bluuebunny/crossref_metadata_2025_split huggingface dataset:
Cumulative effect of disinfection procedures on microhardness and tridimensional stability of a poly(methyl methacrylate) denture base resin
Authors: Sartori Evandro Afonso , Schmidt Caroline Bom , Mota Eduardo Gonçalves , Hirakata Luciana Mayumi , Shinkai Rosemary Sadami Arai 
Published: December 2007

AbstractMicrowave irradiation has been used for disinfection of dentures instead of chemical solutions; yet, its effect on resin properties after repeated procedures still is unclear. This study evaluated the cumulative effect of two disinfection methods on Knoop microhardness and tridimensional stability of a poly(methyl methacrylate) denture base resin. For the microhardness measurement, 24‐resin discs received mechanical polishing and were submitted to the following treatments: (1) control (no disinfection), (2) chemical disinfection (immersion in 100ppm chloride solution for 24h), or (3) microwave disinfection (irradiation at 690 W for 6 min). Disinfection procedures were performed twice (T1, T2) with a 7‐day interval. Knoop microhardness was recorded after polishing (T0) and after T1 and T2. For the dimensional stability test (measured by the adaptation of the denture bases), 36‐maxillary denture bases were obtained from type III dental stone casts duplicated from a metallic master model and submitted to the disinfection treatment. Adaptation of denture bases was measured at baseline (T0) and after T1 and T2 by weighing a vinyl polysiloxane film reproducing the gap between resin base and master model. Data were analyzed by ANOVA GLM for repeated measures and Bonferroni's test, α = 0.05. Knoop microhardness was not modified by any disinfection procedure but decreased over time. Denture resin bases submitted to microwave disinfection had gradual increase of distortion over time, while bases immersed in chloride solution did not differ from the control group and remained dimensionally stable from T1 to T2. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2008
Assessment of tissue repair in full thickness chondral defects in the rabbit using magnetic resonance imaging transverse relaxation measurements
Authors: Ramaswamy Sharan , Gurkan Ilksen , Sharma Blanka , Cascio Brett , Fishbein Kenneth W. , Spencer Richard G. 
Published: December 2007

AbstractThe purpose of this study was to determine if the noninvasive and nondestructive technique of magnetic resonance imaging could be used to quantify the amount of repair tissue that fills surgically‐induced chondral defects in the rabbit. Sixteen 4‐mm diameter full‐thickness chondral defects were created. A photopolymerizable hydrogel was used to seal the defects as a treatment modality. At 5 weeks, the animals were sacrificed and the distal femur was subjected to MRI analyses at high field (9.4 T). The transverse relaxation time (T2) in each defect was measured. Histology and histomorphometric analysis were used to quantify the amount of repair tissue that filled each defect. The relationship between T2 and percent tissue fill was found to fit well to a negatively sloped, linear model. The linear (Pearson's product‐moment) correlation coefficient was found to be r = −0.82 and the associated coefficient of determination was r2 = 0.67. This correlation suggests that the MRI parameter T2 can be used to track changes in the amount of repair tissue that fills cartilage defects. This would be especially useful in in vivo cartilage tissue engineering studies that attempt to determine optimal biomaterials for scaffold design. Published 2007 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2008
Hybrid coating of hydroxyapatite and collagen within poly(D,L‐lactic‐co‐glycolic acid) scaffold
Authors: Li Jiashen , Yuan Xiaoyan , He Fei , Mak Arthur F. T. 
Published: December 2007

AbstractTo improve the cell‐affinity of biodegradable polymer scaffold, coating hydroxyapatite (HA) or collagen on the surface of polymer materials seemed to be a strategy to combine both advantages of them. The objective of this study was to develop a novel method to introduce HA and collagen inside polymer scaffold uniformly. HA and collagen suspension was mixed with paraffin microspheres, and molded to form a composite sample. After the sample was dried, HA/collagen composite was left among and on the surface of paraffin microspheres. Poly(D,L‐lactic‐co‐glycolic acid) (PLGA) (50/50) solution was cast into the inter‐space of the paraffin microspheres and dried. Afterwards, the paraffin was dissolved and removed, HA/collagen was transferred to the surface and even inside of the pore wall of PLGA scaffolds. Collagen fibers and HA particles which were inlaid inside the PLGA pore wall could help to enhance the coating strength between HA/Col coating and the pore wall surface of the PLGA scaffold. The scaffolds with HA/Col coating were expected to exhibit desirable properties in bone tissue engineering. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2008
Metal ion release from fracture fixation devices: A potential marker of implant failure
Authors: Savarino L. , Maci G. S. , Greco M. , Baldini N. , Giunti A. 
Published: December 2007

AbstractStainless steel is the alloy most frequently used for fracture fixation devices (FFD). We aimed to verify if the ion release evaluation could be a surrogate marker of performance and could allow an early detection of implant failure in patients with stainless steel FFD. We measured the nickel (Ni) and chromium (Cr) serum content in patients undergoing the retrieval of stainless steel plates (group I) or intramedullary nails (group II), because of consolidation or failure. Forty‐five healthy donors were recruited as controls. Furthermore, the diagnostic performance of these values was evaluated: analysis power, sensitivity, specificity, positive and negative predictive values, likelihood ratios, and diagnostic accuracy were calculated. A significant increase of ion values was demonstrated in patients with failed plates, compared with the values recorded in patients with well‐fixed plates (p = 0.002 for Cr and p = 0.002 for Ni), and in healthy subjects (p = 0.0002 for Cr and p = 0.003 for Ni). No significant difference was found between stable implants and controls (p = 0.8 for Cr and p = 0.06 for Ni). A high specificity (0.92 for Cr and 1.00 for Ni), positive predictive value (0.87 for Cr and 1.00 for Ni), and positive likelihood ratio (9.10 for Cr) were calculated for ion testing in plates. The substantial metal content elevations in patients with plates and the positive likelihood ratio above 5 for chromium testing suggest that ion dosage may be a useful surrogate marker for the presence of malfunctioning of these devices, perhaps before the onset of clinical and radiographic changes. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2008
The effect of surface treatments on the fretting behavior of Ti‐6Al‐4V alloy
Authors: Dalmiglio Matteo , Schaaff Petra , Holzwarth Uwe , Chiesa Roberto , Rondelli Gianni 
Published: December 2007

AbstractStem modularity in total hip replacement introduces an additional taper joint between Ti‐6Al‐4V stem components with the potential for fretting corrosion processes. One possible way to reduce the susceptibility of the Ti‐6Al‐4V/Ti‐6Al‐4V interface to fretting is the surface modification of the Ti‐6Al‐4V alloy. Among the tested, industrially available surface treatments, a combination of two deep anodic spark deposition treatments followed by barrel polishing resulted in a four times lower material release with respect to untreated, machined fretting pad surfaces. The fretting release has been quantified by means of radiotracers introduced in the alloy surface by proton irradiation. In a simple sphere on flat geometry, the semispherical fretting pads were pressed against flat, dog‐bone shaped Ti‐6Al‐4V fatigue samples cyclically loaded at 4 Hz. In this way a cyclic displacement amplitude along the surfaces of 20 μm has been achieved. A further simplification consisted in the use of deionized water as lubricant. A comparison of the radiotracer results with an electrochemical material characterization after selected treatments by potentiostatic tests of modular stems in 0.9% NaCl at 40°C for 10 days confirmed the benefit of deep anodic spark deposition and subsequent barrel polishing for improving the fretting behavior of Ti‐6Al‐4V. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2008
Globally convergent computation of chemical equilibrium composition
Authors: Patil Sunil , Aiyer R. C. , Sharma K. C. 
Published: December 2007

AbstractWe report the Newton–Raphson based globally convergent computational method for determination of chemical equilibrium composition. In the computation of chemical equilibrium composition, an appearance of nonpositive value of number of moles of any component leads to discrepancy. The process of conditional backtracking and adaptive set of refining factors for Newton–Raphson steps are employed to resolve the problem. The mathematical formulation proposed by Heuze et al. (J Chem Phys 1985, 83, 4734) has been solved using proposed computational method, instead of empirical iterative formulation, as proposed by them. Results for the same numerical example, used by Heuze et al. (J Chem Phys 1985, 83, 4734) and White et al. (J Chem Phys 1958, 28, 751) are presented in addition to decomposition of Cyclotrimethylenetrinitramine for fixed temperature and pressure. It is observed that the proposed method is efficient and globally convergent. An even noteworthy finding is that the set of refining factors can be chosen from the range 0.1 to η, where η may be greater than one depending on how smoothly system of nonlinear equations is dependant on corresponding variable. Related analysis and results are discussed. © 2007 Wiley Periodicals, Inc. J Comput Chem, 2008
A dual‐level state‐specific time‐dependent density‐functional theory
Authors: Tokura Seiken , Sato Takeshi , Tsuneda Takao , Nakajima Takahito , Hirao Kimihiko 
Published: December 2007

AbstractA highly efficient new algorithm for time‐dependent density‐functional theory (TDDFT) calculations is presented. In this algorithm, a dual‐level approach to speed up DFT calculations (Nakajima and Hirao, J Chem Phys 2006, 124, 184108) is combined with a state‐specific (SS) algorithm for TDDFT (Chiba et al., Chem Phys Lett 2006, 420, 391). The dual‐level SS‐TDDFT algorithm was applied to excitation energy calculations of typical small molecules, the Q bands of the chlorophyll A molecule, the charge‐transfer energy of the zincbacteriochlorin–bacteriochlorin model system, and the lowest‐lying excitation of the circumcoronene molecule. As a result, it was found that the dual‐level SS‐TDDFT gave correct excitation energies with errors of 0.2–0.3 eV from the standard TDDFT approach, with much lower CPU times for various types of excitation energies of large‐scale molecules. © 2007 Wiley Periodicals, Inc. J Comput Chem, 2008
Molecular dynamics of a calix[4]arene‐containing polymer in dichloromethane solution: Ability of the solvent molecules to fill the cavity of the macrocycle
Authors: Rodríguez‐Ropero Francisco , Zanuy David , Alemán Carlos 
Published: December 2007

AbstractThe structure and dynamics of the dichloromethane solvent around the calix[4]arene units contained in the molecular actuator poly(calix[4]arene bis‐bithiophene) have been examined using a 1‐μs molecular dynamics simulation. Results indicate that a solvent molecule fills the cavity associated to the cone conformation of the macrocycle during a significant period of time, especially when the actuator is not contracted. The position of such solvent molecule presents a fourfold symmetry with a maximum orientation toward the center of each ring contained in the calix[4]arene. Frequently, the solvent molecule located inside the cavity is rapidly exchanged for another molecule of the bulk. Thus, the number of dichloromethane molecules that reside more than 0.5 ns inside the cavity is relatively small. Finally, we detected that a significant number of solvent molecules are able to migrate from the cavity of one calix[4]arene to the cavity/ies of other/s, suggesting that the dynamics of the bulk solvent is important for the formation of these inclusion complexes. © 2007 Wiley Periodicals, Inc.J Comput Chem, 2008
Assessment of performance of the general purpose polarizable force field QMPFF3 in condensed phase
Authors: Donchev Alexander G. , Galkin Nikolay G. , Illarionov Alexey A. , Khoruzhii Oleg V. , Olevanov Michael A. , Ozrin Vladimir D. , Pereyaslavets Leonid B. , Tarasov Vladimir I. 
Published: December 2007

AbstractThe recently introduced force field (FF) QMPFF3 is thoroughly validated in gas, liquid, and solid phases. For the first time, it is demonstrated that a physically well‐grounded general purpose FF fitted exclusively to a comprehensive set of high level vacuum quantum mechanical data applied as it is to simulation of condensed phase provides high transferability for a wide range of chemical compounds. QMPFF3 demonstrates accuracy comparable with that of the FFs explicitly fitted to condensed phase data, but due to high transferability it is expected to be successful in simulating large molecular complexes. © 2007 Wiley Periodicals, Inc. J Comput Chem, 2008
Fundamental vibrational frequencies and dominant resonances in methylamine isotopologues by ab initio and density functional theory methods
Authors: Levi Chen , Martin Jan M. L. , Bar Ilana 
Published: December 2007

AbstractAb initio and density functional theory (DFT) calculations were performed for obtaining fundamental vibrational frequencies of methylamine, CH3NH2, and its deuterated variants CH3ND2, CD3NH2, and CD3ND2. The calculations were carried out using the CCSD(T) coupled cluster approximation with cc‐pVTZ and cc‐pVQZ basis sets, and by the DFT method with the semiempirical hybrid functional B97‐1 with polarization consistent pc‐2 and pc‐3 basis sets. Reasonable performance of the DFT harmonic and ab initio harmonic calculations was found, which improved considerably upon combination of the harmonic fundamental frequencies with anharmonic corrections from the smaller, pc‐2, basis. The computed anharmonic fundamental frequencies of methylamine isotopologues agree very well with the experimental values and represent a useful tool for assignment and analysis of the dominant resonances. © 2007 Wiley Periodicals, Inc. J Comput Chem, 2008
Structure and singly occupied molecular orbital analysis of anionic tautomers of guanine
Authors: Haranczyk Maciej , Holliday John , Willett Peter , Gutowski Maciej 
Published: December 2007

AbstractRecently, we reported the discovery of adiabatically bound anions of guanine that might be involved in the processes of DNA damage by low‐energy electrons and in charge transfer through DNA. These anions correspond to some tautomers that have been ignored thus far. They were identified using a hybrid quantum mechanical–combinatorial approach in which an energy‐based screening was performed on the library of 499 tautomers with their relative energies calculated with quantum chemistry methods. In the current study, we analyze the adiabatically bound anions of guanine in two aspects: (1) the geometries and excess electron distributions are analyzed and compared with anions of the most stable neutrals to identify the sources of stability; (2) the chemical space of guanine tautomers is explored to verify if these new tautomers are contained in a particular subspace of the tautomeric space. The first task involves the development of novel approaches—the quantum chemical data like electron density, orbital, and information on its bonding/antibonding character are coded into holograms and analyzed using chemoinformatics techniques. The second task is completed using substructure analysis and clustering techniques performed on molecules represented by 2D fingerprints. The major conclusion is that the high stability of adiabatically bound anions originates from the bonding character of the π orbital occupied by the excess electron. This compensates for the antibonding character that usually causes significant buckling of the ring. Also, the excess electron is more homogenously distributed over both rings than in the case of anions of the most stable neutral species. In terms of 2D substructure, the most stable anionic tautomers generally have additional hydrogen atoms at C8 and/or C2 and they do not have hydrogen atoms attached to C4, C5, and C6. They also form an “island of stability” in the tautomeric space of guanine. © 2007 Wiley Periodicals, Inc. J Comput Chem, 2008
Functional display of Rhizomucor miehei lipase on surface of Saccharomyces cerevisiae with higher activity and its practical properties
Authors: Zhang Wei‐Guo , Han Shuang‐Yan , Wei Dong‐Zhi , Lin Ying , Wang Xiao‐Ning 
Published: December 2007

AbstractBACKGROUND: A display system, which can translate DNA to functional peptides or proteins, is used as a new protein expression system. In this system, peptides or proteins are displayed on the cell surface as a fusion form with some anchoring proteins. Yeast cells displaying lipases on their cell‐surface could be used as whole‐cell biocatalysts. This research focuses on the functional display of Rhizomucor miehei lipase (RML) on the surface of Saccharomyces cerevisiae with higher activity.RESULTS: The lipases (RML) from R.miehei 3.4960 were of active form. The RML‐α‐agglutinin fusion proteins produced were not secreted into the culture media and were mostly immobilized on the yeast cells. Cell surface displayed lipase showed the highest activity at 45 °C and pH 8.0.CONCLUSION: The gene encoding RML from R.miehei 3.4960 can be functionally expressed on the cell surface of S. cerevisiae MT8‐1 using a glycosylphosphatidylinositol (GPI) anchor with higher activity. Copyright © 2007 Society of Chemical Industry
Myosin regulatory light chain expression in trout muscle
Authors: Donato Megan E. , Schiavi Jonathan , Ulerich Alexis D. , Weaver Frances E. , Coughlin David J. 
Published: December 2007

AbstractMuscle's contractile properties can vary along different trajectories, including between muscle fiber types, along the body (within a muscle fiber type), and between developmental stages. This study explores the role of the regulatory myosin light chain (MLC2) in modulating contractile properties in rainbow trout myotomal muscle. Rainbow trout show longitudinal variations in muscle activation and relaxation, with faster contractile properties in the anterior myotome. The expression of two muscle proteins, troponin T and parvalbumin, vary along the length of trout in concert with shifts in muscle activation and relaxation. However, there is no longitudinal variation in myosin heavy chain in trout. This study explores the role of MLC2 (or regulatory light chain), part of the myosin hexamer, in contributing to longitudinal variations in contractile properties of trout swimming muscle. We cloned and sequenced two isoforms of MLC2 from trout muscle and used real‐time quantitative polymerase chain reaction to assess the relative expression of these two isoforms in red and white muscle from different body positions of two ages of rainbow trout: parr and smolt. Longitudinal variations in slow (sMLC2) but not fast (fMLC2) regulatory light chain isoforms were observed in young trout parr but not older trout smolts. The differences in sMLC2 expression correlated with shifts in muscle contractile properties in the parr. J. Exp. Zool. 309A:64–72, 2008. © 2007 Wiley‐Liss, Inc.
PCR survey of Xenoturbella bocki Hox genes
Authors: Fritzsch Guido , Böhme Manja U. , Thorndyke Mike , Nakano Hiroaki , Israelsson Olle , Stach Thomas , Schlegel Martin , Hankeln Thomas , Stadler Peter F. 
Published: December 2007

AbstractXenoturbella bocki has recently been identified as one of the most basal deuterostomes, although an even more basal phylogenetic position cannot be ruled out. Here we report on a polymerase chain reaction survey of partial Hox homeobox sequences of X. bocki. Surprisingly, we did not find evidence for more than five Hox genes, one clear labial/PG1 ortholog, one posterior gene most similar to the PG9/10 genes of Ambulacraria, and three central group genes whose precise assignment to a specific paralog group remains open. We furthermore report on a re‐evaluation of the available published evidence of Hox genes in other basal deuterostomes. J. Exp. Zool. (Mol. Dev. Evol.) 310B:278–284, 2008. © 2007 Wiley‐Liss, Inc.
Angiopoietin‐1 and ‐2 expression in recurrent squamous cell carcinoma of the oral cavity
Authors: Chien Chih‐Yen , Su Chih‐Ying , Chuang Hui‐Ching , Fang Fu‐Min , Huang Hsuan‐Ying , Chen Ching‐Mei , Chen Chang‐Han , Huang Chao‐Cheng 
Published: December 2007

AbstractBackground and ObjectivesOur objective was to evaluate the clinical significance of angiopoietin‐1 (Ang‐1) and Ang‐2 expression in recurrent but operable squamous cell carcinoma of the oral cavity (OCSCC).Patients and MethodsFormalin‐fixed, paraffin‐embedded tissues from 40 patients who underwent surgical intervention for local or local‐regional recurrent OCSCC between 1995 and 2005 were immunohistochemically analyzed for Ang‐1 and Ang‐2 expression.ResultsThe recurrent TNM staging classified 5 patients as stage I, 4 as stage II, 2 as stage III, and 29 as stage IV. The actuarial 3‐year disease‐free survival rate was 43.1% with a mean follow‐up of 18.4 months (ranged 1–70 months). High expression of Ang‐1 was significantly correlated with positive nodal stage (P = 0.041). Patients with more advanced recurrent stage of the tumors (P = 0.0036) and high expression of Ang‐2 (P = 0.045) showed lower actuarial 3‐year disease‐free survival. However, Cox's regression analysis revealed that only recurrent tumor (rT) stage was an independent prognostic factor for survival (P = 0.019, 95% CI = 1.473–82.017, relative risk = 10.992).ConclusionsRecurrent OCSCC with high Ang‐1 or Ang‐2 expression in the tumor bed exhibits aggressive tumor behavior. However, the salvage outcome depends on the rT stage. J. Surg. Oncol. 2008;97:273–277. © 2007 Wiley‐Liss, Inc.
Concurrent administration of zoledronic acid and irradiation leads to improved bone density, biomechanical strength, and microarchitecture in a mouse model of tumor‐induced osteolysis
Authors: Arrington Sarah A. , Damron Timothy A. , Mann Kenneth A. , Allen Matthew J. 
Published: December 2007

AbstractBackground and ObjectivesBone metastases are typically treated with bisphosphonates as adjuncts to radiation therapy. The goal of this study was to determine whether radiotherapy combined with a bisphosphonate could restore bone density, microarchitecture, and biomechanical strength of a tumor‐burdened bone to normal.Materials and MethodsBreast cancer cells were injected into the right femur of 30 female nude mice. Mice were divided into three treatment groups (0 Gy, 20 Gy, and 20 Gy + ZA). Left limbs served as non‐operated normal bones. Tumor‐bearing femora were irradiated 3 weeks later. ZA (100 µg/kg SC) was administered once weekly for 6 weeks. Mice were euthanized at 9 weeks or earlier if severe lameness or pathology occurred.ResultsMice treated with 20 Gy/ZA exhibited higher bone density, bone volume, fractional trabecular bone volume, and biomechanical strength compared to mice treated with 20 Gy only (P < 0.05). Statistical analysis revealed that mice treated with 20 Gy/ZA were not significantly different from normal bones with respect to bone density and strength. Micro‐CT reconstructions showed improved microarchitecture in the 20 Gy/ZA group compared to 20 Gy.ConclusionsTreatment of an osteolytic bone with radiation therapy plus zoledronic acid restores normal bone qualities with respect to bone density, microarchitecture, and biomechanical strength. J. Surg. Oncol. 2008;97:284–290. © 2007 Wiley‐Liss, Inc.