414 research outputs found
Evaluation of atmospheric density models and preliminary functional specifications for the Langley Atmospheric Information Retrieval System (LAIRS)
This document presents the results of an extensive survey and comparative evaluation of current atmosphere and wind models for inclusion in the Langley Atmospheric Information Retrieval System (LAIRS). It includes recommended models for use in LAIRS, estimated accuracies for the recommended models, and functional specifications for the development of LAIRS
Side effects of analgesia may significantly reduce quality of life in symptomatic multiple myeloma: a cross-sectional prevalence study
Background Pain is a common symptom in patients with
multiple myeloma (MM). Many patients are dependent on
analgesics and in particular opioids, but there is limited information
on the impact of these drugs and their side effects on
health-related quality of life (HRQoL).
Method In a cross-sectional study, semi-structured interviews
were performed in 21 patients attending the hospital with
symptomatic MM on pain medications. HRQoL was measured
using items 29 and 30 of the European Organisation for
Research and Treatment of Cancer (EORTC) QLQ-C30.
Results Patients were able to recall a median of two (range
0–4) analgesics. They spontaneously identified a median
of two (range 1–5) side effects attributable to their analgesic
medications. Patients’ assessment of HRQoL based on
the EORTC QLQ-C30 questions 29/30 was mean 48.3
(95 % CI; 38.7–57.9) out of 100. Patients’ assessment of
their HRQoL in the hypothetical situation, in which they
would not experience any side effects from analgesics, was
significantly higher: 62.6 (53.5–71.7) (t test, p=0.001).
Conclusion This study provides, for the first time, evidence
that side effects of analgesics are common in symptomatic
MM and may result in a statistically and clinically significant
reduction of self-reported HRQoL
Ligand-Receptor Interactions
The formation and dissociation of specific noncovalent interactions between a
variety of macromolecules play a crucial role in the function of biological
systems. During the last few years, three main lines of research led to a
dramatic improvement of our understanding of these important phenomena. First,
combination of genetic engineering and X ray cristallography made available a
simultaneous knowledg of the precise structure and affinity of series or
related ligand-receptor systems differing by a few well-defined atoms. Second,
improvement of computer power and simulation techniques allowed extended
exploration of the interaction of realistic macromolecules. Third, simultaneous
development of a variety of techniques based on atomic force microscopy,
hydrodynamic flow, biomembrane probes, optical tweezers, magnetic fields or
flexible transducers yielded direct experimental information of the behavior of
single ligand receptor bonds. At the same time, investigation of well defined
cellular models raised the interest of biologists to the kinetic and mechanical
properties of cell membrane receptors. The aim of this review is to give a
description of these advances that benefitted from a largely multidisciplinar
approach
Microsatellite instability and intratumoural heterogeneity in 100 right-sided sporadic colon carcinomas
Microsatellite instability has been proposed as an alternative pathway of colorectal carcinogenesis. The aim of this study was to evaluate the interest of immunohistochemistry as a new tool for highlighting mismatch repair deficiency and to compare the results with a PCR-based microsatellite assay. A total of 100 sporadic proximal colon adenocarcinomas were analysed. The expression of hMLH1, hMSH2 and hMSH6 proteins evaluated by immunohistochemistry was altered in 39% of the cancers, whereas microsatellite instability assessed by PCR was detected in 43%. There was discordance between the two methods in eight cases. After further analyses performed on other tumoural areas for these eight cases, total concordance between the two techniques was observed (Kappa=100%). Our results demonstrate that immunohistochemistry may be as efficient as microsatellite amplification in the detection of unstable phenotype provided that at least two samples of each carcinoma are screened, because of intratumoural heterogeneity
?2-Microglobulin Amyloid Fibril-Induced Membrane Disruption Is Enhanced by Endosomal Lipids and Acidic pH
Although the molecular mechanisms underlying the pathology of amyloidoses are not well understood, the interaction between amyloid proteins and cell membranes is thought to play a role in several amyloid diseases. Amyloid fibrils of ?2-microglobulin (?2m), associated with dialysis-related amyloidosis (DRA), have been shown to cause disruption of anionic lipid bilayers in vitro. However, the effect of lipid composition and the chemical environment in which ?2m-lipid interactions occur have not been investigated previously. Here we examine membrane damage resulting from the interaction of ?2m monomers and fibrils with lipid bilayers. Using dye release, tryptophan fluorescence quenching and fluorescence confocal microscopy assays we investigate the effect of anionic lipid composition and pH on the susceptibility of liposomes to fibril-induced membrane damage. We show that ?2m fibril-induced membrane disruption is modulated by anionic lipid composition and is enhanced by acidic pH. Most strikingly, the greatest degree of membrane disruption is observed for liposomes containing bis(monoacylglycero)phosphate (BMP) at acidic pH, conditions likely to reflect those encountered in the endocytic pathway. The results suggest that the interaction between ?2m fibrils and membranes of endosomal origin may play a role in the molecular mechanism of ?2m amyloid-associated osteoarticular tissue destruction in DRA
Pattern Recognition Software and Techniques for Biological Image Analysis
The increasing prevalence of automated image acquisition systems is enabling new types of microscopy experiments that generate large image datasets. However, there is a perceived lack of robust image analysis systems required to process these diverse datasets. Most automated image analysis systems are tailored for specific types of microscopy, contrast methods, probes, and even cell types. This imposes significant constraints on experimental design, limiting their application to the narrow set of imaging methods for which they were designed. One of the approaches to address these limitations is pattern recognition, which was originally developed for remote sensing, and is increasingly being applied to the biology domain. This approach relies on training a computer to recognize patterns in images rather than developing algorithms or tuning parameters for specific image processing tasks. The generality of this approach promises to enable data mining in extensive image repositories, and provide objective and quantitative imaging assays for routine use. Here, we provide a brief overview of the technologies behind pattern recognition and its use in computer vision for biological and biomedical imaging. We list available software tools that can be used by biologists and suggest practical experimental considerations to make the best use of pattern recognition techniques for imaging assays
Impacts of climate change on plant diseases – opinions and trends
There has been a remarkable scientific output on the topic of how climate change is likely to affect plant diseases in the coming decades. This review addresses the need for review of this burgeoning literature by summarizing opinions of previous reviews and trends in recent studies on the impacts of climate change on plant health. Sudden Oak Death is used as an introductory case study: Californian forests could become even more susceptible to this emerging plant disease, if spring precipitations will be accompanied by warmer temperatures, although climate shifts may also affect the current synchronicity between host cambium activity and pathogen colonization rate. A summary of observed and predicted climate changes, as well as of direct effects of climate change on pathosystems, is provided. Prediction and management of climate change effects on plant health are complicated by indirect effects and the interactions with global change drivers. Uncertainty in models of plant disease development under climate change calls for a diversity of management strategies, from more participatory approaches to interdisciplinary science. Involvement of stakeholders and scientists from outside plant pathology shows the importance of trade-offs, for example in the land-sharing vs. sparing debate. Further research is needed on climate change and plant health in mountain, boreal, Mediterranean and tropical regions, with multiple climate change factors and scenarios (including our responses to it, e.g. the assisted migration of plants), in relation to endophytes, viruses and mycorrhiza, using long-term and large-scale datasets and considering various plant disease control methods
Model parameterization to simulate and compare the PAR absorption potential of two competing plant species
Mountain pastures dominated by the pasture grass Setaria sphacelata in the Andes of southern Ecuador are heavily infested by southern bracken (Pteridium arachnoideum), a major problem for pasture management. Field observations suggest that bracken might outcompete the grass due to its competitive strength with regard to the absorption of photosynthetically active radiation (PAR). To understand the PAR absorption potential of both species, the aims of the current paper are to (1) parameterize a radiation scheme of a two-big-leaf model by deriving structural (LAI, leaf angle parameter) and optical (leaf albedo, transmittance) plant traits for average individuals from field surveys, (2) to initialize the properly parameterized radiation scheme with realistic global irradiation conditions of the Rio San Francisco Valley in the Andes of southern Ecuador, and (3) to compare the PAR absorption capabilities of both species under typical local weather conditions. Field data show that bracken reveals a slightly higher average leaf area index (LAI) and more horizontally oriented leaves in comparison to Setaria. Spectrometer measurements reveal that bracken and Setaria are characterized by a similar average leaf absorptance. Simulations with the average diurnal course of incoming solar radiation (1998–2005) and the mean leaf–sun geometry reveal that PAR absorption is fairly equal for both species. However, the comparison of typical clear and overcast days show that two parameters, (1) the relation of incoming diffuse and direct irradiance, and (2) the leaf–sun geometry play a major role for PAR absorption in the two-big-leaf approach: Under cloudy sky conditions (mainly diffuse irradiance), PAR absorption is slightly higher for Setaria while under clear sky conditions (mainly direct irradiance), the average bracken individual is characterized by a higher PAR absorption potential. (∼74 MJ m−2 year−1). The latter situation which occurs if the maximum daily irradiance exceeds 615 W m−2 is mainly due to the nearly orthogonal incidence of the direct solar beam onto the horizontally oriented frond area which implies a high amount of direct PAR absorption during the noon maximum of direct irradiance. Such situations of solar irradiance favoring a higher PAR absorptance of bracken occur in ∼36% of the observation period (1998–2005). By considering the annual course of PAR irradiance in the San Francisco Valley, the clear advantage of bracken on clear days (36% of all days) is completely compensated by the slight but more frequent advantage of Setaria under overcast conditions (64% of all days). This means that neither bracken nor Setaria show a distinct advantage in PAR absorption capability under the current climatic conditions of the study area
Communications Biophysics
Contains research objectives and summary of research on thirteen research projects split into four section.National Institutes of Health (Grant 1 RO1 NS10737-01)National Institutes of Health (Grant 1 ROI NS10916-01)National Institutes of Health (Grant 5 RO1 NS11000-02)National Institutes of Health (Grant 1 RO1 NS11153-01)Harvard M.I.T. Rehabilitation Engineering CenterU. S. Department of Health, Education, and Welfare, Grant 23-P-55854National Institutes of Health (Grant 1 RO1 NS11680-01)Norlin Music, Inc.Clarence J. LeBel FundNational Institutes of Health (Grant 1 RO1 NS11080-01A1)National Institutes of Health (Grant 5 TO1 GM01555-08)M.I.T. Health Sciences FundBoston City Hospital Purchase Order 1176-05-21335-C
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