2,102 research outputs found
Effects of ursodeoxycholic acid on synthesis of cholesterol and bile acids in healthy subjects
Background/Aims: Ursodeoxycholic acid ( UDCA) decreases biliary secretion of cholesterol and is therefore used for the dissolution of cholesterol gallstones. It remains unclear whether these changes in biliary cholesterol excretion are associated with changes in cholesterol synthesis and bile acid synthesis. We therefore studied the activities of rate-limiting enzymes of cholesterol synthesis and bile acid synthesis, 3-hydroxy-3-methyl-glutarylcoenzyme A reductase and cholesterol 7alpha-hydroxylase, respectively, in normal subjects during UDCA feeding. Methods: UDCA was given to 8 healthy volunteers ( 5 men, 3 women; age 24-44 years) in a single dose of 10-15 mg/kg body weight for 40 days. Before and during ( days 3, 5, 10, 20, 30 and 40) UDCA treatment, urinary excretion of mevalonic acid and serum concentrations of 7alpha-hydroxy-4-cholesten-3-one (7alpha-HCO) were determined as markers of cholesterol and bile acid synthesis, respectively. The Wilcoxon signed rank test and Spearman's rank correlation coefficient were used for statistical analysis. Results: Cholesterol synthesis and serum lipid concentrations remained unchanged during UDCA treatment for 40 days. However, synthesis of bile acids increased during long-term treatment with UDCA as reflected by an increase in 7alpha-HCO serum concentrations from 39.7 +/- 21.3 ng/ml (median 32.8 ng/ml) before treatment to 64.0 +/- 30.4 ng/ml (median 77.5 ng/ml) at days 30-40 of UDCA treatment ( p < 0.05). Conclusions: UDCA treatment does not affect cholesterol synthesis in the liver, but does increase bile acid synthesis after prolonged treatment. This may represent a compensatory change following decreased absorption of endogenous bile acids as observed with UDCA therapy
Note on the Hydrolysis of Nitrobenzene
Wohl describes the oxidation of nitrobenzene to nitrophenols by the action of powdered potassium hydroxide at temperatures between 60° and 90° C. This reaction does not take place under similar conditions with solid sodium hydroxide
Potential of Forages in Crop Diversification and Crop Rotation
Redesign of agricultural systems according to ecological principles has been proposed for the development of sustainable systems. We review a wide variety of ecologically-based crop production practices that focus on forage crops in farming systems and discuss their potential role in enhancing the profitability, environmental sustainability and resilience. Crop-livestock systems that most closely mimic natural systems through appropriate integration of diverse components appear to offer the greatest potential benefits. These systems are more energy efficient and combine high productivity with low ecological footprint. Greater understanding of ecological relationships within crop-livestock systems are required to purposefully and proactively redesign agricultural systems for profitability, sustainability and resilience
Is statistical learning trainable?
Statistical learning (SL) is the ability to implicitly extract regularities in the environment, and likely supports various
higher-order behaviors, from language to music and vision. While specific patterns experience are likely to influence SL outcomes, this ability is tacitly conceptualized as a fixed construct, and few studies to date have investigated how
experience may shape statistical learning. We report one experiment that directly tested whether SL can be modulated by previous experience. We used a prepost treatment design allowing us to pinpoint what specific
aspects of \u201cprevious experience\u201d matter for SL. The results show that performance on an artificial grammar learning task at post-test depends on whether the grammar to be learned at post-test matches the underlying grammar structures learned during treatment. Our study is the first to adopt a pre-post test design to directly modulate the effects of learning on learning itself
Electron kinetics at the plasma interface
The most fundamental response of an ionized gas to a macroscopic object is
the formation of the plasma sheath. It is an electron depleted space charge
region, adjacent to the object, which screens the object's negative charge
arising from the accumulation of electrons from the plasma. The plasma sheath
is thus the positively charged part of an electric double layer whose
negatively charged part is inside the wall. In the course of the Transregional
Collaborative Research Center SFB/TRR24 we investigated, from a microscopic
point of view, the elementary charge transfer processes responsible for the
electric double layer at a floating plasma-wall interface and made first steps
towards a description of the negative part of the layer inside the wall. Below
we review our work in a colloquial manner, describe possible extensions, and
identify key issues which need to be resolved to make further progress in the
understanding of the electron kinetics across plasma-wall interfaces.Comment: 14 pages, 8 figure
Physical Fitness Training in Patients with Subacute Stroke (PHYS-STROKE): multicentre, randomised controlled, endpoint blinded trial
OBJECTIVE:
To determine the safety and efficacy of aerobic exercise on activities of daily living in the subacute phase after stroke.
DESIGN:
Multicentre, randomised controlled, endpoint blinded trial.
SETTING:
Seven inpatient rehabilitation sites in Germany (2013-17).
PARTICIPANTS:
200 adults with subacute stroke (days 5-45 after stroke) with a median National Institutes of Health stroke scale (NIHSS, range 0-42 points, higher values indicating more severe strokes) score of 8 (interquartile range 5-12) were randomly assigned (1:1) to aerobic physical fitness training (n=105) or relaxation sessions (n=95, control group) in addition to standard care.
INTERVENTION:
Participants received either aerobic, bodyweight supported, treadmill based physical fitness training or relaxation sessions, each for 25 minutes, five times weekly for four weeks, in addition to standard rehabilitation therapy. Investigators and endpoint assessors were masked to treatment assignment.
MAIN OUTCOME MEASURES:
The primary outcomes were change in maximal walking speed (m/s) in the 10 m walking test and change in Barthel index scores (range 0-100 points, higher scores indicating less disability) three months after stroke compared with baseline. Safety outcomes were recurrent cardiovascular events, including stroke, hospital readmissions, and death within three months after stroke. Efficacy was tested with analysis of covariance for each primary outcome in the full analysis set. Multiple imputation was used to account for missing values.
RESULTS:
Compared with relaxation, aerobic physical fitness training did not result in a significantly higher mean change in maximal walking speed (adjusted treatment effect 0.1 m/s (95% confidence interval 0.0 to 0.2 m/s), P=0.23) or mean change in Barthel index score (0 (-5 to 5), P=0.99) at three months after stroke. A higher rate of serious adverse events was observed in the aerobic group compared with relaxation group (incidence rate ratio 1.81, 95% confidence interval 0.97 to 3.36).
CONCLUSIONS:
Among moderately to severely affected adults with subacute stroke, aerobic bodyweight supported, treadmill based physical fitness training was not superior to relaxation sessions for maximal walking speed and Barthel index score but did suggest higher rates of adverse events. These results do not appear to support the use of aerobic bodyweight supported fitness training in people with subacute stroke to improve activities of daily living or maximal walking speed and should be considered in future guidelines.
TRIAL REGISTRATION:
ClinicalTrials.gov NCT01953549
Refining multiple sequence alignments with conserved core regions
Accurate multiple sequence alignments of proteins are very important to several areas of computational biology and provide an understanding of phylogenetic history of domain families, their identification and classification. This article presents a new algorithm, REFINER, that refines a multiple sequence alignment by iterative realignment of its individual sequences with the predetermined conserved core (block) model of a protein family. Realignment of each sequence can correct misalignments between a given sequence and the rest of the profile and at the same time preserves the family's overall block model. Large-scale benchmarking studies showed a noticeable improvement of alignment after refinement. This can be inferred from the increased alignment score and enhanced sensitivity for database searching using the sequence profiles derived from refined alignments compared with the original alignments. A standalone version of the program is available by ftp distribution () and will be incorporated into the next release of the Cn3D structure/alignment viewer
Universality and its Origins at the Amorphous Solidification Transition
Systems undergoing an equilibrium phase transition from a liquid state to an
amorphous solid state exhibit certain universal characteristics. Chief among
these are the fraction of particles that are randomly localized and the scaling
functions that describe the order parameter and (equivalently) the statistical
distribution of localization lengths for these localized particles. The purpose
of this Paper is to discuss the origins and consequences of this universality,
and in doing so, three themes are explored. First, a replica-Landau-type
approach is formulated for the universality class of systems that are composed
of extended objects connected by permanent random constraints and undergo
amorphous solidification at a critical density of constraints. This formulation
generalizes the cases of randomly cross-linked and end-linked macromolecular
systems, discussed previously. The universal replica free energy is
constructed, in terms of the replica order parameter appropriate to amorphous
solidification, the value of the order parameter is obtained in the liquid and
amorphous solid states, and the chief universal characteristics are determined.
Second, the theory is reformulated in terms of the distribution of local static
density fluctuations rather than the replica order parameter. It is shown that
a suitable free energy can be constructed, depending on the distribution of
static density fluctuations, and that this formulation yields precisely the
same conclusions as the replica approach. Third, the universal predictions of
the theory are compared with the results of extensive numerical simulations of
randomly cross-linked macromolecular systems, due to Barsky and Plischke, and
excellent agreement is found.Comment: 10 pages, including 3 figures (REVTEX
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