Home About us Contact
|
Home About us Contact | ||
|
|
||
Little Improvement (little + improvement)
Selected AbstractsNitric oxide in wound-healingMICROSURGERY, Issue 5 2005Jeff S. Isenberg M.D., M.P.H. Modulation of the complex process of wound-healing remains a surgical challenge. Little improvement beyond controlling infection, gentle tissue handling, and debridement of necrotic tissue has been had in the modern era. However, increasing appreciation of the process from a biomolecular perspective offers the potential for making significant strides in wound modulation. The bioactive molecule nitric oxide was found to have wide-ranging impact on cellular activities, including the cellular responses engendered by wound healing. Current research suggests that nitric oxide and several nitric oxide donors can exert biologic effects, although the particular net responses of cells contributing to wound repair are context-dependent. © 2005 Wiley-Liss, Inc. Microsurgery 25:442,451, 2005. [source] Examining the statistical properties of fine-scale mapping in large-scale association studiesGENETIC EPIDEMIOLOGY, Issue 3 2008Steven Wiltshire Abstract Interpretation of dense single nucleotide polymorphism (SNP) follow-up of genome-wide association or linkage scan signals can be facilitated by establishing expectation for the behaviour of primary mapping signals upon fine-mapping, under both null and alternative hypotheses. We examined the inferences that can be made regarding the posterior probability of a real genetic effect and considered different disease-mapping strategies and prior probabilities of association. We investigated the impact of the extent of linkage disequilibrium between the disease SNP and the primary analysis signal and the extent to which the disease gene can be physically localised under these scenarios. We found that large increases in significance (>2 orders of magnitude) appear in the exclusive domain of genuine genetic effects, especially in the follow-up of genome-wide association scans or consensus regions from multiple linkage scans. Fine-mapping significant association signals that reside directly under linkage peaks yield little improvement in an already high posterior probability of a real effect. Following fine-mapping, those signals that increase in significance also demonstrate improved localisation. We found local linkage disequiliptium patterns around the primary analysis signal(s) and tagging efficacy of typed markers to play an important role in determining a suitable interval for fine-mapping. Our findings help inform the interpretation and design of dense SNP-mapping follow-up studies, thus facilitating discrimination between a genuine genetic effect and chance fluctuation (false positive). Genet. Epidemiol. 2007. © 2007 Wiley-Liss, Inc. [source] The Impact of Industrial Restructuring on Earnings Inequality: The Decline of Steel and Earnings in PittsburghGROWTH AND CHANGE, Issue 1 2004Patricia Beeson ABSTRACT Inter-industry employment shifts were largely responsible for changes in the income distribution in the Pittsburgh region during the 1980s. Kernel density estimators were used, together with decomposition techniques developed by DiNardo et al. (1996) to show that industry shifts were responsible for over 90 percent of the earnings reductions at some points on the earnings distribution. Most of the losses at the lower end of the distribution occurred in the early 1980s as the economy plunged into a deep recession. The recovery in the later part of the decade brought little improvement as earnings in the lower part of the distribution continued to fall with the increase in employment of part-time workers in the low-wage trade and service sectors. [source] The geometrical design of membraneless micro fuel cells: Failure and successINTERNATIONAL JOURNAL OF ENERGY RESEARCH, Issue 10 2010Dewan Hasan Ahmed Abstract A comprehensive numerical study of membraneless micro fuel cells with various geometries is carried out with the aim of reducing the mixing of the anode and cathode fluids and increasing their fuel utilization. Designs with blocks or obstacles in the main channel or a main channel with a wavy shape result in very little improvement in these properties or even in their deterioration. However, some designs with other types of channel cross-section exhibit much less mixing of the two fluids in the main channel. In particular, an octagonal cross-section is found to result in better performance. However, the difficulty of the micro fabrication of fuel cells with this design encourages us to test two other geometries for the cross-section: H-shaped and trident-shaped. The H-shaped cross-section exhibits much less mixing in the main channel and much higher fuel utilization. The fuel cell with a trident-shaped cross-section has two inlets for the anode and cathode fluids and a third inlet for the proton-conducting fluid, and is found to be the best design in that the anode and cathode fluids are more restricted to their respective electrodes (reaction surfaces). Further, in this design the reactants cover only 40% of the channel width, which is much less than in the other designs, and maximum fuel utilization is obtained. The failure and success cases will guide for future geometrical design of any micro fluidic devices where mixing and non-mixing issues are the major concerns. The present numerical results are validated by comparison with literature data. Copyright © 2009 John Wiley & Sons, Ltd. [source] Cognitive, Linguistic and Adaptive Functioning in Williams Syndrome: Trajectories from Early to Middle AdulthoodJOURNAL OF APPLIED RESEARCH IN INTELLECTUAL DISABILITIES, Issue 4 2010Patricia Howlin Background, Little is known about trajectories of cognitive functioning as individuals with Williams syndrome (WS) move though adulthood. Method, The present study investigated cognitive, linguistic and adaptive functioning in adults with WS aged 19,55 years, using both cross-sectional and longitudinal approaches. Results, Data from the cross-sectional study (n = 92; mean age = 32 years) indicated that IQ was comparable across age groups (Full-Scale IQ mean = 56,57) with Verbal IQ being slightly higher than Performance IQ. Daily Living Skills (as measured by the Vineland Adaptive Behavior Scales) were significantly higher in older individuals. Language abilities showed no consistent age-related differences. On formal tests of language, comprehension scores were higher than expressive language scores for almost all individuals, although this pattern was not replicated on the Vineland. In the longitudinal study, a follow-up of 47 individuals (mean age = 37 years) first assessed 12 years previously, similar trajectories were found. IQ remained very stable (FSIQ = 61,62 at both time points); there were significant improvements on the Social and Daily Living domains of the Vineland and significant decreases in Maladaptive scores. There were no improvements in language over time. Conclusions, The data indicate that adults with WS (at least up to the age of 50 years) show no evidence of deterioration in cognitive skills. Adaptive abilities continue to develop although language shows relatively little improvement with time. [source] Psychosocial Adjustment Over a Two,Year Period in Children Referred for Learning Problems: Risk, Resilience, and AdaptationLEARNING DISABILITIES RESEARCH & PRACTICE, Issue 1 2003Lisa G. Sorensen Children with learning difficulties have an increased prevalence of psychosocial adjustment problems. We hypothesized that within the context of a risk and resilience model contextual variables influence adjustment, over and above any effects of academic performance. The Behavior Assessment System for Children (BASC) was used to evaluate the relationship between psychosocial adjustment, changes in academic skills, and contextual factors longitudinally over a two,year period in 100 children (ages 7 to 11) referred for learning problems. Although there was little improvement in academic skills, contextual factors contributed to observed psychosocial outcome. Different factors were salient for parents, teachers, and children. Context,derived vulnerability and protective factors can be important determinants of adjustment in children with learning problems, even though the academic difficulties can remain chronic. [source] How precise are measurements of unit-cell dimensions from single crystals?ACTA CRYSTALLOGRAPHICA SECTION B, Issue 4 2000Frank H. Herbstein The results of single-site and many-site measurements of cell dimensions from single crystals are compared for Bond and four-circle diffractometers using samples of corundum (essentially pure rhombohedral ,-Al2O3, aluminum oxide) of high diffraction quality, where the effects of small changes in temperature and composition (Cr2O3, chromium oxide, in solid solution) can be taken into account. Similar comparisons are made for four-circle diffractometer measurements on ruby (,-Al2O3, with 0.46 wt % Cr in solid solution). The precisions are some parts in 105. There is partial support for the Taylor,Kennard [Acta Cryst. (1986), B42, 112,120] dictum that standard uncertainties (s.u.s) of cell parameters from routine four-circle diffractometer measurements are less than those for many-site measurements by factors of 5 for cell lengths and 2.5 for cell angles. For organic crystals, independent repetitions of adequate quality for comparison and analysis of routine four-circle diffractometer measurements are available only for ,-oxalic acid dihydrate and anthracene. The experimental standard uncertainties given for these two crystals agree reasonably well with the sample s.u.s at room temperature, but appreciably less well at ,100,K, again giving partial support to the Taylor,Kennard dictum. The relation between specimen characteristics and attainable precision is emphasized; the precisions for routine measurements on good quality organic crystals are some parts in 104. Area-detector measurements of cell dimensions have also been appraised; currently published s.u.s from such measurements appear to be highly unreliable, and this is supported by a recent analysis of the operation of such diffractometers [Paciorek et al. (1999). Acta Cryst. A55, 543,557]. Formulation of a standard protocol for such measurements is badly needed. The dangers inherent in high degrees of replication are illustrated by recounting Kapteyn's Parable of the Chinese Emperor. Attention is drawn to the fact that there has been little improvement in claimed precisions over the past 40,60 years. [source] Maternal variation in juvenile survival and growth of triploid hybrids between female rainbow trout and male brown trout and brook charrAQUACULTURE RESEARCH, Issue 2 2005J M Blanc Abstract Related sib-groups of rainbow trout × brown trout and rainbow trout × brook charr triploid hybrids and monospecific diploid and triploid rainbow trout controls were obtained from a common set of rainbow trout dams. On the basis of hybrid juvenile performances, 10 sib-groups were selected and the corresponding diploid rainbow trouts were raised up to adult stage. Females from each group of rainbow trout were used to produce a second generation of hybrid progeny, the performances of which were analysed for grandmaternal variation and relation with first-generation relatives. Results showed that hybrid traits (alevin yield and weight, survival and growth of fingerlings) were strongly influenced by maternal origin, and could be correlated to those of rainbow trout controls, but that maternal abilities had a low rate of inheritance. It was concluded that little improvement can be expected through selective breeding within parental populations. [source] Relationship between change in skin score and disease outcome in diffuse cutaneous systemic sclerosis: Application of a latent linear trajectory modelARTHRITIS & RHEUMATISM, Issue 7 2007Lynne Shand Objective To explore the relationship between changes in the severity of skin disease and morbidity and mortality in patients with diffuse cutaneous systemic sclerosis (dcSSc). Methods From a large single-center cohort, we identified 225 patients with dcSSc for whom serial clinical information was available from within 24 months of the onset of the first non,Raynaud's phenomenon manifestation of SSc. The end points analyzed included death and heart, lung, kidney, and gastrointestinal tract involvement. Latent linear trajectory modeling (LTM) was applied to identify patients with a similar trajectory of modified Rodnan skin thickness score (MRSS) changes over the first 3 years of followup. Clinical outcomes were compared between 3 different LTM subgroups. Results LTM permitted classification of 131 patients (58%) into 1 of 3 subgroups with different skin score trajectories. Survival was lowest in the subgroup of patients who had a high baseline skin score and experienced little improvement during followup (P = 0.003). However, the frequency of clinical end points was similar in the subgroup with the most favorable trajectory (i.e., a low initial MRSS and subsequent improvement) and the subgroup with a high baseline MRSS and no improvement. Interestingly, the end point frequency was greatest in the subgroup with a high initial MRSS and subsequent improvement, suggesting that sustained severe skin disease does not necessarily predict the number of visceral complications, and that the relationship between the skin score and internal organ involvement in dcSSc is more complex than previously thought. Conclusion Although mortality was highest among patients with the worst skin-related outcomes, no simple relationship between burden of disease and change in skin score was observed. [source] Wear of the artificial hip joint material under lubricationASIA-PACIFIC JOURNAL OF CHEMICAL ENGINEERING, Issue 1 2009E. P. J. Waters Abstract A study of wear properties of hip-replacement materials, namely high-nitrogen stainless-steel femoral heads and ultra-high molecular weight polyethylene (UHMWPE), was conducted in a non-conforming apparatus using various liquid lubricants. The liquids used were normal saline solution, sodium azide solution, pure ethanol, aqueous hyaluronic acid and aqueous hyaluronic acid/cholesterol and cholesterol palmitate liquid crystal lubricant. Saline solution proved to be unsuitable as a lubricant while sodium azide that was used as a bactericide provided some evidence of mixed lubrication. A bactericide was included to overcome degradation. The aqueous hyaluronic acid exhibited cushion form lubrication as evidenced by retention of the original polymer surface features within the wear indent. Cholesterol addition showed little improvement on the wear properties but massively increased the bacterial activity. Again, inclusion of a bactericide was necessary. Liquid crystal lubricant significantly reduced wear and the atomic force microscope (AFM) showed that the liquid crystal formed protective layers on the counter face surfaces. The sub-surface of the polymer possessed plastic creep under load but low adhesive wear was present. There also was an absence of sub-micron polymer debris. It was concluded that a dramatic reduction in wear could be achieved by incorporation of liquid crystal lubricant in hip-replacement elements. Copyright © 2009 Curtin University of Technology and John Wiley & Sons, Ltd. [source] Engineering an improved crystal contact across a solvent-mediated interface of human fibroblast growth factor 1ACTA CRYSTALLOGRAPHICA SECTION F (ELECTRONIC), Issue 11 2009Akshaya K. Meher Large-volume protein crystals are a prerequisite for neutron diffraction studies and their production represents a bottleneck in obtaining neutron structures. Many protein crystals that permit the collection of high-resolution X-ray diffraction data are inappropriate for neutron diffraction owing to a plate-type morphology that limits the crystal volume. Human fibroblast growth factor 1 crystallizes in a plate morphology that yields atomic resolution X-ray diffraction data but has insufficient volume for neutron diffraction. The thin physical dimension has been identified as corresponding to the b cell edge and the X-ray structure identified a solvent-mediated crystal contact adjacent to position Glu81 that was hypothesized to limit efficient crystal growth in this dimension. In this report, a series of mutations at this crystal contact designed to both reduce side-chain entropy and replace the solvent-mediated interface with direct side-chain contacts are reported. The results suggest that improved crystal growth is achieved upon the introduction of direct crystal contacts, while little improvement is observed with side-chain entropy-reducing mutations alone. [source] Effect of surfactants on separate hydrolysis fermentation and simultaneous saccharification fermentation of pretreated lodgepole pineBIOTECHNOLOGY PROGRESS, Issue 4 2009Maobing Tu Abstract The effects of surfactants addition on enzymatic hydrolysis and subsequent fermentation of steam exploded lodgepole pine (SELP) and ethanol pretreated lodgepole pine (EPLP) were investigated in this study. Supplementing Tween 80 during cellulase hydrolysis of SELP resulted in a 32% increase in the cellulose-to-glucose yield. However, little improvement was obtained from hydrolyzing EPLP in the presence of the same amount of surfactant. The positive effect of surfactants on SELP hydrolysis led to an increase in final ethanol yield after the fermentation. It was found that the addition of surfactant led to a substantial increase in the amount of free enzymes in the 48 h hydrolysates derived from both substrates. The effect of surfactant addition on final ethanol yield of simultaneous saccharification and fermentation (SSF) was also investigated by using SELP in the presence of additional furfural and hydroxymethylfurfural (HMF). The results showed that the surfactants slightly increased the conversion rates of furfural and HMF during SSF process by Saccharomyces cerevisiae. The presence of furfural and HMF at the experimental concentrations did not affect the final ethanol concentration either. The strategy of applying surfactants in cellulase recycling to reduce enzyme cost is presented. © 2009 American Institute of Chemical Engineers Biotechnol. Prog., 2009 [source] Strategic Selection of Hyperthermophilic Esterases for Resolution of 2-Arylpropionic EstersBIOTECHNOLOGY PROGRESS, Issue 5 2003Amitabh C. Sehgal Homologues to Carboxylesterase NP and Candida rugosa lipase, used for the chiral separation of racemic mixtures of 2-arylpropionic methyl esters, were identified by BLAST searches of available genome sequences for hyperthermophilic microorganisms. Two potential candidates were identified: a putative lysophospholipase from Pyrococcus furiosus (Pfu-LPL) and a carboxylesterase from Sulfolobussolfataricus P1 (Sso-EST1). Although both enzymes showed hydrolytic preference toward the (S) methyl ester, only Sso-EST1 yielded highly optically pure (S) naproxen (%eep , 90) and was thus further investigated. Changes in pH or reaction time showed little improvement in %eep or E values with Sso-EST1. However, the addition of 25% methanol resulted in a 25% increase in E. The effect of various cosolvents on the enantiomeric ratio showed no correlation with the log P or dielectric constant values of the solvent. However, an inverse relationship between E and the denaturation capacity (DC) of the water miscible cosolvents was observed. This was attributed to an increase in enzyme flexibility with increasing solvent DC values leading to a concomitant reduction in the resolving power of Sso-EST1. The results here show that although bioinformatics tools can be used to select candidate biocatalysts for chiral resolution of 2-arylpropionic esters, biochemical characterization is needed to definitively determine functional characteristics. [source] | ||||||||||||||||