bluuebunny/crossref_metadata_2025 huggingface dataset:
Synthesis of urethane oils from palm oil and waste PET bottles
Authors: Saravari O. , Pathomwattanasak K. , Pimpan V.
Published: April 2007

Waste PET bottles were depolymerized by propylene glycol at a weight ratio of PET to propylene glycol of 37.5 : 62.5, using zinc acetate as a catalyst. The glycolyzed product, consisting of oligomeric diols with a number–average molecular weight range of 240–1107, was obtained. It was further reacted with palm oil and tolylene diisocyanate to obtain urethane oils at hydroxyl to isocyanate ratios from 1 : 1 to 1 : 0.8, with and without methanol acting as a blocking agent. It was found that all the synthesized urethane oils were yellowish transparent liquids of low molecular weights. A lower isocyanate content or the presence of a blocking agent resulted in higher viscosity, higher molecular weight, and shorter drying time. The films of all synthesized urethane oils exhibited good hardness, excellent flexibility, and high impact strength. They also showed excellent water resistance, good acid resistance but only fair alkali resistance. Moreover, these prepared urethane oils had better adhesion compared with those of the commercial urethane oil. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007
Polymeric decontaminant: N,N‐dichloro poly(styrene‐co‐divinyl benzene) sulfonamide—synthesis, characterization and efficacy against simulant of sulfur mustard
Authors: Gutch P. K. , Shrivastava R. K. , Dubey D. K.
Published: April 2007

N,N‐Dichloro poly(styrene‐co‐divinylbenzene) sulfonamide (1) reacts with 2‐chloro ethyl phenyl sulfide (2), a simulant of sulfur mustard (SM), at room temperature, yielding corresponding nontoxic sulfones and sulfoxides in aqueous as well as aprotic medium. The decontamination reaction was monitored by gas chromatography, and products were identified by gas chromatography–mass spectrometry. N,N‐dichloro poly(styrene‐co‐divinylbenzene) sulfonamide was synthesized by three steps from a commercial starting material sulfonate cation‐exchange resin and characterized by FTIR, and TGA, and compressive strength by universal testing machine. The positive chlorine content of this polymer was checked by standard iodometry titration. The synthesized positive chlorine compound is observed to be a promising against a simulant of SM, chiefly in the situation where use of aqueous medium is precluded. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007
Simultaneous graft copolymerization of 2‐hydroxyethyl methacrylate and acrylic acid onto polydimethylsiloxane surfaces using a two‐step plasma treatment
Authors: Karkhaneh A. , Mirzadeh H. , Ghaffariyeh A. R.
Published: April 2007

Acrylic acid (AAc) and 2‐hydroxyethyl methacrylate (HEMA) mixtures were simultaneously grafted onto the surfaces of polydimethylsiloxane (PDMS) films using a two‐step oxygen plasma treatment (TSPT). The first step of this method includes: oxygen plasma pretreatment of the PDMS films, immersion in HEMA/AAc mixtures, removal from the mixtures, and drying. The second step was carried out by plasma copolymerization of preadsorbed reactive monomers on the surfaces of dried pretreated films. The effects of pretreatment and polymerization time length, monomer concentration, and ratio on peroxide formation and graft amount were studied. The films were characterized by attenuated total reflection Furrier transformer infrared (ATR‐FTIR) spectroscopy, scanning electron microscopy (SEM), atomic force microscopy (AFM), zeta potential, surface tension, and water contact angle measurements. The ATR‐FTIR spectrum of the modified film after alkaline treatment showed the two new characteristic bands of PHEMA and PAAc. Both increase the polar part of surface tension (γp) after grafting and the evaluation of surface charge at pH 1.8, 7, and 12 confirmed the presence of polar groups on the surface of grafted films with a mixture of HEMA/AAc. Morphological studies using both AFM and SEM evaluation illustrated various amounts of grafted copolymer on the surface of PDMS films. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007
Morphology, thermal, and mechanical properties of acrylonitrile–butadiene–styrene/carbon black composites
Authors: Shenavar A. , Abbasi F.
Published: April 2007

Acrylonitrile–butadiene–styrene (ABS) polymers are susceptible to degradation that increases the yellowness of the polymer, distorts the surface glossy, and affects the mechanical properties. One way to protect ABS against degradation is the addition of carbon black (CB) that can act as a stabilizer. In this work, CB was dispersed in ABS through melt‐compounding. Electron microscopy was used to study the morphology of the filled‐ and unfilled‐ABS, and revealed that the CB particles/aggregates were distributed within the styrene–acrylonitrile (SAN) phase and around the PB phase. The results of the Fourier transform infrared spectroscopy showed that upon processing of ABS, crosslinking in the polybutadiene (PB) phase was the governing degradation mechanism. Increasing the CB content resulted in increasing the heat stability of the ABS/CB compounds, which was confirmed by thermogravimetric analysis. The DTA results showed that the PB degradation peak occurring at about 395°C was disappeared by addition of CB. Impact strength test was performed to study the effect of CB on the toughness of ABS. Impact strength was reduced with increasing CB loading. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007
Production and characterization of polypropylene fiber upon addition of selective peroxide during melt spinning and comparison with conventional polypropylene fibers
Authors: Kalantari Bahareh , Semnani Rahbar Ruhollah , Mojtahedi M. R. M. , Mousavi Shoushtari S. A. , Khosroshahi Ali
Published: April 2007

In the present work, effect of selective peroxide on reactor grade polypropylene (PP) (known as V30S) during melt spinning process on the physical and thermal properties of as‐spun resultant multifilament yarn was studied. Attempts have also been made to compare this yarn sample with other fiber samples produced from reactor and controlled rheology grades polypropylene. The results show that the multifilament yarn spun from V30S/Peroxide sample shows higher birefringence and tensile strength and also lower modulus, elongation at break, and shrinkage compared with that of spun from pure V30S granule. Density and thermal behavior studies show low variations compared with original sample. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007
Organic/inorganic hybrid of polyaniline/BaTiO3 composites and their electrorheological and dielectric characteristics
Authors: Fei Fang Fei , Hye Kim Ji , Jin Choi Hyoung , Seo Yongsok
Published: April 2007

Barium titanate (BaTiO3) inorganic particles which possess large electronic resistance and excellent dielectric properties were employed to synthesize conducting polyaniline (PANI)/BaTiO3 composites via an in situ oxidative polymerization, since conducting PANI/inorganic composites have been considered as a superior candidate of electrorheological (ER) fluids because of their physical properties, unique structure, and the combined merits of the two phases. The influence of the fraction of BaTiO3 particles in the as‐synthesized composites on the physical properties (morphology and crystal structure) and the ER behaviors were examined. Yield stress data obtained were analyzed based on the universal yield stress equation as a function of applied electric field and it was found that the universal yield stress equation collapses these data onto a single curve independent of BaTiO3 particle concentration. Their shear stresses under an applied electric field were also found to be fitted well with the Cho–Choi–Jhon model. In addition, the investigated dielectric spectra were found to be useful to interpret the differences in the ER performances for the PANI/BaTiO3 composite based ER fluids. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007
Synthesis and Anti‐HIV‐1 Activity of New MKC‐442 Analogues with an Alkynyl‐Substituted 6‐Benzyl Group*
Authors: Aly Youssef L. , Pedersen Erik B. , La Colla Paolo , Loddo Roberta
Published: April 2007

Synthesis and antiviral activities are reported of a series of 6‐(3‐alkynyl benzyl)‐substituted analogues of MKC‐442 (6‐benzyl‐1‐(ethoxymethyl)‐5‐isopropyluracil), a highly potent agent against HIV. The 3‐alkynyl group is assumed to give a better stacking of the substituted benzyl group to reverse transcriptase (RT) and this was believed to improve antiviral activity against HIV‐1. The bromo derivatives, 5‐alkyl‐6‐(3‐bromo‐benzyl)‐1‐ethoxymethyl derivatives 7a, b and 5‐alkyl‐6‐(3‐bromobenzyl)‐1‐allyloxymethyl derivatives 9a, b, showed activity against HIV on the same level as their corresponding analogues 10a–d with a 3‐trimethylsilylalkynylbenzyl substituent and their desilylated analogues 11a–d. However, they all showed activity against HIV‐1 wild type in the range of more than 10fold lower than the one of MKC‐442. Moderate activity against Y181C and Y181C + K103N mutated strains was also observed and, in some cases, they were marginally better than those found for MKC‐442. A few amino‐DABO and S‐DABO analogues were also synthesized but they were found to be inactive against HIV.
On the Tacticity of Polynorbornenes with 5,6‐endo Pendant Groups That Contain Substituted Aryl Chromophores
Authors: Lin Wei‐Yu , Wang Hsian‐Wen , Liu Zhi‐Chang , Xu Jun , Chen Chih‐Wei , Yang Yun‐Chin , Huang Shou‐Ling , Yang Hsiao‐Ching , Luh Tien‐Yau
Published: April 2007

Two dimers and a series of polymers with 5,6‐endo pendant aryl groups that contain different substituents at the para positions were synthesized. The conformation and stereochemistry of the dimers and polymers were determined by nonlinear optical analysis (EFISH) as well as UV/Vis and 13C NMR spectroscopy. The chemical shifts of C7 for the polymers appeared as two peaks in the 13C NMR spectra when the substituents are electron‐withdrawing groups. The percentage decrease in the relative extinction coefficient of the polymers, εd, was linearly related to the Hammett constant σ. Polynorbornenes with electron‐withdrawing substituents may adopt isotactic stereochemistry with all pendant groups aligned in one direction. The nature of the interactions between neighboring chromophores may be one of the most important factors in directing the stereoregularity and conformation of these polymers. The corresponding polymers derived from the exo isomers appeared to be less stereoregular.
Modeling the Short‐, Middle‐ and Long‐Term Viral Load Responses for Comparing Estimated Dynamic Parameters
Authors: Huang Yangxin
Published: April 2007

A virologic marker, the number of HIV RNA copies or viral load, is currently used to evaluate antiviral therapies in AIDS clinical trials. This marker can be used to assess the antiviral potency of therapies, but is easily affected by drug exposures, drug resistance and other factors during the long‐term treatment evaluation process. The study of HIV dynamics is one of the most important development in recent AIDS research for understanding the pathogenesis of HIV‐1 infection and antiviral treatment strategies. Although many HIV dynamic models have been proposed by AIDS researchers in the last decade, they have only been used to quantify short‐term viral dynamics and do not correctly describe long‐term virologic responses to antiretroviral treatment. In other words, these simple viral dynamic models can only be used to fit short‐term viral load data for estimating dynamic parameters. In this paper, a mechanism‐based differential equation models is introduced for characterizing the long‐term viral dynamics with antiretroviral therapy. We applied this model to fit different segments of the viral load trajectory data from a simulation experiment and an AIDS clinical trial study, and found that the estimates of dynamic parameters from our modeling approach are very consistent. We may conclude that our model can not only characterize long‐term viral dynamics, but can also quantify short‐ and middle‐term viral dynamics. It suggests that if there are enough data in the early stage of the treatment, the results from our modeling based on short‐term information can be used to capture the performance of long‐term care with HIV‐1 infected patients. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Ultrahigh‐Throughput Screening to Identify E. coli Cells Expressing Functionally Active Enzymes on their Surface
Authors: Becker Stefan , Michalczyk Anja , Wilhelm Susanne , Jaeger Karl‐Erich , Kolmar Harald
Published: April 2007

We show here that E. coli bacteria that display esterases or lipases on their cell surface together with horseradish peroxidase (HRP) are capable of hydrolysing carboxylic acid esters of biotin tyramide. The tyramide radicals generated by the coupled lipase–peroxidase reaction were short‐lived and therefore became covalently attached to reactive tyrosine residues that were located in close vicinity on the surface of a bacterial cell that displayed lipase activity. Up to 120 000 biotinylated tyramide derivatives could be covalently coupled through HRP activation to the surface of a single living E. coli cell. Differences in cellular esterase activity were found to correlate with the amount of biotin tyramide deposited on the cell surface. Selective biotin tyramide labelling of cells that had lipase activity allowed their isolation by magnetic cell sorting from a 1:106 mixture of control cells. This strategy of covalently attaching a biotin label to esterase‐proficient bacteria might open new avenues to ultrahigh‐throughput screening of enzyme libraries for hydrolytic enzymes with enhanced activities or enantioselectivities.
Factorial analysis and psychometric properties of the revised Valencia scale of attitudes and beliefs towards hypnosis‐client version
Authors: Carvalho Claudia , Capafons Antonio , Kirsch Irving , Espejo Begona , Mazzoni Giuliana , Leal Isabel
Published: April 2007

Psychometric properties and factorial structure of the Revised Valencia Scale of Attitudes and Beliefs toward Hypnosis – Client Version using a Portuguese sample are presented. Exploratory factor analysis on a Portuguese population of undergraduate college students (N = 444) yielded 8 factors: ‘Interest/Liking’, ‘Memory/Magic’, ‘Help’, ‘Control’, ‘Cooperation’, ‘Marginal’, ‘Fear’ and ‘Automaton’. The overall 8‐factor structure is similar to the one found in the therapist version of the scale, and as in the therapist version, each factor of the client version showed good internal consistency and reliability. Differences among participants that had and had not experienced hypnosis previously were also assessed. The results indicated that participants with prior experience of hypnosis scored higher on factors indicating positive attitudes and accurate beliefs (‘Interest/Liking’, ‘Help’, ‘Control’ and ‘Cooperation’), whereas participants that had not experienced hypnosis scored higher in factors indicating misconceptions about hypnosis (‘Memory/Magic’, ‘Fear’, ‘Marginal’ and ‘Automaton’). These results indicate that the scale is sensitive to changes in attitudes and beliefs toward hypnosis brought about by the experience of hypnosis in a scientific context. Copyright © 2007 British Society of Experimental & Clinical Hypnosis. Published by John Wiley & Sons, Ltd.
Pharmaceutical Strategy and Innovation: An Academics Perspective
Authors: Baxendale Ian R. , Hayward John J. , Ley Steven V. , Tranmer Geoffrey K.
Published: April 2007

The pharmaceutical industry is under increasing pressure on many fronts, from investors requiring larger returns to consumer groups and health authorities demanding cheaper and safer drugs. It is also feeling additional pressure from the infringement upon its profit margins by generic drug producers. Many companies are aggressively pursuing outsourcing contracts in an attempt to counter many of the financial pressures and streamline their operations. At the same time, the productivity of the pharmaceutical industry at its science base is being questioned in terms of the number of products and the timeframes required for each company to deliver them to market. This has generated uncertainties regarding the current corporate strategies that have been adopted and the levels of innovation being demonstrated. In this essay we discuss these topics in the context of the global pharmaceutical market, investigating the basis for many of these issues and highlighting the hurdles the industry needs to overcome, especially as they relate to the chemical sciences.
Pilot study of regional, hepatic intra‐arterial paclitaxel in patients with breast carcinoma metastatic to the liver
Authors: Camacho Luis H. , Kurzrock Razelle , Cheung Alex , Barber Diane F. , Gupta Sanjay , Madoff David C. , Wallace Michael J. , Kim E. Edmund , Curley Steven A. , Hortobagyi Gabriel N. , Mavligit Giora
Published: April 2007

BACKGROUND.

Approximately 25% of patients with metastatic breast carcinoma develop hepatic involvement during the course of their disease that further affects their survival. Systemic paclitaxel is safe and has demonstrated good antitumor activity against breast carcinoma. The objective of this prospective study was to determine the safety and antitumor activity of hepatic intra‐arterial paclitaxel therapy.

METHODS.

Ten patients with breast carcinoma and dominant liver metastases received monthly, inpatient, 24‐hour, continuous hepatic infusions of paclitaxel at 200 mg/m2 through an intra‐arterial catheter, which was placed using a percutaneous transfemoral approach.

RESULTS.

The mean patient age at the time of treatment was 51 years. Fifty‐six courses of paclitaxel were delivered. The most common treatment‐related toxicities were leukopenia, fatigue, nausea, and vomiting. No procedure‐related complications were observed. Three patients (30%) attained partial responses that lasted for 6 months, 7 months, and 48 months; and 4 other patients had stable disease for 5 months to 9 months. One patient underwent liver resection after receiving hepatic arterial infusions of paclitaxel and remained disease free for 48 months. Eight patients had received prior systemic taxane therapy alone or with other cytotoxic agents. However, no association between previous taxane exposure and the efficacy of the current regimen was established.

CONCLUSIONS.

Hepatic intra‐arterial therapy with paclitaxel at the dose level and on the schedule used in this study was safe and well tolerated and had reasonable antitumor activity against breast carcinoma involving the liver. Previous taxane exposure did not hamper the potential benefit of this approach. This regimen alone or in combination with targeted therapies deserves further investigation in patients with dominant liver metastases from breast carcinoma. Cancer 2007. © 2007 American Cancer Society.
Dehydration and Dehydrogenation of Alcohols with Mononuclear Cationic Vanadium Oxides in the Gas Phase and Energetics of VOnH0/+ (n = 2, 3)
Authors: Engeser Marianne , Schröder Detlef , Schwarz Helmut
Published: April 2007

The ion/molecule reactions of selected alcohols with the vanadium oxide cations VO+ and VO2+ are studied by Fourier‐transform ion‐cyclotron resonance (FT‐ICR) mass spectrometry. Dehydrogenation is the dominating reaction pathway for methanol and allyl alcohols. With larger or less unsaturated alcohols, dehydration and carbocation formations prevail. While the valence in VO+ remains unchanged during alcohol dehydrogenation, VO2+ is reduced to VIII. Thermochemical data for VO2H0/+, VO3H and VO3H2+ are derived by means of ICR bracketing. The experimental results are further complemented by ab initio calculations using density functional theory. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Surfactant‐coated single‐walled carbon nanotubes as a novel pseudostationary phase in capillary EKC
Authors: Suárez Beatriz , Simonet Bartolomé M. , Cárdenas Soledad , Valcárcel Miguel
Published: April 2007

The analytical potential of the use of surfactant‐coated single‐walled carbon nanotubes (SC‐SWNTs) as pseudostationary phase in CE is described. The pseudostationary phase shows an efficient alternative in enhancing electrochromatographic resolution of compounds which are capable of interacting with a nanotube surface, such as aromatic compounds. In general, the resolution is enhanced by increasing nanotube concentration in the buffer but the maximum amount of SWNTs that can be added to background electrolyte was found limited by compatibility with the UV/visible detection. As an alternative, a low‐extension partial filling was used, consisting of the introduction into the capillary of concentrated SC‐SWNT, just before the sample, with a plug length similar to the sample one. This has been showed as a reliable procedure in increasing resolution and sensitivity by sweeping phenomena. Finally, the potential of SC‐SWNTs to perform chiral separations is discussed.
Sample stacking for the analysis of catechins by microemulsion EKC
Authors: Huang Hsi‐Ya , Huang I.‐Yun , Liang Hsin‐hui , Lee Szetsen
Published: April 2007

In this study, an on‐line concentration method, ASEI (anion‐selective exhaustive injection)‐sweeping technology which was coupled with microemulsion EKC (MEEKC), was used to analyze and detect six catechins ((−)‐epicatechin, (+)‐catechin, (−)‐epigallocatechin gallate, (−)‐epicatechin gallate, (−)‐epigallocatechin, and (−)‐gallocatechin). In addition to the effects of the buffer pH and electrolyte concentration on stacking, the compositions of microemulsion (types of oil phase, and types and levels of cosurfactant) also dominated the stacking effect of catechins. In MEEKC, the effect of the type of oil in microemulsion on separation mechanism is often unclear. This study had demonstrated that the oil type in microemulsion indeed altered the affinity of oil droplets with analytes. Finally, this proposed ASEI‐sweeping MEEKC method was able to detect trace level of catechins in food products that was not previously possible by a normal MEEKC method.
Electrokinetic partial filling technique as a powerful tool for enantiomeric separation of DL‐lactic acid by CE with contactless conductivity detection
Authors: Maier Vítězslav , Petr Jan , Knob Radim , Horáková Jana , Ševčík Juraj
Published: April 2007

A modified partial filling method for chiral separation of DL‐lactic acid as the model chiral compound with vancomycin chloride as the chiral selector was developed by CE with contactless conductivity detection. Electrokinetic partial filling technique (EK‐PFT) was used as an alternative method to the conventional hydrodynamic partial filling method. EK‐PFT, in contrast to the hydrodynamic partial filling technique, allowed the removal of the chloride counterions from the chiral selector which otherwise led to poor sensitivity in conductivity detection. The baseline separation of DL‐lactic acid as the model analyte was achieved in 5 min in a polyacrylamide‐coated capillary. The best resolution was achieved by electrokinetic partial filling of vancomycin cations from the injection solution containing 5 mmol/L oxalate L‐histidinium at pH 4.5 with 10 mmol/L vancomycin chloride. Computer simulation was used to explain the observed phenomena in the boundary between the inject vial and the capillary during the EK‐PFT of vancomycin cations.
Major events of Paleogene mammal radiation in China
Authors: Yuanqing Wang , Jin Meng , Xijun Ni , Chuankui Li
Published: April 2007

On the basis of mammalian biostratigraphical study, the Paleogene was subdivided into 11 land mammal ages in China: the Paleocene Shanghuan, Nongshanian and Gashatan; the Eocene Lingchan, Arshantan, Irdinmanhan, Sharamurunian, Naduan and Ulangochuan; and the Oligocene Ulantatalian and Tabenbulukian. Biostratigraphical correlation with North American Land Mammal Ages, plus some palaeomagnetic, isotopic and radiometric results, established the indirect connection with the international time scale. Under this biochronological framework, the compositional change of mammalian faunas and the evolution of major groups are discussed. Three stages are recognized in the Paleogene mammalian radiation: (1) the Paleocene flourishing of archaic groups, (2) the Eocene rising and development of modern major groups and (3) the Oligocene faunal reorganization. During the Paleocene, the mammalian radiation was dominated by the archaic groups and the faunas showed apparent endemism. The radiation was characterized by faunal turnovers due to the flourishing of different families in archaic groups. During this period, ancestral forms of modern glires emerged and the first Rodentiaformes appeared in the late Late Paleocene. Such faunal changes corresponded to the successive rise of temperature after the transition from the Mesozoic to the Cenozoic. The Initial Eocene Thermal Maximum resulted in a significant decrease of the archaic groups and the faunal composition became more similar to that of modern ones. At the beginning of the Eocene, Artiodactyla and Euprimates appeared and Rodentia and Perissodactyla began to differentiate. During the Eocene, Mixodontia, Arctostylopidae, Dinocerata, Pantodonta, Tillodontia and Creodonta disappeared in succession. Perissodactyla became the dominant group in the faunas. The faunal turnovers were characterized by the alteration of dominant families due to the appearance, differentiation and flourishing of families in modern orders. The severe cooling events at the Eocene–Oligocene transition resulted in the development of open grassland, that further contributed to the great mammalian faunal turnover. The perissodactyl‐dominant Eocene faunas were replaced by the rodent/lagomorph‐dominant Oligocene faunas. The appearance and radiation of hypsodont mammal groups characterized the mammalian evolution in the Oligocene. Copyright © 2007 John Wiley & Sons, Ltd.
Advantages of using glycolic acid as a retardant in a brushite forming cement
Authors: Mariño Faleh Tamimi , Torres Jesús , Hamdan Mohammad , Rodríguez Carmen Rueda , Cabarcos Enrique López
Published: April 2007

In this study we have compared the effect of using acetic, glycolic, and citric acids on the brushite cement setting reaction and the properties of the resultant cement. The cement solid phase was made by mixing β‐tricalcium phosphate (β‐TCP), monocalcium dihydrogen phosphate anhydrate (MCPA), and sodium pyrophosphate, whereas the cement liquid phase consisted of aqueous solutions of carboxy acids at concentrations ranging from 0.5 to 3.5M. Cements were prepared by mixing the solid phase with the liquid phase to form a workable paste. The cement setting time was longer for glycolic and citric acids. The best mechanical properties in dry environments were obtained using glycolic and citric acid liquid phases. In a wet environment at 37°C, the cement set with glycolic acid was the strongest one. Brushite cement diametral tensile strength seems to be affected by the calcium‐carboxyl phase produced in the setting reaction. The acceptable setting time and mechanical properties of cements set in glycolic acid solutions are attributed to the additional hydrophilic groups in the carboxylic acid and the low solubility in water of the calcium salt produced in the reaction. Moreover, at high concentrations, carboxylic acids add chemically to the cement matrix becoming reactants themselves. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2007
Repair of the dura mater with processed collagen devices
Authors: Zerris Vasilios A. , James Kenneth S. , Roberts Julie B. , Bell Eugene , Heilman Carl B.
Published: April 2007

Background: We evaluated in a canine duraplasty model how specific differences in device physicomechanical properties, porosity, and crosslinking influenced the biological performance of three processed collagen dural substitutes. Methods: Three collagen dural substitutes were studied: Dura‐Guard, DuraGen, and Durepair. The initial strength, stiffness, and suture retention force were measured using standard mechanical test methods. The relative pore sizes of each device were assessed with a scanning electron microscope. Differential scanning calorimetry was used to measure their respective collagen denaturation temperatures. The biologic response and performance of the materials were evaluated via an acute (1 month) and long‐term (3 and 6 months) canine bilateral duraplasty study. Results: The mechanical properties of Dura‐Guard and Durepair were similar to native dura. We could not quantify the mechanical properties of DuraGen because of its fragile nature. The denaturation temperature of DuraGen and Dura‐Guard differed significantly from that reported for native collagens. The denaturation temperature of Durepair was comparable with the values reported for native collagens. All three materials were tolerated well by the animals. DuraGen did not maintain its structural integrity beyond 1 month. Dura‐Guard and Durepair persisted for 6 months. Durepair was populated by fibroblasts and blood vessels, whereas Dura‐Guard was not. Conclusions: The three dural substitutes tested were found to be safe and effective in healing surgically created defects in the dura mater. Although each of these dura substitutes are composed of collagen, differences in the collagen source and processing influenced device physicomechanical properties, porosity, and the nativity of the collagen polymer. These measured differences influenced device intraoperative handling and installation as well as the post‐operative biological response, where differences in device resorption, cell penetration, vascularization, and collagen remodeling were observed. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2007
Acrylic injectable and self‐curing formulations for the local release of bisphosphonates in bone tissue
Authors: Rodríguez‐Lorenzo L. M. , Fernández M. , Parra J. , Vázquez B. , López‐Bravo A. , Román J. San
Published: April 2007

Two bisphosphonates (BPs), namely 1‐hydroxy‐2‐[4‐aminophenyl]ethane‐1,1‐diphosphonic acid (APBP) and 1‐hydroxy‐2‐[3‐indolyl]ethane‐1,1‐diphosphonic acid (IBP), have been synthesized and incorporated to acrylic injectable and self‐curing formulations. Alendronic acid monosodium trihydrated salt (ALN) containing cement was formulated as control. These systems have potential applications in low density hard tissues affected by ailments characterized by a high osteoclastic resorption, i.e. osteoporosis and osteolysis. Values of curing parameters of APBP and IBP were acceptable to obtain pastes with enough fluency to be injected through a biopsy needle into the bone cavity. Working times ranged between 8 and 15 min and maximum temperature was around 50°C. Cured systems stored for a month in synthetic body fluid had compressive strengths between 90 and 96 MPa and modulus between 1.2 and 1.3 GPa, which suggest mechanical stabilization after setting and in the short time. BPs were released in PBS at an initial rate depending on the corresponding chemical structure in the order ALN > APBP > IBP to give final concentrations in PBS of 2.21, 0.44, and 0.19 mol/mL for ALN, APBP, and IBP, respectively. Cytotoxicities of bisphosphonates were evaluated, IC50 values being in the order APBP > ALN > IBP. Absence of cytotoxicity coming from leachables of the cured systems was observed in all cases independently of the BP. An improved cell growth and proliferation for the systems loaded with APBP and IBP compared with that loaded with ALN was observed, as assessed by measuring cell adhesion and proliferation, and total DNA content. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2007
Effects of different magnitudes of cyclic stretch on Na+‐K+‐ATPase in skeletal muscle cells in vitro
Authors: Yuan Xiao , Lin Zhu , Luo Songjiao , Ji Guoping , Yuan Changqing , Wu Yong
Published: April 2007

The Na+‐K+‐ATPase, which plays a major role in modulation of skeletal muscle excitability and contractility, is one of the marker enzymes that senses the mechanical strain and adapts to the stimuli. Although many papers had been published on the effects of mechanical stress on Na+‐K+‐ATPase in aortic smooth muscle cells, little was known about the effects of different magnitudes of mechanical stretch on Na+‐K+‐ATPase in skeletal muscle cells. In the present study, we determined the effect of different magnitudes(6%, 12%, or 25% elongation) of cyclic stretch on the activity of the Na+‐K+‐ATPase and investigated possible mechanisms that might be involved in the action of stretch.The results showed the application of different magnitudes of cyclic stretch induced a magnitude‐dependent increase of Na+‐K+‐ATPase activity in cultured skeletal muscle cells. Furthermore, inhibition of ionic fluxes through SACs prevented the action of stretch on Na+‐K+‐ATPase activity. The stretch‐induced increase in Na+‐K+‐ATPase activity was not blocked by Actinomycin D. No significant changes in mRNA and total cell protein levels of Na+‐K+‐ATPase were detected after stretched continuious for 24 h. However, cyclic stretch increased cell surface expression of Na+‐K+‐ATPase α1‐ and α2‐subunit proteins by 1.3‐ and 1.75‐fold, respectively, and the increases in Na+‐K+‐ATPase activity and cell surface expression were abolished by LY‐294002. These data indicated that cyclic stretch induced a “magnitude‐dependent” increase of Na+‐K+‐ATPase activity in cultured skeletal muscle cells in vitro. The upregulation involved translocation of Na+‐K+‐ATPase α1‐ and α2‐subunits to plasma membrane, not increased gene transcription. These results suggested a novel nontranscriptional mechanism for regulation of Na+‐K+‐ATPase in skeletal muscle cells by cyclic stretch. J. Cell. Physiol. 212: 509–518, 2007. © 2007 Wiley‐Liss, Inc.
Estrogen receptor alpha (ERα) and insulin‐like growth factor I receptor (IGF‐IR) cross‐talk in the gonadotropic αT3‐1 cell line
Authors: Eertmans Frank , Dhooge Willem , De Wever Olivier , Bracke Marc , Comhaire Frank , Kaufman Jean‐Marc
Published: April 2007

In reproductive tissues such as the breast and the uterus, cell proliferation and differentiation is strongly regulated by complex interactions between estrogen receptor α (ERα) and growth factor receptors. In the present study, we investigated the potential occurrence of such cross‐talk in the murine, gonadotropic αT3‐1 cell line, which expresses ERα and the IGF‐I receptor (IGF‐IR). Under estrogen‐free conditions, basal cell proliferation and ER‐mediated gene transcription was strongly inhibited by the selective estrogen receptor modulator (SERM) 4‐hydroxy‐tamoxifen (4‐OH‐Tam) and by the pure anti‐estrogen ICI 182,780 (ICI). These effects can be reversed by either 17‐β‐estradiol (E2) or insulin‐like growth factor I (IGF‐I), both exerting modest mitogenic effects in the αT3‐1 cell line. Furthermore, IGF‐I enhanced both basal and E2‐induced ER‐driven gene transcription. This may be explained, at least in part, by enhanced phosphorylation of ERα at serine 118, a prerequisite for the transactivation capacity of the receptor. Finally, the IGF‐I‐induced response on cell growth and ER‐mediated transactivation can be inhibited with either ICI or 4‐OH‐Tam. In conclusion, our data indicate IGF‐IR and ER interactions in the αT3‐1 cell line, an in vitro model for the pituitary gonadotrophs, hereby suggesting a role of IGF‐I in the regulation of gonadotropin synthesis and secretion. J. Cell. Physiol. 212:583–590, 2007. © 2007 Wiley‐Liss, Inc.
AKT and MAPK signaling in KGF‐treated and UVB‐exposed human epidermal cells
Authors: Lotti Lavinia Vittoria , Rotolo Sabrina , Francescangeli Federica , Frati Luigi , Torrisi Maria Rosaria , Marchese Cinzia
Published: April 2007

Regulation of proliferation and differentiation in keratinocyte is a complex and dynamic process that involves activation of multiple signaling pathways triggered by different growth factors. Keratinocyte growth factor (KGF) is not only a potent mitogen, but differently from other growth factors, is a potent inducer of differentiation. The MAP kinase and AKT pathways are involved in proliferation and differentiation of many cell types including keratinocytes. We investigated here the role of KGF in modulating AKT and MAPK activity during differentiation of human keratinocytes. Our results show that the mechanisms of action of KGF are dose‐dependent and that a sustained activation of the MAPK signaling cascade causes a negative regulation of AKT. We also demostrated increasing expression of KGFR substrates, such as PAK4 during keratinocyte differentiation parallel to the receptor upregulation. J. Cell. Physiol. 212:633–642, 2007. © 2007 Wiley‐Liss, Inc.
The immunomodulatory protein SV‐IV protects serum‐deprived cells against apoptosis but not against G0/G1 arrest: Possible implications for the survival of implanting embryo
Authors: Morelli Francesco , Peluso Gianfranco , Petillo Orsolina , Giannattasio Angela , Filosa Silvana , Motta Chiara M. , Tammaro Stefania , Zatterale Adriana , Calzone Rita , Budillon Alfredo , Cartenì Maria , de Maria Salvatore , Costanza Maria R. , Nigro Antonella , Petrazzuolo Marcella , Buommino Elisabetta , Rizzo Maria , Capasso Giovanni , Baiano Salvatore , Moscatiello Francesco , Ravagnan Gianpietro , Fuggetta Maria P. , Tajana Gianfranco , Stiuso Paola , Metafora Bianca M. , Metafora Vittoria , Metafora Salvatore
Published: April 2007

Serum deprivation induced in human lymphoblastoid Raji cells oxidative stress‐associated apoptotic death and G0/G1 cell cycle arrest. Addition into culture medium of the immunomodulatory protein Seminal vesicle protein 4 (SV‐IV) protected these cells against apoptosis but not against cycle arrest. The antiapoptotic activity was related to: (1) decrease of endocellular reactive Oxygen species (ROS) (2) increase of mRNAs encoding anti‐oxidant enzymes (catalase, G6PD) and antiapoptotic proteins (survivin, cox‐1, Hsp70, c‐Fos); (3) decrease of mRNAs encoding proapoptotic proteins (c‐myc, Bax, caspase‐3, Apaf‐1). The biochemical changes underlaying these effects were probably induced by a protein tyrosine kinase (PTK) activity triggered by the binding of SV‐IV to its putative plasma membrane receptors. The ineffectiveness of SV‐IV to abrogate the cycle arrest was accounted for by its downregulating effects on D1,3/E G1‐cyclins and CdK2/4 gene expression, ppRb/pRb ratio, and intracellular ROS concentration. In conclusion, these experiments: (1) prove that SV‐IV acts as a cell survival factor; (2) suggest the involvement of a PTK in SV‐IV signaling; (3) point to cell cycle‐linked enzyme inhibition as responsible for cycle arrest; (4) provide a model to dissect the cycle arrest and apoptosis induced by serum withdrawal; (5) imply a possible role of SV‐IV in the survival of hemiallogenic implanting embryos. J. Cell. Physiol. 212:610–625, 2007. © 2007 Wiley‐Liss, Inc.
Prostate carcinoma cells selected by long‐term exposure to reduced oxygen tension show remarkable biochemical plasticity via modulation of superoxide, HIF‐1α levels, and energy metabolism
Authors: Bourdeau‐Heller Jeanne , Oberley Terry D.
Published: April 2007

Cancer cells are able to tolerate levels of O2 that are damaging or lethal to normal cells; we hypothesize that this tolerance is the result of biochemical plasticity which maintains cellular homeostasis of both energy levels and oxidation state. In order to examine this hypothesis, we used different O2 levels as a selective agent during long‐term culture of DU145 prostate cancer cells to develop three isogenic cell lines that grow in normoxic (4%), hyperoxic (21%), or hypoxic (1%) O2 conditions. Growth characteristics and O2 consumption differed significantly between these cell lines without changes in ATP levels or altered sensitivity to 2‐deoxy‐D‐glucose, an inhibitor of glycolysis. O2 consumption was significantly higher in the hyperoxic line as was the level of endogenous superoxide. The hypoxic cell line regulated the chemical gradient of the proton motive force (PMF) independent of the electrical component without O2‐dependent changes in Hif‐1α levels. In contrast, the normoxic line regulated Hif‐1α without tight regulation of the chemical component of the PMF noted in the hypoxic cell line. From these studies, we conclude that selection of prostate cancer cells by long‐term exposure to low ambient levels of O2 resulted in cells with unique biochemical properties in which energy metabolism, reactive oxygen species (ROS), and HIF‐1α levels are modulated to allow cell survival and growth. Thus, cancer cells exhibit remarkable biochemical plasticity in response to various O2 levels. J. Cell. Physiol. 212:744–752, 2007. © 2007 Wiley‐Liss, Inc.
Ceramide inhibits LPS‐induced production of IL‐5, IL‐10, and IL‐13 from mast cells
Authors: Chiba Norika , Masuda Akio , Yoshikai Yasunobu , Matsuguchi Tetsuya
Published: April 2007

Mast cells are central regulators of allergic inflammation through production of various chemical mediators and cytokines. Bacterial infection occasionally worsens allergic inflammation. Although the exact mechanism of this phenomenon remains unclear, we have previously reported that LPS stimulates mast cells to produce not only pro‐inflammatory cytokines, such as IL‐6 and TNF‐α, but also Th2‐type cytokines, such as IL‐5 and IL‐13, and a regulatory cytokine, IL‐10. In the present study, we have studied the effect of ceramide on LPS‐mediated cytokine production from mast cells, as ceramide modulates various cellular functions in many cell types. Administration of cell‐permeable C8 ceramide reduced production of IL‐5, IL‐10, and IL‐13 from LPS‐stimulated mouse bone marrow‐derived mast cells (BMMCs) apparently through transcriptional inhibition, but did not affect IL‐6 or TNF‐α production. Consistently, LPS‐stimulated production of IL‐5, IL‐10, and IL‐13 from BMMCs is significantly enhanced in the presence of fumonisin B1, a de novo ceramide synthesis inhibitor. Interestingly, the same C8 ceramide treatment showed opposite effects on cytokine production from LPS‐stimulated macrophages, reducing IL‐6 and TNF‐α while not affecting IL‐10 production. C8 ceramide pretreatment significantly reduced LPS‐induced Akt phosphorylation in BMMCs, but not in macrophages. Furthermore, pretreatment of BMMCs by wortmannin, a specific inhibitor of PI3 kinase, inhibited LPS‐stimulated expression of IL‐5, IL‐10, and IL‐13, but not that of TNF‐α or IL‐6. Thus, ceramide appeared to down‐regulate LPS‐stimulated production of IL‐5, IL‐10, and IL‐13 from mast cells by inhibiting PI3 kinase‐Akt pathway in a cell type‐specific manner. J. Cell. Physiol. 213: 126–136, 2007. © 2007 Wiley‐Liss, Inc.
Fundamentals of viviparity: Comparison of seasonal changes in the uterine epithelium of oviparous and viviparous Lerista bougainvillii (Squamata: Scincidae)
Authors: Adams Susan M. , Biazik Joanna , Stewart Rebecca L. , Murphy Christopher R. , Thompson Michael B.
Published: April 2007

Distinct differences in epithelial response between oviparous and viviparous species of skinks led us to investigate morphological differences in the uterus of a species that exhibits bi‐modal reproduction and that may indicate specialities for the different requirements of viviparity and oviparity. The uteri of females from oviparous and viviparous populations of the Australian scincid lizard, Lerista bougainvillii, are described in detail to determine whether the occurrence of uterodomes and the plasma membrane transformation, found in other viviparous species but not oviparous species, are indeed features characteristic of viviparity. Oviductal tissue was dissected at three different stages of reproduction from lizards from both populations: 1) vitellogenic, 2) gravid or pregnant, and 3) non‐reproductive or quiescent. Tissue was observed using both scanning and transmission electron microscopy. Lerista bougainvillii has a simple placental morphology with simple squamous epithelium. In contrast to mammals and other viviparous skinks, L. bougainvillii does not undergo a plasma membrane transformation, but early signs of placentation in viviparous individuals are indicated by changes in the uterine surface that occur largely after embryonic stage 30. There are no obvious cellular differences between the uteri of oviparous and viviparous L. bougainvillii at the non‐reproductive and vitellogenic phase of the reproductive cycle but throughout gestation/gravidity, the cellular differences that could be related to the changing functional requirements with the retention of the viviparous embryo, became apparent. A plasma membrane transformation with ensuing uterodome formation does not occur, which suggests that these more sophisticated changes are a feature of advanced placental development in reptiles. J. Morphol., 2007. © 2007 Wiley‐Liss, Inc.
Morphology and mechanics of the teeth and jaws of white‐spotted bamboo sharks (Chiloscyllium plagiosum)
Authors: Ramsay Jason B. , Wilga Cheryl D.
Published: April 2007

The teeth of white‐spotted bamboo sharks (Chiloscyllium plagiosum) are used to clutch soft‐bodied prey and crush hard prey; however, the dual function is not evident from tooth morphology alone. Teeth exhibit characteristics that are in agreement with a clutching‐type tooth morphology that is well suited for grasping and holding soft‐bodied prey, but not for crushing hard prey. The dual role of this single tooth morphology is facilitated by features of the dental ligament and jaw joint. Tooth attachment is flexible and elastic, allowing movement in both sagittal and frontal planes. During prey capture spike‐like tooth cusps pierce the flesh of soft prey, thereby preventing escape. When processing prey harder than the teeth can pierce the teeth passively depress, rotating inward towards the oral cavity such that the broader labial faces of the teeth are nearly parallel to the surface of the jaws and form a crushing surface. Movement into the depressed position increases the tooth surface area contacting prey and decreases the total stress applied to the tooth, thereby decreasing the risk of structural failure. This action is aided by a jaw joint that is ventrally offset from the occlusal planes of the jaws. The offset joint position allows many teeth to contact prey simultaneously and orients force vectors at contact points between the jaws and prey in a manner that shears or rolls prey between the jaws during a bite, thus, aiding in processing while reducing forward slip of hard prey from the mouth. Together the teeth, dental ligament, and jaws form an integrated system that may be beneficial to the feeding ecology of C. plagiosum, allowing for a diet that includes prey of varying hardness and elusiveness. J. Morphol., 2007. © 2007 Wiley‐Liss, Inc.
Smooth muscle‐associated protein 8: Distribution and biological activity in the rat brain
Authors: Brailoiu G. Cristina , Dun Siok L. , Mizuo Keisuke , Brailoiu Eugen , Yang Jun , Chang Jaw Kang , Dun Nae J.
Published: April 2007

With the use of an antiserum directed against the human smooth muscle‐associated protein 8 (SMAP8) fragment SMAP898–138, Western blot and immunohistochemical studies revealed SMAP8 expression in the rat brain. A band with a molecular size of about 45 kDa was detected in tissues from the rat hypothalamus and a weaker band from the cortex. SMAP8 immunoreactivity (irSMAP8) was detected in neurons of the hypothalamic paraventricular, supraoptic, and supraoptic retrochiasmatic nuclei; a few irSMAP8 cells were scattered in the zona incerta as well as the cerebral cortex. Immunoreactive cell processes were detected mostly in the internal layer of the median eminence. Double labeling the hypothalamic sections with SMAP8 and vasopressin (VP) or oxytocin (OT) antiserum revealed that a population of VP‐ and OT‐immunoreactive neurons expressed irSMAP8. The biological activity of SMAP8 in rat central neurons was assessed by the calcium microfluorimetric Fura‐2 method. SMAP8 (100 nM) elevated cytosolic calcium concentrations [Ca2+]i in a population of dissociated and cultured rat hypothalamic neurons; the response was eliminated in Ca2+‐free saline. This is the first evidence of irSMAP8 in a population of VP/OT‐containing hypothalamic neurons in the rat, and the peptide is biologically active in hypothalamic neurons, as evidenced by mobilization of extracellular Ca2+. © 2007 Wiley‐Liss, Inc.