bluuebunny/crossref_metadata_2025 huggingface dataset:
Room temperature prevulcanization of natural rubber latex using xanthate
Authors: Sasidharan K. K. , Palaty Shiny , Gopalakrishnan K. S. , George K. E. , Joseph Rani
Published: August 2004

Room temperature prevulcanization of natural rubber latex using a combination of xanthate and a dithiocarbamate accelerator system was investigated. The mechanical properties of the room temperature prevulcanized latex compound was compared with that of a dithiocarbamate system and a commercial prevulcanized latex. Films were prepared from the room temperature prevulcanized latex, commercial prevulcanized latex, and prevulcanized latex prepared by heating latex compound at 55°C. The mechanical properties were compared. The results show that xanthate in combination with dithiocarbamate can bring about prevulcanization at room temperature. The latex film prepared from the room temperature prevulcanized latex compound gives better clarity and tensile properties than conventional and commercial samples. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 1164–1174, 2004
Synthesis of block and grafted copolymers containing spacer‐linked chromophore based on cellulose and polyethylene glycol
Authors: Namazi H. , Jafari Rad S.
Published: August 2004

A series of block copolymers from hydroxyl‐terminated cellulose triacetate (HCTA) and cellulose triacetate (CTA) with polyethylene glycol (PEG) were prepared. To activate terminal acid groups in the polyethylene glycols, acid groups were first converted to the acetyl groups with chlorination reaction. In the second series, the cellulose triacetate, having fully substituted acetate groups, was hydrolyzed by the acid catalyst method by using acetic acid and small percentages of water. Then cellulose derivatives containing 4‐(4‐nitrophenylazo)‐1‐naphthol (Magneson II) as a chromophore and long hydrocarbon side chains were prepared. The compound 4′‐bromobutoxy‐4‐(4‐nitrophenylazo)naphthalene was first synthesized from 4‐(4‐nitrophenylazo)‐1‐naphthol and 1,4‐dibromobutane. The alkylated chromophore reacted with prepared cellulosic and oligocellulosic copolymers in the solution of dimethyl sulfoxide to produce cellulose ethers having the desired chromophore. Polymers containing a mixture of alkyl side chains were also prepared by the addition of 1‐bromododecane to the reaction mixture. The above method was used for the preparation of (dodecyl) [4′‐butoxy‐4‐(4‐nitrophenylazo)naphthalene] (CTA‐co‐PEG2000) and (dodecyl) [4′‐butoxy‐4‐(4‐nitrophenylazo)naphthalene] (HCTA‐co‐PEG2000). The structure of products was determined by FTIR, 1H‐NMR spectroscopy, GPC, and the intrinsic viscosity measurement. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 1175–1185, 2004
Continuous ultrasonic devulcanization of unfilled butyl rubber
Authors: Feng Wenlai , Isayev A. I.
Published: August 2004

The devulcanization of resin‐cured unfilled butyl rubber with a grooved‐barrel ultrasonic reactor under various processing conditions was carried out. The experiments indicated that, because of the lower unsaturation and good thermal stability of butyl rubber, its devulcanization could be successfully accomplished only under severe ultrasonic‐treatment conditions. Gel permeation chromatography measurements were carried out for the virgin gum and sol part of devulcanized samples to study the changes in the rubber network during the devulcanization process. The obtained data showed a significant molecular weight reduction and a broadening of the molecular weight distribution upon devulcanization, which indicated that the devulcanization and degradation of butyl rubber occurred simultaneously. The rheological properties showed that devulcanized butyl rubber was more elastic than the virgin gum. The vulcanizates of the devulcanized butyl rubber showed mechanical properties comparable to those of the virgin vulcanizate. The thermal behaviors of the virgin and devulcanized butyl rubber were different and were correlated to the double‐bond content. The structural characteristics of the devulcanized butyl rubber were simulated with the Dobson–Gordon theory of rubber network statistics. A fairly good agreement between the experimental data and theoretical prediction was achieved. The simulation of devulcanized butyl rubber indicated that the rate of crosslink rupture was much higher than that of the main chain. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 1316–1325, 2004
Influence of fiber treatment on the performance of sisal–polypropylene composites
Authors: Mohanty Smita , Verma Sushil K. , Nayak Sanjay K. , Tripathy Sudhansu S.
Published: August 2004

This article concerns the effectiveness of MAPP as a coupling agent in sisal–polypropylene composites. The fiber loading, MAPP concentration, and fiber treatment time influenced the mechanical properties of the composites. It was observed that the composites prepared at 21 volume percent of fibers with 1% MAPP concentration exhibits optimum mechanical strength. SEM investigations confirmed that the increase in properties is caused by improved fiber‐matrix adhesion. The viscoelastic properties of the treated and untreated composites were also studied. From the storage modulus versus temperature plots, an increase in the magnitude of the peaks was observed with the addition of MAPP and fiber reinforcement, thus showing an improvement in stiffness of the treated composites. The damping properties of the composites, however, decreased with the addition of the fibers and MAPP. The thermal properties of the composites were analyzed through DSC and TGA measurements. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 1336–1345, 2004
Zur Anwendung von Expositionsklassen bei Parkhäusern
Authors: Curbach Manfred , Zaus Hendrik , Henke Peter , Meyer Lars , Proske Dirk
Published: August 2004

Der Beitrag beschreibt die Anwendung der Expositionsklassen von DIN 1045‐1 für direkt befahrene Parkdecks und aufgehende Bauteile in Parkhäusern. Die Auswahl der Expositionsklassen für Parkhäuser wurde in den letzten Monaten intensiv in der Fachwelt diskutiert. Als Ergebnis dieser Diskussion wird der DBV in den nächsten Monaten ein Merkblatt “Parkhäuser und Tiefgaragen” veröffentlichen. Neben der genannten Problematik werden auch weiterführende Nachweise der Dauerhaftigkeit erwähnt.
Vorgefertigte Parkhäuser aus hochfestem Beton
Authors: Hegger Josef , Roeser Wolfgang , Bachmann Hubert , Nitsch Andreas
Published: August 2004

Unter Anwendung hochfester Werkstoffe, innovativer Bewehrungstechnik und der neuen Normengeneration wurden architektonisch ansprechende Parkhäuser aus Betonfertigteilen entwickelt. Die geringen Bauteilabmessungen ermöglichen hierbei filigrane Tragwerke mit einer hellen und freundlichen Gesamtwirkung.
Schäden an Parkdecks mit unzureichender rißbreitenbeschränkender Bewehrung
Authors: Eßer Angelika , Schöppel Klaus
Published: August 2004

Bei der Konstruktion von Parkdecks wird oftmals eine rißbreitenbeschränkende Bewehrung nur unzureichend bemessen und eingebaut. Dieser Konstruktionsmangel führt im Regelfall zu einer unkontrollierten Rißbildung. Um die Dauerhaftigkeit des Bauwerks für die vorgesehene Nutzungsdauer dennoch gewährleisten zu können, sind Schutz‐ und Instandsetzungsmaßnahmen erforderlich, wie z. B. das Beschichten der Parkdeckoberflächen mit rißüberbrückenden Systemen, u. U. in Kombination mit vorherigen Füllmaßnahmen der Risse. Um die witterungsbedingten Rißbreitenänderungen möglichst realistisch erfassen zu können, werden Messungen der Rißbreitenänderungen unter Last und infolge von Temperaturschwankungen empfohlen. Aufgrund dieser Meßergebnisse kann eine Abschätzung der zu erwartenden Rißbewegungen getroffen werden, wie ein Beispiel zeigt.
Parkhaussanierungen
Authors: Roeske Dieter
Published: August 2004

Parkdecks sind als Außenbauteile hohen Beanspruchungen ausgesetzt. Leider wird oft an den Anforderungen “vorbeigeplant und ‐ausgeführt” und die dann notwendigen Sanierungen aus Kostengründen viel zu lange hinausgezögert. Im Sinne einer langfristigen Wert‐ und Gebäudeerhaltung ist es deshalb umso wichtiger, fällige Sanierungen so zu planen und auszuführen, daß sie objektbezogen und technisch richtig, dauerhaft sowie ökonomisch sinnvoll sind. Vor diesem Hintergrund werden anforderungsgerechte Lösungen mit Flüssigkunststoffen aufgezeigt, unter besonderer Berücksichtigung von Detailausbildungen und Lösungen für stark beanspruchte Bereiche (z. B. Rampen).
Statistical mechanics of protein folding by cluster distance geometry
Authors: Crippen Gordon M.
Published: August 2004

This is our second type of model for protein folding where the configurational parameters and the effective potential energy function are chosen in such a way that all conformations are described and the canonical partition function can be evaluated analytically. Structure is described in terms of distances between pairs of sequentially contiguous blocks of eight residues, and all possible conformations are grouped into 71 subsets in terms of bounds on these distances. The energy is taken to be a sum of pairwise interactions between such blocks. The 210 energy parameters were adjusted so that the native folds of 32 small proteins are favored in free energy over the denatured state. We then found 146 proteins having negligible sequence similarity to any of the training proteins, yet the free energy of the respective correct native states were favored over the denatured state. © 2004 Wiley Periodicals, Inc. Biopolymers, 2004
Multiple‐species candidemia in patients with cancer
Authors: Boktour Maha R. , Kontoyiannis Dimitrios P. , Hanna Hend A. , Hachem Ray Y. , Girgawy Essam , Bodey Gerald P. , Raad Issam I.
Published: August 2004

BACKGROUND

Candidemia is a common cause of bloodstream infections in patients with cancer, with the majority of these infections being caused by a single Candida species. Studies of multiple‐species candidemia (MSC) have rarely been reported.

METHODS

The authors identified 33 patients with cancer who had candidemia (diagnosed between 1993 and 2000) caused by more than 1 Candida species. This group of 33 patients was compared with a control group of 66 patients with cancer who had C. albicans candidemia that arose soon before or soon after each case of MSC that was investigated in the current study.

RESULTS

Patients with MSC, compared with control patients, were more likely to have leukemia (33% vs. 8%; P = 0.001), to have had prolonged neutropenia before the onset of their infection (mean ± standard deviation, 10 ± 17 days vs. 3 ± 6 days; P = 0.02), and to have received chemotherapy within 1 month before their infection (42% vs. 18%; P = 0.01). Patients with MSC also had higher Acute Physiology and Chronic Health Evaluation II scores at the onset of infection (score ≥ 16, 45% vs. 26%; P = 0.05) and were more likely to have received previous antifungal prophylaxis compared with patients who had candidemia caused by C. albicans (33% vs. 11%; P = 0.006). The response of C. albicans candidemia to single‐agent antifungal therapy was significantly better than that of MSC (69% vs. 35% P = 0.004).

CONCLUSIONS

In patients with cancer, MSC was more likely to occur as breakthrough candidemia, predominantly in those with leukemia and prolonged neutropenia, and was associated with suboptimal responses to single‐agent antifungal therapy. Cancer 2004. © 2004 American Cancer Society.
Immunohistochemical visualization of corticotropin‐releasing factor type 1 (CRF1) receptors in monkey brain
Authors: Kostich Walter A. , Grzanna Reinhard , Lu Nick Z. , Largent Brian L.
Published: August 2004

Corticotropin‐releasing factor receptor type 1, CRF1, plays a prominent role in the hypothalamic‐pituitary‐adrenal (HPA) axis and is implicated in the autonomic and behavioral responses to stress. Dysregulation of the CRF system may underlie the pathophysiology of several disorders, including depression and anxiety. The distribution of CRF1 mRNA and CRF1 specific ligand binding has been reported by multiple groups in rodents using in situ hybridization and receptor autoradiography, respectively. More recently, somewhat conflicting rodent anti‐CRF1 immunohistochemical studies were reported. In this study we report the generation of an antihuman CRF1 antiserum and provide the first immunohistochemical description of CRF1 distribution in a primate brain, that of the rhesus monkey. The specificity of anti‐CRF‐R1 antiserum R221 was demonstrated using transfected hCRF1‐expressing HEK 293 cells and rhesus monkey pituitary. CRF1‐immunoreactive neurons were widespread in the rhesus brain. CRF1 staining was associated with neuronal cell bodies and dendrites and was primarily intracellular, suggesting a high rate of receptor turnover or receptor sequestration. Anti‐CRF1 immunoreactivity was most abundant in pituitary, cerebellum, and in portions of brain stem associated with sensorimotor function. CRF1 staining was also observed in cerebral cortex, basal forebrain, portions of the basal ganglia, and thalamus. Staining was relatively low in prefrontal cortex and in limbic areas, which may reflect masking of the N‐terminal epitope. The distribution of CRF1 immunoreactivity is suggestive of roles in attentional processing as well as the processing of motor and sensory information. J. Comp. Neurol. 478:111–125, 2004. © 2004 Wiley‐Liss, Inc.
Regulation of GABA transporter mRNA and protein after photothrombotic infarct in rat brain
Authors: Frahm Christiane , Haupt Corinna , Weinandy Franziska , Siegel Gabriele , Bruehl Claus , Witte Otto W.
Published: August 2004

Animal models of focal ischemic infarcts reveal an impaired GABAergic (γ‐aminobutyric acid) neurotransmission. GABA, the main inhibitory neurotransmitter, is primarily taken up by specific sodium‐dependent transporters. As these transporters play a crucial role in maintaining levels of GABA concentration, they may be functionally involved in ischemic processes. We investigated whether the mRNA and protein expression of GAT‐1, the dominant neuronal GABA transporter, is altered after cortical infarct induced by photothrombosis in Wistar rats. In situ hybridization was performed to analyze GAT‐1 mRNA‐positive cells in cortical brain regions and the hippocampus. The lesion dramatically raised the number of GABA transporter mRNA‐expressing cells in all investigated cortical regions. Double‐labeling studies with a general neuronal marker and a marker for astrocytes revealed that cells expressing GAT‐1 mRNA after photothrombosis are neurons. The mRNA expression pattern of all hippocampal subfields remained unchanged. In contrast, cortical GAT‐1 protein density was only slightly affected and surprisingly in the opposite way. In the primary and secondary somatosensory cortex, density values were significantly reduced. Immunoreactivity was not altered in all investigated hippocampal areas. We found a marked discordance between the increased number of cells expressing GAT‐1 mRNA in the cortex and the reduced tissue GAT‐1 protein content. Focal brain ischemia obviously triggers mechanisms that interfere with GAT‐1 transcriptional regulation and protein synthesis or turnover. J. Comp. Neurol. 478:176–188, 2004. © 2004 Wiley‐Liss, Inc.
Remodeling of a larval skeletal muscle motoneuron to drive the posterior cardiac pacemaker in the adult moth, Manduca sexta
Authors: Dulcis Davide , Levine Richard B.
Published: August 2004

During postembryonic development, a larval skeletal muscle motoneuron, MN‐1 in abdominal segments 7 and 8, becomes respecified to innervate the terminal cardiac chamber of adult Manduca sexta. Neural tracing techniques and electrophysiology were used in this study to describe the anatomical and physiological remodeling of this identified motoneuron. During metamorphosis the MN‐1 in segments 7 and 8 undergoes dendritic reorganization. Long new dendrites extend anteriorly in the terminal ganglion neuropil. Intracellular and extracellular recordings showed that broader action potentials, increased firing rate, and development of a bursting activity pattern accompany MN‐1 respecification. Cardiac mechanograms showed that MN‐1 activity bursts always correlate with the anterograde cardiac beat. Bilateral MNs‐1 fire at similar times to activate and sustain the putative cardiac pacemaker activity of the terminal chamber synergistically. After remodeling, MN‐1 output could be influenced rapidly by sensory inputs during evoked cardiac reversal. The effect is exerted by inhibition of MN‐1 firing that, in turn, causes early blockade of the anterograde beat and reversal to the retrograde direction of beat. J. Comp. Neurol. 478:126–142, 2004. © 2004 Wiley‐Liss, Inc.
Cyclotron Maser Radiation in Space and Laboratory Plasmas
Authors: Bingham R. , Kellett B. J. , Cairns R. A. , Vorgul I. , Phelps A. D. R. , Ronald K. , Speirs D.
Published: August 2004

One of the best known coherent radio emission mechanisms is the electron cyclotron maser instability. In this article we will demonstrate that electron cyclotron maser emission is directly associated with particular types of charged particle acceleration and propagation in space and laboratory plasmas. These include electron ring distributions, horseshoe or crescent shaped electron distribution functions. Planetary and stellarmagnetospheres are examples of where horseshoe or crescent shaped electron distributions can be found and astrophysical shocks produce ring shaped electron distribution functions. In the laboratory horseshoe or crescent shaped distributions are produced whenever an electron beam propagates into a stronger magnetic field region. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Progress of the Electron Kinetics in Spatial and Spatiotemporal Plasma Structures
Authors: Winkler R. , Arndt S. , Loffhagen D. , Sigeneger F. , Uhrlandt D.
Published: August 2004

A brief introduction into the progress of the analysis of the electron kinetics in spatially one‐ and two‐dimensional steady‐state plasmas and in spatiotemporal transition processes of spatially one‐dimensional plasma configurations is given. The wide spectrum of the involved kinetic problems is briefly characterized, main aspects of its kinetic studies are outlined and the progress reached in recent years is illustrated by the kinetic study and deduced results of some selected problems. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Emission Spectroscopy of Molecular Low Pressure Plasmas
Authors: Fantz U.
Published: August 2004

The diagnostic tool of optical emission spectroscopy with applications to molecular low pressure plasmas is introduced and the underlying principles for the analysis of molecular radiation are summarized. Results for rotational, vibrational and electronic population densities in electronically excited states and in the ground state of diatomic molecules such as hydrogen and nitrogen are shown. Besides molecular densities atomic densities are obtained and the relevance of opacity of resonance lines in the analysis is discussed. In more complex plasmas such as hydrocarbon plasmas, the radiation of radicals is used to determine particle densities. Here, the contribution of the dissociative excitation mechanism has to be taken into account. A simple monitoring tool for the determination of particle density ratios is emphasized based on the measurement of intensity ratios. Results are presented for plasma applications with volume processes as well as with plasma surface interaction. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Aspects of Turbulent Transport
Authors: Naulin V. , Rasmussen J. J.
Published: August 2004

Turbulence is an ubiquitous phenomenon in plasmas, which usually have large amounts of free energy available to drive turbulent velocity fluctuations. A universal property of turbulence is its abilities to mix and to transport quantities. We discuss the relationship between passive particle transport due to turbulence and the turbulent plasma transport, that is the relationship between mixing and transport. Moreover the turbulent transport is often found not to be described by a transport coefficient, as Fick's law suggests and it's probability density distribution function (PDF) is often far from Gaussianity, implying sub‐ or super‐diffusive transport. For an interchange turbulence model we discuss upgradient transport and bursty transport behavior. Finally we discuss transport PDFs. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Generation of Cluster Beams in a Plasma
Authors: Smirnov B. M.
Published: August 2004

The properties are considered of a cluster plasma that is used for generation of intense beams of metallic clusters. The cluster plasma is non‐equilibrium and nonuniform that provides a high intensity of forming cluster beams under optimal conditions. The plasma method of cluster generation is compared with standard methods. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Fine‐needle aspiration of adult small‐round‐cell tumors studied with flow cytometry
Authors: Leon Marino E. , Hou J. Steve , Galindo Lorenzo M. , Garcia Fernando U.
Published: August 2004

Immunophenotypic study is critical for the diagnosis of adult small‐round‐cell tumors (SRCTs). We describe three patients with Ewing's sarcoma/primitive neuroectodermal tumor (ES/PNET) and one patient with neuroblastoma in which flow cytometry immunophenotyping (FCI) on the fine‐needle aspirate (FNA) and bone marrow aspirate (BMA) demonstrated an abnormal population of cells that were CD45− and CD16/CD56+. Four patients with mean age of 30 years, three male and one female, clinically suspicious for a lymphoma or SRCT are described. FNA, BMA, and biopsy specimens were obtained for routine cytologic and histologic evaluation. Fresh tissue was studied by FCI. In all cases, the cytology smears showed small cells with round nuclei, slightly irregular nuclear membranes, fine chromatin, and scant cytoplasm. FCI showed CD16/56+ and CD45− neoplastic cells in all cases. In one case, 76% of these cells were CD99+. The diagnoses of ES/PNET were confirmed by immunohistochemical, ultrastructural, and cytogenetic studies. ES/PNET in FNA and BMA can be efficiently and rapidly diagnosed by combining cytologic examination with FCI using a panel including CD45, CD16/56, and CD99. Diagn. Cytopathol. 2004;31:147–154. © 2004 Wiley‐Liss, Inc.
Salivary duct carcinoma with neuroendocrine features: Report of a case with cytological and immunohistochemical study
Authors: Laforga Juan B.
Published: August 2004

We report a salivary duct carcinoma (SDC) of parotid gland in a 75‐year‐old male. Initially, it was studied by fine‐needle aspiration, which disclosed features of malignancy consistent with a high‐grade carcinoma. Histologically, the tumor showed typical features of SDC, predominantly with a solid and apocrine pattern. The aggressive behavior of this tumor was documented by facial palsy and the presence of 12 regional lymph node metastases. Immunohistochemical study showed positivity for cytokeratins (AE1/AE3), cytokeratin 7, GCDFP‐15, C‐erbB‐2, Mib‐1, topoisomerase II α, p53, and androgen receptors. Diffuse positivity with chromogranin‐A, synaptophysin, and Grimelius stains was also observed, suggesting endocrine features. Phosphotungstic acid hematoxylin, antimitochondrial antigen, progesterone and estrogen receptors, cytokeratin 20, and S‐100 stains were negative. To our knowledge, this is the first case reported of SDC exhibiting neuroendocrine differentiation. Diagn. Cytopathol. 2004;31:189–192. © 2004 Wiley‐Liss, Inc.
Influence of specimen adequacy on the diagnosis of ASCUS
Authors: Sebastião Ana P. Martins , Noronha Lúcia de , Pinheiro Diogo Lago , Collaço Luiz Martins , de Carvalho Newton Sérgio , Bleggi‐Torres Luiz F.
Published: August 2004

The impact of specimen adequacy on the diagnosis of cervical cytology is not fully understood. Virtually, the greatest impact of smear quality limitation factors is on the diagnosis of atypical squamous cells of undetermined significance (ASCUS) because this category is more susceptible to interpretation mistake due to its criteria subjectivity. This study aims to evaluate the impact of smear quality impairing factors on the diagnosis of ASCUS. The 1,507 cases of ASCUS studied were obtained from the Cervical Cancer Screening Program of Paraná (CCSPP). The cases were reviewed by expert cytopathologists and the results were correlated to the specimen adequacy. The results showed that the presence of obscuring blood impairs the correct diagnosis and leads the pathologist to overdiagnose negative smears as ASCUS. The presence of adequate endocervical sampling contributes to a higher rate of correct ASCUS diagnoses but did not influence the pathologist to over‐ or underestimate the cytological findings. Diagn. Cytopathol. 2004;31:155–158. © 2004 Wiley‐Liss, Inc.
Smokers' expectations to quit smoking
Authors: Hammar Henrik , Carlsson Fredrik
Published: August 2004

We investigate the effectiveness of different smoking policies on smokers' expectations to quit smoking using a choice experiment on a sample of smokers identified within the World Health Organization (WHO) MONICA Project. Our results indicate that restricted availability, increased cigarette prices, cessation subsidies and regulations at restaurants, bars and cafés increase the expected probability of smoking cessation. Regulations at work places do not seem to have any effect. The results also show the significant role of limited self‐control; smokers who have the intent to quit smoking are more likely to quit smoking if a stricter regulation is implemented. Further, smokers who have received advice from their children to quit smoking or who perceive the health risks as considerable, are more likely to expect to quit smoking. Copyright © 2004 John Wiley & Sons, Ltd.
Measuring the productive efficiency and clinical quality of institutional long‐term care for the elderly
Authors: Laine Juha , Linna Miika , Häkkinen Unto , Noro Anja
Published: August 2004

The authors consider the association between productive efficiency and clinical quality in institutional long‐term care for the elderly. Cross‐sectional data were collected from 122 wards in health‐centre hospitals and residential homes in Finland in 2001. Productive efficiency was measured in terms of technical efficiency, which was defined as the unit's distance from the (best practice) production frontier. The analysis employed stochastic production frontier estimation, where technical inefficiency in the production function was specified to be a function of ward characteristics and clinical quality of care. Several quality indicators based on the Resident Assessment Instrument, such as prevalence of pressure ulcers and depression with no treatment, were used in the analysis. The results did not reveal systematic association between technical efficiency and clinical quality of care. However, the prevalence of pressure ulcers, indicating poor quality of care was associated with technical efficiency, a fact which highlights the importance of including quality measures in the assessment of efficiency in long‐term care. Copyright © 2004 John Wiley & Sons, Ltd.
Influences of the absence of random assignment of bids on estimating willingness to pay using a discrete‐choice question
Authors: Takemura Shinji , Ohida Takashi , Sone Tomofumi , Fukuda Takashi , Takemura Yukie
Published: August 2004

This study examined the influences of the interaction between a bid and the respondent's characteristics due to insufficient random assignment of bids on the estimation of willingness to pay (WTP) using data from a discrete‐choice question. A contingent valuation survey of 152 examinees undergoing X‐ray testing for gastric cancer screening was conducted, and the median and mean WTP for the serum pepsinogen test were estimated using a logistic regression model to which the interaction terms between the bid and the respondent's characteristics, which included gender, age, annual income, frequency of prior use of a gastric cancer screening program, and perceived health, were added. There were remarkable differences in the estimated WTP according to whether the interaction term of annual income, to which the bids had failed to be assigned randomly and which had been positively correlated with the bid, was added in the model. It is suggested that it may be necessary to check if the bids were randomly assigned to the respondent's characteristics and, when correlations with the bid are found, to adjust their interaction effects. Copyright © 2004 John Wiley & Sons, Ltd.
The effect of the tobacco settlement and smoking bans on alcohol consumption
Authors: Picone Gabriel A. , Sloan Frank , Trogdon Justin G.
Published: August 2004

In the last few years, the price of cigarettes has increased considerably in the USA. In addition, a number of states have also imposed smoking bans. These increases in the cost and barriers to smoking have created a natural experiment to study relationships between smoking and drinking behaviors. In this study, we employ data from the first six waves of the Health and Retirement Survey (HRS) to analyze the effects of smoking bans and cigarette prices on alcohol consumption. We also test if past cigarette and alcohol consumption affect current alcohol consumption as predicted by co‐addiction models. We estimate dynamic panel models using GMM estimators. Our approach allows us to obtain consistent estimates irrespective of the number of time periods. The three main findings of this study are: (1) there is positive reinforcement effect of past cigarette consumption on current alcohol consumption, (2) smoking bans reduce alcohol consumption and (3) there is a positive effect of cigarette prices on alcohol consumption. Copyright © 2004 John Wiley & Sons, Ltd.
Tobacco initiation, cessation, and change: evidence from Vietnam
Authors: Laxminarayan Ramanan , Deolalikar Anil
Published: August 2004

Studies of the impact of tobacco prices on decisions to initiate and quit smoking have, to date, largely been restricted to developed countries. Such analyses, when set in developing countries, are complicated by the availability of a wide range of tobacco products that are nicotine substitutes for cigarettes. This study, which uses data from two rounds of the Vietnam Living Standards Survey in 1992–1993 and 1997–1998, finds evidence of substitution among tobacco products in response to changes in relative prices and points to the need for comprehensive tobacco‐control strategies that are not restricted to cigarettes alone. We find that higher cigarette prices may not necessarily encourage quitting and may only divert cigarette smokers to rustic tobacco, which is potentially as harmful to human health as cigarettes. Copyright © 2004 John Wiley & Sons, Ltd.
Accounting for misclassification error in retrospective smoking data
Authors: Kenkel Donald S. , Lillard Dean R. , Mathios Alan D.
Published: August 2004

Recent waves of major longitudinal surveys in the US and other countries include retrospective questions about the timing of smoking initiation and cessation, creating a potentially important but under‐utilized source of information on smoking behavior over the life course. In this paper, we explore the extent of, consequences of, and possible solutions to misclassification errors in models of smoking participation that use data generated from retrospective reports. In our empirical work, we exploit the fact that the National Longitudinal Survey of Youth 1979 provides both contemporaneous and retrospective information about smoking status in certain years. We compare the results from four sets of models of smoking participation. The first set of results are from baseline probit models of smoking participation from contemporaneously reported information. The second set of results are from models that are identical except that the dependent variable is based on retrospective information. The last two sets of results are from models that take a parametric approach to account for a simple form of misclassification error. Our preliminary results suggest that accounting for misclassification error is important. However, the adjusted maximum likelihood estimation approach to account for misclassification does not always perform as expected. Copyright © 2004 John Wiley & Sons, Ltd.
Bacteriophage Ø29 protein p6: an architectural protein involved in genome organization, replication and control of transcription
Authors: González‐Huici Víctor , Alcorlo Martín , Salas Margarita , Hermoso José M.
Published: August 2004

Protein p6 of B. subtilis bacteriophage Ø29 binds to DNA forming a nucleoprotein complex in which the DNA wraps a protein core forming a right‐handed superhelix, therefore restraining positive supercoiling and compacting the DNA. The protein does not specifically recognize a nucleotide sequence but rather a structural feature and it binds as a dimer through the minor groove. Protein p6 is in a monomer–dimer equilibrium that shifts to higher‐order structures at a concentration of about 1 mM. These structures are probably present in vivo as the intracellular concentration of p6 is estimated to be in this range, and in fact the effective concentration should be still higher due to the macromolecular crowding. The p6 oligomers show an elongated shape compatible with a helical structure reminiscent of the superhelical DNA of the nucleoprotein complex, therefore it was proposed that protein p6 forms a scaffold on which the DNA folds. Since protein p6 is very abundant in infected cells, enough to bind the entire viral progeny, it was proposed to have an architectural role organizing and compacting the viral genome. It has been demonstrated that protein p6 binds in vivo to most, if not all, the Ø29 genome, although with different affinity, the highest one corresponding to the genome ends. Binding to plasmidic DNA was much lower, although it increased dramatically when the negative superhelicity was decreased. Hence, protein p6 binding specificity for Ø29 DNA is based on supercoiling, providing that the Ø29 genome, although topologically constrained, has a negative superhelicity lower than that of plasmid DNA. The formation of the nucleoprotein complex has functional implications in DNA replication and the control of transcription. It activates the initiation of replication that occurs at the genome ends for which the binding affinity is highest. It represses early transcription from promoter C2, and, together with protein p4, it represses transcription from promoters A2b and A2c and activates late transcription from promoter A3; therefore, protein p6 is involved in the early to late transcription switch. Copyright © 2004 John Wiley & Sons, Ltd.
Crowding‐induced organization in cells: spontaneous alignment and sorting of filaments with physiological control points
Authors: Herzfeld Judith
Published: August 2004

Under sufficiently crowded conditions, elongated particles spontaneously align along a common axis and separate from particles with dissimilar packing parameters. Clarifying the relevance of these entropy‐driven phenomena to intact cells has required the development of theoretical approaches that tractably take into account daunting physiological complexities including the extreme crowding of the cytosol, the complex mixture of macromolecules present, the process of filament self‐assembly, and the characteristic widths, flexibilities and charges of filaments formed by different proteins. This review summarizes the approaches taken, including their validation by observations of simpler systems, and the insights that have been gained into the means by which cells can modulate and capitalize upon spontaneous ordering. Copyright © 2004 John Wiley & Sons, Ltd.
Studies of effects of macromolecular crowding and confinement on protein folding and protein stability
Authors: Ping Guanghui , Yuan Jian‐Min , Sun Zhengfei , Wei Yen
Published: August 2004

In cells, proteins execute specific tasks in crowded environments; these environments influence their stability and dynamics. Similarly, for an enzyme molecule encapsulated in an inorganic cavity as in biosensors or biocatalysts, confinement or excluded volume plays an important role in its stability and dynamics. In this article we present results of our experimental and theoretical investigations of the confinement and macromolecular crowding effects on protein. On the experimental side we study the stability of encapsulated cytochrome c against unfolding induced by the presence of denaturants, such as urea. Results show that, as the pore size in which protein is trapped is reduced, protein shows higher stability against denaturant‐induced unfolding. On the theoretical side, after reviewing our previous study of the confinement effects on the equilibrium and dynamic properties of protein using a minimalist (two‐dimensional lattice, Monte Carlo, Brownian dynamics) model, we have extended the model so that the effects of macromolecular crowding on such properties can be studied. Our simulations show that both folding and unfolding times increase with the number of crowders in solution, however, the equilibrium constant is affected such that the equilibrium is shifted towards the folded state. Furthermore, our results show that, for a fixed number of crowders as the size of crowder (or excluded volume) increases, the average size of protein at equilibrium decreases. Copyright © 2004 John Wiley & Sons, Ltd.
Protein folding and binding in confined spaces and in crowded solutions
Authors: Zhou Huan‐Xiang
Published: August 2004

Simple theoretical models are presented to illustrate the effects of spatial confinement and macromolecular crowding on the equilibria and rates of protein folding and binding. Confinement is expected to significantly stabilize the folded state, but for crowding only a marginal effect on protein stability is expected. In confinement the unfolded chain is restricted to a cage but in crowding the unfolded chain may explore different interstitial voids. Because confinement and crowding eliminate the more expanded conformations of the unfolded state, folding from the compact unfolded state is expected to speed up. Crowding will shift the binding equilibrium of proteins toward the bound state. The significant slowing down in protein diffusion by crowding, perhaps beneficial for chaperonin action, could result in a decrease in protein binding rates. Copyright © 2004 John Wiley & Sons, Ltd.
Mitogen‐activated protein kinase mediates purinergic‐enhanced nerve growth factor‐induced neurite outgrowth in PC12 cells
Authors: Behrsing Holger Peter , Vulliet P. Richard
Published: August 2004

In 1999, we reported new observations that several compounds, including ATP, enhance neurite expression in PC12 cells when coapplied with nerve growth factor (NGF). Because purinergic and NGF signaling have several potential interfaces in PC12 cells, a series of experiments was conducted to elucidate the signal mediators contributing to the enhancement. Activities of selected kinases were measured and Western blots evaluated mitogen‐activated protein kinase (MAPK) active and nonactive isoforms in lysates of the treated PC12 cells. In terms of purinergic potency, ATP and β,γ‐methylene ATP elicited the greatest neurite‐enhancing effect, whereas adenosine and α,β‐methylene ATP elicited the smallest. The effectiveness of a nonhydrolyzable analog such as β,γ‐methylene ATP indicates that a nonmetabolic process is responsible. In response to ATP, NGF, or NGF + ATP, MAPK activity (measured by 32P incorporation) was maximal within 2 hr and remained statistically elevated over control levels throughout the 24 hr monitored. At maximal 32P incorporation, MAPK activity in response to ATP, NGF, and NGF + ATP was two‐, four‐, and sixfold higher, respectively, than control values; the observed increase was qualitatively confirmed using Western blots. Short‐term inhibition experiments with protein kinase C and MAPK indicated that MAPK transduces the enhancing signal. We conclude from these experiments that ATP coapplied with NGF increases PC12 neurite expression by elevation of MAPK activity, likely by P2 receptor activation, and suggest that combination therapies with NGF and its enhancing adjunct compounds may be plausible for certain degenerative neurological disorders. © 2004 Wiley‐Liss, Inc.
A kinetic and product study of reaction of chlorine atom with CH3CH2OD
Authors: Crawford Mary A. , Li Zhuangjie , Heuerman Heidi A. , Kinscherff Douglas
Published: August 2004

The reaction of atomic chlorine with CH3CH2OD has been examined using a discharge fast flow system coupled to a mass spectrometer combined with the relative rate method (RR/DF/MS). At 298 ± 2 K, the rate constant for the Cl + CH3CH2OD reaction was determined using cyclohexane as a reference and found to be k3 = (1.13 ± 0.21) × 10−10 cm3 molecule−1 s−1. Mass spectral studies of the reaction products resulted in yields greater than 97% for the combined hydrogen abstraction at the α and β sites (3a + 3b) and less than 3% at the hydroxyl site (3c). As a calibration of the apparatus and the RR/DF/MS technique, the rate constant of the Cl + CH3CH2OH reaction was also determined using cyclohexane as the reference, and a value of k2 = (1.05 ± 0.07) × 10−10 cm3 molecule−1 s−1 was obtained at 298 ± 2 K, which was in excellent agreement with the value given in current literature. © 2004 Wiley Periodicals, Inc. Int J Chem Kinet 36: 584–590, 2004
Rate coefficients for the gas‐phase reaction of NO3radicals with selected dihydroxybenzenes
Authors: Olariu R. I. , Bejan I. , Barnes I. , Klotz B. , Becker K. H. , Wirtz K.
Published: August 2004

Using a relative kinetic technique, rate coefficients have been determined at (298 ± 2) K and atmospheric pressure for the gas‐phase reactions of the NO3radical with three vicinal dihydroxy aromatic compounds. The experiments were carried out in a 1080‐l quartz glass reactor at the Bergische Universität Wuppertal and in the European Photoreactor (EUPHORE), Valencia, Spain. The rate coefficients obtained (in units of cm3molecule−1s−1) using 2,3‐dimethyl‐2‐butene as the reference hydrocarbon werekNO3(1,2‐dihydroxybenzene) = (9.8 ± 5.0) × 10−11,kNO3(1,2‐dihydroxy‐3‐methylbenzene) = (17.2 ± 5.6) × 10−11, andkNO3(1,2‐ dihydroxy‐4‐methylbenzene) = (14.7 ± 6.5) × 10−11. This study represents the first kinetic investigation of the reactions of the NO3radical with dihydroxybenzenes. © 2004 Wiley Periodicals, Inc. Int J Chem Kinet 36: 577–583, 2004
Kinetics and mechanism of the hydrolytic disproportionation of iodine
Authors: Sebők‐Nagy Krisztina , Körtvélyesi Tamás
Published: August 2004

Kinetics of the hydrolytic disproportionation of I2

equation image

was studied by UV–VIS spectrophotometry at 298 K and at the ionic strength 0.2 M (NaClO4) in buffered solutions in the pH range 8.91–10.50 at different initial iodide concentrations. The characterization of this reaction is fundamental for modeling oscillatory and front reactions in the presence of iodine as reactant or intermediate as well as for drinking water treatment. A matrix rank analysis confirmed three absorbing species in the beginning of the reaction, whereas later assumption of two species is enough to describe the experimental data in the visible part of the spectrum. A reaction mechanism was proposed for disproportionation by using fitting/simulation with a multipurpose program package ZiTa, by simultaneous evaluation of 17,906 points in 79 experimental curves. A parameter set was suggested, which was obtained by absolute, relative, and orthogonal fittings of the experimental data. © 2004 Wiley Periodicals, Inc. Int J Chem Kinet 36: 596–602, 2004
Front Cover: Macromol. Biosci. 9/2004
Authors: López‐Franco Yolanda L. , Valdez Miguel A. , Hernández Javier , Calderón de la Barca Ana M. , Rinaudo Marguerite , Goycoolea Francisco M.
Published: August 2004

Front Cover: The photograph shows the main trunk of a Prosopis velutina tree bearing vitrified nodules of mesquite gum at the bark, a common phenomenon during springtime in the Desert of Sonora. The left top figure displays hydrophobic chromatography elution patterns of mesquite gum and gum arabic. Mesquite gum has been considered a potential substitute of gum arabic. The bottom figure shows Langmuir isotherms of whole and individual mesquite gum fractions of varying hydrophobicity forming monolayer films at the air/water interface.

Further details can be found in the Full Paper by Y. L. López‐Franco, M. A. Valdez,* J. Hernández, A. M. Calderón de la Barca, M. Rinaudo, and F. M. Goycoolea on page 865.
Hallucinations in Parkinson's disease: A follow‐up study
Authors: Doé de Maindreville Anne , Fénelon Gilles , Mahieux Florence
Published: August 2004

To study prevalence of hallucinations in patients with Parkinson's disease (PD) during a 1‐year period, and identify factors predictive of the onset of hallucinations in patients who were hallucination‐free at baseline, 141 unselected outpatients with PD were evaluated prospectively for a set of demographic, clinical, and therapeutic variables and the presence of hallucinations during the previous 3 months. Patient groups were compared with nonparametric tests, and logistic regression was applied to significant data. Follow‐up data were available for 127 patients. The hallucination prevalence rates (%) at the first and second evaluation were, respectively, 41.7 and 49.6 for hallucinations of all types (NS), 29.1 and 40.2 for minor hallucinations (i.e., presence or passage hallucinations, and illusions) (P = 0.02), 22.8 and 21.2 for formed visual hallucinations (NS), and 8.7 and 8.7 for auditory hallucinations (NS). Hallucinations rarely started or ceased during the study. The most labile forms were minor hallucinations, which developed in 20% of patients and ceased in 9%. During follow‐up, 15% of patients started to hallucinate. Three factors, all present at the first evaluation, independently predicted the onset of hallucinations in patients previously free of hallucinations at baseline (odds ratio; 95% confidence interval): severe sleep disturbances (14.3; 2.5–80.9), ocular disorders (9.1; 1.6–52.0), and a high axial motor score (5.7; 1.2–27.4). Hallucinations have a chronic course in most parkinsonian patients. Factors predicting the onset of hallucinations point to a role of extranigral brainstem involvement and a nonspecific, facilitating role of ocular disorders. © 2004 Movement Disorder Society
The absolute sign of J coupling constants determined using the order matrix calculation
Authors: Yan Jiangli , Kline Allen D. , Mo Huaping , Shapiro Michael J. , Zartler Edward R.
Published: August 2004

A novel methodology using the order matrix calculation to determine the absolute sign of spin–spin couplings based on the structure of organic compounds is presented. The sign of the residual dipolar coupling (RDC) depends on the sign of corresponding scalar spin–spin coupling constant and the sign of the RDC has a dramatic influence on the order matrix calculation. Therefore, the sign of the spin–spin coupling constant can be obtained by an order matrix calculation through the corresponding RDC. Six types of spin–spin coupling constants, including 2J(H,H), 1J(C,F), 2J(C,F), 3J(C,F), 2J(F,H) and 3J(F,H), were obtained simultaneously. Except for 3J(C,F) where the measured RDCs have very small magnitudes, the signs were determined unambiguously. Copyright © 2004 John Wiley & Sons, Ltd.
Complete assignment of 19F, 1H and 13C NMR spectra of monomers and precursors towards bridge trifluoromethylated poly(p‐phenylenevinylene)
Authors: Roche Alex J.
Published: August 2004

The complete assignment of 19F, 1H and 13C NMR spectra of 11 trifluoromethylated and four bistrifluoromethylated monomers for bridge trifluoromethylated poly(p‐phenylenevinylene) is described. The combination of one‐dimensional 19F, 1H and 13C spectra, long‐range fluorine couplings and the two‐dimensional techniques of direct and long‐range HETCOR (J = 140 and 8 Hz) permitted full resonance assignment. Copyright © 2004 John Wiley & Sons, Ltd.