Changes in lamellar arrangement of crystalline and flexible fluorinated transparent films with drawing

In recent times, a “crystalline” and flexible optical waveguide candidate with excellent heat‐resistance and dimensional stability are developed. For the practical use of this crystalline optical film in the near future, an accurate control of the solid‐state structure is indispensable because of the necessity of reducing light refraction at the crystalline/amorphous interface. In this study, changes in the fine structure and lamella arrangement upon drawing poly[tetrafluoroethylene‐co‐(perfluoroethylvinylether)] (EFA) transparent crystalline films were investigated by using wide‐angle X‐ray diffraction (WAXD) and small‐angle X‐ray scattering (SAXS) methods. The EFA was crystallized as a lamella crystal in the films and formed a thicker lamella. Upon the drawing of the EFA films, four‐point SAXS diagrams developed in the photograph at through direction to the film, which implied that a particular type of layer structure, an alternately tilted lamella arrangement known as the herringbone, was formed. From the result of WAXD and SAXS measurements at edge direction to the film, it is found that formation of isotropic disordered lamella arrangement. Therefore, it is indicated that three‐dimensional lamella arrangement in this fluorinated transparent film forms uniaxially cylindrical symmetry. POLYM. ENG. SCI., 2010. © 2010 Society of Plastics Engineers     

Viral Infection and Cardiovascular Disease: Implications for the Molecular Basis of COVID-19 Pathogenesis

The current pandemic of coronavirus disease 2019 (COVID-19) is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). While this respiratory virus only causes mild symptoms in younger healthy individuals, elderly people and those with cardiovascular diseases such as systemic hypertension are susceptible to developing severe conditions that can be fatal. SARS-CoV-2 infection is also associated with an increased incidence of cardiovascular diseases such as myocardial injury, acute coronary syndrome, and thromboembolism. Understanding the mechanisms of the effects of this virus on the cardiovascular system should thus help develop therapeutic strategies to reduce the mortality and morbidity associated with SARS-CoV-2 infection. Since this virus causes severe and fatal conditions in older individuals with cardiovascular comorbidities, effective therapies targeting specific populations will likely contribute to ending this pandemic. In this review article, the effects of various viruses—including other coronaviruses, influenza, dengue, and human immunodeficiency virus—on the cardiovascular system are described to help provide molecular mechanisms of pathologies associated with SARS-CoV-2 infection and COVID-19. The goal is to provide mechanistic information from the biology of other viral infections in relation to cardiovascular pathologies for the purpose of developing improved vaccines and therapeutic agents effective in preventing and/or treating the acute and long-term consequences of SARS-CoV-2 and COVID-19.     

Reduction of Superoxide Dismutase 1 Delays Regeneration of Cardiotoxin-Injured Skeletal Muscle in KK/Ta-Ins2Akita Mice with Progressive Diabetic Nephropathy

Superoxide dismutase (SOD) is a major antioxidant enzyme for superoxide removal, and cytoplasmic SOD (SOD1) is expressed as a predominant isoform in all cells. We previously reported that renal SOD1 deficiency accelerates the progression of diabetic nephropathy (DN) via increasing renal oxidative stress. To evaluate whether the degree of SOD1 expression determines regeneration capacity and sarcopenic phenotypes of skeletal muscles under incipient and advanced DN conditions, we investigated the alterations of SOD1 expression, oxidative stress marker, inflammation, fibrosis, and regeneration capacity in cardiotoxin (CTX)-injured tibialis anterior (TA) muscles of two Akita diabetic mouse models with different susceptibility to DN, DN-resistant C57BL/6-Ins2^Akita and DN-prone KK/Ta-Ins2^Akita mice. Here, we report that KK/Ta-Ins2^Akita mice, but not C57BL/6-Ins2^Akita mice, exhibit delayed muscle regeneration after CTX injection, as demonstrated by the finding indicating significantly smaller average cross-sectional areas of regenerating TA muscle myofibers relative to KK/Ta-wild-type mice. Furthermore, we observed markedly reduced SOD1 expression in CTX-injected TA muscles of KK/Ta-Ins2^Akita mice, but not C57BL/6-Ins2^Akita mice, along with increased inflammatory cell infiltration, prominent fibrosis and superoxide overproduction. Our study provides the first evidence that SOD1 reduction and the following superoxide overproduction delay skeletal muscle regeneration through induction of overt inflammation and fibrosis in a mouse model of progressive DN.     

Finite element analysis on global and local estimation for thermo-mechanical response of EPL wafer heating

In this paper, an approach is presented for the computation of the in-plane pattern placement error (PPE) caused by the wafer heating during exposure of electron projection lithography (EPL) using the finite element method (FEM), which is one of candidates in the next-generation lithography (NGL) exposure tools. The PPE is the global and local distortion, and is the thermo-mechanical response due to the thermal deformation of the wafer in the lithography process. The prediction of PPE requires high accuracy for NGL exposure tools. The simultaneous estimation of the global and local PPE to the whole wafer of a full three-dimensional FE model using a solid element requires excessive computation time. A novel technique of numerical simulation is developed and proposed, which is the employment of a shell element combined with previously proposed the dynamic meshing technique (DMT), being possible to predict PPE in realistic computation time with high accuracy. Simulations are performed for the wafer heating of EPL effectively using three techniques, that is the equivalent average heating technique and two proposed techniques. The simulation results agree closely with the result of a full three-dimensional FE analysis, and the required computation time becomes 1/16 or much less of that.     

Effects of heat and water transport on the performance of polymer electrolyte membrane fuel cell under high current density operation

Key challenges to the acceptance of polymer electrolyte membrane fuel cells (PEMFCs) for automobiles are the cost reduction and improvement in its power density for compactness. In order to get the solution, the further improvement in a fuel cell performance is required. In particular, under higher current density operation, water and heat transport in PEMFCs has considerable effects on the cell performance. In this study, the impact of heat and water transport on the cell performance under high current density was investigated by experimental evaluation of liquid water distribution and numerical validation. Liquid water distribution in MEA between rib and channel area is evaluated by neutron radiography. In order to neglect the effect of liquid water in gas channels and reactant species concentration distribution in the flow direction, the differential cell was used in this study. Experimental results suggested that liquid water under the channel was dramatically changed with rib/channel width. From the numerical study, it is found that the change of liquid water distribution was significantly affected by temperature distribution in MEA between rib and channel area. In addition, not only heat transport but also water transport through the membrane also significantly affected the cell performance under high current density operation.     

para-Selectivity of silicalite-1 coated MFI type galloaluminosilicate in aromatization of light alkanes

Journal of Porous Materials - MFI type galloaluminosilicates (GaAlMFI) were coated with inert silicalite-1 layers. The silicalite-1 coating could improve the para-selectivity for xylene production...     

Damage monitoring of CFRP stiffened panels under compressive load using FBG sensors

FBG sensors were embedded in each of two CFRP stiffened panels fabricated by VaRTM. Low-velocity impacts were applied to one of the panels in order to compare the methods of monitoring impact events using FBG sensors. The main impact damage was an interlaminar delamination inside the skin, which could be observed by an ultrasonic C-scan. A monitoring method using the full spectral signals was more effective in evaluating the impact damages in detail than that using the center wavelength. Following the impact tests, buckling behaviors were investigated under compressive loading using FBG sensors and surface-attached strain gauges. The FBG sensors could evaluate strain changes resulting from buckling behaviors under relatively low compressive loading. They could also evaluate damage growth until the final failure and difference of buckling behaviors between panels with and without impact damages.     

Collision-activated infrared multiphoton dissociation in a quadrupole ion trap mass spectrometer

We propose and demonstrate a new method for multiple-stage mass spectrometry (MSn), collision-activated infrared multiphoton dissociation (CA-IRMPD), which is very effective for the quadrupole ion trap mass spectrometer (QITMS). CA-IRMPD uses a combination of focused laser irradiation (beam radius, approximately 0.4 mm) and collisional activation by a supplemental AC voltage between endcap electrodes. This combination enables IRMPD, which has conventionaLly been ineffective above 10(-4) Torr, to be used under a standard bath gas pressure of 2-8 mTorr. CA-IRMPD can produce richer spectra of product ions than CID or IRMPD while maintaining high sensitivity and mass resolution; thus, it will contribute to an accurate determination of peptide sequences.     

Porous plug and superfluid helium film flow suppressor for the soft X-ray spectrometer onboard Astro-H

Suppression of superfluid helium flow is critical for the Soft X-ray Spectrometer (SXS) onboard Astro-H, to achieve a life time of the liquid helium over 5 years. The superfluid film flow must be sufficiently small, compared to a nominal helium gas flow rate of the SXS . For this purpose, four devices composed of a porous plug, an orifice, a heat exchanger, and knife edge devices will be employed based on the experience of the X-ray microcalorimeter (XRS for X-Ray Spectrometer) onboard Suzaku. The porous plug is a phase separator of the liquid and gas helium. A potential film flow leaking from the porous plug is suppressed by the orifice. Almost all the remaining film flow evaporates at the heat exchanger. The knife edge devices stop the remaining film flow by using atomically sharp edges. In this paper, we describe the principle and design of these four devices.