Direct Numerical Simulation of Receptivity to Roughness in a Swept-Wing Boundary Layer at High Reynolds Numbers

Direct numerical simulations (DNS) are performed to examine the receptivity to roughness in a spatially developing three-dimensional boundary layer over an in finite-swept natural-laminar-flow wing at a free stream Mach number of 0:75 and a chord Reynolds number of approximately 25 million based on the long, swept chord. Stationary cross ow disturbances are excited by applying either critically spaced discrete cylinders of micron size or naturally occurring distributed roughness in the leading-edge region. The DNS data show that the spanwise spectral content of the excited cross ow disturbances is highly dependent upon the shape of roughness elements, and the initial growth of the cross ow structures is a nonlinear function of the element height. The linear growth rate of the excited cross ow disturbances predicted by DNS shows good agreement with linear parabolized stability equations. The receptivity study lays the foundation for investigating the stabilization of the naturally most unstable steady cross ow mode by using spanwise periodic DREs

Salvage of a failed open gastrocutaneous fistula repair with an endoscopic over-the-scope clip

AbstractOnce enteral access via gastrostomy tube (G-tube) is no longer indicated, the tube is typically removed in clinic with a high probability of spontaneous closure. When spontaneous closure is not achieved, the formation of a gastrocutaneous fistula (GCF) is possible. The incidence of GCF is directly related with the length of time the tube has been placed. When conservative management fails, surgical intervention is the standard treatment. Endoscopic techniques have been described for primary closure of GCF in adults including banding and cauterizing of the fistula tract with placement of a standard endoscopic clip. Over-the-scope clips (OTSC) have recently been reported in primary GCF closure in children (Wright et al., 2015). In patients with skin irritation surrounding a GCF making surgical repair difficult, endoscopic OTSC closure provides particular benefit. It is our belief that this is the first case report of endoscopically salvaging a leak from a failed open GCF repair

Proteomic analysis of secretagogue-stimulated neutrophils implicates a role for actin and actin-interacting proteins in Rac2-mediated granule exocytosis

<p>Abstract</p> <p>Background</p> <p>Neutrophils are abundant leukocytes that play a primary role in defence against pathogens. Neutrophils enter sites of infection where they eliminate pathogens via phagocytosis and the release of antimicrobial mediators via degranulation. Rho GTPases, particularly Rac2, play a key role in neutrophil degranulation. The purpose of this study was to identify Rac2-dependent changes in protein abundance in stimulated neutrophils.</p> <p>Methods</p> <p>We performed a proteomic analysis on secretagogue-stimulated bone marrow neutrophils that were isolated from wild-type and Rac2^-/-mice. Protein abundance was analyzed by 2-dimensional SDS-PAGE of fluorescently labelled samples which allowed the detection ~3500 proteins.</p> <p>Results</p> <p>We identified 22 proteins that showed significant changes in abundance after secretagogue-stimulation of wild-type neutrophils, which did not occur in neutrophils isolated from Rac2^-/-mice. As expected, the abundance of several granule proteins was reduced in wild-type cells; this did not occur in Rac2^-/-neutrophils which confirms the requirement for Rac2 in degranulation. We also found changes in abundance of many actin remodelling proteins including coronin-1A, β-actin and the F-actin capping protein, (CapZ-β). Coronin-1A showed elevated levels of several isoforms after stimulation of neutrophils from wild-type, but not from Rac2^-/-mice. These isoforms were immunoreactive with anti-phospho-threonine antibodies, suggesting that neutrophil stimulation triggers a Rac2-dependent kinase cascade that results in the phosphorylation of coronin-1A.</p> <p>Conclusion</p> <p>The control of Rac2-mediated degranulation in neutrophils likely functions through actin remodelling via activation of several actin-binding proteins. We found coronin-1A to be a novel downstream effector protein of this pathway that is threonine phosphorylated in response to secretagogue stimulation.</p

Comparative study of hybrid artificial intelligence approaches for predicting peak shear strength along soil-Geocomposite drainage layer interfaces

Peak shear strength of soil-Geocomposite Drain Layer (GDL) interfaces is an important parameter in the designing and operating related engineering structures. In this paper, a database compiled from 316 large direct shear tests on soil-GDL interfaces has been established. Based on this database, five different machine learning models: Back Propagation Artificial Neural Network (BPANN) and Support Vector Machine (SVM), with hyperparameters optimised by Particle Swarm Optimisation Algorithm (PSO) and Genetic Algorithm (GA), respectively, and Extreme Learning Machine (ELM) optimised by Exhaustive Method, were adopt to assess the peak shear strength of soil-GDL interfaces. Then, a comprehensive investigation and comparison of the predictive performance for the models was conducted. Also, based on the selected optimal machine learning model, sensitivity analysis was conducted, and an empirical equation developed based on it. The research indicated that GA and PSO could significantly increase forecasting precision in a small number of iterations. The BPANN model optimised by PSO has the highest forecasting precision based on the statistics criteria: Root-Mean-Square Error, Correlation Coefficient, Coefficient of Determination, Wilmot’s Index of Agreement, and Mean Absolute Percentage Error. The normal stress has the biggest impact on the peak shear strength, followed by drainage core type, moisture saturation of the soil layer, shearing surface, soil type, consolidation condition, geotextile specification, soil density and drainage core thickness, and the ranking is affected partly by the data distribution of input parameters in the database based on mechanism analysis. An empirical equation developed from the optimal model was proposed to estimate the peak shear strength, which provides convenience for geotechnical engineering personnel with limited knowledge of machine learning technique

Polarimetric Imaging using Two Photoelastic Modulators

A method of polarimetric imaging, now undergoing development, involves the use of two photoelastic modulators in series, driven at equal amplitude but at different frequencies. The net effect on a beam of light is to cause (1) the direction of its polarization to rotate at the average of two excitation frequencies and (2) the amplitude of its polarization to be modulated at the beat frequency (the difference between the two excitation frequencies). The resulting modulated optical light beam is made to pass through a polarizing filter and is detected at the beat frequency, which can be chosen to equal the frame rate of an electronic camera or the rate of sampling the outputs of photodetectors in an array. The method was conceived to satisfy a need to perform highly accurate polarimetric imaging, without cross-talk between polarization channels, at frame rates of the order of tens of hertz. The use of electro-optical modulators is necessitated by a need to obtain accuracy greater than that attainable by use of static polarizing filters over separate fixed detectors. For imaging, photoelastic modulators are preferable to such other electrio-optical modulators as Kerr cells and Pockels cells in that photoelastic modulators operate at lower voltages, have greater angular acceptances, and are easier to use. Prior to the conception of the present method, polarimetric imaging at frame rates of tens of hertz using photoelastic modulators was not possible because the resonance frequencies of photoelastic modulators usually lie in the range from about 20 to about 100 kHz

Type 1 Diabetes in the BB Rat: A Polygenic Disease

OBJECTIVE-Two type 1 diabetes susceptibility genes have been identified in the spontaneously diabetic biobreeding diabetes-prone (BBDP) rat, the major histocompatibility complex (MHC) (RT1) class II u haplotype (Iddm1) and Gimap5 (Iddm2). The strong effects of these have impeded previous efforts to map additional loci. We tested the hypothesis that type 1 diabetes is a polygenic disease in the BBDP rat. RESEARCH DESIGN AND METHODS-We performed the most comprehensive genome-wide linkage analysis for type 1 diabetes, age of disease onset (AOO), and insulitis subpheno- types in 574 F2 animals from a cross-intercross between BBDP and type 1 diabetes-resistant, double congenic ACI.BBDP- RT1u,Gimap5 (ACI.BB 1ulyp) rats, where both Iddm1 and Iddm2 were fixed as BBDP. RESULTS-A total of 19% of these F2 animals developed type 1 diabetes, and eight type 1 diabetes susceptibility loci were mapped, six showing significant linkage (chromosomes 1, 3, 6 [two loci], 12, and 14) and two (chromosomes 2 and 17) suggestive linkage. The chromosomes 6, 12, and 14 intervals were also linked to the severity of islet infiltration by immunocytes, while those on chromosomes 1, 6 (two loci), 14, 17, and a type 1 diabetes-unlinked chromosome 8 interval showed significant linkage to the degree of islet atrophy. Four loci exhibited suggestive linkage to AOO on chromosomes 2 (two loci), 7, and 18 but were unlinked to type 1 diabetes. INS, PTPN22, IL2/IL21, C1QTNF6, and C12orf30, associated with human type 1 diabetes, are contained within the chromosomes 1, 2, 7, and 12 loci. CONCLUSIONS-This study demonstrates that the BBDP diabetic syndrome is a complex, polygenic disease that may share additional susceptibility genes besides MHC class II with human type 1 diabetes

Pressure anisotropy in global magnetospheric simulations: A magnetohydrodynamics model

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/95331/1/jgra22024.pd

Role of Acid Sphingomyelinase in Shifting the Balance Between Proinflammatory and Reparative Bone Marrow Cells in Diabetic Retinopathy

The metabolic insults associated with diabetes lead to low-grade chronic inflammation, retinal endothelial cell damage, and inadequate vascular repair. This is partly due to the increased activation of bone marrow (BM)-derived proinflammatory monocytes infiltrating the retina, and the compromised function of BM-derived reparative circulating angiogenic cells (CACs), which home to sites of endothelial injury and foster vascular repair. We now propose that a metabolic link leading to activated monocytes and dysfunctional CACs in diabetes involves upregulation of a central enzyme of sphingolipid signaling, acid sphingomyelinase (ASM). Selective inhibition of ASM in the BM prevented diabetes-induced activation of BM-derived microglia-like cells and normalized proinflammatory cytokine levels in the retina. ASM upregulation in diabetic CACs caused accumulation of ceramide on their cell membrane, thereby reducing membrane fluidity and impairing CAC migration. Replacing sphingomyelin with ceramide in synthetic membrane vesicles caused a similar decrease in membrane fluidity. Inhibition of ASM in diabetic CACs improved membrane fluidity and homing of these cells to damaged retinal vessels. Collectively, these findings indicate that selective modulation of sphingolipid metabolism in BM-derived cell populations in diabetes normalizes the reparative/proinflammatory cell balance and can be explored as a novel therapeutic strategy for treating diabetic retinopathy

Postpartum Mastitis and Community-acquired Methicillin-resistant Staphylococcus aureus

This single-center, case-control study documents a relative increase in methicillin resistance among 48 cases of Staphylococcus aureus–associated postpartum mastitis during 1998–2005. Of 21 cases with methicillin resistance, 17 (81%) occurred in 2005. Twenty (95%) isolates contained the Staphylococcus cassette chromosome mec type IV gene; this suggests that the increase is due to community-acquired methicillin-resistant Staphylococcus aureus