bluuebunny/crossref_metadata_2025 huggingface dataset:
Community and household determinants of water quality in coastal Ghana
Authors: McGarvey Stephen T. , Buszin Justin , Reed Holly , Smith David C. , Rahman Zarah , Andrzejewski Catherine , Awusabo-Asare Kofi , White Michael J.
Published: March 2008

Associations between water sources, socio-demographic characteristics and household drinking water quality are described in a representative sample of six coastal districts of Ghana's Central Region. Thirty-six enumeration areas (EAs) were randomly chosen from a representative survey of 90 EAs in rural, semi-urban and urban residence strata. In each EA, 24 households were randomly chosen for water quality sampling and socio-demographic interview. Escherichia coli per 100 ml H2O was quantified using the IDEXX Colilert® system and multi-stage regression models estimated cross-sectional associations between water sources, sanitation and socio-demographic factors. Almost three quarters, 74%, of the households have >2 E. coli /100 ml H2O. Tap water has significantly lower E. coli levels compared with surface or rainwater and well water had the highest levels. Households with a water closet toilet have significantly lower E. coli compared with those using pit latrines or no toilets. Household size is positively associated, and a possessions index is negatively associated, with E. coli. Variations in community and household socio-demographic and behavioural factors are key determinants of drinking water quality. These factors should be included in planning health education associated with investments in water systems.
A methodological framework supporting trans-boundary water agreements: the case of the Nestos/Mesta river basin
Authors: Eleftheriadou Eleni , Mylopoulos Yannis
Published: March 2008

Management of trans-boundary river basins is a major issue that has attracted great attention in recent years. The European Water Framework Directive (WFD) recommends management at a river basin level, overlooking any national or administrative borders. This new managerial approach impels water managers to disregard the trans-boundary nature of the water resources while considering an integrated river basin where only geographical boundaries exist.

The new challenge for scientists and water managers is the establishment of water agreements between countries sharing water resources. These agreements should aim at the settlement of tensions and conflicts while providing the essential framework for cooperation and consensus building. Apparently, the content of these agreements should comply with international law and the relevant international conventions especially, as noted by the WFD, the UNECE Convention on the Protection and Use of Trans-boundary Watercourses and International Lakes (known as the Helsinki Rules), approved by the European Council in 1995.

This paper examines the efficiency of water agreements and their precedent negotiations using the best known international examples while focusing on the Greek–Bulgarian agreement for the waters of the Nestos/Mesta River and its compliance with the WFD and the Helsinki Rules. As shown, the two countries have failed to implement a joint effort to put it into action; hence a methodological framework is proposed including certain strategic steps that can guide the two countries to a more effective and applicable water agreement taking into account the peculiarities of this trans-boundary area.
Soft systems methodology for performance measurement in the Uganda water sector
Authors: Kayaga Sam
Published: March 2008

Water and sanitation services in developing countries are delivered in an extremely complex institutional environment, characterised by “soft” problems, that is problems with significant political and social components whose “what” and “how” cannot be defined early in the intervention process. A problem situation common in developing countries depicting “soft” characteristics is how to improve the effectiveness and efficacy of existing performance measurement systems to track the progress towards achievement of water/sanitation-related Millennium Development Goals (MDGs). Such problem situations are better handled using soft systems methodology (SSM), a methodology recommended by Professor Checkland and his research colleagues at Lancaster University, UK. In 2003, SSM was applied in an intervention that aimed to improve performance measurement systems in the Uganda water/sanitation sector. Through strong participation of the key stakeholders, a team of researchers with their local counterparts in Uganda developed and field tested a performance measurement framework. According to an evaluation by the international donor community, policy makers and managers in the sector, the past three annual water/sanitation sector performance reports compiled using the performance measurement framework have depicted a progressive qualitative improvement.
Mountain Pine Beetle Presence Affects Nest Patch Choice of Red‐Breasted Nuthatches
Authors: NORRIS ANDREA R. , MARTIN KATHY
Published: March 2008

Abstract: The mountain pine beetle (Dendroctonus ponderosae) outbreak in western Canada poses significant conservation concern; thus, insights into its effects on wildlife habitat are essential. We used generalized linear mixed models to examine the influence of quaking aspen (Populus tremuloides) and mountain pine beetle—infected lodgepole pine (Pinus contortus) on nest patch selection of red‐breasted nuthatches (Sitta canadensis) in central British Columbia, Canada. Prior to the outbreak, nuthatches selected nest patches with 64% more suitable nest trees (standing dead aspen, ≥12.5 cm dbh) than available (103 trees/ha vs. 63 trees/ha, respectively), but in outbreak years nuthatches chose nest patches with 37% more beetle‐infected pine trees than available (63 trees/ha vs. 46 trees/ha, respectively). Our results suggest that nuthatches select sites that maximize nesting and foraging opportunities and, during food pulses, may trade off higher densities of suitable nest trees for higher densities of foraging trees. (JOURNAL OF WILDLIFE MANAGEMENT 72(3):733–737; 2008)
Use of Occupancy Models to Estimate the Influence of Previous Live Captures on DNA‐Based Detection Probabilities of Grizzly Bears
Authors: BOULANGER JOHN , WHITE GARY C. , PROCTOR MICHAEL , STENHOUSE GORDON , MACHUTCHON GRANT , HIMMER STEFAN
Published: March 2008

Abstract: Large carnivores potentially change their behavior following physical capture, becoming less responsive to the attractants that resulted in their capture, which can bias population estimates where the change in behavior is not appropriately modeled. We applied occupancy models to efficiently estimate and compare detection probabilities of previously collared grizzly bears (Ursus arctos) with bears captured at DNA hair‐snag sites that were not previously collared. We found that previously captured bears had lower detection probabilities, although their detection probabilities were still >0, implying that they were still visible to be sampled via the DNA hair‐snag grid, which was able to detect finer differences in capture probabilities of previously collared bears compared with Huggins closed‐captures population models. To obtain relatively unbiased population estimates for DNA surveys, heterogeneity caused by previous live capture should be accounted for in the population estimator. (JOURNAL OF WILDLIFE MANAGEMENT 72(3):589–595; 2008)
Effects of Relocation on Movements and Home Ranges of Eastern Box Turtles
Authors: HESTER JOY M. , PRICE STEVEN J. , DORCAS MICHAEL E.
Published: March 2008

Abstract: To examine effects of relocation on eastern box turtles (Terrapene carolina), we compared home ranges and movement patterns of 10 resident and 10 relocated box turtles in Davidson, North Carolina, USA. Home ranges of relocated turtles were approximately 3 times larger than those of resident turtles when measured by minimum convex polygons, 6 times larger than resident turtles when measured with 95% kernels and 7.5 times larger than resident turtles when measured by 50% kernels. Relocated turtles also moved a greater average distance per day than resident turtles. Additionally, 5 relocated turtles experienced mortality or disappearance compared to no mortality or disappearance of resident turtles. Our results raise questions about the success of relocation as a management strategy for eastern box turtles. (JOURNAL OF WILDLIFE MANAGEMENT 72(3):772–777; 2008)
Characterization and degradation of pectin derived from Budimka apple
Authors: Nikolic Milos , Mojovic Ljiljana
Published: March 2008

The characterization of apple pectin and its oligogalacturonic fractions derived from the autochthones apple variety Budimka, characteristic for central Serbia, is described in this paper. After extraction, the apple pectin was subjected to controlled enzymatic hydrolysis by polygalacturonase (PG) and pectin lyase (PL) from Aspergillus niger and then fractionated by ion-exchange column chromatography on Dowex 1X-8 (200-400 mesh). Saturated oligo?galacturonic acids, obtained by controlled hydrolysis with PG, were efficiently separated by elution with a gradient of Na acetate buffer (pH 6.0), while unsaturated oligogalacturonic acids, obtained by controlled hydrolysis with PL, were separated on the same resin, using a gradient of Na formate buffer (pH 4.7) as the eluent. The yields of the fractions with the particular degree of polymerization (DP) were also determined. The total content of neutral saccharides in the original Budimka apple pectin was detected by HPLC analysis of the 4-nitrobenzoyl derivatives of the sugar, and amounted to 5.31%. Among the neutral saccharides, contents of galactose, glucose, rhamnose, arabinose, xylose and mannose were detected.
Expanded and combined uncertainty in measurements by GM counters
Authors: Stankovic Koviljka , Arandjic Danijela , Lazarevic Djordje , Osmokrovic Predrag
Published: March 2008

This paper deals with possible ways of obtaining expanded and combined uncertainty in measurements for four types of GM counters with a same counter?s tube, in cases when the contributors of these uncertainties are cosmic background radiation and induced overvoltage phenomena. Nowadays, as a consequence of electromagnetic radiation, the latter phenomenon is especially marked in urban environments. Based on experimental results obtained, it has been established that the uncertainties of an influenced random variable ?number of pulses from background radiation? and ?number of pulses induced by overvoltage? depend on the technological solution of the counter?s reading system and contribute in different ways to the expanded and combined uncertainty in measurements of the applied types of GM counters.
Contact interactions, stress and material symmetry
Authors: Podio-Guidugli P.
Published: March 2008

An argument is given intimating that, for nonsimple materials, the concepts of contact interaction and material symmetry, as well as the bridging concept of stress, should be carefully revised and generalized. .
Structural optimization considering the probabilistic system response
Authors: Papadrakakis M. , Lagaros N.D. , Plevris V.
Published: March 2008

In engineering problems, the randomness and uncertainties are inherent and the scatter of structural parameters from their nominal ideal values is unavoidable. In Reliability Based Design Optimization (RBDO) and Robust Design Optimization (RDO) the uncertainties play a dominant role in the formulation of the structural optimization problem. In an RBDO problem additional non deterministic constraint functions are considered while an RDO formulation leads to designs with a state of robustness, so that their performance is the least sensitive to the variability of the uncertain variables. In the first part of this study a metamodel assisted RBDO methodology is examined for large scale structural systems. In the second part an RDO structural problem is considered. The task of robust design optimization of structures is formulated as a multi-criteria optimization problem, in which the design variables of the optimization problem, together with other design parameters such as the modulus of elasticity and the yield stress are considered as random variables with a mean value equal to their nominal value. .
Hall effect on MHD mixed convection flow of a viscoelastic fluid past an infinite vertical porous plate with mass transfer and radiation
Authors: Chaudhary R.C. , Jain Preeti
Published: March 2008

An unsteady hydro-magnetic flow of a viscoelastic fluid from a radiative vertical porous plate has been studied with mass transfer, taking the effect of Hall currents into account. The resulting problem has been solved analytically and the closed form solutions are obtained for velocity, temperature and concentration distributions as well as for the shearing stress, rate of heat and mass transfer at the wall. The influence of the various parameters like Hall parameter, magnetic parameter, viscoelastic parameter, frequency parameter etc. on the flow field is examined with the help of figures and tables.
Popularising the ‘New International Political Economy’: The ATTAC Movement
Authors: Bobulescu Roxana
Published: March 2008

Born in France in 1997, the ATTAC (Association for the Taxation of Financial Transactions to Aid Citizens) movement is popularising IPE (international political economy), the interdisciplinary field of study born in the United Kingdom in the 1970s. The affinity between the ideas and main concerns of ATTAC and IPE can be clearly stated. ATTAC is a popular education movement, promoting a critical reading of globalisation. It uses critical pedagogy and is largely supported by ‘resisting intellectuals’, who are the newborn ‘organic intellectuals’ once envisioned by Antonio Gramsci.
Language Skills and Economic Returns
Authors: Garrouste Christelle
Published: March 2008

This article focuses on the contributions from the emerging positivist epistemological approach, endorsed by the economics of language and the economics of education, to study the returns to language skills, assuming that language competencies constitute key components of human capital. It presents initial results from a study on economic returns to language skills in eight countries enrolled in the International Adult Literacy Survey (IALS) – Chile, the Czech Republic, Denmark, Finland, Hungary, Italy, Norway and Italian-speaking Switzerland. The study shows commonalities between countries in terms of language skills valuing, beyond the type of language policy applied at the national level. In each of the eight countries compared, skills in a second language are estimated to be a major factor constraining affecting wage opportunities.
Education and Civic Engagement among Norwegian Youth
Authors: Lauglo Jon , Øia Tormod
Published: March 2008

What role does formal education play in the political socialization of youth? The article presents findings from a national survey in 2002 of more than 11,000 youths aged 13–19 in Norway. Indicators of political socialization are: an index of expressed interest in politics and social issues, participation in membership organizations of a political kind, political activism, and unlawful forms of political protest. Except for unlawful forms of protest, interest in politics and social issues, and actual participation, increase with educational achievement and especially with ambition for higher education. But all forms of political participation (but not mere interest in politics) increase with greater than average conflict with teachers and school authority. These findings persist after controls for social class, parental education, and political socialization in the family.
Educational Technology in Crisis
Authors: Fainholc Beatriz
Published: March 2008

The presentation of the historical epistemological path is needed to understand and reconsider the discipline of Educational Technology in articulation to contributions of rupturistic theorists in order to reach to a critical proposal and a revision of its field. This field is facing a deep crisis within a time of world crisis, specially in the southern hemisphere and in contexts of migration of nomad or poor users. The technology should be ‘appropriate’, socially grounded and culturally adequate in its pedagogical mediations depending on diverse scenarios and actors, who will select and combine traditional elements with virtual ones to be delivered in an electronic formats. Appropriate and Critical Technology is a special technological discipline and a knowledge field where we cultivate open and reflexive special knowledge, towards research and contrast at socio-educational practices, mediated by pedagogical projects and materials articulated with ICT. Its study objects are the educational-technological mediations as historical - cultural - semiologic and didactic environments and tools in diverse formats, which provoke different domains of the socio - cognitive structuring of learners in a situated and distributed way, inscribed within formal and non- formal, face-to-face and distance teaching practices.
Neo-Liberalism and Change in Higher Education Policy: England and Japan
Authors: Yokoyama Keiko
Published: March 2008

The study scrutinizes the rationale behind higher education policy change in England and Japan, giving attention to stakeholders’ perspective and legitimacy, policy network, and policy sphere. It argues that change in higher education policy in England and Japan towards being more market-oriented in the 1980s (England) and the 1990s (Japan) can be commonly explained by the government's application of neo-liberal policy. The details in the political rationale for such policy change differ between the two. In England, change in the Government's values and perspective caused the policy change, while in Japan, enlargement of the policy sphere by incorporating non-education sub-government in the policy-making structure and the conflict and compromise between neo-liberal and anti-neoliberal groups resulted in the Government's policy change. The methods of data collection applied in the study were documentation and semi-structured interviews with selected stakeholders involved in the two higher education systems. The study suggests that not only change in the main stakeholders’ values but also that in the policy network is significant in policy change.
Autonomy of (Vocational) Schools as an Answer to Structural Changes
Authors: Spöttl Georg
Published: March 2008

In Europe a very intensive discussion is in full swing as to whether vocational schools should in future be guided and monitored by the state or whether they should be freed from state dependency. Within the framework of a number of pilot projects in German-speaking countries, vocational school centres are currently testing their autonomy. This article sketches out the discussion on a way forward.

Adopting a learner-centred perspective showed that formal education and training provide only a small part of what is learned at work. Most of the learning described by the interviewees was non-formal, neither clearly specified nor planned. It arose naturally out of the demands and challenges of work, solving problems, improving quality and/or productivity, or coping with change – and out of social interactions in the workplace. The outcome of such ‘learning from experience’ was the development of knowledge, skills and understanding, although this was difficult to explain to others. Effective learning was, however, dependent on confidence, motivation and capability – prerequisites for employees’ self-management of much of their learning. (Michael Eraut et al, 1998, p. 10ff).
Staging the Performances of the Privileged Social Group (PSG): Expanding the Philosophical Foundation of Critical Pedagogy
Authors: Graham Scott
Published: March 2008

Contemporary efforts to rethink the philosophical foundation of critical pedagogy are part of the ongoing project to make the field relevant to current struggles against oppression. Inherent to this project is an invitation to account for the plurality of ways and spaces in which privilege is performed in North American society and the troubling relations between privilege and oppression. The author employs Iris Young's social group concept to frame the construction of the Privileged Social Group (PSG), which, he contends, is a collectivity that has and continues to create relations to Others that systematically result in a range of social benefits for PSG members. The author defines the PSG through an analysis of its social position and the relational performances that it enacts to claim and maintain privilege. Three distinct social contexts in which the PSG is active are also examined, as well as two group control techniques through which PSG members influence one another's beliefs and behaviour for the purpose of claiming privilege as a group.
Nonlinear wave interactions in patterned Silica and AlGaAs waveguides
Authors: Linzon Yoav , Malomed Boris , Zaezjev Michael , Morandotti Roberto , Volatier Maite , Aimez Vincent , Ares Richard , Bar-Ad Shimshon
Published: March 2008

We study nonlinear interactions between discrete optical solitons that propagate in different regimes of diffraction, and the nonlinear scattering of dispersive waves by local optical potentials. It is well known in optics that when linear coherent waves meet, they interfere without interactions. Linear waves also scatter through local optical structures not exchanging any power with the guided modes of these structures. As a focusing Kerr nonlinearity is present, such linearly-inhibited phenomena can exist. Our studies are performed in silica and AlGaAs nonlinear waveguides, excited by ultra-short pulses in the near infrared.
Getting Started: Initializing “Organization” Around New Technology
Authors: Faia‐Correia Manuela , Pina E. Cunha Miguel
Published: March 2008

Our research analyzes how organization dynamics develop in order to initialize telebanks, which can facilitate (or hinder) the enactment of enabling (or coercive) structures. The data revealed that sometimes actors accept the constraints of social roles and technology and, at other times, they exercise agency to circumvent those constraints. The differences in organizational development are explained with the concept of bricolage and the structural characteristics that facilitate its occurrence. A culture supportive of learning and perceptions of psychological safety were found to be preconditions for enabling organizing, in that they increase the deployment of previously acquired knowledge, resources, and routines; facilitate the enactment of design and planning; and nurture improvisation and bricolage, thus increasing familiarity with resources and the willingness of people to actively participate in the organization’s design.
Workplace Spirituality, Commitment, and Self‐Reported Individual Performance: An Empirical Study
Authors: Rego Arménio , Pina E. Cunha Miguel , Souto Solange
Published: March 2008

This paper shows how the perceptions of people regarding five dimensions of workplace spirituality (team’s sense of community, alignment with organizational values, sense of contribution to society, enjoyment at work, and opportunities for inner life) predict affective, normative, and continuance commitment, as well as self‐reported individual performance. One sample in Portugal and another in Brazil were collected. The findings show that employees’ perceptions of workplace spirituality predict significant variance of commitment and individual performance in both samples. The empirical evidence suggests that workplace spirituality is a pertinent construct for researchers and an important concern to be taken into account by managers.
Mapping the Complexity of Knowledge Management Thought in Technology Management: A Critical Review of Information Systems Studies
Authors: Salazar Angel J.
Published: March 2008

Knowledge management has increasingly been regarded as an important research theme in information systems studies, with a substantial accumulated stock of empirical research. The purpose of this paper is to compare and contrast theoretical and methodological approaches to knowledge management in extant information systems studies. In so doing, the author builds a new typology and discusses relevant research questions and fundamental ontological and epistemological assumptions about the nature and study of social sciences, and the nature and scope of organizational knowledge. Previous typologies have tangled together basic assumptions about the nature and study of social sciences and the “transformative” nature and scope of organizational knowledge. The present typology acknowledges that these two dimensions need to be untangled to be able to discriminate and analyze fundamental assumptions that researchers, explicitly or implicitly, adopt in the study of knowledge management and information systems in organizations. This distinction is necessary because the implementation and use of information systems has the potential to enhance, or hinder, the transformative attributes or characteristics of organizational processes. This new typology is used to conceptualize, categorize, and criticize a sample of selected research articles, and to suggest new directions for research.
Incidence of Chondral Lesions of Talar Dome in Ankle Fracture Types
Authors: Aktas Seref , Kocaoglu Baris , Gereli Arel , Nalbantodlu Ufuk , Güven Osman
Published: March 2008

Background: Although the surgical treatment of ankle fractures is well known, a paucity of literature exists correlating chondral lesions with ankle fracture types. Materials and Methods: This study is a retrospective review of patients with absence or presence of chondral lesions that underwent arthroscopically assisted open reduction and internal fixation between June 2002 and April 2005. There were 38 female and 48 male patients (mean age, 41.4 years; mean followup, 33.9 months), and all had an Ankle-Hindfoot Scale score. The relationship between fracture types and presence of lesions was evaluated. Results: Four of 27 fractures with chondral lesions consisted of the bimalleolar type, 6 of 15 fractures with chondral lesions consisted of the trimalleolar type, and 14 of 20 distal fibula fractures had chondral lesions. There was significant greater incidence of chondral lesions associated with distal fibula fractures. The mean AOFAS score was 95.6 among all fractures. Conclusion: There is clear evidence that despite anatomic reduction, postoperative results of ankle fracture repair are not free of complications. We believe inspection of the talar dome should be routinely considered in the surgical repair ankle fractures.
Modes of Engagement in Foreign Language Writing: An Activity Theoretical Perspective
Authors: Haneda Mari
Published: March 2008

Abstract:

This article makes the case for using activity theory to explore the learning and teaching of writing in a foreign language. I illustrate my argument by bringing this theory to bear on a re-examination of the different modes of engagement in writing by university-level students of Japanese as a foreign language that I identified in an earlier study. The first half of the article develops a perspective on writing as a social activity/practice, building on an interdisciplinary body of work and focusing particularly on activity theory. The different modes in which students engaged in writing in my earlier study are then interpreted from this perspective. I examine these modes both synchronically and diachronically in order to explore the students’ underlying values and attitudes with respect to learning the target language, suggesting that an activity-theoretical perspective can be a useful heuristic for the systematic detection of problems in writing that foreign language learners may encounter, so that instruction can be tailored to their needs.
The More Knowledgeable Peer, Target Language Use, and Group Participation
Authors: Huong Le Pham Hoai
Published: March 2008

Abstract:

Vygotsky proposed the concept of the zone of proximal development (ZPD) but did not elaborate the concept of ‘peer,’ leaving open the question of how capable a peer should be and how practice or outcome might differ according to a peer's level of capability. These issues were investigated in a sociocultural study of first-year Vietnamese university students learning English. The students were examined in two group settings, ‘unassisted’ and ‘assisted,’ the first consisting of five students from the same class and the second of four from the same class and a more knowledgeable student from a higher class. The senior student made a marked difference to the organization of the assisted group's processes: she helped the other students start their discussions, explained new English words, and increased the use of English in this group setting. The results suggest that the teaching manner of the senior student contributed substantially to the group work in the current study.
Changes in the field‐layer of Wytham Woods ‐ assessment of the impacts of a range of environmental factors controlling change
Authors: Corney P.M. , Kirby K.J. , Le Duc M.G. , Smart S.M. , McAllister H.A. , Marrs R.H.
Published: March 2008

Question:

What are the impacts of factors controlling patterns of change in woodland field‐layer vegetation, through time?

Location:

Wytham Woods, Oxford, UK (51°4i'N, 1°19'W).

Methods:

Species occurrence was monitored in 163 permanent plots three times between 1973 and 2002 and related to management compartment and history. The dataset was analysed using a combination of ordination methods, univariate and multivariate analysis of variance and HOF modelling.

Results:

The two key findings of this paper are: (1) that the species composition of ancient woodlands (often cited as a conservation goal), may be moving along an‘undesirable’trajectory, from a conservation viewpoint; and (2) that the impact of a synergistic effect of changing canopy dynamics, nitrogen deposition and a rising deer population has resulted in an increase in grass species, at the expense of woodland herbs. These findings have significant implications for the practical conservation of similar habitats across Europe.

Conclusions:

The analytical methodology presented here allowed detailed assessment of the potential roles of a range of environmental factors controlling change. The methodology may be applicable to other long‐term studies of vegetation, and is particularly appropriate for identification of cross‐site drivers, such as pollutant load and climate change.
Continuous Aspect‐Ratio Tuning and Fine Shape Control of Monodisperse α‐Fe2O3 Nanocrystals by a Programmed Microwave–Hydrothermal Method
Authors: Hu Xianluo , Yu Jimmy C.
Published: March 2008

A rapid and economical route based on an efficient microwave–hydrothermal process has been developed to synthesize monodisperse α‐Fe2O3 nanocrystals with continuous aspect‐ratio tuning and fine shape control, which takes advantage of microwave irradiation and hydrothermal effects. This method easily programs the experimental conditions (e.g., temperature and time) and significantly shortens the synthesis time to minutes. It allows the creation of numerous recipes for optimizing and scaling up production. The effects of experimental conditions including reaction temperature and reactant concentration on the morphology of α‐Fe2O3 have been investigated systematically. Results reveal that the initial molar ratio of Fe3+ to PO plays a crucial role in the final morphology of the α‐Fe2O3 products. Several morphologies, which include ellipsoids/spindles with aspect ratios that range from 1.1 to 6.3, nanosheets, nanorings, and spheres can be obtained. The as‐formed α‐Fe2O3 exhibits shape‐dependent infrared optical properties. The growth process of colloidal α‐Fe2O3 crystals in the presence of phosphate ions is discussed. The products have been characterized by using X‐ray diffraction, scanning electron microscopy, transmission electron microscopy, and infrared spectroscopy. This work presents an efficient and cost‐effective approach that is potentially competitive for scaling‐up industrial production. The as‐formed α‐Fe2O3 crystals with controllable morphologies not only provide flexible building blocks for advanced functional devices, but are also ideal candidates for studying their nanoarchitecture‐dependent performance in optical, catalytic, and magnetic applications.
Self‐assembled Cationic Peptide Nanoparticles Capable of Inducing Efficient Gene Expression In Vitro
Authors: Wiradharma Nikken , Khan Majad , Tong Yen Wah , Wang Shu , Yang Yi‐Yan
Published: March 2008

In this study, cationic and amphiphilic oligopeptides, (A)12(H)5(K)10 (AK27) and (A)12(H)5(K)15 (AK32), were designed and tested as a nonviral gene vector. The oligopeptides had critical micelle concentrations (CMC) of 0.9 and 1.1 mg mL−1 respectively, indicating that they were able to self‐assemble into core–shell nanoparticles at concentrations above the CMC value, which was confirmed by electron microscopy. The nanoparticles were cubic and had an effective diameter of 700–900 nm, as well as a zeta potential of 18 to 20 mV. The formation of nanoparticles increased the local concentration of cationic charge in the solution, leading to improved DNA binding ability and better protection from enzymatic degradation compared to the control peptide (H)5(K)10 (HK15) without a hydrophobic block. The smallest effective diameters of AK27–DNA and AK32–DNA complexes were 442 and 332 nm, respectively, and the highest zeta potentials were 7.8 and 18.2 mV, respectively. In comparison, HK15 formed much larger DNA complexes with a nearly neutral zeta potential. Cytotoxicity tests showed that HEK293, HepG2, and 4T1 cell lines had viabilities of more than 80% after incubation with AK27 and AK32 peptides, which was much higher than that obtained from polyethyleneimine (PEI) incubation. Furthermore, an increased length of lysine block, and the presence of the hydrophobic block did not show any significant increase in cytotoxicity. More importantly, AK27 and AK32–DNA complexes induced much higher luciferase expression efficiency than KH15 in all three cell lines tested. AK32 with a longer lysine block led to more efficient gene expression than AK27. In addition, the gene‐expression levels mediated by AK32 nanoparticles were comparable to those provided by PEI, especially in HepG2 and 4T1 cell lines. These cationic nanoparticles made from biodegradable and biocompatible peptides may provide a promising carrier for gene delivery.
A Facile Strategy for Preparation of Fluorescent SWNT Complexes with High Quantum Yields Based on Ion Exchange
Authors: Fu Chuanlong , Meng Lingjie , Lu Qinghua , Fei Zhaofu , Dyson Paul J.
Published: March 2008

The fluorescent imidazolium salt (1,3‐bis(9‐anthracenylmethyl)imidazolium chloride, [bamim]Cl) has been grafted onto the surfaces of single‐walled carbon nanotubes (SWNTs) using an ion exchange strategy based on metathesis of the K+ ion in CO2K derivatized SWNTs with [bamim]+. The resulting SWNT‐[bamim] complex has been characterized with high‐resolution transmission electron microscopy (HR‐TEM), X‐ray photoelectron spectroscopy (XPS), elemental mapping, and elemental linear profiles analysis. A blue light emission can be observed at 392, 414 and 438 nm for SWNT‐[bamim] upon being excited at 254 nm. The quantum yield (QY) of the SWNT‐[bamim] complex (0.40) is much higher than that of SWNT/[bamim]Cl (0.02), used as a control, and prepared using a π‐π stacking method, indicating that ion exchange is a far more effective strategy for retaining a high QY. Additionally, UV‐Vis‐NIR and Raman spectroscopy show that the SWNT‐[bamim] complex can maintain the one‐dimensional electronic states of SWNTs. Other imidazolium salts have also been successfully grafted onto SWNTs via the same strategy, indicating that the ion exchange process can serve as a universal strategy for the functionalization of SWNTs.
Evaluation of juvenile stature and body mass prediction
Authors: Sciulli Paul W. , Blatt Samantha H.
Published: March 2008

This investigation evaluates the performance of juvenile stature (from tibia and radius lengths) and body mass (from breadth of the femoral distal metaphysis) prediction equations based on the Denver Growth Study sample (Ruff C. 2007. Am J Phys Anthropol 133 698–716). The sample used here for evaluation is an independent sample of juveniles brought to the Franklin County (Ohio) Coroner in 1990–1991. The Ohio sample differs somewhat from the Denver reference sample: it includes ∼25% African‐Americans (rather than all European‐Americans), a significant number of right limb bones were measured (rather than all left side), it includes a wider range of economic statuses and it includes individuals who died from disease and trauma. As such the composition and measures of the Ohio sample correspond more generally to that seen in skeletal samples so that the accuracy of the estimates from the present sample should approach those found in practical applications of these methods. Results indicate that both juvenile body mass and stature are estimated relatively accurately. Accuracy of body mass estimates for 1‐13‐year‐old juveniles is similar for African‐American and European‐American males and females. The least accurate estimates are for individuals in the 8–13 years age class (excluding individuals with body mass indices greater than the age specific 95th percentile): n = 9, ± 2.9 kg, 95% confidence interval 1.4–4.4 kg. Accuracy of stature estimates for 1‐17‐year‐old juveniles is comparable for the tibia and radius and, as with body mass estimates, are similar for African‐American and European‐American males and females. For combined age, sex, and ancestry groups average accuracies are in the ±3.5 to ±6.5 cm range. Some limitations of the methods are discussed. Am J Phys Anthropol, 2008. © 2008 Wiley‐Liss, Inc.
Cell‐specific alterations of glutamate receptor expression in tuberous sclerosis complex cortical tubers
Authors: Talos Delia M. , Kwiatkowski David J. , Cordero Kathia , Black Peter M. , Jensen Frances E.
Published: March 2008

Objective

Genetic loss ofTSC1/TSC2function in tuberous sclerosis complex (TSC) results in overactivation of the mammalian target of rapamycin complex 1 pathway, leading to cellular dysplasia. We hypothesized that the dysplastic cells in TSC tubers are heterogeneous, including separable classes on a neuronal‐glial spectrum, and that these dysplastic cells express glutamate receptor (GluR) patterns consistent with increased cortical network excitability.

Methods

Surgically resected human cortical tubers and nondysplastic epileptic cortical samples were analyzed by double‐label immunocytochemistry for coexpression of neuronal and glial markers, the TSC1/TSC2 pathway downstream molecule phospho‐S6 (pS6) and GluR subunits, and compared with control cortical tissue. Western blotting was used to quantify changes in GluR subunit expression in tubers versus controls.

Results

We demonstrate that cortical tubers contain a broad spectrum of cell types including disoriented pyramidal cells, dysplastic neurons, giant neuroglial cells, dysplastic astroglia, and reactive astrocytes. Dysplastic neurons, giant cells, and dysplastic astroglia express high levels of pS6 and demonstrate altered GluR subunit composition, resembling those of normal immature neurons and glia. In contrast, nondysplastic neurons in TSC and non‐TSC epileptic lesions express lower pS6 levels and display changes in GluR subunit expression that are distinct from the patterns seen in tuber dysplastic cells.

Interpretation

This work significantly expands the spectrum of abnormal cells recognized in tubers beyond the classic tuber giant cell and demonstrates cell‐specific abnormalities in GluR expression that may contribute to seizure pathogenesis in TSC. Furthermore, these results suggest that subunit‐specific antagonists may be of potential use in the treatment of epilepsy in TSC. Ann Neurol 2008
Combinatorial Transition‐Metal Catalysis: Mixing Monodentate Ligands to Control Enantio‐, Diastereo‐, and Regioselectivity
Authors: Reetz Manfred T.
Published: March 2008

This review focuses on a new approach to combinatorial homogeneous transition‐metal catalysis which goes beyond the traditional parallel preparation of modular ligands. It is based on the use of mixtures of monodentate ligands La and Lb, which upon exposure to a transition metal (M) form not only the two homocombinations [MLaLa] and [MLbLb], but also the heterocombination [MLaLb]. If the latter is more reactive and selective than the homocombinations, an improved catalyst system is formed without the need to synthesize new ligands. Thus, the control of enantio,‐ diastereo‐, and regioselectivity is possible.
Influence of ozone on chemical reactions during the stabilization of polyacrylonitrile as a carbon fiber precursor
Authors: Hou Yongping , Sun Tongqing , Wang Haojing , Wu Dong
Published: March 2008

Chemical shrinkage was used for the in situ measurement of the progressing chemical stabilization reactions and the influence of ozone during the stabilization of polyacrylonitrile. A method for evaluating the activation energy through the sensitivity temperature is presented. The calculated results show that the activation energies were 161.57 kJ/mol in air and 181.23 kJ/mol in ozone‐enriched air. Therefore, the chemical reactions were postponed during stabilization in ozone‐enriched air. Ozone seemed to act in three ways: first, ozone promoted the formation of the serious skin–core structure. Second, ozone accelerated the chemical reactions and shortened the stabilization time at lower heating rates. Third, ozone postponed the chemical reactions. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci 2008
Moisture absorption behavior of epoxies and their S2 glass composites
Authors: Chatterjee Amit , Gillespie John W.
Published: March 2008

The influence of moisture exposure on the behavior of three toughened epoxy–amine systems (scrimp resins SC11, SC15, and SC79, Applied Poleramic, Inc., Benicia, CA) was investigated. Neat resin samples were conditioned by immersion in distilled water at 71°C and in an environmental chamber at 85% relative humidity and 87.8°C until saturation. The equilibrium weight gain ranged from 1.8 to 3.8% for the resins. The long‐chain, low‐crosslink‐density epoxy system (SC11) absorbed the highest amount of water and was saturated first, and it was followed by the medium‐crosslink‐density (SC15) and high‐crosslink‐density materials (SC79). The moisture diffusivity decreased with the increasing crosslink density of the resins. The percentage reduction of the glass‐transition temperature (Tg) at equilibrium moisture absorption was highest for the low‐crosslink molecule. The percentage reductions for the medium‐crosslink and higher crosslink systems were comparable. A net weight loss after drying was observed for the SC11 and SC79 resin systems. Fourier transform infrared analysis confirmed the segment breakage and leaching of molecules from the epoxy–amine network. The effects of moisture cycling on Tg were dependent on the epoxy–amine morphology. During the drying stage, Tg increased to a value higher than that of the unaged dry systems. The S2 glass composite samples were conditioned under identical conditions for the resin system. Composite systems absorbed less moisture than the neat resins as expected. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci 2008
HPLC‐fluorescence assay for acyclovir in children
Authors: Zeng L. , Nath C. E. , Shaw P. J. , Earl J. W. , McLachlan A. J.
Published: March 2008

A simple, accurate, reliable and sensitive HPLC method was developed and validated for quantitating acyclovir in human plasma. Sample (100 µL) preparation involved addition of guanosine (internal standard) and protein precipitation with 7% perchloric acid and centrifugation. Supernatant (20 µL) was injected onto a C18 HPLC column with a mobile phase of 0.05 m sodium phosphate buffer–acetonitrile (pH 2.35, 992:8, v/v) with 25 µL of 0.4 m tetrabutylammonium hydroxide titrant and fluorescence detection (excitation, 260 nm; emission, 375 nm). Analyte recovery was 101% and the assay response was linear over the acyclovir concentration range of 0.1–20 mg/L. Intra‐ and inter‐day accuracy and precision were less than 7%. The limit of detection and limit of quantitation were 0.033 and 0.1 mg/L, respectively. In five paediatric oncology patients administered intravenous acyclovir, concentrations ranged from 0.24 to 43.65 mg/L. This method can be used to measure acyclovir concentrations in paediatric patients. Copyright © 2008 John Wiley & Sons, Ltd.
Organobentonite as Efficient Textile Dye Sorbent
Authors: Jović‐Jovičić N. , Milutinović‐Nikolić A. , Gržetić I. , Jovanović D.
Published: March 2008

Domestic bentonite clay was modified using cationic surfactant – hexadecyltrimethylammonium bromide (HDTMA‐bromide) in order to obtain more efficient sorbent. Removal of Acid Orange 10 from aqueous solution at different dye concentrations, adsorbent doses, and pH was studied. These studies were carried out under unaltered pH value in order to prove that adjusting pH as an additional operation in wastewater treatment is not entirely necessary. The results obtained confirmed the adsorption capacity is significant even for unaltered pH. The adsorption isotherm data were well fitted with both the Freundlich and Langmuir model and the latter was shown as more appropriate. Dynamical data were well represented with the pseudo second‐order kinetic model. The results indicate that HDTMA‐bentonite could be employed as low‐cost sorbent in textile dye wastewater treatment.
Removal of SO2 Using a Magnetically Fluidized Bed in the Semi‐Dry Flue Gas Desulfurization Process: Roles of Ferromagnetic Particles and Applied Magnetic Field in the Desulfurization Reaction
Authors: Zhang Q. , Gui K.‐T.
Published: March 2008

A new semidry flue gas desulfurization (FGD) process is proposed. The process uses a magnetically fluidized bed (MFB) as the reactor in which ferromagnetic particles are fluidized with simulated flue gas under the influence of an external magnetic field. A slurry of lime is continuously sprayed into the reactor by an atomizer fixed at the top of the bed. As a consequence, the desulfurization reaction and slurry drying take place simultaneously in a same reactor. Experiments with a laboratory‐scale apparatus were carried out to investigate the roles of the ferromagnetic particles and the magnetic field applied in the desulfurization reaction. The results show that when ferromagnetic particles are used as the fluidization material, both sulfite (SO32–) salts and sulfate (SO42–) salts are found in the desulfurization products. When quartz particles are used, only sulfite (SO32–) salts are found. This suggests that the Fe(III) ions and Fe(II) ions result from the ferromagnetic particles dissolving in the liquid phase. In addition, the ions act as catalysts in the oxidation of S(IV) to S(VI) and react with SO2 producing FeSO3 and Fe2(SO4)3 as the products. On the other hand, the level of the sulfate (SO42–) salts in the products increases with increasing intensity of applied field intensity, which suggests that the oxidation of S(IV) can be enhanced by the applied magnetic field. The oxidation of S(IV) can increase the solubility of SO2, and therefore, intensify the reaction between SO2 and Ca(OH)2, leading to an increased SO2 removal efficiency.