199 research outputs found
Interactions Between a Condensed Target and a Non-Equilibrium Plasma: Acid-Base Reactions at the Interface
A new approach of plasma processes of industrial use is presented, with emphasis on the chemical properties of the plasma gas. Reactions occurring at the gas/target interface are for the first time interpreted in terms of acid-base reactions and pertinent examples are given of laboratory experiments and of industrial treatments (e. g., etching, plasma polymerization or surface modification processes). Proton exchanges between the plasma phase and an aqueous target gives evidence of Bronsted acid-base phenomena. Illustrations of Lewis acid-base characters are provided by the role of biradicals (e.g., halogenocarbenes, nitrenc) which are the main reacting species in etching or in surface treatment processes
Investigation of hydrocarbon oil transformation by gliding arc discharge: comparison of batch and recirculated configurations
Оцінка якості життя у вікових першовагітних та вагітних з великим інтергенетичним інтервалом
Проведено изучение показателей качества жизни у 120 возрастных первобеременных и 240 беременных
с большим интергенетическим интервалом с использованием опросника SF-36 Health Status Survey,
разработанного The Health Institute, New England Medical Center, Boston, USA. Исследование показало, что
пациентки обеих групп имеют низкие показатели качества жизни. При сравнении большинство изучаемых
параметров оценки качества жизни в обследованных группах не отличались, однако у пациенток с большим
интергенетическим интервалом – достоверно выше оценка социальной роли и энергетичности.
Оценка качества жизни у возрастных первобеременных и беременных с большим интергенетическим
интервалом является важным сегментом наблюдения во время беременности, который оценивает
перспективы развития беременности в психологическом, физическом и социальном аспектах.A study of the life quality of 120 over-age primigravidas and of 240 women with a large intergenetic interval
has been carried out using the questionnaire SF-36 Health Status Survey developed by The Health Institute, New
England Medical Center, Boston, USA. This research has shown that the patients in the both groups have a low
quality of life. The major part of the life quality parameters were the same in the both groups, however, in patients
with a large interval between births the values of the social role and the energy level were significantly higher.
The life quality of over-age primigravidas and pregnant women with a large interval between successive
births is an important sector of observation during pregnancy, which allows assessing the prospects of pregnancy
in the psychological, physical, and social aspects
A Fixed-Wing Biplane MAV for Low Speed Missions
Practical MAVs missions, such as outdoor urban environment recognitions, simultaneously require a capability of both dashing to escape enemy fire and slowly loitering over a target in order to capture and transmit clear images to a ground station. Since an MAV intrinsically offers better payload and endurance capabilities than a rotorcraft of an equal size, fixed-wing MAVs can be considered as promising platforms to start with. The objective of this study is to investigate the possibility of developing a fixed-wing MAV which can both perform rapid translations and low-speed flights through urban canyons. Alow-speed wind tunnel testing is conducted to compare several powered configurations including monoplane, biplane and tandem wing combinations. The testing also focuses on wing-propeller interactions. Results indicate that a positive stagger biplane configuration powered by counter-rotating propellers placed in pusher position provides the best trade-off between a high-speed performance and a low-speed capability with a limited electric consumption. Consequently, a 30 cm span MAV biplane prototype, named TYTO-30, has been designed and built. TYTO-30 is equipped with a 110g-payload which includes a video camera, navigation and autopilot system and has been flight tested successfully
Thermal Stability of an Mg‐Nd Alloy Processed by High‐Pressure Torsion
The evolution of microstructure, texture and mechanical properties of an Mg‐1.43Nd (wt.%) alloy are investigated after processing by high‐pressure torsion at room temperature through 5 turns and isochronal annealing for 1 h at 150, 250, 350 and 450 °C using Electron BackScatter Diffraction and Vickers microhardness. The alloy exhibits a good thermal stability up to an annealing at 250 °C, with mean grain size of ≈0.65 μm. The microhardness shows an initial hardening after annealing at 150 °C and then a subsequent softening. The deformation texture, a basal texture shifted 60° away from the shear direction (SD), is retained during annealing up to 250 °C. By contrast, a basal texture with symmetrical splitting towards SD is developed after annealing at 350 °C. The precipitation sequence and their pinning effect are responsible for the age‐hardening, stabilization of grain size and the texture modification. The kinetics of grain growth in the Mg‐1.43Nd alloy follows two stages depending on the temperature annealing range, with an activation energy of ≈26 kJ/mol in the low temperature range of 150–250 °C and ~147 kJ/mol in the high temperature range of 250–450 °C
The Strata-l Experiment on Microgravity Regolith Segregation
The Strata-1 experiment studies the segregation of small-body regolith through long-duration exposure of simulant materials to the microgravity environment on the International Space Station (ISS). Many asteroids feature low bulk densities, which implies high values of porosity and a mechanical structure composed of loosely bound particles, (i.e. the "rubble pile" model), a prime example of a granular medium. Even the higher-density, mechanically coherent asteroids feature a significant surface layer of loose regolith. These bodies will evolve in response to very small perturbations such as micrometeoroid impacts, planetary flybys, and the YORP effect. A detailed understanding of asteroid mechanical evolution is needed in order to predict the surface characteristics of as-of-yet unvisited bodies, to understand the larger context of samples from sample return missions, and to mitigate risks for both manned and unmanned missions to asteroidal bodies. Due to observation of rocky regions on asteorids such as Eros and Itokawa, it has been hypothesized that grain size distribution with depth on an asteroid may be inhomogeneous: specifically, that large boulders have been mobilized to the surface. In terrestrial environments, this size-dependent sorting to the surface of the sample is called the Brazil Nut Effect. The microgravity and acceleration environment on the ISS is similar that of a small asteroid. Thus, Strata-1 investigates size segregation of regolith in an environment analogous to that of small bodies. Strata-1 consists of four regolith simulants in evacuated tubes, as shown in Figure 1 (Top and Middle). The simulants are (1) a crushed and sieved ordinary chondrite meteorite to simulate an asteroidal surface, (2) a carbonaceous chondrite simulant with a mixture of fine and course particles, and two simplified silicate glass simulants; (3) one with angular and (4) another with spherical particles. These materials were chosen to span a range of granular complexity. The materials were sorted into three size species pre-launch, and maintained during launch and return by a device called the Entrapulator. The hypothesis under test is that the particles that constitute a granular medium in a micro-gravity environment, subjected to a known vibration environemnt, will segregate in accordance to modeled predictions. Strata-1 is currently operating on ISS, with cameras capturing images of simulant motion throughout the one year mission. Vibration data is recorded and downlinked, and the simulants will be analyzed after return to Earth
Clinical and Immunopathological Features of Moyamoya Disease
Background: Moyamoya disease (MMD) is a cerebrovascular disease characterized by progressive stenosis or occlusion of the terminal portion of internal carotid arteries and the formation of a vascular network at the base of the brain. The pathogenesis of MMD is still unclear. Methodology/Principal Findings: We retrospectively analyzed clinical data for 65 consecutive patients with MMD in our institutions and evaluated the histopathological and immunohistochemical findings of intracranial vessels from 3 patients. The onset age distribution was found to have 1 peak at 40–49 year-old age group, no significant difference was observed in the female-to-male ratio (F/M = 1.2). Intracranial hemorrhage was the predominant disease type (75%). Positive family history was observed in 4.6 % of patients. Histopathological findings were a narrowed lumen due to intimal fibrous thickening without significant inflammatory cell infiltration, and the internal elastic lamina was markedly tortuous and stratified. All 3 autopsy cases showed vacuolar degeneration in the cerebrovascular smooth muscle cells. Immunohistochemical study showed the migration of smooth muscle cells in the thickened intima, and aberrant expression of IgG and S100A4 protein in vascular smooth muscle cells. The Complement C3 immunoreactivity was negative. Conclusion/Significance: This study indicated that aberrant expression of IgG and S100A4 protein in intracranial vascular wall of MMD patients, which suggested that immune-related factors may be involved in the functional and morphologica
Combined use of expression and CGH arrays pinpoints novel candidate genes in Ewing sarcoma family of tumors
<p>Abstract</p> <p>Background</p> <p>Ewing sarcoma family of tumors (ESFT), characterized by t(11;22)(q24;q12), is one of the most common tumors of bone in children and young adults. In addition to <it>EWS/FLI1 </it>gene fusion, copy number changes are known to be significant for the underlying neoplastic development of ESFT and for patient outcome. Our genome-wide high-resolution analysis aspired to pinpoint genomic regions of highest interest and possible target genes in these areas.</p> <p>Methods</p> <p>Array comparative genomic hybridization (CGH) and expression arrays were used to screen for copy number alterations and expression changes in ESFT patient samples. A total of 31 ESFT samples were analyzed by aCGH and in 16 patients DNA and RNA level data, created by expression arrays, was integrated. Time of the follow-up of these patients was 5–192 months. Clinical outcome was statistically evaluated by Kaplan-Meier/Logrank methods and RT-PCR was applied on 42 patient samples to study the gene of the highest interest.</p> <p>Results</p> <p>Copy number changes were detected in 87% of the cases. The most recurrent copy number changes were gains at 1q, 2, 8, and 12, and losses at 9p and 16q. Cumulative event free survival (ESFT) and overall survival (OS) were significantly better (P < 0.05) for primary tumors with three or less copy number changes than for tumors with higher number of copy number aberrations. In three samples copy number imbalances were detected in chromosomes 11 and 22 affecting the <it>FLI1 </it>and <it>EWSR1 </it>loci, suggesting that an unbalanced t(11;22) and subsequent duplication of the derivative chromosome harboring fusion gene is a common event in ESFT. Further, amplifications on chromosomes 20 and 22 seen in one patient sample suggest a novel translocation type between <it>EWSR1 </it>and an unidentified fusion partner at 20q. In total 20 novel ESFT associated putative oncogenes and tumor suppressor genes were found in the integration analysis of array CGH and expression data. Quantitative RT-PCR to study the expression levels of the most interesting gene, <it>HDGF</it>, confirmed that its expression was higher than in control samples. However, no association between <it>HDGF </it>expression and patient survival was observed.</p> <p>Conclusion</p> <p>We conclude that array CGH and integration analysis proved to be effective methods to identify chromosome regions and novel target genes involved in the tumorigenesis of ESFT.</p
Controversies in the management of advanced prostate cancer
For advanced prostate cancer, the main hormone treatment against which other treatments are assessed is surgical castration. It is simple, safe and effective, however it is not acceptable to all patients. Medical castration by means of luteinizing hormone-releasing hormone (LH-RH) analogues such as goserelin acetate provides an alternative to surgical castration. Diethylstilboestrol, previously the only non-surgical alternative to orchidectomy, is no longer routinely used. Castration reduces serum testosterone by around 90%, but does not affect androgen biosynthesis in the adrenal glands. Addition of an anti-androgen to medical or surgical castration blocks the effect of remaining testosterone on prostate cells and is termed combined androgen blockade (CAB). CAB has now been compared with castration alone (medical and surgical) in numerous clinical trials. Some trials show advantage of CAB over castration, whereas others report no significant difference. The author favours the view that CAB has an advantage over castration. No study has reported that CAB is less effective than castration. Of the anti-androgens which are available for use in CAB, bicalutamide may be associated with a lower incidence of side-effects compared with the other non-steroidal anti-androgens and, in common with nilutamide, has the advantage of once-daily dosing. Only one study has compared anti-androgens within CAB: bicalutamide plus LH-RH analogue and flutamide plus LH-RH analogue. At 160-week follow-up, the groups were equivalent in terms of survival and time to progression. However, bicalutamide caused significantly less diarrhoea than flutamide. Withdrawal and intermittent therapy with anti-androgens extend the range of treatment options. © 1999 Cancer Research Campaig
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