1+1大于2 4～7层安全应用进行时

1 立足渠道构建 Radware与神州数码在2002年末建立了战略合作伙伴关系,在2003～2006年3年间,通过双方共同的努力,从2005年下半年开始,合作走上正轨.在多年的合作历程中,磨合和成长中积累的经验,成为他们共同的财富.也正是因为在合作中这样那样的困难和问题,使双方的信任度不断加深.     

在化学实验课中运用剖析-比较-发散实验教学法的探讨

分析了几种化学课的教学目的和特点,提出并论述了剖析-比较-发散实验教学法的具体内容和实施步骤,并对研究探讨这种教学法的必要性作了说明。     

糠醛氧化合成糠酸

糠酸作为糠醛的重要下游产品,在食品制造、材料制备、光学技术、药物合成中具有重要的应用,可用于合成防腐剂、增塑剂、热固性树脂、香料以及多种药物。目前,关于糠醛的制备以及催化氢化制备下游产物的综述报道相对较多,但是还没有系统地整理评述糠醛氧化合成糠酸的相关工作。本文综述了近年来以糠醛为主要原料制备糠酸的研究进展情况,讨论了不同催化体系及在不同氧源存在下对糠酸选择性的影响,重点突出了非均相催化剂在糠酸的工业化制备中的应用前景,对糠酸制备的未来发展方向进行了展望。     

Rosmanol and Carnosol Synergistically Alleviate Rheumatoid Arthritis through Inhibiting TLR4/NF-κB/MAPK Pathway

Callicarpalongissima has been used as a Yao folk medicine to treat arthritis for years in China, although its active anti-arthritic moieties have not been clarified so far. In this study, two natural phenolic diterpenoids with anti-rheumatoid arthritis (RA) effects, rosmanol and carnosol, isolated from the medicinal plant were reported on for the first time. In type II collagen-induced arthritis DBA/1 mice, both rosmanol (40 mg/kg/d) and carnosol (40 mg/kg/d) alone alleviated the RA symptoms, such as swelling, redness, and synovitis; decreased the arthritis index score; and downregulated the serum pro-inflammatory cytokine levels of interleukin 6 (IL-6), monocyte chemotactic protein 1 (MCP-1), and tumor necrosis factor α (TNF-α). Additionally, they blocked the activation of the Toll-like receptor 4 (TLR4)/nuclear factor κB (NF-κB)/c-Jun N-terminal kinase (JNK) and p38 mitogen-activated protein kinase (MAPK) pathways. Of particular interest was that when they were used in combination (20 mg/kg/d each), the anti-RA effect and inhibitory activity on the TLR4/NF-κB/MAPK pathway were significantly enhanced. The results demonstrated that rosmanol and carnosol synergistically alleviated RA by inhibiting inflammation through regulating the TLR4/NF-κB/MAPK pathway, meaning they have the potential to be developed into novel, safe natural combinations for the treatment of RA.     

Bioactive PKS–NRPS Alkaloids from the Plant-Derived Endophytic Fungus Xylaria arbuscula

A novel hybrid PKS–NRPS alkaloid, xylarialoid A (1), containing a 13-membered macrocyclic moiety and [5,5,6] fused tricarbocyclic rings, together with ten known cytochalasins (2–11), was isolated from a plant-derived endophytic fungus, Xylaria arbuscula. The chemical structures of all compounds were elucidated using 1D and 2D NMR, HR ESIMS spectroscopic analyses, and electronic circular dichroism (ECD) calculation. Compounds 1–3 and 10 exhibited significant antitumor activities against A549 and Hep G2 cell lines, with IC₅₀ values of 3.6–19.6 μM. In addition, compound 1 showed potent anti-inflammatory activity against LPS-induced nitric oxide (NO) production in macrophage RAW 264.7 cells (IC₅₀, 6.6 μM).     

Chitosan and Whey Protein Bio-Inks for 3D and 4D Printing Applications with Particular Focus on Food Industry

The application of chitosan (CS) and whey protein (WP) alone or in combination in 3D/4D printing has been well considered in previous studies. Although several excellent reviews on additive manufacturing discussed the properties and biomedical applications of CS and WP, there is a lack of a systemic review about CS and WP bio-inks for 3D/4D printing applications. Easily modified bio-ink with optimal printability is a key for additive manufacturing. CS, WP, and WP–CS complex hydrogel possess great potential in making bio-ink that can be broadly used for future 3D/4D printing, because CS is a functional polysaccharide with good biodegradability, biocompatibility, non-immunogenicity, and non-carcinogenicity, while CS–WP complex hydrogel has better printability and drug-delivery effectivity than WP hydrogel. The review summarizes the current advances of bio-ink preparation employing CS and/or WP to satisfy the requirements of 3D/4D printing and post-treatment of materials. The applications of CS/WP bio-ink mainly focus on 3D food printing with a few applications in cosmetics. The review also highlights the trends of CS/WP bio-inks as potential candidates in 4D printing. Some promising strategies for developing novel bio-inks based on CS and/or WP are introduced, aiming to provide new insights into the value-added development and commercial CS and WP utilization.     

A Mechanism of High-Tc Superconductivity Relating to Perovskite Crystal Structure

A mechanism of high-T_c superconductivity related to the perovskite crystal structure is proposed by a “phonon attenuation model”, which means that in the perovskite-like crystal structure, a number of “ordering” vacancies or holes occur due to the non-stoichiometric structure features. Such a reticular “spongly-like” structure facilitates lattice thermovibration attenuation perovskite (phonon attenuation) during temperature reduction. This leads to an abrupt drop of the resistivity, owing to the conduction electrons transmitted through the media without collision with irregularities in the lattice due to the lattice thermovibration. This probably is the main reason for high-T_c superconductivity of the perovskite cuprates.     

宽频带激光自由空间传输的调制特性研究

基于惠更斯-菲涅耳衍射积分公式,研究了宽带光束在菲涅耳衍射区的自由空间传输特性,得到宽带光束传输的调制深度与光束带宽Δλ及菲涅耳数F的变化关系。结果表明:一定的带宽对光束的均匀性有适当的改善;当光束的带宽Δλ<2λ0/F时,带宽越大,光束越均匀;当带宽满足条件Δλ=2λ0/F时,菲涅耳衍射完全消失;在一定的菲涅耳数范围内,宽带光束的调制深度随菲涅耳数振荡变化,振荡曲线的主极大值和次极大值分别出现在菲涅耳数为奇数和偶数处,而极小值则出现在菲涅耳数F=2k±1/3(k=1,2,3,…)处,在极小值处光束的均匀性最好。     

交互作用Fock空间l2(Γ,{λn})上的梯度算子和散度算子

主要研究基于l2(N)上交互作用Fock空间l2(Γ,{λn})中的梯度算子和散度算子.首先定义交互作用Fock空间l2(Γ,{λn})上的梯度算子和散度算子;然后研究梯度、散度算子所具有的算子性质;最后研究由梯度算子和散度算子构成的复合算子与该空间中其他算子的关系.结果表明:交互作用Fock空间l2(Γ,{λn})中...     

荧光分析法测定维生素C

维生素C经Cu2 氧化为脱氢抗坏血酸,与苯甲酸及十六烷基三甲基溴化铵产生荧光协同增敏作用。提出一种新的测定维生素C的高灵敏荧光分析法,建立了测定维生素C的适合条件。该方法的的线性范围为0.02~8.0μg/mL,检出限为0.006 5μg/mL。对3.0μg/mL的维生素C测定6次,测定结果的相对标准偏差为0.12%。将该法用于西红柿、果珍以及维生素C药片中维生素C含量的测定,加标回收率为96.7%~100.5%。