978 resultados para 13077-065


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对沈阳市郊区43对蔬菜保护地与相邻的露地土壤中交换性Ca、Mg含量状况及Ca/Mg比值进行对比研究的结果表明:与露地土壤相比,保护地土壤交换性Ca平均含量下降6.38%,Ca/Mg比值下降10.34%,交换性Mg平均含量上升4.74%。蔬菜保护地及露地土壤的Ca/Mg比值与交换性Ca含量呈极显著相关(r分别为0.721和0.757,n=43,P<0.01),Ca/Mg比值与交换性Mg含量无显著相关性(r分别为-0.065和-0.117,n=43)。交换性Ca含量下降的主要原因是随蔬菜输出到系统外的Ca量相对较多、含钙肥料施用量减少及土壤pH下降;交换性Mg含量上升的主要原因是土壤中适宜的pH范围(5.0~6.5)有利于Mg以交换性形态存在,土壤中高浓度的Ca2+、K+、NH+4抑制了蔬菜对Mg2+的选择性吸收。

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Background The application of polyethylenimine (PEI) in gene delivery has been severely limited by significant cytotoxicity that results from a nondegradable methylene backbone and high cationic charge density. It is therefore necessary to develop novel biodegradable PEI derivates for low-toxic, highly efficient gene delivery.Methods A series of novel cationic copolymers with various charge density were designed and synthesized by grafting different kinds of oligoethylenimine (OEI) onto a determinate multi-armed poly(L-glutamic acid) backbone. The molecular structures of multi-armed poly(L-glutamic acid)-graft-OEI (MP-g-OEI) copolymers were characterized using nuclear magnetic resonance, viscosimetry and gel permeation chromatography. Moreover, the MP-g-OEI/DNA complexes were measured by a gel retardation assay, dynamic light scattering and atomic force microscopy to determine DNA binding ability, particle size, zeta potential, complex formation and shape, respectively. MP-g-OEI copolymers were also evaluated in Chinese hamster ovary and human embryonic kidney-293 cells for their cytotoxicity and transfection efficiency.

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The crystal structure of the title compound has been determined from single crystal X-ray diffraction. The complex crystallizes in the triclinic space group P1 with Z=2. Lattice parameters are: a = 0.7296(1), b = 1.0110(3), c = 1.2814(4) nm; alpha = 90.84(2), beta = 101.17(2), gamma = 92.52(2)-degrees. Intensity data were collected on a Nicolet R3M/E four-circle diffractometer using MoK alpha (lambda = 0.071073 nm) radiation. The structure was solved by Patterson and Fourier techniques and refined by least-squares techniques to R = 0.065. The structure of the complex consists of tetrahedral ZnCl42- anions which form a two-dimensional sheets. Tetrahedral ZnCl42- anions are sandwiched between two hydrocarbon layers which consist of [NH3(CH2)10NH3]2+ cations. Each [NH3(CH2)10NH3]2+ group is in a gauche bond between C atoms near NH3 polar heads.

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在氮限制型富营养化湖泊中,沉积多磷酸盐(Poly-P)可以用来示踪营养盐磷的输入和湖泊的富营养化过程。太湖是一个典型的磷限制型富营养化湖泊,通过对太湖表层沉积物中总有机碳(TOC)、总氮(TN)、总磷(TP)、氢氧化钠可提取磷(NaOH-P)以及Poly-P 的提取分析,初步探讨了太湖营养盐磷输入的历史记录,并揭示了该湖Poly-P 的主要来源和保存机制。太湖Poly-P 的质量浓度较低,变化范围为0.004~0.065 mg·g-1。NaOH-P 占TP 组成的22%,是太湖沉积物总磷的主要组成部分之一。结果显示,在湖泊水体藻类生物量较大和NaOH-P 是沉积物TP 重要组成部分的磷限制型湖泊中,Poly-P 也是沉积物磷汇组成的一个重要部分,同时还是一个可以反映由人为磷输入增大导致湖泊富营养化程度加剧的敏感指标。

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RESUMO: Com o objetivo de avaliar o desempenho agronômico de genótipos de girassol nas condições edafoclimáticas do primeiro semestre de 2015 na Chapada do Araripe, instalou-se um experimento na Estação Experimental do Instituto Agronômico de Pernambuco (IPA), no município de Araripina, Estado de Pernambuco. O delineamento foi o de blocos ao acaso, com quatro repetições e 13 tratamentos, correspondendo aos genótipos de girassol: M734, NTC 90, BRS G43, BRS G44, BRS G45, BRS G46, SYN 065, HLA 2013, HLA 2014, HLA 2015, HLA 2016, HLA 2017 e SYN 045. Avaliaram-se as seguintes características: sobrevivência final, floração inicial, maturação fisiológica, altura média do capítulo, peso de 1000 aquênios, diâmetro médio dos capítulos, produção final de aquênios, curvatura do capítulo e plantas acamadas, quebradas e atacadas por pássaros. Os genótipos apresentaram diferenças morfoagronômicas quando cultivados no primeiro semestre em condições edafoclimáticas da região do Araripe, com exceção da variável sobrevivência. O genótipo NTC 90 alcançou o maior peso de aquênios. Todos os genótipos, exceto HLA 2015, apresentaram elevado rendimento de grãos. Os caracteres plantas acamadas, quebradas, atacadas por pássaros ou a curvatura do capítulo não foram relacionadas às diferentes cultivares. ABSTRACT: The study aimed to evaluate the agronomic performance of different sunflower genotypes in edaphoclimatic conditions of Araripe region in the first semester of 2015. The experiment was established at the Experimental Station of Instituto Agronômico de Pernambuco (IPA), Araripina, Pernambuco, Brazil. Experimental design was a randomized blocks with thirteen treatments, corresponding to the sunflower genotypes: M734, NTC 90, BRS G43, BRS G44, BRS G45, BRS G46, SYN 065, HLA 2013, HLA 2014, HLA 2015, HLA 2016, HLA 2017 e SYN 045, with four replicates. The following characteristics were evaluated: final survival, early flowering, physiological maturity, average plant height, weight of 1,000 seeds, average flower diameter, final seed production, flower head curvature, lodged, broken and damaged by birds plants. The genotypes showed morphoagronomic differences when grown in the first semester of 2015 on edaphoclimatic conditions of the Araripe region, except for the variable survival. The NTC 90 genotype achieved the highest weight of head flower. All genotypes, except HLA 2015 showed high grain yield. The characters lodged, broken and damaged plants by birds or curvature of the head flower were not related to the different cultivars.

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RESUMO:Com o objetivo de avaliar o comportamento agronômico de genótipos de girassol no Cerrado do Distrito Federal, foram conduzidos ensaios na safrinha dos anos de 2014 e 2015, na estação experimental da Embrapa Cerrados, Planaltina, DF. O delineamento experimental foi de blocos ao acaso com quatro repetições, e foram avaliados 12 genótipos de girassol: HLA 2015, NTC 90, SYN 065, M734, BRS G44, HLA 2014, BRS G45, BRS G43, HLA 2013, HLA 2017, BRS G46, HLA 2016. As características avaliadas foram rendimento de grãos, tamanho do capitulo, peso de mil aquênios, altura de plantas e dias de floração inicial. Diferenças significativas foram encontradas para as características avaliadas. Os genótipos que se destacaram em relação ao rendimento de grãos foram HLA 2014 (3.161 kg ha-1) e a testemunha M743 (3.212 kg ha-1). Além disso, o ensaio do ano 2014 apresentou uma média de rendimento maior (2.829 kg ha-1) e mais precoces (63,10 dias) em relação a 2015. O trabalho permitiu a identificação de materiais promissores para exploração em programas de melhoramento genético. ABSTRACT: Aiming the evaluation on agronomic behavior of sunflower genotypes in the Brazilian savannah, experiments were carried on in the second crop of 2014 and 2015 at Centro de Pesquisa Agropecuária dos Cerrados (Embrapa), Planaltina, DF. A complete randomized block design was used with four replications and 12 genotypes of sunflower were analyzed: HLA 2015, NTC 90, SYN 065, M734, BRS G44, HLA 2014, BRS G45, BRS G43, HLA 2013, HLA 2017, BRS G46, HLA 2016.The evaluated characteristics were grain yield, head, weight thousand achenes, plant height, and flowering time. Significant differences were found in all evaluated characteristics. The genotypes that stood out in seed yield were HLA 2014 (3161 kg ha-1) and M743 (3212 kg ha-1). Besides, the 2014 experiment presented a seed yield average higher (2829 kg ha-1), and earlier flowering (63,10 days) when compared to 2015 experiment. This study allowed the identification of promising materials to explore in breeding programs.

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PURPOSE: Mammography is known to be one of the most difficult radiographic exams to interpret. Mammography has important limitations, including the superposition of normal tissue that can obscure a mass, chance alignment of normal tissue to mimic a true lesion and the inability to derive volumetric information. It has been shown that stereomammography can overcome these deficiencies by showing that layers of normal tissue lay at different depths. If standard stereomammography (i.e., a single stereoscopic pair consisting of two projection images) can significantly improve lesion detection, how will multiview stereoscopy (MVS), where many projection images are used, compare to mammography? The aim of this study was to assess the relative performance of MVS compared to mammography for breast mass detection. METHODS: The MVS image sets consisted of the 25 raw projection images acquired over an arc of approximately 45 degrees using a Siemens prototype breast tomosynthesis system. The mammograms were acquired using a commercial Siemens FFDM system. The raw data were taken from both of these systems for 27 cases and realistic simulated mass lesions were added to duplicates of the 27 images at the same local contrast. The images with lesions (27 mammography and 27 MVS) and the images without lesions (27 mammography and 27 MVS) were then postprocessed to provide comparable and representative image appearance across the two modalities. All 108 image sets were shown to five full-time breast imaging radiologists in random order on a state-of-the-art stereoscopic display. The observers were asked to give a confidence rating for each image (0 for lesion definitely not present, 100 for lesion definitely present). The ratings were then compiled and processed using ROC and variance analysis. RESULTS: The mean AUC for the five observers was 0.614 +/- 0.055 for mammography and 0.778 +/- 0.052 for multiview stereoscopy. The difference of 0.164 +/- 0.065 was statistically significant with a p-value of 0.0148. CONCLUSIONS: The differences in the AUCs and the p-value suggest that multiview stereoscopy has a statistically significant advantage over mammography in the detection of simulated breast masses. This highlights the dominance of anatomical noise compared to quantum noise for breast mass detection. It also shows that significant lesion detection can be achieved with MVS without any of the artifacts associated with tomosynthesis.

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Background: A number of factors are known to influence food preferences and acceptability of new products. These include their sensory characteristics and strong, innate neural influences. In designing foods for any target group, it is important to consider intrinsic and extrinsic characteristics which may contribute to palatability, and acceptability of foods. Objective: To assess age and gender influences on sensory perceptions of novel low cost nutrient-rich food products developed using traditional Ghanaian food ingredients. Materials and Methods: In this study, a range of food products were developed from Ghanaian traditional food sources using the Food Multimix (FMM) concept. These products were subjected to sensory evaluation to assess the role of sensory perception on their acceptability among different target age groups across the life cycle (aged 11-68 years olds) and to ascertain any possible influences of gender on preference and choice. Variables including taste, odour, texture, flavour and appearance were tested and the results captured on a Likert scale and scores of likeness and acceptability analysed. Multivariate analyses were used to develop prediction models for targeted recipe development for different target groups. Multiple factor analysis of variance (ANOVA) and logistic linear regression were employed to test the strength of acceptability and to ascertain age and gender influences on product preference. Results: The results showed a positive trend in acceptability (r = 0.602) which tended towards statistical significance (p = 0.065) with very high product favourability rating (91% acceptability; P=0.005). However, age [odds ratios=1.44 (11-15 years old) odds ratios=2.01 (18-68 years old) and gender (P=0.000)] were major influences on product preference with children and females (irrespective of age) showing clear preferences or dislike of products containing certain particular ingredients. Conclusion: These findings are potentially useful in planning recipes for feeding interventions involving different vulnerable and target groups.

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The biogeochemical cycle of zinc (Zn) in the South Atlantic, at 40°S, was investigated as part of the UK GEOTRACES program. To date there is little understanding of the supply of Zn, an essential requirement for phytoplankton growth, to this highly productive region. Vertical Zn profiles displayed nutrient-like distributions with distinct gradients associated with the watermasses present. Surface Zn concentrations are among the lowest reported for theworld’s oceans (<50 pM). A strong Zn-Si linear relationshipwas observed (Zn (nM)= 0.065 Si (μM), r2=0.97, n = 460). Our results suggest that the use of a global Zn-Si relationship would lead to an underestimation of dissolved Zn in deeper waters of the South Atlantic. By utilizing Si* and a new tracer Zn* our data indicate that the preferential removal of Zn in the Southern Ocean prevented a direct return path for dissolved Zn to the surface waters of the South Atlantic at 40°S and potentially the thermocline waters of the South Atlantic subtropical gyre. The importance of Zn for phytoplankton growth was evaluated using the Zn-soluble reactive phosphorus (SRP) relationship. We hypothesize that the low Zn concentrations in the South Atlantic may select for phytoplankton cells with a lower Zn requirement. In addition, a much deeper kink at ~ 500m in the Zn:SRP ratio was observed compared to other oceanic regions.

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Although the bactericidal effect of copper has been known for centuries, there is a current resurgence of interest in the use of this element as an antimicrobial agent. During this study the use of dendritic copper microparticles embedded in an alginate matrix as a rapid method for the deactivation of Escherichia coli ATCC 11775 was investigated. The copper/alginate produced a decrease in the minimum inhibitory concentration from free copper powder dispersed in the media from 0.25 to 0.065 mg/ml. Beads loaded with 4% Cu deactivated 99.97% of bacteria after 90 minutes, compared to a 44.2% reduction in viability in the equivalent free copper powder treatment. There was no observed loss in the efficacy of this method with increasing bacterial loading up to 10(6) cells/ml, however only 88.2% of E. coli were deactivated after 90 minutes at a loading of 10(8) cells/ml. The efficacy of this method was highly dependent on the oxygen content of the media, with a 4.01% increase in viable bacteria observed under anoxic conditions compared to a >99% reduction in bacterial viability in oxygen tensions above 50% of saturation. Scanning electron micrographs (SEM) of the beads indicated that the dendritic copper particles sit as discrete clusters within a layered alginate matrix, and that the external surface of the beads has a scale-like appearance with dendritic copper particles extruding. E. coli cells visualised using SEM indicated a loss of cellular integrity upon Cu bead treatment with obvious visible blebbing. This study indicates the use of microscale dendritic particles of Cu embedded in an alginate matrix to effectively deactivate E. coli cells and opens the possibility of their application within effective water treatment processes, especially in high particulate waste streams where conventional methods, such as UV treatment or chlorination, are ineffective or inappropriate.

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Coherent anti-Stokes Raman scattering (CARS) microscopy has developed rapidly and is opening the door to new types of experiments. This work describes the development of new laser sources for CARS microscopy and their use for different applications. It is specifically focused on multimodal nonlinear optical microscopy—the simultaneous combination of different imaging techniques. This allows us to address a diverse range of applications, such as the study of biomaterials, fluid inclusions, atherosclerosis, hepatitis C infection in cells, and ice formation in cells. For these applications new laser sources are developed that allow for practical multimodal imaging. For example, it is shown that using a single Ti:sapphire oscillator with a photonic crystal fiber, it is possible to develop a versatile multimodal imaging system using optimally chirped laser pulses. This system can perform simultaneous two photon excited fluorescence, second harmonic generation, and CARS microscopy. The versatility of the system is further demonstrated by showing that it is possible to probe different Raman modes using CARS microscopy simply by changing a time delay between the excitation beams. Using optimally chirped pulses also enables further simplification of the laser system required by using a single fiber laser combined with nonlinear optical fibers to perform effective multimodal imaging. While these sources are useful for practical multimodal imaging, it is believed that for further improvements in CARS microscopy sensitivity, new excitation schemes are necessary. This has led to the design of a new, high power, extended cavity oscillator that should be capable of implementing new excitation schemes for CARS microscopy as well as other techniques. Our interest in multimodal imaging has led us to other areas of research as well. For example, a fiber-coupling scheme for signal collection in the forward direction is demonstrated that allows for fluorescence lifetime imaging without significant temporal distortion. Also highlighted is an imaging artifact that is unique to CARS microscopy that can alter image interpretation, especially when using multimodal imaging. By combining expertise in nonlinear optics, laser development, fiber optics, and microscopy, we have developed systems and techniques that will be of benefit for multimodal CARS microscopy.

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Ensis siliqua is regarded as an increasingly valuable fishery resource with potential for commercial aquaculture in many European countries. The genetic variation of this razor clam was analysed by randomly amplified polymorphic DNA (RAPD) in six populations from Spain, Portugal and Ireland. Out of the 40 primers tested, five were chosen to assess genetic variation. A total of 61 RAPD loci were developed ranging in size from 400 to 2000 bp. The percentages of polymorphic loci, the allele effective number and the genetic diversity were comparable among populations, and demonstrated a high level of genetic variability. The values of Nei's genetic distance were small among the Spanish and Portuguese populations (0.051-0.065), and high between these and the Irish populations. Cluster and principal coordinate analyses supported these findings. A mantel test performed between geographic and genetic distance matrices showed a significant correlation (r=0.84, P

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Job satisfaction can be conceptualized as a function of situational conditions, personal characteristics, and interactions between both groups of variables. The authors compared the relative predictive power of these determinants in 3 samples of professionals (total N = 1,065). Perceived job characteristics (qualification possibilities, social support, stress, autonomy, participatory leadership) uniquely explained 7-22% of the variance in job satisfaction, and dispositional factors (Big Five, occupational self-efficacy, work centrality, mastery goals) uniquely explained 8-12% of the variance. Dispositional influences were partially mediated by perceived job characteristics. Interactions between situational and dispositional factors were of little significance. The authors concluded that perceived job characteristics (especially autonomy and participatory leadership) are important determinants of job satisfaction, and neuroticism is an important determinant as well. Highly educated professionals job satisfaction also seems to be driven by qualification possibilities.

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We conducted a genome-wide association study testing single nucleotide polymorphisms (SNPs) and copy number variants (CNVs) for association with early-onset myocardial infarction in 2,967 cases and 3,075 controls. We carried out replication in an independent sample with an effective sample size of up to 19,492. SNPs at nine loci reached genome-wide significance: three are newly identified (21q22 near MRPS6-SLC5A3-KCNE2, 6p24 in PHACTR1 and 2q33 in WDR12) and six replicated prior observations1-4 (9p21, 1p13 near CELSR2-PSRC1-SORT1, 10q11 near CXCL12, 1q41 in MIA3, 19p13 near LDLR and 1p32 near PCSK9). We tested 554 common copy number polymorphisms (>1% allele frequency) and none met the pre-specified threshold for replication (P < 10-3). We identified 8,065 rare CNVs but did not detect a greater CNV burden in cases compared to controls, in genes compared to the genome as a whole, or at any individual locus. SNPs at nine loci were reproducibly associated with myocardial infarction, but tests of common and rare CNVs failed to identify additional associations with myocardial infarction risk.