bluuebunny/crossref_metadata_2025_split huggingface dataset:
Inosine monophosphate dehydrogenase (IMPDH) as a target in drug discovery
Authors: Shu Qingning , Nair Vasu 
Published: May 2007

AbstractInosine monophosphate dehydrogenase (IMPDH) is a key enzyme of de novo purine nucleotide biosynthesis and is viewed as an important target in the quest for discovery of drugs in the antiviral, antibacterial and anticancer therapeutic areas. This review focuses on the medicinal chemistry, drug discovery and chemical biology of IMPDH. Examples of IMP and cofactor site‐directed inhibitors, allosteric inhibitors and isoform‐selective inhibitors are presented. Comparison of IMPDHs from different organisms is also made to facilitate the design of species‐selective IMPDH inhibitors for drug discovery. Special emphasis in the review is placed on IMPDH from Mycobacterium tuberculosis. © 2007 Wiley Periodicals, Inc. Med Res Rev, 28, No. 2, 219–232, 2008
Investigation of the Gel Effect in Reactive Extrusion Processes for Free Radical Polymerization
Authors: Zhang Guofang , Jia Yuxi , Sun Sheng , Wu Lili , Zhao Guoqun , An Lijia 
Published: May 2007

AbstractThe gel effect in the reactive extrusion process for free radical polymerization in a closely intermeshing co‐rotating twin screw extruder was investigated. First the reaction kinetic model was constructed mainly on the basis of entanglement theory. Next, numerical calculation expressions for the initiator and monomer concentrations, monomer conversion, average molecular weight and apparent viscosity were deduced. Finally, the evolution of the above variables were shown and discussed for the example of butyl methacrylate. The simulated results of the monomer conversion are in good agreement with experimental results.magnified image
Industrial SBR Process: Computer Simulation Study for Online Estimation of Steady‐State Variables Using Neural Networks
Authors: Minari Roque J. , Stegmayer Georgina S. , Gugliotta Luis M. , Chiotti Omar A. , Vega Jorge R. 
Published: May 2007

AbstractThis work investigates the industrial production of styrene‐butadiene rubber in a continuous reactor train, and proposes a soft sensor for online monitoring of several processes and polymer quality variables in each reactor. The soft sensor includes two independent artificial neural networks (ANN). The first ANN estimates monomer conversion, solid content, polymer production, average particle diameter, and average copolymer composition; the second ANN estimates average molecular weights and average branching degrees. The required ANN inputs are: (i) the reagent feed rates into the first reactor and (ii) the reaction heat rate in each reactor. The proposed ANN‐based soft sensor proved robust to several measurement errors, and is suitable for online estimation and closed‐loop control strategies.magnified image
Prediction of Chain Length Distribution of Polystyrene Made in Batch Reactors with Bifunctional Free‐Radical Initiators Using Dynamic Monte Carlo Simulation
Authors: Maafa Ibrahim M. , Soares João B. P. , Elkamel Ali 
Published: May 2007

AbstractThe objective of this paper is to present a dynamic Monte Carlo model that is able to simulate the polymerization of styrene with bifunctional free‐radical initiators in a batch reactor. The model can predict the dynamic evolution of the chain length distribution of polystyrene in the reactor. The model includes all relevant polymerization mechanistic steps, including chemical and thermal radical generation, and diffusion‐controlled termination. The model was applied to styrene polymerization and the Monte Carlo estimates for chain length averages were compared to those obtained with the method of moments. Excellent agreement was obtained between the two methods. Although styrene polymerization was used as a case study, the proposed methodology can be easily extended to any other polymer type made by free‐radical polymerization.magnified image
The effects of ovariectomy and estrogen replacement on acetylcholine release from nerve fibres and passive stretch‐induced acetylcholine release in female rat bladder
Authors: Yoshida Junya , Aikawa Ken , Yoshimura Yasukuni , Shishido Keiichi , Yanagida Tomohiko , Yamaguchi Osamu 
Published: May 2007

AbstractAimsThe present study investigated the effects of ovariectomy and estrogen replacement on the release of acetylcholine (Ach) from cholinergic neurons as well as on the tetrodotoxin (TTX)‐insensitive stretch‐induced Ach release in isolated rat detrusor. In addition, the above effects on rat micturition characteristics were also studied.MethodsThirty female rats randomly received a sham operation, ovariectomy, or ovariectomy plus estrogen replacement. Using metabolic cages, micturition parameters were recorded. Then, in vitro functional experiments that included the measurements of nerve‐mediated detrusor muscle contraction, Ach release from nerve fibres, and stretch‐induced TTX‐insensitive Ach release were performed. Ach release was measured using microdialysis and high‐performance liquid chromatography.ResultsOvariectomized rats showed a significant decrease in voided volume and significant increase in 24‐hr frequency of voiding. Ovariectomy caused the significant increase in both TTX‐insensitive basal Ach release and TTX‐insensitive stretch‐induced Ach release. On the other hand, ovariectomy caused a significant decrease in Ach release from nerve fibres, resulting in the decrease in the contractile responses of detrusor muscle to electrical nerve stimulation. Estrogen replacement restored these alterations induced by ovariectomy.ConclusionsOur findings showed that as a results of estrogen deficiency, Ach release from nerve fibres decreased, suggesting that this reduction of Ach released from cholinergic nerves may cause the decrease in detrusor contractility. Furthermore, this study also demonstrated that stretch‐induced TTX‐insensitive Ach release was increased by ovariectomy. This may be a contributing factor to the development of overactive bladder in elderly women. Neurourol. Urodynam. 26:1050–1055, 2007. © 2007 Wiley‐Liss, Inc.
Pudendal nerve stimulation evokes reflex bladder contractions in persons with chronic spinal cord injury
Authors: Yoo Paul B. , Klein Stephen M. , Grafstein Neil H. , Horvath Eric E. , Amundsen Cindy L. , Webster George D. , Grill Warren M. 
Published: May 2007

AbstractAimsAlthough electrical stimulation of the pudendal nerve has been shown to evoke reflex micturition‐like bladder contractions in both intact and spinalized cats, there is little evidence to suggest that an analogous excitatory reflex exists in humans, particularly those with spinal cord injury (SCI). We present two cases where electrical activation of pudendal nerve afferents was used to evoke excitatory bladder responses.Subjects and MethodsA percutaneously placed catheter electrode was used to electrically stimulate the pudendal nerve trunk in two males with SCI. The response was quantified with recorded changes in detrusor pressure and EMG activity of the external anal sphincter.ResultsIn both individuals, frequency specific (f = 20–50 Hz) activation of the pudendal nerve trunk evoked excitatory bladder contractions that also depended on the stimulus amplitude and bladder volume.ConclusionThe results suggest that selective activation of the perineal branches of the pudendal nerve may further augment the excitatory reflex evoked by electrical stimulation. Neurourol. Urodynam. 26:1020–1023, 2007. © 2007 Wiley‐Liss, Inc.
A posteriori error estimates of mixed methods for miscible displacement problems
Authors: Chen Yanping , Liu Wenbin 
Published: May 2007

AbstractThe miscible displacement of one incompressible fluid by another in a porous medium is governed by a system of two equations. One is an elliptic equation of the pressure and the other is a parabolic equation of the concentration of one of the fluids. Since the pressure appears in the concentration only through its velocity field, we choose a mixed finite element method to approximate the pressure equation and for the concentration we use the standard Galerkin method. We shall obtain an explicit a posteriori error estimator in L2(L2) for the semi‐discrete scheme applied to the non‐linear coupled system. Copyright © 2007 John Wiley & Sons, Ltd.
Laparoscopic versus open abdominal surgery in children with sickle cell disease is associated with a shorter hospital stay
Authors: Goers Trudie , Panepinto Julie , DeBaun Michael , Blinder Morey , Foglia Robert , Oldham Keith T. , Field Joshua J. 
Published: May 2007

AbstractBackgroundLimited information exists comparing the post‐operative complication rate of laparoscopic or open abdominal surgeries in children with sickle cell disease (SCD). The primary objective of this study was to compare the outcomes in children with SCD who required laparoscopic or open abdominal surgery for a cholecystectomy or splenectomy.ProcedureWe conducted a retrospective analysis of laparoscopic and open abdominal surgeries performed in children with SCD (ages 0–20 years) at two medical centers from 1984 to 2004. The primary outcome measures were the rates of post‐operative pain and acute chest syndrome (ACS) episodes following laparoscopic or open abdominal surgery. The secondary outcome was length of hospital stay following surgery. We also examined the potential contribution of pre‐operative (transfusion) and intra‐operative factors (operating time, estimated blood loss, and end‐operative temperature) to post‐operative SCD‐related complications.ResultsA total of 140 cases were identified, 98 laparoscopic and 42 open. Episodes of post‐operative pain and ACS episodes were comparable between laparoscopic and open procedures (pain: 4% vs. 3%, P = 0.619; ACS: 5% vs. 5%, P = 0.933). Additionally, laparoscopic surgeries were associated with a significantly shorter hospital stay (2.9 vs. 5.4 days, 95% CI −3.7 to −1.4, P < 0.001). There was no difference in the number of hospital readmissions within 1 month of the surgery.ConclusionsFor children with SCD who need a cholecystectomy or splenectomy, laparoscopy is the preferred strategy because of a shorter hospital stay with a similar complication rate compared to open surgeries. Pediatr Blood Cancer 2008;50:603–606. © 2007 Wiley‐Liss, Inc.
Thermomechanical studies of aluminum nitride filled shape memory polymer composites
Authors: Razzaq Muhammad Yasar , Frormann Lars 
Published: May 2007

AbstractHigh thermal conductivity polyurethane shape memory polymer (SMP) composites filled with aluminum nitride (AlN) were fabricated, and their thermal and thermomechanical properties were studied. The purpose of this microstructure is to improve the thermal properties of the SMPs at low filler content. Morphology of AlN filler in polyurethane SMP matrix and the resulting thermal conductivity was also investigated. Thermal studies have shown that AlN is an effective filler for reinforcement of the polyurethane SMP and that it does not deteriorate the stable physical crosslink structure of the polyurethane, which is necessary to store the elastic energy in the service process of the shape memory material. The thermal conductivities of these SMP composites in relation to filler concentration and temperature were investigated, and it was found that the thermal conductivity can increase up to 50 times in comparison with that of the pure SMP. Furthermore, differential scanning calorimetry tests have shown a significant decrease in the glass transition temperature of the switching segment. Dynamic mechanical studies have shown that the storage modulus of the composites increase with higher AlN content in both glassy and rubbery state. Damping peak decreases and also the curve of damping becomes broader with increasing filler content. Strain fixity rate which expresses the ability of the specimens to fix their strain has been improved slightly in the presence of AlN filler but the final recovery rate of the shape memory measurement has decreased evidently. POLYM. COMPOS., 28:287–293, 2007. © 2007 Society of Plastics Engineers
Kevlar and glass fiber treatment for thermoplastic composites by step polycondensation
Authors: Salehi‐Mobarakeh H. , Nakata S. , Ait‐Kadi A. , Brisson J. 
Published: May 2007

AbstractNylon‐6,6 was grafted at the surface of glass and plasma‐treated Kevlar fibers for use in nylon–Kevlar thermoplastic composites. Hydroxyl and, in the case of Kevlar, amine end‐groups occur at the fibre surface, either as defects or due to the plasma treatment. These were used as anchor points for nylon‐6,6 step polycondensation. Fibers were subjected to successive dipping in adipoyl chloride/CH2Cl2 and aqueous hexamethylenediamine solutions in order to attach and grow high molecular weight polymer on the fiber surface. Grafted nylon was characterized by Fourier transform infrared spectroscopy, proton nuclear magnetic resonance, differential scanning calorimetry and thermogravimetry. It was shown that no backbiting occurred during the first stage of the grafting process and that the polymer quantity increased linearly with number of passes, up to ∼50 passes for plasma‐treated Kevlar and 100 for glass fibers, after which polymer quantity remained constant, within experimental error, which was attributed to the onset of termination reactions. POLYM. COMPOS., 28:278–286, 2007. © 2007 Society of Plastics Engineers
Ground currents in single‐phase transformerless photovoltaic systems
Authors: Gubía Eugenio , Sanchis Pablo , Ursúa Alfredo , López Jesús , Marroyo Luis 
Published: May 2007

AbstractThe relative weight of the energy generated by means of renewable sources is constantly increasing. Among all these sources, the photovoltaic (PV) systems present the higher and more stable relative growth. However, the PV system is still too expensive and a significant effort is being done to increase the efficiency and reduce the cost. Concerning the PV inverters, this has lead to the elimination of the low frequency (LF) transformer that has been traditionally included. The LF transformer provides isolation from the grid but reduces the PV inverter efficiency and increases its size and cost. However, the elimination of the transformer might generate strong ground currents, which become now an important design parameter for the PV inverter. The ground currents are a function of the system stray elements. However, there is no simple model and procedure to study the common mode behavior of a PV system, which is required to analyze the ground currents. In this paper, a comprehensible model is proposed which provides a better understanding of the common mode issue in single‐phase transformerless PV systems. In addition, a procedure is developed to analyze the global performance, efficiency, grid current quality, and common mode behavior of a PV inverter as a function of its particular structure and modulation technique. Copyright © 2007 John Wiley & Sons, Ltd.
Novel poly(pyridine imide) with pendent naphthalene groups: Synthesis and thermal, optical, electrochemical, electrochromic, and protonation characterization
Authors: Liaw Der‐Jang , Wang Kun‐Li , Chang Feng‐Chyuan , Lee Kueir‐Rarn , Lai Juin‐Yih 
Published: May 2007

AbstractA new diamine containing a pyridine heterocyclic group and a naphthalene substituent, 4‐(2‐naphthyl)‐2,6‐bis(4‐aminophenyl) pyridine (NBAPP), was synthesized with the Chichibabin reaction and used in the preparation of poly(pyridine imide) by direct polycondensation with 4,4′‐hexafluoroisopropylidenediphathalic anhydride in N‐methyl‐2‐pyrrolidinone (NMP). The poly(pyridine imide) derived from diamine NBAPP with naphthalene substituents was highly organosoluble: it was soluble in tetrahydrofuran, NMP, N,N‐dimethylacetamide (DMAc), N,N‐dimethylformamide, and γ‐butyrolactone at room temperature and in pyridine, dimethyl sulfoxide, and cyclohexanone upon heating at 70 °C. The poly(pyridine imide) was converted into lightly colored, optically transparent, flexible, and tough polyimide films via casting onto glass from a DMAc solution. This polymer exhibited good thermal stability (temperature of 10% weight loss = 527 °C) in air and high dielectric constants (as high as 4.20 at 1 kHz). The polyimide films had a tensile strength of 102 MPa and a tensile modulus of 1.8 GPa. As for the optical properties, the polymer exhibited UV–vis absorption bands in the region of 223–450 nm and possessed strong green‐yellow fluorescence (500 nm) after being protonated with acid. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 2367–2374, 2007
The fluorescence transition of 2‐aminopurine in double‐ and single‐stranded DNA
Authors: Hardman Samantha J. O. , Thompson Katherine C. 
Published: May 2007

Abstract2‐Aminopurine (2AP) is a widely used marker for nucleic acid structure because the fluorescence of 2AP in double‐stranded DNA is approximately half that of 2AP in single‐stranded DNA. The underlying photophysical mechanism responsible for the change in fluorescence with structure is not understood. We have performed CIS and TDB3LYP level calculations on double‐stranded trinucleotide models, (X2APX)·(YTY), where X and Y represent the natural nucleobases. The results reveal that base stacking combined with hydrogen bonding reduces the oscillator strength for the fluorescence transition, and hence the fluorescence quantum yield. It is also shown that the electronic transitions of double‐stranded trinucleotides are not simply those of the individual bases, but rather involve orbitals that are delocalized across several bases. Although the results obtained at the CIS level suffer from the neglect of electron correlation, the results obtained at the TDB3LYP level are not necessarily better because this method has problems describing long‐range interactions and tends to underestimate the energies of charge‐transfer states. Calculations on a full (rather than model) dinucleotide 5′‐G2AP‐3′ confirm that the inclusion of the sugar and phosphate groups is not necessary when studying the energetically low‐lying excited states of nucleic acids containing 2AP. © 2007 Wiley Periodicals, Inc. Int J Quantum Chem, 2007
Lipid composition of membranes of Escherichia coli by liquid chromatography/tandem mass spectrometry using negative electrospray ionization
Authors: Oursel Delphine , Loutelier‐Bourhis Corinne , Orange Nicole , Chevalier Sylvie , Norris Victor , Lange Catherine M. 
Published: May 2007

AbstractA liquid chromatography/electrospray ionization tandem mass spectrometry (LC/ESI‐MS/MS) method using reversed‐phase chromatography was developed for the analysis of phospholipids from bacterial extracts of a wild‐type strain of Escherichia coli. Product ion mass spectra from [MH]− precursor ions allowed an identification of individual phospholipid species that includes both fatty acid composition and fatty acyl location on the glycerol backbone using diagnostic product ions. Thus, complete assignment, including sn‐1/sn‐2 fatty acyl position, was achieved for this strain of E. coli. In addition, the phospholipids were quantified relative to one another using an internal standard method. Copyright © 2007 John Wiley & Sons, Ltd.
What we learn from the study of ubiquitous processes
Authors: Osterweil Leon J. 
Published: May 2007

AbstractSoftware engineering has come to recognise the value of software processes as vehicles for addressing such goals as improved efficiency in software development, the achievement of improved product quality, and better coordination and communication of the members of software teams. Greater clarity, completeness, and precision in defining these processes seem to lead to greater effectiveness in pursuing these goals. The languages and notations used to support definition of such processes seem to be relatively successful in supporting these definitions, but more progress towards better languages and notations seems indicated. This article suggests that processes are also central to the effective pursuit of essential goals in a broad spectrum of other domains of human endeavour. We suggest that the study of how processes are used in those other domains to pursue goals that are essential in those domains can help us to reflect on our goals for the use of process in software development. Further, we suggest that observing the process language features that seem to facilitate the pursuit of goals in these other domains can similarly suggest features that would seem analogously important in languages used to support the definition of software processes. This article examines the use of processes in domains other than software development and uses observations about these processes to suggest desiderata for software development processes, and the languages used to define them. Copyright © 2007 John Wiley & Sons, Ltd.
Clinical Usefulness of Chest Radiography in Detection of Pulmonary Metastases After Curative Resection for Colorectal Cancer
Authors: Lee Won‐Suk , Yun Seong Hyeon , Chun Ho‐Kyung , Lee Woo Yong , Yun Haeran 
Published: May 2007

AbstractPurposeThe purpose of this study was to evaluate the effectiveness of chest radiography (CXR) and abdominal computed tomography (CT) for detecting pulmonary metastases after curative surgery for colorectal cancer.MethodsWe performed a retrospective analysis of the records of all patients with pulmonary metastasis from colorectal cancer who underwent curative resection between 1994 and 2004 at our institution.ResultsPulmonary metastases were detected in 193 patients by either CXR or abdominal CT. They were initially detected by CXR in 87 patients (45.1%) and by abdominal CT in 106 patients (54.9%). In the CXR group, the patterns of pulmonary recurrence were as follows: solitary (n = 38, 43.7%), multiple unilateral (n = 11, 12.6%), and multiple bilateral (n = 38, 43.7%). In the CT group, there were 22 patients (20.8%) with a solitary nodule, 17 patients (16.0%) with multiple unilateral nodules, and 67 (63.2%) with multiple bilateral nodules. The overall survivals of the CXR group and abdominal CT group were 34.6% and 31.7%, respectively (p = 0.312). There was no difference in the median disease‐free interval between the CXR group and the abdominal CT group (23.8 vs. 23.2 months, p = 0.428).ConclusionsAlthough this study is limited by its small sample size, it can be speculated that abdominal CT with lower thorax images may replace CXR in surveillance programs.
Prolapse severity, symptoms and impact on quality of life among women planning sacrocolpopexy
Authors: FitzGerald M.P. , Janz N.K. , Wren P.A. , Wei J.T. , Weber A.M. , Ghetti C. , Cundiff G.W. ,   for the Pelvic Floor Disorders Network
Published: May 2007

AbstractObjectives: To explore the relationship between severity of pelvic organ prolapse (POP), symptoms of pelvic dysfunction and quality of life using validated measures. Method: Baseline data from 314 participants in the Colpopexy And Urinary Reduction Efforts (CARE) trial were analyzed. Pelvic symptoms and impact were assessed using the Pelvic Floor Distress Inventory (PFDI) and the Pelvic Floor Impact Questionnaire (PFIQ). PFDI and PFIQ scores were compared by prolapse stage and history of incontinence or POP surgery. Regression analyses were performed to identify other predictors of symptoms and impact. Results: Women were predominantly (90%) Caucasian and had mean age of 61 years. Women with stage II POP, especially those with prior surgery, reported more symptoms and impact than women with more advanced POP. There were no other significant predictors of symptoms or life impact. Conclusions: Women planning sacrocolpopexy with stage II prolapse and prior pelvic surgery reported more symptoms and quality of life impact than those with more advanced prolapse.