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Objective: The study aimed to determine the relationship between body mass index (BMI) and the risk of acute aortic syndrome (AAS) with preoperative oxygenation impairment. Methods: A meta-analysis of published observational studies involving BMI and AAS with preoperative oxygenation impairment was conducted. A total of 230 patients with AAS were enrolled for retrospective analysis. All patients were divided into 2 groups (Non-oxygenation impairment group and Oxygenation impairment group). Logistic regression analysis was performed to assess the relation between BMI and the risk of preoperative oxygenation impairment after the onset of AAS. Dose-response relationship curve and subgroup analysis were conducted to test the reliability of BMI as an independent factor of it. Results: For the meta-analysis, the quantitative synthesis indicated that excessive BMI increased the risk of preoperative oxygenation impairment (OR: 1.30, 95% CI: 1.05-1.60, Pheterogeneity = 0.001). For the retrospective analysis, a significant association was observed after adjusting for a series of variables. BMI was significantly related to preoperative oxygenation impairment after the onset of AAS (OR: 1.34, 95% CI: 1.15-1.56, p <0.001), and compared with normal weight group (18.5 kg/m² = BMI < 23.0 kg/m²), the individuals with excessive BMI were at higher risk of preoperative oxygenation impairment for the obese group (BMI = 25 kg/m²) (OR: 17.32, 95% CI: 4.03-74.48, p <0.001). A J-shape curve in dose-response relationship analysis further confirmed their positive correlation. Subgroup analysis showed that diastolic blood pressure DBP) = 90mmHg carried an excess risk of preoperative oxygenation impairment in obese patients. Conclusion: Excessive BMI was an independent risk factor for AAS with preoperative oxygenation impairment. [ABSTRACT FROM AUTHOR]

Objective: Oxygenation impairment is a common complication of acute aortic syndrome (AAS) patients after surgical repair. The aim of this study is to identify the relationship between body mass index (BMI) and the risk of postoperative oxygenation impairment in AAS patients. Methods: A total of 227 consecutive patients who were diagnosed as AAS and underwent surgical repair were recruited. They were divided into two groups based on the postoperative oxygenation impairment (non-oxygenation impairment group and oxygenation impairment group). Logistic regression was conducted to evaluate the association between BMI and the risk of oxygenation impairment after surgery. Dose-response curve and subgroup analysis were used to test the reliability of the results of regression analysis. A meta-analysis was then performed to further confirm these results using Pubmed, Embase, and Web of Science databases. Results: For the retrospective study, a significant association was observed after adjusting for a series of variables. BMI was significantly correlated with postoperative oxygenation impairment in patients with AAS (OR, 95% CI, P: 1.27, 1.17-1.46, 0.001). Compared with the normal weight group (18.5 kg/m² ≤ BMI <23.0 kg/m²), patients with excessive BMI were at a higher risk of oxygenation impairment for the overweight group (23.0 kg/m² ≤ BMI <25 kg/ m²) and obesity group (BMI ≥25 kg/m2) (OR, 95% CI, P: 4.96,1.62-15.15, 0.005; 9.51, 3.06-29.57, <0.001). The dose-response curve showed that the risk of oxygenation impairment after surgery increased with the increased BMI. Besides, subgroup analysis showed that AAS patients who have an excess weight with a TNF-α ≥ 8.1pg/ml carried an excess risk of postoperative oxygenation impairment. For the meta-analysis, the pooled result also indicated that AAS patients with high BMI had a significantly increased risk of oxygenation impairment after surgery (OR, 95% CI, P: 1.40, 1.18-1.66, 0.001). Conclusion: Excessive BMI was an independent risk factor for AAS with postoperative oxygenation impairment. [ABSTRACT FROM AUTHOR]

The aim of the present study was to investigate the role of miR-31 in Th22 differentiation in coronary heart disease (CHD). Th22 frequencies in peripheral blood of CHD patients and controls as well as in CD4+ T cells were detected by flow cytometry. The mRNA expression of Th22-associated transcription factor aryl hydrocarbon receptor (AHR) and Th22-effector cytokine interleukin (IL)-22, as well as miR-31 were examined by quantitative real-time PCR (qRT-PCR). The protein level of BTB domain and CNC homolog 2 (Bach2) was measured by Western blotting. The interaction between miR-31 and Bach2 was verified using dual luciferase reporter assay. The results showed that Th22 frequency and miR-31 expression were elevated in CHD patients. Furthermore, miR-31mimic and Bach2 silencing significantly promoted Th22 frequency and the levels of AHR and IL-22 in CD4+ T cells from CHD patients. Further studies showed that miR-31 facilitated Th22 cell differentiation by targeting and inhibiting Bach2. Our data indicate that miR-31 promotes Th22 differentiation through targeting Bach2 in CHD. [ABSTRACT FROM AUTHOR]

We present a comprehensive structural characterization of ferromagnetic SiC single crystals induced by Ne ion irradiation. The ferromagnetism has been confirmed by electron spin resonance, and possible transition metal impurities can be excluded to be the origin of the observed ferromagnetism. Using X-ray diffraction and Rutherford backscattering/channeling spectroscopy, we estimate the damage to the crystallinity of SiC, which mutually influences the ferromagnetism in SiC. [ABSTRACT FROM AUTHOR]

Background Heparin-induced thrombocytopenia (HIT) in infants is a rare disorder, and the diagnosis and management of HIT still remains challenging. Argatroban is a synthetic direct thrombin inhibitor (DTI) that is widely used for treating HIT. However, little is known about the efficacy of the activated clotting time (ACT) test inmonitoring DTI treatment as an alternative to the routinely used activated partial thromboplastin time (aPTT). Methods Between July 2013 and January 2015, four infants were diagnosed with HIT after surgical correction of congenital anomalies. In all cases, heparin was used during cardiopulmonary bypass (CPB). Diagnosis of HITwas based on the "4 Ts" pretest clinical scoring system, and platelet factor 4 (PF4) antibody was detected using enzyme-linked immunosorbent assay. Argatroban was used in treating HIT. When argatroban was infused, anticoagulation tests (aPTT, prothrombin time [PT], thrombin time [TT], and fibrinogen) were performed every 4 to 12 hours. ACT was used in addition to monitor the anticoagulation effect of argatroban. The target ACT was 1.5 to 3.0 times the baseline. ACT was measured every 2 to 4 hours and remeasured 1 hour after each dosage adjustment. Results Thrombocytopenia (defined as a 50% decrease in platelet count) occurred during the 3rd to 6th day postoperatively. After the diagnosis of HIT, argatroban was started immediately, and platelet counts stabilized and gradually increased. Anticoagulation effect of argatroban was successful monitored by ACT and aPTT. Poor correlation between the ACT test and aPTT test (R = 0.270, p = 0.092) was noted in one patient. ACT values increased rapidly after 3 to 7 days on argatroban treatment. In most cases, low dosage of argatroban was given ranging from 0.04 to 5.00 µg/kg/min. Conclusion Argatroban may be an effective medicine in treating HIT in infants, in a reduced dosage. The great fluctuation in argatroban dosage during the course of HIT treatment necessitates close monitoring. ACT test may be reliable and convenient for monitoring HIT treatment and may contribute to positive clinical outcomes in infants. The efficacy of argatroban and the use of ACT monitoring in the management of HIT infants needs further study. [ABSTRACT FROM AUTHOR]

WTe2 is provoking immense interest owing to its extraordinary properties, such as large positive magnetoresistance, pressure-driven superconductivity and possible type-II Weyl semimetal state. Here we report results of high-pressure synchrotron X-ray diffraction (XRD), Raman and electrical transport measurements on WTe2. Both the XRD and Raman results reveal a structural transition upon compression, starting at 6.0 GPa and completing above 15.5 GPa. We have determined that the high-pressure lattice symmetry is monoclinic 1T' with space group of P21/m. This transition is related to a lateral sliding of adjacent Te-W-Te layers and results in a collapse of the unit cell volume by ∼20.5%. The structural transition also casts a pressure range with the broadened superconducting transition, where the zero resistance disappears. [ABSTRACT FROM AUTHOR]

Frustration makes a tremendous amount of degenerate ground states which provides no energy scale of its own. Any perturbation has to be considered strong and fascinating phenomena may be emergent upon relieving of frustration. Here, we report the evolution of spin phonon coupling in the frustrated spinel system Zn1-xCdxCr2Se4 (0 ≤ x ≤ 1) from magnetization, specific heat and thermal conductivity. Our results give clear evidences that the spin-orientated structural transitions decay rapidly as x going from 0 to 0.4 while the correlations between spin and lattice degrees of freedom for 0.6 ≤ x ≤ 1 become weak and can be explained in terms of the traditional magnetostriction effect. In addition, for 0 ≤ x ≤ 0.4 thermal carriers reveal strong scattering from spin fluctuations in the vicinity of TN owing to strong frustration, in stark contrast with those for 0.6 ≤ x ≤ 1 where traditional phonon-like heat conduction behaviors are observed. Moreover, it is shown that a moderate applied magnetic field can drive readily the fluctuations-scattered thermal conductivity toward traditional phonon-like one as observed in CdCr2Se4, reaching about 30% for x = 0.4 at 25 K in 1 T. Such strong field-sensitive effects may introduce new promising functionalities for potential applications. [ABSTRACT FROM AUTHOR]

As a new type of topological materials, ZrTe5 shows many exotic properties under extreme conditions. Using resistance and ac magnetic susceptibility measurements under high pressure, while the resistance anomaly near 128 K is completely suppressed at 6.2 GPa, a fully superconducting transition emerges. The superconducting transition temperature Tc increases with applied pressure, and reaches amaximumof 4.0 K at 14.6 GPa, followed by a slight drop but remaining almost constant value up to 68.5 GPa. At pressures above 21.2 GPa, a second superconducting phase with the maximum Tc of about 6.0 K appears and coexists with the original one to the maximum pressure studied in this work. In situ high-pressure synchrotron X-ray diffraction and Raman spectroscopy combined with theoretical calculations indicate the observed two-stage superconducting behavior is correlated to the structural phase transition from ambient Cmcm phase to high-pressure C2/m phase around 6 GPa, and to a mixture of two high-pressure phases of C2/m and P-1 above 20 GPa. The combination of structure, transport measurement, and theoretical calculations enable a complete understanding of the emerging exotic properties in 3D topological materials under extreme environments. [ABSTRACT FROM AUTHOR]

We have recently reported that the superconducting transition temperature of FeTe0.5Se0.5 flakes attached onto commercial Scotch tape can be enhanced by about 1-2 K due to a thermal-mismatch induced compressive strain. In this work, we further investigated the Scotch tape effect on structural variation of FeTe0.5Se0.5 and Fe1.05Te flakes by X-ray diffraction measurements. We show that for FeTe0.5Se0.5, the lattice constant c of taped flakes is elongated by about 0.5% at 15 K as compared with bulk crystal. Upon warming from 15 K, the lattice constant c of the taped flakes first levels off then displays negative thermal expansion followed by monotonic increase at temperatures above 100 K. For antiferromagnetic Fe1.05Te, the structural transition around 70 K is remarkably broadened by about 2 K. The present results demonstrate that the Scotch tape is a simple and effective tool to probe structure sensitive physical properties of layered materials. [ABSTRACT FROM AUTHOR]

We investigated the superconducting transition temperature Tc of FeSe0.5Te0.5 single crystals, which can be enhanced up to 14% by attaching onto a commercial Scotch tape. The Scotch tape exhibits a large cooling shrinkage at low temperatures, which is considerably more pronounced than that of the metallic FeSe0.5Te0.5 single crystal, thus providing a compressive strain of 2.4 x 10-3 at 15 K. For such strain, we calculated that the lattice parameter of c/a can be increased to ~0.31%, which corresponds to the enhancement of the superconductivity. The present finding provides a rapid and simple method to examine the microstructure sensitive physical properties of the layered-structure materials by using the Scotch tape as strain generator. [ABSTRACT FROM AUTHOR]

In the superconductor of FeSe0.5Te0.5, the superconductivity is highly sensitive to variations of microstructure. Therefore, a fine manipulation of the microstructures will be crucial not only for a better understanding of the superconductivity but also for potential applications. Here, we demonstrate an approach to control the superconductivity in-situ by using a magnetostrictive substrate ZnCr2Se4 as the strain generator. By mounting an FeSe0.5Te0.5 single crystal onto a magnetostrictive substrate, we show that the magnetoresistance of FeSe0.5Te0.5 is directly coupled to the magnetostriction of ZnCr2Se4. The strain is fine-tuned in-situ by an external magnetic field, leading to the superconductivity of FeSe0.5Te0.5 correspondingly favored by compressive strain while suppressed by tensile strain. [ABSTRACT FROM AUTHOR]

We conducted in-situ high-pressure synchrotron x-ray diffraction (XRD) and electrical transport measurements on Dirac-like semimetal PdSn4 in diamond anvil cells with quasi-hydrostatic pressure condition up to 44.5 GPa–52.0 GPa. The XRD data show that the ambient orthorhombic phase (Ccca) is stable with pressures to 44.5 GPa, and the lattice parameters and unit-cell volume decrease monotonously upon compression. The temperature dependence of the resistance exhibits a metallic conduction and follows a Fermi-liquid behavior below 50 K, both of which keep unchanged upon compression to 52.0 GPa. The magnetoresistance curve at 5 K maintains a linear feature in a magnetic field range of 2.5 T–7 T with increasing pressure to 20.0 GPa. Our results may provide pressure-transport constraints on the robustness of the Dirac fermions. [ABSTRACT FROM AUTHOR]

The terahertz (THz) time domain spectroscopy (THz-TDS) of a ZnCr2Se4 single crystal has been performed under magnetic fields up to 9 Tesla at low temperatures. It was found that the magnetic resonance absorption originating from screw-spin-structure precession emerges in the THz region and evolves into ferromagnetic resonance absorption with the application of an external magnetic field. Benefiting from the phase- and polarization-sensitive detection technique of THz-TDS, the THz Faraday rotations of ZnCr2Se4 were observed in both time and frequency domains, whose temperature and magnetic field dependences manifest typical magnetic structure transitions. [ABSTRACT FROM AUTHOR]