bluuebunny/crossref_metadata_2025_split huggingface dataset:
Production of Synthesis Gas via Methane Reforming with CO2 on Ni/SiO2 Catalysts Promoted by Alkali and Alkaline Earth Metals
Authors: Ping Chen , Zhao‐Yin Hou , Xiao‐Ming Zheng 
Published: August 2005

AbstractNi/SiO2 catalysts promoted by alkali metals K and Cs or alkaline earth metals Mg, Ca, Sr and Ba were prepared, characterized by H2‐TPR and XRD, and used for the production of synthesis gas via methane reforming with CO2. Though K and Cs promoted Ni catalysts could eliminate coke deposition, the reforming activity of these promoted catalysts was decreased heavily. Mg and Ca promoted Ni/SiO2 catalysts exhibited excellent coke resistance ability with minor loss of the reforming activity of Ni/SiO2. Ba showed poor coke resistance ability and small amount of Sr increased the formation of coke. The possible mechanism of these promoters was discussed.
Self‐inclusion of a New Calix[4]arene Derivative via Associated Acetonitrile: X‐ray Diffraction and Density Functional Theory Studies
Authors: Gao‐Sheng Yang , Ren Miao , Yi‐Zhi Li , Chen Jin , Jin Hong , Zi‐Jian Guo , Long‐Gen Zhu 
Published: August 2005

AbstractA new calix[4]arene derivative, 11,23‐bis(hydroxyiminomethyl)‐25,27‐dihydroxy‐26,28‐di‐n‐propoxycalix[4]arene (B), was synthesized and a compound, with composition of B·2CH3CN, was fully characterized. 1H NMR showed that B in the B·2CH3CN adopts a cone conformation. X‐ray diffraction analysis confirmed the conformation found in solution. In the crystal network, self‐inclusion phenomenon is present in a dimeric unit of B·2CH3CN via embedding each other. The noncovalent interaction energies were calculated at B3LYP/6‐311G(d) level and corrected by basis set superposition error (BSSE). In half a dimeric unit, one CH3CN is stabilized via hydrogen bonding formed between nitrogen atom of the acetonitrile and one hydroxyimino group, with bonding energy of −5.02 kJ·mol−1, and the other one stabilized by hydrogen bonding formed between nitrogen atom of the acetonitrile and the other hydroxyimino group, with bonding energy of −14.23 kJ·mol−1, and by inclusion to hydrophobic cavity of the other half of the dimeric unit via CH···π interaction, with bonding energy of −3.77 kJ·mol−1, doubling of which is a driving force for embedding two B·2CH3CN together.
Intramolecular Charge Transfer with 1‐Naphthanilides and 2‐Naphthanilides
Authors: Li‐Hong Liu , Lin Guo , Chun‐Hua Liu , Xuan Zhang , Yun‐Bao Jiang 
Published: August 2005

AbstractA series of 1‐naphthanilides (1) and 2‐naphthanilides (2) with varied substituents at the para‐ or meta‐position of anilino phenyl ring were prepared and their absorption and fluorescence spectra in a nonpolar solvent cyclohexane were investigated. An abnormal long wavelength emission assigned to the charge transfer (CT) state was found for all of the prepared naphthanilides in cyclohexane. A linear free energy correlation between the CT emission energies and the Hammett constants of the substituent was found within series 1 and 2. The value of the linear slope with 1 (0.42 eV) was higher than that with 2 (0.32 eV) being close to that of the substituted benzanilides 3 (0.31 eV). The higher slope value suggested higher charge separation extent in the CT state of 1 than that of 2. It was found that the corresponding linear slope of anilino‐substituted benzanilides remained unchanged when para‐, meta‐, ortho‐, or ortho, ortho‐methyls were introduced into the anilino moiety, which ruled out the possible contribution of the difference in the steric effect and the electron accepting ability of the naphthoyl acceptor in 1 and 2. Compared with the early reported N‐substituted‐benzoyl‐aminonaphthalene derivatives 4 and 5, it was considered that 1‐naphthoyl enhanced the charge transfer in 1 and the proximity of its 1La and 1Lb states was suggested to be responsible. It was shown that 1‐ and/or 2‐substituted naphthalene cores acting as either electron acceptor (naphthoyl) or electron donor (aminonaphthalene) were different in not only electron accepting (donating) ability but also shaping the charge transfer pathway.
dentification of Novel Pesticides and Impurities by the Combination of LC‐MS with GC‐MS Analysis
Authors: Su‐Yan Zhang , Yu Geng , Yin‐Long Guo , Hao Wang , Long Lü 
Published: August 2005

AbstractHigh performance liquid chromatography (HPLC) and electrospray ionization mass spectrometry (ESI‐MS) have been utilized to analyze the synthesized 2‐(2‐arylaminomethylphenoxy)pyrimidine derivatives, which are a new kind of environmentally benign herbicides and have passed the temporary pesticide registration. The identification of main product and impurities has been achieved according to the UV and mass spectra. Moreover, one impurity, introduced by the raw material in the last step of the synthetic route, was identified by GC‐MS analysis. It can be concluded that the combination of chromatography and mass spectrometry, including LC‐MS and GC‐MS, provided a vital tool of the pesticide science.
Synthesis, Structure and Biological Activities of Novel Triazole Compounds Containing Thioamide Group
Authors: Fa‐Qian Liu , Yong‐Qi Qin , Liang‐Zhong Xu , Lu‐De Lu , Xu‐Jie Yang , Xin Wang 
Published: August 2005

AbstractTwo compounds 2‐benzoyl‐N‐phenyl‐2‐(1,2,4‐triazol‐1‐yl)thioacetamide (1) and 2‐(4‐chlorobenzoyl)‐N‐phenyl‐ 2‐(1,2,4‐triazol‐1‐yl)thioacetamide (2) were synthesized from substituted acetophenone, triazole and phenyl isothiocyanate by several step reactions. The structure of compound 1 was determined by single‐crystal X‐ray diffraction analysis. It crystallizes in monoclinic system with space group P21/c, a=0.8806(2) nm, b=1.2097(2) nm,c=1.4809(3) nm, β=105.88°, Z=4, V=1.5173(6) nm3, Dc=1.411 Mg/m3, μ=0.22 mm‐1, F(000)=672, finalR1=0.040 and Rw=0.103. There is obvious potentially weak CH···N intermolecular interaction in the crystal, which stabilizes the structure. The results of biological test show that the two compounds have antifungal and plant growth regulating activities.
Two New Oxoaporphine Alkaloids from Thalictrum elegans
Authors: Zhi‐Yuan Liang , Xiao‐Sheng Yang , Ye Wang , Xiao‐Jiang Hao 
Published: August 2005

AbstractTwo new oxoaporphine alkaloids, 1,2,3,10‐tetramethoxy‐9‐(2‐hydroxy‐4,5‐dimethoxybenzyloxy)oxoaporphine (1) and 1,2,3,10‐tetramethoxy‐9‐(4,5‐dimethoxy‐2‐formylphenoxy)oxoaporphine (2), were isolated from Thalictrum elegans. Their structures were elucidated based on spectroscopic analysis including 1D, 2D NMR, IR and MS.
Spectroscopic Interrogation of Layer‐by‐layer Assembled Films of Conjugated Polyelectrolytes
Authors: Hai‐Ping Wu , Hui Xu , Chun‐Hai Fan 
Published: August 2005

AbstractLayer‐by‐layer fluorescent conjugated polyelectrolyte films have been studied. The photoluminescence of conjugate polyelectrolytes was observed to be highly tunable during this film assembly process. Efficient photoinduced electron transfer from thus prepared highly luminescent film to a natural electron‐transfer protein cytochrome c has also been observed.
A deterministic‐control‐based approach motion by curvature
Authors: Kohn Robert , Serfaty Sylvia 
Published: August 2005

AbstractThe level‐set formulation of motion by mean curvature is a degenerate parabolic equation. We show that its solution can be interpreted as the value function of a deterministic two‐person game. More precisely, we give a family of discrete‐time, two‐person games whose value functions converge in the continuous‐time limit to the solution of the motion‐by‐curvature PDE. For a convex domain, the boundary's “first arrival time” solves a degenerate elliptic equation; this corresponds, in our game‐theoretic setting, to a minimum‐exit‐time problem. For a nonconvex domain the two‐person game still makes sense; we draw a connection between its minimum exit time and the evolution of curves with velocity equal to the “positive part of the curvature.” These results are unexpected, because the value function of a deterministic control problem is normally the solution of a first‐order Hamilton‐Jacobi equation. Our situation is different because the usual first‐order calculation is singular. © 2005 Wiley Periodicals, Inc.
Characterization of antibodies that inhibit HIV gp120 antigen processing and presentation
Authors: Tuen Michael , Visciano Maria Luisa , Chien Peter C. , Cohen Sandra , Chen Pei‐de , Robinson James , He Yuxian , Pinter Abraham , Gorny Miroslaw K. , Hioe Catarina E. 
Published: August 2005

AbstractAntibodies to the CD4‐binding site (CD4bs) of HIV‐1 envelope gp120 have been shown to inhibit MHC class II presentation of this antigen, but the mechanism is not fully understood. To define the key determinants contributing to the inhibitory activity of these antibodies, a panel of anti‐CD4bs monoclonal antibodies with different affinities was studied and compared to antibodies specific for the chemokine receptor‐binding site or other gp120 regions. Anti‐CD4bs antibodies that completely obstruct gp120 presentation exhibit three common properties: relatively high affinity for gp120, acid‐stable interaction with gp120, and the capacity to slow the kinetics of gp120 proteolytic processing. None of these antibodies prevents gp120 internalization into APC. Notably, the broadly virus‐neutralizing anti‐CD4bs IgG1b12 does not block gp120 presentation as strongly, because although IgG1b12 has a relatively high affinity, it dissociates from gp120 more readily at acidic pH and only moderately retards gp120 proteolysis. Other anti‐gp120 antibodies, regardless of their affinities, do not affect gp120 presentation. Hence, high‐affinity anti‐CD4bs antibodies that do not dissociate from gp120 at endolysosomal pH obstruct gp120 processing and prevent MHC class II presentation of this antigen. The presence of such antibodies could contribute to the dearth of anti‐gp120 T helper responses in chronically HIV‐1‐infected patients.
Differential expression of human granzymes A, B, and K in natural killer cells and during CD8+ T cell differentiation in peripheral blood
Authors: Bratke Kai , Kuepper Michael , Bade Britta , Virchow J. Christian , Luttmann Werner 
Published: August 2005

AbstractNK cells and cytotoxic T lymphocytes can induce apoptosis in virus‐infected and transformed target cells via the granule exocytosis pathway. The key components of the cytolytic granules are perforin and several serine esterases, termed granzymes. While the cellular distribution of human granzymes A (GrA) and B (GrB) has been well characterized much less is known about the expression pattern of human granzyme K (GrK). In this study GrA, GrB, and GrK expression was analyzed in human peripheral blood lymphocytes using flow cytometry. There was a distinct population of GrK expressing CD8+ T cells with a CD27+/CD28+/CCR5high/CCR7–/perforin–/low/IFN‐γ+ memory‐like phenotype, while all CD56bright NK cells were also positive for GrK. In addition, GrK was also expressed in subpopulations of CD56+ T cells, CD4+ T cells, and TCRγδ+ T cells. In contrast, GrB was primarily expressed in CD56dim NK cells and differentiated memory CD8+ T cells with the CD27–/low/CD28–/low/CCR5–/low/CCR7–/CD11b+/perforinhigh phenotype. Only few CD8+ T cells expressed both GrB and GrK. GrA was found to be co‐expressed in all GrB‐ and GrK‐expressing T cells. Our findings suggest that granzyme expression during the differentiation process of memory CD8+ T cells might be as follows: GrA+/GrB–/GrK+ → GrA+/GrB+/GrK+ → GrA+/GrB+/GrK–.
Soluble, dimeric HLA DR4‐peptide chimeras: An approach for detection and immunoregulation of human type‐1 diabetes
Authors: Preda Ioana , McEvoy Robert C. , Lin Marvin , Bona Constantin A. , Rapaport Robert , Brumeanu Teodor D. , Casares Sofia 
Published: August 2005

AbstractStill there are no effective methods to predict or cure type 1 diabetes (T1D) in humans. Soluble, dimeric MHC class II‐peptide (DEF) chimeras have potential for both early diagnosis and immunospecific therapy. DEF chimeras prevent and reverse diabetes in mice by stimulating antigen‐specific type 1 T regulatory cell (Tr1)‐like cells. We also showed that diabetes could be predicted by changes in the phenotype of autoreactive CD4 T cells in peripheral blood. Herein, we demonstrated that human DEF (HLA‐DR*0401/Fcγ1) chimeras expressing peptides of β‐cell antigens stimulate Tr1‐like cells in blood of patients with T1D, non‐diabetic relatives, and controls. Furthermore, the specific and stable binding of DEF chimeras to cognate TCR and CD4 coreceptor allowed quantification and phenotyping of autoreactive CD4 T cells in non‐stimulated blood by FACS. Our results indicate that (1) autoreactive CD4 T cells to GAD65 autoantigen are commonly present in humans expressing diabetes‐susceptible HLA‐DR*0401 molecules; (2) these autoreactive T cells undergo avidity maturation upon encountering the self antigen early in life; (3) the disease is associated with an imbalance between autoreactive CD4+CD25+ and CD4+CD69+ T cells specific for GAD65. Based on this, we propose a model to explain the kinetics of autoreactive CD4 T cells in blood during the natural history of T1D.
Expansion of CD4 T cells expressing a highly restricted TCR structure specific for a single parasite epitope correlates with high pathology in murine schistosomiasis
Authors: Finger Eduardo , Brodeur Peter H. , Hernandez Hector J. , Stadecker Miguel J. 
Published: August 2005

AbstractThe hepatic immunopathology in schistosomiasis mansoni is mediated by CD4 T cells specific for egg antigens and varies considerably among mouse strains. Previous studies in high pathology C3H mice suggested that a strong T cell response was due to the recognition of an immunodominant epitope within the major egg antigen Sm‐p40 (Sm‐p40234–246). Using a panel of T cell hybridomas, we have now examined the egg antigen‐specific TCR repertoire in two high pathology strains, C3H and CBA. We found that nearly half of the hybridomas responded to the Sm‐p40234–246 epitope and, of these, nearly all expressed Vα11.3 associated with Vβ8. Furthermore, in response to egg antigen stimulation, transcript levels of Vα11.3J36 (the most prevalent rearrangement expressed by Sm‐p40234–246‐specific hybridomas), increased in high pathology (CBA) but not in low pathology (BALB/c) strains. Our findings suggest that exacerbated schistosome egg‐induced immunopathology can be driven by T cells expressing a highly restricted TCR structure specific for a single parasite epitope.
Understanding what makes a good versus a bad vaccine
Authors: Harari Alexandre , Pantaleo Giuseppe 
Published: August 2005

AbstractThe majority of the HIV vaccines under development are aimed at stimulating T cell responses. Therefore, it is critical to delineate the factors regulating the generation of the T cell responses and to develop strategies maximizing vaccine‐induced T cell responses. The identification of these factors and the delineation of the kinetics of the generation of vaccine‐induced immune responses have been hard to investigate, due to the limited number of precursor naive antigen‐specific T cells. To overcome these obstacles, Estcourt and collaborators have developed an elegant strategy that consists of an in vivo mouse model employing transfer of naive CFSE‐labeled TCR‐transgenic T lymphocytes into syngeneic nontransgenic recipients prior to vaccination. Using this model, the authors demonstrate that the dose, the route of administration and the type of vaccine determine the magnitude, the dissemination and the kinetics of vaccine‐induced T cell responses. Furthermore, the mouse model of Estcourt and collaborators may represent the basis for the development of powerful in vivo experimental strategies to evaluate vaccine candidates.See accompanying article: http://dx.doi.org/10.1002/eji.200535184
The Reaction Mechanism of Spirocylization and Stereoselectivity Studies for the Calyculin C16–C25 Fragment
Authors: Rauhala Vesa , Nättinen Kalle , Rissanen Kari , Koskinen Ari M. P. 
Published: August 2005

AbstractThe mechanism of the double intramolecular hetero‐Michael addition, a key reaction in the planned synthesis of the natural product calyculin C, has been studied by NMR. The cyclization follows Baldwin’s rules and proceeds first through a six‐membered ring closure (6‐endo‐dig), followed by a five‐membered ring cyclization (5‐exo‐trig). (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
New Building Blocks Based on Truxene Cores: Synthesis of Functionalized syn‐Tri‐ and ‐Hexasubstituted Derivatives
Authors: González‐Cantalapiedra Esther , Ruiz Marta , Gómez‐Lor Berta , Alonso Beatriz , García‐Cuadrado Domingo , Cárdenas Diego J. , Echavarren Antonio M. 
Published: August 2005

AbstractHexasubstituted truxenes are obtained in one step by alkylation of the potassium anion of truxene. Subsequent derivatization provides truxene derivatives with six carboxy, amino, or hydroxy groups at their peripheries. Alkylation of syn‐5,10,15‐tribenzyl derivatives with a different benzyl bromide derivative affords mixtures of anti‐ and syn‐hexasubstituted truxenes. Truxenes with phenols or benzoquinone groups have also been synthesized by starting from truxenetrione. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
Stripping Voltammetry of Mercury(II) with a Chemically Modified Carbon Paste Electrode Containing Silica Gel Functionalized with 2,5‐Dimercapto‐1,3,4‐thiadiazole
Authors: Filho Newton L. Dias , Ribeiro do Carmo Devaney 
Published: August 2005

AbstractThe accumulation voltammetry of mercury(II) was investigated at a carbon paste electrode chemically modified with silica gel functionalized with 2,5‐dimercapto‐1,3,4‐thiadiazole (DTTPSG‐CPE). The repetitive cyclic voltammogram of mercury(II) solution in the potential range −0.2 to +0.8 V (vs. Ag/AgCl), (0.02 mol L−1 KNO3 ; v=20 mV s−1) show two peaks one at about 0.0 V and other at 0.31 V. However, the cathodic wave peak, around 0.0 V, is irregular and changes its form in each cycle. This peak at about 0.0 V is the reduction current for mercury(II) accumulated in the DTTPSG‐CPE. The anodic wave peak at 0.31 V is well‐defined and does not change during the cycles. The resultant material was characterized by cyclic and differential pulse anodic stripping voltammetry performed with the electrode in differents supporting electrolytes. The mercury response was evaluated with respect to pH, electrode composition, preconcentration time, mercury concentration, “cleaning” solution, possible interferences and other variables. The precision for six determinations (n=6) of 0.05 and 0.20 mg L−1 Hg(II) was 2.8 and 2.2% (relative standard deviation), respectively. The method was satisfactory and used to determine the concentration of mercury(II) in natural waters contaminated by this metal.
Testing bedload transport formulae using morphologic transport estimates and field data: lower Fraser River, British Columbia
Authors: Martin Yvonne , Ham Darren 
Published: August 2005

AbstractMorphologic transport estimates available for a 65‐km stretch of Fraser River over the period 1952–1999 provide a unique opportunity to evaluate the performance of bedload transport formulae for a large river over decadal time scales. Formulae tested in this paper include the original and rational versions of the Bagnold formula, the Meyer‐Peter and Muller formula and a stream power correlation. The generalized approach adopted herein does not account for spatial variability in flow, bed structure and channel morphology. However, river managers and engineers, as well as those studying rivers within the context of long‐term landscape change, may find this approach satisfactory as it has minimal data requirements and provides a level of process specification that may be commensurable with longer time scales. Hydraulic geometry equations for width and depth are defined using morphologic maps based on aerial photography and bathymetric survey data. Comparison of transport predictions with bedload transport measurements completed at Mission indicates that the original Bagnold formula most closely approximates the main trends in the field data. Sensitivity analyses are conducted to evaluate the impact of inaccuracies in input variables width, depth, slope and grain size on transport predictions. The formulae differ in their sensitivity to input variables and between reaches. Average annual bedload transport predictions for the four formulae show that they vary between each other as well as from the morphologic transport estimates. The original Bagnold and Meyer‐Peter and Muller formulae provide the best transport predictions, although the former underestimates while the latter overestimates transport rates. Based on our findings, an error margin of up to an order of magnitude can be expected when adopting generalized approaches for the prediction of bedload transport. Copyright © 2005 John Wiley & Sons, Ltd.
Quantifying the effect of a freeze–thaw cycle on soil erosion: laboratory experiments
Authors: Ferrick M. G. , Gatto L. W. 
Published: August 2005

AbstractIn this paper we quantitatively test the hypothesis that soil freeze–thaw (FT) processes significantly increase the potential for upland hillslope erosion during run‐off events that follow thaw. We selected a highly frost‐susceptible silt to obtain an upper bound on FT effects, and completed three series of six experiments each to quantify differences in soil erosion and rill development in a bare soil following a single FT cycle. Each series represented a specific soil moisture range: 16–18 per cent, 27–30 per cent and 37–40 per cent by volume, with nominal flow rates of 0·4, 1·2 and 2·4 L/min and slopes of 8° and 15°. Each experiment used two identical soil bins: one a control (C) that remained unfrozen, and another that was frozen and thawed once. Standard soil characterization tests did not detect significant differences between the FT and C bins. We measured cross‐sectional geometry of an imposed straight rectangular rill before each experiment, sediment load during and rill cross‐sections after. Changes in cross section provided detailed measures of erosion at specific locations, while sediment load from time series run‐off samples integrated the rill erosion. Several parameters, including average maximum rill width, average maximum rill depth, rill cross‐section depth measures and sediment load, all followed similar trends. Each was greater in the FT than in the C, with values that generally increased with slope and flow. However, soil moisture was the only parameter that affected the FT/C ratios. Average sediment load grouped by soil moisture provided FT/C ratios of 2·4, 3·0 and 5·0 for low, mid and high moisture, respectively. In contrast, a ‘dry’ experiment at 4–5 per cent soil moisture had FT/C of 1·02 for sediment load. These results show a dramatic increase with soil moisture in the rate and quantity of bare soil eroded due to the FT cycle. As both FT and C results were highly sensitive to initial conditions, minimum differences in soil weight, bulk density and soil moisture through each series of experiments were required to achieve consistent results, indicating that rill erosion may be chaotic. Published in 2005 by John Wiley & Sons, Ltd.