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Search Results: 1 - 10 of 3320 matches for " 李婷婷 "
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阿尔茨海默症中Aβ诱导细胞凋亡机制研究进展
Research Progress of Aβ-Induced Cell Apoptosis in Alzheimer’s Disease
 [PDF]

李婷婷, 何玲
Pharmacy Information (PI) , 2016, DOI: 10.12677/PI.2016.52006
Abstract:
细胞的过度凋亡可能是导致AD患者发生神经退行性病变的原因,Aβ作为老年斑的主要成分,是引发AD的关键因素。目前,Aβ诱导细胞凋亡已成为AD机制研究的热点,本文主要对Aβ诱导细胞凋亡的通路进行了综述。
The excessive apoptosis of cell may result in neurodegenerative disease, and as the basis of senile plaque, Aβ is a key factor which induced AD. Now people pay much attention to Aβ-induced cell apoptosis related to the mechanism of AD. This review provides the pathways of Aβ-induced cell apoptosis in major.
积极心理学视角下教师心理健康素质的概念和结构初探
Concept and Structure of Teachers’ Mental Health Diathesis from the Perspective of Positive Psychology
 [PDF]

李婷婷, 刘晓明
Advances in Psychology (AP) , 2014, DOI: 10.12677/AP.2014.46105
Abstract:
教师心理健康素质是心理健康素质研究中与实践紧密联系的一个重要的领域。文章从积极心理学视角探讨了教师心理健康素质的概念,并对教师心理健康素质的结构进行了初步探索,以期为今后的教师心理健康素质问卷编制提供理论分析。
Teachers’ mental health diathesis is one of the important areas that closely links to the research and practice of mental health. The article discussed the concept of mental health diathesis of teachers from the perspective of positive psychology, and explored the structure of teachers' mental health diathesis, so as to provide theoretical analysis for teachers’ mental health diathesis questionnaire.
From Sundial to Atomic Clock: Evolution of Horologe
从日晷到原子钟:计时工具的演进

李婷婷
力学与实践 , 2009,
Abstract: Different Horologes like sundial, machine clock, quartz clock and atomic clock are analyzed. Evolution of horologes based on from natural phenomena, mechanics, to high frequency vibration is elaborated. The escapement mechanism in Chinese chronometer, a transition between clocks based on the first and second principle, is discussed as a technical preparation for the invention of machine clock.
从日晷到原子钟:计时工具的演进
李婷婷
力学与实践 , 2009, DOI: 10.6052/1000-0879-2008-270
Abstract: 通过对日晷、机械钟、石英钟和原子钟等计时工具的考察,阐述了计时工具从基于自然现象,到基于机械结构,再到基于高频振荡的演进过程。指出中国天文钟上的擒纵机构为机械钟的发明提供了技术准备,天文钟是基于自然现象的时钟和基于机械结构的时钟之间的过渡。
0℃冷藏下三文鱼片菌相变化规律及特定腐败菌的分离鉴定
李婷婷
- , 2015, DOI: 10.13982/j.mfst.1673-9078.2015.4.007
Abstract: 以冰鲜的三文鱼片为研究对象,利用形态学观察和16S rDNA序列分析法探究其在0 ℃冷藏过程中腐败菌的变化规律,并结合VITEK2微生物自动鉴定系统对其特定腐败菌进行分离和鉴定。结果表明:0 ℃冷藏三文鱼片在贮藏初期(第0 d)的腐败菌主要为葡萄球菌属(Staphylococcus sp.)、假单胞菌属(Pseudomonas sp.)、片球菌属(Pediococcus sp.)、微球菌属(Micrococcus sp.)、气单胞菌属(Aeromonas sp.)、肉食杆菌属(Carnobacterium sp.)及部分鞘氨醇单胞菌属(Sphingomonas sp.)。随贮藏时间的延长,腐败菌菌相逐渐单一,葡萄球菌属、片球菌属、微球菌属呈明显的下降趋势;气单胞菌属及鞘氨醇单胞菌属完全消失;肉食杆菌属变化较小,而假单胞菌属呈上升趋势且到贮存后期数量占绝对优势。腐败菌的PCR产物经测序后通过NCBI数据库比对,并经MEGA5.05软件构建系统发育树分析及微生物自动鉴定仪共同鉴定,确定荧光假单胞菌(Ps. Fluorescens)为冷藏三文鱼片的优势腐败菌。
Chilled fresh salmon fillets were used for the study; the differential prevalence of spoilage bacteria during storage at 0 ℃ was analyzed by morphological observations and 16S rDNA sequence analysis. In addition, the specific spoilage bacteria were separated and identified using the VITEK 2 automated microbial identification system. The major spoilage bacterial species identified in salmon fillets stored at 0 ℃ during the start of storage (day 0) were Staphylococcus sp., Pseudomonas sp., Pediococcus sp., Micrococcus sp., Aeromonas sp., Carnobacterium sp., and Sphingomonas sp. The phase of spoilage bacteria gradually became unitary with the increase in storage time; a significant decrease was observed in the numbers of Staphylococcus sp., Pediococcus sp., and Micrococcus sp., whereas the Aeromonas sp. and Sphingomonas sp. disappeared completely over time. No significant changes were observed in the Carnobacterium sp; on the other hand, there was a gradual increase in the proportion of Pseudomonas sp., leading to its predominance during the end of the storage time. The sequences, amplified by polymerase chain reaction (PCR), were compared against the sequences present in the National Center for Biotechnology Information (NCBI) database; the phylogenetic tree constructed using the MEGA 5.05 software was used for analysis, and the automated microbial identification system was utilized for all measurements. These results identified Pseudomonas fluorescens to be the dominant spoilage bacterium in refrigerated salmon fillets.
一株嗜水气单胞菌的分离鉴定和不同条件对其群体感应AHLs活性的影响
李婷婷
- , 2016, DOI: 10.13982/j.mfst.1673-9078.2016.2.003
Abstract: 本研究从腐败的大菱鲆中分离得到一株具有群体感应(Quorum Sensing, QS)的细菌,通过生理生化试验、16S rRNA鉴定其为嗜水气单胞菌(Ah-11),采用报告平板打孔法探究其生长阶段N-酰基高丝氨酸内酯(AHLs)活性变化以及环境因素对其分泌的AHLs活性的影响。结果显示,菌株Ah-11能够诱导报告菌株紫色杆菌CV026和根癌农杆菌A136产生颜色反应;菌株Ah-11在生长阶段的AHLs活性随着培养时间的增加呈现先升高后降低趋势;不同碳源的液体培养基对Ah-11分泌AHLs的影响能力由高到低为麦芽糖>葡萄糖>蔗糖>果糖>乳糖>木糖;Ah-11在弱酸或者强碱条件下AHLs活性较低,pH=8.0时AHLs活性最大;较高浓度的氯化钠不仅会抑制Ah-11的生长,同时也抑制其AHLs的分泌,0.5~1.0 g/100 g的氯化钠质量浓度可以增强Ah-11的AHLs活性;菌株Ah-11分泌AHLs的最适温度为28 ℃,高温和低温都会影响其AHLs的分泌。研究证实细菌的群体密度和外界环境因素能够调控嗜水气单胞菌AHLs的分泌。
One quorum sensing (QS) strain was isolated from spoilage bacteria of Scophthalmus maximus and by using classical tests and 16S rRNA gene analysis, it was determined to be Aeromonas hydrophila. The changes in the activity of N-acyl-homoserine lactones (AHLs) during the growth stages of the strain and the effect of different culture conditions on the secretion of AHLs were studied by the punch method. The results indicated that the strain Ah-11 could induce Chromobacterium violaceum CV026 and Agrobacterium tumefaciens A136 to produce color. The activities of AHLs increased first and then decreased during the growth phase. The different carbon sources influenced the activity of AHLs in the following order: maltose> glucose> sucrose> fructose> lactose> xylose. The ability of Ah-11 to produce AHLs was reduced in weak acid and alkalescent environment; the optimum pH fat which Ah-11 could secrete AHLs was pH 8.0. Higher concentrations of NaCl would not only inhibit the growth of Ah-11 but also inhibit the activity of AHLs. The concentration of NaCl (0.5–1.0 g/100g) had a significant effect on the ability of Ah-11 to secrete AHLs. The optimal temperature at which the Ah-11 strain could produce AHLs was 28°C and relatively higher or lower temperatures could inhibit AHL secretion. Quorum sensing systems of Ah-11 were regulated by both the density of the bacteria and by environmental factors.
超声波-酶法联合改性提高酸性条件下大豆分离蛋白的乳化性能
李婷婷
- , 2016, DOI: 10.13982/j.mfst.1673-9078.2016.10.029
Abstract: 为了研究超声波联合酶技术提高大豆分离蛋白(Soybean Protein Isolated,SPI)在酸性条件下(pH 4)乳化性能的效果,本文以大豆分离蛋白为原料,以乳化性能和乳状液粒径为衡量指标,确定超声波联合植酸酶-酸性蛋白酶(Ultrasound combined with phytase-acidic protease,Uphy-aci)改性方法的最适宜条件。研究发现,当SPI浓度6%,植酸酶添加量4 U/g,酸性蛋白酶添加量1500 U/g,植酸酶与酸性蛋白酶的酶解时间分别为50 min和30 min时,改性后的SPI(pH 4)乳化性能明显增加,乳状液粒度减小;通过表面疏水性(H0)和扫描电镜(SEM)分析了超声波-酶复合改性处理的SPI,发现在酸性条件下,SPI表面疏水性含量为487.78,比未改性提高了71.2%,并呈现破碎均一、多孔的微观结构。因此,超声波与植酸酶-酸性蛋白酶联合改性提高酸性条件下SPI的乳化特性等功能性质,并且拓宽了大豆分离蛋白的应用领域。
In order to study the effect of ultrasound-enzymatic modificationon the emulsifying properties of soybean protein isolate (SPI) under acidic conditions (pH 4), SPI was used as the raw material in this study. The emulsifying properties and particle sizes were used as evaluating indices to determine the optimum conditions for the modification method using ultrasound combined with phytase-acidic protease (Uphy-aci). The results showed that, when the SPI concentration was 6%, the amount of phytase was 4 U/g, that of the acid protease was 1500 U/g, and the durations of enzymatic hydrolyses using phytase and acidic protease were 50 min and 30 min, respectively. The emulsion performance was significantly increased and the size of the emulsion particles decreased. The surface hydrophobicity, H0, and the scanning electron microscope (SEM) were used to analyze the structure of SPI under the optimal Uphy-aci conditions. The surface hydrophobicity of SPI was 487.78 under acidic conditions and was enhanced by 71.2% compared to that of the unmodified sample. Moreover, SPI presented a homogeneous and porous microstructure. Therefore, the ultrasound-enzymatic modification method can effectively improve the emulsifying properties and functional properties of SPI in acidic conditions, and expand the applications of SPI.
鲶鱼体表粘液粗提物对铜绿假单胞菌的抑菌机理初探
李婷婷
- , 2015, DOI: 10.13982/j.mfst.1673-9078.2015.7.012
Abstract: 本文以铜绿假单胞菌为研究对象,探讨鲶鱼体表粘液提取物(Catfish Epidermal Mucus Extracts, CEME)对其的抑制效果及抑菌机理。研究表明:当CEME浓度高于0.15%时,鲶鱼体表粘液提取物对铜绿假单胞菌有显著的抑制作用,通过测定微生物的生长曲线可以看出CEME能够有效减缓铜绿假单胞菌的生长速率。进一步使用扫描电镜发现CEME对铜绿假单胞菌的细胞形态结构能够造成明显的损伤,有效破坏微生物细胞膜的完整性。同时CEME还可以导致铜绿假单胞菌细胞膜的通透性增加,从而导致体内小分子物质以及部分大分子物质向外泄漏。应用SDS-PAGE方法发现CEME处理对铜绿假单胞菌的总蛋白和细菌膜蛋白均有显著的影响,它能够抑制菌体某些蛋白的合成,导致胞内蛋白含量的下降和缺失。上述研究结果表明鲶鱼体表粘液提取物对铜绿假单胞菌有较好的抑制效果。
Several techniques were used to investigate the mechanism of antibacterial effect of catfish epidermal mucus extracts (CEME) against Pseudomonas aeruginosa. The results showed that the inhibitory effect was significant when the concentration exceeded 0.15% (mg/mL). The bacterial growth curve showed a decrease and scanning electron microscopy (SEM) showed changes in morphology. This indicated that the primary mechanism of CEME inhibitory action was to damage the bacterial cell membrane integrity. CEME also increased bacterial membrane permeability, which led to leakage of cellular small molecules and a proportion of macromolecules. In addition, sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) revealed that CEME causes obvious changes to bacterial membrane proteins, which led to inhibition of bacterial protein synthesis and subsequent decline and loss of intracellular protein content. These results imply that CEME shows relatively good antibacterial effect on Pseudomonas aeruginosa.
顶空固相微萃取-气质联用技术结合电子鼻分析4 ℃冷藏过程中三文鱼片挥发性成分的变化
李婷婷
- , 2015, DOI: 10.13982/j.mfst.1673-9078.2015.2.040
Abstract: 采用顶空固相微萃取-气相色谱质谱联用(HS-SPME-GC-MS)技术,结合电子鼻,对4 ℃冷藏过程中三文鱼片的挥发性成分进行测定,并探究三文鱼片在4 ℃冷藏过程中挥发性成分的变化。结果表明,HS-SPME-GC-MS方法共检测出288种挥发性成分,主要为醛类、醇类和烃类(烷烃、烯烃、芳香烃)物质,且在冷藏期间挥发性成分中醛类物质不断减少,而酸类物质有积累的趋势,醇类和芳香族类物质则先呈现增加后降低的趋势。烃类物质在第12 d时有最大峰面积值;酯类物质则在第6 d以后出现且为增高的趋势;而胺类等其他物质的含量在冷藏期间波动较大。用电子鼻对三文鱼在冷藏期间挥发性物质进行主成分分析(Principal Component Analysis, PCA)、负荷加载分析(Loadings Analysis, LA)以及线性判别分析(Linear Discriminant Analysis, LDA),所得结果与HS-SPME-GC-MS方法相一致,均表明冷藏三文鱼片在第6 d、12 d及15 d的挥发性成分变化较大,是其新鲜度变化的拐点。
The volatile components of salmon fillets were determined using headspace solid-phase microextraction gas chromatography- mass spectrometry (HS-SPME/GC-MS) combined with the electronic nose technique, and the changes of volatile components during storage at 4 ℃ were also explored. The results showed that the 288 types of volatile components determined by HS-SPME/GC-MS mainly consisted of aldehydes, alcohols, and hydrocarbons (alkanes, alkenes, and aromatics). Additionally, during cold storage, the volatile aldehyde content of salmon fillets decreased continuously, acids showed an increasing trend, and alcohols and aromatics showed a decreasing trend after initial increase. The maximum peak area value of the hydrocarbons appeared on day 12; esters appeared after day 6 with an increasing trend; the contents of amines and other components fluctuated greatly during cold storage. The volatile components of cold-stored salmon fillets, detected by electronic nose, were analyzed by principal component analysis (PCA), loading analysis (LA), and linear discriminant analysis (LDA). The obtained results were consistent with the results of the HS-SPME-GC-MS method, indicating that significant changes in volatile components took place on days 6, 12, and 15, which were the inflection points of the freshness of salmon fillets during refrigerated storage.
食品中嘌呤含量分布及其高效液相色谱检测研究进展
李婷婷
- , 2018, DOI: 10.13982/j.mfst.1673-9078.2018.05.037
Abstract: 嘌呤是一种生物碱,在人体内承担着能量供应、代谢调节及组成辅酶等极其重要的生理功能,嘌呤会在人体内逐步发生氧化代谢并最终生成尿酸。当人体内的尿酸含量高于一定阈值时便会诱发高尿酸血症,继而导致痛风等疾病。而饮食是人体摄取嘌呤的重要途径,食品中的嘌呤含量能够显著影响人体内的尿酸水平。因此,明确食品中的嘌呤含量刻不容缓。本文通过归纳总结,对目前国内外已经测得的不同种类食品中的嘌呤含量进行了综合论述,并对现有的样品前处理方法和高效液相色谱检测方法进行了分析对比,以期为确立统一的嘌呤检测方法,提高食品中嘌呤含量的检测效率及准确度提供理论依据,从而帮助、指导消费者合理均衡膳食,控制嘌呤摄入量,降低痛风的发病率。
Purine is an alkaloid and it plays extremely important physiological functions in humans such as energy supplement, metabolic regulation and coenzyme composition. But it can be converted to uric acid finally via oxidative metabolism. The hyperuricemia can be induced and leads to gout, when the level of uric acid in the body is higher than a certain threshold. Diet is the important source of purine for human and the content of purine in foods can significantly influence the body's uric acid level. Therefore, it is urgent to determine the content of purine in foods. In this paper, the purine contents in different foods were reviewed. And different pretreatment and detection methods were discussed in order to optimize and improve the detection efficiency of the purine detection method. So that we can guide consumers to control the purine intake and reduce the incidence of gout via the balanced diet.
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