A structure-preserving parametric finite element method for area-conserved generalized mean curvature flow

We propose and analyze a structure-preserving parametric finite element method (SP-PFEM) to simulate the motion of closed curves governed by area-conserved generalized mean curvature flow in two dimensions (2D). We first present a variational formulation and rigorously prove that it preserves two fundamental geometric structures of the flows, i.e., (a) the conservation of the area enclosed by the closed curve; (b) the decrease of the perimeter of the curve. Then the variational formulation is approximated by using piecewise linear parametric finite elements in space to develop the semi-discrete scheme. With the help of the discrete Cauchy's inequality and discrete power mean inequality, the area conservation and perimeter decrease properties of the semi-discrete scheme are shown. On this basis, by combining the backward Euler method in time and a proper approximation of the unit normal vector, a structure-preserving fully discrete scheme is constructed successfully, which can preserve the two essential geometric structures simultaneously at the discrete level. Finally, numerical experiments test the convergence rate, area conservation, perimeter decrease and mesh quality, and depict the evolution of curves. Numerical results indicate that the proposed SP-PFEM provides a reliable and powerful tool for the simulation of area-conserved generalized mean curvature flow in 2D.Comment: 24 pages, 8 figure

Gender Differences in the Relationship Between Body-Esteem, Depressive Symptoms, and Academic Performance Among Adolescents

The study sought to understand the relationship between body esteem, depressive moods, and academic achievement among adolescents. No prior study examined the relationships between body esteem, depression, and academic achievement by gender. This study aimed to investigate whether gender differences exist in 1) the relationship between body esteem and academic performance, 2) the relationship between depressive symptoms and academic performance, and 3) the relationship between body esteem and depressive symptoms. The analyses yielded evidence that suggested the possibility of gender differences in the relationship between measures of body esteem and weighted GPA and in the relationship between measures of body esteem and depressive symptoms. A positive correlation between general body esteem and academic performance was found only in boys. Negative correlations between all measures of body esteem and depressive symptoms were only found in girls

Gender Differences in the Relationship Between Body-Esteem, Depressive Symptoms, and Academic Performance Among Adolescents

The study sought to understand the relationship between body esteem, depressive moods, and academic achievement among adolescents. No prior study examined the relationships between body esteem, depression, and academic achievement by gender. This study aimed to investigate whether gender differences exist in 1) the relationship between body esteem and academic performance, 2) the relationship between depressive symptoms and academic performance, and 3) the relationship between body esteem and depressive symptoms. The analyses yielded evidence that suggested the possibility of gender differences in the relationship between measures of body esteem and weighted GPA and in the relationship between measures of body esteem and depressive symptoms. A positive correlation between general body esteem and academic performance was found only in boys. Negative correlations between all measures of body esteem and depressive symptoms were only found in girls

Electrotunable liquid sulfur microdroplets.

Manipulating liquids with tunable shape and optical functionalities in real time is important for electroactive flow devices and optoelectronic devices, but remains a great challenge. Here, we demonstrate electrotunable liquid sulfur microdroplets in an electrochemical cell. We observe electrowetting and merging of sulfur droplets under different potentiostatic conditions, and successfully control these processes via selective design of sulfiphilic/sulfiphobic substrates. Moreover, we employ the electrowetting phenomena to create a microlens based on the liquid sulfur microdroplets and tune its characteristics in real time through changing the shape of the liquid microdroplets in a fast, repeatable, and controlled manner. These studies demonstrate a powerful in situ optical battery platform for unraveling the complex reaction mechanism of sulfur chemistries and for exploring the rich material properties of the liquid sulfur, which shed light on the applications of liquid sulfur droplets in devices such as microlenses, and potentially other electrotunable and optoelectronic devices

Endovascular Repair of Ascending Aortic Dissection A Novel Treatment Option for Patients Judged Unfit for Direct Surgical Repair

ObjectivesThis paper sought to report the outcomes of patients who are considered unfit for urgent surgical repair of ascending aortic dissections (AADs) who were treated using a novel endovascular repair strategy.BackgroundAAD is best treated by direct surgical repair. Patients who are unable to undergo this form of treatment have poor prognoses. Previously, clinical case reports related to endovascular repair of AAD have been controversial.MethodsBetween May 2009 and January 2011, 41 consecutive patients with AAD were treated in our institution. Fifteen patients were considered poor candidates for direct surgical repair and subsequently underwent the endovascular repair.ResultsThe nature of the referral process to our tertiary care facility made the median time from aortic dissection onset to treatment 25.5 days (range: 6 to 353 days). Dissections in 5 patients (33.3%) were considered acute, and those in 10 patients (66.7%) were considered chronic. The rate of successful stent-graft deployment was 100%, and there were no major morbidities or deaths in the perioperative period. Median follow-up was 26 months (range: 16 to 35 months). One new dissection occurred in the aortic arch at 3 months and was treated with a branched endograft. Significant enlargements of true lumens and decreases of false lumens and overall thoracic aorta were noted after the procedures.ConclusionsEndovascular repair of AAD was an appropriate treatment option in patients who were considered poor candidates for traditional direct surgical repair by the clinical criteria used in our institution. A larger series of cases with longer follow-up is needed to substantiate these results

Molecular Basis for Cooperative Binding of Anionic Phospholipids to the PH Domain of the Arf GAP ASAP1

SummaryWe have defined the molecular basis for association of the PH domain of the Arf GAP ASAP1 with phospholipid bilayers. Structures of the unliganded and dibutyryl PtdIns(4,5)P2-bound PH domain were solved. PtdIns(4,5)P2 made contact with both a canonical site (C site) and an atypical site (A site). We hypothesized cooperative binding of PtdIns(4,5)P2 to the C site and a nonspecific anionic phospholipid to the A site. PtdIns(4,5)P2 dependence of binding to large unilamellar vesicles and GAP activity was sigmoidal, consistent with cooperative sites. In contrast, PtdIns(4,5)P2 binding to the PH domain of PLC δ1 was hyperbolic. Mutation of amino acids in either the C or A site resulted in decreased PtdIns(4,5)P2-dependent binding to vesicles and decreased GAP activity. The results support the idea of cooperative phospholipid binding to the C and A sites of the PH domain of ASAP1. We propose that the mechanism underlies rapid switching between active and inactive ASAP1

Impaired colonic motility in high-glycemic diet-induced diabetic mice is associated with disrupted gut microbiota and neuromuscular function

Background: Similar to the high-fat diet (HFD), the high-glycemic diet (HGD) contributes to the development and progression of type 2 diabetes mellitus (T2DM). However, the effect of HGD on gastrointestinal motility in T2DM and its u nderlying mechanisms remain unclear. Methods: Thirty C57BL/6J mice were randomly designated into the normal-feeding diet (NFD) group, HFD group, and HGD group. The plasma glucose, plasma insulin, and gastrointestinal motility were examined. Meanwhile, the tension of isolated colonic smooth muscle rings was calculated, and the gut microbiota was analyzed by 16s rDNA high-throughput sequencing. Result: After 16 weeks of HGD feeding, obesity, hyperglycemia, insulin resistance, and constipation were observed in HGD mice. Autonomic contraction frequency of the colonic neuromuscular system and electrical field stimulation-induced contractions were reduced in HGD mice. On the contrary, neuronal nitric oxide synthase activity and neuromuscular relaxation were found to be enhanced. Finally, gut microbiota analysis revealed that Rhodospirillaceae abundance significantly increased at the family level in HGD mice. At the genus level, the abundance of Insolitispirillum increased remarkably, whereas Turicibacter abundance decreased significantly in HGD mice. Conclusion: HGD induced constipation in obese diabetic mice, which we speculated that it may be related to neuromuscular dysmotility and intestinal microbiota dysbiosis

A new opportunity for the emerging tellurium semiconductor: making resistive switching devices

Abstract: The development of the resistive switching cross-point array as the next-generation platform for high-density storage, in-memory computing and neuromorphic computing heavily relies on the improvement of the two component devices, volatile selector and nonvolatile memory, which have distinct operating current requirements. The perennial current-volatility dilemma that has been widely faced in various device implementations remains a major bottleneck. Here, we show that the device based on electrochemically active, low-thermal conductivity and low-melting temperature semiconducting tellurium filament can solve this dilemma, being able to function as either selector or memory in respective desired current ranges. Furthermore, we demonstrate one-selector-one-resistor behavior in a tandem of two identical Te-based devices, indicating the potential of Te-based device as a universal array building block. These nonconventional phenomena can be understood from a combination of unique electrical-thermal properties in Te. Preliminary device optimization efforts also indicate large and unique design space for Te-based resistive switching devices

Cofilin-1 is involved in regulation of actin reorganization during influenza A virus assembly and budding

Influenza A virus (IAV) assembly and budding on host cell surface plasma membrane requires actin cytoskeleton reorganization. The underlying molecular mechanism involving actin reorganization remains unclarified. In this study, we found that the natural antiviral compound petagalloyl glucose (PGG) inhibits F-actin reorganization in the host cell membrane during the late stage of IAV infection, which are associated with the suppression of total cofilin-1 level and its phosphorylation. Knock-down of cofilin-1 reduces viral yields. These findings provide the first evidence that cofilin-1 plays an important role in regulating actin reorganization during IAV assembly and budding