111 research outputs found

    Study on Flow Characteristics of Oil Viscosity Pump for Refrigerant Compressors

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    Â Oil viscosity pumps are typically used for reciprocating compressors in household refrigerators to lubricate the compression mechanism. The oil viscosity pump is a simple structure in which a spiral groove is on the shaft surface. The lubricating oil supplied by this pump has a large influence on the performance and reliability, but the oil viscosity pump is designed based on the experience. We investigated the flow characteristics of the oil viscosity pump from theoretical and experimental study. We performed the study based on the assumption that the oil flow inside spiral groove was steady with two-dimensional viscous flow. As a result, we found that the pressure-flow rate (P-Q) characteristics has a linear relationship when the length of the spiral grooves, the rotational speed of the shaft, and the depth of the spiral grooves are in the limited area

    Compressor with Turning-Paired Vane and Piston

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    With the aim of energy saving of room air conditioners, we are addressing higher efficiency of the rotary compressor that is used most in the world. We focused on a new rotary compressor equipped with a mechanism to restrict the rolling motion of the piston, and performed the dynamics analysis. The new rotary compressor has a small pillar at the tip of the vane and constitutes a turning pair of vane and piston, and it limits the rolling motion of the piston. By means of limiting the piston rotation, the heat transfer to the suction process from the compression chamber will be suppressed, and we can expect higher compression efficiency. Before examining the compression efficiency, we performed the dynamics analysis of this new rotary compressor and examined the forces and dynamic behavior of the components, and the mechanical efficiency of the compressor. Then we have following results. (1)We can clarify the contact point between the vane tip and piston in the turning pair by considering the equilibrium of forces and moments acting on the vane. (2)By reducing the diameter of the pillar at the vane tip, the vane tip friction loss is reduced, and the mechanical efficiency is improved. (3)The new rotary compressor has less vane tip friction loss and on the other hand greater friction loss between the vane side and the cylinder in comparison to the rolling piston rotary compressors. As a result, both compressors have almost the same mechanical efficiency

    Engineering and characterization of a packaged high-T c superconducting terahertz source module

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    We present an effective engineering technique for compactly packaging high-T c superconducting continuous-wave terahertz source modules. A terahertz-emitting device, which consists of stacks of intrinsic Josephson junctions in single crystalline Bi2Sr2CaCu2O8+δ{}_{8+\delta }, bias electrodes, a collimating lens, and other components, is packaged into a single finger-sized assembly. The rigid and stable structure used for the packaging guarantees physical and chemical stability with good thermal contact, and provides reproducible characteristics with a high yield rate. The coherent terahertz waves can be emitted from the back side of the base crystal without significant screening. The intuitive results obtained from the numerical simulation are consistent with the observed thermal properties. The modules are easy to use, and thus intended for all users unfamiliar with superconducting electronic devices

    Cholecalciferol Supplementation Attenuates Bone Loss in Incident Kidney Transplant Recipients: A Prespecified Secondary Endpoint Analysis of a Randomized Controlled Trial

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    Vitamin D deficiency, persistent hyperparathyroidism, and bone loss are common after kidney transplantation (KTx). However, limited evidence exists regarding the effects of cholecalciferol supplementation on parathyroid hormone (PTH) and bone loss after KTx. In this prespecified secondary endpoint analysis of a randomized controlled trial, we evaluated changes in PTH, bone metabolic markers, and bone mineral density (BMD). At 1 month post-transplant, we randomized 193 patients to an 11-month intervention with cholecalciferol (4000 IU/d) or placebo. The median baseline 25-hydroxyvitamin D (25[OH]D) level was 10 ng/mL and 44% of participants had osteopenia or osteoporosis. At the end of the study, the median 25(OH)D level was increased to 40 ng/mL in the cholecalciferol group and substantially unchanged in the placebo group. Compared with placebo, cholecalciferol significantly reduced whole PTH concentrations (between-group difference of −15%; 95% confidence interval [CI] −25 to −3), with greater treatment effects in subgroups with lower 25(OH)D, lower serum calcium, or higher estimated glomerular filtration rate (pint < 0.05). The percent change in lumbar spine (LS) BMD from before KTx to 12 months post-transplant was −0.2% (95% CI −1.4 to 0.9) in the cholecalciferol group and −1.9% (95% CI −3.0 to −0.8) in the placebo group, with a significant between-group difference (1.7%; 95% CI 0.1 to 3.3). The beneficial effect of cholecalciferol on LS BMD was prominent in patients with low bone mass pint < 0.05). Changes in serum calcium, phosphate, bone metabolic markers, and BMD at the distal radius were not different between groups. In mediation analyses, change in whole PTH levels explained 39% of treatment effects on BMD change. In conclusion, 4000 IU/d cholecalciferol significantly reduced PTH levels and attenuated LS BMD loss after KTx. This regimen has the potential to eliminate vitamin D deficiency and provides beneficial effects on bone health even under glucocorticoid treatment. © 2021 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research (ASBMR).Tsujita M., Doi Y., Obi Y., et al. Cholecalciferol Supplementation Attenuates Bone Loss in Incident Kidney Transplant Recipients: A Prespecified Secondary Endpoint Analysis of a Randomized Controlled Trial. Journal of Bone and Mineral Research 37, 303 (2022); https://doi.org/10.1002/jbmr.4469

    1-year tolvaptan efficacy in ADPKD

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    Autosomal dominant polycystic kidney disease (ADPKD) develops into end-stage kidney disease by 65 years of age in an estimated 45%-70% of patients. Recent trials revealed that tolvaptan inhibits disease progression both in early-stage or late-stage ADPKD ; however, stratified analysis showed a difference of favorable factors correlated with tolvaptan efficacy between early-stage and late-stage ADPKD. Thus, we examined the efficacy of tolvaptan in ADPKD with a wide range of estimated glomerular filtration rates (eGFR). We enrolled 24 patients with eGFR 35.3 (28.0-65.5) ml / min / 1.73m2 and evaluated treatment effect as ΔΔeGFR (ml / min / 1.73m2 / year) or ΔΔtotal kidney volume (TKV) (% / year) that was calculated as post-treatment annual change - pre-treatment annual change. Pre ΔeGFR was significantly low in eGFR responders, defined as ΔΔeGFR > 0 ml / min / 1.73m2 / year. In eGFR responders, pre ΔeGFR, post ΔeGFR, eGFR, TKV, and proteinuria were significantly correlated with ΔΔeGFR. In TKV responders defined as ΔΔTKV > 5 % / year, we identified hypertension history, proteinuria, TKV, and post ΔTKV as significantly correlated factors with ΔΔTKV. In conclusion, pre ΔeGFR may be a predictive factor of therapeutic efficacy on kidney function. Tolvaptan may have greater efficacy in early-stage ADPKD with rapid GFR decline or with well-controlled blood pressure

    The effect of cholecalciferol supplementation on allograft function in incident kidney transplant recipients: A randomized controlled study

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    It is unknown whether cholecalciferol supplementation improves allograft outcomes in kidney transplant recipients (KTRs). We conducted a single-center randomized, double-blind, placebo-controlled trial of daily 4000 IU cholecalciferol supplementation in KTRs at 1-month posttransplant. The primary endpoint was the change in eGFR from baseline to 12-month posttransplant. Secondary endpoints included severity of interstitial fibrosis and tubular atrophy (IFTA) at 12-month posttransplant and changes in urinary biomarkers. Of 193 randomized patients, 180 participants completed the study. Changes in eGFR were 1.2 mL/min/1.73 m2 (95% CI; −0.7 to 3.1) in the cholecalciferol group and 1.8 mL/min/1.73 m2 (95% CI, −0.02 to 3.7) in the placebo group, with no significant between-group difference (−0.7 mL/min/1.73 m2 [95% CI; −3.3 to 2.0], p = 0.63). Subgroup analyses showed detrimental effects of cholecalciferol in patients with eGFR <45 mL/min/1.73 m2 (Pinteraction <0.05, between-group difference; −4.3 mL/min/1.73 m2 [95% CI; −7.3 to −1.3]). The degree of IFTA, changes in urine albumin-to-creatinine ratio, or adverse events including hypercalcemia and infections requiring hospitalization did not differ between groups. In conclusion, cholecalciferol supplementation did not affect eGFR change compared to placebo among incident KTRs. These findings do not support cholecalciferol supplementation for improving allograft function in incident KTRs. Clinical trial registry: This study was registered in the University Hospital Medical Information Network Clinical Trials Registry (UMIN-CTR) as UMIN000020597 (please refer to the links below). UMIN-CTR: https://upload.umin.ac.jp/cgi-open-bin/ctr_e/ctr_view.cgi?recptno=R000023776.Doi Y., Tsujita M., Hamano T., et al. The effect of cholecalciferol supplementation on allograft function in incident kidney transplant recipients: A randomized controlled study. American Journal of Transplantation 21, 3043 (2021); https://doi.org/10.1111/ajt.16530

    Comprehensive genomic profiling for patients with chemotherapy‐naïve advanced cancer

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    Comprehensive genomic profiling (CGP) testing by next-generation sequencing has been introduced into clinical practice as part of precision cancer medicine to select effective targeted therapies. However, whether CGP testing at the time of first-line chemotherapy could be clinically useful is not clear. We conducted this single-center, prospective, observational study to investigate the feasibility of CGP testing for chemotherapy-naïve patients with stage III/IV gastrointestinal cancer, rare cancer, and cancer of unknown primary, using the FoundationOne® companion diagnostic (F1CDx) assay. The primary outcome was the detection rate of at least one actionable/druggable cancer genomic alteration. Actionable/druggable cancer genomic alterations were determined by the F1CDx report. An institutional molecular tumor board determined the molecular-based recommended therapies. A total of 197 patients were enrolled from October 2018 to June 2019. CGP success rate was 76.6% (151 of 197 patients), and median turnaround time was 19 days (range: 10-329 days). Actionable and druggable cancer genomic alterations were reported in 145 (73.6%) and 124 (62.9%) patients, respectively. The highest detection rate of druggable genomic alterations in gastrointestinal cancers was 80% in colorectal cancer (48 of 60 patients). Molecular-based recommended therapies were determined in 46 patients (23.4%). CGP testing would be a useful tool for the identification of a potentially effective first-line chemotherapy

    The Far-Infrared Surveyor (FIS) for AKARI

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    The Far-Infrared Surveyor (FIS) is one of two focal plane instruments on the AKARI satellite. FIS has four photometric bands at 65, 90, 140, and 160 um, and uses two kinds of array detectors. The FIS arrays and optics are designed to sweep the sky with high spatial resolution and redundancy. The actual scan width is more than eight arcmin, and the pixel pitch is matches the diffraction limit of the telescope. Derived point spread functions (PSFs) from observations of asteroids are similar to the optical model. Significant excesses, however, are clearly seen around tails of the PSFs, whose contributions are about 30% of the total power. All FIS functions are operating well in orbit, and its performance meets the laboratory characterizations, except for the two longer wavelength bands, which are not performing as well as characterized. Furthermore, the FIS has a spectroscopic capability using a Fourier transform spectrometer (FTS). Because the FTS takes advantage of the optics and detectors of the photometer, it can simultaneously make a spectral map. This paper summarizes the in-flight technical and operational performance of the FIS.Comment: 23 pages, 10 figures, and 2 tables. Accepted for publication in the AKARI special issue of the Publications of the Astronomical Society of Japa

    Kcnab1 Is Expressed in Subplate Neurons With Unilateral Long-Range Inter-Areal Projections

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    Subplate (SP) neurons are among the earliest-born neurons in the cerebral cortex and heterogeneous in terms of gene expression. SP neurons consist mainly of projection neurons, which begin to extend their axons to specific target areas very early during development. However, the relationships between axon projection and gene expression patterns of the SP neurons, and their remnant layer 6b (L6b) neurons, are largely unknown. In this study, we analyzed the corticocortical projections of L6b/SP neurons in the mouse cortex and searched for a marker gene expressed in L6b/SP neurons that have ipsilateral inter-areal projections. Retrograde tracing experiments demonstrated that L6b/SP neurons in the primary somatosensory cortex (S1) projected to the primary motor cortex (M1) within the same cortical hemisphere at postnatal day (PD) 2 but did not show any callosal projection. This unilateral projection pattern persisted into adulthood. Our microarray analysis identified the gene encoding a β subunit of voltage-gated potassium channel (Kcnab1) as being expressed in L6b/SP. Double labeling with retrograde tracing and in situ hybridization demonstrated that Kcnab1 was expressed in the unilaterally-projecting neurons in L6b/SP. Embryonic expression was specifically detected in the SP as early as embryonic day (E) 14.5, shortly after the emergence of SP. Double immunostaining experiments revealed different degrees of co-expression of the protein product Kvβ1 with L6b/SP markers Ctgf (88%), Cplx3 (79%), and Nurr1 (58%), suggesting molecular subdivision of unilaterally-projecting L6b/SP neurons. In addition to expression in L6b/SP, scattered expression of Kcnab1 was observed during postnatal stages without layer specificity. Among splicing variants with three alternative first exons, the variant 1.1 explained all the cortical expression mentioned in this study. Together, our data suggest that L6b/SP neurons have corticocortical projections and Kcnab1 expression defines a subpopulation of L6b/SP neurons with a unilateral inter-areal projection
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