bluuebunny/crossref_metadata_2025 huggingface dataset:
Aleppo Pine Bark as a Biomonitor of Atmospheric Pollution in the Arid Environment of Jordan
Authors: Al‐Alawi Mu'taz M. , Batarseh Mufeed I. , Carreras Hebe , Alawi Mahmoud , Jiries Anwar , Charlesworth Susanne M.
Published: November 2007

Monitoring of atmospheric pollution using Aleppo bark as a bioindicator was carried out in the industrial area surrounding the Al‐Hussein thermal power station and the oil refinery at Al‐Hashimyeh town, Jordan. The concentrations of heavy metals (copper, lead, cadmium, manganese, cobalt, nickel, zinc, iron, and chromium) were analyzed in bark samples collected from the study area during July 2004. The results showed that high levels of heavy metals were found in tree bark samples retrieved from all studied sites compared with the remote reference site. This is, essentially, due to the fact that the oil refinery and the thermal power plant still use low‐quality fuel oil from the by‐products of oil refining. Automobile emissions are another source of pollution since the study area is located along a major heavy‐traffic highway. It was found that the area around the study sites (Al‐Hashimyeh town, Zarqa) is polluted with high levels of heavy metals. Pine bark was found to be a suitable bioindicator of aerial fallout of heavy metals in arid regions.
Thinking in Structure‐Activity Relationships – A Way Forward Towards Sustainable Chemistry
Authors: Jastorff Bernd , Störmann Reinhold , Ranke Johannes
Published: November 2007

Thinking in structure‐activity relationships (T‐SAR) is presented as an approach to a systematic collection and networking of knowledge and hypotheses regarding chemical structures. T‐SAR can be accompanied by quantitative correlation studies commonly referred to as quantitative structure‐activity relationships (QSAR) or linear free energy relationships (LFER). Some important limitations of these quantitative approaches are illustrated using the examples of biopartitioning and equilibrium partitioning in general. A systematic scheme for the qualitative analysis of a structural formula in seventeen steps is shown, covering stereochemistry, molecular interaction potentials, and reactivity. As an example for the application of T‐SAR, contributions to the molecular design of ionic liquids are described.
Fate of the Benzimidazole Antiparasitics Flubendazole and Fenbendazole in Manure and Manured Soils
Authors: Kreuzig Robert , Blümlein Katharina , Höltge Sibylla
Published: November 2007

The fate of flubendazole and fenbendazole in manure and manured soils was investigated under laboratory and field conditions. In pig manure, both 14C‐labeled benzimidazoles disappeared slowly. After a 102 day incubation period, extractable fractions contained 72% flubendazole or 80% fenbendazole of the radioactivity initially applied. The latter was accompanied by 4% of the corresponding metabolite fenbendazole‐sulfoxide. Non‐extractable residues amounted to 24 and 13%, respectively. On this basis, test manures with 7 day aged benzimidazole residues were prepared. Mobility tendencies differed for clay and sand soils as well as for standard and test‐manure application. Regarding KOC > 1100 L/kg, however, criteria for potential leachers were not fulfilled. The metabolic fate of flubendazole was predominated by the occurrence of the parent compound while fenbendazole was accompanied by fenbendazole‐sulfoxide. In clay soil samples after standard application, DT50 values were 174 and 54 days, respectively. Mineralization and formation of non‐extractable residues were of minor relevance. For fenbendazole, these processes were intensified after test‐manure application. Due to enhanced formation of fenbendazole‐sulfoxide, fenbendazole‐sulfone, and non‐extractable residues, DT50 thus dropped to 9 days. Similar mobility and degradability tendencies were also found under field conditions. In the sand soil, however, the metabolic dynamics decelerated due to its lower microbial activity.
Ecologically Benign Lubricants – Evaluation From a Life Cycle Perspective
Authors: Herrmann Christoph , Hesselbach Jürgen , Bock Ralf , Zein André , Öhlschläger Gerlind , Dettmer Tina
Published: November 2007

Using mineral oil based coolants for the machining of metals causes environmental problems. Besides plant seed oil, animal fat and used cooking oil proved to be raw material sources for alternative ester based coolants which can be used as substitutes for mineral oil. In this paper their properties are compared from a life cycle perspective with those of mineral oil and plant seed oil ester products regarding technical, ecological and economical aspects. In this context grinding tests, Life Cycle Assessment and Life Cycle Costing were performed. The three disciplines are brought together in a material flow model and, therefore, results are well harmonized.
Targeting cytotoxic T‐lymphocyte antigen‐4 (CTLA‐4)
Authors: O'Day Steven J. , Hamid Omid , Urba Walter J.
Published: November 2007

Cancer immunotherapy centers on modulating the host's tumor‐directed immune response. One promising approach involves augmentation of cell‐mediated immunity by interrupting T‐cell pathways responsible for immune down‐regulation or tolerance. The discovery of cytotoxic T‐lymphocyte antigen‐4 (CTLA‐4) and its role as a key negative regulator for T cells has prompted efforts to target this signaling molecule to improve cancer therapy. Activation, or ‘priming’, of naive T cells in response to tumor‐cell invasion comprises a dual‐signaling mechanism. Signal 1 requires tumor‐associated antigen recognition by the T‐cell receptor, while signal 2 occurs through binding of CD80 or CD86 (B7.1 of 2) on the antigen presenting cell (APC) with CD28 on the T cell. Importantly, there is a final step responsible for naturally occurring immune regulation; this occurs in response to competitive binding of CD80/CD86 on the APC by CTLA‐4 on the T cell. This ‘immune checkpoint’ interrupts signal 2 and inhibits the activated T cell. Targeting CTLA‐4 as an anticancer strategy: Following proof‐of‐concept studies in animals, fully human anti‐CTLA‐4 antibodies were developed and 2 are undergoing clinical evaluation. Ipilimumab and tremelimumab have shown promising antitumor activity, initially in patients with advanced melanoma. Class‐specific immune‐related adverse events (irAEs) were common and mostly transient and/or manageable. These events are thought to be mechanism‐of‐action‐related, indicating immune tolerance is broken; this relation may also explain the association between irAEs and response seen in several trials. Interruption of immune inhibitory pathways via CTLA‐4 blockade appears to be a promising strategy for cancer immunotherapy. Cancer 2007. © 2007 American Cancer Society.
Two‐Photon Absorption Properties of Dehydrobenzo[12]annulenes and Hexakis(phenylethynyl)benzenes: Effect of Edge‐Linkage
Authors: Kamada Kenji , Antonov Liudmil , Yamada Satoru , Ohta Koji , Yoshimura Takashi , Tahara Kazukuni , Inaba Akiko , Sonoda Motohiro , Tobe Yoshito
Published: November 2007

Two‐photon absorption (TPA) properties of two trefoil‐shaped compounds with different edge linkages—tris(hexadehydrotribenzo[12]annulene) and tris(tetradehydrotribenzo[12]annulene)—and three asterisk‐shaped compounds having no edge‐linkage—hexakis(phenylethynyl)benzenes—are investigated experimentally by the open‐aperture Z‐scan and TPA‐induced fluorescence methods with wavelength tuneable femtosecond pulses. The compound with ethynylene edge‐linkage exhibits the most intense TPA (the maximal TPA cross section is 1300±170 GM at 572 nm where 1 GM=10−50 cm4 s molecule−1 photon−1). The TPA activity of the compounds is primarily explained in terms of the planarity of the molecules in relation with the type of edge‐linkage.
Promiscuous gene expression and the developmental dynamics of medullary thymic epithelial cells
Authors: Gäbler Jana , Arnold Janna , Kyewski Bruno
Published: November 2007

Thymic epithelial cells (TEC) form the structural and functional microenvironment necessary for the establishment and quality control of the T cell repertoire. In addition, they provide an ectopic source of numerous tissue‐restricted antigens (TRA), a feature called promiscuous gene expression (pGE). How the regulation of pGE is related to the cell biology of TEC subset(s), e.g. their turnover and developmental interrelationship is still poorly understood. The observation that pGE is foremost a property of phenotypically and functionally mature medullary TEC (mTEC) implies that the full implementation of pGE is contingent on mTEC differentiation. Here, we show that the emergence of TEC subsets and pGE is tightly correlated during ontogeny and we provide evidence that mature CD80pos mTEC develop from an immature CD80neg subset. This differentiation step proceeds continuously in the postnatal thymus. While mature mTEC turnover in 2 to 3 weeks, immature mTEC encompass a smaller cycling and a larger non‐cycling pool. The latter might serve as a reservoir of committed precursors, which sustain this renewal process. Our data document that mTEC represent a highly dynamic cell population, and they imply that the availability and display of TRA in the thymus undergoes a perpetual temporal and spatial reorganization.
Induction and protective role of antibodies in Legionella pneumophila infection
Authors: Joller Nicole , Spörri Roman , Hilbi Hubert , Oxenius Annette
Published: November 2007

Legionella pneumophila (Lpn) is a ubiquitous Gram‐negative bacterium found in aquatic environments and is the causative agent of Legionnaires’ disease, a severe form of pneumonia. We have used Lpn‐permissive A/J mice as a model to analyze the B cell response upon intravenous (i.v.) and intranasal (i.n.) infection with Lpn. A strong antibody (Ab) response was observed upon i.v. infection with wild‐type (WT) Lpn and an icmT mutant strain, which is unable to replicate within permissive host cells. In contrast to i.v. infection, only WT but not icmT mutant Lpn was able to induce specific Ab responses upon i.n. infection. After primary i.n. infection with WT Lpn, a strict compartmentalization of Lpn‐specific Ab isotypes was observed, as IgG was found exclusively systemically, while IgA was detectable only locally in the lung. Regardless of the infection route, isotype switching to IgG and to IgA was strictly dependent on CD4+ T cells, whereas IgM production was completely Th‐independent. Finally, we analyzed the protective capacity of the Lpn‐specific Ab response. Actively or passively immunized mice or mice that were infected with opsonized Lpn had 50–100‐fold reduced bacterial titers compared to naive animals, clearly demonstrating the capacity of Ab to protect against infection with Lpn.
Innate responses of B cells
Authors: Gray David , Gray Mohini , Barr Tom
Published: November 2007

In this review, we describe the non‐antibody‐mediated functions of B cells within the immune system. In addition to antibody production, B cells also present antigen to T cells, programme T cell differentiation and regulate effector T cell responses and much of this is mediated by the cytokines they make. We focus on the potential of B cells to perform these functions simply as a result of activation via ‘innate’ receptors (e.g. Toll‐like receptors) and often independently of BCR ligation. We feel an appreciation of these broad and often antigen‐nonspecific functions is important at a time when there is an increasing use of B cell depletion as a therapy for autoimmune disease.
Mapping immune response profiles: The emerging scenario from helminth immunology
Authors: Díaz Alvaro , Allen Judith E.
Published: November 2007

Metazoan parasites of mammals (helminths) belong to highly divergent animal groups and yet induce a stereotypical host response: Th2‐type immunity. It has long been debated whether this response benefits the host or the parasite. We review the current literature and suggest that Th2 immunity is an evolutionarily appropriate response to metazoan invaders both in terms of controlling parasites and repairing the damage they inflict. However, successful parasites induce regulatory responses, which become superimposed with, and control, Th2 responses. Beyond helminth infection, this superimposition of response profiles may be the norm: both Th1 and Th2 responses coexist with regulatory responses or, on the contrary, with the inflammatory Th17 responses. Thus, typical responses to helminth infections may differ from Th2‐dominated allergic reactions in featuring not only a stronger regulatory component but also a weaker Th17 component. The similarity of immune response profiles to phylogenetically distinct helminths probably arises from mammalian evolution having hard‐wired diverse worm molecules, plus tissue‐damage signals, to the beneficial Th2 response, and from the convergent evolution of different helminths to elicit regulatory responses. We speculate that initiation of both Th2 and regulatory responses involves combinatorial signaling, whereby TLR‐mediated signals are modulated by signals from other innate receptors, including lectins.
Electroactive intercalators for DNA analysis on microchip electrophoresis
Authors: Castaño‐Álvarez Mario , Fernández‐Abedul M. Teresa , Costa‐García Agustín
Published: November 2007

Miniaturized analytical systems, especially microchip CE (MCE), are becoming a promising tool for analytical purposes including DNA analysis. These microdevices require a sensitive and miniaturizable detection system such as electrochemical detection (ED). Several electroactive DNA intercalators, including the organic dye methylene blue (MB), anthraquinone derivatives, and the metal complexes Fe(phen)32+ and Ru(phen)32+, have been tested for using in combination with thermoplastic olefin polymer of amorphous structure (Topas) CE‐microchips and ED. Two end‐channel approaches for integration of gold wire electrodes in CE‐ED microchip were used. A 250 μm diameter gold wire was manually aligned at the outlet of the separation channel. A new approach based on a guide channel for integration of 100 and 50 μm diameter gold wire has been also developed in order to reduce the background current and the baseline noise level. Modification of gold wire electrodes has been also tested to improve the detector performance. Application of MCE‐ED for ssDNA detection has been studied and demonstrated for the first time using the electroactive dye MB. Electrostatic interaction between cationic MB and anionic ssDNA was used for monitoring the DNA on microchips. Thus, reproducible calibration curves for ssDNA were obtained. This study advances the feasibility of direct DNA analysis using CE‐microchip with ED.
Property of ionic liquid in electrophoresis and its application in chiral separation on microchips
Authors: Zeng Hu‐Lie , Shen Hui , Nakagama Tatsuro , Uchiyama Katsumi
Published: November 2007

The aqueous solution of a kind of room‐temperature ionic liquids (RTILs), 1‐ethyl‐3‐methylimidazolium‐tetrafluoroborate (1E‐3MI‐TFB), demonstrated its exclusive electroosmotic property in microchip electrophoresis. It was applied as the working electrolyte for chiral separation in glass microchip electrophoresis. Compared with boric acid buffer, 1E‐3MI‐TFB aqueous solution exhibited a broader separation window for enantiomers of dipeptides. Then the influences of chiral selector, pH and concentration on efficiency of chiral separation were discussed in detail. The unique mechanism of the generation of EOF was explored in a glass microchannel using 1E‐3MI‐TFB aqueous solution as working electrolyte. A possible status of 1E‐3MI cation in water was suggested at the first time, which facilitated the explanation of EOF and its characteristics in glass microchannel. Additionally, microchip electrophoresis using 1E‐3MI‐TFB aqueous solution was successfully applied to the chiral separation of complex enantiomers of dipeptides. RTILs aqueous solution, as the electrolyte for the separation of complicated optical isomers, could lead to a revolution in the analytical methods of chiral or conformational analysis for biomolecules.
Restoring capability of bilinear hysteretic seismic isolation systems
Authors: Katsaras Christos P. , Panagiotakos Telemachos B. , Kolias Basil
Published: November 2007

The restoring capability (or re‐centering capability) is identified by the current design codes as a fundamental feature of seismic isolation systems. In this paper, the restoring capability of bilinear hysteretic or frictional seismic isolation systems is investigated in some detail. Certain energy considerations are examined first in order to provide insight into and reveal governing parameters on individual aspects of the problem. The restoring capability is then investigated through an extensive parametric study of smooth bilinear single‐degree‐of‐freedom hysteretic systems, with parameters covering a range of typical seismic isolation systems, subjected to a large group of recorded earthquakes. The results of the parametric analyses are processed statistically and regression analysis relations are derived that show the dependence of the residual displacement after the earthquake and the cumulative build up of displacements after a series of successive earthquakes on the governing parameters. Based on the analysis results, the features of the bilinear system that ensure sufficient restoring capability are identified. Copyright © 2007 John Wiley & Sons, Ltd.
The extended switching regression model: allowing for multiple latent state variables
Authors: Preminger Arie , Ben‐zion Uri , Wettstein David
Published: November 2007

In this paper we extend the widely followed approach of switching regression models, i.e. models in which the parameters are determined by a latent discrete state variable. We construct a model with several latent state variables, where the model parameters are partitioned into disjoint groups, each one of which is independently determined by a corresponding state variable. Such a model is called an extended switching regression (ESR) model. We develop an EM algorithm to estimate the model parameters, and discuss the consistency and asymptotic normality of the maximum likelihood estimates. Finally, we use the ESR model to combine volatility forecasts of foreign exchange rates. The resulting forecast combination using the ESR model tends to dominate those generated by traditional procedures.  Copyright © 2007 John Wiley & Sons, Ltd.
Evaluation of correlation forecasting models for risk management
Authors: Skintzi Vasiliki D. , Xanthopoulos‐Sisinis Spyros
Published: November 2007

Reliable correlation forecasts are of paramount importance in modern risk management systems. A plethora of correlation forecasting models have been proposed in the open literature, yet their impact on the accuracy of value‐at‐risk calculations has not been explicitly investigated. In this paper, traditional and modern correlation forecasting techniques are compared using standard statistical and risk management loss functions. Three portfolios consisting of stocks, bonds and currencies are considered. We find that GARCH models can better account for the correlation's dynamic structure in the stock and bond portfolios. On the other hand, simpler specifications such as the historical mean model or simple moving average models are better suited for the currency portfolio.  Copyright © 2007 John Wiley & Sons, Ltd.
Plasma Sputtering Deposition of PEMFC Porous Carbon Platinum Electrodes
Authors: Rabat H. , Brault P.
Published: November 2007

A novel method is proposed to fabricate the active catalytic layers of proton exchange membrane fuel cells (PEMFC). A plasma sputtering technique is used to deposit a porous columnar carbon film (column diameter of 20 nm) followed by the catalyst (platinum) deposition directly on the proton‐conducting membrane. The study of Pt diffusion shows that the optimised catalysed layers correspond to low plasma pressure operation (0.5 Pa) below a platinum loading limit of about 90 μg cm–2. The initial carbon porosity is then maintained and Pt nanoparticles are present in all parts of the carbon layer. A membrane electrode assembly (MEA) is then achieved by alternate depositions of carbon and platinum onto both sides of the membrane. The results show the importance of the porous carbon structure. A significant increase in the catalyst efficiency is observed compared to a commercial fuel cell when measuring open circuit voltage.
Transplanted astrocytes internalize deposited β‐amyloid peptides in a transgenic mouse model of Alzheimer's disease
Authors: Pihlaja Rea , Koistinaho Jari , Malm Tarja , Sikkilä Herkko , Vainio Seppo , Koistinaho Milla
Published: November 2007

Alzheimer's disease (AD) is one of the most devastating neurodegenerative disorders. The neuropathological hallmarks include extracellular senile plaques consisting of deposited β‐amyloid (Aβ) peptides and intraneuronal neurofibrillary tangles. Neuroinflammation and activation of astrocytes are also well‐established features of AD neuropathology; however, the relationships between astrocytes and Aβ deposition remain unclear. Previous studies have shown that adult mouse astrocytes internalize and degrade Aβ deposits in brain sections prepared from human amyloid precursor protein (APP) transgenic mice. In the present study, we demonstrate that cultured adult, but not neonatal mouse astrocytes, respond morphologically and degrade Aβ deposits present in human AD brain. We also transplanted astrocytes isolated from enhanced green fluorescent protein expressing adult and neonatal mice into the hippocampi of human Aβ plaque‐bearing transgenic APPSwe+PS1dE9 (APdE9) mice and their wild‐type littermates and followed the migration and localization of these astrocytes by confocal microscopy upto 7 days after transplantation. Posttransplantation the astrocytes localized as aggregates or thin strings of many cells within the hippocampi of APdE9 and wild‐type mice and showed limited migration from the injection site. Interestingly, most of the transplanted astrocytes were found near Aβ deposits in the hippocampi of APdE9 mice. In contrast to findings in ex vivo degradation assay, confocal microscopy revealed that both adult and neonatal transplanted astrocytes internalized human Aβ immunoreactive material in vivo. These results support the role of astrocytes as active Aβ clearing cells in the CNS that may have important implications for future development of therapeutic strategies for AD. © 2007 Wiley‐Liss, Inc.
Do family caregivers perceive more difficulty when they look after patients with early onset dementia compared to those with late onset dementia?
Authors: Arai Asuna , Matsumoto Teruhisa , Ikeda Manabu , Arai Yumiko
Published: November 2007

Objective

To compare family caregiving situations for patients with early onset dementia (EOD) and late onset dementia (LOD), and to identify the specific problems experienced by relatives caring for EOD patients.

Methods

The participants were chosen from 92 consecutive caregiver–patient dyads, comprising co‐residing family caregivers and outpatients who fulfilled the diagnostic criteria for dementia. The patients were assessed according to cognitive function, neuropsychiatric disturbances and the severity of dementia. The caregivers completed a self‐administered questionnaire that included items on their sociodemographic status and caregiving situation. Caregiver burden was assessed by the Japanese version of the Zarit Burden Interview.

Results

In total, 68 dyads were eligible for the analysis, 14 of which included patients with EOD and 54 of which included patients with LOD. There were no significant differences between the two groups in terms of patient clinical features, duration of caregiving, number of hours during which caregivers were relieved per day or number of hours of caregiving per day. No significant associations were detected between the type of dementia and caregiver characteristics (such as health status) or caregiver burden, even after adjusting for confounding variables. However, the caregivers of EOD patients had greater perceived difficulties due to patient behavioural disturbances than did the caregivers of LOD patients.

Conclusions

Our findings demonstrated that additional resources, such as care services, should be provided for sufferers of EOD, in order to allow family caregivers to cope with difficulties associated with patient behavioural problems. Copyright © 2007 John Wiley & Sons, Ltd.
Out‐of‐pocket payment for medical care under Taiwan's National Health Insurance system
Authors: Chi Chunhuei , Lee Jwo‐Leun , Tsai Shu‐Ling , Chen Wen‐Yi
Published: November 2007

The objective of this study is to estimate the amount of and factors associated with out‐of‐pocket (OOP) payment for medical care under Taiwan's National Health Insurance (NHI) program. This research used two methods to collect original data. The first method consisted of using a sample household survey and household diary records to collect data on OOP payment prospectively over a two‐month period from a random sample of 600 households in central Taiwan. Using the individual as the unit of analysis, we obtained a total of 1062 sample subjects. To ascertain the quality and accuracy of survey data, the claim records of the bureau of NHI were merged with the survey data. These data were analyzed by a two‐part model, with a probit model for use of health care and an ordinary least‐squares model for OOP payments. Results of this research indicate that on average an individual's annual OOP payment for medical care was € 247, which is substantial, compared with the average € 144 for per capita NHI earmarked tax. Finally, results of model estimation indicate that supplemental health insurance and household income were positively associated with any use of health care, while household income was also positively associated with OOP payment for health care. Copyright © 2007 John Wiley & Sons, Ltd.
Equity, governance and financing after health care reform: lessons from Mexico
Authors: Arredondo Armando , Orozco Emanuel
Published: November 2007

To determine, from the perspective of providers, community leaders and users of health services, equity, governance and health financing outcomes of the Mexican health system reform.Cross‐sectional study oriented towards the qualitative analysis of financing, governance and equity indicators for the uninsured population. Taking into account feasibility, as well as political and technical criteria, six Mexican states were selected as study populations and a qualitative research was conducted during 2004–2006. Two hundred and forty in‐depth interviews were applied, in all selected states, to 60 decision‐makers, including medical and administrative personnel; 60 service providers at health centres; 60 representatives of civil organizations, including municipal representatives and, finally, 60 members of health committees and users of services at second and first levels of care units. The analysis of interviews was performed using ATLAS‐Ti software. An outcome mapping of health reform was developed.For political actors, Mexican health system reform has not modified dependence on the central level; ignorance about reform strategies and lack of participation in the search for financial resources to finance health systems were evidenced. Also, in all states under study, community leaders and users of services reported the need to improve an effective accountability system at both municipal and state levels. Health strategies for equity, governance and financing do not have adequate mechanisms to promote participation from all social actors. Improving this situation is a very important goal in the Mexican health democratization process, in the context of health care reform. There are relevant positive and negative effects of the reform on equity, governance and financing in health. Special emphasis is placed on the analysis of lessons learned in Mexico and the usefulness of the main strengths and weaknesses, as relevant evidences for other middle‐income countries which are designing, implementing and evaluating reform strategies in order to achieve equity in resource allocation, good levels of governance and a greater financial protection in health. Copyright © 2007 John Wiley & Sons, Ltd.
Exchange rates and product variety
Authors: Simbanegavi Witness
Published: November 2007

We study the role of exchange rate variability in the firm's choice of whether to offer one or two varieties. We show that variability induces the firm to vertically segment markets (offer two varieties). This happens because variability in the exchange rate affects income dispersion and hence the firm's incentives to extract consumer surplus. To better extract surplus, the firm offers two price‐quality menus, a high‐quality variant geared for top‐end surplus extraction and a low‐quality variant to address market coverage concerns. Copyright © 2007 John Wiley & Sons, Ltd.
Validity of methyl mercury hair analysis: mercury monitoring in human scalp/nude mouse model
Authors: Zareba Grazyna , Cernichiari Elsa , Goldsmith Lowell A. , Clarkson Thomas W.
Published: November 2007

Objective. The grafting of human scalp hair was used as a new application of this method to explore methyl mercury incorporation into human hair and to validate this model for mercury monitoring in hair.

Methods. Human scalp grafts were transplanted to athymic BALB/c nude mice. The animals were exposed to methyl mercury either as a single dose i.p. or continuously for 4 months, using ALZET osmotic pumps. The mercury concentration in hair was determined using x‐ray fluorescence (XRF) spectrometry by segmental (2 mm) analysis of a single strand, and tissue concentrations were measured by cold vapor atomic absorption analysis.

Results. Human scalp hair grown in nude mice showed long‐term persistence of human features including the expression of histocompatibility antigens (KAB 3, W 6/32, SF 1‐1.1.1) and normal hair morphometry. The disposition of methyl mercury in nude mice followed a one‐compartment model with a whole body elimination half‐life of 6.7 days (elimination constant, k = 0.1/day). Autoradiographic studies revealed that methyl mercury was rapidly incorporated into areas of the hair follicle undergoing active keratinization. Methyl mercury concentrations in human hair transplanted onto nude mice were two orders of magnitude higher than in blood and attained a mean hair: blood ratio of 217 : 1, similar to ratios reported only in human studies.

Conclusions. This study demonstrated that human hair grown on nude mice can record the level of exposure to methyl mercury and can serve as a valuable research tool to study mercury incorporation into human hair. Copyright © 2007 John Wiley & Sons, Ltd.
Dose‐dependent differential upregulation of CCN1/Cyr61 and CCN3/NOV by the gap junction protein Connexin43 in glioma cells
Authors: Sin Wun Chey , Bechberger John F. , Rushlow Walter J. , Naus Christian C.
Published: November 2007

Gap junctions form channels that allow exchange of materials between cells and are composed of transmembrane protein subunits called connexins. While connexins are believed to mediate cellular signaling by permitting intercellular communication to occur, there is also increasing evidence that suggest connexins may mediate growth control via a junction‐independent mechanism. Connexin43 (Cx43) is the most abundant gap junction protein found in astrocytes, and gliomas exhibit reduced Cx43 expression. We have previously observed that restoration of Cx43 levels in glioma cells led to increased expression of CCN3 (NOV) proteins. We now report that overexpression of Cx43 in C6‐glioma cells (C6‐Cx43) also upregulates the expression of CCN1 (Cyr61). Both CCN1 and CCN3 belong to the Cyr61/Connective tissue growth factor/Nephroblastoma‐overexpressed (CCN) family of secretory proteins. The CCN proteins are tightly associated with the extracellular matrix and have important roles in cell proliferation and migration. CCN1 promotes growth in glioma cells, as shown by the increased proliferation rate of CCN1‐overexpressing C6 cells. In addition to its effect on cell growth, CCN1 also increased the motility of glioma cells in the presence of extracellular substrates such as fibronectin. Gliomas expressing high levels of Cx43 preferentially upregulated CCN3 which resulted in reduced growth rate. CCN3 could also be observed in Cx43 gap junction plaques in confluent C6‐Cx43H culture at the stationary phase of their growth. Our results suggest that the dissimilar growth characteristics between high and low Cx43 expressors may be due to differential regulation of CCN3 by varying levels of Cx43. J. Cell. Biochem. 103: 1772–1782, 2007. © 2007 Wiley‐Liss, Inc.
N‐linked glycosylation of the liver cancer biomarker GP73
Authors: Norton Pamela A. , Comunale Mary Ann , Krakover Jonathan , Rodemich Lucy , Pirog Natalie , D'Amelio Anthony , Philip Ramila , Mehta Anand S. , Block Timothy M.
Published: November 2007

The association between elevated circulating levels of GP73 (and fucosylated GP73 in particular) and hepatocellular carcinoma suggests that a thorough analysis of the extent of GP73 glycosylation is warranted. Detailed analysis of the glycosylation patterns of such low abundance proteins are hampered by technical difficulties. Using conventional lectin affinity chromatography, we have established that three quarters of the GP73 secreted from a cell line derived from HCC is fucosylated. Using mass spectrometry, we have established that at least two of three potential sites of N‐linked glycosylation are occupied on most molecules of GP73 secreted from cultured hepatoma cells. Furthermore, the oligosaccharides added to recombinant GP73 resemble those present in the bulk of secreted protein, mostly bi‐antennary with core fucose, with a smaller fraction of tri‐ and tetra‐antennary structures. The frequency of fucosylation observed on the recombinant protein agrees well with the pattern of lectin binding of the endogenous secreted protein. Finally, we have developed a method to interrogate the glycans added to either the near full length protein or at a particular sequon, providing proof of concept that a small peptide embedded in a heterologous context can preserve both fucosylation and a high level of branching of oligosaccharides added. J. Cell. Biochem. 104: 136–149, 2008. © 2007 Wiley‐Liss, Inc.
Regulation of apoptosis by modified naringenin derivatives in human colorectal carcinoma RKO cells
Authors: Lee Eung‐Ryoung , Kang Yong‐Jin , Kim Hyun‐Jeong , Choi Hye‐Yeon , Kang Geun‐Ho , Kim Jung‐Hyun , Kim Bong‐Woo , Jeong Hyo‐Soon , Park Yong‐Sun , Cho Ssang‐Goo
Published: November 2007

Flavonoids are micronutrients that are widely detected in foods of plant origin and have been ascribed pharmacological properties. Several biological functions of flavonoids have been thus far identified, whereas there currently exists a lack of evidence to support the relationship between the structure‐activity relationship and apoptosis‐inducing activity. In an attempt to determine the importance of the OH group or substitution of the 5‐ or 7‐carbon in the diphenylpropane skeleton of flavonoids, we selected 14 different flavonoids with different structures, particularly with regard to the 5‐ or 7‐carbon, and found that naringenin treatment caused a slight decrease in the cell viability of the human colorectal carcinoma RKO cells. Next, in order to characterize the effects of specific substitutions of the 7‐carbon of naringenin on apoptosis‐regulatory activities, and in an attempt to develop anti‐proliferative flavonoid derivatives that would be more effective against colon cancer, we originally synthesized several modified naringenin derivatives (MNDs) including 7‐O‐benzyl naringenin (KUF‐1) and 7‐O‐(m‐metoxybenzyl) naringenin (KUF‐2). Treatment with KUF‐1 or KUF‐2 resulted in significant apoptosis‐inducing effects concomitant with losses in mitochondrial membrane potential, caspase activation, intracellular ROS production, and sustained ERK activation. Our data show that KUF‐1 or KUF‐2 regulate the apoptosis of RKO cells via intracellular ROS production coupled with the concomitant activation of the ERK signaling pathway, thereby implying that hydroxylation or substitution at C7 is critical for the apoptosis‐inducing activity of flavonoids. J. Cell. Biochem. 104: 259–273, 2008. © 2007 Wiley‐Liss, Inc.
Effect of growth hormone on in vitro osteogenesis and gene expression of human osteoblastic cells is donor‐age‐dependent
Authors: Crippa Grasiele E. , Beloti Marcio M. , Cardoso Cristina R. , Silva João S. , Rosa Adalberto L.
Published: November 2007

It has been demonstrated that the effect of GH on bone tissue is reduced with aging. In this study we tested the hypothesis that the action of GH on osteoblastic cells is donor‐age‐dependent by investigating the effect of GH on the development of osteoblastic phenotype in cultures of cells from adolescents (13–16 years old), young adults (18–35 years old), and adults (36–49 years old). Osteoblastic cells derived from human alveolar bone were cultured with or without GH for periods of up to 21 days, and parameters of in vitro osteogenesis and gene expression of osteoblastic markers were evaluated. GH increased culture growth, collagen content and alkaline phosphatase (ALP) activity in cultures from adolescents and young adults, whereas non‐significant effect was observed in cultures from adults. While GH significantly increased the bone‐like formation in cultures from adolescents, a slightly effect was observed in cultures from young adults and no alteration was detected in cultures from adults. Results from real‐time PCR demonstrated that GH upregulated ALP, osteocalcin, type I collagen, and Cbfa1 mRNA levels in cultures from adolescents. In addition, cultures from young adults showed higher ALP mRNA expression and the expression of all evaluated genes was not affected by GH in cultures from adults. These results indicate that the GH effect on both in vitro osteogenesis and gene expression of osteoblastic markers is donor‐age‐dependent, being more pronounced on cultures from adolescents. J. Cell. Biochem. 104: 369–376, 2008. © 2007 Wiley‐Liss, Inc.
Radiosonde temperature trends and their uncertainties over eastern China
Authors: Guo Yanjun , Thorne Peter. W. , McCarthy Mark P. , Titchner Holly A. , Huang Binxun , Zhai Panmao , Ding Yihui
Published: November 2007

Trends and uncertainty in radiosonde temperature records for six sample stations in eastern China are assessed. Results from a complex approach using metadata and a two‐phase regression (M‐TPR) to capture known and unknown metadata events respectively are compared with an ensemble of possible solutions generated by the Met Office automated homogenization system (QUARC). Independent satellite records from the Microwave Sounding Unit (MSU) record are used to validate breakpoints over the satellite era.

Differences in the treatment of metadata and the strictness of the statistical breakpoint detection methods used lead to relatively poor agreement in breakpoint identification. Agreement in long‐term (1958–2003) trends in the homogenized data was found to result from a fortuitous cancellation of large differences in the pre‐ and post‐satellite era trends between the two approaches.

A consideration of independent MSU satellite data lends some credence to the presence and calculated magnitude of many of the assigned breakpoints that were not associated with recorded metadata events, in the later part of the record. However, it also highlights that neither of the approaches is likely to be perfect at identifying breaks. Improved metadata are likely to prove vital in confirming the presence of these breaks and hence the veracity of the various homogenization approaches to data for eastern China. Copyright © 2007 Royal Meteorological Society
The patella ligament insertion angle influences quadriceps usage during walking of anterior cruciate ligament deficient patients
Authors: Shin Choongsoo S. , Chaudhari Ajit M. , Dyrby Chris O. , Andriacchi Thomas P.
Published: November 2007

Following ACL injury a reduction in the peak knee flexion moment during walking (thought to be created by a decrease of quadriceps contraction) has been described as an adaptation to reduce anterior tibial translation (ATT) relative to the femur. However, the amount of ATT caused by quadriceps contraction is influenced by the patellar ligament insertion angle (PLIA). The purpose of this study was to test the hypothesis that quadriceps usage during walking correlates to individual anatomical variations in the extensor mechanism as defined by PLIA. PLIA and gait were measured for ACL‐deficient knees, using subjects' contralateral knees as controls. In ACL‐deficient knees, PLIA was negatively correlated (R2 = 0.59) to peak knee flexion moment (balanced by net quadriceps moment), while no correlation was found in contralateral knees. Reduction in peak flexion moment in ACL‐deficient knees compared to their contralateral knees was distinctive in subjects with large PLIA, possibly to avoid excessive ATT. These results suggest that subject‐specific anatomic variability of knee extensor mechanism may account for the individual variability previously observed in adaptation to a quadriceps reduction strategy following ACL injury. The average (±1 SD) PLIA of ACL‐deficient knees (21.1 ± 3.4°) was less than the average PLIA of contralateral knees (23.9 ± 3.1°). This altered equilibrium position of the tibiofemoral joint associated with reduced PLIA and adaptations of gait patterns following ACL injury may be associated with degenerative changes in the articular cartilage. In the future, individually tailored treatment and rehabilitation considering individuals' specific extensor anatomy may improve clinical outcomes. © 2007 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 25:1643–1650, 2007
Adsorption of 4,4′‐thiobisbenzenethiol on silver surfaces: surface‐enhanced Raman scattering study
Authors: Wang Yuling , Chen Hongjun , Dong Shaojun , Wang Erkang
Published: November 2007

Adsorption of 4,4′‐thiobisbenzenethiol (4,4′‐TBBT) on a colloidal silver surface and a roughened silver electrode surface was investigated by means of surface‐enhanced Raman scattering (SERS) for the first time, which indicates that 4,4′‐TBBT is chemisorbed on the colloidal silver surface as dithiolates by losing two H‐atoms of the SH bond, while as monothiolates on the roughened silver electrode. The different orientations of the molecules on both silver surfaces indicate the different adsorption behaviors of 4,4′‐TBBT in the two systems. It is inferred from the SERS signal that the two aromatic rings in 4,4′‐TBBT molecule are parallel to the colloidal silver surface as seen from the disappearance of νCH band (3054 cm−1), which is a vibrational mode to be used to determine the orientation of a molecule on metals according to the surface selection rule, while on the roughened silver electrode surface they are tilted to the surface as seen from the enhanced signal of νCH. The orientation of the C‐S bond is tilted with respect to the silver surface in both cases as inferred from the strong enhancement of the νCS. SERS spectra of 4,4′‐TBBT on the roughened silver electrode with different applied potentials reveal that the enhancement of 4,4′‐TBBT on the roughened silver electrode surface may be related to the chemical mechanism (CM). More importantly, the adsorption of 4,4′‐TBBT on the silver electrode is expected to be useful to covalently adsorb metal nanoparticles through the free SH bond to form two‐ or three‐ dimensional nanostructures. Copyright © 2007 John Wiley & Sons, Ltd.
MREI‐model calculations of Raman‐active modes in layered mixed crystals TiS2−xSex(0≤x≤2)
Authors: Chanchal  , Garg A. K.
Published: November 2007

A modified random‐element isodisplacement model has been developed and used to calculate the concentration dependence of the wavenumbers of Raman‐active modes in mixed crystal system, TiS2−xSex(0≤x≤2). Earlier theoretical work, based on the Jaswal model, predicted a phase transition in this system on cooling up to 125 K temperature for the composition x ≥ 1.2. But recently reported resistivity measurements did not find the existence of any phase transition for a composition x < 1.4 on cooling. Our calculations show these findings and give remarkably better fitting to Raman data. The estimated values of the force constants are found to lie generally in the range 105–106 amu cm−2. Copyright © 2007 John Wiley & Sons, Ltd.
A rapid, non‐destructive method of detecting diagenetic alteration in fossil bone using Raman spectroscopy
Authors: Thomas Daniel B. , Fordyce R. Ewan , Frew Russell D. , Gordon Keith C.
Published: November 2007

Biogenic isotopes of analytical interest may be stripped from bone during burial, reducing the utility of fossil specimens for paleobiological and paleoenvironmental reconstruction. Denudation of the bone lattice coupled with the addition of exotic ions can influence the Raman spectra of fossil bone. Modern bone samples (n = 43) were used to establish an unaltered bone standard, and a suite of synthetic apatite samples were produced to simulate the addition of various ions into the bone mineral lattice. Diagenetic alteration produces distinct spectral characters, providing qualifications for major ionic substitution, ionic heterogeneity, the abundance of structural carbonate, the presence of calcium carbonate and the presence of luminescent ions. Spectral indicators (proxies) provide the means of rapidly and nondestructively evaluating the degree of alteration and thus the analytical utility of fossil bones, potentially avoiding exhaustive and destructive analysis on finite material. Copyright © 2007 John Wiley & Sons, Ltd.
Improved thermal stability of perfluoropolyalkylethers (PFPAEs)
Authors: Howell Jon L. , Friesen Chadron M. , Shtarov Alexander B. , Thrasher Joseph S. , Waterfeld Alfred , Pérez Erik W. , Sullivan Jonathan F.
Published: November 2007

End‐group modification of poly(hexafluoropropylene oxide), a perfluoropolyalkylether (PFPAE) shows a dramatic increase in thermal stability under conditions designed to mimic a severe tribological environment. The end‐group modifications in this study include perfluoroethyl (ethyl‐F, EA‐F), n‐perfluoropropyl (n‐propyl‐F, NPA‐F), isoperfluoropropyl (isopropyl‐F, IPA‐F) and n‐perfluorohexyl (n‐hexyl‐F, NHA‐F). Amorphous aluminum fluoride (AlF3) was charged with a monodispersion of a modified PFPAE and was evaluated for thermal stability (200–270 +/− 1°C). The percent degradation of each type of end‐group has been measured by gas chromatography/mass spectrometry, and the mechanisms of decomposition have been reported. Copyright © 2007 John Wiley & Sons, Ltd.
Authentication of Radix Aucklandiae and its substitutes by GC‐MS and hierarchical clustering analysis
Authors: Shum Ka‐Chiu , Chen Feng , Li Song‐Lin , Wang Jun , But Paul Pui‐Hay , Shaw Pang‐Chui
Published: November 2007

Radix Aucklandiae (Muxiang in Chinese), the dried root of Aucklandia lappa, is used as a medicinal material for digestive system disorders in traditional Chinese medicine for centuries. Owing to the similarity of morphologies and trade names, Radix Vladimiriae (Chuan‐Muxiang), the roots of Vladimiria souliei and V. souliei var. cinerea, and Radix Inulae (Tu‐Muxiang), the roots of Inula helenium and Inula racemosa, as well as the renal toxic aristolochic acid containing Radix Aristolochiae (Qing‐Muxiang), the roots of Aristolochia debilis and Aristolochia contorta, are often used confusedly as the substitutes of Radix Aucklandiae. In order to ensure the effective and safe utility of Radix Aucklandiae, a GC‐MS method was developed to generate the chemical profiles of essential oils of Radix Aucklandiae and its substitutes. In addition, hierarchical clustering analysis was used to compare the similarities of these chemical profiles. It was found that all the samples of A. lappa have similar chemical profiles and were clustered into one group, while the samples of Radix Vladimiriae, Radix Inulae, and Radix Aristolochiae were clustered into their own independent groups, respectively, suggesting that together with hierarchical clustering analysis, chemical profiles of essential oils generated by GC‐MS could objectively discriminate Radix Aucklandiae from its common substitutes.