bluuebunny/crossref_metadata_2025 huggingface dataset:
Deciphering the role of glucosamine-6-phosphate in the riboswitch action of glmS ribozyme
Authors: Xin Yao , Hamelberg Donald
Published: October 2010

The GlmS ribozyme is believed to exploit a general acid-base catalytic mechanism in the presence of glucosamine-6-phosphate (GlcN6P) to accelerate self-cleavage by approximately six orders of magnitude. The general acid and general base are not known, and the role of the GlcN6P cofactor is even less well understood. The amine group of GlcN6P has the ability to either accept or donate a proton and could therefore potentially act as an acid or a base. In order to decipher the role of GlcN6P in the self-cleavage of glmS, we have determined the preferred protonation state of the amine group in the wild-type and an inactive G40A mutant using molecular dynamics simulations and free energy calculations. Here we show that, upon binding of GlcN6P to wild-type glmS, the pKa of the amine moiety is altered by the active site environment, decreasing by about 2.2 from a solution pKa of about 8.2. On the other hand, we show that the pKa of the amine group slightly increases to about 8.4 upon binding to the G40A inactive mutant of glmS. These results suggest that GlcN6P acts as a general acid in the self-cleavage of glmS. Upon binding to glmS, GlcN6P can easily release a proton to the 5′-oxygen of G1 during self-cleavage of the backbone phosphodiester bond. However, in the G40A inactive mutant of glmS, the results suggest that the ability of GlcN6P to easily release its proton is diminished, in addition to the possible lack of G40 as an effective base.
Control of translation efficiency in yeast by codon–anticodon interactions
Authors: Letzring Daniel P. , Dean Kimberly M. , Grayhack Elizabeth J.
Published: October 2010

The choice of synonymous codons used to encode a polypeptide contributes to substantial differences in translation efficiency between genes. However, both the magnitude and the mechanisms of codon-mediated effects are unknown, as neither the effects of individual codons nor the parameters that modulate codon-mediated regulation are understood, particularly in eukaryotes. To explore this problem in Saccharomyces cerevisiae, we performed the first systematic analysis of codon effects on expression. We find that the arginine codon CGA is strongly inhibitory, resulting in progressively and sharply reduced expression with increased CGA codon dosage. CGA-mediated inhibition of expression is primarily due to wobble decoding of CGA, since it is nearly completely suppressed by coexpression of an exact match anticodon-mutated tRNAArg(UCG), and is associated with generation of a smaller RNA fragment, likely due to endonucleolytic cleavage at a stalled ribosome. Moreover, CGA codon pairs are more effective inhibitors of expression than individual CGA codons. These results directly implicate decoding by the ribosome and interactions at neighboring sites within the ribosome as mediators of codon-specific translation efficiency.
Organizing for Product Development Across Technological Environments: Performance Trade-offs and Priorities
Authors: Cardinal Laura B. , Turner Scott F. , Fern Michael J. , Burton Richard M.
Published: October 2010

This study examines how designing for product development influences project performance in distinct technological environments. Drawing on a series of computational experiments and paired-case comparisons of six product development projects, we specifically examine how new product development performance is affected by project design and the technological environment. By triangulating across the computational experiments and case studies, we find the existence of performance trade-offs in product development as well as the importance of performance priorities in influencing project design. These findings permit us to elaborate on existing contingency-based perspectives of new product development and put forward a novel mediating model. In this mediating model of product development, we suggest that the technological environment shapes performance priorities, which in turn influence project design and ultimately the performance outcomes of new product development efforts. This model further highlights that project designs can evolve as a function of performance outcomes, although this process can be inhibited by the presence of design evolution constraints. This research contributes significantly to our understanding of designing projects for new product development.
Contacts and Contracts: Cross-Level Network Dynamics in the Development of an Aircraft Material
Authors: Berends Hans , van Burg Elco , van Raaij Erik M.
Published: October 2010

In this paper, we investigate how interorganizational networks and interpersonal networks interact over time. We present a retrospective longitudinal case study of the network system that developed a novel aircraft material and analyze change episodes from a structurationist perspective. We identify five types of episodes in which interpersonal and interorganizational networks interact (persistence, prospecting, consolidation, reconfiguration, and dissolution) and analyze conditions for these episodes and sequences among them. Our findings advance a cross-level perspective on embeddedness and show how individuals may draw on relational and structural embeddedness as distributed resources. The multiple levels of embeddedness impact network dynamics by introducing converging and diverging dialectics, thereby limiting path dependence and proactive network orchestration.
The Organizational Selection of Status Characteristics: Status Evaluations in an Open Source Community
Authors: Bianchi Alison J. , Kang Soong Moon , Stewart Daniel
Published: October 2010

Organizations mediate societal cultural belief systems and group-level encounters by filtering, and sometimes transforming, social information regarding which status characteristics are salient during group encounters embedded within organizations. This study uses status characteristics theory to add to our understanding of social status within organizations by explaining why organizations matter in determining which status characteristics will be activated within task groups. By analyzing status rankings within an organization of open source software programmers, we find that the organization develops its own unique shared belief system, which inculcates actors with beliefs about status characteristics that are potentially unique within the boundaries of the organization. Specifically, in this study we find that through a process of status generalization, organizational members create new status markers (location) that are potentially only meaningful for the given social situation, and they selectively nullify others (education and age). To the best of our knowledge, the current study is the first work in the expectation states tradition to demonstrate an outcome for an organization-level selection process for status characteristics. This paper adds to status characteristics theory by empirically analyzing how organizational contexts create boundaries around groups in which new and extant status characteristics are activated and in which predefined characteristics inherited from more global, society-level contexts are deactivated.
Foundations of Organizational Trust: What Matters to Different Stakeholders?
Authors: Pirson Michael , Malhotra Deepak
Published: October 2010

Prior research on organizational trust has not rigorously examined the context specificity of trust nor distinguished between the potentially varying dimensions along which different stakeholders base their trust. As a result, dominant conceptualizations of organizational trust are overly generalized. Building on existing research on organizational trust and stakeholder theory, we introduce a more nuanced perspective on the nature of organizational trust. We develop a framework that distinguishes between organizational stakeholders along two dimensions: depth of the relationship (deep or shallow) and locus (internal or external). The framework identifies which of six dimensions of trustworthiness (benevolence, integrity, managerial competence, technical competence, transparency, and identification) will be relevant to which stakeholder type. We test the predictions of our framework using original survey data from 1,298 respondents across four stakeholder groups from four different organizations. The results reveal that the relevant dimensions of trustworthiness vary systematically across different stakeholder types and provide strong support for the validity of the depth and locus dimensions.
The Coevolution of Network Ties and Perceptions of Team Psychological Safety
Authors: Schulte Mathis , Cohen N. Andrew , Klein Katherine J.
Published: October 2010

Which comes first—team social networks or emergent team states (e.g., team climate)? We argue that team members' social network ties and team members' climate perceptions coevolve over time as a function of six reciprocal and co-occurring processes. We test our conceptual framework in a 10-month longitudinal study of perceptions of team psychological safety and social network ties in 69 work teams and find considerable support for our hypotheses. Our main results suggest that perceptions of psychological safety predict network ties. The more psychologically safe team members perceive their team to be, the more likely they are to ask their teammates for advice and to see them as friends, and the less likely they are to report difficult relationships with them. At the same time, network ties predict psychological safety. Team members adopt their friends' and advisors' perceptions of the team's psychological safety and reject the perceptions of those with whom they report a difficult relationship. Our framework and findings suggest that conceptual models and tests of unidirectional or team-level effects are likely to substantially misrepresent the mechanisms by which network ties and emergent team states coevolve.
Zeolite-modified electrodes with analytical applications
Authors: Muresan Liana Maria
Published: October 2010

Zeolite-modified electrodes (ZMEs) have been widely investigated because of their chemical, physical, and structural characteristics (shape, size, and charge selectivities; physical and chemical stabilities; high ion-exchange capacity; hydrophilic character; etc.), which make them of high interest in the design of electroanalytical systems. The paper presents recent literature data about fundamental and practical aspects related to the obtaining and applications of ZMEs. Some new ZMEs based on carbon paste incorporating soluble pheno-thiazinic dyes adsorbed on X-type zeolites are assessed comparatively, and the influence of some experimental parameters on the electrochemical response of these electrodes was investigated. The kinetic parameters for the heterogeneous electron-transfer process corresponding to the surface-immobilized mediators were determined, and all observed differences were used as evidence of the influence of the mediator structure and of the zeolite nature on the electrochemical activity of the new electrodes and on their electrocatalytic properties toward β-nicotinamide adenine dinucleotide (NADH) or ascorbic acid (AA) electro-oxidation and H2O2 electroreduction.
Psychotherapists' practices in keeping a session 'on-track' in the face of clients' "off-track" talk
Authors: Antaki Charles , Jahoda Andrew
Published: October 2010

Based on an inspection of sessions with intellectually impaired and non-impaired clients, five conversational practices are identified by which a cognitive behaviour psychotherapist may keep the session "on-track" in the face of possible deviation. Close inspection of audio- and video-recordings reveals a gradient of therapist responses. They range between minimal receipt of what the client has said, even when this would otherwise have warranted expansion, all the way to explicit active topic shift which takes a more directive role. The operation of these topic-management practices is explained using Conversation Analysis, and their therapeutic utility and possible dangers are outlined. The article ends with a brief sketch of the tension between an "outsider's" Conversation-Analysis perspective on the organisation of therapy talk, and a therapist's, "insider's", view of the meanings and intentions of what participants say.
The negotiation of the problem statement in Cognitive Behavioural Therapy
Authors: Beckwith Andrew , Crichton Jonathan
Published: October 2010

Cognitive behavioural therapy (CBT) is a form of psychotherapy which is characterized by being highly structured, outcomes focused and time limited. The literature concerning CBT is extensive but it has primarily focused on the outcomes of therapy with limited qualitative studies investigating the process of CBT. In this present study we investigate how the CBT model is implemented in therapeutic interaction through a focus on the conversion of the client's problem into CBT terms and its ultimate articulation as the problem statement. The problem statement is an integral part of the form of CBT studied from which the subsequent therapy is derived. Drawing on theme-oriented discourse analysis we examine the first two sessions of the treatment of one client using a number of tools derived from discourse and conversation analysis. This case study was drawn from a larger corpus of the CBT treatment of ten clients. The expertise of the therapist in applying the generic CBT model of therapy to the client's particular problem is a focus of this study.
The long-term impact of a communication course for doctors and nurses: The parents’ perspective
Authors: Ammentorp Jette , Kofoed Poul-Erik
Published: October 2010

The objective of the study is to investigate the longterm effect of a training course in communication for doctors and nurses. In pre- and post-design, we investigated the effect of Maguire's communication course. Parents’ perceptions of the communications with the clinicians were monitored continuously for up to three years following the course using electronic questionnaires. Two hundred and seventy-one responses were obtained from the parents in 2004 (65%), 3712/4875 in 2006 (76%), and 3033/4395 in 2007 (69%). After the course, the proportion of satisfied parents increased significantly. The greatest improvements occurred in response to the statement: ‘The clinician tried to understand how I experienced the problem’ (OR: 6.4 and 6.3). There was no association between the time since the clinician had participated in the course and the mean score of the perceived communication and satisfaction. In conclusion parents’ perceptions of communication improved significantly after the department implemented a communication program, and remained unchanged for up to three years. Electronic and continuous monitoring of quality of care is an appropriate method to evaluate new initiatives, such as training courses.
Problem perception in Dutch university students using tobacco, alcohol and drugs
Authors: Boot Cecile R.L. , Meijman Frans J. , Vonk Peter
Published: October 2010

When communicating about health behaviour with students, insight is needed in perceptions students have about their (un)healthy behaviour. We aimed to investigate associations between problem perception and perceived health, academic functioning in students using tobacco, alcohol or drugs. Students who were enrolled fulltime in Medicine, Economics, Occupational Therapy, History, Psychology or Information Studies in Amsterdam, the Netherlands (n = 8258), were invited for an internet-based questionnaire about perceived health, social support, study delay, and problem perception regarding tobacco, alcohol and drug use in October 2005 (response: 44%). Students using tobacco, alcohol and drugs with and without problem perception and non-users were compared (logistic regression). Problem perception in students using tobacco, alcohol or drugs was associated with worse health outcomes.
‘These psychiatrists rate themselves as gods’: Disengagement and engagement discourses of people living with severe mental illness
Authors: Chase Mike , Zinken Jörg , Costall Alan , Watts Jay , Priebe Stefan
Published: October 2010

Positioning analysis, a variant of discourse analysis, was used to explore the narratives of 40 psychiatric patients (11 females and 29 males; mean age = 40 years) who had manifest difficulties with engagement with statutory mental health services. Positioning analysis is a qualitative method that captures how people linguistically position the roles and identities of themselves and others in their day-to-day lives and narratives. The language of disengagement incorporated the passive positioning of self in relation to their lives and treatment through the use of metaphor, the passive voice and them and us attribution, while the discourse of engagement incorporated more active positioning of self, achieved through the use of the personal pronoun we and metaphoric references to balanced relationships. The findings corroborate previous thematic analysis that highlighted the importance of identity and agency in the ‘making or breaking’ of therapeutic relationships (Priebe et al. 2005). Implications are discussed in relation to how positioning analysis may help signal and emphasize important life and therapeutic experiences in spoken narratives as well as clinical consultations.
Accounts of pain experience in an elderly care context
Authors: Hellström Muhli Ulla
Published: October 2010

The main concern was to show how a discourse and communication based approach in the context of the care of elderly, provides a basis for reflecting on pain. Based on six hours of recorded, transcribed and translated data from talk encounters between care professionals /elderly clients, an activity analysis of institutional settings and categorization of interactional discourse was made. There was a twofold focus: how elderly people initiate painful accounts, and how the professionals orient to such accounts. The pain-talks are governed by the institutional practice of phases: framing mapping troubles and symptoms, clients self presentations, counseling, and concluding. This structure shows the dialogical accounts as a communicative activity (type) of pain talk. A thematic interactional map of critical moments related to pain as 1) social death and hope, 2) and presentation of self as past and self as present, was achieved. The elderly talk about pain as an identity construction. Pain is a link between past, present and future identity. It is suggested that the caring aspect of professional skills is to support hope and to change the focus from social death to life and recovering.
Constructing and negotiating ‘change’ in follow-up meetings for intimately violent men
Authors: Partanen Terhi , Wahlström Jarl , Holma Juha
Published: October 2010

This study reports on follow-up meetings of a group treatment program for intimately violent men. The focus is on the construction of change narratives; on how indicators of ‘successful change’ are negotiated and produced in the conversations. We describe in detail five discursive strategies used by client and therapist participants, e.g., the construction of temporal differences, personalizing the problem, reformulations of failure stories, taking presence at the follow-up as evidence of success, and the use of outsiders as an audience. We also demonstrate how the notion of success is ascertained and to whom credit is given for achieving it. We conclude that the followup meetings are established as an integrated part of the whole treatment program, and contribute to the promotion of the treatment ideology.
Disconnects between news framing and parental discourse concerning the state-mandated HPV vaccine: Implications for dialogic health communication and health literacy
Authors: St. John Burton , Pitts Margaret , Adams Tufts Kimberly
Published: October 2010

In 2007, Virginia became the first state to mandate the human papillomavirus (HPV) vaccine, requiring that parents of girls entering 6th grade in 2009 decide to either vaccinate their daughters or sign the ‘opt-out’ waiver. This investigation is the first to explore how both the news media and parents framed and responded to the newly-mandated HPV vaccine. This research reveals disjoints between newspaper reports and information needed by families, leaving parents feeling skeptical about, frustrated with, and intolerant of the state directive. This study discusses the implications of these gaps for parental healthcare decision-making and provides suggestions for constructing a more dialogic, community-based approach that can increase health literacy regarding the HPV vaccine.
Living with pain: Narrating an ideological position toward healthcare
Authors: Vickers Caroline H. , Zychowicz Suzanne , Morones Jose R.
Published: October 2010

The purpose of this study is to demonstrate how individual experiences shape ideologies toward healthcare. To demonstrate, we analyze conversational narrative data about health and healthcare between a dominant Spanish-speaking Mexican immigrant woman, Maria, and the researcher, Caroline. Findings demonstrate that Maria's narrative about her experience receiving healthcare for a knee injury reveals her ideological stance toward healthcare in both the United States and Mexico. In particular, the narrative reflects an ideological position in which medical providers neglect patients and strip them of agency in making choices about their own healthcare. Cultural competence, then, is not only about gaining knowledge of patients’ cultural groups but also about understanding how patients’ life experiences shape them as autonomous individuals with socially constructed attitudes toward healthcare.
Preceptor Preparation: An Investment in the Future Generation of Nurses
Authors: Luhanga Florence Loyce , Dickieson Patti , Mossey Sharolyn D.
Published: October 2010

Nurse preceptors fulfill a primary role in the success of preceptorship experiences during the education of student nurses in their final year of study. Evidence suggests that this success depends greatly on adequate preceptor role preparation and support. The purposes of this qualitative, descriptive study were to explore and describe preceptor role support and development within the context of a rural and northern mid-sized Canadian community. More specifically, in this study the following are described: preceptors (a) perception of past role preparation and current role support; (b) use and evaluation of the existing print-based fourth-year Preceptor Resource Manual (PRM); (c) perception of role support facilitators and barriers; and (d) recommendations for improvements to preceptor role preparation and support. Data were collected through individual and group interviews. Through content analysis four major themes emerged: accessible resources, role complexity, partners in precepting, and role development.
Protective Effects of Phyllanthus acidus (L.) Skeels Extract on Acetaminophen Mediated Hepatic Injury and Oxidative Stress in Wistar Rats
Authors: Jain Nilesh K , Lodhi Santram , Jain Avijeet , Nahata Alok , Singhai Abhay K
Published: October 2010

Phyllanthus acidus (L.) Skeels fruit is used as a liver tonic in Indian traditional medicine. The present study was undertaken to investigate the protective effects of ethanolic extract (70%) of Phyllanthus acidus fruits (PAE) on acetaminophen (paracetamol, APAP) induced acute hepatotoxicity in Wistar rats. The effect on cytochrome P450 enzyme system using pentobarbital induced sleeping time (PST) and free radical scavenging potential using 2,2-diphenyl-1-picrylhydrazil (DPPH) was also determined. Hepatotoxicity was achieved by administering a single oral dose of APAP (2 g/kg). PAE administered at a dose of 125, 250 and 500 mg/kg, p.o. showed a significant hepatoprotection against APAP-liver toxicity as evidenced by reduced serum markers and histopathological observation of liver tissues. Reduced enzymatic and nonenzymatic antioxidant levels and elevated lipid peroxidation due to APAP intoxication, were significantly restored to normalcy by pretreatment with PAE. The PAE also showed prolongation of PST and DPPH scavenging potential. The results were compared with silymarin (100 mg/kg, p.o.), which found more effective than plant extract being tested. Collectively, the preset study clear that the ethanolic extract of Phyllanthus acidus fruit has hepatoprotective activity against APAP-induced hepatotoxicity in rats and this is likely mediated through the inhibition of P450-mediated APAP bioactivation, free radical scavenging and antioxidant activities.
Peroxisome-Generated Hydrogen Peroxide as Important Mediator of Lipotoxicity in Insulin-Producing Cells
Authors: Elsner Matthias , Gehrmann Wiebke , Lenzen Sigurd
Published: October 2010

OBJECTIVE

Type 2 diabetes is a complex disease that is accompanied by elevated levels of nonesterified fatty acids (NEFAs), which contribute to β-cell dysfunction and β-cell loss, referred to as lipotoxicity. Experimental evidence suggests that oxidative stress is involved in lipotoxicity. In this study, we analyzed the molecular mechanisms of reactive oxygen species-mediated lipotoxicity in insulin-producing RINm5F cells and INS-1E cells as well as in primary rat islet cells.

RESEARCH DESIGN AND METHODS

The toxicity of saturated NEFAs with different chain lengths upon insulin-producing cells was determined by MTT and propidium iodide (PI) viability assays. Catalase or superoxide dismutase overexpressing cells were used to analyze the nature and the cellular compartment of reactive oxygen species formation. With the new H2O2-sensitive fluorescent protein HyPer H2O2 formation induced by exposure to palmitic acid was determined.

RESULTS

Only long-chain (>C14) saturated NEFAs were toxic to insulin-producing cells. Overexpression of catalase in the peroxisomes and in the cytosol, but not in the mitochondria, significantly reduced H2O2 formation and protected the cells against palmitic acid-induced toxicity. With the HyPer protein, H2O2 generation was directly detectable in the peroxisomes of RINm5F and INS-1E insulin-producing cells as well as in primary rat islet cells.

CONCLUSIONS

The results demonstrate that H2O2 formation in the peroxisomes rather than in the mitochondria are responsible for NEFA-induced toxicity. Therefore, we propose a new concept of fatty acid-induced β-cell lipotoxicity mediated via reactive oxygen species formation through peroxisomal β- oxidation.
P-Selectin Glycoprotein Ligand-1 Deficiency Is Protective Against Obesity-Related Insulin Resistance
Authors: Sato Chikage , Shikata Kenichi , Hirota Daisho , Sasaki Motofumi , Nishishita Shingo , Miyamoto Satoshi , Kodera Ryo , Ogawa Daisuke , Tone Atsuhito , Kataoka Hitomi Usui , Wada Jun , Kajitani Nobuo , Makino Hirofumi
Published: October 2010

OBJECTIVE

An inflammatory process is involved in the mechanism of obesity-related insulin resistance. Recent studies indicate that monocyte chemoattractant protein-1 (MCP-1) is a major chemokine that promotes monocyte infiltration into adipose tissues; however, the adhesion pathway in adipose tissues remains unclear. We aimed to clarify the adhesion molecules that mediate monocyte infiltration into adipose tissue.

RESEARCH DESIGN AND METHODS

We used a DNA microarray to compare the gene expression profiles in epididymal white adipose tissues (eWAT) between db/db mice and C57/BL6 mice each fed a high-fat diet (HFD) or a low-fat diet (LFD). We investigated the change of insulin resistance and inflammation in eWAT in P-selectin glycoprotein ligand-1 (PSGL-1) homozygous knockout (PSGL-1−/−) mice compared with wild-type (WT) mice fed HFD.

RESULTS

DNA microarray analysis revealed that PSGL-1, a major ligand for selectins, is upregulated in eWAT from both db/db mice and WT mice fed HFD. Quantitative real-time RT-PCR and immunohistochemistry showed that PSGL-1 is expressed on both endothelial cells and macrophages in eWAT of obese mice. PSGL-1−/− mice fed HFD showed a remarkable reduction of macrophage accumulation and expression of proinflammatory genes, including MCP-1 in eWAT. Moreover, adipocyte hypertrophy, insulin resistance, lipid metabolism, and hepatic fatty change were improved in PSGL-1−/− mice compared with WT mice fed HFD.

CONCLUSIONS

These results indicate that PSGL-1 is a crucial adhesion molecule for the recruitment of monocytes into adipose tissues in obese mice, making it a candidate for a novel therapeutic target for the prevention of obesity-related insulin resistance.
Production of Functional Glucagon-Secreting α-Cells From Human Embryonic Stem Cells
Authors: Rezania Alireza , Riedel Michael J. , Wideman Rhonda D. , Karanu Francis , Ao Ziliang , Warnock Garth L. , Kieffer Timothy J.
Published: October 2010

OBJECTIVE

Differentiation of human embryonic stem (hES) cells to fully developed cell types holds great therapeutic promise. Despite significant progress, the conversion of hES cells to stable, fully differentiated endocrine cells that exhibit physiologically regulated hormone secretion has not yet been achieved. Here we describe an efficient differentiation protocol for the in vitro conversion of hES cells to functional glucagon-producing α- cells.

RESEARCH DESIGN AND METHODS

Using a combination of small molecule screening and empirical testing, we developed a six-stage differentiation protocol for creating functional α-cells. An extensive in vitro and in vivo characterization of the differentiated cells was performed.

RESULTS

A high rate of synaptophysin expression (>75%) and robust expression of glucagon and the α-cell transcription factor ARX was achieved. After a transient polyhormonal state in which cells coexpress glucagon and insulin, maturation in vitro or in vivo resulted in depletion of insulin and other β-cell markers with concomitant enrichment of α-cell markers. After transplantation, these cells secreted fully processed, biologically active glucagon in response to physiologic stimuli including prolonged fasting and amino acid challenge. Moreover, glucagon release from transplanted cells was sufficient to reduce demand for pancreatic glucagon, resulting in a significant decrease in pancreatic α-cell mass.

CONCLUSIONS

These results indicate that fully differentiated pancreatic endocrine cells can be created via stepwise differentiation of hES cells. These cells may serve as a useful screening tool for the identification of compounds that modulate glucagon secretion as well as those that promote the transdifferentiation of α-cells to β-cells.
Plane trivalent trees and their patterns
Authors: Delorme Charles
Published: October 2010

The aim of this paper is to characterize the patterns of successive distances of leaves in plane trivalent trees, and give a very short characterization of their parity pattern. Besides, we count how many trees satisfy some given sequences of patterns.
The effect of soil surfactants on soil hydrological behavior, the plant growth environment, irrigation efficiency and water conservation
Authors: Moore Demie , Kostka Stanley , Boerth Thomas , Franklin Mica , Ritsema Coen , Dekker Louis , Oostindie Klaas , Stoof Cathelijne , Wesseling Jan
Published: October 2010

The effect of soil surfactants on soil hydrological behavior, the plant growth environment, irrigation efficiency and water conservation

Soil water repellency causes at least temporal changes in the hydrological properties of a soil which result in, among other things, suboptimal growing conditions and increased irrigation requirements. Water repellency in soil is more widespread than previously thought and has been identified in many soil types under a wide array of climatic conditions worldwide. Consequences of soil water repellency include loss of wettability, increased runoff and preferential flow, reduced access to water for plants, reduced irrigation efficiency, increased requirement for water and other inputs, and increased potential for non-point source pollution. Research indicates that certain soil surfactants can be used to manage soil water repellency by modifying the flow dynamics of water and restoring soil wettability. This results in improved hydrological behavior of those soils. Consequently, the plant growth environment is also improved and significant water conservation is possible through more efficient functioning of the soil.
Improvement performance of Al-Wathba settling tank by a computational fluid dynamics model
Authors: Kriš Jozef , Hadi Ghawi
Published: October 2010

Improvement performance of Al-Wathba settling tank by a computational fluid dynamics model

An investigation has been carried out using the FLUENT Computational Fluid Dynamics (CFD) software, which uses the finite-volume method to determine whether it is feasible to improve the capacity and quality of the clarifier at the Al-Wathba Water Treatment Works (Iraq) by some relatively inexpensive means. Simulations were carried out with two dimensional, radially symmetric models, representing the existing configuration as well as a number of proposed modifications involving baffles and additional clarified water off-takes. A convection-diffusion equation, which is extended to incorporate the sedimentation of sludge flocs in the field of gravity, governs the mass transfer in the clarifier. The standardk-ε turbulence model is used to compute the turbulent motion, and our CFD model accounts for buoyancy flow. The sludge settling velocity was measured as a function of the concentration, and we have used the double-exponential settling velocity function to describe its dependence on the concentration. The CFD model is validated using measured concentration profiles. The results were evaluated on the basis of the simulated profiles of vertical up-flow velocity in the body of the clarifier.
Editorial
Authors: Mach Mojmír
Published: October 2010

Editorial

Communication - Dialogue - Co-operation - Solving problems. These are the words of nowadays Europe. Such approaches should be used in broad spectrum of life as well as in toxicology. It is therefore admirable that EUROTOX commissars, mainly past-president Prof. Liesivuori, invited all heads of European toxicological societies to discuss current issues of toxicology in Europe during IUTOX meeting held in Barcelona in July 2010. Renowned scientists and regulatory officers from Government, Industry and Academia made appearance and talked about contribution of toxicological research to society, importance of communication and education. The strategic meeting was successful. Prof. Liesivuori expressed gratitude to all delegates for the great suggestions and key findings resulting from the brainstorming sessions conducted during the meeting. Majority of delegates agreed that education in toxicology and related fields is the top priority for future. Communication towards society, in the sense of explaining possible risks, should be an important concern as well. Taking a good example from EUROTOX, on the verge of summer the Slovak Toxicology Society SETOX organizes meeting of the toxicological societies from the Central Europe, i.e. Slovak, Czech, Polish, Austrian and Hungarian societies of toxicology. First positive step was done by Visegrad Fund and Federation of European Toxicologists & European Societies of Toxicology, which supported this meeting. It is essential for successful co-operation to establish strong connections, which can be further crucial for meaningful and highly profitable information to society.
Importance of molecular cell biology investigations in human medicine in the story of the Hutchinson-Gilford progeria syndrome
Authors: Raška Ivan
Published: October 2010

Importance of molecular cell biology investigations in human medicine in the story of the Hutchinson-Gilford progeria syndrome

Ranged among laminopathies, Hutchinson-Gilford progeria syndrome is a syndrome that involves premature aging, leading usually to death at the age between 10 to 14 years predominatly due to a myocardial infarction or a stroke. In the lecture I shall overview the importance of molecular cell biology investigations that led to the discovery of the basic mechanism standing behind this rare syndrome. The genetic basis in most cases is a mutation at the nucleotide position 1824 of the lamin A gene. At this position, cytosine is substituted for thymine so that a cryptic splice site within the precursor mRNA for lamin A is generated. This results in a production of abnormal lamin A, termed progerin, its presence in cells having a deleterious dominant effect. Depending on the cell type and tissue, progerin induces a pleiotropy of defects that vary in different tissues. The present endeavour how to challenge this terrible disease will be also mentioned.
Chemiluminescence response induced by mesenteric ischaemia/reperfusion: effect of antioxidative compounds ex vivo
Authors: Nosáľová Viera , Sotníková Ružena , Drábiková Katarína , Fialová Silvia , Košťálová Daniela , Banášová Silvia , Navarová Jana
Published: October 2010

Chemiluminescence response induced by mesenteric ischaemia/reperfusion: effect of antioxidative compoundsex vivo

Ischaemia and reperfusion (I/R) play an important role in human pathophysiology as they occur in many clinical conditions and are associated with high morbidity and mortality. Interruption of blood supply rapidly damages metabolically active tissues. Restoration of blood flow after a period of ischaemia may further worsen cell injury due to an increased formation of free radicals. The aim of our work was to assess macroscopically the extent of intestinal pathological changes caused by mesenteric I/R, and to study free radical production by luminol enhanced chemiluminescence (CL) of ileal samples. In further experiments, the antioxidative activity of the drugs tested was evaluated spectrophotometrically by the use of the DPPH radical. We studied the potential protectiveex vivoeffect of the plant origin compound arbutin as well as of the pyridoindole stobadine and its derivative SMe1EC2. I/R induced pronounced haemorrhagic intestinal injury accompanied by increase of myeloperoxidase (MPO) and N-acetyl-β-D-glucosaminidase (NAGA) activity. Compared to sham operated (control) rats, there was only a slight increase of CL response after I/R, probably in association with neutrophil increase, indicated by enhanced MPO activity. All compounds significantly reduced the peak values of CL responses of the ileal samplesex vivo, thus reducing the I/R induced increase of free radical production. The antioxidants studied showed a similar inhibitory effect on the CL response influenced by mesenteric I/R. If provedin vivo, these compounds would represent potentially useful therapeutic antioxidants.
Source and depositional processes of coarse-grained limestone event beds in Frasnian slope deposits (Kostomłoty-Mogiłki quarry, Holy Cross Mountains, Poland)
Authors: Vierek Aleksandra
Published: October 2010

Source and depositional processes of coarse-grained limestone event beds in Frasnian slope deposits (Kostomłoty-Mogiłki quarry, Holy Cross Mountains, Poland)

The Kostomłoty-Mogiłki succession is situated in the Kostomłoty transitional zone between the shallow-water Kielce stromatoporoid-coral platform and the deeper Łysogóry basin. In the Kostomłoty-Mogiłki quarry, the upper part of the Szydłówek Beds and Kostomłoty Beds are exposed. The Middle-Upper Frasnian Kostomłoty Beds are composed of shales, micritic and nodular limestones with abundant intercalations of detrital limestones. The dark shales and the micritic and nodular limestones record background sedimentation. The interbedded laminated and detrital limestones reflect high-energy deposition (= event beds). These event beds comprise laminated calcisiltites, fine-grained calcarenites, coarse-grained grain-supported calcirudites fabrics, and matrix-supported calcirudites. The material of these event beds was supplied by both erosion of the carbonate-platform margin and cannibalistic erosion of penecontemporaneous detrital limestones building the slope of this platform. Storms and the tectonic activity were likely the main causes of erosion. Combined and gravity flows were the transporting mechanisms involved in the reworking and redeposition.
A Rare Case of Severe Intoxication from Multiple Bee Stings with a Favorable Outcome
Authors: Iliev Yanko , Tufkova Stoilka , Prancheva Maria
Published: October 2010

A Rare Case of Severe Intoxication from Multiple Bee Stings with a Favorable Outcome

A 73-year old female of no allergic diathesis was attacked by bees and stung all over her body accidentally sustaining more than 518 stings for a very short time. Severe acute poisoning developed from the bee venom, manifested by coma, rhabdomyolysis, toxic hepatitis, acute renal failure, gastric hemorrhage and anemia. Following an active treatment the patient recovered. Literature search shows this to be a rare case of survival after multiple bee stings.
IRT–ZIP Modeling for Multivariate Zero-Inflated Count Data
Authors: Wang Lijuan
Published: October 2010

This study introduces an item response theory–zero-inflated Poisson (IRT–ZIP) model to investigate psychometric properties of multiple items and predict individuals' latent trait scores for multivariate zero-inflated count data. In the model, two link functions are used to capture two processes of the zero-inflated count data. Item parameters are included to investigate item performance from both propensity and level perspectives. The application of the model was illustrated by analyzing the substance use data from the National Longitudinal Study of Youth. A simulation study based on the empirical data analysis scenario showed that the item parameters can be recovered accurately and precisely with adequate sample sizes. Limitations and future directions are discussed.
Psychometric Properties of Activity, Self-Efficacy, and Quality-of-Life Measures in Individuals with Parkinson Disease
Authors: Dal Bello-Haas Vanina , Klassen Laura , Sheppard M. Suzanne , Metcalfe Amy
Published: October 2010

Purpose: To examine the psychometric properties of six outcome measures in people with Parkinson disease (PD).

Method: Twenty-four participants completed the following twice within 2 weeks: the timed up-and-go test (TUG), Northwestern University Disability Scale (NUDS), Schwab & England ADL Scale (S&E), Activities-specific Balance Confidence (ABC) Scale, PD Questionnaire—Short Form (PDQ 8), and Stanford Self-Efficacy for Managing Chronic Disease 6-Item Scale (SSE). Internal consistency, test–retest reliability (ICC[3,1]), and minimal detectable change (MDC) scores were calculated. Convergent and discriminant validity of the ABC were examined.

Results: Cronbach's alpha scores for the NUDS, ABC, PDQ-8, and SSE were 0.47, 0.92, 0.72, and 0.91 respectively. The intra-class correlation coefficient (ICC[3,1]) for the TUG was 0.69 and could be improved by averaging two trials. ICCs for the NUDS, S&E, ABC, PDQ-8, and SSE were 0.56, 0.70, 0.79, 0.82, and 0.72 respectively. The ABC correlated with the TUG (r=−0.44, p=0.03) and with PDQ-8 (rs=0.51, p=0.01) and NUDS (rs=0.48, p=0.02) walking items. The ABC was able to discriminate between stages 1 and 3 of disease progression but not between stages 1 and 2, which suggests that the ABC can distinguish large differences in disease progression but cannot detect more subtle differences.

Conclusions: Homogeneity of the ABC, PDQ-8, and SSE is good to excellent. Test–retest reliability scores of all measures except the NUDS are moderate to good. The ABC is a valid measure for use in PD. The MDC statistic may be useful for interpreting group score changes.
Contextualizing School Textbook Revision
Authors: Fuchs Eckhardt
Published: October 2010

The words “textbook revision” immediately conjure up certain images. We generally think of conflicts surrounding the contents of textbooks, conflicts which are debated in public and usually have an international dimension. Textbook revision generally refers to books on history, geography and social studies, occasionally also religion or biology. It generally relates to those activities aimed at correcting false or distorted interpretations in school textbooks. In addition, it involves two further aspects: improving the quality of teaching with revised textbooks, and conveying universal norms in addition to knowledge of the subject. History and social studies teaching can thus make an important contribution to peace and human rights education.
Textbook Revision and Beyond
Authors: Banerjee Basabi Khan , Stöber Georg
Published: October 2010

Whereas “classical” textbook revision involved two or more nation-states, this article explores current challenges in this field which are internal or go beyond the level of nation-states: textbook activities after internal wars, the search for a “European textbook,” immigration, international schools, and examinations. All of these challenges touch upon the question of identities which are distinct from “traditional” national identities. The article sketches the respective backgrounds of these current challenges as well as practical aspects that need to be considered. We also question whether solutions can be found by replacing constricted identities with more comprehensive ones.
Textbook Conflicts in South Asia
Authors: Nair Deepa
Published: October 2010

The aftermath of World War II saw the emergence of many new nation-states on the Asian geopolitical map and a simultaneous attempt by these states to claim the agency of nationhood and to create an aura of a homogenous national identity. Textbooks have been the most potent tools used by nations to inject an idea of a national memory - in many instances with utter disregard for fundamental contradictions within the socio-political milieu. In South Asia, political sensitivity towards transmission of the past is reflected in the attempts of these states to revise or rewrite versions which are most consonant with the ideology of dominant players (political parties, religious organizations, ministries of education, publishing houses, NGOs, etc.) concerning the nature of the state and the identity of its citizens. This paper highlights the fundamental fault lines in the project of nation-building in states in South Asia by locating instances of the revision or rewriting of dominant interpretations of the past. By providing an overview of various revisionist exercises in South Asia, an attempt will be made to highlight important issues that are fundamental to the construction of identities in this diverse continent.
Univocality within Multivocality
Authors: Podeh Elie
Published: October 2010

Previous research on the way in which the Arab-Israeli conflict and the image of the Arab have been presented in Jewish history and civics textbooks established that there have been three phases, each typified by its own distinctive textbooks. The shift from the first to the third generation of textbooks saw a gradual improvement in the way the Other has been described, with the elimination of many biases, distortions and omissions. This article explores whether new history textbooks, published from 2000 to 2010, have entrenched or reversed this trend. With the escalation of the Israeli-Palestinian conflict since the early 2000s, one might have expected that the past linear process of improvement would be reversed. However, textbooks written over the last decade do not substantially differ from those written in the 1990s, during the heyday of the peace process. The overall picture is, therefore, that the current textbooks do not constitute a fourth generation.
Nationalism, Peace Education, and History Textbook Revision in Scandinavia, 1886-1940
Authors: Elmersjö Henrik Åström , Lindmark Daniel
Published: October 2010

History as a school subject has been a thorny issue for advocates of peace education at least since the 1880s. Efforts, including the substitution of cultural history for military history, have been made to ensure that history teaching promotes international understanding, not propagates chauvinism. The Norden Associations of Scandinavia, which were involved in textbook revision since 1919, achieved some success by altering contents, but national myths remained central to each country's historical narrative, making it difficult to give history education its desired international orientation.