bluuebunny/crossref_metadata_2025_split huggingface dataset:
Rubber networks containing unattached macromolecules. IV. Stress relaxation in end‐linked polybutadiene with unattached styrene‐butadiene copolymer
Authors: Nelb Gary W. , Pedersen Sven , Taylor Carl R. , Ferry John D. 
Published: August 2005

AbstractStress relaxation has been studied in networks of dihydroxy‐terminated polybutadiene (mostly cis:trans:vinyl = 34:40:26) crosslinked by triphenyl methane‐4,4′,4″‐triisocyanate and containing about 9.5% by weight of unattached linear random styrene‐butadiene copolymer with various molecular weights (from 1.4 to 3.3 × 105) and with styrene content and butadiene microstructure chosen to match the average solubility parameter of the end‐linked network. Stress relaxation measurements were made also on networks containing no unattached species and containing 9.3% hydrocarbon oil, and on the various uncrosslinked linear polymers. The stretch ratio was 1.25 and the Young's relaxation modulus was calculated from the neo‐Hookean stress‐strain relation. For the uncrosslinked linear polymers, the relaxation modulus E11(t) corresponds to a rather narrow distribution of relaxation times whose magnitudes were approximately proportional to the 3.4 power of viscosity‐average or weight‐average molecular weight; for one polymer, the time dependence agreed closely with the prediction of the Doi‐Edwards theory modified for a small degree of molecular weight distribution. The disengagement times calculated from the Doi‐Edwards theory as modified by Graessley appeared to be of the correct order of magnitude. The contribution of the unattached species in the networks E1(t) was calculated by difference; after multiplication by (1−v)−1, where v2 is the volume fraction of network, and correction for the difference in monomeric friction coefficient associated with the difference in fractional free volume in the two environments, E1(t) was compared with E11(t) for each linear polymer. The relaxation was slower in the network than in the uncrosslinked polymer by about an order of magnitude, but the form of the relaxation modulus was similar in both environments except for two linear polymers for which the relaxation in the network became very much slower at long times. This behavior appeared to be correlated with a broader molecular weight distribution.
Polyimidines. VIII. Condensation of 3,5‐dibenzylidenepyromellitide‐1,7‐dithione with m‐xylylenediamine
Authors: Johnson C. Greg , Cassidy Patrick E. 
Published: August 2005

AbstractA new pyromellitimidine‐forming monomer, 3,5‐dibenzylidenepyromellitide‐1,7‐dithione, was synthesized by thionation of 3,5‐dibenzylidenepyromellitide using phosphorus pentasulfide in boiling chloro‐ or bromobenzene. Polymerization of this monomer with m‐xylylenediamine (MXDA) in chlorobenezene at 95°C afforded poly(dihydroxydibenzylpyromellitimidinethione) with inherent viscosities of 0.23–0.51 dL/g in yields from 73 to 84%. Subsequent dehydration was accomplished by thermal methods or in a polar aprotic solvent such as dimethylformamide (DMF) using acid catalyst. Hydrated and dehydrated polymers were soluble in N‐methyl‐2‐pyrrolidinone (NMP), m‐cresol, and dioxane, and partially soluble in chloroform. Very brittle films could be cast from NMP solution. Thermogravimetric analysis of the dehydrated polymer showed a 10% weight loss in nitrogen atmosphere at 460°C
Synthesis and properties of polyesters of isomeric poly(oxynaphthyleneoxy‐2‐bromoterephthaloyl)s
Authors: Jin Jung‐Il , Choi E‐Joon , Kang Chung‐Seock , Chang Jin‐Hae 
Published: August 2005

AbstractA series of aromatic polyesters were prepared from 2‐bromoterephthalic acid and naphthalenediol isomers. Only the polymers obtained from 1,4‐, and 1,5‐ and 2,6‐naphthalenediols were thermotropic nematogens and those from bent naphthalenediols were not liquid crystalline. Only the polyesters derived from 1,4‐, 1,5‐, and 2,6‐naphthalenediols were semicrystalline. The melting temperatures ranged from 319 to 374°C depending on the structure of naphthalenediol moiety. The glass transition temperature, Tg, ranged from 95 to 168°C. TGA studied revealed that the polyesters have fairly good thermal stability
NMR studies of the thermal decomposition and branching reactions of aromatic esters
Authors: Ting Su‐Jen , Noggle J. H. 
Published: August 2005

AbstractPoly(chlorophydroquinone terephthalate) is an aromatic polyester containing mainly chlorohydroquinone and terephthalate. Thermal stability of this aromatic polyester has been a problem during the processing. In order to characterize the melt reactions of this polyester, the thermal degradation of the model compound chlorohydroquinone dibenzoate was studied. The chlorohydroquinone dibenzoate was characterized by high resolution 13C‐NMR. All experiments for studyng degradation of chlorohydroquinone dibenzoate were designed to test the following environmental parameters: (1) atmosphere, (2) temperature, (3) time, (4) additives, (5) container material. The analysis of the degradation products were carried out mainly using NMR; in some cases GC/MS and HPLC were also used to aid in separation and identification of the degradation products. The major degradation products produced in various experimental conditions were identified as chlorohydroquinone benzoates, hydroquinone dibenzoate, dichlorohydroquinone dibenzoate, 9‐fluorenone, benzoic acid, Fries products, and hydrogen chloride
13C‐NMR spectroscopic analysis of vinyl groups in styrene–divinylbenzene networks
Authors: Periyasamy M. , Ford Warren T. , McEnroe Frank J. 
Published: August 2005

Abstractp‐Divinylbenzene (DVB) 13C‐labeled at the methine carbon of the vinyl group was copolymerized in suspension with styrene at 70, 70–95, and 135–155°C using 2,2′‐azobisisobutyronitrile (AIBN) as the initiator. The number of unreacted vinyl groups in each copolymer was determined by 13C CP–MAS NMR analysis of solid samples, direct polarization 13C‐NMR analysis of CDCl3‐swollen gels, and bromination. Results from the three methods agree methods agree qualitatively. Even the 1% DVB‐crosslinked networks contained 40% unreacted DVB‐vinyl groups when prepared by high conversion polymerization at 70°C and 16% unreacted DVB‐vinyl groups when polymerization was finished at 95°C. The analyses were also applied to some commercial crosslinked polystyrenes. Every sample examined contained pendent vinyl groups
Characterization and thermal degradation studies on polyaniline‐intercalated montmorillonite nanocomposites prepared by a solvent‐free mechanochemical route
Authors: Yoshimoto Shoji , Ohashi Fumihiko , Kameyama Tetsuya 
Published: August 2005

AbstractPolyaniline (PANI)‐montmorillonite (MMT) nanocomposites were prepared by direct intercalation of aniline molecules into MMT galleries, followed by in situ polymerization within the nano‐interlamellar spaces under solvent‐free conditions. The basal spacing of aniline‐intercalated MMT increased gradually up to 1.5 nm with increasing amounts of aniline loaded. This result suggests that aniline molecules were adsorbed by MMT clay and that intercalated aniline likely located perpendicular to the silicate sheets. After polymerization, X‐ray diffraction and Fourier transform infrared analyses confirmed the successful synthesis of PANI chains between the MMT nano‐interlayers. The scanning electron microscopy images indicated that the surface morphologies of PANI–MMTs were strongly different depending on the PANI content. The electrical conductivities of PANI nanocomposite particles in pressed pellets ranged in the order of between 10−3 and 10−2 S/cm. UV–vis spectroscopy and doping level measurement were further used to discuss the conductivities of nanocomposites. The thermal stabilities of PANI–MMT nanocomposites were examined by using thermogravimetric‐differential thermal analysis and derivative thermogravimetric analysis, and both analyses consequently demonstrated the improved thermal stabilities of the PANI chains in the nanocomposites as compared to pure PANI. The thermal stabilities of resulting nanocomposites were strongly related to the PANI content, which increased as the PANI content decreased in the nanocomposites. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 43: 2705–2714, 2005
Spin‐density functional theory: Some open problems and application to inhomogeneous Heisenberg models
Authors: Capelle K. , Líbero Valter L. 
Published: August 2005

AbstractSpin‐density functional theory (SDFT) is the most widely implemented and applied formulation of density functional theory. However, it is still finding novel applications, and occasionally encounters unexpected problems. In this article, we first briefly describe a few of the latter, related to issues such as nonuniqueness, noncollinearity, and currents. We then turn to an example of the former, namely SDFT for the Heisenberg model. It is shown that time‐honored concepts of Coulomb DFT, such as the local‐density approximation, can be applied to this (and other) model Hamiltonians, as well, once the concept of “density” has been suitably reinterpreted. Local‐density‐type approximations for the inhomogeneous Heisenberg model are constructed. Numerical applications to finite‐size and impurity systems demonstrate that DFT is a computationally efficient and reasonably accurate alternative to conventional methods of statistical mechanics for the Heisenberg model. © 2005 Wiley Periodicals, Inc. Int J Quantum Chem, 2005
Image retrieval with principal component analysis for breast cancer diagnosis on various ultrasonic systems
Authors: Huang Y.‐L. , Kuo S.‐J. , Chang C.‐S. , Liu Y.‐K. , Moon W. K. , Chen D.‐R. 
Published: August 2005

AbstractObjectivesWe present a computer‐aided diagnostic (CAD) system with textural features and image retrieval strategies for classifying benign and malignant breast tumors on various ultrasonic systems. Effective applications of CAD have used different types of texture analysis. Nevertheless, most approaches performed in a specific ultrasonic machine do not indicate whether the technique functions satisfactorily for other ultrasonic systems. This study evaluated a series of pathologically proven breast tumors using various ultrasonic systems.MethodsAltogether, 600 ultrasound images of solid breast nodules comprising 230 malignant and 370 benign tumors were investigated. All ultrasound images were acquired from four diverse ultrasonic systems. The suspicious tumor area in the ultrasound image was manually chosen as the region‐of‐interest (ROI) subimage. Textural features extracted from the ROI subimage are supported in classifying the breast tumor as benign or malignant. However, the textural feature always behaves as a high‐dimensional vector. In practice, high‐dimensional vectors are unsatisfactory at differentiating breast tumors. This study applied the principal component analysis (PCA) to project the original textural features into a lower dimensional principal vector that summarized the original textural information. The image retrieval techniques were employed to differentiate breast tumors, according to the similarities of the principal vectors. The query ROI subimages were identified as malignant or benign tumors according to characteristics of retrieved images from the ultrasound image database.ResultsUsing the proposed CAD system, historical cases could be directly added into the database without a retraining program. The area under the receiver–operating characteristics curve for the system was 0.970 ± 0.006.ConclusionThe CAD system identified solid breast nodules with comparatively high accuracy in the different ultrasound systems investigated. Copyright © 2005 ISUOG. Published by John Wiley & Sons, Ltd.
The nuclear actin‐related protein Act3p/Arp4p is involved in the dynamics of chromatin‐modulating complexes
Authors: Sunada Rie , Görzer Irene , Oma Yukako , Yoshida Takahito , Suka Noriyuki , Wintersberger Ulrike , Harata Masahiko 
Published: August 2005

AbstractChromatin remodelling and histone‐modifying complexes govern the modulation of chromatin structure. While components of these complexes are diverse, nuclear actin‐related proteins (Arps) have been repeatedly found in these complexes from yeast to mammals. In most cases, Arps are required for functioning of the complexes, but the molecular mechanisms of nuclear Arps have as yet been largely unknown. The Arps and actin, sharing a common ancestor, are supposed to be highly similar in the three‐dimensional structure of their core regions, including the ATP‐binding pocket. The Arp Act3p/Arp4p of Saccharomyces cerevisiae exists within the nucleus, partly as a component of several high molecular mass complexes, including the NuA4 histone acetyltransferase (HAT) complex, and partly as uncomplexed molecules. We observed that mutations in the putative ATP‐binding pocket of Act3p/Arp4p increased its concentration in the high molecular mass complexes and, conversely, that an excess of ATP or ATPγS led to the release of wild‐type Act3p/Arp4p from the complexes. These results suggest a requirement of ATP binding by Act3p/Arp4p for its dissociation from the complexes. In accordance, a mutation in the putative ATP binding site of Act3p/Arp4p inhibited the conversion of the NuA4 complex into the smaller piccoloNuA4, which does not contain Act3p/Arp4p and exhibits HAT activity distinct from that of NuA4. Although the in vitro binding activity of ATP by recombinant Act3p/Arp4p was found to be rather weak, our observations, taken together, suggest that the ATP‐binding pocket of Act3p/Arp4p is involved in the function of chromatin modulating complexes by regulating their dynamics. Copyright © 2005 John Wiley & Sons, Ltd.
Cloning, sequencing and application of the LEU2 gene from the sour dough yeast Candida milleri
Authors: Turakainen Hilkka , Korhola Matti 
Published: August 2005

AbstractWe have cloned by complementation in Saccharomyces cerevisiae and sequenced a LEU2 gene from the sour dough yeast Candida milleri CBS 8195 and studied its chromosomal location. The LEU2 coding sequence was 1092 nt long encoding a putative β‐isopropylmalate dehydrogenase protein of 363 amino acids. The nucleotide sequence in the coding region had 71.6% identity to S. cerevisiae LEU2 sequence. On the protein level, the identity of C. milleri Leu2p to S. cerevisiae Leu2p was 84.1%. The DNA sequence of the C. milleri LEU2 gene was submitted to GenBank and assigned Accession No. AY571337. The CmLEU2 DNA probe hybridized to one to three chromosomal bands and two or three BamHI restriction fragments in C. milleri but did not give any signal to chromosomes or restriction fragments of C. albicans, S. cerevisiae, S. exiguus or Torulaspora delbrueckii. Using CmLEU2 probe for DNA hybridization makes it easy to quickly identify C. milleri among other sour dough yeasts. Copyright © 2005 John Wiley & Sons, Ltd.
A rapid and simple procedure for high‐efficiency lithium acetate transformation of cryopreserved Schizosaccharomyces pombe cells
Authors: Suga Minoru , Hatakeyama Toyomasa 
Published: August 2005

AbstractA rapid, simple, convenient, and highly efficient transformation of the fission yeast Schizosaccharomyces pombe has been developed. Freezing fission yeast cells in glycerol, a permeating cryoprotectant, with lithium acetate improved remarkably the transformation efficiency by one to two orders of magnitude. The optimum concentration of glycerol was found to be 30%, which is higher than that (10–15%) in the conventional cryopreservation of yeast cells. Glycerol not only played a role in cryopreserving the competent cells but also improved the transformation efficiency of the process. The thawed cell suspension with glycerol and lithium acetate was immediately mixed with carrier DNA, plasmid DNA and polyethylene glycol. Next, the mixture was heat shocked and directly spread on a selection plate. This simple procedure yielded more than 106 transformants/µg plasmid DNA, reducing the time required to only 20 min in total, including the thawing time. Furthermore, the frozen competent cells were stored long‐term for more than 3 months without any significant loss of efficiency. Copyright © 2005 John Wiley & Sons, Ltd.
Hepatectomy as Treatment of Choice for Hepatocellular Carcinoma in Elderly Cirrhotic Patients
Authors: Ferrero Alessandro , Viganò Luca , Polastri Roberto , Ribero Dario , Tesoriere Roberto Lo , Muratore Andrea , Capussotti Lorenzo 
Published: August 2005

AbstractIn recent decades liver resection has become a safe procedure; however, the outcome of hepatectomies in aged cirrhotic patients is often uncertain. To elucidate early and long‐term outcomes of hepatectomy for HCC in the elderly, we studied 241 cirrhotic patients who underwent liver resection for HCC between 1985 and 2003. According to their age at the time of surgery, patients were divided into two groups: aged > 70 years (64 patients) and aged ≤ 70 years (177 patients). Operative mortality was 3.1% in the elderly and 9.6% in the younger group (p = 0.113). Postoperative morbidity and liver failure rates were higher in the younger group (42.4% versus 23.4%, p = 0.0073; 12.9% versus l.6%, p = 0.0065). Five‐year survival rates are 48.6% in the elderly group and 32.3% in the younger group (p = 0.081). Considering only radical resections in Child‐Pugh A patients, survival remains similar in the two groups (p = 0.072). Disease‐free survival is not different in the two groups. A survival analysis performed according to the tumor diameter shows a better survival for elderly Child‐Pugh A patients with HCC larger than 5 cm radically resected (50.8% versus 16.1% 5‐year survival, p = 0.034). In univariate analysis, tumor size is not a prognostic factor in the elderly, whereas younger patients with large tumors have a worse outcome. Age by itself is not a contraindication for surgery, and selected cirrhotic patients with HCC who are 70 years of age or older could benefit from resection, even in the presence of large tumors. Long‐term results of liver resections for HCC in the elderly may be even better than in younger patients.
Prevalence of Thyroid Nodules and Carcinomas in Patients Operated on for Renal Hyperparathyroidism: Experience with 339 Consecutive Patients and Review of the Literature
Authors: Seehofer Daniel , Rayes Nada , Klupp Jochen , Nüssler Natascha C. , Ulrich Frank , Graef Klaus‐Jürgen , Schindler Ralph , Steinmüller Thomas , Frei Ulrich , Neuhaus Peter 
Published: August 2005

AbstractThe association between renal hyperparathyroidism (HPT) and differentiated thyroid carcinoma is discussed. To determine the prevalence and potential risk factors, we performed a retrospective analysis of our patients (1998–2004) and compared the data with the data from other surgical and autopsy studies. At our hospital, a total of 347 parathyroidectomies in 339 patients with renal HPT were performed. Most patients underwent preoperative ultrasound investigation of the thyroid gland and, if indicate, thyroid scintigraphy. Intraoperatively, both thyroid lobes were mobilized and palpated. Detected thyroid nodules were adequately resected and investigated histologically. A systematic analysis of the international literature was performed using the PubMed/MEDLINE system to identify publications on the prevalence of papillary thyroid carcinoma (PTC) in patients with renal HPT and in the overall population. Altogether, 133 patients (39.2%) underwent simultaneous thyroid surgery. The initial operation was hemithyroidectomy in 55 (16.2%), Dunhill operation in 36 (10.6%), unilateral subtotal resection in 17 (5.0%), bilateral subtotal resection in 5 (1.5%), and enucleation of a thyroid nodule in 18 (5.3%). A PTC was found in 8 of 339 patients (2.4%) and a follicular thyroid carcinoma in 1. Among 311 patients with primary cervical operation, 6 (1.9%) had a papillary thyroid carcinoma. All papillary tumors were classified as pT1 with a diameter of 1 to 12 mm; three were bifocal, and only one patient had positive lymph nodes. None of the analyzed factors showed a significant correlation with the occurrence of thyroid carcinoma. Depending on the screening method, the prevalence of occult PTC in European autopsy studies ranged from 5% to 9% and was markedly higher in almost all studies than in the present one. The prevalence of PTC in the present study makes an etiologic association between renal HPT and PTC unlikely. The clinical significance of these tumors remains unclear becauses all incidental tumors were small. However, if easily and safely feasible, relevant thyroid nodules should be removed during parathyroid surgery.
Prospective Randomized Comparison between a New Mattress Technique and Cattell (duct‐to‐mucosa) Pancreaticojejunostomy for Pancreatic Resection
Authors: Langrehr Jan M. , Bahra Marcus , Jacob Dietmar , Glanemann Matthias , Neuhaus Peter 
Published: August 2005

AbstractThe majority of lethal complications after pancreatic head resection are due to septic complications after leakage from the pancreatojejunostomy. Especially the smooth pancreatic remnant is prone to develop parenchymal leaks from shear forces applied during tying of the sutures. We developed a new mattress technique that avoids such shear forces, and we compared this method to the standard Cattell (duct‐to‐mucosa) technique. A total of 113 patients undergoing standard pancreatic head resection were prospectively randomized to receive either the standard Cattell anastomosis (n = 56) or the new mattress technique (n = 57). All patients were evaluated for surgical and medical complications until discharge. Primary diagnosis and further demographic data compared well between the groups. The time to perform the mattress anastomosis was significantly shorter (15 vs. 22 minutes; p < 0.0001). The incidence of complications at the pancreatojejunostomy, and the length of hospital stay and survival were not significantly different between the two groups; however, a trend toward more reoperations was noted in the Cattell group (10 vs. 5; p < 0.097). The new mattress technique is simple, and our data show that the two techniques yield similar incidences of complications. Therefore the mattress technique for pancreatojejunostomy seems to be safe and is, in our opinion, well suitable for training schedules in pancreatic surgery.
Analgesic efficacy and safety of intravenous paracetamol (acetaminophen) administered as a 2 g starting dose following third molar surgery
Authors: Juhl Gitte I. , Norholt Sven E. , Tonnesen Else , Hiesse‐Provost Odile , Jensen Troels S. 
Published: August 2005

AbstractBackground The recommended dose for intravenous (IV) paracetamol injection in adults is 1 g, however pharmacokinetic and pharmacodynamic findings suggest that a better analgesia could be obtained with a 2 g starting dose.Methods A single‐centre, randomised, double‐blind, placebo‐controlled, 3‐parallel group study was performed to demonstrate the analgesic efficacy and safety of IV paracetamol 2 g. Following third molar surgery, patients reporting moderate to severe pain received a single 15‐min infusion of either IV paracetamol 2 g, IV paracetamol 1 g or placebo. Efficacy and safety were evaluated over 8 h. Laboratory tests were performed before and 48 h after drug administration.Results Two hundred and ninety seven patients (132 = IV paracetamol 2 g; 132 = IV paracetamol 1 g; 33 = placebo) were randomised and completed the study. The summed pain relief over 6 h (TOTPAR6) was significantly superior with IV paracetamol 2 g as compared to IV paracetamol 1 g and placebo (p < 0.0001). Pain relief scores of IV paracetamol 2 g were significantly superior to IV paracetamol 1 g and to placebo from T30′ to T8h (p < 0.0001). Median duration of analgesia was significantly longer following IV paracetamol 2 g compared to IV paracetamol 1 g and placebo (p < 0.0001). Adverse events occurred with the same frequency in the 3 treatment groups. No clinically significant changes from baseline were observed for vital signs or laboratory tests.Conclusion The analgesic efficacy of a 2 g starting dose of IV paracetamol was superior over the recommended dose of 1 g in terms of magnitude and duration of analgesic effect for postoperative pain following third molar surgery, with no significant difference between groups regarding safety.