bluuebunny/crossref_metadata_2025_split huggingface dataset:
Removal and Recovery of UO2(??) from Water Samples Using 2,2′‐Diamino‐4,4′‐bithiazole as a New Reagent for Solid Phase Extraction
Authors: Soleimani Majid , Khani Azam 
Published: April 2010

AbstractA novel sensitive and simple method for rapid and selective extraction, preconcentration and determination of uranyl as its 2,2′‐diamino‐4,4′‐bithiazole (DABTZ) complex by using octadecylsilica columns and spectrophotometry is presented. Extraction efficiency and the influence of flow rates of sample solution and eluent, pH, amount of DABTZ, type and least amount of eluent for elution of uranyl complex from columns, break‐through volume and limit of detection were evaluated. Also the effects of various cationic and anionic interferences on percent recovery of uranyl were studied. Average extraction efficiency of ca. 90% was obtained by elution of the column with minimal amount of solvent in the presence of interferences. The average preconcentration factor, 136 and a detection limit 0.32 ng·mL−1 were obtained. The method was applied to the recovery and determination of uranyl in different water samples.
Allylation of Carbonyl Compounds Mediated by Aluminum/Fluoride Salts in Water
Authors: Yuan Shizhen , Liu Jin , Xu Ling , Zhu Shaofeng 
Published: April 2010

AbstractA novel mediator (Al/KF) has been developed and employed in the Barbier‐type alkylations of various aldehydes and ketones with alkyl halide in water. The carbonyl compounds could be effectively converted into corresponding homoallylic alcohol in good yields only when allyl bromides or substituted allyl bromides were used as halides. Aromatic aldehydes could afford homoallylic alcohols in high yields, unfortunately, the allylation of aromatic aldehyde substituted by nitro‐ or amino‐group could not proceed smoothly, and the allylation yields of ketones and aliphatic carbonyl compounds were lower under the same condition. The diastereoselectivity and regioseletivity of the reaction have also been studied, the predominant products preferred the erythro‐ or anti‐isomer in dominant γ‐adduct by using Al/KF mediated allylation of benzaldehydes with cinnamyl bromide and ethyl 4‐bromo‐2‐butenoate in water.
Synthesis of Biologically Active [4‐(4‐Bromophenyl)‐2‐thiazolyl]hydrazones and their D‐Galactose Derivatives
Authors: Ramadan El Sayed 
Published: April 2010

AbstractBenzaldehyde [4‐(4‐bromophenyl)thiazol‐2‐yl]hydrazones 5a–5d were prepared by reacting the thiosemicarbazones 2a–2d with 2,4′‐dibromoacetophenone (1) in absolute ethanol. Acetylation of 5a and 5b with Ac2O/Py at room temperature gave the N‐acetyl derivatives 6a and 6b. 4‐Methyl‐2‐pentanone/cyclopentanone [4‐(4‐bromo‐phenyl)thiazol‐2‐yl]hydrazones (8a) and (8b) were similarly obtained from the reaction of 1 with the thiosemicarbazones 7a and 7b, respectively. Cyclization of D‐galactose thiosemicarbazone (9) and its tautomers 10 and 11 with 1 afforded an equilibrium mixture of the acyclic 2‐thiazolylhydrazone 12, together with its respective cyclic galactosyl derivatives 13 and 14, whose structures were studied by using 1H and 13C NMR spectra. The antimicrobial activity of the synthesized thiazole derivatives was evaluated in vitro by using an agar diffusion technique, and some of these compounds showed potential activity against Candida albicans.
Enantioselective Aldol Reaction of α‐Ketoester and Cyclopentaone Catalyzed by L‐Proline
Authors: Xiang Jiming , Li Baolin 
Published: April 2010

AbstractA concise and enantioselective synthesis of (S)‐ethyl 2‐cyclopentyl‐2‐hydroxy‐2‐arylacetate, a key intermediate for the muscarinic receptor, is reported. The tertiary stereogenic center was constructed with good stereoselectivity through the L‐proline‐catalyzed direct asymmetric aldol reaction of ethyl arylglyoxylate and cyclopentanone. The carbonyl of the condensation product was reduced using a modified Clemmensen reaction which provided an easier workup and was more environmentally acceptable. The enantioselectivity of the aldol reactions was between 58.3%–93.2%, which means that the stereoselective is efficient in controlling configuration of reaction product.
Cholesterol‐substituted Tetrathiafulvalene (TTF) Compound: Formation of Organogel and Supramolecular Chirality
Authors: Wang Cheng , Sun Fei , Zhang Deqing , Zhang Guanxin , Zhu Daoben 
Published: April 2010

AbstractA new tetrathiafulvalene (TTF) derivative with two cholesterol units (compound 1) was synthesized and characterized. Gelation of n‐hexane occurred after the hot solution of 1 was subjected to ultrasonic treatment for a few minutes. The resulting organogel was characterized with SEM, XRD and AFM. Besides heating the gel‐sol transition also occurred upon addition of I2 which can oxidize the TTF unit in 1. This result provides a new example of organogels responding to redox reactions. Interestingly, gelation‐induced CD signals were observed and the CD signals can be tuned with the gel‐sol transition which can be effected by heating and chemical reaction with I2.
Coupling Proteins to Amine‐terminated Magnetic Particles Activated with 1,4‐Phenylene Diisothiocyanate
Authors: Tang Yitong , Geng Tingting , Xin Xiaofang , Chen Chao , Cui Yali 
Published: April 2010

AbstractThe homobifunctional crosslinker 1,4‐phenylene diisothiocyanate (PDC) was coupled to amine‐terminated magnetic particles, and human IgG, streptavidin, protein G and protein A were immobilized on the activated magnetic particles. The coupling of PDC to the amine‐terminated magnetic particles was completed in 10 min, and 1 mg of activated magnetic particles was able to immobilize 95 (g of protein G, 120 µg of protein A, 160 µg of streptavidin and 280 µg of IgG. Ultraviolet‐visible spectroscopy, FTIR spectroscopy and electron micrography were used to characterize the functional particles. The results indicated that PDC was successfully coupled to the surface of the amine‐terminated magnetic particles, and the proteins were effectively immobilized on their surface. The activity of protein G immobilized on the activated magnetic particles was confirmed by its ability to purify IgG from plasma.
Dependence of Property of Silver Nanoparticles within Dendrimer‐template on Molar Ratios of Ag+ to PAMAM Dendrimers
Authors: Li Guoping , Luo Yunjun , Lu Wenting , Li Jie , Jin Yujuan , Guo Sufang 
Published: April 2010

AbstractG5.0‐OH PAMAM dendrimers were used to prepare fluorescent silver clusters with weaker ultraviolet irradiation reduction method, in which the molar ratio of Ag+ to PAMAM dendrimers was the key factor to determine the geometry and properties of silver nanoparticles. The results showed that because of G5.0‐OH PAMAM dendrimers as strong encapsulatores, when the molar ratios of Ag+ to PAMAM dendrimers was smaller than 5, the obtained Agn clusters (n<5) had line structures and "molecular‐like" properties, which were highly fluorescent and quite stable in aqueous solution. Whereas when the molar ratios were between 5 and 8, the obtained Agn clusters were 2D structures and their fluorescence was weaker. When the molar ratio was larger than 8, the structure of silver nanoparticles was 3D and no fluorescence was observed from the obtained silver nanoparticles.
hytic Acid Conversion Coatings of Magnesium
Authors: Liu Jianrui , Guo Yina , Huang Weidong 
Published: April 2010

AbstractA chrome‐free conversion coating treatment for magnesium by phytic acid solution was developed. The immersion experiments were used for evaluating the effects of the processing parameters (such as conversion temperature and time, concentration and pH value of phytic acid solution) on the corrosion resistance of the phytic acid conversion coating. The morphologies and compositions of the coatings were determined by SEM and EDS respectively. The experimental results indicated that the corrosion resistance of the conversion coating formed in the solution containing 0.5% phytic acid at 25°C and pH=4 for 30 min was higher than that of natural oxide, and the conversion coating formed on the surface of magnesium was of multilayer mainly consisting of Mg, C, O and P. The thicknesses of the conversion coatings were approximately 1.0–15 µm and the conversion coatings presented obvious network‐like cracks. The electrochemical potentiodynamic polarization experiment indicated that the free corrosion potential of the magnesium with phytic acid conversion coating was increased, and its corrosion current and corrosion rate declined in 3.5% NaCl solution. Phytic acid conversion coating could improve the electrochemical property of magnesium and provide effective protection, which can improve the corrosion resistance of magnesium.
Solid‐Phase Extraction of Metoprolol onto (Methacrylic acid‐ ethylene glycol dimethacrylate)‐based Molecularly Imprinted Polymer and Its Spectrophotometric Determination
Authors: Saber Tehrani Mohammad , Vardini Mohammad Taghi , Abroomand Azar Parviz , Husain Syed Waqif 
Published: April 2010

AbstractA new adsorbent for molecularly imprinted solid phase extraction (MISPE) of metoprolol was synthesized using methacrylic acid (MAA) as functional monomer and ethylene glycol dimethacrylate (EGDMA) as cross‐linking agent causing a non‐covalent, bulk, thermal radical‐polymerization. Control polymer (non‐imprinted polymer) was prepared under well defined conditions without the use of metoprolol. The synthesized polymers were characterized by IR spectroscopy, X‐ray diffraction and thermal analysis techniques. This polymer was used for the rapid extraction and preconcentration of metoprolol from real samples prior to spectrophotometric determination. Extraction efficiency and the influence of flow rates of sample and stripping solutions, pH, type of eluent for elution of metoprolol from polymer, break through volume and limit of detection were studied. The detection limit of the proposed method is 0.4 ng·mL−1. The method was applied successfully to the recovery and determination of metoprolol in tablets, human urine and plasma samples.
Silica‐bonded S‐Sulfonic Acid: A Recyclable Catalyst for the Synthesis of Trisubstituted Imidazoles under Solvent‐free Conditions
Authors: Niknam Khodabakhsh , Mohammadizadeh Mohammad R. , Mirzaee Salimeh , Saberi Dariush 
Published: April 2010

AbstractTrisubstituted imidazoles have been synthesized in high yields in the presence of silica‐bonded S‐sulfonic acid as a catalyst. The reaction was carried out at 130°C under solvent‐free conditions. The reaction work‐up is simple and the catalyst is easily separated from the products by filtration.
The Binding Mode of Side Chain‐ and C3‐Modified Epothilones to Tubulin
Authors: Erdélyi Máté , Navarro‐Vázquez Armando , Pfeiffer Bernhard , Kuzniewski Christian N. , Felser Andrea , Widmer Toni , Gertsch Jürg , Pera Benet , Díaz José Fernando , Altmann Karl‐Heinz , Carlomagno Teresa 
Published: April 2010

AbstractThe tubulin‐binding mode of C3‐ and C15‐modified analogues of epothilone A (Epo A) was determined by NMR spectroscopy and computational methods and compared with the existing structural models of tubulin‐bound natural Epo A. Only minor differences were observed in the conformation of the macrocycle between Epo A and the C3‐modified analogues investigated. In particular, 3‐deoxy‐ (compound 2) and 3‐deoxy‐2,3‐didehydro‐Epo A (3) were found to adopt similar conformations in the tubulin‐binding cleft as Epo A, thus indicating that the 3‐OH group is not essential for epothilones to assume their bioactive conformation. None of the available models of the tubulin–epothilone complex is able to fully recapitulate the differences in tubulin‐polymerizing activity and microtubule‐binding affinity between C20‐modified epothilones 6 (C20‐propyl), 7 (C20‐butyl), and 8 (C20‐hydroxypropyl). Based on the results of transferred NOE experiments in the presence of tubulin, the isomeric C15 quinoline‐based Epo B analogues 4 and 5 show very similar orientations of the side chain, irrespective of the position of the nitrogen atom in the quinoline ring. The quinoline side chain stacks on the imidazole moiety of β‐His227 with equal efficiency in both cases, thus suggesting that the aromatic side chain moiety in epothilones contributes to tubulin binding through strong van der Waals interactions with the protein rather than hydrogen bonding involving the heteroaromatic nitrogen atom. These conclusions are in line with existing tubulin polymerization and microtubule‐binding data for 4, 5, and Epo B.
Prognostic value of mucin 4 expression in colorectal adenocarcinomas
Authors: Shanmugam Chandrakumar , Jhala Nirag C. , Katkoori Venkat R. , Wan Wen , Meleth Sreelatha , Grizzle William E. , Manne Upender 
Published: April 2010

AbstractBACKGROUND:Mucin 4 (MUC4) is aberrantly expressed in colorectal adenocarcinomas (CRCs) but its prognostic value is unknown.METHODS:Archival tissue specimens collected from 132 CRC patients who underwent surgical resection without presurgery or postsurgery therapy were evaluated for expression of MUC4 by using a mouse monoclonal antibody and horseradish peroxidase. MUC4 expression levels were correlated with clinicopathologic features and patient survival. Survival was estimated by both univariate Kaplan‐Meier and multivariate Cox regression methods.RESULTS:In both normal colonic epithelium and CRCs, MUC4 staining was localized primarily in the cytoplasm. The optimal immunostaining cutoff value (≥75% positive cells and an immunostaining score ≥2.0), which was derived by using the bootstrap method, was used to categorize CRCs into groups of high expression (33 of 132 patients; 25%) or low expression (99 of 132 patients; 75%). Patients who had early stage tumors (stages I and II) with high MUC4 expression had a shorter disease‐specific survival (log‐rank;P= .007) than patients who had with low expression. Patients who had advanced‐stage CRCs (stages III and IV) did not demonstrate such a difference (log‐rank;P= .108). Multivariate regression models that were generated separately for patients with early stage and advanced‐stage CRC confirmed that increased expression of MUC4 was an independent indicator of a poor prognosis only for patients who had early stage CRCs (hazard ratio, 3.77; 95% confidence interval, 1.46‐9.73).CONCLUSIONS:The current results indicated that increased MUC4 expression is a predictor of poor survival in CRC, specifically for patients who have early stage tumors. Cancer 2010. © 2010 American Cancer Society.
A phase 1‐2 study of imexon plus dacarbazine in patients with unresectable metastatic melanoma
Authors: Weber Jeffrey S. , Samlowski Wolfram E. , Gonzalez Rene , Ribas Antoni , Stephenson Joe , O'Day Steven , Sato Takami , Dorr Robert , Grenier Kathryn , Hersh Evan 
Published: April 2010

AbstractBACKGROUND:Imexon (Amplimexon) is an aziridine compound that increases reactive oxygen species, disrupts mitochondrial membranes, and induces apoptosis. Preclinical studies showed activity against melanoma cell lines and models in mice, and synergy with dacarbazine. The authors evaluated standard doses of dacarbazine combined with increasing doses of imexon to determine the maximal tolerated dose (MTD), toxicities, pharmacokinetics, and efficacy.METHODS:Sixty‐eight chemotherapy‐naive melanoma patients (1 inoperable stage III and 67 stage IV) were treated with dacarbazine (250 mg/m2) and imexon (570‐1300 mg/m2), both daily for 5 days every 3 weeks.RESULTS:There were 18 patients in the phase 1, and 50 in the phase 2 component of the study. The MTD of imexon with dacarbazine was 1000 mg/m2. Dose‐limiting toxicities were pulmonary edema and hepatorenal failure. At the MTD, therapy was well tolerated. The most common toxicities (any grade) were vomiting, diarrhea, anemia, thrombocytopenia, anorexia, fever, and constipation. Among 68 patients, there were 7 treatment‐related serious adverse events. Partial response and stable disease rates were 5.9% and 25% for all subjects and 2% and 30% for the phase 2 patients, respectively. Median progression‐free and overall survival of all patients were 2.0 and 11.7 months and 2 and 7.5 months for the phase 2 patients, respectively. Overall survival of the 31 patients with normal lactate dehydrogenase levels was >22.5 months. Pharmacokinetics of both drugs were similar to previous reports.CONCLUSIONS:Imexon plus dacarbazine was well tolerated. The survival data suggest further evaluation in a randomized phase 2 study. Cancer 2010. © 2010 American Cancer Society.
The role of targeted agents in preoperative chemoradiation for rectal cancer
Authors: Wadlow Raymond C. , Ryan David P. 
Published: April 2010

AbstractIn the United States, randomized trials have established preoperative chemoradiation as the standard of care for patients with locally advanced rectal cancer. Pathologic complete response (pCR) rates occur in 10% to 16% of patients and have been shown to be correlated with both disease‐free and overall survival. Therefore, recent efforts incorporating newer cytotoxic and molecularly targeted agents into chemoradiotherapy regimens have reported the pCR rate to be a surrogate marker of clinical outcomes. Substitution of oral fluoropyrimidines, including capecitabine, for infusional 5‐fluorouracil reportedly generated pCR rates of up to 32% in phase 2 studies, but definitive evaluation awaits results from the National Surgical Adjuvant Breast and Bowel Project (NSABP) R‐04 trial. Similarly, regimens incorporating irinotecan generated pCR rates as high as 38%, but to the authors' knowledge have not been evaluated in randomized trials. In contrast, 2 large randomized trials reported that the addition of weekly oxaliplatin to fluoropyrimidine‐based chemoradiation led to an increase in grade 3/4 toxicity but no difference in pCR rates. Early phase trials evaluating the anti‐epidermal growth factor receptor (EGFR) antibody cetuximab in combination with chemoradiation reported modest pCR rates of 5% to 12%, and efforts have focused on identifying biomarkers of response including EGFR copy number, k‐ras mutational status, and both serum and tumor‐specific expression of EGFR ligands. Finally, incorporation of the anti‐vascular endothelial growth factor antibody bevacizumab into chemoradiation appears to be safe and feasible, with initial studies reporting a beneficial effect on vascular normalization and correlations between circulating biomarkers of angiogenesis and pathologic response. Future efforts should include prospective studies of these agents in biomarker‐defined subpopulations, as well as studies of novel agents that target angiogenesis, tumor‐stromal interaction, and the cell signaling pathways implicated in colorectal cancer. Cancer 2010. © 2010 American Cancer Society.
A tetrachromatic model for colorimetric use in mesopic vision
Authors: Polymeropoulos Grigorios , Bisketzis Nikolaos , Topalis Fragkiskos 
Published: April 2010

AbstractIn this article, a tetrachromatic colorimetric model is proposed. Four monochromatic stimuli are used as primaries instead of three to achieve colorimetric matches in mesopic vision. Tetrachromatic colorimetric matches are assumed in such a way so as to hold in both the photopic and the scotopic levels of adaptation. The fourth primary helps to balance the rod contribution in mesopic vision. The proposed model is based on the experimental observations that (a) trichromatic matches can be achieved in any light level and (b) once a tetrachromatic match is made, it holds at all radiances. The main outcome is that (a) only three channels in human vision system are important for color matching at mesopic and photopic levels and (b) additivity can be preserved at all levels once rod input is taken into account. © 2010 Wiley Periodicals, Inc. Col Res Appl, 2011
Color emotions for multi‐colored images
Authors: Solli Martin , Lenz Reiner 
Published: April 2010

AbstractWe investigate the emotional response to colors in ordinary multicolored images. In psychophysical experiments, using both category scaling and interval scaling, observers are asked to judge images using three emotion factors: activity, weight, and heat. The color emotion metric was originally developed for single colors, and later extended to include pairs of colors. The same metric was recently used in image retrieval. The results show that people in general perceive color emotions for multi‐colored images in similar ways, and that observer judgments correlate with the recently proposed method used in image retrieval. The intended usage is in retrieval systems publicly available on the Internet, where both the user and the viewing environment is unknown, which requires novel ways of conducting the psychophysical experiments. © 2010 Wiley Periodicals, Inc. Col Res Appl, 36, 210–221, 2011;
Goniocolorimetry: From measurement to representation in the CIELAB color space
Authors: Simonot Lionel , Hébert Mathieu , Dupraz Damien 
Published: April 2010

AbstractThe classical definitions of color are well adapted to diffusing objects, whose color is almost independent of the viewing angle, and to very glossy object observed in the specular direction in respect to the light source. For glossy or iridescent objects, the color is difficult to characterize due to its dependence on the viewing direction. In order to cope with such objects and to represent their angle‐dependent colors in a colorimetric space, we adapt the CIELAB space to “goniocolorimetric” measurements. A crucial point when defining this space is the statement of the viewing solid angle. First, we suggest performing a BRDF measurement at high angular resolution in order to characterize the gloss of the specimen. Then, since for the definition of colors the CIE recommends cones of half‐angle of 2° or 10°, we propose to convert the measured BRDF into a reflectance factor defined in respect to these solid angles. This procedure is eased by a planar multispectral image of the BRDF, where solid angles are specified by the pixel size. At last, the reflectance factors are converted into CIELAB coordinates. By using this procedure, the perfect white diffuser but also the perfect mirror can be represented in this colorimetric space. © 2010 Wiley Periodicals, Inc. Col Res Appl, 36, 169–178, 2011;
SmartGridRPC: The new RPC model for high performance Grid computing
Authors: Brady Thomas , Dongarra Jack , Guidolin Michele , Lastovetsky Alexey , Seymour Keith 
Published: April 2010

AbstractThe paper presents the SmartGridRPC model, an extension of the GridRPC model, which aims to achieve higher performance. The traditional GridRPC provides a programming model and API for mapping individual tasks of an application in a distributed Grid environment, which is based on the client‐server model characterized by the star network topology. SmartGridRPC provides a programming model and API for mapping a group of tasks of an application in a distributed Grid environment, which is based on the fully connected network topology. The SmartGridRPC programming model and API and its performance advantages over the GridRPC model are outlined in this paper. In addition, experimental results using a real‐world application are also presented. Copyright © 2010 John Wiley & Sons, Ltd.
Low‐voltage bulk‐driven input stage with improved transconductance
Authors: Raikos George , Vlassis Spyridon 
Published: April 2010

AbstractA low‐voltage input stage constructed from bulk‐driven PMOS transistors is proposed in this paper. It is based on a partial positive feedback and offers significant improvement of both input transconductance and noise performance compared with those achieved by the corresponding already published bulk‐driven structures. The proposed input stage offers also extended input common‐mode range under low supply voltage in relevant to a gate‐driven differential pair. A differential amplifier based on the proposed input stage is also designed, which includes an auxiliary amplifier for the output common‐mode voltage stabilization and a latch‐up protection circuitry. Both input stage and amplifier circuits were implemented with 1 V supply voltage using standard 0.35µm CMOS process, and their performance evaluation gave very promising results. Copyright © 2010 John Wiley & Sons, Ltd.