1,010 research outputs found

    Optical measurement of propeller blade deflections in a spin facility

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    A nonintrusive optical system for measuring propeller blade deflections has been used in the NASA Lewis dynamic spin facility. Deflection of points at the leading and trailing edges of a blade section can be obtained with a narrow light beam from a low power helium-neon laser. A system used to measure these deflections at three spanwise locations is described. Modifications required to operate the lasers in a near-vacuum environment are also discussed

    Scanning Hall Probe Microscopy (SHPM) using quartz crystal AFM feedback

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    Radiological study on mandibular ramus asymmetry in young population

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    Background: The aim of this study was to estimate the prevalence of ramus asymmetries related to age and gender in a young population and the influence of growth spurt on ramus asymmetry. Materials and methods: The study consisted of 776 panoramic radiographs of individuals aged 9 to 21 years (335 males and 441 females). Individuals were divided into two groups with respect of linear growth spurt as age 12 in females and age 14 in males. The first group consisted of females aged between 9 and 11 and males between 9 and 13. The second group consisted of females aged between 12 and 21 and males between 14 and 21. Bilateral ramus heights on each radiograph were measured. A panoramic software programme was used to measure the ramus heights. Quantitative data was tested by Student’s t test. Qualitative data was tested by χ2 test. The intraclass correlation coefficient was calculated for the magnitude error of the measurement. Results: The mean of ramus asymmetry was found to be 2.90% ± 2.58%. Significant differences between the right and left ramus height ratios were observed (p < 0.01). There was a high prevalence (10.8%) of ramus asymmetry, which did not correlate with the age and gender of the patients. Conclusions: This study revealed a high prevalence of ramus asymmetry in 9–21- -year-old population. Within the limitations of this study, it can be concluded that ramus asymmetry should be carefully evaluated in all ages for the potential relation with temporomandibular dysfunctions and also for orthodontic anomalies

    Single dose of intra-muscular platelet rich plasma reverses the increase in plasma iron levels in exercise-induced muscle damage: A pilot study

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    Background Platelet rich plasma (PRP) therapy is widely used in enhancing the recovery of skeletal muscle from injury. However, the impact of intramuscular delivery of PRP on hematologic and biochemical responses has not been fully elucidated in exercise-induced muscle damage. The purpose of this investigation the effects of intramuscular delivery of PRP on hematologic and biochemical responses and recovery strategy muscle damage induced by high intensity muscle exercise (exercise-induced muscle damage, EIMD). Methods Moderately active male volunteers participated in this study and were assigned to a control group (control, n = 6) and PRP administration group (PRP, n = 6). The subjects performed exercise with a load of 80% one repetition maximum (1RM) maximal voluntary contraction of the elbow flexors until point of exhaustion of the non-dominant arm was reached. The arms were treated with saline or autologous PRP post-24 h EIMD. Venous blood samples were obtained in the morning to establish a baseline value and 1–4 days post-exercise and were analyzed for serum ferritin, iron, iron binding capacity (IBC), creatinine kinase (CK), lactate dehydrogenase (LDH), aspartate aminotransferase (AST), and alanine aminotransferase (ALT). Results The baseline levels of plasma iron, ferritin, IBC, CK, LDH, AST, and ALT were similar in both the control and PRP groups. However, 24-h following exercise a significant increase in these parameters was observed in both groups between 1 and 4 days during the recovery period. Interestingly, PRP administration decreased plasma iron levels compared to the control on the second day post-exercise. Plasma IBC increased in PRP group from Days 2 to 4 post-exercise compared to the control group whilst PRP administration had no effect on plasma ferritin, CK, AST, ALT, or LDH. Conclusion Acute exhaustive exercise increased muscle damage markers, including plasma iron, IBC, and ferritin levels, indicating muscle damage induced by exercise. PRP administration improves inflammation by reversing the increase in the iron levels post-exercise without displaying any myotoxicity and may have a role to play in the recovery of exercise-induced muscle damage

    Immunodepletion in xenotransplantation

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    Xenograft transplantation is perhaps the most immunologically difficult problem in transplantation today. An overwhelming hyperacute rejection reaction (HAR) occurs within minutes of organ implantation. Preformed antibodies are thought to initiate this process. We used a pig-to-dog renal xenograft transplant model and investigated methods of decreasing the severity of hyperacute rejection. Female pigs weighing 15-20 kg were used as donors. Recipients were mongrel dogs weighing 15-25 kg. Experimental dogs were all given a number of treatments of IgG depletion using an antibody removal system (Dupont-Excorim). This machine immunoadsorbs plasma against a column containing immobilized staphylococcal protein A, which is known to bind the IgG Fc receptor. An 84% reduction in the IgG levels and a 71% reduction in IgM levels was achieved. Postoperative assessment was made of urine output, time to onset of HAR, and histopathological examination of the rejected kidneys. Although cross-matches between donor lymphocytes and recipient sera remained strongly positive in the treated dogs, there was a two- to fourfold reduction in the titers. The time to onset of HAR was prolonged in the experimental group, and the urine output was increased slightly. The histopathologic changes in the experimental group generally showed signs of HAR, but of less intensity than in the nonimmunodepleted control group. © 1990 Informa UK Ltd All rights reserved: reproduction in whole or part not permitted

    50 nm Hall Sensors for Room Temperature Scanning Hall Probe Microscopy

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    Bismuth nano-Hall sensors with dimensions ∼50nm × 50 nm were fabricated using a combination of optical lithography and focused ion beam milling. The Hall coefficient, series resistance and optimum magnetic field sensitivity of the sensors were 4 × 10-4 Ω/G, 9.1kΩ and 0.8G/√Hz, respectively. A 50nm nano-Bi Hall sensor was installed into a room temperature scanning Hall probe microscope and successfully used for directly imaging ferromagnetic domains of low coercivity garnet thin films

    Gastric bypass in modern bariatric surgery

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    The Roux-en-Y Gastric bypass surgery has long been considered as the «gold standard» method for the surgical treatment of obesity and its complications. But at present, this position is disputed by supporters of one-anastomotic gastric bypass and sleeve gastrectomy. The decrease in the share of gastric bypass in the structure of bariatric operations is explained by technical complexity, surgical and malabsorption complications. This review reflects the main role of gastric bypass as a bariatric surgery in the treatment of obesity and metabolic syndrome, and discloses various options for the technical implementation of gastric bypass surgery according to Roux-en-Y and alternative one-anastomotic gastric bypass surgery. The advantages and disadvantages of the stapler-use and stapleless method for performing bariatric operations are shown. In our opinion, one of the promising alternative concepts for the surgical treatment of obesity is stapleless one-anastomotic direction in gastric bypass surgery, but the known stapleless methods are imperfect and unsafe. Thus, based on the presented literature review, we can conclude that the imperfection of not only the stapler gastric bypass methods, but also the stapleless method. Therefore, a further research is needed for alternative surgical methods that would reduce the likelihood of surgical complications, reduce the cost of bariatric surgery and increase the accessibility of surgical treatment of obesity for the population

    The treatment of the metabolic syndrome with stapleless one-anastomotic gastric bypass: a randomized clinical trial compared to stapler method

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    BACKGROUND: The authors have developed an original method of laparoscopic gastric bypass significantly reducing financial costs when conducting this surgical treatment of obesity. In the presented article for the first time describes the evaluation of the effectiveness of the proposed to introduce a new type of staplerless gastric bypass compared to the standard stapler method. AIMS: to evaluate the effectiveness of the author’s method of laparoscopic gastric bypass for the treatment of metabolic syndrome with obesity. MATERIALS AND METHODS: This prospective, randomized controlled trial presents the results of surgical treatment of 80 patients with metabolic syndrome. Patients were randomized into two groups of 40 people. In the first group, the author’s method of laparoscopic mini-gastric bypass with a band-separated pouch was implemented, and in the second group, the standard laparoscopic mini-gastric bypass with a standard (stapler-separated) gastric pouch was used. Procedures were performed in the period from 2015 to 2016 with an average follow up period of 3 years. The postoperative change of weight loss and the changes of the main manifestations of the metabolic syndrome, as well as the change in the cardiovascular risk index in the comparison groups were assessed. RESULTS: In both groups there were no significant differences by sex and age. In the first group there were 39 women and 1 man, and in the second group 36 women and 4 men aged 36.75±8.6 years and 40.47±11.0 years, respectively (p=0.097). Three years after surgery, all 80 patients were examined using analysis of variance. At the same time, it was revealed that the change in body mass index after operations, which was 14.02±5.05 kg/m2 in the first group, and 12.38±5.7 kg/m2 (p=0.170) in the second group, was found equally good bariatric effect of two compared methods of gastric bypass. The main indicators of blood pressure, as well as laboratory data reflecting the state of carbohydrate and fat metabolism, statistically significantly decreased in both groups to normal values, which suggests a pronounced metabolic effect of both gastric bypass methods. It was established that cardiovascular risk in the first group decreased from 5.4±0.9 to 2.9±0.4 (p<0.001), and in the second group from 5.1±1.1 to 3.1±0.32 (p<0.001). CONCLUSIONS: The results of the use of various types of laparoscopic gastric bypass in the surgical treatment of metabolic syndrome after three years indicate a significant reduction in body weight, normalization of carbohydrate and fat metabolism. In a comparative aspect, the author’s and standard gastric bypass techniques equally positively affect the elimination of the main manifestations of the metabolic syndrome, but the proposed author’s method has insignificant advantages in terms of weight loss
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