796 research outputs found
Project Manager Confidence and Risk Awareness
The purpose of this quantitative study was to examine the relationship between project manager confidence and the ability to assess risk during the early planning stages for a new product development project in a business environment. The problem addressed was that a project managerâs confidence level may lead to insufficient risk awareness and contribute to project failure. The study was conducted among 257 project manager practitioners in the US. The study expanded on the research conducted by Fabricius and BĂŒttgen (2015) which found that project manager overconfidence affects expectations of project success and plays a critical role in the inaccurate assessment of project risk during project planning. A secondary correlation analysis (excluding outliers) found a statistically significant result leading the researcher to reject the null hypothesis, meaning there is evidence to show that overconfident project managers exhibit lower risk awareness. The study has practical implications to project manager practitioners by raising the awareness of understanding how project managers influence risk management in their projects as a prelude to potential project success or failure
Assay of aminoglycosides is influenced by tissue homogenization technique
Recovery of neomycin from tissue homogenates was lower when glass/glass homogenizers were used due to the abrasion of glass which will bind to the drug. Glass homogenizers should be avoided for the determination of aminoglycoside levels in tissues.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/42733/1/18_2005_Article_BF01948411.pd
Haploinsufficiency of myostatin protects against agingârelated declines in muscle function and enhances the longevity of mice
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/112228/1/acel12339-sup-0003-TableS1.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/112228/2/acel12339.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/112228/3/acel12339-sup-0004-TableS2.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/112228/4/acel12339-sup-0002-FigureS1.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/112228/5/acel12339-sup-0001-DataS1.pd
Changes in skeletal muscle and tendon structure and function following genetic inactivation of myostatin in rats
Myostatin is a negative regulator of skeletal muscle and tendon mass. Myostatin deficiency has been well studied in mice, but limited data are available on how myostatin regulates the structure and function of muscles and tendons of larger animals. We hypothesized that, in comparison to wildâtype (MSTN+/+) rats, rats in which zinc finger nucleases were used to genetically inactivate myostatin (MSTNÎ/Î) would exhibit an increase in muscle mass and total force production, a reduction in specific force, an accumulation of type II fibres and a decrease and stiffening of connective tissue. Overall, the muscle and tendon phenotype of myostatinâdeficient rats was markedly different from that of myostatinâdeficient mice, which have impaired contractility and pathological changes to fibres and their extracellular matrix. Extensor digitorum longus and soleus muscles of MSTNÎ/Î rats demonstrated 20â33% increases in mass, 35â45% increases in fibre number, 20â57% increases in isometric force and no differences in specific force. The insulinâlike growth factorâ1 pathway was activated to a greater extent in MSTNÎ/Î muscles, but no substantial differences in atrophyârelated genes were observed. Tendons of MSTNÎ/Î rats had a 20% reduction in peak strain, with no differences in mass, peak stress or stiffness. The general morphology and gene expression patterns were similar between tendons of both genotypes. This large rodent model of myostatin deficiency did not have the negative consequences to muscle fibres and extracellular matrix observed in mouse models, and suggests that the greatest impact of myostatin in the regulation of muscle mass may not be to induce atrophy directly, but rather to block hypertrophy signalling.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/111244/1/tjp6572.pd
Contextualizing genetic risk score for disease screening and rare variant discovery.
Studies of the genetic basis of complex traits have demonstrated a substantial role for common, small-effect variant polygenic burden (PB) as well as large-effect variants (LEV, primarily rare). We identify sufficient conditions in which GWAS-derived PB may be used for well-powered rare pathogenic variant discovery or as a sample prioritization tool for whole-genome or exome sequencing. Through extensive simulations of genetic architectures and generative models of disease liability with parameters informed by empirical data, we quantify the power to detect, among cases, a lower PB in LEV carriers than in non-carriers. Furthermore, we uncover clinically useful conditions wherein the risk derived from the PB is comparable to the LEV-derived risk. The resulting summary-statistics-based methodology (with publicly available software, PB-LEV-SCAN) makes predictions on PB-based LEV screening for 36 complex traits, which we confirm in several disease datasets with available LEV information in the UK Biobank, with important implications on clinical decision-making
Short-term, high-fat diet accelerates disuse atrophy and protein degradation in a muscle-specific manner in mice
Background:
A short-term high-fat diet impairs mitochondrial function and the ability of skeletal muscle to respond to growth stimuli, but it is unknown whether such a diet alters the ability to respond to atrophy signals. The purpose of this study was to determine whether rapid weigh gain induced by a high-fat (HF) diet accelerates denervation-induced muscle atrophy.
Methods:
Adult, male mice (C57BL/6) were fed a control or HF (60ĂÂ % calories as fat) diet for 3ĂÂ weeks (3wHF). Sciatic nerve was sectioned unilaterally for the final 5 or 14ĂÂ days of the diet. Soleus and extensor digitorum longus (EDL) muscles were removed and incubated in vitro to determine rates of protein degradation and subsequently homogenized for determination of protein levels of LC3, ubiquitination, myosin heavy chain (MHC) distribution, and mitochondrial subunits.
Results:
When mice were fed the 3wHF diet, whole-body fat mass more than doubled, but basal (innervated) muscle weights, rates of protein degradation, LC3 content, mitochondrial protein content, and myosin isoform distribution were not significantly different than with the control diet in either soleus or EDL. However in the 14ĂÂ day denervated soleus, the 3wHF diet significantly augmented loss of mass, proteolysis rate, amount of the autophagosome marker LC3 II, and the amount of overall ubiquitination as compared to the control fed mice. On the contrary, the 3wHF diet had no significant effect in the EDL on amount of mass loss, proteolysis rate, LC3 levels, or ubiquitination. Fourteen days denervation also induced a loss of mitochondrial proteins in the soleus but not the EDL, regardless of the diet.
Conclusions:
Taken together, a short-term, high-fat diet augments denervation muscle atrophy by induction of protein degradation in the mitochondria-rich soleus but not in the glycolytic EDL. These findings suggest that the denervation-induced loss of mitochondria and HF diet-induced impairment of mitochondrial function may combine to promote skeletal muscle atrophy
Carbon dioxide and ocean acidification observations in UK waters. Synthesis report with a focus on 2010â2015
Key messages: 1.1 The process of ocean acidification is now relatively well-documented at the global scale as a long-term trend in the open ocean. However, short-term and spatial variability can be high. 1.2 New datasets made available since Charting Progress 2 make it possible to greatly improve the characterisation of CO2 and ocean acidification in UK waters. 3.1 Recent UK cruise data contribute to large gaps in national and global datasets. 3.2 The new UK measurements confirm that pH is highly variable, therefore it is important to measure consistently to determine any long term trends. 3.3 Over the past 30 years, North Sea pH has decreased at 0.0035±0.0014 pH units per year. 3.4 Upper ocean pH values are highest in spring, lowest in autumn. These changes reflect the seasonal cycles in photosynthesis, respiration (decomposition) and water mixing. 3.5 Carbonate saturation states are minimal in the winter, and lower in 7 more northerly, colder waters. This temperature-dependence could have implications for future warming of the seas. 3.6 Over the annual cycle, North-west European seas are net sinks of CO2. However, during late summer to autumn months, some coastal waters may be significant sources. 3.7 In seasonally-stratified waters, sea-floor organisms naturally experience lower pH and saturation states; they may therefore be more vulnerable to threshold changes. 3.8 Large pH changes (0.5 - 1.0 units) can occur in the top 1 cm of sediment; however, such effects are not well-documented. 3.9 A coupled forecast model estimates the decrease in pH trend within the North Sea to be -0.0036±0.00034 pH units per year, under a high greenhouse gas emissions scenario (RCP 8.5). 3.10 Seasonal estimates from the forecast model demonstrate areas of the North Sea that are particularly vulnerable to aragonite undersaturation
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Older onset essential tremor : more rapid progression and more degenerative pathology
There are few data on rate of progression in essential tremor (ET). To quantify the rate of tremor progression in a cross-sectional sample of 348 ET cases in an epidemiological study; characterize the relationship between age of tremor onset and rate of tremor progression in that sample; and characterize the relationship between age of tremor onset, rate of tremor progression, and severity of underlying brain changes in 9 cases from a brain repository. Rate of tremor progression was defined as tremor severity divided by duration. The degeneration index = number of torpedoes per section divided by Purkinje cell linear density. In the epidemiological study, older age of tremor onset was associated with faster rate of tremor progression (P < 0.001). In the brain repository, older age of tremor onset was associated with higher degeneration index (P = 0.037), and higher degeneration index was associated with faster rate of tremor progression (P = 0.018). In a large clinical sample, older age of onset was associated with more rapid tremor progression. In a brain bank, older age of onset was associated with more degenerative pathology in the cerebellum. As in several neurodegenerative disorders, in older onset cases, it is possible that the disease advances more rapidly
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