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Lithium–sulfur batteries (LSBs) are one of the main candidates for the next generation of energy storage systems. To improve the performance of LSBs, we herein propose the use of strained MoS2 (s-MoS2) as a catalytically active sulfur host. The introduction of strain in the MoS2 surface, which alters its atomic positions and expands the S–Mo–S angle, shifts the d-band center closer to the Fermi level and provides the surface with abundant and highly active catalytic sites; these enhance the catalyst's ability to adsorb lithium polysulfides (LiPS), accelerating its catalytic conversion and promoting lithium-ion transferability. Strain is generated through the synthesis of core–shell nanoparticles, using different metal sulfides as strain-inducing cores. s-MoS2 nanoparticles are supported on carbon nanofibers (CNF/s-MoS2), and the resulting electrodes are characterized by capacities of 1290 and 657 ​mAh g−1 ​at 0.2 and 5 ​C, respectively, with a 0.05% capacity decay rate per cycle at 8 ​C during 700 cycles. Overall, this work not only provides an ingenious and effective strategy to regulate LiPS adsorption and conversion through strain engineering, but also indicates a path toward the application of strain engineering in other energy storage and conversion fields.

Background: Amide proton transfer (APT) imaging has recently emerged as an important contrast mechanism for magnetic resonance imaging (MRI) in the field of molecular and cellular imaging. The aim of this study was to evaluate the feasibility of APT imaging to detect cerebral abnormality in patients with Alzheimer′s disease (AD) at 3.0 Tesla. Methods: Twenty AD patients (9 men and 11 women; age range, 67-83 years) and 20 age-matched normal controls (11 men and 9 women; age range, 63-82 years) underwent APT and traditional MRI examination on a 3.0 Tesla MRI system. The magnetic resonance ratio asymmetry (MTR asym ) values at 3.5 ppm of bilateral hippocampi (Hc), temporal white matter regions, occipital white matter regions, and cerebral peduncles were measured on oblique axial APT images. MTR asym (3.5 ppm) values of the cerebral structures between AD patients and control subjects were compared with independent samples t-test. Controlling for age, partial correlation analysis was used to investigate the associations between mini-mental state examination (MMSE) and the various MRI measures among AD patients. Results: Compared with normal controls, MTR asym (3.5 ppm) values of bilateral Hc were significantly increased in AD patients (right 1.24% ± 0.21% vs. 0.83% ± 0.19%, left 1.18% ± 0.18% vs. 0.80%± 0.17%, t = 3.039, 3.328, P = 0.004, 0.002, respectively). MTR asym (3.5 ppm) values of bilateral Hc were significantly negatively correlated with MMSE (right r = −0.559, P = 0.013; left r = −0.461, P = 0.047). Conclusions: Increased MTR asym (3.5 ppm) values of bilateral Hc in AD patients and its strong correlations with MMSE suggest that APT imaging could potentially provide imaging biomarkers for the noninvasive molecular diagnosis of AD.

The purpose of this work is to elucidate the selective area growth of SiC nanorods on the electrospun nanofibers catalyzed by terbium metals, and further explore the optimal growth conditions and field emission properties in this case. X-ray diffraction, Raman spectroscopy, field-emission scanning electron microscopy, and transmission electron microscopy were used to investigate the growth mechanism. Test results indicated that our experimental process should be an organic whole and each aspect is indispensable. Furthermore, our work finished up with excellent field emission results, showing a rather low Eto of 8 V/μm and a large β value of 904. [ABSTRACT FROM AUTHOR]

Well-crystallized β-SiC nanorods grown on electrospun nanofibers were synthesized by carbothermal reduction of Tb doped SiO2 (SiO2:Tb) nanofibers at 1,250 °C. The as-synthesized SiC nanorods were 100–300 nm in diameter and 2–3 μm in length. Scanning electron microscopy (SEM) results suggested that the growth of the SiC nanorods should be governed by vapor-liquid-solid (VLS) mechanism with Tb metal as catalyst. Tb(NO3)3 particles on the surface of the electrospun nanofibers were decomposed at 500 °C and later reduced to the formation of Tb nanoclusters at 1,200 °C, and finally the formation of a Si–C–Tb ally droplet will stimulate the VLS growth at 1,250 °C. Microstructure of the nanorod was further investigated by transmission electron microscopy (TEM). It was found that SiC <111> is the preferred initial growth direction. The liquid droplet was identified to be Si86Tb14, which acted as effective catalyst. Strong green emissions were observed from the SiC nanorod samples. Four characteristic photoluminescence (PL) peaks of Tb ions were also identified. [ABSTRACT FROM AUTHOR]

Aim: Retrospectively to analyze the risk factors of postoperative respiratory dysfunction (RD) in 196 patients with type A dissection operated on with cerebral perfusion and a lower body hypothermia circulatory arrest (HCA) and to investigate the method of the lung protection. Methods: From January 2005 to April 2008, 196 patients with type A dissection underwent surgical repair with cerebral perfusion and HCA. There were 142 male patients and 54 female patients, with ages from 17 to 78 years. Antegrade selective cerebral perfusion (SCP) through the axillary artery was performed for 168 patients and retrograde cerebral perfusion (RCP) from the superior vena cava for 28 patients. All the factors underwent univariate and multivariate analysis. Results: Mean cardiopulmonary bypass (CPB) duration was (186±56) minutes and mean cerebral perfusion time was (35±15) minutes; mean HCA time was (39±14) minutes. Postoperative RD was detected in 26 patients (13.3%). Multivariate analysis showed that the longer duration of circulatory arrest (CA), P=0.008, OR=1.048, and the higher temperature in the bladder during CA, P=0.002, OR=1.614, were independent risk factors of postoperative RD. There was a higher mortality (23.1%, P=0.025) in patients with postoperative RD when compared with the other patients. Conclusion: The longer duration of CA and the higher temperature in the bladder during CA were found to be the independent risk factors of postoperative RD after type A aortic dissection surgery. Attention should be paid to lung protection for these patients and the adjunct of continuing descending aortic perfusion and cerebral perfusion should be a safe and feasible procedure and it would be valuable to perform a prospective trial. [ABSTRACT FROM AUTHOR]

It is demonstrated that the incorporation of graphene materials into oxide-based photoanodes can greatly increase the photoelectrochemical devices’ performances. In this work, reduced graphene oxide (rGO) has been incorporated into P25-TiO2 nanoparticle (NP) based photoanodes for fiber-shaped dye-sensitized solar cells (FDSSCs). Results showed that the rGO nanosheets have been uniformly dispersed within P25 nanoparticle layers, and, as expected, the incorporation of rGO increased the FDSSCs’ short current density from 8.344 to 12.935 mA cm−2, open circuit voltage from 0.775 to 0.798 V, resulting into their power conversion efficiency (PCE) from 3.940% to 5.364%. This large increasement in PCE could be due to two aspects, i.e. the improved electron transport properties via rGO and the enhanced separation of photogenerated hole–electron pairs via rGO-TiO2 heterojunction. Furthermore, the incorporation of rGO can also make the FDSSCs have good mechanical properties, which is very crucial for their future applications in smart wearable electronics. In addition, based on our analysis, a possible rGO/multi-NP coupling enhancement mechanism was proposed. [ABSTRACT FROM AUTHOR]