Application of Bayesian Networks in the development of herbs and spices sampling monitoring system

Knowing which products and hazards to monitor along the food supply chain is crucial for ensuring food safety. In this study, we developed a model to predict which types of herbs and spices products and food safety hazards should preferentially be monitored at each level of the supply chain (suppliers, border inspection points, market and consumers). A Bayesian Network method was used to develop a model based on notifications reported in the Rapid Alert System for Food and Feed and the database of the Dutch national monitoring program for chemical contaminants in food and feed over the period 2005–2014. The model was constructed by randomly selecting ca. 80% of the 3126 data records and validated using the remaining ca. 20% of the records. Model validation showed that the prediction accuracy was higher than 85%. Results showed that the sampling plan is closely related to the place where the products are checked along the supply chain, the products and the country of origin. Our approach of integrating different data sources and considering the entire supply chain can support industry and authorities at border inspection points and at all control points along the herbs and spices supply chain in setting priorities for their monitoring program.     

Development of single nucleotide polymorphism markers from ESTs for discrimination between domestic and imported manila clams,Ruditapes philippinarum

Large amounts of the manila clam, Ruditapes philippinarum, have been imported from Dalian (China) recently to meet the increasing demand in Korea. To ensure the quality and safety of the domestic marine product, it is necessary to be able to distinguish between domestic manila clams and clams that are imported from Dalian, China. We developed expressed sequence tags (ESTs)-derived single nucleotide polymorphism markers using 454 pyrosequencing. A total of 780,000 ESTs were assembled, and 49,540 putative SNPs were identified from 46,405 contigs. Twenty-one polymorphic SNPs from 11 primers were finally selected as diagnostic markers. Genotype analysis showed that 21 SNP markers had the opposite alleles (transitions or transversions) between domestic and imported samples, which were useful for distinguishing clam origins. The GENECLASS 2.0 program was used to estimate the ability of the markers in the discrimination between domestic and imported populations. The 21 SNP markers had 98.96% ability to discriminate domestic manila clams and 100% ability to identify those imported. These markers could be useful for discriminating between domestic and imported manila clams and can contribute to the prevention of falsified labeling of this species.     

Characterization of a SNPs panel for meat traceability in six cattle breeds

Development of DNA technologies makes today possible implementation of conventional beef traceability systems with molecular methods. In the recent past, microsatellites have been the most used marker for individual assignment, however single nucleotide polymorphisms (SNPs) is now replacing them. With the aim to provide a set of SNPs useful for bovine meat traceability we have tested 63 SNPs for the ability to identify single individuals in six European cattle breeds. Eighteen highly informative SNPs located in different genes, have been selected. By using this panel of SNPs the probability that one individual is incorrectly assigned ranges from 1.39 to 0.07 out of 1 million, depending on the breed.     

基于TCS3414的石油产品色度测定传感器

 针对我国目前石油产品色度目视测定法的不足,设计了一种基于 TCS3414数字传感器的透射式色度传感器,改进了石油产品色度测定的关键过程,替代人眼对油品色度进行区分。主要采用 CIE-1937色度公式,对测试样品的色度值进行处理;并根据测量要求,采用Light-Emitting-Diode (LED)设计了与之配套的标准光源系统;针对测定要求,编写了相应的测量程序。结果表明,该传感器具有测量速率快、精度高、稳定性好的特点,能够减轻测试人员的劳动强度,同时能够消除观测行为的主观性和不一致性。该种色度传感器具有较大的应用价值。     

Potentials and caveats with oxygen and sulfur stable isotope analyses in authenticity and origin checks of food and food commodities

Analyses of stable isotope ratios are officially accepted methods in food authenticity and origin determination. They are routinely practiced by empirical comparison of the unknown samples' δ values with those of authentic material. However, as the isotope characteristics of food are influenced by many parameters, it is desirable to also study and use causal correlations of isotope fractionations for the interpretation of experimental data. Corresponding potentials and limits are outlined for oxygen and sulfur stable isotopes.In the natural water cycle, plant leaf and animal cell water are the most important sources for food integrated water and organically bound oxygen. The way from sea water to fruit juice water and to organic matter and the integrated isotope fractionations are shown and the possibilities and limits for the assignment of juices and wine to their geographical origin, history and authenticity are deduced. The oxygen flux and isotopic balance in animals and the sources and drains of animal body water are outlined and the problems and limits for its suitability as a bioindicator for origin assignments of animal food products are discussed. The potential of the δ¹⁸O value of organically bound oxygen is demonstrated.The sulfate reduction in plants is accompanied by isotope fractionation but as normally no sulfur is excreted, the δ³⁴S value of bulk plant matter is identical to that of the primary local source. Small differences in the δ³⁴S values of plant compartments are often due to differences in their abundance of main S-containing ingredients, as residual sulfate and cysteine or methionine containing proteins. This is similar with animal tissues and products. Therefore, the sulfur isotope analysis of the bulk matter or of defined fractions of plant and animal samples is an ideal and reliable tool for food origin and authenticity proof and for archaeological and animal migration research.     

岩石中C1-C12PNA组份的分析方法

本文介绍研究岩石中C₁-C₁₂PNA组份的一种分析方法.该方法在90-100℃进行真空脱气,脱气条件严格探制,始终保持一致,不但脱气率高、重现性好,而且分离的组份不失真.测定结果具有代表性.另外,在优选条件下,实测C₁-C₅校正因子,将HP5880C₅-C₀PNA程序收进为C₁-C₁₂PNA程序.这就充分利用了仪器功能,是目前研究C₁-C₁₂PNA组份的一种较为有效的分析方法.      

不同类型有机质生物产甲烷模拟实验研究

为研究不同类型有机质的生物产甲烷能力和特征,选择了代表藻类、水生草本植物、陆生草本植物和泥炭的6个样品进行生物模拟实验研究。实验气体产物的分析结果揭示:不同类型有机质生物产甲烷潜力差异大,藻类和泥炭的产气能力相差可达百倍,藻类等优质有机质对生物气生成和成藏的贡献值得关注;不同类型的有机质生物转化率相差巨大,进行生物气源岩评价时应予以考虑;生物甲烷的碳同位素值受生成过程中碳同位素分馏效应和母质碳同位素的双重控制,分布范围较宽,生物二氧化碳的碳同位素明显偏重。建议鉴别气藏中天然气的成因时,应结合甲烷碳同位素、二氧化碳碳同位素和天然气组分等数据进行多参数综合判识。      

COOL SHALLOW ORIGIN OF PETROLEUM—MICROBIAL GENESIS AND SUBSEQUENT DEGRADATION

The thermodynamic equilibria of petroleum hydrocarbons and the geographic and depth distributions of oil occurrences suggest that petroleum is formed at shallow depths and low temperatures. The currently prevailing theory of origin from kerogen is inconsistent with known data, especially in relation to the non-marine oils of China.
As an alternative, a hypothesis of origin by microbial diagenesis is proposed. Microbial activities are ubiquitous at depths of less than 2,800 m. Sedimentary organic matter is first transformed into microbial lipids which migrate, accumulate and are finally converted into petroleum at 50-8OC. The energy enrichment process is performed first by microbial activities and then by heat. This process is irreversible in strictly anaerobic conditions because anaerobes cannot utilize hydrocarbons.
The dependence of the efficiency of primary migration upon the pore geometry of source rocks and upon the dimensions of microbial remains deserves emphasis.
The diagenesis of carbonate sediments is characterised by the "openness" of the systems, and by the facility with which local dissolution and reprecipitation occur. If the deposition of a carbonate sediment is sufficiently rapid, and is followed by a quickly-consolidated cover so as to prevent the supply of molecular oxygen for microbes, much pore space and hence pore water may be retained within the sediment, so that it becomes a possible source bed. The carbon and oxygen isotope compositions of carbonate minerals can be used as indicators to define both carbonate and clastic source beds.
Volcanic hydrogen gas ascending into a sedimentary basin may increase the petroleum potential of the basin by supporting the growth of anaerobes which produce source material.     

准噶尔盆地陆南地区油气成因

陆南地区侏罗系和白垩系油气勘探获得重大突破,但其油气成因及来源存在争议。采用全烃地球化学方法,对天然气、原油轻烃和生物标志物特征进行分析,并与周缘构造油气特征进行对比,明确了陆南地区油气成因及来源。该区原油碳同位素较轻,轻烃庚烷值和异庚烷值较小,甲基环己烷含量较高,C₂₈甾烷丰度较低,与莫北凸起原油明显不同,与滴南凸起南分支原油和东道3井白垩系储层抽提物特征基本一致;天然气组分和甲、乙烷碳同位素特征与莫北凸起天然气以及典型的石炭系来源天然气均不同。结合区域构造和烃源岩分布特征,指出陆南地区浅层原油和天然气源区均为东道海子凹陷,原油主要为二叠系平地泉组成熟阶段产物,并存在侏罗系源岩成熟阶段产物的混合;天然气主要为石炭系高-过成熟阶段产物,存在二叠系来源的成熟阶段产物的混合。该区下步勘探应往东道海子凹陷延伸,凹陷北斜坡迎烃面大量发育的岩性圈闭和构造-岩性圈闭具有巨大勘探潜力。     

耦合势有限体积法模拟海洋移动导线源三维频率域电磁响应

本文采用耦合势有限体积法建立了一套快速计算海洋移动导线源电磁响应的三维数值模拟技术。基于电场矢势标势分解将Maxwell方程转换为关于矢势和标势的亥姆霍兹方程;采用洛伦兹规范整理得到对称形式的离散系数矩阵。对导线源采用直接离散方法,基于ILUT （Incomplete LU Preconditioner with Threshold）预处理的BICGSTAB （Biconjugate Gradient Stabilized）迭代算法实现离散线性方程的求解。为了减少移动源总的计算时间,提出采用解的初值重置技术加快正演模拟的速度,即利用发射源移动前的电磁场响应作为发射源移动后的离散方程的初始解。数值计算结果表明：对导线源采用直接离散方法,当导线源的长度大于源周围网格长度的4倍以上时,源附近离散误差显著减小;相比常规的直接迭代算法,采用解的初值重置技术能够减少迭代次数、提高正演计算速度。     

东营凹陷沙三段烃源岩生烃模式研究

为了进一步明确分散有机质(一般烃源岩)与有机质富集层(优质烃源岩)生烃过程的差异,采用东营凹陷沙三段中、下亚段烃源岩岩心进行生排烃模拟实验。结合地质剖面分析,认为沙三段中、下亚段烃源岩的生烃特征有明显的不同。沙三段中亚段主要生烃阶段为Ro大于0.5%;沙三段下亚段在Ro为0.4%-0.5%时可生成少量低熟油,当Ro大于0.5%时进入成熟阶段,具有较高的油气产率。沙三段下亚段烃源岩比中亚段明显具有更高的生烃潜力,且生烃区间较大。这取决于其特定的沉积环境所形成的烃源岩在有机质类型、富集程度等方面的差异。     

合成HKUST-1金属有机骨架材料的母液及其再结晶性能

以硝酸铜为金属离子、1,3,5 均苯三甲酸（H3BTC）为配体,在水热条件下合成了铜基金属有机骨架材料（HKUST 1）。以甲烷作为吸附存储对象,研究了HKUST 1材料及其母液再结晶材料理化性质的变化趋势,得到其甲烷吸附等温线。结果表明,经过3次母液再结晶的产物仍然具有与HKUST 1相似的晶体结构和微孔结构,其BET比表面积和微孔体积分别为1984 m2/g和0722 cm3/g。在25℃和3500 kPa条件下,3次再结晶产物的甲烷吸附量为207 cm3/g,母体HKUST 1材料的甲烷吸附量为226 cm3/g,说明再结晶产物具有一定的气体吸附存储能力和应用价值。。     

α-烯烃合成减阻剂的研究

在管输流体中加入减阻剂是提高输送能力的有效方法。以α-烯烃为原料,利用正交试验法确定减阻高聚物α-烯烃的最优配方和合成条件,分析了主催化剂、助催化剂用量、反应温度和反应时间等因素对聚合产物的影响程度,制定出可行的试验方案。在优化条件下合成的减阻剂,对于对0号柴油,流体雷诺数6000,添加量10μg/g时,减阻效果优于同类产品。     

Microsatellite high resolution melting (SSR-HRM) analysis for authenticity testing of protected designation of origin (PDO) sweet cherry products

DNA based methods have been employed recently for plant species identification and their ingredients in the final food products. The aim of this work was to setup a microsatellite-based method not only to distinguish sweet cherry cultivars but also to compare different techniques for DNA isolation and DNA fragment analysis for verifying the presence of protected designation of origin (PDO) sweet cherry, at the cultivar level, in sweet cherry processed products. Thirteen microsatellites were tested and the combination of the amplification profiles of six of them, characterised by high polymorphism and simple electrophoretic patterns, enabled to distinguish and identify a PDO sweet cherry cultivar used for sweet cherry products. The obtained amplicons were all in the range of 68–258 bp, and were analyzed by capillary electrophoresis (CE) and High Resolution Melting (HRM) analysis. We compare the results obtained by both methods and analyze the differences observed. Dendrograms were constructed using data from HRM analysis and fragment analysis indicating a higher resolution capacity of the HRM method compared to fragment analysis. Moreover, costs, throughput and difficulties to implement HRM analysis and CE methods in the laboratory are discussed. In conclusion HRM analysis can be a cost effective alternative method, with higher resolution, not only to genotype sweet cherry cultivars but also to extend the use to process sweet cherry products using microsatellite markers.     

SOME OPEN QUESTIONS RELATING TO THE PETROLEUM PROSPECTS OF LEBANON*

The history of petroleum exploration in Lebanon and the known stratigraphic succession and structural evolution are briefly reviewed. The negative results of the six relatively-deep exploration boreholes so far drilled cannot be regarded as condemning the petroleum potential of Lebanon, in view of the fact that none explored formations older than the earliest exposed (Lower Jurassic) nor the offshore, and particularly in view of the many hydrocarbon indications encountered, especially when the earlier and recent geochemical work results on source rock potential and origin of shows are considered. Correlation with updated surface and subsurface data from Syria and Jordan enhance the probability of favourable seal formation development in the Late Triassic under Lebanon while favourable location for source/reservoir rock facies emerges when the palaeogeography is considered; postulated Palaeozoic facies also offer favourable potential. The effects of limited extrusive phases in the Late Jurassic/Early Cretaceous and the Late Neogene are examined and considered as non-critical to hydrocarbon accumulation other than on a very limited local structure scale, while the structural effects of Neogene horizontal displacements along the length of the country are taken into account in the presentation of three exploration options designed to look thoroughly at pre-Jurassic prospects.     

Tricyclic terpane geochemistry of source rocks from Northwestern and Central Niger Delta

This distribution of tricyclic terpanes in source rocks from the northwestern and central Niger Delta was used to evaluate their origin, depositional environment and thermal maturity. The rock samples were extracted using Soxhlet extraction method and the saturated hydrocarbon fraction was analysed for biomarkers using gas chromatography-mass spectrometry (GC-MS). The values of soluble organic matter (SOM) and total hydrocarbons for wells AW and OP source rock samples exceeded the minimum 500 ppm and 300 ppm, respectively with values indicating very good to excellent potential source rocks. The tricyclic terpane source parameters and the complementary distribution of hopanes, regular C₂₇-C₂₉ steranes, n-alkanes and acyclic isoprenoid hydrocarbons showed that samples from well AW consist of mixed marine/terrestrial organic matter while those from well OP consist of organic matter largely from terrestrial origin. The values of Pr/Ph ratio for source rock samples from wells AW and OP indicate deposition of the organic matter under suboxic conditions. Sterane and hopane biomarker maturity parameters indicated that the source rock samples from wells AW and OP are at onset of oil generation and main oil window, Most of the source rock samples from well AW are more thermally mature than those from well OP. The results of tricyclic terpane maturity parameters indicated low thermal maturity for the rock samples from both wells with samples from well AW more thermally mature than those from well OP.     

A Bayesian network to optimise sample size for food allergen monitoring

Generally, sampling size is optimised considering a single specific constraint. However, for financial reasons, only one sample is usually defined and used to satisfy several objectives. It is therefore crucial to choose a sample that meets all the required objectives.This paper proposes an original method for optimising a sample plan to monitor allergen traces in products consumed by allergy sufferers. The proposed method, based on a Bayesian network, enables several different constraints to be considered within a single model and the integration of literature data on concentration levels of allergen traces in food. Moreover, the construction of a three-stage sampling plan took into account the consumption preferences of peanut allergy sufferers between products with or without labels on the presence of allergen traces, and between the categories and subcategories of products. This method was applied to data from the MIRABEL project which aims to assess risks related to peanut traces for French allergy sufferers.The results show how the model used all the available information and constraints to balance the total number of samples set at 900 for food categories/subcategories and labelling types. As required, the model favoured the most consumed product categories and subcategories. At the same time, it increased the number of samples when peanut concentration is low. This helps reduce the uncertainty on peanut concentrations in these products and consequently on risk estimation.In conclusion, the proposed method is a useful tool for public administrations, risk assessors and risk managers to improve sampling plans for monitoring allergen traces or other health hazards in food.     

基于贝叶斯理论的天然气水合物储层弹性—电性数据联合反演

单一的声波或电阻率数据,一般通过简单线性或对数线性岩石物理模型预测天然气水合物储层参数。但声波数据或电阻率数据与储层参数之间存在敏感性差异,使用数据源不同,储层参数预测结果可能会存在很大差异。针对此问题,本文提出在贝叶斯理论框架下基于非线性的简化三相方程和改进Archie公式的声波—电性数据联合反演方法,同时预测天然气水合物饱和度、孔隙度和泥质含量,并可评估预测参数的不确定性。应用合成弹性—声波—电性数据分别进行单一弹性、电性数据试验,以及联合声波—电性数据反演模型试验,并将这些反演算法应用于实际测井数据。反演结果表明,本文提出的联合反演方法能预测出可靠的储层参数,且能有效降低因敏感性、噪声等问题产生的不确定性。     

紫外线作用下道路沥青老化行为研究

为了研究紫外线老化下沥青性能变化,选取同种产地、不同标号的两种基质沥青以及两种常规改性沥青,分析基质沥青在不同紫外线老化后组分变化,研究四种沥青在不同时长紫外绒老化后的三大指标、DSR和BBR试验。结果表明,选用沥青老化后C/H值来评价同种来源基质沥青紫外老化性能是可行的,并可以通过使用DSR、BBR补充评价基质沥青和改性沥青紫外线老化后的高低温流变性能。     

加强行业自律 建立合理的价格体系 维护市场稳定

报告了我国钢管行业2008年及2009年前5个月的基本现状。从企业合同订单情况看,2009年新签约的钢管出口合同量同比减少了50%以上,国内外市场需求萎缩,形势更加严峻。从6个方面分析了金融危机对钢管行业的影响,预测 2009年我国钢管进出口都将减少50%以上,表观消费量与上年持平或增长3%~5%,下半年钢管行业可能面临最为困难的时刻,提出企业应严格控制总量,加快结构调整和优化,以市场为指针,加大新产品开发力度,在保持企业合理利润的基础上,扩大产品出口数量。