bluuebunny/crossref_metadata_2025_split huggingface dataset:
Swelling behavior of poly{N‐[3‐(dimethylaminopropyl)] methacrylamide‐co‐acrylamide} hydrogels in aqueous solutions of surfactants
Authors: Çaykara Tuncer , Demiray Melike , Güven Olgun 
Published: May 2006

AbstractTemperature sensitive poly{N‐[3‐(dimethylaminopropyl)]methacrylamide‐co‐acrylamide} [P(DMAPMA‐co‐AAm)] hydrogels were prepared by the free‐radical crosslinking copolymerization of corresponding monomers in water with N,N‐methylenebisacrylamide as the crosslinker, ammonium persulfate as the initiator, and N,N,N′,N′‐tetramethylethylenediamine as the activator. The swelling equilibrium of the P(DMAPMA‐co‐AAm) hydrogels was investigated as a function of temperature in aqueous solutions of the anionic surfactant sodium dodecyl sulfate and the cationic surfactant dodecyltrimethylammonium bromide. In pure water, regardless of the amount of N,N‐methylenebisacrylamide, the P(DMAPMA‐co‐AAm) hydrogels showed a discontinuous phase transition between 30 and 36 °C. However, the transition temperature changed from discontinuous to continuous with the addition of surfactants; this was ascribed to the conversion of nonionic P(DMAPMA‐co‐AAm) hydrogels into polyelectrolyte hydrogels due to the binding of surfactants through hydrophobic interactions. Additionally, the concentrations of free sodium dodecyl sulfate and dodecyltrimethylammonium bromide ions were measured at different temperatures by conductometry, and it was found that the electric conductivity of the P(DMAPMA‐co‐AAm)–surfactant systems depended strongly on the swelling ratio; most notably, it changed drastically near the phase‐transition temperature of the P(DMAPMA‐co‐AAm) hydrogel. © 2006 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 1645–1652, 2006
Soil dissipation and biological activity of metolachlor and S‐metolachlor in five soils
Authors: Shaner Dale L , Brunk Galen , Belles David , Westra Phil , Nissen Scott 
Published: May 2006

AbstractThe resolved isomer of metolachlor, S‐metolachlor, was registered in 1997. New formulations based primarily on the S‐metolachlor isomer are more active on a gram for gram metolachlor basis than formulations based on a racemic mixture of metolachlor containing a 50:50 ratio of the R and S isomers. The labelled use rates of S‐metolachlor‐based products were reduced by 35% to give equivalent weed control to metolachlor. However, several companies have recently registered new metolachlor formulations with the same recommended use rates for weed control as S‐metolachlor. This research was done to compare the soil behaviour and the biological activity of metolachlor and S‐metolachlor in different soils under greenhouse and field conditions. Although Kd ranged from 1.6 to 6.9 across the five soils, there were no differences in the binding of metolachlor and S‐metolachlor to soil or in the rate of soil solution dissipation in a given soil. However, both greenhouse and field studies showed that S‐metolachlor was 1.4–3‐fold more active than metolachlor against Echinochloa crus‐galli (L.) Beauv. in five different soils and that S‐metolachlor was more active than metolachlor in three Colorado field locations. When the rates of metolachlor and S‐metolachlor were adjusted for S isomer concentrations in the formulations, there were no differences between the formulations in field, greenhouse or bioassay studies. Thus herbicidal activity is due to the S isomers, with the R isomers being largely inactive. Copyright © 2006 Society of Chemical Industry
Interface disorder and layer transitions in Ising thin films
Authors: Bahmad L. , Benyoussef A. 
Published: May 2006

AbstractThe disorder and layer transitions in the interface between an Ising spin‐1/2 film denoted (n ), and an Ising spin‐1 film denoted (m ), are studied using Monte Carlo simulations. The effects of both an external magnetic field, acting only on the spin‐1/2 film, and a crystal magnetic field acting only on the spin‐1 film, are studied for a fixed temperature and selected values of the coupling constant J p between the two films. It is found that for large values of the constant J p, the layers of the film (n ), as well as those of the film (m ), undergo a first order layering transition. On the other hand, the only disordered layer of the film (n ) is that one belonging to the interface films (n )/(m ), for any values of the crystal field Δ . We show the existence of a critical value of the crystal field Δ c, above which this particular layer of the film (n ) is disordered. We found that Δ c depends on the values of the constant coupling J p between the two films. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Effects of substitution of Sb for Pd in MnPd3 compound
Authors: Coldea M. , Pop V. , Neumann M. , Isnard O. , Pacurariu R. , Takács A. F. , Pascut L. G. 
Published: May 2006

AbstractX‐ray photoelectron spectroscopy, magnetization and magnetic susceptibility of MnPd3–x Sbx are reported. The substitution of Pd by Sb leads to drastic changes both in the crystallographic and electronic structure, with remarkable modifications in the magnetic properties of the investigated samples. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Magnetic and magnetotransport properties in (LaxSm1–x)2/3Sr1/3MnO3 (x = 1/3, 1/2 and 2/3) manganites
Authors: Asthana Saket , Nigam A. K. , Bahadur D. 
Published: May 2006

AbstractThe magnetic and transport properties of (Lax Sm1–x )2/3Sr1/3MnO3 (x = 1/3, 1/2 and 2/3) manganites, prepared by the citrate‐gel route, have been investigated. These compounds are found to crystallize in the orthorhombic structure. The hopping between Mn3+ and Mn4+ sites is controlled by the Mn–O–Mn bond angle. The magnetoresistance in 8.5 kOe fields varies from 15 to 25 percent over the temperature range 300 K to 80 K. The conduction mechanism can be understood by using the correlated small polaron model. The metal–insulator as well as magnetic transition temperatures are close to each other, which indicates the dominance of long‐range ferromagnetic ordering in the present system. At low temperatures, a weak ferromagnetic to antiferromagnetic transition is indicated, which could be due to competing superexchange and double exchange interactions. The charge localization at lower temperatures could be the possible explanation for increasing magnetoresistance. The maximum magnetic moment at 5 K, for all the samples is ∼3.6μ B/Mn, which is close to the 3.7μ B/Mn, as obtained by considering the Mn spins only. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Comparative study of optical spectra and electronic structures of CaMoO4 and CaWO4 crystals
Authors: Fujita M. , Itoh M. , Takagi S. , Shimizu T. , Fujita N. 
Published: May 2006

AbstractPolarized reflectivity spectra of CaMoO4 and CaWO4 single crystals have been measured up to 30 eV by using synchrotron radiation as a light source. The optical constants for a ‐ and c ‐axes are derived from the reflectivity spectra by a Kramers–Kronig analysis. A clear correspondence is found in the main structures of the optical spectra between molybdate and tungstate. It is revealed that the lowest bands peaking at 5.0 eV in CaMoO4 and at 6.0 eV in CaWO4 consisit of some fine structures with distinct dichroism. They are attributed to the joint density‐of‐states; in other words, no structures indicative of exciton transition are found at the fundamental absorption edge. From the comparison of the spectral profiles in CaMoO4 and CaWO4, the structures below 10 eV are ascribed to the transitions from the O 2p valence band to the conduction band mainly made of Mo 4d (W 5d) states, while those above 10 eV are assigned to the transitions to the Ca conduction band. The polarization dependence of the structures below 10 eV is explained well in terms of the intramolecular transition in an oxyanion complex in the scheelite crystal. The energy band structure of CaWO4 is discussed taking into account of the previous results such as the thermostimulated luminescence and the two‐photon excitation. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Blimp‐1 is expressed in human and mouse T cell subsets and leads to loss of IL‐2 production and to defective proliferation
Authors: Santner‐Nanan Brigitte , Berberich‐Siebelt Friederike , Xiao Zheng , Poser Niklas , Sennefelder Helga , Rauthe Stephan , Vallabhapurapu Duttu S. , Berberich Ingolf , Schimpl Anneliese , Kreth Hans‐Wolfgang , Nanan Ralph 
Published: May 2006

AbstractThe transcriptional repressor Blimp‐1 regulates terminal differentiation of B‐lymphocytes and myeloid cells. We now show that Blimp‐1 is also expressed in human and murine primary T lymphocytes. Blimp‐1 expression is highest in freshly isolated primary T cells with an antigen experienced phenotype. Th2 and CD4+CD25+ cells exhibited higher levels of Blimp‐1 mRNA than Th1 cells. However, ectopic expression of Blimp‐1 by retroviral transduction neither altered the frequency of IFN‐γ or IL‐4 producing cells nor did it induce suppressor activity. In non‐polarized cells, retroviral transduction of Blimp‐1 led to a marked reduction in IL‐2 secretion, to an inability to proliferate and to reduced viability. Our data suggest that Blimp‐1 is physiologically expressed in T lymphocytes during late stages of differentiation, induces down regulation of IL‐2 production and a shortened life span and might thus contribute to a limitation of T cell immune responses.
Characterizing the spatial structures of riparian plant communities in the lower reaches of the Heihe River in China using geostatistical techniques
Authors: He Zhibin , Zhao Wenzhi 
Published: May 2006

AbstractGeostatistical techniques are used to evaluate spatial characteristics of riparian plant communities that were mapped within a portion of the lower reaches of the Heihe River. The spatial structures of different plant communities were characterized using nugget, range and sill parameters of spherical or exponential model variograms. Model variograms revealed different plant communities with distinctive spatial properties that were quantified effectively by the parameters used in these models. Model variograms were fit to experimental variograms calculated from diameter at breast height and plant cover data collected for three 2,000 m × 5 m, nine 500 m × 5 m, and three 200 m × 2 m transects. The 2,000 m × 5 m transects were oriented perpendicular to the river and the other transects were located in such a way as to sample communities dominated by different plants. Riparian plant communities in the lower reaches of the Heihe River show patterns of patchiness, and the plant communities are mainly dominated by mature Populus euphratica, young P. euphratica, Tamarix chinensis, and Sophora alopecuroides. The maximum model variogram range for all communities was 55 m, suggesting that transects must be at least this long in order to be able to classify them unambiguously into recognizable communities. Experimental variograms were calculated for all plants in each of four mapped plant communities. The results show that the T. chinensis and S. alopecuroides dominated plant communities have distinctively large ranges, and the spatial structures of P. euphratica dominated plant communities show multiscale change. In the 2,000 m × 5 m transects, the spatial structures of riparian plant communities show a distinct change at the scale of 430 m, because this scale also is the scale of vegetation patchiness turnover, and at scales of more than 430 m the spatial structure of the community increases significantly. These findings confirm the potential of using high‐resolution remote sensing data and geostatistics for determining the vegetation community structures of riparian plant communities.
Tuberculosis in Healthcare Workers at a General Hospital in Mexico
Authors: Laniado-Laborín Rafael , Cabrales-Vargas Noemí 
Published: May 2006

Objective.To determine the incidence rate of tuberculosis (TB) disease among healthcare workers (HCWs) at a general hospital.Design.Retrospective analysis of TB cases among HCWs over the course of 5 years.Setting.A 140-bed general hospital in Tijuana, Mexico.Participants.All hospital employees who developed TB during the 5-year period.Results.From 1 January 1999 through 31 December 2003, 18 TB cases were diagnosed among the hospital personnel. During that period, the mean ( ± standard deviation) annual work force of the hospital was 819 ± 21.7 employees. The TB incidence rate was 439.56 cases per 100,000 employees; this rate was 10.98 times higher than the rate for the general population of the city. The TB incidence rate for physicians was 860.21 cases per 100,000 employees, that for nurses was 365.85 cases per 100,000 employees, and that for physicians in training was 1,846.15 cases per 100,000 employees. Physicians in training had a higher risk of acquiring TB than did either physicians (relative risk, 2.14 [95% confidence interval, 1.34-35.66) or nurses (relative risk, 5.04 [95% confidence interval, 3.16-83.33). Three of the HCWs with TB disease were infected with a drug-resistant strain of Mycobacterium tuberculosis, and one of the infecting strains was multidrug resistant. Asymptomatic TB infection among HCWs was not addressed during this study.Conclusions.The TB incidence rate among the HCWs at the hospital is extremely high, compared with that in the general population. The implementation of infection control measures is an urgent priority, to reduce this occupational hazard.
Screening for Tuberculosis Infection Using Whole-Blood Interferon-γ and Mantoux Testing Among Japanese Healthcare Workers
Authors: Harada Nobuyuki , Nakajima Yutsuki , Higuchi Kazue , Sekiya Yukie , Rothel Jim , Mori Toru 
Published: May 2006

Objective.To examine the hypothesis that results of the QuantiFERON-TB Gold assay (QFT-G), a whole-blood test for detection of tuberculosis infection, are more significantly related to known risk factors for tuberculosis infection in healthcare workers (HCWs) who have received bacille Calmette-Guerin vaccine than are results of the Mantoux tuberculin skin test (TST).Design.All HCWs (approximately 510) from a 370-bed general hospital in Tokyo where patients with and patients without tuberculosis are treated were invited to participate in the study. All study participants completed a questionnaire about their Mycobacterium tuberculosis infection risk factors as HCWs at the general hospital. They were then tested for LTBI by means of the QFT-G, followed by the TST. Statistical analyses were performed to compare results of each test with M. tuberculosis infection risk factors (age, length of employment in the healthcare industry, history of working with tuberculosis-positive patients in a tuberculosis ward or in the outpatient department of the hospital's tuberculosis clinic for more than 1 year, chest radiograph evidence of healed tuberculosis, history of performing bronchoscope procedures, and job classification), and for TST-positive HCWs, to compare the QFT-G result with the TST induration diameter.Results.A total of 332 HCWs (95% of whom had been vaccinated with BCG) participated in the study, and 33 had positive QFT-G results, suggesting a prevalence of LTBI of 9.9%. Of 304 HCWs who underwent TST, 283 (93.1%) had an induration diameter of 10 mm or more. Multiple logistic regression analysis revealed that positive QFT-G results were significantly associated with age and with a history of working in a tuberculosis ward or an outpatient department of a tuberculosis clinic. TST results were not correlated with any of the tuberculosis infection risk factors we evaluated.Conclusions.Positive QFT-G results were closely associated with the presence of risk factors for LTBI in a hospital setting, suggesting that the QFT-G can detect LTBI in a population composed predominately of BCG vaccinees. Because most HCWs worldwide have been vaccinated with BCG, the QFT-G offers a significant improvement over the TST in tuberculosis screening programs and minimizes un-warranted use of tuberculosis prophylaxis.
Tuberculosis in Healthcare Workers: A Molecular Epidemiologic Study in San Francisco
Authors: Ong Adrian , Rudoy Irina , Gonzalez Leah C. , Creasman Jennifer , Kawamura L. Masae , Daley Charles L. 
Published: May 2006

Objective.Healthcare workers (HCWs) are at risk of becoming infected with Mycobacterium tuberculosis through occupational exposure. To identify HCWs who became infected and developed tuberculosis as a result of their work, we studied the molecular epidemiology of tuberculosis in HCWs.Design.Eleven-year prospective cohort molecular epidemiology study.Setting.City and County of San Francisco, California.Patients.All persons reported with tuberculosis between 1993 and 2003. HCWs were identified from the San Francisco Tuberculosis Control Section's database, and mycobacterial isolates from culture-positive subjects were analyzed by IS6110-based genotyping. RESULTS. Of 2510 cases of tuberculosis reported during the study period, 31 (1.2%) occurred in HCWs: the median age of the HCWs was 37 years, and 11 (35%) were male. HCWs were more likely than non-HCWs to be younger (P= .0036), born in the United States (P= .0004), and female (P= .0003) and to not be homeless (P= .010). The rate of tuberculosis among HCWs remained constant during the study period, despite a significant decrease in the overall case rate in San Francisco. Work-related transmission was documented in at least 10 (32%) of 31 HCWs, including 4 of 8 HCWs whose isolates were part of genotypically determined clusters. Only 1 of 7 cases of tuberculosis in HCWs after 1999 was documented as being work related.Conclusions.Although most cases of tuberculosis in HCWs, as in non-HCWs, developed as a result of endogenous reactivation of latent infection, at least half of clustered cases of tuberculosis in HCWs were related to work. The number of work-related cases of tuberculosis in HCWs decreased during the study period.
Preoperative Low Molecular Weight Heparin as Venous Thromboembolism Prophylaxis in Patients at Risk for Prosthetic Infection After Knee Arthroplasty
Authors: Asensio Angel , Ramos Antonio , Múñez Elena , Vilanova José L. , Torrijos Pedro , Garcia Fernando J. 
Published: May 2006

AbstractObjective:To investigate the effect of preoperative initiation of low molecular weight heparin as prophylaxis for deep venous thrombosis in patients at risk of developing surgical-site infections after knee arthroplasty.Design:Case–control study nested in a cohort. The incidence of surgical-site infection in the cohort was calculated. With the use of data extracted from medical histories and after adjustment for other risk factors, the effect of preoperative heparinization on the risk of incisional and prosthetic infection among case-patients and control-patients (1:3 ratio) was assessed.Setting:Orthopedic department in a tertiary-care referral hospital.Patients:A cohort of 160 consecutive patients who had received prosthetic knee implants between October 1, 2001, and November 30, 2003.Results:Eighteen patients with surgical-site infections were identified, yielding an incidence of incisional and prosthetic infection of 6.9 (95% confidence interval [CI95], 3.5 to 12.0) and 4.4 (CI95,1.8 to 8.8) cases per 100 patients undergoing surgery, respectively. Surgical-site infection was associated with preoperative use of low molecular weight heparin (odds ratio [OR], 6.2 after adjustment for medical and surgical factors; CI95, 1.5 to 23). Prosthetic infection was strongly associated with preoperative use of prophylaxis (OR, undetermined [100% exposure in case-patients vs 35% exposure in control-patients];P= .002), but incisional surgical-site infection was not.Conclusion:The use of low molecular weight heparins immediately before knee arthroplasty as prophylaxis for deep venous thrombosis should be questioned because of probable increased risk of prosthetic infection.
Chylothorax as a complication of innominate vein thrombosis induced by a peripherally inserted central catheter
Authors: Wu E. T. , Takeuchi M. , Imanaka H. , Higuchi T. , Kagisaki K. 
Published: May 2006

SummaryA 5‐month‐old boy with hypoplastic left heart syndrome developed chylothorax and oedema of the left upper arm more than 2 months after recovering from a Norwood stage II operation. Venography showed occlusion of the innominate vein with abundant collaterals crossing the midline to join the right internal jugular vein. The occlusion was caused by a peripherally inserted central catheter under systemic heparinisation. This case highlights the importance of a patent venous pathway, especially in patients with a cavopulmonary connection in the upper extremities.
High concentration potassium permanganate eliminates protein and particle contamination of the reusable Classic™ laryngeal mask airway
Authors: Laupau W. , Brimacombe J. , Richards E. , Keller C. 
Published: May 2006

SummaryIn this three‐stage study, we test the hypothesis that supplementary cleaning with potassium permanganate ≥4 mg.l−1 eliminates protein and particle contamination from the reusable Classic™ laryngeal mask airway. The first stage involved supplementary cleaning of 70 1 × 1 cm segments from deliberately contaminated laryngeal mask airways using potassium permanganate at 0, 2, 4, 8, 16, 32 and 64 mg.l−1 and testing for protein staining. This showed that the lowest concentration required to eliminate protein contamination was 8 mg.l−1. The second stage involved supplementary cleaning of 50 used laryngeal mask airways with either potassium permanganate 8 mg.l−1 or saline and testing for protein staining. This showed that protein contamination was lower in the potassium permanganate group (p < 0.00001): all laryngeal mask airways in the control group and none in the potassium permanganate group were contaminated. The third stage involved scanning electron microscopic examination of 1 × 1 cm segments from three laryngeal mask airways used in the control group, three from the potassium permanganate group, plus three brand new laryngeal mask airways. The mean density of ≥1 μm surface particles was lower in the potassium permanganate 8 mg.l−1 than the control group (21 vs. 121 .cm−2, p < 0.0001) and was similar to brand new laryngeal mask airways (24 .cm−2). We conclude that supplementary cleaning with potassium permanganate 8 mg.l−1 eliminates protein deposits from reusable laryngeal mask airways and reduces particle contamination to similar levels to brand new laryngeal mask airways.