bluuebunny/crossref_metadata_2025_split huggingface dataset:
Optimization of a multiphase sensor for detection of phosphonates in air
Authors: Monty Chelsea N. , Oh Ilwhan , Masel Richard I. 
Published: October 2009

AbstractThe objective of this article is to report the modeling and optimization of a new MEMS‐based phosphonate sensor that utilizes a porous membrane between a gas and a liquid stream to allow operation at low‐liquid and high‐gas flow rates. Previous work from our laboratory demonstrated that phosphonate molecules can be detected with such a device, but the sensitivity was insufficient for certain applications (e.g., detection of pesticides in foodstuffs). In this article, COMSOL simulations and design of experiments were used to optimize the device. We find that both the simulation and the experiment show that (i) the size of the pores in the membranes and (ii) the liquid channel height make the most difference to the sensor response. Also, by optimizing the geometry, the sensitivity of the device could be enhanced. The optimized device can detect 109 molecules with good signal to noise. © 2009 American Institute of Chemical Engineers AIChE J, 2010
Improved extraction of vanadium from a Chinese vanadium‐bearing stone coal using a modified roast‐leach process
Authors: Chen Tiejun , Zhang Yimin , Song Shaoxian 
Published: October 2009

AbstractVanadium is a rare metal mainly used in the steel industry. Vanadium‐bearing stone coal is an important source of vanadium in China. The common process used to extract vanadium from the stone coals is roast‐leach, which has the disadvantages of low vanadium recovery and significant pollution. This work presents a modified roast‐leach process in order to improve the efficiency of the extraction. The modifications include a two‐step leaching process: first water leach, followed by an acid leach of the water‐leaching residue in a dilute HCl solution. In addition, the precipitate was recycled from the acid‐leaching solution to the oxidation roast for use as a roasting agent, and low dosages of sodium salts (Na2CO3 and Na2SO4) were included in the oxidation roast to reduce the volume of HCl and Cl2 exhaust gases and environmental pollution. The study was performed on a typical vanadium‐bearing stone coal from the Xiushui mine in Jiangxi province, China. The results show that the modified process achieved a vanadium recovery of 85% from the stone coal, much higher than that from a one‐step leach process (water leach or acid leach alone). Also, it has been found that optimum values of the roast temperature and time in the preroast (750 °C and 30 min) and oxidation roast (780 °C and 90 min) were required in order to obtain the maximum vanadium recovery from stone coal. It is shown that the modified roast‐leach process is an economic and effective process for the recovery of vanadium from stone coals. Copyright © 2009 Curtin University of Technology and John Wiley & Sons, Ltd.
A validated model of GAG deposition, cell distribution, and growth of tissue engineered cartilage cultured in a rotating bioreactor
Authors: Nikolaev N.I. , Obradovic B. , Versteeg H.K. , Lemon G. , Williams D.J. 
Published: October 2009

AbstractIn this work a new phenomenological model of growth of cartilage tissue cultured in a rotating bioreactor is developed. It represents an advancement of a previously derived model of deposition of glycosaminoglycan (GAG) in engineered cartilage by (i) introduction of physiological mechanisms of proteoglycan accumulation in the extracellular matrix (ECM) as well as by correlating (ii) local cell densities and (iii) tissue growth to the ECM composition. In particular, previously established predictions and correlations of local oxygen concentrations and GAG synthesis rates are extended to distinguish cell secreted proteoglycan monomers free to diffuse in cell surroundings and outside from the engineered construct, from large aggrecan molecules, which are constrained within the ECM and practically immovable. The model includes kinetics of aggregation, that is, transformation of mobile GAG species into immobile aggregates as well as maintenance of the normal ECM composition after the physiological GAG concentration is reached by incorporation of a product inhibition term. The model also includes mechanisms of the temporal evolution of cell density distributions and tissue growth under in vitro conditions. After a short initial proliferation phase the total cell number in the construct remains constant, but the local cell distribution is leveled out by GAG accumulation and repulsion due to negative molecular charges. Furthermore, strong repulsive forces result in expansion of the local tissue elements observed macroscopically as tissue growth (i.e., construct enlargement). The model is validated by comparison with experimental data of (i) GAG distribution and leakage, (ii) spatial‐temporal distributions of cells, and (iii) tissue growth reported in previous works. Validation of the model predictive capability—against a selection of measured data that were not used to construct the model—suggests that the model successfully describes the interplay of several simultaneous processes carried out during in vitro cartilage tissue regeneration and indicates that this approach could also be attractive for application in other tissue engineering systems. Biotechnol. Bioeng. 2010. 105: 842–853. © 2009 Wiley Periodicals, Inc.
Systematic engineering of phytochelatin synthesis and arsenic transport for enhanced arsenic accumulation in E. coli
Authors: Singh Shailendra , Kang Seung Hyun , Lee Wonkyu , Mulchandani Ashok , Chen Wilfred 
Published: October 2009

AbstractPhytochelatin (PC) is a naturally occurring peptide with high affinity towards arsenic (As). In this article, we demonstrated the systematic engineering of PC‐producing E. coli for As accumulation by addressing different bottlenecks in PC synthesis as well as As transport. Phytochelatin synthase from Schizosaccharomyces pombe (SpPCS) was expressed in E. coli resulting in 18 times higher As accumulation. PC production was further increased by co‐expressing a feedback desensitized γ‐glutamylcysteine synthetase (GshI*), resulting in 30‐fold higher PC levels and additional 2‐fold higher As accumulation. The significantly increased PC levels were exploited further by co‐expressing an arsenic transporter GlpF, leading to an additional 1.5‐fold higher As accumulation. These engineering steps were finally combined in an arsenic efflux deletion E. coli strain to achieve an arsenic accumulation level of 16.8 µmol/g DCW, a 80‐fold improvement when compared to a control strain not producing phytochelatins. Biotechnol. Bioeng. 2010. 105: 780–785. © 2009 Wiley Periodicals, Inc.
Sentinel lymph node biopsy in breast cancer guided by indocyanine green fluorescence
Authors: Murawa D , Hirche C , Dresel S , Hünerbein M 
Published: October 2009

AbstractBackgroundSentinel lymph node (SLN) biopsy with radioisotope and blue dye has been used successfully for axillary staging in breast cancer. This study evaluated the feasibility of fluorescence detection of SLNs with indocyanine green (ICG) for lymphatic mapping and SLN biopsy.MethodsThirty women with breast cancer had a periareolar injection of ICG for fluorescence detection of SLN using a near-infrared camera. Twenty also received 99mTc-labelled sulphur radiocolloid for SLN scintigraphy. All patients underwent axillary lymph node dissection. Detection rate and sensitivity of both methods were the study endpoints.ResultsVisualization of lymphatic vessels by fluorescence detection depended on the dose of ICG. ICG imaging identified SLNs in 29 of 30 women (detection rate 97 per cent). Nineteen of 21 patients had metastatic SLN involvement (sensitivity 90 per cent) with false-negative results in two. Among the 20 patients who had both methods, ICG fluorescence and radiocolloid identified SLNs in 20 and 17 patients respectively. Metastatic lymph nodes were diagnosed in 12 and ten of 13 patients (sensitivity 92 and 77 per cent). False-negative rates were 8 and 23 per cent respectively.ConclusionICG fluorescence allowed transcutaneous imaging of lymphatic vessels and SLN detection, thus combining the advantages of radioisotope and blue dye methods.
Vector fragmentation: Characterizing vector integrity in transfected clones by Southern blotting
Authors: Ng Say Kong , Lin Wenyu , Sachdeva Rohit , Wang Daniel I.C. , Yap Miranda G.S. 
Published: October 2009

AbstractThe Chinese Hamster Ovary production cell line development process using methotrexate (MTX) amplification is well studied and commonly used for biopharmaceutical processes. However, successful MTX amplification varies from clone to clone and suggested reasons include vector fragmentation during the transfection process and genomic rearrangement of the Chinese Hamster Ovary chromosomes. Here, we elucidated the vector integration patterns of 40 transfected single‐cell clones by Southern blotting and showed that vector fragmentation occurs at a significant level in our experiment. This concurs with MTX amplification studies implying that single‐cell cloning is necessary to ensure a successful amplification process. Truncations at the ends of the integrated vectors were also observed, whereas gross DNA insertions were not detected in our data. This suggests that end deletions are common, whereas insertion events are rare in animal cells. © 2009 American Institute of Chemical Engineers Biotechnol. Prog., 2010
Growth inhibition of dinoflagellate algae in shake flasks: Not due to shear this time!
Authors: Hu Weiwei , Gladue Ray , Hansen Jon , Wojnar Crystal , Chalmers Jeffrey J. 
Published: October 2009

AbstractLarge scale algae cultures present interesting challenges in that they exhibit characteristics of typical bacterial and animal cell cultures. One current commercial food additive, docosahexaenoic acid (DHA), is produced using the dinoflagellate algae, Crypthecodinium cohnii. Like animal cell culture, the perceived sensitivity of algae culture to hydrodynamic forces has potentially limited the agitation and aeration applied to these systems. However, the high density cultivation of C. cohnii required for an economically feasible process inevitably results in high oxygen demand. In this study, we demonstrated what first appeared to be a problem with shear sensitivity in shake flasks is most probably a mass transfer limitation. We subsequently demonstrated the limit of chronic and rapid energy dissipation rate, EDR, that C. cohnii cells can experience. This limit was determined using a microfluidic device connected in a recirculation loop to a stirred tank bioreactor, which has been previously used to repeatedly expose animal cells to high levels of EDR. Inhibition of cell growth was observed when C. cohnii cells were subjected to an EDR of 5.9 × 106 W/m3 with an average frequency of 0.2/min or more. This level of EDR is sufficiently high that C. cohnii can withstand typically encountered hydrodynamic forces in bioprocesses. This result suggests that at least one dinoflagellate algae, C. cohnii, is quite robust with respect to hydrodynamic forces and the scale‐up of process using this type of algae should be more concerned with providing sufficient gas transfer given the relatively high oxygen demand. © 2009 American Institute of Chemical Engineers Biotechnol. Prog., 2010
Synthesis, Inhibition Potency, Binding Mode, and Antiprotozoal Activities of Fluorescent Inhibitors of Trypanothione Reductase Based on Mepacrine‐Conjugated Diaryl Sulfide Scaffolds
Authors: Eberle Christian , Burkhard Johannes A. , Stump Bernhard , Kaiser Marcel , Brun Reto , Krauth‐Siegel R. Luise , Diederich François 
Published: October 2009

AbstractTrypanothione reductase (TR) is a flavoenzyme unique to trypanosomatid parasites and a target for lead discovery programs. Various inhibitor scaffolds have emerged in the past, exhibiting moderate affinity for the parasite enzyme. Herein we show that the combination of two structural motifs of known TR inhibitors — diaryl sulfides and mepacrine — enables the simultaneous addressing of two hydrophobic patches in the active site. The binding efficacy of these conjugates is enhanced over that of the respective parent inhibitors. They show Kic values for the parasite enzyme down to 0.9±0.1 μm and exhibit high selectivity for TR over human glutathione reductase (GR). Despite their considerable molecular mass and in some cases permanent positive charges, in vitro studies revealed IC50 values in the low micromolar to sub‐micromolar range against Trypanosoma brucei rhodesiense and Trypanosoma cruzi, as well as the malaria parasite Plasmodium falciparum, which lack trypanothione metabolism. The inhibitors exhibit strong fluorescence due to their aminoacridine moiety. This feature allows visualization of the drugs in the parasite where high accumulation was observed by fluorescence microscopy even after short exposure times.
Evaluation of a dry format reagent alternative for CD4 T‐cell enumeration for the FACSCount system: A report on a Moroccan–Canadian study
Authors: Bergeron Michèle , Ding Tao , Elharti Elmir , Oumzil Hicham , Soucy Nadia , Harmouche Hicham , Chaouch Saad , Aouad Rajae EL , Chabot Christian , Mandy Francis 
Published: October 2009

AbstractBackground:Efforts to improve alternative CD4 T‐cell counting methods are critical to accelerate the implementation of HIV antiretroviral therapy in resources limited regions. Substituting liquid format reagents to eliminate cold‐chain transportation and refrigerated storage with dry format reagents contributes to higher efficiency supply management solution especially for laboratories at remote locations. ReaMetrix has developed dry format reagent kits compatible with the FACSCount system, a dedicated flow cytometer for T‐cell subset enumeration widely used in resource limited settings. A dual site collaborative study was designed to compare T‐cell subsets using both the new dry format ReaMetrix reagent and the original BD Biosciences liquid reagents.Method:A total of 167 HIV positive samples prepared with Rea T Count (ReaMetrix) and FACSCount (BD Biosciences) reagents were analyzed using FACSCount Systems. To compare both methods, Bland‐Altman, Pollock, Scott % similarity and correlation coefficient statistical analysis was applied. Immuno‐Trol served as an assay processing control and quality indicator of interlaboratory and intralaboratory variation.Results:The mean bias and limits of agreement for CD4 T‐cell measurements between Rea T Count and FACSCount reagents were −16 cells/μl (−4.6%) and −74 to +43, respectively. The correlation obtained was 0.988 with a similarity of 97.9%. Between laboratory variation data was very good with %CV below 10%.Conclusion:The introduction of dry reagents permits the elimination of cold‐chain transportation and the on‐site refrigerated storage without compromise to assay quality. The substitution of dry reagents facilitates easier supply management practice that will assure wider access to quality HIV treatment. © 2009 Clinical Cytometry Society
Synthesis, X‐ray Crystal Structures, DNA Binding and Nuclease Activities of Two Novel 1,2,4‐Triazole‐Based CuII Complexes
Authors: Li Dong‐Dong , Tian Jin‐Lei , Gu Wen , Liu Xin , Yan Shi‐Ping 
Published: October 2009

AbstractTwo novel 1,2,4‐triazole‐based copper(II) complexes have been synthesized and structurally characterized by X‐ray crystallography: [Cu2LCl3]·0.5[CuCl4]·EtOH (1) and [Cu2LBr3]·Br·H2O (2) (L = 3,5‐bis{[bis(2‐methoxyethyl)amino]methyl}‐4H‐1,2,4‐triazol‐4‐amine). Single‐crystal diffraction reveals that the two Cu atoms have a distorted octahedral geometry for 2, but one Cu atom is in a distorted square‐pyramidal environment and the other one is in a distorted octahedral environment for 1 because of the different bridged halogen atoms. The interactions of the two complexes with calf thymus DNA (CT‐DNA) have been investigated by UV absorption, fluorescence spectroscopy, circular dichroism spectroscopy, viscosity measurements and cyclic voltammetry. The apparent binding constant (Kapp) values for complexes 1 and 2 are 2.98 × 106 and 4.05 × 106 M–1. Furthermore, both the compounds display efficient oxidative cleavage of supercoiled DNA in the presence of external agents. The rate constants for the conversions of supercoiled to nicked DNA are 4.38 × 10–4 s–1 (for 1) and 5.26 × 10–4 s–1 (for 2). (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2010)
Asymmetric Synthesis of ES‐285, an Anticancer Agent Isolated from Marine Sources
Authors: Allepuz Ana C. , Badorrey Ramón , Díaz‐de‐Villegas María D. , Gálvez José A. 
Published: October 2009

AbstractThe asymmetric synthesis of (2S,3R)‐2‐amino‐3‐octanedecanol hydrochloride (ES‐285·HCl) was achieved in eight steps in ca. 38 % overall yield from the N‐benzylimine‐derived from (R)‐2,3‐O‐isopropylidene glyceraldehyde, which is easily available on gram scale from the inexpensive precursor D‐mannitol. Highly diastereoselective addition of methylmagnesium bromide to the N‐benzylimine was the key step to create the vic‐amino alcohol moiety with the appropriate configuration. Regioselective ring opening of an intermediate aminoepoxide enabled the introduction of the long hydrocarbon chain at C4.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)
Synthesis of Thioesters by Simultaneous Activation of Carboxylic Acids and Alcohols Using PPh3/NBS with Benzyltriethylammonium Tetrathiomolybdate as the Sulfur Transfer Reagent
Authors: Gopinath Purushothaman , Vidyarini Ravindran Sasitha , Chandrasekaran Srinivasan 
Published: October 2009

AbstractA new and simple route for the synthesis of thioesters starting from carboxylic acids and alcohols is reported by using tetrathiomolybdate as the key sulfur transfer reagent. Triphenylphosphane and N‐bromosuccinimide were used for the activation of the carboxylic acid and alcohol in the same pot followed by the transfer of sulfur from tetrathiomolybdate. Thioesters were obtained in good to moderate yields. Primary alcohols show excellent reactivity and gave good yields of the corresponding thioesters, whereas secondary alcohols gave moderate yields and tertiary alcohols were very less reactive and gave poor yields of the corresponding thioesters.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)
Drei neue fossile Hölzer der Morphogattung Primoginkgoxylon gen. nov. aus der Trias von Kenia
Authors: Süss Herbert , Rößler Ronny , Boppré Michael , Fischer Ottmar W. 
Published: October 2009

AbstractDrei permineralisierte Gymnospermenhölzer aus der Oberen Trias der Mazeras‐Formation (Duruma‐Gruppe, Mombasa‐Becken) werden beschrieben und aufgrund ihrer ginkgoalen Holzstruktur der neu errichteten Morphogattung Primoginkgoxylon gen. nov. zugeordnet (P. crystallophorum, P. muthamii, P. shimbaense). Die Kieselhölzer sind dreidimensional anatomisch erhalten und stammen aus dem fluviatil‐deltaischen Mazeras‐Sandstein, aufgeschlossen im Tal des Manolo River im Mwaluganje Community Elephant Sanctuary/Shimba‐Hills, im Südosten Kenias. Der Fundort wurde bisher nicht systematisch untersucht, erscheint jedoch sehr reich an Fossilien und verdient umfangreichere Untersuchungen wie in den Schlussbemerkungen erläutert wird. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Leaf architecture of Rhus s.str. (Anacardiaceae)
Authors: Andrés‐Hernández A. R. , Terrazas Teresa 
Published: October 2009

AbstractA comprehensive leaf architecture study of 31 species of Rhus s.str. was conducted to describe and identify characters of potential value for assessing infrageneric relationships. The first detailed leaf descriptions for Rhus subgenera are provided and show that cleared leaves revealed craspedodromous, eucamptodromous, and cladodromous venation types in the species studied. There was a diversity of terminal idioblasts associated with free simple or branched veinlets, and a unique combination of leaf organization, venation type, terminal idioblasts, and crystals allowed identification of subgenera and sections. Within the genus, species with toothed deciduous compound leaves exhibit a tendency to mostly craspedodromous venation with weakly sclerified tertiary veins and poorly developed terminal idioblasts; species with simple or compound evergreen leaves show mostly eucamptodromous and cladodromous venation with sclerified bundle sheath cells towards fifth‐order veins and well‐developed terminal idioblasts. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Detecting rare variants for complex traits using family and unrelated data
Authors: Zhu Xiaofeng , Feng Tao , Li Yali , Lu Qing , Elston Robert C. 
Published: October 2009

AbstractLarge genome‐wide association studies (GWAS) have been performed to detect common genetic variants involved in common diseases, but most of the variants found this way account for only a small portion of the trait variance. Furthermore, candidate gene‐based resequencing suggests that many rare genetic variants contribute to the trait variance of common diseases. Here we propose two designs, sibpair and unrelated‐case designs, to detect rare genetic variants in either a candidate gene‐based or genome‐wide association analysis. First we show that we can detect and classify together rare risk haplotypes using a relatively small sample with either of these designs, and then have increased power to test association in a larger case‐control sample. This method can also be applied to resequencing data. Next we apply the method to the Wellcome Trust Case Control Consortium (WTCCC) coronary artery disease (CAD) and hypertension (HT) data, the latter being the only trait for which no genome‐wide association evidence was reported in the original WTCCC study, and identify one interesting gene associated with HT and four associated with CAD at a genome‐wide significance level of 5%. These results suggest that searching for rare genetic variants is feasible and can be fruitful in current GWAS, candidate gene studies or resequencing studies. Genet. Epidemiol. 34: 171–187, 2010. © 2009 Wiley‐Liss, Inc.
Sediment budget of the Napo River, Amazon basin, Ecuador and Peru
Authors: Laraque A. , Bernal C. , Bourrel L. , Darrozes J. , Christophoul F. , Armijos E. , Fraizy P. , Pombosa R. , Guyot J. L. 
Published: October 2009

AbstractThe upstream‐downstream sediment budget along the Napo River (100 520 km2, 6300 m3 s−1) was studied in the Andean foothills of Ecuador, at the west of the Amazon basin. A comparative study was made during four hydrological cycles (2001–2005) for three hydrological stations located upstream, and during one hydrological cycle (2004–2005) for the fourth one located near the mouth of the Napo River (region of Iquitos in Peru). This analysis showed an unusual increase in the concentration of suspended sediment recorded for the western part of the Amazon plain. Like the runoff (81 l s−1 km2), which is a world's maximum, the erosion rate (1160 t km−2 year−1, i.e. 47% of total suspended solid (TSS) export at the exit of Ecuador), one of the highest for a floodplain basin is the result of a stepper slope than in the rest of the Andean foothills, where typically sedimentation phenomena are predominant, and can be explained in part by a greater tectonic activity. Similar phenomenes were evidenced in small mountainous rivers in New Guinea (Milliman and Syvitski, 1992; Milliman, 1995).On the headwaters of the Napo River drainage basin, the tectonic uplift causes the Pastaza Megafan's existence. This progressively diverts the course of Napo River towards north and also provokes the remobilization of fine fluvial deposits. Moreover, this geodynamic trend is completed by the impact of volcanic eruption, earthquakes and landslides. The combination of these phenomena, so common in the region, has provided a large sediment transfer, not only at present but also in the past, as can be confirmed by the presence of incised terraces, mainly formed by volcanic materials.Then, these results were compared with a similar study carried out further south in the Madeira basin at the Bolivian foothills. These studies show the spatio‐temporal variability of the relation between sediment transfer and geodynamic processes at the Andean Piedmont. Copyright © 2009 John Wiley & Sons, Ltd.