617 research outputs found
What goes in, must come out:combining scat-based molecular diet analysis and quantification of ingested microplastics in a marine top predator
Context: Microplastics (plastic particles <5 mm in size) are highly available for ingestion by a wide range of organisms, either through direct consumption or indirectly, via trophic transfer, from prey to predator. The latter is a poorly understood, but potentially major, route of microplastic ingestion for marine top predators.Approach: We developed a novel and effective methodology pipeline to investigate dietary exposure of wild top predators (grey seals; Halichoerus grypus) to microplastics, by combining scat-based molecular techniques with a microplastic isolation method. We employed DNA metabarcoding, a rapid method of biodiversity assessment, to garner detailed information on prey composition from scats, and investigated the potential relationship between diet and microplastic burden.Results: Outcomes of the method development process and results of both diet composition from metabarcoding analysis and detection of microplastics are presented. Importantly, the pipeline performed well and initial results suggest the frequency of microplastics detected in seal scats may be related to the type of prey consumed. Conclusions: Our non-invasive, data rich approach maximises time and resource-efficiency, while minimising costs and sample volumes required for analysis. This pipeline could be used to underpin a much-needed increase in understanding of the relationship between diet composition and rates of microplastic ingestion in high trophic-level species.<br/
Adaptive Control Based on Retrospective Cost Optimization
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/83558/1/AIAA-46741-507.pd
Contribution of macrophages to proteolysis and plasmin activity in ewe bulk milk.
A total of 225 bulk sheep milk samples were collected from 5 intensively managed flocks during early, mid, and late lactation to assess the contribution of macrophages to the regulation of the plasmin-plasminogen system. Samples were analyzed for composition, somatic cell counts, milk renneting characteristics, and for plasmin (PL), plasminogen (PG), and plasminogen activators (PA) activities. Isolation of macrophages from milk was performed using a magnetic positive separation and mouse antiovine macrophage antibody; separated cells were lysed by several freeze-thaw cycles, and activity of urokinase PA (u-PA) was determined. Plasmin activity decreased during lactation (42.06 +/- 0.66, early; 31.29 +/- 0.66, mid; 28.19 +/- 0.66 U/mL, late). The reduction in PL activity recorded in the mid and late lactation milk matched the increase in PG:PL ratio. The activity of PA increased throughout lactation; the highest value being recorded in the late lactation milk (260.20 +/- 8.66 U/mL). Counts of isolated and concentrated macrophages were higher in early and mid lactation milk (3.89 +/- 0.08 and 3.98 +/- 0.08 log10 cells/mL, respectively) than in late lactation milk (3.42 +/- 0.08 log10 cells/mL). Stage of lactation did not influence the activity of u-PA detected in isolated macrophages. The activity of u-PA associated with isolated milk macrophages only minimally contributed to total PA activity detected in milk. Proteolytic enzymes, associated with isolated macrophages, act on alpha-casein hydrolysis, as shown by urea-PAGE electrophoresis analysis. Somatic cell counts did not exceed 600,000 cells/mL, and this threshold can be considered a good index of health status of the flock and of the ability of milk to being processed. Our results lend support to the hypothesis that macrophages in ewe bulk milk from healthy flocks only slightly contribute to the activation of the PL-PG system
Comments on âoutput feedback adaptive command following and disturbance rejection for nonminimum phase uncertain dynamical systemsâ
We provide numerical examples and analysis to show that the adaptive controller given by Theorem 3.1 of Yucelen et al. 1 may fail to stabilize plants under the stated conditions. Copyright © 2011 John Wiley & Sons, Ltd.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/83465/1/1235_ftp.pd
Effect of solar radiation and flaxseed supplementation on milk production and fatty acid profile of lactating ewes under high ambient temperature
Abstract The objectives of this study were to evaluate the effects of protection from solar radiation and whole flaxseed supplementation on milk yield and milk fatty acid profile in lactating ewes exposed to high ambient temperature. The experiment was conducted during summer and involved 40 ewes divided into 4 groups. The ewes were either exposed (not offered shade) or protected from solar radiation (offered shade). For each solar radiation treatment, ewes were supplemented with whole flaxseed or not. Milk samples from each ewe were collected at the morning and afternoon milking every week, and analyzed for pH, total protein, casein, fat, and lactose content, somatic cell count, and renneting parameters (clotting time, rate of clot formation, and clot firmness after 30min). At the beginning of the experiment, and then at d 23 and 44, milk samples were analyzed for milk fatty acids using gas chromatography. Flaxseed supplementation significantly increased milk yield, fat, protein, and casein yields, and somatic cell count, and increased fat and lactose contents of milk. A decrease of saturated fatty acids from C6:0 to C16:0 and an increase of C18:1 trans -11 and C18:2 cis- 9, trans -11 was observed in milk from flaxseed-supplemented ewes. Flaxseed supplementation decreased saturated fatty acids content and increased total monounsaturated fatty acids content, the total content of isomers of conjugated linoleic acid, and polyunsaturated fatty acids content in milk. Flaxseed also increased the α-linolenic acid content of milk. As a result, milk from supplemented groups showed an increase in n-3 fatty acid content. Flaxseed supplementation decreased short-chain and medium-chain fatty acids, and increased long-chain fatty acid content of milk. On average, flaxseed supplementation increased the C18:2 cis -9, trans -11/C18:1 trans -11 Π9 -desaturase index starting from d 23 of the experiment, in correspondence with the highest C18:2 cis -9, trans -11 content of milk from flaxseed-supplemented ewes. Flaxseed decreased atherogenic and thrombogenic indices of milk. Protection from solar radiation during summer did not improve yield and composition of ewe milk. Nevertheless, milk from ewes exposed to solar radiation showed decreased long-chain fatty acid and polyunsaturated fatty acids contents, and in particular, decreased vaccenic acid, rumenic acid, and total conjugated linoleic acid contents
Particle characteristics of microplastics contaminating the mussel Mytilus edulis and their surrounding environments
This is the final version. Available on open access from Elsevier via the DOI in this recordWe investigated the environmental partitioning and particle characteristics of macro-, meso- and microplastics and their uptake into the mussel, Mytilus edulis. Sediment samples, overlying seawater and mussels from 9 intertidal locations in the South West of England were analysed for abundance and type of microplastic. Micro- and mesoplastic-like particles were found in 88.5% of the 269 mussels sampled, ranging from 1.43 to 7.64 items per mussel. Of these plastic particles, 70.9% were identified as semi-synthetic (mainly modified-cellulose). Mussel microplastic abundance, but not polymer type, was correlated with that of their surrounding sediment, but not with sea-surface microplastic concentration or mussel size for our study sites. We found significant differences in the relative abundance of polymer types and particle sizes between seawater, sediment, and mussels, with mussels over-representing modified-cellulose fibre abundance but under-representing polyvinyl. Mussels contained significantly smaller plastic fragments than their surrounding sediment and shorter fibres than their overlying seawater
Unsteady low-Reynolds number flow control in different regimes
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/106476/1/AIAA2013-353.pd
Prevalence of obesity and obesity-associated muscle wasting in patients on peritoneal dialysis
Background and aims: A progressive decrease in muscle mass until full-blown sarcopenia may occur in patients on peritoneal dialysis (PD) and worsen their life quality and expectancy. Here we investigate the prevalence of obesity and obesity-associated muscle wasting in PD patients. Patients and methods: The study design was observational, cross sectional. Body composition was assessed with BIA and BIVA in 88 PD patients (53.4 ± 13.1 years; 67% male). Patients with obesity and/or with reduced muscle mass were identified using FMI and SM/BW cutoff values, respectively. Inflammatory status was assessed by measuring CRP and fibrinogen blood levels. Results: A total of 44.3% of the patients showed a reduced muscle mass (37.5% moderate and 6.8% severe). The prevalence of obesity was 6.1%, 81.8%, and 100% in patients with normal, moderately, and severely reduced muscle mass, respectively (p < 0.05). Of the total, 15.2% of the patients with normal muscle mass, 18.4% of those with moderately reduced muscle mass, and 66.7% of those with severely reduced muscle mass had diabetes. The prevalence of severe muscle mass loss was higher in those with diabetes than in those without diabetes (22.2% vs. 2.8%, p < 0.05). Patients with obesity-associated muscle wasting showed higher fibrinogen (613.9 ± 155.1 vs. 512.9 ± 159.5 mg/dL, p < 0.05) and CPR (1.4 ± 1.3 vs. 0.6 ± 0.8 mg/dL, p < 0.05) blood concentrations than those with normal body composition. Conclusion: Obesity and diabetes were strongly associated with muscle mass loss in our PD patients. It remains to be established whether prevention of obesity with nutritional interventions can halt the occurrence of muscle mass loss in patients on PD
Retrospective Cost Adaptive Flow Control Using a Dielectric Barrier Discharge Actuator
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/76651/1/AIAA-2009-5857-706.pd
Proliferative and apoptotic pathways in the testis of quail coturnix coturnix during the seasonal reproductive cycle
The quail Coturnix coturnix is a seasonal breeding species, with the annual reproductive cycle of its testes comprising an activation phase and a regression phase. Our previous results have proven that the testicular levels of both 17ÎČâestradiol (E2) and androgens are higher during the reproductive period compared to the nonâreproductive period, which led us to hypothesize that estrogens and androgens may act synergistically to initiate spermatogenesis. The present study was, therefore, aimed to investigate the estrogen responsive system in quail testis in relation to the reproduction seasonality, with a focus on the molecular pathways elicited in both active and regressive quail testes. Western blotting and immunohistochemistry analysis revealed that the expression of ERα, which is the predominant form of estrogen receptors in quail testis, was correlated with E2 concentration, suggesting that increased levels of E2âinduced ERα could play a key role in the resumption of spermatogenesis during the reproductive period, when both PCNA and SYCP3, the mitotic and meiotic markers, respectively, were also increased. In the reproductive period we also found the activation of the ERK1/2 and Aktâ1 kinase pathways and an increase in second messengers cAMP and cGMP levels. In the nonâreproductive phase, when the E2/ERα levels were low, the inactivation of ERK1/2 and Aktâ1 pathways favored apoptotic events due to an increase in the levels of Bax and cytochrome C, with a consequent regression of the gonad
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