醋蒜提取物抑菌作用研究

对醋蒜的乙醇提取物(PGEE)、水提物(PGWE)、醋蒜浸泡液(PPG)的抑菌活性进行了研究，测定了各提取物的MIC和MBC，同时对各提取物的耐热性进行了分析，并以鲜大蒜的相应提取物作为对照。结果表明PGEE、PGWE和PGJ的MIC分别为0．313～0．625mg／mL，5～10mg／mL，1．25～2．5mg／mL；鲜大蒜的醇提物(GEE)和水提物(GWE)的MIC分别为0．156～0．313mg／mL和0．625～1．25mg／mL。醋蒜醇提物和浸泡液的抑菌活性较好，且它们抑菌作用的热稳定性优于鲜蒜提取物。     

Evaluation of the antimicrobial activity of aqueous extracts from dry Vaccinium corymbosum extracts upon food microorganism

As blueberries are rich in phenolic compounds, which possess a demonstrated antimicrobial activity, it may be interesting to further elucidate its real potential and properties. As such, the main goal of this work was to evaluate the potential antimicrobial activity of Vaccinium corymbosum dry fruits and leaves aqueous extracts against several contaminants/pathogenic microorganisms while at the same time assessing the effect of V. corymbosum over lactic acid bacteria.     

解淀粉芽孢杆菌HRH317菌株抗菌肽发酵条件优化及其抑菌活性研究

本文以抑菌圈直径为指标,采用单因素试验和响应面法对解淀粉芽孢杆菌HRH317菌株产抗菌肽的发酵条件进行优化,并对该抗菌肽的抑菌谱及其最小抑菌浓度(MIC)进行了研究。得到最佳发酵条件为：pH7.5,装液量为50 mL,接种量3%,培养时间13h、温度38.5℃、转速145r/min,抗菌肽含量441.56±1.24 μg/mL。在此条件下抗菌肽的抑菌圈直径达15.95 mm。针对9种指示菌的抑菌谱结果表明,抗菌肽对枯草芽孢杆菌、金黄色葡萄球菌抑制效果最好,其次是霉菌、酵母菌。其中,抗菌肽对枯草芽孢杆菌、金黄色葡萄球菌的MIC为 3.45 μg/mL,大肠杆菌、白地霉、巴氏醋酸杆菌MIC为6.9 μg/mL,禾谷镰孢菌、黄曲霉、假丝酵母MIC为 55.20 μg/mL,红酵母MIC为110.40μg/mL。     

Biological activities of Solanum paludosum Moric. extracts obtained by maceration and supercritical fluid extraction

Solanum paludosum extracts obtained by maceration (SP-EtOH_CRUDE and SP-EtOH_MARC) and supercritical fluid extraction (SP-SFECO₂) were evaluated. Three extracts with distinct chromatographic profiles were obtained: SP-EtOH_CRUDE, with a complex phenolic composition; SP-SFECO₂, containing methoxylated flavonoids; and SP-EtOH_MARC, which bears mainly polar polyphenols. All extracts were strong antioxidants, as measured using the diphenylpicrylhydrazyl (DPPH) method, xanthine/xanthine oxidase/luminol and iron-induced lipid peroxidation systems. Extracts were also evaluated as modifiers of antibiotic activity in strains of Staphylococcus aureus expressing fluoroquinolone, macrolide and tetracycline efflux proteins. Despite their lack of antibacterial activity, all extracts were able to potentiate antibiotics activities by as much as eight fold. Both the maceration and supercritical fluid extraction processes were adequate to obtain extracts with different biological activities according to their patterns of phenolic compounds. The data suggest that S. paludosum could be a valuable source of antioxidants and putative efflux pumps inhibitors.     

一种基于边缘和MIC算子的医学图像配准

研究基于点特征的图像配准方法。首先利用canny算子提取图像的边缘,然后用MIC角点检测算子提取边缘中的角点,对提取出的角点进行配对后,利用仿射变换实现图像的配准。最后以脑图像配准验证了算法的有效性。     

温度对厌氧环境中硫酸盐还原菌所致铜镍合金腐蚀行为的影响

目的 探究环境因素（温度）在微生物腐蚀（Microbiologically Influenced Corrosion,MIC）过程中的影响以及细菌最适宜的温度条件,初步探索铜合金的MIC机理,为微生物的腐蚀与防护提供依据。方法 利用生物学分析、表面分析以及电化学手段,研究不同温度（25、37、45℃）条件下培养基中硫酸盐还原菌（Sulfate-reducing Bacteria,SRB）的生长状况和铜镍合金表面的腐蚀状态,进而对微生物体系中的MIC行为进行分析。结果 从生物学分析来看,培养周期内SRB细胞的数量先迅速增加,之后又逐渐减少。温度为37℃时,检测出的SRB细胞数和培养基中生成的H₂S最多。从表面分析来看,铜镍合金表面生成不致密的生物膜,在生物膜下面检测出点蚀坑,且点蚀密度小。温度为37℃时,生物膜覆盖的区域最大,且该温度下检测到最大的平均点蚀坑深度,约9.3μm。从电化学分析来看,在各种温度下,浸泡在生物介质中的试样的开路电位（OCP）大致向正方向移动,Rp曲线呈现先上升后下降的趋势,温度为37℃,试样检测出的Rp值最小。结论 温度能够影响SRB所导致...     

Influence of the sulphate reducing bacteria on API‐X70 steel corrosion

The corrosion behaviour of API X70 immersed in a specific medium with a strain of thermophilic sulphate reducing bacteria (SRB) was analysed. Anaerobic corrosion test was carry out for 32 days at 50 °C. During the exposure time, pH, sulphate (SO) and hydrogen sulphide (H₂S) concentration were measured. Corrosion potential, linear polarization resistance and potentiodynamic polarization curve were used in order to get the influence of the SRB in the corrosion phenomenon. Scanning electron microscopy was used to determine corrosion morphology. Results show that the SRB activity influenced the overall corrosion process. The anodic branches in the polarization curves show a passivity feature, whereas, the cathodic branches were not affected. A localized corrosion attack was found.     

MIC2778和MIC2545在USB双限流开关中的应用

MIC2778和MIC2545是Micrel公司生产的用于限流的集成电路,可广泛用于热插拔和即插即用型设备中的限流开关,文中介绍了利用MIC2778和MIC2545设计的限制浪涌电流的电流开关电路。     

开关型电压调节器MIC4680及其应用电路

MIC4680是Micrel公司推出的一种新型开关型电压调节器。它在4－34V的输入电压范围内能输出稳定的固定或要调输出电压。可广泛应用于电源调节卡、正负电压转换器、电池充电以及能驱动外部FET的高电路输出调节系统中。文中介绍了它的主要特点、引脚功能、主要参数和可调输出时的典型电路及设计方法。最后给出了由MIC4680构成的手机电池充电电路和将正＋12V转换成－12V输出的正、负电压转换器等实际电路。     

微波集成介质振荡器的时域有限差分模拟

 本文将Gunn二极管的非线性集中模型编入时域有限差分算法,模拟了微波集成介质腔稳Gunn振荡器的瞬态特性.