bluuebunny/crossref_metadata_2025_split huggingface dataset:
Computational Study of Cage Like (ZnO)12 Cluster Using Hybrid and Hybrid Meta Functionals
Authors: Flores‐Hidalgo Manuel Alberto , Glossman‐Mitnik Daniel , Galvan D. H. , Barraza‐Jimenez Diana 
Published: April 2013

AbstractDensity Functional Theory employing hybrid and M06 functionals in combination with three different basis sets is used to calculate the ground state of a cage like (ZnO)12 nanocluster which has been consistently reported as the more stable cluster for its particular size. B3LYP and B3PW91 hybrid functionals combined with 6‐31+G*, Lanl2dz and SDD basis sets are employed to treat the ZnO molecular system. Alternatively, three M06 functionals in combination with three basis sets are employed in the nanostructure calculations. Results obtained by treating ZnO sodalite cage nanocluster with M06 functionals demonstrated comparable quality to results obtained with hybrid functionals. Within this study, efficient theoretical DFT methods with the widely known hybrid and the recently created M06 meta‐hybrid functionals are employed to study nanostructured ZnO. Our resulting parameters provide a fresh approach performance wise on the different theoretical methods to treat transition metal nanostructures, particularly, ZnO nanoclusters geometry and electronic structure.
Rapid Preparation of Monolithic Molecular Imprinted Polymer Fiber for Solid Phase Microextraction by Microwave Irradiation
Authors: Jin Ya‐Feng , Chen Na , Liu Run‐Qiang , Zhang Yu‐Ping , Bai Lian‐Yang , Chen Jun 
Published: April 2013

AbstractIn this paper, a simple, fast and in situ polymerization strategy to prepare monolithic molecularly imprinted polymer (MIP) fibers for solid phase microextraction (SPME) is developed using silica capillaries as molds. With the help of microwave irradiation, polymerization was carried out in 5.5 min using olivetol as a template molecular, α‐methacrylic acid (MAA) as a functional monomer and ethylene dimethacrylate (EDMA) as a crosslinker, toluene and dodecanol as the binary porgens. The resulted MIP fibers were finally obtained after silica being etched away with a controlled length, and subsequently characterized by scanning electron microscope (SEM) and Fourier transform infrared absorption spectroscopy (FT‐IR). Under the optimal extraction conditions, a simple method based on the coupling of MIP SPME with high performance liquid chromatography (HPLC) was used for the selective determination of the model mixtures of olivetol, phenol and m‐toluidine in lake water and wheat bran samples. The recoveries of olivetol, phenol and m‐toluidine for both samples were in the range of 87.3‐93.6%, 21.4‐27.2%, 18.9‐24.8% at three spiked levels, respectively, demonstrating that higher extraction and the specific absorption occurred between the template molecule and the prepared MIP fiber.
NaBH4/DOWEX(R)50WX4: A Convenient Reducing System for Fast and Efficient Reduction of Carbonyl Compounds to Their Corresponding Alcohols
Authors: Setamdideh Davood , Karimi Zahra , Alipouramjad Avat 
Published: April 2013

AbstractThe reduction of a variety of carbonyl compounds was efficiently carried out with NaBH4/DOWEX(R)50WX4 system. The reactions were performed to give the corresponding alcohols derivatives in perfect yields in THF at room temperature. Reduction of acyloins and a‐diketones by this reducing system produced efficiently the corresponding vicinal diols. Also, the reduction of aldehydes over ketones has been accomplished successfully by this system. Regioselectivity of this system was also investigated with exclusive 1,2‐reduction of conjugated carbonyl compounds to their corresponding allylic alcohols in high to excellent yields.
A strategy for efficient immobilization of laccase and horseradish peroxidase on single‐walled carbon nanotubes
Authors: Li Ying , Huang Xirong , Qu Yinbo 
Published: April 2013

AbstractBACKGROUNDThe immobilization of biomacromolecules on carbon nanotubes has attracted considerable attention. Based on the specific affinity between concanavalin A (Con A) and glycosyl, and the ability of alkyl polyglucoside to disperse single‐walled carbon nanotubes (SWNTs), a new self‐assembly immobilization strategy is developed.RESULTSUsing laccase (Lac) and horseradish peroxidase (HRP) as models, it is demonstrated that this new self‐assembly immobilization strategy has obvious advantages over the direct adsorption immobilization strategy in enzyme loadings ( 1.34‐fold (Lac) and 1.46‐fold (HRP) higher) and in the specific activity ( 5.06‐fold (Lac) and 4.77‐fold (HRP) higher). Circular dichroism (CD) spectra and fluorescence spectra also indicate that the present new indirect immobilization strategy has less impact on the enzyme conformation compared with the direct adsorption strategy. For the catalytic oxidation of dibenzothiophene (DBT), the immobilized HRP prepared using the present self‐assembly strategy was more effective than that using the direct adsorption strategy.CONCLUSIONBased on these findings, it is concluded that the present self‐assembly strategy can greatly improve the enzymatic properties of the immobilized enzymes. © 2013 Society of Chemical Industry
EFFECTS OF ACUTE AND CHRONIC MORPHINE ON DELAY DISCOUNTING IN PIGEONS
Authors: Eppolito Amy K. , France Charles P. , Gerak Lisa R. 
Published: April 2013

AbstractWhen reinforcers of different magnitudes are concurrently available, choice is greater for a large reinforcer; that choice can be reduced by delaying its delivery, a phenomenon called delay discounting and represented graphically by a delay curve in which choice is plotted as a function of delay to the large reinforcer. Morphine, administered acutely, can alter responding for large, delayed reinforcers. In this study, the impact of morphine tolerance, dependence and withdrawal on choice of delayed reinforcers was examined in six pigeons responding to receive a small amount of food delivered immediately or a larger amount delivered immediately or after delays that increased within sessions. Acutely, morphine decreased responding for the large reinforcer, and the effect was greater when morphine was administered immediately, rather than 6 hr, before sessions. During 8 weeks of daily administration, morphine produced differential effects across pigeons, shifting the delay curve downward in some and upward in others. In all pigeons, tolerance developed to the response‐rate‐decreasing effects of morphine but not to its effects on delay discounting. When chronic morphine treatment was discontinued, rate of responding decreased in four pigeons, indicating the emergence of withdrawal; choice of the large reinforcer increased, regardless of delay, in all pigeons, an effect that persisted for weeks. These data suggest that chronic morphine administration has long‐lasting effects on choice behavior, which might impact vulnerability to relapse in opioid abusers.
Influence of bed patchiness, slope, grain hiding, and form drag on gravel mobilization in very steep streams
Authors: Scheingross Joel S. , Winchell Eric W. , Lamb Michael P. , Dietrich William E. 
Published: April 2013

AbstractSteep streams are a major portion of channel networks and provide a link to transport sediment from hillslopes to lower gradient rivers. Despite their importance, key unknowns remain, perhaps foremost of which is evaluating in steep streams empirical laws for fluvial sediment transport developed for low‐gradient rivers. To address this knowledge gap, we painted sediment in situ over 3 years to monitor incipient sediment motion and sediment‐patch development in five small (drainage areas of 0.04–2 km2) and steep (slopes of 5–37%) tributaries of Elder Creek, California, United States. We found that channel beds organized into size‐sorted sediment patches which displayed active fluvial transport of gravel annually, consistent year‐to‐year patch median grain sizes, partial transport of bed material, and significantly higher values of critical Shields stress for incipient sediment motion compared to that observed for lower gradient rivers. The high critical Shields stresses (up to ≈0.5 for the median grain size) agree within a factor of ~3 to theoretical predictions which account for slope‐dependent hydraulics, grain hiding, and sediment patches. For grains of approximately the same size as the roughness length scale, slope‐dependent hydraulics and bed patchiness are the dominant controls on critical Shields stress values, while grain hiding is important for grains larger or smaller than the roughness length scale. Form drag exists in our monitored tributaries but has a smaller influence than the above effects. Our field observations show fluvial processes contribute to sediment mobilization in steep channels which are often considered to be dominated by debris flows.
Reduction of hexavalent chromium by a novel Ochrobactrum sp. – microbial characteristics and reduction kinetics
Authors: Narayani M. , Vidya Shetty K. 
Published: April 2013

AbstractA Gram negative hexavalent chromium (Cr(VI)) reducing bacteria, Ochrobactrum sp. Cr‐B4 (genbank accession number: JF824998) was isolated from the aerator water of an activated sludge process of a wastewater treatment facility of a dye and pigment based specialty chemical industry. It showed a resistance for 1000 mg L−1 Cr(VI). It exhibited resistance against other heavy metal ions like Ni2+ (900 mg L−1), Cu2+ (500 mg L−1), Pb2+ (800 mg L−1), and Cd2+(250 mg L−1), Zn2+ (700 mg L−1), Fe3+ (800 mg L−1), and against selected antibiotics. Cr‐B4 could efficiently reduce 200 mg L−1 Cr(VI) completely in nutrient and LB media and could convert Cr(VI) to Cr(III) efficiently. Cr(VI) reduction in nutrient media followed allosteric enzyme kinetics with Km values of 59.39 mg L−1 and Vmax values of 47.03 mg L−1 h−1. The reduction in LB media followed Michaelis–Menten kinetics with Km values of 99.52 mg L−1 and Vmax of 77.63 mg L−1 h−1. Scanning electron micrograms revealed the presence of extracellular polymeric secretions.
pH‐dependent effect of pectinase secretion in Penicillium griseoroseum recombinant strains
Authors: Teixeira Janaina Aparecida , Corrêa Thamy Lívia Ribeiro , de Queiroz Marisa Vieira , de Araújo Elza Fernandes 
Published: April 2013

AbstractA number of parameters, including culture medium pH, affect growth and enzyme production by microorganisms. In the present study, the production and secretion of pectin lyase (PL) and polygalacturonase (PG) by recombinant strains of Penicillium griseoroseum cultured in mineral‐buffered media (MBM; initial pH 6.8) and mineral‐unbuffered medium (MUM; initial pH 6.3) were evaluated. Under these culture conditions, no change in the transcriptional levels of plg1 and pgg2 was observed. However, the levels of secreted total protein ranged from 7.80 ± 1.1 to 3.25 ± 1.50 µg ml−1 in MBM and MUM, respectively, and were evaluated by SDS–PAGE. PL and PG enzymatic activities decreased 6.4 and 3.6 times, respectively, when P. griseoroseum was cultivated under acidic pH conditions (MUM). Furthermore, differences were observed in the hypha and mycelium morphology. These findings suggest that acidic growing conditions affect PL and PG secretion, even though the transcription and translation processes are successful. The data obtained in this study will help to establish optimal culture conditions that increase production and secretion of recombinant proteins by filamentous fungi.
Environmentally safe treatment of black liquor with Comamonas sp. B‐9 under high‐alkaline conditions
Authors: Zheng Yu , Chai Liyuan , Yang Zhihui , Chen Yuehui , Shi Yan , Wang Yangyang 
Published: April 2013

AbstractThe strain Comamonas sp. B‐9 was isolated from steeping fluid of erosive bamboo slips derived from Kingdom Wu during the Three‐Kingdoms Dynasty of ancient China (A.D. 220–280). It could be used to treat black liquor (BL) with high‐alkaline pH and with an initial chemical oxygen demand (COD) of 18,000–25,000 mg L−1, without the addition of other carbon and nitrogen sources. The results revealed that Comamonas sp. B–9 was capable of reducing the COD, color, and lignin content of BL by up to 56.8, 35.3, and 43.5%, respectively. High levels of laccase, manganese peroxidase, cellulase, and xylanase enzymatic activities were also observed, and these enzymes could play an important role in the biotreatment of BL. Further, GC–MS analysis showed that most of the compounds detected in BL after biotreatment with Comamonas sp. B‐9 were diminished, while 4‐methyl benzaldehyde, 3,4,5‐trihydroxybenzoic acid ethyl ester, and 4‐hydroxy‐3,5‐dimethoxy benzaldehyde were produced as metabolites. The presented results indicate that Comamonas sp. B‐9 has potential application for the treatment of wastewaters from pulp and paper processing with high COD load under high‐alkaline conditions.
Bacterial strains isolated from PCB‐contaminated sediments and their use for bioaugmentation strategy in microcosms
Authors: Dudášová Hana , Lukáčová Lucia , Murínová Slavomíra , Puškárová Andrea , Pangallo Domenico , Dercová Katarína 
Published: April 2013

AbstractThis study was focused on the characterization of 15 bacterial strains isolated from long‐term PCB‐contaminated sediment located at the Strážsky canal in eastern part of Slovakia, in the surroundings of a former PCB producer. PCB‐degrading strains were isolated and identified as Microbacterium oleivorans, Stenotrophomonas maltophilia, Brevibacterium sp., Ochrobactrum anthropi, Pseudomonas mandelii, Rhodococcus sp., Achromobacter xylosoxidans, Stenotrophomonas sp., Ochrobactrum sp., Pseudomonas aeruginosa, and Starkeya novella by the 16S rRNA gene sequence phylogenetic analysis. This study presents a newly isolated bacterial strain S. novella with PCB‐degrading ability in liquid medium as well as in sediment. For A. xylosoxidans, the bphA gene was identified. The best growth ability in the presence of all sole carbon sources (biphenyl and PCBs vapor) was obtained for Ochrobactrum sp. and Rhodococcus sp. Uncultured Achromobacter sp. showed the highest potential for bioaugmentation of PCB‐contaminated sediment.
Evaluation of hydroxylamine oxidoreductase as a functional and phylogenetic marker to differentiate Nitrosomonas spp.
Authors: Keluskar Radhika , Desai Anjana 
Published: April 2013

AbstractNitrosomonas genus belongs to beta‐subclass of Proteobacteria and encompasses closely related species. Sequence independent techniques like single strand confirmation polymorphism (SSCP) was attempted in the present study to resolve AOB using ammonia monooxygenase (amoA) and hydroxylamine oxidoreductase (hao) gene fragments, unique to AOB. Variation in hydroxylamine oxidoreductase (HAO) enzyme zymogram of isolates observed in the study was also explored as an additional sequence independent method to substantiate the observations. Nitrosomonas europaea (standard strain) and 12 isolates, obtained by enriching environmental samples, were differentiated into six and four groups by SSCP analyses of amoA and hao gene fragments, respectively, whereas they could be resolved into six distinct groups through activity staining of HAO enzyme. amoA gene fragment was therefore found to be better than hao gene fragment in resolving the studied AOB based on richness and evenness with Simpson's index of diversity – 0.85. However, the ensembled use of these molecular methods (SSCP of amoA and hao gene fragments) and HAO enzyme zymogram in fingerprinting AOB provide better resolution and evenness, contributing significantly in AOB diversity studies. Grouping of AOB isolates by hao gene SSCP analysis followed almost the same pattern as that by 16S rRNA gene based sequence analysis, hence it is suitable as a phylogenetic marker.
Bacillus amyloliquefaciens Q‐426 as a potential biocontrol agent against Fusarium oxysporum f. sp. spinaciae
Authors: Zhao Pengchao , Quan Chunshan , Wang Yingguo , Wang Jianhua , Fan Shengdi 
Published: April 2013

AbstractIn recent years, Bacillus species have received considerable attention for the biological control of many fungal diseases. In this study, Bacillus amyloliquefaciens Q‐426 was tested for its potential use against a variety of plant pathogens. Our screen for genes involved in the biosynthesis of antifungal agents revealed that the fen and bmy gene clusters are present in the Q‐426 genome. Lipopeptides such as bacillomycin D, fengycin A, and fengycin B were purified from the bacterial culture broth and subsequently identified by ESI‐mass spectrometry. The minimal inhibitory concentration of fengycin A against Fusarium oxysporum f. sp. spinaciae W.C. Snyder & H.N. Hansen O‐27 was determined to be 31.25 μg ml−1. However, exposure of fungal cells to 50 μg ml−1 of fengycin A did not allow permeation of fluorescein diacetate into the cytoplasm through the cell membrane. Moreover, leakage of intracellular inorganic cations, nucleic acid and protein were also not detected, indicating that the fungal cell membrane is not the primary target of action for fengycin A. Profound morphological changes were observed in the F. oxysporum strain and spore germination was completely inhibited, suggesting that 50 μg ml−1 of fengycin A acts, at least, as a fungistatic agent.
In vitro evaluation of nematophagous activity of fungal isolates
Authors: Nicola Lidia , Tosi Solveig , Savini Dario 
Published: April 2013

AbstractFour filamentous fungi associated with nematodes were isolated and identified from litter samples collected in the Integral Natural Reserve “Bosco Siro Negri” (PV, Italy): Arthrobotrys dactyloides, Arthrobotrys oligospora var. oligospora, Pochonia bulbillosa, and Pochonia chlamydosporia var. catenulata. Their capacity to break down the nematode population was evaluated in vitro by means of simple and reproducible multiwell plates method. All fungal strains were able to cause a death‐rate significantly different from the controls (p < 0.05). Precisely, A. dactyloides caused, on average, a 26% death rate increase in the nematode population compared to the control, A. oligospora var. oligospora 25%, P. bulbillosa 12%, and P. chlamidosporia var. catenulata 17%. The method has also allowed to determine the more active fungi as regards the prey's life cycle stage. The most active strains against nematodes (adults) were A. dactyloides and A. oligospora var. oligospora, known to attack adults or larval stages by means of tridimensional traps. On the contrary P. bulbillosa and P. chlamydosporia, known to attack mainly the nematode life stage of cysts, showed lower activity against adult nematodes.
Wet‐plate culture studies of Penicillium sp. PT95 and Q1 for mass production of sclerotia
Authors: Zhao Wen‐Jing , An Cui‐Hong , Han Jian‐Rong 
Published: April 2013

AbstractPenicillium sp. PT95 and Q1 strains were able to form abundant orange, sand‐shaped sclerotia in which carotenoids were accumulated. To determine the potential availability of the wet‐plate method for mass production of sclerotia, nine kinds of liquid media were used culture the PT95 and Q1 strains. The results of the wet‐plate culture showed that on 25% glycerol nitrate broth medium, the growth of both strains was relatively slow, and no sclerotia were found. Q1 strain cultured on Czapek's yeast extract broth medium could not form sclerotia. On other media, both strains could form sclerotia. For PT95 strain, the highest sclerotial biomass (380 mg plate−1) and carotenoids yield (20.88 µg plate−1) could be obtained on Czapek's yeast extract broth and Georgiou's liquid medium, respectively. For Q1 strain, malt extract broth medium gave the highest sclerotial biomass (340 mg plate−1) and omitting iron Joham's liquid medium gave the highest carotenoids yield (18.29 µg plate−1). The results from this study suggest the potential usage of wet‐plate method in the mass production of sclerotia of the PT95 and Q1 strains.
Screening and production of a potent extracellular Arthrobacter creatinolyticus urease for determination of heavy metal ions
Authors: Ramesh Rajendran , Aarthy Mayilvahanan , Gowthaman Marichetti Kuppuswami , Gabrovska Katya , Godjevargova Tzonka , Kamini Numbi Ramudu 
Published: April 2013

AbstractThis paper describes the isolation of a potent extracellular urease producing microorganism, identified by 16S rRNA as Arthrobacter creatinolyticus MTCC 5604 and its medium optimization by classical one‐factor‐at‐a‐time method and central composite rotatable design (CCRD), a tool of response surface methodology (RSM). An optimal activity of 9.0 U ml−1 was obtained by classical method and statistical optimization of the medium resulted in an activity of 17.35 U ml−1 at 48 h and 30 °C. This activity was 4.91 times greater than the initial activity (3.53 U ml−1) from the basal medium and the enzyme showed maximum activity at pH 8.0 and 60 °C and was stable at pH 7.0–9.0 and temperatures up to 50 °C. Furthermore, the enzyme was assessed for its activity reduction by determining the inhibitory concentration (IC50) of heavy metal ions and the inhibition of urease was in the order of Cu(II) > Cd(II) > Zn(II) > Ni(II). Urease was highly sensitive to Cu(II) and its inhibition was 94% and 100% in model solutions containing a mixture of Cu(II) with heavy metal ions Cd(II) and Zn(II), respectively. The results of these studies suggested that the enzyme could be utilized as sensors to determine the levels of Cu(II) ions in industrial effluents, contaminated soil and ground water.
Climatological analysis of December rainfall in the Panama Canal Watershed
Authors: Murphy Michael J. , Georgakakos Konstantine P. , Shamir Eylon 
Published: April 2013

ABSTRACTMonthly accumulated precipitation over the tropical Panama Canal Watershed has the largest interannual variability in December, with the wettest month on record being December 2010. December accumulated precipitation over the watershed is found to vary with sea surface temperature (SST) anomalies in both the tropical North Atlantic and equatorial Pacific oceans, but a considerably stronger relationship is found with the difference between these SST anomalies. The configuration of SST anomalies in these two ocean basins during December has a strong effect on the flux of low‐level moisture over the Caribbean Sea, southern Central America, and the eastern Pacific Ocean through the modification of the Caribbean Low‐Level Jet (CLLJ) and the Chorro del Occidente Colombiano (CHOCO) jet. Wet Decembers in the watershed are associated with cool (warm) SST anomalies in the tropical Pacific (North Atlantic), a weakening (strengthening) of the CLLJ (CHOCO jet), and increased moisture convergence over and around Panama, with the opposite conditions associated with dry Decembers. The SST anomalies in these two ocean basins affect the distribution of daily precipitation during December differently, with SST anomalies in the Pacific (Atlantic) predominately associated with changes in the frequency of heavier (lighter) precipitation. The analysis shows that December 2010 followed the pattern of associations of wet Decembers but with the highest intensity of precipitation and CHOCO jet strength.