粉葛与葛根多糖对脂多糖诱导RAW264.7细胞的抗炎作用

该研究通过脂多糖诱导RAW264.7细胞炎症模型,对粉葛粗多糖（FGC）、葛根粗多糖（GGC）以及粉葛均一多糖（FGJ）的抗炎作用进行比较。用CCK8试剂盒检测FGC、GGC以及FGJ对细胞活力的影响;相关试剂盒检测细胞产生NO、TNF-α、IL-6的分泌情况;蛋白印迹法检测NF-κB、Nrf2/HO-1通路相关蛋白表达,QPCR检测TNF-α、IL-6的mRNA表达,通过流式检测活性氧的产生。结果显示,在浓度为10、20、40 μg/mL时,FGC、GGC以及FGJ对细胞均没有毒性（p>0.05）。各浓度的FGC、FGJ不能抑制LPS诱导产生的的NO、TNF-α、IL-6（p>0.05）,GGC在浓度为40 μg/mL时,对NO、TNF-α、IL-6的抑制率达到38.46%、52.90%、55.87%,可以抑制细胞内ROS释放,在10、20、40 μg/mL时抑制率达到37.28%、41.05%、54.09%,在浓度为40 μg/mL时,对iNOS、COX-2、p-p65、p-IκBα的抑制率达到29.27%、95.04%、27.18%、28.45%,对Nrf2、HO-1蛋白的表达有促进作用,在浓度40 μg/mL时显著地抑制IL-6与TNF-α的mRNA表达,抑制率达到57.70%、81.68%。结果证明,GGC与FGC、FGJ相比抗炎活性更加明显,并且其抗炎作用是通过NF-κB与Nrf2/HO-1两条通路来实现的。     

Changes in the content and antioxidative activity of β-carotene and its metabolite vitamin A during gastrointestinal digestion and absorption and optimisation of HPLC-based detection

The β-Carotene (BC), an important precursor of vitamin A (VA), possesses antioxidant activity but is fat-soluble and has low bioavailability. In previous in-vitro assays evaluating antioxidant and 2,2′-azobis(2-amidinopropane) dihydrochloride (AAPH) free radical scavenging, both BC and VA showed a strong ability to scavenge radicals and protected cells from oxidative stress. Here, we used artificially simulated gastrointestinal digestion and Caco-2 cell absorption models to evaluate the bioavailability of the BC during gastrointestinal digestion and absorption using high-performance liquid chromatography (HPLC) analysis. We observed high absorptive and transfer rates of BC and detected retinol metabolites (Vitamin A). Therefore, BC can be detected in the acidic gastrointestinal environment using HPLC. Optimised method provided better separation of BC and VA in the column, improving the accuracy of the test results.     

Start-up, microbial community analysis and formation of aerobic granules in a tert-butyl alcohol degrading sequencing batch reactor

We demonstrate that compact well-settling aerobic granules can be developed in a sequencing batch reactor (SBR) for the biological removal of tert-butyl alcohol (TBA) using a strategy involving step increases in TBA loading rate achieved through increasing TBA concentrations in the influent. A moderate selection pressure that included a cycle time of 24 h and a start-of-cycle TBA concentration of 100 mg/L was initially introduced to encourage the growth and retention of biomass and avoid biomass loss from hydraulic washout. Start-of-cycle TBA concentrations were increased to 150, 300, 450, and 600 mg/L on days 90, 100, 121, and 199, respectively. These increases were only introduced after complete TBA removal was accompanied by visible improvements in biomass concentration and biomass settling ability. This acclimation strategy produced incrementally higher biomass concentrations and better settling biomass with higher specific TBA biodegradation rates. Effluent TBA concentrations were consistently below the detection limit of 25 microg/L. Aerobic granules were first observed about 180 days after reactor start-up. The granules had a clearly defined shape and appearance, settled significantly faster than the suspended sludge in the reactor, and eventually became the dominant form of biomass in the reactor. The adapted granules were capable of complete TBA removal and contained a stable microbial population with a low diversity of sequences of community 16S rRNA gene fragments. This study indicates that it is possible to use aerobic granules for TBA remediation and will contribute to a better understanding of how microbial acclimation can be exploited in the SBR to biologically remove recalcitrant xenobiotics.     

双乙酸钠对鲜湿米粉条保鲜和品质的影响

研究山梨酸钾、脱氢乙酸钠、双乙酸钠以及丙酸钙对鲜湿米粉条的保鲜效果,结果显示,双乙酸钠保鲜效果最优,添加量为0.2g/kg,残留量未检出。探讨了双乙酸钠对鲜湿米粉条感官要求、理化指标及微生物指标的影响,结果表明,添加双乙酸钠后,显著降低了霉菌总数,鲜湿米粉条外观、色泽、气味、口味等感官要求均有明显改善,水分、酸度等理化指标变化很小。     

北美特种纸行业概况

从市场总量、产品分类、生产设备以及行业现状等方面,概括分析了北美地区特种纸行业的整体状况。北美地区58家特种纸公司每年产量总计约为300万t,其中5大特种纸公司各自所占市场份额均超过7%,排名前12位的公司总计占市场份额总量的69%。北美地区特种纸机平均产能居全球第一,但平均技术年龄也最高。造成这一局面的原因在于北美地区特种纸行业发展成熟、市场饱和,近年来对本行业的新投资远落后于全球其他地区。随着各种新技术、新材料的诞生以及对环保、可再生能源等领域的重视,北美特种纸行业将迎来新的发展机遇。     

高压比增压器高原适应性改进配机试验研究

利用进排气系统高原状态模拟试验台架,针对所研制的增压比为4.4的高压比增压器开展高原适应性改进配机试验研究。对原型增压器,减小涡轮箱,更换高压比压气机共3组试验数据进行了详细分析。     

典型曝气增氧技术及其案例分析

曝气增氧技术通过人工辅助措施增强水体复氧,提升污染水体溶解氧含量,激活水体好氧生物活性,具有处理效果好、投资低、见效快等优势,已广泛应用于河湖水环境治理工程中.通过对几种典型曝气增氧技术特点对比和案例分析,为曝气增氧工程方案设计提供参考和借鉴.     

Waste sugar solution polymer-derived N-doped carbon spheres with an ultrahigh specific surface area for superior performance supercapacitors

Waste sugar solution (WSS), a waste by-product of manufacturing vitamin C, contains abundant waste acids and organics. In this work, a N/O-enriched copolymer was synthesized via a facile polymerization via the hydrogen bonding of O-containing functional groups and melamine and the crosslinking of aldehyde groups. Subsequently, N-doped carbon spheres were prepared by a typical carbonation/activation method. Remarkably, benefiting from an ultrahigh specific surface area (3612 m²/g) and rich heteroatom content (4.3% for N, 8.8% for O), the carbon spheres deliver a high specific capacitance of 387 F/g at 50 mA/g and 283 F/g at 5 A/g with 6 M KOH in two-electrode system. The assembled symmetric electric double-layer capacitor exhibits high energy density of 10.83 Wh/kg at 11.10 W/kg. This research provides a facile method for preparing N/O-doped carbon spheres by WSS, and confirms the excellent electrochemical performance of WSS-derived carbons in energy storage applications.     

汽油/乙醇双燃料复合喷射对发动机排放性能的影响

通过在一台汽油气道喷射(GPI)的单缸、四冲程发动机上增加一套乙醇缸内直喷(EDI)系统,将其改装成为双喷射发动机,研究了汽油/乙醇复合喷射对发动机排放性能的影响,并建立了发动机计算流体动力学(CFD)模型,详细分析了缸内各区域的温度和组分分布特点.结果表明:加入乙醇直喷可以有效降低CO、NOx和soot排放,提高乙醇能量占比后,CO、HC和soot排放又有所增加;点火时刻提前,缸内整体温度和压力逐渐增加,NOx排放显著上升,soot排放有所下降,由于局部混合气质量变差,燃料不完全燃烧导致CO和HC排放有所增加,同时受过冷壁面淬熄效应的影响,作为未燃碳氢(UHC)排出的燃料也会提高HC排放;乙醇喷射时刻提前,燃料有更充分的时间进行蒸发混合,缸内燃烧状况得到优化,CO和soot排放减少,NOx排放呈上升趋势,间隙效应和壁面油膜吸附作用的增强导致HC排放呈上升趋势.     

基于改进AWNN的风电功率超短期多步预测

为提高风电功率超短期多步预测精度,针对梯度修正学习算法采用随机初始化网络参数训练自适应小波神经网络(AWNN)易陷入局部最优的缺点,将粒子群(PSO)算法和差分进化(DE)算法相结合,提出利用IPSO-DE算法优化AWNN的初始化网络参数,得到改进AWNN模型(IAWNN)并将其用于风电功率超短期多步预测.仿真结果表明...