PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “built environment”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 325 records · Page 18Linked to original sources
PubMed1992

HomeLog: long-term recording of infant temperature, respiratory and cardiac signals in the home environment.

There is increasing evidence that overheating is a contributing factor for some cot deaths. The authors' hypothesis is that infant thermoregulation is closely related to respiratory control. HomeLog is a system built to investigate the developing thermal, respiratory and cardiac behaviour of infants in the home environment over several weeks. HomeLog is based on a modified laptop computer. Signals recorded include body temperature (from rectal and various skin sites), ambient temperature, thoracic impedance, abdominal movement and electrocardiogram (ECG). Continuous night-time recordings have been made for up to 6 weeks from infants between 1 and 4 months of age, in their own cots, in their own homes. Various time and frequency domain analyses of the breathing and temperature data have been developed. Analysis of breath rate variability and of body temperature fluctuations has confirmed sleep/wake changes. In addition, a periodic oscillation of body temperature every 1-2 h has been found, which closely matches oscillations of breath rate variability.

Apnea↗
PubMed1996

Carbon dioxide exchange of lettuce plants under hypobaric conditions.

Growth of plants in a Controlled Ecological Life Support System (CELSS) may involve the use of hypobaric pressures enabling lower mass requirements for atmospheres and possible enhancement of crop productivity. A controlled environment plant growth chamber with hypobaric capability designed and built at Ames Research Center was used to determine if reduced pressures influence the rates of photosynthesis (Ps) and dark respiration (DR) of hydroponically grown lettuce plants. The chamber, referred to as a plant volatiles chamber (PVC), has a growing area of about 0.2 m2, a total gas volume of about 0.7 m3, and a leak rate at 50 kPa of <0.1%/day. When the pressure in the chamber was reduced from ambient to 51 kPa, the rate of net Ps increased by 25% and the rate of DR decreased by 40%. The rate of Ps increased linearly with decreasing pressure. There was a greater effect of reduced pressure at 41 Pa CO2 than at 81 Pa CO2. This is consistent with reports showing greater inhibition of photorespiration (Pr) in reduced O2 at low CO2 concentrations. When the partial pressure of O2 was held constant but the total pressure was varied between 51 and 101 kPa, the rate of CO2 uptake was nearly constant, suggesting that low pressure enhancement of Ps may be mainly attributable to lowered partial pressure of O2 and the accompanying reduction in Pr. The effects of lowered partial pressure of O2 on Ps and DR could result in substantial increases in the rates of biomass production, enabling rapid throughput of crops or allowing flexibility in the use of mass and energy resources for a CELSS.

Air Pressure↗
PubMed2005

Magnetic properties and crystal structure of a one-dimensional phase of tetrakis(mu2-benzoato-O,O')-bis(dimethyl sulfoxide)dicopper(II).

A new crystalline polymorphic phase of tetrakis(mu2-benzoato-O,O')-bis(dimethyl sulfoxide)dicopper(II) was obtained by direct synthesis, in space group P2(1)/n. The copper coordination is in a slightly distorted square pyramidal geometry with an intramolecular Cu...Cu distance of 2.6494(8) angstroms. The Cu-O distances of the two copper in a dimer are different, giving different chemical environments for each Cu ion. The crystal structure is built up of well-separated stacking columns oriented along the b-axis, with units uniformly spaced, producing a one-dimensional (1-D) zigzag chain through Cu(II)-S...S-Cu(II) interdimer interactions [S...S separation: 3.975(2) angstroms]. Magnetization measurements in the range 2-300 K indicate two magnetic orderings, at low temperature (T < 10 K) a weak ferromagnetic ordering is observed, and above this temperature an antiferromagnetic behavior takes place. ESR spectra at 300 and 77 K of a polycrystalline sample show the characteristic signal of zero-field with D = 0.354 cm(-1), consistent with a ferromagnetic Cu...Cu exchange interaction at low temperature.

Journal Article↗
PubMed2006

Homology model of human retinoic acid metabolising enzyme cytochrome P450 26A1 (CYP26A1): active site architecture and ligand binding.

Homology models of cytochrome P450 RA1 (CYP26A1) were constructed using three human P450 structures, CYP2C8, CYP2C9 and CYP3A4 as templates for the model building. Using MOE software the lowest energy CYP26A1 model was then assessed for stereochemical quality and side chain environment. Further active site optimisation of the CYP26A1 model built using the CYP3A4 template was performed by molecular dynamics to generate a final CYP26A1 model. The natural substrate, all-trans-retinoic acid (atRA), and inhibitor R 15866, were docked into the model allowing further validation of the active site architecture. Using the docking studies structurally and functionally important residues were identified with subsequent characterisation of secondary structure. Multiple hydrophobic interactions, including the side chains of TRP112, PHE299, PHE222, PHE84, PHE374 and PRO371, are important for binding of atRA and R115866. Additional hydrogen bonding interactions were noted as follows: atRA-- C==O of the atRA carboxylate group and ARG86; R115866--benzothiazole nitrogen and the backbone NH of SER115.

Alcohol Dehydrogenase↗
PubMed2002

Optically stimulated luminescent glass optical fibre dosemeter.

An optical fibre radiation dosemeter has been developed that utilises optically stimulated luminescence and scintillation to provide independent, remote, real-time dose measurements. The radiation sensitive element consists of a 1 mm long, 0.4 mm diameter piece of copper-ion-doped fused quartz that is attached to a 1 m length of commercial optical fibre. The dosemeter probe is 0.6 mm in diameter and is flexible enough to be used in standard medical catheters for internal radiation dose measurements. A four-channel dosemeter system has been built and characterised under conditions typical of a radiotherapy environment. The device exhibits a linear response over the range of doses from 0.01 Gy to 10 Gy. The dosemeter responds identically to both electrons and photons in the range from 4 to 20 MV and the calibration was retained to within +/-2% over a period of 4 weeks. The fibre dosemeter has been used successfully to verity doses received by three patients receiving radiotherapy treatments.

Calibration↗
PubMed2004

Computational protein design is a challenge for implicit solvation models.

Increasingly complex schemes for representing solvent effects in an implicit fashion are being used in computational analyses of biological macromolecules. These schemes speed up the calculations by orders of magnitude and are assumed to compromise little on essential features of the solvation phenomenon. In this work we examine this assumption. Five implicit solvation models, a surface area-based empirical model, two models that approximate the generalized Born treatment and a finite difference Poisson-Boltzmann method are challenged in situations differing from those where these models were calibrated. These situations are encountered in automatic protein design procedures, whose job is to select sequences, which stabilize a given protein 3D structure, from a large number of alternatives. To this end we evaluate the energetic cost of burying amino acids in thousands of environments with different solvent exposures belonging, respectively, to decoys built with random sequences and to native protein crystal structures. In addition we perform actual sequence design calculations. Except for the crudest surface area-based procedure, all the tested models tend to favor the burial of polar amino acids in the protein interior over nonpolar ones, a behavior that leads to poor performance in protein design calculations. We show, on the other hand, that three of the examined models are nonetheless capable of discriminating between the native fold and many nonnative alternatives, a test commonly used to validate force fields. It is concluded that protein design is a particularly challenging test for implicit solvation models because it requires accurate estimates of the solvation contribution of individual residues. This contrasts with native recognition, which depends less on solvation and more on other nonbonded contributions.

Algorithms↗
PubMed1982

An approach to clinical magnetocardiology.

Magnetocardiograms (MCGs) of normal human subjects and patients with various heart diseases and of fetuses (fetal magnetocardiogram, FMCG) were recorded using a SQUID magnetometer with a built-in second derivative gradiometer in a magnetically unshielded environment. MCGs and ECGs in this study were taken simultaneously at the same precordial chest positions (V1 approximately V6). The following results were obtained: (1) The waves of MCG showed a variety of changes which can never be detected in ECGs. (2) Clear FMCGs could be recorded without being overlapped by MCG of the mother. (3) In MCGs from a patient with complete A-V block, there was a secondary pacemaker spike which was presumably related to ventricular depolarization. (4) There were two kinds of characteristic changes with time in MCGs after onset of anterior myocardial infarction, which could be confirmed in experiments with dogs. Thus, the results obtained so far indicate a bright future of magnetocardiology in clinical medicine.

Adult↗
PubMed1994

Independent segregation of a hyperactive hypothalamic-hypophyso-adrenal axis and a reduced behavioural reactivity in pigs.

When compared to European Large White, Chinese Meishan pigs have high levels of circulating ACTH and cortisol, and a reduced behavioural reactivity in various challenging situations such as exposure to a novel environment, two characteristic features of depression. We investigated whether this association is genetically built in or whether these psychobiological characteristics are fortuitously associated. Six-week-old piglets from the segregating F2 crosses between the Meishan and Large White breeds were studied in a standardised protocol of novel environment exposure. As expected from the genetic diversity, a wide range of variation was recorded for behavioural reactivity (locomotion, vocalisations). ACTH, cortisol, and glucose were measured in blood samples taken immediately before the test and at the end of the session. Again these measures varied considerably between animals, and the continuous distribution of the scores suggested that they are under control of numerous genes. Furthermore, no correlation could be found between neuroendocrine and behavioural measures. This result demonstrates that the association between high ACTH/corticosteroid levels and a low behavioural reactivity is not genetically controlled.

Adaptation, Psychological↗
PubMed2006

No evidence for UV-based nest-site selection in sticklebacks.

BACKGROUND: Nests are built in various animal taxa including fish. In systems with exclusive male parental care, the choice of a nest site may be an important component of male fitness. The nest site may influence male attractiveness as a mate, and male, embryo, and juvenile survival probabilities. Reproductively active three-spined stickleback males establish and defend a territory in which they build a nest. Territories can differ remarkably in qualities that influence male and female reproductive success like predation risk or abiotic factors such as dissolved oxygen concentration or lighting conditions. The latter may be important because in sticklebacks the extended visual capability into the ultraviolet (UV) wave range plays a role in female mate choice. Males are thus expected to be choosy about the habitat in which they will build their nest. RESULTS: We tested nest-site choice in male three-spined sticklebacks with respect to different UV lighting conditions. Reproductively active males were given the simultaneous choice to build their nest either in an UV-rich (UV+) or an UV-lacking (UV-) environment. Males exhibited no significant nest-site preferences with respect to UV+ or UV-. However, larger males and also heavier ones completed their nests earlier. CONCLUSION: We found that UV radiation as well as differences in luminance had no influence on nest-site choice in three-spined sticklebacks. Males that built in the UV-rich environment were not different in any trait (body traits and UV reflection traits) from males that built in the UV-poor environment. There was a significant effect of standard length and body mass on the time elapsed until nest completion in the UV experiment. The larger and heavier a male, the faster he completed his nest. In the brightness control experiment there was a significant effect only of body mass on the duration of nest completion. Whether nest building preferences with respect to UV lighting conditions are context dependent needs to be tested for instance by nest-site choice experiment under increased predation risk.

Journal Article↗
PubMed1987

Continuous flow electrophoretic separation of proteins and cells from mammalian tissues.

A new continuous flow electrophoretic separator for cells and macromolecules was built and tested in laboratory experiments and in the microgravity environment of space flight. Buffer flows upward in a 120-cm long flow chamber, which is 6 cm wide X 1.5 mm thick in the laboratory version and 16 cm wide X 3.0 mm thick in the microgravity version. Electrophoretic subpopulations are collected in 197 fractions spanning 16 cm at the upper end of the chamber. The electrode buffer is recirculated through front and back cooling chambers, which are also electrode chambers. Ovalbumin and rat serum albumin were used as test proteins in resolution and throughout tests; resolution of these two proteins at 25% total w/v concentration in microgravity was the same as that found at 0.2% w/v concentration in the laboratory. Band spreading caused by Poiseuille flow and conductance gaps was evaluated using polystyrene microspheres in microgravity, and these phenomena were quantitatively the same in microgravity as in the laboratory. Rat anterior pituitary cells were separated into subpopulations enriched with cells that secrete specific hormones; growth-hormone-secreting cells were found to have high electrophoretic mobility, whereas prolactin-secreting cells were found to have low electrophoretic mobility. Cultured human embryonic kidney cells were separated into several electrophoretic subfractions that produced different plasminogen activators; a medium-high-mobility subpopulation and a medium-low-mobility subpopulation each produced a different molecular form of urokinase, whereas a high- and an intermediate-mobility subpopulation produced tissue plasminogen activator. Canine pancreatic islets of Langerhans cells were separated into subpopulations, which, after reaggregation into pseudoislets, were found to be enriched with cells that secrete specific hormones; insulin-secreting beta cells were found in lowest mobility fractions, whereas glucagon-secreting alpha cells were found in the highest mobility fractions. Results of particle electrophoresis experiments were comparable in microgravity and in the laboratory, since cell densities that overloaded the carrier buffer (resulting in zone sedimentation) were avoided, and a 500-fold increase in protein throughput was achieved without compromising resolution in microgravity.

Animals↗
PubMed2000

Study of cosmic rays and light flashes on board Space Station MIR: the SilEye experiment.

The SilEye experiment aims to study the cause and processes related to the anomalous Light Flashes (LF) perceived by astronauts in orbit and their relation with Cosmic Rays. These observations will be also useful in the study of the long duration manned space flight environment. Two PC-driven silicon detector telescopes have been built and placed aboard Space Station MIR. SilEye-1 was launched in 1995 and provided particles track and LF information; the data gathered indicate a linear dependence of FLF(Hz) ( 4 2) 10(3) 5.3 1.7 10(4) Fpart(Hz) if South Atlantic Anomaly fluxes are not included. Even though higher statistic is required, this is an indication that heavy ion interactions with the eye are the main LF cause. To improve quality and quantity of measurements, a second apparatus, SilEye-2, was placed on MIR in 1997, and started work from August 1998. This instrument provides energetic information, which allows nuclear identification in selected energy ranges; we present preliminary measurements of the radiation field inside MIR performed with SilEye-2 detector in June 1998.

Cosmic Radiation↗
PubMed2000

A general 13C NMR spectrum predictor using data mining techniques.

A general-case neural network model for 13C NMR spectrum prediction (estimation) was built from more than 8,300 carbon atoms having various environments. Building the model from the data set required a few weeks' work using commercial software. Average deviation on test data is ca. 4 ppm. There is no limit on molecule complexity. Estimation error does not depend on molecule size or complexity. The emphasis is on the data, the method and the results, not on the processes that take place inside the modelling software. Advantages, disadvantages and peculiarities of neural network-based data modelling ("data mining") are described at length. The differences in data handling between the data mining approach and traditional statistical modelling techniques are discussed and illustrated in detail. The spectrum predictor is available from PMSI at no charge.

Carbon Isotopes↗
PubMed1977

[Problems of aged people in rural regions of the Swiss Canton St. Gall (author's transl)].

Based on the structure of the mountain population, the living conditions of the aged (in rural communities 11-17% are older than 65) are shown. By public planning and cooperation of private organizations a material security of the aged has been strived after and mostly reached in the last 15 years--with the tendency to leave the aged in his own house or at least in the environment of his native village. Homes for the aged were built--if possible in every community--on the basis of 50 beds in a home for the aged and 35 beds in a nursing home for 10.000 inhabitants (83% in nursing homes an 17% in acute hospitals with geriatric departments). The individual help for the aged: activation by offering common institutions, ingenious activity, non-public advice offices, household help is deduced and the planning for the coming decade mentionned.

Aged↗
PubMed1990

[Frequency of psychiatric admissions from recently built satellite areas (concrete buildings) in the western district of Copenhagen].

Scandinavian investigations have demonstrated that the extent of mental disturbances is related to the nature of the district concerned. Young satellite districts, concrete built up areas in the periphery of large cities have been pointed out as high risk regions. Environments with poor resources, dominated by social disintegration increase the risk of mental disturbances in persons who are already poorly integrated. Four satellite building sites which were built within the past 25 years in the westerly part of Copenhagen were investigated for the frequency of inpatient admissions in the regional psychiatric department in 1985. 23% of all the admissions occur from these regions where 12% of the basic population lives. The majority of the admissions occur partly from the oldest of these regions built in the nineteen sixties and also from the two youngest regions built at the end of the nineteen seventies. The same pattern was found for the main diagnoses: character disturbances and drug addiction while the diagnosis of schizophrenia is commonest in the two youngest regions. Socio-economical data which suggests social disintegration in these districts is quoted. Purposeful social-psychiatric efforts in the high risk districts are necessary. Mental hygienic requirements should be taken into consideration in planning new residential districts.

Adolescent↗
PubMed2000

Neural correlates of topographic mental exploration: the impact of route versus survey perspective learning.

There are two major sources of information to build a topographic representation of an environment, namely actual navigation within the environment (route perspective) and map learning (survey perspective). The aim of the present work was to use positron emission tomography (PET) to compare the neural substrate of the topographic representation built from these two modes. One group of subjects performed a mental exploration task in an environment learned from actual navigation (mental navigation task). Another group of subjects performed exploration in the same environment learned from a map (mental map task). A right hippocampal activation common to both mental navigation and mental map tasks was evidenced and may correspond the neural substrate of a "dual-perspective" representation. The parahippocampal gyrus was additionally activated bilaterally during mental navigation only. These results suggest that the right hippocampus involvement would be sufficient when the representation incorporates essentially survey information while the bilateral parahippocampal gyrus would be involved when the environment incorporates route information and includes "object" landmarks. The activation of a parietofrontal network composed of the intraparietal sulcus, the superior frontal sulcus, the middle frontal gyrus, and the pre-SMA was observed in common for both mental navigation and mental map and is likely to reflect the spatial mental imagery components of the tasks.

Adult↗
PubMed2005

[Digital teaching archive. Concept, implementation, and experiences in a university setting].

Film-based teaching files require a substantial investment in human, logistic, and financial resources. The combination of computer and network technology facilitates the workflow integration of distributing radiologic teaching cases within an institution (intranet) or via the World Wide Web (Internet). A digital teaching file (DTF) should include the following basic functions: image import from different sources and of different formats, editing of imported images, uniform case classification, quality control (peer review), a controlled access of different user groups (in-house and external), and an efficient retrieval strategy. The portable network graphics image format (PNG) is especially suitable for DTFs because of several features: pixel support, 2D-interlacing, gamma correction, and lossless compression. The American College of Radiology (ACR) "Index for Radiological Diagnoses" is hierarchically organized and thus an ideal classification system for a DTF. Computer-based training (CBT) in radiology is described in numerous publications, from supplementing traditional learning methods to certified education via the Internet. Attractiveness of a CBT application can be increased by integration of graphical and interactive elements but makes workflow integration of daily case input more difficult. Our DTF was built with established Internet instruments and integrated into a heterogeneous PACS/RIS environment. It facilitates a quick transfer (DICOM_Send) of selected images at the time of interpretation to the DTF and access to the DTF application at any time anywhere within the university hospital intranet employing a standard web browser. A DTF is a small but important building block in an institutional strategy of knowledge management.

Computer-Assisted Instruction↗
PubMed2001

Golf course development in a major tourist destination: implications for planning and management.

The planning and design of golf course developments is influenced by many factors. This paper focuses on the environmental ramifications of insufficient or lack of compliance with standard environmental and economic planning practices. Specifically, it looks at a tourist destination location that was under the influence of extensive land development and investment speculation. The Gold Coast in Australia was the focal point for large overseas investment due to changes in government legislation regarding foreign investment. Due to the economic climate in the second half of the 1980s many golf course resort developments were built, approved, or planned. Many of these circumvented normal business and environment planning processes. The result has been a dangerous concentration of golf facilities in environmentally sensitive areas and an oversupply of golf facilities. Both of these matters are discussed in terms of the general planning process and the potential economic and environmental impacts to the Gold Coast and similar destinations in other parts of the world.

Commerce↗