bluuebunny/crossref_metadata_2025_split huggingface dataset:
Rate limiting electrophilic attack in nitrosation of aminoguanidine
Authors: Fernández I. , Hervés P. , Parajó M. 
Published: February 2009

AbstractNitrosation reaction of aminoguanidine (AG) has been studied. The nitrosation rate is first‐order with respect to both the AG and acid concentration. The absence of general base catalysis, the existence of catalysis by nucleophilic anions (X−and SCN−) and the observed inverse deuterium isotope effect lead us to propose a mechanism for AG nitrosation similar to that which operates in the case of amines, in which the electrophilic attack of the nitrosating agents is the rate determining step. From this mechanism, we were able to obtain the values of the rate constants for the nitrosation process. We have found that unlike the other amines, the protonated form of AG is the reactive species. This situation becomes possible for AG because protonation of guanidines occurs mostly on the iminic nitrogen, and this may be the reason for the lower reactivity of this amine. Copyright © 2009 John Wiley & Sons, Ltd.
Structure and function of natural and synthetic signalling molecules in parasitic weed germination
Authors: Zwanenburg Binne , Mwakaboko Alinanuswe S , Reizelman Anat , Anilkumar Gopinathan , Sethumadhavan Divakaramenon 
Published: February 2009

AbstractThe structures of naturally occurring germination stimulants for seeds of the parasitic weeds Striga spp. and Orobanche spp. are described. The bioactiphore in this strigolactone family of stimulants is deduced from a structure–activity relationship and shown to reside in the CD part of the stimulant molecule. A molecular mechanism for the initial stages of seed germination is proposed. The influence of stereochemistry on the stimulant activity is significant. Combining this molecular information leads to a model for the design of synthetic strigolactones. Nijmegen‐1 is a typical example of a highly active, newly designed synthetic stimulant. The occurrence of natural stimulants not belonging to the strigolactone family, such as cotylenin and parthenolide, is briefly described. The biosynthesis of natural strigolactones from β‐carotene is analysed in terms of isolated and predicted stimulants. This scheme will be helpful in the search for new strigolactones from root exudates. Protein fishing experiments to isolate and characterise the receptor protein using biotin‐labelled GR 24 are described. A receptor protein of 60 kD was identified by this method. Nijmegen‐1 has been tested as a suicidal germination agent in field trials on tobacco infested by Orobanche ramosa L. The preliminary results are highly rewarding. Finally, some future challenges in synthesis are described. These include synthesising new natural and synthetic stimulants and establishing the molecular connection between strigolactones as germination stimulants, as the branching factor for arbuscular mycorrhizal fungi and as an inhibitor of shoot branching. Copyright © 2009 Society of Chemical Industry
A major QTL for resistance of rice to the parasitic plant Striga hermonthica is not dependent on genetic background
Authors: Swarbrick Philip J , Scholes Julie D , Press Malcolm C , Slate Jon 
Published: February 2009

AbstractBACKGROUND: The use of Striga‐resistant germplasm is likely to be a cost‐effective control strategy for preventing loss of yield owing to Striga. Previously, the authors identified quantitative trait loci (QTL) for resistance in rice to Striga hermonthica (Del.) Benth. in backcross inbred lines (BILs) derived from a cross between two cultivars Nipponbare and Kasalath. It is essential to validate QTL in different environments and/or genetic backgrounds to develop molecular markers linked to resistance QTL for use in marker‐assisted selection (MAS) programmes. This study aimed to establish whether a large‐effect Kasalath‐derived resistance QTL allele on chromosome 4 of rice also conferred resistance in a different mapping population derived from a cross between Koshihikari and Kasalath, and to identify any further Striga resistance QTL.RESULTS: Three Striga resistance QTL were detected in Koshihikari–Kasalath BILs, two of which were derived from the Kasalath allele and one from the Koshihkari allele. The largest QTL (Kasalath allele) explained 16% of the variation in the mapping population and was located on chromosome 4. Comparison between these data and those of the authors' previous analysis revealed that the confidence intervals of the chromosome‐4 QTL in the Nipponbare–Kasalath cross and the Kasalath–Koshihikari cross overlapped between 6.5 Mbp and 8 Mbp on the physical rice genome assembly.CONCLUSION: This study has both verified and narrowed down the position of a Striga resistance QTL of major effect, and demonstrated that it may be a tractable target for MAS. Copyright © 2009 Society of Chemical Industry
Strigolactones: structures and biological activities
Authors: Yoneyama Koichi , Xie Xiaonan , Yoneyama Kaori , Takeuchi Yasutomo 
Published: February 2009

AbstractStrigolactones released from plant roots induce seed germination of root parasitic weeds, witchweeds (Striga spp.) and broomrapes (Orobanche spp.), and hyphal branching of symbiotic arbuscular mycorrhizal (AM) fungi. In addition to these functions in the rhizosphere, strigolactones have recently been shown to be a novel class of plant hormones regulating shoot outgrowth. The natural strigolactones identified so far have the common C–D ring moiety, which is thought to be the essential structure for exhibiting biological activity. The introduction of substitutions on the A–B ring moiety of 5‐deoxystrigol, the basic strigolactone, affords various strigolactones, e.g. hydroxylation on C‐4, C‐5 and C‐9 leads to orobanchol, strigol and sorgomol respectively. Then, acetylation and probably other derivatisations of these hydroxy‐strigolactones would occur. Although the C‐2′‐(R) stereochemistry was thought to be an important structural feature for potent germination stimulation activity, 2′‐epi‐strigolactones were found in root exudates of tobacco, rice, pea and other plant species, indicating that at least some plants produce both epimers. Copyright © 2009 Society of Chemical Industry
Formation of CdSxTe1–x at the p‐n junction of CdS‐CdTe solar cells
Authors: Hädrich Mathias , Kraft Christian , Metzner Heinrich , Reislöhner Udo , Löffler Christiane , Witthuhn Wolfgang 
Published: February 2009

AbstractThe formation of ternary CdSxTe1–x alloys during CdTe solar cell production is quantitatively investigated using optical and quantum efficiency measurements. Both the diffusion of sulphur into the CdTe and of tellurium into the CdS film are analysed in the context of film thicknesses and the activation step used in CdTe solar cell processing. We present a method of determining the tellurium content in the CdS layer from EQE measurements. The tellurium content is limited to small values and depends on the CdS thickness. A CdSxTe1–x phase of several 100 nm thickness is generated in the CdTe film during the activation step. This phase changes the optical bandgap in the depletion region and gains importance in cells with thin absorbers. The comparison of solar cells with and without CdS layer illustrates the crucial role of the CdS buffer layer for the p‐n junction. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
High‐temperature electrical properties of CdTe:Bi single crystals
Authors: Fochuk P. , Obedzynska Yu. , Armani N. , Zakharuk Z. , Yuriychuk I. , Kopach O. , Panchuk O. 
Published: February 2009

AbstractAt first the experimental results of detailed Hall effect measurements at high‐temperature defect equilibrium under Cd/Te vapor pressure in CdTe single crystals were obtained. They indicate that at these conditions Bi forms in CdTe crystals mainly BiCd donor centers. The analysis of the free electron density temperature dependencies allows to conclude that up to 800 K the electrons of dopant atoms define the sample's electrical properties. The native donor point defects begin to influence the electro‐neutrality condition above this temperature. The research of high‐temperature electrical properties of Bi‐doped CdTe samples shows that the real electrical active Bi content in the investigated crystals is ∼1017 at/cm3. The electron density dependencies vs PCd, modeled at constant temperatures (500‐900°C), in the assumption of deep Bi donor (EV+0.71 eV) are in good agreement with experiment. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Crystal structures, thermal expansion and phase transitions of mixed Pr1–xLaxAlO3 perovskites
Authors: Basyuk Tetyana , Vasylechko Leonid , Syvorotka Igor , Schmidt Ulrike , Trots Dmytro , Niewa Rainer 
Published: February 2009

AbstractThe crystal structures, thermal expansion and phase transitions of mixed Pr1–x Lax AlO3 perovskites have been examined by using an in situ high resolution X‐ray powder diffraction technique applying synchrotron radiation in a wide temperature range of 12–1173 K. At room temperature all samples in the PrAlO3–LaAlO3 pseudo‐binary system adopt the rhombohedral perovskite‐like structure. At elevated temperatures, all Pr1−x Lax AlO3 compositions undergo continuous phase transitions from rhombohedral to cubic structures. The sequence of the low‐temperature (LT) phase transformations R $\bar 3$ c ↔Imma ↔C2/m has been observed in Pr1–x Lax AlO3 samples. Temperatures of HT and LT phase transitions in Pr1–x Lax AlO3 decrease with decreasing Pr content. Crystal structure parameters for all compositions Pr1–x Lax AlO3 have been determined. Based on in situ powder diffraction and DTA/DSC data, the phase diagram of the PrAlO3–LaAlO3 pseudo‐binary system has been constructed. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Analysis of lignans in Schisandra chinensis and rat plasma by high‐performance liquid chromatography diode‐array detection, time‐of‐flight mass spectrometry and quadrupole ion trap mass spectrometry
Authors: Lou Ziyang , Zhang Hai , Gong Chungui , Zhu Zhenyu , Zhao Liang , Xu Yuanjie , Wang Bin , Zhang Guoqing 
Published: February 2009

AbstractHigh‐performance liquid chromatography/diode‐array detection (HPLC/DAD), time‐of‐flight mass spectrometry (HPLC/TOFMS) and quadrupole ion trap mass spectrometry (HPLC/QIT‐MS) were used for separation, identification and structural analysis of lignans in Schisandra chinensis and rat plasma after oral administration of the herbal extract. Six lignans in Schisandra chinensis extract were identified unambiguously by comparing the retention time, their characteristic ultraviolet (UV) absorption and accurate mass measurement. A formula database of known lignans in Schisandra chinensis was established, against which the other 15 lignans were identified effectively based on the accurate extract masses and formulae acquired by HPLC/TOFMS. In order to distinguish the isomers, multi‐stage mass spectrometry (ion trap mass spectrometry, MSn) was also used. The fragmentation behavior of the lignans in the ion trap mass spectrometer was studied by the six lignan standards, and their fragmentation rules in MSn spectra were summarized. These deduced fragmentation rules of lignans were successfully implemented in distinguishing the three groups of isomers in Schisandra chinensis by HPLC/QIT‐MS. By using the three different analytical techniques, 21 lignans in Schisandra chinensis were identified within 30 min. After oral administration of the extract, 11 lignans in rat plasma were detected and identified by comparing their retention time, characteristic UV absorption and accurate mass measurement of peaks in HPLC/TOFMS chromatograms of the herbal extract. Finally, HPLC/TOFMS fingerprints of Schisandra chinensis in vitro and rat plasma in vivo were established. It is concluded that a rapid and effective method based on three analytical techniques for identification of chemical components was established, which is useful for rapid identification of multiple components in Schisandra chinensis in vitro and in vivo. In addition, it can provide help for further pharmacology and action mechanism study of lignans in Schisandra chinensis. Copyright © 2009 John Wiley & Sons, Ltd.
Evaluation of matrix‐assisted laser desorption/ionization (MALDI) preparation techniques for surface characterization of intact Fusarium spores by MALDI linear time‐of‐flight mass spectrometry
Authors: Kemptner Jasmin , Marchetti‐Deschmann Martina , Mach Robert , Druzhinina Irina S. , Kubicek Christian P. , Allmaier Günter 
Published: February 2009

AbstractUnambiguous identification of mycotoxin‐producing fungal species as Fusarium is of great relevance to agriculture and the food‐producing industry as well as in medicine. Protein profiles of intact fungal spores, such as Penicillium, Aspergillus and Trichoderma, derived from matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry (MALDI‐TOF MS) were shown to provide a rapid and straightforward method for species identification and characterization. In this study, we applied this approach to five different Fusarium spp. strains which are known to affect the growth of different grain plants. To obtain a suitable MALDI matrix system and sample preparation method, thin‐layer, dried‐droplet and sandwich methods and several MALDI matrices, namely CHCA, DHB, FA, SA and THAP dissolved in various solvent mixtures (organic solvents such as ACN, MeOH, EtOH and iPrOH and for the aqueous phase water and 0.1% TFA), were evaluated in terms of mass spectrometric pattern and signal intensities. The most significant peptide/protein profiles were obtained with 10 mg ferulic acid (FA) in 1 mL ACN/0.1% TFA (7:3, v/v) used as matrix system. Mixing the spores with the matrix solution directly on the MALDI target (dried‐droplet technique) resulted in an evenly distributed spores/matrix crystal layer, yielding highly reproducible peptide/protein profiles from the spore surfaces. Numerous abundant ions throughout the investigated m/z range (m/z 1500–15 000) could be detected. Differences in the obtained mass spectral patterns allowed the differentiation of spores of various Fusarium species. Copyright © 2009 John Wiley & Sons, Ltd.
Trauma Pod: a semi‐automated telerobotic surgical system
Authors: Garcia Pablo , Rosen Jacob , Kapoor Chetan , Noakes Mark , Elbert Greg , Treat Michael , Ganous Tim , Hanson Matt , Manak Joe , Hasser Chris , Rohler David , Satava Richard 
Published: February 2009

AbstractBackgroundThe Trauma Pod (TP) vision is to develop a rapidly deployable robotic system to perform critical acute stabilization and/or surgical procedures, autonomously or in a teleoperative mode, on wounded soldiers in the battlefield who might otherwise die before treatment in a combat hospital could be provided.MethodsIn the first phase of a project pursuing this vision, a robotic TP system was developed and its capability demonstrated by performing selected surgical procedures on a patient phantom.ResultsThe system demonstrates the feasibility of performing acute stabilization procedures with the patient being the only human in the surgical cell. The teleoperated surgical robot is supported by autonomous robotic arms and subsystems that carry out scrub‐nurse and circulating‐nurse functions. Tool change and supply delivery are performed automatically and at least as fast as performed manually by nurses. Tracking and counting of the supplies is performed automatically. The TP system also includes a tomographic X‐ray facility for patient diagnosis and two‐dimensional (2D) fluoroscopic data to support interventions. The vast amount of clinical protocols generated in the TP system are recorded automatically.ConclusionsAutomation and teleoperation capabilities form the basis for a more comprehensive acute diagnostic and management platform that will provide life‐saving care in environments where surgical personnel are not present. Copyright © 2009 John Wiley & Sons, Ltd.
Electroluminescent Characteristics of DBPPV–ZnO Nanocomposite Polymer Light Emitting Devices
Authors: Madhava Rao MV , Su YanKuin , Huang TsungSyun , Yeh Chen-Han , Tu Ming-Lung 
Published: February 2009

Abstract
We have demonstrated that fabrication and characterization of nanocomposite polymer light emitting devices with metal Zinc Oxide (ZnO) nanoparticles and 2,3-dibutoxy-1,4-poly(phenylenevinylene) (DBPPV). The current and luminance characteristics of devices with ZnO nanoparticles are much better than those of device with pure DBPPV. Optimized maximum luminance efficiencies of DBPPV–ZnO (3:1 wt%) before annealing (1.78 cd/A) and after annealing (2.45 cd/A) having a brightness 643 and 776 cd/m2at a current density of 36.16 and 31.67 mA/cm2are observed, respectively. Current density–voltage and brightness–voltage characteristics indicate that addition of ZnO nanoparticles can facilitate electrical injection and charge transport. The thermal annealing is thought to result in the formation of an interfacial layer between emissive polymer film and cathode.
CdSe Ring- and Tribulus-Shaped Nanocrystals: Controlled Synthesis, Growth Mechanism, and Photoluminescence Properties
Authors: Hu Pengfei , Jia Dianzeng , Cao Yali , Huang Yudai , Liu Lang , Luo Jianmin 
Published: February 2009

Abstract
With air-stable and generic reagents, CdSe nanocrystals with tunable morphologies were prepared by controlling the temperature in the solution reaction route. Thereinto, the lower reaction temperature facilitates the anisotropic growth of crystals to obtain high-yield CdSe ring- and tribulus-shaped nanocrystals with many branches on their surfaces. The photoluminescence properties are sensitive to the nature of particle and its surface. The products synthesized at room temperature, whose surfaces have many branches, show higher blue shift and narrower emission linewidths (FWHM) of photoluminescence than that of samples prepared at higher temperature, whose surfaces have no branches. Microstructural studies revealed that the products formed through self-assembly of primary crystallites. Nanorings formed through the nonlinear attachment of primary crystallites, and the branches on the surfaces grew by linear attachment at room temperature. And the structure of tribulus-shaped nanoparticle was realized via two steps of aggregation, i.e., random and linear oriented aggregation. Along with the elevation of temperature, the branches on nanocrystal surfaces shortened gradually because of the weakened linear attachment.
Effect of β‐Cyclodextrin on trans Fats, CLA, PUFA and Phospholipids of Milk Fat
Authors: Alonso L. , Cuesta P. , Gilliland S. E. 
Published: February 2009

AbstractThe aim of this study was to evaluate the effect of β‐cyclodextrin (β‐CD) on trans C18:1 fatty acid isomers, conjugated linoleic acid (CLA), polyunsaturated fatty acids (PUFA) and phospholipids in pasteurized milk. The individual trans C18:1 isomers were not significantly affected by the β‐CD. trans‐11 C18:1 (vaccenic acid) was found to be the major isomer (1.31 ± 0.12%) followed by trans‐15 C18:1 (0.35 ± 0.06%). Individual trans linoleic acids did not show differences from the effect of β‐CD, representing the high amount of the isomer trans‐11 cis‐15 C18:2 (0.433 ± 0.087%). The main CLA isomer cis‐9 trans‐11 C18:2 (rumenic acid) did not show differences between the control milk (0.672 ± 0.080%) and β‐CD milk (0.663 ± 0.074%). PUFA and omega‐3 and ‐6 fatty acids were not also significant by the effect of β‐CD. Total phospholipids were not significantly affected by effect of the β‐CD (0.023 ± 0.001% vs. 0.022 ± 0.001%). β‐CD is a effective oligosaccharide for cholesterol removal from pasteurized milk and does not significantly affect the lipid components of the milk fat.
Assessment of fertility by sperm mechanical energy using computer‐assisted sperm analysis system
Authors: Isobe Tetsuya 
Published: February 2009

AbstractPurposeIt is known that the energy distribution of sperm obeys the following equations and the total mechanical energy in a sperm population is expressed as nKλ × a constant. nKλ/102 is defined as the sperm energy index (SEI).
urn:x-wiley:14470578:rmb20004:equation:rmb20004-math-0001Here, P is the existing probability density of sperm, t is the square of amplitude of lateral head displacement, λ is the mean of t, n is the number of motile sperm in semen in a measurement field, and K is a constant determined for each semen sample. These values can be obtained with the use of computer‐assisted sperm analysis (CASA).MethodsSperm motility parameters were measured using CASA in 163 ejaculated semen samples from 47 infertile men (infertility group), and 162 ejaculated semen samples from 45 fertile men (natural pregnancy group). Kλ is defined for the present investigation as the mean energy index (MEI). SEI and MEI were obtained according to the methods described in sperm energy theory.ResultsThere were no natural pregnancy subjects with SEI < 0.5. All subjects with MEI > 2.0 and SEI > 1.0 were in the natural pregnancy group.ConclusionsAn assessment of fertility was possible by using the sperm energy index.
Effect of relaxin and IGF‐I on the pre‐implantation development of Mongolian gerbil (Meriones unguiculatus) embryos in vitro
Authors: Yoshida Mayumi , Obata Ryuichiro , Tsujii Hirotada 
Published: February 2009

AbstractPurposeBoth relaxin and insulin‐like growth factor (IGF) are members of the insulin super family. This study aimed to investigate the effect of relaxin and IGF‐I on the pre‐implantation of Mongolian gerbil of blastocyst development in vitro.MethodsBlastocysts and eight‐cell stage embryos were collected from female gerbils. Eight‐cell embryos and blastocysts were cultured in mM16 medium supplemented with or without relaxin or IGF‐I for 24 h. Blastocysts were counted for total, inner cell mass (ICM) and trophectoderm (TE) cell numbers, and assessed apoptosis incidence. In addition, to measure incorporation of 3H‐methionine, blastocysts were cultured for 3 h with relaxin or IGF‐I, washed with trichloroacetic acid and measured by liquid scintiration counter.ResultsRelaxin (200 ng/ml) increased total, TE and ICM cell numbers of blastocyst (P < 0.05) when it was compared with the control. IGF‐I (150 ng/ml) also has influence on total and ICM cell numbers of blastocyst when compared with control. Apoptosis incidence was relatively low, and a significant difference was not observed between each group. The effect of relaxin on incorporation of 3H‐methionine was higher than the control group (P < 0.05). Relaxin increased the developmental rate from the eight‐cell stage to blastocyst (P < 0.05).ConclusionsIn conclusion, relaxin and IGF‐I stimulated protein synthesis and increased cell numbers of blastocysts, promoting development of the gerbil embryo in vitro culture.