肌醇代谢关键基因与神经管畸形关系的研究进展

神经管畸形(neural tube defect,NTD)是一种复杂的、严重的中枢神经系统出生缺陷,由遗传与环境因素共同影响.母体营养物质是NTD病因中一个重要的环境因素,包括维生素B族物质、叶酸及胆碱等.肌醇作为一种维生素B族物质,与胚胎发育及NTD发生密切相关.研究发现,肌醇补充可预防叶酸抵抗型NTD,且其代谢通路关键基因在NTD发生过程中起着重要的作用.该文就肌醇代谢通路及其关键基因与NTD发生的关系进行综述,以期为NTD发病机制的深入研究及防治提供参考.     

High-strength lignin-based carbon fibers via a low-energy method

Bio-renewable carbon fibers are fabricated and employed as high-strength composite materials in many fields. In this work, a facile and low energy consumption method was developed to fabricate high-strength lignin-based carbon fibers. Using iodine treatment, the thermodynamic stability of the lignin-based precursor fibers increased significantly, and thus energy consumption during the preparation of the carbon fibers was reduced. The influence of the iodine treatment on fibers was analyzed by differential scanning calorimetry (DSC), scanning electron microscopy (SEM), Raman spectroscopy, tension testing, etc. The resulting iodine lignin-based carbon fibers had better tensile strength (89 MPa) than that of PAN carbon fibers produced by electrospinning technology.

A simple low-energy method to fabricate lignin-based carbon fibers with excellent mechanical properties via electrostatic spinning.     

A non-linear flow model for the flow behavior of water inrush induced by the karst collapse column

Water inrush induced by the karst collapse column (KCC) is a great threat to coal mine safety. In this study, a non-linear flow model that couples three flow types is built based on flow transition from laminar flow in the aquifer to turbulent flow in the mine roadways during the process of water inrush induced by KCC. The proposed model couples Darcy flow, Forchheimer flow, and turbulent flow, and is then used to simulate the flow behavior of water inrush induced by KCC. In particular, the “3.1” water inrush incident from the coal seam floor in the Luotuoshan coal mine, China, is numerically investigated. The numerical results show that with the increase of the inrush flow rate, Forchheimer flow in the water inrush channel is first controlled by viscous resistance, then affected by both viscous resistance and inertial resistance, and finally controlled by inertial resistance. Therefore, water inrush induced by KCC is a dynamic process with a transition from laminar to turbulent. The Forchheimer equation proved to be applicable in describing the high-velocity non-linear flow, and can also reflect the intermediate state of the flow translation from laminar flow in the aquifer to turbulent flow in the roadway during the water inrush process.

A non-linear flow model that couples three flow types is built based on flow transition to investigate the flow behavior of water inrush induced by KCC.     

Corrosion behavior of 904L austenitic stainless steel in hydrofluoric acid

Corrosion behaviors of 904L austenitic stainless steel in HF and HCl were studied and compared using electrochemical method, microscopic analysis, and phase analysis. An insoluble layer is deposited on 904L in HF due to a preferential reaction between [F⁻] and the [Ni] from the alloy. This insoluble deposited layer not only helps isolate the aggressive ions from the base metal, but also inhibits the passivation of 904L in HF, the mechanism for which was entirely different from that in HCl.

An insoluble layer is deposited on 904L in HF due to a preferential reaction between [F⁻] and the [Ni] from the alloy. This insoluble deposit layer helps isolate the aggressive ions from the base metal, while inhibits the passivation of 904L in HF.     

High voltage,solvent-free solid polymer electrolyte based on a star-comb PDLLA–PEG copolymer for lithium ion batteries

In this work, a novel star-comb copolymer based on poly(d,l-lactide) (PDLLA) macromonomer and poly(ethylene glycol)methyl ether methacrylate (PEGMA) was prepared, and the electrochemical properties were studied, with the aim of using it as a solid polymer electrolyte in lithium ion batteries. The six-arm vinyl functionalized PDLLA macromonomer was synthesized by a ring-opening polymerization (ROP) of d,l-lactide and subsequently an acylation of the hydroxy end-groups. A series of free-standing solid polymer electrolyte membranes from different ratios of PDLLA, PEGMA and LiTFSI were prepared through solvent-free free radical polymerization under UV radiation. The chemical structure of the obtained polymers was confirmed by ¹H NMR and FTIR. The as-prepared six-arm star-comb solid polymer electrolytes (PDLLA-SPEs) exhibit good thermal stability with T_d^5%s of ∼270 °C and low T_gs of −48 to −34 °C. The electrochemical characterization shows that the PDLLA-SPEs possess a wide electrochemical window up to 5.1 V with an optimal ionic conductivity of 9.7 × 10⁻⁵ S cm⁻¹ at 60 °C at an EO/Li⁺ ratio of 16 : 1. Furthermore, the all-solid-state LiFePO₄/Li cells display extraordinary cycling and rate performances at 60 °C by curing the PDLLA-SPEs directly on the cathode. These superior properties of the six-arm star-comb PDLLA-SPE make it a promising candidate solid electrolyte for lithium batteries.

In this work, a novel star-comb copolymer based on PDLLA macromonomer and PEGMA was prepared, and the electrochemical properties were studied, with the aim of using it as a solid polymer electrolyte in lithium ion batteries.     

Simultaneous voltammetric detection of dopamine,ascorbic acid and uric acid using a poly(2-(N-morpholine)ethane sulfonic acid)/RGO modified electrode

A poly(2-(N-morpholine) ethane sulfonic acid)/reduced graphene oxide (RGO) modified glassy carbon electrode (GCE) was prepared using an electropolymerization method, and was characterized by scanning electron microscopy (SEM) and electrochemical impedance spectroscopy (EIS). The electrochemical behaviors and simultaneous detection of ascorbic acid (AA), dopamine (DA) and uric acid (UA) at this electrode were studied by cyclic voltammetry (CV) and differential pulse voltammetry (DPV). Tests showed that this electrode exhibited excellent electrocatalytic activity towards the oxidation of AA, DA and UA. The oxidation peak currents of AA, DA and UA were proportional with their concentrations in the ranges 1.0 μM–30 μM (30 μM–100 μM), 0.05 μM–100 μM and 0.1 μM–100 μM, with detection limits of 0.43 μM, 0.0062 μM and 0.056 μM, respectively. In addition, this electrode exhibited an excellent selectivity, reproducibility and stability, and has been successfully used to determine real samples with satisfactory results.

A sensitive electrochemical sensor for simultaneously detecting dopamine, ascorbic acid and uric acid.     

Typical pharmaceutical molecule removal behavior from water by positively and negatively charged composite hollow fiber nanofiltration membranes

The rejection behaviors of two different charged composite hollow fiber nanofiltration (NF) membranes for six pharmaceutical molecules, primidone, carbamazepine, sulfamethoxazole, atenolol, sulfadimidine and norfloxacin, were characterized in this study. The saturation adsorption behaviors of the different pharmaceutical molecules on each membrane surface were studied and found to be related to the molecular weight, charge and hydrophilicity of the pharmaceutical molecules. After the pharmaceutical molecules reached adsorption equilibrium, the rejection rates of different NF membranes were characterized. The rejection rates of primidone, carbamazepine, sulfamethoxazole, atenolol, sulfadimidine and norfloxacin by the PEI-NF membrane were 85.6%, 91.8%, 79.9%, 98.1%, 93.3%, and 97.1%, respectively. Meanwhile, the rejection rates of the pharmaceutical molecules by the PIP-NF membrane were 82.2%, 85.4%, 91.5%, 79.1%, 87% and 93.3%, respectively. The influence of feed concentration, operation pressure, temperature, pH and ionic strength on the rejection behaviors of the different charged NF membranes were also studied.

The rejection behaviors of two different charged composite hollow fiber nanofiltration (NF) membranes for six pharmaceutical molecules, primidone, carbamazepine, sulfamethoxazole, atenolol, sulfadimidine and norfloxacin, were characterized in this study.     

Synthesis,electronic structures,and photoluminescence properties of an efficient and thermally stable red-emitting phosphor Ca3ZrSi2O9:Eu3+,Bi3+ for deep UV-LEDs

A series of red-emitting Ca₃ZrSi₂O₉:Eu³⁺,xBi³⁺ phosphors was synthesized using a conventional high temperature solid-state reaction method, for the purpose of promoting the emission efficiency of Eu³⁺ in a Ca₃ZrSi₂O₉ host. The site preference of Bi³⁺ and Eu³⁺ in the Ca₃ZrSi₂O₉ host was evaluated by formation energy. The effects of Bi³⁺ on electronic structure, luminescent properties, and related mechanisms were investigated. The inner quantum yield of the optimized sample increased to 72.9% (x = 0.08) from 34.6% (x = 0) at 300 nm ultraviolet light excitation. The optimized sample (x = 0.08) also showed excellent thermal stability, and typically, 84.2% of the initial emission intensity was maintained when the temperature increased to 150 °C from 25 °C, which is much higher than that without Bi³⁺ doping (70.1%). The mechanisms of emission properties and thermal stability enhancement, as well as the redshift of the charge transfer band (CTB) induced by Bi³⁺ doping in the Ca₃ZrSi₂O₉:Eu³⁺ phosphor, were discussed. This study elucidates the photoluminescence properties of Bi³⁺-doped Ca₃ZrSi₂O₉:Eu³⁺ phosphor, and indicates that it is a promising luminescent material that can be used in ultraviolet light-emitting diodes.

A red-emitting phosphor Ca₃ZrSi₂O₉:Eu³⁺,Bi³⁺ with high quantum yield and thermal stability was developed by introducing Bi³⁺ as an efficient sensitizer.     

Enhanced hydrogen evolution reaction activity of hydrogen-annealed vertical MoS2 nanosheets

Molybdenum disulfide (MoS₂) is a promising electrocatalyst for hydrogen evolution reaction (HER), but only edges and S-vacancies are catalytic active sites for the HER. Therefore, it is crucial to increase edge sites and S-vacancies for enhancing the HER activity of MoS₂. Here, we report an enhanced HER activity of MoS₂ by combing vertical nanosheets and H₂ annealing. Compared to horizontal MoS₂ nanosheets, pristine vertical MoS₂ nanosheets showed better HER activity due to a larger amount of edges. H₂ annealing further enhanced the HER activity of vertical MoS₂ nanosheets remarkably. Scanning electron microscopy (SEM), X-ray photoelectron spectra (XPS) and electrochemical impedance spectroscopy (EIS) were used to elucidate the enhanced HER activity by H₂ annealing. SEM images showed that H₂ annealing roughened the MoS₂ edges, leading to more edge sites. XPS data revealed the smaller S : Mo ratio after H₂ annealing, meaning more S-vacancies. Meanwhile, EIS measurements showed that charge transfer was accelerated by H₂ annealing. These findings elaborated the H₂ annealing induced enhancement of the HER activity, which were further confirmed by the subsequent re-sulfurization experiment.

Vertical configuration and H₂ annealing enhanced the hydrogen evolution reaction activity of MoS₂ nanosheets.