bluuebunny/crossref_metadata_2025 huggingface dataset:
Information and Communications Technology in Chronic Disease Care
Authors: Cronquist Christensen Michael , Remler Dahlia
Published: April 2007

New information and communication technology (ICT) has the potential to improve care for chronic conditions, deliver better health outcomes, and reduce direct and indirect costs. However, realizing these gains necessitates new forms of care delivery, through adoption of ICT, the specific choice of ICT, and changes to existing forms of health care delivery. Realizing these new forms of delivery requires appropriate payment policies. The authors review the literatures on health care payment and ICT in chronic care and then apply theoretical economic analysis to determine how ICT alters health care payment policy recommendations. Using diabetes as an example, the authors identify and illustrate the disease and technology features that determine the optimal form of payment. Overall, ICT shifts the optimal blend of fee-for-service and capitation toward greater capitation. Carve-outs for ICT-supported preventive care enable more high-powered payment while addressing selection concerns.
Nursing Sensitive Databases
Authors: Alexander G. Rumay
Published: April 2007

The National Quality Forum uses the term “nurse-sensitive” care to describe health care quality that is influenced by nursing. Identifying this type of care requires useful data and development of measures. Establishing a case for nursing-sensitive performance measurement will facilitate a supportive climate for research and measure development. Interdisciplinary investigations will result in more adequate measures and wider acceptance of the measures in the provider community. This article summarizes existing data sources and recommendations for improving measures, data collection, and research on nurse-sensitive care.
Nursing Measures
Authors: Kosel Keith , Gelinas Lillee , Paxson Connie
Published: April 2007

With today's focus on performance measurement, pay for quality, and other data-driven initiatives in the health care industry, measurement developers and researchers interested in testing these metrics need to keep in mind the needs of those end users that will be tasked with collecting, submitting, and in many cases analyzing the information that flows from these measures. This article will highlight a number of key issues learned from the field and suggest opportunities for research into the design and deployment of these measures.
Advancing the Science in the Measurement of Health Care Quality Influenced by Nurses
Authors: Naylor Mary D.
Published: April 2007

A robust set of quality measures is essential to provide consumers with a vehicleto evaluate nurses' contributions to the care of hospitalized patients, providers, and systems with a set of nursing processes and outcomes to guide quality improvement, and insurers with indicators to reward hospitals for high quality nursing services. The processes employed by the Nursing Care Performance Measures Steering Committee convened by the National Quality Forum (NQF) in 2004 resulted in the endorsement of 15 indicators of health care quality influenced by nurses and contributed to the identification of significant gaps in measurement and priority areas for future research. This critical review of the state of the science related to health care processes and outcomes that reflect nurses' contributions to the quality of care for hospitalized patients is intended to push the boundaries in the measurement of nursing performance. Specific recommendations for future research and measure development are presented.
Specifying and Standardizing Performance Measures for Use at a National Level
Authors: Riehle Annette I. , Hanold Linda S. , Sprenger Sharon L. , Loeb Jerod M.
Published: April 2007

This article explicates a comprehensive process for identifying, specifying, testing, and implementing nationally standardized performance measures. A growing body of research ties nurse staffing to patient outcomes, reinforcing the important role of nursing in the delivery of safe, efficacious health care. The Joint Commission has developed a multistep process to identify robust sets of evidence-based measures that includes a review of the evidence, expert advisory panel guidance, use of established criteria, public input and comment, and multistage field testing before implementation. This proven approach to the establishment of performance metrics is applicable to the identification and implementation of nurse-sensitive workforce measures. These metrics can then be used by providers to support performance improvement activities by health care stakeholders to monitor nurse staffing-related issues, and by researchers to better understand the relationship between staffing effectiveness and patient safety, and the quality of health care.
Erythropoietin modulation of podocalyxin and a proposed erythroblast niche
Authors: Sathyanarayana Pradeep , Menon Madhu P. , Bogacheva Olga , Bogachev Oleg , Niss Knut , Kapelle William S. , Houde Estelle , Fang Jing , Wojchowski Don M.
Published: April 2007

Epo's erythropoietic capacity is ascribed largely to its antiapoptotic actions. In part via gene profiling of bone marrow erythroblasts, Epo is now shown to selectively down-modulate the adhesion/migration factors chemokine receptor-4 (Cxcr4) and integrin alpha-4 (Itga4) and to up-modulate growth differentiation factor-3 (Gdf3), oncostatin-M (OncoM), and podocalyxin like-1 (PODXL). For PODXL, Epo dose–dependent expression of this CD34-related sialomucin was discovered in Kit+CD71high proerythroblasts and was sustained at subsequent Kit−CD71high and Ter119+ stages. In vivo, Epo markedly induced PODXL expression in these progenitors and in marrow-resident reticulocytes. This was further associated with a rapid release of PODXL+ reticulocytes to blood. As studied in erythroblasts expressing minimal Epo receptor (EpoR) alleles, efficient PODXL induction proved dependence on an EpoR-PY343 Stat5 binding site. Moreover, in mice expressing an EpoR-HM F343 allele, compromised Epo-induced PODXL expression correlated with abnormal anucleated red cell representation in marrow. By modulating this select set of cell-surface adhesion molecules and chemokines, Epo is proposed to mobilize erythroblasts from a hypothesized stromal niche and possibly promote reticulocyte egress to blood.
Interaction between the Helicobacter pylori CagA and α‐Pix in Gastric Epithelial AGS Cells
Authors: BAEK HYE YEON , WEON LIM JOO , KIM HYEYOUNG
Published: April 2007

Abstract:  The gastric pathogen Helicobacter pylori (H. pylori) translocates the CagA protein into epithelial cells by a type IV secretion process. Upon translocation into the host cell cytosol, CagA undergoes tyrosine phosphorylation. Phosphorylation of CagA occurs within the C terminus of the protein and is mediated by members of the Src family of tyrosine kinases. Phosphorylation of CagA induces the dephosphorylation of as yet unidentified cellular proteins, rearrangements of the host cell actin cytoskeleton, and cell scattering. This article aims to determine the cellular protein that interacts with CagA. Gastric epithelial AGS cells were stimulated with CagA‐positive H. pylori (NCTC11637, at a bacteria/cell ratio of 500:1) and cultured in antibiotic‐free medium. Proteins were isolated from the cells with or without H. pylori infection. CagA‐interactive protein was determined by immunoprecipitation using anti‐CagA antibody and proteomic analysis. We found that α‐Pix interacts with CagA and α‐Pix was constitutively expressed in AGS cells. Upon H. pylori stimulation, CagA was translocated into the cells and the expression of α‐Pix (PAK‐interactive exchange factor) was increased in AGS cells time dependently. The interaction of α‐Pix with CagA was increased by H. pylori infection in AGS cells. Phosphorylation of CagA induces the dephosphorylation of α‐Pix in AGS cells. α‐Pix is a family of PAK‐binding proteins that strongly activates PAK (p21‐activated tyrosine kinase). PAK regulates changes in gene expression and mediates actin cytoskeletal and cell morphological changes. The novel finding of this study is that phosphorylation of CagA induces the dephosphorylation of α‐Pix, which may modulate cytoskeletal changes of gastric epithelial cells through PAK.
Analysis of Tissue Distribution of TNF‐α, TNF‐α‐Receptors, and the Activating TNF‐α–Converting Enzyme Suggests Activation of the TNF‐α System in the Aging Intervertebral Disc
Authors: BACHMEIER BEATRICE E. , NERLICH ANDREAS G. , WEILER CHRISTOPH , PAESOLD GÜNTHER , JOCHUM MARIANNE , BOOS NORBERT
Published: April 2007

Abstract:  We immunohistochemically analyzed the expression and localization of TNF‐α, its receptors TNF‐RI and ‐RII, and the TNF‐α‐activating enzyme TACE in human autopsy (n= 63) and surgical (n= 35) lumbar intervertebral disc samples. In parallel, the TNF‐α‐mRNA was quantified by reverse transcriptase‐polymerase chain reaction (RT‐PCR).
All samples were morphometrically evaluated for the proportion of positively labeled cells in the different anatomical regions of the disc. We detected a significant and comparable expression of all four parameters beginning in young adult age (c. 18 years
) and being most extensive in the nucleus pulposus. This level was slightly reduced in older age discs. The annulus fibrosus contained significantly less labeled cells. In accord, the number of TNF‐α‐transcripts was elevated in most cases with immunohistochemical TNF‐α expression. We provide clear evidence that TNF‐α is expressed in discs of increasing age, which correlates with histomorphological signs of disc degeneration. In consequence, TNF‐α seems to be activated (by the converting enzyme TACE) and biologically active through its receptors in human lumbar disc tissue.
Altered Subcellular Distribution of the Alzheimer's Amyloid Precursor Protein Under Stress Conditions
Authors: DOMINGUES SARA C.T.S. , HENRIQUES ANA GABRIELA , WU WENJUAN , Da CRUZ e SILVA EDGAR F. , Da CRUZ e SILVA ODETE A.B.
Published: April 2007

Abstract:  Altered metabolism of the Alzheimer's amyloid precursor protein (APP) appears to be a key event in the pathogenesis of Alzheimer's disease (AD), and both altered phosphorylation and oxidative stress appear to affect the production of the toxic Abeta fragment. Our results show that altered processing of APP was observed under conditions of stress induced by sodium azide in the presence of 2‐deoxy‐d‐glucose (2DG). As previously reported, the production of the secreted fragment of APP (sAPP) was inhibited. Using APP‐GFP fusion proteins, we show that 2DG causes the accumulation/delay of APP in the endoplasmic reticulum (ER)/Golgi (G). The 751 isoform accumulated preferentially in the G, whereas the 695 isoform was blocked preferentially at the ER. This effect was augmented in the presence of sodium azide. APP subcellular distribution was also affected at the plasma membrane. The involvement of protein phosphorylation in APP subcellular localization was reinforced by the effect of drugs, such as phorbol 12‐myristate 13‐acetate (PMA), since APP was completely depleted from the membrane in the presence of 2DG and PMA. Thus, the hypothesis that APP is processed in a phosphorylation‐dependent manner and that this may be of clinical relevance appears to hold true even under stress conditions. Our results provide evidence for a role of protein phosphorylation in APP sorting under stress conditions and contribute to the understanding of the molecular basis of AD.
Scheduling Umpire Crews for Professional Tennis Tournaments
Authors: Farmer Adam , Smith Jeffrey S. , Miller Luke T.
Published: April 2007

Professional tennis organizations, such as the United States Tennis Association (USTA), the Association of Tennis Professionals (ATP), the International Tennis Federation (ITF), and the Women’s Tennis Association (WTA), host tennis tournaments throughout the world. At these tournaments, chief umpires assign and schedule line umpires for every match. For most tournaments, they perform this task manually, which can be cumbersome for large tournaments. For large tournaments, such as the US Open, they can use software developed to facilitate scheduling. Unfortunately, the software package currently available often creates suboptimal or infeasible schedules that must be manually adjusted. We developed a program based on optimization that automates the scheduling procedure. Our program consistently provides high-quality schedules in as little as 25 percent of the time taken with other methods.
Book Reviews
Authors: Lev Benjamin
Published: April 2007

The range of books reviewed is wide, covering theory and applications in operations research, statistics, management science, econometrics, mathematics, computers, and information systems (no software is reviewed). In addition, we include books in other fields that emphasize technical applications. Publishers who wish to have their books reviewed should send them to Professor Benjamin Lev. We list the books received; not all books received can be reviewed because space is limited. Those who would like to review books are urged to send me their names, addresses, and specific areas of expertise. We commission all reviews and do not accept unsolicited book reviews. Readers are encouraged to suggest books that might be reviewed or to ask publishers to send me copies of such books.

The authors or editors of the books reviewed in this issue are Oliver Cappé, Eric Moulines, Tobias Rydén, Timothy Coelli, D. S. Prasada Rao, Christopher J. O’Donnell, George E. Battese, Mehmed M. Kantardzic, Jozef Zurada, André Langevin, Diana Riopel, Stefan Voss, and David L. Woodruff.
Decision-Centric Active Learning of Binary-Outcome Models
Authors: Saar-Tsechansky Maytal , Provost Foster
Published: April 2007

It can be expensive to acquire the data required for businesses to employ data-driven predictive modeling—for example, to model consumer preferences to optimize targeting. Prior research has introduced “active-learning” policies for identifying data that are particularly useful for model induction, with the goal of decreasing the statistical error for a given acquisition cost (error-centric approaches). However, predictive models are used as part of a decision-making process, and costly improvements in model accuracy do not always result in better decisions. This paper introduces a new approach for active data acquisition that specifically targets decision making. The new decision-centric approach departs from traditional active learning by placing emphasis on acquisitions that are more likely to affect decision making. We describe two different types of decision-centric techniques. Next, using direct-marketing data, we compare various data-acquisition techniques. We demonstrate that strategies for reducing statistical error can be wasteful in a decision-making context, and show that one decision-centric technique in particular can improve targeting decisions significantly. We also show that this method is robust in the face of decreasing quality of utility estimations, eventually converging to uniform random sampling, and that it can be extended to situations where different data acquisitions have different costs. The results suggest that businesses should consider modifying their strategies for acquiring information through normal business transactions. For example, a firm such as Amazon.com that models consumer preferences for customized marketing may accelerate learning by proactively offering recommendations—not merely to induce immediate sales, but for improving recommendations in the future.
Dispositional and situational learning goals and children's self‐regulation
Authors: Hole Jennifer L. , Crozier W. Ray.
Published: April 2007

Background.Little research has examined interactions between self‐reported dispositional and experimentally manipulated situational group orientations in their effect on self‐regulation.

Aims.The aim of the study was to investigate the effect of dispositional and situational learning goal orientation on children's self‐efficacy and engagement and persistence at a puzzle task.

Sample.A self‐report learning goal orientation scale was completed by 110 children, aged 9–11 years. Fifty‐three children (24 girls) selected to be high and low on the scale participated in the experiment.

Method.Half of the children were given instructions designed to evoke learning goals, while the remainder received performance goal instructions. Children attempted a difficult puzzle task on two occasions, when measures were made of self‐regulatory behaviours.

Results and conclusions.Children assigned to the learning goal instruction were more likely to persist at the task until the end of the allotted time, displayed more on‐task behaviour and engaged in more autonomous help‐seeking. These effects were more pronounced following the first task, which all children had been unable to complete. Dispositional task orientation did not predict individual differences on these measures. The findings are interpreted in terms of learned helplessness and self‐worth theory.
Incipient adult personality: The NEO‐PI‐3 in middle‐school‐aged children
Authors: Costa Paul T. , McCrae Robert R. , Martin Thomas A.
Published: April 2007

This study administered the NEO Personality Inventory‐3 (NEO‐PI‐3), a more readable version of an adult measure of the Five‐Factor Model, to 449 boys and girls aged 12 and 13, who described themselves or a peer. Analyses of readability, reliability, factor structure, and convergent and discriminant validity suggested that the NEO‐PI‐3 can be appropriately used in this age group. Personality traits in children of this age closely resemble in structure and functioning the traits of older adolescents and adults. Most gender differences known from studies of adults are found in this age group, and mean levels show continuity with older groups. The NEO‐PI‐3 appears to be a useful instrument for research, and potentially for clinical applications, in middle‐school‐aged children.
Common hippopotamus ( Hippopotamus amphibius ): a survey on the River Djerem, Mbam-Djerem National Park, Cameroon / Hippopotames ( Hippopotamus amphibius ): l'inventaire des populations sur la rivière Djerem, Parc National de Mbam Djerem, Cameroun
Authors: Nchanji Anthony Chifu , Fotso Roger C.
Published: April 2007

Information on the population of common hippopotamus ( Hippopotamus amphibius ) in Cameroon is limited. Consequently, management decisions are based on guesses. We surveyed common hippos on the River Djerem in Mbam-Djerem National Park, from April to June 2001 by sailing on the river at 1.5 km/h and counting hippopotamus that emerged to the water surface. We also recorded their tracks along the river banks. We found at least 18 hippos in April and 79 during May–June on the river, suggesting that there were either different numbers at each of the periods or approximately the same numbers, but with individuals responding differently to the physiological and noise stimuli used in the study. However, the observation of numerous fresh outlet tracks of hippos at pools where they were not directly sighted suggests higher numbers on the river during each of the periods. Hunting of hippopotamus in the past for trophies (canines) threatened their survival and accounts for the relatively low numbers observed compared to an earlier survey in the River Bénoué. There are hopes for a future population increase with increased law enforcement in the recently created Mbam-Djerem National Park.
Effect of precipitate shapes on fracture toughness in extruded Mg–Zn–Zr magnesium alloys
Authors: Somekawa Hidetoshi , Singh Alok , Mukai Toshiji
Published: April 2007

A commercial Mg–6 wt% Zn–0.5 wt% Zr (ZK60) alloy was used to investigate the effect of precipitate shapes on fracture toughness. The ZK60 alloy was extruded at a temperature of 653 K (extruded alloy). The extruded alloy was annealed at 633 K for 86.4 ks (annealed alloy), and then the annealed alloy was aged at 448 K for 100 ks (aged alloy). The average grain size in all the conditions was about the same, 13.5 ± 1.0 μm. The extruded and aged alloys had different shaped precipitates: spherical and rod shaped precipitates, respectively. The plane-strain fracture toughness KIC of the extruded, annealed, and aged alloys were estimated to be 22.4, 20.2, and 21.0 MPam1/2, respectively, by the stretched zone analysis. Transmission electron microscopy (TEM) observations showed that the deformation during the fracture toughness test was dominated by a dislocations on the basal slip planes in all the conditions. Such dislocations are commonly activated in magnesium alloys during the tensile and compression tests. The spherical shaped precipitates were found to be more effective than the rod shaped precipitates for improving the fracture toughness in the magnesium alloy.
Thermomechanical effects on phase transformations in single-crystal Cu–Al–Ni shape-memory alloy
Authors: Zhang H.-S. , Komvopoulos K.
Published: April 2007

Single-crystal rods of Cu–Al–Ni shape-memory alloy fabricated from a molten pool of 82 wt% Cu, 14 wt% Al, and 4 wt% Ni by the Czochralski method were first heated to ∼870 °C and then quenched to obtain austenitic microstructures. Various microanalysis techniques were used to determine the chemical composition, microstructure, and phase-transformation temperatures of the produced alloy. Cyclic tensile tests with in situ temperature control demonstrated the occurrence of pseudoelastic deformation at elevated and close to phase-transformation temperatures and provided insight into the temperature dependence of the phase-transformation stress, damping characteristics, and cyclic straining of single-crystal Cu–Al–Ni alloy. The stress hysteresis observed in the pseudoelastic deformation cycles decreased at elevated temperatures. The stress response at different temperatures is associated with the formation, growth, and coalescence of martensite variants. Stress-induced phase-transformation mechanisms, coalescence of twin variants, and energy dissipation by pseudoelastic deformation are discussed in the context of experimental findings. The results illustrate the potential of single-crystal Cu–Al–Ni as a structural material for dynamic microsystems and temperature sensors.
Biocompatibility of Te–As–Se glass fibers for cell-based bio-optic infrared sensors
Authors: Wilhelm Allison A. , Lucas Pierre , DeRosa Diana L. , Riley Mark R.
Published: April 2007

The chemical stability and toxicity of Te–As–Se (TAS) infrared fibers are investigated. These fibers are used for biosensing applications that involve direct contact with live cultivated human cells. It is shown that TAS fibers exhibit a small oxidation layer after extended exposure to air. This layer is highly soluble in water and easily removed. However, the TAS glass itself is stable in water over several days. While oxidized fibers release arsenate ions, which result in toxic effects to the cells, fresh or washed fibers show no toxic effects. A good correlation is shown between surface etching and the disappearance of toxicity.
Ripening-assisted void formation in the matrix of lead-free solder joints during solid-state aging
Authors: Jang J.W. , Lin J.K. , Frear D.R. , Lee T.Y. , Tu K.N.
Published: April 2007

Void formation in lead-free solder joints, away from the joint interface, has been observed after solid-state aging. These voids are attached to intermetallic precipitates in the solder matrix, especially to those that are adjacent to the layered intermetallic at the joint interface. Two potential void formation mechanisms are discussed. The mechanism proposed to describe void formation is that a flux of vacancies is created due to volume contraction during solid-state reaction. The ripening process among the intermetallics also assists this process. Using the suggested mechanisms, the void size was estimated. This phenomenon differs from the classical Kirkendall void formation because it is a nonequilibrium state of void formation and stress generation.
Strength and fracture of Si micropillars: A new scanning electron microscopy-based micro-compression test
Authors: Moser B. , Wasmer K. , Barbieri L. , Michler J.
Published: April 2007

A novel method for in situ scanning electron microscope (SEM) micro-compression tests is presented. The direct SEM observation during the instrumented compression testing allows for very efficient positioning and assessment of the failure mechanism. Compression tests on micromachined Si pillars with volumes down to 2 μm3are performed inside the SEM, and the results demonstrate the potential of the method. In situ observation shows that small diameter pillars tend to buckle while larger ones tend to crack before failure. Compressive strength increases with decreasing pillar diameter and reaches almost 9 GPa for submicrometer diameter pillars. This result is in agreement with earlier bending experiments on Si. Difficulties associated with precise strain measurements are discussed.
Achievements in Systemic Therapies in the Pregenomic Era in Metastatic Breast Cancer
Authors: Colozza Mariantonietta , de Azambuja Evandro , Personeni Nicola , Lebrun Fabienne , Piccart Martine J. , Cardoso Fatima
Published: April 2007

Learning Objectives

After completing this course, the reader will be able to: Identify the available systemic therapies for metastatic breast cancer patients.Define the role of taxanes and targeted therapies in metastatic breast cancer patients.Discuss the most useful endocrine therapy in patients with metastatic breast cancer.

CME Access and take the CME test online and receive 1 AMA PRA Category 1 Credit™ at CME.TheOncologist.com
Medicinal Cannabis Does Not Influence the Clinical Pharmacokinetics of Irinotecan and Docetaxel
Authors: Engels Frederike K. , de Jong Floris A. , Sparreboom Alex , Mathot Ron A. A. , Loos Walter J. , Kitzen Jos J. E. M. , de Bruijn Peter , Verweij Jaap , Mathijssen Ron H. J.
Published: April 2007

Objective.

To date, data regarding the potential of cannabinoids to modulate cytochrome P450 isozyme 3A (CYP3A) activity are contradictory. Recently, a standardized medicinal cannabis product was introduced in The Netherlands. We anticipated an increased use of medicinal cannabis concurrent with anticancer drugs, and undertook a drug-interaction study to evaluate the effect of concomitant medicinal cannabis on the pharmacokinetics of irinotecan and docetaxel, both subject to CYP3A-mediated biotransformation.

Patients and Methods.

Twenty-four cancer patients were treated with i.v. irinotecan (600 mg, n = 12) or docetaxel (180 mg, n = 12), followed 3 weeks later by the same drugs concomitant with medicinal cannabis (200 ml herbal tea, 1 g/l) for 15 consecutive days, starting 12 days before the second treatment. Blood samples were obtained up to 55 hours after dosing and analyzed for irinotecan and its metabolites (SN-38, SN-38G), respectively, or docetaxel. Pharmacokinetic analyses were performed during both treatments. Results are reported as the mean ratio (95% confidence interval [CI]) of the observed pharmacokinetic parameters with and without concomitant medicinal cannabis.

Results.

Medicinal cannabis administration did not significantly influence exposure to and clearance of irinotecan (1.04; CI, 0.96–1.11 and 0.97; CI, 0.90–1.05, respectively) or docetaxel (1.11; CI, 0.94–1.28 and 0.95; CI, 0.82–1.08, respectively).

Conclusion.

Coadministration of medicinal cannabis, as herbal tea, in cancer patients treated with irinotecan or docetaxel does not significantly influence the plasma pharmacokinetics of these drugs. The evaluated variety of medicinal cannabis can be administered concomitantly with both anticancer agents without dose adjustments.
Oral Glutamine Is Effective for Preventing Oxaliplatin-Induced Neuropathy in Colorectal Cancer Patients
Authors: Wang Wei-Shu , Lin Jen-Kou , Lin Tzu-Chen , Chen Wei-Shone , Jiang Jeng-Kae , Wang Huann-Sheng , Chiou Tzeon-Jye , Liu Jin-Hwang , Yen Chueh-Chuan , Chen Po-Min
Published: April 2007

Learning Objectives

After completing this course, the reader will be able to: Identify the clinical features of oxaliplatin-induced neuropathy.Discuss the current approaches for managing chemotherapy-induced neuropathy.Explain the rationale for using glutamine in preventing oxaliplatin-induced neuropathy.

CME Access and take the CME test online and receive 1 AMA PRA Category 1 Credit™ at CME.TheOncologist.com
The Synergistic Effect of Prussian‐Blue‐Grafted Carbon Nanotube/Poly(4‐vinylpyridine) Composites for Amperometric Sensing
Authors: Li J. , Qiu J.‐D. , Xu J.‐J. , Chen H.‐Y. , Xia X.‐H.
Published: March 2007

Because of its high activity and selectivity toward the reduction of hydrogen peroxide and oxygen, Prussian blue (PB) is usually considered as an “artificial enzyme peroxidase” and has been extensively used in the construction of electrochemical biosensors. In this study, we report on the construction of amperometric biosensors via grafting PB nanoparticles on the polymeric matrix of multiwalled carbon nanotubes (MWCNTs) and poly(4‐vinylpyridine) (PVP). The MWCNT/PVP/PB composite films were synthesized by casting films of MWCNTs wrapped with PVP on gold electrodes followed by electrochemical deposition of PB on the MWCNT/PVP matrix. The electrode modified with the MWCNT/PVP/PB composite film shows prominent electrocatalytic activity toward the reduction of hydrogen peroxide, which can be explained by the remarkable synergistic effect of the MWCNTs and PB. Therefore, fast amperometric response of this sensor to hydrogen peroxide was observed with a detection sensitivity of 1.3 μA μM–1 of H2O2 per square centimeter area and a detection limit of 25 nM. These results are much better than those reported for PB‐based amperometric sensors. In addition, a glucose biosensor fabricated by casting an additional glucose oxidase (GOD) containing Nafion film above the MWCNT/PVP/PB composite film shows promise for the sensitive and fast detection of glucose. The observed high stability, high sensitivity, and high reproducibility of the MWCNT/PVP/PB composite films make them promising for the reliable and durable detection of hydrogen peroxide and glucose.
A Solution‐Processable High‐Coloration‐Efficiency Low‐Switching‐Voltage Electrochromic Polymer Based on Polycyclopentadithiophene
Authors: Wu C.‐G. , Lu M.‐I. , Chang S.‐J. , Wei C.‐S.
Published: March 2007

A solution‐processable electrochromic (EC) polymer, poly(4,4‐dioctyl‐cyclopenta[2,1‐b:3,4‐b′]‐dithiophene) (PDOCPDT) is prepared by means of chemical oxidative polymerization of the corresponding monomer. The UV‐vis spectrum of the spin‐coated PDOCPDT film displays an absorption maximum of 580 nm. Although the polymer is deep blue in its neutral state, it turns to transparent bluish after being oxidized. PDOCPDT film (thickness 120 nm) exhibits high coloration efficiency (CE)—as high as 932 C cm–2 at 580 nm, low response time (0.75 s), high optical density (0.75 at 580 nm), and high‐level stability for long term switch (it switches repetitively 1000 times with less than 8 % contrast loss). The electrochemical stability and redox potentials of PDOCPDT films are independent of film thickness (50–180 nm) and active area (up to 2 cm × 2 cm). Nevertheless, optical contrast increases as the film thickness increases, although the CE and response time changes irregularly with the film thickness. The good EC properties combined with the easy film fabrication process make PDOCPDT a notable candidate for application in EC devices. (ECDs) A simple transmissive‐type ECD with good CE using PDOCPDT film as an active layer is also demonstrated.
Photonic Crystals from Ordered Mesoporous Thin‐Film Functional Building Blocks
Authors: Fuertes M. C. , López‐Alcaraz F. J. , Marchi M. C. , Troiani H. E. , Luca V. , Míguez H. , Soler‐Illia G. J. A. A.
Published: March 2007

Environment‐sensitive Bragg reflectors are built using functional mesoporous thin films as building blocks. Tuning of optical properties is achieved by changing the composition or porosity of the slabs or the introduction of planar defects. Sorption or capillary condensation of molecules into the pore system results in a 10–40 nm photonic bandgap (PBG) shift. Organic functions added to the pore surface change the response, permitting tailoring of the selectivity towards small‐size molecules.
Convection, diffusion and reaction in a nonisothermal, porous catalyst slab
Authors: Cardoso Silvana S. S. , Rodrigues Alírio E.
Published: March 2007

The problem of simultaneous convection, diffusion and reaction inside a porous catalyst slab is considered. A combination of perturbation and integral mathematical techniques are used to derive approximate analytical solutions for the concentration and temperature profiles, as well as for the maximum temperature and the effectiveness factor, for a first order, nonisothermal reaction. Three regimes of operation are characterized: regime I, in which convection and diffusion are dominant (small Thiele modulus); regime II, in which diffusion and reaction are dominant (large Thiele modulus); and regime III, in which convection and reaction dominate (intermediate Thiele modulus). Our analytical solutions for each of these regimes are validated by comparison with previous results from numerical simulations. © 2007 American Institute of Chemical Engineers AIChE J, 2007
Synchronous and asynchronous SMB processes for gas separation
Authors: Mota José P. B. , Esteves Isabel A. A. C. , Eusébio Mário F. J.
Published: March 2007

The simulated‐moving bed (SMB) is now a well established adsorption process for obtaining high‐purity products at a similarly high‐recovery. In principle the SMB process can be applied to gases, and has been, but application has been limited. Here, we re‐examine the SMB process for separation of gaseous components in the light of recent developments in novel cyclic operating schemes and advanced optimization tools. A novel single‐column experimental setup is employed to demonstrate the feasibility of the process, explore the effect of its major operating parameters, and illustrate the performance enhancements that are obtained by using an advanced cyclic operation scheme, such as the asynchronous shifting of the inlet/outlet ports. The experimental feasibility and effectiveness of gas‐phase SMB are assessed by running and comparing optimized configurations for the separation of CH4/CO2 over activated carbon using nitrogen as carrier gas. For this separation, the asynchronous configuration always outperforms the classical SMB scheme, both in productivity and eluent consumption, except at very low‐feed throughput where both schemes are coincident. At higher‐feed flow rates, the asynchronous scheme quickly diverges from a four‐zone, closed‐loop configuration towards a three‐zone, open‐loop process with a 50.6% increase in feed throughput, and 10% reduction on eluent gas consumption. © 2007 American Institute of Chemical Engineers AIChE J, 2007
Floodwater exposure and the related health symptoms among firefighters in New Orleans, Louisiana 2005
Authors: Tak SangWoo , Bernard Bruce P. , Driscoll Richard J. , Dowell Chad H.
Published: April 2007

Background

Concerns over increased reports of physical health symptoms thought to be related to floodwater exposure among New Orleans firefighters prompted a health hazard evaluation of firefighters following Hurricane Katrina.

Methods

A questionnaire assessing health symptoms possibly related to the response to Hurricane Katrina was administered to all New Orleans Fire Department (NOFD) personnel within 3 months of the disaster. Descriptive statistics were compiled and prevalence ratios (PR) were estimated for covariates using generalized linear models with Log link and Poisson distribution.

Results

Of the 525 firefighters who completed the questionnaire (77% participation), 201 (38%) reported one or more new‐onset respiratory symptoms, such as sinus congestion (145 [28%]), throat irritation (92 [17%]), and cough (124 [24%]). Skin rash was reported by 258 (49%) of respondents, 414 (79%) reported skin contact with floodwater, and 165 (32%) reported contact with floodwater on multiple days. In multivariate analyses adjusting for age, gender, and smoking, firefighters who had floodwater contact with skin and either nose/mouth or eyes (224, 44%) had an increased rate of new‐onset upper respiratory symptoms (PR = 1.9; 95% confidence interval [CI], 1.1, 3.1), and skin rash (PR = 2.1; 95% CI, 1.4, 3.2) compared to those not exposed to the floodwater.

Conclusions

Response workers involved with floodwater should minimize direct skin and mucosal contact with floodwater if possible through the use of appropriate personal protective equipment, such as goggles, safety glasses with side shields, or full‐face shields. Am. J. Ind. Med. 50:377–382, 2007. © 2007 Wiley‐Liss, Inc.
Gas sorption in polymers, molecular sieves, and mixed matrix membranes
Authors: Moore Theodore T. , Koros William J.
Published: March 2007

Gas sorption has been an underutilized technique for characterizing organic–inorganic hybrid (mixed matrix) membranes. Sorption in these membranes, which are composed of rigid inorganic domains, such as zeolites, dispersed in a polymer matrix, should be approximately additive. Sorption in the neat polymers and zeolites were first measured to demonstrate that sorption in mixed matrix membranes is approximately additive in the absence of other effects. Sorption in mixed matrix membranes was demonstrated to be additive. This extends to cases where sorption in one or both phases of the mixed matrix membrane is affected by an outside contaminant. For example, zeolite 4A is extremely hydrophilic and easily affected by contaminants from processing or from the test gases. Zeolite 4A encapsulated within a polymer matrix can still be affected by these same components, and this causes sorption lower than predicted based on that in unaffected polymers and sieves. This sorption analysis has proven to be very important in understanding the permeabilities and selectivities of mixed matrix membranes. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 4053–4059, 2007
Friction and wear mechanisms of PA66/PPS blend reinforced with carbon fiber
Authors: Chen Zhaobin , Liu Xujun , Lü Renguo , Li Tongsheng
Published: March 2007

The mechanical and tribological properties of carbon fiber (CF) reinforced polyamide 66 (PA66)/polyphenylene sulfide (PPS) blend composite were studied in this article. It was found that CF reinforcement greatly increases the mechanical properties of PA66/PPS blend. The friction coefficient of the sample decreases with the increase of CF content. When CF content is lower (below 30%), the wear resistance is deteriorated by the addition of CF. However, the loading of higher than 30% CF significantly improves the tribological properties of the blend. The lowest friction coefficient (0.31) and the wear volume (1.05 mm3) were obtained with the PA66/PPS blend containing 30% CF. The transfer film and the worn surface formed by sample during sliding were examined by scanning electron microscopy. The observations revealed that the friction coefficient of PA66/PPS/CF composite depends on the formation and development of a transfer film on the counterface. The abrasive wear caused by ruptured CFs (for lower CF content) and the load bearing ability of CFs (for higher CF content) are the major factors affecting the wear volume. In addition, the improvements of mechanical properties, thermal conductivity, and self‐lubrication of bulk CFs are also contributed to the wear behavior of PA66/PPS/CF composite. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007
Recoverable surface modification using dendritically fluorocarbon‐functionalized poly(methyl methacrylate)
Authors: Thompson Richard L. , Narrainen Amilcar Pillay , Eggleston Stuart M. , Ansari Imtiyaz A. , Hutchings Lian R. , Clarke Nigel
Published: March 2007

Dendritically fluorocarbon‐functionalized poly(methyl methacrylate) (PMMA) has been explored as a robust surface‐modifying additive in PMMA blends. These functionalized materials, denoted FxPMMAy, where x is the number of C8F17 fluorocarbon groups per dendron connected to a PMMA chain of y kg/mol, have been synthesized by living radical polymerization. These materials adsorb efficiently to the surfaces of their blends with unfunctionalized PMMA, resulting in increased hydrophobicity and lipophobicity. Contact‐angle goniometry has indicated a substantial reduction in the surface energy toward polytetrafluoroethylene‐like surface properties in the case of pure F4PMMA8.6 and substantial, but incomplete fluorocarbon surface coverage at a lower FxPMMAy concentration. The partial coverage has been confirmed by Rutherford backscattering and, together with the weak dependence of the surface modification on the FxPMMAy structure, indicates incomplete equilibrium of the surface adsorption. The modified surfaces are quite durable with respect to abrasion under water but are progressively eroded when the double‐wipe test is carried out with acetone. FxPMMAy, dispersed in the remaining film, acts as a reservoir of spare functional groups, from which the damaged surface may be replenished, leading to the recovery of the modified surface properties. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007
Poly(ϵ‐caprolactone)‐functionalized carbon nanofibers by surface‐initiated ring‐opening polymerization
Authors: Wang Kai , Li Wenwen , Gao Chao
Published: March 2007

Carbon nanofibers (CNFs) were covalently functionalized with biodegradable poly(ϵ‐caprolactone) (PCL) by in situ ring‐opening polymerization (ROP) of ϵ‐caprolactone in the presence of stannous octoate. Surface oxidation treatment of the pristine CNFs afforded carboxylic CNFs (CNF‐COOH). Reaction of CNF‐COOH with excess thionyl chloride (SOCl2) and glycol produced hydroxyl‐functionalized CNFs (CNF‐OH). Using CNF‐OH as macroinitiator, PCL was covalently grafted from the surfaces of CNFs by ROP, in either the presence or absence of sacrificial initiator, butanol. The grafted PCL content was achieved as high as 64.2 wt %, and can be controlled to some extent by adjusting the feed ratio of monomer to CNF‐OH. The resulting products were characterized by FTIR, NMR, Raman spectroscopy, TGA, DSC, SEM, TEM, HRTEM, and XRD. Core–shell nanostructures were observed under HRTEM for the PCL‐functionalized CNFs because of the thorough grafting. The PCL‐grafted CNFs showed different melting and crystallization behaviors from the mechanical mixture of PCL and CNF‐OH. This approach to PCL‐functionalized CNFs opens an avenue for the synthesis, modification, and application of CNF‐based nanomaterials and biomaterials. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007
Free volume properties of thermoplastic polyurethane/polymethylmethacrylate blends: Evidence of interchain interaction
Authors: Patrício P. S. O. , Silva G. G. , Machado J. C.
Published: March 2007

A polymer blend based on thermoplastic elastomeric polyurethane and polymethylmethacrylate (TPU/PMMA) has been studied by positron annihilation lifetime spectroscopy (PALS) and thermomechanical analysis. Thermomechanical analysis allowed the determination of two glass transitions for the blends in the overall range of compositions. The first one (Tg1) showed a constant value of −45°C for all blends, the same value of the pure TPU. The second glass transition (Tg2), which is associated with a PMMA rich phase, presented variations with composition. Tg2 showed minimum values for the blends in the 20–40 wt % TPU range, which indicates increase of interaction in this composition region. PALS systematic investigation allowed the determination of relative mean free volume fractions, fv/C, and binary interchain interaction parameters, β. These parameters exhibited a noticeable negative deviation from additivity in all range of composition and minima for the 20 wt % TPU blend. PALS results were interpreted as associated to a strong attractive interchain interaction between TPU and PMMA in the PMMA rich phase which contracts the free volume fraction of the blends. Moreover, the miscibility achieved in the PMMA rich phase would allow a good adhesion between this phase and the TPU phase, which was corroborated by scanning electron microscopy images. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007
Composites of polymeric gels and magnetic nanoparticles: Preparation and drug release behavior
Authors: François Nora J. , Allo Sabina , Jacobo Silvia E. , Daraio Marta E.
Published: March 2007

The article is concerned with the preparation of polymer–iron oxide nanocomposites and the study as drug‐delivery matrices under the influence of applied magnetic field. Biocompatible materials were prepared by incorporating an aqueous ferrofluid in poly(vinyl alcohol) and scleroglucan (SCL) hydrogels, loaded with theophylline as model drug for release studies. Thein vitrorelease profile was obtained using a flat Franz cell and the kinetic parameters were derived applying a semiempirical power law. A magnetic characterization of nanoparticles contained in the ferrofluid was performed by obtaining the magnetization curve. For both systems, the observed drug release profiles decreased when a uniform external magnetic field is applied suggesting they can be used as environmental responsive matrices for biomedical applications. Dynamic rheological measurements show that a higher storage modulus and a more compact structure are obtained by incorporating the ferrofluid into the hydrogels. These rheological results and environmental electron scanning microscopy micrographs point to an understanding of release behavior once the magnetic field is applied. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007
Physicochemical properties and fracture behavior of soy‐based resin
Authors: Shabeer A. , Sundararaman S. , Chandrashekhara K. , Dharani L. R.
Published: March 2007

A soy‐based resin was prepared by the process of transesterfication and epoxidation of regular food‐grade soybean oil. The soy‐based resin was used as a reactive diluent and also as a replacement of bisA epoxy resin in an anhydride‐cured polymer. The curing efficiency of soy epoxy resin was studied using differential scanning calorimetry. Physicochemical properties and fracture behavior of soy‐based resin polymers were studied using dynamic mechanical analysis and fracture toughness measurements, respectively. Toughness measurements were carried out using the compact tension geometry following the principles of linear elastic fracture mechanics. Tests showed that the addition of soy‐based epoxy resin to the base epon resin improved the toughness of the blend. Morphology of the fractured specimens has been analyzed by scanning electron microscopy. The soy‐based resins hold great potential for environmentally friendly, renewable resource based, and low cost materials for structural applications. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007
Localization, quantification, and characterization of tuftelin in soft tissues
Authors: Leiser Yoav , Blumenfeld Anat , Haze Amir , Dafni Leah , Taylor Angela L. , Rosenfeld Eli , Fermon Eran , Gruenbaum‐Cohen Yael , Shay Boaz , Deutsch Dan
Published: March 2007

Tuftelin was initially found in the developing and mature extracellular enamel. Here we describe our novel discovery of tuftelin cellular distribution (protein and mRNA) in six soft tissues. The expression levels of tuftelin mRNA were significantly higher in mouse kidney and testis, in which oxygen levels are hovering closely to hypoxia under normal conditions. Anat Rec, 2007. © 2007 Wiley‐Liss, Inc.