bluuebunny/crossref_metadata_2025_split huggingface dataset:
[(NHC)(NHCewg)RuCl2(CHPh)] Complexes with Modified NHCewg Ligands for Efficient Ring‐Closing Metathesis Leading to Tetrasubstituted Olefins
Authors: Sashuk Volodymyr , Peeck Lars H. , Plenio Herbert 
Published: February 2010

AbstractImidazolium salts (NHCewg⋅HCl) with electronically variable substituents in the 4,5‐position (H,H or Cl,Cl or H,NO2 or CN,CN) and sterically variable substituents in the 1,3‐position (Me,Me or Et,Et or iPr,iPr or Me,iPr) were synthesized and converted into the respective [AgI(NHC)ewg] complexes. The reactions of [(NHC)RuCl2(CHPh)(py)2] with the [AgI(NHCewg)] complexes provide the respective [(NHC)(NHCewg)RuCl2(CHPh)] complexes in excellent yields. The catalytic activity of such complexes in ring‐closing metathesis (RCM) reactions leading to tetrasubstituted olefins was studied. To obtain quantitative substrate conversion, catalyst loadings of 0.2–0.5 mol % at 80 °C in toluene are sufficient. The complex with the best catalytic activity in such RCM reactions and the fastest initiation rate has an NHCewg group with 1,3‐Me,iPr and 4,5‐Cl,Cl substituents and can be synthesized in 95 % isolated yield from the ruthenium precursor. To learn which one of the two NHC ligands acts as the leaving group in olefin metathesis reactions two complexes, [(FL‐NHC)(NHCewg)RuCl2(CHPh)] and [(FL‐NHCewg)(NHC)RuCl2(CHPh)], with a dansyl fluorophore (FL)‐tagged electron‐rich NHC ligand (FL‐NHC) and an electron‐deficient NHC ligand (FL‐NHCewg) were prepared. The fluorescence of the dansyl fluorophore is quenched as long as it is in close vicinity to ruthenium, but increases strongly upon dissociation of the respective fluorophore‐tagged ligand. In this manner, it was shown for ring‐opening metathesis ploymerization (ROMP) reactions at room temperature that the NHCewg ligand normally acts as the leaving group, whereas the other NHC ligand remains ligated to ruthenium.
VCD study of α‐methylbenzyl amine derivatives: Detection of the unchanged chiral motif
Authors: Merten Christian , Amkreutz Marc , Hartwig Andreas 
Published: February 2010

AbstractChiral α‐methylbenzyl amine is a well known and often used chiral auxiliary, e.g., in the resolution of racemates or asymmetric catalysis. In this work, α‐methylbenzyl amine and its derivatives N,α‐dimethylbenzyl amine, N,N,α‐trimethylbenzyl amine, and bis[α‐methylbenzyl] amine were investigated by vibrational circular dichroism (VCD) spectroscopy and density functional theory (DFT). For all compounds, stable low energy conformers were obtained by the DFT calculations and based on those, the theoretical vibrational absorption (VA) and VCD spectra were calculated and compared with experimental spectra. Hence, the absolute configurations and conformational preferences were determined. A qualitative comparison of all the experimental VCD spectra of the investigated chiral molecules supported by the calculated ones is given which clearly shows similarities between the spectra of the different chiral amines. These can be assigned to vibrations of the unchanged chiral center. Chirality 2010. © 2010 Wiley‐Liss, Inc.
Vibrational circular dichroism of 3‐(trifluoroacetyl)‐camphor and its interaction with chiral amines
Authors: Merten Christian , Jalkanen Karl J. , Weiss Volker C. , Hartwig Andreas 
Published: February 2010

AbstractVibrational circular dichroism (VCD) spectroscopy and density functional theory (DFT) calculations are used to investigate the keto–enol equilibrium of 3‐(trifluoroacetyl)‐camphor (TFC) and to study the interaction of TFC with chiral amines in deuterated Chloroform. It is shown that the VCD spectra of the enol‐ and keto forms of TFC can clearly be distinguished and that the enol form is favored. By deprotonation of the TFC enol with chiral amines, no indication of a mutual diasteriomeric influence on the VCD spectra induced by transfer of stereochemical information between the chiral ionic species is found, neither experimentally nor theoretically. Chirality 2010. © 2010 Wiley‐Liss, Inc.
Zusammenhang zwischen Trocknungsverlauf und Gutsdicke bei wasserfeuchten, plattenförmigen Gütern Teil 1: Trocknungsexperimente und Modellierung der Trocknungskinetik
Authors: Gierecki Ł. , Kind M. 
Published: February 2010

AbstractIn dieser Arbeit wurden Trocknungsverlaufskurven für ein breites Spektrum an plattenförmigen, porösen Feststoffen unterschiedlicher Gutsdicken mit einem Versuchsprallstrahltrockner aufgenommen. Die gemessenen Trocknungsverlaufskurven und der Einfluss der Gutsdicke konnten mit einem geeigneten Modell, das den flüssigen Stofftransport im Gut berücksichtigt, gut wiedergeben werden. In einem folgenden Teil 2 der Veröffentlichung werden die Möglichkeiten für eine einfache Umrechnung der Trocknungszeiten auf eine andere Plattendicke anhand der gemessenen Trocknungsverlaufskurven diskutiert.
Racial differences in the perception of lung cancer
Authors: Lathan Christopher S. , Okechukwu Cassandra. , Drake Bettina F. , Bennett Gary G. 
Published: February 2010

AbstractBACKGROUND:Racial disparities in lung cancer have been described well in the literature; however, little is known about perceptions of lung cancer in the general population and whether these perceptions differ by race.METHODS:Data were obtained from the 2005 Health Information National Trends Survey (HINTS) survey. The authors used a sample design of random digit dialing of listed telephone exchanges in the United States. Complete interviews were conducted with 5491 adults, including 1872 respondents who were assigned to receive questions pertaining to lung cancer. All analyses were conducted on this subset of respondents. A statistical software program was used to calculate chi‐square tests and to perform logistic regression analyses that would model racial differences in perceptions of lung cancer. All estimates were weighted to be nationally representative of the US population; a jack‐knife weighting method was used for parameter estimation.RESULTS:Black patients and white patients shared many of the same beliefs about lung cancer mortality, and etiology. African Americans were more likely than whites 1) to agree that it is hard to follow recommendations about preventing lung cancer (odds ratio [OR], 2.05; 95% confidence interval [CI], 1.19‐3.53), 2) to avoid an evaluation for lung cancer for fear that they have the disease (OR, 3.32; 95% CI, 1.84‐5.98), and 3) to believe that patients with lung cancer would have pain or other symptoms before diagnosis (OR, 2.20; 95% CI, 1.27‐3.79).CONCLUSIONS:African Americans were more likely to hold beliefs about lung cancer that could interfere with prevention and treatment. Cancer 2010. © 2010 American Cancer Society.
Two members of the SIBLING family of proteins, DSPP and BSP, may predict the transition of oral epithelial dysplasia to oral squamous cell carcinoma
Authors: Ogbureke Kalu U. E. , Abdelsayed Rafik A. , Kushner Harvey , Li Li , Fisher Larry W. 
Published: February 2010

AbstractBACKGROUND:Patients with oral premalignant lesions (OPL) present with oral squamous cell carcinomas (OSCC) at a much higher rate than the general population. There are currently no useful markers that indicate specifically which OPLs are most likely to progress. Three small integrin binding ligands N‐linked glycoprotein (SIBLING) family proteins, bone sialoprotein (BSP), osteopontin (OPN), and dentin sialophosphoprotein (DSPP), have been shown to be up‐regulated in many cancers, including OSCC. The status of SIBLING expression in OPLs and their correlation to transition to oral cancer are unknown.METHODS:Sixty archival surgical biopsies of dysplastic OPLs were evaluated by immunohistochemistry for expression of BSP, DSPP, and OPN and correlated with local transformation to OSCC at sites adjacent to surgically removed dysplastic OPL.RESULTS:The OPL patient population was representative of previous studies with 20% progressing to OSCC, and no correlation between degree of dysplasia and progression. Eighty‐seven percent were positive for at least 1 SIBLING protein. OPN expression had no correlation with progression. The BSP+/DSPP− expression pattern however correlated with decreased transformation to OSCC (point prevalence = 0%; 95% confidence interval [CI], 0‐20.6), whereas the BSP−/DSPP+ pattern was associated with more frequent progression (point prevalence = 77.8%; 95%CI, 47.8‐95.4). Incrementally higher expression scores (0 to 3) of BSP and DSPP were also associated with increased predictive values (odds ratio, 25.53; 95% CI, 2.14‐304.7 and 10.13; 95% CI, 2.0‐50.0, respectively, for each increment).CONCLUSIONS:BSP and DSPP are excellent candidate markers for successful OPL surgical intervention and may be predictors of OPL‐OSCC progression. Cancer 2010. © 2010 American Cancer Society.
Cumulative evaluation of a quantitative immunochemical fecal occult blood test to determine its optimal clinical use
Authors: Rozen Paul , Comaneshter Doron , Levi Zohar , Hazazi Rachel , Vilkin Alex , Maoz Eran , Birkenfeld Shlomo , Niv Yaron 
Published: February 2010

AbstractBACKGROUND:Quantified, human hemoglobin (Hb)‐specific, immunochemical fecal occult blood test (IFOBT) measurements are now used for colorectal cancer (CRC) screening. The objective was to evaluate sensitivity and specificity for CRC and advanced adenomatous polyps (APs) by the fecal Hb threshold used to determine a positive test and the number of IFOBTs prepared per test, so as to determine the least number of colonoscopies required to detect a neoplasm.METHODS:Cumulative data were analyzed from a prospective cross‐sectional double‐blind study of 1682 consecutive, ambulatory, nonbleeding colonoscopy patients who volunteered for IFOBTs, most of above average risk, from 3 ambulatory‐endoscopy centers. Fecal Hb was measured in 3 samples and analyzed by an automated instrument, and the highest result ≥50 ng Hb/mL of buffer was related to findings.RESULTS:Colonoscopy identified CRC in 20 patients and advanced APs in 129. Sensitivity for either was best when any of 3 tests had ≥50 ng Hb/mL of buffer; sensitivity was 61.1% (95% confidence interval [CI], 53.2‐68.9), and specificity was 87.8% (95% CI, 86.2‐89.4). Positive tests identified 100% of CRCs and 55% of advanced APs every 3.1 colonoscopies. Sensitivity of a single test at the commonly used 100‐ng Hb/mL threshold was lower at 31.5% (95% CI, 24.1‐39.0) (P<.001), but specificity was higher at 96.4% (95% CI, 95.5‐97.3) (P<.001). Positive tests identified 65% of CRCs and 26.4% of advanced APs every 2.2 colonoscopies.CONCLUSIONS:The fecal Hb cutoff chosen by the screener and the number of samples collected per patient determine sensitivity and specificity for CRC/advanced AP; these factors determine the number of colonoscopies needed for positive tests and neoplasia yield. This information provides guidelines for IFOBT screening. Limitations are 1‐time screening and most examinees not being at average risk for CRC. Cancer 2010. © 2010 American Cancer Society.
Model Studies on CO Oxidation Catalyst Systems: Titania and Gold Nanoparticles
Authors: Christmann Klaus , Schwede Sebastian , Schubert Susanne , Kudernatsch Wilhelmine 
Published: February 2010

AbstractThe peculiar catalytic activity of Au‐supported titanium dioxide surfaces in the CO oxidation reaction has been a focus of interest for more than twenty years. Herein, recent data concerning preparation and structural characterisation of planar catalyst model systems consisting of single‐crystalline titania and/or gold nanoparticles deposited thereon is presented and reviewed. We first expand on the deposition and growth of TiO2 films on selected metal host surfaces and then consider the deposition of Au nanoparticles on these surfaces, including information on their geometric and electronic structures. The second issue is the interaction of these materials with carbon monoxide (one of the essential ingredients of the CO oxidation reaction) which serves as a probe molecule and monitor of the chemical activity of the model catalyst samples. Concerted efforts relating the structural and chemical properties of the respective binary materials (titania support plus deposited gold) can help to tackle and finally resolve the still open problems concerning the high activity of Au–TiO2 catalysts in the CO oxidation reaction.
Self‐Assembly of Photosynthetic Membranes
Authors: Hsin Jen , Chandler Danielle E. , Gumbart James , Harrison Christopher B. , Sener Melih , Strumpfer Johan , Schulten Klaus 
Published: February 2010

AbstractBacterial photosynthetic membranes, also known as chromatophores, are tightly packed with integral membrane proteins that work together to carry out photosynthesis. Chromatophores display a wide range of cellular morphologies; spherical, tubular, and lamellar chromatophores have all been observed in different bacterial species, or with different protein constituents. Through recent computational modeling and simulation, it has been demonstrated that the light‐harvesting complexes abundant in chromatophores induce local membrane curvature via multiple mechanisms. These protein complexes assemble to generate a global curvature and sculpt the chromatophores into various cellular‐scale architectures.
Supramolecular Organization and Chiral Resolution of p‐Terphenyl‐m‐Dicarbonitrile on the Ag(111) Surface
Authors: Marschall Matthias , Reichert Joachim , Seufert Knud , Auwärter Willi , Klappenberger Florian , Weber‐Bargioni Alexander , Klyatskaya Svetlana , Zoppellaro Giorgio , Nefedov Alexei , Strunskus Thomas , Wöll Christof , Ruben Mario , Barth Johannes V. 
Published: February 2010

AbstractThe supramolecular organization and layer formation of the non‐linear, prochiral molecule [1, 1′;4′,1′′]‐terphenyl‐3,3“‐dicarbonitrile adsorbed on the Ag(111) surface is investigated by scanning tunneling microscopy (STM) and near‐edge X‐ray absorption fine‐structure spectroscopy (NEXAFS). Upon two‐dimensional confinement the molecules are deconvoluted in three stereoisomers, that is, two mirror‐symmetric trans‐ and one cis‐species. STM measurements reveal large and regular islands following room temperature deposition, whereby NEXAFS confirms a flat adsorption geometry with the electronic π‐system parallel to the surface plane. The ordering within the expressed supramolecular arrays reflects a substrate templating effect, steric constraints and the operation of weak lateral interactions mainly originating from the carbonitrile endgroups. High‐resolution data at room temperature reveal enantiormorphic characteristics of the molecular packing schemes in different domains of the arrays, indicative of chiral resolution during the 2D molecular self‐assembly process. At submonolayer coverage supramolecular islands coexist with a disordered fluid phase of highly mobile molecules. Following thermal quenching (down to 6 K) we find extended supramolecular ribbons stabilised again by attractive and directional noncovalent interactions, the formation of which reflects a chiral resolution of trans‐species.
New dynamic ID authentication scheme using smart cards
Authors: Tsai Jia‐Lun , Wu Tzong‐Chen , Tsai Kuo‐Yu 
Published: February 2010

AbstractRecently, Yoonet al. and Wanget al. independently proposed a dynamic ID authentication scheme and claimed that their schemes can withstand the risk of ID‐theft, and several attacks. In this paper, we first demonstrate that both of the proposed schemes cannot achieve the security requirement for user anonymity and resist an impersonation attack yet. Then, we shall propose a new dynamic ID authentication scheme to overcome the above security weaknesses. We formally analyzed our proposed scheme with the BAN‐logic and shown that it can withstand the several possible attacks. Copyright © 2010 John Wiley & Sons, Ltd.
The role of BDNF and its receptors in depression and antidepressant drug action: Reactivation of developmental plasticity
Authors: Castrén Eero , Rantamäki Tomi 
Published: February 2010

AbstractRecent evidence suggests that neuronal plasticity plays an important role in the recovery from depression. Antidepressant drugs and electroconvulsive shock treatment increase the expression of several molecules, which are associated with neuronal plasticity, in particular the neurotrophin BDNF and its receptor TrkB. Furthermore, these treatments increase neurogenesis and synaptic numbers in several brain areas. Conversely, depression, at least in its severe form, is associated with reduced volumes of the hippocampus and prefrontal cortex and in at least some cases these neurodegenerative signs can be attenuated by successful treatment. Such observations suggest a central role for neuronal plasticity in depression and the antidepressant effect, and also implicate BDNF signaling as a mediator of this plasticity. The antidepressant fluoxetine can reactivate developmental‐like neuronal plasticity in the adult visual cortex, which, under appropriate environmental guidance, leads to the rewiring of a developmentally dysfunctional neural network. These observations suggest that the simple form of the neurotrophic hypothesis of depression, namely, that deficient levels of neurotrophic support underlies mood disorders and increases in these neurotrophic factors to normal levels brings about mood recovery, may not sufficiently explain the complex process of recovery from depression. This review discusses recent data on the role of BDNF and its receptors in depression and the antidepressant response and suggests a model whereby the effects of antidepressant treatments could be explained by a reactivation of activity‐dependent and BDNF‐mediated cortical plasticity, which in turn leads to the adjustment of neuronal networks to better adapt to environmental challenges. © 2010 Wiley Periodicals, Inc. Develop Neurobiol 2010
Nerve growth factor as a paradigm of neurotrophins related to Alzheimer's disease
Authors: Calissano P. , Matrone C. , Amadoro G. 
Published: February 2010

AbstractConverging lines of evidence on the possible connection between NGF signaling and Alzheimer's diseases (AD) are unraveling new facets which could depict this neurotrophin (NTF) in a more central role. AD animal models have provided evidence that a shortage of NGF supply may induce an AD‐like syndrome. In vitro experiments, moreover, are delineating a possible temporal and causal link between APP amiloydogenic processing and altered post‐translational tau modifications. After NGF signaling interruption, the pivotal upstream players of the amyloid cascade (APP, β‐secretase, and active form of γ‐secretase) are up‐regulated, leading to an increased production of amyloid β peptide (Aβ) and to its intracellular aggregation in molecular species of different sizes. Contextually, the Aβ released pool generates an autocrine toxic loop in the same healthy neurons. At the same time tau protein undergoes anomalous, GSKβ‐mediated, phosphorylation at specific pathogenetic sites (Ser262 and Thr 231), caspase(s) and calpain‐ I‐ mediated truncation, detachment from microtubules with consequent cytoskeleton collapse and axonal transport impairment. All these events are inhibited when the amyloidogenic processing is reduced by β and γ secretase inhibitors or anti‐Aβ antibodies and appear to be causally correlated to TrkA, p75CTF, Aβ, and PS1 molecular association in an Aβ‐mediated fashion. In this scenario, the so‐called trophic action exerted by NGF (and possibly also by other neurotrophins) in these targets neurons is actually the result of an anti‐amyloidogenic activity. © 2010 Wiley Periodicals, Inc. Develop Neurobiol 2010
Neurotrophin receptors: Old friends with new partners
Authors: Schecterson Leslayann C. , Bothwell Mark 
Published: February 2010

AbstractNeurotrophins are important regulators of embryonic development and adult function of most populations of neurons in vertebrate nervous systems. This signaling system regulates many diverse activities, including survival, axon outgrowth, and synaptic plasticity. In mammals, neurotrophin action is mediated by four receptors, p75NTR, TrkA, TrkB, and TrkC. Although early studies viewed these receptors as solitary agents in the cells outer membrane, recent discoveries reveal that the cell outer membrane is a crowded and highly interactive neighborhood. Neurotrophin receptors partner with a diverse array of membrane proteins, dramatically expanding their functional repertoire. This review will focus on some of the most recent discoveries concerning the promiscuous partnering of neurotrophin receptors. © 2010 Wiley Periodicals, Inc. Develop Neurobiol 2010
Understanding proneurotrophin actions: Recent advances and challenges
Authors: Teng Kenneth K. , Felice Sarah , Kim Taeho , Hempstead Barbara L. 
Published: February 2010

AbstractNeurotrophins are initially synthesized as larger precursors (proneurotrophins), which undergo proteolytic cleavage to yield mature forms. Although the functions of the mature neurotrophins have been well established during neural development and in the adult nervous system, roles for the proneurotrophins in developmental and injury‐induced cell death, as well as in synaptic plasticity, have only recently been appreciated. Interestingly, both mature neurotrophins and proneurotrophins utilize dual‐receptor complexes to mediate their actions. The mature neurotrophin coreceptors consist of the Trk receptor tyrosine kinases and p75NTR, wherein Trk transduces survival and differentiative signaling, and p75NTR modulates the affinity and selectivity of Trk activation. On the other hand, proneurotrophins engage p75NTR and the structurally distinct coreceptor sortilin, to initiate p75NTR‐dependent signal transduction cascade. Although the specificity of mature neurotrophins vs. proneurotrophins actions is due in part to the formation of distinct coreceptor complexes, a number of recent studies highlight how different p75NTR‐mediated cellular actions are modulated. Here, we review emerging evidence for a novel transmembrane mechanism for ligand‐specific p75NTR activation and several mechanisms by which p75NTR‐dependent apoptotic and nonapoptotic responses can be selective activated. © 2010 Wiley Periodicals, Inc. Develop Neurobiol 2010
Assembly and activation of neurotrophic factor receptor complexes
Authors: Simi Anastasia , Ibáñez Carlos F. 
Published: February 2010

AbstractNeurotrophic factors play important roles in the development and function of both neuronal and glial elements of the central and peripheral nervous systems. Their functional diversity is in part based on their ability to interact with alternative complexes of receptor molecules. This review focuses on our current understanding of the mechanisms that govern the assembly and activation of neurotrophic factor receptor complexes. The realization that many, if not the majority, of these complexes exist in a preassembled form at the plasma membrane has forced the revision of classical ligand‐mediated oligomerization models, and led to the discovery of novel mechanisms of receptor activation and generation of signaling diversity which are likely to be shared by many different classes of receptors. © 2010 Wiley Periodicals, Inc. Develop Neurobiol 2010