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PubMed2000

Influence of dry environment on epidermal function.

Recent studies have demonstrated that a dry environment contributes to the exacerbation of cutaneous disorders such as epidermal hyperplasia, mast cell degranulation, and cytokine secretion. The effects of a dry environment on the skin can be prevented by occlusion with water-impermeable material or topical application of a humectant. The stratum corneum, which protects internal organs from the environment, has two functions: a water-impermeable barrier function and a buffer function against a dry environment. Regulation of protease activity or ionic balance in the epidermis can accelerate barrier repair after injury. Improvement of the stratum corneum homeostasis can ameliorate skin damage induced by barrier disruption in a dry environment.

Animals↗

PubMed1997

High-resolution polypeptide structure in a lamellar phase lipid environment from solid state NMR derived orientational constraints.

BACKGROUND: Solid-state nuclear magnetic resonance (NMR) spectroscopy provides novel structural constraints from uniformly aligned samples. These orientational constraints orient specific atomic sites with respect to the magnetic field direction and the unique molecular axis of alignment. Solid-state NMR is uniquely and ideally suited for providing such structural constraints on polypeptides and proteins in a lamellar phase lipid environment. Membrane protein structure represents a great challenge for structural biologists; a new approach for characterizing high resolution three-dimensional structure in such an environment is needed. RESULTS: The optimal use of orientational constraints for defining three-dimensional structures is demonstrated with the elucidation of the gramicidin A channel structure at high resolution. Initial structures are refined against both the experimental constraints and the CHARMM energy using a novel simulated-annealing protocol to define torsion angle solutions with an error bar of approximately +/- 5 degrees. CONCLUSIONS: This analysis results in the determination of a high-resolution, time averaged structure of gramicidin A obtained in a lipid bilayer environment above the gel-to-liquid crystalline phase transition temperature. It is demonstrated that solid-state NMR can be used to establish polypeptide, and potentially protein, structures in such an environment. Furthermore, this high-resolution structure is demonstrated to provide new insights into polypeptide function. For the gramicidin A channel the roles of the indole groups that facilitate ion transport and details of the cation solvation environment provided by the amide oxygens are characterized.

Amino Acid Sequence↗

PubMed2003

The LONI Pipeline Processing Environment.

The analysis of raw data in neuroimaging has become a computationally entrenched process with many intricate steps run on increasingly larger datasets. Many software packages exist that provide either complete analyses or specific steps in an analysis. These packages often possess diverse input and output requirements, utilize different file formats, run in particular environments, and have limited abilities with certain types of data. The combination of these packages to achieve more sensitive and accurate results has become a common tactic in brain mapping studies but requires much work to ensure valid interoperation between programs. The handling, organization, and storage of intermediate data can prove difficult as well. The LONI Pipeline Processing Environment is a simple, efficient, and distributed computing solution to these problems enabling software inclusion from different laboratories in different environments. It is used here to derive a T1-weighted MRI atlas of the human brain from 452 normal young adult subjects with fully automated processing. The LONI Pipeline Processing Environment's parallel processing efficiency using an integrated client/server dataflow model was 80.9% when running the atlas generation pipeline from a PC client (Acer TravelMate 340T) on 48 dedicated server processors (Silicon Graphics Inc. Origin 3000). The environment was 97.5% efficient when the same analysis was run on eight dedicated processors.

Brain Mapping↗

PubMed1999

The built environment as a component of quality care: understanding and including the patient's perspective.

BACKGROUND: Although there has been little systematic assessment of how the built environment of health care facilities affects the quality of care, the built environment is a major element of structure of care--one of three facets of quality. Yet in contrast to the growing trend of using consumer perceptions of both processes and outcomes of care in QI activities, quality assessments of the structure of care do not currently rely on patient feedback. PURPOSE OF PROJECT: During the initial phase of a multiphase project, nine focus groups were conducted in 1997 to identify the salient dimensions of experience from the patient's perspective. The content of these focus groups guided the development of assessment tools in the second phase of the project, which began in February 1998. FINDINGS: Participants in three focus groups that were held in each of three settings--ambulatory care, acute care, and long term care--described in detail a variety of reactions to the built environment. Analysis revealed eight consistent themes in what patients and family member consumers look for in the built environment of health care. In all three settings, they want an environment, for example, that facilitates a connection to staff and caregivers, is conducive to a sense of well-being, and facilitates a connection to the outside world. DISCUSSION: Data derived from the focus group research has guided the development of quantitative survey and assessment tools. For each setting, patient-centered checklists and questionnaires are designed to help institutions set priorities for the improvement of facility design from the patient's perspective.

Facility Design and Construction↗

PubMed2001

How muscles accommodate movement in different physical environments: aquatic vs. terrestrial locomotion in vertebrates.

Representatives of nearly all vertebrate classes are capable of coordinated movement through aquatic and terrestrial environments. Though there are good data from a variety of species on basic patterns of muscle recruitment during locomotion in a single environment, we know much less about how vertebrates use the same musculoskeletal structures to accommodate locomotion in physically distinct environments. To address this issue, we have gathered data from a broad range of vertebrates that move successfully through water and across land, including eels, toads, turtles and rats. Using high-speed video in combination with electromyography and sonomicrometry, we have quantified and compared the activity and strain of individual muscles and the movements they generate during aquatic vs. terrestrial locomotion. In each focal species, transitions in environment consistently elicit alterations in motor output by major locomotor muscles, including changes in the intensity and duration of muscle activity and shifts in the timing of activity with respect to muscle length change. In many cases, these alterations likely change the functional roles played by muscles between aquatic and terrestrial locomotion. Thus, a variety of forms of motor plasticity appear to underlie the ability of many species to move successfully through different physical environments and produce diverse behaviors in nature.

Animals↗

PubMed1992

Phenotypic plasticity for life-history traits in Drosophila melanogaster. III. Effect of the environment on genetic parameters.

We estimated genetic and environmental variance components for developmental time and dry weight at eclosion in Drosophila melanogaster raised in ten different environments (all combinations of 22, 25 and 28 degrees C and 0.5, 1 and 4% yeast concentration, and 0.25% yeast at 25 degrees C). We used six homozygous lines derived from a natural population for complete diallel crosses in each environment. Additive genetic variances were consistently low for both traits (h2 around 10%). The additive genetic variance of developmental time was larger at lower yeast concentrations, but the heritability did not increase because other components were also larger. The additive genetic effects of the six parental lines changed ranks across environments, suggesting a mechanism for the maintenance of genetic variation in heterogenous environments. The variance due to non-directional dominance was small in most environments. However, there was directional dominance in the form of inbreeding depression for both traits. It was pronounced at high yeast levels and temperatures but disappeared when yeast or temperature were decreased. This meant that the heterozygous flies were more sensitive to environmental differences than homozygous flies. Because dominance effects are not heritable, this suggests that the evolution of plasticity can be constrained when dominance effects are important as a mechanism for plasticity.

Adaptation, Physiological↗

PubMed1998

QTL mapping of genotype-environment interaction for fitness in Drosophila melanogaster.

A fundamental assumption of models for the maintenance of genetic variation by environmental heterogeneity is that selection favours alternative alleles in different environments. It is not clear, however, whether such antagonistic pleiotropy is common. We mapped quantitative trait loci (QTLs) causing variation for reproductive performance in each of three environmental treatments among a set of 98 recombinant inbred (RI) lines derived from a cross between two D. melanogaster laboratory strains. The three treatments were standard medium at 25 degrees C, ethanol-supplemented medium at 25 degrees C, and standard medium at 18 degrees C. The RI lines showed highly significant genotype-environment interaction for the fitness measure. Of six QTLs with significant effects on fitness in at least one of the environments, five had significantly different effects at the different temperatures. In each case, the QTL by temperature interaction arose because the QTL had stronger effects at one temperature than at the other. No evidence for QTLs with opposite fitness effects in different environments was found. These results, together with those of recent studies of crop plants, suggest that antagonistic pleiotropy is a relatively uncommon form of genotype-environment interaction for fitness, but additional studies of natural populations are needed to confirm this conclusion.

Animals↗

PubMed1993

A molecular characterization of Clostridium difficile isolates from humans, animals and their environments.

It is generally accepted that most patients with Clostridium difficile-associated diarrhoea acquire the organism from the environment. Recently we demonstrated that household pets may constitute a significant reservoir of C. difficile through gastrointestinal carriage in up to 39% of cats and dogs. These findings suggested that direct transmission from household pets, or contamination of the environment by them, may be a factor in the pathogenesis of C. difficile-associated diarrhoea. To investigate this possibility, we examined isolates of C. difficile from humans, pets and the environment by restriction enzyme analysis (REA) and restriction fragment length polymorphism (RFLP) typing using enhanced chemiluminescence. Both REA and RFLP typing methods used Hind III digests of chromosomal DNA. A total of 116 isolates of C. difficile from pets (26), veterinary clinic environmental sites (33), humans (37) and hospital environmental sites (20) was examined. REA was far more discriminatory than RFLP typing and for all isolates there were 34 REA types versus 6 RFLP types. There was good correlation between the REA types found in isolates from pets and from the veterinary clinic environment, and between isolates from humans and from those found in the hospital environment. There was, however, no correlation between REA type of C. difficile found in pets and isolates of human origin. We conclude that there may still be a risk of humans acquiring C. difficile from domestic pets as these findings may be the result of geographical variation.

Animals↗

PubMed2004

A microfluidics approach to the problem of creating separate solution environments accessible from macroscopic volumes.

We report on a microfluidic device that generates separate solution environments in macroscopic volumes. Spatially distinct patterns are created by emitting fluids from 16 different sources (closely spaced microchannels) into a solution-filled macroscopic chamber. The fluid in neighboring microchannels couples viscously in the macroscopic container, generating one single interdigitated stream. Scanning nanoelectrode amperometry was used for characterizing the concentration landscape and the diffusion zones between solutions running in parallel at different coordinates in the stream. These experiments were complemented by finite element simulations of the Navier-Stokes and mass transport equations to describe the velocity distributions and the diffusion behavior. For in channel flow velocities of 50 mm.s(-1), patterns could persist on the order of millimeters to centimeters in the open volume. The most narrow diffusion zones with widths less than 10 microm (5-95% concentration change) were found some tens of micrometers out in the macroscopic container. We demonstrate that a 14-microm-diameter nearly spherical object (biological cell) attached to a micropipet can be moved from one solution environment to another by a lateral displacement of only 8 microm. The device is suitable for applications where the solution environment around a microscopic or nanoscopic sensor needs to be changed multiple times, i.e., in order to build layered structures, for obtaining binding isotherms, and kinetic information, for example, on ion channels, enzymes, and receptors as well as in applications where different loci on an object need to be exposed to different environments or where complex solution environments need to be created for studies of interfacial chemistry between two streaming layers.

Journal Article↗

PubMed2002

Multiple inequivalent metal-nucleotide coordination environments in the presence of the VO2+-inhibited nitrogenase iron protein: pH-dependent structural rearrangements at the nucleotide binding site.

Nitrogenase naturally requires adenosine nucleoside triphosphates and divalent metal cations for catalytic activity. Their energy of hydrolysis controls several mechanistic functions, most probably via separate structural conformers of the nitrogenase Fe protein. To characterize the ligand environment of the divalent metal in the ternary complex, with ADP or ATP and the Fe protein from Klebsiella pneumoniae, the hyperfine structures have been investigated by electron paramagnetic resonance (EPR) spectroscopy by substituting naturally occurring diamagnetic Mg(2+) by paramagnetic oxovanadium. This metal replacement leads to inhibition of nitrogenase activity. Moreover, depending on pH, two distinctly different VO(2+) EPR spectra are detected. At pH 7.4 each of the vanadyl EPR hyperfine lines is further split into two. This indicates that several spectroscopically distinguishable metal coordination environments coexist for VO(2+)-nucleotide chelate complexes in the presence of the reduced Fe protein. Overall, a total of at least three distinct local metal coordination environments have been identified. We report the EPR parameters for each of the disparate metal coordinations measured at different pH values with ADP and ATP bound. EPR spectra have also been recorded for the oxidized Fe protein showing essentially similar spectra to that of the reduced protein. The EPR parameters of VO-nucleotides in the presence of the Fe protein are consistent, for all metal coordination environments, with direct metal ligation by nucleotide phosphate groups and the formation of mononucleotide complexes. The nucleotide binding environment with the highest ligand field strength is compatible with a metal coordination structure that is also found in various G-proteins with GTP bound. No significant EPR line width change is detected after exchange into D(2)O buffer solution for any of the pH forms although differences exist between the pH forms. The missing difference between the EPR parameters in the presence of ADP or ATP suggests that there is little or no conformational rearrangement between these two forms; this contrasts with behavior of G-proteins that undergo substantial conformational changes upon hydrolysis. This could be related to the inhibition of nitrogenase by VO(2+).

Adenosine Diphosphate↗

PubMed2006

Occurrence of infected amoebae in cooling towers compared with natural aquatic environments: implications for emerging pathogens.

Many species of bacteria pathogenic to humans, such as Legionella, are thought to have evolved in association with amoebal hosts. Several novel unculturable bacteria related to Legionella have also been found in amoebae, a few of which have been thought to be causes of nosocomial infections in humans. Because amoebae can be found in cooling towers, we wanted to know whether cooling tower environments might enhance the association between amoebae and bacterial pathogens of amoebae in order to identify potential "hot spots" for emerging human pathogens. To compare occurrence of infected amoebae in natural environments with those in cooling towers, 40 natural aquatic environments and 40 cooling tower samples were examined. Logistic regression analysis determined variables that were significant predictors of the occurrence of infected amoebae, which were found in 22 of 40 cooling tower samples but in only 3 of the 40 natural samples. An odds ratio showed that it is over 16 times more likely to encounter infected amoebae in cooling towers than in natural environments. Environmental data from cooling towers and natural habitats combined revealed dissolved organic carbon (DOC) and pH were predictors of the occurrence of the pathogens, however, when cooling tower data alone were analyzed, no variables accounted for the occurrence. Several bacteria have novel rRNA sequences, and most strains were not culturable outside of amoebae. Such pathogens of amoebae may spread to the environment via aerosols from cooling towers. Studies of emerging infectious diseases should strongly consider cooling towers as a source of amoeba-associated pathogens.

Air Conditioning↗

PubMed2006

Artificial receptors that provides a preorganized hydrophobic environment: a biomimetic approach to dopamine recognition in water.

[structure: see text] The recognition of dopamine in water has been achieved with tripodal oxazoline-based artificial receptors, capable of providing a preorganized hydrophobic environment by rational design, which mimics a hydrophobic pocket predicted for a human D2 receptor. The receptors show an amphiphilic nature owing to the presence of hydrophilic sulfonate groups at the periphery of the tripodal oxazoline ligands, which seems to contribute in forming the preorganized hydrophobic environment. The artificial receptors recognized dopamine hydrochloride in water with reasonable selectivity among various organoammonium guests examined. The observed binding behavior of the receptors was explained by evoking guest inclusion in the preorganized hydrophobic pocket-like environment and not by simple ion-pairing interactions. The rationally predicted 1:1 inclusion binding mode was supported by binding studies such as with a reference receptor that cannot provide a similar binding pocket, Job and VT-NMR experiments, electrospray ionization mass analysis, and guest selectivity data. This study implies that an effective hydrophobic environment can be generated even from an acyclic, small molecular artificial receptor. Such a preorganized hydrophobic environment, as being utilized in biological systems, can be effectively used as a complementary binding force for the recognition of organoammonium guests such as dopamine hydrochloride in water.

Biomimetic Materials↗

PubMed2005

Nonradiative relaxation in thiophene-S,S-dioxide derivatives: the role of the environment.

The intramolecular radiative and nonradiative relaxation processes of three thiophene-S,S-dioxide derivatives with different molecular rigidity are investigated in different solutions and in inert matrix. We show that the fluorescence quantum efficiency and the relaxation dynamics are strongly dependent on the environment viscosity, whereas they are almost independent of the environment polarity. We demonstrate that this strong dependence is due to an environment dependent nonradiative decay rate, whereas no relevant variations of the radiative decay rate are observed. We demonstrate that the dipole coupling with the solvent does not provide an efficient nonradiative decay channel and that the S(n) - S(1) vibrational relaxation is very efficient in all of the molecules and for all of the investigated environments. Moreover first-principles time-dependent density-functional theory calculations in the correct, i.e., excited-state, molecular conformation, suggest that significant contributions of intersystem crossing to the triplet manifold can be excluded. We then conclude that the main nonradiative process determining the fluorescence quantum efficiency of this class of molecules is S(1) - S(0) internal conversion (IC). An explanation for the IC rate dependence in terms of the environment viscosity, molecular rigidity, S(1) - S(0) energy-gap, and molecular volume is presented.

Journal Article↗

PubMed2006

Electronic structure, ionization potential, and electron affinity of the enzyme cofactor (6R)-5,6,7,8-tetrahydrobiopterin in the gas phase, solution, and protein environments.

(6R)-5,6,7,8-Tetrahydrobiopterin (BH(4)) is a key cofactor involved in the electron transfer to the P(450) heme of nitric oxide synthase. We calculated the electronic structure of the neutral, cationic, and anionic forms of BH(4) in the gas phase, in solution (both dielectric and explicit water), and in the protein environment using density functional theory (B3LYP/6-31+G(d,p)). Subsequently, we derived the ionization potential (IP) and electron affinity (EA) of the cofactor in these chemical environments. We found that the electronic structure of BH(4) is susceptible to the presence of an external electric field and that conformational changes in the structure of BH(4) alone do not affect its electronic structure significantly. In the gas phase, water, and protein environments neutral BH(4) is the most stable species, while in the dielectric environment the anion becomes the most stable species. The IP of BH(4) in the protein environment is about half of that in the gas phase, and its EA is about 5 times smaller than that in the gas phase. Our results indicate that changes in the external electric field created by moving charged amino acid residues around BH(4) may lead to configurations that have the BH(4) ion as stable as or more stable than the neutral form, thus facilitating the electron transfer.

Algorithms↗

PubMed2003

Shiftwork and environment as interactive predictors of work perceptions.

Evidence suggests that the work environment may play a role in the elevated risk of adverse health outcomes among shiftworkers compared with dayworkers. Perceived work environment measures (physical stressors, job demand, job control, skill discretion, supervisor support, and safety perceptions) from UK oil industry personnel (N=1,867) were analyzed in relation to shiftwork (day/night rotation vs daywork) and objective work environment (onshore vs offshore). Age, education, job type, and negative affectivity were also included. The Environment * Shiftwork interaction was significant in multivariate tests and in 5 of the 6 univariate analyses. Onshore, shiftworkers perceived their environment significantly less favorably than dayworkers, but differences were less marked offshore. Results are discussed in relation to the demand-control-support model of work stress.

Adolescent↗

PubMed2006

Employing dynamical and chemical processes for contaminant mixtures outdoors to the indoor environment: the implications for total human exposure analysis and prevention.

There are many physical and chemical processes that affect the accumulation of outdoor pollutants. In recent years some of the information and concepts previously ascribed to outdoor pollution has been found to be useful in examining indoor dynamic and chemical processes. Further, becau se of the confining nature of the indoor environment, processes such as the "grasshopper effect" can lead to sustained higher levels of semivolatile chemicals indoors and affect multiroute (inhalation, dermal, incidental dietary, and nondietary ingestion) exposures. Such processes can also lead to a complex mixture of both semivolatile and volatile compounds in indoor air and on surfaces or within objects. This article specifically examines the above in combination with another indoor issue, indoor chemistry, and places the results into a context that can be used to evaluate (1) multipollutant cumulative or aggregate exposures and risks indoors, (2) exposure reduction strategies that can create healthy indoor environments. It is not a review of the entire field of the indoor environment or indoor air or the indoor environment, which has been covered in numerous volumes and reports. The complexities of the scientific issues are discussed by also placing them into our traditional approaches outdoor and indoor to pollution management, to indicate the difficulty in establishing the exposures that require mitigation or prevention. Further, some emerging issues are discussed as well as how to specifically address long-term single or multiroute exposures to semivolatile compounds within the "Total Indoor Environment."

Air Pollutants↗

PubMed2000

Farm environment in childhood prevents the development of allergies.

BACKGROUND: A protective effect of infections in early life might explain the firmly reported finding of an inverse association between atopic disorders and large sibships. OBJECTIVE: To study the effect of childhood farm, rural non-farm and urban environment, as well as family size and other factors on the occurrence of asthma, wheezing and atopic disorders up to young adulthood. METHODS: Data on lifetime prevalence of physician-diagnosed asthma, allergic rhinitis and/or allergic conjunctivitis, atopic dermatitis, as well as self-reported episodic wheezing from 10 667 Finnish first-year university students aged 18-24 years were collected by a postal questionnaire. Associations of lifetime prevalence of the diseases with living on a farm, in a rural non-farm and urban environment during childhood were estimated by logistic regression analysis. Adjustment was made for potential confounding by gender, parental atopy, parental education, number of older siblings, day care outside the home and passive smoking. RESULTS: The childhood farm environment independently reduced the risk for physician-diagnosed allergic rhinitis and/or allergic conjunctivitis (adjusted odds ratio 0.63, 95% CI 0.50-0.79, P < 0.001), and for diagnosed asthma and episodic wheezing analysed together (OR 0.71, 95% CI 0.54-0.93, P < 0.05), but not for atopic dermatitis during lifetime. Urban childhood environment did not show independent increased risk when compared with rural non-farm residence. The inverse association of sibship size with the occurrence of allergic rhinitis and/or allergic conjunctivitis was found among subjects with one (OR 0.86, 95% CI 0.77-0.96, P < 0.01) or at least four older siblings (OR 0.47, 95% CI 0.26-0.84, P < 0.05). CONCLUSION: Childhood farm environment seems to have a protective effect against allergic rhinitis and/or conjunctivitis, and more weakly against asthma and wheezing irrespective of family size. Environmental exposure to immune modulating agents, such as environmental mycobacteria and actinomycetes, favouring manifestation of a nonatopic phenotype could explain the finding.

Adolescent↗

PubMed2004

Patient-friendly hospital environments: exploring the patients' perspective.

OBJECTIVE: To investigate the perceptions and attitudes of patients to the built environments of NHS Trust hospitals, in order to inform design excellence so as to make future hospitals places and spaces responsive to patient needs. DESIGN: An exploratory study of patients perceptions based on qualitative semi-structured personal interviews. SETTING AND PARTICIPANTS: Fifty one-to-one interviews held with hospital in-patients across the four directorates of surgery, medicine, care of the elderly and maternity at Salford Royal Hospitals NHS Trust, Salford, UK. RESULTS: The research found that there was much similarity in the priorities, issues and concerns raised by patients in each of the four directorates. Patients perceived the built environment of the hospital as a supportive environment. Their accounts in each area pointed to the significance of the factors that immediately impacted on them and their families. Patients identified having a need for personal space, a homely welcoming atmosphere, a supportive environment, good physical design, access to external areas and provision of facilities for recreation and leisure. Responses suggest that patient attitudes and perceptions to the built environment of hospital facilities relates to whether the hospital provides a welcoming homely space for themselves and their visitors that promotes health and wellbeing. CONCLUSIONS: The findings have important implications for capital development teams, clinical staff, managers and NHS Estates personnel. Although the study has immediate relevance for Salford Royal Hospitals Trust, findings and recommendations reported provide NHS Estates and other relevant stakeholders with evidence-based knowledge and understanding of patients' perceptions and expectations of and preferences for particular facilities and estates provision in NHS hospitals.

Adult↗