bluuebunny/crossref_metadata_2025_split huggingface dataset:
Properties of titanium–silver alloys for dental application
Authors: Oh Keun‐Taek , Shim Hyung‐Min , Kim Kyoung‐Nam 
Published: April 2005

AbstractThe purpose of this study was to develop titanium–silver alloys with biocompatibility, high corrosion resistance, and low ion‐release rate, and to evaluate the electrochemical properties of titanium–silver alloys in artificial saliva. Titanium–silver alloys with silver contents ranging from 0 to 4.5 at % in steps of 0.5 at % were designed. The alloys were arc melted, homogenized at 950°C for 72 h, hot rolled to 2 mm in thickness, and finally solution heat treated at 950°C for 1 h and quenched in water. Chemical compositions, phases, hardnesses, electrochemical properties, and the cytotoxicity of the alloys were investigated. The purity of titanium–silver alloys was maintained above 99.9%, because few impurities were introduced through their manufacture. In the case of alloys containing silver in the range 2.0–4.0 at %, the formation of an acicular α phase was observed inside the β phase. The acicular phase got thinner with increasing amounts of silver. This means that silver is a β‐phase stabilizing element in titanium–silver alloys. The hardness value tended to rise with increasing silver content and increased largely over 3.5 at %, and the increase of the hardness value versus pure titanium was about 33%. It is believed that the substantial increases in hardness was due to the effects of solid solution strengthening and of α–β phase transition. Moreover, titanium–silver alloys had higher corrosion resistances than pure titanium. These results mean that silver additions to titanium can improve alloy corrosion resistance. Passive current densities in the potentiodynamic polarization curves were dependent on the chemical compositions of the titanium–silver alloys. However, they did not show a linear relationship with respect to silver contents. Titanium–silver alloys did not show pitting corrosion in artificial saliva. It is believed that silver addition to titanium strengthened the passive film due to titanium dissolution induced by the different electromotive forces of titanium and silver. In the agar overlay test, the cytotoxicity of the titanium–silver alloys and of titanium were none or mild. In summary, titanium–silver alloys had higher mechanical properties and corrosion resistance than titanium, and toxicities that were similar to titanium. Therefore, it is recommended that titanium–silver alloys be adopted cautiously by the biomedical and dental fields. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater
Molecular dynamics simulation of clustered DNA damage sites containing 8‐oxoguanine and abasic site
Authors: Fujimoto Hirofumi , Pinak Miroslav , Nemoto Toshiyuki , O'Neill Peter , Kume Etsuo , Saito Kimiaki , Maekawa Hideaki 
Published: April 2005

AbstractClustered DNA damage sites induced by ionizing radiation have been suggested to have serious consequences to organisms, such as cancer, due to their reduced probability to be repaired by the enzymatic repair machinery of the cell. Although experimental results have revealed that clustered DNA damage sites effectively retard the efficient function of repair enzymes, it remains unclear as to what particular factors influence this retardation. In this study, approaches based on molecular dynamics (MD) simulation have been applied to examine conformational changes and energetic properties of DNA molecules containing clustered damage sites consisting of two lesioned sites, namely 7,8‐dihydro‐8‐oxoguanine (8‐oxoG) and apurinic/apyrimidinic (AP) site, located within a few base pairs of each other. After 1 ns of MD simulation, one of the six DNA molecules containing a clustered damage site develops specific characteristic features: sharp bending at the lesioned site and weakening or complete loss of electrostatic interaction energy between 8‐oxoG and bases located on the complementary strand. From these results it is suggested that these changes would make it difficult for the repair enzyme to bind to the lesions within the clustered damage site and thereby result in a reduction of its repair capacity. © 2005 Wiley Periodicals, Inc. J Comput Chem 26: 788–798, 2005
Carbon boronyls: Species with higher viable possibility than boron carbonyls at the density functional theory
Authors: Li Si‐Dian , Miao Chang‐Qing , Guo Jin‐Chang , Ren Guang‐Ming 
Published: April 2005

AbstractDensity functional theory investigations indicate that carbon boronyls (CBO)n (n = 3–7) are considerably more stable in thermodynamics than their boron carbonyl isomers (BCO)n and exhibit aromaticity throughout the whole series. The extra stabilities of (CBO)n originate from their frontier π molecular orbitals delocalized over the Dnh Cn central rings which are absent in (BCO)n. It is expected that experimental characterization of these (CBO)n species may open a new branch of chemistry on carbon boronyls. © 2005 Wiley Periodicals, Inc. J Comput Chem 26: 799–802, 2005
Decomposition and long‐lasting downregulation of extracellular matrix in perineuronal nets induced by focal cerebral ischemia in rats
Authors: Hobohm Carsten , Günther Albrecht , Grosche Jens , Roßner Steffen , Schneider Dietmar , Brückner Gert 
Published: April 2005

AbstractThe upregulation of extracellular matrix components, especially chondroitin sulfate proteoglycans, after brain injury and stroke is known to accompany the glial reaction, forming repellent scars that hinder axonal growth and the reorganization of the injured neuronal networks. The extracellular matrix associated with perineuronal nets (PNs) in the primarily injured and remote regions has not yet been systematically analyzed. We use the model of permanent middle cerebral artery occlusion (MCAO) to investigate the acute and long‐lasting consequences of ischemia for PNs, related to the damage of neurons and reactions of glial cells, in spontaneously hypertensive rats. Extracellular matrix components associated with PNs around cortical interneurons and neurons in thalamic nuclei were characterized 1, 7, 14, and 35 days after MCAO, using Wisteria floribunda agglutinin (WFA) staining and immunocytochemistry. The degradation of PNs in the infarct core was initiated by loss of WFA‐binding matrix components, indicating the cleavage of glycosaminoglycan chains of chondroitin sulfate proteoglycans. Immunostaining showed the subsequent removal of proteoglycan core proteins within the extending microglia/macrophage invasion zone lasting for 2 weeks after MCAO. In the cortical periinfarct region, delineated by an astrocytic scar against the infarct core, the number of WFA‐stained and proteoglycan core protein‐immunoreactive PNs was permanently reduced. In the homolateral ventroposterior thalamus, the delayed decrease in perineuronal matrix was related to the distribution pattern of activated microglia and massive neuronal degeneration. It can be concluded from these results that complementary to the known upregulation of matrix components in the glial scar, deficits in the expression of the neuron‐associated extracellular matrix develop in the periinfarct and remote regions. These deficits may contribute to the long‐lasting functional impairments after stroke. © 2005 Wiley‐Liss, Inc.
A correlated method for quantifying mixed and dispersed carbon nanotubes: analysis of the Raman band intensities and evidence of wavenumber shift
Authors: Athalin Han , Lefrant Serge 
Published: April 2005

AbstractWe present an experimental investigation of a correlated quantitative analytical method based on advanced Raman spectroscopy. This method was developed for the intensity weight distribution analysis of mixed and dispersed carbon nanotube (CNT) mixtures. For Raman spectroscopy, mixtures of single‐walled CNTs (SWNTs) and multi‐walled CNTs (MWNTs) were prepared and dispersed on a coverslip. Mixtures were made in the range from 1 to 100 mg (wt%) of SWNTs in 100 to 1 mg (wt%) of MWNTs. The ratios of the relative intensities of the Raman bands corresponding to pure SWNTs and pure MWNTs were used for the construction of calibration curves used for quantitative analysis. The relative intensity of the deconvoluted spectral bands shows a characteristic feature at 1350 and 1592 cm−1 which was found to be proportional to the relative amounts of SWNTs and MWNTs in the mixtures. A correlation between the atomic force microscopy images and the tangential mode Raman intensity ratio was used without the need for other analytical techniques. With this feature, it is possible to quantify the different components in the mixed, dispersed or unknown bulk of the CNTs investigated. Copyright © 2005 John Wiley & Sons, Ltd.
Raman spectroscopic identification of single yeast cells
Authors: Rösch Petra , Harz Michaela , Schmitt Michael , Popp Jürgen 
Published: April 2005

AbstractEukaryotes (such as yeasts) and prokaryotes (such as bacteria) differ in size, molecular complexity, etc. By definition, eukaryotic cells store their DNA in a separate internal compartment, the so‐called nucleus. Owing to this molecular compartmentalization, the identification of yeast cells by vibrational spectroscopy at a single‐cell level is challenging. This contribution reports on first results of micro‐Raman analysis together with a hierarchical cluster analysis allowing for an online identification method for yeast cells at a single‐cell level. For the classification analysis, an average spectrum from 10 different measuring points within a single yeast cell was used to overcome the heterogeneity of the yeast cells. Copyright © 2005 John Wiley & Sons, Ltd.
Recent developments in the field of monolithic stationary phases for capillary electrochromatography
Authors: Svec Frantisek 
Published: April 2005

AbstractThis review summarizes the contributions to the rapidly growing area of monolithic columns based on both silica and synthetic polymers for capillary electrochromatography and chip electrochromatography, with a focus on those published during the year 2004. A wide variety of both modified approaches to the “old” monoliths and new monoliths have been reported despite the very short period of time covered. This demonstrates that monolithic stationary phases have become a well‐established format in the field of electrochromatography. The simplicity of their preparation as well as the good control over their porous properties and surface chemistries make the monolithic separation media an attractive alternative to capillary columns packed with particulate materials.
Influence of steric hindrance on enantioseparation of Dns‐amino acids and pesticides on terguride based chiral selectors in capillary electrophoresis
Authors: Honzátko Aleš , Cvak Jan , Vaingátová Silvie , Flieger Miroslav 
Published: April 2005

AbstractThree urea derivatives of ergoline‐based chiral selectors (CSs), differing in the size of the urea side chain, i. e. dimethyl‐ (CSI), diethyl‐ (CSII), and diisopropylurea (CSIII), were used to study the effect of steric hindrance on the enantioseparation of dansyl amino acids (Dns‐AAs), pesticides, and mandelic acid under condition of capillary electrophoresis (CE) in linear polyacrylamide coated capillaries. A mixture of organic modifiers (MeOH/THF, 4 : 1 v/v) in a BGE consisting of 100 mM β‐alanine‐acetate was used to increase the solubility of CSs up to 25 mM. The capillary was filled with CS (high UV absorption), and the inlet and outlet vials contained buffer solutions only. The best enantioseparation of Dns‐AAs was achieved on CSI. Increased steric hindrance of the chiral binding site led to reduction of both enantioselectivity and resolution. The opposite pattern was observed for the separation of mandelic acid enantiomers, where the best enantioseparation and resolution was obtained with CSIII. Most of the pesticides studied reached maximum selectivity on the diethylurea ergoline derivative (CSII). Enantioseparation of fenoxaprop was found to be independent of steric hindrance.
Wilson's disease presenting with an unusual cough
Authors: Crone Nathan E. , Jinnah H. A. , Reich Stephen G. 
Published: April 2005

AbstractA 26‐year‐old man developed an unusual repetitive, nonproductive cough. Extensive pulmonary and otolaryngology investigations failed to disclose a cause. It was only after he developed additional neurological manifestations ultimately leading to the diagnosis of Wilson's disease (WD) that a neurological basis for the cough was suspected. Features of the cough suggest it was a form of respiratory dyskinesia, a previously unreported presentation of WD. © 2005 Movement Disorder Society
Interaction of the conserved meiotic regulators, BOULE (BOL) and PUMILIO‐2 (PUM2)
Authors: Urano Jun , Fox Mark S. , Reijo Pera Renee A. 
Published: April 2005

AbstractGerm cell development is complex; it encompasses specification of germ cell fate, mitotic replication of early germ cell populations, and meiotic and postmeiotic development. Meiosis alone may require several hundred genes, including homologs of the BOULE (BOL) and PUMILIO (PUM) gene families. Both BOL and PUM homologs encode germ cell specific RNA binding proteins in diverse organisms where they are required for germ cell development. Here, we demonstrate that human BOL forms homodimers and is able to interact with a PUMILIO homolog, PUM2. We mapped the domain of BOL that is required for dimerization and for interaction with PUM2. We also show that BOL and PUM2 can form a complex on a subset of PUM2 RNA targets that is distinct from targets bound by PUM2 and another deleted in azoospermia (DAZ) family member, DAZ‐like (DAZL). This suggests that RNA sequences bound by PUM2 may be determined by protein interactions. This data also suggests that although the BOL, DAZ, and DAZL proteins are all members of the same gene family, they may function in distinct molecular complexes during human germ cell development. Mol. Reprod. Dev. © 2005 Wiley‐Liss, Inc.
The analysis of telomere length and telomerase activity in cloned pigs and cows
Authors: Jeon H.Y. , Hyun S.H. , Lee G.S. , Kim H.S. , Kim S. , Jeong Y.W. , Kang S.K. , Lee B.C. , Han J.Y. , Ahn C. , Hwang W.S. 
Published: April 2005

AbstractInefficiency in the production of cloned animals is most likely due to epigenetic reprogramming errors after somatic cell nuclear transfer (SCNT). In order to investigate whether nuclear reprogramming restores cellular age of donor cells after SCNT, we measured telomere length and telomerase activity in cloned pigs and cattle. In normal pigs and cattle, the mean telomere length was decreased with biological aging. In cloned or transgenic cloned piglets, the mean telomere length was elongated compared to nuclear donor fetal fibroblasts and age‐matched normal piglets. In cloned cattle, no increases in mean telomere length were observed compared to nuclear donor adult fibroblasts. In terms of telomerase activity, significant activity was observed in nuclear donor cells and normal tissues from adult or new‐born pigs and cattle, with relatively higher activity in the porcine tissues compared to the bovine tissues. Cloned calves and piglets showed the same level of telomerase activity as their respective donor cells. In addition, no difference in telomerase activity was observed between normal and transgenic cloned piglets. However, increased telomerase activity was observed in porcine SCNT blastocysts compared to nuclear donor cells and in vitro fertilization (IVF)‐derived blastocysts, suggesting that the elongation of telomere lengths observed in cloned piglets could be due to the presence of higher telomerase activity in SCNT blastocysts. In conclusion, gathering from the comparative studies with cattle, we were able to demonstrate that telomere length in cloned piglets was rebuilt or elongated with the use of cultured donor fetal fibroblasts. Mol. Reprod. Dev. © 2005 Wiley‐Liss, Inc.
Intraoviductal introduction of plasmid DNA and subsequent electroporation for efficient in vivo gene transfer to murine oviductal epithelium
Authors: Sato Masahiro 
Published: April 2005

AbstractVarious growth factors and proteins produced by oviductal cells have been demonstrated to interact with developing embryos. However, little is known concerning the function of mammalian oviducts at the molecular biological level. This may be partly due to lack of efficient gene transfer to oviductal cells. In this study, we developed an efficient method for transfection of oviductal epithelium using in vivo electroporation (EP) in mice. One microliter of solution containing enhanced green fluorescent protein (EGFP) expression plasmid (0.5 μg) and 0.05% trypan blue (TB) were directly introduced into the ampulla of the eCG‐hCG‐treated B6C3F1 females at embryonic day (E) 0.6 of pregnancy (corresponding to 14:00–15:00 of the day the plug was recognized). The entire oviduct was then electroporated using tweezer‐type electrodes attached to a T820 electroporator (BTX Genetronics, Inc., San Diego, CA) with eight square‐wave pulses, 50 V in strength and 50 msec in duration. On E 3.4, embryos at morula/early blastocyst stages were collected and their number, morphology, and EGFP‐derived fluorescence recorded. Fluorescence in oviducts was also examined. In some cases, these fluorescent oviducts were subjected to cryostat sectioning. Strong fluorescence was observed in some of the oviductal epithelia, with a maximum level of 36%. Neither the number nor morphology of the collected embryos was affected by EP. Some embryos possessed fluorescence in the blastocoel, but not cytoplasm, suggesting incorporation of EGFP present in the oviductal luminal fluid. This system may enable development of new factors regulating development of preimplantation embryos and offers the prospect of a new approach to understanding oviductal function. Mol. Reprod. Dev. © 2005 Wiley‐Liss, Inc.
Comparing the function of the corticospinal system in different species: Organizational differences for motor specialization?
Authors: Lemon Roger N. , Griffiths James 
Published: April 2005

AbstractAn appreciation of the comparative functions of the corticospinal tract is of direct relevance to the understanding of how results from animal models can advance knowledge of the human motor system and its disorders. Two critical functions of the corticospinal tract are discussed: first, the role of descending projections to the dorsal horn in the control of sensory afferent input, and second, the capacity of direct cortico‐motoneuronal projections to support voluntary execution of skilled hand and finger movements. We stress that there are some important differences in corticospinal projections from different cortical regions within a particular species and that these projections support different functions. Therefore, any differences in the organization of corticospinal projections across species may well reflect differences in their functional roles. Such differences most likely reflect features of the sensorimotor behavior that are characteristic of that species. Insights into corticospinal function in different animal models are of direct relevance to understanding the human motor system, providing they are interpreted in relation to the functions they underpin in a given model. Studies in non‐human primates will continue to be needed for understanding special features of the human motor system, including feed‐forward control of skilled hand movements. These movements are often particularly vulnerable to neurological disease, including stroke, cerebral palsy, movement disorders, spinal injury, and motor neuron disease. Muscle Nerve, 2005
Phase diagram and enhanced piezoelectricity in the strontium titanate doped potassium–sodium niobate solid solution
Authors: Wang Ruiping , Xie Rong‐Jun , Hanada Kotaro , Matsusaki Kunio , Bando Hiroshi , Itoh Mitsuru 
Published: April 2005

AbstractThe dielectric and the piezoelectric properties of the (1–x)(Na0.5K0.5)NbO3–xSrTiO3 ceramics, densified by the Spark‐Plasma‐Sintering method, have been studied. A phase diagram was established from the temperature dependence of the dielectric constant. A tetragonal–orthorhombic morpho‐tropic phase boundary (MPB) was found at x ∼ 0.05. Around the MPB, piezoelectric properties were greatly improved. The origin for the enhanced piezoelectricity has been proposed. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Quantum chemical studies on molecular structural conformations and hydrated forms of salicylamide and O‐hydroxybenzoyl cyanide
Authors: Anandan K. , Kolandaivel P. , Kumaresan R. 
Published: April 2005

AbstractAb initio and density functional theory (DFT) methods have been employed to study the molecular structural conformations and hydrated forms of both salicylamide (SAM) and O‐hydroxybenzoyl cyanide (OHBC). Molecular geometries and energetics have been obtained in the gaseous phase by employing the Møller–Plesset type 2 MP2/6‐311G(2d,2p)and B3LYP/6‐311G(2d,2p)levels of theory. The presence of an electron‐releasing group (SAM) leads to an increase in the energy of the molecular system, while the presence of an electron‐withdrawing group (OHBC) drastically decreases the energy. Chemical reactivity parameters (η and μ) have been calculated using the energy values of the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) obtained at the Hartree–Fock (HF)/6‐311G(2d,2p)level of theory for all the conformers and the principle of maximum hardness (MHP) has been tested. The condensed Fukui functions have been calculated using the atomic charges obtained through the natural bond orbital (NBO) analysis scheme for all the optimized structures at the B3LYP/6‐311G(2d,2p)level of theory, and the most reactive sites of the molecules have been identified. Nuclear magnetic resonance (NMR) studies have been carried out at the B3LYP/6‐311G(2d,2p)level of theory for all the conformers in the gaseous phase on the basis of the method of Cheeseman and coworkers. The calculated chemical shift values have been used to discuss the delocalization activity of the electron clouds. The dimeric structures of the most stable conformers of both SAM and OHBC in the gaseous phase have been optimized at the B3LYP/6‐311G(2d,2p)level of theory, and the interaction energies have been calculated. The most stable conformers of both compounds bear an intramolecular hydrogen bond, which gives rise to the formation of a pseudo‐aromatic ring. These conformers have been allowed to interact with the water molecule. Special emphasis has been given to analysis of the intermolecular hydrogen bonds of the hydrated conformers. Self‐consistent reaction field (SCRF) theory has been employed to optimize all the conformers in the aqueous phase (ε = 78.39) at the B3LYP/6‐311G(2d,2p)level of theory, and the solvent effect has been studied. Vibrational frequency analysis has been performed for all the optimized structures at MP2/6‐311G(2d,2p)level of theory, and the stationary points corresponding to local minima without imaginary frequencies have been obtained for all the molecular structures. © 2005 Wiley Periodicals, Inc. Int J Quantum Chem, 2005
Structural phases of coupled polyacetylene chains with impurities
Authors: Guimarães Paulo Henrique Alves , Silva Geraldo Magela E 
Published: April 2005

AbstractThe study of quasi‐particles in conducting polymers is concentrated in single‐chain works. It is shown in the present study that interchain interactions can be determinant in the relative presence of solitons, polarons, or bipolarons in conjugated polymers. We consider a modified version of the SSH model for polyacetylene. The results show that the presence of different impurities, bonded to different chains sites, led to quite different relative chains configurations and phases related to bond alignment order, presence of quasi‐particles, and their respective charges. © 2005 Wiley Periodicals, Inc. Int J Quantum Chem, 2005