bluuebunny/crossref_metadata_2025 huggingface dataset:
RELEASE OF POTASSIUM BY 18 ONTARIO SOILS DURING CONTINUOUS CROPPING IN THE GREENHOUSE
Authors: Smith J. A. , Matthews B. C.
Published: March 2010

Eighteen Ontario soils were ranked according to their capacity to supply potassium from non-exchangeable forms to eight successive crops of alfalfa. This capacity was found to be closely related to the percentage of clay in the soils. Potassium content of the alfalfa and total uptake of potassium were highly correlated with both exchangeable soil potassium and release of potassium from non-exchangeable forms. Exchangeable potassium levels below 100 lb. per acre gave low yields and potassium content of the crop. Excessively high exchangeable potassium levels resulted in luxury consumption of potassium by the crop or in fixation by the soil. In soils at or near their equilibrium exchangeable potassium levels, i.e., not heavily fertilized, there was a close relationship between potassium-supplying power and the exchangeable potassium content measured either before cropping commenced or at the end of the cropping period.
NOTE ON THE OCCURRENCE OF AMINO GROUPS IN SOIL ORGANIC MATTER
Authors: SOWDEN F. J.
Published: March 2010

not available
THE FORMS OF NITROGEN IN THE ORGANIC MATTER OF DIFFERENT HORIZONS OF SOIL PROFILES
Authors: Sowden F. J.
Published: March 2010

A study was made of the amount of amide-N (as glutamine and asparagine) in soil materials by methylating the organic material with methanolic-HCl, reducing the resulting product with LiBH4and determining the loss of glutamic and aspartic acids. The data obtained lend support to the hypothesis that a percentage of the ammonia-N formed on acid hydrolysis, equal or nearly equal to the sum of the glutamic acid-N + the aspartic acid-N, is derived from glutamine and asparagine. An attempt to use other methods to determine the amount of amide-N in soil materials indicated that these methods would not, in general, be reliable, although they might give acceptable results when the degree of decomposition of the organic materials was not too great (e.g., in the A00or A0horizons).
MEASUREMENT OF NITRATE-SUPPLYING POWER OF SOILS BY AN INCUBATION METHOD AND CORRELATION WITH CROP YIELD RESPONSE
Authors: Eagle D. J. , Matthews B. C.
Published: March 2010

The results of an incubation method for measuring the capacity of Ontario soils to accumulate nitrate were extremely variable. Placement of the soil sample between two layers of vermiculite in the incubation tube and addition of sufficient distilled water to moisten the top layer of vermiculite, the soil and a portion of the bottom layer of vermiculite resulted in satisfactory reproducibility of results. Wide fluctuations in results, due to prolonged air-dry storage before analysis or to time of sampling during the growing season, were reduced by storing all samples in the moist state at 10 °C. for 2 weeks before analysis.The correlation between the logarithm of the percentage yield decrement, which is a measure of crop response, and nitrate-supplying power as measured by the modified incubation method was highly significant for winter wheat (r = −0.437), oats (r = −0.411) and potatoes (r = −0.651). Soils having a nitrate-supplying power of 50 p.p.m. of N or more by the proposed modified method gave little or no increase in yield of wheat, oats, or potatoes when additional nitrogen was applied as fertilizer.
THE PELTIER EFFECT AND ITS USE FOR DETERMINING RELATIVE ACTIVITY OF SOIL WATER
Authors: Korven H. C. , Taylor S. A.
Published: March 2010

An apparatus is described which involves the use of a small thermocouple, cooled to the dew point by the Peltier effect, as a means of determining the relative activity of water in soils.Thermocouples were calibrated over a series of sulphuric acid solutions immersed in a constant temperature bath controlled to within 0.003 °C. The temperature of the bath for all readings was 25 °C. Readings were taken over Benjamin silty clay loam soil samples that had been brought to desired soil moisture relative activities by the pressure plate and pressure membrane methods. The following conclusions were reached:1. The thermocouple technique shows promise as a laboratory procedure for determining the relative activity of water in soils.2. The majority of the results showed a gradual lowering of the readings with time. This was overcome at the expense of speed by treating the thermocouple with a plastic spray paint.3. More study and testing are required before the technique can be considered a completely satisfactory procedure.
EFFECT OF FROST ACTION ON STRUCTURE OF HALDIMAND CLAY
Authors: Logsdail D. E. , Webber L. R.
Published: March 2010

A laboratory study was carried out to determine the breakdown of soil structure by alternate freezing and thawing. Surface samples of Haldimand clay from plots cropped with corn for the 3 previous years and from plots of continuous blue grass sod were used.Cycles of freezing and thawing caused a significant breakdown of aggregates from the sod plots at all moisture levels employed except the one equivalent to 1.0 atmosphere pressure. The destructive effects of alternate freezing and thawing increased with increasing moisture in the well-aggregated soil (blue grass), but the effects on a poorly aggregated soil (corn) were not significant.
ASSESSING NITROGEN REQUIREMENTS OF SOME ALBERTA SOILS
Authors: Synghal K. N. , Toogood J. A. , Bentley C. F.
Published: March 2010

Fifty Alberta soils, representing the six soil zones of the Province, were sampled for greenhouse and laboratory tests. Five successive crops of oats were produced in greenhouse tests involving a number of different nitrogen applications. In the laboratory the soils were subjected to a number of different nitrogen tests, including three methods of incubation for nitrate accumulation. Analytical data were then correlated with greenhouse yields. Also available for correlation were some data on fertilizer responses in the field.Nitrate nitrogen accumulating in unleached soils after a 2-week Incubation period at 28 °C. showed the best positive correlation with crop yield and the lowest negative correlation with crop response to added nitrogen. Correlation was good, however, only when growing conditions were carefully controlled. Using leached soils for the incubation test or using a 4-week incubating period resulted in lower values. Total nitrogen, 'available' nitrogen, and N values appeared to be of little value in assessing nitrogen requirements: of the soils tested.
THE EFFECT OF FERTILIZERS AND OSMOTIC PRESSURE ON GERMINATION
Authors: Dubetz S. , Smith R. L. , Russell G. C.
Published: March 2010

Results of germination studies with canning corn, field beans, and sugar beets at three soil moisture levels and under five fertilizer treatments, along with the results of germination of sugar beets at iso-osmotic concentrations of mannitol and ammonium nitrate solutions, are reported.The moisture levels alone had no significant effect on the germination of any of the crops. Moisture levels in combination with nitrogen fertilizers reduced germination, and the reduction became progressively pronounced with decreasing moisture. Nitrogen caused a greater reduction than mannitol or P2O5. With only one-quarter of the available moisture in the soil, the nitrogen treatments resulted in virtually no germination of any of the three crops. There were significant differences in response pattern among species, with canning corn being the least sensitive and field beans showing the greatest reduction due to fertilizer damage. Results indicate that no fertilizer should be placed in contact with bean seeds. The highly soluble fertilizer, ammonium nitrate, should not be placed in contact with corn or beet seeds when soil moisture is limiting.Germination of sugar beets was significantly lowered in solutions having osmotic pressures exceeding 4 atmospheres. With increasing osmotic pressure at iso-osmotic concentrations, germination of sugar beets was lower in ammonium nitrate solutions than in mannitol solutions, suggesting toxicity of the nitrate or ammonium ions.
NOTE ON THE AGGREGATE-SIZE DISTRIBUTION AND AGGREGATE STABILITY IN HALDIMAND CLAY TREATED WITH FOUR SOIL ADDITIVES
Authors: WEBBER L. R.
Published: March 2010

not available
PHOSPHORUS FRACTIONS IN A SOIL SAMPLED AT DIFFERENT DEPTHS AND THE EFFECT OF LIME AND FERTILIZER ON OATS AND CLOVER IN A GREENHOUSE TEST
Authors: Hamilton H. A. , Lessard J. R.
Published: March 2010

Soil samples were collected at four different depths from a virgin soil, and in a region where deep ploughing has been a common practice. Chemical analyses revealed that the sub-surface samples were more highly saturated with bases than were the surface samples. In the 0–6 inch layer the percentage contribution of calcium, aluminium and iron phosphate to total soil phosphorus was 41.1, 10.4 and 2.8 respectively; while, in the 18–24 inch layer the percentages were 88.4, 2.8 and 0.5 respectively. Organic phosphorus decreased with depth.In the greenhouse there were highly significant differences between oat yields on the various layers, the surface soil giving the highest yields. Clover crop yields tended to be better as depth of profile increased. Phosphorus increased oat yields and clover yields on all soil layers. As a result of over-liming in certain instances clover yields were depressed in the absence of applied phosphate fertilizer, whereas oat yields were unaffected.
A LONG-TERM FIELD EXPERIMENT WITH COMMERCIAL FERTILIZERS AND MANURE: I. Fertility levels and crop yields in a rotation of swedes, oats and hay
Authors: MacLeod L. B. , Bishop R. F. , Jackson L. P. , MacEachern C. R. , Goring E. T.
Published: March 2010

In a field experiment, conducted from 1936 to 1957, a rotation of swedes, oats and hay was followed and treatments included commercial fertilizers and manure.Changes in the chemical composition of the soil during the experiment included significant decreases in soil organic matter, total nitrogen and cation exchange capacity. In no case was the initial content of exchangeable potassium maintained and although changes in adsorbed and easily acid-soluble phosphorus were negligible with a number of treatments only one resulted in a significant increase.The treatments were applied in the swede year and yield differences with this crop were greater than for either the oats or hay. Data for the latter two crops indicated that with most of the treatments there was a tendency for yields to decline as the experiment progressed. This was not the case with swedes where variation in yields with rotation cycles was greater than it was in the case of oats or hay. There was a considerable residual effect from manure, and phosphorus had a greater effect on yields than either nitrogen or potassium.
THE INFLUENCE OF SOIL TEMPERATURE ON THE GROWTH AND MINERAL COMPOSITION OF OATS
Authors: Nielsen K. F. , Halstead R. L. , MacLean A. J. , Holmes R. M. , Bourget S. J.
Published: March 2010

Oats grown with different nutrient treatments in temperature-controlled soil in the greenhouse produced higher yields of grain and straw when soil temperature was increased from 41° to 67°F. Yields were usually less at 80°F. than at 41°F. This relationship between growth and soil temperature was also apparent at the heading stage. At 7th leaf, however, the best temperature for growth varied with nutrient treatment. Root yields usually decreased with increase in soil temperature.Increasing soil temperature from 41° to 67°F. increased uptake of N, P and K. In many instances increases in the concentration of N, P and K in the plant contributed to these increases in uptake. The effect of soil temperature on uptake was more consistent for P than for other elements.Nitrates and native phosphorus in incubated soil samples increased with increase in temperature from 41° to 80°F. but exchangeable K values were not affected.
Chikungunya Virus in North-Eastern Italy: A Seroprevalence Survey
Authors: Moro Maria Luisa , Gagliotti Carlo , Silvi Giuliano , Angelini Raffaella , Sambri Vittorio , Rezza Giovanni , Massimiliani Erika , Mattivi Andrea , Grilli Elisa , Finarelli Alba Carola , Spataro Nadir , Pierro Anna Maria , Seyler Thomas , Macini Pierluigi
Published: March 2010

After an outbreak of Chikungunya infection in Emilia-Romagna Region (North-eastern Italy), a survey was performed to estimate the seroprevalence of antibody to Chikungunya virus and the proportion of asymptomatic infections, to identify factors associated with infection, and evaluate the performance of the surveillance system. The method used was a survey on a random sample of residents of the village with the largest number of reported cases. The prevalence was 10.2% (33 of 325), being higher in older people and males, and lower when window screens and insect repellents were used. Only 18% of infected persons were fully asymptomatic, 85% of the 27 symptomatic confirmed cases satisfied the surveillance case definition, and 63% of the persons meeting the criteria for suspect case were identified by the active surveillance system. This study provides basic parameters for modeling the transmission potential of outbreaks and planning control measures for Chikungunya infection in temperate settings.
Multigeneration Method to Evaluate Effects of Pollutants on the Reproduction of Freshwater Snails
Authors: Oliveira-Filho Eduardo C. , Geraldino B. R. , Grisolia C. K. , Paumgartten F. J. R.
Published: March 2010

Ecotoxicity tests have been useful to guide regulatory decisions for pollution control to prevent adverse effects on aquatic ecosystems. Routine assays are based on acute or sub-chronic exposures and may be inadequate for detecting a reproductive impairment after long-term exposure to low concentrations of pollutants. To help adress this gap was proposed a mutigeneration method to evaluate the effects of chemicals on the reproduction of Biomphalaria tenagophila snail. Chemicals tested include two environmental pollutants, the pesticide endosulfan and the industrial chemical nonylphenol ethoxylate. Adult snails (10 per concentration) were individually exposed to non acutely lethal concentrations for two generations. Endpoints evaluated include: survival, fecundity and embrionic development. Results showed that some adverse effects on reproduction were observed only after continuous exposure lasting longer than one generation. A comparative analysis with results of classic short-term chronic tests show that the multigeneration study designed seems to be a sensitive approach to evaluate chronic effects of environmental pollutants.
Avoidance Test Using Earthworms (Eisenia fetida) for Contaminated Sites Evaluation: Preliminary Results for Hydrocarbon Contamination
Authors: Sisinno Cristina L. S. , Bulus M. R. M. , Rizzo A. C. , Moreira J. C.
Published: March 2010

Problems related to contaminated sites are increasing in Brazil. These sites can be represented by gas station, waste disposal areas, abandoned industrial facilities, etc. and in general are located in the neighborhood of important ecosystems, being cause of negative impacts. Evaluation of contaminated sites in Brazil has been done using only chemical parameters, without ecotoxicological studies. The aim of this study was initiate preliminary tests according to the draft of ISO that describes an avoidance test used to assess soil quality and toxicity from chemical to Eisenia fetida (earthworm). This test can be applied as a rapid screening test to determinate the bioavailability of chemicals or contaminants in soil to E. fetida, where the avoidance behaviour is used as indicator. In accordance to the results, it can be decided if reproduction test with the same species must be performed. Samples from contaminated sites with different hydrocarbons concentrations collected from a bus garage, a gas station and a contaminated oil spilling area were analysed. The results of the sample from the bus station showed that 96% of the organisms escaped from the contaminated sample section to the control soil section. This indicates that the sample can be considered toxic, presenting the habitat function limited. The toxicity of this sample was confirmed later by mortality and reproduction tests. The preliminary results indicated that avoidance test was a rapid indicator of sample toxicity and can be applied as a complement to evaluate hydrocarbons contaminated sites.
Comparative Study of Sediment Quality From the Tietê River Reservoirs (SP)
Authors: Almeida Caio Augusto de , Rocha O.
Published: March 2010

There is a general consensus that the sediment from water bodies plays a fundamental role in the transport dynamics, accumulation and availability of pollutants. In the sediments quality triad, considered one of the best approaches for the study of anthropogenic contaminated aquatic systems, the chemical and biological data (bioassays and benthic community analysis) are combined to show the degradation of each site. The RTM (ratio to maximum value) values provide useful visual information, because they can be plotted in axes with common origin. Therefore, a relative measure of sediment degradation can be obtained, by calculating the area formed by the figure obtained for each station or site. This comparative design of study was applied as an alternative to the multivariate analyses (PCA, Cluster, etc.) to the data obtained by the Qualised project – Technical-Scientific Bases For the Development of Sediment Quality Criteria – for the 2000 to 2001 period. The results allow the classification of the reservoirs based on their respective sediment quality and indicate the degradation vectors they are subject to. The spatial distribution of sediments potentially toxic accompanies the trophic gradient of Tietê River, i.e., the downstream reservoirs are less eutrophicated than the upstream ones. Therefore, the quality of the sediments improves with the distance from the metropolitan area of São Paulo confirming the origin of most of pollutant substances. The sediments of Rasgão and Billings reservoirs were considered those with lower quality, while those from Promissão reservoir present a better condition.
Toxicity Evaluation of Surface Water Samples Preserved in Different Ways: Refrigeration and Freezing
Authors: Aragão Márcia Aparecida , Bertoletti Eduardo
Published: March 2010

The correct proceedings for sample collection, preservation and storage regarding toxicity tests with aquatic organisms, will guarantee the reliability of results of these tests. Recently, some standard procedures advise that samples should be preserved by refrigeration (for a short time) or by freezing (for a long time). The aim of this study was to compare the results of chronic toxicity tests with Ceriodaphnia dubia using, to the renewal of test solutions, samples with two different ways of preservation: refrigeration (temperature at 2 to 5°C) and freezing in aliquots (temperature at –3 to –25°C). Tests results indicated that there was no significant differences on toxicity to C. dubia, between samples refrigerated or frozen.
Toxicity and Genotoxicity of Copper Sulphate in Freshwater Planarians and Mice
Authors: Prá D. , Guecheva T. , Franke S. I. R. , Knakievicz T. , Erdtmann B. , Henriques João Antonio Pêgas
Published: March 2010

Environmental contamination with copper-containing compounds is significant. Copper sulfate is largely applied in industrial and agricultural processes. To compare the toxicity of compounds between species is fundamental for predicting environmental hazards. The goal of this paper is to compare the toxicity and genotoxicity of copper sulfate between planarians, an early eukaryote, and mice, a mammal with striking similarities with humans. In planarians, copper sulfate induced DNA damages in a dose-related fashion (r = 0.984; p < 0.001) and the higher doses of the compound induced more damage than the controls when evaluated by the comet assay. Doses ten fold lower than the used in acute tests induced significant genotoxicity in cronic tests. Repair studies showed a low repair capability for the acute doses after 24 h. The post-treatment with CuSO4 reduced the repair of the DNA damages generated by the DNA alkylating agent methyl methanesulfonate (MMS). The copper sulfate also induced significant concentration-related influence in planarian regeneration (r = 0.822 and p < 0.001). In mice, a dose of 20.72 mg CuSO4 per kg of body weight induced a significant increase in DNA damage 24 h after the exposure; and the repair was effective after 48 h from the exposure, when evaluated by the comet assay. Results indicate toxicity and genotoxicity as well as repair interference potential for copper sulfate, supporting a possible interference of the metal in the toxicity of environmental pollutants.
Studying the Use and Risks of Contamination by Pesticides in a Land Reform Settlement in the North Fluminense Region, Brazil
Authors: Pedlowski Marcos A. , Aquino S. L. de , Canela M. C. , Silva I. L. A. da
Published: March 2010

During the twentieth century, the agricultural economy benefited tremendously from new developments in chemical pesticides. This progress, however, has resulted in unintended consequences to human health and the environment. This article presents the results of a study carried out on land reform settlement located on the North Fluminense region. Data was obtained by surveying one hundred land reform settlers through a random sample questionnaire. Variables studied include household demography and education, types of pesticides, targeted crops, levels of training for pesticides handling, disposal of empty containers and use of safety equipments. Our results show that about half of the households were using pesticides to eradicate weeds and different types of agricultural pests on eleven crops. Data also showed a dominance of products with moderate toxicity for human health and high toxicity for the environment. The risk for increased contamination associated to pesticides utilization was greatly enhanced by a general lack of understanding regarding health and environmental risks. Most settlers declared having previously received no formal training for the handling and disposing of products being used in their lots. We  also found that most settlers were littering their lots with empty containers and had unrestricted access to pesticides retailers.  Finally, our results show the need for the education on the health and environmental risks involved in misguided utilization of  pesticides, and for the mapping of aquatic systems environmental contamination associated to pesticides utilization.
Effect of Malathion and Maca (Lepidium meyenii) on Espermatogenis of Mice
Authors: Bustos-Obregón Eduardo , Diederichs T. , Del Rio F. Costa , Sarabia L.
Published: March 2010

Malathion induces testicular alterations related to decrease of fertility in different species. The extract of a plant (Maca) was utilized to analyze if it has an antagonistic effect to malathion. For this trial, for which 52 mice of 12 weeks of age were utilized, distributed in 4 groups (Control, Maca, Malathion, Maca + Malathion) and injected intraperitoneally with Malathion or NaCl 0.9% and/or Maca (given orally by means of an esophagic tube) mice were sacrificed at days 1, 7, 14 and 21. The frequency of the stages of the seminiferous epithelium was determined in histological sections staind with Peryodic Acid Schiff – Hematoxylin for the evaluation of the spermatic acrosomas. The data were analyzed with the t non parametric test of ANOVA of Kruskal-Wallis, and multivariable analysis of Dunn. At day 1 post treatment it was observed that the stage XII is more frequent with Maca and Malathion + Maca but diminishes with Malathion by day 7. A significative increase of the stage VII is found in the group treated with Malathion. At day 14 an increase of the stage VIII is seen in the group treated with Malathion, which is not the case for group treated with Malathion + Maca, the same situations is found by day 21 in the stage IX. These results suggest that Malathion alters the frequency of stages of the cycle while Maca protects the tubules from this damage.
Mussel Reference Material Preparation Proposal as a Quality Assurance Tool for Brazilian Seashore Biomonitoring
Authors: Moreira Edson Gonçalves , Vasconcellos M. B. A. , Maihara V. A. , Catharino M. G. M. , Saiki M.
Published: March 2010

Analytical measurement results may affect economical, political and environmental protection decisions. Therefore, there is a growing demand for quality assurance of such results. The use of certified reference materials, CRMs, is a simple and efficient way to validate analytical methods and to keep them under control. However, CRMs are expensive and usually obtained abroad, which makes their use prohibitive for a large number of Brazilian chemical laboratories. This paper presents a proposal for the preparation of a mussel reference material using the Perna perna species. This material will be used in biomonitoring studies of the Brazilian Seashore. The various aspects of the preparation such as sampling, processing, physical and chemical characterization are presented. Preliminary results for the concentration of elements such as As, Br, Co, Cr, Fe, K, Na, Se and Zn determined by INAA and Cd and Hg determined by AAS, are also presented.
Toxicological Effect of Aqueous Samplings of Junin Lake, Peru, on Chironomus calligraphus
Authors: Iannacone José , Salazar N.
Published: March 2010

Chironomus calligraphus (Goeldi 1905) (Diptera: Chironomidae) is a characteristic species of natural environment and of treated domestic waste water of Peru. Acute toxic effects of aqueous samples from three regions of the second lake of higher area in Peru, Junin Lake, between July 2000 to January 2001 on larvae of C. calligraphus at 48 h exposure were evaluated. The lethal concentration medium (LC50) employing C. calligraphus at Junin Lake showed the following order of toxicity: Upamayo Reservoir (LC50 = 14.79%) > Upamayo Bridge (LC50 = 24.72%) > Pari (LC50 = 41.81%). The highest toxic value of LC50 was observed on December 2000 and the lowest toxic value in January 2001. Fe3+, Pb2+ and Cd2+ were found over the maximum permissible levels of water quality Class VI (zone of preservation of aquatic wildlife) according to Peruvian legislation. C. calligraphus showed to be a suitable species for ecotoxicological assays aimed to analyze water samples.
Supercritical Phase Catalysis—Heterogeneous
Authors: Subramaniam Bala , Ford Jackson W.
Published: March 2010

The potential applications of supercritical reaction media in heterogeneous catalysis have greatly expanded in recent years to include industrially significant reactions such as selective catalytic oxidations (fine and agricultural chemicals), fixed‐bed hydrogenations (pharmaceuticals, chemical intermediates), polymerizations, hydroformylations (petrochemical), and solid‐acid catalyzed alkylations (petroleum refining). The near‐critical region (roughly 1.05‐1.2 Tc; and 0.9 ‐ 2.0 Pc) provides access to unique fluid properties (liquid‐like densities and gas‐like transport properties) that have been exploited in heterogeneous catalytic systems in numerous ways such as these: eliminating oxygen or hydrogen solubility limitations in the liquid phase of multiphase reaction systems; enhanced desorption and transport of heavy molecules (such as coke precursors) in mesoporous catalysts alleviating pore‐diffusion limitations and improving catalyst effectiveness; in situ removal of primary reaction products maximizing their selectivity; enhanced heat capacity ameliorating the problem of parametric sensitivity in exothermic fixed‐bed reactors; and facile separation of reactants and products. Supercritical reaction systems are thus excellent examples of the ‘multifunctional reactor’ concept. This chapter provides an overview of recent advances in each of these areas including fundamental and experimental aspects. Barriers and challenges confronting application of CO2‐based processes in industrial catalysis, and advances in overcoming these barriers are highlighted.
Transport Effects ‐ Homogeneous
Authors: Garland Marc
Published: March 2010

In the present contribution, the effects of different types of mass‐transfer on homogeneous catalytic reactions are addressed. In particular, emphasis is given to the effects of mass‐transfer on the precatalytic reactions as well as the turnover frequency. Various types of transport effects are considered. These include gas–liquid and liquid–liquid mass transfer, segregation and mixing of solutions, as well as dissolution kinetics of sparingly soluble organometallics and cage effects. A number of criteria are suggested for comparing the rates of mass transfer with various rates of reaction. A checklist is proposed for the experimentalist to assist in identifying potential mass‐transfer control issues. Simple steps to mitigate these complications are suggested.
How Catalysts Affect the Growth of Single‐Walled Carbon Nanotubes on Substrates
Authors: Li Yan , Cui Rongli , Ding Lei , Liu Yu , Zhou Weiwei , Zhang Yan , Jin Zhong , Peng Fei , Liu Jie
Published: March 2010

Direct growth of single‐walled carbon nanotubes (SWNTs) on flat substrates by chemical vapor deposition (CVD) is very important for the application of SWNTs in nanodevices. In the growth process, catalysts play an important role in controlling the structure of SWNTs. Over the years, we have systematically studied the size‐controlled synthesis of Fe‐based nanoparticles and the CVD growth of SWNTs, especially the horizontally aligned SWNTs, catalyzed by these produced nanoparticles. Some new catalysts were also developed. Among them, Cu is shown to be a superior catalyst for growing SWNT arrays on both silicon and quartz substrates and Pb is a unique catalyst from which one can obtain SWNTs without any metallic contaminant. SWNTs prepared with both Cu and Pb are very suitable for building high‐performance nanodevices. These studies are also very helpful for further understanding the growth mechanism of SWNTs.
Facile Creation of 3‐Indolyl‐3‐hydroxy‐2‐oxindoles by an Organocatalytic Enantioselective Friedel–Crafts Reaction of Indoles with Isatins
Authors: Deng Jing , Zhang Shilei , Ding Peng , Jiang Hualiang , Wang Wei , Li Jian
Published: March 2010

The first direct enantioselective Friedel–Crafts reaction of indoles with isatins has been developed. The process is catalyzed by simple cupreine under mild reaction conditions and affords synthetically and biologically interesting, chiral 3‐indolyl‐3‐hydroxy‐2‐oxindoles in good yields (68–97%) and with high enantioselectivities (76–91%).
Mycophagy and its influence on habitat use and ranging patterns in Callimico goeldii
Authors: Porter Leila M. , Garber Paul A.
Published: March 2010

Mycophagy has been documented in a number of species of marmosets and lion tamarins (Callitrichinae) but its effect on ranging behavior is not known. We present the results of 10 years of research on five groups of Goeldi's monkey (Callimico goeldii) at a field site in northwestern Bolivia. We studied the diet and ranging behavior of two of the groups. On average, groups contained 4.5 individuals (range 2.0–9.0), but they gradually decreased in size until only the breeding female remained in the home range. The annual diet was composed of fungi (31.1–34.9%), fruits (34.0–40.6%), prey (17.4–30.1%), and exudates (1.0–10.9%). They had large home ranges (114–150 ha) and over time individuals tended to shift their core areas of use. They used secondary and bamboo forest and forest with dense understories more than expected based on availability. We suggest that the large home ranges and shifting core areas used by C. goeldii are components of a foraging strategy to track patchy, low density, and ephemeral fungal fruiting bodies. Our results, along with data published on other callitrichines, indicate that groups of Leontopithecus, Callithrix, and Callimico that eat fungi have larger home ranges than those that do not. Mycophagy is one of the several factors that evidently affect home range size in callitrichines. Fungi are clearly an important food source for a number of populations, but additional studies are needed to determine why some eat fungi frequently while others do not. Am J Phys Anthropol, 2010. © 2010 Wiley‐Liss, Inc.
Asymmetrische Organokatalyse mit Sulfonen
Authors: Nielsen Martin , Jacobsen Christian Borch , Holub Nicole , Paixão Marcio Weber , Jørgensen Karl Anker
Published: March 2010

Die asymmetrische Organokatalyse hat sich zu einer effektiven Methode für die Herstellung optisch aktiver Verbindungen entwickelt. Während sich erste Untersuchungen im Wesentlichen auf die Verwendung einfacher Reagentien als Nachweis der Realisierbarkeit konzentrierten, befassen sich neuere Studien der asymmetrischen Organokatalyse nun damit, das Konzept auf ziel‐ und diversitätsorientierte Synthesen zu erweitern. Dank ihrer zahlreichen Transformationsmöglichkeiten und ihrer Fähigkeit zur Generierung nucleophiler wie auch elektrophiler Reaktionspartner spielen dabei Sulfone als Substrate eine besondere Rolle in der Organokatalyse.
To Protonate or Alkylate? Stereoselective Brønsted Acid Catalysis of CC Bond Formation Using Diazoalkanes
Authors: Johnston Jeffrey N. , Muchalski Hubert , Troyer Timothy L.
Published: March 2010

A new means to activate diazoalkanes has been discovered and applied broadly over the past few years. Brønsted acids, both achiral and chiral, have been used to promote the formation of carbon–carbon and carbon–heteroatom bonds with a growing number of diazoalkane derivatives. Aside from their straightforward ability to build structural and stereochemical complexity in innovative new ways, these transformations are remarkable owing to their ability to skirt competitive diazo protonation—a reaction that has long been used to prepare esters efficiently and cleanly from carboxylic acids. In cases where achiral Brønsted acids are used, high diastereoselection can be achieved. Meanwhile, chiral Brønsted acids can deliver products with both high diastereo‐ and enantioselectivity. More recently, systems have emerged that combine Brønsted acids and either Lewis acids or transition metals to promote carbon–carbon bond formation from diazoalkanes.
Asymmetric Organocatalysis with Sulfones
Authors: Nielsen Martin , Jacobsen Christian Borch , Holub Nicole , Paixão Marcio Weber , Jørgensen Karl Anker
Published: March 2010

Asymmetric organocatalysis has become a powerful tool for the synthesis of optically active compounds. Whereas early research mainly focused on combining simple reagents as a proof‐of‐concept for asymmetric organocatalysis, recent investigations are directed towards extending the concept to more target‐ and diversity‐oriented synthesis. As a result of the many transformation possibilities and their ability to generate both nucleophilic and electrophilic reaction partners, sulfones have become especially important substrates in the field of organocatalysis.
Synthesis, characterization and single crystal structure determination of aluminum alkoxydisilanolates: precursors for silica–alumina composite
Authors: Amini Mostafa M. , Mohammadnezhad Gholamhossein , Mirzaee Mehdi , Khavasi Hamid Reza
Published: March 2010

Several novel aluminum alkoxydisilanolate complexes were prepared by reaction of triphenylsilanol with aluminum 2‐methoxyethoxide, aluminum 2‐ethoxyethoxide, aluminum sec‐butoxide and aluminum iso‐propoxide. All new complexes, [(Ph3SiO)2Al(OR)]2 [where R = CH2CH2OCH3 (1), CH2CH2OC2H5 (2), CH(CH3)CH2CH3 (3) and CH(CH3)2 (4)] were characterized by elemental analysis, mass spectrometry and infrared spectroscopy (IR), as well as 1H, 13C, 29Si and 27Al NMR spectroscopies. The solid‐state structures of the representative compound 2 and 4 were also verified by single‐crystal X‐ray analyses. Complexes 2 and 4 are dimers having distorted trigonal bipyramidal and tetrahedral coordination at the aluminum center, respectively. The 27Al NMR spectrum of compound 2 showed that the solid‐state structure of the complex was not retained in solution, and tetracoordinated aluminum was found in solution in contrast to the pentacoordinated geometry in the solid state. The hydrothermal treatment of 1 and 4 at 200 °C and the subsequent calcination at 1000 °C resulted in the formation of alumina–silica composite (4SiO2·Al2O3) with γ‐alumina in the silica matrix. Copyright © 2010 John Wiley & Sons, Ltd.
Discovery and Syntheses of “Superbug Challengers”—Platensimycin and Platencin
Authors: Palanichamy Kalanidhi , Kaliappan Krishna P.
Published: March 2010

Bacteria have developed resistance to almost all existing antibiotics known today and this has been a major issue over the last few decades. The search for a new class of antibiotics with a new mode of action to fight these multiply‐drug‐resistant strains, or “superbugs”, allowed a team of scientists at Merck to discover two novel antibiotics, platensimycin and platencin using advanced screening strategies, as inhibitors of bacterial fatty acid biosynthesis, which is essential for the survival of bacteria. Though both these antibiotics are structurally related, they work by slightly different mechanisms and target different enzymes conserved in the bacterial fatty acid biosynthesis. This Focus Review summarizes the synthetic and biological aspects of these natural products and their analogues and congeners.
Modified [(IPr)Pd(R‐acac)Cl] Complexes: Influence of the acac Substitution on the Catalytic Activity in Aryl Amination
Authors: Marion Nicolas , Navarro Oscar , Stevens Edwin D. , Ecarnot Elise C. , Bell Andrew , Amoroso Dino , Nolan Steven P.
Published: March 2010

The synthesis of a series of [(IPr)Pd(R‐acac)Cl] precatalysts (acac=acetylacetonato; IPr=1,3‐bis(2,6‐diisopropylphenyl)imidazol‐2‐ylidene), where the acac ligand on palladium has been systematically modified through terminal substitution, is reported. The following substituted acac ligands are employed in this study: dibenzoylmethanato (dbm), benzoylacetonato (bac), tetramethylheptanedionato (tmhd), and hexafluoroacetylacetonato (hfac). Full spectroscopic characterization of the new complexes is provided along with X‐ray studies for three of these. Investigation of their catalytic activity in cross‐coupling is also presented through a comparative study in an aryl amination reaction. The catalytic results show a strong correlation between the increased steric bulk of the acac substituents and an increased activation rate of the precatalyst, going from the acac to the tmhd ligand. This observation, along with the inertness of the hfac compound, seems to support our previous proposal for the activation mechanism of these complexes under cross‐coupling conditions.
Rational Design of Pseudozyma antarctica Lipase B Yielding a General Esterification Catalyst
Authors: Liu Danni , Trodler Peter , Eiben Sabine , Koschorreck Katja , Müller Monika , Pleiss Jürgen , Maurer Steffen C. , Branneby Cecilia , Schmid Rolf D. , Hauer Bernhard
Published: March 2010

Pseudozyma antarctica lipase B (CALB) shows activity in the acrylation of hydroxypropylcarbamate, a racemic mixture of enantiomers of primary and secondary alcohols. However, full conversion is hampered by the slowly reacting S enantiomer of the secondary alcohol. The same is true for a wide range of secondary alcohols, for example, octan‐2‐ and ‐3‐ol. In order to get high conversion in these reactions in a short time, the stereospecificity pocket of CALB was redesigned by using predictions from molecular modeling. Positions 278, 104, and 47 were targeted, and a library for two‐site saturation mutagenesis at positions 104 and 278 was constructed. The library was then screened for hydrolysis of acrylated hydroxypropylcarbamates. The best mutants L278A, L278V, L278A/W104F, and L278A/W104F/S47A showed an increased conversion in hydrolysis and transesterification of more than 30 %. While the wild‐type showed only 73 % conversion in the acrylation of hydroxypropylcarbamate after 6 h, 97 % conversion was achieved by L278A in this time. Besides this, L278A/W104F reached >96 % conversion in the acrylation of octan‐2‐ and ‐3‐ol within 48 h and showed a significant decrease in stereoselectivity, while the wild‐type reached only 68 and 59 % conversion, respectively. Thus the new biocatalysts can be used for efficient transformation of racemic alcohols and esters with high activity when the high stereoselectivity of the wild‐type hampers complete conversion of racemic substrates in a short time.
Gramicidin S Derivatives Containing cis‐ and trans‐Morpholine Amino Acids (MAAs) as Turn Mimetics
Authors: Kapoerchan Varsha V. , Spalburg Emile , de Neeling Albert. J. , Mars‐Groenendijk Roos H. , Noort Daan , Otero José M. , Ferraces‐Casais Patricia , Llamas‐Saiz Antonio L. , van Raaij Mark J. , van Doorn Joop , van der Marel Gijs A. , Overkleeft Herman S. , Overhand Mark
Published: March 2010

The cyclic decapeptide gramicidin S (GS) was used as a model for the evaluation of four turn mimetics. For this purpose, one of the D‐Phe‐Pro two‐residue turn motifs in the rigid cyclic β‐hairpin structure of GS was replaced with morpholine amino acids (MAA 2–5), differing in stereochemistry and length of the side‐chain. The conformational properties of the thus obtained GS analogues (6–9) was assessed by using NMR spectroscopy and X‐ray crystallography, and correlated with their biological properties (antimicrobial and hemolytic activity). We show that compound 8, containing the dipeptide isostere trans‐MAA 4, has an apparent high structural resemblance with GS and that its antibacterial activity against a panel of Gram positive and ‐negative bacterial strains is better than the derivatives 6, 7 and 9.
Direct Synthesis of Titanium Complexes with Chelating cis‐9,10‐Dihydrophenanthrenediamide Ligands through Sequential CC Bond‐Forming Reactions from o‐Metalated Arylimines
Authors: Zhao Dapeng , Gao Wei , Mu Ying , Ye Ling
Published: March 2010

A series of new titanium(IV) complexes with o‐metalated arylimine and/or cis‐9,10‐dihydrophenanthrenediamide ligands, [o‐C6H4(CHNR)TiCl3] (R=2,6‐iPr2C6H3 (3 a), 2,6‐Me2C6H3 (3 b), tBu (3 c)), [cis‐9,10‐PhenH2(NR)2TiCl2] (PhenH2=9,10‐dihydrophenanthrene; R=2,6‐iPr2C6H3 (4 a), 2,6‐Me2C6H3 (4 b), tBu (4 c)), [{cis‐9,10‐PhenH2(NR)2}{o‐C6H4(HCNR)}TiCl] (R=2,6‐iPr2C6H3 (5 a), 2,6‐Me2C6H3 (5 b), tBu (5 c)), have been synthesised from the reactions of TiCl4 with o‐C6H4(CHNR)Li (R=2,6‐iPr2C6H3, 2,6‐Me2C6H3, tBu). Complexes 4 and 5 were formed unexpectedly from the reactions of TiCl4 with two or three equivalents of the corresponding o‐C6H4(CHNR)Li followed by sequential intramolecular CC bond‐forming reductive elimination and oxidative coupling reactions. Attempts to isolate the intermediates, [{o‐C6H4(CHNR)}2TiCl2] (2), were unsuccessful. All complexes were characterised by 1H and 13C NMR spectroscopy, and the molecular structures of 3 a, 4 a–c, 5 a, and 5 c were determined by X‐ray crystallography.
Enantioselective Organocatalytic Addition of Oxazolones to 1,1‐Bis(phenylsulfonyl)ethylene: A Convenient Asymmetric Synthesis of Quaternary α‐Amino Acids
Authors: Alba Andrea‐Nekane R. , Companyó Xavier , Valero Guillem , Moyano Albert , Rios Ramon
Published: March 2010

A new, easy, and highly enantioselective method for the synthesis of quaternary α‐alkyl‐α‐amino acids based on organocatalysis is reported. The addition of oxazolones to 1,1‐bis(phenylsulfonyl)ethylene is efficiently catalyzed by simple chiral bases or thioureas. The reaction affords α,α‐disubstituted α‐amino acid derivatives with complete C4 regioselectivity and with excellent yields and enantioselectivities. This methodology is complementary to previously reported enantioselective approaches to quaternary α‐amino acids and allows the synthesis of α‐phenyl‐α‐alkyl‐α‐amino acids and α‐tert‐butyl‐α‐alkyl‐α‐amino acids. It has distinct advantages in terms of operational simplicity, enviromentally friendly conditions, and suitability for large‐scale reactions.
Preparation and Characterisation of Super‐Hydrophobic Surfaces
Authors: Crick Colin R. , Parkin Ivan P.
Published: March 2010

The interest in highly water‐repellent surfaces has grown in recent years due to the desire for self‐cleaning surfaces. A super‐hydrophobic surface is one that achieves a water contact angle of 150° or greater. This article explores the different approaches used to construct super‐hydrophobic surfaces and identifies the key properties of each surface that contribute to its hydrophobicity. The models used to describe surface interaction with water are considered, with attention directed to the methods of contact angle analysis. A summary describing the different routes to hydrophobicity is also given.
An Efficient Low‐Temperature Stille–Migita Cross‐Coupling Reaction for Heteroaromatic Compounds by Pd–PEPPSI–IPent
Authors: Dowlut Meenakshi , Mallik Debasis , Organ Michael G.
Published: March 2010

The reactivity of Pd–PEPPSI (Pyridine, Enhanced, Precatalyst, Preparation, Stabilization, and Initiation) precatalysts in the Stille–Migita cross‐coupling reaction between heteroaryl stannanes and aryl or heteroaryl halides was evaluated. In general, Pd–PEPPSI–IPent (IPent=diisopentylphenylimidazolium derivative) demonstrated high efficiency over a variety of challenging aryl or heteroaryl halides with thiophene‐, furan‐, pyrrole‐, and thiazole‐based organostannanes when compared with Pd–PEPPSI–IPr (IPr=diisopropylphenylimidazolium derivative). The transformations proceeded at appreciably lower temperatures (30–80 °C) than triarylphosphine‐based Pd catalysts, improving the scope of this useful carbon–carbon bond‐forming process.
Binding and Inhibition of Copper Ions to RecA Inteins from Mycobacterium tuberculosis
Authors: Zhang Liyun , Xiao Ning , Pan Yan , Zheng Yuchuan , Pan Zhiyun , Luo Zhaofeng , Xu Xiaolong , Liu Yangzhong
Published: March 2010

Protein splicing is a unique post‐translational process in which an intein excises itself from a precursor with the concomitant ligation of flanking sequences. The binding of zinc to intein inhibits protein splicing reversibly and EDTA relieves the inhibition. Copper was found to inhibit protein trans splicing; however, the recovery of intein splicing required both EDTA and TCEP, suggesting a different inhibition mechanism for copper compared to zinc. In this work, we have investigated the binding properties and inhibition effects of copper ions on the RecA intein from Mycobacterium tuberculosis. Both Cu+ and Cu2+ exhibited high binding affinity to inteins, while different binding sites were identified. Cu2+ coordinates to Cys1, the key residue involved in the mechanism of protein splicing, however, Cu+ does not coordinate to cysteine. An in vitro inhibition assay indicated that monovalent Cu+ demonstrates reversible inhibition to protein splicing, and the inhibitory efficiency is comparable to Zn2+. Redox reaction between Cu2+ and cysteine in inteins were observed and the rate constants were determined. The results suggested a dual role for Cu2+ in the inhibition of intein splicing: strong coordination of Cu2+ to key residues (including Cys1) in the intein, and subsequent oxidation of Cys1, the residue required for the N→S acyl shift step in protein splicing. A kinetic study suggested that the coordination could be the major cause of inhibition effect of Cu2+ initially, whereas the redox reaction could play an additional role in inhibition at a later stage.
ChemInform Abstract: Analysis of Electronic Structures and Chemical Bonding of Metal‐Rich Compounds. Part 2. Presence of Dimer (T—T)4‐ and Isolated T2‐ Anions in the Polar Intermetallic Cr5B3‐Type Compounds AE5T3 (AE: Ca, Sr; T: Au, Ag, Hg, Cd, Zn).
Authors: Lee Changhoon , Whangbo Myung‐Hwan , Koehler Juergen
Published: March 2010

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Crystal Structure and Charge Density Analysis of Ca(BH4)2.
Authors: Noritake T. , Aoki M. , Matsumoto M. , Miwa K. , Towata S. , Li H.‐W. , Orimo S.
Published: March 2010

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.