bluuebunny/crossref_metadata_2025 huggingface dataset:
On the modelling of publish/subscribe communication systems
Authors: Baldoni R. , Beraldi R. , Tucci Piergiovanni S. , Virgillito A.
Published: April 2005

This paper presents a formal framework of a distributed computation based on a publish/subscribe system. The framework abstracts the system through two delays, namely the subscription/unsubscription delay and the diffusion delay. This abstraction allows one to model concurrent execution of publication and subscription operations without waiting for the stability of the system state and to define a Liveness property which gives the conditions for the presence of a notification event in the global history of the system. This formal framework allows us to analytically define a measure of the effectiveness of a publish/subscribe system, which reflects the percentage of notifications guaranteed by the system to subscribers. A simulation study confirms the validity of the analytical measurements. Copyright © 2005 John Wiley & Sons, Ltd.
Distributed filter processes
Authors: Joshi Rushikesh K.
Published: April 2005

A programming model called distributed filter processes for transparent filtering in distributed systems is presented. Filter processes are modeled as extensions to distributed processes. Messages can be captured transparently by intermediate filter processes. The programming abstractions are presented with applications to the evolution of programs. Copyright © 2005 John Wiley & Sons, Ltd.
Benchmarking message‐oriented middleware: TIB/RV versus SonicMQ
Authors: Maheshwari Piyush , Pang Michael
Published: April 2005

Message‐oriented middleware (MOM) has become a vital part of the complex application integration projects. MOM is used to pass data and workflow in the form of messages between different enterprise applications. The performance of integrated applications greatly depends on how effectively the MOM performs. This paper presents a benchmark comparison between two industry well‐known MOMs—TIBCO Rendezvous (TIB/RV) and SonicMQ. Although the two MOMs are very similar in certain respects, their native implementation and architecture are very different. We provide an unbiased benchmark reference to the middleware selection process. The primary objective of our work is to evaluate and compare the MOMs by testing their effectiveness in the delivery of messages in publish/subscribe and point‐to‐point message domains, their program stability and the system resource utilization. Copyright © 2005 John Wiley & Sons, Ltd.
MEAD: support for Real‐Time Fault‐Tolerant CORBA
Authors: Narasimhan P. , Dumitraş T. A. , Paulos A. M. , Pertet S. M. , Reverte C. F. , Slember J. G. , Srivastava D.
Published: April 2005

The OMG's Real‐Time CORBA (RT‐CORBA) and Fault‐Tolerant CORBA (FT‐CORBA) specifications make it possible for today's CORBA implementations to exhibit either real‐time or fault tolerance in isolation. While real‐time requiresa prioriknowledge of the system's temporal operation, fault tolerance necessarily deals with faults that occur unexpectedly, and with possibly unpredictable fault recovery times. The MEAD (Middleware for Embedded Adaptive Dependability) system attempts to identify and to reconcile the conflicts between real‐time and fault tolerance, in a resource‐aware manner, for distributed CORBA applications. MEAD supports transparent yet tunable fault tolerance in real‐time, proactive dependability, resource‐aware system adaptation to crash, communication and timing faults with bounded fault detection and fault recovery. Copyright © 2005 John Wiley & Sons, Ltd.
The First Picoseconds in Bacterial Photosynthesis—Ultrafast Electron Transfer for the Efficient Conversion of Light Energy
Authors: Zinth Wolfgang , Wachtveitl Josef
Published: April 2005

In this Minireview, we describe the function of the bacterial reaction centre (RC) as the central photosynthetic energy‐conversion unit by ultrafast spectroscopy combined with structural analysis, site‐directed mutagenesis, pigment exchange and theoretical modelling. We show that primary energy conversion is a stepwise process in which an electron is transferred via neighbouring chromophores of the RC. A well‐defined chromophore arrangement in a rigid protein matrix, combined with optimised energetics of the different electron carriers, allows a highly efficient charge‐separation process. The individual molecular reactions at room temperature are well described by conventional electron‐transfer theory.
Molecular Photobleaching Kinetics of Rhodamine 6G by One‐ and Two‐Photon Induced Confocal Fluorescence Microscopy
Authors: Eggeling Christian , Volkmer Andreas , Seidel Claus A. M.
Published: April 2005

Under high‐excitation irradiance conditions in one‐ and two‐photon induced fluorescence microscopy, the photostability of fluorescent dyes is of crucial importance for the detection sensitivity of single molecules and for the contrast in fluorescence imaging. Herein, we report on the dependence of photobleaching on the excitation conditions, using the dye Rhodamine 6G as a typical example. The different excitation modes investigated include 1) one‐photon excitation into the first‐excited singlet state in the range of 500 to 528 nm by continuous wave and picosecond‐pulsed lasers and 2) two‐ and one‐photon excitation to higher‐excited singlet states at 800 and 350 nm, respectively, by femtosecond pulses. Experimental strategies are presented, which allow resolving the photophysics. From single‐molecule trajectories and fluorescence correlation spectroscopy, as well as with a simple theoretical model based on steady‐state solutions of molecular rate equation analysis, we determined the underlying photobleaching mechanisms and quantified the photokinetic parameters describing the dependence of the fluorescence signal on the excitation irradiance. The comparison with experimental data and an exact theoretical model show that only minor deviations between the different theoretical approaches can be observed for high‐pulsed excitation irradiances. It is shown that fluorescence excitation is in all cases limited by photolysis from higher‐excited electronic states. In contrast to picosecond‐pulsed excitation, this is extremely severe for both one‐ and two‐photon excitation with femtosecond pulses. Furthermore, the photostability of the higher‐excited electronic states is strongly influenced by environmental conditions, such as polarity and temperature.
High‐Resolution Colocalization of Single Molecules within the Resolution Gap of Far‐Field Microscopy
Authors: Heinlein Thomas , Biebricher Andreas , Schlüter Pia , Roth Christian Michael , Herten Dirk‐Peter , Wolfrum Jürgen , Heilemann Mike , Müller Christian , Tinnefeld Philip , Sauer Markus
Published: April 2005

To obtain detailed information about the three‐dimensional (3D) organization of small biomolecular assemblies with a size of less than 100 nanometers, advanced techniques are required that enable the determination of absolute 3D positions and distances between individual fluorophores well below the resolution limit of conventional light microscopy. We show how spectrally resolved fluorescence lifetime imaging microscopy (SFLIM) can provide significant contributions and allow us to determine distances between conventional individual fluorophores (Bodipy 630/650 and Cy5.5) that are less than 20 nm apart. We take advantage of fluorescent dyes (here Cy5.5 and Bodipy 630/650) that can be efficiently excited by a single pulsed diode laser emitting at 635 nm but differ in their fluorescence lifetime and emission maxima. The potential of the method for ultrahigh colocalization studies is demonstrated by measuring the end‐to‐end distance between single fluorophores separated by double‐stranded DNA of various lengths. Combining SFLIM with polarization‐modulated excitation allows us to obtain, simultaneously, information about the relative orientation of fluorophores. Furthermore, we show that the environment‐dependent photophysics of conventional fluorophores, that is, photostability, blinking pattern, and the tendency to enter irreversible nonfluorescent states, sets certain limitations to their in vitro and in vivo applications.
Green and Red Fluorescent Proteins: Photo‐ and Thermally Induced Dynamics Probed by Site‐Selective Spectroscopy and Hole Burning
Authors: Bonsma S. , Purchase R. , Jezowski S. , Gallus J. , Könz F. , Völker S.
Published: April 2005

The cloning and expression of autofluorescent proteins in living matter, combined with modern imaging techniques, have thoroughly changed the world of bioscience. In particular, such proteins are widely used as genetically encoded labels to track the movement of proteins as reporters of cellular signals and to study protein–protein interactions by fluorescence resonance energy transfer (FRET). Their optical properties, however, are complex and it is important to understand these for the correct interpretation of imaging data and for the design of new fluorescent mutants. In this Minireview we start with a short survey of the field and then focus on the photo‐ and thermally induced dynamics of green and red fluorescent proteins. In particular, we show how fluorescence line narrowing and high‐resolution spectral hole burning at low temperatures can be used to unravel the photophysics and photochemistry and shed light on the intricate electronic structure of these proteins.
Cover Picture: Single‐Molecule Quantum‐Dot Fluorescence Resonance Energy Transfer (ChemPhysChem 5/2005)
Authors: Hohng Sungchul , Ha Taekjip
Published: April 2005

The cover picture shows fluorescence resonance energy transfer (FRET) between single‐molecule quantum dots (green) as donors and organic acceptors (red). The conformational dynamics of a DNA four‐way junction tagged with this FRET pair are observed. Recent discovery of quantum‐dot blinking suppression opened up new opportunities to observe single‐molecule conformational changes using long‐lasting, ultrabright quantum dots. In their article on page 956 T. Ha and S. Hohng show that single‐molecule structural dynamics can be reliably probed using these quantum dots.
Alkaline hemolysis fragility is dependent on cell shape: Results from a morphology tracker
Authors: Ionescu‐Zanetti Cristian , Wang Lee‐Ping , Di Carlo Dino , Hung Paul , Di Blas Andrea , Hughey Richard , Lee Luke P.
Published: April 2005

Background

The morphometric analysis of red blood cells (RBCs) is an important area of study and has been performed previously for fixed samples. We present a novel method for the analysis of morphologic changes of live erythrocytes as a function of time. We use this method to extract information on alkaline hemolysis fragility. Many other toxins lyse cells by membrane poration, which has been studied by averaging over cell populations. However, no quantitative data are available for changes in the morphology of individual cells during membrane poration‐driven hemolysis or for the relation between cell shape and fragility.

Methods

Hydroxide, a porating agent, was generated in a microfluidic enclosure containing RBCs in suspension. Automatic cell recognition, tracking, and morphometric measurements were done by using a custom image analysis program. Cell area and circular shape factor (CSF) were measured over time for individual cells. Implementations were developed in MATLAB and on Kestrel, a parallel computer that affords higher speed that approaches real‐time processing.

Results

The average CSF went through a first period of fast increase, corresponding to the conversion of discocytes to spherocytes under internal osmotic pressure, followed by another period of slow increase until the fast lysis event. For individual cells, the initial CSF was shown to be inversely correlated to cell lifetime (linear regression factor R = 0.44), with discocytes surviving longer than spherocytes. The inflated cell surface area to volume ratio was also inversely correlated to lifetime (R = 0.43) but not correlated to the CSF. Lifetime correlated best to the ratio of cell inflation volume (Vfinal − Vinitial) to surface area (R = 0.65).

Conclusions

RBCs inflate at a rate proportional to their surface area, in agreement with a constant flux model, and lyse after attaining a spherical morphology. Spherical RBCs display increased alkaline hemolysis fragility (shorter lifetimes), providing an explanation for the increased osmotic fragility of RBCs from patients who have spherocytosis. © 2005 Wiley‐Liss, Inc.
Capacitive Biosensor for Glutathione Detection Based on Electropolymerized Molecularly Imprinted Polymer and Kinetic Investigation of the Recognition Process
Authors: Yang Liu , Wei Wanzhi , Xia Jianjun , Tao Han , Yang Pinghua
Published: April 2005

A novel capacitive biosensor based on electropolymerized molecularly imprinted polymer (MIP) for glutathione detection is reported. The capacitive sensor was prepared by electropolymerizing o‐phenylenediamine (o‐PD) on a self‐assembled 2‐mercaptoethane sulfonate (MES) monolayer modified gold electrode in the presence of template glutathione. 1‐Dodecanethiol was used to block the defect of polymer film to improve its dielectric performance. Hydrolization procedure was selected to remove the template thoroughly for better sensitivity. The dielectric property of the sensitive layer was characterized by differential pulse voltammetry (DPV). The linear response range of the sensor for glutathione was between 0.025 and 0.30 mmol L−1 with a detection limit of 1.25×10−3 mmol L−1. Satisfactory results were obtained in the direct detection of real samples. The selectivity was evaluated by capacitance selective coefficient of glutathione and other compounds. The kinetic aspects of the recognition process were investigated by capacitive transduction. A two‐step kinetic model was derived to describe the interaction between analyte and imprint sites. Fitted results were well in agreement with the corresponding experimental results.
A Bis‐Oxime Derivative of Diaza‐18‐Crown‐6 as an Ionophore for Silver Ion
Authors: Goldcamp Michael J. , Ashley Kevin , Edison Sara E. , Pretty Jack , Shumaker Joseph
Published: April 2005

A new pendant‐arm derivative of diaza‐18‐crown‐6, containing two oxime donor groups, has been synthesized and incorporated into a polyvinyl chloride (PVC) membrane ion‐selective electrode. The electrode shows selectivity for Ag+ ion, with a near Nernstian response. Pb2+, Cu2+, Hg2+, and Tl+ are major interfering ions, with Cd2+ having minor interference. The electrode shows no potentiometric response for the ions Mg2+, Al3+, K+, Ca2+, Ni2+, Fe3+, and La3+, and is responsive to H+ at pH<6.
Voltammetric Detection of the DNA Interaction with Toluidine Blue
Authors: Jiao Kui , Li Qing‐Jun , Sun Wei , Wang Zeng‐Jian
Published: April 2005

Binding reactions of toluidine blue (TB) with herring fish DNA in pH 6.0 Britton–Robinson (B–R) buffer solution have been investigated by cyclic voltammetry and linear‐sweep voltammetry at a glassy carbon electrode. TB has a couple of well‐defined redox peaks. The addition of DNA into the TB solution resulted in the decrease of the redox‐peak currents and the shift negatively of the anodic peak potential. The values of the electrochemical parameters such as the electron number of the electrochemical reaction, the electron transfer coefficient and the electrochemical reaction standard rate constant in the absence and presence of DNA, as well as the values of binding constant and binding ratio of DNA with TB were obtained. Almost unchanged values of the electrochemical parameters in the absence and presence of DNA show that nonelectroactive complexes were formed when TB interacted with DNA. DNA concentration can be determined by the decrease of the peak current of TB. The binding mode of TB with DNA was discussed.
Processing lexical semantic and syntactic information in first and second language: fMRI evidence from German and Russian
Authors: Rüschemeyer Shirley‐Ann , Fiebach Christian J. , Kempe Vera , Friederici Angela D.
Published: April 2005

We introduce two experiments that explored syntactic and semantic processing of spoken sentences by native and non‐native speakers. In the first experiment, the neural substrates corresponding to detection of syntactic and semantic violations were determined in native speakers of two typologically different languages using functional magnetic resonance imaging (fMRI). The results show that the underlying neural response of participants to stimuli across different native languages is quite similar. In the second experiment, we investigated how non‐native speakers of a language process the same stimuli presented in the first experiment. First, the results show a more similar pattern of increased activation between native and non‐native speakers in response to semantic violations than to syntactic violations. Second, the non‐native speakers were observed to employ specific portions of the frontotemporal language network differently from those employed by native speakers. These regions included the inferior frontal gyrus (IFG), superior temporal gyrus (STG), and subcortical structures of the basal ganglia. Hum Brain Mapp 25:266–286, 2005. © 2005 Wiley‐Liss, Inc.
P73 functionally replaces p53 in Adriamycin‐treated, p53‐deficient breast cancer cells
Authors: Vayssade Muriel , Haddada Hedi , Faridoni‐Laurens Laetitia , Tourpin Sophie , Valent Alexandre , Bénard Jean , Ahomadegbe Jean‐Charles
Published: April 2005

p53‐related genes, p73 and p63, encode 2 classes of proteins, TA‐p73/p63 and ΔN‐p73/p63. TA‐p73/p63 demonstrate p53‐like properties including gene transactivation and cell death promotion, whereas ΔN‐p73/p63 lack these p53‐like functions. Although p53‐deficient cancer cells are often less responsive to chemotherapy, they are not completely drug resistant, suggesting that other apoptotic pathways are at work. Here, we compared for the first time to our knowledge p73 and p63 activation in various breast cancer (BC) cell lines after Adriamycin (ADR) treatment, an agent considered as mandatory in breast cancer chemotherapy. Our study was carried out using 1 p53‐proficient BC cell line (MCF7 cells) and 3 BC cell lines deficient in p53 response (MCF7/ADRIGR, MDA‐MB157 and T47D) after ADR‐induced genotoxic stress. We report that in cells with no p53 response after ADR treatment, TAp73, but not TAp63 or ΔN‐p73/p63, may replace p53 in triggering not only apoptosis but also cell cycle arrest or DNA repair effectors such as p21, GADD45, 14‐3‐3σ and p53R2. We also demonstrate that TAp73 siRNA inhibits the accumulation of TAp73 in response to ADR treatment in MDA‐MB157 cells and confers protection against ADR. ADR‐induced downregulation of the ΔNp73 isoform in the T47D cell line with nonfunctional mutant p53 further supports anti‐apoptotic function of the isoform antagonistic to both p53 and TA‐p73/p63. Exogenous TAp73 and ΔNp73 overexpression in p53‐response‐deficient cell lines further confirms these results. cDNA microarray techniques demonstrated that the cellular response induced by p73 during ADR treatment could involve specific genes. © 2005 Wiley‐Liss, Inc.
Sulindac corrects defective apoptosis and suppresses azoxymethane‐induced colonic oncogenesis in p53 knockout mice
Authors: Hu Ying , Le Leu Richard K. , Young Graeme P.
Published: April 2005

The acute apoptotic response to genotoxic carcinogens (AARGC) might be important for controlling the subsequent colonic mutational load and progression through oncogenesis. We have found previously that AARGC is p53‐dependent with a gene‐dosage effect, and that decreased AARGC in p53+/− and p53−/− mice is associated with increased susceptibility to carcinogen‐induced oncogenesis. We tested the ability of sulindac to reverse these defects. The effect of sulindac on azoxymethane (AOM)‐induced apoptosis was measured in colonic epithelium in wild‐type, p53+/− and p53−/− mice, 8 hr after a single AOM injection. Sulindac supplementation (0.5 ± 0.1 mg/day) restored defective AARGC in p53+/− but not in p53−/− mice. For effect on colon tumor development, sulindac treatment was started at age 4 weeks in wild‐type, p53+/− and p53−/− mice; three weekly AOM injections were commenced at 6 weeks of age to induce tumors. Sulindac reduced significantly tumor incidence and multiplicity in wild‐type mice (17% and 0.3 tumors/mouse compared to 36% and 0.8 respectively without drug), in p53+/−mice (38% and 0.8 compared to 64% and 1.63) and in p53−/− mice (63% and 1.0 compared to 90% and 1.74). Although loss of p53 function impairs the apoptotic response to AOM‐induced DNA damage, sulindac is capable of partly restoring this defect. As sulindac also reverses the increased risk of oncogenesis due to p53 dysfunction, its enhancement of the apoptotic response to initiating mutations might act to reduce mutational load driving oncogenesis. Sulindac is an effective chemopreventive agent in the presence of p53 dysfunction. © 2005 Wiley‐Liss, Inc.
Tokyo insiders and the informational efficiency of the yen/dollar exchange rate
Authors: Covrig Vicentiu , Melvin Michael
Published: April 2005

When there is a high concentration of informed yen/dollar traders active in Tokyo, theory suggests that there should be a faster adjustment of the yen/dollar exchange rate to the full‐information level. We exploit the data during a period believed to contain a high concentration of informed Japanese traders in order to test this hypothesis. Comparing the period of informed trader clustering to a similar period without the informed, we find that yen/dollar exchange rate quotes adjust to full‐information levels three times faster when the informed are active than when they are not. These results are consistent with a view of the foreign exchange market where private information is at times quite important. Copyright © 2005 John Wiley & Sons, Ltd.
Dimensions of financial integration in Greater China: money markets, banks and policy effects
Authors: Cheung Yin‐Wong , Chinn Menzie D. , Fujii Eiji
Published: April 2005

The financial linkages between the People's Republic of China (hereafter ‘China’) and the other Greater China economies of Hong Kong and Taiwan are assessed, and compared against those of China with Singapore, Japan and the United States. For both sets of links, there is evidence thatex postuncovered interest parity tends to hold over longer periods, and the magnitude of the parity deviations is shrinking over time. The deviations depend upon the extent of capital controls, and in certain cases, exchange rate volatility. However, while the money markets of China are increasingly linked to money markets in the rest of the world, our empirical results suggest that the banking sector—the main source of capital for Chinese firms—remains insulated. Copyright © 2005 John Wiley & Sons, Ltd.
China's role in East‐Asian monetary integration
Authors: Hefeker Carsten , Nabor Andreas
Published: April 2005

Most proposals for East‐Asian monetary cooperation assign a special role to the Japanese yen as anchor currency. We focus on the potential role of the Chinese renminbi. Since China will assume the role of the dominant economy in the region and become a more important destination for Asian products than Japan eventually, this development assigns a special role to the Chinese currency. It is rather unlikely that the renminbi will assume a dominant role immediately, but a comparison with the European monetary integration process suggests designing a system where the relative weight of the renminbi increases gradually. Copyright © 2005 John Wiley & Sons, Ltd.
The effects of the yen/dollar exchange rate on the Korean economy
Authors: Kang Sammo , Kim Soyoung , Wang Yunjong
Published: April 2005

The effects of changes in the yen/dollar exchange rate on the Korean economy during the pre‐crisis and the post‐crisis periods are examined using VAR models. The results show that Korean industrial production does not respond significantly to the depreciation of the Japanese yen against the US dollar during the pre‐crisis period, but that it declines substantially and significantly during the post‐crisis period. The forecast error variance decomposition also confirms that the impact of yen/dollar exchange rate shocks in explaining Korean industrial production is negligible during the pre‐crisis period, but substantial in the post‐crisis period. These empirical results are interesting in that the free‐floating exchange rate regime adopted in the post‐crisis period may be inadequate to insulate the Korean economy from external shocks such as fluctuations in the yen/dollar exchange rate. Copyright © 2005 John Wiley & Sons, Ltd.
Modulation of UDP‐glucuronosyltransferase 1A1 in primary human hepatocytes by prototypical inducers
Authors: Smith Cornelia M. , Faucette Stephanie R. , Wang Hongbing , LeCluyse Edward L.
Published: April 2005

The primary objective of this study was to evaluate the modulation of UGT1A1 expression in human hepatocytes using prototypical CYP450 inducers. A bank of 16 human livers was utilized to obtain an estimate of the range of UGT1A1 protein expression and catalytic activity. Concentration‐dependent changes in UGT1A1 response were evaluated in hepatocyte cultures after treatment with 3‐methylchloranthrene, β‐napthoflavone, rifampicin, or phenobarbital. Pharmacodynamic analyses of UGT1A1 expression were conducted and compared to those of CYP450 after treatment with inducers in 2–3 different hepatocyte preparations. Additionally, expression of UGT1A1 mRNA and protein was evaluated in human hepatocytes treated with 14 different compounds known to activate differentially the human pregnane‐X‐receptor or constitutive androstane receptor. Pharmacodynamic modeling revealed EC50 values statistically significant between UGT1A1 and CYP2B6 after treatment with PB, but not statistically distinguishable between UGT1A1 and CYP's 1A2 or 3A4 after treatment with 3‐methylchloranthrene or rifampicin, respectively. UGT1A1 was most responsive to the pregnane‐X‐receptor‐agonists rifampicin, ritonavir, and clotrimazole at the mRNA level and, to a lesser extent, the constitutive androstane receptor‐activators, phenobarbital and phenytoin. Pharmacodynamic analyses support a mechanism of coordinate regulation between UGT1A1 and a number of CYP450 enzymes by multiple nuclear receptors. © 2005 Wiley Periodicals, Inc. J Biochem Mol Toxicol 19:96–108, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/jbt.20058
Effects of age and pregnancy on cytochrome P450 induction by octamethyltetracyclosiloxane in female Sprague‐Dawley rats
Authors: Falany Charles N. , Li Ge
Published: April 2005

Dimethylcyclosiloxanes (DMCS) are components of silicone gel containing implants and are known inducers of human drug metabolizing enzymes. The effects of the major DMCS, octamethyltetracyclosiloxane (D4) on cytochrome P450 (CYP) induction were examined in young adult, mature, and pregnant female Sprague‐Dawley rats. Also, the ability of D4 administered to pregnant dams to affect CYP expression in fetal liver was examined. Female young, mature, and pregnant Sprague‐Dawley rats were administered 0, 5, 20, and 100 mg/kg D4 daily by gavage for 8 days. Liver microsomal CYP (CYP2B, CYP3A, CYP1A) concentrations were evaluated by Western blots using specific antisera, and CYP activities were assayed using CYP selective assays. D4 treatment resulted in a significant induction of CYP2B and CYP3A isoforms. CYP induction was dose and age dependent. A comparison of the inducibility of CYP3A protein by D4 in rats from different age groups showed that the degree of increase was the highest in the pregnant rats at doses of 20 mg/kg D4 or higher. The mature rats had a lesser degree of responsiveness than did the young rats at the dose of 100 mg/ kg D4. Significant increases in CYP2B immunoreactive protein concentrations were observed in young and mature rats given D4 at doses >5 mg/kg and in pregnant rats at doses >20 mg/kg. Maximal CYP2B induction detected with blotting was more than 90‐fold in mature rats; however, no significant changes were detected in CYP1A expression. There was a 20% increase of liver to body weight ratio in the mature rats treated with 100 mg/kg D4. D4 has different inductive properties in female rats of different ages and reproductive status. Also, D4 administered to the pregnant dam is capable of inducing CYP expression in fetal liver as well as decreasing fetal body weight. © 2005 Wiley Periodicals, Inc. J Biochem Mol Toxicol 19:129–138, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/jbt.20059
Toxicity of short‐chain alcohols to the nematode Caenorhabditis elegans: A comparison of endpoints
Authors: Thompson Grace , de Pomerai David I.
Published: April 2005

The toxicities of 4 short‐chain alcohols—namely methanol, ethanol, iso‐propanol and iso‐butanol—were compared in the nematode Caenorhabditis elegans using several different ecotoxicological endpoints. Range‐finding tests were conducted using transgenic PC161 worms carrying a double reporter construct (GFP plus lacZ) linked to the stress‐inducible hsp16‐1 promoter. These tests showed little response from the GFP reporter, but gave good dose–response curves for the lacZ reporter—showing clear induction at 0.5% v/v ethanol in an overnight assay, but only at 4% in a shorter 6‐h assay. Comparison of the short‐term dose–response curves shows a confusing pattern of differences between the four alcohols tested, although dose‐dependence is evident across at least part of the concentration range. Feeding inhibition assays are somewhat inconclusive with regard to alcohol type, although iso‐butanol and iso‐propanol appear more toxic than ethanol, while methanol is least toxic. To resolve some of the remaining ambiguities, we also used a fecundity assay to show that iso‐propanol is more toxic than ethanol, and a lethality assay to show that iso‐butanol is more toxic than iso‐propanol. Most of the endpoints studied are consistent with the following order of toxicity: iso‐butanol > iso‐propanol > ethanol ≥ methanol. © 2005 Wiley Periodicals, Inc. J Biochem Mol Toxicol 19:87–95, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/jbt.20060
Characterization of adjacent E‐box and nuclear factor 1‐like DNA binding sequence in the human CYP1A2 promoter
Authors: Narvaez Marta J. , Anderson Garret R. , Pickwell George V. , Quattrochi Linda C.
Published: April 2005

To better understand the molecular mechanisms of cytochrome P450 1A2 (CYP1A2) regulation, we have characterized a region of the promoter (+3 to −176) that contains a single E‐box and an adjacent nuclear factor 1 (NF1)‐like DNA binding site. The E‐box was shown to specifically bind nuclear proteins that were recognized by antibodies against upstream stimulatory factor (USF) 1 and 2. Comparison of NF1 binding proteins in HepG2 cells and primary cultures of rat hepatocytes revealed different patterns of DNA–protein complexes, all of which were recognized by a general NF1 antibody. Mutations of the E‐box resulted in substantial reduction of promoter activity in either primary hepatocytes or HepG2 cells regardless of the presence in the reporter constructs of other CYP1A2 regulatory elements, such as the hepatic nuclear factor 1 (HNF‐1) binding site. In contrast, reporter gene activity of the promoter construct harboring the mutated NF1‐like binding site was affected by upstream sequences when transfected into HepG2 cells, but not in primary hepatocytes. We conclude that both USF proteins and different isoforms of NF1 contribute to the constitutive expression of CYP1A2. © 2005 Wiley Periodicals, Inc. J Biochem Mol Toxicol 19:78–86, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/jbt.20063
Risk factors for pancreatic cancer
Authors: Lowenfels Albert B. , Maisonneuve Patrick
Published: April 2005

In the United States, the cumulative mortality or lifetime risk of dying from pancreatic cancer is about 1–2%, but although this form of cancer is rare, nearly all patients die from the disease within one to two years. Because of its lethality, pancreatic cancer now ranks fourth as a cause of death from cancer. There are country‐specific differences in rates, perhaps explained by differences in life‐style factors or diet. African‐Americans in the USA have rates that are about 50% higher than Caucasians. Smoking is the major known risk factor for this cancer, explaining 20–30% of all cases. Another 5–10% of causes are caused by germline mutations, with mutations in BRCA2 being the most frequent. Two background diseases increase the risk of pancreatic cancer—pancreatitis, and diabetes. Major challenges presented by this cancer are: 1) determination of the molecular pathways that make this cancer so aggressive; 2) development of new modalities, perhaps based on proteomics, to enhance early detection. J. Cell. Biochem. 95: 649–656, 2005. © 2005 Wiley‐Liss, Inc.
Continuous precipitation of calcium sulfate dihydrate from waste sulfuric acid and lime
Authors: Gominšek Tomi , Lubej Andrej , Pohar Ciril
Published: April 2005

Precipitation of calcium sulfate dihydrate, gypsum, from (i) a pure sulfuric acid/lime suspension and (ii) a waste sulfuric acid/lime suspension in a continuous pilot plant in the temperature range from 40 °C to 80 °C was studied. It was observed that in the case of waste sulfuric acid with a high content of Mg2+ and Fe2+ ions, several hours after the beginning of the precipitation, partial dissolution of the product and modification of the crystals from needle‐ and plate‐like to agglomerated structures occurred. It is suggested that the secondary changes occur due to the increased concentration of Mg2+ and Fe2+ ions in the reactor. Below 60 °C, and above 70 °C plate‐like and needle‐like single crystals respectively were formed. The mean size (d50) of the crystals was found to increase with increasing temperature and decrease with the initial concentration of lime. Gypsum produced between 70 °C and 80 °C is suitable for further processing for construction plaster. In a precipitation process with pure sulfuric acid only single perfect needle‐like crystals occurred. Copyright © 2005 Society of Chemical Industry
Prediction of microbial growth rate in biofilters by using the nutrient diffusion coefficient
Authors: Chan Wu‐Chung , Lin Zong‐Yi
Published: April 2005

In this study, an optimal process for preparing a synthetic filter material with nitrogen nutrient (PVA/peat/KNO3 composite beads) was developed for biofiltration and the optimal initial nitrogen concentration of the boric acid and phosphate aqueous solutions was found to be 3.94 and 1.52 g nitrogen L−1, respectively. The water‐soluble nitrogen content in the prepared composite beads was higher than that of the compost. The mass transport process for the water‐soluble nitrogen dissolving out of the composite beads occurred in two stages: external mass transport occurred in the early stage and an intraparticle diffusion process occurred in the long‐term stage. The rate of water‐soluble nitrogen dissolving out during the external mass transport process increased with increasing the concentration of KNO3 aqueous solution and that during the intraparticle diffusion process had a maximum value for the composite beads that had been immersed in 0.384 M KNO3. The path of water‐soluble nitrogen dissolving out from the composite beads was that the water‐soluble nitrogen dispersed in the peat phase firstly diffused into the outer poly(vinyl alcohol) (PVA) phase and then it diffused out of the bead surface. The percentage of volatile organic compounds (VOCs) removed by the biofilter from an air stream remained above 99% for 230 days for the composite beads that had been immersed in KNO3 before packing. The microbial growth rate had a maximum value for the composite beads that had been immersed in 0.384 M KNO3 and was higher than that of the compost by a factor of 1.49. The rate of nitrogen dissolving out during the intraparticle diffusion process could be used as an index to predict the microbial growth rate in the biofilter. Copyright © 2005 Society of Chemical Industry
Chemoenzymatic Synthesis of Branched Polymers
Authors: Peeters Joris W. , Palmans Anja R. A. , Meijer E. W. , Koning Cor E. , Heise Andreas
Published: April 2005

Summary: The combination of enzymatic polymerization with ATRP for the synthesis of branched (block) copolymers was investigated. Heterotelechelic polycaprolactone macroinimer was synthesized in a one‐pot enzymatic procedure by using 2‐hydroxyethyl α‐bromoisobutyrate as a bifunctional initiator. A polymerizable end group was introduced by subsequent in situ enzymatic acrylation with vinyl acrylate. Branched polymers were obtained by subsequent atom transfer radical polymerization (ATRP).

Enzymatic synthesis of heterotelechelic macromonomers and subsequent self condensing vinyl polymerization by ATRP.

image

Enzymatic synthesis of heterotelechelic macromonomers and subsequent self condensing vinyl polymerization by ATRP.
The Mechanical Deformation Process of Electrospun Polymer Nanocomposite Fibers
Authors: Kim Gyeong‐Man , Lach Ralf , Michler Goerg Hannes , Chang Young‐Wook
Published: April 2005

Summary: The mechanical deformation processes of poly(methyl methacrylate)/ montmorillonite nanocomposites and their electrospun fibers were investigated by in situ tensile tests under a transmission electron microscope depending on their morphology. While the polymer nanocomposites deformed in a brittle manner, i.e., crazing, the electrospun polymer nanocomposite fibers deformed through a shear flow process leading to “nanonecking” due to the strong overlap of stress fields caused by nanopores within the fiber under a uniaxial tensile load. This unique change in deformation behavior provides the possibility that the intrinsic brittle material could be manipulated to be ductile without sacrificing its other attractive properties through a well‐controlled electrospinning process.

TEM micrograph of a low temperature fractured fiber showing the nanoporous surface structure.

image

TEM micrograph of a low temperature fractured fiber showing the nanoporous surface structure.
Hollow Cu‐NP Spheres Made from Electroless Cu Deposition with Colloidal Particles as Templates
Authors: Cong Hailin , Zhang Maofeng , Cao Weixiao
Published: April 2005

Summary: Hollow copper nanoparticle (Cu‐NP) spheres with different wall thicknesses were prepared with organic and inorganic colloids as core combining self‐assembly and electroless Cu deposition techniques. The hollow Cu‐NP spheres made from polymeric colloids possessed a thicker wall but were easy to break in the removal of the core by THF, while those from SiO2 colloids had thinner wall and remained intact in the removal of the core by HF.

TEM image of the hollow Cu‐NP spheres.

image

TEM image of the hollow Cu‐NP spheres.
Effect of the Brush Structure on the Degradation Mechanism of Polystyrene–Clay Nanocomposites
Authors: Chen Kai , Susner Michael A. , Vyazovkin Sergey
Published: April 2005

Summary: Pyrolysis‐GC‐MS and TGA‐FT‐IR methods have been used to perform a comparative degradation study of polystyrene and a polystyrene–clay composite. An abnormally high yield of α‐methylstyrene has been detected for the composite. This and other differences in degradation products have been explained by enhanced intermolecular interaction of the grafted PS chains, forming a brush structure. A conceptual model of the process has been suggested.

GC pyrograms of virgin PS (A) and PS–clay composite (B) pyrolyzed at 500 °C (1: styrene; 2: 2,4‐diphenylbut‐1‐ene; 2′: dimer derivatives; 3: 2,4,6‐triphenylhex‐1‐ene; 3′: trimer derivatives; 4: α‐methylstyrene).

image

GC pyrograms of virgin PS (A) and PS–clay composite (B) pyrolyzed at 500 °C (1: styrene; 2: 2,4‐diphenylbut‐1‐ene; 2′: dimer derivatives; 3: 2,4,6‐triphenylhex‐1‐ene; 3′: trimer derivatives; 4: α‐methylstyrene).
Monodisperse polystyrene microspheres prepared by dispersion polymerization with microwave irradiation
Authors: Xu Zu‐Shun , Deng Zi‐Wei , Hu Xiao‐Xi , Li Lei , Yi Chang‐Feng
Published: April 2005

Monodisperse polystyrene microspheres with diameters of 200–500 nm were prepared by dispersion polymerization with microwave irradiation with poly(N‐vinylpyrrolidone) as a steric stabilizer and 2,2′‐azobisisobutyronitrile as a radical initiator in an ethanol/water medium. The morphology, size, and size distribution of the polystyrene microspheres were characterized with transmission electron microscopy and photon correlation spectroscopy, and the formed films of the polystyrene dispersions were characterized with atomic force microscopy. The effects of the monomer concentration, stabilizer concentration, and initiator concentration on the size and size distribution of the polystyrene microspheres were investigated. The polystyrene microspheres prepared by dispersion polymerization with microwave irradiation were smaller, more uniform, and steadier than those obtained with conventional heating. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 2368‐2376, 2005
Geometric cooperativity and anticooperativity of three‐body interactions in native proteins
Authors: Li Xiang , Liang Jie
Published: April 2005

Characterizing multibody interactions of hydrophobic, polar, and ionizable residues in protein is important for understanding the stability of protein structures. We introduce a geometric model for quantifying 3‐body interactions in native proteins. With this model, empirical propensity values for many types of 3‐body interactions can be reliably estimated from a database of native protein structures, despite the overwhelming presence of pairwise contacts. In addition, we define a nonadditive coefficient that characterizes cooperativity and anticooperativity of residue interactions in native proteins by measuring the deviation of 3‐body interactions from 3 independent pairwise interactions. It compares the 3‐body propensity value from what would be expected if only pairwise interactions were considered, and highlights the distinction of propensity and cooperativity of 3‐body interaction. Based on the geometric model, and what can be inferred from statistical analysis of such a model, we find that hydrophobic interactions and hydrogen‐bonding interactions make nonadditive contributions to protein stability, but the nonadditive nature depends on whether such interactions are located in the protein interior or on the protein surface. When located in the interior, many hydrophobic interactions such as those involving alkyl residues are anticooperative. Salt‐bridge and regular hydrogen‐bonding interactions, such as those involving ionizable residues and polar residues, are cooperative. When located on the protein surface, these salt‐bridge and regular hydrogen‐bonding interactions are anticooperative, and hydrophobic interactions involving alkyl residues become cooperative. We show with examples that incorporating 3‐body interactions improves discrimination of protein native structures against decoy conformations. In addition, analysis of cooperative 3‐body interaction may reveal spatial motifs that can suggest specific protein functions. Proteins 2005. © 2005 Wiley‐Liss, Inc.
Rapid assessment of contact‐dependent secondary structure propensity: Relevance to amyloidogenic sequences
Authors: Yoon Sukjoon , Welsh William J.
Published: April 2005

We have previously demonstrated that calculation of contact‐dependent secondary structure propensity (CSSP) is highly sensitive in detecting non‐native β‐strand propensities in the core sequences of known amyloidogenic proteins. Here we describe a CSSP method based on an artificial neural network that rapidly and accurately quantifies the influence of tertiary contacts (TCs) on secondary structure propensity in local regions of protein sequences. The present method exhibited 72% accuracy in predicting the alternate secondary structure adopted by chameleon sequences located in highly disparate TC regions. Analysis of 1930 nonhomologous protein domains reveals that the α‐helix and the β‐strand largely share the same sequence context, and that tertiary context is a major determinant of the native conformation. Conversely, it appears that the propensity of random coils for either the α‐helix or the β‐strand is largely invariant to tertiary effects. The present CSSP method successfully reproduced the amyloidogenic character observed in local regions of the human islet amyloid polypeptide (hIAPP). Furthermore, CSSP profiles were strongly correlated (r = 0.76) with the observed mutational effects on the aggregation rate of acylphosphatase. Taken together, these results provide compelling evidence in support of the present CSSP approach as a sensitive probe useful for analysis of full‐length proteins and for detection of core sequences that may trigger amyloid fibril formation. The combined speed and simplicity of the CSSP method lends itself to proteome‐wide analysis of the amyloidogenic nature of common proteins. Proteins 2005. © 2005 Wiley‐Liss, Inc.
Form and function of the corpus luteum during the human menstrual cycle
Authors: Baerwald A. R. , Adams G. P. , Pierson R. A.
Published: April 2005

Objective

To characterize the growth and regression of the corpus luteum (CL) during an interovulatory interval (IOI) using serial transvaginal ultrasonography.

Methods

Fifty healthy women of reproductive age with a history of regular menstrual cycles underwent daily transvaginal ultrasonography for one IOI. Measurements of luteal area and luteal numerical pixel value (NPV) were recorded each day after ovulation until the CL could no longer be detected. Blood was drawn every third day during the IOI to measure serum concentrations of progesterone and estradiol‐17β.

Results

Corpora lutea were of two morphological types: those with a central fluid‐filled cavity (CFFC) (78%) and those without (22%). Eighty‐eight percent of women exhibited a CL containing a CFFC 2 days after ovulation, followed by 34% 13 days after ovulation and 2% 27 days after ovulation. Luteal area, progesterone concentration and estradiol concentration increased for approximately the first 6 days following ovulation followed by a subsequent decline. Luteal NPV decreased from days 1 to 11 and increased during days 11–16. Changes in luteal area, NPV, progesterone and estradiol concentrations did not differ in women with two versus three waves of follicular development.

Conclusions

Peak luteal function, as determined by maximum luteal area, progesterone concentration and estradiol concentration, is observed 6 days following ovulation. Luteal NPV is reflective of morphological and endocrinological changes in the CL. The development of a CFFC during luteinization is a normal physiological phenomenon. The CL can be detected, but is not functional, during the follicular phase of the menstrual cycle. Copyright © 2005 ISUOG. Published by John Wiley & Sons, Ltd.