988 resultados para 1055


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We present the novel synthesis of two sugar units that are central intermediates for the formation of members of the bicyclo-DNA and -RNA family. The synthesis starts from commercially available 1,2: 5,6-di-O-isopropylidene-alpha-D-glucofuranose. The key step involves the elaboration of a carbocyclic ring in a furanoside by rhodium(I)-catalyzed hydroacylation. Via this pathway, one of the sugar units is available in 8 steps and in an overall yield of 27%, while its deoxy derivative is obtained in 11 steps, which is 5 steps fewer than in our previous synthesis of this compound.

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Background: This investigation describes experimental tests of the biomechanical features of a new resorbable bone adhesive based on methacrylate-terminated oligolactides enhanced with osteoconductive β-tricalcium phosphate. Material and Methods: 51 New Zealand white rabbits were randomised to an adhesive group (n = 29) and a control group (n = 22). An extra-articular bone cylinder was taken from the proximal tibia, two stripes of adhesive were applied and the cylinders were replanted. After 10 and 21 days, 3 and 12 months tibial specimens were harvested and the cylinder pull-out test was performed with a servo-hydraulic machine. Additionally the pull-out force was evaluated with the bone-equivalent Ebazell® after 5, 10 and 360 minutes in 14 specimens each. Results: Average pull-out forces in the adhesive group were 28 N after 10 days (control: 57 N), 155 N after 21 days (216 N), 184 N after 3 months (197 N) and 205 N after 12 months (185 N). Investigations with Ebazell® showed almost identical pull-out forces after 5 min, 15 min and 360 min. Adhesive forces were as high as 125 N/cm2 of adhesive surface and more than 1200 N/g of adhesive mass. Conclusions: The adhesive investigated here has a very good primary adhesive power, compared to the literature data, achieved after only 5 minutes. Even in moist surroundings the adhesive capacity remains sufficient. The adhesive has to prove its resorptive properties in further investigations and in first line its medium-term and long-lasting biocompatibility. Furthermore, biomechanical features will have to be compared to those of conventional fixation techniques.

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In this study, facilitated anastomosis using an anastomotic device was compared to conventional hand-sewn (HS) vascular anastomosis in an animal model.

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Umbilical vein pulsations (UV-P) are due to various etiologies. The aim of the present study was to investigate the incidence and type of UV-P in monochorionic twins with twin-twin transfusion syndrome (TTTS).

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Noninvasive blood flow measurements based on Doppler ultrasound studies are the main clinical tool for studying the cardiovascular status in fetuses at risk for circulatory compromise. Usually, qualitative analysis of peripheral arteries and, in particular clinical situations such as severe growth restriction or volume overload, also of venous vessels close to the heart or of flow patterns in the heart are being used to gauge the level of compensation in a fetus. Quantitative assessment of the driving force of the fetal circulation, the cardiac output, however, remains an elusive goal in fetal medicine. This article reviews the methods for direct and indirect assessment of cardiac function and explains new clinical applications. Part 1 of this review describes the concept of cardiac function and cardiac output and the techniques that have been used to quantify output. Part 2 summarizes the use of arterial and venous Doppler studies in the fetus and gives a detailed description of indirect measures of cardiac function (like indices derived from the duration of segments of the cardiac cycle) with current examples of their application.

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Forward-looking ground penetrating radar shows promise for detection of improvised explosive devices in active war zones. Because of certain insurmountable physical limitations, post-processing algorithm development is the most popular research topic in this field. One such investigative avenue explores the worthiness of frequency analysis during data post-processing. Using the finite difference time domain numerical method, simulations are run to test both mine and clutter frequency response. Mines are found to respond strongest at low frequencies and cause periodic changes in ground penetrating radar frequency results. These results are called into question, however, when clutter, a phenomenon generally known to be random, is also found to cause periodic frequency effects. Possible causes, including simulation inaccuracy, are considered. Although the clutter models used are found to be inadequately random, specular reflections of differing periodicity are found to return from both the mine and the ground. The presence of these specular reflections offers a potential alternative method of determining a mine’s presence.

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Glioblastoma patients should be provided with a professional health care system that helps reduce their psychosocial burden. The aim of this study was to identify patients in need of psychosocial intervention. In addition, it was examined whether physicians' assessments adequately address the burden patients are under and their need for intervention. During their visit to one of two neurosurgery outpatient departments, n = 49 glioblastoma patients filled out the short version of the Hornheider questionnaire (HFK). Consulting physicians also rated their patients' burdens in a specially adapted version of the questionnaire (HFK-F). The results of the psychometric evaluation with both instruments were satisfactory. The majority of the patients (76 %) were identified as in need of psychosocial intervention. All of them were correctly categorized with the physicians' ratings. Physicians overestimated some aspects of the patients' burden, particularly in regard to their problems with relaxing and fear of living with the illness. The patients' ratings concerning the quality of the information physicians provided and their overall state of health only corresponded with the physicians' ratings in roughly half of the cases.

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Visual results in treating neovascular age-related macular degeneration (AMD) using intravitreal injected anti-VEGF (IVT) clearly depend on injection frequency. Regarding to the European approval Ranibizumab has to be used only in cases of recurrent visual loss after the loading phase. In contrast monthly treatment--as also provided in the ANCHOR and MARINA studies--is generally allowed in Switzerland. However, it is commonly tried to reduce the injection frequency because of the particular cost situation in all health systems and of cause also due to the necessary strict monitoring and reinjection regimes, which raise management problems with increasing patient numbers. In this article the special treatment regimes of our University Eye Hospital is presented, in which a reduced injection frequency basically leads to the same increased and stable visual results as in ANCHOR and MARINA; however, needing significantly more injections as generally provided in other countries of Europe. The main focus for achieving this in a large number of patients is placed on re-structuring our outpatient flow for IVT patients with particular emphasis on patient separation and standardisation of treatment steps leading to significantly reduced time consumption per patient. Measurements of timing and patient satisfaction before and after restructuring underline its importance in order to be able to treat more patients at a high quality even in the future. The exceptional importance of spectral domain OCT measurements as the most important criterium for indicating re-treatment is illustrated.

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Purpose: Gender-specific differences exist between male and female infertility patients' mental health, the meaning of infertility in their lives, and the coping strategies used. This systematic review examines whether gender-specific aspects are addressed in psychological intervention studies for infertility and whether infertile women and men benefit equally from such interventions. Methods: Databases were searched to identify relevant articles published between 1978 and 2007 (384 articles). The review included both controlled and uncontrolled psychological intervention studies examining results for infertile women and men separately. Outcome measures (depressive symptoms, anxiety, and mental distress) and gender-specific baseline characteristics (mental distress at pre-assessment, cause of infertility, and medical treatment) were collected. A total of twelve studies were finally included. Results: In 10 of 12 studies, women exhibited higher levels of mental distress than men. Gender-specific aspects were not addressed in the psychological interventions. Examining the efficacy of psychological interventions revealed that women exhibited stronger positive mental health effects in 2 of the 12 studies. Conclusion: Psychological distress before psychological treatment seems more pronounced in women than in men. Therefore psychological interventions for infertile couples should take gender-specific aspects into account. More research is needed to address the gender-specific aspects regarding psychological interventions for infertility.

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To evaluate the effectiveness and safety of covered stents for the management of iatrogenic arterial injury.