bluuebunny/crossref_metadata_2025_split huggingface dataset:
Trimethylsilyl-substituted Dibenzodehydro[12]annulene Having High Thermal and Chemical Stability
Authors: Setaka Wataru , Kanai Shoko , Kabuto Chizuko , Kira Mitsuo 
Published: November 2006

Abstract
1,4,9,12-Tetrakis(trimethylsilyl)dibenzodehydro[12]annulene (3) was synthesized by the Eglinton coupling reaction in a good yield. In contrast to parent dibenzodehydro[12]annulene, 3 has extremely high thermal and chemical stability, probably due to the steric protection of the annulene ring by bulky trimethylsilyl substituents on benzene.
A Facile Fabrication to Cellulose-based Nanoparticles with Thermo-responsivity and Carboxyl Functional Groups
Authors: Dou Hong-jing , Yang Wei-hai , Sun Kang 
Published: November 2006

Abstract
Cellulose-based nanoparticles having thermo-sensitivity and carboxyl functional groups were fabricated for the first time without using any surfactant and organic solvent. The nanoparticles exhibit rapid and reversible dispersion–aggregation changes in response to narrow range temperature alternation near our body temperature as demonstrated by dynamic light scattering, which may be utilized in biomedical fields.
Treatment of Skeletally Mature Ovariectomized Rhesus Monkeys With PTH(1-84) for 16 Months Increases Bone Formation and Density and Improves Trabecular Architecture and Biomechanical Properties at the Lumbar Spine
Authors: Fox John , Miller Michael A , Newman Michael K , Turner Charles H , Recker Robert R , Smith Susan Y 
Published: November 2006

Abstract
Histomorphometric studies of treatments for osteoporosis in humans are restricted to iliac crest biopsies. We studied the effects of PTH(1-84) treatment at the lumbar spine of skeletally mature ovariectomized rhesus monkeys. PTH increased bone turnover, rapidly normalized BMD, and increased vertebral compressive strength. PTH increased trabecular bone volume primarily by increasing trabecular number by markedly increasing intratrabecular tunneling.
Introduction: Histomorphometric studies of the anabolic properties of PTH(1-84) (PTH) and related peptides in human bone are restricted to iliac crest biopsies. The ovariectomized (OVX) monkey is an accepted model of human postmenopausal bone loss and was used to study the effects of PTH treatment at clinically relevant skeletal sites.
Materials and Methods: Skeletally mature rhesus monkeys were OVX or sham-operated and, after a bone depletion period of 9 months, treated daily for 16 months with PTH (5, 10, or 25 μg/kg). Markers of bone formation (serum osteocalcin) and resorption (urine N-telopeptide [NTX]) and lumbar spine BMD were measured throughout the study. Trabecular architecture and vertebral biomechanical properties were quantified at 16 months.
Results: PTH treatment induced dose-dependent increases in bone turnover but did not increase serum calcium. Osteocalcin was significantly increased above OVX controls by 1 month. NTX was significantly elevated at 1 month with the highest dose, but not until 12 months with the 5 and 10 μg/kg doses. Lumbar spine BMD was 5% lower in OVX than in sham animals when treatment was started. All PTH doses increased BMD rapidly, with sham levels restored by 3–7 months with 10 and 25 μg/kg and by 16 months with 5 μg/kg. PTH treatment increased trabecular bone volume (BV/TV), primarily by increasing trabecular number, and dose-dependently increased bone formation rate (BFR) solely by increasing mineralizing surface. The largest effects on BV/TV and yield load occurred with the 10 μg/kg dose. The highest dose reduced trabecular thickness by markedly increasing intratrabecular tunneling.
Conclusions: PTH treatment of OVX rhesus monkeys increased bone turnover and increased BV/TV, BMD, and strength at the lumbar spine. All PTH doses were safe, but the 10 μg/kg dose was generally optimal, possibly because the highest dose resulted in too marked a stimulation of bone remodeling.
Survival of Largemouth Bass from Populations Infected with Largemouth Bass Virus and Subjected to Simulated Tournament Conditions
Authors: Schramm Harold L. , Davis Jonathan G. 
Published: November 2006

Abstract
Mortality was measured for largemouth bass Micropterus salmoides in simulated tournaments conducted at 26°C to determine whether an easily accomplished live-well management protocol reduced mortality. Treatment fish, which received the live-well management protocol, were held for 8 h in live wells at 23°C with water containing more than 5 mg of dissolved oxygen/L and 0.3% salt (NaCl). Control fish, were confined for 8 h in live wells at 26°C (ambient temperature) with dissolved oxygen fluctuating from 3 to 5 mg/L and no salt, which simulated the live-well management practices used by largemouth bass tournament anglers. Mortality after live-well confinement was 0% for both treatment and control fish, and mortality during the first 24 h after the simulated tournaments was 2.5%. Mortality of fish observed for up to 5 d after the simulated tournaments was high for treatment fish (mean = 75%; SE = 16%) and control fish (mean = 85%; SE = 11%), and we conclude that the treatment conditions did not reduce postrelease mortality. We suggest that the unusually high posttournament mortality was related to largemouth bass virus infections.
Effects of Explosives on Incubating Lake Trout Eggs in the Canadian Arctic
Authors: Faulkner Sean G. , Tonn William M. , Welz Marek , Schmitt Douglas R. 
Published: November 2006

Abstract
Industrial development, including geophysical exploration and mining, has increased use of explosives in and near fish habitat. To protect fish and their incubating eggs, Canadian blasting guidelines contain maximum allowable limits for overpressure and peak particle velocity (PPV). Although many studies have focused on how overpressure causes mortality in fish, no studies have examined the effects of PPVs from explosives on fish eggs. We exposed the eggs of lake trout Salvelinus namaycush to blasts from an open-pit mine at Lac de Gras, Northwest Territories, and measured the effects on egg mortality. Twenty Plexiglas incubators, each containing 50 eggs, were placed in the lake substrate at four sites; blast-monitoring equipment was also positioned at these sites. Three sites were within 220 m of the pit's dike, in a zone where PPVs were predicted to exceed the guidelines. A reference site was located outside of this blast zone 2 km away from the pit. Substrate at one of the blast zone sites was composed of material used in dike construction, whereas other sites were natural spawning shoals. To assess egg mortality during the period of greatest egg sensitivity to physical disturbance, half of the incubators were retrieved after 20 d; the remaining incubators were retrieved at ice-out. After 20 d, mortality at two of the three blast zone sites was lower than reference mortality, whereas mortality at the third site did not differ from the reference level. At ice-out, the single blast zone site with nonnatural substrate had higher mortality (by 10%) than the reference site. Ice-out mortality at the other two blast zone sites was similar to that of the reference site. Given that the largest blast exposure (28.5 mm/s) throughout the incubation period was more than double the current maximum allowable limit but still produced mortality similar to the reference level, we suggest that existing guidelines provide ample protection under these blasting conditions. The margin of this protection, however, remains unknown.
Phytoestrogens regulate transcription and translation of vitamin D receptor in colon cancer cells
Authors: Gilad Liat Abovich , Tirosh Oren , Schwartz Betty 
Published: November 2006

The present study assesses the effects of two isoflavones, genistein and glycitein, and equol – a product of intestinal bacterial metabolism of dietary isoflavones, on vitamin D receptor (VDR) expression in an intestinal HT29 cell line. Genistein and glycitein significantly upregulated the VDR transcription and translation in HT29 cells. The effect of equol was less pronounced.
Treating HT29 cells transfected with a vector containing the VDR promoter next to a luciferase reporter with genistein or glycitein resulted in significant upregulation of VDR promoter activity, in a manner similar to that induced by 17β-estradiol (E2). Again, the effect of equol was less pronounced. VDR luciferase promoter activity was upregulated most by genistein, then by glycitein and least by equol when the VDR promoter was cotransfected with estrogen receptor β.
Reporter gene and chromatin immunoprecipitation (ChIP) assays demonstrated that E2 upregulates AP-1 and Sp-1 sites present on the VDR gene. In contrast, the same assays demonstrated that the Sp-1, but not AP-1, site is induced by the phytoestrogens.
Similar to E2, genistein, glycitein and the isoflavonoid metabolite equol induced higher concentrations of intracellular free calcium, an event that could provide the upstream mechanism(s) induced by E2 and phytoestrogens that initiates the signaling cascade which results in the activation of extracellular signal-regulated kinase (ERK) signaling pathways and modulation of Sp-1 sites of the VDR gene, and culminates in enhanced VDR expression.
Simultaneous Determination of Thiocyanate and Salycilate by a Combined UV‐Spectrophotometric Detection Principal Component Artificial Neural Network
Authors: Karimi Hajir , Ghaedi Mehrorang 
Published: November 2006

AbstractA modified principle component artificial neural network (PC‐ANN) model is developed for simultaneous determination of thiocyanate and salycilate concentration after passing through the bulk of a liquid membrane by tri‐phenyl benzyl phosphonium chloride. All calibration, and test samples data were obtained using UV‐Vis spectrophotometer. In this way, a modified PC‐ANN consisting of three layers of nodes was trained by combination of Bayesian‐Levenberg‐Marquardt as training rule. Sigmoid and liner transfer functions were used in the hidden and output layers respectively to facilitate nonlinear calibration. The model could accurately estimate the concentration of components with acceptable precision and accuracy, for mixtures. The PC‐ANN model exhibits a good ability for the simultaneous determination of the thiocyanate and salycilate in concentration range 0.5 × 10−4mol.l−1up to 5.0 × 10−4mol.l−1with Root Mean square error (2.22% and 2.20%, for thiocyanate and salycilate, respectively) and high correlation coefficients (R2= 0.998 or greater). Results obtained with modified trained PC‐ANN were compared with stepwise linear regression (SMLR) model. Validation of the two models shows a better ability in estimation of the modified PC‐ANN as compared with the SMLR model (MSRE given are 3.12%, 6.31%.).
Municipal sludge degradation kinetic in thermophilic CSTR
Authors: de la Rubia Ángeles , Pérez Montserrat , Sales Diego , Romero Luis I. 
Published: November 2006

AbstractThe performance of a pilot‐scale continuous‐flow stirred‐tank reactor (CSTR) treating municipal sludge under thermophilic conditions has been studied. Two pilot‐scale reactors (CSTR1 (175 L) and CSTR2 (850 L)) were operated at different hydraulic residence times (θ: 40 to 15 days). The anaerobic sludge processes are generally affected by variations in the concentration of substrate (determined as influent volatile solids, VS) and volumetric flow, both of which lead to a modification in biomass concentration and VS removal efficiency. This unsteady‐state situation is mathematically explained in terms of an autocatalytic kinetic model. The general kinetic equation in this model has been applied to experimental data obtained in CSTR1. The fit of the experimental data to the model was used to estimate kinetic parameters and the yield coefficients (μmax, α, YP/S). The estimated parameters were μmax: 0.175d−1, α: 0.358, YP/S: 0.309 m3CH4/kgVS). These parameters were subsequently used to model the substrate utilization rate and the methane generation rate in CSTR2. The model with the estimated parameters was found to provide excellent results, and is satisfactory in describing the concentration of VS and the methane generation rate in an actual digestion plant. © 2006 American Institute of Chemical Engineers AIChE J, 2006
Reaktionen in Mikrofluidiktröpfchen
Authors: Song Helen , Chen Delai L. , Ismagilov Rustem F. 
Published: November 2006

AbstractTröpfchenbasierte Mikrofluidiksysteme bieten in der Chemie und Biologie ausgezeichnete experimentelle Möglichkeiten für die Grundlagenforschung und angewandte Forschung. Sie ermöglichen die Miniaturisierung von Reaktionen, indem Reaktionsvolumina in femto‐ bis mikrolitergroßen Tröpfchen kompartimentiert werden. Die Kompartimentierung in Tröpfchen ermöglicht die schnelle Durchmischung der Reagentien, die zeitliche Steuerung der Reaktionen im Bereich von Millisekunden bis zu Monaten, die Steuerung von Grenzflächeneigenschaften und die Synthese und den Transport von festen Reagentien und Produkten. Mithilfe von tröpfchenbasierten Mikrofluidiksystemen können Anwendungen im Bereich des chemischen und biologischen Screenings, der Proteinkristallisation und der Enzymkinetik verbessert und beschleunigt werden. Darüber hinaus bietet die mögliche Steuerung von Tröpfchen in Mikrofluidikeinheiten Aussichten auf neue wissenschaftliche Methoden und Erkenntnisse.
Luminol chemiluminescence catalysed by colloidal platinum nanoparticles
Authors: Xu Sheng‐Liang , Cui Hua 
Published: November 2006

AbstractPlatinum colloids prepared by the reduction of hexachloroplatinic acid with citrate in the presence of different stabilizers were found to enhance the chemiluminescence (CL) of the luminol–H2O2 system, and the most intensive CL signals were obtained with citrate‐protected Pt colloids synthesized with citrate as both a reductant and a stabilizer. Light emission was intense and reproducible. Transmission electron microscopy and X‐ray photoelectron spectroscopy studies were conducted before and after the CL reaction to investigate the possible CL enhancement mechanism. It is suggested that this CL enhancement is attributed to the catalysis of platinum nanoparticles, which could accelerate the electron‐transfer process and facilitate the CL radical generation in aqueous solution. The effects of Pt colloids prepared by the hydroborate reduction were also investigated. The application of the luminol–H2O2–Pt colloids system was exploited for the determination of compounds such as uric acid, ascorbic acid, phenols and amino acids. Copyright © 2006 John Wiley & Sons, Ltd.
Luminol–hydrogen peroxide chemiluminescence produced by sweet potato peroxidase
Authors: Alpeeva Inna S. , Yu. Sakharov Ivan 
Published: November 2006

AbstractAnionic sweet potato peroxidase (SPP; Ipomoea batatas) was shown to efficiently catalyse luminol oxidation by hydrogen peroxide, forming a long‐term chemiluminescence (CL) signal. Like other anionic plant peroxidases, SPP is able to catalyse this enzymatic reaction efficiently in the absence of any enhancer. Maximum intensity produced in SPP‐catalysed oxidation of luminol was detected at pH 7.8–7.9 to be lower than that characteristic of other peroxidases (8.4–8.6). Varying the concentrations of luminol, hydrogen peroxide and Tris buffer in the reaction medium, we determined favourable conditions for SPP catalysis (100 mmol/L Tris–HCl buffer, pH 7.8, containing 5 mmol/L hydrogen peroxide and 8 mmol/L luminol). The SPP detection limit in luminol oxidation was 1.0 × 10−14 mol/L. High sensitivity in combination with the long‐term CL signal and high stability is indicative of good promise for the application of SPP in CL enzyme immunoassay. Copyright © 2006 John Wiley & Sons, Ltd.
Adsorption, absorption, and biological degradation of ammonia in different biofilter organic media
Authors: Pagans Estela , Font Xavier , Sánchez Antoni 
Published: November 2006

AbstractA tailor‐made apparatus called ammoniometer, which is a batch mode respirometer applied to the study of ammonia biodegradation in biofilter media, has been used to evaluate adsorption, absorption, and biodegradation in five different organic materials (compost, coconut fibre, bark, pruning wastes, and peat) obtained from full‐scale biofilters in operation in several waste treatment plants. The results showed that absorption could be represented by a Henry's law linear equation, with values of the Henry coefficient significantly higher (from 1,866 to 15,320) than that of pure water (1,498). Adsorption data were successfully fitted to Langmuir and Freundlich isotherms and maximum adsorption capacity varies from 1.06 to 1.81 mg NH3/g dry media. Ammonia biodegradation rates for each organic material were also calculated. Biodegradation rates varied from 0.67 to 7.82 mg NH3/kg media/d depending on the material tested. The data obtained showed important differences in the behaviour of the biofilter organic media, which has important implications in the design and modelling of these systems. Biotechnol. Bioeng. 2007;97: 515–525. © 2006 Wiley Periodicals, Inc.
SEM and 3D synchrotron radiation micro‐tomography in the study of bioceramic scaffolds for tissue‐engineering applications
Authors: Peyrin Françoise , Mastrogiacomo Maddalena , Cancedda Ranieri , Martinetti Roberta 
Published: November 2006

AbstractDifferent biomaterials have been proposed as scaffolds for the delivery of cells and/or biological molecules to repair or regenerate damaged or diseased bone tissues. Particular attention is being given to porous bioceramics that mimic trabecular bone chemistry and structure. Chemical composition, density, pore shape, pore size, and pore interconnection are elements that have to be considered to improve the efficiency of these biomaterials. Commonly, two‐dimensional (2D) systems of analysis such as scanning electron microscope (SEM) are used for the characterization and comparison of the scaffolds. Unfortunately, these systems do not allow a complete investigation of the three‐dimensional (3D) spatial structure of the scaffold. In this study, we have considered two different techniques, that is, SEM and 3D synchrotron radiation (SR) micro‐CT to extract information on the geometry of two hydroxyapatite (HA) bioceramics with identical chemical composition but different micro‐porosity, pore size distribution, and pore interconnection pathway. The two scaffolds were obtained with two different procedures: (a) sponge matrix embedding (scaffold FB), and (b) foaming (scaffold EP). Both scaffolds showed structures suitable for tissue‐engineering applications, but scaffold EP appeared superior with regard to interconnection of pores, surface on which the new bone could be deposited, and percentage of volume available to bone deposition. Biotechnol. Bioeng. 2007;97: 638–648. © 2006 Wiley Periodicals, Inc.
Thermodynamic electron equivalents model for bacterial yield prediction: Modifications and comparative evaluations
Authors: McCarty Perry L. 
Published: November 2006

AbstractModifications are made to an earlier thermodynamic model (TEEM1) for prediction of maximum microbial yields from aerobic and anaerobic as well as heterotrophic and autotrophic growth. The revised model (TEEM2) corrects for lower yields found with aerobic oxidations of organic compounds where an oxygenase is involved and with growth on single‐carbon (C1) compounds. TEEM1 and TEEM2 are based on energy release and consumption as determined from the reduction potential or Gibbs free energy of ½‐reaction reduction equations together with losses of energy during energy transfer. Energy transfer efficiency is a key parameter needed to make predictions with TEEM2, and was determined through evaluations with extensive data sets on aerobic heterotrophic yield available in the literature. For compounds following normal catabolic pathways, the best‐fit value for energy transfer efficiency was 0.37, which permitted accurate predictions of growth with a precision of 15%–20% as determined by standard deviation. Using the same energy transfer efficiency, a similar precision, but somewhat less accuracy was found for organic compounds where oxidation involves an oxygenase (estimates 8% too high) and for C1 compounds (estimates 17% too high). In spite of the somewhat lower accuracy, the TEEM2 modifications resulted in improved predictions over TEEM1 and the comparison models. Biotechnol. Bioeng. 2007;97: 377–388. © 2006 Wiley Periodicals, Inc.
Catalytic Relationships between Type I and Type II Iterative Polyketide Synthases: The Aspergillus parasiticus Norsolorinic Acid Synthase
Authors: Ma Yue , Smith Leah H. , Cox Russell J. , Beltran‐Alvarez Pedro , Arthur Christopher J. , Simpson Thomas J. 
Published: November 2006

AbstractNorsolorinic acid synthase (NSAS) is a type I iterative polyketide synthase that occurs in the filamentous fungus Aspergillus parasiticus. PCR was used to clone fragments of NSAS corresponding to the acyl carrier protein (ACP), acyl transferase (AT) and β‐ketoacyl‐ACP synthase (KS) catalytic domains. Expression of these gene fragments in Escherichia coli led to the production of soluble ACP and AT proteins. Coexpression of ACP with E. coli holo‐ACP synthase (ACPS) let to production of NSAS holo‐ACP, which could also be formed in vitro by using Streptomyces coelicolor ACPS. Analysis by mass spectrometry showed that, as with other type I carrier proteins, self‐malonylation is not observed in the presence of malonyl CoA alone. However, the NSAS holo‐ACP serves as substrate for S. coelicolor MCAT, S. coelicolor actinorhodin holo‐ACP and NSAS AT domain‐catalysed malonate transfer from malonyl CoA. The AT domain could transfer malonate from malonyl CoA to NSAS holo‐ACP, but not hexanoate or acetate from either the cognate CoA or FAS ACP species to NSAS holo‐ACP. The NSAS holo‐ACP was also active in actinorhodin minimal PKS assays, but only in the presence of exogenous malonyl transferases.
Magnetic Face‐to‐Face Interaction and Electrocommunication in Chromium Sandwich Compounds
Authors: Elschenbroich Christoph , Kanellakopulos Basil , Köhler Frank H. , Metz Bernhard , Lescouëzec Rodrigue , Mitzel Norbert W. , Strauß Werner 
Published: November 2006

AbstractThe reaction of [{(C5Me5)CrCl2}2] with [2.2](1,4)cyclophane gave [(C5Me5)Cr{[2.2](1,4)cyclophane}] (1) and [(C5Me5)Cr{[2.2](1,4)cyclophane}Cr(C5Me5)] (2), depending on the reaction conditions. X‐ray structure analysis showed 2 to be a ministack which in turn is stacked in the lattice. The chromium atoms are 6.035 Å apart, and the distortion of the benzene rings to boat‐shaped moieties is less pronounced than in parent [2.2](1,4)cyclophane. The NMR and EPR spectra were consistent with a S=1/2 ground state for 1 and with two interacting S=1/2 centers in 2. Spin density was found in the ligand π systems, where its sign was negative when the π system was adjacent to chromium, while on the nonbonded benzene moiety of 1 it was positive. Cyclic voltammograms showed reductions to 1− and 22−, as well as oxidations to 1+, 2+, and 22+ which were quasireversible, whereas oxidations to 12+ and 23+ were irreversible. Interaction between the metal ions was revealed by a 260 mV separation of the redox waves belonging to 2+, and 22+. Both cations were isolated as [B(C6H5)4]− salts, which in solution decomposed to [2.2](1,4)cyclophane and [(C5Me5)Cr{(η6‐C6H5)B(C6H5)3}] (3). The 1H and 13C NMR spectra of 3 were in accordance with an S=1 ground state. Solid‐state magnetic measurements of the dimetallic compounds showed antiferromagnetic interaction with J=−122 cm−1 for 2, J=−31 cm−1 for 2+ (ground state S=1/2), and J=−23.5 cm−1 for 22+ (with H=−JS1S2). The decrease of J in the series 2, 2+, and 22+ was traced to the number of unpaired electrons and, for the mixed‐valent cation 2+, to additional double exchange.