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In recent years it has become apparent that the novel properties of nanomaterials may predispose them to a hitherto unknown potential for toxicity. A number of recent toxicological studies of nanomaterials exist, but these appear to be fragmented and often contradictory. Such discrepancies may be, at least in part, due to poor description of the nanomaterial or incomplete characterization, including failure to recognise impurities, surface modifications or other important physicochemical aspects of the nanomaterial. Herew em ake a casef or the importance of good quality, well-characterized nanomaterials for future toxicological studies, combined with reliable synthesis protocols, and we present our efforts to generate such materials. The model system for which we present results is TiO2 nanoparticles, currently used in a variety of commercial products.
We examined the association between life course body weight percentile trajectories and risk for preterm delivery (PTD). Data about women’s weight at birth, age 18, and before pregnancy were obtained by retrospective self-report in a cohort of 1410 black women in metropolitan Detroit. Growth mixture models were used to categorize women with similar weight percentile trajectories across these time points. Log-Poisson models were used to examine the association between the trajectory groups and PTD. Four trajectory groups with different beginning and endpoints of their weight percentiles (high-high, high-low, low-high and low-low) best fit the data. The groups with the highest prevalence of PTD were those that started low (low-high, 21%; low-low, 18%). The low-high group had a higher prevalence of PTD than the high-high trajectory group in unadjusted models (prevalence ratio=1.49 [95% confidence interval (CI) 1.11, 2.00]). The association became not significant after adjusting for maternal age at delivery, income, diabetes and hypertension. When compared with the high-high trajectory group, the low-low trajectory seemed to also have a higher prevalence of PTD after adjusting for maternal age at delivery, income, diabetes and hypertension (prevalence ratio=1.35 [95% CI 1.00, 1.83]). Results suggest that a woman’s risk for PTD is influenced by her body weight trajectory across the life course.
Survey data of 2,538 dairy farmers located in 12 southern states were used to analyze the factors influencing farmers' choice of milk handlers. Results from a qualitative response model indicate that a combination of price and non-price factors contribute to dairy farmers' attitudes toward their milk handlers. Specifically, the decision to change milk handlers was significantly influenced by prices paid and deductions charged. However, non-price factors including field services, friendly personnel, and loyalty to a handler contributed to the longer term affiliation of dairy farmers with their milk handlers.
Nagaland is one of the eight states in the north-eastern region of India, where a considerable diversity exists in cultivated rice. Recent exploration in this tribal-dominated state has resulted in a collection of 130 rice accessions growing under diverse agroecological conditions. The agromorphological characterization data of 124 rice landraces revealed a significant variability in plant architecture and grain morphological and quality traits. Multivariate analyses including principal component analysis (PCA) and cluster analysis were performed to assess the patterns of morphological variation. The PCA extracted 12 components, which explained 75.4% of the total variation for 38 quantitative and qualitative traits. The cluster analysis grouped 124 rice landraces into five clusters, and the number of landraces in each cluster ranged from 1 to 59. The correlations among the traits are discussed, which will be useful in considering traits for genetic improvement in grain yield and quality. The landraces have been conserved in the national genebank for further utilization.
The material characterization toolbox has recently experienced a number of parallel revolutionary advances, foreshadowing a time in the near future when material scientists can quantify material structure evolution across spatial and temporal space simultaneously. This will provide insight to reaction dynamics in four-dimensions, spanning multiple orders of magnitude in both temporal and spatial space. This study presents the authors’ viewpoint on the material characterization field, reviewing its recent past, evaluating its present capabilities, and proposing directions for its future development. Electron microscopy; atom probe tomography; x-ray, neutron and electron tomography; serial sectioning tomography; and diffraction-based analysis methods are reviewed, and opportunities for their future development are highlighted. Advances in surface probe microscopy have been reviewed recently and, therefore, are not included [D.A. Bonnell et al.: Rev. Modern Phys. in Review]. In this study particular attention is paid to studies that have pioneered the synergetic use of multiple techniques to provide complementary views of a single structure or process; several of these studies represent the state-of-the-art in characterization and suggest a trajectory for the continued development of the field. Based on this review, a set of grand challenges for characterization science is identified, including suggestions for instrumentation advances, scientific problems in microstructure analysis, and complex structure evolution problems involving material damage. The future of microstructural characterization is proposed to be one not only where individual techniques are pushed to their limits, but where the community devises strategies of technique synergy to address complex multiscale problems in materials science and engineering.
The theory of particle aspect analysis is extended to the drift wave in the presence of an inhomogeneous magnetic field. The dispersion relation and growth rate of the wave are evaluated and discussed when the magnetic field gradient is directed opposite to the density gradient. The plasma under consideration is assumed to be anisotropic and the effects of temperature anisotropy on the dispersion characteristics and growth rate of the wave are also studied. The dispersion relation and the growth rate are evaluated for the space plasma parameters.
Effect of graded levels of high-glucosinolate mustard (Brassica juncea) meal as substitute of soya-bean meal (SBM) in broiler rabbit diets was studied. Forty weaning rabbits of Soviet Chinchilla and White Giant breed were randomly allocated to one of four experimental diets containing mustard meal (MM) 0, 80, 160 and 245 g/kg. The experiment lasted for 8 weeks. MM had 54.8 mg total glucosinolates (TGLSs) per g dry matter (DM). Diets had TGLS 3.8, 8.4 and 11.98 mg/g DM in 80, 160 and 245 g MM diets, respectively. MM-incorporated diets had higher digestible and linearly (P < 0.01) higher metabolisable energy (ME) content. However, the effect on total tract apparent digestibility of DM, and crude protein was quadratic. Average daily gain (ADG) reduced (P < 0.05) linearly with increasing MM levels in diet, still 80 and 160 g MM diets had similar ADG compared to that of SBM diet. Caecum weight reduced linearly (P < 0.05) with increasing MM levels in diet. The pH of caecal content ranged between 5.85 and 6.19, total N between 1.19 and 1.48 (g per 100 g) and total volatile fatty acids between 4.7 and 5.8 mmol per 100 g, and they were not statistically different. NH3-N ranged between 31.2 and 39.0 mg per 100 ml, and reduced linearly (P < 0.05) while trichloroacetic acid-precipitable nitrogen increased linearly (P < 0.01, ranged between 114 and 247 mg per 100 ml) with increasing MM levels in diet. Blood haemoglobin, packed cell volume and lymphocytes were higher (quadratic effects, P < 0.05) on 245 MM diet, whereas white blood cell count reduced linearly (P < 0.01). Serum aspartate aminotransferase increased linearly (P < 0.01) while alanine aminotransferase and alkaline phosphatase activity, protein, erythrocytes sedimentation rate and red blood cell counts were not affected by MM. Serum Cu, Na and K content increased linearly (P < 0.05) with increasing MM levels. Liver Cu concentration showed quadratic (P < 0.05) increase. Rabbits tolerated 8.4 mg TGLS per g diet (160 g MM per kg) during active growth without any apparent effect on health and growth. It is concluded that MM can replace up to 66% SBM protein in rabbit feeding, whereas complete replacement of SBM with MM reduced feed intake and ADG by 23% and 13%, respectively. Further studies are required to confirm these inclusion levels and glucosinolate tolerance of rabbits.
The development of transgenic crops as production platforms for biogenic agents will largely depend on the success of efforts to confine the genes and their expressed proteins in field environments. We have used quantitative exposure assessment to evaluate how management practices affect materials escape due to outcrossing by pollen flow or grain loss during harvest operations. Specifically, we study the use of maize to produce biogenic agents within field-confined systems. Decision trees representing simplified schemes of fully conforming (designed to comply with current regulatory standards for field confined trials), partially conforming, and non-conforming management practices were developed. Exemplifying assumptions and published data for conformance and material fate probabilities were used in Monte Carlo simulations to forecast materials escape by pollen outcrossing and harvest operations from a 1 ha source field. Deterministic analyses showed fully conforming confinement management restricted materials loss to low levels (for this example, outcrossing produced <1 in 106 kernels in receptor fields). The corresponding high-end (90th percentile) probabilistic result was 16- and 4333-fold higher (relative to deterministic outcrossing = 1) for outcrossing and harvest loss, respectively. For partially conforming practice, high-end outcrossing ranged from 100- to >15 000-fold over the base result in receptor fields, and harvest loss was >10 000-fold over the base result. For non-conforming practice, high-end outcrossing produced >15 000-fold greater kernels in receptor fields and high-end harvest loss was at least 19 000-fold greater. Deterministic estimates of off-field loss by machine transfer are as much as 30 000-fold higher for non-conforming operations relative to the base case of pollen outcrossing. Better knowledge of failure frequencies for confinement management practices, improved physical models of materials flows, refined analysis of confinement loss probabilities using quantitative tools, and decision analysis to improve and audit management system performance are all needed to extend understanding of confinement integrity beyond the exemplifying case used here.
Electrodeposited Ni and Ni-diamond composite layers were used as diffusion barriers for Fe to facilitate the diamond growth on stainless steel substrates. Raman spectroscopy and scanning electron microscopy show the formation of good quality diamond crystallites by chemical vapor deposition. X-ray diffraction results indicate that the expansion of Ni unit cell has taken place due to the formation of the Ni–C solid solution. This observation is also well supported by x-ray photoelectron spectroscopy studies. The lattice constant of the expanded Ni unit cell matches closely with the diamond, and this may be helpful in explaining the epitaxial growth of diamond on single-crystal Ni observed by others.
In this study, trifluoroiodomethane (CF3I), a non-global-warming gas, has been investigated as a substitute for typical PFC's currently used in wafer patterning and CVD chamber cleaning processes. Dielectric films consisting of plasma enhanced chemically vapor deposited silicon dioxide and silicon nitride were comparatively etched in CF3I and C2F6/O2 plasma environments. The etch rate of these films was ascertained as a function of applied rf power, etchant gas flow rate, reaction chamber pressure, and CF3I: O2 ratio. Destruction efficiencies of CF3I at different processing parameters were evaluated. Depending on the flow rate, rf power, and chamber pressure, utilization efficiency of CF3I varied from as low as 10% to as high as 68%. CF4, C2F6, COF2, and CO2 were the predominant by-products found in the exhaust stream; however, their concentrations were very low compared to the traditional process employing C2F6/O2 mixtures.
Sorghum is a multipurpose crop where all parts of the plant are used for human food, animal food, fuel and fabrication. In comparison to other cereal crops it requires little water and it is tolerant to poor soils and adverse climatic conditions. It is one of the most widely grown crops in India particularly in semi-arid and rain-fed regions where the potential for crop and livestock production is limited by the availability of water. During the kharif season (July to October), it occupies about 10 million ha of land and produces a large quantity of stover which is given to farm livestock. The rabi season crop (November to February) occupies about 6 million ha of land and is mainly dependent upon residual moisture in the soil and provides both grain and forage. The economic value of sorghum stover as fodder sometimes exceeds that of the grain because seasonal shortage of food is an acute problem during the dry season. Much effort has been expended on improving sorghum varieties (Burton, 1973; Gupta et al., 1976; Dongi and Paroda, 1978), mostly directed towards increasing the yield. Pederson et al. (1982) compared the quality and agronomic traits of 49 forage sorghum hybrids and suggested that the most rapid way to improve the quality of forage sorghum would be to improve its in vitro dry-matter (DM) digestibility. There are several new strains of sorghum which have been improved in terms of agronomic characters but there is little information on the nutritional quality of their stovers. Therefore the objective of this study was to evaluate the stovers of several new sorghum strains in terms of chemical composition, in sacco DM disappearance (DMD) and their silage quality.
This study explored the relation of level of socio-economic development to the course of non-affective psychosis, by extending the analysis of urban/rural differences in course in Chandigarh, India.
The proportion of ‘best outcome cases between urban (n=110) and rural (n=50) catchment areas were compared at two-year follow-up, separately for CATEGO S+ and non-S+ schizophrenia.
The proportion of subjects with ‘best outcome’ ratings at the urban and rural sites, respectively, was similar for CATEGO S+ schizophrenia (29 v. 29%), but significantly different for non-S+ psychosis (26 v. 47%)
The fact that in rural Chandigarh, psychoses have a more favourable course than in the urban area may be explained in large part by psychoses distinct from ‘nuclear’ schizophrenia.
This paper is a retrospective study of 15 patients with parapharyngeal neurofibromas operated over a six year period. No patient presented with a neurological deficit. CT scans revealed a well encapsulated moderately enhancing mass in ten cases. The tumour was removed by a transcervical approach in ten cases while in five a cervical-transpharyngeal route with mandibulotomy was used; in three of the latter group the tumour was retropharyngeal. In two cases a recurrence was successfully excised. It was realized that a mandibulotomy was required when the internal carotid was displaced medially, or if the tumour extended to the base of skull or when its vertical diameter exceeded 8 cm.
Chemical reaction can occur at the fiber/matrix interface of intermetallic matrix composites, leading to a degradation of mechanical properties. Fe–40Al matrix composites were fabricated using SiC, B, W, Mo-base, and Al2O3 fibers. Composite samples were heat treated up to 1500 K to study the reaction kinetics, and reaction rates were determined from reaction zone thickness measurements. The Al2O3 and W fibers were found to be compatible with the Fe–40Al matrix, while the Mo-based fibers reacted moderately and the B and SiC fibers reacted severely. Experimental results are compared to theoretical thermodynamic predictions.
The Didwana region has preserved lower palaeolithic artefacts in primary and semi-primary contexts. On the basis of geological stratigraphy of aeolian and playa sediments, artefacts occurring in a stratified context have been dated to the Middle Pleistocene. In order to work out technological evolutionary trends of the acheulian culture in this region, 301 handaxes from 10 localities have been studied following Roe's methodology, with some additional attributes. Some differences in size, shape and refinement are apparent between the collections. Statistics, diagrams, factor and cluster analyses suggest a technological evolution within the assemblages and therefore indicate the chronology of the sites. Compared with those of other known Indian sites, these handaxes may correspond to cultural stages ranging between early acheulian and very late acheulian or even early middle palaeolithic.
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