bluuebunny/crossref_metadata_2025_split huggingface dataset:
Electrochemical processes of nucleation and growth of calcium phosphate on titanium supported by real‐time quartz crystal microbalance measurements and X‐ray photoelectron spectroscopy analysis
Authors: Eliaz Noam , Kopelovitch William , Burstein Larisa , Kobayashi Equo , Hanawa Takao 
Published: June 2008

AbstractReal‐time, in situ electrochemical quartz crystal microbalance (EQCM) measurements are conducted to better understand the electrocrystallization of calcium phosphates (CaP) on CP‐Ti. X‐ray photoelectron spectroscopy is used to identify the exact phase deposited, so that reliable estimation of the electrochemical processes involved is made. Analysis of the integrated intensity of the oxygen shake‐up peaks, in combination with the determination of Ca/P and O/Ca atomic ratios, enables to determine unambiguously that the octacalcium phosphate (OCP) is formed. Its role as a precursor to hydroxyapatite (HAp) is discussed. After an incubation period, the process by which OCP is formed follows a Faradaic behavior. The incubation time may be related to the need for local increase of pH before precipitation from solution can occur. The standard enthalpy of activation is ∼40 kJ/mol, which excludes diffusion‐controlled processes from being rate determining. The OCP deposit has thickness ≈0.61 μm, apparent density ≈ 0.95 g/cm3, 63.6% porosity, and deposition rate of 23.5 ng/(cm2 s) or 15 nm/min. The low‐equivalent weight value of 20.5 g/equiv, and the associated remarkably high number of electrons transferred in the reaction n ≈ 24, indicates that most of the current is consumed either by electrolysis of water or by a complex set of parasitic reactions. The low‐solubility product allows precipitation of CaP even at relatively low concentrations of calcium and phosphate/hydrogen phosphate ions. It is shown that HAp most likely forms via transformation of precursor phases, such as OCP, rather than directly. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res, 2009
Quantitative analysis of osteoblast‐like cells (MG63) morphology on nanogrooved substrata with various groove and ridge dimensions
Authors: Yang Jung‐Yen , Ting Yen‐Chung , Lai Juin‐Yih , Liu Hsuan‐Liang , Fang Hsu‐Wei , Tsai Wei‐Bor 
Published: June 2008

AbstractNanotextured silicon substrata with parallel ridges separated by grooves with equal width from 90 to 500 nm, were fabricated by electron beam lithography and dry etching techniques. Osteoblast‐like cells, MG‐63, were cultured on the sterilized nanopatterned substrata for 4 or 24 h, and then imaged by scanning electron microscopy. The influence of substrate topography on cell morphology was analyzed by image software. We found the initially cells spread faster on the nanopatterned surfaces than on the flat surface, suggesting that surface anisotropic feature facilitates initial cell extension along its direction. However, because of inhibition of cell lateral expansion across nanogrooved surfaces, the cells on the nanogrooved surface did not further expand laterally, and cell spreading area was less than that on the flat surface after 24 h of incubation. Cells elongated and aligned along the direction of grooves on all the nanopatterned substrata. Furthermore, fluorescence staining of cell nuclei indicated that the nuclei of the cells cultured on the nanopatterned surfaces also displayed a more elongated and aligned morphology along the direction of the grooves. Since cell shape and orientation influence cell functions and alignment of extracellular matrix secreted by cells, our results may provide the information regarding responses of osteoblasts to the nanostructure of collagen fibrils, and benefit bone tissue engineering and surface design of orthopedic implants. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res, 2009
Effect of ring‐opening polymerization condition on the characteristic and mechanical properties of hydroxyapatite/poly(ethylene glutarate) biomaterials
Authors: Monvisade Pathavuth , Siriphannon Punnama , Tapcharoen Walailak 
Published: June 2008

AbstractPreparation of hydroxyapatite/poly(ethylene glutarate) (HAp/PEG) composites was carried out by ring‐opening polymerization (ROP) of cyclic oligo(ethylene glutarate) in porous HAp scaffolds using various reaction temperatures and times. The content of ROP‐PEG interpenetrated into the porous HAp scaffold was about 13–18 wt % with the values of number average molecular weight ($ \overline {M_{\rm n} } $) and weight average molecular weight ($ \overline {M_{\rm W} } $) of 2120–3630 and 2760–5250 g/mol, respectively. The increase in polymerization time and temperature brought about increase in molecular weight of ROP‐PEG, but decrease in its content. Compressive strength and compressive modulus of the HAp/PEG composites were about 5.8–20.1 and 105–208 MPa, respectively. These mechanical properties depend upon the effects of distribution, content, and molecular weight of ROP‐PEG in the composites. In vitro bioactivity of the HAp/PEG composites was studied by soaking them in simulated body fluid (SBF) for 28 days. The formation of HAp nanocrystal on the composite surfaces through the consumption of calcium and phosphorus from the SBF solution was observed after soaking, indicating the bioactivity of these HAp/PEG composites. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res, 2009
Development of a self‐cleaning sensor membrane for implantable biosensors
Authors: Gant Rebecca M. , Hou Yaping , Grunlan Melissa A. , Coté Gerard L. 
Published: June 2008

AbstractFibrous tissue encapsulation may slow the diffusion of the target analyte to an implanted sensor and compromise the optical signal. Poly(N‐isopropylacrylamide) (PNIPAAm) hydrogels are thermoresponsive, exhibiting temperature‐modulated swelling behavior that could be used to prevent biofouling. Unfortunately, PNIPAAm hydrogels are limited by poor mechanical strength. In this study, a unique thermoresponsive nanocomposite hydrogel was developed to create a mechanically robust self‐cleaning sensor membrane for implantable biosensors. This hydrogel was prepared by the photochemical cure of an aqueous solution of NIPAAm and copoly(dimethylsiloxane/methylvinylsiloxane) colloidal nanoparticles (∼219 nm). At temperatures above the volume phase transition temperature (VPTT) of approximately 33–34°C, the hydrogel deswells and becomes hydrophobic, whereas lowering the temperature below the VPTT causes the hydrogel to swell and become hydrophilic. The potential of this material to minimize biofouling via temperature‐modulation while maintaining sensor viability was investigated using glucose as a target analyte. PNIPAAm composite hydrogels with and without poration were compared to a pure PNIPAAm hydrogel and a nonthermoresponsive poly(ethylene glycol) (PEG) hydrogel. Poration led to a substantial increase in diffusion. Cycling the temperature of the nanocomposite hydrogels around the VPTT caused significant detachment of GFP‐H2B 3T3 fibroblast cells. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res, 2009
Preparation and characterization of bioactive calcium silicate and poly(ϵ‐caprolactone) nanocomposite for bone tissue regeneration
Authors: Wei Jie , Heo S. J. , Liu Changsheng , Kim D. H. , Kim S. E. , Hyun Y. T. , Shin Ji‐Wang , Shin Jung‐Woog 
Published: June 2008

AbstractA novel biocomposite of nanosized calcium silicate (n‐CS) and poly(ϵ‐caprolactone) (PCL) was successfully fabricated directly using n‐CS slurry, not dried n‐CS powder, in a solvent‐casting method. The in vitro bioactivity of the composite was evaluated by investigating the apatite‐forming ability in simulated body fluid. A proliferation assay with mouse L929 fibroblasts was used to test the in vitro biocompatibility. The composition, hydrophilicity, and mechanical properties were also evaluated. Results suggest that the incorporation of n‐CS could significantly improve the hydrophilicity, compressive strength, and elastic modulus of n‐CS/PCL composites, with the enhancements mainly dependent on n‐CS content. The n‐CS/PCL composites exhibit excellent in vitro bioactivity, with surface apatite formation for 40% (w/w) n‐CS (C40) exceeding that of 20% (w/w) n‐CS (C20) at 7 and 14 days. The Ca/P ratios of apatite formed on C20 and C40 surfaces were 1.58 and 1.61, respectively, indicating nonstoichiometric apatite with defective structure. Composites demonstrated significantly better cell attachment and proliferation than that of PCL alone, with C40 demonstrating the best bioactivity. The apatite layers that formed on the composite surfaces facilitated cell attachment (4 h) and proliferation during the early stages (1 and 4 days). Collectively, these results suggest that the incorporation of n‐CS produces biocomposites with enhanced bioactivity and biocompatibility. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res, 2009
Inorganic phosphate stimulates the toxic effects of Tl+ in rat liver mitochondria
Authors: Korotkov Sergey M. , Emel'yanova Larisa V. , Yagodina Olga V. 
Published: June 2008

AbstractWe studied action of inorganic phosphate (Pi) on toxic effects of Tl+ in isolated rat liver mitochondria. This is a convenient model to study the toxicity of heavy metals. Pi markedly retarded contraction of energized mitochondria swollen in the TlNO3 medium and even stronger stimulated swelling and state 4 of succinate‐energized mitochondria in the TlNO3 medium. A valinomycin‐induced decrease of K+‐diffusion potential was also accelerated by Tl+ in the presence of Pi. The mitochondrial permeability transition pore in the medium containing Ca2+, TlNO3, and nitrates of univalent cations was distinctly stimulated by Pi. However, Pi did not affect both the Tl+‐stimulated swelling of nonenergized mitochondria in the TlNO3 medium and swelling of energized mitochondria in the Tl acetate medium. Respiration stimulated by 2,4‐dinitrophenol and monoamine oxidase activity of energized mitochondria were not affected by Tl+ regardless of the presence of Pi. We suggested that stimulation by Pi of toxic action of Tl+ in mitochondria and cells could be due to even greater enhancement of uncoupling of mitochondria as shown by an additional increase of swelling and state 4, and in the greater probability of opening of MPTP in the presence of Pi and Ca2+. © 2008 Wiley Periodicals, Inc. J Biochem Mol Toxicol 22:148–157, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/jbt.20215
Preparation and adsorption characteristic of polymeric microsphere with strong adsorbability for creatinine
Authors: Gao Baojiao , Yang Ying , Wang Jian , Zhang Yan 
Published: June 2008

AbstractCross‐linking terpolymer microspheres (HEMA/NVP/MBA; it can also be designated as HEMA/NVP because HEMA and NVP are main components) with an average diameter of 180 µm, were prepared via inverse suspension copolymerization by using 2‐hydroxyethyl methacrylate (HEMA) and N‐vinylpyrrolidone (NVP) as monomers and N,N′‐methylene bisacrylamide (MBA) as cross‐linked agent. The microsphere HEMA/NVP was chemically modified with 3,5‐dinitrobenzoyl chloride (DNBC), and the functional microsphere DNBZ‐HEMA/NVP, on which a great number of 3,5‐dinitrobenzoate group (DNBZ) were bound, was obtained. The functional microsphere DNBZ‐HEMA/NVP were characterized with FTIR and the chemical analysis method. The adsorption characteristics and mechanism of the absorption of DNBZ‐HEMA/NVP for creatine was mainly studied. The results of static adsorption experiments show that the functional microsphere DNBZ‐HEMA/NVP has very strong adsorption ability for creatinine, and the saturated adsorption amount is 25 mg/g. The adsorption capacity of the functional microsphere DNBZ‐HEMA/NVP for creatinine is enhanced 20 times as against unmodified microsphere HEMA/NVP. The adsorption capacity is smaller, at lower and higher pH, and has a maximum as pH 8.5. The higher the salinity of the medium, the smaller the adsorption capacity. The adsorption capacity decreases with increasing temperature. The study results show that the adsorption of the microsphere DNBZ‐HEMA/NVP for creatinine is ascribed to a chemical adsorption by driving of electrostatic interaction. © 2008 Wiley Periodicals, Inc. J Biochem Mol Toxicol 22:166–174, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/jbt.20221
Caffeic acid protects human peripheral blood lymphocytes against gamma radiation‐induced cellular damage
Authors: Devipriya Nagarajan , Sudheer Adluri Ram , Menon Venugopal P. 
Published: June 2008

AbstractIn the present study, we investigated in vitro radioprotective potential of caffeic acid (CA), a naturally occurring catecholic acid against gamma radiation‐induced cellular changes. Different concentrations of CA (5.5, 11, 22, 44, 66, and 88 µM) were incubated with lymphocytes for 30 min prior to γ‐irradiation, and micronuclei (MN) scoring and comet assay were performed to fix the effective concentration of CA against γ‐irradiation. Among all concentrations, 66 µM of CA showed the optimum protection by effectively decreasing the MN frequencies and comet attributes. From the above‐mentioned results, 66 µM of CA was selected as the effective concentration and was further used to investigate its radioprotective efficacy. For that purpose, a separate experiment was carried out on the lymphocytes in which lymphocytes were preincubated with CA (66 µM) and were exposed to different doses of radiation (1, 2, 3, and 4 Gy). Genetic damage (MN, dicentric aberration, and comet attributes) and biochemical changes were measured. Gamma‐irradiated lymphocytes showed a dose‐dependent increase in the genetic damage and thiobarbituric acid reactive substances, accompanied by the significant decrease in the antioxidant status, whereas CA pretreatment positively modulated all the radiation‐induced changes through its antioxidant potential. The current study demonstrates that CA is effective in protecting lymphocytes against radiation‐induced toxicity and encourages further in vivo study to evaluate radioprotective efficacy of CA. © 2008 Wiley Periodicals, Inc. J Biochem Mol Toxicol 22:175–186, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/jbt.20228
Distribution of SH‐SY5Y human neuroblastoma cells in the cell cycle following exposure to organophosphorus compounds
Authors: Carlson Kent , Ehrich Marion 
Published: June 2008

AbstractThe current study investigated the relationship of the cell cycle phase (as G0/G1, S, and G2/M) and cytotoxicity (as sub‐G1 DNA) to determine whether alterations in cell replication were associated with organophosphate (OP) compound induced cytotoxicity. Results demonstrated that, overall, OP compound‐‐induced cell cycle changes were variable and depended on the OP compound, exposure concentration, and temporal relationship to cytotoxicity. Noncytotoxic OP compound treatments substantially decreased the percentage of cells in S phase of the cell cycle when compared to controls. A corresponding increase was seen in the percent of cells in G0/G1 phase of the cell cycle. In the precytotoxic interval of exposure, most cytotoxic OP compound treatments substantially decreased the percentage of cells in G2/M phase of the cell cycle. Corresponding increases were seen primarily in G0/G1 phase cells. Effects on cells in S stage of the cell cycle varied with the OP compound. In the during cytotoxic interval of exposure, most cytotoxic OP compound treatments substantially increased the percentage of cells in S phase of the cell cycle. A corresponding decrease in the percent of cells in G0/G1 stage of the cell cycle was observed. Furthermore, treatments either increased or decreased the percentage of cells in G2/M phase of the cell cycle when compared to controls, with decreases more likely with the most cytotoxic OP compound exposures. Overall, the in vitro data suggest that exposure to OP compounds can alter the cell cycle status of SH‐SY5Y neuroblastoma cells depending on compound, concentration, and interval from initial exposure. Changes in cell cycle, however, did not differentiate between OP compounds that are known for their ability to acutely inhibit acetylcholinesterase versus those inducing type I and type II delayed neurotoxicity. © 2008 Wiley Periodicals, Inc. J Biochem Mol Toxicol 22:187–201, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/jbt.20229
Cardiotoxin III‐induced apoptosis is mediated by Ca2+‐dependent caspase‐12 activation in K562 cells
Authors: Yang Sheng‐Huei , Chien Ching‐Ming , Chang Long‐Sen , Lin Shinne‐Ren 
Published: June 2008

AbstractCardiotoxin III (CTX III), a basic polypeptide with 60 amino acid residues isolated from Naja naja atra venom, has been reported to have anticancer activity. When K562 cells were treated with CTX III, cytosolic calcium concentration was rapidly and persistently increased. This CTX III‐induced cell death was partially reversed by pretreatment with BAPTA/AM (20 µM), a chelator of intracellular Ca2+. Moreover, CTX III‐induced apoptotic signals, such as caspase‐12 and c‐Jun N‐terminal kinase (JNK) activation, were induced in a time‐dependent manner and inhibited by BAPTA/AM. In contrast, the neutral protease µ‐calpain, a key enzyme in endoplasmic reticulum (ER) stress‐related apoptosis via caspase‐12 activation, was unchanged during apoptosis. Taken together, our findings suggest CTX III‐induced apoptosis is triggered by Ca2+ influx, then activated caspase‐12 and JNK through µ‐calpain‐independent cascade, and consequently caused apoptosis. © 2008 Wiley Periodicals, Inc. J Biochem Mol Toxicol 22:209–218, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/jbt.20231
On list‐coloring outerplanar graphs
Authors: Hutchinson Joan P. 
Published: June 2008

AbstractWe prove that a 2‐connected, outerplanar bipartite graph (respectively, outerplanar near‐triangulation) with a list of colors L (v ) for each vertex v such that $|L(v)|\geq\min\{{\deg}(v),4\}$ (resp., $|L(v)|\geq{\min}\{{\deg}(v),5\}$) can be L‐list‐colored (except when the graph is K3 with identical 2‐lists). These results are best possible for each condition in the hypotheses and bounds. © 2008 Wiley Periodicals, Inc. J Graph Theory 59: 59–74, 2008
An improved upper bound on the crossing number of the hypercube
Authors: Faria Luerbio , Herrera de Figueiredo Celina Miraglia , Sýkora Ondrej , Vrt'o Imrich 
Published: June 2008

AbstractWe draw the n‐dimensional hypercube in the plane with ${5\over 32}4^{n}-\lfloor{{{{n}^{2}+1}\over 2}}\rfloor {2}^{n-2}$ crossings, which improves the previous best estimation and coincides with the long conjectured upper bound of Erdös and Guy. © 2008 Wiley Periodicals, Inc. J Graph Theory 59: 145–161, 2008
Radiosynthesis of [18F]DPA‐714, a selective radioligand for imaging the translocator protein (18 kDa) with PET
Authors: Damont Annelaure , Hinnen Françoise , Kuhnast Bertrand , Schöllhorn‐Peyronneau Marie‐Anne , James Michelle , Luus Christopher , Tavitian Bertrand , Kassiou Michael , Dollé Frédéric 
Published: June 2008

AbstractRecently, a novel series of 2‐phenylpyrazolo[1,5‐a]pyrimidineacetamides has been reported as selective ligands of the translocator protein (18 kDa). Within this series, DPA‐714 (N,N‐diethyl‐2‐(2‐(4‐(2‐fluoroethoxy)phenyl)‐5,7‐dimethylpyrazolo[1,5‐a]pyrimidin‐3‐yl)acetamide, Ki=7.0 nM) is a compound, which had been designed with a fluorine atom in its structure, allowing labelling with fluorine‐18 (half‐life: 109.8 min) and in vivo imaging using positron emission tomography. DPA‐714 and its tosyloxy derivative (N,N‐diethyl‐2‐(2‐(4‐(2‐toluenesulfonyloxyethoxy)phenyl)‐5,7‐dimethylpyrazolo[1,5‐a]pyrimidin‐3‐yl)acetamide) as precursor for the labelling with fluorine‐18 were synthesized in two steps from DPA‐713 (N,N‐diethyl‐2‐(2‐(4‐methoxyphenyl)‐5,7‐dimethylpyrazolo[1,5‐a]pyrimidin‐3‐yl)acetamide) and obtained in 32 and 42% yields, respectively. [18F]DPA‐714 was synthesized using a simple one‐step process (a tosyloxy‐for‐fluorine nucleophilic aliphatic substitution), which has been fully automated on our Zymate‐XP robotic system. It involves: (A) reaction of K[18F]F‐Kryptofix®222 with the tosyloxy precursor (4.5–5.0 mg, 8.2–9.1 µmol) at 165°C for 5 min in dimethyl sufloxide (0.6 mL) followed by (B) C18 PrepSep cartridge pre‐purification and finally (C) semi‐preparative high‐performance liquid chromatography (HPLC) purification on a Waters X‐Terra™ RP18. Typically, 5.6–7.4 GBq of [18F]DPA‐714 (>95% chemically and radiochemically pure) could be obtained with specific radioactivities ranging from 37 to 111 GBq/µmol within 85–90 min (HPLC purification and SepPak®‐based formulation included), starting from a 37 GBq [18F]fluoride batch (overall non‐decay‐corrected and isolated radiochemical yield: 15–20%). Copyright © 2008 John Wiley & Sons, Ltd.
Functional genital morphology of armored spiders (Arachnida: Araneae: Tetrablemmidae)
Authors: Burger Matthias 
Published: June 2008

AbstractThis study describes the female genitalia of the tetrablemmid spiders Brignoliella acuminata, Monoblemma muchmorei, Caraimatta sbordonii, Tetrablemma magister, and Ablemma unicornis by means of serial semi‐thin sections and scanning electron microscopy and compares the results with previous findings on Indicoblemma lannaianum. Furthermore, the male palps and chelicerae are briefly described. The general vulval organization of females is complex and shows similarities in all of the investigated species. The copulatory orifice is situated near the posterior margin of the pulmonary plate. The opening of the uterus externus lies between the pulmonary and the postgenital plate. Paired copulatory ducts lead to sac‐like receptacula. Except for A. unicornis, the male emboli of all investigated species are elongated and thread‐like. However, they are too short to reach the receptacula. Hence, the spermatozoa have to be deposited inside the copulatory ducts. The same situation was also found in I. lannaianum. Females of this species store sperm encapsulated in secretory balls in their receptacula. The secretion is produced by glands adjoining the receptacula. The presence of paired fertilization ducts and spermatozoa in the uterus internus suggested that fertilization takes place internally in I. lannaianum. Secretory balls in the receptacula are found in all of the investigated species in this study, showing that sperm are stored in the same way. The place of fertilization may also be identical since dark particles, presumably spermatozoa, are located in the uterus internus of all investigated species except for T. magister. However, fertilization ducts are only found in B. acuminata and M. muchmorei. A sclerotized central process with attached muscles is present in A. unicornis, M. muchmorei, C. sbordonii and T. magister. Only in A. unicornis does the central process show an internal lumen and hold spermatozoa. In the other species, it could be used to lock the uterus during copulation in order to prevent sperm from getting into it as suggested for certain oonopid species. The uterus externus of all investigated species shows a sclerotized dorsal fold with attached muscles, previously described as “inner vulval plate.” Contractions of the muscles lead to a widening of the dorsal fold, thus creating enough space for the large oocytes to pass the narrow uterus externus. The males of all investigated species have apophyses on their chelicerae. At least in B. acuminata and A. unicornis, where females have paired grooves on the preanal plate, these apophyses allow males to grasp the female during copulation as described for I. lannaianum. © 2008 Wiley‐Liss, Inc.