bluuebunny/crossref_metadata_2025 huggingface dataset:
CagA+ Helicobacter pylori infection and gastric cancer risk in the EPIC‐EURGAST study
Authors: Palli Domenico , Masala Giovanna , Del Giudice Giuseppe , Plebani Mario , Basso Daniela , Berti Duccio , E. Numans Mattijs , Ceroti Marco , Peeters Petra H.M. , de Mesquita H. Bas Bueno , Buchner Frederike L. , Clavel‐Chapelon Francoise , Boutron‐Ruault Marie‐Christine , Krogh Vittorio , Saieva Calogero , Vineis Paolo , Panico Salvatore , Tumino Rosario , Nyrén Olof , Simán Henrik , Berglund Goran , Hallmans Goran , Sanchez Maria‐Jose , Larrãnaga Nerea , Barricarte Aurelio , Navarro Carmen , Quiros Jose R. , Key Tim , Allen Naomi , Bingham Sheila , Khaw Kay Tee , Boeing Heiner , Weikert Cornelia , Linseisen Jakob , Nagel Gabriele , Overvad Kim , Thomsen Reimar W. , Tjonneland Anne , Olsen Anja , Trichoupoulou Antonia , Trichopoulos Dimitrios , Arvaniti Athina , Pera Guillem , Kaaks Rudolf , Jenab Mazda , Ferrari Pietro , Nesi Gabriella , Carneiro Fatima , Riboli Elio , Gonzalez Carlos A.
Published: November 2006

Helicobacter pylori (H. pylori), atrophic gastritis, dietary and life‐style factors have been associated with gastric cancer (GC). These factors have been evaluated in a large case–control study nested in the European Prospective Investigation into Cancer and Nutrition carried out in 9 countries, including the Mediterranean area. Participants, enrolled in 1992–1998, provided life‐style and dietary information and a blood sample (360,000; mean follow‐up: 6.1 years). For 233 GC cases diagnosed after enrolment and their 910 controls individually‐matched by center, gender, age and blood donation date H. pylori antibodies (antilysate and antiCagA) and plasma Pepsinogen A (PGA) were measured by ELISA methods. Severe chronic atrophic gastritis (SCAG) was defined as PGA circulating levels <22 μg/l. Overall, in a conditional logistic regression analysis adjusted for education, smoke, weight and consumption of total vegetables, fruit, red and preserved meat, H. pylori seropositivity was associated with GC risk. Subjects showing only antibodies anti‐H. pylori lysate, however, were not at increased risk, while those with antiCagA antibodies had a 3.4‐fold increased risk. Overall, the odds ratio associated with SCAG was 3.3 (95% CI 2.2–5.2). According to site, the risk of noncardia GC associated with CagA seropositivity showed a further increase (OR 6.5; 95% CI 3.3–12.6); on the other hand, a ten‐fold increased risk of cardia GC was associated with SCAG (OR 11.0; 95% CI 3.0–40.9). These results support the causal relationship between H. pylori CagA+ strains infection, and GC in these European populations even after taking into account dietary habits. This association was limited to distal GC, while serologically defined SCAG was strongly associated with cardia GC, thus suggesting a divergent risk pattern for these 2 sites. © 2006 Wiley‐Liss, Inc.
MTHFR C677T and colorectal cancer risk: A meta‐analysis of 25 populations
Authors: Hubner Richard A. , Houlston Richard S.
Published: November 2006

The common functional methylenetetrahydrofolate reductase (MTHFR) C677T polymorphism may influence the risk of colorectal cancer (CRC), but data from published studies with individually low statistical power are conflicting. To clarify the role of MTHFR C677T genotype in CRC, we considered all available studies in a meta‐analysis. Studies reporting on MTHFR C677T genotype and CRC were searched in PubMed up to April 2006. The principle prior hypothesis was that homozygosity for MTHFR 677TT would be associated with reduced risk of CRC. Data were available for 29,931 subjects, including 12,243 with CRC, from 25 independent populations. Compared to the homozygous CC genotype, the MTHFR 677TT genotype was associated with a reduced risk of CRC (odds ratio (OR): 0.83; 95% confidence interval (CI): 0.75–0.93; p = 0.001). There was some heterogeneity among the results of individual studies, but this was not statistically significant (heterogeneity p = 0.12; I2 = 25.8%). Heterozygosity for MTHFR 677 did not influence CRC risk (OR: 0.99; 95% CI: 0.94–1.04). These findings indicate that individuals homozygous for the MTHFR 677TT genotype are at moderately reduced risk of CRC, and support the proposal that common genetic variation in the MTHFR gene contributes to CRC susceptibility, probably accounting for at least 9% of the total incidence. © 2006 Wiley‐Liss, Inc.
Prediction of metastasis from low‐malignant breast cancer by gene expression profiling
Authors: Thomassen Mads , Tan Qihua , Eiriksdottir Freyja , Bak Martin , Cold Søren , Kruse Torben A.
Published: November 2006

Promising results for prediction of outcome in breast cancer have been obtained by genome wide gene expression profiling. Some studies have suggested that an extensive overtreatment of breast cancer patients might be reduced by risk assessment with gene expression profiling. A patient group hardly examined in these studies is the low‐risk patients for whom outcome is very difficult to predict with currently used methods. These patients do not receive adjuvant treatment according to the guidelines of the Danish Breast Cancer Cooperative Group (DBCG). In this study, 26 tumors from low‐risk patients were examined with gene expression profiling. An intermediate risk group of 34 low‐malignant T2 tumors that fulfilled all other low‐risk criteria than tumor size was included to increase statistical power. A 32‐gene classifier, HUMAC32, was identified and it predicted metastases with 80% sensitivity and 77% specificity. The classifier was also validated in an independent group of high‐risk tumors resulting in comparable performance of HUMAC32 and a 70‐gene classifier developed for this group. Furthermore, the 70‐gene signature was tested in our low‐ and intermediate‐risk samples. The results demonstrated high cross‐platform consistency of the classifiers. Higher performance of HUMAC32 was demonstrated among the low‐malignant cancers compared with the 70‐gene classifier. This suggests that although the metastatic potential to some extend is determined by the same genes in groups of tumors with different characteristics and risk, expression‐based classification specifically developed in low‐risk patients have higher predictive power in this group. © 2006 Wiley‐Liss, Inc.
Dietary zinc, copper and selenium, and risk of lung cancer
Authors: Mahabir Somdat , Spitz Margaret R. , Barrera Stephanie L. , Beaver Shao Hua , Etzel Carol , Forman Michele R.
Published: November 2006

Zinc, copper and selenium are important cofactors for several enzymes that play a role in maintaining DNA integrity. However, limited epidemiologic research on these dietary trace metals and lung cancer risk is available. In an ongoing study of 1,676 incident lung cancer cases and 1,676 matched healthy controls, we studied the associations between dietary zinc, copper and selenium and lung cancer risk. Using multiple logistic regression analysis, the odds ratios (OR) and 95% confidence intervals (CI) of lung cancer for all subjects by increasing quartiles of dietary zinc intake were 1.0, 0.80 (0.65–0.99), 0.64 (0.51–0.81), 0.57 (0.42–0.75), respectively (p trend = 0.0004); similar results were found for men. For dietary copper, the ORs and 95% CI for all subjects were 1.0, 0.59 (0.49–0.73), 0.51 (0.41–0.64), 0.34 (0.26–0.45), respectively (p trend < 0.0001); similar reductions in risk and trend were observed by gender. Dietary selenium intake was not associated with risk, except for a significant inverse trend (p = 0.04) in men. Protective trends (p < 0.05) against lung cancer with increased dietary zinc intake were also found for all ages, BMI > 25, current smokers, pack‐years ≤30, light drinkers and participants without emphysema. Increased dietary copper intake was associated with protective trends (p < 0.05) across all ages, BMI, smoking and vitamin/mineral supplement categories, pack‐years ≤30 and 30.1–51.75 and participants without emphysema. Our results suggest that dietary zinc and copper intakes are associated with reduced risk of lung cancer. Given the known limitations of case–control studies, these findings must be interpreted with caution and warrant further investigation. © 2006 Wiley‐Liss, Inc.
The association of use of sunbeds with cutaneous malignant melanoma and other skin cancers: A systematic review
Authors:   The International Agency for Research on Cancer Working Group on artificial ultraviolet (UV) light and skin cancer
Published: November 2006

Exposure to solar ultraviolet (UV) radiation is a known cause of skin cancer. Sunbed use represents an increasingly frequent source of artificial UV exposure in light‐skinned populations. To assess the available evidence of the association between sunbed use and cutaneous malignant melanoma (melanoma) and other skin cancers, a systematic review of the literature till March 2006 on epidemiological and biological studies on sunbed use was performed in Pubmed, ISI Web of Science, Embase, Pascal, Cochrane library, Lilacs and Medcarib. Search for keywords in the title and in the abstract was done systematically and supplemented by manual searches. Only case–control, cohort or cross‐sectional studies were selected. Data were abstracted by means of a standardized data‐collection protocol. Based on 19 informative studies, ever‐use of sunbeds was positively associated with melanoma (summary relative risk, 1.15; 95% CI, 1.00–1.31), although there was no consistent evidence of a dose–response relationship. First exposure to sunbeds before 35 years of age significantly increased the risk of melanoma, based on 7 informative studies (summary relative risk, 1.75; 95% CI, 1.35–2.26). The summary relative risk of 3 studies of squamous cell carcinoma showed an increased risk. For basal cell carcinoma, the studies did not support an association. The evidence does not support a protective effect of the use of sunbeds against damage to the skin from subsequent sun exposure. Young adults should be discouraged from using indoor tanning equipment and restricted access to sunbeds by minors should be strongly considered. © 2006 Wiley‐Liss, Inc.
The Engel curve for alcohol and the rank of demand systems
Authors: Unayama Takashi
Published: November 2006

This paper shows that the quadratic shape of the Engel curve for alcohol is induced by preference heterogeneity between drinkers and abstainers in a Japanese data set. With controlling the heterogeneity, it is shown that the Engel curve for alcohol slopes monotonically downwards for drinkers, and that the probability of being a drinker is an increasing function of total expenditure. These two relationships generate a quadratic shape for the Engel curve for alcohol. Other goods in this data set appear to have nearly linear Engel curves, so if the alcohol Engel curve for drinkers is also linear, then after controlling for this preference heterogeneity the rank of this demand system would be two. Copyright © 2006 John Wiley & Sons, Ltd.
Convergence of productivity: a comment
Authors: Wang Zijun
Published: November 2006

We find that an important programming error was made by Hobijn and Franses (2000) in conducting multivariate stationarity tests. The empirical results in their paper are subject to errors. Other studies that have used the coded algorithm of Hobijn and Franses are likely to suffer the same problem. Copyright © 2006 John Wiley & Sons, Ltd.
Plasma‐controlled nanocrystallinity and phase composition of TiO2: A smart way to enhance biomimetic response
Authors: Zhou Wei , Zhong Xiaoxia , Wu Xiaochen , Yuan Luqi , Shu Qiwei , Xia Yuxing , Ostrikov Kostya (Ken)
Published: November 2006

This contribution sheds light on the role of crystal size and phase composition in inducing biomimetic apatite growth on the surface of nanostructured titania films synthesized by reactive magnetron sputtering of Ti targets in Ar+O2 plasmas. Unlike most existing techniques, this method enables one to deposit highly crystalline titania films with a wide range of phase composition and nanocrystal size, without any substrate heating or postannealing. Moreover, by using this dry plasma‐based method one can avoid surface hydroxylation at the deposition stage, almost inevitable in wet chemical processes. Results of this work show that high phase purity and optimum crystal size appear to be the essential requirement for efficient apatite formation on magnetron plasma‐fabricated bioactive titania coatings. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res, 2007
Mechanical stimulation induces morphological and phenotypic changes in bone marrow‐derived progenitor cells within a three‐dimensional fibrin matrix
Authors: Nieponice Alejandro , Maul Timothy M. , Cumer Joy M. , Soletti Lorenzo , Vorp David A.
Published: November 2006

One of the major limitations in tissue engineering is cell sourcing. Multipotent progenitor cells appear to have many promising features for that purpose. Mechanical stimulation is known to play an important role in determining cell phenotype. The aim of this work was to investigate the effects of cyclic stretch on rat bone marrow derived progenitor cell (BMPC) morphology and smooth muscle‐directed differentiation within a three‐dimensional fibrin matrix. BMPCs were suspended in a fibrin gel, pipetted into the trough of Flexcell™ Tissue‐Train™ plates, and stimulated with 10% longitudinal cyclic stretch at 1 Hz for 6 days. Unconstrained (stress‐ and strain‐free) and static anchored (constrained but not stretched) samples were used as controls. Stress filament area per cell was increased in the stretched samples compared to static anchored and free‐float controls. Cells in the free float controls were randomly aligned, while they aligned parallel to the direction of the stress or strain in the other groups. Immunofluorescence suggested an increased expression of smooth muscle markers (smooth muscle α actin and h1‐calponin) in both stretched and constrained control samples, but not in unconstrained controls. Qualitative assessment suggested that collagen production was increased in both mechanically stimulated samples. Proliferation was inhibited in stretched samples compared to the constrained controls. This work suggests an ability of rat BMPCs to differentiate toward a smooth‐muscle‐cell‐like lineage when exposed to biomechanical stimulation in a three‐dimensional model. The observation that the constrained samples induced changes in BMPCs suggests that stress alone may be stimulatory, but addition of cyclic stretch appears to augment the responses. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res, 2007
Influence of gradual introduction of hydrophobic groups (stearic acid) in denatured atelocollagen on fibroblasts behavior in vitro
Authors: Forest P.O. , Karoum R. , Gagnieu C.H.
Published: November 2006

To prepare new biocompatible hydrophobic collagen films for medical devices, innovative collagen derivatives were synthesized by reaction of the lysyl amino groups of the α‐chains with activated stearic acid. Different collagens having different substitution degrees were obtained and used to prepare films crosslinked with oxidized glycogen. Their physicochemical surface properties were evaluated, and in vitro assays were performed to analyze the behavior of fibroblasts in contact with the materials. The assays were performed with cells in adhesion and growth phases. The hydrophobic properties increased with the number of stearic acid introduced in the collagen but only in the range of 1–12 stearic acids per molecule. For higher modifications a decrease of hydrophoby was observed. All the films induced a decrease of cells growth and adhesion but without cytotoxicity. These effects were more pronounced for the collagen containing about eight stearic acid residues. Cells behavior on modified collagens films seems to be related to the chemical groups exposed on the surface of the films. Indeed, the surface chemistry directly influences the adsorption of adhesion proteins and modulates their conformation therefore modifying the cell adhesion. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res, 2007
Promoting systems change in the health care response to domestic violence
Authors: Allen Nicole E. , Lehrner Amy , Mattison Erica , Miles Teresa , Russell Angela
Published: November 2006

Community psychologists have a long‐standing interest in promoting systems change to improve the lives of individuals and communities. To more fully illuminate a multilevel model of those factors involved in the promotion of systems change, the current study examined individual‐ and organizational‐level characteristics related to health care providers' implementation of a desired reform in the community response to intimate partner violence, namely, universal screening practices. Efforts to reform the health care system's response to domestic violence prove to be difficult. The current study surveyed 209 providers across 12 health care settings to examine those factors related to reform implementation. Findings indicate that individual characteristics (perceived capacity to screen and positive beliefs about screening) and the presence of an organizational climate for implementation (e.g., consequences for implementation or failure to implement, resources to support implementation, policies and procedures consistent with desired practices) affect the extent to which health care providers engage in routine screening practices. The implications of these findings for promoting systems change, in general, and the health care system's response to domestic violence, in particular, are discussed. © 2007 Wiley Periodicals, Inc.
Development of the terminally differentiated state sensitizes epiphyseal chondrocytes to apoptosis through caspase‐3 activation
Authors: Pucci Bruna , Adams Christopher S. , Fertala Jolanta , Snyder Bradley C. , Mansfield Kyle D. , Tafani Marco , Freeman Theresa , Shapiro Irving M.
Published: November 2006

The maturation of epiphyseal chondrocytes is accompanied by dramatic changes in energy metabolism and shifts in proteins concerned with the induction of apoptosis. We evaluated the role of mitochondria in this process by evaluating the membrane potential (Δψm) of chondrocytes of embryonic tibia and the epiphyseal growth plate. We observed that there was a maturation‐dependent change in fluorescence, indicating a fall in the Δψm. The level of mitochondrial Bcl‐2 was decreased during maturation, while in the same time period there was an obvious increase in Bax levels in the mitochondrial fraction of the terminally differentiated chondrocytes. BclxL, another anti‐apoptotic protein, was also robustly expressed in the mitochondrial fraction, but its expression was not dependent on the maturation status of the chondrocytes. We found that caspase‐3 was present throughout the growth plate and in hypertrophic cells in culture. We blocked caspase‐3 activity and found that alkaline phosphatase staining and mineral formation was decreased, and the cells had lost their characteristic shape. Moreover, we noted that the undifferentiated cells were insensitive to elevated concentrations of inorganic phosphate (Pi). It is concluded that during hypertrophy, the change in membrane potential, the increased binding of a pro‐apoptotic protein to mitochondria, and the activation of caspase‐3 serve to prime cells for apoptosis. Only when the terminally differentiated chondrocytes are challenged with low levels of apoptogens there is activation of apoptosis. J. Cell. Physiol. 210: 609–615, 2007. © 2006 Wiley‐Liss, Inc.
Prevention of hyperthermia with silk of the oriental hornet, Vespa orientalis: A hypothesis
Authors: Plotkin Marian , Ermakov Natalya Y. , Volynchik Stanislav , Bergman David J. , Ishay Jacob S.
Published: November 2006

Wasps apparently develop normally even under extreme thermal conditions, including deserts. We deemed it worthwhile to set up an experiment wherein wasp brood combs containing a full gamut of brood ranging from eggs up to pupae and a few adults were kept in an incubator whose temperature was gradually raised to 45°C, and the response of the disparate brood to such warming was photographed via Infra Red camera. The finding of this experiment showed that for open brood (i.e., eggs, larvae at various instars, and empty cells) the temperature was close to the ambient temperature, but in the silk coated pupae, the temperature was lower than the ambient by up to 4°C. This lower temperature was retained for at least 90 min of incubation. For comparison we evaluated the relative contribution of the pupae to the phenomenon, by warming also a vacant, (i.e., a broodless and silkless comb) in parallel to a comb from which the pupae had been extricated but the silk weave retained and left behind. We found that the totally empty comb heated up under these conditions to nearly 110°C, whereas the silk‐containing vacant cells only heated up to about 40°C. These finding are discussed from two aspects, namely the importance for wasps to maintain a constant temperature throughout the pupating process, and the manner in which the silk weave contributes to such a goal. Microsc. Res. Tech., 2007. © 2006 Wiley‐Liss, Inc.
Design of microwave structures with MEFISTO‐3DNOVAand MATLABoptimization and neural network toolboxes
Authors: Chu Hong‐Son , So Poman P. M. , Hoefer Wolfgang J. R.
Published: November 2006

This paper introduces two time‐domain field‐based optimization procedures for microwave engineering. The methods are built on the foundations of MATLAB's optimization and neural network toolboxes. The first procedure makes use of a direct connection linking MATLAB's optimization toolbox with MEFISTO‐3DNOVA. In this approach the field simulator acts as an objective function server for the optimization toolbox; these two programs work cooperatively with each other to tune the structure parameters to obtain a target response. The second procedure is an indirect optimization approach that makes use of MATLAB's neural network toolbox in conjunction with MEFISTO‐3DNOVAto create a neural network model to emulate the structure of interest; the resulting neural network model is then used an objective function server in a normal MATLABoptimization process. Copyright © 2006 John Wiley & Sons, Ltd.
Semi‐analytical time‐domain low‐frequency scattering formulation for biological applications
Authors: Koh Il‐Suek , Kim Woo‐Tae , Yook Jong‐Gwan , Park Jae‐Chon
Published: November 2006

In this paper, an efficient time domain formulation is proposed for a low‐frequency scattering by a complicated inhomogeneous dielectric scatterer. The formulation is based on the Born approximation and a sampling theorem. To extend the valid region of the proposed solution, the Rayleigh scattering formulation for a small dielectric object is used to modify the Born current inside the scatterer. In order to verify the obtained formulation, scatterings by several canonical objects such as a cubic box and a sphere are compared, which are calculated by the proposed formulation and the known exact or approximate solutions of a Mie series and the Rayleigh scattering. In addition, scattering by a human head is investigated at a very low‐frequency band (< 100 Hz). For the simulation, two excitations are considered: plane wave incidence from outside the head and an artificial point source located inside the head. The head model is discretized by a 3 × 3 × 3 mm3 cubic box, which is comprised of eight types of tissue. These are blood, bone, fat, grey matter, white matter, muscle, skin and vitreous humor. Copyright © 2006 John Wiley & Sons, Ltd.
Upregulation of intracellular adhesion molecule (ICAM)‐1 and vascular cell adhesion molecule (VCAM)‐1 after unilateral nerve injury in the peripheral taste system
Authors: Cavallin Melissa Ann , McCluskey Lynnette Phillips
Published: November 2006

In the peripheral taste system, activated macrophages are recruited to both sides of the tongue after unilateral sectioning of the chorda tympani nerve (CT). Neural degeneration elicits macrophage entry in other systems by upregulating vascular adhesion molecules. We hypothesized that CT sectioning leads to a bilateral increase in intracellular adhesion molecule (ICAM)‐1 and vascular cell adhesion molecule (VCAM)‐1 expression on lingual vessels. To test this hypothesis, rats were euthanized at time points from 6 hr to 7 days post‐sectioning. Frozen sections of tongue were processed for immunohistochemical staining for ICAM‐1 and VCAM‐1. Tongue homogenates from additional rats were analyzed with ELISA. ICAM‐1 expression increases first on the denervated side of the tongue at 24 hr post‐section and then on the uninjured side at 48 hr post‐section. ICAM‐1 remains elevated through Day 7 post‐sectioning on both sides of the tongue. Dietary sodium restriction, which prevents the macrophage response to nerve sectioning, had no effect on ICAM‐1 levels. VCAM‐1+ vessels are increased on the denervated side of the tongue at 24–48 hr post‐section in control‐fed rats. However, dietary sodium restriction prevents the increase. These results indicate that vascular adhesion molecules are differentially regulated by CT sectioning. We suggest that macrophage entry, migration, and modulation of taste function are downstream of dynamic expression of adhesion molecules. © 2006 Wiley‐Liss, Inc.
Seminars: Local and regional anesthesia for thyroid surgery
Authors: Arora Nimmi , Dhar Panchali , Fahey Thomas J.
Published: November 2006

Background

Thyroid surgery is performed by a large number of surgeons with varying experience in thyroidectomy. The standard technique involves the use of general anesthesia, which provides patient comfort and virtually unlimited time to conduct the operation. Historically, thyroid surgery was conducted under local anesthesia by surgeons with significant expertise in the treatment of thyroid diseases. Over the past decade, there has been a renewed interest in the art of performing thyroidectomy under local/regional anesthesia in some specialized high volume endocrine surgery centers.

Methods

Here we review the indications and contraindications and technical considerations for performing thyroidectomy under local or regional anesthesia.

Results and Conclusion

Local and regional anesthesia is safe and well tolerated for the majority of thyroid surgery. J. Surg. Oncol. 2006;94:708–713. © 2006 Wiley‐Liss, Inc.
Nanocomposites of Polyaniline/Poly(2‐methoxyaniline‐5‐sulfonic acid)
Authors: Masdarolomoor Fatemeh , Innis Peter C. , Ashraf Syed , Kaner Richard B. , Wallace Gordon G.
Published: November 2006

Summary: Poly(2‐methoxyaniline‐5‐sulfonic acid) (PMAS) is a water‐soluble derivative of polyaniline that carries negatively charged sulfonate groups. This self‐doped conducting polymer also behaves like a polyelectrolyte that can subsequently function as a dopant in polyaniline (PAn). The chemical synthesis of PAn/PMAS is presented describing the preparation of a highly stable composite dispersion. TEM images reveal a mixture of well‐defined nanofibres and nanoparticles with diameters between 20 and 100 nm. The UV‐vis spectra of the PAn/PMAS composite in water and in alkaline media indicate that both PAn and PMAS are present in the composite. Electrochemical studies show that both of the conducting polymer components are capable of undergoing oxidation and reduction. The novel PAn/PMAS nanocomposite has enhanced electrical conductivity and stability compared to PAn/HCl nanofibres prepared under equivalent conditions, making it a promising material for applications in areas such as batteries, electronic textiles, electrochromics, and chemical sensors.

Transmission electron micrograph of a PAn/PMAS nanocomposite.

magnified image

Transmission electron micrograph of a PAn/PMAS nanocomposite.
Self‐Assembly and Dispersion of Chromogenic Molecules: A Versatile and General Approach for Self‐Assessing Polymers
Authors: Kunzelman Jill , Crenshaw Brent R. , Kinami Maki , Weder Christoph
Published: November 2006

Summary: Self‐assessing polymer blends based on poly(ethylene terephthalate glycol) or linear low‐density polyethylene and small amounts (0.5–2% w/w) of chromogenic sensor dyes are prepared and investigated. The cyano‐substituted oligo(p‐phenylene vinylene) dyes employed in the study exhibit pronounced optical absorption changes upon self‐assembly, because of charge‐transfer interactions or conformation changes. The extent of dye aggregation (and therewith the optical absorption characteristics) in these blends is significantly influenced by exposure to external stimuli. Subjecting appropriately processed samples to either temperatures above their glass transition or mechanical deformation can significantly change the extent of aggregation, which in turn leads to a color change.

Mechano‐optical response of a 1.0% w/w LLDPE/C18‐RG blend film. Pristine films are orange due to aggregated dye molecules. Deformation leads to dispersion of the dye and irreversibly changes the color to yellow.

magnified image

Mechano‐optical response of a 1.0% w/w LLDPE/C18‐RG blend film. Pristine films are orange due to aggregated dye molecules. Deformation leads to dispersion of the dye and irreversibly changes the color to yellow.
Prominent expression of metalloproteinases in early stages of ovarian tumorigenesis
Authors: Cai Kathy Qi , Yang Wan‐Lin , Capo‐chichi Callinice D. , Vanderveer Lisa , Wu Hong , Godwin Andrew K. , Xu Xiang‐Xi
Published: November 2006

The role for matrix metalloproteinases (MMPs) in tumor cells invasion and metastasis is well established, and expression of MMPs is recognized as an indication of tumor cell malignancy. Previous studies suggest that the degradation of the basement membrane is a crucial early step in epithelial transformation and ovarian tumorigenesis. Thus, MMPs may also express and exert a role in preneoplastic lesions of ovarian tissues. We investigated the expression of the major metalloproteinases, gelatinase A, 72 kDa type IV collagenase (MMP‐2), and gelatinase B, 92 kDa type IV collagenase (MMP‐9), and the presence of basement membrane in ovarian tumors and tissues from prophylactic oophorectomies using immunostaining. MMP expression was also characterized in a panel of ovarian cancer cell lines and several nontumorigenic ovarian surface epithelial primary cells by zymography, Northern, and Western blots. We found, surprisingly, that MMP‐2 and MMP‐9 are expressed more frequently in early lesions than in established carcinomas. No correlation was found between the expression of MMPs and tumor grades or stages. In preneoplastic lesions, MMP‐2 or MMP‐9 expression often associates with the absence of basement membrane and morphological alterations. MMP‐2 is often expressed in nontumorigenic ovarian surface epithelial cells but reduced or absent in cancer cells. Thus, we conclude that MMPs expression does not correlate with the malignancy of ovarian epithelial cells as generally thought. Rather, increased metalloproteinase expression is an early event in ovarian tumorigenesis and associates with the loss of epithelial basement membrane and morphological transformation. We propose that the increased MMP activity is an etiological factor for ovarian cancer risk. We found that MMPs expression does not correlate with the malignancy of ovarian epithelial cells as generally thought. Rather, increased metalloproteinase expression is an early event in ovarian tumorigenesis. The finding suggests roles of MMP in tumor initiation in addition to invasion, and may impact on the strategy for use of MMP inhibitors in cancer prevention. © 2006 Wiley‐Liss, Inc.
Heterocyclic amines: Chemistry and health
Authors: Cheng Ka‐Wing , Chen Feng , Wang Mingfu
Published: November 2006

Heterocyclic amines (HAs) occur at the ppb range in foods. Most of them demonstrate potent mutagenicity in bacteria mutagenicity test, and some of them have been classified by the International Agency for Research on Cancer as probable/possible human carcinogens. Their capability of formation even during ordinary cooking practices implies frequent exposure by the general public. Over the past 30 years, numerous studies have been stimulated aiming to alleviate human health risk associated with HAs. These studies contribute to the understanding of their formation, characterization, and quantification in foods; their mutagenesis/carcinogenesis, mechanisms of antimutagenesis by chemical or phytogenic modulators; and strategies to inhibit their formation. The chemistry of HAs, their implications in human health, factors influencing their formation, and feasible ways of suppression will be briefly reviewed. Their occurrence in trace amounts in foods necessitates continuous development and amelioration of analytical techniques. Various inhibitory strategies, ranging from modifying cooking conditions to incorporation of different modulators, have been developed. This will remain one of the foremost areas of research in the field of food chemistry and safety.
Quantitative 19F MR spectroscopy at 3 T to detect heterogeneous capecitabine metabolism in human liver
Authors: Klomp Dennis , van Laarhoven Hanneke , Scheenen Tom , Kamm Yvonne , Heerschap Arend
Published: November 2006

Chemotherapy in non‐responding cancer patients leads to unnecessary toxicity. A marker is therefore required that can predict the sensitivity of a specific tumour to chemotherapy, which would enable individualisation of therapy. 19F MR spectroscopy (19F MRS) can be used to monitor the metabolism of fluorinated drugs. The aim of this study was to develop a method for quantified localised detection of fluorinated compounds in human liver. For this purpose, sensitivity‐optimised localised 19F MRS methods at 3 T were used to detect MR signals from capecitabine, 5′DFUR, 5′DFCR and FBAL after oral intake of capecitabine. As the radio‐frequency (rf) coil is made tuneable to 19F and 1H, the same localisation method is applied to obtain 1H MR signals of water and of the 19F metabolites. In addition, T1 measurements have been performed to correct for measurement‐induced saturation effects. Finally, absolute tissue concentrations of capecitabine metabolites were obtained in vivo, which revealed a substantial spatial heterogeneity of these metabolites in human liver after chemotherapy. Copyright © 2006 John Wiley & Sons, Ltd.
A study of the representation of cracks with level sets
Authors: Duflot Marc
Published: November 2006

The level set method has been used for a few years to represent cracks in fracture mechanics simulations instead of an explicit description of the cracks faces geometry. This paper studies in detail the shape of the level set functions around a crack in two dimensions that is propagating with a sharp kink, obtained both with level set update methods found in the literature and with several innovative update methods developed by the author. A criterion based on the computation of a J integral of a virtual displacement field obtained with the values of the level set functions is proposed in order to assess the quality of these update methods. With the help of this criterion, two optimal approaches are identified, which predict an accurate evolution of the crack with smooth and consistent level set functions. These methods are then applied in three dimensions to the case of an initially penny‐shaped crack that propagates out of its plane. Copyright © 2006 John Wiley & Sons, Ltd.
Hybrid numerical scheme for time‐evolving wave fields
Authors: Lilis G. N. , Halder A. , Telukunta S. , Servetto S.
Published: November 2006

Many problems in geophysics, acoustics, elasticity theory, cancer treatment, food process control and electrodynamics involve study of wave field synthesis (WFS) in some form or another. In the present work, modelling of wave propagation phenomena is studied as a static problem, using finite element method and treating time as an additional spatial dimension. In particular, WFS problems are analysed using discrete methods. It is shown that a fully finite element‐based scheme is very natural and effective method for the solution of such problems.

Distributed WFS in the context of two‐dimensional problems is outlined and incorporation of any geometric or material non‐linearities is shown to be straightforward. This has significant implications for problems in geophysics or biological media, where material inhomogeneities are quite prevalent. Numerical results are presented for several problems referring to media with material inhomogeneities and predefined absorption profiles. The method can be extended to three‐dimensional problems involving anisotropic media properties in a relatively straightforward manner. Copyright © 2006 John Wiley & Sons, Ltd.
Use of moving distributed mass element for the dynamic analysis of a flat plate undergoing a moving distributed load
Authors: Wu Jia‐Jang
Published: November 2006

This paper presents the theory regarding a moving distributed mass element, so that the dynamic responses of a rectangular plate subjected to a moving distributed mass, with the effects of inertia force, Coriolis force and centrifugal force considered, can be easily determined. In which, the property matrices of the moving distributed mass element are derived by means of the principle of superposition and the definition of shape functions, and the overall property matrices of the entire vibrating system are determined from the combination of the last element property matrices of the moving distributed mass element and those of the plate itself. Since the property matrices of the moving distributed mass element have something to do with the instantaneous position and the distribution of the moving mass, they are time‐dependent and so are the overall property matrices of the entire vibrating system. Based on the last concept, the equations of motion for a rectangular plate subjected to a moving distributed mass are established and solved to yield the dynamic responses of the entire vibrating system. Numerical results reveal that the factors such as the contact area (between the moving distributed mass and the plate), moving‐load speed, inertia force, Coriolis force and centrifugal force affect the vibration characteristics of the plate to some degree. Copyright © 2006 John Wiley & Sons, Ltd.
Creating effective customer relationships in not‐for‐profit retailing: the Ten Thousand Villages example
Authors: Dato‐on Mary Conway , Joyce Mary , Manolis Chris
Published: November 2006

This paper examines Ten Thousand Villages (a not‐for‐profit organization with retail operations in US and Canada that pays Third World artisans fair market value for their works) in terms of its retailing and customer relationship management (CRM) strategies. The authors present an analysis of one Ten Thousand Villages retail store to assess if and how CRM might be successfully implemented. The analysis considers the use of a volunteer retail sales force and how volunteers might successfully interface with customers.

Copyright © 2006 John Wiley & Sons, Ltd.
The effect of management commitment to service quality on frontline employees' affective and performance outcomes: an empirical investigation of the New Zealand public healthcare sector
Authors: Ashill Nicholas J. , Carruthers Janet , Krisjanous Jayne
Published: November 2006

Very little attention has been given to understand the antecedents of service recovery performance in a public healthcare setting. In this study, a cross‐sectional survey investigates a model of service recovery performance. Frontline hospital employees completed a self‐administered questionnaire on how factors characterising management commitment to service quality (MCSQ) affect their service recovery efforts. The results suggest the influence of MCSQ is mediated by frontline employees' affective commitment to their hospital. The research advances understanding of frontline service recovery performance in a public healthcare setting and the findings indicate that public healthcare managers can take actions on a number of fronts to assist progress towards the achievement of frontline service recovery excellence.

Copyright © 2006 John Wiley & Sons, Ltd.
Effect of structure on solution and interfacial properties of sodium polystyrene sulfonate (NaPSS)
Authors: Sen Akhil Kumar , Roy Sandip , Juvekar Vinay A
Published: November 2006

Sodium polystyrene sulfonate (NaPSS) is synthesized by two different methods: one using free radical polymerization of sodium styrene sulfonate and another through post‐sulfonation of polystyrene. Both the solution and interfacial properties of the two polymers obtained from these two methods are different. The osmotic coefficient of free radically polymerized NaPSS is 20% higher than that of the NaPSS obtained from the post‐sulfonation method. Further, the free radically polymerized NaPSS has negligible interfacial activity at both air–water and toluene–water interfaces, as compared to post‐sulfonated NaPSS. The former type of NaPSS also adsorbs to a comparatively lesser extent at a solid–liquid interface. The enhanced hydrophobic character of post‐sulfonated NaPSS is explained on the basis of its intrinsically lower configurational entropy that results from the formation of intramolecular sulfone linkages, whereas the free radical method gives only a linear structure. Also, the intramolecular sulfone linkage will enhance the counter‐ion condensation and consequently decrease the osmotic coefficient of the post‐sulfonated sample. However, it is generally difficult to predict the exact degree of intramolecular sulfone linkage that may occur, as it depends on several factors. An attempt has been made to interpret some of the experimental data in the existing literature on NaPSS, which has mostly been prepared using the post‐sulfonation route. Copyright © 2006 Society of Chemical Industry
Temperature‐responsive characteristics of poly(N‐isopropylacrylamide) hydrogels with macroporous structure
Authors: Çaykara Tuncer , Kiper Simin , Demirel Gökhan , Demirci Serkan , Çakanyıldırım Çetin
Published: November 2006

Macroporous poly(N‐isopropylacrylamide) (PNIPA) hydrogels were synthesized by free‐radical crosslinking polymerization in aqueous solution from N‐isopropylacrylamide monomer and N,N‐methylenebis (acrylamide) crosslinker using poly(ethylene glycol) (PEG) with three different number‐average molecular weights of 300, 600 and 1000 g mol−1 as the pore‐forming agent. The influence of the molecular weight and amount of PEG pore‐forming agent on the swelling ratio and network parameters such as polymer–solvent interaction parameter (χ) and crosslinking density (νE) of the hydrogels is reported and discussed. Scanning electron micrographs reveal that the macroporous network structure of the hydrogels can be adjusted by applying different molecular weights and compositions of PEG during polymerization. At a temperature below the volume phase transition temperature, the macroporous hydrogels absorbed larger amounts of water compared to that of conventional PNIPA hydrogels, and showed higher equilibrated swelling ratios in aqueous medium. Particularly, the unique macroporous structure provides numerous water channels for water diffusion in or out of the matrix and, therefore, an improved response rate to external temperature changes during the swelling and deswelling process. These macroporous PNIPA hydrogels may be useful for potential applications in controlled release of macromolecular active agents. Copyright © 2006 Society of Chemical Industry
Esophageal stent improves ventilation in a child with a broncho‐esophageal fistula caused by Mycobacterium tuberculosis
Authors: Goussard P. , Sidler D. , Kling S. , Andronikou S. , Rossouw G. F. , Gie R. P.
Published: November 2006

The deployment of an esophageal stent to aid in the ventilation of a child who had developed an acquired broncho‐esophageal fistula caused by Mycobacterium tuberculosis (MTB) is described. The 12‐month‐old boy presented with respiratory failure requiring ventilation. The air leak via the fistula led to inadequate mechanical ventilation. The deployment of the stent resulted in successful ventilation, closure of the fistula, and eventual successful treatment. Pediatr Pulmonol. 2007; 42:93–97. © 2006 Wiley‐Liss, Inc.
Limited tendency of α‐helical residues to form disulfide bridges: a structural explanation
Authors: De Simone Alfonso , Berisio Rita , Zagari Adriana , Vitagliano Luigi
Published: November 2006

Disulfide bridges have an enormous impact on the structure of a large number of proteins and polypeptides. Understanding the structural basis that regulates their formation may be important for the design of novel peptide‐based molecules with a specific fold and stability. Here we report a statistical analysis of the relationships between secondary structure and disulfide bond formation, carried out using a large database of protein structures. Our analyses confirm the observation sporadically reported in previous investigations that cysteine residues located in α‐helices display a limited tendency to form disulfide bridges. The very low occurrence of the disulfide bond in all α‐chains compared to all β‐chains indicates that this property is also evident when proteins with different topologies are investigated. Taking advantage of the large database that endorsed the analysis on relatively rare motifs, we demonstrate that cysteine residues embedded in 310 helices present a good tendency to form disulfide bonds. This result is somewhat surprising since 310 helices are commonly assimilated into α‐helices. A plausible structural explanation for the observed data has been derived combining analyses of disulfide bond sequence separation and of the length of the different secondary structure elements. Copyright © 2006 European Peptide Society and John Wiley & Sons, Ltd.
Interactions of amphipathic carrier peptides with membrane components in relation with their ability to deliver therapeutics
Authors: Deshayes Sébastien , Morris May C. , Divita Gilles , Heitz Frédéric
Published: November 2006

To identify rules for the design of efficient CPPs that can deliver therapeutic agents such as nucleic acids (DNAs, siRNAs) or proteins and PNAs into subcellular compartments, we compared the properties of several primary and secondary amphipathic CPPs. Studies performed with lipid monolayers at the air–water interface have enabled identification of the nature of the lipid–peptide interactions and characterization of the influence of phospholipids on the ability of these peptides to penetrate into lipidic media. Penetration and compression experiments reveal that both peptides interact strongly with phospholipids, and observations on Langmuir–Blodgett transfers indicate that they can modify the lipid organization. Conformational investigations indicate that the lipid–peptide interactions govern the conformational state(s) of the peptides. On the basis of the ability of both peptides to promote ion permeation through both natural and artificial membranes, models illustrating the translocation processes have been proposed. One is based on the formation of a β‐barrel pore‐like structure while another is based on the association of helices. Copyright © 2006 European Peptide Society and John Wiley & Sons, Ltd.