Best Results (best + result)

Distribution by Scientific Domains
Distribution within Chemistry


Selected Abstracts


Simultaneous Quantification of Heavy Metals Using a Solid State Potentiometric Sensor Array

ELECTROANALYSIS, Issue 8 2009
Jesús Gismera
Abstract A potentiometric sensor array of four nonspecific electrodes with solid-state membranes is developed and tested for simultaneous analysis of copper(II), mercury(II), and silver(I) ions. The cross-sensitivity responses of the sensors for these ions are evaluated. The array potentiometric signals are processed by partial least-squares regression (PLS) and back propagation artificial neural networks (ANN) to determinate analyte concentrations. The ANN configuration is optimized and two different training algorithms of the ANN are also evaluated. Best results are obtained when the potentiometric sensors are activated and the data are processed using ANN and the gradient descent adaptive algorithm. The system is used to quantify these heavy metals in synthetic samples and in dental amalgams with successful results. [source]


CE-MS method development for peptides analysis, especially hepcidin, an iron metabolism marker

ELECTROPHORESIS, Issue 15 2009
Gaëlle B. Martin
Abstract A method for the resolution of a peptides mixture including hepcidin-25, an iron metabolism marker, was developed by CE-ESI-MS. Several strategies were tested to optimize peptide separation, such as the addition of cyclodextrins or organic solvents in the BGE or the use of coated capillaries. Best results in terms of resolution, symmetry and efficiency were obtained with a BGE made of 500,mM ammonium acetate pH 4.5/ACN 70:30,v/v. Using the methodology of experimental design, BGE concentration, sheath liquid composition and MS-coupling parameters were then optimized in order to obtain the best signal intensity for hepcidin. Finally, a 225,mM BGE and a sheath liquid composed of isopropanol/water 80:20,v/v containing 0.5%,v/v formic acid were selected as it constitutes the best compromise for selectivity, peak shape and sensitivity. [source]


Vision enhancement system for detection of oral cavity neoplasia based on autofluorescence

HEAD & NECK: JOURNAL FOR THE SCIENCES & SPECIALTIES OF THE HEAD AND NECK, Issue 3 2004
Ekaterina Svistun MS
Abstract Background. Early detection of squamous cell carcinoma (SCC) in the oral cavity can improve survival. It is often difficult to distinguish neoplastic and benign lesions with standard white light illumination. We evaluated whether a technique that capitalizes on an alternative source of contrast, tissue autofluorescence, improves visual examination. Methods. Autofluorescence of freshly resected oral tissue was observed visually and photographed at specific excitation/emission wavelength combinations optimized for response of the human visual system and tissue fluorescence properties. Perceived tumor margins were indicated for each wavelength combination. Punch biopsies were obtained from several sites from each specimen. Sensitivity and specificity were evaluated by correlating histopathologic diagnosis with visual impression. Results. Best results were achieved with illumination at 400 nm and observation at 530 nm. Here, sensitivity and specificity were 91% and 86% in discrimination of normal tissue from neoplasia. This compares favorably with white light examination, in which sensitivity and specificity were 75% and 43%. Conclusions. Oral cavity autofluorescence can be easily viewed by the human eye in real time. Visual examination of autofluorescence enhances perceived contrast between normal and neoplastic oral mucosa in fresh tissue resections. © 2004 Wiley Periodicals, Inc. Head Neck26: 205,215, 2004 [source]


Enantioselective Copper-Catalysed Allylic Alkylation of Cinnamyl Chlorides by Grignard Reagents using Chiral Phosphine-Phosphite Ligands

ADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 11-12 2010
Wibke Lölsberg
Abstract The copper(I)-catalysed SN2,-type allylic substitution of E -3-aryl-allyl chlorides (cinnamyl chlorides) using Grignard reagents represents a powerful method for the synthesis of compounds carrying a benzylic stereocentre. By screening a small library of modular chiral phosphine-phosphite ligands a new copper(I)-based catalyst system was identified which allows the performance of such reactions with exceptional high degrees of regio- and enantioselectivity. Best results were obtained using TADDOL-derived ligands (3,mol%), copper(I) bromide,dimethyl sulfide (CuBr,SMe2) (2.5,mol%) and methyl tert -butyl ether (MTBE) as a solvent. Various (1-alkyl-allyl)benzene derivatives were prepared with up to 99% ee (GC) in isolated yields of up to 99%. In most cases the product contained less than 3% of the linear regioisomer (except for ortho -substituted substrates). Both electron-rich and electron-deficient cinnamyl chlorides were successfully employed. The absolute configuration of the products was assigned by comparison of experimental and calculated CD spectra. The substrates were prepared from the corresponding alcohols by reaction with thionyl chloride. Initially formed mixtures of regioisomeric allylic chlorides were homogenised by treatment with CuBr,SMe2 (2.5,mol%) in the presence of triphenyl phosphine (PPh3) (3,mol%) in MTBE at low temperature to give the pure linear isomers. In reactions with methylmagnesium bromide (MeMgBr) an ortho -diphenylphosphanyl-arylphosphite ligand with an additional phenyl substituent in ortho, -position at the aryl backbone proved to be superior. In contrast, best results were obtained in the case of higher alkyl Grignard reagents (such as ethyl-, n -butyl-, isopropyl-, and 3-butenylmagnesium bromides) with a related ligand carrying an isopropyl substituent in ortho, -position. The method was tested on a multi-mmol scale and is suited for application in natural product synthesis. [source]


Screening for mental disorders in cancer patients , discriminant validity of HADS and GHQ-12 assessed by standardized clinical interview

INTERNATIONAL JOURNAL OF METHODS IN PSYCHIATRIC RESEARCH, Issue 2 2001
Katrin Reuter
Abstract The detection and classification of comorbid mental disorders has major implications in cancer care. Valid screening instruments for different diagnostic specifications are therefore needed. This study investigated the discriminant validity of the German versions of the Hospital Anxiety and Depression Scale (HADS) and the General Health Questionnaire (GHQ-12). A total of 188 cancer patients participated in the examination, consisting first of the assessment of psychological distress and, second, of the diagnosis of mental disorders according to DSM-IV by clinical standardized interview (CIDI). Discriminant validity of the two instruments regarding the diagnosis of any mental disorder, anxiety, depression and multiple mental disorders was compared using ROC analysis. Overall, the total HADS scale shows a better screening performance than the GHQ-12, especially for the detection of depressive and anxiety disorders. Best results are achieved for depressive disorders with an area under the curve (AUC) of 0.80, a sensitivity of 79% and a specificity of 76% (cut-off point = 17). For the ability of the instruments to detect patients with mental disorders in general, the GHQ-12 (AUC: 0.68) shows a similar overall accuracy to the HADS (AUC: 0.70). The screening performance of both scales for comorbid mental disorders is comparable. The HADS is a valid screening instrument for depressive and anxiety disorders in cancer care. The GHQ-12 can be considered as an alternative to the HADS when diagnostic specifications are less detailed and the goal of screening procedures is to detect patients with single or multiple mental disorders in general. Limitations of conventional screening instruments are given through the differing methodological approaches of screening tests (dimensional approach) and diagnosis according to DSM-IV (categorical approach). Copyright © 2001 Whurr Publishers Ltd. [source]


Micellar Effects in Olefin Hydroformylation Catalysed by Neutral, Calix[4]arene-Diphosphite Rhodium Complexes

ADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 10 2009
Laure Monnereau
Abstract The combination of calixarene-derived surfactants and neutral rhodium complexes containing a hemispherical "1,3-calix-diphosphite" ligand led to efficient catalysts for the hydroformylation of octene and other olefins in water. While the surfactants allowed the formation of micelles that dissolve both the catalyst and the alkene, thereby resulting in high olefin:rhodium ratios, the diphosphite provided a tight envelope about the catalytic centre able to drive the reaction towards the linear aldehydes. Best results in the hydroformylation of 1-octene were obtained when using [tetra(p -sulfonato)]-(tetra- n -butoxy)-calix[4]arene as surfactant. With this additive remarkable linear to branched aldehyde ratios of up to 62 were obtained, the corresponding activities being higher than those observed when operating in an organic solvent [turnover frequencies (TOFs) up to 630 mol(converted 1-octene), mol(Rh),1,h,1]. [source]


A Mild, One-Pot Synthesis of Arylamines via Palladium- Catalyzed Addition of Aryl Aldehydes with Amines and Arylboronic Acids in Water

ADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 5 2009
Ajuan Yu
Abstract A mild, one-pot synthesis of diarylmethylamines via the palladium-catalyzed addition of aryl aldehydes with amines and arylboronic acids is reported. Best results were obtained in neat water with ammonium chloride as additive, affording diarylmethylamine derivatives as the main products. [source]


Iron-Catalyzed Oxidation of Cycloalkanes and Alkylarenes with Hydrogen Peroxide

ADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 5 2005
Chiara Pavan
Abstract An iron-catalyzed process for the oxidation of saturated hydrocarbons (cycloalkanes and alkylarenes) to alcohols and ketones with aqueous H2O2 in acetonitrile at room temperature is reported. Addition of a carboxylic acid increases the selectivity towards the ketone formation. Best results were obtained with ethylbenzene as substrate and acetic acid as additive, affording acetophenone as the main product. [source]


The microencapsulation of terbinafine via in situ polymerization of melamine-formaldehyde and their application to cotton fabric

JOURNAL OF APPLIED POLYMER SCIENCE, Issue 6 2010
Gökhan Erkan
Abstract In this study an antifungal pharmaceutical agent, terbinafine, was microencapsulated by using in situ polymerization. The polymerization was carried out at four mole ratio level and preparations were applied to the 100% cotton fabric. X-ray diffractometry, DSC, FTIR, BET, contact angle measurements, particle size distribution and imaging techniques were performed. Best results were obtained in the case of 8 : 1 mole ratio. Strength of microcapsule applied fabrics to washing and fungus were also determined. After 25 washing cycle, microcapsules were still in the fabric and had antifungal properties against A. niger. Antifungal strength against T. rubrum was observed up to 15 washing cycles. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010 [source]


Glycopeptide dendrimers, Part III,a review: Use of glycopeptide dendrimers in immunotherapy and diagnosis of cancer and viral diseases

JOURNAL OF PEPTIDE SCIENCE, Issue 5 2008
Petr Niederhafner
Abstract Glycopeptide dendrimers containing different types of tumor associated-carbohydrate antigens (TN, TF, sialyl-TN, sialyl-TF, sialyl-Lex, sialyl-Lea etc.) were used in diagnosis and therapy of different sorts of cancer. These dendrimeric structures with incorporated T-cell epitopes and adjuvants can be used as antitumor vaccines. Best results were obtained with multiantigenic vaccines, containing, e.g. five or six different TAAs. The topic of TAAs and their dendrimeric forms at molecular level are reviewed, including structure, syntheses, and biological activities. Use of glycopeptide dendrimers as antiviral vaccines against HIV and influenza is also described. Their syntheses, physico-chemical properties, and biological activities are given with many examples. Copyright © 2008 European Peptide Society and John Wiley & Sons, Ltd. [source]


Cascade Reactions in Polymeric Nanoreactors: Mono (Rh)- and Bimetallic (Rh/Ir) Micellar Catalysis in the Hydroaminomethylation of 1-Octene

MACROMOLECULAR CHEMISTRY AND PHYSICS, Issue 11 2008
Barbara Gall
Abstract The concept of micellar catalysis was transferred to the hydroaminomethylation of 1-octene with N,N -dimethylamine. In the first series of experiments a rhodium(I) complex with amphiphilic triphenylphosphane functionalized poly(2-oxazoline)s as macroligand was applied as catalyst. Results obtained under standard hydroformylation conditions (T,=,100,°C, p,=,50 bar) were not satisfying with regard to activities and selectivities of the hydroaminomethylation reaction. Rising the temperature to 150,°C increased the yield of amine to 22% with a corresponding n/iso selectivity of 7.5 and a TOF number of 461 h,1. Best results were obtained by applying a dual Rh/Ir catalyst within the polymeric micelles leading at lower temperature of 130,°C to an amine yield of 24% with a corresponding n/iso selectivity of 11 and TOF numbers of about 600 h,1. [source]


PVC and LDPE for packing minimally processed garlic

PACKAGING TECHNOLOGY AND SCIENCE, Issue 3 2002
Nilda de Fátima Ferreira Soares
Abstract Minimum processing associated with an adequate packing system has shown good results in preserving a large group of perishable horticultural produce. The present work was done to determine the effect of the number of layered of low-density polyethylene (LDPE) or polyvinyl chloride (PVC) film on the quality of minimally processed packed garlic (Allium sativum), known for its short shelf-life. Polystyrene trays containing 200,g garlic bulbils were wrapped in one to four layers of PVC or one or two layers of LDPE and stored at room temperature. Changes in weight, bulbil colouration, in-package gas composition and apparent quality were monitored for 14 days. Best results were obtained by wrapping the packages in four layers of PVC film, with insignificant weight loss (5%), changes in colour tone and saturation, and the in-pack atmosphere (O2,=,0.01% and CO2,=,13.5%) inhibited fungal growth, extending shelf-life to 13 days at 25,±,2°C. On the other hand, the high in-package moisture in LDPE wrapping favoured fungal growth, rapidly depreciating bulbil quality. The shelf-life of minimally processed garlic can be increased by maintaining an adequate in-pack atmosphere, which can be achieved by using four layers of PVC or a another film of similar permeability. Copyright © 2002 John Wiley & Sons, Ltd. [source]


Influence of supported vanadium catalyst on ethylene polymerization reactions

POLYMER INTERNATIONAL, Issue 2 2008
Sutapa Ghosh
Abstract BACKGROUND: In the research area of homogeneous Ziegler,Natta olefin polymerization, classic vanadium catalyst systems have shown a number of favourable performances. These catalysts are useful for (i) the preparation of high molecular weight polymers with narrow molecular weight distributions, (ii) the preparation of ethylene/R -olefin copolymers with high R -olefin incorporation and (iii) the preparation of syndiotactic polypropylenes. In view of the above merits of vanadium-based catalysts for polymerization reactions, the development of well-defined single-site vanadium catalysts for polymerization reactions is presently an extremely important industrial goal. The main aim of this work was the synthesis and characterization of a heterogeneous low-coordinate non-metallocene (phenyl)imido vanadium catalyst, V(NAr)Cl3, and its utility for ethylene polymerization. RESULTS: Imido vanadium complex V(NAr)Cl3 was synthesized and immobilized onto a series of inorganic supports: SiO2, methylaluminoxane (MAO)-modified SiO2 (4.5 and 23 wt% Al/SiO2), SiO2 Al2O3, MgCl2, MCM-41 and MgO. Metal contents on the supported catalysts determined by X-ray fluorescence spectroscopy remained between 0.050 and 0.100 mmol V g,1 support. Thermal stability of the catalysts was determined by differential scanning calorimetry (DSC). Characterization of polyethylene was done by gel permeation chromatography and DSC. All catalyst systems were found to be active in ethylene polymerization in the presence of MAO or triisobutylaluminium/MAO mixture (Al/V = 1000). Catalyst activity was found to depend on the support nature, being between 7.5 and 80.0 kg PE (mol V),1 h,1. Finally, all catalyst systems were found to be reusable for up to three cycles. CONCLUSION: Best results were observed in the case of silica as support. Acid or basic supports afforded less active systems. In situ immobilization led to higher catalyst activity. The resulting polyethylenes in all experiments had ultrahigh molecular weight. Finally, this work explains the synthesis and characterization of reusable supported novel vanadium catalysts, which are useful in the synthesis of very high molecular weight ethylene polymers. Copyright © 2007 Society of Chemical Industry [source]


Design of new poly(ethylene) based materials by coordination (co)polymerization of macromonomers with ethylene,

POLYMERS FOR ADVANCED TECHNOLOGIES, Issue 9-10 2006
J.-F. Lahitte
Abstract The present work discusses first the homopolymerization of , -allyl, , -undecenyl or , -vinylbenzyl polystyrene (PS) macromonomers in the presence of selected early or late transition metal catalysts. Homopolymerization degrees were found to depend on the type of catalyst, the terminal double bond, the polymerization temperature and the concentration of the various species. Higher molar masses were reached at low temperatures and low catalyst and cocatalyst concentrations. Best results were obtained with the constrained geometry catalyst (CGC)-Ti. The same PS macromonomers were copolymerized with ethylene in the presence of the VERSIPOLTM catalyst to design a new type of poly(ethylene) based graft copolymer. The macromonomer weight percent content decreases with increasing ethylene pressure whereas the molar mass of the copolymer increases with ethylene pressure. The PS macromonomer content as well as the molar mass of the copolymer can be still increased by using ,,, -difunctional PS macromonomers. The dilute solution and solid-state behavior of these copolymers were examined and compared to those of poly(ethylenes) prepared under the same conditions. Copyright © 2006 John Wiley & Sons, Ltd. [source]


Sleep Disordered Breathing: Surgical Outcomes in Prepubertal Children

THE LARYNGOSCOPE, Issue 1 2004
BiolD, Christian Guilleminault MD
Abstract Objective To evaluate the treatment outcomes of sleep disordered breathing (SDB) in prepubertal children 3 months following surgical intervention. Study Design Retrospective investigation of 400 consecutively seen children with SDB who were referred to otolaryngologists for treatment. Method After masking the identities and conditions of the children, the following were tabulated: clinical symptoms, results of clinical evaluation and polysomnography at entry, the treatment chosen by the otolaryngologists, and clinical and polysomnographic results 3 months after surgery. Results Treatment ranged from nasal steroids to various surgical procedures. Adenotonsillectomy was performed in only 251 of 400 cases (68%). Four cases included adenotonsillectomy in conjunction with pharyngoplasty (closure of the tonsillar wound by suturing the anterior and posterior pillar to tighten the airway). Persistent SDB was seen in 58 of 400 children (14.5%), and an additional 8 had persistent snoring. Best results were with adenotonsillectomy. Conclusion SDB involves obstruction of the upper airway, which may be partially due to craniofacial structure involvement. The goal of surgical treatment should be aimed at enlarging the airway, and not be solely focused on treating inflammation or infection of the lymphoid tissues. This goal may not be met in some patients, thus potentially contributing to residual problems seen after surgery. The possibility of further treatment, including collaboration with orthodontists to improve the craniofacial risk factors, should be considered in children with residual problems. [source]


Influence of different magnetites on properties of magnetic Pseudomonas aeruginosa immobilizates used for biosurfactant production

BIOTECHNOLOGY PROGRESS, Issue 6 2009
M. Heyd
Abstract During the last decades, whole-cell immobilization has been used successfully in many bioprocesses. In particular, it is aimed at implementing continuous production processes, reaching higher production rates, and reusing the biocatalyst. In some cases, effective retention of immobilizates in the bioprocess is not feasible by membranes or sieves due to pore plugging or undesired losses of immobilizates. In the present publication, it is reported about the investigation of magnetic immobilizates of Pseudomonas aeruginosa for application in continuous biosurfactant production of rhamnolipids by foam fractionation and retention of entrained immobilizates by high-gradient magnetic separation from foam. Different materials and methods were tested with respect to important parameters, such as stability, diffusion properties or magnetic separation. Good magnetic separation of immobilizates was achieved at 5% (w/w) magnetite loading. Best results in terms of homogeneous embedding, good diffusion properties, and stability enhancement vis-à-vis pure alginate beads was achieved with alginate beads with embedded Bayoxide® magnetite or MagPrep® silica particles. Although polyurethane immobilizates showed higher stabilities compared with alginate beads, rhamnolipid diffusion in immobilizates was superior in magnetic alginate beads. Regarding bead production, smaller immobilizates were achieved with suspension polymerization compared to droplet extrusion by the JetCutting® technology. In total, magnetic immobilizates are a promising tool for an easier handling of biocatalysts in a continuous biological production process, but they have to be adapted to the current production task.© 2009 American Institute of Chemical Engineers Biotechnol. Prog., 2009 [source]


Synthesis of peptide sequences related to thrombospondin: factors affecting aspartimide by-product formation

CHEMICAL BIOLOGY & DRUG DESIGN, Issue 6 2003
J. Cebrián
Abstract:, Aspartimide formation is one of the most common secondary reactions on solid phase peptide synthesis. In the present work, we describe the optimization of the synthesis of two thrombospondin fragments containing an Asp-Gly sequence that show a strong tendency to form cyclic aspartimide derivatives in an unusual high percentage. Several different strategies were applied changing type of resin, Fmoc-deprotection reagents, coupling additives, resin cleavage cocktails and the use of Hmb-Gly derivative to minimize the extension of this byproduct. Best results were obtained with cross-linked ethoxylate acrylate (CLEAR® -cross-linked ethoxylate Acrylate Resin)-type resin and pip/dimethylformamide deprotection. Besides, as in biological assays the aspartimide containing sequence resulted to be more active than the linear one, the optimization of its synthesis was also carried out. [source]


Position-Invariant Neural Network for Digital Pavement Crack Analysis

COMPUTER-AIDED CIVIL AND INFRASTRUCTURE ENGINEERING, Issue 2 2004
Byoung Jik Lee
This system includes three neural networks: (1) image-based neural network, (2) histogram-based neural network, and (3) proximity-based neural network. These three neural networks were developed to classify various crack types based on the subimages (crack tiles) rather than crack pixels in digital pavement images. These spatial neural networks were trained using artificially generated data following the Federal Highway Administration (FHWA) guidelines. The optimal architecture of each neural network was determined based on the testing results from different sets of the number of hidden units, learning coefficients, and the number of training epochs. To validate the system, actual pavement pictures taken from pavements as well as the computer-generated data were used. The proximity value is determined by computing relative distribution of crack tiles within the image. The proximity-based neural network effectively searches the patterns of various crack types in both horizontal and vertical directions while maintaining its position invariance. The final result indicates that the proximity-based neural network produced the best result with the accuracy of 95.2% despite its simplest neural network structure with the least computing requirement. [source]


Finite element study of the energy dissipation and residual stresses in the closed elastic deformation path

INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN ENGINEERING, Issue 10 2006
B. Abbasi
Abstract In this paper, energy dissipation and residual stress developments are numerically studied in three-dimensional closed deformation paths. Different objective stress rates coded in a finite element program are compared. In order to update the stresses, implicit integration algorithm based on mid-point rule for corotational and non-corotational objective rates is used. Several corotational objective rates such as Jaumann, Green,Naghdi, Eulerian and Lagrangian triad-based rates and non-corotational rates such as Truesdell and Cotter,Rivlin rates are considered. It is shown in this work that in some cases also a non-integrable model may exhibit no dissipation energy at the end of a closed deformation path. This study underlines some results previously obtained by other researchers, i.e. among all considered stress rates the logarithmic rate manifests the best result in respect of elasticity requirements. Copyright © 2006 John Wiley & Sons, Ltd. [source]


Efficacy of 10% silver nitrate solution in the treatment of common warts: a placebo-controlled, randomized, clinical trial

INTERNATIONAL JOURNAL OF DERMATOLOGY, Issue 2 2007
Sedigheh Ebrahimi MD
Background, Warts are a common skin lesion, especially in children and young adults, caused by human papillomaviruses. So far, there is no definitive therapy for warts and the treatment is modified regularly to obtain the best result with the least discomfort to the patient. The aim of this placebo-controlled clinical trial was to evaluate the clinical efficacy, tolerability, and safety of 10% silver nitrate solution for the treatment of common warts. Methods, Sixty individuals attending pediatrics and dermatology clinics and health centers in Yasuj, south-west of Iran, were recruited. The patients were divided into two groups: 30 patients received 10% silver nitrate solution (case group) and 30 control patients received black ink (placebo group). Silver nitrate solution was used every other day for 3 weeks. After 3 weeks, the patients were evaluated for healing, and treatment was continued for another 3 weeks if the lesions were still present. Results, Complete regression of lesions was achieved in 19 of the 30 (63.33%) case patients. No significant side-effect was noted in the treated patients apart from temporary brownish discoloration of the skin which resolved 1 week after treatment. Conclusion, This study demonstrated that 10% silver nitrate solution can be used effectively for the treatment of warts with no serious complications. [source]


Structure of the quaternary alloy Zn0.6Mn0.4In2S4 from synchrotron powder diffraction and electron transmission microscopy

JOURNAL OF APPLIED CRYSTALLOGRAPHY, Issue 1 2006
Asiloé J. Mora
The aim of the present work was to determine the structure of the quaternary alloy Zn0.6Mn0.4In2S4 and to locate the Mn2+. This was accomplished by means of powder synchrotron X-ray diffraction, high-resolution microscopy and convergent-beam electron diffraction (CBED). The powder X-ray diffraction pattern was indexed in a rhombohedral cell, with cell constants a = 3.875,(2), c = 37.208,(4),Å, and possible space groups Rm or R3m. Rietveld refinements using different cationic arrangements in these space groups were performed. A model in space group R3m, in which the tetrahedral and octahedral sites were occupied by different proportions of Zn, Mn and In atoms, gave the best result. The Rietveld refinement of this model led to figures of merit Rwp = 9.8%, Rp = 9.1% and ,2 = 11.1. Selected-area electron diffraction patterns and high-resolution transmission electron micrographs along [001] reveal the rhombohedral configuration. CBED patterns perpendicular to [001], showing the distinctive 3m symmetry, confirmed space group R3m and the breaking of the centrosymmetry of the parent compound, ZnIn2S4. [source]


More effective induction of spawning with long-acting GnRH agonist in the shi drum, Umbrina cirrosa L. (Sciaenidae, Teleostei), a valuable candidate for Mediterranean mariculture

JOURNAL OF APPLIED ICHTHYOLOGY, Issue 3 2002
A. Barbaro
Three experiments of spawning induction in shi drum, Umbrina cirrosa L., were performed in six different commercial Italian hatcheries from May to August (water temperatures: 19,29 °C; salinity: 21,37 p.p.t.). In the first experiment, 119 females (1,4.7 kg), subdivided into 29 lots, were injected with a single dose (2, 5, 8, 10, 15 and 20 ,g kg,1 body weight) of short-acting gonadotropin- releasing hormone agonist (GnRHa-S), des-Gly10,[D-Ala6]-LH-RH ethylamide. In the other two experiments, 85 females (0.7,5.8 kg), subdivided into 22 and four lots, were treated with one (40 or 80 ,g kg,1) or three doses (40 ,g kg,1) of long-acting GnRHa (GnRHa-L), respectively. GnRHa-S stimulated spawning in 69% of the 29 treated lots; the number of eggs laid reached a maximum of 130 000 and a weighted mean of 29 200 total eggs kg,1. GnRHa-L elicited a spawning response in 95% of the 22 one-dose treated lots; the number of laid eggs was higher than with GnRHa-S, reaching a maximum of 213 100 and a weighted mean of 59 400 total eggs kg,1. The yield of developing embryos in 67% of the single GnRHa-L treatments was higher (sometimes up to three times) than with GnRHa-S. Triple treatments of the four lots of females with GnRHa-L always resulted in spawning responses; the best result corresponded to a number of total laid eggs of 358 900 eggs kg,1 with a yield of 177 300 developing embryos. [source]


Synthesis and evaluation of 2-, 4-, 5-substituted nitroimidazole-iminodiacetic acid- 99mTc(CO)3 complexes to target hypoxic tumors

JOURNAL OF LABELLED COMPOUNDS AND RADIOPHARMACEUTICALS, Issue 8 2010
Madhava B. Mallia
Abstract Determination of hypoxia in tumor is an important problem in the clinical management of cancer. Towards this, a series of differently substituted nitroimidazoles, viz. 2-nitro, 4-nitro and 5-nitroimidazole iminodiacetic acid (IDA) derivatives were synthesized and radio-labeled with a [99mTc(CO)3(H2O)3]+ core. The corresponding 185/187Re(CO)3 analogue of 2-nitroimidazole-IDA- 99mTc(CO)3 complex was also prepared and characterized to elucidate the mode of bonding between the ligand and the M(CO)3 core (M=99mTc, 185/187Re). All the three nitroimidazole-IDA- 99mTc(CO)3 complexes could be prepared in over 95% yield determined by HPLC. The three complexes were then evaluated in a suitable animal model bearing tumor. Though the in vivo accumulation of complexes in hypoxic tissue is governed by factors such as lipophilicity, charge, etc., the variation in accumulation in hypoxic tissue, in the present case, could be explained by considering the reported values of single electron reduction potential of the respective nitroimidazoles. Among the three derivatives studied, the 2-nitroimidazole-IDA- 99mTc(CO)3 complex produced the best result followed by the 5-nitroimidazole complex. Copyright © 2010 John Wiley & Sons, Ltd. [source]


Multivariable real-time optimal control of a cooling and antisolvent semibatch crystallization process

AICHE JOURNAL, Issue 10 2009
Milana Trifkovic
Abstract This article presents an experimental study of simultaneous optimization with respect to two variables (cooling rate and flow-rate of antisolvent) in an offline and online (real-time) manner on a semibatch crystallizer. The nucleation and growth kinetic parameters of paracetamol in an isopropanol-water cooling, antisolvent batch crystallizer were estimated by nonlinear regression in terms of the moments of the crystal population density. Moments of crystal population were estimated from the measured chord length distribution, generated by the FBRM®, and the supersaturation was calculated from the measured concentration by attenuated total reflectance-fourier transform infrared spectroscopy. The results of real-time optimization showed a substantial improvement of the end of batch properties (the volume-weighted mean size and yield). For the same objective function, the real-time optimization method resulted in an increase in the volume-weighted mean size by ,100 ,m and 15% of theoretical yield compared with the best result obtained in an offline optimization manner. © 2009 American Institute of Chemical Engineers AIChE J, 2009 [source]


Effects of feeding and induction strategy on the production of BmR1 antigen in recombinant E. coli

LETTERS IN APPLIED MICROBIOLOGY, Issue 5 2009
A. Norsyahida
Abstract Aim:, To investigate the effects of feeding and induction strategies on the production of BmR1 recombinant antigen. Methods and Results:, Fed-batch fermentation was studied with respect to the specific growth rate and mode of induction to assess the growth potential of the bacteria in a bioreactor and to produce high yield of BmR1 recombinant antigen. Cells were grown at a controlled specific growth rate (,set) during pre-induction, followed by constant feeding postinduction. The highest biomass (24·3 g l,1) was obtained during fed-batch process operated at ,set of 0·15 h,1, whereby lower ,set (0·075 h,1) gave the highest protein production (9·82 mg l,1). The yield of BmR1 was increased by 1·2-fold upon induction with 1 mmol l,1 IPTG (isopropyl-,- d -thiogalactoside) compared to using 5 mmol l,1 and showed a further 3·5-fold increase when the culture was induced twice at the late log phase. Conclusions:, Combination of feeding at a lower ,set and twice induction with 1 mmol l,1 IPTG yielded the best result of all variables tested, promising an improved method for BmR1 production. Significance and Impact of the Study:, This method can be used to increase the production scale of the BmR1 recombinant antigen to meet the increasing demand for Brugia RapidÔ, a commercial diagnostic test for detection of brugian filariasis. [source]


BqR-Tree: A Data Structure for Flights and Walkthroughs in Urban Scenes with Mobile Elements

COMPUTER GRAPHICS FORUM, Issue 6 2010
J.L. Pina
I.3.6 [Computer Graphics]: Graphics data structures and data types Abstract BqR-Tree, the data structure presented in this paper is an improved R-Tree data structure based on a quadtree spatial partitioning which improves the rendering speed of the usual R-trees when view-culling is implemented, especially in urban scenes. The city is split by means of a spatial quadtree partition and the block is adopted as the basic urban unit. One advantage of blocks is that they can be easily identified in any urban environment, regardless of the origins and structure of the input data. The aim of the structure is to accelerate the visualization of complex scenes containing not only static but dynamic elements. The usefulness of the structure has been tested with low structured data, which makes its application appropriate to almost all city data. The results of the tests show that when using the BqR-Tree structure to perform walkthroughs and flights, rendering times vastly improve in comparison to the data structures which have yielded best results to date, with average improvements of around 30%. [source]


Reconstructing head models from photographs for individualized 3D-audio processing

COMPUTER GRAPHICS FORUM, Issue 7 2008
M. Dellepiane
Abstract Visual fidelity and interactivity are the main goals in Computer Graphics research, but recently also audio is assuming an important role. Binaural rendering can provide extremely pleasing and realistic three-dimensional sound, but to achieve best results it's necessary either to measure or to estimate individual Head Related Transfer Function (HRTF). This function is strictly related to the peculiar features of ears and face of the listener. Recent sound scattering simulation techniques can calculate HRTF starting from an accurate 3D model of a human head. Hence, the use of binaural rendering on large scale (i.e. video games, entertainment) could depend on the possibility to produce a sufficiently accurate 3D model of a human head, starting from the smallest possible input. In this paper we present a completely automatic system, which produces a 3D model of a head starting from simple input data (five photos and some key-points indicated by user). The geometry is generated by extracting information from images and accordingly deforming a 3D dummy to reproduce user head features. The system proves to be fast, automatic, robust and reliable: geometric validation and preliminary assessments show that it can be accurate enough for HRTF calculation. [source]


Rapid and easy semi-quantitative evaluation method for diacylglycerol and inositol-1,4,5-trisphosphate generation in orexin receptor signalling

ACTA PHYSIOLOGICA, Issue 3 2010
M. E. Ekholm
Abstract Aim:, Fluorescent protein-based indicators have enabled measurement of intracellular signals previously nearly inaccessible for studies. However, indicators showing intracellular translocation upon response suffer from serious limitations, especially the very time-consuming data collection. We therefore set out in this study to evaluate whether fixing and counting cells showing translocation could mend this issue. Methods:, Altogether three different genetically encoded indicators for diacylglycerol and inositol-1,4,5-trisphosphate were transiently expressed in Chinese hamster ovary cells stably expressing human OX1 orexin receptors. Upon stimulation with orexin-A, the cells were fixed with six different protocols. Results:, Different protocols showed clear differences in their ability to preserve the indicator's localization (i.e. translocation after stimulus) and its fluorescence, and the best results for each indicator were obtained with a different protocol. The concentration,response data obtained with cell counting are mostly comparable to the real-time translocation and biochemical data. Conclusion:, The counting method, as used here, works at single time point and looses the single-cell-quantitative aspect. However, it also has some useful properties. First, it easily allows processing of a 100- to 1000-fold higher cell numbers than real-time imaging producing statistically consistent population-quantitative data much faster. Secondly, it does not require expensive real-time imaging equipment. Fluorescence in fixed cells can also be quantitated, though this analysis would be more time-consuming than cell counting. Thirdly, in addition to the quantitative data collection, the method could be applied for identifying responsive cells. This might be very useful in identification of e.g. orexin-responding neurones in a large population of non-responsive cells in primary cultures. [source]


Colposcopy carried out by experts in multidisciplinary teams provides the best results

CYTOPATHOLOGY, Issue 6 2008
Santiago Dexeus
No abstract is available for this article. [source]


Clinical Trial of Dual Treatment with an Ablative Fractional Laser and a Nonablative Laser for the Treatment of Acne Scars in Asian Patients

DERMATOLOGIC SURGERY, Issue 7 2009
SANGEUN KIM MD
BACKGROUND Many methods have been proposed for the treatment of acne scars, with variable cosmetic results. Nonablative skin resurfacing is one method that has been proposed. Because of a need for more noticeable clinical improvements, the ablative fractional laser was recently introduced. OBJECTIVE To reduce complications and improve the results of ablative fractional laser resurfacing by combining this treatment of acne scars with nonablative lasers. METHODS A series of 20 patients (skin phototypes IV,V) with atrophic facial acne scars were randomly divided into two groups that received three successive monthly treatments with an ablative fractional laser using high (group A) and low (group B) energy on one facial half and an ablative fractional laser with low energy plus a nonablative resurfacing laser on the other facial half. Patients were evaluated using digital photography at each treatment visit and at 3 months postoperatively. Clinical assessment scores were determined at each treatment session and follow-up visit. RESULTS Although the use of the ablative fractional laser with high energy resulted in an improvement in patients' acne scars, the combination of ablative fractional laser resurfacing and nonablative laser resurfacing yielded the best results, as assessed in photographs as well as by the overall appearance of the acne scars. With the combination method, fewer complications were observed. [source]