bluuebunny/crossref_metadata_2025_split huggingface dataset:
Fetal operations in the head and neck area: current state
Authors: Wagner Wolfgang , Harrison Michael R. 
Published: October 2004

AbstractBackgroundFetal surgery is defined as prenatal surgical intervention. Such intervention is currently considered in selected cases of fetal malformations that endanger the child’s life prenatally or postnatally, such as death or severe impairment.MethodsCurrent indications are reviewed, with special emphasis on success rates and complications, including concomitant ethical problems. Data sources are based on personal experience and medical information systems (especially MEDLINE).Results and ConclusionsIn the head and neck areas, especially the upper respiratory tract, such procedures can be indicated in selected cases. They include exposure and temporary obstruction of the fetal trachea to reduce the viscera and to prevent pulmonary hypoplasia in congenital diaphragmatic hernia, prenatal tracheotomy in laryngeal atresia, and intranatal establishment of an airway in airway‐obstructing embryonic tumors. The latter surgery can be performed after delivery of the fetal head and neck and before umbilical cord severance. This method ensures oxygenation of the fetus by the maternofetal circulation until completion of the surgical intervention (so called EXIT procedure = Ex‐Utero Intrapartum Treatment). The relatively high surgical risk of fetal surgery, in particular postoperative preterm labor, may be reduced by the use of minimally invasive endoscopic techniques. By reducing operative risks even further, prenatal surgical interventions may even be used in nonlethal conditions. Consequently, more diseases of the head and neck area could thus be included in the spectrum of indications, such as prenatal correction of the cleft lip palate. Because fetal wound healing incurs no scarring up to a certain stage in pregnancy, such fetal surgical correction could be a perspective. © 2002 Wiley Periodicals, Inc. Head Neck 24: 482–490, 2002
Performance obstacles in cellular manufacturing implementation— empirical investigation
Authors: Park K. S. , Han S. W. 
Published: October 2004

AbstractPerformance obstacles are factors in the work environment that restrict productivity by inhibiting workers in the execution of task responsibilities. It is thus crucial to identify and reduce those obstacles for more effective cellular manufacturing implementation. This article describes research carried out in 4 Korean manufacturing plants to investigate performance obstacles in cellular manufacturing implementation. The results of the research reveal several important factors in cellular manufacturing implementation: training and education, information, teamwork skill, supervision, and scheduling. This research discusses human and organizational factors in new manufacturing system implementation and reveals that those factors play a central role in the implementation. © 2002 John Wiley & Sons, Inc.
Dentin proteoglycans: An immunocytochemical FEISEM study
Authors: Breschi L. , Lopes M. , Gobbi P. , Mazzotti G. , Falconi M. , Perdigão J. 
Published: October 2004

AbstractDentin proteoglycans are fundamental constituents of the dentin matrix and are distributed ubiquitously both in dentin and cement. They have several important functional properties; in particular, they have a fundamental role in the maintenance and the correct stabilization of collagen fibers. The use of phosphoric acid on dentin, as proposed in most common dental adhesive systems to establish a reliable bond, may affect the molecular structure of proteoglycans. The aim of this study was to evaluate, after the application of EDTA or phosphoric acid on dentin, the dentin proteoglycans with an immunocytochemical approach with high resolution SEM. For this purpose, dentin disks obtained from recently extracted human molars were etched with a 35% water solution of phosphoric acid for 15 s, 30 s, and 60 s. Control specimens were conditioned with EDTA. Specimens were immunolabeled with a monoclonal antibody antichondroitin sulfate and visualized with a gold‐conjugated secondary antibody. Conditioning dentin with EDTA resulted in a distinct labeling of the proteoglycans, as visualized on branching fibrillar structures in the order of 10–20 nm. The use of 35% phosphoric acid on dentin revealed a coagulation of proteoglycans after etching for 15 s while a very low labeling signal was detectable after 30 s. No labeling was obtained after etching dentin with phosphoric acid for 60 s. These results suggest that the use of 35% phosphoric acid on dentin is able to produce significant structural modifications of the dentin proteoglycans even after short application times. Additionally, when applied on the dentin surface for more than 30 s, phosphoric acid produces a dramatic decrease in proteoglycans’ antigenicity, probably due to structural modifications of the three‐dimensional conformation of these molecules. © 2002 Wiley Periodicals, Inc. J Biomed Mater Res 61: 40–46, 2002.
Self‐curing acrylic formulations containing PMMA/PCL composites: Properties and antibiotic release behavior
Authors: Méndez José A. , Abraham Gustavo A. , Fernández María del Mar , Vázquez Blanca , Román Julio San 
Published: October 2004

AbstractPartially biodegradable acrylic composites containing poly(methyl methacrylate)–poly(ϵ‐caprolactone) (PMMA/PCL) systems were prepared by mixing the corresponding PMMA/PCL beads (89:11, 86:14, 83:17, and 77:23 weight ratio) used as solid phase with methyl methacrylate (MMA) (liquid phase) in a solid/liquid ratio of 1.5:1. The physical and chemical microheterogeneity of these beads influenced significantly the curing parameters, because several aspects involved in the polymerization reaction are closely related to both morphology and size distribution of the particles. In vitro behavior was studied by immersion in simulated body fluid at pH = 7.4 and 37°C for more than 8 weeks and the composition was followed by 1H‐nuclear magnetic resonance spectroscopy. Approximately 2% wt/wt weight loss was observed after a period of 8 weeks for the composites richest in PCL. Mechanical properties of the dry and wet specimens were evaluated by compressive and tensile tests. In all cases, the presence of PCL in the composites provided a significant decrease in both compressive strength and elastic modulus compared with plain PMMA. Tensile and compressive strength also decreased significantly after 2 weeks of immersion in simulated body fluid compared with dry specimens. The self‐curing composites based on PMMA/PCL beads and loaded with 3% wt/wt vancomycin were evaluated as carriers for local release of antibiotics. The composite prepared with beads of PMMA/PCL ratio 86:14 was the most effective. It eluted 64% of the initial drug within the first 5 h, allowing progressive release of nearly the total amount of the initial drug (90%) in approximately 2 months. The results obtained suggest that the described composites can be suitable for antibiotic release in non‐load bearing graft applications. © 2002 Wiley Periodicals, Inc. J Biomed Mater Res 61: 66–74, 2002
Chondroinduction of mouse mesenchymal stem cells in three‐dimensional highly porous matrix scaffolds
Authors: Aung Tun , Miyoshi Hirotoshi , Tun Thein , Ohshima Norio 
Published: October 2004

AbstractPorous polyvinyl formal (PVF) resin and poly(lactide‐caprolactone) [P(LA/CL)] sponges were examined as three‐dimensional matrices for chondroinduction of cultured bone marrow mesenchymal stem cells (MSCs). Approximately 5 × 105 mouse MSCs were seeded in porous PVF resin or P(LA/CL) sponges and were cultured for up to 1 month in serum‐free high‐glucose Dulbecco's modified Eagle's medium containing 10 ng/mL transforming growth factor‐β3 and 100 nM dexamethasone for chondroinduction. After the 1‐month culture period, the PVF resin and P(LA/CL) sponges contained approximately twice the amount of glycosaminoglycans compared with the control pellet. Safranin‐O staining of PVF and P(LA/CL) after 1 month of culture revealed a cartilage‐like extracellular matrix containing glycosaminoglycans and collagen. When implanted into nude mice, PVF and P(LA/CL) seeded with MSCs were found to be both biocompatible and chondroinductive. These highly porous scaffolds can maintain a large number of cells in a three‐dimensional structure. Both are potentially promising for the chondroinduction of bone marrow MSCs for research and clinical applications. © 2002 Wiley Periodicals, Inc. J Biomed Mater Res 61: 75–82, 2002
Cytotoxicity of glutaraldehyde crosslinked collagen/poly(vinyl alcohol) films is by the mechanism of apoptosis
Authors: Gough Julie E. , Scotchford Colin A. , Downes Sandra 
Published: October 2004

AbstractCollagen has been investigated as a potential natural biomaterial, because of its occurrence in the extracellular matrix. Collagen requires crosslinking in this context, by reagents that are often cytotoxic. Glutaraldehyde is one such agent that is potentially cytotoxic. The aim of this study was to determine the cause of poor cell attachment and growth on collagen/poly(vinyl alcohol) bioartificial composite films, when crosslinked with glutaraldehyde. Dehydrothermal crosslinking was used as a comparison. Human osteoblasts were observed to undergo apoptosis on glutaraldehyde crosslinked films dependent on concentration of collagen present. Higher collagen content resulted in higher levels of apoptosis with poor cell attachment and spreading of remaining cells. Post‐treatment of films with 8% L‐glutamic acid prevented the apoptotic response of osteoblasts and allowed attachment and spreading. The addition of 100 nM insulin‐like growth factor‐1 to the culture medium also prevented apoptosis. Glutaraldehyde toxicity of crosslinked collagen has been demonstrated in this study, the mechanism of which is apoptosis. This study indicates that poor biocompatibility and induction of apoptosis on collagen/poly(vinyl alcohol) films crosslinked by glutaraldehyde are attributed to glutaraldehyde components on the surface of the films (not residual glutaraldehyde), whose effects can be quenched by glutamic acid, and prevented by insulin‐like growth factor‐1. © 2002 Wiley Periodicals, Inc. J Biomed Mater Res 61: 121–130, 2002
Synthesis of pH‐sensitive inulin hydrogels and characterization of their swelling properties
Authors: Chiu Hsin‐Cheng , Hsu Yuan‐Hung , Lin Pei‐Jung 
Published: October 2004

AbstractIn this study, pH‐responsive inulin hydrogels were prepared by radical copolymerization of methacrylated inulin (MA‐inulin) with acrylic acid (AAc) in aqueous solution using ammonium peroxydisulfate (APS) and N,N,N′,N′‐tetramethylethylenediamine (TMEDA) as an initiation system. The AAc content in hydrogels was evaluated by FTIR spectroscopy. The covalent bridging of AAc among MA moieties of MA‐inulins was observed by a significant increase in the effective network density of hydrogels and further confirmed by TGA studies. While, at a low content of AAc, the hydration of hydrogels at pH 7.4 decreased owing to the increased crosslinking density, the swelling subsequently increased with further increasing AAc as a consequence of the increased ionic osmotic pressure within hydrogels. The change in swelling of hydrogels in response to pH change between 7.4 and 2.2 was therefore enlarged when the AAc content increased. © 2002 Wiley Periodicals, Inc. J Biomed Mater Res 61:146–152, 2002
In vitro mineralization of a glass‐ceramic of the MgO‐3CaO · P2O5‐SiO2 system: Wettability studies
Authors: Serro A. P. , Fernandes A. C. , Saramago B. , Fernandes M. H. V. 
Published: October 2004

AbstractThe calcium phosphate deposition on the surface of a bioactive glass‐ceramic of the MgO‐3CaO · P2O5‐SiO2 system during a 1‐week immersion in biological model fluids, was investigated through wettability studies. Two model fluids with chemical composition similar to the human blood plasma were tested: Hanks’ balanced salt solution (HBSS) and a simulated body fluid (SBF) with a higher calcium content. The effect of the presence of albumin, both in solution or previously adsorbed to the surface, was assessed. The behavior observed using two SBF solutions prepared with and without TRIS buffer was compared. The surface free energy of the glass‐ceramic samples was determined, before and after immersion, and dynamic contact angle analysis was performed using the biological model fluids as scanning liquids. Scanning electron microscope observations and x‐ray photoelectron spectroscopy (XPS) analysis were performed to complement the wettability studies. The experimental results led to the conclusion that the precipitation of a calcium phosphate film in HBSS occurred mainly when the immersion solution was renewed daily or in the presence of adsorbed albumin. In SBF, the addition of TRIS buffer seemed to inhibit the formation of the calcium phosphate film. © 2002 Wiley Periodicals, Inc. J Biomed Mater Res 61: 99–108, 2002
Selective induction of mitogen‐activated protein kinases in human lens epithelial cells by ultraviolet radiation
Authors: Bomser Joshua A. 
Published: October 2004

AbstractThe present study investigates the effects of ultraviolet radiation (UVR) on mitogen‐activated protein kinase (MAPK) activity in human lens epithelial (HLE) cells. Irradiation of HLE cells with ultraviolet B and ultraviolet C radiation activates the stress‐response MAPK proteins, p38 and c‐Jun NH2‐terminal kinase (JNK), in a dose‐ and time‐dependent manner, while the extracellular‐regulated signal kinase (ERK 44/42) cascade was not altered by UVR exposure. Ultraviolet A radiation failed to elicit a MAPK response. UVR‐induced MAPK activation does not require protein kinase C or phosphatidylinositol 3‐kinase activity, suggesting that this is not a receptor‐mediated event. Inhibition of ribosomal translation completely abolished UVR‐induced MAPK activation, while treatment with the antioxidant, N‐acetyl cysteine, and mild heat shock had no effect on this activation. These data demonstrate for the first time the selective activation of MAPK cascades in a lens epithelial cell line. © 2002 Wiley Periodicals, Inc. J Biochem Mol Toxicol 16:33–40, 2002; DOI 10.1002/jbt.10016
A smooth permittivity function for Poisson–Boltzmann solvation methods
Authors: Grant J. Andrew , Pickup Barry T. , Nicholls Anthony 
Published: October 2004

AbstractThis work introduces a continuous smooth permittivity function into Poisson–Boltzmann techniques for continuum approaches to modeling the solvation of small molecules and proteins. The permittivity function is derived using a Gaussian method to describe volume exclusion. The new method allows a rigorous determination of solvent forces within a grid‐based technology. The generality of approach is demonstrated by considering a range of applications for small molecules and macromolecules. We also present a very complete statistical analysis of grid errors, and show that the accuracy of our Gaussian‐based method is improved over standard techniques. The method has been implemented in a new code called ZAP, which is freely available to academic institutions.1 © 2001 John Wiley & Sons, Inc. J Comput Chem 22: 608–640, 2001
Ab initioquantum chemistry and molecular dynamics simulations studies of LiPF6/poly(ethylene oxide) interactions
Authors: Borodin Oleg , Smith Grant D. , Jaffe Richard L. 
Published: October 2004

AbstractAb initioand molecular mechanics studies of LiPF6and the interaction of the salt with the poly(ethylene oxide) (PEO) oligomer dimethylether have been performed. Optimized geometries and energies of Li+/PF6−complexes obtained from quantum chemistry revealed a preference for C3Vsymmetry structures for Li+–P separations under 2.8 Å, C2Vsymmetry for Li+–P in the range of 2.8–3.3 Å and C4Vsymmetry for Li+–P separations larger than 3.3 Å. Electron correlation effects were found to make an insignificant contribution to binding in the Li+/PF6−complex. By contrast, analogous studies of PF6−/PF6−and PF6−/dimethyl ether complexes revealed important contributions of electron correlation to the complex interaction energy. A molecular mechanics force field for simulations of PEO/LiPF6melts was parameterized to reproduce the geometries and energies of Li+/PF6−, PF6−/PF6−, PF6−/dimethylether complexes. Molecular dynamics simulations of PEO/LiPF6melts were performed to validate this quantum chemistry‐based force field. Accurate reproduction of the increase in solution density with addition of salt was found while the electrical conductivity of PEO/LiPF6solutions was found to be within an order of magnitude of the experimental values. © 2001 John Wiley & Sons, Inc. J Comput Chem 22: 641–654, 2001
Multiscale fast summation of long‐range charge and dipolar interactions
Authors: Sandak Bilha 
Published: October 2004

AbstractHere we present a linear order multiscale method for the fast summation of long range forces in a system consisting of a large number of charge and dipolar particles. For a N‐body system, our algorithm requires an order of work that is proportional to O(N), in comparison to order O(N2) of the direct pairwise computation. Our method is demonstrated on two‐dimensional homogeneous point‐charge and dipolar systems, and a combined heterogeneous particle system, for the calculation of the induced electrostatic potential and energy. The electrostatic interaction is decomposed into a local part and a smooth part. The method thus, has several potential advantages over other O(N log N) or O(N) techniques, especially for calculation with moving particles or implicit charges locations. This approach is beneficial to large‐scale problems such as molecular statics, molecular dynamics, equilibrium statistics (Monte‐Carlo simulations), molecular docking, and in areas such as magnetism and astrophysics. © 2001 John Wiley & Sons, Inc. J Comput Chem 22: 717–731, 2001
MSINDO parameterization for third‐row transition metals
Authors: Bredow Thomas , Geudtner Gerald , Jug Karl 
Published: October 2004

AbstractThe recently developed MSINDO version of the semiempirical SCF MO method SINDO1 has been parameterized for third‐row transition metals Sc to Zn. The set of reference data used for the previous parameterization of SINDO1 has been substantially increased by incorporating results of recent experiments and first‐principles calculations. A comparison of calculated heats of formation, geometries, ionization potentials, and dipole moments with literature values for more than 200 gas phase molecules is presented. The accuracy of the modified MSINDO version achieved for heats of formation and bond lengths has been considerably improved compared to SINDO1. Small clusters of transition metals and metal oxides were included in the parameterization to ensure accurate results for studies of larger systems. The application of the method to small transition metal complexes that were not included in the parameterization shows that the optimized parameters are transferable to other compounds. © 2001 John Wiley & Sons, Inc. J Comput Chem 22: 861–887, 2001
Application of structure‐based focusing to the estrogen receptor
Authors: Kirchhoff Paul D. , Brown Rob , Kahn Scott , Waldman Marvin , Venkatachalam C. M. 
Published: October 2004

AbstractWe present the Cerius2 Structure‐Based Focusing (SBF) application. This application was applied to the estrogen receptor. A series of three‐dimensional queries were generated for the binding site of the receptor. The queries consist of combinations of hydrogen bond donors and acceptors, and lipophilic features for the binding site along with excluded volume regions occupied by the receptor atoms. A database of 31 ligands with known relative binding affinities for the estrogen receptor was used to examine the selectivity of the queries. The objective of the study was to determine if queries generated by the Cerius2 SBF method could differentiate between the more and less active ligands of the training set. Results are promising, with the generated queries showing greater selectivity toward the more active ligands. © 2001 John Wiley & Sons, Inc. J Comput Chem 22: 993–1003, 2001
Adsorption integral equation via complex approximation with constraints: kernel of general form
Authors: Bushenkov Vladimir A. , Ramalho J. P. Prates , Smirnov Georgi V. 
Published: October 2004

AbstractFor the monolayer adsorption on a homogeneous surface, including arbitrary range lateral interactions, the isotherm can be written as a power series of the Langmuir isotherm. If this isotherm is used as the kernel in the adsorption integral equation, this integral equation can be solved in an analytical form. Because the global isotherm is usually known as a set of experimental values, the use of a numerical method is inevitable. A new numerical method for solving the adsorption integral equation with a kernel of general form is developed. It is based on recent results concerning the structure of the local isotherm and on the ideas of complex approximation with constraints, and allows reduction of the problem under consideration to a linear‐quadratic programming problem. Results of numerical experiments are presented. The method can be useful for the evaluation of the adsorption energy distribution from experimental data. © 2001 John Wiley & Sons, Inc. J Comput Chem 22: 1058–1066, 2001
Analysis of the transferability of atomic multipoles for amino acids in modeling macromolecular charge distribution from fragments
Authors: Kędzierski Pawel , Sokalski W. Andrzej 
Published: October 2004

AbstractCumulative Atomic Multipole Moments were calculated for all natural amino acids and symmetric cyclic hexapeptides within Self‐Consisted Field (SCF) and Density Functional Theory (DFT) approaches using a standard 6‐31G(d,p) basis set. These data were used to analyze in detail the quality and the conformational and the intermolecular transferability of molecular charge distributions expressed in the atomic multipole form. Intermolecular interaction energies were reproduced reasonably by CAMM transformed from other conformations. Good transferability of CAMM based model was also achieved between similar molecular environments, which opens a route to modeling electrostatic effects in highly symmetric (e.g., crystalline) systems. Transferability deficiencies of various charge distribution models were analyzed and attributed to different levels of multipole expansion. © 2001 John Wiley & Sons, Inc. J Comput Chem 22: 1082–1097, 2001
Cationic Closo Carboranes—Promising Weakly Coordinating Ions
Authors: Jemmis Eluvathingal D. , Ramalingam M. , Jayasree Elambalassery G. 
Published: October 2004

AbstractThe unexplored carbon rich cationic closo carboranes, C3Bn−3Hn+1 (n=5, 6, 7, 10, 12) are investigated theoretically. The position isomers were calculated at the B3LYP/6‐31G* level, and the charge distribution in the cluster is estimated by NBO analysis. The criterion of ring‐cap orbital overlap compatibility along with the number of BC, CC, and BB bonds help in explaining the stability order in each category. The most stable isomer is the one with maximum ring‐cap orbital overlap and largest number of BC bonds. The order of relative stability among the trigonal bipyramid is 1c>1b>1a′, where the stability is proportional to the number of CH caps over the small three‐membered ring. The C3B3H6+ isomer with the one allyl C3 group (2b) is more favorable than the one with a cyclopropenyl group (2a). Among the C3B4H7+ isomers the stability order is 3e>3d>3c>3b>3a, which mostly depends on the ring‐cap orbital overlap. In the bicapped square antiprism (4) where there is large number of isomers, the order follows the rule of ring cap compatibility and the number of BC bonds. The order of 5e>5d>5c>5b>5a obtained from the calculations is in perfect agreement with the above sited rules. Equations (1)–(5) devised for estimating the stability of isomers of C3Bn−3Hn+ indicate an increase in stability with cage size. The mono‐positive charge of the isomers is distributed throughout the cage, making them suitable candidates as weakly electrophillic cations. © 2001 John Wiley & Sons, Inc. J Comput Chem 22: 1542–1551, 2001