bluuebunny/crossref_metadata_2025_split huggingface dataset:
Free‐radical copolymerization of ethyl α‐hydroxymethylacrylate with methyl methacrylate by reversible addition–fragmentation chain transfer
Authors: Cuervo‐Rodríguez R. , Bordegé V. , Sánchez‐Chaves M. , Fernández‐García M. 
Published: August 2006

AbstractThe controlled free‐radical homopolymerization of ethyl α‐hydroxymethylacrylate and copolymerization with methyl methacrylate were performed in chlorobenzene at 70 °C by the reversible addition–fragmentation chain transfer polymerization technique with 2,2′‐azobisisobutyronitrile as the initiator. 2‐Phenylprop‐2‐yl dithiobenzoate and 2‐cyanoprop‐2‐yl dithiobenzoate were used as chain‐transfer agents in the homopolymerization, whereas only the former was used in the copolymerization. All reactions presented pseudolinear kinetics. The effect of the monomer feed ratio on the copolymerization kinetics was examined. The conversion level decreased when the proportion of ethyl α‐hydroxymethylacrylate in the monomer feed was larger. Kinetic studies indicated that the radical polymerizations proceeded with apparent living character according to experiments, demonstrating an increase in the molar mass with the monomer conversion and a relatively narrow molar mass distribution. All copolymers were statistical in chain structure, as confirmed by determinations of the monomer reactivity ratios. The monomer reactivity ratios were determined, and the Mayo–Lewis terminal model provided excellent predictions for the variations of the intermolecular structure over the entire conversion range. Additionally, the chemical modification of poly(ethyl α‐hydroxymethylacrylate) was carried out to introduce glucose pendant groups into the structure. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 5618–5629, 2006
Polyketanils. Polymers protonated with Bronsted acid
Authors: Iwan Agnieszka , Kaczmarczyk Bozena , Kasperczyk Janusz , Jurusik Jan , Janeczek Henryk , Sek Danuta , mazurak Zbigniew 
Published: August 2006

AbstractNew luminescent materials—aromatic polyketanils (PKs) containing p‐phenylene and biphenylene linkages in the backbone and electron‐donating, side‐group substitutions—were synthesized via melt polycondensation with the goal of studying the interactions between the polymer chains (PKs), primary dopant [1,2‐(di‐2‐ethylhexyl)ester of 4‐sulfophthalic acid (PSA)], and secondary dopant [m‐cresol (MC)] with 1H NMR, 13C NMR, Fourier transform infrared (FTIR), ultraviolet–visible, and photoluminescence measurements. Spectral changes were observed for the PKs after primary and secondary doping, and they supported ionic‐ and hydrogen‐bond formation between the PKs and the PSA and MC, respectively. This specific interaction of the dopant with the host polymer influenced the PK properties, and the following observations were made: (1) HOMO/LUMO energy gap of the protonated PKs; (2) bathochromic/hypsochromic photoluminescence shifts observed after protonation with PSA; (3) a downfield chemical shift of the labile proton in the protonating agent OH group in the 1H NMR spectra of the protonated polymers; (4) a protonation decrease in the intensity of the CN stretching band in the FTIR spectrum; and (5) a spherulite‐like morphology, detected by atomic force microscopy and polarized optical microscopy. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 5645–5660, 2006
Burnout and psychiatric morbidity among physicians engaged in end‐of‐life care for cancer patients: a cross‐sectional nationwide survey in Japan
Authors: Asai Mariko , Morita Tatsuya , Akechi Tatsuo , Sugawara Yuriko , Fujimori Maiko , Akizuki Nobuya , Nakano Tomohito , Uchitomi Yosuke 
Published: August 2006

AbstractPurpose: To determine the prevalence of burnout and psychiatric morbidity among physicians engaged in end‐of‐life care for cancer patients in Japan and to explore associated factors related to end‐of‐life care.Methods: Questionnaires were mailed to 1436 Japanese clinical oncologists and palliative care physicians with a request to complete the Maslach Burnout Inventory (MBI), the General Health Questionnaire (GHQ‐12), and to report on individual factors, including confidence in patient care. High levels of burnout and psychiatric morbidity were identified using cut‐off scores of the MBI and GHQ‐12.Results: A total of 697 physicians returned the questionnaires (response rate, 49.6%). Twenty‐two percent of the respondents had a high level of emotional exhaustion, 11% had a high level of depersonalization, 62% had a low level of personal accomplishment, and 20% had psychiatric morbidity. Clinical oncologists showed a significantly higher psychiatric morbidity than palliative care physicians. Confidence in having sufficient time to communicate with patients was significantly associated with all the burnout subscales.Conclusions: A low level of personal accomplishment was relatively high among Japanese physicians compared with previous studies. Insufficient confidence in the psychological care of patients was associated with physician burnout rather than involvement in end‐of‐life care. Copyright © 2006 John Wiley & Sons, Ltd.
Screening childhood cancer survivors with the brief symptom inventory‐18: classification agreement with the symptom checklist‐90‐revised
Authors: Recklitis Christopher J. , Rodriguez Paola 
Published: August 2006

AbstractThe Brief Symptom Inventory‐18 (BSI‐18) is an 18‐item symptom checklist used as a brief distress screening in cancer and other medical patients. This study evaluated the validity of the BSI‐18 in a sample of 221 adult survivors of childhood cancers ages 18–55 (median = 26). Validity of the BSI‐18 was compared to the Symptom Checklist‐90‐Revised (SCL‐90‐R). Results indicated the BSI‐18 scales had acceptable internal consistency (alpha >0.80) and were highly correlated with the corresponding SCL‐90‐R subscales (correlations from 0.88 to 0.94). When subjects were classified as case positive (significantly distressed) using the BSI‐18 manual case‐rule, classification agreement with the SCL‐90‐R was poor as evidenced by low sensitivity (41.78%). An alternative BSI‐18 case‐rule previously developed for cancer patients using the General Severity Index (GSI; GSI t‐score ⩾57) demonstrated better sensitivity (83.54%). ROC analysis indicated the BSI‐18 had strong diagnostic utility relative to the SCL‐90‐R (AUC = 0.98) and several possible GSI cut‐off scores were evaluated. The optimal cut‐of score was a t‐score ⩾50 which had a sensitivity of 97.47% and a specificity of 85.21%. Results support use of the BSI‐18 with adult survivors of childhood cancer but indicate an alternative case‐rule must be used. Copyright © 2006 John Wiley & Sons, Ltd.
Behavioral risk factors among Black and White women newly diagnosed with breast cancer
Authors: Tercyak Kenneth P. , Davis Kimberly M. , Loffredo Christopher A. 
Published: August 2006

AbstractBackground: To determine the rates of three behavioral risk factors (depression symptoms, smoking, and drinking) among women newly diagnosed with breast cancer and to examine if the rates under investigation differed between Black and White women.Method: Subjects were 147 women (47% Black, 53% White) newly diagnosed with breast cancer and participating in an epidemiologic interview study conducted at two metropolitan area cancer centers in the same city. The epidemiologic interview included women's tobacco, alcohol, and drug use history, medical and family history, and depression symptoms.Results: Among all women in the sample, 33% reported clinically significant depression symptoms, 10% currently smoked cigarettes, and 57% currently drank alcohol. Seventy percent of women reported experiencing one or more behavioral risk factors, and White women were more likely than Black women to do so. After controlling for other demographic variables, White women were 50% more likely to report clinical symptoms of depression (odds ratio=1.55, 95% confidence interval=1.03, 2.30) and over two times more likely to report being current drinkers (odds ratio=2.19, 95% confidence interval=1.45, 3.30) than were Black women (p<0.05).Conclusions: The results suggest that certain behaviors of Black women may be associated with lower levels of self‐reported distress. These findings also suggest the need for further research to examine behavioral comorbidity among women with breast cancer, and the roles that race, ethnicity, and culture may play in their expression. Copyright © 2006 John Wiley & Sons, Ltd.
Using the theory of planned behavior to understand the determinants of exercise intention in patients diagnosed with primary brain cancer
Authors: Jones Lee W. , Guill Bebe , Keir Stephen T. , Carter Karen , Friedman Henry S. , Bigner Darell D. , Reardon David A. 
Published: August 2006

AbstractThe purpose of the present study was to examine the demographic, medical, and social cognitive determinants of exercise intentions in a institution‐based cohort of primary brain tumor patients. Using a cross‐sectional survey, 100 primary brain tumor patients completed a mailed survey that assessed medical and demographic characteristics, past exercise behavior using the Godin Leisure Time Exercise Questionnaire (GLTEQ), and social cognitive beliefs towards exercise using Aizen's theory of planned behavior (TPB; i.e. intention, perceived behavioral control, subjective norm, affective and instrumental attitude). Descriptive statistics indicated that participants had positive social cognitive beliefs towards exercise. In support of the tenets of the TPB, we found moderate to large (>0.40) positive correlations between the majority of TPB constructs. Moreover, the TPB constructs combined to explain 32% of the variance in exercise intentions with affective attitude (β = 0.24; p = 0.020) and perceived behavioral control (β = 0.36; p<0.001) being the most important determinants. Except past exercise behavior, medical and demographic variables were not consistently correlated with any TPB constructs. Finally, participant's gender and body mass index influenced the association between instrumental attitude and exercise intention with male and overweight/obese patients (⩾25 kg/m2) considering the health benefits of exercise to be more important than their female and normal weight (<25 kg/m2) counterparts. Information gained from this study suggests that the TPB is a useful framework to design and implement theoretically based interventions to promote exercise in primary brain cancer patients. Copyright © 2006 John Wiley & Sons, Ltd.
Current methodological approaches to the study of sleep disturbances and quality of life in adults with cancer: a systematic review
Authors: Berger Ann M. , Sankaranarayanan Jayashri , Watanabe‐Galloway Shinobu 
Published: August 2006

AbstractIn recent years, sleep disturbances and the health‐related quality of life (QOL) experienced by adults with cancer, during and after cancer treatment, have received increasing attention in the scientific literature. The purpose of this paper was to systematically review current methodological approaches to the study of sleep disturbances and QOL in adults with cancer. Databases were searched to identify longitudinal studies of adults with cancer that measured sleep disturbances and QOL in the past 10 years. The review was focused in five primary areas: trends in publication, measurement of sleep and QOL, study design, changes in sleep disturbances and QOL, and the level of this evidence. Of the 40 studies that met the authors' criteria for inclusion, 75% were descriptive in design and 25% were intervention studies. Studies on sleep and QOL among cancer patients have become more common since 2000, include a range of sample sizes and settings, use a variety of measures of sleep and QOL, and examine patients undergoing many types of cancer therapies. No programs of research have been developed in sleep disturbances and QOL in adults with cancer. The ‘evidence’ that can be drawn from such studies is obviously weak. Current approaches usually describe changes over time, but have not described whether a relationship exists between sleep disturbances and QOL in adults with cancer. Directions for future research are suggested. Copyright © 2006 John Wiley & Sons, Ltd.
Comparison of Primary Rat Hepatocyte Attachment to Collagen and Plasma‐Polymerised Allylamine on Glass
Authors: Dehili Chafika , Lee Pauline , Shakesheff Kevin M. , Alexander Morgan R. 
Published: August 2006

AbstractSummary: Cellular attachment to substrata is a crucial stage in cell culture and tissue engineering. Many cells including hepatocytes attach poorly to synthetic substrata and favour attachment to ECM proteins. Currently, cellular attachment to synthetic materials is often optimised by applying ECM protein coatings such as collagen. In this work, ppAAm was examined as an alternative coating method to collagen type‐I gel to promote attachment of primary rat hepatocytes to glass. XPS analysis was used to quantify the composition of the nitrogen containing ppAAm surfaces where the nitrogen is present in the form of amine, imine and possibly amide functionalities. Phase contrast microscopy and total cellular protein measurements indicated that hepatocyte attachment to glass was significantly improved by coating with ppAAm, collagen type‐I gel or collagen type‐I gel on ppAAm. In addition, cytochrome P450 activity and albumin secretion of hepatocytes cultured on ppAAm were similar to the levels observed in hepatocytes plated on collagen type‐I gel or collagen type‐I gel on ppAAm. In conclusion, the ppAAm coating was shown to improve the attachment of hepatocytes to glass while maintaining similar functionality to cells cultured on collagen type‐I gel.Phase contrast images of primary rat hepatocytes plated on collagen type‐I gel (top) and plasma polymerised allylamine (bottom) after 24 h in culture.magnified imagePhase contrast images of primary rat hepatocytes plated on collagen type‐I gel (top) and plasma polymerised allylamine (bottom) after 24 h in culture.
Inactivation of Bacteria by the Plasma Pencil
Authors: Laroussi Mounir , Tendero Claire , Lu Xinpei , Alla Sudhakar , Hynes Wayne L. 
Published: August 2006

AbstractSummary: A device capable of generating a relatively long cold plasma plume has recently been developed. The advantages of this device are: plasma controllability and stability, room temperature and atmospheric pressure operation, and low power consumption. These features are what is required from a plasma source to be used reliably in material processing applications, including the biomedical applications. In this communication we describe the device and we present evidence that it can be used successfully to inactivate Escherechia coli in a targeted fashion. More recent experiments have shown that this device inactivates other bacteria also, but these will be reported in the future.Photograph of a He plasma plume launched out of the plasma pencil.magnified imagePhotograph of a He plasma plume launched out of the plasma pencil.
Long loop prediction using the protein local optimization program
Authors: Zhu Kai , Pincus David L. , Zhao Suwen , Friesner Richard A. 
Published: August 2006

AbstractWe have developed an improved sampling algorithm and energy model for protein loop prediction, the combination of which has yielded the first methodology capable of achieving good results for the prediction of loop backbone conformations of 11 residue length or greater. Applied to our newly constructed test suite of 104 loops ranging from 11 to 13 residues, our method obtains average/median global backbone root‐mean‐square deviations (RMSDs) to the native structure (superimposing the body of the protein, not the loop itself) of 1.00/0.62 Å for 11 residue loops, 1.15/0.60 Å for 12 residue loops, and 1.25/0.76 Å for 13 residue loops. Sampling errors are virtually eliminated, while energy errors leading to large backbone RMSDs are very infrequent compared to any previously reported efforts, including our own previous study. We attribute this success to both an improved sampling algorithm and, more critically, the inclusion of a hydrophobic term, which appears to approximately fix a major flaw in SGB solvation model that we have been employing. A discussion of these results in the context of the general question of the accuracy of continuum solvation models is presented. Proteins 2006. © 2006 Wiley‐Liss, Inc.
Structural refinement of protein segments containing secondary structure elements: Local sampling, knowledge‐based potentials, and clustering
Authors: Zhu Jiang , Xie Li , Honig Barry 
Published: August 2006

AbstractIn this article, we present an iterative, modular optimization (IMO) protocol for the local structure refinement of protein segments containing secondary structure elements (SSEs). The protocol is based on three modules: a torsion‐space local sampling algorithm, a knowledge‐based potential, and a conformational clustering algorithm. Alternative methods are tested for each module in the protocol. For each segment, random initial conformations were constructed by perturbing the native dihedral angles of loops (and SSEs) of the segment to be refined while keeping the protein body fixed. Two refinement procedures based on molecular mechanics force fields — using either energy minimization or molecular dynamics — were also tested but were found to be less successful than the IMO protocol. We found that DFIRE is a particularly effective knowledge‐based potential and that clustering algorithms that are biased by the DFIRE energies improve the overall results. Results were further improved by adding an energy minimization step to the conformations generated with the IMO procedure, suggesting that hybrid strategies that combine both knowledge‐based and physical effective energy functions may prove to be particularly effective in future applications. Proteins 2006. © 2006 Wiley‐Liss, Inc.
Development, validation, and application of adapted PEOE charges to estimate pKa values of functional groups in protein–ligand complexes
Authors: Czodrowski Paul , Dramburg Ingo , Sotriffer Christoph A. , Klebe Gerhard 
Published: August 2006

AbstractFor routine pKa calculations of protein–ligand complexes in drug design, the PEOE method to compute partial charges was modified. The new method is applicable to a large scope of proteins and ligands. The adapted charges were parameterized using experimental free energies of solvation of amino acids and small organic ligands. For a data set of 80 small organic molecules, a correlation coefficient of r2 = 0.78 between calculated and experimental solvation free energies was obtained. Continuum electrostatics pKa calculations based on the Poisson–Boltzmann equation were carried out on a validation set of nine proteins for which 132 experimental pKa values are known. In total, an overall RMSD of 0.88 log units between calculated and experimentally determined data is achieved. In particular, the predictions of significantly shifted pKa values are satisfactory, and reasonable estimates of protonation states in the active sites of lysozyme and xylanase could be obtained. Application of the charge‐assignment and pKa‐calculation procedure to protein–ligand complexes provides clear structural interpretations of experimentally observed changes of protonation states of functional groups upon complex formation. This information is essential for the interpretation of thermodynamic data of protein–ligand complex formation and provides the basis for the reliable factorization of the free energy of binding in enthalpic and entropic contributions. The modified charge‐assignment procedure forms the basis for future automated pKa calculations of protein–ligand complexes. Proteins 2006; © 2006 Wiley‐Liss, Inc.
Impact of EGFR point mutations on the sensitivity to gefitinib: Insights from comparative structural analyses and molecular dynamics simulations
Authors: Liu Bing , Bernard Brandon , Wu Jian Hui 
Published: August 2006

AbstractEmergence of resistant mutations in drug targets represents a serious problem in the targeted chemotherapy. One challenging issue is to understand the atomic‐detailed effect of the mutation on the target. Another intriguing issue is how to predict specific mutations that would show up in the clinical setting, leading to drug resistance. By computational approaches, we have investigated structural, dynamics and energetic effects of a series of EGFR mutations identified from the lung cancer patients. We demonstrated mutation L858R caused gefitinib move closer to the hinge region, whereas T790M caused the ligand escape from the binding pocket. In particular, the T790M decreased the size of the hydrophobic slot formed by L718 and G796. This suggests that, to be effective against the T790M mutant, the inhibitors should avoid interactions with the hydrophobic slot. Mutations T790M, L858R, and their combinations are found to cause different conformational redistribution and to perturb the electrostatic potential at the ATP‐binding pocket. Normal mode analysis revealed the mutations resulted in changes in the correlated movements in the protein. In an attempt to develop a computational descriptor for predicting the functional effect of EGFR mutations, we have developed a Plarm algorithm, and the Plarm score was found to be an excellent predictor of the functional impact of six clinical relevant mutations in EGFR tyrosine kinase domains, including T790M, L858R, G719C, L861Q, T790M + L858R double mutant, and delL747–P753insS. The Plarm algorithm could be readily extended to investigate other drug targets. Proteins 2006. © 2006 Wiley‐Liss, Inc.
Structure determination of a new protein from backbone‐centered NMR data and NMR‐assisted structure prediction
Authors: Mayer K. L. , Qu Y. , Bansal S. , LeBlond P. D. , Jenney F. E. , Brereton P. S. , Adams M. W. W. , Xu Y. , Prestegard J. H. 
Published: August 2006

AbstractTargeting of proteins for structure determination in structural genomic programs often includes the use of threading and fold recognition methods to exclude proteins belonging to well‐populated fold families, but such methods can still fail to recognize preexisting folds. The authors illustrate here a method in which limited amounts of structural data are used to improve an initial homology search and the data are subsequently used to produce a structure by data‐constrained refinement of an identified structural template. The data used are primarily NMR‐based residual dipolar couplings, but they also include additional chemical shift and backbone‐nuclear Overhauser effect data. Using this methodology, a backbone structure was efficiently produced for a 10 kDa protein (PF1455) from Pyrococcus furiosus. Its relationship to existing structures and its probable function are discussed. Proteins 2006. © 2006 Wiley‐Liss, Inc.