bluuebunny/crossref_metadata_2025_split huggingface dataset:
DC contact with HIV‐1‐infected cells leads to high levels of Env‐mediated virion endocytosis coupled with enhanced HIV‐1 Ag presentation
Authors: Muratori Claudia , Bona Roberta , Ruggiero Eliana , D'Ettorre Gabriella , Vullo Vincenzo , Andreotti Mauro , Federico Maurizio 
Published: January 2009

AbstractIn HIV‐infected patients, DC are likely to interact with both cell‐free HIV and HIV‐infected cells. We were interested in investigating the mechanism of virus transmission occurring upon contact between HIV‐1‐infected cells and DC, as well as the consequences for HIV‐1 Ag‐presenting activity. By comparing mixed co‐cultures with trans‐well cultures, we observed that cell‐to‐cell contact strongly increased HIV‐1 Env‐mediated virion endocytosis in target DC. This endocytosis was independent of HIV‐1 tropism, de novo infection, HIV‐1 Env‐CD4‐dependent fusion, and immature DC activation/maturation. We also found that augmentation of HIV‐1 endocytosis was closely correlated with strong, Env‐dependent HIV‐1 Ag presentation by DC. Our results provide a better understanding of the mechanisms underlying the induction of the anti‐HIV adaptive immune response.
DC therapy induces long‐term NK reactivity to tumors via host DC
Authors: Shimizu Kanako , Fujii Shin‐ichiro 
Published: January 2009

AbstractWe vaccinated mice with DC loaded with or without invariant NKT‐cell ligand α‐galactosylceramide and evaluated long‐term resistance against tumor challenge. When mice had been given either DC or DC/galactosylceramide and were challenged with tumor cells even 6–12 months later, both NK and NKT cells were quickly activated to express CD69 and produce IFN‐γ. The NK cells could resist a challenge with several different tumors in vivo. The activated NK and NKT cells could be depleted with anti‐NK1.1 treatment. In spite of this, the activated cells recovered, indicating that tumor‐responsive NK and NKT cells were being generated continuously as a result of vaccination with DC and were not true memory cells. The NK and NKT antitumor response in DC‐vaccinated mice depended on CD4+ T cells, but neither CD8+T cells nor CD4+CD25+ regulatory T cells. However, both vaccine DC and host DC were required for the development of long‐term, tumor reactive innate immunity. These results indicate that DC therapy in mice induces long‐lasting innate NK‐ and NKT‐cell activation through a pathway that requires host DC and CD4+ T cells and that the continued generation of active NK cells resists the establishment of metastases in vivo.
PI3K limits TNF‐α production in CD16‐activated monocytes
Authors: Kramer Phillip R. , Winger Vanessa , Reuben Jayne 
Published: January 2009

AbstractIgG complexes bind to Fc receptor family members FcγRI (CD64), FcγRII (CD32) and FcγRIII (CD16), activating cell MAPK and PI3K resulting in increased cytokine production from particular leukocytes. The signaling molecules involved in cytokine production after cross‐linking CD16 have not been determined in monocytes. To address this question, TNF‐α, IL‐1β and IL‐6 were measured in activated monocytes after inhibiting MEK1/2, PI3K and glycogen synthase kinase‐β (GSK‐3β). The roles of GSK‐3β and NF‐κB were then determined using reporter assays and siRNA treatment. The data suggested that an MAPK pathway stimulated TNF‐α release but that active PI3K limited TNF‐α, IL‐1β and IL‐6 cytokine production after cross‐linking CD16. PI3K was also shown to limit nuclear translocation of NF‐κB. The limiting effect of PI3K on TNF‐α production from activated monocytes depended on the decrease of GSK‐3β activity, which significantly reduced the transactivation of NF‐κB. Moreover, the TNF‐α production induced by CD16 cross‐linking was reduced in monocytes after treatment with siRNA against NF‐κB, implying that this transcription factor functioned in TNF‐α production. The results suggest that CD16 cross‐linking activated PI3K and that active PI3K limited TNF‐α production by inhibiting GSK‐3β activity, that blocked the action of NF‐κB.
Molecular basis of CD4 repression by the Swi/Snf‐like BAF chromatin remodeling complex
Authors: Wan Mimi , Zhang Jianmin , Lai Dazhi , Jani Anant , Prestone‐Hurlburt Paula , Zhao Lulu , Ramachandran Aruna , Schnitzler Gavin R. , Chi Tian 
Published: January 2009

AbstractThe Brg1/Brm‐associated factor (BAF) chromatin remodeling complex directly binds the CD4 silencer and is essential for CD4 repression during T‐cell development, because deletion of the ATPase subunit Brg1 or a dominant negative mutant of BAF57 each impairs CD4 repression in early thymocytes. Paradoxically, BAF57 is dispensable for remodeling nucleosomes in vitro or for binding of the BAF complex to the CD4 silencer in vivo. Thus, it is unclear whether BAF57‐dependent CD4 repression involves chromatin remodeling and, if so, how the remodeling translates into CD4 repression. Here we show that nucleosomes at the CD4 silencer occupy multiple translational frames. BAF57 dominant negative mutant does not alter these frames, but reduces the accessibility of the entire silencer without affecting the flanking regions, concomitant with localized accumulation of linker histone H1 and eviction of Runx1, a key repressor of CD4 transcription that directly binds the CD4 silencer. Our data indicate that precise nucleosome positioning is not critical for the CD4 silencer function and that BAF57 participates in remodeling H1‐containing chromatin at the CD4 silencer, which enables Runx1 to access the silencer and repress CD4. In addition to BAF57, multiple other subunits in the BAF complex are also dispensable for chromatin remodelling in vitro. Our data suggest that these subunits could also help remodel chromatin at a step after the recruitment of the BAF complex to target genes.
Selective Crystallization of Dimeric vs. Monomeric Dimethyltin‐Containing Tungstoarsenates(III) and ‐antimonates(III) with the Guanidinium Cation
Authors: Reinoso Santiago , Dickman Michael H. , Kortz Ulrich 
Published: January 2009

AbstractThe use of guanidinium cations [C(NH2)3]+ as crystallizing agents allowed us to selectively isolate the dimeric [{(CH3)2Sn(H2O)}4{(CH3)2Sn}(B‐β‐XW9O33)2]8– (1, X = AsIII; 2, X = SbIII) polyanions from the reaction of (CH3)2SnCl2 with Na9[B‐α‐XW9O33] (3:1 ratio) in water at pH 3. This reaction is known to give the monomeric [{(CH3)2Sn(H2O)2}3(B‐β‐XW9O33)]3– polyanions as the major species. Polyanions 1 and 2 are composed of one octahedral trans‐(CH3)2SnO4 moiety that bridges two trilacunary [B‐β‐XW9O33]9– Keggin subunits further decorated by two structurally nonequivalent {(CH3)2Sn}2+ functionalities each: one distorted octahedral trans‐(CH3)2SnO4 linking moiety and one trigonal‐bipyramidal cis‐(CH3)2SnO3 pendant group. This results in a dimeric, centrosymmetric assembly where each [B‐β‐XW9O33]9– subunit is connected to three {(CH3)2Sn}2+ functionalities through two Sn–O(W) bonds. Polyanions 1 and 2 polymerize upon crystallization by forming intermolecular Sn–O–W bridges resulting in the isostructural hybrid materials [C(NH2)3]8[{(CH3)2Sn(H2O)}4{(CH3)2Sn}(B‐β‐XW9O33)2]·10H2O (1a, X = AsIII; 2a, X = SbIII). Compounds 1a and 2a were characterized in the solid state by elemental analysis, infrared spectroscopy, thermal analysis, and single‐crystal X‐ray diffraction. The crystal packing shows a 2D arrangement of the polyanions connected by the trans‐(CH3)2SnO4 linking moieties, resulting in corrugated hybrid layers parallel to the (101) plane with the cis‐(CH3)2SnO3 pendant groups acting as interlamellar spacers.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)
Synthesis, Crystal Structures and Redox Properties of Mixed‐Sandwich Complexes of Ruthenium(II) with Cyclopentadienyl and Tris(pyrazolyl)methane Ligands
Authors: Kuzu Istemi , Nied Dominik , Breher Frank 
Published: January 2009

AbstractNew mixed‐sandwich ruthenium(II) complexes have been prepared by treatment of either [RuCp(acn)3][PF6] or [RuCp*(acn)3][PF6] (Cp = η5‐cyclopentadienyl; Cp* = η5‐pentamethylcyclopentadienyl, acn = CH3CN) with tris(pyrazolyl)methane (HTpm) and tris(3,5‐dimethylpyrazolyl)methane (MeTpm), respectively. [RuCp(HTpm)][PF6] (1), [RuCp*(HTpm)][PF6] (2) and [RuCp(MeTpm)][PF6] (3) have been examined by single‐crystal X‐ray diffraction (1, 2) and 2D NMR experiments, which reveal discrete units of cationic mixed‐sandwich complexes of the composition [RuCp(*)(RTpm)]+ featuring η5‐cyclopentadienyl and κ3N‐coordinated RTpm ligands. The air‐sensitive salt [RuCp*(acn)(MeTpm)][PF6] (4) exhibits a κ2N‐coordinated MeTpm and one remaining acetonitrile ligand, presumably due to steric interactions between the sterically more bulky Cp* and MeTpm ligands. Cyclic voltammetric studies of the symmetric mixed‐sandwich complexes 1–3 in acetonitrile show quasi‐reversible oxidation processes centred at E01/2 = +0.38 (1), +0.15 V (2) and +0.35 V (3) vs. Fc/Fc+. These values are mainly affected by the different nature of the Cp ligands; the differently substituted RTpm entities have very little influence.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)
Mixed Valency at the Nearly Delocalized Limit: Fundamentals and Forecast (Eur. J. Inorg. Chem. 5/2009)
Authors: Glover Starla D. , Goeltz John C. , Lear Benjamin J. , Kubiak Clifford P. 
Published: January 2009

AbstractThe cover picture shows a Class II/III mixed‐valence system, {[Ru3O(OAc)6(CO)(pyridine)]2–pyrazine}–1, which undergoes picosecond intramolecular electron transfer (right). In nearly delocalized mixed‐valence complexes, rates of ET depend highly on solvent dynamics. Freezing of the solution causes a localized‐to‐delocalized transition, and rates of ET increase. We find that, for Class II/III mixed‐valence complexes, solvent dynamical parameters control rates of ET and tend to localize otherwise delocalized electronic states. Details are presented in the Microreview by C. P. Kubiak et al. on p. 585 ff.
Omphalotins E–I, Five Oxidatively Modified Nematicidal Cyclopeptides from Omphalotus olearius
Authors: Liermann Johannes C. , Opatz Till , Kolshorn Heinz , Antelo Luis , Hof Carolin , Anke Heidrun 
Published: January 2009

AbstractOmphalotins E–I, oxidatively modified cyclic dodecapeptides, were isolated from mycelial extracts of the basidiomycete Omphalotus olearius, and their structures were determined by NMR spectroscopic and MS methods. Four of the five omphalotins contained an unprecedented N‐hydroxylated tricyclic tryptophan derivative. All compounds exhibited strong and selective nematicidal activity against the plant pathogen Meloidogyne incognita with LD90 values between 2 and 5 μg mL–1. Cytotoxic activities were not detected up to 50 μg mL–1. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)
Analysis of aliphatic amines using head‐column field‐enhanced sample stacking in MEKC with LIF detection
Authors: Zhang Jianhua , Cui Huimin , Xu Liangjun , Zhang Lan , Chen Guonan 
Published: January 2009

AbstractThis paper describes the use of head‐column field‐enhanced sample stacking for on‐line sample concentration in MEKC; the method has been applied to the determination of C1∼C9 aliphatic amines after their pre‐capillary derivatization with 3‐(4‐carboxybenzoyl) quinoline‐2‐carboxaldehyde (CBQCA). The optimum derivatization, on‐line concentration and separation conditions for these aliphatic amines were investigated in detail. The optimized molar ratio of CBQCA to amines was found to be 120:1, and 50 mmol/L borate buffer (pH 9.5) was used for derivatization in order to achieve high efficiency. Nine imidazole aliphatic amines were baseline separated within 12 min by using 50 mmol/L of sodium borate (pH 9.5) and 15 mmol/L of SDS as running buffer. Under the optimum conditions, the detection limits of these nine aliphatic amines ranged from 1.2 to 3.8 pmol/L. S/N=3, which was about 49∼173‐fold lower than those of conventional sample injections. After validation, the developed method was applied to the determination of C1∼C9 aliphatic amines in river water with the average recoveries of 86.7∼105%.
Field‐amplified sample injection for the determination of albumin and transferrin in human urines by MEKC
Authors: Wu Yi‐Wei , Liu Jun‐Feng , Xiao Tang‐Xin , Han De‐Yan , Zhang Hai‐Li , Pan Ji‐Cheng 
Published: January 2009

AbstractAn MEKC method combining field‐amplified sample injection (FASI) has been developed for the analysis of albumin (Alb) and transferrin (TRF) in human urines. Various parameters affecting FASI preconcentration were optimized systematically. Under the optimum conditions, using electrokinetic sample injection for 90 s, the sensitivity was improved 77.6‐ and 45.3‐fold for TRF and Alb, respectively, without loss of separation efficiency when compared with hydrodynamical sample injection for 5 s (0.5 psi). The detection limits of TRF and Alb were found to be 0.31 and 0.14 mg/L, respectively. The proposed method has been successfully applied to the determination of TRF and Alb in desalted urines from patients with kidney diseases, and the recoveries of TRF and Alb were 91.1–101.7%.
Three New Dicoumarins from Daphne feddei
Authors: Liang Shuang , Shen Yun‐Heng , Tian Jun‐Mian , Wu Zhi‐Jun , Jin Hui‐Zi , Zhang Wei‐Dong , Yan Shi‐Kai 
Published: January 2009

Abstractmagnified imageA novel dicoumarinolignoid, feddeiticin (1), the first example with a dicoumarinolignoid skeleton, along with the two new dicoumarin glucosides 2 and 3, were isolated from the stem barks of Daphne feddei. The structures were elucidated on the basis of spectral analyses.
Synthesis of 4‐(Methoxycarbonyl)phenyl β‐Lactoside Derivatives Modified at C(6) or C(6′), and Evaluation of Their Inhibitory Activity on Erythrina cristagalli Lectin‐Mediated Hemagglutination
Authors: Butera Anna Paola , de Souza Filho José Dias , Prado Maria Auxiliadôra Fontes , Lisboa Marilda Pereira , Alves Ricardo José 
Published: January 2009

Abstractmagnified imageWe report herein the synthesis of 4‐(methoxycarbonyl)phenyl β‐lactoside and eight derivatives modified at C(6) or C(6′). These compounds were evaluated in hemagglutination inhibition assay using the lectin from Erythrina cristagalli. None of the compounds showed enhanced activity as compared to lactose.
The Absolute Configuration of the (+)‐ and (−)‐cis‐ and (+)‐ and (−)‐trans‐1‐Benzyl‐4‐hydroxypiperidine‐3‐methanols: An Unusual Application of the 1H‐NMR‐Mosher Method
Authors: Clerc Christian , Matarazzo Igor , Rüedi Peter 
Published: January 2009

Abstractmagnified imageThe enantiomerically pure title compounds were prepared and the absolute configurations assigned by the high‐field 1H‐NMR application of the Mosher method on the bis‐MTPA derivatives (MTPA=α‐methoxy‐α‐(trifluoromethyl)benzeneacetic acid). The final evidence for the adaptability of the procedure was effected by X‐ray crystallographic analyses. The absolute configurations of the cis‐ and trans‐1‐benzyl‐4‐hydroxypiperidine‐3‐methanols are as follows: (+)‐(3S,4S) and (−)‐(3R,4R) (cis), and (+)‐(3R,4S) and (−)‐(3S,4R) (trans), respectively (Scheme 2). Nonfermenting bakers' yeast reduction of methyl 1‐benzyl‐4‐oxopiperidine‐3‐carboxylate afforded (+)‐methyl (3R,4S)‐1‐benzyl‐4‐hydroxypiperidine‐3‐carboxylate (de>97%, ee>99%) which was further reduced to the (+)‐(3S,4S)‐diol (Scheme 3). The result confirms the stereochemical outcome of the biological reduction with re‐face selectivity and cis‐diastereoselectivity as predicted for bakers' yeast. The 4‐hydroxypiperidine‐3‐methanols are the key starting compounds for the synthesis of the enantiomerically pure P(3)‐axially and P(3)‐equatorially substituted cis‐ and trans‐configurated 8‐benzyl‐2,4‐dioxa‐8‐aza‐3‐phosphadecalin 3‐oxides (=8‐benzyl‐2,4‐dioxa‐8‐aza‐3‐phospha‐bicyclo[4.4.0]decane 3‐oxides) representing γ‐homo‐acetylcholine mimetics.
5‐Benzyl‐3‐methylimidazolidin‐4‐one‐Derived Reactive Intermediates of Organocatalysis – A Comforting Resemblance of X‐Ray, NMR, and DFT Solid‐Phase, Liquid‐Phase, and Gas‐Phase Structures
Authors: Grošelj Uroš , Schweizer W. Bernd , Ebert Marc‐Olivier , Seebach Dieter 
Published: January 2009

Abstractmagnified imageThe X‐ray crystal structures of three (E)‐1‐cinnamoylidene iminium PF6 salts of 5‐benzyl‐3‐methylimidazolidin‐4‐ones (2,2‐dimethyl‐, cis‐2‐(tert‐butyl)‐, and cis‐2‐styryl‐substituted; 2–4, resp.) are reported (Figs. 3–5). In the 2,2‐dimethyl and in the cis‐2‐styryl derivative, 2 and 4, respectively, a CH bond of the cis‐substituent in 2‐position points to the center of the benzene ring of the benzyl group above the five‐membered ring (Fig. 6, a and b). NMR Measurements (Fig. 8) provide evidence that the same structure is present in solution, and that a fourth derivative of this type, 5 (Scheme), has (Z)‐ instead of (E)‐configuration around the CN bond. In the cis‐2‐(tert‐butyl) derivative 3, the benzyl group is located over the iminium π‐system (Figs. 4 and 6, c). Overlays with DFT‐calculated crotonylidene analogs, A and B, show that the theoretical and experimental structures are almost superimposable (Fig. 9 and Table). The structures are discussed in view of their role as reactive intermediates in organocatalysis and in view of the help synthetic organic chemists may experience from theory.
Isotopic approach to understanding the groundwater flow system within an andesitic stratovolcano in a temperate humid region: case study of Ontake volcano, central Japan
Authors: Asai Kazuyoshi , Satake Hiroshi , Tsujimura Maki 
Published: January 2009

AbstractWe used isotope tracer methods to clarify the groundwater flow system within Mt Ontake: a stratovolcano consisting of andesite lava and pyroclastic rock, located within a temperate humid region. Precipitation was collected monthly at 11 sites on the south, east, north, and west slopes of the volcano for a period of 26 months. The weighted mean δ‐value in precipitation shows a clear decrease with increasing elevation (altitude effect) on all slopes and is relatively low on the leeward slope (rain‐shadowing effect). The springs collected over the entire area of the volcano show δ‐values that are controlled by the altitude effect and the rain‐shadowing effect on precipitation. The average recharge elevations of the individual springs were calculated from their δ18O‐values and the equation of the altitude effect of groundwater for corresponding slope. The average recharge elevation and tritium concentration in springs indicate that the large‐scale groundwater flow systems (vertical drop: ca 800 m) with a relatively long residence time are maintained along the lava flow in the younger volcano north zone, whereas relatively small‐scale groundwater flow systems (vertical drop: ca 400 m) are distributed across a wide range of elevations in the younger volcano south zone. In the older volcano zone at the foot of the volcano body, it is inferred that local groundwater flow systems (vertical drop: less than 200 m) dominate and that these flow systems are not connected to those in the younger volcano zone. Consequently, the scale of the groundwater flow system decreases with increasing age of the volcano body. This contraction of the flow system with time might reflect the progressive erosion of the volcano body, especially within the younger volcano zone. Copyright © 2009 John Wiley & Sons, Ltd.
Preparation of hydroxyapatite‐titania hybrid coatings on titanium alloy
Authors: Ün Serhat , Durucan Caner 
Published: January 2009

AbstractHydroxypapatite‐titania hybrid films on Ti6Al4V alloys were prepared by sol–gel technique by incorporating presynthesized hydroxypapatite (Ca10(PO4)6(OH)2 or HAp) powders into a titanium‐alkoxide dip coating solution. Titania network was formed by the hydrolysis and condensation of Ti‐isopropoxide Ti[OCH(CH3)2]4‐based sols. The effect of titania sol formulation, specifically the effect of organic solvents on the microstructure of the dip coated films calcined at 500°C has been investigated. The coatings exhibit higher tendency for cracking when a high vapor pressure solvent, such as ethanol (C2H5OH) is used causing development of higher macroscopic stresses during evaporation of the sol. Titania sol formulations replacing the solvent with n‐proponal (CH3(CH2)2OH) and acetly‐acetone (C5H8O) combinations enhanced the microstructural integrity of the coating during evaporation and calcination treatments. Sol–gel processing parameters, such as multilayer coating application and withdrawal rate, can be employed to change the titania thickness in the range of 0.120–1.1 μm and to control the microstructure of HAp‐titania hybrid coatings. A high‐calcination temperature in the range of 400–600°C does not cause a distinct change in crystals nature of the titania matrix or HAp, but results in more cracking due to the combined effect of densification originated stresses and thermal stresses upon cooling. Slower withdraw rates and multilayer dip coating lead to coatings more vulnerable to microcracking. © 2009 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2009
Development of a biomimetic collagen‐hydroxyapatite scaffold for bone tissue engineering using a SBF immersion technique
Authors: Al‐Munajjed Amir A. , Plunkett Niamh A. , Gleeson John P. , Weber Tim , Jungreuthmayer Christian , Levingstone Tanya , Hammer Joachim , O'Brien Fergal J. 
Published: January 2009

AbstractThe objective of this study was to develop a biomimetic, highly porous collagen‐hydroxyapatite (HA) composite scaffold for bone tissue engineering (TE), combining the biological performance and the high porosity of a collagen scaffold with the high mechanical stiffness of a HA scaffold. Pure collagen scaffolds were produced using a lyophilization process and immersed in simulated body fluid (SBF) to provide a biomimetic coating. Pure collagen scaffolds served as a control. The mechanical, material, and structural properties of the scaffolds were analyzed and the biological performance of the scaffolds was evaluated by monitoring the cellular metabolic activity and cell number at 1, 2, and 7 days post seeding. The SBF‐treated scaffolds exhibited a significantly increased stiffness compared to the pure collagen group (4‐fold increase), while a highly interconnected structure (95%) was retained. FTIR indicated that the SBF coating exhibited similar characteristics to pure HA. Micro‐CT showed a homogeneous distribution of HA. Scanning electron microscopy also indicated a mineralization of the collagen combined with a precipitation of HA onto the collagen. The excellent biological performance of the collagen scaffolds was maintained in the collagen‐HA scaffolds as demonstrated from cellular metabolic activity and total cell number. This investigation has successfully developed a biomimetic collagen‐HA composite scaffold. An increase in the mechanical properties combined with an excellent biological performance in vitro was observed, indicating the high potential of the scaffold for bone TE. © 2009 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2009