bluuebunny/crossref_metadata_2025 huggingface dataset:
Chemistry and Enterohepatic Circulation of Bile Acids† ‡ § ¶ # ‖ ** †† ‡‡ §§ ¶¶ ‖‖ ##
Authors: Hofmann Alan F.
Published: September 2008

A brief review is given of the chemistry of bile acids, emphasizing the relationship between chemical structure, physical properties and enterohepatic cycling of the major primary and secondary bile acids. Features of the enterohepatic circulation of primary and secondary bile acids in man are summarized. The effects of bile acid feeding on the composition of the enterohepatic circulation in man are reviewed. Methods for characterizing the enterohepatic circulation of bile acids in man are tabulated.
Biliary Lipid Secretion in Health and in Cholesterol Gallstone Disease
Authors: Carey Martin C. , Mazer Norman A.
Published: September 2008

The secretory compartment for biliary lecithin and cholesterol secretion probably resides in the smooth endoplasmic reticulum of the hepatocyte. The secretory compartment for bile salts lies predominantly in the enterohepatic circulation which fluxes bile salts continuously through the smooth endoplasmic reticulum compartment and extracts lipids for secretion into bile. Most of bile lecithin is newly synthesized by the liver; most of bile cholesterol is derived from extrahepatic sources. Both cholesterol and lecithin secretion are coupled to bile salt secretion and describe output curves which can be fitted by rectangular hyperbolae: since bile salt secretion is a linear function of input, the relative proportions of cholesterol to bile salts plus lecithin in bile increase at low bile salt outputs. In health, an adequate bile salt (+ lecithin) secretion coupled with normal cholesterol secretion maintains the relative composition of bile in a stable state: fasting compositions usually lie within the micellar zone or metastable supersaturated zone of a triangular coordinate-phase diagram plot. In cholesterol gallstone disease, mean bile salt (+ lecithin) secretion rates are subnormal and/or mean cholesterol secretion rates are supranormal, especially in the fasting state. If individuals are obese there is also enhanced hypersecretion of biliary cholesterol. Either or both secretory defects lead to an elevation and persistence of cholesterol supersaturation of bile. The physical state of the secreted lipids in bile is complex and fluctuant, and probably involves vesicle structures and mixed micelles at high water and cholesterol concentrations and predominantly micellar structures at low water and cholesterol concentrations. In lithogenic bile, the physical state, proportions and nucleation potential of the lipid aggregates are probably different. Further, the respective proportions of biliary mixed micelles and vesicles are probably influenced by the mean hydrophilicity of the bile salt pool.
Effects of Gallbladder Function on Human Bile: Compositional and Structural Changes
Authors: Holzbach Thomas R.
Published: September 2008

Water and electrolyte absorption leading to increased intraluminal concentrations of lipids and other solutes comprise the primary physiologic effect of the gallbladder. The dynamics of entero-hepatic circulation can lead to confinement of up to 60% of the bile acid pool within the gallbladder during prolonged fasting. This bile acid sequestration markedly reduces both the bile salt secretory rate and total solute concentration in comparison with the nonfasting state producing hepatic bile that is more than normally dilute especially in comparison with gallbladder bile. These conditions favor formation of small low-density vesicles in hepatic bile which are more buoyant than the concentrated biliary micelles found in anatomically dependent regions of the gallbladder. Vesicle formation in hepatic bile may explain the “stratification” phenomenon often noted within the gallbladder. This observation could be accounted for by inhomogeneous mixing of the dissimilar lipid particles, i.e., vesicles and micelles. If vesicles are present and stratified as presumed, the overall cholesterol transporting capability of the total lipid particles, including these regionalized vesicles, would be considerably enhanced. The net effect of this process would lead to an overestimation of the true degree of metastable cholesterol supersaturation for the biliary micellar system within the gallbladder on the incorrect assumption of homogeneous mixing of lipids.
The Ionization Behavior of Fatty Acids and Bile Acids in Micelles and Membranes
Authors: Small Donald M. , Cabral Donna J. , Cistola David P. , Parks John S. , Hamilton James A.
Published: September 2008

The ionization behavior of carboxylic acids including aliphatic chain fatty acids and bile acids in solutions, micelles, membranes and proteins is of considerable biological interest. The 13C nuclear magnetic resonance chemical shift of carboxyl carbon of a variety of acids has been shown to be a linear function of the state of ionization of the carboxyl group. Thus, by measuring the chemical shift as a function of the amount of acid or base added to a solution, the state of ionization and the apparent pKa of the carboxyl group may be determined. The method is illustrated in this paper using butyric acid, and results (given as apparent pKa values) are tabulated for a variety of fatty acids and cholic acid in different environments such as monomeric solutions, micelles, membranes and bound to albumin. The apparent pKa varies greatly depending upon the environment. For instance, the apparent pKa of oleic acid is about 4.2 when bound to albumin whereas it is about 7.5 when incorporated in the bilayer of a phospholipid vesicle. Cholic acid shows similar changes in the apparent pKa, being approximately 5.2 in sodium taurocholate micelles and at least 6.8 in phospholipid vesicles. The use of 13C nuclear magnetic resonance (NMR) and, in particular, I3C NMR of 13C-enriched carboxyl groups provides a method for direct observation of the state of ionization of the carboxyl group in biologically interesting acids. Such techniques may be adapted for use in biological systems, such as cells or tissues.
Kinetics and Thermodynamics of Dissolution of Lecithin by Bile Salts
Authors: Lindenbaum Siegfried , Rajagopalan Natarajan
Published: September 2008

The kinetics of dissolution of dispersions of egg phosphatidylcholine (lecithin) by bile salts was studied by observing the decrease in turbidity as mixed micelles of lecithin and bile salts were formed. The rate of dissolution of lecithin corresponding to formation of mixed micelles was studied in the presence of dihydroxy bile salts, sodium deoxycholate, sodium chenodeoxycholate, sodium ursodeoxycholate and one trihydroxy bile salt, sodium cholate. The rate of dissolution of lecithin and mixed micelle formation decreased in the order: chenodeoxycholate ± deoxycholate ± cholate ± ursodeoxycholate. Kinetic solvent isotope studies in D2O, along with measurement of enthalpies of mixed micelle formation both in H2O and D2O, suggest that formation and stabilization of mixed micelles are related to “hydrophobicity” as estimated by high performance liquid chromatography retention factors.
Dissolution Rate of Cholesterol in Monooctanoin
Authors: Bogardus Joseph B.
Published: September 2008

Monooctanoin is used clinically for dissolution of common bile duct cholesterol gallstones. A number of factors influencing the dissolution rate of cholesterol monohydrate in this solvent were investigated. Water increased cholesterol dissolution rate in a manner inconsistent with previous solubility measurements. Dissolution rate increased approximately 50% in the presence of 10 to 15% water in monooctanoin. Further studies on viscosity, the effect of polymers and temperature showed that the solvent viscosity had a dominating influence on dissolution rate. This was thought to be caused by the interaction of cholesterol with the solvent in the dissolving surface layer which caused a decrease in the diffusion coefficient (and dissolution rate) of cholesterol. Reducing viscosity and increasing temperature were identified as possible approaches for increasing cholesterol gallstone dissolution rate in monooctanoin.
Animal Models of Cholesterol Gallstone Disease
Authors: Holzbach Thomas R.
Published: September 2008

There is no genetically susceptible, spontaneous and naturally occurring animal model for human cholesterol cholelithiasis. The disease has been reported to occur spontaneously only rarely in some primates. The human disease is probably multifactorial; therefore, the finding or development through inbreeding of a spontaneous genetic model is unlikely. The two most popular animals in use today as models are rodent species: hamster and prairie dog. Despite widely different means of dietary induction of the disease in the two, the feature common to both is cholesterol overload. In the case of the essential fatty acid-deficient hamster, the predominant defect is a unique endogenous overproduction through increased total body synthesis of cholesterol. In the prairie dog, the cholesterol overload is simply exogenous due to massive and rapid intestinal absorption. Neither model is remotely physiological. Although a number of useful aspects of the lithogenic process can be studied using these models, certain changes apparently associated with the formation of gallstones under these conditions may in part be a function of the unphysiological dietary requirements for induction of the disease.
Test positivity cutoff level of a high risk human papillomavirus test could be increased in routine cervical cancer screening
Authors: Kotaniemi‐Talonen Laura , Malila Nea , Nieminen Pekka , Anttila Ahti , Tarkkanen Jussi , Laurila Pekka , Hakama Matti
Published: September 2008

We present data on test positivity, relative sensitivity, rates of detection and relative specificity for primary human papillomavirus (HPV) testing with different cutoff levels for test positivity, in comparison to conventional cytology. In 2003–2004, 18,438 women were screened primarily with Hybrid Capture 2 (HC 2) assay, a test for oncogenic HPV DNA, and 21,446 with conventional cytology within the organised screening programme in Finland. A cytological triage test was performed for the HPV positives. Women with cytology equal to low grade squamous intraepithelial lesion (LSIL) or worse were referred for colposcopy. The relative sensitivity measured as relative risk (RR) of any cervical intraepithelial neoplasia (CIN) or cancer was 1.58 for the HPV test at the relative light units (rlu) ratio cutoff 1.00, in comparison to cytology. With the cutoff 3.00, all CIN 2+ lesions were detected. With cutoff 10.00, 2 of the 22 CIN 3+ lesions were missed. Relative specificity for HPV screening for any CIN was 92.6% at cutoff 1.00, 94.6% at cutoff 3.00 and 96.3% at cutoff 10.00. For CIN 3+ specificity estimates for these cutoffs were 92.1%, 94.1% and 95.8%, respectively. Used for routine screening as the sole test, the HPV test cutoff can be increased from the level recommended for clinical use. With HC 2, the detection rate at rlu ratio cutoff 10.00 is still at the level of high‐quality conventional screening. At that level, the false positive rate is reduced by about half and the specificity of the HPV test becomes equal to the average specificity of conventional cytology. © 2008 Wiley‐Liss, Inc.
The effect of smoking on the male excess of bladder cancer: A meta‐analysis and geographical analyses
Authors: Hemelt Marjolein , Yamamoto Hidekazu , Cheng Kar K. , Zeegers Maurice P.A.
Published: September 2008

Smoking is considered the primary risk factor for bladder cancer. Although smoking prevalence and bladder cancer incidence vary around the world, bladder cancer is on average 4 times more common in males than in females. This article describes the observed male–female incidence ratio of bladder cancer for 21 world regions in 2002 and 11 geographical areas during the time period 1970–1997. A meta‐analysis, including 34 studies, was performed to ascertain the increased risk for bladder cancer in males and females when smoking. The summary odds ratios (SORs) calculated in the meta‐analysis were used to estimate the male–female incidence ratio of bladder cancer that would be expected for hypothetical smoking prevalence scenarios. These expected male–female incidence ratios were compared with the observed ratios to evaluate the role of smoking on the male excess of bladder cancer. The male–female incidence ratio of bladder cancer was higher than expected worldwide and over time, based on a smoking prevalence of 75% in males, 10% in females and an increased risk (SOR) of bladder cancer associated with smoking of 4.23 for males and 1.35 for females, respectively. This implied that, at least in the Western world, smoking can only partially explain the difference in bladder cancer incidence. Consequently, other factors are responsible for the difference in bladder cancer incidence. © 2008 Wiley‐Liss, Inc.
Survival of peritoneal malignant mesothelioma in Italy: A population‐based study
Authors: Mirabelli Dario , Roberti Sara , Gangemi Manuela , Rosato Rosalba , Ricceri Fulvio , Merler Enzo , Gennaro Valerio , Mangone Lucia , Gorini Giuseppe , Pascucci Cristiana , Cavone Domenica , Nicita Carmela , Barbieri Pietro Gino , Marinaccio Alessandro , Magnani Corrado , Montanaro Fabio
Published: September 2008

In some population‐based studies, a shorter median survival was observed in peritoneal as compared with pleural, malignant mesothelioma, but in others, longer median survival times or higher proportions of long‐term survivors were reported. Statistical instability could have caused these differences. We analyzed survival in peritoneal mesothelioma in a large and unselected population‐based case series. Cases (338) registered from 1990 to 2001 by 9 Italian regional mesothelioma registries contributing to the network of the National Mesothelioma Registry were followed until December 31, 2005. Univariate (Kaplan‐Meier) and multivariate (Cox proportional hazards regression) analyses of survival were performed according to selected individual characteristics, including limited treatment information in a subset of 194 cases. The results were compared with those obtained in a parallel study on pleural mesothelioma cases. Epithelioid histotype, younger age at diagnosis and, to a lesser degree, gender (women), and being diagnosed in a hospital with a thoracic surgery unit positively and significantly affected survival. The effect of treatment was positive but not statistically significant. No trend in the risk of death according to calendar period of diagnosis was present. Peritoneal mesothelioma cases had shorter median survival time than pleural cases, but a larger proportion of long‐term survivors. Survival patterns after peritoneal and pleural mesothelioma differed markedly. Treatment was not associated with a statistically significant improvement in survival, but our study included cases first diagnosed before the introduction of the most recent therapeutic approaches. This provides a large historical comparison for future studies on survival trends at the population level. © 2008 Wiley‐Liss, Inc.
Use of proliferation tests to evaluate the effects of complexing agents on beryllium toxicity
Authors: Stephan Chadi H. , Sauvé Sébastien , Fournier Michel , Brousseau Pauline
Published: September 2008

Occupational exposure to beryllium may cause chronic beryllium disease (CBD), a granulomatous interstitial pneumonitis caused by a cell‐mediated immune response with delayed hypersensitivity initiated by an electrostatic interaction with the MHC class II human leukocyte antigen (HLA). Increased research efforts focus on the development of a CBD treatment by chelation therapy. This work presents anin vitroevaluation of the beneficial effects of beryllium chelation with different organic substrates. We have used a standard beryllium lymphocyte proliferation test (BeLPT) adapted for mouse splenocytes. Three complexing agents, 4,5‐dihydroxy‐1,3‐benzenedisulfonic acid (tiron), nitrilotripropionic acid (NTP) and nitrilotriacetic acid (NTA), were tested using different protocols of the splenocyte proliferation test (SPT). We studied their corrective effect (beryllium pre‐exposed splenocytes), their protective effect (ligand pre‐exposed splenocytes) and their combined effects at fixed Be:L ratio of 1:2, at fixed Be concentration and at fixed L concentration. We also studied the effect of tiron in preventing splenocyte sensitization to beryllium. All three complexing agents showed a corrective effect and proved efficient in the combined effects, except NTA in the fixed Be:L ratio. Only NTP and tiron showed a significant protection at lower beryllium concentrations, while NTA was not significant. Splenocytes pre‐exposed to chelated beryllium did not show sensitization while splenocytes pre‐exposed to beryllium were sensitized. We observed a strong correlation between the efficiency of the complexing agent and its affinity towards beryllium. Both tiron and NTP showed a similar affinity towards the beryllium ion that is 107higher than that of NTA. Copyright © 2008 John Wiley & Sons, Ltd.
Growth of three bacteria in arsenic solution and their application for arsenic removal from wastewater
Authors: Mondal P. , Majumder C. B. , Mohanty B.
Published: September 2008

The present paper compares the arsenic removal capacities of three bacterial strains namely, Ralstonia eutropha MTCC 2487, Pseudomonas putida MTCC 1194 and Bacillus indicus MTCC 4374 form wastewater (simulated acid mine drainage) containing arsenic (As(III):As(V)::1:1), Fe, Mn, Cu and Zn in the concentration of 15 mg/l, 10 mg/l, 2 mg/l, 5 mg/l and 10 mg/l respectively, in bulk liquid phase. Growth patterns of these bacteria in presence of arsenic in solution as well as under starvation have also been investigated as the acid mine drainage normally does not contain organic carbon and also contains high arsenic. At the nutrient broth concentration of 1.25 g/l and in presence of 15 mg/l arsenic sufficient growth of these strains have been observed. However, growth of Ralstonia eutropha MTCC 2487 has been found slightly more than Pseudomonas putida MTCC 1194 and Bacillus indicus MTCC 4374. Arsenic removal capacities of Ralstonia eutropha MTCC 2487, Pseudomonas putida MTCC 1194 and Bacillus indicus MTCC 4374 from simulated acid mine drainage are ∼67%, 60% and 61% respectively. It has also been observed that arsenic concentration of 15 mg/l prolongs the stationary phase of these strains. pH and temperature for the above studies have been maintained at 7.1 ± 0.1 and 29 ± 1 °C, respectively. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Isolation and characterization of potential probiotic lactobacilli from pig feces
Authors: Yun Ji Hyun , Lee Ki Beom , Sung Youn Kyoung , Kim Eun Bae , Lee Hong‐Gu , Choi Yun Jaie
Published: September 2008

This study examined four lactobacilli isolated from pig feces. Two hundred lactic acid bacteria strains were obtained from pig feces using selective culture media (with vancomycin and bromocresol green; termed LAMVAB agar). Microscopy, the catalase test, Gram‐staining, and RAPD‐PCR analysis were used to group the bacteria into 20 related clusters. Phenotypic analysis using the API 50 CH test and genotypic analysis of 16S rDNA sequences identified these clusters as representing single strains of each of Lactobacillus fermentum, Lactobacillus salivarius, Lactobacillus plantarum, and Lactobacillus reuteri. Bacterial survival under the conditions of low pH (2.0) and high concentration (5.0%, w/v) of bile salt was much better than that of the reference strain (Lactobacillus acidophilus ATCC 33199). The isolated bacteria were quite capable of inhibiting the growth of two pathogens, Escherichia coli K88 and Salmonella typhimurium. The high acid‐resistance, bile resistance and antagonism against pathogens, suggest that the four lactic acid bacteria isolated from pig feces could prove useful as piglet probiotics. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The texture of cooked potatoes: A review
Authors: Warren Donald S. , Woodman John S.
Published: September 2008

The literature concerning cooked‐potato texture is reviewed and discussed in the light of three new hypotheses. First, that “mealiness” is the subjective perception of the flow characteristics (“viscosity”) of cooked tissue and that this aspect of texture is controlled primarily by the solids content of the tuber. Second, that the reduction in tissue strength which occurs on cooking is due to water uptake by the polysaccharides of the cell wall. This increases the thickness of the cell wall and reduces the viscosity of the cell wall matrix: both effects combine to reduce the stress required to separate cells. Third, that, when the intrinsic properties of the cell wall material lead to excessive hydration, the adhesion between cells may be sufficiently reduced to allow spontaneous separation or “sloughing”.
Chemotaxonomy of bacteria by comprehensive GC and GC‐MS in electron impact and chemical ionisation mode
Authors: David Frank , Tienpont Bart , Sandra Pat
Published: September 2008

The analysis of the cellular lipidic fraction of bacteria is described. After hydrolysis and methylation, the fatty acid methyl esters (FAMEs) are determined by 1‐D GC using the Sherlock MIDI bacteria identification system, by comprehensive GC (GC×GC) and by GC‐MS in electron impact (EI) and positive chemical ionisation (PCI) mode. With GC×GC, the enhanced selectivity and group type separation provides a more complete elucidation of the fatty acids in microorganisms. GC‐EI‐MS and GC‐PCI‐MS were helpful for confirmation. The bacteria selected in this study are Brevundimonas diminuta, Chryseobacterium gleum and Stenotrophomonas maltophilia.
Construction of a new interface for comprehensive supercritical fluid chromatography×reversed phase liquid chromatography (SFC×RPLC)
Authors: François Isabelle , dos Santos Pereira Alberto , Lynen Frédéric , Sandra Pat
Published: September 2008

The design of a new interface to hyphen high efficiency supercritical fluid chromatography (SFC) and fast RPLC in a comprehensive configuration is described. SFC×RPLC is a viable alternative to normal phase (NP) LC×RPLC and is characterized by high orthogonality. Compared to NPLC×RPLC an additional advantage is the expansion of supercritical carbon dioxide (CO2) when exposed to atmospheric pressure leading to fractions consisting of solvents that are miscible with the second dimension RPLC mobile phase. The interface consists of a two‐position/ten‐port switching valve equipped with two packed octadecyl silica (C18) loops for effective trapping and focusing of the analytes after elution from the SFC dimension. The addition of a water make‐up flow to the SFC effluent prior to entering the loops is of fundamental importance to efficiently focus the solutes on the C18 material and to reduce interferences of expanded CO2 gas on the second dimension separation. The features of the system are illustrated with the analysis of a lemon oil sample.
A global sensitivity study of sulfur chemistry in a premixed methane flame model using HDMR
Authors: Ziehn T. , Tomlin A. S.
Published: September 2008

The use of complex mechanisms is increasing within models describing a range of important chemical processes, including combustion. Parameters describing chemical reaction rates and thermodynamics can often be very uncertain. Highlighting the main parameters contributing to predictive uncertainty is an important part of model development. However, due to the computational cost of the models and their nonlinearity, traditional methods for sensitivity analysis are often not suitable. The high‐dimensional model representation (HDMR) method was developed to express the input–output relationship of a complex model with a high‐dimensional input space. A fully functional surrogate model can be constructed with low computational effort. First‐ and second‐order sensitivity indices can then be calculated in an automatic way, over large input parameter ranges. These provide an importance ranking for the input parameters. An extension to the existing set of HDMR tools is developed in this work, where the number of HMDR component functions can be reduced to explore large dimensional input spaces very efficiently. The HDMR tools are demonstrated for a case study of a one‐dimensional low‐pressure premixed methane flame model doped with trace sulfur and nitrogen species. Uncertainties in rate constants and thermodynamic data are considered, leading to a study of 176 input parameters. Using the new HDMR tools, the use of screening methods such as the Morris method, which aim to identify unimportant parameters beforehand, can generally be avoided. However, in certain cases, a combination of a screening method and HDMR is computationally more efficient than using HDMR alone. The final ranking of important parameters is shown to be critically dependent on the uncertainty ranges chosen due to the nonlinearity of the model. The study demonstrates that the proposed HDMR method provides a powerful tool for general application to global sensitivity analysis of complex chemical mechanisms. © 2008 Wiley Periodicals, Inc. Int J Chem Kinet 40: 742–753, 2008
Study of the Interaction of Aglycon of Daunorubicin with Human Serum Albumin by Spectroscopy and Modeling
Authors: Cui Fengling , Qin Lixia , Zhang Guisheng , Yao Xiaojun , Lei Beilei
Published: September 2008

The interaction between aglycon of daunorubicin (DNR‐A) and human serum albumin (HSA) was investigated using fluorescence quenching and modeling. Results shown that fluorescence quenching of HSA by DNR‐A resulted from the formation of DNR‐A‐HSA complex. The quenching constants were determined via measurement of the binding affinity between DNR‐A and HSA using the Stern‐Volmer equation. The thermodynamic parameters ΔG, ΔH,ΔSand the binding distancerwere calculated. Furthermore, SFS and UV spectra suggested that the complex changed the conformation of HSA and that hydrophobic interactions played a major role in DNR‐A‐HSA association, which was in good agreement with the results of the modeling study. Moreover, the SFS technique was successfully applied to determine the total proteins in biology samples with satisfactory results.

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One‐Pot Synthesis of Hyperbranched Polyethylenes Tethered with Pendant Acryloyl Functionalities by Chain Walking Copolymerizations
Authors: Morgan Shawn , Ye Zhibin , Zhang Kejian , Subramanian Ramesh
Published: September 2008

Chain walking copolymerization of ethylene with 1,4‐butanediol diacrylate at elevated concentrations for the synthesis of low‐viscosity hyperbranched polyethylenes tethered with a controllable amount of acryloyl functionality is reported. At concentrations much higher than the critical gelation concentrations, the diacrylate comonomer is copolymerized predominantly following the mono‐insertion pattern. A range of hyperbranched polyethylenes tethered with acryloyl functionality (1.3–4.8 mol‐%) and having low melt viscosity (ca. 25 Pa · s at 25 °C) and low glass transition temperature (Tg = −69 °C) has been synthesized. This unique method is specific to the Pd‐diimine‐catalyzed chain‐walking copolymerization system.

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Synthesis of Well‐Defined Figure‐of‐Eight‐Shaped Polymers by a Combination of ATRP and Click Chemistry
Authors: Shi Gang‐Yin , Pan Cai‐Yuan
Published: September 2008

Well‐defined figure‐of‐eight‐shaped (8‐shaped) polystyrene (PS) with controlled molecular weight and narrow polydispersities has been prepared by the combination of atom transfer radical polymerization (ATRP) and click chemistry. The synthesis involves two steps: 1) Preparation of a linear tetrafunctional PS with two azido groups, one at each end of the polymer chain, and two acetylene groups at the middle of the chain. 2) Intramolecular cyclization of the linear tetrafunctional PS at a very low concentration by a click reaction to produce the 8‐shaped polystyrenes. The resulting intermediates and the target polymers were characterized by 1H NMR and FT‐IR spectroscopy, and gel permeation chromatography. The glass transition temperatures (Tgs) were determined by differential scanning calorimetry and it was found that the decrease in chain mobility by cyclization resulted in higher Tgs for 8‐shaped polystyrenes as compared to their corresponding precursors.

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Anxiety rating scales in Parkinson's disease: Critique and recommendations
Authors: Leentjens Albert F.G. , Dujardin Kathy , Marsh Laura , Martinez‐Martin Pablo , Richard Irene H. , Starkstein Sergio E. , Weintraub Daniel , Sampaio Christina , Poewe Werner , Rascol Oliver , Stebbins Glenn T. , Goetz Christopher G.
Published: September 2008

Anxiety syndromes are common in patients with Parkinson's disease (PD) with up to 30% suffering from panic disorder, and up to 11% from generalized anxiety disorder (GAD). Anxiety is associated with increased subjective motor symptoms, more severe gait problems, dyskinesias, freezing, and on/off fluctuations. Anxiety has a negative impact on health related quality of life and is strongly associated with depressive syndromes. Since a variety of anxiety scales have been used in PD patients, the Movement Disorder Society commissioned a task force to assess the clinimetric properties of these scales in PD. A systematic review was conducted to identify anxiety scales that have either been validated or used in patients with PD. Six anxiety rating scales were identified. These were the Beck anxiety inventory, the hospital anxiety and depression scale, the Zung self‐rating anxiety scale and anxiety status inventory, the Spielberger state trait anxiety inventory, and the Hamilton anxiety rating scale. In addition, Item 5 (anxiety) of the neuropsychiatric inventory was included in the review. No scales met the criteria to be “recommended,” and all scales were classified as “suggested.” Essential clinimetric information is missing for all scales. Because several scales exist and have been used in PD, the task force recommends further studies of these instruments. If these studies show that the clinimetric properties of existing scales are inadequate, development of a new scale to assess anxiety in PD should be considered. © 2008 Movement Disorder Society
Development of the Bipolar Inventory of Symptoms Scale: concurrent validity, discriminant validity and retest reliability
Authors: Gonzalez Jodi M. , Bowden Charles L. , Katz Martin M. , Thompson Peter , Singh Vivek , Prihoda Thomas J. , Dahl Martha
Published: September 2008

Scales used in studies of bipolar disorder have generally been standardized with major depressive or hospitalized manic patients. A clinician rated scale based on a semi‐structured interview for persons with bipolar disorder, with comprehensive coverage of bipolar symptomatology, is needed. We report concurrent, divergent and convergent psychometric reliability, discriminant validity and relationship to a measure of overall function for a new psychometric rating instrument. A primarily outpatient sample of 224 subjects was assessed using the Bipolar Inventory of Symptoms Scale (BISS). The BISS total score and depression and mania subscales were compared to the Young Mania Rating Scale (YMRS), the Montgomery Asberg Depression Rating Scale (MADRS) and the Global Assessment of Functioning Scale (GAF). Clinical mood states were also compared using the BISS. The BISS scores demonstrated good concurrent validity, with estimates (Pearson correlations) ranging from 0.74 to 0.94 for YMRS and MADRS and test–retest reliability from 0.95 to 0.98. BISS concurrent validity with the GAF was significant for four clinical states, but not mixed states. The BISS discriminated primary bipolar mood states as well as subjects recovered for eight weeks compared to healthy controls. In conclusion, the BISS is a reliable and valid instrument broadly applicable in clinical research to assess the comprehensive domains of bipolar disorder. Future directions include factor analysis and sensitivity to change from treatment studies. Copyright © 2008 John Wiley & Sons, Ltd.
Living cationic polymerization of vinyl ethers in the presence of a strong base: Poisonous or helpful?
Authors: Yonezumi Motomasa , Takano Nanako , Kanaoka Shokyoku , Aoshima Sadahito
Published: September 2008

A quite small dose of a poisonous species was found to induce living cationic polymerization of isobutyl vinyl ether (IBVE) in toluene at 0 °C. In the presence of a small amount of N,N‐dimethylacetamide, living cationic polymerization of IBVE was achieved using SnCl4, producing a low polydispersity polymer (weight–average molecular weight/number–average molecular weight (Mw/Mn) ≤ 1.1), whereas the polymerization was terminated at its higher concentration. In addition, amine derivatives (common terminators) as stronger bases allow living polymerization when a catalytic quantity was used. On the other hand, EtAlCl2 produced polymers with comparatively broad MWDs (Mw/Mn ∼ 2), although the polymerization was slightly retarded. The systems with a strong base required much less quantity of bases than weak base systems such as ethers or esters for living polymerization. The strong base system exhibited Lewis acid preference: living polymerization proceeded only with SnCl4, TiCl4, or ZnCl2, whereas a range of Lewis acids are effective for achieving living polymerization in the conventional weak base system such as an ester and an ether. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 6746–6753, 2008
Preparation of star block copolymers with polystyrene‐block‐poly(ethylene oxide) as side chains on hyperbranched polyglycerol core by combination of ATRP with atom transfer nitroxide radical coupling reaction
Authors: Liu Chao , Pan Mugang , Zhang Yi , Huang Junlian
Published: September 2008

The star block copolymers with polystyrene‐block‐poly(ethylene oxide) (PS‐b‐PEO) as side chains and hyperbranched polyglycerol (HPG) as core were synthesized by combination of atom transfer radical polymerization (ATRP) with the “atom transfer nitroxide radical coupling” (“ATNRC”) reaction. The multiarm PS with bromide end groups originated from the HPG core (HPG‐g‐(PS‐Br)n) was synthesized by ATRP first, and the heterofunctional PEO with α‐2,2,6,6‐tetramethylpiperidinyl‐1‐oxy group and ω‐hydroxyl group (TEMPO‐PEO) was prepared by anionic polymerization separately using 4‐hydroxyl‐2,2,6,6‐tetramethylpiperidinyl‐1‐oxy (HTEMPO) as parents compound. Then ATNRC reaction was conducted between the TEMPO groups in PEO and bromide groups in HPG‐g‐(PS‐Br)n in the presence of CuBr and pentamethyldiethylenetriamine (PMDETA). The obtained star block copolymers and intermediates were characterized by gel permeation chromatography, nuclear magnetic resonance spectroscopy, fourier transform‐infrared in detail. Those results showed that the efficiency of ATNRC in the preparation of multiarm star polymers was satisfactory (>90%) even if the density of coupling cites on HPG was high. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 6754–6761, 2008
A comparative analysis of SET‐LRP of MA in solvents mediating different degrees of disproportionation of Cu(I)Br
Authors: Lligadas Gerard , Percec Virgil
Published: September 2008

Cu(I)Br/Me6‐TREN species are unstable and disproportionate into metallic Cu(0) and Cu(II)Br2/Me6‐TREN in DMSO, whereas in toluene are stable and do not undergo disproportionation, at least at 25 °C. To estimate the role of the disproportionating solvent in single electron‐transfer living radical polymerization (SET‐LRP) a comparative analysis of Cu(0)/Me6‐TREN‐catalyzed polymerization of MA initiated with methyl 2‐bromopropionate at 25 °C was performed in DMSO and toluene. A combination of kinetic experiments and chain end analysis by 500‐MHz1H NMR spectroscopy was used to demonstrate that disproportionation represents the crucial requirement for a successful SET‐LRP of MA at 25 °C. In DMSO a perfect SET‐LRP occurs and yields close to 100% conversion in 45 min. A first order polymerization in growing species up to 100% conversion and a PMA with perfectly functional chain ends are obtained. However, in toluene within 17 h only about 60% conversion is obtained, the polymerization does not show first order in growing species and therefore is not a living polymerization. Moreover, at 60% conversion the resulting PMA has only 80% active chain ends. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 6880–6895, 2008
Screening for distress can predict loss of follow‐up and treatment in cancer patients: results of development and validation of the Distress Inventory for Cancer Version 2
Authors: Thomas B. C. , Thomas I. , Nandamohan V. , Nair M. K. , Pandey M.
Published: September 2008

Introduction: The evidence suggests that in most instances distress from cancer goes unrecognised. There has been substantial work in screening for distress leading to development in practice guidelines recommending screening for distress. There is a need to identify distress early in the continuum, where suitable and timely interventions will benefit the patient. The Distress Inventory for Cancer (DIC) was designed for this.

Methods: The present study reports the improved psychometric properties of the second version of the DIC (DIC 2). A standardisation sample of 520 patients was administered the 73‐item draft questionnaire as well as the Functional Assessment of Cancer Therapy—General (FACT‐G). Additional 240 patients were administered Hospital Anxiety and Depression Scale (HADS) besides the final DIC 2 and FACT‐G. Internal consistency was measured with the Cronbach's alpha. Chi‐square, odds ratio, and binary logistic regression were used to compare the results of three tools and to establish validity.

Results: A principal factor analysis of the 73‐item draft questionnaire with varimax rotation in a six‐factor structure resulted in 33 items. Activity of daily living emerged as a single item domain. The FACT‐G scores negatively correlated with DIC 2 scores, while emotional distress of DIC 2 overlapped with anxiety in HADS. DIC 2 significantly predicted patient non‐compliance to treatment and follow‐up.

Conclusion: The results show a suitable internal consistency, construct, and convergent/divergent validity of the global distress measure (DIC 2). The DIC 2 also demonstrates a predictive function for future negative clinical behaviour, the knowledge of which may facilitate better intervention triage. Copyright © 2008 John Wiley & Sons, Ltd.
Optimal nonlinear objective analysis
Authors: Lorenc Andrew C.
Published: September 2008

Some practical problems in objective analysis for numerical weather prediction are best solved by using nonlinear analysis equations. They include the existence of nonlinear prior constraints on the analysis, and the use of observations which are nonlinearly related to the analysis parameters, or which have non‐Gaussian error distributions. Bayesian methods are used to derive equations for the optimal (maximum likelihood) nonlinear analysis. It is shown how to incorporate a strong constraint that the four‐dimensional evolution of the analysis should be consistent with a NWP model, by reduction of the control variable to the space‐dimensioned initial field for the model. The iterative solution of the nonlinear analysis equation then involves the integration of the NWP model, and its adjoint.

The behaviour of the nonlinear equations is demonstrated with a simple one‐dimensional shallow‐water model. It is shown that time‐tendency information, and indirect observations such as wind speed, or the movement of a tracer, can be used in the analysis. The resulting forecasts are better than those made from an analysis from a traditional analysis‐forecast cycle. The nonlinear method is shown to be capable of ‘moving’ a discontinuity similar to a front, to fit observations defining its position, thus giving an analysis with more detail than would be expected from the spatial resolution of the observations. The incorporation of additional nonlinear constraints, such as that used in initialization, is demonstrated. The method can be used to effectively reject observations with gross errors, by specifying a non‐Gaussian error distribution. However, this generates multiple minima which complicate the search for the best analysis, so the complex decision‐taking algorithms associated with other methods of quality control are not avoided.

The convergence properties of iterative methods of solution, and approximations to the ideal equations, are studied, in order to provide some indication as to whether the nonlinear effects might be allowed for in a practical analysis scheme.
A tight lower bound on the cover time for random walks on graphs
Authors: Feige Uriel
Published: September 2008

We prove that the expected time for a random walk to cover all n vertices of a graph is at least (1 + o(1))n In n.
Semiparametric Bayesian modeling of random genetic effects in family‐based association studies
Authors: Zhang Li , Mukherjee Bhramar , Hu Bo , Moreno Victor , Cooney Kathleen A.
Published: September 2008

We consider the inference problem of estimating covariate and genetic effects in a family‐based case‐control study where families are ascertained on the basis of the number of cases within the family. However, our interest lies not only in estimating the fixed covariate effects but also in estimating the random effects parameters that account for varying correlations among family members. These random effects parameters, though weakly identifiable in a strict theoretical sense, are often hard to estimate due to the small number of observations per family. A hierarchical Bayesian paradigm is a very natural route in this context with multiple advantages compared with a classical mixed effects estimation strategy based on the integrated likelihood. We propose a fully flexible Bayesian approach allowing nonparametric modeling of the random effects distribution using a Dirichlet process prior and provide estimation of both fixed effect and random effects parameters using a Markov chain Monte Carlo numerical integration scheme. The nonparametric Bayesian approach not only provides inference that is less sensitive to parametric specification of the random effects distribution but also allows possible uncertainty around a specific genetic correlation structure. The Bayesian approach has certain computational advantages over its mixed‐model counterparts. Data from the Prostate Cancer Genetics Project, a family‐based study at the University of Michigan Comprehensive Cancer Center including families having one or more members with prostate cancer, are used to illustrate the proposed methods. A small‐scale simulation study is carried out to compare the proposed nonparametric Bayes methodology with a parametric Bayesian alternative. Copyright © 2008 John Wiley & Sons, Ltd.
When work strain transcends psychological boundaries: an inquiry into the relationship between time pressure, irritation, work–family conflict and psychosomatic complaints
Authors: Höge Thomas
Published: September 2008

Against the theoretical background of the effort–recovery model and the action regulation theory, the author presents a cross‐sectional questionnaire study testing hypotheses about the relationship between work‐related time pressure, cognitive and emotional irritation, work–family conflict and psychosomatic complaints. Subjects were 576 female home care nurses. Results of a path analysis show that the relation of time pressure and psychosomatic complaints is partially mediated by experiencing a work–family conflict; also the relation of time pressure and work–family conflict is partially mediated by cognitive and emotional irritation. It is argued that cognitive and emotional irritation are fruitful concepts for a more comprehensive understanding of the relationship between work stressors and the development of strain‐based work–family conflict. Implications for the prevention of work–family conflict are outlined. Copyright © 2008 John Wiley & Sons, Ltd.
Relationships between self‐efficacy, social support and stress coping strategies in Chinese primary and secondary school teachers
Authors: Shen Yan E.
Published: September 2008

This study explored whether stress coping strategies could be predicted by general self‐efficacy and social support. Primary and secondary teachers (n = 530) completed measures of coping strategies, general self‐efficacy and social support. The results showed that teachers' general self‐efficacy and social support had direct and indirect predictive effects on different coping strategies, and they have more significant predictive effects on certain types of coping strategies. Teachers with higher general self‐efficacy and social support tended to adopt adaptive coping strategies or emotion‐oriented coping strategies. The study suggested that social support and self‐efficacy should be important factors to be considered when designing a prevention or intervention programme in the guidance of teachers' coping strategies and psychological counselling. Copyright © 2008 John Wiley & Sons, Ltd.
Role of clinical and ultrasound findings in the diagnosis of retained products of conception
Authors: Abbasi S. , Jamal A. , Eslamian L. , Marsousi V.
Published: September 2008

Objective

To assess the role of clinical and ultrasound findings as predictors of retained products of conception (RPOC) in women with a suspicion of incomplete miscarriage.

Methods

This was a retrospective study of 91 patients admitted for suspected RPOC after spontaneous first‐trimester miscarriage who were evacuated surgically, and for whom histopathological reports were available. All the women underwent transvaginal sonography after their miscarriage. The decision to evacuate the uterus was based on vaginal bleeding, lower abdominal pain and/or sonographic findings of hyperechoic material or endometrial thickness more than 8 mm. Maternal age, gestational age, clinical signs and symptoms and sonographic findings were recorded. Clinical and sonographic findings were compared with the histopathological reports and the sensitivity and specificity of vaginal bleeding, abdominal pain and sonographic appearance of the endometrium for detecting the products of conception were assessed.

Results

Histopathological analysis confirmed the presence of chorionic villi in 55 women (60%) and decidua in 36 (40%). Vaginal bleeding was more frequent in women with RPOC (P < 0.001), whilst lower abdominal pain was a more frequent symptom in those with decidua (P = 0.019). The ultrasound finding of hyperechoic material had a sensitivity of 78%, specificity of 100% and positive and negative predictive values of 100% and 75%, respectively, in predicting RPOC. Vaginal bleeding as a predictor of RPOC had a sensitivity of 93%, specificity of 50%, and positive and negative predictive values of 74% and 82%, respectively. The combination of hyperechoic material and/or vaginal bleeding increased the sensitivity to 98% and negative predictive value to 95%. There was no significant difference in endometrial thickness between the two groups.

Conclusion

The ultrasound finding of hyperechoic material is the best predictor for diagnosing RPOC. In the absence of hyperechoic material and vaginal bleeding, RPOC are extremely unlikely. Copyright © 2008 ISUOG. Published by John Wiley & Sons, Ltd.
Digital computer program for calculating selectivities of hydrogenation catalysts
Authors: Butterfield R. O. , Dutton H. J.
Published: September 2008

Linolenate and linoleate selectivities of hydrogenation catalysts are determined by a digital computer program which solves the kinetic equations of consecutive first‐order reactions. The described program is applicable to any initial oil or degree of hydrogenation.