605 research outputs found
Angular Motion of the Spin Axis of the Tiros 1 Meteorological Satellite due to Magnetic and Gravitational Torques
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Partial Nephrectomy in a Patient with a Left Ventricular Assist Device
Left ventricular assist device (LVAD) use has increased as a bridge to heart transplant as well as destination therapy in patients with severe heart failure. Presence of LVAD is not a contraindication to noncardiac surgery but does present special challenges to the surgical, anesthesia, and cardiac teams. We present the case of a 40-year-old woman with idiopathic cardiomyopathy necessitating LVAD who underwent left partial nephrectomy for a renal mass. She had undergone three nondiagnostic percutaneous image-guided biopsies. Left partial nephrectomy was performed. Perioperative care was without incident due to careful oversight by a multidisciplinary team. Pathology revealed high-grade clear cell renal cell carcinoma (RCC) with negative margins. Polytetrafluoroethylene (PTFE) bolsters were misidentified six months postoperatively on computed tomography (CT) at an outside institution as a retained laparotomy sponge. This is, to our knowledge, the first report of a partial nephrectomy performed in a patient with LVAD
Experimental benchmarking of Monte Carlo simulations for radiotherapy dosimetry using monochromatic X-ray beams in the presence of metal-based compounds
The local dose deposition obtained in X-ray radiotherapy can be increased by the presence of metal-based compounds in the irradiated tissues. This finding is strongly enhanced if the radiation energy is chosen in the kiloelectronvolt energy range, due to the proximity to the absorption edge. In this study, we present a MC application developed with the toolkit Geant4 to investigate the dosimetric distribution of a uniform monochromatic X-ray beam, and benchmark it against experimental measurements. Two validation studies were performed, using a commercial PTW RW3 water-equivalent slab phantom for radiotherapy, and a custom-made PMMA phantom conceived to assess the influence of high atomic number compounds on the dose profile, such as iodine and gadolinium at different concentrations. An agreement within 9% among simulations and experimental data was found for the monochromatic energies considered, which were in the range of 30–140 keV; the agreement was better than 5% for depths <60 mm. A dose enhancement was observed in the calculations, corresponding to the regions containing the contrast agents. Dose enhancement factors (DEFs) were calculated, and the highest values were found for energies higher than the corresponding K-edges of iodine and gadolinium. The in-silico results are in line with the empirical findings, which suggest that Geant4 can be satisfactorily used as a tool for the calculation of the percentage depth dose (PDD) at the energies considered in this study in the presence of contrast agents
A Review of the NASA MLAS Flight Demonstration
The NASA Engineering and Safety Center (NESC) has tested the Max Launch Abort System (MLAS) as a risk-mitigation design should problems arise with the baseline Orion spacecraft launch abort design. The Max in MLAS is not Maximum, but rather dedicated to Max Faget, the renowned NASA Spacecraft designer. In July 2009, the mission was flown, with great success, from the NASA Wallops Flight Facility. The MLAS flight test vehicle prototype consists of a boost skirt, coast skirt, and the MLAS fairing itself, which houses an Orion Command Module (CM) boilerplate. The objective of the MLAS flight test is to reorient the fairing with the CM, weighing approximately 29,000 lbs and traveling 290 fps, 180 degrees to an orientation suitable for the release of the CM during a pad abort or low altitude abort. The boost and coast skirts provide the necessary thrust and stability to establish the flight test conditions and are released prior to the reorientation of the fairing. A secondary test objective after successful release of the CM from the fairing is to demonstrate the removal of the CM forward bay cover (FBC) with the CM drogue parachutes, and subsequent deployment of the CM main parachutes attached to the FBC. Although multiple parachute deployments are used in the MLAS flight test vehicle to complete its objective, there are only two parachute types employed in the flight test. Five of the nine parachutes used for MLAS are 27.6 ft DO ribbon parachutes already proven as a spin/stall parachute for military aircraft, and the remaining four are G-12 cargo parachutes modified for increased strength and reefing. This paper presents an overview of the 27.6 ft DO ribbon parachute system employed on the MLAS flight test vehicle for coast skirt separation, fairing reorientation, and as CM drogue parachutes. Discussion will include: the process used to select this design; descriptions of all components of the parachute system; the minor modifications necessary to adapt the parachute to the MLAS program; the techniques used to analyze the parachute for the multiple roles it performs including discussions of how the evolution of the program affected parachute usage and analysis; a summary of the results of the highly successful flight test, including video of the flight test; and an overview of the subsequent post-test analysis
Letter on “Protection by exclusion? The (lack of) inclusion of adults who lack capacity to consent to research in clinical trials in the UK”
Effectiveness of adalimumab in treating patients with active psoriatic arthritis and predictors of good clinical responses for arthritis, skin and nail lesions
International audienceObjectives: To evaluate the effectiveness of adalimumab in patients with psoriatic arthritis (PsA) and identify predictors of good clinical response for joint and skin lesions. Methods: Patients received adalimumab 40 mg every other week in addition to standard therapy in this prospective, 12-week, open-label, uncontrolled study. Four definitions of good clinical response were used: >= 50% improvement in American College of Rheumatology response criteria (ACR50), good response according to European League Against Rheumatism (EULAR) guidelines, a >= 3-grade improvement in Physician Global Assessment of psoriasis (PGA) and a >= 50% improvement in the Nail Psoriasis Severity Index (NAPSI). Response predictors were determined by logistic regression with backward elimination (selection level was 5%). Results: Of 442 patients, 94% completed 12 weeks of treatment. At week 12, 74%, 51% and 32% of the patients had achieved ACR20, 50 and 70, respectively; 87% and 61% experienced moderate and good responses according to EULAR criteria, respectively. The percentage of patients with PGA results of "clear/almost clear'' increased from 34% (baseline) to 68%. The mean NAPSI score was reduced by 44%. No new safety signals were detected. A lower Health Assessment Questionnaire Disability Index (HAQ-DI) score, greater pain assessment, male sex and absence of systemic glucocorticoid therapy were strongly associated with achievement of ACR50 and good response according to EULAR criteria. In addition, greater C-reactive protein concentration and polyarthritis predicted ACR50, and non-involvement of large joints predicted a good response according to EULAR criteria. Conclusions: Adalimumab was effective in patients with PsA. Lower impairment of physical function, greater pain, male sex and no systemic treatment with glucocorticoids were factors that increased the chance of achieving a good clinical response
The echidna Tachyglossus aculeatus combines REM and non-REM aspects in a single sleep state: implications for the evolution of sleep
Placental and marsupial mammals exist in three states of consciousness: waking, non-REM sleep, and REM sleep. We now report that the echidna Tachyglossus aculeatus, a representative of the earliest branch of mammalian evolution (the monotremes), does not have the pattern of neuronal activity of either of the sleep states seen in nonmonotreme mammals. Echidna sleep was characterized by increased brainstem unit discharge variability, as in REM sleep. However, the discharge rate decreased and the EEG was synchronized, as in non-REM sleep. Our results suggest that REM and non-REM sleep evolved as a differentiation of a single, phylogenetically older sleep state. We hypothesize that the physiological changes that occur during postnatal sleep development parallel certain aspects of the changes that have occurred during the evolution of sleep-waking states in mammals
OPTIma:a tracking solution for proton computed tomography in high proton flux environments
Currently there is a large discrepancy between the currents that are used for treatments in proton beam therapy facilities and the ultra low beam currents required for many proton CT imaging systems. Here we provide details of the OPTIma silicon strip based tracking system, which has been designed for performing proton CT imaging in conditions closer to the high proton flux environments of modern spot scanning treatment facilities. Details on the physical design, sensor testing, modelling, and track reconstruction are provided along with Monte-Carlo simulation studies of the expected performance for proton beam currents of up to 50 pA at the nozzle when using a σ = ∼10 mm spot scanning cyclotron system. Using a detailed simulation of the proposed OPTIma system, a discrepancy of less than 1% on the Relative Stopping Power is found for various tissues when embedded within a 150 mm diameter Perspex sphere. It is found that by accepting up to 7 protons per bunch it is possible to operate at cyclotron beam currents up to 5 times higher than would be possible with a single proton based readout, significantly reducing the total beam time required to produce an image, while also reducing the discrepancy between the beam currents required for treatment and those used for proton CT
Essential protein P116 extracts cholesterol and other indispensable lipids for Mycoplasmas
Mycoplasma pneumoniae, responsible for approximately 30% of community-acquired human pneumonia, needs to extract lipids from the host environment for survival and proliferation. Here, we report a comprehensive structural and functional analysis of the previously uncharacterized protein P116 (MPN_213). Single-particle cryo-electron microscopy of P116 reveals a homodimer presenting a previously unseen fold, forming a huge hydrophobic cavity, which is fully accessible to solvent. Lipidomics analysis shows that P116 specifically extracts lipids such as phosphatidylcholine, sphingomyelin and cholesterol. Structures of different conformational states reveal the mechanism by which lipids are extracted. This finding immediately suggests a way to control Mycoplasma infection by interfering with lipid uptake.We thank L. Company and I. Fernández-Vidal for their support during MALS and mass spectroscopy measurements, A. Iborra (Servei de Cultius Cellulars, Anticossos Citometria, UAB) for his assistance with immunizing mice, D. Santos for his assistance in the radioactivity experiment and R. Pérez-Luque and D. Aparicio for their constant support and discussions. J. P. was funded by grants BIO2017-84166-R and PID2021-125632OB-C22 from the ministerio de Ciencia, Innovación y Universidades (MICINN, Spain). I. F. was funded by MICINN-Spain grant PID2021-125632OB-C21. A. S. F. was supported by the Deutsche Forschungsgemeinschaft (FR 1653/14-1 for MS and, FR 1653/6-3 for LS) and the Research Training Group iMOL (GRK 2566/1 for SM)
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