79 research outputs found
The p-torsion of the Farrell—Tate cohomology of the mapping class group Γp − 1
AbstractThe mapping class group of a closed orientable surface of genus g, denoted Γg, is defined as the group of path components of the group of orientation preserving diffeomorphisms of the surface. We completely calculate the p-torsion of the Farrell-Tate cohomology of Γp − 1. The Farrell-Tate and ordinary cohomologies of Γg coincide above the virtual cohomological dimension 4g − 5.The basic method is to describe for Zp⊂Γp − 1 the quotient group N(Z / p) / Z / p as a finite extension of the pure mapping class group, where N(·) is the normalizer in Γp−1. Then putting a result of Cohen about the cohomology of the pure mapping class group into the Lyndon- Hochschild-Serre spectral sequence, we obtain the ordinary (and Farrell-Tate) cohomology of the normalizer group. The result about the p-torsion of the Farrell-Tate cohomology of Γp−1 then follows
Self-Contained In-The-Ear Devise to Deliver AAF
The design and operating characteristics of the first self-contained in-the-ear device to deliver altered auditory feedback is described for applications with those who stutter. The device incorporates a microdigital signal processor core that reproduces the high fidelity of unaided listening and auditory self-monitoring while at the same time delivering altered auditory feedback. Delayed auditory feedback and frequency-altered feedback signals in combination or isolation can be generated to the user in a cosmetically appealing custom in-the-canal and completely in-the-canal design. Programming of the device is achieved through a personal computer, interface, and fitting software. Researchers and clinicians interested in evaluating persons who stutter outside laboratory settings in a natural environment and persons who stutter looking for an alternative or adjunct to traditional therapy options are ideal candidates for this technology. In both instances an inconspicuous ear level alternative to traditional body worn devices with external microphones and earphones is offered
Robust estimation of bacterial cell count from optical density
Optical density (OD) is widely used to estimate the density of cells in liquid culture, but cannot be compared between instruments without a standardized calibration protocol and is challenging to relate to actual cell count. We address this with an interlaboratory study comparing three simple, low-cost, and highly accessible OD calibration protocols across 244 laboratories, applied to eight strains of constitutive GFP-expressing E. coli. Based on our results, we recommend calibrating OD to estimated cell count using serial dilution of silica microspheres, which produces highly precise calibration (95.5% of residuals <1.2-fold), is easily assessed for quality control, also assesses instrument effective linear range, and can be combined with fluorescence calibration to obtain units of Molecules of Equivalent Fluorescein (MEFL) per cell, allowing direct comparison and data fusion with flow cytometry measurements: in our study, fluorescence per cell measurements showed only a 1.07-fold mean difference between plate reader and flow cytometry data
Impact of COVID-19 on cardiovascular testing in the United States versus the rest of the world
Objectives: This study sought to quantify and compare the decline in volumes of cardiovascular procedures between the United States and non-US institutions during the early phase of the coronavirus disease-2019 (COVID-19) pandemic.
Background: The COVID-19 pandemic has disrupted the care of many non-COVID-19 illnesses. Reductions in diagnostic cardiovascular testing around the world have led to concerns over the implications of reduced testing for cardiovascular disease (CVD) morbidity and mortality.
Methods: Data were submitted to the INCAPS-COVID (International Atomic Energy Agency Non-Invasive Cardiology Protocols Study of COVID-19), a multinational registry comprising 909 institutions in 108 countries (including 155 facilities in 40 U.S. states), assessing the impact of the COVID-19 pandemic on volumes of diagnostic cardiovascular procedures. Data were obtained for April 2020 and compared with volumes of baseline procedures from March 2019. We compared laboratory characteristics, practices, and procedure volumes between U.S. and non-U.S. facilities and between U.S. geographic regions and identified factors associated with volume reduction in the United States.
Results: Reductions in the volumes of procedures in the United States were similar to those in non-U.S. facilities (68% vs. 63%, respectively; p = 0.237), although U.S. facilities reported greater reductions in invasive coronary angiography (69% vs. 53%, respectively; p < 0.001). Significantly more U.S. facilities reported increased use of telehealth and patient screening measures than non-U.S. facilities, such as temperature checks, symptom screenings, and COVID-19 testing. Reductions in volumes of procedures differed between U.S. regions, with larger declines observed in the Northeast (76%) and Midwest (74%) than in the South (62%) and West (44%). Prevalence of COVID-19, staff redeployments, outpatient centers, and urban centers were associated with greater reductions in volume in U.S. facilities in a multivariable analysis.
Conclusions: We observed marked reductions in U.S. cardiovascular testing in the early phase of the pandemic and significant variability between U.S. regions. The association between reductions of volumes and COVID-19 prevalence in the United States highlighted the need for proactive efforts to maintain access to cardiovascular testing in areas most affected by outbreaks of COVID-19 infection
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Molecular Basis of Interaction between Toll-like Receptor 4 and Apolipoprotein A-I Binding Protein
Inflammation is a response of immune cells to microbial pathogen-associated and host damage-associated molecular patterns. Toll-like receptor 4 (TLR4) is a major immune, pattern-recognition receptor that recognizes these ligands and initiates inflammatory signaling. Previous studies have shown that binding of Apolipoprotein A-I binding protein (AIBP) to TLR4 facilitates removal of excess cholesterol from endothelial cells and macrophages, resulting in the reduction of membrane lipid rafts and inhibition of TLR4 dimerization and reduced inflammatory responses. However, the molecular basis of interaction between TLR4 and AIBP is not fully understood. Here, I investigate TLR4 binding motifs in the AIBP molecule. Using wildtype AIBP and mutated variants of AIBP expressed and purified from a baculovirus/insect cell system, I identified a TLR4 binding domain in the AIBP molecule, which plays a critical role in regulation of TLR4-dependent inflammatory responses in microglia. My findings provide important mechanistic insights into the molecular basis of interaction between TLR4 and AIBP and may contribute to the development of AIBP-based therapy for chronic inflammatory diseases, including atherosclerosis and neuropathic pain
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Molecular Basis of Interaction between Toll-like Receptor 4 and Apolipoprotein A-I Binding Protein
Inflammation is a response of immune cells to microbial pathogen-associated and host damage-associated molecular patterns. Toll-like receptor 4 (TLR4) is a major immune, pattern-recognition receptor that recognizes these ligands and initiates inflammatory signaling. Previous studies have shown that binding of Apolipoprotein A-I binding protein (AIBP) to TLR4 facilitates removal of excess cholesterol from endothelial cells and macrophages, resulting in the reduction of membrane lipid rafts and inhibition of TLR4 dimerization and reduced inflammatory responses. However, the molecular basis of interaction between TLR4 and AIBP is not fully understood. Here, I investigate TLR4 binding motifs in the AIBP molecule. Using wildtype AIBP and mutated variants of AIBP expressed and purified from a baculovirus/insect cell system, I identified a TLR4 binding domain in the AIBP molecule, which plays a critical role in regulation of TLR4-dependent inflammatory responses in microglia. My findings provide important mechanistic insights into the molecular basis of interaction between TLR4 and AIBP and may contribute to the development of AIBP-based therapy for chronic inflammatory diseases, including atherosclerosis and neuropathic pain
Kinetic Study of Bisphenol A Migration from Low-Density Polyethylene Films into Food Simulants
Migration
testing of bisphenol A (BPA) from low-density polyethylene
(LDPE) into food simulants was performed as a function of three factors:
temperature, initial BPA concentration, and food simulant type. An
HPLC–UV method was applied to measure the amount of BPA that
migrated into the solvents. The migration process was described by
Fick’s diffusion equation, and the migration parameters such
as the diffusion coefficient (<i>D</i>) were derived from
the equation. <i>D</i> values ranged from 10<sup>–10</sup> to 10<sup>–8</sup> cm<sup>2</sup> s<sup>–1</sup> under
different migration conditions. Statistical analysis showed that the
single factors had significant effects on <i>D</i>, but
among the interaction effects only the temperature-simulant interaction
was significant. The dependence of <i>D</i> on temperature
followed an Arrhenius-type relationship, with the activation energy
(<i>E</i><sub>a</sub>) ranging from 112.8 ± 1.6 kJ
mol<sup>–1</sup> to 128.9 ± 4.3 kJ mol<sup>–1</sup> for the three food simulants. An exponential relationship was found
between the diffusion coefficient and initial BPA concentration for
each food simulant. BPA migration into different food simulants was
influenced by the affinity between the polymer and the solvent, and
better affinity may reduce the diffusion rate of BPA
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