Precise Environmental Control Research Articles

Culture of insect cells contracting spontaneously; research moving toward an environmentally robust hybrid robotic system

Here we propose an environmentally robust hybrid (biotic–abiotic) robotic system that uses insect heart cells. Our group has already presented a hybrid actuator using rat heart muscle cells, but it is difficult to keep rat heart muscle cells contracting spontaneously without maintaining the culture conditions carefully. Insect cells, by contrast, are robust over a range of culture conditions (temperature, osmotic pressure and pH) compared to mammalian cells. Therefore, a hybrid robotic system using not mammalian cells but insect cells can be driven without precise environmental control. As a first step toward the realization of this robotic system, the larvae of two lepidopteran species, Bombyx mori (BM) and Thysanoplusia intermixta (TI) were excised and the culture conditions of their dorsal vessel (insect heart) cells were examined. As a result, spontaneously contracting TI cells derived from the dorsal vessel were obtained. The contraction of TI cells started on the 7th day and continued for more than 18 days. Spontaneously contracting BM cells were not obtained in this study. These experimental results suggest the possibility of constructing an environmentally robust hybrid robotic system with living cells in the near future.

Using Air Pressure Cells to Evaluate the Effect of Soil Environment on the Transmission of Soilborne Viruses of Wheat

ABSTRACT An air pressure cell, a laboratory tool that precisely controls soil matric potential, was utilized in a novel approach to investigate the epidemiology and management of soilborne disease. Matric potentials of -1, -5, -20, and -40 kPa were established in cores of field soil infested with Wheat soilborne mosaic virus (WSBMV) and its presumed vector Polymyxa graminis. Equilibrated soil cores were planted to wheat (Triticum aestivum), and after intervals of growth under controlled environment, virus transmission was assessed by serological detection of the virus in washed roots. Transmission occurred at all but the driest soil matric potential tested, -40 kPa, in which only pores with a diameter of 7.4 mum or less were water-filled, possibly obstructing movement of P. graminis zoospores. By starting plants at -40 kPa for 10.5 days and then watering them to conducive matric potential, we found that WSBMV transmission occurred between 12 to 24 h at 15 degrees C, and within 36 h at 20 degrees C. No significant transmission occurred within 96 h at 6.5 degrees C. In contrast, transmission of Wheat spindle streak mosaic virus (WSSMV) did not occur at 15 degrees C (the only transmission temperature tested), suggesting either that WSSMV is unable to establish infection at 15 degrees C or that a different vector is involved. The air pressure cell is a novel tool with many potential applications in research on the epidemiology and management of soilborne pathogens. Applications of the precise environmental control attained through the use of air pressure cells range from assessing the effects of cultural practices on soilborne inoculum to standardized virulence assays for soilborne pathogens to preliminary screens of host resistance and pesticide efficacy.

Logical fallacies: A behavioral approach to reasoning.

Important phenomena in the area of judgment and decision making may be profitably studied with behavior-analytical techniques. We discuss three examples of such research: base-rate neglect, in which people ignore critical background in favor of less reliable case-specific information; the conjunction fallacy, in which people report that the conjunction of two events is more likely to have occurred than one of the events alone; and the sunk-cost effect, in which people are unwilling to abandon a course of action which has already incurred substantial cost. ********** When the area of human decision making (or judgment or choice) is mentioned, most psychologists assume that the reference is to the large body of work produced by cognitive and social psychologists. Since behavior analysis has long focused on (though most often in non-human subjects) it should have much to contribute to the discussion and analysis of human decisions. For example, the most recent Subject Index for the Journal of the Experimental Analysis of Behavior (November 2002, for volumes 61 through 78) has far more citations to choice than to any other content area. Most of these studies involve non-human subjects. Perhaps some behavior analysts understandably prefer the orderly functional relations produced by pigeons and other nonhuman subjects to the chaos and variability that often plagues research with humans. One reason for the variability, of course, is the difficulty in gaining precise environmental and historical control of human behavior (one of several gallant exceptions is the research of Bernstein & Ebbesen, 1978). But ostensibly aberrant human behavior can be a rich source for appreciating the dynamics of if we are able to pinpoint its determinants. Moreover, a comparison of human and non-human behavior in comparable settings can also prove illuminating. In this short paper we review some of the areas in which we are trying to better understand nortoptimal (and often irrational or illogical) human behavior. In so doing we will briefly review the status of several important phenomena that have been uncovered and largely monopolized by cognitive and social psychologists. We attempt to show that behavior analysis can contribute clarity to judgment and decision making. Our laboratory is currently exploring at least the following seven research areas involving human decisions: (1) probability matching (also probability learning) or the tendency, in a binary decision task, for humans to match their choices to the probabilities of the payoffs rather than maximizing reward by always choosing the more likely payoff (e.g., Fantino & Esfandiari, 2002); (2) information avoidance or the tendency of humans and nonhumans to prefer no news to bad news (e.g., Fantino & Case, 1983; Case, Ploog, & Fantino, 1990); (3) self-control as assessed in variants of the classic Prisoner's Dilemma Game, in which subjects maximize short-term gains at the expense of larger delayed payoffs (developed by Brown & Rachlin, 1999); (4) the effects of learning problems (including analogy and algebra problems) with and without rules (both induced and instructed rules) on transfer to different problems (e.g., Glaz, Stolarz-Fantino, and Fantino, 2001); (5) base-rate neglect in which people (but not pigeons) often ignore critical background in favor of less reliable case-specific information, when assessing the probability of a future event (e.g., Goodie & Fantino, 1995, 1996, 1999; Kalmeman & Tversky, 1973); (6) the conjunction fallacy, in which humans report that the conjunction of two events is more rather than less likely to have occurred than one of the events alone (e.g., Tversky & Kahneman, 1983; Stolarz-Fantino, Fantino, & Kulik, 1996; Stolarz-Fantino, Fantino, Zizzo, and Wen, 2003); (7) the sunk-cost effect, in which humans are unwilling to abandon a course of action which has already involved substantial cost (e. …

Controlled-Environment Sunlit Plant Growth Chambers

Controlled environment sunlit plant growth chambers have been built because of a great interest in plant responses to environmental variables under light intensities approaching those of natural sunlight conditions. Individual research projects have designed sunlit chambers that differ in size, structure, material, and environmental control systems dependent on the goals of the projects. Most literature describes plant organism responses to environmental variables, whereas reports of system design and performance are few. The objective of this article is to present a review of the engineering aspects of the design, environmental control, and performance of sunlit growth chambers that have been described in the literature. Most controlled environment sunlit growth chambers have been constructed with experimental plants grown in either pots or soil bins. Although a few sunlit growth chambers were designed for field grown plants, precise environmental control was not available. Further progress in the development of precise controlled environment sunlit growth chambers should include portability (or movability) so these chambers can be used in multiple field sites for greater cost-effectiveness. Modifications for improvements in guidelines for the design and operation of controlled environment growth chamber studies are also proposed.

Controlled-Environment Sunlit Plant Growth Chambers

Controlled environment sunlit plant growth chambers have been built because of a great interest in plant responses to environmental variables under light intensities approaching those of natural sunlight conditions. Individual research projects have designed sunlit chambers that differ in size, structure, material, and environmental control systems dependent on the goals of the projects. Most literature describes plant organism responses to environmental variables, whereas reports of system design and performance are few. The objective of this article is to present a review of the engineering aspects of the design, environmental control, and performance of sunlit growth chambers that have been described in the literature. Most controlled environment sunlit growth chambers have been constructed with experimental plants grown in either pots or soil bins. Although a few sunlit growth chambers were designed for field grown plants, precise environmental control was not available. Further progress in the development of precise controlled environment sunlit growth chambers should include portability (or movability) so these chambers can be used in multiple field sites for greater cost-effectiveness. Modifications for improvements in guidelines for the design and operation of controlled environment growth chamber studies are also proposed.

Chapter 28 Two-dimensional patterns of neural phosphoproteins from the rat labeled in vivo under anaesthesia, and in vitro in slices and synaptosomes

Publisher Summary Protein phosphorylation in intact cells may be studied both in vitro and in vivo . In vitro studies, using, for example, tissue slices have the advantage of permitting precise control of the immediate chemical environment of the cell, but are limited by the essentially unphysiological state of the tissue. In the in vivo situation, only very limited control over the cell environment is possible, but the tissue is subject to a degree of physiological regulation impossible to achieve in vitro . The actual extent of regulation clearly depends upon the state of the animal and currently systematic in vivo phosphorylation studies have been carried out almost entirely in anaesthetized animals. During these studies, two technical objectives were reported. The first was to develop methods for cell labeling that required, on the grounds of safety and economy, minimal amounts of 32 P radioactivity. The second objective was to employ the methods of analysis that would ensure that no dephosphorylation of labeled proteins occurred during sample preparation. This precluded subcellular fractionation of the tissue and necessitated analysis by high-resolution two-dimensional electrophoresis, in view of the complexity of phosphorylated substrates in whole tissue.

Understanding, Uncertainty and Robot Task Execution

Fundamental factors limiting the widespread application of current robotic systems are the requirements for precise control of the robot task environment, custom-designed fixtures and end-effectors, and on-site control program development. These requirements arise because current robotic systems do not have an understanding of the robot task environment. Further, these systems are not able to react intelligently to non-deterministic events which occur during task execution. This paper examines the nature of understanding and its use to resolve uncertainty as it relates to robot task execution. Then a research plan which is aimed at the systematic incorporation of understanding into the robot task environment is outlined.

Heptatic Response to Hyperthermia

Pettigrew et al. (1) proposed that above 41.8° C normal cells were subject to hyperthermic injury while at or below this temperature no serious cellular injury occurred. Cancer patients were maintained at this temperature for several hours, with little evidence of injury, in efforts to kill the more heat sensitive cancer cells. Inherent in this treatment regime was the theory that the duration of hyperthermic treatment at or below 41.8°C had no impact on injury to normal cells. Previous work in our laboratory, using the time course of enzyme leakage from isolated rat livers perfused with KRB at 37° C-43° C for 90 min, suggested that injury followed a time/temperature relationship. Ultrastructural, histological, and enzymatic data indicated that injury could occur below 41.8°C. Electron microscopy revealed celluar injury in livers which appeared normal by light microscopy. The time at which ultrastructural changes occurred at specific temperatures could not be determined since specimens were taken at the end of the perfusion experiments. In this study, livers were perfused for varing time intervals at temperatures from 41° C to 43° C, and these were compared with control livers perfused at 37° C for 90 min. The liver was chosen for this study because it is a common site of injury in both heatstroke and hyperthermic therapy. In addition, perfusion allows precise control of the organ's environment.

An installation for measuring carbon dioxide and water vapour exchange rates with a precise environmental control

An open system has been designed which enables a simple and rapid manual regulation of the CO2 concentration and absolute humidity in the assimilation chamber according to the actual CO2 and water vapour exchange rates, respectively. This ensures a constant effective CO2 concentration and humidity irrespective of the gas exchange of the leaves. The installation is supplemented with an irradiation system providing irradiance at the leaf level up to 3 200 μeinstein m−2s−1 (400–700 nm),i. e. ca. 675 W m−2.

One‐Degree Increments in Soil Temperatures Affect Maize Seedling Behavior

AbstractOne‐degree differences in soil temperatures, ranging from 12 to 35C, induced changes in the growth and nutritional behavior of maize seedlings (Zea mays L.) amounting to as much as 30 to 40% per degree. An improved system was developed to provide the precise environmental control required. The system provided for nearly isothermal control of soil temperatures even when soil and air temperatures differed by as much as 15C. The system also provided for uniform control of air temperature within ±0.7C and relative humidity within ±1% throughout the growing region in the 2 by 2.75 by 2 m growth chamber.With each degree increase in soil temperature from 12 to 26C, total seedling dry weights were an average of 20% greater than weights at each previous soil temperature and an average of 12% smaller with each degree increase from 26 to 35C. Nutritional status, leaf lengths and numbers, stem lengths, and root numbers also were very dependent upon soil temperature. Of special interest, a soil‐temperature‐dependent disorder resembling Ca deficiency was observed in the maize shoot. Also, the uptake of B was uniquely different from that of other elements. Surprisingly, the same total uptake of B occurred regardless of the soil temperature below 21C.The desirability of rigidly controlling soil temperature in pot experiments and the importance of minor changes in soil temperature on plant behavior have been clearly demonstrated.