Elastic Moduli of Non-Chiral Singe-Walled Silicon Carbide Nanotubes: Numerical Simulation Study

Silicon carbide nanotubes (SiCNTs) have generated significant research interest due to their potential use in the fabrication of electronic and optoelectronic nanodevices and biosensors. The exceptional chemical, electrical and thermal properties of SiCNTs are beneficial for their application in high-temperature and harsh-environments. In view of the limited thermal stability of carbon nanotubes, they can be replaced by silicon carbide nanotubes in reinforced composites, developed for operations at high temperatures. However, fundamentally theoretical studies of the mechanical properties of the silicon carbide nanotubes are at an early stage and their results are still insufficient for designing and exploiting appropriate nanodevices based on SiCNTs and reinforced composites. In this context, the present study deals with the determination of Young’s and shear moduli of non-chiral single-walled silicon carbide nanotubes, using a three-dimensional finite element model.     

SnS2 Nanosheets as a Template for 2D SnO2 Sensitive Material: Nanostructure and Surface Composition Effects

Two-dimensional nanosheets of semiconductor metal oxides are considered as promising for use in gas sensors, because of the combination of a large surface-area, high thermal stability and high sensitivity, due to the chemisorption mechanism of gas detection. In this work, 2D SnO₂ nanosheets were synthesized via the oxidation of template SnS₂ nanosheets obtained by surfactant-assisted one-pot solution synthesis. The 2D SnO₂ was characterized using transmission and scanning electron microscopy (TEM, SEM), X-ray diffraction (XRD), low-temperature nitrogen adsorption, X-ray photoelectron spectroscopy (XPS) and IR spectroscopy. The sensor characteristics were studied when detecting model gases CO and NH₃ in dry (RH₂₅ = 0%) and humid (RH₂₅ = 30%) air. The combination of high specific-surface-area and increased surface acidity caused by the presence of residual sulfate anions provides a high 2D SnO₂ sensor’s signal towards NH₃ at a low temperature of 200 °C in dry air, but at the same time causes an inversion of the sensor response when detecting NH₃ in a humid atmosphere. To reveal the processes responsible for sensor-response inversion, the interaction of 2D SnO₂ with ammonia was investigated using diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) in dry and humid air at temperatures corresponding to the maximum “positive” and maximum “negative” sensor response.     

Correlation between oocyte morphology and the embryo aneuploidy rate in IVF cycles

Abstract

Purpose: To evaluate the aneuploidy rates of 13, 18, and 21 and the X and Y chromosomes in embryos from patients with morphologically normal oocytes and different oocyte dysmorphisms.

Methods: This prospective cohort study included 84 patients treated with in vitro fertilization (IVF) at a single academic center. The patients were divided into the following three groups: group 1 – women with cytoplasmic dysmorphisms (n?=?28), group 2 – women with extracytoplasmic dysmorphisms (n?=?28), and group 3 – women with morphologically normal oocytes (n?=?28). One blastomere from each embryo was analyzed for aneuploidies of chromosomes 13, 18, 21, X, and Y.

Results: The highest prevalence of aneuploid embryos was observed in the group 1 (68.4%) followed by the group 2 (38.9%) and the group 3 (31.3%) (р?<?0.0001). The adjusted OR for receiving an aneuploid embryo in the case of cytoplasmic dysmorphism was 3.6 (95% CI?=?1.8; 7.2), in the case of extracytoplasmic dysmorphisms – 1.3 (95% CI?=?0.7; 2.1).

Conclusions: Women with morphological oocyte abnormalities are at risk for developing aneuploid embryos during IVF cycles. We recommend that woman with cytoplasmic oocyte dysmorphisms receive additional genetic counseling to define the indications for the genetic screening of embryos.     

Summary of worldwide pediatric malignancies reported after exposure to etanercept

Background  

Concerns have been raised about a potential link between the use of TNF inhibitors and development of malignancy in the pediatric population. We examined the worldwide experience of etanercept use in pediatric patients and the occurrence of malignancies as reported from clinical trials, registry studies, post-marketing surveillance, and published scientific literature.     

Elevated tryptase levels are associated with greater bone density in a cohort of patients with mastocytosis

BACKGROUND: Mastocytosis is associated with a pathological increase in tissue mast cells. Associated skeletal problems include a decrease in bone density and pathological fractures. METHODS: In order to explore the relationship between bone density and the severity of mastocytosis, 21 patients with mastocytosis who underwent dual-energy X-ray absorptiometry were entered into this study. Correlation coefficients were computed between Z-scores and demographic, clinical and laboratory data. Femoral neck Z-scores correlated with serum tryptase levels when all the patients were considered (p=0.029). RESULTS AND CONCLUSION: Patients with less severe disease had significantly lower values at the L1-L4 spine (p=0.046) and femoral neck (p=0.029) Z-scores compared to patients with more severe disease. Most patients who had low Z-scores (between -1 and -2.5) were under 50 years of age, had less severe disease and had lower serum tryptase levels. A history of gastroesophageal reflux disease and a history of hypotensive episodes correlated with lower L1-L4 spine Z-scores (p<0.05). Thus, patients with less severe disease and lower serum tryptase levels should in particular have their bone density determined with treatment appropriate to the findings.     

Frequency of known gene rearrangements in endometrial stromal tumors

Translocations resulting in gene fusion are characteristic of endometrial stromal tumors (ESTs). Rearrangements of JAZF1, SUZ12, PHF1, and EPC1 have been reported in endometrial stromal nodules (ESNs), endometrial stromal sarcomas (ESSs), and rarely in undifferentiated endometrial sarcomas (UESs). Detection of JAZF1, SUZ12, EPC1, and PHF1 rearrangement by fluorescence in situ hybridization was performed on tissue microarrays consisting of 94 ESTs of classic and variant morphology (20 ESNs, 43 primary uterine ESSs, 15 metastatic uterine ESSs, 4 primary extrauterine ESSs, 7 primary uterine UESs, and 5 unclassified ESTs), 16 Müllerian adenosarcomas, 2 malignant mixed Müllerian tumors, 2 uterine tumors resembling ovarian sex-cord tumors, 2 highly cellular leiomyomas, 1 leiomyosarcoma, and 7 polypoid endometriosis. Rearrangements were detected in 42 of 78 (54%) uterine ESTs, with JAZF1-SUZ12 fusion found in 50% of ESNs and in 33% of ESSs and JAZF1-PHF1 and EPC1-PHF1 fusions found in 1% and <1% of ESSs, respectively. PHF1 and JAZF1 were rearranged with unknown partners in 8 uterine ESTs. JAZF1-SUZ12 fusion, EPC1-PHF1 fusion, and PHF1 rearrangement were found in 3 extrauterine ESSs, whereas no rearrangements were observed in UESs or in any other non-EST studied. Our data confirm that gene rearrangements are present in more than 50% of uterine ESTs, with JAZF1-SUZ12 fusion being the most common, followed by rare EPC1-PHF1 and JAZF1-PHF1 fusions. The presence of identical gene rearrangements in both uterine and extrauterine ESTs suggests a similar pathogenesis. The presence of detectable gene rearrangements in uterine ESS may predict better patient outcome.