Search

A semi-empirical method is applied as a complement to the FlightStream solver, to more accurately model subsonic vortex lift over a sharp leading-edge delta wing. The method, based on the prediction of flow patterns and the application of the Polhamus method, is particularly well-adapted to a preliminary aerodynamic design phase. Within a few minutes, it can accurately predict the aerodynamic forces generated by the flow over a delta wing, which are strongly affected by the presence of a leading-edge vortex. This study presents a detailed analysis where computed results are compared against experimental data. Those were obtained from a test case of a 65° subsonic delta wing experiment (case 1), along with a sensitivity analysis against sweep angle and aspect ratio where multiple subsonic delta wings were tested (case 2). A good agreement is observed between computed data and experimental results, within pre-stall, before the vortex bursts. Analysed results demonstrate the validity of the method, for multiple wing configurations associated with different flow conditions.

TNFRSF13B encodes the transmembrane activator and CAML interactor (TACI) receptor, which drives plasma cell differentiation. Although TNFRSF13B supports host defense, dominant-negative TNFRSF13B alleles are common in humans and other species and only rarely associate with disease. We reasoned that the high frequency of disruptive TNFRSF13B alleles reflects balancing selection, the loss of function conferring advantage in some settings. Testing that concept, we investigated how a common human dominant-negative variant, TNFRSF13B A181E, imparts resistance to enteric pathogens. Mice engineered to express mono- or biallelic A144E variants of tnrsf13B, corresponding to A181E, exhibited a striking resistance to pathogenicity and transmission of Citrobacter rodentium, a murine pathogen that models enterohemorrhagic Escherichia coli, and resistance was principally owed to natural IgA deficiency in the intestine. In WT mice with gut IgA and in mutant mice reconstituted with enteric IgA obtained from WT mice, IgA induces LEE expression of encoded virulence genes, which confer pathogenicity and transmission. Taken together, our results show that C. rodentium and most likely other enteric organisms appropriated binding of otherwise protective antibodies to signal induction of the virulence program. Additionally, the high prevalence of TNFRSF13B dominant-negative variants reflects balancing selection.

Abs that neutralize SARS-CoV-2 are thought to provide the most immediate and effective treatment for those severely afflicted by this virus. Because coronavirus potentially diversifies by mutation, broadly neutralizing Abs are especially sought. Here, we report a possibly novel approach to rapid generation of potent broadly neutralizing human anti–SARS-CoV-2 Abs. We isolated SARS-CoV-2 spike protein–specific memory B cells by panning from the blood of convalescent subjects after infection with SARS-CoV-2 and sequenced and expressed Ig genes from individual B cells as human mAbs. All of 43 human mAbs generated in this way neutralized SARS-CoV-2. Eighteen of the forty-three human mAbs exhibited half-maximal inhibitory concentrations (IC50) of 6.7 × 10–12 M to 6.7 × 10–15 M for spike-pseudotyped virus. Seven of the human mAbs also neutralized (with IC50 < 6.7 × 10–12 M) viruses pseudotyped with mutant spike proteins (including receptor-binding domain mutants and the S1 C-terminal D614G mutant). Neutralization of the Wuhan Hu-1 founder strain and of some variants decreased when coding sequences were reverted to germline, suggesting that potency of neutralization was acquired by somatic hypermutation and selection of B cells. These results indicate that infection with SARS-CoV-2 evokes high-affinity B cell responses, some products of which are broadly neutralizing and others highly strain specific. We also identify variants that would potentially resist immunity evoked by infection with the Wuhan Hu-1 founder strain or by vaccines developed with products of that strain, suggesting evolutionary courses that SARS-CoV-2 could take.

TNFRSF13B encodes the “transmembrane-activator and CAML-interactor” (TACI) receptor, which drives plasma cell differentiation. Although TNFRSF13B supports host defense, dominant-negative TNFRSF13B alleles are common in humans and other species and only rarely associate with disease. We reasoned the high frequency of disruptive TNFRSF13B alleles reflects balancing selection, the loss of function conferring advantage in some settings. Testing that concept, we asked whether and how a common human dominant negative variant, TNFRSF13B A181E, imparts resistance to enteric pathogens. Mice engineered to express mono-allelic or bi-allelic A144E variants of tnrsf13B, corresponding to A181E exhibited striking resistance to pathogenicity and transmission of C. rodentium, a murine pathogen that models enterohemorrhagic E. coli, and resistance was principally owed to deficiency of natural IgA in the intestine. In wild type mice with gut IgA and in mutant mice fed IgA, binding of Ig induces expression of LEE encoded virulence genes, which confer pathogenicity and transmission. C. rodentium and probably some other enteric organisms thus appropriated binding of otherwise protective antibodies to signal induction of the virulence program and the high prevalence of TNFRSF13B dominant negative variants thus reflects balancing selection.

Electrical equipment and microprocessors distribute power and generate and/or dissipate heat due to the resistance and impedance of the various electrical components in any given circuit. That results in complications pertaining to the device functioning, failure, or damage to the component. As such, the electronic component’s temperature should be kept below a safe temperature by employing efficient thermal management system to prevent premature component failure. Numerous cooling techniques for electrical systems have been investigated such as heat sinks, direct and indirect cooing, thermoelectric coolers, and heat pipes. Traditionally, heat sinks have been notable and well-known form of electronic cooling in which they harness forced as well as natural convection to cool electronic components. On the other hand, indirect channel cooling using structured channels have been of interest for developing cooling systems for different applications. In this work, indirect air-cooling utilizing turbulence promoters in structured channel flow is investigated numerically. Numerical modeling is employed and the results are verified against experimental data in literature. Grid independence study is performed and the flow field characteristic and thermal advantage of structured ribbed channels are analyzed.

IMPACT: We devised a new method to produce highly potent SARS-CoV2-specific that can be used to treat severely ill patients with Covid-19. OBJECTIVES/GOALS: Neutralizing antibodies against SARS-CoV-2 are thought to offer the most immediate and effective treatment for those severely afflicted by Covid-19. We devised an approach for rapid and efficient generation of human monoclonal antibodies with neutralizing activity against SARS-CoV-2. METHODS/STUDY POPULATION: SARS-CoV-2 S1 spike protein-specific memory B cells were isolated from 12 subjects recovering from infection with that virus. Paired end single index sequencing was performed using up to 10,000 antigen-specific B cells per subject. Antigen-specific B cell clones were identified by unique diversity and joining gene V(D)J rearrangements and the CDR3 regions. VH and VL regions were cloned and the products expressed in 293T/17 cells to generate spike-specific human monoclonal antibodies. RESULTS/ANTICIPATED RESULTS: Forty-three human monoclonal antibodies were produced. Every monoclonal antibody so generated neutralized viruses pseudotyped with Spike protein of the Wuhan-1 strain. Eighteen monoclonal antibodies neutralized pseudotyped viruses with half-maximal inhibitory concentration (IC50s) between 1 pg/mL and 1 ng/mL (6.7 x 10E-15 M to 6.7 x 10E-12 M), exceeding by 10-100-fold the potency of previously reported anti-SARS-CoV-2-neutralizing monoclonal antibodies. Eight monoclonal antibodies neutralized viruses pseudotyped with mutant spike proteins previously identified in clinical isolates, including receptor binding domain mutants and the C-terminal D614G mutant with IC50

Transfer to and enduring expression of genes in B cells has proved a vexing challenge. We report here a novel method for the specific and durable targeting of B lymphocytes in living mice. The method involves generation of lentiviruses pseudotyped with an anti-CD19 antibody. CD19 targeting viruses injected in the spleen of living mice efficiently transduced B cells and plasma cells detected by flow cytometry analysis of GFP expression. Expression of the reporter gene could be detected in the intact animal by external imaging for more than a year and was enhanced by booster immunization. Our method thus enables the specific delivery, expression and localization by external imaging of exogenous genes to the B cells and plasma cells of living individuals.

We have developed a simple and direct method to fabricate paper-based microfluidic devices that can be used for a wide range of colorimetric assay applications. With these devices, assays can be performed within minutes to allow for quantitative colorimetric analysis by use of a widely accessible iPhone camera and an RGB color reader application (app) to measure color intensity. In the described laboratory experiment, students design and create their own microfluidic devices with common laboratory supplies such as Kimwipes, Parafilm, and a thermal laminator, and gain hands-on experience in the analysis of Fe2+ and Cu2+ by colorimetric determination.

The optimal surgical treatment of patients with transposition of the great arteries, ventricular septal defect, and pulmonary stenosis is controversial. Although the Rastelli operation has been standard surgical management of this lesion, aortic root translocation with right ventricular outflow tract (RVOT) reconstruction (Nikaidoh) and the pulmonary artery translocation (Lecompte) or REV (réparation a l'étage ventriculaire) are surgical alternatives more recently introduced to treat this complex lesion. This report reviews our 20-year experience with the Rastelli procedure and attempts to compare our outcomes with those recently published using the Nikaidoh and REV procedures.Between 1988 and 2008, 40 patients (median age, 4 years; range, 9 months to 17 years) underwent Rastelli operation at our institutions. The RVOT was obstructed in 32 and atretic in 8. Follow-up was available for all but one patient (mean follow-up, 8.6±5.6 years). The RVOT was reconstructed with homograft (n=25), bovine jugular vein (n=8), nonvalved Dacron tube (n=5), or a porcine valved conduit (n=2). Two patients required a pacemaker.There were no early, but three late deaths and one heart transplantation 12 years postoperative the Rastelli operation. Kaplan-Meier survival was 93% at 5, 10, and 20 years. Univariate risk factors for death or transplantation included surgery before 1998 (p=0.03) and concomitant noncardiac anomalies (p=0.001). Sixteen patients (40%) had reoperation for right ventricular-pulmonary artery conduit stenosis (mean, 7.8±3.8 years) without mortality. Freedom from conduit replacement was 86%, 74%, 63%, and 59% at 5, 10, 15, and 20 years, respectively. Multivariate analysis revealed that the risk factors of conduit replacement were younger age at operation (p=0.001) and surgery before 1998 (p0.001). Two patients (5%) required reoperation for left ventricular outflow tract obstruction. At follow-up, there were no sudden unexplained deaths, and New York Heart Association functional class is I or II.The Rastelli procedure is a low-risk operation with regard to early and late mortality and reoperation for left ventricular outflow tract obstruction. Conduit change operations will be required in most patients regardless of the technique of repair, but currently can be performed with low morbidity and mortality. These midterm outcomes after the Rastelli operation should serve as a basis for comparison with surgical alternatives more recently introduced for transposition of the great arteries and ventricular septal defect with RVOT obstruction.

Low Level Light Therapy (LLLT) has been implicated to stimulate tissue, promoting healing and reducing pain. One of the potential pathways stimulated by LLLT relates to the electron transport chain, where photon quantum energy can induce a change in the biochemical reactions within the cell. The aim of this study is to assess the feasibility to exploit light additionally as a diagnostic tool to determine tissue physiological states, particularly in quantifying the changes in redox states of Cytochrome C as a result of induced LLLT biochemical reactions.