787 research outputs found

    Multilayers of InGaAs Nanostructures Grown on GaAs(210) Substrates

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    Multilayers of InGaAs nanostructures are grown on GaAs(210) by molecular beam epitaxy. With reducing the thickness of GaAs interlayer spacer, a transition from InGaAs quantum dashes to arrow-like nanostructures is observed by atomic force microscopy. Photoluminescence measurements reveal all the samples of different spacers with good optical properties. By adjusting the InGaAs coverage, both one-dimensional and two-dimensional lateral ordering of InGaAs/GaAs(210) nanostructures are achieved

    The relation between athletic sports and prevalence of amenorrhea and oligomenorrhea in Iranian female athletes

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    <p>Abstract</p> <p>Background</p> <p>In 1992, the concept of female athlete triad was introduced to describe the interrelated problems of amenorrhea, eating disorders and osteoporosis seen in female athletes. To gain a clearer picture of amenorrhea/oligomenorrhea in Iran, one of the main components of the female athlete triad, we therefore established this study on the prevalence of amenorrhea/oligomenorrhea in elite Iranian female athletes, also evaluating the risk factors of these disorders in the same population.</p> <p>Methods</p> <p>This study performed as a cross-sectional study. All elite Iranian female athletes of 34 sports federation, including female athletes in national teams and medalists of Tehran were invited to participate. A total of 788 (95% response rate) returned the questionnaires and were examined. Younger athletes under the age of menarche were excluded. Each athlete completed a self-administered questionnaire, which covered the following questions about participant's demographic information, athletic history, history of injuries and menstrual pattern. In order to diagnose the causes of amenorrhea/Oligomenorrhea including polycystic ovary syndrome(PCOS), participants with amenorrhea/Oligomenorrhea underwent further investigation. They were evaluated by following Para clinic investigation, and an ultrasonographic study of ovary.</p> <p>Results</p> <p>The age ranged from 13–37 (mean = 21.1, SD = 4.5). Seventy one (9.0%) individuals had amenorrhea/oligomenorrhea, among those, 11 (15.5%) had PCOS.</p> <p>There was also a positive association between amenorrhea/oligomenorrhea and the following: age under 20 OR; 2.67, 95%CI(1.47 – 4.85), weight class sports OR; 2.09, 95%CI(1.15 – 3.82), endurance sports OR; 2.89, 95%CI(1.22 – 6.84), late onset of menarche OR; 3.32 95%CI(1.04–10.51), and use of oral contraceptive pills OR; 6.17, 95%CI(3.00 – 12.69). Intensity of training sport or BMI were not risk factors.</p> <p>Conclusion</p> <p>These findings support the previous findings in the literature that the prevalence of amenorrhea/oligomenorrhea is high in athletes. Furthermore, we provided the first report on the prevalence of PCOS in female athletes with amenorrhea/oligomenorrhea. Athletes would be greatly benefited by greater general awareness about the complications of amenorrhea/oligomenorrhea.</p> <p>To increase awareness of exercise-associated menstrual cycle irregularities, it is necessary to design complete and comprehensive education programs for female athletes, their parents, their coaches, and the relevant authorities.</p

    Depression and sickness behavior are Janus-faced responses to shared inflammatory pathways

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    It is of considerable translational importance whether depression is a form or a consequence of sickness behavior. Sickness behavior is a behavioral complex induced by infections and immune trauma and mediated by pro-inflammatory cytokines. It is an adaptive response that enhances recovery by conserving energy to combat acute inflammation. There are considerable phenomenological similarities between sickness behavior and depression, for example, behavioral inhibition, anorexia and weight loss, and melancholic (anhedonia), physio-somatic (fatigue, hyperalgesia, malaise), anxiety and neurocognitive symptoms. In clinical depression, however, a transition occurs to sensitization of immuno-inflammatory pathways, progressive damage by oxidative and nitrosative stress to lipids, proteins, and DNA, and autoimmune responses directed against self-epitopes. The latter mechanisms are the substrate of a neuroprogressive process, whereby multiple depressive episodes cause neural tissue damage and consequent functional and cognitive sequelae. Thus, shared immuno-inflammatory pathways underpin the physiology of sickness behavior and the pathophysiology of clinical depression explaining their partially overlapping phenomenology. Inflammation may provoke a Janus-faced response with a good, acute side, generating protective inflammation through sickness behavior and a bad, chronic side, for example, clinical depression, a lifelong disorder with positive feedback loops between (neuro)inflammation and (neuro)degenerative processes following less well defined triggers

    Restriction of meat, fish, and poultry in omnivores improves mood: A pilot randomized controlled trial

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    <p>Abstract</p> <p>Background</p> <p>Omnivorous diets are high in arachidonic acid (AA) compared to vegetarian diets. Research shows that high intakes of AA promote changes in brain that can disturb mood. Omnivores who eat fish regularly increase their intakes of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), fats that oppose the negative effects of AA in vivo. In a recent cross-sectional study, omnivores reported significantly worse mood than vegetarians despite higher intakes of EPA and DHA. This study investigated the impact of restricting meat, fish, and poultry on mood.</p> <p>Findings</p> <p>Thirty-nine omnivores were randomly assigned to a control group consuming meat, fish, and poultry daily (OMN); a group consuming fish 3-4 times weekly but avoiding meat and poultry (FISH), or a vegetarian group avoiding meat, fish, and poultry (VEG). At baseline and after two weeks, participants completed a food frequency questionnaire, the Profile of Mood States questionnaire and the Depression Anxiety and Stress Scales. After the diet intervention, VEG participants reduced their EPA, DHA, and AA intakes, while FISH participants increased their EPA and DHA intakes. Mood scores were unchanged for OMN or FISH participants, but several mood scores for VEG participants improved significantly after two weeks.</p> <p>Conclusions</p> <p>Restricting meat, fish, and poultry improved some domains of short-term mood state in modern omnivores. To our knowledge, this is the first trial to examine the impact of restricting meat, fish, and poultry on mood state in omnivores.</p

    Effect of ranitidine on acetaminophen-induced hepatotoxicity in dogs

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    The effect of ranitidine administration upon the hepatotoxic effect produced by a multidose acetaminophen administration regimen was examined. Seventy-two dogs received three subcutaneous injections of acetaminophen (750, 200, 200 mg/kg body wt) in DMSO (600 mg/ml) at time zero, 9 hr later, and 24 hr after the first dose. Ten control animals (group I) were not given ranitidine, the remaining 62 dogs received an intramus-cular injection of ranitidine 30 min before each acetaminophen dose. Three different doses of ranitidine were used (mg/kg body wt): 50 mg, group II (33 dogs); 75 mg, group III (14 dogs); 120 mg, group IV (15 dogs). Ranitidine reduced the expected acetaminophen-induced hepatoxicity in a dose-response manner. Moreover, a significant correlation was found between the ranitidine dose and the survival rate, as evidenced by transaminase levels in the serum and histology of the liver. This model of fulminant hepatic failure induced by acetaminophen and its modulation with ranitidine provides clinical investigators with a research tool that will be useful in the future investigation of putative medical and surgical therapies being investigated for use in the clinical management of fulminant hepatic failure. Because of the size of the animal used in this model, frequent and serial analyses of blood and liver were available for study to determine the effect of therapy within a given animal as opposed to within groups of animals. © 1990 Plenum Publishing Corporation

    What we talk about when we talk about "global mindset": managerial cognition in multinational corporations

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    Recent developments in the global economy and in multinational corporations have placed significant emphasis on the cognitive orientations of managers, giving rise to a number of concepts such as “global mindset” that are presumed to be associated with the effective management of multinational corporations (MNCs). This paper reviews the literature on global mindset and clarifies some of the conceptual confusion surrounding the construct. We identify common themes across writers, suggesting that the majority of studies fall into one of three research perspectives: cultural, strategic, and multidimensional. We also identify two constructs from the social sciences that underlie the perspectives found in the literature: cosmopolitanism and cognitive complexity and use these two constructs to develop an integrative theoretical framework of global mindset. We then provide a critical assessment of the field of global mindset and suggest directions for future theoretical and empirical research

    Clinical and molecular characterization of a transmitted reciprocal translocation t(1;12)(p32.1;q21.3) in a family co-segregating with mental retardation, language delay, and microcephaly

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    <p>Abstract</p> <p>Background</p> <p>Chromosome translocation associated with neurodevelopmental disorders provides an opportunity to identify new disease-associated genes and gain new insight into their function. During chromosome analysis, we identified a reciprocal translocation between chromosomes 1p and 12q, t(1; 12)(p32.1; q21.3), co-segregating with microcephaly, language delay, and severe psychomotor retardation in a mother and her two affected boys.</p> <p>Methods</p> <p>Fluorescence in situ hybridization (FISH), long-range PCR, and direct sequencing were used to map the breakpoints on chromosomes 1p and 12q. A reporter gene assay was conducted in human neuroblastoma (SKNSH) and Chinese hamster ovary (CHO) cell lines to assess the functional implication of the fusion sequences between chromosomes 12 and 1.</p> <p>Results</p> <p>We determined both breakpoints at the nucleotide level. Neither breakpoint disrupted any known gene directly. The breakpoint on chromosome 1p was located amid a gene-poor region of ~ 1.1 Mb, while the breakpoint on chromosome 12q was located ~ 3.4 kb downstream of the ALX1 gene, a homeobox gene. In the reporter gene assay, we discovered that the fusion sequences construct between chromosomes 12 and 1 had a ~ 1.5 to 2-fold increased reporter gene activity compared with the corresponding normal chromosome 12 sequences construct.</p> <p>Conclusion</p> <p>Our findings imply that the translocation may enhance the expression of the ALX1 gene via the position effect and result in the clinical symptoms of this family. Our findings may also expand the clinical phenotype spectrum of ALX1-related human diseases as loss of the ALX1 function was recently reported to result in abnormal craniofacial development.</p

    Pediatric DXA: technique and interpretation

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    This article reviews dual X-ray absorptiometry (DXA) technique and interpretation with emphasis on the considerations unique to pediatrics. Specifically, the use of DXA in children requires the radiologist to be a “clinical pathologist” monitoring the technical aspects of the DXA acquisition, a “statistician” knowledgeable in the concepts of Z-scores and least significant changes, and a “bone specialist” providing the referring clinician a meaningful context for the numeric result generated by DXA. The patient factors that most significantly influence bone mineral density are discussed and are reviewed with respect to available normative databases. The effects the growing skeleton has on the DXA result are also presented. Most important, the need for the radiologist to be actively involved in the technical and interpretive aspects of DXA is stressed. Finally, the diagnosis of osteoporosis should not be made on DXA results alone but should take into account other patient factors
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