumen with highest intensity in Si at stages 15 and 16 (C and D). The staining is reduced in mutant embryos (F and G). Arrows point to the Si/Li border. VVA also labels the wild type lumen (E) stronger than the mutant lumen (H). The embryos were processed in parallel and the hindgut was imaged at similar views with identical confocal settings. (I) Wild type embryos were prepared with Clark's fixation and stained for Tnc (I, green) and the Tn antigen (I′, magenta). The merged image (I″) shows partial overlap of the staining. Arrow points to the Si/Li border. (J) High magnification of the hindgut in (I), showing a striated pattern of Tnc-staining. Scale bars: 10 µm in I, 5 µm in J.</p

Tnc acts non-cell-autonomously.

<p>(A) <i>enGAL4</i> drives expression of <i>UAS-GFP</i> in the dorsal Li (bracket), as seen by labelling with anti-GFP (green) and anti-Crb (magenta). (B and C) Stage 16 embryos stained for DECad and Crb show that <i>enGAL4</i>-driven expression of <i>tnc</i> in dorsal Li (bracket) caused enlarged apical cell circumferences in both dorsal and ventral Li (C), when compared to embryos that only express <i>enGAL4</i> (B). (D–G) <i>enGAL4</i> drives expression of <i>UAS-GFP</i> (green) in a cluster of cells in the anterior salivary gland (D, stage 13). <i>enGAL4</i>-driven expression of Tnc in salivary glands resulted in local tube dilation (E). By merging serial z-stacked images, the apical cell circumferences were visualized (F). Note that <i>enGAL4</i> drives expression in one side of the tube, but all cells at the perimeter show enlarged apical cell circumference. Co-staining for Tnc (green) and Crb (magenta) shows that luminal Tnc localizes to the dilated part of the salivary gland lumen (G). (H) A possible model for the function of Tnc during lumen dilation. Expression of <i>tnc</i> in the tubular epithelium causes tube dilation according to the level of expression (“low" and “high") and causes differential dilation along the tube. Once inside the lumen, Tnc acts on surrounding cells, possibly by generating a mechanical pressure, to expand the tube wall.</p

Tnc promotes hindgut diameter-expansion in a dose-dependent manner.

<p>(A) The distribution of <i>tnc</i> transcripts (left) and Tnc protein (right) is shown in the hindgut for stages 12 to 16. At stage 12 (lateral view) <i>tnc</i> expression is prominent in the ventral hindgut, and anti-Tnc densely stains the ventral lumen at stages 12 and 13. From stage 13 to 15 (dorsal views), <i>tnc</i> expression is higher in Si than in Li, and Tnc is seen in intracellular puncta in Si. At stage 16 (dorsal views), <i>tnc</i> mRNA levels decline and Tnc is detected only inside the lumen. (B–F) Embryos were labelled for Crb and DECad (both in white) to visualize hindgut lumen size in the wild type (B) and in embryos that express <i>UAS</i>-<i>tnc</i> in the hindgut driven by <i>69B-GAL4</i> (C), <i>bynGAL4</i> (D), <i>drmGAL4</i> (E) and <i>enGAL4</i> (F). All images are projections of serial z-stacks at dorsal view. Drawings of the respective lumens (right) also indicate the pattern of GAL4 expression (dark shading represents strong GAL4 expression). The size of lumen diameter correlated with GAL4 expression level. (G–J) Wild type and <i>UAS-tnc/BynGAL4</i> (byn>tnc) embryos were co-labelled with anti-Crb (magenta) and anti-Dg (green) (G and H) and with anti-Crb and anti-DECad (both in white, I and J). Compared to the wild type, byn>tnc embryos have enlarged outer and inner tube diameter (stippled and full lines in G and H) and a flattened tubular epithelium (compare difference in inner and outer diameter in G and H). byn>tnc embryos also show enlarged apical cell circumferences and fewer cells along the Li tube axis (I and J, equal-sized brackets span 13, respective 10, cells along the dorsal-ventral boundary). (K) The mean diameter of Li (green) and area of Si (magenta) are shown for wild type embryos and embryos with GAL4-driven <i>tnc</i> expression. Note that <i>drmGAL4</i>, which drives strong expression in Si, causes a relatively larger dilation of Si than Li when compared to the other genotypes. P-value<0.05. Error bars represent standard error of mean (n = 8). Scale bars: 20 µm in A, 20 µm in B (B–F), 10 µm in I (I and J). See also <a href="http://www.plosgenetics.org/article/info:doi/10.1371/journal.pgen.1002850#pgen.1002850.s005" target="_blank">Figures S5</a> and <a href="http://www.plosgenetics.org/article/info:doi/10.1371/journal.pgen.1002850#pgen.1002850.s006" target="_blank">S6</a>.</p