2,128 research outputs found

    Thin endometrial lining:is it more prevalent in patients utilizing preimplantation genetic testing for monogenic disease (PGT-M) and related to prior hormonal contraceptive use?

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    STUDY QUESTION: Is a thin endometrial lining before ovulation triggering more prevalent in patients utilizing preimplantation genetic testing for monogenic disease (PGT-M) compared to the regular IVF/ICSI population and is this associated with prior hormonal contraceptive use? SUMMARY ANSWER: Thin (1 year prior to treatment). Endometrial thickness was routinely measured on the day of hCG triggering or 1 day prior. The prevalence of an endometrial lining or 8 mm (20.0% vs 1.7%, mean difference 18.3%, 95% CI: 2.3, 34.3%). A trend towards lower birth weight and gestation- and gender-adjusted birth weight (z-score) was also found in this group. No statistically significant differences were detected in pregnancy rate, live birth rate, or incidence of preterm delivery or SGA. Within the control group, no statistically significant differences were found in outcomes between patients with an endometrial lining 8 mm. LIMITATIONS, REASONS FOR CAUTION: The study is retrospective. Various types of hormonal contraceptives were reported which possibly exert different effects on the endometrial lining. In relation to pregnancy outcome measures, numbers were very limited; therefore, no firm conclusions should be drawn. WIDER IMPLICATIONS OF THE FINDINGS: This study provides further insight into the role of prior hormonal contraceptive use as a possible contributor to the occurrence of thin endometrial lining during ART treatment. Future studies should provide more information on its clinical relevance, to determine whether PGT-M patients can be reassured, or should be counselled to stop hormonal contraceptive use and change to an alternative contraceptive method prior to PGT treatment. STUDY FUNDING/COMPETING INTERESTS: No specific funding was used and no conflicts of interests are declared. TRIAL REGISTRATION NUMBER: N/A

    Actions of metformin and statins on lipid and glucose metabolism and possible benefit of combination therapy

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    Patients with diabetes type 2 have an increased risk for cardiovascular disease and commonly use combination therapy consisting of the anti-diabetic drug metformin and a cholesterol-lowering statin. However, both drugs act on glucose and lipid metabolism which could lead to adverse effects when used in combination as compared to monotherapy. In this review, the proposed molecular mechanisms of action of statin and metformin therapy in patients with diabetes and dyslipidemia are critically assessed, and a hypothesis for mechanisms underlying interactions between these drugs in combination therapy is developed

    Low-level contrast statistics are diagnostic of invariance of natural textures

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    Texture may provide important clues for real world object and scene perception. To be reliable, these clues should ideally be invariant to common viewing variations such as changes in illumination and orientation. In a large image database of natural materials, we found textures with low-level contrast statistics that varied substantially under viewing variations, as well as textures that remained relatively constant. This led us to ask whether textures with constant contrast statistics give rise to more invariant representations compared to other textures. To test this, we selected natural texture images with either high (HV) or low (LV) variance in contrast statistics and presented these to human observers. In two distinct behavioral categorization paradigms, participants more often judged HV textures as “different” compared to LV textures, showing that textures with constant contrast statistics are perceived as being more invariant. In a separate electroencephalogram (EEG) experiment, evoked responses to single texture images (single-image ERPs) were collected. The results show that differences in contrast statistics correlated with both early and late differences in occipital ERP amplitude between individual images. Importantly, ERP differences between images of HV textures were mainly driven by illumination angle, which was not the case for LV images: there, differences were completely driven by texture membership. These converging neural and behavioral results imply that some natural textures are surprisingly invariant to illumination changes and that low-level contrast statistics are diagnostic of the extent of this invariance

    Isotope effects in underdoped cuprate superconductors: a quantum phenomenon

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    We show that the unusual doping dependence of the isotope effects on transition temperature and zero temperature in - plane penetration depth naturally follows from the doping driven 3D-2D crossover, the 2D quantum superconductor to insulator transition (QSI) in the underdoped limit and the change of the relative doping concentration upon isotope substitution. Close to the QSI transition both, the isotope coefficient of transition temperature and penetration depth approach the coefficient of the relative dopant concentration, and its divergence sets the scale. These predictions are fully consistent with the experimental data and imply that close to the underdoped limit the unusual isotope effect on transition temperature and penetration depth uncovers critical phenomena associated with the quantum superconductor to insulator transition in two dimensions.Comment: 6 pages, 3 figure

    Mapping cells and sub-cellular organelles on 2-D gels: ‘new tricks for an old horse’

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    AbstractNowadays, investigators in all fields are faced with the identification of unknown, up- or down-regulated, modified proteins that they are trying to identify. Two-dimensional (2-D) gel electrophoresis, with its ability to resolve several thousand proteins, is an extremely powerful technique. The current resolution and reproducibility of 2-D gel technology and the establishment of computer assisted 2-D gel protein databases have paved new ways for the identification of proteins

    CO2 Conversion in Nonuniform Discharges: Disentangling Dissociation and Recombination Mechanisms

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    Motivated by environmental applications such as synthetic fuel synthesis, plasma-driven conversion shows promise for efficient and scalable gas conversion of CO2 to CO. Both discharge contraction and turbulent transport have a significant impact on the plasma processing conditions, but are, nevertheless, poorly understood. This work combines experiments and modeling to investigate how these aspects influence the CO production and destruction mechanisms in the vortex-stabilized CO2 microwave plasma reactor. For this, a two-dimensional axisymmetric tubular chemical kinetics model of the reactor is developed, with careful consideration of the nonuniform nature of the plasma and the vortex-induced radial turbulent transport. Energy efficiency and conversion of the dissociation process show a good agreement with the numerical results over a broad pressure range from 80 to 600 mbar. The occurrence of an energy efficiency peak between 100 and 200 mbar is associated with a discharge mode transition. The net CO production rate is inhibited at low pressure by the plasma temperature, whereas recombination of CO to CO2 dominates at high pressure. Turbulence-induced cooling and dilution of plasma products limit the extent of the latter. The maxima in energy efficiency observed experimentally around 40% are related to limits imposed by production and recombination processes. Based on these insights, feasible approaches for optimization of the plasma dissociation process are discussed.</p

    The Duodenum harbors a Broad Untapped Therapeutic Potential

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    The gastroenterologist, when performing an esophagogastroduodenoscopy, is the only medical care provider with easy access to the duodenum (Figure 1A). This simple fact is pivotal in this article that discusses why the duodenum has become such an important anatomic region of interest. Recent insights have revealed the critical physiologic and pathophysiologic role of the small bowel in metabolic homeostasis and its potential role as a driver of obesity, insulin resistance, and subsequent type 2 diabetes mellitus (T2DM). Although the other parts of the small bowel cannot be ignored when describing the potential mechanisms involved in the development of metabolic diseases and T2DM, the excellent endoscopic accessibility of the duodenum makes it a prime target for disease-modifying intervention

    Intraoperative neurophysiological monitoring during scoliosis surgery in patients with Duchenne muscular dystrophy

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    PURPOSE: Little is known about the reliability and value of intraoperative neurophysiological monitoring (IONM) in patients with Duchenne muscular dystrophy (DMD) undergoing scoliosis correction surgery. The aim of this study was to investigate the feasibility of IONM and the cortical excitability in these patients. METHODS: Fifteen patients with DMD and scoliosis and 15 patients with adolescent idiopathic scoliosis (AIS) underwent scoliosis correction surgery with the use of IONM. IONM consisted of transcranial electrical stimulation motor evoked potential (Tc-MEP) and somatosensory evoked potential (SSEP) monitoring. The highest Tc-MEP amplitudes were collected to test the feasibility. Preoperative compound muscle action potentials (CMAPs) and transcranial magnetic stimulation (TMS)-MEPs were recorded to test the cortical excitability. SSEPs were scored as elicitable or not elicitable. RESULTS: Tc-MEP amplitudes were significantly lower in the DMD group for both the gastrocnemius and tibialis anterior muscles. However, the abductor hallucis muscle had similar amplitudes in both the DMD as the AIS group. TMS/CMAP and Tc-MEP/CMAP ratios were similar in the DMD and AIS group (P = 0.126 and P = 0.792 respectively). CONCLUSIONS: Tc-MEP and SSEP monitoring is feasible, particularly when Tc-MEPs are recorded from the abductor hallucis muscle in patients with DMD. Similar TMS/CMAP and Tc-MEP/CMAP ratios show that there were no differences observed in cortical excitability between the groups. IONM seems a feasible and valuable neurophysiological tool to signal possible surgically induced damage to the spinal cord during scoliosis correction surgery in patients with DMD
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