bluuebunny/crossref_metadata_2025_split huggingface dataset:
Evaluation and Impact Assessment of Meteorological Drought Characteristics over West Africa
Authors: Ogolo Emmanuel O. , Ojo Olusola S. , Akinwande Dolapo D. 
Published: May 2024

When a region receives little precipitation for an extended period of time, droughts occur. The environmental and socioeconomic effects it has make it one of the most devastating natural disasters that can happen to a location. For the purpose of enhancing early warning systems and lowering the risk of disasters caused by drought, research into the effects of meteorological drought characteristics on a location is crucial. Therefore, this study uses the Standard Precipitation Index (SPI) and Standard Precipitation Evapotranspiration Index (SPEI) to assess the effects of meteorological drought characteristics over West Africa. The study area includes West Africa's Saharan, Sahelian, and Sudanese climate zones, and Copernicus Service provided the meteorological information (temperature and precipitation). The data was based on four monthly time scales (3, 6, 12, and 24) and covered 42 years (1979-2021). The data were analyzed and the characteristics of the drought were assessed using SPI and SPEI. According to the results, there was extreme drought between the years 1982 to 1985 and year 2021. However, 1982 was the year with the highest incidence of drought, across nearly all the stations. Additionally, it was found that location 4 experiences drought continuously from 1982 to 2021, whereas all other locations experienced absence of drought for a short period of time. Comparing the SPI and SPEI results, SPI produced results for the drought analysis that were comparable to those of SPEI for each of the monthly time scales for all locations. Majority of the locations will likely experience drought every seven to ten years, with location 4 possibly experiencing at least a mild drought every year. Finally, this study suggests that, in light of the time-scales analysis and drought classification for each location, SPI and SPEI represent the most suitable measures for the region's drought monitoring.
Regulation of Non‐Infectious Lung Injury, Inflammation, and Repair by the Extracellular Matrix Glycosaminoglycan Hyaluronan
Authors: Jiang Dianhua , Liang Jiurong , Noble Paul W. 
Published: February 2010

AbstractAn important hallmark of tissue remodeling is the dynamic turnover of extracellular matrix (ECM). ECM performs a variety of functions in tissue repair including scaffold formation, modulation of fluid dynamics, and regulating cell behavior. During non‐infectious tissue injury ECM degradation products are generated that acquire signaling functions not attributable to the native precursor molecules. Hyaluronan (HA) is a non‐sulfated glycosaminoglycan which is produced in great abundance following tissue injury. It exists both in a soluble form and as side chains on proteoglycans. HA has critical roles in development as well as a variety of biological processes including wound healing, tumor growth and metastasis, and inflammation. HA fragments share structural similarities with pathogens and following tissue injury can be recognized by innate immune receptors. Elucidating the protean roles of HA in tissue injury, inflammation, and repair will generate new insights into mechanisms of diseases characterized by chronic inflammation and tissue remodeling. Anat Rec, 2010. © 2010 Wiley‐Liss, Inc.
Stereoselective Synthesis and Antiviral Activity of (1E,2Z,3E)‐1‐(Piperidin‐1‐yl)‐1‐(arylhydrazono)‐2‐[(benzoyl/benzothiazol‐ 2‐oyl)hydrazono]‐4‐(aryl1)but‐3‐enes
Authors: Abdel‐Aziza Hatem A. , Abdel‐Wahab Bakr F. , Badria Farid A. 
Published: February 2010

AbstractThe reaction of benzoyl hydrazine 1a or benzothiazole‐2‐carbohydrazide 1b with 2‐oxo‐N‐arylpropanehydrazonoyl chlorides 2a–d yielded (1Z,2E)‐2‐[(benzoyl/benzothiazol‐2‐oyl)hydrazono]‐N‐(aryl)propanehydrazonoyl chlorides 3a–e. The reaction of 3a–c with sodium benzenesulphinate furnished sulphones 5a–c while the reaction of 5d, e with hydroxyl amine afforded hydroxomoyl derivatives 6a, b. The one‐pot sterioselective reaction of N‐(aryl)propanehydrazonoyl chlorides 3 with certain aromatic aldehydes in the presence of piperidine resulted in the formation of (1E,2Z,3E)‐1‐(piperidin‐1‐yl)‐1‐(arylhydrazono)‐2‐[(benzoyl/benzothiazol‐2‐oyl)hydrazono]‐4‐(aryl1)‐but‐3‐enes 7a–g. X‐ray analysis of piperidinyl amidrazone 7g showed a conversion of its geometrical structure with respect to that of compound 3 and confirmed the stereoselectivity of the latter reaction. The piperidinyl amidrazones 7a–g possessed a significant antiviral activity against herpes simplex viruses (HSV‐1). Compound 7d reduced the number of viral plaques of herpes simplex type‐1 (HSV‐1) by 67%, with respect to the effect of reference drug Aphidicolin.
Synthesis of Naphtho[1,8‐bc]pyran Derivatives and Related Compounds through Hydroxy Group Directed CH Bond Cleavage under Rhodium Catalysis
Authors: Mochida Satoshi , Shimizu Masaki , Hirano Koji , Satoh Tetsuya , Miura Masahiro 
Published: February 2010

AbstractThe straightforward and efficient synthesis of naphtho[1,8‐bc]pyran derivatives and related polycyclic compounds is achieved by the rhodium‐catalyzed oxidative coupling of 1‐naphthols or other phenolic and alcoholic substrates with alkynes. In these annulation reactions, the hydroxy groups effectively act as the key function for the regioselective CH bond cleavage.
Ion–Molecule Reactions of “Rollover” Cyclometalated [Pt(bipy−H)]+ (bipy=2,2′‐bipyridine) with Dimethyl Ether in Comparison with Dimethyl Sulfide: An Experimental/Computational Study
Authors: Butschke Burkhard , Ghassemi Tabrizi Shadan , Schwarz Helmut 
Published: February 2010

AbstractThe ion–molecule reactions of dimethyl ether with cyclometalated [Pt(bipy−H)]+ were investigated in gas‐phase experiments, complemented by DFT methods, and compared with the previously reported ion–molecule reactions with its sulfur analogue. The initial step corresponds in both cases to a platinum‐mediated transfer of a hydrogen atom from the ether to the (bipy−H) ligand, and three‐membered oxygen‐ and sulfur‐containing metallacycles serve as key intermediates. Oxidative CC bond coupling (“dehydrosulfurization”), which dominates the gas‐phase ion chemistry of the [Pt(bipy−H)]+ ion with dimethyl sulfide, is practically absent for dimethyl ether. The competition in the formation of C2H4 and CH2X (X=O, S) in the reactions of [Pt(bipy−H)]+ with (CH3)2X (X=O, S) as well as the extensive H/D exchange observed in the [Pt(bipy−H)]+/(CH3)2O system are explained in terms of the corresponding potential‐energy surfaces.
Origin of the Unusual Properties of Aun(BO2) Clusters
Authors: Götz Matthias , Willis Mary , Kandalam Anil K. , Ganteför Gerd F. , Jena Purusottam 
Published: February 2010

AbstractWe report the discovery of a new class of clusters consisting of Aun(BO2) that forms during the oxygenation of gold clusters when boron nitride is used as insulation in a pulsed‐arc cluster ion source (PACIS). Photoelectron and mass spectroscopy of these clusters further revealed some remarkable properties: instead of the expected AunOm peaks, the mass spectra contain intense peaks corresponding to Aun(BO2) composition. Some of the most predominant features of the electronic structure of the bare Au clusters, namely even–odd alternation in the electron affinity, are preserved in the Aun(BO2) species. Most importantly, Aun(BO2) [odd n] clusters possess unusually large electron affinity values for a closed‐shell cluster, ranging from 2.8–3.5 eV. The open‐shell Aun(BO2) [even n] clusters on the other hand, possess electron affinities exceeding that of F, the most electronegative element in the periodic table. Using calculations based on density functional theory, we trace the origin of these species to the unusual stability and high electron affinity of the BO2 moiety. The resulting bond formed between BO2 and Aun clusters preserves the geometric and electronic structure of the bare Aun clusters. The large electron affinity of these clusters is due to the delocalization of the extra electron over the Aun cluster.
Murine CXCR3+CD27bright NK cells resemble the human CD56bright NK‐cell population
Authors: Marquardt Nicole , Wilk Esther , Pokoyski Claudia , Schmidt Reinhold E. , Jacobs Roland 
Published: February 2010

AbstractHuman NK cells can be subdivided into CD56dim and CD56bright NK cells, which exhibit different phenotypical and functional characteristics. As murine NK cells lack CD56 or a distinct correlate, direct comparative studies of NK cells in mice and humans are limited. Although CD27 is currently proposed as a feasible subset marker in mice, we assume that the usage of this marker alone is insufficient. We rather investigated the expression of the chemokine receptor CXCR3 for its suitability for distinguishing murine NK‐cell subsets with simultaneous consideration of CD27. Compared with CXCR3− NK cells, exerting stronger cytotoxic capability, CXCR3+ NK cells displayed an activated phenotype with a lower expression of Ly49 receptors, corresponding to human CD56bright NK cells. Also in common with human CD56bright NK cells, murine CXCR3+ NK cells exhibit prolific expansion as well as robust IFN‐γ, TNF‐α and MIP‐1α production. We additionally demonstrated changes in both CXCR3 and CD27 expression upon NK‐cell activation. In summary, CXCR3 serves as an additional applicable marker for improved discrimination of functionally distinct murine NK‐cell subsets that comply with those in humans.
Dendritic Zirconium‐Peroxotungstosilicate Hybrids: Synthesis, Characterization, and Use as Recoverable and Reusable Sulfide Oxidation Catalysts
Authors: Jahier Claire , Mal Sib Sankar , Kortz Ulrich , Nlate Sylvain 
Published: February 2010

AbstractA series of dendrimer‐containing polyoxometalates(DENDRIPOMs) was synthesized by coupling zirconium‐peroxotungstosilicate [Zr2(O2)2(SiW11O39)2]12– with ammonium dendrons by electrostatic bonding. These DENDRIPOMs were successfully characterized by standard physicochemical techniques (e.g. IR and NMR spectroscopy and MS), and they represent the first examples of dendritic POMs based on zirconium‐substituted polytungstates. The data obtained are consistent with structures in which the anionic POM is surrounded by cationic ammonium dendrons. In contrast to the potassium salt of [Zr2(O2)2(SiW11O39)2]12–, the dendritic counterparts are soluble in common organic solvents, an important feature for the use of DENDRIPOMs in homogeneous catalysis. Our DENDRIPOMs are stable, efficient, recoverable, and reusable catalysts for the oxidation of sulfides in aqueous/CDCl3 biphasic media, with hydrogen peroxide as the oxidant, in contrast to their nondendritic n‐butyl ammonium counterpart. Two cycles of catalytic reactions were performed without any appreciable loss of activity. We also discovered that the reaction kinetics and selectivity of theDENDRIPOMs are influenced by the structure of the countercation used.
Essential oils and volatiles: sample preparation and analysis. A review.
Authors: Rubiolo P. , Sgorbini B. , Liberto E. , Cordero C. , Bicchi C. 
Published: February 2010

AbstractThis article is a short overview of the state of the art in essential oil analysis. Several aspects of the analysis of essential oils and volatile fraction of vegetable matrices are here critically discussed. The following topics are dealt with: steam distillation, hydrodistillation and headspace sampling for sample preparation, and fast‐GC, fast‐GC–qMS analysis, enantioselective GC, multidimensional GC techniques and GC–isotopic ratio mass spectrometry (GC–IRMS) for analysis and quantitation.
Physiologically based modeling of p‐tert‐octylphenol kinetics following intravenous, oral or subcutaneous exposure in male and female Sprague–Dawley rats
Authors: Hamelin G. , Haddad S. , Krishnan K. , Tardif R. 
Published: February 2010

AbstractThe objective of this study was to develop a physiologically based pharmacokinetic (PBPK) model for p‐tert‐octylphenol (OP) for understanding the qualitative and quantitative determinants of its kinetics in Sprague–Dawley rats. Compartments of the PBPK model included the liver, richly perfused tissues, poorly perfused tissues, reproductive tissues, adipose tissue and subcutaneous space, in which OP uptake was described as a blood flow‐ or a membrane diffusion‐limited process. The PBPK model successfully simulated previously published data on blood and tissue OP concentrations in Sprague–Dawley rats following oral, intravenous (i.v.) or subcutaneous (s.c.) routes. The model predicted that OP concentrations would reach 6.8, 13.8 and 27.9 ng ml−1 (male) and 7.2, 14.7 and 31.4 ng ml−1 (female), 4 h after a single i.v. dose of 2, 4 and 8 mg kg−1, respectively. The model also predicted that OP concentrations would reach 53.3, 134.8 and 271.2 ng ml−1 (male) and 87.4, 221.4 and 449.7 ng ml−1 (female) 4 h after a single oral dose (50, 125 and 250 mg kg−1) and that, 4 h after a single s.c. dose (125 mg kg−1), OP concentrations would reach 111.3 ng ml−1 (male) and 121.6 ng ml−1. A marked sex difference was seen in blood and tissue OP concentrations. This was reflected in the model by a gender‐specific maximal velocity of metabolism (Vmax) that was higher (1.77×) in male than in female rats. Further studies are required to elucidate the mechanism underlying the gender differences and to evaluate whether that is also observed in humans. Copyright © 2010 John Wiley & Sons, Ltd.
Molecular design of a “molecular syringe” mimic for metal cations using a 1,3‐alternate calix[4]arene cavity
Authors: Zheng Xiaoyan , Wang Xueye , Shen Keqi , Wang Nuanqing , Peng Yueming 
Published: February 2010

AbstractThe chemically switchable actions well imitate the function of a “molecular syringe,” has been studied in theory using the 1,3‐alternate calix [4]arene bearing a nitrogen‐containing crown cap at one side and a bis(ethoxyethoxy) group at another side by the π‐basic calixtube as a pipette and the crown ring as a rubber cap. The model is characterized by geometry optimization using density functional theory (DFT) at B3LYP/6‐31G level. The obtained optimized structures are used to perform natural bond orbital (NBO) and frequency analysis. The electron‐donating heteroatoms: O and N offer lone pair electrons to the contacting RY* (1‐center Rydberg) or LP* (1‐center valence antibond lone pair) orbitals of K+, Ag+. The results indicate that when the nitrogen atom in the crown ring is protonated, K+ and Ag+ will be pushed out to the bis(ethoxyethoxy) side through a π‐basic calixtube. When the nitrogen·H+ in the crown ring is deprotonated, K+ and Ag+ are sucked back to the crown‐capped side again. In the course of the coordination, both the intermolecular electrostatic interactions and the cation‐π interactions between the metal ion and π‐orbitals of the two pairs facing inverted benzene rings play a significant role. It is believed that this prototype of a “molecular syringe” is a novel molecular architecture for the action of metal cations. © 2010 Wiley Periodicals, Inc. J Comput Chem 2010
Synthesis and reactions of 4‐benzoyl‐1,5‐diaryl‐1H‐pyrazole‐3‐carbonyl chlorides with various semi‐ and thiosemicarbazides
Authors: Korkusuz Elif , Yıldırım Ismail 
Published: February 2010

Abstract
magnified imageThe 1H‐pyrazole‐3‐carboxylic acids 2 were converted via reactions of their acid chlorides 3 with some semi‐ and thiosemicarbazide derivatives into the corresponding new phenylsemi‐ and thiosemicarbazides 4a, 4b, 4c, 4d, 4e, 6, 5‐(pyrazol‐3‐yl)‐4H‐1,2,4‐triazol‐3‐thiones 5a, 5b, and 2‐(pyrazol‐3‐yl)‐1,3,4‐thiadiazol 7 derivatives, in good yields (45‐97%, respectively). The reactions of 4a,4c,4e with Lawesson reagent lead to the products 6 and 7 formation. The structures of these newly synthesized compounds were determined from the IR, 1H‐ and 13C‐NMR spectroscopic data and elemental analyses. J. Heterocyclic Chem., (2010).
Impact of postharvest methyl jasmonate treatment on the volatile composition and flavonol content of strawberries
Authors: de la Peña Moreno Fernando , Blanch Gracia Patricia , Flores Gema , Ruiz del Castillo María Luisa 
Published: February 2010

AbstractBACKGROUND:Although strawberry aroma is very complex, certain compounds have been described as main contributors, i.e. furanones, aldehydes, alcohols, sulfur compounds and particularly methyl and ethyl esters. In addition, strawberries possess potent antioxidant activity because of their high content of phenolic compounds. Among them, flavonols are highlighted as important antioxidant compounds in strawberry. The objective of this study was to assess the effect of methyl jasmonate (MJ) on the composition of the major contributors to aroma and on the content of certain flavonols in strawberry fruits.RESULTS:The levels of all studied volatile compounds were significantly affected by MJ treatment, though the individual effect differed according to the specific compound considered. Most of them increased significantly (P< 0.05), except methyl butanoate, which always showed higher levels in untreated strawberries. In contrast to aroma compounds, the change in the concentration of flavonols (i.e. myricetin, quercetin and kaempferol) was not significant in MJ‐treated strawberries. Considering the health‐promoting activity of these compounds, further investigations on the experimental conditions related to the treatment are required to control flavonol bioformation by means of MJ.CONCLUSION:The exogenous application of MJ vapour to strawberry enhances, in general, the production of the most relevant aroma‐active compounds. On the contrary, MJ treatment does not appear to influence the levels of myricetin, quercetin and kaempferol. Thus postharvest MJ treatment is proposed as an approach to obtain improved strawberry fruits in terms of sensory quality and health‐promoting properties. Copyright © 2010 Society of Chemical Industry
Molecular Characteristics of Poly(N‐isopropylacrylamide) Separated from Nanocomposite Gels by Removal of Clay from the Polymer/Clay Network
Authors: Haraguchi Kazutoshi , Xu Yingjia , Li Guang 
Published: February 2010

AbstractThe extraordinary mechanical and swelling/deswelling properties of nanocomposite (NC) gels are attributed to their unique organic (polymer)/inorganic (clay) network structure. In this study, poly(N‐isopropylacrylamide) (PNIPA) was successfully separated from an NC gel network by decomposing the clay (hectorite) using hydrofluoric acid (HF). A very low HF concentration (0.2 wt.‐%) was adequate for the decomposition of the clay without causing any damage to PNIPA. The separated PNIPA had a high $\overline M _{\rm w}$ (=5.5 × 106 g · mol−1). Also, $\overline M _{\rm w}$ was almost constant regardless of the clay concentration (Cclay = 1–25 × 10−2 mol · l−1), even though the properties of the NC gel varied widely over this Cclay range. Comparisons of NC gels, PNIPA, and SiO2‐NC gels indicated that the clay platelets specifically play an important role in NC gels.magnified image
Photoinduced Microphase Separation in Block Copolymers: Exploring Shape Incompatibility of Mesogenic Side Groups
Authors: Zhao Yi , Tong Xia , Zhao Yue 
Published: February 2010

AbstractPhotoinduced microphase separation in block copolymers (BCP) was achieved for the first time, using a rationally designed diblock copolymer composed of two side‐chain liquid crystalline polymers (SCLCP). The miscibility of the two blocks was promoted by the miscibility between the two types of mesognic side groups, while upon UV exposure inducing the trans–cis isomerization of azobenzene mesogens on one SCLCP, the shape incompatibility of bent cis isomers with an ordered liquid crystalline phase drove the separation of the two blocks resulting in a microphase separated morphology. This result shows the perspective of using light to process and organize BCP morphology and related nanostructures in a lithography‐free manner.magnified image
Natural bond orbital (NBO) analysis of the angular group induced bond alternation (AGIBA) substituent effect
Authors: Oziminski Wojciech P. , Krygowski Tadeusz M. 
Published: February 2010

AbstractThe geometries, natural charges, and resonance structures of 11 monosubstituted benzene derivatives were analyzed at the B3LYP/6‐311++G(d,p) and HF/6‐311++G(d, p) levels of theory. The following angular substituents were chosen: OCH3, CH2CH3, OH, SH, NHCH3, NHNH2, NO, CHCH2, NCH2, NNH, and CHO. The analysis of resonance structures was performed by using two different methodologies: harmonic oscillator stabilization energies (HOSE) and natural resonance theory (NRT). Also, the natural bond orbital (NBO) donor–acceptor stabilization energies for different resonance structures were calculated. We found that for all the substituents, the purely geometric resonance stabilization parameter (HOSE) is linearly correlated with quantum chemically derived resonance structure weight (NRT) of a given structure. Also, the calculations provide qualitative support for the earlier assumption of a through space angular group induced bond alternation (AGIBA) effect. Copyright © 2010 John Wiley & Sons, Ltd.
A design to prevent floating within the N scale of nucleophilicity
Authors: Bentley T. William 
Published: February 2010

AbstractTwo nucleophilicity scales (N′ and N″) including 96 nucleophiles, spanning 1017 in rate constant, have been constructed directly from experimental rate constants for reactions of nucleophiles with dianisyl (log k = N′) or dimethylaminobenzhydrylium (log k = N″) cations in dichloromethane at 20 °C. The two scales are linked/unified by the formula: N′ − N″ = 6.6. In contrast, published procedures (H. Mayr et al. J. Am. Chem. Soc. 2001, 123, 9500, and later work) involve 23 benzhydrylium cations and over 200 adjustable parameters obtained from the equation log k = s(E + N), where k is the rate constant, E is an electrophilicity parameter and s is a nucleophile‐specific sensitivity parameter. The definitions of N′ and N″ avoid a floating N scale, i.e. having less than the usual attachment to fixed reference points. New equations, log k = (E + sN′) or log k = (E + sN″), where s is now an electrophile‐specific parameter, are then used to correlate over 350 second‐order rate constants for reactions of other benzhydrylium cations with nucleophiles. For weaker, less polar, nucleophiles, s ∼ 1 and the new E and N′ parameters are in satisfactory agreement with published data for E and N. For more polar nucleophiles, s ≠ 1 and values of N − N″ vary by five log units. Copyright © 2010 John Wiley & Sons, Ltd.
Deep X‐ray Lithography for Direct Patterning of PECVD Films
Authors: Costacurta Stefano , Malfatti Luca , Patelli Alessandro , Falcaro Paolo , Amenitsch Heinz , Marmiroli Benedetta , Grenci Gianluca , Piccinini Massimo , Innocenzi Plinio 
Published: February 2010

AbstractAn advanced lithographic technique which is based on direct writing of thin films by hard X‐rays has been developed. Silica hybrid organic–inorganic films have been deposited by radio frequency plasma‐enhanced chemical vapour deposition and have been patterned using deep X‐ray lithography with synchrotron light. The exposure to high energy photons removed the organic groups in the films and induced densification of the silica network. The films, after lithographic writing, can be easily chemically etched to obtain well‐defined patterns of high quality. By tuning the exposure dose it is possible modulating the structure and the properties of the final material. The overall lithography process can be achieved in two steps, writing by X‐rays and chemical etching, therefore employing the hybrid film directly as resist without employing any other intermediate step. The films and the patterned structures have been characterized by ellipsometric spectroscopy, scanning electron microscopy, atomic force microscopy, contact angle measurements, Fourier transform infrared spectroscopy, infrared imaging and Rutherford backscattering.magnified image