Search

This work presents Bi 2 O 3 -doped SnO 2 ceramic varistors prepared through conventional ceramic processing in the sintering temperature range of 1290–1320°C. The sample sintered at 1300°C exhibits a breakdown electric field as low as 11.6 V mm - 1 . Scanning electron microscopy images reveal that all the samples have a compact structure, and energy dispersive spectroscopy results for the sample sintered at 1300°C indicate that Bi distributes homogeneously along the grain boundaries and aggregates inhomogeneously on the grain surfaces. With increasing sintering temperature, the grain boundary barrier height remains nearly constant at 0.80 eV. In both the dielectric loss and electric modulus spectra of the sample sintered at 1300°C, obvious relaxations were observed and the activation energies obtained from the respective spectra were 0.33 and 0.15 eV, which are expected to be related to oxygen vacancies and interstitial ions, respectively. Complex impedance spectra are employed to develop a non-typical equivalent circuit model for the Bi 2 O 3 -doped SnO 2 ceramic varistors at low voltage that yields an excellent fit to the data. [ABSTRACT FROM AUTHOR]

Malnutrition is a common complication in the dialysis population, both hemodialysis and peritoneal dialysis (PD). We report our exploratory study on the characteristics of intestinal microbiota and nutritional status in PD patients. The nutritional status of our PD patients were evaluated, and their feces were collected for 16S rRNA gene V3-V4 regions amplification and high-throughput sequencing. The characteristics and differences of microbiota between the well-nourished (W) and malnourished (M) groups were compared. We studied the genera and the operational taxonomic units (OTUs) within the genus of our patients, initially comparing the malnourished and the well- nourished groups and later on reanalyzing the whole group using these OTUs. At the OTU level, 6 bacteria were significantly correlated with the serum albumin level. The abundances of 2 OTUs (OTU208 Lachnospiraceae_incertae_sedi and OTU4 Bacteroides) were more in W group. Meanwhile, 4 OTUs (OTU225 Akkermansia, OTU87 Megasphaera, OTU31 Peptostreptococcaceae_incertae_sedi and OTU168 Clostridium_sensu_strictu) displayed higher abundance among individuals in M group. Notably, the OTU168 Clostridium_sensu_stricto was the only bacteria that significantly correlated with serum albumin (r = − 0.356, P = 0.05), pre-albumin (r = − 0.399, P = 0.02), and SGA (r = 0.458, P = 0.01). The higher the OTU168 Clostridium_sensu_strictu, the lower serum albumin and pre-albumin and a higher score of SGA signifying a worse nutritional status. Our preliminary findings suggested a relationship between the nutrition status and microbiota in PD patients. Our results provide a basis for further exploration of the interactions between malnutrition and intestinal flora in PD patients with potential interventions using probiotics and prebiotics. [ABSTRACT FROM AUTHOR]

Tetracycline (TC), as a typical micro-pollutant in natural environment, has attracted much attention. The peroxymonosulfate (PMS)-based advanced oxidation process is regarded as a promising technology for TC treatment, while its potential practical application is mainly dependent on the oxidant yield derived from activating PMS by catalysts. Therefore, the development of improved activators which are characterized by adequate activity and stability for PMS decomposition is in high demand. In this paper, the high-efficiency K2−xMn8O16 nanowire hydrogels (KNH) with high stability was synthesized through a simple hydrothermal method and then an enhanced PMS/KNH system for antibiotic degradation via multiple strategies was established. For removal of low-concentration TC, a high degradation of nearly 95% could be achieved by activating PMS in a wide pH rang. More than that, a further catalytic mechanism of this PMS/KNH system was also put forward, thus providing a guideline for designing and fabricating transition-metal catalysts to activate PMS. [ABSTRACT FROM AUTHOR]

Local energy extrema of the bands in momentum space, or valleys, can endow electrons in solids with pseudospin in addition to real spin. In transition metal dichalcogenides this valley pseudospin, like real spin, is associated with a magnetic moment that underlies the valley-dependent circular dichroism that allows optical generation of valley polarization, intervalley quantum coherence and the valley Hall effect. However, magnetic manipulation of valley pseudospin via this magnetic moment, analogous to what is possible with real spin, has not been shown before. Here we report observation of the valley Zeeman splitting and magnetic tuning of polarization and coherence of the excitonic valley pseudospin, by performing polarization-resolved magneto-photoluminescence on monolayer WSe2. Our measurements reveal both the atomic orbital and lattice contributions to the valley orbital magnetic moment; demonstrate the deviation of the band edges in the valleys from an exact massive Dirac fermion model; and reveal a striking difference between the magnetic responses of neutral and charged valley excitons that is explained by renormalization of the excitonic spectrum due to strong exchange interactions. [ABSTRACT FROM AUTHOR]