bluuebunny/crossref_metadata_2025_split huggingface dataset:
Five New Iridoids from Patrinia rupestris
Authors: Yang Xiu‐Ping , Li Er‐Wei , Zhang Qi , Yuan Cheng‐Shan , Jia Zhong‐Jian 
Published: July 2006

AbstractFive new iridoids, namely rupesin A–E (1–5, resp.), together with six known iridoids, 6–11, were isolated from the roots of Patrinia rupestris. Their structures were elucidated by spectroscopic methods including IR, UV, MS, and 1D‐ and 2D‐NMR experiments, and comparison with data of known analogues. Compounds 4 and 11, compounds 1, 2, 5, 6, 8, 9, and 10, and compounds 3, 4, and 8 showed significant antibacterial activities against Bacillus subtilis, Escherichia coli, and Staphylococcus aureus, respectively.
Four New Compounds from the Leaves of Acer truncatum
Authors: Dong Lang‐Ping , Liu Hai‐Yang , Ni Wei , Li Jun‐Zhu , Chen Chang‐Xiang 
Published: July 2006

AbstractFour new compounds, 3‐(4‐hydroxy‐3,5‐dimethoxyphenyl)propyl formate (1), 2,6‐dimethoxy‐4‐[(1S)‐3‐methoxypropyl]phenol (2), (1R,2R)‐4‐[(3R)‐3‐hydroxybutyl]‐3,3,5‐trimethylcyclohex‐4‐ene‐1,2‐diol (3), and (1S,3R,3aR,6S,7S,9aR)‐decahydro‐1‐(hydroxymethyl)‐1,7‐dimethyl‐3a,7‐methano‐3aH‐cyclopentacyclooctene (4) were isolated from the leaves of Acer truncatum, together with twelve known compounds. Their structures were elucidated on the basis of extensive spectroscopic techniques. The absolute configuration of compound 3 was established by the modified Mosher's method. All compounds were evaluated for antibacterial activities.
Cytotoxic Sulfated Triterpene Glycosides from the Sea Cucumber Pseudocolochirus violaceus
Authors: Zhang Shu‐Yu , Yi Yang‐Hua , Tang Hai‐Feng 
Published: July 2006

AbstractBioassay‐guided fractionation of the active BuOH extract of the sea cucumber Pseudocolochirus violaceus resulted in the isolation of three new sulfated triterpene glycosides, i.e., violaceusides I, II, and III (1–3, resp.), as active compounds causing morphological abnormality of Pyricularia oryzae mycelia. Their structures were elucidated by spectroscopic methods including 2D‐NMR and MS experiments, as well as chemical evidence. Compounds 1–3 exhibit the same structural features, i.e., the presence of a 16‐oxo group in the holostane‐type triterpene aglycone with the C(7)C(8) bond, but differ in the side chains and the tetrasaccharide moieties. Compound 1 possesses one sulfate group, while 2 and 3 are disulfated glycosides. All the glycosides showed significant in vitro cytotoxicities against human gastric cancer MKN‐45 and human colon cancer HCT‐116 cells.
Synthesis, Structure and Magnetic properties of Chiral and Nonchiral Transition‐Metal Malates
Authors: Beghidja Adel , Rabu Pierre , Rogez Guillaume , Welter Richard 
Published: July 2006

AbstractCarboxylate‐bridged complexes of transition metals, MII=MnII, FeII, CoII, NiII, ZnII, were synthesised by reaction of MII salts with dl‐malate and L‐malate under hydrothermal conditions. These complexes form four series of compounds, which have been fully characterised structurally, thermally and magnetically. The crystal structures of the new chiral compounds, [Mn(L‐mal)(H2O)] (1), [Fe(L‐mal)(H2O)] (2), [Co(L‐mal)(H2O)] (3) and [Zn(L‐mal)(H2O)] (4) as well as those of the bimetallic analogues [Mn0.63Co0.37(L‐mal)(H2O)] (5) and [Mn0.79Ni0.21(L‐mal)(H2O)] (6) have been solved by single‐crystal X‐ray diffraction. The six L‐malate monohydrates crystallise in the chiral space group P212121 and consist in a three‐dimensional network of metal(II) centres in octahedral sites formed by oxygen atoms. These structures were compared to those of the chiral trihydrate compounds [Co(L‐mal)(H2O)]⋅2 H2O (7), [Ni(L‐mal)(H2O)]⋅2 H2O (8) and [Co0.52Ni0.48(L‐mal)(H2O)]⋅2 H2O (9), which exhibit helical chains of MII centres, and those of dl‐malate dihydrates [Co(dl‐mal)(H2O)]⋅H2O (10) and [Ni(dl‐mal)(H2O)⋅H2O (11) and trihydrate [Mn(L‐mal)(H2O)]⋅2 H2O (12) highlighting the great flexibility of the coordination by the malate ligand. UV/Vis spectroscopic results are consistent with octahedral coordination geometry of high‐spin transition‐metal centres. Extensive magnetic characterisation of each homologous series indicates rather weak coupling interaction between paramagnetic centres linked through carboxylate bridges. Curie‐like paramagnetic, antiferromagnetic, ferromagnetic or weak ferromagnetic behaviour is observed and discussed on the basis of the structural features. The bimetallic compounds 5 and 6 represent new examples of chiral magnets.
Highly Selective Recognition of Adenine Nucleobases by Synthetic Hosts with a Linked Five‐Six‐Five‐Membered Triheteroaromatic Structure and the Application to Potentiometric Sensing of the Adenine Nucleotide
Authors: Hisamatsu Yosuke , Hasada Keiko , Amano Fumi , Tsubota Yasuhiro , Wasada‐Tsutsui Yuko , Shirai Naohiro , Ikeda Shin‐ichi , Odashima Kazunori 
Published: July 2006

AbstractA new structure for an adenine‐selective host molecule, featuring the pertinent link of five‐six‐five‐membered heteroaromatic rings and two carbamoyl NH sites, was developed. This structure provides a correctly oriented array of complementary hydrogen bonding sites for the adenine nucleobase, which exploits both Watson–Crick and Hoogsteen‐type interactions. The complexation with adenine nucleobases by multiple hydrogen bonding was supported by 1H NMR spectroscopy. This type of host displayed high selectivity in complexation, with an accompanying fluorescent response to lipophilized adenosine in CHCl3. Furthermore, a remarkably selective potentiometric response was attained for adenosine 5′‐monophosphate over 5′‐GMP, 5′‐CMP, and 5′‐UMP by using an ion‐selective electrode with a PVC‐supported solvent polymeric membrane. This indicates recognition of water‐soluble nucleotide guests through the membrane–water interface. These findings are expected to form a reliable basis for the development of artificial sensing systems for mononucleotides in biological systems.
Electrochemically Degraded Dopamine Film for the Determination of Dopamine
Authors: Chang Hye‐Young , Kim Dong Il , Park Yu Chul 
Published: July 2006

AbstractA dopamine (DA) polymer was deposited electrochemically on to a glassy carbon (GC) surface until the electrode surface was passivated. The DA film on the GC surface was re‐formed for high sensitivity and reproducibility by electrochemical degradation. The re‐formed electrode was sensitive and selective in the determination of DA in the presence of ascorbic acid. The linear range obtained by square‐wave voltammetry was between 0.1 and 2.1 μM (R=0.996, n=6) with a sensitivity of 1.2 μA μM−1 and a detection limit (S/N=3) of 0.04 μM. The electropolymerized DA film was stable and the re‐formed electrode was reproducible for DA determination.
A Novel Al(III)‐Selective Electrochemical Sensor Based on N,N′‐Bis(salicylidene)‐1,2‐phenylenediamine Complexes
Authors: Gholivand M. B. , Ahmadi F. , Rafiee E. 
Published: July 2006

AbstractA polyvinylchloride membrane sensor based on N,N′‐bis(salecylidene)‐1,2‐phenylenediamine (salophen) as membrane carrier was prepared and investigated as a Al3+‐selective electrode. The sensor exhibits a Nernstian response toward Al(III) over a wide concentration range (8.0×10−7–3.0×10−2 M), with a detection limit of 6.0×10−7 M. The potentiometric response of the sensor is independent of the pH of the test solution in the pH range 3.2–4.5. The electrode possesses advantages of very fast response and high selectivity for Al3+ in comparison with alkali, alkaline earth and some heavy metal ions. The sensor was used as an indicator electrode, in the potentiometric titration of aluminum ion and in determination of Al3+ contents in drug, water and waste water samples.
Bioelectrochemical Magnetic Immunosensing of Trichloropyridinol: A Potential Insecticide Biomarker
Authors: Liu Guodong , Timchalk Charles , Lin Yuehe 
Published: July 2006

AbstractA fast, simple and sensitive bioelectrochemical magnetic immunosensing method is developed to monitor a potential insecticide biomarker, trichloropyridinol (TCP), in environmental sample. A magnet/glassy carbon (MGC) working electrode was used to accumulate immunocomplex associated magnetic beads and separate free and unbound reagents after liquid phase competitive immunoreaction among TCP antibody coated magnetic beads, TCP analyte and horseradish peroxidase (HRP) labeled TCP. The activity of HRP tracers was monitored by square‐wave voltammetry (SWV) by scanning electrocactive enzymatic product in the presence of 3,3′,5,5′‐tetramethylbenzidine dihydrochloride and hydrogen peroxide (TMB‐H2O2) substrate solution. The electrochemical signal of enzymatic product was greatly enhanced by dual accumulation events: magnetic accumulation of enzyme tracers bound magnetic beads and constant potential accumulation of enzymatic product. The voltammetric characteristics of substrate and enzymatic product were investigated, and the parameters of SWV analysis and immunoassay were optimized. Under the optimal conditions the immunosensor was used to measure as low as 5 ng L−1 (ppt) TCP, which is 50‐fold lower than the value indicated by the manufacture of the TCP RaPID Assay kit (0.25 μg/L, colorimetric detection). The performance of the developed immunosensing system was successfully evaluated with river water samples spiked with TCP, indicating this convenient and sensitive technique offers great promise for decentralized environmental application. This technique could be readily used for detection of other environmental contaminants by developing specific antibodies against the contaminants and are expected to open new opportunities for environmental monitoring and public health.
Redox Properties of Ferricyanide Ion on Layer‐by‐Layer Thin Film‐Coated Gold Electrodes; Effects of Type of Polycationic Components in the Film
Authors: Takita Ryoichi , Okamura Yukiko , Endo Yoshihiro , Anzai Jun‐ichi 
Published: July 2006

AbstractThe surface of a gold (Au) electrode was coated with layer‐by‐layer (LbL) thin films composed of poly(vinyl sulfate) (PVS) and different type of poly(amine)s including poly(allylamine) (PAH), poly(ethyleneimine) (PEI) and poly(diallyldimethylammonium chloride) (PDDA) and redox properties of ferricyanide ion ([Fe(CN)6]3−) on the LbL film‐coated Au electrodes were studied. The LbL film‐coated electrodes exhibited redox response to [Fe(CN)6]3− ion when the outermost surface of the LbL film was covered with the cationic poly(amine)s while virtually no response was observed on the LbL film‐coated electrodes whose outermost surface was covered with PVS due to an electrostatic repulsion between [Fe(CN)6]3− ion and the negatively‐charged PVS layer. The redox properties of [Fe(CN)6]3− ion on the LbL film‐coated electrodes significantly depended on the type of polycationic materials in the LbL film. The LbL film‐coated electrodes which had been immersed in the [Fe(CN)6]3− solution for 15 min exhibited redox response even in a [Fe(CN)6]3− ion‐free buffer solution, suggesting that [Fe(CN)6]3− ion is confined in the films. In the buffer solution, redox peaks were observed between +0.1 and 0.4 V depending on the type of polycations in the film. Thus, [Fe(CN)6]3− ion can be confined in the film and the redox potential is polycation‐dependent.
Tape Casting of Graphite Material: A New Electrochemical Sensor
Authors: Chicharro M. , Bermejo E. , Moreno M. , Sánchez A. , Zapardiel A. , Rubio‐Marcos F. , Villegas M. 
Published: July 2006

AbstractTape casting is a feasible method for preparing ceramic tapes with different electrical and magnetic properties for multilayer ceramic devices. This paper describes the tape casting process for the preparation of a new kind of self‐standing carbon electrodes (SSCE) using different ratios of graphite and the organic additives generally used in the non‐aqueous tape casting process.
Lyotropic Liquid Crystal Templating of Groups 11 and 12 Metal Films
Authors: Bender Florian , Mankelow Rowena K. , Hibbert D. Brynn , Gooding J. Justin 
Published: July 2006

AbstractLiquid crystal templating has been used to produce metal films with nanometer‐sized pores. While successful templating procedures have been reported for metals from some groups of elements (e.g., groups 9 and 10), no such reports are available for other groups. This work investigates liquid crystal templating procedures for metals from groups 11 and 12. TEM indicates that permanent mesoporous structures are obtained for templated cadmium while copper forms mesoporous structures only temporarily. Silver, gold and zinc could not be templated at all. Reasons for these observations are briefly discussed, underlining the importance of various factors influencing the templating process.
Dust deposition near an eroding source field
Authors: Hagen L. J. , Pelt S. Van , Zobeck T. M. , Retta A. 
Published: July 2006

AbstractDeposition of suspended dust near eroding source fields can have detrimental effects on vegetation, as well as on soil and water quality. This study was undertaken to quantify dust deposition within 200 m of a source field during wind erosion events. Erosion was measured with BSNE samplers on a small field of Amarillo fine sandy loam at field at Big Spring, TX. Suspension‐sized dust discharge averaged 33 ± 5 per cent of the total sediment discharge and ranged from 18·0 to 147·4 kg m−1 during eight selected storm events. Within 200 m of the source field boundary, dust collected in deposition samplers placed above a vegetated surface averaged 34 per cent of initial dust discharge. Predicted deposition, according to a line source model, was 43 per cent. Actual deposition was likely near that predicted, because of lateral diffusion of the dust and some under‐sampling by the disk samplers. Thus, the line source model seems useful in estimating both the pattern and quantity of deposition. About 30 per cent of the suspended dust was deposited within the initial 50 m of vegetated surface, but only about 12–15 per cent was deposited in the initial 10 m. Published in 2006 by John Wiley & Sons, Ltd.
Carabid Beetles (Coleoptera, Carabidae) as Indicatorsof Hydrological Site Conditions in Floodplain Grasslands
Authors: Gerisch Michael , Schanowski Arno , Figura Wolfgang , Gerken Bernd , Dziock Frank , Henle Klaus 
Published: July 2006

AbstractThe relationship of carabid beetle species occurrence patterns and environmental variables characterising the hydrological regime has been studied at the River Elbe in Central Germany. Both flood duration and groundwater depth had major influence on species assemblages as the ordination of study plots mainly followed a gradient along these two variables. The simultaneous ordination of the plots according to species occurrence and environmental parameters showed a highly significant joint structure with the first two axes of a co‐inertia analysis, explaining >98% of the variance. A total of 27 species out of 129 caught fulfilled criteria of fidelity and specificity to the plots of the five clusters revealed by their abiotic conditions and were sufficiently abundant to be suitable indicators for one or a combination of clusters of plots. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Protective effects of isothiocyanates towards N‐nitrosamine‐induced DNA damage in the single‐cell gel electrophoresis (SCGE)/HepG2 assay
Authors: Arranz Nuria , Haza Ana I. , García Almudena , Möller Lennart , Rafter Joseph , Morales Paloma 
Published: July 2006

AbstractThe aim of this study was to investigate the protective effect of isothiocyanates towards N‐nitrosamine‐induced DNA damage in the single‐cell gel electrophoresis (SCGE)/HepG2 assay. None of the isothiocyanates (ITCs) concentrations tested in the presence or absence of formamidopyrimidine‐DNA glycosylase (Fpg) caused DNA damage per se. Combined treatments of HepG2 cells with phenethyl isothiocyanate (PEITC), allyl isothiocyanate (AITC) or indol‐3‐carbinol (I3C) and N‐nitrosopyrrolidine (NPYR) or N‐nitrosodimethylamine (NDMA) reduced the genotoxic effects of the N‐nitrosamines in a dose‐dependent manner. The protective effect of the three ITCs tested was higher towards NPYR‐induced oxidative DNA damage than against NDMA. The greatest protective effect towards NPYR‐induced oxidative DNA damage was shown by I3C (1 µM, 79%) and by PEITC (1 µM, 67%) and I3C (1 µM, 61%) towards NDMA (in presence of Fpg enzyme). However, in absence of Fpg enzyme, AITC (1 µM, 72%) exerted the most drastic reduction towards NPYR‐induced oxidative DNA damage, and PEITC (1 µM, 55%) towards NDMA. Our results indicate that ITCs protect human‐derived cells against the DNA damaging effect of NPYR and NDMA, two carcinogenic compounds that occur in the environment. Copyright © 2006 John Wiley & Sons, Ltd.
Human osteoblast response to silicon‐substituted hydroxyapatite
Authors: Botelho C.M. , Brooks R.A. , Best S.M. , Lopes M.A. , Santos J.D. , Rushton N. , Bonfield W. 
Published: July 2006

AbstractHuman osteoblasts were cultured on hydroxyapatite (HA), 0.8 wt % silicon substituted hydroxyapatite (Si‐HA) and 1.5 wt % Si‐HA discs. The influence of these substrates on cell behaviour in vitro was assessed by measuring total protein in the cell lysate and the production of several phenotypic markers: collagen type I (COL I), alkaline phosphatase (ALP), osteocalcin (OC), and the formation of bone mineral. After 7 days, β‐glycerophosphate and physiological levels of hydrocortisone were added to the culture medium to stimulate cell differentiation and mineral production. There was a significantly higher production of ALP on 1.5 wt % Si‐HA at day 7 following which, the addition of hydrocortisone promoted the differentiation of cells on the other two substrates. Hydrocortisone addition also decreased the production of OC. During the period, when hydrocortisone was present, no significant difference in behavior was seen between cells on Si‐HA and HA; however, following removal of hydrocortisone, cells responded to 0.8 wt % Si‐HA with a significant increase in protein production. Using fluorescence microscopy, nodular structures labeled with tetracycline were observed on the surface of all substrates after 21 days. These structures were deposited on areas of high cell density but were not related to the presence or level of silicon in the substrate. These results indicate that human osteoblasts are affected by the presence of silicon in the HA substrate and that the timing of these effects may be dependent upon the level of silicon substitution. © 2006 Wiley Periodicals, Inc. J Biomed Mater Res, 2006
Natural and chemically induced oligomeric ribonucleases: structural study by immobilized metal ion affinity electrophoresis and their functional relationship
Authors: Anissimova Maria V. , Baek Won‐Ok , Varlamov Valery P. , Mrabet Nadir T. , Vijayalakshmi Mookambeswaran A. 
Published: July 2006

AbstractOligomerization can endow proteins with novel structural and catalytic properties. The native dimer of bovine seminal ribonucleases (BS‐RNase) binds, melts and catalyses the hydrolysis of double‐stranded ribonucleic acids 30‐fold better than its pancreatic homologue, the monomeric RNase A. Chemically induced oligomers of pancreatic RNase A are also found to show an increase in enzyme activity on double‐stranded poly(A).poly(U) (Libonati, M. Bertoldi, M. and Sorrentino, S. (1996) Biochem. J. 318, 287‐290) and, therefore, can be considered as potential immunosuppressive and cytotoxic agents. We report here a study on the relationship between surface histidine topography in oligomeric forms of these ribonucleases and their catalytic properties. Subtle changes in structure conformation of both BS‐RNase and oligomeric RNase A are shown to result in a modification of the affinity of these proteins toward the immobilized transition‐metal chelate, IDA‐Cu(II). Because, such conformational change has been shown to correlate with an improvement of the newly acquired biological activities upon oligomerization, we can conclude that surface histidines topography constitutes an exquisite probe for the study of protein structure/function relationship. Copyright © 2006 John Wiley & Sons, Ltd.
Problems with identifying the ‘8200‐year cold event’ in terrestrial records of the Atlantic seaboard: a case study from Dooagh, Achill Island, Ireland
Authors: Head Katie , Turney Chris S. M. , Pilcher Jon R. , Palmer J. G. , Baillie M. G. L. 
Published: July 2006

AbstractThe Northern Hemisphere cooling event 8200 years ago is believed to represent the last known major freshwater pulse into the North Atlantic as a result of the final collapse of the North American Laurentide ice sheet. This pulse of water is generally believed to have occurred independently of orbital variations and provides an analogue for predicted increases in high‐latitude precipitation and ice melt as a result of anthropogenically driven future climate change. The precise timing, duration and magnitude of this event, however, are uncertain, with suggestions that the 100‐yr meltwater cooling formed part of a longer‐term cold period in the early Holocene. Here we undertook a multiproxy, high‐resolution investigation of a peat sequence at Dooagh, Achill Island, on the west coast of Ireland, to determine whether the 8200‐year cold event impacted upon the terrestrial vegetation immediately ‘downwind’ of the proposed changes in the North Atlantic. We find clear evidence for an oscillation in the early Holocene using various measures of pollen, indicating a disruption in the vegetation leading to a grassland‐dominated landscape, most probably driven by changes in precipitation rather than temperature. Radiocarbon dating was extremely problematic, however, with bulk peat samples systematically too young for the North Atlantic event, suggesting significant contamination from downward root penetration. The sustained disruption to vegetation over hundreds of years at Dooagh indicates the landscape was impacted by a long‐term cooling event in the early Holocene, and not the single century length 8200‐year meltwater event proposed in many other records in the North Atlantic region. Copyright © 2006 John Wiley & Sons, Ltd.
Reduction of catechin, rutin, and quercetin levels by interaction with food‐related microorganisms in a resting state
Authors: LoCascio Riccardo G , Mills David A , Waterhouse Andrew L 
Published: July 2006

AbstractFlavonoids are plant secondary metabolites abundant in foods and beverages of plant origin. These compounds are free radical scavengers and their consumption is linked to reduced incidence of coronary heart disease. In this study, two wine‐related microorganisms and one probiotic bifidobacteria strain were examined for their ability to absorb and/or transform the common flavonoids: quercetin, rutin, and catechin. Flavonoid absorption and/or transformation was determined using a resting cell assay (RCA) combined with high‐performance liquid chromatographic detection of the flavonoid losses. RCAs with Pediococcus pentosaceus ATCC 25745, Saccharomyces cerevisiae ATCC 36026, and Bifidobacterium longum DJO10A resulted in losses of rutin and quercetin. Further analysis of cell pellets indicated that, unlike rutin and catechin, most of the quercetin present in the assay was transported/adsorbed only into metabolically active cells. In 24 h the net quercetin loss from the resting cells of P. pentosaceus, S. cerevisiae, and B. longum was 21.3%, 27.1%, and 63.4%, respectively. These results suggest that these microorganisms, which are frequently present or added to food products, can decrease the overall concentration of quercetin, either through absorption or transport into the cell. The implications for the overall bioavailability of quercetin in humans remain to be determined. Copyright © 2006 Society of Chemical Industry