bluuebunny/crossref_metadata_2025_split huggingface dataset:
Early type I interferon‐mediated signals on B cells specifically enhance antiviral humoral responses
Authors: Fink Katja , Lang Karl S. , Manjarrez‐Orduno Nataly , Junt Tobias , Senn Beatrice M. , Holdener Martin , Akira Shizuo , Zinkernagel Rolf M. , Hengartner Hans 
Published: June 2006

AbstractType I interferons (IFN‐I) limit viral spread by inducing antiviral genes in infected target cells and by shaping the adaptive response through induction of additional cytokines. Vesicular stomatitis virus (VSV) efficiently triggers the production of IFN‐I in mice, and it is suggested that IFN‐α is induced after binding of VSV to TLR7 in infected cells. Our study with virus‐specific B cell receptor‐transgenic mice demonstrates here that IFN‐I directly fuel early humoral immune responses in vivo. VSV‐specific B cells that lacked IFN‐α/β receptors were considerably impaired in plasma cell formation and in generating antiviral IgM. At low viral titers, production of IFN‐α following VSV infection was independent of TLR7‐mediated signals. Interestingly, however, TLR7 ligation in B cells increased the formation of early antiviral IgM. These findings indicate that IFN‐α‐mediated augmentation of specific B cell responses is a partially TLR7‐ and virus dose‐dependent mechanism.
New Domino Silyl Enol Ether Reactions in the Synthesis of a Tetrodecamycin Fragment
Authors: He Jing , Tchabanenko Kirill , Adlington Robert M. , Cowley Andrew R. , Baldwin Jack E. 
Published: June 2006

AbstractOn heating in toluene at 180 °C for four days the TMS enol ether 7 underwent a domino acid catalysed rearrangement, Diels–Alder cycloaddition and further rearrangement to give the bicyclic TMS enol ether 17, which was converted into a tetrodecamycin precursor 3 in three synthetic steps. Further, monocyclic silyl enol ethers were consecutively treated with mCPBA and bromine to give syn α‐hydroxy α′‐bromo ketones in a one‐pot reaction sequence. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
A Formal Total Synthesis of Salvadione
Authors: Maier Martin E. , Bayer Alexander 
Published: June 2006

AbstractThe tricyclic 6‐7‐6 core structure of the triterpene salvadione (1) was obtained in an efficient manner from the aryl bromide 16 and the alkyl iodide 35 carrying a methylenecyclohexane group at the terminus. Alkylation of the anion derived from 16 with the iodide 35 gave the tethered system 36. This compound was converted into the allylic bromide 40. Finally, a Lewis acid mediated intramolecular Friedel–Crafts alkylation furnished the target structure 13 in good overall yield. The synthesis of tricyclic compound 13 represents a formal total synthesis of salvadione (1). (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
Interdigitated Conductometric Immunosensor for Determination of Interleukin‐6 in Humans Based on Dendrimer G4 and Colloidal Gold Modified Composite Film
Authors: Liang Kezhong , Mu Weijun , Huang Meiying , Yu Zhongxue , Lai Qingke 
Published: June 2006

AbstractA highly sensitive, fast and stable conductometric immunosensor for determination of interleukin‐6 (IL6) in humans is developed by encapsulation of horseradish peroxidase‐labeled interleukin‐6 antibody (HRP‐anti‐IL6) in poly(amidoamine) fourth‐generation dendrimer (dendrimer) and colloidal gold (nanogold) modified composite architecture. The presences of nanogold and dendrimer provided a congenial microenvironment for the immobilized biomolecules and decreased the electron transfer impedance, leading to a direct electrochemical behavior of the immobilized HRP. The formation of the antibody‐antigen complex by a simple one‐step immunoreaction between the immobilized HRP‐anti‐IL6 and IL6 in sample solution introduced a barrier of direct electrical communication between the immobilized HRP and the gold electrode surface, thus local conductivity variations could be detected by the HRP electrocatalytic reaction in 0.02 M phosphate buffer solution (pH 7.0) containing 50 μM H2O2, 0.01 M KI and 0.15 M NaC1. Under optimal conditions, the proposed immunosensor exhibited a good conductometric response to IL6 in a linear range from 30 to 300 pg/mL with a relatively low detection limit of 10 pg/mL at 3δ. The precision and reproducibility are acceptable with the intra‐assay CV of 7.3% and 5.6% at 100 and 200 pg/mL IL6, respectively. The storage stability of the proposed immunosensor is acceptable in a pH 7.0 PBS at 4 °C for 8 days. Importantly, the proposed methodology could be extended to the detection of other antigens or biocompounds.
Electrochemical Studies of Oxidation of Lomefloxacin and Interaction with Calf Thymus DNA at Nano‐SnO2/DHP Modified Electrode
Authors: Zhang Yuzhong , Cai Yuejuan , Su Shao , Ni Yonghong 
Published: June 2006

AbstractA nanoparticle thin film modified electrode has been constructed using a glassy carbon electrode (GCE) coated with a nano‐tin oxide/dihexadecylphosphate (nano‐SnO2/DHP). In pH 6.0 phosphate buffer solutions (PBS), lomefloxacin (LMF) appeared as an anodic peak with peak potential of 1.35 V at nano‐SnO2/DHP modified electrode. In comparison with a bare GCE or a nano‐SnO2 modified electrode, the nano‐SnO2/DHP modified electrode exhibited an enhanced effectiveness for the oxidation of LMF. Cyclic voltammetry (CVs) coupled with fluorescence and UV/vis absorbance spectra techniques were used to study the interaction of LMF with Calf thymus DNA (ctDNA) in phosphate buffer solutions (PBS). The interaction of LMF and ctDNA could result in a considerable decrease in the peak currents and positive shift in the peak potential, as well as changes of fluorescence, UV/vis adsorption spectra and gel electrophoresis. All the acquired data showed that the new adduct between LMF and ctDNA was formed. Electrochemistry coupled with spectroscopy techniques could provide a relatively easy way to obtain useful information about the molecular mechanism of LMF‐ctDNA interactions.
A new approach for the removal of protein impurities from purified biologicals using combinatorial solid‐phase ligand libraries
Authors: Fortis Frederic , Guerrier Luc , Righetti Pier Giorgio , Antonioli Paolo , Boschetti Egisto 
Published: June 2006

AbstractThe removal of last impurity traces from a purified protein is generally called polishing. It is an important step in downstream processing since protein impurities may generate undesirable side effects when the preparation is intended for research, diagnostic and more importantly therapeutic applications. Polishing is generally achieved by using orthogonal separation methods to previous steps, the most common being gel permeation chromatography. In spite of its polishing effectiveness, this technique suffers from a poor separation capacity and modest productivity as a result of low speed. Other approaches, for instance, based on anion exchange or on hydrophobic chromatography, that may be optimized for a given process cannot be used as generic methods. This document reports for the first time the use of a combinatorial solid‐phase peptide library as a general method for the removal of impurity traces. Several examples of impurity trace removal are reported; starting material is either a pure protein spiked with serum proteins or with Escherichia coli extracts or current purified proteins still containing a small percentage of impurities. Among polished proteins are recombinant human albumin expressed in Pichia pastoris and human transferrin purified from whole plasma. This new method is used in neutral or even physiological pH and ionic strength conditions, with a remarkable capability to remove impurities. The process is as rapid as current adsorption chromatography procedures usable for the removal of a large number of protein impurities, with each one present in small amounts, such as host cell proteins.
Studying protein‐drug interaction by microfluidic chip affinity capillary electrophoresis with indirect laser‐induced fluorescence detection
Authors: Liu Xiaojun , Liu Xin , Liang Aiye , Shen Zheng , Zhang Yu , Dai Zhongpeng , Xiong Bohui , Lin Bingcheng 
Published: June 2006

AbstractWe developed a microfluidic chip‐affinity CE method based on indirect LIF detection to study protein‐drug interactions. The interaction between heparin and BSA was quantitatively studied, as a model system. In our method, sodium fluorescein was chosen as background, and redistilled water as marker to monitor EOF. The electrophoretic mobility changes of BSA were measured, with various concentrations of heparin added to the running buffer. Each run was completed within 80 s. The binding constant was determined to be (1.24 ± 0.05)×103 M−1, which was in good agreement with that reported in the literature.
Bioanalysis in structured microfluidic systems
Authors: Ros Alexandra , Hellmich Wibke , Regtmeier Jan , Duong Thanh Tu , Anselmetti Dario 
Published: June 2006

AbstractMicrofluidic and lab‐on‐a‐chip devices have attracted widespread interest in separation sciences and bioanalysis. Recent designs in microfluidic devices extend common separation concepts by exploiting new phenomena for molecular dynamics on a length scale of 10 μm and below, giving rise to novel manipulation tools and nonintuitive phenomena for microseparations. Here, we focus on three very recent developments for bioseparations based on tailored microfluidic systems: Single cell navigation, trapping and steering with subsequent on‐chip lysis, protein separation and LIF detection (Section 3.1), then we report dielectrophoretic trapping and separation of large DNA fragments in structured microfluidic devices (Section 3.2). Finally, a paradoxial migration phenomenon based on thermal fluctuations, periodically arranged microchannels and a biased alternating current electric field is presented in Section 3.3.
Capillary electrophoresis‐mass spectrometry, an attractive tool for drug bioanalysis and biomarker discovery
Authors: Servais Anne‐Catherine , Crommen Jacques , Fillet Marianne 
Published: June 2006

AbstractThe coupling of CE with MS detection, a relatively recent hyphenated technique, has gained increasing respect in the field of bioanalytical applications over the past few years. The first part of this review presents CE‐MS applications dealing with drug bioanalysis, including forensic analysis and metabolism studies. Practical considerations to achieve a robust and sensitive CE‐MS coupling are also presented. It is indeed essential to strictly control some critical electrospray parameters, such as the sheath liquid composition and flow rate, the nebulizing gas pressure as well as the capillary outlet position. The second part of the review critically describes the applications of CE coupled on‐line to MS for the identification of biomarkers in body fluids for diagnostic purposes. Since the sample preparation procedures strongly differ according to the intended use (drug bioanalysis or biomarker discovery), they are discussed separately, taking into account the particular properties of plasma and urine matrices.
Glycosylation patterns of human chorionic gonadotropin revealed by liquid chromatography‐mass spectrometry and bioinformatics
Authors: Toll Hansjörg , Berger Peter , Hofmann Andreas , Hildebrandt Andreas , Oberacher Herbert , Lenhof Hans Peter , Huber Christian G. 
Published: June 2006

AbstractDue to their extensive structural heterogeneity, the elucidation of glycosylation patterns in glycoproteins such as the subunits of human chorionic gonadotropin (hCG), hCG‐α, and hCG‐β, remains one of the most challenging problems in the proteomic analysis of post‐translational modifications. In consequence, glycosylation is usually studied after decomposition of the intact proteins to the proteolytic peptide level. However, by this approach all information about the combination of the different glycopeptides in the intact protein is lost. In this study we have, therefore, attempted to combine the results of glycan identification after tryptic digestion with molecular mass measurements on the native starting material of the new first WHO Reference Reagents (RR) for hCG‐α (99/720) and hCG‐β (99/650). Despite the extremely high number of possible combinations of the glycans identified in the tryptic peptides by HPLC‐MS (>1000 for hCG‐α and >10 000 for hCG‐β), the mass spectra of intact hCG‐α and hCG‐β revealed only a limited number of glycoforms present in hCG preparations from pools of pregnancy urines. Peak annotations for hCG‐α were performed with the help of a bioinformatic algorithm that generated a database containing all possible modifications of the proteins, including modifications possibly introduced during sample preparation such as oxidation or truncation, for subsequent searches for combinations fitting the mass difference between the polypeptide backbone and the measured molecular masses. Fourteen different glycoforms of hCG‐α, containing biantennary, partly sialylized hybrid‐type glycans, including methionine‐oxidized and N‐terminally truncated forms, were identified. Mass spectra of high quality were also obtained for hCG‐β, however, a database search mass accuracy of ±5 Da was insufficient to unambiguously assign the possible combinations of post‐translational modifications. In summary, mass spectrometric fingerprints of intact molecules were shown to be highly useful for the characterization of glycosylation patterns of different hCG preparations such as the new first WHO RR for immunoassays and could be the first step in establishing biophysical reference methods for hCG and related molecules.
Glycoform characterization of erythropoietin combining glycan and intact protein analysis by capillary electrophoresis – electrospray – time‐of‐flight mass spectrometry
Authors: Balaguer Elvira , Demelbauer Uwe , Pelzing Matthias , Sanz‐Nebot Victoria , Barbosa José , Neusüß Christian 
Published: June 2006

AbstractGlycosylation of recombinant human erythropoietin (rHuEPO) is a post‐translational process that alters biological activity, solubility and lifetime of the glycoprotein in blood, and strongly depends on the type of cell and the cell culture conditions. A fast and simple method providing extensive carbohydrate information about the glycans present in rHuEPO and other glycoproteins is needed in order to improve current methods in drug development or product quality control. Here, an improved method for intact rHuEPO glycoform characterization by CZE‐ESI‐TOF MS has been developed using a novel capillary coating and compared to a previous study. Both methods allow a fast separation in combination with accurate mass characterization of the single protein isoforms. The novel dynamic coating provides a separation at an EOF close to zero, enabling better separation. This results in an improved mass spectrometric resolution and the detection of minor isoforms. In order to assign an unequivocal carbohydrate composition to every intact glycoform, a CZE‐ESI‐MS separation method for enzymatically released underivatized N‐glycans has been developed. The TOF MS allows the correct identification of the glycans due to its high mass accuracy and resolution. Therefore, glycan modifications such as acetylation, oxidation, sulfation and even the exchange of OH by NH2 are successfully characterized. Information of the protein‐backbone molecular mass has been combined with results from peptide analysis (revealing information about O‐glycosylation) and from the glycan analysis, including the detection of as yet undescribed glycans containing four antennae and five sialic acids. This allows an unequivocal assignment of an overall glycosylation composition to the molecular masses obtained for the intact rHuEPO glycoforms.
Dating of erosion surface and terraces in the eastern Qilian Shan, northwest China
Authors: Pan Baotian , Gao Hongshan , Wu Guangjian , Li Jijun , Li Bingyuan , Ye Yuguang 
Published: June 2006

AbstractThe actively deformed foreland of eastern Qilian Shan (mountains) contains well‐preserved geomorphic features such as erosion surfaces, river terraces and tectonically uplifted alluvial fans, providing suitable archives for research on regional tectonic activities and palaeoclimatic changes. These geomorphic surfaces are well dated by using a combination of magnetostratigraphy, electron spin resonance, thermoluminescence, infra‐red stimulated luminescence, radiocarbon dating, and correlation with the well‐established loess–palaeosol sequences of China. Our results show that the erosion surface formed about 1·4 Ma ago, and the age of river terraces is 1·24 Ma, 820–860 ka, 780 ka, 420–440 ka, 230–250 ka, 140 ka, 60 ka and 10 ka, respectively. Valley incision rates of c. 0·09–0·25 m ka−1 have been identified. The repetitive stratigraphic and geomorphic pattern of these terraces indicates the fluvial sedimentation–incision cycles are tightly associated with the 100‐ka glacial–interglacial climatic cycles. Copyright © 2006 John Wiley & Sons, Ltd.
Rat choroid plexuses contain myeloid progenitors capable of differentiation toward macrophage or dendritic cell phenotypes
Authors: Nataf Serge , Strazielle Nathalie , Hatterer Eric , Mouchiroud Guy , Belin Marie‐Françoise , Ghersi‐Egea Jean‐François 
Published: June 2006

AbstractThe interface between the blood and the cerebrospinal fluid (CSF) is formed by the choroid plexuses (CPs), which are specialized structures located within the brain ventricles. They are composed of a vascularized stroma surrounded by a tight epithelium that controls molecular and cellular traffic between the blood and the CSF. Cells expressing myeloid markers are present within the choroidal stroma. However, the exact identity, maturation state, and functions of these CP‐associated myeloid cells are not fully clarified. We show here that this cell population contains immature myeloid progenitors displaying a high proliferative potential. Thus, in neonate rats and, to a lesser extent, in adult rats, cultured CP stroma cells form large colonies of macrophages, in response to M‐CSF or GM‐CSF, while, under the same conditions, peripheral blood monocytes do not. In addition, under GM‐CSF treatment, free‐floating colonies of CD11c+ monocytic cells are generated which, when restimulated with GM‐CSF and IL‐4, differentiate into OX62+/MHC class II+ dendritic cells. Interestingly, in CP stroma cultures, myeloid cells are found in close association with fibroblastic‐like cells expressing the neural stem‐cell marker nestin. Similarly, in the developing brain, macrophages and nestin+ fibroblastic cells accumulate in vivo within the choroidal stroma. Taken together, these results suggest that the CP stroma represents a niche for myeloid progenitors and may serve as a reservoir for brain macrophages. © 2006 Wiley‐Liss, Inc.
Different expression of synemin isoforms in glia and neurons during nervous system development
Authors: Izmiryan A. , Cheraud Y. , Khanamiryan L. , Leterrier J. F. , Federici T. , Peltekian E. , Moura‐Neto V. , Paulin D. , Li Z. , Xue Z. G. 
Published: June 2006

AbstractThe synemin gene encodes proteins belonging to the intermediate filament family. These proteins confer resistance to mechanical stress and modulate cell shape. Three synemin isoforms, of 180 (H), 150 (M) and 41 (L) kDa, are produced by alternative splicing of the pre‐mRNA and are regulated differently during development. The three isoforms differ in their C‐terminal tail domains, while their IF rod domains are identical. Synemins H/M occurred together with nestin and vimentin in glial progenitors during the early differentiation of the developing mouse central nervous system. They are later found in GFAP‐labeled cells. In contrast, the L isoform appeared only in neurons, together with neurofilaments and βIII‐tubulin in the brain after birth. However, synemin L appeared from E13 in the peripheral nervous system, where it was confined to the neurons of spinal ganglia. In the meantime, the synemin H/M isoforms were found in both the neurons and Schwann cells of the sensorial ganglia from E11. Tissue fractionation and purification of IFs from adult mouse spinal cord revealed that the synemin L isoform binds to neurofilaments associated with the membrane compartment. This report describes the synthesis of the three synemin isoforms by selective cell types, and their temporal and spatial distributions. Mechanisms specific to neurons and glia probably control the splicing of the common synemin mRNA and the synthesis of each synemin isoform. © 2006 Wiley‐Liss, Inc.
Water saving irrigation in China
Authors: Li Yuanhua 
Published: June 2006

AbstractPer capita freshwater availability in China is among the lowest in the world and increasingly in short supply. Less water will be available for irrigation, which consumes the largest amount of fresh water because of the rapidly increased demands for fresh water for industrial and domestic use. To feed the increasing population under the conditions of keeping sound ecosystems and environment, there is an urgent need for China to produce more food with less water than for many other countries in the world. In recent decades China has pioneered some water saving policies and water saving irrigation (WSI) techniques, aimed at increasing water and land productivity. Policies for WSI from high level support conducive institutional development, leading to maximization of the effects of agricultural infrastructure, and of successful research on, and dissemination of, new technologies. There are many success stories about “real” water savings in China. This paper introduces the development of the WSI techniques and the impacts of WSI on society, the economy and the environment, and presents the experiences and lessons on WSI from China. Based on the analysis on the supply and demand of fresh water, the objectives and tasks for water saving from irrigated agriculture in China are discussed, and the strategies for sustainable water use and agricultural development and the main measures leading to increasing water and land productivity are mentioned. Copyright © 2006 John Wiley & Sons, Ltd.
Overview of Dujiangyan Irrigation Scheme of ancient China with current theory
Authors: Li Keke , Xu Zhifang 
Published: June 2006

AbstractThe Dujiangyan Irrigation Scheme is located in the middle reach of the Mingjiang River in Sichuan Province. It was initiated by Li Bing, the governor of Shu Prefecture, in the Qin Dynasty in 256 BC. It is a great scheme with a long history of 2260 years in ancient China, and has been very well operated until today.The headworks of the Dujiangyan Irrigation Scheme are composed of three major parts, i.e. Dujiang Yuzui (fish mouth), Feishayan, and Baopingkou. Dujiang Yuzui is a diversion dam, dividing the Mingjiang River water into two rivers, the Outer River and the Inner River. Feishayan is a spillway used for removing sand and excess water from the Inner River into the Outer River during flood. Baopingkou is an intake of the irrigation system, which automatically controls for a steady flow. These three parts are combined as an organic and complete whole with multiple functions of diverting water, spilling flood, releasing sediment, silt sedimentation, and automatic control of irrigation water. The whole headworks are reasonably planned and ingeniously coordinated with obvious effectiveness. In particular, this scheme has successfully treated the silt problem, therefore the possibility of being damaged by silt sedimentation is to a great extent avoided, and thus it can continue to flourish. In addition, the system of yearly maintenance also has its specialty: the construction technique is easily mastered by farmers, and all the construction materials came from local places. Therefore, the Dujiangyan Irrigation Scheme can normally be operated generation after generation. The Dujiangyan Irrigation Scheme encapsulates the scientific intelligence and civilization of Chinese nationality, and it still plays a vital role in the economic, social, ecological and environmental benefits for Sichun Province nowadays. It is a model of harmonious coexistence between mankind and nature, and is also included as a World Heritage Site by the United Nations Educational, Scientific and Cultural Organization (UNESCO) as the first water project in the world. Copyright © 2006 John Wiley & Sons, Ltd.