SPME-GC/MS结合主成分分析检测竹叶青茶挥发性香气成分

目的 建立SPME-GC/MS检测竹叶青茶挥发性香气成分的方法,结合主成分分析法探究茶叶特征风味成分。方法 通过系统考察程序升温、载气流速、溶剂延迟时间等GC/MS条件和萃取头种类、萃取时间、萃取温度等SPME条件,确定了最佳试验参数;分析竹叶青茶的VFCs,并采用主成分分析提取其特征风味成分。结果 鉴定出109种VFCs,主要为醇类、醛类、酮类、酯类和烷烃类。结论 SPME-GC-MS法能够有效提取、分离、检测茶叶挥发性香气成分;主成分分析法有助于综合评价茶叶特征风味物质,可用于茶叶的鉴别。     

气相色谱-质谱联用技术在卫生分析中的应用

本文对了气相色谱-质谱联用技术(GC/MS)在卫生分析中的应用进行了综述,较详细地阐述了GC/MS在卫生分析的环境、食品及生化各领域中的应用.GC-MS联用技术具有快速、简便、准确等优点.     

气相色谱一质谱联用技术在卫生分析中的应用

本文对了气相色谱—质谱联用技术(GC／MS)在卫生分析中的应用进行了综述，较详细地阐述了GC/MS在卫生分析的环境、食品及生化各领域中的应用。GC-MS联用技术具有快速、简便、准确等优点。     

GC-MS/MS法测定动物性食品中的克伦特罗残留量

[目的]研究测定动物组织中克伦特罗残留量的GC-MS/MS分析方法。[方法]应用GC-MS/MS技术,采用二级质谱母离子特有的子离子碎片信息进行定性及定量分析。[结果]取样5 g时,该法对克伦特罗的最低检出限为0.034μg/kg,线性范围5~100 ng,不同含量水平加标回收率75%~93%。[结论]GC-MS/MS法具有检测快速、定性定量准确及灵敏度高的优点,可用于测定动物性食品中克伦特罗残留量。     

5种驱蚊止痒产品挥发性成分的快速分析

目的建立一种简单快速分析5种驱蚊止痒产品中挥发性成分的气相色谱-质谱联用法(GC-MS),并分析比较其中成分及使用。方法采用RTX-5MS毛细管柱(30 m×0.25 mm×0.25μm),程序升温,EI离子源,对5种驱蚊止痒产品:清爽花露水、驱蚊花露水、风油精1、风油精2、百草油进行GC-MS分析,并对其挥发性成分进行定性鉴定和定量分析。结果清爽花露水和驱蚊花露水中分别鉴定出10、29种挥发性化合物,主要成分均为乙醇,驱蚊花露水中避蚊胺含量达38.022%,其余多为定香剂、香料等;2种风油精中分别鉴定出31、36种挥发性化合物,其中薄荷脑、水杨酸甲酯含量较高,其他挥发性成分含量较低;百草油中挥发性成分多(62种)且含量较均匀,有α-蒎烯、柠檬烯、薄荷脑、水杨酸甲酯等。结论该方法不需要任何溶剂、任何预处理,简单、快速、准确,适用于驱蚊止痒产品的质量控制和指导人们合理使用。     

固相微萃取技术在化学分析中的应用

固相微萃取技术(SPME)是在固相萃取基础上发展起来的一种新的萃取分离技术。与液—液萃取、固相萃取相比具有操作时间短、样品量少、使用方便、无需萃取溶剂、重现性好,适用于分析挥发性与非挥发性物质等优点。现已被广泛用于环境、药物及生物样品等化学分析领域。该文检索近年发表的文献32篇,对采用SPME法在上述领域的应用及进展进行了评述。     

突发化学性事故有机气体应急检测技术进展

化学性事故的突发,再加上挥发性和半挥发性有机成分的复杂性和扩散性,如何在短时间内对事故现场的未知物进行准确检测,目前已经有很多成熟的检测技术,归纳为两类,一类是现场检测确定检测目标,一般采用快检试剂盒、快检气体管、便携式直读仪器、便携式质谱仪等方法,优点是快速、简便、现场就可以知道检测结果和浓度,缺点是检测项目较单一,多组分的成分难判断,干扰多等。一类是现场检测和实验室检测相结合,在现场测不了的或者成分复杂的样本带回实验室进行分析,采用现场快速检测和实验室检测相结合的方式确定检测目标,常用的有吹扫捕集气相色谱质谱联用技术(PT-GC-MS)、静态顶空-气相色谱/质谱法(HS-GC/MS)、热脱附结合气相色谱-三重四级杆串联质谱(GC-MS/MS)、大气压化学电离-串联质谱法(APCI-MS/MS)、质子转移反应飞行时间质谱仪(PTR-TOF MS),选择性好、灵敏度高,线性关系好,检测限低,相对标准偏差小,并且结果不同仪器的验证不容易出错等。     

人尿中柯铁宁含量的气相色谱-质谱测定法

目的建立利用气相色谱-质谱（GC-MS）联用技术准确测定人尿中柯铁宁含量的方法。方法用β-葡萄糖苷酸酶水解共轭存在的三羟基柯铁宁（THOC）及柯铁宁（COT），以n-丁基乙酸及二氯甲烷混合液（2：1）萃取尿中的柯铁宁成分。应用HP-5MS交联石英毛细管柱进行分离，用GC-MS测定其含量。结果该方法检出限为0．02μg/L，回收率〉90％，平均相对标准偏差为4．30％。结论GC-MS法可以准确测定人尿中柯铁宁含量，满足痕量分析的要求，并具有背景值少、快速、准确可靠等特点，已应用于广州生物库老年人队列大样品量的人尿中柯铁宁的研究。     

GC-MS/MS稳定同位素稀释技术测定蜂蜜中的氯霉素

[目的]建立稳定同位素稀释技术测定蜂蜜中氯霉素(CAP)分析方法。[方法]用氘代氯霉素(D5-CAP)为内标物,以SPC C18固相微萃取小柱净化样品,BSTFA TMCS为衍生剂,应用GC-MS/MS中多离子选择模式(MRM)定性及定量分析。[结果]该法在0.46~9.22 ng内线性良好,相关系数为0.9965,加标回收率79.8%~102%。当称样量为5.0 g时,最低检定浓度为0.02μg/kg。该方法参加国际食品分析能力测试蜂蜜中氯霉素的测定考核,结果满意。[结论]GC-MS/MS稳定性同位素稀释法具有方法稳定、定性定量准确及灵敏度高的优点,可用于蜂蜜中氯霉素测定。     

气相色谱-质谱法同时测定工作场所空气中24种挥发性有机物

目的建立同时测定工作场所空气中24种挥发性有机物的气相色谱-质谱法(GC-MS)。方法采用活性炭管吸附和二硫化碳(CS2)解吸,经DB-5MS毛细管柱分离,GC-MS法测定。结果方法相关系数均在0.999 7以上,最低检出质量浓度为0.1～0.6 mg/m3,相对标准偏差为1.2%～3.8%,解吸效率为78.0%～100.0%。结论该方法准确、灵敏、简便,适用于工作场所空气中24种挥发性有机物的同时检测。     

Hepatitis C virus infection in injection drug users in Bavaria: risk factors for seropositivity

Background: Hepatitis C Virus (HCV) infection is the most common disease among intravenous drug users (IDUs). Patients and method: All patients admitted to the detoxification unit 1991–1997 and meeting ICD-10 diagnosis of opioid dependency were tested for anti-HCV serology. Results: Thousand and forty nine patients were included in the study. About 61.3% of the IDUs were anti-HCV positive. Increasing age (PR: 1.46; 95% CI: 1.34–1.60), living with a significant other drug user (PR: 1.17; 95% CI: 1.05–1.31), history of therapy (PR: 1.62; 95% CI: 1.50–1.74), history of imprisonment (PR: 1.48; 95% CI: 1.36–1.61), history of emergency treatment (PR: 1.23; 95% CI: 1.12–1.35), additional daily consumption of benzodiazepines (PR: 1.10; 95% CI: 1.00–2.21) or alcohol (PR: 1.26; 95% CI: 1.14–1.38), frequency of injecting heroin (daily: PR: 0.86; 95% CI: 0.78–0.96; previously: PR: 1.14; 95% CI: 1.03–1.26) and type of opioid dependency (methadone: PR: 1.26; 95% CI: 1.13–1.41) were significant factors, considered as individual factors, for positive anti-HCV serology. Using multiple logistic regression we found that older age (OR: 3.54, 95% CI: 1.30–9.67), longer duration of opioid use (OR: 5.74; 95% CI: 1.82–18.13), living with a significant other drug user (OR: 1.47; 95% CI: 1.01–2.16), history of therapy (OR: 4.87; 95% CI: 1.67–14.20), history of imprisonment (OR: 1.92; 95% CI: 1.12–3.28), history of emergency treatment (OR: 1.45; 95% CI: 1.06–1.99) and additional daily consumption of alcohol (OR: 1.49; 95% CI: 1.04–2.13) remained independently associated with positive anti-HCV serology. Conclusions: These data support the need for early prevention strategies, namely, education of teachers in schools and further training of counsellors informing IDUs of what they can do to minimise the risk of becoming infected or of transmitting infectious agents to others.     

The quality properties and saturated and unsaturated fatty acid profiles of quail egg: the alterations of fatty acids with process effects

The nutritional composition (moisture, ash, crude protein, available carbohydrates, total lipids), energy value, some quality characteristics (yolk weight, albumen weight and shell weight), cholesterol level and fatty acid profiles of quail egg were determined (p<0.01). The protein content of quail egg was higher than laying hen's egg. The fatty acid composition of quail egg yolk consisted of 24 fatty acids including saturated fatty acids (C14:0, C16:0, C17:0, C18:0, C20:0, C22:0, C24:0), monounsaturated fatty acids (C15:1, C16:1, C17:1, C18:1n9, C18:1n7, C22:1n9, C24:1) and polyunsaturated fatty acids (C18:2n6t, C18:2n6c, C18:3n6, C18:3n3, C20:2, C20:3n6, C20:3n3, C20:4n6, C22:2, C20:5n3, C22:6n3). The total cholesterol level of quail egg was found to be 73.45±1.07 mg/100 g. Linoleic acid (C18:2n6c) (10.28%), arachidonic acid (C20:4n6) (1.92%) and cis-5,8,11,14,17-eicosapentaenoic acid (C20:5n3) (0.63%) were the major polyunsaturated fatty acids in the fatty acid content of quail egg yolk, whereas oleic acid (C18:1n9c) was the major monounsaturated fatty acid comprising 26.71% in the yolk. The palmitic acid (C16:0) and stearic acid (C18:0) levels were 16.62% and 6.89%, respectively. Total omega-3 was detected as 1.16% in raw egg whereas it was 0.82% in soft-boiled (rafadan) egg. The polyunsaturated fatty acid/saturated fatty acid proportion was 0.58 and 0.64 for raw and processed yolk, respectively.     

Artificial oocyte activation: physiological,pathophysiological and ethical aspects

Infertile couples with low oocyte yield in combination with abnormal semen parameters may experience intra-cytoplasmic sperm injection (ICSI) failure. An established factor associated with ICSI failure is oocyte activation deficiency (AOD). The latter originates from seminal contributors, such as phospholipase C-zeta (PLCζ) that is not adequate to produce calcium (Ca²⁺) oscillations for oocyte activation. Apart from this natural activator, other stimulants, such as A23187, ionomycin, strontium chloride or even electric pulses, have been used in embryological laboratories to overcome AOD and ICSI failure. The aim of the present narrative review is to discuss the role of Ca⁺² oscillations in oocyte activation and summarize the evidence concerning the use of oocyte activators as agents for artificial oocyte activation (AOA). Studies in humans and animals have emerged many physiological, pathophysiological and ethical aspects of AOA. In conclusion, in mammalian eggs, the cytosolic Ca⁺² oscillations derive from a periodic release of Ca⁺² from intracellular pools. PLCζ, as well as artificial stimulants, have been used to produce Ca⁺² oscillations for AOA. As the latter may increase the risk of epigenetic induced malformations, further studies are required to clarify whether AOA constitutes an effective and safe method to overcome ICSI failure.

Abbreviations: AOA: artificial oocyte activation; AOD: oocyte activation deficiency; Ca⁺²: Calcium; CAMKII: Ca⁺²/calmodulin-dependent protein kinase II; CICR: calcium-induced calcium-release; DAG: diacylglycerol; GM-CSF: granulocyte-macrophage colony-stimulating factor; ICSI: intra-cytoplasmic sperm injection; InsP₃R: inositol-trisphosphate receptor; IP₃: inositol 1,4,5-trisphosphate; IVF: in vitro fertilization; MAP: mitogen-activated protein; MII: metaphase II; NADP: nicotinic acid adenine dinucleotide phosphate; NO: nitric oxide; PAWP: post-acrosomal WW-binding domain protein; PIP₂: phosphatidylinositol 4,5-bisphosphate; PLC: phospholipase C; PLCζ: phospholipase C-zeta; SOAFs: spermatozoon-released oocyte-activating factors; Sr⁺²: strontium; TFF: total fertilization failure     

Cleavage-stage embryo micromanipulation in the clinical setting

Embryo micromanipulation was developed after introduction of microinjection to overcome infertility. Embryo micromanipulation may be performed at any embryo stage from pronuclear to blastocyst. The technique started out as basic and turned out to be increasingly more complex. Embryo micromanipulation at the cleavage-stage includes a wide range of techniques, from opening the zona pellucida in order to improve the chance of implantation, to removing detrimental components from the embryo to enhance embryo development or blastomeres for preimplantation genetic diagnosis and embryo splitting. Evaluating the impact(s) of different micromanipulation techniques on epigenetics of the embryo and considering quality control during these techniques are important issues in this regard. This review aims to discuss the micromanipulation of cleavage-stage embryos in clinical assisted reproductive technology (ART).

Abbreviations: ART: assisted reproductive technology; ICSI: intracytoplasmic sperm injection; IVF: in vitro fertilization; PGD: preimplantation genetic diagnosis; PZD: partial zona dissection; ZP: zona pellucida; SUZI: subzonal insemination; PVS: perivitelline space; AH: assisted hatching; LAH: laserassisted hatching; ZT: zona thinning; UV: ultraviolet; IR: infrared; PCR: polymerase chain reaction; FISH: fluorescent in situ hybridization; NGS: next generation sequencing; QC: quality control; QA: quality assurance     

Re-imagining occupational therapy clients as communities: Presenting the community-centred practice framework

Background: Occupational therapists’ are increasingly working with communities and providing services at the community level. There is, however, a lack of conceptual frameworks to guide this work.

Aim: The aim of this article is to present a new conceptual framework for community-centered practice in occupational therapy.

Material and Method: The conceptual framework was developed from qualitative multi-case research on exemplars of community participation. The first was, a network of Canadian food security programs, and the second, a rural Australian community banking initiative. Key themes were identified from across the case studies, and cross-case findings interpreted using occupational therapy and occupational science knowledge, and relevant social theory. The outcome is a four-stage, occupation-focused, community-centered practice framework.

Findings: The Community-Centred Practice Framework can be used by occupational therapists to understand and apply a community-centered practice approach. The four stages are: (1) Community Identity, (2) Community Occupations, (3) Community Resources and Barriers, and (4) Participation Enablement.

Conclusions: Further research is needed to trial and critically evaluate the framework, to assess its usefulness as a robust, occupation-focused, frame of reference to guide community-centered practice in occupational therapy.

Significance: The proposed framework should assist occupational therapists to conceptualize community-centered practice, and to utilize and apply theory.     

Anemia and Associated Factors among Pregnant Women Attending Prenatal Care in Rural Dembia District,North West Ethiopia: A cross-Sectional Study

ABSTRACT

Introduction: About 22% of pregnant women are anemic in Ethiopia, but there is a large variation across the country. Hence, the aim of this study identifies the prevalence of anemia and associated factors among pregnant women attending prenatal appointments in Dembia District, northwest Ethiopia.Methods and materials: A facility-based, cross-sectional study was conducted among 713 pregnant women. A multi-stage, stratified sampling technique was used to select the study participants. A structured and pretested questionnaire, laboratory data, and chart review were used to collect data. Bivariate and multivariate logistic regression analyses were used to identify factors associated with anemia in pregnant women.Results: Prevalence of anemia was 32.4% with a majority of these having moderate anemia. Type of health center being rural/urban health center, water sources, days since fasting, 4 weeks of iron supplementation, craving unusual foods, mid-upper arm circumference scores, and decision power were significant predictors of anemia.Conclusion: The present study suggests anemia among pregnant women attending prenatal in Dembia district was high. Working to enhance adherence to iron supplementation and partner involvement for joint decision-making is recommended to avert prenatal anemia. Health-care providers and programmers are advised to pay special attention to rural and fasting pregnant mothers.

Abbreviations: AOR: Adjusted Odd Ratio; CMHS: College of medicine and health sciences; CI: Confidence Interval; HFIAS: Household Food Insecurity Access Scale; RCSI: Reduced Coping Strategies Index; Hgb: Hemoglobin; MCMC: Marco Chain Monte Carlo; EPV: Events per variable; BMI: Body Mass Index; PPS: Population proportionate to size sampling; SRS: simple random sampling; DALYS: Disability-adjusted life years; MUAC: Mid-upper-arm-circumference; WHO: World Health Organization; EDHS: Ethiopian Demographic and Health Survey; SPSS: Statistical package for social science; ANC: Ante natal care; PCA: Principal component analysis; MASL: Meter above sea level; g/dl: gram per decilitre HALE: Health Action Leicester Ethiopia; WDDS: Women’s Dietary Diversity Scale