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61.
Amartya Bhattacharjee Ryan C. Hurley Lori Graham-Brady 《Journal of the American Ceramic Society》2022,105(5):3062-3080
The paper presents a numerical model to study the transition of brittle materials from a cracked solid to a granular medium under impact loading. The model addresses competitive crack coalescence in the transition regime and provides insight into the onset of comminution and the initial conditions for subsequent granular flow. Crack statistics obtained from initial flaws using a wing crack growth-based damage model have been used to discretely model elliptical cracks in three dimensions. These discrete cracks are either generated randomly in space or with a constraint that minimizes the intersection between neighboring cracks. These cracks are then allowed to coalesce with nearby cracks along with favorable directions and the output fragment statistics are predicted. A simple statistical model is proposed that suggests a transition criterion resembling the one obtained from the numerical model. Initial fragments are power-law distributed similarly to experimental observations and particle-based models. A generalized form of a microstructure-dependent granular transition criterion based on a threshold measure of crack lengths has been proposed. This model can be implemented in numerical codes to activate granular physics and calibrate the initial conditions of granular flow, such as fragment size and morphology. 相似文献
62.
Magrans-Courtney T Wilborn C Rasmussen C Ferreira M Greenwood L Campbell B Kerksick CM Nassar E Li R Iosia M Cooke M Dugan K Willoughby D Soliah L Kreider RB 《Journal of the International Society of Sports Nutrition》2011,8(1):8-17
Background
The purpose of this study was to determine whether sedentary obese women with knee OA initiating an exercise and weight loss program may experience more beneficial changes in body composition, functional capacity, and/or markers of health following a higher protein diet compared to a higher carbohydrate diet with or without GCM supplementation.Methods
Thirty sedentary women (54 ± 9 yrs, 163 ± 6 cm, 88.6 ± 13 kg, 46.1 ± 3% fat, 33.3 ± 5 kg/m2) with clinically diagnosed knee OA participated in a 14-week exercise and weight loss program. Participants followed an isoenergenic low fat higher carbohydrate (HC) or higher protein (HP) diet while participating in a supervised 30-minute circuit resistance-training program three times per week for 14-weeks. In a randomized and double blind manner, participants ingested supplements containing 1,500 mg/d of glucosamine (as d-glucosamine HCL), 1,200 mg/d of chondroitin sulfate (from chondroitin sulfate sodium), and 900 mg/d of methylsulfonylmethane or a placebo. At 0, 10, and 14-weeks, participants completed a battery of assessments. Data were analyzed by MANOVA with repeated measures.Results
Participants in both groups experienced significant reductions in body mass (-2.4 ± 3%), fat mass (-6.0 ± 6%), and body fat (-3.5 ± 4%) with no significant changes in fat free mass or resting energy expenditure. Perception of knee pain (-49 ± 39%) and knee stiffness (-42 ± 37%) was decreased while maximal strength (12%), muscular endurance (20%), balance indices (7% to 20%), lipid levels (-8% to -12%), homeostasis model assessment for estimating insulin resistance (-17%), leptin (-30%), and measures of physical functioning (59%), vitality (120%), and social function (66%) were improved in both groups with no differences among groups. Functional aerobic capacity was increased to a greater degree for those in the HP and GCM groups while there were some trends suggesting that supplementation affected perceptions of knee pain (p < 0.08).Conclusions
Circuit style resistance-training and weight loss improved functional capacity in women with knee OA. The type of diet and dietary supplementation of GCM provided marginal additive benefits.Trial Registration
ClinicalTrials.gov: NCT01271218 相似文献63.
Kennedy LC Bear AS Young JK Lewinski NA Kim J Foster AE Drezek RA 《Nanoscale research letters》2011,6(1):283
Gold nanoparticle-mediated photothermal therapy (PTT) has shown great potential for the treatment of cancer in mouse studies
and is now being evaluated in clinical trials. For this therapy, gold nanoparticles (AuNPs) are injected intravenously and
are allowed to accumulate within the tumor via the enhanced permeability and retention (EPR) effect. The tumor is then irradiated
with a near infrared laser, whose energy is absorbed by the AuNPs and translated into heat. While reliance on the EPR effect
for tumor targeting has proven adequate for vascularized tumors in small animal models, the efficiency and specificity of
tumor delivery in vivo, particularly in tumors with poor blood supply, has proven challenging. In this study, we examine whether human T cells can
be used as cellular delivery vehicles for AuNP transport into tumors. We first demonstrate that T cells can be efficiently
loaded with 45 nm gold colloid nanoparticles without affecting viability or function (e.g. migration and cytokine production).
Using a human tumor xenograft mouse model, we next demonstrate that AuNP-loaded T cells retain their capacity to migrate to
tumor sites in vivo. In addition, the efficiency of AuNP delivery to tumors in vivo is increased by more than four-fold compared to injection of free PEGylated AuNPs and the use of the T cell delivery system
also dramatically alters the overall nanoparticle biodistribution. Thus, the use of T cell chaperones for AuNP delivery could
enhance the efficacy of nanoparticle-based therapies and imaging applications by increasing AuNP tumor accumulation. 相似文献
64.
Influence of the nanofiber dimensions on the properties of nanocellulose/poly(vinyl alcohol) aerogels 下载免费PDF全文
Silvana Mueller Janak Sapkota Apiradee Nicharat Tanja Zimmermann Philippe Tingaut Christoph Weder E. Johan Foster 《应用聚合物科学杂志》2015,132(13)
The investigation of aerogels made from cellulose nanofibers and poly(vinyl alcohol) (PVOH) as a polymeric binder is reported. Aerogels based on different nanocellulose types were studied to investigate the influence of the nanocellulose dimensions and their rigidity on the morphology and mechanical properties of the resulting aerogels. Thus, cellulose nanocrystals (CNCs) with low (10), medium (25), and high (80) aspect ratios, isolated from cotton, banana plants, and tunicates, respectively, microfibrillated cellulose (MFC) and microcrystalline cellulose (MCC) were dispersed in aqueous PVOH solutions and aerogels were prepared by freeze‐drying. In addition to the cellulose type, the PVOH‐ and the CNC‐concentration as well as the freeze‐drying conditions were varied, and the materials were optionally cross‐linked by an annealing step or the use of a chemical cross‐linker. The data reveal that at low PVOH content, rigid, high‐aspect ratio CNCs isolated from tunicates afford aerogels that show the least amount of shrinking upon freeze‐drying and display the best mechanical properties. However, with increasing concentration of PVOH or upon introduction of a chemical cross‐linker the differences between materials made from different nanocellulose types decrease. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41740. 相似文献
65.
The fabrication of nanocomposites of polyamide 12 (PA12) and cellulose nanocrystals (CNCs) isolated from cotton and tunicates is reported. Through a comparative study that involved solution‐cast (SC) and melt‐processed materials, it was shown that PA12/CNC nanocomposites can be prepared in a process that appears to be readily scalable to an industrial level. The results demonstrate that CNCs isolated from the biomass by phosphoric acid hydrolysis display both a sufficiently high thermal stability to permit melt processing with PA12, and a high compatibility with this polymer to allow the formation of nanocomposites in which the CNCs are well dispersed. Thus, PA12/CNC nanocomposites prepared by melt‐mixing the two components in a co‐rotating roller blade mixer and subsequent compression molding display mechanical properties that are comparable to those of SC reference materials. Young's modulus and maximum stress could be doubled in comparison to the neat PA12 by introduction of 10% (CNCs from tunicates) or 15% w/w (CNCs from cotton) CNCs. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42752. 相似文献
66.
Nantaprapa Nantiyakul Samuel Furse Ian Fisk Timothy J. Foster Gregory Tucker David A. Gray 《Journal of the American Oil Chemists' Society》2012,89(10):1867-1872
We describe a procedure for isolating and purifying oil bodies (OBs) from Oryza sativa bran, and present evidence that strongly suggests a physical association between the OB organelles and several antioxidant phytochemicals (γ-oryzanol and several tocochromanols). This suggestion arises from work showing that despite comprehensive washing steps (9 M urea, water), the majority of the tocotrienols and tocopherols (77 and 73 %, respectively) and oryzanols (91 %) remain integral to the oil bodies, not being released unless the latter are sacrificed. This in turn provides a valuable comparison with similar analyses of tocochromanols in other plant species, as well as indicating that rice bran, normally a waste product from the rice industry, may provide a valuable source of antioxidants as well as protein and unsaturated fat. 相似文献
67.
The hydrodeoxygenation (HDO) of m-cresol is investigated as a model for the HDO of phenolic compounds from lignin pyrolysis. Pt catalysts supported on ??-Al2O3 and SiO2 are effective for the conversion of m-cresol to toluene and methylcyclohexane at 533?K and 0.5?atm H2. Experiments using Pt/??-Al2O3 show that the reaction proceeds by a combination of Pt-catalyzed hydrogenation and acid-catalyzed dehydration reactions. Dehydration of a partially hydrogenated oxygenate intermediate is most likely the dominant reaction pathway to toluene. The acidity of the ??-Al2O3 support was modified by base (K2CO3) and acid (NH4F) treatments, and increasing the number and strength of acid sites was found to increase the rate of HDO. Pt/SiO2 was more active for m-cresol HDO than Pt/Al2O3. The reaction rate on Pt/Al2O3 and Pt/SiO2 decreased after 5?h on stream, but Pt/Al2O3 regained initial reactivity after reductive treatment in H2. 相似文献
68.
R. Colin Carter Sandra W. Jacobson Sharmilah Booley Baheya Najaar Neil C. Dodge Lori J. Bechard Ernesta M. Meintjes Christopher D. Molteno Christopher P. Duggan Joseph L. Jacobson Marjanne Senekal 《Nutrition journal》2018,17(1):108
Background
Although animal and human studies have demonstrated interactions between dietary choline and fetal alcohol spectrum disorders, dietary choline deficiency in pregnancy is common in the US and worldwide. We sought to develop and validate a quantitative food frequency questionnaire (QFFQ) to estimate usual daily choline intake in pregnant mothers.Methods
A panel of nutrition experts developed a Choline-QFFQ food item list, including sources with high choline content and the most commonly consumed choline-containing foods in the target population. A data base for choline content of each item was compiled. For reliability and validity testing in a prospective longitudinal cohort, 123 heavy drinking Cape Coloured pregnant women and 83 abstaining/light-drinking controls were recruited at their first antenatal clinic visit. At 3 prenatal study visits, each gravida was interviewed about alcohol, smoking, and drug use, and administered a 24-hour recall interview and the Choline-QFFQ.Results
Across all visits and assessments, > 78% of heavy drinkers and controls reported choline intake below the Dietary Reference Intakes adequate intake level (450 mg/day). Women reported a decrease in choline intake over time on the QFFQ. Reliability of the QFFQ across visits was good-to-acceptable for 2 of 4 group-level tests and 4 of 5 individual-level tests for both drinkers and controls. When compared with 24-hr recall data, validity of the QFFQ was good-to-acceptable for 3 of 4 individual-level tests and 3 of 5 group-level tests. For controls, validity was good-to-acceptable for all 4 individual-level tests and all 5 group-level tests.Conclusions
To our knowledge, this is the first quantitative choline food frequency screening questionnaire to be developed and validated for use with both heavy and non-drinking pregnant women and the first to be used in the Cape Coloured community in South Africa. Given the high prevalence of inadequate choline intake and the growing evidence that maternal choline supplementation can mitigate some of the adverse effects of prenatal alcohol exposure, this tool may be useful for both research and future clinical outreach programs.69.
A pentane extract of flowers of common milkweed, Asclepias syriaca (Asclepiadaceae), elicited significant orientation from both male and female Culex pipiens in a dual-port flight olfactometer. Analysis of the extract by gas chromatography-mass spectrometry revealed six major constituents in order of relative abundance: benzaldehyde, (E)-β-ocimene, phenylacetaldehyde, benzyl alcohol, nonanal, and (E)-2-nonenal. Although not all were collected from the headspace profile of live flowers, a synthetic blend of these six compounds, when presented to mosquitoes in the same levels and proportions that occur in the extract, elicited a response comparable to the extract. Subtractive behavioral bioassays demonstrated that a three-component blend consisting of benzaldehyde, phenylacetaldehyde, and (E)-2-nonenal was as attractive as the full blend. These findings suggest the potential use of synthetic floral-odor blends for monitoring or control of both male and female disease-vectoring mosquitoes. 相似文献
70.
Pimwalan Techaikool Donraporn Daranarong Jutamas Kongsuk Dheerawan Boonyawan Nursyuhada Haron William S Harley Kyle A Thomson L John R Foster Winita Punyodom 《Polymer International》2017,66(11):1640-1650
Poly[(l ‐lactide)‐co ‐(? ‐caprolactone)] (PLCL) and poly[(l ‐lactide)‐co ‐glycolide] (PLGA) copolymers are widely used in neural guide tissue regeneration. In this research, the surface modification of their hydrophilicity was achieved using plasma treatment. Attachment and proliferation of olfactory ensheathing cells on treated electrospun membranes increased by 26 and 32%, respectively, compared to the untreated PLCL and PLGA counterparts. Cells cultivated on both the PLCL and PLGA membranes showed high viability (>95%) and healthy morphologies with no evidence of cytotoxic effects. Cells grown on treated electrospun fibres displayed significant increases in mitochondrial activity and reductions in membrane leakage when compared to untreated samples. The results suggested that plasma treatment of the surface of the polymers enhanced both cell viability and growth without incurring any cytotoxic effects. © 2017 Society of Chemical Industry 相似文献