bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effects of toxic cyanobacteria and purified toxins on the survival and feeding of a copepod and three species of Daphnia
Authors: DeMott William R. , Zhang Qing‐Xue , Carmichael Wayne W. 
Published: April 2010

Acute toxicity experiments with purified toxins show that four species of zooplankton differ markedly in their physiological sensitivity to cyclic peptide hepatotoxins from Microcystis aeruginosa (microcystin‐LR) and Nodularia spumigena (nodularin). The copepod Diaptomus birgei was most sensitive (48‐h LC50 for microcystin‐LR ranged from 0.45 to 1.00 µg ml‒1), Daphnia pulicaria was least sensitive (48‐h LC50, 21.4 µg ml‒1), and Daphnia hyalina (48‐h LC50, 11.6 µg ml‒1) and Daphnia pulex (48‐h LC50, 9.6 µg ml‒1) were intermediate in sensitivity.Survivorship in the presence of toxic Microcystis was strongly influenced by both physiological sensitivity and feeding behavior. Relatively good survivorship by D. pulicaria was associated with low sensitivity to purified toxin and rapid feeding inhibition in the presence of toxic cells. In contrast, very poor survivorship by D. pulex was associated with greater physiological sensitivity and nearly uninhibited feeding on toxic Microcystis. Intermediate survivorship by D. birgei was associated with food selection capabilities on the one hand and high physiological sensitivity and uninhibited feeding on the other. Our results suggest that zooplankton have evolved both physiological and behavioral adaptations which enhance their abilities to coexist with toxic cyanobacteria.
Degradation and elemental release rates from phytoplankton debris and their geochemical implications
Authors: Byeong‐Gweon Lee , Fisher Nicholas S. 
Published: April 2010

The diatom Thalassiosira pseudonana was held without nutrients in the dark for 22 d; release rates of carbon and seven metals from the cells were determined with radiotracers. Cellular C was lost faster at 18°C (3.6% d−1) than at 4°C (1.0% d−1) due to higher microbial activity at 18°C. C loss rates decreased (from 9.7% d−1 at 18°C and 2.1% d−1 at 4°C) after 7 d. Formalin (24 mM) and HgCl2 (0.9 mM) inhibited microbial activity as indicated by 14CO2 evolution; NaN3 (154 mM) was less effective. Poison‐treated cells leached 33–39% of their C (as DOC) and large quantities of Cd, Se, Zn, and Ag.Cd, Se, and Zn, primarily in a soluble fraction in the cells, were released at about the same rate as C and were affected by microbial activity and temperature. In contrast, Ag, Am, Ce, and Co were retained to a much greater extent by the decomposing cells, their release was slower than that of C, and temperature and microbial activity had negligible effects on their retention. The results suggest that Cd, Se, and Zn will be rapidly recycled from planktonic debris in surface waters, while Ce, Am, Ag, and Co will be transported by phytoplankton aggregates sinking from surface waters.
Mixing and Blending
Authors: Dickey David S. 
Published: April 2010

AbstractMixing and blending are processes by which fluids, powders, and gases are made more homogeneous or more uniformly dispersed. Mixing is difficult to categorize, because of the many possible combinations and applications. Often the phases present: liquids, solids, gases, or combinations, will describe the mixing characteristics or suggest intensity requirements. In the process industries, a mixing step may be the critical one that converts raw materials into products. Most chemical reactions, many biological processes, nearly all formulations, and many physical conversions involve some type of mixing operation. Besides being called mixing, terms like agitation, blending, and stirring are used as both general and specific descriptions of related operations. Mixing and agitation are most often used in the context of fluid or powder motion. Mixing or blending may refer more specifically to the combination of different materials. The broad use of mixing processes and equipment can be found in many chemical applications.
Resins, Natural
Authors: Class Jay B. 
Published: April 2010

AbstractNatural resins are solid, amorphous, usually transparent or translucent organic substances that originate from plant secretions. They may be obtained directly as tree or plant extrudates. Shellac is refined from insect secretions. These resins may be altered by methods of isolation or modified in production to increase their industrial utility. Rosin and rosin derivatives are commercially the most important commercial resins. The isolation of rosin from natural resources is discussed as well as properties, composition, chemical reactions, and derivatives. China is the largest producer of rosin and derivatives. Rosin and modified rosins are used in the paper‐making industry as a sizing agent, in ink, adhesives, as a glazing agent, in soap,and in soldering. Traditional natural resins, such as dammar resins, copal, and amber are also discussed. The history, cultivation, production, and composition of shellac are detailed. Shellac is used as a protective coating in the food and pharmaceutical industries. Synthetic resins have replaced shellac in some markets.
Tungsten Compounds
Authors: Penrice Thomas W. 
Published: April 2010

AbstractTungsten combines with many other elements to form simple stable compounds. It readily polymerizes, but the chemistry of aqueous solutions is very complex. The chemical uses of tungsten have increased. The compounds discussed fall into the following categories: hexacarbonyl; halides and oxyhalides; sulfides; and interstitial compounds. Properties and uses of these compounds are discussed. Some important compounds,eg, are the halides, which are useful as starting materials in the chemical vapor deposition of tungsten; the oxides are intermediates in the stepwise reduction in hydrogen to metal; ammonium paratungstate (APT) is of commercial significance because it is the precursor of high purity tungsten oxides, tungsten, and tungsten carbide powders. APT is the most widely traded primary tungsten material. More than half of tungsten production is for the preparation of tungsten carbide. The carbides are widely used in the manufacture of hard carbides for high speed machining tools, drill bits, turning tools, etc. Soluble tungsten compounds show varying degrees of toxicity, exposures in the workplace are regulated. In general, tungsten compounds are used to make catalysts, corrosion‐resistant coatings, dyes and pigments, fire‐resistant compounds, lubricants, phosphor, and semiconductors.
The Organic Thermochemistry of Hydroxylamines, Oximes, Hydroxamic Acids and their Derivatives
Authors: Slayden Suzanne W. , Liebman Joel F. 
Published: April 2010

AbstractIntroduction: Scope of the Chapter, Definitions of Key Terms and Sources of DataHydroxylamines andN‐Substituted DerivativesO‐Substituted Hydroxylamine Derivatives (Alkoxylamines)MonooximesGlyoxime and Other DioximesQuinone Oximes and NitrosoarenolsOxime EthersHydroxamic Acids and their Derivatives
Synthesis of Hydroxylamines
Authors: Melman Artem 
Published: April 2010

Abstract

Introduction

Hydroxylamines through Hydrolysis of Hydroxamic Acids, Oximes and Nitrones

Synthesis of Hydroxylamines through Alkylation and Arylation of other Hydroxylamines

Hydroxylamines through Reduction Reactions

Hydroxylamines through Addition to the
C

N
Double Bond of Oximes, Oxime Ethers and Nitrones

Hydroxylamines through Addition to the
N

O
Double Bond of Nitroso and Nitro Compounds

Hydroxylamines through Oxidation of Amines

Hydroxylamines through Cycloaddition Reactions
N‐Heteroatom‐Substituted Hydroxamic Esters
Authors: Glover Stephen A. 
Published: April 2010

AbstractIntroductionUnusual Characteristics ofN‐Heteroatom‐Substituted Hydroxamic EstersN‐Alkoxy‐N‐HaloamidesN‐Acyloxy‐N‐AlkoxyamidesN,N‐DialkoxyamidesN‐Alkoxy‐N‐AminoamidesN‐Alkoxy‐N‐ThioalkylamidesAcknowledgement
Toxic Territories
Authors: Gissen David 
Published: April 2010

AbstractAs half of the world's population has become urbanised, toxic or at least previously built‐up land has become more like the norm. Guest‐editor David Gissen considers the reality for architecture of toxic territories, in which the relationship of architecture with pollution needs to shift from one in which architecture is wholly regarded as a means of separation from a noxious external environment to one of interaction. Copyright © 2010 John Wiley & Sons, Ltd.
The Aurora Project
Authors: Johnson Jason Kelly , Gattegno Nataly 
Published: April 2010

AbstractThe new opportunities for simulation and representation that computer modelling affords designers has been well charted. Jason Kelly Johnson and Nataly Gattegno of Future Cities Lab, however, are combining these new potentials with dynamic mapping and modelling methods derived from modern cartography. The most familiar of these tools is Google Earth, which provides a unique new bird's‐eye view of the earth's surface. Other geographical softwares also combine to enable the manipulation of real‐time, open‐source, user‐generated data as never before. Copyright © 2010 John Wiley & Sons, Ltd.
Mass transfer and separation criteria for high‐speed countercurrent chromatography
Authors: Zhao Chun‐Xia , He Chao‐Hong 
Published: April 2010

AbstractHigh‐speed countercurrent chromatography (HSCCC) is a versatile technique for preparative separations of a wide variety of solutes. For optimization of operating conditions, prediction of separations, and scale‐up study, a model is needed to describe the effluent concentration profile, which determines the separation efficiency (mass transfer, mixing, and partitioning) and the resolution between peaks. A transfer‐dispersive model is proposed to describe the effluent profile based on the assumption that the retention of a peak is caused by partitioning over two phases, and peak broadening is caused by axial dispersion and mass transfer limitation. In this work, mass transfer was investigated by comparing model simulations to experimental data. One generalized correlation of overall mass transfer coefficients was derived. Based on the correlations of axial dispersion coefficients in our previous work and mass transfer coefficients in this study, the model predicts the elution concentration profile well. Furthermore, separation criteria were proposed to predict the separation of two adjacent solutes, and they were verified using literature data. © 2010 American Institute of Chemical Engineers AIChE J, 2011
Synthesis and Antibacterial Activity of a Novel Series of 2,3‐Diaryl‐substituted‐imidazo(2,1‐b)‐benzothiazole Derivatives
Authors: Palkar Mahesh , Noolvi Malleshappa , Sankangoud Ramappa , Maddi Veeresh , Gadad Andanappa , Nargund Laxmi Venkat G. 
Published: April 2010

AbstractBenzothiazole and imidazole compounds are extensively studied heterocyclics due to their wide spectrum of bioactivities. Among them, the imidazo(2,1‐b)‐benzothiazole derivatives are pharmacologically important because of their immunostimulant, anti‐inflammatory, antifungal, antimicrobial, antitumor, and other activities. In the present research work, a novel series of 2,3‐diaryl‐substituted imidazo(2,1‐b)‐benzothiazoles 13a–o have been synthesized by reaction of substituted 2‐aminobenzothiazoles 1–8 and an appropriately substituted α‐bromo‐1‐(4′′‐substituted)‐phenyl‐2‐(4′‐substituted)‐phenyl‐1‐ethanones 9–12 in the presence of anhydrous acetonitrile. They were characterized by physicochemical, elemental, and spectral (IR, 1H‐NMR, and Mass) data. All the synthesized compounds were screened for their in‐vitro antibacterial activity against Gram‐positive, Gram‐negative bacteria. The investigation of antibacterial screening data revealed that most of the compounds tested have demonstrated congruent activity against Staphylococcus aureus, Bacillus subtilis, Escherichia coli, and Pseudomonas aeruginosa as compared with the standard ampicillin. Among the series, compounds 13d, 13h, and 13m exhibited excellent an antibacterial activity profile as compared with the standard. In summary, preliminary results indicate that some of the newly synthesized title compounds exhibited promising antibacterial activities and they warrant more consideration as prospective antimicrobials.
Hydrogen‐Bonding Induced Cooperative Effect on the Energy Transfer in Helical Polynorbornenes Appended with Porphyrin‐Containing Amidic Alanine Linkers
Authors: Liu Zhi‐Chang , Chen Chih‐Hsien , Wang Hsian‐Wen , Huang Yen‐Chin , Kao Ming‐Jui , Lim Tsong‐Shin , Luh Tien‐Yau 
Published: April 2010

AbstractPolynorbornenes appended with porphyrins containing a range of different linkers are synthesized. The use of bisamidic chiral alanine linkers between the pending porphyrins and the polymeric backbone has been shown to bring the adjacent porphyrin chromophores to more suitable orientation for exciton coupling owing to hydrogen bonding between the adjacent linkers. The hydrogen bonding between the adjacent pendants in these polymers may induce a cooperative effect and therefore render single‐handed helical structures for these polymers. Such a cooperative effect is reflected in the enhancement of FRET efficiencies between zinc–porphyrin and free base porphyrin in random copolymers.
Dimeric Capsules Formed by Tetra‐CMPO Derivatives of (Thia)Calix[4]arenes
Authors: Rudzevich Valentyn , Kasyan Oleg , Drapailo Andriy , Bolte Michael , Schollmeyer Dieter , Böhmer Volker 
Published: April 2010

AbstractThiacalix[4]arene 2, calix[4]arene 3 a and its tetraether fixed in the cone conformation 3 b form homo‐ and heterodimeric capsules in apolar solvents, which are held together by a seam of NH⋅⋅⋅O=P hydrogen bonds between carbamoylmethyl phospine oxide functions attached to their wide rim. Their internal volume of ∼370 Å3 requires the inclusion of a suitable guest. Although neutral molecules such as adamantane (derivatives) or tetraethylammonium cations form kinetically stable complexes (1H‐ and 31P‐time scale), the included solvent is rapidly exchanged. The internal mobility of the included tetraethylammonium cation is distinctly higher (ΔG=42.5 and 49.7 kJ mol−1 for 3 a and 3 b) than that for similar capsules of tetraurea calix[4]arenes 1. Mixtures of 1 with 2, 3 a, or 3 b contain only the two homodimers but the heterodimerization occurs with the tetraloop tetraurea 6, which cannot form homodimers. Two dimers with cationic guests (2⋅(C5H5)2Co+⋅2 and 3 a⋅Et3NH+⋅H2O⋅3 a) were confirmed by single‐crystal X‐ray analysis.
Dendrimers: A Mimic Natural Light‐Harvesting System
Authors: Zeng Yi , Li Ying‐Ying , Chen Jinping , Yang Guoqiang , Li Yi 
Published: April 2010

AbstractIn natural photosynthetic systems, a large array of chlorophyll molecules surrounds a single reaction center and channels the absorbed solar energy to the reaction center, ultimately resulting in ATP production. Dendrimers are well‐defined tree‐like macromolecules having numerous chain ends all emanating from a single core, which makes them an attractive candidate for light‐harvesting applications. More importantly, their synthesis is controllable and the accurate positioning of chromophores can be achieved. Photoinduced electron transfer and energy transfer are main processes involved in photosynthesis. Studies on these processes in dendritic systems are important for the future application of dendrimers in optoelectronic devices. In this Focus Review we will discuss recent advances of light‐harvesting dendrimers and emphasize the energy transfer and electron transfer characteristics in these systems.
An HPLC assay for the lipophilic camptothecin analog AR‐67 carboxylate and lactone in human whole blood
Authors: Tsakalozou Eleftheria , Horn Jamie , Leggas Mark 
Published: April 2010

AbstractAR‐67 (7‐t‐butyldimethylsilyl‐10‐hydroxycamptothecin, DB‐67) is a camptothecin analog currently in early stage clinical trials. The lactone moiety of camptothecins hydrolyzes readily in blood to yield the pharmacologically inactive carboxylate form. However the lactone form of third‐generation lipophilic congeners, such as AR‐67, is more stable, possibly due to partitioning into red cell membranes. This prompted us to develop a reverse‐phase HPLC method with fluorescence detection (excitation 380 nm/emission 560 nm), which could quantitate the concentration of AR‐67 lactone and carboxylate in whole blood. Samples were prepared by red cell lysis, protein precipitation with methanol and centrifugation to remove denatured materials. Recovery was estimated to be >85%. Analytes were eluted isocratically with 0.15 m ammonium acetate buffer containing 10 mm TBAP (pH 6.5) and acetonitrile (65:35, v/v) on a Nova‐Pak C18 column (4 µm; 3.9 × 150 mm). The assay was linear in the ranges 0.5–300 and 2.5–300 ng/mL for carboxylate and lactone, respectively. Accuracy and precision were acceptable. AR‐67 forms were stable in whole blood and in methanolic supernatants. This assay has been successfully applied to measure AR‐67 concentrations in whole blood of patients enrolled in a phase I study. Copyright © 2010 John Wiley & Sons, Ltd.
Development and validation of a highly sensitive LC‐MS/MS method for simultaneous quantitation of nortriptyline and 10‐hydroxynortriptyline in human plasma: application to a human pharmacokinetic study
Authors: Hotha Kishore Kumar , Ravindranath L. K. , Veera K. N. Jaya , Kumar K. Kishore , Reddy Y. Ramachandra , Jagadeesh B. , Rao D. V. Narayana , Bharathi D. Vijaya , Mullangi Ramesh 
Published: April 2010

AbstractA highly sensitive and specific LC‐MS/MS method has been developed for simultaneous estimation of nortriptyline (NTP) and 10‐hydroxynortriptyline (OH‐NTP) in human plasma (250 µL) using carbamazepine as an internal standard (IS). LC‐MS/MS was operated under the multiple reaction‐monitoring mode using the electrospray ionization technique. A simple liquid–liquid extraction process was used to extract NTP, OH‐NTP and IS from human plasma. The total run time was 2.5 min and the elution of NTP, OH‐NTP and IS occurred at 1.44, 1.28 and 1.39 min, respectively; this was achieved with a mobile phase consisting of 20 mm ammonium acetate : acetonitrile (20:80, v/v) at a flow rate of 0.50 mL/min on a HyPURITY C18 column. The developed method was validated in human plasma with a lower limit of quantitation of 1.09 ng/mL for both NTP and OH‐NTP. A linear response function was established for the range of concentrations 1.09–30.0 ng/mL (r > 0.998) for both NTP and OH‐NTP. The intra‐ and inter‐day precision values for NTP and OH‐NTP met the acceptance as per FDA guidelines. NTP and OH‐NTP were stable in a battery of stability studies, i.e. bench‐top, auto‐sampler and freeze–thaw cycles. The developed assay was applied to a pharmacokinetic study in humans. Copyright © 2010 John Wiley & Sons, Ltd.
Regeneration of total RNA purification silica‐based columns
Authors: Nicosia Aldo , Tagliavia Marcello , Costa Salvatore 
Published: April 2010

AbstractSilica‐based columns are largely used in RNA purification, allowing fast extractions and good yields of high quality nucleic acid, but their major limitation is the high cost. The reuse of such columns, although desirable, is not recommended because of residual amounts of material from the previous sample trapped in the column matrix, which might be released during further purification. Thus, recycling does need previous complete removal of any detectable RNA trace, but to date no protocol which allows decontamination and reuse is available. We report a very rapid decontamination procedure, based on treatment with warm alkaline solution containing Triton X‐100, which ensures no RNA carry‐over, and allows the recycling of columns without impairment of their efficiency in high‐quality RNA purification even after several regeneration rounds. Copyright © 2010 John Wiley & Sons, Ltd.
Liquid chromatography tandem mass spectrometry pharmacokinetic study of dl‐praeruptorin A in rat plasma
Authors: Ruan Hang , Zhang Zhen , Zhu Xuan 
Published: April 2010

Abstractdl‐Praeruptorin A is a novel drug with valuable apoptosis and inflammation inhibitory effects in cardiac muscle. Previous pharmacokinetic studies of dl‐praeruptorin A have had limited success due to its very low plasma concentrations. In this study, we developed and validated a new rapid, sensitive and specific high‐performance liquid chromatography electrospray ionization tandem mass spectrometry (HPLC/ESI–MS/MS) method for quantitative analysis of dl‐praeruptorin A in rat plasma. dl‐Praeruptorin A and diazepam (internal standard) extracted from rat plasma samples with chloroform and analyzed on an XTerra™ RP18 column (150 mm × 4.6 mm i.d., 5 µm) were chromatographically separated within 5.5 min using methanol–water (75:25, v/v; flow rate 1 mL/min) as the mobile phase. dl‐Praeruptorin A was detected in positive ion mode using multiple reaction monitoring. The method was validated and the specificity, linearity, lower limit of quantitation (LLOQ, 2.5 ng/mL), precision (intra‐ and inter‐day <11.0%), accuracy (90.2–96.3%), recovery (>79.2%) and stability were determined. The correlation coefficient (r2) for the linear range of 2.5–2500.0 ng/mL was >0.999. No matrix effects were observed. The validated method was successfully applied to pharmacokinetic studies of dl‐praeruptorin A after intravenous administration to rats. The LLOQ obtained with this method was lower than in previous studies and could be valuable for determination of dl‐praeruptorin A in therapeutic drug monitoring and preclinical studies to establish appropriate dose and frequency. Copyright © 2010 John Wiley & Sons, Ltd.
Essential‐Oil Composition, Antileishmanial, and Toxicity Study of Artemisia abyssinica and Satureja punctata ssp. punctata from Ethiopia
Authors: Tariku Yinebeb , Hymete Ariaya , Hailu Asrat , Rohloff Jens 
Published: April 2010

AbstractEssential oils of Artemisia abyssinica and Satureja punctata ssp. punctata from Ethiopia were analyzed by GC and GC/MS, and screened for leishmanicidal activity against promastigote and axenic amastigotes of Leishmania donovani and L. aethiopica, including toxicity studies on human monocytic leukemia cells (THP‐1) and erythrocytes in vitro. GC/MS of A. abyssinica oil revealed 67 compounds (99.94%) with the major constituents yomogi alcohol (38.47%), artemisyl acetate (24.88%), and artemisia alcohol (6.70%), and oxygenated monoterpenes (84.00%) as the dominant group. The oil of S. punctata contained 67 compounds (99.49%) with the main constituents geranial (27.62%), neral (21.72%), α‐bisabolol (13.62%), and (E)‐nerolidol (4.82%), of which oxygenated mono‐ and sesquiterpenes (58.39 and 26.91%, resp.) showed highest abundance. Both oils showed effect on promastigotes (MIC 76.5 to 312.5 nl/ml) and amastigotes (EC50 4.06 to 131.00 nl/ml) of L. donovani and L. aethiopica, and varying toxicities on THP‐1 cells (CC50 0.013 to 350 nl/ml with selectivity index between 0.001 and 28) and erythrocytes (with LC50 0.35 to 1.52 μl/ml). S. punctata oil exerted highest activity against both Leishmania sp. and toxicity. The revealed antileishmanial activities support further isolation and investigation of oil constituents for in vitro/in vivo evaluation.