Numerical simulation of an air-supported structure in the air flow

Wind load is often the critical load for air-supported structures. For example, high wind demolished an air-supported tennis court roof in Zhulebino district of Moscow on May 29, 2017. Aerodynamic instability (buffeting, flutter, etc.) can produce excessive slack regions and extremely large deflections. That is why the coupled analysis should be carried out to understanding aeroelastic behavior of air-supported structures under wind loads. The technique of the nonlinear numerical analysis of air-supported structures including fluidstructural interaction (FSI) has been described in the present paper. Numerical simulation of the tunnel test of large-scale air-supported model has been carried out as an example of using this technique. Wind tunnel study is described in the papers1, 2. Experimental deformed shape, pressure coefficients and aerodynamic forces were compared with the results of presented numerical simulation. Computations were carried out with using of commercial code ANSYS 15.0. Some difficulties appeared during simulation process are discussed. An applicability of the proposed technique to the considered problem was confirmed by a good agreement of the experimental and numerical results. Both methods showed that surface wind loads can increase due to deformation of a structure. These conclusions emphasize the importance of researches on wind interaction with air-supported structures

CD4 T Cells Treated with gp120 Acquire a CD45R0+/CD45RA+ Phenotype

HIV-infected patients exhibit quantitative and qualitative defects in CD4 T cells, including having increased numbers of CD4+CD45R0+/CD45RA+ T cells, although it remains unclear how these cells arise. Here we demonstrate that gp120 treatment of activated but not resting primary human CD4 T cells decreases number of cells with single positive CD45R0+/CD45RA- effector memory phenotype while proportionally increasing the subset of cells with double positive CD45R0+/CD45RA+ mixed phenotype. We found that double positive CD45R0+/CD45RA+CD4 T cells preferentially undergo apoptosis while single positive CD45R0+/CD45RA- and CD45R0-/CD45RA+ do not. Blocking gp120-CD4 interaction with sCD4 or inhibition Lck activity reverses gp120 induced increase in double positive CD45R0+/CD45RA+CD4 T cells and subsequently diminishes the apoptosis of double positive CD45R0+/CD45RA+ cells. Altogether these data indicate that gp120 ligation of the CD4 receptor increases the number of double positive CD45R0+/CD45RA+ CD4 T cells which subsequently undergo apoptosis in a CD4 dependent manner

Altered brain energetics induces mitochondrial fission arrest in Alzheimer's Disease.

Altered brain metabolism is associated with progression of Alzheimer's Disease (AD). Mitochondria respond to bioenergetic changes by continuous fission and fusion. To account for three dimensional architecture of the brain tissue and organelles, we applied 3-dimensional electron microscopy (3D EM) reconstruction to visualize mitochondrial structure in the brain tissue from patients and mouse models of AD. We identified a previously unknown mitochondrial fission arrest phenotype that results in elongated interconnected organelles, "mitochondria-on-a-string" (MOAS). Our data suggest that MOAS formation may occur at the final stages of fission process and was not associated with altered translocation of activated dynamin related protein 1 (Drp1) to mitochondria but with reduced GTPase activity. Since MOAS formation was also observed in the brain tissue of wild-type mice in response to hypoxia or during chronological aging, fission arrest may represent fundamental compensatory adaptation to bioenergetic stress providing protection against mitophagy that may preserve residual mitochondrial function. The discovery of novel mitochondrial phenotype that occurs in the brain tissue in response to energetic stress accurately detected only using 3D EM reconstruction argues for a major role of mitochondrial dynamics in regulating neuronal survival

HIV gp120 Induces, NF-κB Dependent, HIV Replication that Requires Procaspase 8

HIV envelope glycoprotein gp120 causes cellular activation resulting in anergy, apoptosis, proinflammatory cytokine production, and through an unknown mechanism, enhanced HIV replication.We describe that the signals which promote apoptosis are also responsible for the enhanced HIV replication. Specifically, we demonstrate that the caspase 8 cleavage fragment Caspase8p43, activates p50/p65 Nuclear Factor kappaB (NF-kappaB), in a manner which is inhibited by dominant negative IkappaBalpha. This caspase 8 dependent NF-kappaB activation occurs following stimulation with gp120, TNF, or CD3/CD28 crosslinking, but these treatments do not activate NF-kappaB in cells deficient in caspase 8. The Casp8p43 cleavage fragment also transactivates the HIV LTR through NF-kappaB, and the absence of caspase 8 following HIV infection greatly inhibits HIV replication.Gp120 induced caspase 8 dependent NF-kappaB activation is a novel pathway of HIV replication which increases understanding of the biology of T-cell death, as well as having implications for understanding treatment and prevention of HIV infection

Infected Cell Killing by HIV-1 Protease Promotes NF-κB Dependent HIV-1 Replication

Acute HIV-1 infection of CD4 T cells often results in apoptotic death of infected cells, yet it is unclear what evolutionary advantage this offers to HIV-1. Given the independent observations that acute T cell HIV-1 infection results in (1) NF-κB activation, (2) caspase 8 dependent apoptosis, and that (3) caspase 8 directly activates NF-κB, we questioned whether these three events might be interrelated. We first show that HIV-1 infected T cell apoptosis, NF-κB activation, and caspase 8 cleavage by HIV-1 protease are coincident. Next we show that HIV-1 protease not only cleaves procaspase 8, producing Casp8p41, but also independently stimulates NF-κB activity. Finally, we demonstrate that the HIV protease cleavage of caspase 8 is necessary for optimal NF-κB activation and that the HIV-1 protease specific cleavage fragment Casp8p41 is sufficient to stimulate HIV-1 replication through NF-κB dependent HIV-LTR activation both in vitro as well as in cells from HIV infected donors. Consequently, the molecular events which promote death of HIV-1 infected T cells function dually to promote HIV-1 replication, thereby favoring the propagation and survival of HIV-1

Partial inhibition of mitochondrial complex I ameliorates Alzheimer\u27s disease pathology and cognition in APP/PS1 female mice.

Alzheimer\u27s Disease (AD) is a devastating neurodegenerative disorder without a cure. Here we show that mitochondrial respiratory chain complex I is an important small molecule druggable target in AD. Partial inhibition of complex I triggers the AMP-activated protein kinase-dependent signaling network leading to neuroprotection in symptomatic APP/PS1 female mice, a translational model of AD. Treatment of symptomatic APP/PS1 mice with complex I inhibitor improved energy homeostasis, synaptic activity, long-term potentiation, dendritic spine maturation, cognitive function and proteostasis, and reduced oxidative stress and inflammation in brain and periphery, ultimately blocking the ongoing neurodegeneration. Therapeutic efficacy in vivo was monitored using translational biomarkers FDG-PET, 31P NMR, and metabolomics. Cross-validation of the mouse and the human transcriptomic data from the NIH Accelerating Medicines Partnership-AD database demonstrated that pathways improved by the treatment in APP/PS1 mice, including the immune system response and neurotransmission, represent mechanisms essential for therapeutic efficacy in AD patients