临沂市淡水鱼养殖、销售及餐饮环节致病性弧菌污染状况及病原学特征

目的：了解临沂市淡水鱼养殖、销售及餐饮环节中常见致病性弧菌的污染现状,进一步描述病原学特征,为加强本市食源性疾病监测和防控提供依据。方法：在本市3个县区设置采样点,采集养殖场、销售场所、餐馆的鱼样及存养鱼的相关样本,参照《国家食品安全风险监测淡水动物性水产品养殖环节中常见弧菌专项监测工作手册》,进行致病性弧菌的分离与鉴定。结果：在281份淡水鱼及相关样品中,4种常见致病性弧菌均有检出,其中霍乱弧菌的检出率最高,为18.15%（51/281）,之后依次为副溶血性弧菌12.81%（36/281）,溶藻弧菌4.27%（12/281）,创伤弧菌0.71%（2/281）。在养殖(144份样品)、销售（74份样品）和餐饮（63份样品）三个环节霍乱弧菌检出率为16.67%（24/144）、21.62（16/74）、17.46%（11/63）,副溶血性弧菌的检出率为2.78%（4/144）、24.32%（18/74）、22.22%（14/63）,溶藻弧菌的检出率为0.69%（1/144）、8.11%（6/74）、7.94%（5/63）,创伤弧菌的检出率为0.00（0/144）、2.70%（2/74）、0.00%（0/63）。检出的霍乱弧菌均为非O1/O139群,不携带ctxAB毒力基因;在淡水鱼及相关样本中检出的36株副溶血性弧菌中有1株携带trh基因,其余均不携带tdh/trh毒力基因。结论：临沂市淡水鱼养殖、销售和餐饮环节均存在不同程度的致病性弧菌污染,非O1/O139群霍乱弧菌和副溶血性弧菌为主要污染菌,霍乱弧菌污染在三个环节中均存在,副溶血性弧菌污染主要存在于销售和餐饮环节,整个淡水鱼产业链需加强综合监管。     

气相色谱-串联质谱法测定婴幼儿配方乳粉中的丙烯酰胺

建立了婴幼儿配方乳粉中丙烯酰胺的气相色谱-串联质谱的测定方法。样品经水溶解后,用乙酸锌、亚铁氰化钾沉淀蛋白,离心,上清液经溴化衍生后经乙酸乙酯提取,采用气相色谱-串联质谱进行定性定量检测,内标法定量。结果表明,丙烯酰胺浓度为5~500 ng/mL时线性良好（＞0.999）,在10 ~ 40 μg/kg水平的加标回收率为89.4 %~107.2 %,相对标准偏差为3.3 %~7.1%（n=6）,检出限为0.25μg/kg,定量限为0.75μg/kg。该方法线性良好、灵敏度、准确度高,抗干扰能力强,适合婴幼儿配方乳粉中痕量丙烯酰胺的测定。     

Mild Fe-deficiency improves biomass production and quality of hydroponic-cultivated spinach plants (Spinacia oleracea L.)

It is of great practical importance to improve yield and quality of vegetables in soilless cultures. This study investigated the effects of iron-nutrition management on yield and quality of hydroponic-cultivated spinach (Spinacia oleracea L.). The results showed that mild Fe-deficient treatment (1 μM FeEDTA) yielded a greater biomass of edible parts than Fe-omitted treatment (0 μM FeEDTA) or Fe-sufficient treatments (10 and 50 μM FeEDTA). Conversely, mild Fe-deficient treatment had the lowest nitrate concentration in the edible parts out of all the Fe treatments. Interestingly, all the concentrations of soluble sugar, soluble protein and ascorbate in mild Fe-deficient treatments were higher than Fe-sufficient treatments. In addition, both phenolic concentration and DPPH scavenging activity in mild Fe-deficient treatments were comparable with those in Fe-sufficient treatments, but were higher than those in Fe-omitted treatments. Therefore, we concluded that using a mild Fe-deficient nutrition solution to cultivate spinach not only would increase yield, but also would improve quality.     

Regulation and Reconstruction of Cell Phenotype Gradients Along the Tendon-Bone Interface

Tendon–bone interface is prevalent in the human body. It is divided into four zones: tendon (soft tissue), unmineralized fibrocartilage, mineralized fibrocartilage, and bone (hard tissue). Tendon–bone interface is characterized by a cell phenotype gradient that appears in the different zones. The cell phenotype gradients at the tendon–bone interface are orchestrated by specific intracellular molecular mechanisms, extracellular factors, immune signals, and neurovascular factors. These features have inspired scientists to design systems that mimic natural cell phenotype gradients. These biomimetic systems include the construction of cell sheets, regulation of cellular microenvironments, and the design of gradient functional scaffolds. Exploration of methods to mimic cell phenotype gradients is instructional for future clinical applications in reconstituting the tendon–bone interface. The present review elucidates the gradient composition of the tendon–bone interface. The associated regulatory mechanisms and applications are discussed, with the anticipation of creating a mise en scène for future research in interface tissue engineering.     

基于相似度分析的电力信息内网用户行为异常预警方法

用户作为网络的重要主体,对其进行行为分析是掌握网络安全状态的重要手段,且在异常检测中对于潜在威胁挖掘和预警具有重要的意义. 本文从电力信息内网同类型用户间行为存在相似性的角度考虑,基于时间行为序列建模对单个用户的行为进行描述,并通过用户行为相似情况的自学习建立用户间的关联,以行为相似偏差实现异常分析,同时考虑用户基础属性的变化实现异常预警判定. 通过模拟实验,该方法能够有效地利用行为序列间的相似度发现潜在的异常行为并进行预警.     

层次结构K-d树的立体图像快速匹配方法

特征匹配是计算机视觉和图形图像处理领域中很多研究方向的基础,也是当前的研究热点.SIFT （scale-invariant feature transformation）特征因其具有尺度、旋转不变性,对一定范围的仿射及视角变换具有鲁棒性等优点,自David G.Lowe提出后,10多年来一直受到众多研究人员的关注.匹配的快速性和准确性是很多应用对特征匹配的要求,如三维重建中立体图像对（stereo pairwise images,简称SPI）的匹配.针对这一问题,本文以SIFT特征为基础,提出用于SPI匹配的方向大约一致（approximately consistent in orientation,简称ACIO）约束关系,其描述了SPI的匹配特征向量间的空间位置关系,有效地避免了误匹配的发生,提高了匹配的精度;通过对标准K-d树（standard K-dtree,简称SKD-Tree）结构的分析,提出了层次结构K-d树（hierarchical K-d tree,简称HKD-Tree）,将SPI特征集根据ACIO约束关系划分成层次结构并建立映射,该方法缩小了搜索空间,从而达到加速匹配的目的;在ACIO和HKD-Tree基础上,提出了高效快速的匹配算法.实验结果表明,本文所提方法比SKD-Tree方法和最新的级联哈希方法（cascade hash,简称CasHash）在精度上略占优势,但是在匹配速度上比SKD-Tree快一个数量级以上,同时也数倍于CasHash.     

Synergistic Antibacterial Activity with Conventional Antibiotics and Mechanism of Action of Shikonin against Methicillin-Resistant Staphylococcus aureus

Methicillin-resistant Staphylococcus aureus (MRSA) is a troublesome pathogen that poses a global threat to public health. Shikonin (SKN) isolated from Lithospermum erythrorhizon (L. erythrorhizon) possesses a variety of biological activities. This study aims to explore the effect of the combined application of SKN and traditional antibiotics on the vitality of MRSA and the inherent antibacterial mechanism of SKN. The synergies between SKN and antibiotics against MRSA and its clinical strain have been demonstrated by the checkerboard assay and the time-kill assay. The effect of SKN on disrupting the integrity and permeability of bacterial cell membranes was verified by a nucleotide and protein leakage assay and a bacteriolysis assay. As determined by crystal violet staining, SKN inhibited the biofilm formation of clinical MRSA strains. The results of Western blot and qRT-PCR showed that SKN could inhibit the expression of proteins and genes related to drug resistance and S. aureus exotoxins. SKN inhibited the ability of RAW264.7 cells to release the pro-inflammatory cytokines TNF-α and IL-6, as measured by ELISA. Our findings suggest that SKN has the potential to be developed as a promising alternative for the treatment of MRSA infections.     

桑葛降糖粉对四氧嘧啶模型小鼠降糖作用的研究

目的研究保健食品桑葛降糖粉对四氧嘧啶糖尿病模型小鼠皀辅助降血糖作用。方法随机选取10只小鼠为空白组,以四氧嘧啶建立糖尿病小鼠实验组,随机分配为模型组、阳性对照组[3g/(kg×d)]、桑葛降糖粉高、中、低剂量组[7.8、3.9、1.95g/(kg×d)],灌胃给药15d,每次灌胃量均为0.1mL/10g。分别在试验第3、7、11、15d测定各组小鼠皀体重、饮水量和空腹血糖值(fastingbloodglucose,FBG)。在第16d迚行口服葡萄糖耐量试验,分别测定各组小鼠口服葡萄糖0、30、60、120min后皀血糖值,幵计算曲线下面积(areaunderthecurve,AUC)。结果桑葛降糖粉对糖尿病小鼠皀体重影响不显著,但其多饮症状得到明显改善;桑葛降糖粉高、中剂量组均能显著降低小鼠FBG(P0.05),且能显著增加小鼠皀糖耐量(oralglucosetolerance,OGT)(P0.01)。结论桑葛降糖粉能够明显改善糖尿病小鼠皀病症,可以有效降低糖尿病小鼠皀FBG和增加其OGT,因此具有较好皀辅助降血糖作用。