bluuebunny/crossref_metadata_2025_split huggingface dataset:
Mechanistic Insights into Acetophenone Transfer Hydrogenation Catalyzed by Half‐Sandwich Ruthenium(II) Complexes Containing 2‐(Diphenylphosphanyl)aniline – A Combined Experimental and Theoretical Study
Authors: Bacchi Alessia , Balordi Marcella , Cammi Roberto , Elviri Lisa , Pelizzi Corrado , Picchioni Filippo , Verdolino Vincenzo , Goubitz Kees , Peschar René , Pelagatti Paolo 
Published: August 2008

AbstractSeveral new half‐sandwich ruthenium(II) complexes containing 2‐(diphenyphosphanyl)aniline (PNH2) of formula {Ru[(κ2P,N)PNH2](p‐cymene)Cl}Y [Y = Cl (1a), PF6 (1b), BF4 (1c), BPh4 (1d), TfO (1e)] were synthesized and fully characterized both in solution (1H NMR and 31P{1H} NMR spectroscopy) and in the solid state (FTIR, X‐ray analysis on single crystal). Complexes 1a and 1b are active precatalysts in the hydrogen transfer reaction of acetophenone, leading to tof values up to 4440 h–1. In comparison, the {Ru[(κ2P,N)PNMe2](p‐cymene)Cl}Cl complex leads to a tof value of 100 h–1 under the same catalytic conditions. The mechanism through which the precatalysts operate was deeply explored by high‐resolution MS (ESI) and DFT/PCM studies. The results reveal that the complexes containing PNH2 operate through a bifunctional mechanism analogous to that proposed for diamines and amino alcohol ligands. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
An Assessment of the Potential Relationship between the Charge of Gd–DTPA Complexes and the Exchange Rate of the Water Coordinated to the Metal
Authors: Laurent Sophie , Vander Elst Luce , Botteman François , Muller Robert N. 
Published: August 2008

AbstractThe residence time of coordinated water (τM), a parameter of paramount importance for relaxivity, is compared in a series of Gd–DTPA derivatives carrying different global charges. The importance of the charge in the first coordination sphere of the metal and in its vicinity is reported. Neutral bisester and bisamide complexes have significantly different τM values. The paradoxical similarity of the exchange rates of bisester complexes and Gd–DTPA, on the one hand, and the large difference between neutral bisester and bisamide complexes, on the other hand, suggest that the charge inside the first coordination sphere is not the factor dominating the water exchange rate, which seems therefore more sensitive to the steric congestion. The study of Gd–(S)‐N6–carboxymethyl–DTPA, Gd–DTPA–BHydroxamide at basic pH, and Gd–DTPA–BAlaA clearly shows that anionic groups located outside the first coordination sphere have a beneficial influence on the value of τM, but that this effect strongly decreases with an increasing distance between the anionic group and the coordinated water. These conclusions underline the influence of steric hindrance and of the charged groups present in close proximity of the first coordination sphere on the exchange rate of the coordinated water. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
Di‐, Tetra‐, and Polynuclear Copper(II) Complexes: Active Catalysts for Oxidation of Toluene and Benzene
Authors: Roy Partha , Dhara Koushik , Manassero Mario , Banerjee Pradyot 
Published: August 2008

AbstractThree copper(II) complexes with a binucleating N2O donor ligand, [Cu2(L1)(μ2‐pz)(CH3COO)2] (1), [Cu4(L1)2(μ4‐O)(μ2‐CH3COO)2(μ1,1‐N3)(N3)] (2), and [Cu2(L2)(μ1,1‐N3)(μ1,3‐N3)2]∞(3) [pz = pyrazolato, HL1= 2,6‐bis(morpholinomethyl)‐4‐tert‐butylphenol and HL2= 2,6‐bis(morpholinomethyl)‐4‐methylphenol] have been synthesized and characterized by elemental analysis, FTIR and UV/Vis spectroscopy, and X‐ray crystallography. X‐ray crystallographic studies revealed that a series of di‐, tetra‐, and polynuclear complexes have been formed by varying the bridging ligand, counteranion, and reaction conditions. These show effective catalytic properties for the hydrogen peroxide oxidation of toluene and benzene. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
Synthesis and Structures of Triorganochalcogenium (Te, Se, S) Dinitramides
Authors: Klapötke Thomas M. , Krumm Burkhard , Scherr Matthias 
Published: August 2008

AbstractThe syntheses of the triorganochalcogenium dinitramide salts [Ph3Te][N(NO2)2] (1), [Me3Te][N(NO2)2] (2), [Ph3Se][N(NO2)2] (3), [Me3Se][N(NO2)2] (4), [Ph3S][N(NO2)2] (5), and [Me3S][N(NO2)2] (6), their characterization by multinuclear NMR spectroscopy, vibrational spectra, and single‐crystal structures are described. The syntheses of the compounds were achieved with the help of [Ag(py)2][N(NO2)2] and [Ag(NCCH3)][N(NO2)2] as dinitramide transfer reagents. Whereas in the crystal structure of 1 different coordination modes to dinitramide moieties are present, the crystal structure of 3 shows only a single intermolecular contact to the dinitramide moiety. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
Mo‐Catalyzed Cross‐Metathesis Reaction of Propynylferrocene (Eur. J. Inorg. Chem. 25/2008)
Authors: Bobula Tomáš , Hudlický Jason , Novák Petr , Gyepes Róbert , Císařová Ivana , Štěpnička Petr , Kotora Martin 
Published: August 2008

AbstractThe cover picture shows the reaction scheme for the cross‐metathesis of (prop‐1‐yn‐1‐yl)ferrocene with substituted propynes effected by catalysts generated from [Mo(CO)6] and halophenols, situated on a background full of typical ferrocene, autumn‐like colors. The metathesis reaction affords good yields of unsymmetric ferrocenyl alkynes, thus offering a new alternative approach toward their preparation. Also shown are the crystal structure of methyl 4‐[(ferrocenyl)ethynyl]benzoate and the orbital diagram of its solid‐state π···π stacked dimer as calculated by DFT methods. A survey of various substrates and catalysts, results of X‐ray structure analysis and DFT calculations as well as electrochemical data for a series of (phenylethynyl)ferrocenes substituted at the phenyl ring are discussed in the article by M. Kotora, P. Štěpnička et al. on p. 3911 ff.
A Practical Access to 1,2‐Diaminophytosphingolipids
Authors: Harrak Youssef , Llebaria Amadeu , Delgado Antonio 
Published: August 2008

AbstractA practical approach to the synthesis of phytosphingolipids containing the 1,2‐diamino framework is described. The methodology relies on the regioselective ring‐opening of phytosphingosine‐derived N‐nosylaziridines 4 and 6 with primary or secondary amines, acylation and subsequent deprotection steps. For practical purposes, N‐substituted benzylamines were used as protected primary amine surrogates to avoid side‐reactions in the course of the N‐nosyl deprotection step.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
Assessing the effect of clustered and biased multi‐stage sampling
Authors: Menezes Raquel , Tawn Jonathan 
Published: August 2008

AbstractWe propose a method for detecting biased multi‐stage sampling of spatial data and a method to adjust for biased clustering of samples. We assess the effect of these methods for the analysis of radioactivity contamination data from Rongelap island, with the scientific problem being the estimation of the maximum level of radioactivity over the island. These data were collected over a two‐stage process of uniform and clustered samples, which may have an impact on conclusions from a standard analysis that does not account for either of these features. Copyright © 2008 John Wiley & Sons, Ltd.
Risk assessment before and after solar photocatalytic degradation of BTEX contaminated groundwater at a gas station site in Korea
Authors: Cho Il‐Hyoung , Choi Kyungho , Kang Hojeong , Zoh Kyung‐Duk 
Published: August 2008

AbstractWe assessed the incremental lifetime risks due to groundwater contamination with benzene, toluene, ethylbenzene, and xylene compounds (BTEX) for residents living on the site of a former gas station. Five remedial processes were applied to examine the degradation pattern of groundwater samples under similar weather conditions in winter: H2O2/solar light (action 1), immobilized TiO2/solar light (action 2), TiO2 slurry/solar light (action 3), immobilized TiO2/solar light/H2O2 (action 4), and TiO2 slurry/solar light/H2O2 (action 5). None of the remedial actions satisfied the criteria of acceptable risk (1 × 10−6 for carcinogens) using point estimation with both central tendency exposure (CTE) and reasonable maximum exposure (RME) for all pathways via designated exposure scenarios. Regarding the total hazard index (HI) for noncarcinogens, only action 5 satisfied all the exposure scenarios, both CTE and RME, for toluene, ethylbenzene, and xylene compounds, whereas the total health risk for benzene was between 10−5 and 10−6 for carcinogens. Results of probabilistic estimation before and after the treatment of benzene with action 5 using a Monte Carlo simulation were 68.1% for males (95% CI: 5.0 × 10−7 to 3.9 × 10−6) and 74.2% for females (95% CI: 5.0 × 10−7 to 4.6 × 10−6), exceeding the criteria of acceptable risk (10−6 for carcinogens). However, no adverse health risk was posed if remedial action 5 or an increased reaction time were applied. This study is a new attempt to integrate issues of groundwater contamination based on concentration and health risk assessment associated with different ex situ remedial actions. © 2008 American Institute of Chemical Engineers Environ Prog, 2008
Spatial memory and the monkey hippocampus: Not all space is created equal
Authors: Lavenex Pamela Banta , Lavenex Pierre 
Published: August 2008

AbstractStudies of the role of the monkey hippocampus in spatial learning and memory, however few, have reliably produced inconsistent results. Whereas the role of the hippocampus in spatial learning and memory has been clearly established in rodents, studies in nonhuman primates have made a variety of claims that range from the involvement of the hippocampus in spatial memory only at relatively longer memory delays, to no role for the hippocampus in spatial memory at all. In contrast, we have shown that selective damage restricted to the hippocampus (CA regions) prevents the learning or use of allocentric, spatial relational representations of the environment in freely behaving adult monkeys tested in an open‐field arena. In this commentary, we discuss a unifying framework that explains these apparently discrepant results regarding the role of the monkey hippocampus in spatial learning and memory. We describe clear and strict criteria to interpret the findings from previous studies and guide future investigations of spatial memory in monkeys. Specifically, we affirm that, as in the rodent, the primate hippocampus is critical for spatial relational learning and memory, and in a time‐independent manner. We describe how claims to the contrary are the result of experimental designs that fail to recognize, and control for, egocentric (hippocampus‐independent) and allocentric (hippocampus‐dependent) spatial frames of reference. Finally, we conclude that the available data demonstrate unequivocally that the central role of the hippocampus in allocentric, spatial relational learning and memory is conserved among vertebrates, including nonhuman primates. © 2008 Wiley‐Liss, Inc.
Distinct hippocampal regions make unique contributions to relational memory
Authors: Giovanello Kelly Sullivan , Schnyer David , Verfaellie Mieke 
Published: August 2008

AbstractNeuroscientific research has shown that the hippocampus is important for binding or linking together the various components of a learning event into an integrated memory. In a prior study, we demonstrated that the anterior hippocampus is involved in memory for the relations among informational elements to a greater extent that it is involved in memory for individual elements (Giovanello et al., 2004. Hippocampus 14:5–8). In the current study, we extend those findings by further specifying the role of anterior hippocampus during relational memory retrieval. Specifically, anterior hippocampal activity was observed during flexible retrieval of learned associations, whereas posterior hippocampal activity was detected during reinstatement of study episodes. These findings suggest a functional dissociation across the long axis of human hippocampus based on the nature of the mnemonic process rather than the stage of memory processing or type of stimulus. © 2008 Wiley‐Liss, Inc.
Room‐Temperature Alkyne–Nitrile Metathesis and Unambiguous Proof for the Existence of a High‐Valent Iron‐Nitrido Dication in the Gas Phase. Short Communication
Authors: Boyd John P. , Schlangen Maria , Grohmann Andreas , Schwarz Helmut 
Published: August 2008

AbstractAn unprecedented alkyne–nitrile metathesis takes place when the high‐valent iron‐nitrido dication [Fe(L)N]2+, with L=2,6‐bis(2‐methyl‐1,3‐diaminopropan‐2‐yl)pyridine, is reacted with alkynes in the gas phase under thermal conditions. While the detailed role of the alkyne substrate with respect to relative rates, regioselectivities, and branching ratios remains to be elucidated, the very existence of this novel metathesis reaction provides additional experimental evidence of a genuine, long‐lived, formal iron(V)‐nitrido dication.
On the Adsorption and Reduction of the Herbicide Picloram on Mercury and Carbon Electrodes
Authors: Rodríguez Mellado Jose M. , Pintado Sara , Ruiz Montoya Mercedes 
Published: August 2008

AbstractAt concentrations higher than 2⋅10−4 M, and below pH 3, the cyclic voltammograms of picloram (=4‐amino‐3,5,6‐trichloropyridine‐2‐carboxylic acid) on Hg electrodes show two prepeak systems (named I and II attending to the proximity to the main reductions peak), which can be attributed to the weak adsorption of reactant and the strong adsorption of the product at the electrode surface. The system II is due to the uncharged form of picloram, and system I to the picloram protonated at the pyridine N‐atom. Small amounts of the surfactant Triton X‐100 (=α‐[4‐(1,1,3,3‐tetramethylbutyl)phenyl]‐ω‐hydroxypoly(oxyethane‐1,2‐diyl)) cause the disappearance of system I, the shift of system II, and also affect the intensities and widths of anodic and cathodic peaks but not the charge passed in each peak. Thus, the adsorption process responsible for the appearance of system I is inhibited by the presence of Triton; by contrast, the process corresponding to system II is only modified by the surfactant, becoming an electrochemical process occurring at the potentials corresponding to system II, which is more reversible than that observed in the absence of Triton. The addition of Triton permitted the analysis of the main reduction process. Convolution voltammetry of the main reduction peak is consistent with the loss of a Cl‐atom in equilibrium which occurs after a reversible electron transfer and is followed by the reductions of both species present in the equilibrium (Scheme 2). This is also the reduction mechanism on a glassy carbon electrode but the electron transfer on the carbon electrode increases with respect to the mercury electrodes; in addition, the loss of the Cl‐atom does not take place on the electrode surface. From the recording of differential capacity–potential curves, it was concluded that picloram is adsorbed on the carbon electrode; but this adsorption is too weak to induce the appearance of prepeak systems.
The ‘Azirine/Oxazolone Approach’ to the Synthesis of Aib‐Pro Endothiopeptides
Authors: Budzowski Artur , Linden Anthony , Heimgartner Heinz 
Published: August 2008

AbstractThe reaction of methyl N‐(2,2‐dimethyl‐2H‐azirin‐3‐yl)‐L‐prolinate (2a) with thiobenzoic acid at room temperature gave the endothiopeptide Bz‐AibΨ[CS]‐Pro‐OMe (7) in high yield. In an analogous manner, (benzyloxy)carbonyl (Z)‐protected proline was transformed into the thioacid, which was reacted with 2a to give the endothiotripeptide Z‐Pro‐AibΨ[CS]‐Pro‐OMe (12). The corresponding thioacid of 7 was prepared in situ via saponification, formation of a mixed anhydride, and treatment with H2S. A second reaction with 2a led to the endodithiotetrapeptide 9, but extensive epimerization at Pro2 was observed. Similarly, saponification of 12 and coupling with either 2a or H‐Phe‐OMe and 2‐(1H‐benzotriazol‐1‐yl)‐1,1,3,3‐tetramethyluronium tetrafluoroborate/1‐hydroxy‐1H‐benzotriazole (TBTU/HOBt) gave the corresponding endothiopeptides as mixtures of two epimers. The synthesis of the pure diastereoisomer BzΨ[CS]‐Aib‐Pro‐AibΨ[CS]‐N(Me)Ph (21) was achieved via isomerization of 7 to BzΨ[CS]‐Aib‐Pro‐OMe (16), transformation into the corresponding thioacid, and reaction with N,2,2‐trimethyl‐N‐phenyl‐2H‐azirin‐3‐amine (1a). The structures of 12 and 21 were established by X‐ray crystallography.
Two New Spirostanol Saponins from Reineckia carnea
Authors: Zhang Zhong‐Quan , Chen Jian‐Chao , Zhang Xian‐Ming , Li Zhong‐Rong , Qiu Ming‐Hua 
Published: August 2008

AbstractTwo new spirostanol saponins, (1β,3β,5β,25S)‐spirostan‐1,3‐diol 1‐(β‐D‐xylopyranoside) (1) and (1β,3β,5β,25S)‐spirostan‐1,3‐diol 1‐[α‐L‐rhamnopyranosyl‐(1→2)‐β‐D‐fucopyranoside] (2), along with two known compounds, (1β,3β,5β,25S)‐spirostan‐1,3‐diol 1‐[α‐L‐rhamnopyranosyl‐(1→2)‐β‐D‐xylopyranoside] (3) and (1β,3β,4β,5β,25S)‐spirostan‐1,3,4,5‐tetrol 5‐(β‐D‐glucopyranoside) (4) were isolated from the whole plant of Reineckia carnea. The structures of the new steroids were determined by detailed analysis of their 1D‐ and 2D‐NMR spectra and chemical methods, and by comparison with spectral data of known compounds. Compounds 3 and 4 were isolated from the genus Reineckia for the first time.
Discharge characteristics at the control point for rainfall runoff model application
Authors: Hwang Man H. , Maeng Seung J. , Lee Sang J. , Lee Bae S. , Koh Ick H. 
Published: August 2008

AbstractTo manage and distribute water resources efficiently, a rainfall runoff model must be selected and established. To determine the appropriations for this rainfall runoff model, however, accurate flow data must first be obtained. Thus, in this study, the simulated flow of Korea's Geum River was compared with the observed flow at Gongju point, a main control point, using the Streamflow Synthesis and Reservoir Regulation (SSARR) model. The results obtained showed a huge difference between the simulated and observed flows during the low flow period. To determine what caused this difference, a confidence analysis of the formula of the stage discharge curve at Gongju point, developed by the Ministry of Construction and Transportation's Geum River Flood Control Office, was conducted. The flow during the low flow period (between 2003 and 2005) was also measured, and the value obtained was compared with the simulated flow. The long‐term flow as low flow was also calculated, through runoff component analysis, to determine the hydraulic characteristics of the control point and to examine the runoff characteristics during the low flow water utilization seasons.The study results show that during the low flow period (between 2003 and 2005), the simulated flow (based on the SSARR model) approximated the long‐term flow (based on the runoff component analysis).The results, however, also show that the observed flow, according to the stage discharge curve formula developed by the Geum River Flood Control Office, was overestimated by about 10% up to 20% both during the normal water level and drought seasons, due to hydraulic factors caused by the spatial characteristics of Gongju point, a main control point. The results of the study reveal that the estimation of the flow must be corrected, and that such flow must be continuously monitored. Copyright © 2008 John Wiley & Sons, Ltd.
Ferritin and FasL (CD95L) mediate density dependent apoptosis in primary rat hepatocytes
Authors: Bresgen N. , Ohlenschläger I. , Wacht N. , Afazel S. , Ladurner G. , Eckl P.M. 
Published: August 2008

AbstractBased on a recent description of an apoptosis stimulating property for hepatocyte derived isoferritins, this investigation demonstrates that ferritin, released in vitro from hepatocytes substantially contributes to density dependent apoptosis in primary hepatocytes and is significantly (P ≤ 0.05) inhibited by anti‐H‐ferritin antibody rH02. Furthermore, total protein release and albumin secretion rapidly decline in a time and density dependent mode under serum‐free conditions, whereas ferritin secretion, which is upregulated at initial stages of primary culture is not affected by cell density. Supplementation with dexamethasone (DEX) or proliferative stimulation by epidermal growth factor (EGF) and insulin strongly suppresses density dependent apoptosis. Both regimens have previously been shown to inhibit isoferritin mediated apoptosis in hepatocytes, most likely by interrupting proapotitc mitochondrial signalling. Finally, FasL/Fas also participates in density dependent apoptosis, since apoptosis is significantly (P ≤ 0.005) reduced in high density cultures supplemented with an anti‐FasL antibody. This antibody has also been shown to neutralise ferritin mediated apoptosis in primary hepatocytes, suggesting a linkage of ferritin and Fas in density dependent apoptosis. In conclusion, ferritin contributes to apoptosis in primary hepatocytes in an autocrine, density dependent mode, involving Fas stimulation and proapoptotic mitochondrial signalling. With respect to liver physiology, these findings may indicate that ferritin plays a yet unrecognised role as an acute phase signalling molecule in early stages of tissue repair and liver regeneration, and may also be responsible for the limited ability to propagate human hepatocytes in culture and the limited expansion of donor cells in the recipient liver upon cell transplantation. J. Cell. Physiol. 217: 800–808, 2008. © 2008 Wiley‐Liss, Inc.
“APRIL hath put a spring of youth in everything”: Relevance of APRIL for survival
Authors: Kimberley Fiona C. , Hahne Michael , Medema Jan Paul 
Published: August 2008

AbstractA proliferation inducing ligand (APRIL or TALL‐2 and TRDL‐1) was first discovered as a cytokine over‐expressed in many transformed cells and with the capacity to stimulate proliferation. APRIL was shown to bind two different receptors of the TNF receptor superfamily: B cell maturation antigen (BCMA) and transmembrane activator and calcium modulator and cyclophilin ligand interactor (TACI), as well as heparan sulphate proteoglycans (HSPGs). APRIL has since been shown to play a physiological role in B cell biology, in particular the survival of plasma B cells in a specialized APRIL‐rich niche. However, aberrant expression of APRIL and the subsequent activation of pro‐survival pathways, is potentially the driving force for the survival of several B cell malignancies. APRIL has therefore become an important therapeutic target, but many questions regarding its mechanism of action still remain. It is for instance unclear what the exact physiological implications of the APRIL–HSPG interaction could be. Neither do we know the precise signals elicited by APRIL in normal or in malignant cells, and whether blocking these effects could provide real therapeutic gain in cancer patients. In this review we discuss the specific relevance of APRIL for cell survival, in terms of both its physiological role and its role in tumor biology, and highlight some of the key questions that will undoubtedly form the basis of future research in this field. J. Cell. Physiol. 218: 1–8, 2009. © 2008 Wiley‐Liss, Inc.