bluuebunny/crossref_metadata_2025 huggingface dataset:
A new neural network‐based model for hysteretic behavior of materials
Authors: Yun Gun Jin , Ghaboussi Jamshid , Elnashai Amr S.
Published: May 2007

Cyclic behavior of materials is complex and difficult to model. A combination of hardening rules in classical plasticity is one possibility for modeling this complex material behavior. Neural network (NN) constitutive models have been shown in the past to have the capability of modeling complex material behavior directly from the results of material tests. In this paper, we propose a novel approach for NN‐based modeling of the cyclic behavior of materials. The proposed NN material model uses new internal variables that facilitate the learning of the hysteretic behavior of materials. The same approach can also be used in modeling of the hysteretic behavior of structural systems or structural components under cyclic loadings. The proposed model is shown to be superior to the earlier versions of NN material models. Although the earlier versions of the NN material models were effective in capturing the multi‐axial material behavior, they were only tested under cyclic uni‐axial state of stress. The proposed NN material model is capable of learning the hysteretic behavior of materials under even non‐uniform stress state in multi‐dimensional stress space. The performance of the proposed model is demonstrated through a series of examples using actual experimental data and simulated testing data. Copyright © 2007 John Wiley & Sons, Ltd.
Preparation and characterization of polytetrafluoroethylene‐polyacrylate core–shell nanoparticles
Authors: Cui Xuejun , Zhong Shuangling , Zhang Haitao , Gu Qiang , Li Junfeng , Wang Hongyan
Published: May 2007

Polytetrafluoroethylene (PTFE)‐polyacrylate core–shell nanoparticles were produced by using PTFE micropowder and acrylate via seeded emulsion polymerization in the presence of fluorosurfactant. The properties of emulsion under various polymerization conditions were investigated and optimized. The chemical composition of the PTFE‐polyacrylate nanoparticles was characterized by Fourier‐transform infrared spectrometry (FTIR). The particle size and core–shell structure of the resulting PTFE‐polyacrylate nanoparticles were confirmed by transmission electron microscopy (TEM). Wettability of the PTFE‐polyacrylate core–shell particles was higher than the pristine PTFE. The formation of this kind of PTFE‐polyacrylate core–shell nanoparticles could improve the compatibility of PTFE with other materials because PTFE is covered by polyacrylate shell, which make them promising in various fields. Copyright © 2007 John Wiley & Sons, Ltd.
Photo‐stabilization of EPDM–clay nanocomposites: effect of antioxidant on the preparation and durability
Authors: Lonkar Sunil P. , Kumar A. Pratheep , Singh Raj Pal
Published: May 2007

The present study is to examine the photo‐stabilization effect of an antioxidant on the photo‐oxidation of ethylene‐propylene‐diene monomer (EPDM)–clay nanocomposites. During the preparation of EPDM–clay nanocomposites via melt processing antioxidants are usually incorporated along with clay, which allows phenolic antioxidant molecules to get adsorbed onto acidic clay platelets and their interaction with metallic impurities reduces the stabilizing efficiency of the antioxidant. The nanocomposites were obtained by solution dispersion followed by melt compounding of EPDM and organophilic montmorillonite (OMMT). The samples were characterized by conventional tools such as X‐ray diffraction (XRD), Fourier Transform Infra Red (FT‐IR) spectroscopy, and thermo‐gravimetric analysis (TGA). It was found, upon photo‐irradiation (λ > 290 nm) studies by following the changes in functional groups and surface morphology, that photo‐degradation was lowered by the antioxidant and the efficiency of the antioxidant could be improved by initial incorporation of antioxidant in the EPDM matrix. In EPDM–clay nanocomposites, a stabilizing activity of the antioxidant was observed above some threshold concentration of the antioxidant. The relationship between the nanoclay reinforcement and stabilizing efficiency in terms of photo‐oxidation and surface morphology for their applicability are discussed. The methodology adopted for this study is also justified through our observation. Copyright © 2007 John Wiley & Sons, Ltd.
Drug related problems with Antiparkinsonian agents: consumer Internet reports versus published data
Authors: Schröder Sabrina , Zöllner York Francis , Schaefer Marion
Published: May 2007

Purpose

There is currently a lack of detailed information concerning drug related problems in the outpatient treatment of Parkinson's disease.

Methods

Problems associated with drug treatment communicated anonymously in Parkinson's disease online forums were therefore retrospectively searched and documented for 1 year.

Results

Based on postings concerning 12 drugs for the treatment of Parkinson's disease, a total of 238 drug related problems were identified and categorised using the Problem Intervention Documentation (PI‐Doc). Of these, 153 were adverse drug reactions. Adverse drug reactions associated with the skin were relatively common, but central effects such as cognitive or psychiatric changes, effects on the sleep/waking system and other problems like headache and dizziness accounted for the highest percentage of adverse events. A comparison with data from scientific literature revealed a number of differences. This means that an analysis of online forums detected a number of drug related problems that were otherwise largely invisible. These were mainly associated with the qualitative aspects of treatment such as medication handling, dosage and individual problems concerning adverse events. In addition, the described method of identifying and classifying drug related problems in Internet forums may also be seen as a contribution to the international discussion about consumer reports and pharmacovigilance. The information about adverse drug reactions given by Internet users can be seen as a valuable adjunct to clinical trial data and as being very timely with regard to the event itself.

Conclusion

Online forums may be considered as a suitable source of observational information to complement data from randomised clinical trials. Copyright © 2007 John Wiley & Sons, Ltd.
Use of anxiolytic or hypnotic drugs and total mortality in a general middle‐aged population
Authors: Hausken Anne Margrethe , Skurtveit Svetlana , Tverdal Aage
Published: May 2007

Purpose

The aim of the study was to evaluate the effect of the consumption of anxiolytic or hypnotic drugs on total mortality in a general population.

Methods

We followed a cohort of 7225 men and 7726 women aged 40–42 years who underwent health surveys in 1985–1989 in two Norwegian counties, with respect to deaths. Mean follow‐up period was 18 years. The subjects were categorised according to frequency of anxiolytic or hypnotic drug use during the last month: daily, every week, less than every week and not used during the last month.

Results

The proportion of anxiolytic or hypnotic drug users was 6.6% among men and 16.2% among women. Altogether 402 men and 290 women died. There was an increase in risk of death with an increase in frequency of use. Crude hazard ratios for men and women daily using anxiolytics or hypnotics were 3.1 (95%CI 2.0, 4.8) and 2.7 (1.9, 4.0), respectively, as compared with non‐users last month. After adjusting painkiller use and smoking the hazard ratios were lowered, being 2.4 (1.5–4.0) (men) and 2.1 (1.4–3.2) (women). After additional adjustments for other possible confounders the hazard ratios were further attenuated to 1.5 (0.9–2.7) for men and 1.7 (1.1–2.6) for women.

Conclusions

Daily users of anxiolytic or hypnotic drugs in our study showed higher crude mortality than non‐users. However, after adjusting lifestyle and socio‐economic variables the difference was markedly reduced suggesting that the remaining excess mortality is due to residual confounding. Copyright © 2007 John Wiley & Sons, Ltd.
Low dielectric constant nanocomposite thin films based on silica nanoparticle and organic thermosets
Authors: Lin Qinghuang , Cohen Stephen A. , Gignac Lynne , Herbst Brian , Klaus David , Simonyi Eva , Hedrick Jeffrey , Warlaumont John , Lee Hae‐Jeong , Wu Wen‐li
Published: May 2007

Low dielectric constant (low‐k) nanocomposite thin films have been prepared by spin coating and thermal cure of solution mixtures of one of two organic low‐k thermoset prepolymers and a silica nanoparticle with an average diameter of about 8 nm. The electrical, the mechanical, and the thermomechanical properties of these low‐k nanocomposite thin films have been characterized with 4‐point probe electrical measurements, nanoindentation measurements with an atomic force microscope, and specular X‐ray reflectivity. Addition of the silica nanoparticle to the low‐k organic thermosets enhances both the modulus and the hardness and reduces the coefficient of thermal expansion of the resultant nanocomposite thin films. The enhancements in the modulus of the nanocomposite thin films are less than those predicted by the Halpin‐Tsai equations, presumably due to the relatively poor interfacial adhesion and/or the aggregation of the hydrophilic silica nanoparticles in the hydrophobic organic thermoset matrices. The addition of the silica nanoparticle to the low‐k organic thermoset matrices increases the relative dielectric constant of the resultant nanocomposite thin films. The relative dielectric constant of the nanocomposite thin films has been found to agree fairly well with an additive formula based on the Debye equation. © 2007 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 45: 1482–1493, 2007
Finite element method parametric study on scratch behavior of polymers
Authors: Jiang H. , Lim G. T. , Reddy J. N. , Whitcomb J. D. , Sue H.‐J.
Published: May 2007

Parametric studies were performed using finite element analysis (FEA) to learn how material and surface properties of polypropylene (PP) affect scratch behavior. Three‐dimensional FEA modeling of scratching on a PP substrate with a spherical‐tipped indenter is presented. Three different loading conditions, that is constant scratch depth, constant normal load, and linearly increasing normal load, are adopted for this parametric study. From the FEA findings, it is learned that Poisson's ratio has a negligible effect on scratch performance, whereas raising the coefficient of adhesive friction induces a significantly larger residual scratch depth and tangential force on the scratch tip. Increasing the Young's modulus of a material does not necessarily improve its overall scratch performance. On the other hand, modifying the yield stress of a material has a major impact on scratch resistance as a higher yield stress reduces the residual scratch depth. From this numerical effort, it is concluded that the yield stress and coefficient of adhesive friction are the most critical parameters to influence the scratch performance of a material. Analyses also suggest that the general trend in the parametric effect of the above four parameters on scratch behavior is independent of the applied normal load level. © 2007 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 45: 1435–1447, 2007
Antiinflammatory activity of an herbal preparation (HemoHIM) in rats
Authors: Jo Sung Kee , Lee Hae June , Kim Se Ra , Kim Jong Choon , Bae Chun Sik , Jung Uhee , Park Hae Ran , Jang Jong Sik , Kim Sung Ho
Published: May 2007

This study evaluated a new herbal preparation, HemoHIM, for its antiinflammatory activity against carrageenan‐induced edema, the formation of granulation tissues by cotton pellet and experimental colitis by 2,4,6‐trinitrobenzene sulfonic acid (TNBS). The HemoHIM was prepared by adding its ethanol‐insoluble polysaccharide fraction to the total water extract of Angelica Radix, Cnidii Rhizoma and Paeonia Radix. The preparation (4 mg of solids/mL of drinking water, p.o., 50–100 mg/kg of body weight, i.p.) produced a dose‐related inhibition of carrageenan‐induced paw edema and cotton pellet‐induced granuloma in rats. In addition, HemoHIM also reduced the degree of TNBS‐induced colitis and improved the gross and histological changes such as thickening, dilatation, ulceration, and infiltration by polymorphonuclear leukocytes and multiple erosive lesions. These results demonstrate that the HemoHIM has a potent antiinflammatory effect. Copyright © 2007 John Wiley & Sons, Ltd.
Antitumor activity of crude polysaccharides isolated from Solanum nigrum Linne on U14 cervical carcinoma bearing mice
Authors: Li Jian , Li Qingwang , Feng Tao , Zhang Tao , Li Kun , Zhao Rui , Han Zengsheng , Gao Dawei
Published: May 2007

Solanum nigrum Linne (SNL) has been used in traditional Chinese medicine for centuries because of its diuretic and antipyretic effects. The present study examined the effect of the crude polysaccharides isolated from Solanum nigrum Linne (SNL‐P) on tumor growth. SNL‐P had a significant growth inhibition effect on cervical cancer (U14) of tumor‐bearing mice. Further analysis of the tumor inhibition mechanism indicated that the number of apoptotic tumor cells increased significantly, the expression of Bax increased and the expression of Bcl‐2 and mutant p53 decreased dramatically in cervical cancer sections after oral administration of SNL‐P for 12 days. Moreover, SNL‐P treatment decreased the level of blood serum TNF‐α. These results indicated that the tumor growth inhibition of SNL‐P administration might correlate with the reduction of TNF‐α level of blood serum, which resulted in a massive necrosis in tumor tissues and the up‐regulation of Bax and down‐regulation of Bcl‐2 and mutant p53 gene expression, which triggered apoptosis in tumor cells. These findings demonstrated that the SNL‐P is a potential antitumor agent. Copyright © 2007 John Wiley & Sons, Ltd.
Determination of 30 elements in colorectal biopsies by sector field inductively coupled plasma mass spectrometry: method development and preliminary baseline levels
Authors: Bocca Beatrice , Lamazza Antonella , Pino Anna , De Masi Ercole , Iacomino Maura , Mattei Daniela , Rahimi Siavash , Fiori Enrico , Schillaci Alberto , Alimonti Alessandro , Forte Giovanni
Published: May 2007

An analytical procedure applicable to restricted sample sizes was developed and applied to the analysis of 30 chemical elements in colorectal biopsies of healthy patients. Acidic microwave digestion processed ≤10 mg of tissue at 80°C in 15‐mL polystyrene liners. The digests were diluted to a volume of 2 mL with high‐purity water and directly analyzed by sector field inductively coupled plasma mass spectrometry without further specimen handling. A careful selection of isotopes and instrumental resolution permitted the quantification in a single analytical sequence both of the elements present at parts per trillion and of those at parts per million. The accuracy calculated on BCR 184 ranged from 93.3–110%, the recoveries of the biopsy material was in the range 95.2–105%, the precision was <10%, and the blank levels were much below those expected in biopsy samples. The metal concentrations (on a dry‐weight basis) in colorectal normal tissue showed a large range of variation: Ag, Au, Be, Bi, Co, Li, Sb, Tl, V, W and Zr were below 50 ng g−1; As, Ba, Cd, Cr, Cs, Hg, Mo, Ni, Pb, Se and Sn were distributed from 100 to 500 ng g−1; Al, Cu, Fe, Mn, Sr and Zn were from a few µg g−1 to 100 µg g−1; and Ca and Mg were at a level of 1000 µg g−1. These data represent the first attempt to achieve an elemental profile in the colorectal mucosa of healthy patients as baseline level measurements for studies focused on the imbalance of chemical elements in diseased mucosa. Copyright © 2007 John Wiley & Sons, Ltd.
Characterization by high‐performance liquid chromatography/electrospray ionization quadrupole time‐of‐flight mass spectrometry of the lipid fraction of Spirulina platensis pressurized ethanol extract
Authors: Herrero Miguel , Vicente María J. , Cifuentes Alejandro , Ibáñez Elena
Published: May 2007

Microalgae have been suggested as a potential source for new functional ingredients, making possible the development of new functional foods from natural origin. Among the natural ingredients, polyunsaturated fatty acids (PUFAs) have generally been identified as an interesting group of compounds with biological activity, mainly related to their anti‐inflammatory properties. In this regard, the use of environmentally friendly extraction procedures (e.g. pressurized liquid extraction, PLE) to obtain such natural ingredients is also becoming necessary. In this work, an exhaustive characterization of the lipid fraction of a pressurized ethanolic extract of the microalga Spirulina platensis is carried out. To achieve this objective high‐performance liquid chromatography (HPLC) coupled to quadrupole time‐of‐flight mass spectrometry (QTOF‐MS) is employed. The use of the QTOF analyzer allows the selection and isolation of precursor ions as well as providing the high efficiency, sensitivity and mass accuracy required. By means of this powerful hyphenated technique, it was possible to identify several polar lipids in an extract of S. platensis (some of them, to our knowledge, described for the first time in this work), including four free fatty acids, four monogalactosyl monoacylglycerols, three phosphatidylglycerols and two sulfoquinovosyl diacylglycerols. Copyright © 2007 John Wiley & Sons, Ltd.
Selectivity of an indolyl berberine derivative for tetrameric G‐quadruplex DNA
Authors: Gornall Karina C. , Samosorn Siritron , Talib Jihan , Bremner John B. , Beck Jennifer L.
Published: May 2007

Negative ion electrospray ionization mass spectrometry (ESI‐MS) was used to compare the binding affinities and stoichiometries of the alkaloid berberine, a 13‐substituted indolyl berberine derivative, SS14, and the chemotherapeutic agent, daunomycin, for 16‐mer double‐stranded (ds) DNA (D1 and D2) and for an 8‐mer tetrameric quadruplex, Q1 (d(TTGGGGGT)4). Under the experimental conditions presented here, ESI mass spectra of Q1 showed that the major ions were from Q1 with three ammonium ions bound in the structure. Ions from Q1 with four ammonium ions were of lower abundance. In agreement with other work, there were multiple binding sites on the dsDNA and the quadruplex for daunomycin and berberine. The binding of SS14 to both dsDNA and Q1 was less extensive. Although the binding affinity of SS14 for Q1 was modest, this compound showed a clear preference for Q1 DNA over D1 or D2 DNA. Berberine and daunomycin bound with greater affinity to both types of DNA secondary structure, with the former showing a slight preference for Q1 over D1 while the latter showed a slight preference for D1 over Q1. While at least five berberine molecules bound to Q1, this quadruplex could accommodate only two SS14 molecules. These investigations show that SS14 is a promising lead compound for drugs that may selectively bind quadruplex over duplex DNA. Copyright © 2007 John Wiley & Sons, Ltd.
Energy‐variable collision‐induced dissociation study of 1,3,5‐trisubstituted 2‐pyrazolines by electrospray mass spectrometry
Authors: Kéki Sándor , Nagy Lajos , Török János , Tóth Katalin , Lévai Albert , Zsuga Miklós
Published: May 2007

The pathways of the ([M+H]+) ions generated from electrosprayed solutions of nine 1,3,5‐trisubstituted 2‐pyrazoline derivatives were studied using energy‐variable collision‐induced dissociation (CID) and pseudo‐MS3 (in‐source CID combined with MS/MS) methods. It was shown that under CID conditions several structurally important product ions such as the 2,4‐substituted azete and 1,2‐substituted aziridine ions were formed. The compositions of the product ions were unambiguously supported by accurate mass measurement (mass accuracy was within ± 8 ppm). The fragmentation pathways of 1,3,5‐trisubstituted 2‐pyrazolines were established by means of pseudo‐MS3. It was found that a substituent at the N‐1 position greatly affects the fragmentation pathways of the 2‐pyrazoline derivatives. The 1‐acetyl‐ and 1‐propionyl‐2‐pyrazoline derivatives dissociate mainly through formation of a pyrazolium cation, while in the case of 1‐phenyl‐2‐pyrazoline derivatives product ions arising from the consecutive fragmentation of 2,4‐substituted azete and 1,2‐substituted aziridine ions dominate. Another interesting finding is the formation of a radical cation from the 2,4‐substituted azete by loss of a methyl radical. The fragmentation yield as a function of the collision energy for each of the 1,3,5‐trisubstituted 2‐pyrazolines was determined. Based on the fragmentation yield versus collision energy curves the relative fragmentation stabilities for the 1,3,5‐trisubstituted 2‐pyrazoline derivatives were also evaluated. Copyright © 2007 John Wiley & Sons, Ltd.
Investigation of unknown related substances in commercial neomycin samples with liquid chromatography/ion trap tandem mass spectrometry
Authors: Li Bo , Van Schepdael Ann , Hoogmartens Jos , Adams Erwin
Published: May 2007

The characterization of unknown impurities present in neomycin sulfate by liquid chromatography (LC) coupled with ion trap mass spectrometry (ITMS) is described. The volatile LC method was developed using an evaporative light scattering detector due to its lower investment and operating costs, easier operation and less maintenance than mass spectrometry. The method shows separation of neomycin B from seven potential related substances reported in the European Pharmacopoeia and several other unknown impurities. The unknown impurities were further investigated by coupling the developed LC method with ITMS. Their structures were deduced based on the fragmentation patterns obtained from reference substances. Four unknowns were identified as isomers of paromamine, LP‐A, neamine and LP‐B. Copyright © 2007 John Wiley & Sons, Ltd.
Genetic evolution of enterovirus 71: epidemiological and pathological implications
Authors: Bible Jon M. , Pantelidis Panagiotis , Chan Paul K. S. , Tong C. Y. William
Published: May 2007

Since its discovery in the 1970s, enterovirus 71 (EV71) has become one of the most pathogenic enterovirus serotypes causing recurrent outbreaks in different parts of the world. Three waves of outbreaks globally have been recorded over the last three decades and more recently active circulation of EV71 is evident amongst countries in South East Asia and beyond. There is evidence of a continuous evolution in its genetic make up which is likely to impact on its epidemiology and pathological potential. This review examines the molecular genetics and evolution of EV71 in relation to its epidemiological and pathological properties. A thorough understanding of the relationship between the genetic changes and the resulting host–virus interaction is essential for successful control. Copyright © 2007 John Wiley & Sons, Ltd.
Prediction of ectopic pregnancy in women with a pregnancy of unknown location
Authors: Condous G. , Van Calster B. , Kirk E. , Haider Z. , Timmerman D. , Van Huffel S. , Bourne T.
Published: May 2007

Objective

We have previously published on the use of mathematical Model M1 to predict ectopic pregnancy in women with no signs of intra‐ or extrauterine pregnancy. The aim of this study was to improve on the performance of this model for the detection of developing ectopic pregnancies in women with pregnancies of unknown location (PULs). We therefore generated and evaluated a new logistic regression model from simple hormonal data and compared it with Model M1.

Methods

Data were collected prospectively from women classified as having a PUL. These women were followed until the diagnosis was established as: a failing PUL, an intrauterine pregnancy (IUP) or an ectopic pregnancy. A multinomial logistic regression model, Model M4, was developed on 201 training cases and it was tested prospectively on another 175 women with a PUL. M4 performance was evaluated using receiver–operating characteristics (ROC) curves and compared with Model M1 based on the human chorionic gonadotropin (hCG) ratio alone.

Results

A total of 376 women with a PUL were recruited into this study: 201 in the training set (109 (54.2%) with a failing PUL, 76 (37.8%) with an IUP and 12 (6.0%) with an ectopic pregnancy; four with a persisting PUL were excluded from analysis) and 175 in the test set (94 (53.7%) with a failing PUL, 64 (36.6%) with an IUP and 15 (8.6%) with an ectopic pregnancy; two with a persisting PUL were excluded from analysis). The log serum hCG average ((hCG 0 h + hCG 48 h)/2) and the hCG ratio (hCG 48 h/hCG 0 h) were encoded as variables following multivariate analysis of the basic data. The new Model M4 contained the log of the hCG average, the hCG ratio and its quadratic effect. In the prediction of ectopic pregnancy, M4 gave an area under the ROC curve (AUC) of 0.900 and M1 gave an AUC of 0.842 (P = 0.0303).

Conclusions

Although Model M4 is superior to Model M1 when comparing the AUCs for prediction of developing ectopic pregnancies in a PUL population, in real terms this model did not result in substantially more pregnancies being classified correctly as developing ectopic pregnancies. Prospective multicenter studies are needed to assess the diagnostic performance of such models in different populations. Copyright © 2007 ISUOG. Published by John Wiley & Sons, Ltd.
Use of argentation column chromatography in the identification of fish oil fatty acids by GLC: Application to cod liver oil
Authors: Hoque M. , Ghosh Amitabha , Dutta J.
Published: May 2007

The fatty acid methyl esters from cod liver oil have been fractionated into seven fractions, depending on degree of unsaturation, by a silver nitratetreated silicic acid column. The fractions have been analyzed by gas liquid chromatography and the components identified by usual techniques.
Application of ternary equilibrium data to the production of fish protein concentrate
Authors: McPhee A. D. , Dubrow D. L.
Published: May 2007

Standard chemical engineering techniques were applied to ternary equilibria data obtained from laboratory studies for the systems water‐isopropyl alcohol‐menhaden oil and water‐ethanol‐menhaden oil to obtain information for development and operation of a fish protein concentrate process. Theoretical minimum solvent ratios, the required number of theoretical stages, stage efficiency, effect of excess water in the solvent and the effect of temperature of extraction are reported. A comparison of the solvent, isopropyl alcohol (IPA) and ethanol, at an extraction temperature of 70 C, leaves no doubt that IPA is a superior solvent for the system studied.
Alkoxylation of N‐alkyl substituted ethylenediamine
Authors: Rosenblatt W. , Stefcik A. , Bluestein C. , Kim Y. K.
Published: May 2007

The alkoxylation of a new mixture of N‐alkylethylenediamines obtained by reacting C11.5 av. chloroparaffins and ethylenediamine was studied. Ethoxylation in both laboratory glassware or Parr autoclave equipment readily produced 20 mole adducts without alkaline catalysis. The reaction was initiated by the formation of the 3 mole adduct at 160 C and subsequent addition of the alkylene oxide at 90 C. The formation of adducts with mole ratios greater than 20 required an alkaline catalyst. The preparation of propoxylate derivatives necessitated the addition of 2.5–3.0 wt % of caustic catalyst. The preparative time was minimized by operating at 185–190 C and 40–50 psi. The surfactant properties of the alkoxylates were evaluated and correlated with structures and compositions. Data on solubility, surface tension, density, refractive index, pH and foam characteristics are presented. Polyurethane foams were prepared from several of the alkoxylates.
Effect of the initial concentration of emulsifying agents on the ultracentrifugal stability of oil‐in‐water emulsions
Authors: Mittal Kashmiri L. , Vold Robert D.
Published: May 2007

The rate of loss of oil from 50% Nujol‐50% water emulsions stabilized with varying concentrations of Tween 20 or Triton X‐100, and from 50% olive oil‐50% water emulsions stabilized with sodium dodecyl sulfate (SDS), was determined by ultracentrifugation at 39,460 rpm. In all cases the ultracentrifugal stability increased with increasing initial concentration of emulsifier, although, unlike the behavior of Nujol‐water‐SDS emulsions, the rate of separation of oil decreased with time. The quantity of olive oil separated after a given time of centrifugation decreased linearly with increasing concentration of SDS, reaching zero at a concentration of SDS somewhat below the critical micelle concentration, and at adsorption of SDS corresponding to only about half the saturation capacity. The ultracentrifugal stability of Nujol emulsions with Tween 20 or Triton X‐100 continued to increase slowly with increasing concentration of emulsifier, even at concentrations far greater than the critical micelle concentration.
Observational Teamwork Assessment for Surgery (OTAS): Refinement and Application in Urological Surgery
Authors: Undre Shabnam , Sevdalis Nick , Healey Andrew N. , Darzi Ara , Vincent Charles A.
Published: May 2007

Background

Teamwork in surgical teams is at the forefront of good practice guidelines and empirical research as an important aspect of safe surgery. We have developed a comprehensive assessment for teamwork in surgery—the Observational Teamwork Assessment for Surgery (OTAS)—and we have tested it for general surgical procedures. The aim of the research reported here was to extend the assessment to urology procedures.

Methods

After refining the original assessment, we used it to observe 50 urology procedures. The OTAS comprises a procedural task checklist that assesses patient, equipment/provisions, and communication tasks as well as ratings on five team behavior constructs (communication, cooperation, coordination, leadership, and monitoring). Teamwork was assessed separately in the surgical, anesthesia, and nursing subteams in the operating theater. We also assessed the reliability of the behavioral scoring.

Results

Regarding task completion, a number of communication and equipment/provisions tasks were not routinely performed during the operations we observed. Regarding teamwork‐related behaviors, adequate reliability was obtained in the scoring of behaviors. Anesthetists and nurses obtained their lowest scores on communication. Surgeons’ scores revealed a more complex pattern. In addition to low scores on communication, surgeons’ teamwork behaviors appeared to deteriorate as the procedures were finishing.

Conclusions

Our findings suggest that OTAS is applicable to various branches of surgery. Separate assessment of the subteams in the operating theater provides useful information that can be used to build targeted teamwork training aiming to improve surgical patients’ safety and outcomes.
Prävention von Angst und Depression im Jugendalter
Authors: Balmer Katharina , Michael Tanja , Munsch Simone , Margraf Jürgen
Published: May 2007

Zusammenfassung. Der vorliegende Beitrag stellt die Re-Evaluation des schulbasierten Präventionsprogramms GO! Gesundheit und Optimismus gegen Angst und Depression in der Schweiz dar. Im Einklang mit der aktuellen Präventionsforschung werden unmittelbare Effekte bei den proximalen Variablen (z.B. Wissenszuwachs), nicht aber bei den distalen Variablen (Psychopathologie) erwartet. Das kognitiv-behavioral orientierte Programm wurde klassenweise an Schweizer Schulen durchgeführt. Explorativ wurde untersucht, ob das Programm für die Stufen Gymnasium und Weiterbildungsschule gleichermaßen geeignet ist. Es wurde ein Wartekontrollgruppe-Prä-Post-Design verwendet. Die Ergebnisse der mehrfaktoriellen Varianzanalyse zeigten sowohl im Anschluss an die Intervention sowie nach sechs Monaten einen signifikanten Wissenszuwachs bei den Gymnasiasten. Die Weiterbildungs-Schüler (WBS-Schüler, ähnlich deutschen Hauptschülern) wiesen unmittelbar nach der Programmdurchführung ebenfalls einen signifikanten Wissenszuwachs auf. Bei der Sechsmonatskatamnese waren die Wissenswerte der WBS-Schüler im Gegensatz zu denjenigen der Gymnasiasten wieder gleich tief wie vor der Programmdurchführung. Bei den Werten der Psychopathologie-Skalen, die bei der gesamten Stichprobe im Bereich Gesunder lagen, gab es zu keinem Zeitpunkt eine Veränderung. Die Werte des Fragebogens zur seelischen Gesundheit fielen bei der Sechsmonatskatamnese im Vergleich zur Baseline signifikant besser aus. Die Resultate werden in Bezug auf allgemeine Probleme der Messbarkeit von Effekten von Präventionsprogrammen diskutiert (u.a. Bodeneffekt). Da das Programm unterschiedlich ausgeprägte Verlaufseffekte bei den Wissenswerten für die verschiedenen Schulstufen aufweist, sollte die Durchführung an die jeweilige Zielgruppe besser angepasst werden.
Skalen zur Erfassung der Konstrukte des Transtheoretischen Modells zur Änderung des Rauchverhaltens
Authors: Tönjes Britt , Meyer Christian , Ulbricht Sabina , Schumann Anja , Rüge Jeanette , Rumpf Hans-Jürgen , John Ulrich
Published: May 2007

Zusammenfassung. Das Transtheoretische Modell der Verhaltensänderung (TTM) stellt eine verbreitete theoretische Basis für die Konzeption von bevölkerungsbezogenen und individualisierten Interventionen dar. Voraussetzung hierfür ist eine valide, reliable und ökonomische Erfassung der Konstrukte des TTM. Für die Implementation derartiger Interventionen stellt die hausärztliche Praxis einen viel versprechenden Zugangsweg dar. Aussagekräftige Daten zu psychometrischen Eigenschaften deutschsprachiger Kurzskalen aus genanntem Setting fehlen jedoch bisher. Im Rahmen der vorliegenden Studie wurden 1653 rauchende Patienten (Teilnahmerate 82%) aus 34 zufällig ausgewählten hausärztlichen Praxen (Teilnahmerate 87%) schriftlich befragt. Es erfolgte eine Prüfung der psychometrischen Eigenschaften der Skalen Entscheidungsbalance, Selbstwirksamkeitserwartung und Prozesse der Verhaltensänderung. Es konnte für alle Skalen die postulierte faktorielle Struktur bestätigt werden. Die Skalen zur Entscheidungsbalance und zur Selbstwirksamkeitserwartung wiesen bei der Reliabilität Mängel auf. Die vorliegenden Kurzskalen und Normdaten bilden eine empirische Basis für die Individualisierung von Interventionen zur Abstinenzförderung in der hausärztlichen Praxis. Einschränkungen und Weiterentwicklungsbedarf der Skalen werden diskutiert.
Stressbelastung von Wiener Altenpflegerinnen aus Österreich, Osteuropa und Asien
Authors: Jenull-Schiefer Brigitte , Brunner Eva , Ofner Monika , Mayring Philipp
Published: May 2007

Zusammenfassung. In einer Fragebogenstudie an examinierten Pflegekräften (N = 195) aus Österreich, Osteuropa und Asien werden Arbeitsbelastungen, Gesundheitsverhalten und der Umgang mit Belastungen im Kontext stationärer Altenpflege aufgezeigt. Ergebnisse belegen unterschiedliche Belastungsschwerpunkte in den drei untersuchten Gruppen, wobei sich osteuropäische Pflegekräfte als besonders belastet zeigten. Ein hohes Bildungsniveau erwies sich im Umgang mit den Arbeitsbedingungen als hilfreich.
Dust emission response to climate in southern Africa
Authors: Bryant Robert G. , Bigg Grant R. , Mahowald Natalie M. , Eckardt Frank D. , Ross Simon G.
Published: May 2007

The processes which act in mineral dust source regions and factors which contribute to interannual variability within dust plumes emanating from them are poorly understood. In this case study, we focus on processes modulating emissions of atmospheric mineral aerosols from a large ephemeral lake. We focus on one key ephemeral lake dust source in southern Africa, the Makgadikgadi Pans of Botswana. A range of satellite [for example, Total Ozone Mapping Spectrometer (TOMS), Moderate Resolution Imaging Spectrometer (MODIS)] and climate data (from meteorological stations and reanalysis data sources) are extracted and compared, highlighting initial problems (for example, data quality, calibration, record length) associated with long‐term (10–20 years) monitoring of dust with regional sources in this and other dryland regions. Nevertheless, comparisons of satellite‐retrieved inundation, mineral aerosols, vegetation abundance, and climate data for the 1980–2000 period suggest that desert dust loadings are intermittently influenced by the extent and frequency of lake inundation, sediment inflows, and surface wind speed variability. In addition, a significant proportion of the observed variability in the dust and hydrological cycle of this source could also be attributed to El Niño‐Southern Oscillation (ENSO) and Indian Ocean sea surface temperature anomalies. Both are known to have an important role in modulating rainfall variability in southern Africa.
Integration of geochemical mass balance with sediment transport to calculate rates of soil chemical weathering and transport on hillslopes
Authors: Yoo Kyungsoo , Amundson Ronald , Heimsath Arjun M. , Dietrich William E. , Brimhall George H.
Published: May 2007

We developed a process‐oriented hillslope soil mass balance model that integrates chemical and physical processes within hillslope soils. The model explicitly factors that soil chemical weathering at any hillslope position is related to the flux of soil eroded from upslope as well as soil production from underlying bedrock. The model was merged with measurements of soil elemental chemistry and cosmogenic radionuclide‐based saprolite‐to‐soil conversion rates along a 50 m transect of a semiarid granodiorite hillslope in the southeastern Australian highlands. Inverse modeling results in the simultaneous quantification of the rates of soil chemical weathering and soil transport as a function of hillslope position. Soil chemical weathering rates per land surface area systematically varied along the transect from losses of 0.035 kg m−2 yr−1 on the ridge to gains of 0.035 kg m−2 yr−1 at the lowest slope position. The mass loss via soil chemical weathering would have been overestimated by 40% if the impact of soil transport on soil chemistry was ignored. The chemical mobility of elements, combined with biological nutrient demand, controlled the spatial redistribution of individual elements: P and Ca were preferentially retained relative to Si, Al, and Fe within the hillslope base. The calculated soil transport rate is linearly related to the product of soil thickness and slope gradient, instead of slope alone. Soil residence time was determined by calculating the time length for a 3 dimensional box (volume = 1 m2 surface area × soil thickness) to be entirely removed by mass flux of soil transport: 4 ka on the ridge to 0.9 ka at the hillslope base. These soil residence times, combined with soil chemical weathering rates, indicate that a 1 m2 area of soil loses ∼1,800 kg via chemical weathering while passing through the upslope portion of the hillslope, but that it regains ∼90 kg, probably via clay precipitation and biological retention of cations, during its passage through the lower segments of the transect. This study provides a previously unrecognized linkage between physical soil transport and soil chemical weathering that have implications for hillslope evolution as well as biogeochemistry.
Effect of global ocean temperature change on deep ocean ventilation
Authors: de Boer A. M. , Sigman D. M. , Toggweiler J. R. , Russell J. L.
Published: May 2007

A growing number of paleoceanographic observations suggest that the ocean's deep ventilation is stronger in warm climates than in cold climates. Here we use a general ocean circulation model to test the hypothesis that this relation is due to the reduced sensitivity of seawater density to temperature at low mean temperature; that is, at lower temperatures the surface cooling is not as effective at densifying fresh polar waters and initiating convection. In order to isolate this factor from other climate‐related feedbacks we change the model ocean temperature only where it is used to calculate the density (to which we refer below as “dynamic” temperature change). We find that a dynamically cold ocean is globally less ventilated than a dynamically warm ocean. With dynamic cooling, convection decreases markedly in regions that have strong haloclines (i.e., the Southern Ocean and the North Pacific), while overturning increases in the North Atlantic, where the positive salinity buoyancy is smallest among the polar regions. We propose that this opposite behavior of the North Atlantic to the Southern Ocean and North Pacific is the result of an energy‐constrained overturning.
Diurnally varying structure of stationary waves encircling the summer southern pole of Mars observed by MGS TES
Authors: Fukuhara Tetsuya , Imamura Takeshi
Published: May 2007

The diurnal variation in the vertical structure of the wavenumber‐1 stationary planetary wave observed in the summer southern polar region of Mars was investigated by using temperature data on the dayside and nightside taken by Thermal Emission Spectrometer onboard Mars Global Surveyor. It was found that the westward phase tilt with height during this period tends to be obvious on the dayside, while it is much less on the nightside. A possible explanation for the diurnally‐varying wave structure is the advection of wave fields by the tidal wind: the wave fields away from the ground surface are carried westward by the tidal wind during the local time from midnight to noon, and the process is reversed from noon to midnight. The slow vertical propagation of the wave with a time constant much longer than a sol will allow the tidal wind to influence the wave structure.
Full waveform earthquake location: Application to seismic streaks on the Calaveras Fault, California
Authors: Rubinstein Justin L. , Beroza Gregory C.
Published: May 2007

We use a novel technique based upon source array analysis to locate three moderate earthquakes that occur at the edge of previously identified streaks of seismicity on the Calaveras Fault, California. Our method determines centroid locations for earthquakes, in addition to the hypocenters previously determined using first‐break picks. Application of the method to smaller earthquakes indicates that the errors associated with the locations are on the order of 100 m, much less than the rupture dimensions of the M > 4.5 events that we have analyzed. We treat high‐precision locations of microearthquakes near the earthquakes that we want to locate as source arrays and compute the slowness of waves leaving these source arrays. We then use the slowness parameters to locate the earthquakes of interest. We find that the medium‐magnitude events nucleate on the streaks and rupture into a zone devoid of seismicity. On this basis, we argue that streaks represent the boundary between creeping and locked sections of a fault. Our location technique has the potential for wide application, including circumstances where it may be necessary or desirable to locate earthquakes without using direct arrivals.
Vibrational and thermodynamic properties of forsterite at mantle conditions
Authors: Li Li , Wentzcovitch Renata M. , Weidner Donald J. , Da Silva Cesar R. S.
Published: May 2007

We present a first‐principle study of the vibrational and thermodynamic properties of Mg2SiO4 forsterite up to 20 GPa. The calculated local density approximation (LDA) frequencies and their pressure dependence are in good agreement with the available Raman and infrared spectroscopy data. We also predict the pressure dependence of the modes which are yet to be measured. Thermodynamic properties are obtained using the quasi‐harmonic approximation (QHA) to the free energy in conjunction with these results. The calculated pressure‐volume‐temperature (P‐V‐T) relations and thermodynamic properties agree well with the reported experimental data within the regime of validity of the QHA. The only discrepancies with experimental data that point to intrinsic anharmonic effects are the mode Gruneisen parameters of two Raman and one infrared modes. However, their effect on thermodynamic properties appears to be negligible.
Observing the yield curve of compacted pack ice
Authors: Wang Keguang
Published: May 2007

A method for observing the yield curve of compacted pack ice is developed based on the characteristic analysis of the stress field within the pack ice. The analysis shows that the slope of the yield curve is associated with the angle between intersecting linear kinematic features; thus by measuring the intersection angles we can inversely estimate the yield curve. Applying this method to the observed angles generates a curved diamond yield curve, which possesses almost all the advantages identified by the other methods. However, due to the limited data available, more observations are favored to refine this yield curve.
A modeling study of the seasonal oxygen budget of the global ocean
Authors: Jin X. , Najjar R. G. , Louanchi F. , Doney Scott C.
Published: May 2007

An ecosystem model embedded in a global ocean general circulation model is used to quantify roles of biological and physical processes on seasonal oxygen variations. We find that the thermally induced seasonal net outgassing (SNO) of oxygen is overestimated by about 30% if gas phase equilibrium is assumed, and we find that seasonal variations in thermocline oxygen due to biology are approximated well using the oxygen anomaly. Outside the tropics and the north Indian Ocean, biological SNO is, on average, 56% of net community production (defined as net oxygen production above 76 m) during the outgassing period and 35% of annual net community production. In the same region the seasonal drawdown of the oxygen anomaly within the upper thermocline (76–500 m) is 76% of the remineralization during the drawdown and 48% of annual remineralization. Applying model‐derived relationships to observed O2climatologies and using independent estimates for tropical and monsoonal systems, we estimate global net community production to be 14.9 ± 2.5 Pg C yr−1.
Effects of thermal tides on the Venus atmospheric superrotation
Authors: Takagi M. , Matsuda Y.
Published: May 2007

A nonlinear dynamical model on the sphere has been numerically integrated to investigate a generation mechanism of the Venus atmospheric superrotation by the thermal tides. By using the solar heating exciting the diurnal and semidiurnal tides, the atmospheric superrotation extending from the ground to 80 km is generated. The vertical distributions of the mean zonal flow obtained in our experiments are similar to the observations. Velocity of the mean zonal wind on the equator reaches about 60–100 m s−1 near the cloud top level. A linear theory suggests that the atmospheric superrotation obtained in the present study is generated and maintained by the momentum transport associated with the thermal tides. Namely, the downward transport of zonal momentum that is associated with the downward propagating semidiurnal tide excited in the cloud layer induces the mean zonal flow opposite to the Venus rotation in the lowest layer adjacent to the ground. Surface friction acting on this counter flow provides the atmosphere with the net angular momentum from the solid part of Venus. It is examined how the atmospheric superrotation depends on vertical eddy viscosity and Newtonian cooling. The result shows that magnitude of the atmospheric superrotation is not so sensitive to vertical eddy viscosity but is strongly influenced by Newtonian cooling.