Seasonal Energy Efficiency Rating Improvement Of Residential HVAC Systems Using A Low Power Inverter With A PSC Compressor

Homeowners in the United States can generally choose among three types of air conditioning systems: fixed-speed compressor systems that cycle on and off to deliver an average cooling capacity; fixed-speed / multi-capacity compressor systems with reduced cycling; and variable speed compressor systems that match the cooling load of the household, thereby delivering better temperature and humidity control with higher efficiency and comfort levels. While HVAC systems account for about 45% of the energy consumption in U.S. homes and variable speed compressor systems can achieve significantly higher efficiency, they only account for 10% of the market and systems installed in new buildings mostly remain single speed. This could be explained in part by the initial system cost and the complex electronic circuitry used to vary compressor speed. This paper presents a system solution to improve the Seasonal Energy Efficiency Rating (SEER) of Permanent Split Capacitor (PSC) compressor systems by introducing a low power inverter used only for operation at low capacities. SEER results for 3 tons and 5 tons systems with scroll and rotary compressors are presented. The impact of varying the speed of the PSC outdoor fan on SEER is also discussed

Ectopic A-lattice seams destabilize microtubules

Natural microtubules typically include one A-lattice seam within an otherwise helically symmetric B-lattice tube. It is currently unclear how A-lattice seams influence microtubule dynamic instability. Here we find that including extra A-lattice seams in GMPCPP microtubules, structural analogues of the GTP caps of dynamic microtubules, destabilizes them, enhancing their median shrinkage rate by >20-fold. Dynamic microtubules nucleated by seeds containing extra A-lattice seams have growth rates similar to microtubules nucleated by B-lattice seeds, yet have increased catastrophe frequencies at both ends. Furthermore, binding B-lattice GDP microtubules to a rigor kinesin surface stabilizes them against shrinkage, whereas microtubules with extra A-lattice seams are stabilized only slightly. Our data suggest that introducing extra A-lattice seams into dynamic microtubules destabilizes them by destabilizing their GTP caps. On this basis, we propose that the single A-lattice seam of natural B-lattice MTs may act as a trigger point, and potentially a regulation point, for catastrophe

Social media policies at US medical schools

Background/Purpose: Today's medical students are learning in a social media era in which patient confidentiality is at risk yet schools’ social media policies have not been elucidated. The purpose of this study is to describe the presence of medical schools on top social media sites and to identify whether student policies for these schools explicitly address social media use. Method: Websites of all 132 accredited US medical schools were independently assessed by two investigators for their presence (as of March 31, 2010) on the most common social networking and microblogging sites (Facebook and Twitter) and their publicly available policies addressing online social networking. Key features from these policies are described. Results: 100% (n=132) of US medical schools had websites and 95.45% (126/132) had any Facebook presence. 25.76% (34/132) had official medical school pages, 71.21% (94/132) had student groups, and 54.55% (72/132) had alumni groups on Facebook. 10.6% of medical schools (14/132) had Twitter accounts. 128 of 132 medical schools (96.97%) had student guidelines or policies publicly available online. 13 of these 128 schools (10.16%) had guidelines/policies explicitly mentioning social media. 38.46% (5/13) of these guidelines included statements that defined what is forbidden, inappropriate, or impermissible under any circumstances, or mentioned strongly discouraged online behaviors. 53.85% (7/13) encouraged thoughtful and responsible social media use. Conclusions: Medical schools and their students are using social media. Almost all US medical schools have a Facebook presence, yet most do not have policies addressing student online social networking behavior. While social media use rises, policy informing appropriate conduct in medical schools lags behind. Established policies at some medical schools can provide a blueprint for others to adopt and adapt

Leading-twist pion and kaon distribution amplitudes in the gauge-invariant nonlocal chiral quark model from the instanton vacuum

We investigate the leading-twist light-cone distribution amplitudes for the pion and kaon based on the gauge-invariant nonlocal chiral quark model from the instanton vacuum in the presence of external axial-vector currents. We find that the nonlocal contribution from the gauge invariance has much effects on the pion distribution amplitudes, while it changes mildly the kaon ones. We also study the Gegenbauer moments of the distribution amplitudes and compare them with the empirical analysis of the CLEO data.Comment: 14 pages, 10 figure

Bone mass and microarchitecture of irradiated and bone marrow-transplanted mice: influences of the donor strain

Summary Total body irradiation and bone marrow transplantation induced dramatic trabecular bone loss and cortical thickening in mice. Transplanted cells were engrafted in bone marrow, along trabeculae, and in periosteal and endosteal envelopes. None of the osteocytes were of donor origin. Bone microarchitecture of transplanted mice changed to tend toward the donor phenotype. Introduction Osteopenia and osteoporosis are complications of bone marrow transplants (BMT) attributed to related chemotherapy. However, the specific influence of total body irradiation (TBI) is unknown. Methods We investigated the effects of TBI and BMT on bone mass and microarchitecture by micro-CT. Eighteen C57Bl/6 (B6) mice receiving lethal TBI had a BMT with marrow cells from green fluorescent protein--transgenic-C57Bl/6 (GFP) mice. Transplanted (TGFPB6), B6, and GFP mice were euthanized 1, 3, and 6 months after BMT or at a related age. Results TGFPB6 presented a dramatic bone loss compared with B6 and did not restore their trabecular bone mass over time, despite a cortical thickening 6 months after BMT. Serum testosterone levels were not significantly reduced after BMT. During aging, GFP mice have less trabeculae, thicker cortices, but a narrower femoral shaft than B6 mice. From 3 months after BMT, cortical characteristics of TGFPB6 mice differed statistically from B6 mice and were identical to those of GFP mice. GFP+ cells were located along trabecular surfaces and in periosteal and endosteal envelopes, but none of the osteocytes expressed GFP. Conclusion Our findings suggest that engrafted cells did not restore the irradiation-induced trabecular bone loss, but reconstituted a marrow microenvironment and bone remodeling similar to those of the donor. The effects of irradiation and graft on bone remodeling differed between cortical and trabecular bone

Evaluating Diversity and Inclusion Content on Graduate Medical Education Websites.

UNLABELLED: Websites are important tools for programs to provide future residency applicants with freely accessible information regarding their program, including diversity, equity, and inclusion (DEI) initiatives. OBJECTIVE: To describe the variability of DEI content in residency programs and compare DEI website content by specialty. METHODS: Using the 2021 Accreditation Council for Graduate Medical Education (ACGME) list of residency programs, residency training websites were identified and evaluated. Information was extracted from program websites as indicators of DEI content. Chi-square analysis and one-way ANOVA were chosen to assess for statistical differences. RESULTS: In total, 4644 program websites representing 26 specialties were assessed. Among all the programs, the average DEI completeness of a program website was 6.1±14.6% (range 0-100%). While 6.2% of all programs had a diversity webpage, only 13.3% included a commitment to DEI, and few programs (2.7%) provided information about underrepresented in medicine (URiM) faculty. CONCLUSIONS: Graduate medical education programs can enhance information for current and prospective applicants about DEI initiatives on their websites. Including DEI initiatives on residency websites may improve diversity recruitment efforts

ASSESSMENT OF THE ADSORPTION OF AEROMONAS HYDROPHILA ON POLYTHENE IN SODIUM HYPOCHLORITE AND HYDROGEN PEROXIDE TREATED WATER

A study was carried out on Aeromonas hydrophila adhesion to polythene fragment at different cell growth phases in aquatic microcosm. The main purpose of this study was to assess adsorption capacity, adsorption intensity and kinetics of Aeromonas hydrophila on polythene in sodium hypochlorite (NaOCl) and hydrogen peroxide (H2O2) disinfected water. The mean abundance of adhered A. hydrophila sometimes reached 28 and 111CFU.cm-2 respectively in NaOCl and H2O2 treated water. The adsorption capacities of A. hydrophila cells fluctuated between 1 and 2.12x1057 and between 1 and 2.29x1027 adhered cells.cm-2 in NaOCl and H2O2 disinfected water respectively. The adsorption intensities of this bacterium ranged from -45.81 to 3.49x1019 and from 0.16 to 2.29x1027 respectively in NaOCl and H2O2 treated water. Adsorption capacity and adsorption intensity of A. hydrophila cells on polythene in NaOCl treated water were greater than that obtained in water disinfected with H2O2. Adhesion kinetics of A. hydrophila cells oscillated between 0.001 and 0.930 adhered cell.cm-2.h-1. Adsorption kinetics seem resulted from interactions between bacterial cells and substrates, and depended both on the fragment type and bacterial species. The values of A. hydrophila surface hydrophobicity fluctuated between 65.11 and 92.74% in NaOCl disinfected water and between 63.38 and 89.41% in H2O2 treated water. The mean values of contact angle ranged from 83.1±0.6 to 85.8±0.8°.   Adhesion of A. hydrophila on polythene is mediated amongst others by cell growth phases, cell surface hydrophobicity, cell kinetic adhesion, adsorption capacity and adsorption intensity

Elastic properties of grafted microtubules

We use single-particle tracking to study the elastic properties of single microtubules grafted to a substrate. Thermal fluctuations of the free microtubule's end are recorded, in order to measure position distribution functions from which we calculate the persistence length of microtubules with contour lengths between 2.6 and 48 micrometers. We find the persistence length to vary by more than a factor of 20 over the total range of contour lengths. Our results support the hypothesis that shearing between protofilaments contributes significantly to the mechanics of microtubules.Comment: 9 pages, 3 figure