280 research outputs found

    Optimisation of the shear forming process by means of multivariate statistical methods

    Get PDF
    Shear forming is a versatile process for manufacturing complex lightweight components which are required in increasing numbers by many different industries. Inherent advantages of the process are simple tooling, low tool costs, good external and internal surface quality, close dimensional accuracy, and good mechanical properties of the components. In times of free market economy, it is necessary to on the one hand fulfill the increasing demands toward the quality characteristics and on the other hand to reduce the development time needed to manufacture such a high quality component. Since shear forming is a complex and sensitive process in terms of deformation characteristics this is not an easy task. To assess the overall quality of a component several, mutually contradictory, quality characteristics have to be considered simultaneously. While conventionally each characteristic is considered separately, in this paper, a statistical approach is presented which copes with the above mentioned demands and provides the opportunity for an efficient, multivariate optimisation of the process. With a minimum of statistically planned experiments, mathematical models are derived which describe the influence of the machine parameters and their interactions on quantitative as well as qualitative component characteristics. A multivariate optimisation procedure based on the concept of desirabilities is used to find the best compromise between the mutually contradictory quality characteristics. With this statistical approach a workpiece for electrical industry is manufactured which requires a very good surface quality and close geometrical tolerances. --Shear forming,experimental design,multivariate optimisation,high voltage divider

    Serum brain-derived neurotrophic factor (BDNF) is not regulated by testosterone in transmen

    Get PDF
    Brain morphology significantly differs between the sexes. It has been shown before that some of these differences are attributable to the sex-specific hormonal milieu. Brain-derived neurotrophic factor (BDNF) is involved in myriads of neuroplastic processes and shows a sexual dimorphism. Transsexual persons may serve as a model to study sex steroid-mediated effects on brain plasticity. We have recently demonstrated that serum levels of BDNF are reduced in transwomen following 12 months of cross-sex hormone treatment. We now wanted to look at the effects of testosterone treatment on BDNF in transmen. In contrast to our initial hypothesis, BDNF levels did not significantly change, despite dramatic changes in the sex-hormonal milieu. Our data indicate that testosterone does not seem to play a major role in the regulation of BDNF in females

    Effects of sex hormone treatment on the metabolic syndrome in transgender individuals : focus on metabolic cytokines

    Get PDF
    Context: Hormonal treatment in transgender persons affects many components of the metabolic syndrome (MS). Objective: To determine the role of direct hormonal effects, changes in metabolic cytokines, and body composition on metabolic outcomes. Design, Setting, and Participants: 24 transwomen and 45 transmen from the European Network for the Investigation of Gender Incongruence were investigated at baseline and after 12 months of hormonal therapy. Outcome Measures: Best predictors for changes in components of MS, applying least absolute shrinkage and selection operator regression. Results: In transwomen, a decrease in triglyceride levels was best explained by a decrease in fat mass and an increase in fibroblast growth factor 21 (FGF-21); the decrease in total and low-density lipoprotein cholesterol levels was principally due to a decrease in resistin. A decrease in high-density lipoprotein cholesterol depended on an inverse association with fat mass. In contrast, in transmen, an increase in low-density lipoprotein cholesterol was predicted by a decrease in FGF-21 and an increase in the waist/hip ratio; a decrease in the high-density lipoprotein/total cholesterol ratio depended on a decline in adiponectin levels. In transwomen, worsened insulin resistance and increased early insulin response seemed to be due to a direct treatment effect; however, improvements in hepatic insulin sensitivity in transmen were best predicted by a positive association with chemerin, resistin, and FGF-21 and were inversely related to changes in the waist/hip ratio and leptin and adipocyte fatty acid-binding protein levels. Conclusions: The effects of hormonal therapy on different components of the MS are sex-specific and involve a complex interplay of direct hormonal effects, changes in body composition, and metabolic cytokine secretion

    Ectopic Prostate Tissue in the Uterine Cervix of a Female with Non-Classic Congenital Adrenal Hyperplasia-A Case Report

    Get PDF
    Introduction: The occurrence of ectopic prostate tissue in the female genital tract is rare and has only been described sporadically. The origin of these lesions is unclear, but their appearance seems to be associated with various forms of androgen excess, including androgen therapy for transgender treatment or disorders of sex development, such as classic congenital adrenal hyperplasia (CAH). This is the first described case of ectopic prostate tissue in the cervix uteri of a 46,XX patient with a confirmed diagnosis of non-classic CAH due to 21-OHD and a history of mild adrenal androgen excess. Case presentation: We describe a 34-year-old patient with a genetic diagnosis of non-classic CAH due to 21-hydroxylase deficiency (21-OHD) with a female karyo- and phenotype and a history of mild adrenal androgen excess. Due to dysplasia in the cervical smear, conization had to be performed, revealing ectopic prostate tissue in the cervix uteri of the patient. Conclusions: An association between androgen excess and the occurrence of prostate tissue is likely and should therefore be considered as a differential diagnosis for atypical tissue in the female genital tract

    Sleep patterns in patients treated for non-secreting intra- and parasellar tumors

    Get PDF
    PURPOSE: In this study we evaluate sleep patterns of patients treated for non-secreting intra- and parasellar tumors and age- and sex-matched healthy controls. METHODS: We conducted a self-report cross-sectional case-control study with 104 patients treated for non-secreting intra- and parasellar tumors and 1800 healthy controls in an 1:8 matching. All subjects answered the Munich ChronoType Questionnaire, whereas patients were provided the Pittsburgh Sleep Quality Index, the Epworth Sleepiness Scale, the Short-Form 36 Health survey, the Beck Depression Inventory and the State-Trait Anxiety Inventory additionally. RESULTS: Patients treated for non-secreting intra- and parasellar tumors go to bed earlier, fall asleep earlier, need less time to prepare to sleep but also to get up. Additionally, they lie and sleep longer. The subgroup analysis showed that patients with secondary adrenal insufficiency compared to controls experienced shorter daily light exposure and longer sleep latency. Higher hydrocortisone dose (>20mg) was associated with worse score in global, physical and mental health, shorter time to prepare to sleep, earlier sleep onset and longer sleep duration. CONCLUSION: Our study shows that patients treated for non-secreting intra- and parasellar tumors, even if successfully treated, experience altered sleep patterns compared to controls. We suggest that managing clinicians should enlighten these possible sleep alterations to their patients and use specific questionnaires to document sleep disturbances. Additionally, when treating patients surgically, especially by transcranial approach, damaging the suprachiasmatic nucleus should be avoided. Furthermore, circadian hydrocortisone replacement therapy ideally with dual-release hydrocortisone - if possible, in a dose not more than 20mg daily - that resembles physiological cortisol levels more closely may be beneficial and could improve sleep patterns and sleep-related quality of life

    Integrated stratigraphy (radiolarians, calcareous nannofossils, carbon and strontium isotopes) of the Sinemurian–Pliensbachian transition at Mt. Rettenstein, Northern Calcareous Alps, Austria

    Get PDF
    A 95 m thick succession of grey siliceous limestone and marl on Mount Rettenstein in the Northern Calcareous Alps allowed us to study well-preserved and diverse radiolarian assemblages across the Sinemur- ian–Pliensbachian boundary. The distribution of 31 most characteristic radiolarian species is presented. Am- monites of the Jamesoni Subzone, the topmost subzone of the Jamesoni Zone, have been previously found in the upper part of the section. The radiolarian data are complemented with calcareous nannofossil biostratigraphy, and carbon and strontium isotope analyses of bulk carbonate samples. A negative stable carbon isotope excursion (CIE) occurs in the middle part of the section and is correlated to the supraregional Sinemurian – Pliensbachian Boundary Event. Radiolarian assemblages below the negative CIE belong to the Canutus rockfishensis – Wrangellium thurstonense and Jacus? sandspitensis radiolarian zones. Katroma clara and several other species belonging to the subsequent Canutus tipperi – Katroma clara Radiolarian Zone first occur at the beginning of the negative CIE. The first occurrence of the nannofossil Similiscutum cruciulus, which defines the base of the NJ4 Calcareous Nannofossil Zone, was recognized near the top of the negative CIE, 10 m above the inferred stage boundary. The strontium isotope ratio is due to diagenetic alteration of bulk micrite systematically shifted to higher values, but clearly decreases across the stage boundary. This decrease is compatible with the trend of the standard 87Sr/86Sr curve established in skeletal calcite. This is the first time radiolarian zones across the Sinemurian–Pliensbachian boundary in Europe can be tied to calcareous nannofossil zones and chemostratigraphy and also calibrated to chronostratigraphy. These results contribute to the stability of Lower Jurassic radiolarian zones and will allow the recognition of the Sinemur- ian–Pliensbachian boundary in deep-marine successions where ammonites are absent

    Psychopathological Profiles in Transsexuals and the Challenge of Their Special Status among the Sexes

    Get PDF
    OBJECTIVE:Investigating psychopathological profiles of transsexuals raises a very basic methodological question: are control groups, which represent the biological or the phenotypic sex, most suited for an optimal evaluation of psychopathology of transsexuals? METHOD:Male-to-female (MtF) (n=52) and female-to-male transsexuals (FtM) (n=32), receiving cross-sex hormone treatment, were compared with age matched healthy subjects of the same genetic sex (n=178) and with the same phenotypic sex (n=178) by means of the Symptom Check List-90-Revisited instrument (SCL-90-R). We performed analyses of covariance (ANCOVA) to test for group and sex effects. Furthermore, we used a profile analysis to determine if psychopathological symptom profiles of transsexuals more closely resemble genotypic sex or phenotypic sex controls. RESULTS:Transsexual patients reported more symptoms of psychopathological distress than did healthy control subjects in all subscales of the SCL-90-R (all p<0.001), regardless of whether they were compared with phenotype or genotype matched controls. Depressive symptoms were more pronounced in MtF than in FtM (SCL-90-R score 0.85 vs. 0.45, p = 0.001). We could demonstrate that FtM primarily reflect the psychopathological profile of biological males rather than that of biological females (r = 0.945), while MtF showed a slightly higher profile similarity with biological females than with biological males (r = 0.698 vs. r = 0.685). CONCLUSION:Our findings suggest that phenotypic sex matched controls are potentially more appropriate for comparison with the psychopathology of transsexual patients than are genetic sex matched controls

    Shorter telomeres associated with high doses of glucocorticoids: the link to increased mortality?

    Get PDF
    Objective: Patients with non-functioning pituitary adenomas exhibit high morbidity and mortality rates. Growth hormone deficiency and high doses of glucocorticoid substitution therapy have been identified as corresponding risk factors. Interestingly, high levels of endogenous cortisol in, e.g., patients with post-traumatic stress disorder or patients with Cushing's disease have been linked to shorter telomere length. Telomeres are noncoding DNA regions located at the end of chromosomes consisting of repetitive DNA sequences which shorten with aging and hereby determine cell survival. Therefore, telomere length can serve as a predictor for the onset of disease and mortality in some endocrine disorders (e.g., Cushing's disease). Design/methods: Here, we examine telomere length from blood in patients (n=115) with non-functioning pituitary adenomas (NFPA) in a cross-sectional case-control (n= 106, age-, gender-matched) study using qPCR. Linear regression models were used to identify independent predictors of telomere length. Results: We show that patients with NFPA exhibited shorter telomeres than controls. No significant association of indices of growth hormone deficiency (IGF-1-level-SDS, years of unsubstituted growth hormone deficiency etc.) with telomere length was detected. Interestingly, linear regression analysis showed that hydrocortisone replacement dosage in patients with adrenal insufficiency (n=52) was a significant predictor for shorter telomere length (beta=0.377;P=0.018) independent of potential confounders (gender, age, BMI, arterial hypertension, systolic blood pressure, number of antihypertensive drugs, total leukocyte count, waist-to-hip ratio, waist circumference, diabetes mellitus type 2, HbA1c, current statin use). Median split analysis revealed that higher hydrocortisone intake (>20 mg) was associated with significantly shorter telomeres. Conclusion: These observations strengthen the importance of adjusted glucocorticoid treatment in NFPA patients with respect to morbidity and mortality rates
    • 

    corecore