bluuebunny/crossref_metadata_2025_split huggingface dataset:
Construction of a Statistical Evaluation Model Based on Molecular Centrality to Find Retrosynthetically Important Bonds in Organic Compounds
Authors: Tanaka Akio , Kawai Takashi , Matsumoto Tsutomu , Fujii Mihoko , Takabatake Tetsuhiko , Okamoto Hideho , Funatsu Kimito 
Published: October 2008

AbstractFor the purpose of finding retrosynthetically important bonds in a molecule, a new evaluation score has been defined through a logistic regression analysis of known reactions stored in reaction databases. We conceived that reaction center bonds in reaction databases describe one of the most retrosynthetically important bonds for each product structure. The derived statistical equation consists of bond centrality and bond dissociation energy terms. The equation shows that synthetically useful bonds tend to be more central in a molecule and to be weaker bonds. Coefficients in two statistical equations derived from two different reaction data sets are quite similar to each other. From a comparison of molecular complexities and validation with 35 complicated organic compounds, the evaluation equation was proved to be useful. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
Synthesis and NMDA Receptor Affinity of Ring and Side Chain Homologues of Dexoxadrol
Authors: Sax Michael , Fröhlich Roland , Schepmann Dirk , Wünsch Bernhard 
Published: October 2008

AbstractNovel dexoxadrol derivatives with an expanded oxygenheterocycle (1,3‐dioxane instead of 1,3‐dioxolane), an enlarged distance between the two heterocycles, and an additional oxo group in the 4‐position of the piperidine ring were synthesized and pharmacologically evaluated. The synthesis comprises a hetero‐Diels–Alder reaction of imines with Danishefsky's diene (3), followed by a Lewis acid catalyzed conjugate reduction of the resulting dihydropyridones and hydrogenolytic debenzylation. The required aldehydes were synthesized by transacetalization of benzophenone dimethyl acetal (8) with pentane‐1,3,5‐triol (7), butane‐1,2,4‐triol (15), and 4‐benzyloxybutane‐1,3‐diol (31), respectively, and subsequent Swern oxidation. Homodexoxadrols39were synthesized by the Cagliotti method with the use ofp‐toluenesulfonylhydrazide and NaBH4for the removal of the oxo group. The diastereomers were separated and the relative configuration was assigned by X‐ray crystal structure analysis and comparison of spectroscopic and chromatographic data. Receptor binding studies with the radioligand [3H]‐(+)‐MK‐801 demonstrated that an expanded O‐heterocycle, an enlarged distance between the heterocycles, and an additional oxo group led to a considerable loss of affinity towards the phencyclidine binding site of the NMDA receptor.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
1,2,4,5‐Tetrakis(tetramethylguanidino)benzene: Synthesis and Properties of a New Molecular Electron Donor
Authors: Peters Anastasia , Kaifer Elisabeth , Himmel Hans‐Jörg 
Published: October 2008

AbstractThe molecular electron donor 1,2,4,5‐tetrakis(tetramethylguanidino)benzene (ttmgb) was synthesised by reaction between 1,2,4,5‐tetraaminobenzene and 2‐chloro‐1,1′,3,3′‐tetramethylformamidinium chloride. Protonation and oxidation of the molecule were analysed. In the course of titration of initially yellow‐coloured solutions of ttmgb with HCl intense and fully reversible colour changes were observed; the di‐ and tetraprotonated forms are green‐ and blue‐coloured, respectively. The tetraprotonated molecule crystallised with Cl–, and the diprotonated molecule crystallised with PF6– as counterions. Oxidation, which already occurs slowly in air, was followed by CV measurements. Oxidation with I2 leads to deeply green‐coloured solutions, from which purple‐black crystals of (ttmgb)(I3)2 of metallic appearance and a layer structure were obtained. The analysis of the molecular structure shows that the π system has rearranged with loss of the aromatic benzene system. Quantum chemical calculations suggest ttmgb to be an excellent two‐electron donor superior even to the “organic sodium” tetraazafulvalene in the gas phase. However, in polar solvents (modelled with the COSMO model) the situation changes (in line with the experimental results from CV measurements), as the dication of tetraazafulvalene is considerably more solvent stabilised than [ttmgb]2+. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)
Runoff modifications due to the conversion of natural grasslands to forests in a large basin in Uruguay
Authors: Silveira Luis , Alonso Jimena 
Published: October 2008

AbstractUruguay has encouraged the development of the forestry sector since 1989. As a member of the Montreal Process, the country has followed a set of criteria and indicators for the Sustainable Forest Management. The aim of this paper is to describe the studies carried out in a large basin of 2097 km2, located in an area of humid subtropical climate and 1300 mm of long‐term mean annual rainfall, where the conversion of natural grasslands to forests increased up to 540 km2 during the last 15 years. Using data from daily rainfall and streamflow, the study analyses the effects of afforestation on the runoff and water loss. The analysis comprises hydrographs resulting from comparable rainfall events and annual and seasonal streamflow and water loss behaviour, both before afforestation (1975–1993) and during the afforestation period (1994–2008). A statistically significant reduction of runoff volumes (33–43%) and peak flows (59–65%) were identified on storm hydrographs. The annual and seasonal streamflow also showed diminishing tendencies due to the forestry development, whereas the water loss increases. The annual streamflow decreased between 8·2 and 36·5% depending on the annual rainfall totals. The streamflow reduction was higher during spring and summer (25·2–38·4%) and smaller during autumn and winter (15–20·3%). The water loss is expected to increase by 98 mm for the long‐term mean annual rainfall. The resulting information is a valuable input for the Integrated Water Resources Management of the Negro river basin located downstream, where hydroelectric power, rice irrigation and forestry development are supported. Copyright © 2008 John Wiley & Sons, Ltd.
Two decades of new concepts in nitric oxide signaling: From the discovery of a gas messenger to the mediation of nonenzymatic posttranslational modifications
Authors: Martínez‐Ruiz Antonio , Lamas Santiago 
Published: October 2008

AbstractFor the past 20 years, nitric oxide (NO) has established itself as a gaseous free radical with crucial and unpredicted roles in a wide spectrum of biological functions and organisms. We present here a case whereby NO‐mediated signaling can be broadly classified into classical (cGMP‐mediated) and nonclassical, the latter mainly alluding to posttranslational modifications related to NO and its interaction with reactive groups in proteins. © 2008 IUBMB IUBMB Life, 61(2): 91–98, 2009
Bacterial ancient DNA as an indicator of human presence in the past: its correlation with palynological and archaeological data
Authors: Madeja Jacek , Wacnik Agnieszka , Zyga Agata , Stankiewicz Elzbieta , Wypasek Ewa , Guminski Witold , Harmata Krystyna 
Published: October 2008

AbstractPalynological investigation is one of the most important tools for reconstructing past vegetation. Some plants have proved to be relatively sensitive indicators of human activity, but most of them are not specific. In this paper we propose a method which can be used for the verification of phases of anthropogenic impact on vegetation distinguished in pollen diagrams. In this work we adopted the existing molecular methods for tracking bacterial ancient DNA of Bifidobacterium and Bacteroides‐Prevotella (known as human‐ and cow‐specific genetic markers) in palynologically and archaeologically associated sediments. This method can be helpful in determining local human presence, especially in those time periods when pollen analysis has not always been very discriminating (Palaeolithic, Mesolithic) and at sites without archaeological evidence. Copyright © 2008 John Wiley & Sons, Ltd.
Water‐holding capacity of insoluble fibre decreases free water and elevates digesta viscosity in the rat
Authors: Takahashi Toru , Furuichi Yukio , Mizuno Takafumi , Kato Masako , Tabara Aya , Kawada Yuka , Hirano Yoshiyuki , Kubo Kin‐ya , Onozuka Minoru , Kurita Osamu 
Published: October 2008

AbstractBACKGROUND: The relationships between possible physiological properties of insoluble fibre and the viscosity of digesta are poorly understood. The aim of this study was to investigate the effect of insoluble fibres with different water‐holding capacity, swelling, oil‐holding capacity and cation exchange capacity on gastric, small intestinal and caecal contents in rats fed a semi‐purified diet containing either no fibre (control), 50 g kg−1 tossa jute fibre or 50 g kg−1 shiitake fibre.RESULTS: The water‐holding capacity, swelling, oil‐holding capacity and cation exchange capacity of insoluble fibres of tossa jute were higher than those of shiitake (P < 0.001). The order of the viscosities of digesta was control group < shiitake fibre group < tossa jute fibre group in gastric, small intestinal and caecal contents (P < 0.05). The digesta viscosity at a shear rate of 40 s−1 was strongly correlated with the free water content of digesta (r = − 0.89; P < 0.01). The free water content of digesta depended on the water‐holding capacity of insoluble fibres represented as a linear function with negative slope (P < 0.001).CONCLUSION: The viscosity of digesta depends on the free water content, and this is reduced by fibre that holds water and can swell. Copyright © 2008 Society of Chemical Industry
Combining pedometrics, remote sensing and field observations for assessing soil loss in challenging drylands: A case study of Northwestern Somalia
Authors: Omuto C. T. , Vargas R. R. 
Published: October 2008

AbstractSoil loss is a major concern for land managers due to its influence on biomass production, surface water quality and landscape beauty. In Somalia, the risk of soil loss is accelerated by the removal of vegetation, bad land use practices and negative impacts of urbanization. The political upheavals and consequent insecurity in the country are major limitations for detailed database and research in soil loss. This study tested opportunities in pedometrics, remote sensing, limited field data collection and the revised universal soil loss equation (RUSLE) to model the risk of soil loss in northwestern Somalia. The approach successfully predicted the risk of soil loss with accuracy of 79 per cent. It also showed that RUSLE is only relatively accurate and stable in identifying areas with low risk of soil loss and therefore is useful in modelling early warning signs of erosion. About 24 per cent of northwestern Somalia was depicted to have no significant human‐induced soil loss while 68 per cent of the region is in threat of soil loss if no action is taken against the removal of vegetation, land use practices and policies on land tenure systems. About 8 per cent of the area is at high risk of soil loss due to negative effects of urbanization and lack of proper management of steep slopes. It is anticipated that this approach can be integrated in the assessment of soil erosion in areas with poor database. Copyright © 2008 John Wiley & Sons, Ltd.
The effect of natural zeolites and organic fertilisers on the characteristics of degraded soils and yield of crops grown in Western Serbia
Authors: Glisic I. P. , Milosevic T. M. , Glisic I. S. , Milosevic N. T. 
Published: October 2008

AbstractSoils with unfavourable characteristics (pronounced acidity, disturbed structure, compaction, exhaustion, tiredness, etc.) cover a considerable area of Serbia. Specific crops, the fruit ones in particular, are being grown on these soils, yielding, however, considerably lower yields. The paper presents results of two‐year studies on the effect of natural zeolites, organic fertiliser—cattle manure and mineral NPK fertiliser (15:15:15) on soil properties and fruit yield and fruit properties of strawberry and blackberry plants grown on shallow eroded vertisol.The results have shown that the chemical properties of the soil improved with the natural zeolite ‘Agrozel’ (1 kg m−2) +  Manure (1 kg m−2) treatment—resulting in a 0·94‐unit acidity decrease and a 0·58% humus content increase at a 0–20 cm soil depth. Positive but less pronounced changes were also detected at greater soil depths. The strawberry and blackberry cultivation in these soils using the above substances gave rise to a yield increase. In the second year of study, strawberry and blackberry yields increased by 13·15% and 6·27%, respectively. Basic chemical properties of strawberry and blackberry fruits (soluble solids and total acid contents) were not significantly affected by zeolite and organic fertiliser additions to the soil. Copyright © 2008 John Wiley & Sons, Ltd.
Structural glycomics using hydrophilic interaction chromatography (HILIC) with mass spectrometry
Authors: Wuhrer Manfred , de Boer Arjen R. , Deelder André M. 
Published: October 2008

AbstractHydrophilic interaction chromatography (HILIC) with mass spectrometry is a versatile technique for structural glycomics. Glycans are retained by hydrogen bonding, ionic interactions, and dipole–dipole interactions. Glycopeptides as well as glycans with various modifications and reducing‐end labels can be efficiently separated, which often results in the resolution of isobaric species. Chromatography is usually performed with solvent mixtures of organic modifier (often acetonitrile) and volatile (acidic) buffer which are suitable for online‐electrospray ionization‐mass spectrometry. When performed at the nano‐scale, this results in a detection limit for oligosaccharides of approximately 1 femtomol. Alternatively, glycans may be analyzed by offline‐MALDI‐MS(/MS) in both negative‐ion mode and positive‐ion mode, which allows the registration of informative fragment ion spectra from deprotonated species and sodium adducts, respectively. © 2009 Wiley Periodicals, Inc., Mass Spec Rev 28:192–206, 2009
Consumption of oat β‐glucan with or without plant stanols did not influence inflammatory markers in hypercholesterolemic subjects
Authors: Theuwissen Elke , Plat Jogchum , Mensink Ronald P. 
Published: October 2008

AbstractWe have earlier demonstrated that muesli enriched with oat β‐glucan effectively lowered serum LDL cholesterol. Addition of plant stanols further lowered LDL cholesterol. Besides these hypocholesterolemic effects, β‐glucan and plant stanol esters (PSE) may also affect inflammatory processes. Forty‐two mildly hypercholesterolemic subjects randomly consumed for 4 wk (crossover design) control muesli (4.8 g control fiber), β‐glucan muesli (4.8 g oat β‐glucan), or combination muesli (4.8 g oat β‐glucan plus 1.4 g stanol as PSE). Changes in cytokine production (IL‐6, IL‐8, and TNF‐α) of LPS‐stimulated peripheral blood mononuclear cells (PBMC) and whole blood were evaluated, as well as changes in plasma high‐sensitivity (hs)‐CRP. Additionally, changes in expression profiles of 84 genes involved in atherosclerosis metabolism were assessed in isolated PBMC. IL‐6, IL‐8, and TNF‐α production by PBMC and whole blood after LPS stimulation did not differ between the treatments. Also high‐sensitivity C‐reactive protein (hs‐CRP) levels were similar. β‐Glucan consumption did not change gene expression, while only 3 genes (ADFP, CDH5, CSF2) out of the 84 genes from the atherosclerotic risk panel were differentially expressed (p < 0.05) after consumption of PSE. Consumption of β‐glucan with or without PSE did not influence inflammatory parameters in mildly hypercholesterolemic subjects.
Oligomeric procyanidins inhibit cell migration and modulate the expression of migration and proliferation associated genes in human umbilical vascular endothelial cells
Authors: García‐Conesa María‐Teresa , Tribolo Sandra , Guyot Sylvain , Tomás‐Barberán Francisco A. , Kroon Paul A. 
Published: October 2008

AbstractThe consumption of flavan‐3‐ols has been associated with reduced risk of cardiovascular diseases and improvements in vascular function. However, the nature of the flavan‐3‐ols responsible and the mechanisms underlying the vascular responses are not fully understood. We used microarrays to search for molecular changes in response to the exposure to (–)‐epicatechin (EC), procyanidin dimer B2, and a mixture of oligomeric procyanidins in human umbilical vein endothelial cells (HUVECs). No gene expression changes were detected in HUVECs exposed to EC or dimer B2, however, the oligomeric procyanidins induced significant gene expression changes in both resting and TNF‐α‐stimulated cells. In particular, the expression of genes such as ADAMTS1, THBS1, ANGPT2, CYR61, ET‐1, EDG3, and PDE4B involved in endothelial cell migration and proliferation, were substantially over‐represented. Also, exposure to the oligomers arrested the cells at the G0/G1 phase and inhibited cell migration. These data show that human endothelial cells respond to oligomeric procyanidins by exhibiting a less migratory phenotype and by a general modulation of the expression of genes that are associated with key events in the angiogenic process. The molecular changes associated with procyanidin treatment identified in this study are consistent with the beneficial effects of flavan‐3‐ols on vascular function.
Polyphenolic composition of roots and petioles of Rheum rhaponticum L.
Authors: Püssa Tõnu , Raudsepp Piret , Kuzina Kristina , Raal Ain 
Published: October 2008

AbstractIntroductionVarious species of the genus Rheum (Polygonaceae) are known for their high content of medicinally important hydroxyanthraquinones. However, little information is available concerning the polyphenolic composition of garden or dietary rhubarb Rheum rhaponticum L. (R. rhaponticum).ObjectiveDetermination of further polyphenols in the roots and petioles of R. rhaponticum.MethodologyThe dried plant material was extracted with 10‐fold excess (v/w) of methanol and subsequently diluted five times with methanol–water (1:1) and analysed by reversed‐phase liquid chromatography using tandem UV‐photodiode array and mass selective detection (RP‐HPLC‐UV‐ESI/MS2). Polyphenols were identified using either HPLC‐ESI/MS2 data obtained for respective commercial standards or by comparison of a parent ion fragmentation picture with the respective MS2 spectrum from the literature.ResultsThe roots of R. rhaponticum were very rich in various hydroxystilbenes and contained four main substance groups –derivatives of trans‐piceatannol, trans‐resveratrol, trans‐rhapontigenin and trans‐deoxyrhapontigenin. Additionally, pterostilbene acetylglucosides and a number of hydroxyanthraquinones and their glycosides were identified in the root samples. The profile of polyphenols in the petioles of R. rhaponticum was similar to that of the roots but the content of individual substances was remarkably lower. The petioles of the R. rhaponticum additionally contained significant amounts of derivatives of flavonol quercetin, which is a good antioxidant.ConclusionThe study has shown that roots of R. rhaponticum contain a wide variety of hydroxystilbenes and deserve further consideration as a source of medicinally interesting compounds. Copyright © 2008 John Wiley & Sons, Ltd.
Model‐Based Nonlinear Control of Batch Fluidized Bed Dryers
Authors: Li Mingzhong , Duncan Stephen 
Published: October 2008

AbstractControl of a batch fluidized bed dryer is required in many industries. In this paper, the optimization and feedback control of material moisture content in a batch fluidized bed dryer are studied. The optimal operating conditions of the dryer have been found and a generic model control (GMC) strategy has been implemented to achieve a desired drying rate for wet materials. As it is usually impractical to measure moisture content directly, an extended Kalman filter (EKF) observer is used to estimate the moisture content on‐line in order to detect the drying end‐point and to provide a state estimate for feedback control. Studies show that the EKF observer and the GMC controller can provide satisfactory estimation and control of the particle moisture content even if the process model error is significant.
Dynamic Model Analysis of Batch Fluidized Bed Dryers
Authors: Li Mingzhong , Duncan Stephen 
Published: October 2008

AbstractIn this work, a lumped mechanistic model has been developed to describe the heat and mass transfer between solid, gas and bubble phases in a batch fluidized bed dryer. To minimize the computational load, an approximation of the bubble temperature has been made in the model and it is shown that this does not significantly reduce the accuracy of the model. Model parameter sensitivity analysis has indicated that the performance characteristics of a bath fluidized bed dryer are affected not only by the inlet gas superficial velocity and temperature, but also by the features of particle and bubble phases, in particular, the particle and bubble sizes. Experimental validation shows that the proposed lumped dynamic model can be used to predict the particle moisture content and temperature profiles during the drying process in a fluidized bed dryer.
Dissipation of acephate, chlorpyrifos, cypermethrin and their metabolites in a humid‐tropical vegetable production system
Authors: Chai Lian‐Kuet , Mohd‐Tahir Norhayati , Bruun Hansen Hans Christian 
Published: October 2008

AbstractBACKGROUND:High amounts of insecticides are often used in intensive tropical vegetable production systems. Their persistence and residues in vegetables and soils need to be studied to ensure food safety and environmental stability. The dissipation of acephate, chlorpyrifos, cypermethrin and their metabolites was studied in green mustard [Brassica juncea(L.) Coss.] and soils. Two treatments, Impact 75 (acephate) and Agent 505 (cypermethrin plus chlorpyrifos), were applied 4 times at weekly intervals.RESULTS:Dissipation of acephate, chlorpyrifos and cypermethrin in green mustard and topsoils followed first‐order kinetics, with half‐lives of between 1.1 and 3.1 days in green mustard and between 1.4 and 9.4 days in topsoils (26 °C). Higher vapour pressure of insecticides and higher rainfall appeared to stimulate dissipation from the vegetable, with least effect of rainfall on chlorpyrifos. Dissipation rates in the vegetable were faster or similar (cypermethrin) to rates observed for temperate areas. Preharvest intervals of 13, 4 and 3 days were required for acephate, chlorpyrifos, cypermethrin and their metabolites to comply with the tolerance levels. The pesticide dissipation rates in soils varied by less than a factor of 3 between sites. The metabolites methamidophos and TCP derived from acephate and chlorpyrifos amounted to less than 10 and 25% by mass of the parent compounds in soils. Vegetable shading possibly retarded pesticide degradation in soil.CONCLUSION:The dissipation of pesticides and their metabolites in the vegetable was rapid and faster than the dissipation in temperate climates. The degradation rates of pesticides in the soil were equal to or slightly faster than the degradation rates in temperate soils. Copyright © 2008 Society of Chemical Industry