bluuebunny/crossref_metadata_2025 huggingface dataset:
Detection of Fracture Corridors from Dynamic Data by Factor Analysis
Authors: Ozkaya S. I. , Siyabi S.
Published: August 2008

In this paper, we explore the potential of factor analysis in mapping and modeling fracture corridors using dynamic data in mature fields. Fracture corridors are sub-vertical tabular swarms of fault related conductive fractures which often intersect the entire reservoir, extend laterally for several hundred meters and play major role in reservoir dynamics. Most fracture corridors are too small to be captured by seismic maps. Therefore additional borehole data is needed to map fracture corridors deterministically.

The objective of factor analysis is to discover a few underlying variables which exert control over several observed variables. Measurements of dynamic data in wells, such as productivity Index (PI), gross rates, water cut, Khtest/Khcore ratio, Gas oil ratio (GOR), lost circulation etc. are visible manifestations of underlying factors such as porosity, permeability, mobility ratio, thickness etc. If one of the underlying variables can be identified as fracture corridors, it may be used to identify and map fracture corridors from dynamic data.

Factor analysis was applied in mature carbonate reservoir. The field has a large number of vertical wells with dynamic data and a small number of horizontal wells with borehole image logs. The analysis shows that two factors account for more than 90% of total variation in the observed data from vertical producers. The first factor is correlated with gross rates, water cut rate of rise, mud losses, stepping flow profiles, and injector-producer short cuts. This factor is interpreted as representing fracture corridors. Correlation of mud losses with image logs from horizontal wells confirmed the interpretation which eventually led to successful mapping of fracture corridors in the field from dynamic data.
Effective Water Production Control Through Utilizing ECP and Passive ICD Completion Technologies: Case Histories
Authors: Al-Ahmadi Hasan A. , Al-Mutairi Saad M.
Published: August 2008

Inflow control devices (ICD) have been successfully deployed in Saudi Arabia, in both clastic and carbonate reservoirs, with the objective of creating uniform flow profiles across horizontal wells, delaying early water breakthrough, and preventing water coning and/or gas cusping. The ultimate objective is to increase the oil recovery.

ICDs have been deployed in horizontal wells drilled behind the flood front, in a large carbonate reservoir, in Saudi Arabia. Due to the remaining thin oil column behind the flood front, and their close proximity to injection wells, vertical producers in these areas of the field, normally, produce with high water cut, and consequently die. A campaign was initiated to sidetrack some of these wells and re-complete them horizontally at the top of the reservoir to recover the remaining oil at the top. The reservoir geology is characterized with fractures, which increases the chance for early water breakthrough, since horizontal wells are likely to encounter fractures.

With the utilization of external casing packers (ECP) and ICDs, it has been possible, in most cases, to successfully limit the effect of these loss circulation zones/fractures and enhances well performance. This paper will review some of these wells and will demonstrate the impact and value added resulting from introducing these technologies.
Comparative survival of enteric indicators, E. coli and somatic and F-RNA bacteriophages on turf-grass irrigated with recycled water
Authors: O'Toole J. , Sinclair M. , Diaper C. , Leder K.
Published: August 2008

The aim of this study was to elucidate whether the current withholding period of 4 hours following irrigation of public recreational areas with some classes of recycled water, as prescribed in some Australian state regulations, is valid or whether the holding time can be reduced under specified ambient conditions. A secondary objective was to evaluate laboratory simulations of ambient field conditions for microbial survival experiments. Results suggest that the currently prescribed 4 hour withholding period achieves a reduction of health risk associated with bacterial enteric pathogens that would not otherwise occur if the withholding period was reduced. However, this may not be the case for viral enteric pathogens as the survival of bacteriophages, PRD-1 and MS-2 on turf-grass did not significantly change even after 6 hours, except PRD-1 under high solar conditions. These results suggest that bacteriophages, PRD-1 and MS-2 are more conservative indicators of enteric pathogen survival on UV exposed turf-grass compared with E. coli. The simulations of field conditions in the laboratory were somewhat problematic, with the variations in natural conditions that occur temporally, sometimes for short periods, difficult to reproduce.
Simultaneous bio-reduction of trichloroethene, trichloroethane, and chloroform using a hydrogen-based membrane biofilm reactor
Authors: Chung Jinwook , Rittmann Bruce E.
Published: August 2008

The contamination of water by chlorinated solvents is recognized as a serious and widespread problem throughout the industrialized world. Here, we focus on three chlorinated solvents that are among those most commonly detected and that have distinct chemical features: trichloroethene (TCE), trichloroethane (TCA), and chloroform (CF). Because many contaminated waters contain mixtures of the chlorinated solvents, a treatment technology that detoxifies all of them simultaneously is highly desirable. The membrane biofilm reactor (MBfR) is a recent technological advance that makes it possible to deliver H2 gas to bacteria efficiently and safely, despite hydrogen's low water solubility and risk of forming a combustible atmosphere when mixed with air. The objectives of this work are to document whether or not the three chlorinated compounds can be dechlorinated simultaneously in a H2-based MBfR and to determine if competitive or inhibitory interactions affect bio-reduction of any of the solvents. The main finding is a demonstration that directly using H2 as the electron donor makes it possible to bio-reduce combinations of different chlorinated solvents. This finding supports that the H2-based MBfR can treat multiple chlorinated solvents in one step, addressing a common groundwater situation. We saw possible evidence of inhibition by CF at a concentration greater than about 1 μM, competition for H2 from sulfate and nitrate reductions, and possible inhibition of TCE reduction from the accumulation of chloroethane (CA) or chloromethane (CM).
Use of chitosan for chromium removal from exhausted tanning baths
Authors: Cesaro Raffaele , Fabbricino Massimiliano , Lanzetta Rosa , Mancino Anna , Naviglio Biagio , Parrilli Michelangelo , Sartorio Roberto , Tomaselli Michele , Tortora Gelsomina
Published: August 2008

A novel approach, based on chitosan heavy-metal sequestrating ability, is proposed for chromium(III) removal from spent tanning liquor. Experimental results, obtained at lab-scale using real wastewater, are presented and discussed. Resulting efficiencies are extremely high, and strongly dependent on chitosan dose and pH value. Comparative analyses with other polysaccharides is also carried out showing that amine groups are more efficient than carboxyl and sulphate ones. Chromium recovery from sorption complexes and chitosan regeneration is finally proposed to optimize the whole process.
Removal of EDTA from low pH printed-circuit board wastewater in a fluidized zero valent iron reactor
Authors: Chen Shiao-Shing , Hsu Hong-Der , Lin Yi-Jiun , Chin Pei-Ying
Published: August 2008

Fluidized zero valent iron (ZVI) process was adopted to reduce ethylenediaminetetraacetic acid (EDTA) from low pH printed-circuit board (PCB) wastewater for two reasons: (1) low pH of the wastewater favoring the ZVI reaction; (2) higher ZVI utilization for fluidized process due to abrasive motion of the ZVI. The results showed that the degradation of EDTA was greatly enhanced under acidic pH, longer hydraulic detention time (HRT) and presence of dissolved oxygen (DO). Without addition of oxygen, 65% of EDTA was removed with capacity of 7.33 mg EDTA/g ZVI at pH 2, ZVI dosage of 424 g/L and HRT 10 min. With 6.8 mg/L of DO, 83% of EDTA was reduced with capacity of 19.01 mg EDTA/g ZVI for the same experimental condition. The presence of oxygen/ZVI initiated a Fenton type reaction to reduce EDTA. The end product after EDTA degradation was analyzed by high performance liquid chromoagraphy (HPLC), where propionic acid (C2H5COOH) was observed, indicating EDTA (oxidation number for carbon is 2) was oxidized to propionic acid (oxidation number for carbon is 3). Nitrogen species was also measured and the nitrogen in EDTA was converted to ammonium instead of nitrate and nitrite.
Evaluation of the impact of single-walled carbon nanotubes in an activated sludge wastewater reactor
Authors: Yin Y. , Zhang X.
Published: August 2008

This paper evaluated the impact of single-walled carbon nanotubes (SWCNTs) on the performance and activated sludge properties in an activated sludge wastewater reactor. The reactor was shock loaded with 270 mg/L of 90% purified SWCNTs after the reactor reached quasi-steady state and the reactor was monitored for 18 days after the shock loading. Various experimental parameters were measured and compared. Overall the addition of SWCNTs did not negatively impact the performance of the activated sludge reactor; on the other hand, SWCNTs improved sludge settleability and sludge dewaterability. The cake solids of the sludge were increased and the activated sludge flocs became less negatively charged. The positive impacts were more significant in Phase II (after running the reactor for one solids retention time, SRT) than that in Phase III (after running for additional 1.5 SRT).
Effectiveness of Pulsed Electric Fields in Controlling Microbial Growth in Milk
Authors: Otunola Adedayo , El-Hag Ayman , Jayaram Shesha , Anderson William A
Published: August 2008

A study was conducted to assess the effectiveness of pulsed electric field (PEF) inactivation of a heterogeneous community of microbes. The aim was to assess the impact of process parameters on an indigenous population of microbes present in milk, rather than pure cultures used in other studies. Tests over an electric field strength range of 10  40 kV/cm and 10 to 120 pulses per millilitre showed that high electric field strength and pulse number inactivated microbes by up to approximately 2 log. Inoculum size affected PEF effectiveness when only a few pulses were applied. A significant log-reduction was achieved against the indigenous microbes found in milk that were apparently recalcitrant to commercial pasteurization. Microbial inactivation was more extensive when E. coli was not added to the indigenous population, indicating that the added pure culture was more resistant than the indigenous microbes. The milk fat content had a significant negative effect on the extent of log-reduction for indigenous microbes, when 2% and 18% levels were compared.
Cystatin C, Renal Function and Cardiovascular Risk
Authors: Wagner Carola
Published: August 2008

Cystatin C, Renal Function and Cardiovascular Risk

Cystatin C is a novel serum marker of the glomerular filtration rate (GFR), a critical measure of normal kidney function. Unlike serum creatinine, cystatin C concentrations are independent of gender, age and muscle mass. As cystatin C shown no tubular secretion, it is a much earlier indicator of decreased GFR and allows the detection of mild reductions in GFR, which are not detected by creatinine. Cystatin C has been shown to be associated with future cardiovascular disease and deaths in a dose-dependent relationship that possibly reflects a very early stage of chronic ranal dysfunction. In addition, >sub-clinically< elevated cystatin C concentrations in individuals without chronic kidney disease indicated by creatinine are an independent predictor of progression to chronic kidney disease, heart failure and all-cause mortality.
Synthesis and Biological Evaluation of New Imidazolium and Piperazinium Salts of Pyropheophorbide-a for Photodynamic Cancer Therapy
Authors: Sengee Gerelt-Ireedui , Badraa Narangerel , Shim Young Key
Published: August 2008

We have designed imidazolium and piperazinium salts of pyropheophorbide-a in order to develop effective photosensitizers which have good solubility in polar and non polar media and to reveal the possible influences of the piperazine and imidazole moieties on the biological activities of pyropheophorbide-a. The phototoxicity of those pyropheophorbide-a salts against A549 cells was studied in vitro and compared with that of pyropheophorbide-a. The result showed that complexing piperazine and imidazole into pyropheophorbide-a decreases its dark toxicity without greatly decreasing phototoxicity and, enhances its phototoxicity without greatly increasing dark toxicity, respectively. This work not only describes novel amphiphilic salt complexes of pyropheophobide-a which retain the biological activities of the parent compound pyropheophorbide-a and could be effective candidate for PDT, but also reveals the possibility of developing effective photosensitizers by complexing imidazole and piperazine into other hydrophobic photosensitizers.
Measurement of Electrical Conductivity for a Biomass Fire
Authors: Mphale Kgakgamatso , Heron Mal
Published: August 2008

A controlled fire burner was constructed where various natural vegetation species could be used as fuel. The burner was equipped with thermocouples to measure fuel surface temperature and used as a cavity for microwaves with a laboratory quality 2- port vector network analyzer to determine electrical conductivity from S-parameters. Electrical conductivity for vegetation material flames is important for numerical prediction of flashover in high voltage power transmission faults research. Vegetation fires that burn under high voltage transmission lines reduce flashover voltage by increasing air electrical conductivity and temperature. Analyzer determined electrical conductivity ranged from 0.0058 - 0.0079 mho/m for a fire with a maximum temperature of 1240 K.
Water and Muscle Contraction
Authors: Grazi Enrico
Published: August 2008

The interaction between water and the protein of the contractile machinery as well as the tendency of these proteins to form geometrically ordered structures provide a link between water and muscle contraction. Protein osmotic pressure is strictly related to the chemical potential of the contractile proteins, to the stiffness of muscle structures and to the viscosity of the sliding of the thin over the thick filaments. Muscle power output and the steady rate of contraction are linked by modulating a single parameter, a viscosity coefficient. Muscle operation is characterized by working strokes of much shorter length and much quicker than in the classical model. As a consequence the force delivered and the stiffness attained by attached cross-bridges is much larger than usually believed.
Aflatoxin B1 Degradation by Stenotrophomonas Maltophilia and Other Microbes Selected Using Coumarin Medium
Authors: Guan Shu , Ji Cheng , Zhou Ting , Li Junxia , Ma Qiugang , Niu Tiangui
Published: August 2008

Aflatoxin B1 (AFB1) is one of the most harmful mycotoxins in animal production and food industry. A safe, effective and environmentally sound detoxification method is needed for controlling this toxin. In this study, 65 samples were screened from various sources with vast microbial populations using a newly developed medium containing coumarin as the sole carbon source. Twenty five single-colony bacterial isolates showing AFB1 reduction activity in a liquid culture medium were selected from the screen. Isolate 35-3, obtained from tapir feces and identified to be Stenotrophomonas maltophilia, reduced AFB1 by 82.5% after incubation in the liquid medium at 37 °C for 72 h. The culture supernatant of isolate 35-3 was able to degrade AFB1 effectively, whereas the viable cells and cell extracts were far less effective. Factors influencing AFB1 degradation by the culture supernatant were investigated. Activity was reduced to 60.8% and 63.5% at 20 °C and 30 °C, respectively, from 78.7% at 37 °C. The highest degradation rate was 84.8% at pH 8 and the lowest was only 14.3% at pH 4.0. Ions Mg2+ and Cu2+ were activators for AFB1 degradation, however，ion Zn2+ was a strong inhibitor. Treatments with proteinase K, proteinase K plus SDS and heating significantly reduced or eradicated the degradation activity of the culture supernatant. The results indicated that the degradation of AFB1 by S. maltophilia 35-3 was enzymatic and could have a great potential in industrial applications.
TFIP11, CCNL1 and EWSR1 Protein-protein Interactions, and Their Nuclear Localization
Authors: Tannukit Sissada , Wen Xin , Wang HongJun , Paine Michael L.
Published: August 2008

Previous studies using the yeast two-hybrid assay (Y2H) have identified cyclin L1 (CCNL1) and Ewing sarcoma breakpoint region 1 protein (EWSR1) as being interacting partners of tuftelin-interacting protein 11 (TFIP11). All three proteins are functionally related to the spliceosome and involved in pre-mRNA splicing activities. The spliceosome is a dynamic ribonucleoprotein complex responsible for pre-mRNA splicing of intronic regions, and is composed of five small nuclear RNAs (snRNAs) and ~140 proteins. TFIP11 appears to play a role in spliceosome disassembly allowing for the release of the bound lariat-intron. The roles of CCNL1 and EWSR1 in the spliceosome are poorly understood. Using fluorescently-tagged proteins and confocal microscopy we show that TFIP11, CCNL1 and EWSR1 frequently co-localize to speckled nuclear domains. These data would suggest that all three proteins participate in a common cellular activity related to RNA splicing events.
Isolation and Characterization of Phenolic Compounds from the Leaves of Salix matsudana
Authors: Li Xiang , Liu Zhi , Zhang Xin-feng , Wang Li-juan , Zheng Yi-nan , Yuan Chang-chun , Sun Guang-zhi
Published: August 2008

A bioassay-guided in vitro screen has revealed that a 70% methanol extract of the leaves of Salix matsudana shows considerable inhibitory activity against cyclooxygenases (COX-1 and COX-2). A subsequent phytochemical study led to the isolation of a new flavonoid, matsudone A (1), together with five known flavonoids – luteolin (2), isoquercitrin (3), 7-methoxyflavone (4), luteolin 7-O-glucoside (5), 4',7-dihydroxyflavone (6) – and two phenolic glycosides, leonuriside A (7) and piceoside (8). Their structures were elucidated on the basis of extensive 1D- and 2D-NMR studies, high resolution ESI mass spectroscopic analyses and comparisons with literature data. The isolated compounds 1-8 were tested for their inhibitory activities against COX-1 and COX-2. Compounds 1, 5 and 6 were found to have potent inhibitory effect on COX-2 and compounds 3-5 exhibited moderate inhibition against COX-1.
1,2,5,10,11,14-Hexaoxadispiro[5.2.5.2]hexadecanes: Novel Spirofused Bis-Trioxane Peroxides
Authors: Griesbeck Axel G. , Höinck Lars-Oliver , Lex Johann , Neudörfl Jörg , Blunk Dirk , El-Idreesy Tamer T.
Published: August 2008

A set of new bis-spirofused 1,2,4-trioxanes 4a-d was obtained from the reaction of cyclohexane-1,4-dione with allylic hydroperoxides 2a-d, bearing an additional hydroxy group in the homoallylic position, by diastereoselective photooxygenation of allylic alcohols 1a-d and subsequent BF3-catalyzed peroxyacetalization with the diketone. From the reaction of a monoprotected cyclohexane-1,4-dione 5 with the allylic hydroperoxide 6 derived from the singlet oxygenation of methyl hydroxytiglate, one monospiro compound was obtained, the 1,2,4-trioxane ketone 7, as well as a mixture of the diastereoisomeric syn- and anti bis-1,2,4-trioxanes 8. The structures of bis-1,2,4-trioxanes were examined theoretically by DFT methods and compared with X-ray structural data in order to evaluate the preferential trioxane ring conformational orientation.
Amifostine Protection Against Mitomycin-induced Chromosomal Breakage in Fanconi Anaemia Lymphocytes
Authors: Camelo Ricardo M. , Kehdy Fernanda S. G. , Salas Carlos E. , Lopes Miriam T. P.
Published: August 2008

Fanconi anaemia (FA) is a rare genetic chromosomal instability syndrome caused by impairment of DNA repair and reactive oxygen species (ROS) imbalance. This disease is also related to bone marrow failure and cancer. Treatment of these complications with radiation and alkylating agents may enhance chromosomal breakage. We have evaluated the effect of amifostine (AMF) on basal and mitomycin C (MMC)-induced chromosomal breakage in FA blood cells using the micronucleus assay. The basal micronuclei count was higher among FA patients than healthy subjects. Pre-treatment with AMF significantly inhibited micronucleation induced by MMC in healthy subjects (23.4 ± 4.0 – MMC vs 12.3 ± 2.9 – AMF →MMC) MN/1000CB, p < 0.01, one way ANOVA) as well as in FA patients (80.0 ± 5.8 – MMC vs 40.1 ± 5.8 – AMF →MMC) MN/1000CB, p < 0.01, ANOVA). Release of ROS by peripheral blood mononuclear cells treated with AMF →MMC and measured by chemoluminometry showed that AMF-protection was statistically higher among FA patients than in healthy individuals. Based on these results we suggest that AMF prevents chromosomal breakage induced by MMC, probably by its antioxidant effect.
Trehalose and Trehalose-based Polymers for Environmentally Benign, Biocompatible and Bioactive Materials
Authors: Teramoto Naozumi , Sachinvala Navzer D. , Shibata Mitsuhiro
Published: August 2008

Trehalose is a non-reducing disaccharide that is found in many organisms but not in mammals. This sugar plays important roles in cryptobiosis of selaginella mosses, tardigrades (water bears), and other animals which revive with water from a state of suspended animation induced by desiccation. The interesting properties of trehalose are due to its unique symmetrical low-energy structure, wherein two glucose units are bonded face-to-face by 1→1-glucoside links. The Hayashibara Co. Ltd., is credited for developing an inexpensive, environmentally benign and industrial-scale process for the enzymatic conversion of α-1,4-linked polyhexoses to α,α-D-trehalose, which made it easy to explore novel food, industrial, and medicinal uses for trehalose and its derivatives. Trehalosechemistry is a relatively new and emerging field, and polymers of trehalose derivatives appear environmentally benign, biocompatible, and biodegradable. The discriminating properties of trehalose are attributed to its structure, symmetry, solubility, kinetic and thermodynamic stability and versatility. While syntheses of trehalose-based polymer networks can be straightforward, syntheses and characterization of well defined linear polymers with tailored properties using trehalose-based monomers is challenging, and typically involves protection and deprotection of hydroxyl groups to attain desired structural, morphological, biological, and physical and chemical properties in the resulting products. In this review, we will overview known literature on trehalose’s fascinating involvement in cryptobiology; highlight its applications in many fields; and then discuss methods we used to prepare new trehalose-based monomers and polymers and explain their properties.
Synthesis of RP 48497, an Impurity of Eszopiclone
Authors: Sharov Yu , Zhang Lei , Du Gui-Jie , Ren Jian , Cheng Mao-Sheng
Published: August 2008

RP 48497 is a photodegradation product of eszopiclone, a non-benzodiazepine sedative-hypnotic used in the treatment of insomnia. We report herein the first synthesis of RP 48497 via reduction, chlorination, and recyclization of 6-(5-chloropyridin-2-yl)-7-hydroxy-6,7-dihydropyrrolo[3,4-b]pyrazin-5-one (3), a key intermediate in the synthesis of eszopiclone. The structure of RP 48497 was confirmed by its 1H-NMR and MS data. The mechanism of the reduction step in the synthesis of RP 48497 was also studied and the key parameters were determined. These findings should be important for quality control purposes in the manufacture of eszopiclone.
Synthesis of a Novel D-Glucose-Conjugated 15-Crown-5 Ether with a Spiro Ketal Structure
Authors: Yamanoi Takashi , Oda Yoshiki , Muraishi Hitomi , Matsuda Sho
Published: August 2008

This paper describes a synthetic approach to a novel D-glucose-conjugated 15-crown-5 ether having a spiroketal structure starting from a 1-C-vinylated glucose derivative. The approach consists of the glycosylation of the vinylated glucose derivative to give an ethyleneoxy spacer derivative using bismuth(III) triflate, the conversion of the 1-C-vinyl group of the glucoside produced into a carboxylic acid group, and the intramolecular condensation between the carboxyl group and the terminal hydroxyl group in the ethyleneoxy spacer. A D-glucose-conjugated 15-crown-5 ether having a unique spiroketal structure was thus successfully synthesized.
Water Quality Monitoring for Lake Constance with a Physically Based Algorithm for MERIS Data
Authors: Odermatt Daniel , Heege Thomas , Nieke Jens , Kneubühler Mathias , Itten Klaus
Published: August 2008

A physically based algorithm is used for automatic processing of MERIS level 1B full resolution data. The algorithm is originally used with input variables for optimization with different sensors (i.e. channel recalibration and weighting), aquatic regions (i.e. specific inherent optical properties) or atmospheric conditions (i.e. aerosol models). For operational use, however, a lake-specific parameterization is required, representing an approximation of the spatio-temporal variation in atmospheric and hydrooptic conditions, and accounting for sensor properties. The algorithm performs atmospheric correction with a LUT for at-sensor radiance, and a downhill simplex inversion of chl-a, sm and y from subsurface irradiance reflectance. These outputs are enhanced by a selective filter, which makes use of the retrieval residuals. Regular chl-a sampling measurements by the Lake’s protection authority coinciding with MERIS acquisitions were used for parameterization, training and validation.
Performance and Transient Behavior of Vertically Integrated Thin-film Silicon Sensors
Authors: Wyrsch Nicolas , Choong Gregory , Miazza Clément , Ballif Christophe
Published: August 2008

Vertical integration of amorphous hydrogenated silicon diodes on CMOS readout chips offers several advantages compared to standard CMOS imagers in terms of sensitivity, dynamic range and dark current while at the same time introducing some undesired transient effects leading to image lag. Performance of such sensors is here reported and their transient behaviour is analysed and compared to the one of corresponding amorphous silicon test diodes deposited on glass. The measurements are further compared to simulations for a deeper investigation. The long time constant observed in dark or photocurrent decay is found to be rather independent of the density of defects present in the intrinsic layer of the amorphous silicon diode.
Antibody Fragments as Probe in Biosensor Development
Authors: Saerens Dirk , Huang Lieven , Bonroy Kristien , Muyldermans Serge
Published: August 2008

Today’s proteomic analyses are generating increasing numbers of biomarkers, making it essential to possess highly specific probes able to recognize those targets. Antibodies are considered to be the first choice as molecular recognition units due to their target specificity and affinity, which make them excellent probes in biosensor development. However several problems such as difficult directional immobilization, unstable behavior, loss of specificity and steric hindrance, may arise from using these large molecules. Luckily, protein engineering techniques offer designed antibody formats suitable for biomarker analysis. Minimization strategies of antibodies into Fab fragments, scFv or even single-domain antibody fragments like VH, VL or VHHs are reviewed. Not only the size of the probe but also other issues like choice of immobilization tag, type of solid support and probe stability are of critical importance in assay development for biosensing. In this respect, multiple approaches to specifically orient and couple antibody fragments in a generic one-step procedure directly on a biosensor substrate are discussed.
Feature Reduction in Graph Analysis
Authors: Piriyakul Rapepun , Piamsa-nga Punpiti
Published: August 2008

A common approach to improve medical image classification is to add more features to the classifiers; however, this increases the time required for preprocessing raw data and training the classifiers, and the increase in features is not always beneficial. The number of commonly used features in the literature for training of image feature classifiers is over 50. Existing algorithms for selecting a subset of available features for image analysis fail to adequately eliminate redundant features. This paper presents a new selection algorithm based on graph analysis of interactions among features and between features to classifier decision. A modification of path analysis is done by applying regression analysis, multiple logistic and posterior Bayesian inference in order to eliminate features that provide the same contributions. A database of 113 mammograms from the Mammographic Image Analysis Society was used in the experiments. Tested on two classifiers – ANN and logistic regression – cancer detection accuracy (true positive and false-positive rates) using a 13-feature set selected by our algorithm yielded substantially similar accuracy as using a 26-feature set selected by SFS and results using all 50-features. However, the 13-feature greatly reduced the amount of computation needed.
CO2 Selective Potentiometric Sensor in Thick-film Technology
Authors: Sahner Kathy , Schulz Anne , Kita Jaroslaw , Merkle Rotraut , Maier Joachim , Moos Ralf
Published: August 2008

A potentiometric sensor device based on screen-printed Nasicon films was investigated. In order to transfer the promising sensor concept of an open sodium titanate reference to thick film technology, “sodium-rich” and “sodium-poor” formulations were compared. While the “sodium-rich” composition was found to react with the ion conducting Nasicon during thermal treatment, the “sodium-poor” reference mixture was identified as an appropriate reference composition. Screen-printed sensor devices were prepared and tested with respect to CO2 response, reproducibility, and cross-interference of oxygen. Excellent agreement with the theory was observed. With the integration of a screen-printed heater, sensor elements were operated actively heated in a cold gas stream.
A Fast Inspection of Tool Electrode and Drilling Depth in EDM Drilling by Detection Line Algorithm
Authors: Huang Kuo-Yi
Published: August 2008

The purpose of this study was to develop a novel measurement method using a machine vision system. Besides using image processing techniques, the proposed system employs a detection line algorithm that detects the tool electrode length and drilling depth of a workpiece accurately and effectively. Different boundaries of areas on the tool electrode are defined: a baseline between base and normal areas, a ND-line between normal and drilling areas (accumulating carbon area), and a DD-line between drilling area and dielectric fluid droplet on the electrode tip. Accordingly, image processing techniques are employed to extract a tool electrode image, and the centroid, eigenvector, and principle axis of the tool electrode are determined. The developed detection line algorithm (DLA) is then used to detect the baseline, ND-line, and DD-line along the direction of the principle axis. Finally, the tool electrode length and drilling depth of the workpiece are estimated via detected baseline, ND-line, and DD-line. Experimental results show good accuracy and efficiency in estimation of the tool electrode length and drilling depth under different conditions. Hence, this research may provide a reference for industrial application in EDM drilling measurement.
Estimation of Phytoplankton Responses to Hurricane Gonu over the Arabian Sea Based on Ocean Color Data
Authors: Wang Dongxiao , Zhao Hui
Published: August 2008

In this study the authors investigated phytoplankton variations in the Arabian Sea associated with Hurricane Gonu using remote-sensing data of chlorophyll-a (Chl-a), sea surface temperature (SST) and winds. Additional data sets used for the study included the hurricane and Conductivity-Temperature-Depth data. Hurricane Gonu, presenting extremely powerful wind intensity, originated over the central Arabian Sea (near 67.7ºE, 15.1ºN) on June 2, 2007; it traveled along a northwestward direction and made landfall in Iran around June 7. Before Hurricane Gonu, Chl-a data indicated relatively low phytoplankton biomass (0.05-0.2 mg m-3), along with generally high SST (>28.5 ºC) and weak wind (
A Polypyrrole-based Strain Sensor Dedicated to Measure Bladder Volume in Patients with Urinary Dysfunction
Authors: Rajagopalan Sumitra , Sawan Mohamad , Ghafar-Zadeh Ebrahim , Savadogo Oumarou , Chodavarapu Vamsy P.
Published: August 2008

This paper describes a new technique to measure urine volume in patients with urinary bladder dysfunction. Polypyrrole – an electronically conducting polymer - is chemically deposited on a highly elastic fabric. This fabric, when placed around a phantom bladder, produced a reproducible change in electrical resistance on stretching. The resistance response to stretching is linear in 20%-40% strain variation. This change in resistance is influenced by chemical fabrication conditions. We also demonstrate the dynamic mechanical testing of the patterned polypyrrole on fabric in order to show the feasibility of passive interrogation of the strain sensor for biomedical sensing applications.
Electrocatalytic Detection of Amitrole on the Multi-Walled Carbon Nanotube – Iron (II) tetra-aminophthalocyanine Platform
Authors: Siswana Msimelelo , Ozoemena Kenneth I. , Nyokong Tebello
Published: August 2008

It is shown that iron(II) tetra-aminophthalocyanine complex electropolymerized onto a multi-walled carbon nanotube-modified basal plane pyrolytic graphite electrode greatly enhanced the electrocatalytic detetion of amitrole (a toxic herbicide), resulting in a very low detection limit (0.5 nM) and excellent sensitivity of 8.80±0.44 μA/nM, compared to any known work reported so far. The electrocatalytic detection of amitrole at this electrode occurred at less positive potential (~0.3 V vs Ag|ACl) and also revealed a typical coupled chemical reaction. The mechanism for this response is proposed. The electrode gave satisfactory selectivity to amitrole in the presence of other potential interfering pesticides in aqueous solutions.
A Novel Nonenzymatic Hydrogen Peroxide Sensor Based on a Polypyrrole Nanowire-Copper Nanocomposite Modified Gold Electrode
Authors: Zhang Tingting , Yuan Ruo , Chai Yaqin. , Li Wenjuan , Ling Shujuan
Published: August 2008

A novel nonenzymatic hydrogen peroxide (H2O2) sensor has been fabricated by dispersing copper nanoparticles onto polypyrrole (PPy) nanowires by cyclic voltammetry (CV) to form PPy-copper nanocomposites on gold electrodes. Scanning electron microscopy (SEM) was used to characterize the morphologies of the PPy nanowires and the PPy-copper nanocomposite. The reactivity of the PPy-copper nanocomposite towards H2O2 was characterized by cyclic voltammetry and chronoamperometry. Effects of applied potential, the concentrations of detection solution upon the response currents of the sensor were investigated for an optimum analytical performance. It was proved that the PPy-copper nanocomposite showed excellent catalytic activity for the reduction of hydrogen peroxide (H2O2). The sensor showed a linear response to hydrogen peroxide in the concentration range between 7.0×10-6 and 4.3×10-3 mol L-1 with a high sensitivity, and a detection limit of 2.3×10-6 mol L-1. Experiment results also showed that the sensor had good stability.
Limits to Nanopatterning of Fluids on Surfaces in Soft Lithography
Authors: Wigenius Jens A. , Hamedi Mahiar , Inganäs Olle
Published: August 2008

Soft lithographic microcontact printing using the residual polydimethylsiloxane (PDMS) found in elastomeric PDMS stamps is demonstrated to lead to unstable prints with sub‐micrometer dimensions. The statics and dynamics of the process have been followed with time‐resolved atomic force microscopy, imaging ellipsometry, water contact angle measurement, and optical diffraction. It is proposed that this instability places a fundamental limitation on patterning by macromolecular fluids, which is of general relevance to soft lithography and nanoimprint lithography with low viscosity polymers.
SERS Aptatags: New Responsive Metallic Nanostructures for Heterogeneous Protein Detection by Surface Enhanced Raman Spectroscopy
Authors: Fabris Laura , Dante Mark , Nguyen Thuc‐Quyen , Tok Jeffrey B.‐H. , Bazan Guillermo C.
Published: August 2008

We report here “aptatags,” which consist of aptamer‐modified silver nanoparticles (NPs) held together by an optical reporter. It is possible to use these materials to design a heterogeneous method for protein identification that takes advantage of the Raman signal enhancement by metallic nanostructures and the recognition capabilities of aptamers. Aptatags are formed by linking silver NPs with an organic dithiol molecule, followed by surface modification with thiolated single‐stranded DNA (ssDNA) corresponding to the sequence of the aptamer probe. The sensing surface involves a silver layer containing the thiolated capturing aptamer and mercaptohexadecanoic acid to minimize nonspecific binding. The overall process provides excellent selectivity and sensitivity. Detailed characterization of the sensing surface by SERS maps and atomic force microscopy was carried out to understand how structural features lead to signal generation.
Toxicity and the cardiovascular activity of organotin compounds: a review
Authors: Nath Mala
Published: August 2008

A comprehensive review on toxicity of organotin compounds including sources of their intake and mode of action, and cardiovascular activity of organotin compounds is presented. Further research to develop novel useful organotin compounds having hypertensive activity needs to be carried out. Copyright © 2008 John Wiley & Sons, Ltd.
Synthesis and application of bimetallic chiral [Co(salen)]‐type complexes: a new catalytic approach to synthesis of optically pure β‐blockers via kinetic resolution of epichlorohydrin
Authors: Kawthekar Rahul B. , Bi Wen‐tao , Kim Geon‐Joong
Published: August 2008

A series of bimetallic chiral [Co(salen)]‐type complexes were successfully applied for the synthesis of optically pure β‐blockers via phenolic kinetic resolution (PKR) of racemic epichlorohydrin [2‐(chloromethyl)oxirane; ( ± )ECH]. The reaction proceeded readily at room temperature and consequently provided enantiomerically enriched corresponding α‐aryloxy alcohols with excellent enantioselectivities of up to 98% ee. The PKR method described in this work is highly efficient and straightforward strategy for the synthesis of chiral building blocks. Copyright © 2008 John Wiley & Sons, Ltd.
Synthesis and characterization of heterotelechelic poly(ethylene glycol)s with amino acid at one end and hydroxyl group at another end
Authors: Zhang Jing , Su Zhi‐Guo , Ma Guang‐Hui
Published: August 2008

Heterotelechelic poly(ethylene glycol)s are widely used in the modification, conjugation, and crosslinking of biomacromolecules. A series of heterotelechelic PEGs with amino acid at one end and hydroxyl group at another end, including α‐glycine‐ω‐hydroxyl‐PEG, α‐proline‐ω‐hydroxyl‐PEG, and α‐phenylalanine‐ω‐hydroxyl‐PEG, were first synthesized in this study. The reaction proceeded at ambient temperature under alkaline conditions via an aqueous solution polymerization of ethylene oxide. Amino group of glycine, proline, and phenylalanine was the initiating center in the polymerizations, and carboxyl group of these amino acids was reserved as one of the active end groups of the obtained heterotelechelic PEG. Purification of the desired products was accomplished by silica gel column chromatography. The obtained heterotelechelic PEGs were characterized by means of FT‐IR, 1H NMR, 13C NMR, MS, and RP‐HPLC. They were in different forms depending on the type of initiating amino acid, e.g. α‐glycine‐ω‐hydroxyl‐PEG and α‐phenylalanine‐ω‐hydroxyl‐PEG are in branched form, and α‐proline‐ω‐hydroxyl‐PEG is linear. Amino acids were conjugated to PEG chains through the stable carbon–nitrogen bond. Compared with the traditional critical polymerization conditions, the advantage of this method is that various amino acid ended heterotelechelic PEGs can be designed and obtained by using different amino acid as the initiator through a much more convenient route, which proceeded in aqueous solution at ambient temperature. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Morphologies and mechanical properties of HDPE induced by small amount of high‐molecular‐weight polyolefin and shear stress produced by dynamic packing injection molding
Authors: Chen Zhanchun , Lei Jun , Gao Xueqin , Deng Cong , Gao Lei , Shen Kaizhi
Published: August 2008

To better understand the effect of a small amount of high‐molecular‐weight polyethylene (HMWPE) on the mechanical properties and crystal morphology under the shear stress field, the dynamic packing injection molding (DPIM) was used to prepare the oriented pure polyethylene and its blends with 4% HMWPE. The experiment substantiated that the further improvement of tensile strength along the flow direction (MD) of high‐density polyethylene (HDPE)/HMWPE samples was achieved, whereas the tensile strength along the transverse direction (TD) still substantially exceeded that of conventional molding. Tensile strength in both flow and TDs were highly enhanced, with improvements from 23 to 76 MPa in MD and from 23 to 31 MPa in TD, besides the toughness was highly improved. So, the samples of HDPE/HMWPE transformed from high strength and brittleness to high strength and toughness. The obtained samples were characterized via SEM and TEM. For HDPE/HMWPE, the lamellae of the one shish‐kebab in the oriented region may be stretched into other shish‐kebab structures, and one lamella enjoys two shish or even more. This unique crystal morphology could lead to no yielding and necking phenomena in the stress–strain curves of HDPE/HMWPE samples by DPIM. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Preparation of a natural rubber core/polymer shell in a nanomatrix by graft copolymerization
Authors: Arayapranee Wanvimon , Rempel Garry L.
Published: August 2008

The grafting of a vinyl monomer, methyl methacrylate (MMA) or styrene (ST), onto a natural rubber (NR) exhibited a core–shell structure, with NR as the core and poly(methyl methacrylate) or polystyrene as the shell. The grafting efficiency (GE) of the graft copolymer was determined by a solvent‐extraction technique. The synthesized graft copolymer was purified and then characterized by Fourier transform infrared spectroscopy analysis. The effects of the graft parameters, including time, initiator content, and concentration, and the type of monomer, MMA or ST, were investigated. A longer time was favorable for the graft copolymerization. GE first increased and then decreased with increasing concentration of initiator. GE decreased with increasing monomer content, and it was confirmed that the graft copolymerization was a surface‐controlled process. The grafting ST monomer had a higher GE compared to MMA under the same conditions. The characterization of the particles by transmission electron microscopy and scanning electron microscopy confirmed the formation of a core–shell structure. From the micrographs, we inferred that at 71% GE, the NR seed particle had a complete closed shell several nanometers in thickness. Therefore, the NR particle was dispersed in a polymer nanomatrix. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
CYP17 Inhibitors. Annulations of Additional Rings in Methylene Imidazole Substituted Biphenyls: Synthesis, Biological Evaluation and Molecular Modelling
Authors: Pinto‐Bazurco Mendieta Mariano A. E. , Negri Matthias , Hu Qingzhong , Hille Ulrike E. , Jagusch Carsten , Jahn‐Hoffmann Kerstin , Müller‐Vieira Ursula , Schmidt Dirk , Lauterbach Thomas , Hartmann Rolf W.
Published: August 2008

Twenty‐one novel compounds originating from two classes of annulated biphenyls were synthesized as mimetics of the steroidal A‐ and C‐rings and examined for their potency as inhibitors of human CYP17. Selected compounds were tested for inhibition of the hepatic CYP enzyme 3A4. Potent CYP17 inhibitors were found for each class, compound 9 (17 and 71% at 0.2 and 2 μM, respectively) and 21 (591 nM). Compound 21 showed only weak inhibition of CYP3A4 (32 and 64% at 2 and 10 μM, respectively). Both compounds, however, exhibited moderate to strong inhibition of the glucocorticoid‐forming enzyme CYP11B1. The most interesting compounds were docked into our protein model. They bound into one of the modes which we have previously published. New interaction regions were identified.
Synthesis and Antiprotozoal Evaluation of New N4‐(Benzyl)spermidyl‐linked bis(1,3,5‐thiadiazinane‐2‐thiones)
Authors: Coro Julieta , Little Susan , Yardley Vanessa , Suárez Margarita , Rodríguez Hortensia , Martín Nazario , Perez‐Pineiro Rolando
Published: August 2008

The synthesis and in‐vitro antiprotozoal evaluation of novel N4‐(benzyl)spermidyl‐linked bis(1,3,5‐thiadiazinane‐2‐thione) (bis‐THTT) derivatives from N4‐(benzyl)spermidine is disclosed. Several of the new bis‐THTT have in‐vitro activities against L. donovani and T. cruzi that are comparable or superior to those of currently employed protozoocidal agents.
Information resources in High‐Energy Physics: Surveying the present landscape and charting the future course
Authors: Gentil‐Beccot Anne , Mele Salvatore , Holtkamp Annette , O'Connell Heath B. , Brooks Travis C.
Published: August 2008

Access to previous results is of paramount importance in the scientific process. Recent progress in information management focuses on building e‐infrastructures for the optimization of the research workflow, through both policy‐driven and user‐pulled dynamics. For decades, High Energy Physics (HEP) has pioneered innovative solutions in the field of information management and dissemination. In light of a transforming information environment, it is important to assess the current usage of information resources by researchers and HEP provides a unique test bed for this assessment. A survey of about 10% of practitioners in the field reveals usage trends and information needs. Community‐based services, such as the pioneering arXiv and SPIRES systems, largely answer the need of the scientists, with a limited but increasing fraction of younger users relying on Google. Commercial services offered by publishers or database vendors are essentially unused in the field. The survey offers an insight into the most important features that users require to optimize their research workflow. These results inform the future evolution of information management in HEP and, as these researchers are traditionally “early adopters” of innovation in scholarly communication, can inspire developments of disciplinary repositories serving other communities.
Investigations of a simulated geomagnetic field experienced by the international space station on attentional performance
Authors: Del Seppia Cristina , Mezzasalma Lorena , Messerotti Mauro , Cordelli Alessandro , Ghione Sergio
Published: August 2008

We have previously reported that the exposure to an abnormal magnetic field simulating the one encountered by the International Space Station (ISS) orbiting around the Earth may enhance autonomic response to emotional stimuli. Here we report the results of the second part of that study which tested whether this field also affects cognitive functions. Twenty‐four volunteers participated in the study, 12 exposed to the natural geomagnetic field and 12 to the magnetic field encountered by ISS. The test protocol consisted of a set of eight tests chosen from a computerized test battery for the assessment of attentional performance. The duration of exposure was 90 min. No effect of exposure to ISS magnetic field was observed on attentional performance. Bioelectromagnetics 30:45–51, 2009. © 2008 Wiley‐Liss, Inc.