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11.
Membrane hydrophilicity influences the transport of water through the membrane in osmotically driven separations such as forward osmosis. In this paper, we coated the polysulfone support layer of two types of commercially available reverse osmosis membranes (brackish water and seawater) with hydrophilic polyvinyl alcohol (PVA). The aim of this was to increase the support layer hydrophilicity and, correspondingly, the rate of water transport through the membrane. Previous work with polydopamine coatings of the polysulfone support of reverse osmosis membranes has yielded promising results. In this work, we explore more readily available materials. Specifically, we studied the effects of two different PVA crosslinking agents – maleic acid and glutaraldehyde – on the resultant membrane properties and osmotic performance. For seawater membranes we found that PVA crosslinked to a limited degree with maleic acid creates a significant improvement in water flux in RO and FO systems, as compared to membranes with PVA crosslinked by glutaraldehyde. However, brackish water membranes did not have comparably significant changes in membrane performance. We conclude that the smaller pores of the brackish water membrane become clogged, and this effect is magnified by the lack of fractional free volume available within PVA that is highly crosslinked with glutaraldehyde. 相似文献
12.
With the recent attention to ‘sitting disease’, health practitioners and scientists are promoting standing in the workplace to decrease sedentary time, despite a high prevalence of low back pain (LBP) development during prolonged standing. The purpose of this study was to assess how a seated break inserted between bouts of prolonged standing would influence LBP development, posture and movement. A total of 20 participants stood for 45 minutes, sat for 15 minutes and repeated this sequence while lumbar and thoracic angles were measured, and LBP visual analogue scale reports were taken. Of the sample, 55% participants reported LBP in standing. A stand to sit ratio of 3:1 did not provide lasting recovery of LBP from standing and pain developers utilised a limited range of their lumbar spine angle and increased thoracic extension, resulting in static postures that caused tissue aggravation that was not resolved after 15 minutes of sitting. Prolonged standing in the workplace has the potential to result in LBP for some workers and alternate ways to reduce sedentary time should be investigated. 相似文献
13.
Rissin DM Fournier DR Piech T Kan CW Campbell TG Song L Chang L Rivnak AJ Patel PP Provuncher GK Ferrell EP Howes SC Pink BA Minnehan KA Wilson DH Duffy DC 《Analytical chemistry》2011,83(6):2279-2285
We report a method for combining the detection of single molecules (digital) and an ensemble of molecules (analog) that is capable of detecting enzyme label from 10(-19) M to 10(-13) M, for use in high sensitivity enzyme-linked immunosorbent assays (ELISA). The approach works by capturing proteins on microscopic beads, labeling the proteins with enzymes using a conventional multistep immunosandwich approach, isolating the beads in an array of 50-femtoliter wells (Single Molecule Array, SiMoA), and detecting bead-associated enzymatic activity using fluorescence imaging. At low concentrations of proteins, when the ratio of enzyme labels to beads is less than ~1.2, beads carry either zero or low numbers of enzymes, and protein concentration is quantified by counting the presence of "on" or "off" beads (digital regime). (1) At higher protein concentrations, each bead typically carries multiple enzyme labels, and the average number of enzyme labels present on each bead is quantified from a measure of the average fluorescence intensity (analog regime). Both the digital and analog concentration ranges are quantified by a common unit, namely, average number of enzyme labels per bead (AEB). By combining digital and analog detection of singulated beads, a linear dynamic range of over 6 orders of magnitude to enzyme label was achieved. Using this approach, an immunoassay for prostate specific antigen (PSA) was developed. The combined digital and analog PSA assay provided linear response over approximately four logs of concentration ([PSA] from 8 fg/mL to 100 pg/mL or 250 aM to 3.3 pM). This approach extends the dynamic range of ELISA from picomolar levels down to subfemtomolar levels in a single measurement. 相似文献
14.
Isaacowitz Derek M.; Toner Kaitlin; Neupert Shevaun D. 《Canadian Metallurgical Quarterly》2009,24(4):989
Older adults show positive preferences in their gaze toward emotional faces, and such preferences appear to be activated when older adults are in bad moods. This suggests that age-related gaze preferences serve a mood regulatory role, but whether they actually function to improve mood over time has yet to be tested. We investigated links between fixation and mood change in younger and older adults, as well as the moderating role of attentional functioning. Age × Fixation × Attentional Functioning interactions emerged such that older adults with better executive functioning were able to resist mood declines by showing positive gaze preferences. Implications for the function of age-related positive gaze preferences are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
15.
Maude Perreault Kaitlin Roke Alaa Badawi Daiva E. Nielsen Salma A. Abdelmagid Ahmed El-Sohemy David W. L. Ma David M. Mutch 《Lipids》2014,49(3):255-263
Inflammation is a recognized risk factor for the development of chronic diseases, such as type 2 diabetes and atherosclerosis. Evidence suggests that individual fatty acids (FA) may have distinct influences on inflammatory processes. The goal of this study was to conduct a cross-sectional analysis to examine the associations between circulating FA and markers of inflammation in a population of young healthy Canadian adults. FA, high-sensitivity C-reactive protein (hsCRP), and cytokines were measured in fasted plasma samples from 965 young adults (22.6 ± 0.1 years). Gas chromatography was used to measure FA. The following cytokines were analyzed with a multiplex assay: regulated upon activation normal T cell expressed and secreted (RANTES/CCL5), interleukin 1-receptor antagonist (IL-1Ra), interferon-γ (IFN-γ), interferon-γ inducible protein 10 (IP-10), and platelet-derived growth factor β (PDGF-ββ). Numerous statistically significant associations (p < 0.05, corrected for multiple testing) were identified between individual FA and markers of inflammation using linear regression. Myristic (14:0), palmitic (16:0), palmitoleic (16:1n-7), and dihomo-γ-linolenic (20:3n-6) acids were positively associated with all markers of inflammation. In contrast, stearic acid (18:0) was inversely associated with hsCRP and RANTES, and linoleic acid (18:2n-6) was inversely associated with hsCRP, RANTES and PDGF-ββ. In conclusion, our results indicate that specific FA are distinctly correlated with various markers of inflammation. Moreover, the findings of this study suggest that FA profiles in young adults may serve as an early indicator for the development of future complications comprising an inflammatory component. 相似文献
16.
Sex Differences in Blood HDL-c,the Total Cholesterol/HDL-c Ratio,and Palmitoleic Acid are Not Associated with Variants in Common Candidate Genes 下载免费PDF全文
Shannon L. Klingel Kaitlin Roke Bertha Hidalgo Stella Aslibekyan Robert J. Straka Ping An Michael A. Province Paul N. Hopkins Donna K. Arnett Jose M. Ordovas Chao-Qiang Lai David M. Mutch 《Lipids》2017,52(12):969-980
Blood lipids are associated with cardiovascular disease (CVD) risk. Moreover, circulating lipid and fatty acid levels vary between men and women, and evidence demonstrates these traits may be influenced by single nucleotide polymorphisms (SNP). Sex-genotype interactions related to blood lipids and fatty acids have been poorly investigated and may help elucidate sex differences in CVD risk. The goal of this study was to investigate if the influence of SNPs previously associated with blood lipids and fatty acids varies in a sex-specific manner. Lipids and fatty acids were measured in serum and red blood cells (RBC), respectively, in 94 adults (18–30 years) from the GONE FISHIN’ cohort and 118 age-matched individuals from the GOLDN cohort. HDL-c levels were higher and the total cholesterol/HDL-c (TC/HDL-c) ratio was lower in women versus men (p < 0.01). RBC palmitoleic acid and the stearoyl-CoA desaturase index were both higher in women (p < 0.01). Fatty acid desaturase (FADS) pathway activity (estimated using the ratio of eicosapentaenoic acid/alpha-linolenic acid) was higher in men (p < 0.01). The AA genotype for rs1800775 in CETP had a lower TC/HDL-c ratio in men, but not women (p int = 0.03). Independent of sex, major alleles for rs174537 in FADS1 (GG) and rs3211956 in CD36 (TT) had higher arachidonic acid, lower dihomo-γ-linoleic acid, and a higher FADS1 activity compared to minor alleles. The current study showed that blood lipid and fatty acid levels vary between healthy young men and women, but that the observed sex differences are not associated with common variants in candidate lipid metabolism genes. 相似文献
17.
Eaddy Marc Zimmermann Thomas Sherwood Kaitlin D. Garg Vibhav Murphy Gail C. Nagappan Nachiappan Aho Alfred V. 《IEEE transactions on pattern analysis and machine intelligence》2008,34(4):497-515
There is a growing consensus that crosscutting concerns harm code quality. An example of a crosscutting concern is a functional requirement whose implementation is distributed across multiple software modules. We asked the question, "How much does the amount that a concern is crosscutting affect the number of defects in a program?" We conducted three extensive case studies to help answer this question. All three studies revealed a moderate to strong statistically significant correlation between the degree of scattering and the number of defects. This paper describes the experimental framework we developed to conduct the studies, the metrics we adopted and developed to measure the degree of scattering, the studies we performed, the efforts we undertook to remove experimental and other biases, and the results we obtained. In the process, we have formulated a theory that explains why increased scattering might lead to increased defects. 相似文献
18.
Jeremy McAdam Kaitlin McGinnis Rian Ory Kaelin Young Andrew D. Frugé Michael Roberts JoEllen Sefton 《Journal of the International Society of Sports Nutrition》2018,15(1):55
Background
Adequate dietary intake is important for promoting adaptation and prevention of musculoskeletal injury in response to large volumes of physical training such as Army Initial Entry Training (IET). The purpose of this study was to evaluate training volume and dietary intake and estimate energy balance in Army IET soldiers.Methods
Dietary intake was assessed by collecting diet logs for three meals on each of three, non-consecutive days during the first week of IET. Training volume was measured across 13?weeks of training using Actigraph wGT3X accelerometers. Training intensity was classified using Sasaki vector magnitude three cut points. Energy expenditure estimates were calculated during weeks two and three of training using the modified Harris-Benedict equation and by estimation of active energy expenditure using metabolic equivalents for each classification of physical activity. All data is presented as mean?±?standard deviation.Results
A total of 111 male soldiers (ht. =?±?173?±?5.8?cm, age?=?19?±?2?years, mass?=?71.6. ± 12.4?kg) completed diet logs and were monitored with Actigraphs. IET soldiers performed on average 273?±?62?min low, 107?±?42?min moderate, 26?±?22?min vigorous, and 10?±?21?min of very vigorous intensity physical activity daily across 13?weeks. The estimated total daily energy expenditure was on average 3238?±?457 kcals/d during weeks two and three of IET. Compared to week one caloric intake, there was a caloric deficit of 595?±?896 kcals/d on average during weeks two and three of IET. Regression analysis showed that body weight was a significant predictor for negative energy balance (adj. R2?=?0.54, p?<?0.001), whereby a 1?kg increase in body mass was associated with a 53?kcal energy deficit.Conclusions
Based on week one dietary assessment, IET soldiers did not consume adequate calories and nutrients to meet training needs during red phase (weeks one through three). This may directly affect soldier performance and injury frequency. IET soldiers undergo rigorous training, and these data may help direct future guidelines for adequate nourishment to optimize soldier health and performance.19.
This paper examines the conditions under which a dead zone, or a portion of the catalyst devoid of reactant, can form in a porous catalyst in which simultaneous reaction and diffusion are occurring. The condition that allows for the existence of a dead zone is defined by a critical Thiele modulus. When the Thiele modulus – the ratio of chemical reaction to diffusion – is greater than the critical Thiele modulus, a dead zone exists. This dead zone can be mathematically defined by a change of boundary conditions. We examine nth order reactions in isothermal infinite slabs, infinite cylinders, and spheres. In addition, we provide analytical concentration profiles and efficiency factors for zero-order reactions in non-isothermal infinite slabs (in the so-called low beta approximation). We also discuss some common errors and misconceptions associated with this phenomenon. 相似文献
20.
Handley Elizabeth D.; Chassin Laurie; Haller Moira M.; Bountress Kaitlin E.; Dandreaux Danielle; Beltran Iris 《Canadian Metallurgical Quarterly》2011,120(3):528
The present study examined the potential mediating roles of executive and reactive disinhibition in predicting conduct problems, attention-deficit/hyperactivity disorder (ADHD) symptoms, and substance use among adolescents with and without a family history of substance use disorders. Using data from 247 high-risk adolescents, parents, and grandparents, structural equation modeling indicated that reactive disinhibition, as measured by sensation seeking, mediated the effect of familial drug use disorders on all facets of the adolescent externalizing spectrum. Executive disinhibition, as measured by response disinhibition, spatial short term memory, and “trait” impulsivity, was associated with ADHD symptoms. Moreover, although executive functioning weakness were unrelated to familial substance use disorders, adolescents with familial alcohol use disorders were at risk for “trait” impulsivity marked by a lack of planning. These results illustrate the importance of “unpacking” the broad temperament style of disinhibition and of studying the processes that underlie the commonality among facets of the externalizing spectrum and processes that predict specific externalizing outcomes. (PsycINFO Database Record (c) 2011 APA, all rights reserved) 相似文献