71 research outputs found
Bioavailability of Rumen-Protected Carnitine in Lactating Dairy Cows
For this study, 56 lactating Holstein cows (143 ± 72 days in milk) were used in a randomized complete block design to evaluate 2 rumen-protected products compared to crystalline carnitine. Treatments were a) control, b) 3 grams/day crystalline L-carnitine (raw), c) 6 grams/day raw, d) 5 grams/day 40COAT (40% coating, 60% L-carnitine), e) 10 grams/day 40COAT, f) 7.5 grams/day 60COAT (60% coating, 40% L-carnitine), and g) 15 grams/day 60COAT. Treatments were top-dressed to diets twice daily. The 14-day experiment included a 6-day baseline-measurement period with the final 2 days used for data and sample collection and an 8-day treatment period with the final 2 days used for data and sample collection. Plasma, urine, and milk samples were analyzed for L-carnitine. Crystalline (P \u3c 0.001) and 40COAT (P = 0.01) linearly increased plasma L-carnitine, and 60COAT tended to linearly increase plasma L-carnitine (P = 0.08). Total daily excretion (milk + urine) of L-carnitine averaged 1.52 ± 0.04 grams in controls, increased linearly with crystalline and 40COAT, and increased quadratically with 60COAT (all P \u3c 0.05). Crystalline increased plasma L-carnitine and milk + urine L-carnitine more than 40COAT and 60COAT (all P \u3c 0.05). Carnitine supplementation increased carnitine concentrations in plasma, milk, and urine; however, the rumen protection did not provide additional increases in concentration
Tack energy and switchable adhesion of liquid crystal elastomers
The mechanical properties of liquid crystal elastomers (LCEs) make them
suitable candidates for pressure-sensitive adhesives (PSAs). Using the nematic
dumbbell constitutive model, and the block model of PSAs, we study their tack
energy and the debonding process as could be measured experimentally in the
probe-tack test. To investigate their performance as switchable PSAs we compare
the tack energy for the director aligned parallel, and perpendicular to the
substrate normal, and for the isotropic state. We find that the tack energy is
larger in the parallel alignment than the isotropic case by over a factor of
two. The tack energy for the perpendicular alignment can be 50% less than the
isotropic case. We propose a mechanism for reversibly switchable adhesion based
on the reversibility of the isotropic to nematic transition. Finally we
consider the influence of several material parameters that could be used to
tune the stress-strain response
Impact of cavotricuspid isthmus ablation for typical atrial flutter and heart failure in the elderlyâresults of a retrospective multi-center study
IntroductionWhile in the CASTLE-AF trial, in patients with atrial fibrillation and heart failure with reduced ejection fraction, interventional therapy using pulmonary vein isolation was associated with outcome improvement, data on cavotricuspid isthmus ablation (CTIA) in atrial flutter (AFL) in the elderly is rare.MethodsWe included 96 patients between 60 and 85 years with typical AFL and heart failure with reduced or mildly reduced ejection fraction (HFrEF/HFmrEF) treated in two medical centers. 48 patients underwent an electrophysiological study with CTIA, whereas 48 patients received rate or rhythm control and guideline-compliant heart failure therapy. Patients were followed up for 2 years, with emphasis on left ventricular ejection fraction (LVEF) over time. Primary endpoints were cardiovascular mortality and hospitalization for cardiac causes.ResultsPatients with CTIA showed a significant increase in LVEF after 1 (pâ<â0.001) and 2 years (pâ<â0.001) in contrast to baseline LVEF. Improvement of LVEF in the CTIA group was associated with significantly lower 2-year mortality (pâ=â0.003). In the multivariate regression analysis, CTIA remained the relevant factor associated with LVEF improvement (HR: 2.845 CI:95% 1.044â7.755; pâ=â0.041). Elderly patients (â„ 70 years) further benefited from CTIA, since they showed a significantly reduced rehospitalization (pâ=â0.042) and mortality rate after 2 years (pâ=â0.013).ConclusionsCTIA in patients with typical AFL and HFrEF/HFmrEF was associated with significant improvement of LVEF and reduced mortality rates after 2 years. Patient age should not be a primary exclusion criterion for CTIA, since patients â„70 years also seem to benefit from intervention in terms of mortality and hospitalization
Synthesis of carboxylated derivatives of poly(isobutylene-co-isoprene) by azideâalkyne âclickâ chemistry
The final publication is available at Springer via https://dx.doi.org/10.1038/s41428-018-0130-yThe synthesis of carboxylated derivatives of poly(isobutylene-co-isoprene) (isobutyleneâisoprene rubber, IIR) with substitution levels ranging from 1 to 4 mol% and different spacer lengths was accomplished through azideâalkyne Huisgen cycloaddition. Azido-functionalized IIR was first prepared by reacting brominated IIR with sodium azide to full conversion in a 90:10 tetrahydrofuran/N,N-dimethylacetamide mixture. The click reaction of azido-functionalized IIR with acetylenic acids, which was carried out using the copper(I) bromide/N,N,NâČ,Nâł,Nâł-pentamethyldiethylenetriamine catalyst system in tetrahydrofuran, yielded carboxylated IIRs. The products were characterized by 1H NMR and FT-IR spectroscopy, and their molecular weight was determined by size exclusion chromatography analysis. The conversion to carboxylated groups reached up to 100% as determined by NMR spectroscopy but was highly dependent on the type of solvent and the amounts of catalysts and reactants used in the procedures.ARLANXEO Canada Inc.Natural Sciences and Engineering Research Council (NSERC) of Canad
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