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Development of Proteinous Bioplastics Using Bloodmeal   总被引:1,自引:0,他引:1  
The aim of this work was to investigate the use of bloodmeal as a thermoplastic biopolymer. Processing required water and chemical additives to perform three main functions: breaking covalent cross-links using sodium sulfite (SS), sodium dodecyl sulfate and urea as processing aids, and evaporating some processing water to allow formation of new interactions to stabilize the final structure. Extrusion was only possible in the presence of SS and strongly influenced by water and urea content. It was found that once water had been removed, mechanical properties increased significantly, indicating the formation of new intermolecular forces. SDS was required for processing and consolidation, but, it may restrict formation of new intermolecular forces, if used in excessive quantities. Materials based on optimal additive levels had a tensile strength of 8 MPa, Young’s modulus of 320 MPa and toughness 1.6 MPa m½.  相似文献   
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A large copper–nickel smelter complex is located at the Kole Penninsula, Russia, close to the Norwegian border. Trace-element concentrations in surface sediments (0–0.5 cm) and pre-industrial sediments from 45 lakes in the region were used to uncover spatial deposition patterns and contamination factor of sediments. Elevated concentrations were found, especially for Ni and Cu, but also for Pb, Co, Hg, As, and Cd. Highest concentrations were found up to 20 km from the smelter, but the concentrations decreased exponentially with distance from the smelter. Increasing Ni, Cu, As, and Hg concentrations from sub-surface to surface sediments were found for lakes at intermediate distances (20–60 km). This may reflect recent changes in atmospheric depositions, as shown in nearby Norwegian areas. However, we cannot rule out that this also may have been caused by diagenetic processes, especially for the most redox-sensitive elements such as As.  相似文献   
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We investigated relationships among North Atlantic Tigriopus brevicornis populations and their relationships to Mediterranean T. fulvus and North American T. californicus, using crossing experiments and mitochondrial DNA sequencing. All T. brevicornis populations tested were interfertile, while interspecific crosses produced either no offspring or offspring that did not survive past the larval stage, with the exception of a few T. brevicornis × T. californicus crosses that produced mature adults. DNA sequencing of a fragment of mitochondrial cytochrome oxidase I (COI) showed that samples of T. brevicornis from Iceland, the Faroes, Ireland, Scotland and Nova Scotia formed a single shallow clade. In contrast, T. brevicornis from more southern populations in France and Portugal formed a clade with substantially greater branch lengths. Tigriopus brevicornis was monophyletic, and T. brevicornis plus Mediterranean T. fulvus were together also monophyletic. The phylogeography of T. brevicornis closely mirrored that found in T. californicus, with substantially reduced interpopulation divergence at northern latitudes. The known distribution of T. brevicornis in Iceland and the Faroes is shown and dispersal mechanisms and habitat selection briefly discussed.  相似文献   
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The field of prenatal screening and diagnosis for fetal anomalies has been marked by a rapid succession of technological advances, including most notably, chromosomal microarray analysis, and next generation sequencing. Despite the diagnostic advantages of these technologies, their incorporation into prenatal testing has created additional challenges of revealing genomic variants of unknown or uncertain significance, and secondary findings. While detailed posttest counseling about uncertain variants is best performed by medical geneticists, many of the screening and diagnostic tests that lead to this information are actually ordered by general maternity health care professionals (HCPs), such as obstetricians, midwives, and family physicians. Maternity HCPs support pregnant women through to the conclusion of their pregnancy and the postpartum period, and thus are close observers of the psychosocial impart of fetal genomic uncertainty on women and their families. While there have been many studies exploring the handling of genomic uncertainty by genetics HCPs, there has been relatively less attention paid to maternity HCPs without speciality training in genetics. This review explores the current literature surrounding nongenetic maternity HCPs' views and experiences of genomic uncertainty and returning uncertain results in the prenatal setting.  相似文献   
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The U.S. Army Corps of Engineers (US ACE) is responsible for conducting the cleanup of radiological contaminated properties as part of the Formerly Utilized Sites Remedial Action Program. One property is the Rattlesnake Creek (RSC) portion of the Ashland sites. The RSC stream sediments are contaminated with thorium‐230, radium‐226, and uranium. The US ACE is closing RSC using protocols contained within the Multi‐Agency Radiation Survey and Site Investigation Manual (MARSSIM). At RSC, the US ACE developed site‐specific derived concentration guideline level (DCGL) cleanup requirements consistent with the MARSSIM guidance. Because of uncertainty about the distribution of contamination within the creek, the US ACE used the Triad approach to collect data and design remedial actions. Systematic planning helped target the areas of concern, develop a conceptual site model, and identify data gaps to be addressed before remediation plans were finalized. Preremediation sampling and analysis plans were designed to be explicitly consistent with final status survey requirements, allowing data sets to support both excavation planning needs and closure requirements in areas where contamination was not encountered above DCGL standards. Judicious use of real‐ time technologies such as X‐ray fluorescence and gamma walkover surveys minimized expensive off‐ site alpha spectrometry analyses, and at the same time provided the ability to respond to unexpected field conditions. © 2004 Wiley Periodicals, Inc.  相似文献   
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