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Distribution by Scientific Domains

Life Sciences	35%
Medical Sciences	32%
Chemistry	11%
Earth and Environmental Science	8%
4 Other Domains	14%

Selected Abstracts

Relaxant effects of , -adrenergic agonists on porcine and human detrusor muscle

ACTA PHYSIOLOGICA, Issue 2 2005
J. K. Badawi
Abstract Aim:, Relaxant effects of different , -adrenoceptor agonists on porcine and human detrusor were examined. Thus, the , -adrenoceptor subtype mainly responsible for relaxation in the detrusor muscle of pigs was characterized. Additionally, different effects of several , -agonists in both species were shown. Methods:, Experiments were performed on muscle strips of porcine and human detrusor suspended in a tissue bath. The relaxant effects of the non-selective , -agonist isoprenaline, the selective ,2-agonists procaterol, salbutamol and the selective ,3-agonists BRL 37344, CL 316 243 and CGP 12177 on potassium-induced contraction were investigated. The inhibitory effect of different substances on the maximum contraction and the rank order of potency for endogenous catecholamines was determined in pigs. Furthermore, concentration-relaxation curves were performed for pigs and humans. Results:,Pigs: In the pre-treatment experiments isoprenaline and procaterol showed similar effects. The concentration,response experiments showed that the maximum relaxation induced by procaterol and salbutamol was more than 90%, not significantly different from isoprenaline, whereas the maximum relaxations of CL 316 243, BRL 37344 and CGP 12177 amounted to 68, 70 or 30%, respectively. Rank order of potencies was isoprenaline , adrenaline > noradrenaline. Humans: Isoprenaline, procaterol, salbutamol and CL 316 243 showed a maximum relaxation of 80, 41, 24 and 35% and pD2 values of 6.24, 5.65, 5.48 and 5.55, respectively. Conclusion:,,2-receptors play a main functional role in mediating relaxation of porcine detrusor. Selective ,2- and ,3-agonists similarly relax the human detrusor. Effects were smaller compared with the pig. [source]

Pharmacological and pharmacokinetic evaluation of celecoxib prodrugs in rats

BIOPHARMACEUTICS AND DRUG DISPOSITION, Issue 7 2002
Rao N.V.S. Mamidi
Abstract This study demonstrates the utility of an in vitro , in vivo correlative approach in the selection and optimization of a prodrug candidate of celecoxib (CBX), a COX2 inhibitor. As an initial screening step, a comparative single oral dose pharmacokinetic study was conducted in rats for CBX and its three aliphatic acyl water-soluble prodrugs viz., CBX-acetyl (CBX-AC), CBX-propionyl (CBX-PR) and CBX-butyryl (CBX-BU) at high equimolar dose, 100 mg/kg. Only CBX-BU and CBX-PR converted rapidly to CBX and yielded approximately five-fold greater systemic exposure of CBX than CBX alone or CBX-AC. Rank order of systemic exposure of prodrugs in its intact form was CBX-AC >CBX-PR >CBX-BU. Further in vitro hydrolysis studies of CBX prodrugs in intestinal mucosal suspensions and liver homogenates indicated that CBX-BU is rapidly and completely converted to CBX, whereas CBX-PR and CBX-AC require longer incubation period for complete conversion to CBX. There was a very good correlation of the in vitro and in vivo data supporting CBX-BU as the prodrug of choice. Further in vitro pharmacological studies showed that COX2 selective inhibition is improved for CBX-BU as compared to CBX-AC and CBX-PR. Dose proportionality in pharmacokinetic studies of CBX-BU and CBX at equimolar oral doses confirmed that relative oral bioavailability of CBX was improved following CBX-BU administration and there was linearity in pharmacokinetics of CBX over a wide dose range (10,100 mg/kg), whereas CBX in its conventional form showed poor bioavailability and lack of dose linearity in pharmacokinetics. The oral bioavailability of CBX from CBX-BU was dose independent and was in the range 78,96%. At a 50% reduced molar dose, CBX-BU showed an equivalent efficacy to that of CBX in the in vivo carrageenan model. Based on the study, water-soluble CBX-BU prodrug can be considered for clinical development in view of its potential advantages.Copyright © 2002 John Wiley & Sons, Ltd. [source]

Initialization Strategies in Simulation-Based SFE Eigenvalue Analysis

COMPUTER-AIDED CIVIL AND INFRASTRUCTURE ENGINEERING, Issue 5 2005
Song Du
Poor initializations often result in slow convergence, and in certain instances may lead to an incorrect or irrelevant answer. The problem of selecting an appropriate starting vector becomes even more complicated when the structure involved is characterized by properties that are random in nature. Here, a good initialization for one sample could be poor for another sample. Thus, the proper eigenvector initialization for uncertainty analysis involving Monte Carlo simulations is essential for efficient random eigenvalue analysis. Most simulation procedures to date have been sequential in nature, that is, a random vector to describe the structural system is simulated, a FE analysis is conducted, the response quantities are identified by post-processing, and the process is repeated until the standard error in the response of interest is within desired limits. A different approach is to generate all the sample (random) structures prior to performing any FE analysis, sequentially rank order them according to some appropriate measure of distance between the realizations, and perform the FE analyses in similar rank order, using the results from the previous analysis as the initialization for the current analysis. The sample structures may also be ordered into a tree-type data structure, where each node represents a random sample, the traverse of the tree starts from the root of the tree until every node in the tree is visited exactly once. This approach differs from the sequential ordering approach in that it uses the solution of the "closest" node to initialize the iterative solver. The computational efficiencies that result from such orderings (at a modest expense of additional data storage) are demonstrated through a stability analysis of a system with closely spaced buckling loads and the modal analysis of a simply supported beam. [source]

Influence of Temporal Scale of Sampling on Detection of Relationships between Invasive Plants and the Diversity Patterns of Plants and Butterflies

CONSERVATION BIOLOGY, Issue 6 2004
RALPH MAC NALLY
But monitoring is often neglected because it can be expensive and time-consuming. Accordingly, it is valuable to determine whether the temporal extent of sampling alters the validity of inferences about the response of diversity measures to environmental variables affected by restoration actions. Non-native species alter ecosystems in undesirable ways, frequently homogenizing flora and fauna and extirpating local populations of native species. In the Mojave Desert, invasion of salt-cedar (Tamarix ramosissima Ledeb.) and human efforts to eradicate salt-cedar have altered vegetation structure, vegetation composition, and some measures of faunal diversity. We examined whether similar inferences about relationships between plants and butterflies in the Muddy River drainage (Nevada, U.S.A.) could have been obtained by sampling less intensively (fewer visits per site over the same period of time) or less extensively (equal frequency of visits but over a more limited period of time). We also tested whether rank order of butterfly species with respect to occurrence rate (proportion of sites occupied) would be reflected accurately in temporal subsamples. Temporal subsampling did not lead to erroneous inferences about the relative importance of six vegetation-based predictor variables on the species richness of butterflies. Regardless of the temporal scale of sampling, the species composition of butterflies was more similar in sites with similar species composition of plants. The rank order of occurrence of butterfly species in the temporal subsamples was highly correlated with the rank order of species occurrence in the full data set. Thus, similar inferences about associations between vegetation and butterflies and about relative occurrence rates of individual species of butterflies could be obtained by less intensive or extensive temporal sampling. If compromises between temporal intensity and extent of sampling must be made, our results suggest that maximizing temporal extent will better capture variation in biotic interactions and species occurrence. Resumen:,El monitoreo es un componente importante de los esfuerzos de restauración y de manejo adoptivo. Pero el monitoreo a menudo es desatendido porque puede ser costoso y consume tiempo. En consecuencia, es valioso determinar si la extensión temporal del muestreo altera la validez de inferencias sobre la respuesta de medidas de diversidad a variables ambientales afectadas por acciones de restauración. Las especies no nativas alteran a los ecosistemas de manera indeseable, frecuentemente homogenizan la flora y fauna y extirpan poblaciones locales de especies nativas. En el Desierto Mojave, la invasión de Tamarix ramosissima Ledeb. y los esfuerzos humanos para erradicarla han alterado la estructura y composición de la vegetación y algunas medidas de diversidad de fauna. Examinamos si se podían obtener inferencias similares sobre las relaciones entre plantas y mariposas en la cuenca Muddy River (Nevada, E.U.A.) muestreando menos intensivamente (menos visitas por sitio en el mismo período de tiempo) o menos extensivamente (igual frecuencia de visitas pero sobre un período de tiempo más limitado). También probamos si el orden jerárquico de especies de mariposas con respecto a la tasa de ocurrencia (proporción de sitios ocupados) se reflejaba con precisión en las submuestras temporales. El submuestreo temporal no condujo a inferencias erróneas acerca de la importancia relativa de seis variables predictivas basadas en vegetación sobre la riqueza de especies de mariposas. A pesar de la escala temporal del muestreo, la composición de especies de mariposas fue más similar en sitios con composición de especies de plantas similar. El orden jerárquico de ocurrencia de especies de mariposas en las muestras subtemporales estuvo muy correlacionado con el orden jerárquico de ocurrencia de especies en todo el conjunto de datos. Por lo tanto, se pudieron obtener inferencias similares de las asociaciones entre vegetación y mariposas y de las tasas de ocurrencia relativa de especies individuales de mariposas con muestreo temporal menos intensivo o extensivo. Si se deben hacer compromisos entre la intensidad y extensión de muestreo temporal, nuestros resultados sugieren que la maximización de la extensión temporal capturará la variación en interacciones bióticas y ocurrencia de especies más adecuadamente. [source]

Relaxant effects of , -adrenergic agonists on porcine and human detrusor muscle

Viability of fibroblasts in a novel probiotic storage media

DENTAL TRAUMATOLOGY, Issue 5 2010
E Çaglar
The aim of the present in vitro study was to evaluate the number of viable PDL cells of avulsed teeth treated by Hank's Balanced Salt Solutions (HBSS), saline, a novel probiotic solution and milk. Thirty-six freshly extracted single-rooted human teeth with closed apices were divided into one of the four experimental groups and two control groups (N = 6 each). The positive and negative controls corresponded to 0 min and an 8-h dry time respectively. Following extraction, the coronal 3 mm of PDL tissue was scraped with a #15 scalpel to remove cells that might have been damaged. The experimental teeth were dried for 30 min followed by a 45 min immersion in one of the four experimental media. Each experimental tooth, after drying and soaking, was incubated for 30 min with a 2.5 ml solution of 0.2 mg ml,1 of collagenase CLS II and a 2.4 mg ml,1 solution of dispase grade II in phosphate buffer saline (PBS). The cells were then labelled with 0.4% Trypan blue for determination of viability. The teeth stored in positive control demonstrated the highest number of viable PDL cells followed in rank order by HBSS, saline, Lactobacillus reuteri solution and milk. There was no significant difference in the number of viable PDL cells between HBSS, milk, L. reuteri solution and saline. Within the parameters of this study, it appears that probiotic may be able to maintain PDL cell viability as HBSS, milk, or saline. [source]

DOES VARIATION IN SELECTION IMPOSED BY BEARS DRIVE DIVERGENCE AMONG POPULATIONS IN THE SIZE AND SHAPE OF SOCKEYE SALMON?

EVOLUTION, Issue 5 2009
Stephanie M. Carlson
Few studies have determined whether formal estimates of selection explain patterns of trait divergence among populations, yet this is one approach for evaluating whether the populations are in equilibria. If adaptive divergence is complete, directional selection should be absent and stabilizing selection should prevail. We estimated natural selection, due to bear predation, acting on the body size and shape of male salmon in three breeding populations that experience differing predation regimes. Our approach was to (1) estimate selection acting within each population on each trait based on an empirical estimate of reproductive activity, (2) test for trait divergence among populations, and (3) test whether selection coefficients were correlated with trait divergence among populations. Stabilizing selection was never significant, indicating that these populations have yet to attain equilibria. Directional selection varied among populations in a manner consistent with trait divergence, indicating ongoing population differentiation. Specifically, the rank order of the creeks in terms of patterns of selection paralleled the rank order in terms of size and shape. The shortest and least deep-bodied males had the highest reproductive activity in the creek with the most intense predation and longer and deeper-bodied males were favored in the creeks with lower predation risk. [source]

Inhibition of T-cell activation in vitro in human peripheral blood mononuclear cells by pimecrolimus and glucocorticosteroids and combinations thereof

EXPERIMENTAL DERMATOLOGY, Issue 8 2007
Anthony Winiski
Abstract:, Pimecrolimus is an ascomycin macrolactam derivative that has been recently approved for the topical treatment of atopic dermatitis. In this study we report for the first time on a direct comparison of the inhibitory activity of pimecrolimus and the glucocorticosteroids betamethasone 17-valerate, dexamethasone and hydrocortisone at the level of T-cell proliferation and cytokine production. Stimulated human peripheral blood mononuclear cell (PBMC) systems were used that are either sensitive or resistant to calcineurin inhibitors or glucocorticosteroids. Pimecrolimus and the glucocorticosteroids inhibited dose-dependently T-cell proliferation and cytokine production in a sensitive system (anti-CD3 mAb-stimulated PBMC) with the following rank order of potency: pimecrolimus , betamethasone 17-valerate , dexamethasone > hydrocortisone. In resistant systems (anti-CD3 plus anti-CD28- or Staphylococcal enterotoxin B-stimulated PBMC), pimecrolimus or the glucocorticosteroids alone exerted either no effect, or only a partial inhibitory effect. However, combinations of pimecrolimus with a glucocorticosteroid synergistically and strongly inhibited T-cell proliferation. Taken together, the data indicate that medium potency glucocorticosteroids, such as betamethasone 17-valerate and dexamethasone, are as potent T-cell inhibitors as pimecrolimus. Furthermore, the experimental evidence suggests that combinations of glucocorticosteroids and pimecrolimus could be used clinically to achieve superior therapeutic efficacy, when monotherapy with the individual agents is unsatisfactory. [source]

Comparison of operative procedure variables on pulpal viability in an ex vivo model

INTERNATIONAL ENDODONTIC JOURNAL, Issue 5 2008
P. E. Murray
Abstract Aim, To measure and compare the responses of pulp tissue to cavity preparation and restoration variables using a novel tooth slice culture model. Methodology, Experimental cavities (265) were continuously cut, under carefully controlled conditions, into the dentine of the labial aspect of 28-day-old Wistar rat incisors, and slices of these teeth maintained in organ culture for up to 2 weeks. The experimental variables examined were: the preparation method, remaining dentine thickness, coolant, drill speed, conditioning with EDTA and filling materials. The reactions of the dentine,pulp complex to the experimental variables were measured using pathohistometric analysis and the correlations between variables were determined using analysis of variance statistical tests. Results, In rank order of surgically induced restorative pulpal injury, from the most to the least injurious were: remaining dentine thickness, absence of coolant during cavity preparation, bur speed, cavity conditioning treatments and the filling material. Conclusions, To reduce pulp injury and to promote pulpal repair activity, the correct use of appropriate materials are important. However, of relatively greater importance is the operative technique adopted, the need to avoid the excess removal of dentine and to minimize trauma during preparation. [source]

Plant diversity and endemism in sub-Saharan tropical Africa

JOURNAL OF BIOGEOGRAPHY, Issue 2 2001
Linder
Aim This paper has as its central aim the location of centres of species richness and endemism in the sub-Saharan African flora. Previous postulation of these centres has been based on an intuitive interpretation of distributional data; this paper provides a test of these centres. A second aim is to establish whether the two indices, richness and endemism, locate the same centres. Thirdly the relationship between species richness and endemism, and latitude and rainfall are explored. Location The study area includes much of sub-Saharan Africa, but excludes the species-poor southern margin of the Sahara and the Namib,Kalahari regions. Methods Analyses were based on 1818 species, scored on a 2.5 × 2.5 degree grid. Species richness was inferred from a simple grid-diversity count; endemism was determined by three measures: the number of species restricted to two grids, the sum of the inverse of the ranges of the component species of each grid, and the proportion of the species in each grid that have restricted ranges. Results The African flora shows a remarkably profound patterning, both in species richness and endemism. The two measures locate largely the same centres, although the rank order among them differs. These centres are: the Cape Floristic Region, East Coast, Congo-Zambezi watershed, Kivu, Upper and Lower Guinea. Richness is strongly related to maximum rainfall, but there are no obvious correlations between modern climate and endemism. Species richness and endemism north of the equator is much more concentrated into centres than south of the equator. Main conclusions There are strongly developed refugia in sub-Saharan Africa. North of the equator, these refugia are sharply delimited and rather small, separated by large areas of very low endemism. South of the equator endemism tends to be more generally distributed. Variation in species richness in sub-Saharan Africa can be explained largely by modern rainfall, while endemism may be related to palaeoclimatic fluctuations. Both species richness and endemism show a strong skewing towards the south, indicating that the fluctuations in the Sahara might have influenced the modern distribution of plants in Africa. [source]

Does the perceived neighborhood reputation contribute to neighborhood differences in social trust and residential wellbeing?,

JOURNAL OF COMMUNITY PSYCHOLOGY, Issue 5 2010
Agneta Kullberg
The authors used a mixed methods approach to examine if the reputation of a housing area has bearing on residential wellbeing and social trust in three pairs of socioeconomically contrasting neighborhoods in a Swedish urban municipality. Multilevel logistic regression analyses were performed to examine associations between area reputation and residential wellbeing and social trust, controlling for the random effect of neighborhood and individual level sociodemographic factors. Qualitative data were analyzed to identify mechanisms of how neighborhood reputations were established. The housing area reputation was found to be strongly associated with wellbeing and social trust. The area reputation also seemed to be a determinant of position in the local social structure; residents were found to position themselves in a rank order. The results suggest that area reputation is an important and probably underestimated dimension in the development of residential wellbeing and social trust in housing. © 2010 Wiley Periodicals, Inc. [source]

Floral free fall in the Swiss lowlands: environmental determinants of local plant extinction in a peri-urban landscape

JOURNAL OF ECOLOGY, Issue 4 2007
IVANA STEHLIK
Summary 1Local floras are being depleted by a host of human activities, including habitat destruction and fragmentation, eutrophication, and the intensification of agriculture. Species with particular ecological demands or life-history attributes are more prone to extinction than species with a broader niche. 2We used an old herbarium from the municipality of Küsnacht (Swiss lowlands) as a historical record for comparison with contemporary plant diversity. This comparison revealed that 17% to 28% of all vascular plants that occurred between 1839 and 1915 were extinct by 2003. 3Species of different habitats and life-forms had significantly different rates of extinction: wetlands, disturbed sites and meadows lost most species, whereas forests and rocky habitats were least affected; aquatics and annuals were most prone to extinction, geophytes and hemicryptophytes were intermediate, and phanerophytes and chamaephytes were least affected. 4Species adapted to nutrient-poor soils suffered highest extinction in all habitats, indicating that eutrophication poses an urgent threat to species diversity. Light and soil moisture requirements also had significant effects on extinction, but the direction of the effect varied by habitat. 5When species were grouped into IUCN categories of the red list of Switzerland, the rank order of the observed extinction matched the red list assignment. 6Because many of the remaining species had high estimated extinction probabilities and because extinction is often delayed (extinction debt), a substantial part of the remaining flora of Küsnacht is likely to go extinct in the near future. This will increase the dominance of the common species that already comprise 81% of the local flora. 7The rates and patterns of extinction in Küsnacht are probably representative of surrounding Swiss lowlands and peri-urban landscapes in most developed countries. Studies such as ours can serve as a call for action and form a basis for future monitoring of biodiversity. [source]

Surface characterization of salmeterol xinafoate powders by inverse gas chromatography at finite coverage

JOURNAL OF PHARMACEUTICAL SCIENCES, Issue 3 2005
Henry H.Y. Tong
Abstract In our previous studies, surface analysis by inverse gas chromatography (IGC) at infinite dilution (zero coverage) was performed on four salmeterol xinafoate (SX) powdered samples, viz, two supercritical CO2 -processed Form I (SX-I) and Form II (SX-II) polymorphs, a commercial granulated SX (GSX) raw material and its micronized product (MSX). Both GSX and MSX are also of the same Form I polymorph. To further probe the differences in surface properties between the samples, the present study has extended the IGC analysis to the finite concentration range of selected energy probes. The adsorption isotherms of the SX samples were constructed using (nonpolar) octane, (polar acidic) chloroform, and (polar basic) tetrahydrofuran as liquid probes. Type II adsorption isotherms with weak knees were observed with each probe for all SX Form I samples. The extents of probe adsorption by the samples at various relative pressures follow the rank order: SX-II,>,GSX,,,MSX,>,SX-I, indicating that the SX-I has fewer high-energy adsorption sites than GSX and MSX. Type III isotherms were observed for SX-II with the two polar probes, indicative of weak adsorbate,adsorbent interactions. The additional information generated shows that IGC analysis at finite coverage is a valuable complementary tool to that at infinite dilution. © 2005 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 94:695,700, 2005 [source]

Oral peptide delivery: in-vitro evaluation of thiolated alginate/poly(acrylic acid) microparticles

JOURNAL OF PHARMACY AND PHARMACOLOGY: AN INTERNATI ONAL JOURNAL OF PHARMACEUTICAL SCIENCE, Issue 9 2007
Alexander Greimel
ABSTRACT The purpose of this study was to develop an oral thiomer-based microparticulate delivery system for insulin by ionic gelation. The microparticulate matrix consisted of either poly(acrylic acid)-cysteine (PAA-Cys) and alginate-cysteine (Alg-Cys) or the corresponding unmodified polymers (PAA, Alg). Two different viscosities of alginates were provided for the study, low and medium. Three different types of microparticles were prepared via ionic gelation with calcium (Alg, AlgPAA and AlgPAA-Cys) and their different properties evaluated in-vitro (particle size and shape, drug loading and release profile, swelling and stability). The mean particle size of all formulations ranged from 400 to 600 ,m, revealing the lowest for thiolated microparticles. SEM micrographs showed different morphological profiles for the three different types of microparticles. Encapsulation efficiency of insulin increased within the following rank order: Alg (15%) < AlgPAA (40%) < AlgPAA-Cys (65%). Alginate and AlgPAA microparticles displayed a burst release after 30 min, whereas the thiolated particles achieved a controlled release of insulin over 3 h. The swelling ratio was pH dependent: in simulated intestinal fluid microparticles exhibited a much higher water uptake compared with simulated gastric fluid. Due to the formation of intraparticulate disulfide bonds during the preparation process, thiolated particles revealed a higher stability. It was also observed that the viscosity of the two alginates used had no influence on the properties of the particles. According to these results AlgPAA-Cys microparticles obtained by ionic gelation and stabilized via disulfide bonds might be an alternative tool for the oral administration of therapeutic peptides. [source]

Trichothecene Content of Rye and Wheat Genotypes Inoculated with a Deoxynivalenol- and a Nivalenol-producing Isolate of Fusarium culmorum

JOURNAL OF PHYTOPATHOLOGY, Issue 5 2001
Miedaner
Head blight caused by Fusarium culmorum may lead to yield reduction and the contamination of cereal grain with the mycotoxins deoxynivalenol (DON), 3-acetyl deoxynivalenol (3-ADON), nivalenol (NIV), fusarenone-X (FUS), and others. In this study, the covariation between DON and NIV accumulation of 12 rye and eight wheat genotypes that differed in resistance were analysed by inoculating them with a DON-and a NIV-producing isolate, respectively, in three locations. The resistance traits head blight rating and plot yield relative to the uninoculated plots of the same genotype were assessed and the contents of DON, 3-ADON, NIV, and FUS in the grain were analysed by gas chromatography with mass spectrometry. The NIV-producing isolate was significantly (P=0.05) less aggressive and led to a considerably lower mean NIV content in the grain compared with the aggressiveness and mean DON content of the DON-producing isolate (19.5 mg NIV/kg grain versus 48.4 mg DON/kg). Wheat and rye genotypes significantly differed in their DON and NIV accumulation. All genotypes reacted in a similar manner to both chemotypes of F. culmorum for the resistance traits and the respective mycotoxin contents with the exception of one wheat variety, that caused a change in rank order for mycotoxin content. In conclusion, resistance to head blight and tolerance to mycotoxin accumulation seems to be most likely the same for DON- and NIV-producing isolates of F. culmorum. [source]

HOW WELL DOES THE 9-POINT HEDONIC SCALE PREDICT PURCHASE FREQUENCY?

JOURNAL OF SENSORY STUDIES, Issue 4 2005
M. ROSAS-NEXTICAPA
ABSTRACT One hundred and one consumers assessed three strawberry-flavored yogurts, using the 9-point hedonic scale and a purchase intent scale, both blind and with their appropriate cartons. They were then monitored for a year, to determine whether their ratings had any predictive value for their purchase behavior. It was found that the highest rated yogurts tended to be the ones that were purchased during the year. Any correspondence between rank order of rating and of purchase frequency was negligible. Predictions were better when the yogurts were rated with their cartons. The ratings were a better predictor of purchase frequency than price. Various consistency measures were also made. [source]

Genetic Correlations Between Initial Sensitivity to Ethanol and Brain cAMP Signaling in Inbred and Selectively Bred Mice

ALCOHOLISM, Issue 6 2001
Shelli L. Kirstein
Background: Several lines of evidence have suggested a role for cAMP (adenosine 3,,5,-cyclic monophosphate) signaling in the acute and chronic effects of ethanol. This study investigated whether there is a genetic correlation between cAMP synthesis in the brain and the acute effects of ethanol [alcohol sensitivity or acute functional tolerance (AFT)]. Methods: By using nine inbred strains of mice, we measured initial sensitivity and AFT to ethanol with a test of balance on a dowel. Initial sensitivity was defined by the blood ethanol concentration (BEC0) at the loss of balance on a dowel after an ethanol injection [1.75 g/kg intraperitoneally (ip)]. When mice were able to regain balance on the dowel, BEC1 was determined, and a second ethanol injection was given (2 g/kg ip). Upon final regaining of balance, BEC2 was determined. AFT was defined by the difference between BEC1 and BEC2 (AFT =,BEC = BEC2, BEC1). Cyclic AMP synthesis was measured in whole-cell preparations in the cerebellum and other brain areas of mice of the nine inbred strains. Results: Significant differences in BEC0 and AFT were seen among the mice of the nine inbred strains. Cerebellar basal and forskolin- and isoproterenol-stimulated cAMP production differed significantly between the strains, and BEC0 was found to correlate significantly with forskolin- and isoproterenol-stimulated cAMP accumulation in the cerebellum (r= 0.70 and 0.94, respectively). When we measured cAMP production in mesencephalic and telencephalic tissue in three strains of mice that differed significantly in isoproterenol-stimulated cAMP accumulation in the cerebellum, significant differences between strains were found only in telencephalic tissue. The relative relationship between the rank order of the three strains for cAMP accumulation in the telencephalon and initial sensitivity to ethanol was identical to that seen with the cerebellum. However, AFT did not correlate with cAMP accumulation in the cerebellum or any other brain area tested. Conclusions: These results suggest that cAMP-generating systems of the cerebellum and possibly the brain areas contained in telencephalic tissues (e.g., basal ganglia) may have an important relationship to an animal's initial sensitivity to the incoordinating effects of ethanol. [source]

The complexity of school and neighbourhood effects and movements of pupils on school differences in models of educational achievement

JOURNAL OF THE ROYAL STATISTICAL SOCIETY: SERIES A (STATISTICS IN SOCIETY), Issue 3 2009
George Leckie
Summary., Traditional studies of school differences in educational achievement use multilevel modelling techniques to take into account the nesting of pupils within schools. However, educational data are known to have more complex non-hierarchical structures. The potential importance of such structures is apparent when considering the effect of pupil mobility during secondary schooling on educational achievement. Movements of pupils between schools suggest that we should model pupils as belonging to the series of schools that are attended and not just their final school. Since these school moves are strongly linked to residential moves, it is important to explore additionally whether achievement is also affected by the history of neighbourhoods that are lived in. Using the national pupil database, this paper combines multiple membership and cross-classified multilevel models to explore simultaneously the relationships between secondary school, primary school, neighbourhood and educational achievement. The results show a negative relationship between pupil mobility and achievement, the strength of which depends greatly on the nature and timing of these moves. Accounting for pupil mobility also reveals that schools and neighbourhoods are more important than shown by previous analysis. A strong primary school effect appears to last long after a child has left that phase of schooling. The additional effect of neighbourhoods, in contrast, is small. Crucially, the rank order of school effects across all types of pupil is sensitive to whether we account for the complexity of the multilevel data structure. [source]

Multivariate exploratory analysis of ordinal data in ecology: Pitfalls, problems and solutions

JOURNAL OF VEGETATION SCIENCE, Issue 5 2005
János Podani
Abstract Questions: Are ordinal data appropriately treated by multivariate methods in numerical ecology? If not, what are the most common mistakes? Which dissimilarity coefficients, ordination and classification methods are best suited to ordinal data? Should we worry about such problems at all? Methods: A new classification model family, OrdClAn (Ordinal Cluster Analysis), is suggested for hierarchical and non-hierarchical classifications from ordinal ecological data, e.g. the abundance/dominance scores that are commonly recorded in relevés. During the clustering process, the objects are grouped so as to minimize a measure calculated from the ranks of within-cluster and between-cluster distances or dissimilarities. Results and Conclusions: Evaluation of the various steps of exploratory data analysis of ordinal ecological data shows that consistency of methodology throughout the study is of primary importance. In an optimal situation, each methodological step is order invariant. This property ensures that the results are independent of changes not affecting ordinal relationships, and guarantees that no illusory precision is introduced into the analysis. However, the multivariate procedures that are most commonly applied in numerical ecology do not satisfy these requirements and are therefore not recommended. For example, it is inappropriate to analyse Braun-Blanquet abudance/dominance data by methods assuming that Euclidean distance is meaningful. The solution of all problems is that the dissimilarity coefficient should be compatible with ordinal variables and the subsequent ordination or clustering method should consider only the rank order of dissimilarities. A range of artificial data sets exemplifying different subtypes of ordinal variables, e.g. indicator values or species scores from relevés, illustrate the advocated approach. Detailed analyses of an actual phytosociological data set demonstrate the classification by OrdClAn of relevés and species and the subsequent tabular rearrangement, in a numerical study remaining within the ordinal domain from the first step to the last. [source]

Cloning and pharmacological characterization of the equine adenosine A2A receptor: a potential therapeutic target for the treatment of equine endotoxemia

JOURNAL OF VETERINARY PHARMACOLOGY & THERAPEUTICS, Issue 4 2006
C. I. BRANDON
The aim of the current study was to clone the equine adenosine A2A receptor gene and to establish a heterologous expression system to ascertain its pharmacologic profile via radioligand binding and functional assays. An eA2A -R expression construct was generated by ligation of the eA2A cDNA into the pcDNA3.1 expression vector, and stably transfected into human embryonic kidney cells (HEK). Binding assays identified those clones expressing the eA2A -R, and equilibrium saturation isotherm experiments were utilized to determine dissociation constants (KD), and receptor densities (Bmax) of selected clones. Equilibrium competition binding revealed a rank order of agonist potency of ATL > CV-1808 > NECA > 2-CADO > CGS21680, and a rank order of antagonist potency as ZM241385 > 8-phenyltheophylline > p -sulfophenyltheophylline > caffeine. Furthermore, adenylate cyclase assays using selective A2A -R agonists revealed that the eA2A -R functionally coupled to G,s as indicated by an increase in intracellular [3H]cAMP upon receptor activation. Finally, NF- ,B reporter gene assays revealed a CGS21680 concentration-dependent inhibition of NF- ,B activity. These results indicate that the heterologously expressed eA2A -R has a pharmacological profile similar to that of other mammalian A2A receptors and thus can be utilized for further characterization of the eA2A -R to ascertain whether it can serve as a suitable pharmacological target for equine inflammatory disease. [source]

Diuretics: A modern day treatment option? (Review Article)

NEPHROLOGY, Issue 5 2006
MARTIN GALLAGHER
SUMMARY: The choice of drugs to initiate therapy for the management of hypertension remains contentious and diuretics are central to this controversy. Because most of the major trials involve complex treatment algorithms and allow diverse background treatments, one of the greatest challenges lies in separating out true class-specific effects , for example, separating true class-specific effects of diuretics from those of beta blockers. Despite these difficulties, the evidence confirms that diuretics are at least as effective as the newer first line groups in preventing cardiovascular events. The main area of doubt lies in relation to the risk of renal outcomes and of metabolic outcomes, such as new onset diabetes , where the evidence suggests that drugs that inhibit the renin-angiotensin system may be more protective than all other drug classes. These issues are reflected in the most recent international guidelines, all of which include diuretics among the first-line drugs for the treatment of hypertension, although they do differ on the role of diuretics in the initiation of therapy. Diuretics remain important for treating hypertension, especially in combination with other drug classes. The particular place of diuretics in the rank order of drugs must be tailored to suit the clinical situation in the individual patient. This will vary from a preferred option, as in black patients or elderly patients with systolic hypertension, to a second-line option in patients at high risk of developing new onset diabetes. [source]

More plant biomass results in more offspring production in annuals, or does it?

OIKOS, Issue 9 2008
Marina S. Neytcheva
Competitive ability in plants has been previously measured almost exclusively in terms of traits related to growth (biomass) or plant size. In this study, however, we used a multi-species competition experiment with six annuals to measure relative competitive ability in terms of reproductive output, i.e. the number of offspring produced for the next generation. Under greenhouse conditions, plants of each species were started in pots from germinating seeds and were grown singly (free of competition) and at high density in both monocultures and in mixtures with all study species. Several traits traditionally regarded as determinants of competitive ability in plants were recorded for each species grown singly, including: seed mass, germination time, early growth rate and potential plant size (biomass and height). Under competition, several traits were recorded as indicators of relative performance in both monocultures and mixtures, including: biomass of survivors, total number of survivors, number of reproductive survivors, and reproductive output (total seed production) of the survivors. As expected, species that grew to a larger biomass in isolation had higher seed production in isolation. However, none of the traditional plant growth/size-related traits, measured either in isolation or under competition, could predict between species variation in reproductive output under competition in either monocultures or mixtures. In mixtures, 97% of this variation in reproductive output could be explained by between-species variation in the number of reproductive survivors. The results indicate that traits measured on plants grown singly may be poor predictors of reproductive output under competition, and that species' rank order of competitive ability in terms of the biomass of survivors may bear no relationship to their rank order in terms of the number of offspring produced by these survivors. This has important implications for the interpretation of mechanisms of species coexistence and community assembly within vegetation. [source]

Assessing chimpanzee personality and subjective well-being in Japan

AMERICAN JOURNAL OF PRIMATOLOGY, Issue 4 2009
Alexander Weiss
Abstract We tested whether the cultural background of raters influenced ratings of chimpanzee personality. Our study involved comparing personality and subjective well-being ratings of 146 chimpanzees in Japan that were housed in zoos, research institutes, and a retirement sanctuary to ratings of chimpanzees in US and Australian zoos. Personality ratings were made on a translated and expanded version of a questionnaire used to rate chimpanzees in the US and Australia. Subjective well-being ratings were made on a translated version of a questionnaire used to rate chimpanzees in the US and Australia. The mean interrater reliabilities of the 43 original adjectives did not markedly differ between the present sample and the original sample of 100 zoo chimpanzees in the US. Interrater reliabilities of these samples were highly correlated, suggesting that their rank order was preserved. Comparison of the factor structures for the Japanese sample and for the original sample of chimpanzees in US zoos indicated that the overall structure was replicated and that the Dominance, Extraversion, Conscientiousness, and Agreeableness domains clearly generalized. Consistent with earlier studies, older chimpanzees had higher Dominance and lower Extraversion and Openness scores. Correlations between the six domain scores and subjective well-being were comparable to those for chimpanzees housed in the US and Australia. These findings suggest that chimpanzee personality ratings are not affected by the culture of the raters. Am. J. Primatol. 71:283,292, 2009. © 2009 Wiley-Liss, Inc. [source]

Dominance relationships among one-male units in a provisioned free-ranging band of the Sichuan snub-nosed monkeys (Rhinopithecus roxellana) in the Qinling Mountains, China

AMERICAN JOURNAL OF PRIMATOLOGY, Issue 7 2008
Peng Zhang
Abstract We studied the dominance relationships among one-male units (OMUs) in a provisioned free-ranging band of the Sichuan snub-nosed monkeys (Rhinopithecus roxellana) in the Qinling Mountains of central China from 2001 to 2005. The band was composed of 6,8 OMUs that stayed in the band for several years. Linear dominance orders could be detected using displacement interactions with directional asymmetry among OMUs in 82.3±5% of interactions, and ambiguous and reversed interactions in 17.7±5%. The dominance rank of OMUs was positively related with the duration of their stay in the band, and this may be attributed to the association of the resident male with adult females, rather than the fighting ability of resident males, as males do not fight seriously with each other. Subordinate units were observed to merge with dominant units resulting in an elevation of their rank order. The linear dominance relationship among OMUs in the Sichuan snub-nosed monkeys may have evolved as a result of competition for preferred food trees. Am. J. Primatol. 70:634,641, 2008. © 2008 Wiley-Liss, Inc. [source]

Cytokine stimulation and the choice of promoter are critical factors for the efficient transduction of mouse T cells with HIV-1 vectors

THE JOURNAL OF GENE MEDICINE, Issue 2 2010
David E. Gilham
Abstract Background HIV-1 fails to successfully infect mouse T cells as a result of several blocks in the viral replication cycle. We investigated whether this also impacted on the use of HIV-1 derived lentiviral vectors for stable gene transfer into mouse T cells. Methods Freshly isolated primary mouse T cells were immediately mixed with lentiviral vectors encoding an enhanced green fluorescent protein marker gene and transduction frequency was determined after 5 days of culture. Results Optimal transduction required both mouse T cell activation and cytokine support. Furthermore, transduction was also dependent upon the promoter chosen, with the rank order of potency being PGK > EF1 > SFFV > CMV. HIV-1 lentiviral vectors also efficiently transduced cytokine-stimulated T cells (in the absence of antibody driven T cell activation), albeit with a lower level of transgene expression compared to fully-activated T cells. Conclusions The present study demonstrates that primary mouse T cells can be efficiently transduced with HIV-1 lentiviral vectors, opening up prospects for their use in mouse models of gene-modified adoptive cellular therapy. Copyright © 2009 John Wiley & Sons, Ltd. [source]

The acute hypoxic ventilatory response under halothane, isoflurane, and sevoflurane anaesthesia in rats,

ANAESTHESIA, Issue 3 2010
N. Karanovic
Summary The relative order of potency of anaesthetic agents on the hypoxic ventilatory response has been tested in humans, but animal data are sparse. We examined the effects of 1.4, 1.6, 1.8, and 2.0 MAC halothane, isoflurane, and sevoflurane on phrenic nerve activity in euoxia (baseline) and during acute normocapnic hypoxia (inspired oxygen fraction 0.09) in adult male Sprague-Dawley rats. With halothane, all animals became apnoeic even in euoxia, and the hypoxic response was completely abolished at all anaesthetic levels. With isoflurane, 5 of 14 animals exhibited phrenic nerve activity in euoxia at 1.4 MAC and demonstrated a hypoxic response (302% of baseline activity), but all became apnoeic and lost the hypoxic response at higher doses. With sevoflurane, phrenic nerve activity and a hypoxic response was preserved in at least some animals at all doses (i.e. even the highest dose of 2.0 MAC). Similar to the rank order of potency previously observed in humans, the relative order of potency of depression of the hypoxic ventilatory response in rats was halothane (most depressive) > isoflurane > sevoflurane (p = 0.01 for differences between agents). [source]

Prediction of herbage yield in grassland: How well do Ellenberg N-values perform?

APPLIED VEGETATION SCIENCE, Issue 1 2007
Markus Wagner
Wisskirchen & Haeupler (1998) Abstract Question: How useful are Ellenberg N-values for predicting the herbage yield of Central European grasslands in comparison to approaches based on ordination scores of plant species composition or on soil parameters? Location: Central Germany (11°00,-11°37'E, 50°21-50°34'N, 500,840 m a.s.l.). Methods: Based on data from a field survey in 2001, the following models were constructed for predicting herbage yield in montane Central European grasslands: (1) Linear regression of mean Ellenberg N-, R- and F-values; (2) Linear regression of ordination scores derived from Non-metric Multidimensional Scaling (NMDS) of vegetation data; and (3) Multiple linear regression (MLR) of soil variables. Models were evaluated by cross-validation and validation with additional data collected in 2002. Results: Best predictions were obtained with models based on species composition. Ellenberg N-values and NMDS scores performed equally well and better than models based on Ellenberg R- or F-values. Predictions based on soil variables were least accurate. When tested with data from 2002, models based on Ellenberg N-values or on NMDS scores accurately predicted productivity rank order of sites, but not the actual herbage yield of particular sites. Conclusions: Mean Ellenberg N-values, which are easy to calculate, are as accurate as ordination scores in predicting herbage yield from plant species composition. In contrast, models based on soil variables may be useful for generating hypotheses about the factors limiting herbage yield, but not for prediction. We support the view that Ellenberg N-values should be called productivity values rather than nitrogen values. [source]

Enhancing a regional vegetation map with predictive models of dominant plant species in chaparral

APPLIED VEGETATION SCIENCE, Issue 1 2002
Janet Franklin
Abstract. Data from more than 900 vegetation plots surveyed in the evergreen shrublands of southern California were used to develop predictions of the distributions of eight dominant shrub species for a 3880 km2 region. The predictions, based on classification tree (CT) models, were validated using independent field data collected during a vegetation survey conducted in the 1930s. Presence and absence were correctly predicted an average of 75% of the time for the eight species. At the same time, these models minimized false positives, so that presence was predicted in the correct proportion of the cases for most species. The areal proportion of the landscape on which the species were predicted to occur was in the same rank order, and of the same magnitude, as their frequency (proportion of plots in which they occurred) within the field data sets. Predictive maps of species presence were overlaid and combined with an existing regional vegetation map. The shrub species ,assemblages' that resulted from this procedure had analogs with vegetation series defined using field data in previous studies. The resulting multiple species map will be used in a landscape simulation model of fire disturbance and succession. [source]

Toxicity and disruption of midgut physiology in larvae of the European corn borer, Ostrinia nubilalis, by anion transporter blockers

ARCHIVES OF INSECT BIOCHEMISTRY AND PHYSIOLOGY (ELECTRONIC), Issue 3 2009
Dhana Raj Boina
Abstract In this study, four blockers of anion transporters (ATs) belonging to four different classes of organic acids, including DIDS (4, 4'-diisothiocyanatostilbene-2, 2'- disulfonic acid; a stilbene disulfonic acid), NPPB [(5-nitro-2-(3-phenylpropylamino) benzoic acid; an anthranilic acid)], 9-AC (anthracene-9-carboxylic acid; an aromatic carboxylic acid), and IAA-94 (indanyloxy acetic acid; an indanyloxy alkanoic acid), were tested for their toxicity against the European corn borer (ECB), Ostrinia nubilalis. All the AT blockers inhibited the growth of larvae, increased the developmental time, and decreased survival compared to controls, when second-instar ECB larvae were fed for seven days on treated diet. In general, DIDS and NPPB were the most active compounds, with the rank order of activity being DIDS>NPPB>IAA-94>9-AC. All the AT blockers decreased the midgut alkalinity in fifth-instar larvae when fed for 3,h on treated diet. Effective concentrations required for 50% decrease in midgut alkalinity (EC50) ranged between 29.1 and 41.2,ppm and the rank order of activity was NPPB>DIDS>IAA-94>9-AC. Similarly, all the tested AT blockers inhibited 36Cl, uptake from the midgut lumen in fifth-instar larvae when fed for 3,h on treated diet. Concentrations required for 50% inhibition of 36Cl, uptake (IC50) ranged between 7.4 and 11.0,ppm and the rank order of activity was DIDS>NPPB>9-AC >IAA-94. Modest to highly strong positive correlations observed among growth, midgut alkalinity, and midgut Cl, ion transport in AT blocker,fed larvae suggested that these effects are causally related to each other. Finally, AT blockers have the potential to become good candidates for development of insecticides with a unique mode of action. © 2009 Wiley Periodicals, Inc. [source]

Image-based crystal detection: a machine-learning approach

ACTA CRYSTALLOGRAPHICA SECTION D, Issue 12 2008
Roy Liu
The ability of computers to learn from and annotate large databases of crystallization-trial images provides not only the ability to reduce the workload of crystallization studies, but also an opportunity to annotate crystallization trials as part of a framework for improving screening methods. Here, a system is presented that scores sets of images based on the likelihood of containing crystalline material as perceived by a machine-learning algorithm. The system can be incorporated into existing crystallization-analysis pipelines, whereby specialists examine images as they normally would with the exception that the images appear in rank order according to a simple real-valued score. Promising results are shown for 319,112 images associated with 150 structures solved by the Joint Center for Structural Genomics pipeline during the 2006,2007 year. Overall, the algorithm achieves a mean receiver operating characteristic score of 0.919 and a 78% reduction in human effort per set when considering an absolute score cutoff for screening images, while incurring a loss of five out of 150,structures. [source]