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  • Author: Qian Fan x
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Abstract

A basic study of melt spinning of polypropylene is reported. This study is aimed at developing a new technology for the manufacture of fine denier polypropylene fibers for clothing end uses. It was found that the molecular weight of the polypropylene resin has-a key influence on structure development in the fiber spinline. By aiming at achieving a smectic structure of the as-spun fiber through a controlled degradation of polypropylene, we can spin fine denier good quality polypropylene fibers at temperatures below 280°C and speeds up to 2000 meters/minute.

Abstract

Based on deeply analysis for optimization process of basic fruit fly optimization algorithm (FOA), a new improved FOA (IFOA) method is proposed, which modifies random search direction, increases the adjustment coefficient of search radius, and establishes a multi-sub-population solution mechanism. The proposed method can process the nonlinear objective function that has non-zero and non-negative extreme points. In the paper, IFOA method is applied to ill-conditioned problem solution in the field of surveying data processing. Application of the proposed method on two practical examples show that solution accuracy of IFOA is superior to that of three well-known intelligent optimization algorithms and two existing improved FOA methods, and it is also better than truncated singular value decomposition method and ridge estimation method. In addition, compared with intelligent search method represented by particle swarm optimization algorithm, The IFOA method has the advantages of less parameter settings, simple optimization process and easy program implementation. So, IFOA method is feasible, effective and practical in solving ill-conditioned problems.

Abstract

Background: The aim of the study was to investigate the incidence and genotype-phenotype characteristics of UDP-galactose-4′-epimerase (GALE) deficiency in newborn screening of Chinese population.

Methods: Neonates were screened at the Newborn Screening Center of Zhejiang Province, China for GALE deficiency and their condition was confirmed by testing of the GALE gene and GALE enzyme. Clinical and laboratory follow-up data were recorded.

Results: A total of 350,023 of newborns were screened; of which, the condition of one female neonate was diagnosed with GALE deficiency, accounting for an incidence rate of approximately 1:350,000 in our sample. The patient with GALE deficiency clinically manifested slight increase in levels of blood galactose (122–251 mg/L), glutamyl endopeptidase (61 U/L), total bile acid (17 μmol/L), and lactic acid (1.8 mmol/L). The neonate was fed with lactose-free powdered milk and followed-up to 1 year. Re-examination showed that all biochemical indicators recovered to normal range, whereas physical and mental development appeared normal without cataract change. The genotype of GALE deficiency was identified as compound heterozygous mutations: c.505C>T (p.R169W) and c.452G>A (p.G151D). The latter was a novel mutation. The GALE enzyme value was 42% of control.

Conclusions: GALE deficiency is relatively rare in China. The genotype of compound heterozygous mutations at R169W and G151D clinically manifest as mild-type; it is recommended to limit galactose diet.

Synthesis of unsymmetrical organic carbonates by transesterification of various alcohols with diethyl carbonate (DEC) is an interesting topic in green chemistry. In this work, we synthesized a kind of zirconium phosphonate functionalized with pendent N-SO3H group by the reaction of ZrOCl2·8H2O with N,N-bis(phosphonomethyl)-sulfamic acid, which was formed from sulfamic acid through a Mannich-type reaction. The functionalized zirconium phosphonate was characterized by Fourier transform/infrared (FT/IR), N2 adsorption and desorption, scanning electron microscopy (SEM), and powder X-ray diffraction (XRD) techniques, and was used as the heterogeneous catalyst for the synthesis of unsymmetrical organic carbonates by transesterification of various alcohols with DEC. It was demonstrated that the catalyst is very active and selective for the reactions, and very high yields of the desired products could be obtained. In addition, the catalyst could be easily recovered and the decrease in catalytic activity and selectivity was minor after three-fold usage. The mechanism for the transesterification reactions is discussed.

Abstract

A new complex [C(NH2)3]2[Mn(N3)4], in which MnII cations are alternatively bridged by double EE azide-bridges and the [Mn(N3)4]n 2− chains are separated by guanidinium cation bilayers, has been synthesized and characterized by single crystal X-ray diffraction, infrared (IR) spectroscopy, elemental analyses, and magnetic measurements. Magnetic susceptibility data indicate antiferromagnetic interaction among the MnII ions.

Abstract

A comparison of chestnut polysaccharide extraction using ultrasound-assisted extraction (UAE) and hot water extraction (HWE) demonstrated that UAE is superior to HWE due to its higher extraction efficiency. Scanning electron microscopy (SEM), thermogravimetric analysis-differential scanning calorimetry (TGA-DSC) and Fourier-transform infrared spectroscopy (FTIR) were used to characterize the ultrasound-assisted-extracted polysaccharide (UAEP) and hot water-extracted polysaccharide (HWEP). SEM images revealed that the UAEP and chestnut residue were crushed, with particle sizes that were smaller than those of the HWEP, which was related to the breakage of long-chain polysaccharides. TGA-DSC showed a higher transition temperature and enthalpy value for the UAEP than the HWEP, and the FTIR spectrum revealed typical characteristics of polysaccharides, with some differences between the UAEP and HWEP. The evaluation of antioxidant activities showed that the UAEP had stronger antioxidant capacities than the HWEP, regardless of the reducing power and DPPH-, ABTS- and hydroxyl radical-scavenging activities, suggesting that ultrasound is an optimal method to rapidly extract chestnut polysaccharide, a potential natural antioxidant.

Abstract

Objective

This study assessed the methodological quality of systematic reviews/meta-analysis of the effectiveness of probiotics against irritable bowel syndrome (IBS) using the accepted methodological quality assessment scale AMSTAR and explored the factors that influenced the quality of methodology. It was designed to provide a reference for future research and systematic reviews/metaanalysis.

Methods

The methodological quality of existing systematic reviews/meta-analysis was evaluated using the AMSTAR scale. Influencing factors of methodological quality were statistically analyzed using RevMan 5.3 software. The included systematic reviews/metaanalysis must include the following characteristics: (1) methods using systematic evaluation/meta-analysis, (2) probiotic intervention, and (3) language limitation to Chinese and English.

Results

The AMSTAR score was 5–9 (7.42 ± 1.22), and the quality is above average. The factors affecting the methodological quality are the number of authors and whether they cooperate with the institution.

Conclusions

Studies have shown that current systematic reviews/meta-analysis of the effectiveness of probiotics on IBS does not fully comply with methodological quality standards, and therefore the methodological quality of research in this area needs to be strengthened. To better clarify how probiotics affect IBS, future systematic reviews and meta-analyses should not only follow methodological quality standards but also include more effective outcome measures, and they should focus more on the discussion of research results. We look forward to the development of higher-quality randomized controlled trials in the future.

Abstract

Copper germanate (CuGeO3) nanowires have been synthesized by the hydrothermal deposition process using GeO2 and copper foil as the resource as well as the deposition substrate. The factors including hydrothermal temperature, pressure and duration of the process were investigated in order to analyze the processing parameters that control the formation process, morphology and size of the nanowires. The dependence of the nanowires properties on the growth conditions shows that the CuGeO3 nanowires can be synthesized in a large range of different hydrothermal parameters from 400 °C to 250 °C. The hydrothermal pressure has an important effect on the formation and growth of the CuGeO3 nanowires. The CuGeO3 nanowires exhibit good electrochemical cyclic voltammetry characteristics owing to offering many advantages in sensing applications including their small size, high aspect ratio and conductance.

Abstract

The liquid-liquid extraction behavior of short-lived molybdenum and tungsten isotopes from HCl and HNO3 as well as HF/HNO3 acid media was studied using the α-benzoinoxime/chloroform system. The goal of the present experiments was to find an extraction system with a high selectivity for the group 6 elements in the periodic table which is suitable for the study the solution chemistry of seaborgium (Z=106). It was found that Mo and W are both effectively extracted using α-benzoinoxime as an extractant and the maximum extraction yield is 100% and 94% for Mo and W, respectively. Ions of MO2 2+ (M=Mo, W) exist in HCl between the concentration range of 0.1−3 M and can be extracted quantitatively into the organic phase. The decrease of extraction yields at lower or higher acid concentration is due to the formation of anionic species MO4 2- or MO2Cl3 -. The extraction behavior of Mo and W in HNO3 solution is similar to that in HCl solution. In HNO3/HF mixed acid solutions, due to the formation of MO2F3 - a decrease of extraction yield at higher HF concentration, similar to the case of HCl is observed. The extraction equilibrium is reached within 10−30 s, which means the extraction kinetics of α-benzoinoxime/chloroform extraction system is fast enough for the study of the isotope 265Sg. The extraction behavior of molybdenum and tungsten shows a distinct difference in the range of 0.05 to 0.2 M HF with 1 M HNO3. This shows that differences in the complexation with fluoride ion exist in Mo and W. This study focuses on the investigation of the tendency of group 6 element for complexation with fluoride ion.