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1

Recent Pacific Northwest Laboratory beagle and rodent studies  

SciTech Connect

Analyses based on data from two experimental studies conducted at Pacific Northwest Laboratory will be presented. The first is a lifespan study of beagle dogs exposed to inhaled plutonium. The objectives of this study are, first, to determine the biological effects in dogs of inhaled plutonium at various dose levels, and, second, to obtain dose-effect relationship data that can be used to estimate the risk of these effects in humans. In this study, eighteen-month-old beagle dogs were exposed through inhalation to six different levels and three different types of plutonium. The lowest level corresponds to the maximum permissible level for a plutonium worker, while the highest level is a level at which radiation pneumonitis is likely to cause early death. {sup 239}PuO{sub 2} was chosen because it is the form of plutonium to which people working in nuclear fuel processing and storage industries are likely to be exposed. {sup 238}PuO{sub 2} and {sup 239}Pu(NO{sub 3}){sub 4} were chosen because they result in different spatial and temporal distribution of radiation dose, and thus can provide information on the influence of these factors on risk. The second experiment is a lifespan study of rodents exposed through inhalation to radon and radon progeny. For the rodent experiments to be considered in this presentation, exposures were initiated at about 90 days of age at rates of 5, 50, and 500 WLM per week. Cumulative exposure levels were 320, 640, 1280, 2560, and 5120 WLM for animals exposed at 50 and 500 WLM per week, and 320 WLM for animals exposed at 5 WLM per week. 7 refs.

Gilbert, E.S.; Park, J.F.; Cross, F.C.; Dagle, G.E.

1990-07-01

2

In vivo effects of bisphenol A in laboratory rodent studies  

Microsoft Academic Search

Concern is mounting regarding the human health and environmental effects of bisphenol A (BPA), a high-production-volume chemical used in synthesis of plastics. We have reviewed the growing literature on effects of low doses of BPA, below 50 mg\\/(kg day), in laboratory exposures with mammalian model organisms. Many, but not all, effects of BPA are similar to effects seen in response

Catherine A. Richter; Linda S. Birnbaum; Francesca Farabollini; Retha R. Newbold; Beverly S. Rubin; Chris E. Talsness; John G. Vandenbergh; Debby R. Walser-Kuntz

3

In Vivo Effects of Bisphenol A in Laboratory Rodent Studies  

PubMed Central

Concern is mounting regarding the human health and environmental effects of bisphenol A (BPA), a high-production-volume chemical used in synthesis of plastics. We have reviewed the growing literature on effects of low doses of BPA, below 50 mg/kg/day, in laboratory exposures with mammalian model organisms. Many, but not all, effects of BPA are similar to effects seen in response to the model estrogens diethylstilbestrol and ethinylestradiol. For most effects, the potency of BPA is approximately 10 to 1,000-fold less than that of diethylstilbestrol or ethinylestradiol. Based on our review of the literature, a consensus was reached regarding our level of confidence that particular outcomes occur in response to low-dose BPA exposure. We are confident that adult exposure to BPA affects the male reproductive tract, and that long-lasting, organizational effects in response to developmental exposure to BPA occur in the brain, the male reproductive system, and metabolic processes. We consider it likely, but requiring further confirmation, that adult exposure to BPA affects the brain, the female reproductive system, and the immune system, and that developmental effects occur in the female reproductive system.

Richter, Catherine A.; Birnbaum, Linda S.; Farabollini, Francesca; Newbold, Retha R.; Rubin, Beverly S.; Talsness, Chris E.; Vandenbergh, John G.; Walser-Kuntz, Debby R.; vom Saal, Frederick S.

2007-01-01

4

Auditing laboratory rodent biosecurity programs.  

PubMed

A rodent biosecurity program that includes periodic evaluation of procedures used in an institution's vivarium can be used to ensure that best practices are in place to prevent a microbial pathogen outbreak. As a result of an ongoing comprehensive biosecurity review within their North American and European production facilities, the authors developed a novel biosecurity auditing process and worksheet that could be useful in other animal care and use operations. The authors encourage other institutions to consider initiating similar audits of their biosecurity programs to protect the health of their laboratory animals. PMID:24150170

Porter, William P; Horn, Mandy J; Cooper, Dale M; Klein, Hilton J

2013-10-22

5

The care and management of laboratory hystricomorph rodents  

Microsoft Academic Search

SUMMARY The caging, feeding and handling of four unusual laboratory hystricomorph rodents is described. These rodents are: the chinchilla (Chinchilla laniger), the agouti (Dasyprocta aguti), the acouchi (Myoprocta pratti), and the African porcupine (Hystrix cristata). The animals were kept for study of their reproduction and some details of this are given. The Hystricomorpha is a sub-order of the Order Rodentia

Barbara J. Weir

1967-01-01

6

Pinworm infections in laboratory rodents: a review  

Microsoft Academic Search

SUMMARY The important and common oxyurids which affect laboratory rodents- Syphacia spp., Aspiculuris tetraptera and Passafurus ambiguus-are discussed and reviewed. Their life histories, pathogenicity and immunity are examined, and mention is made of the influence of age, sex, strain and host status on in- fection. The importance of using worm-free animals in experimental work is stressed, and guidance is given

L. F. Taffs

1976-01-01

7

Pinworm infections in laboratory rodents: a review.  

PubMed

The important and common oxyurids which affect laboratory rodents- Syphacia spp., Aspiculuris tetraptera and Passalurus ambiguus-are discussed and reviewed. Their life histories, pathogenicity and immunity are examined, and mention is made of the influence of age, sex, strain and host status on infection. The importance of using worm-free animals in experimental work is stressed, and guidance is given on diagnosis and control. PMID:768631

Taffs, L F

1976-01-01

8

Utility of recycled bedding for laboratory rodents.  

PubMed

Animal facilities generate a large amount of used bedding containing excrement as medical waste. We developed a recycling system for used bedding that involves soft hydrothermal processing. In this study, we examined the effects of bedding type on growth, hematologic and serum biochemical values, and organ weights of female and male mice reared on either recycled or fresh bedding from 3 to 33 wk of age. Neither growth nor physiology differed between mice housed on recycled bedding compared with fresh bedding. When 14-wk-old mice were bred, litter size and total number of weaned pups showed no significant differences between animals raised on recycled or fresh bedding. Because bedding type influences the environment within cages and animal rooms, we evaluated particulate and ammonia data from cages and animal rooms. Values were significantly lower from cages and rooms that used recycled bedding than from those using fresh bedding, thus indicating that recycled bedding has the potential to improve the environment within both cages and animal rooms. Overall, this study revealed that recycled bedding is an excellent material for use in housing laboratory rodents. Specifically, recycled bedding may reduce medical waste and maintain healthy environments within cages and animal rooms. PMID:19653951

Miyamoto, Toru; Li, Zhixia; Kibushi, Tomomi; Okano, Shinya; Yamasaki, Nakamichi; Kasai, Noriyuki

2009-07-01

9

Brain acetylcholinesterase activity recovery following acute methyl parathion intoxication in two feral rodent species: comparison to laboratory rodents  

SciTech Connect

Widespread use of organophosphorus insecticides (OPs) has produced both acute and chronic intoxication among nontarget organisms. Most such studies have included fish and birds as opposed to mammals. However, numerous OP toxicity studies have been conducted on laboratory rodents creating a temptation to apply this data to feral rodents. Chronic OP exposure has been reported to produce cholinergic adaptation which in turn lowers mortality rates following a subsequent acute anticholinesterase exposure. The relevance that these laboratory rodent studies have on feral rodents is subject to debate. Field studies involving OP exposure among nontarget feral mammals have produced contradictory results. Increased mortality as a result of repeated OP application has been reported. This observation may be of considerable importance to nontarget feral rodent populations due to the repetitive nature of OP application protocols. The ability of feral rodents to recover brain AChE activity (BAA) between OP application intervals undoubtedly promotes their survival. This study investigated and compared BAA recovery following acute oral methyl parathion intoxication among 2 feral rodent species and among 2 common laboratory rodent species.

Roberts, D.K.; Silvey, N.J.; Bailey, E.M. Jr.

1988-07-01

10

Laboratory Rodent Welfare: Thinking Outside the Cage  

Microsoft Academic Search

This commentary presents the case against housing rats and mice in laboratory cages; the commentary bases its case on their sentience, natural history, and the varied detriments of laboratory conditions. The commentary gives 5 arguments to support this position: (a) rats and mice have a high degree of sentience and can suffer, (b) laboratory environments cause suffering, (c) rats and

Jonathan Balcombe

2010-01-01

11

Breath-hold device for laboratory rodents undergoing imaging procedures.  

PubMed

The increased use in noninvasive imaging of laboratory rodents has prompted innovative techniques in animal handling. Lung imaging of rodents can be a difficult task because of tissue motion caused by breathing, which affects image quality. The use of a prototype flat-panel computed tomography unit allows the acquisition of images in as little as 2, 4, or 8 s. This short acquisition time has allowed us to improve the image quality of this instrument by performing a breath-hold during image acquisition. We designed an inexpensive and safe method for performing a constant-pressure breath-hold in intubated rodents. Initially a prototypic manual 3-way valve system, consisting of a 3-way valve, an air pressure regulator, and a manometer, was used to manually toggle between the ventilator and the constant-pressure breath-hold equipment. The success of the manual 3-way valve system prompted the design of an electronically actuated valve system. In the electronic system, the manual 3-way valve was replaced with a custom designed 3-way valve operated by an electrical solenoid. The electrical solenoid is triggered by using a hand-held push button or a foot pedal that is several feet away from the gantry of the scanner. This system has provided improved image quality and is safe for the animals, easy to use, and reliable. PMID:16884181

Rivera, Belinda; Bushman, Mark J; Beaver, Richard G; Cody, Dianna D; Price, Roger E

2006-07-01

12

Isolation of Actinobacillus lignieresii and Actinobacillus equuli from laboratory rodents.  

PubMed

Actinobacillus lignieresii and Actinobacillus equuli were cultured from a total of 36 guinea pigs, rats, and mice. The organisms were isolated from the oropharynx, the conjunctiva, and middle ear. Isolates were initially screened by eight biochemical tests to determine whether they were of the genus Actinobacillus. Actinobacillus spp. were then differentiated by fermentation reactions of nine carbohydrates. In the past, actinobacilli may have been mistakenly identified as Pasteurella spp., especially Pasteurella pneumotropica. The importance of realizing that Actinobacillus spp. are frequently isolated from laboratory rodents was stressed. PMID:7217333

Lentsch, R H; Wagner, J E

1980-09-01

13

Isolation of Actinobacillus lignieresii and Actinobacillus equuli from laboratory rodents.  

PubMed Central

Actinobacillus lignieresii and Actinobacillus equuli were cultured from a total of 36 guinea pigs, rats, and mice. The organisms were isolated from the oropharynx, the conjunctiva, and middle ear. Isolates were initially screened by eight biochemical tests to determine whether they were of the genus Actinobacillus. Actinobacillus spp. were then differentiated by fermentation reactions of nine carbohydrates. In the past, actinobacilli may have been mistakenly identified as Pasteurella spp., especially Pasteurella pneumotropica. The importance of realizing that Actinobacillus spp. are frequently isolated from laboratory rodents was stressed.

Lentsch, R H; Wagner, J E

1980-01-01

14

Estimation of Wildlife Hazard Levels Using Interspecies Correlation Models and Standard Laboratory Rodent Toxicity Data  

EPA Science Inventory

Toxicity data from laboratory rodents are widely available and frequently used in human health assessments as an animal model. We explore the possibility of using single rodent acute toxicity values to predict chemical toxicity to a diversity of wildlife species and to estimate ...

15

The Role of Pheromonal Responses in Rodent Behavior: Future Directions for the Development of Laboratory Protocols  

PubMed Central

Pheromones—chemical signals that can elicit responses in a conspecific—are important in intraspecies communication. Information conveyed by pheromones includes the location of an animal, the presence of food or a threat, sexual attraction, courtship, and dam–pup interactions. These chemical messages remain intact and volatile even when animals, such as rodents, are housed in laboratories rather than their natural environment. Laboratory protocols, such as the cage cleaning and sanitation processes, as well as general housing conditions can alter a rodent's normal production of pheromones in both amount and type and thus may affect behavior. In addition, some procedures induce the release of alarm pheromones that subsequently alter the behavior of other rodents. To prevent pheromonal interference and stress-induced pheromonal release in their research subjects, experimenters should assess current laboratory protocols regarding cage cleaning processes, housing designs, and behavioral assays. Here we discuss how the most commonly used laboratory procedures can alter pheromonal signaling and cause confounding effects.

Bind, Rebecca H; Minney, Sarah M; Rosenfeld, SaraJane; Hallock, Robert M

2013-01-01

16

Observations on Natural and Laboratory Infection of Rodents with the Etiologic Agent of Korean Hemorrhagic Fever.  

National Technical Information Service (NTIS)

Studies were conducted to define the natural host range of Korean hemorrhagic fever (KHF) agent in South Korea, and to identify colonized rodents susceptible to this infection. Eight species of field rodents were captured in areas of Korea endemic for KHF...

H. W. Lee G. R. French P. W. Lee L. J. Baek K. Tsuchiya

1980-01-01

17

Contactless area measurement of area edema in laboratory rodent paw: (Contactless Planimetry)  

Microsoft Academic Search

This paper describes the designed hardware and software systems (planimeters) for contactless measurement of areas (measuring the variation of oedema area's) of planar projections of laboratory rodent leap. These systems operate on the principle of processing the video signal scanned by a digital camera.

Said Ech-Chadi

2011-01-01

18

Early-stress regulates resilience, vulnerability and experimental validity in laboratory rodents through mother–offspring hormonal transfer  

Microsoft Academic Search

The role of early-life stressors in the calibration of individual responses to future challenges has long been investigated in laboratory rodents. Specifically, countless studies show that exposure to early-life stressors – in the form of various periods of maternal separation, administration of exogenous corticosterone and variable feeding conditions – modulate the regulation of defensive responses (e.g. behavioral fearfulness\\/anxiety and endocrine

Simone Macrì; Francesca Zoratto; Giovanni Laviola

2011-01-01

19

The role of pheromonal responses in rodent behavior: future directions for the development of laboratory protocols.  

PubMed

Pheromones--chemical signals that can elicit responses in a conspecific--are important in intraspecies communication. Information conveyed by pheromones includes the location of an animal, the presence of food or a threat, sexual attraction, courtship, and dam-pup interactions. These chemical messages remain intact and volatile even when animals, such as rodents, are housed in laboratories rather than their natural environment. Laboratory protocols, such as the cage cleaning and sanitation processes, as well as general housing conditions can alter a rodent's normal production of pheromones in both amount and type and thus may affect behavior. In addition, some procedures induce the release of alarm pheromones that subsequently alter the behavior of other rodents. To prevent pheromonal interference and stress-induced pheromonal release in their research subjects, experimenters should assess current laboratory protocols regarding cage cleaning processes, housing designs, and behavioral assays. Here we discuss how the most commonly used laboratory procedures can alter pheromonal signaling and cause confounding effects. PMID:23562094

Bind, Rebecca H; Minney, Sarah M; Rosenfeld, SaraJane; Hallock, Robert M

2013-03-01

20

Factors controlling the level and determination of D-amino acids in the urine and plasma of laboratory rodents  

Microsoft Academic Search

Unambiguous methodologies were developed for the accurate and reproducible determination of specific D-amino acids in the physiological fluids of common laboratory rodents. Depending on the strain of rodent and the type of amino acid examined, excreted D-amino acids ranged from the low percent levels to over 40 percent of the total specific amino acid level. Relative plasma levels tended to

D. W. Armstrong; M. P. Gasper; S. H. Lee; N. Ercal; J. Zukowski

1993-01-01

21

Mass Airflow Cabinet for Control of Airborne Infection of Laboratory Rodents  

PubMed Central

A mass airflow cabinet for handling and housing of laboratory rodents has been developed and tested. The unit consists of a high-efficiency particulate air filter and uniform distribution of air at a vertical velocity of 19 cm per s. Animals are maintained without bedding in mesh-bottomed cages that rest on rollers for rotation inside the cabinet. There is an air barrier of 90 cm per s separating the cabinet air from room air. Sampling for airborne bacteria yielded an average of 0.03 colony-forming units (CFU) per ft3 of air inside the cabinet, whereas 28.8 CFU per ft3 was simultaneously detected outside the cabinet during housekeeping, a reduction of almost three logs. The efficiency of the air barrier was tested by aerosolization of T3 phage. When phage was aerosolized 5 cm outside the cabinet, no phage could be detected 5 cm inside when the fans were operating; with the fans off an average of 1.6 × 104 plaque-forming units (PFU) per ft3 was detected in six tests. Aerosolization of phage inside the cabinet yielded an average of 9 × 10 PFU per ft3 outside; an average of 4.1 × 106 PFU per ft3 were detected with the fans not in operation, a reduction of more than four logs. In-use studies on effectiveness showed that the cabinet significantly reduced the incidence of mice originally titer-free to Reo-3 virus. Hemagglutination inhibition antibodies to Reo-3 were detected in 9/22 (42%) mice housed in a conventionally ventilated animal laboratory while no seroconversion was detected in any of 22 mice housed in the mass air flow cabinet in the same laboratory. Images

McGarrity, Gerard J.; Coriell, Lewis L.

1973-01-01

22

Rodents for comparative aging studies: from mice to beavers  

PubMed Central

After humans, mice are the best-studied mammalian species in terms of their biology and genetics. Gerontological research has used mice and rats extensively to generate short- and long-lived mutants, study caloric restriction and more. Mice and rats are valuable model organisms thanks to their small size, short lifespans and fast reproduction. However, when the goal is to further extend the already long human lifespan, studying fast aging species may not provide all the answers. Remarkably, in addition to the fast-aging species, the order Rodentia contains multiple long-lived species with lifespans exceeding 20 years (naked mole-rat, beavers, porcupines, and some squirrels). This diversity opens great opportunities for comparative aging studies. Here we discuss the evolution of lifespan in rodents, review the biology of slow-aging rodents, and show an example of how the use of a comparative approach revealed that telomerase activity coevolved with body mass in rodents.

Bozzella, Michael J.; Seluanov, Andrei

2008-01-01

23

CONCENTRATED AMBIENT PARTICULATE STUDIES IN HEALTHY AND COMPROMISED RODENTS  

EPA Science Inventory

CONCENTRATED AMBIENT PARTICULATE STUDIES IN HEALTHY AND COMPROMISED RODENTS. WP Watkinson1, LB Wichers2, JP Nolan1, DW Winsett1, UP Kodavanti1, MCJ Schladweiler1, LC Walsh1, ER Lappi1, D Terrell1, R Slade1, AD Ledbetter1, and DL Costa1. 1USEPA, ORD/NHEERL/ETD/PTB, RTP, NC, US...

24

New rodent models for studies of chemopreventive agents.  

PubMed

Some recent studies of the effects of chemopreventive agents have begun to use new rodent models to improve the analysis of stages of colonic preneoplasia, and how chemopreventive agents modify progressive abnormal cell development. In one of the models of inherited predisposition to colon cancer, mice carrying a truncated Apc allele with a nonsense mutation in exon 15 have been generated by gene targeting and embryonic stem cell technology (Apc1638 mice). These mice develop multiple gastrointestinal lesions, including adenomas and carcinomas, focal areas of high-grade dysplasia (FAD), and polypoid hyperplasias with FADS. The incidence of inherited colonic neoplasms has now been modulated by a chemopreventive regimen. Colonic lesions significantly increased in Apc1638 mice on a Western-style diet, which has higher fat content and lower calcium and vitamin D compared to the same mice on AIN-76A diet. In another rodent model, Min mice were treated with sulindac, which markedly reduced the incidence of intestinal tumors. A third new rodent model containing a targeted mutation in the gene Mcc (mutated in colorectal cancer) recently became available for chemoprevention studies. These mice develop multiple types of neoplasms including adenocarcinomas, focal areas of gastrointestinal dysplasia, papillomas of the forestomach, and tumors in other organs including lung, liver, and lymphoid tissue. Feeding a Western-style diet to the Mcc mutant mice also resulted in significantly increased gastrointestinal lesions. These nutrient modifications also have been given to normal mice, demonstrating without any chemical carcinogen that a Western-style diet induced colonic tumorigenesis. Western-style diets also have now induced modulation of cell proliferation in other organs including mammary gland, pancreas, and prostate. These findings help develop new preclinical rodent models to aid the analysis of genetic and environmental factors leading to neoplasia, as well as new methods for evaluating the chemopreventive efficacy of specific nutrients and pharmacological agents. PMID:9589360

Lipkin, M

1997-01-01

25

Two new rodent models for actinide toxicity studies. [/sup 237/Pu, /sup 241/Am  

SciTech Connect

Two small rodent species, the grasshopper mouse (Onychomys leucogaster) and the deer mouse (Peromyscus maniculatus), have tenacious and high retention in the liver and skeleton of plutonium and americium following intraperitoneal injection of Pu and Am in citrate solution. Liver retention of Pu and Am in the grasshopper mouse is higher than liver retention in the deer mouse. Both of these rodents are relatively long-lived, breed well in captivity, and adapt suitably to laboratory conditions. It is suggested that these two species of mice, in which plutonium retention is high and prolonged in both the skeleton and liver, as it is in man, may be useful animal models for actinide toxicity studies.

Taylor, G.N.; Jones, C.W.; Gardner, P.A.; Lloyd, R.D.; Mays, C.W.; Charrier, K.E.

1981-04-01

26

Rodent models to study the relationships between mammals and their bacterial inhabitants.  

PubMed

Laboratory rodents have been instrumental in helping researchers to unravel the complex interactions that mammals have with their microbial commensals. Progress in defining these interactions has also been possible thanks to the development of culture-independent methods for describing the microbiota associated to body surfaces. Understanding the mechanisms that govern this relationship at the molecular, cellular, and ecological levels is central to both health and disease. The present review of rodent models commonly used to investigate microbial-host "conversations" is focused on those complex bacterial communities residing in the lower gut. Although many types of pathology have been studied using gnotobiotic animals, only the models relevant to commensal bacteria will be described. PMID:22918304

Bibiloni, Rodrigo

2012-08-23

27

Rodent models to study the relationships between mammals and their bacterial inhabitants  

PubMed Central

Laboratory rodents have been instrumental in helping researchers to unravel the complex interactions that mammals have with their microbial commensals. Progress in defining these interactions has also been possible thanks to the development of culture-independent methods for describing the microbiota associated to body surfaces. Understanding the mechanisms that govern this relationship at the molecular, cellular, and ecological levels is central to both health and disease. The present review of rodent models commonly used to investigate microbial-host “conversations” is focused on those complex bacterial communities residing in the lower gut. Although many types of pathology have been studied using gnotobiotic animals, only the models relevant to commensal bacteria will be described.

2012-01-01

28

Ecologic studies of rodent reservoirs: their relevance for human health.  

PubMed Central

Within the past few years, the number of "new" human diseases associated with small-mammal reservoirs has increased dramatically, stimulating renewed interest in reservoir ecology research. A consistent, integrative approach to such research allows direct comparisons between studies, contributes to the efficient use of resources and data, and increases investigator safety. We outline steps directed toward understanding vertebrate host ecology as it relates to human disease and illustrate the relevance of each step by using examples from studies of hosts associated with rodent-borne hemorrhagic fever viruses.

Mills, J. N.; Childs, J. E.

1998-01-01

29

Field and experimental studies of poxvirus infections in rodents  

PubMed Central

Data are presented from serological and virological investigations of natural and experimental infections, in rodents, with different poxviruses. The demonstration of poxvirus antibodies (virus neutralizing antibodies, antihaemagglutinins, and precipitins) in the kidneys and/or lungs of rodents from Europe and Africa, and the isolation of poxviruses from them, all indicate that rodents may be poxvirus carriers. Isolates from rodents differed in their properties. Some, from Turkmenistan rodents or from white rats caught near Moscow, appeared to be very close to cowpox virus, while others (from Zaire rodents) were identical to variola-like (whitepox) viruses found earlier in monkeys in the same region. The results suggest that rodents that carry the virus closely similar to cowpox virus might be a source of infection for other animal species.

Marennikova, S. S.

1979-01-01

30

Retinal anatomy and visual performance in a diurnal cone-rich laboratory rodent, the Nile grass rat (Arvicanthis niloticus).  

PubMed

Unlike laboratory rats and mice, muridae of the Arvicanthis family (A. ansorgei and A. niloticus) are adapted to functioning best in daylight. To date, they have been used as experimental models mainly in studies of circadian rhythms. However, recent work aimed at optimizing photoreceptor-directed gene delivery vectors (Khani et al. [2007] Invest Ophthalmol Vis Sci 48:3954-3961) suggests their potential usefulness for studying retinal pathologies and therapies. In the present study we analyzed the retinal anatomy and visual performance of the Nile grass rat (A. niloticus) using immunohistofluorescence and the optokinetic response (OKR). We found that approximately 35-40% of photoreceptors are cones; that many neural features of the inner retina are similar to those in other diurnal mammals; and that spatial acuity, measured by the OKR, is more than two times that of the usual laboratory rodents. These observations are consistent with the known diurnal habits of this animal, and further support its pertinence as a complementary model for studies of structure, function, and pathology in cone-rich mammalian retinae. PMID:18680202

Gaillard, Frédéric; Bonfield, Stephan; Gilmour, Gregory S; Kuny, Sharee; Mema, Silvina C; Martin, Brent T; Smale, Laura; Crowder, Nathan; Stell, William K; Sauvé, Yves

2008-10-10

31

Anaesthesia and physiological monitoring during in vivo imaging of laboratory rodents: considerations on experimental outcomes and animal welfare  

PubMed Central

The implementation of imaging technologies has dramatically increased the efficiency of preclinical studies, enabling a powerful, non-invasive and clinically translatable way for monitoring disease progression in real time and testing new therapies. The ability to image live animals is one of the most important advantages of these technologies. However, this also represents an important challenge as, in contrast to human studies, imaging of animals generally requires anaesthesia to restrain the animals and their gross motion. Anaesthetic agents have a profound effect on the physiology of the animal and may thereby confound the image data acquired. It is therefore necessary to select the appropriate anaesthetic regime and to implement suitable systems for monitoring anaesthetised animals during image acquisition. In addition, repeated anaesthesia required for longitudinal studies, the exposure of ionising radiations and the use of contrast agents and/or imaging biomarkers may also have consequences on the physiology of the animal and its response to anaesthesia, which need to be considered while monitoring the animals during imaging studies. We will review the anaesthesia protocols and monitoring systems commonly used during imaging of laboratory rodents. A variety of imaging modalities are used for imaging rodents, including magnetic resonance imaging, computed tomography, positron emission tomography, single photon emission computed tomography, high frequency ultrasound and optical imaging techniques such as bioluminescence and fluorescence imaging. While all these modalities are implemented for non-invasive in vivo imaging, there are certain differences in terms of animal handling and preparation, how the monitoring systems are implemented and, importantly, how the imaging procedures themselves can affect mammalian physiology. The most important and critical adverse effects of anaesthetic agents are depression of respiration, cardiovascular system disruption and thermoregulation. When anaesthetising rodents, one must carefully consider if these adverse effects occur at the therapeutic dose required for anaesthesia, if they are likely to affect the image acquisitions and, importantly, if they compromise the well-being of the animals. We will review how these challenges can be successfully addressed through an appropriate understanding of anaesthetic protocols and the implementation of adequate physiological monitoring systems.

2012-01-01

32

Studying autism in rodent models: reconciling endophenotypes with comorbidities.  

PubMed

Autism spectrum disorder (ASD) patients commonly exhibit a variety of comorbid traits including seizures, anxiety, aggressive behavior, gastrointestinal problems, motor deficits, abnormal sensory processing, and sleep disturbances for which the cause is unknown. These features impact negatively on daily life and can exaggerate the effects of the core diagnostic traits (social communication deficits and repetitive behaviors). Studying endophenotypes relevant to both core and comorbid features of ASD in rodent models can provide insight into biological mechanisms underlying these disorders. Here we review the characterization of endophenotypes in a selection of environmental, genetic, and behavioral rodent models of ASD. In addition to exhibiting core ASD-like behaviors, each of these animal models display one or more endophenotypes relevant to comorbid features including altered sensory processing, seizure susceptibility, anxiety-like behavior, and disturbed motor functions, suggesting that these traits are indicators of altered biological pathways in ASD. However, the study of behaviors paralleling comorbid traits in animal models of ASD is an emerging field and further research is needed to assess altered gastrointestinal function, aggression, and disorders of sleep onset across models. Future studies should include investigation of these endophenotypes in order to advance our understanding of the etiology of this complex disorder. PMID:23898259

Argyropoulos, Andrew; Gilby, Krista L; Hill-Yardin, Elisa L

2013-07-25

33

Environmental Enrichment of Laboratory Rodents: The Answer Depends on the Question.  

National Technical Information Service (NTIS)

Efforts to refine the care and use of animals in research have been ongoing for many years and have led to general standardization of rodent models, particularly with regard to animal housing, genetics, and health status. Concurrently, numerous informal p...

K. Kregel L. Leon L. A. Toth T. I. Musch

2011-01-01

34

?-Cell Generation: Can Rodent Studies Be Translated to Humans?  

PubMed Central

?-cell replacement by allogeneic islet transplantation is a promising approach for patients with type 1 diabetes, but the shortage of organ donors requires new sources of ? cells. Islet regeneration in vivo and generation of ?-cells ex vivo followed by transplantation represent attractive therapeutic alternatives to restore the ?-cell mass. In this paper, we discuss different postnatal cell types that have been envisaged as potential sources for future ?-cell replacement therapy. The ultimate goal being translation to the clinic, a particular attention is given to the discrepancies between findings from studies performed in rodents (both ex vivo on primary cells and in vivo on animal models), when compared with clinical data and studies performed on human cells.

Carlotti, Francoise; Zaldumbide, Arnaud; Ellenbroek, Johanne H.; Spijker, H. Siebe; Hoeben, Rob C.; de Koning, Eelco J.

2011-01-01

35

A new rodent behavioral paradigm for studying forelimb movement  

PubMed Central

The center-out task is a standard paradigm often used to study the neural control of reaching movements in human and non-human primates. However, there are several disadvantages to the use of monkeys, notably costs, infrastructural requirements, and ethical considerations. Here we describe a similar task designed to examine forelimb movements in rats. Rats were trained to grasp a joystick with their forepaw and use it to control the movements of a sipper tube in two dimensions. The rats learned to move the joystick in four directions with at least 70% accuracy after about 45 days of training. In addition, rats were able to learn a reversed mapping between joystick and sipper tube movement. This is a more complicated behavior than has been previously demonstrated for rats, and it could allow more motor behavior studies to be conducted in rodents instead of monkeys. We currently are using this behavior to decode the rats’ forelimb movements from their brain signals.

Slutzky, Marc W.; Jordan, Luke R.; Bauman, Matthew J.; Miller, Lee E.

2010-01-01

36

Serological study of hantavirus in the rodent population of Nakhon Pathom and Nakhon Ratchasima Provinces Thailand.  

PubMed

A serological survey has been carried out to detect evidence of hantavirus infection in rodents from two provinces of Thailand. This study aimed to examine virus antibody in 354 rodents trapped among 6 different villages of Nakhon Pathom Province (February-March, 1998) and in 326 rodents trapped among 14 villages of Nakhon Ratchasima Province (August-October, 1998). Seroprevalence among rodents from Nakhon Pathom Province (2.3%), was mostly find in Rattus norvegicus (3.8%) and Bandicota indica (2.6%). In Nakhon Ratchasima Province seroprevalence (4.0%) was mostly in Bandicota indica (19.1%) and Rattus exulans (3.5%). PMID:11127326

Nitatpattana, N; Chauvancy, G; Dardaine, J; Poblap, T; Jumronsawat, K; Tangkanakul, W; Poonsuksombat, D; Yoksan, S; Gonzalez, J P

2000-06-01

37

Results from a Survey of Current Practices for Sampling of Nervous System in Rodents and Non-rodents in General Toxicity Studies  

EPA Science Inventory

A survey of current practices for sampling and examination of the nervous system in rodents and non-rodents for general and neurotoxicity (NT) studies was conducted by the Nervous System Sampling Subcommittee of the STP. For general toxicity studies most of those surveyed (>63%) ...

38

Use of historical control data in carcinogenicity studies in rodents.  

PubMed

This paper considers the use of historical control data in the evaluation of tumor incidences from carcinogenicity studies in rodents. Although the most appropriate control group for interpretative purposes is always the concurrent control, there are instances in which the use of historical control information can aid an investigator in the overall evaluation of tumor incidence data. One example is rare tumors; another is a tumor that shows a marginally significant result relative to concurrent controls. However, before historical control data can be used in a formal testing framework, a number of important issues must first be considered. The nomenclature conventions and diagnostic criteria for each study should be identical to insure unambiguous identification of all relevant tumors in the historical control database. Criteria should be established that will aid in determining whether a particular study should be included in the database. This will assure a homogeneous set of studies upon which to base statistical comparisons. Since study-to-study variability in tumor rates may exceed what would be expected by chance alone, these sources of variability should be identified and controlled. Finally, statistical procedures should be employed that adjust for extra-binomial variability. This paper also summarizes tumor incidence data from untreated Fischer 344 rats and B6C3F1 mice in the National Toxicology Program (NTP) historical control database. All studies in the database are of two years duration, and all neoplasms occurring with a frequency of 0.5% or more are reported. PMID:11478313

Haseman, J K; Huff, J; Boorman, G A

1984-01-01

39

Chemical-induced atrial thrombosis in NTP rodent studies.  

PubMed

Cardiac thrombosis, one of the causes of sudden death throughout the world, plays a principal role in several cardiovascular diseases, such as myocardial infarction and stroke in humans. Data from studies of induction of chemical thrombosis in rodents help to identify substances in our environment that may contribute to cardiac thrombosis. Results for more than 500 chemicals tested in rodents in 2-year bioassays have been published as Technical Reports of the National Toxicology Program (NTP) http://ntp-server.niehs.nih.gov/index. We evaluated atrial thrombosis induced by these chemical exposures and compared it to similarly induced lesions reported in the literature. Spontaneous rates of cardiac thrombosis were determined for control Fischer 344 rats and B6C3F1 mice: 0% in rats and mice in 90-day studies and, in 2-year studies, 0.7% in both genders of mice, 4% in male rats, and 1% in female rats. Incidences of atrial thrombosis were increased in high-dosed groups involving 13 compounds (incidence rate: 20-100%): 2-butoxyethanol, C.I. Direct Blue 15, bis(2-chloroethoxy)methane, diazoaminobenzene, diethanolamine, 3,3'-dimethoxybenzidine dihydrochloride, hexachloroethane, isobutene, methyleugenol, oxazepam, C.I. Pigment Red 23, C.I. Acid Red 114, and 4,4'-thiobis(6-t-butyl-m-cresol). The main localization of spontaneously occurring and chemically induced thromboses occurred in the left atrium. The literature survey suggested that chemical-induced atrial thrombosis might be closely related to myocardial injury, endothelial injury, circulatory stasis, hypercoagulability, and impaired atrial mechanical activity, such as atrial fibrillation, which could cause stasis of blood within the left atrial appendage, contributing to left atrial thrombosis. Supplementary data referenced in this paper are not printed in this issue of Toxicologic Pathology. They are available as downloadable files at http://taylorandfrancis.metapress.com/openurl.asp?genre=journal&issn=0192-6233. To access them, click on the issue link for 33(5), then select this article. A download option appears at the bottom of this abstract. In order to access the full article online, you must either have an individual subscription or a member subscription accessed through www.toxpath.org. PMID:16048847

Yoshizawa, Katsuhiko; Kissling, Grace E; Johnson, Jo Anne; Clayton, Natasha P; Flagler, Norris D; Nyska, Abraham

2005-01-01

40

Seed choice by rodents: learning or inheritance?  

Microsoft Academic Search

Learning plays a central role in animal life, and it has received special attention in the context of foraging. In this study,\\u000a we have tested whether learning operates in seed choices by rodents using the Algerian mouse (Mus spretus) and Holm oak (Quercus ilex) acorns as a model. At the laboratory, those rodents captured in the field during the acorn

Alberto Muñoz; Raúl Bonal

2008-01-01

41

The Complexity of Alcohol Drinking: Studies in Rodent Genetic Models  

PubMed Central

Risk for alcohol dependence in humans has substantial genetic contributions. Successful rodent models generally attempt to address only selected features of the human diagnosis. Most such models target the phenotype of oral administration of alcohol solutions, usually consumption of or preference for an alcohol solution versus water. Data from rats and mice for more than 50 years have shown genetic influences on preference drinking and related phenotypes. This paper summarizes some key findings from that extensive literature. Much has been learned, including the genomic location and possible identity of several genes influencing preference drinking. We report new information from congenic lines confirming QTLs for drinking on mouse chromosomes 2 and 9. There are many strengths of the various phenotypic assays used to study drinking, but there are also some weaknesses. One major weakness, the lack of drinking excessively enough to become intoxicated, has recently been addressed with a new genetic animal model, mouse lines selectively bred for their high and intoxicating blood alcohol levels after a limited period of drinking in the circadian dark. We report here results from a second replicate of that selection and compare them with the first replicate.

Phillips, Tamara J.; Belknap, John K.

2012-01-01

42

Lung Function Measurements in Rodents in Safety Pharmacology Studies  

PubMed Central

The ICH guideline S7A requires safety pharmacology tests including measurements of pulmonary function. In the first step – as part of the “core battery” – lung function tests in conscious animals are requested. If potential adverse effects raise concern for human safety, these should be explored in a second step as a “follow-up study”. For these two stages of safety pharmacology testing, both non-invasive and invasive techniques are needed which should be as precise and reliable as possible. A short overview of typical in vivo measurement techniques is given, their advantages and disadvantages are discussed and out of these the non-invasive head-out body plethysmography and the invasive but repeatable body plethysmography in orotracheally intubated rodents are presented in detail. For validation purposes the changes in the respective parameters such as tidal midexpiratory flow (EF50) or lung resistance have been recorded in the same animals in typical bronchoconstriction models and compared. In addition, the technique of head-out body plethysmography has been shown to be useful to measure lung function in juvenile rats starting from day two of age. This allows safety pharmacology testing and toxicological studies in juvenile animals as a model for the young developing organism as requested by the regulatory authorities (e.g., EMEA Guideline 1/2008). It is concluded that both invasive and non-invasive pulmonary function tests are capable of detecting effects and alterations on the respiratory system with different selectivity and area of operation. The use of both techniques in a large number of studies in mice and rats in the last years have demonstrated that they provide useful and reliable information on pulmonary mechanics in safety pharmacology and toxicology testing, in investigations of respiratory disorders, and in pharmacological efficacy studies.

Hoymann, Heinz Gerd

2012-01-01

43

Intracranial self-stimulation (ICSS) in rodents to study the neurobiology of motivation  

Microsoft Academic Search

It has become increasingly important to assess mood states in laboratory animals. Tests that reflect reward, reduced ability to experience reward (anhedonia) and aversion (dysphoria) are in high demand because many psychiatric conditions that are currently intractable in humans (e.g., major depression, bipolar disorder, addiction) are characterized by dysregulated motivation. Intracranial self-stimulation (ICSS) can be utilized in rodents (rats, mice)

Elena H Chartoff; William A Carlezon

2007-01-01

44

Laboratory microfusion capability study  

SciTech Connect

The purpose of this study is to elucidate the issues involved in developing a Laboratory Microfusion Capability (LMC) which is the major objective of the Inertial Confinement Fusion (ICF) program within the purview of the Department of Energy's Defense Programs. The study was initiated to support a number of DOE management needs: to provide insight for the evolution of the ICF program; to afford guidance to the ICF laboratories in planning their research and development programs; to inform Congress and others of the details and implications of the LMC; to identify criteria for selection of a concept for the Laboratory Microfusion Facility and to develop a coordinated plan for the realization of an LMC. As originally proposed, the LMC study was divided into two phases. The first phase identifies the purpose and potential utility of the LMC, the regime of its performance parameters, driver independent design issues and requirements, its development goals and requirements, and associated technical, management, staffing, environmental, and other developmental and operational issues. The second phase addresses driver-dependent issues such as specific design, range of performance capabilities, and cost. The study includes four driver options; the neodymium-glass solid state laser, the krypton fluoride excimer gas laser, the light-ion accelerator, and the heavy-ion induction linear accelerator. The results of the Phase II study are described in the present report.

Not Available

1993-05-01

45

The Complexity of Alcohol Drinking: Studies in Rodent Genetic Models  

Microsoft Academic Search

Risk for alcohol dependence in humans has substantial genetic contributions. Successful rodent models generally attempt to\\u000a address only selected features of the human diagnosis. Most such models target the phenotype of oral administration of alcohol\\u000a solutions, usually consumption of or preference for an alcohol solution versus water. Data from rats and mice for more than\\u000a 50 years have shown genetic influences

John C. CrabbeTamara; Tamara J. Phillips; John K. Belknap

2010-01-01

46

The electroretinogram (ERG) of a diurnal cone-rich laboratory rodent, the Nile grass rat (Arvicanthis niloticus).  

PubMed

The most widespread models to study blindness, rats and mice, have retinas containing less than 3% cones. The diurnal rodent Arvicanthis niloticus retina has around 35% cones. Using ERG recordings, we studied retina function in this species. Several features differed from that reported in rats and mice: (a) fivefold larger photopic a-wave amplitudes; (b) photopic hill effect in Nile grass rats only; and (c) flicker amplitude plateau between 5 to 35 Hz with fusion beyond 60 Hz in Nile grass rats only. We conclude that A. niloticus might complement rats and mice for studying retinal function and pathologies involving cones. PMID:18824014

Gilmour, Gregory S; Gaillard, Frédéric; Watson, Juliane; Kuny, Sharee; Mema, Silvina C; Bonfield, Stephan; Stell, William K; Sauvé, Yves

2008-10-19

47

Potential clinical translation of juvenile rodent inactivity models to study the onset of childhood obesity  

PubMed Central

According to the latest data from the Center for Disease Control and Prevention 17%, or 12.5 million, of children and adolescents aged 2–19 years in the United States are obese. Physical inactivity is designated as one of the actual causes of US deaths and undoubtedly contributes to the obesity epidemic in children and adults. Examining the effects of inactivity on physiological homeostasis during youth is crucial given that 58% of children between the ages 6–11 yr old fail to obtain the recommended 60 min/day of physical activity and 92% of adolescents fail to achieve this goal [Troiano et al. Med Sci Sports Exerc. 40, 2008]. Nonetheless, invasive mechanistic studies in children linking diminished physical activity with metabolic maladies are lacking for obvious ethical reasons. The rodent wheel lock (WL) model was adopted by our laboratory and others to study how different organ systems of juvenile rats respond to a cessation of daily physical activity. Our WL model houses rats in cages equipped with voluntary running wheels starting at 28 days of age. After a certain period of voluntary running (3 to 6 wk), the wheels are locked, thus preventing the rats' primary source of physical activity. The studies discussed herein suggest that obesity-associated maladies including skeletal muscle insulin resistance, hypothalamic leptin resistance, fatty acid oxidation impairments in skeletal muscle and adipose tissue, nonalcoholic fatty liver disease, and endothelial dysfunction are initiated in juvenile animals that are restrained from voluntary exercise via WL. The use of the juvenile rodent WL or other inactivity models will continue to provide a powerful clinical translational tool that can be used for primordial prevention of human childhood obesity.

Roberts, Michael D.; Company, Joseph M.; Brown, Jacob D.; Toedebusch, Ryan G.; Padilla, Jaume; Jenkins, Nathan T.; Laughlin, M. Harold

2012-01-01

48

Eliminating animal facility light-at-night contamination and its effect on circadian regulation of rodent physiology, tumor growth, and metabolism: a challenge in the relocation of a cancer research laboratory.  

PubMed

Appropriate laboratory animal facility lighting and lighting protocols are essential for maintaining the health and wellbeing of laboratory animals and ensuring the credible outcome of scientific investigations. Our recent experience in relocating to a new laboratory facility illustrates the importance of these considerations. Previous studies in our laboratory demonstrated that animal room contamination with light-at-night (LAN) of as little as 0.2 lx at rodent eye level during an otherwise normal dark-phase disrupted host circadian rhythms and stimulated the metabolism and proliferation of human cancer xenografts in rats. Here we examined how simple improvements in facility design at our new location completely eliminated dark-phase LAN contamination and restored normal circadian rhythms in nontumor-bearing rats and normal tumor metabolism and growth in host rats bearing tissue-isolated MCF7(SR(-)) human breast tumor xenografts or 7288CTC rodent hepatomas. Reducing LAN contamination in the animal quarters from 24.5 ± 2.5 lx to nondetectable levels (complete darkness) restored normal circadian regulation of rodent arterial blood melatonin, glucose, total fatty and linoleic acid concentrations, tumor uptake of O(2), glucose, total fatty acid and CO(2) production and tumor levels of cAMP, triglycerides, free fatty acids, phospholipids, and cholesterol esters, as well as extracellular-signal-regulated kinase, mitogen-activated protein kinase, serine-threonine protein kinase, glycogen synthase kinase 3?, ?-histone 2AX, and proliferating cell nuclear antigen. PMID:21640027

Dauchy, Robert T; Dupepe, Lynell M; Ooms, Tara G; Dauchy, Erin M; Hill, Cody R; Mao, Lulu; Belancio, Victoria P; Slakey, Lauren M; Hill, Steven M; Blask, David E

2011-05-01

49

VDTs: Field levels, epidemiology, and laboratory studies  

SciTech Connect

As the use of video display terminals (VDTs) has expanded, questions have been raised as to whether working at a VDT affects the risk of adverse pregnancy outcome. A particular focus for these questions has been the very low frequency (VLF) magnetic field produced by a VDT's horizontal deflection coil. VDTs also produce VLF electric fields, extremely low frequency (ELF) electric and magnetic fields, and static electric fields, Ten studies of pregnancy outcome in VDT operators have been conducted in six countries, and with one exception, none has concluded that magnetic fields from VDTs may predispose pregnant operators to spontaneous abortion or congenital malformation. The epidemiologic studies conducted thus far do not provide a basis for concluding that VDT work and adverse pregnancy outcome are associated. Studies of fetal resorptions and malformations in rodents exposed to VLF magnetic fields have produced inconsistent findings. Two laboratories in Sweden that studied mice have reported positive results, one laboratory showing field-related malformations (but not resorptions) and the other showing field-related resorptions (but not malformations). Two Canadian laboratories have reported negative results in rats and mice. Studies of avian embryos have also yielded inconsistent results, but lacking a maternal-fetal placental interface, avian embryos are a questionable model for evaluating human reproductive risks. Finally, VLF electric and magnetic fields measured at the operator position are in compliance with field strength standards and guidelines that have been established around the world. 55 refs.

Kavet, R.; Tell, R.A. (Richard Tell Associates, Inc., Las Vegas, NV (USA))

1991-07-01

50

Studies on the life history and development of Cuterebra polita (Diptera: Cuterebridae) in four species of rodents  

USGS Publications Warehouse

Cuterebra polita Coquillett is a primary parasite of the pocket gopher, Thomomys talpoides, in the western United States. It also occurs secondarily in other wild rodents that come into close contact with pocket gophers.Field studies disclosed pursuit, mating, and ovipositing at an aggregation site near Monte Cristo, Utah. Eggs were individually attached to fibrous roots suspended from the roof of shallow gopher burrows. This refinement of the host-parasite relationship has not previously been described for other North American cuterebrids.In the laboratory, 3 gravid females produced 186-357 viable eggs; about 85% were induced to hatch or hatched spontaneously after 12 days. Dissection of 1 of the females revealed another 886 eggs, for a total of 1243.Larvae were artificially introduced and developed in deer mice (Peromyscus maniculatus), domestic mice (Mus musculus), hamsters (Mesocricetus auratus), and meadow voles (Microtus montanus). The domestic rabbit (Orystolagus cuniculus) appeared refractory. The rate and success of development in the 4 rodent species was variable, but terminal larval development averaged about 22 days. Warbles appeared after 8 days in the rodents, and the majority of the cysts occurred in the posterior dorsal region.On the basis of larval characteristics, C. polita and C. thomomuris appear to be independent, valid species, though they share a common host.

Capelle, K. J.

1970-01-01

51

The effects of prenatal alcohol exposure on behavior: rodent and primate studies.  

PubMed

The use of alcohol by women during pregnancy is a continuing problem. In this review the behavioral effects of prenatal alcohol from animal models are described and related to studies of children and adults with FASD. Studies with monkeys and rodents show that prenatal alcohol exposure adversely affects neonatal orienting, attention and motor maturity, as well as activity level, executive function, response inhibition, and sensory processing later in life. The primate moderate dose behavioral findings fill an important gap between human correlational data and rodent mechanistic research. These animal findings are directly translatable to human findings. Moreover, primate studies that manipulated prenatal alcohol exposure and prenatal stress independently show that prenatal stress exacerbates prenatal alcohol-induced behavioral impairments, underscoring the need to consider stress-induced effects in fetal alcohol research. Studies in rodents and primates show long-term effects of prenatal and developmental alcohol exposure on dopamine system functioning, which could underpin the behavioral effects. PMID:21499982

Schneider, Mary L; Moore, Colleen F; Adkins, Miriam M

2011-04-19

52

Carcinogenicity of airborne combustion products observed in subcutaneous tissue and lungs of laboratory rodents.  

PubMed Central

Most air pollution in West Germany is caused by combustion products. Particulate organic matter released by incomplete combustion is suspected to contribute to the "urban factor" of lung cancer frequency in urban-industrial centers. The carcinogenic potential of single components, groups of compounds and total source emissions of combustion processes was investigated in laboratory animals by subcutaneous injection, intratracheal instillation or inhalation. Tests by subcutaneous injection of condensates of automobile exhaust, extracts of coal furnace emissions and of airborne particles and different fractions of these extracts showed that the polycyclic aromatic hydrocarbons (PAH) with four to six benzene rings have the strongest experimental carcinogenicity. However, polar compounds (heterocyclic nitrogen-containing PAH, phenols, and others) also show remarkable carcinogenic potency. There were large differences between the dose-response relationships of several PAHs. In the subcutaneous tissue, benzo(a)pyrene and dibenz(a,h)anthracene are the most carcinogenic of the tested airborne PAHs. Furthermore, they can induce high tumor rates in the lung after subcutaneous injection in newborn mice and after intratracheal instillation of mice or hamsters. The tumor rate of benzo(a)pyrene did not further increase after simultaneous instillation of carbon black, but lead chloride may have a promoting effect. Far more than 100 PAHs are found in the urban atmosphere. However, because of the remarkable similarity of the PAH profiles in the examined samples, it may be sufficient to measure just a few stable PAHs in the urban air in order to facilitate an assessment of the carcinogenic potency of the PAH content in the atmosphere. To examine the carcinogenic or cocarcinogenic effects of gas and vapor emissions, studies with a two-phase model were carried out: phase 1 relates to the induction of a basic tumor rate in the lung by a well known carcinogen, while phase 2 is characterized by an inhalation of the substance under investigation. In an experiment with mice, the inhalation of a mixture of SO2 and NO2 seemed to increase the basic tumor rate induced by dibenz(a,h)anthracene. In a similar two-phase experiment conducted with hamsters, the inhalation of diesel exhaust (total exhaust as well as exhaust without particles) increased a basic tumor rate induced by diethyl nitrosamine. These experiments deserve confirmation before a detailed interpretation is attempted.

Pott, F; Stober, W

1983-01-01

53

Zinc, the Pancreas, and Diabetes: Insights from Rodent Studies and Future Directions  

Microsoft Academic Search

Molecular and cellular studies have demonstrated several roles for zinc (Zn) in insulin production and the consequent actions of insulin on metabolism. Clinical and epidemiological studies suggest that reduced Zn status is associated with diabetes. Investigations of Zn in rodent models of diabetes have provided a valuable link for understanding the molecular, cellular, clinical and epidemiological observations in the context

Carla G. Taylor

2005-01-01

54

Rodent-repellent studies. III. Advanced studies in the evaluation of chemical repellents  

USGS Publications Warehouse

In order to bridge the gap between preliminary screening of chemicals for potential rodent repellency and the application ofthese compounds to paper cartons, more advanced studies in the evaluation ofpromising materials have been carried out. These studies have resulted in: (1) a modification of the food acceptance technique which eliminates doubtful compounds and also provides a closer analogy to the ultimate goal, and (2) a method for rapidly testing chemicals incorporated in paper. When the results of these latter tests are expressed as a function of time, it can be shown that a distinct correlation exists between the deterrency exhibited by treated paper and the repellency of treated food.

Bellack, E.; DeWitt, J.B.

1949-01-01

55

Laboratory study on \\  

Microsoft Academic Search

Background  It has been reported that pumping a shunt in situ may precipitate a proximal occlusion, and\\/or lead to ventricular over-drainage, particularly in the context of small ventricles.\\u000a In the laboratory we measured the effect of pumping the pre-chamber of hydrocephalus shunts on intracranial hypotension.\\u000a \\u000a \\u000a \\u000a \\u000a Materials and methods  A simple physical model of the CSF space in a hydrocephalic patient was constructed

Adam Bromby; Zofia Czosnyka; David Allin; Hugh K Richards; John D Pickard; Marek Czosnyka

2007-01-01

56

Issues in the Design and Interpretation of Chronic Toxicity and Carcinogenicity Studies in Rodents: Approaches to Dose Selection  

EPA Science Inventory

For more than three decades chronic studies in rodents have been the benchmark for assessing the potential long-term toxicity, and particularly the carcinogenicity, of chemicals. With doses typically administered for about 2 years (18 months to lifetime), the rodent bioassay has ...

57

Serological study of rickettsial diseases in human and rodent population in Chittoor dist. (A.P.).  

PubMed

In India the presence of Rickettsial disease in human is documented in many states however, the data on presence of Rickettsial infection in Andhra Pradesh is very scare. Therefore, a study was undertaken in Chittoor district (A.P.) to see the prevalence of Rickettsial infection in human and rodent population. 3-5 ml of human blood samples were collected from the patients attending the nearest hospitals of Tirumala, Tirupathi, Palmner and Chittoor areas. Live rodents were trapped and blood samples were collected from them during January and February 2008. Sera was separated and tested by Weil Felix test. Two hundred human sera samples were tested. Of these 39 samples were found reactive with Weil Felix antigen. Of the 39 reactive, 31 were male and 8 female. All the human samples were showing reactivity at 1:20 dilution. Out of the 343 rodents samples tested, only 24 samples were showing reactivity. These were reactive at 1:20, 1:40 and 1:80 dilutions with different types of Weil Felix antigens. Eight rodent sera samples were having titer 1:80 with Proteus OXK which is suggestive of presence of Scrub typhus in this region. PMID:22471185

Prabhakaran, A; Lal, Sohan; Biswas, Shyamal; Vinoth, S; Asraf, Ali S; Mittal, Veena

2010-09-01

58

Tethered Gravity Laboratories Study.  

National Technical Information Service (NTIS)

The scope of the study is to investigate ways of controlling the microgravity environment of the International Space Station by means of a tethered system. Four main study tasks were performed. First, researchers analyzed the utilization of the tether sys...

F. Lucchetti

1990-01-01

59

Rodent Control  

ERIC Educational Resources Information Center

Strategies for rodent control in crop fields, threshing yards, and rural residential areas are presented together with an operational plan for implementing a program for rodent control at the national level. Training personnel in rodent control procedures and procedures for educating the public in the necessity for control are covered. (EC)

Indian Journal of Adult Education, 1975

1975-01-01

60

Frontiers in population ecology of microtine rodents: A pluralistic approach to the study of population ecology  

Microsoft Academic Search

Current challenges for the study of population ecology of microtine rodents are reviewed. Comparisons with other taxonomic\\u000a groups (other mammals, birds and insects) are given throughout. A major challenge is to link patterns and processes (i.e.\\u000a mechanisms) better than is the case today. Other major challenges include the furthering of our understanding of the interaction\\u000a between deterministic and stochastic processes,

Nils Chr Stenseth; Takashi Saitoh; Nigel G. Yoccoz

1998-01-01

61

Rodents for comparative aging studies: from mice to beavers  

Microsoft Academic Search

After humans, mice are the best-studied mammalian species in terms of their biology and genetics. Gerontological research\\u000a has used mice and rats extensively to generate short- and long-lived mutants, study caloric restriction and more. Mice and\\u000a rats are valuable model organisms thanks to their small size, short lifespans and fast reproduction. However, when the goal\\u000a is to further extend the

Vera Gorbunova; Michael J. Bozzella; Andrei Seluanov

2008-01-01

62

Comparative study on the forefoot and hindfoot intrinsic muscles of some cavioidea rodents (Mammalia, Rodentia).  

PubMed

The present study compares the forefoot and hindfoot musculature of five representative species of Cavioidea rodents. In all species, the musculature of both forefeet and hindfeet have the same array regardless of the absence of digit I in the manus of Hydrochaeris hydrochaeris and Cavia porcellus. Our results suggest a tendency in these species towards a three-digit system, with a functional loss of digit V and a predominance of digit III in their forefeet. In the same way, the muscular reduction of digit I in the other rodents analyzed indicates a four-digit system with predominance of digit II in Myoprocta acouchy and Dasyprocta leporina and of digit V in Agouti paca. There seems to be an association between the muscular arrangement and functional axis of the foot, raising the general question why this axis runs between the third and forth digit, or along the third digit. PMID:17008077

Rocha-Barbosa, Oscar; Loguercio, Mariana F C; Renous, Sabine; Gasc, Jean-Pierre

2006-09-27

63

Inhalation studies of the genotoxicity of trichloroethylene to rodents.  

PubMed

Trichloroethylene (TCE) (CAS No. 79-01-6) is an industrial solvent used in degreasing, dry cleaning, and numerous other medical and industrial processes. Controlled inhalation studies were performed using male C57BL/6 mice and CD rats to determine if TCE can induce cytogenetic damage in vivo. Animals were exposed in groups of five to target concentrations of either 0, 5, 500, or 5000 ppm TCE for 6 h. Tissue samples were taken between 18 and 19 h post exposure. Peripheral blood lymphocytes (PBLs) in rats and splenocytes in mice were cultured and analyzed for the induction of sister-chromatid exchanges, chromosome aberrations, and micronuclei (MN) in cytochalasin B-blocked binucleated cells. Bone marrow polychromatic erythrocytes (PCEs) were analyzed for MN. The only positive response observed was for MN in rat bone marrow PCEs. TCE caused a statistically significant increase in MN at all concentrations, inducing an approximate fourfold increase over control levels at 5000 ppm. TCE was also cytotoxic in rats, causing a significant concentration-related decrease in the ratio of PCEs/normochromatic erythrocytes. This study indicates that there may be species-specific cytogenetic effects attributed to TCE inhalation exposure. In follow-up studies, CD rats were exposed for 6 h/day over 4 consecutive days to either 0, 5, 50 or 500 ppm TCE. No statistically significant concentration-related increases in cytogenetic damage were observed. While the MN frequencies in the 4-day study were comparable to those at the equivalent concentrations in the 1-day study, they were not significantly elevated due to an unusually high MN frequency in the controls. A subsequent replication of the 1-day 5000 ppm TCE exposure with rats again showed a highly significant increase in MN frequencies compared to concurrent controls. PMID:7519326

Kligerman, A D; Bryant, M F; Doerr, C L; Erexson, G L; Evansky, P A; Kwanyuen, P; McGee, J K

1994-08-01

64

A rodent model for the study of invariant visual object recognition  

PubMed Central

The human visual system is able to recognize objects despite tremendous variation in their appearance on the retina resulting from variation in view, size, lighting, etc. This ability—known as “invariant” object recognition—is central to visual perception, yet its computational underpinnings are poorly understood. Traditionally, nonhuman primates have been the animal model-of-choice for investigating the neuronal substrates of invariant recognition, because their visual systems closely mirror our own. Meanwhile, simpler and more accessible animal models such as rodents have been largely overlooked as possible models of higher-level visual functions, because their brains are often assumed to lack advanced visual processing machinery. As a result, little is known about rodents' ability to process complex visual stimuli in the face of real-world image variation. In the present work, we show that rats possess more advanced visual abilities than previously appreciated. Specifically, we trained pigmented rats to perform a visual task that required them to recognize objects despite substantial variation in their appearance, due to changes in size, view, and lighting. Critically, rats were able to spontaneously generalize to previously unseen transformations of learned objects. These results provide the first systematic evidence for invariant object recognition in rats and argue for an increased focus on rodents as models for studying high-level visual processing.

Zoccolan, Davide; Oertelt, Nadja; DiCarlo, James J.; Cox, David D.

2009-01-01

65

Laboratory and Space Plasma Studies.  

National Technical Information Service (NTIS)

The work performed by Science Applications International Corporation (SAIC) on this contract, 'Laboratory and Space Plasma Studies,' Contract Number N00014-93-C-2178, SAIC Project Number 01-0157-03-6984, encompasses a wide range of topics in experimental,...

E. Hyman Y. Aglitsky O. Barr A. Bar-Shalom C. L. Chang

1996-01-01

66

Rodent repellency  

USGS Publications Warehouse

In the course of studies involving more than 2,500 chemical repellents, it has been found that certain groups of- compounds containing nitrogen or sulfur are repellent to rats under the , test conditions and it appears probable that some of these compounds might be used for the protection of packaged goods against rodent attacks. Additional tests to determine optimum methods of application will be necessary before final evaluation of these compounds will be possible and extensive field trials will be required to establish the degree of protection which may be afforded by the use of these materials. Pending such final evaluation, it may be assumed that the results,to date offer a means of selecting the most promising types of'materials for further trial....On the basis of the test data, it appears that some amine derivative, such as a salt of some organic, acid, or a complex with trinitrobenzene or with a metallic salt of a dialkyl dithiocarbamic acid might offer promise of protection of packaging materials against rodent attacks....Protection might be obtained through the use of certain 'physical deterrents' such as plastics, waxes or drying oils.

DeWitt, J.B.; Welch, J.F.; Bellack, E.

1950-01-01

67

The role of fat emulsion therapy in a rodent model of propranolol toxicity: A preliminary study  

Microsoft Academic Search

Introduction  In animal models, lipid emulsion therapy has been shown to ameliorate toxicity from a number of lipid soluble agents. This\\u000a preliminary study addresses the hypothesis that pretreatment with lipid emulsion protects against propranolol toxicity in\\u000a rodents.\\u000a \\u000a \\u000a \\u000a Methods  Ten spontaneously ventilating Rattus norvegicus rats were pretreated with either lipid emulsion or 0.9% normal saline before\\u000a undergoing a constant infusion of propranolol until

Grant Cave; Martyn G. Harvey; Craig D. Castle

2006-01-01

68

A longitudinal study of Sin Nombre virus prevalence in rodents, southeastern Arizona.  

PubMed Central

We determined the prevalence of Sin Nombre virus antibodies in small mammals in southeastern Arizona. Of 1,234 rodents (from 13 species) captured each month from May through December 1995, only mice in the genus Peromyscus were seropositive. Antibody prevalence was 14.3% in 21 white-footed mice (P. leucopus), 13.3% in 98 brush mice (P. boylii), 0.8% in 118 cactus mice (P. eremicus), and 0% in 2 deer mice (P. maniculatus). Most antibody-positive mice were adult male Peromyscus captured close to one another early in the study. Population dynamics of brush mice suggest a correlation between population size and hantavirus-antibody prevalence.

Kuenzi, A. J.; Morrison, M. L.; Swann, D. E.; Hardy, P. C.; Downard, G. T.

1999-01-01

69

Network "Rodent-borne pathogens" in Germany: longitudinal studies on the geographical distribution and prevalence of hantavirus infections.  

PubMed

Hantavirus infections are known in Germany since the 1980s. While the overall antibody prevalence against hantaviruses in the general human population was estimated to be about 1-2%, an average of 100-200 clinical cases are recorded annually. In the years 2005 and 2007 in particular, a large increase of the number of human hantavirus infections in Germany was observed. The most affected regions were located in the federal states of Baden-Wuerttemberg, Bavaria, North Rhine Westphalia, and Lower Saxony. In contrast to the well-documented situation in humans, the knowledge of the geographical distribution and frequency of hantavirus infections in their rodent reservoirs as well as any changes thereof was very limited. Hence, the network "Rodent-borne pathogens" was established in Germany allowing synergistic investigations of the rodent population dynamics, the prevalence and evolution of hantaviruses and other rodent-associated pathogens as well as their underlying mechanisms in order to understand their impact on the frequency of human infections. A monitoring of hantaviruses in rodents from endemic regions (Baden-Wuerttemberg, Bavaria, North Rhine Westphalia, Lower Saxony) and regions with a low number of human cases (Mecklenburg Western-Pomerania, Brandenburg, Saxony, Saxony-Anhalt) was initiated. Within outbreak regions, a high prevalence of Puumala virus (PUUV) was detected in bank voles. Initial longitudinal studies in North Rhine Westphalia (city of Cologne), Bavaria (Lower Bavaria), and Lower Saxony (rural region close to Osnabrück) demonstrated a continuing presence of PUUV in the bank vole populations. These longitudinal studies will allow conclusions about the evolution of hantaviruses and other rodent-borne pathogens and changes in their distribution, which can be used for a risk assessment of human infections. This may become very important in order to evaluate changes in the epidemiology of rodent-borne pathogens in the light of expected global climate changes in the future. PMID:19030894

Ulrich, R G; Schmidt-Chanasit, J; Schlegel, M; Jacob, J; Pelz, H-J; Mertens, M; Wenk, M; Büchner, T; Masur, D; Sevke, K; Groschup, M H; Gerstengarbe, F-W; Pfeffer, M; Oehme, R; Wegener, W; Bemmann, M; Ohlmeyer, L; Wolf, R; Zoller, H; Koch, J; Brockmann, S; Heckel, G; Essbauer, S S

2008-11-23

70

The structure of rodent faunas associated with arenaviral infections  

PubMed Central

The biogeographical examination of rodent faunas associated with arenaviruses reveals two distinct patterns. Lymphocytic choriomeningitis (LCM) virus is associated primarily with a single murid species, Mus musculus, although it is also known to cause laboratory infections in other species. On the other hand, the arenaviruses from the Western hemisphere are associated exclusively with a large and diverse group of cricetid rodents. Studies to date, although limited, have not demonstrated their association with any other rodent groups, although in South America alone at least twelve other rodent families are known. Evidence at the present time indicates that Lassa virus is only associated with a common African rodent, Mastomys natalensis. From this limited evidence it is as yet difficult to determine whether Lassa virus will follow the pattern of the South American arenaviruses, most of which are known from several species of rodents, or that of LCM virus, which appears to be associated with only a single rodent species. In this paper, the history and structure of South American, Eurasian, and African rodent faunas are described.

Arata, A. A.; Gratz, N. G.

1975-01-01

71

Laboratory study of ballasted flocculation.  

PubMed

Ballasted flocculation is applied successfully in the water treatment industry, but the concept has not yet been subject to extended experimental studies. The use of a microsand and a polymer together to increase the weight of the flocs and the rate at which they settle is radically changing the coagulation flocculation-settling methodology. The objective of this research is to study ballasted flocculation in the laboratory by means of a modified jar-test procedure. The first tests, conducted using a statistical approach, enabled us to identify those parameters that have a significant influence on the quality of settled water. The principal treatment parameters considered in this study were the chemical dosage, the contact times in the different basins, the pH of coagulation and the dosage of microsand. The parameters used to evaluate the quality of the settled water, and hence treatment performances, were turbidity, UV absorbance, TOC and membrane filterability. The results showed that the coagulant dosage and the coagulation pH have a preponderant effect on the variability of the quality of the settled water. By contrast, filterability as measured by the laboratory filter tests, was found to be more sensitive to coagulant and microsand dosages. It was dependent on the ratio of microsand to polymer dosage, and improved when this ratio increased. PMID:11827335

Desjardins, Christian; Koudjonou, Boniface; Desjardins, Raymond

2002-02-01

72

Rodent repellent studies. IV. Preparation and properties of trinitrobenzene-aryl amine complexes  

USGS Publications Warehouse

Data are presented on methods of preparation, chemical arid physical characteristics, toxicity, and repellency to rodents of complexes of symmetrical trinitrohenzene with various aromatic amines: When applied in suitable carriers or incorporated in plastic .films, members of this series ofmaterials were shown to offer significant increases in time required by wild rodents to damage common packaging materials.

DeWitt, J.B.; Bellack, E.; Welch, J.F.

1953-01-01

73

A Review of the Methods of Studies on Infant Ultrasound Production and Maternal Retrieval in Small Rodents  

Microsoft Academic Search

Ultrasonic vocalizations or calls produced by young rodents have been associated with aspects of maternal behavior, in particular retrieving. We reviewed the methods of study used by investigators on each topic, focusing on intrinsic or subject variables and extrinsic or experimental variables. Intrinsic variables included the species studied, genotypes employed, number and sex composition of the litters, and the ages

Martin E. Hahn; Maria J. Lavooy

2005-01-01

74

Preliminary study on potential circulation of arenaviruses in the rodent population of Nakhon Pathom Province, Thailand and their medical importance in an evoluting environment.  

PubMed

Preliminary serological investigations were prefered to detect evidence of arenavirus infection in rodents. The study examined virus antibody in 367 rodents trapped in 6 different geographical areas of Nakhon Pathom Province, Thailand from February-March, 1998. The overall seroprevalence among rodents was 13.3%, mostly in Bandicota savilei (35.7%) and Rattus norvegicus (31.5%). Between ecology, behavior and sex of the rodents, seroprevalence was not significantly different (p>0.05), however the seroprevalence found among different geographical areas of Nakhon Pathom Province were significantly different (p<0.0001). PMID:11023066

Nitatpattana, N; Chauvancy, G; Jumronsawat, K; Poblap, T; Yoksan, S; Gonzalez, J P

2000-03-01

75

Ventilatory function assessment in safety pharmacology: Optimization of rodent studies using normocapnic or hypercapnic conditions  

SciTech Connect

Although the whole body plethysmography for unrestrained animals is the most widely used method to assess the respiratory risk of new drugs in safety pharmacology, non-appropriate experimental conditions may mask deleterious side effects of some substances. If stimulant or bronchodilatory effects can be easily evidenced in rodents under standard experimental conditions, i.e. normal air breathing and diurnal phase, drug-induced respiratory depression remains more difficult to detect. This study was aimed at comparing the responsiveness of Wistar rats, Duncan Hartley guinea-pigs or BALB/c mice to the respiratory properties of theophylline (50 or 100 mg/kg p.o.) or morphine (30 mg/kg i.p.) under varying conditions (100% air versus 5% CO{sub 2}-enriched air, light versus dark day phase), in order to select the most appropriate experimental conditions to each species for safety airway investigations. Our results showed that under normocapnia the ventilatory depressant effects of morphine can be easily evidenced in mice, slightly observed in guinea-pigs and not detected in rats in any day phase. Slight hypercapnic conditions enhanced the responsiveness of rats to morphine but not that of guinea-pigs and importantly they did not blunt the airway responsiveness of rats to the stimulation and bronchodilation evoked by theophylline, the most widely used reference agent in safety pharmacology studies. In conclusion, hypercapnic conditions associated with the non-invasive whole body plethysmography should be considered for optimizing the assessment of both the ventilatory depressant potential of morphine-like substances or the respiratory stimulant effects of new drugs in the rat, the most extensively used species in rodent safety and toxicological investigations.

Goineau, Sonia; Rompion, Sonia; Guillaume, Philippe [Porsolt and Partners Pharmacology, Z.A. des Suhards, 53940 Le Genest-Saint-Isle (France); Picard, Sandra, E-mail: spicard@porsolt.co [Porsolt and Partners Pharmacology, Z.A. des Suhards, 53940 Le Genest-Saint-Isle (France)

2010-09-15

76

A Reverse-Translational Approach to Bipolar Disorder: Rodent and human studies in the Behavioral Pattern Monitor  

PubMed Central

Mania is the defining feature of Bipolar Disorder (BD). There has been limited progress in understanding the neurobiological underpinnings of BD mania and developing novel therapeutics, in part due to a paucity of relevant animal models with translational potential. Hyperactivity is a cardinal symptom of mania, traditionally measured in humans using observer-rated scales. Multivariate assessment of unconditioned locomotor behavior using the rat Behavioral Pattern Monitor (BPM) developed in our laboratory has shown that hyperactivity includes complex multifaceted behaviors. The BPM has been used to demonstrate differential effects of drugs on locomotor activity and exploratory behavior in rats. Studies of genetically engineered mice in a mouse BPM have confirmed its utility as a cross-species tool. In a “reverse-translational” approach to this work, we developed the human BPM to characterize motor activity in BD patients. Increased activity, object interactions, and altered locomotor patterns provide multidimensional phenotypes to model in the rodent BPM. This unique approach to modeling BD provides an opportunity to identify the neurobiology underlying BD mania and test novel antimanic agents.

Young, Jared W.; Minassian, Arpi; Paulus, Martin P.; Geyer, Mark A.; Perry, William

2007-01-01

77

[Serologic studies of domestic cats for potential human pathogenic virus infections from wild rodents].  

PubMed

For several viral infections a reservoir in wild rodents has been demonstrated. Some of the agents are known or suspected to be pathogenic for humans. Because improvements in hygiene have reduced direct human contact with rodents, domestic cats could be acting as active transmitters of these viruses from rodents to man. We selected 4 such pathogens--ortho- and parapox-, hanta- and encephalomyocarditis viruses--which, in different ways, may lead to serious human illness: Ortho- and parapoxvirus infections may cause localized pox lesions following direct skin contact. In general, the lesions heal without complications; in immunosuppressed or -deficient individuals, however, infection may generalize and take a dramatic course. Hantaviruses exist in various serotypes with different pathogenicity for human beings, varying from asymptomatic infection to highly fatal disease. In central and northern Europe the Puumala serotype is predominant causing influenza-like symptoms and renal dysfunction. Human infections arise from inhalation of aerosolized excreta of persistently infected rodents. Infections of man associated with encephalomyocarditis virus were demonstrated sporadically in cases of encephalitis and meningitis. In the present study, we investigated in 200 feline serum samples the prevalence of antibodies to ortho- and parapox-, hanta- and encephalomyocarditis virus. All serum samples were from cats that had been allowed to roam outside and to hunt. They were submitted from all parts of Austria for routine diagnosis in 1993. Four per cent of cats showed antibodies to orthopoxviruses with haemagglutination inhibition (HI) titres of 16-512; because of extensive cross-reactivity, positive samples reacted with all investigated orthopoxviruses (a feline orthopoxvirus recently isolated in Vienna, the reference strain of cowpox virus, Brighton, and vaccinia virus, strain IHD), only varying in titre. The specificity of the results was confirmed by virus neutralisation (VN) test, in which the same sera showed titres of 4-32. These data imply that, at least in Austria, unrecognized or subclinical orthopoxvirus infection in cats is more common than previously thought. In contrast to orthopoxviruses, all serum samples proved negative to parapoxvirus (parapoxvirus bovis 1) in VN test. In the same 200 samples, a seroprevalence of 5% was found to hantavirus (immunofluorescence antibody assay), indicating that domestic cats are susceptible to this virus and that infection is not uncommon in cat populations. Because higher titres were obtained against the Puumala serotype compared to the more pathogenic serotype Hantaan, it is most likely that the cats had experienced Puumala infections. Using HI test, antibodies to encephalomyocarditis virus (EMCV) were demonstrated in only 1.5% of the feline serum samples; although the antibody titres were low (16 and 32, respectively) we consider them specific, because these sera proved positive in VN test as well. Nevertheless, EMCV infection in domestic cats seems to be of low importance. The serological results presented in this paper, together with virological and epidemiological data, indicate that the domestic cat plays an important role only in the transmission of orthopoxviruses to human beings, but not in the case of parapox-, hanta-, and encephalomyocarditis virus. PMID:9409901

Nowotny, N

1996-05-01

78

CYTOKINE REGULATION OF HOST DEFENSE AGAINST PARASITIC GASTROINTESTINAL NEMATODES:Lessons from Studies with Rodent Models*1  

Microsoft Academic Search

Studies with rodents infected with Trichinella spiralis, Heligmosomoides poly- gyrus, Nippostrongylus brasiliensis, and Trichuris muris have provided consid- erable information about immune mechanisms that protect against parasitic gas- trointestinal nematodes. Four generalizations can be made: 1. CD4 C T cells are critical for host protection; 2. IL-12 and IFN- inhibit protective immunity; 3. IL-4 can: (a) be required for host

Fred D. Finkelman; Terez Shea-Donohue; Jon Goldhill; Carolyn A. Sullivan; Suzanne C. Morris; Kathleen B. Madden; William C. Gause

1997-01-01

79

A laboratory study of ploughing  

NASA Astrophysics Data System (ADS)

A new laboratory device is used to investigate the resistance to clast ploughing at the base of glaciers. In experiments in which a ploughing tip is dragged at different velocities and effective normal stresses through water-saturated sediment from Unteraargletscher, Switzerland, pore pressures above and below the hydrostatic level develop around the tip. The absolute magnitude of these non-hydrostatic pore pressures increases with the ploughing velocity but remains small compared to the sediment yield strength, so that the pore pressures do not significantly weaken the sediment. The shear stress on the tip is independent of the velocity but scales with the applied effective normal stress, in agreement with a Coulomb-plastic behavior of the sediment. The results indicate that, depending upon position close to the object, both sediment compaction and dilation can influence the pore-pressure distribution and thus the sediment yield strength. Comparison with other studies of clast ploughing suggests that the significance of sediment weakening in front of ploughing clasts may depend on the relative magnitudes of the non-hydrostatic pore pressures. Therefore, depending on the dominant pore-pressure response of the deforming sediment, clast ploughing may have the potential to either trigger ice-flow instabilities or stabilize glacier motion.

Rousselot, Marie; Fischer, Urs H.

80

An Experimental Approach for Selecting Appropriate Rodent Diets for Research Studies on Metabolic Disorders  

PubMed Central

Diverse high energy diets have been utilized to precipitate obesity and related metabolic disorders in rodent models, though the dietary intervention has not absolutely been standardized. The present study established usage of a customized semipurified normal control diet (NCD) and high fat diet (HFD), for research studies on diet-induced metabolic disorders in albino rats. Male Wistar rats were fed with normal pellet diet (NPD) or customized NCDs I, II, III or HFDs I, II, III for 12 weeks and parameters, namely, body weight, visceral adiposity, serum triglycerides, cholesterol, and glucose were evaluated to select an appropriate NCD and HFD. The selected HFD was further evaluated for induction of fatty liver, whilst type 2 diabetes (T2D) induction was confirmed in HFD and streptozotocin (STZ) induced diabetes model in Wistar rats. Amongst different diets tested, NCD-I and HFD-I were selected, since NCD-I exhibited close resemblance to NPD, whereas HFD-I induced metabolic alterations, particularly obesity and dyslipidemia consistently. Moreover, HFD-I elevated terminal hepatic lipids, while HFD-I/STZ treatment augmented insulin resistance index and serum glucose levels significantly indicating effective induction of fatty liver and T2D, respectively. Therefore, customized semipurified NCD-I and HFD-I can be recommended for research studies on diet-induced metabolic disorders in albino Wistar rats.

Sasidharan, Suja Rani; Joseph, Joshua Allan; Anandakumar, Senthilkumar; Venkatesan, Vijayabalaji; Ariyattu Madhavan, Chandrasekharan Nair; Agarwal, Amit

2013-01-01

81

CAVEATS REGARDING THE USE OF THE LABORATORY RATS AS A MODEL FOR ACUTE TOXICOLOGICAL STUDIES: MODULATION OF THE TOXIC RESPONSE VIA PHYSIOLOGICAL AND BEHAVIORAL MECHANISMS  

EPA Science Inventory

The rodent, specifically the inbred laboratory rat, is the primary experimental animal used in toxicology testing. Despite its popularity, recent studies from our laboratory and others raise a number of questions concerning the rat's appropriateness as an animal model for toxicol...

82

Heart rate variability in rodents: uses and caveats in toxicological studies.  

PubMed

Heart rate variability (HRV) is a measure of cardiac pacing dynamics that has recently garnered a great deal of interest in environmental health studies. While the use of these measures has become popular, much uncertainty remains in the interpretation of results, both in terms of human and animal research. In humans, HRV endpoints, specifically chronic alterations in baseline HRV patterns, have been reasonably well characterized as prognostic indicators of adverse outcomes for a variety of diseases. However, such information is lacking for reversible HRV changes that may be induced by short-term exposures to environmental toxicants. Furthermore, there are minimal substantive data, either acute or chronic, regarding the pathological interpretation or prognostic value of toxicant-induced changes in HRV in rodents. The present report summarizes the physiological and clinical aspects of HRV, the methodological processes for obtaining these endpoints, and previous human and animal studies in the field of environmental health. Furthermore, we include a discussion of important caveats and recommendations for the interpretation of HRV data in animal research. PMID:17646680

Rowan, William H; Campen, Matthew J; Wichers, Lindsay B; Watkinson, William P

2007-01-01

83

Laboratory Study of Till Rheology  

NASA Astrophysics Data System (ADS)

Recent studies show that small-amplitude stress changes can trigger ice sheet motion and subglacial seismicity. Deformation in the subglacial region plays a key role in determining slip behavior, including creep, transient slip, stick-slip motion, and seismicity. However, progress in understanding these phenomena is limited by uncertainty in the rheology and frictional properties of glacial till. We report on detailed laboratory experiments to measure the creep and frictional constitutive properties of till sampled from the Matanuska Glacier, Alaska and Caesar Till from the Scioto Lobe of the Laurentide Ice Sheet, sampled in central Ohio. Experiments were conducted in a servo-controlled, double direct shear apparatus with air dried samples at a normal stresses ranging from 50 kPa to 5 MPa. Till was sheared in a three-block arrangement in which two layers are sandwiched between a central forcing block and two stationary blocks. We studied the effect of saturation, initial deformation fabric, stress history, and the boundary conditions of loading. The nominal frictional contact area is 100 cm2 and remains constant during shear. The layer thickness is 1 cm prior to shear. All blocks are grooved perpendicular to the shear direction to ensure that deformation occurs within the layer. The Matanuska till has grains ranging from 6.3 mm to finer than .063 mm with a mean of 2.67 mm whereas the Caesar till has a smaller mean grain size of 0.60 mm, but lacks silt and clay sized particles. We conducted both constant strain rate and constant stress tests. Constant shear stress experiments were employed to study frictional creep. In these tests, stress steps were conducted at 2 % and 5 % steps of the shear strength with strain rate calculated at 20 and 40 minute intervals after the stress steps. Strain rate was calculated by taking a linear fit of strain versus time over two minutes. The stress exponent, n was then calculated from the equation d?/dt = b?n. Where ? is strain, ? shear stress, and b is a constant. Under these conditions till was found to deform plasticly with a stress exponent that ranged from n=10 to n=18. Experiments taken directly to constant load conditions without an initial displacement exhibited a lower strain rate and smaller stress exponent than experiments, which first deformed the sample to failure with an initial 10 mm displacement. Constant strain rate tests were used to study rate/state frictional rheology using perturbations in slip rate of 1 to 300 ?m/s, imposed during steady sliding. Results of velocity stepping experiments showed velocity strengthening frictional behavior for both Matanuska and Caesar Till. The degree of velocity strengthening is less for the Caesar till compared to the Matanuska, and both tills exhibit lesser velocity strengthening for saturated compared to dry tests. Coulomb-Mohr failure envelopes for saturated conditions indicate that the Matanuska and Caesar tills have angles of internal friction and cohesion of 31.5° and 9.5 kPa, and 28.0° and near zero, respectively.

Rathbun, A. P.; Marone, C. J.; Anandakrishnan, S.; Alley, R. B.

2005-12-01

84

Monkeypox detection in rodents using real-time 3'minor groove binder Taqman assays on the Roche LightCycler, Laboratory Investigation 84:1200 - 1208.  

National Technical Information Service (NTIS)

During the summer of 2003, an outbreak of human monkeypox occurred in the Midwest region of the United States. In all, 52 rodents suspected of being infected with monkeypox virus were collected from an exotic pet dealer and from private homes. The rodents...

D. A. Kulesh B. M. Loveless D. Norwood J. Garrison C. A. Whitehouse

2004-01-01

85

Tactile and non-tactile sensory paradigms for fMRI and neurophysiologic studies in rodents  

PubMed Central

Functional magnetic resonance imaging (fMRI) has become a popular functional imaging tool for human studies. Future diagnostic use of fMRI depends, however, on a suitable neurophysiologic interpretation of the blood oxygenation level dependent (BOLD) signal change. This particular goal is best achieved in animal models primarily due to the invasive nature of other methods used and/or pharmacological agents applied to probe different nuances of neuronal (and glial) activity coupled to the BOLD signal change. In the last decade, we have directed our efforts towards the development of stimulation protocols for a variety of modalities in rodents with fMRI. Perception of the natural world relies on the formation of multi-dimensional representation of stimuli impinging on the different sensory systems, leading to the hypothesis that a sensory stimulus may have very different neurophysiologic outcome(s) when paired with a near simultaneous event in another modality. Before approaching this level of complexity, reliable measures must be obtained of the relatively small changes in the BOLD signal and other neurophysiologic markers (electrical, blood flow) induced by different peripheral stimuli. Here we describe different tactile (i.e., forepaw, whisker) and non-tactile (i.e., olfactory, visual) sensory paradigms applied to the anesthetized rat. The main focus is on development and validation of methods for reproducible stimulation of each sensory modality applied independently or in conjunction with one another, both inside and outside the magnet. We discuss similarities and/or differences across the sensory systems as well as advantages they may have for studying essential neuroscientific questions. We envisage that the different sensory paradigms described here may be applied directly to studies of multi-sensory interactions in anesthetized rats, en route to a rudimentary understanding of the awake functioning brain where various sensory cues presumably interrelate.

Sanganahalli, Basavaraju G.; Bailey, Christopher J.; Herman, Peter; Hyder, Fahmeed

2013-01-01

86

Introduction to Rodent Cardiac Imaging  

Microsoft Academic Search

Imaging is a noninvasive complement to traditional meth- ods (such as histology) in rodent cardiac studies. Assess- ments of structure and function are possible with ultrasound, microcomputed tomography (microCT), and magnetic reso- nance (MR) imaging. Cardiac imaging in the rodent poses a challenge because of the size of the animal and its rapid heart rate. Each aspect in the process

Kennita Johnson

2008-01-01

87

Rodent-repellent studies. I. Method for the evaluation of chemical repellents  

USGS Publications Warehouse

A biological assay procedure and a method for the numerical expression of results have been devised for the determination of the repellency to rodents of different chemical compounds. The procedure is based upon the degree of acceptability of foods containing the candidate repellents,. and has been shown. to offer a rapid, reliable measure of repellent activIty.

Bellack, E.; DeWitt, J.B.

1949-01-01

88

Linking human behavior to environmental effects using a case study of urban rodent control  

EPA Science Inventory

Pest control is common practice in many land use activities worldwide. Although often inadvertent, pest control can affect non-target species, sometimes fatally. Using social survey data about residential rodent control behavior in two areas in California, we applied a framewor...

89

The use of cystometry in small rodents: a study of bladder chemosensation.  

PubMed

The lower urinary tract (LUT) functions as a dynamic reservoir that is able to store urine and to efficiently expel it at a convenient time. While storing urine, however, the bladder is exposed for prolonged periods to waste products. By acting as a tight barrier, the epithelial lining of the LUT, the urothelium, avoids re-absorption of harmful substances. Moreover, noxious chemicals stimulate the bladder's nociceptive innervation and initiate voiding contractions that expel the bladder's contents. Interestingly, the bladder's sensitivity to noxious chemicals has been used successfully in clinical practice, by intravesically infusing the TRPV1 agonist capsaicin to treat neurogenic bladder overactivity. This underscores the advantage of viewing the bladder as a chemosensory organ and prompts for further clinical research. However, ethical issues severely limit the possibilities to perform, in human subjects, the invasive measurements that are necessary to unravel the molecular bases of LUT clinical pharmacology. A way to overcome this limitation is the use of several animal models. Here we describe the implementation of cystometry in mice and rats, a technique that allows measuring the intravesical pressure in conditions of controlled bladder perfusion. After laparotomy, a catheter is implanted in the bladder dome and tunneled subcutaneously to the interscapular region. Then the bladder can be filled at a controlled rate, while the urethra is left free for micturition. During the repetitive cycles of filling and voiding, intravesical pressure can be measured via the implanted catheter. As such, the pressure changes can be quantified and analyzed. Moreover, simultaneous measurement of the voided volume allows distinguishing voiding contractions from non-voiding contractions. Importantly, due to the differences in micturition control between rodents and humans, cystometric measurements in these animals have only limited translational value. Nevertheless, they are quite instrumental in the study of bladder pathophysiology and pharmacology in experimental pre-clinical settings. Recent research using this technique has revealed the key role of novel molecular players in the mechano- and chemo-sensory properties of the bladder. PMID:22929055

Uvin, Pieter; Everaerts, Wouter; Pinto, Silvia; Alpízar, Yeranddy A; Boudes, Mathieu; Gevaert, Thomas; Voets, Thomas; Nilius, Bernd; Talavera, Karel; De Ridder, Dirk

2012-08-21

90

Towards constructivist laboratory education: Case study for process control laboratory  

Microsoft Academic Search

Laboratory education is an integrated part of engineering and science degrees. Many research papers refer to poor constructivist learning during the laboratory sessions, indicating the need for reforming the laboratory education in a way that facilitates constructivist learning as well as conceptual understanding. In this paper we present a model of conducting laboratories, based on the well known Kolbpsilas experiential

Mahmoud Abdulwahed; Zoltan K Nagy

2008-01-01

91

Laboratory study of ballasted flocculation  

Microsoft Academic Search

Ballasted flocculation is applied successfully in the water treatment industry, but the concept has not yet been subject to extended experimental studies. The use of a microsand and a polymer together to increase the weight of the flocs and the rate at which they settle is radically changing the coagulation–flocculation-settling methodology. The objective of this research is to study ballasted

Christian Desjardins; Boniface Koudjonou; Raymond Desjardins

2002-01-01

92

Issues in the design and interpretation of chronic toxicity and carcinogenicity studies in rodents: approaches to dose selection.  

PubMed

For more than three decades chronic studies in rodents have been the benchmark for assessing the potential long-term toxicity, and particularly the carcinogenicity, of chemicals. With doses typically administered for about 2 years (18 months to lifetime), the rodent bioassay has been an integral component of testing protocols for food additives, pesticides, pharmaceuticals, industrial chemicals, and all manner of byproducts and environmental contaminants. Over time, the data from these studies have been used to address an increasing diversity of questions related to the assessment of human health risks, adding complexity to study design and interpretation. An earlier ILSI RSI working group developed a set of principles for the selection of doses for chronic rodent studies (ILSI, 1997). The present report builds on that work, examining some of the issues that arise and offering new perspectives and approaches for putting the principles into practice. Dose selection is considered both from the prospective viewpoint of the choosing of dose levels for a study and from the retrospective interpretation of study results in light of the doses used. A main theme of this report is that the purposes and objectives of chronic rodent studies vary and should be clearly defined in advance. Dose placement, then, should be optimized to achieve study objectives. For practical reasons, most chronic studies today must be designed to address multiple objectives, often requiring trade-offs and innovative approaches in study design. A systematic approach to dose selection should begin with recognition that the design of chronic studies occurs in the context of a careful assessment of the accumulated scientific information on the test substance, the relevant risk management questions, priorities and mandates, and the practical limitations and constraints on available resources. A stepwise process is described. The aim is to increase insofar as possible the utility of an expensive and time-consuming experiment. The kinds of data that are most commonly needed for dose selection and for understanding the dose-related results of chronic rodent studies, particularly carcinogenicity studies, are discussed as "design/interpretation factors." They comprise both the inherent characteristics of the test substance and indicators of biological damage, perturbation or stress among the experimental animals. They may be primary toxicity endpoints, predictors or indicators of appropriate dose selection, or indicators of conditions to be avoided in dose selection. The application and interpretation of design/interpretation factors is conditioned by the study objectives-what is considered desirable will depend on the strategy for choice of doses that is being followed. The challenge is to select doses that accommodate all of the issues raised by the relevant design/interpretation factors. Three case studies are presented here that illustrate the interplay between study objectives and the design and selection of doses for chronic rodent studies. These examples also highlight issues associated with multiple plausible modes of action, multiple pathways for biotransformation of the chemical, extraneous high-dose effects, the use of modeling in dose selection, and the implications of human exposure levels. Finally, looking to the future, the report explores seven potential paradigm shifts for risk assessment that will significantly impact the design and interpretation of toxicity and carcinogenicity studies. PMID:17957539

Rhomberg, Lorenz R; Baetcke, Karl; Blancato, Jerry; Bus, James; Cohen, Samuel; Conolly, Rory; Dixit, Rakesh; Doe, John; Ekelman, Karen; Fenner-Crisp, Penny; Harvey, Paul; Hattis, Dale; Jacobs, Abigail; Jacobson-Kram, David; Lewandowski, Tom; Liteplo, Robert; Pelkonen, Olavi; Rice, Jerry; Somers, Diana; Turturro, Angelo; West, Webster; Olin, Stephen

2007-01-01

93

Identification and study of a poxvirus isolated from wild rodents in Turkmenia.  

PubMed

A new poxvirus was isolated in 1974 from the kidney of a wild big gerbil (Rhombomys opimus) caught in Turkmenia, where these gerbils are wide-spread. The virus resembles cowpox virus and is markedly different from the virus of infectious ectromelia, the best-known poxvirus of rodents. The new virus is apparently identical to other poxvirus isolates made from white rats and Felidae in the Moscow Zoo. Experimental inoculation of the natural hosts--big gerbils and yellow susliks (Citellus fulvus)--produced a severe infection with a high mortality rate. Trnasmission of virus to uninoculated cage mates was shown to occur. Virus persisted in convalescent animals and was present in urine 3 weeks after inoculation and in kidney and testis for at least 5 weeks after inoculation. The role of rodents as natural hosts of poxviruses is discussed. PMID:204271

Marennikova, S S; Ladnyj, I D; Ogorodinikova, Z I; Shelukhina, E M; Maltseva, N N

1978-01-01

94

Meal-feeding rodents and toxicology research.  

PubMed

Most laboratory rodents used for toxicology studies are fed ad libitum, with unlimited access to food. As a result, ad libitum-fed rodents tend to overeat. Research demonstrates that ad libitum-fed rodents are physiologically and metabolically different from rodents fed controlled amounts of food at scheduled times (meal-fed). Ad libitum-fed rodents can develop hypertriglyceridemia, hypercholesterolemia, diet-induced obesity, nephropathy, cardiomyopathy, and pituitary, pancreatic, adrenal, and thyroid tumors, conditions likely to affect the results of toxicology research studies. In contrast, meal-feeding synchronizes biological rhythms and leads to a longer life span, lower body weight, lower body temperature, hypertrophy of the small intestine, and synchronization of hepatic and digestive enzymes. The circadian rhythms present in nearly all living organisms are entrained by light intensity and food intake, and peripheral clocks in all organs of the body, especially the GI tract and liver, are particularly sensitive to food intake. Feeding schedule has been demonstrated to alter the toxicity and metabolism of drugs including sodium valproate, chloral hydrate, acetaminophen, gentamicin, and methotrexate. Feeding schedule alters the expression of genes that code for Phase I, II, and III proteins, thereby altering the rate and amplitude of drug disposition. Rhythms of plasma insulin and glucagon that fluctuate with food ingestion are also altered by feeding schedule; ad libitum feeding promotes hyperinsulinemia which is a precursor for developing diabetes. The emerging field of chronopharmacology, the interaction of biological rhythms and drugs, will lead to optimizing the design and delivery of drugs in a manner that matches biological rhythms, but it is wise for toxicology researchers to consider feeding schedule when designing these experiments. It has been 10 years since the Society for Toxicologic Pathology voiced its position that feeding schedule is an important variable that should be controlled in toxicology experiments, and research continues to underscore this position. PMID:22642213

Carey, Gale B; Merrill, Lisa C

2012-06-13

95

Effects of Laboratory Housing on Exploratory Behaviour, Novelty Discrimination and Spatial Reference Memory in a Subterranean, Solitary Rodent, the Cape Mole-Rat (Georychus capensis).  

PubMed

A large number of laboratory and field based studies are being carried out on mole-rats, both in our research group and others. Several studies have highlighted the development of adverse behaviours in laboratory animals and have emphasised the importance of enrichment for captive animals. Hence we were interested in evaluating how laboratory housing would affect behavioural performance in mole-rats. We investigated exploratory behaviour, the ability to discriminate between novel and familiar environments and reference memory in the solitary Cape mole-rat (Georychuscapensis). Our data showed that both wild and captive animals readily explore open spaces and tunnels. Wild animals were however more active than their captive counterparts. In the Y maze two trial discrimination task, wild animals failed to discriminate between novel and familiar environments, while laboratory housed mole-rats showed preferential spatial discrimination in terms of the length of time spent in the novel arm. The performance of the laboratory and wild animals were similar when tested for reference memory in the Y maze, both groups showed a significant improvement compared to the first day, from the 3rd day onwards. Wild animals made more mistakes whereas laboratory animals were slower in completing the task. The difference in performance between wild and laboratory animals in the Y-maze may be as a result of the lower activity of the laboratory animals. Laboratory maintained Cape mole-rats show classic behaviours resulting from a lack of stimulation such as reduced activity and increased aggression. However, they do display an improved novelty discrimination compared to the wild animals. Slower locomotion rate of the laboratory animals may increase the integration time of stimuli, hence result in a more thorough inspection of the surroundings. Unlike the captive animals, wild animals show flexibility in their responses to unpredictable events, which is an important requirement under natural living conditions. PMID:24040422

Oosthuizen, Maria Kathleen; Scheibler, Anne-Gita; Charles Bennett, Nigel; Amrein, Irmgard

2013-09-11

96

A Guide to Research Rodent Housing  

Microsoft Academic Search

BACKGROUND Laboratory rodents have been used in the United States as research animals since the late 1800s. In the past, housing of rodents used for research was designed primarily to prevent escape, to provide easy access to the animals by researchers, to allow the animals ready access to food and water, and to allow efficient dirty bedding removal and cage

William J. White

97

Laboratory studies of astrophysical molecules  

Microsoft Academic Search

There is growing evidence that the molecules necessary for the evolution of life on earth arrived from the interstellar medium. The study of these molecules is therefore of great current interest. Two major types of signals from interstellar space, so-called unidentified interstellar infrared emission bands and the diffuse interstellar absorption bands, have intrigued and puzzled astrochemists for decades. This work

Haiyan Wang

2005-01-01

98

The harderian gland of desert rodents: a histological and ultrastructural study.  

PubMed Central

This study describes the structure of the harderian gland in desert rodents: 3 Gerbillidae species (Gerbillus gerbillus, Meriones crassus, Psammomys obesus) and 1 Ctenodactylidae species (Ctenodactylus vali). In all these species the gland consists of tubules lined by a single layer of epithelial cells and possesses myoepithelial cells within their basal laminae. The gland contains porphyrin which is stored as solid intraluminal deposits. The glandular epithelium presents a single cell type (type I) in Psammomys obesus, 2 cell types (I and II) in Ctenodactylus vali and 3 (I, II and III) in Gerbillus gerbillus and Meriones crassus. The type I and II cells are columnar. They are characterised by many lipid vacuoles and a well developed vesicle-like structure of smooth endoplasmic reticulum. In Gerbillus gerbillus and Meriones crassus the type I cells can be distinguished from type II cells by cytoplasmic clefts approximately 1 micron in length. In Ctenodactylus vali type I cells are characterised by cytoplasmic rod-shaped crystalloid structures approximately 0.5 microns in length which are frequently observed in the mitochondrial matrix. These structures are also present in the sole cell type of Psammomys obesus. Most of the secretory lipid vacuoles of the type I cell contain an electron-dense material, possibly porphyrin, which presents different appearances according to species: it is lamellar in Gerbillus gerbillus, trilamellar in Meriones crassus, and amorphous in Psammomys obesus and Ctenodactylus vali. Secretory lipid vacuoles are released primarily by exocytosis, but holocrine and apocrine secretion is also observed. The type III cells are pyramidal. This cell type is characterised by the presence of an extraordinarily well developed granular endoplasmic reticulum, organised in concentric lamellae in Gerbillus gerbillus, and very numerous mitochondria. Epithelial cells are frequently binucleate. The single excretory duct contains both mucous and serous cells. Mast cells, plasma cells, macrophages, fenestrated capillaries and unmyelinated nerve endings with clear or dense-cored vesicles are present in the connective tissue. Melanocytes are very numerous in the interstices of the Gerbillidae harderian gland. The gland is surrounded by a collagenous capsule and an outer layer of endothelial cells derived from the orbital venous sinus. Images Fig. 1 Fig. 2 Fig. 3 Fig. 4 Fig. 5 Fig. 6 Fig. 7 Fig. 8 Fig. 9 Fig. 10 Fig. 11 Fig. 12 Fig. 13 Fig. 14 Fig. 15 Fig. 16 Fig. 17 Fig. 18 Fig. 19 Fig. 20 Fig. 21 Fig. 22 Fig. 23 Fig. 24 Fig. 25 Fig. 26 Fig. 27 Fig. 28 Fig. 29 Fig. 30

Djeridane, Y

1992-01-01

99

Colonisation and shedding of Lawsonia intracellularis in experimentally inoculated rodents and in wild rodents on pig farms.  

PubMed

Lawsonia intracellularis is an intracellular bacterium causing proliferative enteropathy in various animal species, and is considered an economically important pathogen of pigs. Rats and mice have been implicated as external vectors for a wide range of pig pathogens, including L. intracellularis. Previous studies have demonstrated L. intracellularis infection and proliferative enteropathy in rodents, but did not show the duration of shedding or the number of L. intracellularis shed by infected rodents, and therefore the infection risk that rodents pose to pigs. In this study, the number of L. intracellularis shed in the faeces and intestinal mucosa of wild rats trapped on pig farms was determined by a quantitative real time polymerase chain reaction assay. The prevalence of L. intracellularis in wild rats trapped on pig farms with endemic proliferative enteropathy (PE) was very high (? 70.6%), and large numbers of L. intracellularis were shed (10(10)/g of faeces) in a small proportion of wild rats. The duration of colonisation in laboratory rats and mice challenged with porcine isolates of L. intracellularis was also shown. Faecal shedding of L. intracellularis persisted for 14-21 days in rats and mice that were mildly affected with histological lesions of PE. The humoral immune response to L. intracellularis persisted for 40 days in both species. This study demonstrates that rodents may be an important reservoir of L. intracellularis on piggeries, and hence rodent control is important in disease eradication programs on pig farms. PMID:21349664

Collins, A M; Fell, S; Pearson, H; Toribio, J-A

2011-02-01

100

Rodent Empathy and Affective Neuroscience  

PubMed Central

In the past few years, several experimental studies have suggested that empathy occurs in the social lives of rodents. This indicates that rodent behavioral models can be developed in an attempt to elucidate the mechanistic substrates of empathy at levels that have heretofore been unavailable. For example, the finding that mice from certain inbred strains express behavioral and physiological responses to conspecific distress, while others do not, underscores that the genetic underpinnings of empathy are specifiable and that in the future they could be harnessed to develop new therapies for human psychosocial impairments. However, the advent of rodent models of empathy is met at the outset with a number of theoretical and semantic problems that are similar to those previously confronted by studies of empathy in humans. The distinct underlying components of empathy must be differentiated from one another and from lay usage of the term. The primary goal of this paper is to review a set of seminal studies that are directly relevant to developing a concept of empathy in rodents. We first consider some of the psychological phenomena that have been associated with empathy, and within this context, we consider the component processes, or endophenotypes of rodent empathy. We then review a series of recent experimental studies that demonstrate the capability of rodents to detect and respond to the affective state of their social partners. We focus primarily on experiments that examine how rodents share affective experiences of fear, but we also highlight how similar types of experimental paradigms can be utilized to evaluate the possibility that rodents share positive affective experiences. Taken together, these studies were inspired by Jaak Panksepp’s theory that all mammals are capable of felt affective experiences.

Panksepp, Jules B.; Lahvis, Garet P.

2011-01-01

101

Rodent models of glaucoma  

PubMed Central

Glaucoma is a progressive, age-related optic neuropathy and a leading cause of irreversible blindness in the world. Animal models of glaucoma are essential to our continued efforts of elucidating the natural course of the disease and to developing therapeutic interventions to halt or reverse the progression of the condition. Over the past 10–15 years, rodents have become a popular model organism in which to study glaucoma, because of their high degree of availability, relatively low cost, short life-span, and amenability to experimental and genetic manipulation. In this review, we examine the numerous in vivo and in vitro rodent models of glaucoma, discuss the methods used to generate them, summarize some of the major findings obtained in these models, and identify individual strengths and weaknesses for the various systems.

Johnson, Thomas V.; Tomarev, Stanislav I.

2010-01-01

102

Drillability Studies-Laboratory Percussive Drilling.  

National Technical Information Service (NTIS)

Laboratory drillability studies are reported on nine rock types using two mining-type percussive drills. Percussive-bit action was simulated by dropping a known weight on a rock sample to obtain a coefficient of rock strength for each rock drilled. Coeffi...

J. Paone D. Madson W. E. Bruce

1969-01-01

103

Intravital two-photon microscopy for studying the uptake and trafficking of fluorescently conjugated molecules in live rodents  

PubMed Central

Here we describe an experimental system based on intravital two-photon microscopy for studying endocytosis in live animals. The rodent submandibular glands were chosen as model organs since they can be exposed easily, imaged without compromising their function and, furthermore, they are amenable to pharmacological and genetic manipulations. We show that the fibroblasts within the stroma of the glands readily internalize systemically injected molecules such as fluorescently conjugated dextran and bovine serum albumin, providing a robust model to study endocytosis. We dynamically image the trafficking of these probes from the early endosomes to the late endosomes and lysosomes while also visualizing homotypic fusion events between early endosomes. Finally, we demonstrate that pharmacological agents can be delivered specifically to the submandibular salivary glands thus providing a powerful tool to study the molecular machinery regulating endocytosis in a physiological context.

Masedunskas, Andrius; Weigert, Roberto

2009-01-01

104

Laboratory microfusion capability study. Phase II report  

SciTech Connect

The purpose of this study is to elucidate the issues involved in developing a Laboratory Microfusion Capability (LMC) which is the major objective of the Inertial Confinement Fusion (ICF) program within the purview of the Department of Energy`s Defense Programs. The study was initiated to support a number of DOE management needs: to provide insight for the evolution of the ICF program; to afford guidance to the ICF laboratories in planning their research and development programs; to inform Congress and others of the details and implications of the LMC; to identify criteria for selection of a concept for the Laboratory Microfusion Facility and to develop a coordinated plan for the realization of an LMC. As originally proposed, the LMC study was divided into two phases. The first phase identifies the purpose and potential utility of the LMC, the regime of its performance parameters, driver independent design issues and requirements, its development goals and requirements, and associated technical, management, staffing, environmental, and other developmental and operational issues. The second phase addresses driver-dependent issues such as specific design, range of performance capabilities, and cost. The study includes four driver options; the neodymium-glass solid state laser, the krypton fluoride excimer gas laser, the light-ion accelerator, and the heavy-ion induction linear accelerator. The results of the Phase II study are described in the present report.

Not Available

1993-05-01

105

Rodents And Other Gnawers.  

ERIC Educational Resources Information Center

Presents information about rodents and lagomorphs, including definitions and the characteristics of these animals. Contains teaching activities such as "Habitats for Hoppers,""Cartoon Gnawers," and "The Great Rodent Expedition." Reproducible handouts for two of the activities are provided. (TW)

Naturescope, 1986

1986-01-01

106

Novel technology for modulating locomotor activity as an operant response in the mouse: implications for neuroscience studies involving "exercise" in rodents.  

PubMed

We have developed a novel, low-cost device designed to monitor and modulate locomotor activity in murine subjects. This technology has immediate application to the study of effects of physical exercise on various neurobiological endpoints, and will also likely be useful in the study of psychomotor sensitization and drug addiction. Here we demonstrate the capacity of these devices to establish locomotor activity as an operant response reinforced by food pellet presentations, and show that schedules of reinforcement can reliably control this behavior. Importantly, these data show that varying degrees of increased locomotor activity (in other words, "exercise") can be elicited and maintained in mice by manipulating the schedule of reinforcement. Our findings argue that the present technology might reduce the imposition of stress and motivational bias inherent in more traditional procedures for establishing exercise in laboratory rodents, while allowing for true random assignment to experimental groups. As interest in physical exercise as a modulating factor in numerous clinical conditions continues to grow, technologies like the one proposed here are likely to become critical in conducting future experiments along these lines. PMID:23164960

Fantegrossi, William E; Xiao, Wendy R; Zimmerman, Sarah M

2012-11-16

107

Chapter 4.6 Genetic factors underlying anxiety-behavior: A meta-analysis of rodent studies involving targeted mutations of neurotransmission genes  

Microsoft Academic Search

This paper aimed at reviewing publications investigating the involvement of genetic factors in anxiety behavior, using a meta-analysis of rodent studies involving targeted mutations of neurotransmission genes. We summarized 311 experiments investigating the involvement of GABAergic, serotoninergic, glutamatergic, and neuropeptidergic targets, and then analyzed these tables according several questions such as: Are some particular behavioral tests used in these studies?

Catherine Belzung; Samuel Leman; Guy Griebel

2008-01-01

108

EPA-HONDA Emission Laboratory Correlation Study.  

National Technical Information Service (NTIS)

A laboratory correlation program between the EPA Motor Vehicle Emission Laboratory (MVEL) and the new Ann Arbor Honda emission test laboratory has been completed. Statistical analysis of data are reported from a 1976 Honda Civic CVCC tested for exhaust em...

1975-01-01

109

Laboratory Animal Science Issues in the Design and Conduct of Studies with Endocrine-active Compounds  

Microsoft Academic Search

The use of rodent models for research and testing on endo- crine-active compounds necessitates an awareness of a number of laboratory animal science issues to standardize bioassay methods and facilitate reproducibility of results between laboratories. These issues are not unique to endo- crine research but are particularly important in this field due to the complexities and interdependencies of the endocrine

Jeffrey I. Everitt; Paul M. D. Foster

2004-01-01

110

An experimental study of the impacts of understorey forest vegetation and herbivory by red deer and rodents on seedling establishment and species composition in Waitutu Forest, New Zealand  

Microsoft Academic Search

Introduced mammalian herbivores are changing the structure and composition of New Zealand's forest ecosystems and may modify forest succession after natural disturbances. We studied how introduced ungulates (red deer and feral pigs) and rodents (rats and house mice) affected the rate of recovery (i.e. the engineering resilience) of the forest understorey following artificial disturbance. We imposed disturbances by clearing understorey

Deborah J. Wilson; Wendy A. Ruscoe; Larry E. Burrows; Lisa M. McElrea; David Choquenot

111

Laboratory studies of petal-shaped occulters  

NASA Astrophysics Data System (ADS)

We present laboratory studies of scaled occulting starshades for the New Worlds Observer (NWO). A deep reactive ion etched silicon starshade has been fabricated by NIST, designed to cover the same number of Fresnel zones as in the proposed mission. The broadband shadow is mapped with a photometer in a dark vacuum tunnel fed by a heliostat at HAO. CCD images provide direct contrast measurements of different features around the starshade. Preliminary measurements reach 5x10-6 suppression in the center of the shadow at the focal plane. The two-dimensional structure of the starshade diffraction pattern is compared to that produced by the Fresnel integral.

Schindhelm, E.; Shipley, A.; Oakley, P.; Leviton, D.; Cash, W.; Card, G.

2007-09-01

112

High Resolution Laboratory Studies for Astronomical Spectroscopy  

NASA Astrophysics Data System (ADS)

Understanding astronomical observations of molecules requires detailed spectroscopic data that can only be derived from laboratory studies. These data, including accurate transition frequencies, intensities, broadening coefficients, and collisional rates are essential for the proper characterization of the physics, chemistry, and dynamics of astronomical sources. Equally important is the comprehensive spectroscopic characterization of astronomical molecules in multiple wavelength regions. A strong effort is in place in the JPL Molecular Spectroscopy Group to provide fundamental knowledge to support ground-, aircraft-, and space-based astronomical spectroscopy. A synopsis of the high-resolution laboratory spectroscopy of astronomical molecules at JPL is presented, highlighting benchmark studies that span wavelengths from the radio to the optical. The systems under study include molecules that are ubiquitous in the interstellar medium and/or exoplanetary atmospheres (CH4, CO2, H2O, and NH3), as well as ones that have recently been shown to be important constituents of the interstellar gas (O2, CH3OH, H3O+, and HCl+).

Gupta, Harshal; Brown, L. R.; Drouin, B. J.; Miller, C. E.; Pearson, J. C.; Sung, K.; Yu, S.

2012-05-01

113

FELASA guidelines for the refinement of methods for genotyping genetically-modified rodents: a report of the Federation of European Laboratory Animal Science Associations Working Group.  

PubMed

The use of genetically-modified (GM) animals as research models continues to grow. The completion of the mouse genome sequence, together with the high-throughput international effort to introduce mutations across the mouse genome in the embryonic stem (ES) cells (www.knockoutmouse.org) facilitates an efficient way to obtain mutated mouse strains as research models. The increasing number of available mutated mouses trains and their combinations, together with the increasing complexity in the targeting approaches used,reinforces the need for guidelines that will provide information about the mouse strains and the robust and reliable methods used for their genotyping. This information, however, should be obtained with a method causing minimal discomfort to the experimental animals. We have, therefore, compiled the present document which summarizes the currently available methods for obtaining genotype information. It provides updated guidelines concerning animal identification, DNA sampling and genotyping, and the information to be kept and distributed for any mutated rodent strain. PMID:23479772

Bonaparte, Dolores; Cinelli, Paolo; Douni, Eleni; Hérault, Yann; Maas, Maas; Pakarinen, Pirjo; Poutanen, Matti; Lafuente, Mirentxu Santos; Scavizzi, Ferdinando

2013-07-01

114

A guide for measurement of circulating metabolic hormones in rodents: Pitfalls during the pre-analytical phase  

PubMed Central

Researchers analyse hormones to draw conclusions from changes in hormone concentrations observed under specific physiological conditions and to elucidate mechanisms underlying their biological variability. It is, however, frequently overlooked that also circumstances occurring after collection of biological samples can significantly affect the hormone concentrations measured, owing to analytical and pre-analytical variability. Whereas the awareness for such potential confounders is increasing in human laboratory medicine, there is sometimes limited consensus about the control of these factors in rodent studies. In this guide, we demonstrate how such factors can affect reliability and consequent interpretation of the data from immunoassay measurements of circulating metabolic hormones in rodent studies. We also compare the knowledge about such factors in rodent studies to recent recommendations established for biomarker studies in humans and give specific practical recommendations for the control of pre-analytical conditions in metabolic studies in rodents.

Bielohuby, Maximilian; Popp, Sarah; Bidlingmaier, Martin

2012-01-01

115

Diet, caloric restriction, and the rodent bioassay  

Microsoft Academic Search

The diet can significantly alter the results of toxicity and carci- nogenicity studies. Ad libitum (AL) overfeeding of excessive calo- ries to sedentary adult rodents is one of the most poorly controlled variables affecting the current rodent bioassay. AL-overfed ro- dents develop an early onset of adverse metabolic events, endo- crine-disruptive degenerative diseases, and tumors that result in early morbidity

Kevin P. Keenan; Gordon C. Ballam; Keith A. Soper; Philippe Laroque; John B. Coleman; Rakesh Dixit

1999-01-01

116

Modeling panic disorder in rodents.  

PubMed

Panic disorder (PD) is a subtype of anxiety disorder in which the core phenomenon is the spontaneous occurrence of panic attacks. Although studies with laboratory animals have been instrumental for the understanding of its neurobiology and treatment, few review articles have focused on the validity of the currently used animal models for studying this psychopathology. Therefore, the aim of the present paper is to discuss the strengths and limits of these models in terms of face, construct and predictive validity. Based on the hypothesis that panic attacks are related to defensive responses elicited by proximal threat, most animal models measure the escape responses induced by specific stimuli. Some apply electrical or chemical stimulation to brain regions proposed to modulate fear and panic responses, such as the dorsal periaqueductal grey or the medial hypothalamus. Other models focus on the behavioural consequences caused by the exposure of rodents to ultrasound or natural predators. Finally, the elevated T-maze associates a one-way escape response from an open arm with panic attacks. Despite some limitations, animal models are essential for a better understanding of the neurobiology and pharmacology of PD and for discovering more effective treatments. PMID:23584609

Moreira, Fabrício A; Gobira, Pedro H; Viana, Thércia G; Vicente, Maria A; Zangrossi, Hélio; Graeff, Frederico G

2013-04-13

117

A laboratory study of tracer tomography  

NASA Astrophysics Data System (ADS)

A tracer tomographic laboratory study was performed with consolidated fractured rock in three-dimensional space. The investigated fractured sandstone sample was characterized by significant matrix permeability. The laboratory transport experiments were conducted using gas-flow and gas-tracer transport techniques that enable the generation of various flow-field patterns via adjustable boundary conditions within a short experimental time period. In total, 72 gas-tracer (helium) tests were performed by systematically changing the injection and monitoring configuration after each test. For the inversion of the tracer breakthrough curves an inversion scheme was applied, based on the transformation of the governing transport equation into a form of the eikonal equation. The reliability of the inversion results was assessed with singular value decomposition of the trajectory density matrix. The applied inversion technique allowed for the three-dimensional reconstruction of the interstitial velocity with a high resolution. The three-dimensional interstitial velocity distribution shows clearly that the transport is dominated by the matrix while the fractures show no apparent influence on the transport responses.

Brauchler, R.; Böhm, G.; Leven, C.; Dietrich, P.; Sauter, M.

2013-09-01

118

A phylogeographic study of the endemic rodent Eliurus carletoni (Rodentia: Nesomyinae) in an ecological transition zone of Northern Madagascar.  

PubMed

We conducted a mitochondrial phylogeographic study of the endemic dry forest rodent Eliurus carletoni (Rodentia: Nesomyinae) in an ecological transition zone of northern Madagascar (Loky-Manambato) and 2 surrounding regions (Ankarana and Analamerana). The main goal was to assess the evolutionary consequences on this taxon of the complex landscape features and Quaternary ecological vicissitudes. Three haplogroups were identified from the 215 specimens obtained from 15 populations. High levels of genetic diversity and significant genetic differentiation among populations were observed. The different geographical subdivisions of the study area by regions, by river catchment zones, and the physical distance between populations are not correlated with genetic patterns. In contrast, population structure is mostly explained by the geographic distribution of the samples among existing forest blocks. E. carletoni experienced a genetic bottleneck between 18 750 and 7500 years BP, which correlates with periods when moister climates existed on the island. Overall, our data suggest that the complex genetic patterns of E. carletoni can be explained by Quaternary climatic vicissitudes that resulted in habitat fluctuations between dry and humid forests, as well as subsequent human-induced fragmentation of forest habitat. PMID:23132906

Rakotoarisoa, Jean-Eric; Raheriarisena, Martin; Goodman, Steven M

2012-11-05

119

Ecological and Control Techniques for Sand Flies (Diptera: Psychodidae) Associated with Rodent Reservoirs of Leishmaniasis  

PubMed Central

Background Leishmaniasis remains a global health problem because of the substantial holes that remain in our understanding of sand fly ecology and the failure of traditional vector control methods. The specific larval food source is unknown for all but a few sand fly species, and this is particularly true for the vectors of Leishmania parasites. We provide methods and materials that could be used to understand, and ultimately break, the transmission cycle of zoonotic cutaneous leishmaniasis. Methods and Findings We demonstrated in laboratory studies that analysis of the stable carbon and nitrogen isotopes found naturally in plant and animal tissues was highly effective for linking adult sand flies with their larval diet, without having to locate or capture the sand fly larvae themselves. In a field trial, we also demonstrated using this technique that half of captured adult sand flies had fed as larvae on rodent feces. Through the identification of rodent feces as a sand fly larval habitat, we now know that rodent baits containing insecticides that have been shown in previous studies to pass into the rodents' feces and kill sand fly larvae also could play a future role in sand fly control. In a second study we showed that rubidium incorporated into rodent baits could be used to demonstrate the level of bloodfeeding by sand flies on baited rodents, and that the elimination of sand flies that feed on rodents can be achieved using baits containing an insecticide that circulates in the blood of baited rodents. Conclusions Combined, the techniques described could help to identify larval food sources of other important vectors of the protozoa that cause visceral or dermal leishmaniasis. Unveiling aspects of the life cycles of sand flies that could be targeted with insecticides would guide future sand fly control programs for prevention of leishmaniasis.

Mascari, Thomas M.; Hanafi, Hanafi A.; Jackson, Ryan E.; Ouahabi, Souad; Ameur, Btissam; Faraj, Chafika; Obenauer, Peter J.; Diclaro, Joseph W.; Foil, Lane D.

2013-01-01

120

Oral treatment of rodents with fipronil for feed-through and systemic control of sand flies (Diptera: Psychodidae).  

PubMed

The sand fly Phlebotomus papatasi Scopoli is the vector of Leishmania major (Yakimoff & Schokhor), which is maintained in populations of burrowing rodents. The purpose of this study was to conduct a laboratory study to determine the efficacy of oral treatment of rodents with fipronil for control of sand flies that feed on rodent feces as larvae or on rodent blood as adults. We determined through larval bioassays that fipronil was eliminated in feces of orally-treated hamsters at a level that was significantly toxic to sand fly larvae for 21 d after the hamsters had been withdrawn from a fipronil-treated diet. Through bloodfeeding bioassays, we also found that fipronil was present in the peripheral blood of hamsters at a concentration that was significantly toxic to bloodfeeding adult female sand flies for 49 d after the hamsters had been withdrawn from their treated diet. The results of this study suggest that fipronil acts as well as or better than feed-through or systemic insecticides that previously have been measured against sand flies, and is particularly promising because this single compound acts against both larvae and bloodfeeding adults. An area-wide approach using rodent baits containing a fipronil could suppress vector populations that originate in the vicinity of rodent reservoirs, and could be used to eliminate the most epidemiologically important part of the vector population: female sand flies that take bloodmeals on rodent reservoirs. PMID:23427660

Mascari, T M; Stout, R W; Foil, L D

2013-01-01

121

Review of the literature and suggestions for the design of rodent survival studies for the identification of compounds that increase health and life span.  

PubMed

Much of the literature describing the search for agents that increase the life span of rodents was found to suffer from confounds. One-hundred-six studies, absent 20 contradictory melatonin studies, of compounds or combinations of compounds were reviewed. Only six studies reported both life span extension and food consumption data, thereby excluding the potential effects of caloric restriction. Six other studies reported life span extension without a change in body weight. However, weight can be an unreliable surrogate measure of caloric consumption. Twenty studies reported that food consumption or weight was unchanged, but it was unclear whether these data were anecdotal or systematic. Twenty-nine reported extended life span likely due to induced caloric restriction. Thirty-six studies reported no effect on life span, and three a decrease. The remaining studies suffer from more serious confounds. Though still widely cited, studies showing life span extension using short-lived or "enfeebled" rodents have not been shown to predict longevity effects in long-lived animals. We suggest improvements in experimental design that will enhance the reliability of the rodent life span literature. First, animals should receive measured quantities of food and its consumption monitored, preferably daily, and reported. Weights should be measured regularly and reported. Second, a genetically heterogeneous, long-lived rodent should be utilized. Third, chemically defined diets should be used. Fourth, a positive control (e.g., a calorically restricted group) is highly desirable. Fifth, drug dosages should be chosen based on surrogate endpoints or accepted cross-species scaling factors. These procedures should improve the reliability of the scientific literature and accelerate the identification of longevity and health span-enhancing agents. PMID:21424790

Spindler, Stephen Richard

2011-03-22

122

Laboratory studies of cometary ice analogues  

NASA Astrophysics Data System (ADS)

Laboratory studies were performed in order to simulate the physico-chemical processes that are likely to occur in the near surface layers of short and intermediate period comets. Pure H2O ice as well as CO:H2O, CO2:H2O, CH4:H2O, CO:CO2:H2O, and NH3:H2O ice mixtures were studied in the temperature range between 10 and 180 K. The evolution of the composition of ice mixtures, the crystallization of H2O ice as well as the formation and decompostion of clathrate hydrate by different processes were studied as a function of temperature and time. Using the results together with numerical modeling, predictions are made about the survival of amorphous ice, CO, CO2, CH4, and NH3 in the near surface layers of short period comets. The likeliness of finding clathrate and molecular hydrates is discussed. It is proposed that the analytical methods developed here could be fruitfully adapted to the analysis of returned comet samples.

Schmitt, B.; Espinasse, S.; Grim, R. J. A.; Greenberg, J. M.; Klinger, J.

1989-12-01

123

Mathematical models for hantavirus infection in rodents.  

PubMed

Hantavirus pulmonary syndrome is an emerging disease of humans that is carried by wild rodents. Humans are usually exposed to the virus through geographically isolated outbreaks. The driving forces behind these outbreaks is poorly understood. Certainly, one key driver of the emergence of these viruses is the virus population dynamics within the rodent population. Two new mathematical models for hantavirus infection in rodents are formulated and studied. The new models include the dynamics of susceptible, exposed, infective, and recovered male and female rodents. The first model is a system of ordinary differential equations while the second model is a system of stochastic differential equations. These new models capture some of the realistic dynamics of the male/female rodent hantavirus interaction: higher seroprevalence in males and variability in seroprevalence levels. PMID:16794943

Allen, Linda J S; McCormack, Robert K; Jonsson, Colleen B

2006-04-01

124

VALIDATION STUDY DESIGN TO EVALUATE IN VITRO CYTOTOXICITY ASSAYS FOR PREDICTING RODENT AND HUMAN ACUTE SYSTEMIC TOXICITY VALIDATION STUDY DESIGN TO EVALUATE IN VITRO CYTOTOXICITY ASSAYS FOR PREDICTING RODENT AND HUMAN ACUTE SYSTEMIC TOXICITY  

Microsoft Academic Search

The Interagency Coordinating Committee on the Validation of Alternative Methods (ICCVAM) and NICEATM convened an international workshop in October 2000 to evaluate the validation status of in vitro methods for predicting acute systemic toxicity. Workshop participants recommended that two in vitro cytotoxicity methods should be further evaluated to determine their usefulness for predicting rodent and human acute toxicity. The NICEATM

WS Stokes; M Balls; JA Strickland; A Worth; S Casati; RR Tice

125

Safety assessment of mushroom ?-glucan: Subchronic toxicity in rodents and mutagenicity studies  

Microsoft Academic Search

Mushroom ?-glucan, a polymer of ?-(1,3\\/1,6)-glucan, has been claimed for its health benefits. The objective of this study was to assess the safety in-use of mushroom ?-glucan as dietary supplement and food ingredient. Hence, a subchronic toxicity and mutagenicity studies were conducted. In the subchronic toxicity study, Sprague Dawley rats (12\\/sex\\/group) were administered (gavage) mushroom ?-glucan at dose levels of

S. N. Chen; F. H. Nan; J. F. Wu; C. L. Lu; Madhu G. Soni

2011-01-01

126

Rodent phylogeny revised: analysis of six nuclear genes from all major rodent clades  

PubMed Central

Background Rodentia is the most diverse order of placental mammals, with extant rodent species representing about half of all placental diversity. In spite of many morphological and molecular studies, the family-level relationships among rodents and the location of the rodent root are still debated. Although various datasets have already been analyzed to solve rodent phylogeny at the family level, these are difficult to combine because they involve different taxa and genes. Results We present here the largest protein-coding dataset used to study rodent relationships. It comprises six nuclear genes, 41 rodent species, and eight outgroups. Our phylogenetic reconstructions strongly support the division of Rodentia into three clades: (1) a "squirrel-related clade", (2) a "mouse-related clade", and (3) Ctenohystrica. Almost all evolutionary relationships within these clades are also highly supported. The primary remaining uncertainty is the position of the root. The application of various models and techniques aimed to remove non-phylogenetic signal was unable to solve the basal rodent trifurcation. Conclusion Sequencing and analyzing a large sequence dataset enabled us to resolve most of the evolutionary relationships among Rodentia. Our findings suggest that the uncertainty regarding the position of the rodent root reflects the rapid rodent radiation that occurred in the Paleocene rather than the presence of conflicting phylogenetic and non-phylogenetic signals in the dataset.

Blanga-Kanfi, Shani; Miranda, Hector; Penn, Osnat; Pupko, Tal; DeBry, Ronald W; Huchon, Dorothee

2009-01-01

127

40 CFR 799.9305 - TSCA Repeated dose 28-day oral toxicity study in rodents.  

Code of Federal Regulations, 2013 CFR

...specific gravity, pH, protein, glucose and blood and blood cells. (iii) In addition, studies to investigate serum markers...route of administration to cover systemic effects), peripheral nerve (sciatic or tibial) preferably in close proximity to...

2013-07-01

128

Study of Transmission and Distribution Laboratory Facilities.  

National Technical Information Service (NTIS)

A comprehensive survey of existing laboratories and field test facilities, capable of conducting transmission and distribution research, in the United States and Canada and similar well-known facilities located in Europe was made. Major areas covered by t...

1975-01-01

129

Controlled Atmosphere System Laboratory Studies on Tomatoes.  

National Technical Information Service (NTIS)

Laboratory tests were conducted to determine the effect of low-oxygen controlled atmosphere (which is carbon dioxide free) on tomatoes. Storage periods approximating the extended overseas distribution time of 3 to 8 weeks as required for military shipment...

H. Gorfien A. R. Rahman G. Taylor D. E. Westcott

1970-01-01

130

Safety assessment of mushroom ?-glucan: subchronic toxicity in rodents and mutagenicity studies.  

PubMed

Mushroom ?-glucan, a polymer of ?-(1,3/1,6)-glucan, has been claimed for its health benefits. The objective of this study was to assess the safety in-use of mushroom ?-glucan as dietary supplement and food ingredient. Hence, a subchronic toxicity and mutagenicity studies were conducted. In the subchronic toxicity study, Sprague Dawley rats (12/sex/group) were administered (gavage) mushroom ?-glucan at dose levels of 0, 500, 1000 and 2000 mg/kg body weight (bw)/day for 90 days. As compared to control group, administration of ?-glucan did not result in any toxicologically significant treatment-related changes in clinical observations, ophthalmic examinations, body weights, body weight gains, feed consumption, and organ weights. No adverse effects of the ?-glucan on the hematology, serum chemistry parameters, urinalysis or terminal necropsy (gross or histopathology findings) were noted. The results of mutagenicity studies as evaluated by gene mutations in Salmonella typhimurium, in vitro chromosome aberrations and in vivo micronucleus test in mouse did not reveal any genotoxicity of ?-glucan. Based on the subchronic study, the no observed-adverse-effect level (NOAEL) for mushroom ?-glucan was determined as 2000 mg/kgbw/day, the highest dose tested. PMID:21856366

Chen, S N; Nan, F H; Chen, S; Wu, J F; Lu, C L; Soni, Madhu G

2011-08-12

131

Production of butter fat rich in trans10-C18:1 for use in biomedical studies in rodents.  

PubMed

Trans fatty acids are suspected to be detrimental to health, particularly to cardiovascular function. Trans fatty acids include a wide range of fatty acids, with isomers of C18:1, conjugated and non-conjugated C18:2 as major components. A vaccenic acid (trans11-C18:1) + rumenic acid (cis9,trans11-CLA)-rich butter has been shown previously to exhibit health beneficial effects, but less is known concerning another trans-C18:1 present in hydrogenated vegetable oil-based products and sometimes in milk fat, the trans10-isomer. The present experiment was conducted to produce butters from milk of variable fatty acid composition for use in biomedical studies with rodents, with the overall aim of evaluating the specific effect of trans10-C18:1 and trans11-C18:1 + cis9,trans11-CLA on cardiovascular function. Milks from lactating dairy cows fed two types of maize-based diets supplemented (5% of dry matter)--or not--with sunflower oil were collected, and used to manufacture butters either rich in trans10-C18:1 (14% of total fatty acids, 64.5% of fat content) or rich in trans11-C18:1 + cis9,trans11-CLA (7.4 and 3.1% of total fatty acids, respectively, 68.5% of fat content), or with standard fatty acid composition (70% of fat content). Additionally, total saturated fatty acid percentage was reduced by more than one third in the enriched butters compared with the standard butter. An understanding of the role of nutrition on milk fatty acid composition in cows allows for the production of dairy products of variable lipid content and composition for use in biomedical studies in animal models and human subjects. PMID:16597427

Roy, Alexandre; Ferlay, Anne; Chilliard, Yves

2006-04-06

132

Studies on preventive and curative effects of berberine on chemical-induced hepatotoxicity in rodents  

Microsoft Academic Search

Berberis aristata is an edible plant employed in the South Asian Traditional Medicine, particularly its fruits being used as a tonic remedy for liver and heart. In this investigation, berberine, a known compound from this plant, was studied for its possible antihepatotoxic action in rats. Pretreatment of animals with berberine (4 mg\\/kg; orally twice daily for 2 days) prevented the

K. H Janbaz; A. H Gilani

2000-01-01

133

Allometric disparity in rodent evolution.  

PubMed

In this study, allometric trajectories for 51 rodent species, comprising equal representatives from each of the major clades (Ctenohystrica, Muroidea, Sciuridae), are compared in a multivariate morphospace (=allometric space) to quantify magnitudes of disparity in cranial growth. Variability in allometric trajectory patterns was compared to measures of adult disparity in each clade, and dietary habit among the examined species, which together encapsulated an ecomorphological breadth. Results indicate that the evolution of allometric trajectories in rodents is characterized by different features in sciurids compared with muroids and Ctenohystrica. Sciuridae was found to have a reduced magnitude of inter-trajectory change and growth patterns with less variation in allometric coefficient values among members. In contrast, a greater magnitude of difference between trajectories and an increased variation in allometric coefficient values was evident for both Ctenohystrica and muroids. Ctenohystrica and muroids achieved considerably higher adult disparities than sciurids, suggesting that conservatism in allometric trajectory modification may constrain morphological diversity in rodents. The results provide support for a role of ecology (dietary habit) in the evolution of allometric trajectories in rodents. PMID:23610638

Wilson, Laura A B

2013-03-05

134

Allometric disparity in rodent evolution  

PubMed Central

In this study, allometric trajectories for 51 rodent species, comprising equal representatives from each of the major clades (Ctenohystrica, Muroidea, Sciuridae), are compared in a multivariate morphospace (=allometric space) to quantify magnitudes of disparity in cranial growth. Variability in allometric trajectory patterns was compared to measures of adult disparity in each clade, and dietary habit among the examined species, which together encapsulated an ecomorphological breadth. Results indicate that the evolution of allometric trajectories in rodents is characterized by different features in sciurids compared with muroids and Ctenohystrica. Sciuridae was found to have a reduced magnitude of inter-trajectory change and growth patterns with less variation in allometric coefficient values among members. In contrast, a greater magnitude of difference between trajectories and an increased variation in allometric coefficient values was evident for both Ctenohystrica and muroids. Ctenohystrica and muroids achieved considerably higher adult disparities than sciurids, suggesting that conservatism in allometric trajectory modification may constrain morphological diversity in rodents. The results provide support for a role of ecology (dietary habit) in the evolution of allometric trajectories in rodents.

Wilson, Laura A B

2013-01-01

135

Interagency Study of Federal Laboratory Technology Transfer Organization and Operation.  

National Technical Information Service (NTIS)

This report is the result of a baseline study of technology transfer organization and operation in Federal laboratories, and is an analysis of responses to two information-gathering instruments: the Federal Laboratory ORTA Organizational and Operational I...

1985-01-01

136

Observed incidence of tumorigenesis in long-term rodent studies of rAAV vectors  

Microsoft Academic Search

Gene therapy using recombinant adeno-associated virus vectors (rAAV) is generally considered safe. During the course of a study designed to determine the long-term efficacy of rAAV-mediated gene therapy initiated in newborn mice with the lysosomal storage disease, mucopolysaccharidosis type VII (MPSVII), a significant incidence of hepatocellular carcinomas and angiosarcomas was discovered. A hepatocellular carcinoma was first detected in a 35-week-old

A Donsante; C Vogler; N Muzyczka; JM Crawford; J Barker; T Flotte; M Campbell-Thompson; T Daly; M S Sands; Sands

2001-01-01

137

Comparative study of chloroquine and quinine on malaria rodents and their effects on the mouse testis  

PubMed Central

Objective To evaluate the effects of quinine and chloroquine against male mice infected with Plasmodium berghei and their adverse effects on the mice testes. Methods In this study, 48 adult male mice, (20–25 g), aged 8 to 12 weeks were divided into four groups. This study was carried out from December 2009 until May 2010 in the School of Public Health, Tehran University of Medical Sciences. Results The results showed that 58.33% of mice treated with chloroquine were completely recovered. Parasitemia was 4% on day 8 when compared to that on day 0, whereas it was 9% on day 9. There was no orchitis found in this group. The mortality of mice after exposing to quinine on day 5 was 8.3%, whereas from day 10 to day 14 it was 91.7%. We found 75% orchitis occurred in quinine treated group. There was a significant difference between quinine and chloroquine effects on the parasite and also mice testes (P<0.05). Conclusions In this study, It can be concluded that male mice have full resistance to the quinine. Quinine does not only make male mice recover completely, but also cause inflammation on mice testicles tissue.

Abolghasemi, Esmail; Moosa-Kazemi, Seyed Hassan; Davoudi, Maryam; Reisi, Ahmad; Satvat, Mohammad Taghi

2012-01-01

138

Two-year toxicity and carcinogenicity studies of ampicillin trihydrate and penicillin VK in rodents.  

PubMed

Toxicology and carcinogenesis studies of ampicillin trihydrate and penicillin VK, two widely used beta-lactam antibiotics, were performed in F344/N rats and B6C3F1 mice. In these studies ampicillin trihydrate was administered for 2 years to rats at doses of 0, 750, or 1500 mg/kg and to mice at doses of 0, 1500, or 3000 mg/kg, and penicillin VK was administered to rats and mice at doses of 0, 500, or 1000 mg/kg. Both drugs were administered by oral gavage in corn oil. Toxic lesions of the stomach were seen in rats and mice after ampicillin trihydrate administration and in mice after penicillin VK administration. In male rats that received ampicillin trihydrate there was a marginal increase in incidence of mononuclear cell leukemia and pheochromocytomas of the adrenal gland medulla. There was no evidence for carcinogenic activity in female rats or male and female mice after ampicillin trihydrate administration or in rats and mice after penicillin VK administration. PMID:2497039

Dunnick, J K; Eustis, S L; Huff, J E; Haseman, J K

1989-02-01

139

Biphasic insulin secretion from freshly isolated or cultured, perifused rodent islets: comparative studies with rats and mice.  

PubMed

In the present report, we compared the insulin secretory responses of freshly isolated, perifused rat and mouse islets to glucose. Prestimulatory glucose levels were changed to assess their influence on the subsequent secretory responses. Additional studies included experiments with the incretin factor glucagon-like peptide-1 (GLP-1), the cholinergic agonist carbachol, and the alpha2 agonist epinephrine. Our findings demonstrate that under conditions where glucose (8.5-11.1 mmol/L) evokes a dramatic biphasic insulin secretory response from perifused rat islets, mouse islets exhibit little response. Increasing the prestimulatory glucose level to 8.5 mmol/L dramatically distorts subsequently measured glucose-induced insulin secretion from rat islets but allows the evocation of a modest but clear biphasic response from mouse islets in response to 30 mmol/L, but not 11.1 or 16.7 mmol/L, glucose. In the presence of a minimally effective glucose level (10 mmol/L), mouse islets remain exquisitely sensitive to the combined stimulatory effects of GLP-1 (2.5 nmol/L) plus carbachol (0.5 micromol/L) and to the inhibitory influence of epinephrine (10 nmol/L). Short-term culture of rat islets in CMRL 1066 containing 5.6 mmol/L glucose resulted in a significant decrease in the secretory response to 11.1 mmol/L glucose, whereas the same manipulation improved mouse islet responses. It is concluded that the process of collagenase isolating islets does not alter mouse islet sensitivity in any adverse way and that increasing the prestimulatory glucose level can indeed alter the pattern of insulin secretion in either a positive or negative manner depending upon the species being investigated. Prior short-term culture of rodent islets differentially affects secretion from these 2 species. PMID:18078856

Zawalich, Walter S; Yamazaki, Hanae; Zawalich, Kathleen C

2008-01-01

140

Biphasic Insulin Secretion from Freshly Isolated or Cultured, Perifused Rodent Islets: Comparative Studies with Rats and Mice  

PubMed Central

In the present report we compared the insulin secretory responses of freshly isolated perifused rat and mouse islets to glucose. Prestimulatory glucose levels were changed to assess its influence on the subsequent secretory responses. Additional studies included experiments with the incretin factor GLP-1, the cholinergic agonist carbachol and the ?2 agonist epinephrine. Our findings demonstrate that under conditions where glucose (8.5–11.1 mM) evokes a dramatic biphasic insulin secretory response from perifused rat islets, mouse islets exhibit little response. Increasing the prestimulatory glucose level to 8.5 mM dramatically distorts subsequently measured glucose-induced insulin secretion from rat islets but allows the evocation of a modest but clear biphasic response from mouse islets in response to 30 mM, but not 11.1 or 16.7 mM glucose. In the presence of a minimally effective glucose level (10 mM), mouse islets remain exquisitely sensitive to the combined stimulatory effects of GLP-1 (2.5 nM) plus carbachol (0.5 ?M) and to the inhibitory influence of epinephrine (10 nM). Short term culture of rat islets in CMRL-1066 containing 5.6 mM glucose resulted in a significant decrease in the secretory response to 11.1 mM glucose while the same manipulation improved mouse islet responses. It is concluded that the process of collagenase isolating islets does not alter mouse islet sensitivity in any adverse way and that increasing the prestimulatory glucose level can indeed alter the pattern of insulin secretion in either a positive or negative manner depending upon the species being investigated. Prior short term culture of rodent islets differentially affects secretion from these two species.

Zawalich, Walter S.; Yamazaki, Hanae; Zawalich, Kathleen C.

2008-01-01

141

Ultrastructural features of masseter muscle exhibiting altered occlusal relationship - a study in a rodent model  

SciTech Connect

The role of occlusion on Tempormandibular Disorders (TMD) is still unclear, mainly regarding muscular function. The aim of this study was to evaluate the occlusion highlights on masseter ultra morphology. Twenty Wistar rats were randomly divided in four groups: 10 for control group, 10 for occlusal alteration group (CCO). Rats underwent unilateral amputation of the left inferior and superior molar cusps to simulate an occlusal wear situation. The rats of control group had no occlusal wear. Half of the animals of each group was sacrificed in 14 days after the occlusal consuming and half 30 days after the occlusal consuming. The masseter muscles ipsilateral to the amputated molars were excised and processed for light microscopy, electron microscopy. The light microscopy did not show differences between the groups. The electron microscopy was able to detect a degree of intracellular damage in muscle fibers of CCO group: swollen mitochondria with disrupted cristae and cleared matrix, signs of hypercontraction of I bands and myofibril disorganization.

Lisboa, Marcio V.; Aciole, Gilberth T. S.; Oliveira, Susana C. P. S.; Marques, Aparecida M. C.; Pinheiro, Antonio L. B.; Santos, Jean N. [School of Dentistry, Federal University of Bahia, Salvador, BA, 40110-150 (Brazil); Baptista, Abrahao F.; Aguiar, Marcio C. [Biomorphology Department, Federal University of Bahia, Bahia, 40110-150 (Brazil)

2010-05-31

142

Immortalized Adult Rodent Schwann Cells as In Vitro Models to Study Diabetic Neuropathy  

PubMed Central

We have established spontaneously immortalized Schwann cell lines from normal adult mice and rats and murine disease models. One of the normal mouse cell lines, IMS32, possesses some biological properties of mature Schwann cells and high proliferative activities. The IMS32 cells under hyperglycemic and/or hyperlipidemic conditions have been utilized to investigate the pathogenesis of diabetic neuropathy, especially the polyol pathway hyperactivity, glycation, increased oxidative stress, and reduced synthesis of neurotrophic factors. In addition to the mouse cell lines, our current study focuses on the characterization of a normal rat cell line, IFRS1, under normal and high glucose conditions. These Schwann cell lines can be valuable tools for exploring the detailed mechanisms leading to diabetic neuropathy and novel therapeutic approaches against that condition.

Sango, Kazunori; Yanagisawa, Hiroko; Takaku, Shizuka; Kawakami, Emiko; Watabe, Kazuhiko

2011-01-01

143

[Study of induced effects by selective CCKB agonists cholecystokinin in the nociception and behavior in rodents].  

PubMed

Potent and selective CCK-B agonists with good bioavailability have been designed by modifying the natural CCK-8 peptide. Thus, BC 264 [Boc-Tyr(SO3H)-gNle-mGly-Trp-Me(Nle)-Asp-PheNH2] is a highly potent (0.15 nM) and selective agonist for CCK-B receptors which cross the blood brain barrier. Following i.v. injection of [3H]pBC 264 in mouse, the ligand was found in its intact form in brain tissue. Analgesic studies and in vivo binding experiments have shown that the CCKergic system could modify the release of endogenous enkephalins, whereas mu and delta opioid receptor activation modulates the release of endogenous CCK. Behavioural studies performed after local injection of CCK-8 or BC 264 into the postero-median part of the nucleus accumbens have shown the involvement of CCK-A receptors in motivation and/or emotional states of rats. In the anterior part, CCK-B receptor stimulation could be involved in attention and memory processes. BC 264 systemically administered in mice increased fear and/or "anxiety" in the black and white box test. In the elevated plus maze, BC 264 increased the emotional responses of the "anxious" rat and decreased these responses in "non anxious" animals. These results suggest that endogenous CCK could play a critical role in mood modulation through CCK-A/CCK-B receptor stimulation. Dysfunctioning of the CCK-A/CCK-B pathways could be implicated in anxiety and panic attacks. PMID:1301645

Dauge, V; Derrien, M; Durieux, C; Noble, F; Corringer, P J; Roques, B P

1992-11-01

144

ART and health: clinical outcomes and insights on molecular mechanisms from rodent studies.  

PubMed

Since the birth of the first IVF-conceived child in 1978, the use of assisted reproductive technologies (ART) has grown dramatically, contributing to the successful birth of 5 million individuals worldwide. However, there are several reported associations of ART with pregnancy complications, such as low birthweight (LBW), preterm birth, birth defects, epigenetic disorders, cancer and poor metabolic health. Whether this is attributed to ART procedures or to the subset of the population seeking ART remains a controversy, but the most relevant question today concerns the potential long-term implications of assisted conception. Recent evidence has emerged suggesting that ART-conceived children have distinct metabolic profiles that may predispose to cardiovascular pathologies in adulthood. Because the eldest IVF individuals are still too young to exhibit components of chronic middle-aged syndromes, the use of animal models has become particularly useful in describing the effects of unusual or stressful preimplantation experiences on adult fitness. Elucidating the molecular mechanisms by which embryos integrate environmental signals into development and metabolic gene expression programs will be essential for optimizing ART procedures such as in vitro culture conditions, embryo selection and transfer. In the future, additional animal studies to identify mechanisms underlying unfavorable ART outcomes, as well as more epidemiological reviews to monitor the long-term health of ART children are required, given that ART procedures have become routine medical practice. PMID:23264495

Feuer, S K; Camarano, L; Rinaudo, P F

2012-12-20

145

222-S LABORATORY FUME HOOD TESTING STUDY  

SciTech Connect

The 222-S Laboratory contains 155 active fume hoods that are used to support analytical work with radioactive and/or toxic materials. The performance of a fume hood was brought into question after employees detected odors in the work area while mixing chemicals within the subject fume hood. Following the event, testing of the fume hood was conducted to assess the performance of the fume hood. Based on observations from the testing, it was deemed appropriate to conduct performance evaluations of other fume hoods within the laboratory.

RUELAS, B.H.

2007-03-26

146

Evidence for rodent-common and species-typical limb and digit use in eating, derived from a comparative analysis of ten rodent species.  

PubMed

Order Rodentia comprises a vast portion of mammalian species (1814 species), which occupy extremely diverse habitats requiring very distinct motor specializations (e.g. burrowing, hopping, climbing, flying and swimming). Although early classification of paw use ability suggests rodents are impoverished relative to primates and make little use of their paws, there have been no systematic investigations of paw use in rodents. The present study was undertaken to describe limb/paw movements in a variety of common rodents. The movements used for handling sunflower seeds and other foods were videorecorded and analyzed in the guinea pig (Cavia porcellus), Mongolian gerbil (Meriones unguiculatus), Syrian hamster (Mesocricetus auratus), laboratory mouse (Mus musculus), laboratory rat (Rattus norvegicus), gray squirrel (Sciurus carolinensis), red squirrel (Tamiasciurus hudsonicus), Richardson's ground squirrel (Spermophilus richardsonni), prairie dog (Cynomus parvidens), and Canadian beaver (Castor americanus). The results suggested five order-common movements of food handling: (1) locating food by sniffing, (2) grasping food by mouth, (3) sitting back on the haunches to eat, (4) grasping the food using an elbow-in movement, and (5) manipulate the food with the digits. Different species displayed species-typical specializations including (1) bilateral grasping with the paws (gerbil), (2) unilateral grasping with a paw (beaver), (3) unilateral holding (ground squirrels), (4) various grip and digit postures (all species), (5) unilateral object removal from the mouth (gerbil), (6) bilateral thumb holding (squirrels), and (7) simultaneous holding/manipulation of two objects (squirrels). Only the guinea pig did not handle food with its paws, suggesting its behavior is regressive. The existence of a core pattern of paw and digit use in rodents suggests that skilled limb and paw movements originate at least with the common ancestors of the rodent, and likely the common ancestor to rodent and primate lineages, while species-typical movements suggest specialization/regression of limb use has occurred in a number of mammalian orders. PMID:9821545

Whishaw, I Q; Sarna, J R; Pellis, S M

1998-11-01

147

Gene Polymorphism Studies in a Teaching Laboratory  

ERIC Educational Resources Information Center

I present a laboratory procedure for illustrating transcription, post-transcriptional modification, gene conservation, and comparative genetics for use in undergraduate biology education. Students are individually assigned genes in a targeted biochemical pathway, for which they design and test polymerase chain reaction (PCR) primers. In this…

Shultz, Jeffry

2009-01-01

148

Gene Polymorphism Studies in a Teaching Laboratory  

ERIC Educational Resources Information Center

|I present a laboratory procedure for illustrating transcription, post-transcriptional modification, gene conservation, and comparative genetics for use in undergraduate biology education. Students are individually assigned genes in a targeted biochemical pathway, for which they design and test polymerase chain reaction (PCR) primers. In this…

Shultz, Jeffry

2009-01-01

149

Laboratory studies of hard rock for CAES  

SciTech Connect

A program is summarized which investigated the properties of hard rock specimens, from formations suitable for CAES that are subject to the conditions envisioned for a CAES cavern by means of laboratory scale testing. It is concluded that although the compressive and tensile strengths are adversely influenced by a Compressed Air Energy Storage Cavern environment, the reduced failure strength of hard rocks is sufficiently high to indicate that a CAES plant could be operated satisfactorily.

Fossum, A.F.

1980-10-01

150

Laboratory studies of hard rock for CAES  

NASA Astrophysics Data System (ADS)

The properties of hard rock specimens, from formations suitable for compressed air energy storage (CAES) that are subject to the conditions envisioned for a CAES cavern, were investigated by means of laboratory testing. It was concluded that although the compressive and tensile strengths are adversely influenced by a CAES cavern environment, the reduced failure strength of hard rocks is sufficiently high to indicate that a CAES plant could be operated satisfactorily.

Fossum, A. F.

1980-10-01

151

Laboratory Needs for Interstellar Ice Studies  

NASA Astrophysics Data System (ADS)

A large fraction of the molecules in dense interstellar and circumstellar environments is stored in icy grain mantles. The mantles are formed by a complex interplay between chemical and physical processes. Key questions on the accretion and desorption processes and the chemistry on the grain surfaces and within the icy mantles can only be answered by laboratory experiments. Recent infrared (2-30 micron) spectroscopic surveys of large samples of Young Stellar Objects (YSOs) and background stars tracing quiescent cloud material have shown that the ice band profiles and depths vary considerably as a function of environment. Using laboratory spectra in the identification process, it is clear that a rather complex mixture of simple species (CH3OH, CO2, H2O, CO) exists even in the quiescent cloud phase. Variations of the local physical conditions (CO freeze out) and time scales (CH3OH formation) appear to be key factors in the observed variations. Sublimation and thermal processing dominate as YSOs heat their environments. The identification of several ice absorption features is still disputed. I will outline laboratory work (e.g., on salts, PAHs, and aliphatic hydrocarbons) needed to further constrain the ice band identification as well as the thermal and chemical history of the carriers. Such experiments will also be essential to interpret future high spectral resolution SOFIA and JWST observations.

Boogert, Abraham C. A.

2012-05-01

152

Gene Polymorphism Studies in a Teaching Laboratory  

NASA Astrophysics Data System (ADS)

I present a laboratory procedure for illustrating transcription, post-transcriptional modification, gene conservation, and comparative genetics for use in undergraduate biology education. Students are individually assigned genes in a targeted biochemical pathway, for which they design and test polymerase chain reaction (PCR) primers. In this example, students used genes annotated for the steroid biosynthesis pathway in soybean. The authoritative Kyoto encyclopedia of genes and genomes (KEGG) interactive database and other online resources were used to design primers based first on soybean expressed sequence tags (ESTs), then on ESTs from an alternate organism if soybean sequence was unavailable. Students designed a total of 50 gene-based primer pairs (37 soybean, 13 alternative) and tested these for polymorphism state and similarity between two soybean and two pea lines. Student assessment was based on acquisition of laboratory skills and successful project completion. This simple procedure illustrates conservation of genes and is not limited to soybean or pea. Cost per student estimates are included, along with a detailed protocol and flow diagram of the procedure.

Shultz, Jeffry

2009-02-01

153

[Study of Hantavirus seoul in a human and rodent population from a marginal area in Buenos Aires City].  

PubMed

A sero-epidemiological survey was conducted to detect evidence of the circulation of Hantavirus seoul. This virus of worldwide distribution is associated with hemorrhagic fever with renal syndrome. A total of 106 samples from people who live in a marginal area in Buenos Aires City and 29 Rattus norvegicus captured in the surroundings of their houses were tested for specific antibodies. Thirty five samples from hypertensive patients undergoing a follow up health program, living in the same neighbourhood, were also tested. The antibody prevalence in rodents was 31% while no evidence of infection was found in the human samples. PMID:12876901

Seijo, Alfredo; Pini, Noemí; Levis, Silvana; Coto, Héctor; Deodato, Bettina; Cernigoi, Beatriz; de Bassadoni, Diana; Enría, Delia

2003-01-01

154

Social biology of rodents.  

PubMed

Herein, I summarize some basic components of rodent social biology. The material in this paper is summarized and condensed from a recent book "Rodent Societies: An Ecological and Evolutionary Perspective" edited by J. O. Wolff and P. W. Sherman (2007). I describe the four basic spacing patterns and illustrate how female territoriality is a function of offspring defense and male mating tactics are a function of female defensibility. The vulnerability of young to infanticide shapes female spacing and mating behavior. Food does not appear to be a defensible resource for rodents, except for those species that larder hoard nonperishable items such as seeds. Philopatry and the formation of kin groups result in genetic sub-structuring of the population, which in turn affects effective population size and genetic diversity. Dispersal is male biased and typically involves emigration from the maternal site to avoid female relatives and to seek unrelated mates. Scent marking is a major form of communication and is used in reproductive competition and to assess prospective mates, but it is also eavesdropped by predators to locate prey. Females do not appear to alter the sex ratio of litters in response to maternal condition but among arvicoline rodents daughters appear to be favored in spring and sons in autumn. Rodents are relatively monomorphic; however, females tend to be larger than males in the smallest species and smaller in the larger species. Predation risk results from an interaction among foraging time and vulnerability and in turn affects behavioral and life history characteristics. PMID:21396036

Wolff, Jerry O

2007-12-01

155

Laboratory combustion tube studies. Part II. Report SUPRI TR10  

Microsoft Academic Search

To promote a better understanding of the problems and mechanisms involved in dry in-situ combustion of crude oils in porous media, continuing laboratory studies are carried out at SUPRI. The report about the first two experiments was submitted earlier to the Department of Energy. This report describes the results of the last three tube runs. Three laboratory combustion tube studies

W. E. Brigham; M. R. Fassihi; A. Satman; R. L. Williams; P. Pettit; J. Grim; H. J. Jr. Ramey

1981-01-01

156

Endoparasites of Rodents and Their Zoonotic Importance in Germi, Dashte-Mogan, Ardabil Province, Iran  

PubMed Central

Background In order to verify the infectivity of rodents with endoparasites in Germi (Dashte-Mogan, Ardabil Province) the current study was undertaken. Methods Using live traps, 177 rodents were trapped during 2005–2007. In field laboratory, all rodents were bled prior to autopsy, frozen at ?20°C, and shipped to the School of Public Health, Tehran University of Medical Sciences, Iran. In parasitological laboratory, every rodent was dissected and its different organs were examined for the presence of any parasite. Blood thick and thin smears as well as impression smears of liver and spleen were stained with Geimsa and examined microscopically. Results Two species of rodents were trapped; Meriones persicus (90.4%) and Microtus socialis (9.6%). The species of parasites found in M. persicus and their prevalences were as follows: Hymenolepis diminuta (38.8%), Hymenolepis nana (2.5%), Trichuris sp.(40.6), Mesocestoides larva (=tetrathyridium) (3.1%), Capillaria hepatica (6.9%), Moniliformis moniliformis (11.3%), Syphacia obvelata (2.5%), Taenia endothoracicus larva (0.6%), Physaloptera sp. (0.6%), Dentostomella translucida (0.6%), Heligmosomum mixtum (0.6%), Strobilocercus fasciolaris (0.6%),and Aspiculuris tetraptera (0.6%). The species of parasites found in M. socialis and their prevalences were as follows: H. diminuta (17.6%), Trichuris sp. (5.9%), Mesocestoides larva (5.9%), S. obvelata (11.8%), S. syphacia (11.8%), H. mixtum (17.6%), and Aspiculuris tetraptera (11.8%). There were no statistical differences between male and female for infectivity with parasites in either M. persicus or M. socialis. No blood or tissue protozoan parasite was found in any of the rodents examined. Conclusion Among different species identified, some had zoonotic importance. Therefore, the potential health hazard of these species needs to be considered to prevent infectivity of humans.

Kia, EB; Shahryary-Rad, E; Mohebali, M; Mahmoudi, M; Mobedi, I; Zahabiun, F; Zarei, Z; Miahipoor, A; Mowlavi, GH; Akhavan, AA; Vatandoost, H

2010-01-01

157

A Science Librarian in the Laboratory: A Case Study  

ERIC Educational Resources Information Center

|A science librarian in the laboratory can become a "point of access" for database instruction and provide a learning opportunity for students to develop their information literacy skills. A case study describes how a librarian in an organic chemistry laboratory helps the class run smoothly and identifies the science librarian as an ally and a…

Tomaszewski, Robert

2011-01-01

158

TECHNIQUES IN ASEPTIC RODENT SURGERY  

PubMed Central

Performing aseptic survival surgery in rodents can be challenging. This unit describes some basic principles to assist clinicians, researchers, and technicians in becoming proficient in performing aseptic rodent surgery.

Hoogstraten-Miller, Shelley L.; Brown, Patricia A.

2008-01-01

159

LABORATORY STUDIES OF PRIORITY POLLUTANT TREATABILITY  

EPA Science Inventory

This study investigated several methods currently available to reduce the level of pollutants in an industrial plant wastewater stream. Its purpose was to screen these treatment processes. As a result of this screening, further in-depth evaluations should be considered. The study...

160

The Laboratory and Clinical Studies of Sulfonamides.  

National Technical Information Service (NTIS)

This paper reports the results of antibacterial, pharmacologic and clinical studies on the sulfonamides, trimethoprim (TMP) and sulfonamide-TMP combination manufactured in China. Bacterial sensitivity tests of these drugs were carried out on 3,549 strains...

W. Fu Z. Meifang Z. Jingde Z. Zhilin G. Yaming

1980-01-01

161

Microevolution in island rodents  

Microsoft Academic Search

We perform a meta-analysis on morphological data from four island rodent populations exhibiting microevolution (>˜?100 years). Data consisting of incidences of skeletal variants, cranial, and external measurements are from house mice (Mus musculus) on one Welsh and one Scottish island, black rats (Rattus rattus) on two Galapagos islands, and deer mice (Peromyscus maniculatus) on three California Channel islands. We report

Oliver R. W. Pergams; Mary V. Ashley

2001-01-01

162

Invasive Rodent Eradication on Islands  

Microsoft Academic Search

Invasive mammals are the greatest threat to island biodiversity and invasive rodents are likely responsible for the greatest number of extinctions and ecosystem changes. Techniques for eradicating rodents from islands were developed over 2 decades ago. Since that time there has been a significant development and application of this conservation tool. We reviewed the literature on invasive rodent eradications to

GREGG HOWALD; C. JOSH DONLAN; JUAN PABLO GALVÁN; JAMES C. RUSSELL; JOHN PARKES; ARACELI SAMANIEGO; YIWEI WANG; DICK VEITCH; PIERO GENOVESI; MICHEL PASCAL; ALAN SAUNDERS; BERNIE TERSHY

2007-01-01

163

Vermicomposting of Winery Wastes: A Laboratory Study  

Microsoft Academic Search

In Mediterranean countries, millions of tons of wastes from viticulture and winery industries are produced every year. This study describes the ability of the earthworm Eisenia andrei to compost different winery wastes (spent grape marc, vinasse biosolids, lees cakes, and vine shoots) into valuable agricultural products. The evolution of earthworm biomass and enzyme activities was tracked for 16 weeks of

ROGELIO NOGALES; CELIA CIFUENTES; EMILIO BENÍTEZ

2005-01-01

164

Laboratory and auroral studies of molecular nitrogen  

Microsoft Academic Search

Infrared and ultraviolet spectra of molecular nitrogen were obtained using a Czerny-Turner spectrograph which was converted to spectrometric operation by using a lead screw scanner to translate an exit slit focused onto a cooled intrinsic germanium photodiode detector. A rotational analysis for the 27 branches of the band studied was carried out on the 482 rotational lines identified as part

E. J. Beiting III

1978-01-01

165

Evaluating consistency in the interpretation of NTP rodent cancer bioassays: an examination of mouse lung tumor effects in the 4-MEI study.  

PubMed

The potential carcinogenicity of 4-methylimidazole (4-MEI) was evaluated in a National Toxicology Program (NTP) rodent cancer bioassay in Fischer 344 rats and B6C3F1 mice (NTP, 2007; Chan et al., 2008). The NTP concluded that there was "clear evidence of carcinogenic activity" in male and female mice, based on an increased incidence of lung tumors. The "category of evidence" that the NTP assigns to a rodent cancer bioassay outcome can have significant regulatory implications. This is especially important for 4-MEI, which forms in caramel colorings and other foods during cooking, with potential widespread human exposure in a broad spectrum of food and beverage products. A detailed analysis of all NTP mouse-lung-tumor-only carcinogens reveals that the proper call for lung tumors in the 4-MEI study should have been "some evidence" rather than "clear evidence" of carcinogenic activity for both male and female mice in order to be consistent with the NTP's interpretation of other mouse lung carcinogens showing a similar strength of response. Suggestions are given as to measures the NTP should consider in the preparation of some or all future Technical Reports in order to enhance consistency of interpretation of experimental results. PMID:23545072

Haseman, J K

2013-03-29

166

Tracking genome organization in rodents by Zoo-FISH  

Microsoft Academic Search

The number of rodent species examined by modern comparative genomic approaches, particularly chromosome painting, is limited.\\u000a The use of human whole-chromosome painting probes to detect regions of homology in the karyotypes of the rodent index species,\\u000a the mouse and rat, has been hindered by the highly rearranged nature of their genomes. In contrast, recent studies have demonstrated\\u000a that non-murid rodents

Alexander S. Graphodatsky; Fengtang Yang; Gauthier Dobigny; Svetlana A. Romanenko; Larisa S. Biltueva; Polina L. Perelman; Violetta R. Beklemisheva; Elena Z. Alkalaeva; Natalya A. Serdukova; Malcolm A. Ferguson-Smith; William J. Murphy; Terence J. Robinson

2008-01-01

167

Pharmacokinetic Studies of Norfloxacin in Laboratory Animals  

Microsoft Academic Search

Pharmacokinetic studies were conducted with norfloxacin administered by the oral and subcutaneous routes to mice and rats, and by the oral route to rhesus monkeys. The compound was moderately well absorbed following oral dosing in these animal species. Serum levels in monkeys ranged from 1.0 to 2.35 ?g\\/ml after an oral drug dose of 25 mg\\/kg of animal body weight

E. C. Gilfillan; B. A. Pelak; J. A. Bland; P. F. Malatesta; H. H. Gadebusch

1984-01-01

168

Laboratory Studies of Hydrocarbon Oxidation Mechanisms  

NASA Astrophysics Data System (ADS)

The oxidation of hydrocarbon species (alkanes, alkenes, halogenated species, and oxygenates of both natural and anthropogenic origin) in the troposphere leads to the generation of numerous potentially harmful secondary pollutants, such as ozone, organic nitrates and acids, and aerosols. These oxidations proceed via the formation of alkoxy radicals, whose complex chemistry controls the ultimate product distributions obtained. Studies of hydrocarbon oxidation mechanisms are ongoing at NCAR and Ford, using environmental chamber / FTIR absorption systems. The focus of these studies is often on the product distributions obtained at low temperature; these studies not only provide data of direct relevance to the free/upper troposphere, but also allow for a more fundamental understanding of the alkoxy radical chemistry (eg., from the determination of the Arrhenius parameters for unimolecular processes, and the quantification of the extent of the involvement of chemical activation in the alkoxy radical chemistry). In this paper, data will be presented on some or all of the following topics: kinetics/mechanisms for the reactions of OH with the unsaturated species MPAN, acrolein, and crotonaldehyde; the mechanism for the oxidation of ethyl chloride and ethyl bromide; and the mechanism for the reaction of OH with acetone and acetaldehyde at low temperature. The relevance of the data to various aspects of tropospheric chemistry will be discussed.

Orlando, J. J.; Tyndall, G. S.; Wallington, T. J.; Burkholder, J. B.; Bertman, S. B.; Chen, W.

2001-12-01

169

Laboratory Astrophysics: Study of Radiative Shocks  

NASA Astrophysics Data System (ADS)

Radiative shocks are high Mach number shocks with a strong coupling between radiation and hydrodynamics which leads to a structure governed by a radiative precursor. They might be encountered in various astrophysical systems: stellar accretion shocks, pulsating stars, interaction of supernovae with the intestellar medium etc. A numerical one dimensional (1D) stationary study of the coupling between hydrodynamics and radiative transfer is being performed. An estimate of the error made by the 1D approach in the radiative transfer treatment is done by an approximate short characteristics approach. It shows, for exemple, how much of the radiation escapes from the medium in the configuration of the experiment. The experimental study of these shocks has been performed with the high energy density laser of the LULI, at the École Polytechnique (France). We have observed several shocks identified as radiative shocks. The shock waves propagate at about 50 km/s in a tiny 10 mm3 shock tube filled with gaz. From the measurements, it is possible to infer several features of the shock such as the speed and the electronic density.

Leygnac, S.; Lanz, T.; Stehlé, C.; Michaut, C.

2002-12-01

170

ENVIRONMENTAL RADIOACTIVITY LABORATORY INTERCOMPARISON STUDIES PROGRAM, 1978-1979  

EPA Science Inventory

The U.S. Environmental Protection Agency's intercomparison studies program for laboratories involved in environmental radiation measurements is described. The types of environmental samples distributed, the analyses required for each sample, the distribution schedule, and the sta...

171

ENVIRONMENTAL RADIOACTIVITY LABORATORY INTERCOMPARISON STUDIES PROGRAM, FY 1977  

EPA Science Inventory

The U.S. Environmental Protection Agency's intercomparison studies program for laboratories involved in environmental radiation measurements is described. The types of environmental samples distributed, the analysis required for each sample, the distribution schedule, and the sta...

172

21 CFR 58.130 - Conduct of a nonclinical laboratory study.  

Code of Federal Regulations, 2013 CFR

...false Conduct of a nonclinical laboratory study. 58.130 Section 58.130 Food...LABORATORY PRACTICE FOR NONCLINICAL LABORATORY STUDIES Protocol for and Conduct of a Nonclinical Laboratory Study § 58.130 Conduct of a...

2013-04-01

173

Detailed Laboratory Study of Asteroid Organics  

NASA Astrophysics Data System (ADS)

Until April 2010, organic molecules had not been detected on asteroids. They have now been identified on two objects: 24 Themis (Campins et al. 2010), (Rivkin and Emery 2010) and 65 Cybele (Licandro et al. 2011), and the organic absorptions on these objects appear different from each other. To better understand the nature of these organics and their differences we simulated four astronomical ice mixtures containing various ratios of aliphatic and aromatic hydrocarbons. Under ultra-high vacuum we took spectra of these ices in the near- and mid-infrared as we exposed the ices to UV radiation. After approximately 24 hours of UV exposure at a temperature of 15 K, we warmed the ices to 300 K with no UV irradiation. The gradual warming allowed the photoproducts produced by the UV irradiation to combine and react, creating various organics. Our initial results are promising. This study contributes to our understanding of the differences and similarities of the organic molecules that exist amongst the population of primitive asteroids, and may even help us to determine a parent body link to organic-rich meteorites.

Hargrove, Kelsey; Sandford, S.; Campins, H.

2013-10-01

174

Laboratory studies on the El Tor vibrio.  

PubMed

The identity of the El Tor vibrio is a controversial question that the usual methods of bacteriological investigation have as yet failed to settle. In this paper, the author presents the results of a study of the interrelationships between El Tor vibrios, true cholera vibrios and water vibrios, as revealed by the behaviour of the vibrios in the bile system and in the small intestine of experimental animals.The vibrios investigated included two strains isolated at the El Tor quarantine station on the Sinai Peninsula in 1934, two strains isolated at Makassar, Celebes, during a cholera epidemic in 1937 and identified as "El Tor" vibrios, four strains of true cholera vibrios and five strains of water vibrios. On the whole, the behaviour of the El Tor and Makassar vibrios was similar, closely resembling that of the cholera vibrios and differing markedly from that of the water vibrios. The author therefore considers that the strains of El Tor and Makassar vibrios examined are varieties of Vibrio cholerae and suggests that carriers of such strains should be subjected to the same measures as carriers of true cholera vibrios. PMID:13986981

SAYAMOV, R M

1963-01-01

175

Ammonia disinfection of animal feeds --laboratory study.  

PubMed

Animal feeds may be contaminated, accidentally or maliciously, with a number of zoonotic bacteria. Animal infections with these bacterial agents, whether or not they cause animal disease, may lead to human illnesses. Anhydrous ammonia was introduced on farms in developed countries as a high-nitrogen soil amendment, but later found use in enhancing crude protein in low-quality roughage fed to ruminants and in neutralizing mycotoxins in fungus-infested feed grains. Although ammonia has been known to be effective against bacteria in other contexts (e.g., manure, community sewage sludge, seeds for sprouting, and boneless lean beef trimmings), it appears that the antibacterial effect of ammoniating animal feeds had not been tested. In the present study, samples of roughage (wheat straw, corn silage) and concentrates (corn grain, cottonseed) produced as animal feed were contaminated with dried-on zoonotic bacteria (Salmonella Newport in all; Campylobacte jejuni, E. coli O157:H7, Listeria monocytogenes, Yersinia enterocolitica in corn grain only). Disinfection with anhydrous ammonia gas was conducted for 24 h at room temperature ( 25 degrees C). The treatment was least effective in silage because the silage alone showed strong antibacterial activity, which may have been slightly reduced by ammoniation. In the other three feeds, depending on the initial level of contamination, ammonia destruction of >or= 5 log10 cfu/g (99.999%) of the selected contaminant was usually observed. PMID:18155794

Tajkarimi, Mehrdad; Riemann, Hans P; Hajmeer, Maha N; Gomez, Edward L; Razavilar, Vadood; Cliver, Dean O

2007-11-21

176

Rodents as Sentinels for the Prevalence of Tick-Borne Encephalitis Virus  

PubMed Central

Abstract Introduction Tick-borne encephalitis virus (TBEV) causes one of the most important flavivirus infections of the central nervous system, affecting humans in Europe and Asia. It is mainly transmitted by the bite of an infected tick and circulates among them and their vertebrate hosts. Until now, TBE risk analysis in Germany has been based on the incidence of human cases. Because of an increasing vaccination rate, this approach might be misleading, especially in regions of low virus circulation. Method To test the suitability of rodents as a surrogate marker for virus spread, laboratory-bred Microtus arvalis voles were experimentally infected with TBEV and analyzed over a period of 100 days by real-time (RT)–quantitative polymerase chain reaction. Further, the prevalence of TBEV in rodents trapped in Brandenburg, a rural federal state in northeastern Germany with autochthonous TBE cases, was determined and compared with that in rodents from German TBE risk areas as well as TBE nonrisk areas. Results In experimentally infected M. arvalis voles, TBEV was detectable in different organs for at least 3 months and in blood for 1 month. Ten percent of all rodents investigated were positive for TBEV. However, in TBE risk areas, the infection rate was higher compared with that of areas with only single human cases or of nonrisk areas. TBEV was detected in six rodent species: Apodemus agrarius, Apodemus flavicollis, Apodemus sylvaticus, Microtus agrestis, Microtus arvalis, and Myodes glareolus. M. glareolus showed a high infection rate in all areas investigated. Discussion and Conclusion The infection experiments proved that TBEV can be reliably detected in infected M. arvalis voles. These voles developed a persistent TBE infection without clinical symptoms. Further, the study showed that rodents, especially M. glareolus, are promising sentinels particularly in areas of low TBEV circulation.

Ruzek, Daniel; Donoso-Mantke, Oliver; Schlegel, Mathias; Ali, Hanan Sheikh; Wenk, Mathias; Schmidt-Chanasit, Jonas; Ohlmeyer, Lutz; Ruhe, Ferdinand; Vor, Torsten; Kiffner, Christian; Kallies, Rene; Ulrich, Rainer G.; Niedrig, Matthias

2011-01-01

177

Soil type limits population abundance of rodents in crop fields: case study of the multimammate rat Mastomys natalensis Smith, 1834 in Tanzania.  

PubMed

Studies of populations of the multimammate rat Mastomys natalensis in Morogoro, Tanzania, show that soil texture appears to influence the population abundance and distribution of these rats in agricultural fields. The lowest rodent population abundance was found on sandy clay soils (F((2, 5)) = 8.42; P= 0.025). The population abundances of M. natalensis on sandy clay loam and sandy loam soils did not differ significantly (P? 0.05), possibly because these soils have a very similar texture. The results of this study suggest that M. natalensis prefers loam-textured soils with a high percentage of sand, which are probably better than clay soils for burrowing and nesting, particularly in the rainy season. The lower preference for clay soils is probably related to the poor aeration in these soils and the waterlogging that occurs during the wet season. PMID:21396048

Massawe, Apia W; Rwamugira, Winnie; Leirs, Herwig; Makundi, Rhodes H; Mulungu, Loth; Ngowo, V; Machang'u, Robert

2008-03-01

178

Glycosylphosphatidylinositols of Plasmodium chabaudi chabaudi: a basis for the study of malarial glycolipid toxins in a rodent model.  

PubMed Central

Free and protein-bound glycosylphosphatidylinositols (GPIs) of the blood stages of the rodent malarial parasite Plasmodium chabaudi chabaudi AS were identified and characterized. TLC analysis of material extracted by organic solvents from metabolically labelled parasites revealed a distinct set of glycolipids. These glycolipids were identified as GPIs by specific chemical and enzymic treatments and by structural analysis of their glycan and hydrophobic parts. These analyses revealed that P.c.chabaudi AS synthesizes a set of GPI-biosynthesis intermediates and two potential GPI-anchor precursors exhibiting the following structures: ethanolamine-phosphate [(alpha1-2)mannose]mannose (alpha 1-2) mannose (alpha 1-6) mannose (alpha 1-4) glucosamine - (acyl) inositol-phosphate-diacylglycerol (P.ch. alpha) and ethanolamine-phosphate - mannose (alpha 1-2) mannose (alpha 1-6) mannose (alpha 1-4) glucosamine-(acyl)inositol-phosphate-diacylglycerol (P.ch. beta). One of these GPI-anchor precursors (P.ch. alpha) possesses the same carbohydrate structure as the GPI membrane anchor of merozoite surface protein-1 from P.c.chabaudi AS.

Gerold, P; Vivas, L; Ogun, S A; Azzouz, N; Brown, K N; Holder, A A; Schwarz, R T

1997-01-01

179

Microevolution in island rodents  

Microsoft Academic Search

\\u000a We perform a meta-analysis on morphological data from four island rodent populations exhibiting microevolution (

Oliver R. W. Pergams; Mary V. Ashley

180

Microdialysis in Rodents  

PubMed Central

Microdialysis is an in vivo sampling technique that permits the quantification of various substances (e.g., neurotransmitters, peptides, electrolytes) in blood and tissue. It is also used to infuse substances into the brain and spinal cord. This unit describes methods for the construction and stereotaxic implantation of microdialysis probes into discrete brain regions of the rat and mouse. Procedures for the conduct of conventional and quantitative microdialysis experiments in the awake and anesthetized rodent are also provided.

Zapata, Agustin; Chefer, Vladimir I.; Shippenberg, Toni S.

2010-01-01

181

[Comparative ultrastructural study of the inner medullary zone of the kidney of rodents with varying water access in the habitat environment].  

PubMed

Studies have been made on the papillary zone of the kidney in wild rodents Microtus oeconomus, M. afganus, Nesokia indica and Rhombomus opimus, representing related taxonomic species but differing with respect to accessibility to water. In animals with high concentrating capacity, pronounced peculiarities of ultrastructure of descending and ascending parts of Henle's loop, thin epithelial layer in the collecting tubules and poor development of interstitial tissue account for higher level of water reabsorption. On the contrary, cytoplasmic ultrastructure of the collecting tubules in more arid species in simpler, this fact being presumably unrelated to the level of water reabsorption. Therefore, adaptation of the species investigated to the level of water accessibility is accompanied by ultrastructural changes in the inner medullary zone of the kidney. PMID:7043961

Getmanova, T N

182

Comparative Study of the Systems for Neutronics Calculations Used in Los Alamos Scientific Laboratory (LASL) And Argonne National Laboratory (ANL).  

National Technical Information Service (NTIS)

A comparative study of the systems for neutronics calculations used in Los Alamos Scientific Laboratory (LASL) and Argonne National Laboratory (ANL) has been performed using benchmark results available in the literature, in order to analyse the convenienc...

E. S. do Amorim A. B. D'Oliveira E. C. Oliveira

1980-01-01

183

The Study of Deceptive and Antisocial Behavior in the Laboratory.  

ERIC Educational Resources Information Center

|Research on crime and delinquents is generally studying norm-violating behavior outside of its social context. Building on Hartshorne and May's use of situational tests, the authors sought to study the major contributing variables to norm-violating behavior in a laboratory setting. Two groups of subjects were used: (1) 116 male college students;…

Brodsky, Stanley L.; Jacobsen, Linda S.

184

Geomagnetic field detection in rodents  

SciTech Connect

In addition to behavioral evidence for the detection of earth-strength magnetic fields (MF) by rodents, recent investigations have revealed that electrophysiological and biochemical responses to MF occur in the pineal organ and retina of rodents. In addition, ferrimagnetic deposits have been identified in the ethmoidal regions of the rodent skull. These findings point to a new sensory phenomenon, which interfaces with many fields of biology, including neuroscience, psychophysics, behavioral ecology, chronobiology and sensory physiology.

Olcese, J.; Reuss, S.; Semm, P.

1988-01-01

185

Laboratory diagnosis of rheumatoid arthritis. Prospective study of 85 patients  

Microsoft Academic Search

Because early diagnosis of rheumatoid arthritis is difficult increasingly important, we have assessed the value of laboratory investigation in 85 patients with knee effusions studied from presentation and followed for sufficiently long periods to allow a definite diagnosis. Histopathology on needle biopsy specimens narrowed the differential diagnosis to rheumatoid arthritis and closely related conditions even at an early stage of

C E Bayliss; R L Dawkins; G Cullity; R E Davis; J B Houliston

1975-01-01

186

Laboratory Scale Studies of SiHCl sub 3 Synthesis.  

National Technical Information Service (NTIS)

Laboratory scale preparation of SiHCl sub 3 was studied by chlorination of MG-Si with anhydrous hydrogen chloride gas in terms of the effects of temperature, HCl flow rate, silicon particle size, silicon packing height, catalyst and reaction time under 1 ...

T. L. Hwang H. H. Hsieh

1983-01-01

187

Ethnic Dislikes and Stereotypes: A Laboratory Study: Correction  

Microsoft Academic Search

Reports four errors in the article by Gregory Raran, Ethnic Dislikes and Stereotypes: A Laboratory Study (1950). Each error is described in detail. Face photographs of 30 college girls with ethnically nonspecific features were judged for General Liking, Beauty, Intelligence, Ambition, and Entertainingness by 150 male judges stratified to represent American adults. Two months later the judging was repeated, each

Gregory Razran

1950-01-01

188

Ecological validity of laboratory studies of videopoker gaming  

Microsoft Academic Search

This study compared the cognitive and behavioral components of videopoker players under laboratory and natural settings. Twenty regular gamblers (19 men and 1 woman) were matched into two groups on age and on frequency of gambling. Irrational verbalizations during gambling, monetary risk (number of bets doubled and number of tokens bet), and motivation served as dependent variables. Results showed no

Robert Ladouceur; Anne Gaboury; Annie Bujold; Nadine Lachance; Sarah Tremblay

1991-01-01

189

DESIGN AND EVALUATION OF LABORATORY ECOLOGICAL SYSTEM STUDIES  

EPA Science Inventory

Design and evaluation of laboratory ecological system studies are considered in relation to problems and objectives in environmental toxicology. Ecological systems are defined to be organismic systems together with their level-specific, co-extensive environmental systems and to o...

190

A laboratory study of Wilmington tar zone COâ injection project  

Microsoft Academic Search

A laboratory study of heavy oil recovery by COâ injection was undertaken in support of the Wilmington Tar Zone COâ Injection project operated by Long Beach Oil Development Company. The work included: - Phase behavior of Tar Zone reservoir oil and COâ. - Phase behavior of Tar Zone reservoir oil and the refinery gas (82% COâ - 18% Nâ) used

V. Sankur; J. L. Creek; S. S. DiJulio; A. S. Emanuel

1984-01-01

191

SEWER SEDIMENT GATE AND VACUUM FLUSHING TANKS: LABORATORY FLUME STUDIES  

EPA Science Inventory

The objective of this study was to test the performance of a traditional gate-flushing device and a newly designed vacuum-flushing device in removing sediments from combined sewers and CSO storage tanks. A laboratory hydraulic flune was used to simulate a reach of sewer or storag...

192

Laboratory Combustion Tube Studies. Part II. Report SUPRI TR-10.  

National Technical Information Service (NTIS)

To promote a better understanding of the problems and mechanisms involved in dry in-situ combustion of crude oils in porous media, continuing laboratory studies are carried out at SUPRI. The report about the first two experiments was submitted earlier to ...

W. E. Brigham M. R. Fassihi A. Satman R. L. Williams P. Pettit

1981-01-01

193

Laboratory study of biodegradation of lubricating oils in aquatic environments  

Microsoft Academic Search

A study on biodegradation of five different types of lubricating oils in aquatic environment has been completed in the laboratory and a methodology has been developed. The results show that the light oils were degraded readily; however, the removal rates were low. Up to 36% removal for the selected lubricating oils were achieved biologically after 70 days of operation. The

Xie Yongming; Sun Sien; Wang Zhenkui; Liu Xiufen; N. Biswas; J. K. Bewtra

1996-01-01

194

The Touchscreen Cognitive Testing Method for Rodents: How to Get the Best out of Your Rat  

ERIC Educational Resources Information Center

The touchscreen testing method for rodents is a computer-automated behavioral testing method that allows computer graphic stimuli to be presented to rodents and the rodents to respond to the computer screen via a nose-poke directly to the stimulus. The advantages of this method are numerous; however, a systematic study of the parameters that…

Bussey, Timothy J.; Padain, Tina L.; Skillings, Elizabeth A.; Winters, Boyer D.; Morton, A. Jennifer; Saksida, Lisa M.

2008-01-01

195

Distribution and ecological observations of wild rodents in Pampa de Achala, Córdoba, Argentina  

Microsoft Academic Search

This study lists the species of rodents living in the Pampa de Achala, a high plain in the Sierras de Córdoba, and analyses their habitat preferences and their Zoogeographic relationships. Five cricetine rodents in order of numbers captured were Akodon sp., Phyllotis darwinii, Oxymycterus paramensis, Reithrodon auritus, and Oligoryzomys flavescens, and one caviomorph rodent, Galea sp. Each of the seven

Jaime J. Polop

1989-01-01

196

Segmentation of Rodent Whole-Body Dynamic PET Images: An Unsupervised Method Based on Voxel Dynamics  

Microsoft Academic Search

Positron emission tomography (PET) is a useful tool for pharmacokinetics studies in rodents during the preclinical phase of drug and tracer development. However, rodent organs are small as compared to the scanner's intrinsic resolution and are affected by physiological movements. We present a new method for the segmentation of rodent whole-body PET images that takes these two difficulties into account

Renaud Maroy; Raphaël Boisgard; Claude Comtat; Vincent Frouin; Pascal Cathier; Edouard Duchesnay; Freédéric Dolle; Peter E. Nielsen; Régine Trébossen; Bertrand Tavitian

2008-01-01

197

Rodent carcinogens: Setting priorities  

SciTech Connect

The human diet contains an enormous background of natural chemicals, such as plant pesticides and the products of cooking, that have not been a focus of carcinogenicity testing. A broadened perspective that includes these natural chemicals is necessary. A comparison of possible hazards for 80 daily exposures to rodent carcinogens from a variety of sources is presented, using an index (HERP) that relates human exposure to carcinogenic potency in rodents. A similar ordering would be expected with the use of standard risk assessment methodology for the same human exposure values. Results indicate that, when viewed against the large background of naturally occurring carcinogens in typical portions of common foods, the residues of synthetic pesticides or environmental pollutants rank low. A similar result is obtained in a separate comparison of 32 average daily exposures to natural pesticides and synthetic pesticides residues in the diet. Although the findings do not indicate that these natural dietary carcinogens are important in human cancer, they cast doubt on the relative importance for human cancer of low-dose exposures to synthetic chemicals.

Gold, L.S.; Slone, T.H.; Stern, B.R.; Manley, N.B.; Ames, B.N. (Lawrence Berkeley lab., CA (United States))

1992-10-09

198

Rodent carcinogens: setting priorities.  

PubMed

The human diet contains an enormous background of natural chemicals, such as plant pesticides and the products of cooking, that have not been a focus of carcinogenicity testing. A broadened perspective that includes these natural chemicals is necessary. A comparison of possible hazards for 80 daily exposures to rodent carcinogens from a variety of sources is presented, using an index (HERP) that relates human exposure to carcinogenic potency in rodents. A similar ordering would be expected with the use of standard risk assessment methodology for the same human exposure values. Results indicate that, when viewed against the large background of naturally occurring carcinogens in typical portions of common foods, the residues of synthetic pesticides or environmental pollutants rank low. A similar result is obtained in a separate comparison of 32 average daily exposures to natural pesticides and synthetic pesticide residues in the diet. Although the findings do not indicate that these natural dietary carcinogens are important in human cancer, they cast doubt on the relative importance for human cancer of low-dose exposures to synthetic chemicals. PMID:1411524

Gold, L S; Slone, T H; Stern, B R; Manley, N B; Ames, B N

1992-10-01

199

Diet, caloric restriction, and the rodent bioassay.  

PubMed

The diet can significantly alter the results of toxicity and carcinogenicity studies. Ad libitum (AL) overfeeding of excessive calories to sedentary adult rodents is one of the most poorly controlled variables affecting the current rodent bioassay. AL-overfed rodents develop an early onset of adverse metabolic events, endocrine-disruptive degenerative diseases, and tumors that result in early morbidity and mortality. AL food consumption is extremely variable, but has a strong correlation with adult body weight, obesity, and survival. AL feeding of diets with modified protein, fiber, and energy content are not as effective as simple, moderate dietary (caloric) restriction (DR) in controlling these study variables. Moderate DR (70-75% of adult AL) is operationally simple and controls adult body weights, prevents obesity, and improves health and survival by reducing or delaying diet-related endocrine, renal, and cardiac diseases. Moderate DR provides a uniform rodent model, increases treatment exposure time, and increases the statistical sensitivity of these chronic bioassays to detect true treatment effects. Feeding a balanced diet by a moderate DR regimen of 70-75% of the maximum, unrestricted adult AL food intake is recommended for conducting well-controlled toxicity and carcinogenicity studies. PMID:10630587

Keenan, K P; Ballam, G C; Soper, K A; Laroque, P; Coleman, J B; Dixit, R

1999-12-01

200

A Practical Guide to Rodent Islet Isolation and Assessment  

PubMed Central

Pancreatic islets of Langerhans secrete hormones that are vital to the regulation of blood glucose and are, therefore, a key focus of diabetes research. Purifying viable and functional islets from the pancreas for study is an intricate process. This review highlights the key elements involved with mouse and rat islet isolation, including choices of collagenase, the collagenase digestion process, purification of islets using a density gradient, and islet culture conditions. In addition, this paper reviews commonly used techniques for assessing islet viability and function, including visual assessment, fluorescent markers of cell death, glucose-stimulated insulin secretion, and intracellular calcium measurements. A detailed protocol is also included that describes a common method for rodent islet isolation that our laboratory uses to obtain viable and functional mouse islets for in vitro study of islet function, beta-cell physiology, and in vivo rodent islet transplantation. The purpose of this review is to serve as a resource and foundation for successfully procuring and purifying high-quality islets for research purposes.

2009-01-01

201

Scatter-hoarding rodents prefer slightly astringent food.  

PubMed

The mutualistic interaction between scatter-hoarding rodents and their seed plants is highly complex yet poorly understood. Plants may benefit from the seed dispersal behavior of rodents, as long as seed consumption is minimized. In parallel, rodents may maximize foraging efficiency and cache high-quality resources for future consumption. Defensive compounds, such as tannins, are thought to be a major mechanism for plant control over rodent behavior. However, previous studies, using naturally occurring seeds, have not provided conclusive evidence supporting this hypothesis. Here, we test the importance of tannin concentrations on the scatter-hoarding behavior of rodents by using an artificial seed system. We combined feeding trials and field observations to examine the overall impact of seed tannin concentrations on rodent behavior and health. We found that rodents favored seeds with an intermediate amount of tannin (~5%) in the field. Meanwhile, in rodents that were fed a diet with different tannin content, only diets with high tannin content (25%, 15%, and 10%) caused a significant negative influence on rodent survival and health. Significant differences were not found among treatments with tannin levels of 0-5%. In contrast to many existing studies, our results clearly demonstrate that scatter-hoarding rodents prefer slightly 'astringent' food. In the co-evolutionary arms race between plants and animals, our results suggest that while tannins may play a significant role in reducing general predation levels by the faunal community, they have no precise control over the behavior of their mutualistic partner. Instead, the two partners appear to have reached an evolutionary point where both parties receive adequate benefits, with the year-to-year outcome being dependent on a wide range of factors beyond the control of either partner. PMID:22046284

Wang, Bo; Chen, Jin

2011-10-26

202

RESISTANCE OF AIRBORNE FUNGAL PROPAGULES TO ULTRAVIOLET IRRADIATION: LABORATORY STUDY  

Microsoft Academic Search

The inuence of ultraviolet (UV) radiation on fungi Aspergillus niger Tiegh. isolate OG168, Paecilomyces puntonii (Vuill.) Nann. isolate OG68, and Penicillium expansum Link isolate PO88 was studied under laboratory conditions. A test system was developed for this study. An aerosol chamber provided a dust-free space of 1.5 m3. The source of ultraviolet rays was an UV lamp (DPT 220, 240ñ320

V. Ulevi; D. Pe

203

Conjunctival lymphoid follicles in new world rodents.  

PubMed

We report for the first time, the detection of conjunctival lymphoid follicles (CLF) in the eyes of New World rodents. CLF were found in 7 of the 15 species examined, 6 of the 10 genera, and in at least one individual in four families of rodents. These follicles are dense collections of leukocytes in the conjunctival substantia propria with a thinned overlying epithelium lacking in goblet cells. Although the precise location of CLF within the conjunctiva varied from species to species, all CLF were found in the fornix of the conjunctival sac. In general, size and complexity of CLF varied with the size of the eye; the larger the eye, the larger and more complex the CLF. Our findings also reveal that some species of New World rodents, like the majority of Old World rodents examined in this and previous studies might lack CLF. However, until larger samples are examined, this is difficult to state with certainty. Consequently, the presence/absence of CLF at this point might not be informative for phylogenetic comparisons. Our findings also suggest the deer mouse, Peromyscus maniculatus, might serve as a useful model species for studying ocular infections and immunology of the eye. PMID:17722097

Astley, Roger A; Chodosh, James; Caire, William; Wilson, Gregory M

2007-09-01

204

Thirteen week rodent feeding study with grain from molecular stacked trait lepidopteran and coleopteran protected (DP-ØØ4114-3) maize.  

PubMed

The results from a subchronic feeding study conducted in Sprague–Dawley rats fed with diets containing grain from 4114 (OECD unique identifier: DP-ØØ4114-3) maize that was untreated (4114) or sprayed in field with glufosinate ammonium (4114GLU) in a design similar to previous studies are reported. The test material, 4114 maize, is a hybrid maize produced by transformation with a DNA construct encoding 4 different transgenic proteins for resistance to lepidopteran pests, coleopteran pests, and tolerance to the herbicidal active ingredient glufosinate ammonium. There were a total of 144 rats divided into 12 groups of 12 rats/sex/group. All experimental diets were formulated by Purina Mills, LLC (St. Louis, MO) in accordance with the standards of Purina Mills Labdiet® Certified Rodent LabDiet® 5002. The incorporation rate of maize grain in all diets was 32% (wt/wt). No biologically significant, treatment related differences in body weight, food consumption, clinical pathology parameters (hematology, blood chemistry, urinalysis, or organ weight) were observed in rats consuming the diets containing 4114 maize grain compared with rats fed conventional maize diets. A number of histologic observations were noted in this study but were background lesions and representative of what would be expected for rats of this age and strain. An independent panel of experts determined certain observations to be spontaneous and not related to the test diet. Accordingly, these results support the conclusion that 4114 maize grain is as safe and nutritious as conventional maize grain. PMID:23261672

Delaney, Bryan; Karaman, Sule; Roper, Jason; Hoban, Denise; Sykes, Greg; Mukerji, Pushkor; Frame, Steven R

2013-03-01

205

Roles of dental development and adaptation in rodent evolution.  

PubMed

In paleontology, many changes affecting morphology, such as tooth shape in mammals, are interpreted as ecological adaptations that reflect important selective events. Despite continuing studies, the identification of the genetic bases and key ecological drivers of specific mammalian dental morphologies remains elusive. Here we focus on the genetic and functional bases of stephanodonty, a pattern characterized by longitudinal crests on molars that arose in parallel during the diversification of murine rodents. We find that overexpression of Eda or Edar is sufficient to produce the longitudinal crests defining stephanodonty in transgenic laboratory mice. Whereas our dental microwear analyses show that stephanodonty likely represents an adaptation to highly fibrous diet, the initial and parallel appearance of stephanodonty may have been facilitated by developmental processes, without being necessarily under positive selection. This study demonstrates how combining development and function can help to evaluate adaptive scenarios in the evolution of new morphologies. PMID:24051719

Rodrigues, Helder Gomes; Renaud, Sabrina; Charles, Cyril; Le Poul, Yann; Solé, Floréal; Aguilar, Jean-Pierre; Michaux, Jacques; Tafforeau, Paul; Headon, Denis; Jernvall, Jukka; Viriot, Laurent

2013-09-20

206

Hemagglutination by Pasteurellaceae isolated from rodents.  

PubMed

Pasteurellaceae notably P. pneumotropica, have been associated with severe outbreaks of respiratory disease in several species of rodents. Host-specific parasitism of Pasteurellaceae in rodents has hardly been studied. Since host tropism in many bacteria involves adhesive mechanisms, we examined the hemagglutinating (HA) properties of 44 isolates from different rodent species (mouse (15) rat (8), hamster (9), gerbil (10) and Mastomys (2)). Only 13 mouse isolates and the 2 Mastomys isolates hemagglutinated human (type O Rh+) and canine red blood cells (RBCs). No HA was found using RBCs from 10 other animal species. HA was not inhibited by simple sugars and glycoconjugates, but was completely inhibited by heating of bacterial cells for 10 min at 80 or 100 degrees C, partially inhibited by glutaraldehyde and inhibited in a dose-dependent mode by NaIO4, suggesting the involvement of bacterial polysaccharide structures in the HA process. Enrichment procedures did not reveal the presence of HA- subpopulations in HA+ isolates or the presence of HA+ subpopulations in HA- isolates. Electron microscopy revealed the presence of fimbriae both in HA+ and HA- isolates. A regularly structured (RS) layer was detected on cells of part of the HA+ isolates only. Our results suggest that Pasteurellaceae of mice and Mastomys may be related and differ from isolates isolated from other rodent species. PMID:8219497

Boot, R; Thuis, H; Teppema, J S

1993-06-01

207

Laboratory and field studies on thin paint films  

Microsoft Academic Search

An account is presented of some aspects and results of a collaborative project currently being undertaken as part of the European Collaborative Action COST 520 programme in Working Group 3. The project involves the response of biocide- and non-biocide-containing thin paint films to microbial colonisation under laboratory and field conditions.From the results of exposure studies at four sites, two in

S. E. English; S. Fjelde; M. Greenhalgh; R. W. McCabe; T. McKenna; L. H. G. Morton; B. Schmidt; I. Sherrington

2003-01-01

208

Laboratory methods to study African swine fever virus.  

PubMed

We summarize findings of comparative studies in different cells cultures susceptible to ASFV infection, through the analysis of virus components and infectious virus particles production, as alternative means to grow field and laboratory ASFV strains. We also provide different methods to assay the infectivity of ASFV samples and to purify the infective virus particles. Finally we describe the general strategy to construct virus deletion mutants that can be engineered to obtain attenuated ASFV strains suitable for vaccine approaches. PMID:23041357

de León, Patricia; Bustos, María J; Carrascosa, Angel L

2012-10-03

209

Rorschach Measures of Aggression: A Laboratory-Based Validity Study  

Microsoft Academic Search

This study sought to complement the archival research designs that have established the empirical foundations of Rorschach aggression scores, including Exner's (2003) Aggressive Movement (AG) score and Meloy and Gacono's (1992) Aggressive Content (AgC), Aggressive Past (AgPast), and Aggressive Potential (AgPot) variables. Utilizing a highly controlled laboratory-based aggression paradigm and self-report measures of violence history in a sample of 35

Aaron J. Kivisto; Scott A. Swan

2012-01-01

210

Mycobiota and Ochratoxin A in laboratory mice feed: preliminary study  

Microsoft Academic Search

The occurrence of mycotoxin-producing moulds in animal feed is a hazard for animals. When these undesirable substances contaminate\\u000a laboratory animal feed, convey an additional problem in experimental animal assays confidence levels. The aim of this study\\u000a was to evaluate fungal contamination and to determine natural occurrence of Ochratoxin A (OTA) in 31 samples. OTA is a mycotoxin\\u000a produced by fungi

Inês Almeida; H. Marina Martins; Marta F. Marques; Salomé Magalhães; Fernando Bernardo

2010-01-01

211

Muon-induced Background Studies for Underground Laboratories  

Microsoft Academic Search

Muon-induced fast neutrons and long-lived radioactive isotopes in a detector and surrounding materials are important background sources for low-energy underground experiments. Detailed simulations of the muon flux and induced neutron background have been made for a variety of operating underground laboratories and overburden. Sensitivity to muon-induced backgrounds has been studied as a function of depth for selected detector geometries and

Dongming Mei; Andrew Hime; Mark Boulay; Steve Elliott

2004-01-01

212

Competition between two aquatic detritivorous isopods – a laboratory study  

Microsoft Academic Search

The role of adult faeces in juvenile nutrition of two isopod species, Proasellus coxalis s.l. and Asellus aquaticus (L.),\\u000a with similar trophic strategies and different reproductive output, has been studied in laboratory. Our aim was to consider\\u000a the possible competitive mechanisms occurring at the beginning of the species coexistence using allopatric populations in\\u000a single and mixed species experiments. Two series

M. Letizia Costantini; Loreto Rossi

1998-01-01

213

Laboratory reared sandflies (Diptera:Psychodidae) and studies on phleboviruses.  

PubMed

Virus-vector relationship of two Pleboviruses, Toscana and Arbia viruses, were studied in laboratory reared sandflies of the species Plebotomus perniciosus which is implicated as natural vector of both viruses. Two techniques of infection were used: intrathoracic inoculation and membrane feeding. This paper reports the growth characteristics and the frequency of transovarial and venereal transmission among P. perniciosus experimentally infected with the two viruses. PMID:1841201

Ciufolini, M G; Maroli, M; Verani, P

1991-12-01

214

Physical processes in cometary ices inferred from laboratory studies  

NASA Astrophysics Data System (ADS)

Based on recent laboratory studies, an overview is given of the properties of various ices and ice mixtures condensed at low temperatures, and on their evolution during heating up to temperatures typical of the perihelion temperatures of short period comets. The kinetics of formation and of decomposition of clathrate hydrates and molecular hydrates is outlined and the possibility of their occurrence in comet nuclei is discussed. Special attention is given to the thermal behavior of amorphous and fluffy icy material.

Klinger, J.

1989-12-01

215

Effect of prototypical inducers on ligand activated nuclear receptor regulated drug disposition genes in rodent hepatic and intestinal cells  

Microsoft Academic Search

Aim:The aim of this study was to investigate the impact on expression of mRNA and protein by paradigm inducers\\/activators of nuclear receptors and their target genes in rat hepatic and intestinal cells. Furthermore, assess marked inter laboratory conflicting reports regarding species and tissue differences in expression to gain further insight and rationalise previously observed species differences between rodent and human

Philip Martin; Robert Riley; Paul Thompson; Dominic Williams; David Back; Andrew Owen

2010-01-01

216

The management and breeding of some more hystricomorph rodents  

Microsoft Academic Search

SUMMARY The caging, feeding and handling in our laboratory of 4 unusual hystri- comorph rodents are described. These animals are: the wild guinea-pigs, or cuis (Cavia aperea and Galea musteloides), the degu (Octodon degus), and the plains viscacha (Lagostomus maximus). The species were obtained for investigation of their reproduction and some details of this are given.

Barbara J. Weir

1970-01-01

217

Laboratory study of microseismicity spreading due to pore pressure change  

NASA Astrophysics Data System (ADS)

Microseismicity variations in space and time due to pore pressure changes in an inhomogeneous permeable sample are considered. The analysis is based on laboratory experiments performed to study the relation between acoustic emission (which corresponds to microseismic events in real scale) and pore pressure changes due to water injection into, or release from, a porous sample under load. The study showed not only some characteristics of microseismicity variations during non-stationary fluid flow but also the possibility to solve the inverse problem of estimating local permeability from variations of microseismic activity in a particular volume of the porous medium.

Turuntaev, S. B.; Eremeeva, E. I.; Zenchenko, E. V.

2013-01-01

218

A Laboratory Study of Heterogeneity and Scaling in Geologic Media  

NASA Astrophysics Data System (ADS)

In rocks and soils, the bulk geophysical and transport properties of the matrix and of fracture systems are determined by the juxtaposition of geometric features at many length scales. For sedimentary materials the length scales are: the pore scale (irregularities in grain surface roughness and cementation), the scale of grain packing faults (and the resulting correlated porosity structures), the scale dominated by sorting or winnowing due to depositional processes, and the scale of geomorphology at the time of deposition. We are studying the heterogeneity and anisotropy in geometry, permeability, and geophysical response from the pore (microscopic), laboratory (mesoscopic), and backyard field (macroscopic) scales. In turn these data are being described and synthesized for development of mathematical models. Eventually, we will perform parameter studies to explore these models in the context of transport in the vadose and saturated zones. We have developed a multi-probe physical properties scanner which allows for the mapping of geophysical properties on a slabbed sample or core. This device allows for detailed study of heterogeneity at those length scales most difficult to quantify using standard field and laboratory practices. The measurement head consists of a variety of probes designed to make local measurements of various properties, including: gas permeability, acoustic velocities (compressional and shear), complex electrical impedance (4 electrode, wide frequency coverage), and ultrasonic reflection (ultrasonic impedance and permeability). We can thus routinely generate detailed geophysical maps of a particular sample. We are testing and modifying these probes as necessary for use on soil samples. As a baseline study we have been characterizing the heterogeneity of a bench-size Berea sandstone block. Berea Sandstone has long been regarded as a laboratory standard in rock properties studies, owing to its uniformity and ``typical'' physical properties. We find that both permeability and velocity exhibit complex heterogeneity at the centimeter scale. While some correlation with the outcropping of the bedding is apparent, much of the heterogeneity is not clearly associated with visual features. For the study of soil heterogeneity at a wide range of scales, we are focusing on a local glacial deposit. This deposit is a glacial kame terrace of fluvial origin with multi-scale sedimentary structures comprised of unconsolidated sands, clays, and gravels. There are also many joints and faults in the unconsolidated sediments, allowing study of these as potential fluid flow conduits or barriers. We have obtained undisturbed soil samples from this site, allowing detailed laboratory study using similar methods to those described for the sandstone block.

Brown, S.; Boitnott, G.; Bussod, G.; Hagan, P.

2004-05-01

219

A Laboratory Study of Heterogeneity and Scaling in Geologic Media  

NASA Astrophysics Data System (ADS)

In rocks and soils, the bulk geophysical and transport properties of the matrix and of fracture systems are determined by the juxtaposition of geometric features at many length scales. For sedimentary materials the length scales are: the pore scale (irregularities in grain surface roughness and cementation), the scale of grain packing faults (and the resulting correlated porosity structures), the scale dominated by sorting or winnowing due to depositional processes, and the scale of geomorphology at the time of deposition. We are studying the heterogeneity and anisotropy in geometry, permeability, and geophysical response from the pore (microscopic), laboratory (mesoscopic), and backyard field (macroscopic) scales. In turn these data are being described and synthesized for development of mathematical models. Eventually, we will perform parameter studies to explore these models in the context of transport in the vadose and saturated zones. We have developed a multi-probe physical properties scanner which allows for the mapping of geophysical properties on a slabbed sample or core. This device allows for detailed study of heterogeneity at those length scales most difficult to quantify using standard field and laboratory practices. The measurement head consists of a variety of probes designed to make local measurements of various properties, including: gas permeability, acoustic velocities (compressional and shear), complex electrical impedance (4 electrode, wide frequency coverage), and ultrasonic reflection (ultrasonic impedance and permeability). We can thus routinely generate detailed geophysical maps of a particular sample. With the exception of the acoustic velocity, we are testing and modifying these probes as necessary for use on soil samples. As a baseline study we have been characterizing the heterogeneity of a bench-size Berea sandstone block. Berea Sandstone has long been regarded as a laboratory standard in rock properties studies, owing to its uniformity and ``typical'' physical properties. We find that both permeability and velocity exhibit complex heterogeneity at the centimeter scale. While some correlation with the outcropping of the bedding is apparent, much of the heterogeneity is not clearly associated with visual features. For the study of soil heterogeneity at a wide range of scales, we are focusing on a local glacial deposit. This deposit is a glacial kame terrace of fluvial origin with multi-scale sedimentary structures comprised of unconsolidated sands, clays, and gravels. There are also many joints and faults in the unconsolidated sediments, allowing study of these as potential fluid flow conduits or barriers. We have obtained undisturbed soil samples from this site, allowing detailed laboratory study using similar methods to those described for the sandstone block.

Brown, S.; Boitnott, G.; Smith, M.

2003-12-01

220

Blood glucose concentration in caviomorph rodents  

Microsoft Academic Search

Hystricomorph rodents are a group of species that belong to the suborder Hystricognathi. They mainly inhabit South American (caviomorph) and African (phiomorph) habitats. This group of rodents has a divergent insulin structure. For example, insulin in this group of rodents exhibits only 1–10% of biological activity in comparison to other mammals. Therefore, hystricomorph rodents may hypothetically be unable to regulate

Juan C. Opazo; Mauricio Soto-Gamboa; Francisco Bozinovic

2004-01-01

221

Evaluation of the Adequacy of Published Studies of Low-Dose Effects of Bisphenol A on the Rodent Prostate for Use in Human Risk Assessment  

Microsoft Academic Search

Studies conducted in our laboratories and by others found no consistent correlation between prostate size, prostate pathology, or the development of prostate cancer under a variety of experimental conditions. Furthermore, an evaluation of eight published studies that were conducted in mice and rats following in utero exposure by oral treatment of dams with low levels of bisphenol A (BPA) and

Harry A. Milman; Maarten C. Bosland; Paul D. Walden; John E. Heinze

2002-01-01

222

Dual captures of Colorado rodents: implications for transmission of hantaviruses.  

PubMed Central

We analyzed dual-capture data collected during longitudinal studies monitoring transmission and persistence of Sin Nombre virus in rodents in Colorado. Our data indicate that multiple captures (two or more rodents captured in a single trap) may not be random, as indicated by previous studies, but rather the result of underlying, species-specific social behavior or cohesiveness. In the pairs we captured, most often, rodents were of the same species, were male, and could be recaptured as pairs. Therefore, dual captures of rodents, which are unusual but not rare, tend to occur among certain species, and appear to be nonrandom, group-foraging encounters. These demographic and ecologic characteristics may have implications for the study of the transmission of hantaviruses.

Calisher, C. H.; Childs, J. E.; Sweeney, W. P.; Canestrop, K. M.; Beaty, B. J.

2000-01-01

223

A Mechanistic Basis for the Beneficial Effects of Caloric Restriction On Longevity and Disease: Consequences for the Interpretation of Rodent Toxicity Studies  

Microsoft Academic Search

Caloric restriction in rodents has been repeatedly shown to increase life span while reducing the severity and retarding the onset of both spontaneous and chemically induced neoplasms. These effects of caloric restriction are associated with a spectrum of biochemical and physiological changes that characterize the organism's adaptation to reduced caloric intake and provide the mechanistic basis for caloric restriction's effect

Julian E. A. Leakey; John E. Seng; Crissy R. Barnas; Vanessa M. Baker; Ronald W. Hart

1998-01-01

224

Selection and validation of reference genes for real-time RT-PCR studies in the non-model species Delomys sublineatus, an endemic Brazilian rodent.  

PubMed

Quantitative real-time RT-PCR (qRT-PCR) is a sensitive technique for gene expression analysis. A critical factor for creating reliable data in relative quantification is the normalization of the expression data of genes of interest. Therefore the needed normalization factor is calculated out of the expression data of co-amplified genes that are stable expressed in the certain sample material, the so-called reference genes. In this study, we demonstrate the important process of validating potential reference genes using a non-model species. As there are almost no sequences known of the Pallid Atlantic Forest Rat (Delomys sublineatus), a rodent used as indicator species in conservation studies of the endangered Brazilian rainforest, suitable primer sets are more problematic to find than in model species. Out of nine tested primer sets designed for the fully sequenced Mus musculus, five could be used for the establishment of a proper running SYBR-Green assay and validation of their constant expression. qRT-PCR results of 12 cDNAs of Delomys livers were analyzed with three different validation software programs: BestKeeper, NormFinder and geNorm. Our approach showed that out of the five (Sdha, Canx, Pgk1, Actb and Actg1) potential reference genes, the first four should be used for accurate normalization in further relative quantification analyses. Transferring data from close-by model organisms makes high sensitive real-time RT-PCR applicable even to free-ranging non-model organisms. Our approach might be suitable for other non-model organisms. PMID:20059981

Weyrich, Alexandra; Axtner, Jan; Sommer, Simone

2010-01-06

225

Measuring rodent incisors from scats can increase accuracy of predator diet studies. An illustration based on island cats and rats  

Microsoft Academic Search

Non-invasive diet studies, which are a simple but important tool to understand trophic interactions inside ecosystems, need to be as detailed as possible. Determining the precise biomass of ingested prey is a key to obtaining not only a better understanding of the amount of food really ingested but also the predator-prey interactions. It is particularly relevant in the case of

Elsa Bonnaud; Eric Vidal; Diane Zarzoso-Lacoste; Franck Torre

2008-01-01

226

Health span extension by later-life caloric or dietary restriction: a view based on rodent studies  

Microsoft Academic Search

In spite of the potential benefit of lifelong food restriction to retard aging and extend life span, it is unrealistic in human. The restriction late in life may be more practical. There are, however, only limited studies on the effect of late onset caloric or dietary restriction. We and other investigators have shown that the late life restriction rejuvenates some

Sataro Goto

2006-01-01

227

Are the closed landfills recovered habitats for small rodents? A case study in a riparian site, Buenos Aires, Argentina  

Microsoft Academic Search

The establishment of landfills in urban areas leads to extensive disturbances. Their development after landfill closure depends\\u000a on the characteristics of the soil cover, the surrounding communities and the dispersal of plants and animals. This study\\u000a was carried out in a landfill closed in 2004, surrounded by an urban area, freshwater marshes and a riparian forest. The aim\\u000a of this

María Florencia Carballido; Pablo Arístide; María Busch; Emilio A. Cittadino; Isabel E. Gómez Villafañe

228

The safety of PolyGlycopleX® (PGX®) as shown in a 90-day rodent feeding study  

Microsoft Academic Search

BACKGROUND: This study was designed to evaluate the safety of PolyGlycopleX® (PGX®), a novel viscous dietary polysaccharide (fiber), when administered to Sprague Dawley® rats in the diet for 90 days. METHODS: Groups of ten male and ten female rats each consumed PGX mixed in the diet at levels of 0, 1.25, 2.5 or 5.0% for 90 days, then evaluated for

Ray A Matulka; Michael R Lyon; Simon Wood; Palma Ann Marone; Daniel J Merkel; George A Burdock

2009-01-01

229

Summary of an international methods validation study, carried out in nine laboratories, on the immunological assessment of cyclosporin A in the Fischer 344 rat.  

PubMed

In evaluating the adverse effects of chemicals on the immune response, the mouse has been the predominant animal species of choice. The acceptance of the mouse as a validated animal model has been the result, in part, of the studies conducted by the US National Toxicology Program (NTP). In these studies functional and host-resistance assays were developed and validated using five compounds and four testing laboratories. In toxicological evaluations of drugs and chemicals, the rat has been the rodent species of choice of the worldwide toxicology community. The current study was designed to begin the validation of the rat as a model for immunotoxicology assessment. Nine laboratories participated in the study, including laboratories from Canada, France, the United States and The Netherlands. Before the study began a detailed protocol was prepared and standard operating procedures were developed. Cyclosporin A was selected as the prototype immunosuppressive compound, and was administered orally to male Fischer 344 rats. Data were collected on standardized forms and submitted to a central laboratory for statistical analysis. Similar dose-response trends were observed between the various laboratories. In the natural killer cell assay and concanavalin A mitogen assay similar results were observed in at least 63% of the laboratories. In the T-dependent antibody-plaque forming cell assay, and the mixed leucocyte response, 100% of the laboratories that conducted the assays had statistically similar results. The results from this study support the usefulness of the rat as a model species for immunotoxicity assessment and represent a beginning for international interlaboratory validation of immunotoxicology assays in this species. PMID:20693053

White, K L; Gennings, C; Murray, M J; Dean, J H

1994-10-01

230

Neutrino Nuclear Responses for Neutrino Studies in Nuclear Femto Laboratories  

SciTech Connect

Fundamental properties of neutrinos and neutrino nuclear interactions are of great interest from particle and astro-nuclear physics view points. They are well studied in nuclear femto laboratories, where neutrino nuclear responses are crucial. Neutrino masses and neutrino natures are studied by neutrino-less double beta decays (0{nu}{beta}{beta}) in nuclei. Here neutrino nuclear responses are required to extract neutrino properties from 0{nu}{beta}{beta} rates. Neutrino nuclear responses are sensitive to nuclear spin isospin correlations and nuclear structures. They are experimentally studied by nuclear probes for charge exchange nuclear reactions, photon EM probes for photo-nuclear reactions, and lepton probes for muon and neutrino capture reactions.

Ejiri, Hiroyasu [Research Center for Nuclear Physics, Osaka University, Osaka 567-0047 (Japan); Nuclear Science, Czech Technical University, Brehova, Prague (Czech Republic)

2010-11-24

231

Laboratory combustion tube studies. Part II. Report SUPRI TR-10  

SciTech Connect

To promote a better understanding of the problems and mechanisms involved in dry in-situ combustion of crude oils in porous media, continuing laboratory studies are carried out at SUPRI. The report about the first two experiments was submitted earlier to the Department of Energy. This report describes the results of the last three tube runs. Three laboratory combustion tube studies were made with unconsolidated core material, and Lombardi Zone crude oil from the San Ardo field, California. After preparation, the material was packed into the combustion tube. Conditions employed during the steady burning phase of each run were about constant. Injection pressure for all of them was 100 Psig (6.8 Atm.). Burning front velocities ranged from 7.22 cm/hr (5.68 ft/day) to 12.96 cm/hr (10.2 ft/day) while the stream front velocities ranged from 10.4 cm/hr to 13.48 cm/hr. The air flux was between 88.33 SCF/hr-ft/sup 2/ and 122.7SCF/hr-ft/sup 2/. Observed fuel ration ranged from 162.54 SCF/lb to 169.33 SCF/lb of fuel burned. The detailed analysis of these experiments accompanied with their field application will be presented later.

Brigham, W.E.; Fassihi, M.R.; Satman, A.; Williams, R.L.; Pettit, P.; Grim, J.; Ramey, H.J. Jr.

1981-03-01

232

A study of divergent TA teaching styles in inquiry-based laboratory education  

Microsoft Academic Search

This dissertation is a study of the divergent behaviors evidenced by different TAs teaching inquiry based physics laboratories with minimal preparation on how to use techniques such as Socratic dialogue, wait time, and time management. The revised physics laboratory curricula, a four semester laboratory sequence, were studied over the course of two years and one of the laboratory manuals was

James H. Little

2006-01-01

233

Sleep-wake sensitive mechanisms of adenosine release in the basal forebrain of rodents: an in vitro study.  

PubMed

Adenosine acting in the basal forebrain is a key mediator of sleep homeostasis. Extracellular adenosine concentrations increase during wakefulness, especially during prolonged wakefulness and lead to increased sleep pressure and subsequent rebound sleep. The release of endogenous adenosine during the sleep-wake cycle has mainly been studied in vivo with microdialysis techniques. The biochemical changes that accompany sleep-wake status may be preserved in vitro. We have therefore used adenosine-sensitive biosensors in slices of the basal forebrain (BFB) to study both depolarization-evoked adenosine release and the steady state adenosine tone in rats, mice and hamsters. Adenosine release was evoked by high K(+), AMPA, NMDA and mGlu receptor agonists, but not by other transmitters associated with wakefulness such as orexin, histamine or neurotensin. Evoked and basal adenosine release in the BFB in vitro exhibited three key features: the magnitude of each varied systematically with the diurnal time at which the animal was sacrificed; sleep deprivation prior to sacrifice greatly increased both evoked adenosine release and the basal tone; and the enhancement of evoked adenosine release and basal tone resulting from sleep deprivation was reversed by the inducible nitric oxide synthase (iNOS) inhibitor, 1400 W. These data indicate that characteristics of adenosine release recorded in the BFB in vitro reflect those that have been linked in vivo to the homeostatic control of sleep. Our results provide methodologically independent support for a key role for induction of iNOS as a trigger for enhanced adenosine release following sleep deprivation and suggest that this induction may constitute a biochemical memory of this state. PMID:23326515

Sims, Robert Edward; Wu, Houdini Ho Tin; Dale, Nicholas

2013-01-11

234

Sleep-Wake Sensitive Mechanisms of Adenosine Release in the Basal Forebrain of Rodents: An In Vitro Study  

PubMed Central

Adenosine acting in the basal forebrain is a key mediator of sleep homeostasis. Extracellular adenosine concentrations increase during wakefulness, especially during prolonged wakefulness and lead to increased sleep pressure and subsequent rebound sleep. The release of endogenous adenosine during the sleep-wake cycle has mainly been studied in vivo with microdialysis techniques. The biochemical changes that accompany sleep-wake status may be preserved in vitro. We have therefore used adenosine-sensitive biosensors in slices of the basal forebrain (BFB) to study both depolarization-evoked adenosine release and the steady state adenosine tone in rats, mice and hamsters. Adenosine release was evoked by high K+, AMPA, NMDA and mGlu receptor agonists, but not by other transmitters associated with wakefulness such as orexin, histamine or neurotensin. Evoked and basal adenosine release in the BFB in vitro exhibited three key features: the magnitude of each varied systematically with the diurnal time at which the animal was sacrificed; sleep deprivation prior to sacrifice greatly increased both evoked adenosine release and the basal tone; and the enhancement of evoked adenosine release and basal tone resulting from sleep deprivation was reversed by the inducible nitric oxide synthase (iNOS) inhibitor, 1400 W. These data indicate that characteristics of adenosine release recorded in the BFB in vitro reflect those that have been linked in vivo to the homeostatic control of sleep. Our results provide methodologically independent support for a key role for induction of iNOS as a trigger for enhanced adenosine release following sleep deprivation and suggest that this induction may constitute a biochemical memory of this state.

Sims, Robert Edward; Wu, Houdini Ho Tin; Dale, Nicholas

2013-01-01

235

Chronotype changes during puberty depend on gonadal hormones in the slow-developing rodent, Octodon degus.  

PubMed

During puberty, human adolescents develop a later chronotype, exhibiting a delay in the timing of rest and activity as well as other daily physiological rhythms. The purpose of this study was to determine whether similar changes in chronotype occur during puberty in a laboratory rodent species, and, if so, to determine whether they are due to pubertal hormones acting on the circadian timekeeping system. To test this hypothesis, we carefully tracked daily activity rhythms across puberty in the slow-developing rodent Octodon degus. We confirmed that male degus showed a large reorganization of activity rhythms that correlated with secondary sex development during puberty, including a loss of bimodality and a 3-5 h phase-advance. Similar to humans, this circadian reorganization showed distinct sex differences, with females showing little change during puberty in two separate experiments. Prepubertal gonadectomy (GDX) eliminated the changes, whereas SHAM gonadectomy had little impact. Therefore, gonadal hormones are likely to play a role in pubertal changes in chronotype in this rodent species. Using evidence from a variety of species, including our recent studies in the rat, we conclude that chronotype changes during puberty are a well-demonstrated phenomenon in mammals. PMID:21316365

Hagenauer, Megan Hastings; Ku, Jennifer HeeYoung; Lee, Theresa M

2011-02-18

236

Bone tissue reaction to Ti-48Al-2Cr-2Nb (at.%) in a rodent model: a preliminary SEM study.  

PubMed

A variety of metals have been used to replace the skeletal framework of human beings. Gamma titanium aluminide (gammaTiAl) has been recently developed as a prospective material for turbine applications. In this preliminary study, the potential of gammaTiAl as a biomaterial was evaluated using an in vivo rat model. Sprague-Dawley rats were implanted with gammaTiAl cylinders in the femur and observed for an experimental period lasting up to 180 days. The rats were sacrificed after periods of 45, 90 and 180 days. The femurs with the gammaTiAl implants were extracted and examined using scanning electron microscopy (SEM). Normal bone growth processes were observed as early as 45 days after gammaTiAl cylinder implantation. No signs of rejection of the implant metal were observed. In fact, a layered bone growth was observed on the implant metal surface. The bone-metal interface showed signs of tissue growth from original bone to the metal surface. gammaTiAl appears to elicit a normal bone tissue reaction and hence, has potential as a metallic implant material. PMID:17387593

Castañeda-Muñoz, Diego F; Sundaram, Paul Antony; Ramírez, Norman

2007-03-27

237

Structure and function of cytosolic glucocorticoid receptors in rodent lymphoid cells: studies of receptor stability, subunit composition, and phosphorylation  

SciTech Connect

The primary goal of these studies was to determine whether the cytosolic glucocorticoid receptor is dephosphorylated during the activation process in the intact cell. To address this question cytosolic complexes were purified from cells grown in medium containing (/sup 32/P)orthophosphoric acid or (/sup 32/S)methionine to allow quantitation of the number of phosphates and the amount of receptor protein, respectively. Steroid-binding proteins were identified by their specific association with the affinity label (/sup 3/H)dexamethasone 21-mesylate (DM). Attempts to purify nonactivated glucocorticoid-receptor complexes from rat thymocyte cytosol were unsuccessful due to the activity of an endogenous leupeptin-sensitive, calcium-activated protease which degraded the receptor to a form which was not recognized by the antibody. Nonactivated cytosolic complexes purified from WEHI-7 mouse thymoma cells using the BuGR1 monoclonal antibody contained a 90 kilodalton (90 kDa) non-steroid-binding subunit which could be separated from the 100 kDa steroid-binding subunit by SDS-PAGE. From these results the authors conclude that the nonactivated complex is a heteromeric structure which dissociates upon activation, and that activation of the complex in the intact cell does not result in a dephosphorylation of the 100 kDa steroid-binding protein.

Mendel, D.B.

1986-01-01

238

Rodent models of TDP-43: Recent advances  

PubMed Central

Recently, missense mutations in the gene TARDBP encoding TDP-43 have been linked to familial ALS. The discovery of genes encoding these RNA binding proteins, such as TDP-43 and FUS/TLS, raised the notion that altered RNA metabolism is a major factor underlying the pathogenesis of ALS. To begin to unravel how mutations in TDP-43 cause dysfunction and death of motor neurons, investigators have employed both gain- and loss-of-function studies in rodent model systems. Here, we will summarize major findings from the initial sets of TDP-43 transgenic and knockout rodent models, identify their limitations, and point to future directions toward clarification of disease mechanism(s) and testing of therapeutic strategies that ultimately may lead to novel therapy for this devastating disease.

Tsao, William; Jeong, Yun Ha; Lin, Sophie; Ling, Jonathan; Price, Donald L.; Chiang, Po-Min; Wong, Philip C.

2013-01-01

239

Laboratory exposure to Brucella melitensis in Denmark: a prospective study.  

PubMed

Brucella species are a frequent cause of laboratory-acquired infections. This report describes the handling of a laboratory exposure of 17 laboratory staff members exposed to Brucella melitensis in a large microbiology laboratory in a brucella-non-endemic area. We followed the US Centers for Disease Control and Prevention guidelines, but, of 14 staff members classified as high-risk exposure, none accepted post-exposure prophylaxis. However, in a period of 6 months of follow-up, none of the exposed laboratory workers developed brucellosis and all obtained sera were negative for antibrucella antibodies. We therefore question the value of routine serological follow-up. PMID:24070633

Knudsen, A; Kronborg, G; Dahl Knudsen, J; Lebech, A-M

2013-09-08

240

Systematic studies of Oryzomyine rodents (Muridae, Sigmodontinae): diagnoses and distributions of species formerly assigned to Oryzomys 'capito'  

USGS Publications Warehouse

We describe the morphological species-boundaries and geographic distributions of ten Neotropical Oryzomys based on analyses of museum specimens (skins and skulls, examples preserved in fluid, chromosomal spreads, and information about collection sites from skin tags, field catalogs, and other sources). These species have been regarded as members of an Oryzomys capito complex and for a long time were consolidated into a single entity identified as O. capito. Our study documents the following: 1. Defining the limits of species within the O. capito complex first requires a comprehensive review and rigorous definition of O. capito itself. We consider Fischer's (1814) Mus megacephalus to be valid and available, designate a neotype to bear the name, and reinstate it as a senior synonym of capito Olfers (1818). We then provide a working definition of O. megacephalus and its close relative, O. laticeps, derived from analyses of morphometric variation, estimates of geographic distributions, and evaluations of synonyms. In our view, O. megacephalus occurs in Amazonia but also extends into eastern Paraguay; its synonyms are capito Olfers (1818), cephalotes Desmarest (1819), velutinus Allen and Chapman (1893), goeldi Thomas (1897), modestus Allen (1899), and perenensis Allen (1901). Oryzomys laticeps Lund (1840) occurs in the Atlantic Forest region of eastern Brazil. We designate a lectotype for laticeps and allocate the names saltator Winge (1887) and oniscus Thomas (1904) as synonyms. 2. We provide the first comprehensive taxonomic revision of Oryzomys yunganus Thomas (1902). Its range covers tropical evergreen rainforest formations in the Guiana region and the Amazon Basin where, as documented by voucher specimens, it has been collected at the same localities as O. megacephalus, O. nitidus, and O. tern of carotid arterial circulation, occlusal patterns of second upper and lower molars, cranial proportions, and chromosomal features. Appreciable intraspecific geographic variation occurs in diploid number of chromosomes and frequency of occurrence of the hypothenar plantar pad, but sampling inadequacies obscure the significance of this variation. Large body size is characteristic of populations in the western Amazon Basin and in the tepui region of eastern Venezuela; smaller size characterizes populations in the Guianas and along the eastern margin of the Amazon Basin. No other scientific name has been correctly associated with the species. Samples from Mirador, Palmera, and Mera in the western Andean foothills of central Ecuador possess a combination of pelage, cranial, and dental traits that distinguish them from all samples of O. yunganus. These specimens are the basis for a new species we describe here, one that is more closely related to O. yunganus than to any other member of the former O. 'capito' complex. 3. We redescribe Oryzomys bolivaris (reviewed by Pine, 1971, under the name O. bombycinus), amplify its geographic range, and contrast it with O. talamancae and O. alfaroi, two sympatric congeners often confused with it. A distinctive set of morphological traits allows unambiguous identification of specimens belonging to O. bolivaris. It is a trans-Andean species recorded from very wet tropical evergreen rainforests extending from eastern Honduras and Nicaragua through Costa Rica and Panama to western Colombia and Ecuador. Allen's (1901) bolivaris is the oldest name for this species; castaneus Allen (1901), rivularis Allen (1901), bombycinus Goldman (1912), alleni Goldman (1915), and orinus Pearson (1939) are synonyms. 4. We revise the definition of Oryzomys talamancae Allen (1891) provided by Musser and Williams (1985), document additional specimens, describe karyotypes from Ecuadoran and Venezuelan samples, and contrast its morphology, chromosomes, and distribution with those of O. alfaroi and O. megacephalus. The geographic distribution of O. talamancae is also trans-Andean, but it inh

Musser, G.G.; Carleton, M.D; Brothers, E.M.; Gardner, A.L.

1998-01-01

241

Feasibility study of medical isotope production at Sandia National Laboratories  

SciTech Connect

In late 1994, Sandia National Laboratories in Albuquerque, New Mexico, (SNL/NM), was instructed by the Department of Energy (DOE) Isotope Production and Distribution Program (IPDP) to examine the feasibility of producing medically useful radioisotopes using the Annular Core Research Reactor (ACRR) and the Hot Cell Facility (HCF). Los Alamos National Laboratory (LANL) would be expected to supply the targets to be irradiated in the ACRR. The intent of DOE would be to provide a capability to satisfy the North American health care system demand for {sup 99}Mo, the parent of {sup 99m}Tc, in the event of an interruption in the current Canadian supply. {sup 99m}Tc is used in 70 to 80% of all nuclear medicine procedures in the US. The goal of the SNL/NM study effort is to determine the physical plant capability, infrastructure, and staffing necessary to meet the North American need for {sup 99}Mo and to identify and examine all issues with potential for environmental impact.

Massey, C.D.; Miller, D.L.; Carson, S.D. [Sandia National Labs., Albuquerque, NM (United States). Environmental Regulatory Assessment Dept.] [and others

1995-12-01

242

Anterior chamber lenses. Part II: A laboratory study.  

PubMed

An analysis of 606 surgically removed anterior chamber intraocular lens (IOL) specimens revealed that 351 or 58% of these were small-diameter, round loop, closed-loop styles. Because of the extremely high percentage of IOLs with this design received in our laboratory and the correlation of clinical histories with our histopathologic findings, we have concluded that such IOLs do not provide the safety and efficacy achieved by other anterior chamber lens designs. The finely polished, one-piece, all-PMMA styles fared well in our study. Although these one-piece styles comprise well over 50% of the American market share of anterior chamber IOLs, they comprise only 14% of all anterior chamber IOLs accessioned in our laboratory, compared to 58% for closed-loop designs. We believe that implantation of anterior chamber lenses with small-diameter, round, closed loops is no longer warranted. Patients in whom these IOLs have already been implanted should be carefully followed. It is our opinion that the FDA should recall or closely monitor all IOLs of this design and that implantation of closed-loop lenses should be discontinued in the United States. Furthermore, we believe that an IOL deemed to be not medically sound or worthy of implantation in the United States should not be marketed or donated outside of this country. PMID:3572773

Apple, D J; Hansen, S O; Richards, S C; Ellis, G W; Kavka-Van Norman, D; Tetz, M R; Pfeffer, B R; Park, R B; Crandall, A S; Olson, R J

1987-03-01

243

Tracking genome organization in rodents by Zoo-FISH.  

PubMed

The number of rodent species examined by modern comparative genomic approaches, particularly chromosome painting, is limited. The use of human whole-chromosome painting probes to detect regions of homology in the karyotypes of the rodent index species, the mouse and rat, has been hindered by the highly rearranged nature of their genomes. In contrast, recent studies have demonstrated that non-murid rodents display more conserved genomes, underscoring their suitability for comparative genomic and higher-order systematic studies. Here we provide the first comparative chromosome maps between human and representative rodents of three major rodent lineages Castoridae, Pedetidae and Dipodidae. A comprehensive analysis of these data and those published for Sciuridae show (1) that Castoridae, Pedetidae and Dipodidae form a monophyletic group, and (2) that the European beaver Castor fiber (Castoridae) and the birch mouse Sicista betulina (Dipodidae) are sister species to the exclusion of the springhare Pedetes capensis (Pedetidae), thus resolving an enduring trifurcation in rodent higher-level systematics. Our results together with published data on the Sciuridae allow the formulation of a putative rodent ancestral karyotype (2n = 50) that is thought to comprise the following 26 human chromosomal segments and/or segmental associations: HSA1pq, 1q/10p, 2pq, 2q, 3a, 3b/19p, 3c/21, 4b, 5, 6, 7a, 7b/16p, 8p/4a/8p, 8q, 9/11, 10q, 12a/22a, 12b/22b, 13, 14/15, 16q/19q, 17, 18, 20, X and Y. These findings provide insights into the likely composition of the ancestral rodent karyotype and an improved understanding of placental genome evolution. PMID:18266061

Graphodatsky, Alexander S; Yang, Fengtang; Dobigny, Gauthier; Romanenko, Svetlana A; Biltueva, Larisa S; Perelman, Polina L; Beklemisheva, Violetta R; Alkalaeva, Elena Z; Serdukova, Natalya A; Ferguson-Smith, Malcolm A; Murphy, William J; Robinson, Terence J

2008-02-11

244

Laboratory studies of homogeneous nucleation of iodine oxides  

NASA Astrophysics Data System (ADS)

The impact of "new" particle formation in the troposphere on climate, both regional and global, is of great interest. Recent field studies have pointed out possible new particle formation resulting from iodine chemistry in the marine environment. The particle formation mechanism has not been clearly identified but correlation with both solar flux and low tide has lead to the proposal that alkyl iodides (particularly CH_2I_2) are precursors for new particle formation. Hoffman et al. [2001] have proposed OIO to be the nucleating molecule. Jimenez et al. [2002] have since performed laboratory experiments in a large volume reaction chamber to study the iodine oxide particle formation. In this work, we have extended the laboratory measurements of the iodine oxide nucleation system using a 70 L Teflon bag reactor to better define the initial steps in the nucleation process. A nucleation model is presented and used to interpret the experimental observations and derive thermodynamic parameters, which are applicable for atmospheric models of homogeneous nucleation of OIO. Using this nucleation model, the atmospheric implications of the iodine oxide nucleation are examined using box model calculations. References: Hoffman, T., C.D. O'Dowd, and J.H. Seinfeld, Iodine oxide homogeneous nucleation: An explanation for coastal new particle production, Geophys. Res. Lett., 28, 1949--1952, 2001. Jimenez, J.J., D.R. Cocker, R. Bahreini, H. Zhuang, V. Varutbangkul, R.C. Flagan, and J.H. Seinfeld, New particle formation from photooxidation of diiodomethane (CH_2I_2), J. Geophys. Res. submitted 2002.

Burkholder, J.; Curtius, J.; Ravishankara, A.; Lovejoy, E.

2003-04-01

245

Challenges in Using Cultured Primary Rodent Hepatocytes or Cell Lines to Study Hepatic HDL Receptor SR-BI Regulation by Its Cytoplasmic Adaptor PDZK1  

PubMed Central

Background PDZK1 is a four PDZ-domain containing cytoplasmic protein that binds to a variety of membrane proteins via their C-termini and can influence the abundance, localization and/or function of its target proteins. One of these targets in hepatocytes in vivo is the HDL receptor SR-BI. Normal hepatic expression of SR-BI protein requires PDZK1 - <5% of normal hepatic SR-BI is seen in the livers of PDZK1 knockout mice. Progress has been made in identifying features of PDZK1 required to control hepatic SR-BI in vivo using hepatic expression of wild-type and mutant forms of PDZK1 in wild-type and PDZK1 KO transgenic mice. Such in vivo studies are time consuming and expensive, and cannot readily be used to explore many features of the underlying molecular and cellular mechanisms. Methodology/Principal Findings Here we have explored the potential to use either primary rodent hepatocytes in culture using 2D collagen gels with newly developed optimized conditions or PDZK1/SR-BI co-transfected cultured cell lines (COS, HEK293) for such studies. SR-BI and PDZK1 protein and mRNA expression levels fell rapidly in primary hepatocyte cultures, indicating this system does not adequately mimic hepatocytes in vivo for analysis of the PDZK1 dependence of SR-BI. Although PDZK1 did alter SR-BI protein expression in the cell lines, its influence was independent of SR-BI’s C-terminus, and thus is not likely to occur via the same mechanism as that which occurs in hepatocytes in vivo. Conclusions/Significance Caution must be exercised in using primary hepatocytes or cultured cell lines when studying the mechanism underlying the regulation of hepatic SR-BI by PDZK1. It may be possible to use SR-BI and PDZK1 expression as sensitive markers for the in vivo-like state of hepatocytes to further improve primary hepatocyte cell culture conditions.

Tsukamoto, Kosuke; Buck, Lorenna; Inman, Walker; Griffith, Linda; Kocher, Olivier; Krieger, Monty

2013-01-01

246

METABOLIC AND THERMOREGULATORY RESPONSES OF THE RAT MAINTAINED IN ACRYLIC OR WIRE-SCREEN CAGES: IMPLICATIONS FOR PHARMACOLOGICAL STUDIES  

EPA Science Inventory

Laboratory rodents are usually housed and studied in cages with walls and floor made of ventilated metal or solid plastic materials. It should be recognized that a rodent's thermoregulatory requirements will vary in metal and plastic cages; and it is likely that its metabolic res...

247

Basal rate of metabolism and temperature regulation of two desert herbivorous octodontid rodents: Octomys mimax and Tympanoctomys barrerae  

Microsoft Academic Search

We studied the energetics of two herbivorous desert rodents from South America. The two species had slightly lower basal metabolic rates, lower thermal conductances, and higher temperature differentials than those expected from their body mass. Mass-independent basal rates of metabolism were higher than those reported for seed-eating desert rodents from North America. Our observations support the hypothesis that desert rodents

Francisco Bozinovic; Luis C. Contreras

1990-01-01

248

Partnering at the National Laboratories: Catalysis as a Case Study  

SciTech Connect

The role of the national laboratories, particularly the defense program laboratories, since the end of the cold war, has been a topic of continuing debate. The relationship of national laboratories to industry spurred debate which ranged from designating the labs as instrumental to maintaining U.S. economic competitiveness to concern over the perception of corporate welfare to questions regarding the industrial globalization and the possibility of U.S. taxpayer dollars supporting foreign entities. Less debated, but equally important, has been the national laboratories' potential competition with academia for federal research dollars and discussions detailing the role of each in the national research enterprise.

JACKSON,NANCY B.

1999-09-14

249

Qualitative and quantitative study on drainage networks at laboratory scale  

NASA Astrophysics Data System (ADS)

Although simulated drainage networks at the laboratory scale would represent highly-simplified models of natural drainages, they would provide a significant contribute to the comprehension of the complex dynamics governing the fluvial systems. Laboratory experiments also give the advantage to detect transient growth phases shedding some light on the knowledge of temporal and spatial landform evolution. Perhaps, pioneering laboratory experiments on drainage network evolution were carried out in 1977 at REF (Rainfall Erosion Facility) of Colorado State University by Schumm and co-workers. This study deals with an analysis of physical experiments simulating the evolution and the development of drainage networks. To this purpose, some experiments were carried out at University of Basilicata by using a 1.5 m by 1.5 m box-basin-simulator with an outlet incised in the middle of the downslope-end side. The experimental landscape was made of a weakly cohesive soil mainly constituted by clay and silt. A system of microsprinklers generated an almost uniform artificial precipitation. Simulations were performed at a constant rainfall rate with intensity of 100 mm/h. In total four experiments were carried out. Three of those were conducted by ensuring consistent initial conditions except for the initial landscape planar slope of 9%, 5%, and 0.6%, respectively. The remaining experiment was performed with a landscape slope of 9% again, but with the (surface) base-level coinciding with the base of the outlet (i.e. streams could not erode below the base-level). Despite the central outlet constraint, the generated stream system for the 9% plane exhibited trellis-like drainage patterns with many short tributaries joining the main stream at nearly right angles. For the 5% experiment still sub-parallel drainage patterns were formed but mainly in the centre of the watershed. Channels were clearly shallower than those of the 9% experiment. For the gentler slope of 0.6% dendritic drainage patterns developed with tributaries entering the main channel at acute angles (less than 90Ë? ). Digital elevation models (DEM) of the evolving landscape were achieved through detailed soil surveys with a laser pointer or a laser scanner. Then, the drainage networks were extracted from the DEMs by using the D8 algorithm. Based on the data collected, the scaling properties of the simulated networks are analysed and compared with those of natural basins. Findings are provided mainly in terms of Hortonian laws, fractal dimensions and informational entropy. Scaling properties and space filling tendencies are discussed and peculiar differences between quasi-equilibrium and transient stages are also highlighted. Experimental evidences are also provided on the interaction between the base-level and growing mechanisms.

Oliveto, G.; Palma, D.; di Domenico, A.

2009-04-01

250

Laboratory Studies of Supersonic Magnetized Plasma Jets and Radiative Shocks  

NASA Astrophysics Data System (ADS)

In this talk I will focus on laboratory plasma experiments producing magnetically driven supersonic plasma jets and on the interaction of these jets with ambient media. The experiments are scalable to astrophysical flows in that the critical dimensionless numbers such as the plasma collisionality, the plasma beta, the Reynolds number and the magnetic Reynolds number are all in the astrophysically appropriate ranges. The experimental results will be compared with computer simulations performed with laboratory plasma codes and with astrophysical codes. In the experiments the jets are driven and collimated by the toroidal magnetic fields and it is found that the level of MHD instabilities in the jets strongly depends on the strength of the field represented by the ratio of the thermal to magnetic field pressures (plasma beta). The experiments show the possibility of formation of episodic outflows, with periodic ejections of magnetic bubbles naturally evolving into a heterogeneous jet propagating inside a channel made of self-collimated magnetic cavities [1,2]. We also found that it is possible to form quasi-laminar jets which are “indirectly” collimated by the toroidal magnetic fields, but this requires the presence of the lower density halo plasma surrounding the central jet [3]. Studies of the radiative shocks formed in the interaction of the supersonic magnetized plasma flows with ambient plasma will be also presented, and the development of cooling instabilities in the post-shock plasma will be discussed. This research was sponsored by EPSRC Grant No. EP/G001324/1 and by the OFES DOE under DOE Cooperative Agreement No. DE-SC-0001063. References 1. A. Ciardi, S.V. Lebedev, A. Frank et al., The Astrophysical Journal, 691: L147-L150 (2009) 2. F.A. Suzuki-Vidal, S.V. Lebedev, S.N. Bland et al., Physics of Plasmas, 17, 112708 (2010). 3. F.A. Suzuki-Vidal, M. Bocchi, S.V. Lebedev et al., Physics of Plasmas, 19, 022708 (2012).

Lebedev, Sergey

2013-06-01

251

Microbial colonization of retorted shale in field and laboratory studies  

SciTech Connect

The microbial colonization of retorted shale was measured in field lysimeters and laboratory with retorted shale obtained from an above-ground retort operating in the direct heating mode. In field lysimeter studies, total aerobic heterotrophic bacterial colony forming units (cfu), as measured by a selective plating medium in surface horizons of retorted shale and adjacent soils, were similar (3.3 x 10/sup 6/ and 2.7 x 10/sup 6/ bacterial cfu/g dry weight) two months after disposal. However, unlike the soil that exhibited a diverse community, the retorted shale was dominated by a single Micrococcus species that composed 30% of the total bacterial community. After one and two years, the total aerobic heterotrophic bacterial cfu in the retorted shale and soil were again similar; however, no bacterium dominated either community. A core sample from the field lysimeter indicated microbial colonization to a depth of 150 cm after one year. An increased ratio of anaerobic to aerobic heterotrophic bacterial cfu in the deepest sample (120 to 150 cm) implied the development of anaerobic conditions. In the laboratory, aerobic heterotrophic bacteria were shown capable of using, as the sole source of carbon, retorted shale in liquid cultures. Of the added nutritional amendments, PO/sub 4//sup -3/, NO/sub 3//sup -/ and SO/sub 4//sup -2/, only phosphate markedly altered the colonization of retorted shale in liquid culture; shortening the lag phase of colonization from less than three to seven weeks to less than one week and leading to a greater aerobic heterotrophic population over the incubation interval. The addition of phosphate also led to a aerobic heterotrophic bacterial community composed entirely of Micrococcus species.

Rogers, J.E.; McNair, V.M.; Li, S.W.; Garland, T.R.; Wildung, R.E.

1982-08-01

252

Laboratory Studies of the Formation of Carbon Aerosols on Titan  

NASA Astrophysics Data System (ADS)

The atmosphere of Titan is composed primarily of nitrogen and methane. Active organic chemistry occurs in the atmosphere producing an organic haze. During the Cassini/Huygens flyby mission, aromatic compounds (e.g., benzene, C6H6) were detected in the ionosphere at concentrations higher than expected. Benzene is a required precursor for larger aromatic species (e.g., Polycyclic Aromatic Hydrocarbons, PAHs) that may be part of aerosol particles. There is still debate about the interpretation of the results, and the implications for the characterization of the chemical haze, making it more urgent than ever to understand the formation and destruction processes of large carbon molecules in Titan's atmosphere. Photochemical modeling of the production of complex organic compounds in Titan's atmosphere is not fully understood. The modeled chemical pathway strongly enhances the PAH pathway to form, as do laboratory experiments on forming tholins (popular analogs to Titan's haze particles). The recent Cassini/Huygens results indicate that given the observed level of benzene in Titan's atmosphere, PAHs may be a major pathway for aerosol production. This motivated our project to investigate the role of PAHs, and nitrogen-containing PAHs (NPAHs), in the pathways from gas phase molecules to organic aerosols, in the laboratory. Combined cavity ring down spectroscopy and time-of-flight mass spectrometry studies of the products formed in discharge experiments, that allow in situ investigations of the formation of large molecular species and their conversion process into aerosols, are performed in order to understand and quantify the formation and destruction processes in Titan's atmosphere. The data will be used to constrain photochemical models of organic synthesis on Titan. We will describe the preliminary results from these experiments to address the issues in the characterization of Titan's haze. Acknowledgements: This research is supported by NASA SMD (Planetary Atmospheres Program). C. R. acknowledges the support of the NASA Postdoctoral Program (NPP).

Ricketts, Claire L.; Salama, F.

2008-09-01

253

A combined field and laboratory study of ploughing  

NASA Astrophysics Data System (ADS)

Many glaciers and ice sheets overlie soft sediment rather than hard bedrock. Basal motion of an ice mass over such a sedimentary bed can arise from sliding between ice and bed or pervasive deformation of the bed depending on the degree of coupling at the ice--bed interface. A transitional state between sliding and bed deformation entitled `ploughing' can occur when clasts that protrude into the glacier sole are dragged through the upper layer of the sediment. For rapidly sliding glaciers, excess pore-water pressures may develop downglacier from ploughing clasts such that sediment there weakens and provides little resistance to glacier motion. Thus, instead of these clasts leading to a strong coupling at the ice--bed interface, the ploughing process may help decouple the ice from the bed. A combined field and laboratory study is aimed at testing this hypothesis. In July 2002, newly designed ploughmeters, capable of simultaneoulsy measuring sediment strength and pore-water pressure, were installed beneath Unteraargletscher, Switzerland. These measurements are linked to records of subglacial water pressure and glacier surface velocity to estimate excess pore-water pressures and assess the degree of sediment weakening as a function of glacier speed. In addition, a laboratory apparatus (rotary-ploughing device) is currently being designed and constructed which will offer the possibility to conduct ploughing experiments by dragging instrumented objects through sediment under realistic subglacial conditions. Simultaneous measurements of the drag on these objects and the pore-water pressure in the sediment can then be used to investigate systematically the influence of sliding velocity and sediment properties on ice--bed coupling.

Rousselot, M.; Fischer, U. H.

2003-04-01

254

ELF electric and magnetic fields: Pacific Northwest Laboratory studies  

NASA Astrophysics Data System (ADS)

Studies were conducted at Battelle, Pacific Northwest Laboratory, to examine extremely-low-frequency (ELF) electromagnetic fields for possible biological effects in animals. Three areas of investigation are reported here: (1) studies on the nervous system, including behavior and neuroendocrine function; (2) experiments on cancer development in animals; and (3) measurements of currents and electric fields induced in animal models by exposure to external magnetic fields. In behavioral experiments, rats were shown to be responsive to ELF electric field exposure. Furthermore, experimental data indicate that short-term memory may be affected in albino rats exposed to combined ELF and static magnetic fields. Neuroendocrine studies were conducted to demonstrate an apparent stress-related response in rats exposed to 60-Hz electric fields. Nighttime pineal melatonin levels were shown to be significantly depressed in animals exposed to either electric or magnetic fields. A number of animal tumor models are currently under investigation to examine possible relationships between ELF exposure and carcinogenesis. Finally, theoretical and experimental measurements were performed which form the basis for animals and human exposure comparisons.

Anderson, L. E.

1992-06-01

255

ELF electric and magnetic fields: Pacific Northwest Laboratory studies  

SciTech Connect

Studies have been conducted at Battelle, Pacific Northwest Laboratory, to examine extremely-low-frequency (ELF) electromagnetic fields for possible biological effects in animals. Three areas of investigation are reported here: (1) studies on the nervous system, including behavior and neuroendocrine function, (2) experiments on cancer development in animals, and (3) measurements of currents and electric fields induced in animal models by exposure to external magnetic fields. In behavioral experiments, rats have been shown to be responsive to ELF electric field exposure. Furthermore, experimental data indicate that short-term memory may be affected in albino rats exposed to combined ELF and static magnetic fields. Neuroendocrine studies have been conducted to demonstrate an apparent stress-related response in rats exposed to 60-Hz electric fields. Nighttime pineal melatonin levels have been shown to be significantly depressed in animals exposed to either electric or magnetic fields. A number of animal tumor models are currently under investigation to examine possible relationships between ELF exposure and carcinogenesis. Finally, theoretical and experimental measurements have been performed which form the basis for animals and human exposure comparisons.

Anderson, L.E.

1992-06-01

256

A qualitative case study of instructional support for web-based simulated laboratory exercises in online college chemistry laboratory courses  

NASA Astrophysics Data System (ADS)

This study fills a gap in the research literature regarding the types of instructional support provided by instructors in online introductory chemistry laboratory courses that employ chemistry simulations as laboratory exercises. It also provides information regarding students' perceptions of the effectiveness of that instructional support. A multiple case study methodology was used to carry out the research. Two online introductory chemistry courses were studied at two community colleges. Data for this study was collected using phone interviews with faculty and student participants, surveys completed by students, and direct observation of the instructional designs of instructional support in the online Blackboard web sites and the chemistry simulations used by the participating institutions. The results indicated that the instructors provided multiple types of instructional support that correlated with forms of effective instructional support identified in the research literature, such as timely detailed feedback, detailed instructions for the laboratory experiments, and consistency in the instructional design of lecture and laboratory course materials, including the chemistry lab simulation environment. The students in one of these courses identified the following as the most effective types of instructional support provided: the instructor's feedback, opportunities to apply chemistry knowledge in the chemistry lab exercises, detailed procedures for the simulated laboratory exercises, the organization of the course Blackboard sites and the chemistry lab simulation web sites, and the textbook homework web sites. Students also identified components of instructional support they felt were missing. These included a desire for more interaction with the instructor, more support for the simulated laboratory exercises from the instructor and the developer of the chemistry simulations, and faster help with questions about the laboratory exercises or experimental calculations. Students believed that having this additional instructional support would lead to increased understanding of the laboratory exercises, allowing them to complete them with less difficulty, and giving them increased access to the instructor. Recommendations for the instructors of these two courses include: increased participation in the online course environment, increased emphasis on laboratory safety, and increased emphasis on the differences between simulated and real life chemistry laboratory experiments.

Schulman, Kathleen M.

257

Embargoed African Rodents and Monkeypox Virus  

MedlinePLUS

... 639-3311 Monkeypox Home > FACT SHEET Embargoed African Rodents and Monkeypox Virus On June 11, 2003, the ... joint order prohibiting the importation of all African rodents into the United States. The joint order also ...

258

A human laboratory pilot study with baclofen in alcoholic individuals.  

PubMed

Preclinical and clinical studies show that the GABA(B) receptor agonist baclofen may represent a pharmacotherapy for alcohol dependence (AD). However, the mechanisms by which baclofen affects drinking are not well characterized; thus this pilot study investigated possible baclofen's biobehavioral mechanisms. The design was a double-blind controlled randomized human laboratory pilot study. Fourteen non-treatment seeking alcohol-dependent heavy drinking subjects received either baclofen 10mg t.i.d. or an active placebo (cyproheptadine 2mg t.i.d., to control for sedation) for a 7-day period. At day 8, participants performed an alcohol cue-reactivity (CR) followed by an alcohol self-administration (ASA). Additionally, we explored possible moderators that might guide future larger studies, i.e. anxiety, family history and onset of alcoholism, and D4 dopamine receptor (DRD4) and 5-HTTLPR polymorphisms. The main results were a significant effect of baclofen for increasing stimulation (p=.001) and sedation (p<.01). Furthermore, when drinking during the ASA and the 2 days before was analyzed as a composite variable, there was a significant effect of baclofen to reduce alcohol consumption (p<.01). As for the exploratory analyses, baclofen's effects to increase alcohol sedation and to reduce alcohol consumption were limited to those individuals with DRD4 ?7 repeats (DRD4L). Yet, baclofen's effects on alcohol consumption were also moderated by 5-HTTLPR LL genotype. In conclusion, baclofen's ability to reduce alcohol drinking may be related to its effects on the biphasic effects of alcohol, but larger studies are needed to confirm these preliminary findings. PMID:23262301

Leggio, Lorenzo; Zywiak, William H; McGeary, John E; Edwards, Steven; Fricchione, Samuel R; Shoaff, Jessica R; Addolorato, Giovanni; Swift, Robert M; Kenna, George A

2012-12-19

259

Chemical reaction and dust formation studies in laboratory hydrocarbon plasmas.  

NASA Astrophysics Data System (ADS)

Plasma chemical reaction studies with relevance to, e.g., Titan's atmosphere have been per-formed in various laboratory plasmas [1,2]. Chemical reactions in a dielectric barrier discharge at medium pressure of 250-300 mbar have been studied in CH4 /N2 and CH4 /Ar gas mixtures by means of mass spectrometry. The main reaction scheme is production of H2 by fragmenta-tion of CH4 , but also production of larger hydrocarbons like Cn Hm with n up to 10 including formation of different functional CN groups is observed. [1] A. Majumdar and R. Hippler, Development of dielectric barrier discharge plasma processing apparatus for mass spectrometry and thin film deposition, Rev. Sci. Instrum. 78, 075103 (2007) [2] H.T. Do, G. Thieme, M. Frühlich, H. Kersten, and R. Hippler, Ion Molecule and Dust Particle Formation in Ar/CH4 , Ar/C2 H2 and Ar/C3 H6 Radio-frequency Plasmas, Contrib. Plasma Phys. 45, No. 5-6, 378-384 (2005)

Hippler, Rainer; Majumdar, Abhijit; Thejaswini, H. C.

260

Laboratory study of selected personal inhalable aerosol samplers.  

PubMed

Assessment of inhalable dust exposure requires reliable sampling methods in order to measure airborne inhalable particles' concentrations. Many inhalable aerosol samplers can be used but their performances widely vary and remain unknown in some cases. The sampling performance of inhalable samplers is strongly dependent on particle size and ambient air velocity. Five inhalable aerosol samplers have been studied in two laboratory wind tunnels using polydisperse glass-beads' test aerosol. Samplers tested were IOM sampler (UK), two versions of CIP 10-I sampler, v1 and v2 (F), 37-mm closed face cassette sampler (USA), 37-mm cassette fitted up with an ACCU-CAP insert (USA), and Button sampler (USA). Particle size-dependent sampling efficiencies were measured in a horizontal wind tunnel under a 1 m s(-1) wind velocity and in a vertical tunnel under calm air, using a specific method with Coulter(R) counter particle size number distribution determinations. Compared with CEN-ISO-ACGIH sampling criteria for inhalable dust, the experimental results show fairly high sampling efficiency for the IOM and CIP 10-I v2 samplers and slightly lower efficiencies for the Button and CIP 10-I v1 samplers. The closed face cassette (4-mm orifice) produced the poorest performances of all the tested samplers. This can be improved by using the ACCU-CAP internal capsule, which prevents inner wall losses inside the cassette. Significant differences between moving air and calm air sampling efficiency were observed for all the studied samplers. PMID:20147627

Görner, Peter; Simon, Xavier; Wrobel, Richard; Kauffer, Edmond; Witschger, Olivier

2010-02-10

261

Laboratory Study of Solar Flare Dynamics in MRX  

NASA Astrophysics Data System (ADS)

We will present an experimental study of the dynamics of half-toroidal plasma arcs relevant to solar coronal activities utilizing the existing MRX facility [1,2]. A set of electrodes are inserted in MRX to generate a variety of plasma flux loops which contain variable toroidal guide field. Three dimensional evolution of the simulated flares is monitored by an ultra fast framing camera. The time evolution of discharges with Argon, Helium and Hydrogen with currents of 5-15 kA show the stability condition for a line-tied plasma flux loop similar to those on the solar surface. With the initial data it is shown that the q value, which describes the rotational transform of field lines, is the key for characterizing the global stability. Our experimental results will contribute to the understanding of evolution of magnetic topology of the solar flare including concepts such as current sheets, stability of current carrying flares, and line-tying, which are vitally important for understanding the Solar/Heliospheric and Interplanetary Environment. [1] M. Yamada, H. Ji, S. Hsu, T. Carter, R. Kulsrud, N. Bretz, F. Jobes, Y. Ono, and F. Perkins. Study of driven magnetic reconnection in a laboratory plasma. Phys. Plasmas, 4:1936, 1997. [2] V.S. Titov and P. D'emoulin. Basic topology of twisted magnetic configurations in solar flares. Astron.and Astrophys., 351:707, 1999.

Oz, E.; Yamada, M.; McGeehan, B.; Dorfman, S.; Ji, H.

2008-12-01

262

Francisella tularensis in Rodents, China  

Microsoft Academic Search

A total of 420 rodents in China were examined for Francisella tularensis by polymerase chain reaction. The infection rates were 4.76% in total, and 11.65%, 10.00%, 6.56%, 1.77%, and 0% in Jilin, Xinjiang, Heilongjiang, Inner Mongolia, and Zhejiang, respectively. Sequence analysis showed that all the detected agents belonged to F. tularen- sis subsp. holarctica.

Fang Zhang; Wei Liu; May C. Chu; Jun He; Qing Duan; Xiao-Ming Wu; Pan-He Zhang; Qiu-Min Zhao; Hong Yang; Zhong-Tao Xin; Wu-Chun Cao

2006-01-01

263

21 CFR 1250.96 - Rodent control.  

Code of Federal Regulations, 2010 CFR

...2010-04-01 2010-04-01 false Rodent control. 1250.96 Section 1250.96...and Conditions on Vessels § 1250.96 Rodent control. Vessels shall be maintained free of rodent infestation through the use of traps,...

2010-04-01

264

21 CFR 1250.96 - Rodent control.  

Code of Federal Regulations, 2010 CFR

...2009-04-01 2009-04-01 false Rodent control. 1250.96 Section 1250.96...and Conditions on Vessels § 1250.96 Rodent control. Vessels shall be maintained free of rodent infestation through the use of traps,...

2009-04-01

265

The Study of a Cobalt Complex--A Laboratory Project.  

ERIC Educational Resources Information Center

|Describes an 8-week project involving the synthesis of cobalt compounds. Once synthesized, compounds are qualitatively and quantitatively analyzed. Background information, laboratory procedures, and results/discussion are provided for three project experiments. (Author/JN)|

Loehlin, James H.; And Others

1982-01-01

266

Laboratory Simulation of Rainfall Erosivity for Gully Formation Study.  

National Technical Information Service (NTIS)

The objective was to develop a rainfall simulator, which imparts to the laboratory rainfall the more important characteristics of natural rainfall such as intensity, drop spectrum, kinetic energy, and momentum at impact, for using in soil erosion research...

T. Y. Kao

1974-01-01

267

Laboratory Studies of Gravity Wave, Mean Flow Interactions.  

National Technical Information Service (NTIS)

Laboratory observations of gravity wave, critical layer experiments are presented. In the experiments, a stratified shear flow is generated, and internal gravity waves are allowed to propagate into the flow. The waves propagate up to, but no farther than,...

D. P. Delisi

1995-01-01

268

Laboratory Studies of Gravity Wave/Mean Flow Interactions.  

National Technical Information Service (NTIS)

Progress is reported on laboratory measurements of gravity wave/critical layer interactions. Previous results have been reported for the interactions of single monochromatic waves propagating in a stratified fluid with a vertical velocity shear. The new r...

D. P. Delisi

1993-01-01

269

RAINFALL SIMULATOR FOR LABORATORY USE IN ACIDIC PRECIPITATION STUDIES  

EPA Science Inventory

A rainfall simulator, developed on the principle of droplet formation from needle tips, is described. The simulator is designed for laboratory experimentation to examine the effects of acidic precipitation on terrestrial plants. The system offers sufficient flexibility to simulat...

270

Thermal Infrared Investigation on Cassini: A Challenge for Laboratory Studies.  

National Technical Information Service (NTIS)

Slides about the Composite Infrared Spectrometer (CIRS) examine Cassini remote sensing spectral coverage; instrument description; thermal-vacuum testing; mechanical layout; laboratory spectroscopy and Voyager IRIS; composite brightness temperature of Tita...

D. Jennings

2010-01-01

271

The Study of a Cobalt Complex--A Laboratory Project.  

ERIC Educational Resources Information Center

Describes an 8-week project involving the synthesis of cobalt compounds. Once synthesized, compounds are qualitatively and quantitatively analyzed. Background information, laboratory procedures, and results/discussion are provided for three project experiments. (Author/JN)

Loehlin, James H.; And Others

1982-01-01

272

Laboratory Study of Heavy Oil Recovery Using Polymer and Solvent.  

National Technical Information Service (NTIS)

An enhanced heavy oil recovery process using polymer and solvent was laboratory tested. The objectives were to increase oil recovery by (1) controlling bypassing of injected fluids through high permeability sands by the use of polymer and multivalent ion ...

G. D. Peterson H. J. Lechtenberg W. H. Caraway G. L. Gates

1976-01-01

273

Environmental Management Plan Study and Report: MDOT - Materials Laboratories.  

National Technical Information Service (NTIS)

The goal of this EMP was to develop and implement a comprehensive Environmental Management Plan for MDOT Materials Laboratories. This goal was achieved through performance of environmental audits to identify potential environmental impacts, and by identif...

2012-01-01

274

Study of the Effectiveness of the Instructional Systems Laboratory.  

National Technical Information Service (NTIS)

A survey examined perception and use of the services of the Instructional Systems Laboratory (ISL) by the faculty of the University of Minnesota's College of Education. The questionnaire, mailed to all College of Education faculty members, emphasized facu...

W. D. Philipson P. W. Chan-Tam

1983-01-01

275

Feasibility study of medical isotope production at Sandia National Laboratories.  

National Technical Information Service (NTIS)

In late 1994, Sandia National Laboratories in Albuquerque, New Mexico, (SNL/NM), was instructed by the Department of Energy (DOE) Isotope Production and Distribution Program (IPDP) to examine the feasibility of producing medically useful radioisotopes usi...

C. D. Massey D. L. Miller S. D. Carson

1995-01-01

276

Study of driven magnetic reconnection in a laboratory plasma  

SciTech Connect

The Magnetic Reconnection Experiment (MRX) has been constructed to investigate the fundamental physics of magnetic reconnection in a well controlled laboratory setting. This device creates an environment satisfying the criteria for a magnetohydrodynamic (MHD) plasma (S {much_gt} 1, {rho}{sub i} {much_lt} L). The boundary conditions can be controlled externally, and experiments with fully three-dimensional reconnection are now possible. In the initial experiments, the effects of the third vector component of reconnecting fields have been studied. Two distinctively different shapes of neutral sheet current layers, depending on the third component, are identified during driven magnetic reconnection. Without the third component (anti-parallel or null-helicity reconnection), a thin double-Y shaped diffusion region is identified. A neutral sheet current profile is measured accurately to be as narrow as order ion gyro-radius. In the presence of an appreciable third component (co-helicity reconnection), an O-shaped diffusion region appears and grows into a spheromak configuration.

Yamada, Masaaki; Ji, H.; Hsu, S.; Carter, T.; Kulsrud, R.; Bretz, N.; Jobes, F.; Ono, Yasushi; Perkins, F.

1998-12-31

277

A Review of the Current Status of MRI Laboratory Studies  

NASA Astrophysics Data System (ADS)

The Magnetorotational instability (MRI) is sufficiently generic that it should be producible in laboratory experiments. This talk will discuss the latest results from three liquid-metal studies of the MRI, and how those results may apply to astrophysical settings. The results of the first group to claim observation of the MRI, using the Maryland spherical Couette experiment, will be described. The reported observations were in the presence of a turbulent background state, and were non-axisymmetric, in contrast to the expected behavior. The PROMISE experiment group has reported the observation of the Helical MRI in their Taylor-Couette experiment, in which a combined axial-azimuthal magnetic field is applied to the flow. The important role of boundary conditions will be discussed in the context of this experiment. Finally, the latest results from the Princeton MRI experiment will be presented. This experiment is capable of generating high-Reynolds-number laminar flows, allowing, in principle, the observation of the MRI to the exclusion of other instabilities.

Spence, Erik J.

2010-05-01

278

Impacts of Stratospheric Particles Injection on Stratospheric Ozone: Laboratory Studies  

NASA Astrophysics Data System (ADS)

The stratospheric injection of aerosols is a geoengineering scheme designed to reduce the impacts of climate change. The injected particles scatter solar radiation back to space and hence reduce the radiative forcing of the Earth. The scattering ability of a particle depends on both its size and composition. Particles composed of titania (TiO2) have recently been highlighted as a possible candidate aerosol because of their impressive light scattering ability by virtue of a high refractive index (Pope et al. 2012). The impact of particles injection on stratospheric ozone needs to be systematically assessed via laboratory and modelling studies. In this work, the heterogeneous reactions of airborne TiO2 particles with N2O5 and HCl are investigated by using an atmospheric pressure aerosol flow tube. A Chemical Ionization Mass Spectrometer is used to detect trace gases, and a Scanning Mobility Particle Sizer is used to measure aerosol number concentration and size distribution. The kinetics of the uptake of N2O5 onto TiO2 particles and the influence of HCl will be presented, and the result will be compared to the uptake onto natural sulphate stratospheric particles.

Tang, Mingjin; Rkiouak, Laylla; Fuller, Steve; Pope, Francis; Cox, Tony; Watson, Matt; Kalberer, Markus

2013-04-01

279

Meteoric water - basalt interactions: a field and laboratory study  

SciTech Connect

The goal of this study is to define and interpret the composition of the meteoric waters in N.E. Iceland in their cycle through the hydrosphere and the upper part of the crust, and to calibrate the natural process by dissolution experiments done in the laboratory. The composition of rain, snow, spring and geothermal waters from the rift zone of N.E. Iceland can be explained by sea-spray addition (1/10000), dissolution of basalts and buffering by alteration minerals. Rates, stoichiometry and activation energy of dissolution, pH vs. time and activity-activity paths were determined by dissolving basaltic rocks under simulated natural conditions at 25 to 60/sup 0/C. Dissolution follows a linear rate law, with basaltic glass dissolving 10 times faster than the crystalline basalt. Rates are independent of pH from 7 to 10. The average activation energy for dissolution of basaltic glass is 31.8 kJ/mol (+/-3). For individual elements leached from crystalline basalt it ranges from 35 to 15 kJ/mol. This indicates that under the experimental conditions reactions on the surfaces of the solids are the rate determining step in the dissolution mechanism. Considerable differences (2 to 4 log units) exist in the calculated oxygen fugacities obtained from different redox species in the geothermal fluids. This is primarily caused by the nonequilibrium state of the sulfur redox pair.

Gislason, S.R.

1985-01-01

280

Pathology of rodent models of intestinal cancer: progress report and recommendations.  

PubMed

In October 2010, a pathology review of rodent models of intestinal neoplasia was held at The Jackson Laboratory. This review complemented 2 other concurrent events: a workshop on methods of modeling colon cancer in rodents and a conference on current issues in murine and human colon cancer. We summarize the results of the pathology review and the committee's recommendations for tumor nomenclature. A virtual high-resolution image slide box of these models has been developed. This report discusses significant recent developments in rodent modeling of intestinal neoplasia, including the role of stem cells in cancer and the creation of models of metastatic intestinal cancer. PMID:23415801

Washington, Mary Kay; Powell, Anne E; Sullivan, Ruth; Sundberg, John P; Wright, Nicholas; Coffey, Robert J; Dove, William F

2013-02-12

281

A case study of virtual circuit laboratory for undergraduate student courses  

Microsoft Academic Search

The purpose of this study is to design and develop a Web based circuit virtual laboratory for undergraduate student courses, which can be treated as an accessorial tool for enhancing instruction. The study firstly reviews the general concept of virtual laboratory and some related works. Secondly, the design and development of the system framework of this circuit virtual laboratory is

Gu Rong; Zhu Miaoliang; Dong Yabo; Shi Dandan; Wang Yonggu

2005-01-01

282

Tethered Gravity Laboratories Study (Quarterly Progress Report Number 7, August 25-November 24, 1989).  

National Technical Information Service (NTIS)

Tethered gravity laboratories study is presented. The following subject areas are covered: variable gravity laboratory; attitude tether stabilizer; configuration analysis (AIT); dynamic analysis (SAO); and work planned for the next reporting period.

F. Lucchetti

1989-01-01

283

Laboratory and modelling studies on the atmospheric stability of levoglucosan  

NASA Astrophysics Data System (ADS)

Aerosol particles are known to influence important atmospheric processes such as cloud formation and the solar radiation budget. Therefore, much effort is spend to characterise and locate the sources of atmospheric particles. Source apportionment studies using molecular tracer compounds are a common approach to distinguish between different sources. The anhydromonosaccharide levoglucosan (1,6-anhydro-?-D-glucopyranose) is an widely used and very specific tracer compound for particle emissions from natural and anthropogenic biomass combustion processes. Levoglucosan is formed in large quantities during the pyrolysis of cellulose at temperatures above 300° C. Even if levoglucosan is widely used in source apportionment studies only few studies investigated the atmospheric stability of this tracer compound so far. Furthermore, oxidation processes by free radicals in aqueous particles are not yet considered as a potential sink reaction for this highly water soluble compound. Therefore, detailed kinetic studies on the reactivity of levoglucosan towards three important atmospheric free radicals (OH, NO3 and SO4-) in aqueous solutions were performed for the first time using the laser flash photolysis technique. Laboratory studies on the stability of levoglucosan were done both in the presence and absence of other water soluble reaction partners. The results obtained in the different experiments will be presented, compared and discussed. Furthermore, the experimental data were implemented into the parcel model SPACCIM (Spectral Aerosol Cloud Chemistry Interaction Model; Wolke et al., 2005) in order to study the degradation fluxes of levoglucosan in cloud droplets and aqueous particles considering a detailed microphysics and multiphase chemistry. The model calculations, performed under different conditions (summer, winter, with cloud passages, without cloud passages, different relative humidity and iron contents), show that levoglucosan can be oxidised readily by OH radicals in the tropospheric aqueous phase. Mean degradation fluxes of about 7.2 ng m-3 h-1 in summer and 4.7 ng m-3 h-1 in winter were calculated. The detailed results of the model calculations will be presented and the influence of the different model scenarios on the calculated degradation fluxes discussed. Model calculations demonstrate that under certain atmospheric conditions the oxidation of levoglucosan can be as fast as that of other atmospherically relevant organic compounds and it may not be as stable as previously thought in the atmosphere particularly under high relative humidity conditions. References: Wolke, R.; Sehili, A. M.; Simmel, M.; Knoth, O.; Tilgner, A.; Herrmann, H. SPACCIM: A parcel model with detailed microphysics and complex multiphase chemistry. Atmos. Environ. 2005, 39, 4375-4388.

Tilgner, Andreas; Hoffmann, Dirk; Iinuma, Yoshiteru; Herrmann, Hartmut

2010-05-01

284

The laboratory animal boards study group: A multifaceted tool for preparation for the American College for Laboratory Medicine board examination.  

PubMed

Preparation for the specialty board examination for the American College of Laboratory Animal Medicine (ACLAM) is an intensive process that is facilitated by geographic regions where many people studying for the exam are located in close proximity. However, many people work at institutions that are distant from these 'study centers'. Approximately 10 y ago, the Laboratory Animal Boards Study Group (LABSG) online journal club was established to provide a forum for journal review for examination preparation. Over the years, the mission of this group has expanded to include practice examinations and practicals, questions from common resources, and summaries and questions from common laboratory animal science journals. These study aids are beneficial for those preparing for the ACLAM certification examination. They are also beneficial for those preparing for the technician and manager certification examinations offered by the American Association for Laboratory Animal Science (AALAS). This article is intended to be an introduction to the variety of study aids available through the LABSG online journal review club and the LABSG web page (www.labsg.org). It also provides details on the demographics of participants and an exploration of how this resource enhances examination preparation. PMID:16884177

Hickman, Debra; King-Herbert, Angela; Murphy, Stephanie J

2006-07-01

285

Performance of dust allergen carpet samplers in controlled laboratory studies.  

PubMed

Allergens and other pollutants in house dust are collected using a variety of dust samplers that are assumed to operate similarly. This factorial design study compared sampler performance under controlled environmental conditions. House dust with known particle sizes (212-90, 90-45, and <45??m) and allergen concentrations were sampled from new carpet squares with varying denier, pile height and pile densities. Dust mass and allergen recovery for total dust mites (Der p 1 and Der f 1), cat (Fel d 1) and cockroach allergen (Bla g 1) were assessed using the Eureka Mighty Mite (EURK), the High Volume Small Surface Sampler (HVS), or the American Industrial Hygiene Association (AIHA) method. Allergen concentrations were quantified using enzyme-linked immunosorbent assays, and dust mass results were corrected for carpet fiber shedding. Samplers were compared by exploring mass collection efficiency (CE=fiber corrected dust mass/applied dust mass) and concentration ratio (CR=allergen concentration in collected sample/allergen concentration in test dust). Test dust allergen concentrations varied by particle size fraction due to varying laboratory performance over time. The EURK and HVS samplers had CEs of 41-63% in the small and medium particle size fractions, and collected less than 20% of the available dust from the large size fraction. The AIHA CE ranged from 10% to 17% in the medium and small particle size fractions, but collected little dust in the largest particle size fraction. The AIHA and HVS samplers were more likely to acquire more representative and less variable allergen CRs compared with the EURK method. Health studies that use allergen concentration as an exposure metric need to consider the implications of sampler performance when interpreting links to health outcomes and development of health-based standards for allergens in house dust. PMID:23281430

Adgate, John L; Banerjee, Sudipto; Wang, Mei; McKenzie, Lisa M; Hwang, Jooyeon; Ja Cho, Sook; Ramachandran, Gurumurthy

2013-01-02

286

Critical review and evaluation of the uterotrophic bioassay for the identification of possible estrogen agonists and antagonists: in support of the validation of the OECD uterotrophic protocols for the laboratory rodent. Organisation for Economic Co-operation and Development.  

PubMed

A current issue for regulatory agencies is endocrine-related modes of action such as those mediated by the estrogen, androgen, and thyroid nuclear receptors. At the national and international levels, the consensus recommendation for the assessment of such modes of action is a tiered series of in vitro and in vivo protocols. The tiered framework begins with screens for structural alerts and then moves to rapid, mechanistic in vitro screening assays, and then to in vivo screening bioassays. The objective of these screens is to identify substances that may warrant testing for endocrine-mediated adverse effects. The final framework tier as needed is to test these substances in long-term bioassays for adverse endocrine-mediated reproductive and/or developmental effects. The subject of this review, the rodent uterotrophic bioassay, is intended to be a rapid in vivo screening bioassay for possible estrogen agonists and based on the response of the estrogen-sensitive uterus. The central metric of bioassay is a statistically significant increase in the weight of the uterus after 3 consecutive days of test substance administration. The extensive background literature is summarized in this review on the mode of action underlying the bioassay and the uterine response to estrogens. The review includes the bioassay's history of development and how its employment has changed and evolved over time. The review describes two major uterotrophic bioassay versions, the intact, immature female and the mature, ovariectomized female, and the protocol factors likely to influence relevance, reproducibility, and reliability of bioassay. The emphasis of the review is the ability of the uterotrophic bioassay to identify the substances of current interest: weak estrogen agonists with binding affinities relative to the natural 17beta-estradiol in the log 0 to log -3 range. Using selected model substances having RBAs in this target range, the bioassay's performance in a hierarchical, tiered approach is evaluated, including the predictive capability of the uterotrophic bioassay based on available reproductive and developmental testing data. The review concludes that the uterotrophic bioassay is reliable and can identify substances that may act via an estrogen-mode of action, supporting the validity of the uterotrophic bioassay and its regulatory use as an in vivo mechanistic screening bioassay for estrogen agonists and antagonists. PMID:12487363

Owens, J William; Ashby, John

2002-01-01

287

Assays of homeopathic remedies in rodent behavioural and psychopathological models.  

PubMed

The first part of this paper reviews the effects of homeopathic remedies on several models of anxiety-like behaviours developed and described in rodents. The existing literature in this field comprises some fifteen exploratory studies, often published in non-indexed and non-peer-reviewed journals. Only a few results have been confirmed by multiple laboratories, and concern Ignatia, Gelsemium, Chamomilla (in homeopathic dilutions/potencies). Nevertheless, there are some interesting results pointing to the possible efficacy of other remedies, and confirming a statistically significant effect of high dilutions of neurotrophic molecules and antibodies. In the second part of this paper we report some recent results obtained in our laboratory, testing Aconitum, Nux vomica, Belladonna, Argentum nitricum, Tabacum (all 5CH potency) and Gelsemium (5, 7, 9 and 30CH potencies) on mice using ethological models of behaviour. The test was performed using coded drugs and controls in double blind (operations and calculations). After an initial screening that showed all the tested remedies (except for Belladonna) to have some effects on the behavioural parameters (light-dark test and open-field test), but with high experimental variability, we focused our study on Gelsemium, and carried out two complete series of experiments. The results showed that Gelsemium had several effects on the exploratory behaviour of mice, which in some models were highly statistically significant (p < 0.001), in all the dilutions/dynamizations used, but with complex differences according to the experimental conditions and test performed. Finally, some methodological issues of animal research in this field of homeopathy are discussed. The "Gelsemium model" - encompassing experimental studies in vitro and in vivo from different laboratories and with different methods, including significant effects of its major active principle gelsemine - may play a pivotal rule for investigations on other homeopathic remedies. PMID:19945676

Bellavite, Paolo; Magnani, Paolo; Marzotto, Marta; Conforti, Anita

2009-10-01

288

Laboratory studies of free radical reactions in cloudwater  

SciTech Connect

Reactions in cloudwater can be important pathways for chemical transformation of atmospheric trace gases because of high solubility of reagent gases, rapid aqueous-phase kinetics, and large thermodynamic driving force. A key cloudwater reaction is oxidized of dissolved SO{sub 2} and H{sub 2}O{sub 2}. It is thus important to understand processes controlling H{sub 2}O{sub 2} formation in the atmosphere by gas- and aqueous-phase reactions of HO{sub 2} free radicals. A concern with models of free radical chemistry in cloudwater is that of the applicability of present chemical kinetic schemes to such complex milieus. This concern arises because, at the low free-radical concentrations expected for cloudwater, reactions of radicals with trace impurities are favored over radical-radical reactions, which dominate at high radical concentrations commonly employed in laboratory investigations. We report initial results of a study in which the rate of change in H{sub 2}O{sub 2} concentration is monitored in synthetic and authentic cloudwater in which HO{sub 2} radicals are produced by {sup 60}Co{gamma} radiolysis at rates comparable to those expected upon transfer of HO{sub 2} from interstitial cloud air to cloudwater. These results indicate that micromolar concentrations of Fe(III) decrease H{sub 2}O{sub 2} yields and can even lead to H{sub 2}O{sub 2} loss rather than formation. Implications on cloud chemistry will be discussed. 14 refs., 2 figs.

Schwartz, S. E.; Weinstein-Lloyd, J.

1989-11-01

289

Dissociative Electron Attachment to Hydrocarbons. A Laboratory Study  

NASA Astrophysics Data System (ADS)

Laboratory studies of PAHs continue to be essential if we are to interpret the wealth and variety of processes contributing to star formation. In the realm of gas-phase kinetics reactions involving negative ions are being studied to help modellers understand the role of these species in interstellar chemistry. Observations have shown that PAHs molecules are abundant and ubiquitous in the interstellar medium of galaxies, play an important role in its physical and chemical characteristics and form a key link between small hydrocarbon species and large carbonaceous grains. There is therefore considerable interest in the mechanisms by which these molecules and their anions may form. One method is electron induced chemistry within the icy mantles on the surface of dust grains. In particular it has been recently shown that functional group dependence exists in electron attachment processes giving rise to site selective fragmentation of molecules at the C-H, O-H and N-H bonds at energies well beyond the threshold for the breaking of any of these bonds allowing novel forms of chemistry that have little or no activation barriers, such as are necessary in the ISM. In this poster we present the results of recent studies on dissociative electron attachment (DEA) to PAHs using an improved version of a Velocity Map Imaging (VMI) spectrometer comprised of a magnetically collimated and low energy pulsed electron gun, a Faraday cup, an effusive molecular beam, a pulsed field ion extraction, a time of flight analyzer and a two-dimensional position sensitive detector consisting of microchannel plate and a phosphor screen. The VMI spectrometer measures the kinetic energy and angular distribution of the fragment anions produced in the dissociative electron attachment process. Kinetic energy measurements provide information on the internal energies of the fragment anions and determine the dissociation limits of the parent negative ion resonant states responsible for the dissociative electron attachment process. Angular distribution measurements provide information about the symmetry of these negative ion resonant states. We shall present the details, results and conclusions of these measurements during the conference for some illustrative hydrocarbons.

Szymanska, E.; Mason, N. J.

2011-05-01

290

Development and implementation of multimedia content for an electronic learning course on rodent surgery.  

PubMed

The development of new rodent models of human disease and advances in surgical equipment and technologies have increased the demand for expertise in rodent surgery. Because of the limited availability of rodent surgical training courses, electronic (e-) learning is presented as an alternative to in-person education and as a means to hone the expertise of current surgeons in biomedical research, similar to e-learning applications for human surgery training. Translating this model to the biomedical research field provides participants with an opportunity to train themselves on rodent surgical techniques prior to operating on live models. An e-learning rodent surgery course was incorporated into a training class of undergraduate (n = 39) and graduate (n = 12) laboratory animal students, and a portion of the course was presented to laboratory animal professionals (n = 15). The effectiveness of the method was evaluated using written examination and postcourse surveys. The exam data demonstrated that the e-learning course transferred knowledge comparable to a lecture course on surgery that was presented in-person. Students responded favorably to videos, step-by-step photographs of surgical procedures, and the ready accessibility of the course. Critiques included the need to improve video resolution and quality of the voice-overs. These results support the continued development and implementation of electronic rodent surgical technique courses for use in laboratory animal and biomedical research communities. PMID:20587161

Baran, Szczepan W; Johnson, Elizabeth J; Kehler, James; Hankenson, F Claire

2010-05-01

291

Persistence of brodifacoum in cockroach and woodlice: Implications for secondary poisoning during rodent eradications.  

PubMed

When planning rodent eradications, that normally involve the use of the anticoagulant poison brodifacoum, it is imperative to minimise impacts on other "non-target" species that dwell alongside the targeted rodents and may indeed be the intended beneficiaries of the eradication. Such impacts can arise either from primary poisoning when the non-target species ingest bait pellets containing toxicant or by secondary poisoning when the non-target species eats prey that has itself eaten brodifacoum. Cockroaches and woodlice, likely to scavenge bait pellets, are widely distributed on tropical and sub-tropical islands where they are eaten by ground-dwelling birds. Combining work on Henderson Island, South Pacific, site of a recent rat eradication project, and UK laboratory experiments, our study first measured brodifacoum concentrations in cockroaches given temporary ad lib access to poison bait pellets, approximately mimicking the aftermath of bait distribution for a rodent eradication. In two separate experiments using different species/exposure times, the mean brodifacoum concentrations among cockroaches immediately after bait exposure was 262±s.e. 131 and 477±168µgkg(-1) wet weight. Values decreased quickly in the following 2 weeks, and then continued to decline at a slower rate over the following 4 weeks in the more prolonged laboratory experiment. A supplementary experiment with woodlice recorded a similar brodifacoum concentration in the animals at the end of the exposure period, 223±66µgkg(-1), and a similar time course for the post-exposure decline. In the context of rails (Rallidae), a group of birds known to be particularly susceptible to primary brodifacoum poisoning, these results suggested that, in terms of acute exposure, individual birds would need to eat a minimum of their own body weight (and more commonly 2-5 times that) of live cockroaches before facing a 50% risk of death. Therefore, we conclude that in eradication scenarios, acute secondary poisoning is of lower concern for these birds than primary poisoning. PMID:24008155

Brooke, M de L; Cuthbert, R J; Harrison, G; Gordon, C; Taggart, M A

2013-09-02

292

d-chiro-Inositol is absorbed but not synthesized in rodents  

PubMed Central

d-chiro-Inositol (DCI) and pinitol (1D-3-O-methyl-chiro-inositol) are distinctive inositols reported to possess insulin-mimetic properties. DCI-containing compounds were abundant in common laboratory animal feed. By GC-MS of 6 M-HCl hydrolysates, Purina Laboratory Rodent Diet 5001 (diet 5001) contained 0.23% total DCI by weight with most found in the Lucerne and soy meal components. In contrast, only traces of l-chiro-inositol were observed. The DCI moiety was present in a water-soluble non-ionic form of which most was shown to be pinitol. To measure the absorption of dietary inositols, rats were fed diet 5001 in a balance study or given purified pinitol or [2H6]DCI. More than 98% of the total DCI fed to rats as diet 5001, purified pinitol or [2H6]DCI was absorbed from the gastrointestinal tract. Rats chronically on diet 5001 consumed 921 ?mol total DCI/kg body weight pet d but excreted less than 5.3% in the stool and urine, suggesting that the bulk was metabolized. The levels of pinitol or DCI in plasma, stool, or urine remained relatively stable in mice fed Purina PicoLab® Rodent Diet 20 5053 over a 5-week period, whereas these values declined to very low levels in mice fed a pinitol/DCI-deficient chemically-defined diet. To test whether DCI was synthesized or converted from myo-inositol, mice were treated with heavy water or [2H6]myo-inositol. DCI was neither synthesized endogenously from 2H-labelled water nor converted from [2H6]myo-inositol. DCI and pinitol in rodents appear to be derived solely from the diet.

Lin, Xiaobo; Ma, Lina; Gopalan, Chaya; Ostlund, Richard E.

2013-01-01

293

Microbial Evolution at High Pressure: Deep Sea and Laboratory Studies  

NASA Astrophysics Data System (ADS)

Elevated hydrostatic pressures are present in deep-sea and deep-Earth environments where this physical parameter has influenced the evolution and characteristics of life. Piezophilic (high-pressure-adapted) microbes have been isolated from diverse deep-sea settings, and would appear likely to occur in deep-subsurface habitats as well. In order to discern the factors enabling life at high pressure my research group has explored these adaptations at various levels, most recently including molecular analyses of deep-sea trench communities, and through the selective evolution of the model microbe Escherichia coli in the laboratory to progressively higher pressures. Much of the field work has focused on the microbes present in the deeper portions of the Puerto Rico Trench (PRT)and in the Peru-Chile Trench (PCT), from 6-8.5 km below the sea surface (~60-85 megapascals pressure). Culture-independent phylogenetic data on the Bacteria and Archaea present on particles or free-living, along with data on the microeukarya present was complemented with genomic analyses and the isolation and characterization of microbes in culture. Metagenomic analyses of the PRT revealed increased genome sizes and an overrepresentation at depth of sulfatases for the breakdown of sulfated polysaccharides and specific categories of transporters, including those associated with the transport of diverse cations or carboxylate ions, or associated with heavy metal resistance. Single-cell genomic studies revealed several linneages which recruited to the PRT metagenome far better than existing marine microbial genome sequences. analyses. Novel high pressure culture approaches have yielded new piezophiles including species preferring very low nutrient levels, those living off of hydrocarbons, and those adapted to various electron donor/electron acceptor combinations. In order to more specifically focus on functions enabling life at increased pressure selective evolution experiments were performed with Escherichia coli during laboratory cultivation. More than 60 subcultures were obtained at progressively increasing hydrostatic pressures ranging from 28 - 62 megapascals. A strain isolated from the 63rd subculture displayed dramatically improved growth over the parental strain at 59 megapascals but reduced growth rate relative to the parental strain at atmospheric pressure. The mutant also produced far more unsaturated fatty acids than its parent and also acquired the ability to upregulate these fatty acids species at elevated pressure. Solexa sequencing revealed mutations within an operon (acpP operon) governing unsaturated fatty acid production, and these have been examined as a function of generation at high pressure. These and other results indicate that a large number and variety of microbes are adapted to life at high pressure, that the selective constraints of pressure increases up to ~60 megapascals are not so severe as to preclude the rapid evolution to a piezotolerant phenotype, and that the production of increased levels of unsaturated fatty acids correlates with adaptation to this stressor. This work was supported by grants from the National Science Foundation (EF-0801793 and EF-0827051) and the National Aeronautics and Space Administration (NASA SSC NNX10AR13G).

Bartlett, D. H.

2011-12-01

294

COMPARISON OF FIELD- AND LABORATORY-DEVELOPED ESTUARINE BENTHIC COMMUNITIES FOR TOXICANT-EXPOSURE STUDIES  

EPA Science Inventory

The structures of macrobenthic communities that colonized sand-filled boxes in laboratory and field were compared to learn if laboratory-developed assemblages of animals used in toxicity studies realistically simulate those in nature. Laboratory boxes were colonized for eight wee...

295

Laboratory study of water immobilization for improved oil recovery  

Microsoft Academic Search

In most oil reservoirs, injected water tends to follow the paths taken by previously injected water. If some of the paths that have been water-swept could be immobilized, continued waterflooding might sweep new paths and yield more oil than traditional waterflooding. Laboratory experiments were conducted in which vertical unconsolidated cores were waterflooded to breakthrough. Various fractions of the water-swept volume

D. N. Meehan; D. E. Menzie; H. Crichiow

1977-01-01

296

A laboratory study of water immobilization for improved oil recovery  

Microsoft Academic Search

In most oil reservoirs, injected water tends to follow the paths taken by previously injected water. If some of the paths that have been water-swept could be immobilized, continued waterflooding might sweep new paths and yield more oil than traditional waterflooding. Laboratory experiments were conducted in which vertical unconsolidated cores were waterflooded to breakthrough. Various fractions of the water-swept volume

D. N. Meehan; D. E. Menzie; H. Crichiow

1977-01-01

297

The Study of Biobehavioral Rhythms in a Psychology Laboratory Course.  

ERIC Educational Resources Information Center

Reports on a laboratory experiment where students measured their heart rate, blood pressure, mood, alertness, and cognitive performance. Measures showed significant circadian heart rhythm variations. They were strongly correlated and peaked at different times. Discusses the implications of this and students' reactions to the experiment. (MJP)

Rowland, David L.; Wesselhoft, Theresa

1998-01-01

298

Waste management study: Process development at Lawrence Livermore National Laboratory  

SciTech Connect

This report presents the results of an evaluation of the present Toxic Waste Control Operations at the Lawrence Livermore National Laboratory, evaluates the technologies most applicable to the treatment of toxic and hazardous wastes and presents conceptual designs of processes for the installation of a new decontamination and waste treatment facility (DWTF) for future treatment of these wastes.

Not Available

1984-12-01

299

Laboratory Studies of Waves and Instabilities in Dusty Plasmas  

Microsoft Academic Search

Plasmas containing dust grains are found in many geophysical and astrophysical environments such as planetary rings, comet tails, noctilucent clouds, and the interstellar medium. `Dusty plasmas' are also present in devices used for plasma processing of semiconductors, in the exhaust of rocket engines, and in fusion devices. In typical laboratory experiments a micron-sized dust grain, having a mass of about

R. L. Merlino

1997-01-01

300

SHELTER COMPETITION BETWEEN TWO INVASIVE CRAYFISH SPECIES: A LABORATORY STUDY  

Microsoft Academic Search

Alien crayfishes represent a common threat to aquatic ecosystems. Their spread in Europe is leading to more frequent contacts between different invasive species populations. Shelter can be an important factor in the resulting interactions. A laboratory experiment was designed to analyse the competition for shelter in similarly sized males of two species that show an invasive behaviour in Spain, Pacifastacus

F. ALONSO; R. MARTÍNEZ

2006-01-01

301

Laboratory study of heavy oil recovery using polymer and solvent  

Microsoft Academic Search

An enhanced heavy oil recovery process using polymer and solvent was laboratory tested. The objectives were to increase oil recovery by (1) controlling bypassing of injected fluids through high permeability sands by the use of polymer and multivalent ion solutions, and (2) increasing oil mobility using solvent. Crude oils used for testing varied from 20.8 to 13.6° API gravity. Corresponding

G. D. Peterson; H. J. Lechtenberg; W. H. Caraway; G. L. Gates

1976-01-01

302

Study of Technology Transfer Arrangements for National Laboratories.  

National Technical Information Service (NTIS)

The transfer of technology to industrial partners and users is a complex task. The interactions between federal laboratories and industry and the market knowledge and ability to assess the needs of business users are beyond the charter of a federal labora...

R. C. Dorf K. K. F. Worthington

1987-01-01

303

Case Study: Steam System Improvements At Dupont Automotive Marshall Laboratory  

Microsoft Academic Search

Dupont's Marshall Laboratory is an automotive paint research and development facility in Philadelphia, Pennsylvania. The campus is comprised of several buildings that are served by Trigen-Philadelphia Energy Corporation's district steam loop. In 1996, Dupont management announced that it was considering moving the facility out of Philadelphia primarily due to the high operating cost compared to where they were considering relocating.

Andrew W. Larkin

2003-01-01

304

REGIONAL AIR POLLUTION STUDY: GAS CHROMATOGRAPHY LABORATORY OPERATION  

EPA Science Inventory

A gas chromatography laboratory was set up to analyze air samples collected in Teflon bags and stainless steel tanks. Samples were analyzed for total hydrocarbons, methane, CO, and C2-C10 hydrocarbons. A total of 455 samples, including replicates, were analyzed during the summer ...

305

Female Mate Choice in Rodents  

Microsoft Academic Search

\\u000a The selection of suitable mates from a pool of potential candidates is one of the most important choices a female rodent has\\u000a to make. It influences Darwinian fitness directly via the number of offspring produced but also by its viability, fertility,\\u000a and fecundity. Numerous mechanisms have evolved to ensure this fitness increase by maximizing reproductive success. They act\\u000a at various

Jörns Fickel; Alexandra Weyrich

306

Laboratory studies of heterogeneous processes relevant to Mars  

NASA Astrophysics Data System (ADS)

Heterogeneous (gas-surface) processes may play an important role in both the atmospheric and surface chemistry of Mars. Atmospheric species may be affected by the chemistry and physical properties of the planetary surface and the surface material may be affected by the components and properties of the atmosphere. In this thesis, several laboratory studies are described which experimentally investigate two types of atmosphere-surface systems likely to exist on Mars. First, experiments were performed to better understand the spatial and temporal variability of atmospheric methane (CH4) on Mars. Reported CH4 plumes in the atmosphere of Mars are difficult to explain using known chemical or physical processes. The observations imply a strong, present-day source and also a rapid yet unknown CH4 sink. We have investigated the potential role of mineral dust in CH4 variability. First, using a Knudsen cell capable of simulating Martian temperature and pressure conditions, we have studied the adsorption of CH4 to a Martian mineral analog as a function of temperature. An uptake coefficient was determined and then applied to the Martian surface-atmosphere system. Our results suggest that adsorption to soil grains could possibly affect the CH4 mixing ratio on a seasonal time scale especially at mid-latitude regions. Additionally, chemical oxidation of CH4 by oxidants thought to exist in the Martian regolith was studied. The Viking mission in the 1970's found Martian soil was able to oxidize complex organic compounds to CO 2. The identity of the oxidant is unknown, but has been proposed to be either hydrogen peroxide or perchlorate salts. We used a gas chromatograph to determine if simulated Mars soil containing these oxidants was able to oxidize CH4 to CO2. However, no CH4 was oxidized within the detection limit of the instrument and only an upper limit reaction coefficient could be reported. Even these upper limit values suggest CH 4 could not be removed from the Martian atmosphere rapidly enough to cause variability. We have also studied the interactions of another important trace gas on Mars, water vapor, with perchlorate, a highly deliquescent salt recently discovered in polar soil. A Raman microscope equipped with an environmental cell was used to study phase transitions of the salts. The relative humidity (RH) at which deliquescence (absorption of water vapor by the solid to become an aqueous solution) and efflorescence (crystallization of the aqueous solution) occur were determined as a function of temperature, hydration state and associated cation. We show that the deliquescence RH for perchlorate salts can be low (˜40% RH for anhydrous sodium perchlorate, for example). Thermodynamics can predict deliquescence; however, the kinetic inhibition of crystallization causes efflorescence to occur at much lower RH values than deliquescence which allows supersaturated salt solutions to exist in a metastable state. Based on the diurnal RH and temperature cycles on Mars, aqueous solutions could be stable or metastable for several hours a day at the Phoenix landing site. The astrobiological implications of potential liquid H2O on Mars are significant.

Gough, Raina V.

307

Modeling Natural Photic Entrainment in a Subterranean Rodent (Ctenomys aff. knighti), the Tuco-Tuco  

PubMed Central

Subterranean rodents spend most of the day inside underground tunnels, where there is little daily change in environmental variables. Our observations of tuco-tucos (Ctenomys aff. knighti) in a field enclosure indicated that these animals perceive the aboveground light-dark cycle by several bouts of light-exposure at irregular times during the light hours of the day. To assess whether such light-dark pattern acts as an entraining agent of the circadian clock, we first constructed in laboratory the Phase Response Curve for 1 h light-pulses (1000lux). Its shape is qualitatively similar to other curves reported in the literature and to our knowledge it is the first Phase Response Curve of a subterranean rodent. Computer simulations were performed with a non-linear limit-cycle oscillator subjected to a simple model of the light regimen experienced by tuco-tucos. Results showed that synchronization is achieved even by a simple regimen of a single daily light pulse scattered uniformly along the light hours of the day. Natural entrainment studies benefit from integrated laboratory, field and computational approaches.

Flores, Danilo E. F. L.; Tomotani, Barbara M.; Tachinardi, Patricia; Oda, Gisele A.; Valentinuzzi, Veronica S.

2013-01-01

308

Thieving rodents as substitute dispersers of megafaunal seeds  

PubMed Central

The Neotropics have many plant species that seem to be adapted for seed dispersal by megafauna that went extinct in the late Pleistocene. Given the crucial importance of seed dispersal for plant persistence, it remains a mystery how these plants have survived more than 10,000 y without their mutualist dispersers. Here we present support for the hypothesis that secondary seed dispersal by scatter-hoarding rodents has facilitated the persistence of these large-seeded species. We used miniature radio transmitters to track the dispersal of reputedly megafaunal seeds by Central American agoutis, which scatter-hoard seeds in shallow caches in the soil throughout the forest. We found that seeds were initially cached at mostly short distances and then quickly dug up again. However, rather than eating the recovered seeds, agoutis continued to move and recache the seeds, up to 36 times. Agoutis dispersed an estimated 35% of seeds for >100 m. An estimated 14% of the cached seeds survived to the next year, when a new fruit crop became available to the rodents. Serial video-monitoring of cached seeds revealed that the stepwise dispersal was caused by agoutis repeatedly stealing and recaching each other’s buried seeds. Although previous studies suggest that rodents are poor dispersers, we demonstrate that communities of rodents can in fact provide highly effective long-distance seed dispersal. Our findings suggest that thieving scatter-hoarding rodents could substitute for extinct megafaunal seed dispersers of tropical large-seeded trees.

Jansen, Patrick A.; Hirsch, Ben T.; Emsens, Willem-Jan; Zamora-Gutierrez, Veronica; Wikelski, Martin; Kays, Roland

2012-01-01

309

Identification of Rodent Homologs of Hepatitis C Virus and Pegiviruses  

PubMed Central

ABSTRACT Hepatitis C virus (HCV) and human pegivirus (HPgV or GB virus C) are globally distributed and infect 2 to 5% of the human population. The lack of tractable-animal models for these viruses, in particular for HCV, has hampered the study of infection, transmission, virulence, immunity, and pathogenesis. To address this challenge, we searched for homologous viruses in small mammals, including wild rodents. Here we report the discovery of several new hepaciviruses (HCV-like viruses) and pegiviruses (GB virus-like viruses) that infect wild rodents. Complete genome sequences were acquired for a rodent hepacivirus (RHV) found in Peromyscus maniculatus and a rodent pegivirus (RPgV) found in Neotoma albigula. Unique genomic features and phylogenetic analyses confirmed that these RHV and RPgV variants represent several novel virus species in the Hepacivirus and Pegivirus genera within the family Flaviviridae. The genetic diversity of the rodent hepaciviruses exceeded that observed for hepaciviruses infecting either humans or non-primates, leading to new insights into the origin, evolution, and host range of hepaciviruses. The presence of genes, encoded proteins, and translation elements homologous to those found in human hepaciviruses and pegiviruses suggests the potential for the development of new animal systems with which to model HCV pathogenesis, vaccine design, and treatment.

Kapoor, Amit; Simmonds, Peter; Scheel, Troels K. H.; Hjelle, Brian; Cullen, John M.; Burbelo, Peter D.; Chauhan, Lokendra V.; Duraisamy, Raja; Sanchez Leon, Maria; Jain, Komal; Vandegrift, Kurt Jason; Calisher, Charles H.; Rice, Charles M.; Lipkin, W. Ian

2013-01-01

310

Chemotherapy of Rodent Malaria.  

National Technical Information Service (NTIS)

This report summarises the activities of the chemotherapy group for 13 months (12 months initial contract plus one month's extension). The work reported on also includes results obtained from the completion of studies commenced in Liverpool under the cont...

W. Peters

1981-01-01

311

Laboratory Study of Nonlinearity and Fabric-Dependence of Till  

NASA Astrophysics Data System (ADS)

The nonlinearity of till deformation can be strong or slight, depending on initial fabric and on deformation conditions, as shown by our new experiments. Recent studies show that small-amplitude stress changes can trigger ice sheet motion and subglacial seismicity. Deformation in the subglacial region plays a key role in determining slip behavior, including creep, transient slip, stick-slip motion, and seismicity. However, progress in understanding these phenomena is limited by uncertainty in the rheology and frictional properties of glacial till. We report on detailed laboratory experiments to measure the creep and frictional constitutive properties of Caesar till sampled from the Scioto Lobe of the Laurentide Ice Sheet, collected in central Ohio. Experiments were conducted in a servo-controlled, double-direct shear apparatus with dried samples at normal stresses ranging from 50 kPa to 5 MPa. Till was sheared in a three-block arrangement in which two till layers are sandwiched between a central forcing block and two stationary blocks. We studied the effect of saturation, initial deformation fabric, stress history, and the boundary conditions of loading. The nominal frictional contact area is 100 cm2 and remains constant during shear. The layer thickness is 1 cm prior to shear. All blocks are grooved perpendicular to the shear direction to ensure that deformation occurs within the layer. Caesar till has a mean grain size of 0.60 mm, but lacks large amounts of silt and clay sized particles. Constant shear stress experiments were employed to study frictional creep. Creep was induced after an initial strain ranging from 0 to 1 to investigate the role of shear fabric on deformation. Experiments were started at 68% of the shear strength with stress increased in steps until tertiary creep occurred. Stress steps were either 2% or 5% of the shear strength. At 20 minutes and 40 minutes after a stress step, we calculated strain rate (slope of strain versus time over a two minute period). The stress exponent, n, was determined from the equation d?/dt = b?^{n}. Where ? is strain, ? shear stress, and b is a constant. We find that fabric has a significant effect on the rheology of till. With no initial strain, strain rates were 10^{- 6} to 10^{-5} s-1 with a corresponding stress exponent of n=6.8. At strains of 1, strain rates were slightly less (5x10-7 s-1) and increased rapidly as the stress approached the shear strength. Intermediate initial strains of 0.15, 0.25, 0.55, and 0.68 showed progressively decreasing strain rate with initial strain. In experiments with no fabric development corresponding to initial strain of less than 0.2, the stress exponent ranged from n~3 to n~7 until the onset of tertiary creep, which occurred immediately when stress reached 90% of the shear strength. For experiments with initial strain of greater than 0.2 the stress exponent is greater than 10 indicating plastic deformation. In cases of strong fabric development, strains larger than 0.6, the stress exponent was larger than 40 near the shear strength.

Rathbun, A. P.; Marone, C. J.; Alley, R. B.; Anandakrishnan, S.

2006-12-01

312

Laboratory studies of double-diffusive sources in closed regions  

Microsoft Academic Search

Various observations of layering and intrusions in the ocean strongly suggest that such structures and motions are produced and driven by horizontal and vertical gradients of temperature and salinity, i.e. by double-diffusive processes. Much of the laboratory work in this field has concentrated on one-dimensional problems, with the neglect of two-dimensional phenomena. The latter are addressed explicitly in the present

J. S. Turner; G. Veronis

2000-01-01

313

Useful laboratory tests for studying thrombogenesis in acute cardiac syndromes  

Microsoft Academic Search

We review laboratory tests that evaluate thrombogen- esis during acute coronary syndromes. These tests have been found to be valuable research tools in more clearly understanding the pathophysiology of acute coronary syndromes. In particular, we describe tissue factor, tissue factor pathway inhibitor, prothrombin fragment 1.2, thrombin-antithrombin complex, fibrinopeptide A, tissue plasminogen activator (t-PA), plasminogen acti- vator inhibitor-1 (PAI-1), t-PA-PAI complex,

Jawed Fareed; Debra A. Hoppensteadt; Fred Leya; Omer Iqbal; Helmut Wolf; Roger Bick

314

Sex differences in thermal nociception and morphine antinociception in rodents depend on genotype.  

PubMed

It has been appreciated for some time that the sexes can differ in their sensitivity to pain and its inhibition. Both the human and rodent literatures remain quite contentious, with many investigators failing to observe sex differences that others document clearly. Recent data from our laboratory have pointed to an interaction between sex and genotype in rodents, such that sex differences are observed in some strains but not others. However, these studies employed inbred mouse strains and are thus not directly relevant to existing data. We presently examined whether the observation of statistically significant sex differences in nociception and morphine antinociception might depend on the particular outbred rodent population chosen for study. Rats of both sexes and three common outbred strains were obtained from three suppliers (Long Evans, Simonsen; Sprague Dawley, Harlan; Wistar Kyoto, Taconic) and tested for nociceptive sensitivity on the 49 degrees C tail-withdrawal assay, and antinociception following morphine (1-10mg/kg, i.p.). In further studies, three outbred populations of mice (CD-1, Harlan; Swiss Webster, Harlan; Swiss Webster, Simonsen) were bred in our vivarium for several generations and tested for tail-withdrawal sensitivity and morphine antinociception (1-20male, and no significant difference. In a separate study in which the estrous cycle was tracked in female mice, we found evidence for an interaction between genotype and estrous phase relevant to morphine antinociception. However, estrous cyclicity did not explain the observed sex differences. These data are discussed with respect to the existing sex difference and pain literature, and also as they pertain to future investigations of these phenomena. PMID:10781697

Mogil, J S; Chesler, E J; Wilson, S G; Juraska, J M; Sternberg, W F

2000-05-01

315

Imaging Conditioned Fear Circuitry Using Awake Rodent fMRI  

PubMed Central

Functional magnetic resonance imaging (fMRI) is a powerful method for exploring emotional and cognitive brain responses in humans. However rodent fMRI has not previously been applied to the analysis of learned behaviour in awake animals, limiting its use as a translational tool. Here we have developed a novel paradigm for studying brain activation in awake rats responding to conditioned stimuli using fMRI. Using this method we show activation of the amygdala and related fear circuitry in response to a fear-conditioned stimulus and demonstrate that the magnitude of fear circuitry activation is increased following early life stress, a rodent model of affective disorders. This technique provides a new translatable method for testing environmental, genetic and pharmacological manipulations on emotional and cognitive processes in awake rodent models.

Brydges, Nichola M.; Whalley, Heather C.; Jansen, Maurits A.; Merrifield, Gavin D.; Wood, Emma R.; Lawrie, Stephen M.; Wynne, Sara-Madge; Day, Mark; Fleetwood-Walker, Sue; Steele, Douglas; Marshall, Ian; Hall, Jeremy; Holmes, Megan C.

2013-01-01

316

Unexpected primitive rodents in the Quaternary of Argentina  

NASA Astrophysics Data System (ADS)

This article describes the first fossils recorded in the Hernandarias Formation (Pleistocene) in Entre Ríos province (eastern Argentina). They are represented by three teeth assigned to the caviomorph rodents (Rodentia, Mammalia) Aenigmys diamantensis gen. et sp. nov. and Eumysops. To establish the phylogenetic affinities of the two most enigmatic teeth, their enamel microstructure was studied. Aenigmys diamantensis is considered the most primitive taxon of a clade formed by Dinomyidae Neoepiblemidae Heptaxodontidae. Evidence of the close relationships among these families also is presented herein. The new fossils reinforce previous hypotheses about the survival of primitive Brazilian taxa after their extinction in the Pampas and Patagonia of southern South America. They also show that the diversity of caviomorph rodents during the Quaternary was greater than supposed and that an important Quaternary extinction, not previously detected, affected several lineages. With the available evidence, it is not possible to determine if these rodents indicate a warm pulse or a particular biogeographic situation in Entre Ríos.

Vucetich, María G.; Vieytes, Emma C.; Verzi, Diego H.; Noriega, Jorge I.; Tonni, Eduardo P.

2005-10-01

317

New observations on urine contents in water-deprived Negev Desert rodents  

Microsoft Academic Search

In past studies, several rodent species of the murid subfamilies Gerbillinae and Cricetomyinae from the Namib Desert, when deprived of water, excreted allantoin precipitate in their urine. Shifting nitrogen excretion from urea to allantoin allows them to save much water. This phenomenon has not been reported in other rodents, and whether it is a trait that is common among desert

Carmi Korine; Itzick Vatnick; Ian G. van Tets; Berry Pinshow

2003-01-01

318

Late Miocene–Early Pliocene temperature estimates in Europe using rodents  

Microsoft Academic Search

Studies of mammal communities, and in particular of rodents, provide useful information on palaeoenvironments and palaeoclimates. Based on the relationship between species richness and climatic parameters, we propose three models, using arvicolines, murines or sigmodontines in order to quantify past temperatures. Based on rodents, temperatures are estimated here for Late Miocene–Early Pliocene (MN 9 to MN 15) European faunas at

Sophie Montuire; Olivier Maridet; Serge Legendre

2006-01-01

319

THE USE OF CHEMICALS TO CONTROL FIELD RODENTS AND OTHER PREDATORS. AGRICULTURAL CHEMICALS TECHNOLOGY, NUMBER 5.  

ERIC Educational Resources Information Center

|THE PURPOSE OF THIS GUIDE IS TO ASSIST TEACHERS IN PREPARING POST-SECONDARY STUDENTS FOR AGRICULTURAL CHEMICAL OCCUPATIONS. IT IS ONE OF A SERIES OF MODULES DEVELOPED BY A NATIONAL TASK FORCE ON THE BASIS OF DATA FROM STATE STUDIES. SECTIONS ARE (1) USE OF CHEMICALS FOR RODENT CONTROL AND ERADICATION, (2) TERMINOLOGY AND COMPUTATIONS, (3) RODENT

Ohio State Univ., Columbus. Center for Vocational and Technical Education.

320

Prospects for biological control of rodent populations.  

PubMed

Pathogens and predatory animals are the main agents used for the biological control of rodents. The pathogens that have been used are of the genus Salmonella; none is rodent-specific and all can cause severe infection in man and domestic animals. Furthermore, rodents frequently develop immunity to, and become carriers of, these organisms, and there is little to commend their use, except in lightly populated areas where control is infrequently applied. The relationships of five predator species with their rodent prey have been examined. The monitor lizard, mongoose, and ferret were for different reasons found to be unsatisfactory, and there is not yet sufficient evidence to warrant further releases of the Japanese weasel. Domestic and feral cats control rodents well in some situations but only after some other agent has removed a large part of the rodent population. PMID:4587482

Wodzicki, K

1973-01-01

321

Prospects for biological control of rodent populations*  

PubMed Central

Pathogens and predatory animals are the main agents used for the biological control of rodents. The pathogens that have been used are of the genus Salmonella; none is rodent-specific and all can cause severe infection in man and domestic animals. Furthermore, rodents frequently develop immunity to, and become carriers of, these organisms, and there is little to commend their use, except in lightly populated areas where control is infrequently applied. The relationships of five predator species with their rodent prey have been examined. The monitor lizard, mongoose, and ferret were for different reasons found to be unsatisfactory, and there is not yet sufficient evidence to warrant further releases of the Japanese weasel. Domestic and feral cats control rodents well in some situations but only after some other agent has removed a large part of the rodent population.

Wodzicki, Kazimierz

1973-01-01

322

Synthesis of Polymerized Melanin by Cryptococcus neoformans in Infected Rodents  

Microsoft Academic Search

The ability of Cryptococcus neoformans to synthesize polymerized melanin in vitro has been associated with virulence, but it is unclear whether this fungus synthesizes polymerized melanin during infection. To study this question, we used two approaches: one involved the generation of monoclonal antibodies (MAbs) to melanin for use in immunohistochemical studies of C. neoformans-infected rodents, and the other sought to

ANGEL L. ROSAS; JOSHUA D. NOSANCHUK; MARTA FELDMESSER; GARY M. COX; HENRY C. MCDADE; ARTURO CASADEVALL

2000-01-01

323

Oxidation of atmospheric reduced sulphur compounds: perspective from laboratory studies  

PubMed Central

Results of laboratory experiments which address the course of the OH + DMS (dimethyl sulphide) reaction in the atmosphere are presented. It is shown that OH reacts via a complex sequence of reactions to produce CH3S and other products, and argued that NO3 is unlikely to be an important oxidizer of DMS in the marine boundary layer (MBL) because it is very efficiently taken up by water droplets. A simplified mechanism for the oxidation of DMS in the troposphere is presented. This mechanism explains some of the field observations on the end products of DMS oxidation and their variations with temperature.

Ravishankara, A. R.; Rudich, Y.; Talukdar, R.; Barone, S. B.

1997-01-01

324

Evaluation of bioaccumulation using in vivo laboratory and field studies.  

PubMed

A primary consideration in the evaluation of chemicals is the potential for substances to be absorbed and retained in an organism's tissues (i.e., bioaccumulated) at concentrations sufficient to pose health concerns. Substances that exhibit properties that enable biomagnification in the food chain (i.e., amplification of tissue concentrations at successive trophic levels) are of particular concern due to the elevated long-term exposures these substances pose to higher trophic organisms, including humans. Historically, biomarkers of in vivo chemical exposure (e.g., eggshell thinning, bill deformities) retrospectively led to the identification of such compounds, which were later categorized as persistent organic pollutants. Today, multiple bioaccumulation metrics are available to quantitatively assess the bioaccumulation potential of new and existing chemicals and identify substances that, upon or before environmental release, may be characterized as persistent organic pollutants. This paper reviews the various in vivo measurement approaches that can be used to assess the bioaccumulation of chemicals in aquatic or terrestrial species using laboratory-exposed, field-deployed, or collected organisms. Important issues associated with laboratory measurements of bioaccumulation include appropriate test species selection, test chemical dosing methods, exposure duration, and chemical and statistical analyses. Measuring bioaccumulation at a particular field site requires consideration of which test species to use and whether to examine natural populations or to use field-deployed populations. Both laboratory and field methods also require reliable determination of chemical concentrations in exposure media of interest (i.e., water, sediment, food or prey, etc.), accumulated body residues, or both. The advantages and disadvantages of various laboratory and field bioaccumulation metrics for assessing biomagnification potential in aquatic or terrestrial food chains are discussed. Guidance is provided on how to consider the uncertainty in these metrics and develop a weight-of-evidence evaluation that supports technically sound and consistent persistent organic pollutant and persistent, bioaccumulative, and toxic chemical identification. Based on the bioaccumulation information shared in 8 draft risk profiles submitted for review under the United Nations Stockholm Convention, recommendations are given for the information that is most critical to aid transparency and consistency in decision making. PMID:19552500

Weisbrod, Annie V; Woodburn, Kent B; Koelmans, Albert A; Parkerton, Thomas F; McElroy, Anne E; Borgå, Katrine

2009-10-01

325

Ethanol Drinking in Rodents  

PubMed Central

Many studies have used voluntary ethanol consumption by animals to assess the influence of genetic and environmental manipulations on ethanol drinking. However, the relationship between home cage ethanol consumption and more formal assessments of ethanol-reinforced behavior using operant and instrumental conditioning procedures is not always clear. The present review attempted to evaluate whether there are consistent correlations between mouse and rat home cage ethanol drinking on the one hand, and either operant oral self-administration (OSA), conditioned taste aversion (CTA) or conditioned place preference (CPP) with ethanol on the other. We also review literature on intravenous ethanol self-administration (IVSA). To collect data, we evaluated a range of genetic manipulations that can change both genes and ethanol drinking behavior including selective breeding, transgenic and knock-out models, and inbred and recombinant inbred strain panels. For a genetic model to be included in the analysis, there had to be published data resulting in differences on home cage drinking and data for at least one of the other behavioral measures. A consistent, positive correlation was observed between ethanol drinking and OSA, suggesting that instrumental behavior is closely genetically related to consummatory and ingestive behavior directed at ethanol. A negative correlation was observed between CTA and drinking, suggesting that ethanol’s aversive actions may limit oral consumption of ethanol. A more modest, positive relationship was observed between drinking and CPP, and there were not enough studies available to determine a relationship with IVSA. That some consistent outcomes were observed between widely disparate behavioral procedures and genetic populations may increase confidence in the validity of findings from these assays. These findings may also have important implications when researchers decide which phenotypes to use in measuring alcohol-reward relevant behaviors in novel animal models.

Green, Alexis S.; Grahame, Nicholas J.

2008-01-01

326

Synanthropic rodents as possible reservoirs of shigatoxigenic Escherichia coli strains  

PubMed Central

Shigatoxigenic Escherichia coli (STEC) strains are worldwide zoonotic pathogen responsible for different cases of human disease including hemolytic uremic syndrome (HUS). Transmission of STEC to humans occurs through the consumption of food and water contaminated by faeces of carriers and by person-to-person contact. The objective of this study was two-fold: (1) to investigate whether synanthropic rodents are possible reservoirs of STEC in the urban area and (2) whether a particular genus out of synanthropic rodent is the principal carrier of STEC. One hundred and forty-five rodents were captured in Buenos Aires City. Screening for stx1/stx2 and rfbO157 was done by PCR from the confluence zone. STEC isolates were further characterized with biochemical tests by standard methods. Additional virulence factors (eae, ehxA, and saa) were also determined by PCR. Forty-one of the rodents were necropsied and sample of kidney and small and large intestine were taken for histopathological diagnosis. The samples sections were stained with hematoxylin-eosin, and observed by light microscopy to evaluate the systemic involvement of these species in natural infections. STEC was isolated from seven out of 27 suspect animals at screening. The following genotypes were found in the STEC strains: stx1/stx2/ehxA (1), stx2 (4), stx2/ehxA (1), stx2/ehxA/eae (1). Neither gross nor microscopic lesions compatible with those produced by Shiga toxin were observed in the studied organs of necropsied rodents. The bivariate analysis including the 145 rodent's data showed that the isolation of STEC is associated positively to Rattus genus. This synanthropic species may play a role in the transmissibility of the agent thus being a risk to the susceptible population. Their control should be included specifically in actions to dismiss the contamination of food and water by STEC in the urban area, as additional strategies for epidemiological control.

Blanco Crivelli, Ximena; Rumi, Maria V.; Carfagnini, Julio C.; Degregorio, Osvaldo; Bentancor, Adriana B.

2012-01-01

327

Prediction of rodent carcinogenicity for 30 chemicals.  

PubMed Central

Predictions of carcinogenic activity are made for 30 chemicals currently being assessed for rodent carcinogenicity by the U.S. National Toxicology Program. The predictions are based upon the chemical structure, the anticipated or reported mutagenicity, and the reported sub-chronic toxicity of each chemical. It is predicted that 13 chemicals will be noncarcinogenic to rodents, that 7 will be genotoxic carcinogens, and that 10 may show some evidence of presumed nongenotoxic rodent carcinogenesis.

Ashby, J

1996-01-01

328

Prediction of rodent carcinogenicity for 30 chemicals  

SciTech Connect

Predictions of carcinogenic activity are made for 30 chemicals currently being assessed for rodent carcinogenicity by the U.S. National Toxicology Program. The predictions are based upon the chemical structure, the anticipated or reported mutagenicity, and the reported sub-chronic toxicity of each chemical. It is predicted that 13 chemicals will be noncarcinogenic to rodents, that 7 will be genotoxic carcinogens, and that 10 may show some evidence of presumed nongenotoxic rodent carcinogenesis. 3 refs., 1 fig.

Ashby, J. [Zeneca Central Toxicology Lab., Cheshire (United Kingdom)

1996-10-01

329

Industrywide studies report: a walk through survey of Ross Laboratories (Division of Abbott Laboratories), Columbus, Ohio. [Ethylene oxide  

SciTech Connect

A walk-through survey was conducted at Ross Laboratories, a Division of Abbott Laboratories, Columbus, Ohio in August, 1985. The purpose of the survey was to determine the feasibility of including the facility in a NIOSH industry wide mortality/industrial hygiene survey of ethylene oxide. The facility produced infant formula and infant related products, including nipples. The company had a full time nurse on the first and second shifts. A physician was available on a contract basis. New employees were given preemployment physicals. Employees received annual physicals until 1982 after which they became optional. The physicals did not include any components relating to ethylene-oxide exposure. The authors conclude that the personnel records are not adequate to identify a cohort of exposed individuals at the facility. The facility will not be included in the NIOSH study.

Greife, A.; Steenland, K.

1985-10-02

330

Dynamics of pyroclastic density currents studied using scaled laboratory experiments  

NASA Astrophysics Data System (ADS)

We performed a set of scaled laboratory experiments to simulate pyroclastic density currents (PDCs) using dilute mixtures of warm talc powder in air. The experiments were designed to evaluate the effects of topography and bed roughness on current runout, buoyancy reversal and liftoff, and mass partitioning into buoyant plumes. The densimetric and thermal Richardson, Froude, Stokes, and settling numbers for our experiments match those of PDCs and the laboratory currents are fully turbulent, although the experiments have lower Reynolds numbers than PDCs, thus our experiments are dynamically similar to natural currents. Comparisons of currents traversing flat topography or encountering barriers shows that runout distance is not significantly reduced for currents that traverse barriers with height less than 1.5 times the current thickness, but currents do not pass taller barriers. Buoyancy reversals occur in most currents, resulting in liftoff and generation of a buoyant plume. Liftoff occurs near the maximum runout distance for currents traveling over flat topography, but is focused near or above barriers for currents that encounter barriers. Notably, plume formation above barriers can result in reversal of flow direction downstream of the obstruction as portions of the current flow back and feed the rising plume. Greater than half of the initial particle mass composing the density currents usually partitions into the buoyant plumes; that fraction is greater for currents that liftoff closer to the source, thus topographic barriers increase mass partitioning from currents into buoyant plumes.

Manga, M.; Andrews, B.

2011-12-01

331

Laboratory studies of pyroclastic flows that interact with topography  

NASA Astrophysics Data System (ADS)

We performed a set of scaled laboratory experiments to simulate pyroclastic density currents (PDCs) using dilute mixtures of warm talc powder in air. The experiments were designed to evaluate the effects of topography on current runout, buoyancy reversal and liftoff, and mass partitioning into buoyant plumes. The densimetric and thermal Richardson, Froude, Stokes, and settling numbers for our experiments match those of PDCs and the laboratory currents are fully turbulent, although the experiments have lower Reynolds numbers than PDCs, thus our experiments are dynamically similar to natural currents. Comparisons of currents traversing flat topography or encountering barriers shows that runout distance is not significantly reduced for currents that traverse barriers with height less than 1.5 times the current thickness, but currents do not pass taller barriers. Buoyancy reversals occur in most currents, resulting in liftoff and generation of a buoyant plume. Liftoff occurs near the maximum runout distance for currents traveling over flat topography, but is focused near or above barriers for currents that encounter barriers. Notably, plume formation above barriers can result in reversal of flow direction downstream of the obstruction as portions of the current flow back and feed the rising plume. Greater than half of the initial particle mass composing the density currents usually partitions into the buoyant plumes; that fraction is greater for currents that liftoff closer to the source, thus topographic barriers increase mass partitioning from currents into buoyant plumes.

Andrews, B.; Manga, M.

2012-04-01

332

A laboratory and clinical study of Trevalon denture base material.  

PubMed

Trevalon is a denture base material which can be cured by three basic alternative curing cycles, thus providing a choice of processing technique which can be selected to suit laboratory or clinical needs. The flexibility of working properties is probably due to the interaction between on the one hand, the high molecular weight of the powder and on the other hand, the particle size distribution which are important factors influencing the doughing time (14 min), working time (40 min) and the exothermic reaction. The effect of each curing cycle upon the following properties of the material was investigated; dimensional accuracy, Young's modulus, modulus of rupture, impact resistance, water sorption, indentation resistance, creep and transverse bend behaviour. The particle size and molecular weight distribution of the powder were also evaluated. A clinical investigation of Trevalon was carried out by constructing complete dentures for a sample of patients, divided into three groups, each group having dentures processed by one of the three alternative curing cycles. Although some laboratory tests demonstrated that there were statistically significant differences between specimen bases, no clinical differences were recorded between dentures 1 year after construction. PMID:6957571

Murphy, W M; Huggett, R; Handley, R W

1982-09-01

333

Estrogen and Hippocampal Plasticity in Rodent Models  

PubMed Central

Accumulating evidence indicates that ovarian hormones regulate a wide variety of non-reproductive functions in the central nervous system by interacting with several molecular and cellular processes. A growing animal literature using both adult and aged rodent models indicates that 17?-estradiol, the most potent of the biologically relevant estrogens, facilitates some forms of learning and memory, in particular those that involve hippocampal-dependent tasks. A recently developed triple-transgenic mouse (3xTg-AD) has been widely used as an animal model of Alzheimer's disease, as this mouse exhibits an age-related and progressive neuropathological phenotype that includes both plaque and tangle pathology mainly restricted to hippocampus, amygdala and cerebral cortex. In this report, we examine recent studies that compare the effects of ovarian hormones on synaptic transmission and synaptic plasticity in adult and aged rodents. A better understanding of the non-reproductive functions of ovarian hormones has far-reaching implications for hormone therapy to maintain health and function within the nervous system throughout aging.

Foy, Michael R.; Baudry, Michel; Brinton, Roberta Diaz; Thompson, Richard F.

2010-01-01

334

Molecular evolution of the nuclear von Willebrand factor gene in mammals and the phylogeny of rodents.  

PubMed

Nucleotide sequences of exon 28 of the von Willebrand Factor (vWF) were analyzed for a representative sampling of rodent families and eutherian orders, with one marsupial sequence as outgroup. The aim of this study was to test if inclusion of an increased taxonomic diversity in molecular analyses would shed light on three uncertainties concerning rodent phylogeny: (1) relationships between rodent families, (2) Rodentia monophyly, and (3) the sister group relationship of rodents and lagomorphs. The results did not give evidence of any particular rodent pattern of molecular evolution relative to a general eutherian pattern. Base compositions and rates of evolution of vWF sequences of rodents were in the range of placental variation. The 10 rodent families studied here cluster in five clades: Hystricognathi, Sciuridae and Aplodontidae (Sciuroidea), Muridae, Dipodidae, and Gliridae. Among hystricognaths, the following conclusions are drawn: a single colonization event in South America by Caviomorpha, a paraphyly of Old World and New World porcupines, and an African origin for Old World porcupines. Despite a broader taxonomic sampling diversity, we did not obtain a robust answer to the question of Rodentia monophyly, but in the absence of any other alternative, we cannot reject the hypothesis of a single origin of rodents. Moreover, the phylogenetic position of Lagomorpha remains totally unsettled. PMID:10335651

Huchon, D; Catzeflis, F M; Douzery, E J

1999-05-01

335

A laboratory study of arched magnetic flux rope eruptions*  

NASA Astrophysics Data System (ADS)

Arched magnetic flux ropes (AMFRs) are arch-shaped twisted magnetic-structures that confine plasma and carry electrical current. Coronal loops and solar prominences are the main examples of AMFRs in the solar atmosphere. Solar AMFRs appear stable for long duration (several Alfven transit times) and then suddenly erupt due to occurrence of instabilities (e.g., kink instability). Solar AMFR eruptions have been frequently observed to evolve into more energetic events such as solar flares and coronal mass ejections. A laboratory plasma experiment has been constructed to simulate such eruptions in an ambient magnetized plasma. The laboratory AMFR (n ~ 1019 m-3 , Te ~ 10 eV, B ~ 1 kG, L ~ 0.5 m) is produced using an annular LaB6 cathode and an annular anode mounted on two movable shafts in a vacuum chamber (1.0 m diameter, 4.5 m long). Each AMFR electrode has an electromagnet to produce a vacuum magnetic field along the curved axis of the AMFR. The vacuum chamber has an additional plasma source and electromagnets to produce the ambient magnetized plasma (n ~ 1018 m-3, Te ~ 4 eV, B ~ 25 G). Two laser beams (1064 nm, ~0.5 J/pulse) strike movable carbon targets placed behind the orifices of the electrodes to generate controlled plasma flows from the AMFR footpoints that drives the eruption. The experiment operates with a 0.5 Hz repetition rate and is highly reproducible. Thus, time evolution of the AMFR is recorded in three-dimensions with high spatio-temporal resolutions using movable diagnostic probes. Initial results on the dramatic eruption of an arched magnetic flux rope will be presented that demonstrate outward expansion of the AMFR, release of the AMFR plasma to the background, and excitation of magnetosonic waves in the ambient plasma. Reference: S. K. P. Tripathi and W. Gekelman, Phys. Rev. Lett. 105, 075005 *Work supported by US DOE and NSF Fast camera image of a laboratory AMFR. Laser generated flows can be seen emanating from the both footpoints of the AMFR.

Tripathi, S.; Gekelman, W. N.

2010-12-01

336

Laboratory Studies of Organic Compounds With Reflectance Spectroscopy  

NASA Astrophysics Data System (ADS)

In order to properly interpret reflectance spectra of any solar system surface from the earth to the Oort cloud, laboratory spectra of candidate materials for comparative analysis are needed. Although the common cosmochemical species (H2O, CO2, CO, NH3, and CH4) are well represented in the spectroscopic literature, comparatively little reflectance work has been done on organics from room to cryogenic temperatures at visible to near infrared wavelengths. Reflectance spectra not only enhance weak or unseen transmission features, they are also more analogous to spectra obtained by spacecraft that are imaging such bodies as giant planet moons, kuiper belt objects, centaurs, comets and asteroids, as well as remote sensing of the earth. The USGS Spectroscopy Laboratory is measuring reflectance spectra of organic compounds from room to cryogenic temperatures over the spectral range of 0.35 to 15.5 microns. This region encompasses the fundamental absorptions and many overtones and combinations of C, H, O, and N molecular bonds. Because most organic compounds belong to families whose members have similar structure and composition, individual species identification within a narrow wavelength range may be ambiguous. By measuring spectral reflectance of the pure laboratory samples from the visible through the near and mid-infrared, absorption bands unique to each can be observed, cataloged, and compared to planetary reflectance data. We present here spectra of organic compounds belonging to five families: the alkanes, alkenes, alkynes, aromatics, and cyanides. Common to all of these are the deep C-H stretch fundamental absorptions, which shift shortward from 3.35+ microns in alkanes to 3.25+ microns in aromatics, to 3.2+ microns in alkenes, and down to 3.0+ microns in alkynes. Mid-IR absorptions due to C-H bending deformations at 6.8+ and 7.2+ microns are also identified. In the near infrared these stretching and bending fundamentals yield a diagnostic set of combination absorptions at approximately 2.3 microns, as well as the first C-H stretching overtones at 1.6 to 1.7 microns, and even the second stretching overtones at 1.2+ microns. Additionally, the spectral properties of these organic materials have applications to remote sensing of terrestrial environments, including hazardous waste and disaster site characterization.

Curchin, J. M.; Clark, R. N.; Hoefen, T. M.

2007-12-01

337

Transfection of rodent malaria parasites.  

PubMed

Gene manipulation is an invaluable tool to investigate and understand the biology of an organism. Although this technology has been applied to both the human and rodent malarial parasites (RMP), Plasmodium berghei in particular offers a more robust system due to a higher and more efficient transformation rate. Here, we describe a comprehensive transfection and selection protocol using P. berghei including a variant negative selection protocol administering 5-fluorocytosine to the animals in drinking water. Additionally, we discuss and assess the latest advances in gene manipulation technologies developed in RMP to gain a better understanding of Plasmodium biology. PMID:22990773

Philip, Nisha; Orr, Rachael; Waters, Andrew P

2013-01-01

338

Urban resident attitudes toward rodents, rodent control products, and environmental effects  

EPA Science Inventory

Rodent control in urban areas can result in the inadvertent mortality of non-target species (e.g., bobcats). However, there is little detailed information about rodent control practices of urban residents. Our objective was to evaluate urban rodent control behaviors in two area...

339

Optical depolarization from turbulent convective flow: A laboratory study  

NASA Astrophysics Data System (ADS)

In an effort to investigate the role of turbulence in near-forward scattering, laboratory measurements of scattering on turbulent flow were carried out in a Rayleigh-Benard convective tank. Particle Image Velocimetry and profiling thermistor temperature measurements are used to characterize the turbulent flow through determination of the large scale flow features, turbulent kinetic energy dissipation rates, and thermal dissipation rates. Polarized diffractometer measurements allow for determination of the turbulence-induced depolarization rate, which is comparable to that observed with polarimetric lidar. Measurements were made over a range of turbulent strengths, with Rayleigh number between 108 and 3*109, and with turbulent parameters corresponding to those characteristic of the oceanic mixed layer. Results show that the turbulence-induced depolarization rate is indirectly proportional to the strength of the turbulent flow, suggesting that light beam depolarization from turbulent flow may contain useful information regarding the smallest length scales of turbulent flow.

Woods, Sarah F.

340

Study of polyelectrolytes for Los Alamos National Laboratory. Final report  

SciTech Connect

To assess the safety of a potential radioactive waste repository, analysis of the fluid solution containing low levels of activity need to be performed. In some cases, the radioactivity would be so weak (3--30 pCi/L) that the solution must be concentrated for measurement. For this purpose, Los Alamos National Laboratory scientists are synthesizing some water soluble polyelectrolytes, which, because they are strong complexing agents for inorganic cations, can concentrate the radioelements in solution. To assist in characterization of these polyelectrolytes, the author has performed experiments to determine physico-chemical constants, such as pKa values and stability constants. The complexation constants between both polyelectrolytes and europium were determined by two methods: solvent extraction and ion exchange. Results are presented.

Labonne, N. [Florida State Univ., Tallahassee, FL (United States)

1994-11-01

341

Space weathering on Mercury: Laboratory studies and modelling  

NASA Astrophysics Data System (ADS)

Mercury is one of the most mysterious objects in the Solar System. To date, Mercury has been visited only by the Mariner 10 spacecraft, which imaged less than half of the surface. The inner planet is now the target of two missions: NASA's MESSENGER and the European Space Agency's BepiColombo. One of the key measurement goals of both missions is global mapping of the surface composition. However, it is known from lunar research that regolith exposed to the space environment evolves in a way that obscures the mineralogical information otherwise derived from reflectance spectroscopy. This evolution process (space weathering), is the result of micrometeorite bombardment and solar wind sputtering, during which ferrous iron in lunar minerals is reduced to metallic iron. Such processes are also expected to operate on other airless bodies, including Mercury. This thesis focuses on the use of laboratory simulations of space weathering, with particular emphasis on Mercury. A pulsed laser facility was established, capable of simulating impacts into regolith analogues at varying temperatures. A variety of analytical techniques were then evaluated to quantify the amount of metallic iron produced and its size distribution; space weathering is critically dependent on both of these parameters. Nearly all of the optical and magnetic properties observed in lunar space weathering were also observed in laboratory analyses. Of the techniques used, measurements of magnetic susceptibility proved extremely useful. These were rapid and non-destructive measurements, and were diagnostic of the ferromagnetic iron produced during weathering. In addition, multi-frequency or temperature-dependent measurements could readily detect the very fine superparamagnetic particles that modified the reflectance spectra. Having demonstrated the importance of these measurements, the possibility of including a magnetic susceptibility sensor on future planetary landers was investigated; this would provide useful data constraining mineralogy and regolith maturity for very low mass and power resources.

Bentley, Mark Stephen

342

Molecular imaging in neuroscience research with small-animal PET in rodents.  

PubMed

Cognitive neuroscience, which studies the biological basis of mental processes, widely uses neuroimaging technologies like functional magnetic resonance imaging and positron emission tomography (PET) to study the human brain. Small laboratory animals, like rodents, are commonly used in brain research and provide abundant models of human brain diseases. The development of high-resolution small-animal PET and various radiotracers together with sophisticated methods for analyzing functional brain imaging data have accelerated research on brain function and neurotransmitter release during behavioral tasks in rodents. In this review, we first summarize advances in the methodology of cognitive research brought about by the development of sophisticated methods for whole-brain imaging analysis and improvements in neuroimaging protocols. Then, we discuss basic mechanisms related to metabolic changes and the expression of neurotransmitters in various brain areas during task-induced neural activity. In particular, we discuss glucose metabolism imaging and brain receptor imaging for various receptor systems. Finally, we discuss the current status and future perspectives. Mechanisms of neurotransmitter expression will probably become an increasingly important field of study in the future, leading to more collaboration between investigators in fields such as computational and theoretical neuroscience. PMID:21241748

Xi, Wang; Tian, Mei; Zhang, Hong

2011-01-15

343

An Exploratory Study of Objective Attainment in the Divergent Physics Laboratory.  

ERIC Educational Resources Information Center

Students enrolled in the introductory physics laboratory at New Mexico State University participated in this study. A stated set of objectives, developed by Dr. John M. Fowler of the Commission on College Physics, was used in the laboratory. This study attempted to measure student achievement based on the use of these objectives as opposed to the…

Lerch, Robert Donald

344

A Comparison of Science Laboratory Classrooms in Asia, Australia, South Pacific and USA: An International Study.  

ERIC Educational Resources Information Center

|This study attempted to compare the science laboratory learning environments of secondary schools across both developed and developing countries (Australia, Brunei, Cook Islands, Fiji, Papua New Guinea, Singapore, Solomon Islands, Tonga, Tuvalu, United States, Vanuatu, and Western Samoa). The study used a version of the Science Laboratory

Giddings, Geoffrey; Waldrip, Bruce G.

345

Laboratory study of the adsorption of organic and inorganic compounds by coal  

Microsoft Academic Search

A laboratory study of the adsorption of organic and inorganic compounds by coal was conducted by the University of Caifornia Lawrence Livermore Laboratory to elucidate earlier experiments on ground-water contamination by underground coal gasification. In those studies, there was a continuous decrease in the concentrations of all pollutants, including phenolic compounds, aromatic hydrocarons, cyanide and metal ions (e.g., Ni, Zn,

1979-01-01

346

A Comparison of Science Laboratory Classrooms in Asia, Australia, South Pacific and USA: An International Study.  

ERIC Educational Resources Information Center

This study attempted to compare the science laboratory learning environments of secondary schools across both developed and developing countries (Australia, Brunei, Cook Islands, Fiji, Papua New Guinea, Singapore, Solomon Islands, Tonga, Tuvalu, United States, Vanuatu, and Western Samoa). The study used a version of the Science Laboratory Learning…

Giddings, Geoffrey; Waldrip, Bruce G.

347

Seven Principles of Instructional Content Design for a Remote Laboratory: A Case Study on ERRL  

ERIC Educational Resources Information Center

|This paper discusses the results of a study of the requirements for developing a remote radio frequency (RF) laboratory for electrical engineering students. It investigates students' preferred usage of the technical content of a state-of-the-art RF laboratory. The results of this study are compared to previous findings, which dealt with other…

Cagiltay, N. E.; Aydin, E.; Aydin, C. C.; Kara, A.; Alexandru, M.

2011-01-01

348

Handheld digital equipment for weight composite distress paradigms: new considerations and for rapid documentation and intervention of rodent populations.  

PubMed

Animal care in the third millennium will require a melding of scientific and humane interests to achieve optimal care of genetically engineered mice and to expedite scientific and medical advances by using these mammals. Undoubtedly, rodent patients present certain difficulties for those who wish to assess their daily well-being and to contribute to efficient and successful scientific discovery. High-density housing, large experimental groups, and low-lux room lighting makes the application of large-animal care standards to rodents seem daunting to researchers and veterinary care programs. In addition, great variability in training and experience among those responsible for the direct application of humane care to rodents exists. Most of the direct animal care in small animal facilities occurs in decentralized locales by personnel who have completed obligatory but relatively minimal animal care training. Examples of personnel in this category include postdoctoral fellows, junior-level scientists, summer students, and assistant laboratory animal technologists. Some programs even use the husbandry staff to perform health checks of high-risk populations on a daily basis. For this reason, the extrapolation of performance-based intervention in rodent care is difficult to apply practically. Early efforts to enhance humane outcome in rodents have been published by scientists and veterinarians and are largely directed at singular endpoints, such as weight loss and declining temperatures, in specific models. Scientists often are reluctant to accept such standards because of concern about premature intervention or variability between scorers and to reservations regarding a lack of procedural likeness with their proposed study. This paper highlights a digital method for melding current advanced animal scoring standards using palm pilot user-friendly methods that account for composite weight scoring, behavioral or physiologic attributes, and interventions. Information is rapidly downloaded and results in quick storage of large rodent population monitoring. This minimizes interpretative variability between caregivers and greater standardization of procedures. These considerations facilitate the rapid diagnosis of outliers and make possible intervention that streamlines the delivery of humane care to large experimental populations. PMID:11451389

Hampshire, V

2001-07-01

349

Interspecific competition in small rodents: from populations to individuals  

Microsoft Academic Search

The role of interspecific competition in shaping animal and plant communities has formed one of the major issues in ecology for decades. Small mammals, mainly rodents, have been among the model systems used for research on interspecific competition. Most studies within small mammal systems in the past have examined effects of competition on population attributes such as on population size,

Jana A. Eccard; Hannu Ylönen

2003-01-01

350

Coxiella burnetii in rodents on Heixiazi Island at the Sino-Russian border.  

PubMed

This work is a molecular epidemiologic study to detect the incidence of Coxiella burnetii in rodents on Heixiazi Island at the Sino-Russian border of Heilongjiang Province. Liver tissues were extracted and processed to test the incidence of C. burnetii infection using polymerase chain reaction analysis. In total, 18% (66 of 370) of rodents tested positive for infection. The results of logistic regression analysis indicated that infection with C. burnetii was associated significantly with weight and month of capture, and infection was found in all rodent species that were observed; there was no significant difference of sex on the infection of C. burnetii. Though phylogenetic analysis disclosed heterogeneity in the nucleotide sequences isolated from the island rodents, the majority of observed strains were among the most common strains found worldwide. This is the first report on the incidence of C. burnetii in rodents on Heixiazi Island at the Sino-Russian border. PMID:23382172

Liu, Lijuan; Baoliang, Xu; Yingqun, Fu; Ming, Li; Yu, Yang; Yong, Hou; Shasha, Wang; Manxia, Hu; Tianyu, Guo; Chao, Jiang; Xiaohong, Sun; Jing, Wang

2013-02-04

351

Laboratory Studies of Waves and Instabilities in Dusty Plasmas  

NASA Astrophysics Data System (ADS)

Plasmas containing dust grains are found in many geophysical and astrophysical environments such as planetary rings, comet tails, noctilucent clouds, and the interstellar medium. `Dusty plasmas' are also present in devices used for plasma processing of semiconductors, in the exhaust of rocket engines, and in fusion devices. In typical laboratory experiments a micron-sized dust grain, having a mass of about a trillion times that of a positive ion, will acquire a negative charge corresponding to a few thousand electrons. The presence of this massive and highly charged species alters the conventional quasineutrality condition in an electron-ion plasma, modifying both the propagation characteristics and instability thresholds of the usual plasma wave modes. It also gives rise to new very low frequency `dust modes,' directly associated with the dust grain dynamics.(N. N. Rao, P. K. Shukla, and M. Y. Yu, Planet. Space Sci. 38), 543 (1990).^,(N. D'Angelo, Planet. Space Sci. 38), 1143 (1990). In this tutorial talk, I will first discuss some of the basic physics of waves in dusty plasmas followed by a presentation of our laboratory investigations of the effect of negatively charged dust on ion-acoustic waves(A. Barkan, N. D'Angelo, and R. L. Merlino, Planet. Space Sci. 44), 239 (1996). and current-driven electrostatic ion-cyclotron waves.(A. Barkan, N. D'Angelo, and R. L. Merlino Planet. Space Sci. 43) 905 (1995). These experiments were performed in a single-ended Q-machine which incorporates a rotating dust dispersal system(W. Xu, B. Song, R. L. Merlino, and N. D'Angelo, Rev. Sci. Instrum. 63), 5266 (1992). for introducing dust into the plasma. I will then describe our observations of `dust acoustic' waves performed in a DC glow discharge in which negatively charged dust grains are electrostatically confined.(C. Thompson, A. Barkan, N. D'Angelo, and R. L. Merlino, Phys. Plasmas 4), 2331 (1997). Dust-acoustic waves are low-frequency ion-acoustic waves (tens of Hz) in which the inertia is provided by the heavy negatively charged dust grains and the tension is provided by the ion and electron pressures. These waves are visually observable in the light scattered by the dust. A video recording of these waves will be shown as well as measurements of the dispersion relation.

Merlino, R. L.

1997-11-01

352

Laboratory Studies of Ammonia Ices Relevant to the Jovian Atmosphere  

NASA Astrophysics Data System (ADS)

Ammonia ice condensation and cloud formation microphysics are topics of relevance for understanding the atmospheres of the giant planets. Ammonia ices are also considered important components of the icy satellites found in the outer solar system, and are thought to play an important role in their geological activity. Although observational evidence and thermochemical models suggest ammonia clouds in the Jovian atmosphere should be ubiquitous, less than only 1% of Jupiter's atmosphere appears covered by spectrally identifiable ammonia clouds, with a clear preference in turbulent regions.1,2 The paradox of the rather scarce spectroscopic signatures of ammonia clouds and their appearance in turbulent regions suggests that the nascent ammonia clouds may undergo processing that modifies their spectroscopic properties. No relevant laboratory experimental results are available to resolve this problem. Two possible sources of processing that have been suggested in the literature include photochemical solid-state modification (''tanning'') and coating of ammonia particles by other substances present in the stratospheric haze.2,3 We are performing laboratory investigations with the objective to provide information on the photophysical and chemical processes that control the optical properties of the Jovian ammonia clouds. In the experiments, thin ice films of ammonia are coated with organic molecules, such as saturated and aromatic hydrocarbons, and characterized by infrared spectroscopy. Preliminary results indicate suppression of the ammonia absorption feature at 2.7 ? m by a thin layer of hydrocarbons. The implications for the spectral signatures of ammonia clouds in the atmospheres of Jupiter and Saturn will be discussed. Funding from the NSF Planetary Astronomy Program under grant AST-0206270 is gratefully acknowledged. The participation of Rhiannon Meharchand and Christina Baer was made possible by the NSF Research Experiences for Undergraduates Program under grant PHY-0353745. 1. S. K. Atreya and A.-S. Wong, Eos. Trans. 84(46), Fall. Meet. Suppl., Abstract A12A-0072 (2003), and references therein. 2. K. H. Baines, R. W. Carlson, and L. W. Kamp, Icarus 159, 74 (2002). 3. A.-S. Wong, Y. L. Yung, and A. J. Friedson, Geophys. Res. Lett. 30, 1447 (2003).

Meharchand, R. T.; Boulter, J. E.; Baer, C. E.; Kalogerakis, K. S.

2004-12-01

353

Population cycles in small rodents.  

PubMed

We conclude that population fluctuations in Microtus in southern Indiana are produced by a syndrome of changes in birth and death rates similar to that found in other species of voles and lemmings. The mechanisms which cause the changes in birth and death rates are demolished by fencing the population so that no dispersal can occur. Dispersal thus seems critical for population regulation in Microtus. Because most dispersal occurs during the increase phase of the population cycle and there is little dispersal during the decline phase, dispersal is not directly related to population density. Hence the quality of dispersing animals must be important, and we have found one case of increased dispersal tendency by one genotype. The failure of population regulation of Microtus in enclosed areas requires an explanation by any hypothesis attempting to explain population cycles in small rodents. It might be suggested that the fence changed the predation pressure on the enclosed populations. However, the fence was only 2 feet (0.6 meter) high and did not stop the entrance of foxes, weasels, shrews, or avian predators. A striking feature was that the habitat in the enclosures quickly recovered from complete devastation by the start of the spring growing season. Obviously the habitat and food quality were sufficient to support Microtus populations of abnormally high densities, and recovery of the habitat was sufficiently quick that the introduction of new animals to these enclosed areas resulted in another population explosion. Finally, hypotheses of population regulation by social stress must account for the finding that Microtus can exist at densities several times greater than normal without "stress" taking an obvious toll. We hypothesize that the prevention of dispersal changes the quality of the populations in the enclosures in comparison to those outside the fence. Voles forced to remain in an overcrowded fenced population do not suffer high mortality rates and continue to reproduce at abnormally high densities until starvation overtakes them. The initial behavioral interactions associated with crowding do not seem sufficient to cause voles to die in situ. What happens to animals during the population decline? Our studies have not answered this question. The animals did not appear to disperse, but it is possible that the method we used to measure dispersal (movement into a vacant habitat) missed a large segment of dispersing voles which did not remain in the vacant area but kept on moving. Perhaps the dispersal during the increase phase of the population cycle is a colonization type of dispersal, and the animals taking part in it are likely to stay in a new habitat, while during the population decline dispersal is a pathological response to high density, and the animals are not attracted to settling even in a vacant habitat. The alternative to this suggestion is that animals are dying in situ during the decline because of physiological or genetically determined behavioral stress. Thus the fencing of a population prevents the change in rates of survival and reproduction, from high rates in the increase phase to low rates in the decline phase, and the fenced populations resemble "mouse plagues." A possible explanation is that the differential dispersal of animals during the phase of increase causes the quality of the voles remaining at peak densities in wild populations to be different from the quality of voles at much higher densities in enclosures. Increased sensitivity to density in Microtus could cause the decline of wild populations at densities lower than those reached by fenced populations in which selection through dispersal has been prevented. Fencing might also alter the social interactions among Microtus in other ways that are not understood. The analysis of colonizing species by MacArthur and Wilson (27) can be applied to our studies of dispersal in populations of Microtus. Groups of organisms with good dispersal and colonizing ability are called r strategists because they have high reproductive po

Krebs, C J; Gaines, M S; Keller, B L; Myers, J H; Tamarin, R H

1973-01-01

354

LABORATORY STUDIES OF HOMING ORIENTATION IN THE EASTERN RED-SPOTTED NEWT, NOTOPHTHALMUS VIRIDESCENS  

Microsoft Academic Search

SUMMARY The orientation behaviour of adult male eastern red-spotted newts {Notophthal- mus viridescens) was studied in laboratory tests. Newts were collected from ponds located 10-30 km from the laboratory, and housed in water-filled, all-glass aquaria located in a greenhouse or outdoors adjacent to the laboratory building. The aquaria were aligned on the magnetic north-south axis. Newts were tested in a

JOHN B. PHILLIPS

1987-01-01

355

Rodent Control: Seal Up! Trap Up! Clean Up!  

MedlinePLUS

... can be found at http://www.usa.gov . Rodents Worldwide, rats and mice spread over 35 diseases. These diseases can be spread to humans directly, through handling of rodents, through contact with rodent feces, urine, or saliva, ...

356

Laboratory studies of molecular growth in the Titan ionosphere.  

PubMed

Experimental simulations of the initial steps of the ion-molecule reactions occurring in the ionosphere of Titan were performed at the synchrotron source Elettra in Italy. The measurements consisted of irradiating gas mixtures with a monochromatic photon beam, from the methane ionization threshold at 12.6 eV, up to and beyond the molecular nitrogen dissociative ionization threshold at 24.3 eV. Three gas mixtures of increasing complexity were used: N(2)/CH(4) (0.96/0.04), N(2)/CH(4)/C(2)H(2) (0.96/0.04/0.001), and N(2)/CH(4)/C(2)H(2)/C(2)H(4) (0.96/0.04/0.001/0.001). The resulting ions were detected with a high-resolution (1 T) FT-ICR mass spectrometer as a function of time and VUV photon energy. In order to interpret the experimental results, a Titan ionospheric model was adapted to the laboratory conditions. This model had previously allowed the identification of the ions detected in the Titan upper atmosphere by the ion neutral mass spectrometer (INMS) onboard the Cassini spacecraft. Comparison between observed and modeled ion densities validates the kinetic model (reactions, rate constants, product branching ratios) for the primary steps of molecular growth. It also reveals differences that we attribute to an intense surface chemistry. This result implies that heterogeneous chemistry on aerosols might efficiently produce HCN and NH(3) in the Titan upper atmosphere. PMID:19769328

Thissen, Roland; Vuitton, Veronique; Lavvas, Panayotis; Lemaire, Joel; Dehon, Christophe; Dutuit, Odile; Smith, Mark A; Turchini, Stefano; Catone, Daniele; Yelle, Roger V; Pernot, Pascal; Somogyi, Arpad; Coreno, Marcello

2009-10-22

357

The role of phylogeny in desert rodent community assembly.  

PubMed

Recent advances in molecular genetics and phylogenetic reconstruction have the potential to transform ecology by providing new insights into the historical evolution of ecological communities. This study by Stevens and collaborators complements decades of previous research on desert rodents, by combining data from a field study and a phylogenetic tree for Mojave Desert rodents to address patterns and processes of community assembly. The number of coexisting rodent species is positively correlated, and the average phylogenetic distance among these species is negatively correlated with perennial plant species richness. As rodent species diversity increases along a gradient of increasing environmental heterogeneity, communities are composed of increasingly related species: there is a consistent pattern of phylogenetic structure from over-dispersed through random to clumped. I discuss this pattern in the light of complementary results of previous studies. This paper is noteworthy for calling attention to still unanswered questions about how the historical events of speciation, colonization, extinction, and trait evolution and their relationship to past climates and vegetation have given rise to current patterns of community organization. PMID:22324970

Brown, James H

2012-03-01

358

Robust Reproducible Resting State Networks in the Awake Rodent Brain  

PubMed Central

Resting state networks (RSNs) have been studied extensively with functional MRI in humans in health and disease to reflect brain function in the un-stimulated state as well as reveal how the brain is altered with disease. Rodent models of disease have been used comprehensively to understand the biology of the disease as well as in the development of new therapies. RSN reported studies in rodents, however, are few, and most studies are performed with anesthetized rodents that might alter networks and differ from their non-anesthetized state. Acquiring RSN data in the awake rodent avoids the issues of anesthesia effects on brain function. Using high field fMRI we determined RSNs in awake rats using an independent component analysis (ICA) approach, however, ICA analysis can produce a large number of components, some with biological relevance (networks). We further have applied a novel method to determine networks that are robust and reproducible among all the components found with ICA. This analysis indicates that 7 networks are robust and reproducible in the rat and their putative role is discussed.

Becerra, Lino; Pendse, Gautam; Chang, Pei-Ching; Bishop, James; Borsook, David

2011-01-01

359

Effects of fat and protein levels on foraging preferences of tannin in scatter-hoarding rodents.  

PubMed

Both as consumers and dispersers of seeds, scatter-hoarding rodents often play an important role in the reproductive ecology of many plant species. However, the seeds of many plant species contain tannins, which are a diverse group of water-soluble phenolic compounds that have a high affinity for proteins. The amount of tannins in seeds is expected to affect rodent foraging preferences because of their major impact on rodent physiology and survival. However, variable results have been obtained in studies that evaluated the effects of tannin on rodent foraging behavior. Hence, in this study, we aimed to explain these inconsistent results and proposed that a combination of seed traits might be important in rodent foraging behavior, because it is difficult to distinguish between the effects of individual traits on rodent foraging behavior and the interactions among them. By using a novel artificial seed system, we manipulated seed tannin and fat/protein levels to examine directly the univariate effects of each component on the seed preferences of free-ranging forest rats (Apodemus latronum and Apodemus chevrieri) during the behavioral process of scatter hoarding. Our results showed that both tannin and fat/protein had significant effects on rodent foraging behavior. Although only a few interactive effects of tannin and fat/protein were recorded, higher concentrations of both fat and protein could attenuate the exclusion of seeds with higher tannin concentrations by rodents, thus influencing seed fate. Furthermore, aside from the concentrations of tannin, fat, and protein, numerous other traits of plant seeds may also influence rodent foraging behavior. We suggest that by clarifying rodent foraging preferences, a better understanding of the evolution of plant seed traits may be obtained because of their strong potential for selective pressure. PMID:22808217

Wang, Bo; Chen, Jin

2012-07-10

360

Next-generation sequencing for rodent barcoding: species identification from fresh, degraded and environmental samples.  

PubMed

Rodentia is the most diverse order among mammals, with more than 2,000 species currently described. Most of the time, species assignation is so difficult based on morphological data solely that identifying rodents at the specific level corresponds to a real challenge. In this study, we compared the applicability of 100 bp mini-barcodes from cytochrome b and cytochrome c oxidase 1 genes to enable rodent species identification. Based on GenBank sequence datasets of 115 rodent species, a 136 bp fragment of cytochrome b was selected as the most discriminatory mini-barcode, and rodent universal primers surrounding this fragment were designed. The efficacy of this new molecular tool was assessed on 946 samples including rodent tissues, feces, museum samples and feces/pellets from predators known to ingest rodents. Utilizing next-generation sequencing technologies able to sequence mixes of DNA, 1,140 amplicons were tagged, multiplexed and sequenced together in one single 454 GS-FLX run. Our method was initially validated on a reference sample set including 265 clearly identified rodent tissues, corresponding to 103 different species. Following validation, 85.6% of 555 rodent samples from Europe, Asia and Africa whose species identity was unknown were able to be identified using the BLASTN program and GenBank reference sequences. In addition, our method proved effective even on degraded rodent DNA samples: 91.8% and 75.9% of samples from feces and museum specimens respectively were correctly identified. Finally, we succeeded in determining the diet of 66.7% of the investigated carnivores from their feces and 81.8% of owls from their pellets. Non-rodent species were also identified, suggesting that our method is sensitive enough to investigate complete predator diets. This study demonstrates how this molecular identification method combined with high-throughput sequencing can open new realms of possibilities in achieving fast, accurate and inexpensive species identification. PMID:23144869

Galan, Maxime; Pagès, Marie; Cosson, Jean-François

2012-11-07

361

A Case-Study of Assessment in Materials Laboratory  

NSDL National Science Digital Library

Materials engineering students are often ill prepared to enter the workforce upon graduation. While students master the content knowledge they often lack critical skills for success. Our industry feedback of internship students indicates weakness in the areas of: technical writing, critical thinking, professional attitude & teamwork, analysis, reasoning and decision making. We have examined the effectiveness of new teaching and assessment methods in the Materials Laboratory classes. Through our use of new materials and assessment instruments support our thesis that will lead to student improvement in the defined areas of weakness. The integration of peer review strengthens teamwork and professional attitude both in the classroom and later in the students' professional lives. We have used interdisciplinary collaboration as another component to help develop analysis and reasoning skills by utilizing field trips to manufacturers who have quality control and project management programs. Our feedback system in scoring student reports will likely strengthen their technical writing skills. This works as follows: The group consists of one author and two to three reviewers every week. The roles alternate. The author sends a draft to the reviewers, who in turn review electronically and send the response to both the author and the instructor. This is to make sure the review process can also be graded and the author receives the material in time. The author now makes changes to the report and also responds to the reviewers suggestions in writing. The entire report is submitted to the instructor for assessment. The grades for the reviewers and the author alike, including the comments on the documents teach the students where strengths and weaknesses lie. We have exposed the students to professional engineering centers such as MAIC (Major Analytical Instrumentation Center) and PERC (Particle Engineering Research Center) where they develop better insight and can mirror an appropriate attitude in a professional environment.

Milz, Claudia; Carter, Rufus L.

2009-08-28

362

Laboratory Studies Of Wind Stress Over Surface Waves  

NASA Astrophysics Data System (ADS)

Simultaneous laboratory observations of wind speed, wind stress, and surfacewind-wave spectra are made under a variety of wind forcing patterns using cleanwater as well as water containing an artificial surfactant. Under typical experimentalconditions, more than half of the total stress is supported by the wave-induced stressrather than by the surface viscous stress. When the surfactant reduces the shortwind-wave spectra, the wind stress also decreases by as much as 20-30% at agiven wind speed. When the wind forcing is modulated in time, the wind stresstends to be higher under decreasing wind than under increasing wind at a givenwind speed, mainly because the response of short wind-wave spectra to varyingwind forcing is delayed in time. These examples clearly demonstrate that therelationship between the wind speed and the wind stress can be significantlymodified if the surface wave field is not in equilibrium with the wind forcing.Next, we examine whether the wind stress is estimated accurately if the wave-inducedstress by all surface wave components is explicitly evaluated by linear superpositionand is added to the surface viscous stress. It is assumed that the surface viscous stressis uniquely related to the wind speed, and that the wind input rate is determined by thelocal, reduced turbulent stress rather than the total stress. Our wind stress estimatesincluding the wave contributions agree well with observed wind stress values, evenif the surface wave field is away from its equilibrium with the wind in the presenceof surface films and/or under time-transient wind forcing. These observations stronglysuggest that the wind stress is accurately evaluated as a sum of the wave-induced stressand the surface viscous stress. At very high winds, our stress estimates tend to be lowerthan the observations. We suspect that this is because of the enhancement of wind stressover very steep (or breaking) short wind-waves.

Mete Uz, B.; Donelan, Mark A.; Hara, Tetsu; et al.

363

Exposure to rodents and rodent-borne viruses among persons with elevated occupational risk.  

PubMed

Persons who have frequent contact with rodents as part of their occupation may be at increased risk of exposure to rodent-borne viruses such as Sin Nombre virus (SNV), the agent of hantavirus pulmonary syndrome, and Whitewater Arroyo virus (WWA), a New World arenavirus. Eighty-one persons with possible occupational exposure to rodents completed questionnaires and provided specimens for serologic testing. Seventy-two participants reported handling rodents as part of their job. The mean total number of rodents handled during participants' careers was approximately 2200. IgG antibody to lymphocytic choriomeningitis virus was detected in serum from one (1.2%) participant. IgG antibody to SNV, WWA, and Amapari viruses was not detected in any of the serum specimens. Despite considerable exposure to rodents, participants did not have significant serological evidence of exposure to rodent-borne viruses. PMID:12391776

Fritz, Curtis L; Fulhorst, Charles F; Enge, Barryett; Winthrop, Kevin L; Glaser, Carol A; Vugia, Duc J

2002-10-01

364

Arenavirus antibody in rodents indigenous to coastal southern California.  

PubMed

The purpose of this study was to extend our knowledge on the geographic and natural rodent host ranges of New World arenaviruses in California. Sera from 1,094 sigmodontine and 112 murine rodents were tested for antibody against Whitewater Arroyo and Amapari viruses. Antibody was found in 55 (4.6%) of the 1,206 rodents: 4 from northwestern San Diego County, 3 from Los Angeles County, and 48 from Orange County. The antibody-positive rodents included 8 (7.8%) of 103 Neotoma fuscipes, 1 (0.6%) of 180 Neotoma lepida, 1 (3.1%) of 32 Peromyscus boylii, 8 (11.0%) of 73 Peromyscus californicus, 1 (1.2%) of 85 Peromyscus eremicus, 30 (8.5%) of 353 Peromyscus maniculatus, and 6 (2.2%) of 268 Reithrodontomys megalotis. This study provides the first evidence that New World arenaviruses occur in Los Angeles and Orange counties and northwestern San Diego County, and the first evidence that Peromyscus and Reithrodontomys species are naturally infected with New World arenaviruses. PMID:11289675

Bennett, S G; Milazzo, M L; Webb, J P; Fulhorst, C F

2000-05-01

365

Assessment of the use of selected rodents in ecological monitoring  

NASA Astrophysics Data System (ADS)

Rodents can be useful in detecting environmental impacts because they are easy to study (easy to capture and handle), they can occur in densities adequate for statistical analysis, and they are ecologically important. In this study the usefulness of rodent populations for ecological monitoring was investigated by examining the effect of variation on the possibility of detecting differences among populations of rodents on 10 trapping grids. The effects of sampling frequencies and dispersal on detecting differences in population parameters among grids was also investigated, as was the possibility of inferring population parameters from correlations with habitat data. Statistically significant differences as small as 4.3 Peromyscus maniculatus/ha were detected between grids. Of 10 populations, this comprised 12% of the highest-density population and 44% of the lowest-density population. Smaller and more differences among grids were found by examining only animals surviving from previous months. Dispersal confounds detection of direct impacts to populations, especially during the breeding season. Infrequent sampling fails to detect impacts that occur between sampling periods and will indicate impacts when observed changes result from natural variation. Correlations between population parameters and habitat variables exist but should only be used in predicting, not measuring, impacts. It is concluded that some rodent populations can be used in ecological monitoring. However, intensive sampling is required to account for variation and dispersal.

Douglass, Richard J.

1989-05-01

366

A study in test reproducibility between laboratories: Report of a Pseudomonas Working Party  

Microsoft Academic Search

The results are reported of a collaborative study in laboratories of 17 tests commonly used for pseudomonads, together with statistical analysis of the results in the form of analyses of variance. The studies involved 59 strains.

P. H. A. Sneath; Vera G. Collins

1974-01-01

367

The 1994 QUASIMEME Laboratory-Performance Studies: Polycyclic aromatic hydrocarbons (PAH) in standard solutions  

Microsoft Academic Search

A Laboratory Performance Study has been undertaken in order to assess and improve the measurement of concentrations of polycyclic aromatic hydrocarbons in standard solutions as part of the QUASIMEME (EU-Measurement and Testing) Project. Thirty-six laboratories were invited to participate and, of these, 25 returned data on 10 individual parent PAH compounds in two acetonitrile solutions. Techniques based upon both gas

Robin J Law; Jarle Klungsøyr

1996-01-01

368

Behavior of linear alkylbenzenesulfonate in different soils: a comparison between field and laboratory studies  

Microsoft Academic Search

The behavior of linear alkylbenzenesulfonate (LAS) in soils (i.e., degradation, percolation, and sorption) was investigated in field and laboratory tests. For this purpose sorption studies were carried out using Freundlich's method in order to obtain sorption constants. A prediction of sorption constants in characterized soils was possible using multiple regression and correlation methods. Degradation under laboratory conditions can faithfully be

N. Litz; H. W. Doering; M. Thiele; H. P. Blume

1987-01-01

369

Chlorobiphenyls and organochlorine pesticides in fish and sediments-three years of QUASIMEME laboratory performance studies  

Microsoft Academic Search

A series of five laboratory performance studies on the analysis of chlorobiphenyls (CBs) and organochlorine pesticides (OCPs) has been conducted within the three year EU-QUASIMEME (Quality Assurance of Information for Marine Environmental Monitoring in Europe) programme. The results of the Rounds 4 and 5 and the overall results of this programme are discussed. It was shown that laboratories with a

Jacob De Boer; David E. Wells

1997-01-01

370

Microbial transformations of substituted benzenes during infiltration of river water to groundwater: Laboratory column studies  

Microsoft Academic Search

The microbial transformations of dimethyl- and dichlorobenzenes have been studied in laboratory aquifer columns simulating saturated-flow conditions typical for a river water\\/groundwater infiltration system. The behavior of all compounds in the laboratory was qualitatively the same as that observed at a field site. Both dimethyl- and dichlorobenzenes were biotransformed under aerobic conditions, the dimethylbenzenes faster than the chlorinated analogues. Evidence

Elmar P. Kuhn; Patricia J. Colberg; Jerald L. Schnoor; Oskar Wanner; Alexander J. P. Zehnder; Rene P. Schwarzenbach

1985-01-01

371

Wellness Center use at Los Alamos National Laboratory: a descriptive study  

Microsoft Academic Search

This study describes employee participation during the first six months of the Los Alamos National Laboratory's corporate Wellness Program. We describe temporal patterns of use, preferred activities, frequency of use, and characteristics of employees participating in Wellness activities. Characteristics of Wellness participants are compared with characteristics of the Laboratory population. During this period the Wellness Center, a multi-use facility that

L. D. Wiggs; G. S. Wilkinson; C. Weber

1985-01-01

372

DUSEL CO2: A deep underground laboratory for geologic carbon sequestration studies  

Microsoft Academic Search

The objective of geologic sequestration of carbon dioxide as a greenhouse gas mitigation strategy is the long-term containment of CO2 in deep underground formations. To develop a sound understanding of geologic carbon sequestration, we will build a deep underground laboratory to study the processes of storing and trapping CO2, including the risks of unintended leakage. The laboratory will be part

C. A. Peters; P. F. Dobson; C. M. Oldenburg; G. Scherer; T. C. Onstott; J. T. Birkholzer; B. M. Freifeld; M. A. Celia; J. S. Wang; J. Prevost

2009-01-01

373

Organization of the doping control laboratory in the Athens 2004 Olympic Games: A case study  

Microsoft Academic Search

The organization with special attention to the Quality Assurance system of the Doping Control Laboratory of Athens (DCLA) implemented during the Athens 2004 Olympic Games is presented in this study. The DCLA has been accredited by the International Olympic Committee (IOC)\\/World Anti-Doping Agency (WADA) following the requirements of the WADA International Standard for Laboratories (ISL) and by ESYD, the greek

A. G. Fragkaki; I.-P. Leontiou; N. Kioukia-Fougia; M. Tsivou; M.-?. ?. Spyridaki; C. G. Georgakopoulos

2006-01-01

374

Usability of Windows Vista Firewall: A Laboratory User Study  

Microsoft Academic Search

In this project we conducted a user study of Microsoft Windows Vista Firewall: a lab study followed by a questionnaire to evaluate the usability of Vista's personal firewall. Our results show that the main problem with Windows Vista Firewall is that many users are unable to open the Advanced Management Interface of Windows Vista Firewall. Our overall impression was that

Robert Boeck; Pouyan Arjmandi; Ganapathy Viswanathan

375

Response of brown treesnakes to reduction of their rodent prey  

USGS Publications Warehouse

Trapping brown treesnakes (Boiga irregularis; BTS) with live-mouse (Mus domesticus) lures is the principal control technique for this invasive species on Guam. Lure-based trapping is also used on other islands as a precaution against undetected arrivals and in response to verified BTS sightings. However, the effectiveness of lure-based trapping on other islands is questionable, as it has yielded no BTS despite other evidence of their presence. Some evidence suggests that high rodent numbers may interfere with BTS control. To test the relationship between rodent abundance and snake trappability, we conducted a controlled, replicated field experiment incorporating a rodenticide treatment during a BTS mark-recapture study. Using open population modeling in Program MARK, we estimated BTS apparent survival and recapture probabilities. Rodent reduction increased BTS recapture probabilities by 52-65% in 2002 and 22-36% in 2003, and it decreased apparent survival by <1% both years. This appears to be the first published instance of manipulating wild prey to influence snake behavior. Rodent reduction may enhance detection and control of BTS with traps on Guam and other islands. It may also amplify the effectiveness of oral toxicants against BTS.

Gragg, J. E.; Rodda, G. H.; Savidge, J. A.; White, G. C.; Dean-Bradley, K.; Ellingson, A. R.

2007-01-01

376

Digestive responses of two omnivorous rodents ( Peromyscus maniculatus and P. alstoni ) feeding on epigeous fungus ( Russula occidentalis )  

Microsoft Academic Search

The sporocarps of hypogeous and epigeous fungi are important dietary items for forest dwelling rodents in temperate and tropical\\u000a forests throughout the world. However, results of some pioneering works have demonstrated that fungi cannot be considered\\u000a as nutritionally high-quality food items for some mycophagous small rodents. According to these studies, when mycophagous\\u000a rodents feed on fungus, they showed a minimal

T. D’Alva; C. Lara; A. Estrada-Torres; C. Castillo-Guevara

2007-01-01

377

Laboratory-Scale Study of Electrolytic Reduction of Uranium Oxides.  

National Technical Information Service (NTIS)

An exploratory study was undertaken to investigate potential improvements in the electrolytic reduction of uranium oxide to the metal. Potential advantages of the electrolytic procedure over existing chemical reduction processes are (1) lower operating te...

D. S. Poa L. Burris R. K. Steunenberg Z. Tomczuk

1988-01-01

378

Laboratory Study of Continuous Electrooxidation of Dilute Cyanide Wastes.  

National Technical Information Service (NTIS)

Feasibility of detoxifying dilute cyanide plating wastes by electrooxidation was studied. Because of the toxicity of cyanide to aquatic and animal life and its detrimental effect on the operation of sewage treatment plants, in-plant treatment of dilute cy...

J. J. Byerley K. Enns

1974-01-01

379

FIELD AND LABORATORY OPERATIONS REPORT FOR THE OREGON WETLANDS STUDY  

EPA Science Inventory

The Oregon Wetlands Study (OWS) was designed to provide detailed characterizations of natural, created, and restored freshwater wetlands which is located in the urban environment of Portland, Oregon. his document discusses training the elementary, middle and high school teachers ...

380

Laboratory Study of Gas-Fueled Condensing Furnaces.  

National Technical Information Service (NTIS)

The objective of the study was to determine if the direct measurement method of condensate collection that was developed during prior testing of a condensing boiler would be adequate for direct measurement of the condensate from gas fueled forced warm air...

E. R. Kweller R. A. Wise

1985-01-01

381

Global Inter-Laboratory Fecal Source Identification Methods Comparison Study  

EPA Science Inventory

Source tracking is key to identifying sources of fecal contamination for remediation as well as risk assessment. Previous intra- and inter-lab studies have investigated the performance of human and cow-associated source tracking markers, as well as library-dependent fecal source ...

382

Laboratory studies of the cosmic origins of organic chemistry  

NASA Astrophysics Data System (ADS)

We are constructing a novel merged-beams apparatus to study the cosmic origins of organic chemistry. With this, we plan to measure reaction rate coefficients of atomic C with molecular ions. Such chemical data is important for astrochemical models and observations of cosmic objects.

O'Connor, A. P.; Garrido, M.; Miller, K. A.; Urbain, X.; Savin, D. W.

2012-11-01

383

Tocotrienol supplementation in postmenopausal osteoporosis: evidence from a laboratory study  

PubMed Central

OBJECTIVE: Accelerated bone loss that occurs in postmenopausal women has been linked to oxidative stress and increased free radicals. We propose the use of antioxidants to prevent and reverse postmenopausal osteoporosis. This study aimed to examine the effects of tocotrienol, a vitamin E analog, on bone loss due to estrogen deficiency. Our previous study showed that tocotrienol increased the trabecular bone volume and trabecular number in ovariectomized rats. In the current study, we investigated the effects of tocotrienol supplementation on various biochemical parameters in a postmenopausal osteoporosis rat model. MATERIALS AND METHODS: A total of 32 female Wistar rats were randomly divided into four groups. The baseline group was sacrificed at the start of the study, and another group was sham operated. The remaining rats were ovariectomized and either given olive oil as a vehicle or treated with tocotrienol at a dose of 60 mg/kg body weight. After four weeks of treatment, blood was withdrawn for the measurement of interleukin-1 (IL1) and interleukin-6 (IL6) (bone resorbing cytokines), serum osteocalcin (a bone formation marker) and pyridinoline (a bone resorption marker). RESULTS: Tocotrienol supplementation in ovariectomized rats significantly reduced the levels of osteocalcin, IL1 and IL6. However, it did not alter the serum pyridinoline level. CONCLUSION: Tocotrienol prevented osteoporotic bone loss by reducing the high bone turnover rate associated with estrogen deficiency. Therefore, tocotrienol has the potential to be used as an anti-osteoporotic agent in postmenopausal women.

Muhammad, Norliza; Luke, Douglas Alwyn; Shuid, Ahmad Nazrun; Mohamed, Norazlina; Soelaiman, Ima Nirwana

2013-01-01

384

Laboratory Studies of Ammonia Leaching of Copper Ores. Volume I.  

National Technical Information Service (NTIS)

This report describes the results of ammonia leaching studies on sulfide and native copper ores of Michigan. Tests were performed on pure minerals to determine the kinetics of leaching and on ore samples to determine leaching rates, reagent losses, and di...

W. A. Hockings W. L. Freyberger

1975-01-01

385

Cyanobacterial Calcite Precipitation - Laboratory Study on Different Spatial Scales  

Microsoft Academic Search

Lacustrine calcite precipitation with sedimentation rates up to 1 mm per year can result in large carbonate deposits. Varved lake sediments high in calcite content are now intensively studied as high-resolution continental archives for environmental change. Especially in oligotrophic hardwater lakes, eukaryotic and prokaryotic picoplankton was found to be important in the overall process of calcite precipitation. Rates and mechanisms

M. Obst; D. Mavrocordatos; P. Gasser; M. Dittrich

2003-01-01

386

Laboratory Experiments to Study Radiocaesium Interaction in Organic Soils  

Microsoft Academic Search

The total concentration of a pollutant in a given environmental compartment is often used for risk assessment. However, the real impact of the pollutant also depends on its toxicity and mobility. In soils, pollutant mobility is strongly related to its interaction with the different sites. The mechanisms and dynamics of this interaction may be studied by adsorption and desorption approaches.

A. Rigol; M. Vidal; G. Rauret

2000-01-01

387

Clinical and laboratory studies into the pathogenesis of malacoplakia.  

PubMed Central

Three cases of malacoplakia are described. Electron microscopic studies revealed intact bacteria or bacteria in varying states of degradation within phagolysosomes of the malacoplakic macrophages. Michaelis-Gutmann bodies arise within the phagolysosomes. These findings suggest that the bacteria incorporated within the phagolysosomes persist as dense amorphous aggregates which later become encrusted with calcium phosphate crystals to form the laminated Michaelis-Gutmann bodies. Possible explanations for the unusual macrophage response in malacoplakia are: (1) infection with an unusual strain of bacteria, (2) an immunological abnormality affecting intracellular killing of organisms, and (3) an abnormality affecting intracellular digestion of organisms. In considering each of the possibilities, we have been unable to detect any unusual strain of infecting organisms in association with malacoplakia, and in vitro studies have revealed normal T lymphocyte response to mitogen and normal monocyte bactericidal capacity. According to the history, each patient had reason to have a compromised immune status; in only one, however, was this demonstrated. Images

Lewin, K J; Fair, W R; Steigbigel, R T; Winberg, C D; Droller, M J

1976-01-01

388

Review. Studying cumulative cultural evolution in the laboratory.  

PubMed

Cumulative cultural evolution is the term given to a particular kind of social learning, which allows for the accumulation of modifications over time, involving a ratchet-like effect where successful modifications are maintained until they can be improved upon. There has been great interest in the topic of cumulative cultural evolution from researchers from a wide variety of disciplines, but until recently there were no experimental studies of this phenomenon. Here, we describe our motivations for developing experimental methods for studying cumulative cultural evolution and review the results we have obtained using these techniques. The results that we describe have provided insights into understanding the outcomes of cultural processes at the population level. Our experiments show that cumulative cultural evolution can result in adaptive complexity in behaviour and can also produce convergence in behaviour. These findings lend support to ideas that some behaviours commonly attributed to natural selection and innate tendencies could in fact be shaped by cultural processes. PMID:18799419

Caldwell, Christine A; Millen, Ailsa E

2008-11-12

389

Automatic cortical thickness analysis on rodent brain  

NASA Astrophysics Data System (ADS)

Localized difference in the cortex is one of the most useful morphometric traits in human and animal brain studies. There are many tools and methods already developed to automatically measure and analyze cortical thickness for the human brain. However, these tools cannot be directly applied to rodent brains due to the different scales; even adult rodent brains are 50 to 100 times smaller than humans. This paper describes an algorithm for automatically measuring the cortical thickness of mouse and rat brains. The algorithm consists of three steps: segmentation, thickness measurement, and statistical analysis among experimental groups. The segmentation step provides the neocortex separation from other brain structures and thus is a preprocessing step for the thickness measurement. In the thickness measurement step, the thickness is computed by solving a Laplacian PDE and a transport equation. The Laplacian PDE first creates streamlines as an analogy of cortical columns; the transport equation computes the length of the streamlines. The result is stored as a thickness map over the neocortex surface. For the statistical analysis, it is important to sample thickness at corresponding points. This is achieved by the particle correspondence algorithm which minimizes entropy between dynamically moving sample points called particles. Since the computational cost of the correspondence algorithm may limit the number of corresponding points, we use thin-plate spline based interpolation to increase the number of corresponding sample points. As a driving application, we measured the thickness difference to assess the effects of adolescent intermittent ethanol exposure that persist into adulthood and performed t-test between the control and exposed rat groups. We found significantly differing regions in both hemispheres.

Lee, Joohwi; Ehlers, Cindy; Crews, Fulton; Niethammer, Marc; Budin, Francois; Paniagua, Beatriz; Sulik, Kathy; Johns, Josephine; Styner, Martin; Oguz, Ipek

2011-03-01

390

Brain/body relations among myomorph rodents.  

PubMed

The observed increase in brain size (E) with body size (P) 'from mouse to elephant' may be described by a power relation E = kPb, where b is near 2/3 or 3/4. That this reflects a single, strong interaction between brain and body evolution is challenged by two observations: (1) different species with the same body size may have markedly different brain sizes, and (2) the value of b at the species level is usually nearer 1/3 than 2/3. Furthermore, the idea that a bigger brain means greater versatility on the part of its owner makes a strong statement about such animals. We examined these notions by measuring cranial volumes of 1,480 skulls from 62 subspecies of cricetid and murid rodents. Values of k and b were obtained by computing a reduced major axis on E and P across all specimens (b = 0.693), and when specimens were partitioned by genus (b = 0.456) and subspecies level (b = 0.338). Thus, the overall slope of 7/10 is not a simple extension of the developmental rules at the subspecies level (b near 1/3) nor even at the genus level (b near 4/9). Rather, it may reflect the most likely path for an interbreeding population subjected to varying selective pressures on one or more correlated traits. Furthermore, among the rodents studied, folivorous subspecies averaged about 2/3 as much brain as granivorous, insectivorous or generalist subspecies of the same body weight. Also, Old World rats, which may be more versatile than wood rats, gained their competitive advantage despite having relatively smaller brains. PMID:3280099

Mann, M D; Glickman, S E; Towe, A L

1988-01-01

391

Internal temporal order in the circadian system of a dual-phasing rodent, the Octodon degus.  

PubMed

Daily rhythms in different biochemical and hematological variables have been widely described in either diurnal or nocturnal species, but so far no studies in the rhythms of these variables have been conducted in a dual-phasing species such as the degus. The Octodon degus is a rodent that has the ability to switch from diurnal to nocturnal activity under laboratory conditions in response to wheel-running availability. This species may help us discover whether a complete temporal order inversion occurs parallel to the inversion that has been observed in this rodent's activity pattern. The aim of the present study is to determine the phase relationships among 26 variables, including behavioral, physiological, biochemical, and hematological variables, during the day and at night, in diurnal and nocturnal degus chronotypes induced under controlled laboratory conditions through the availability of wheel running. A total of 39 male degus were individually housed under a 12:12 light-dark (LD) cycle, with free wheel-running access. Wheel-running activity (WRA) and body temperature (Tb) rhythms were recorded throughout the experiment. Melatonin, hematological, and biochemical variables were determined by means of blood samples obtained every 6?h (ZT1, ZT7, ZT13, and ZT19). In spite of great differences in WRA and Tb rhythms between nocturnal and diurnal degus, no such differences were observed in the temporal patterns of most of the biological variables analyzed for the two chronotypes. Variation was only found in plasma urea level and lymphocyte number. A slight delay in the phase of the melatonin rhythm was also observed. This study shows the internal temporal order of a dual-phasing mammal does not show a complete inversion in accordance with its activity and body temperature pattern; it would appear that the switching mechanism involved in the degu's nocturnalism is located downstream from the pacemaker. PMID:20854135

Otalora, Beatriz Baño; Vivanco, Pablo; Madariaga, Ana Maria; Madrid, Juan Antonio; Rol, Maria Angeles

2010-09-01

392

Laboratory study of Hall reconnection in partially ionized plasmas.  

PubMed

The effects of partial ionization (n(i) / n(n) ? 1%) on magnetic reconnection in the Hall regime have been studied systematically in the Magnetic Reconnection Experiment. It is shown that, when neutrals are added, the Hall quadrupole field pattern and thus electron flow are unchanged while the ion outflow speed is reduced due to ion-neutral drag. However, in contrast to theoretical predictions, the ion diffusion layer width does not change appreciably. Therefore, the total ion outflow flux and the normalized reconnection rate are reduced. PMID:23383799

Lawrence, Eric E; Ji, Hantao; Yamada, Masaaki; Yoo, Jongsoo

2013-01-02

393

Experimental Study of Driven Magnetic Relaxation in a Laboratory Plasma  

NASA Astrophysics Data System (ADS)

The physics goal of the Driven Relaxation Experiment (DRX) is to form and sustain simply-connected driven-relaxed plasmas above the first Jensen-Chu linear resonance of the force-free equation (where the first resonance is the ``flipped'' Rosenbluth- Bussac spheromak). As shown recently by Tang & Boozer (PRL, 2005), the linear resonances are regularized in partially relaxed systems, thus removing the energy barriers which have been thought to constrain relaxed states to exist only below the first resonance. DRX will apply an ``over-driven'' boundary condition at the coaxial gun source, with ?gun 30 m-1 3?1. The DRX power system (10 kV, 125 kJ) will form and sustain the ˜10 eV plasma for about 0.5 ms, which is about 10 Sweet-Parker reconnection times and sufficient for the plasma to reach a driven-relaxed steady-state. We will measure the 2D structure of the equilibrium magnetic field and compare it with the first several linear eigenmodes of the force-free equation, and subsequently study the k-spectrum of the magnetic energy as well as the dynamics of relaxation. Other topics we will study include magnetic flux amplification and the role of boundary elongation on equilibrium/stability. Better understanding of these issues could lead to new ideas for confinement configurations. This poster will provide an overview of DRX and first experimental data. Supported by the LANL LDRD Program.

Hsu, S.; Madziwa-Nussinov, T.; Sirajuddin, D.; Light, M.

2007-11-01

394

The Acetylene Laboratory IR Spectrum: New Quantitative Studies  

NASA Astrophysics Data System (ADS)

The acetylene molecule 12C2H2 shows numerous vibration - rotation bands throughout the IR spectrum. Vibrational levels of C2H2 are grouped into clusters almost regularly spaced every 700 cm-1, from the fundamental ?5 band, at 13.6 ?m, up to the visible. Several IR spectral regions where C2H2 bands occur have been extensively studied in the past years, mainly in order to obtain absolute individual line intensities and to improve spectroscopic databases as HITRAN or GEISA. This quantitative spectroscopy work is performed with the aid of Fourier transform interferometers to obtain absorption spectra, and using a multispectrum fitting procedure to retrieve line parameters from these spectra. For usual applications, a semi-empirical model based on the Herman-Wallis factor is used to generate line lists dedicated to spectroscopic databases. This poster gives a summary of all the spectral regions studied for acetylene 12C2H2, pointing out the current state of the spectroscopic databases HITRAN/GEISA. Works in progress (around 1300 cm-1) and in project (0 - 500 cm-1) will also be presented. Data available in the literature, or obtained in the recent works, have been compiled to set up line lists usable for applications and dedicated to databases. On the whole the number of transitions is twice compared to the actual HITRAN 2004 database plus the 2007 updates and is ranging from 700 to 9600 cm-1.

Jaccquemart, D.; Lacome, N.; Gomez, L.; Mandin, J.

2011-12-01

395

Bioremediation of TNT-contaminated soil: A laboratory study  

SciTech Connect

This research presented a bench-scale investigation of an innovative approach to land farming for the bioremediation of 2,4,6-trinitrotoluene (TNT)-contaminated soils. Molasses, which contains sugar, nitrogen, vitamins, and minerals, was used as cosubstrate and this process combines several advantages of conventional land farming with the use of molasses for the biological degradation of TNT and its derivatives. In the optimum treatment, contaminated soil was amended with shredded grass and managed in an operating cycle where it was alternatively flooded with a dilute molasses solution, then drained, passively aerated, and finally tilled when moisture conditions were optimum. Soil TNT concentrations in all treatments receiving molasses were reduced from approximately 4,000-mg/kg levels initially to less than 100 mg/kg in 12 months, and to less than 1 mg/kg in the optimum treatment in this same time. Concentrations of the primary metabolic intermediates and bacterial populations were also tracked. Radiolabeling studies confirmed that the biomass enhanced by the treatments could mineralize approximately 20% of [{sup 14C}] from a contaminant spike after 22 d. A shredded grass amendment in the optimum treatment was shown to increase moisture retention during aeration phases. The results of this bench-scale study are promising with regard to transferring the process to full-scale applications.

Widrig, D.L.; Boopathy, R.; Manning, J.F. Jr. [Argonne National Lab., IL (United States). Environmental Research Div.

1997-06-01

396

ENHANCED BIOREMEDIATION UTILIZING HYDROGEN PEROXIDE AS A SUPPLEMENTAL SOURCE OF OXYGEN: A LABORATORY AND FIELD STUDY  

EPA Science Inventory

Laboratory and field scale studies were conducted to investigate the feasibility of using hydrogen peroxide as a supplemental source of oxygen for bioremediation of an aviation gasoline fuel spill. Field samples of aviation gasoline contaminated aquifer material were artificially...

397

Potential for Occupational Exposure to Engineered Carbon-Based Nanomaterials in Environmental Laboratory Studies.  

National Technical Information Service (NTIS)

Background: The potential exists for laboratory personnel to be exposed to engineered carbonaceous nanomaterials (CNMs) in studies aimed at producing conditions similar to those found in natural surface waters (e.g., presence of natural organic matter (NO...

A. J. Kennedy D. R. Johnson J. A. Steevens M. M. Methner

2009-01-01

398

A Summary of the Development of Procedures for Laboratory Marine-Fouling Studies, Part 2.  

National Technical Information Service (NTIS)

The development of procedures for the rearing of barnacles in the laboratory and for the study of the settlement of these barnacles upon test surfaces under completely controlled conditions is discussed. Categories include: development of procedures for m...

1964-01-01

399

Laboratory Study to Compare the Effectiveness of Chemical Dispersants When Applied Dilute versus Neat.  

National Technical Information Service (NTIS)

The objective of the study was to determine if the application of chemical dispersants in a diluteform is likely to reduce significantly their effectiveness when compared with neat application. Aseries of large-scale laboratory tests were completed to eva...

2000-01-01

400

CHARACTERIZATION AND LABORATORY SOIL TREATABILITY STUDIES FOR CREOSOTE AND PENTACHLOROPHENOL SLUDGES AND CONTAMINATED SOIL  

EPA Science Inventory

Information is presented from characterization and laboratory treatability phases of a 3-phase study pertaining to on-site treatability potential of soils containing hazardous constituents from wood-treatment waste. Specific information includes: (1) literature assessment of soil...

401

Laboratories for the 21st Century: Case Studies, Molecular Foundry, Berkeley, California  

SciTech Connect

This case study provides information on the Molecular Foundry, which incorporates Labs21 principles in its design and construction. The design includes many of the strategies researched at Lawrence Berkeley Laboratory for energy efficient cleanroom and data centers.

Not Available

2010-11-01

402

ENVIRONMENTAL RADIOACTIVITY LABORATORY INTERCOMPARISON STUDIES PROGRAM: FISCAL YEAR 1980-1981  

EPA Science Inventory

The U.S. Environmental Protection Agency's intercomparison studies program for laboratories involved in environmental radiation measurements is described. The types of environmental samples distributed, the analyses required for each sample, the distribution schedule, and the sta...

403

Wellness Center Use at Los Alamos National Laboratory: A Descriptive Study.  

National Technical Information Service (NTIS)

This study describes employee participation during the first six months of the Los Alamos National Laboratory's corporate Wellness Program. We describe temporal patterns of use, preferred activities, frequency of use, and characteristics of employees part...

L. D. Wiggs G. S. Wilkinson C. Weber

1985-01-01

404

The impact of voluntary exercise on mental health in rodents: A neuroplasticity perspective  

Microsoft Academic Search

There is growing interest in the effects of voluntary wheel running activity on brain and behaviour in laboratory rodents and their implications to humans. Here, the major findings to date on the impact of exercise on mental health and diseases as well as the possible underlying neurobiological mechanisms are summarised. Several critical modulating factors on the neurobehavioural effects of wheel

Susanna Pietropaolo; Yan Sun; Ruixi Li; Corinne Brana; Joram Feldon; Benjamin K. Yee

2008-01-01

405

Potential detrimental effects of rodent viral infections on long-term experiments  

Microsoft Academic Search

Healthy animals are of paramount importance in obtaining meaningful, reliable scientific results. Viral infections of rodents often have a significant impact on various types of biomedical research. Laboratory animal specialists and researchers must be aware of the possible consequences associated with the use of infected animals. The objective of the paper is a discussion of the frequently encountered viral infections

G. Lussier

1988-01-01

406

Expression of Functional Leptin Receptors in Rodent Leydig Cells  

Microsoft Academic Search

Several studies indicate that the size of body fat stores and the circulating levels of the adipocyte-derived hormone leptin are able to influence the activity of the hypothalamic-pituitary-gonadal axis. The leptin-hypothalamic-pituitary-gonadal interactions have been mainly studied at the level of the central nervous system. In this study, we investigated the possibility that leptin may have direct effects on the rodent

MASSIMILIANO CAPRIO; ANDREA M. ISIDORI; ANNA R. CARTA; COSTANZO MORETTI; MARIA L. DUFAU; ANDREA FABBRI

1999-01-01

407

Effect of polymers on the imbibition process; A laboratory study  

SciTech Connect

Polymer flooding of fractured reservoirs is common. In water-wet fractured reservoirs, the primary recovery mechanism may be imbibition. This paper presents results of an experimental study investigating the effect of polymers on the imbibition process. Two sets of experiments, static and dynamic, were performed. The static experiments showed that the amounts of oil ultimately recovered by water and polymer-solution imbibition are practically equal. The rate of oil recovery by the polymer solutions, however, is always less than the rate with water. The dynamic experiments consisted of flooding oil-saturated fractured cores through the fractures. The oil-recovery behavior in these experiments depended not only on the rate of injected fluid imbibition from the fracture into the matrix blocks, but also on the operating injection rate and the efficiency of the injected fluid in displacing the oil in the fracture.

Ghedan, S.G. (University of Baghdad (IQ)); Poettmann, F.H. (Colorado School of Mines, CO (US))

1991-02-01

408

Laboratory study of magnetic reconnection generated Alfven waves. Final report  

SciTech Connect

This grant was funded through the Department of Energy, Office of Fusion Energy Junior Faculty Development Program. The grant funded the construction and start-up of the Articulated Large-area Plasma Helicon Array (alpha) experiment, and initial studies of Alfven wave propagation in helicon generated plasmas. The three year grant contract with Auburn University was terminated early (after two years) due to PI'S acceptance of a faculty position at New Mexico Tech. The project continues at New Mexico Tech under a different grant contract. The project met all of the second-year goals outlined in the proposal, and made progress toward meeting some of the third-year goals. The alpha facility was completed and multi-helicon operation was demonstrated. We have made initial measurements of Alfven waves in a helicon plasma source.

Watts, Christopher

2002-02-08

409

Laboratory Oscillator Strengths for Studies of Fe-group Abundances  

NASA Astrophysics Data System (ADS)

Recent decades have seen significant improvement in both the quantity and quality of available oscillator strengths for lines in the first and second spectra of many elements. These improvements have led to an increase in both the precision and accuracy of stellar abundance determinations, which in turn help elucidate outstanding questions in stellar astrophysics. One such outstanding question arises in the study of Fe-group nucleosynthesis in the early Universe. The observed trends of relative Fe-group abundances as a function of stellar metallicity (or age) are seriously discordant ( 1 dex) with Solar values and are difficult to replicate with nucleosynthetic yield calculations and models. These unexplained trends may result from some combination of residual errors in oscillator strengths, non-LTE/3D photospheric effects, and/or poorly understood nuclear physics. To help shed light on these outstanding questions we have returned our focus to the Fe-group atoms and ions, beginning with Mn I and Mn II. The goal of this ongoing work is to provide very accurate ( < ± 0.02 dex) oscillator strengths for Fe-group elements over a wide range of excitation potential for both neutral and singly ionized transitions such that both Saha and Boltzmann equilibrium assumptions can be tested. Abundance studies in metal poor giant and dwarf stars using these oscillator strengths indicate that while the resonance lines of the neutral yield Mn abundances that are too low compared to other neutral and ion transitions, the other transitions all yield consistent Mn abundances and [Mn/Fe] values of -0.70 ± 0.20 dex at metallicities of [Fe/H] = -2.5 ± 0.3. In metal-poor stars, the findings of subsolar Fe-group relative abundances appear to be robust. There is also a pressing need for Fe-group oscillator strengths for transitions in the H-band in support of APOGEE. Current work on Fe I will be described.

Den Hartog, Elizabeth

2012-05-01

410

COLLISIONAL DEBRIS AS LABORATORIES TO STUDY STAR FORMATION  

SciTech Connect

In this paper we address the question of whether star formation (SF) is driven by local processes or the large-scale environment. To do so, we investigate SF in collisional debris where the gravitational potential well and velocity gradients are shallower and compare our results with previous work on SF in noninteracting spiral and dwarf galaxies. We have performed multiwavelength spectroscopic and imaging observations (from the far-ultraviolet to the mid-infrared) of six interacting systems, identifying a total of 60 star-forming regions in their collision debris. Our analysis indicates that in these regions (1) the emission of the dust is at the expected level for their luminosity and metallicity, (2) the usual tracers of SFR display the typical trend and scatter found in classical star-forming regions, and (3) the extinction and metallicity are not the main parameters governing the scatter in the properties of intergalactic star-forming regions; age effects and variations in the number of stellar populations seem to play an important role. Our work suggests that local properties such as column density and dust content, rather than the large-scale environment seem to drive SF. This means that intergalactic star-forming regions can be used as a reliable tool to study SF.

Boquien, M. [University of Massachusetts, Department of Astronomy, LGRT-B 619E, Amherst, MA 01003 (United States); Duc, P.-A. [AIM-Unite Mixte de Recherche CEA-CNRS-Universite Paris VII-UMR no 7158 (France); Wu, Y. [Astronomy Department, Cornell University, Ithaca, NY 14853 (United States); Charmandaris, V. [Department of Physics, University of Crete, GR-71003, Heraklion (Greece); Lisenfeld, U. [Department de FIsica Teorica y del Cosmos, Universidad de Granada, Granada (Spain); Braine, J. [Observatoire de Bordeaux, UMR 5804, CNRS/INSU, B.P. 89, F-33270 Floirac (France); Brinks, E. [Centre for Astrophysics Research, University of Hertfordshire, College Lane, Hatfield AL10 9AB (United Kingdom); Iglesias-Paramo, J. [Instituto de AstrofIsica de AndalucIa, Camino Bajo de Huetor 50, 18008 Granada (Spain); Xu, C. K. [California Institute of Technology, MC 405-47, 1200 East California Boulevard, Pasadena, CA 91125 (United States)], E-mail: boquien@astro.umass.edu

2009-06-15

411

Detonation chemistry studies of energetic materials using laboratory scale samples  

SciTech Connect

We describe an apparatus by which the detonation products of an explosive can be identified and whose relative concentrations can be determined quantitatively. These measurements can be made on products that have been formed in less than one microsecond after the passage of the detonation wave. The technique is based on the rapid quenching of chemical reactions by virtue of the free expansion of the products into vacuum. Of course, products that have been formed over a longer period of time and under different pressure/temperature conditions can also be studied. Time resolved molecular-beam mass spectrometry is used, so that whether detonation occurred or not in forming the products can be determined. We describe optical techniques, principally Schlieren photographs, that also confirm detonation. We report measurements made on six standard explosives, PETN, RDX, HMX, HNS, TNT and TATB, and one research explosive, nitric oxide. For none of the standard explosives do we measure product distributions that agree with model predictions based on equilibrium assumptions. A computer model of the free expansion is described briefly and its importance to the interpretation of the data is emphasized. 16 refs., 13 figs.

Blais, N.C.; Greiner, N.R.; Fernandez, W.J.

1989-01-01

412

Laboratory study on the leaching potential of spent alkaline batteries.  

PubMed

Four different leaching tests were carried out with spent alkaline batteries as an attempt to quantify the environmental potential burdens associated with landfilling. The tests were performed in columns filled up with batteries either entire or cross-cut, using either deionized water or nitric acid solution as leachant. In a first set of tests, the NEN 7343 standard procedure was followed, with leachant circulating in open circuit from bottom to top through columns. These tests were extended to another leaching step where leachant percolated the columns in a closed loop process. Leachate solutions were periodically sampled and pH, conductivity, density, redox potential, sulphates, chlorides and heavy metals (As, Cd, Co, Cr, Cu, Fe, Hg, Mn, Ni, Pb, Sb, Tl and Zn) were determined in the samples. The results showed that the total amount of substances leached in tests with cross-cut batteries was higher than with entire ones; zinc and sulphates were the substances found the most in the leachate solutions. In general, the amount of substances dissolved in open circuit is higher than in closed loop due to the effect of solution saturation and the absence of fresh solution addition. Results were compared with metal contents in the batteries and with legal limits for acceptance in landfill (Decision 2003/33/CE and Decree-Law 152/2002). None of the metals were meaningfully dissolved comparatively to its content in the batteries, except Hg. Despite the differences in the experiment procedure used and the one stated in the legislation (mixing, contact time and granulometry), the comparison of results obtained with cross-cut batteries using deionized water with legal limits showed that batteries studied could be considered hazardous waste. PMID:19342214

Xará, Susana M; Delgado, Julanda N; Almeida, Manuel F; Costa, Carlos A

2009-04-01

413

Coronagraphic phase diversity: performance study and laboratory demonstration  

NASA Astrophysics Data System (ADS)

Context. The final performance of current and future instruments dedicated to exoplanet detection and characterization (such as SPHERE on the European Very Large Telescope, GPI on Gemini North, or future instruments on Extremely Large Telescopes) is limited by uncorrected quasi-static aberrations. These aberrations create long-lived speckles in the scientific image plane, which can easily be mistaken for planets. Aims: Common adaptive optics systems require dedicated components to perform wave-front analysis. The ultimate wave-front measurement performance is thus limited by the unavoidable differential aberrations between the wave-front sensor and the scientific camera. To reach the level of detectivity required by high-contrast imaging, these differential aberrations must be estimated and compensated for. In this paper, we characterize and experimentally validate a wave-front sensing method that relies on focal-plane data. Methods: Our method, called COFFEE (for COronagraphic Focal-plane wave-Front Estimation for Exoplanet detection), is based on a Bayesian approach, and it consists in an extension of phase diversity to high-contrast imaging. It estimates the differential aberrations using only two focal-plane coronagraphic images recorded from the scientific camera itself. Results: We first present a thorough characterization of COFFEE's performance by means of numerical simulations. This characterization is then compared with an experimental validation of COFFEE using an in-house adaptive optics bench and an apodized Roddier & Roddier phase mask coronagraph. An excellent match between experimental results and the theoretical study is found. Lastly, we present a preliminary validation of COFFEE's ability to compensate for the aberrations upstream of a coronagraph.

Paul, B.; Sauvage, J.-F.; Mugnier, L. M.

2013-04-01

414

a Laboratory Study of Single Sulfate Aerosols Using Electrodynamic Suspension  

NASA Astrophysics Data System (ADS)

Bithermal isopiestic measurements of the water vapor pressure of the (NH(,4))(,2)SO(,4)-NH(,4)HSO(,4) -H(,2)O system at room temperature have been made using single nanogram particles electrodynamically suspended in a modified quadrupole trap. Particle composition changed from NH(,4)HSO(,4) to (NH(,4))(,2)SO(,4) as NH(,3) gas was absorbed in situ. Particle relative mass during solid liquid phase transformations was measured with an electroslatic balance. Constant water activity curves for both dilute and supersaturated solutions are displayed on a (NH(,4))(,2)SO(,4) -NH(,4)HSO(,4)-H(,2)O phase diagram. From these measurements, a model is presented to explain the dynamics of dissolving mixed crystals. Applying electrolyte solution thermodynamics, values of the activity coefficient for aqueous solutions of (NH(,4))(,2)SO(,4) and NH(,4)HSO(,4) are calculated. The measured water activity of the various ammonium-hydrogen-sulfate solutions is compared to the predicted value of two models. The free energy of formation for the three crystalline structures of (NH(,4))(,2)SO(,4), (NH(,4))(,3)H(SO(,4))(,2) and NH(,4)HSO(,4) is approximated using the Gibbs-Duhem relation and our measured values of saturated solutions. Using nucleation theory and the measured composition and water activity of the solution upon crystallization, the specific nucleation barrier is deduced. Speculation about the size of the critical nucleus as a function of composition is made assuming that the total nucleation barrier is constant. A discussion of the study's application to atmospheric processes is included.

Spann, James Frederick, Jr.

415

Nitrogen limited biobarriers remove atrazine from contaminated water: laboratory studies.  

PubMed

Atrazine is one of the most frequently used herbicides. This usage coupled with its mobility and recalcitrant nature in deeper soils and aquifers makes it a frequently encountered groundwater contaminant. We formed biobarriers in sand filled columns by coating the sand with soybean oil; after which, we inoculated the barriers with a consortium of atrazine-degrading microorganisms and evaluated the ability of the barriers to remove atrazine from a simulated groundwater containing 1 mg L(-1) atrazine. The soybean oil provided a carbon rich and nitrogen poor substrate to the microbial consortium. Under these nitrogen-limiting conditions it was hypothesized that bacteria capable of using atrazine as a source of nitrogen would remove atrazine from the flowing water. Our hypothesis proved correct and the biobarriers were effective at removing atrazine when the nitrogen content of the influent water was low. Levels of atrazine in the biobarrier effluents declined with time and by the 24th week of the study no detectable atrazine was present (limit of detection<0.005 mg L(-1)). Larger amounts of atrazine were also removed by the biobarriers; when biobarriers were fed 16.3 mg L(-1) atrazine 97% was degraded. When nitrate (5 mg L(-1) N), an alternate source of nitrogen, was added to the influent water the atrazine removal efficiency of the barriers was reduced by almost 60%. This result supports the hypothesis that atrazine was degraded as a source of nitrogen. Poisoning of the biobarriers with mercury chloride resulted in an immediate and large increase in the amount of atrazine in the barrier effluents confirming that biological activity and not abiotic factors were responsible for most of the atrazine degradation. The presence of hydroxyatrazine in the barrier effluents indicated that dehalogenation was one of the pathways of atrazine degradation. Permeable barriers might be formed in-situ by the injection of innocuous vegetable oil emulsions into an aquifer or sandy soil and used to remove atrazine from a contaminated groundwater or to protect groundwater from an atrazine spill. PMID:18848368

Hunter, William J; Shaner, Dale L

2008-09-10

416

Behavioral Assessment of Intermittent Wheel Running and Individual Housing in Mice in the Laboratory  

Microsoft Academic Search

Physical cage enrichment—exercise devices for rodents in the laboratory—often in- cludes running wheels. This study compared responses of mice in enriched physical and social conditions and in standard social conditions to wheel running, individual housing, and open-field test. The study divided into 6 groups, 48 female BALB\\/c mice group housed in enriched and standard conditions. On alternate days, the study

Therese M. Pham; Stefan Brené; Vera Baumans

417

Differentiation in seed hoarding among three sympatric rodent species in a warm temperate forest.  

PubMed

Although seed hoarding by rodents has been extensively studied, differentiation in seed-hoarding behaviors among sympatric rodent species has not been well investigated. Using semi-natural enclosures, we demonstrated that three sympatric rodent species showed clear differentiation in food selection, scatter versus larder hoarding behaviors and eating behaviors when offered seeds of four plant species from a warm temperate forest in northern China. The large field mouse Apodemus peninsulae preferred seeds of wild apricot (Prunus armeniaca) and Liaodong oak (Quercus liaotungensis), whereas the Chinese white-bellied rat Niviventor confucianus preferred seeds of cultivated walnut and Liaodong oak, and the David's rock squirrel Sciurotamias davidianus preferred seeds of cultivated walnut, wild apricot and Liaodong oak. All three rodents showed larder hoarding of seeds from all four plant species, but the large field mouse showed scatter hoarding of wild apricot, and the David's rock squirrel showed scatter hoarding of Liaodong oak and wild walnut. Acorns of Liaodong oak, which have a soft seed hull, were more often eaten in situ, whereas wild walnuts, which have a hard seed hull and more tannin, were less hoarded by all rodent species. Differentiation in the scatter versus larder hoarding behaviors of sympatric rodent species suggests that sympatric rodents play different roles in the regeneration of different sympatric plant species. PMID:21396061

Lu, Jiqi; Zhang, Zhibin

2008-06-01

418

Typing of Brachyspira spp. from rodents, pigs and chickens on Swedish farms.  

PubMed

The aim of the current study was to look for evidence of possible cross-species transmission of Brachyspira species between rodents and farm animals. To do this, previously collected and characterised Brachyspira isolates from rodents, pigs and chickens on the same farms were analysed by random amplified polymorphic DNA (RAPD). Isolates with similar RAPD banding patterns were further typed by pulsed-field gel electrophoresis (PFGE). Identical isolates of Brachyspira pilosicoli, Brachyspira intermedia, Brachyspira murdochii and Brachyspira innocens from pigs and rodents and of B. murdochii from laying hens and rodents were found, indicating cross-species transmission at farm level. PFGE data from rodent isolates of Brachyspira hyodysenteriae were compared with PFGE data from previously typed field isolates of B. hyodysenteriae from pigs with swine dysentery and isolates from mallards (Anas platyrhynchos). Three of four isolates of B. hyodysenteriae from rodents were similar to porcine field isolates by PFGE. PCR analyses of the plasmid-encoded and potential virulence determinants rfb genes B, A, D and C showed that they were present in isolates of B. hyodysenteriae of porcine, mallard and rodent origin. PMID:21497461

Backhans, A; Jansson, D S; Aspán, A; Fellström, C

2011-03-26

419

Anti-dementia drugs and hippocampal-dependent memory in rodents  

PubMed Central

Abnormalities in hippocampal structure and function are characteristics of early Alzheimer's disease (AD). Behavioral tests measuring hippocampal-dependent memory in rodents are often used to evaluate novel treatments for AD and other dementias. In this study, we review the effects of drugs marketed for the treatment of AD, such as the acetylcholinesterase inhibitors, donepezil, rivastigmine, galantamine and the N-methyl-d-aspartic acid antagonist, memantine, in rodent models of memory impairment. We also briefly describe the effects of novel treatments for cognitive impairment in rodent models of memory impairment, and discuss issues concerning the selection of the animal model and behavioral tests. Suggestions for future research are offered.

Yuede, Carla M.; Dong, Hongxin; Csernansky, John G.

2009-01-01

420

Chemotherapy of Rodent Malaria (Annual Report, October 16, 1985-October 15, 1990).  

National Technical Information Service (NTIS)

In vivo studies in a rodent malaria model have confirmed that resistance to chloroquine is reversed by verapamil and also shown this effect with ketotifen and pizotyline. WR 238605 and desipramine had little activity. Penfluridol, cyproheptadine and ketot...

W. Peters

1990-01-01

421

A Comparison of a Biological Sciences Curriculum Study (BSCS) Laboratory and a Traditional Laboratory on Student Achievement at Two Private Liberal Arts Colleges.  

ERIC Educational Resources Information Center

|The purpose of this experiment was to compare an inquiry-oriented Biological Sciences Curriculum Study (BSCS) style laboratory approach with a more directive traditional approach on student outcomes in the cognitive and affective domains of learning at two private, midwestern liberal arts colleges. Intact laboratory sections of students enrolled…

Hall, Donald A.; McCurdy, Donald W.

422

Preliminary study: Formaldehyde exposure in laboratories of Sharjah university in UAE  

PubMed Central

Objectives Laboratory technicians, students, and instructors are at high risk, because they deal with chemicals including formaldehyde. Thus, this preliminary study was conducted to measure the concentration of formaldehyde in the laboratories of the University of Sharjah in UAE. Materials and Methods: Thirty-two air samples were collected and analyzed for formaldehyde using National Institute for Occupational Safety and Health (NIOSH) method 3500. In this method, formaldehyde reacts with chromotropic acid in the presence of sulfuric acid to form a colored solution. The absorbance of the colored solution is read in spectrophotometer at wavelength 580 nm and is proportional to the quantity of the formaldehyde in the solution. Results: For the anatomy laboratory and in the presence of the covered cadaver, the mean concentration of formaldehyde was found to be 0.100 ppm with a range of 0.095–0.105 ppm. Whereas for the other laboratories, the highest mean concentration of formaldehyde was 0.024 ppm in the general microbiology laboratory and the lowest mean concentration of formaldehyde was 0.001 ppm in the environmental health laboratory. The 8-hour (time-weighted average) concentration of formaldehyde was found to be ranging between 0.0003 ppm in environmental health laboratory and 0.026 ppm in the anatomy laboratory. Conclusions: The highest level of concentration of formaldehyde in the presence of the covered cadaver in anatomy laboratory exceeded the recommended ceiling standard established by USA-NIOSH which is 0.1 ppm, but below the ceiling standard established by American Conference of Governmental Industrial Hygienists which is 0.3 ppm. Thus, it is recommended that formaldehyde levels should be measured periodically specially during the dissection in the anatomy laboratory, and local exhaust ventilation system should be installed and personal protective equipment such as safety glass and gloves should be available and be used to prevent direct skin or eye contact.

Ahmed, Hafiz Omer

2011-01-01

423

Guinea-zilla? World's largest rodent  

NSDL National Science Digital Library

Roughly the size of a buffalo, a giant rodent that roamed the banks of an ancient Venezuelan river some 8 million years ago, dining on sea grass and dodging crocodiles, was an evolutionary sibling to modern-day guinea pigs.

American Association for the Advancement of Science (AAAS;)

2008-07-03

424

Past and Future Work on Radiobiology Mega Studies: A Case Study at Argonne National Laboratory  

PubMed Central

Between 1952 and 1992 more than 200 large radiobiology studies were conducted in research institutes throughout Europe, North America and Japan to determine the effects of external irradiation and internal emitters on the life span and tissue toxicity development in animals. At Argonne National Laboratory, 22 external beam studies were conducted on nearly 700 beagle dogs and 50,000 mice between 1969 and 1992. These studies helped to characterize the effects of neutron and gamma irradiation on lifespan, tumorigenesis, and mutagenesis across a range of doses and dosing patterns. The records and tissues collected at Argonne during that time period have been carefully preserved and redisseminated. Using these archived data ongoing statistical work has been done and continues to characterize quality of radiation, dose, dose rate, tissue, and gender specific differences in the radiation responses of exposed animals. The ongoing application of newly developed molecular biology techniques to the archived tissues has revealed gene specific mutation rates following exposure to ionizing irradiation. The original and ongoing work with this tissue archive is presented here as a case study of a more general trend in the radiobiology mega studies. These experiments helped form the modern understanding of radiation responses in animals, and continue to inform development of new radiation models. Recent archival efforts have facilitated open access to the data and materials produced by these studies and so a unique opportunity exists to expand this continued research.

Haley, Benjamin; Wang, Qiong; Wanzer, Beau; Vogt, Stefan; Finney, Lydia; Yang, Ping Liu; Paunesku, Tatjana; Woloschak, Gayle

2013-01-01

425

Site study plan for routine laboratory rock mechanics, Deaf Smith County Site, Texas: Revision 1  

SciTech Connect

This Site Study Plan for Routine Laboratory Rock Mechanics describes routine laboratory testing to be conducted on rock samples collected as part of the characterization of the Deaf Smith County site, Texas. This study plan describes the early laboratory testi