319 research outputs found
Measurement of the branching fraction for the decay neutral kaon(long) going to pion-antipion-positron-electron in the high M(pi-pi) invariant mass region
A measurement of the branching fraction for the rare decay K0L → pi+pi-e +e- was performed using data collected from experiment E871 which ran at the AGS of Brookhaven National Laboratory. Analysis of the data revealed 27.7 +/- 7.4 signal events in the signal region, 0.4905 GeV \u3c Mpipiee \u3c 0.505 GeV together with 13.3 +/- 3.7 background events. The branching fractions of ( 8.5+/-2.3stat +/-1.0sys ) x 10-6 using the phenomenological model acceptance and ( 2.3+/-0.6stat +/-0.3sys ) x 10-6 using the chiral perturbation model represent the first measurements for K0L → pi+pi-e +e- in the dipion invariant mass region 0.475 GeV \u3c Mpipi \u3c 0.497 GeV. These results support the prediction of chiral perturbation theory rather than that of the phenomenological model
Mechanical design and analysis of implantable components for a retinal prosthesis
Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 1999.Includes bibliographical references (p. 89-91).The success of a retinal prosthesis in restoring vision to blind patients will be dependent on its long term viability when implanted in the eye. This thesis addresses mechanical aspects relating to the biocompatibility of the device and its ability to survive in a saline environment. Chronic testing of a working prosthesis requires hermetic encapsulation of all implanted electronics; any direct contact with the fluid in the eye will damage the circuitry and render the device ineffectual. A metal housing, which has provided effective protection of other prostheses, would interfere with light transmission from the external source and is therefore impractical. Encapsulation of the electronics in transparent polymers is a potential alternative. Our current prosthesis design requires both a polyimide electrode array and a return wire to penetrate the protective capsule. Therefore, a technique for evaluating the hermetic encapsulation of these components was designed and tested. Simple, expendable models of the prosthesis were developed and used to test silicone as an encapsulant. In a 60 day soak test, all prosthesis models failed within three days, while completely encapsulated control models exhibited no current leakage. For the silicone application methods and implant materials currently being used, silicone is not an effective encapsulant. The majority of the implanted electronics, including a photodiode array, will be supported in the front of the eye by an intraocular support structure. Early designs of this structure were based on the structure of commercially available intraocular lenses commonly used in cataract surgeries. Using stereolithography, a rapid prototyping technique, this structure was redesigned based on mechanical and surgical criteria. The existing haptic system was modified to improve stability, and arrangement of the photodiode array on the structure was optimized. In addition, the structure itself was simplified for fabrication from biocompatible materials. Stability of the entire structure relative to the eye and of the photodiode array relative to the structure was analyzed using finite element methods. The final design, when injection molded from silicone rubber, was tested surgically by implantation into animal eyes. The surgery was successful, and the basic design will be used in future tests.by Joshua D. Moss.S.M
Simple irrigation checkup for home sprinkler systems
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Hypohydration impairs endurance performance: a blinded study
The general scientific consensus is that starting exercise with hypohydration >2% body mass impairs endurance performance/capacity, but most previous studies might be confounded by a lack of subject blinding. This study examined
the effect of hypohydration in a single blind manner using combined oral and intragastric rehydration to manipulate hydration status. After familiarization,
seven active males (mean ±SD: age 25± 2 years, height 1.79±0.07, body mass 78.6±6.2, VO2peak 48 ±7 mL.kg.min -1) completed two randomized trials at 34°C. Trials involved an intermittent exercise preload (8x15 min exercise/5 min rest), followed by a 15-min all-out performance test on a cycle ergometer. During the preload, water was ingested orally every
10 min (0.2 mL.kg body mass -1). Additional water was infused into the stomach via a gastric feeding tube to replace sweat loss (EU) or induce hypohydration
of ~2.5% body mass (HYP). Blood samples were drawn and thirst sensation rated before, during, and after exercise. Body mass loss during the preload was greater (2.4 ±0.2% vs. 0.1± 0.1%; P < 0.001), while work completed during the performance test was lower (152± 24 kJ vs. 165 ±22 kJ; P < 0.05) during HYP. At the end of the preload, heart rate, RPE, serum osmolality, and thirst were greater and plasma volume lower during HYP (P < 0.05). These results provide novel data demonstrating that exercise performance in the heat is impaired by hypohydration, even when subjects are
blinded to the intervention
Identification of a Core Amino Acid Motif within the α Subunit of GABAARs that Promotes Inhibitory Synaptogenesis and Resilience to Seizures
The fidelity of inhibitory neurotransmission is dependent on the accumulation of γ-aminobutyric acid type A receptors (GABAARs) at the appropriate synaptic sites. Synaptic GABAARs are constructed from α(1-3), β(1-3), and γ2 subunits, and neurons can target these subtypes to specific synapses. Here, we identify a 15-amino acid inhibitory synapse targeting motif (ISTM) within the α2 subunit that promotes the association between GABAARs and the inhibitory scaffold proteins collybistin and gephyrin. Using mice in which the ISTM has been introduced into the α1 subunit (Gabra1-2 mice), we show that the ISTM is critical for axo-axonic synapse formation, the efficacy of GABAergic neurotransmission, and seizure sensitivity. The Gabra1-2 mutation rescues seizure-induced lethality in Gabra2-1 mice, which lack axo-axonic synapses due to the deletion of the ISTM from the α2 subunit. Taken together, our data demonstrate that the ISTM plays a critical role in promoting inhibitory synapse formation, both in the axonic and somatodendritic compartments
The impact of surgical site infection on hospitalisation, treatment costs, and health-related quality of life after vascular surgery
Surgical site infections (SSI) substantially increase costs for healthcare providers because of additional treatments and extended patient recovery. The objective of this study was to assess the cost and health‐related quality of life impact of SSI, from the perspective of a large teaching hospital in England. Data were available for 144 participants undergoing clean or clean‐contaminated vascular surgery. SSI development, length of hospital stay, readmission, and antibiotic use were recorded over a 30‐day period. Patient‐reported EQ‐5D scores were obtained at baseline, day 7 and day 30. Linear regressions were used to control for confounding variables. A mean SSI‐associated length of stay of 9.72 days resulted in an additional cost of £3776 per patient (including a mean antibiotic cost of £532). Adjusting for age, smoking status, and procedure type, SSI was associated with a 92% increase in length of stay (P < 0.001). The adjusted episode cost was £3040. SSI reduced patient utility between baseline and day 30 by 0.156 (P = 0.236). Readmission rates were higher with SSI (P = 0.017), and the rate to return to work within 90 days was lower. Therefore, strategies to reduce the risk of surgical site infection for high‐risk vascular patients should be investigated
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Long-Term Corticosteroid-Sparing Immunosuppression for Cardiac Sarcoidosis.
Background Long-term corticosteroid therapy is the standard of care for treatment of cardiac sarcoidosis (CS). The efficacy of long-term corticosteroid-sparing immunosuppression in CS is unknown. The goal of this study was to assess the efficacy of methotrexate with or without adalimumab for long-term disease suppression in CS, and to assess recurrence and adverse event rates after immunosuppression discontinuation. Methods and Results Retrospective chart review identified treatment-naive CS patients at a single academic medical center who received corticosteroid-sparing maintenance therapy. Demographics, cardiac uptake of 18-fluorodeoxyglucose, and adverse cardiac events were compared before and during treatment and between those with persistent or interrupted immunosuppression. Twenty-eight CS patients were followed for a mean 4.1 (SD 1.5) years. Twenty-five patients received 4 to 8 weeks of high-dose prednisone (>30 mg/day), followed by taper and maintenance therapy with methotrexate±low-dose prednisone (low-dose prednisone, <10 mg/day). Adalimumab was added in 19 patients with persistently active CS or in those with intolerance to methotrexate. Methotrexate±low-dose prednisone resulted in initial reduction (88%) or elimination (60%) of 18-fluorodeoxyglucose uptake, and patients receiving adalimumab-containing regimens experienced improved (84%) or resolved (63%) 18-fluorodeoxyglucose uptake. Radiologic relapse occurred in 8 of 9 patients after immunosuppression cessation, 4 patients on methotrexate-containing regimens, and in no patients on adalimumab-containing regimens. Conclusions Corticosteroid-sparing regimens containing methotrexate with or without adalimumab is an effective maintenance therapy in patients after an initial response is confirmed. Disease recurrence in patients on and off immunosuppression support need for ongoing radiologic surveillance regardless of immunosuppression regimen
Gay and Bisexual Men’s Willingness to Use a Self-Collected Anal Cancer Screening Test
We investigated gay and bisexual men’s willingness to self-administer an anal cancer screening test at home
A search for radio afterglows from gamma-ray bursts with the Australian Square Kilometre Array Pathfinder
We present a search for radio afterglows from long gamma-ray bursts using the
Australian Square Kilometre Array Pathfinder (ASKAP). Our search used the Rapid
ASKAP Continuum Survey, covering the entire celestial sphere south of
declination , and three epochs of the Variables and Slow Transients
Pilot Survey (Phase 1), covering square degrees per epoch. The
observations we used from these surveys spanned a nine-month period from 2019
April 21 to 2020 January 11. We crossmatched radio sources found in these
surveys with 779 well-localised (to ) long gamma-ray bursts
occurring after 2004 and determined whether the associations were more likely
afterglow- or host-related through the analysis of optical images. In our
search, we detected one radio afterglow candidate associated with GRB 171205A,
a local low-luminosity gamma-ray burst with a supernova counterpart SN 2017iuk,
in an ASKAP observation 511 days post-burst. We confirmed this detection with
further observations of the radio afterglow using the Australia Telescope
Compact Array at 859 days and 884 days post-burst. Combining this data with
archival data from early-time radio observations, we showed the evolution of
the radio spectral energy distribution alone could reveal clear signatures of a
wind-like circumburst medium for the burst. Finally, we derived semi-analytical
estimates for the microphysical shock parameters of the burst: electron
power-law index , normalised wind-density parameter ,
fractional energy in electrons , and fractional energy in
magnetic fields .Comment: 18 pages, 7 figures; accepted for publication in MNRA
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