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1

The application of genetics approaches to the study of exceptional longevity in humans: potential and limitations  

PubMed Central

The average life-span of the population of industrialized countries has improved enormously over the last decades. Despite evidence pointing to the role of food intake in modulating life-span, exceptional longevity is still considered primarily an inheritable trait, as pointed out by the description of families with centenarian clusters and by the elevated relative probability of siblings of centenarians to become centenarians themselves. However, rather than being two separate concepts, the genetic origin of exceptional longevity and the more recently observed environment-driven increase in the average age of the population could possibly be explained by the same genetic variants and environmentally modulated mechanisms (caloric restriction, specific nutrients). In support of this hypothesis, polymorphisms selected for in the centenarian population as a consequence of demographic pressure have been found to modulate cellular signals controlled also by caloric restriction. Here, we give an overview of the recent findings in the field of the genetics of human exceptional longevity, of how some of the identified polymorphisms modulate signals also influenced by food intake and caloric restriction, of what in our view have been the limitations of the approaches used over the past years to study genetics (sib-pair-, candidate gene association-, and genome-wide association-studies), and briefly of the limitations and the potential of the new, high-throughput, next-generation sequencing techniques applied to exceptional longevity. PMID:22524405

2012-01-01

2

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

3

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.

4

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

5

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

6

Phosphorus: a limiting nutrient for humanity?  

PubMed

Phosphorus is a chemical element that is essential to life because of its role in numerous key molecules, including DNA and RNA; indeed, organisms require large amounts of P to grow rapidly. However, the supply of P from the environment is often limiting to production, including to crops. Thus, large amounts of P are mined annually to produce fertilizer that is applied in support of the 'Green Revolution.' However, much of this fertilizer eventually ends up in rivers, lakes and oceans where it causes costly eutrophication. Furthermore, given increasing human population, expanding meat consumption, and proliferating bioenergy pressures, concerns have recently been raised about the long-term geological, economic, and geopolitical viability of mined P for fertilizer production. Together, these issues highlight the non-sustainable nature of current human P use. To achieve P sustainability, farms need to become more efficient in how they use P while society as a whole must develop technologies and practices to recycle P from the food chain. Such large-scale changes will probably require a radical restructuring of the entire food system, highlighting the need for prompt but sustained action. PMID:22465489

Elser, James J

2012-12-01

7

Teleoperator Human Factors Study  

NASA Technical Reports Server (NTRS)

An investigation of the spectrum of space teleoperation activities likely in the 1985 to 1995 decade focused on the resolution of critical human engineering issues and characterization of the technology effect on performance of remote human operators. The study began with the identification and documentation of a set of representative reference teleoperator tasks. For each task, technology, development, and design options, issues, and alternatives that bear on human operator performance were defined and categorized. A literature survey identified existing studies of man/machine issues. For each teleoperations category, an assessment was made of the state of knowledge on a scale from adequate to void. The tests, experiments, and analyses necessary to provide the missing elements of knowledge were then defined. A limited set of tests were actually performed, including operator selection, baseline task definition, control mode study, lighting study, camera study, and preliminary time delay study.

1986-01-01

8

The limits of agency in walking humans.  

PubMed

An important principle of human ethics is that individuals are not responsible for actions performed when unconscious. Recent research found that the generation of an action and the building of a conscious experience of that action (agency) are distinct processes and crucial mechanisms for self-consciousness. Yet, previous agency studies have focussed on actions of a finger or hand. Here, we investigate how agents consciously monitor actions of the entire body in space during locomotion. This was motivated by previous work revealing that (1) a fundamental aspect of self-consciousness concerns a single and coherent representation of the entire spatially situated body and (2) clinical instances of human behaviour without consciousness occur in rare neurological conditions such as sleepwalking or epileptic nocturnal wandering. Merging techniques from virtual reality, full-body tracking, and cognitive science of conscious action monitoring, we report experimental data about consciousness during locomotion in healthy participants. We find that agents consciously monitor the location of their entire body and its locomotion only with low precision and report that while precision remains low it can be systematically modulated in several experimental conditions. This shows that conscious action monitoring in locomoting agents can be studied in a fine-grained manner. We argue that the study of the mechanisms of agency for a person's full body may help to refine our scientific criteria of self-hood and discuss sleepwalking and related conditions as alterations in neural systems encoding motor awareness in walking humans. PMID:20144893

Kannape, O A; Schwabe, L; Tadi, T; Blanke, O

2010-05-01

9

Limited proteolysis of human histone deacetylase 1  

PubMed Central

Background Histone deacetylase (HDAC) proteins are associated with cell proliferation, differentiation, apoptosis, and cancer. Specifically, HDAC1 is linked with cell growth, a hallmark of cancer formation. HDAC1 is a phosphoprotein and phosphorylation at S421 and S423 promotes HDAC1 enzymatic activity and protein association. While single and double point mutants of HDAC1 at S421 and S423 appear functionally similar, the evidence suggests that HDAC1 is phosphorylated simultaneously at both S421 and S423 in vivo. Additional experiments are necessary to probe the role of double phosphorylation of HDAC1 at S421 and S423. Results To characterize HDAC1 phosphorylation at S421 and S423, limited proteolysis of HDAC1 was performed for the first time. HDAC1 degraded without production of discrete fragments. By performing concentration-dependent proteolysis, HDAC1 double point mutants with disrupted phosphorylation at S421 and S423 displayed different trypsin sensitivities compared to wild type HDAC1. Unexpectedly, HDAC1 single point mutants with disrupted phosphorylation at either S421 or S423 demonstrated protease sensitivity similar to the wild type HDAC1. Conclusion Concentration-dependent proteolysis experiments provide evidence that phosphorylation of S421 and S423 individually contribute to HDAC1 function. In addition, the limited proteolysis experiments support a model where associated proteins promote HDAC1 enzymatic activity, reinforcing the importance of protein interactions in HDAC1 structure and function. Finally, because HDAC1 does not display distinct regions of protease sensitivity, the proteolysis studies suggest that HDAC1 comprises inter-related structural regions. PMID:17022812

Kamath, Nayana; Karwowska-Desaulniers, Paulina; Pflum, Mary Kay H

2006-01-01

10

Using Symbiotic Relationships with Humans to Help Robots Overcome Limitations  

Microsoft Academic Search

We are interested in task-driven robots in our environments that can communicate with humans. While today's robots often communicate with humans to overcome their limited perception and execution, the relationship between humans and robots is often one-sided in which the human is pro- viding all the help to the robot without their own benets. Instead, we propose a symbiotic relationship

Stephanie Rosenthal; Manuela Veloso

11

Limiting Reactants: Industrial Case Study  

NSDL National Science Digital Library

An exercise in which students apply limiting reactants, mass ratios and percent yields to suggest an optimum industrial process. Cost figures are provided but students are told to come up with, and defend, their own criteria for their recommendation.

Blackburn, Dave

12

The limits of human athletic performance.  

PubMed

For each individual, there is a limit to the capacity to perform exercise. The limitation, however, depends on the nature of the task and is also influenced by a number of other factors. Muscle strength is determined largely by muscle mass, specifically muscle cross-sectional area, but is also influenced by neural drive and biomechanical factors. Endurance performance depends on both cardiovascular capacity and the metabolic characteristics of the skeletal muscles. These factors are determined in part by genetic endowment: the elite sprinter has a high proportion of Type 2 muscle fibres while the leg muscles of the successful marathon runner are composes mainly of Type 1 fibres. Whatever the genetic potential, expression of this depends on the intensity, duration and frequency of the applied training stimulus, diet and other factors. The limitation may also depend on environmental factors, such as altitude and temperature. PMID:17037090

Maughan, R J

2005-01-01

13

Human factor and computational intelligence limitations in resilient control systems  

E-print Network

Human factor and computational intelligence limitations in resilient control systems Bogdan M of replacing humans with computers using artificial intelligence, expert systems, or methods of computational computer aided tools humans were not able to design chips larger than 100 transistors. Also, with usage

Wilamowski, Bogdan Maciej

14

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

2013-01-01

15

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. PMID:24113276

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

2013-01-01

16

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

17

Using Symbiotic Relationships with Humans to Help Robots Overcome Limitations  

E-print Network

Using Symbiotic Relationships with Humans to Help Robots Overcome Limitations Stephanie Rosenthal without their own benefits. Instead, we propose a symbiotic relationship in which the robot performs tasks for humans and only ask for help to complete the task successfully. The symbiotic relationship is a more

Veloso, Manuela M.

18

Hierarchical implicit surface joint limits for human body tracking  

Microsoft Academic Search

To increase the reliability of existing human motion tracking algorithms, we propose a method for imposing limits on the underlying hierarchical joint structures in a way that is true to life. Unlike most existing approaches, we explicitly represent dependencies between the various degrees of freedom and derive these limits from actual experimental data. To this end, we use quaternions to

L. Herda; Raquel Urtasun; P. Fua

2005-01-01

19

Studies on the dynamics of limited filaments  

E-print Network

A study on the dynamics of filaments in the presence of a diagnostic, conductive limiter is presented. Plasma filaments are coherent structures present in many fusion devices and transport a significant amount of particles ...

Bonde, Jeffrey David

2010-01-01

20

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.

21

Artificial Closed Ecosystems Stability and Human Control Limitations  

NASA Astrophysics Data System (ADS)

The stability of the complex ecological system of the Earth accommodates statistical variation through the existence of extensive planetary buffers in atmosphere, water, soil, time, and energy sources. Variation in the Earth biosphere caused by either natural mechanisms or human activity is readily absorbed by these systemic, planetary buffers. Artificial Closed Ecological Systems (CES) for long-term life support in space are marginally stable to unstable due to insufficient buffer capacities stemming from significantly smaller system size and mass in space adaptations. Manual control can improve stability of such systems if CES system-specific control algorithms are applied. This paper introduces a conceptual model for CES stability and suggests system characteristics to maintain this stability for extended durations. Numerical estimates for CES of various scales and configurations, e.g., Biosphere of the Earth, Biosphere 2 (USA), BIOS 3 (Russia), Closed Ecological Experimental Facility (CEEF, Japan), etc., show that stability limits exist and differ for each specific system. These limits are determined primarily by: 1. The slowest circulating (so called limiting) material cycle in the system; 2. The buffer capacities for this cycle (cycle reservoirs); 3. The natural structure and intensity (rate) of the material turnover. Humans as an element of the system can exert control in a variety of manners. Human control can improve stability significantly but the controller must have a comprehensive understanding of closed material cycles structural (network related) and dynamical (turnover time related) characteristics. This understanding requires better models of the Earth biosphere mechanisms, as well as greater extensive experimentation with these models.

Rygalov, Vadim; Casler, James G.; Holubnyak, Yevhen

22

Human endothelial dihydrofolate reductase low activity limits vascular tetrahydrobiopterin recycling.  

PubMed

Tetrahydrobiopterin (BH?) is required for NO synthesis and inhibition of superoxide release from endothelial NO synthase. Clinical trials using BH? to treat endothelial dysfunction have produced mixed results. Poor outcomes may be explained by the rapid systemic and cellular oxidation of BH?. One of the oxidation products of BH?, 7,8-dihydrobiopterin (7,8-BH?), is recycled back to BH? by dihydrofolate reductase (DHFR). This enzyme is ubiquitously distributed and shows a wide range of activity depending on species-specific factors and cell type. Information about the kinetics and efficiency of BH4 recycling in human endothelial cells receiving BH? treatment is lacking. To characterize this reaction, we applied a novel multielectrode coulometric HPLC method that enabled the direct quantification of 7,8-BH? and BH?, which is not possible with fluorescence-based methodologies. We found that basal untreated BH? and 7,8-BH? concentrations in human endothelial cells (ECs) are lower than in bovine and murine endothelioma cells. Treatment of human ECs with BH? transiently increased intracellular BH? while accumulating the more stable 7,8-BH?. This was different from bovine or murine ECs, which resulted in preferential BH? increase. Using BH? diastereomers, 6S-BH? and 6R-BH?, the narrow contribution of enzymatic DHFR recycling to total intracellular BH? was demonstrated. Reduction of 7,8-BH? to BH? occurs at very slow rates in cells and needs supraphysiological levels of 7,8-BH?, indicating this reaction is kinetically limited. Activity assays verified that human DHFR has very low affinity for 7,8-BH? (DHF7,8-BH?) and folic acid inhibits 7,8-BH? recycling. We conclude that low activity of endothelial DHFR is an important factor limiting the benefits of BH4 therapies, which may be further aggravated by folate supplements. PMID:23707606

Whitsett, Jennifer; Rangel Filho, Artur; Sethumadhavan, Savitha; Celinska, Joanna; Widlansky, Michael; Vasquez-Vivar, Jeannette

2013-10-01

23

Humanized Mouse Models to Study Human Diseases  

PubMed Central

Purpose of review Update on humanized mouse models and their use in biomedical research. Recent findings The recent description of immunodeficient mice bearing a mutated IL-2 receptor gamma chain (IL2ry) facilitated greatly the engraftment and function of human hematolymphoid cells and other cells and tissues. These mice permit the development of human immune systems, including functional T and B cells, following engraftment of hematopoietic stem cells (HSC). The engrafted functional human immune systems are capable of T and B cell-dependent immune responses, antibody production, anti-viral responses, and allograft rejection. Immunodeficient IL2rynull mice also support heightened engraftment of primary human cancers and malignant progenitor cells, permitting in vivo investigation of pathogenesis and function. In addition, human-specific infectious agents for which animal models were previously unavailable can now be studied in vivo using these new generation humanized mice. Summary Immunodeficient mice bearing an IL2rynull mutated gene can be engrafted with functional human cells and tissues, including human immune systems, following engraftment with human hematolymphoid cells. These mice are now used as in vivo models to study human hematopoiesis, immunity, regeneration, stem cell function, cancer, and human-specific infectious agents without putting patients at risk. PMID:20150806

Brehm, Michael A.; Shultz, Leonard D.; Greiner, Dale L.

2010-01-01

24

The limits of human stereopsis in space and time.  

PubMed

To encode binocular disparity, the visual system determines the image patches in one eye that yield the highest correlation with patches in the other eye. The computation of interocular correlation occurs after spatiotemporal filtering of monocular signals, which leads to restrictions on disparity variations that can support depth perception. We quantified those restrictions by measuring humans' ability to see disparity variation at a wide range of spatial and temporal frequencies. Lower-disparity thresholds cut off at very low spatiotemporal frequencies, which is consistent with the behavior of V1 neurons. Those thresholds are space-time separable, suggesting that the underlying neural mechanisms are separable. We also found that upper-disparity limits were characterized by a spatiotemporal, disparity-gradient limit; to be visible, disparity variation cannot exceed a fixed amount for a given interval in space-time. Our results illustrate that the disparity variations that humans can see are very restricted compared with the corresponding luminance variations. The results also provide insight into the neural mechanisms underlying depth from disparity, such as why stimuli with long interocular delays can still yield clear depth percepts. PMID:24453329

Kane, David; Guan, Phillip; Banks, Martin S

2014-01-22

25

Human Paraoxonase 1 as a Pharmacologic Agent: Limitations and Perspectives  

PubMed Central

Human PON1 (h-PON1) is a multifaceted enzyme and can hydrolyze (and inactivate) a wide range of substrates. The enzyme shows anti-inflammatory, antioxidative, antiatherogenic, ant-diabetic, antimicrobial, and organophosphate (OP)-detoxifying properties. However, there are certain limitations regarding large-scale production and use of h-PON1 as a therapeutic candidate. These include difficulties in producing recombinant h-PON1 (rh-PON1) using microbial expression system, low hydrolytic activity of wild-type h-PON1 towards certain substrates, and low storage stability of the purified enzyme. This review summarizes the work done in our laboratory to address these limitations. Our results show that (a) optimized polynucleotide sequence encoding rh-PON1 can express the protein in an active form in E. coli and can be used to generate variant of the enzyme having enhanced hydrolytic activity, (b) in vitro refolding of rh-PON1 enzyme can dramatically increase the yield of an active enzyme, (c) common excipients can be used to stabilize purified rh-PON1 enzyme when stored under different storage conditions, and (d) variants of rh-PON1 enzyme impart significant protection against OP-poisoning in human blood (ex vivo) and mouse (in vivo) model of OP-poisoning. The rh-PON1 variants and their process of production discussed here will help to develop h-PON1 as a therapeutic candidate. PMID:25386619

Bajaj, Priyanka; Tripathy, Rajan K.; Aggarwal, Geetika; Pande, Abhay H.

2014-01-01

26

Limitations in simulator time-based human reliability analysis methods  

SciTech Connect

Developments in human reliability analysis (HRA) methods have evolved slowly. Current methods are little changed from those of almost a decade ago, particularly in the use of time-reliability relationships. While these methods were suitable as an interim step, the time (and the need) has come to specify the next evolution of HRA methods. As with any performance-oriented data source, power plant simulator data have no direct connection to HRA models. Errors reported in data are normal deficiencies observed in human performance; failures are events modeled in probabilistic risk assessments (PRAs). Not all errors cause failures; not all failures are caused by errors. Second, the times at which actions are taken provide no measure of the likelihood of failures to act correctly within an accident scenario. Inferences can be made about human reliability, but they must be made with great care. Specific limitations are discussed. Simulator performance data are useful in providing qualitative evidence of the variety of error types and their potential influences on operating systems. More work is required to combine recent developments in the psychology of error with the qualitative data collected at stimulators. Until data become openly available, however, such an advance will not be practical.

Wreathall, J.

1989-01-01

27

Limited communication capacity unveils strategies for human interaction  

PubMed Central

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

28

Endothelial human dihydrofolate reductase low activity limits vascular tetrahydrobiopterin recycling  

PubMed Central

Tetrahydrobiopterin (BH4) is required for NO synthesis and inhibition of superoxide release from eNOS. Clinical trials using BH4 to treat endothelial dysfunction have produced mixed results. Poor outcomes may be explained by the rapid systemic and cellular oxidation of BH4. One of the oxidation products of BH4, 7,8-dihydrobiopterin (7,8-BH2), is recycled back to BH4 by dihydrofolate reductase (DHFR). This enzyme is ubiquitously distributed and shows a wide range of activity depending on species-specific factors and cell type. Information about the kinetics and efficiency of BH4 recycling in human endothelial cells receiving BH4 treatment is lacking. To characterize this reaction, we applied a novel multi-electrode coulometric HPLC method that enabled the direct quantification of 7,8-BH2 and BH4 which is not possible with fluorescent-based methodologies. We found that basal untreated BH4 and 7,8-BH2 concentrations in human ECs is lower than bovine and murine endothelioma cells. Treatment of human ECs with BH4 transiently increased intracellular BH4 while accumulating the more stable 7,8-BH2. This was different from bovine or murine ECs that resulted in preferential BH4 increase. Using BH4 diastereomers, 6S-BH4 and 6R-BH4, the narrow contribution of enzymatic DHFR recycling to total intracellular BH4 was demonstrated. Reduction of 7,8-BH2 to BH4 occurs at very slow rates in cells and needs supra-physiological levels of 7,8-BH2, indicating this reaction is kinetically limited. Activity assays verified that hDHFR has very low affinity for 7,8-BH2 (DHF7,8-BH2) and folic acid inhibits 7,8-BH2 recycling. We conclude that low activity of endothelial DHFR is an important factor limiting the benefits of BH4 therapies which may be further aggravated by folate supplements. PMID:23707606

Whitsett, Jennifer; Filho, Artur Rangel; Sethumadhavan, Savitha; Celinska, Joanna; Widlansky, Michael; Vasquez-Vivar, Jeannette

2013-01-01

29

Limited study of mechanical intelligence as media.  

E-print Network

??The project investigates mathematics, informatics, statistical analysis and their histories, the history of human engagement with machines, and illustrates some uses of artificial intelligence and… (more)

Middleton, S

2007-01-01

30

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

31

HUMAN DEVELOPMENT Program of Study  

E-print Network

HUMAN DEVELOPMENT Program of Study Financial Aid Students Applying Correspondence The graduate program in Human Development is designed to provide advanced training, with special emphasis on child development and family relations. This program is designed for those interested in working in the human

Thomas, Andrew

32

[Research with human embryo stem cells. Foundations and judicial limits].  

PubMed

Research with human embryos, and particularly, the use for scientific purposes of human embryonic stem cells has given raise to different sort of problems at the international level. One of the most strict regulation in this field, is this lecture Professors Albin Eser and Hans-Georg Koch analyse the german legal framework in relation with the use of embryos and human embryonic stem cells for scientific purposes. PMID:15544142

Eser, Albin; Koch, Hans-Georg

2004-01-01

33

Human exploration mission studies  

NASA Technical Reports Server (NTRS)

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 presence into the solar system has particular significance, in that it defines long-range goals for NASA's future missions. To embark and achieve such ambitious ventures is a significant undertaking, particularly compared to past space activities. Missions to Mars, the Moon, and Phobos, as well as an observatory based on the dark side of the Moon are discussed.

Cataldo, Robert L.

1989-01-01

34

Limiter  

DOEpatents

A limiter with a specially contoured front face is provided. The front face of the limiter (the plasma-side face) is flat with a central indentation. In addition, the limiter shape is cylindrically symmetric so that the limiter can be rotated for greater heat distribution. This limiter shape accommodates the various power scrape-off distances lambda p, which depend on the parallel velocity, V/sub parallel/, of the impacting particles.

Cohen, S.A.; Hosea, J.C.; Timberlake, J.R.

1984-10-19

35

Using Load-Cells to Unveil Limitations to the Human  

E-print Network

at the Olympic games. Track and field athletes accomplish incredible force and speed performances when running year, athletes from all over the world demonstrate the boundaries of the human performance

Valero-Cuevas, Francisco

36

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

37

Peptide promotes overcoming of the division limit in human somatic cell.  

PubMed

We previously showed that treatment of normal human diploid cells with Epithalon (Ala-Glu-Asp-Gly) induced expression of telomerase catalytic subunit, its enzymatic activity, and elongation of telomeres. Here we studied the effect of this peptide on proliferative potential of human fetal fibroblasts. Primary pulmonary fibroblasts derived from a 24-week fetus lost the proliferative potential at the 34th passage. The mean size of telomeres in these cells was appreciably lower than during early passages (passage 10). Addition of Epithalon to aging cells in culture induced elongation of telomeres to the size comparable to their length during early passages. Peptide-treated cells with elongated telomeres made 10 extra divisions (44 passages) in comparison with the control and continued dividing. Hence, Epithalon prolonged the vital cycle of normal human cells due to overcoming the Heyflick limit. PMID:15455129

Khavinson, V Kh; Bondarev, I E; Butyugov, A A; Smirnova, T D

2004-05-01

38

Limiter  

DOEpatents

A limiter with a specially contoured front face accommodates the various power scrape-off distances .lambda..sub.p, which depend on the parallel velocity, V.sub..parallel., of the impacting particles. The front face of the limiter (the plasma-side face) is flat with a central indentation. In addition, the limiter shape is cylindrically symmetric so that the limiter can be rotated for greater heat distribution.

Cohen, Samuel A. (Hopewell, NJ); Hosea, Joel C. (Princeton, NJ); Timberlake, John R. (Allentown, NJ)

1986-01-01

39

Human immune system mice: current potential and limitations for translational research on human antibody responses.  

PubMed

It has recently become possible to generate chimeric mice durably engrafted with many components of the human immune system (HIS mice). We have characterized the maturation and function of the B cell compartment of HIS mice. The antibody response of HIS mice to T cell-dependent B cell antigens is limited, and contributing factors may be the general immaturity of the B cell compartment, infrequent helper T cells selected on human MHC class II antigens, and incomplete reconstitution of secondary lymphoid organs and their microenvironments. In contrast, HIS mice generate protective antibody responses to the bacterium Borrelia hermsii, which acts as a T cell-independent antigen in mice, but do not respond to purified polysaccharide antigens (PPS). We speculate that the anti-B. hermsii response of HIS mice is derived from an abundant B cell subset that may be analogous to B1 B cells in mice. We suggest that failure of HIS mice to respond to PPS is due to the lack of a B cell subset that may originate from adult bone marrow and is highly dependent on human interleukin-7 for development. PMID:22038527

Vuyyuru, Raja; Patton, John; Manser, Tim

2011-12-01

40

Uses and limitations of twin studies  

Microsoft Academic Search

Series of twin pairs selected because one (or both) is ill are prone to biassed ascertainment, and great care has to be taken to avoid this. Such bias is absent if the primary source is a twin registry established at birth. In general, series of twin pairs have no advantage over studies on sibs in assessing the size of genetic

Sarah Bundey

1991-01-01

41

Cardiovascular Deconditioning in Humans: Human Studies Core  

NASA Technical Reports Server (NTRS)

Major cardiovascular problems, secondary to cardiovascular deconditioning, may occur on extended space missions. While it is generally assumed that the microgravity state is the primary cause of cardiovascular deconditioning, sleep deprivation and disruption of diurnal rhythms may also play an important role. Factors that could be modified by either or both of these perturbations include: autonomic function and short-term cardiovascular reflexes, vasoreactivity, circadian rhythm of cardiovascular hormones (specifically the renin-angiotensin system) and renal sodium handling and hormonal influences on that process, venous compliance, cardiac mass, and cardiac conduction processes. The purpose of the Human Studies Core is to provide the infrastructure to conduct human experiments which will allow for the assessment of the likely role of such factors in the space travel associated cardiovascular deconditioning process and to develop appropriate countermeasures. The Core takes advantage of a newly-created Intensive Physiologic Monitoring (IPM) Unit at the Brigham and Women's Hospital, Boston, MA, to perform these studies. The Core includes two general experimental protocols. The first protocol involves a head down tilt bed-rest study to simulate microgravity. The second protocol includes the addition of a disruption of circadian rhythms to the simulated microgravity environment. Before and after each of these environmental manipulations, the subjects will undergo acute stressors simulating changes in volume and/or stress, which could occur in space and on return to Earth. The subjects are maintained in a rigidly controlled environment with fixed light/dark cycles, activity pattern, and dietary intake of nutrients, fluids, ions and calories.

Williams, Gordon

1999-01-01

42

A highly selective telomerase inhibitor limiting human cancer cell proliferation  

PubMed Central

Telomerase, the ribonucleoprotein enzyme maintaining the telomeres of eukaryotic chromosomes, is active in most human cancers and in germline cells but, with few exceptions, not in normal human somatic tissues. Telomere maintenance is essential to the replicative potential of malignant cells and the inhibition of telomerase can lead to telomere shortening and cessation of unrestrained proliferation. We describe novel chemical compounds which selectively inhibit telomerase in vitro and in vivo. Treatment of cancer cells with these inhibitors leads to progressive telomere shortening, with no acute cytotoxicity, but a proliferation arrest after a characteristic lag period with hallmarks of senescence, including morphological, mitotic and chromosomal aberrations and altered patterns of gene expression. Telomerase inhibition and telomere shortening also result in a marked reduction of the tumorigenic potential of drug-treated tumour cells in a mouse xenograft model. This model was also used to demonstrate in vivo efficacy with no adverse side effects and uncomplicated oral administration of the inhibitor. These findings indicate that potent and selective, non-nucleosidic telomerase inhibitors can be designed as novel cancer treatment modalities. PMID:11742973

Damm, Klaus; Hemmann, Ulrike; Garin-Chesa, Pilar; Hauel, Norbert; Kauffmann, Iris; Priepke, Henning; Niestroj, Claudia; Daiber, Christine; Enenkel, Barbara; Guilliard, Bernd; Lauritsch, Ines; Muller, Elfriede; Pascolo, Emanuelle; Sauter, Gabriele; Pantic, Milena; Martens, Uwe M.; Wenz, Christian; Lingner, Joachim; Kraut, Norbert; Rettig, Wolfgang J.; Schnapp, Andreas

2001-01-01

43

A highly selective telomerase inhibitor limiting human cancer cell proliferation.  

PubMed

Telomerase, the ribonucleoprotein enzyme maintaining the telomeres of eukaryotic chromosomes, is active in most human cancers and in germline cells but, with few exceptions, not in normal human somatic tissues. Telomere maintenance is essential to the replicative potential of malignant cells and the inhibition of telomerase can lead to telomere shortening and cessation of unrestrained proliferation. We describe novel chemical compounds which selectively inhibit telomerase in vitro and in vivo. Treatment of cancer cells with these inhibitors leads to progressive telomere shortening, with no acute cytotoxicity, but a proliferation arrest after a characteristic lag period with hallmarks of senescence, including morphological, mitotic and chromosomal aberrations and altered patterns of gene expression. Telomerase inhibition and telomere shortening also result in a marked reduction of the tumorigenic potential of drug-treated tumour cells in a mouse xenograft model. This model was also used to demonstrate in vivo efficacy with no adverse side effects and uncomplicated oral administration of the inhibitor. These findings indicate that potent and selective, non-nucleosidic telomerase inhibitors can be designed as novel cancer treatment modalities. PMID:11742973

Damm, K; Hemmann, U; Garin-Chesa, P; Hauel, N; Kauffmann, I; Priepke, H; Niestroj, C; Daiber, C; Enenkel, B; Guilliard, B; Lauritsch, I; Müller, E; Pascolo, E; Sauter, G; Pantic, M; Martens, U M; Wenz, C; Lingner, J; Kraut, N; Rettig, W J; Schnapp, A

2001-12-17

44

Studies That Observe Humans  

MedlinePLUS

... trying to guess at the cause and even writing about it as if the guess were fact. For instance, there were studies some years ago that linked gum disease with heart attacks. News reports talked about this link, with many theories about ...

45

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 choice…

Eriksson, Marten; Westerlund, Monica; Miniscalco, Carmela

2010-01-01

46

47 CFR 5.93 - Limited market studies.  

Code of Federal Regulations, 2010 CFR

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

2010-10-01

47

Utility, limitations, and future of non-human primates for dengue research and vaccine development.  

PubMed

Dengue is considered the most important emerging, human arboviruses, with worldwide distribution in the tropics. Unfortunately, there are no licensed dengue vaccines available or specific anti-viral drugs. The development of a dengue vaccine faces unique challenges. The four serotypes co-circulate in endemic areas, and pre-existing immunity to one serotype does not protect against infection with other serotypes, and actually may enhance severity of disease. One foremost constraint to test the efficacy of a dengue vaccine is the lack of an animal model that adequately recapitulates the clinical manifestations of a dengue infection in humans. In spite of this limitation, non-human primates (NHP) are considered the best available animal model to evaluate dengue vaccine candidates due to their genetic relatedness to humans and their ability to develop a viremia upon infection and a robust immune response similar to that in humans. Therefore, most dengue vaccines candidates are tested in primates before going into clinical trials. In this article, we present a comprehensive review of published studies on dengue vaccine evaluations using the NHP model, and discuss critical parameters affecting the usefulness of the model. In the light of recent clinical data, we assess the ability of the NHP model to predict immunological parameters of vaccine performances in humans and discuss parameters that should be further examined as potential correlates of protection. Finally, we propose some guidelines toward a more standardized use of the model to maximize its usefulness and to better compare the performance of vaccine candidates from different research groups. PMID:25309540

Sariol, Carlos A; White, Laura J

2014-01-01

48

Utility, Limitations, and Future of Non-Human Primates for Dengue Research and Vaccine Development  

PubMed Central

Dengue is considered the most important emerging, human arboviruses, with worldwide distribution in the tropics. Unfortunately, there are no licensed dengue vaccines available or specific anti-viral drugs. The development of a dengue vaccine faces unique challenges. The four serotypes co-circulate in endemic areas, and pre-existing immunity to one serotype does not protect against infection with other serotypes, and actually may enhance severity of disease. One foremost constraint to test the efficacy of a dengue vaccine is the lack of an animal model that adequately recapitulates the clinical manifestations of a dengue infection in humans. In spite of this limitation, non-human primates (NHP) are considered the best available animal model to evaluate dengue vaccine candidates due to their genetic relatedness to humans and their ability to develop a viremia upon infection and a robust immune response similar to that in humans. Therefore, most dengue vaccines candidates are tested in primates before going into clinical trials. In this article, we present a comprehensive review of published studies on dengue vaccine evaluations using the NHP model, and discuss critical parameters affecting the usefulness of the model. In the light of recent clinical data, we assess the ability of the NHP model to predict immunological parameters of vaccine performances in humans and discuss parameters that should be further examined as potential correlates of protection. Finally, we propose some guidelines toward a more standardized use of the model to maximize its usefulness and to better compare the performance of vaccine candidates from different research groups. PMID:25309540

Sariol, Carlos A.; White, Laura J.

2014-01-01

49

Experimental Study of Delay Effects on Coupled Limit Cycle Oscillators  

E-print Network

Chapter 5 Experimental Study of Delay Effects on Coupled Limit Cycle Oscillators "There is nothing Ph.D. thesis Title of thesis: Collective Dynamics of delay coupled oscillators Work done at on the collective behavior of coupled limit cycle oscillators we have also carried out a set of experimental studies

Dodla, Ramana

50

Safe human exposure limits for airborne linear siloxanes during spaceflight  

PubMed Central

Background Low molecular weight siloxanes are used in industrial processes and consumer products, and their vapors have been detected in the atmospheres of the Space Shuttle and International Space Station. Therefore, the National Aeronautics and Space Administration (NASA) developed spacecraft maximum allowable concentrations (SMACs) for siloxane vapors to protect astronaut health. Since publication of these original SMACs, new studies and new risk assessment approaches have been published that warrant re-examination of the SMACs. Objective To reevaluate SMACs published for octamethyltrisiloxane (L3) for exposures ranging from 1 hour to 180 days, to develop a 1000-day SMAC, and to expand the applicability of those values to the family of linear siloxanes. Methods A literature review was conducted to identify studies conducted since the SMACs for L3 were set in 1994. The updated data were reviewed to determine the sensitive toxicity endpoints, and current risk assessment approaches and methods for dosimetric adjustments were evaluated. Results Recent data were used to update the original 1-hour, 24-hour, 30-day, and 180-day SMACs for L3, and a 1000-day SMAC was developed to protect crewmembers during future exploration beyond Earth orbit. Group SMACs for the linear siloxane family, including hexamethyldisiloxane (L2), L3, decamethyltetrasiloxane (L4), and dodecamethylpentasiloxane (L5), were set for exposures of 1-hour to 1000 days. Conclusion New SMACs, based on acute pulmonary and neurotoxicity at high doses only achievable with L2 and potential liver effects following longer-term exposures to L2 and L3, were established to protect crewmembers from the adverse effects of exposure to linear siloxanes. PMID:24255951

Garcia, Hector D.; McMullin, Tami S.; Tobin, Joseph M.; James, John T.

2013-01-01

51

Limitations to the study of man in space in the U.S. space program  

NASA Technical Reports Server (NTRS)

Research on humans conducted during spaceflight is fraught both with great opportunities and great obstacles. The purpose of this paper is to review some of the limitations to research in space in the United States with hope that an informed scientific community may lead to more rapid and efficient solution of these problems. Limitations arise because opportunities to study the same astronauts in well-controlled situations on repeated spaceflights are practically non-existent. Human research opportunities are further limited by the necessity of avoiding simultaneous mutually-interfering experiments. Environmental factors, including diet and other physiological perturbations concomitant with spaceflight, also complicate research design and interpretation. Technical limitations to research methods and opportunities further restrict the development of the knowledge base. Finally, Earth analogues of space travel all suffer from inadequacies. Though all of these obstacles will eventually be overcome, creativity, diligence, and persistence are required to further our knowledge of humans in space.

Bishop, Phillip A.; Greenisen, Mike

1993-01-01

52

Limitations to the study of man in the United States space program  

NASA Technical Reports Server (NTRS)

Research on humans conducted during space flight is fraught both with great opportunities and great obstacles. The purpose of this paper is to review some of the limitations to United States research in space in the hope that an informed scientific community may lead to more rapid and efficient solution of these problems. Limitations arise because opportunities to study the same astronauts in well-controlled situations on repeated space flights are practically non-existent. Human research opportunities are further limited by the necessity of avoiding simultaneous mutually-interfereing experiments. Environmental factors including diet and other physiological perturbations concomitant with space flight also complicates research design and interpretation. Technical limitations to research methods and opportunities further restrict the development of the knowledge base. Finally, earth analogues of space travel all suffer from inadequacies. Though all of these obstacles will eventually be overcome; creativity, diligence, and persistence are required to further our knowledge of humans in space.

Bishop, Phillip A.; Greenisen, Mike

1992-01-01

53

A Dual Reporter Mouse Model of the Human ?-Globin Locus: Applications and Limitations  

PubMed Central

The human ?-globin locus contains the ?-like globin genes (i.e. fetal ?-globin and adult ?-globin), which heterotetramerize with ?-globin subunits to form fetal or adult hemoglobin. Thalassemia is one of the commonest inherited disorders in the world, which results in quantitative defects of the globins, based on a number of genome variations found in the globin gene clusters. Hereditary persistence of fetal hemoglobin (HPFH) also caused by similar types of genomic alterations can compensate for the loss of adult hemoglobin. Understanding the regulation of the human ?-globin gene expression is a challenge for the treatment of thalassemia. A mouse model that facilitates high-throughput assays would simplify such studies. We have generated a transgenic dual reporter mouse model by tagging the ?- and ?-globin genes with GFP and DsRed fluorescent proteins respectively in the endogenous human ?-globin locus. Erythroid cell lines derived from this mouse model were tested for their capacity to reactivate the ?-globin gene. Here, we discuss the applications and limitations of this fluorescent reporter model to study the genetic basis of red blood cell disorders and the potential use of such model systems in high-throughput screens for hemoglobinopathies therapeutics. PMID:23272095

Papadopoulos, Petros; Gutierrez, Laura; van der Linden, Reinier; Kong-A-San, John; Maas, Alex; Drabek, Dubravka; Patrinos, George P.; Philipsen, Sjaak; Grosveld, Frank

2012-01-01

54

Working Memory: A Cognitive Limit to Non-Human Primate Recursive Thinking Prior to Hominid Evolution?  

Microsoft Academic Search

In this paper I explore the possibility that recursion is not part of the cognitive repertoire of non-human primates due to a limitation on the size of working memory in non-human primates such as the chimpanzees. Multiple lines of data imply that chimpanzee working memory may be of size 2. If so, they lack the cognitive capacity for recursive thinking.

Dwight W. Read

55

Endocasts: possibilities and limitations for the interpretation of human brain evolution.  

PubMed

Brains are not preserved in the fossil record but endocranial casts are. These are casts of the internal bony braincase, revealing approximate brain size and shape, and they are also informative about brain surface morphology. Endocasts are the only direct evidence of human brain evolution, but they provide only limited data ('paleoneurology'). This review discusses some new fossil endocasts and recent methodological advances that have allowed novel analyses of old endocasts, leading to intriguing findings and hypotheses. The interpretation of paleoneurological data always relies on comparative information from living species whose brains and behavior can be directly investigated. It is therefore important that future studies attempt to better integrate different approaches. Only then will we be able to gain a better understanding about hominin brain evolution. © 2014 S. Karger AG, Basel. PMID:25247826

Neubauer, Simon

2014-01-01

56

Using diagnostic radiology in human evolutionary studies  

PubMed Central

This paper reviews the application of medical imaging and associated computer graphics techniques to the study of human evolutionary history, with an emphasis on basic concepts and on the advantages and limitations of each method. Following a short discussion of plain film radiography and pluridirectional tomography, the principles of computed tomography (CT) and magnetic resonance imaging (MRI) and their role in the investigation of extant and fossil morphology are considered in more detail. The second half of the paper deals with techniques of 3-dimensional visualisation based on CT and MRI and with quantitative analysis of digital images. PMID:10999271

SPOOR, FRED; JEFFERY, NATHAN; ZONNEVELD, FRANS

2000-01-01

57

Study of Danjon limit in moon crescent sighting  

NASA Astrophysics Data System (ADS)

About 70 years ago "André Danjon" a French astrophysicist showed that as elongation of the moon decreases the arc length of crescent gets less too. By studying the recent observational data, he concluded that at 7 degree elongation, the length of arc (cusp to cusp) will reach zero degree. Today, this value is named as Danjon limit, which points to the limit at which the moon crescent is formed. Danjon believed that the effective factor for occurring this limit was the shadows of moon's mountains. Later researchers have obtained different values for this limit. In this research based on the new data, the decreasing dependence of length of arc versus elongation was obtained. The results show that the Danjon limit is about 5 degrees. The effective factors to form the Danjon limit are then given and discussed. By considering the effects of astronomical seeing and shadows of lunar features, the values of the arc length were calculated and compared with the observational data curve. The results of this study show good agreement with the observational data. The present research shows that the above-mentioned effects can reduce the length of arc. The effect of libration and roughness of the lunar terrain of the moon in forming the moon crescent were also considered, and the possibility of observing thinner crescents by photometric model and breaking the Danjon limit were given.

Hasanzadeh, Amir

2012-06-01

58

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

59

Physical performance limitations in the Childhood Cancer Survivor Study cohort.  

PubMed

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. PMID:19332713

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

2009-05-10

60

German Studies, Culture Studies, and Institutional Structure: Possibilities and Limitations.  

ERIC Educational Resources Information Center

Focuses on the international and engineering program at the University of Rhode Island. Set against the background of revision of German studies that has taken place over the last several years, the program provides an example of successful alliance of language with a scientific program. This alliance has combined richness, rigor,…

Kirchner, Doris

1999-01-01

61

SANTA CREEK, BENEWAH COUNTY, IDAH - EFFLUENT LIMITATION STUDY. 1986  

EPA Science Inventory

A water quality study was initiated on Santa Creek, Idaho (17010304) to determine if new effluent limitations are necessary for the discharge from the City of Emida wastewater lagoon. The City of Emida provides secondary treatment of domestic sewage in an unaerated facultative l...

62

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

63

A novel mouse model for Down syndrome that harbor a single copy of human artificial chromosome (HAC) carrying a limited number of genes from human chromosome 21.  

PubMed

Down syndrome (DS), also known as Trisomy 21, is the most common chromosome aneuploidy in live-born children and displays a complicated symptom. To date, several kinds of mouse models have been generated to understand the molecular pathology of DS, yet the gene dosage effects and gene(s)-phenotype(s) correlation are not well understood. In this study, we established a novel method to generate a partial trisomy mice using the mouse ES cells that harbor a single copy of human artificial chromosome (HAC), into which a small human DNA segment containing human chromosome 21 genes cloned in a bacterial artificial chromosome (BAC) was recombined. The produced mice were found to maintain the HAC carrying human genes as a mini-chromosome, hence termed as a Trans-Mini-Chromosomal (TMC) mouse, and HAC was transmitted for more than twenty generations independent from endogenous mouse chromosomes. The three human transgenes including cystathionine ?-synthase, U2 auxiliary factor and crystalline alpha A were expressed in several mouse tissues with various expression levels relative to mouse endogenous genes. The novel system is applicable to any of human and/or mouse BAC clones. Thus, the TMC mouse carrying a HAC with a limited number of genes would provide a novel tool for studying gene dosage effects involved in the DS molecular pathogenesis and the gene(s)-phenotype(s) correlation. PMID:24293126

Miyamoto, Kenichi; Suzuki, Nobutaka; Sakai, Kosuke; Asakawa, Shuichi; Okazaki, Tsuneko; Kudoh, Jun; Ikeno, Masashi; Shimizu, Nobuyoshi

2014-04-01

64

Biofuels: Efficiency, Ethics, and Limits to Human Appropriation of Ecosystem Services  

Microsoft Academic Search

Biofuels have lately been indicated as a promising source of cheap and sustainable energy. In this paper we argue that some\\u000a important ethical and environmental issues have also to be addressed: (1) the conflict between biofuels production and global\\u000a food security, particularly in developing countries, and (2) the limits of the Human Appropriation of ecosystem services and\\u000a Net Primary Productivity.

Tiziano GomieroMaurizio; Maurizio G. Paoletti; David Pimentel

2010-01-01

65

When to start antiretroviral therapy in resource-limited settings: a human rights analysis  

PubMed Central

Background Recent evidence from developed and developing countries shows clear clinical and public health benefit to starting antiretroviral therapy (ART) earlier. While discussions about when to start ART have often focused on the clinical risks and benefits, the main issue is one of fair limit-setting. We applied a human rights framework to assess a policy of early treatment initiation according to the following criteria: public-health purpose; likely effectiveness; specificity; human rights burdens and benefits; potential for less restrictive approaches; and fair administration. Discussion According to our analysis, a policy of earlier ART initiation would better serve both public health and human rights objectives. We highlight a number of policy approaches that could be taken to help meet this aim, including increased international financial support, alternative models of care, and policies to secure the most affordable sources of appropriate antiretroviral drugs. Summary Widespread implementation of earlier ART initiation is challenging in resource-limited settings. Nevertheless, rationing of essential medicines is a restriction of human rights, and the principle of least restriction serves to focus attention on alternative measures such as adapting health service models to increase capacity, decreasing costs, and seeking additional international funding. Progressive realisation using well-defined steps will be necessary to allow for a phased implementation as part of a framework of short-term targets towards nationwide policy adoption, and will require international technical and financial support. PMID:20356356

2010-01-01

66

Initiation of Antiretroviral Treatment with Dual Nucleoside Reverse Transcriptase Inhibitors in Human Immunodeficiency Virus-Infected Infants with Less Advanced Disease in a Resource-Limited Setting: A MultiCenter Study in Thailand 1998-2000  

Microsoft Academic Search

Objectives: To evaluate the feasibility, duration of efficacy, and outcome of therapy with dual nucleoside reverse transcriptase inhibitors (NTRI) initiated in HIV-infected infants with mild to moderate disease. Material and Method: During 1998-2000, a multi-center prospective open-labeled operational study was conducted. Antiretroviral nao^ve HIV-infected infants were enrolled in seven hospitals to receive either zidovudine (AZT) plus lamivudine (3TC) or AZT

Kulkanya Chokephaibulkit; Nirun Vanprapar; Ruengpung Sutthent; Tawee Chotpitayasunondh; Piyaporn Bowornkitikajorn; Rudeevilai Samkoset; Uraiwan Tarunothai; Sanay Chearskul

67

Cerebellar lesion studies of cognitive function in children and adolescents — limitations and negative findings  

Microsoft Academic Search

An increasing number of human lesion and functional brain imaging studies appear to support the hypothesis that the cerebellum\\u000a contributes to a wide range of non-motor functions, including attention, language and visuospatial functions. Various abnormalities\\u000a have been reported in standard neuropsychological tests in children and adolescents who have been treated for cerebellar tumors.\\u000a This review focuses on limitations of lesion

Benedikt Frank; Beate Schoch; Stefanie Richter; Markus Frings; Hans-Otto Karnath; Dagmar Timmann

2007-01-01

68

Mockups and human productivity studies  

NASA Technical Reports Server (NTRS)

Idea outlines are presented concerning mockup candidates, mockup utilization and schedules/sequence in mockup development. Mockup candidates which aid in human productivity investigations and assessment are given. Areas which are considered in the mockups are the safe haven zone, general purpose workstations, maintenance and servicing area, sleep quaters, multiple docking adapter, airlock, hygiene station, food station, habitation zones, group gathering area and lab areas. Some aesthetic concerns in human productivity are also given.

Fisher, T.

1985-01-01

69

IMMUNOCHEMICAL STUDIES ON THE HUMAN SKIN LYSOZYME  

Microsoft Academic Search

Rabbit antiserum was prepared against crystalline hen egg white and human milk lysozymes. The immunological cross-reactions among egg white lysozyme and human lysozymes (skin, milk, leucocyte and crude tears) were studied by the qualitative gel diffusion precipitation technique and quantitative neutralization test using anti-E.W.L. Serum and anti-H.M.L. Serum. Immunological identity of the human skin lysozyme with both the human milk

Hideoki Ogawa; Hiroaki Miyazaki

1972-01-01

70

Limitations of wind power availability over Europe: a conceptual study  

NASA Astrophysics Data System (ADS)

Wind field statistics are evaluated from the ERA-40 data bank covering a period of 44 years with a temporal resolution of 6 h. Instantaneous wind speed values are provided in geographic cells of size 1°×1° (lat/long) for surface (10 m) and 1000 hPa pressure heights. Potential wind power generation is estimated in two steps. Firstly, the wind speed at hub height is approximated from surface data based on the statistical analysis of the wind and geopotential records for 1000 hPa pressure level. Secondly, the wind speed values are transformed by an idealised power curve fitted for measured data. The model time series are fed into various hypothetical electric networks. The main quantity of interest is the aggregated output from the networks. A reference power time series is determined for a static network connecting each continental site and an envelope of 1° around the shorelines (representing off-shore locations) over Europe. This time series exhibits a low average value and a marked annual periodicity. Wind power integration over limited areas results in higher average outputs at the expense of stronger fluctuations. The long-range spatial correlations of the wind field limit the level of fluctuations strongly which can not be eliminated either by an increase of the area of integration or by dynamic control. This study is fully conceptual, however it demonstrates the limitations of wind power integration over Europe.

Kiss, P.; Jánosi, I. M.

2008-11-01

71

Studies on Human Platelet Gangliosides  

PubMed Central

Gangliosides, glycosphingolipids which contain sialic acid, were studied in human platelets. They represented 0.5% of the platelet lipids and accounted for 6% of the total neuraminic acid content of platelets. Three major ganglioside fractions were identified and characterized. Ganglioside I was hematoside (G6) and comprised 92% of the platelet gangliosides. It contained glucose, galactose, and sialic acid in molar ratios of 1:1:1 and no hexosamine. The major fatty acid was behenate (22:0). Ganglioside I was also identified in isolated platelet granules and membranes. Ganglioside II (5%) contained glucose, galactose, sialic acid, and hexosamines (molar ratios 1:2:1:1). The hexosamines were glucosamine (72%) and galactosamine (28%). It was therefore designated as ganglioside lacto-N-neotetraose. Ganglioside III (2%) contained disialosyllactosyl ceramide (G3A) as well as two other gangliosides which could not be precisely characterized. Gangliosides I, II, and III were susceptible to the action of Clostridium perfringens neuraminidase as evidenced by full recovery of sialic acid in its free form after incubation. Neutral platelet glycolipids were qualitatively examined by thin-layer chromatography. The major component was lactosyl ceramide. Interactions of gangliosides I and III and serotonin-14C were examined in an equilibrium dialysis system at 4°C. The gangliosides bound serotonin-14C in relatively small quantities, whereas control lipids were negative. The binding was essentially unchanged by reverse dialysis, ultracentrifugation and subsequent thin-layer chromatography. The results are comparable to the previously observed nonmetabolic interactions between whole platelets and serotonin in the cold. It is suggested that the orientation and specific distribution of platelet membrane glycolipids may be important determinants of the unique surface properties of platelets. Images PMID:4341436

Marcus, Aaron J.; Ullman, Harris L.; Safier, Lenore B.

1972-01-01

72

Limiting factor analysis of high availability nuclear plants. Volume 3. Supplemental report, limiting valves study. Final report  

Microsoft Academic Search

Between January 1978 and February 1979, a study to identify operational, regulatory, maintenance, and design factors which limited plant performance was conducted at Turkey Point 3. During the Limiting Factor study period, field engineers stationed at the plant investigated the cause for each significant power reduction and quantified its impact on energy generated. Each event was categorized into one of

V. A. Paggen; T. L. Patterson; D. K. James; T. R. Reddaway

1979-01-01

73

The limitations of case-control studies in the detection of environmental carcinogens.  

PubMed Central

The ability of the case-control study to detect human carcinogens has been investigated theoretically for varying fractions of the population exposed to hazards carrying different relative risks. The method is shown to be useful for the investigation of factors to which exposure is widespread (for example, common foods or beverages) but it is of limited use for the study of uncommon types of exposure, such as those associated with occupation. The case-control study is unable to detect very small relative risks (less than 1.5) even where exposure is widespread and large numbers of cases of cancer are occurring in the population. The principal limitation of the method is the maximum number of cases which can be recruited and analysed. It will only be through large-scale collaborative multicentre or international studies that important risk factors will be detected. PMID:7338704

Crombie, I K

1981-01-01

74

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

75

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. PMID:23378896

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

2013-01-01

76

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

NASA Astrophysics Data System (ADS)

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.

Lü, Linyuan; Zhang, Zi-Ke; Zhou, Tao

2013-01-01

77

Deviation of Zipf's and Heaps' Laws in human languages with limited dictionary sizes.  

PubMed

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. PMID:23378896

Lü, Linyuan; Zhang, Zi-Ke; Zhou, Tao

2013-01-01

78

Interpreting Disasters From Limited Data Availability: A Guatemalan Study Case  

NASA Astrophysics Data System (ADS)

Guatemala is located in a geographical area exposed to multiple natural hazards. Although Guatemalan populations live in hazardous conditions, limited scientific research is being focused in this particular geographical area. Thorough studies are needed to understand the disasters occurring in the country and consequently enable decision makers and professionals to plan future actions, yet available data is limited. Data comprised in the available data sources is limited by their timespan or the size of the events included and therefore is insufficient to provide the whole picture of the disasters in the country. This study proposes a methodology to use the available data within one of the most important catchments in the country, the Samala River basin, to look for answers to what kind of disasters occurs? Where such events happen? And, why do they happen? Three datasets from different source agencies -one global, one regional, and one local- have been analyzed numerically and spatially using spreadsheets, numerical computing software, and geographic information systems. Analyses results have been coupled in order to search for possible answers to the established questions. It has been found a relation between the compositions of data of two of the three datasets analyzed. The third has shown a very different composition probably because the inclusion criteria of the dataset exclude smaller but more frequent disasters in its records. In all the datasets the most frequent type of disasters are those caused by hydrometeorological hazards i.e. floods and landslides. It has been found a relation between the occurrences of disasters and the records of precipitation in the area, but this relation is not strong enough to affirm that the disasters are the direct result of rain in the area and further studies must be carried out to explore other potential causes. Analyzing the existing data contributes to identify what kind of data is needed and this would be useful to feedback systems towards a collection of higher quality data, an increase in the capacity of studying disasters and improved risk management systems.

Soto Gomez, A.

2012-12-01

79

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

80

Similarity of polygenic profiles limits the potential for elite human physical performance  

PubMed Central

Human physical capability is influenced by many environmental and genetic factors, and it is generally accepted that physical capability phenotypes are highly polygenic. However, the ways in which relevant polymorphisms combine to influence the physical capability of individuals and populations are unknown. Initially, the literature was searched to identify associations between 23 genetic polymorphisms and human endurance phenotypes. Next, typical genotype frequencies of those polymorphisms in the general population were obtained from suitable literature. Using probability calculations, we found only a 0.0005% chance of a single individual in the world having the ‘preferable’ form of all 23 polymorphisms. As the number of DNA variants shown to be associated with human endurance phenotypes continues to increase, the probability of any single individual possessing the ‘preferable’ form of each polymorphism will become even lower. However, with population turnover, the chance of such genetically gifted individuals existing increases. To examine the polygenic endurance potential of a human population, a ‘total genotype score’ (for the 23 polymorphisms) was calculated for each individual within a hypothetical population of 1000 000. There was considerable homogeneity in terms of genetic predisposition to high endurance potential, with 99% of people differing by no more than seven genotypes from the typical profile. Consequently, with population turnover world and Olympic records should improve even without further enhancement of environmental factors, as more ‘advantageous’ polygenic profiles occasionally, though rarely, emerge. More broadly, human potential appears limited by the similarity of polygenic profiles at both the ‘elite sport’ and ‘chronic disorder’ ends of the performance continuum. PMID:17901117

Williams, Alun G; Folland, Jonathan P

2008-01-01

81

Religious Studies The School of Humanities  

E-print Network

222 Religious Studies The School of Humanities Chair William B. Parsons Professors Werner H. Kelber of religion) and religious traditions (African religions, Buddhism, Christianity, comparative religions, Islam defined fields, students acquire a broad knowledge of religious studies with enough flexibility

Richards-Kortum, Rebecca

82

Religious Studies The School of Humanities  

E-print Network

270 Religious Studies The School of Humanities Degrees Offered: BA, PhD The undergraduate major of religion) and religious traditions (African religions, Buddhism, Christianity, comparative religions fields, students acquire a broad knowledge of religious studies with enough flexibility

Richards-Kortum, Rebecca

83

Religious Studies The School of Humanities  

E-print Network

259 Religious Studies The School of Humanities Degrees Offered: BA, PhD The undergraduate major of religion) and religious traditions (African religions, Buddhism, Christianity, comparative religions fields, students acquire a broad knowledge of religious studies with enough flexibility

Richards-Kortum, Rebecca

84

Religious Studies The School of Humanities  

E-print Network

Religious Studies The School of Humanities Degrees Offered: BA, PhD The undergraduate major of religion) and religious traditions (African religions, Buddhism, Christianity, comparative religions fields, students acquire a broad knowledge of religious studies with enough flexibility

Richards-Kortum, Rebecca

85

Religious Studies The School of Humanities  

E-print Network

1 Religious Studies The School of Humanities Degrees Offered: BA, PhD The undergraduate major of religion) and religious traditions (African religions, Buddhism, Christianity, comparative religions fields, students acquire a broad knowledge of religious studies with enough flexibility

Richards-Kortum, Rebecca

86

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. PMID:22360847

2012-01-01

87

Potential and Limitation of HLA-Based Banking of Human Pluripotent Stem Cells for Cell Therapy  

PubMed Central

Great hopes have been placed on human pluripotent stem (hPS) cells for therapy. Tissues or organs derived from hPS cells could be the best solution to cure many different human diseases, especially those who do not respond to standard medication or drugs, such as neurodegenerative diseases, heart failure, or diabetes. The origin of hPS is critical and the idea of creating a bank of well-characterized hPS cells has emerged, like the one that already exists for cord blood. However, the main obstacle in transplantation is the rejection of tissues or organ by the receiver, due to the three main immunological barriers: the human leukocyte antigen (HLA), the ABO blood group, and minor antigens. The problem could be circumvented by using autologous stem cells, like induced pluripotent stem (iPS) cells, derived directly from the patient. But iPS cells have limitations, especially regarding the disease of the recipient and possible difficulties to handle or prepare autologous iPS cells. Finally, reaching standards of good clinical or manufacturing practices could be challenging. That is why well-characterized and universal hPS cells could be a better solution. In this review, we will discuss the interest and the feasibility to establish hPS cells bank, as well as some economics and ethical issues. PMID:25126584

Villard, Jean

2014-01-01

88

Potential and limitation of HLA-based banking of human pluripotent stem cells for cell therapy.  

PubMed

Great hopes have been placed on human pluripotent stem (hPS) cells for therapy. Tissues or organs derived from hPS cells could be the best solution to cure many different human diseases, especially those who do not respond to standard medication or drugs, such as neurodegenerative diseases, heart failure, or diabetes. The origin of hPS is critical and the idea of creating a bank of well-characterized hPS cells has emerged, like the one that already exists for cord blood. However, the main obstacle in transplantation is the rejection of tissues or organ by the receiver, due to the three main immunological barriers: the human leukocyte antigen (HLA), the ABO blood group, and minor antigens. The problem could be circumvented by using autologous stem cells, like induced pluripotent stem (iPS) cells, derived directly from the patient. But iPS cells have limitations, especially regarding the disease of the recipient and possible difficulties to handle or prepare autologous iPS cells. Finally, reaching standards of good clinical or manufacturing practices could be challenging. That is why well-characterized and universal hPS cells could be a better solution. In this review, we will discuss the interest and the feasibility to establish hPS cells bank, as well as some economics and ethical issues. PMID:25126584

de Rham, Casimir; Villard, Jean

2014-01-01

89

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

PubMed Central

Background Giardia 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 still needs to be proven. We tried to link different assemblages and sub-assemblages of G. intestinalis isolates from Swedish human patients to clinical symptoms and zoonotic transmission. Methodology/Principal Findings Multilocus sequence-based genotyping of 207 human Giardia isolates using three gene loci: ß-giardin, glutamate dehydrogenase (gdh), and triose phosphate isomerase (tpi) was combined with assemblage-specific tpi PCRs. This analysis identified 73 patients infected with assemblage A, 128 with assemblage B, and six with mixed assemblages A+B. Multilocus genotypes (MLGs) were easily determined for the assemblage A isolates, and most patients with this genotype had apparently been infected through anthroponotic transmission. However, we also found evidence of limited zoonotic transmission of Giardia in Sweden, since a few domestic human infections involved the same assemblage A MLGs previously reported in Swedish cats and ruminants. Assemblage B was detected more frequently than assemblage A and it was also more common in patients with suspected treatment failure. However, a large genetic variability made determination of assemblage B MLGs problematic. Correlation between symptoms and assemblages was found only for flatulence, which was significantly more common in children less than six years of age infected with assemblage B. Conclusions/Significance This study shows that certain assemblage A subtypes are potentially zoonotic and that flatulence is connected to assemblage B infections in young children. Determination of MLGs from assemblages A and B can be a valuable tool in outbreak situations and to help identify possible zoonotic transmission. PMID:21829745

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

2011-01-01

90

Plasma Limiter Studies at the Maryland Centrifugal Experiment  

NASA Astrophysics Data System (ADS)

An annular limiter experiment is being designed and constructed at the Maryland Centrifugal Experiment (MCX). This experiment has been motivated by the improved performance of the Gas Dynamic Trap using a biased limiter to induce vortex flows [A. A. Ivanov, et al. paper IAEA-CN-94/EX/P5-12 at Conference ``Fusion Energy-2002'']. The limiter may be biased with respect to the MCX vacuum vessel to attempt control over the radial electric field at the plasma edge. Measurements of the radial electric field in the edge region are planned using a Langmuir probe. Early results on the limiter's effects on MCX's performance will be reported.

Reid, R. R.; Young, W. C.; Romero-Talamas, C. A.; Taylor, G.; Ellis, R. F.; Hassam, A. B.

2010-11-01

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

Pcof. John Marino HUMANITIES 3 STUDY GUIDE  

E-print Network

~ College Humanities sequ~nce integrates history, literature, and philosophy m a five-_guarter chronological, and the crisis in European culture smce 1848. Revelle Humanities measures critical thinking by good writing. Just writing and thinking in concrete, commonly understandable realities. We are not studying rhetorical

Russell, Lynn

93

Studying dialects to understand human language  

E-print Network

This thesis investigates the study of dialect variations as a way to understand how humans might process speech. It evaluates some of the important research in dialect identification and draws conclusions about how their ...

Nti, Akua Afriyie

2009-01-01

94

Nutrient Limitation Governs Staphylococcus aureus Metabolism and Niche Adaptation in the Human Nose  

PubMed Central

Colonization of the human nose by Staphylococcus aureus in one-third of the population represents a major risk factor for invasive infections. The basis for adaptation of S. aureus to this specific habitat and reasons for the human predisposition to become colonized have remained largely unknown. Human nasal secretions were analyzed by metabolomics and found to contain potential nutrients in rather low amounts. No significant differences were found between S. aureus carriers and non-carriers, indicating that carriage is not associated with individual differences in nutrient supply. A synthetic nasal medium (SNM3) was composed based on the metabolomics data that permits consistent growth of S. aureus isolates. Key genes were expressed in SNM3 in a similar way as in the human nose, indicating that SNM3 represents a suitable surrogate environment for in vitro simulation studies. While the majority of S. aureus strains grew well in SNM3, most of the tested coagulase-negative staphylococci (CoNS) had major problems to multiply in SNM3 supporting the notion that CoNS are less well adapted to the nose and colonize preferentially the human skin. Global gene expression analysis revealed that, during growth in SNM3, S. aureus depends heavily on de novo synthesis of methionine. Accordingly, the methionine-biosynthesis enzyme cysteine-?-synthase (MetI) was indispensable for growth in SNM3, and the MetI inhibitor DL-propargylglycine inhibited S. aureus growth in SNM3 but not in the presence of methionine. Of note, metI was strongly up-regulated by S. aureus in human noses, and metI mutants were strongly abrogated in their capacity to colonize the noses of cotton rats. These findings indicate that the methionine biosynthetic pathway may include promising antimicrobial targets that have previously remained unrecognized. Hence, exploring the environmental conditions facultative pathogens are exposed to during colonization can be useful for understanding niche adaptation and identifying targets for new antimicrobial strategies. PMID:24453967

Krismer, Bernhard; Liebeke, Manuel; Janek, Daniela; Nega, Mulugeta; Rautenberg, Maren; Hornig, Gabriele; Unger, Clemens; Weidenmaier, Christopher; Lalk, Michael; Peschel, Andreas

2014-01-01

95

Stimulators of Mineralization Limit the Invasive Phenotype of Human Osteosarcoma Cells by a Mechanism Involving Impaired Invadopodia Formation  

PubMed Central

Background Osteosarcoma (OS) is a highly aggressive bone cancer affecting children and young adults. Growing evidence connects the invasive potential of OS cells with their ability to form invadopodia (structures specialized in extracellular matrix proteolysis). Results In this study, we tested the hypothesis that commonly used in vitro stimulators of mineralization limit the invadopodia formation in OS cells. Here we examined the invasive potential of human osteoblast-like cells (Saos-2) and osteolytic-like (143B) OS cells treated with the stimulators of mineralization (ascorbic acid and B-glycerophosphate) and observed a significant difference in response of the tested cells to the treatment. In contrast to 143B cells, osteoblast-like cells developed a mineralization phenotype that was accompanied by a decreased proliferation rate, prolongation of the cell cycle progression and apoptosis. On the other hand, stimulators of mineralization limited osteolytic-like OS cell invasiveness into collagen matrix. We are the first to evidence the ability of 143B cells to degrade extracellular matrix to be driven by invadopodia. Herein, we show that this ability of osteolytic-like cells in vitro is limited by stimulators of mineralization. Conclusions Our study demonstrates that mineralization competency determines the invasive potential of cancer cells. A better understanding of the molecular mechanisms by which stimulators of mineralization regulate and execute invadopodia formation would reveal novel clinical targets for treating osteosarcoma. PMID:25314307

Cmoch, Anna; Podszywalow-Bartnicka, Paulina; Palczewska, Malgorzata; Piwocka, Katarzyna; Groves, Patrick; Pikula, Slawomir

2014-01-01

96

14.3 HUMAN SUBJECTS RESEARCH The Colorado School of Mines limits all research involving human subjects, whether or not the research  

E-print Network

strategies, or (ii) research on the effectiveness of or the comparison among instructional techniques14.3 HUMAN SUBJECTS RESEARCH The Colorado School of Mines limits all research involving human subjects, whether or not the research is funded by external sponsors, to those projects approved in advance

97

47 CFR 5.93 - Limited market studies.  

Code of Federal Regulations, 2011 CFR

...licensee is responsible for informing anyone participating in the experiment that the service or device is granted under an experimental...is strictly temporary. (c) The size and scope of the experiment are subject to limitations as the Commission shall...

2011-10-01

98

To define the congruence of human population distribution and P. falciparum transmission we used spatially linked databases of human population, limits of malaria  

E-print Network

spatially linked databases of human population, limits of malaria risk and malaria endemicity within defined the spatial extent of P. falciparum risk by using the mapped global limits of malaria risk on the only available global map of malaria endemicity developed in 1968 (refs 6, 7). This map was part

Cai, Long

99

Limits of Human Performance. Annual Meeting (56th, Eugene, Oregon, July 19-26, 1984). American Academy of Physical Education Papers, No. 18.  

ERIC Educational Resources Information Center

The following papers are included in this collection: (1) "The Scientific Study of Athletes and Athletics" (Henry J. Montoye); (2) "The Limits of Human Performance" (David H. Clarke); (3) "Observations of Extraordinary Performances in an Extreme Environment and in a Training Environment" (E.R. Buskirk); (4) "Metabolic Requirements of Distance…

Clarke, David H., Ed.; Eckert, Helen M., Ed.

100

ACCEPTABLE HUMANITIES (HU) COURSES * African Studies  

E-print Network

ACCEPTABLE HUMANITIES (HU) COURSES * African Studies CAS AA 103 Introduction to African American Literature American & New England Studies CAS AM 200 Introduction to American Studies Archaeology CAS AR 100, 161, 162, 211, and 261 CAS CG 111. 112. 211 and 212 English Literature CAS EN 121 Readings in World

101

Multicenter Study of Limited Health Literacy in Emergency Department Patients  

Microsoft Academic Search

Objectives: The objective was to evaluate the prevalence of limited health literacy and its association with sociodemographic variables in emergency department (ED) patients. Methods: This was a cross-sectional survey in three Boston EDs. The authors enrolled consecutive adult patients during two 24-hour periods at each site. They measured health literacy by the short version of the Test of Functional Health

Adit A. Ginde; Scott G. Weiner; Daniel J. Pallin; Carlos A. Camargo Jr

2008-01-01

102

Background of Civil Defense and Current Damage Limiting Studies.  

ERIC Educational Resources Information Center

A brief history of civil defense administration precedes analysis of nuclear attack conditions and the influence of protective measures. Damage limitation procedure is explained in terms of--(1) blast effects, (2) radiation doses, (3) geographical fallout distribution patterns, and (4) national shelter needs. Major concept emphasis relates to--(1)…

Romm, Joseph

103

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. PMID:18171605

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

2008-01-01

104

The Viral E8^E2C Repressor Limits Productive Replication of Human Papillomavirus 16  

PubMed Central

Productive replication of human papillomavirus type 16 (HPV16) occurs only in differentiated keratinocyte cells. In addition to the viral E2 activator protein, HPV16 and related HPV types express transcripts coding for an E8^E2C fusion protein, which limits genome replication in undifferentiated keratinocytes. To address E8^E2C's role in productive replication of HPV16, stable keratinocyte cell lines containing wild-type (wt), E8^E2C knockout (E8?), or E8 KWK mutant (mt) genomes, in which conserved E8 residues were inactivated, were established. Copy numbers of E8? and E8 KWK mt genomes and amounts of early and late viral transcripts were greatly increased compared to those for the wt in undifferentiated keratinocytes, suggesting that HPV16 E8^E2C activities are highly dependent upon the E8 part. Upon differentiation in organotypic cultures, E8 mt genomes displayed higher early viral transcript levels, but no changes in cellular differentiation or virus-induced cellular DNA replication in suprabasal cells were observed. E8 mt genomes were amplified to higher copy numbers and showed increased L1 transcripts compared to wt genomes. Furthermore, the number of cells expressing the viral late protein E4 or L1 or amplifying viral genomes was greatly increased in E8 mt cell lines. In wild-type cells, E8^E2C transcript levels did not decrease by differentiation. Our data indicate that the E8^E2C repressor limits viral transcription and replication throughout the complete life cycle of HPV16. PMID:24198405

Straub, Elke; Dreer, Marcel; Fertey, Jasmin; Iftner, Thomas

2014-01-01

105

Molecular interaction networks for the analysis of human disease: utility, limitations, and considerations.  

PubMed

High-throughput '-omics' data can be combined with large-scale molecular interaction networks, for example, protein-protein interaction networks, to provide a unique framework for the investigation of human molecular biology. Interest in these integrative '-omics' methods is growing rapidly because of their potential to understand complexity and association with disease; such approaches have a focus on associations between phenotype and "network-type." The potential of this research is enticing, yet there remain a series of important considerations. Here, we discuss interaction data selection, data quality, the relative merits of using data from large high-throughput studies versus a meta-database of smaller literature-curated studies, and possible issues of sociological or inspection bias in interaction data. Other work underway, especially international consortia to establish data formats, quality standards and address data redundancy, and the improvements these efforts are making to the field, is also evaluated. We present options for researchers intending to use large-scale molecular interaction networks as a functional context for protein or gene expression data, including microRNAs, especially in the context of human disease. PMID:24166987

Schramm, Sarah-Jane; Jayaswal, Vivek; Goel, Apurv; Li, Simone S; Yang, Yee Hwa; Mann, Graham J; Wilkins, Marc R

2013-12-01

106

Potential and limitations of diffusion MRI tractography for the study of language.  

PubMed

Diffusion magnetic resonance imaging (MRI) is a tremendously promising tool for imaging tissue microstructure, and for inferring large scale structural connectivity in vivo. However, the sensitivity of the technique is highly dependent on methodological details. Acquisition parameters, pre-processing steps, reconstruction models, and statistical analysis all affect the final sensitivity, specificity, and accuracy of a study. In the case of fiber pathway reconstruction in the central nervous system, termed tractography, false positive and false negative results abound, and interpretation of results must take into account the potential shortcomings of the techniques used. This article will review the strengths and limitations of different types of diffusion MRI tractography analysis, and highlight what one can realistically hope to learn from such imaging studies of the human brain. PMID:23910928

Campbell, Jennifer S W; Pike, G Bruce

2014-04-01

107

Transient disruption of human pursuit-tracking performance for laser exposures below permissible exposure limits  

NASA Astrophysics Data System (ADS)

The proliferation of lasers for medical care, laser displays, industrial applications and audio- visual presentations has increased the potential for accidental intrabeam exposure to visible laser radiation. The output of these laser devices may be limited to below permissible exposure limits, but they are perceived as bright and can affect performance. The disruption experienced while viewing a laser is related to factors that include the retinal irradiance level, wavelength, ambient light level and mode (continuous wave (CW) and repetitively pulsed (RP)). This report describes studies where these factors were varied to assess the effects of laser light on tracking performance in a laboratory simulator and in a field study. Disruption was determined by measuring maximum error and total time off target. Performance disruption increased as irradiance levels increased and ambient light levels decreased.Under dawn/dusk conditions, relatively low-level laser energy produced performance disruption. Green laser light at the peak of the photopic sensitivity curve was more disruptive than red laser light. Increased error scores during CW and RP trials were attributed to average rather than peak power effects. More than 1500 laser exposures at levels up to MPE/2 have been given to volunteers. Despite transient performance disruption comparison of the pre- and post- laser visual performance tests and fundus evaluations wee unremarkable.

Stamper, David A.; Lund, David J.; Molchany, Jerome W.; Stuck, Bruce E.

1997-05-01

108

Communication: The Study of Human Interaction.  

ERIC Educational Resources Information Center

Designed to provide a comprehensive and broadly based introduction to the study of human communication, this book presents the concept of communication as interrelated constituent processes that operate at varying levels of complexity and acquire significance only in the context of larger intrapersonal, interpersonal, or socio-cultural systems of…

Mortensen, C. David

109

Optical limiting and thermal lensing studies in C60 S. S. Harilal,a)  

E-print Network

Optical limiting and thermal lensing studies in C60 S. S. Harilal,a) C. V. Bindhu, V. P. N 1999 Optical limiting and thermo-optic properties of C60 in toluene are studied using 532 nm, 9 ns pulses from a frequency-doubled Nd:YAG laser. Optical limiting studies in these fullerene molecules lead

Harilal, S. S.

110

Normal human alveolar macrophages obtained by bronchoalveolar lavage have a limited capacity to release interleukin-1.  

PubMed Central

Interleukin-1 (IL-1) is a mediator released by stimulated mononuclear phagocytes that is thought to play an important role in modulating T and B lymphocyte activation as well as in contributing to the febrile response and other inflammatory processes. Circulating mononuclear phagocytes, blood monocytes, readily release IL-1 when stimulated. However, the ability of lung mononuclear phagocytes, alveolar macrophages, to dispose of the large daily burden of inhaled antigens without stimulating an inflammatory response suggests that the release of IL-1 by alveolar macrophages may differ significantly from that of blood monocytes. To evaluate this hypothesis, normal autologous alveolar macrophages, obtained by bronchoalveolar lavage, were compared with blood monocytes for their ability to release IL-1 in response to a standard stimulus, lipopolysaccharide (LPS). Alveolar macrophages were found to be at least 1,000 times less sensitive to LPS than blood monocytes. Furthermore, alveolar macrophages released significantly less IL-1 than blood monocytes (26 +/- 11 vs. 128 +/- 21 U/10(6) cells X 24 h, respectively, after stimulation with 10 micrograms/ml of LPS, P less than 0.001). This difference was not due to the release of substances by macrophages, which inhibited lymphocyte proliferation in response to IL-1, or to degradation of IL-1 by macrophages. Culturing macrophages in the presence of indomethacin and dialysis of macrophage supernatants did not affect the difference, and culturing macrophages with monocytes did not decrease detectable IL-1 activity from the monocytes. The IL-1 produced by the two cell types was indistinguishable by anion-exchange chromatography, gel filtration, and isoelectric focusing. In addition, consistent with the findings for alveolar macrophages, macrophages generated by the in vitro maturation of blood monocytes were also deficient in their ability to release IL-1. These findings suggest that if the population of alveolar macrophages obtained by bronchoalveolar lavage represents the total in vivo population of alveolar macrophages, although normal human macrophages are capable of IL-1 release, they are relatively limited in this ability, and this limitation seems to be linked to the maturational state of the mononuclear phagocyte. These observations may explain, in part, the ability of alveolar macrophages to clear the airspaces of foreign antigens without extensive activation of other pulmonary inflammatory and immune effector cells. Images PMID:6334697

Wewers, M D; Rennard, S I; Hance, A J; Bitterman, P B; Crystal, R G

1984-01-01

111

Identification of host miRNAs that may limit human rhinovirus replication  

PubMed Central

AIM: To test whether the replication of human rhinovirus (HRV) is regulated by microRNAs in human bronchial epithelial cells. METHODS: For the present study, the human cell line BEAS-2B (derived from normal human bronchial epithelial cells) was adopted. DICER knock-down, by siRNA transfection in BEAS-2B cells, was performed in order to inhibit microRNA maturation globally. Alternatively, antisense oligonucleotides (anti-miRs) were transfected to inhibit the activity of specific microRNAs. Cells were infected with HRV-1B. Viral replication was assessed by measuring the genomic viral RNA by reverse transcription quantitative polymerase chain reaction (RT-qPCR). Association between microRNA-induced-silencing-complex and viral RNA was detected by Ago2 co-immunoprecipitation followed by RT-qPCR. Targetscan v.6 was used to predict microRNA target sites on several HRV strains. RESULTS: Here, we show that microRNAs affect replication of HRV-1B. DICER knock-down significantly reduced the expression of mature microRNAs in a bronchial epithelial cell line (BEAS-2B) and in turn, increased the synthesis of HRV-1B RNA. Additionally, HRV-1B RNA co-immunoprecipitated with argonaute 2 protein, an important effector for microRNA activity suggesting that microRNAs bind to viral RNA during infection. In order to identify specific microRNAs involved in this interaction, we employed bioinformatics analysis, and selected a group of microRNAs that have been reported to be under-expressed in asthmatic bronchial epithelial cells and were predicted to target different strains of rhinoviruses (HRV-1B, -16, -14, -27). Our results suggest that, out of this group of microRNAs, miR-128 and miR-155 contribute to the innate defense against HRV-1B: transfection of specific anti-miRs increased viral replication, as anticipated in-silico. CONCLUSION: Taken together, our results suggest that pathological changes in microRNA expression, as already reported for asthma or chronic obstructive pulmonary disease have the potential to affect Rhinovirus replication and therefore may play a role in virus-induced exacerbations.

Bondanese, Victor Paky; Francisco-Garcia, Ana; Bedke, Nicole; Davies, Donna E; Sanchez-Elsner, Tilman

2014-01-01

112

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

113

Limits to population size: Three scenarios of energy interaction between human society and ecosystem  

Microsoft Academic Search

A simple theoretical model describing the interaction between humans and their environment in terms of energy flows is proposed to check the compatibility between the density of energy throughput in human society and the density of energy throughput in the ecosystem. This model is then applied to analyze three different scenarios of energy interaction between human society and the ecosystem:

Mario Giampietro; Sandra G. F. Bukkens; David Pimentel

1992-01-01

114

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

PubMed Central

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 depends 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 Gmax = 300mT/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 minutes. 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 coils 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.

2013-01-01

115

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

2013-10-15

116

Human Transportation System (HTS) study, volume 1  

NASA Technical Reports Server (NTRS)

Work completed under the Human Transportation System Study is summarized. This study was conducted by the New Initiatives Office at JSC with the technical support of Boeing, General Dynamics, Lockheed, McDonnell-Douglas, Martin Marietta, and Rockwell. The study was designed to generate information on determining the appropriate path to follow for new system development to meet the Nation's space transportation needs. The study evaluates 18 transportation architecture options using a parametric set of mission requirements. These options include use of current systems as well as proposed systems to assess the impact of various considerations, such as the cost of alternate access, or the benefit of separating people and cargo. The architecture options are compared to each other with six measurable evaluation criteria or attributes. They are the following: funding profile, human safety, probability of mission success, architecture cost risk, launch schedule confidence, and environmental impact. Values for these attributes are presented for the architecture options, with pertinent conclusions and recommendations.

Lance, N.; Geyer, M. S.; Gaunce, M. T.

1993-01-01

117

Human Transportation System (HTS) study: Executive summary  

NASA Technical Reports Server (NTRS)

Work completed under the Human Transportation System Study is summarized. This study was conducted by the New Initiatives Office at JSC with the technical support of Boeing, General Dynamics, Lockheed, McDonnell-Douglas, Martin Marietta, and Rockwell. The study was designed to generate information on determining the appropriate path to follow for new system development to meet the Nation's space transportation needs. The study evaluates 18 transportation architecture options using a parametric set of mission requirements. These options include use of current systems as well as proposed systems to assess the impact of various considerations, such as the cost of alternate access, or the benefit of separating people and cargo. The architecture options are compared to each other with six measurable evaluation criteria or attributes. They are the following: funding profile, human safety, probability of mission success, architecture cost risk, launch schedule confidence, and environmental impact. Values for these attributes are presented for the architecture options, with pertinent conclusions and recommendations.

Lance, N.; Geyer, M. S.; Gaunce, M. T.

1993-01-01

118

Factors which Limit the Value of Additional Redundancy in Human Rated Launch Vehicle Systems  

NASA Technical Reports Server (NTRS)

The National Aeronautics and Space Administration (NASA) has embarked on an ambitious program to return humans to the moon and beyond. As NASA moves forward in the development and design of new launch vehicles for future space exploration, it must fully consider the implications that rule-based requirements of redundancy or fault tolerance have on system reliability/risk. These considerations include common cause failure, increased system complexity, combined serial and parallel configurations, and the impact of design features implemented to control premature activation. These factors and others must be considered in trade studies to support design decisions that balance safety, reliability, performance and system complexity to achieve a relatively simple, operable system that provides the safest and most reliable system within the specified performance requirements. This paper describes conditions under which additional functional redundancy can impede improved system reliability. Examples from current NASA programs including the Ares I Upper Stage will be shown.

Anderson, Joel M.; Stott, James E.; Ring, Robert W.; Hatfield, Spencer; Kaltz, Gregory M.

2008-01-01

119

Study on Optical Filter Heating in Background Limited Detector Experiments  

NASA Astrophysics Data System (ADS)

Cryogenic test setups with controlled stray light environments capable of reaching ultra-low radiative background levels are required to test far infrared (FIR) and submillimeter (sub-mm) wave radiation detectors for future space based observatories. In recent experiments (Nature Commun 5:3130, 2014), in which 1.54 THz radiation was coupled onto an antenna-coupled kinetic inductance detector (KID), we found a higher than expected optical loading. We show that this can be explained by assuming heating of the metal mesh IR filters and re-radiation onto the KID. Note that the total power from the cryogenic black body source used in the experiments (at T = - K) is much larger than the power inside the - THz band we use to calibrate our detector. The out-of-band radiation can have up to 5 orders of magnitude more power than inside the - THz band of interest. A strategy to mitigate the filter heating problem is presented, and when it is implemented, the validated upper limit for stray light at the detector level is down to few aW.

Bueno, J.; de Visser, P. J.; Doyle, S.; Baselmans, J. J. A.

2014-09-01

120

Year on year, competitive athletes confound our expecta-tions regarding the limits of human physical perform-  

E-print Network

both the mirror system and an expanded role for forward models, which includes predicting the sportingYear on year, competitive athletes confound our expecta- tions regarding the limits of human they allow more rigorous psychophysical characterization, computational modelling and brain-based hypothesis

Sergio, Lauren E.

121

Because of its limited computational capacity, the human brain does not fully process all of the information  

E-print Network

Because of its limited computational capacity, the human brain does not fully process all) called this phenomenon priming of pop-out (PoP). PoP does not passively encode all items appearing Society, Inc. Mechanisms of priming of pop-out: Stored representations or feature-gain modulations

Vecera, Shaun

122

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

NASA Astrophysics Data System (ADS)

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.

Rocha, Luis E. C.; Blondel, Vincent D.

2013-04-01

123

Selenium neurotoxicity in humans: bridging laboratory and epidemiologic studies.  

PubMed

Selenium is a metalloid of considerable interest in the human from both a toxicological and a nutritional perspective, with a very narrow safe range of intake. Acute selenium intoxication is followed by adverse effects on the nervous system with special clinical relevance, while the neurotoxicity of long-term overexposure is less characterized and recognized. We aimed to address this issue from a public health perspective, focusing on both laboratory studies and the few epidemiologic human studies available, with emphasis on their methodological strengths and limitations. The frequently overlooked differences in toxicity and biological activity of selenium compounds are also outlined. In addition to lethargy, dizziness, motor weakness and paresthesias, an excess risk of amyotrophic lateral sclerosis is the effect on the nervous system which has been more consistently associated with chronic low-level selenium overexposure, particularly to its inorganic compounds. Additional research efforts are needed to better elucidate the neurotoxic effects exerted by selenium overexposure. PMID:24269718

Vinceti, Marco; Mandrioli, Jessica; Borella, Paola; Michalke, Bernhard; Tsatsakis, Aristidis; Finkelstein, Yoram

2014-10-15

124

A Comparative Study of Limited Range Wavelength Conversion Policies for  

E-print Network

of bandwidth (as opposed to circuit­based networks): Optical Packet Switching (OPS) [5],[12] and Optical Burst/OBS, respectively. In synchronous (i.e., time­slotted) optical packet switching networks, packet lengths are fixed in this study to asynchronous optical packet switching. One major issue in optical packet switching networks

Akar, Nail

125

Sociology and American Studies: A Case Study in the Limits of Interdisciplinarity.  

PubMed

American Studies is an academic discipline whose object of study is the United States of America and everything associated with it, and American sociologists largely ignore it. American Studies largely ignores American sociology. What causes this mutual exclusion? An outline of the disciplinary history of American Studies and journal article citation data show that the relationship between sociology and American Studies is weak and asymmetrical; American Studies cites sociology more often, but very little and not by much. I argue that mutual exclusion is due to mutual distrust in methods: sociology sees itself as a science, while American Studies, with roots in history and literature, does not. This article serves as a case study in the limits of interdisciplinarity. PMID:22131556

Dubrow, Joshua Kjerulf

2011-12-01

126

Telomerase Inhibitor Imetelstat (GRN163L) Limits the Lifespan of Human Pancreatic Cancer Cells  

PubMed Central

Telomerase is required for the unlimited lifespan of cancer cells. The vast majority of pancreatic adenocarcinomas overexpress telomerase activity and blocking telomerase could limit their lifespan. GRN163L (Imetelstat) is a lipid-conjugated N3??P5? thio-phosphoramidate oligonucleotide that blocks the template region of telomerase. The aim of this study was to define the effects of long-term GRN163L exposure on the maintenance of telomeres and lifespan of pancreatic cancer cells. Telomere size, telomerase activity, and telomerase inhibition response to GRN163L were measured in a panel of 10 pancreatic cancer cell lines. The cell lines exhibited large differences in levels of telomerase activity (46-fold variation), but most lines had very short telomeres (2–3 kb in size). GRN163L inhibited telomerase in all 10 pancreatic cancer cell lines, with IC50 ranging from 50 nM to 200 nM. Continuous GRN163L exposure of CAPAN1 (IC50?=?75 nM) and CD18 cells (IC50?=?204 nM) resulted in an initial rapid shortening of the telomeres followed by the maintenance of extremely short but stable telomeres. Continuous exposure to the drug eventually led to crisis and to a complete loss of viability after 47 (CAPAN1) and 69 (CD18) doublings. Crisis In these cells was accompanied by activation of a DNA damage response (?-H2AX) and evidence of both senescence (SA-?-galactosidase activity) and apoptosis (sub-G1 DNA content, PARP cleavage). Removal of the drug after long-term GRN163L exposure led to a reactivation of telomerase and re-elongation of telomeres in the third week of cultivation without GRN163L. These findings show that the lifespan of pancreatic cancer cells can be limited by continuous telomerase inhibition. These results should facilitate the design of future clinical trials of GRN163L in patients with pancreatic cancer. PMID:24409321

Burchett, Katrina M.; Yan, Ying; Ouellette, Michel M.

2014-01-01

127

Telomerase inhibitor Imetelstat (GRN163L) limits the lifespan of human pancreatic cancer cells.  

PubMed

Telomerase is required for the unlimited lifespan of cancer cells. The vast majority of pancreatic adenocarcinomas overexpress telomerase activity and blocking telomerase could limit their lifespan. GRN163L (Imetelstat) is a lipid-conjugated N3'?P5' thio-phosphoramidate oligonucleotide that blocks the template region of telomerase. The aim of this study was to define the effects of long-term GRN163L exposure on the maintenance of telomeres and lifespan of pancreatic cancer cells. Telomere size, telomerase activity, and telomerase inhibition response to GRN163L were measured in a panel of 10 pancreatic cancer cell lines. The cell lines exhibited large differences in levels of telomerase activity (46-fold variation), but most lines had very short telomeres (2-3 kb in size). GRN163L inhibited telomerase in all 10 pancreatic cancer cell lines, with IC50 ranging from 50 nM to 200 nM. Continuous GRN163L exposure of CAPAN1 (IC50?=?75 nM) and CD18 cells (IC50?=?204 nM) resulted in an initial rapid shortening of the telomeres followed by the maintenance of extremely short but stable telomeres. Continuous exposure to the drug eventually led to crisis and to a complete loss of viability after 47 (CAPAN1) and 69 (CD18) doublings. Crisis In these cells was accompanied by activation of a DNA damage response (?-H2AX) and evidence of both senescence (SA-?-galactosidase activity) and apoptosis (sub-G1 DNA content, PARP cleavage). Removal of the drug after long-term GRN163L exposure led to a reactivation of telomerase and re-elongation of telomeres in the third week of cultivation without GRN163L. These findings show that the lifespan of pancreatic cancer cells can be limited by continuous telomerase inhibition. These results should facilitate the design of future clinical trials of GRN163L in patients with pancreatic cancer. PMID:24409321

Burchett, Katrina M; Yan, Ying; Ouellette, Michel M

2014-01-01

128

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. PMID:19880459

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

2013-01-01

129

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

130

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

131

Pooled biological specimens for human biomonitoring of environmental chemicals: opportunities and limitations.  

PubMed

Biomonitoring has become the "gold standard" in assessing chemical exposures, and has an important role in risk assessment. The pooling of biological specimens-combining multiple individual specimens into a single sample-can be used in biomonitoring studies to monitor levels of exposure and identify exposure trends or to identify susceptible populations in a cost-effective manner. Pooled samples provide an estimate of central tendency and may also reveal information about variation within the population. The development of a pooling strategy requires careful consideration of the type and number of samples collected, the number of pools required and the number of specimens to combine per pool in order to maximise the type and robustness of the data. Creative pooling strategies can be used to explore exposure-outcome associations, and extrapolation from other larger studies can be useful in identifying elevated exposures in specific individuals. The use of pooled specimens is advantageous as it saves significantly on analytical costs, may reduce the time and resources required for recruitment and, in certain circumstances, allows quantification of samples approaching the limit of detection. In addition, the use of pooled samples can provide population estimates while avoiding ethical difficulties that may be associated with reporting individual results. PMID:24192659

Heffernan, Amy L; Aylward, Lesa L; Toms, Leisa-Maree L; Sly, Peter D; Macleod, Matthew; Mueller, Jochen F

2014-01-01

132

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...

133

Limited Asymptomatic Carriage of Pneumocystis jiroveci in Human Immunodeficiency Virus–Infected Patients  

Microsoft Academic Search

Forty-seven bronchoalveolar lavage fluid samples from 16 human immunodeficiency virus (HIV)-infected patients were used to test the latency model of Pneumocystis infection in the human host. Identification of DNA sequence polymorphisms at 4 independent loci were used to genotype Pneumocystis jiroveci from the 35 samples that contained detectable P. jiroveci DNA. Eighteen of those 35 samples came from patients who

2003-01-01

134

Superior reproductive success on human blood without sugar is not limited to highly anthropophilic mosquito  

E-print Network

mosquito species M. A. H. BRAKS1 , S. A. JULIANO2 and L. P. LOUNIBOS1 1 Florida Medical Entomology stricto Giles may derive all adult energy requirements from human blood alone (Straif & Beier, 1996; Gary Rico showed that female Ae. aegypti fed predo- minantly on humans (Chow et al., 1993; Scott et al

Juliano, Steven A.

135

Formally verifying human-automation interaction as part of a system model: limitations and tradeoffs  

PubMed Central

Both the human factors engineering (HFE) and formal methods communities are concerned with improving the design of safety-critical systems. This work discusses a modeling effort that leveraged methods from both fields to perform formal verification of human–automation interaction with a programmable device. This effort utilizes a system architecture composed of independent models of the human mission, human task behavior, human-device interface, device automation, and operational environment. The goals of this architecture were to allow HFE practitioners to perform formal verifications of realistic systems that depend on human–automation interaction in a reasonable amount of time using representative models, intuitive modeling constructs, and decoupled models of system components that could be easily changed to support multiple analyses. This framework was instantiated using a patient controlled analgesia pump in a two phased process where models in each phase were verified using a common set of specifications. The first phase focused on the mission, human-device interface, and device automation; and included a simple, unconstrained human task behavior model. The second phase replaced the unconstrained task model with one representing normative pump programming behavior. Because models produced in the first phase were too large for the model checker to verify, a number of model revisions were undertaken that affected the goals of the effort. While the use of human task behavior models in the second phase helped mitigate model complexity, verification time increased. Additional modeling tools and technological developments are necessary for model checking to become a more usable technique for HFE. PMID:21572930

Bass, Ellen J.

2011-01-01

136

Lesion studies of human emotion and feeling.  

PubMed

The lesion method provides unique insight into how the human brain generates emotion and feeling. Recent work has explored a number of interesting topics including the dissociation of emotional experience from memory in patients with amnesia, the reliability of specific emotional deficits following focal brain damage (including fear and the amygdala), and the investigation of compensatory neural mechanisms in lesion patients. Several detailed case studies have challenged the necessary role of the insular cortex in both awareness and feeling by showing that even in rare instances of complete bilateral insula destruction, the patient remains fully sentient and capable of expressing and feeling emotion. These findings highlight the distributed nature of emotion processing in the human brain and emphasize the importance of utilizing the lesion method for elucidating brain-behavior relationships. PMID:23294552

Feinstein, Justin S

2013-06-01

137

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

138

Tea and Health: Studies in Humans  

PubMed Central

Tea, next to water is the cheapest beverage humans consume. Drinking the beverage tea has been considered a health-promoting habit since ancient times. The modern medicinal research is providing a scientific basis for this belief. The evidence supporting the health benefits of tea drinking grows stronger with each new study that is published in the scientific literature. Tea plant Camellia sinensis has been cultivated for thousands of years and its leaves have been used for medicinal purposes. Tea is used as a popular beverage worldwide and its ingredients are now finding medicinal benefits. Encouraging data showing cancer-preventive effects of green tea from cell-culture, animal and human studies have emerged. Evidence is accumulating that black tea may have similar beneficial effects. Tea consumption has also been shown to be useful for prevention of many debilitating human diseases that include maintenance of cardiovascular and metabolic health. Various studies suggest that polyphenolic compounds present in green and black tea are associated with beneficial effects in prevention of cardiovascular diseases, particularly of atherosclerosis and coronary heart disease. In addition, anti-aging, antidiabetic and many other health beneficial effects associated with tea consumption are described. Evidence is accumulating that catechins and theaflavins, which are the main polyphenolic compounds of green and black tea, respectively, are responsible for most of the physiological effects of tea. This article describes the evidences from clinical and epidemiological studies in the prevention of chronic diseases like cancer and cardiovascular diseases and general health promotion associated with tea consumption. PMID:23448443

Khan, Naghma; Mukhtar, Hasan

2014-01-01

139

study abroad STUDY ABROADFOR HUMAN DEVELOPMENT AND FAMILY SCIENCES MAJORS  

E-print Network

offerings. Visit the "My Credit Abroad" database online to view direct course matches. EXPERIENTIAL LEARNING Development and Family Sciences, College of Natural Sciences PRE-HEALTH PROFESSIONS OPTIONS Explore the "Study. #12;QUESTIONS � Visit the Human Ecology Advising Center online: http

John, Lizy Kurian

140

Bioavailability of tocotrienols: evidence in human studies  

PubMed Central

As a minor component of vitamin E, tocotrienols were evident in exhibiting biological activities such as neuroprotection, radio-protection, anti-cancer, anti-inflammatory and lipid lowering properties which are not shared by tocopherols. However, available data on the therapeutic window of tocotrienols remains controversial. It is important to understand the absorption and bioavailability mechanisms before conducting in-depth investigations into the therapeutic efficacy of tocotrienols in humans. In this review, we updated current evidence on the bioavailability of tocotrienols from human studies. Available data from five studies suggested that tocotrienols may reach its target destination through an alternative pathway despite its low affinity for ?-tocopherol transfer protein. This was evident when studies reported considerable amount of tocotrienols detected in HDL particles and adipose tissues after oral consumption. Besides, plasma concentrations of tocotrienols were shown to be higher when administered with food while self-emulsifying preparation of tocotrienols was shown to enhance the absorption of tocotrienols. Nevertheless, mixed results were observed based on the outcome from 24 clinical studies, focusing on the dosages, study populations and formulations used. This may be due to the variation of compositions and dosages of tocotrienols used, suggesting a need to understand the formulation of tocotrienols in the study design. Essentially, implementation of a control diet such as AHA Step 1 diet may influence the study outcomes, especially in hypercholesterolemic subjects when lipid profile might be modified due to synergistic interaction between tocotrienols and control diet. We also found that the bioavailability of tocotrienols were inconsistent in different target populations, from healthy subjects to smokers and diseased patients. In this review, the effect of dosage, composition and formulation of tocotrienols as well as study populations on the bioavailability of tocotrienols will be discussed. PMID:24410975

2014-01-01

141

Bioavailability of tocotrienols: evidence in human studies.  

PubMed

As a minor component of vitamin E, tocotrienols were evident in exhibiting biological activities such as neuroprotection, radio-protection, anti-cancer, anti-inflammatory and lipid lowering properties which are not shared by tocopherols. However, available data on the therapeutic window of tocotrienols remains controversial. It is important to understand the absorption and bioavailability mechanisms before conducting in-depth investigations into the therapeutic efficacy of tocotrienols in humans. In this review, we updated current evidence on the bioavailability of tocotrienols from human studies. Available data from five studies suggested that tocotrienols may reach its target destination through an alternative pathway despite its low affinity for ?-tocopherol transfer protein. This was evident when studies reported considerable amount of tocotrienols detected in HDL particles and adipose tissues after oral consumption. Besides, plasma concentrations of tocotrienols were shown to be higher when administered with food while self-emulsifying preparation of tocotrienols was shown to enhance the absorption of tocotrienols. Nevertheless, mixed results were observed based on the outcome from 24 clinical studies, focusing on the dosages, study populations and formulations used. This may be due to the variation of compositions and dosages of tocotrienols used, suggesting a need to understand the formulation of tocotrienols in the study design. Essentially, implementation of a control diet such as AHA Step 1 diet may influence the study outcomes, especially in hypercholesterolemic subjects when lipid profile might be modified due to synergistic interaction between tocotrienols and control diet. We also found that the bioavailability of tocotrienols were inconsistent in different target populations, from healthy subjects to smokers and diseased patients. In this review, the effect of dosage, composition and formulation of tocotrienols as well as study populations on the bioavailability of tocotrienols will be discussed. PMID:24410975

Fu, Ju-Yen; Che, Hui-Ling; Tan, Doryn Meam-Yee; Teng, Kim-Tiu

2014-01-01

142

Roadmap: Physical Education Human Movement Studies Bachelor of Science  

E-print Network

] ATTR 25057 Human Anatomy and Physiology I or EXSC 25057 Human Anatomy and Physiology I 3 PEP 25033Roadmap: Physical Education ­ Human Movement Studies ­ Bachelor of Science [EH-BS-PEP-HMS] College of Education, Health and Human Services School of Teaching, Learning and Curriculum Studies Catalog Year: 2012

Sheridan, Scott

143

Limited Spillover to Humans from West Nile Virus Viremic Birds in Atlanta, Georgia  

PubMed Central

Abstract West Nile Virus (WNV) is a mosquito-borne pathogen that impacts the health of its passerine bird hosts as well as incidentally infected humans in the United States. Intensive enzootic activity among the hosts and vectors does not always lead to human outbreaks, as is the situation throughout much of the southeastern United States. In Georgia, substantial yearly evidence of WNV in the mosquito vectors and avian hosts since 2001 has only led to 324 human cases. Although virus has been consistently isolated from mosquitoes trapped in Atlanta, GA, little is known about viral activity among the passerine hosts. A possible reason for the suppression of WNV spillover to humans is that viremic birds are absent from high human-use areas of the city. To test this hypothesis, multiseason, multihabitat, longitudinal WNV surveillance for active WNV viremia was conducted within the avian host community of urban Atlanta by collection of blood samples from wild passerine birds in five urban microhabitats. WNV was isolated from the serum of six blood samples collected from 630 (0.95%) wild passerine birds in Atlanta during 2010–2012, a proportion similar to that found in the Chicago, IL, area in 2005, when over 200 human cases were reported. Most of the viremic birds were Northern Cardinals, suggesting they may be of particular importance to the WNV transmission cycle in Georgia. Results indicated active WNV transmission in all microhabitats of urban Atlanta, except in the old-growth forest patches. The number of viremic birds was highest in Zoo Atlanta, where 3.5% of samples were viremic. Although not significant, these observations may suggest a possible transmission reduction effect of urban old-growth forests and a potential role in WNV amplification for Zoo Atlanta. Overall, spillover to humans remains a rare occurrence in urban Atlanta settings despite active WNV transmission in the avian population. PMID:24107200

Mead, Daniel G.; Kitron, Uriel D.

2013-01-01

144

Sex Without Friction: the Limits of Multi-Mediated Human Subjectivity in Cheang Shu Lea's Tech-Porn  

Microsoft Academic Search

Sex Without Friction focuses on Cheang Shu Lea's science fiction porno I.K.U. (2000) as provocation to think through the limitations of social and cultural criticism that is premised on mediation. Directed by Taiwan-born digital nomad Cheang, multimedia film I.K.U. features a gender-morphing human clone, programmed to collect sexual experiences for the future mass production of sex simulation pills. I.K.U. positions

Jian Chen

2010-01-01

145

Sex Without Friction: the Limits of Multi-Mediated Human Subjectivity in Cheang Shu Lea's Tech-Porn  

Microsoft Academic Search

:Sex Without Friction focuses on Cheang Shu Lea's science fiction porno I.K.U. (2000) as provocation to think through the limitations of social and cultural criticism that is premised on mediation. Directed by Taiwan-born digital nomad Cheang, multimedia film I.K.U. features a gender-morphing human clone, programmed to collect sexual experiences for the future mass production of sex simulation pills. I.K.U. positions

Jian Chen

2010-01-01

146

Preliminary neutron crystallographic study of human transthyretin  

PubMed Central

Preliminary studies of perdeuterated crystals of human transthyretin (TTR) have been carried out using the LADI-III and D19 diffractometers at the Institut Laue–Langevin in Grenoble. The results demonstrate the feasibility of a full crystallographic analysis to a resolution of 2.0?Å using Laue diffraction and also illustrate the potential of using monochromatic instruments such as D19 for higher resolution studies where larger crystals having smaller unit cells are available. This study will yield important information on hydrogen bonding, amino-acid protonation states and hydration in the protein. Such information will be of general interest for an understanding of the factors that stabilize/destabilize TTR and for the design of ligands that may be used to counter TTR amyloid fibrillogenesis. PMID:22102249

Haupt, Melina; Blakeley, Matthew P.; Teixeira, Susana C. M.; Mason, Sax A.; Mitchell, Edward P.; Cooper, Jonathan B.; Forsyth, V. Trevor

2011-01-01

147

A pair of roseate terns fledges three young with limited human assistance  

USGS Publications Warehouse

In 1994 when the availability of small fish appeared to be relatively good, the smallest chick from an inadvertantly artificially-created 3-egg clutch received occasional supplemental feedings by humans for two weeks. These supplemental feedings probably prevented this chick from starving. During its period of most rapid growth (after the linear growth phase of its two siblings had ended), however, it did not receive supplemental feedings from humans, but was instead was fed only by the two adult birds attending the nest. All the chicks in this brood eventually fledged, indicating that the pair was capable of meeting the feeding demands of three large chicks.

Spendelow, J.A.; Zingo, J.M.; Foss, S.

1997-01-01

148

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 and…

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

2012-01-01

149

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

PubMed Central

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 inter-correlations in brain region volumes, distinct allometric scaling for each brain region and the relative independence in olfactory and limbic structures 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, hippocampus) by using magnetic resonance imaging scans of 90 human brains ranging between 16 to 25 years of age. Human brain variation resembles both the individual variation seen in other species, and variation observed across mammalian species. That is, 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 non-random pattern of variation suggests that developmental programs channel the variation available for selection. PMID:23363667

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

2013-01-01

150

Limits of Capacity for the Exchange of Information in the Human Nervous System  

Microsoft Academic Search

An approximation to the maximum capacity of exchange of information in the central nervous system of the human body is carried out. The maximum possible quantity in bits per second that the brain possibly exchanges with the rest of the body is sought for. This value could be useful for the designing of bionic systems, the analysis of the operation

Elkin Echeverri

2006-01-01

151

SAFETY, IDENTITY AND CONSENT: A LIMITED DEFENSE OF REPRODUCTIVE HUMAN CLONING  

Microsoft Academic Search

ABSTRACTSome 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

2006-01-01

152

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. PMID:20703439

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

2010-01-01

153

Metabolic Phenotyping Guidelines: studying eating behaviour in humans.  

PubMed

The study of human appetite and eating behaviour has become increasingly important in recent years due to the rise in body weight dysregulation through both obesity and eating disorders. Adequate control over appetite is paramount for the control of body weight and in order to understand appetite, it is necessary to measure eating behaviour accurately. So far, research in this field has revealed that no single experimental design can answer all research questions. Each research question posed will require a specific study design that will limit the findings of that study to those particular conditions. For example, choices will be made among the use of laboratory or free-living studies, time period for examination, specific measurement techniques and investigative methodologies employed. It is important that these represent informed decisions about what design and which methodology will provide the most meaningful outcomes. This review will examine some of the 'gold standard' study designs and methodologies currently employed in the study of human appetite and eating behaviour. PMID:25052364

Gibbons, Catherine; Finlayson, Graham; Dalton, Michelle; Caudwell, Phillipa; Blundell, John E

2014-08-01

154

Ethical Issues Arising from the Study of the Human Genome  

NSDL National Science Digital Library

The characterization of the human genome through the mapping and sequencing of human DNA is giving us new insight into our genetic heritage. This new genetic knowledge may also enable us to modify the human genome in order to treat disease or enhance or delete certain human traits. A number of ethical issues raised by our increased understanding of the human genome and the application of new genetic technologies are addressed. What limits, if any, should we set to our growing genetic knowledge and technology? The keynote speaker of this seminar is Dr Francis Collins .This resource also includes a summary of this lecture by James Miller.

Francis Collins (;)

2007-06-27

155

MONOAMINE OXIDASE: RADIOTRACER DEVELOPMENT AND HUMAN STUDIES.  

SciTech Connect

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 the metabolism of drugs and xenobiotics is gaining attention (Strolin Benedetti and Tipton, 1998; Castagnoli et al., 1997.). MAO is well suited for this role because its concentration in organs such as kidneys, liver and digestive organs is high sometimes exceeding that in the brain. Knowledge of the distribution of the MAO subtypes within different organs and different cells is important in determining which substrates (and which drugs and xenobiotics) have access to which MAO subtypes. The highly variable subtype distribution with different species makes human studies even more important. In addition, the deleterious side effects of combining MAO inhibitors with other drugs and with foodstuffs makes it important to know the MAO inhibitory potency of different drugs both in the brain and in peripheral organs (Ulus et al., 2000). Clearly PET can play a role in answering these questions, in drug research and development and in discovering some of the factors which contribute to the highly variable MAO levels in different individuals.

FOWLER,J.S.; LOGAN,J.; VOLKOW,N.D.; WANG,G.J.; MACGREGOR,R.R.; DING,Y.S.

2000-09-28

156

Vision of Space Exploration Possibilities and limits of a human space conquest.  

NASA Astrophysics Data System (ADS)

Few generations of a schoolboys, which later become active and productive space researchers, have been brought up on a science fiction books. These books told us about travels to other Galaxies with velocities larger then velocity of light, meetings with friendly aliens (necessarily with communistic mentalities in Soviet Union books), star wars with ugly space monsters (in the western hemisphere books), etc. Beginning of Space age (4/10/1957) opened the door to a magic box, full of scientific discoveries, made mostly by robotic satellites and spacecraft. However, already the first human space trips clearly demonstrated that space is vigorously hostile to a human beings. Space medicine during the years since Gagarin flight, made an outstanding progress in supporting human presence at orbital stations, but the radiation hazards and problem of hypomagnetism are still opened and there is no visible path to their solution. So the optimistic slogan of 60-ies “Space is Our Place” is not supported by an almost half a century practice. Space never will be a comfortable place for soft and vulnerable humans? There is a general consensus that man will be on Mars during this century (or even its first part). This is very difficult but task it seems to be realistic after the significant advance of modern technologies will be made. But, is there any real need for humans to travel beyond the Mars orbit or to the inner regions of the Solar system? Will the age of Solar system exploration comes to its logical as it was described by Stanislav Lem in his famous book “Return from stars”? The author of this talk has more questions than answers, and thinks that PEX1 Panel on Exploration is just a right place to discuss these usually by passed topics.

Zelenyi, Lev

157

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. PMID:20522007

Hirth, Frank

2010-01-01

158

Transgenic Rabbit Models for Studying Human Cardiovascular Diseases  

PubMed Central

Cardiovascular diseases involve the heart or blood vessels and remain a leading cause of morbidity and mortality in developed countries. A variety of animal models have been used to study cardiovascular diseases and have contributed to our understanding of their pathophysiology and treatment. However, mutations or abnormal expression of specific genes play important roles in the pathophysiology of some heart diseases, for which a closely similar animal model often is not naturally available. With the advent of techniques for specific genomic modification, several transgenic and knockout mouse models have been developed for cardiovascular conditions that result from spontaneous mutations. However, mouse and human heart show marked electrophysiologic differences. In addition, cardiac studies in mouse models are extremely difficult because of their small heart size and fast heart rate. Therefore, larger genetically engineered animal models are needed to overcome the limitations of the mouse models. This review summarizes the transgenic rabbit models that have been developed to study cardiovascular diseases. PMID:23561880

2012-01-01

159

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

160

The Limitations of “Vulnerability” as a Protection for Human Research Participants  

Microsoft Academic Search

Vulnerability is one of the least examined concepts in research ethics. Vulnerability was linked in the Belmont Report to questions of justice in the selection of subjects. Regulations and policy documents regarding the ethical conduct of research have focused on vulnerability in terms of limitations of the capacity to provide informed consent. Other interpretations of vulnerability have emphasized unequal power

Carol Levine; Ruth Faden; Christine Grady; Dale Hammerschmidt; Lisa Eckenwiler; Jeremy Sugarman

2004-01-01

161

A Numerical Study of the Semi-classical Limit of the Focusing Nonlinear Schrodinger Equation  

E-print Network

. Examples, both integrable and nonintegrable, are ample: the KdV equation [9, 22], the general- ized KdVA Numerical Study of the Semi-classical Limit of the Focusing Nonlinear Schrodinger Equation@math.ohio-state.edu Abstract We study the solution of the focusing nonlinear Schrodinger equation in the semi- classical limit

Bigelow, Stephen

162

Human Development Impacts of Migration: South Africa Case Study  

Microsoft Academic Search

Controls on human mobility and efforts to undermine them continue to shape South Africa’s politics, economy, and society. Despite the need for improved policy responses to human mobility, reform is hindered by lack of capacity, misinformation, and anti-migrant sentiments within and outside of government. This report outlines these trends and tensions by providing a broad overview of the limited demographic

Loren B. Landau; Aurelia Wa Kabwe-Segatti

2009-01-01

163

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

164

All That Glitters Isn't Gold: A Survey on Acknowledgment of Limitations in Biomedical Studies  

PubMed Central

Background Acknowledgment of all serious limitations to research evidence is important for patient care and scientific progress. Formal research on how biomedical authors acknowledge limitations is scarce. Objectives To assess the extent to which limitations are acknowledged in biomedical publications explicitly, and implicitly by investigating the use of phrases that express uncertainty, so-called hedges; to assess the association between industry support and the extent of hedging. Design We analyzed reporting of limitations and use of hedges in 300 biomedical publications published in 30 high and medium -ranked journals in 2007. Hedges were assessed using linguistic software that assigned weights between 1 and 5 to each expression of uncertainty. Results Twenty-seven percent of publications (81/300) did not mention any limitations, while 73% acknowledged a median of 3 (range 1–8) limitations. Five percent mentioned a limitation in the abstract. After controlling for confounders, publications on industry-supported studies used significantly fewer hedges than publications not so supported (p?=?0.028). Limitations Detection and classification of limitations was – to some extent – subjective. The weighting scheme used by the hedging detection software has subjective elements. Conclusions Reporting of limitations in biomedical publications is probably very incomplete. Transparent reporting of limitations may protect clinicians and guideline committees against overly confident beliefs and decisions and support scientific progress through better design, conduct or analysis of new studies. PMID:24324540

ter Riet, Gerben; Chesley, Paula; Gross, Alan G.; Siebeling, Lara; Muggensturm, Patrick; Heller, Nadine; Umbehr, Martin; Vollenweider, Daniela; Yu, Tsung; Akl, Elie A.; Brewster, Lizzy; Dekkers, Olaf M.; Muhlhauser, Ingrid; Richter, Bernd; Singh, Sonal; Goodman, Steven; Puhan, Milo A.

2013-01-01

165

An immunohistological study of human lymphoma.  

PubMed Central

In this study the problems encountered in staining immunoglobulin (Ig) in sections of paraffin-embedded human lymphoma samples have been investigated. It was found that the "masking' of cytoplasmic Ig, which occurs when tissues are fixed in formol saline (the fixative employed in most previous studies), can be avoided by the use of mercury-based fixatives. When non-Hodgkin's lymphoma samples fixed in this way were studied it was found that cytoplasmic Ig labelling of both lymphoid and histiocytic cells is often attributable to non-specific uptake of serum proteins. This phenomenon probably accounts for a number of published anomalous immunoperoxidase staining results in human lymphoma (e.g. the presence of both kappa and lambda chains in the same neoplastic cell). Double immunoenzymatic labelling (using alkaline phosphatase and peroxidase) proved valuable in the elucidation of this phenomenon. When staining due to absorbed Ig was discounted it was possible to demonstrate monoclonal Ig labelling in seven out of sixteen cases of non-Hodgkin's lymphoma. In each case IgM was found in association with a single light chain type and these results were in agreement with those obtained by direct immunofluorescent labelling of cryostat sections. In a further case u chains without associated light chains were demonstrated by immunoperoxidase staining. Seven cases of Hodgkin's disease were studied by immunoenzymatic techniques. Although IgG was frequently found in Reed-Sternberg and Hodgkin's cells its presence was not attributable to non-specific uptake of serum protein since albumin was absent or only present in small amounts. These findings are in support of the macrophage origin of these cells. Images Fig. 1 Fig. 2 Fig. 4 Fig. 5 Fig. 8 Fig. 9 Fig. 3 Fig. 6 Fig. 7 PMID:7002385

Mason, D Y; Bell, J I; Christensson, B; Biberfeld, P

1980-01-01

166

Evaluation of streams in selected communities for the application of limited-detail study methods for flood-insurance studies  

USGS Publications Warehouse

The U.S. Geological Survey evaluated 2,349 communities in 1984 for the application of limited-detail flood-insurance study methods, that is, methods with a reduced effort and cost compared to the detailed studies. Limited-detail study methods were found to be appropriate for 1,705 communities, while detailed studies were appropriate for 62 communities and no studies were appropriate for 582 communities. The total length of streams for which limited-detail studies are recommended is 9 ,327 miles with a corresponding cost of $23,007,000. This results in average estimated costs for conducting limited-detail studies of $2,500 per mile of studied stream length. The purpose of the report is to document the limited-detail study methods and the results of the evaluation. (USGS)

Cobb, Ernest D.

1986-01-01

167

Human interaural time difference thresholds for sine tones: The high-frequency limit  

PubMed Central

The smallest detectable interaural time difference (ITD) for sine tones was measured for four human listeners to determine the dependence on tone frequency. At low frequencies, 250–700 Hz, threshold ITDs were approximately inversely proportional to tone frequency. At mid-frequencies, 700–1000 Hz, threshold ITDs were smallest. At high frequencies, above 1000 Hz, thresholds increased faster than exponentially with increasing frequency becoming unmeasurably high just above 1400?Hz. A model for ITD detection began with a biophysically based computational model for a medial superior olive (MSO) neuron that produced robust ITD responses up to 1000?Hz, and demonstrated a dramatic reduction in ITD-dependence from 1000 to 1500?Hz. Rate-ITD functions from the MSO model became inputs to binaural display models—both place based and rate-difference based. A place-based, centroid model with a rigid internal threshold reproduced almost all features of the human data. A signal-detection version of this model reproduced the high-frequency divergence but badly underestimated low-frequency thresholds. A rate-difference model incorporating fast contralateral inhibition reproduced the major features of the human threshold data except for the divergence. A combined, hybrid model could reproduce all the threshold data. PMID:23654390

Brughera, Andrew; Dunai, Larisa; Hartmann, William M.

2013-01-01

168

Spatial Genetic Structure Patterns of Phenotype-Limited and Boundary-Limited Expanding Populations: A Simulation Study  

PubMed Central

Range expansions may create a unique spatial genetic pattern characterized by alternate genetically homogeneous domains and allele frequency clines. Previous attempts to model range expansions have mainly focused on the loss of genetic diversity during expansions. Using individual-based models, we examined spatial genetic patterns under two expansion scenarios, boundary-limited range expansions (BLRE) and phenotype-limited range expansions (PhLRE). Our simulation revealed that the genetic diversity within populations lost quickly during the range expansion, while the genetic difference accumulated between populations. Consequently, accompanying the expansions, the overall diversity featured a slow decrease. Specifically, during BLREs, high speed of boundary motion facilitated the maintenance of total genetic diversity and sharpened genetic clines. Very slight constraints on boundary motion of BLREs drastically narrowed the homogeneous domains and increased the allele frequency fluctuations from those levels exhibited by PhLREs. Even stronger constraints, however, surprisingly brought the width of homogeneous domains and the allele frequency fluctuations back to the normal levels of PhLREs. Furthermore, high migration rates maintained a higher total genetic diversity than low ones did during PhLREs. Whereas, the total genetic diversities during BLREs showed a contrary pattern: higher when migration was low than those when migration was high. Besides, the increase of migration rates helped maintain a greater number of homogeneous domains during PhLREs, but their effects on the number of homogeneous domains during BLREs were not monotonous. Previous studies have showed that the homogenous domains can merge to form a few broad domains as the expansion went on, leading to fewer homogeneous domains. Our simulations, meanwhile, revealed that the range expansions could also rebuild homogeneous domains from the clines during the range expansion. It is possible that that the number of homogeneous domains was determined by the interaction of merging and newly emerging homogeneous domains. PMID:24465700

Dai, Qiang; Zhan, Xiangjiang; Lu, Bin; Fu, Jinzhong; Wang, Qian; Qi, Dunwu

2014-01-01

169

Spatial genetic structure patterns of phenotype-limited and boundary-limited expanding populations: a simulation study.  

PubMed

Range expansions may create a unique spatial genetic pattern characterized by alternate genetically homogeneous domains and allele frequency clines. Previous attempts to model range expansions have mainly focused on the loss of genetic diversity during expansions. Using individual-based models, we examined spatial genetic patterns under two expansion scenarios, boundary-limited range expansions (BLRE) and phenotype-limited range expansions (PhLRE). Our simulation revealed that the genetic diversity within populations lost quickly during the range expansion, while the genetic difference accumulated between populations. Consequently, accompanying the expansions, the overall diversity featured a slow decrease. Specifically, during BLREs, high speed of boundary motion facilitated the maintenance of total genetic diversity and sharpened genetic clines. Very slight constraints on boundary motion of BLREs drastically narrowed the homogeneous domains and increased the allele frequency fluctuations from those levels exhibited by PhLREs. Even stronger constraints, however, surprisingly brought the width of homogeneous domains and the allele frequency fluctuations back to the normal levels of PhLREs. Furthermore, high migration rates maintained a higher total genetic diversity than low ones did during PhLREs. Whereas, the total genetic diversities during BLREs showed a contrary pattern: higher when migration was low than those when migration was high. Besides, the increase of migration rates helped maintain a greater number of homogeneous domains during PhLREs, but their effects on the number of homogeneous domains during BLREs were not monotonous. Previous studies have showed that the homogenous domains can merge to form a few broad domains as the expansion went on, leading to fewer homogeneous domains. Our simulations, meanwhile, revealed that the range expansions could also rebuild homogeneous domains from the clines during the range expansion. It is possible that that the number of homogeneous domains was determined by the interaction of merging and newly emerging homogeneous domains. PMID:24465700

Dai, Qiang; Zhan, Xiangjiang; Lu, Bin; Fu, Jinzhong; Wang, Qian; Qi, Dunwu

2014-01-01

170

A Human Study of Fault Localization Accuracy Zachary P. Fry  

E-print Network

A Human Study of Fault Localization Accuracy Zachary P. Fry University of Virginia Email: zpf5a to debug, however. We present formal models, backed by a human study involving 65 participants (from both to human accuracy at locating errors. Our study involves example code from Java textbooks, helping us

Weimer, Westley

171

Monitoring Antiretroviral Therapy in Resource-Limited Settings: Balancing Clinical Care, Technology, and Human Resources  

Microsoft Academic Search

Due to the rapid expansion of first-line antiretroviral therapy in resource-limited settings (RLS), increasing numbers of\\u000a people are living with HIV for prolonged periods of time. Treatment programs must now decide how to balance monitoring costs\\u000a necessary to maximize health benefits for those already on treatment with the continued demand to initiate more patients on\\u000a first-line treatment. We review currently

Mina C. Hosseinipour; Mauro Schechter

2010-01-01

172

Generation of a suite of 3D computer-generated breast phantoms from a limited set of human subject data  

SciTech Connect

Purpose: The authors previously reported on a three-dimensional computer-generated breast phantom, based on empirical human image data, including a realistic finite-element based compression model that was capable of simulating multimodality imaging data. The computerized breast phantoms are a hybrid of two phantom generation techniques, combining empirical breast CT (bCT) data with flexible computer graphics techniques. However, to date, these phantoms have been based on single human subjects. In this paper, the authors report on a new method to generate multiple phantoms, simulating additional subjects from the limited set of original dedicated breast CT data. The authors developed an image morphing technique to construct new phantoms by gradually transitioning between two human subject datasets, with the potential to generate hundreds of additional pseudoindependent phantoms from the limited bCT cases. The authors conducted a preliminary subjective assessment with a limited number of observers (n= 4) to illustrate how realistic the simulated images generated with the pseudoindependent phantoms appeared. Methods: Several mesh-based geometric transformations were developed to generate distorted breast datasets from the original human subject data. Segmented bCT data from two different human subjects were used as the 'base' and 'target' for morphing. Several combinations of transformations were applied to morph between the 'base' and 'target' datasets such as changing the breast shape, rotating the glandular data, and changing the distribution of the glandular tissue. Following the morphing, regions of skin and fat were assigned to the morphed dataset in order to appropriately assign mechanical properties during the compression simulation. The resulting morphed breast was compressed using a finite element algorithm and simulated mammograms were generated using techniques described previously. Sixty-two simulated mammograms, generated from morphing three human subject datasets, were used in a preliminary observer evaluation where four board certified breast radiologists with varying amounts of experience ranked the level of realism (from 1 ='fake' to 10 ='real') of the simulated images. Results: The morphing technique was able to successfully generate new and unique morphed datasets from the original human subject data. The radiologists evaluated the realism of simulated mammograms generated from the morphed and unmorphed human subject datasets and scored the realism with an average ranking of 5.87 {+-} 1.99, confirming that overall the phantom image datasets appeared more 'real' than 'fake.' Moreover, there was not a significant difference (p > 0.1) between the realism of the unmorphed datasets (6.0 {+-} 1.95) compared to the morphed datasets (5.86 {+-} 1.99). Three of the four observers had overall average rankings of 6.89 {+-} 0.89, 6.9 {+-} 1.24, 6.76 {+-} 1.22, whereas the fourth observer ranked them noticeably lower at 2.94 {+-} 0.7. Conclusions: This work presents a technique that can be used to generate a suite of realistic computerized breast phantoms from a limited number of human subjects. This suite of flexible breast phantoms can be used for multimodality imaging research to provide a known truth while concurrently producing realistic simulated imaging data.

Hsu, Christina M. L. [Department of Biomedical Engineering, Duke University, Durham, North Carolina 27708 and Carl E. Ravin Advanced Imaging Laboratories, Duke University Medical Center, Durham, North Carolina 27705 (United States); Palmeri, Mark L. [Department of Biomedical Engineering, Duke University, Durham, North Carolina 27708 (United States); Department of Anesthesiology, Duke University Medical Center, Durham, North Carolina 27710 (United States); Segars, W. Paul [Carl E. Ravin Advanced Imaging Laboratories, Duke University Medical Center, Durham, North Carolina 27705 (United States); Department of Radiology, Duke University Medical Center, Durham, North Carolina 27710 (United States); Department of Biomedical Engineering, Duke University, Durham, North Carolina 27708 (United States); Medical Physics Graduate Program, Duke University, Durham, North Carolina 27705 (United States); Veress, Alexander I. [Department of Mechanical Engineering, University of Washington, Seattle, Washington 98195 (United States); Dobbins, James T. III [Carl E. Ravin Advanced Imaging Laboratories, Duke University Medical Center, Durham, North Carolina 27705 (United States); Department of Radiology, Duke University Medical Center, Durham, North Carolina 27710 (United States); Department of Biomedical Engineering, Duke University, Durham, North Carolina 27708 (United States); Medical Physics Graduate Program, Duke University, Durham, North Carolina 27705 (United States); Department of Physics, Duke University, Durham, North Carolina 27708 (United States)

2013-04-15

173

The importance of human performance and procedures in limiting severe accident risks  

SciTech Connect

Due to the defense in depth concept and redundancy in safety systems utilized, complex industrial plants, such as nuclear power plants (NPPs) can be operated safely. This capability has been demonstrated by many years of safe operation by numerous NPPs in the US and abroad. However, the occurrence of severe accidents has also demonstrated that constant vigilance in a number of areas is necessary to ensure continued safe operation. The areas noted as particularly important are Design, Organization and Management, Maintenance, and Operations (Human Performance). 18 refs.

Higgins, J.C.

1990-01-01

174

On the limits of enhancement in human gene transfer: drawing the line.  

PubMed

Enhancement-line human genetic engineering has recurrently been targeted for bioethical discussion and is usually (if not always) illustrated by examples alluding to a genetic technology that is far beyond our current possibilities. By discussing an ambitious project related to solid tumor cancers--multidrug resistance (MDR)--the present paper places the question on a more realistic plane and draws bioethical conclusions to serve as guidelines in the field. The paper also establishes the inadequacy of the prevalent concept of genetic medicine as one of substitution. PMID:9095461

Torres, J M

1997-02-01

175

A Critical Review of Biomarkers Used for Monitoring Human Exposure to Lead: Advantages, Limitations, and Future Needs  

PubMed Central

Lead concentration in whole blood (BPb) is the primary biomarker used to monitor exposure to this metallic element. The U.S. Centers for Disease Control and Prevention and the World Health Organization define a BPb of 10 ?g/dL (0.48 ?mol/L) as the threshold of concern in young children. However, recent studies have reported the possibility of adverse health effects, including intellectual impairment in young children, at BPb levels < 10 ?g/dL, suggesting that there is no safe level of exposure. It appears impossible to differentiate between low-level chronic Pb exposure and a high-level short Pb exposure based on a single BPb measurement; therefore, serial BPb measurements offer a better estimation of possible health outcomes. The difficulty in assessing the exact nature of Pb exposure is dependent not so much on problems with current analytical methodologies, but rather on the complex toxicokinetics of Pb within various body compartments (i.e., cycling of Pb between bone, blood, and soft tissues). If we are to differentiate more effectively between Pb stored in the body for years and Pb from recent exposure, information on other biomarkers of exposure may be needed. None of the current biomarkers of internal Pb dose have yet been accepted by the scientific community as a reliable substitute for a BPb measurement. This review focuses on the limitations of biomarkers of Pb exposure and the need to improve the accuracy of their measurement. We present here only the traditional analytical protocols in current use, and we attempt to assess the influence of confounding variables on BPb levels. Finally, we discuss the interpretation of BPb data with respect to both external and endogenous Pb exposure, past or recent exposure, as well as the significance of Pb determinations in human specimens including hair, nails, saliva, bone, blood (plasma, whole blood), urine, feces, and exfoliated teeth. PMID:16330345

Barbosa, Fernando; Tanus-Santos, Jose Eduardo; Gerlach, Raquel Fernanda; Parsons, Patrick J.

2005-01-01

176

"Revolting to humanity": oversights, limitations, and complications of the English Legitimacy Act of 1926.  

PubMed

This article analyses three areas that limited the effectiveness of the English Legitimacy Act of 1926. First, re-registration was public, expensive, and time-consuming. Second, the Treasury Office used the change in the law of intestacy to refuse more distant relatives' claims on estates. Third, the law separated legitimacy from nationality, thus denying citizenship to legitimated children born abroad of British fathers and foreign mothers. In short, both because of parliamentary oversights and civil servants' narrow interpretations of the law, relatively few children took advantage of the Act, and the minority who did, rather than being 'illegitimate' or 'legitimate', were a third category, the 'legitimated'. PMID:21299009

Frost, Ginger

2011-01-01

177

O{sub 2}-mediated oxidation of ferrous nitrosylated human serum heme-albumin is limited by nitrogen monoxide dissociation  

SciTech Connect

Research highlights: {yields} Human serum heme-albumin displays globin-like properties. {yields} O{sub 2}-mediated oxidation of ferrous nitrosylated human serum heme-albumin. {yields} Allosteric modulation of human serum heme-albumin reactivity. {yields} Rifampicin is an allosteric effector of human serum heme-albumin. {yields} Human serum heme-albumin is a ROS and NOS scavenger. -- Abstract: Human serum heme-albumin (HSA-heme-Fe) displays globin-like properties. Here, kinetics of O{sub 2}-mediated oxidation of ferrous nitrosylated HSA-heme-Fe (HSA-heme-Fe(II)-NO) is reported. Values of the first-order rate constants for O{sub 2}-mediated oxidation of HSA-heme-Fe(II)-NO (i.e., for ferric HSA-heme-Fe formation) and for NO dissociation from HSA-heme-Fe(II)-NO (i.e., for NO replacement by CO) are k = 9.8 x 10{sup -5} and 8.3 x 10{sup -4} s{sup -1}, and h = 1.3 x 10{sup -4} and 8.5 x 10{sup -4} s{sup -1}, in the absence and presence of rifampicin, respectively, at pH = 7.0 and T = 20.0 {sup o}C. The coincidence of values of k and h indicates that NO dissociation represents the rate limiting step of O{sub 2}-mediated oxidation of HSA-heme-Fe(II)-NO. Mixing HSA-heme-Fe(II)-NO with O{sub 2} does not lead to the formation of the transient adduct(s), but leads to the final ferric HSA-heme-Fe derivative. These results reflect the fast O{sub 2}-mediated oxidation of ferrous HSA-heme-Fe and highlight the role of drugs in modulating allosterically the heme-Fe-atom reactivity.

Ascenzi, Paolo, E-mail: ascenzi@uniroma3.it [Interdepartmental Laboratory of Electron Microscopy, University Roma Tre, Via della Vasca Navale 79, I-00146 Roma (Italy) [Interdepartmental Laboratory of Electron Microscopy, University Roma Tre, Via della Vasca Navale 79, I-00146 Roma (Italy); National Institute for Infectious Diseases I.R.C.C.S. 'Lazzaro Spallanzani', Via Portuense 292, I-00149 Roma (Italy); Gullotta, Francesca; Gioia, Magda; Coletta, Massimo [Department of Experimental Medicine and Biochemical Sciences, University of Roma 'Tor Vergata', Via Montpellier 1, I-00133 Roma (Italy) [Department of Experimental Medicine and Biochemical Sciences, University of Roma 'Tor Vergata', Via Montpellier 1, I-00133 Roma (Italy); Interuniversity Consortium for the Research on the Chemistry of Metals in Biological Systems, Piazza Umberto I 1, I-87100 Bari (Italy); Fasano, Mauro [Department of Structural and Functional Biology, and Center of Neuroscience, University of Insubria, Via Alberto da Giussano 12a, I-21052 Busto Arsizio, VA (Italy)] [Department of Structural and Functional Biology, and Center of Neuroscience, University of Insubria, Via Alberto da Giussano 12a, I-21052 Busto Arsizio, VA (Italy)

2011-03-04

178

Detection of expiratory flow limitation during mechanical ventilation: a simulation study  

Microsoft Academic Search

Expiratory flow limitation (EFL) is frequent in mechanically ventilated patients with obstructive pulmonary disease and its prompt detection is important to optimize respiratory assistance. The present study aims to compare by simulation two methods for the detection of flow limitation in intensive care unit: the negative expiratory pressure (NEP) method and the external resistance (?R) method. To this purpose, a

C. Brighenti; P. Barbini; G. Gnudi

2004-01-01

179

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

180

Approaches to limiting emergence of antimicrobial resistance in bacteria in human populations.  

PubMed

Infectious diseases continue to be major threats to human health around the world. Within the past few years, several divergent groups of organisms have emerged as significant causes of morbidity and mortality. Included among these are bacteria that are refractory to therapy because of the development of resistance to multiple antimicrobial agents. Multidrug resistance in strains of Mycobacterium tuberculosis, Streptococcus pneumoniae, Shigella dysenteriae, Salmonella typhi, and Enterococcus faecium has been reported. Surveillance of resistant microorganisms in the United States and abroad is fragmentary and targets relatively few organisms. Surveillance is further hampered by the fact that detection of some novel resistance mechanisms is difficult by means of current laboratory methods. Both clinicians and public health officials are likely to continue to face a variety of challenges regarding surveillance, treatment, prevention, and control of drug-resistant infections. PMID:8994792

Hughes, J M; Tenover, F C

1997-01-01

181

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. PMID:22457819

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

2012-01-01

182

Accident causation study on roadways with limited sight distance crest vertical curves  

E-print Network

reflect the driver and vehicle population currently on the transportation network. An accident causation study was conducted to determine if roadways with limited stopping sight distance present a safety hazard for the transportation network. Rural two...

Stoddard, Angela May

2012-06-07

183

Autophagy limits the cytotoxic effects of the AKT inhibitor AZ7328 in human bladder cancer cells  

PubMed Central

Background: Mutations that activate the PI3K/AKT/mTOR pathway are relatively common in urothelial (bladder) cancers, but how these pathway mutations affect AKT dependency is not known. We characterized the relationship between AKT pathway mutational status and sensitivity to the effects of the selective AKT kinase inhibitor AZ7328 using a panel of 12 well-characterized human bladder cancer cell lines. Methods: Sequenome DNA sequencing was performed to identify mutations in a panel of 12 urothelial cancer cell lines. Drug-induced proliferative inhibition and apoptosis were quantified using MTT assays and propidium iodide staining with FACS analyses. Protein activation via phosphorylation was measured by immunoblotting. Autophagy was measured by LC3 immunofluorescence and immunoblotting. Results: AZ7328 inhibited proliferation and AKT substrate phosphorylation in a concentration-dependent manner but had minimal effects on apoptosis. Proliferative inhibition correlated loosely with the presence of activating PIK3CA mutations and was strengthened in combination with the mTOR inhibitor rapamycin. AZ7328 induced autophagy in some of the lines, and in the cells exposed to a combination of AZ7328 and chemical autophagy inhibitors apoptosis was induced. Conclusions: The cytostatic effects of AZ7328 correlate with PIK3CA mutations and are greatly enhanced by dual pathway inhibition using an mTOR inhibitor. Furthermore, AZ7328 can interact with autophagy inhibitors to induce apoptosis in some cell lines. Overall, our results support the further evaluation of combinations of PI3K/AKT/mTOR pathway and autophagy inhibitors in pre-clinical in vivo models and ultimately in patients with PIK3CA mutant bladder cancers. PMID:22895070

Dickstein, Rian J.; Nitti, Giovanni; Dinney, Colin P.; Davies, Barry R.; Kamat, Ashish M.; McConkey, David J.

2012-01-01

184

Studying food reward and motivation in humans.  

PubMed

A key challenge in studying reward processing in humans is to go beyond subjective self-report measures and quantify different aspects of reward such as hedonics, motivation, and goal value in more objective ways. This is particularly relevant for the understanding of overeating and obesity as well as their potential treatments. In this paper are described a set of measures of food-related motivation using handgrip force as a motivational measure. These methods can be used to examine changes in food related motivation with metabolic (satiety) and pharmacological manipulations and can be used to evaluate interventions targeted at overeating and obesity. However to understand food-related decision making in the complex food environment it is essential to be able to ascertain the reward goal values that guide the decisions and behavioral choices that people make. These values are hidden but it is possible to ascertain them more objectively using metrics such as the willingness to pay and a method for this is described. Both these sets of methods provide quantitative measures of motivation and goal value that can be compared within and between individuals. PMID:24686284

Ziauddeen, Hisham; Subramaniam, Naresh; Cambridge, Victoria C; Medic, Nenad; Farooqi, Ismaa Sadaf; Fletcher, Paul C

2014-01-01

185

Human Resource Systems in KenyaA Case Study of Hotel Human Resources Performance  

Microsoft Academic Search

A study of 160 managers and employees in four hotels in Nairobi and Mombasa, Kenya, found that functionally flexible human resource systems in conjunction with differentiation strategies are associated with high organizational performance, whereas numerically flexible human resource systems and cost-reduction strategies are linked with low organizational performance. Functionally flexible human resources systems emphasize mutual obligations between management and workers.

Fwaya Erick Onyango; Roselyne N. Okech

2008-01-01

186

Studying the immune response to human viral infections using zebrafish.  

PubMed

Humans and viruses have a long co-evolutionary history. Viral illnesses have and will continue to shape human history: from smallpox, to influenza, to HIV, and beyond. Animal models of human viral illnesses are needed in order to generate safe and effective antiviral medicines, adjuvant therapies, and vaccines. These animal models must support the replication of human viruses, recapitulate aspects of human viral illnesses, and respond with conserved immune signaling cascades. The zebrafish is perhaps the simplest, most commonly used laboratory model organism in which innate and/or adaptive immunity can be studied. Herein, we will discuss the current zebrafish models of human viral illnesses and the insights they have provided. We will highlight advantages of early life stage zebrafish and the importance of innate immunity in human viral illnesses. We will also discuss viral characteristics to consider before infecting zebrafish with human viruses as well as predict other human viruses that may be able to infect zebrafish. PMID:24718256

Goody, Michelle F; Sullivan, Con; Kim, Carol H

2014-09-01

187

Studies of human breast cancer metastasis using nude mice  

Microsoft Academic Search

Athymic nude mice have been used in recent years to study the biology of human tumors and to assess therapeutic responses in vivo rather than just in vitro. Some human tumors metastasize in nude mice, providing model systems for analyzing various aspects of the metastatic phenotype of human neoplasms. For breast carcinomas, however, the tumor-take rate of surgical specimens is

Janet E. Price; Ruo Dan Zhang

1990-01-01

188

Human Motion in Cooperative Tasks: Moving Object Case Study  

E-print Network

Human Motion in Cooperative Tasks: Moving Object Case Study Sylvain Miossec AIST/CNRS JRL Email, for a pair of human operators, in moving a handle-shaped object between two predefined locations on a table of human haptics in physical cooperative tasks involving an object intermediary, which we term person

Paris-Sud XI, Université de

189

Studying Risk Factors Associated with Human Leptospirosis  

PubMed Central

Background: Leptospirosis is one of the most under diagnosed and underreported disease in both developed and developing countries including India. It is established that environmental conditions and occupational habit of the individuals put them at risk of acquiring disease, which varies from community to community. Various seroprevalence studies across the world have documented emerging situation of this neglected tropical disease, but limited have probed to identify the risk factors, especially in India. Objectives: The objective of this study was to identify the environmental and occupational risk factors associated with the disease in Udupi District. Materials and Methods: This population-based case-control study was carried out in Udupi, a District in Southern India from April 2012 until August 2012. Udupi is considered to be endemic for Leptospirosis and reported 116 confirmed cases in the year 2011. Seventy of 116 laboratory confirmed cases and 140 sex matched neighborhood healthy controls participated in the study. A predesigned, semi-structured and validated questionnaire was used for data collection through house to house visit and observations were noted about environmental conditions. Univariate analysis followed by multivariate analysis (back ward conditional logistic regression) was performed by using STATA version 9.2 (StataCorp, College Station, TX, USA) to identify potential risk factors. Results: Occupational factors such as outdoor activities (matched odds ratio [OR] of 3.95, 95% confidence interval [CI]: 1.19-13.0), presence of cut or wound at body parts during work (matched OR: 4.88, CI: 1.83-13.02) and environmental factors such as contact with rodents through using the food materials ate by rat (matched OR: 4.29, CI: 1.45-12.73) and contact with soil or water contaminated with urine of rat (matched OR: 4.58, CI: 1.43-14.67) were the risk factors identified to be associated with disease. Conclusion: Leptospirosis is still considered as neglected disease in the district. Early diagnosis and prompt treatment of cases can save many lives. However, there is a need of integrated rodent control measures with great effort to increase awareness and education among subjects in controlling the disease. PMID:24741223

Kamath, Ramachandra; Swain, Subhashisa; Pattanshetty, Sanjay; Nair, N Sreekumaran

2014-01-01

190

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 affecting…

Roby, Douglas E.

2012-01-01

191

Study of the use of a nonlinear, rate-limited filter on pilot control signals  

NASA Technical Reports Server (NTRS)

The use of a nonlinear, rate limited filter for rejecting the remnant (noise) in a pilot's control signal was studied through both an analytical study using pilot models and a simulation study using experienced test pilots. The nonlinear filter was compared with a linear filter and with no filter for both attitude and altitude control tasks. The results show that the nonlinear filter does promote rapid, steady maneuvering better than either the linear filter or the no filter condition. In addition, if the rate limit in the nonlinear filter is set so that it is too restrictive, a pilot induced unstable altitude oscillation can result.

Adams, J. J.

1978-01-01

192

Intrinsic near-24-h pacemaker period determines limits of circadian entrainment to a weak synchronizer in humans  

NASA Technical Reports Server (NTRS)

Endogenous circadian clocks are robust regulators of physiology and behavior. Synchronization or entrainment of biological clocks to environmental time is adaptive and important for physiological homeostasis and for the proper timing of species-specific behaviors. We studied subjects in the laboratory for up to 55 days each to determine the ability to entrain the human clock to a weak circadian synchronizing stimulus [scheduled activity-rest cycle in very dim (approximately 1.5 lux in the angle of gaze) light-dark cycle] at three approximately 24-h periods: 23.5, 24.0, and 24.6 h. These studies allowed us to test two competing hypotheses as to whether the period of the human circadian pacemaker is near to or much longer than 24 h. We report here that imposition of a sleep-wake schedule with exposure to the equivalent of candle light during wakefulness and darkness during sleep is usually sufficient to maintain circadian entrainment to the 24-h day but not to a 23.5- or 24.6-h day. Our results demonstrate functionally that, in normally entrained sighted adults, the average intrinsic circadian period of the human biological clock is very close to 24 h. Either exposure to very dim light and/or the scheduled sleep-wake cycle itself can entrain this near-24-h intrinsic period of the human circadian pacemaker to the 24-h day.

Wright, K. P. Jr; Hughes, R. J.; Kronauer, R. E.; Dijk, D. J.; Czeisler, C. A.

2001-01-01

193

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

NASA Astrophysics Data System (ADS)

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 for a European participation in human exploration and to estimate their influence on the Life Sciences and Life Support requirements; (ii) for selected mission scenarios, to critically assess the limiting factors for human health, wellbeing, and performance and to recommend relevant countermeasures; (iii) for selected mission scenarios, to critically assess the potential of Advanced Life Support Developments and to pro-pose a European strategy including terrestrial applications; (iv) to critically assess the feasibility of existing facilities and technologies on ground and in space as test-beds in preparation for human exploratory missions and to develop a test plan for ground and ISS campaigns; (v) to develop a roadmap for a future European strategy towards human exploratory missions, including preparatory activities and terrestrial applications and benefits. Two scenarios for a Mars mission were selected: (i) with a 30 days stay on Mars, and (ii) with about 500 days stay on Mars. The impact on human health, perform-ance and well being has been investigated from the view point of (i) the effects of microgravity (during space travel), reduced gravity (on Mars) and abrupt gravity changes (during launch and landing), (ii) the effects of cosmic radiation including solar particle events, (iii) psychological issues as well as general health care. Coun-termeasures as well as necessary research using ground-based testbeds and/or the ISS have been defined. The need for highly intelligent autonomous diagnostic and therapy systems was emphasized. Advanced life support systems with a high degree of autonomy and regenerative capacity and synergy effects were considered where bioregenerative life support systems and biodiagnostic systems become essential especially for the long-term Mars scenario. The considerations have been incorpo-rated into a roadmap for a future European strategy in human health issues for a potential European participation in a cooperative international exploration of our solar system by humans. Ref. Horneck et al, 2003, HUMEX, study on the Survivability and Adaptation of Humans to Long-Duration Exploratory Missions, ESA SP 1264

Horneck, G.; Humex Team

194

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

195

Looking toward the Future: A Case Study of Open Source Software in the Humanities  

ERIC Educational Resources Information Center

In this article Harvey Quamen examines how the philosophy of open source software might be of particular benefit to humanities scholars in the near future--particularly for academic journals with limited financial resources. To this end he provides a case study in which he describes his use of open source technology (MySQL database software and…

Quamen, Harvey

2006-01-01

196

Foot Pain and Mobility Limitations in Older Adults: The Framingham Foot Study  

PubMed Central

Background. Foot pain is very common in the general population and has been shown to have a detrimental impact on health-related quality of life. This is of particular concern in older people as it may affect activities of daily living and exacerbate problems with balance and gait. The objective of this study is to evaluate the independent relationships between foot pain and mobility limitation in a population of community-dwelling older adults. Methods. Population-based cross-sectional study. Participants (n = 1,544) from the Framingham Foot Study (2002–2008) were assessed for physical performance. Foot pain was documented using the question “On most days, do you have pain, aching, or stiffness in either foot?” Mobility limitation was assessed using the Short Physical Performance Battery, dichotomized using 1–9 as an indicator of mobility limitation and 10–12 as no mobility limitation. Results. Foot pain was reported by 19% of men and 25% of women. After adjusting for age, obesity, smoking status, and depression, foot pain was significantly associated with mobility limitation in both men (odds ratio = 2.00, 95% confidence interval 1.14 – 3.50; p = .016) and women (odds ratio = 1.59, 95% confidence interval 1.03 – 2.46; p = .037). Conclusion. In our study of older adults from the Framingham Foot Study, foot pain was associated with an increased odds of having mobility limitation in both men and women. Clinicians should consider assessment of foot pain in general examinations of older adults who are at risk of mobility limitation. PMID:23704204

2013-01-01

197

On memetic Differential Evolution frameworks: A study of advantages and limitations in hybridization  

Microsoft Academic Search

This paper aims to study the benefits and limitations in the hybridization of the differential evolution with local search algorithms. In order to perform this study, the performance of three memetic algorithms employing a differential evolution as an evolutionary framework and several local search algorithms adaptively coordinated by means of a fitness diversity logic have been analyzed. The performance of

Ferrante Neri; Ville Tirronen

2008-01-01

198

Selection of T lymphocytes bearing limited T-cell receptor beta chains in the response to a human pathogen.  

PubMed Central

Delayed-type hypersensitivity (DTH) is a classic measure of T-cell responsiveness to foreign antigen. To estimate the extent of the T-cell repertoire in the DTH response to a human pathogen, we measured T-cell receptor (TCR) beta-chain variable-region (V beta) gene usage in reversal reactions in leprosy. Reversal reactions represent naturally occurring DTH responses in leprosy, in which augmentation of T-cell responses to Mycobacterium leprae is concomitant with clearance of bacilli from lesions. T cells using the V beta 6-, V beta 12-, V beta 14-, and V beta 19-encoded TCRs were strikingly overrepresented in the lesions of patients as compared to blood and pre-DTH lesions from the same individuals. Furthermore, these data indicate a possible association between the predominant expression of a V beta gene segment in lesions and the major histocompatibility complex class II haplotype of the individual. V beta 6 was prominent in the lesions of four patients who were DR15, a marker of resistance in leprosy infection. Sequence analysis of V beta 6 TCRs showed frequent use of V beta 6.1 and J beta 2.7 gene segments and a conserved amino acid motif in the V-J junction in a reversal-reaction lesion, but not in blood from the same patient. The limited TCR repertoire expressed by the infiltrating T cells suggests that a limited set of antigens is recognized in the DTH response to a human pathogen. We suggest that the mechanism by which major histocompatibility complex haplotype influences DTH in this disease involves the presentation of specific peptides, with subsequent selection of specific TCRs followed by local oligoclonal expansion. Images PMID:8419921

Wang, X H; Ohmen, J D; Uyemura, K; Rea, T H; Kronenberg, M; Modlin, R L

1993-01-01

199

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 focus…

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

1998-01-01

200

CUE, SOCIAL STUDIES HUMANITIES MEDIA GUIDE.  

ERIC Educational Resources Information Center

THIS DOCUMENT IS ONE OF A SERIES OF MEDIA GUIDES SPONSORED BY THE NEW YORK STATE EDUCATION DEPARTMENT UNDER THE CUE SYSTEM. THE HUMANITIES AREAS ARE DIVIDED INTO 11 DIFFERENT TOPICS. WITHIN EACH TOPIC IS A SERIES OF SUGGESTED FILM AND TELEVISION SUBJECTS. A DISCUSSION IS GIVEN ON EACH OF THE SUBJECTS INCLUDING A SYNOPSIS, A STATEMENT OF PURPOSE,…

BROWN, ROBERT M.; AND OTHERS

201

Human-Behaviour Study with Situation Lattices  

Microsoft Academic Search

Most research in the area of smart environments focuses on improving the accuracy with which human activities can be recognised. Relatively little research has been done into how designers can gain insights into the behaviours their systems are observing, and feed these insights back into improving systems design. We describe a mathematical structure, the situation lattice, and show how it

Juan Ye; Simon A. Dobson

2009-01-01

202

Theoretical assessment of the maximum obtainable power in wireless power transfer constrained by human body exposure limits in a typical room scenario  

NASA Astrophysics Data System (ADS)

In this study, the maximum received power obtainable through wireless power transfer (WPT) by a small receiver (Rx) coil from a relatively large transmitter (Tx) coil is numerically estimated in the frequency range from 100 kHz to 10 MHz based on human body exposure limits. Analytical calculations were first conducted to determine the worst-case coupling between a homogeneous cylindrical phantom with a radius of 0.65 m and a Tx coil positioned 0.1 m away with the radius ranging from 0.25 to 2.5 m. Subsequently, three high-resolution anatomical models were employed to compute the peak induced field intensities with respect to various Tx coil locations and dimensions. Based on the computational results, scaling factors which correlate the cylindrical phantom and anatomical model results were derived. Next, the optimal operating frequency, at which the highest transmitter source power can be utilized without exceeding the exposure limits, is found to be around 2 MHz. Finally, a formulation is proposed to estimate the maximum obtainable power of WPT in a typical room scenario while adhering to the human body exposure compliance mandates.

Chen, Xi Lin; De Santis, Valerio; Esai Umenei, Aghuinyue

2014-07-01

203

Implications of Limits of Detection of Various Methods for Bacillus anthracis in Computing Risks to Human Health? †  

PubMed Central

Used for decades for biological warfare, Bacillus anthracis (category A agent) has proven to be highly stable and lethal. Quantitative risk assessment modeling requires descriptive statistics of the limit of detection to assist in defining the exposure. Furthermore, the sensitivities of various detection methods in environmental matrices are vital information for first responders. A literature review of peer-reviewed journal articles related to methods for detection of B. anthracis was undertaken. Articles focused on the development or evaluation of various detection approaches, such as PCR, real-time PCR, immunoassay, etc. Real-time PCR and PCR were the most sensitive methods for the detection of B. anthracis, with median instrument limits of detection of 430 and 440 cells/ml, respectively. There were very few peer-reviewed articles on the detection methods for B. anthracis in the environment. The most sensitive limits of detection for the environmental samples were 0.1 CFU/g for soil using PCR-enzyme-linked immunosorbent assay (ELISA), 17 CFU/liter for air using an ELISA-biochip system, 1 CFU/liter for water using cultivation, and 1 CFU/cm2 for stainless steel fomites using cultivation. An exponential dose-response model for the inhalation of B. anthracis estimates of risk at concentrations equal to the environmental limit of detection determined the probability of death if untreated to be as high as 0.520. Though more data on the environmental limit of detection would improve the assumptions made for the risk assessment, this study's quantification of the risk posed by current limitations in the knowledge of detection methods should be considered when employing those methods in environmental monitoring and cleanup strategies. PMID:19648357

Herzog, Amanda B.; McLennan, S. Devin; Pandey, Alok K.; Gerba, Charles P.; Haas, Charles N.; Rose, Joan B.; Hashsham, Syed A.

2009-01-01

204

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

205

Human brain cancer studied by resonance Raman spectroscopy  

E-print Network

Human brain cancer studied by resonance Raman spectroscopy Yan Zhou Cheng-Hui Liu Yi Sun Yang Pu://biomedicaloptics.spiedigitallibrary.org/ on 11/16/2012 Terms of Use: http://spiedl.org/terms #12;Human brain cancer studied by resonance Raman, and 13,700 deaths from brain and other nervous system cancers were reported in the United States

Sun, Yi

206

Policy and Procedures 1 HUMAN DEVELOPMENT AND FAMILY STUDIES  

E-print Network

, to the profession and to the wider community. Core Values The Department of Human Development and Family Studies respect Service to the university and the profession #12;Policy and Procedures 5 Outreach and communityPolicy and Procedures 1 HUMAN DEVELOPMENT AND FAMILY STUDIES POLICY AND PROCEDURES MANUAL

Rock, Chris

207

HUMAN PERFORMANCE STUDIES The mission of the Department of  

E-print Network

and service to the community and profession. The department offers a BA degree in Athletic Training, a BAHUMAN PERFORMANCE STUDIES The mission of the Department of Human Performance Studies at Wichita. The department also has a comprehensive Human Performance Laboratory that is available for students completing

208

REPORTING NEEDS FOR STUDIES OF ENVIRONMENTAL CHEMICALS IN HUMAN MILK  

E-print Network

REPORTING NEEDS FOR STUDIES OF ENVIRONMENTAL CHEMICALS IN HUMAN MILK Michael N. Bates School, USA Studies of environmental chemicals in human milk have been carried out in many coun- tries trends in exposure to chemicals, for research into the determinants of environmental chemicals in milk

California at Berkeley, University of

209

Roadmap: Human Development and Family Studies Child and Youth Development -  

E-print Network

Roadmap: Human Development and Family Studies ­ Child and Youth Development - Bachelor of Science Child Development 3 See note 1 on page 2 HDFS 24013 Early Adolescence 3 Kent Core Requirements 3 See or upper division) 3 See note 3 on page 3 #12;Roadmap: Human Development and Family Studies ­ Child

Sheridan, Scott

210

Recognizing face sketches by a large number of human subjects: A perception-based study for facial distinctiveness  

Microsoft Academic Search

Understanding how humans recognize face sketches drawn by artists is of significant value to both criminal investigators and researchers in computer vision, face biometrics and cognitive psychology. However, large scale experimental studies of hand-drawn face sketches are still very limited in terms of the number of artists, the number of sketches, and the number of human evaluators involved. In this

Yong Zhang; Steve Ellyson; Anthony Zone; Priyanka Gangam; John R. Sullins; Christine McCullough; Shaun J. Canavan; Lijun Yin

2011-01-01

211

Antisense tools for functional studies of human Argonaute proteins  

PubMed Central

The Argonaute proteins play essential roles in development and cellular metabolism in many organisms, including plants, flies, worms, and mammals. Whereas in organisms such as Caenorhabditis elegans and Arabidopsis thaliana, creation of Argonaute mutant strains allowed the study of their biological functions, in mammals the application of this approach is limited by its difficulty and in the specific case of Ago2 gene, by the lethality of such mutation. Hence, in human cells, functional studies of Ago proteins relied on phenotypic suppression using small interfering RNA (siRNA) which involves Ago proteins and the RNA interference mechanism. This bears the danger of undesired or unknown interference effects which may lead to misleading results. Thus, alternative methods acting by different regulatory mechanisms would be advantageous in order to exclude unspecific effects. The knockdown may be achieved by using specific antisense oligonucleotides (asONs) which act via an RNase H-dependent mechanism, not thought to interfere with processes in which Agos are involved. Different functional observations in the use of siRNA versus asONs indicate the relevance of this assumption. We developed asONs specific for the four human Agos (hAgos) and compared their activities with those obtained by siRNA. We confirm that hAgo2 is involved in microRNA (miRNA)- and in siRNA-mediated silencing pathways, while the other hAgos play a role only in miRNA-based gene regulation. Using combinations of asONs we found that the simultaneous down-regulation of hAgo1, hAgo2, and hAgo4 led to the strongest decrease in miRNA activity, indicating a main role of these proteins. PMID:20935067

Mescalchin, Alessandra; Detzer, Anke; Weirauch, Ulrike; Hahnel, Maximilian J.; Engel, Christina; Sczakiel, Georg

2010-01-01

212

Antisense tools for functional studies of human Argonaute proteins.  

PubMed

The Argonaute proteins play essential roles in development and cellular metabolism in many organisms, including plants, flies, worms, and mammals. Whereas in organisms such as Caenorhabditis elegans and Arabidopsis thaliana, creation of Argonaute mutant strains allowed the study of their biological functions, in mammals the application of this approach is limited by its difficulty and in the specific case of Ago2 gene, by the lethality of such mutation. Hence, in human cells, functional studies of Ago proteins relied on phenotypic suppression using small interfering RNA (siRNA) which involves Ago proteins and the RNA interference mechanism. This bears the danger of undesired or unknown interference effects which may lead to misleading results. Thus, alternative methods acting by different regulatory mechanisms would be advantageous in order to exclude unspecific effects. The knockdown may be achieved by using specific antisense oligonucleotides (asONs) which act via an RNase H-dependent mechanism, not thought to interfere with processes in which Agos are involved. Different functional observations in the use of siRNA versus asONs indicate the relevance of this assumption. We developed asONs specific for the four human Agos (hAgos) and compared their activities with those obtained by siRNA. We confirm that hAgo2 is involved in microRNA (miRNA)- and in siRNA-mediated silencing pathways, while the other hAgos play a role only in miRNA-based gene regulation. Using combinations of asONs we found that the simultaneous down-regulation of hAgo1, hAgo2, and hAgo4 led to the strongest decrease in miRNA activity, indicating a main role of these proteins. PMID:20935067

Mescalchin, Alessandra; Detzer, Anke; Weirauch, Ulrike; Hahnel, Maximilian J; Engel, Christina; Sczakiel, Georg

2010-12-01

213

Two photon microscopy for studies of xenobiotics in human skin  

NASA Astrophysics Data System (ADS)

For successful uptake and distribution of drugs from transdermal formulations, it is important to understand the skin barrier function. Innovative advances in modern microscopy have provided valuable tools to study the interaction between the skin and xenobiotics. Two-photon microscopy (TPM) allows non-invasive visualization of fluorescent compounds in the skin. The advantages of TPM over conventional confocal microscopy are better light penetration into highly scattering and absorbing tissue such as human skin, improved detection efficiency, limited out of focus photobleaching and reduced phototoxic effects. We present TPM as an alternative non-invasive in vitro method to study chemical penetration enhancement of fluorescent model drugs. The permeability of sulforhodamine B (SRB) through human epidermis was measured with vertical diffusion cells. The absorption was visualized using TPM after 24 h passive diffusion. We have evaluated variations in physicochemical parameters controlling dermal drug uptake induced by the penetration enhancer oleic acid according to methods previously described by Yu et al. Optical sectioning by TPM was compared with cryosectioning. Oleic acid significantly increased penetration of sulforhodamine. TPM images demonstrate a four-fold increase in the partition coefficient. In addition, a six-fold increase in the concentration gradient was found over stratum corneum. Better light penetration and detection efficiency increase maximum imaging depth in TPM compared to conventional confocal microscopy, however loss of signal due to scattering and absorption is still significant and will affect distribution profiles generated by optical sectioning. A true concentration profile cannot be established without better knowledge about signal losses in the skin.

Simonsson, Carl; Smedh, Maria; Jonson, Charlotte; Karlberg, Ann-Therese; Ericson, Marica B.

2007-07-01

214

A Practical Guide to Time—Frequency Analysis in the Study of Human Motor Behavior: The Contribution of Wavelet Transform  

Microsoft Academic Search

The authors present a practical guide for studying nonstationary data on human motor behavior in a time-frequency representation. They explain the limits of classical methods founded exclusively on the time or frequency basis and then answer those limits with the windowed Fourier transform and the wavelet transform (WT) methods, both of which are founded on timefrequency bases. The authors stress

Johann Issartel; Ludovic Marin; Philippe Gaillot; Thomas Bardainne; Marielle Cadopi

2006-01-01

215

Distribution Limits of Batrachochytrium dendrobatidis: A Case Study in the Rocky Mountains, USA  

Microsoft Academic Search

Knowledge of the environmental constraints on a pathogen is critical to predict- ing its dynamics and effects on populations. Batrachochytrium dendrobatidis (Bd), an aquatic fungus that has been linked with widespread amphibian declines, is ubiquitous in the Rocky Mountains. As part of assessing the distribution limits of Bd in our study area, we sampled the water column and sediments for

Blake R. Hossack; Erin Muths; Chauncey W. Anderson; Julie D. Kirshtein; Paul Stephen Corn

2009-01-01

216

A Guide to the Standard Course of Study for Limited English Proficient Students, Grades K-5.  

ERIC Educational Resources Information Center

This curriculum guide is designed to help both English-as-a-Second-Language (ESL) and regular classroom teachers improve instruction for limited-English-proficient (LEP) students in the elementary grades in the areas of math, science, social studies, and English language arts. This K-5 guide provides models for teachers who need to modify…

North Carolina State Dept. of Public Instruction, Raleigh. Instructional Services.

217

Reconceptualizing Treatment Goals from Language Impairment to Functional Limitations: A Case Study  

ERIC Educational Resources Information Center

This case study of a preadolescent boy with severe expressive and receptive language impairments illustrates treatment focused on the functional limitations on the child's daily academic activities and social participation. Treatment goals incorporated language comprehension objectives into the student's reading program and language use objectives…

Skarakis-Doyle, Elizabeth

2005-01-01

218

Detailed ice studies under atmospheric conditions - potential and inherent limitations of the molecular beam method  

Microsoft Academic Search

Molecular beam techniques are traditionally applied under high vacuum to obtain detailed information about gas-surface interactions and to probe surface properties. We here evaluate the potential and limitations for molecular beam studies of ice surfaces at elevated pressures using direct simulation Monte Carlo (DSMC) calculations. Simplified experimental setups are treated and the results demonstrate that well-defined experiments are feasible at

Jan B. C. Pettersson; Xiangrui Kong

2010-01-01

219

Scientific Study of Malnutrition as a Limiting Factor in the Development of Education.  

ERIC Educational Resources Information Center

This study on malnutrition as a limiting factor in the development of education (and, hence, in socioeconomic development generally) was presented to the UNESCO Seminar on Education, Nutrition, Agriculture and Man. The paper reports on recent research showing that the development of the central nervous system in very young children (including the…

Picasso de Oyague, Alfredo

220

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...

221

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...

222

Prospective study of thoracoscopic limited resection for ground-glass opacity selected by computed tomography  

Microsoft Academic Search

BackgroundWith recent advances in low-dose helical computed tomography (CT), detection of ground-glass opacity (GGO) has increased. The aim of this study was to correlate high-resolution CT (HRCT) findings with pathologic features and to evaluate the efficacy of thoracoscopic limited resection for focal GGO, which were selected based on HRCT findings.

Masao Nakata; Shigeki Sawada; Hideyuki Saeki; Shigemitsu Takashima; Hiroshi Mogami; Norihiro Teramoto; Kenji Eguchi

2003-01-01

223

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. PMID:23423644

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

2012-01-01

224

An Interdisciplinary Deer and Human Population Study  

NSDL National Science Digital Library

This activity helps the learner answer the question: "What environmental problems arise due to animal and human overpopulation and what might need to be done to combat these problems?" Learners play a game that simulates population sampling in an imaginary state park. After the game is completed, each park must decide if they are at the carrying capacity for their park or out of equilibrium. Learners write a proposal detailing how they plan to correct their deer population problem and present it to the group (the Department of Natural Resources). This lesson is described as an interdisciplinary unit and includes literature and math curriculum connections.

Webb, William J.

2009-01-01

225

Implications of human tissue studies for radiation protection  

SciTech Connect

Through radiochemical analysis of voluntary tissue donations, the U.S. Transuranium and Uranium Registries (USTR) are gaining improved understanding of the distribution and biokinetics of actinide elements in occupationally exposed persons. Evaluation of the first two whole-body contributions to the USTR revealed an inverse proportionality between actinide concentration and bone ash. The analysis of a whole body with significant /sup 241/Am deposition indicated a significantly shorter half-time in liver and a greater fraction resident in the skeleton than predicted by existing models. Other studies with tissues obtained at autopsy suggest that existing biokinetic models for /sup 238/Pu and /sup 241/Am and the currently accepted models and limits on intake, which use these models as their basis, may be inaccurately implying that revisions of existing safety standards may be necessary. Other studies of the registries are designed to evaluate in-vivo estimates of actinide deposition with those derived from postmortem tissue analysis, to compare results of animal experiments with human data, and to review histopathologic slides for tissue changes that might be attributable to exposure to transuranic elements. The implications of these recent findings and other work of the registries is discussed from the standpoint of this potential effect on biokinetic modeling, internal dose assessment, and safety standards and operational health physics practices.

Kathren, R.L.

1988-08-01

226

Improving a method for the study of limit cycles of the Lienard equation  

E-print Network

In recent papers we have introduced a method for the study of limit cycles of the Lienard system: dot{x}=y-F(x), dot{y}=-x, where F(x) is an odd polynomial. The method gives a sequence of polynomials R_n(x), whose roots are related to the number and location of the limit cycles, and a sequence of algebraic approximations to the bifurcation set of the system. In this paper, we present a variant of the method that gives very important qualitative and quantitative improvements.

Hector Giacomini; Sebastien Neukirch

1997-10-02

227

Some limitations on the external validity of psychotherapy efficacy studies and suggestions for future research.  

PubMed

Increased emphasis on identifying empirically supported treatments (ESTs) has enhanced the scientific basis for psychotherapy practice, but uncritical acceptance of ESTs as the basis for credentialing and policy decisions risks stifling innovation and creativity in the field. There are limitations inherent in efficacy studies of psychotherapy that can constrain external validity. This article discusses several limitations on the external validity of efficacy studies, as well as other issues related to evaluating psychotherapy outcome research. These limitations and concerns include: 1) the practice of maximizing homogeneity by selecting participants diagnosed with a single Axis I disorder; 2) the practice of requiring manualized therapies for efficacy research; 3) the assumption that lasting and meaningful changes occur and can be assessed within a relatively short time frame; 4) the assumption that valid assessments of outcome can be conducted in randomized control trials studies without concern for researcher allegiance; and 5) the view that evidence of effectiveness from non-RCT design studies can be ignored. Finally, alternative research approaches for studying psychotherapy that can potentially supplement knowledge gained from efficacy studies and foster continued innovation and creativity in the field are discussed. PMID:23091884

Shean, Glenn D

2012-01-01

228

Medieval Studies The School of Humanities  

E-print Network

of Chivalry · MDST368Mythologies · MDST370Introduction to Traditional Chinese Poetry · MDST375Introduction to Classical Chinese Literature #12;Medieval Studies 229 Classical Studies MDST 101 Elementary Latin I MDST 102 MDST 320 Directed Readings in Medieval Studies MDST 368 Mythologies French Studies MDST 404 Beginnings

Richards-Kortum, Rebecca

229

Sociology and American Studies: A Case Study in the Limits of Interdisciplinarity  

Microsoft Academic Search

American Studies is an academic discipline whose object of study is the United States of America and everything associated\\u000a with it, and American sociologists largely ignore it. American Studies largely ignores American sociology. What causes this\\u000a mutual exclusion? An outline of the disciplinary history of American Studies and journal article citation data show that the\\u000a relationship between sociology and American

Joshua Kjerulf Dubrow

230

Study of the use of a nonlinear, rate limited, filter on pilot control signals  

NASA Technical Reports Server (NTRS)

The use of a filter on the pilot's control output could improve the performance of the pilot-aircraft system. What is needed is a filter with a sharp high frequency cut-off, no resonance peak, and a minimum of lag at low frequencies. The present investigation studies the usefulness of a nonlinear, rate limited, filter in performing the needed function. The nonlinear filter is compared with a linear, first order filter, and no filter. An analytical study using pilot models and a simulation study using experienced test pilots was performed. The results showed that the nonlinear filter does promote quick, steady maneuvering. It is shown that the nonlinear filter attenuates the high frequency remnant and adds less phase lag to the low frequency signal than does the linear filter. It is also shown that the rate limit in the nonlinear filter can be set to be too restrictive, causing an unstable pilot-aircraft system response.

Adams, J. J.

1977-01-01

231

Medieval Studies The School of Humanities  

E-print Network

Chance Gilbert Morris Cuthbertson Michael Maas Donald Ray Morrison Deborah Nelson-Campbell Associate the Medieval Studies web site at http://medieval.rice.edu. Classical Studies MDST 101 Elementary Latin I MDST

Richards-Kortum, Rebecca

232

Religious Studies The School of Humanities  

E-print Network

, meth- odological studies, or ethics/philosophy of religion #12;248 DEPARTMENTS / Religious Studies, normative, and sociocultural approaches to the study of religion) and religious traditions (Africanreligions hours (24 for double-majors) must include the following requirements: ·RELI 101 Introduction to Religion

Richards-Kortum, Rebecca

233

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. PMID:23423909

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

2013-01-01

234

78 FR 71707 - MAP-21 Comprehensive Truck Size and Weight Limits Study Public Meeting and Outreach Sessions  

Federal Register 2010, 2011, 2012, 2013

...within Federal truck size and weight (TSW) limits and trucks legally...Comprehensive Truck Size and Weight Limits Study. This will include...overall synthesis of the preceding body of work. The second peer review...Review of the DOT Truck Size and Weight Limits Study will hold a...

2013-11-29

235

HUMANITIES & SOCIAL STUDIES Year One Enrolment Information  

E-print Network

in the Schools of:- English, Communication & Philosophy; Modern Languages; History, Archaeology & Religion & Social Studies Degree Programmes & their `Home' Schools SECTION SIX Definition of terms (eg `module') #12

Davies, Christopher

236

Religious Studies The School of Humanities  

E-print Network

,andsocioculturalapproachestothestudyofreligion)andreligious traditions (African religions, Buddhism, Christianity, comparative religions, Hinduism,Africanreligion,Buddhism,comparativestudies,cross-cultural studies,Islam,Hinduism,methodologicalstudies,orethics/philosophy ofreligion Honors Program

Richards-Kortum, Rebecca

237

Electron tomography study of isolated human centrioles.  

PubMed

Centrioles are components of the centrosome, which is present in most eukaryotic cells (from protozoa to mammals). They organize the microtubule skeleton during interphase and the mitotic spindle during cell division. In ciliate cells, centrioles form basal bodies that are involved in cellular motility. Despite their important roles in biology, the detailed structure of centrioles remains obscure. This work contributes to a more complete model of centriole structure. The authors used electron tomography of isolated centrosomes from the human lymphoblast KE37 to explore the details of subdistal appendages and centriole lumen organization in mother centrioles. Their results reveal that each of the nine subdistal appendages is composed of two halves (20 nm diameter each) fused in a 40 nm tip that extends 100 nm from where it anchors to microtubules. The centriole lumen is filled at the distal domain by a 45 nm periodic stack of rings. Each ring has a 30 nm diameter, is 15 nm thick, and appears to be tilted at 53 degrees perpendicular to the centriole axis. The rings are anchored to microtubules by arms. Based on their results, the authors propose a model of the mother centriole distal structure. PMID:18837435

Ibrahim, Rana; Messaoudi, Cédric; Chichon, Francisco Javier; Celati, Claude; Marco, Sergio

2009-01-01

238

Human Stem Cell-Derived Neurons: A System to Study Human Tau Function and Dysfunction  

PubMed Central

Background Intracellular filamentous deposits containing microtubule-associated protein tau constitute a defining characteristic of many neurodegenerative disorders. Current experimental models to study tau pathology in vitro do not usually recapitulate the tau expression pattern characteristic of adult human brain. In this study, we have investigated whether human embryonic stem cell-derived neurons could be a good model to study human tau distribution, function and dysfunction. Methodology/Principal Findings Using RT-PCR, immunohistochemistry, western blotting and cell transfections we have investigated whether all 6 adult human brain tau isoforms are expressed in neurons derived from human embryonic and fetal stem cells and whether 4 repeat tau over-expression alone, or with the F3 tau repeat fragment, (amino acid 258–380 of the 2N4R tau isoform with the ?K280 mutation) affects tau distribution. We found that the shortest 3 repeat tau isoform, similarly to human brain, is the first to be expressed during neuronal differentiation while the other 5 tau isoforms are expressed later. Over expression of tau with 4 repeats affects tau cellular distribution and the short tau F3 fragment appears to increase tau phosphorylation but this effect does not appear to be toxic for the cell. Conclusions Our results indicate that human embryonic stem cell-derived neurons express all 6 tau isoforms and are a good model in which to study tau physiology and pathology. PMID:21085657

Iovino, Mariangela; Patani, Rickie; Watts, Colin; Chandran, Siddharthan; Spillantini, Maria Grazia

2010-01-01

239

The transduction of rat submandibular glands by an adenoviral vector carrying the human growth hormone gene is associated with limited and reversible changes at the infusion site.  

PubMed

Adenoviral vectors have been shown to efficiently deliver exogenous genes to salivary glands and have therefore been investigated as tools for the treatment of human disease. The purpose of this study was to evaluate the response of F344 rats to intraductal infusion of the right submandibular salivary gland with an adenoviral vector encoding the gene for human growth hormone (AdCMVhGH). Co-administration of hydroxychloroquine (HCQ) was used to redirect the secretion of human growth hormone (hGH) from saliva into serum. This paper documents the findings of the pathology evaluation of this National Toxicology Program study. The right submandibular salivary gland (infusion site) was the primary target organ, with microscopic lesions characteristic of a mild to moderate insult observed at 3 days post infusion in vector exposed animals. These lesions were characterized by variable degrees of acute glandular inflammation, degeneration and necrosis, with more severe lesions in the higher dose groups. Rats at 28 days post infusion had milder inflammation, degeneration and necrosis compared to day 3 rats, with variable degrees of regeneration. In conclusion, the effects on the salivary glands are reversible as indicated by the milder inflammation and degeneration in the day 28 rats concomitant with mild to moderate regeneration. Therefore, the vector appears relatively innocuous with limited tissue toxicity. [The supplemental data referenced in this paper is not printed in this issue of Toxicologic Pathology. It is available as a downloadable file in the online edition of Toxicologic Pathology, 34(4). In order to access the full article online, you must have either an individual subscription or a member subscription accessed through www.toxpath.org.]. PMID:16844666

Elmore, S; Lanning, L; Allison, N; Vallant, M; Nyska, A

2006-01-01

240

Numerical Study of the Pedestal MHD Stability Limit on Upper and Lower Separatrix Triangularies  

NASA Astrophysics Data System (ADS)

The dependence of the magnetohydrodynamic (MHD) stability limit of the edge plasma on the upper and lower triangularities of a lower single null configuration is examined numerically. Although high triangularity has long been known to increase the pedestal height and improve confinement, the effect of varying upper and lower triangularities separately has never been investigated systematically. To study this dependence, Grad Shafranov equilibrium files are created using the EFIT code and varying triangularities while a constant pressure profile characteristic of experimental measurements is maintained. The edge current is constrained to match the Sauter bootstrap current model using measured edge plasma profiles. These equilibria are used as inputs for the ELITE code to determine the MHD stability limit. Results from this study can be used for optimization of the boundary geometry and control of the edge pedestal pressure.

von der Linden, J.; Leonard, A. W.; Groebner, R. J.; Osborne, T. H.; Parks, P. B.

2008-11-01

241

Medieval Studies The School of Humanities  

E-print Network

: Courtship, Love, and Marriage in the Age of Chivalry · MDST368Mythologies · MDST370Introduction to Traditional Chinese Poetry · MDST375Introduction to Classical Chinese Literature #12;2 departments / Medieval Studies Classical Studies MDST 101 Elementary Latin I MDST 102 Elementary Latin II MDST 211 Intermediate

Richards-Kortum, Rebecca

242

Medieval Studies The School of Humanities  

E-print Network

, and Marriage in the Age of Chivalry · MDST368Mythologies · MDST370Introduction to Traditional Chinese Poetry · MDST375Introduction to Classical Chinese Literature #12;240 departments / Medieval Studies Classical MDST 368 Mythologies French Studies MDST 404 Beginnings of Language and Literature of France MDST 410

Richards-Kortum, Rebecca

243

Medieval Studies The School of Humanities  

E-print Network

Mythologies · MDST 370 Introduction to Traditional Chinese Poetry · MDST 375 Introduction to Classical Chinese Art and Architecture in Northern Europe, 1300­1500 #12;222 departments / Medieval Studies Classical Mythologies French Studies MDST 404 Beginnings of Language and Literature MDST 410 The Literary and Historical

Richards-Kortum, Rebecca

244

The Social Studies Contribution: Meaning and Humanism  

ERIC Educational Resources Information Center

The author shows that it is through knowledge of the social studies that students become able to apply knowledge from mathematics, science, and other disciplines. Ultimately, the social studies allows them to make life more meaningful by helping to establish what is valued in life. (Author/RM)

Berger, Michael L.

1976-01-01

245

Z-scan studies and optical limiting of nanosecond laser pulses in neutral red dye  

Microsoft Academic Search

The nonlinear optical absorption, refraction and optical limiting behaviour of an organic dye, neutral red, were investigated under excitation with nanosecond laser pulses at 532nm. The nonlinear optical responses of the material were studied both in solution and solid film, made in methanol and polyvinyl alcohol, respectively, using single-beam Z-scan technique. The open aperture Z-scans of the solution samples displayed

Mathew George; C. I. Muneera; C. P. Singh; K. S. Bindra; S. M. Oak

2008-01-01

246

Exploring the Limits of Trigonometric Functions: Results and Reflections from a Pilot Study  

ERIC Educational Resources Information Center

In this paper, we report a pilot study on engaging a group of undergraduate students to explore the limits of sin(x)/x and tan(x)/x as x approaches to 0, with the use of non-graphic scientific calculators. By comparing the results in the pretest and the post-test, we found that the students had improvements in the tested items, which involved the…

Man, Yiu-Kwong; Poon, Kin-Keung

2014-01-01

247

Potential and Limitations of Echocontrast-Enhanced Ultrasonography in Acute Stroke Patients A Pilot Study  

Microsoft Academic Search

Background and Purpose—Ultrasonography (US) is a well-established method used to assess the brain-supplying arteries in the acute stroke setting. However, several technical and anatomic limitations are known to reduce its diagnostic accuracy and confidence level. Echocontrast agents (ECA) are known to improve the signal-to-noise ratio by enhancing the intensity of the reflecting Doppler signal. We undertook this prospective study to

Darius G. Nabavi; Dirk W. Droste; Vendel Kemeny; Gernot Schulte-Altedorneburg; Sepp Weber; E. Bernd Ringelstein

248

Numerical study of the long wavelength limit of the Toda lattice  

E-print Network

We present the first detailed numerical study of the Toda equations in $2+1$ dimensions in the limit of long wavelengths, both for the hyperbolic and elliptic case. We first study the formal dispersionless limit of the Toda equations and solve initial value problems for the resulting system up to the point of gradient catastrophe. It is shown that the break-up of the solution in the hyperbolic case is similar to the shock formation in the Hopf equation, a $1+1$ dimensional singularity. In the elliptic case, it is found that the break-up is given by a cusp as for the semiclassical system of the focusing nonlinear Schr\\"odinger equation in $1+1$ dimensions. The full Toda system is then studied for finite small values of the dispersion parameter $\\epsilon$ in the vicinity of the shocks of the dispersionless Toda equations. We determine the scaling in $\\epsilon$ of the difference between the Toda solution for small $\\epsilon$ and the singular solution of the dispersionless Toda system. In the hyperbolic case, the same scaling proportional to $\\epsilon^{2/7}$ is found as in the small dispersion limit of the Korteweg-de Vries and the defocusing nonlinear Schr\\"odinger equations. In the elliptic case, we obtain the same scaling proportional to $\\epsilon^{2/5}$ as in the semiclassical limit for the focusing nonlinear Schr\\"odinger equation. We also study the formation of dispersive shocks for times much larger than the break-up time in the hyperbolic case. In the elliptic case, an $L_{\\infty}$ blow-up is observed instead of a dispersive shock for finite times greater than the break-up time. The $\\epsilon$-dependence of the blow-up time is determined.

C. Klein; K. Roidot

2014-04-09

249

German and Slavic Studies The School of Humanities  

E-print Network

are accompanied by sections that conduct discussions and study sources in German. Upper-level literary courses179 German and Slavic Studies The School of Humanities CHAIR John Zammito PROFESSORS Peter Caldwell Degrees Offered: BA in German Studies, BA in Slavic Studies German The department offers instruction

Richards-Kortum, Rebecca

250

German and Slavic Studies The School of Humanities  

E-print Network

and study sources in German. Upper-level literary courses and special topics seminars both polish linguistic182 German and Slavic Studies The School of Humanities Chair Klaus Weissenberger Professors Peter Kreutzer Lecturer Dariusz Skorczewski Degrees Offered: B.A. in German Studies, B.A. in Slavic Studies

Richards-Kortum, Rebecca

251

German and Slavic Studies The School of Humanities  

E-print Network

184 German and Slavic Studies The School of Humanities Chair Uwe Steiner Professor Klaus, interdisciplinary study, and the role of German culture within the broad context of European history. Studies in film, cultural theory, and gender complement traditional studies of German literature, philosophy

Richards-Kortum, Rebecca

252

EPA'S HUMAN STUDIES FACILITY AT CHAPEL HILL (BROCHURE)  

EPA Science Inventory

EPA's Human Studies Facility is distiguished by unique, state-of-the art exposure systems designed for studing the health effects of airborne pollutants. The chambers can deliver most gaseous pollutants at precise concentrations and atmospheric conditions. Instrumentation enable...

253

NIH to Launch Human Safety Study of Ebola Vaccine Candidate  

MedlinePLUS

... EDT NIH to Launch Human Safety Study of Ebola Vaccine Candidate Trial is First in Series of ... expected in late 2014. Vesicular Stomatitis Virus (VSV) Ebola Vaccine Testing The NIH will also collaborate with ...

254

A multiple imputation approach to disclosure limitation for high-age individuals in longitudinal studies  

PubMed Central

Disclosure limitation is an important consideration in the release of public use data sets. It is particularly challenging for longitudinal data sets, since information about an individual accumulates with repeated measures over time. Research on disclosure limitation methods for longitudinal data has been very limited. We consider here problems created by high ages in cohort studies. Because of the risk of disclosure, ages of very old respondents can often not be released; in particular this is a specific stipulation of the Health Insurance Portability and Accountability Act (HIPAA) for the release of health data for individuals. Top-coding of individuals beyond a certain age is a standard way of dealing with this issue, and it may be adequate for cross-sectional data, when a modest number of cases are affected. However, this approach leads to serious loss of information in longitudinal studies when individuals have been followed for many years. We propose and evaluate an alternative to top-coding for this situation based on multiple imputation (MI). This MI method is applied to a survival analysis of simulated data, and data from the Charleston Heart Study (CHS), and is shown to work well in preserving the relationship between hazard and covariates. PMID:20552576

An, Di; Little, Roderick J.A.; McNally, James W.

2010-01-01

255

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

256

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

257

Space station human productivity study, volume 1  

NASA Technical Reports Server (NTRS)

The primary goal was to develop design and operations requirements for direct support of intra-vehicular activity (IVA) crew performance and productivity. It was recognized that much work had already been accomplished which provided sufficient data for the definition of the desired requirements. It was necessary, therefore, to assess the status of such data to extract definable requirements, and then to define the remaining study needs. The explicit objectives of the study were to: review existing data to identify potential problems of space station crew productivity and to define requirements for support of productivity insofar as they could be justified by current information; identify those areas that lack adequate data; and prepare plans for managing studies to develop the lacking data, so that results can be input to the space station program in a timely manner.

1985-01-01

258

Hispanic Studies The School of Humanities  

E-print Network

Spanish, which tests students' competence in Hispanic literature and linguistics · TakeSPAN507Teaching College and on Spanish linguistics. The department stresses linguistic competence, interdisciplinary study,art,cultural theory,translation,and gender.Freshman seminars are conducted in English and stress written and oral

Richards-Kortum, Rebecca

259

Religious Studies The School of Humanities  

E-print Network

,Africanreligion,Buddhism,comparativestudies,cross-culturalstudies, Islam, Hinduism, methodological studies, or ethics/philosophy of religion Honors Program. Qualified of religion) and religious traditions (African religions, Buddhism, Christianity, comparative religions, Hindu to Religion · 2 introductory courses in religious traditions (oneWestern;one non-Western) · At least 3 courses

Richards-Kortum, Rebecca

260

Study on current limiting characteristics of SFCL with two trigger current levels  

Microsoft Academic Search

In this paper, the superconducting fault current limiter (SFCL) with two trigger current levels was suggested and its effectiveness through the analysis on the current limiting characteristics was described. The proposed SFCL, which consists of the triggering and the limiting components, can limit the fault current by generating the limiting impedance through two steps according to the amplitude of the

S. H. Lim

2010-01-01

261

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

PubMed

This study aimed 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 25-86 years were included. Periodontal status was assessed by clinical attachment loss (CAL), probing depth and number of missing teeth. Lung function was measured using spirometry, body plethysmography and diffusing capacity of the lung for carbon monoxide. Linear regression models using fractional polynomials were used to assess associations between periodontal disease and lung function. Fibrinogen and high-sensitivity 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 of the lung for carbon monoxide. Associations were confirmed for mean probing depth, extent measures of CAL/probing depth and number of missing teeth. 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

2013-12-01

262

Studies on the tolerance limit of fluoride in food in China  

SciTech Connect

To estimate the appropriate tolerance limit of fluoride in food in China, fluoride-related endemic diseases, background levels of fluoride in foods, and daily total intake of fluoride per capita were studied in addition to the subchronic toxicity test of fluoride in rats. In the general population, the daily total intake of fluoride from food, water, and air is 1.45-3.15 mg per capita. On the basis of these results and other information, it is suggested that the ADI of fluoride in the Chinese population should be 3.5 mg per capita, or 0.058 mg/kg body wt, and the tolerance limit of fluoride should be 1.0 ppm in rice, wheat flour, vegetables, and freshwater fish.

Chen, S.L.; Gong, Y.J.; Fu, Y.G. (Zhejiang Academy of Medicine (China))

1988-10-01

263

Animal models are reliably mimicking human diseases? A morphological study that compares animal with human NAFLD.  

PubMed

Non-alcoholic fatty liver disease (NAFLD) is a clinical-pathological syndrome that includes a wide spectrum of morphological alterations. In research, animal models are crucial in evaluating not only the pathogenesis of NAFLD and its progression, but also the therapeutic effects of various agents. Investigations on the ultrastructural features of NAFLD in humans are not copious, due to the difficulty to obtain human samples and to the long time of NAFLD to evolve. Translational comparative studies on the reliability of animal models in representing the histopathologic picture as seen in humans are missing. To overcome this lack of investigations, we compared the ultrastructural NAFLD features of an animal model versus human. Sprague-Dawley rats were fed with a high fat diet (HFD) for 1-4 weeks, while control rats were fed with a standard diet. Human specimens were collected from patients with diagnosed fatty liver disease, undergoing liver biopsies or surgery. Rat and human samples were examined by light microscopy and by transmission and high resolution scanning electron microscopy. The present work demonstrated that NAFLD in animal model and in human, share overlapping ultrastructural features. In conclusion, animal HFD represent an appropriate tool in studying the pathogenesis of NAFLD. Microsc. Res. Tech. 77:790-796, 2014. © 2014 Wiley Periodicals, Inc. PMID:25044260

Solinas, Paola; Isola, Michela; Lilliu, Maria Alberta; Conti, Gabriele; Civolani, Alberto; Demelia, Luigi; Loy, Francesco; Isola, Raffaella

2014-10-01

264

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.

265

http://www.kyoto-u.ac.jp/ja Integrated Human Studies Integrated Human Studies  

E-print Network

Pharmaceutical Sciences Pharmacy ( ) Engineering Global Engineering, Architecture, Engineering Science and Management Science Science Medicine Medical Science ( ) Human Health Sciences Pharmaceutical Sciences, Electrical and Electronic Engineering, Informatics and Mathematical Science, Industrial Chemistry Agriculture

Takada, Shoji

266

Pig and guinea pig skin as surrogates for human in vitro penetration studies: a quantitative review.  

PubMed

Both human and animal skin in vitro models are used to predict percutaneous penetration in humans. The objective of this review is a quantitative comparison of permeability and lag time measurements between human and animal skin, including an evaluation of the intra and inter species variability. We limit our focus to domestic pig and rodent guinea pig skin as surrogates for human skin, and consider only studies in which both animal and human penetration of a given chemical were measured jointly in the same lab. When the in vitro permeability of pig and human skin were compared, the Pearson product moment correlation coefficient (r) was 0.88 (P<0.0001), with an intra species average coefficient of variation of skin permeability of 21% for pig and 35% for human, and an inter species average coefficient of variation of 37% for the set of studied compounds (n=41). The lag times of pig skin and human skin did not correlate (r=0.35, P=0.26). When the in vitro permeability of guinea pig and human skin were compared, r=0.96 (P<0.0001), with an average intra species coefficient of variation of 19% for guinea pig and 24% for human, and an inter species coefficient of variation of permeability of 41% for the set of studied compounds (n=15). Lag times of guinea pig and human skin correlated (r=0.90, P<0.0001, n=12). When permeability data was not reported a factor of difference (FOD) of animal to human skin was calculated for pig skin (n=50) and guinea pig skin (n=25). For pig skin, 80% of measurements fell within the range 0.3human skin permeability and have less variability than the human skin model. The skin model of choice will depend on the final purpose of the study and the compound under investigation. PMID:19013230

Barbero, Ana M; Frasch, H Frederick

2009-02-01

267

Human Studies of Angiogenic Gene Therapy  

PubMed Central

Despite significant advances in medical, interventional, and surgical therapy for coronary and peripheral arterial disease, the burden of these illnesses remains high. To address this unmet need, the science of therapeutic angiogenesis has been evolving for almost two decades. Early pre-clinical studies and phase I clinical trials achieved promising results with growth factors administered as recombinant proteins or as single-agent gene therapies, and data accumulated through 10 years of clinical trials indicate that gene therapy has an acceptable safety profile. However, more rigorous phase II and phase III clinical trials have failed to unequivocally demonstrate that angiogenic agents are beneficial under the conditions and in the patients studied to date. Investigators have worked to understand the biology of the vascular system and to incorporate their findings into new treatments for patients with ischemic disease. Recent gene- and cell-therapy trials have demonstrated the bioactivity of several new agents and treatment strategies. Collectively, these observations have renewed interest in the mechanisms of angiogenesis and deepened our understanding of the complexity of vascular regeneration. Gene therapy that incorporates multiple growth factors, approaches that combine cell and gene therapy, and the administration of "master switch" agents that activate numerous downstream pathways are among the credible and plausible steps forward. In this review, we will examine the clinical development of angiogenic therapy, summarize several of the lessons learned during the conduct of these trials, and suggest how this prior experience may guide the conduct of future preclinical investigations and clinical trials. PMID:19815827

Gupta, Rajesh; Tongers, Jörn; Losordo, Douglas W.

2009-01-01

268

Mammillotegmental tract in the human brain: diffusion tensor tractography study  

Microsoft Academic Search

Introduction  Several animal studies have been conducted for the identification of the mammillotegmental tract (MTT); however, no study\\u000a has been reported in the human brain.\\u000a \\u000a \\u000a \\u000a \\u000a Methods  In the current study, using diffusion tensor tractography (DTT), we attempted to identify the MTT in the human brain. We recruited\\u000a 31 healthy volunteers for this study. Diffusion tensor images were acquired using 1.5 T, and the

Hyeok Gyu Kwon; Ji Heon Hong; Sung Ho Jang

2011-01-01

269

Manifold learning for human population structure studies.  

PubMed

The dimension of the population genetics data produced by next-generation sequencing platforms is extremely high. However, the "intrinsic dimensionality" of sequence data, which determines the structure of populations, is much lower. This motivates us to use locally linear embedding (LLE) which projects high dimensional genomic data into low dimensional, neighborhood preserving embedding, as a general framework for population structure and historical inference. To facilitate application of the LLE to population genetic analysis, we systematically investigate several important properties of the LLE and reveal the connection between the LLE and principal component analysis (PCA). Identifying a set of markers and genomic regions which could be used for population structure analysis will provide invaluable information for population genetics and association studies. In addition to identifying the LLE-correlated or PCA-correlated structure informative marker, we have developed a new statistic that integrates genomic information content in a genomic region for collectively studying its association with the population structure and LASSO algorithm to search such regions across the genomes. We applied the developed methodologies to a low coverage pilot dataset in the 1000 Genomes Project and a PHASE III Mexico dataset of the HapMap. We observed that 25.1%, 44.9% and 21.4% of the common variants and 89.2%, 92.4% and 75.1% of the rare variants were the LLE-correlated markers in CEU, YRI and ASI, respectively. This showed that rare variants, which are often private to specific populations, have much higher power to identify population substructure than common variants. The preliminary results demonstrated that next generation sequencing offers a rich resources and LLE provide a powerful tool for population structure analysis. PMID:22272259

Siu, Hoicheong; Jin, Li; Xiong, Momiao

2012-01-01

270

Features of wild-type human SOD1 limit interactions with misfolded aggregates of mouse G86R Sod1  

PubMed Central

Mutations in the gene encoding superoxide dismutase 1 (SOD1) account for about 20% of the cases of familial amyotrophic lateral sclerosis (fALS). It is well established that mutations in SOD1, associated with fALS, heighten the propensity of the protein to misfold and aggregate. Although aggregation appears to be a factor in the toxicity of mutant SOD1s, the precise nature of this toxicity has not been elucidated. A number of other studies have now firmly established that raising the levels of wild-type (WT) human SOD1 (hSOD1) proteins can in some manner augment the toxicity of mutant hSOD1 proteins. However, a recent study demonstrated that raising the levels of WT-hSOD1 did not affect disease in mice that harbor a mouse Sod1 gene (mSod1) encoding a well characterized fALS mutation (G86R). In the present study, we sought a potential explanation for the differing effects with WT-hSOD1 on the toxicity of mutant hSOD1 versus mutant mSod1. In the cell culture models used here, we observe poor interactions between WT-hSOD1 and misfolded G86R-mSod1, possibly explaining why over-expression of WT-hSOD1 does not synergize with mutant mSod1 to accelerate the course of the disease in mice. PMID:24341866

2013-01-01

271

Are animal models useful for studying human disc disorders/degeneration?  

PubMed Central

Intervertebral disc (IVD) degeneration is an often investigated pathophysiological condition because of its implication in causing low back pain. As human material for such studies is difficult to obtain because of ethical and government regulatory restriction, animal tissue, organs and in vivo models have often been used for this purpose. However, there are many differences in cell population, tissue composition, disc and spine anatomy, development, physiology and mechanical properties, between animal species and human. Both naturally occurring and induced degenerative changes may differ significantly from those seen in humans. This paper reviews the many animal models developed for the study of IVD degeneration aetiopathogenesis and treatments thereof. In particular, the limitations and relevance of these models to the human condition are examined, and some general consensus guidelines are presented. Although animal models are invaluable to increase our understanding of disc biology, because of the differences between species, care must be taken when used to study human disc degeneration and much more effort is needed to facilitate research on human disc material. PMID:17632738

Eisenstein, Stephen M.; Ito, Keita; Little, Christopher; Kettler, A. Annette; Masuda, Koichi; Melrose, James; Ralphs, Jim; Stokes, Ian; Wilke, Hans Joachim

2007-01-01

272

Post-study caffeine administration enhances memory consolidation in humans.  

PubMed

It is currently not known whether caffeine has an enhancing effect on long-term memory in humans. We used post-study caffeine administration to test its effect on memory consolidation using a behavioral discrimination task. Caffeine enhanced performance 24 h after administration according to an inverted U-shaped dose-response curve; this effect was specific to consolidation and not retrieval. We conclude that caffeine enhanced consolidation of long-term memories in humans. PMID:24413697

Borota, Daniel; Murray, Elizabeth; Keceli, Gizem; Chang, Allen; Watabe, Joseph M; Ly, Maria; Toscano, John P; Yassa, Michael A

2014-02-01

273

A clinicopathological study of human yellow fever*  

PubMed Central

During an epidemic of yellow fever in the Jos Plateau area of Nigeria, 9 adult males with clinically diagnosed yellow fever were studied by haematological, biochemical, virological, serological, and liver biopsy methods. The ages of the patients ranged from 20 to 55 years and the duration of illness was 3-62 days. No virus was isolated from any patient but all patients should biochemical evidence of severe hepatocellular damage. Leucopenia was a feature of the late acute stage of the disease. Five sera had antibodies to yellow fever at titres greater than 1: 32, 3 of them being monospecific for yellow fever. The classical histological features of yellow fever were present only in the acute or late acute stages, when complement-fixation tests may be negative. With convalescence and the production of complement-fixing antibodies in high titres, the histological features resembled those of a persisting nonspecific hepatitis. In an endemic area, the histological features of yellow fever will depend on the stage of the disease and a picture of nonspecific hepatitis would not exclude yellow fever in the absence of confirmation from serological tests. ImagesFig. 1Fig. 2AFig. 2BFig. 3Fig. 4Fig. 5Fig. 6 PMID:4538039

Francis, T. I.; Moore, D. L.; Edington, G. M.; Smith, J. A.

1972-01-01

274

A clinicopathological study of human yellow fever.  

PubMed

During an epidemic of yellow fever in the Jos Plateau area of Nigeria, 9 adult males with clinically diagnosed yellow fever were studied by haematological, biochemical, virological, serological, and liver biopsy methods. The ages of the patients ranged from 20 to 55 years and the duration of illness was 3-62 days. No virus was isolated from any patient but all patients should biochemical evidence of severe hepatocellular damage. Leucopenia was a feature of the late acute stage of the disease. Five sera had antibodies to yellow fever at titres greater than 1: 32, 3 of them being monospecific for yellow fever. The classical histological features of yellow fever were present only in the acute or late acute stages, when complement-fixation tests may be negative. With convalescence and the production of complement-fixing antibodies in high titres, the histological features resembled those of a persisting nonspecific hepatitis. In an endemic area, the histological features of yellow fever will depend on the stage of the disease and a picture of nonspecific hepatitis would not exclude yellow fever in the absence of confirmation from serological tests. PMID:4538039

Francis, T I; Moore, D L; Edington, G M; Smith, J A

1972-01-01

275

Vestibular schwannoma and cell-phones. Results, limits and perspectives of clinical studies.  

PubMed

The widespread development of cell-phones entails novel user exposure to electromagnetic fields. Health impact is a public health issue and a source of anxiety in the population. Some clinical studies reported an association between cell and cordless phone use and vestibular schwannoma; others found none. A systematic review was performed of all published clinical studies (cohort, registry, case-control and validation studies), with analysis of results, to determine the nature of the association and the level of evidence. Cohort studies were inconclusive due to short exposure durations and poor representativeness. Registry studies showed no correlation between evolution of cell-phone use and incidence of vestibular schwannoma. Case-control studies reported contradictory results, with methodological flaws. Only a small number of subjects were included in long-term studies (>10 years), and these failed to demonstrate any indisputable causal relationship. Exposure assessment methods were debatable, and long-term assessment was lacking. An on-going prospective study should determine any major effect of electromagnetic fields; schwannoma being a rare pathology, absence of association will be difficult to prove. No clinical association has been demonstrated between cell and cordless phone use and vestibular schwannoma. Existing studies are limited by their retrospective assessment of exposure. PMID:23725662

Mornet, E; Kania, R; Sauvaget, E; Herman, P; Tran Ba Huy, P

2013-11-01

276

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. PMID:7043913

Fabrikant, J. I.

1981-01-01

277

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

SciTech Connect

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.

1982-08-01

278

[A study on decreasing the instrument detection limit of atomic fluorescence spectrometry (AFS-930) for Hg].  

PubMed

In the present study, the detection limit of atomic fluorescence spectrometry (AFS-930) was decreased to 2 ng x L(-1) (n=6) based on several optimizing modifications, including that the sub-high voltage of photomultiplier tube and the current of hollow-cathode lamp were elevated to 280 V and to 30 mA, respectively, and the height of atomization cell was set as 10 mm; In addition, the concentration of KBH4 was decreased to 0.5% (KOH 0.2%). With the optimized parameters, a good standard curve of Hg concentration versus intensity of fluorescence (If) could been obtained readily, after that, a 4-ng x L(-1)-Hg water samples was measured accurately with a little relative standard deviation (RSD) of <5%, while for approximately 2-ng x L(-1)-Hg waters the RSD varied within a wide range of 10.9%-27.2%, likely due to the absorption of Hg by polyethylene vessels used in this study and/or due to the contamination by analysis grade reagents used in this study. By using low-absorption polytetrafluoroethylene (PTFE) materials and the guaranteed reagents, the instrument detection limit was further decreased to 1 ng x L(-1) (n=10). PMID:19650507

Yin, Xue-bin; Lu, Xiao-qi; Yao, Chun-xia; Song, Jing; Qian, Wei; Luo, Yong-ming; Liang, You-qing; Sun, Li-guang

2009-05-01

279

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

280

Comparison of Storage Conditions for Human Vaginal Microbiome Studies  

PubMed Central

Background The effect of storage conditions on the microbiome and metabolite composition of human biological samples has not been thoroughly investigated as a potential source of bias. We evaluated the effect of two common storage conditions used in clinical trials on the bacterial and metabolite composition of the vaginal microbiota using pyrosequencing of barcoded 16S rRNA gene sequencing and 1H-NMR analyses. Methodology/Principal Findings Eight women were enrolled and four mid-vaginal swabs were collected by a physician from each woman. The samples were either processed immediately, stored at ?80°C for 4 weeks or at ?20°C for 1 week followed by transfer to ?80°C for another 4 weeks prior to analysis. Statistical methods, including Kolmogorovo-Smirnov and Wilcoxon tests, were performed to evaluate the differences in vaginal bacterial community composition and metabolites between samples stored under different conditions. The results showed that there were no significant differences between samples processed immediately after collection or stored for varying durations. 1H-NMR analysis of the small molecule metabolites in vaginal secretions indicated that high levels of lactic acid were associated with Lactobacillus-dominated communities. Relative abundance of lactic acid did not appear to correlate with relative abundance of individual Lactobacillus sp. in this limited sample, although lower levels of lactic acid were observed when L. gasseri was dominant, indicating differences in metabolic output of seemingly similar communities. Conclusions/Significance These findings benefit large-scale, field-based microbiome and metabolomic studies of the vaginal microbiota. PMID:22655031

Bai, Guoyun; Gajer, Pawel; Nandy, Melissa; Ma, Bing; Yang, Hongqiu; Sakamoto, Joyce; Blanchard, May H.; Ravel, Jacques; Brotman, Rebecca M.

2012-01-01

281

Experimental and analytical tools for studying the human microbiome.  

PubMed

The human microbiome substantially affects many aspects of human physiology, including metabolism, drug interactions and numerous diseases. This realization, coupled with ever-improving nucleotide sequencing technology, has precipitated the collection of diverse data sets that profile the microbiome. In the past 2 years, studies have begun to include sufficient numbers of subjects to provide the power to associate these microbiome features with clinical states using advanced algorithms, increasing the use of microbiome studies both individually and collectively. Here we discuss tools and strategies for microbiome studies, from primer selection to bioinformatics analysis. PMID:22179717

Kuczynski, Justin; Lauber, Christian L; Walters, William A; Parfrey, Laura Wegener; Clemente, José C; Gevers, Dirk; Knight, Rob

2012-01-01

282

Retinal electrophysiology for toxicology studies: applications and limits of ERG in animals and ex vivo recordings.  

PubMed

Assessing retinal drug toxicity is becoming increasingly important as different molecules are now developed for the treatment of neurodegenerative diseases and vascular disorders. In pharmacology and toxicology, the electroretinogram (ERG) and the multielectrode array (MEA) recording techniques can be used to quantify the possible side effects of retino-active xenobiotics. Toxicity testing requires the use of rodent as well as non-rodent models for extrapolation to the human model when determining risk and safety. Animal species differ in their retinal anatomo-physiology: most rodents used in toxicology studies are essentially nocturnal species, whereas the non-rodent laboratory species normally used (e.g. dogs, pigs and monkeys) are diurnal. The ratio between the photoreceptor populations which varies from species to species, should be considered when designing the experiment protocol and the interpretation. The described ERG procedures are designed to comply with all applicable good laboratory practice standards. Use of these procedures should yield an acceptable level of intra- and inter-subject variability for compiling a historical database, and for detecting possible retinal toxicity in animal studies. They could therefore be used as specific and standardized tools for screening of potential retinotoxic molecules in drug discovery and development in order to compare methods and results with those obtained in human electrophysiological assessments. Recording of ganglion cell light responses on ex vivo retina with the MEA technique can further demonstrate how retino-active xenobiotics affect retinal visual information processing by eliminating potential obstacles related to bioavailability and blood barrier permeability. PMID:18294830

Rosolen, Serge Georges; Kolomiets, Bogdan; Varela, Oscar; Picaud, Serge

2008-06-01

283

Potential Utility and Limitations of Thyroid Cancer Cell Lines as Models for Studying Thyroid Cancer  

PubMed Central

Background Tumor-derived cell lines are widely used to study the mechanisms involved in thyroid carcinogenesis but recent studies have reported redundancy among thyroid cancer cell lines and identification of some “thyroid cell lines” that are likely not of thyroid origin. Summary In this review, we have summarized the uses, the limitations, and the existing problems associated with the available follicular cell-derived thyroid cancer cell lines. There are some limitations to the use of cell lines as a model to “mimic” in vivo tumors. Based on the gene expression profiles of thyroid cell lines originating from tumors of different types it has become apparent that some of the cell lines are closely related to each other and to those of undifferentiated carcinomas. Further, many cell lines have lost the expression of thyroid-specific genes and have altered karyotypes, while they exhibit activation of several oncogenes (BRAF, v-raf murine sarcoma viral oncogene homolog B1; RAS, rat sarcoma; and RET/PTC, rearranged in transformation/papillary thyroid carcinoma) and inactivation of tumor suppressor gene (TP53) which is known to be important for thyroid tumorigenesis. Conclusions A careful selection of thyroid cancer cell lines that reflect the major characteristics of a particular type of thyroid cancer being investigated could be used as a good model system to analyze the signaling pathways that may be important in thyroid carcinogenesis. Further, the review of literature also suggests that some of the limitations can be overcome by using multiple cell lines derived from the same type of tumor. PMID:20001716

Pilli, Tania; Prasad, Kanteti V.; Jayarama, Shankar; Pacini, Furio

2009-01-01

284

Cryptosporidiosis in humans: Review of recent epidemiologic studies  

Microsoft Academic Search

Since 1976, when Cryptosporidium was first recognized as a human pathogen, understanding of the epidemiology of this protozoan parasite has increased substantially. This review discusses 14 recently published studies of the occurrence of cryptosporidiosis in developed and developing countries and compares their findings with those of previous epidemiologic reports. These studies show that cryptosporidiosis is an important public health problem

T. R. Navin

1985-01-01

285

An Experimental Study of the Emergence of Human Communication Systems  

Microsoft Academic Search

The emergence of human communication systems is typically investigated via 2 approaches with complementary strengths and weaknesses: naturalistic studies and computer simulations. This study was conducted with a method that combines these approaches. Pairs of participants played video games requiring communication. Members of a pair were physically separated but exchanged graphic signals through a medium that prevented the use of

Bruno Galantucci

2005-01-01

286

Faculty of Humanities and Social Sciences School of Education Studies  

E-print Network

/ICT and Education (5 Year Fixed Contract) The School of Education Studies seeks to appoint a highly applications from candidates who have experience in the fields of Digital Media /ICT and Education and whoFaculty of Humanities and Social Sciences School of Education Studies Lecturer in Digital Media

Humphrys, Mark

287

BA in AMERICAN STUDIES (570120) MAP Sheet College of Humanities  

E-print Network

BA in AMERICAN STUDIES (570120) MAP Sheet College of Humanities For students entering the degree Testament Doctrine and Covenants The Individual and Society Citizenship American Heritage Global & Cultural · Course substitutions may be made only with written, prior permission of the American Studies coordinator

Olsen Jr., Dan R.

288

BA in AMERICAN STUDIES (570120) Map Sheet College of Humanities  

E-print Network

BA in AMERICAN STUDIES (570120) Map Sheet College of Humanities For students entering the degree New Testament Doctrine and Covenants The Individual and Society Citizenship American Heritage Global choice · Course substitutions may be made only with written, prior permission of the American Studies

Martinez, Tony R.

289

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

2013-07-01

290

From Stockholm to Malawi: recent developments in studying human polyomaviruses.  

PubMed

Until a few years ago the polyomavirus family (Polyomaviridae) included a dozen viruses identified in avian and mammalian hosts. Two of these, the JC and BK-polyomaviruses isolated a long time ago, are known to infect humans and cause severe illness in immunocompromised hosts. Since 2007 an unprecedented number of eight novel polyomaviruses were discovered in humans. Among them are the KI- and WU-polyomaviruses identified in respiratory samples, the Merkel cell polyomavirus found in skin carcinomas and the polyomavirus associated with trichodysplasia spinulosa, a skin disease of transplant patients. Another four novel human polyomaviruses were identified, HPyV6, HPyV7, HPyV9 and the Malawi polyomavirus, so far not associated with any disease. In the same period several novel mammalian polyomaviruses were described. This review summarizes the recent developments in studying the novel human polyomaviruses, and touches upon several aspects of polyomavirus virology, pathogenicity, epidemiology and phylogeny. PMID:23255626

Feltkamp, Mariet C W; Kazem, Siamaque; van der Meijden, Els; Lauber, Chris; Gorbalenya, Alexander E

2013-03-01

291

Proc. INTERACT 2005, LNCS 3585, 767-780 RealTourist A Study of Augmenting Human-Human  

E-print Network

to contribute to an empirical foundation of future multimodal human-com- puter interaction systems with eyeProc. INTERACT 2005, LNCS 3585, 767-780 RealTourist A Study of Augmenting Human-Human and Human-Computer Dialogue with Eye-Gaze Overlay Pernilla Qvarfordt1 David Beymer2 Shumin Zhai2 1 Department of Computer

Zhai, Shumin

292

A basic study of Event-Related Potentials (ERPs) on human audiovisual spatial integration for human-machine interface  

Microsoft Academic Search

The technology of Human Machine Interface (HMI) mainly investigate about how to use machines in a more humanized way so that the communication between human and the machine could become more harmonic and natural. Previous studies indicate that there is an integration area in the human brain for audiovisual information processing. Although machines also possess mechanism for audiovisual processing, there

Yulin Gao; Jingjing Yang; Qi Li; Ryota Morikawa; Jinglong Wu

2010-01-01

293

Distribution limits of Batrachochytrium dendrobatidis: a case study in the Rocky Mountains, USA.  

PubMed

Knowledge of the environmental constraints on a pathogen is critical to predicting its dynamics and effects on populations. Batrachochytrium dendrobatidis (Bd), an aquatic fungus that has been linked with widespread amphibian declines, is ubiquitous in the Rocky Mountains. As part of assessing the distribution limits of Bd in our study area, we sampled the water column and sediments for Bd zoospores in 30 high-elevation water bodies that lacked amphibians. All water bodies were in areas where Bd has been documented from neighboring, lower-elevation areas. We targeted areas lacking amphibians because existence of Bd independent of amphibians would have both ecologic and management implications. We did not detect Bd, which supports the hypothesis that it does not live independently of amphibians. However, assuming a detection sensitivity of 59.5% (based on sampling of water where amphibians tested positive for Bd), we only had 95% confidence of detecting Bd if it was in > or =16% of our sites. Further investigation into potential abiotic reservoirs is needed, but our results provide a strategic step in determining the distributional and environmental limitations of Bd in our study region. PMID:19901397

Hossack, Blake R; Muths, Erin; Anderson, Chauncey W; Kirshtein, Julie D; Corn, Paul Stephen

2009-10-01

294

Distribution limits of Batrachochytrium dendrobatidis: a case study in the Rocky Mountains, USA.  

USGS Publications Warehouse

Knowledge of the environmental constraints on a pathogen is critical to predicting its dynamics and effects on populations. Batrachochytrium dendrobatidis (Bd), an aquatic fungus that has been linked with widespread amphibian declines, is ubiquitous in the Rocky Mountains. As part of assessing the distribution limits of Bd in our study area, we sampled the water column and sediments for Bd zoospores in 30 high-elevation water bodies that lacked amphibians. All water bodies were in areas where Bd has been documented from neighboring, lower-elevation areas. We targeted areas lacking amphibians because existence of Bd independent of amphibians would have both ecologic and management implications. We did not detect Bd, which supports the hypothesis that it does not live independently of amphibians. However, assuming a detection sensitivity of 59.5% (based on sampling of water where amphibians tested positive for Bd), we only had 95% confidence of detecting Bd if it was in > or =16% of our sites. Further investigation into potential abiotic reservoirs is needed, but our results provide a strategic step in determining the distributional and environmental limitations of Bd in our study region.

Hossack, B.R.; Muths, E.; Anderson, C.W.; Kirshtein, J.D.; Corn, P.S.

2009-01-01

295

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

296

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. PMID:23304360

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

297

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

2013-05-01

298

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. PMID:9866729

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

1998-01-01

299

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 âÂÂsystems viewâ 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.

300

To boil or not to boil -- A study of bubble embryo dormancy limits  

SciTech Connect

In the literature, particularly for refrigerants, experimental studies on the superheat required to initiate nucleate boiling tend to be widely scattered, not only among investigators but even for repeated tests by the same investigator. This study provides an explanation of why this occurs and how to avoid such scatter in future tests. With few exceptions, only re-entrant surface cavities are capable of containing dormant vapor bubble embryos. These dormant embryos are essential to initiate nucleate boiling from a cavity. The temperature (wall superheat) range over which an embryo is stable depends upon the cavity shape, neck size, and the fluid surface tension and thermal properties. Above the upper wall-superheat limit, nucleate boiling occurs. Below the lower limit, the embryo will quench (vanish) and cannot be reactivated by increasing the wall superheat. This study makes the following points, for a given cavity shape, fluid, and pressure (1) The larger the cavity neck radius, the smaller the wall-superheat range over which an embryo can exist. (2) Upon cooling any surface, the boiling cavity with the smallest neck radius will be the first to stop boiling but will require the greatest reduction in wall superheat to quench its embryo. (3) Each site that retains a (dormant) vapor embryo will resume boiling at the same wall-superheat at which it ceased boiling. (4) Small cavities can have a shape such that their vapor embryos will always exist, regardless of the wall temperature. Boiling can always be reinitiated from them. (5) Any wall subject to boiling has a memory. The greater the past wall-subcooling, the greater will be the wall-superheat required to initiate boiling. (6) The wall memory can be erased with sufficient wall-superheat and the presence of vapor.

Martin-Dominguez, I.R. [Inst. Politecnico Nacional-CIIDIR Unidad Durango, Durango City (Mexico); McDonald, T.W. [Univ. of Windsor, Ontario (Canada)

1997-12-31

301

Study of final state photons in hadronic Z 0 decay and limits on new phenomena  

NASA Astrophysics Data System (ADS)

The differential cross section for final state radiation from primary quarks is obtained from a study of isolated energetic photons produced in the reaction e + e -? Z 0?hadrons+?, as measured in the DELPHI detector at the CERN LEP collider. When combined with the measurement of the total hadronic width of the Z 0, the observed rate determines the electroweak coupling constants of up and down type quarks, i.e., v_{{1 3}}^2 + a_{{1 3}}^2 = 1.13 ± 0.29 and v_{{2 3}}2 + a_{{2 3}}^2 = 1.65 ± 043. No evidence is seen for additional photon production from anomalous decays of the Z 0 or from decays of new particles. This measurement leads to upper limits on the production cross section times branching fraction of (a) the Higgs boson in the reaction e + e -? Z 0? H +?, H?hadrons, (b) an excited quark, q *? q+?, and (c) the contribution of an anomalous decay of the Z 0 into a photon and hadrons. These limits, all at the 95% confidence level, vary from 3 to 10pb as the mass of the intermediate state ( H, q * or Z *) varies from 10 GeV/c2 to 80 GeV/c2.

Abreu, P.; Adam, W.; Adami, F.; Adye, T.; Akesson, T.; Alekseev, G. D.; Allen, P.; Almehed, S.; Alvsvaag, S. J.; Amaldi, U.; Anassontzis, E.; Antilogus, P.; Apel, W.-D.; Apsimon, R. J.; Åsman, B.; Astier, P.; Augustin, J.-E.; Augustinus, A.; Baillon, P.; Bambade, P.; Barao, F.; Barate, R.; Barbiellini, G.; Bardin, D. Y.; Baroncelli, A.; Barring, O.; Bartl, W.; Bates, M. J.; Battaglia, M.; Baubillier, M.; Becks, K.-H.; Beeston, C. J.; Begalli, M.; Beilliere, P.; Belokopytov, Yu.; Beltran, P.; Benedic, D.; Benlloch, J. M.; Berggren, M.; Bertrand, D.; Bianchi, F.; Bilenky, M. S.; Billoir, P.; Bjarne, J.; Bloch, D.; Blyth, S.; Bocci, V.; Bogolubov, P. N.; Bolognese, T.; Bonapart, M.; Bonesini, M.; Bonivento, W.; Booth, P. S. L.; Boratav, M.; Borgeaud, P.; Borisov, G.; Borner, H.; Bosio, C.; Bostjancic, B.; Botner, O.; Bouquet, B.; Bozzo, M.; Braibant, S.; Branchini, P.; Brand, K. D.; Brenner, R. A.; Bricman, C.; Brown, R. C. A.; Brummer, N.; Brunet, J.-M.; Bugge, L.; Buran, T.; Burmeister, H.; Buytaert, J. A. M. A.; Caccia, M.; Calvi, M.; Camacho Rozas, A. J.; Campion, A.; Camporesi, T.; Canale, V.; Cao, F.; Carena, F.; Carroll, L.; Caso, C.; Castelli, E.; Castillo Gimenez, M. V.; Cattai, A.; Cavallo, F. R.; Cerrito, L.; Chan, A.; Chapkin, M.; Charpentier, P.; Checchia, P.; Chelkov, G. A.; Chevalier, L.; Chliapnikov, P.; Chorowicz, V.; Cirio, R.; Clara, M. P.; Collins, P.; Contreras, J. L.; Contri, R.; Cosme, G.; Couchot, F.; Crawley, H. B.; Crennell, D.; Crosetti, G.; Crozon, M.; Cuevas Maestro, J.; Czellar, S.; Dagoret, S.; Dahl-Jensen, E.; Dalmagne, B.; Dam, M.; Damgaard, G.; Darbo, G.; Daubie, E.; Dauncey, P. D.; Davenport, M.; David, P.; de Angelis, A.; de Beer, M.; de Boeck, H.; de Boer, W.; de Clercq, C.; de Fez Laso, M. D. M.; de Groot, N.; de La Vaissiere, C.; de Lotto, B.; de Min, A.; Defoix, C.; Delikaris, D.; Delorme, S.; Delpierre, P.; Demaria, N.; di Ciaccio, L.; Dijkstra, H.; Djama, F.; Dolbeau, J.; Doll, O.; Donszelmann, M.; Doroba, K.; Dracos, M.; Drees, J.; Dris, M.; Dufour, Y.; Dulinski, W.; Eek, L.-O.; Eerola, P. A.-M.; Ekelof, T.; Ekspong, G.; Elliot Peisert, A.; Engel, J.-P.; Fassouliotis, D.; Feindt, M.; Fernandez Alonso, M.; Ferrer, A.; Filippas, T. A.; Firestone, A.; Foeth, H.; Fokitis, E.; Folegati, P.; Fontanelli, F.; Forbes, K. A. J.; Forsbach, H.; Franek, B.; Frenkiel, P.; Fries, D. C.; Frodesen, A. G.; Fruhwirth, R.; Fulda-Quenzer, F.; Furnival, K.; Furstenau, H.; Fuster, J.; Galeazzi, G.; Gamba, D.; Garcia, C.; Garcia, J.; Gaspar, C.; Gasparini, U.; Gavillet, P.; Gazis, E. N.; Gerber, J.-P.; Giacomelli, P.; Glitza, K.-W.; Gokieli, R.; Golovatyuk, V. M.; Gomez Y Cadenas, J. J.; Goobar, A.; Gopal, G.; Gorski, M.; Gracco, V.; Grant, A.; Grard, F.; Graziani, E.; Gros, M.-H.; Grosdidier, G.; Gross, E.; Grossetete, B.; Grosse-Wiesmann, P.; Guy, J.; Hahn, F.; Hahn, M.; Haider, S.; Hajduk, Z.; Hakansson, A.; Hallgren, A.; Hamacher, K.; Hamel de Monchenault, G.; Harris, F. J.; Heck, B. W.; Henkes, T.; Herbst, I.; Hernandez, J. J.; Herquet, P.; Herr, H.; Hietanen, I.; Higgins, C. O.; Higon, E.; Hilke, H. J.; Hodgson, S. D.; Hofmokl, T.; Holmes, R.; Holmgren, S.-O.; Holthuizen, D.; Honore, P. F.; Hooper, J. E.; Houlden, M.; Hrubec, J.; Hulth, P. O.; Hultqvist, K.; Husson, D.; Ioannou, P.; Isenhower, D.; Iversen, P.-S.; Jackson, J. N.; Jalocha, P.; Jarlskog, G.; Jarry, P.; Jean-Marie, B.; Johansson, E. K.; Johnson, D.; Jonker, M.; Jonsson, L.; Juillot, P.; Kalkanis, G.; Kalmus, G.; Kapusta, F.; Katsanevas, S.; Katsoufis, E. C.; Keranen, R.; Kesteman, J.; Khomenko, B. A.; Khovanski, N. N.; King, B.; Kjaer, N. J.; Klein, H.; Klempt, W.; Klovning, A.; Kluit, P.; Koch-Mehrin, A.; Koehne, J. H.; Koene, B.; Kokkinias, P.; Kopf, M.; Koratzinos, M.; Korcyl, K.; Korytov, A. V.; Kostukhin, V.; Kourkoumelis, C.; Kreuzberger, T.; Krolikowski, J.; Kronkvist, I.; Krstic, J.; Kruener-Marquis, U.; Krupinski, W.; Kucewicz, W.; Kurvinen, K.; Lacasta, C.; Lambropoulos, C.; Lamsa, J. W.; Lanceri, L.; Lapin, V.; Laugier, J.-P.; Lauhakangas, R.; Leder, G.; Ledroit, F.; Leitner, R.; Lemoigne, Y.; Lemonne, J.; Lenzen, G.; Lepeltier, V.; Letessier-Selvon, A.; Liko, D.; Lieb, E.; Lillethun, E.; Lindgren, J.; Lipniacka, A.; Lippi, I.; Llosa, R.; Loerstad, B.; Lokajicek, M.; Loken, J. G.; Lopez Aguera, M. A.; Lopez-Fernandez, A.; Los, M.; Loukas, D.; Lounis, A.; Lozano, J. J.; Lucock, R.; Lutz, P.; Lyons, L.; Maehlum, G.; Magnussen, N.; Maillard, J.; Maltezos, A.; Mandl, F.; Marco, J.; Margoni, M.; Marin, J.-C.; Markou, A.; Marti, S.; Mathis, L.; Matorras, F.; Matteuzzi, C.; Matthiae, G.; Mazzucato, M.; McCubbin, M.; McKay, R.; McNulty, R.; Menichetti, E.; Meola, G.; Meroni, C.; Meyer, W. T.; Michelotto, M.; Mitaroff, W. A.; Mitselmakher, G. V.; Mjoernmark, U.; Moa, T.; Moeller, R.; Moenig, K.

1992-12-01

302

Epithelial Cell Coculture Models for Studying Infectious Diseases: Benefits and Limitations  

PubMed Central

Countless in vitro cell culture models based on the use of epithelial cell types of single lineages have been characterized and have provided insight into the mechanisms of infection for various microbial pathogens. Diverse culture models based on disease-relevant mucosal epithelial cell types derived from gastrointestinal, genitourinary, and pulmonary organ systems have delineated many key host-pathogen interactions that underlie viral, parasitic, and bacterial disease pathogenesis. An alternative to single lineage epithelial cell monoculture, which offers more flexibility and can overcome some of the limitations of epithelial cell culture models based on only single cell types, is coculture of epithelial cells with other host cell types. Various coculture models have been described, which incorporate epithelial cell types in culture combination with a wide range of other cell types including neutrophils, eosinophils, monocytes, and lymphocytes. This paper will summarize current models of epithelial cell coculture and will discuss the benefits and limitations of epithelial cell coculture for studying host-pathogen dynamics in infectious diseases. PMID:22007147

Duell, Benjamin L.; Cripps, Allan W.; Schembri, Mark A.; Ulett, Glen C.

2011-01-01

303

Human parainfluenza type 3 virus impairs the efficacy of glucocorticoids to limit allergy-induced pulmonary inflammation in guinea-pigs.  

PubMed

Viral exacerbations of allergen-induced pulmonary inflammation in pre-clinical models reportedly reduce the efficacy of glucocorticoids to limit pulmonary inflammation and airways hyper-responsiveness to inhaled spasmogens. However, exacerbations of airway obstruction induced by allergen challenge have not yet been studied. hPIV-3 (human parainfluenza type 3 virus) inoculation of guinea-pigs increased inflammatory cell counts in BAL (bronchoalveolar lavage) fluid and caused hyper-responsiveness to inhaled histamine. Both responses were abolished by treatment with either dexamethasone (20 mg/kg of body weight, subcutaneous, once a day) or fluticasone propionate (a 0.5 mg/ml solution aerosolized and inhaled over 15 min, twice a day). In ovalbumin-sensitized guinea-pigs, allergen (ovalbumin) challenge caused two phases of airway obstruction [measured as changes in sGaw (specific airways conductance) using whole body plethysmography]: an immediate phase lasting between 4 and 6 h and a late phase at about 7 h. The late phase, airway hyper-responsiveness to histamine and inflammatory cell counts in BAL were all significantly reduced by either glucocorticoid. Inoculation of guinea-pigs sensitized to ovalbumin with hPIV-3 transformed the allergen-induced airway obstruction from two transient phases into a single sustained response lasting up to 12 h. This exacerbated airway obstruction and airway hyper-responsiveness to histamine were unaffected by treatment with either glucocorticoid whereas inflammatory cell counts in BAL were only partially inhibited. Virus- or allergen-induced pulmonary inflammation, individually, are glucocorticoid-sensitive, but in combination generate a phenotype where glucocorticoid efficacy is impaired. This suggests that during respiratory virus infection, glucocorticoids might be less effective in limiting pulmonary inflammation associated with asthma. PMID:23678868

Ford, William R; Blair, Alan E; Evans, Rhys L; John, Elinor; Bugert, Joachim J; Broadley, Kenneth J; Kidd, Emma J

2013-11-01

304

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

305

Use of primary cultures of human hepatocytes in toxicology studies.  

PubMed

Often results from toxicological studies using rodent models cannot be directly extrapolated to probable effects in human beings. In order to examine the genotoxic potential of chemicals in human liver cells, a human hepatocyte DNA repair assay has been defined. Procedures were optimized to prepare primary cultures of human hepatocytes from discarded surgical material. On eight different occasions human hepatocyte cultures of sufficient viability to measure DNA repair were successfully prepared by collagenase perfusion techniques. The cells were allowed to attach to plastic or collagen substrata for periods of 1.5 to 24 h and subsequently incubated with [3H]thymidine and test chemicals for periods of 18 to 24 h. Chemically induced DNA repair, measured as unscheduled DNA synthesis, was quantitated autoradiographically. The following compounds were tested: 2-acetylaminofluorene, aflatoxin B1, 2-aminobenzyl alcohol, aniline, benzo(a)pyrene, carbon tetrachloride, chloroform, 2,4-diaminotoluene, 2,6-diaminotoluene, di(2-ethylhexyl)phthalate, dimethylnitrosamine, 1,6-dinitropyrene, 2,4-dinitrotoluene, 2,6-dinitrotoluene, methyl chloride, 5-methylchrysene, mono(2-ethylhexyl)phthalate, 2-methyl-2-P-(1,2,3,4-tetrahydro-1-naphthyl)phenoxypropionic acid (nafenopin), beta-naphthylamine, nitrobenzene, 2-nitrobenzyl alcohol, 2-nitrotoluene, 2,3,7,8-tetrachlorodibenzo-p-dioxin, unleaded gasoline, and 4-chloro-6-(2,3-xylidino)-2-pyrimidinylthioacetic acid (Wy-14,643). In only one of eight cases did some of the chemicals generally regarded as genotoxic fail to give a positive response. For purposes of comparison, all test chemicals were evaluated in the in vitro rat hepatocyte DNA repair assay. Individual-to-individual variation in the DNA repair response was far greater for the human cultures than for cultures derived from rats. For only three chemicals was there a qualitative difference in the response between the rodent and the human cells; beta-naphthylamine was positive in the rat but in none of the human cultures examined, whereas the opposite was seen for 2,6-diaminotoluene and 5-methylchrysene. Clofibric acid, mono(2-ethylhexyl)phthalate, and Wy-14,643 induced enzymes indicative of peroxisomal proliferation in primary rat hepatocyte cultures, but not in two human hepatocyte cultures. These results indicate that, in general, the in vitro rat hepatocyte DNA repair assay is a valid model for predicting potential genotoxic effects in human beings. However, rodent hepatocytes may not be appropriate for assessing the potential of chemicals to elicit nongenotoxic effects in human beings such as the induction of hepatocyte peroxisomal proliferation. PMID:2917345

Butterworth, B E; Smith-Oliver, T; Earle, L; Loury, D J; White, R D; Doolittle, D J; Working, P K; Cattley, R C; Jirtle, R; Michalopoulos, G

1989-03-01

306

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

NASA Astrophysics Data System (ADS)

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 their current concentration in the temperate regions of Europe and the United States into the tropical regions of South America, Southeast Asia, and India. In order to predict future carbon budgets, it is necessary to quantify the impact of nitrogen on NPP. Currently there is no synthesis of ecosystem scale experiments that evaluates responses among biomes and across environmental gradients. The aim of this investigation is to test the prediction that nitrogen limitation is widespread, and to evaluate global patterns of NPP response to nitrogen. The present study compiles results from field-based nitrogen addition experiments in a comprehensive meta-analysis. Published studies were obtained through key word searches and referenced articles. A response metric was derived from each study based on measurements of plant growth under ambient nitrogen deposition (control) and experimental nitrogen addition (treatment). This metric is the response ratio (R): the ratio of mean growth in treatment divided by control plots. Therefore, a positive effect of nitrogen results in R>1. A meta-analysis was performed on ln(R) weighted by within-study variance. We found that most ecosystems are nitrogen limited (P<0.0001) and that average growth response to nitrogen was 32%. However, response was not uniform across biomes. Significant responses were observed in grasslands and forests (P<0.0001), but not wetlands and tundra (P=0.08 and P=0.16). While mean annual precipitation (MAP) was significantly correlated to R overall (P<0.0001), the direction of the effect varied among biomes. Correlations between R and MAP were positive for forest and tundra R (P=0.033 and P=0.0005) and negative for wetlands and grassland R (P=0.0018 and P<0.0001). Tundra and grassland R was also correlated to mean annual temperature (P=0.0002 and P=0.0009). Background nitrogen deposition was negatively correlated to R overall (P<0.0001) and within forests and wetlands (P=0.0007 and P=0.0002). These results suggest a strong interaction between the global nitrogen and carbon cycles, and support previous efforts to model the stimulation of NPP by nitrogen at the global scale. These results also indicate the importance of climate and biome type in mediating this response. The negative correlation between background deposition and R suggests that the strength of nitrogen limitation will decrease with increasing anthropogenic inputs.

Lebauer, D. S.; Treseder, K. K.

2006-12-01

307

Understanding the limits of Marxist approaches to sociocultural studies of science education  

NASA Astrophysics Data System (ADS)

In the first three sections of this paper we comment on some of the ideas developed in the forum papers, pointing out possible misunderstandings and constructing new explanations that clarify arguments we made in the original article. In the last section we expand the discussion raised in the original paper, elaborating on the limits of the use of Marxist approaches to sociocultural studies of science education. Following insights suggested by Loxley et al. (Cult Stud Sci Edu. doi: 10.1007/s11422-013-9554-z, 2013) and detailed by Zuss (Cult Stud Sci Edu, 2014) on the commodification of knowledge, we sketch an analysis of how knowledge is transformed into capital to understand why contemporary scholars are likely to be engaged in a relation of production that resembles capitalist exploitation.

Lima Junior, Paulo; Ostermann, Fernanda; Rezende, Flavia

2014-09-01

308

Stratosphere and troposphere (S-T) studies at Millstone Hill. Recent results, capabilities and limitations  

NASA Technical Reports Server (NTRS)

The 440-MHz incoherent-scatter radar at Millstone Hill has been used in recent years for studies of the troposphere and lower stratosphere with a fully steerable 150' antenna. The configuration of the radar system is briefly outlined. Clear-air returns are received over an altitude range 4 to 25 km. The power spectra of these returns can be measured with a range resolution of up to 300 m and a Doppler resolution of up to 4 cm/sec. Due to the lack of a natural shield around the radar, the ground clutter at Millstone is more severe than at other installations. With the use of a fine Doppler resolution, however, the atmospheric returns are readily discriminated from the clutter. Observations of turbulence structures, spatial inhomogeneity of turbulence, and enhanced turbulence associated with convective phenomena are described. Capabilities and limitations of the Millstone S-T radar are pointed out.

Rastogi, P. K.

1983-01-01

309

Nonperturbative Study of the {dollar}O{dollar}(4) Limit of the Standard Model.  

NASA Astrophysics Data System (ADS)

The renormalizability of the standard electroweak model is studied in the limit of the perturbative SU (2) gauge coupling and light fermions. A large scale Monte Carlo simulation demonstrated that the one Higgs doublet model is trivial in the infinite cut-off limit. We present evidences that the Higgs sector with O(4) symmetry is defined around a Gaussian fixed point at all bare coupling values. The scaling behavior and other properties of the model are studied in detail around the critical line in both symmetric and broken phases. We show that with a finite cut-off the O(4) model can be used as a low energy effective theory with finite coupling constant and mass generation from spontaneous symmetry breaking. The triviality argument for an upper bound on the Higgs mass is made quantitative under lattice regularization. The triviality bound is found numerically and an upper bound on the Higgs mass m_ {H} ~ 640GeV is read off at lattice dimensionless correlation length xi = 2. The constraint effective potential is used to obtain the renormalized coupling constant, to help with the finite size effects analysis and to check various renormalized perturbation relations. New Monte Carlo simulation algorithms are developed to calculate the constraint effective potential. We show that the O(4) model remains perturbative at all bare coupling values whenever the lattice correlation length xi >=q 1. Our finding sharpens the "No-Lose Corollary" for the Superconducting Super Collider (SSC) in the sense that the Standard Model will unlikely become strongly interacting. If we do not find a Higgs particle below 640GeV we probably will see new physics that can not be described by the Higgs sector of the Standard Model at SSC energy scale.

Shen, Yue

310

The Watershed as A Conceptual Framework for the Study of Environmental and Human Health  

PubMed Central

The watershed provides a physical basis for establishing linkages between aquatic contaminants, environmental health and human health. Current attempts to establish such linkages are limited by environmental and epidemiological constraints. Environmental limitations include difficulties in characterizing the temporal and spatial dynamics of agricultural runoff, in fully understanding the degradation and metabolism of these compounds in the environment, and in understanding complex mixtures. Epidemiological limitations include difficulties associated with the organization of risk factor data and uncertainty about which measurable endpoints are most appropriate for an agricultural setting. Nevertheless, it is our contention that an adoption of the watershed concept can alleviate some of these difficulties. From an environmental perspective, the watershed concept helps identify differences in land use and application of agrichemicals at a level of resolution relevant to human health outcomes. From an epidemiological perspective, the watershed concept places data into a construct with environmental relevance. In this perspectives paper, we discuss how the watershed can provide a conceptual framework for studies in environmental and human health. PMID:20508751

Kolok, Alan S.; Beseler, Cheryl L.; Chen, Xun-Hong; Shea, Patrick J.

2009-01-01

311

ORD BEST PRACTICES FOR OBSERVATIONAL HUMAN EXPOSURE MEASUREMENT STUDIES  

EPA Science Inventory

This abstract describes a presentation for the 2007 Society of Toxicology Annual Meeting in Charlotte, NC on March 27, 2007. It will be included in a special Issues Session titled "Scientific and Ethical Considerations in Human Exposure Studies." The presentation desc...

312

Preparing Global Citizens through the Study of Human Rights  

ERIC Educational Resources Information Center

The preparation of students for global citizenship represents a central challenge to social studies educators in the twenty-first century. Two-thirds of the world's poor are steeped in abject poverty and its grim consequences. The world refugee problem has reached staggering proportions. There is an international epidemic of human trafficking, and…

Kirkwood-Tucker, Toni Fuss

2012-01-01

313

Suelo: Human-assisted Sensing for Exploratory Soil Monitoring Studies  

E-print Network

Suelo: Human-assisted Sensing for Exploratory Soil Monitoring Studies Nithya Ramanathan Thomas required to fully un- derstand them. In this paper, we present Suelo, an embed- ded networked sensing system designed for soil monitoring. An important challenge for Suelo is that many soil sensors

Kohler, Eddie

314

Faculty of Humanities and Social Sciences SCHOOL OF EDUCATION STUDIES  

E-print Network

, the impact of new communities on Irish Education Systems, Entrepreneurship, Interculturalism in Education for Guidance in Education, the Commission on the Points System, the European Union 6th Framework, AgeFaculty of Humanities and Social Sciences SCHOOL OF EDUCATION STUDIES Lecturer in Education

Humphrys, Mark

315

Mass Media Studies and the Humanities: An Interdisciplinary Experiment.  

ERIC Educational Resources Information Center

This report on a curriculum project incorporating the study of the humanities and mass media is presented in four chapters. The first chapter is an overview and describes the three components of the curriculum project: (1) a new course entitled "Television as Popular Culture," (2) a team-taught course on media theory entitled "The Electric Media,"…

Marsden, Michael T.; And Others

316

A Factor Analytic Study of Attitudes toward Human Fertility  

ERIC Educational Resources Information Center

The study focuses on the development and partial validation of scales measuring a complex of attitudes toward human fertility. Attitudes were collected from a 270-item questionnaire and factor, multiple regression, and correlation analyses of the collected data were conducted. Inferences for the development of a population education curriculum are…

Gaughran, Edward; And Others

1976-01-01

317

MAJOR: HUMAN DEVELOPMENT & FAMILY STUDIES (HDFS) EMPHASIS: CHILD LIFE  

E-print Network

MAJOR: HUMAN DEVELOPMENT & FAMILY STUDIES (HDFS) EMPHASIS: CHILD LIFE Minimum HDFS-CL Major Hours complicated prerequisite structure. Meet with advisor to ensure successful completion of required course work prerequisites: 1- FCS 2610 Understanding Children: Behavior & Guidance 2- FCS 2620 Child Development Practicum

Tipple, Brett

318

Study of diaphyseal nutrient foramina in human long bones  

Microsoft Academic Search

A study was done to determine the number, size, direction, exact site and position of the nutrient foramina in human long bones. The position of all nutrient foramina observed was on the flexor aspect and was more or less around a fixed area, but the exact spot varied considerably. Two foramina were much more frequent in the femur, clavicle and

G. S. Longia; M. L. Ajmani; S. K. Saxena; R. J. Thomas

1980-01-01

319

Sociology--the scientific study of society and human  

E-print Network

SOCIOLOGY Sociology--the scientific study of society and human interaction--is an opportunity to learn a great deal about yourself and the society around you. The Department of Sociology at Wichita. As a sociology major, you are required to take research methods, statistics and theory, plus 15 hours

320

Studying Relationships Between Human Gaze, Description, and Computer Vision  

E-print Network

). symbiotic relationship might be exploited to better analyze and index content that people find importantStudying Relationships Between Human Gaze, Description, and Computer Vision Kiwon Yun1 , Yifan Peng the relationship be- tween images, the eye movements people make while view- ing images, and how people construct

Berg, Tamara L.

321

Innovation and human resource management fit: an empirical study  

Microsoft Academic Search

Purpose – This study aims to analyse the relationship between innovation and human resource management (HRM) from an empirical perspective, attempting to establish whether innovation determines the firm's HRM or conversely HRM influences the innovation level of the company Design\\/methodology\\/approach – Literature is reviewed from both theoretical and empirical perspectives. On the basis of this review, some research hypotheses are

Daniel Jiménez-Jiménez; Raquel Sanz-Valle

2005-01-01

322

The Dating Game A Case Study in Human Evolution  

NSDL National Science Digital Library

In this role-playing case study, students attempt to determine the identity of a variety of human fossils based on characteristics described during a “quiz show.”  The case was designed to be used in a general biology class for freshman students where the focus is on evolution. It could also be used in an anthropology or paleontology course.

Tobias, Shoshana; Herreid, Clyde F.

1999-01-01

323

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

NASA Astrophysics Data System (ADS)

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 for a European participation in human exploration and to estimate their influence on the Life Sciences and Life Support requirements; (ii) for selected mission scenarios, to critically assess the limiting factors for human health, wellbeing, and performance and to recommend relevant countermeasures; (iii) for selected mission scenarios, to critically assess the potential of Advanced Life Support Developments and to propose a European strategy including terrestrial applications; (iv) to critically assess the feasibility of existing facilities and technologies on ground and in space as testbeds in preparation for human exploratory missions and to develop a test plan for ground and ISS campaigns; (v) to develop a roadmap for a future European strategy towards human exploratory missions, including preparatory activities and terrestrial applications and benefits. A lunar base at the south pole where constant sunlight and potential water ice deposits could be assumed was selected as the moon scenario. the impact on human health, performance and well being has been investigated from the view point of the effects of microgravity (during space travel), reduced gravity (on the Moon) and abrupt gravity changes (during launch and landing), of the effects of cosmic radiation including solar particle events, of psychological issues as well as general health care. Countermeasures as well as necessary research using ground- based testbeds and/or the ISS have been defined. The need for highly intelligent autonomous diagnostic and therapy systems was considered as a driver also for terrestrial applications. Likewise advanced life support systems with a high degree of autonomy and regenerative capacity and synergy effects were considered where bioregenerative life support systems and biodiagnistic systems become essential especially for the long-term Mars scenario. A roadmap for a future European strategy leading to a potential European participation in a cooperative human exploratory mission, either to the Moon or to Mars, was produced. Ref. Horneck et al. HUMEX, study on the Survivability and Adaptation of Humans to Long-Duration Exploratory Missions, ESA SP (in press)

Horneck, G.

324

Animal-free toxicology: the use of human tissue to replace the use of animals - examples from human biomonitoring and human placental transport studies.  

PubMed

Human data on exposure and adverse effects are the most appropriate for human risk assessment, and modern toxicology focuses on human pathway analysis and the development of human biomarkers. Human biomonitoring and human placental transport studies provide necessary information for human risk assessment, in accordance with the legislation on chemical, medicine and food safety. Toxicology studies based on human mechanistic and exposure information can replace animal studies. These animal-free approaches can be further supplemented by new in silico methods and chemical structure-activity relationships. The inclusion of replacement expertise in the international Three Rs centres, the ongoing exploration of alternatives to animal research, and the improvement of conditions for research animals, all imply the beginning of a paradigm shift in toxicology research toward the use of human data. PMID:24512227

Knudsen, Lisbeth E

2013-12-01

325

Hairless mouse skin is limited as a model for assessing the effects of penetration enhancers in human skin.  

PubMed

The permeability coefficient of 5-fluorouracil through human abdominal and hairless mouse skins was used as an indicator of the relative effects of 12-h pretreatment of the skins with either penetration-enhancer mixtures [including laurocapram (Azone), decylmethylsulfoxide, oleic acid, and propylene glycol] or saline (control). After treatment with saline, fluxes of 5-fluorouracil through the two skin types were similar, but the mouse skin showed exaggerated responses to all the penetration-enhancer formulations. There was no consistent relationship between enchancer effects on the two skin types, and we conclude that the hairless mouse model should not be used to predict the effects of penetration enhancers in human skin. After treatment with saline, hairless mouse skin sharply increased in permeability after approximately 50 h hydration, suggesting that the stratum corneum had started to disrupt, whereas the flux through human skin remained unchanged. PMID:3373011

Bond, J R; Barry, B W

1988-06-01

326

Comparison of methods for imputing limited-range variables: a simulation study  

PubMed Central

Background Multiple imputation (MI) was developed as a method to enable valid inferences to be obtained in the presence of missing data rather than to re-create the missing values. Within the applied setting, it remains unclear how important it is that imputed values should be plausible for individual observations. One variable type for which MI may lead to implausible values is a limited-range variable, where imputed values may fall outside the observable range. The aim of this work was to compare methods for imputing limited-range variables, with a focus on those that restrict the range of the imputed values. Methods Using data from a study of adolescent health, we consider three variables based on responses to the General Health Questionnaire (GHQ), a tool for detecting minor psychiatric illness. These variables, based on different scoring methods for the GHQ, resulted in three continuous distributions with mild, moderate and severe positive skewness. In an otherwise complete dataset, we set 33% of the GHQ observations to missing completely at random or missing at random; repeating this process to create 1000 datasets with incomplete data for each scenario. For each dataset, we imputed values on the raw scale and following a zero-skewness log transformation using: univariate regression with no rounding; post-imputation rounding; truncated normal regression; and predictive mean matching. We estimated the marginal mean of the GHQ and the association between the GHQ and a fully observed binary outcome, comparing the results with complete data statistics. Results Imputation with no rounding performed well when applied to data on the raw scale. Post-imputation rounding and imputation using truncated normal regression produced higher marginal means than the complete data estimate when data had a moderate or severe skew, and this was associated with under-coverage of the complete data estimate. Predictive mean matching also produced under-coverage of the complete data estimate. For the estimate of association, all methods produced similar estimates to the complete data. Conclusions For data with a limited range, multiple imputation using techniques that restrict the range of imputed values can result in biased estimates for the marginal mean when data are highly skewed. PMID:24766825

2014-01-01

327

Excretion study of the ? 2-agonist reproterol in human urine  

Microsoft Academic Search

An excretion study of the ?2-agonist 7-[3-[(?-3,5-trihydroxyphenethyl)amino]-propyl]theophylline (reproterol) in human urine, which is reportedly misused by athletes and horses as a doping agent, is presented. The study was performed after an oral administration of 20 mg of reproterol hydrochloride. The collected urine samples were prepared using the standard anabolic steroid extraction procedure and analyzed by gas chromatography coupled with quadrupole

C. G Georgakopoulos; C Tsitsimpikou; M.-H. E Spyridaki

1999-01-01

328

Numerical Study of the semiclassical limit of the Davey-Stewartson II equations  

E-print Network

We present the first detailed numerical study of the semiclassical limit of the Davey-Stewartson II equations both for the focusing and the defocusing variant. We concentrate on rapidly decreasing initial data with a single hump. The formal limit of these equations for vanishing semiclassical parameter $\\epsilon$, the semiclassical equations, are numerically integrated up to the formation of a shock. The use of parallelized algorithms allows to determine the critical time $t_{c}$ and the critical solution for these $2+1$-dimensional shocks. It is shown that the solutions generically break in isolated points similarly to the case of the $1+1$-dimensional cubic nonlinear Schr\\"odinger equation, i.e., cubic singularities in the defocusing case and square root singularities in the focusing case. For small values of $\\epsilon$, the full Davey-Stewartson II equations are integrated for the same initial data up to the critical time $t_{c}$. The scaling in $\\epsilon$ of the difference between these solutions is found to be the same as in the $1+1$ dimensional case, proportional to $\\epsilon^{2/7}$ for the defocusing case and proportional to $\\epsilon^{2/5}$ in the focusing case. We document the Davey-Stewartson II solutions for small $\\epsilon$ for times much larger than the critical time $t_{c}$. It is shown that zones of rapid modulated oscillations are formed near the shocks of the solutions to the semiclassical equations. For smaller $\\epsilon$, the oscillatory zones become smaller and more sharply delimited to lens shaped regions. Rapid oscillations are also found in the focusing case for initial data where the singularities of the solution to the semiclassical equations do not coincide.

C. Klein; K. Roidot

2014-01-19

329

Study of the beam-beam limit in e{sup +}e{sup -} circular colliders  

SciTech Connect

Beam-beam effects limit the luminosity of circular colliders. Once the bunch population exceeds a threshold, the luminosity increases at a slower rate. This phenomenon is called the beam-beam limit. Onset of the beam-beam limit has been analyzed with various simulation methods based on the weak-strong and strong-strong models. We have observed that an incoherent phenomenon is mainly concerned in the beam-beam limit. The simulation have shown that equilibrium distributions of the two colliding beams are distorted from Gaussians when the luminosity is limited. The beam-beam limit is estimated to be (xi) {approx} 0.1 for a B factory with damping time of several thousand turns.

Ohmi, K.; Tawada, M.; Cai, Y.; Kamada, S.; Oide, K.; Qiang, J.

2004-04-02

330

Reminiscences of a journeyman scientist: studies of thermoregulation in non-human primates and humans.  

PubMed

After graduating from Mount Holyoke College in 1948 where I majored in experimental psychology I worked at the College for 2 years with the Johns Hopkins Thermophysiological Unit. My graduate work later at the University of Wisconsin, centering on sensory psychology, culminated in my 1955 PhD thesis on human dark adaptation. I continued work in sensory psychology later with Neal Miller at Yale and then moved to the John B. Pierce Foundation--a Yale affiliate--where I began the studies of thermoregulation that constitute the center of my scientific career. Those studies were largely--later wholly--conducted using microwave energy as a thermal load and were thus published in Bioelectromagnetics even as I played an active role in the Bioelectromagnetics Society. In the beginning this work was centered on the responses of Squirrel Monkeys to thermal loads. Later, serving as Senior Scientist at the Air Force Research Laboratory at San Antonio, I completed an extensive analysis of thermal regulation in humans. I consider this work of special note inasmuch as the extraordinary human thermoregulatory ability was surely among the attributes that were paramount in initially separating humans from the other anthropoid primates. PMID:18780295

Adair, Eleanor Reed

2008-12-01

331

Study on current limiting characteristics of SFCL with two trigger current levels  

NASA Astrophysics Data System (ADS)

In this paper, the superconducting fault current limiter (SFCL) with two trigger current levels was suggested and its effectiveness through the analysis on the current limiting characteristics was described. The proposed SFCL, which consists of the triggering and the limiting components, can limit the fault current by generating the limiting impedance through two steps according to the amplitude of the initial fault current. In case that the fault happens, the lower initial fault current causes the only superconducting element of the triggering component to be quenched. On the other hand, the higher initial fault current makes both the superconducting elements comprising the triggering and the limiting components of the SFCL to be quenched, which contributes to the higher impedance of the SFCL. Therefore, the effective fault current limiting operation of the SFCL can be performed by generating the SFCL’s impedance in proportion to the amplitude of the initial fault current. To confirm the current limiting operation of the proposed SFCL, the short-circuit tests of the SFCL according to the fault angle were carried out and its effective fault current limiting operations could be discussed.

Lim, S. H.

2010-11-01

332

Optimization of a mega-ampere spherical tokamak for beta-limit and confinement studies  

SciTech Connect

Recent favorable results on the START experiment have caused renewed interest in the potential of low aspect ratio tokamaks. To aid in designing a next-step spherical tokamak to study confinement scaling, high beta, and high normalized beta plasmas for minimal cost, the authors have developed a transport scaling and device optimization code. This code STOP, benchmarked against START, includes 10 empirical confinement scaling laws and essential tokamak physics such as stability limits. Parameters are optimized separately for each scaling law and physical goal. Using STOP the authors find for R/a = 1.2 to 2.0 one can achieve {beta}{sub N} = 5, ({beta}) = 31--44%, and easily study predicted confinement degradation with auxiliary heating with just two neutral beams (P{sub NB} < 3.5 MW) for I{sub p} {ge} 0.75 MA, and R{sub 0} {ge} 0.6 m. In contrast, if one insists on using the nominal device parameters, i.e. I{sub p} = 1 MA and R{sub 0} = 0.8 m, with each scaling law, achieving {beta}{sub N} = 5 requires typically P{sub NB} {approx} 7.5 MW. They also conclude that while running D{sup 0} {yields} D{sup +} increases {tau}{sub E} {approx} 25%, with {tau}{sub E} already uncertain by 2--3{times}, one incurs restricted machine access and compromised physics operation.

McCool, S.C.; Wootton, A.J.; Bravenec, R.V. [and others

1994-10-01

333

Engineered human vaccines  

SciTech Connect

The limitations of human vaccines in use at present and the design requirements for a new generation of human vaccines are discussed. The progress in engineering of human vaccines for bacteria, viruses, parasites, and cancer is reviewed, and the data from human studies with the engineered vaccines are discussed, especially for cancer and AIDS vaccines. The final section of the review deals with the possible future developments in the field of engineered human vaccines and the requirement for effective new human adjuvants.

Sandhu, J.S. (Mount Sinai Hospital, Toronto, Ontario (Canada). Div. of Immunology and Neurobiology)

1994-01-01

334

Reconciling Human Smoking Behavior and Machine Smoking Patterns: Implications for Understanding Smoking Behavior and the Impact on Laboratory Studies  

PubMed Central

Introduction Recent Food and Drug Administration legislation enables the mandating of product performance standards for cigarette smoke and the evaluation of manufacturers’ health claims for modified tobacco products. Laboratory studies used for these evaluations, and also to understand tobacco smoke toxicology, use machines to generate smoke. The goal of this review is to critically evaluate methods to assess human smoking behavior and replicate this in the laboratory. Methods Smoking behavior and smoking machine studies were identified using PubMed and publically available databases for internal tobacco company documents. Results The smoking machine was developed to generate smoke to allow for comparing cigarette tar and nicotine yields. The intent was to infer relative human disease risk, but this concept was flawed because humans tailor their smoking to the product and chemical yields and toxicological effects change with different smoking profiles. While smoking machines also allow for mechanistic assessments of smoking-related diseases, the interpretations also are limited. However, available methods to assess how humans puff could be used to provide better laboratory assessments, but these need to be validated. Separately, the contribution of smoke mouth-holding and inhalation to dose need to be assessed, because these parts of smoking are not captured by the smoking machine. Better comparisons of cigarettes might be done by tailoring human puff profiles to the product based on human studies and comparing results across regimens. Conclusions There are major research gaps that limit the use of smoking machine studies for informing tobacco control regulation and mechanistic studies. PMID:19959678

Marian, Catalin; O'Connor, Richard J.; Djordjevic, Mirjana; Rees, Vaughan W.; Hatsukami, Dorothy K.; Shields, Peter G.

2009-01-01

335

Life and Microgravity Sciences Spacelab Mission: Human Research Pilot Study  

NASA Technical Reports Server (NTRS)

The Life Sciences, Microgravity Science and Spacelab Mission contains a number of human experiments directed toward identifying the functional, metabolic and neurological characteristics of muscle weakness and atrophy during space flight. To ensure the successful completion of the flight experiments, a ground-based pilot study, designed to mimic the flight protocols as closely as possible, was carried out in the head-down tilt bed rest model. This report records the rationales, procedures, preliminary results and estimated value of the pilot study, the first of its kind, for 12 of the 13 planned experiments in human research. The bed rest study was conducted in the Human Research Facility at Ames Research Center from July 11 - August 28, 1995. Eight healthy male volunteers performed the experiments before, during and after 17 days bed rest. The immediate purposes of this simulation were to integrate the experiments, provide data in a large enough sample for publication of results, enable investigators to review individual experiments in the framework of a multi-disciplinary study and relay the experience of the pilot study to the mission specialists prior to launch.

Arnaud, Sara B. (Editor); Walker, Karen R. (Editor); Hargens, Alan (Editor)

1996-01-01

336

Framework for Human-Automation Collaboration: Conclusions from Four Studies  

SciTech Connect

The Human Automation Collaboration (HAC) research project is investigating how advanced technologies that are planned for Advanced Small Modular Reactors (AdvSMR) will affect the performance and the reliability of the plant from a human factors and human performance perspective. The HAC research effort investigates the consequences of allocating functions between the operators and automated systems. More specifically, the research team is addressing how to best design the collaboration between the operators and the automated systems in a manner that has the greatest positive impact on overall plant performance and reliability. Oxstrand et al. (2013 - March) describes the efforts conducted by the researchers to identify the research needs for HAC. The research team reviewed the literature on HAC, developed a model of HAC, and identified gaps in the existing knowledge of human-automation collaboration. As described in Oxstrand et al. (2013 – June), the team then prioritized the research topics identified based on the specific needs in the context of AdvSMR. The prioritization was based on two sources of input: 1) The preliminary functions and tasks, and 2) The model of HAC. As a result, three analytical studies were planned and conduced; 1) Models of Teamwork, 2) Standardized HAC Performance Measurement Battery, and 3) Initiators and Triggering Conditions for Adaptive Automation. Additionally, one field study was also conducted at Idaho Falls Power.

Johanna Oxstrand; Katya L. Le Blanc; John O'Hara; Jeffrey C. Joe; April M. Whaley; Heather Medema

2013-11-01

337

Integrative Review of the Literature on Adults with Limited Education and Skills and the Implications for Human Resource Development  

ERIC Educational Resources Information Center

Adults with limited education and skills--those who lack the education and skills needed for full participation in U.S. culture and economy--are increasing in numbers. However, the knowledge base addressing this population and their educational needs is fragmented across the literature of several disciplines. A comprehensive review and critique of…

Hamilton, David W.; Torraco, Richard J.

2013-01-01

338

UH Human Studies Program Policies and Procedures Page 1 University of Hawai`i  

E-print Network

UH Human Studies Program Policies and Procedures Page 1 University of Hawai`i Human Studies Program General Policies and Procedures UH Human Studies Program 1960 East-West Road Biomedical Building B-104 Honolulu, HI 96822 Revised April 3, 2012 #12;UH Human Studies Program Policies and Procedures Page 2 UH

Olsen, Stephen L.

339

Raman microspectroscopic approach to the study of human granulocytes.  

PubMed Central

A sensitive confocal Raman microspectrometer was employed to record spectra of nuclei and cytoplasmic regions of single living human granulocytes. Conditions were used that ensured cell viability and reproducibility of the spectra. Identical spectra were obtained from the nuclei of neutrophilic, eosinophilic, and basophilic granulocytes, which yield information about DNA and protein secondary structure and DNA-protein ratio. The cytoplasmic Raman spectra of the three cell types are very different. This was found to be mainly due to the abundant presence of peroxidases in the cytoplasmic granules of neutrophilic granulocytes (myeloperoxidase) and eosinophilic granulocytes (eosinophil peroxidase). Strong signal contributions of the active site heme group(s) of these enzymes were found. This paper illustrates the potentials and limitations for Raman spectroscopic analysis of cellular constituents and processes. PMID:1760504

Puppels, G J; Garritsen, H S; Segers-Nolten, G M; de Mul, F F; Greve, J

1991-01-01

340

A Comparative Study of Definitions on Limit and Continuity of Functions  

ERIC Educational Resources Information Center

Differences in definitions of limit and continuity of functions as treated in courses on calculus and in rigorous undergraduate analysis yield contradictory outcomes and unexpected language. There are results about limits in calculus that are false by the definitions of analysis, functions not continuous by one definition and continuous by…

Shipman, Barbara A.

2012-01-01

341

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

342

Exploring the damage limitation possibilities of mineral fibres for future integrated solutions: an in vitro study.  

PubMed

Owing to their possible carcinogenic effect, asbestos and other silica derivatives have been identified as priority substances for risk reduction and prevention of pollution. Neutralisation procedures have thus become a topical research subject in many European and American countries. In the present study, silica derivatives (asbestos-containing and asbestos substitutes like slag wool, rock wool, cement asbestos) were fully impregnated with an epoxy resin according to the procedure used for the in situ impregnation with viscous polymeric media, which penetrate and cement the fibres in place and reduce the risk of their dispersion in air. Untreated and treated samples were used to investigate their in vitro interaction with a human continuous epithelial cell line (NCTC 2544 keratinocytes) and test the resin's efficiency in passivating the surface activity of the fibrous particulate. SEM and morpho-quantitative data evidenced that impregnation with the epoxy resin modifies the mineral fibres' bioactivity (reduction of cell adhesion and decreased spread/round cell ratio) and demonstrated the value of in vitro cell testing after passivation as a risk-assessment procedure. These tests could be used for the rapid determination of the level of passivation of new synthetic mineral fibrous materials subjected to resin impregnation. PMID:12602472

Gabbanelli, F; Mattioli-Belmonte, M; Giantomassi, F; Rimondini, L; Viticchi, C; Biagini, G; Torricelli, P; Gualtieri, A F; Lesci, I G; Giardino, R

2003-01-01

343

Improved detection limit in rapid detection of human enterovirus 71 and coxsackievirus A16 by a novel reverse transcription-isothermal multiple-self-matching-initiated amplification assay.  

PubMed

Rapid detection of human enterovirus 71 (EV71) and coxsackievirus A16 (CVA16) is important in the early phase of hand-foot-and-mouth disease (HFMD). In this study, we developed and evaluated a novel reverse transcription-isothermal multiple-self-matching-initiated amplification (RT-IMSA) assay for the rapid detection of EV71 and CVA16 by use of reverse transcriptase, together with a strand displacement DNA polymerase. Real-time RT-IMSA assays using a turbidimeter and visual RT-IMSA assays to detect EV71 and CVA16 were established and completed in 1 h, and the reported corresponding real-time reverse transcription-loop-mediated isothermal amplification (RT-LAMP) assays targeting the same regions of the VP1 gene were adopted as parallel tests. Through testing VP1 RNAs transcribed in vitro, the real-time RT-IMSA assays exhibited better linearity of quantification, with R(2) values of 0.952 (for EV71) and 0.967 (for CVA16), than the real-time RT-LAMP assays, which had R(2) values of 0.803 (for EV71) and 0.904 (for CVA16). Additionally, the detection limits of the real-time RT-IMSA assays (approximately 937 for EV71 and 67 for CVA16 copies/reaction) were higher than those of real-time RT-LAMP assays (approximately 3,266 for EV71 and 430 for CVA16 copies/reaction), and similar results were observed in the visual RT-IMSA assays. The new approaches also possess high specificities for the corresponding targets, with no cross-reactivity observed. In clinical assessment, compared to commercial reverse transcription-quantitative PCR (qRT-PCR) kits, the diagnostic sensitivities of the real-time RT-IMSA assays (96.4% for EV71 and 94.6% for CVA16) were higher than those of the real-time RT-LAMP assays (91.1% for EV71 and 90.8% for CVA16). The visual RT-IMSA assays also exhibited the same results. In conclusion, this proof-of-concept study suggests that the novel RT-IMSA assay is superior to the RT-LAMP assay in terms of detection limit and has the potential to rapidly detect EV71 and CVA16 viruses. PMID:24648558

Ding, Xiong; Nie, Kai; Shi, Lei; Zhang, Yong; Guan, Li; Zhang, Dan; Qi, Shunxiang; Ma, Xuejun

2014-06-01

344

Simulation study of melanoma detection in human skin tissues by laser-generated surface acoustic waves  

NASA Astrophysics Data System (ADS)

Air pollution has been correlated to an increasing number of cases of human skin diseases in recent years. However, the investigation of human skin tissues has received only limited attention, to the point that there are not yet satisfactory modern detection technologies to accurately, noninvasively, and rapidly diagnose human skin at epidermis and dermis levels. In order to detect and analyze severe skin diseases such as melanoma, a finite element method (FEM) simulation study of the application of the laser-generated surface acoustic wave (LSAW) technique is developed. A three-layer human skin model is built, where LSAW's are generated and propagated, and their effects in the skin medium with melanoma are analyzed. Frequency domain analysis is used as a main tool to investigate such issues as minimum detectable size of melanoma, filtering spectra from noise and from computational irregularities, as well as on how the FEM model meshing size and computational capabilities influence the accuracy of the results. Based on the aforementioned aspects, the analysis of the signals under the scrutiny of the phase velocity dispersion curve is verified to be a reliable, a sensitive, and a promising approach for detecting and characterizing melanoma in human skin.

Chen, Kun; Fu, Xing; Dorantes-Gonzalez, Dante J.; Lu, Zimo; Li, Tingting; Li, Yanning; Wu, Sen; Hu, Xiaotang

2014-07-01

345

Simulation study of melanoma detection in human skin tissues by laser-generated surface acoustic waves.  

PubMed

Air pollution has been correlated to an increasing number of cases of human skin diseases in recent years. However, the investigation of human skin tissues has received only limited attention, to the point that there are not yet satisfactory modern detection technologies to accurately, noninvasively, and rapidly diagnose human skin at epidermis and dermis levels. In order to detect and analyze severe skin diseases such as melanoma, a finite element method (FEM) simulation study of the application of the laser-generated surface acoustic wave (LSAW) technique is developed. A three-layer human skin model is built, where LSAW’s are generated and propagated, and their effects in the skin medium with melanoma are analyzed. Frequency domain analysis is used as a main tool to investigate such issues as minimum detectable size of melanoma, filtering spectra from noise and from computational irregularities, as well as on how the FEM model meshing size and computational capabilities influence the accuracy of the results. Based on the aforementioned aspects, the analysis of the signals under the scrutiny of the phase velocity dispersion curve is verified to be a reliable, a sensitive, and a promising approach for detecting and characterizing melanoma in human skin. PMID:25057963

Chen, Kun; Fu, Xing; Dorantes-Gonzalez, Dante J; Lu, Zimo; Li, Tingting; Li, Yanning; Wu, Sen; Hu, Xiaotang

2014-07-01

346

HUMAN BIOLOGYHUMAN BIOLOGYHUMAN BIOLOGY This major is designed for students seeking a focused course of study in human  

E-print Network

HUMAN BIOLOGYHUMAN BIOLOGYHUMAN BIOLOGY This major is designed for students seeking a focused course of study in human anatomy, physiology, metabolism, and/or evolution. The BS degree includes: Applied Physiology, Biomedical Sciences, Nutrition and Metabolism, and Human Evolutionary Biology. The BA

Rohs, Remo

347

Trait Mindfulness as a Limiting Factor for Residual Depressive Symptoms: An Explorative Study Using Quantile Regression  

PubMed Central

Mindfulness has been suggested to be an important protective factor for emotional health. However, this effect might vary with regard to context. This study applied a novel statistical approach, quantile regression, in order to investigate the relation between trait mindfulness and residual depressive symptoms in individuals with a history of recurrent depression, while taking into account symptom severity and number of episodes as contextual factors. Rather than fitting to a single indicator of central tendency, quantile regression allows exploration of relations across the entire range of the response variable. Analysis of self-report data from 274 participants with a history of three or more previous episodes of depression showed that relatively higher levels of mindfulness were associated with relatively lower levels of residual depressive symptoms. This relationship was most pronounced near the upper end of the response distribution and moderated by the number of previous episodes of depression at the higher quantiles. The findings suggest that with lower levels of mindfulness, residual symptoms are less constrained and more likely to be influenced by other factors. Further, the limiting effect of mindfulness on residual symptoms is most salient in those with higher numbers of episodes. PMID:24988072

Radford, Sholto; Eames, Catrin; Brennan, Kate; Lambert, Gwladys; Crane, Catherine; Williams, J. Mark G.; Duggan, Danielle S.; Barnhofer, Thorsten

2014-01-01

348

Study Towards Human Aided Construction of Large Lunar Telescopes  

NASA Astrophysics Data System (ADS)

On the Moon, unique situations exist for observing the universe. The Polar areas contain permanently shadowed areas, which are among the coldest places in our solar system, within which the infrared background radiation that can disturb measurements is very low. Also disturbances generated on Earth are mostly out of view and thus the measurements can be much more sensitive in all wavelengths. The South Pole offers a good location for building such an observatory. Clementine mission data indicate that permanently shadowed areas are located within a few kilometers of a areas that are almost permanently lit by the sun. By placing a communication relay on one of the lunar mountains it is also possible to have a communications link for periods in which these shadowed areas can not be seen directly from Earth. The South Polar region of the Moon is also interesting geologically because it is located inside the largest basin on the moon (South Pole - Aitken Basin) as well as the possibility that ice may exist there. Shackleton Crater is suggested as a site for the placement and construction of the Lunar South Pole Infrared Telescope together with a communication relay lander at Malapert Mountain and another communication relay and energy supply lander at the Peak of Eternal Light, located near the rim of Shackleton. A near infrared telescope has been designed for emplacement in Shackleton that appears to have the same capabilities as the Next Generation Space Telescope except for sky coverage, which will be limited by the location and orientation. The telescope has a diameter of 8 meters and is an altitude-azimuth design. The bearings will be made of superconducting magnets that use fluxpinning to stabilize themselves while at the same time they are very energy-efficient. The foundation will be dug and constructed in-situ using robots and telepresence together with virtual reality and local laser rangefinders. If all goes well the telescope would have settlement no greater than 0,03 mm during operation. It would be possible for astronauts to maintain, repair and upgrade the telescope much in the same way that the Hubble Space Telescope has been maintained. When the telescope is built, an infrastructure will also have been created for energy supply and communications that can be used in subsequent missions. The total mission can be achieved by launching 3 Ariane 5 rockets in the year 2006 configuration that can launch 20,000 kg into GTO. New studies of the construction of even larger telescopes have also been undertaken.. One additional aspect that will be very important is the synergy between humans and robots and their role in transport, construction, operation, maintenance, etc. is addressed in these new studies. Also an attempt will be made to make a parametric cost model for different scenario's as well as the technology readiness levels for the techniques necessary to build a telescope with the capacity of the 'planet finder', equivalent up to 1000 sq m of photon collecting surface. Part of the scenario definition and conceptual design of a large lunar telescope has also been done in the lunar base design workshop, held from 10-21 of June at ESTEC, NL. After the conceptual phase there will be a more engineering oriented workshop, which will be held in the concurrent design facility at ESTEC. This paper includes discussion of recent progress on these studies.

vanSusante, P. J.

2002-01-01

349

Experimental study of the mechanical properties of human abdominal fascia.  

PubMed

The aim of the study is to characterise mechanical properties of human abdominal fascia according to its direction of loading and localization. The one-dimensional tensile behaviour of human abdominal fascia and its orthotropy has been studied experimentally using human umbilical (UF) and transversalis fascia (FT). The specimens have been cut and stretched parallel and orthogonal to the main fibre bundles. 90 specimens 10 mm wide and up to 70 mm long have been tested. The following mechanical parameters, characterising tensile properties of human abdominal fascia, have been calculated from the obtained stress-stretch ratio curves: maximal stress T(L)(max), stretch ratio at maximal stress ?(T(max)), maximal stretch ratio at failure ?(max), and a secant modulus E(i). The tissue strips obtained from defined areas reveal break stress between 0.63 and 1.99 MPa for FT and 0.93-1.61 MPa for UF. The parameter estimation has shown that in the physiological strain range specimens from both type of fascia can be considered orthotropic material according to their secant module, maximum stress T(L)(max) and stretch at maximum stress. Anisotropy factor AF (ratio of the stress in longitudinal and transverse directions) has been used to establish the level of the orthotropy of material and its variations with the stretch ratio. The maximum AF is 4.3 for FT at 20% deformation and 3.3 for UF at 5% deformation. The differences between the mechanical properties of FT and UF according to localization are not statistically significant thus the mechanical properties of human abdominal fascia are not affected by the localization. PMID:21095153

Kirilova, Miglena; Stoytchev, Stoyan; Pashkouleva, Dessislava; Kavardzhikov, Vasil

2011-01-01

350

Human semen study around and away from gold mine area.  

PubMed

Gold was first detected in human semen in 1981. The entry of gold into semen was hypothesized through food items. Earlier reports identified gold in semen as important for good quality of semen. The infertility rate could be low around gold mine area when compared to other places. The aim of the study was to verify this. Towards this, the quality of human semen around a gold mine (Kolar, India) was evaluated and compared to that from a place which was 2000 km away from a gold mine (Jamnagar, India). A total number of 254 semen samples from Kolar and 437 from Jamnagar were evaluated. The fertility rate was higher in Kolar region. The semen samples studied for both places showed that the semen quality was superior in Kolar gold field area. PMID:22237809

Prasad, S B; Skandhan, K P; Sing, G

2011-01-01

351

Noninvasive studies of human visual cortex using neuromagnetic techniques  

SciTech Connect

The major goals of noninvasive studies of the human visual cortex are: to increase knowledge of the functional organization of cortical visual pathways; and to develop noninvasive clinical tests for the assessment of cortical function. Noninvasive techniques suitable for studies of the structure and function of human visual cortex include magnetic resonance imaging (MRI), positron emission tomography (PET), single photon emission tomography (SPECT), scalp recorded event-related potentials (ERPs), and event-related magnetic fields (ERFs). The primary challenge faced by noninvasive functional measures is to optimize the spatial and temporal resolution of the measurement and analytic techniques in order to effectively characterize the spatial and temporal variations in patterns of neuronal activity. In this paper we review the use of neuromagnetic techniques for this purpose. 8 refs., 3 figs.

Aine, C.J.; George, J.S.; Supek, S. (Los Alamos National Lab., NM (USA)); Maclin, E.L. (Veterans Administration Medical Center, Albuquerque, NM (USA). Center for Magnetoencephalography)

1990-01-01

352

Sequencing studies in human genetics: design and interpretation  

PubMed Central

Next-gene ration sequencing is becoming the primary discovery tool in human genetics. There have been many clear successes in identifying genes that are responsible for Mendelian diseases, and sequencing approaches are now poised to identify the mutations that cause undiagnosed childhood genetic diseases and those that predispose individuals to more common complex diseases. There are, however, growing concerns that the complexity and magnitude of complete sequence data could lead to an explosion of weakly justified claims of association between genetic variants and disease. Here, we provide an overview of the basic workflow in next-generation sequencing studies and emphasize, where possible, measures and considerations that facilitate accurate inferences from human sequencing studies. PMID:23752795

Goldstein, David B.; Allen, Andrew; Keebler, Jonathan; Margulies, Elliott H.; Petrou, Steven; Petrovski, Slave; Sunyaev, Shamil

2014-01-01

353

Improving a method for the study of limit cycles of the Lienard equation Hector Giacomini* and Sebastien Neukirch  

E-print Network

Improving a method for the study of limit cycles of the Lie´nard equation Hector Giacomini* and Se introduced a method for the study of limit cycles of the Lie´nard system, x y F(x), y x, where F(x) is an odd of the Lie´nard system: dx dt y F x , dy dt x, 1 where F(x) is an odd polynomial of arbitrary degree

Neukirch, Sébastien

354

Human colonic biota studied by ribosomal DNA sequence analysis  

Microsoft Academic Search

Human colonic biota is a complex microbial ecosystem that serves as a host defense. Unlike most microbial ecosystems, its composition has been studied extensively by relatively efficient culture methods. We have compared an established culture-based method with direct amplification and partial sequencing of cloned 16S rRNAgenesfromahumanfecalspecimen.NinecyclesofPCRwerealsocomparedwith35cycles.Coloniesand clonedampliconswereclassifiedbycomparingtheirribosomalDNA(rDNA;DNAcodingforrRNA)sequences with rDNA sequences of known phylogeny. Quantitative culture recovered 58% of the microscopic

KENNETH H. WILSON; R. B. Blitchington

1996-01-01

355

Human pharmacological studies of a new transdermal system containing nitroglycerin  

Microsoft Academic Search

Summary  A new transdermal therapeutic system (TTS) for the administration of nitroglycerin (NTG) was tested in human pharmacological\\u000a studies in 26 healthy volunteers. Plasma concentrations and haemodynamic responses were determined after the application of\\u000a the system in different dosages. The concentrations of NTG reached in the plasma were uniform and dose-related, i.e. dependent\\u000a on the drug-release area, and showed only minor

P. Mtiller; P. R. Imhof; F. Burkart; L.-C. Chu; A. Gérardin

1982-01-01

356

The sociobiological perspectives in the study of human evolution  

Microsoft Academic Search

The idea of a new multilevel approach to an understanding of regularities of evolution and its consequences for the study\\u000a of human evolution is analysed. Three levels of evolutionary process are defined: (1) genetic level-the basic one. Memory\\u000a of this level is coded, fixed, collected and translated by means of chemical structures (mainly of nucleic acids). The super-organismic\\u000a system is

V. Leonovicova

1992-01-01

357

Advancing the management and control of typhoid fever: a review of the historical role of human challenge studies.  

PubMed

Typhoid infection causes considerable morbidity and mortality worldwide, particularly in settings where lack of clean water and inadequate sanitation facilitate disease spread through faecal-oral transmission. Improved understanding of the pathogenesis, immune control and microbiology of Salmonella Typhi infection can help accelerate the development of improved vaccines and diagnostic tests necessary for disease control. S. Typhi is a human-restricted pathogen; therefore animal models are limited in their relevance to human infection. During the latter half of the 20th century, induced human infection ("challenge") studies with S. Typhi were used effectively to assess quantitatively the human host response to challenge and to measure directly the efficacy of typhoid vaccines in preventing clinical illness. Here, the findings of these historic challenge studies are reviewed, highlighting the pivotal role that challenge studies have had in improving our understanding of the host-pathogen interaction, and illustrating issues relevant to modern typhoid challenge model design. PMID:24491597

Waddington, Claire S; Darton, Thomas C; Woodward, William E; Angus, Brian; Levine, Myron M; Pollard, Andrew J

2014-05-01

358

Illness perceptions and activity limitations in osteoarthritis of the knee: a case report intervention study.  

PubMed

This case report describes the process and outcome of an intervention where illness perceptions (IPs) were targeted in order to reduce limitations in daily activities. The patient was a 45-year-old woman diagnosed with posttraumatic secondary osteoarthritis of the lateral patella-femoral cartilage of the right knee. At baseline, the patient reported maladaptive IPs on the Brief Illness Perception Questionnaire Dutch Language Version and limitations in walking stairs, cycling and walking. Fewer limitations in daily activities are hypothesized by changing maladaptive IPs into more favourable IPs. In this case report, discussing maladaptive IPs with the patient was the main intervention. A participatory decision making model was used as a design by which the maladaptive IP were discussed. Six out of eight maladaptive IPs changed favourably and there was a clinically relevant decrease in limitations of daily activities. The Global Perceived Effect was rated as much improved. PMID:24011782

de Raaij, Edwin J; Pool, Jan; Maissan, François; Wittink, Harriët

2014-04-01

359

A statistical study of the geological limits to Advanced Piston Coring: ODP Legs 101-149  

E-print Network

The Advanced Piston Corer (APC), a soft sediment coring system developed from the hydraulic piston corer (HPC), allows recovery of ocean sediments with minimal coring disturbance. As a coring too[, the APC system is subject to limitations imposed...

Lee, Yir-Der Eddy

2012-06-07

360

40 CFR 26.1603 - Operation of the Human Studies Review Board.  

Code of Federal Regulations, 2010 CFR

... 2010-07-01 false Operation of the Human Studies Review Board. 26.1603 Section...PROTECTION AGENCY GENERAL PROTECTION OF HUMAN SUBJECTS Review of Proposed and Completed Human Research § 26.1603 Operation of...

2010-07-01

361

40 CFR 26.1603 - Operation of the Human Studies Review Board.  

Code of Federal Regulations, 2011 CFR

... 2011-07-01 false Operation of the Human Studies Review Board. 26.1603 Section...PROTECTION AGENCY GENERAL PROTECTION OF HUMAN SUBJECTS Review of Proposed and Completed Human Research § 26.1603 Operation of...

2011-07-01

362

40 CFR 26.1603 - Operation of the Human Studies Review Board.  

Code of Federal Regulations, 2012 CFR

... 2012-07-01 false Operation of the Human Studies Review Board. 26.1603 Section...PROTECTION AGENCY GENERAL PROTECTION OF HUMAN SUBJECTS Review of Proposed and Completed Human Research § 26.1603 Operation of...

2012-07-01

363

40 CFR 26.1605 - Operation of the Human Studies Review Board.  

Code of Federal Regulations, 2013 CFR

... 2013-07-01 false Operation of the Human Studies Review Board. 26.1605 Section...PROTECTION AGENCY GENERAL PROTECTION OF HUMAN SUBJECTS Review of Proposed and Completed Human Research § 26.1605 Operation of...

2013-07-01

364

Optical storage of high-density information beyond the diffraction limit: A quantum study  

SciTech Connect

We propose an optical readout scheme allowing a proof of principle of information extraction below the diffraction limit. This technique, which could lead to improvement in data readout density onto optical disks, is independent from the wavelength and numerical aperture of the reading apparatus, and involves a multipixel array detector. Furthermore, we show how to use nonclassical light in order to perform a bit discrimination beyond the quantum noise limit.

Delaubert, V.; Treps, N.; Fabre, C. [Laboratoire Kastler Brossel, UPMC, Case 74, 4 Place Jussieu, 75252 Paris Cedex 05 (France); Bo, G. [Laboratoire Pierre Aigrain, Ecole Normale Superieure, 24 rue Lhomond, 75231 Paris Cedex 05 (France)

2006-01-15

365

A comparative study of limited-angle cone-beam reconstruction methods for breast tomosynthesis  

Microsoft Academic Search

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

Yiheng Zhang; Heang-Ping Chan; Berkman Sahiner; Jun Wei; Mitchell M. Goodsitt; Lubomir M. Hadjiiski; Jun Ge; Chuan Zhou

2006-01-01

366

Rapid-throughput glycomics applied to human milk oligosaccharide profiling for large human studies.  

PubMed

Glycomic analysis is the comprehensive determination of glycan (oligosaccharide) structures with quantitative information in a biological sample. Rapid-throughput glycomics is complicated due to the lack of a template, which has greatly facilitated analysis in the field of proteomics. Furthermore, the large similarities in structures make fragmentation spectra (as obtained in electron impact ionization and tandem mass spectrometry) less definitive for identification as it has been in metabolomics. In this study, we develop a concept of rapid-throughput glycomics on human milk oligosaccharides, which have proven to be an important bioactive component of breast milk, providing the infant with protection against pathogenic infection and supporting the establishment of a healthy microbiota. To better understand the relationship between diverse oligosaccharides structures and their biological function as anti-pathogenic and prebiotic compounds, large human studies are needed, which necessitate rapid- to high-throughput analytical platforms. Herein, a complete glycomics methodology is presented, evaluating the most effective human milk oligosaccharide (HMO) extraction protocols, the linearity and reproducibility of the nano-liquid chromatography chip time-of-flight mass spectrometry (nano-LC chip-TOF MS) method, and the efficacy of newly developed, in-house software for chromatographic peak alignment that allows for rapid data analysis. High instrument stability and retention time reproducibility, together with the successful automated alignment of hundreds of features in hundreds of milk samples, allow for the use of an HMO library for rapid assignment of fully annotated structures. PMID:25358913

Totten, Sarah M; Wu, Lauren D; Parker, Evan A; Davis, Jasmine C C; Hua, Serenus; Stroble, Carol; Ruhaak, L Renee; Smilowitz, Jennifer T; German, J Bruce; Lebrilla, Carlito B

2014-12-01

367

The safety of studies with intravenous ? 9 -tetrahydrocannabinol in humans, with case histories  

Microsoft Academic Search

Rationale  Delta-9-tetrahydrocannabinol (THC) is one of the few cannabinoid receptor ligands that can be used to probe the cannabinoid\\u000a system in humans. Despite increasing interest in the cannabinoid receptor system, use of intravenous THC as a research tool\\u000a has been limited by concerns about its abuse liability and psychoactive effects.\\u000a \\u000a \\u000a \\u000a \\u000a Objectives  This study aims to evaluate the safety of all intravenous THC

Michelle Carbuto; R. Andrew Sewell; Ashley Williams; Kim Forselius-Bielen; Gabriel Braley; Jacqueline Elander; Brian Pittman; Ashley Schnakenberg; Savita Bhakta; Edward Perry; Mohini Ranganathan; Deepak Cyril D’Souza

368

A critical review of epidemiologic studies of radiofrequency exposure and human cancers.  

PubMed Central

This paper reviews studies that have assessed associations between likely exposure to radiofrequency (RF) transmissions and various types of human cancer. These studies include three cluster investigations and five studies relating to general populations; all of these studies consider place of residence at the time of cancer diagnosis in regard to proximity to radio or television transmitters. There are also five relevant occupational cohort studies and several case-control studies of particular types of cancer. These studies assessed a large number of possible associations. Several positive associations suggesting an increased risk of some types of cancer in those who may have had greater exposure to RF emissions have been reported. However, the results are inconsistent: there is no type of cancer that has been consistently associated with RF exposures. The epidemiologic evidence falls short of the strength and consistency of evidence that is required to come to a reasonable conclusion that RF emissions are a likely cause of one or more types of human cancer. The evidence is weak in regard to its inconsistency, the design of the studies, the lack of detail on actual exposures, and the limitations of the studies in their ability to deal with other likely relevant factors. In some studies there may be biases in the data used PMID:10229715

Elwood, J M

1999-01-01

369

Study on Recovery Performance of High Tc Superconducting Tapes for Resistive Type Superconducting Fault Current Limiter Applications  

NASA Astrophysics Data System (ADS)

Recent advances in reliable production of long length high temperature superconducting (HTS) tapes have resulted in commercial application of superconducting fault current limiters (SFCLs) in electrical utility networks. SFCL gives excellent technical performance when compared to conventional fault current limiters. The fast self-recovery from normal state to superconducting state immediately after the fault removal is an essential criterion for resistive type SFCL operation. In this paper, results on AC over-current testing of 1st generation (1G) Bi2223 tapes and 2nd generation (2G) YBCO coated conductors operating at 77 K are reported. From these results, the recovery time is estimated for different available HTS tapes in the market. The current limiting tests have also been performed to study the effective current limitation. Further, the recovery characteristics after the current limitation are quantitatively discussed for repetitive faults for different time intervals in the range of 100 ms to few seconds.

kar, Soumen; Kulkarni, Sandeep; Dixit, Manglesh; Singh, Kuwar Pal; Gupta, Alok; Balasubramanyam, P. V.; Sarangi, S. K.; Rao, V. V.

370

Topology of sarcoplasmic reticulum Ca2+-ATPase: an infrared study of thermal denaturation and limited proteolysis.  

PubMed Central

Sarcoplasmic reticulum Ca2+-ATPase structure and organization in the membrane has been studied by infrared spectroscopy by decomposition of the amide I band. Besides the component bands assignable to secondary structure elements such as alpha-helix, beta-sheet, etc...., two unusual bands, one at 1,645 cm(-1) in H2O buffer and the other at 1,625 cm(-1) in D2O buffer are present. By perturbing the protein using temperature and limited proteolysis, the band at 1,645 cm(-1) is tentatively assigned to alpha-helical segments located in the cytoplasmic domain and coupled to beta-sheet structure, whereas the band at 1,625 cm(-1) arises probably from monomer-monomer contacts in the native oligomeric protein. The secondary structure obtained is 33% alpha-helical segments in the transmembrane plus stalk domain; 20% alpha-helix and 22% beta-sheet in the cytoplasmic domain plus 19% turns and 6% unordered structure. Thermal unfolding of Ca2+-ATPase is a complex process that cannot be described as a two-state denaturation. The results obtained are compatible with the idea that the protein is an oligomer at room temperature. The loss of the 1,625 cm(-1) band upon heating would be consistent with a disruption of the oligomers in a process that later gives rise to aggregates (appearance of the 1,618 cm(-1) band). This picture would also be compatible with early results suggesting that processes governing Ca2+ accumulation and ATPase activity are uncoupled at temperatures above 37 degrees C, so that while ATPase activity proceeds at high rates, Ca2+ accumulation is inhibited. PMID:9605321

Echabe, I.; Dornberger, U.; Prado, A.; Goni, F. M.; Arrondo, J. L.

1998-01-01

371

van der Waals clusters in the ultraquantum limit: A Monte Carlo study M. Meierovich, A. Mushinski, and M. P. Nightingalea)  

E-print Network

there was no need to go beyond variational Monte Carlo, we rely in this article on diffusion Monte Carlo to improvevan der Waals clusters in the ultraquantum limit: A Monte Carlo study M. Meierovich, A. Mushinski are studied by diffusion quantum Monte-Carlo techniques. In particular we study the unbinding transition

Nightingale, Peter

372

Limited Applicability of GW9662 to Elucidate PPAR?-Mediated Fatty Acid Effects in Primary Human T-Helper Cells  

PubMed Central

Synthetic antagonists of the nuclear receptor PPAR? such as GW9662 are widely used to elucidate receptor-mediated ligand effects. In addition and complementary to recent work, we examined whether GW9662 is suitable to serve for mechanistic investigation in T-helper cells. Human peripheral blood mononuclear cells (PBMC) were preincubated with increasing concentrations of GW9662 (0, 0.4, 2, and 10??mol/L) 30?min before adding the c9,t11-isomer of conjugated linoleic acid (c9,t11-CLA) as representative of PPAR?-activating fatty acids with immunomodulatory properties. Corresponding cultures were incubated with GW9662 in the absence of the fatty acid. After 19?h, cells were mitogen stimulated for further 5?h. Subsequently, intracellular IL-2 was measured in CD3+CD4+ lymphocytes by means of flow cytometry. 100??mol/L c9,t11-CLA reduced the number of T-helper cells expressing IL-2 by 68%. GW9662 failed to abrogate this fatty acid effect, likely due to the fact that the compound exerted an own inhibitory effect on IL-2 production. Moreover, GW9662 dose-dependently induced cell death in human leukocytes. These results suggest that application of GW9662 is not conducive in this experimental setting. PMID:25054074

Jaudszus, Anke; Gruen, Michael; Roth, Alexander; Jahreis, Gerhard

2014-01-01

373

FT-Raman spectroscopy study of human breast tissue  

NASA Astrophysics Data System (ADS)

Optical spectroscopy has been extensively studied as a potential in vivo diagnostic tool to provide information about the chemical and morphologic structure of tissue. Raman Spectroscpy is an inelastic scattering process that can provide a wealth of spectral features that can be related to the specific molecular structure of the sample. This article reports results of an in vitro study of the FT-Raman human breast tissue spectra. An Nd:YAG laser at 1064nm was used as the excitation source in the FT-Raman Spectrometer. The neoplastic human breast samples, both Fibroadenoma and ICD, were obtained during therapeutical routine medical procedures required by the primary disease, and the non-diseased human tissue was obtained in plastic surgery. No sample preparation was needed for the FT-Raman spectra collection. The FT-Raman spectra were recorded from normal, benign (Fibroadenomas) and malignant (IDC-Intraductal Carcinoma) samples, adding up 51 different areas. The main spectral differences of a typical FT-Raman spectra of a Normal (Non-diseased), Fibroadenoma, and Infiltrating Ductal Carcinoma (IDC) breast tissue at the interval of 600 to 1800cm-1, which may differentiate diagnostically the sample, were found in the bands of 1230 to 1295cm-1, 1440 to 1460 cm-1 and 1650 to 1680 cm-1, assigned to the vibrational bands of the carbohydrate-amide III, proteins and lipids, and carbohydrate-amide I, respectively.

Bitar Carter, Renata A.; Martin, Airton A.; Netto, Mario M.; Soares, Fernando A.

2004-07-01

374

From human skin to Nano-Skin: an experimental study on human skin temperature measurement  

Microsoft Academic Search

The human state in human–machine systems should be monitored to improve system performance. In monitoring it is preferable to use physiological cues such as skin temperature. The sensing capabilities of human skin were analyzed. The sensing system of human skin was modeled, and inspired the design of a Nano-Skin for physiological measurement in dynamic human–machine contact for human state recognition.

Hongjie Leng; Yingzi Lin

2011-01-01

375

Functional MRI studies of human vision on a clinical imager  

SciTech Connect

During the past decade, Magnetic Resonance Imaging (MRI) has become the method of choice for imaging the anatomy of the human brain. Recently, Belliveau and colleagues have reported the use of echo planar magnetic resonance imaging (EPI) to image patterns of neural activity. Here, we report functional MR imaging in response to visual stimulation without the use of contrast agents, and without the extensive hardware modifications required for EPI. Regions of activity were observed near the expected locations of V1, V2 and possibly V3 and another active region was observed near the parietal-occipital sulcus on the superior surface of the cerebrum. These locations are consistent with sources observed in neuromagnetic studies of the human visual response.

George, J.S.; Lewine, J.D.; Aine, C.J.; van Hulsteyn, D.; Wood, C.C. [Los Alamos National Lab., NM (United States); Sanders, J.; Maclin, E. [Veterans Administration Medical Center, Albuquerque, NM (United States); Belliveau, J.W. [Massachusetts General Hospital, Charlestown, MA (United States); Caprihan, A. [Lovelace Medical Foundation, Albuquerque, NM (United States)

1992-09-01

376

Resveratrol: A review of preclinical studies for human cancer prevention  

SciTech Connect

The search for novel and effective cancer chemopreventive agents has led to the identification of various naturally occurring compounds one of which is resveratrol (trans-3,4',5-trihydroxystilbene), a phytoalexin derived from the skin of grapes and other fruits. Resveratrol is known to have potent anti-inflammatory and antioxidant effects and to inhibit platelet aggregation and the growth of a variety of cancer cells. Its potential chemopreventive and chemotherapeutic activities have been demonstrated in all three stages of carcinogenesis (initiation, promotion, and progression), in both chemically and UVB-induced skin carcinogenesis in mice, as well as in various murine models of human cancers. Evidence from numerous in vitro and in vivo studies has confirmed its ability to modulate various targets and signaling pathways. This review discusses the current preclinical and mechanistic data available and assesses resveratrol's anticancer effects to support its potential as an anticancer agent in human populations.

Athar, Mohammad; Back, Jung Ho; Tang Xiuwei [Department of Dermatology, College of Physicians and Surgeons, Columbia University, 630 West 168th Street VC15-204, New York, NY 10032 (United States); Kim, Kwang Ho [Department of Dermatology, Hallym University College of Medicine (Korea, Republic of); Kopelovich, Levy [Division of Cancer Prevention, National Cancer Institute, Bethesda, MD 20892 (United States); Bickers, David R. [Department of Dermatology, College of Physicians and Surgeons, Columbia University, 630 West 168th Street VC15-204, New York, NY 10032 (United States); Kim, Arianna L. [Department of Dermatology, College of Physicians and Surgeons, Columbia University, 630 West 168th Street VC15-204, New York, NY 10032 (United States)], E-mail: ak309@columbia.edu

2007-11-01

377

Crowdsourcing and Human Computation: Systems, Studies and Platforms  

E-print Network

Crowdsourcing and human computation are transforming human-computer interaction, and CHI has led the way. The seminal publication in human computation was initially published in CHI in 2004 [1], and the first paper ...

Bernstein, Michael

2011-01-01

378

Resveratrol and Clinical Trials: The Crossroad from In Vitro Studies to Human Evidence  

PubMed Central

Resveratrol (3,5,4’-trihydroxy-trans-stilbene) is a non-flavonoid polyphenol that may be present in a limited number of food-stuffs such as grapes and red wine. Resveratrol has been reported to exert a plethora of health benefits through many different mechanisms of action. This versatility and presence in the human diet have drawn the worldwide attention of many research groups over the past twenty years, which has resulted in a huge output of in vitro and animal (preclinical) studies. In line with this expectation, many resveratrol-based nutraceuticals are consumed all over the world with questionable clinical/scientific support. In fact, the confirmation of these benefits in humans through randomized clinical trials is still very limited. The vast majority of preclinical studies have been performed using assay conditions with a questionable extrapolation to humans, i.e. too high concentrations with potential safety concerns (adverse effects and drug interactions), short-term exposures, in vitro tests carried out with non-physiological metabolites and/or concentrations, etc. Unfortunately, all these hypothesis-generating studies have contributed to increased the number of ‘potential’ benefits and mechanisms of resveratrol but confirmation in humans is very limited. Therefore, there are many issues that should be addressed to avoid an apparent endless loop in resveratrol research. The so-called ‘Resveratrol Paradox’, i.e., low bioavailability but high bioactivity, is a conundrum not yet solved in which the final responsible actor (if any) for the exerted effects has not yet been unequivocally identified. It is becoming evident that resveratrol exerts cardioprotective benefits through the improvement of inflammatory markers, atherogenic profile, glucose metabolism and endothelial function. However, safety concerns remain unsolved regarding chronic consumption of high RES doses, specially in medicated people. This review will focus on the currently available evidence regarding resveratrol’s effects on humans obtained from randomized clinical trials. In addition, we will provide a critical outlook for further research on this molecule that is evolving from a minor dietary compound to a possible multi-target therapeutic drug. PMID:23448440

Tome-Carneiro, Joao; Larrosa, Mar; Gonzalez-Sarrias, Antonio; Tomas-Barberan, Francisco A.; Garcia-Conesa, Maria Teresa; Espin, Juan Carlos

2013-01-01

379

Study and Analysis of Heat Transfer Limitation of Separated Heat Pipe  

NASA Astrophysics Data System (ADS)

satellite and spacecraft. evaporator, heat isolation and condenser along the axial direction. The working fluid absorbs heat and evaporates in evaporator, and then the vapor flows to condenser and gives out heat. The condensed liquid is pumped to evaporator by wick. By the circulation, the heat can by transferred continuously. heat pipe as follow: - Vapor-liquid two phase flow inside pipe; - The manner of latent heat to transfer heat; - Automatic circulation by working fluid flowing - A certain extent of vacuum. and the traditional heat pipe, that is, the vapor fluid and liquid fluid flow along the same direction. So it is obviously that the separated heat pipe has special internal heat transfer characteristic and crisis. This paper has regard for the heat transfer crisis of the separated heat pipe, and meanwhile relevant calculation and analysis have been done. 1. FLOW TYPE OF THE WORKING FLUID IN SEPARATED HEAT PIPE 2. HEAT TRANSFER CRISIS IN THE EVAPORATOR 3. CARRYING PHENOMENON INSIDE SEPARATED HEAT PIPE 4. THE STAGNANT FLOW PHENOMENON AND THE BACKWARD FLOW PHENOMENON IN EVAPORATOR CONCLUSION transfer limitation of location burn-out, and the heat transfer limitation of flow unconventionality in erective pipe. The carrying phenomenon can occurs not only in evaporator but also in condenser of separated heat pipe. It is in the evaporator that should take place the heat transfer limitation of liquid film dry-out at first. Then with the increasing of heat flux, the heat transfer limitation of location burn-out would happen. In order to avoid the heat transfer limitation of flow unconventionality in erective pipe, the length and diameter of the outflow tube and inflow tube must be reasonably calculated to control the flow velocity of the working fluid inside pipe. Key words:Separated Heat PipeHeat Transfer LimitationDry-OutCarryingStagnancy

Mou, Qizheng; Mou, Kai

2002-01-01

380

A simulation study of the lower limit of permeability for a commercially feasible gas well  

E-print Network

permeability layer acts as if it were a horizontal fracture into the formation. 26 Using an economic cut-off limit of 50 MCF/day on the shallower well and 80 MCF/day on the deeper well, the data in Figures 5 and 7 and Table 4, indicate that economic wells... permeability layer acts as if it were a horizontal fracture into the formation. 26 Using an economic cut-off limit of 50 MCF/day on the shallower well and 80 MCF/day on the deeper well, the data in Figures 5 and 7 and Table 4, indicate that economic wells...

Nwaogwugwu, Chimela Wachukwu

2012-06-07

381

Additional road markings as an indication of speed limits: results of a field experiment and a driving simulator study.  

PubMed

Although speed limits are indicated by road signs, road users are not always aware, while driving, of the actual speed limit on a given road segment. The Roads and Traffic Agency developed additional road markings in order to support driver decisions on speed on 70 km/h roads in Flanders-Belgium. In this paper the results are presented of two evaluation studies, both a field study and a simulator study, on the effects of the additional road markings on speed behaviour. The results of the field study showed no substantial effect of the markings on speed behaviour. Neither did the simulator study, with slightly different stimuli. Nevertheless an effect on lateral position was noticed in the simulator study, showing at least some effect of the markings. The role of conspicuity of design elements and expectations towards traffic environments is discussed. Both studies illustrate well some strengths and weaknesses of observational field studies compared to experimental simulator studies. PMID:20380925

Daniels, Stijn; Vanrie, Jan; Dreesen, An; Brijs, Tom

2010-05-01

382

Human SLC26A1 Gene Variants: A Pilot Study  

PubMed Central

Kidney stones are a global health problem, incurring massive health costs annually. Why stones recur in many patients remains unknown but likely involves environmental, physiological, and genetic factors. The solute linked carrier (SLC) 26A1 gene has previously been linked to kidney stones in mice. SLC26A1 encodes the sulfate anion transporter 1 (SAT1) protein, and its loss in mice leads to hyperoxaluria and calcium oxalate renal stones. To investigate the possible involvement of SAT1 in human urolithiasis, we screened the SLC26A1 gene in a cohort of 13 individuals with recurrent calcium oxalate urolithiasis, which is the commonest type. DNA sequence analyses showed missense mutations in seven patients: one individual was heterozygous R372H; 4 individuals were heterozygous Q556R; one patient was homozygous Q556R; and one patient with severe nephrocalcinosis (requiring nephrectomy) was homozygous Q556R and heterozygous M132T. The M132 amino acid in human SAT1 is conserved with 15 other species and is located within the third transmembrane domain of the predicted SAT1 protein structure, suggesting that this amino acid may be important for SAT1 function. These initial findings demonstrate genetic variants in SLC26A1 of recurrent stone formers and warrant wider independent studies of SLC26A1 in humans with recurrent calcium oxalate stones. PMID:24250268

Dawson, Paul A.; Sim, Pearl; Mudge, David W.

2013-01-01

383

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

384

Limited lithium isotopic fractionation during progressive metamorphic dehydration in metapelites: A case study  

E-print Network

Limited lithium isotopic fractionation during progressive metamorphic dehydration in metapelites-zone metamorphism far removed from the pluton to partially melted rocks adjacent to the pluton. Lithium on the aureole scale. Published by Elsevier B.V. Keywords: Lithium; Isotope fractionation; Metamorphic

Mcdonough, William F.

385

Rural Income-Generating Programs and Fertility Limitation: Evidence from a Microdemographic Study in Nepal.  

ERIC Educational Resources Information Center

Examines effects of participation in cooperative farm development programs on fertility behavior in Nepal. Data were collected by ethnographic and survey methods. Results confirm co-op membership increases contraceptive use. Concludes co-op membership creates social pressure to limit fertility. Suggests policy implications. (TES)

Axinn, William G.

1992-01-01

386

Redundant Manipulator Self-Motion Topology Under Joint Limits with an 8-DOF Case Study  

NASA Technical Reports Server (NTRS)

This paper investigates the topology of self-motion manifolds for serial redundant manipulators with revolute joints in the presence of joint limits. It is known that the preimages of singular taskpoints divide the configuration space into regions where self-motion manifolds are homotopic.

Luck, C. L.; Lee, S.

1993-01-01

387

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

388

Experimental and analytical studies for forming limit of AZ31 alloy on warm sheet metal forming  

Microsoft Academic Search

Since magnesium alloy sheet usually exhibits poor press formability, the sheet forming for complex shaped part has many difficult problems. Among these problems, the die design to prevent some defects is one of the important process variables. Therefore, the data for forming limit of AZ31 sheet is necessary to prevent the defect and get the good formed part. In this

Y. S. Lee; M. C. Kim; S. W. Kim; Y. N. Kwon; S. W. Choi; J. H. Lee

2007-01-01

389

A case study: Residue reduction at Deer Park Refining Limited Partnership  

Microsoft Academic Search

With input from Shell Synthetic Fuels Inc. (SSFI), Deer Park Refining Limited Partnership (DPRLP) analyzed options for managing the bottom of the barrel to extinction, with an objective of high return on investment. DPRLP is a joint venture of PEMEX and Shell Oil Company. This Gulf Coast refiner processes 227M BBL\\/D of heavy, high sulfur crude. This paper discusses the

Geehan

1996-01-01

390

Understanding the Limits of Marxist Approaches to Sociocultural Studies of Science Education  

ERIC Educational Resources Information Center

In the first three sections of this paper we comment on some of the ideas developed in the forum papers, pointing out possible misunderstandings and constructing new explanations that clarify arguments we made in the original article. In the last section we expand the discussion raised in the original paper, elaborating on the limits of the use of…

Lima, Paulo, Jr.; Ostermann, Fernanda; Rezende, Flavia

2014-01-01

391

Human habitation field study of the Habitat Demonstration Unit (HDU)  

NASA Astrophysics Data System (ADS)

Landing and supporting a permanent outpost on a planetary surface represents humankind's capability to expand its own horizons and challenge current technology. With this in mind, habitability of these structures becomes more essential given the longer durations of the missions. The purpose of this evaluation was to obtain preliminary human-in-the-loop performance data on the Habitat Demonstration Unit (HDU) in a Pressurized Excursion Module (PEM) configuration during a 14-day simulated lunar exploration field trial and to apply this knowledge to further enhance the habitat's capabilities for forward designs. Human factors engineers at the NASA/Johnson Space Center's Habitability and Human Factors Branch recorded approximately 96 h of crew task performance with four work stations. Human factors measures used during this study included the NASA Task Load Index (TLX) and customized post questionnaires. Overall the volume for the PEM was considered acceptable by the crew; however; the habitat's individual work station volume was constrained when setting up the vehicle for operation, medical operations, and suit maintenance while general maintenance, logistical resupply, and geo science was considered acceptable. Crew workload for each station indicated resupply as being the lowest rated, with medical operations, general maintenance, and geo science tasks as being light, while suit maintenance was considered moderate and general vehicle setup being rated the highest. Stowage was an issue around the habitat with the Space Exploration Vehicle (SEV) resupply stowage located in the center of the habitat as interfering with some work station volumes and activities. Ergonomics of the geo science station was considered a major issue, especially with the overhead touch screens.

Litaker, Harry L.; Archer, Ronald D.; Szabo, Richard; Twyford, Evan S.; Conlee, Carl S.; Howard, Robert L.

2013-10-01

392

Histopathology of ruby and argon laser lesions in monkey and human retina. A comparative study.  

PubMed Central

Suprathreshold fundus lesions produced by ruby and argon laser photocoagulation were studied within 24 hours by light and electron microscopy. It was shown that damage was maximal in the outer retina in all ruby laser lesions and extramacular argon laser lesions. In both monkey and human, inner retinal damage occurred independently of outer retinal damage in macular lesions produced by the argon laser. In lesions produced by equal energy, inner retinal damage was more severe in humans than in monkeys. In both species outer retinal damage was less severe in the foveal than the parafoveal region and this disparity was greater in humans than in monkeys. These findings are important to the therapeutic use of argon laser energy for mascular disease. In particular, absortion of energy in the inner retina reduces the energy available in the treatment of subretinal lesions in the foveal area, and causes unwanted neuroretinal damage. The higher sensitivity to argon laser irradiation of the human fovea compared with the monkey fovea, has not been appreciated when defining laser safety limits. Images PMID:812546

Marshall, J.; Hamilton, A. M.; Bird, A. C.

1975-01-01

393

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

394

The genomics of preterm birth: from animal models to human studies  

PubMed Central

Preterm birth (delivery at less than 37 weeks of gestation) is the leading cause of infant mortality worldwide. So far, the application of animal models to understand human birth timing has not substantially revealed mechanisms that could be used to prevent prematurity. However, with amassing data implicating an important role for genetics in the timing of the onset of human labor, the use of modern genomic approaches, such as genome-wide association studies, rare variant analyses using whole-exome or genome sequencing, and family-based designs, holds enormous potential. Although some progress has been made in the search for causative genes and variants associated with preterm birth, the major genetic determinants remain to be identified. Here, we review insights from and limitations of animal models for understanding the physiology of parturition, recent human genetic and genomic studies to identify genes involved in preterm birth, and emerging areas that are likely to be informative in future investigations. Further advances in understanding fundamental mechanisms, and the development of preventative measures, will depend upon the acquisition of greater numbers of carefully phenotyped pregnancies, large-scale informatics approaches combining genomic information with information on environmental exposures, and new conceptual models for studying the interaction between the maternal and fetal genomes to personalize therapies for mothers and infants. Information emerging from these advances will help us to identify new biomarkers for earlier detection of preterm labor, develop more effective therapeutic agents, and/or promote prophylactic measures even before conception. PMID:23673148

2013-01-01

395

Transgenic mice expressing human glucocerebrosidase variants: utility for the study of Gaucher disease.  

PubMed

Gaucher disease is an autosomal recessively inherited storage disorder caused by deficiency of the lysosomal hydrolase, acid ?-glucosidase. The disease manifestations seen in Gaucher patients are highly heterogeneous as is the responsiveness to therapy. The elucidation of the precise factors responsible for this heterogeneity has been challenging as the development of clinically relevant animal models of Gaucher disease has been problematic. Although numerous murine models for Gaucher disease have been described each has limitations in their specific utility. We describe here, transgenic murine models of Gaucher disease that will be particularly useful for the study of pharmacological chaperones. We have produced stable transgenic mouse strains that individually express wild type, N370S and L444P containing human acid ?-glucosidase and show that each of these transgenic lines rescues the lethal phenotype characteristic of acid ?-glucosidase null mice. Both the N370S and L444P transgenic models show early and progressive elevations of tissue sphingolipids with L444P mice developing progressive splenic Gaucher cell infiltration. We demonstrate the potential utility of these new transgenic models for the study of Gaucher disease pathogenesis. In addition, since these mice produce only human enzyme, they are particularly relevant for the study of pharmacological chaperones that are specifically targeted to human acid ?-glucosidase and the common mutations underlying Gaucher disease. PMID:23642305

Sanders, Angela; Hemmelgarn, Harmony; Melrose, Heather L; Hein, Leanne; Fuller, Maria; Clarke, Lorne A

2013-08-01

396

An in vitro study of the effect of mifepristone and ulipristal acetate on human sperm functions.  

PubMed

Ulipristal acetate (UPA) and mifepristone are currently well-established agents for emergency contraception. Both drugs are selective progestogen receptor modulators which have been shown to have better efficacy than the widely used levonorgestrel in prevention of pregnancy. However, there is only limited information on the action of UPA on sperm function. The present study compared the in vitro biological effects of mifepristone and UPA on human sperm functions. Spermatozoa from semen samples with normal semen parameters were isolated. Capacitated spermatozoa were pre-incubated with 0.04, 0.4, 4 and 40 ?m mifepristone or UPA for 1 h. Sperm motility, viability, DNA integrity, capacitation, spontaneous acrosome reaction, spontaneous hyperactivation, zona pellucida (ZP) binding capability and intracellular calcium concentration ([Ca(2+) ]i ) were determined. The effects of mifepristone and UPA on progesterone-induced acrosome reaction, hyperactivation and [Ca(2+) ]i were also studied. Our results showed that mifepristone and UPA dose-dependently suppressed progesterone-induced acrosome reaction, hyperactivation and [Ca(2+) ]i at concentrations ?0.4 ?m in human spermatozoa. Both compounds did not affect sperm motility, viability, DNA integrity, capacitation, spontaneous acrosome reaction, spontaneous hyperactivation, ZP binding capability and [Ca(2+) ]i . This study demonstrated that UPA and mifepristone modulate human sperm functions by acting as progesterone antagonists. The results enable us to gain a better understanding of the mechanisms by which mifepristone and UPA work for emergency contraception, and provide a scientific basis for their clinical application. PMID:25168311

Ko, J K Y; Huang, V W; Li, R H W; Yeung, W S B; Ho, P C; Chiu, P C N

2014-11-01

397

A numerical study of the small dispersion limit of the Korteweg-de Vries equation and asymptotic solutions  

NASA Astrophysics Data System (ADS)

We study numerically the small dispersion limit for the Korteweg-de Vries (KdV) equation ut+6uux+?2uxxx=0 for ??1 and give a quantitative comparison of the numerical solution with various asymptotic formulae for small ? in the whole (x,t)-plane. The matching of the asymptotic solutions is studied numerically.

Grava, T.; Klein, C.

2012-12-01

398

Haemodynamic studies with peruvoside in human congestive heart failure.  

PubMed

The immediate haemodynamic effects of peruvoside, a cardiac glycoside obtained from the Indian plant Thevetia neriifolia Juss, were studied in six patients with congestive heart failure. The drug was found to have an immediate and powerful positive inotropic and negative chronotropic effect, like ouabain, on the failing human heart. Oral peruvoside was also effective in the treatment of congestive heart failure when used on a short-term as well as a long-term basis. It therefore seems that peruvoside is a useful cardiac glycoside in the management of congestive heart failure in man as a quick-acting intravenous preparation. It is equally effective when used orally. PMID:4919553

Bhatia, M L; Manchanda, S C; Roy, S B

1970-09-26

399

Haemodynamic Studies with Peruvoside in Human Congestive Heart Failure  

PubMed Central

The immediate haemodynamic effects of peruvoside, a cardiac glycoside obtained from the Indian plant Thevetia neriifolia Juss, were studied in six patients with congestive heart failure. The drug was found to have an immediate and powerful positive inotropic and negative chronotropic effect, like ouabain, on the failing human heart. Oral peruvoside was also effective in the treatment of congestive heart failure when used on a short-term as well as a long-term basis. It therefore seems that peruvoside is a useful cardiac glycoside in the management of congestive heart failure in man as a quick-acting intravenous preparation. It is equally effective when used orally. PMID:4919553

Bhatia, M. L.; Manchanda, S. C.; Roy, Sujoy B.

1970-01-01

400

Detection limits and cost comparisons of human- and gull-associated conventional and quantitative PCR assays in artificial and environmental waters.  

PubMed

Some molecular methods for tracking fecal pollution in environmental waters have both PCR and quantitative PCR (qPCR) assays available for use. To assist managers in deciding whether to implement newer qPCR techniques in routine monitoring programs, we compared detection limits (LODs) and costs of PCR and qPCR assays with identical targets that are relevant to beach water quality assessment. For human-associated assays targeting Bacteroidales HF183 genetic marker, qPCR LODs were 70 times lower and there was no effect of target matrix (artificial freshwater, environmental creek water, and environmental marine water) on PCR or qPCR LODs. The PCR startup and annual costs were the lowest, while the per reaction cost was 62% lower than the Taqman based qPCR and 180% higher than the SYBR based qPCR. For gull-associated assays, there was no significant difference between PCR and qPCR LODs, target matrix did not effect PCR or qPCR LODs, and PCR startup, annual, and per reaction costs were lower. Upgrading to qPCR involves greater startup and annual costs, but this increase may be justified in the case of the human-associated assays with lower detection limits and reduced cost per sample. PMID:24583609

Riedel, Timothy E; Zimmer-Faust, Amity G; Thulsiraj, Vanessa; Madi, Tania; Hanley, Kaitlyn T; Ebentier, Darcy L; Byappanahalli, Muruleedhara; Layton, Blythe; Raith, Meredith; Boehm, Alexandria B; Griffith, John F; Holden, Patricia A; Shanks, Orin C; Weisberg, Stephen B; Jay, Jennifer A

2014-04-01

401

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

402

Detection limits and cost comparisons of human- and gull-associated conventional and quantitative PCR assays in artificial and environmental waters  

USGS Publications Warehouse

Some molecular methods for tracking fecal pollution in environmental waters have both PCR and quantitative PCR (qPCR) assays available for use. To assist managers in deciding whether to implement newer qPCR techniques in routine monitoring programs, we compared detection limits (LODs) and costs of PCR and qPCR assays with identical targets that are relevant to beach water quality assessment. For human-associated assays targeting Bacteroidales HF183 genetic marker, qPCR LODs were 70 times lower and there was no effect of target matrix (artificial freshwater, environmental creek water, and environmental marine water) on PCR or qPCR LODs. The PCR startup and annual costs were the lowest, while the per reaction cost was 62% lower than the Taqman based qPCR and 180% higher than the SYBR based qPCR. For gull-associated assays, there was no significant difference between PCR and qPCR LODs, target matrix did not effect PCR or qPCR LODs, and PCR startup, annual, and per reaction costs were lower. Upgrading to qPCR involves greater startup and annual costs, but this increase may be justified in the case of the human-associated assays with lower detection limits and reduced cost per sample.

Riedel, Timothy E.; Zimmer-Faust, Amity G.; Thulsiraj, Vanessa; Madi, Tania; Hanley, Kaitlyn T.; Ebentier, Darcy L.; Byappanahalli, Muruleedhara N.; Layton, Blythe; Raith, Meredith; Boehm, Alexandria B.; Griffith, John F.; Holden, Patricia A.; Shanks, Orin C.; Weisberg, Stephen B.; Jay, Jennifer A.

2014-01-01

403

Extravehicular activities limitations study. Volume 2: Establishment of physiological and performance criteria for EVA gloves  

NASA Technical Reports Server (NTRS)

One of the major probelms faced in Extravehicular Activity (EVA) glove development has been the absence of concise and reliable methods to measure the effects of EVA gloves on human hand capabilities. This report describes the development of a standardized set of tests designed to assess EVA-gloved hand capabilities in six measurement domains: Range of Motion, Strength, Tactile Perception, Dexterity, Fatigue, and Comfort. Based on an assessment of general human hand functioning and EVA task requirements several tests within each measurement domain were developed to provide a comprehensive evaluation. All tests were designed to be conducted in a glove box with the bare hand as a baseline and the EVA glove at operating pressure. A test program was conducted to evaluate the tests using a representative EVA glove. Eleven test subjects participated in a repeated-measures design. The report presents the results of the tests in each capability domain.

Ohara, John M.; Briganti, Michael; Cleland, John; Winfield, Dan

1988-01-01

404

The dopaminergic basis of human behaviors: a review of molecular imaging studies  

PubMed Central

This systematic review describes human molecular imaging studies which have investigated alterations in extracellular DA levels during performance of behavioral tasks. Whilst heterogeneity in experimental methods limits meta-analysis, we describe the advantages and limitations of different methodological approaches. Interpretation of experimental results may be limited by regional cerebral blood flow (rCBF) changes, head movement and choice of control conditions. We revisit our original study of striatal DA release during video-game playing (Koepp et al., 1998) to illustrate the potentially confounding influences of head movement and alterations in rCBF. Changes in [11C]raclopride binding may be detected in extrastriatal as well as striatal brain regions – however we review evidence which suggests that extrastriatal changes may not be clearly interpreted in terms of DA release. Whilst several investigations have detected increases in striatal extracellular DA concentrations during task components such as motor learning and execution, reward-related processes, stress and cognitive performance, the presence of potentially biasing factors should be carefully considered (and, where possible, accounted for) when designing and interpreting future studies. PMID:19481108

Egerton, Alice; Mehta, Mitul A; Montgomery, Andrew J; Lappin, Julia M; Howes, Oliver D; Reeves, Suzanne J; Cunningham, Vincent J; Grasby, Paul M

2013-01-01

405

A comparative study on the optical limiting properties of different nano spinel ferrites with Z-scan technique  

SciTech Connect

Highlights: ? First report in which the optical limiting properties of five different nano spinel ferrites are compared. ? The obtained nonlinearity fits to a two-photon like absorption process. ? Except for NiFe{sub 2}O{sub 4}, the observed nonlinearity has contributions from excited state absorption. ? A size dependent optical limiting response is obtained. ? Among the investigated ferrites, ZnFe{sub 2}O{sub 4} is found to be a better candidate for the optical limiting applications. -- Abstract: We report the optical limiting properties of five different spinel ferrites, NiFe{sub 2}O{sub 4}, Ni{sub 0.5}Zn{sub 0.5}Fe{sub 2}O{sub 4}, ZnFe{sub 2}O{sub 4}, Ni{sub 0.5}Co{sub 0.5}Fe{sub 2}O{sub 4}, and CoFe{sub 2}O{sub 4} with an average particle grain size of 8 nm. The optical limiting properties are investigated using the open aperture Z-scan technique. The obtained nonlinearity fits to a two-photon like absorption process. Except for NiFe{sub 2}O{sub 4}, the observed nonlinearity has contributions from excited state absorption. The optical limiting response is also studied against particle size and the nonlinearity is found to increase with increasing particle size within the range of our investigations. On comparing the optical limiting properties, ZnFe{sub 2}O{sub 4} is found to be a better candidate for the optical limiting applications. To the best of our knowledge, this is the first report where the optical limiting properties of spinel ferrites are compared.

Thomas, Jeevan Job; Krishnan, Shiji [School of Pure and Applied Physics, Mahatma Gandhi University, Kottayam, Kerala 686560 (India)] [School of Pure and Applied Physics, Mahatma Gandhi University, Kottayam, Kerala 686560 (India); Sridharan, K.; Philip, Reji [Light and Matter Physics Group, Raman Research Institute, C.V. Raman Avenue, Sadashivanagar, Bangalore 560080 (India)] [Light and Matter Physics Group, Raman Research Institute, C.V. Raman Avenue, Sadashivanagar, Bangalore 560080 (India); Kalarikkal, Nandakumar, E-mail: nkkalarikkal@mgu.ac.in [School of Pure and Applied Physics, Mahatma Gandhi University, Kottayam, Kerala 686560 (India) [School of Pure and Applied Physics, Mahatma Gandhi University, Kottayam, Kerala 686560 (India); Centre for Nanoscience and Nanotechnology, Mahatma Gandhi University, Kottayam, Kerala 686560 (India)

2012-08-15

406

A theoretical study of limit cycle oscillations of plenum air cushions  

NASA Astrophysics Data System (ADS)

Air cushion vehicles (ACV) are prone to the occurrence of dynamic instabilities which frequently appear as stable finite amplitude oscillations. The aim of this work is to ascertain if the non-linearities characteristics of ACV dynamics generate limit cycle oscillations for cushion systems operating at conditions for which a linear theory predicts instability. The types of non-linearity that can occur are discussed, and an analysis is presented for a single cell flexible skirted plenum chamber constrained to move in pure heave only. Two cushion feed cases are considered: a plenum box supply and a duct. The results obtained by a Galerkin/describing function analysis are compared with those generated by a full numerical simulation. For the plenum box supply system, it is shown that the limit cycles can be suppressed by using a piston to introduce high frequency small amplitude volume oscillations into the plenum chamber.

Hinchey, M. J.; Sullivan, P. A.

1981-11-01

407

Breaking the diffraction limit by saturation in stimulated-Raman-scattering microscopy: A theoretical study  

NASA Astrophysics Data System (ADS)

We present a theoretical investigation on the saturation of stimulated Raman scattering (SRS) and propose an application of it to break the diffraction limit in SRS microscopy. In our proposed scheme, a donut-shaped Stokes beam is used to saturate SRS at the rim of a focused Gaussian pump beam; thus the addition of another Gaussian Stokes beam can only induce additional stimulated Raman loss to the pump beam in a small area inside the donut-shaped beam. Resembling stimulated-emission-depletion microscopy, this method can significantly improve the lateral imaging resolution. Compared with the diffraction-limited resolution, theoretical simulations show that it may be possible to double the spatial resolution with a few TW/cm2 of laser intensity. Such super-resolution could greatly enhance the advantage of SRS microscopy for potential applications.

Gong, Li; Wang, Haifeng

2014-07-01

408

A Long-term Follow-up Study on the Engraftment of Human Hematopoietic Stem Cells in Sheep  

PubMed Central

Xenograft models of human hematopoiesis are essential to the study of the engraftment and proliferative potential of human hematopoietic stem cells (HSCs) in vivo. Immunodeficient mice and fetal sheep are often used as xenogeneic recipients because they are immunologically naive. In this study, we transplanted human HSCs into fetal sheep and assessed the long-term engraftment of transplanted human HSCs after birth. Fourteen sheep were used in this study. In 4 fetal sheep, HSCs were transduced with homeo-box B4 (HOXB4) gene before transplantation, which promoted the expansion of HSCs. Another 4 fetal sheep were subjected to non-myeloablative conditioning with busulfan. Seven of these 8 sheep showed successful engraftment of human HSCs (1–3% of colony-forming units) as assessed after the birth of fetal sheep (5 months post-transplantation), although HOXB4-transduced HSCs showed sustained engraftment for up to 40 months. Intact HSCs were transplanted into six non-conditioned fetal sheep, and human colony-forming units were not detected in the sheep after birth. These results suggest that, as compared with mouse models, where the short lifespan of mice limits long-term follow-up of HSC engraftment, the fetal sheep model provides a unique perspective for evaluating long-term engraftment and proliferation of human HSCs. PMID:25048264

Abe, Tomoyuki; Hanazono, Yutaka; Nagao, Yoshikazu

2014-01-01

409

Prospective study on stereotactic radiotherapy of limited-stage non–small-cell lung cancer  

Microsoft Academic Search

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

Morten. Hoyer; Henrik D. Roed; Anders Traberg Hansen; Lars Ohlhuis; Jorgen Petersen; Hanne Nellemann; Anne Kiil Berthelsen; Cai D. Grau; Svend Aage D. Engelholm; Hans D. von der Maase

2006-01-01

410

Yeast Modulation of Human Dendritic Cell Cytokine Secretion: An In Vitro Study  

PubMed Central

Probiotics are live microorganisms which when administered in adequate amounts confer a health benefit on the host. The concept of individual microorganisms influencing the makeup of T cell subsets via interactions with intestinal dendritic cells (DCs) appears to constitute the foundation for immunoregulatory effects of probiotics, and several studies have reported probiotic strains resulting in reduction of intestinal inflammation through modulation of DC function. Consequent to a focus on Saccharomyces boulardii as the fundamental probiotic yeast, very little is known about hundreds of non-Saccharomyces yeasts in terms of their interaction with the human gastrointestinal immune system. The aim of the present study was to evaluate 170 yeast strains representing 75 diverse species for modulation of inflammatory cytokine secretion by human DCs in vitro, as compared to cytokine responses induced by a S. boulardii reference strain with probiotic properties documented in clinical trials. Furthermore, we investigated whether cytokine inducing interactions between yeasts and human DCs are dependent upon yeast viability or rather a product of membrane interactions regardless of yeast metabolic function. We demonstrate high diversity in yeast induced cytokine profiles and employ multivariate data analysis to reveal distinct clustering of yeasts inducing similar cytokine profiles in DCs, highlighting clear species distinction within specific yeast genera. The observed differences in induced DC cytokine profiles add to the currently very limited knowledge of the cross-talk between yeasts and human immune cells and provide a foundation for selecting yeast strains for further characterization and development toward potentially novel yeast probiotics. Additionally, we present data to support a hypothesis that the interaction between yeasts and human DCs does not solely depend on yeast viability, a concept which may suggest a need for further classifications beyond the current definition of a probiotic. PMID:24816850

Smith, Ida M.; Christensen, Jeffrey E.; Arneborg, Nils; Jespersen, Lene

2014-01-01

411

The normal human appendix: a light and electron microscopic study.  

PubMed Central

Human appendices from 3 to 12 years old children were studied by light and electron microscopy. Three morphological zones were determined: sub-epithelial (or lymphoid lamina propria), parafollicular, and follicular. The fine structure of these regions has been studied and discussed with regard to the thymus-dependent and thymus-independent regions of other lymphoid organs. Two types of lymphocytes, 'light' and 'dark', and intermediate forms, were also found. The light ones are the more abundant in the epithelium and within the parafollicular post-capillary venules; they form groups or clusters between epithelial cells, becoming like blast cells and possibly maturing into plasma cells in the sub-epithelial region. Whether light lymphocytes are T or B or both is discussed. The general conclusion is that the human appendix, at least in children, has the characteristics of a well-developed lymphoid organ, suggesting that it has important immunological functions. Images Fig. 1 Fig. 2 Fig. 3 Fig. 4 Fig. 5 Fig. 6 Fig. 7 Fig. 8 Fig. 9 Fig. 10 Fig. 11 Fig. 12 Fig. 13 Fig. 14 Fig. 15 Fig. 16 Fig. 17 Fig. 18 Fig. 19 Fig. 20 Fig. 21 Fig. 22 PMID:649505

Gorgollon, P

1978-01-01

412

Human transcriptome array for high-throughput clinical studies.  

PubMed

A 6.9 million-feature oligonucleotide array of the human transcriptome [Glue Grant human transcriptome (GG-H array)] has been developed for high-throughput and cost-effective analyses in clinical studies. This array allows comprehensive examination of gene expression and genome-wide identification of alternative splicing as well as detection of coding SNPs and noncoding transcripts. The performance of the array was examined and compared with mRNA sequencing (RNA-Seq) results over multiple independent replicates of liver and muscle samples. Compared with RNA-Seq of 46 million uniquely mappable reads per replicate, the GG-H array is highly reproducible in estimating gene and exon abundance. Although both platforms detect similar expression changes at the gene level, the GG-H array is more sensitive at the exon level. Deeper sequencing is required to adequately cover low-abundance transcripts. The array has been implemented in a multicenter clinical program and has generated high-quality, reproducible data. Considering the clinical trial requirements of cost, sample availability, and throughput, the GG-H array has a wide range of applications. An emerging approach for large-scale clinical genomic studies is to first use RNA-Seq to the sufficient depth for the discovery of transcriptome elements relevant to the disease process followed by high-throughput and reliable screening of these elements on thousands of patient samples using custom-designed arrays. PMID:21317363

Xu, Weihong; Seok, Junhee; Mindrinos, Michael N; Schweitzer, Anthony C; Jiang, Hui; Wilhelmy, Julie; Clark, Tyson A; Kapur, Karen; Xing, Yi; Faham, Malek; Storey, John D; Moldawer, Lyle L; Maier, Ronald V; Tompkins, Ronald G; Wong, Wing Hung; Davis, Ronald W; Xiao, Wenzhong

2011-03-01

413

Humanimalia: A journal of human/animal interface studies  

NSDL National Science Digital Library

The website for the new journal Humanimalia, published by DePauw University, recently released its first issue. The appeal and importance of the journal goes beyond appearance, as the journal states that the study of the human/animal interface has been a "neglected" area of research. In the "Humanimalifesto" link, a lengthy explanation is given, and it notes that one of the main goals of the journal is "to approach animal/human interfaces without relying on stigmatizing critique of philosophical, political, or cultural antagonists." The first issue consists of articles and reviews, including an article called "Hooters for Neuters: Sexist Transgressive Animal Advocacy Campaign?" and a review of the popular Michael Pollan book, "The Omnivore's Dilemma: A Natural History of Four Meals". Visitors interested in submitting an article to the peer-reviewed, interdisciplinary journal should check out the guidelines in the "Call-for-Papers" link on the left side of the page. The "Notes and Bulletins" link, also on the left side of the page, has a notice of an Animal Studies meeting at NYU, and the "Links" area includes information on upcoming conferences.

414

A limited number of pseudouridine residues in the human atac spliceosomal UsnRNAs as compared to human major spliceosomal UsnRNAs.  

PubMed Central

Two forms of spliceosomes were found in higher eukaryotes. The major form contains the U1, U2, U4, U5, and U6 snRNAs; the minor form contains the U11, U12, U4atac, U5, and U6atac snRNAs. Assembly and function of the major form are based on a complex dynamic of UsnRNA-UsnRNA and UsnRNA-pre-mRNA interactions, and the involved UsnRNA segments are highly posttranscriptionally modified in plants and vertebrates. To further characterize the minor form of spliceosomes, we looked for the psi residues in HeLa cells' U11, U12, U4atac, and U6atac snRNAs, using chemical approaches. Four psi residues were detected in total for these four atac UsnRNAs, compared to 20 in their counterparts of the major spliceosomes. The two psi residues detected in U12 are also found in U2 snRNA. One of them belongs to the branch-site-recognition sequence. It forms one of the base pairs that bulge out the A residue, responsible for the nucleophilic attack. Conservation of this strategic psi residue probably reflects a functional role. Another psi residue was detected in a U4atac snRNA segment involved in formation of helix II with U6atac. The fourth one was detected in the additional stem-loop structure present at the 3' end of U6atac snRNA. Differences in psi content of the atac and major UsnRNAs of human cells may participate in the differentiation of the two splicing systems. Based on secondary structure similarity, U2 and U12 snRNAs on the one hand and U4 and U4atac snRNAs on the other hand may share common psi synthases. PMID:10580478

Massenet, S; Branlant, C

1999-01-01

415

Age and decisions to limit life support for patients with acute lung injury: a prospective cohort study  

PubMed Central

Introduction The proportion of elderly Americans admitted to the intensive care unit (ICU) in the last month of life is rising. Hence, challenging decisions regarding the appropriate use of life support are increasingly common. The objective of this study was to estimate the association between patient age and the rate of new limitations in the use of life support, independent of daily organ dysfunction status, following acute lung injury (ALI) onset. Methods This was a prospective cohort study of 490 consecutive patients without any limitations in life support at the onset of ALI. Patients were recruited from 11 ICUs at three teaching hospitals in Baltimore, Maryland, USA, and monitored for the incidence of six pre-defined limitations in life support, with adjustment for baseline comorbidity and functional status, duration of hospitalization before ALI onset, ICU severity of illness, and daily ICU organ dysfunction score. Results The median patient age was 52 (range: 18 to 96), with 192 (39%) having a new limitation in life support in the ICU. Of patients with a new limitation, 113 (59%) had life support withdrawn and died, 53 (28%) died without resuscitation, and 26 (14%) survived to ICU discharge. Each ten-year increase in patient age was independently associated with a 24% increase in the rate of limitations in life support (Relative Hazard 1.24; 95% CI 1.11 to 1.40) after adjusting for daily ICU organ dysfunction score and all other covariates. Conclusions Older critically ill patients are more likely to have new limitations in life support independent of their baseline status, ICU-related severity of illness, and daily organ dysfunction status. Future studies are required to determine whether this association is a result of differences in patient preferences by age, or differences in the treatment options discussed with the families of older versus younger patients. PMID:24886945

2014-01-01

416

Acknowledging and Appreciating the Full Spectrum of the Human Condition: School Psychology's (Limited) Focus on Positive Psychological Functioning  

ERIC Educational Resources Information Center

This study is a content analysis of a random selection of 20% (N = 1,168) of articles from "School Psychology Quarterly", "Psychology in the Schools", the "Journal of School Psychology", and "School Psychology Review". Across the four journals, 27% of the articles had a positive focus, and the percentage of articles focused on the positive has…

Froh, Jeffrey J.; Huebner, E. Scott; Youssef, Al-Jameela; Conte, Vincent

2011-01-01

417

Toxicity study of cerium oxide nanoparticles in human neuroblastoma cells.  

PubMed

The present study consisted of cytotoxic, genotoxic, and oxidative stress responses of human neuroblastoma cell line (IMR32) following exposure to different doses of cerium oxide nanoparticles (CeO2 NPs; nanoceria) and its microparticles (MPs) for 24 hours. Cytotoxicity was evaluated by 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl tetrazolium bromide and lactate dehydrogenase assays whereas genotoxicity was assessed using the cytokinesis-block micronucleus and comet assays. A battery of assays including lipid peroxidation, reactive oxygen species (ROS), hydrogen peroxide, reduced glutathione, nitric oxide, glutathione reductase, glutathione peroxidase, superoxide dismutase, catalase, and glutathione S-transferase were performed to test the hypothesis that ROS was responsible for the toxicity of nanoceria. The results showed that nanosized CeO2 was more toxic than cerium oxide MPs. Hence, further study on safety evaluation of CeO2 NPs on other models is recommended. PMID:24510415

Kumari, Monika; Singh, Shailendra Pratap; Chinde, Srinivas; Rahman, Mohammed Fazlur; Mahboob, Mohammed; Grover, Paramjit

2014-01-01

418

Advantages and limitations of commercially available electrocuting grids for studying mosquito behaviour  

PubMed Central

Background Mosquito feeding behaviour plays a major role in determining malaria transmission intensity and the impact of specific prevention measures. Human Landing Catch (HLC) is currently the only method that can directly and consistently measure the biting rates of anthropophagic mosquitoes, both indoors and outdoors. However, this method exposes the participant to mosquito-borne pathogens, therefore new exposure-free methods are needed to replace it. Methods Commercially available electrocuting grids (EGs) were evaluated as an alternative to HLC using a Latin Square experimental design in Dar es Salaam, Tanzania. Both HLC and EGs were used to estimate the proportion of human exposure to mosquitoes occurring indoors (?i), as well as its two underlying parameters: the proportion of mosquitoes caught indoors (Pi) and the proportion of mosquitoes caught between the first and last hour when most people are indoors (Pfl). Results HLC and EGs methods accounted for 69% and 31% of the total number of female mosquitoes caught respectively and both methods caught more mosquitoes outdoors than indoors. Results from the gold standard HLC suggest that An. gambiae s.s. in Dar es Salaam is neither exophagic nor endophagic (Pi???0.5), whereas An. arabiensis is exophagic (Pi??>?0.5). EGs yielded estimates of Pi for An. gambiae s.s., An. arabiensis and An. coustani, that were approximately equivalent to those with HLC but significantly underestimated Pfl for An. gambiae s.s. and An. coustani. The relative sampling sensitivity of EGs declined over the course of the night (p???0.001) for all mosquito taxa except An. arabiensis. Conclusions Commercial EGs sample human-seeking mosquitoes with high sensitivity both indoors and outdoors and accurately measure the propensity of Anopheles malaria vectors to bite indoors rather than outdoors. However, further modifications are needed to stabilize sampling sensitivity over a full nocturnal cycle so that they can be used to survey patterns of human exposure to mosquitoes. PMID:23497704

2013-01-01

419

Animal models for studies on cold-induced platelet activation in human beings  

Microsoft Academic Search

When human platelets are chilled below about 20°C, they spontaneously activate, a phenomenon that limits their storage lifetime. We have previously shown that this activation in chilled human platelets is associated with passage through a lipid phase transition. Because animal models are necessary for investigating methods for cold storage of platelets, it is essential to determine whether such phase transitions

Fern Tablin; Naomi J Walker; Susan D Klein; Cara L Field; John H Crowe

2000-01-01

420

Virus-Free Human Placental Cell Lines To Study Genetic Functions  

Cancer.gov

These immortalized virus-free human placental cell lines expressing major proteins of human trophoblasts provide efficient in vitro models to study placental functions, control of tissue-specific gene expression, and other studies.