bluuebunny/crossref_metadata_2025 huggingface dataset:
Demand for private health insurance: how important is the quality gap?
Authors: Costa Joan , Garcia Jaume
Published: June 2003

Perceived quality of private and public health care, income and insurance premium are among the determinants of demand for private health insurance (PHI). In the context of a model in which individuals are expected utility maximizers, the non purchasing choice can result in consuming either public health care or private health care with full cost paid out‐of‐pocket. This paper empirically analyses the effect of the determinants of the demand for PHI on the probability of purchasing PHI by estimating a pseudo‐structural model to deal with missing data and endogeneity issues. Our findings support the hypothesis that the demand for PHI is indeed driven by the quality gap between private and public health care. As expected, PHI is a normal good and a rise in the insurance premium reduces the probability of purchasing PHI albeit displaying price elasticities smaller than one in absolute value for different groups of individuals. Copyright © 2002 John Wiley & Sons, Ltd.
Training subspecialty nurses in developing countries: Methods, outcome, and cost
Authors: Wilimas Judith A. , Donahue Nora , Chammas Georgette , Fouladi Maryam , Bowers Lynne J. , Ribeiro Raul C.
Published: June 2003

Background

As infections are controlled in developing countries, other pediatric subspeciality programs such as oncology become increasingly important. A major impediment to the development of such programs is a lack of trained nurses. Therefore, education of pediatric subspecialty nurses becomes a priority.

Procedure

We describe three models we have used for education of pediatric oncology nurses: a short series of classes or lectures with additional training of key nurses, an expanded 12 week series of classes at centers combining didactic and clinical instruction and a regional residential school offering regular 12 week courses in theory and clinical practice.

Results

Cost analysis showed that the cost per nurse trained was, respectively, $3,700; $4,350; and $5,500. Early effectiveness indicators show that retention rates are high, home institutions are satisfied, and nurses trained shared their knowledge with other nurses and improved nursing practices.

Conclusions

Programs to teach subspecialty nursing in developing countries are effective and can improve medical care. Such programs should be based on past experience and evaluated as to cost and effectiveness. Med Pediatr Oncol 2003;41:136–140. © 2003 Wiley‐Liss, Inc.
Role of radiosurgery in craniopharyngiomas: A preliminary report
Authors: Amendola Beatriz E. , Wolf Aizik , Coy Sammie R. , Amendola Marco A.
Published: June 2003

Purpose

The purpose of this retrospective review is to evaluate our experience using radiosurgery in the management of craniopharyngiomas.

Materials and Methods

Fourteen patients, 6 males and 8 females, ages ranging from 3 to 44 years of age, were treated with radiosurgery from February 1994 through December 2000 for primary or recurrent craniopharyngioma. There were two adults and 12 children. All patients were treated with the Leksell Gamma units Model U or C. The mean minimum dose was 14 Gy ranging from 11 to 20 Gy and the mean maximum dose was 29 Gy ranging from 24 to 40 Gy. Volume of treatment ranged from 0.1 to 26.5 cm3. The dose to critical structures was below 8 Gy to the optic chiasm and below 14 Gy to the brain stem. One of the 14 patients had previous conventional radiation therapy.

Results

All patients are alive and with out evidence of recurrent disease 6–86 months after treatment. Only two patients required retreatment.

Conclusions

Although craniopharyngioma is a benign tumor, its location makes even advanced microsurgical techniques difficult to perform. Radiosurgery obviates the shortcomings of surgical resection near the hypothalamic‐pituitary axis without the morbidity of open surgery. Med Pediatr Oncol 2003;41:123–127. © 2003 Wiley‐Liss, Inc.
Electronic and geometric structures of Sin– and Sin+ (n = 2–10) clusters and in comparison with Sin
Authors: Li Bao‐xing , Cao Pei‐lin , Zhou Xu‐yan
Published: June 2003

Using full‐potential linear‐muffin‐tin‐orbital molecular‐dynamics (FP‐LMTO‐MD) method, we have studied the geometric and electronic structures of ionic Si2–10 clusters. The structures we obtained include not only all the most stable structures reported previously, but also some new structures. Our calculations show that the ground state structure of negative Si8– cluster ion is a new structure with C2v, which is different from that reported before. In addition, we have also found that the ground state structure of positive Si+10 cluster ion is a tricapped pentagonal bipyramid with Cs symmetry, which has been not reported previously. As for their electronic structures, these charged silicon clusters show 0.5–2.5 eV of energy gaps between the lowest unoccupied energy level and the highest occupied energy level. The gaps for cationic silicon clusters are closer to those of their corresponding neutral clusters, but many of the gaps for the anionic clusters are not.
Orientation effects on the magnetic properties of a pair Cr6 and V6 atomic clusters embedded in bulk Fe
Authors: Alvarado‐Leyva P. G. , Dorantes‐Dávila J.
Published: June 2003

The magnetic and electronic properties of a pair Cr6 and V6 atomic clusters embedded in bulk Fe are determined by using a realistic spd‐band Hubbard‐like model. The spin density distribution is calculated self‐consistently in the unrestricted Hartree–Fock approximation. The local magnetic moments μ(i) and the density of electronic states ρi(ε) are obtained at various atoms i of the cluster and of the surrounding Fe matrix. We consider two different orientations between the clusters, or better still the axis of symmetry of the clusters: collinear (C) and non‐collinear (NC). For all the cases studied the interface magnetic coupling between cluster and matrix moments is antiparallel. The Fe moments close to the cluster are slighty reduced, and the μ(i) of Cr and V atoms at the interface are often much larger than the Cr bulk moments (e.g. μ(i) = –1.39μB for Cr6 in Fe in both orientations). We compare the results with the corresponding results for just one Cr6 and V6 atomic cluster embedded in bulk Fe.
Some universal relations between the gap and thermodynamic functions plausible for various models of superconductors
Authors: Gonczarek Ryszard , Krzyzosiak Mateusz
Published: June 2003

It is proven that there exist some universal relations between the energy gap and the differences of the thermodynamic potential, entropy, specific heat and critical magnetic field for many two‐ and three‐dimensional models of superconductivity with spin‐singlet Cooper pairs forming s or d or g etc. states. The obtained formulae make it possible to derive thermodynamic functions and, in particular, the superconducting specific heat and the critical magnetic induction in the whole temperature range 0 ≤ T ≤ Tc employing the form of Δ(T) only. The inverse formula allowing us to find Δ(T), when the temperature dependence of the specific heat difference is known, is also presented. The results are referred to some obtained within the McMillan formalism, and some remarks on the application of the present formulae to the t–J model are given.
Effects of stoichiometries on the positron distribution in Si1–x–yGexCy alloys
Authors: Soudini B. , Bensaâd Z. , Abid H. , Sehil M.
Published: June 2003

The effect of alloying on the positron distribution in Si1–x–yGexCy alloys is reported. Our computations of the thermalized positron densities are based on the independent particle method coupled with the empirical pseudopotential method to derive the positron and electron wave functions, respectively. Initial results show a clear symmetrical positron charge distribution relative to the bond centre, a quite similar situation that was found in the IV groups. Since the minimum band gaps were found to be very sensitive to the carbon as well as the germanium concentration variations, this has an immediate consequence on the positron densities, where we find a deviation from linearity. This illustrative result was an indication of the alloying effect in this system (bowing effect).
Acellular dermal allograft for vestibuloplasty—an alternative to autogenous soft tissue grafts in preprosthetic surgical procedures: A clinical report
Authors: Bhola Monish , Newell Donald H. , Hancock Everett B.
Published: June 2003

Various vestibular extension procedures have been described in the literature over the past 6 decades, including the use of free gingival grafts. An acellular dermal allograft has been used as a substitute for autogenous soft tissue grafts in root coverage procedures. This clinical report describes the use of such an allograft as a substitute for palatal donor tissue in the vestibular extension of an edentulous maxillary arch with multiple frenum attachments before fabrication of a complete denture. In this patient, healing was uneventful, and 6‐month clinical observations demonstrated an apical positioning of the mucogingival junction with an increase in vestibular depth, and the absence of multiple frenae. The acellular dermal allograft appears to be a useful substitute for autogenous palatal grafts in preprosthetic surgery. This approach has many advantages over the free gingival graft, including no donor site morbidity, unlimited availability, and better color match.
Transition from continental break‐up to punctiform seafloor spreading: How fast, symmetric and magmatic
Authors: Corti Giacomo , Van Wijk Jolante , Bonini Marco , Sokoutis Dimitrios , Cloetingh Sierd , Innocenti Fabrizio , Manetti Piero
Published: June 2003

We present a comparison between numerical and analogue models focusing on the role of inherited lithospheric structures in influencing the process of continental break‐up. Our results highlight that the presence of pre‐existing anisotropies localizes strain and favors continental break‐up and formation of a new ocean. For a fixed strain rate, the pre‐rift lithosphere configuration influences rift duration, melt production and width and symmetry of the continental margin pair. Model results show a mainly two‐phase tectonic history from continental extension to oceanization. In the first phase extension affects contemporaneously the whole rift structure, while in the second phase asthenosphere upwelling occurs into punctiform regularly‐spaced spots sequentially propagating in an extension‐orthogonal direction.
Prevalence of extra‐oesophageal manifestations in gastro‐oesophageal reflux disease: an analysis based on the ProGERD Study
Authors: Jaspersen D. , Kulig M. , Labenz J. , Leodolter A. , Lind T. , Meyer‐Sabellek W. , Vieth M. , Willich S. N. , Lindner D. , Stolte M. , Malfertheiner P.
Published: June 2003

Background and aims: Gastro‐oesophageal reflux disease (GERD) can be associated with a variety of extra‐oesophageal disorders (EED) such as chronic cough, asthma, laryngeal disorder or chest pain. The aim of the study was to estimate and compare the prevalence of EED in a population with symptomatic GERD presenting as either erosive reflux disease (ERD) or non‐erosive reflux disease (NERD).

Methods: Baseline data were collected from a prospective, multicentre, open cohort study (ProGERD) in which patients will be followed for 5 years after initial treatment with esomeprazole. Within the framework of this trial, all patients underwent gastroscopy and filled out a questionnaire designed to assess EED. The influence of potential prognostic factors on the prevalence of EED was analysed by multivariate (stepwise logistic regression) analysis.

Results: 6215 patients (3303 male, 2912 female; mean age 54 years) presenting with heartburn were included. EED was detected in 32.8% of all patients. The proportion was significantly higher (P = 0.0002) in ERD patients (34.9%) than in NERD patients (30.5%). As judged from the multivariate analysis, female gender, age, oesophagitis of LA grade C/D, duration of GERD disease greater than 1 years and smoking were significantly associated with EED. ERD patients with oesophagitis of LA grade A or B did not have a significantly higher risk of EED than patients with NERD.

Conclusions: Patients with GERD have a high probability of experiencing EED, which may be associated with a number of prognostic factors such as duration and severity of GERD. Extra‐oesophageal disorders are slightly, but statistically, more prevalent in ERD than in NERD patients.
NOD2/CARD15 gene polymorphisms and Crohn's disease in the Chinese population
Authors: Leong R. W. L. , Armuzzi A. , Ahmad T. , Wong M. L. , Tse P. , Jewell D. P. , Sung J. J. Y.
Published: June 2003

Background: Crohn's disease affects people world‐wide, but the incidence in Asia is lower than in Western countries. This difference may be due to genetic and/or environmental factors. Three single nucleotide polymorphisms (SNPs) of the NOD2/CARD15 gene have been identified to be independently associated with the development of Crohn's disease in Caucasians. Whether these SNPs are involved in the pathogenesis of Crohn's disease in the Chinese population is unknown.

Aim: To determine if NOD2/CARD15 gene polymorphisms are found in Chinese patients with Crohn's disease.

Methods: Sixty‐five consecutive Chinese Crohn's disease patients had genotyping performed using sequence‐specific PCR directed against the wild‐type and the Arg702Trp, Gly908Arg and 3020insC variants of the NOD2/CARD15 gene. Controls consisted of 63 patients with ulcerative colitis and 70 patients with dyspepsia.

Results: None of the patients with Crohn's disease had heterozygous or homozygous SNP variants. Similarly none of the ulcerative colitis or dyspeptic controls had these SNPs.

Conclusion: The three previously described SNPs associated with the development of Crohn's disease in Caucasians are not found in Chinese patients with Crohn's disease.
Therapy‐related myelodysplasia and/or acute myeloid leukaemia after autologous haematopoietic progenitor cell transplantation in a prospective single centre cohort of 221 patients
Authors: Beauchamp‐Nicoud Anne , Feneux Danielle , Bayle Chantal , Bernheim Alain , Léonard Claude , Koscielny Serge , Tchernia Gil , Bourhis Jean‐Henri
Published: June 2003

Summary. To evaluate the incidence and the predictive signs of therapy‐related myelodysplasia and/or acute myeloid leukaemia (tMDS/tAML), we undertook a prospective study over a 4‐year period of 221 patients who underwent autologous haematopoietic progenitor cell transplantation. Only seven patients (3·1%) were identified to have tMDS/tAML. Peripheral cytopenia was the first sign; diagnosis could be achieved by cytological analysis of bone marrow smears using World Health Organization criteria. All patients presented with bi‐ or trilineage dysplasia. Haematopoietic reconstitution was significantly delayed in patients progressing to tMDS/tAML compared with the control group. Typical cytogenetic abnormalities were observed in five of seven patients. The mean time interval between transplantation and cytological diagnosis, or detection of cytogenetic abnormalities, was 20·0 months and 31·2 months respectively. Pantelomeric fluorescence analysis using quantitative fluorescence in situ hybridization enabled us to make two major observations: (i) the fluorescence intensity in metaphases of all autografted patients was weak, and highly variable between tMDS patients; (ii) a drastic reduction of the telomere fluorescence intensity was observed in two patients who rapidly evolved to acute leukaemia. In conclusion, early detection of tMDS/tAML could be achieved by close follow‐up of the bone marrow repopulation, and confirmed by cytological bone marrow examination and cytogenetic study. Our results address the implication of several factors, such as the initial telomeric status, and the effect of cytogenetic abnormalities and clonal expansion on bone marrow repopulation.
An accurate model for a lead‐acid cell suitable for real‐time environments applying control volume method
Authors: Schweighofer Bernhard , Brandstätter Bernhard
Published: June 2003

The accurate simulation of battery cells is of growing interest in automotive industry especially in hybrid vehicle technology. Conventional lumped parameter models are not able to predict the battery voltage accurately. Thus models describing the physics of the battery cell are searched. In this paper a model consisting of six partial differential equations is proposed, which predicts the state of charge (SOC) and the battery voltage for given charge and discharge current densities.
Simulation of a mode stirred chamber excited by wires using the TLM method
Authors: Weinzierl Djonny , Raizer Adroaldo , Kost Arnulf , de Salvador Ferreira Golberi
Published: June 2003

This paper presents the use of transmission‐line modelling ‐ time domain (TLM‐TD) method to analyse the fields in mode stirred reverberation chambers excited by wires. It will be shown how the fields inside the chamber are distributed for a large range of excited frequencies. The work intends to develop a numerical procedure to verify the effectiveness and usefulness of the TLM method to electromagnetic compatibility problems. The numerical model presented here is based on the classical symmetrical condensed 3D node. The simulations will be compared with method of moments results obtained in available benchmark data. Some comments are made on comparisons between the two techniques.
Land contamination and urinary abnormalities: cause for concern?
Authors: Staples B , Howse M L P , Mason H , Bell G M
Published: June 2003

Aims:To determine the prevalence of proteinuira and enzymuria among a cohort of subjects exposed to hexachlorobutadiene (HCBD) in their homes and to determine whether there was a change in observed effects when exposure ceased.

Methods:Residents underwent a health check, which included a panel of urinary markers of both glomerular and tubular origin, within two months of cessation of long term exposure to HCBD and again at least 10 months after exposure ceased. Analysis of the results was performed to determine if there was any early evidence of renal effects, and to ascertain whether changes in these parameters occurred after exposure to HCBD ceased.

Results:Tubular proteinuria and enzymuria were increased in the initial health check and significantly decreased after the residents had left their homes for about 10 months. As the early renal tubular markers improved when exposure ceased it is anticipated that the long term nephrotoxic risk will be minimal, but the carcinogenic risk remains unknown.

Conclusions:Results show there was a renal effect which improved when subjects left their homes. This suggests there was a local environmental factor responsible for the observations. This is consistent with the predicted toxicological effects of HCBD from animal studies.
Work related and individual predictors for incident neck pain among office employees working with video display units
Authors: Korhonen T , Ketola R , Toivonen R , Luukkonen R , Häkkänen M , Viikari-Juntura E
Published: June 2003

Aims:To investigate work related and individual factors as predictors for incident neck pain among office employees working with video display units (VDUs).

Methods:Employees in three administrative units of a medium sized city in Finland (n = 515) received mailed questionnaires in the baseline survey in 1998 and in the follow up survey in 1999. Response rate for the baseline was 81% (n = 416); respondents who reported neck pain for less than eight days during the preceding 12 months were included into the study cohort as healthy subjects (n = 232). The follow up questionnaire 12 months later was completed by 78% (n = 180). Incident neck cases were those reporting neck pain for at least eight days during the preceding 12 months.

Results:The annual incidence of neck pain was 34.4% (95% CI 25.5 to 41.3). Poor physical work environment and poor placement of the keyboard increased the risk of neck pain. Among the individual factors, female sex was a strong predictor. Smoking showed a tendency for an increased risk of neck pain. There was an interaction between mental stress and physical exercise, those with higher mental stress and less physical exercise having especially high risk.

Conclusion:In the prevention of neck disorders in office work with a high frequency of VDU tasks, attention should be given to the work environment in general and to the more specific aspects of VDU workstation layout. Physical exercise may prevent neck disorders among sedentary employees.
Exposure to nitroaromatic explosives and health effects during disposal of military waste
Authors: Letzel S , Göen Th , Bader M , Angerer J , Kraus T
Published: June 2003

Aims:To investigate the exposure to dinitrotoluene (DNT) and trinitrotoluene (TNT) and the resulting effects in workers which occur during the disposal of military waste.

Methods:Eighty two employees from a mechanical plant in Germany were studied, of whom 51 were regularly exposed to ammunition containing TNT and DNT, 19 occasionally, and 12 not at all.

Results:Air analyses yielded maximum concentrations of 20 μg/m3for 2,4-DNT and 3250 μg/m3for 2,4,6-TNT, respectively. The maximum concentrations in the urine of workers regularly exposed amounted to 5.0 μg/l of 2,4,6-TNT, 1464.0 μg/l of 2-amino-4,6-dinitrotoluene, 6693.0 of μg/l 4-amino-2,6-dinitrotoluene, 2.1 μg/l of 2,4-DNT, 95.0 μg/l of 2,4-dinitrobenzoic acid, and 3.6 μg/l of 2,6-DNT. There was a highly significant linear correlation between the urinary concentrations of the two main metabolites of TNT, 2-amino-4,6-dinitrotoluene and 4-amino-2,6-dinitrotoluene. In 63 persons TNT or DNT or metabolite concentrations above the analytical detection limit were found in urine. These persons reported more frequently symptoms like bitter taste, burning eyes, and discoloration of the skin and hair than persons (n = 19) without detectable TNT and/or DNT exposure.

Conclusion:During the disposal of military waste containing relevant TNT and DNT, exposure can occur of occupational-medical relevance. Biological monitoring is suitable for the early detection of possible adverse effects at workplaces exposed to TNT. Protective measures should be improved, together with adequate occupational-medical surveillance of persons exposed to nitroaromatic explosives. Further studies are necessary to exclude possible long term effects.
Boundary Effects in (2+1)-Dimensional Maxwell–Chern–Simons Theory
Authors: Ferrer E. J. , de La Incera V.
Published: June 2003

The effects of the sample's boundaries in the magnetic response of the charged anyon fluid at finite temperature are investigated. For the case of an infinite-strip sample it is shown that the Meissner effect takes place at temperatures lower than the fermion energy gap ωc. The temperature dependence of the corresponding effective penetration depth is determined. At temperatures much larger than the scale ωc, a different phase is found, in which the external magnetic field penetrates the fluid.
Modified Self-Scaling Relation for the Inertial and Low Energy Containing Scales of Decaying Turbulence
Authors: Hnatich M. , Horváth D.
Published: June 2003

The limits of a new form of scaling, named Extended Self Similarity (ESS) originally suggested [R. Benzi et al., Phys. Rev.E48 (1993), 29] for the inertial, dissipation and transition scales are discussed. A modification of the ESS concept is put forward using the model of decaying turbulence at high Reynolds numbers [L. Ts. Adzhemyan et al., Czech. J. Phys.45 (1995), 517]. In this model the statistical description is simplified by the hypotheses of homogeneity, isotropy, incompressibility and self-similarity, for the power law stage of decay the presence of a single scaling length — Karman scale — is assumed within the energy containing range. The second and third structure functions of the velocity field [S2(r) and S3(r)] have been calculated using the well-known connections between the mean energy spectrum and S2(r), and between mean spectral transfer and third structure function S3(r). Both structure functions have been investigated in the inertial and low enery containing ranges, then expressed in the form involving the leading Kolmogorov's K41 asymptotics [S2(r)∝ r2/3, S3(r)∝ r] and its asymptotical corrections. These corrections allow to determine corrections to the original ESS form [Formula: see text] (for K41) and to find out the modified variant of the ESS.
Low Temperature Superfluid Response of High-Tc Superconductors
Authors: Xiang T. , Panagopoulos C. , Cooper J. R.
Published: June 2003

We have reviewed our theoretical and experimental results of the low temperature superfluid response function [Formula: see text] of high temperature superconductors (HTSC). In clean high-T c materials the in-plane superfluid density [Formula: see text] varies linearly with temperature. The slope of this linear T term is found to scale approximately with 1/T c which, according to the weak coupling BCS theory for a d-wave superconductor, implies that the gap amplitude scales approximately with T c . A T5 behavior of the out-of-plane superfluid density [Formula: see text] for clean tetragonal HTSC was predicted and observed experimentally in the single layer Hg-compound HgBa 2 CuO 4+δ. In other tetragonal high-T c compounds with relatively high anisotropy, such as Hg 2 Ba 2 Ca 2 Cu 3 O 8+δ, [Formula: see text] varies as T2 due to disorder effects. In optimally doped YBa 2 Cu 3 O 7-δ, [Formula: see text] varies linearly with temperature at low temperatures, but in underdoped YBa 2 Cu 3 O 7-δ, [Formula: see text] varies as T2 at low temperatures; these results are consistent with our theoretical calculations.
Clinical Results with Direct Thrombin Inhibitors
Authors: Nicolaides Andrew N.
Published: June 2003

Direct thrombin inhibitors inactivate thrombin without the need for antithrombin and some inactivate not only thrombin but also fibrin-bound thrombin. Hirudin has been shown to be more effective than low-dose unfractionated heparin and low molecular weight heparin for the prevention of deep vein thrombosis in high-risk orthopaedic patients. Major studies are assessing the value of direct thrombin inhibitors in patients with acute coronary syndromes. Currently, argatroban is the drug of choice in patients with heparin-induced thrombocytopenia.
Argatroban in HIT Type II and Acute Coronary Syndrome
Authors: Lewis Bruce E. , Walenga Jeanine M.
Published: June 2003

Prior to initiation of the ARG-911 and ARG-915 clinical trials, there was no optimal replacement for heparin anticoagulation in patients with heparin-induced thrombocytopenia (HIT) type II. These prospective, historical controlled studies were designed to determine the usefulness of argatroban, a direct thrombin inhibitor (DTI) that is not immunogenic and does not interact with heparin antibody, in answering this clinical need. Clinical outcomes (37-day period) for 568 argatroban-treated and 193 control patients demonstrated significantly reduced risks of the primary efficacy composite endpoint (all-cause death, all-cause amputation, new thrombosis) and the secondary endpoints (death due to thrombosis, new thrombosis) with argatroban. Argatroban patients also experienced a more rapid recovery of platelet count. Bleeding events were similar among both groups. It was concluded that argatroban anticoagulation, compared with historical controls, improves clinical outcomes without increasing bleeding risk in patients having HIT with or without thrombosis. Argatroban has since been approved in the US for both prophylaxis and treatment of thrombosis in patients with HIT. Argatroban has been used in percutaneous coronary interventions in patients with and without HIT, for peripheral vascular procedures in both large and small vessels in HIT patients, and as an adjunct to thrombolytic therapy for the treatment of AMI. Treatment success rates and the same or less bleeding was demonstrated with argatroban compared to heparin controls. These pilot studies suggest that argatroban will provide reliable anticoagulation during interventional procedures. A consistent safety profile of argatroban has been demonstrated in all studies to date. The main attributes of argatroban are its rapid onset of action, fast reversibility of its anticoagulant effect, inhibition of clot-bound thrombin, easily monitored by the aPTT and ACT and no dosage adjustment in renal-impaired individuals. These properties make argatroban a predictable and useful anticoagulant for HIT and non-HIT patients.
Antitumor Efficacy of Reticulol from Streptoverticillium against the Lung Metastasis Model B16F10 Melanoma
Authors: Lim Dae-Seog , Kwak Yi-Sub , Kim Jeong-Hwan , Ko Si-Hwan , Yoon Won-Ho , Kim Chang-Han
Published: June 2003

Reticulol was isolated from the culture broth of the strain Streptoverticillium sp. NA-4803. Recticulol (M.W. 222.2) exhibited a potent in vitro cytotoxicity against A427, a human lung tumor cell line, and B16F10, a mouse melanoma cell line. In the trypan blue staining assay for B16F10 cells, the cell viability by reticulol treatment was significantly decreased in a dose-dependent manner. The in vivo assay for the lung metastasis-blocking effect showed that reticulol injected intravenously suppressed the increase in colonies on the lung in a dose-dependent manner. In addition, the survival rate of tumor-implanted mice treated with reticulol was closely associated with its antitumoral efficacy. Reticulol administered via the peritoneum of mice showed less metastasis inhibition than that injected intravenously. To demonstrate the mechanism for inhibition of metastasis, the inhibitory effect of reticulol for matrix metalloproteinase-2 or -9 involved in melanoma metastasis was investigated; however, they were not observed on zymogram gel. In addition, the antitumor efficacy of reticulol was not associated with cell cycle arrest or apoptosis. Therefore, it was inferred that reticulol known as a phosphodiesterase inhibitor directly inhibited the growth of B16F10 melanoma, showing necrotic response. These results suggest that reticulol protects its lung metastasis via the bloodstream by inhibiting the growth of B16F10 melanoma at the cellular level.
Lipid Transfer Protein 1 Is a Possible Allergen in Arabidopsis thaliana
Authors: Chardin H. , Mayer C. , Sénéchal H. , Wal J.M. , Poncet P. , Desvaux F.X. , Peltre G.
Published: June 2003

Background: The Arabidopsis thaliana genome was recently fully sequenced, and this plant is now considered as the most useful model to study the effects of genetic engineering. The aim of the present study was to identify A. thaliana IgE-binding molecules and to localize their genes in order to evaluate the potential effect of gene insertion on the expression of IgE-binding molecules. Methods:A. thaliana flower proteins were separated by two-dimensional gel electrophoresis and transferred onto a nitrocellulose sheet. The nitrocellulose sheet was successively incubated with human sera known to contain IgE that binds to rapeseed proteins, alkaline phosphatase-conjugated goat anti-human IgE and 5-bromo-4-chloro-3-indolyl phosphate and nitroblue tetrazolium. One allergen was further identified by N-terminal amino acid microsequencing. Results: The results showed that some individuals possessed IgE that recognized numerous proteins with high molecular masses and various isoelectric points. This binding pattern strongly suggests that the epitopes recognized by these IgE could be, at least partly, sugar residues. Otherwise, out of the 10 sera that possessed IgE to Arabidopsis flower proteins, one serum strongly recognized a unique basic protein with an apparent molecular mass of around 14 kD. This protein was identified by amino acid microsequencing as the lipid transfer protein 1 (LTP1). Conclusion: We have demonstrated that A. thaliana LTP1 is IgE reactive. The gene encoding this protein is located on chromosome 2, but it has been described that family 1 of A. thaliana LTPs constitutes a multigenic family with genes located on various chromosomes.
Magnoliae Flos Induces Apoptosis of RBL-2H3 Cells via Mitochondria and Caspase
Authors: Kim Gyoo C. , Lee Soon G. , Park Bong S. , Kim Jee Y. , Song Yeon S. , Kim Jong M. , Yoo Ki S. , Huh Gi Y. , Jeong Min H. , Lim Young Jin , Kim Hyung M. , Yoo Young Hyun
Published: June 2003

Background: Magnoliae flores (MF), the buds of Magnolia denudata Desrousseaux, have been successfully used for the management of allergic diseases in Korea. The purpose of the present study was to determine their causal role in inducing apoptosis of mast cells and to verify the underlying mechanism. Methods: The viability of mast cells was assessed by the trypan blue exclusion test. Induction of apoptosis was confirmed by DNA fragmentation, nuclear staining and DNA hypoploidy. Western blotting and immunofluorescent staining were performed to study the alterations in expression level and translocation of apoptosis-related proteins. Mitochondrial membrane potential (MMP) change and cytochrome C release were assayed. Results: We present several lines of evidence indicating that MF induce apoptosis. Changes in cell morphology, generation of DNA fragmentation, cell cycle arrest, activation of caspase-3, and PARP and DFF degradations were demonstrated. The reduction of MMP and the release of cytochrome C to cytosol were also shown. Either PTP blockers, bongkrekic acid and cyclosporin A, or pancaspase inhibitors, Boc.D-fmk and zVAD-fmk, did not prevent the release of cytochrome C. Bax protein content was increased, and Bax was translocated from cytosol into mitochondria at early time points after MF treatment. Conclusions: We have demonstrated that MF induce mitochondria- and caspase-dependent mast cell apoptosis. Our observations contribute new insights to the role of MF and support the view that the clinical effect of MF may depend on their pharmacological efficacy in regulating mast cell apoptosis.
Inhibitory Activity of CX-659S, a Novel Diaminouracil Derivative, against the Rebound Phenomenon following Withdrawal of Corticosteroid Therapy for Chronic Contact Hypersensitivity Responses
Authors: Inoue Yoshifumi , Isobe Masakazu , Shiohara Tetsuo , Hayashi Hideya
Published: June 2003

Background: CX-659S, a newly discovered anti-inflammatory compound, exerts inhibitory effects on chronic contact hypersensitivity responses (CHRs) induced by repeated application with picryl chloride (PC), which is known to mimic many, if not all, events occurring within lesional skin of patients with atopic dermatitis (AD). CX-659S suppresses the expression of mRNA for interleukin (IL)-4 and IL-10 but not that for IFN-γ, and inhibits serum IgE production in a chronic CHR model. Although topical corticosteroids have been widely utilized in steroid-responsive dermatoses such as AD, their chronic use may be associated with significant side effects. In addition, a rebound phenomenonoften occurs after discontinuation of prolonged use of topical corticosteroids, with enhanced production of IgE and Th2 cell cytokines. The purpose of this study was to assess whether CX- 659S inhibits the rebound phenomenon after discontinuation of chronic treatment with prednisolone in a chronic CHR model in mice. Methods: The efficacy of CX-659S as a sequential therapeutic agent after discontinuation of chronic treatment with prednisolone was tested on PC-treated ears of BALB/c mice with chronic CHR. Effects were quantified by measurements of ear thickness, serum IgE and cytokine mRNA expression. Results: The rebound phenomenon was confirmed after discontinuation of chronic treatment with prednisolone in chronic CHR in mice, i.e. by evidence of flare thickening of the ear, enhanced expression of mRNA for IL-4 and IL-10 and increased serum IgE. Sequentially applied CX-659S suppressed these rebound phenomena with a good cosmetic result. Conclusions: CX-659S is the first promising compound with inhibitory activity on the rebound phenomenon following withdrawal of corticosteroid therapy without immunosuppression.
The Immunohistochemical Profile of the Normal Conus medullaris and Filum terminale
Authors: Cummings Thomas J. , George Timothy M.
Published: June 2003

Background: The embryopathy underlying tethering of the filum terminale is poorly understood. Few studies have detailed the normal immunohistochemical profile of the distal spinal cord. Knowledge of normal filum development is the foundation upon which to compare tissues obtained from diseased fila in patients with tethered cord syndrome. Aims: Ten distal spinal cords containing morphologically normal conus medullaris and filum terminale were obtained at autopsy from patients with no clinical evidence of tethered cord syndrome. All were immunostained with caudal neural tube developmental markers H4C4, VIN-IS-53, AC4, FP3 and NOT1, and a panel of mature neuroglial, neural crest, epithelial and mesenchymal markers. Results: H4C4 marked ventral white matter and periventricular gray matter in the conus and showed rare reactivity in neuroglial tissue of the filum. VIN-IS-53 marked ependyma, cell bodies and dorsal white matter in the conus and strongly marked neuroglial tissue in the filum. AC4 marked neuronal cell bodies and white matter in the dorsal conus and strongly marked neuroglial tissue in the filum. FP3 and NOT1 marked neuronal cell bodies of the conus and were typically negative in the filum except for rare neuronal cell bodies. NOT1 also marked ependyma in the conus and filum. Glial fibrillary acidic protein, synaptophysin, neurofilament protein and epithelial membrane antigen showed expected reactivity in neuroglial elements of the filum and conus. No staining was seen in neuroglial tissue for CAM5.2, smooth muscle actin, myoglobin, desmin, HMB45 or HAM56. Conclusions: The immunoprofile of the normal conus medullaris and filum terminale was defined with a panel of developmental caudal neural tube markers and a panel of mature markers specific for neuroglial, epithelial and mesenchymal tissues.
Identifying Novel Helix–Loop–Helix Genes in Caenorhabditis elegans through a Classroom Demonstration of Functional Genomics
Authors: Griffin Vernetta , McMiller Tracee , Jones Erika , Johnson Casonya M.
Published: June 2003

A 14-week, undergraduate-level Genetics and Population Biology course at Morgan State University was modified to include a demonstration of functional genomics in the research laboratory. Students performed a rudimentary sequence analysis of the Caenorhabditis elegans genome and further characterized three sequences that were predicted to encode helix–loop–helix proteins. Students then used reverse transcription–polymerase chain reaction to determine which of the three genes is normally expressed in C. elegans. At the end of this laboratory activity, students were 1) to demonstrate a rudimentary knowledge of bioinformatics, including the ability to differentiate between“ having” a gene and “expressing” a gene, and 2) to understand basic approaches to functional genomics, including one specific technique for assaying for gene expression. It was also anticipated that students would increase their skills at effectively communicating their research activities through written and/or oral presentation. This article describes the laboratory activity and the assessment of the effectiveness of the activity.
Surfactant interactions with P(AM–AA–BPAM) hydrophobically modified polyelectrolytes
Authors: Ye L. , Huang Ronghua , Hoffman H.
Published: June 2003

The interactions of hydrophobically modified polyelectrolytes poly(acrylamide–sodium acrylic acid–N‐(4‐butyl)phenylacrylamide [P(AM‐AA‐BPAM)] with anionic (sodium dodecyl sulfate), cationic (cetyl trimethylammonium bromide), and nonionic (tetradecyldimethyl‐aminoxid) surfactants were studied via solution rheology, surface tension, and atomic force microscopy measurements. Viscosity measurements indicated that the intermolecular association of the polymer was greatly enhanced by the interaction with the surfactants, especially the oppositely charged surfactants with both a hydrophobic association and an electrostatic attraction. The greatest viscosity increase was realized with the addition of such oppositely charged surfactants. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 2664–2671, 2003
Prediction of the molecular‐weight dependence of mutual diffusion coefficients in polymer‐solvent systems
Authors: Vrentas J. S. , Vrentas C. M.
Published: June 2003

The ability of a proposed theory to describe the molecular weight dependence of mutual diffusion coefficients for polymer–solvent systems is examined by comparison with experimental measurements. Good agreement between experiment and theory was observed for two very different polymer molecular weights. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 2778–2779, 2003
Effects of sunshine UV irradiation on the tensile properties and structure of ultrahigh molecular weight polyethylene fiber
Authors: Huapeng Zhang  , Shi Meiwu , Zhang Jianchun , Wang Shanyuan
Published: June 2003

This study investigated sunlight‐simulated ultraviolet (UV) beam irradiation on the tensile properties and structure of ultrahigh molecular weight polyethylene (UHMWPE) fibers. The tensile results showed that after 300 h sunlight UV irradiation, the tensile properties of the UHMWPE fibers were obviously degraded. Investigation of morphology revealed that the crystallinity was slightly increased, whereas the overall orientation and molecular weight of the fibers were decreased. SEM observations indicated that the degradation process was nonuniform throughout the fiber and a change from a ductile to a brittle fracture mechanism was found after UV irradiation. DMA results showed two β‐relaxations and one α‐relaxation in the original single filament, and UV irradiation led to the increased intensity of the high‐temperature β‐relaxation and the lowered position of the low‐temperature β‐relaxation. This indicated that irradiation‐induced molecular scission and branching were located primarily in the amorphous and the interface areas of the fiber. Changes in the thermal behavior were also examined by DSC. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 2757–2763, 2003
Intrinsic viscosity dependence on polymer molecular weight and fluid temperature
Authors: Rushing T. S. , Hester R. D.
Published: June 2003

Experimental solution intrinsic viscosity responses to temperature and polymer molecular weight variations were used to test the modeling capability of a simplified intrinsic viscosity equation. The multiple linear equation contains three parameters that are related to the thermodynamic properties of a polymer solution. Simple linear regression was used to produce an intrinsic viscosity equation containing unique fitted parameters for each of three solutions. These parameters describe the polymer coil size at unperturbed conditions and the polymer coil expansion capabilities of the solvent as a function of fluid temperature and molecular weight. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 2831–2835, 2003
Radiation and conduction heat transfer coupled with liquid water transfer, moisture sorption, and condensation in porous polymer materials
Authors: Wang Z. , Li Y. , Zhu Q. Y. , Luo Z. X.
Published: June 2003

A new one‐dimensional mathematical model to simulate the complex coupled heat and moisture transfer in porous polymer materials is presented. The new model takes into account effects of multiple involved processes such as radiation and conduction heat transfer, liquid capillary action, moisture sorption, and condensation. The technique of volume of fraction (VOF) is used to model the dynamic distribution of moisture in different phases, that is, vapor and liquid. The finite volume method (FVM) is used to develop the numerical computational scheme to solve the model. The temperature change on the fabric surface derived from the computational results of the model is compared with experimental measurements with reasonable agreement between the two. Further numerical simulations were carried out to investigate the complex interactions and coupling effects among the various heat and moisture‐transfer processes involved. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 2780–2790, 2003
Synthesis, characterization, and electro‐optical properties of a soluble conjugated polymer containing an oxadiazole unit in the main chain
Authors: Zhang Su‐Yang , Kong Fan , Sun Rong , Yuan Ren‐Kuan , Jiang Xi‐Qun , Yang Chang‐Zheng
Published: June 2003

A novel copolymer, poly{[2,5‐diphenylene‐1,3,4‐oxadiazole‐vinylene]‐alt‐[2‐methoxy‐5‐(2‐ethylhexyloxy)‐1,4‐phenylenevinylene]}(MEH‐OPPV) containing a high‐electron‐affinity unit of aromatic oxadiazole in the main chain is synthesized through the Wittig condensation reaction. The obtained copolymer is easily soluble in conventional organic solvents. The structure of the copolymer was characterized by Fourier transform infrared, 1H nuclear magnetic resonance, thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and ultraviolet‐visible and photoluminescence spectroscopy. The TGA result indicates that the copolymer has very high thermal stability (stable up to 310°C in nitrogen), while DSC investigation demonstrates that the glass transition temperature (Tg) is 143°C, which might be a merit for the long‐life operation of light‐emitting devices. The absorption spectrum of film sample of the copolymer reveals two peaks at 310 and 370 nm, respectively, and the edge absorption corresponds to a band gap of 2.46 eV. A single‐layer light‐emitting diode device ITO/MEH‐OPPV/Al is successfully fabricated. The device emits visible yellowish‐green light above the bias voltage of 4.0 V under ambient condition. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 2618–2623, 2003
Graft copolymerization of methyl methacrylate onto gelatin using KMnO4‐H2SO4 redox system
Authors: Keleş Havva , Saçak Mehmet
Published: June 2003

The graft copolymerization of methyl methacrylate onto gelatin was studied using KMnO4‐H2SO4 redox system. The maximum graft yield of 64.5% was obtained at the potassium permanganate concentration of 2.00 × 10−3 mol/L and the optimum temperature of 50°C. Activation energy was calculated as 18.6 kcal/mol at the temperature interval of 40–70°C. The results of the thermogravimetric analysis showed that the degradation temperature of gelatin increased as a result of grafting. Moreover, some changes in the properties of methyl methacrylate‐grafted samples were also observed. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 2836–2844, 2003
Physical and mechanical properties of photopolymerized SBS–methacrylic monomer systems
Authors: Mateo J. L. , Calvo M. , Bosch P.
Published: June 2003

An exploratory study on physical and mechanical properties—transmittance, pendulum hardness, dynamic‐mechanical, and tensile—of photopolymerized styrene–butadiene–styrene block copolymer (SBS)–methacrylic monomer systems at different compositions was carried out. The insoluble and crosslinked polymerized systems prepared exhibit a high transmittance along the visible light region and retain the regular structure corresponding to the matrix (SBS), that is, the dynamic‐mechanical spectra show the two peaks corresponding to the PS and PB phases in the tan δ–temperature plot. Trapped radicals remain in the photopoymerized SBS–methacrylic monomer (tetra or hexafunctional) system, so when these systems are heated above their vitreous transition temperature, a postpolymerization reaction is produced that gives rise to an increase of both the crosslinking density and the storage modulus. The modulus and ultimate tensile strength of the polymerized SBS–hexanediol dimethacrylate (HDDMA) systems increase with increasing initial proportions of the dimethacrylate monomer; on the contrary, the percent elongation at break and toughness decrease with increasing proportions of initial dimethacrylate monomer. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 2857–2864, 2003