Assessment of the quantitative accuracy of Rietveld/XRD analysis of crystalline and amorphous phases in fly ash

An internal standard method based on Rietveld/XRD whole-pattern fitting analysis of fly ash is used to assess the quantitative accuracy to determine its crystalline and amorphous phases under various conditions such as internal standards (types, SiO2 or Al2O3 and dosages, 10–50%), incident X-rays (laboratory or synchrotron) and refinement software (GSAS or TOPAS). The results reveal that the quantitative stability is quite sensible to minor phases, identical to the internal standard, in fly ash. Errors positively correlate with the weight fraction of that minor phase and negatively correlate with the dosage of an internal standard and amorphous phase content in fly ash. The original equation for the amorphous phase calculation is not applicable for a case with a higher inherent quartz content (>2.5%) in fly ash while the dosages of the internal standard is lower than 20%. The original equation is modified as proposed. Based on it, the quantitative results of five different patterns report a good reproducibility with the arithmetic mean errors and the standard errors of identified main phases of around 1%.The access to the beamline BL14B1 facilities at the SSRF is appreciated and the support of SSRF management, User Office and beamline staff is highly appreciated. This Research is supported by the National Natural Science Foundation of China (No. 51602126), the National Key Research and Development Plan of China (2016YFB0303505) and the Program for Scientic Research Innovation Team in Colleges and Universities of Shandong Province

Effects of Antibacterial Peptide Extracted from Bacillus subtilis fmbJ on the Growth, Physiological Response and Disease Resistance of Megalobrama amblycephala

The effects of an antibacterial peptide obtained from Bacillus subtilis fmbJ on growth, serum lysozyme complements 3 and 4, total protein content, aspartate aminotransferase (AST), alanine aminotransferase (ALT), total antioxidative capacity, superoxide dismutase (SOD) activity, malondialdehyde (MDA) content, and disease resistance of Wuchang bream (Megalobrama amblycephala) were examined. Fish were randomly divided into five groups: a control group which was fed a basic diet, and four groups fed the basic diet supplemented with 0.1%, 0.2%, 0.4%, or 0.8% antibacterial peptide. At eight weeks, M. amblycephala fed the diet containing 0.2% antibacterial peptide had higher serum lysozyme activity, complement 3 and 4 contents, and SOD activity than the control fish, but lower serum MDA content and AST activity. Fish fed the 0.4% diet had higher weight gain rate, serum lysozyme activity, complement 4 content, total antioxidative capacity, and total protein than the control, and lower serum ALT activity. Feed conversion ratios of fish fed the 0.2% or 0.4% diets were lower than those of control fish. Artificial infection with Aeromonas hydrophila resulted in 93% cumulative mortality in the control group, and 61-84% in the groups fed the 0.2% or 0.4% diets. The present study suggests that feed supplementation with 0.2-0.4% antibacterial peptides can stimulate immunity, increase resistance to pathogenic infection, and promote growth in M. amblycephala

Progress in Understanding the Mechanism by Which Probiotics Alletivate Hyperuricemia

Hyperuricemia (HUA) is a disease caused by excessive production and/or inadequate excretion of uric acid (UA) in the body, and persistent HUA can lead to gout. Asymptomatic HUA is closely related to other metabolic diseases, such as chronic kidney disease, diabetes and cardiovascular disease. Probiotic intervention is a potentially safe, cost-effective treatment to improve HUA. This paper mainly describes the mechanisms of action of probiotics in reducing the level of uric acid, including inhibiting xanthine oxidase activity, absorbing and degrading purines in the intestine, regulating intestinal flora homeostasis and restoring intestinal barrier function. In addition, probiotics can promote uric acid excretion and consequently reduced uric acid levels by promoting the expression of urate transport proteins and inhibiting the expression of urate reabsorbing proteins. Probiotics have great potential in alleviating HUA. This review hopes to provide a theoretical basis for subsequent research

Reduced Graphene-Oxide Transducers for Biosensing Applications Beyond the Debye-Screening Limit

In the field of label-free biosensing, various transducer materials and strategies are under investigation to overcome the Debye-screening limitation of charged biomolecules. We demonstrate an in-line, impedimetric aptasensor with reduced graphene-oxide (rGO) thin films as transducers to detect prostate specific antigens (PSA) in a physiological buffer solution. Unlike classical electrochemical impedance spectroscopy (EIS), this direct, label-free and fully-electronic biosensor approach does not need any redox markers. As specific capture molecules, short anti-PSA aptamers ensured a close binding of the target molecules to the transducer surfaces. Results showed a limit of detection smaller than 33 pM of PSA and a wide detection range from 0.033 to 330 nM fully covering the clinically relevant range of PSA (0.115–0.290 nM). This promising performance can be attributed to the bipolar electronic transport characteristics of the ultra-thin rGO layers similar to pristine graphene. The attachment of target biomolecules to the films changes the resistance of the rGO thin films. Such an in-line EIS configuration with rGO thin films opens promising prospects for biosensing beyond the Debye-screening limitation, which is a major challenge for conventional semiconductor field-effect devices towards clinical applications.</p

Superconductivity of powder-in-tube Sr0.6K0.4Fe2As2 wires

Nb-sheathed Sr0.6K0.4Fe2As2 superconducting wires have been fabricated using the powder-in-tube (PIT) method for the first time and the superconducting properties of the wires have been investigated. The transition temperature (Tc) of the Sr0.6K0.4Fe2As2 wires is confirmed to be as high as 35.3 K. Most importantly, Sr0.6K0.4Fe2As2 wires exhibit a very weak Jc-field dependence behavior even the temperature is very close to Tc. The upper critical field Hc2(0) value can exceed 140 T, surpassing those of MgB2 and all the low temperature superconductors. Such high Hc2 and superior Jc-field performance make the 122 phase SrKFeAs wire conductors a powerful competitor potentially useful in very high field applications.Comment: 15 pages, 6 figure

Micro/Nanostructures and Mechanical Properties of Trabecular Bone in Ovariectomized Rats

Bone mechanical properties encompass both geometric and material factors, while the effects of estrogen deficiency on the material and structural characteristics of bone at micro- to nanoscales are still obscure. We performed a series of combined methodological experiments, including nanoindentation assessment of intrinsic material properties, atomic force microscopy (AFM) characterization of trabecular (Tb) nanostructure, and Tb microarchitecture and 2D BMD. At 15 weeks after surgery, we found significantly less Tb bone mineral density (BMD) at organ (−27%) and at tissue level (−12%), Tb bone volume fraction (−29%), Tb thickness (−14%), and Tb number (−17%) in ovariectomy (OVX) rats than in sham operated (SHAM) rats, while the structure model index (+91%) and Tb separation (+19%) became significantly greater. AFM images showed lower roughness Tb surfaces with loosely packed large nodular structures and less compacted interfibrillar space in OVX than in SHAM. However, no statistically significant changes were in the Tb intrinsic material properties—nanoindentation hardness, elastic modulus, and plastic deformation—nanoindentation depths, and residual areas. Therefore, estrogen deprivation results in a dramatic deterioration in Tb micro/nanoarchitectures, 3D volumetric BMD at both organ and tissue levels, and 2D BMD, but not in the nanomechanical properties of the trabeculae per se