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At least 91 records · Page 5Linked to original sources
PubMed2005

Effect of temperature, elevated carbon dioxide, and drought during seed development on the isoflavone content of dwarf soybean [Glycine max (L.) Merrill] grown in controlled environments.

The effects of elevated temperature, carbon dioxide, and water stress on the isoflavone content of seed from a dwarf soybean line [Glycine max (L.) Merrill] were determined, using controlled environment chambers. Increasing the temperature from 18 degrees C during seed development to 23 degrees C decreased total isoflavone content by about 65%. A further 5 degrees C increase to 28 degrees C decreased the total isoflavone content by about 90%. Combining treatments at elevated temperature with elevated CO(2) (700 ppm) and water stress to determine the possible consequences of global climate change on soybean seed isoflavone content indicated that elevated CO(2) at elevated temperatures could partially reverse the effects of temperature on soybean seed isoflavone content. The addition of drought stress to plants grown at 23 degrees C and elevated CO(2) returned the total isoflavone levels to the control values obtained at 18 degrees C and 400 ppm CO(2). The promotive effects of drought and elevated CO(2) at 23 degrees C on the 6' '-O-malonygenistin and genistin levels were additive. The individual isoflavones often had different responses to the various growth conditions during seed maturation, modifying the proportions of the principal isoflavones. Therefore, subtle changes in certain environmental factors may change the isoflavone content of commercially grown soybean, altering the nutritional values of soy products.

Carbon Dioxide↗
PubMed2003

"Bark parks"--a study on interdog aggression in a limited-control environment.

As limited-control dog parks become more popular, concerns arise about whether these parks encourage interdog aggression. Systematic observations made at 1 park over 72 hr across 8 months found that 28 conflicts or potential conflicts occurred (< 0.5%). Of these, 14 were clear aggressive episodes. Each lasted less than 1 min (< 0.33% of total observation time). There were 14 other incidents of possible aggression that were ambiguous in nature. Each lasted less than 30 sec (< 0.17%). None of these incidents led to serious injury. Of the 177 dogs observed, only 9 were aggressive toward other dogs (5%): 6 aggressors, once each; 2 aggressors, twice each; 1 aggressor, 3 times. Results indicate that aggression in limited-control dog parks may be relatively rare and probably presents only a limited risk to dogs and their caregivers (owners). In part, this may be because owners who frequent dog parks are self-selecting, self-monitoring, and self-limiting in regard to dog aggression.

Aggression↗
PubMed1990

A small-scale controlled environment chamber for the investigation of the effects of pollutant gases on plants growing at cool or sub-zero temperature.

A new, small-scale controlled environment plant growth chamber is described, which permits accurately controlled temperatures from ambient (c. 20 degrees C) down to -5 degrees C in the day or -15 degrees C at night. The system also allows controlled injection of pollutant gases. The chamber is based on a modified commercial chest freezer with temperature control achieved through by-passing the cooling coils in the inner walls of the freezer. This by-pass is controlled by a BBC microcomputer which gives nominal temperature control to 0.1 degrees C over definable diurnal temperature profiles. Photoperiod is also controlled by the microcomputer. The chamber forms a virtually closed system to which pollutant gases are added by injection from low concentration cylinders, regulated using mass flow controllers. The accuracy with which pollutant concentrations are controlled is increased by filtration of the air-stream after passing over the experimental plants: i.e. a 'single-pass' system is adopted. In operation air temperatures across the chambers are controlled to within 1-1.5 degrees C of the pre-set value over the range 25 to -10 degrees C. Leaf temperatures are 2.5-3.0 degrees C above air temperatures during the day, with a total energy input of c. 180 Wm(-2) from two 400 W metal halide lamps. The lamps provide a photon fluence rate of 270+/-30 micromol quanta PAR m(-2) s(-1) at plant height. During the dark, leaf temperatures deviate less than 1.0 degrees C from air temperature. Soil temperatures are controlled separately from air temperature and are held above zero at all times. To date, fumigation, with NO(2) and SO(2) has been confined to the daytime. At pre-set concentrations of 20 nl litre(-1) variations during fumigation were less than 2.0-2.5 nl litre(-1) and 0.5 nl litre(-1), respectively.

Journal Article↗
PubMed2000

New controlled environment vitrification system for cryo-transmission electron microscopy: design and application to surfactant solutions.

A newly designed controlled environment vitrification system for cryo-transmission electron microscopy of vitrified samples (cryo TEM) is presented. It significantly reduces the lag-time from blotting to vitrification by means of an optimized blotting procedure. Furthermore, a modified transfer system allows rapid transfer of the vitrified sample into the microscope and reduces the equilibration time. The practicable throughput of samples is thereby markedly increased. This new equipment is used to determine the overall size of individual polymer-like mixed lecithin-bile salt micelles, which very critically depends on the composition of the sample. The quantitative agreement with the results from independent light scattering experiments on the same sample supports the validity and performance of the presented sample preparation and handling procedures. In addition, these experiments demonstrate that cryo TEM experiments not only provide direct structural information, but furthermore permit a quantitative determination of micellar properties.

Bile Acids and Salts↗
PubMed1976

Controlled environment culture of bone marrow explants from human myeloma.

Bone marrow biopsy specimens from patients with myeloma were cultured in either 1 of 2 thin-film culture systems, a controlled environment steady state system or a rocker tube configuration of the system, for periods up to 42 days. Both functional and morphological characteristics of the myeloma cells were well-maintained in these systems. Cytocentrifuge preparations of the culture media disclosed hematopoietic cells that included from 5% to almost 100% plasma cells. Histological examination of the cultured specimens disclosed infiltration of the marrow with myeloma cells. Myeloma proteins were released at a steady rate throughout the period of culture after the 1st 4 days. Bone-resorbing activity was demonstrated in the culture media in 7 of 9 myeloma culture media and was well maintained, particularly during the 1st week of culture. This activity was associated with severe osteolytic lesions in the donor patient and marked infiltration of the cultured specimen by myeloma cells. The potential use of these organ culture systems for the further definitive identification of the factor responsible for bone destruction in myeloma is discussed.

Bone Marrow↗
PubMed1992

Controlling allergies by controlling environment. A big help for your patients.

Control of the environment is a cost-effective method of limiting allergic reactions in susceptible people. For physicians working with allergic patients, this approach involves guiding the patient and family in ridding their home and surroundings of allergens and irritants. Dr. Klein discusses the environmental-control protocol, particularly in regard to dust mites, mold, pollen, and pets.

Air Conditioning↗
PubMed1986

Influence of body weight and number of inseminations on fertility of progestogen-treated ewe lambs raised in controlled environments.

The influence of body weight at breeding on reproductive response to one and two artificial inseminations (AI) of fresh extended semen was assessed in 195 crossbred ewe lambs selected for early breeding and compared with 159 adult ewes, all housed indoors in a controlled environment. In six trials, ewe lambs and adult ewes in progestogen-induced estrus were inseminated 55 to 57 h after sponge removal. One-half of the lambs and one-fourth of the adults received a second insemination at 60 h. Resultant reproductive performance of both groups indicated no advantage in a double insemination. Overall fertility, litter size and fecundity after one and two inseminations were 33%, 1.7 and .6 for ewe lambs and 68%, 2.4 and 1.6 for adult ewes, respectively. Embryonic mortality after the first 2 wk of pregnancy was estimated at 24% for ewe lambs and 9% for adults. The influence of body weight was analyzed by grouping the ewe lambs according to body weight at breeding. The lambs in group 1 weighed 30 to 35 kg; group 2, 36 to 40 kg; group 3, 41 to 45 kg and group 4, 46 to 50 kg. The proportion of ewes lambing in groups 1, 2, 3 and 4 was 16, 34, 39 and 48%, respectively. Corresponding litter sizes were 1.4, 1.6, 1.8 and 2.0. Fecundity increased (P less than 01) from .2 in group 1 to 1.0 in group 4. The results indicate that even when ewe lambs are bred by AI (eliminating a ram behavioral problem), sheep with heavier body weights produce more lambs per ewe bred.

Animals↗
PubMed1992

Health visiting: action research in a controlled environment.

The nature of health visiting is discussed. It operates in a radically different way from any of the curative services. Research into the effectiveness of health visiting must therefore take into account the many differences in context, in professional goals and in the nature of the interaction between health visitors and their "clients", compared with the work of the curative professions within their more controlled and controlling environments. The evaluation of one large scale health visitor intervention study is used here to highlight these differences. Health visiting research needs to free itself from the attempts by some to apply the laboratory model of evaluation, if it is to develop a corpus of "action research" thinking which reflects its more human and developmental characteristics.

Child↗
PubMed1994

Comparison of Dehydrin Gene Expression and Freezing Tolerance in Bromus inermis and Secale cereale Grown in Controlled Environments, Hydroponics, and the Field.

There have been very few reports on the expression of stress-responsive genes in field-grown material. A barley dehydrin cDNA was used to investigate the expression of dehydrin-like transcripts after low-temperature and abscisic acid-induced acclimation of bromegrass (Bromus inermis Leyss) suspension cells and of bromegrass and rye (Secale cereale) plants grown in the field and under controlled environmental conditions. Field-acclimated plants accumulated high levels of dehydrin transcripts and were very freezing tolerant. Plants grown in pots and hydroponics under controlled environments also accumulated dehydrin transcripts and showed increased freezing tolerance. Simulation of a combined drought and freezing stress in pots resulted in expression of dehydrin-like transcripts comparable to those observed in field-acclimated material.

Journal Article↗
PubMed2005

Propylene glycol vapor contamination in controlled environment growth chambers: toxicity to corn and soybean plants.

A major, often unrecognized variable regulating plant growth in semi-closed environment is air contaminant. The vapor of propylene glycol (PG), which was used as coolant in growth chambers, has been found to be toxic to corn (Zea mays L.) and soybean (Glycine max L.) plants. PG solution leaked from a valve packing system and volatilized to vapor, which was trapped in a semi-closed growth chamber. Symptoms of leaf edge chlorosis, later developing into necrosis, were observed on the third day of emergence or on the third day after moving healthy plants into the chamber. For young soybean plants, symptoms were slightly different from those observed in corn plants; the chlorosis symptoms were not uniformly distributed on all leaves. Some soybean leaves curled up and others had white spots. This problem was identified by using a portable photoionization detector to obtain instantaneous readings of total volatile organic compound concentrations inside the chambers. The presence of PG in selected chambers was verified using sample collection with solid phase microextraction (SPME) followed by analysis with multi-dimensional gas chromatography mass spectrometry (MD-GC-MS). This information is pertinent to researchers who use controlled environment to grow plants.

Air Pollutants↗
PubMed2000

[Effects of CO2 concentration on growth and development of lettuce in controlled environment].

Objective. To study the tolerance of lettuce to elevated CO2 concentration in Controlled Ecological Life Support System (CELSS). Method. Lettuce was cultivated in the Ground-based Experimental Facility for Higher Plant Cultivation in Space (GEFHPCS), in which many parameters were kept unchanged, while concentration of CO2 was controlled at 5 different levels (2000-10000 micromoles mol-1). During the growing periods, the morphologies of lettuce were observed every day, the replenished amounts of CO2 to GEFHPCS and water to the nutrient fluid box as well as the amounts of condensed water collected from GEFHPCS were all recorded every day. After harvest, the output and photosynthetic rate were calculated and lots of constituents of lettuce were analyzed. Result. The growth of lettuce were relatively ideal when CO2 concentration was at 6000 micromoles mol-1, but an obviously withering appearance was found when CO2 concentration increased 10000 micromoles mol-1, this time the output and quality of lettuce were unsatisfactory. Conclusion. It would be optimal when CO2 concentration is controlled at about 6000 micromoles mol-1 in a lettuce-cultivating chamber.

Biomass↗
PubMed1975

Conversations with a chimpanzee in a computer-controlled environment.

The linguistic-type skills of a young chimpanzee (Pan) acquired in a computer-controlled language-training situation are reviewed. Those skills include facile acquisition of vocabulary, object naming, color naming, appropriate use of "yes" and "no" in response to certain questions, and conversation. In conversations the subject has formulated novel sentences and without special training has asked that objects be named, whereupon requests were made that they be given to her. These findings are interpreted in terms of how enriched environments can serve to bring forth novel communication skills in the chimpanzee, which is otherwise alinguistic; how the challenge of the environment can serve to limit manifest intelligence; and how a cognitive, rather than the traditional stimulus-response, framework is required for understanding the communication skills and psychological processes of the chimpanzee.

Animals↗
PubMed2005

Investigating cigarette-smoke indoor pollution in a controlled environment.

The objective of this study was to investigate the evolution of pollutant concentrations generated by smoking in a controlled indoor environment. For this purpose, a small flat in the centre of Athens, Greece was equipped with NO(x), O(3) and SO(2) continuous measuring instruments and portable analysers for spot measurements of TVOCs and CO(2), while two volunteer smokers remained inside and smoked as normal inhabitants. The results indicated that when windows are kept closed and smoking takes place NO(x), CO(2) and TVOCs concentrations increase by an order of 3, 4 or 10 times, respectively, and decrease returning to initial levels after 1 or 2 h.

Air Pollution, Indoor↗
PubMed1980

Air movement and heat loss from sheep. III. Components of insulation in a controlled environment.

The rate of sensible heat loss from a Clun Forest ewe was studied at several fleece depths in a temperature-controlled chamber. A simple resistance analogue was used to describe the heat flow from different body regions. Heat loss from the trunk depends largely on the mean fleece depth l. The fleece resistance was about 1.5 s cm-1 per centimetre depth. Heat transfer through the fleece was accounted for by molecular conduction, thermal radiation and free convection. The fleece conductivity -kb attributed to free convection depends on the mean temperature difference (-Tst---Tct) across the fleece according to the relation -kb = 8.0 (-Tst---Tct)0.53. Estimates of the sensible heat flux from the trunk at environmental temperatures, Ta, between 0 and 30 degrees C range from about 8 W (l = 7.0 cm, Ta = 30 degrees C) to about 160 W (l = 0.1 cm, Ta = 0 degrees C). In contrast, the sensible heat loss from the legs depends mainly on the local tissue resistance. For environmental temperatures between 0 and 30 degrees C, the calculated tissue resistance for this region of the body varied from about 8 to 1 s cm-1. The corresponding heat loss from the legs was between 10 and 20 W, compared with between 3 and 7 W from the head. The fastest heat loss from the legs occurred at an environmental temperature of about 12 degrees C. Although the proportion of the heat loss from the extremities depends on environmental temperature, the total heat loss (sensible or latent) was closely related to the mean skin temperature of the trunk.

Air Movements↗
PubMed1996

A system and methodology for measuring volatile organic compounds produced by hydroponic lettuce in a controlled environment.

A system and methodology were developed for the nondestructive qualitative and quantitative analysis of volatile emissions from hydroponically grown 'Waldmann's Green' leaf lettuce (Lactuca sativa L.). Photosynthetic photon flux (PPF), photoperiod, and temperature were automatically controlled and monitored in a growth chamber modified for the collection of plant volatiles. The lipoxygenase pathway products (Z)-3-hexenal, (Z)-3-hexenol, and (Z)-3-hexenyl acetate were emitted by lettuce plants after the transition from the light period to the dark period. The volatile collection system developed in this study enabled measurements of volatiles emitted by intact plants, from planting to harvest, under controlled environmental conditions.

Air↗
PubMed1994

Growth and gas exchange by lettuce stands in a closed, controlled environment.

Two studies were conducted in which 'Waldmann's Green' lettuce (Lactuca sativa L.) was grown hydroponically from seed to harvest in a large (20-m2), atmospherically closed growth chamber for the National Aeronautics and Space Administration's controlled ecological life support system (CELSS) program. The first study used metal-halide (MH) lamps [280 micromoles m-2 s-1 photosynthetic photon flux (PPF)], whereas the second used high-pressure sodium (HPS) lamps (293 micromoles m-2 s-1). Both studies used a 16-hour photoperiod, a constant air temperature (22 to 23C), and 1000 micromoles mol-1 CO2 during the light period. In each study, canopy photosynthesis and evapotranspiration (ET) rates were highly correlated to canopy cover, with absolute rates peaking at harvest (28 days after planting ) at 17 micromoles CO2/m2 per sec and 4 liters m-2 day-1, respectively. When normalized for actual canopy cover, photosynthesis and ET rates per unit canopy area decreased with age (between 15 and 28 days after planting). Canopy cover increased earlier during the study with HPS lamps, and final shoot yields averaged 183 g fresh mass (FM)/plant 8.8 g dry mass (DM)/plant. Shoot yields in the first study with MH lamps averaged 129 g FM/plant and 6.8 g DM/plant. Analysis of leaf tissue showed that ash levels from both studies averaged 22% and K levels ranged from 15% to 17% of tissue DM. Results suggest that lettuce should be easily adaptable to a CELSS with moderate lighting and that plant spacing or transplant schemes are needed to maximize canopy light interception and sustained efficient CO2 removal and water production.

Biomass↗