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1

Born to run. Studying the limits of human performance  

PubMed Central

It is recognised that regular physical activity and a high level of fitness are powerful predictors of positive health outcomes. There is a long and rich history of significant feats of human endurance with some, for example, the death of the first marathon runner, Pheidippides, associated with negative health outcomes. Early studies on endurance running used X-ray and interview techniques to evaluate competitors and comment on performance. Since then, comparatively few studies have looked at runners competing in distances longer than a marathon. Those that have, tend to show significant musculoskeletal injuries and a remarkable level of adaptation to this endurance load. The TransEurope Footrace Project followed ultra-endurance runners aiming to complete 4,500 Km of running in 64 days across Europe. This pioneering study will assess the impact of extreme endurance on human physiology; analysing musculoskeletal and other tissue/organ injuries, and the body's potential ability to adapt to extreme physiological stress. The results will be of interest not only to endurance runners, but to anyone interested in the limits of human performance. Please see related article: http://www.biomedcentral.com/1741-7015/10/78

2012-01-01

2

APS: Studying the Human Physiological Limits of Exploring Mars  

NSDL National Science Digital Library

This Web Seminar, developed in collaboration with the National Science Digital Library, took place on Wednesday, May 13, 2009 from 6:30 p.m. to 8:00 p.m. Eastern time. In this seminar, Dr Pawelczyk examined the effects of long-term travel on the human body in outer space.

PhD James A Pawelczyk (Pennsylvania State University)

2009-05-13

3

Limiter study  

SciTech Connect

Studies of energy deposition on a mushroom-shaped limiter have been performed on ZT-40M. Total energy deposition, estimated power deposition per unit area, the effects of gas puffing and vertical and error field application, and approximate time histories of the extent of the impact area are presented for two different current levels (120 and 190 kA), protrusions into the body of the plasma (+2 - +12 mm from the wall) and limiter materials. Photographs of a bare graphite and TiC-coated graphite limiter before and after exposure to the plasma are shown. Massive spallation of the TiC-coated limiter is observed at the higher current level. Spallation occurs during the discharge and after termination. The degree of spallation is dependent on the current level. The average power deposition on the limiter over the discharge is estimated to be less than or equal to 1 MW.

Downing, J.N.; Gordon, R.A.; Thomas, K.S.; Watt, R.G.

1983-08-01

4

Limits of resolution of genetic linkage studies: implications for the positional cloning of human disease genes.  

PubMed Central

Positional cloning studies to identify disease genes are being carried out for many human genetic diseases. Such studies often include a genome-scan linkage analysis to identify the rough chromosomal location of a disease gene, fine structure genetic mapping to define and narrow the chromosomal interval in which the disease gene may be located, and physical mapping and gene identification in the genetically defined interval to clone the disease gene. During the planning of a positional cloning study, it is important to know that, if linkage is found, the genetic interval identified is likely to be sufficiently narrow to be dissected efficiently by methods of physical mapping and gene identification. Thus, we wish to know the limits of resolution of a genetic linkage study. In this paper, I determine for Mendelian diseases the distributions and moments of three measures of linkage resolution: (1) in a set of N chromosomes, the distance between the nearest crossovers that flank a disease locus, (2) the distance between the nearest genetic markers that flank the pair of flanking crossovers after a genome scan, and (3) the distance between the nearest flanking markers after additional randomly placed markers are generated and typed in an identified interval. These results provide explicit sample-size guidelines for future positional cloning studies of Mendelian diseases and make possible a more objective evaluation of whether a proposed positional cloning study is likely to be successful. I also briefly discuss the more difficult problem of linkage resolution for complex genetic diseases.

Boehnke, M.

1994-01-01

5

Addressing the Limitations of Protocol Analysis in the Study of Complex Human Behavior  

Microsoft Academic Search

Many commentators have argued that the protocol analysis method (Ericsson & Simon, 1993) has considerable utility in the study of complex human behavior. In particular, it has recently been suggested that this method allows for detailed analyses of human language and cognition from a behavioral perspective. Despite this utility, however, relatively few behavioral studies have employed this technique. In the

Francisco Cabello; Denis OHora

2002-01-01

6

Limits of resolution of genetic linkage studies: Implications for the positional cloning of human disease genes  

SciTech Connect

Positional cloning studies to identify disease genes are being carried out for many human genetic diseases. Such studies often include a genome-scan linkage analysis to identify the rough chromosomal location of a disease gene, fine structure genetic mapping to define and narrow the chromosomal interval in which the disease gene may be located, and physical mapping and gene identification in the genetically defined interval to clone the disease gene. During the planning of a positional cloning study, it is important to know that, if linkage is found, the genetic interval identified is likely to be sufficiently narrow to be dissected efficiently by methods of physical mapping and gene identification. Thus, one wishes to know the limits of resolution of a genetic linkage study. In this paper, the author determines for Mendelian diseases the distributions and moments of three measures of linkage resolution: (1) in a set of N chromosomes, the distance between the nearest crossovers that flank a disease locus, (2) the distance between the nearest genetic markers that flank the pair of flanking crossovers after a genome scan, and (3) the distance between the nearest flanking markers after additional randomly placed markers are generated and typed in an identified interval. These results provide explicit sample-size guidelines for future positional cloning studies of Mendelian diseases and make possible a more objective evaluation of whether a proposed positional cloning study is likely to be successful. The author also briefly discusses the more difficult problem of linkage resolution for complex genetic diseases. 14 refs., 1 fig., 6 tabs.

Boehnke, M. (Univ. of Michigan, Ann Arbor, MI (United States))

1994-08-01

7

Archive: APS: Studying the Human Physiological Limits of Exploring Mars, May 13, 2009  

NSDL National Science Digital Library

Dr. Jim Pawelczyk, Associate Professor of Physiology, Kinesiology and Medicine at Pennsylvania State University has had extensive experience as an astronaut and researcher on the effects of microgravity on the human body. Missions to Mars would require humans to travel well beyond the current record of 15 months by a Russian astronaut, and doubling that length to nearly 30 months. Factors such as the environment, bone repair and growth, radiation, psychological stamina, and other influences play a critical role towards achieving this goal. Data from previous missions such as the International Space Station and Skylab have helped in determining how to address these challenges, but Pawelczyk points out the need to inspire today's students to realize the solutions and possibilities of such travel since they will be our astronauts, engineers, and scientists of tomorrow. For more information about this web seminar, its presenter(s), read what participants said about it, and to see and download its PowerPoint slides go here .

1900-01-01

8

Limits of predictability in human mobility  

NASA Astrophysics Data System (ADS)

A range of applications, from predicting the spread of human and electronic viruses to city planning and resource management in mobile communications, depend on our ability to foresee the whereabouts and mobility of individuals, raising a fundamental question: to what degree is human behaviour predictable? Here we explore the limits of predictability in human dynamics by studying the mobility patterns of anonymized mobile phone users. By measuring the entropy of each individual's trajectory, we find a 93% potential predictability in user mobility across the whole user base. Despite the significant differences in the travel patterns, we find a remarkable lack of variability in predictability, being largely independent of the distance user cover on a regular basis. We show that the origin of this deep- rooted predictability is the quantifiable regularity of human activity and discuss the potential implications of our findings.

Song, Chaoming; Qu, Zehui; Blumm, Nicholas; Barabasi, Albert-Laszlo

2010-03-01

9

Limits of predictability in human mobility.  

PubMed

A range of applications, from predicting the spread of human and electronic viruses to city planning and resource management in mobile communications, depend on our ability to foresee the whereabouts and mobility of individuals, raising a fundamental question: To what degree is human behavior predictable? Here we explore the limits of predictability in human dynamics by studying the mobility patterns of anonymized mobile phone users. By measuring the entropy of each individual's trajectory, we find a 93% potential predictability in user mobility across the whole user base. Despite the significant differences in the travel patterns, we find a remarkable lack of variability in predictability, which is largely independent of the distance users cover on a regular basis. PMID:20167789

Song, Chaoming; Qu, Zehui; Blumm, Nicholas; Barabási, Albert-László

2010-02-19

10

Wildlife Need Habitat Off Limits to Humans  

Microsoft Academic Search

In 4 million years of human evolution, there has never been an area off limits to humans—an area that we deliberately choose not to enter so that species that live there can flourish unmolested by humans. Yet, our observations and intuition about wildlife suggest that most want and need such seclusion in order to survive. Recent research confirms this. Even

Michael J. Vandeman

11

Human Rights Watch: Limits of Tolerance  

NSDL National Science Digital Library

Human Rights Watch has recently posted a new report. "Limits of Tolerance: Freedom of Expression and the Public Debate in Chile," examines the extreme restrictions on freedom of speech and freedom of information in the ostensibly democratic nation of Chile.

12

Limitations of Hairless Mouse Skin as a Model for In Vitro Permeation Studies Through Human Skin: Hydration Damage  

Microsoft Academic Search

Hairless mouse skin currently provides a popular model membrane for studies in human percutaneous absorption. Although some similarities between the two skin types have been demonstrated, the effects of prolonged hydration on hairless mouse skin have not previously been rigorously examined. We have measured in vitro the effects of hydration at 31°C on the permeabilities of hairless mouse skin and

John Russell Bond; Brian William Barry

1988-01-01

13

Competition, Human Capital and Income Inequality with Limited Commitment  

Microsoft Academic Search

We develop a dynamic general equilibrium model with two-sided limited commitment to study how barriers to competition, such as restrictions to business start-up, affect the incentive to accumulate human capital. We show that a lack of contract enforceability amplifies the effect of barriers to competition on human capital accumulation. High barriers reduce the incentive to accumulate human capital by lowering

Ramon Marimon; Vincenzo Quadrini

2008-01-01

14

Limits to sustainable human metabolic rate.  

PubMed

There is a limit to the performance of an organism set by energy intake and energy mobilization. Here, the focus is on humans with unlimited access to food and for whom physical activity can be limited by energy mobilization. The physical activity level (PAL) in the general population, calculated as doubly-labelled-water-assessed average daily metabolic rate as a multiple of basal metabolic rate, has an upper limit of 2.2-2.5. The upper limit of sustainable metabolic rate is approximately twice as high in endurance athletes, mainly because of long-term exercise training with simultaneous consumption of carbohydrate-rich food during exercise. Endurance athletes have an increased fat-free mass and can maintain energy balance at a PAL value of 4.0-5.0. High altitude limits exercise performance as a result of combined effects on nutrient supply and the capacity to process nutrients. Thus, trained subjects climbing Mount Everest reached PAL values of 2.0-2.7, well below the observed upper limit at sea level. PMID:11581332

Westerterp, K R

2001-09-01

15

Face processing limitation to own species in primates: A comparative study in brown capuchins, Tonkean macaques and humans  

Microsoft Academic Search

Most primates live in social groups which survival and stability depend on individuals’ abilities to create strong social relationships with other group members. The existence of those groups requires to identify individuals and to assign to each of them a social status. Individual recognition can be achieved through vocalizations but also through faces. In humans, an efficient system for the

Valerie Dufour; Olivier Pascalis; Odile Petit

2006-01-01

16

Competition, human capital and income inequality with limited commitment  

Microsoft Academic Search

We develop a dynamic model with two-sided limited commitment to study how barriers to competition, such as restrictions to business start-up and non-competitive covenants, affect the incentive to accumulate human capital. When contracts are not enforceable, high barriers lower the outside value of ‘skilled workers’ and reduce the incentive to accumulate human capital. In contrast, low barriers can result in

Ramon Marimon; Vincenzo Quadrini

2011-01-01

17

Limits to human locomotor performance: phylogenetic origins and comparative perspectives  

Microsoft Academic Search

Studies of human exercise physiology have been conducted from a largely ahistorical perspective. This approach usefully elucidates proximate limits to locomotor performance, but ignores potential sources of biomechanical and physiological variation that derive from adaptation to ancestral environments. Phylogenetic reconstruction suggests that multiple hominoid lineages, including that leading to Homo sapiens, evolved in African highlands at altitudes of 1000-2000 m.

Robert Dudley

2001-01-01

18

Characterizing the Limits of Human Visual Awareness  

Microsoft Academic Search

Momentary awareness of a visual scene is very limited; however, this limitation has not been formally characterized. We test the hypothesis that awareness reflects a surprisingly impoverished data structure called a labeled Boolean map, defined as a linkage of just one feature value per dimension (for example, the color is green and the motion is rightward) with a spatial pattern.

Liqiang Huang; Anne Treisman; Harold Pashler

2007-01-01

19

Parvocellular neurons limit motion acuity in human peripheral vision.  

PubMed

It is generally believed that the perception of moving targets is mediated by the magnocellular (M) pathway in primate vision, but evidence is emerging that the parvocellular (P) pathway may also play a role in motion perception. Human peripheral vision is susceptible to anomalous motion perception because of spatial aliasing, and in this study we used this fact to determine if the P pathway can mediate information about low- and high-velocity stimuli. Psychometric functions relating visual performance to stimulus spatial frequency were measured for the directional discrimination of drifting sinusoidal gratings presented at 40 degrees eccentricity. Applying the sampling theorem to our results, we estimated that the Nyquist frequency of the limiting sampling array for directional discrimination is 1.7 cycles per degree. This result was compared with the Nyquist limit and spatial filtering properties of M and P ganglion cells in the human peripheral retina, calculated from histological data on their density and dendritic field size. Our results provide evidence to suggest that the reversed motion illusion in human peripheral vision is due to spatial aliasing by the P ganglion cell mosaic. We conclude that the sampling density of P ganglion cells limits veridical motion acuity in human peripheral vision, even for high-velocity targets. This provides further evidence that the P pathway is involved in processing information about motion. PMID:7644544

Anderson, S J; Drasdo, N; Thompson, C M

1995-07-22

20

Leroi-Gourhan and the Limits of the Human  

Microsoft Academic Search

Leroi-Gourhan’s investigation of human prehistory in Le Geste et la parole questions the boundaries, or limits, that more traditional kinds of humanism have assigned to the human, pushing back the origins of the human to include hominid forms that might previously have been regarded as ‘prehuman’, and widening our definition of the human by considering the diverse ‘externalizations’ of mind

Christopher Johnson

2011-01-01

21

Leroi-Gourhan and the Limits of the Human  

Microsoft Academic Search

: Leroi-Gourhan’s investigation of human prehistory in Le Geste et la parole questions the boundaries, or limits, that more traditional kinds of humanism have assigned to the human, pushing back the origins of the human to include hominid forms that might previously have been regarded as ‘prehuman’, and widening our definition of the human by considering the diverse ‘externalizations’ of

Christopher Johnson

2011-01-01

22

Characterizing the limits of human visual awareness.  

PubMed

Momentary awareness of a visual scene is very limited; however, this limitation has not been formally characterized. We test the hypothesis that awareness reflects a surprisingly impoverished data structure called a labeled Boolean map, defined as a linkage of just one feature value per dimension (for example, the color is green and the motion is rightward) with a spatial pattern. Features compete with each other, whereas multiple locations form a spatial pattern and thus do not compete. Perception of the colors of two objects was significantly improved by successive compared with simultaneous presentation, whereas perception of their locations was not. Moreover, advance information about which objects are relevant aided perception of colors much more than perception of locations. Both results support the Boolean map hypothesis. PMID:17690299

Huang, Liqiang; Treisman, Anne; Pashler, Harold

2007-08-10

23

Approaching the limit of predictability in human mobility.  

PubMed

In this study we analyze the travel patterns of 500,000 individuals in Cote d'Ivoire using mobile phone call data records. By measuring the uncertainties of movements using entropy, considering both the frequencies and temporal correlations of individual trajectories, we find that the theoretical maximum predictability is as high as 88%. To verify whether such a theoretical limit can be approached, we implement a series of Markov chain (MC) based models to predict the actual locations visited by each user. Results show that MC models can produce a prediction accuracy of 87% for stationary trajectories and 95% for non-stationary trajectories. Our findings indicate that human mobility is highly dependent on historical behaviors, and that the maximum predictability is not only a fundamental theoretical limit for potential predictive power, but also an approachable target for actual prediction accuracy. PMID:24113276

Lu, Xin; Wetter, Erik; Bharti, Nita; Tatem, Andrew J; Bengtsson, Linus

2013-10-11

24

Approaching the Limit of Predictability in Human Mobility  

NASA Astrophysics Data System (ADS)

In this study we analyze the travel patterns of 500,000 individuals in Cote d'Ivoire using mobile phone call data records. By measuring the uncertainties of movements using entropy, considering both the frequencies and temporal correlations of individual trajectories, we find that the theoretical maximum predictability is as high as 88%. To verify whether such a theoretical limit can be approached, we implement a series of Markov chain (MC) based models to predict the actual locations visited by each user. Results show that MC models can produce a prediction accuracy of 87% for stationary trajectories and 95% for non-stationary trajectories. Our findings indicate that human mobility is highly dependent on historical behaviors, and that the maximum predictability is not only a fundamental theoretical limit for potential predictive power, but also an approachable target for actual prediction accuracy.

Lu, Xin; Wetter, Erik; Bharti, Nita; Tatem, Andrew J.; Bengtsson, Linus

2013-10-01

25

Approaching the Limit of Predictability in Human Mobility  

PubMed Central

In this study we analyze the travel patterns of 500,000 individuals in Cote d'Ivoire using mobile phone call data records. By measuring the uncertainties of movements using entropy, considering both the frequencies and temporal correlations of individual trajectories, we find that the theoretical maximum predictability is as high as 88%. To verify whether such a theoretical limit can be approached, we implement a series of Markov chain (MC) based models to predict the actual locations visited by each user. Results show that MC models can produce a prediction accuracy of 87% for stationary trajectories and 95% for non-stationary trajectories. Our findings indicate that human mobility is highly dependent on historical behaviors, and that the maximum predictability is not only a fundamental theoretical limit for potential predictive power, but also an approachable target for actual prediction accuracy.

Lu, Xin; Wetter, Erik; Bharti, Nita; Tatem, Andrew J.; Bengtsson, Linus

2013-01-01

26

Limitations on the cloning of humans and other mammals  

Microsoft Academic Search

The nature of clones is discussed along with the origin and principles of the concept that human and other mammalian clones can be produced. The physical and chemical properties of living cells are described and it is shown these properties place severe limitations on attempts to bring human and mammalian clones into being. The observed result of such attempts that

D. S Robertson

2004-01-01

27

Limited replication of influenza A virus in human mast cells.  

PubMed

Mast cells are important in innate immunity and protective against certain bacterial infections. However, there is limited evidence that mast cells respond to viruses. As mast cells are abundant in mucosal tissues of the lung, they are in a prime location to detect and respond to influenza virus. In this study, we characterized for the first time the replication cycle of influenza A virus in human mast cells by measuring influenza A virus transcription, RNA replication, protein synthesis, and formation of infectious virus as compared to the replication cycle in epithelial cells. We detected the presence of influenza A viral genomic RNA transcription, replication, and protein synthesis in human mast cells and epithelial cells. However, there was no significant release of infectious influenza A virus from mast cells, whereas epithelial cells produce ~100-fold virus compared with the inoculating dose. We confirmed that influenza A virus infects human mast cells, begins to replicate, but the production of new virus is aborted. Thus, mast cells may lack critical factors essential for productive infection or there are intrinsic or inducible anti-influenza A mechanisms in mast cells. PMID:23055084

Marcet, Candy W; St Laurent, Chris D; Moon, Tae Chul; Singh, Nav; Befus, A Dean

2013-05-01

28

Can Computers Help Overcome Limitations in Human Decision Making?  

Microsoft Academic Search

The article considers the development of computer-assisted decision support in the context of contemporary research on the forms of thinking used by decision makers. It outlines the potential that computers have for overcoming known limitations in human thinking related to processing capacity and memory and the problems that occur when these applications are developed without full knowledge of the different

A. John Maule

2010-01-01

29

VISUAL IMPLICIT LEARNING OVERCOMES LIMITS IN HUMAN ATTENTION  

Microsoft Academic Search

The human cognitive system is stunningly powerful in some respects yet surprisingly limited in others. We can recognize an object or a face in a single glimpse and type 70 words per minute, yet we cannot hold more than a few objects at a time in working memory or split our attention to several locations. Attention and working memory impose

Y. V. Jiang; L.-W. King; W. M. Shim; T. J. Vickery

30

Pumped-limiter study for Alcator DCT  

SciTech Connect

A study was performed for a pumped-limiter design for the proposed Alcator DCT device. The study focused on reactor-relevant issues. The main issues examined were configuration, surface erosion, thermal hydraulics, and the choice of structural and surface materials. A bottom, flat limiter, with a copper-alloy substrate, seems to be a reasonable design and should provide an opportunity to test high power and particle loadings. Carbon is recommended as a surface material if acceptable redeposition properties can be demonstrated.

Brooks, J.N.; Mattas, R.F.; Cha, Y.S.; Hassanein, A.M.; Majumdar, S.

1983-06-01

31

A Limitation Study into Access Decoupling  

Microsoft Academic Search

This paper presents a study into the theoretical limits of a latency hiding technique called access decoupling. Access decoupling is effective at hiding memory latency for low ILP and conservative dependency analysis [9,12,13]. We assess if this result still applies for maximum ILP and perfect dependency analysis.

G. P. Jones; Nigel P. Topham

1997-01-01

32

Closed Ecological Systems (CES) Functional Stability Limits and Human Control  

NASA Astrophysics Data System (ADS)

newline Global planet The Earth Closed System stability of functioning is based on principle of statistical regulations and provided by enormous planetary buffer capacities atmosphere water soil time and sources of energy natural and fossilized All current deviations caused by human activity in Earth Biosphere are being easily eliminated and absorbed by these planetary buffers Man-made Closed Ecosystems function at the limits of their natural stability due to insufficient buffer capacities we have to minimize system size and physical mass to get it into the space principle of statistical regulations becomes insufficient for stability maintenance and needs to be replaced by other control approaches It had been indicated qualitatively earlier Gitelson et al 1975 that Human Factor HF purposeful control can increase these systems stability levels if applies algorithms compatible to man-made CES natural functioning mechanisms Theoretical analysis is being done on the basis of the results obtained in different experiments for closed ecosystems of different scale Biosphere of the Earth Biosphere -- 2 BIOS -- 3 etc It is shown that certain limits of functional stability exist for each specific system in terms of average cycle rate and fluctuations range These limits are determined primarily by newline - system s natural buffer capacities newline - rate of slowest material cycle in the system - natural structure of the chemical elements cycles - HF human consumption conversion material load on to the cycles

Rygalov, V.; Nelson, M.; de Silva, S.

33

Effects of band-limited noise on human observer performance  

NASA Astrophysics Data System (ADS)

Perception tests establish the effects of spatially band-limited noise and blur on human observer performance. Previously, Bijl showed that the contrast threshold of a target image with spatially band-limited noise is a function of noise spatial frequency. He used the method of adjustment to find the contrast thresholds for each noise frequency band. A noise band exists in which the target contrast threshold reaches a peak relative to the threshold for higher- or lower-noise frequencies. Bijl also showed that the peak of this noise band shifts as high frequency information is removed from the target images. To further establish these results, we performed forced-choice experiments. First, a Night Vision and Electronics Sensors Directorate (NVESD) twelve (12)-target infrared tracked vehicle image set identification (ID) experiment, second, a bar-pattern resolving experiment, and third, a Triangle Orientation Discrimination (TOD) experiment. In all of the experiments, the test images were first spatially blurred, then spatially band-limited noise was added. The noise center spatial frequency was varied in half-octave increments over seven octaves. Observers were shown images of varying target-to-noise contrasts, and a contrast threshold was calculated for each spatial noise band. Finally, we compared the Targeting Task Performance (TTP) human observer model predictions for performance in the presence of spatially band-limited noise with these experimental results.

Salem, Salem; Jacobs, Eddie; Moore, Richard; Hogervorst, Maarten; Bijl, Piet; Halford, Carl

2007-05-01

34

Limited Inhibitory Effects of Oseltamivir and Zanamivir on Human Sialidases?  

PubMed Central

Oseltamivir (Tamiflu) and zanamivir (Relenza), two extensively used clinically effective anti-influenza drugs, are viral sialidase (also known as neuraminidase) inhibitors that prevent the release of progeny virions and thereby limit the spread of infection. Recently mortalities and neuropsychiatric events have been reported with the use of oseltamivir, especially in pediatric cases in Japan, suggesting that these drugs might also inhibit endogenous enzymes involved in sialic acid metabolism, including sialidase, sialyltransferase, and CMP-synthase, in addition to their inhibitory effects on the viral sialidase. The possible inhibition could account for some of the rare side effects of oseltamivir. However, there has been little direct evidence in regard to the sensitivities of animal sialidases to these drugs. Here, we examined whether these inhibitors might indeed affect the activities of human sialidases, which differ in primary structures and enzyme properties but possess tertiary structures similar to those of the viral enzymes. Using recombinant enzymes corresponding to the four human sialidases identified so far, we found that oseltamivir carboxylate scarcely affected the activities of any of the sialidases, even at 1 mM, while zanamivir significantly inhibited the human sialidases NEU3 and NEU2 in the micromolar range (Ki, 3.7 ± 0.48 and 12.9 ± 0.07 ?M, respectively), providing a contrast to the low nanomolar concentrations at which these drugs block the activity of the viral sialidases.

Hata, Keiko; Koseki, Koichi; Yamaguchi, Kazunori; Moriya, Setsuko; Suzuki, Yasuo; Yingsakmongkon, Sangchai; Hirai, Go; Sodeoka, Mikiko; von Itzstein, Mark; Miyagi, Taeko

2008-01-01

35

Receivers Limit the Prevalence of Deception in Humans: Evidence from Diving Behaviour in Soccer Players  

PubMed Central

Deception remains a hotly debated topic in evolutionary and behavioural research. Our understanding of what impedes or facilitates the use and detection of deceptive signals in humans is still largely limited to studies of verbal deception under laboratory conditions. Recent theoretical models of non-human behaviour have suggested that the potential outcome for deceivers and the ability of receivers to discriminate signals can effectively maintain their honesty. In this paper, we empirically test these predictions in a real-world case of human deception, simulation in soccer. In support of theoretical predictions in signalling theory, we show that cost-free deceit by soccer players decreases as the potential outcome for the signaller becomes more costly. We further show that the ability of receivers (referees) to detect deceptive signals may limit the prevalence of deception by soccer players. Our study provides empirical support to recent theoretical models in signalling theory, and identifies conditions that may facilitate human deception and hinder its detection.

David, Gwendolyn K.; Condon, Catriona H.; Bywater, Candice L.; Ortiz-Barrientos, Daniel; Wilson, Robbie S.

2011-01-01

36

Limited communication capacity unveils strategies for human interaction  

NASA Astrophysics Data System (ADS)

Connectivity is the key process that characterizes the structural and functional properties of social networks. However, the bursty activity of dyadic interactions may hinder the discrimination of inactive ties from large interevent times in active ones. We develop a principled method to detect tie de-activation and apply it to a large longitudinal, cross-sectional communication dataset (~19 months, ~20 million people). Contrary to the perception of ever-growing connectivity, we observe that individuals exhibit a finite communication capacity, which limits the number of ties they can maintain active in time. On average men display higher capacity than women, and this capacity decreases for both genders over their lifespan. Separating communication capacity from activity reveals a diverse range of tie activation strategies, from stable to exploratory. This allows us to draw novel relationships between individual strategies for human interaction and the evolution of social networks at global scale.

Miritello, Giovanna; Lara, Rubén; Cebrian, Manuel; Moro, Esteban

2013-06-01

37

Limited communication capacity unveils strategies for human interaction.  

PubMed

Connectivity is the key process that characterizes the structural and functional properties of social networks. However, the bursty activity of dyadic interactions may hinder the discrimination of inactive ties from large interevent times in active ones. We develop a principled method to detect tie de-activation and apply it to a large longitudinal, cross-sectional communication dataset (?19 months, ?20 million people). Contrary to the perception of ever-growing connectivity, we observe that individuals exhibit a finite communication capacity, which limits the number of ties they can maintain active in time. On average men display higher capacity than women, and this capacity decreases for both genders over their lifespan. Separating communication capacity from activity reveals a diverse range of tie activation strategies, from stable to exploratory. This allows us to draw novel relationships between individual strategies for human interaction and the evolution of social networks at global scale. PMID:23739519

Miritello, Giovanna; Lara, Rubén; Cebrian, Manuel; Moro, Esteban

2013-01-01

38

Overexcitation limiter modeling for power system studies  

Microsoft Academic Search

IEEE standard 421.5 on excitation systems models is in the process of being updated. Many additional control functions are being added and the existing ones have experienced significant modifications. This paper outlines the model for over excitation limiters.

Shawn Patterson

2005-01-01

39

Limiting Factors for the Generation of Hypothiocyanite Ion, an Antimicrobial Agent, in Human Saliva  

Microsoft Academic Search

The limiting factors for the generation of the bacterial inhibitor, hypothiocyanite OSCN- ion, in human whole saliva were studied. Significant increase in OSCN- production could be achieved both in vitro and in vivo by supplementing saliva with peroxide alone or with a combination of peroxide and SCN-. The most effective initial H2O2 concentration was 700 ?M. Higher concentrations caused a

K. M. Pruitt; J. Tenovuo; W. Fleming; M. Adamson

1982-01-01

40

Limits  

NSDL National Science Digital Library

Students will see how the idea of a limit can be presented both in formal epsilon-delta-style terms, and using corresponding animations. After calculating a limit for a simple example function, we point out that limits do not always exist.

Liao, David

41

Toward a theology of limits. Seen in the right way, limits can enlarge the range of human possibility.  

PubMed

Many in healthcare bemoan the limits-on, for example, budgets, patient autonomy, and life-prolonging interventions--of the 1990s. But limits can enhance, as well as constrict, human possibilities. Genesis reminds us that being limited is part of being human. Without limits, we would not need to become responsible. We would not need compassion, reconciliation, healing, prudence, risk, or trust. Hopes and dreams would be irrelevant. We would be paralyzed by indifference. The Bible also tells us that God is self-limiting. The New Testament describes God's self-limiting Incarnation as Jesus of Nazareth. The theology of Incarnation says that God works not in spite of human structures, experiences, and limits, but through them. The doctrine of the Trinity shows that God's own identity consists in relationship. It is from the perspective of community that one sees modern humanity's greatest ethical challenges. If we of the Catholic ministry are to be at the healthcare table, we must be willing to compromise. And we must be at the table if our values of inherent human dignity, social justice, and care for society's outcasts are to have a voice. PMID:10623175

Smith, P

42

Tolerance limit of human head-neck region to high speed windblast.  

PubMed

To provide parameters for designers of open type escape system in an aircraft, aerodynamic and biomechanical characteristics of human head-neck region was studied and analysed. The results show that tolerance limit of human head-neck region are 2.452 kN, 1.358 kN and 0.169 kN to aerodynamic drag, aerodynamic lift, and aerodynamic side force respectively during high speed windblast. Meanwhile the curve of tolerance limit to high speed windblast is given. Regardless of crewman posture during ejection, human head-neck region is free from windblast injury unless the aerodynamic force exerted on the head-neck region is within the above-mentioned value. PMID:11539894

Zhang, Y; Wu, G

1997-02-01

43

Physiology for High School - Human Physiological Limits to Exploring Mars  

NSDL National Science Digital Library

The keynote presentation from EB 2008's Physiology for Life Science High School Teachers and Students Workshop. This powerpoint presentation discusses the possibility of human exploration on Mars, specifically, how space flight and life on mars would effect human physiology.

PhD James A Pawelczyk (Pennsylvania State University)

2008-04-05

44

Limited Capital Market Participation and Human Capital Risk  

Microsoft Academic Search

The non-tradability of human capital is often cited for the failure of traditional asset pricing theory to explain agents' portfolio holdings. In this paper we argue that the opposite might be true --- traditional models might not be able to explain agent portfolio holdings because they do not explicitly account for the fact that human capital does trade (in the

Jonathan Berk; Johan Walden

2010-01-01

45

Limited interaction between translation and visual motion aftereffects in humans.  

PubMed

After exposure to a moving sensory stimulus, subsequent perception is often biased in the opposite direction. This phenomenon, known as an aftereffect, has been extensively studied for optic flow stimuli where it is known as the visual motion aftereffect (MAE). Such visual motion can also generate the sensation of self-motion or vection. It has recently been demonstrated that fore-aft translation in darkness also produces an aftereffect. The current study examines the interaction between visual MAE and vestibular translation aftereffects. Human subjects participated in a two-interval experiment in which the first interval (adapter) was visual, translation, or both combined congruently or in conflict. Subjects identified the direction of the second (test) interval of either visual or translation using a forced-choice technique. The translation adapter had no influence on visual test stimulus perception, and the visual adapter did not influence vestibular test stimulus perception in any subjects. However, congruent visual and translation induced a significantly larger perceptual bias on the translation test stimulus than was observed for a translation only adapter. The congruent adapter caused the MAE to be diminished relative to a visual only adapter. Conflicting visual and vestibular adapters produced an aftereffect similar to that seen when the single adapting stimulus was the same modality as the test stimulus. These results suggest that unlike visual and translation stimuli whose combined influence on perception can be predicted based on the effects of each stimulus individually, the effects of combined visual and translation stimuli on aftereffects cannot be predicted from the influences of each stimulus individually. PMID:23064848

Crane, Benjamin T

2012-10-14

46

Limited human infection due to recombinant raccoon pox virus  

USGS Publications Warehouse

A laboratory accident resulted in human exposure to a recombinant raccoon poxvirus (RCN) developed as a vaccine vector for antigens of Yersinia pestis for protection of wild rodents (and other animals) against plague. Within 9 days, the patient developed a small blister that healed within 4 weeks. Raccoon poxvirus was cultured from the lesion, and the patient developed antibody to plague antigen (F1) and RCN. This is the first documented case of human exposure to RCN.

Rocke, T. E.; Dein, F. J.; Fuchsberger, M.; Fox, B. C.; Stinchcomb, D. T.; Osorio, J. G.

2004-01-01

47

In vivo-in vitro tumour cell lines: characteristics and limitations as models for human cancer.  

PubMed Central

In vivo-in vitro tumour cell lines are widely used to study the biology of cancer and to examine the factors influencing the response of tumours to therapeutic agents and regimens. The existing in vivo-in vitro tumours form a uniform and artificial population of experimental neoplasms, with biological characteristics which limit the acceptability of any of these tumours or panel of these tumours as an accurate model for human cancer. All are rapidly growing, transplanted tumours in highly inbred rodents. All have growth rates, cell proliferation patterns and tumour-host interactions different from those of primary tumours in animals or man. Most are immunogenic. Most are anaplastic sarcomas: few are carcinomas; none are well differentiated. The biological differences between in vivo-in vitro tumours and human neoplasms must be considered when the experimental systems are used as models for human cancer.

Rockwell, S.

1980-01-01

48

Problems and Limitations in Studies on Screening for Language Delay  

ERIC Educational Resources Information Center

|This study discusses six common methodological limitations in screening for language delay (LD) as illustrated in 11 recent studies. The limitations are (1) whether the studies define a target population, (2) whether the recruitment procedure is unbiased, (3) attrition, (4) verification bias, (5) small sample size and (6) inconsistencies in…

Eriksson, Marten; Westerlund, Monica; Miniscalco, Carmela

2010-01-01

49

Closed Ecological Systems (CES) Functional Stability Limits and Human Control  

Microsoft Academic Search

newline Global planet The Earth Closed System stability of functioning is based on principle of statistical regulations and provided by enormous planetary buffer capacities atmosphere water soil time and sources of energy natural and fossilized All current deviations caused by human activity in Earth Biosphere are being easily eliminated and absorbed by these planetary buffers Man-made Closed Ecosystems function at

V. Rygalov; M. Nelson; S. de Silva

2006-01-01

50

Concurrent excitors limit the extinction of conditioned fear in humans  

Microsoft Academic Search

In a human fear conditioning experiment, with on-line expectancy ratings and electrodermal responding as indices of fear, two neutral stimuli (pictures of geometric shapes) were first established as reliable predictors of an electric shock. In the subsequent extinction phase, the two stimuli were repeatedly presented in compound, without the shock. The final test phase consisted of individual stimulus presentations again,

Bram Vervliet; Debora Vansteenwegen; Dirk Hermans; Paul Eelen

2007-01-01

51

47 CFR 5.93 - Limited market studies.  

Code of Federal Regulations, 2012 CFR

...or receiving equipment used in the study shall be owned by the licensee...the Commission shall establish on a case-by-case basis. If the Commission subsequently determines that a market study is not so limited, the study...

2012-10-01

52

Limited Life Expectancy, Human Capital and Health Investments: Evidence from Huntington Disease  

Microsoft Academic Search

One of the most basic predictions of human capital theory is that life expectancy should impact human capital investment. Limited exogenous variation in life expectancy makes this difficult to test, especially in the contexts most relevant to the macroeconomic applications. We estimate the relationship between life expectancy and human capital investments using genetic variation in life expectancy driven by Huntington

Emily Oster; Ira Shoulson; E. Ray Dorsey

2012-01-01

53

Pulmonary system limitations to endurance exercise performance in humans.  

PubMed

Accumulating evidence over the past 25 years depicts the healthy pulmonary system as a limiting factor of whole-body endurance exercise performance. This brief overview emphasizes three respiratory system-related mechanisms which impair O(2) transport to the locomotor musculature [arterial O(2) content (C(aO(2))) × leg blood flow (Q(L))], i.e. the key determinant of an individual's aerobic capacity and ability to resist fatigue. First, the respiratory system often fails to prevent arterial desaturation substantially below resting values and thus compromises C(aO(2)). Especially susceptible to this threat to convective O(2) transport are well-trained endurance athletes characterized by high metabolic and ventilatory demands and, probably due to anatomical and morphological gender differences, active women. Second, fatiguing respiratory muscle work (W(resp)) associated with strenuous exercise elicits sympathetically mediated vasoconstriction in limb-muscle vasculature, which compromises Q(L). This impact on limb O(2) transport is independent of fitness level and affects all individuals, but only during sustained, high-intensity endurance exercise performed above ?85% maximal oxygen uptake. Third, excessive fluctuations in intrathoracic pressures accompanying W(resp) can limit cardiac output and therefore Q(L). Exposure to altitude exacerbates the respiratory system limitations observed at sea level, further reducing C(aO(2)) and substantially increasing exercise-induced W(resp). Taken together, the intact pulmonary system of healthy endurance athletes impairs locomotor muscle O(2) transport during strenuous exercise by failing to ensure optimal arterial oxygenation and compromising Q(L). This respiratory system-related impact exacerbates the exercise-induced development of fatigue and compromises endurance performance. PMID:22125308

Amann, Markus

2011-11-28

54

The fanconi anemia pathway limits human papillomavirus replication.  

PubMed

High-risk human papillomaviruses (HPVs) deregulate epidermal differentiation and cause anogenital and head and neck squamous cell carcinomas (SCCs). The E7 gene is considered the predominant viral oncogene and drives proliferation and genome instability. While the implementation of routine screens has greatly reduced the incidence of cervical cancers which are almost exclusively HPV positive, the proportion of HPV-positive head and neck SCCs is on the rise. High levels of HPV oncogene expression and genome load are linked to disease progression, but genetic risk factors that regulate oncogene abundance and/or genome amplification remain poorly understood. Fanconi anemia (FA) is a genome instability syndrome characterized at least in part by extreme susceptibility to SCCs. FA results from mutations in one of 15 genes in the FA pathway, whose protein products assemble in the nucleus and play important roles in DNA damage repair. We report here that loss of FA pathway components FANCA and FANCD2 stimulates E7 protein accumulation in human keratinocytes and causes increased epithelial proliferation and basal cell layer expansion in the HPV-positive epidermis. Additionally, FANCD2 loss stimulates HPV genome amplification in differentiating cells, demonstrating that the intact FA pathway functions to restrict the HPV life cycle. These findings raise the possibility that FA genes suppress HPV infection and disease and suggest possible mechanism(s) for reported associations of HPV with an FA cohort in Brazil and for allelic variation of FA genes with HPV persistence in the general population. PMID:22623785

Hoskins, Elizabeth E; Morreale, Richard J; Werner, Stephen P; Higginbotham, Jennifer M; Laimins, Laimonis A; Lambert, Paul F; Brown, Darron R; Gillison, Maura L; Nuovo, Gerard J; Witte, David P; Kim, Mi-Ok; Davies, Stella M; Mehta, Parinda A; Butsch Kovacic, Melinda; Wikenheiser-Brokamp, Kathryn A; Wells, Susanne I

2012-05-23

55

Primary structure of the human laminin A chain. Limited expression in human tissues.  

PubMed Central

cDNA clones for the human laminin A chain were isolated from libraries prepared from human gestational choriocarcinoma cell line (JAR) RNA. They cover approx. 8 kb from the 5'-end of the 9.5 kb mRNA coding for this protein. Our clones contain 94 nucleotide residues for the 5'-end untranslated region and 7885 nucleotide residues of coding sequence. The complete human laminin A chain contains a 17-amino acid-residue signal peptide and a 3058-residue A chain proper. The human laminin A chain has a distinct domain structure with numerous internal cysteine-rich repeats. The large globular domain G has five repeats, which have several conserved glycine and cysteine residues. Furthermore the A chain contains 20 internal cysteine-rich repeats present in tandem arrays in three separate clusters (domains IIIa, IIIb and V). Domain I + II has a predicted continuous alpha-helical structure characterized by heptad repeats and three domains (IVa, IVb and VI) are predicted to contain a number of beta-sheets and coiled-coil structures. Northern-blot analysis was used to study the laminin A chain expression in the JAR cell line, full-term placenta and newborn-human tissues (kidney, spleen, lung, heart muscle, psoas muscle and diaphragm muscle). The expression was detectable in newborn-human kidney and JAR cell line only. The overall amino acid sequence identity between human and mouse is 76%. The human chain has only one Arg-Gly-Asp (RGD) sequence, which is located in the long arm within domain G, whereas the single RGD sequence in the mouse chain is located in the short arm in domain IIIb. The degree of identity between the human laminin A chain sequence and the sequence available for merosin [Ehrig, Leivo, Argraves, Ruoslahti & Engvall (1990) Proc. Natl. Acad. Sci. U.S.A. 87, 3264-3268] is about 41% and when conservative substitutions are included the degree of similarity is 54%. Images Fig. 3.

Nissinen, M; Vuolteenaho, R; Boot-Handford, R; Kallunki, P; Tryggvason, K

1991-01-01

56

A theoretical study on forming limit diagrams prediction  

Microsoft Academic Search

The paper develops a theoretical study on forming limit diagrams using a new general code for forming limit strains prediction. Treating the Marciniak and Kuckzinsky (M–K) theory by a new approach, the code consists of the main part and several subroutines, which allow the implementation of any hardening law, yield function or constitutive equation, changing the respective subroutine. The strong

M. C. Butuc; J. J. Gracio; A. Barata da Rocha

2003-01-01

57

Human Exploration Mission Studies.  

National Technical Information Service (NTIS)

The nation's efforts to expand human presence and activity beyond Earth orbit into the solar system was given renewed emphasis in January of 1988 when the Presidential Directive on National Space Policy was signed into effect. The expansion of human prese...

R. L. Cataldo

1989-01-01

58

Quantitative analysis of human internal limiting membrane extracted from patients with macular holes.  

PubMed

We report the study of the morphology, topography, and adhesion properties of internal limiting membrane (ILM) from patients with macular holes. The quantitative analysis of human ILM could provide essential information toward the improvement of existing surgical instruments for more efficient and safer surgical removal of ILM. Imaging in air revealed the presence of globular structures in most of the samples analyzed which were coupled with fibrillar structures in some of the samples. Modification of silicon nitride AFM tips with oppositely charged functional groups showed changes in adhesion force at the membrane-tip interface. Defining the surface characteristics of the human ILM is an initial step in the development of improved surgical tools that may allow nontraumatic stripping of ILM during surgery. PMID:20597525

Valentín-Rodríguez, Celimar; Tezel, Tongalp H; Ivanisevic, Albena

2010-08-01

59

Environmental Risk Limits for alcohols, glycols, and other relatively soluble and\\/or volatile compounds. 2. Integration of human and ecotoxicological risk limits  

Microsoft Academic Search

Environmental risk limits are concentrations of a substance in water,\\u000aair, sediment and soil that are expected to be protective of the\\u000aenvironment. In this report environmental risk limits (ERLs) are\\u000aderived, based on a comparison of human and ecotoxicological risk limits. \\u000aEcotoxicological risk limits, derived previously, were compared to risk\\u000alimits for human health for the following substances: 1-butanol,

Traas TP; Bontje D

2007-01-01

60

Internationalisation of Bharat Forge Limited: a case study  

Microsoft Academic Search

Purpose – The purpose of this paper is to follow the internationalisation of an Indian company, Bharat Forge Limited. It studies how a small company from India becomes one of the leading players in the global forging industry. Design\\/methodology\\/approach – This is a case study approach for studying the process of internationalisation in one particular firm. Findings – Bharat Forge

Rajesh K. Pillania

2008-01-01

61

Physical Performance Limitations in the Childhood Cancer Survivor Study Cohort  

PubMed Central

Physical performance limitations are one of the potential long-term consequences following diagnosis and treatment for childhood cancer. The purpose of this review is to describe the risk factors for and the participation restrictions that result from physical performance limitations among childhood cancer survivors who participated in the Childhood Cancer Survivor Study (CCSS). Articles previously published from the CCSS cohort related to physical performance limitations were reviewed and the results summarized. Our review showed that physical performance limitations are prevalent among childhood cancer survivors and may increase as they age. Host-based risk factors for physical disability include an original diagnosis of bone tumor, brain tumor, or Hodgkin's disease; female sex; and an income less than $20,000 per year. Treatment-based risk factors include radiation and treatment with a combination of alkylating agents and anthracyclines. Musculoskeletal, neurologic, cardiac, pulmonary, sensory, and endocrine organ system dysfunction also increase the risk of developing a physical performance limitation. In summary, monitoring of physical performance limitations in an aging cohort of childhood cancer survivors is important and will help determine the impact of physical performance limitations on morbidity, mortality, and caregiver burden. In addition, in developing restorative and preventive interventions for childhood cancer survivors, we must take into account the special needs of survivors with physical disability to optimize their health and enhance participation in daily living activities.

Ness, Kirsten K.; Hudson, Melissa M.; Ginsberg, Jill P.; Nagarajan, Rajaram; Kaste, Sue C.; Marina, Neyssa; Whitton, John; Robison, Leslie L.; Gurney, James G.

2009-01-01

62

Perspectives: Why Study Human Genetics?  

ERIC Educational Resources Information Center

Reasons for studying human genetics are discussed. These include philosophical reasons, reasons of health, and social reasons. While content, interpretation, and emphasis of human genetics study will vary depending upon schools, teachers, and developmental stages of students, it is suggested that teachers address these three domains. (Author/JN)

Childs, Barton

1983-01-01

63

On Editing and Human Studies  

Microsoft Academic Search

It is both an honor and a pleasure to participate in celebrating 25 years of Human Studies by serving as guest editor of this Special Issue. In assembling this volume I have been able to experience ab initio the many facets of Human Studies that make it such an important journal – its interdisciplinary character, high intellectual standards, commitment to

Frances Chaput Waksler

2002-01-01

64

Parasites of importance for human health in Nigerian dogs: high prevalence and limited knowledge of pet owners  

Microsoft Academic Search

BACKGROUND: Dogs are the most common pet animals worldwide. They may harbour a wide range of parasites with zoonotic potential, thus causing a health risk to humans. In Nigeria, epidemiological knowledge on these parasites is limited. METHODS: In a community-based study, we examined 396 dogs in urban and rural areas of Ilorin (Kwara State, Central Nigeria) for ectoparasites and intestinal

Uade Samuel Ugbomoiko; Liana Ariza; Jorg Heukelbach

2008-01-01

65

Problems and limitations in studies on screening for language delay.  

PubMed

This study discusses six common methodological limitations in screening for language delay (LD) as illustrated in 11 recent studies. The limitations are (1) whether the studies define a target population, (2) whether the recruitment procedure is unbiased, (3) attrition, (4) verification bias, (5) small sample size and (6) inconsistencies in choice of "gold standard". It is suggested that failures to specify a target population, high attrition (both at screening and in succeeding validation), small sample sizes and verification bias in validations are often caused by a misguided focus on screen positives (SPs). Other limitations are results of conflicting methodological goals. We identified three such conflicts. One consists of a dilemma between unbiased recruitment and attrition, another between the comprehensiveness of the applied gold standard and sample size in validation and the third between the specificity of the gold standard and the risk of not identifying co-morbid conditions. PMID:20483561

Eriksson, Mårten; Westerlund, Monica; Miniscalco, Carmela

2010-05-18

66

Limited Transfer of Newly Acquired Movement Patterns across Walking and Running in Humans  

PubMed Central

The two major modes of locomotion in humans, walking and running, may be regarded as a function of different speed (walking as slower and running as faster). Recent results using motor learning tasks in humans, as well as more direct evidence from animal models, advocate for independence in the neural control mechanisms underlying different locomotion tasks. In the current study, we investigated the possible independence of the neural mechanisms underlying human walking and running. Subjects were tested on a split-belt treadmill and adapted to walking or running on an asymmetrically driven treadmill surface. Despite the acquisition of asymmetrical movement patterns in the respective modes, the emergence of asymmetrical movement patterns in the subsequent trials was evident only within the same modes (walking after learning to walk and running after learning to run) and only partial in the opposite modes (walking after learning to run and running after learning to walk) (thus transferred only limitedly across the modes). Further, the storage of the acquired movement pattern in each mode was maintained independently of the opposite mode. Combined, these results provide indirect evidence for independence in the neural control mechanisms underlying the two locomotive modes.

Ogawa, Tetsuya; Kawashima, Noritaka; Ogata, Toru; Nakazawa, Kimitaka

2012-01-01

67

Non-human primate models of childhood psychopathology: the promise and the limitations.  

PubMed

Although non-human primate models have been used previously to investigate the neurobiology of several sensory and cognitive developmental pathologies, they have been employed only sparingly to study the etiology of childhood psychopathologies for which deficits in social behavior and emotion regulation are major symptoms. Previous investigations of both adult human and non-human primates have indicated that primate social behavior and emotion are regulated by a complex neural network, in which the amygdala and orbital frontal cortex play major roles. Therefore, this review will provide information generated from the study of macaque monkeys regarding the timing of normal social and emotional behavior development, the normal pattern of anatomical and functional maturation of the amygdala and orbital frontal cortex, as well as information regarding the neural and behavioral effects of early perturbations of these two neural structures. We will also highlight 'critical periods' of macaque development, during which major refinements in the behavioral repertoire appear to coincide with significant neural maturation of the amygdala and/or orbital frontal cortex. The identification of these 'critical periods' may allow one to better predict the specific behavioral impairments likely to appear after neonatal damage to one or both of these neural areas at different time points during development. This experimental approach may provide a new and important way to inform and stimulate research on childhood psychopathologies, such as autism, schizophrenia and Williams syndrome, in which the development of normal social skills and emotional regulation is severely perturbed. Finally, the promise and limitations inherent to the use of non-human primate models of childhood psychopathology will be discussed. PMID:12553413

Machado, Christopher J; Bachevalier, Jocelyne

2003-01-01

68

Olfactory study: human pheromones.  

PubMed

Recent work suggests that short-chain aliphatic acids in vaginal secretions may play a role of pheromones in primates, including humans. An experiment was conducted with 3 women to determmine the odor composition of vaginal secretions before and after coitus. Prior to coitus they refrained from sexual activities for 48 hours, did not use a vaginal douche for 7 days, did not bathe or shower for 24 hours, and did not use vaginal hygiene preparations for 72 hours. Samples of vaginal secretions were taken at 9:00 A.M., 1:00 P.M., and 5:00 P.M. on the day before coitus. After coitus at 7:00 A.M., samples were again taken from each subject at the same hours as before. A condom was used in 1 coitus to prevent male secretions and seminal fluids from entering vaginal secretions. The GC/sensory assay (odorogram) was used and odor description notes made. The survey indicated that 13 odorous compounds occurred regularly. It was noted that components with acidic odor tended to appear at lower retention rates in postcoital samples. The chemistry of these compounds was not investigated. It is concluded that differences exist in the odors of pre- and postcoital vaginal secretions. The biological relevance of these differences was unresolved. The question of the pheromonic significance of vaginal odors in humans remains undetermined. PMID:1174306

Keith, L; Draunieks, A; Krotoszynski, B K

1975-07-29

69

On the design of experiments to study extreme field limits  

NASA Astrophysics Data System (ADS)

We propose experiments on the collision of high intensity electromagnetic pulses with electron bunches and on the collision of multiple electromagnetic pulses for studying extreme field limits in the nonlinear interaction of electromagnetic waves. The effects of nonlinear QED will be revealed in these laser plasma experiments.

Bulanov, S. S.; Chen, M.; Schroeder, C. B.; Esarey, E.; Leemans, W. P.; Bulanov, S. V.; Esirkepov, T. Zh.; Kando, M.; Koga, J. K.; Zhidkov, A. G.; Chen, P.; Mur, V. D.; Narozhny, N. B.; Popov, V. S.; Thomas, A. G. R.; Korn, G.

2012-12-01

70

On the design of experiments to study extreme field limits  

SciTech Connect

We propose experiments on the collision of high intensity electromagnetic pulses with electron bunches and on the collision of multiple electromagnetic pulses for studying extreme field limits in the nonlinear interaction of electromagnetic waves. The effects of nonlinear QED will be revealed in these laser plasma experiments.

Bulanov, S. S.; Chen, M.; Schroeder, C. B.; Esarey, E.; Leemans, W. P.; Bulanov, S. V.; Esirkepov, T. Zh.; Kando, M.; Koga, J. K.; Zhidkov, A. G.; Chen, P.; Mur, V. D.; Narozhny, N. B.; Popov, V. S.; Thomas, A. G. R.; Korn, G. [University of California, Berkeley, California 94720 (United States); Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States) and University of California, Berkeley, California 94720 (United States); Kansai Photon Science Institute, JAEA, Kizugawa, Kyoto 619-0215 (Japan); Osaka University, Osaka 565-0871 (Japan); Leung Center for Cosmology and Particle Astrophysics, National Taiwan University, Taipei 10617, Taiwan (China); Moscow Engineering Physics Institute (State University), Moscow 115409 (Russian Federation); Institute of Theoretical and Experimental Physics, Moscow 117218 (Russian Federation); University of Michigan, Ann Arbor, Michigan 48103 (United States); Max-Planck-Institut fur Quantenoptik, Garching 85748 (Germany) and ELI Beamline Facility, Institute of Physics, Czech Academy of Sciences, Prague 18221 (Czech Republic)

2012-12-21

71

Nurses’ compliance with alarm limits for pulse oximetry: qualitative study  

Microsoft Academic Search

Objective:Monthly audits for the multicenter Canadian Oxygen Trial have shown that our neonatal team has consistently maintained study participants within the intended pulse oximetry alarm limits between 68 and 79% of the time during the first 3 days of life while infants were receiving supplemental oxygen. This good performance prompted us to explore our nurses’ perceptions of what makes them

J Armbruster; B Schmidt; C F Poets; D Bassler

2010-01-01

72

Studies in Interactive Communication: Limited Vocabulary Natural Language Dialogue.  

National Technical Information Service (NTIS)

The complexity and costs of interactive, natural-language computer systems could be reduced if the man-computer communication used only a limited subset of the English language. The purpose of this study was to test the hypothesis that people, although ac...

M. J. Kelly

1975-01-01

73

Determining the influence of population variation on compliance with radiofrequency exposure limits: proposed study.  

PubMed

Currently, compliance with safety limits for human exposure to radiofrequency (RF) fields is demonstrated by methods that rely on certain assumptions and approximations, which include among other things, human anatomical features, tissue types and the dielectric properties of these tissues. This paper reviews some of the available data and outlines a proposal for an encompassing study to investigate which of these assumptions are appropriate; what approximation can be used in physical and computational modeling of humans for specific energy absorption rate (SAR) calculations (a key compliance metric); and what trade-offs can be made between accuracy and modeling requirements for practical considerations. Key issues to be investigated are how SAR varies between children and adults, between males and females, and how to model SAR in the fetus of pregnant females. It is hoped that the proposed study will produce models and methods which allow for faster, more accurate and more efficient compliance with radiofrequency exposure limits. PMID:17282864

Sauren, Maia; McKenzie, Ray; Cosic, Irena

2005-01-01

74

Human limits for hypoxia. The physiological challenge of climbing Mt. Everest.  

PubMed

Climbing Mt. Everest without supplementary oxygen presents a fascinating physiological challenge because, at the summit, humans are very near the limit of tolerance to hypoxia. It was not until 1978 that the feat was accomplished, and this was after many unsuccessful attempts over a period of more than 50 years, and several physiological studies that suggested that it would be impossible. An analysis shows that the critical factors for reaching the summit are the enormous hyperventilation which is necessary to maintain the alveolar PO2 at viable levels, the fact that the barometric pressure is substantially higher than predicted by the Standard Atmosphere, and the severe respiratory alkalosis that assists loading of oxygen by the blood in the lung. Even so the maximal oxygen consumption on the summit is extremely low with the result that climbers are critically vulnerable to unexpected setbacks such as changes in the weather. PMID:10863526

West, J B

2000-01-01

75

Population and prehistory II: Space-limited human populations in constant environments  

PubMed Central

We present a population model to examine the forces that determined the quality and quantity of human life in early agricultural societies where cultivable area is limited. The model is driven by the non-linear and interdependent relationships between the age distribution of a population, its behavior and technology, and the nature of its environment. The common currency in the model is the production of food, on which age-specific rates of birth and death depend. There is a single nontrivial equilibrium population at which productivity balances caloric needs. One of the most powerful controls on equilibrium hunger level is fertility control. Gains against hunger are accompanied by decreases in population size. Increasing worker productivity does increase equilibrium population size but does not improve welfare at equilibrium. As a case study we apply the model to the population of a Polynesian valley before European contact.

Puleston, Cedric O.; Tuljapurkar, Shripad

2010-01-01

76

Determination of torque-limits for human and cat lumbar spine specimens during displacement-controlled physiological motions  

PubMed Central

Background Context Quadruped animal models have been validated and utilized as biomechanical models for the lumbar spine. The biomechanics of the cat lumbar spine has not been well characterized, even though it is a common model used in neuromechanical studies. Purpose Compare the physiological ranges of motion and determine torque-limits for cat and human lumbar spine specimens during physiological motions. Study Design/Setting Biomechanics study. Patient Sample Cat and human lumbar spine specimens. Outcome measures Intervertebral angle (IVA), joint moment, yield point, torque-limit, correlation coefficients. Methods Cat (L2-sacrum) and human (T12-sacrum) lumbar spine specimens were mechanically tested to failure during displacement-controlled extension, lateral bending, and axial rotation. Single trials consisted of 10 cycles (10mm/s or 5°/s) to a target displacement where the magnitude of the target displacement was increased for subsequent trials until failure occurred. Whole-lumbar stiffness, torque at yield point, and joint stiffness were determined. Scaling relationships were established using equations analogous to those that describe the load response of elliptically-shaped beams. Results IVA magnitudes for cat and human lumbar spines were similar during physiological motions. Human whole-lumbar and joint stiffness magnitudes were significantly greater than those for cat spine specimens (p<0.05). Torque-limits were also greater for humans compared to cats. Scaling relationships with high correlation (R2>0.77) were established during later lateral bending and axial rotation. Conclusions The current study defined “physiological ranges of movement” for human and cat lumbar spine specimens during displacement-controlled testing, and should be observed in future biomechanical studies conducted under displacement control.

Ianuzzi, Allyson; Pickar, Joel G.; Khalsa, Partap S.

2009-01-01

77

Challenge studies of human volunteers: ethical issues  

PubMed Central

There is a long history of medical research that involves intentionally infecting healthy people in order to study diseases and their treatments. Such research—what might be called "human challenge studies"—are an important strand of much current research—for example, in the development of vaccinations. The many international and national guidelines about the proper conduct of medical research do not specifically address human challenge studies. In this paper we review the guidelines on the risk of harm that healthy volunteers may be exposed to in the course of medical research. We examine the ethical arguments that are implicit or explicit in these guidelines. We then ask whether there is reason for limiting such studies on grounds independent of risk of harm. We conclude that the major ethical concern with challenge studies is that of risk of harm and that the fact that a study is a challenge study is not a wrong in itself.

Hope, T; McMillan, J

2004-01-01

78

A limited assessment of the ASEP human reliability analysis procedure using simulator examination results  

SciTech Connect

This report presents a limited assessment of the conservatism of the Accident Sequence Evaluation Program (ASEP) human reliability analysis (HRA) procedure described in NUREG/CR-4772. In particular, the, ASEP post-accident, post-diagnosis, nominal HRA procedure is assessed within the context of an individual`s performance of critical tasks on the simulator portion of requalification examinations administered to nuclear power plant operators. An assessment of the degree to which operator perforn:Lance during simulator examinations is an accurate reflection of operator performance during actual accident conditions was outside the scope of work for this project; therefore, no direct inference can be made from this report about such performance. The data for this study are derived from simulator examination reports from the NRC requalification examination cycle. A total of 4071 critical tasks were identified, of which 45 had been failed. The ASEP procedure was used to estimate human error probability (HEP) values for critical tasks, and the HEP results were compared with the failure rates observed in the examinations. The ASEP procedure was applied by PNL operator license examiners who supplemented the limited information in the examination reports with expert judgment based upon their extensive simulator examination experience. ASEP analyses were performed for a sample of 162 critical tasks selected randomly from the 4071, and the results were used to characterize the entire population. ASEP analyses were also performed for all of the 45 failed critical tasks. Two tests were performed to assess the bias of the ASEP HEPs compared with the data from the requalification examinations. The first compared the average of the ASEP HEP values with the fraction of the population actually failed and it found a statistically significant factor of two bias on the average.

Gore, B.R.; Dukelow, J.S. Jr.; Mitts, T.M.; Nicholson, W.L. [Pacific Northwest Lab., Richland, WA (United States)

1995-10-01

79

Preliminary study on limiting nutrients in seawater ponds  

NASA Astrophysics Data System (ADS)

A method for monitoring biological production of oxygen was used in the July 10-September 15, 1995 study on the limiting nutrients in eight land-based 5 m×5 m enclosures equipped with water stirrers in a seawater pond in the study region (Yellow Sea). Chicken manure only, chicken manure combined with chemical fertilizers, and chemical fertilizers only, were put into the enclosures, respectively. The results showed that phosphorus was the limiting nutrient; and that the optimal N:P ratio of the fertilizers was 7.25-7.54 (mean of 7.37), which was significantly lower than the ratio measured in the water, as phosphorus deposited is easily absorbed by sediments and is excessively uptaken by phytoplankton. The above optimal N:P ratio is suitable for daily fertilization with combination fertilizer in the seawater ponds.

Yang, Hong-Sheng; Li, De-Shang; Xu, Ning

1998-09-01

80

Study of dimethyl ether for limited streamer tubes  

NASA Astrophysics Data System (ADS)

Position resolution and lifetime have been studied for one-atmosphere DME in half-inch diameter aluminum tube chambers operated in the limited streamer mode. The radial resolution was measured by timing to be ?r = 73 ?m. The longitudinal resolution was measured by charge division to be <0.3% of the wire length. No significant gain changes were seen after 12 C/cm.

Wang, Y.-X.; Godfrey, G.

1992-08-01

81

Limitations of Surface EMG Signals of Extrinsic Muscles in Predicting Postures of Human Hand  

Microsoft Academic Search

This paper explores the limitations of sEMG (surface Electromyography) signals collected from the extrinsic muscles in the forearm in predicting the postures of human hand. Four subjects were asked to try ten extreme postures of hand which need high effort. Two of these four subjects were asked to try ten more normal postures which did not need effort During the

Ramana Vinjamuri; Zhi-Hong Mao; Robert Sclabassi; Mingui Sun

2006-01-01

82

STUDIES ON HUMAN ANTIBODIES  

PubMed Central

The composition of various isolated antibodies was determined by quantitative analyses for heavy chain subgroups and light chain types. Certain antibodies such as anti-tetanus toxoid and anti-A isoagglutinins were predominantly of the major ?G1-type. However, a high preponderance of molecules of the minor ?G2-subgroup was found for antibodies to dextran, levan, and teichoic acid. These findings explain some unusual features previously noted for anti-dextrans such as weak PCA reactions and lack of Gm antigens. Studies of several isolated antibodies from single heterozygous individuals showed a selective absence of genetic markers in certain antibodies and their presence in others. The "allelic exclusion" principle was clearly evident in the isolated antibodies of two different individuals. Large differences in the ratio of kappa to lambda light chains were observed for the same type of antibody from different individuals. Subfractionation of dextran antibodies by affinity for specific glycosidic linkage or combining site size produced marked changes in the ratios. The isomaltohexaose eluates of the dextran antibodies from two subjects were primarily kappa and the isomaltotriose eluates were predominantly lambda. The one anti-levan antibody studied was uniquely homogeneous, consisting exclusively of ?G2-heavy chains and kappa light chains. By these criteria as well as others, it closely resembled myeloma proteins.

Yount, William J.; Dorner, Marianne M.; Kunkel, Henry G.; Kabat, Elvin A.

1968-01-01

83

Study on inductive high-Tc superconducting fault current limiters  

Microsoft Academic Search

An inductive superconducting fault current limiter based on Bi-2212 tubes has been built. In this paper, we present the experimental results of static impedance tests and dynamic short circuit tests. The dynamic short circuit tests show the limiter can limit the fault current to a few times the nominal current. We evaluate the performance of the limiter and compare the

X. H. Zong; J. X. Wang; J. Sun; Y. N. Wang

2003-01-01

84

Study on inductive high- T c superconducting fault current limiters  

Microsoft Academic Search

An inductive superconducting fault current limiter based on Bi-2212 tubes has been built. In this paper, we present the experimental results of static impedance tests and dynamic short circuit tests. The dynamic short circuit tests show the limiter can limit the fault current to a few times the nominal current. We evaluate the performance of the limiter and compare the

X. H. Zong; J. X. Wang; J. Sun; Y. N. Wang

2003-01-01

85

Epigenetic studies in human diseases.  

PubMed

Irreversible genetic alterations underlying human diseases have been widely studied to date. However, it is evident that the potentially reversible epigenetic dysregulations may also have an important role in the disease origin. The studies of epigenetic mechanisms underlying disease onset, progression and pathogenesis have been performed in various human disorders. The epigenetic approaches may reveal useful markers for disease diagnostics, classification and prognostics as well as for progressive pharmacological treatment. This review summarizes the studies of epigenetic dysregulations including aberrant methylation, histone modifications and miRNA alterations in cancer as well as the studies of methylation changes and aberrant histone modifications in neurodegenerative, autoimmune, cardiovascular and other diseases. The imprinting disorders together with the emerging role of epigenetics in nutritional genomics, environment-organism interaction studies and in some other fields are also mentioned. PMID:20653993

Halusková, J

2010-01-01

86

Endotoxin tolerance does not limit mild ischemia-reperfusion injury in humans in vivo.  

PubMed

Animal studies have shown that previous exposure to lipopolysaccharide (LPS) can limit ischemia-reperfusion injury. We tested whether pretreatment with LPS also protects against ischemia-reperfusion injury in humans in vivo. Fourteen volunteers received bolus injections of incremental dosages of LPS on 5 consecutive days (LPS group). Before the first and 1 day after the last LPS administration, the forearm circulation of the non-dominant arm was occluded for 10 min, with concomitant intermittent handgripping to induce transient ischemia. After reperfusion, 0.1 mg of ( 99m)Tc-labeled annexin A5 (400 MBq) was injected intravenously to detect phosphatidylserine expression as an early marker of ischemia-reperfusion injury. Similarly, the control group (n = 10) underwent the ischemic exercise twice, but without pretreatment with LPS. Annexin A5 targeting was expressed as the percentage difference in radioactivity in the thenar muscle between both hands. Endotoxin tolerance developed during 5 consecutive days of LPS administration. Annexin A5 targeting was 12.1 +/- 2.2% and 10.4 +/- 2.1% before LPS treatment at 1 h and 4 h after reperfusion, compared to 12.2 +/- 2.4% and 8.9 +/- 2.1% at 1 h and 4 h after reperfusion on day 5 (P = 1.0 and 0.6, respectively). Also, no significant changes in annexin A5 targeting were found in the control group. So, in this model, LPS-tolerance does not protect against ischemia-reperfusion injury in humans in vivo. PMID:19710089

Draisma, Annelies; de Goeij, Moniek; Wouters, Constantijn W; Riksen, Niels P; Oyen, Wim J G; Rongen, Gerard A; Boerman, Otto C; van Deuren, M; van der Hoeven, Johannes G; Pickkers, Peter

2009-12-01

87

Fundamental limits of optical critical dimension metrology: a simulation study  

NASA Astrophysics Data System (ADS)

This paper is a comprehensive summary and analysis of a SEMATECH funded project to study the limits of optical critical dimension scatterometry (OCD). The project was focused on two primary elements: 1) the comparison, stability, and validity of industry models and 2) a comprehensive analysis of process stacks to evaluate the ultimate sensitivity and limits of OCD. Modeling methods are a requirement for the interpretation and quantitative analysis of scatterometry data. The four models evaluated show good agreement over a range of targets and geometries for zero order specular reflection as well as higher order diffraction. A number of process stacks and geometries representing semiconductor manufacturing nodes from the 45 nm node to the 18 nm node were simulated using several measurement modalities including angle-resolved scatterometry and spectrally-resolved scatterometry, measuring various combinations of intensity and polarization. It is apparent in the results that large differences are observed between those methods that rely upon unpolarized and single polarization measurements. Using the three parameter fits and assuming that the sensitivity of scatterometry must meet the criterion that the 3? uncertainty in the bottom dimension must be less than 2% of the linewidth, specular scatterometry solutions exist for all but the isolated lines at 18 nm node. Scatterometry does not have sufficient sensitivity for isolated and semi-isolated lines at the 18 nm node unless the measurement uses wavelengths as short as 200 nm or 150 nm and scans over large angle ranges.

Silver, Richard; Germer, Thomas; Attota, Ravikiran; Barnes, Bryan M.; Bunday, Benjamin; Allgair, John; Marx, Egon; Jun, Jay

2007-03-01

88

Identification of Multiple Rate-limiting Steps during the Human Mitochondrial Transcription Cycle in Vitro*  

PubMed Central

We have reconstituted human mitochondrial transcription in vitro on DNA oligonucleotide templates representing the light strand and heavy strand-1 promoters using protein components (RNA polymerase and transcription factors A and B2) isolated from Escherichia coli. We show that 1 eq of each transcription factor and polymerase relative to the promoter is required to assemble a functional initiation complex. The light strand promoter is at least 2-fold more efficient than the heavy strand-1 promoter, but this difference cannot be explained solely by the differences in the interaction of the transcription machinery with the different promoters. In both cases, the rate-limiting step for production of the first phosphodiester bond is open complex formation. Open complex formation requires both transcription factors; however, steps immediately thereafter only require transcription factor B2. The concentration of nucleotide required for production of the first dinucleotide product is substantially higher than that required for subsequent cycles of nucleotide addition. In vitro, promoter-specific differences in post-initiation control of transcription exist, as well as a second rate-limiting step that controls conversion of the transcription initiation complex into a transcription elongation complex. Rate-limiting steps of the biochemical pathways are often those that are targeted for regulation. Like the more complex multisubunit transcription systems, multiple steps may exist for control of transcription in human mitochondria. The tools and mechanistic framework presented here will facilitate not only the discovery of mechanisms regulating human mitochondrial transcription but also interrogation of the structure, function, and mechanism of the complexes that are regulated during human mitochondrial transcription.

Lodeiro, Maria F.; Uchida, Akira U.; Arnold, Jamie J.; Reynolds, Shelley L.; Moustafa, Ibrahim M.; Cameron, Craig E.

2010-01-01

89

Discussing study limitations in reports of biomedical studies- the need for more transparency  

PubMed Central

Unbiased and frank discussion of study limitations by authors represents a crucial part of the scientific discourse and progress. In today's culture of publishing many authors or scientific teams probably balance 'utter honesty' when discussing limitations of their research with the risk of being unable to publish their work. Currently, too few papers in the medical literature frankly discuss how limitations could have affected the study findings and interpretations. The goals of this commentary are to review how limitations are currently acknowledged in the medical literature, to discuss the implications of limitations in biomedical studies, and to make suggestions as to how to openly discuss limitations for scientists submitting their papers to journals. This commentary was developed through discussion and logical arguments by the authors who are doing research in the area of hedging (use of language to express uncertainty) and who have extensive experience as authors and editors of biomedical papers. We strongly encourage authors to report on all potentially important limitations that may have affected the quality and interpretation of the evidence being presented. This will not only benefit science but also offers incentives for authors: If not all important limitations are acknowledged readers and reviewers of scientific articles may perceive that the authors were unaware of them. Authors should take advantage of their content knowledge and familiarity with the study to prevent misinterpretations of the limitations by reviewers and readers. Articles discussing limitations help shape the future research agenda and are likely to be cited because they have informed the design and conduct of future studies. Instead of perceiving acknowledgment of limitations negatively, authors, reviewers and editors should recognize the potential of a frank and unbiased discussion of study limitations that should not jeopardize acceptance of manuscripts.

2012-01-01

90

Limitations of quantitative research in the study of structural adjustment.  

PubMed

Sociologists and, more recently, critical medical anthropologists have been arguing for a refocusing of the analysis of health and health care towards a perspective which considers the broader global political economy. In the context of the debt crisis and IMF/World Bank-inspired structural adjustment policies, the political economy theoretical perspective is becoming even more relevant in the analysis of health underdevelopment in many 'Third World' countries. This study focuses on the direct and indirect effects of the Jamaican debt crisis and structural adjustment programmes on health care services and health standards. In this paper it is argued that there are methodological problems using quantitative data when studying the effects of structural adjustment. In addition to providing a limited account of the effects, it is argued that the basic problem is a matter of the availability and reliability of the quantitative data in many 'Third World' countries. It is argued that some of these problems could be overcome by the application of qualitative micro-level analysis. This type of methodology is important to ascertain the effects of global processes at the grass roots level and to gain insights into what those working in the health sector are experiencing and what they perceive as the effects, if any, of structural adjustment policies. This has often been missing from the impersonal accounts offered by quantitative research on the subject to date. PMID:8658227

Lundy, P

1996-02-01

91

Study of capabilities and limitations of 3D printing technology  

NASA Astrophysics Data System (ADS)

3D printing is one of the developments in rapid prototyping technology. The inception and development of the technology has highly assisted the product development phase of product design and manufacturing. The technology is particularly important in educating product design and 3D modeling because it helps students to visualize their design idea, to enhance their creative design process and enables them to touch and feel the result of their innovative work. The availability of many 3D printers on the market has created a certain level of challenge for the user. Among others, complexity of part geometry, material type, compatibility with 3D CAD models and other technical aspects still need in-depth study. This paper presents results of the experimental work on the capabilities and limitations of the Z510 3D printer from Z-corporation. Several parameters such as dimensional and geometrical accuracy, surface quality and strength as a function of model size, orientation and file exchange format are closely studied.

Lemu, H. G.

2012-04-01

92

Islet amyloid deposition limits the viability of human islet grafts but not porcine islet grafts  

PubMed Central

Islet transplantation is a promising treatment for diabetes but long-term success is limited by progressive graft loss. Aggregates of the beta cell peptide islet amyloid polypeptide (IAPP) promote beta cell apoptosis and rapid amyloid formation occurs in transplanted islets. Porcine islets are an attractive alternative islet source as they demonstrate long-term graft survival. We compared the capacity of transplanted human and porcine islets to form amyloid as an explanation for differences in graft survival. Human islets were transplanted into streptozotocin-diabetic immune-deficient mice. Amyloid deposition was detectable at 4 weeks posttransplantation and was associated with islet graft failure. More extensive amyloid deposition was observed after 8 weeks. By contrast, no amyloid was detected in transplanted neonatal or adult porcine islets that had maintained normoglycemia for up to 195 days. To determine whether differences in IAPP sequence between humans and pigs could explain differences in amyloid formation and transplant viability, we sequenced porcine IAPP. Porcine IAPP differs from the human sequence at 10 positions and includes substitutions predicted to reduce its amyloidogenicity. Synthetic porcine IAPP was considerably less amyloidogenic than human IAPP as determined by transmission electron microscopy, circular dichroism, and thioflavin T binding. Viability assays indicated that porcine IAPP is significantly less toxic to INS-1 beta cells than human IAPP. Our findings demonstrate that species differences in IAPP sequence can explain the lack of amyloid formation and improved survival of transplanted porcine islets. These data highlight the potential of porcine islet transplantation as a therapeutic approach for human diabetes.

Potter, K. J.; Abedini, A.; Marek, P.; Klimek, A. M.; Butterworth, S.; Driscoll, M.; Baker, R.; Nilsson, M. R.; Warnock, G. L.; Oberholzer, J.; Bertera, S.; Trucco, M.; Korbutt, G. S.; Fraser, P. E.; Raleigh, D. P.; Verchere, C. B.

2010-01-01

93

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

94

Deviation of Zipf's and Heaps' Laws in Human Languages with Limited Dictionary Sizes  

PubMed Central

Zipf's law on word frequency and Heaps' law on the growth of distinct words are observed in Indo-European language family, but it does not hold for languages like Chinese, Japanese and Korean. These languages consist of characters, and are of very limited dictionary sizes. Extensive experiments show that: (i) The character frequency distribution follows a power law with exponent close to one, at which the corresponding Zipf's exponent diverges. Indeed, the character frequency decays exponentially in the Zipf's plot. (ii) The number of distinct characters grows with the text length in three stages: It grows linearly in the beginning, then turns to a logarithmical form, and eventually saturates. A theoretical model for writing process is proposed, which embodies the rich-get-richer mechanism and the effects of limited dictionary size. Experiments, simulations and analytical solutions agree well with each other. This work refines the understanding about Zipf's and Heaps' laws in human language systems.

Lu, Linyuan; Zhang, Zi-Ke; Zhou, Tao

2013-01-01

95

Double-pass measurement of human eye aberrations: limitations and practical realization  

NASA Astrophysics Data System (ADS)

The problem of correct eye aberrations measurement is very important with the rising widespread of a surgical procedure for reducing refractive error in the eye, so called, LASIK (laser-assisted in situ keratomileusis). The double-pass technique commonly used for measuring aberrations of a human eye involves some uncertainties. One of them is loosing the information about odd human eye aberrations. We report about investigations of the applicability limit of the double-pass measurements depending upon the aberrations status introduced by human eye and actual size of the entrance pupil. We evaluate the double-pass effects for various aberrations and different pupil diameters. It is shown that for small pupils the double-pass effects are negligible. The testing and alignment of aberrometer was performed using the schematic eye, developed in our lab. We also introduced a model of human eye based on bimorph flexible mirror. We perform calculations to demonstrate that our schematic eye is capable of reproducing spatial-temporal statistics of aberrations of living eye with normal vision or even myopic or hypermetropic or with high aberrations ones.

Letfullin, Renat R.; Belyakov, Alexey I.; Cherezova, Tatyana Y.; Kudryashov, Alexis V.

2004-11-01

96

Adult human heart slices are a multicellular system suitable for electrophysiological and pharmacological studies  

Microsoft Academic Search

Electrophysiological and pharmacological data from the human heart are limited due to the absence of simple but representative experimental model systems of human myocardium. The aim of this study was to establish and characterise adult human myocardial slices from small patients' heart biopsies as a simple, reproducible and relevant preparation suitable for the study of human cardiac tissue at the

Patrizia Camelliti; Sara Abou Al-Saud; Ryszard T. Smolenski; Samha Al-Ayoubi; Alexandra Bussek; Erich Wettwer; Nicholas R. Banner; Christopher T. Bowles; Magdi H. Yacoub; Cesare M. Terracciano

97

The limits for detection of activated caspases of spermatozoa by western blot in human semen.  

PubMed

Detection of activated caspases of spermatozoa could be helpful to evaluate male infertility. Although western blot is validated as a highly specific method to detect the proteins extracted from cells, the ability of this technique to detect activated sperm caspases in human semen may be limited. Indeed, round cells, which potentially contain some activated caspases, may be present in semen and interfere with the detection of activated sperm caspases. Moreover, it is necessary to evaluate the minimum amount of spermatozoa necessary to optimise the detection of activated caspases in semen samples. Our results showed that interference due to round cells contained in semen with activated caspase-3 requires separation of spermatozoa by density migration. This sperm preparation selects a mature sperm population that does not reflect the whole sperm population, and in infertile men with oligoasthenoteratozoospermia, the amount of spermatozoa thus selected is usually low. Moreover, the western blot technique's low detection sensitivity and the low level of caspase enzyme activity in human spermatozoa for activated caspase-3, -8 and -9 mean that large quantities of spermatozoa are needed to detect the expression of the activated caspases. These limitations prevent this method being used for routine analysis in clinical practice. PMID:22292703

Brugnon, F; Pons-Rejraji, H; Artonne, C; Janny, L; Grizard, G

2012-02-01

98

Technical and ethical limitations in making human monoclonal antibodies (an overview).  

PubMed

In the broadest sense there are no longer any technical limitations to making human mAbs. Biological issues involving the type and nature of either a synthetic or a natural antibody, advantages of various B cell immunological compartments, and various assays needed to qualitate and quantitate mAbs have essentially been solved. If the target antigen is known then procedures to optimize antibody development can be readily planned out and implemented. When the antigen or target is unknown and specificity is the driving force in generating a human mAb then considerations about the nature and location of the B cell making the sought after antibody become important. And, therefore, the person the B cell is obtained from can be an ethical challenge and a limitation. For the sources of B cells special considerations must be taken to insure the anonymity and privacy of the patient. In many cases informed consent is adequate for antibody development as well as using discarded tissues. After the antibody has been generated then manufacturing technical issues become important that greatly depend upon the amounts of mAb required. For kilogram quantities then special considerations for manufacturing that include FDA guidelines will be necessary. PMID:24037834

Glassy, Mark C; Gupta, Rishab

2014-01-01

99

From Oxford to Hawaii Ecophysiological Barriers Limit Human Progression in Ten Sport Monuments  

PubMed Central

In order to understand the determinants and trends of human performance evolution, we analyzed ten outdoor events among the oldest and most popular in sports history. Best performances of the Oxford-Cambridge boat race (since 1836), the channel crossing in swimming (1875), the hour cycling record (1893), the Elfstedentocht speed skating race (1909), the cross country ski Vasaloppet (1922), the speed ski record (1930), the Streif down-hill in Kitzbühel (1947), the eastward and westward sailing transatlantic records (1960) and the triathlon Hawaii ironman (1978) all follow a similar evolutive pattern, best described through a piecewise exponential decaying model (r2?=?0.95±0.07). The oldest events present highest progression curvature during their early phase. Performance asymptotic limits predicted from the model may be achieved in fourty years (2049±32 y). Prolonged progression may be anticipated in disciplines which further rely on technology such as sailing and cycling. Human progression in outdoor sports tends to asymptotic limits depending on physiological and environmental parameters and may temporarily benefit from further technological progresses.

Desgorces, Francois-Denis; Berthelot, Geoffroy; El Helou, Nour; Thibault, Valerie; Guillaume, Marion; Tafflet, Muriel; Hermine, Olivier; Toussaint, Jean-Francois

2008-01-01

100

Ca2+-activated K+ efflux limits complement-mediated lysis of human erythrocytes.  

PubMed Central

The lytic effect of complement on human erythrocytes has been reported by others to increase when Na+ is substituted for K+ in the external medium. In this paper we have investigated the hypothesis that net loss of K+ through a K+ transport pathway protects erythrocytes from complement-induced colloidosmotic swelling and lysis. Antibody-sensitized human erythrocytes containing different intracellular cation concentrations (nystatin treatment) were exposed to low concentrations of guinea pig serum in media of different cation composition; complement lysis was assessed by the release of hemoglobin and the volume of the surviving cells estimated by their density distribution profiles. Complement-dependent swelling and lysis of erythrocytes (a) were limited by the presence of an outwardly directed K+ electrochemical gradient and (b) were enhanced by carbocyanine, a specific inhibitor of the Ca2+-activated K+ transport pathway, and by absence of Ca2+ in the external medium. We propose that during complement activation a rising cytosolic calcium triggers the Ca2+-activated K+ permeability pathway, the Gardos effect, produces a net K+, Cl- and water loss, and thus limits the colloidosmotic swelling and lysis of erythrocytes.

Halperin, J A; Brugnara, C; Nicholson-Weller, A

1989-01-01

101

From Oxford to Hawaii ecophysiological barriers limit human progression in ten sport monuments.  

PubMed

In order to understand the determinants and trends of human performance evolution, we analyzed ten outdoor events among the oldest and most popular in sports history. Best performances of the Oxford-Cambridge boat race (since 1836), the channel crossing in swimming (1875), the hour cycling record (1893), the Elfstedentocht speed skating race (1909), the cross country ski Vasaloppet (1922), the speed ski record (1930), the Streif down-hill in Kitzbühel (1947), the eastward and westward sailing transatlantic records (1960) and the triathlon Hawaii ironman (1978) all follow a similar evolutive pattern, best described through a piecewise exponential decaying model (r(2) = 0.95+/-0.07). The oldest events present highest progression curvature during their early phase. Performance asymptotic limits predicted from the model may be achieved in fourty years (2049+/-32 y). Prolonged progression may be anticipated in disciplines which further rely on technology such as sailing and cycling. Human progression in outdoor sports tends to asymptotic limits depending on physiological and environmental parameters and may temporarily benefit from further technological progresses. PMID:18985149

Desgorces, François-Denis; Berthelot, Geoffroy; El Helou, Nour; Thibault, Valérie; Guillaume, Marion; Tafflet, Muriel; Hermine, Olivier; Toussaint, Jean-François

2008-11-05

102

Placing confidence limits on the molecular age of the human-chimpanzee divergence  

PubMed Central

Molecular clocks have been used to date the divergence of humans and chimpanzees for nearly four decades. Nonetheless, this date and its confidence interval remain to be firmly established. In an effort to generate a genomic view of the human–chimpanzee divergence, we have analyzed 167 nuclear protein-coding genes and built a reliable confidence interval around the calculated time by applying a multifactor bootstrap-resampling approach. Bayesian and maximum likelihood analyses of neutral DNA substitutions show that the human–chimpanzee divergence is close to 20% of the ape–Old World monkey (OWM) divergence. Therefore, the generally accepted range of 23.8–35 millions of years ago for the ape–OWM divergence yields a range of 4.98–7.02 millions of years ago for human–chimpanzee divergence. Thus, the older time estimates for the human–chimpanzee divergence, from molecular and paleontological studies, are unlikely to be correct. For a given the ape–OWM divergence time, the 95% confidence interval of the human–chimpanzee divergence ranges from –12% to 19% of the estimated time. Computer simulations suggest that the 95% confidence intervals obtained by using a multifactor bootstrap-resampling approach contain the true value with >95% probability, whether deviations from the molecular clock are random or correlated among lineages. Analyses revealed that the use of amino acid sequence differences is not optimal for dating human–chimpanzee divergence and that the inclusion of additional genes is unlikely to narrow the confidence interval significantly. We conclude that tests of hypotheses about the timing of human–chimpanzee divergence demand more precise fossil-based calibrations.

Kumar, Sudhir; Filipski, Alan; Swarna, Vinod; Walker, Alan; Hedges, S. Blair

2005-01-01

103

Energy Aware Computing through Probabilistic Switching: A Study of Limits  

Microsoft Academic Search

The mathematical technique of randomization yielding probabilistic algorithms is shown, for the first time, through a physical interpretation based on statistical thermodynamics, to be a basis for energy savings in computing. Concretely, at the fundamental limit, it is shown that the energy needed to compute a single probabilistic bit or PBIT is proportional to the probability p of computing a

Krishna V. Palem

2005-01-01

104

The limits of localization using signal strength: a comparative study  

Microsoft Academic Search

We characterize the fundamental limits of localization using signal strength in indoor environments. Signal strength approaches are attractive because they are widely applicable to wireless sensor networks and do not require additional localization hardware. We show that although a broad spectrum of algorithms can trade accuracy for precision, none has a significant advantage in localization performance. We found that using

Eiman Elnahrawy; Xiaoyan Li; Richard P. Martin

2004-01-01

105

Human head tolerance limits to specific injury mechanisms inferred from real world accident numerical reconstruction  

Microsoft Academic Search

This study presents an original numerical human head model which is validated in both modal and temporal domain against vibration analysis in vivo and cadaver impact tests. The head finite element model developed presents two particularities : one at the interface between the brain and the skull were fluid structure interaction is taken into account, the other at the skull

Daniel Baumgartner; Rémy Willinger

2005-01-01

106

Proposing a better forming limit diagram prediction: a comparative study  

Microsoft Academic Search

In this work, it is shown an algorithm for the prediction of the right-hand side of forming limit diagram (FLD) using the methodology proposed by Marciniak and Kuczynski. Five different yield criteria were used: von Mises’, Hill’s (1948), Hill’s (1979), Logan and Hosford’s, and Hill’s (1993) [Metal Forming—Mechanics and Metallurgy, 2nd ed., Prentice-Hall, Englewood Cliffs, NJ, 1993; Proc. R. Soc.

Antonio F. Ávila; Evânio L. S. Vieira

2003-01-01

107

Limitations to CO 2 -induced growth enhancement in pot studies  

Microsoft Academic Search

Recently, it has been suggested that small pots may reduce or eliminate plant responses to enriched CO2 atmospheres due to root restriction. While smaller pot volumes provide less physical space available for root growth, they\\u000a also provide less nutrients. Reduced nutrient availability alone may reduce growth enhancement under elevated CO2. To investigate the relative importance of limited physical rooting space

K. D. M. McConnaughay; G. M. Berntson; F. A. Bazzaz

1993-01-01

108

Estimation of the upper limit of human butyrylcholinesterase dose required for protection against organophosphates toxicity: a mathematically based toxicokinetic model.  

PubMed

Human butyrylcholinesterase (HuBChE) is a drug candidate for protection against organophosphates (OP) intoxication. A mathematically based model was validated and employed to better understand the role of the endogenous HuBChE in detoxification of OPs and to estimate the dose of exogenous HuBChE required for enhancing protection of humans from lethal exposure to OPs. The model addresses the relationship between the HuBChE dose needed to maintain a certain residual activity of human acetylcholinesterase (HuAChE) and the following parameters: (1) level and duration of exposure, (2) bimolecular rate constants of inhibition of HuAChE (kA) and HuBChE (kB) by OPs, and (3) time elapsed from enzyme load. The equation derived for the calculation of HuBChE dose requires the knowledge of kA/kB in human blood and the rate constant of HuBChE elimination. Predictions of HuBChE doses were validated by in vitro experiments and data of published human studies. These predictions highlight two parameters that are likely to decrease the calculated dose: (1) the rapid consumption of the less toxic isomers of OPs in human plasma, and (2) the volume of distribution of HuBChE that appears significantly greater than the volume of plasma. The first part of the analysis of the proposed model was focused on acute bolus exposures and suggests that upper limit doses of 134, 115, and 249 mg/70 kg are sufficient to protect RBC AChE above 30% of baseline activity following a challenge with 1 LD(50) VX, soman, and sarin, respectively. The principles of the validated model should be applicable for advanced predictions of HuBChE dose for protection against continuous exposures to OPs. PMID:14600276

Ashani, Yacov; Pistinner, Shlomi

2003-11-04

109

Humanized Immune System (HIS) Mice as a Tool to Study Human NK Cell Development  

Microsoft Academic Search

The study of human hematopoiesis is conditioned by access to nondiseased human tissue samples that harbor the cellular substrates\\u000a for this developmental process. Technical and ethical concerns limit the availability to tissues derived from the fetal and\\u000a newborn periods, while adult samples are generally restricted to peripheral blood. Access to a small animal model that faithfully\\u000a recapitulates the process of

N. D. Huntington; J. P. Di Santo

110

Telomeres at the chromosome X p might be critical in limiting the proliferative potential of human cells  

Microsoft Academic Search

Normal human somatic cells can only divide for a limited number of times. This phenomenon has been regarded as a reflection of individual aging at the cellular level. Experimental evidences suggest that a cell's division potential is limited by the physical length of telomeres that gradually shorten through successive cell divisions. At present, it is not clear whether such a

Yu-hua Hao; Zheng Tan

2001-01-01

111

Viral Studies in Humans and Other Primates.  

National Technical Information Service (NTIS)

All aspects of human and other primate (gibbon, ape, marmoset, chimpanzee, baboon, lemur, monkey) viruses of interest to cancer researchers are within the scope of this Cancergram. Only studies carried out in human and other primate cells will be included...

1983-01-01

112

Virus Studies in Humans and Other Primates.  

National Technical Information Service (NTIS)

All aspects of human and other primate (gibbon, ape, marmoset, chimpanzee, baboon, lemur, monkey) viruses of interest to cancer researchers are within the scope of this Cancergram. Only studies carried out in human and other primate cells will be included...

1980-01-01

113

Viral Studies in Humans and Other Primates.  

National Technical Information Service (NTIS)

All aspects of human and other primate (gibbon, ape, marmoset, chimpanzee, baboon, lemur, monkey) viruses of interest to cancer researchers are within the scope of this Cancergram. Only studies carried out in human and other primate cells will be included...

1985-01-01

114

Virus Studies in Humans and Other Primates.  

National Technical Information Service (NTIS)

All aspects of human and other primate (gibbon, ape, marmoset, chimpanzee, baboon, lemur, monkey) viruses of interest to cancer researchers are within the scope of this Cancergram. Only studies carried out in human and other primate cells will be included...

1979-01-01

115

Viral Studies in Humans and Other Primates.  

National Technical Information Service (NTIS)

All aspects of human and other primate (gibbon, ape, marmoset, chimpanzee, baboon, lemur, monkey) viruses of interest to cancer researchers are within the scope of this Cancergram. Only studies carried out in human and other primate cells will be included...

1984-01-01

116

Virus Studies in Humans and Other Primates.  

National Technical Information Service (NTIS)

All aspects of human and other primate (gibbon, ape, marmoset, chimpanzee, baboon, lemur, monkey) viruses of interest to cancer researchers are within the scope of this Cancergram. Only studies carried out in human and other primate cells will be included...

1982-01-01

117

Creation of "Humanized" Mice to Study Human Immunity  

PubMed Central

Humanized” mice are a promising translational model for studying human hematopoiesis and immunity. Their utility has been enhanced by the development of new stocks of immunodeficient hosts, most notably mouse strains such as NOD-scid IL2r? null mice that lack the IL-2 receptor common gamma chain. These stocks of mice lack adaptive immune function, display multiple defects in innate immunity, and support heightened levels of human hematolymphoid engraftment. Humanized mice can support studies in many areas of immunology, including autoimmunity, transplantation, infectious diseases, and cancer. These models are particularly valuable in experimentation where there is no appropriate small animal model of the human disease, as in the case of certain viral infections. This unit details the creation of humanized mice by engraftment of immunodeficient mice with hematopoietic stem cells or peripheral blood mononuclear cells, provides methods for evaluating engraftment, and discusses considerations for choosing the appropriate model system to meet specific goals.

Pearson, Todd; Greiner, Dale L.; Shultz, Leonard D.

2010-01-01

118

On the generality and limits of abstraction in rats and humans  

PubMed Central

In this review, we address the question, central to cognition, of whether nonhuman animals such as rats are capable of extracting and extending information from a given learning situation to a new learning situation without generalizing through a physical dimension of the stimuli. This capacity underlies abstraction, which is a hallmark of human cognition and necessary for complex information processing such as language acquisition. We selectively review recent experiments with rats in which systematic changes in information processing of new stimuli are observed after training with different stimuli. These results strongly suggest that this capacity is present in rats. We also review two articles in which clear limitations to this capacity are detected. We conclude that, within specified limits, rats are capable of using prior experience when faced with a learning situation that involves new stimuli. We interpret this ability as a rudimentary form of abstraction. In the face of these provocative results, new theories of learning should be designed to account for these findings.

Miller, Ralph R.

2010-01-01

119

Human Stereopsis is not Limited by the Optics of the Well-focused Eye  

PubMed Central

Human stereopsis—the perception of depth from differences in the two eyes’ images—is very precise: Image differences smaller than a single photoreceptor can be converted into a perceived difference in depth. To better understand what determines this precision, we examined how the eyes’ optics affects stereo resolution. We did this by comparing performance with normal, well-focused optics and with optics improved by eliminating chromatic aberration and correcting higher-order aberrations. We first measured luminance contrast sensitivity in both eyes and showed that we had indeed improved optical quality significantly. We then measured stereo resolution in two ways: by finding the finest corrugation in depth that one can perceive, and by finding the smallest disparity one can perceive as different from zero. Our optical manipulation had no effect on stereo performance. We checked this by redoing the experiments at low contrast and again found no effect of improving optical quality. Thus, the resolution of human stereopsis is not limited by the optics of the well-focused eye. We discuss the implications of this remarkable finding.

Vlaskamp, Bjorn N.S.; Yoon, Geunyoung; Banks, Martin S.

2011-01-01

120

Animal carcinogenicity studies: 1. Poor human predictivity.  

PubMed

The regulation of human exposure to potentially carcinogenic chemicals constitutes society's most important use of animal carcinogenicity data. Environmental contaminants of greatest concern within the USA are listed in the Environmental Protection Agency's (EPA's) Integrated Risk Information System (IRIS) chemicals database. However, of the 160 IRIS chemicals lacking even limited human exposure data but possessing animal data that had received a human carcinogenicity assessment by 1 January 2004, we found that in most cases (58.1%; 93/160), the EPA considered animal carcinogenicity data inadequate to support a classification of probable human carcinogen or non-carcinogen. For the 128 chemicals with human or animal data also assessed by the World Health Organisation's International Agency for Research on Cancer (IARC), human carcinogenicity classifications were compatible with EPA classifications only for those 17 having at least limited human data (p = 0.5896). For those 111 primarily reliant on animal data, the EPA was much more likely than the IARC to assign carcinogenicity classifications indicative of greater human risk (p < 0.0001). The IARC is a leading international authority on carcinogenicity assessments, and its significantly different human carcinogenicity classifications of identical chemicals indicate that: 1) in the absence of significant human data, the EPA is over-reliant on animal carcinogenicity data; 2) as a result, the EPA tends to over-predict carcinogenic risk; and 3) the true predictivity for human carcinogenicity of animal data is even poorer than is indicated by EPA figures alone. The EPA policy of erroneously assuming that tumours in animals are indicative of human carcinogenicity is implicated as a primary cause of these errors. PMID:16522147

Knight, Andrew; Bailey, Jarrod; Balcombe, Jonathan

2006-02-01

121

Hanford study: a review of its limitations and controversial conclusions  

SciTech Connect

The Hanford data set has attracted attention primarily because of analyses conducted by Mancuso, Stewart, and Kneale (MSK). These investigators claim that the Hanford data provide evidence that our current estimates of cancer mortality resulting from radiation exposure are too low, and advocate replacing estimates based on populations exposed at relatively high doses (such as the Japanese atom bomb survivors) with estimates based on the Hanford data. In this paper, it is shown that the only evidence of association of radiation exposure and mortality provided by the Hanford data is a small excess of multiple myeloma, and that this data set is not adequate for reliable risk estimation. It is demonstrated that confidence limits for risk estimates are very wide, and that the data are not adequate to differentiate among models. The more recent MSK analyses, which claim to provide adequate models and risk estimates, are critiqued. 18 references, 1 table.

Gilbert, E.S.

1984-10-01

122

Cultural Studies and the Limits of Self-Reflexivity.  

ERIC Educational Resources Information Center

Among the changes that have characterized English studies over the past 25 years is an increase in self-reflection. The rise of various kinds of writing collectively labeled "theory" has influenced this move to scrutinize actions and motives. Composition studies have developed classroom strategies for asking students to reflect on their own…

Knapp, James F.

123

On limiting the narrative paradigm: Three case studies  

Microsoft Academic Search

While narrative is studied in any number of fields as a form of discourse, only in communication studies has it been claimed that all forms of discourse can be viewed as types of narrative. One way of testing such an all?encompassing interpretation of narrative is to apply the assumptions of the narrative paradigm to works that traditionalists would not consider

Robert C. Rowland

1989-01-01

124

critcial human health issues in connection with future human missions to mMars: the HUMEX study of ESA  

Microsoft Academic Search

ESA has recently initiated a study of the human responses, limits and needs with regard to the stress environments of interplanetary and planetary missions. Emphasis was laid on human health and performance care as well as Advanced Life Support Developments including Bioregenerative Life Support Systems and environmental monitoring. The overall study goals were as follows: (i) to define reference scenarios

G. Horneck

2004-01-01

125

Limited effects of ?-endorphin compared to loperamide or fentanyl in a neuroendocrine biomarker assay in non-human primates  

PubMed Central

Summary The in vivo pharmacodynamics of the opioid neuropeptide ?–endorphin (a major endogenous agonist at the ?-opioid receptor) are difficult to determine in non human primate models with translational value, or in humans. The present studies therefore employed a neuroendocrine biomarker assay, prolactin release, to systematically compare the in vivo profile of i.v. ?-endorphin (0.01–0.32 mg/kg; i.v.) in gonadally intact male rhesus monkeys (n=4) to that of the peripherally selective ?-agonist loperamide (0.01–0.32 mg/kg; i.v.) and the centrally-penetrating ?-agonist fentanyl (0.0056–0.018 mg/kg; i.v.). Studies utilized a standardized time course design (measuring prolactin levels 5–120 min after agonist administration).?-endorphin displayed only limited effectiveness in causing prolactin release when tested over this 30-fold dose range, compared to loperamide or fentanyl. Furthermore, two of the four subjects were only minimally responsive to ?-endorphin. This differential responsiveness was not due to the presence of a previously described single nucleotide polymorphism at the OPRM1 gene (C77G), known to affect ?-endorphin pharmacodynamics in vitro. In vivo biotransformation studies with MALDI mass spectrometry determined that full length ?-endorphin was detectable in all subjects up to at least 5 min after i.v. administration. Thus, the relative ineffectiveness of i.v. ?-endorphin in this assay does not appear to be principally due to rapid generation of non-opioid fragments of this neuropeptide.

Butelman, Eduardo R.; Reed, Brian; Chait, Brian T.; Mandau, Marek; Yuferov, Vadim; Kreek, Mary Jeanne

2008-01-01

126

Limited ability to extend the digits of the human hand independently with extensor digitorum  

PubMed Central

While the human hand has an extraordinary capacity to manipulate objects, movement of its digits is usually not completely independent. These limits have been documented for extrinsic flexor muscles, although hand skills also require selectivity for extension movements. Hence, we measured the degree of independent control of the major extrinsic extensor (extensor digitorum, ED). Subjects grasped a cylinder, with the thumb perpendicular to the fingers. Load cells were connected to the proximal phalanges of the fingers and the thumb's distal phalanx. Intramuscular recordings using needle electrodes were made from the individual digital compartments of ED. Subjects were instructed to extend each digit isometrically in a voluntary ramp contraction to 50% maximal force. In total, the behaviour of 283 single motor units was analysed. More than half of the units associated with one ‘test’ finger were recruited inadvertently when another digit contracted to 50% maximum, with most units being recruited by extension of the adjacent digits. Usually, test motor units were recruited at higher forces by extension of fingers further from the test finger. Unexpectedly, extension of the thumb recruited many motor units acting on the little finger. Across tasks, at recruitment of the test motor units, the force produced by the test finger often differed between the voluntary and inadvertent contractions. Overall, the independent control of the output of ED is limited; this may reflect ‘spill-over’ of motor commands to other digital extensor compartments. This level of control of the extrinsic extensor muscles is more independent than the control of the deep extrinsic flexor muscle but less independent than that of the superficial extrinsic flexor muscle.

van Duinen, Hiske; Yu, Wei Shin; Gandevia, Simon C

2009-01-01

127

EELS detection limits revisited: Ruby — a case study  

Microsoft Academic Search

Theoretical and experimental EELS studies have been performed to optimize the chromium (Cr) quantification in natural ruby, featuring low concentrations of Cr in alumina (Al2O3).First, the noise performance of the detection system was determined (MTF, DQE), having been vastly underestimated in literature, as there was hardly any consideration of the dose dependence on the DQE. The superiority of the MLLS

Katharina Riegler; Gerald Kothleitner

2010-01-01

128

Studies on the human choroid plexus in vitro.  

PubMed

The role of human choroid plexus (CP) epithelium in the transport of solutes between the blood and the cerebrospinal fluid and/or in secretion processes may be studied by employing several experimental approaches. There are a number of in vitro techniques for human CP epithelium (CPE) and all have limitations that do not exclude them a priori, but that should be carefully taken into consideration. Developmental and morphological studies have been largely performed on human choroid plexus samples of either embryonic or post-mortem origin. Functional uptake studies may be performed on pathologically unaltered CP samples obtained during surgical removal of choroid plexus tumors. This approach can be used to explore transport processes mainly across the apical side of the CPE, but cannot be used to study vectorial transport across the CPE. Also, these samples have limited viability. A monolayer of CPE in culture, grown on permeable supports, provides the best available tool to study transport processes or polarized secretion by the CP, but thus far only limited attempts to culture these cells have been published and they mainly include data from neoplastic CPE. A study that used a human papilloma-derived cell line in culture showed that it forms a monolayer with barrier properties, although the cells express pleomorphic and neoplastic features and lack contact inhibition. Other cell cultures express some CPE markers but do not develop tight junctions/barrier properties. This article reviews the main characteristics and limitations of available in vitro methods to study human CPE, which could help researchers choose an appropriate experimental approach for a particular study. PMID:23391221

Redzic, Zoran B

2013-02-07

129

Studies on the human choroid plexus in vitro  

PubMed Central

The role of human choroid plexus (CP) epithelium in the transport of solutes between the blood and the cerebrospinal fluid and/or in secretion processes may be studied by employing several experimental approaches. There are a number of in vitro techniques for human CP epithelium (CPE) and all have limitations that do not exclude them a priori, but that should be carefully taken into consideration. Developmental and morphological studies have been largely performed on human choroid plexus samples of either embryonic or post-mortem origin. Functional uptake studies may be performed on pathologically unaltered CP samples obtained during surgical removal of choroid plexus tumors. This approach can be used to explore transport processes mainly across the apical side of the CPE, but cannot be used to study vectorial transport across the CPE. Also, these samples have limited viability. A monolayer of CPE in culture, grown on permeable supports, provides the best available tool to study transport processes or polarized secretion by the CP, but thus far only limited attempts to culture these cells have been published and they mainly include data from neoplastic CPE. A study that used a human papilloma-derived cell line in culture showed that it forms a monolayer with barrier properties, although the cells express pleomorphic and neoplastic features and lack contact inhibition. Other cell cultures express some CPE markers but do not develop tight junctions/barrier properties. This article reviews the main characteristics and limitations of available in vitro methods to study human CPE, which could help researchers choose an appropriate experimental approach for a particular study.

2013-01-01

130

Studies of Human Mutation Rates: Progress Report.  

National Technical Information Service (NTIS)

Progress was recorded between January 1 and July 1, 1987 on a project entitled ''Studies of Human Mutation Rates''. Studies underway include methodology for studying mutation at the DNA level, algorithms for automated analyses of two-dimensional polyacryl...

J. V. Neel

1988-01-01

131

Chromosomal integration of adeno-associated parvovirus DNA limits proliferation and dispersal of human MKr melanoma cells in co-cultures with human fibroblasts.  

PubMed

Adeno-associated parvoviruses (AAVs) possess onco-suppressive potential and inhibit proliferation of cells derived from malignant human tumors in culture. Growth inhibition of human melanoma cells can be achieved when the cells are infected with these viruses but continues subsequent to infection when viral DNA is chromosomally integrated. Integration of AAV2 DNA into the genome of the human melanoma cell line MKr alters the cellular phenotype towards that of diploid cells in culture, and leads to density-arrested growth, strong reduction of the ability to form colonies from single cells and to an increased number of terminally differentiating cultures. The present study aimed at the question whether the altered growth properties were retained upon prolonged co-cultivation with fibroblasts, i.e. under conditions that occur in invasive growth and colonization of distant tissues. The results show that despite the known possibility of growth stimulation by fibroblasts the potential of melanoma cells to proliferate and the potential to further scatter in the fibroblast cultures remain limited when AAV DNA is integrated. PMID:10660088

Bantel-Schaal, U

1999-12-01

132

Evidence of a molecular barrier limiting susceptibility of humans, cattle and sheep to chronic wasting disease  

PubMed Central

Chronic wasting disease (CWD) is a transmissible spongiform encephalopathy (TSE) of deer and elk, and little is known about its transmissibility to other species. An important factor controlling interspecies TSE susceptibility is prion protein (PrP) homology between the source and recipient species/genotypes. Furthermore, the efficiency with which the protease-resistant PrP (PrP-res) of one species induces the in vitro conversion of the normal PrP (PrP-sen) of another species to the protease-resistant state correlates with the cross-species transmissibility of TSE agents. Here we show that the CWD-associated PrP-res (PrPCWD) of cervids readily induces the conversion of recombinant cervid PrP-sen molecules to the protease-resistant state in accordance with the known transmissibility of CWD between cervids. In contrast, PrPCWD-induced conversions of human and bovine PrP-sen were much less efficient, and conversion of ovine PrP-sen was intermediate. These results demonstrate a barrier at the molecular level that should limit the susceptibility of these non-cervid species to CWD.

Raymond, G.J.; Bossers, A.; Raymond, L.D.; O'Rourke, K.I.; McHolland, L.E.; Bryant III, P.K.; Miller, M.W.; Williams, E.S.; Smits, M.; Caughey, B.

2000-01-01

133

Pharmacogenetics Studies in STAR*D: Strengths, Limitations, and Results  

PubMed Central

Several lines of evidence support an important genetic contribution to the wide individual variation in therapeutic response to antidepressant medications. The Sequenced Treatment Alternatives to Relieve Depression (STAR*D) study provided the largest cohort assembled to date of DNA from patients with nonpsychotic major depressive disorder, uniformly treated with citalopram and followed prospectively for up to 12 weeks. This pivotal study changed the face of pharmacogenetics research by increasing the sample size by an order of magnitude as well as by providing detailed prospective information about antidepressant response and tolerability. Several groups have identified markers in genes and tested the replication of previous findings of genes associated with outcome and side effects of antidepressant treatment. Variants in HTR2A, GRIK4, and KCNK2 were associated with citalopram treatment outcome. Replication was achieved in markers in the FKBP5 gene. Other findings in PDE11A and BDNF were not successfully replicated, and reports of potential confounders in previous associations with serotonin transporter variation (SLC6A4) were identified. Polymorphisms in pharmacokinetic genes involved in metabolism and transmembrane transport were also not associated with antidepressant response. Adverse events were also tested. Treatment-emergent suicidal ideation was associated with GRIK2, GRIA3, PAPLN, IL28RA, and CREB1. Sexual dysfunction was linked with variation in GRIN3A, GRIA1 GRIA3, and GRIK2. Reported and future findings of pharmacogenetics studies in STAR*D could help elucidate pathways involved in major depression and those pertinent to antidepressant outcome and side effects. Replication of these findings in independent samples could lead to the development of new treatments and to optimization of available treatments.

Laje, Gonzalo; Perlis, Roy H.; Rush, A. John; McMahon, Francis J.

2013-01-01

134

Pharmacogenetics studies in STAR*D: strengths, limitations, and results.  

PubMed

Several lines of evidence support an important genetic contribution to the wide individual variation in therapeutic response to antidepressant medications. The Sequenced Treatment Alternatives to Relieve Depression (STAR*D) study provided the largest cohort assembled to date of DNA from patients with nonpsychotic major depressive disorder, uniformly treated with citalopram and followed prospectively for up to 12 weeks. This pivotal study changed the face of pharmacogenetics research by increasing the sample size by an order of magnitude as well as by providing detailed prospective information about antidepressant response and tolerability. Several groups have identified markers in genes and tested the replication of previous findings of genes associated with outcome and side effects of antidepressant treatment. Variants in HTR2A, GRIK4, and KCNK2 were associated with citalopram treatment outcome. Replication was achieved in markers in the FKBP5 gene. Other findings in PDE11A and BDNF were not successfully replicated, and reports of potential confounders in previous associations with serotonin transporter variation (SLC6A4) were identified. Polymorphisms in pharmacokinetic genes involved in metabolism and transmembrane transport were also not associated with antidepressant response. Adverse events were also tested. Treatment-emergent suicidal ideation was associated with GRIK2, GRIA3, PAPLN, IL28RA, and CREB1. Sexual dysfunction was linked with variation in GRIN3A, GRIA1 GRIA3, and GRIK2. Reported and future findings of pharmacogenetics studies in STAR*D could help elucidate pathways involved in major depression and those pertinent to antidepressant outcome and side effects. Replication of these findings in independent samples could lead to the development of new treatments and to optimization of available treatments. PMID:19880459

Laje, Gonzalo; Perlis, Roy H; Rush, A John; McMahon, Francis J

2009-11-01

135

A limited bibliography of the federal government-funded human radiation experiments  

SciTech Connect

From the early 1940`s thousands of U.S. citizens have been the subjects of federally supported scientific experiments that involved the administration of ionizing radiation or radioactive substances. Recently, many questions have been raised regarding the nature, scientific value, and ethics of these experiments. Although the results of many of the early human experiments involving radiation have been crucial to the establishment of nuclear medicine, radiation therapy, and radiological protection standards, the underlying ethical basis for a small number of these studies is being questioned. A thorough analysis of these studies and their ethical basis is beyond the scope of this article. Rather, in order to quickly provide the health physics community with some of the available resources in the open literature, a list of bibliographic citations of the 47 studies primarily funded by the Atomic Energy Commission (AEC) and other predecessors of the Department of Energy is presented and briefly summarized. A classification scheme for the human radiation experiments is also developed.

Samei, E.; Kearfott, K.J. [Univ. of Michigan, Ann Arbor, MI (United States)

1995-12-01

136

Potential Limitations of the NSG Humanized Mouse as a Model System to Optimize Engineered Human T cell Therapy for Cancer.  

PubMed

Abstract The genetic modification of peripheral blood lymphocytes using retroviral vectors to redirect T cells against tumor cells has been recently used as a means to generate large numbers of antigen-specific T cells for adoptive cell therapy protocols. However, commonly used retroviral vector-based genetic modification requires T cells to be driven into cell division; this potent mitogenic stimulus is associated with the development of an effector phenotype that may adversely impact upon the long-term engraftment potential and subsequent antitumor effects of T cells. To investigate whether the cytokines used during culture impact upon the engraftment potential of gene-modified T cells, a humanized model employing T cells engrafted with a MART-1-specific T cell receptor adoptively transferred into NOD/Shi-scid IL-2r?(-/-) (NSG) immune-deficient mice bearing established melanoma tumors was used to compare the effects of the common ? chain cytokines IL-2, IL-7, and IL-15 upon gene-modified T cell activity. MART-1-specific T cells cultured in IL-7 and IL-15 demonstrated greater relative in vitro proliferation and viability of T cells compared with the extensively used IL-2. Moreover, the IL-15 culture prolonged the survival of animals bearing melanoma tumors after adoptive transfer. However, the combination of IL-7 and IL-15 produced T cells with improved engraftment potential compared with IL-15 alone; however, a high rate of xenogeneic graft-versus-host disease prevented the identification of a clear improvement in antitumor effect of these T cells. These results clearly demonstrate modulation of gene-modified T cell engraftment in the NSG mouse, which supports the future testing of the combination of IL-7 and IL-15 in adoptive cell therapy protocols; however, this improved engraftment is also associated with the long-term maintenance of xenoreactive T cells, which limits the ultimate usefulness of the NSG mouse model in this situation. PMID:23931270

Alcantar-Orozco, Erik M; Gornall, Hannah; Baldan, Vania; Hawkins, Robert E; Gilham, David E

2013-08-24

137

Pushing the limits of in vivo diffusion MRI for the Human Connectome Project.  

PubMed

Perhaps more than any other "-omics" endeavor, the accuracy and level of detail obtained from mapping the major connection pathways in the living human brain with diffusion MRI depend on the capabilities of the imaging technology used. The current tools are remarkable; allowing the formation of an "image" of the water diffusion probability distribution in regions of complex crossing fibers at each of half a million voxels in the brain. Nonetheless our ability to map the connection pathways is limited by the image sensitivity and resolution, and also the contrast and resolution in encoding of the diffusion probability distribution. The goal of our Human Connectome Project (HCP) is to address these limiting factors by re-engineering the scanner from the ground up to optimize the high b-value, high angular resolution diffusion imaging needed for sensitive and accurate mapping of the brain's structural connections. Our efforts were directed based on the relative contributions of each scanner component. The gradient subsection was a major focus since gradient amplitude is central to determining the diffusion contrast, the amount of T2 signal loss, and the blurring of the water PDF over the course of the diffusion time. By implementing a novel 4-port drive geometry and optimizing size and linearity for the brain, we demonstrate a whole-body sized scanner with G(max) = 300 mT/m on each axis capable of the sustained duty cycle needed for diffusion imaging. The system is capable of slewing the gradient at a rate of 200 T/m/s as needed for the EPI image encoding. In order to enhance the efficiency of the diffusion sequence we implemented a FOV shifting approach to Simultaneous MultiSlice (SMS) EPI capable of unaliasing 3 slices excited simultaneously with a modest g-factor penalty allowing us to diffusion encode whole brain volumes with low TR and TE. Finally we combine the multi-slice approach with a compressive sampling reconstruction to sufficiently undersample q-space to achieve a DSI scan in less than 5 min. To augment this accelerated imaging approach we developed a 64-channel, tight-fitting brain array coil and show its performance benefit compared to a commercial 32-channel coil at all locations in the brain for these accelerated acquisitions. The technical challenges of developing the over-all system are discussed as well as results from SNR comparisons, ODF metrics and fiber tracking comparisons. The ultra-high gradients yielded substantial and immediate gains in the sensitivity through reduction of TE and improved signal detection and increased efficiency of the DSI or HARDI acquisition, accuracy and resolution of diffusion tractography, as defined by identification of known structure and fiber crossing. PMID:23707579

Setsompop, K; Kimmlingen, R; Eberlein, E; Witzel, T; Cohen-Adad, J; McNab, J A; Keil, B; Tisdall, M D; Hoecht, P; Dietz, P; Cauley, S F; Tountcheva, V; Matschl, V; Lenz, V H; Heberlein, K; Potthast, A; Thein, H; Van Horn, J; Toga, A; Schmitt, F; Lehne, D; Rosen, B R; Wedeen, V; Wald, L L

2013-05-24

138

Activity limitations among young adults with developmental disabilities: A population-based follow-up study  

Microsoft Academic Search

Developmental disabilities are a heterogeneous group of chronic conditions that may result in substantial activity limitations. The type and number of limitations may vary by impairment characteristics. Economic and social constraints may impact activity limitations beyond those attributable to their impairment. Using the International Classification of Functioning (ICF), Disability, and Health conceptual framework, this study tests the hypothesis that activity

Kim Van Naarden Braun; Marshalyn Yeargin-Allsopp; Donald Lollar

2009-01-01

139

EMTP RV-based study of solid-state fault current limiter for distribution systems  

Microsoft Academic Search

A fault current limiter (FCL) can reduce the fault current in a feeder system to a desired level and permit continuous power to be fed to loads. An EMTP RV based study to limit fault currents in a distribution system using a solid-state fault current limiter (SSFCL) is presented in this paper. For demonstration purposes, two types of distribution systems

V. K. Sood; R. Amin

2006-01-01

140

Biochemical limitations to high-level expression of humanized monoclonal antibodies in transgenic maize seed endosperm.  

PubMed

Transgenic plants are potentially valuable systems for the large scale manufacture of therapeutic proteins. To improve this technology, determining the importance of transgene transcript levels on protein accumulation in sink tissues during their development is crucial. In transgenic maize (Zea mays L.) plants expressing humanized monoclonal antibodies (mAbs) in their seed endosperm, steady-state kappa light chain (LC) and gamma heavy chain (HC) mRNA levels were quantified during development and compared to the levels of fully-assembled mAb protein present at seed maturity. RNA blots and non-reducing SDS-PAGE western immunoblots revealed that steady-state LC and HC mRNA and protein levels were undetectable at 10 days after pollination (DAP) but increased quickly thereafter in three transgenic events expressing different mAb molecules. Similar to gamma-zein mRNA, LC and HC messages were highly abundant between 15 and 25 DAP. Quantitative RNA blots and western immunoblots showed that steady-state LC transcript levels during development correlated extremely closely with protein levels in mature seed (r(2)=0.99). For HC, this correlation was not as strong (r(2)=0.85). Consistent with this finding, concomitantly increasing the zygosity levels of the LC and HC transgenes enhanced mAb concentration in mature seed, in contrast to increasing the copy number of the transgene insert, which did not correlate with high seed mAb levels. The results indicate that high-level expression of fully-assembled mAb protein in maize endosperm was favored by high LC and HC mRNA levels and was largely limited by HC protein concentration. PMID:16842925

Law, R David; Russell, Douglas A; Thompson, Lisa C; Schroeder, Sheryl C; Middle, Christina M; Tremaine, Mary T; Jury, Thomas P; Delannay, Xavier; Slater, Steven C

2006-05-24

141

Creating the Course: A Limited Look into Human Progress & the Environment  

Microsoft Academic Search

Welcome to this class for the semester, located somewhere inside of the intersection of history, technology, the environment, and pedagogy. Through units on urban development and human advances in technology\\/policy, we will look at how humanity’s interactions with the environment have changed over time. I have also done my best to give you control over your own learning process in

Christopher Marra

2010-01-01

142

Blocks of Limited Haplotype Diversity Revealed by High-Resolution Scanning of Human Chromosome 21  

Microsoft Academic Search

Global patterns of human DNA sequence variation (haplotypes) defined by common single nucleotide polymorphisms (SNPs) have important implications for identifying disease associations and human traits. We have used high-density oligonucleotide arrays, in combination with somatic cell genetics, to identify a large fraction of all common human chromosome 21 SNPs and to directly observe the haplotype structure defined by these SNPs.

Nila Patil; Anthony J. Berno; David A. Hinds; Wade A. Barrett; Jigna M. Doshi; Coleen R. Hacker; Curtis R. Kautzer; Danny H. Lee; Claire Marjoribanks; David P. McDonough; Bich T. N. Nguyen; Michael C. Norris; John B. Sheehan; Naiping Shen; David Stern; Renee P. Stokowski; Daryl J. Thomas; Mark O. Trulson; Kanan R. Vyas; Kelly A. Frazer; Stephen P. A. Fodor; David R. Cox

2001-01-01

143

Study of hepatitis C virus entry in genetically humanized mice.  

PubMed

Approximately 2% of the world's population is chronically infected with hepatitis C virus (HCV). Chronic hepatitis C can culminate in end stage liver disease and liver cancer if the infection is untreated. Current therapy is only partially effective and a vaccine for HCV does not exist. Since the discovery of HCV as the etiologic agent causing hepatitis C several experimental tools have been developed which have improved our understanding of the viral life cycle and the interaction of HCV with human cells. However, it remains challenging to study HCV infection in its native liver environment given its narrow species tropism, limited to humans and chimpanzees. Mice can be rendered susceptible to HCV infection by transplanting human hepatocytes into immunocompromized liver injury strains. Such human liver chimeric mice are useful as a challenge model for human hepatotropic pathogens but their utility is hampered by their inability to mount functional immune responses and practical aspects including high costs, low throughput, and donor-to-donor variability. The barriers that restrict HCV species tropism are incompletely understood. We have previously shown that expression of human CD81 and human OCLN is required for HCV uptake into mouse cells. This led to the construction of a genetically humanized mouse model for HCV infection. Here, we provide a detailed protocol for the generation of these animals and highlight some of its applications for studying HCV biology and preclinical testing of drug and vaccine candidates. PMID:22687621

Dorner, Marcus; Rice, Charles M; Ploss, Alexander

2012-06-08

144

Limitations and Applications of ICA in Facial sEMG and Hand Gesture sEMG for Human Computer Interaction  

Microsoft Academic Search

In the recent past, there has been an increasing trend of using Blind Signal Separation (BSS) or Independent Component Analysis (ICA) algorithm for bio medical data, especially in prosthesis and Human Computer Interaction (HCI) applications. This paper reviews the concept of BSS and demonstrates its usefulness and limitations in the context of surface electromyogram related to hand movements and vowel

Ganesh R. Naik; Dinesh Kant Kumar; Sridhar Poosapadi Arjunan; Hans Weghorn; Marimuthu Palaniswami

2007-01-01

145

Flow motifs reveal limitations of the static framework to represent human interactions.  

PubMed

Networks are commonly used to define underlying interaction structures where infections, information, or other quantities may spread. Although the standard approach has been to aggregate all links into a static structure, some studies have shown that the time order in which the links are established may alter the dynamics of spreading. In this paper, we study the impact of the time ordering in the limits of flow on various empirical temporal networks. By using a random walk dynamics, we estimate the flow on links and convert the original undirected network (temporal and static) into a directed flow network. We then introduce the concept of flow motifs and quantify the divergence in the representativity of motifs when using the temporal and static frameworks. We find that the regularity of contacts and persistence of vertices (common in email communication and face-to-face interactions) result on little differences in the limits of flow for both frameworks. On the other hand, in the case of communication within a dating site and of a sexual network, the flow between vertices changes significantly in the temporal framework such that the static approximation poorly represents the structure of contacts. We have also observed that cliques with 3 and 4 vertices containing only low-flow links are more represented than the same cliques with all high-flow links. The representativity of these low-flow cliques is higher in the temporal framework. Our results suggest that the flow between vertices connected in cliques depend on the topological context in which they are placed and in the time sequence in which the links are established. The structure of the clique alone does not completely characterize the potential of flow between the vertices. PMID:23679480

Rocha, Luis E C; Blondel, Vincent D

2013-04-22

146

Subject indicators to present the nature and limit of environmental studies in US graduate schools  

Microsoft Academic Search

Summary The purpose of this paper is to examine subjects to show the nature and limit of interdisciplinary communication in existing environmental programmes in US graduate schools. Ultimately, this analysis may provide more effective communication with the general public. Following comparative historical reviews of both the sciences and the human activity for environmental protection, and a content analysis of empirical

H. S. Kim; James P. Dixon

1993-01-01

147

Evidence that diffusion limitation determines oxygen uptake kinetics during exercise in humans.  

PubMed Central

To determine the role of arterial O2 content on the mechanism of muscle O2 utilization, we studied the effect of 2, 11, and 20% carboxyhemoglobin (COHb) on O2 uptake (VO2), and CO2 output (VCO2) kinetics in response to 6 min of constant moderate- and heavy-intensity cycle exercise in 10 subjects. Increased COHb did not affect resting heart rate, VO2 or VCO2. Also, the COHb did not affect the asymptotic VO2 in response to exercise. However, VO2 and VCO2 kinetics were affected differently. The time constant (TC) of VO2 significantly increased with increased COHb for both moderate and heavy work intensities. VO2 TC was positively correlated with blood lactate. In contrast, VCO2 TC was negatively correlated with increased COHb for the moderate but unchanged for the heavy work intensity. The gas exchange ratio reflected a smaller increase in CO2 stores and faster VCO2 kinetics relative to VO2 with increased COHb. These changes can be explained by compensatory cardiac output (heart rate) increase in response to reduced arterial O2 content. The selective slowing of VO2 kinetics, with decreased blood O2 content and increased cardiac output, suggests that O2 is diffusion limited at the levels of exercise studied.

Koike, A; Wasserman, K; McKenzie, D K; Zanconato, S; Weiler-Ravell, D

1990-01-01

148

Community Engagement in Observational Human Exposure Studies  

EPA Science Inventory

Although observational human exposure studies do not deliberately expose participants to chemicals or environmental conditions, merely involving people as research participants and conducting research inside homes raises ethical issues. Community engagement offers a promising st...

149

Study of human bone tumor slice by SRXRF microprobe  

NASA Astrophysics Data System (ADS)

The SRXRF microprobe at the BSRF is described. The minimum detection limits (MDLs) of trace elements were measured to determine the capability for biological sample analysis. The changes of the trace elements and their ratios in the normal and tumor parts of a human osteosarcoma tissue were investigated. It was found that our results were in agreement with those of other analytical methods, such as spectrophotometric analysis, NAA and PIXE as well as an early clinic study of serum.

Huang, Y. Y.; Lu, J. X.; He, R. G.; Zhao, L. M.; Wang, Z. G.; He, W.; Zhang, Y. X.

2001-07-01

150

Human Studies on Polyglycerol Polyricinoleate (PGPR)  

Microsoft Academic Search

A series of toxicology studies was conducted in the 1950s and 1960s to investigate the toxicity of ADMUL WOL, a brand of polyglcerol polyricinoleate (PGPR). A component of these investigations included studies in human subjects. During 1964 and 1965, PGPR was fed to 19 human volunteers whose diet contained constant levels of fat and protein. Up to 10g\\/day PGPR was

R. Wilson; M. Smith

1998-01-01

151

Prevention and treatment of human immunodeficiency virus/acquired immunodeficiency syndrome in resource-limited settings.  

PubMed Central

Strategies for confronting the epidemic of human immunodeficiency virus/acquired immunodeficiency syndrome (HIV/AIDS) have included a range of different approaches that focus on prevention and treatment. However, debate persists over what levels of emphasis are appropriate for the different components of the global response. This paper presents an overview of this debate and briefly summarizes the evidence on a range of interventions designed to prevent the spread of HIV infection, paying particular attention to voluntary counselling and testing, treatment for sexually transmitted infections and prevention of mother-to-child transmission. We also review the experience with antiretroviral therapy to date in terms of response rates and survival rates, adherence, drug resistance, behavioural change and epidemiological impact. Although various studies have identified strategies with proven effectiveness in reducing the risks of HIV infection and AIDS mortality, considerable uncertainties remain. Successful integration of treatment and prevention of HIV/AIDS will require a balanced approach and rigorous monitoring of the impact of programmes in terms of both individual and population outcomes.

Hogan, Daniel R.; Salomon, Joshua A.

2005-01-01

152

Human neutrophil elastase modulates platelet function by limited proteolysis of membrane glycoproteins.  

PubMed Central

During blood coagulation human polymorphonuclear leukocytes release elastase in amounts that can exceed 100 nmol/liter. We therefore studied the effect of elastase on platelet structure and function. Physiologic concentrations of elastase specifically inhibited thrombin-induced platelet aggregation and ristocetin-induced agglutination of washed platelets in a time- and dose-dependent manner. This was associated with a decrease in the number of high affinity thrombin binding sites on the platelet surface (analysis by "Ligand" program) from 31 per platelet to 12 per platelet (P less than 0.05). As analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, treatment of 3H-labeled platelets with elastase resulted in a decrease in the percent glycoprotein at 130,000-150,000 Mr = and an increase in the percent protein at Mr = 102,000. The supernatant from elastase-treated platelets contained a Mr = 88,000 glycoprotein not found in the supernatant from untreated platelets. Immunoprecipitation studies with monoclonal antiglycoprotein Ib demonstrated that treatment of whole platelets with physiologic concentrations of elastase resulted in proteolytic cleavage of glycoprotein Ib. Elastase treatment of glycoprotein immunoisolated with monoclonal antiglycoprotein Ib antibody resulted in formation of a glycopeptide with the same electrophoretic mobility as the Mr = 102,000 membrane-related glycopeptide. In contrast, analysis by Western blot technique using antiglycoprotein IIb and IIIa antibodies demonstrated that elastase did not degrade glycoproteins IIb or IIIa. We conclude that elastase inhibition of thrombin-induced platelet stimulation is accompanied by (a) a reduction in the number of thrombin binding sites per platelet and (b) proteolysis of glycoprotein Ib. Images

Brower, M S; Levin, R I; Garry, K

1985-01-01

153

The limits of adaptation: humans and the predator-prey arms race.  

PubMed

In the history of life, species have adapted to their consumers by evolving a wide variety of defenses. By contrast, animal species harvested in the wild by humans have not adapted structurally. Nonhuman predators have high failure rates at one or more stages of an attack, indicating that victim species have spatial refuges or phenotypic defenses that permit further functional improvement. A new compilation confirms that species in the wild cannot achieve immunity from human predation with structural defenses. The only remaining options are to become undesirable or to live in or escape to places where harvesting by people is curtailed. Escalation between prey defenses and predators' weapons may be restricted under human dominance to interactions involving those low-level predators that have benefited from human overexploitation of top consumers. PMID:22759280

Vermeij, Geerat J

2012-03-03

154

Studies of Human Mutation Rates. Progress Report.  

National Technical Information Service (NTIS)

Progress is reported on several areas of study relating to human mutation rates. Efforts to study mutation at the DNA level dealt mainly with the development of probes to be employed in the program. Also reported on were genetic follow-up studies at the R...

J. V. Neel

1988-01-01

155

Defining Limits of Treatment with Humanized Neutralizing Monoclonal Antibody for West Nile Virus Neurological Infection in a Hamster Model?  

PubMed Central

A potent anti-West Nile virus (anti-WNV)-neutralizing humanized monoclonal antibody, hE16, was previously shown to improve the survival of WNV-infected hamsters when it was administered intraperitoneally (i.p.), even after the virus had infected neurons in the brain. In this study, we evaluated the therapeutic limit of hE16 for the treatment of WNV infection in hamsters by comparing single-dose peripheral (i.p.) therapy with direct administration into the pons through a convection-enhanced delivery (CED) system. At day 5 after infection, treatments with hE16 by the peripheral and the CED routes were equally effective at reducing morbidity and mortality. In contrast, at day 6 only the treatment by the CED route protected the hamsters from lethal infection. These experiments suggest that hE16 can directly control WNV infection in the central nervous system. In support of this, hE16 administered i.p. was detected in a time-dependent manner in the serum, cerebrospinal fluid (CSF), cerebral cortex, brain stem, and spinal cord in CSF. A linear relationship between the hE16 dose and the concentration in serum was observed, and maximal therapeutic activity occurred at doses of 0.32 mg/kg of body weight or higher, which produced serum hE16 concentrations of 1.3 ?g/ml or higher. Overall, these data suggest that in hamsters hE16 can ameliorate neurological disease after significant viral replication has occurred, although there is a time window that limits therapeutic efficacy.

Morrey, John D.; Siddharthan, Venkatraman; Olsen, Aaron L.; Wang, Hong; Julander, Justin G.; Hall, Jeffery O.; Li, Hua; Nordstrom, Jeffrey L.; Koenig, Scott; Johnson, Syd; Diamond, Michael S.

2007-01-01

156

Limited infection upon human exposure to a recombinant raccoon pox vaccine vector.  

PubMed

A laboratory accident resulted in human exposure to a recombinant raccoon poxvirus (RCN) developed as a vaccine vector for antigens of Yersinia pestis for protection of wild rodents (and other animals) against plague. Within 9 days, the patient developed a small blister that healed within 4 weeks. Raccoon poxvirus was cultured from the lesion, and the patient developed antibody to plague antigen (F1) and RCN. This is the first documented case of human exposure to RCN. PMID:15246608

Rocke, Tonie E; Dein, F Joshua; Fuchsberger, Martina; Fox, Barry C; Stinchcomb, Dan T; Osorio, Jorge E

2004-07-29

157

The Limits of the human security agenda: the case of Canada's response to the Timor crisis  

Microsoft Academic Search

Enthusiasts of human security argue that what is needed in the post?Cold?War period is a foreign policy agenda that is more ‘people?centred’ than the state?centred focus of security policy during the Cold War period. Among the most enthusiastic proponents of the human security paradigm in the 1990s was the Canadian government, which, in partnership with a number of other like?minded

T. S. Hataley; Kim Richard Nossal

2004-01-01

158

Studies of human mutation rates  

SciTech Connect

November 1989, marked the beginning of a new three-year cycle of DOE grant support, in connection with which the program underwent a major reorganization. This document presents the progress on the three objectives of the present program which are: to isolate by the technique of two-dimensional polyacrylamide gel electrophoresis (2-D PAGE), proteins of special interest because of the relative mutability of the corresponding gene, establish the identity of the protein, and, for selected proteins, move to a characterization of the corresponding gene; to develop a more efficient approach, based on 2-D PAGE, for the detection of variants in DNA, with special reference to the identification of mutations in the parents of the individual whose DNA is being examined; and, to continue an effective interface with the genetic studies on the children of atomic bomb survivors in Japan, with reference to both the planning and implementation of new studies at the molecular level.

Neel, J.V.

1990-01-01

159

Studies of human mutation rates  

SciTech Connect

The three objectives of the program are: To isolate by the technique of two-dimensional polyacrylamide gel electrophoresis (2-D PAGE), proteins of special interest because of the relative mutability of the corresponding gene, establish the identity of the protein, and, for selected proteins, move to a characterization of the corresponding gene; To develop a more efficient approach, based on 2-D PAGE, for the detection of variants in DNA, with special reference to the identification of a variant in a child not present in either parent of the child (i.e., a mutation); and, To continue an effective interface with the genetic studies on the children of atomic bomb survivors in Japan, with reference to both the planning and implementation of new studies at the molecular level. For administrative purposes, the program is subdivided into four sections, each under the direction of one of the four co-PIs; the progress during the past year will be summarized in accordance with this sectional structure. 1 tab.

Neel, J.V.

1991-07-15

160

A new Cosmological Study Approach with a Volume Limited X-ray Cluster Sample  

NASA Astrophysics Data System (ADS)

The application of galaxy clusters in constraining cosmological models is currently mostly limited by our uncertain knowledge of scaling relations of easy observables and cluster mass. Most of the scaling relation studies are based on X-ray flux limited samples. Here we propose to take a new approach to study galaxy cluster properties in a volume-limited sample. From the comparison of flux and volume-limited samples we would be able to determine the intrinsic scatter of scaling relations in an unambiguous way, providing an important advance in cluster cosmology studies. Apart from the cosmological application, the volume-limited survey of nearby clusters will also provide a great benchmark sample for all aspects of characterizing the properties of the cluster population.

Boehringer, Hans

2010-10-01

161

Red, Yellow, Blue: A Primary Study of the Strengths, Limitations and Challenges of Arts Magnet Schools.  

ERIC Educational Resources Information Center

|This primary, exploratory study combines the limited literature on arts magnet schools with the writings of arts activists and the narratives of several arts magnet school administrators in an attempt to understand arts magnet schools better. The paper illuminates some of the strengths of arts magnet schools as well as some of the limitations and…

Halquist, Don

162

HUMEX, a study on the survivability and adaptation of humans to long- duration exploratory missions  

Microsoft Academic Search

ESA has recently initiated a study of the human responses, limits and needs with regard to the stress environments of interplanetary and planetary missions. Emphasis was laid on human health and performance care as well as Advanced Life Support Developments including Bioregenerative Life Support Systems and environmental monitoring. The overall study goals were as follows: (i) to define reference scenarios

G. Horneck

2002-01-01

163

Suppression of plasma virus load below the detection limit of a human immunodeficiency virus kit is associated with longer virologic response than suppression below the limit of quantitation.  

PubMed

Suppression of human immunodeficiency virus type 1 plasma virus load (PVL) to <20 copies/mL is associated with a longer virologic response after initiation of antiretroviral therapy. The relationship between duration of virologic response and PVL nadir according to a less sensitive assay was explored. When compared with subjects with a PVL nadir >500 copies/mL, the relative risks of PVL rising above 1000 copies/mL for participants in the INCAS trial and the British Columbia Drug Treatment Program with a PVL nadir below the limit of detection (LOD) were 0.04 (95% confidence interval [CI], 0.02-0.09) and 0.06 (95% CI, 0.03-0.12), respectively. The corresponding relative risks for persons with a detectable but not quantifiable PVL nadir were 0.25 (95% CI, 0.13-0.50) and 0.54 (95% CI, 0.25-1.19). The relative risks of virologic failure associated with a PVL nadir detectable but not quantifiable and a PVL nadir below the LOD were statistically different (P<.0001) in both data sets. PMID:10479170

Raboud, J M; Rae, S; Hogg, R S; Yip, B; Sherlock, C H; Harrigan, P R; O'Shaughnessy, M V; Montaner, J S

1999-10-01

164

Testing paradigm for prediction of development-limiting barriers and human drug toxicity  

Microsoft Academic Search

The financial investment grows exponentially as a new chemical entity advances through each stage of discovery and development. The opportunity exists for the modern toxicologist to significantly impact expenditures by the early prediction of potential toxicity\\/side effect barriers to development by aggressive evaluation of development-limiting liabilities early in drug discovery. Improved efficiency in pharmaceutical research and development lies both in

V. G. Sasseville; V. J. Kadambi; P. Bouchard; F. W. Lee; S. K. Balani; G. T. Miwa; P. F. Smith; C. L. Alden

2004-01-01

165

Limiting the impact of light pollution on human health, environment and stellar visibility  

Microsoft Academic Search

Light pollution is one of the most rapidly increasing types of environmental degradation. Its levels have been growing exponentially over the natural nocturnal lighting levels provided by starlight and moonlight. To limit this pollution several effective practices have been defined: the use of shielding on lighting fixture to prevent direct upward light, particularly at low angles above the horizon; no

Fabio Falchi; Pierantonio Cinzano; Christopher D. Elvidge; David M. Keith; Abraham Haim

2011-01-01

166

Prevention and treatment of human immunodeficiency virus\\/acquired immunodeficiency syndrome in resource- limited settings  

Microsoft Academic Search

Strategies for confronting the epidemic of human immunodeficiency virus\\/acquired immunodeficiency syndrome (HIV\\/AIDS) have included a range of different approaches that focus on prevention and treatment. However, debate persists over what levels of emphasis are appropriate for the different components of the global response. This paper presents an overview of this debate and briefly summarizes the evidence on a range of

Daniel R. Hogan; Joshua A. Salomon

2005-01-01

167

Variation in human brains may facilitate evolutionary change toward a limited range of phenotypes.  

PubMed

Individual variation is the foundation for evolutionary change, but little is known about the nature of normal variation between brains. Phylogenetic variation across mammalian brains is characterized by high intercorrelations in brain region volumes, distinct allometric scaling for each brain region and the relative independence of olfactory and limbic structure volumes from the rest of the brain. Previous work examining brain variation in individuals of some domesticated species showed that these three features of phylogenetic variation were mirrored in individual variation. We extend this analysis to the human brain and 10 of its subdivisions (e.g., isocortex and hippocampus) by using magnetic resonance imaging scans of 90 human brains ranging between 16 and 25 years of age. Human brain variation resembles both the individual variation seen in other species and variation observed across mammalian species, i.e., the relative differences in the slopes of each brain region compared to medulla size within humans and between mammals are concordant, and limbic structures scale with relative independence from other brain regions. This nonrandom pattern of variation suggests that developmental programs channel the variation available for selection. PMID:23363667

Charvet, Christine J; Darlington, Richard B; Finlay, Barbara L

2013-01-25

168

Transferring human resource practices from the United Kingdom to China: the limits and potential for convergence  

Microsoft Academic Search

Substantial effort has been devoted to exploring the transfer of human resource management practices within multinational companies. Particular attention has been paid to countries with ‘strong’ HRM traditions, to transfers between economically developed countries and to firms in the manufacturing sector. This paper addresses the transfer of a British-owned retail firm's HRM practices from the United Kingdom to the People's

Jos Gamble

2003-01-01

169

Repression of mammary adipogenesis by genistein limits mammosphere formation of human MCF-7 cells  

Technology Transfer Automated Retrieval System (TEKTRAN)

Mammary adipose tissue may contribute to breast cancer development and progression by altering neighboring epithelial cell behavior and phenotype through paracrine signaling. Dietary exposure to soy foods is associated with lower mammary tumor risk and reduced body weight and adiposity in humans and...

170

PUSH(ing) Limits: Using Fiction in the Classroom for Human Behavior and the Social Environment  

ERIC Educational Resources Information Center

|The use of fiction and autobiography in social science course work has been shown to enhance students' learning experience. Using the novel PUSH, by Sapphire, we designed a curriculum supplement for the social work course, human behavior and the social environment (HBSE) that encourages students to integrate course content in an innovative way…

Mendoza, Natasha S.; Bonta, Kimberly; Horn, Philip; Moore, Erin; Gibson, Allison; Simmons, David

2012-01-01

171

Non-Human Nature and the Ecosystem Approach: The Limits of Anthropocentrism in Great Lakes Management.  

ERIC Educational Resources Information Center

The ecosystem approach is a management philosophy in which humans participate in the natural world, not dominate it. Discusses this concept with respect to the Great Lakes context, the anthropocentric argument, sustainable development, and integrating economy and environment. (Contains 52 references.) (MDH)

Bell, Anne

1994-01-01

172

Reasonable Limits and Exemptions: Victoria's Human Rights Charter and its Implications for Young People  

ERIC Educational Resources Information Center

|Many people had great expectations of the Victorian Charter of Human Rights and Responsibilities when it came into effect in January 2008. However, Judith Bessant asks whether the provision for seeking exemptions from the charter has undermined its capacity to effectively counter age-based discrimination and, paradoxically, permitted practices…

Bessant, Judith

2009-01-01

173

Experimental study of plasma properties in the shadow of the T--10 mushroom limiter  

SciTech Connect

The plasma properties in the shadow of a mushroom-shaped limiter installed in a lower port of the tokamak have been studied. A study of the asymmetry of the plasma streams on the ion and electron sides of the limiter leads to the conclusion that there are two mechanisms for the occurrence of the asymmetry: the toroidal rotation of the plasma and a predominant escape of plasma to the wall through the outer part of the torus. The asymmetry observed in the plasma floating potentials near the limiter leads to the flow of a current close to the Spitzer value j/sub S/ through the limiter. With increasing plasma density, the plasma density in the channels of the limiter increases, and the temperature of this plasma decreases, so the loss of charged particles to the limiter depends only weakly on the average density. This circumstance is related to the degradation of the plasma confinement with decreasing density. The total flux of charged particles to the limiter is comparable to the flux of these particles out of the plasma column. The plasma stream into the channels is approximately ambipolar, and the power levels drawn by the neutralization plate are on the order of 10j/sub S/T/sub e//e. The behavior of the neutral gas pressure in the volume near the limiter as a function of the plasma streams into the channels is nonlinear. The maximum pressure is 3x10/sup -2/ torr.

Alferov, A.A.; Vershkov, V.A.; Grashin, S.A.; Chankin, A.V.

1988-04-01

174

Therapeutic targeting of epidermal growth factor receptor in human cancer: successes and limitations  

PubMed Central

Epidermal growth fac tor receptor (EGFR) is one of the most commonly altered genes in human cancer by way of over-expression, amplification, and mutation. Targeted inhibition of EGFR activity suppresses signal transduction pathways which control tumor cell growth, proliferation, and resistance to apoptosis. Small molecule tyrosine kinase inhibitors and monoclonal antibodies are among the most common EGFR-targeting agents and have been used clinically for treating various malignancies. This review discusses the successes and challenges of targeting EGFR in human cancer. The genetic alterations of EGFR tend to occur more often in some solid tumors than others, as do the mechanisms of resistance to targeted inhibition. The clinical and basic science experiences with these agents thus far have important implications for the future of therapeutic targeting of EGFR.

Wykosky, Jill; Fenton, Tim; Furnari, Frank; Cavenee, Webster K.

2012-01-01

175

On the generality and limits of abstraction in rats and humans  

Microsoft Academic Search

In this review, we address the question, central to cognition, of whether nonhuman animals such as rats are capable of extracting\\u000a and extending information from a given learning situation to a new learning situation without generalizing through a physical\\u000a dimension of the stimuli. This capacity underlies abstraction, which is a hallmark of human cognition and necessary for complex\\u000a information processing

Gonzalo P. UrcelayRalph; Ralph R. Miller

2010-01-01

176

Monoamine oxidase: radiotracer development and human studies.  

National Technical Information Service (NTIS)

PET is uniquely capable of providing information on biochemical transformations in the living human body. Although most of the studies of monoamine oxidase (MAO) have focused on measurements in the brain, the role of peripheral MAO as a phase 1 enzyme for...

Fowler Logan Volkow Wang MacGregor Ding

2000-01-01

177

Reporting Participants in Research Studies to Child Protective Services: Limited Risk to Attrition  

Microsoft Academic Search

This study examines the impact of Child Protective Services (CPS) reports made by research study staff on participant retention and discusses human subjects protocols that may minimize either the need to make such reports or the negative impact of reporting on participants and on participant retention. Among 1, 354 primary caregiver-child pairs in the Longitudinal Studies of Child Abuse and

Elizabeth Dawes Knight; Jamie B. Smith; Howard Dubowitz; Alan J. Litrownik; Jonathan B. Kotch; Diana English; Mark D. Everson; Desmond K. Runyan

2006-01-01

178

Genomic approaches to studying the human microbiota.  

PubMed

The human body is colonized by a vast array of microbes, which form communities of bacteria, viruses and microbial eukaryotes that are specific to each anatomical environment. Every community must be studied as a whole because many organisms have never been cultured independently, and this poses formidable challenges. The advent of next-generation DNA sequencing has allowed more sophisticated analysis and sampling of these complex systems by culture-independent methods. These methods are revealing differences in community structure between anatomical sites, between individuals, and between healthy and diseased states, and are transforming our view of human biology. PMID:22972298

Weinstock, George M

2012-09-13

179

The Human Studies Database Project: Federating Human Studies Design Data Using the Ontology of Clinical Research  

PubMed Central

Human studies, encompassing interventional and observational studies, are the most important source of evidence for advancing our understanding of health, disease, and treatment options. To promote discovery, the design and results of these studies should be made machine-readable for large-scale data mining, synthesis, and re-analysis. The Human Studies Database Project aims to define and implement an informatics infrastructure for institutions to share the design of their human studies. We have developed the Ontology of Clinical Research (OCRe) to model study features such as design type, interventions, and outcomes to support scientific query and analysis. We are using OCRe as the reference semantics for federated data sharing of human studies over caGrid, and are piloting this implementation with several Clinical and Translational Science Award (CTSA) institutions.

Sim, Ida; Carini, Simona; Tu, Samson; Wynden, Rob; Pollock, Brad H.; Mollah, Shamim A.; Gabriel, Davera; Hagler, Herbert K.; Scheuermann, Richard H.; Lehmann, Harold P.; Wittkowski, Knut M.; Nahm, Meredith; Bakken, Suzanne

2010-01-01

180

Host limits to accurate human growth hormone production in multiple plant systems.  

PubMed

Human growth hormone (hGH) is not only a valuable recombinant therapeutic protein for hormone deficiency indications, but is also an extensively characterized molecule both from recombinant bacterial systems and as circulating in humans. We describe the characterization of hGH produced in three different plant systems: tobacco cell culture, soy seed, and maize seed. The data indicate highest production in the maize seed system, with continued productivity over multiple generations, and when bred to a new host genotype for improved productivity. Purification indicated significant material of the correct structure from both plant cell culture and maize seed, with maize seed also showing correct activity relative to that produced by Escherichia coli. However, all systems showed some proteolyzed hGH, with data from gel electrophoresis, mass spectrometry, and peptide mapping localizing to a region of the protein also prone to cleavage in some other systems. Together, the data indicate the dependence of recombinant protein accumulation on posttranslational processes in different host systems. PMID:15696512

Russell, Douglas A; Spatola, Lori A; Dian, Titik; Paradkar, Vikram M; Dufield, Dawn R; Carroll, James A; Schlittler, Michael R

2005-03-30

181

Features and limitations of digital human models--a new German guideline.  

PubMed

In 2008 the Association of German Engineers (VDI) published the first part of the VDI 4499 guideline for methods and tools for the digital factory. Part 1 of this guideline deals with the fundamentals of the system and will be expanded by the addition of further parts on specific topics within the digital factory. Soon to be published is Part 4 which covers human models as tools of the digital factory. It describes the state of the art of current digital human models with regards to the methods and procedures implemented in German speaking countries. The structure of this part of the guideline is based on the different sections of engineering mechanics and outlines the opportunities for ergonomic assessments and the evaluation of work systems. During the writing of the guideline, the restrictions of the existing procedures also became evident thus showing the requirement for further development of such procedures. This is illustrated in this paper using examples from commercial software systems. PMID:22317050

Zülch, Gert

2012-01-01

182

Binding of transmembrane mucins to galectin-3 limits herpesvirus 1 infection of human corneal keratinocytes.  

PubMed

Epithelial cells lining mucosal surfaces impose multiple barriers to viral infection. At the ocular surface, the carbohydrate-binding protein galectin-3 maintains barrier function by cross-linking transmembrane mucins on the apical glycocalyx. Despite these defense mechanisms, many viruses have evolved to exploit fundamental cellular processes on host cells. Here, we use affinity assays to show that herpes simplex virus type 1 (HSV-1), but not HSV-2, binds human galectin-3. Knockdown of galectin-3 in human corneal keratinocytes by small interfering RNA significantly impaired HSV-1 infection, but not expression of nectin-1, indicating that galectin-3 is a herpesvirus entry mediator. Interestingly, exposure of epithelial cell cultures to transmembrane mucin isolates decreased viral infectivity. Moreover, HSV-1 failed to elute the biological counterreceptor MUC16 from galectin-3 affinity columns, suggesting that association of transmembrane mucins to galectin-3 provides protection against viral infection. Together, these results indicate that HSV-1 exploits galectin-3 to enhance virus attachment to host cells and support a protective role for transmembrane mucins under physiological conditions by masking viral entry mediators on the epithelial glycocalyx. PMID:23487460

Woodward, A M; Mauris, J; Argüeso, P

2013-03-13

183

A PILOT STUDY TO COMPARE MICROBIAL AND CHEMICAL INDICATORS OF HUMAN FECAL CONTAMINATION IN WATER  

EPA Science Inventory

Limitations exist in applying traditional microbial methods for the detection of human fecal contamination of water. A pilot study was undertaken to compare the microbial and chemical indicators of human fecal contamination of water. Sixty-four water samples were collected in O...

184

Combined spectrophotometry and tensile measurements of human connective tissues: potentials and limitations.  

PubMed

Strain-dependent transmission data of nine iliotibial tract specimens are determined using a custom-built optical setup with a halogen light source and an industrial norm material testing machine. Polarized light microscopy and hematoxylin-eosin staining indicated that lateral contraction of collagen structures is responsible for total intensity variations during a 20-cycle preconditioning and a 5-cycle tensile test. Tensile force progress is opposite to total transmission progress. Due to dehydration, wavelength-specific radiation intensity shifting is determined during the test, primarily noticeable in a water absorption band between 1400 and 1500 nm. The results show the capability of integrating spectrophotometry technology into biomechanics for determining structural alterations of human collagen due to applied strain. Being more sensitive to drying, spectrophotometry may likely serve as a quality control in stress-strain testing of biological structures. PMID:23797894

Ernstberger, Markus; Sichting, Freddy; Baselt, Tobias; Hartmann, Peter; Aust, Gabriela; Hammer, Niels

2013-06-01

185

Safety, identity and consent: a limited defense of reproductive human cloning.  

PubMed

Some opponents of reproductive human cloning have argued that, because of its experimental nature, any attempt to create a child by way of cloning would risk serious birth defects or genetic abnormalities and would therefore be immoral. Some versions of this argument appeal to the consent of the person to be conceived in this way. In particular, they assume that if an experimental reproductive technology has not yet been shown to be safe, then, before we use it, we are morally obligated to get either the actual consent or the presumed consent of the person to be conceived. In this article, I attempt to explain the appeal of such consent-based arguments as deriving from a mistaken view of personal identity. I then argue that since this view is false, such arguments are unsound. Finally, I argue that even if reproductive cloning is unsafe, it may still be morally permissible in some circumstances. PMID:17039631

Lane, Robert

2006-06-01

186

The utility and limitations of glycosylated human CD133 epitopes in defining cancer stem cells  

PubMed Central

Human CD133 (human prominin-1), a five transmembrane domain glycoprotein, was originally identified as a cell surface antigen present on CD34+ hematopoietic stem cells. Although the biological function of CD133 is not well understood, antibodies to CD133 epitopes have been widely used to purify hematopoietic stem and progenitor cells. The cancer stem cell (CSC) hypothesis postulates that a rare population of tumor cells possessing increased capacities for self-renewal and tumor initiation is responsible for maintaining the growth of neoplastic tissue. The expression of the CD133 epitopes, AC133 and AC141, has been shown to define a subpopulation of brain tumor cells with significantly increased capacity for tumor initiation in xenograft models. Following the discovery of the AC133/AC141+ population of brain tumor stem cells, the AC133 and AC141 epitopes have been extensively used as markers for purifying CSCs in other solid tumors. There are, however, several issues associated with the use of the AC133 and AC141 CD133 epitopes as markers for CSCs. The antibodies routinely used for purification of AC133 and AC141-positive cells target poorly characterized glycosylated epitopes of uncertain specificity. Discordant expression of the AC133 and AC141 epitopes has been observed, and the epitopes can be absent despite the presence of CD133 protein. In addition, CD133 expression has recently been shown to be modulated by oxygen levels. These factors, in combination with the uncertain biological role of CD133, suggest that the use of CD133 expression as a marker for CSCs should be critically evaluated in each new experimental system and highlight the need for additional CSC surface markers that are directly involved in maintaining CSC properties.

Bidlingmaier, Scott; Zhu, Xiaodong; Liu, Bin

2008-01-01

187

Antecedent Avian Immunity Limits Tangential Transmission of West Nile Virus to Humans  

PubMed Central

Background West Nile virus (WNV) is a mosquito-borne flavivirus maintained and amplified among birds and tangentially transmitted to humans and horses which may develop terminal neuroinvasive disease. Outbreaks typically have a three-year pattern of silent introduction, rapid amplification and subsidence, followed by intermittent recrudescence. Our hypothesis that amplification to outbreak levels is contingent upon antecedent seroprevalence within maintenance host populations was tested by tracking WNV transmission in Los Angeles, California from 2003 through 2011. Methods Prevalence of antibodies against WNV was monitored weekly in House Finches and House Sparrows. Tangential or spillover transmission was measured by seroconversions in sentinel chickens and by the number of West Nile neuroinvasive disease (WNND) cases reported to the Los Angeles County Department of Public Health. Results Elevated seroprevalence in these avian populations was associated with the subsidence of outbreaks and in the antecedent dampening of amplification during succeeding years. Dilution of seroprevalence by recruitment resulted in the progressive loss of herd immunity following the 2004 outbreak, leading to recrudescence during 2008 and 2011. WNV appeared to be a significant cause of death in these avian species, because the survivorship of antibody positive birds significantly exceeded that of antibody negative birds. Cross-correlation analysis showed that seroprevalence was negatively correlated prior to the onset of human cases and then positively correlated, peaking at 4–6 weeks after the onset of tangential transmission. Antecedent seroprevalence during winter (Jan – Mar) was negatively correlated with the number of WNND cases during the succeeding summer (Jul–Sep). Conclusions Herd immunity levels within after hatching year avian maintenance host populations <10% during the antecedent late winter and spring period were followed on three occasions by outbreaks of WNND cases during the succeeding summer. Because mosquitoes feed almost exclusively on these avian species, amplification was directly related to the availability of receptive non-immune hosts.

Kwan, Jennifer L.; Kluh, Susanne; Reisen, William K.

2012-01-01

188

2012 North Plains research field 12-200 limited irrigation corn production study  

Technology Transfer Automated Retrieval System (TEKTRAN)

2012 represented the third sequential year of research regarding the limited irrigation 12-200 corn production assessment study at the North Plains Research Field (NPRF) with the yield results being improved from that of the 2011 season but less than of the 2010 season. The study's purpose was to ev...

189

Limitations of the clonal agar assay for the assessment of primary human ovarian tumour biopsies.  

PubMed Central

114 biopsy specimens from 70 patients with ovarian carcinoma at all stages of disease were submitted for assessment of clonogenic capacity in agar. A highly significant correlation was found between agar clonogenicity and patient survival after biopsy. However, problems related to inherent tumour heterogeneity, quality of sample and tissue disaggregation indicate that this technique may have limited applicability in the routine assessment of patients. Only 41 biopsy specimens (36%) from 31 patients (44.3%) complied with the prerequisite criteria for agar clonogenic assessment, namely: (a) the confirmed presence of malignant cells in the biopsy, (b) the ability to prepare a single-cell suspension, and (c) adequate viable cell numbers for assay. Furthermore, although the dominant patterns of agar clonogenic growth could be identified and correlated with stage of disease, the heterogeneity in both initial clonogenic capacity and "self-renewal" capacity assessed by the ability of primary clones to propagate in liquid culture and reclone in agar was too inconsistent for the assay to be used as a prognostic index for the individual patient. Images Figure

Bertoncello, I.; Bradley, T. R.; Campbell, J. J.; Day, A. J.; McDonald, I. A.; McLeish, G. R.; Quinn, M. A.; Rome, R.; Hodgson, G. S.

1982-01-01

190

Human Immunodeficiency Virus and Leprosy Coinfection: Challenges in Resource-Limited Setups  

PubMed Central

Mycobacteria leprae(leprosy) and HIV coinfection are rare in Kenya. This is likely related to the low prevalence (1 per 10,000 of population) of leprosy. Because leprosy is no longer a public health challenge there is generally a low index of suspicion amongst clinicians for its diagnosis. Management of a HIV-1-leprosy-coinfected individual in a resource-constrained setting is challenging. Some of these challenges include difficulties in establishing a diagnosis of leprosy; the high pill burden of cotreatment with both antileprosy and antiretroviral drugs (ARVs); medications' side effects; drug interactions; scarcity of drug choices for both diseases. This challenge is more profound when managing a patient who requires second-line antiretroviral therapy (ART). We present an adult male patient coinfected with HIV and leprosy, who failed first-line antiretroviral therapy (ART) and required second-line treatment. Due to limited choices in antileprosy drugs available, the patient received monthly rifampicin and daily lopinavir-/ritonavir-based antileprosy and ART regimens, respectively. Six months into his cotreatment, he seemed to have adequate virological control. This case report highlights the challenges of managing such a patient.

Kwobah, Charles M.; Wools-Kaloustian, Kara K.; Gitau, Jane N.; Siika, Abraham M.

2012-01-01

191

Today's ``safe" radiofrequency (RF) exposure limits DON'T protect human health near transmitters!  

NASA Astrophysics Data System (ADS)

Maxwell's theory implies that electromagnetic (EM) radiation carries both energy and momentum. ``The momentum may have both linear and angular contributions; angular momentum [AM] has a spin part associated with polarization and an orbital part associated with spatial distribution. Any interaction between radiation and matter is inevitably accompanied by an exchange of momentum. This often has mechanical consequences ..."^2 Voluntary consensus standards [ANSI C95; NCRP; INCIRP] protect human health from most thermal [energy transfer] effects, but no standards yet exist to protect health against athermal [momentum transfer] effects, though laboratory transfer of spin AM was reported by 1935^3 and of orbital AM by 1992^2 for an optical vortex [tip of Poynting vector (PV) traces a helix about the beam axis]. In the far field of a dipole RF transmitter, radiation is linearly polarized (minimal spin AM) and locally approximated by a plane wave (zero orbital AM), but in the near field the orbital AM is non-zero [tip of PV traces an ellipse^4 in air] implying an athermal hazard [e.g., brain tumors in cellular phone users] against which no standard now in use anywhere in the world protects! ^2 L. Allen et al. Phys. Rev. A 45:8185-9(1992). ^3 R.A. Beth, Phys. Rev. 48:471(1935); 50:115-25 (1936). ^4 F. Landstorfer, Archiv für Elektronik und übertragungstechnik 26:189-96(1972) [in German].

Lundquist, Marjorie

2005-03-01

192

Studies on job satisfaction: a case study of Engineers India Limited  

Microsoft Academic Search

This paper has analysed the survey about Engineers India Limited, which is a Public Sector Undertaking in India. This paper shows employee’s satisfaction in working place not only reduces one’s temptation to switch over the Job but also makes organisation to flourish in return enabling it to recruit more. EIL hired employees consistently and that may be called only PSU

Geeta Kumari; Vittesh Bahuguna; Krishna M. Pandey

2012-01-01

193

Fundamental Limitation on Applicability of Statistical Methods to Study of Living Organisms and Other Complex Systems  

NASA Astrophysics Data System (ADS)

A living organism is a complex system whose state is characterized by extremely large number of variables that far exceeds the number of individual organisms that can be experimentally studied. Since the relations between these variables and even their identities are largely unknown, the applicability of statistical methods of inference to the outcome of experiments in biomedical sciences is severely limited. Far from being a purely theoretical issue, this explains the recently proposed "Truth Wears Off" effect and sets a fundamental limitation on the applicability of machine-like approaches to the study of living organisms.

Rabin, Yitzhak

2011-07-01

194

Community Environmental Factors Are Associated With Disability in Older Adults With Functional Limitations: The MOST Study  

PubMed Central

Background There is limited evidence supporting the hypothesized environment–disability link. The objectives of this study were to (a) identify the prevalence of community mobility barriers and transportation facilitators and (b) examine whether barriers and facilitators were associated with disability among older adults with functional limitations. Methods Four hundred and thirty-five participants aged 65+ years old with functional limitations were recruited from the Multicenter Osteoarthritis Study, a prospective study of community-dwelling adults with or at risk of developing symptomatic knee osteoarthritis. Presence of community barriers and facilitators was ascertained by the Home and Community Environment survey. Two domains of disability, (a) daily activity limitation (DAL) and (b) daily activity frequency (DAF), were assessed with the Late-Life Disability Instrument. Covariates included age, gender, education, race, comorbidity, body mass index, knee pain, and functional limitation. Multivariable logistic regression was used to examine adjusted associations of community factors with presence of DAL and DAF. Results Approximately one third of the participants lived in a community with high mobility barriers and low transportation facilitators. High mobility barriers was associated with greater odds of DAL (odds ratio [OR] = 2.0, 95% confidence interval [CI] 1.2–3.1) after adjusting for covariates, and high transportation facilitators was associated with lower odds of DAL (OR = 0.5, 95% CI 0.3–0.8) but not with DAF in adjusted models. Conclusion People with functional limitations who live in communities that were more restrictive felt more limited in doing daily activities but did not perform these daily activities any less frequently.

Jette, Alan M.; LaValley, Michael P.; Lewis, Cora E.; Torner, James C.; Nevitt, Michael C.; Felson, Dave T.

2010-01-01

195

40 CFR 26.1607 - Human Studies Review Board review of completed human research.  

Code of Federal Regulations, 2013 CFR

... 2013-07-01 2013-07-01 false Human Studies Review Board review of completed human research. 26.1607 Section 26.1607...PROTECTION AGENCY GENERAL PROTECTION OF HUMAN SUBJECTS Review of Proposed and...

2013-07-01

196

40 CFR 26.1606 - Human Studies Review Board review of proposed human research.  

Code of Federal Regulations, 2013 CFR

... 2013-07-01 2013-07-01 false Human Studies Review Board review of proposed human research. 26.1606 Section 26.1606...PROTECTION AGENCY GENERAL PROTECTION OF HUMAN SUBJECTS Review of Proposed and...

2013-07-01

197

Experimental methods to study human transplacental exposure to genotoxic agents  

Microsoft Academic Search

Human placenta differs more than any other organ between species. This is the primary reason to develop models utilizing human tissue to study placental functions. There are no major ethical restrictions using human placenta for scientific studies. Also, the size of human placenta enables a great number of different parameters to be studied in one placenta.The most important cell types

Kirsi Vähäkangas; Päivi Myllynen

2006-01-01

198

The Rational Choice Approach to Human Studies: A Reexamination  

Microsoft Academic Search

This article reexamines the rational choice or economic approach to human studies. Its adherents claim that its extension beyond its original domain to “all human behavior” can finally lead to integration of the human studies, especially social theory, and thus their elevation from what they see as a chaotic state. Specifically, they propose grounding human studies on the premise that

Milan Zafirovski

2003-01-01

199

Human studies on polyglycerol polyricinoleate (PGPR).  

PubMed

A series of toxicology studies was conducted in the 1950s and 1960s to investigate the toxicity of ADMUL WOL, a brand of polyglycerol polyricinoleate (PGPR). A component of these investigations included studies in human subjects. During 1964 and 1965, PGPR was fed to 19 human volunteers whose diet contained constant levels of fat and protein. Up to 10 g/day PGPR was fed to each volunteer in soups, cakes and toffee bars for 2 weeks. Pre-exposure normal values of biochemical parameters were established. Fat balance tests confirmed that digestion and absorption of PGPR took place. No consistent effect of PGPR on the various biochemical parameters was observed, nor had PGPR any toxic effect on liver and kidneys. The consumption of PGPR by humans produced no adverse effects. The quantities consumed, up to 10g/day, was equivalent to approximately 63 times the estimated maximum per capita mean daily intake by man of 2.64 mg kg body weight/day. It is therefore concluded from this study that the consumption of ADMUL WOL, a brand of PGPR, has no adverse effects in man. PMID:9737420

Wilson, R; Smith, M

200

Calcium hydroxide has limited effectiveness in eliminating bacteria from human root canal  

Microsoft Academic Search

Data sourcesSearches of Cochrane Central Register of Controlled Trials (CENTRAL), Medline, Embase, six thesis databases (Networked Digital Library of Theses and Dissertations, Proquest Digital Dissertations, OAIster, Index to Theses, Australian Digital Thesis program and Dissertation.com) and one conference report database (BIOSIS Previews) were undertaken. There were no language restrictions.Study selectionStudies were included in which participants had a noncontributory medical history,

Khaled A Balto

2007-01-01

201

Human studies of cannabinoids and medicinal cannabis.  

PubMed

Cannabis has been known as a medicine for several thousand years across many cultures. It reached a position of prominence within Western medicine in the nineteenth century but became mired in disrepute and legal controls early in the twentieth century. Despite unremitting world-wide suppression, recreational cannabis exploded into popular culture in the 1960s and has remained easily obtainable on the black market in most countries ever since. This ready availability has allowed many thousands of patients to rediscover the apparent power of the drug to alleviate symptoms of some of the most cruel and refractory diseases known to humankind. Pioneering clinical research in the last quarter of the twentieth century has given some support to these anecdotal reports, but the methodological challenges to human research involving a pariah drug are formidable. Studies have tended to be small, imperfectly controlled, and have often incorporated unsatisfactory synthetic cannabinoid analogues or smoked herbal material of uncertain composition and irregular bioavailability. As a result, the scientific evaluation of medicinal cannabis in humans is still in its infancy. New possibilities in human research have been opened up by the discovery of the endocannabinoid system, a rapidly expanding knowledge of cannabinoid pharmacology, and a more sympathetic political environment in several countries. More and more scientists and clinicians are becoming interested in exploring the potential of cannabis-based medicines. Future targets will extend beyond symptom relief into disease modification, and already cannabinoids seem to offer particular promise in the treatment of certain inflammatory and neurodegenerative conditions. This chapter will begin with an outline of the development and current status of legal controls pertaining to cannabis, following which the existing human research will be reviewed. Some key safety issues will then be considered, and the chapter will conclude with some suggestions as to future directions for human research. PMID:16596794

Robson, P

2005-01-01

202

Defining the habenula in human neuroimaging studies.  

PubMed

Recently there has been renewed interest in the habenula; a pair of small, highly evolutionarily conserved epithalamic nuclei adjacent to the medial dorsal (MD) nucleus of the thalamus. The habenula has been implicated in a range of behaviours including sleep, stress and pain, and studies in non-human primates have suggested a potentially important role in reinforcement processing, putatively via its effects on monoaminergic neurotransmission. Over the last decade, an increasing number of neuroimaging studies have reported functional responses in the human habenula using functional magnetic resonance imaging (fMRI). However, standard fMRI analysis approaches face several challenges in isolating signal from this structure because of its relatively small size, around 30 mm(3) in volume. In this paper we offer a set of guidelines for locating and manually tracing the habenula in humans using high-resolution T1-weighted structural images. We also offer recommendations for appropriate pre-processing and analysis of high-resolution functional magnetic resonance imaging (fMRI) data such that signal from the habenula can be accurately resolved from that in surrounding structures. PMID:22986224

Lawson, Rebecca P; Drevets, Wayne C; Roiser, Jonathan P

2012-09-08

203

A Qualitative Study of Limited Access Permit Dental Hygienists in Oregon  

Microsoft Academic Search

Many states have adopted alternative oral health care delivery systems that include expanded roles for dental hygien- ists. This qualitative study was designed to evaluate the impact of the Limited Access Permit (LAP) legislation in Oregon and to understand the relationship between dental hygienists and dentists within this delivery system. The snowball sampling technique was used to identify LAP dental

Ann M. Battrell; Cynthia C. Gadbury-Amyot; Pamela R. Overman

2008-01-01

204

COMPARATIVE KINETIC STUDIES OF NITRATE-LIMITED GROWTH AND NITRATE UPTAKE IN PHYTOPLANKTON IN CONTINUOUS CULTURE  

EPA Science Inventory

A comparative kinetic study of nitrate-limited growth and nitrate uptake was carried out in chemostat cultures of Ankistrodesmus falcatus, Asterionella formosa, Fragilaria crotonensis. In each species growth rate (microgram) was related to total cell nitrogen or cell quota (q) by...

205

A qualitative case study to identify possible barriers that limit effective elementary science education  

Microsoft Academic Search

The purpose of this case study was to identify barriers that limit the effectiveness of elementary teachers in the teaching of science. It is of the utmost urgency that barriers be first identified, so that possible solutions can be explored to bring about the improvement of elementary science education. This urgency has been imposed by the scheduled national testing of

Donald Carey Foster

2006-01-01

206

SCHELLENG IN RETROSPECT - A SYSTEMATIC STUDY OF BOW FORCE LIMITS FOR BOWED VIOLIN STRINGS  

Microsoft Academic Search

An experimental study of the upper and lower bow force limits for bowed violin strings is reported. A bowing machine was used to perform bow strokes with a real violin bow on steel D and E strings mounted on a rigid monochord and on a violin, respectively. Measurements were systematically performed for 24 values of bow force and 11 values

Erwin Schoonderwaldt; Knut Guettler; Anders Askenfelt

2007-01-01

207

COMPARATIVE KINETIC STUDIES OF PHOSPHATE-LIMITED GROWTH AND PHOSPHATE UPTAKE IN PHYTOPLANKTON IN CONTINUOUS CULTURE  

EPA Science Inventory

A comparative kinetic study of phosphate-limited growth and phosphate uptake was carried out in chemostat cultures of Anabaena flos-aquae Lyng. Breb., Ankistrodesmus falcatus (Corda) Ralfs, Asterionella formosa Hass., Fragilaria crotonensis Kitt., and Microcystis sp. Lemm. For ea...

208

Detecting directional coupling in the human epileptic brain: Limitations and potential pitfalls  

NASA Astrophysics Data System (ADS)

We study directional relationships—in the driver-responder sense—in networks of coupled nonlinear oscillators using a phase modeling approach. Specifically, we focus on the identification of drivers in clusters with varying levels of synchrony, mimicking dynamical interactions between the seizure generating region (epileptic focus) and other brain structures. We demonstrate numerically that such an identification is not always possible in a reliable manner. Using the same analysis techniques as in model systems, we study multichannel electroencephalographic recordings from two patients suffering from focal epilepsy. Our findings demonstrate that—depending on the degree of intracluster synchrony—certain subsystems can spuriously appear to be driving others, which should be taken into account when analyzing field data with unknown underlying dynamics.

Osterhage, Hannes; Mormann, Florian; Wagner, Tobias; Lehnertz, Klaus

2008-01-01

209

Energy Engineering Analysis Program, Limited Energy Study of Steam Distribution Systems, Hawthorne Army Ammunition Depot, Hawthorne, Nevada.  

National Technical Information Service (NTIS)

This report summarizes all work of the Limited Energy Study of Steam Distribution Systems, Energy Engineering Analysis Program, Hawthorne Army Ammunition Depot (HWAAD), Nevada. The purpose of this limited energy study is to evaluate steam distribution and...

1995-01-01

210

Helium exhaust and transport studies with the ALT-II pump limiter in the TEXTOR tokamak  

SciTech Connect

The first encouraging experiments demonstrating direct, explicit control of the He{sup 2+} density in a tokamak plasma have been performed in the TEXTOR tokamak with the Advanced Limiter Test-II pump limiter. Helium is injected in a short gas puff from the outside of the plasma, is observed to reach the plasma core, and then is readily removed from the plasma. An exhaust efficiency of {approximately}8% is obtained. Active charge-exchange spectroscopy is used to study the exhaust and transport of He{sup 2+} within the plasma, and the density evolution is modeled with a diffusive-convective transport code.

Hillis, D.L.; Finken, K.H.; Hogan, J.T.; Dippel, K.H.; Moyer, R.A.; Pospieszczyk, A.; Rusbueldt, D.; Akaishi, K.; Conn, R.W.; Euringer, H.; Gray, D.S.; Horton, L.D.; Hulse, R.A.; Isler, R.C.; Klepper, C.C.; Mioduszewski, P.K.; Miyahara, A.; Wolf, G.H. (Oak Ridge National Laboratory, Oak Ridge, TN (USA) Institut fuer Plasmaphysik, Association EURATOM-Kernforschungsanlage, Forschungszentrum Juelich, D-5170 Juelich (Federal Republic of Germany) Institute of Plasma and Fusion Research, University of California, Los Angeles, CA (USA) National Institute for Fusion Science, Nagoya, Japan Plasma Physics Laboratory, Princeton University, Princeton, NJ (USA))

1990-11-05

211

Risk assessment of diesel exhaust and lung cancer: combining human and animal studies after adjustment for biases in epidemiological studies  

Microsoft Academic Search

Background  Risk assessment requires dose-response data for the evaluation of the relationship between exposure to an environmental stressor\\u000a and the probability of developing an adverse health effect. Information from human studies is usually limited and additional\\u000a results from animal studies are often needed for the assessment of risks in humans. Combination of risk estimates requires\\u000a an assessment and correction of the

Xanthi Pedeli; Gerard Hoek; Klea Katsouyanni

2011-01-01

212

Preliminary Study of Ideal Operational MHD Beta Limit in HL-2A Tokamak Plasmas  

NASA Astrophysics Data System (ADS)

Magnetohydrodynamic (MHD) n = 1 kink mode with n the toroidal mode number is studied and the operational beta limit, constrained by the mode, is calculated for the equilibrium of HL-2A by using the GATO code. Approximately the same beta limit is obtained for configurations with a value of the axial safety factor q0 both larger and less than 1. Without the stabilization of the conducting wall, the beta limit is found to be 0.821% corresponding to a normalized beta value of ?cN = 2.56 for a typical HL-2A discharge with a plasma current Ip = 0.245 MA, and the scaling of ?cN ~constant is confirmed.

Shen, Yong; Dong, Jiaqi; He, Hongda; D. Turnbull, A.

2009-04-01

213

Study on forming limit diagrams prediction using a phenomenological and a physical approach of plasticity theory  

Microsoft Academic Search

In the present work a study on the prediction of the Forming Limit Diagrams is developed, by using a phenomenological and a physical approach of the plasticity theory. Two advanced constitutive models of the plastic anisotropy are considered, namely the Yld'96 Barlat phenomenological yield function and a combined model of texture and strain-path-induced anisotropy. The studied material is a bake-hardened

M. C. Butuc; A. Barata da Rocha; J. J. Gracier; J. Ferreira Duarte

2003-01-01

214

Dual rover human habitation field study  

NASA Astrophysics Data System (ADS)

For the last 3 years, the National Aeronautics and Space Administration (NASA) has been testing a pressurized rover prototype in the deserts of Arizona to obtain human-in-the-loop performance data. This year's field trial consisted of operating two rovers simultaneously while embarking on two 7-day flight-like exploration missions. During the 2010 Desert Research and Technology Studies (DRATS) at Black Point Lava Flow and SP Mountain in Arizona, NASA human factors investigators, in cooperation with other engineers and scientists, collected data on both the daily living and working within and around the Space Exploration Vehicle (SEV). Both objective and subjective data were collected using standard human factors metrics. Over 305 h of crew habitability data were recorded during the field trial with 65 elements of habitation examined. Acceptability of the vehicles over the course of the missions was considered satisfactory by the majority of the crews. As with previous testing, habitation was considered acceptable by the crews, but some issues concerning stowage, Waste Containment System (WCS) volume, and sleep curtains need to be considered for redesign for the next generation vehicle.

Litaker, Harry L.; Thompson, Shelby G.; Szabo, Richard; Twyford, Evan S.; Conlee, Carl S.; Howard, Robert L.

2013-10-01

215

Human resource management and cultural diversity: a case study in Mozambique  

Microsoft Academic Search

A limited number of studies in Africa have reconciled human resource management (HRM) programs with cultural diversity as represented by Hofstede's cultural dimensions. The objective of this study is to examine how Western-based HRM can be modified to embrace cultural diversity in an African context. A mixed methodology employed a survey, as well as a case study in Mozambique. The

Kurt Sartorius; Andrés Merino; Teresa Carmichael

2011-01-01

216

Recombinant enzymes overexpressed in bacteria show broad catalytic specificity of human cytochrome P450 2W1 and limited activity of human cytochrome P450 2S1.  

PubMed

Human cytochromes P450 2S1 and 2W1 have received only limited attention with regard to characterization of function. Both cytochromes P450 have been reported to be overexpressed in human tumors, and cytochrome P450 2S1 is induced by carcinogenic polycyclic hydrocarbons. We report methods for high-level expression and purification of both cytochromes P450 from Escherichia coli, with the goal of establishing function. The level of expression of human cytochrome P450 2W1 achieved using codon optimization for E. coli was 1800 nmol of cytochrome P450 per liter of culture, the highest level achieved in this laboratory to date. Assays with a number of the typical cytochrome P450 substrates showed no detectable activity, including some for which qualitative reports have appeared in the literature. Cytochrome P450 2W1 catalyzed benzphetamine N-demethylation (k(cat), 3.8/min) and arachidonic acid oxidation, albeit at a very low rate (approximately 0.05/min). In a umu genotoxicity screen, cytochrome P450 2W1 catalyzed the activation of several procarcinogens, particularly polycyclic hydrocarbon diols, but cytochrome P450 2S1 did not. The bioactivation of procarcinogens by cytochrome P450 2W1 may be of significance in the context of reports of preferential expression of the enzyme in tumors, in that activation of procarcinogens could lead to the accumulation of mutations and enhance the carcinogenic process. PMID:16551781

Wu, Zhong-Liu; Sohl, Christal D; Shimada, Tsutomu; Guengerich, F Peter

2006-03-21

217

The Humanized NOD/SCID Mouse as a Preclinical Model to Study the Fate of Encapsulated Human Islets  

PubMed Central

Despite encouraging results in animal models, the transplantation of microencapsulated islets into humans has not yet reached the therapeutic level. Recent clinical trials using microencapsulated human islets in barium alginate showed the presence of dense fibrotic overgrowth around the microcapsules with no viable islets. The major reason for this is limited understanding of what occurs when encapsulated human islets are allografted. This warrants the need for a suitable small animal model. In this study, we investigated the usefulness of NOD/SCID mice reconstituted with human PBMCs (called humanized NOD/SCID mice) as a preclinical model. In this model, human T cell engraftment could be achieved, and CD45+ cells were observed in the spleen and peripheral blood. Though the engrafted T cells caused a small fibrotic overgrowth around the microencapsulated human islets, this failed to stop the encapsulated islets from functioning in the diabetic recipient mice. The ability of encapsulated islets to survive in this mouse model might partly be attributed to the presence of Th2 cytokines IL-4 and IL-10, which are known to induce graft tolerance. In conclusion, this study showed that the hu-NOD/SCID mouse is not a suitable preclinical model to study the allograft rejection mechanisms of encapsulated human islets. As another result, the maintained viability of transplanted islets on the NOD/SCID background emphasized a critical role of protective mechanisms in autoimmune diabetes transplanted subjects due to specific immunoregulatory effects provided by IL-4 and IL-10.

Vaithilingam, Vijayaganapathy; Oberholzer, Jose; Guillemin, Gilles J.; Tuch, Bernard E.

2010-01-01

218

Composition of human excreta — a case study from Southern Thailand  

Microsoft Academic Search

In Thailand, human excreta might be recycled into agricultural soils as a supplement to commercial fertiliser and thereby enrich the general fertility of the soils. However, for Thailand an adequate knowledge of the quality of human excreta, in order to assess its fertiliser potential, is not available. A literature survey revealed only very limited information of the chemical composition and

N. L. Schouw; S. Danteravanich; H. Mosbaek; J. C. Tjell

2002-01-01

219

Work, Productivity, and Human Performance: Practical Case Studies in Ergonomics, Human Factors and Human Engineering.  

ERIC Educational Resources Information Center

This book contains 12 case histories, each based on a real-life problem, that show how a manager can use common sense, knowledge, and interpersonal skills to solve problems in human performance at work. Each case study describes a worker's problem and provides background information and an assignment; solutions are suggested. The following cases…

Fraser, T. M.; Pityn, P. J.

220

Sorption studies of human keratinized tissues  

NASA Astrophysics Data System (ADS)

Water content is known to be the most important single parameter for keratinized tissue to remain its vital functions. In that sense, a general knowledge of the water binding properties is of great interest, and a reliable measurement setup must be found. Also, revealing the sorption properties of human keratinized tissues is vital towards a calibration of susceptance based skin hydration measurements that already is an important diagnostic tool in clinical dermatology, and we will see that any hysteresis will complicate such a calibration further. In this study we investigated the sorption properties of keratinized tissues such as human epidermal stratum corneum (SC), hair and nail. The study was performed under controlled environmental conditions with a dynamic vapor sorption (DVS) instrument, and the water uptake of the keratinized test samples was measured as the relative humidity in the ambient air was altered step-wisely. In this study, vital and characteristic water sorption properties such as the isotherm, relative water uptake, and hysteresis were investigated and will be discussed.

Johnsen, G. K.; Martinsen, Ø. G.; Grimnes, Sverre

2010-04-01

221

Drosophila melanogaster in the Study of Human Neurodegeneration  

PubMed Central

Human neurodegenerative diseases are devastating illnesses that predominantly affect elderly people. The majority of the diseases are associated with pathogenic oligomers from misfolded proteins, eventually causing the formation of aggregates and the progressive loss of neurons in the brain and nervous system. Several of these proteinopathies are sporadic and the cause of pathogenesis remains elusive. Heritable forms are associated with genetic defects, suggesting that the affected protein is causally related to disease formation and/or progression. The limitations of human genetics, however, make it necessary to use model systems to analyse affected genes and pathways in more detail. During the last two decades, research using the genetically amenable fruitfly has established Drosophila melanogaster as a valuable model system in the study of human neurodegeneration. These studies offer reliable models for Alzheimer’s, Parkinson’s, and motor neuron diseases, as well as models for trinucleotide repeat expansion diseases, including ataxias and Huntington’s disease. As a result of these studies, several signalling pathways including phosphatidylinositol 3-kinase (PI3K)/Akt and target of rapamycin (TOR), c-Jun N-terminal kinase (JNK) and bone morphogenetic protein (BMP) signalling, have been shown to be deregulated in models of proteinopathies, suggesting that two or more initiating events may trigger disease formation in an age-related manner. Moreover, these studies also demonstrate that the fruitfly can be used to screen chemical compounds for their potential to prevent or ameliorate the disease, which in turn can directly guide clinical research and the development of novel therapeutic strategies for the treatment of human neurodegenerative diseases.

Hirth, Frank

2010-01-01

222

A strategy to study genotoxicity: application to aquatic toxins, limits and solutions.  

PubMed

Humans can be exposed to aquatic toxins mainly through contamination of food and water (drinking and recreational). Among these toxins, contamination by both phycotoxins occurring in shellfish and cyanotoxins mostly involved in freshwater bodies are of concern for public health. Whereas regulations exist to evaluate the genotoxicity of most compounds to which humans are exposed, including drugs and chemicals, no regulations have been established for these compounds. In this paper, we show that the same strategy including both in vitro and in vivo tests can be followed to evaluate the genotoxicity of aquatic toxins (phycotoxins and cyanotoxins). However, this strategy encountered different limits which arise when completing an overview of the genotoxic potential of toxins. The most restrictive one is undoubtedly the low amount (even the lack sometimes) of purified toxins available. Solutions and recommendations for testing the genotoxicity of aquatic toxins are suggested to overcome the specific problems encountered with these compounds. It must be kept in mind that recent developments in drug toxicology should be considered and that experiments must be conducted in respect of the 3Rs principle of refinement, reduction and replacement for animal experimentation. PMID:20446082

Fessard, Valérie; Le Hégarat, Ludovic

2010-05-07

223

Noncanonical NOTCH Signaling Limits Self-Renewal of Human Epithelial and Induced Pluripotent Stem Cells through ROCK Activation.  

PubMed

NOTCH plays essential roles in cell fate specification during embryonic development and in adult tissue maintenance. In keratinocytes, it is a key inducer of differentiation. ROCK, an effector of the small GTPase Rho, is also implicated in keratinocyte differentiation, and its inhibition efficiently potentiates immortalization of human keratinocytes and greatly improves survival of dissociated human pluripotent stem cells. However, the molecular basis for ROCK activation is not fully established in these contexts. Here we provide evidence that intracellular forms of NOTCH1 trigger the immediate activation of ROCK1 independent of its transcriptional activity, promoting differentiation and resulting in decreased clonogenicity of normal human keratinocytes. Knockdown of NOTCH1 abrogated ROCK1 activation and conferred sustained clonogenicity upon differentiation stimuli. Treatment with a ROCK inhibitor, Y-27632, or ROCK1 silencing substantially rescued the growth defect induced by activated NOTCH1. Furthermore, we revealed that impaired self-renewal of human induced pluripotent stem cells upon dissociation is, at least in part, attributable to NOTCH-dependent ROCK activation. Thus, the present study unveils a novel NOTCH-ROCK pathway critical for cellular differentiation and loss of self-renewal capacity in a subset of immature cells. PMID:24019071

Yugawa, Takashi; Nishino, Koichiro; Ohno, Shin-Ichi; Nakahara, Tomomi; Fujita, Masatoshi; Goshima, Naoki; Umezawa, Akihiro; Kiyono, Tohru

2013-09-09

224

Study of the W +W ? ? process and limits on anomalous quartic gauge boson couplings at LEP  

Microsoft Academic Search

The process e+e??W+W?? is studied using the data collected by the L3 detector at LEP. New results, corresponding to an integrated luminosity of 427.4 pb?1 at centre-of-mass energies from 192 to 207 GeV, are presented.The W+W?? cross sections are measured to be in agreement with Standard Model expectations. No hints of anomalous quartic gauge boson couplings are observed. Limits at 95% confidence

P. Achard; O. Adriani; M. Aguilar-Benitez; J. Alcaraz; G. Alemanni; J. Allaby; A. Aloisio; M. G. Alviggi; H. Anderhub; V. P. Andreev; F. Anselmo; A. Arefiev; T. Azemoon; T. Aziz; P. Bagnaia; A. Bajo; G. Baksay; L. Baksay; S. V. Baldew; S. Banerjee; A. Barczyk; R. Barillère; P. Bartalini; M. Basile; N. Batalova; R. Battiston; A. Bay; F. Becattini; U. Becker; F. Behner; L. Bellucci; R. Berbeco; J. Berdugo; P. Berges; B. Bertucci; B. L. Betev; M. Biasini; M. Biglietti; A. Biland; J. J. Blaising; S. C. Blyth; G. J. Bobbink; A. Böhm; L. Boldizsar; B. Borgia; S. Bottai; D. Bourilkov; M. Bourquin; S. Braccini; J. G. Branson; F. Brochu; A. Buijs; J. D. Burger; W. J. Burger; X. D. Cai; M. Capell; G. Carlino; A. Cartacci; J. Casaus; F. Cavallari; N. Cavallo; C. Cecchi; M. Cerrada; M. Chamizo; Y. H. Chang; M. Chemarin; A. Chen; G. Chen; H. F. Chen; H. S. Chen; G. Chiefari; L. Cifarelli; F. Cindolo; I. Clare; R. Clare; G. Coignet; N. Colino; S. Costantini; S. Cucciarelli; P. Déglon; J. Debreczeni; A. Degré; K. Deiters; E. Delmeire; P. Denes; F. DeNotaristefani; M. Diemoz; M. Dierckxsens; C. Dionisi; M. Dittmar; A. Doria; M. T. Dova; D. Duchesneau; P. Duinker; B. Echenard; A. Eline; A. Engler; F. J. Eppling; A. Ewers; P. Extermann; M. A. Falagan; S. Falciano; A. Favara; J. Fay; O. Fedin; M. Felcini; T. Ferguson; H. Fesefeldt; E. Fiandrini; J. H. Field; F. Filthaut; P. H. Fisher; W. Fisher; I. Fisk; G. Forconi; K. Freudenreich; C. Furetta; Yu. Galaktionov; S. N. Ganguli; P. Garcia-Abia; M. Gataullin; S. Gentile; S. Giagu; Z. F. Gong; G. Grenier; O. Grimm; M. W. Gruenewald; M. Guida; V. K. Gupta; A. Gurtu; L. J. Gutay; D. Haas; D. Hatzifotiadou; T. Hebbeker; A. Hervé; J. Hirschfelder; H. Hofer; M. Hohlmann; G. Holzner; S. R. Hou; Y. Hu; B. N. Jin; L. W. Jones; I. Josa-Mutuberr??a; D. Käfer; M. Kaur; M. N. Kienzle-Focacci; J. K. Kim; J. Kirkby; W. Kittel; A. Klimentov; A. C. König; M. Kopal; V. Koutsenko; M. Kräber; R. W. Kraemer; W. Krenz; A. Krüger; A. Kunin; I. Laktineh; G. Landi; M. Lebeau; A. Lebedev; P. Lebrun; P. Lecomte; P. Lecoq; R. Leiste; P. Levtchenko; C. Li; S. Likhoded; C. H. Lin; W. T. Lin; F. L. Linde; L. Lista; Z. A. Liu; W. Lohmann; E. Longo; Y. S. Lu; K. Lübelsmeyer; C. Luci; L. Luminari; W. Lustermann; W. G. Ma; L. Malgeri; A. Malinin; C. Maña; D. Mangeol; J. Mans; J. P. Martin; F. Marzano; K. Mazumdar; R. R. McNeil; S. Mele; L. Merola; M. Meschini; W. J. Metzger; A. Mihul; H. Milcent; G. Mirabelli; J. Mnich; G. B. Mohanty; G. S. Muanza; A. J. M. Muijs; B. Musicar; M. Musy; S. Nagy; S. Natale; M. Napolitano; F. Nessi-Tedaldi; H. Newman; T. Niessen; A. Nisati; H. Nowak; R. Ofierzynski; G. Organtini; C. Palomares; D. Pandoulas; P. Paolucci; R. Paramatti; G. Passaleva; S. Patricelli; T. Paul; M. Pauluzzi; C. Paus; F. Pauss; M. Pedace; S. Pensotti; D. Perret-Gallix; B. Petersen; D. Piccolo; F. Pierella; M. Pioppi; P. A. Piroué; E. Pistolesi; V. Plyaskin; M. Pohl; V. Pojidaev; J. Pothier; D. O. Prokofiev; J. Quartieri; G. Rahal-Callot; M. A. Rahaman; P. Raics; N. Raja; R. Ramelli; P. G. Rancoita; R. Ranieri; A. Raspereza; P. Razis; D. Ren; M. Rescigno; S. Reucroft; S. Riemann; K. Riles; B. P. Roe; L. Romero; A. Rosca; S. Rosier-Lees; S. Roth; C. Rosenbleck; B. Roux; J. A. Rubio; G. Ruggiero; H. Rykaczewski; A. Sakharov; S. Saremi; S. Sarkar; J. Salicio; E. Sanchez; M. P. Sanders; C. Schäfer; V. Schegelsky; S. Schmidt-Kaerst; D. Schmitz; H. Schopper; D. J. Schotanus; G. Schwering; C. Sciacca; L. Servoli; S. Shevchenko; N. Shivarov; V. Shoutko; E. Shumilov; A. Shvorob; T. Siedenburg; D. Son; P. Spillantini; M. Steuer; D. P. Stickland; B. Stoyanov; A. Straessner; K. Sudhakar; G. Sultanov; L. Z. Sun; S. Sushkov; H. Suter; J. D. Swain; Z. Szillasi; X. W. Tang; P. Tarjan; L. Tauscher; L. Taylor; B. Tellili; D. Teyssier; C. Timmermans; S. M. Ting; S. C. Tonwar; J. Tóth; C. Tully; K. L. Tung; J. Ulbricht; E. Valente; V. Veszpremi; G. Vesztergombi; I. Vetlitsky; D. Vicinanza; P. Violini; G. Viertel; S. Villa; M. Vivargent; S. Vlachos; I. Vodopianov; H. Vogel; H. Vogt; I. Vorobiev; A. A. Vorobyov; M. Wadhwa; W. Wallraff; X. L. Wang; Z. M. Wang; M. Weber; P. Wienemann; H. Wilkens; S. Wynhoff; L. Xia; Z. Z. Xu; J. Yamamoto; B. Z. Yang; C. G. Yang; H. J. Yang; M. Yang; S. C. Yeh; An. Zalite; Yu. Zalite; Z. P. Zhang; J. Zhao; G. Y. Zhu; R. Y. Zhu; H. L. Zhuang; A. Zichichi; G. Zilizi; B. Zimmermann; M. Z. Zöller

2002-01-01

225

Limitations of rapid HIV1 tests during screening for trials in Uganda: diagnostic test accuracy study  

Microsoft Academic Search

Objective To evaluate the limitations of rapid tests for HIV-1.Design Diagnostic test accuracy study.Setting Rural Rakai, Uganda.Participants 1517 males aged 15-49 screened for trials of circumcision for HIV prevention.Main outcome measures Sensitivity, specificity, negative predictive values, and positive predictive values of an algorithm using three rapid tests for HIV, compared with the results of enzyme immunoassay and western blotting as

Ronald H Gray; Fredrick Makumbi; David Serwadda; Tom Lutalo; Fred Nalugoda; Pius Opendi; Godfrey Kigozi; Steven J Reynolds; Nelson K Sewankambo; Maria J Wawer

2007-01-01

226

Mass Transfer Limited Enhanced Bioremediation at Dnapl Source Zones: a Numerical Study  

NASA Astrophysics Data System (ADS)

The success of enhanced bioremediation of dense non-aqueous phase liquids (DNAPLs) relies on accelerating contaminant mass transfer from the organic to the aqueous phase, thus enhancing the depletion of DNAPL source zones compared to natural dissolution. This is achieved by promoting biological activity that reduces the contaminant's aqueous phase concentration. Although laboratory studies have demonstrated that high reaction rates are attainable by specialized microbial cultures in DNAPL source zones, field applications of the technology report lower reaction rates and prolonged remediation times. One possible explanation for this phenomenon is that the reaction rates are limited by the rate at which the contaminant partitions from the DNAPL to the aqueous phase. In such cases, slow mass transfer to the aqueous phase reduces the bioavailability of the contaminant and consequently decreases the potential source zone depletion enhancement. In this work, the effect of rate limited mass transfer on bio-enhanced dissolution of DNAPL chlorinated ethenes is investigated through a numerical study. A multi-phase, multi-component groundwater transport model is employed to simulate DNAPL mass depletion for a range of source zone scenarios. Rate limited mass transfer is modeled by a linear driving force model, employing a thermodynamic approach for the calculation of the DNAPL - water interfacial area. Metabolic reductive dechlorination is modeled by Monod kinetics, considering microbial growth and self-inhibition. The model was utilized to identify conditions in which mass transfer, rather than reaction, is the limiting process, as indicated by the bioavailability number. In such cases, reaction is slower than expected, and further increase in the reaction rate does not enhance mass depletion. Mass transfer rate limitations were shown to affect both dechlorination and microbial growth kinetics. The complex dynamics between mass transfer, DNAPL transport and distribution, and dechlorination kinetics were reflected in a transient, spatially heterogeneous bioavailability number and dissolution enhancement. In agreement with the literature, source zone architecture largely determined the impact of mass transfer on potential dissolution enhancement, with bioavailability decreasing the most at high ganglia to pool ratios. The results of this study suggest that if mass transfer rate limitations are not considered in designing bioremediation applications at DNAPL source zones, the enhancement of DNAPL depletion and the overall effectiveness of enhanced bioremediation may be significantly overestimated.

Kokkinaki, A.; Sleep, B. E.

2011-12-01

227

Insulin Stimulates Liver Glucose Uptake in Humans: An 18F-FDG PET Study  

Microsoft Academic Search

The liver is vital for the regulation of glucose metabolism, but inaccessibility of the organ for direct assessments has limited the study of its metabolic role in vivo. Methods: The effect of insulin and insulin sensitivity (IS) on hepatic glucose uptake was investigated using PET, 18F-FDG, and graphical analysis and 3-compartment modeling in humans. We studied 16 healthy sedentary men

Patricia Iozzo; Fabian Geisler; Vesa Oikonen; Maija Maki; Teemu Takala; Olof Solin; Ele Ferrannini; Juhani Knuuti; Pirjo Nuutila

228

The dog as a model to study human epididymal function at a molecular level  

Microsoft Academic Search

Approaches to study human epididymal functions are limited. Therefore, suitable animal models are highly desirable, yet difficult to find among the few species studied on a molecular level to date. This review summarizes our progress in the development of the canine epididymis as an alternative model. Dogs are biomedically a key species because they are subject to many of the

Christiane Kirchhoff

2002-01-01

229

Parsimonious modeling of vegetation dynamics for ecohydrologic studies of water-limited ecosystems  

NASA Astrophysics Data System (ADS)

The structure and function of vegetation regulate fluxes across the biosphere-atmosphere interface with large effects in water-limited ecosystems. Vegetation dynamics are often neglected in hydrological modeling except for simple prescriptions of seasonal phenology. However, changes in vegetation densities, influencing the partitioning of incoming solar energy into sensible and latent heat fluxes, can result in long-term changes in both local and global climates with resulting feedbacks on vegetation growth. This paper seeks a simple vegetation dynamics model (VDM) for simulation of the leaf area index (LAI) dynamics in hydrologic models. Five variants of a VDM are employed, with a range of model complexities. The VDMs are coupled to a land surface model (LSM), with the VDM providing the LAI evolution through time and the LSM using this to compute the land surface fluxes and update the soil water contents. We explore the models through case studies of water-limited grass fields in California (United States) and North Carolina (United States). Results show that a simple VDM, simulating only the living aboveground green biomass (i.e., with low parameterization), is able to accurately simulate the LAI. Results also highlight the importance of including the VDM in the LSM when studying the climate-soil-vegetation interactions over moderate to long timescales. The inclusion of the VDM in the LSM is demonstrated to be essential for assessing the impact of interannual rainfall variability on the water budget of a water limited region.

Montaldo, Nicola; Rondena, Roberta; Albertson, John D.; Mancini, Marco

2005-10-01

230

Periodontitis is related to lung volumes and airflow limitation- a cross-sectional study.  

PubMed

This study aims to assess the potential association of periodontal diseases with lung volumes and airflow limitation in a general adult population.Based on a representative population sample of the Study of Health in Pomerania (SHIP), 1463 subjects aged 25-85 years were included. Periodontal status was assessed by clinical attachment loss (CAL), probing depth (PD), and number of missing teeth (NoMT). Lung function was measured using spirometry, body plethysmography, and diffusing capacity for carbon monoxide. Linear regression models using fractional polynomials were used to assess associations between periodontal disease and lung function. Fibrinogen and high-sensitive C-reactive protein (hs-CRP) were evaluated as potential intermediate factors.After full adjustment for potential confounders mean CAL was significantly associated with variables of mobile dynamic and static lung volumes, airflow limitation and hyperinflation (p<0.05). Including fibrinogen and hs-CRP did not change coefficients of mean CAL; associations remained statistically significant. Mean CAL was not associated with total lung capacity and diffusing capacity for carbon monoxide. Associations were confirmed for mean PD, extent measures of CAL/PD, and NoMT.Periodontal disease was significantly associated with reduced lung volumes and airflow limitation in this general adult population sample. Systemic inflammation did not provide a mechanism linking both diseases. PMID:23222882

Holtfreter, Birte; Richter, Stefanie; Kocher, Thomas; Dörr, Marcus; Völzke, Henry; Ittermann, Till; Obst, Anne; Schäper, Christoph; John, Ulrich; Meisel, Peter; Grotevendt, Anne; Felix, Stephan B; Ewert, Ralf; Gläser, Sven

2012-12-01

231

Transport properties of triarylamine based dendrimers studied by space charge limited current transients  

NASA Astrophysics Data System (ADS)

We have studied hole transport in triarylamine based dendrimer using space-charge-limited current transient technique. A mobility of 8 × 10-6 cm2/(V s) and a characteristic detrapping time of about 100 ms have been obtained. We found that quasi-ohmic contact is formed with gold. The obtained mobility differs from the apparent one given by the analysis of stationary current-voltage characteristics because of a limited contact efficiency. The comparison between transients obtained from fresh and aged samples reveals no change in mobility with aging. The deterioration of electrical properties is exclusively caused by trap formation and accumulation of ionic conducting impurities. Finally, repeated transient measurements have been applied to analyze the dynamics of charge trapping process.

Szymanski, Marek Z.; Kulszewicz-Bajer, Irena; Faure-Vincent, Jérôme; Djurado, David

2012-08-01

232

Genetic modeling of ovarian phenotypes in mice for the study of human polycystic ovary syndrome.  

PubMed

Polycystic ovary syndrome (PCOS) presents with a range of clinical complications including hyperandrogenism, polycystic ovaries, chronic oligo/anovulation, infertility, and metabolic alterations related to insulin resistance. Because the mechanism by which this disorder develops is poorly understood, information from experimental models of human disease phenotypes may help to define the mechanisms for the initiation and development of PCOS-related pathological events. The establishment of animal models compatible with human PCOS is challenging, and applying the lessons learned from these models to human PCOS is often complicated. In this mini-review we provide examples of currently available genetic mouse models, their ovarian phenotypes, and their possible relationship to different aspects of human PCOS. Because of the practical and ethical limitations of studying PCOS-related events in humans, our understanding of the mechanisms that contribute to the etiology of human PCOS may be enhanced through further study of these transgenic and knockout mouse models. PMID:23390562

Feng, Yi; Li, Xin; Shao, Ruijin

2013-01-21

233

Software defined radar studies of human motion signatures  

Microsoft Academic Search

The detection and monitoring of human motion with radar has numerous applications in surveillance, urban military operations, search-and-rescue, and other areas. Recent studies have shown that movements of humans generate unique micro-Doppler signatures that can be exploited to classify human motions. This motivates an improved understanding of human Doppler signatures. Numerous simulations and measurements of human “dismount” signatures has been

J. T. Johnson; N. Majurec; M. Frankford; E. Culpepper; J. Reynolds; J. Tenbarge; L. Westbrook

2012-01-01

234

Comparative study of limited-range wavelength conversion policies for asynchronous optical packet switching  

NASA Astrophysics Data System (ADS)

We study an asynchronous optical packet (OP)-switching node equipped with a number of limited range (LR) wavelength converters shared per output link. We study both circular and noncircular LR-wavelength-conversion schemes. A wavelength conversion policy governs the selection of the outgoing wavelength for an OP if the incoming wavelength is in use. Through simulations, we show that the so-called far-conversion policy for which the OP is switched onto the farthest available wavelength in the tuning range, outperforms the other policies we studied. We point out the clustering effect in the use of wavelengths to explain this phenomenon. We also provide an approximate analytical method to find the packet-blocking probability in circular-type LR-wavelength-conversion systems. Based on the simulation results, the approximate method appears to lead to a lower bound for blocking probabilities for all the conversion policies we study.

Dogan, Kaan; Gunalay, Yavuz; Akar, Nail

2007-02-01

235

Where to look: a study of human-robot engagement  

Microsoft Academic Search

This paper reports on a study of human subjects with a robot designed to mimic human conversational gaze behavior in collaborative conversation. The robot and the human subject together performed a demonstration of an invention created at our laboratory; the demonstration lasted 3 to 3.5 minutes. We briefly discuss the robot architecture and then focus the paper on a study

Candace L. Sidner; Cory D. Kidd; Christopher Lee; Neal Lesh

2004-01-01

236

Growth hormone limits the brain/body development before birth in relation to sex, grasp-reflex asymmetry and familial sinistrality of human neonates.  

PubMed

Since there is no theological explanation for high growth hormone (GH) concentrations in perinatal blood, GH concentrations from umbilical cord blood were studied in relation to body weight and head circumference (brain weight) in the human neonates. GH exhibited inverse correlations with body weight and head circumference in these subjects, which depended upon sex, familial sinistrality (FS), and grasp-reflex dominance. This implies that GH may adversely influence the brain/body development during perinatal development on the basis of a genetically predetermined brain organization. It was suggested that the lipolytic and anti-insulin GH effects may be responsible for its body-weight reducing effects; the anti-insulin GH actions may be responsible for its brain-weight reducing effects. As a result of these actions, GH may limit the brain/body development, to induce a balanced growth during perinatal period. PMID:7591507

Tan, U

1995-05-01

237

A YBCO-coated conductor for a fault current limiter: architecture influences and optical study  

NASA Astrophysics Data System (ADS)

YBaCuO-coated conductors (CC) are particularly interesting for the electric grid, especially for superconducting (SC) fault current limiters (FCL). This innovative device should play an important part in the future electric energy landscape. New network diagrams are indeed imagined with DC buses. The SC FCL would solve the delicate problem of DC fault currents. We have studied several YBaCuO-coated conductors with different architectures. A test bench for optical measurements has been developed to study the bubble development during limitation or over-current operation. The observations give useful information about the quench initiation and its propagation. The images were recorded every 0.2 ms (or less). Preliminary experiments have been carried out using a copper strip. Several operating temperatures have been investigated and important differences have been observed in some cases. The different YBaCuO CC studied show very different behaviours. Bubbles appear under the shape of strips across the tape or show a homogeneous behaviour. These behaviours are correlated by electrical measurements.

Nguyen, N. T.; Tixador, P.

2010-02-01

238

Restless legs syndrome and functional limitations among American elders in the Health and Retirement Study  

PubMed Central

Background Restless legs syndrome (RLS) is a common condition associated with decreased quality of life in older adults. This study estimates the prevalence, risk factors, and functional correlates of among U.S. elders. Methods Subjects (n?=?1,008) were sub-sampled from the 2002 cross-sectional interview survey of the Health and Retirement Study (HRS), a nationally representative study of U.S. elders. Symptoms and sleep disturbances consistent with RLS were identified. Activities of daily living (ADL), instrumental activities of daily living (IADL), and limitations for mobility, large muscle groups, gross and fine motor function were measured using standardized questions. Incident functional limitations were detected over six years of observation. Results The prevalence of RLS among U.S. elders born before 1947 was 10.6%. Factors associated with increased prevalence RLS at baseline included: overweight body mass index (multivariate adjusted prevalence ratio?=?1.77; 95% confidence interval (CI) 1.05-2.99); mild-to-moderate pain (2.67, 1.47-4.84) or pain inferring with activity (3.44, 2.00-5.93); three or more chronic medications (2.54, 1.26-5.12), highest quartile of out-of-pocket medical expenses (2.12, 1.17-3.86), frequent falls (2.63, 1.49-4.66), health limiting ability to work (2.91, 1.75-4.85), or problems with early waking or frequent wakening (1.69, 1.09-2.62 and 1.55, 1.00-2.41, respectively). Current alcohol consumption (0.59, 0.37-0.92) and frequent healthcare provider visits (0.49, 0.27-0.90) were associated with decreased RLS prevalence. RLS did not predict incident disability for aggregate measures but was associated with increased risk for specific limitations, including: difficulty climbing several stair flights (multivariate-adjusted hazard ratio?=?2.38, 95% CI 1.39-4.06), prolonged sitting (2.17, 1.25-3.75), rising from a chair (2.54, 1.62-3.99), stooping (2.66, 1.71-4.15), moving heavy objects (1.79, 1.08-2.99), carrying ten pounds (1.61, 1.05-2.97), raising arms (1.76, 1.05-2.97), or picking up a dime (1.97, 1.12-3.46). Conclusions RLS sufferers are more likely to have functional disability, even after adjusting for health status and pain syndrome correlates.

2012-01-01

239

Using humanoid robots to study human behavior  

Microsoft Academic Search

Our understanding of human behavior advances as our humanoid robotics work progresses-and vice versa. This team's work focuses on trajectory formation and planning, learning from demonstration, oculomotor control and interactive behaviors. They are programming robotic behavior based on how we humans “program” behavior in-or train-each other

Christopher G. Atkeson; Joshua G. Hale; Frank Pollick; Marcia Riley; Shinya Kotosaka; S. Schaul; Tomohiro Shibata; Gaurav Tevatia; Ales Ude; Sethu Vijayakumar; Erato Kawato; M. Kawato

2000-01-01

240

Method dependent limits in a study on the natural history of coronary and cerebral atherosclerosis.  

PubMed

Important discrepancies were revealed in a study on human coronary and cerebral atherosclerosis among data furnished by gross inspection and by light microscopy. The character of atherosclerotic lesions, the meaning of the terms "normal intimas" "fatty streaks", "fibrous plaques" and "complicated lesions", the type of the early atherosclerotic lesions, the age period of the onset of these early lesions, their sequence of development, their relationship to advanced lesions--all appeared method dependent. The gross inspection alone led not only to an oversimplified, but also to a distorded view on the natural history of atherosclerosis, since it overlooked the role of intimal necrosis, incorporated microthrombi, fibromuscular plaques, mucoid plaques and foam cell-rich plaques in atherogenesis. The degree and extent to which the early stages of atherosclerotic involvement remained undetected by gross inspection was surprisingly great. The difference between the number of atherosclerotic plaques recorded on microscopic and macroscopic examination of the same vascular segments was statistically significant (p less than 0.01). Our results suggest that all basic studies of human atherosclerosis must include intermingled macroscopic and microscopic examination of the same arterial segments and require the use of an adequate terminology. PMID:7156817

Velican, D; Anghelescu, M; Petrescu, C; Velican, C

241

Toward new understandings of human–animal relationships in sport: a study of Australian jumps racing  

Microsoft Academic Search

The importance of studying human–animal relationships and animal subjectivity is increasingly recognised by social and cultural geographers, particularly in agricultural pursuits. Little research, however, has been undertaken on animals in sport, resulting in a limited understanding of the perceptions and treatment of animals in society. To address this concern, we interrogate print media coverage of the construction and positioning of

Phil McManus; Daniel Montoya

2012-01-01

242

A Study of the Roles of NGOs for North Korean Refugees’ Human Rights  

Microsoft Academic Search

Even though the U.S. government passed a bill supporting North Korean refugees’ human rights, security and other issues create some difficulties in implementing this support. To overcome information and basic knowledge limitations, the U.S. government should cooperate with nonprofit organizations or nongovernmental organizations (NGOs) and other governments in the world. This research is composed of four case studies based on

Jungin Kim

2010-01-01

243

Gene regulation of UDP-galactose synthesis and transport: potential rate-limiting processes in initiation of milk production in humans.  

PubMed

Lactose synthesis is believed to be rate limiting for milk production. However, understanding the molecular events controlling lactose synthesis in humans is still rudimentary. We have utilized our established model of the RNA isolated from breast milk fat globule from seven healthy, exclusively breastfeeding women from 6 h to 42 days following delivery to determine the temporal coordination of changes in gene expression in the carbohydrate metabolic processes emphasizing the lactose synthesis pathway in human mammary epithelial cell. We showed that milk lactose concentrations increased from 75 to 200 mM from 6 to 96 h. Milk progesterone concentrations fell by 65% at 24 h and were undetectable by day 3. Milk prolactin peaked at 36 h and then declined progressively afterward. In concordance with lactose synthesis, gene expression of galactose kinase 2, UDP-glucose pyrophosphorylase 2 (UGP2), and phosphoglucomutase 1 increased 18-, 10-, and threefold, respectively, between 6 and 72 h. Between 6 and 96 h, gene expression of UDP-galactose transporter 2 (SLC35A2) increased threefold, whereas glucose transporter 1 was unchanged. Gene expression of lactose synthase no. 3 increased 1.7-fold by 96 h, whereas ?-lactalbumin did not change over the entire study duration. Gene expression of prolactin receptor (PRLR) and its downstream signal transducer and activator of transcription complex 5 (STAT5) were increased 10- and 2.5-fold, respectively, by 72 h. In summary, lactose synthesis paralleled the induction of gene expression of proteins involved in UDP-galactose synthesis and transport, suggesting that they are potentially rate limiting in lactose synthesis and thus milk production. Progesterone withdrawal may be the signal that triggers PRLR signaling via STAT5, which may in turn induce UGP2 and SLC35A2 expression. PMID:22649065

Mohammad, Mahmoud A; Hadsell, Darryl L; Haymond, Morey W

2012-05-29

244

An Investigation of Genome-Wide Studies Reported Susceptibility Loci for Ulcerative Colitis Shows Limited Replication in North Indians  

PubMed Central

Genome-Wide Association studies (GWAS) of both Crohn's Disease (CD) and Ulcerative Colitis (UC) have unearthed over 40 risk conferring variants. Recently, a meta-analysis on UC revealed several loci, most of which were either previously associated with UC or CD susceptibility in populations of European origin. In this study, we attempted to replicate these findings in an ethnically distinct north Indian UC cohort. 648 UC cases and 850 controls were genotyped using Infinium Human 660W-quad. Out of 59 meta-analysis index SNPs, six were not in the SNP array used in the study. Of the remaining 53 SNPs, four were found monomorphic. Association (p<0.05) at 25 SNPs was observed, of which 15 were CD specific. Only five SNPs namely rs2395185 (HLA-DRA), rs3024505 (IL10), rs6426833 (RNF186), rs3763313 (BTNL2) and rs2066843 (NOD2) retained significance after Bonferroni correction. These results (i) reveal limited replication of Caucasian based meta-analysis results; (ii) reiterate overlapping molecular mechanism(s) in UC and CD; (iii) indicate differences in genetic architecture between populations; and (iv) suggest that resources such as HapMap need to be extended to cover diverse ethnic populations. They also suggest a systematic GWAS in this terrain may be insightful for identifying population specific IBD risk conferring loci and thus enable cross-ethnicity fine mapping of disease loci.

Juyal, Garima; Prasad, Pushplata; Senapati, Sabyasachi; Midha, Vandana; Sood, Ajit; Amre, Devendra; Juyal, Ramesh C.; BK, Thelma

2011-01-01

245

Early experience and depressive disorders: human and non-human primate studies  

Microsoft Academic Search

This paper reviews evidence from both human and non-human primate studies concerning the role of early adverse experiences in the onset and course of adult depressive disorders. Despite accumulating evidence that stressful life events can play a major role in precipitating the onset of depressive episodes in humans, the mechanisms by which early experiences mediate and moderate the risk for

William S Gilmer; William T McKinney

2003-01-01

246

Study on optimum human resources management of Sports Universities  

Microsoft Academic Search

This paper uses modern statistics analysis method to study the human resource management system of Chinese Sports Universities on the impact of teachers' micro-performance, empirical results show that human resources management of sports universities practices and teacher performance are closely related; optimized teacher human resource management system constitutes of talents introduction mechanism, teacher training and participation mechanisms, teacher performance evaluation

Dexin Zou; Bingquan Liu; Chong Jiang

2010-01-01

247

Lack of blood formate accumulation in humans following exposure to methanol vapor at the current permissible exposure limit of 200 ppm  

SciTech Connect

Accumulation of formate, the putative toxic metabolite of methanol, in the blood and the relationship between pulmonary intake and blood methanol concentration were investigated in six human volunteers following a 6-hr exposure to 200 ppm methanol (the current Occupational Safety and Health Administration 8-hr time-weighted average permissible exposure limit). At the end of a 6-hr exposure to 200 ppm methanol at rest, the blood methanol concentration was increased from a mean of 1.8 micrograms/mL to 7.0 micrograms/mL. Under light exercise, the total amount of methanol inhaled during the 6-hr exposure period was 1.8 times that inhaled at rest. However, no statistically significant increase in blood methanol concentration was observed under exercise: the concentrations averaged 8.1 micrograms/mL. Formate did not accumulate in the blood above its background level following the 6-hr exposures to 200 ppm methanol whether subjects were exposed at rest or during exercise. Unlike the data collected from epidemiologic studies, the authors' results were obtained under well-controlled methanol exposure conditions and by using appropriate dietary restrictions. The data show that (1) the biological load of methanol would be the same regardless of whether workers are engaged in light physical activity when they are exposed to methanol vapors below 200 ppm and (2) the formate that is associated with acute methanol toxicities in humans does not accumulate in blood when methanol exposure concentrations are below 200 ppm.

Lee, E.W.; Terzo, T.S.; D'Arcy, J.B.; Gross, K.B.; Schreck, R.M. (Biomedical Science Department, General Motors Research Laboratories, Warren, MI (United States))

1992-02-01

248

Pharmacokinetic and Chemoprevention Studies on Tea in Humans  

PubMed Central

Green tea and its major polyphenols constituents, tea catechins, have been shown to have many health benefits including cancer prevention. Tea catechins and tea catechin metabolites/catabolites are bioavailable in the systemic circulation after oral intake of green tea or green tea catechins. The metabolites/catabolites identified in humans include glucuronide/sulfate conjugates, methylated tea catechin conjugates, and microflora-mediated ring fission products and phenolic acid catabolites. Plasma levels of unchanged tea catechins in humans are mostly in the sub-?M or nM concentration range, which is much lower than the effective concentrations determined in most in vitro studies. However, some of the catechin metabolites/catabolites are present in the systemic circulation at levels much higher than those of the parent catechins. The contribution of catechin derived metabolites/catabolites to the biological effects associated with green tea is yet to be defined. A limited number of chemoprevention trials of green tea or green tea catechins have been conducted to date and have observed potential preventive activity for oral, prostate, and colorectal cancer. Emerging data from multiple ongoing intervention trials will further contribute to defining the cancer preventive activity of green tea or green tea catechins.

Chow, H-H. Sherry; Hakim, Iman A.

2011-01-01

249

Alterations in gene expression of proprotein convertases in human lung cancer have a limited number of scenarios.  

PubMed

Proprotein convertases (PCs) is a protein family which includes nine highly specific subtilisin-like serine endopeptidases in mammals. The system of PCs is involved in carcinogenesis and levels of PC mRNAs alter in cancer, which suggests expression status of PCs as a possible marker for cancer typing and prognosis. The goal of this work was to assess the information value of expression profiling of PC genes. Quantitative polymerase chain reaction was used for the first time to analyze mRNA levels of all PC genes as well as matrix metalloproteinase genes MMP2 and MMP14, which are substrates of PCs, in 30 matched pairs of samples of human lung cancer tumor and adjacent tissues without pathology. Significant changes in the expression of PCs have been revealed in tumor tissues: increased FURIN mRNA level (p<0.00005) and decreased mRNA levels of PCSK2 (p<0.007), PCSK5 (p<0.0002), PCSK7 (p<0.002), PCSK9 (p<0.00008), and MBTPS1 (p<0.00004) as well as a tendency to increase in the level of PCSK1 mRNA. Four distinct groups of samples have been identified by cluster analysis of the expression patterns of PC genes in tumor vs. normal tissue. Three of these groups covering 80% of samples feature a strong elevation in the expression of a single gene in cancer: FURIN, PCSK1, or PCSK6. Thus, the changes in the expression of PC genes have a limited number of scenarios, which may reflect different pathways of tumor development and cryptic features of tumors. This finding allows to consider the mRNAs of PC genes as potentially important tumor markers. PMID:23409034

Demidyuk, Ilya V; Shubin, Andrey V; Gasanov, Eugene V; Kurinov, Alexander M; Demkin, Vladimir V; Vinogradova, Tatyana V; Zinovyeva, Marina V; Sass, Alexander V; Zborovskaya, Irina B; Kostrov, Sergey V

2013-02-07

250

Limitations of widely used high-risk human papillomavirus laboratory-developed testing in cervical cancer screening  

PubMed Central

Objective: To increase awareness of the limitations of high-risk human papillomavirus (hrHPV) laboratory-developed testing (LDT) widely used in US cervical cancer screening. Methods and results: A young woman in her 30s was diagnosed and treated for stage 1B1 cervical squamous cell carcinoma in which HPV 16 DNA was detected using polymerase chain reaction testing. Both 1 month before and 42 months before cervical cancer diagnosis, the patient had highly abnormal cytology findings; however, residual SurePath™ (Becton, Dickson and Company, Franklin Lakes, NJ) vial fluid yielded negative Hybrid Capture 2 (HC2; Qiagen NV, Hilden, Germany) hrHPV LDT results from each of the two specimens. This prompted questions to be asked concerning the performance characteristics of hrHPV LDT. A review of the available data indicates that (1) purification of DNA from SurePath specimens requires complex sample preparation due to formaldehyde crosslinking of proteins and nucleic acids, (2) HC2–SurePath hrHPV testing had not been Food and Drug Administration-approved after multiple premarket approval submissions, (3) detectible hrHPV DNA in the SurePath vial decreases over time, and (4) US laboratories performing HC2–SurePath hrHPV LDT testing are not using a standardized manufacturer-endorsed procedure. Conclusion: Recently updated cervical screening guidelines in the US recommend against the use of hrHPV LDT in cervical screening, including widely used HC2 testing from the SurePath vial. The manufacturer recently issued a technical bulletin specifically warning that use of SurePath samples with the HC2 hrHPV test may provide false negative results and potentially compromise patient safety. Co-collection using a Food and Drug Administration-approved hrHPV test medium is recommended for HPV testing of patients undergoing cervical screening using SurePath samples.

Naryshkin, Sonya; Austin, R Marshall

2012-01-01

251

Permeability of human red cells to a homologous series of aliphatic alcohols. Limitations of the continuous flow-tube method  

PubMed Central

Human red cell permeability to the homologous series of methanol, ethanol, n-propanol, n-butanol, and n-hexanol was determined in tracer efflux experiments by the continuous flow tube method, whose time resolution is 2-3 ms. Control experiments showed that unstirred layers in the cell suspension were less than 2 X 10(-4) cm, and that permeabilities less than or equal to 10(-2) cm s-1 can be determined with the method. Alcohol permeability varied with the chain length (25 degrees C): Pmeth 3.7 X 10(-3) cm s-1, Peth 2.1 X 10(-3) cm s-1, Pprop 6.5 X 10(-3) cm s-1, Pbut less than or equal to 61 X 10(-3) cm s-1, Phex 8.7 X 10(-3) cm s-1. The permeability for methanol, ethanol, and n- propanol was concentration independent (1-500 mM). The permeability to n-butanol and n-hexanol, however, increased above the upper limit of determination at alcohol concentrations of 100 and 25 mM, respectively. The activation energies for the permeability to methanol, n-propanol, and n-hexanol were similar, 50-63 kJ mol-1. Methanol permeability was not reduced by p-chloromercuribenzene sulfonate (PCMBS), thiourea, or phloretin, which inhibit transport of water or hydrophilic nonelectrolytes. It is concluded (a) that all the alcohols predominantly permeate the membrane lipid bilayer structure; (b) that both the distribution coefficient and the diffusion coefficient of the alcohols within the membrane determine the permeability, and (c) that the relative importance of the two factors varies with changes in the chain length.

1983-01-01

252

Global proficiency study of human papillomavirus genotyping.  

PubMed

Internationally comparable quality assurance of Human Papillomavirus (HPV) DNA detection and typing methods is essential for evaluation of HPV vaccines and effective monitoring and implementation of HPV vaccination programs. Therefore, the World Health Organization (WHO) HPV Laboratory Network (LabNet) designed an international proficiency study. Following announcement at the WHO website, the responding laboratories performed HPV typing using one or more of their usual assays on 43 coded samples composed of titration series of purified plasmids of 16 HPV types (HPV6, -11, -16, -18, -31, -33, -35, -39, -45, -51, -52, -56, -58, -59, -66, and -68). Detection of at least 50 IU of HPV16 or HPV18 DNA and of 500 genome equivalents (GE) of the other 14 HPV types (in samples with single and multiple HPV types) was considered proficient. Fifty-four laboratories worldwide submitted a total of 84 data sets. More than 21 HPV-genotyping assays were used. Commonly used methods were Linear Array, Lineblot, InnoLiPa, Clinical Array, type-specific real-time PCR, PCR-Luminex and microarray assays. The major oncogenic HPV types (HPV16 and -18) were detected in 89.7% (70/78) and 92.2% (71/77) of the data sets, respectively. HPV types 56, 59, and 68 were the least commonly detected types (in less than 80% of the data sets). Twenty-eight data sets reported multiple false-positive results and were considered nonproficient. In conclusion, we found that international proficiency studies, traceable to international standards, allow standardized quality assurance for different HPV-typing assays and enable the comparison of data generated from different laboratories worldwide. PMID:20844222

Eklund, Carina; Zhou, Tiequn; Dillner, Joakim

2010-09-15

253

Global Proficiency Study of Human Papillomavirus Genotyping ?  

PubMed Central

Internationally comparable quality assurance of Human Papillomavirus (HPV) DNA detection and typing methods is essential for evaluation of HPV vaccines and effective monitoring and implementation of HPV vaccination programs. Therefore, the World Health Organization (WHO) HPV Laboratory Network (LabNet) designed an international proficiency study. Following announcement at the WHO website, the responding laboratories performed HPV typing using one or more of their usual assays on 43 coded samples composed of titration series of purified plasmids of 16 HPV types (HPV6, -11, -16, -18, -31, -33, -35, -39, -45, -51, -52, -56, -58, -59, -66, and -68). Detection of at least 50 IU of HPV16 or HPV18 DNA and of 500 genome equivalents (GE) of the other 14 HPV types (in samples with single and multiple HPV types) was considered proficient. Fifty-four laboratories worldwide submitted a total of 84 data sets. More than 21 HPV-genotyping assays were used. Commonly used methods were Linear Array, Lineblot, InnoLiPa, Clinical Array, type-specific real-time PCR, PCR-Luminex and microarray assays. The major oncogenic HPV types (HPV16 and -18) were detected in 89.7% (70/78) and 92.2% (71/77) of the data sets, respectively. HPV types 56, 59, and 68 were the least commonly detected types (in less than 80% of the data sets). Twenty-eight data sets reported multiple false-positive results and were considered nonproficient. In conclusion, we found that international proficiency studies, traceable to international standards, allow standardized quality assurance for different HPV-typing assays and enable the comparison of data generated from different laboratories worldwide.

Eklund, Carina; Zhou, Tiequn; Dillner, Joakim

2010-01-01

254

Studies of [ital WW] and [ital WZ] production and limits on anomalous [ital WW[gamma  

SciTech Connect

Evidence of anomalous WW and WZ production was sought in p[bar p] collisions at a center-of-mass energy of [radical] (s) =1.8 hthinsp;TeV. The final states WW(WZ)[r arrow][mu][nu] jet jet+X, WZ[r arrow][mu][nu]ee+X and WZ[r arrow]e[nu]ee+X were studied using a data sample corresponding to an integrated luminosity of approximately 90 hthinsp;pb[sup [minus]1]. No evidence of anomalous diboson production was found. Limits were set on anomalous WW[gamma] and WWZ couplings and were combined with our previous results. The combined 95[percent] confidence level anomalous coupling limits for [Lambda]=2 hthinsp;TeV are [minus]0.25[le][Delta][kappa][le]0.39 ([lambda]=0) and [minus]0.18[le][lambda][le]0.19 ([Delta][kappa]=0), assuming the WW[gamma] couplings are equal to the WWZ couplings. [copyright] [ital 1999] [ital The American Physical Society

Grinstein, S.; Mostafa, M.; Piegaia, R. (Universidad de Buenos Aires, Buenos Aires (Argentina)); Alves, G.A.; Carvalho, W.; da Motta, H.; Santoro, A. (LAFEX, Centro Brasileiro de Pesquisas Fisicas, Rio de Janeiro (Brazil)); Lima, J.G.; Oguri, V. (Universidade do Estado do Rio de Janeiro, Rio de Janeiro (Brazil)); Mao, H.S. (Inst. of High Energy Physics, Beijing, Peoples Republic of (China)); Gomez, B.; Mooney, P.; Negret, J.P. (Universidad de los Andes, Bogota (Colombia)); Hoeneisen, B. (Universidad San Francisco de Quito, Quito (Ecuador)); Parua, N. (Institut des Sciences Nucleaires, IN2P3-CNRS, Universite de Grenoble 1, Grenoble (France)); Ducros, Y. (DAPNIA/Service de Physique des Particules, CEA, Saclay (France)); Beri, S.B.; Bhatnagar, V.; Kohli, J.M.; Singh, J.B. (Panjab Unv., Chandigarh (India)); Shivpuri, R.K. (Delhi Unv., Delhi (India)); Acharya, B.S.; Banerjee, S.; Dugad, S.R.; Gupta, A.; Krishnaswamy, M.R.; Mondal, N.K.; Narasimham, V.S.; Shankar, H.C. (Tata Inst.

1999-10-01

255

A Practical Study of the 66kV Fault Current Limiter (FCL) System with Rectifier  

NASA Astrophysics Data System (ADS)

A fault current limiter (FCL) is extensively expected to suppress fault current, particularly required for trunk power systems heavily connected high-voltage transmission lines, such as 500kV class power system which constitutes the nucleus of the electric power system. By installing such FCL in the power system, the system interconnection is possible without the need to raise the capacity of the circuit breakers, and facilities can be configured for efficiency, among other benefits. For these reasons, fault current limiters based on various principles of operation have been developed both in Japan and abroad. In this paper, we have proposed a new type of FCL system, consisting of solid-state diodes, DC coil and bypass AC coil, and described the specification of distribution power system and 66kV model at the island power system and the superconducting cable power system. Also we have made a practical study of 66kV class, which is the testing items and the future subjects of the rectifier type FCL system.

Tokuda, Noriaki; Matsubara, Yoshio; Yuguchi, Kyosuke; Ohkuma, Takeshi; Hobara, Natsuro; Takahashi, Yoshihisa

256

Hydrostatic limits of Fluorinert liquids used for neutron and transport studies at high pressure  

Microsoft Academic Search

We determined the hydrostatic limits at room temperature for a number of Fluorinert liquids: FC70, FC75, FC77, FC84, FC87 and their mixtures. Pressure exceeding this limit produces pressure gradients in the sample, which are retained at low temperature. The maximum hydrostatic limit (2.3GPa) was found for a (1:1) mixture of FC84\\/87.

V A Sidorov; R A Sadykov

2005-01-01

257

Comparative Study of Transformer Type Superconducting Fault Current Limiters Considering Magnetic Saturation of Iron Core  

Microsoft Academic Search

The paper reports on the transient performances of the transformer type superconducting fault current limiter (SCFCL). This type of fault current limiters (FCL) consists of a transformer in series with the transmission line and a superconducting current limiting device connected to the transformer. The performances are analysed through simulation during a short-circuit fault in the presence and absence of the

T. Kataoka; H. Yamaguchi

2006-01-01

258

Comparative Study of Transformer-Type Superconducting Fault Current Limiters Considering Magnetic Saturation of Iron Core  

Microsoft Academic Search

A transformer-type superconducting fault current limiter (SCFCL) is one of the fault current limiters which have been proposed to reduce the fault currents in power transmission lines. For this type of fault current limiter, a circuit configuration with a shunt inductor is possible to divert the fault current. In this paper, the transient performances of the transformer-type SCFCLs with and

Teruo Kataoka; Hiroshi Yamaguchi

2006-01-01

259

Rabbit as a Model for the Study of Human Diseases  

Microsoft Academic Search

Although genetically modified mice are playing an essential role in the study of the expression and functions of individual\\u000a genes, rabbits are useful animal models to extrapolate animal studies to humans. It is necessary that key gene expression\\u000a and function are equivalent and close to human rather than the outward features or phenotype. For example, to study human\\u000a hypercholesterolemia, the

Masashi Shiomi

260

A Quantitative Analysis of Rate-limiting Steps in the Metastatic Cascade Using Human-specific Real-Time Polymerase Chain Reaction1  

Microsoft Academic Search

A quantitative assessment of rate-limiting steps in metastasis has al- ways been challenging because of the difficulty of detecting small tumor cell populations. We have developed a highly sensitive assay for monitor- ing the metastatic dissemination of human tumor cells in the chick embryo and used this assay to investigate the relative efficacy of sequential stages in the metastatic cascade

Andries Zijlstra; Rebecca Mellor; Giano Panzarella; Ronald T. Aimes; John D. Hooper; Natalia D. Marchenko; James P. Quigley

2002-01-01

261

The experiment study on infrared radiation spectrum of human body  

Microsoft Academic Search

Infrared thermography is a non-contact measurement method which is widely used in human body temperature monitoring. But there are still some limitations when infrared thermography is used in medical diagnosis, so the accuracy of infrared thermal imaging is still being debated. Spectroscopic analysis is a powerful technology. It not only can reflect the relative temperature difference accurately, but also can

W. L. Yu; Zhen. Wang; Lei Jin

2012-01-01

262

Comparative study of the extracellular proteome of Sulfolobus species reveals limited secretion.  

PubMed

Although a large number of potentially secreted proteins can be predicted on the basis of genomic distribution of signal sequence-bearing proteins, protein secretion in Archaea has barely been studied. A proteomic inventory and comparison of the growth medium proteins in three hyperthermoacidophiles, i.e., Sulfolobus solfataricus, S. acidocaldarius and S. tokodaii, indicates that only few proteins are freely secreted into the growth medium and that the majority originates from cell envelope bound forms. In S. acidocaldarius both cell-associated and secreted alpha-amylase activities are detected. Inactivation of the amyA gene resulted in a complete loss of activity, suggesting that the same protein is responsible for the a-amylase activity at both locations. It is concluded that protein secretion in Sulfolobus is a limited process, and it is suggested that the S-layer may act as a barrier for the free diffusion of folded proteins into the medium. PMID:19957093

Ellen, Albert F; Albers, Sonja-Verena; Driessen, Arnold J M

2009-12-02

263

Potential and limitations of multidecadal satellite soil moisture observations for selected climate model evaluation studies  

NASA Astrophysics Data System (ADS)

Soil moisture is an essential climate variable (ECV) of major importance for land-atmosphere interactions and global hydrology. An appropriate representation of soil moisture dynamics in global climate models is therefore important. Recently, a first multidecadal, observation-based soil moisture dataset has become available that provides information on soil moisture dynamics from satellite observations (ECVSM, essential climate variable soil moisture). The present study investigates the potential and limitations of this new dataset for several applications in climate model evaluation. We compare soil moisture data from satellite observations, reanalysis and simulations from a state-of-the-art land surface model and analyze relationships between soil moisture and precipitation anomalies in the different dataset. Other potential applications like model parameter optimization or model initialization are not investigated in the present study. In a detailed regional study, we show that ECVSM is capable to capture well the interannual and intraannual soil moisture and precipitation dynamics in the Sahelian region. Current deficits of the new dataset are critically discussed and summarized at the end of the paper to provide guidance for an appropriate usage of the ECVSM dataset for climate studies.

Loew, A.; Stacke, T.; Dorigo, W.; de Jeu, R.; Hagemann, S.

2013-09-01

264

Third order optical nonlinearity and optical limiting studies of propane hydrazides  

NASA Astrophysics Data System (ADS)

Four hydrazones, 2-(4-isobutylphenyl)-N?-[phenylmethylene] propanehydrazide (P1), 2-(4-isobutylphenyl)-N?-[(4- tolyl)methylene] propane hydrazide (P2), 2-(4-isobutylphenyl)-N?-[1-(4- chlorophenyl)ethylidene] propanehydrazide (P3) and 2-(4-isobutylphenyl)-N?-[1-(4-Nitrrophenyl)ethylidene] propane hydrazide (P4) were synthesized and their third order nonlinear optical properties have been investigated using a single beam Z-scan technique with nanosecond laser pulses at 532 nm. The measurement on the compound-P1 is not reported as there is no detectable nonlinear response. Open aperture data of the other three compounds indicate two photon absorption at this wavelength. The nonlinear refractive index n2, nonlinear absorption coefficient ?, magnitude of effective third order susceptibility ?(3), the second order hyperpolarizability ?h and the coupling factor ? have been estimated. The values obtained are comparable with the values obtained for 4-methoxy chalcone derivatives and dibenzylideneacetone derivatives. The experimentally determined values of ?, n2, Re ?(3) and Im ?(3), ?h and ? of the compound-P4 are 1.42 cm/GW, -0.619 × 10-11 esu, -0.663 × 10-13 esu, 0.22 × 10-13 esu, 0.34 × 10-32 esu and 0.33 respectively. Further the compound-P4 exhibited the best optical power limiting behavior at 532 nm among the compounds studied. Our studies suggest that compounds P2, P3 and P4 are potential candidates for the optical device applications such as optical limiters and optical switches.

Naseema, K.; Manjunatha, K. B.; Sujith, K. V.; Umesh, G.; Kalluraya, Balakrishna; Rao, Vijayalakshmi

2012-09-01

265

A Histopathological Study On Human Cysticercosis.  

PubMed

A study was made on 258 cases of cysticercosis, that were examined and diagnosed at the Department of Pathology, College of Medicine, Seoul National University during a period of 9 years from 1968 to 1976 inclusive. There were a total of 35,363 surgical specimens examined during the same period, thus revealing the relative frequency ratio of cysticercosis among surgical accessions to be 0.73%. The common sites of involvement of cysticercosis were skeletal muscle, subcutaneous tissue, breast, brain and eye in decreasing order of frequency. Painless palpable nodules were the most common initial presentation clinically. Histopathological staging was attempted based on the host tissue reaction and worm morphology. It was arbitrarily classified into early, intermediate and late stages. In general the morphology of the parasite consisted of a well preserved and compact calcospherules with intact subcuticular muscle layer in the early stage, showing a progressive deterioration of parasitic structures, finally undergoing resorptive process or mummification. The host tissue reation in the early stage was characterized by a diffuse epithelioid cell proliferation with lymphocytic and eosinophilic infiltration without capsule formation. The intermediate stage consisted of a diffuse histiocytic proliferation with well formed outer collagen capsule. The latestage revealed mostly thinned out, well collagenized capsule with scanty lymphocytic infiltration. The parasite in the well formed cyst as usually distorted and often mummified. But the hooklets were relatively preserved up to the late stage. These finding suggest that the host tissue reacts to the cysticercus worm in fairly uniform fashion, and this fashion appears to have a sequence, i.e., violent lymphohistiocytic response in the initial phase of infection, and undergoing a gradual fibrotic (encapsulating) self-limiting course, finally being stabilized by a dense, acelluar collagen capsule or collapse and absorption. PMID:12902773

Chi, Hyun Sook; Chi, Je Geun

1978-12-01

266

Teacher Leader Human Relations Skills: A Comparative Study  

ERIC Educational Resources Information Center

|In this study, 142 graduate school teachers working in schools throughout southwestern Ohio assessed their human relation skills. A human relations survey was used for the study, and results were compared with colleagues assessing the teachers in the study. The survey was developed using a Likert-type scale, and was based on key elements…

Roby, Douglas E.

2012-01-01

267

Chamber studies of SOA formation from aromatic hydrocarbons: observation of limited glyoxal uptake  

NASA Astrophysics Data System (ADS)

This study evaluates the significance of glyoxal acting as an intermediate species leading to secondary organic aerosol (SOA) formation from aromatic hydrocarbon photooxidation under humid conditions. Rapid SOA formation from glyoxal uptake onto aqueous (NH4)2SO4 seed particles is observed in agreement with previous studies; however, glyoxal did not partition significantly to SOA (with or without aqueous seed) during aromatic hydrocarbon photooxidation within an environmental chamber (RH less than 80%). Rather, glyoxal influences SOA formation by raising hydroxyl (OH) radical concentrations. Four experimental approaches supporting this conclusion are presented in this paper: (1) increased SOA formation and decreased SOA volatility in the toluene + NOx photooxidation system with additional glyoxal was reproduced by matching OH radical concentrations through H2O2 addition; (2) glyoxal addition to SOA seed formed from toluene + NOx photooxidation did not increase SOA volume under dark; (3) SOA formation from toluene + NOx photooxidation with and without deliquesced (NH4)2SO4 seed resulted in similar SOA growth, consistent with a minor contribution from glyoxal uptake onto deliquesced seed and organic coatings; and (4) the fraction of a C4H9+ fragment (observed by Aerodyne High Resolution Time-of-Flight Aerosol Mass Spectrometer, HR-ToF-AMS) in SOA from 2-tert-butylphenol (BP) oxidation was unchanged in the presence of additional glyoxal despite enhanced SOA formation. This study suggests that glyoxal uptake onto aerosol during the oxidation of aromatic hydrocarbons is more limited than previously thought.

Nakao, S.; Liu, Y.; Tang, P.; Chen, C.-L.; Zhang, J.; Cocker, D. R., III

2012-05-01

268

Multilocus Genotyping of Human Giardia Isolates Suggests Limited Zoonotic Transmission and Association between Assemblage B and Flatulence in Children  

Microsoft Academic Search

BackgroundGiardia intestinalis is one of the most common diarrhea-related parasites in humans, where infection ranges from asymptomatic to acute or chronic disease. G. intestinalis consists of eight genetically distinct genotypes or assemblages, designated A–H, and assemblages A and B can infect humans. Giardiasis has been classified as a possible zoonotic disease but the role of animals in human disease transmission

Marianne Lebbad; Ingvor Petersson; Lillemor Karlsson; Silvia Botero-Kleiven; Jan O. Andersson; Bo Svenungsson; Staffan G. Svärd

2011-01-01

269

Radium in humans: A review of U.S. studies  

SciTech Connect

This document was originally conceived as a compilation of activities at Argonne National Laboratory that were directed toward the study of radium in humans. However, it soon became obvious that this was a very limited approach, because such a compilation would include no background on the widespread uses of radium in industry and in the medical profession, nor would it address the early history of the discovery of the hazards of radium. Such an approach would also ignore contributions to the study of radium effects made at other laboratories. This document now addresses these topics, in order to give an overall picture of what might be called the radium era, that period from the early part of this century, when radium was rapidly exploited as a tool and a medication, to the present time, when radium is not generally used and the study of its effects has been terminated. The appendix to this review lists all of the measured radium cases, a total of 2,403 individuals whose records were in the files at the end of 1990. For each case the route of exposure, the dates of exposure, the years of birth and death, the measured body content, the calculated intake and dose, and the cause of death have been listed. 165 refs.

Rowland, R.E.

1994-09-01

270

Twins for epigenetic studies of human aging and development.  

PubMed

Most of the complex traits including aging phenotypes are caused by the interaction between genome and environmental conditions and the interface of epigenetics may be a central mechanism. Although modern technologies allow us high-throughput profiling of epigenetic patterns already at genome level, our understanding of genetic and environmental influences on the epigenetic processes remains limited. Twins are of special interest for genetic studies due to their genetic similarity and rearing-environment sharing. The classical twin design has made a great contribution in dissecting the genetic and environmental contributions to human diseases and complex traits. In the era of functional genomics, the valuable sample of twins is helping to bridge the gap between gene activity and the environments through epigenetic mechanisms unlimited by DNA sequence variations. We propose to extend the classical twin design to study the aging-related molecular epigenetic phenotypes and link them with environmental exposures especially early life events. Different study designs and application issues will be highlighted and novel approaches introduced with aim at making uses of twins in assessing the environmental impact on epigenetic changes during development and in the aging process. PMID:22750314

Tan, Qihua; Christiansen, Lene; Thomassen, Mads; Kruse, Torben A; Christensen, Kaare

2012-06-29

271

Fourier transform Raman spectroscopic studies of human and animal skins  

NASA Astrophysics Data System (ADS)

The stratum corneum is the outermost layer of the skin and provides the principal barrier for the ingress of chemicals and environmental toxins into human and animal tissues. However, human skin has several advantages for the administration of therapeutic agents (transdermal drug delivery), but problems occur with the supply, storage, and biohazardous nature of human tissue. Hence, alternative animal tissues have been prepared to model drug diffusion across human skin but the molecular basis for comparison is lacking. Here, FT-Raman spectra of mammalian (human and pig) and reptilian (snake) skins have been obtained and the structural dissimilarities are correlated with drug diffusion studies across the tissues.

Barry, Brian W.; Edwards, Howell G.; Williams, Adrian C.

1994-01-01

272

A unified study on human and Web granular reasoning  

Microsoft Academic Search

In this talk, we will describe studying on granular reasoning of human and Web in a unified way from the viewpoint of brain informatics. We consider Web granular reasoning as an application of human-inspired granular reasoning. As for human granular reasoning, based on the previous studies about basic-level advantage and its reversal effect, we use fMRI\\/ERP to investigate how the

Ning Zhong

2009-01-01

273

Risk assessment of diesel exhaust and lung cancer: combining human and animal studies after adjustment for biases in epidemiological studies  

PubMed Central

Background Risk assessment requires dose-response data for the evaluation of the relationship between exposure to an environmental stressor and the probability of developing an adverse health effect. Information from human studies is usually limited and additional results from animal studies are often needed for the assessment of risks in humans. Combination of risk estimates requires an assessment and correction of the important biases in the two types of studies. In this paper we aim to illustrate a quantitative approach to combining data from human and animal studies after adjusting for bias in human studies. For our purpose we use the example of the association between exposure to diesel exhaust and occurrence of lung cancer. Methods Firstly, we identify and adjust for the main sources of systematic error in selected human studies of the association between occupational exposure to diesel exhaust and occurrence of lung cancer. Evidence from selected animal studies is also accounted for by extrapolating to average ambient, occupational exposure concentrations of diesel exhaust. In a second stage, the bias adjusted effect estimates are combined in a common effect measure through meta-analysis. Results The random-effects pooled estimate (RR) for exposure to diesel exhaust vs. non-exposure was found 1.37 (95% C.I.: 1.08-1.65) in animal studies and 1.59 (95% C.I.: 1.09-2.10) in human studies, whilst the overall was found equal to 1.49 (95% C.I.: 1.21-1.78) with a greater contribution from human studies. Without bias adjustment in human studies, the pooled effect estimate was 1.59 (95% C.I.: 1.28-1.89). Conclusions Adjustment for the main sources of uncertainty produced lower risk estimates showing that ignoring bias leads to risk estimates potentially biased upwards.

2011-01-01

274

An epidemiologic study of the human bite.  

PubMed Central

The 892 human bites reported to the New York City Department of Health in 1977 were analyzed by time, place, and the victim's characteristics. The bites appeared to have a seasonality, increasing in March and exceeding the mean monthly average through August. The bite rate for the entire city, 10.7 per 100,000 population, was exceeded in 5 of the 10 Brooklyn health districts; one of these districts reported a rate of 60.9 human bites per 100,000 population. Most of the bites with identifiable locations occurred indoors (63.2 percent). In 72.8 percent of the bite episodes in which the activities surrounding them were known, these activities were aggressive in nature. Males exceeded females as bite victims in all age groups except those 10-20 and 55-60 years. Bites of the upper extremity accounted for 61.2 percent of the total bites. Left-sided bites exceeded right-sided, except for the hand. In frequency of reported occurrence, the human bite ranks third, after the dog bite and the cat bite. Human bites may be a useful indicator of antisocial behavior.

Marr, J S; Beck, A M; Lugo, J A

1979-01-01

275

Human Fetal Behavior: 100 Years of Study.  

ERIC Educational Resources Information Center

|Reviews literature on human fetal behavior. Includes descriptions of coupling of body movements and fetal heart rate and behavior maturation from conception to term. Discusses use of stimulus-induced behavior to examine sensory and cognitive development, and spontaneous and stimulus-induced behavior to assess fetal well-being. Notes research…

Kisilevsky, B. S.; Low, J. A.

1998-01-01

276

Human Fetal Behavior: 100 Years of Study  

Microsoft Academic Search

The literature on spontaneous and stimulus induced human, fetal behaviour is reviewed. Spontaneous fetal behaviours, including body movements, fetal heart rate, coupling of body movements and fetal heart rate, breathing, and the association among behaviours have been characterized. In addition, maturation of behaviours have been described from conception to term. Stimulus induced behaviour, in particular fetal heart rate changes and

B. S. Kisilevsky; J. A. Low

1998-01-01

277

Human Services Study. Report on Substance Abuse.  

National Technical Information Service (NTIS)

Substance abuse is examined as one component of the countywide human service planning program of the Johnson County Regional Planning Commission in Iowa. The report on substance abuse is one in a series of eight reports describing the program. The overall...

1977-01-01

278

Human Services Study. Report on Mental Health.  

National Technical Information Service (NTIS)

The mental health component of the countywide human services planning program of the Johnson County Regional Planning Commission in Iowa is described. The report on mental health is one in a series of eight reports outlining the program. The overall goal ...

1977-01-01

279

Analysis of human brain exposure to low-frequency magnetic fields: a numerical assessment of spatially averaged electric fields and exposure limits.  

PubMed

Compliance with the established exposure limits for the electric field (E-field) induced in the human brain due to low-frequency magnetic field (B-field) induction is demonstrated by numerical dosimetry. The objective of this study is to investigate the dependency of dosimetric compliance assessments on the applied methodology and segmentations. The dependency of the discretization uncertainty (i.e., staircasing and field singularity) on the spatially averaged peak E-field values is first determined using canonical and anatomical models. Because spatial averaging with a grid size of 0.5?mm or smaller sufficiently reduces the impact of artifacts regardless of tissue size, it is a superior approach to other proposed methods such as the 99th percentile or smearing of conductivity contrast. Through a canonical model, it is demonstrated that under the same uniform B-field exposure condition, the peak spatially averaged E-fields in a heterogeneous model can be significantly underestimated by a homogeneous model. The frequency scaling technique is found to introduce substantial error if the relative change in tissue conductivity is significant in the investigated frequency range. Lastly, the peak induced E-fields in the brain tissues of five high-resolution anatomically realistic models exposed to a uniform B-field at ICNIRP and IEEE reference levels in the frequency range of 10?Hz to 100?kHz show that the reference levels are not always compliant with the basic restrictions. Based on the results of this study, a revision is recommended for the guidelines/standards to achieve technically sound exposure limits that can be applied without ambiguity. PMID:23404214

Chen, Xi-Lin; Benkler, Stefan; Chavannes, Nicholas; De Santis, Valerio; Bakker, Jurriaan; van Rhoon, Gerard; Mosig, Juan; Kuster, Niels

2013-02-12

280

Program for Persons of Limited English-Speaking Ability (PLESA): Case Study No. 7. Honolulu, Hawaii: Developing Bilingual Vocational Curricula.  

National Technical Information Service (NTIS)

Through the Program for Persons of Limited English-Speaking Ability (PLESA), 47 prime sponsors provided training and employment assistance to more than 6,000 persons of limited English-speaking ability. These case studies are part of the Department of Lab...

J. Reynolds TinMyaingThein

1978-01-01

281

Study of the Lithium Deposition Profile on the TFTR Inner Bumper Limiter in Discharges with Li-Pellet Injection  

Microsoft Academic Search

Significant improvements in supershot confinement have been achieved with wall conditioning by Li pellet injection. However the mechanism producing the improvement has yet to be demonstrated. To help guide models for understanding this mechanism, measurements have been made to study the Li-deposition profile on the inner bumper limiter and the relative influxes of Li and C from the limiter. Lithium

K. W. Hill; D. K. Mansfield; M. G. Bell; B. Davis; H. W. Kugel; S. S. Medley; A. T. Ramsey; C. H. Skinner; J. D. Strachan; C. E. Bush; J. Hogan; G. A. Wurden; W. Tighe

1996-01-01

282

No monkey business: why studying NK cells in non-human primates pays off  

PubMed Central

Human NK (hNK) cells play a key role in mediating host immune responses against various infectious diseases. For practical reasons, the majority of the data on hNK cells has been generated using peripheral blood lymphocytes. In contrast, our knowledge of NK cells in human tissues is limited, and not much is known about developmental pathways of hNK cell subpopulations in vivo. Although research in mice has elucidated a number of fundamental features of NK cell biology, mouse, and hNK cells significantly differ in their subpopulations, functions, and receptor repertoires. Thus, there is a need for a model that is more closely related to humans and yet allows experimental manipulations. Non-human primate models offer numerous opportunities for the study of NK cells, including the study of the role of NK cells after solid organ and stem cell transplantation, as well as in acute viral infection. Macaque NK cells can be depleted in vivo or adoptively transferred in an autologous system. All of these studies are either difficult or unethical to carry out in humans. Here we highlight recent advances in rhesus NK cell research and their parallels in humans. Using high-throughput transcriptional profiling, we demonstrate that the human CD56bright and CD56dim NK cell subsets have phenotypically and functionally analogous counterparts in rhesus macaques. Thus, the use of non-human primate models offers the potential to substantially advance hNK cell research.

Hong, Henoch S.; Rajakumar, Premeela A.; Billingsley, James M.; Reeves, R. Keith; Johnson, R. Paul

2012-01-01

283

The Human First Trimester Gestational Sac Limits Rather than Facilitates Oxygen Transfer to the Foetus—A Review  

Microsoft Academic Search

Oxygen (O2) free radicals are a potential teratologic threat to the foetal tissues and are known to be involved in the pathophysiology of common human pregnancy disorders such as miscarriage and pre-eclampsia. During the first two months of human gestation, the placenta surrounds the whole gestational sac, the villi contain only a few capillaries located mainly within the centre of

E. Jauniaux; B. Gulbis; G. J. Burton

2003-01-01

284

Benefit-sharing: an inquiry regarding the meaning and limits of the concept in human genetic research  

Microsoft Academic Search

The Human Genome Project and the related research and development activities have raised heated discussions around some very basic ethical and social issues. A much debated concern is that of justice in human genetic research and in possible applications, especially pertaining to questions of just benefit-sharing - who and based on what sort of argumentation has the right to require

KADRI SIMM

285

A study on DC hybrid three-phase fault current limiting interrupter for a power distribution system  

NASA Astrophysics Data System (ADS)

For the purpose of protecting electric power system, many researches and developments of fault current limiters are being performed. The authors studied a dc hybrid three-phase fault current limiting interrupter (FCLI) composed of a superconducting reactor and an S/N transition element, connected in series each other. The dc hybrid type fault current limiting interrupter can limit a fault current by means of the inductance of high temperature superconducting (HTS) coil together with the normal transition of HTS bulk material (HTSB). In the case of an accident, the normal transition of the bulk material can be accelerated by the magnetic field of the HTS coil. In this paper, the dc hybrid type fault current limiting interrupter for 5.5 km long 6.6 kV 600 A power distribution system is analyzed, and performances of fault current limitation and interruption are confirmed. Moreover, a reclosing operation is discussed for this power distribution system.

Shao, Hongtian; Satoh, Tomoyuki; Yamaguchi, Mitsugi; Fukui, Satoshi; Ogawa, Jun; Satoh, Takao; Ishikawa, Hiroyuki

2005-10-01

286

A Hubble Space Telescope Study of Lyman Limit Systems: Census and Evolution  

Microsoft Academic Search

We present a survey for optically thick Lyman limit absorbers at z < 2.6 using archival Hubble Space Telescope observations with the Faint Object Spectrograph and Space Telescope Imaging Spectrograph. We identify 206 Lyman limit systems (LLSs), increasing the number of cataloged LLSs at z < 2.6 by a factor of ~10. We compile a statistical sample of 50 tauLLS

Joseph Ribaudo; Nicolas Lehner; J. Christopher Howk

2011-01-01

287

Limits on quark-lepton compositeness and studies of W asymmetry at the Tevatron collider  

SciTech Connect

Drell-Yan dilepton production at high invariant mass place strong limits on quark substructure. Compositeness limits from CDF Run 1, and expected sensitivity in Run II and TEV33 are presented. The W asymmetry data constrains the slope of the d/u quark distributions and significantly reduces the systematic error on the extracted value of the W mass.

Bodek, A.

1996-10-01

288

A study on diffraction efficiency of an adaptive optical limiter based on nonlinear medium sandwiched structure  

NASA Astrophysics Data System (ADS)

An adaptive optical limiter composed of nonlinear medium sandwiched between phase grating and one piece of slab is discussed under the circumstances of weak lights and intense laser pulses. The effects of refractive indices mismatch between phase grating and nonlinear medium on diffraction efficiency are investigated, which provides guidance for compounding nonlinear medium and evaluating limiting performance.

Wang, H. J.; Yu, Y. B.; Zhao, J. W.; Ji, F. M.; Wang, Y. J.; Yin, Z.

2013-10-01

289

A theoretical and experimental study on forming limit diagram for a seamed tube hydroforming  

Microsoft Academic Search

The purpose of this work is to establish the forming limit diagram (FLD) for a seamed tube hydroforming. A new theoretical model is developed to predict the FLD for a seamed tube hydroforming. Based on this theoretical model, the FLD for a seamed tube made of QSTE340 sheet metal is calculated by using the Hosford yield criterion. Some forming limit

Xianfeng Chen; Zhongqi Yu; Bo Hou; Shuhui Li; Zhongqin Lin

2011-01-01

290

A study of two-dimensional array transducers for limited diffraction beams  

Microsoft Academic Search

The newly developed limited diffraction beams such as the Bessel beams and X waves have a large depth of field and approximate depth-independent property. They have possible applications in medical imaging, color Doppler imaging, tissue characterization, and nondestructive evaluation of materials, and in other wave related physical branches such as electromagnetics and optics. However, limited diffraction beams are currently produced

Jian-Yu Lu; James F. Greenleaf

1994-01-01

291

Ownership Concentration in the TV Industry A Case Study on the Limitations of Media Policy  

Microsoft Academic Search

The wish to limit ownership concentration in the media industry has been common in the newspaper sector, but hardly very successful. As commercial television was more exten- sively introduced, governments saw possibilities of limiting ownership concentration in this sector. One such case is the Swedish TV4, owned at the start in 1991 by a consortium of financial and smaller publishing

SUNE TJERNSTRÖM

292

A study of rechargeable zinc electrodes for alkaline cells requiring anodic limitation  

Microsoft Academic Search

Problems associated with the cyclic operation of zinc electrodes in rechargeable alkaline cells for which anodic limitation is required are investigated. Experiments were conducted to determine the influence of electrolyte additives and cell construction on the capacity loss of limited zinc electrodes during cycling; current-voltage diagrams for zinc electrodes within the potential range of passivation and of hydrogen evolution were

L. Binder; W. Odar; K. Kordesch

1981-01-01

293

A computational study of low oxygen flammability limit for thick solid slabs  

Microsoft Academic Search

A preventive approach to fire safety is proper material selection based on the flammability characteristics. One such measure of flammability is the limiting oxygen index (LOI). This is a commonly used numerical flammability index for relative grading and selecting materials. The test measures the extinction limit of a downward spreading flame over a finite size (rectangular slab or rod) fuel

Amit Kumar; James S. T'ien

2006-01-01

294

The Ethological Approach to the Study of Human Behavior  

Microsoft Academic Search

Human ethology, which was established on the basis of classical zooethol- ogy, can be an inspirational contribution to the study of human behavior. The study of behavior in natural conditions is stimulating as well as the primary interest of ethologists in such behavioral patterns showing evo- lutionary success and benefi ts and which are called inborn or innate. The extensive

Zdenek Klein

2000-01-01

295

Basic study on avoidance motions for human behaviors  

Microsoft Academic Search

The purpose of this study was propose the algorithm on the system including the mechanism to avoid a man. On basic study, this paper reports on the experiment of human avoidance motion, the experimental system for avoidance motions and experimental results. The human avoidance behavior occurs when passing each other. Many passings each of experimenter and subject have been recorded

M. Yoda; Y. Shiota

1995-01-01

296

Limitations and relative utility of screening assays to assess engineered nanoparticle toxicity in a human cell line  

SciTech Connect

Single-walled carbon nanotubes (SWCNT), fullerenes (C{sub 60}), carbon black (CB), nC{sub 60}, and quantum dots (QD) have been studied in vitro to determine their toxicity in a number of cell types. Here, we report that classical dye-based assays such as MTT and neutral red (NR) that determine cell viability produce invalid results with some NM (nanomaterials) due to NM/dye interactions and/or NM adsorption of the dye/dye products. In this study, human epidermal keratinocytes (HEK) were exposed in vitro to CB, SWCNT, C{sub 60}, nC{sub 60}, and QD to assess viability with calcein AM (CAM), Live/Dead (LD), NR, MTT, Celltiter 96 AQueous One (96 AQ), alamar Blue (aB), Celltiter-Blue (CTB), CytoTox One{sup TM} (CTO), and flow cytometry. In addition, trypan blue (TB) was quantitated by light microscopy. Assay linearity (R{sup 2} value) was determined with HEK plated at concentrations from 0 to 25,000 cells per well in 96-well plates. HEK were treated with serial dilutions of each NM for 24 h and assessed with each of the viability assays. TB, CAM and LD assays, which depend on direct staining of living and/or dead cells, were difficult to interpret due to physical interference of the NM with cells. Results of the dye-based assays varied a great deal, depending on the interactions of the dye/dye product with the carbon nanomaterials (CNM). Results show the optimal high throughput assay for use with carbon and noncarbon NM was 96 AQ. This study shows that, unlike small molecules, CNM interact with assay markers to cause variable results with classical toxicology assays and may not be suitable for assessing nanoparticle cytotoxicity. Therefore, more than one assay may be required when determining nanoparticle toxicity for risk assessment.

Monteiro-Riviere, N.A. [Center for Chemical Toxicology Research and Pharmacokinetics, North Carolina State University, 4700 Hillsborough Street, Raleigh, NC 27606 (United States); Inman, A.O.; Zhang, L.W. [Center for Chemical Toxicology Research and Pharmacokinetics, North Carolina State University, 4700 Hillsborough Street, Raleigh, NC 27606 (United States)

2009-01-15

297

Parasexual approaches to the study of human genetic disease.  

PubMed

We have used two different strategies to construct hybrid cells in which specific, individual human chromosomes or fragments thereof are maintained by direct selective pressure. Our first approach was to introduce a drug-resistance gene into human chromosomes using a retroviral vector, and to transfer the marked chromosomes via microcells into mouse cells. The second method was to fuse gamma-irradiated human cells with rodent cells to produce hybrids containing fragments of the human X chromosome. Such hybrid cell lines should greatly facilitate both human gene mapping and the isolation of human genes by molecular cloning. The gene-transfer technologies described here can also be used to construct cell lines in which the expression of genes involved in human diseases can be studied in vitro. PMID:3551736

Lugo, T G; Leach, R J; Fournier, R E

1986-01-01

298

The Background-Limited Infrared Submillimeter Spectrograph (BLISS) for SPICA: A Design Study  

NASA Astrophysics Data System (ADS)

The far-IR waveband carries half of the photon energy ever produced in galaxies and quasars, evidence of the major role of dust-obscured processes in bringing about the modern Universe. The bulk of this appears to have occurred in the first half of the Universe's history (z>1). We are developing the Background-Limited Infrared-Submillimeter Spectrograph (BLISS) to capitalize on SPICA's cold telescope and provide a breakthrough far-IR spectroscopy capability. BLISS-SPICA is 6 orders of magnitude faster than the spectrometers on Herschel and SOFIA in obtaining full-band spectra, and will observe dust-obscured galaxies at all epochs back to the first billion years after the Big Bang (redshift 6), BLISS-SPICA thus probes the complete history of dust-obscured star formation and black-hole growth. It will also be extremely powerful for studying ice-giant planet formation in protoplanetary disks, with its sensitivity to very small amounts of gas. BLISS covers the 38-433 micron range in five grating-spectrometer bands, with two simultaneous sky positions. The detector package is 4224 silicon-nitride micro-mesh leg-isolated bolometers with superconducting transition-edge-sensed (TES) thermistors, read out with a cryogenic time-domain multiplexer, all cooled to 50mK for optimal sensitivity. All technical elements of BLISS have heritage in mature scientific instruments, and many have flown. We report on our design study in which we are optimizing performance while accommodating SPICA's constraints, including the stringent cryogenic mass budget. We present the science case for BLISS, as well as our progress in all key technical aspects: 1) opto-mechanical instrument architecture, 2) detector and readout approach, and 3) sub-K cooling approach. We thank the NASA for support of the BLISS study.

Bradford, Charles; BLISS-SPICA Study Team

2010-05-01

299

Neural substrates of cognitive capacity limitations  

PubMed Central

Cognition has a severely limited capacity: Adult humans can retain only about four items “in mind”. This limitation is fundamental to human brain function: Individual capacity is highly correlated with intelligence measures and capacity is reduced in neuropsychiatric diseases. Although human capacity limitations are well studied, their mechanisms have not been investigated at the single-neuron level. Simultaneous recordings from monkey parietal and frontal cortex revealed that visual capacity limitations occurred immediately upon stimulus encoding and in a bottom-up manner. Capacity limitations were found to reflect a dual model of working memory. The left and right halves of visual space had independent capacities and thus are discrete resources. However, within each hemifield, neural information about successfully remembered objects was reduced by adding further objects, indicating that resources are shared. Together, these results suggest visual capacity limitation is due to discrete, slot-like, resources, each containing limited pools of neural information that can be divided among objects.

Buschman, Timothy J.; Siegel, Markus; Roy, Jefferson E.; Miller, Earl K.

2011-01-01

300

Studies of ?-protein in human cell cultures  

Microsoft Academic Search

Summary  ?-Protein growth fraction (AGF) eliminates the 60- to 90-day adaptive phase required to establish actively growing cultures\\u000a of HeLa (Gey), human heart (Girardi), KB (Eagle) and other established cell lines in serum-free chemically defined medium\\u000a A3. AGF is effective at less than 0.4 ?g per ml. By using the procedures described in the text, it is possiblee to culture HeLa

Richard Holmes; Gretchen Mercer; Nalini Mohamed

1979-01-01

301

Designing studies of drug conditioning in humans  

Microsoft Academic Search

There has been much recent interest in the possibility that signals for drug use in humans acquire the ability to evoke classically\\u000a conditioned (learned) states which motivate drug taking. Much data now suggest that cues paired with drug use come to elicit\\u000a physiological responses and subjective reports of drug-related feelings like craving and withdrawal. However, the designs\\u000a employed do not

Steven J. Robbins; Ronald N. Ehrman

1992-01-01

302

A comparative study of the trabecular bony architecture of the talus in humans, non-human primates, and Australopithecus.  

PubMed

This study tested the hypothesis that talar trabecular microarchitecture reflects the loading patterns in the primate ankle joint, to determine whether talar trabecular morphology might be useful for inferring locomotor behavior in fossil hominins. Trabecular microarchitecture was quantified in the anteromedial, anterolateral, posteromedial, and posterolateral quadrants of the talar body in humans and non-human primates using micro-computed tomography. Trabecular bone parameters, including bone volume fraction, trabecular number and thickness, and degree of anisotropy differed between primates, but not in a manner entirely consistent with hypotheses derived from locomotor kinematics. Humans have highly organized trabecular struts across the entirety of the talus, consistent with the compressive loads incurred during bipedal walking. Chimpanzees possess a high bone volume fraction, consisting of plate-like trabecular struts. Orangutan tali are filled with a high number of thin, connected trabeculae, particularly in the anterior portion of the talus. Gorillas and baboons have strikingly similar internal architecture of the talus. Intraspecific analyses revealed no regional differences in trabecular architecture unique to bipedal humans. Of the 22 statistically significant regional differences in the human talus, all can also be found in other primates. Trabecular thickness, number, spacing, and connectivity density had the same regional relationship in the talus of humans, chimpanzees, gorillas, and baboons, suggesting a deeply conserved architecture in the primate talus. Australopithecus tali are human-like in most respects, differing most notably in having more oriented struts in the posteromedial quadrant of the body compared with the posterolateral quadrant. Though this result could mean that australopiths loaded their ankles in a unique manner during bipedal gait, the regional variation in degree of anisotropy was similar in humans, chimpanzees, and gorillas. These results collectively suggest that the microarchitecture of the talus does not simply reflect the loading environment, limiting its utility in reconstructing locomotion in fossil primates. PMID:22840715

DeSilva, Jeremy M; Devlin, Maureen J

2012-07-26

303

MEG studies of human vision: Retinotopic organization of V1  

SciTech Connect

A primary goal of noninvasive studies of human vision is to identify and characterize multiple visual areas in the human brain analogous to those identified in studies of nonhuman primates. By combining functional MEG measurements with images of individual anatomy derived from MRI, the authors hope to determine the location and arrangement of multiple visual areas in human cortex and to probe their functional significance. The authors have identified several different visual areas thus far which appear to be topographically organized. This paper focuses on the retinotopic characterization of the primary visual area (V1) in humans.

Aine, C.; George, J.; Ranken, D.; Best, E.; Tiee, W.; Vigil, V.; Flynn, E.; Wood, C. [Los Alamos National Lab., NM (United States); Supek, S. [Zagreb Univ. (Croatia). Dept. of Physics

1993-12-31

304

Effect of thoracic gas compression and bronchodilation on the assessment of expiratory flow limitation during exercise in healthy humans.  

PubMed

Expiratory flow limitation (EFL) during exercise may be overestimated or falsely detected when superimposing tidal breaths within a pre-exercise maximal expiratory flow volume (MEFV) curve due to thoracic gas compression (TGC) and bronchodilation. Accordingly, the purpose of this study was to determine the effects of TGC and bronchodilation on the assessment of EFL in 35 healthy subjects. A pre-exercise forced vital capacity (FVC) maneuver was performed that did not account for TGC (MEFV(pre)). Subjects then performed graded expirations from total lung capacity to residual volume at different efforts to account for TGC (MEFV(pre-TGC)). Post-exercise FVC (MEFV(post)) and post-exercise graded expirations (MEFV(post-TGC)) were performed to account for bronchodilation and TGC. EFL occurred in 29 subjects when using MEFV(pre). The magnitude of EFL in these subjects was 47+/-23% which was significantly higher than MEFV(pre-TGC) (28+/-28%), MEFV(post) (24+/-27%) and MEFV(post-TGC) (19+/-24%) (P<0.00001). Using the traditional MEFV(pre) curve overestimates and falsely detects EFL since it does not account for TGC and bronchodilation. PMID:20138157

Guenette, Jordan A; Dominelli, Paolo B; Reeve, Sabrina S; Durkin, Christopher M; Eves, Neil D; Sheel, A William

2010-02-04

305

Integration of Resting-State FMRI and Diffusion-Weighted MRI Connectivity Analyses of the Human Brain: Limitations and Improvement.  

PubMed

BACKGROUND: Integration of functional connectivity analysis based on resting-state functional Magnetic Resonance Imaging (fMRI) and structural connectivity analysis based on Diffusion-Weighted Imaging (DWI) has shown great potential to improve understanding of the neural networks in the human brain. However, there are sensitivity and specificity-related interpretation issues that must be addressed. METHODS: We assessed the long-range functional and structural connections of the default-mode, attention, visual and motor networks on 25 healthy subjects. For each network, we first integrated these two analyses based on one common seed region. We then introduced a functional-assisted fiber tracking strategy, where seed regions were defined based on independent component analysis of the resting-state fMRI dataset. RESULTS: The single-seed based technique successfully identified the expected functional connections within these networks at both subject and group levels. However, the success rate of structural connectivity analysis showed a high level of variation among the subjects. The functional-assisted fiber tracking strategy highly improved the rate of successful fiber tracking. CONCLUSIONS: This fMRI/DWI integration study suggests that functional connectivity analysis might be a more sensitive and robust approach in understanding the connectivity between cortical regions, and can be used to improve DWI-based structural connectivity analysis. PMID:23279672

Zhu, David C; Majumdar, Shantanu

2012-12-28

306

Inhibition of Histone Deacetylase Activity in Human Endometrial Stromal Cells Promotes Extracellular Matrix Remodelling and Limits Embryo Invasion  

PubMed Central

Invasion of the trophoblast into the maternal decidua is regulated by both the trophoectoderm and the endometrial stroma, and entails the action of tissue remodeling enzymes. Trophoblast invasion requires the action of metalloproteinases (MMPs) to degrade extracellular matrix (ECM) proteins and in turn, decidual cells express tissue inhibitors of MMPs (TIMPs). The balance between these promoting and restraining factors is a key event for the successful outcome of pregnancy. Gene expression is post-transcriptionally regulated by histone deacetylases (HDACs) that unpacks condensed chromatin activating gene expression. In this study we analyze the effect of histone acetylation on the expression of tissue remodeling enzymes and activity of human endometrial stromal cells (hESCs) related to trophoblast invasion control. Treatment of hESCs with the HDAC inhibitor trichostatin A (TSA) increased the expression of TIMP-1 and TIMP-3 while decreased MMP-2, MMP-9 and uPA and have an inhibitory effect on trophoblast invasion. Moreover, histone acetylation is detected at the promoters of TIMP-1 and TIMP-3 genes in TSA-treated. In addition, in an in vitro decidualized hESCs model, the increase of TIMP-1 and TIMP-3 expression is associated with histone acetylation at the promoters of these genes. Our results demonstrate that histone acetylation disrupt the balance of ECM modulators provoking a restrain of trophoblast invasion. These findings are important as an epigenetic mechanism that can be used to control trophoblast invasion.

Atkinson, Stuart P.; Quinonero, Alicia; Martinez, Sebastian; Pellicer, Antonio; Simon, Carlos

2012-01-01

307

Human adipose-derived mesenchymal stem cells engineered to secrete IL-10 inhibit APC function and limit CNS autoimmunity.  

PubMed

Interleukin (IL)-10 is an important immunoregulatory cytokine shown to impact inflammatory processes as manifested in patients with multiple sclerosis (MS) and in its animal model, experimental autoimmune encephalomyelitis (EAE). Several lines of evidence indicate that the effectiveness of IL-10-based therapies may be dependent on the timing and mode of delivery. In the present study we engineered the expression of IL-10 in human adipose-derived mesenchymal stem cells (Adi-IL-10-MSCs) and transplanted these cells early in the disease course to mice with EAE. Adi-IL-10-MSCs transplanted via the intraperitoneal route prevented or delayed the development of EAE. This protective effect was associated with several anti-inflammatory response mechanisms, including a reduction in peripheral T-cell proliferative responses, a decrease in pro-inflammatory cytokine secretion as well as a preferential inhibition of Th17-mediated neuroinflammation. In vitro analyses revealed that Adi-IL-10-MSCs inhibited the phenotypic maturation, cytokine production and antigen presenting capacity of bone marrow-derived myeloid dendritic cells, suggesting that the mechanism of action may involve an indirect effect on pathogenic T-cells via the modulation of antigen presenting cell function. Collectively, these results suggest that early intervention with gene modified Adi-MSCs may be beneficial for the treatment of autoimmune diseases such as MS. PMID:23369732

Payne, Natalie L; Sun, Guizhi; McDonald, Courtney; Moussa, Leon; Emerson-Webber, Ashley; Loisel-Meyer, Séverine; Medin, Jeffrey A; Siatskas, Christopher; Bernard, Claude C A

2013-01-29

308

Activity limitations in patients with neuromuscular disorders: a responsiveness study of the ACTIVLIM questionnaire.  

PubMed

Recently, a self-reported scale of activity limitations, the ACTIVLIM questionnaire, was developed and validated in patients with neuromuscular disorders (NMD). The purpose of this study was to investigate its sensitivity to change. One hundred thirty-two patients with NMD (mean age, range: 31, 6-80) were assessed twice, with 21+/-4 months in between, using the ACTIVLIM questionnaire. Mean score change, effect size, standardized response, mean paired t-test and an individual-level statistical approach were calculated for groups of patients according to their self-rated functional status evolution and for three main diagnostic groups (Ambulant and wheelchair-bound Duchenne muscular dystrophy patients, myotonic dystrophy patients, and patients with Charcot-Marie-Tooth neuropathy). The responsiveness indices showed that the change in activity measures was higher in patients who reported deteriorated functional status and in patients with Duchenne muscular dystrophy. The ACTIVLIM questionnaire showed a good sensitivity to change and could be useful in research settings to characterize the disease course of NMD. PMID:19167889

Vandervelde, Laure; Van den Bergh, Peter Y K; Goemans, Nathalie; Thonnard, Jean-Louis

2009-01-23

309

Simulation studies of multiple dipole neuromagnetic source localization: Model order and limits of source resolution  

SciTech Connect

Numerical simulation studies were performed using a multiple dipole source model and a spherical approximation of the head to examine how the resolution of simultaneously active neuromagnetic sources depends upon: (1) source modeling assumptions (i.e., number of assumed dipoles); (2) actual source parameters (e.g., location, orientation, and moment); and (3) measurement errors. Forward calculations were conducted for a series of source configurations in which the number of dipoles, specific dipole parameters, and noise levels were systematically varied. Simulated noisy field distributions were fit by multiple dipole models of increasing model order 1, 2, [center dot][center dot][center dot], 6 and alternative statistical approaches (i.e., percent of variance, reduced chi-square, and F-ratio) were compared for their effectiveness in determining adequate model order. Limits of spatial resolution were established for a variety of multi-source configurations and noise conditions. Implications for the analysis of empirical data are discussed. 28 refs., 6 figs., 4 tabs.

Supek, S.; Aine, C.J. (Los Alamos National Lab., NM (United States))

1993-06-01

310

Limitations on Recently Suggested Atom Interferometry Mission Concepts for Gravitational Wave Studies  

NASA Astrophysics Data System (ADS)

In late 2011, suggestions were made of two new atom interferometry mission concepts for gravitational wave studies. [A presentation by B. N. Saif on these concepts is available on the NASA Physics of the Cosmos website under ``Workshop on Gravitational Wave Mission Architectural Concepts'' (Dec. 20-21, 2011)]. The concepts were for measurements between atom clouds separated by distances of L=500 m or L=500 km. At GW frequencies of 0.1 to 10 Hz, sinusoidal variations in the separations dX between two parts of the atom wavefunctions would be induced by motion of the nulls in the optical potential, using the Bloch oscillation approach. But some apparent limitations of this approach are as follows: the S/N required for achieving the strain sensitivities shown appears to be much higher than the value given in the example in the presentation; the large sinusoidal variations required in the control laser frequency make it difficult to use high finesse cavity mode-cleaners to reduce the effects of laser wavefront aberration fluctuations; very small fluctuations in the temperature or size of the atom clouds would cause serious additional noise, particularly for the L=500 m case; and for the L=500 mission concept, the 10-20 W suggested laser power does not seem to permit keeping the spontaneous emission rate low. However, the main issue is that the required atom interferometry systems appear to be far more complex than the gravitational reference sensors that they would replace.

Bender, Peter L.

2012-03-01

311

Limitations of rapid HIV-1 tests during screening for trials in Uganda: diagnostic test accuracy study  

PubMed Central

Objective To evaluate the limitations of rapid tests for HIV-1. Design Diagnostic test accuracy study. Setting Rural Rakai, Uganda. Participants 1517 males aged 15-49 screened for trials of circumcision for HIV prevention. Main outcome measures Sensitivity, specificity, negative predictive values, and positive predictive values of an algorithm using three rapid tests for HIV, compared with the results of enzyme immunoassay and western blotting as the optimal methods. Results Rapid test results were evaluated by enzyme immunoassay and western blotting. Sensitivity was 97.7%. Among 639 samples where the strength of positive bands was coded if the sample showed positivity for HIV, the algorithm had low specificity (94.1%) and a low positive predictive value (74.0%). Exclusion of 37 samples (5.8%) with a weak positive band improved the specificity (99.6%) and positive predictive value (97.7%). Conclusion Weak positive bands on rapid tests for HIV should be confirmed by enzyme immunoassay and western blotting before disclosing the diagnosis. Programmes using rapid tests routinely should use standard serological assays for quality control. Trial registration Clinical Trials NCT00425984.

Makumbi, Fredrick; Serwadda, David; Lutalo, Tom; Nalugoda, Fred; Opendi, Pius; Kigozi, Godfrey; Reynolds, Steven J; Sewankambo, Nelson K; Wawer, Maria J

2007-01-01

312

The Limits of Collaboration: A Qualitative Study of Community Ethical Review of Environmental Health Research  

PubMed Central

Objectives. We assessed the effectiveness of various systems of community participation in ethical review of environmental health research. Methods. We used situation analysis methods and a global workspace theoretical framework to conduct comparative case studies of 3 research organizations at 1 medical center. Results. We found a general institutional commitment to community review as well as personal commitment from some participants in the process. However, difficulty in communicating across divides of knowledge and privilege created serious gaps in implementation, leaving research vulnerable to validity threats (such as misinterpretation of findings) and communities vulnerable to harm. The methods used in each collaboration solved some, but not all, of the problems that hindered communication. Conclusions. Researchers, community spokespersons, and institutional review boards constitute organizational groups with strong internal ties and highly developed cultures. Few cross-linkages and little knowledge of each other cause significant distortion of information and other forms of miscommunication between groups. Our data suggest that organizations designed to protect human volunteers are in the best position to take the lead in implementing community review.

Fullilove, Robert E.; Kaufman, Molly Rose; Wallace, Rodrick; Fullilove, Mindy Thompson

2009-01-01

313

Impact of Design Trade Studies on System Human Resources.  

National Technical Information Service (NTIS)

The study was undertaken to accomplish two objectives. The first objective was to identify and classify the characteristics of conceptual design trade studies that have high potential impact on human resource requirements of Air Force weapon systems. The ...

G. V. Whalen W. B. Askren

1974-01-01

314

Duckweed (Lemna minor) as a Model Plant System for the Study of Human Microbial Pathogenesis  

Microsoft Academic Search

BackgroundPlant infection models provide certain advantages over animal models in the study of pathogenesis. However, current plant models face some limitations, e.g., plant and pathogen cannot co-culture in a contained environment. Development of such a plant model is needed to better illustrate host-pathogen interactions.Methodology\\/Principal FindingsWe describe a novel model plant system for the study of human pathogenic bacterial infection on

Yong Zhang; Yangbo Hu; Baoyu Yang; Fang Ma; Pei Lu; Lamei Li; Chengsong Wan; Simon Rayner; Shiyun Chen; Pere-Joan Cardona

2010-01-01

315

Content, Social, and Metacognitive Statements: An Empirical Study Comparing Human-Human and Human-Computer Tutorial Dialogue.  

National Technical Information Service (NTIS)

We present a study which compares human-human computer-mediated tutoring with two computer tutoring systems based on the same materials but differing in the type of feedback they provide. Our results show that there are significant differences in interact...

G. E. Campbell J. D. Moore K. M. Harrison M. O. Dzikovska N. B. Steinhauser

2010-01-01

316

Human Effectiveness and Risk Characterization of the Electromuscular Incapacitation Device - A Limited Analysis of the TASER. Part 1. Technical Report.  

National Technical Information Service (NTIS)

A Human Effectiveness and Risk Characterization for Electromuscular Incapacitation (EMI) reflects the results from three workshops (data gathering/sharing, peer consultation, and independent external review) evaluating two EMI devices: the M26 and X26 TAS...

A. Maier P. Nance P. Price C. J. Sherry J. P. Reilly

2005-01-01

317

Theoretical Study of Operational Limits of High-Speed Quantum Dot Lasers.  

National Technical Information Service (NTIS)

A comprehensive theory of the modulation response of quantum dot (QD) lasers is developed. The factors limiting the modulation bandwidth are identified and the highest possible bandwidth is calculated. The highest bandwidth increases directly with overlap...

L. V. Asryan

2012-01-01

318

CLIMATE CHANGE: Information on Limitations and Assumptions of DOE's Five-Lab Study.  

National Technical Information Service (NTIS)

Human activities, primarily those related to energy production and use, are increasing the concentrations of carbon dioxide and other 'greenhouse gases' in the atmosphere. These heat-trapping gases are believed to contribute to global warming, which could...

W. F. McGee M. Nadji J. R. Beusse P. L. Bartholomew H. C. Greene

1998-01-01

319

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

320

A strategy to study genotoxicity: application to aquatic toxins, limits and solutions  

Microsoft Academic Search

Humans can be exposed to aquatic toxins mainly through contamination of food and water (drinking and recreational). Among\\u000a these toxins, contamination by both phycotoxins occurring in shellfish and cyanotoxins mostly involved in freshwater bodies\\u000a are of concern for public health. Whereas regulations exist to evaluate the genotoxicity of most compounds to which humans\\u000a are exposed, including drugs and chemicals, no

Valérie Fessard; Ludovic Le Hégarat

2010-01-01

321

Abdominal fat distribution and functional limitations and disability in a biracial cohort: the Atherosclerosis Risk in Communities Study  

Microsoft Academic Search

OBJECTIVE:To examine the associations of abdominal fat and obesity with functional limitations and disability in late adulthood.DESIGN:Longitudinal, cohort study.PARTICIPANTS:African American and white men and women aged 45–64 y at baseline with measured waist circumference, waist-to-hip ratio (WHR), and body mass index (BMI) who participated in the Atherosclerosis Risk in Communities (ARIC) Study (n=9416).OUTCOME MEASURES:Self-reported functional limitations, activities of daily living

D K Houston; J Stevens; J Cai

2005-01-01

322

A pilot study using the internet to study patterns of party drug use: processes, findings and limitations.  

PubMed

Since the 1990s there has been a rise in both the prevalence of party drug use in Australia and the use of party drug-related websites. This study investigates whether it is feasible to recruit and survey party drug users via the internet. It took place in Victoria, Australia. Participants were directed to a website where they completed a brief, structured internet-based survey. A total of 460 responses were received over 31 days, 393 of which fitted all inclusion criteria. The sample consisted predominately of young, male polydrug users and is one of the largest samples of party drug users in Australia reported thus far. It was concluded that it is feasible to recruit and survey current party drug users via the internet and that this method is quicker and cheaper than traditional survey methods, although samples are not necessarily representative of the party drug-using population. Other limitations and advantages are discussed. PMID:17364852

Miller, Peter G; Johnston, Jennifer; McElwee, Paul R; Noble, Rick

2007-03-01

323

Identifying the genomic determinants of aging and longevity in human population studies: Progress and challenges  

PubMed Central

Human lifespan variation is mainly determined by environmental factors, whereas the genetic contribution is 25–30% and expected to be polygenic. Two complementary fields go hand in hand in order to unravel the mechanisms of biological aging: genomic and biomarker research. Explorative and candidate gene studies of the human genome by genetic, transcriptomic, and epigenomic approaches have resulted in the identification of a limited number of interesting positive linkage regions, genes, and pathways that contribute to lifespan variation. The possibilities to further exploit these findings are rapidly increasing through the use of novel technologies, such as next-generation sequencing. Genomic research is progressively being integrated with biomarker studies on aging, including the application of (noninvasive) deep phenotyping and omics data – generated using novel technologies – in a wealth of studies in human populations. Hence, these studies may assist in obtaining a more holistic perspective on the role of the genome in aging and lifespan regulation.

Deelen, Joris; Beekman, Marian; Capri, Miriam; Franceschi, Claudio; Slagboom, P Eline

2013-01-01

324

Has untargeted sexual health promotion for young people reached its limit? A quasi-experimental study  

PubMed Central

Background Theoretically, there may be benefit in augmenting school-based sexual health education with sexual health services, but the outcomes are poorly understood. Healthy Respect 2 (HR2) combined sex education with youth-friendly sexual health services, media campaigns and branding, and encouraged joint working between health services, local government and the voluntary sector. This study examined whether HR2: (1) improved young people's sexual health knowledge, attitudes, behaviour and use of sexual health services and (2) reduced socioeconomic inequalities in sexual health. Methods A quasi-experiment in which the intervention and comparison areas were matched for teenage pregnancy and terminations, and schools were matched by social deprivation. 5283 pupils aged 15–16?years (2269 intervention, 3014 comparison) were recruited to cross-sectional surveys in 2007, 2008 and 2009. Results The intervention improved males’ and, to a lesser extent, females’ sexual health knowledge. Males’ intention to use condoms, and reported use of condoms, was unaffected, compared with a reduction in both among males in the comparison arm. Although females exposed to the intervention became less accepting of condoms, there was no change in their intention to use condoms and reported condom use. Pupils became more tolerant of sexual coercion in both the intervention and comparison arms. Attitudes towards same-sex relationships remained largely unaffected. More pupils in the HR2 area used sexual health services, including those from lower socioeconomic backgrounds. This aside, sexual health inequalities remained. Conclusions Combining school-based sex education and sexual health clinics has a limited impact. Interventions that address the upstream causes of poor sexual health, such as a detrimental sociocultural environment, represent promising alternatives. These should prioritise the most vulnerable young people.

Elliott, Lawrie; Henderson, Marion; Nixon, Catherine; Wight, Daniel

2013-01-01

325

Cytokine treatment or accessory cells are required to initiate engraftment of purified primitive human hematopoietic cells transplanted at limiting doses into NOD\\/SCID mice  

Microsoft Academic Search

Little is known about the cell types or mechanisms that underlie the engraftment process. Here, we have examined parameters affecting the engraftment of purified human Lin?CD34+CD38? normal and AML cells transplanted at limiting doses into NOD\\/SCID recipients. Mice transplanted with 500 to 1000 Lin?CD34+CD38? cord blood (CB) or AML cells required the co-transplantation of accessory cells (ACs) or short-term in

D Bonnet; M Bhatia; JCY Wang; U Kapp; JE Dick

1999-01-01

326

The utilization of humanized mouse models for the study of human retroviral infections  

PubMed Central

The development of novel techniques and systems to study human infectious diseases in both an in vitro and in vivo settings is always in high demand. Ideally, small animal models are the most efficient method of studying human afflictions. This is especially evident in the study of the human retroviruses, HIV-1 and HTLV-1, in that current simian animal models, though robust, are often expensive and difficult to maintain. Over the past two decades, the construction of humanized animal models through the transplantation and engraftment of human tissues or progenitor cells into immunocompromised mouse strains has allowed for the development of a reconstituted human tissue scaffold in a small animal system. The utilization of small animal models for retroviral studies required expansion of the early CB-17 scid/scid mouse resulting in animals demonstrating improved engraftment efficiency and infectivity. The implantation of uneducated human immune cells and associated tissue provided the basis for the SCID-hu Thy/Liv and hu-PBL-SCID models. Engraftment efficiency of these tissues was further improved through the integration of the non-obese diabetic (NOD) mutation leading to the creation of NODSCID, NOD/Shi-scid IL2r?-/-, and NOD/SCID ?2-microglobulinnull animals. Further efforts at minimizing the response of the innate murine immune system produced the Rag2-/-?c-/- model which marked an important advancement in the use of human CD34+ hematopoietic stem cells. Together, these animal models have revolutionized the investigation of retroviral infections in vivo.

Van Duyne, Rachel; Pedati, Caitlin; Guendel, Irene; Carpio, Lawrence; Kehn-Hall, Kylene; Saifuddin, Mohammed; Kashanchi, Fatah

2009-01-01

327

Human Needs and Human Interdependence. Social Studies Interim Grade Guide for Grade One.  

ERIC Educational Resources Information Center

|The social studies curriculum for grade 1 in Manitoba, Canada is presented. The focus of this guide is human needs and human interdependence. Some objectives are to explore: (1) distinctions between needs and wants; (2) various groupings and relationships, such as families, friendships, and communities; (3) ways people are dependent upon their…

Manitoba Dept. of Education, Winnipeg. Curriculum Development Branch.

328

Humans as a Case Study for the Evidence of Evolution.  

ERIC Educational Resources Information Center

Discusses the strengths of the many lines of scientific evidence supporting the idea of human evolution and the importance of the agreement that exists between them. Argues that using humans as a case study in evolution allows educators to illustrate broader aspects of the nature of science and how the overall strength of any scientific…

Nickels, Martin

1998-01-01

329

Quinacrine studies of sex chromatin and nucleoli in human Brain  

Microsoft Academic Search

Quinacrine fluorescent studies of sex chromatin in human neurons indicate that the distal portion of the Y chromosome is constantly seen in association with the nucleolus in the male. The degree of association between the “Y body” and the nucleolus in other cell types is much lower. The degree of association between the X chromatin and the nucleolus in human

Robert J. Iorio; Herman E. Wyandt

1973-01-01

330

Study on Human-Computer Interaction platform for computer wargame  

Microsoft Academic Search

Based on human-computer interaction (HCI) and visualization technologies, we focused on the research of the human-computer interaction platform of the wargame. Starting with analyzing the handcraft wargame, we studied the key technologies in the representation modules for battlefield environment and situation of battlefield, and finally set up a HCI platform model of the wargame. Testing experiment indicated that our work

Liu Jihong; Xu Xiaodong; Xu Xinhe

2008-01-01

331

The Study of Human Behavior Dynamics Based on Blogosphere  

Microsoft Academic Search

Blog and microblog have become one of the most popular applications which individuals could be the message source. Therefore, interactivities between individuals have been largely enhanced in today's world. In terms of message delivery and human behavior, understanding the mechanism behind is of significance. Though human dynamics has become a popular subject, most of relevant studies so far used the

Yading Song; Chuang Zhang; Ming Wu

2010-01-01

332

Enhanced transmural fiber rotation and connexin 43 heterogeneity are associated with an increased upper limit of vulnerability in a transgenic rabbit model of human hypertrophic cardiomyopathy.  

PubMed

Human hypertrophic cardiomyopathy, characterized by cardiac hypertrophy and myocyte disarray, is the most common cause of sudden cardiac death in the young. Hypertrophic cardiomyopathy is often caused by mutations in sarcomeric genes. We sought to determine arrhythmia propensity and underlying mechanisms contributing to arrhythmia in a transgenic (TG) rabbit model (beta-myosin heavy chain-Q403) of human hypertrophic cardiomyopathy. Langendorff-perfused hearts from TG (n=6) and wild-type (WT) rabbits (n=6) were optically mapped. The upper and lower limits of vulnerability, action potential duration (APD) restitution, and conduction velocity were measured. The transmural fiber angle shift was determined using diffusion tensor MRI. The transmural distribution of connexin 43 was quantified with immunohistochemistry. The upper limit of vulnerability was significantly increased in TG versus WT hearts (13.3+/-2.1 versus 7.4+/-2.3 V/cm; P=3.2e(-5)), whereas the lower limits of vulnerability were similar. APD restitution, conduction velocities, and anisotropy were also similar. Left ventricular transmural fiber rotation was significantly higher in TG versus WT hearts (95.6+/-10.9 degrees versus 79.2+/-7.8 degrees; P=0.039). The connexin 43 density was significantly increased in the mid-myocardium of TG hearts compared with WT (5.46+/-2.44% versus 2.68+/-0.77%; P=0.024), and similar densities were observed in the endo- and epicardium. Because a nearly 2-fold increase in upper limit of vulnerability was observed in the TG hearts without significant changes in APD restitution, conduction velocity, or the anisotropy ratio, we conclude that structural remodeling may underlie the elevated upper limit of vulnerability in human hypertrophic cardiomyopathy. PMID:17885214

Ripplinger, Crystal M; Li, Wenwen; Hadley, Jennifer; Chen, Junjie; Rothenberg, Florence; Lombardi, Raffaella; Wickline, Samuel A; Marian, Ali J; Efimov, Igor R

2007-09-20

333

Helium-oxygen ventilation in the presence of expiratory flow-limitation: a model study.  

PubMed

A comparison between air and heliox (80% helium-20% oxygen) ventilation was performed using a mathematical, non-linear dynamic, morphometric model of the respiratory system. Different obstructive conditions, all causing expiratory flow limitation (EFL), were simulated during mechanical ventilation to evaluate and interpret the effects of heliox on tidal EFL and dynamic hyperinflation. Relative to air ventilation, intrinsic positive end-expiratory pressure did not change with heliox if the obstruction was limited to the peripheral airways, i.e. beyond the seventh generation. When central airways were also involved, heliox reduced dynamic hyperinflation (DH) if the flow-limiting segment remained in the fourth to seventh airway generation during the whole expiration, but produced only minor effects if, depending on the contribution of peripheral to total apparent airway resistance, the flow-limiting segment moved eventually to the peripheral airways. In no case did heliox abolish EFL occurring with air ventilation, indicating that any increase in driving pressure would be without effect on DH. Hence, to the extent that chronic obstructive pulmonary disease (COPD) affects primarily the peripheral airways, and causes EFL through the same mechanisms operating in the model, heliox administration should not be expected to appreciably reduce DH in the majority of COPD patients who are flow-limited at rest. PMID:17293172

Brighenti, Chiara; Barbini, Paolo; Gnudi, Gianni; Cevenini, Gabriele; Pecchiari, Matteo; D'Angelo, Edgardo

2007-01-12

334

Fatal human monocytic ehrlichiosis: a case study.  

PubMed

Human ehrlichiosis is the term for a collection of tick-borne diseases caused primarily by obligate intracellular bacteria of the Ehrlichia species. Ehrlichiosis is characterized by a mild to severe illness, with approximately 3-5% of cases proving fatal despite receiving appropriate care. This report presents the case of a 60 year-old woman who was found collapsed and unresponsive in her home after an indeterminate time; possibly for up to 48 h. Despite rigorous resuscitative care and antibiotic treatment, the patient lapsed into multi-organ failure and died. Subsequent analysis by microscopic examination, PCR and immunohistochemistry revealed the patient died from an infection of Ehrlichia chaffeensis. Clinicians and pathologists must be aware of this emergent disease in order to make a timely and appropriate diagnosis. Discussion of the patient's clinical, laboratory and autopsy findings as well as treatment of Ehrlichia chaffeensis infections is presented. PMID:21279705

Pavelites, Joseph J; Prahlow, Joseph A

2011-01-30

335

Study on Required Performance of Fault Current Limiter for Dispersed Generator  

NASA Astrophysics Data System (ADS)

It is expected that a number of dispersed generators interconnecting with power distribution systems will be increased with progress of deregulation in electric power industry. In order to allow large capacity of the interconnection, a certain current limitation measure is required in present distribution systems because of allowable short circuit capacity as a restriction. One of effective measures is fault current limiter (FCL) which suppress short circuit current within a time of half cycle. However, a required performance of FCL applied to dispersed generators is not made clear. The authors look for necessary conditions on the FCL performance for above-mentioned purpose using EMTP simulation. This paper presents necessary performance of FCL, which includes a commutation type FCL with resistance and reactance as a limitation element.

Genji, Takamu; Miyazato, Kenji; Tsutsushio, Hidefumi; Nishiwaki, Tadao

336

A study of the human decomposition sequence in central Texas.  

PubMed

Decomposition studies utilizing nonhuman subjects as human analogues are well established, but fewer studies utilizing intact human remains exist. This study provides data from a controlled decomposition study involving human remains in Central Texas. A 63.5-kg unmodified cadaver was placed in an open-air site and observed over a 10-week period from April 11 through June 19, 2008. A wire enclosure restricted scavenger access. State of decomposition and environmental conditions were recorded daily for the first 36 days and then every 2 weeks thereafter. Results indicated a high degree of correlation with other decomposition studies originating in the southwestern United States, although slight deviations for the average duration of early events were noted. The data were also utilized to test a quantitative method for estimating the postmortem interval. Results indicated preliminary support for a quantitative approach. Additional research is encouraged to further establish the human decomposition data set for Central Texas. PMID:20840291

Parks, Connie L

2010-09-14

337

The limits of technological optimism  

Microsoft Academic Search

Summary ‘Technological optimism’ is the doctrine that a growing number of technological improvements in such areas as food production, environmental quality and energy will sustain life as human population soars. It evolved as a response to the Malthusian study The Limits to Growth (The Club of Rome, 1972). Like population biologist Paul Ehrlich, Professor James Krier of the University of

Andrew D. Basiago

1994-01-01

338

Belief, Awareness, and Limited Reasoning  

Microsoft Academic Search

Several new logics for belief and knowledge are introduced and studied, all of which have the property that agents are not logically omniscient. In particular, in these logics, the set of beliefs of an agent does not necessarily contain all valid formulas. Thus, these logics are more suitable than traditional logics for modelling beliefs of humans (or machines) with limited

Ronald Fagin; Joseph Y. Halpern

1987-01-01

339

[Reactogenicity and immunological effectiveness of an oral cholera chemical vaccine in a limited controlled experiment with human revaccination].  

PubMed

Oral cholera chemical vaccine in the doses tested (2 and 3 tablets) proved to be areactogenic, harmless and immunologically effective in a controlled limited trial in 150 volunteers. By the results of titration of specific antitoxins and vibriocidal antibodies in the blood serum, as well as of coproantibodies a dose of 2 tablets was chosen as the optimal one. PMID:371293

Sumarokov, A A; Ivanov, N R; Lelikov, V L; Dzhaparidze, M N; Karaeva, L T

1978-01-01

340

Managerial Leverage Is Limited by the Extent of the Market: Hierarchies, Specialization, and the Utilization of Lawyers' Human Capital  

Microsoft Academic Search

This paper examines the role of hierarchies in the organization of human-capital-intensive production. We develop an equilibrium model of hierarchical organization and provide empirical evidence based on confidential data on thousands of law offices. The equilibrium assignment of individuals to hierarchical positions varies with the degree of field specialization, which increases as the extent of the market increases. As individuals'

Luis Garicano

2007-01-01

341

Convergent integration of animal model and human studies of bipolar disorder (manic-depressive illness).  

PubMed

Animal models and human studies of bipolar disorder and other psychiatric disorders are becoming increasingly integrated, prompted by recent successes. Particularly for genomics, the convergence and integration of data across species, experimental modalities and technical platforms is providing a fit-to-disease way of extracting reproducible and biologically important signal, in sharp contrast to the fit-to-cohort effect, disappointing findings to date, and limited reproducibility of human genetic analyses alone. Such work in psychiatry can provide an example of how to address other genetically complex disorders, and in turn will benefit by incorporating concepts from other areas, such as cancer biology and diabetes. PMID:20817606

Le-Niculescu, Helen; Patel, Sagar D; Niculescu, Alexander B

2010-10-01

342

Creating a Game Development Course with Limited Resources: An Evaluation Study  

ERIC Educational Resources Information Center

This article provides an overview of the challenges in implementing a game development course with limited resources in computing curricula. An approach to a holistic game development course is outlined in terms of its organization, software, and instructional methods. The course had 23 students enrolled in its first offering and was…

Ritzhaupt, Albert D.

2009-01-01

343

Nitrogen Limitation of Terrestrial Net Primary Production: Global Patterns From Field Studies with Nitrogen Fertilization  

Microsoft Academic Search

Net primary production (NPP) transfers carbon from the atmospheric CO2 pool into the biosphere. Experimental evidence demonstrates that NPP is often limited by nitrogen availability. Hence, accelerated nitrogen availability due to fertilizer production, fossil fuel use, and biomass burning could stimulate global NPP. Over the next century, these nitrogen sources are expected to both increase in strength and expand from

D. S. Lebauer; K. K. Treseder

2006-01-01

344

Limited ischemic necrosis despite prolonged basilar artery occlusion treated with local thrombolysis: A clinicopathologic study  

Microsoft Academic Search

Based on published case series, intra-arterial thrombolysis for basilar artery occlusion reduces mortality and improves outcome even when performed after considerable delays. In contrast, the current use of intravenous thrombolysis is limited to a 3-hour time window. The longer time window for intervention in patients with basilar artery occlusion may vary based on individual clinical features, such as collateral circulation

Paul T. Akins; Surl L. Nielsen; David J. Seidenwurm

2001-01-01

345

High-Stakes Testing, High School Graduation, and Limited English Proficient Students: A Case Study  

ERIC Educational Resources Information Center

|The educational accountability systems of both the No Child Left Behind (NCLB) Act of 2001 and the state of Florida (as of 1999) were modeled after Texas' system, despite its flaws. NCLB reaches for all students to achieve academic proficiency and designates students with limited English proficiency (LEP) as an important subgroup. As we work with…

Giambo, Debra A.

2010-01-01

346

Limiting factor analysis and regulation for urban ecosystems—A case study of Ningbo, China  

NASA Astrophysics Data System (ADS)

Considering the importance of supporting system for the urban ecosystem development, the urban ecological carrying capacity (UECC) representing the supporting functions of biophysical environment for urban development is introduced into the analysis of urban ecosystem degradation. It is proposed in this paper that the urban ecosystem degradation can be attributed to the imbalance between supply and demand of UECC, i.e. the conflict between the infinite demand of urban development and finite supply of biophysical supporting system, which can be mainly described by the dominant limiting factors of UECC. Through the shortage indices of various factors that denoted by the ratio of the gap between the demand and supply to the demand, the limiting factors of UECC can be identified and graded with different levels. The urban ecosystem degradation can thus be regulated by adjusting the relationship of supply and demand in terms of limiting factors from both the layers of technical practice and goal-based government management. As for Ningbo City, the shortage of water resources quantity, the pressure of SO 2 emission, insufficiency of sewage treatment and green area are the prominent limiting factors and corresponding regulation scheme is thereafter suggested to adjust the relationship between supply and demand of UECC.

Yang, Z. F.; Su, M. R.; Zhang, B.; Zhang, Y.; Hu, T. L.

2010-09-01

347

In the Death Zone: A study of limits in the 1996 Mount Everest disaster  

Microsoft Academic Search

This article examines the May 1996 Everest disaster through the lens of limits and liminality to provide an alternative interpretation of the significance of the event as a counterpoint to existing accounts. The Everest disaster is an example of management under the most extreme conditions and also an example of a common managerial mindset that is prevalent in the literature

Sue Tempest; Ken Starkey; Christine Ennew

2007-01-01

348

Environmental characteristics in oligotrophic waters: Data evaluation and statistical limitations in water quality studies  

Microsoft Academic Search

Standard statistical tests of nutrient variability in the euphotic layer of an oligotrophic system in the S.E. Aegean Sea were performed. Practical problems resulting from data handling, such as high errors associated with low concentrations, nonlinearity and interaction among variables were examined. The practical problems in the analysis of environmental data, arising from statistical limitations were considered: linear correlations between

Penelope Vounatsou; Michael Karydis

1991-01-01

349

Design and study of a saturated dc reactor fault current limiter  

Microsoft Academic Search

Since magnetic core of an inductor is easily saturated and then absorbs extra energy due to saturation, most of inductors are designed with an air core. The inductor requires so many wires to make large inductance and these expensive coils are one of the weak points of the dc reactor type fault current limiter (FCL). To solve this problem, reverse

M. B. B. Sharifian; M. Abapour; E. Babaei

2009-01-01

350

A study of the numerical limitations of a homogenous rectangular prism formula  

NASA Astrophysics Data System (ADS)

In computing accurately the total gravitational attraction of arbitrarily complicated source body, the widely used standard method is to approximate it by a sum of attractions from (possibly many) disjoint rectangular prisms of constant density. Such methods are notorious for being computationally slow but regarded as being arbitrarily accurate; the finer the prisms that describe the source body the better the approximation of the total gravitational attraction. Mathematically, the attraction of the individual prisms is computed using the so-called rectangular homogenous prism formula which is a definite volume integral (i.e. a triple integration). The standard application (in Cartesian coordinates) involves an alignment of the Cartesian frames of reference of the field point and the source point support, so that the x-, y- and z-axis of the aligned Cartesian reference frames are also aligned with the sides of the prism. In computing the prism attraction the values of a primitive function are determined for the coordinates of the prism corners. In short, the definite integral involves the alternating subtraction and addition of the values of a primitive function. On a computer, the values of a primitive function are truncated by a finite representation (32BIT, 64BIT). This truncated representation of a function results in numerical instabilities of the rectangular prism formula; i.e. the value of a primitive function for each corner point of the prism is accurate, but not the final definite integral. In this study we will quantify this numerical instability of the homogenous prism formula for the gravitational potential, for the components of the gravitational vector, and for all the components of the 2nd order tensor of the gravitational gradients. Furthermore, we will investigate how the quadruple precision (128 BIT representation of reals on a computer) improves the stability of the prism formula. In practical terms, the numerical instability of the prism formula puts limitations on how well the sum of the gravitational attractions of a large number of fine homogenous rectangular prisms describing a complicated source will approximate the total gravitational attraction of a complicated source body.

Strykowski, Gabriel

2013-04-01

351

Experimental design for estimating parameters of rate-limited mass transfer: Analysis of stream tracer studies  

USGS Publications Warehouse

Tracer experiments are valuable tools for analyzing the transport characteristics of streams and their interactions with shallow groundwater. The focus of this work is the design of tracer studies in high-gradient stream systems subject to advection, dispersion, groundwater inflow, and exchange between the active channel and zones in surface or subsurface water where flow is stagnant or slow moving. We present a methodology for (1) evaluating and comparing alternative stream tracer experiment designs and (2) identifying those combinations of stream transport properties that pose limitations to parameter estimation and therefore a challenge to tracer test design. The methodology uses the concept of global parameter uncertainty analysis, which couples solute transport simulation with parameter uncertainty analysis in a Monte Carlo framework. Two general conclusions resulted from this work. First, the solute injection and sampling strategy has an important effect on the reliability of transport parameter estimates. We found that constant injection with sampling through concentration rise, plateau, and fall provided considerably more reliable parameter estimates than a pulse injection across the spectrum of transport scenarios likely encountered in high-gradient streams. Second, for a given tracer test design, the uncertainties in mass transfer and storage-zone parameter estimates are strongly dependent on the experimental Damkohler number, DaI, which is a dimensionless combination of the rates of exchange between the stream and storage zones, the stream-water velocity, and the stream reach length of the experiment. Parameter uncertainties are lowest at DaI values on the order of 1.0. When DaI values are much less than 1.0 (owing to high velocity, long exchange timescale, and/or short reach length), parameter uncertainties are high because only a small amount of tracer interacts with storage zones in the reach. For the opposite conditions (DaI >> 1.0), solute exchange rates are fast relative to stream-water velocity and all solute is exchanged with the storage zone over the experimental reach. As DaI increases, tracer dispersion caused by hyporheic exchange eventually reaches an equilibrium condition and storage-zone exchange parameters become essentially nonidentifiable.

Wagner, B. J.; Harvey, J. W.

1997-01-01

352

Two alternative models of health behaviour and recovery from activity limitations due to acute injury: A prospective study  

Microsoft Academic Search

Cognitions influence recovery from activity limitations. In this study we aimed to independently test, compare and combine the common sense self-regulation model (CS-SRM) and social cognitive theory (SCT) in predicting recovery from activity limitations due to acute injury. Measures were gathered at two time points 5–6 weeks apart. The sample consisted of 146 university students (Mean age: 21.86, SD: 4.83,

Gerard J. Molloy; Falko Sniehotta; Marie Johnston

2009-01-01

353

Meta-Profiles of Gene Expression during Aging: Limited Similarities between Mouse and Human and an Unexpectedly Decreased Inflammatory Signature  

PubMed Central

Background Skin aging is associated with intrinsic processes that compromise the structure of the extracellular matrix while promoting loss of functional and regenerative capacity. These processes are accompanied by a large-scale shift in gene expression, but underlying mechanisms are not understood and conservation of these mechanisms between humans and mice is uncertain. Results We used genome-wide expression profiling to investigate the aging skin transcriptome. In humans, age-related shifts in gene expression were sex-specific. In females, aging increased expression of transcripts associated with T-cells, B-cells and dendritic cells, and decreased expression of genes in regions with elevated Zeb1, AP-2 and YY1 motif density. In males, however, these effects were contrasting or absent. When age-associated gene expression patterns in human skin were compared to those in tail skin from CB6F1 mice, overall human-mouse correspondence was weak. Moreover, inflammatory gene expression patterns were not induced with aging of mouse tail skin, and well-known aging biomarkers were in fact decreased (e.g., Clec7a, Lyz1 and Lyz2). These unexpected patterns and weak human-mouse correspondence may be due to decreased abundance of antigen presenting cells in mouse tail skin with age. Conclusions Aging is generally associated with a pro-inflammatory state, but we have identified an exception to this pattern with aging of CB6F1 mouse tail skin. Aging therefore does not uniformly heighten inflammatory status across all mouse tissues. Furthermore, we identified both intercellular and intracellular mechanisms of transcriptome aging, including those that are sex- and species-specific.

Swindell, William R.; Johnston, Andrew; Sun, Liou; Xing, Xianying; Fisher, Gary J.; Bulyk, Martha L.; Elder, James T.; Gudjonsson, Johann E.

2012-01-01

354

Use of human epidermal cells in the study of carcinogenesis  

SciTech Connect

Because of the importance of human cells, particularly human epithelial cells, in cancer research, we have studied certain phases or events of carcinogenesis using human epidermal cells in primary culture. (1) We found that human epidermal cells are capable of metabolizing benzo(a)pyrene. Large inter-individual variations are found in the basal and induced arylhydrocarbon-hydroxylase activities. (2) UV-induced unscheduled DNA synthesis was demonstrated in human epidermal cells on autoradiographs. We also found that DNA repair is defective in epidermal cells isolated from xeroderma pigmentosum by a new explant-outgrowth culture. (3) Human epidermal cells are unique in that there is a large number of binding sites to phorbol esters compared with mouse epidermal cells, but there is no down-regulation. Further, human epidermal cells show essentially negative responses to tumor promoters, i.e., no stimulation of DNA synthesis, sugar uptake, and no induction of ornithine decarboxylase activity. (4) Human epidermal cells contain 1.5 x 10(5) binding sites per cell for epidermal growth factor (EGF), whereas squamous cell carcinomas of skin and oral cavity have larger amounts of EGF receptors in the order of 10(6) per cell. (5) Based on the above results, we attempted to transform human epidermal cells by the treatment with chemical carcinogens, but until now no transformation was obtained. 16 references.

Kuroki, T.; Chida, K.; Hosomi, J.; Kondo, S. (Institute of Medical Science, Tokyo (Japan))

1989-05-01

355

Methodology of the study of carcinogens in human populations  

Microsoft Academic Search

Epidemiology, including occupational tumors and other groups at risk; experimental studies; and physicochemical methods of evaluation of environmental carcinogens form the basis of cancer prevention. Hygienic measures of limitation (maximum allowable concentrations) are also discussed.

L. M. Shabad

1978-01-01

356

Voluntary Limit Setting and Player Choice in Most Intense Online Gamblers: An Empirical Study of Gambling Behaviour.  

PubMed

Social responsibility in gambling has become a major issue for the gaming industry. The possibility for online gamblers to set voluntary time and money limits are a social responsibility practice that is now widespread among online gaming operators. The main issue concerns whether the voluntary setting of such limits has any positive impact on subsequent gambling behaviour and whether such measures are of help to problem gamblers. In this paper, this issue is examined through data collected from a representative random sample of 100,000 players who gambled on the win2day gambling website. When opening an account at the win2day site, there is a mandatory requirement for all players to set time and cash-in limits (that cannot exceed 800 per week). During a 3-month period, all voluntary time and/or money limit setting behaviour by a subsample of online gamblers (n = 5,000) within this mandatory framework was tracked and recorded for subsequent data analysis. From the 5,000 gamblers, the 10 % most intense players (as measured by theoretical loss) were further investigated. Voluntary spending limits had the highest significant effect on subsequent monetary spending among casino and lottery gamblers. Monetary spending among poker players significantly decreased after setting a voluntary time limit. The highest significant decrease in playing duration was among poker players after setting a voluntary playing duration limit. The results of the study demonstrated that voluntary limit setting had a specific and significant effect on the studied gamblers. Therefore, voluntary limits appear to show an appropriate effect in the desired target group (i.e., the most gaming intense players). PMID:22948847

Auer, Michael; Griffiths, Mark D

2012-09-01

357

Functional Analysis of the Human Genome:. Study of Genetic Disease  

NASA Astrophysics Data System (ADS)

I will divide my remarks into 3 parts. First, I will give a brief summary of the Human Genome Project. Second, I will describe our work on human chromosome 7 to illustrate how we could contribute to the Project and disease research. Third, I would like to bring across the argument that study of genetic disease is an integral component of the Human Genome Project. In particular, I will use cystic fibrosis as an example to elaborate why I consider disease study is a part of functional genomics.

Tsui, Lap-Chee

2003-04-01

358

Measuring human-error probabilities in drug preparation: a pilot simulation study  

Microsoft Academic Search

Objectives  Designing a safe medication process requires the ability to model its reliability using methods such as probabilistic risk\\u000a assessment (PRA). However, lack of data, especially on human-error probabilities (HEPs), limits its use. To assess whether\\u000a small-scale simulations could help generate HEP data, a pilot study was conducted among nurses and anaesthetists. It focused\\u000a on two core activities, namely, the manual

P. Garnerin; B. Pellet-Meier; P. Chopard; T. Perneger; P. Bonnabry

2007-01-01

359

fMR-adaptation: a tool for studying the functional properties of human cortical neurons  

Microsoft Academic Search

The invariant properties of human cortical neurons cannot be studied directly by fMRI due to its limited spatial resolution. One voxel obtained from a fMRI scan contains several hundred thousands neurons. Therefore, the fMRI signal may average out a heterogeneous group of highly selective neurons. Here, we present a novel experimental paradigm for fMRI, functional magnetic resonance-adaptation (fMR-A), that enables

Kalanit Grill-Spector; Rafael Malach

2001-01-01

360

Identifying selective inhibitors against human cytosolic sialidase NEU2 by substrate specificity studies?  

PubMed Central

Aberrant expression of human sialidases has been shown to associate with various pathological conditions. Despite the effort in sialidase inhibitor design, less attention has been paid to designing specific inhibitors against human sialidases and characterizing the substrate specificity of different sialidases regarding diverse terminal sialic acid forms and sialyl linkages. This is mainly due to the lack of sialoside probes and efficient screening methods, as well as limited access to human sialidases. Low cellular expression level of human sialidase NEU2 hampers its functional and inhibitory studies. Here we report the successful cloning and expression of human sialidase NEU2 in E. coli. About 11 mg of soluble active NEU2 was routinely obtained from 1 L of E. coli cell culture. Substrate specificity studies of the recombinant human NEU2 using twenty para-nitrophenol (pNP)-tagged ?2–3- or ?2–6-linked sialyl galactosides containing different terminal sialic acid forms including common N-acetylneuraminic acid (Neu5Ac), non-human N-glycolylneuraminic acid (Neu5Gc), 2-keto-3-deoxy-D-glycero-D-galacto-nonulosonic acid (Kdn), or their C5-derivatives in a microtiter plate-based high-throughput colorimetric assay identified a unique structural feature specifically recognized by the human NEU2 but not two bacterial sialidases. The results obtained from substrate specificity studies were used to guide the design of a sialidase inhibitor that was selective against human NEU2. The selectivity of the inhibitor was revealed by the comparison of sialidase crystal structures and inhibitor docking studies.

Li, Yanhong; Cao, Hongzhi; Yu, Hai; Chen, Yi; Lau, Kam; Qu, Jingyao; Thon, Vireak; Sugiarto, Go; Chen, Xi

2011-01-01

361

Enhancement of tissue plasminogen activator production from human normal fibroblast IMR90 cells by limitation of cell growth  

Microsoft Academic Search

Tissue plasminogen activator (t-PA) production induced by proteose peptone from IMR-90 cells was investigated. Cells monolayered on plastic surfaces had a higher ability to produce t-PA per unit cell compared to those grown tri-dimensionally on ceramic pieces. Furthermore, confluent monolayers of the cells, which suffered contact inhibition and resulted in limited growth, were available for t-PA production. Repeated batch production

Shinjiro Mitsuda; Naoki Kobayashi; Yoshiaki Matsuda; Yasuharu Itagaki; Akira Suzuki; Eitaro Kumazawa; Kanji Higashio; Gosei Kawanishi

1991-01-01

362

Ischemic preconditioning induces autophagy and limits necrosis in human recipients of fatty liver grafts, decreasing the incidence of rejection episodes  

Microsoft Academic Search

Whether ischemic preconditioning (IP) reduces ischemia\\/reperfusion (I\\/R) injury in human normal and fatty livers remains controversial. We compared two independent groups of liver donor transplants with versus without steatosis to evaluate IP consequences. Liver donors with (n=22) or without (n=28) steatosis either did or did not undergo IP before graft retrieval. Clinical data from the recipients, as well as histological

D Degli Esposti; M Sebagh; P Pham; M Reffas; C Poüs; C Brenner; D Azoulay; A Lemoine

2011-01-01

363

Correction of the aberrations in the human eye with a liquid-crystal spatial light modulator: limits to performance  

Microsoft Academic Search

We evaluated the performance of a liquid-crystal spatial light modulator for static correction of the aberrations in the human eye. By applying phase-retrieval techniques to pairs of double-pass images we first estimated the wave aberration of the eye to be corrected. Then we introduced the opposite phase map in the modulator, which was placed in a plane conjugated with the

Fernando Vargas-Martín; Pedro M. Prieto; Pablo Artal

1998-01-01

364

Limits on charge nonconservation studied by nuclear excitation of sup 127 I  

SciTech Connect

Lower limits on the mean lives of the charge-nonconserving (CNC) processes, {sup 127}I+{ital e}{sub {ital K}}{r arrow}{sup 127}I{sup *}+{nu}, leading to the first (second) excited state of {sup 127}I, were obtained as {tau}{gt}0.58(0.56){times}10{sup 23} yr by searching for the {gamma} decay from the first (second) excited state of {sup 127}I. Upper limits on the ratios of the CNC strengths to the charge-conserving ones through the weak boson and photon mediating processes are obtained as {epsilon}{sub {ital W}}{sup 2}{lt}11{times}10{sup {minus}25} and {epsilon}{sub {gamma}}{sup 2}{lt}4.8{times}10{sup {minus}40}.

Ejiri, H.; Kawasaki, M.; Kinoshita, H.; Ohsumi, H.; Okada, K.; Sano, H. (Department of Physics, Osaka University, Toyonaka, Osaka 560, Japan (JP)); Takasugi, E. (Department of Physics, College of General Education, Osaka University, Toyonaka, Osaka 560, (Japan))

1991-07-01

365

Sharing neuroimaging studies of human cognition  

Microsoft Academic Search

After more than a decade of collecting large neuroimaging datasets, neuroscientists are now working to archive these studies in publicly accessible databases. In particular, the fMRI Data Center (fMRIDC), a high-performance computing center managed by computer and brain scientists, seeks to catalogue and openly disseminate the data from published fMRI studies to the community. This repository enables experimental validation and

Scott T Grafton; Daniel Rockmore; Michael S Gazzaniga

2004-01-01

366

A comparative study of the forming-limit diagram models for sheet steels  

Microsoft Academic Search

In this paper, a comparative investigation of two forming-limit diagram (FLD) models based on the Swift and Hill instability criterion as well as on an empirical model proposed by the North American Deep Drawing Research Group (NADDRG) and experimental FLDs has been carried out for different mild and high-strength sheet steels, such as transformation-induced plasticity (TRIP), dual-phase (DP), austenitic stainless,

Wolfgang Bleck; Zhi Deng; Kostas Papamantellos; Christopher Oliver Gusek

1998-01-01

367

Limits for supersymmetry from a comprehensive study of CERN missing-energy events  

SciTech Connect

We have performed a comprehensive analysis of supersymmetric processes which can lead to missing-energy events such as those observed by the UA1 collaboration. Several critical aspects of the theoretical analysis are discussed here including fragmentation, backgrounds, and evolution of gluinos. When the experimentalists publish their final data, excellent limits will be set for M/sub g/ and M/sub q/, and it is possible that certain mass regions will not be excluded as explanations of the data.

Barnett, R.M.

1985-04-01

368

Green manure technology: Potential, usage, and limitations. A case study for lowland rice  

Microsoft Academic Search

\\u000a The growing concern about the sustainability of tropical agricultural systems stands in striking contrast to a world-wide\\u000a decline in the use of soil-improving legumes. It is timely to assess the future role that soil-improving legumes may play\\u000a in agricultural systems. This paper reviews recent progress, potential, and limitations of green manure technology, using\\u000a lowland rice cropping systems as the example.

M. Beckerl; J. K. Ladha; M. Ali

369

Environmental Impact of Mining and Ore Processing – A Case Study at Satellite Goldfields Limited  

Microsoft Academic Search

\\u000a The increasing number of surface mines in Ghana and the consequent adverse effects of mining operations on the environment\\u000a have been of great concern to the local communities, government and non-governmental organisations in Ghana over the last\\u000a decade. Satellite Goldfields Limited (SGL) is an open pit gold mine in the Mporhor Wassa East District which produces about\\u000a 10,000 tpd of

Albert O. Ainoo; Newton Amegbey; Raymond S. Suglo

370

Harmonizing human health studies in the Great Lakes.  

PubMed

Epidemiological studies of exposed human populations can provide valuable evidence of human health effects. Information has been sparse on human health effects associated with consumption of contaminated Great Lakes fish. As part of its Great Lakes Human Health Effects Research Program, the Agency for Toxic Substances and Disease Registry (ATSDR) has funded ten projects. Of these studies, eight are epidemiologic investigations of human exposure and potential health effects from consumption of contaminated fish. To strengthen and to enhance the findings and comparability across the health studies, ATSDR has initiated several activities. These activities include harmonizing questionnaires, analytical protocols, human health end points, and contaminants tested. Also included is the establishment of a quality assurance and quality control (QA/QC) program and tissue bank. These activities will allow ATSDR to enhance exposure assessment in the Great Lakes basin. In addition, these research activities allow ATSDR to evaluate and to interpret data across all the projects, including a basin-wide health risk analysis on exposure, levels of contaminants or body burden, and the potential for human health effects from exposure to Great Lakes contaminants. PMID:8843563

Hicks, H E; Spengler, R F

371

Pars Plana Vitrectomy and Internal Limiting Membrane Peeling for Macular Oedema Secondary to Retinal Vein Occlusion: a Pilot Study  

Microsoft Academic Search

Introduction: Macular oedema is the main cause of visual impairment following retinal vein occlusion. The purpose of this study was to evaluate the anatomical and functional outcome of pars plana vitrectomy and internal limited membrane (ILM) peeling for macular oedema secondary to retinal vein occlusion. Clinical Picture: This pilot study is a prospective non- randomised series of 11 eyes of

Xiao-Ling Liang; Hao-Yu Chen; Yong-Sheng Huang; Kah-Guan Au Eong; Shan-Shan Yu; Xing Liu

372

Duty-hour limits and patient care and resident outcomes: can high-quality studies offer insight into complex relationships?  

PubMed

Long hours are an accepted component of resident education, yet data suggest they contribute to fatigue that may compromise patient safety. A systematic review confirms that limiting duty hours increases residents' hours of sleep and improves objective measures of alertness. Most studies of operative experience for surgical residents found no effect, and there is evidence of a limited positive effect on residents' mood. We find a mixed effect on patient safety, although problems with supervision, rather than the limits, may be responsible or contibute; evidence of reduced continuity of care and reduced continuity in residents' clinical education; and evidence that increased workload under the limits has a negative effect on patient and resident outcomes. We highlight specific areas for research and offer recommendations for national policy. PMID:23121182

Philibert, Ingrid; Nasca, Thomas; Brigham, Timothy; Shapiro, Jane

2012-10-26

373

Epidemiological studies on radiation carcinogenesis in human populations following acute exposure: nuclear explosions and medical radiation.  

PubMed Central

The present review provides an understanding of our current knowledge of the carcinogenic effect of low-dose radiation in man, and surveys the epidemiological studies of human populations exposed to nuclear explosions and medical radiation. Discussion centers on the contributions of quantitative epidemiology to present knowledge, the reliability of the dose-incidence data, and those relevant epidemiological studies that provide the most useful information for risk estimation of cancer induction in man. Reference is made to dose-incidence relationships from laboratory animal experiments where they may obtain, for problems and difficulties in extrapolation from data obtained at high doses to low doses, and from animal data to the human situation. The paper describes the methods of application of such epidemiological data for estimation of excess risk of radiation-induced cancer in exposed human populations and discusses the strengths and limitations of epidemiology in guiding radiation protection philosophy and public health policy.

Fabrikant, J. I.

1981-01-01

374

Combined bidimensional electrophoresis and electron microscopy to study specific plasmid DNA replication intermediates in human cells.  

PubMed

Replication interference by specific chromosomal sequences-such as trinucleotide repeats-plays a causative, though undefined role in the aetiology of human disease, especially neurodegenerative syndromes. However, studies on these mechanisms in human cells have been hampered by poorly defined replication origins on genomic DNA. Simian Virus 40 (SV40)-based plasmids were useful in the past to overcome these experimental limits, but have been rarely amenable for the most complex and revealing molecular biology approaches to study in vivo DNA replication interference. This chapter describes a new, safe, SV40-based episomal system that replicates with very high efficiency in human cells and allows isolation of in vivo replication intermediates with high yield and purity. We describe how to use this experimental system to run preparative agarose 2D-gel and to extract specific replication intermediates to visualize by electron microscopy. PMID:24162990

Follonier, Cindy; Lopes, Massimo

2014-01-01

375

Lesson Study as a Human Science  

ERIC Educational Resources Information Center

Neither experimental nor design research in education is as well developed in Japan as in the United States. Yet Japanese educational practice employs a type of educational research called "lesson study" that is credited for instructional improvements, including the shift from "teaching as telling" to "teaching for understanding" in science and…

Lewis, Catherine C.; Akita, Kiyomi; Sato, Manabu

2010-01-01

376

Characterizing interspecies uncertainty using data from studies of anti-neoplastic agents in animals and humans  

SciTech Connect

For most chemicals, the Reference Dose (RfD) is based on data from animal testing. The uncertainty introduced by the use of animal models has been termed interspecies uncertainty. The magnitude of the differences between the toxicity of a chemical in humans and test animals and its uncertainty can be investigated by evaluating the inter-chemical variation in the ratios of the doses associated with similar toxicological endpoints in test animals and humans. This study performs such an evaluation on a data set of 64 anti-neoplastic drugs. The data set provides matched responses in humans and four species of test animals: mice, rats, monkeys, and dogs. While the data have a number of limitations, the data show that when the drugs are evaluated on a body weight basis: 1) toxicity generally increases with a species' body weight; however, humans are not always more sensitive than test animals; 2) the animal to human dose ratios were less than 10 for most, but not all, drugs; 3) the current practice of using data from multiple species when setting RfDs lowers the probability of having a large value for the ratio. These findings provide insight into inter-chemical variation in animal to human extrapolations and suggest the need for additional collection and analysis of matched toxicity data in humans and test animals.

Price, Paul S. [Dow Chemical Company, Toxicology and Environmental Research and Consulting, 1803 Building, Midland MI 48674 (United States)], E-mail: pprice@dow.com; Keenan, Russell E. [AMEC Earth and Environmental, 15 Franklin Street, Portland, ME 04101 (United States); Swartout, Jeffrey C. [National Center for Environmental Assessment U.S. Environmental Protection Agency, 26 W. M. L. King Drive, Cincinnati, OH 45268 (United States)

2008-11-15

377

Comparison of dietary analysis methods for human folate bioavailability studies  

Microsoft Academic Search

Accurate folate analysis of foods is essential for bioavailability studies. Direct folate analysis may be too labo- rious for large-scale studies and the current data on the folate content of Australian foods is limited. Can the UK food composition tables be substituted in the absence of Australian data? This study was performed in order to assess the validity of obtaining

AE de Ambrosis; J Arcot; J Paterson; AK Shrestha; P Haber

378

Impact of Design Trade Studies on System Human Resources.  

ERIC Educational Resources Information Center

|This study focused on two objectives. The first objective was to identify and classify the characteristics of conceptual design trade studies that have high potential impact on human resource requirements of Air Force weapon systems. The approach used was a case history review and analysis of 129 F-15 aircraft design trade studies. The analysis…

Whalen, Gary V.; Askren, William B.

379

Modified vaccinia virus Ankara undergoes limited replication in human cells and lacks several immunomodulatory proteins: implications for use as a human vaccine  

Microsoft Academic Search

Modified virus Ankara (MVA) is a vaccinia virus (VV) strain that was attenuated by serial passage through chick embryo fibroblasts (CEFs) and contains six large genomic deletions compared with parental virus. MVA replicates well in CEFs, but poorly in most mammalian cells. Recombinant MVA is a promising human vaccine candidate due to its restricted host range, immunogenicity and aviru- lence

Tom J. Blanchard; Antonio Alcami; Panayiota Andrea; Geoffrey L. Smith

380

Studying the Human– Computer–Terminology Interface  

Microsoft Academic Search

ObjectiveTo explore the use of an observational, cognitive-based approach for differentiating between successful, suboptimal, and failed entry of coded data by clinicians in actual practice, and to detect whether causes for unsuccessful attempts to capture true intended meaning were due to terminology content, terminology representation, or user interface problems.DesignObservational study with videotaping and subsequent coding of data entry events in

James J Cimino; Vimla L Patel; Andre W Kushniruk

2001-01-01

381

An analytical study of critical heat flux in a vertical channel with countercurrent flow limitation  

SciTech Connect

A quantitative analysis of critical heat flux (CHF) under countercurrent flow limitation (CCFL) or flooding was successfully carried out using the existing experimental results for vertical circular, rectangular, and annual channels, applying the criteria, proposed by the author, that the CCFL condition could be determined by maximizing the water mass flux falling down in the vertical channels with respect to the water film thickness and a model of dryout of water filmflow at the CHF point. It was clarified that the analytical results give good predictions of the existing experimental results of vertical channels, identifying the factors determining the CHF under CCFL conditions.

Sudo, Yukio

1995-10-01

382

Pilot studies of superfractionated radiotherapy and combination chemotherapy in limited oat cell carcinoma of the bronchus  

SciTech Connect

There are sound radiobiologic and suggestive clinical rationale for superfractionating the radiotherapeutic regimens employed for the therapy of rapidly growing malignancies. Oat cell carcinoma of the bronchus is such a tumor. The authors report their experience combining aggressive systemic combination chemotherapy with supperfractionated radiotherapy for the treatment of limited oat cell carcinoma of the bronchus. Overall, patient tolerance was satisfactory and a complete remission rate of 74% was achieved. It remains to be proven, in a prospective randomized fashion, whether this approach is superior to current conventional management.

Hodson, D.I.; Malaker, K.; Meikle, A.L.; Levitt, M.

1984-10-01

383

Brain activity and human unilateral chewing: an FMRI study.  

PubMed

Brain mechanisms underlying mastication have been studied in non-human mammals but less so in humans. We used functional magnetic resonance imaging (fMRI) to evaluate brain activity in humans during gum chewing. Chewing was associated with activations in the cerebellum, motor cortex and caudate, cingulate, and brainstem. We also divided the 25-second chew-blocks into 5 segments of equal 5-second durations and evaluated activations within and between each of the 5 segments. This analysis revealed activation clusters unique to the initial segment, which may indicate brain regions involved with initiating chewing. Several clusters were uniquely activated during the last segment as well, which may represent brain regions involved with anticipatory or motor events associated with the end of the chew-block. In conclusion, this study provided evidence for specific brain areas associated with chewing in humans and demonstrated that brain activation patterns may dynamically change over the course of chewing sequences. PMID:23103631

Quintero, A; Ichesco, E; Myers, C; Schutt, R; Gerstner, G E

2012-10-26

384

Ischemic preconditioning induces autophagy and limits necrosis in human recipients of fatty liver grafts, decreasing the incidence of rejection episodes  

PubMed Central

Whether ischemic preconditioning (IP) reduces ischemia/reperfusion (I/R) injury in human normal and fatty livers remains controversial. We compared two independent groups of liver donor transplants with versus without steatosis to evaluate IP consequences. Liver donors with (n=22) or without (n=28) steatosis either did or did not undergo IP before graft retrieval. Clinical data from the recipients, as well as histological and immunohistological characteristics of post-reperfusion biopsies were analyzed. Incidence of post-reperfusion necrosis was increased (10/10 versus 9/14, respectively; P<0.05) and the clinical outcome of recipients was worse for non-IP steatotic liver grafts compared with non-IP non-steatotic grafts. IP significantly lowered the transaminase values only in patients receiving a non-steatotic liver. An increased expression of beclin-1 and LC3, two pro-autophagic proteins, tended to decrease the incidence of necrosis (P=0.067) in IP steatotic livers compared with non-IP steatotic group. IP decreased the incidence of acute and chronic rejection episodes in steatotic livers (2/12 versus 6/10; P=0.07 and 2/12 versus 7/10; P<0.05, respectively), but not in non-steatotic livers. Thus, IP may induce autophagy in human steatotic liver grafts and reduce rejection in their recipients.

Degli Esposti, D; Sebagh, M; Pham, P; Reffas, M; Pous, C; Brenner, C; Azoulay, D; Lemoine, A

2011-01-01

385

Cannabis and psychosis/schizophrenia: human studies  

PubMed Central

The association between cannabis use and psychosis has long been recognized. Recent advances in knowledge about cannabinoid receptor function have renewed interest in this association. Converging lines of evidence suggest that cannabinoids can produce a full range of transient schizophrenia-like positive, negative, and cognitive symptoms in some healthy individuals. Also clear is that in individuals with an established psychotic disorder, cannabinoids can exacerbate symptoms, trigger relapse, and have negative consequences on the course of the illness. The mechanisms by which cannabinoids produce transient psychotic symptoms, while unclear may involve dopamine, GABA, and glutamate neurotransmission. However, only a very small proportion of the general population exposed to cannabinoids develop a psychotic illness. It is likely that cannabis exposure is a “component cause” that interacts with other factors to “cause” schizophrenia or a psychotic disorder, but is neither necessary nor sufficient to do so alone. Nevertheless, in the absence of known causes of schizophrenia, the role of component causes remains important and warrants further study. Dose, duration of exposure, and the age of first exposure to cannabinoids may be important factors, and genetic factors that interact with cannabinoid exposure to moderate or amplify the risk of a psychotic disorder are beginning to be elucidated. The mechanisms by which exposure to cannabinoids increase the risk for developing a psychotic disorder are unknown. However, novel hypotheses including the role of cannabinoids on neurodevelopmental processes relevant to psychotic disorders are being studied.

Sewell, Richard Andrew; Ranganathan, Mohini

2010-01-01

386

Limitations in the use of race in the study of disease causation.  

PubMed Central

Tremendous variation exists in the rates of many chronic diseases across racial groups. However, serious technical and conceptual limitations hamper the ability of racial comparisons to illuminate the causative pathways. First, race is confounded by social class, which is complex, and like other confounders of race, may not be measured with equal validity across racial groups. Second, statistical "adjustments" for race effects can be misleading since residual confounding may be misconstrued as a genetic effect. Third, the biologic concept of race tempts us to ignore the context dependency of genetic expression. When trying to detect genetic effects, both the environmental and genetic contributions must be measured and potential gene-environment interactions accounted for. Unfortunately, this process is beyond our current technical capabilities. To move forward on the problem of prostate cancer and other diseases distinguished by marked ethnic differentials, investigators need a more comprehensive understanding of the factors that mediate the apparent effect of race combined with valid measures of those factors, as well as novel strategies that can help overcome the technical and interpretive limitations of statistical adjustment. Finally, the "grand" theories of race-based genetic susceptibility must be replaced with rigorous criteria to determine when a trait can be ascribed to some genetic origin.

Cooper, R. S.; Freeman, V. L.

1999-01-01

387

Rate-limited electroless gold thin film growth: a real-time study.  

PubMed

Time-resolved, in situ spectroscopy of electroless (EL) gold (Au) films combined with electron microscopy showed that the deposition rate increased up to two-fold on surfaces swept by the bulk flow of adjacent fluid at Reynolds numbers less than 1.0, compared to batch immersion. Deposition rates from 5.0 to 9.0 nm/min and thicknesses of the EL Au film from 20 to 100 nm, respectively, increased predictably with flow rate at conditions when the deposition was limited primarily by Fickian diffusion. Time-frames were identified for metal island nucleation, growth, and subsequent film development during EL Au deposition by real-time UV-visible spectroscopy of photoluminescence (PL) and surface plasmon features of nanoscale metal deposits. Film thicknesses measured by scanning electron microscopy and X-ray photoelectron spectroscopy paired with real-time optical spectroscopy of kinetic aspects of plasmon and PL optical features indicated that Au film deposition on surfaces swept by a steady flow of adjacent fluid can be primarily diffusion limited. PMID:23560793

Jang, Gyoung Gug; Blake, Phillip; Roper, D Keith

2013-04-23

388

Prospective study on stereotactic radiotherapy of limited-stage non-small-cell lung cancer  

SciTech Connect

Purpose: To test the effect of stereotactic body radiotherapy (SBRT) in the treatment of medically inoperable patients with limited-stage non-small-cell lung cancer (NSCLC) in a Phase II trial. Methods and Materials: Forty patients with Stage I NSCLC were treated with SBRT with a central dose of 15 Gy x 3 within 5-8 days. Results: Eight patients (20%) obtained a complete response, 15 (38%) had a partial response, and 12 (30%) had no change or could not be evaluated. Only 3 patients had a local recurrence, and the local control rate 2 years after SBRT was 85%. At 2 years, 54% were without local or distant progression, and overall survival was 47%. Within 6 months after treatment, one or more Grade {>=}2 reactions were observed in 48% of the patients. Conclusions: Stereotactic body radiotherapy in patients with limited-stage NSCLC resulted in a high probability of local control and a promising survival rate. The toxicity after SBRT of lung tumors was moderate. However, deterioration in performance status, respiratory insufficiency, and other side effects were observed.

Hoyer, Morten [Department of Oncology, Aarhus University Hospital, Aarhus (Denmark)]. E-mail: hoyer@as.aaa.dk; Roed, Henrik D. [Department of Radiation Oncology, Copenhagen University Hospital, Copenhagen (Denmark); Hansen, Anders Traberg [Department of Medical Physics, Aarhus University Hospital, Aarhus (Denmark); Ohlhuis, Lars [Department of Radiation Oncology, Copenhagen University Hospital, Copenhagen (Denmark); Petersen, Jorgen [Department of Medical Physics, Aarhus University Hospital, Aarhus (Denmark); Nellemann, Hanne [Department of Radiology, Aarhus University Hospital, Aarhus (Denmark); Berthelsen, Anne Kiil [Department of Radiation Oncology, Copenhagen University Hospital, Copenhagen (Denmark); Grau, Cai D. [Department of Oncology, Aarhus University Hospital, Aarhus (Denmark); Engelholm, Svend Aage D. [Department of Radiation Oncology, Copenhagen University Hospital, Copenhagen (Denmark); Maase, Hans D. von der [Department of Oncology, Aarhus University Hospital, Aarhus (Denmark)

2006-11-15

389

Biological control of plant pathogens: advantages and limitations seen through the case study of Pythium oligandrum.  

PubMed

The management of certain plant beneficial microorganisms [biological control agents (BCAs)] seems to be a promising and environmental friendly method to control plant pathogens. However, applications are still limited because of the lack of consistency of BCAs when they are applied in the field. In the present paper, the advantages and limitations of BCAs are seen through the example of Pythium oligandrum, an oomycete that has received much attention in the last decade. The biological control exerted by P. oligandrum is the result of a complex process, which includes direct effects through the control of pathogens and/or indirect effects mediated by P. oligandrum, i.e. induction of resistance and growth promotion. P. oligandrum antagonism is a multifaceted and target fungus-dependent process. Interestingly, it does not seem to disrupt microflora biodiversity on the roots. P. oligandrum has an atypical relationship with the plant because it rapidly penetrates into the root tissues but it cannot stay alive in planta. After root colonisation, because of the elicitation by P. oligandrum of the plant-defence system, plants are protected from a range of pathogens. The management of BCAs, here P. oligandrum, is discussed with regard to its interactions with the incredibly complex agrosystems. PMID:23695856

Gerbore, J; Benhamou, N; Vallance, J; Le Floch, G; Grizard, D; Regnault-Roger, C; Rey, P

2013-05-22

390

Interaction of pentylsarin analogues with human acetylcholinesterase: A kinetic study  

Microsoft Academic Search

Previous kinetic studies investigating the interactions between human acetylcholinesterase (AChE), structurally different organophosphorus compounds (OP) and oximes did not reveal a conclusive structure–activity relationship of the different reactions. The only exception was for a homologous series of methylphosphonofluoridates bearing C1–C4 O-n- or O-i-alkyl residues. Hence, it was tempting to investigate the kinetic interactions between different pentylsarin analogues, human AChE and

F. Worek; N. M. Herkert; M. Koller; N. Aurbek; H. Thiermann

2009-01-01

391

Human factors and cardiac surgery: A multicenter study  

Microsoft Academic Search

Objective: To study the role of human factors on surgical outcomes, with a series of 243 arterial switch operations performed by 21 surgeons taken as a model. Methods: The following data were collected: patient-specific and procedural variables, self-assessment questionnaires, and a written report from a human factors researcher who observed the operation. The relationship of patient-specific variables to outcomes (death

Marc R. de Leval; Jane Carthey; David J. Wright; Vernon T. Farewell; James T. Reason

2000-01-01

392

Studies on the nucleic acid of human bladder carcinoma.  

PubMed

DNA was isolated from different histopathologic types and grades of human bladder carcinoma. The isolated DNA was submitted to quantitative determination and base composition analysis. A pilot study was done on the effect of gamma irradiation as a physical mutagen on characteristics of DNA in the examined tissues. Identity in the genetic components in the urinary bilharziasis snails and the human bladder cancer was observed. The same was observed in both intestinal bilharziasis snails and the cancerous intestinal tissues. PMID:2121361

Nabih, I; Mantawy, M M; Abdel-Hamid, A Z

1990-01-01

393

Determination of ibudilast in human serum by high-performance liquid chromatography for pharmacokinetic study.  

PubMed

A simple, accurate, precise and cost effective reversed-phase HPLC method was developed to determine the concentration of ibudilast in human serum. Ibudilast and an internal standard, butyl 4-hydroxybenzoate, were extracted by liquid-liquid extraction with methyl tert-butyl ether. HPLC analysis was carried out under the following conditions: a Luna C(18)(2) 5 microm column, a mobile phase of acetonitrile-0.02% phosphoric acid (50 : 50, v/v, adjusted to pH 6.0 with triethylamine) and a UV detector at 319 nm. The chromatograms showed good resolution and sensitivity as well as no interference from the human serum. The calibration curves were linear over the concentration range, 1-100 ng/mL, for serum with correlation coefficients >0.999. The intra- and inter-day assay precision as well as the accuracy fulfilled the international requirements. The mean absolute recovery for human serum was 101.7 +/- 6.1%. The lower limit of quantitation in human serum was 1 ng/mL, which is sensitive enough for pharmacokinetic studies. Stability studies revealed that ibudilast in human serum was stable during storage as well as during the assay procedure. This method was applied successfully to an examination of the pharmacokinetics of ibudilast in human subjects following a single oral dose of an ibudilast (10 mg) capsule. PMID:19629961

Yoon, Hwa; Cho, Hea-Young; Lee, Yong-Bok

2010-03-01

394

Microvascular studies in human radiation bowel disease.  

PubMed Central

The microvasculature was investigated in the normal bowel (n = 43 patients) and in radiation bowel disease (n = 18 patients). Tissue samples obtained from postoperative colectomy specimens in which the intramural vessels had been perfused with barium sulphate suspension were examined. Microradiography was used to study vascular pattern which was abnormal in radiation bowel disease. A recently described radiograph fluorescence system was used to estimate barium concentration, and hence microvascular volume. The radiation group showed a highly significant reduction in barium concentration (p less than 0.001), when compared with the normal group. This reduction was diffuse in samples from 15 patients who had received combined intracavity and external radiotherapy, but localised in two patients who had received intracavity treatment only. It is concluded that microvascular compromise is an important factor in the natural history of radiation bowel disease. Images Fig. 1 Fig. 2 Fig. 3 Fig. 4

Carr, N D; Pullen, B R; Hasleton, P S; Schofield, P F

1984-01-01

395

Experimental study of lean flammability limits of methane/hydrogen/air mixtures in tubes of different diameters  

SciTech Connect

Lean limit flames in methane/hydrogen/air mixtures propagating in tubes of internal diameters (ID) of 6.0, 8.9, 12.3, 18.4, 25.2, 35.0, and 50.2 mm have been experimentally studied. The flames propagated upward from the open bottom end of the tube to the closed upper end. The content of hydrogen in the fuel gas has been varied in the range 0-40 mol%. Lean flammability limits have been determined; flame shapes recorded and the visible speed of flame propagation measured. Most of the observed limit flames in tubes with diameters in the range of 8.9-18.4 mm had enclosed shape, and could be characterized as distorted or spherical flame balls. The tendency was observed for mixtures with higher hydrogen content to form smaller size, more uniform flame balls in a wider range of tube diameters. At hydrogen content of 20% or more in the fuel gas, limit flames in largest diameters (35.0 mm and 50.2 mm ID) tubes had small, compared to the tube diameter, size and were ''lens''-shaped. ''Regular'' open-front lean limit flames were observed only for the smallest diameters (6.0 mm and 8.9 mm) and largest diameters (35.0 and 50.2 mm ID), and only for methane/air and (90% CH{sub 4} + 10% H{sub 2})/air mixtures, except for 6 mm ID tube in which all limit flames had open front. In all experiments, except for the lean limit flames in methane/air and (90% CH{sub 4} + 10% H{sub 2})/air mixtures in the 8.9 mm ID tube, and all limit flames in 6.0 mm ID tube, visible flame speeds very weakly depended on the hydrogen content in the fuel gas and were close to- or below the theoretical estimate of the speed of a rising hot bubble. This observation suggests that the buoyancy is the major factor which determines the visible flame speed for studied limit flames, except that last mentioned. A decrease of the lean flammability limit value with decreasing the tube diameter was observed for methane/air and (90% CH{sub 4} + 10% H{sub 2})/air mixtures for tubes having internal diameters in the range of 18.4-50.2 mm. This effect has been attributed to the stronger combined effect of the preferential diffusion and flame stretch in narrower tubes for flames which resemble rising bubble. (author)

Shoshin, Y.L.; Goey, L.P.H. de [Eindhoven University of Technology, Mechanical Engineering, Eindhoven (Netherlands)

2010-04-15

396

Human Ovarian Tumor Cells Escape gammadelta T Cell Recognition Partly by Down Regulating Surface Expression of MICA and Limiting Cell Cycle Related Molecules  

Microsoft Academic Search

BackgroundMechanisms of human V?2V?2 T cell-mediated tumor immunity have yet to be fully elucidated.Methods and FindingsAt least some tumor cell recognition is mediated by NKG2D-MICA interactions. Herein, by using MTT assay and PI-BrdU co-staining and Western-blot, we show that these V?2V?2 T cells can limit the proliferation of ovarian tumor cells by down regulation of apoptosis and cell cycle related

Jingwei Lu; Reeva Aggarwal; Suman Kanji; Manjusri Das; Matthew Joseph; Vincent Pompili; Hiranmoy Das; Rakesh K. Srivastava

2011-01-01

397

A comparative study of limited-angle cone-beam reconstruction methods for breast tomosynthesis  

SciTech Connect

Digital tomosynthesis mammography (DTM) is a promising new modality for breast cancer detection. In DTM, projection-view images are acquired at a limited number of angles over a limited angular range and the imaged volume is reconstructed from the two-dimensional projections, thus providing three-dimensional structural information of the breast tissue. In this work, we investigated three representative reconstruction methods for this limited-angle cone-beam tomographic problem, including the backprojection (BP) method, the simultaneous algebraic reconstruction technique (SART) and the maximum likelihood method with the convex algorithm (ML-convex). The SART and ML-convex methods were both initialized with BP results to achieve efficient reconstruction. A second generation GE prototype tomosynthesis mammography system with a stationary digital detector was used for image acquisition. Projection-view images were acquired from 21 angles in 3 deg. increments over a {+-}30 deg. angular range. We used an American College of Radiology phantom and designed three additional phantoms to evaluate the image quality and reconstruction artifacts. In addition to visual comparison of the reconstructed images of different phantom sets, we employed the contrast-to-noise ratio (CNR), a line profile of features, an artifact spread function (ASF), a relative noise power spectrum (NPS), and a line object spread function (LOSF) to quantitatively evaluate the reconstruction results. It was found that for the phantoms with homogeneous background, the BP method resulted in less noisy tomosynthesized images and higher CNR values for masses than the SART and ML-convex methods. However, the two iterative methods provided greater contrast enhancement for both masses and calcification, sharper LOSF, and reduced interplane blurring and artifacts with better ASF behaviors for masses. For a contrast-detail phantom with heterogeneous tissue-mimicking background, the BP method had strong blurring artifacts along the x-ray source motion direction that obscured the contrast-detail objects, while the other two methods can remove the superimposed breast structures and significantly improve object conspicuity. With a properly selected relaxation parameter, the SART method with one iteration can provide tomosynthesized images comparable to those obtained from the ML-convex method with seven iterations, when BP results were used as initialization for both methods.

Zhang Yiheng; Chan, H.-P.; Sahiner, Berkman; Wei, Jun; Goodsitt, Mitchell M.; Hadjiiski, Lubomir M.; Ge Jun; Zhou Chuan [Department of Radiology, University of Michigan, Ann Arbor, Michigan 48109-0904 (United States)

2006-10-15

398

HUMEX, a study on the survivability and adaptation of humans to long-duration exploratory missions, part II: Missions to Mars  

Microsoft Academic Search

Space exploration programmes, currently under discussion in the US and in Europe, foresee human missions to Mars to happen within the first half of this century. In this context, the European Space Agency (ESA) has conducted a study on the human responses, limits and needs for such exploratory missions, the so-called HUMEX study (ESA SP-1264). Based on a critical assessment

G. Horneck; R. Facius; M. Reichert; P. Rettberg; W. Seboldt; D. Manzey; B. Comet; A. Maillet; H. Preiss; L. Schauer; C. G. Dussap; L. Poughon; A. Belyavin; G. Reitz; C. Baumstark-Khan; R. Gerzer

2006-01-01

399

Acute effects of steroid hormones and neuropeptides on human social-emotional behavior: a review of single administration studies.  

PubMed

Steroids and peptides mediate a diverse array of animal social behaviors. Human research is restricted by technical-ethical limitations, and models of the neuroendocrine regulation of social-emotional behavior are therefore mainly limited to non-human species, often under the assumption that human social-emotional behavior is emancipated from hormonal control. Development of acute hormone administration procedures in human research, together with the advent of novel non-invasive neuroimaging techniques, have opened up opportunities to systematically study the neuroendocrinology of human social-emotional behavior. Here, we review all placebo-controlled single hormone administration studies addressing human social-emotional behavior, involving the steroids testosterone and estradiol, and the peptides oxytocin and vasopressin. These studies demonstrate substantial hormonal control over human social-emotional behavior and give insights into the underlying neural mechanisms. Finally, we propose a theoretical model that synthesizes detailed knowledge of the neuroendocrinology of social-emotional behavior in animals with the recently gained data from humans described in our review. PMID:21256859

Bos, Peter A; Panksepp, Jaak; Bluthé, Rose-Marie; van Honk, Jack

2011-01-21

400

Atom-dimer scattering length for fermions with different masses: Analytical study of limiting cases  

NASA Astrophysics Data System (ADS)

We consider the problem of obtaining the scattering length for a fermion colliding with a dimer, formed from a fermion identical to the incident one and another different fermion. This is done in the universal regime where the range of interactions is short enough that the scattering length a for nonidentical fermions is the only relevant quantity. This is the generalization to fermions with different masses of the problem solved long ago by Skorniakov and Ter-Martirosian for particles with equal masses. We solve this problem analytically in the two limiting cases where the mass of the solitary fermion is very large or very small compared to the mass of the two other identical fermions. This is done for both the value of the scattering length and the function entering the Skorniakov-Ter-Martirosian integral equation, for which simple explicit expressions are obtained.

Alzetto, F.; Combescot, R.; Leyronas, X.

2010-12-01

401

Assessment study of superconducting fault-current limiters operating at 77K  

SciTech Connect

The possible impact of nitrogen-cooled superconductors on the design and cost of superconducting fault-current limiters is assessed by considering the technical specifications such devices must meet and by comparing material properties of 77-K and 4-K superconductors. The main advantage of operating superconductors at 77 K is that the refrigeration operating cost is reduced by a factor of up to 25, and the refrigeration capital cost is reduced by a factor of up to 10. The heat capacity of 77 K is several orders of magnitude larger than at 4 K. This phenomenon increases conductor stability against flux jumps but makes switching from the superconducting to normal state slow and difficult. Consequently, a high critical current density, probably at least 10{sup 5} A/cm{sup 2}, is required.

Giese, R.F. (Argonne National Lab., IL (United States)); Runde, M. (Energiforsyningens Forskningsinstitutt A/S, Trondheim (Norway))

1992-01-01

402

Assessment study of superconducting fault-current limiters operating at 77K  

SciTech Connect

The possible impact of nitrogen-cooled superconductors on the design and cost of superconducting fault-current limiters is assessed by considering the technical specifications such devices must meet and by comparing material properties of 77-K and 4-K superconductors. The main advantage of operating superconductors at 77 K is that the refrigeration operating cost is reduced by a factor of up to 25, and the refrigeration capital cost is reduced by a factor of up to 10. The heat capacity of 77 K is several orders of magnitude larger than at 4 K. This phenomenon increases conductor stability against flux jumps but makes switching from the superconducting to normal state slow and difficult. Consequently, a high critical current density, probably at least 10{sup 5} A/cm{sup 2}, is required.

Giese, R.F. [Argonne National Lab., IL (United States); Runde, M. [Energiforsyningens Forskningsinstitutt A/S, Trondheim (Norway)

1992-07-01

403

Three-dimensional reconstruction from limited biplane angiographic projections: a phantom study  

NASA Astrophysics Data System (ADS)

A method for 3D cone beam reconstruction of cerebral vasculature (both morphology and grayscale) from a limited number (less than 10) of digital subtraction angiographic (DSA) projections obtained with a standard biplane C-arm x-ray system is described. The reconstruction method includes geometric calibration of the source and detector orientation, spatial image distortion correction, and algebraic reconstruction technique (ART) with non- negativity constraint. Accuracy of voxel gray scale values estimated by ART is enhanced by determination of weights based on the intersection volume between a pyramidal ray and cubic voxel. The reconstruction is accelerated by retaining only the vessel containing voxels and distributed computing. Reconstruction of a phantom containing fiducial markers at known 3D locations demonstrated that the reconstructed geometry is accurate to less than a pixel width. Reconstruction is also obtained from an anatomic skull phantom with an embedded cerebral vasculature reproduction that includes an aneurysm. Three dimensional reconstruction exhibited the necessary details, both structural and grayscale.

Sen, Anindya; Hsiung, Hsiang-Hsin; Schueler, Beth A.; Latchaw, Richard E.; Hu, Xiaoping

1996-04-01

404

Acute, subacute and long-term subjective effects of psilocybin in healthy humans: a pooled analysis of experimental studies  

Microsoft Academic Search

Psilocybin and related hallucinogenic compounds are increasingly used in human research. However, due to limited information about potential subjective side effects, the controlled medical use of these compounds has remained controversial. We therefore analysed acute, short- and long-term subjective effects of psilocybin in healthy humans by pooling raw data from eight double-blind placebo-controlled experimental studies conducted between 1999 and 2008.

Erich Studerus; Michael Kometer; Felix Hasler; Franz X Vollenweider

2011-01-01

405

The human hepatoma HepaRG cells: A highly differentiated model for studies of liver metabolism and toxicity of xenobiotics  

Microsoft Academic Search

Although they have several important limitations primary human hepatocytes still represent the in vitro gold standard model for xenobiotic metabolism and toxicity studies. The large use of human liver cell lines either from tumoral origin or obtained by oncogenic immortalisation is prevented by the loss of various liver-specific functions, especially many cytochrome P450 (CYP)-related enzyme activities. We review here recent

André Guillouzo; Anne Corlu; Caroline Aninat; Denise Glaise; Fabrice Morel; Christiane Guguen-Guillouzo

2007-01-01

406

Kansas Populism, Woman Suffrage, and the Agrarian Myth: A Case Study in the Limits of Mythic Transcendence.  

ERIC Educational Resources Information Center

|Describes the success of the Populist movement in the 1890s, arguing that it provides a case study of the power and limitations of mythic appeals to transcend diverse political ideologies. Argues that Populist extensions of the agrarian myth to encompass industrial laborers, suffragists, and prohibitionists were motivated by political expediency.…

Burkholder, Thomas R.

1989-01-01

407

A Study of the Reliability, Validity, and Precision of Scales to Measure Chronic Functional Limitations Due to Poor Health.  

National Technical Information Service (NTIS)

Results of psychometric studies of 14 questionnaire items commonly used to define chronic functional limitations due to poor health are reported. Self-administered questionnaires were used to gather data from 1,209 persons 14 years of age and older. Data ...

A. L. Stewart J. E. Ware R. H. Brook

1977-01-01

408

Instant Active Dry Yeast Project. Republic of South Africa Feasibility Study Report for Expectra Pty Limited (Public Version).  

National Technical Information Service (NTIS)

Expectra Pty Limited ('Expectra'), a South African company and the sponsor of the project and this Feasibility Study has plans to construct a new Instant Active Dry Yeast (IADY) ad wet yeast plant in South Africa and market the product to the local market...

2004-01-01

409

Energy Engineering Analysis Program, Limited Energy Study of Steam Distribution Systems, Hawthorne Army Ammunition Depot, Hawthorne, Nevada.  

National Technical Information Service (NTIS)

This report summarizes all work of the Limited Energy Study of Steam Distribution Systems, Energy Engineering Analysis Program, Hawthorne Army Ammunition Depot (HWAAD), Nevada. The project is authorized under Contract No. DACA05-92-C-0155 with the U.S. Ar...

1995-01-01

410

Study of limiter damage in a magnetic-field error region of the ZT-40M experiment  

SciTech Connect

A study has been initiated of material plasma interactions on the ZT-40M, Reversed Field Pinch (RFP) plasma physics confinement experiment at Los Alamos National Laboratory. Observations of the evaporation and cracking to TiC coatings, initially placed on an AXF-5Q Graphite mushroom limiter, installed in a high field error region (e.g. an experimental vacuum vessel/liner port) were investigated. A parametric study was performed of the thermal and stress behavior of the limiter and coating materials undergoing plasma material heat exchange processes, in order to infer the magnitude of heat flux necessary to explain the observed material damage. In addition the vacuum (liner) wall material behavior was studied parametrically using the same heat flux values as the limiter study. A one-dimensional conduction model was used with applied heat and radiation boundary conditions, for predicting temperature distributions in space and time, where the thermal stress was calculated using a restrained in bending only plate model. Wall loadings corresponding to first wall, limiter energy fluxes ranging between 1 x 10/sup 2/ W/cm/sup 2/ and 1 x 10/sup 5/ W/cm/sup 2/ were used as parameters with plasma material interaction times (tau/sub QO) between 0.5 ms and 10 ms. Short plasma energy deposition time (tau/sub QO/ > 10 ms) spacial and time histories of temperature and stress were calculated for SS-304, Inconel-625, TiC and AXF -5Q Graphite materials.

Makowitz, H.

1983-01-01

411

Prospects: The Congressionally Mandated Study of Educational Growth and Opportunity. Final Report on Limited English Proficient Students.  

ERIC Educational Resources Information Center

|As a reflection of the importance attached to successfully educating children whose native language is not English, the U.S. Department of Education's longitudinal study of Chapter 1 assistance, "Prospects," includes a component devoted to the analysis of limited-English-proficient (LEP) students. Chapter 1, renamed Title 1 in 1994, is the…

Buron, Lawrence; Beecroft, Erik; Bell, Stephen; Price, Cristofer; Gemmen, Eric

412

A Study of Suburban Secondary Education Mathematics Programs: The Programmatic Impact of Limited Early Access to Algebra on Student Performance  

ERIC Educational Resources Information Center

|The purpose of this researcher was to investigate the programmatic impact of school districts' practice of limited early access to algebra on student performance. School districts selected for the study are located in the counties of Nassau and Suffolk, Long Island, New York. School districts that reported Mathematics A and Integrated Algebra…

Watkins, Donna Moguel

2010-01-01

413

Human Security as Global Security: Reconceptualising Strategic Studies  

Microsoft Academic Search

The article argues that global security should be seen as synonymous with human security, and that strategic studies should be located within that broader rubric. Mounting such an argument means meeting the charge of those who see the broader construction of strategic studies as vague and meaningless, and as detracting from the ability to make good policy. The article attempts,

Ralph Pettman

2005-01-01

414

Ecology and Human Values: A Course of Study. (Working Draft).  

ERIC Educational Resources Information Center

|This interdisciplinary course is designed for senior year high school students in social studies and/or science. Its main thrust is the investigation of human values as they relate to the environment, although rooted in the natural sciences as a means of understanding the complexities inherent in the environment. Use is made of the case study

Wisconsin State Dept. of Public Instruction, Madison.

415

B-1B Human Factors Baseline Study Report.  

National Technical Information Service (NTIS)

A Human Factors study was conducted on B-1B Blocks D, E, and F. The 1st study objective was to evaluate B-1B Blocks D, E, and F crew workload and situational awareness. The 2nd objective was to establish a measurable crew performance baseline for future B...

W. G. Kalman J. M. Kline S. Provost B. A. Gable C. R. Taylor

1999-01-01

416

Human Readable Machine Readable Information Processor Conceptual Study and Design.  

National Technical Information Service (NTIS)

This report presents the results of the second part of a two-part study program for the conceptual development and design study of a Human Readable Machine Readable Information Processor that uses the Committee on Scientific and Technical Information (COS...

J. S. Montouri F. A. Slaker L. D. Thorp P. G. Engeldrum J. S. Lemoine

1971-01-01

417

Mysid Population Responses to Resource Limitation Differ from those Predicted by Cohort Studies  

EPA Science Inventory

Effects of anthropogenic stressors on animal populations are often evaluated by assembling vital rate responses from isolated cohort studies into a single demographic model. However, models constructed from cohort studies are difficult to translate into ecological predictions be...

418

The Benefits of Humanized Yeast Models to Study Parkinson's Disease  

PubMed Central

Over the past decade, the baker's yeast Saccharomyces cerevisiae has proven to be a useful model system to investigate fundamental questions concerning the pathogenic role of human proteins in neurodegenerative diseases such as Parkinson's disease (PD). These so-called humanized yeast models for PD initially focused on ?-synuclein, which plays a key role in the etiology of PD. Upon expression of this human protein in the baker's yeast Saccharomyces cerevisiae, the events leading to aggregation and the molecular mechanisms that result in cellular toxicity are faithfully reproduced. More recently, a similar model to study the presumed pathobiology of the ?-synuclein interaction partner synphilin-1 has been established. In this review we will discuss recent advances using these humanized yeast models, pointing to new roles for cell wall integrity signaling, Ca2+ homeostasis, mitophagy, and the cytoskeleton.

Franssens, V.; Bynens, T.; Van den Brande, J.; Vandermeeren, K.; Verduyckt, M.; Winderickx, J.

2013-01-01

419

The benefits of humanized yeast models to study Parkinson's disease.  

PubMed

Over the past decade, the baker's yeast Saccharomyces cerevisiae has proven to be a useful model system to investigate fundamental questions concerning the pathogenic role of human proteins in neurodegenerative diseases such as Parkinson's disease (PD). These so-called humanized yeast models for PD initially focused on ? -synuclein, which plays a key role in the etiology of PD. Upon expression of this human protein in the baker's yeast Saccharomyces cerevisiae, the events leading to aggregation and the molecular mechanisms that result in cellular toxicity are faithfully reproduced. More recently, a similar model to study the presumed pathobiology of the ? -synuclein interaction partner synphilin-1 has been established. In this review we will discuss recent advances using these humanized yeast models, pointing to new roles for cell wall integrity signaling, Ca(2+) homeostasis, mitophagy, and the cytoskeleton. PMID:23936613

Franssens, V; Bynens, T; Van den Brande, J; Vandermeeren, K; Verduyckt, M; Winderickx, J

2013-07-01

420

The relationship between type 2 diabetes and cognitive dysfunction: longitudinal studies and their methodological limitations  

Microsoft Academic Search

Type 2 diabetes and dementia in the elderly are major public health problems. Cross-sectional studies have suggested that these two conditions may be inter-related, but the nature of this association is uncertain. Causation can only be established through studies with a longitudinal design, taking into account the many potential confounding factors in any study of cognition. A literature search has

Kate V. Allen; Brian M. Frier; Mark W. J. Strachan

2004-01-01

421

Ontology-Based Federated Data Access to Human Studies Information  

PubMed Central

Human studies are one of the most valuable sources of knowledge in biomedical research, but data about their design and results are currently widely dispersed in siloed systems. Federation of these data is needed to facilitate large-scale data analysis to realize the goals of evidence-based medicine. The Human Studies Database project has developed an informatics infrastructure for federated query of human studies databases, using a generalizable approach to ontology-based data access. Our approach has three main components. First, the Ontology of Clinical Research (OCRe) provides the reference semantics. Second, a data model, automatically derived from OCRe into XSD, maintains semantic synchrony of the underlying representations while facilitating data acquisition using common XML technologies. Finally, the Query Integrator issues queries distributed over the data, OCRe, and other ontologies such as SNOMED in BioPortal. We report on a demonstration of this infrastructure on data acquired from institutional systems and from ClinicalTrials.gov.

Sim, Ida; Carini, Simona; Tu, Samson W.; Detwiler, Landon T.; Brinkley, James; Mollah, Shamim A.; Burke, Karl; Lehmann, Harold P.; Chakraborty, Swati; Wittkowski, Knut M.; Pollock, Brad H.; Johnson, Thomas M.; Huser, Vojtech

2012-01-01

422

Isolation of a new human fetal liver cytochrome P450 cDNA clone: evidence for expression of a limited number of forms of cytochrome P450 in human fetal livers.  

PubMed

From a human fetal liver cDNA library, a new cDNA clone (lambda HFL10) was isolated using an antiserum to P450 HFLa, which has been isolated from livers of human fetuses. Cytochrome P450 cDNAs, namely lambda hPA6, lamda hP2-1, and lambda hPD4 which were highly homologous to cDNA clones, pHY13, Hp1-1, and phP450j, respectively, were also isolated from the cDNA library of human adult livers. Using these cDNA clones as probes together with Lambda HFL10, Northern blot analysis was conducted to determine whether all of these cytochromes were expressed in human fetal livers. The results clearly showed that only P450 HFL10 mRNA was detected in human fetal livers. This result supports the allegation that there is a much more limited number of forms of cytochrome P450 in human fetal livers than in adult livers. PMID:2786707

Komori, M; Nishio, K; Fujitani, T; Ohi, H; Kitada, M; Mima, S; Itahashi, K; Kamataki, T

1989-07-01

423

Experimental study of limit lean methane/air flame in a standard flammability tube using particle image velocimetry method  

SciTech Connect

Lean limit methane/air flame propagating upward in a standard 50 mm diameter and 1.8 m length tube was studied experimentally using particle image velocimetry method. Local stretch rate along the flame front was determined by measured gas velocity distributions. It was found that local stretch rate is maximum at the flame leading point, which is in agreement with earlier theoretical results. Similar to earlier observations, extinction of upward propagating limit flame was observed to start from the flame top. It is stated that the observed behavior of the extinction of the lean limit methane/air flame can not be explained in terms of the coupled effect of flame stretch and preferential diffusion. To qualitatively explain the observed extinction behavior, it is suggested that the positive strain-induced flame stretch increases local radiation heat losses from the flame front. An experimental methodology for PIV measurements in a round tube is described. (author)

Shoshin, Yuriy; Gorecki, Grzegorz; Jarosinski, Jozef; Fodemski, Tadeusz [Department of Heat Technology and Refrigeration, Technical University of Lodz, Lodz 90-924 (Poland)

2010-05-15

424

The Intracellular Sensor NOD2 Induces MicroRNA-29 Expression in Human Dendritic Cells to Limit IL-23 Release.  

PubMed

NOD2 is an intracellular sensor that contributes to immune defense and inflammation. Here we investigated whether NOD2 mediates its effects through control of microRNAs (miRNAs). miR-29 expression was upregulated in human dendritic cells (DCs) in response to NOD2 signals, and miR-29 regulated the expression of multiple immune mediators. In particular, miR-29 downregulated interleukin-23 (IL-23) by targeting IL-12p40 directly and IL-23p19 indirectly, likely via reduction of ATF2. DSS-induced colitis was worse in miR-29-deficient mice and was associated with elevated IL-23 and T helper 17 signature cytokines in the intestinal mucosa. Crohn's disease (CD) patient DCs expressing NOD2 polymorphisms failed to induce miR-29 upon pattern recognition receptor stimulation and showed enhanced release of IL-12p40 on exposure to adherent invasive E. coli. Therefore, we suggest that loss of miR-29-mediated immunoregulation in CD DCs might contribute to elevated IL-23 in this disease. PMID:24054330

Brain, Oliver; Owens, Benjamin M J; Pichulik, Tica; Allan, Philip; Khatamzas, Elham; Leslie, Alasdair; Steevels, Tessa; Sharma, Sameer; Mayer, Alice; Catuneanu, Ana Maria; Morton, Victoria; Sun, Mei-Yi; Jewell, Derek; Coccia, Margherita; Harrison, Oliver; Maloy, Kevin; Schönefeldt, Susann; Bornschein, Simon; Liston, Adrian; Simmons, Alison

2013-09-19

425

Physiologically based pharmacokinetics of radioiodinated human beta-endorphin in rats. An application of the capillary membrane-limited model  

SciTech Connect

In order to simulate the distribution and elimination of radioiodinated human beta-endorphin (/sup 125/I-beta-EP) after iv bolus injection in rats, we proposed a physiologically based pharmacokinetic model incorporating diffusional transport of /sup 125/I-beta-EP across the capillary membrane. This model assumes that the distribution of /sup 125/I-beta-EP is restricted only within the blood and the tissue interstitial fluid, and that a diffusional barrier across the capillary membrane exists in each tissue except the liver. The tissue-to-blood partition coefficients were estimated from the ratios of the concentration in tissues to that in arterial plasma at the terminal (pseudoequilibrium) phase. The total body plasma clearance (9.0 ml/min/kg) was appropriately assigned to the liver and kidney. The transcapillary diffusion clearances of /sup 125/I-beta-EP were also estimated and shown to correlate linearly with that of inulin in several tissues. Numerically solving the mass-balance differential equations as to plasma and each tissue simultaneously, simulated concentration curves of /sup 125/I-beta-EP corresponded well with the observed data. It was suggested by the simulation that the initial rapid disappearance of /sup 125/I-beta-EP from plasma after iv injection could be attributed in part to the transcapillary diffusion of the peptide.

Sato, H.; Sugiyama, Y.; Sawada, Y.; Iga, T.; Hanano, M.

1987-07-01

426

Survival, Functional Limitations, and Self-rated Health in the NHANES I Epidemiologic Follow-up Study, 1992  

Microsoft Academic Search

This study examined relative hazards for mortality and functional limitations according to poor self-ratings of health using prospective data from the NHANES I Epidemiologic Follow-up Study, a representative sample of US adults aged 25-74 years that has been followed since the First National Health and Nutrition Examination Survey (NHANES I) was conducted in 1971-1975. Follow-up data were taken from death

Ellen L. Idler; Louise B. Russell; Diane Davis

427

Intermolecular electron transfer rate in diffusion limited region: Picosecond fluorescence studies  

NASA Astrophysics Data System (ADS)

The temporal profiles of the quenched fluorescence decay of the free base meso-tetraphenyl porphyrin (H 2TPP) and its Zn derivative (ZnTPP) with quenchers such as quinones and m-dinitrobenzene have been analysed by methods developed for short time regimes which are known to be diffusion influenced [N. Periasamy et al., J. Chem. Phys.88, 1638 (1988); 89, 4799 (1988); Chem. Phys. Lett.160, 457 (1989); N. Periasamy, Biophys. J.. 54, 961 (1988); R. Das and N. Periasamy, Chem. Phys. 136, 361 (1989); G.C. Joshi et al., J. Phys. Chem.94, 2908 (1990)]. These quenchers are known to participate in an electron transfer reaction leading to a charge separation. The intrinsic rate constant ( ka) derived from the analysis is examined as a function of the change in free energy in the electron transfer reaction. Such a comparison indicates that ka can be related to the electron transfer rate, ket. The electron transfer rates measured in acetonitrile (solvent reorganization energy, ? s = 1.35) and toluene (? s = 0.1) do not indicate the existence of an inverted region as predicted by Marcus. The trend agrees with the findings of Rehm and Weller [ Isr. J. Chem.8, 259 (1970)], except that the rate constants are at least one order of magnitude larger than the diffusion limited values.

Venkataraman, B.; Periasamy, N.; Modi, S.; Dutt, G. Bhaskar; Doraiswamy, S.

1992-12-01

428

Studies of spectral modification and limitations of the modified paraxial equation in laser wakefield simulations  

NASA Astrophysics Data System (ADS)

Laser pulses propagating through plasma undergo spectral broadening through local energy exchange with driven plasma waves. For propagation distances on the order of the energy depletion length, spectral shifts can be comparable to the laser central frequency and wavenumber, a result of approximate action conservation. Here, we examine the local spectral shift, energy depletion, and action conservation of nonlinear laser pulses using the modified paraxial simulation code WAKE. Breakdown of the modified paraxial equation (MPE), which is based on the assumption of slow temporal variation of the pulse envelope, is monitored via consideration of the wave action. Although action is theoretically conserved for the continuous MPE, we observe that for large red shifts, action decays for the discrete implementation. Numerical analysis of the propagation algorithm verified the observed behavior. Increasing resolution improves action conservation up to a time, which is identified to be the validity limit for the MPE. Increased resolution also leads to increased simulation times and eliminates the strength of the MPE solver-efficiency.

Zhu, W.; Palastro, J. P.; Antonsen, T. M.

2012-03-01

429

Computational Study of Near-Limit Propagation of Detonation in Hydrogen-Air Mixtures  

NASA Astrophysics Data System (ADS)

A computational investigation of the near-limit propagation of detonation in lean and rich hydrogen-air mixtures is presented. The calculations were carried out over an equivalence ratio range of 0.4 to 5.0, pressures ranging from 0.2 bar to 1.0 bar and ambient initial temperature. The computations involved solution of the one-dimensional Euler equations with detailed finite-rate chemistry. The numerical method is based on a second-order spatially accurate total-variation-diminishing (TVD) scheme, and a point implicit, first-order-accurate, time marching algorithm. The hydrogen-air combustion was modeled with a 9-species, 19-step reaction mechanism. A multi-level, dynamically adaptive grid was utilized in order to resolve the structure of the detonation. The results of the computations indicate that when hydrogen concentrations are reduced below certain levels, the detonation wave switches from a high-frequency, low amplitude oscillation mode to a low frequency mode exhibiting large fluctuations in the detonation wave speed; that is, a 'galloping' propagation mode is established.

Yungster, S.; Radhakrishnan, K.

2002-10-01

430

Estimation by limiting dilution analysis of human IL 2-secreting T cells: detection of IL 2 produced by single lymphokine-secreting T cells  

SciTech Connect

We present here a culture method for the estimation, in human blood, of the number of lymphocytes that can respond to mitogen by producing interleukin 2 (IL 2). T cells are cultured at limiting dilutions with PHA or Con A in the presence of Epstein Barr virus-transformed human lymphoblastoid cells (EB-LCL), and supernatants are tested 3 days later for IL 2 content by a cell proliferation assay. The distribution of negative wells follows the expected Poisson single-hit relationship, suggesting that the assay is sensitive to single cells of a single limiting cell type. On average, 16.3% of peripheral blood mononuclear cells can produce IL 2 in such clonal cultures (mean of 12 determinations; SD = 5.6%). Surprisingly, irradiation (up to 2000 rad) of the titrated responder cell population diminishes the estimated frequencies by less than 50%. The ability to detect IL 2 levels in cultures containing only a single, nonproliferating T lymphocyte allows us to estimate the amount of IL 2 generated by an individual effector cell during a 3-day culture interval after mitogen stimulation. The average responding, irradiated T cell generates 0.92 pg of IL 2 (median) within 3 days. The method presented provides a straightforward way to provide independent estimates of responding cell number and of lymphokine production per cell in a variety of clinical situations.

Vie, H.; Miller, R.A.

1986-05-01

431

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

432

Study of brightness and current limitations in intense charged particle beams  

Microsoft Academic Search

Over the past several years of ONR support for our research program we have mainly studied the various schemes for intense, high-brightness H(-) beam transport and focusing in the context of its application in space defense. Detailed theoretical studies revealed that the conventional gas focusing system is not suitable as a low-energy beam transport (LEBT) system and also that there

M. Reiser; S. Guharay

1993-01-01

433

Pioneering space based detector for study of cosmic rays beyond GZK Limit  

NASA Astrophysics Data System (ADS)

Space-based detectors for study of extreme energy cosmic rays (EECR) are being prepared as promising new direction of EECR study. Pioneering space device - tracking ultraviolet set up (TUS) is at the last stage of its construction and testing. TUS detector description is presented.

Khrenov, B. A.; Panasyuk, M. I.; Garipov, G. K.; Kalmykov, N. N.; Klimov, P. A.; Morozenko, V. S.; Sharakin, S. A.; Shirokov, A. V.; Yashin, I. V.; Biktemerova, S. V.; Grinyuk, A. A.; Naumov, D. V.; Tkachev, L. G.; Tkachenko, A. V.; Saprykin, O. A.; Botvinko, A. A.; Park, I.; Lee, J.; Na, G.; Martinez, O.; Salazar, H.; Ponce, E.

2013-06-01

434

The Institute for the Interdisciplinary Study of Human & Machine Cognition  

NSDL National Science Digital Library

The Institute for the Interdisciplinary Study of Human & Machine Cognition (IHMC) is an interdisciplinary research unit of the University of West Florida. Researchers and staff at the IHMC investigate "a broad range of topics related to understanding cognition in both humans and machines with a particular emphasis on building computational tools to leverage and amplify human cognitive and perceptual capacities." Their work advances the study of human-centered computing, which takes a Âsystems view to link human thought and action and technological systems. They are primarily interested in the analysis, design, and evaluation of computational aids or "cognitive prostheses." The website provides an overview of each of their current research areas, which include: knowledge modeling and sharing, adjustable autonomy, advanced interfaces and displays, communication and collaboration, computer-mediated learning systems, intelligent data understanding, software agents, expertise studies, work practice simulation, knowledge representation, and other related areas. They also provide Cmap Tools, a knowledge modeling software kit, which is free to download and "empowers users to construct, navigate, share, and criticize knowledge models represented as Concept Models." This site is also reviewed in the June 3, 2005.

435

Studies of human milk relevant to milk banking.  

PubMed

Issues regarding the efficacy of feeding human milk to premature infants include the development of optimal protocols for collecting, storing, and processing human milk. Studies of the nutritional and immunologic composition of milk produced by women who delivered term or premature infants and who weaned their infants gradually from human milk have been studied to identify optimal donors. The effects of specific collection, storage, and processing conditions on the composition of mature human milk also have been evaluated. Collection, storage, and processing conditions have distinct effects on specific functional components. The caloric content of milk, the content of nutrients carried in the lipid portion of milk, and selected enzymatic activities depend on the completeness with which the breast is emptied. Storing milk in polyethylene, polypropylene, and pyrex containers influences key immunologic components in human milk as do storage temperatures. None of the nutrient compositions of milks studied matched current estimates of the nutritional needs of premature infants. Importantly, both the concentrations and the pattern of change in nutrient and immunologic contents are distinct in milks of women delivering infants at term or prematurely. Further changes are seen during the process of gradual weaning. PMID:6470353

Garza, C; Nichols, B L

1984-01-01

436

Coronary collaterals provide a constant scaffold effect on the left ventricle and limit ischemic left ventricular dysfunction in humans  

PubMed Central

Coronary collaterals preserve left ventricular (LV) function during coronary occlusion by reducing myocardial ischemia and may directly influence LV compliance. We aimed to re-evaluate the relationship between coronary collaterals, measured quantitatively with a pressure wire, and simultaneously recorded LV contractility from conductance catheter data during percutaneous coronary intervention (PCI) in humans. Twenty-five patients with normal LV function awaiting PCI were recruited. Pressure-derived collateral flow index (CFIp): CFIp = (Pw ? Pv)/(Pa ? Pv) was calculated from pressure distal to coronary balloon occlusion (Pw), central venous pressure (Pv), and aortic pressure (Pa). CFIp was compared with the changes in simultaneously recorded LV end-diastolic pressure (?LVEDP), end-diastolic volume, maximum rate of rise in pressure (?LVdP/dtmax; systolic function), and time constant of isovolumic relaxation (?LV ?; diastolic function), measured by a LV cavity conductance catheter. Measurements were recorded at baseline and following a 1-min coronary occlusion and were duplicated after a 30-min recovery period. There was significant LV diastolic dysfunction following coronary occlusion (?LVEDP: +24.5%, P < 0.0001; and ?LV ?: +20.0%, P < 0.0001), which inversely correlated with CFIp (?LVEDP vs. CFIp: r = ?0.54, P < 0.0001; ?LV ? vs. CFIp: r = ?0.46, P = 0.0009). Subjects with fewer collaterals had lower LVEDP at baseline (r = 0.33, P = 0.02). CFIp was inversely related to the coronary stenosis pressure gradient at rest (r = ?0.31, P = 0.03). Collaterals exert a direct hemodynamic effect on the ventricle and attenuate ischemic LV diastolic dysfunction during coronary occlusion. Vessels with lesions of greater hemodynamic significance have better collateral supply.

Hoole, Stephen P.; White, Paul A.; Read, Philip A.; Heck, Patrick M.; West, Nick E.; O'Sullivan, Michael

2012-01-01

437

Studies of the limited degradation of mucus glycoproteins. The mechanism of the peroxide reaction.  

PubMed Central

The reaction between ovarian-cyst glycoproteins and H2O2 was investigated in the presence of a number of inhibitors and catalysts. Azide and 2H2O were separately found to have little effect, implying that singlet oxygen was not involved. Superoxide dismutase was destroyed by H2O2, but mannitol had no effect: thus generalized attack by OH., whether originating from HO2.- or more directly, is not indicated. The glycoproteins contained trace quantities of Cu and Fe, amounting to about 2 atoms of metal per glycoprotein molecule. Treatment of the glycoproteins with the strong chelator DETAPAC (diethylenetriaminepenta-acetic acid) or Chelex resin eliminated the reaction with H2O2; activity could be restored by addition of Cu2+ or Fe2+ in millimolar quantities. It was concluded that metal-ion catalysis is an essential step in the attack of H2O2 on glycoproteins. Spectroscopic and other evidence showed that Cu2+ (and probably Fe2+) complexes strongly with poly-L-histidine, and implies that the Cu2+ or Fe2+ in the glycoproteins is complexed with some of the histidine residues in the glycosylated backbone. Neither polyhistidine nor polyproline reacted with H2O2 in the absence of metal ions, but small quantities of Cu2+ or Fe3+ caused degradation. This was rapid with polyhistidine, which was converted largely into aspartic acid, but slower with polyproline, where limited conversion into glutamic acid occurs. These findings confirm the original hypothesis that peroxide attack on glycoproteins occurs largely at the histidine residues, with simultaneous peptidolysis. The mechanism most probably involves the liberation of OH. by an oxidation-reduction cycle involving, e.g. Cu+/Cu2+: specificity of attack at histidine is due to the location of the metal at these residues only.

Cooper, B; Creeth, J M; Donald, A S

1985-01-01

438

The Study of WGamma production at D0: Anomalous Coupling Limits and the Radiation Amplitude Zero  

SciTech Connect

W{gamma} production is analyzed in the electron and muon decay channels with approximately 1 fb{sup -1} of data from p{bar p} collisions that were produced at a center-of-mass energy of {radical}s = 1.96 TeV and that were collected by the D0 detector at the Fermilab Tevatron collider. The inclusive p{bar p} {yields} {ell}{nu}{gamma} cross section is measured in both channels and is found to be consistent with the Standard Model expectation of 2.08 {+-} 0.05{sub PDF} pb for events with a photon E{sub T} > 11 GeV, {Delta}R{sub {ell}{sub {gamma}}} > 0.7, and {ell}{nu}{gamma} transverse mass greater than 90 GeV . The observed cross section is measured to be 2.05 {+-} 0.18{sub stat} {+-} 0.10{sub sys} {+-} 0.13{sub lumi} pb and a.72 {+-} 0.19{sub stat} {+-} 0.15{sub sys} {+-} 0.10{sub lumi} pb for the electron and muon channels respectively. The photon E{sub T} spectrum is examined for indications of anomalous WW{gamma} couplings. No evidence is found, and the following one-dimensional limits are set at a 95% confidence level: -0.18 < {lambda} < 0.18 and 0.16 < {kappa} < 1.84. The observed charge-signed photon-lepton rapidity difference is consistent with the Standard Model prediction and is indicative of the theoretically expected radiation amplitude zero. The distribution exhibits a bimodal structure which is expected from the destructive interference, with the unimodal hypothesis being ruled out at the 94% confidence level.

Pawloski, Gregory J.; /Rice U.

2007-06-01