Particular Interest (particular + interest)

Distribution by Scientific Domains


Selected Abstracts


An Exact Test for the Association Between the Disease and Alleles at Highly Polymorphic Loci with Particular Interest in the Haplotype Analysis

BIOMETRICS, Issue 3 2001
Chihiro Hirotsu
Summary. The association analysis between the disease and genetic alleles is one of the simple methods for localizing the susceptibility locus in the genes. For revealing the association, several statistical tests have been proposed without discussing explicitly the alternative hypotheses. We therefore specify two types of alternative hypotheses (i.e., there is only one susceptibility allele in the locus, and there is an extension or shortening of alleles associated with the disease) and derive exact tests for the respective hypotheses. We also propose to combine these two tests when the prior knowledge is not sufficient enough to specify one of these two hypotheses. In particular, these ideas are extended to the haplotype analysis of three-way association between the disease and bivariate allele frequencies at two closely linked loci. As a by-product, a factorization of the probability distribution of the three-way cell frequencies under the null hypothesis of no three-way interaction is obtained. [source]


Development of the ecohydrological model SWIM for regional impact studies and vulnerability assessment

HYDROLOGICAL PROCESSES, Issue 3 2005
Valentina Krysanova
Abstract In this paper the ecohydrological model SWIM developed for regional impact assessment is presented, and examples of approaches to climate and land use change impact studies are described. SWIM is a continuous-time semi-distributed ecohydrological model, integrating hydrological processes, vegetation, nutrients (nitrogen and phosphorus) and sediment transport at the river basin scale. Its spatial disaggregation scheme has three levels: (1) basin, (2) sub-basins and (3) hydrotopes within sub-basins. The model was extensively tested and validated for hydrological processes, nitrogen dynamics, crop yield and erosion (mainly in mesoscale sub-basins of the German part of the Elbe River basin). After appropriate validation in representative sub-basins, the model can be applied at the regional scale for impact studies. Particular interest in the global change impact studies is given to effects of expected changes in climate and land use on hydrological processes and agro-ecosystems, including water balance components, water quality and crop yield. This paper (a) introduces the reader to the class of process-based ecohydrological catchment scale models, (b) introduces SWIM as one such model, and (c) presents two examples of impact studies performed with SWIM for the federal state of Brandenburg (Germany), which overlaps with the lowland part of the Elbe drainage area. The impact studies provide a better understanding of the complex interactions between climate, hydrological processes and vegetation, and improve our potential adaptation to the expected changes. Copyright © 2005 John Wiley & Sons, Ltd. [source]


How potential users of music search and retrieval systems describe the semantic quality of music

JOURNAL OF THE AMERICAN SOCIETY FOR INFORMATION SCIENCE AND TECHNOLOGY, Issue 5 2008
Micheline Lesaffre
A large-scale study was set up aiming at the clarification of the influence of demographic and musical background on the semantic description of music. Our model for rating high-level music qualities distinguishes between affective/emotive, structural and kinaesthetic descriptors. The focus was on the understanding of the most important attributes of music in view of the development of efficient search and retrieval systems. We emphasized who the users of such systems are and how they describe their favorite music. Particular interest went to inter-subjective similarities among listeners. The results from our study suggest that gender, age, musical expertise, active musicianship, broadness of taste and familiarity with the music have an influence on the semantic description of music. [source]


Compliance in small claims court: Exploring the factors associated with defendants' level of compliance with mediated and adjudicated outcomes

CONFLICT RESOLUTION QUARTERLY, Issue 2 2003
Jennie J. Long
This study explores how defendants in small claims cases, settled in either mediation or adjudication, react to case outcomes that require them to make some form of payment to the opposing party. Of particular interest was the relationship between dispute resolution forum and the reasons given for compliant behavior. Data were drawn from thirty-nine structured interviews in small claims cases filed in a local justice court. In mediated cases, defendants tended to comply with case outcomes from a sense of personal responsibility and obligation to fulfill a promise made to complainants, while defendants in adjudicated cases reported that they complied with the judgment in their case because of their duty to obey the law. [source]


Body Size and Risk of Extinction in Australian Mammals

CONSERVATION BIOLOGY, Issue 5 2001
Marcel Cardillo
For Australian terrestrial mammals this link is of particular interest because it is widely believed that species in the intermediate size range of 35,5500 g (the "critical weight range") have been the most prone to recent extinction. But the relationship between body size and extinction risk in Australian mammals has never been subject to a robust statistical analysis. Using a combination of randomization tests and phylogenetic comparative analyses, we found that Australian mammal extinctions and declines have been nonrandom with respect to body size, but we reject the hypothesis of a critical weight range at intermediate sizes. Small species appear to be the least prone to extinction, but extinctions have not been significantly clustered around intermediate sizes. Our results suggest that hypotheses linking intermediate body size with high risk of extinction in Australian mammals are misguided and that the focus of future research should shift to explaining why the smallest species are the most resistant to extinction. Resumen: El vínculo entre el tamaño del cuerpo y el riesgo de extinción ha sido el centro de mucha atención reciente. Para los mamíferos terrestres australianos este vínculo es de particular interés debido a que se cree ampliamente que las especies en un rango intermedio de tamaño de 35,5500 g (el rango de peso crítico) ha sido el más susceptible a extinciones recientes. Sin embargo, la relación entre extinciones, el tamaño y el riesgo de extinción en mamíferos australianos nunca ha sido sometida a un análisis estadístico robusto. Usando una combinación de pruebas aleatorizadas y análisis filogenéticos comparativos, encontramos que las extinciones y disminuciones de mamíferos australianos han sido no aleatorias con respecto al tamaño del cuerpo, pero rechazamos la hipótesis de un rango crítico a tamaños intermedios. Las especies pequeñas aparentan ser las menos susceptibles de extinción, pero las extinciones no se han agrupado significativamente alrededor de tamaños intermedios. Nuestros resultados sugieren que la hipótesis que vincula el tamaño intermedio de cuerpo con un alto riesgo de extinción en mamíferos australianos está mal planteada y que el centro de la investigación a futuro deberá enfocarse a explicar el porqué las especies más pequeñas son las más robustas a la extinción. [source]


Application of High Current and Current Zero Simulations of High-Voltage Circuit Breakers

CONTRIBUTIONS TO PLASMA PHYSICS, Issue 10 2006
C. M. Franck
Abstract This paper reports on the use of computational fluid dynamic (CFD) simulations to predict the interruption behaviour of high-voltage circuit breakers (HV-CB) using the self-blast principle. Two different levels of accuracy of the arc model are proven to be sufficiently accurate for simulating the high-current phase and the period around current zero (CZ). For the high-current phase, a simplified equivalent model of the arc is implemented to predict the pressure build-up, and even more important to accurately trace the hot gas from the arcing zone into the exhausts and the heating volume. A detailed analysis of the gas mixing in the heating volume for different arcing times and current amplitudes showed the optimum geometrical design of the heating volume. For the CZ phase, a more detailed arc model is needed including the effects of ohmic heating, radiative energy transfer, and turbulent cooling fully resolved in space and time. The validation with experiments was done and shows good agreement which justifies the use of the implemented model. With it, scaling laws varying only one parameter at a time (pressure and applied current slope) were derived and confirm previously found empirical laws. This is of particular interest, as it is very difficult to derive such scaling laws from experiments where the scatter is always very large and where it is impossible to vary only one parameter at a time. The influence of the most important geometrical parameters of the nozzle on the interruption performance is shown. In addition to previous experimental indications of this, the simulation reveals that turbulent cooling on the arc edge is the main reason for the difference in interruption performance. Moreover, the exact spatio-temporal build-up of arc resistance and with it the detailed understanding of the arc interruption process is possible and shown here for the first time. These simulations enable us to predict HV-CB performance and to minimise the number of development tests and are routinely used in new development projects. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]


The impact of operational characteristics on firms' EMS decisions: strategic adoption of ISO 14001 certifications

CORPORATE SOCIAL RESPONSIBILITY AND ENVIRONMENTAL MANAGEMENT, Issue 4 2010
Takuya Takahashi
Abstract Firms choose to seek environmental management system (EMS) certifications such as ISO 14001 for a variety of reasons. In this paper we put forward a hypothesis that firms seek ISO 14001 certifications for their establishments when their operations involve low degrees of complexity. Another hypothesis we consider is that firms facing more uncertainty in their operations (and hence more risk) seek ISO 14001 certifications. These hypotheses have not been yet addressed in the literature and are of particular interest to business managers and policymakers. We empirically test these hypotheses using probit and duration models using matched establishment,firm,industry data for large Japanese manufacturers. Our findings support the first as well as the second hypotheses. This suggests that firms tend to certify more routine and less complex operations first, and that firms use ISO 14001 certifications as an insurance scheme. Copyright © 2009 John Wiley & Sons, Ltd and ERP Environment. [source]


Dislocation cell structures in melt-grown semiconductor compound crystals

CRYSTAL RESEARCH AND TECHNOLOGY, Issue 1-2 2005
P. Rudolph
Abstract The phenomenon of dislocation patterning during melt growth of III-V, II-VI and IV-VI semiconductor crystals is discussed. The paper is focused on the formation of cellular structures driven by the growth inherent thermo-mechanical stress. Of particular interest is the scaling of relations between cells size, dislocation density and acting shear stress. Among the materials there are characteristic similarities but also significant variations of the cell genesis. After the related compound specifics are discussed possible measures for retardation of cell patterning during growth are demonstrated. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]


Limits to Democratic Development in Civil Society and the State: The Case of Santo Domingo

DEVELOPMENT AND CHANGE, Issue 1 2003
Anne Marie Choup
Some scholars see civil society as key to democratization of the political system. In this view, pressure from civil society forces democratization of the state. However, this disregards the fact that changes in civil society's behaviour require changes in political society , changes are reciprocal. The demand,making strategies of grassroots organizations in the Dominican Republic in 1999 provide a good example of this dynamic: the incomplete nature of the democratic transition (specifically, the persistence of paternalism and clientelism) constrained the democratic strategy choices of the civil society organizations. Just as democratization within political society is inconsistent and incomplete, so will be the demand,making strategies of the grassroots towards the state. The Dominican case is of particular interest as it illustrates the blend of personalized and institutionalized elements characteristic of democratic transition. [source]


Genetic analysis of early neurogenesis: Dedicated to the scientific contributions of Jose A. Campos-Ortega (1940,2004),

DEVELOPMENTAL DYNAMICS, Issue 7 2006
Volker Hartenstein
Abstract Jose Campos-Ortega stands out as one of the pioneers of developmental-genetic studies of early neurogenesis. He also liked to reflect about the history of science: how one discovery leads to the next, and what role individuals play in the progress of science. He had indeed started to work on a book describing the history of developmental genetics during the last year of his life. His goal in this book was to "explain how developmental genetics originated, how it transformed developmental biology and, while doing so, how it contributed to achieve the biological synthesis." In the following, I would like to reflect on the origin and growth of the field Campos-Ortega contributed so much. In doing so, it is of particular interest to consider his scientific roots, and the manner in which he entered the stage of developmental genetics. I believe that Campos-Ortega's unusual scientific background influenced in an important manner the way in which he shaped the study of early neurogenesis. Developmental Dynamics 235:2003,2008, 2006. © 2006 Wiley-Liss, Inc. [source]


Localization of Lutheran, a novel laminin receptor, in normal, knockout, and transgenic mice suggests an interaction with laminin ,5 in vivo

DEVELOPMENTAL DYNAMICS, Issue 1 2001
Casey L. Moulson
Abstract Laminins are major components of all basement membranes. One laminin that has garnered particular interest, due to its widespread expression pattern and importance during development, is the laminin ,5 chain. In vitro studies have suggested that the Lutheran blood group glycoprotein/basal cell adhesion molecule (Lu), an Ig superfamily transmembrane protein, is a receptor for laminins containing the ,5 chain. However, there are no in vivo studies showing that these proteins are capable of interacting in tissues. We have isolated the mouse ortholog of Lu and characterized its expression and localization in mouse tissues. Lu was primarily found on the basal surface of epithelial cells and on muscle cells adjacent to basement membranes containing laminin ,5. In addition, there was both a dramatic reduction in the basal concentration of Lu in mice lacking laminin ,5, and a significant increase in Lu protein in transgenic mice overexpressing laminin ,5. Together, these data provide the first in vivo evidence for an interaction between Lu and laminin ,5 and support the hypothesis that Lu is a laminin ,5 receptor. We propose that laminin ,5 is involved in concentrating Lu on the basal surface of epithelial cells. This may be one mechanism by which basement membrane signals are transmitted to the cell. © 2001 Wiley-Liss, Inc. [source]


Pyruvate dehydrogenase deficiency presenting as dystonia in childhood

DEVELOPMENTAL MEDICINE & CHILD NEUROLOGY, Issue 10 2004
R A Head MA
Two individuals with pyruvate dehydrogenase (PDH) deficiency due to missense mutations in the gene for the E1, subunit (PDHA1) presented during childhood with dystonia. The first patient, a male, presented at age 4 years with dystonia affecting the lower limbs, which responded to treatment with combined carbidopa and levodopa. The second patient, a female, was first investigated at age 6 years because of a dystonic gait disorder. In both patients, the main clue to the biochemical diagnosis was a raised concentration of lactate in the cerebrospinal fluid. PDH activity was significantly reduced in cultured fibroblasts in both cases. Dystonia is a previously unrecognized major manifestation of PDH deficiency and is of particular interest as the mutations in the PDHA1 gene in these patients have both been identified previously in individuals with typical presentations of the condition. [source]


Molecular mechanisms of insulin resistance

DIABETIC MEDICINE, Issue 6 2005
S. Schinner
Abstract Currently, we observe an epidemic expansion of diabetes mellitus. In subjects with Type 2 diabetes the resistance of fat, muscle and liver to insulin is the central pathophysiological event in the development of this disease. Genetic and environmental factors play a major role in this process, although the precise pathogenesis of insulin resistance and Type 2 diabetes is still largely unknown. However, recent studies have contributed to a deeper understanding of the molecular mechanisms underlying this process. In this review we therefore summarize the current developments in understanding the pathophysiological process of insulin resistance and Type 2 diabetes. Among the many molecules involved in the intracellular processing of the signal provided by insulin, insulin receptor substrate (IRS)-2, the protein kinase B (PKB)-, isoform and the forkhead transcription factor Foxo1a (FKHR) are of particular interest in this context as recent data have provided strong evidence that dysfunction of these proteins results in insulin resistance in-vivo. Furthermore, we have now increasing evidence that the adipose tissue not only produces free fatty acids that contribute to insulin resistance, but also acts as a relevant endocrine organ producing mediators (adipokines) that can modulate insulin signalling. The identification of the molecular pathophysiological mechanisms of insulin resistance and Type 2 diabetes is essential for the development of novel and more effective therapies to better treat our patients with insulin resistance and Type 2 diabetes. [source]


International survey on esophageal cancer: part II staging and neoadjuvant therapy

DISEASES OF THE ESOPHAGUS, Issue 3 2009
J. Boone
SUMMARY The outcome of esophagectomy could be improved by optimal diagnostic strategies leading to adequate preoperative patient selection. Neoadjuvant therapy could improve outcome by increasing the number of radical resections and by controlling metastatic disease. The purposes of this study were to gain insight into the current worldwide practice of staging modalities and neoadjuvant therapy in esophageal cancer, and to detect intercontinental differences. Surgeons with particular interest in esophageal surgery, including members of the International Society for Diseases of the Esophagus, the European Society of Esophagology , Group d'Etude Européen des Maladies de l'Oesophage, and the OESO, were invited to participate in an online questionnaire. Questions were asked regarding staging modalities, neoadjuvant therapy, and response evaluation applied in esophageal cancer patients. Of 567 invited surgeons, 269 participated resulting in a response rate of 47%. The responders currently performing esophagectomies (n= 250; 44%) represented 41 countries across the six continents. Esophagogastroscopy with biopsy and computed tomography (CT) scanning were routinely performed by 98% of responders for diagnosing and staging esophageal cancer, while endoscopic ultrasound (EUS) and barium esophagography were routinely applied by 58% and 51%, respectively. Neoadjuvant therapy is routinely administered by 33% and occasionally by 63% of responders. Of the responders that administer identical neoadjuvant regimens to esophageal adenocarcinoma (AC) and squamous cell carcinoma, 54% favor chemoradiotherapy. For AC, chemotherapy is preferred by 31% of the responders that administer neoadjuvant therapy, whereas for squamous cell carcinoma, the majority of responders (38%) prefer chemoradiotherapy. Response to neoadjuvant therapy is predominantly assessed by CT scanning of the chest and abdomen (86%). Barium esophagography, EUS, and combined CT/PET scan are requested for response monitoring in equal frequency (25%). Substantial differences in applied staging modalities and neoadjuvant regimens were detected between surgeons from different continents. In conclusion, currently the most commonly applied diagnostic modalities for staging and restaging esophageal cancer are CT scanning of the chest and abdomen, gastroscopy, barium esophagography and EUS. Neoadjuvant therapy is routinely applied by one third of the responders. Intercontinental differences have been detected in the diagnostic modalities applied in esophageal cancer staging and in the administration of neoadjuvant therapy. The results of this survey provide baseline data for future research and for the development of international guidelines. [source]


LBY135, a novel anti-DR5 agonistic antibody induces tumor cell,specific cytotoxic activity in human colon tumor cell lines and xenografts,

DRUG DEVELOPMENT RESEARCH, Issue 2 2008
Jing Li
Abstract TRAIL (TNF-related apoptosis-inducing ligand) induces apoptosis on binding to DR4 and DR5 receptors on the surface of tumor cells. These receptors are of particular interest in the development of cancer therapeutics as they preferentially mediate tumor cell apoptosis. We have generated a chimeric anti-DR5 agonistic antibody, LBY135, from its murine parental antibody, LCR211, identified using hybridoma technology. Both LCR211 and LBY135 specifically bind to DR5 with nanomolar affinity, mimic TRAIL to induce cell death in tumor cells, and have little effect on non-transformed cells in vitro. The anti-DR5 antibody reduced viability in 45% of a panel of 40 human colon cancer cell lines with IC50 values of 20,nM or less. In vivo, using human colorectal tumor xenograft mouse models, LCR211 induced tumor regression and showed enhanced efficacy when combined with 5-FU. Both in vitro evaluation of ADCC (antibody-dependent cell-mediated cytotoxicity) and CDC (complement-dependent cytotoxicity), and in vivo studies using a non-functional DR5 specific antibody or SCID-Beige mice, suggested ADCC and CDC are unlikely to be the mechanism to ablate tumors in vivo. LBY135 and LCR211 appear to mediate cell death and tumor regression mainly through apoptosis, as demonstrated by the activation of caspase 3, caspase 8, M30, and TUNEL assay. In addition, the discovery of synergy between cross-linked LBY135 and TRAIL not only revealed the unique epitope of LBY135, but also demonstrated an additional mechanism of action for LBY135 in vivo. LBY135 demonstrates promise as a novel therapeutic for cancer treatment and is currently in Phase I clinical trials. Drug Dev Res 69: 69,82, 2008. © 2008 Wiley-Liss, Inc. [source]


Echocardiographic Left Ventricular Mass in African-Americans

ECHOCARDIOGRAPHY, Issue 2 2003
The Jackson Cohort of the Atherosclerosis Risk in Communities Study
Characterization of target organ damage from hypertension is of particular interest in African-Americans, and evidence from electrocardiographic studies suggests that left ventricular hypertrophy is a frequent clinical finding of considerable prognostic importance. Echocardiographic studies may permit more precise characterization of the pathologic impact of hypertension on cardiac structure and function. The objective of this study is to characterize left ventricular (LV) structure including measures of wall thickness, septal thickness, internal dimension, and mass in a middle-aged sample of African-Americans using echocardiography. This study is a cohort (cross-sectional) study in which 2445 middle-aged African-American study participants from a population-based sample initially enrolled by the Atherosclerosis Risk in Communities, Jackson, Mississippi Examination Center in 1987,1989 underwent an M-mode echocardiograpic examination at their third or fourth clinic visit in 1993,1996. Measures of LV mass, even where indexed by size were conspicuously greater in men compared to women, and men exhibited a demonstrably steeper gradient of LV mass across the rather restricted age range of the study. However, when gender specific thresholds for LV hypertrophy were utilized, African-American men appear to have lower prevalence of LV hypertrophy than women. The lowest prevalence of LV hypertrophy was observed in African-American men who did not have hypertension (28.4%). The findings confirm previous suggestions from electrocardiographic investigations that cardiac hypertrophy is common, if not epidemic in middle-aged African-American men and women, whether or not they have hypertension. (ECHOCARDIOGRAPHY, Volume 20, February 2003) [source]


Rank and File: Assessing research quality in Australia

EDUCATIONAL PHILOSOPHY AND THEORY, Issue 7 2008
Linda J. Graham
Abstract In this paper, the author describes recent developments in the assessment of research activity and publication in Australia. Of particular interest to readers will be the move to rank academic journals. EPAT received the highest possible ranking, however the process is far from complete. Some implications for the field, for this journal and particularly, for the educational foundations are discussed. [source]


Electrophoresis on a microfluidic chip for analysis of fluorescence-labeled human rhinovirus

ELECTROPHORESIS, Issue 24 2007
Viliam Kolivo
Abstract We report the analysis of human rhinovirus serotype 2 (HRV2) on a commercially available lab-on-a-chip instrument. Due to lack of sufficient native fluorescence, the proteinaceous capsid of HRV2 was labeled with Cy5 for detection by the red laser (,ex 630,nm) implemented in the instrument. On the microdevice, electrophoresis of the labeled virus was possible in a BGE without stabilizing detergents, which is in contrast to conventional CE; moreover, analysis times were drastically shortened to the few 10,s range. Resolution of the sample constituents (virions, a contaminant present in all virus preparations, and excess dye) was improved upon adaptation of the separation conditions, mainly by adjusting the SDS concentration of the BGE. Purity of fractions from size-exclusion chromatography after labeling of virus was assessed, and affinity complex formation of the labeled virus with various recombinant very-low-density lipoprotein receptor derivatives differing in the number of concatenated V3 ligand binding repeats was monitored. Virus analysis on microchip devices is of particular interest for experiments with infectious material because of easy containment and disposal of samples. Thus, the employment of microchip devices in routine analysis of viruses appears to be exceptionally attractive. [source]


Proteomic mapping of the hyperthermophilic and acidophilic archaeon Sulfolobus solfataricus P2

ELECTROPHORESIS, Issue 14 2006
Richard C. Barry
Abstract A proteomic map of Sulfolobus solfataricus,P2, an archaeon that grows optimally at 80°C and pH,3.2, was developed using high-resolution 2-DE and peptide mass fingerprinting. A total of 867,protein spots (659,aqueous Tris-soluble spots and 208,aqueous Tris-insoluble) were mapped over IPG,3,10, 4,7, and 6,11, with second-dimensional gels made of 8,18%,polyacrylamide. Three hundred and twenty-four different gene products were represented by the 867,spots, with 274,gene products being identified in the Tris-soluble fractions and 100,gene products in the Tris-insoluble portion. Fifty gene products were found on gels from both fractions. Additionally, an average of 1.50 ± 0.12 isoforms/protein was identified. This mapping study confirmed the expression of proteins involved in numerous metabolic, transport, energy production, nucleic acid replication, translation, and transcription pathways. Of particular interest, phosphoenolpyruvate carboxykinase,(SSO2537) was detected even though the pathway for gluconeogenesis is unknown for this archaeon. Tris-soluble fractions contained many cytosolic proteins while Tris-insoluble fractions contained many membrane-associated proteins, including ABC transporters and an ATP synthase. This study provides an optimized 2-DE approach for investigating the biochemical pathways and post-translational modifications employed by Sulfolobus to survive in its extreme environment. [source]


Binding of ciprofloxacin by humic substances: A molecular dynamics study

ENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 1 2010
Ludmilla Aristilde
Abstract A comprehensive assessment of the potential impacts of antimicrobials released into the environment requires an understanding of their sequestration by natural particles. Of particular interest are the strong interactions of antimicrobials with natural organic matter (NOM), which are believed to reduce their bioavailability, retard their abiotic and biotic degradation, and facilitate their persistence in soils and aquatic sediments. Molecular dynamics (MD) relaxation studies of a widely used fluoroquinolone antibiotic, ciprofloxacin (Cipro), interacting with a model humic substance (HS) in a hydrated environment, were performed to elucidate the mechanisms of these interactions. Specifically, a zwitterionic Cipro molecule, the predominant species at circumneutral pH, was reacted either with protonated HS or deprotonated HS bearing Ca, Mg, or Fe(II) cations. The HS underwent conformational changes through rearrangements of its hydrophobic and hydrophilic regions and disruption of its intramolecular H-bonds to facilitate favorable intermolecular H-bonding interactions with Cipro. Complexation of the metal cations with HS carboxylates appeared to impede binding of the positively charged amino group of Cipro with these negatively charged HS complexation sites. On the other hand, an outer-sphere complex between Cipro and the HS-bound cation led to ternary Cipro,metal,HS complexes in the case of Mg,HS and Fe(II),HS, but no such bridging interaction occurred with Ca,HS. The results suggested that the ionic potential (valence/ionic radius) of the divalent cation may be a determining factor in the formation of the ternary complex, with high ionic potential favoring the bridging interaction. Environ. Toxicol. Chem. 2010;29:90,98. © 2009 SETAC [source]


Molecular modeling of metal complexation by a fluoroquinolone antibiotic

ENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 11 2008
Ludmilla Aristilde
Abstract An understanding of the factors controlling the chemodynamics of fluoroquinolone antibiotics in different environmental matrices is a necessary prerequisite to the assessment of their potential impact on nontarget organisms in soils and receiving waters. Of particular interest are the complexes formed between fluoroquinolones and metal cations, which are believed to be important in the mechanism of sequestration of the antibiotic by minerals and natural organic matter. The structures of these complexes have not been fully resolved by conventional spectroscopy; therefore, molecular simulations may provide useful complementary insights. We present results from apparently the first molecular dynamics simulations of a widely used fluoroquinolone antibiotic, ciprofloxacin (Cipro), in aqueous complexes with five metal cations typically found in soils and surface waters: Ca2+, Mg2+, Fe2+, Na+, and K+. The interatomic potential functions employed in the simulations were validated by comparison with available structural data for solid-phase Cipro-hexahydrate and for the metal cations in aqueous solution. Although no comprehensive structural data on the aqueous complexes appear to be available, properties of the metal complexes predicted by our simulations agree with available data for solid-phase metal,Cipro complexes. Our results indicate that the ionic potential of the metal cation controls the stability of the complex formed and that the hydration number of the metal cation in aqueous solution determines its coordination number with O atoms in the metal,Cipro complex. In respect to environmental chemodynamics, our results imply that Cipro will form two configurations of bidendate chelates with metal centers on exposed surfaces of mineral oxides, water-bridged surface complexes with exchangeable cations in clay mineral interlayers, and cation-bridged complexes with functional groups in natural organic matter. [source]


Plesiomorphic Escape Decisions in Cryptic Horned Lizards (Phrynosoma) Having Highly Derived Antipredatory Defenses

ETHOLOGY, Issue 10 2010
William E. Cooper Jr
Escape theory predicts that the probability of fleeing and flight initiation distance (predator,prey distance when escape begins) increase as predation risk increases and decrease as escape cost increases. These factors may apply even to highly cryptic species that sometimes must flee. Horned lizards (Phrynosoma) rely on crypsis because of coloration, flattened body form, and lateral fringe scales that reduce detectability. At close range they sometimes squirt blood-containing noxious substances and defend themselves with cranial spines. These antipredatory traits are highly derived, but little is known about the escape behavior of horned lizards. Of particular interest is whether their escape decisions bear the same relationships to predation risk and opportunity costs of escaping as in typical prey lacking such derived defenses. We investigated the effects of repeated attack and direction of predator turning on P. cornutum and of opportunity cost of fleeing during a social encounter in P. modestum. Flight initiation distance was greater for the second of two successive approaches and probability of fleeing decreased as distance between the turning predator and prey increased, but was greater when the predator turned toward than away from a lizard. Flight initiation distance was shorter during social encounters than when lizards were solitary. For all variables studied, risk assessment by horned lizards conforms to the predictions of escape theory and is similar to that in other prey despite their specialized defenses. Our findings show that these specialized, derived defenses coexist with a taxonomically widespread, plesiomorphic method of making escape decisions. They suggest that escape theory based on costs and benefits, as intended, applies very generally, even to highly cryptic prey that have specialized defense mechanisms. [source]


Effects of Market Segmentation and Bank Concentration on Mutual Fund Expenses and Returns: Evidence from Finland

EUROPEAN FINANCIAL MANAGEMENT, Issue 3 2004
Timo P. Korkeamaki
G15; G18; G20 Abstract A tremendous amount of research examines US mutual funds, but fund markets also thrive in other countries. However, research about these fast growing markets is lacking. This study addresses Finnish funds. Fast growth of the Finnish fund industry, strong bank dominance in the industry and recent EU membership make it an interesting market to examine. The Finnish fund market is also of particular interest since it had the fastest growth among the EU countries during 1996,2000. We find evidence that bank-managed and older funds charge higher expenses but investors are not compensated for paying higher expenses with higher risk-adjusted returns, suggesting a potential agency problem. Overall, Finnish fund expenses have decreased over time, consistent with EU membership reducing market segmentation and generating competition. [source]


Interleukin-4 downregulates CD127 expression and activity on human thymocytes and mature CD8+ T cells

EUROPEAN JOURNAL OF IMMUNOLOGY, Issue 5 2010
Angela M. Crawley
Abstract Signaling via the IL-7 receptor complex (IL-7R,/CD127 and IL-2R,/CD132) is required for T-cell development and survival. Decreased CD127 expression has been associated with persistent viral infections (e.g. HIV, HCV) and cancer. Many IL-2R,-sharing (,C) cytokines decrease CD127 expression on CD4+ and CD8+ T cells in mice (IL-2, IL-4, IL-7, IL-15) and in humans (IL-2, IL-7), suggesting a common function. IL-4 is of particular interest as it is upregulated in HIV infection and in thyroid and colon cancers. The role of IL-4 in regulating CD127 expression and IL-7 activity in human thymocytes and mature CD8+ T cells is unknown and was therefore investigated. IL-4 decreased CD127 expression on all thymocyte subsets tested and only on naïve (CD45RA+) CD8+ T cells, without altering membrane-bound CD127 mRNA expression. Pre-treatment of thymocytes or CD8+ T cells with IL-4 inhibited IL-7-mediated phosphorylation of STAT5 and decreased proliferation of CD8+ T cells. By downregulating CD127 expression and signaling on developing thymocytes and CD8+ T cells, IL-4 is a potential contributor to impaired CD8+ T-cell function in some anti-viral and anti-tumor responses. These findings are of particular consequence to diseases such as HIV, HCV, RSV, measles and cancer, in which CD127 expression is decreased, IL-7 activity is impaired and IL-4 concentrations are elevated. [source]


The Chemistry of Technetium,Water Complexes within the Manganese Triad: Challenges and Perspectives

EUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 1 2009
Roger Alberto
Abstract The chemistry of technetium is essentially driven by radiopharmaceutical applications. These comprise the syntheses of novel complexes but, moreover, the combination of targeting biomolecules with metal complexes. Aqua ions are especially convenient for facilitatating the introduction of metal cations into biomolecules, but are nonexistent for Tc and Re in the Mn triad. This microreview will discuss the chemistry of those Tc complexes that contain H2O as ligands. Special attention will be payed to organometallic aqua ions, i.e. complexes that are typically organometallic with water as ligand. Of particular interest is the coordination chemistry of [M(OH2)3(CO)3]+ (M = Mn, Tc, Re) complexes in water since it is the origin of the widely applied radiopharmaceutical research with 99mTc and 188Re. The chemistry of organometallic aqua ions is not confined to Werner-type ligands, hence, a further emphasis will be placed on pure organometallic chemistry in water.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009) [source]


Copper(I)-Assembled Pseudorotaxanes Bearing Bis(nitrile) Ligands: Selective Formation of Large Chelate Rings

EUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 3 2004
Efstathia G. Sakellariou
Abstract The syntheses of two novel CuI -bis(benzonitrile) complexes of the type [Cu(dCNn)2][PF6] {where dCNn = NCPhO(CH2)nOPhCN, n = 3, 4} are described. Both compounds have been characterized by X-ray crystallography. To our surprise, and although the two complexes were quite similar, two very distinct structures were obtained. For the [Cu(dCN4)2][PF6] complex, a tetrahedral geometry was observed whereas for [Cu(dCN3)2][PF6], a polymeric assembly was formed. A further extension of this work involved the syntheses of two threaded species bearing the M30 macrocycle, Cu metal and a dCNn ligand. The formation of the desired complexes was confirmed by means of mass spectrometry as well as 1-D and 2-D 1H NMR spectroscopy. Finally, the cyclic voltammograms of all 4 new species were recorded giving rise to redox potentials ranging from +0.88 to +1.25 V. These new threaded complexes are of particular interest since they can form the basis of novel rotaxane structures. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004) [source]


Neurochemical identification of stereotypic burst-firing neurons in the rat dorsal raphe nucleus using juxtacellular labelling methods

EUROPEAN JOURNAL OF NEUROSCIENCE, Issue 1 2007
Mihály Hajós
Abstract Recent electrophysiological studies have discovered evidence of heterogeneity of 5-hydroxytryptamine (5-HT) neurons in the mesencephalic raphe nuclei. Of particular interest is a subpopulation of putative 5-HT neurons that display many of the electrophysiological properties of presumed 5-HT-containing neurons (regular and slow firing of single spikes with a broad waveform) but fire spikes in short, stereotyped bursts. In the present study we investigated the chemical identity of these neurons in rats utilizing in vivo juxtacellular labelling methods. Of ten dorsal raphe nucleus (DRN) neurons firing short stereotyped bursts within an otherwise regular firing pattern, all exhibited immunoreactivity for either 5-HT (n = 6) or the 5-HT synthesizing enzyme, tryptophan hydroxylase (TRH; n = 2) or both (n = 2). Supporting pharmacological experiments demonstrated that the burst firing DRN neurons demonstrated equal sensitivity to 5-HT1A agonism and ,1 -adrenoceptor antagonism to single spiking DRN neurons that we have previously identified as 5-HT-containing. Collectively these data provide direct evidence that DRN neurons that exhibit stereotyped burst firing activity are 5-HT containing. The presence of multiple types of electrophysiologically distinct midbrain 5-HT neurons is discussed. [source]


Sol,Gel Derived Nanocomposites for Optical Applications

ADVANCED ENGINEERING MATERIALS, Issue 5 2010
Peter W. de Oliveira
This paper provides a selective description of the development of nanostructured materials and the fabrication of the devices for optical applications. Examples are interference coatings, refractive and diffractive lenses, and macro- and micro-GRIN (graded refractive index) optical elements. Hybrid materials containing nanoparticles are of particular interest for the production of optical elements because, by exploiting the intrinsic solid state properties of the nanoparticles, nanocomposites can be tailored to exhibit the desired properties. A particular advantage of wet chemical processing lies in its great flexibility for depositing functional coatings. [source]


Regulation of miRNA expression during neural cell specification

EUROPEAN JOURNAL OF NEUROSCIENCE, Issue 6 2005
Lena Smirnova
Abstract MicroRNA (miRNA) are a newly recognized class of small, noncoding RNA molecules that participate in the developmental control of gene expression. We have studied the regulation of a set of highly expressed neural miRNA during mouse brain development. Temporal control is a characteristic of miRNA regulation in C. elegans and Drosophila, and is also prominent in the embryonic brain. We observed significant differences in the onset and magnitude of induction for individual miRNAs. Comparing expression in cultures of embryonic neurons and astrocytes we found marked lineage specificity for each of the miRNA in our study. Two of the most highly expressed miRNA in adult brain were preferentially expressed in neurons (mir-124, mir-128). In contrast, mir-23, a miRNA previously implicated in neural specification, was restricted to astrocytes. mir-26 and mir-29 were more strongly expressed in astrocytes than neurons, others were more evenly distributed (mir-9, mir-125). Lineage specificity was further explored using reporter constructs for two miRNA of particular interest (mir-125 and mir-128). miRNA-mediated suppression of both reporters was observed after transfection of the reporters into neurons but not astrocytes. miRNA were strongly induced during neural differentiation of embryonic stem cells, suggesting the validity of the stem cell model for studying miRNA regulation in neural development. [source]


5,7-dihydroxytryptamine lesions enhance and serotonergic grafts normalize the evoked overflow of acetylcholine in rat hippocampal slices

EUROPEAN JOURNAL OF NEUROSCIENCE, Issue 10 2002
Anja Birthelmer
Abstract Adult rats were subjected to intracerebroventricular injections of 5,7-dihydroxytryptamine (5,7-DHT; 150 µg) and, 15 days later, to intrahippocampal grafts of fetal raphe cell suspensions. About 11 months later, we assessed baseline and electrically evoked release of tritium ([3H]) in hippocampal slices, preloaded with tritiated ([3H])choline or [3H]serotonin (5-HT), in the presence or absence of the 5-HT1B receptor agonist CP-93,129 and the 5-HT receptor antagonist methiothepine. HPLC determinations of monoamine concentrations were also performed. The lesions reduced the concentration of 5-HT (,90%) and the accumulation (,80%) as well as the evoked release (,90%) of [3H]5-HT. They also decreased the inhibitory effects of CP-93,129 on the evoked release of [3H]5-HT. Most interestingly, they facilitated the evoked release of [3H]acetylcholine (+20%). In slices from rats subjected to lesions and grafts, the responsiveness of the serotonergic autoreceptors (presumably located on the terminals of the grafted neurons) and the release of acetylcholine were close to normal. These results confirm that grafts rich in serotonergic neurons may partially compensate for the dramatic effects of 5,7-DHT lesions on serotonergic hippocampal functions. The lesion-induced reduction of the 5-HT1B autoreceptor-mediated inhibition of evoked 5-HT release may be an adaptation enhancing serotonergic transmission in the (few) remaining terminals. The facilitated release of acetylcholine is probably caused by a reduced serotonergic tone on the inhibitory 5-HT1B heteroreceptors of the cholinergic terminals. When related to data in the literature, this facilitation may be of particular interest in terms of transmitter-based strategies developed to tackle cognitive symptoms related to neurodegenerative diseases. [source]