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1.
Soybean oil hydrogenation alters the linolenic acid molecule to prevent the oil from becoming rancid, however, health reports have indicated trans-fat caused by hydrogenation, is not generally regarded as safe. Typical soybeans contain approximately 80 g kg−1 to 120 g kg−1 linolenic acid and 240 g kg−1 of oleic acid. In an effort to accommodate the need for high-quality oil, the United Soybean Board introduced an industry standard for a high oleic acid greater than 750 g kg−1 and linolenic acid less than 30 g kg−1 oil. By combing mutations in the soybean plant at four loci, FAD2-1A and FAD2-1B, oleate desaturase genes and FAD3A and FAD3C, linoleate desaturase genes, and seed oil will not require hydrogenation to prevent oxidation and produce high-quality oil. In 2017 and 2018, a study comparing four near-isogenic lines across multiple Tennessee locations was performed to identify agronomic traits associated with mutations in FAD3A and FAD3C loci, while holding FAD2-1A and FAD2-1B constant in the mutant (high oleic) state. Soybean lines were assessed for yield and oil quality based on mutations at FAD2-1 and FAD3 loci. Variations of wild-type and mutant genotypes were compared at FAD3A and FAD3C loci. Analysis using a generalized linear mixed model in SAS 9.4, indicated no yield drag or other negative agronomic traits associated with the high oleic and low linolenic acid genotype. All four mutations of fad2-1A, fad2-1B, fad3A, and fad3C were determined as necessary to produce a soybean with the new industry standard (>750 g kg−1 oleic and <30 g kg−1 linolenic acid) in a maturity group-IV-Late cultivar for Tennessee growers.  相似文献   
2.
Bioabsorbable composites, designed for use as rigid tissue scaffolds, were fabricated by reinforcing free radically cured poly(D,L-lactide) fumarate matrices with absorbable poly(glycolic acid) fibers. To investigate the benefits of an improved fiber/matrix interphase, fiber pretreatments were employed including surface-etching by exposure to mild acidic conditions and incorporation of 3-methacryloxypropyltrimethoxysilane as a coupling agent. SEM of composite fracture surfaces showed that fiber pretreatment yielded improved wetting and encapsulation of the fibers by the matrix resin. The composites fabricated with poly(glycolic acid) fibers which were acid-etched and pretreated with the coupling agent showed an average 41% increase in tensile strength; a representative sample displayed an increase from 73.9 MPa to 105.5 MPa, compared to the composite made from untreated fibers.  相似文献   
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Kindergartners, 3rd, and 6th graders chose classmates whom they would and would not like to have on their team for an academic contest and as playmates. Ss also rated their classmates on likableness and academic ability. At all ages, children's choices for the academic competition and the play situation were significantly associated with their ratings of their classmates' academic and social competence, respectively. Ss typically referred to academic abilities to explain their teammate choices for the academic contest and to social competence or friendship to explain playmate choices. Questions about the stability of classmates' academic and social competencies revealed that not until 6th grade did Ss indicate that there are limits in the degree to which academic and social competencies could improve with effort. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
5.
Molecular model systems based on propyl phosphonic acid (ppa) were studied by means of density functional theory calculations in order to describe the acid-acid interaction and the formation of the hydration sphere. The formation of ppa dimers is reported and the energetic difference between two dimer structures is presented. The hydration sphere of ppa was represented by model systems ppa(H2O)n, for which the system with n=4 formed the first hydration sphere (h1), while n=7 can be considered a good approximation to the complete inner hydration sphere around the phosphonic acid group. The study of the ppa-H+ (H2O)n model systems showed an interesting structural behavior comparatively to the ppa(H2O)n systems. The protonated acids exhibited equivalent phosphorous-oxygen bonds and a general molecular structure is proposed to represent these protonated species.  相似文献   
6.
The improved fracture resistance of whisker-reinforced ceramic-matrix composites involves more than one energy-absorbing mechanism. The possible mechanisms are reviewed and a micromechanical model evaluating the relative contributions to the overall toughness is presented. The mechanisms involve microcracking, load transfer, bridging, and crack deflection. The synergism of these mechanisms is examined using an energy release rate balance equation. The basic assumption of the proposed model is that the load transfer between the matrix and the whiskers is due to Coulomb friction. The model has been applied to an Al2O3/SiC whisker composite and shows reasonable agreement with reported experimental results. The role of the thermal residual stresses is also examined in light of the frictional load transfer assumption.  相似文献   
7.
The United States has historically excelled in the design of products, processes and new technologies. Capitalizing on this historical strength to teach applied mathematics and science has many positive implications on education. First, engineering design can be used as a vehicle for addressing deficiencies in mathematics and science education. Second, as achievement in mathematics and science is enhanced, a greater number of students at an earlier age will be exposed to technical career opportunities. Third, enhancing elementary and secondary curricula with engineering design can attract underrepresented populations, such as minorities and females, to engineering as a profession. This paper describes a new and innovative engineering design curriculum, under development in the Austin Independent School District (AISD) in Austin, TX. The philosophic goals upon which the curriculum is based include: integrating the design problem-solving process into elementary schools, demonstrating the relationship of technical concepts to daily life, availing teachers with instructional strategies for teaching applied (as opposed to purely theoretical) science and mathematics, and teaching teamwork skills that are so greatly needed in industry and everyday life. Based on these goals, kindergarten, first grade, and second grade engineering design lessons have been piloted in AISD, in conjunction with a University of Texas program for teacher enhancement and preparation.  相似文献   
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Several countries are considering web-based voting as an alternative to, or a replacement of, traditional voting methods. It is argued that electronic voting could increase voter participation and help strengthen democracy, as e-voting would increase accessibility for large sections of the population, particularly with regard to groups that previously have experienced difficulties with the traditional voting setup. With a focus on usability and accessibility, this paper reports on a study evaluating several electronic voting prototypes in Norway, involving technical aspects as well as expert evaluation and user testing in the field, with users from a wide range of disabled user groups participating in the study. Technical testing regarding accessibility standard compliance, testing with the personas method and user testing revealed that many rather basic universal design principles were either not fully understood or not prioritized for implementation by the solution providers. However, despite various accessibility difficulties, the participants generally showed a positive attitude towards web-based elections. Through the findings of this study, the authors highlight factors that are important to consider in the development and testing of web-based voting systems.  相似文献   
10.
Preeclampsia (PE) is characterized by the onset of hypertension (≥140/90 mmHg) and presence of proteinuria (>300 mg/L/24 h urine) or other maternal organ dysfunctions. During human PE, renal injuries have been observed. Some studies suggest that women with PE diagnosis have an increased risk to develop renal diseases later in life. However, in human studies PE as a single cause of this development cannot be investigated. Here, we aimed to investigate the effect of PE on postpartum renal damage in an established transgenic PE rat model. Female rats harboring the human-angiotensinogen gene develop a preeclamptic phenotype after mating with male rats harboring the human-renin gene, but are normotensive before and after pregnancy. During pregnancy PE rats developed mild tubular and glomerular changes assessed by histologic analysis, increased gene expression of renal damage markers such as kidney injury marker 1 and connective-tissue growth factor, and albuminuria compared to female wild-type rats (WT). However, four weeks postpartum, most PE-related renal pathologies were absent, including albuminuria and elevated biomarker expression. Only mild enlargement of the glomerular tuft could be detected. Overall, the glomerular and tubular function were affected during pregnancy in the transgenic PE rat. However, almost all these pathologies observed during PE recovered postpartum.  相似文献   
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