bluuebunny/crossref_metadata_2025_split huggingface dataset:
Copolymers of 2,5‐bis[(4‐methoxyphenyl) oxycarbonyl]styrene with styrene and methyl methacrylate: Synthesis, monomer reactivity ratios, thermal properties, and liquid crystalline behavior
Authors: Zhao Yong‐feng , Yi Yi , Fan Xinghe , Chen Xiaofang , Wan Xinhua , Zhou Qi‐Feng 
Published: May 2005

AbstractCopolymers of a liquid crystalline monomer, 2,5‐bis[(4‐methoxyphenyl)oxycarbonyl]styrene (MPCS), with St and MMA were prepared by free radical polymerization at low conversion in chlorobenzene with 2,2′‐azobisisobutyronitrile (AIBN) as initiator. The copolymers of poly(MPCS‐co‐St) and poly(MPCS‐co‐MMA) were characterized by 1H NMR and GPC. The monomer reactivity ratios were determined by using the extended Kelen–Tudos (EKT) method. Structural parameters of the copolymers were obtained from the possibility statistics and monomer reactivity ratios. The influence of MPCS content in copolymers on the glass transition temperatures of copolymers was investigated by DSC. The thermal stabilities of the two copolymer systems increased with an increase of the molar fraction of MPCS in the copolymers. The liquid crystalline behavior of the copolymers was also investigated using DSC and POM. The results revealed that the copolymers with high MPCS molar contents exhibited liquid crystalline behaviors. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 2666–2674, 2005
Matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry study on copolymers obtained by the alternating copolymerization of bis(γ‐lactone) and epoxide with potassium tert‐butoxide
Authors: Zhang Chenxi , Ochiai Bungo , Endo Takeshi 
Published: May 2005

AbstractOligomer samples obtained by the anionic copolymerization of a bis(γ‐lactone), 2,8‐dioxa‐1‐methylbicyclo[3.3.0]octane‐3,7‐dione (1), and glycidyl phenyl ether with potassium tert‐butoxide have been analyzed by matrix‐assisted laser desorption/ionization time‐of‐flight (MALDI‐TOF) mass spectrometry. The MALDI‐TOF mass spectra of these cooligomers show well‐resolved signals that can be reliably assigned to linear, alternating cooligomers that have carboxylate chain ends or alkoxide chain ends and cyclic ones. The formation of these three series of cooligomers suggests that the polymerization process involves concomitant intermolecular transesterification and intramolecular back‐biting. The intramolecular back‐biting reaction causes the formation of cyclic cooligomers, whereas the intermolecular transesterification causes the reduction of the molecular weight and the transformation of the alkoxide active chain end into a carboxylate chain end. The MALDI‐TOF mass spectrometry study has shown that an excess of monomer 1 enhances the selectivity of propagation by increasing the probability of the attack of the alkoxide chain end to 1. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 2643–2649, 2005
Synthesis and swelling behavior of comb‐type grafted hydrogels by reversible addition–fragmentation chain transfer polymerization
Authors: Liu Qunfeng , Zhang Ping , Lu Mangeng 
Published: May 2005

AbstractThe comb‐type grafted hydrogels poly(N‐isopropylacrylamide)‐g‐poly(N‐isopropylacrylamide) (PNIPAM‐g‐PNIPAM) and poly(acrylic acid)‐g‐poly(N‐isopropylacrylamide) (PAAc‐g‐PNIPAM) were prepared by reversible addition–fragmentation chain transfer polymerization. A macromolecular chain‐transfer agent was prepared first. Then, hydrogels were obtained by a reaction with a comonomer (N‐isopropylacrylamide or acrylic acid) in the presence of N,N‐methylenebisacrylamide as a crosslinker. The equilibrium swelling ratios and the swelling and deswelling kinetics of PNIPAM‐g‐PNIPAM were measured. The effects of the chain length and amount on the swelling behavior were investigated. The deswelling mechanism was illustrated. Meanwhile, the PAAc‐g‐PNIPAM hydrogel was used to confirm the versatility of this novel method. It was prepared in an alcoholic medium, whereas hydrogen‐bonding complexes formed in 1,4‐dioxane, which was chosen as the reaction medium for the PNIPAM‐g‐PNIPAM hydrogel. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 2615–2624, 2005
Self‐assembly of GaAs holed nanostructures by droplet epitaxy
Authors: Wang Zhiming M. , Holmes Kyland , Shultz John L. , Salamo Gregory J. 
Published: May 2005

AbstractWe report on Ga nano‐droplets on GaAs(100) that are not stable under arsenic flux. Spontaneous evolution in shape leads to many interesting GaAs nanostructures. GaAs nano‐crystals shaped like lighted candles and square‐holed round coins are observed under different growth conditions. The underlying physics of the formation of these interesting nano‐structures can be understood in terms of GaAs growth under a uniform arsenic flux and a non‐uniform Ga supply from the Ga nano‐droplets. These novel shaped GaAs nanostructures, in an AlGaAs matrix, offer promising applications in optoelectronics. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Transport of excitation energy in a molecular aggregate. VIII. Numerical simulation of exciton processes in thylakoid membrane
Authors: Panda Anirban , Datta Sambhu N. 
Published: May 2005

AbstractWe investigate the exciton dynamics in a molecular crystal. The dynamics is based on the exciton Hamiltonian, the phonon Hamiltonian, and the exciton–phonon interaction linear in phonon coordinates. Using the interaction picture, expressions were previously obtained for the rate of coherent migration of the exciton clothed by phonons, and the rate of incoherent or hopping motion. In this work we derive an expression for the clothed exciton propagator, which permits an explicit calculation of the hopping rate. Thus, the rates of exciton generation, coherent transfer, and hopping are determined completely from theory. These velocity constants, along with the experimental fluorescence decay constants and reaction rate constants for the excited molecules, are used to write a generalized master equation that describes the rate of change of exciton population at each site. The master equation can be numerically solved by using a time step of the order of a few femtoseconds, while the excited‐state reactions and exciton transfer occur in the picosecond scale. Exciton dynamics is numerically simulated for a simple model of thylakoid membrane in green plants. The model is based on the known characteristics of thylakoid architecture. The membrane is divided into 97 zones, each zone in the bulk containing 1,442 chlorophylls, one P700, and one P680. The latter two pigments are randomly placed in each zone, while keeping their distance between 55 and 60 Å. This accounts for the randomness in orientation. The disorder of the chlorophyll molecules within the domains of photosystems is neglected. Our findings are as follows. On average, about 6 million photons within the range of 655–681 nm pass through a membrane in 1 s. About 2.3% of incident photons are absorbed by the membrane chlorophyll molecules. For an excitation bandwidth of 70–175 cm−1, the coherent transfer rate between two adjacent molecules is 1.138 ± 0.488 ps−1. Because the Debye frequency is expected to be much smaller, the slow phonon limit applies. The exciton–phonon coupling constant that can be determined from the transition dipole–transition dipole interaction model leads to a hopping rate of 0.088 ps−1 at 300 K. A steady state is effectively achieved for each zone in the bulk in ∼5 ns. After a period of 50 ns, P700 and P680 in average trap at the rate of 650–702 and 629–679 excitons per second, respectively. The average rate of charge separation and subsequent reactions of each excited photosystem varies as 592–639 per second for PSI and 630–680 per second for PSII. These numbers lead to a reasonable estimate for the amount of glucose produced in each square meter of leaf area in a day. © 2005 Wiley Periodicals, Inc. Int J Quantum Chem, 2005
Quadratic Padé approximants and the intruder state problem of multireference perturbation methods
Authors: Perrine Trilisa M. , Chaudhuri Rajat K. , Freed Karl F. 
Published: May 2005

AbstractSimple and quadratic Padé resummation methods are applied to high‐order series from multireference many‐body perturbation theory (MR‐MBPT) calculations using various partitioning schemes (Møller–Plesset, Epstein–Nesbet, and forced degeneracy) to determine their efficacy in resumming slowly convergent or divergent series. The calculations are performed for the ground and low‐lying excited states of (i) CH2, (ii) BeH2 at three geometries, and (iii) Be, for which full configuration interaction (CI) calculations are available for comparison. The 49 perturbation series that are analyzed include those with oscillatory and monotonic divergence and convergence, including divergences that arise from either frontdoor or backdoor intruder states. Both the simple and quadratic Padé approximations are found to speed the convergence of slowly convergent or divergent series. However, the quadratic Padé method generally outperforms the simple Padé resummation. © 2005 Wiley Periodicals, Inc. Int J Quantum Chem, 2005
The surface chemistry of heterogeneous catalysis: Mechanisms, selectivity, and active sites
Authors: Zaera Francisco 
Published: May 2005

AbstractThe role of chemical kinetics in defining the requirements for the active sites of heterogeneous catalysts is discussed. A personal view is presented, with specific examples from our laboratory to illustrate the role of the chemical composition, structure, and electronic properties of specific surface sites in determining reaction activity and selectivity. Manipulation of catalytic behavior via the addition of chemical modifiers and by tuning of the reaction conditions is also introduced. © 2005 The Japan Chemical Journal Forum and Wiley Periodicals, Inc. Chem Rec 5: 133–144; 2005: Published online in Wiley InterScience (www.interscience.wiley.com) DOI 10.1002/tcr.20040
Monolayer‐derivative functionalization of non‐oxidized silicon surfaces
Authors: Shirahata Naoto , Hozumi Atsushi , Yonezawa Tetsu 
Published: May 2005

AbstractThis article describes a variety of monolayers anchored directly onto silicon surfaces without an oxide interlayer, their formation mechanisms, their technological applications, and our personal views on the future prospects for this field. The chemical modification of non‐oxidized silicon surfaces utilizing monolayers was first reported in 1993. The basic finding that a non‐oxidized silicon surface could be neutralized with alkyl chains through direct covalent linkage, i.e., silicon–carbon, has offered chemical scientists ease of handling even in an ambient environment and, thus, research has been predictably focused on forming anti‐stiction coating films for nano‐ and micro‐electromechanical systems (NEMS/MEMS). Such surface reforming has also been achieved by using other monolayers, which form interfacial bonds, e.g., silicon–nitrogen and silicon–oxygen. The resultant monolayer surfaces are useful for silicon‐based applications including molecular electron transfer films, monolayer templates, molecular insulators, capsulators, and bioderivatives. Such monolayers are applicable not only for surface modification, but also for manipulating individual nanomaterials. By modifying the terminal groups of monolayers with nanomaterials including nanocrystals and biomolecules, the nanomaterials can remarkably be immobilized directly onto non‐oxidized silicon surfaces based on the formation mechanisms of the monolayer. Such immobilizations will revolutionize the analysis of the specific features and capabilities of individual nanomaterials. Furthermore, the path will be opened for the development of more advanced monolayer‐derived chip technology. To achieve this goal, it is extremely important to thoroughly understand the functionalization processes on silicon, since the resultant internal structures and properties of monolayer‐derivative silicon may strongly depend on their course of formation. © 2005 The Japan Chemical Journal Forum and Wiley Periodicals, Inc. Chem Rec 5: 145–159; 2005: Published online in Wiley InterScience (www.interscience.wiley.com) DOI 10.1002/tcr.20041
Dual substrate recognition of aminotransferases
Authors: Hirotsu Ken , Goto Masaru , Okamoto Akihiro , Miyahara Ikuko 
Published: May 2005

AbstractPyridoxal 5′‐phosphate‐dependent aminotransferases reversibly catalyzes the transamination reaction in which the α‐amino group of amino acid 1 is transferred to the 2‐oxo acid of amino acid 2 (usually 2‐oxoglutarate) to produce the 2‐oxo acid of amino acid 1 and amino acid 2 (glutamate). An aminotransferase must thus be able to recognize and bind two kinds of amino acids (amino acids 1 and 2), the side chains of which are different in shape and properties, from among many other small molecules. The dual substrate recognition mechanism has been discovered based on three‐dimensional structures of aromatic amino acids, histidinol phosphate, glutamine : phenylpyruvate, acetylornithine, and branched‐chain amino acid aminotransferases. There are two representative strategies for dual substrate recognition. An aromatic amino acid aminotransferase prepares charged and neutral pockets for acidic and aromatic side chains, respectively, at the same place by a large‐scale rearrangement of the hydrogen‐bond network caused by the induced fit. In a branched‐chain aminotransferase, the same hydrophobic cavity implanted with hydrophilic sites accommodates both hydrophobic and acidic side chains without side‐chain rearrangements of the active‐site residues, which is reminiscent of the lock and key mechanism. Dual substrate recognition in other aminotransferases is attained by combining the two representative methods. © 2005 The Japan Chemical Journal Forum and Wiley Periodicals, Inc. Chem Rec 5: 160–172; 2005: Published online in Wiley InterScience (www.interscience.wiley.com) DOI 10.1002/tcr.20042
A study of PIXE continuum polarization properties
Authors: Potiriadis C. , Karydas A. G. , Zarkadas Ch. , Clouvas A. 
Published: May 2005

AbstractThe continuum radiation emitted after the proton bombardment of a solid or gaseous target can be described mainly by three mechanisms: the secondary electron bremsstrahlung (SEB), the quasi‐free electron bremsstrahlung (QFEB) and the atomic bremsstrahlung (AB). Each background mechanism exhibits a different relative contribution in the PIXE continuum according to the projectile energy, the x‐ray region and the atomic number of the target element. The anisotropy of the SEB and AB continuum, peaking at 90° with respect to the beam axis, has been confirmed and studied experimentally in the past. In the present work, the degree of polarization of the PIXE continuum was determined experimentally in the energy region 3–5 keV for a solid, thick carbon target and for 2.5 and 3 MeV proton energies. Copyright © 2005 John Wiley & Sons, Ltd.
Combined micro‐PIXE facility and monochromatic cathodoluminescence spectroscopy applied to colored minerals of natural stones: an example from amazonite
Authors: Vaggelli Gloria , Borghi Alessandro , Cossio Roberto , Fedi Mariaelena , Fiora Laura , Giuntini Lorenzo , Massi Mirko , Olmi Filippo 
Published: May 2005

AbstractQuantitative micro‐PIXE and cathodoluminescence spectra obtained for amazonite crystals from Malawi and Brazil granitoids, in order to check the trace elements presumably responsible for their color. These granitoids, used as Natural Stones for inside coverings and furnishings, are precious and rare, and owe their preciousness to the color of the rock‐forming aquamarine amazonite. The trace elements investigated by means of micro‐PIXE show the occurrence of Fe, Rb, Pb and Ga at concentrations above the minimum detection limit. In particular, the Malawi amazonite has a higher Pb content than the Brazil amazonite, but for Pb content both samples show a nearly flat pattern profile along the whole crystals. The cathodoluminescence spectra in both samples display three main peaks at 284, 558 and 680 nm which may be attributed to the presence of Pb2+, Mn2+ and Fe3+, respectively. As no Mn was detected by PIXE we suggest that its occurrence is below the PIXE detection limit. Micro‐PIXE analysis and cathodoluminescence spectra of most common and uncolored K‐feldspars do not reveal the presence of lead; therefore we support the hypothesis of Pb as the chromophore source. Copyright © 2005 John Wiley & Sons, Ltd.
Micro‐PIXE characterization of different skin models
Authors: Gontier E. , Barberet P. , Barbotteau Y. , Gáspár K. , Habchi C. , Hunyadi J. , Incerti S. , Kiss B. , Mavon A. , Moretto P. , Pouthier T. , Rosdy M. , Surlève‐Bazeille J. E. , Ynsa M. D. 
Published: May 2005

AbstractBecause of the large natural inter‐individual variability and of some difficulties in obtaining material from surgery or from healthy volunteers, the use of human native skin in experimentation comes up against fierce competition from experimental models, such as reconstituted epidermis or human skin grafted in animals. In this study, micro‐PIXE was used in association with other ion beam microanalysis techniques to characterize different epidermis models on a microscopic scale. The ionic species were found to be highly compartmentalized in the different strata of human skin with a distribution that can be explained in the frame of the homeostatic barrier function. Reconstituted epidermis obtained from airlifted culture, epidermis of mice foot sole and human forehead skin grafts transplanted into mice are the models investigated and compared with human native skin. Very similar inorganic ion patterns were observed in all epidermis, suggesting comparable permeability barrier mechanisms and validating their use as alternative approaches to native skin experimentation. In the near future, we plan to use some of these models in penetration studies and for investigating effects of exposure to different environmental stresses. Copyright © 2005 John Wiley & Sons, Ltd.
Rapid chemical state analysis in air by highly sensitive high‐resolution PIXE using a v. Hamos crystal spectrometer
Authors: Maeda Kuniko , Hasegawa Kenichi , Maeda Masaru , Ogiwara Kiyoshi , Hamanaka Hiromi 
Published: May 2005

AbstractA high‐resolution PIXE system composed of a curved crystal and a position‐sensitive proportional counter in v. Hamos geometry was constructed for rapid chemical state analysis in air. Data processing software to measure the time variation of PIXE spectra was installed in the system. The system was applied to obtain time‐resolved spectra of sulfur Kβ on the minute time‐scale. Time‐dependent variation of the fine structure was recognized clearly in the S Kβ spectra obtained from marine sediment samples. Copyright © 2005 John Wiley & Sons, Ltd.
Context induction: A proof principle for behavioural abstractions and algebraic implementations
Authors: Hennicker Rolf 
Published: May 2005

Abstract
An induction principle, called context induction, is presented which is appropriate for the verification of behavioural properties of abstract data types. The usefulness of the proof principle is documented by several applications: the verification of behavioural theorems over a behavioural specification, the verification of behavioural implementations and the verification of “forget-restrict-identify” implementations.
In particular, it is shown that behavioural implementations and “forget-restrict-identify” implementations (under certain assumptions) can be characterised by the same condition on contexts, i.e. (under the given assumptions) both concepts are equivalent. This leads to the suggestion to use context induction as a uniform proof method for correctness proofs of algebraic implementations.
Reconstruction of the thumb and digit by toe to hand transplantation
Authors: Chen Zhong Wei , Chen Zheng Rong 
Published: May 2005

AbstractSince the rapid development of microsurgery it is feasible to replant most severed thumbs and digits. In certain patients, however, the trauma is so severe that replantation cannot be performed, such as crush or burst injuries where the amputated part is badly smashed or broken into pieces. There are many methods used to reconstruct amputated thumbs or digits. In our hospital reconstruction of the thumb is accomplished by second toe transplantation, nail flap of the great toe transplantation and bone graft, and nail flap of the great toe and skeleton from the second toe transplantation. Reconstruction of fingers is undertaken through second toe transplantation and second and third toe transplantation. After total loss of the hand, double second toe transplant is used for reconstruction.
Emergency repair and reconstruction in the severely crushed hand
Authors: De S. Das , Tai Lee Soon , Pho Robert W. H. 
Published: May 2005

AbstractCrushing injuries of the hand are a common clinical problem which require judgement and assessment by an experienced hand surgeon for an optimum result. The crushed hand has to be viewed in the perspective of injury to an essential organ with its skin and contents, namely muscles, vessels, nerves, tendons, bone and joints. A poor result is often due to inadequate wound debridement, failure to identify the extent of crushing of the devitalized tissue, closure of the skin under tension in the presence of wound contamination, and complex repairs in an avascular bed. In an emergency situation, the simplest suitable procedure is preferred. Open degloving injuries, grease and paint gun injuries, and especially closed crushing, degloving injuries can be very misleading and need special attention.
Open approach in pancreatic and infected pancreatic necrosis: Laparostomies and preplanned revisions
Authors: Függer Reinhold , Schulz Franz , Rogy Michael , Herbst Friedrich , Mirza Darius , Fritsch Arnulf 
Published: May 2005

AbstractOne hundred and two patients with acute necrotizing pancreatitis were treated in accordance with a combined regimen of necrosectomy, open drainage by laparostomies, and repeated re‐explorations. The severity of pancreatitis was assessed by the APACHE II score (median 15 on admission). Eighty‐seven (85%) patients were classified as having infected pancreatic necrosis and only 15 (15%) as having pancreatic necrosis. Overall, 36 (35%) patients died, most of multiple organ failure. Survival was significantly impaired by bacterial contamination of pancreatic necrosis (p=0.008),bacteremia (p=0.0001)and infected bronchial secretions (p=0.05).The mortality rate was reduced from 53% to 28% by changing the regimen of re‐explorations from on demand to regular 48 hour intervals. Despite the fact that open packing was associated with a high frequency of gastrointestinal fistulas (30%), this concept seems to be a successful and recommendable approach in the therapy of pancreatic and infected pancreatic necrosis.
Hyperthermo‐chemotherapy combined with cytoreductive surgery for the treatment of gastric cancer with peritoneal dissemination
Authors: Yonemura Yutaka , Fujimura Takashi , Fushida Sachio , Takegawa Shigeru , Kamata Toru , Katayama Kanji , Kosaka Takeo , Yamaguchi Akio , Miwa Kouichi , Miyazaki Ituo 
Published: May 2005

AbstractContinuous hyperthermic peritoneal perfusion (CHPP) with anticancer agents (mitomycin C and cisplatin) in warm saline was performed in patients with peritoneal dissemination of gastric cancer following resection of the primary lesion. The effect of CHPP was examined by a second‐look operation. This study includes 41 cases of gastric cancer with peritoneal dissemination but without liver metastasis treated during the past 6 years. The overall median survival was 14.6 months to 64.2 months from CHPP to death and the 3‐year survival rate was 28.5%. Second look surgery revealed a remarkable diminution in the degree of peritoneal dissemination in 7 (50%) of 14 patients with disappearance of ascites after only one course of CHPP in 7 (77.8%) of 9 patients. Long‐term 3 year‐survival was noted in 4 (9.8%) patients on CHPP. Side effects were renal insufficiency in 2 (5%) patients, leukopenia in 2 (5%) patients, and perforation of the small intestine in 1 (2%) patient. These results suggest the effectiveness of CHPP in the treatment of gastric cancer with peritoneal dissemination.