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971.
生物光学传感器是一种对生物物质敏感并将其浓度转换为光信号,再由光电器件转换成电信号进行检测的仪器。由于随着微加工技术和纳米技术的进步,生物光学传感器将不断的微型化,各种便携式生物光学传感器的出现使得人们在家中进行疾病诊断、在市场上直接检测食品及在野外快速检测环境污染成为可能。便携式生物光学传感器一般由光源、光学通路和光电元件三部分组成。传感器结构中各个组件的优化处理将有利于检测设备在实际运用中的便利性和在复杂环境中的适用性,同时也有利于提高生物检测的灵敏度。主要从激励光源的选择、生物光学检测的原理、用于传感光源分析的半导体光敏元件3方面,描述近年来常见的便携式生物光学传感器的研究进展。未来生物检测器件将趋于成本低廉、便携快捷、智能高效等特点,基于生物光学反应特性的研究和传感器结构制备的优化将使得便携式生物光学传感器在未来传感检测应用中具有巨大的商业价值和广泛的实用价值。  相似文献   
972.
A shortcoming in current data quality assessment schemes is that the data quality information is not used systematically to identify the critical data in a life cycle inventory (LCI) model. In addition, existing criteria employed to evaluate representativeness lack relevance to the specific context of a study. A novel framework is proposed herein for the evaluation of the representativeness of LCI data, including an analysis of the importance of the data and a modification of quality criteria based on unit process characteristics. Temporal characteristics are analyzed by identifying the technology shift, because data generated before this time are considered outdated. Geographical and technological characteristics are analyzed by defining a “related area” and a “related technology,” which is done by identifying a number of relevant geographical and technical factors, and then comparing the collected data with these factors. The framework was illustrated in a case study on household waste incineration in Denmark. The results demonstrated the applicability of the method in practice, and they provided data quality criteria unique to waste incineration unit processes, for example, different time intervals to evaluate temporal representativeness. However, the proposed method is time demanding, and thus sector‐level characteristic analyses are feasible instead of the user having to do the analyses.  相似文献   
973.
974.
Soybean is globally cultivated primarily for its protein and oil. The protein and oil contents of the seeds are quantitatively inherited traits determined by the interaction of numerous genes. In order to gain a better understanding of the molecular foundation of soybean protein and oil content for the marker-assisted selection (MAS) of high quality traits, a population of 185 soybean germplasms was evaluated to identify the quantitative trait loci (QTLs) associated with the seed protein and oil contents. Using specific length amplified fragment sequencing (SLAF-seq) technology, a total of 12,072 single nucleotide polymorphisms (SNPs) with a minor allele frequency (MAF)?≥?0.05 were detected across the 20 chromosomes (Chr), with a marker density of 78.7 kbp. A total of 31 SNPs located on 12 of the 20 soybean chromosomes were correlated with seed protein and oil content. Of the 31 SNPs that were associated with the two target traits, 31 beneficial alleles were identified. Two SNP markers, namely rs15774585 and rs15783346 on Chr 07, were determined to be related to seed oil content both in 2015 and 2016. Three SNP markers, rs53140888 on Chr 01, rs19485676 on Chr 13, and rs24787338 on Chr 20 were correlated with seed protein content both in 2015 and 2016. These beneficial alleles may potentially contribute towards the MAS of favorable soybean protein and oil characteristics.  相似文献   
975.
Lithic miniaturization was one of our Pleistocene ancestors' more pervasive stone tool production strategies and it marks a key difference between human and non‐human tool use. Frequently equated with “microlith” production, lithic miniaturization is a more complex, variable, and evolutionarily consequential phenomenon involving small backed tools, bladelets, small retouched tools, flakes, and small cores. In this review, we evaluate lithic miniaturization's various technological and functional elements. We examine archeological assumptions about why prehistoric stoneworkers engaged in processes of lithic miniaturization by making small stone tools, small elongated tools, and small retouched and backed tools. We point to functional differences that motivate different aspects of lithic miniaturization and several instances where archeological systematics have possibly led archeologists to false negative findings about lithic miniaturization. Finally, we suggest productive avenues by which archeologists can move closer to understanding the complex evolutionary forces driving variability in lithic miniaturization.  相似文献   
976.
Real-time monitoring of cell cultures in bioreactors can enable expedited responses necessary to correct potential batch failure perturbations which may normally go undiscovered until the completion of the batch and result in failure. Currently, analytical technologies are dedicated to real-time monitoring of bioreactor parameters such as pH, dissolved oxygen, and temperature, nutrients such as glucose and glutamine, or metabolites such as lactate. Despite the importance of amino acids as the building blocks of therapeutic protein products, other than glutamine their concentrations are not commonly measured. Here, we present a study into amino acid monitoring, supplementation strategies, and how these techniques may impact the cell growth profiles and product quality. We used preliminary bioreactor runs to establish baselines by determining initial amino acid consumption patterns, the results of which were used to select a pool of amino acids which gets depleted in the bioreactor. These amino acids were combined into blends which were supplemented into bioreactors during a subsequent run, the concentrations of which were monitored using a mass spectrometry based at-line method we developed to quickly assess amino acid concentrations from crude bioreactor media. We found that these blends could prolong culture life, reversing a viable cell density decrease that was leading to batch death. Additionally, we assessed how these strategies might impact protein product quality, such as the glycan profile. The amino acid consumption data were aligned with the final glycan profiles in principal component analysis to identify which amino acids are most closely associated with glycan outcomes.  相似文献   
977.
The cereal stemborer Chilo partellus (Swinhoe) (Lepidoptera: Crambidae) is a major insect pest of sorghum (Sorghum bicolor L. Moench) and maize (Zea mays L.) in Africa. Trap cropping systems have been shown to be a valuable tool in management of this pest. To optimize trap cropping strategies, an understanding of host‐plant preference for moth oviposition and host suitability for larval survival on potential trap plants is a prerequisite. Therefore, we assessed seven brachiaria accessions (Poaceae) for preference by C. partellus moths and subsequent larval performance. In two‐choice tests with a local open‐pollinated maize variety (cv. Nyamula), significantly higher numbers of eggs were deposited on brachiaria accessions Marandu, Piata, and Xaraes than on maize, whereas fewer eggs were recorded on plants of Mulato II, Mulato I, and Cayman. There was a significant and negative correlation between the trichome density on plant leaves and C. partellus oviposition preference for brachiaria. In addition to poor larval performance on brachiaria, there was no clear ranking in the accessions regarding larval orientation, settling, arrest, and food ingestion and assimilation. First instars did not consume leaf tissues of brachiaria plants but consumed those of maize, which also suffered more stem damage than brachiaria plants. No larvae survived on brachiaria plant tissue for longer than 5 days, whereas 79.2% of the larvae survived on maize. This study highlights the preferential oviposition of C. partellus on brachiaria plants over maize and the negative effects that these accessions have on subsequent larval survival and development. Our findings support the use of brachiaria as a trap crop for management of C. partellus through a push‐pull technology.  相似文献   
978.
Due to the critical roles of glycoproteins in the activities of cells to tissues, mapping of liver glycoproteome may provide valuable basic information for finding disease marker proteins. In this study, Datura Stramonium Agglutinin (DSA) was chosen to enrich N-linked glycoproteins for its broader specificity with tri- or tetra-antennary complex type. DSA affinity glycoproteins’ profiles of human liver tissue were generated by two-dimensional electrophoresis (2-DE) followed by glycoprotein staining based on multiplexed proteomics (MP) technology. 64 ± 3 (n = 3) protein spots were detected and 41 of glycoproteins were identified via peptide mass fingerprinting (PMF) using MALDI-TOF-MS/MS and annotated to IPI databases. Identified glycoproteins definitely take part in the regulation of cell cycle and metabolic processes. The detailed carbohydrate moiety of some glycoproteins might be concluded according to the literatures. The construction of DSA affinity glycoprotein database would contribute to the subsequent research.  相似文献   
979.
随着内镜技术的发展,放大内镜在临床中的应用尤为受到重视,并越来越多运用于临床诊断。目前新型的放大内镜可清晰显示消化道粘膜腺管开口和微细血管等细微结构的变化,从而,发现和诊断普通内镜难以发现的一些早期病变,特别是早期恶性肿瘤及其癌前病变。近年来在放大内镜检查中加上染色对比技术及窄带成像等技术,使放大内镜的运用得到进一步拓展。本文就放大内镜对结节性胃炎及其相关病变的诊断价值作一综述。  相似文献   
980.
 研究了田间缓慢干旱胁迫下,抗旱性不同的两个小麦(Triticum aestivum)品种的生长状况、质膜极性脂脂肪酸组成以及质膜关键酶活力的变化。在小麦生长发育的早期,干旱胁迫使其叶片质膜极性脂脂肪酸不饱和度下降、质膜微囊消耗O2的速率升高、膜蛋白含量降低、H+-ATPase (EC 3.6.1.35)活力下降、5'-AMPase (EC 3.1.3.5)活力大幅度升高;在小麦发育的后期,随着干旱的持续,小麦叶片质膜的极性脂脂肪酸不饱和度不变或升高、质膜微囊消耗O2的速率降低、膜蛋白含量与H+-ATPase活力升高、5'-AMPase活力下降。以上结果表明,小麦在发育的早期阶段对干旱较敏感,其细胞质膜流动性降低、细胞中能荷贮备降低;而在后期,则又表现出对干旱的适应。这些结果将有助于阐明自然干旱条件下植物的抗旱机制。  相似文献   
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