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Results for “Environment, Controlled”

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PubMed1981

Spatial sampling by dendritic trees in visual cortex.

Kittens were reared in vertically or horizontally striped cylinders. After rearing exposures of 400-500 h, responses of single neurons were determined as a function of orientation of a square wave grating stimulus. These data suggest that the rearing environment did alter orientation preference in some of the kittens. The visual cortices of the stripe-reared kittens and of control kittens were impregnated according to a Golgi-Cox method. Dendrites of layer IV stellate cells were tracked and analyzed in three dimensions by a computer-microscope. Four methods of analyzing the spatial distribution of dendrites are described and discussed. Two methods previously described in the literature were not sufficiently sensitive to detect any differences among kittens exposed to vertical or horizontal stripes or to a control environment. Two newly developed methods were able to provide initial evidence for rearing effects on dendritic trees in visual cortex. The more detailed of these new methods describes the angular location of dendritic segments, with respect to standard brain axes, as a function of distance from the cell body. Data obtained by means of this method of dendritic angular distribution (DAD) plots suggests a number of conclusions. Rearing animals in a striped environment may influence the way in which dendrites of layer IV stellate cells of visual cortex distribute themselves in the neuropil. The effect of selective rearing on dendritic distribution does not appear to extend back to those portions of the dendritic tree closest to the cell body. This influence of rearing in a selective environment may be explained by hypothesizing that during development dendrites distribute themselves in ways that tend to maximize the effects of spatiotemporal summation for the postsynaptic neurons.

Animals↗

PubMed2005

Influence of controlled lactic fermentation on growth and sporulation of Bacillus cereus in milk.

The growth and sporulation of Bacillus cereus NVH 45 in a fermentor with controlled pH or simulated pH conditions were investigated. The study was carried out in a fermentor to measure the influence of a rapid and a slow lactic acid production on the inhibition of B. cereus in a controlled environment during the initial part of fermentation and to observe if other factors than lactic acid influenced the inhibition. In the controlled pH experiments the pH was allowed to decrease to an end pH 5.0, 5.5 or 6.0 either by Lactobacillus casei 2756 (a fast acid producer) or Lactobacillus acidophilus NCFB 1748 (a slow acid producer). In co-cultures of Lb. casei 2756 and B. cereus NVH 45, low numbers (10-70 cfu/ml) of B. cereus NVH 45 were observed at end pH 5.5 (72 h) while at pH 5.0 no viable cells (<10 cfu/ml) were detected (48-72 h). B. cereus NVH 45 did not sporulate in co-culture with Lb. casei 2756. In co-culture with Lb. acidophilus NCFB 1748, B. cereus NVH 45 sporulated and survived as spores. In these co-cultures B. cereus NVH 45 grew to higher maximum counts (>10(7) cfu/ml) than with Lb. casei 2756 (<10(7) cfu/ml). Significantly different amounts of lactic acid were observed between the two co-cultures after 7 and 12 h. A rapid decrease of pH appears to prevent B. cereus from sporulating and it seems that it is enough to just reach pH 5.0 rapidly and keep that pH to achieve the desirable inhibition of B. cereus. In the simulated pH experiments B. cereus NVH 45 was inoculated in the fermentor and the different pH developments from different LAB strains were monitored by addition of lactic acid. These experiments showed the same tendency: a fast pH reduction during the initial hours of fermentation, simulating lactococci, resulted in complete inhibition of B. cereus NVH 45 (<10 cfu/ml). However, when simulating the pH development of the two different Lactobacillus strains, complete inhibition of B. cereus NVH 45 was not seen. In co-cultures competition for nutrients with consequences for cell density appears to be important. Based on these results it seems that B. cereus must reach a certain density to induce sporulation.

Animals↗

PubMed1966

Fatty Acid accumulation in maturing flaxseeds as influenced by environment.

The effects of temperature and light on boll and shoot maturity and on the accumulation of fatty acids in developing seeds of flax (Linum usitatissimum L.) were determined in controlled environments. Palmitic and linoleic acids decreased but linolenic increased in percent as seed formation progressed. In the same period, oleic acid increased in percent in 1 variety and decreased in another. Increased temperatures hastened these changes and resulted in decreased iodine value of the oil at maturity.Calculated on a weight basis (mg per 1000 seeds), all 5 major fatty acids increased during seed formation. Increased temperatures initially accelerated the accumulation of all fatty acids, but the period of net fatty acid synthesis was eventually shortened in comparison with cooler temperatures. At 15 degrees and 20 degrees , linolenic acid accumulation closely paralleled the rate of boll maturation, measured by boll moisture content; at 30 degrees linolenic accumulation ceased before maturation could be detected.A photoperiod of 20 hours accelerated plant maturity resulting in decreased seed weight in comparison with a photoperiod of 16 hours. Eight hour photoperiod favored late blossoming and depressed seed weight, oil content, and fatty acid content. Weights of linoleic and linolenic acids were high in both the 16 and 20 hour photoperiods.Linolenic acid was reduced in percent and weight per 1000 seeds at light intensities of 1200 ft-c as compared with 2700 ft-c.

Journal Article↗

PubMedDate not supplied

Can correct closed-chest compressions be performed during prehospital transport?

INTRODUCTION: The resuscitation rate from out-of-hospital cardiac arrest is low. There are many factors to be considered as contributing to this phenomenon. One factor not previously considered is the impact of a moving ambulance environment on the ability to perform closed-chest compressions. HYPOTHESIS: Proper closed-chest compressions can be performed in a moving ambulance. METHODS: A cardiopulmonary resuscitation (CPR) training mannequin with an attached skill meter (Skillmeter ResusciAnnie, Laerdal, Armonk, N.Y., USA) that measures each chest compression for proper depth and hand placement was used. Ten emergency medical technician-basic (EMT-B) certified prehospital providers were assigned into one of five teams. Each team performed a total of four sessions of five minutes of continuous closed-chest compressions on the mannequin. Two sessions were done by each team: one in the control environment with the mannequin placed on the floor, and the other in the experimental environment with the mannequin placed in the back of a moving ambulance. The ambulance was operated without warning lights and siren, and all traffic rules were obeyed. The percentage of correct closed-chest compressions was recorded for each session, and the mean values were compared using Student's t-test with alpha set at 0.01 for statistical significance. RESULTS: Ten sessions of compressions were done in both environments. The mean percentage of correct compressions was 77.6 +/- 15.6 for the control group and 45.6 +/- 18.3 for the ambulance group (p = 0.0005). CONCLUSION: A moving ambulance environment appears to impair the ability to perform closed-chest compressions.

Ambulances↗

PubMed1987

Relationships between dietary protein, dietary energy, rearing environment, and nutrient utilization by broiler breeder pullets.

The relationship between dietary energy and protein and their interaction with method of restriction and environment were studied. In Experiment 1, two isocaloric diets (2750 kcal/kg) formulated to contain either 13.5% or 15.5% protein were fed to broiler breeder pullets from hatching through 21 weeks of age. There were no significant differences in body weight due to dietary protein but chicks fed the 13.5% protein ration did require a significantly greater quantity of feed to produce an equivalent body weight. Sexual maturity, peak egg production, and egg size were not affected by the level of dietary protein but total egg production was significantly decreased in pullets fed the 13.5% protein diet. In Experiment 2, 2970 kcal/kg ration containing 15.5% protein was fed to pullets that were reared under two different lighting environments, natural daylength or 24 hr light for the first 7 days and 8 hr light per day thereafter. Pullets housed in the controlled environment and reared on an every-other-day restriction program had significantly improved feed utilization compared with similarly restricted birds kept under natural light. Environmental effects on feed utilization were not as great in the every day restriction treatment. Chicks exposed to natural daylight and fed 15.5% protein diets had similar caloric efficiencies (kcal/g) at 15 weeks of age in both experiments despite dietary density differences of 220 kcal/kg. This supports a hypothesis that above some minimal level of protein intake, caloric intake has the greatest control over body weight gain in restricted pullets, particularly where every-other-day feeding is used during part of the growing period.

Animal Feed↗

PubMed2003

Improving accuracy in simulated pharmacy assembly tasks using workspace interventions to enhance the cognitive environment.

In this study, the error-reducing effectiveness of two work-environment interventions was examined in a simulated pharmacy task. 110 participants worked for 3 to 4 hours filling approximately 110 orders for simulated drugs in a laboratory-based, controlled environment. One group of participants used a monitor-mounted copy strip to enhance data entry, and another group used the copy strips as well as labeled product sleeves on stock bottles to enhance product selection. Results indicated that participants who worked using copy strips as well as participants who worked using both copy strips and product sleeves were more accurate in their order-filling performance than participants in the control condition. However, participants in the copy strip and the copy strip/sleeve conditions did not differ from one another in accuracy. Further research ideas and potential explanations of these data are discussed.

Achievement↗

PubMed1994

Complementary chromatic adaptation: photoperception to gene regulation.

Many photosynthetic organisms can acclimate to the quantity and quality of light present in their environment. In certain cyanobacteria the wavelengths of light in the environment control the synthesis of specific polypeptides of the light harvesting antenna complex or phycobilisome. This phenomenon, called complementary chromatic adaptation, is most dramatically observed in a comparison of cyanobacteria after growth in green light and red light. In red light-grown cells the phycobilisome is largely composed of phycocyanin and its associated linker polypeptides (the latter are important for the assembly of the phycocyanin subunits and their placement within the light harvesting structure); the organisms appear blue-green in color. In green light-grown cells the phycobilisome is largely composed of phycoerythrin and its associated linker polypeptides; the organisms appear red in color. The ways in which these cyanobacteria sense their changing light environment and the regulatory elements involved in controlling the process of complementary chromatic adaptation are discussed in this review.

Adaptation, Physiological↗

PubMed2002

Rapid regulation of light harvesting and plant fitness in the field.

We used Arabidopsis thaliana mutants to examine how a photosynthetic regulatory process, the qE-type or DeltapH-dependent nonphotochemical quenching, hereafter named feedback de-excitation, influences plant fitness in different light environments. We show that the feedback de-excitation is important for plant fitness in the field and in fluctuating light in a controlled environment but that it does not affect plant performance under constant light conditions. Our findings demonstrate that the feedback de-excitation confers a strong fitness advantage under field conditions and suggest that this advantage is due to the increase in plant tolerance to variation in light intensity rather than tolerance to high-intensity light itself.

Adaptation, Physiological↗

PubMed1992

Critical role of bicarbonate in calcium release from bone.

Calcium release from cultured bone is pH dependent; net calcium flux (JCa) from bone increases with decreasing pH. At a similar decrement in pH there is greater JCa when acidosis is produced by a low medium bicarbonate concentration ([HCO3-]), a model of metabolic acidosis (Met), compared with an increased medium PCO2, a model of respiratory acidosis (Resp). To separate the role of [HCO3-] from that of pH in inducing JCa we cultured calvariae for 3 h under three different neutral (pH approximately 7.4) isohydric environments [control (Ctl), fully compensated Met (C-Met), or fully compensated Resp (C-Resp)] and two different acid (pH approximately 7.1) isohydric environments (Met or Resp). During neutral pH (Ctl, C-Met, and C-Resp) there was JCa from bone during C-Met (decreased [HCO3-]), no net flux during Ctl (normal [HCO3-]), and JCa into bone during C-Resp (increased [HCO3-]); and JCa was correlated inversely with [HCO3-] (r = -0.824, n = 36, P less than 0.001). During acid pH there was greater JCa from bone during Met (decreased [HCO3-]) than during Resp (normal [HCO3-]); and JCa was again correlated inversely with [HCO3-] (r = -0.848, n = 22, P less than 0.001). JCa from bone during Met and Resp was greater than C-Met and C-Resp, respectively. The addition of the osteoclastic inhibitor salmon calcitonin did not alter the relative JCa results. Thus at a constant pH the magnitude of JCa from cultured neonatal mouse calvariae appears dependent on the [HCO3-]; the lower the [HCO3-], the greater the calcium efflux.(ABSTRACT TRUNCATED AT 250 WORDS)

Acidosis↗

PubMed1988

What is the role of reinforcement in early language acquisition?

Monolingual American and Mexican 2- and 3-year-old children were exposed to a foreign language in a naturalistic but controlled environment. Children were randomly assigned to 2 groups. 1 group was differentially reinforced throughout the study for the use of foreign vocabulary. The control group was first reinforced nondifferentially for use of the native language or the foreign language and later was switched to differential reinforcement for the foreign language. Frequencies of spontaneous foreign word production and other verbal responses were computed, and formal assessments of comprehension and production of the foreign words were conducted. Differential reinforcement resulted in accelerating frequencies of spontaneous foreign language use and better performance on both comprehension and production tests. Under nondifferential reinforcement, rates of spontaneous foreign language use were low and static. Results are interpreted as evidence that the acquisition of expressive vocabulary is a function of socially mediated reinforcement.

Child, Preschool↗

PubMed1993

An expert system for culture-based infection control surveillance.

Hospital-acquired infections represent a significant cause of prolonged inpatient days and additional hospital charges. We describe an expert system, called GERMWATCHER, which applies the Centers for Disease Control's National Nosocomial Infection Surveillance culture-based criteria for detecting nosocomial infections. GERMWATCHER has been deployed at Barnes Hospital, a large tertiary-care teaching hospital, since February 1993. We describe the Barnes Hospital infection control environment, the expert system design, and a predeployment performance evaluation. We then compare our system to other efforts in computer-based infection control.

Cells, Cultured↗

PubMed1995

Persistence of distal motor control in the locked in syndrome. Review of 11 patients.

We report 11 patients with the locked in syndrome (LIS). The functional outcome was good in four patients with notable motor recovery, but motor deficit remained seriously disturbed in seven patients. All of the patients regained some distal control of finger and toe movements, often allowing functional use of a digital switch. The independence thereby gained is worthwhile, in some patients allowing environment control, communication by means of a computer, and electric wheelchair ambulation. When motor recovery occurs, the progression is disto-proximal with dramatic axial hypotonia. In five patients clinical insomnia was noted and polysomnography showed a reduction of REM sleep. The implications of systems other than the pyramidal tracts in the physiopathology of LIS are discussed.

Adolescent↗

PubMed2004

Studies of human intervertebral disc cell function in a constrained in vitro tissue culture system.

STUDY DESIGN: This is a laboratory-based study examining a novel in vitro culture system for intervertebral disc tissue. OBJECTIVES: Address the hypothesis that "the novel culture system will preserve intervertebral disc tissue matrix and cell function and prevent cellular apoptosis for periods up to 21 days." SUMMARY OF BACKGROUND DATA: Studies of cell function in human intervertebral disc tissue are scarce. In vivo study of human intervertebral disc cells remains impracticable; in situ molecular biology in histologic sections lacks a dynamic dimension; and as for in vitro studies, cell culture often lacks physiologic relevance and explant cultures are subject to loss of tissue integrity and altered cell behavior. There is a biologic and therapeutic need for a satisfactory explant culture system for studying human intervertebral disc tissue in a controlled environment. METHODS: Samples of human intervertebral disc tissue, obtained at surgery, were examined for a number of tissue and cell parameters immediately after excision (controls) and following culture of tissue samples either in a plastic ring or unconstrained in tissue culture medium for up to 3 weeks. Data were compared between cultured tissue and controls. RESULTS: By comparison with control tissue, unconstrained explants swelled, tissue structure was disturbed, and there were profound changes in cell function. By contrast, tissue cultured in plastic rings maintained tissue structure, and after 3 weeks, the cellular parameters were the same as in controls. CONCLUSIONS: This is the first reported system to preserve cell function of human discal explants for long periods in tissue culture. It will be a useful tool for a wide range of investigations of intervertebral disc biology that have not hitherto been possible.

Adult↗

PubMed1979

Evaluation of ammonia stress and coccidiosis on broiler performance.

Eighty broiler chickens were randomly assigned to each of 12 chambers in a controlled environment poultry facility. Ammonia gas was injected at 0, 50, or 100 ppm from 28 to 53 days of age. All chicks, except the control pens, were innoculated with coccidia at 36 days of age. No significant differences were found in mortality, but weight gains were significantly reduced in chambers that received ammonia gas. This was probably due to the increase in severity of air sac and intestinal lesions in the ammonia pens.

Air Sacs↗

PubMed2005

The digital pen and paper. Evaluation and acceptance of a new data acquisition device in clinical settings.

OBJECTIVES: To evaluate the efficiency and acceptance of digital pen and paper technology for real-time clinical data acquisition. METHODS: A prospective interventional unblinded study involving consecutive patients in two clinical settings during a defined time-frame was proposed. The first trial was designed as a stress test to evaluate acceptance in a workload-intensive environment. Acceptance was assessed using observations and a satisfaction questionnaire. The second trial was intended to determine the reliability of data acquisition in a controlled environment. Reliability was assessed by comparing the performance of the digital pen against scanner analysis and a double human blinded acquisition. RESULTS: Overall, users were satisfied with the use of the digital pen (median 3 on a Likert-scale (-5, 5)). Without any specific user training, successful data acquisition was greater than 80%. Use of this technology required less adaptation than standard computer devices, and was easy to learn and use. Ergonomic problems shaded the perception of the technology by inducing an increased cognitive load. Digitalized data was missing either because of a bug or due to lack of data validation. The reliability obtained with the digital pen was significantly lower to that obtained with the scanner. CONCLUSIONS: Natural technology such as the digital pen proved to be a good tool in stressful clinical environments without interfering with the normal workload or increasing the time for data acquisition. However, in order to improve quality of data acquisition, designing acquisition forms specifically for the use of digital pens is of paramount importance.

Anesthesia, Obstetrical↗

PubMed1991

Bionic organs.

When a lizard loses its tail, a new caudal appendage soon grows to replace the one that is missing. But when a human loses a kidney, severs a peripheral nerve or worse, the spinal cord, that organ is lost forever. Such at least is conventional thinking. But imagine that the victim of an industrial accident with a paralyzed hand could achieve new levels of function by inducing axonal regrowth through a synthetic nerve guidance channel; or that a Parkinsonian patient's symptoms could be relieved by implanting in his brain neural tissue encased in a selectively permeable polymer envelope; or that the inexorable progression of the vascular complications of juvenile diabetes could be stopped, even reversed, by a membrane-protected xenograft of insulin-producing tissue. This is the dream of bionic organ science. It is predicated on two lines of technological achievement: the availability of ultra-thin, biocompatible, selectively permeable polymer membranes which can protect a transplant against immune rejection while allowing solute exchange between the graft and its environment; and the synthesis of novel materials, some biostable, some bioresorbable, which can serve as scaffolding or anchor for tissue regrowth in the geometrically and chemically controlled environment of an implant. The fabrication, growth and survival of composites of living tissues with synthetic polymers, often enhanced by the incorporation of specific cell growth factors or inhibitors, has been demonstrated at the tissue culture level, and extended in vivo to experimental models of human endocrine deficiency or neurological defects. The key to progress with bioartificial organs is the confluence of knowledge ranging from materials science to cell and molecular biology to experimental surgery. Obstacles to clinical implementation of this new therapeutic concept include: large scale procurement of specific tissue structures or isolated postmitotic cells from animal sources; demonstration of safety and efficacy of spontaneously occurring, bioactive tumor cell lines; verification of long-term stability and bio-acceptance of polymer implants; and industrialization of the fabrication process to meet quality control, shelf-life and commercial distribution requirements.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗

PubMedDate not supplied

Fourier transform infrared imaging for high-throughput analysis of pharmaceutical formulations.

Fourier transform infrared (FTIR) spectroscopic imaging with infrared array detectors has recently emerged as a powerful materials characterization tool. We report a novel application of FTIR imaging for high-throughput analysis of materials under controlled environment. This approach combines the use of spectroscopic imaging with an attenuated total reflection (ATR)-IR cell, microdroplet sample deposition system, and a device that controls humidity inside the cell. By this approach, it was possible to obtain "chemical snapshots" from a spatially defined array of many different polymer/drug formulations (more than 100) under identical conditions. This method provides direct measurement of materials properties for high-throughput formulation design and optimization. Simultaneous response (water sorption, crystallization, etc.) of the array of formulations to the environmental parameters was studied. Implications of the presented approach range from studies of smart polymeric materials and sensors to screening of pharmaceuticals and biomaterials.

Calibration↗

PubMed2004

Appropriate methods to assess the effectiveness and efficacy of treatments or interventions to control cancer pain.

Pain is common in cancer patients. To ensure optimal pain management efficacy and effectiveness of new drugs and treatments have to be investigated in clinical trials. Efficacy trials such as randomised controlled trials (RCT) are experimental studies and estimate the maximum potential benefit to be derived from an intervention in ideal circumstances and under a controlled environment. RCTs are the only trial design to establish causal effects. A crossover study is a special type of RCT where patients serve as own controls. In efficacy studies the intervention and the control group should be as homogeneous as possible, confounding variables are controlled, bias is reduced, internal validity is high whereas external validity is low. Studies looking at effectiveness assess clinical practice and reflect real life circumstances. They rely high on external validity at the expense of careful controls, the study population is heterogeneous, confounding variables are examined. Cohort studies follow a group or groups of individuals with a common characteristic over a period of time to measure outcomes. Case-control studies start with the outcome and compare the characteristics of two groups of interest, those with the outcome and those without to identify factors which occur more or less often in the poor outcome group. Definition of outcome criteria is crucial both for efficacy and effectiveness studies and is often a primary problem. All clinical studies must use valid and reliable outcome measures.

Cross-Over Studies↗