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Results for “Environment, Controlled”

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PubMed1976

Advancement to independent living: a model behavioral program for the intermediate care of adults with behavioral and emotional problems.

This article describes and evaluates the treatment effectiveness of a behaviorally oriented intermediate day-care clinic for adults with psychiatric disturbances. The goals of the program included reducing the number of psychiatric hospital admissions and readmissions, providing a community-based controlled environment to assist patients in the modification of specific problem behavior, improving interpersonal relations with "significant others" in the natural environment, teaching patients how to use community resources, and preparing them for employment and/or continued outpatient treatment. The program was structured so that patients advance through a series of four achievement levels for a variety of extrinsic and intrinsic reinforcers. While in the program, patients were introduced to available community resources, and were gradually phased into follow-up services. Results showed that 79% of all patients thus far treated partially, if not completely, advanced through the levels. There was also a high probability that a patient would advance from any given level. Outside-clinic behavior showed sustained improvement, with the authors concluding that the day-care clinic offered promise for the future.

Adult↗

PubMed2026

Electromagnetic Radiation Stimulated Learning in Perovskite Nickelates.

Biological plasticity refers to the ability of synapses to strengthen or weaken over time. These adaptive properties play a fundamental role in learning and memory, spanning many orders of magnitude in timescales. Short-term plasticity (STP) arises from rapid correlative activity, while long-term plasticity (LTP) is governed by slower biochemical processes. Here, we investigate electromagnetically driven relaxation dynamics in perovskite nickelate thin films as an analogue of biological learning behaviors. By comparing radio frequency (RF), infrared (IR), visible, and ultraviolet (UV) radiation as stimuli, we find that RF excitation primarily induces STP, while visible and IR illumination lead to reversible relaxation on behavioral timescales. In contrast, UV illumination results in persistent, non-thermal changes in conductivity over extended timescales. Notably, UV-exposed nickelate films exhibit glass-like dynamics, characterized by stretched exponential relaxation and aging phenomena. The films display habituation to repeated stimuli, along with sensitization and spontaneous recovery under controlled environments. A minimal dynamical systems model captures key qualitative features of the UV-induced resistance changes. Our results demonstrate that electromagnetic frequency enables multi-timescale relaxation spanning nearly nine orders of magnitude, suggesting perovskite nickelates as promising platforms for adaptive optoelectronic hardware and for linking computational neuroscience with emerging quantum technologies.

electromagnetic radiation↗

PubMed2002

Patterns of lateralized hand use in an arboreal primate, Simias concolor.

Studies of hand use in nonhuman primates suggest that several species exhibit hand preferences for a variety of tasks. The majority of studies, however, focus on the lateralized hand use of captive nonhuman primate populations. Although captive settings offer a more controlled environment for assessing hand preferences, studies of wild populations provide important insights into how handedness is affected by natural environmental conditions and thus potential insights into the evolution of handedness. To investigate handedness in a population of wild nonhuman primates, we studied patterns of lateralized hand use during feeding in four simakobu monkeys (Simias concolor), an arboreal species inhabiting the Mentawai Islands, Indonesia. Our data show that individual variation in hand preferences for feeding existed among our study animals. In addition, each simakobu expressed a significant hand preference for supporting itself on a branch during feeding, an uncoordinated bimanual task. This bias was most prevalent when the branch used for support was a main branch rather than a terminal branch. When both hands were employed in a coordinated bimanual feeding activity (bimanual manipulation), only two subjects showed a significant bias for feeding. Our data suggest that these individuals are more likely to express significant hand preferences when feeding from stable, rather than precarious, positions within the canopy.

Animals↗

PubMed2005

Proximity and estrous synchrony in Mahale chimpanzees.

Since McClintock [Nature 229:244-255, 1971] first reported menstrual synchrony in women, a number of studies have reported similar phenomena. Many researchers have suggested that one of the proximate factors leading to synchrony is spatial proximity among females (e.g., close friends or roommates). However, most studies on menstrual synchrony have been conducted in limited spaces, and it remains to be determined whether controlled environments, such as those used in experiments, actually exist in the wild. In this study, we analyzed the relationship between proximity and estrous synchrony using data from wild female chimpanzees at Mahale, Tanzania. In the cycling females, we observed two pairs that spent a large amount of time together. We compared the estrous synchrony indices (ESIs) between these two pairs and the other females. Our results showed that the ESIs of the high-proximity pairs did not differ from those of other pairs. .

Animals↗

PubMed2002

Determination of safety distance limits for a human near a cellular base station antenna, adopting the IEEE standard or ICNIRP guidelines.

This paper investigates the minimum distance for a human body in the near field of a cellular telephone base station antenna for which there is compliance with the IEEE or ICNIRP threshold values for radio frequency electromagnetic energy absorption in the human body. First, local maximum specific absorption rates (SARs), measured and averaged over volumes equivalent to 1 and to 10 g tissue within the trunk region of a physical, liquid filled shell phantom facing and irradiated by a typical GSM 900 base station antenna, were compared to corresponding calculated SAR values. The calculation used a homogeneous Visible Human body model in front of a simulated base station antenna of the same type. Both real and simulated base station antennas operated at 935 MHz. Antenna-body distances were between 1 and 65 cm. The agreement between measurements and calculations was excellent. This gave confidence in the subsequent calculated SAR values for the heterogeneous Visible Human model, for which each tissue was assigned the currently accepted values for permittivity and conductivity at 935 MHz. Calculated SAR values within the trunk of the body were found to be about double those for the homogeneous case. When the IEEE standard and the ICNIRP guidelines are both to be complied with, the local SAR averaged over 1 g tissue was found to be the determining parameter. Emitted power values from the antenna that produced the maximum SAR value over 1 g specified in the IEEE standard at the base station are less than those needed to reach the ICNIRP threshold specified for the local SAR averaged over 10 g. For the GSM base station antenna investigated here operating at 935 MHz with 40 W emitted power, the model indicates that the human body should not be closer to the antenna than 18 cm for controlled environment exposure, or about 95 cm for uncontrolled environment exposure. These safe distance limits are for SARs averaged over 1 g tissue. The corresponding safety distance limits under the ICNIRP guidelines for SAR taken over 10 g tissue are 5 cm for occupational exposure and about 75 cm for general-public exposure.

Cell Phone↗

PubMed2004

A single magnetic field exposure system for sequential investigation of real time and downstream cellular responses.

To be able to correlate real time membrane potential or ion flux changes with further downstream gene transcription responses due to extremely low frequency (ELF) electromagnetic field (EMF) exposure, we devised an experimental system consisting of a pair of symmetric circular coils. This system can be used on an inverted microscope stage (real time signaling) as well as inside controlled environment incubators (gene transcription end points). The system includes a unique, custom made switch box for blinding the experimental staff and a power amplifier. We report herein the design and characterization of the system with respect to parameters considered important in in vitro ELF-EMF exposure studies, including linear magnetic field distribution, compensation for microscope objective lens interference, heating effects of the coils, and harmonic content of the signals.

Cell Culture Techniques↗

PubMed1980

Microwave radiation (2450 MHz) alters the endotoxin-induced hypothermic response of rats.

The parenteral administration of bacterial endotoxin to rats causes a hypothermia that is maximal after approximately 90 minutes. When endotoxin-injected rats were held in a controlled environment at 22 degree C and 50% relative humidity and exposed for 90 minutes to microwaves (2450 MHz, CW) at 1 mW/cm2, significant increases were observed in body temperature compared with endotoxin-treated, sham-irradiated rats. The magnitude of the response was related to power density (10 mW/cm2 greater than 5 mW/cm2 greater than 1 mW/cm2). Saline-injected rats exposed for 90 minutes at 5 mW/cm2 (specific absorption rate approximately 1.0 mW/g) showed no significant increase in body temperature compared with saline-injected, sham-irradiated rats. The hypothermia induced by endotoxin in rats was also found to be affected by ambient temperature alone. Increases in ambient temperature above 22 degree C in the absence of microwaves caused a concomitant increase in body temperature. This study reveals that subtle microwave heating is detectable in endotoxin-treated rats that have impaired thermoregulatory capability. These results indicate that the interpretation of microwave-induced biological effects observed in animals at comparable rates and levels of energy absorption should include a consideration of the thermogenic potential of microwave.

Acclimatization↗

PubMed1993

Temporal bisection in rats: the effects of high-peak-power pulsed microwave irradiation.

The effects of high-peak-power, pulsed microwaves on a time perception and discrimination task were studied in rats. Exposures were performed with the TEMPO exposure system, which produces an 80 nanosecond pulse with peak-power levels in excess of 700 megawatts. The ability to expose animals to such fields within a controlled environment is unique. As determined by calorimetry, a maximal, whole-body-averaged, specific-absorption rate of 0.072 W/kg was produced. Thus exposures were well below a recommended SAR limit of 0.4 W/kg. Power levels of transmitted microwaves were varied over a 50 dB range to obtain ascending and descending dose-response functions for each of the behavioral measures. Measures of time perception, response bias, and total trials did not change with power level. Dose-response effects were observed for discriminability (ability to distinguish between durations), session time, and trial completions (null responses, failures to respond on a trial). Covarying sound and X-ray exposures produced by TEMPO did not reliably correlate with the observed microwave effects. The observation of repeatable dose-response effects on discriminability and null responses indicates that the microwave exposures were affecting cognitive function in the rats, particularly the decision-making process.

Animals↗

PubMedDate not supplied

Expression of firefly luciferase gene in Erwinia amylovora.

In this study we describe an efficient stable genetic transformation of the phytopathogenic bacterium Erwinia amylovora using a recombinant expression vector encoding the firefly luciferase gene of Photinus pyralis, which is further controlled by IPTG-inducible promoter. Stably transformed E. amylovora cells maintain the same infectivity as the wild-type strain and, after induction with IPTG, produce luciferase. Luminescence produced by the action of luciferase on an exogenous substrate was easily detectable by a simple and rapid bioluminescent assay (BL). The transformed E. amylovora strain maintains the same high emission level, even after passage in pears, until about 15 days post-infection. Our findings therefore show that the luciferase assay can be conveniently used to follow the bacterial movement in plant tissue and its dissemination in controlled environments.

Animals↗

PubMed2006

Improved development of human embryonic stem cell-derived embryoid bodies by stirred vessel cultivation.

Human embryonic stem cells (hESCs) represent an important resource for novel cell-based regenerative medical therapies. hESCs are known to differentiate into mature cells of defined lineages through the formation of embryoid bodies (EBs) which are amenable to suspension culture for several weeks. However, EBs derived from hESCs in standard static cultures are typically non-homogeneous, leading to inefficient cellular development. Here, we systematically compare the formation, growth, and differentiation capabilities of hESC-derived EBs in stirred and static suspension cultures. A 15-fold expansion in total number of EB-derived cells cultured for 21 days in a stirred flask was observed, compared to a fourfold expansion in static (non-stirred) cultures. Additionally, stirred vessel mediated cultures have a more homogeneous EB morphology and size. Importantly, the EBs cultivated in spinner flasks retained comparable ability to produce hematopoietic progenitor cells as those grown in static culture. These results demonstrate the decoupling between EB cultivation method and EB-derived cells' ability to form hematopoietic progenitors, and will allow for improved production of scalable quantities of hematopoietic cells or other differentiated cell lineages from hESCs in a controlled environment.

Cell Culture Techniques↗

PubMed2004

Reversible collapse of brushlike macromolecules in ethanol and water vapours as revealed by real-time scanning force microscopy.

Environment-controlled scanning force microscopy allowed us to study adsorption and desorption of single poly(methacrylate)-graft-poly(n-butyl acrylate) brush molecules on mica in real time. The molecules transform reversibly from a two-dimensional, extended wormlike state to a compact globular state. The dynamics of the conformational transition was sufficiently slow in order to allow its observation by scanning force microscope in real time. The reversible transformation is effected by coadsorption of water or ethanol, the latter introduces the collapse. Adsorbing ethanol and water from the vapour atmosphere results in a change of the surface properties of mica, either favouring adsorption or desorption of the graft polymer. When the extended, tightly adsorbed poly(n-butyl acrylate) brush molecules are exposed to ethanol vapour, the macromolecules swell and contract to form compact globules. Exchanging the ethanol vapour to a humid atmosphere caused the molecules to extend again to a wormlike two-dimensional conformation. Coexistence of collapsed and extended strands within the same molecule indicates a single-molecule first-order transition in agreement with observations on Langmuir films previously reported.

Ethanol↗

PubMed1979

Functional organization of rat olfactory bulb analysed by the 2-deoxyglucose method.

The spatial patterns of activity elicited in the rat olfactory bulb under different odor conditions have been analysed using the 2-deoxyglucose (2DG) technique. Rats were injected with 14C-2DG, exposed to controlled environments of amyl acetate, camphor, cage air, dimethyl disulfide, and pure air and autoradiographs prepared by the method of Sokoloff. Amyl acetate was associated with regions of glomerular layer densities in the anterolateral and mid- to posteromedial parts of the bulbar circumference, as previously reported. The extents of the densities increased with increasing concentration. Camphor odor was associated with regions of increased density in the anterodorsal and mid- to posteromedial parts of the bulb. Exposure to cage air produced scattered densities in the posteromedial and posterolateral bulb. Exposure to dimethyl disulfide gave variable results. Pure air was associated with a minimal number of small dense foci. The results with amyl acetate, camphor and cage air suggest that patterns for different odors are distinguishably different but overlapping. The regions of activity are greatest in extent and density with the highest odor concentrations. These define the regions within which more restricted and isolated foci appear at lower concentrations. The results thus provide evidence for the specific role of spatial factors in the neural processing of odor quality and odor concentration.

Acetates↗

PubMed2007

Establishment and characterization of an immortomouse-derived odontoblast-like cell line to evaluate the effect of insulin-like growth factors on odontoblast differentiation.

Insulin-like growth factors (IGF-I and IGF-II) play important roles in regulating growth and differentiation of many different organs including teeth. The presence of these factors in the developing tooth has been demonstrated. In vitro studies using tooth explants grown in the presence of IGFs suggest that they promote differentiation of ameloblast and odontoblasts cells. This is achieved by inducing or repressing gene expression associated with these cells. Since some of the genes involved in tooth differentiation are expressed by both cells, to determine the effect of IGF on odontoblast cell differentiation we first need a cell line in which a controlled environment can be created. In this study, we report the establishment and characterization of an Immortomouse-derived odontoblast-like cell line. This conditional cell line can grow indefinitely under permissive conditions in the presence of INF-gamma at 33 degrees C, differentiate into odontoblast-like cells and produce a mineralized extracellular matrix when the INF-gamma is removed and cell maintained at 39 degrees C. Addition of exogenous IGFs to the media results in an accelerated production of a mineralized matrix. This is the result of increased transcription of genes associated with bone mineralization while down regulating genes associated with dentin formation like DSPP. This data suggest that IGFs induce dental papillae mesenchyme cells to produce a bone-like mineralized extracellular matrix.

Animals↗

PubMed1979

Analysis of nitrosamines in aqueous and biological fluids based on measurement of photochemically liberated nitrite.

A method is described for the analysis of nitrosamines in aqueous solution and in biological fluids (blood, plasma, and rat liver microsomal suspensions). The method is based on photochemical degradation of the nitrosamine in a controlled environment to yield the corresponding amine and nitrite ion, and the latter is subsequently used to form a chromophoric or fluorescent product. The analysis scheme is a modular three-component system consisting of a column to remove contaminating nitrite prior to photolysis, a photochemical reactor, and a chemical reactor. Additional modules are used to accommodate biological samples or large-volume (5--50 ml) aqueous samples. In this study, N-nitrosopyrrolidine, N-nitrosodimethylamine, and N,N-diethanolnitrosamine were utilized as substrates. Because of intersubstrate variability in the photochemical decomposition rate and overall nitrite yield, the structure (i.e., photochemical behavior) of the particular nitrosamine in the sample must be known prior to analysis. With a colorimetric readout, the sensitivity for analysis of N-nitrosopyrrolidine was 800 ng/ml for a 5-ml sample and the measurement precision was +/- 6% in the biological fluids. Fluorometric analysis improved sensitivity to 4 ng/ml with a precision of +/- 10% in biological media.

Animals↗

PubMed1987

Sizing of a vesicle drug formulation by quasi-elastic light scattering and comparison with electron microscopy and ultracentrifugation.

Quasi-elastic light scattering has been used for the sizing of a vesicle formulation. Porcine insulin was encapsulated in a vesicle preparation containing cholesterol, dipalmitoylphosphotidylcholine, digalactosyl digycerides, and dipalmitoylphosphotidylglycerol in a 40:40:15:5 ratio. The measurement requires less than 15 min to obtain mean size and distribution information and can be operated in a quality control environment. Advantages and limitations of quasi-elastic light scattering are described and this method is compared to electron microscopy and ultracentrifugation.

Chemistry, Pharmaceutical↗

PubMed2006

Metabolism, protein content, and in vitro embryonic development of goat cumulus-oocyte complexes matured with physiological concentrations of glucose and L-lactate.

No information is available concerning how the maturation environment controls the metabolism of goat oocytes. The objectives of this experiment were to: (1) Determine the concentrations of glucose, lactate, and pyruvate in caprine follicular fluid; and (2) Investigate the effects of physiological concentrations of glucose and lactate in the in vitro maturation (IVM) medium on the metabolism (glycolysis and pyruvate oxidation), protein content, and developmental competence of caprine oocytes and cumulus-oocyte complexes (COCs). Abattoir-derived COCs were matured for 18-20 hr in a defined, SOF-based medium containing 0.75, 1.5 (follicular fluid = 1.4 mM), or 3.0 mM glucose, and 3.0, 6.0 (follicular fluid = 7.1 mM), or 12.0 mM L-lactate. The protein content of oocytes and COCs was not affected (P > 0.05) by the concentration of glucose and lactate in the maturation medium. Increasing glucose and lactate decreased (P < or = 0.05) glycolytic activity of oocytes, without affecting (P > 0.05) pyruvate oxidation. In COCs, increasing glucose concentrations tended (P = 0.07) to decrease glycolysis. When metabolic activity was corrected for protein content (pmol/microg protein/3 hr), increasing glucose or lactate concentrations in the medium decreased (P < or = 0.05) pyruvate oxidation in oocytes, but increased (P < or = 0.05) pyruvate oxidation in COCs. Embryonic development (cleavage and blastocyst development, hatching, and cell number) was not affected (P > 0.05) by the glucose and lactate concentrations tested. These results indicate that concentrations of glucose and lactate in the medium have cell type-specific effects on metabolism of oocytes and COCs, but do not affect developmental competence within the range of concentrations tested.

Animals↗

PubMed2004

Gene transfer into intact fetal skeletal muscle grown in vitro.

The development of an organ culture system for growing prenatal intercostal muscle in vitro and its use to study gene function is described. Fetal skeletal muscle is relatively inaccessible during the key stages of its development, and this method enables DNA transfections and other manipulations to be carried out. The system allows cell proliferation and differentiation to continue and also maintains the morphology and fiber types of developing muscle. Gene transfer into cultured embryonic intercostal muscle was achieved by square-pulse electroporation of intact pieces of tissue. Expression of a marker gene (GFP) was found within 5 h and maintained for 2 days in muscle fibers and cells. The technique should enable the function of genes implicated in muscle development and disease to be studied at stages when access is difficult and in a controlled environment.

Animals↗

PubMed2005

Cathlink 20: a subcutaneous implanted central venous access device used in children with sickle cell disease on long-term erythrocytapheresis--a report of low complication rates.

BACKGROUND: Experience with the use of central venous access device (CVAD) in children with sickle cell disease (SCD) on hypertransfusion is limited and published studies report wide variability in the rates of CVAD-associated complications. PROCEDURE: In this study, a total of 18 Cathlink 20 ports (Bard Access systems, Salt Lake City, UT) were implanted in 15 patients aged 7-20 years with SCD for 19, 230 catheter patient days. RESULTS: No peri-operative complications were observed. Three episodes of catheter occlusion requiring replacement occurred in two patients for an observed rate of 0.16 per 1,000 catheter patient days for thrombotic occlusion. One patient required port replacement and another patient required replacement twice. In 13 out of 15 patients, the median duration of port use was 45 months. No episode of catheter-associated bacteremia or catheter tunnel infections was observed. CONCLUSIONS: Comparing our results with other reported studies of CVAD-associated complications in patients with SCD, we observed a lower rate of complications with the use of Cathlink 20 ports. These findings may be partly related to the design of the port and partly to a dedicated group of nurses accessing the ports in a controlled environment in an apheresis unit.

Adolescent↗