bluuebunny/crossref_metadata_2025_split huggingface dataset:
Insights into Intramolecular Trp and His Side‐Chain Orientation and Stereospecific π Interactions Surrounding Metal Centers: An Investigation Using Protein Metal‐Site Mimicry in Solution
Authors: Yang Chi Ming , Zhang Jie 
Published: July 2010

AbstractMetal‐binding scaffolds incorporating a Trp/His‐paired epitope are instrumental in giving novel insights into the physicochemical basis of functional and mechanistic versatility conferred by the Trp–His interplay at a metal site. Herein, by coupling biometal site mimicry and 1H and 13C NMR spectroscopy experiments, modular constructs EDTA‐(L‐Trp, L‐His) (EWH; EDTA=ethylenediamino tetraacetic acid) and DTPA‐(L‐Trp, L‐His) (DWH; DTPA=diethylenetriamino pentaacetic acid) were employed to dissect the static and transient physicochemical properties of hydrophobic/hydrophilic aromatic interactive modes surrounding biometal centers. The binding feature and identities of the stoichiometric metal‐bound complexes in solution were investigated by using 1H and 13C NMR spectroscopy, which facilitated a cross‐validation of the carboxylate, amide oxygen, and tertiary amino groups as the primary ligands and indole as the secondary ligand, with the imidazole (Im) N3 nitrogen being weakly bound to metals such as Ca2+ owing to a multivalency effect. Surrounding the metal centers, the stereospecific orientation of aromatic rings in the diastereoisomerism is interpreted with the Ca2+–EWH complex. With respect to perturbed Trp side‐chain rotamer heterogeneity, drastically restricted Trp side‐chain flexibility and thus a dynamically constrained rotamer interconversion due to π interactions is evident from the site‐selective 13C NMR spectroscopic signal broadening of the Trp indolyl C3 atom. Furthermore, effects of Trp side‐chain fluctuation on indole/Im orientation were the subject of a 2D NMR spectroscopy study by using the Ca2+‐bound state; a CH2(indolyl)/CH5(Im+) connectivity observed in the NOESY spectra captured direct evidence that the NH1 of the Ca2+–Im+ unit interacted with the pyrrole ring of the indole unit in Ca2+‐bound EWH but not in DWH, which is assignable to a moderately static, anomalous, T‐shaped, interplanar π+–π stacking alignment. Nevertheless, a comparative 13C NMR spectroscopy study of the two homologous scaffolds revealed that the overall response of the indole unit arises predominantly from global attractions between the indole ring and the entire positively charged first coordination sphere. The study thus demonstrates the coordination‐sphere/geometry dependence of the Trp/His side‐chain interplay, and established that π interactions allow 13C NMR spectroscopy to offer a new window for investigating Trp rotamer heterogeneity near metal‐binding centers.
A Chemical Strategy for the Relaxivity Enhancement of GdIII Chelates Anchored on Mesoporous Silica Nanoparticles
Authors: Carniato Fabio , Tei Lorenzo , Cossi Maurizio , Marchese Leonardo , Botta Mauro 
Published: July 2010

AbstractFunctionalised MCM‐41 mesoporous silica nanoparticles were used as carriers of GdIII complexes for the development of nanosized magnetic resonance imaging contrast agents. Three GdIII complexes based on the 1,4,7,10‐tetraazacyclododecane scaffold (DOTA; monoamide‐, DOTA‐ and DO3A‐like complexes) with distinct structural and magnetic properties were anchored on the silica nanoparticles functionalised with NH2 groups. The interaction between GdIII chelates and surface functional groups markedly influenced the relaxometric properties of the hybrid materials, and were deeply modified passing from ionic NH3+ to neutral amides. A complete study of the structural, textural and surface properties together with a full 1H relaxometric characterisation of these hybrid materials before and after surface modification was carried out. Particularly for the anionic complex 2 attached to MCM‐41, an impressive increase in relaxivity (r1p) was observed (from 20.3 to 37.8 mM−1 s−1, 86.2 % enhancement at 20 MHz and 310 K), mainly due to a threefold faster water exchange rate after acetylation of the surface NH3+ ions. This high r1p value, coupled with the large molar amount of grafted 2 onto the silica nanoparticles gives rise to a value of relaxivity per particle of 29 500 mM−1 s−1, which possibly allows it to be used in molecular imaging procedures. Smaller changes were observed for the hybrid materials based on neutral 1 and 3 complexes. In fact, whereas 1 shows a weak interaction with the surface and acetylation induced only some decrease of the local rotation, complex 3 appears to be involved in a strong interaction with surface silanols. This results in the displacement of a coordinated water molecule and in a decrease of the accessibility of the solvent to the metal centre, which is unaffected by the modification of ammonium ions to neutral amides.
Kinetic Isotope Effects in Asymmetric Reactions
Authors: Giagou Thomas , Meyer Matthew P. 
Published: July 2010

AbstractKinetic isotope effects are exquisitely sensitive probes of transition structure. As such, kinetic isotope effects offer a uniquely useful probe for the symmetry‐breaking process that is inherent to stereoselective reactions. In this Concept article, we explore the role of steric and electronic effects in stereocontrol, and we relate these concepts to recent studies carried out in our laboratory. We also explore the way in which kinetic isotope effects serve as useful points of contact with computational models of transition structures. Finally, we discuss future opportunities for kinetic isotope effects to play a role in asymmetric catalyst development.
Model Studies in Heterogeneous Catalysis
Authors: Freund H.‐J. 
Published: July 2010

AbstractI review a concept that models heterogeneous catalysis based on a surface‐science approach. It is shown that models catching part of the complexity of the real system, which is connected with the finite size of active components and the flexibility of the arrangement of atoms in the active component, play an important part in determining the activity and selectivity of the system. I have chosen several examples from our own laboratory to elaborate the details and will put those into perspective with respect to the literature. I will show that Pd nanoparticles in hydrogenation incorporate hydrogen, which turns out to be crucial for the actual hydrogenation step. Another example correlates the structure of vanadia monolayer catalysts with its reactivity in methanol oxidation. With a third example we address the question of charge on Au nanoparticles when anchored to an oxide surface, a problem heavily discussed in the literature. Further examples refer to ultrathin oxide film catalysts in which the oxide metal interface controls either the charge state of Au particles grown on the film, and, in a last example, the oxide film itself exhibits remarkable CO‐oxidation activity, which can be traced to a reactive intermediate structure of the ultrathin film.
On a TiNiSi‐Type Superstructure: Synthesis, Crystal and Electronic Structures of CaAgGe and Its Mn‐Substituted Derivative
Authors: Ponou Siméon 
Published: July 2010

AbstractThe compound CaAgGe and its Mn‐substituted derivative CaMn0.07Ag0.93Ge were synthesized by reaction of the element mixtures at high temperature. Their structures were refined from single‐crystal X‐ray diffraction data. CaAgGe crystallizes in the isomorphic (i3) superstructure of the TiNiSi type (CaCuGe type). The LMTO band structure calculations predicted the CaAgGe phase to be metallic. In addition, it appeared that the valence electron concentration is critical for the atomic ordering and the resulting superstructure. Thus, CaAgGe is one electron short per asymmetric unit, but a drastic narrowing of the electron shortage is achieved through the more complex atomic ordering in the supercell, relative to the simple TiNiSi type subcell. This results in the formation of {Ge2} dumbbells in the supercell, which ascribe greater electronic flexibility to the structure. Despite the fact that CaAgGe is not a Zintl phase in the strict definition as valence balanced intrinsic semiconductor, its structural aspects and transport properties can still be understood within the Zintl concept. The formal Zintl phase Ca3MnAg2Ge3 could be predicted from the theoretical calculations, but no significant phase width was observed experimentally in the substituted derivative Ca3Mn0.21Ag2.79Ge3.
Diffusion tensor imaging and white matter lesions at the subacute stage in mild traumatic brain injury with persistent neurobehavioral impairment
Authors: Messé Arnaud , Caplain Sophie , Paradot Gaëlle , Garrigue Delphine , Mineo Jean‐François , Soto Ares Gustavo , Ducreux Denis , Vignaud Frédéric , Rozec Gaëlle , Desal Hubert , Pélégrini‐Issac Mélanie , Montreuil Michèle , Benali Habib , Lehéricy Stéphane 
Published: July 2010

AbstractMild traumatic brain injury (mTBI) can induce long‐term behavioral and cognitive disorders. Although the exact origin of these mTBI‐related disorders is not known, they may be the consequence of diffuse axonal injury (DAI). Here, we investigated whether MRI at the subacute stage can detect lesions that are associated with poor functional outcome in mTBI by using anatomical images (T1) and diffusion tensor imaging (DTI). Twenty‐three patients with mTBI were investigated and compared with 23 healthy volunteers. All patients underwent an MRI investigation and clinical tests between 7 and 28 days (D15) and between 3 and 4 months (M3) after injury. Patients were divided in two groups of poor outcome (PO) and good outcome (GO), based on their complaints at M3. Groupwise differences in gray matter partial volume between PO patients, GO patients and controls were analyzed using Voxel‐Based Morphometry (VBM) from T1 data at D15. Differences in microstructural architecture were investigated using Tract‐Based Spatial Statistics (TBSS) and the diffusion images obtained from DTI data at D15. Permutation‐based non‐parametric testing was used to assess cluster significance at p < 0.05, corrected for multiple comparisons. Twelve GO patients and 11 PO patients were identified on the basis of their complaints. In PO patients, gray matter partial volume was significantly lower in several cortical and subcortical regions compared with controls, but did not differ from that of GO patients. No difference in diffusion variables was found between GO and controls. PO patients showed significantly higher mean diffusivity values than both controls and GO patients in the corpus callosum, the right anterior thalamic radiations and the superior longitudinal fasciculus, the inferior longitudinal fasciculus and the fronto‐occipital fasciculus bilaterally. In conclusion, PO patients differed from GO patients by the presence of diffusion changes in long association white matter fiber tracts but not by gray matter partial volume. These results suggest that DTI at the subacute stage may be a predictive marker of poor outcome in mTBI. Hum Brain Mapp, 2011. © 2010 Wiley‐Liss, Inc.
Estimating lifetime or episode‐of‐illness costs under censoring
Authors: Basu Anirban , Manning Willard G. 
Published: July 2010

AbstractMany analyses of healthcare costs involve use of data with varying periods of observation and right censoring of cases before death or at the end of the episode of illness. The prominence of observations with no expenditure for some short periods of observation and the extreme skewness typical of these data raise concerns about the robustness of estimators based on inverse probability weighting (IPW) with the survival from censoring probabilities. These estimators also cannot distinguish between the effects of covariates on survival and intensity of utilization, which jointly determine costs. In this paper, we propose a new estimator that extends the class of two‐part models to deal with random right censoring and for continuous death and censoring times. Our model also addresses issues about the time to death in these analyses and separates the survival effects from the intensity effects. Using simulations, we compare our proposed estimator to the inverse probability estimator, which shows bias when censoring is large and covariates affect survival. We find our estimator to be unbiased and also more efficient for these designs. We apply our method and compare it with the IPW method using data from the Medicare–SEER files on prostate cancer. Copyright © 2010 John Wiley & Sons, Ltd.
Multiple roles of cytochrome c oxidase in mammalian cells under action of red and IR‐A radiation
Authors: Karu Tiina I. 
Published: July 2010

AbstractThis article reviews the current knowledge in photobiology and photomedicine about the influence of monochromatic, quasimonochromatic, and bread‐band radiation of red‐to‐near infrared (IR‐A) part on solar spectrum upon mammalian cells and human skin. The role of cytochrome c oxidase as the photoacceptor and photosignal transducer is underlined and its photosensitivity at certain circumstances is discussed. The role of ATP as a critical signaling molecule is discussed. © 2010 IUBMB IUBMB Life, 62(8): 607–610, 2010.
The glycemic response is a personal attribute
Authors: Whelan William J. , Hollar Danielle , Agatston Arthur , Dodson Hannah J. , Tahal Dimitri S. 
Published: July 2010

AbstractThe Glycemic Index (GI) is a measure of the extent of the change in blood glucose content (glycemic response) following consumption of digestible carbohydrate, relative to a standard such as glucose. We have explored whether the reported GIs of foods are a sufficient guide to a person wishing to avoid large glycemic responses and thereby avoid hyperglycemia. For this purpose, volunteers carried out multiple tests of four foods, following overnight fasting, measuring the glycemic response over 2 H. The areas under the blood glucose/time curves (AUCs) were compared. Each food tester displayed individual, characteristic glycemic responses to each food, unrelated to any other tester's response. Wide variations (up to 5‐fold) were seen between the average AUCs for the same test by different testers. The absolute magnitudes of the glycemic responses are important for individuals trying to control blood sugar and/or body weight, but using published GI lists as a guide to control the glycemic response is not fully informative. This is because in calculating the GI, individual glycemic responses to glucose are normalized to 100. GI values are, therefore, relative and are not necessarily a reliable guide to the person's actual individual AUC when consuming a food. Without knowledge of the person's characteristic blood glucose responses, reliance only on the GI may be misleading. © 2010 IUBMB IUBMB Life, 62(8): 637–641, 2010.
The impact of fire on redistribution of soil organic matter on a mediterranean hillslope under maquia vegetation type
Authors: Novara A. , Gristina L. , Bodì M.B. , Cerdà A. 
Published: July 2010

AbstractSoil organic matter (SOM) changes affect the CO2 atmospheric levels and is a key factor on soil fertility and soil erodibility. Fire affects ecosystems and the soil properties due to heating and post‐fire soil erosion and degradation processes. In order to understand fire effects on soil organic carbon (SOC) balance research was undertaken on a fire‐prone ecosystem: the Mediterranean maquia. The spatial distribution of SOC was measured in a Burnt site 6 months after a wildfire and in a Control site. Samples were collected at two different depths (0–3 and 3–10 cm) and SOC was determined. The results show that 41·8 per cent of the SOC stock was lost. This is due to the removal of the burnt material by surface wash. No significant differences in SOC content were found for the subsurface samples between burnt and control plots. Those results show that ashes and charcoal are transported by runoff downslope and are subsequently deposited in the valley bottom and this is the key process that contributes the burial of SOC after a forest fire. SOC redistribution by water erosion is accelerated after forest fires and contribute to the degradation of soils located at the upper part of the hillslopes but causes the enrichment with SOM of the soils located at the valley bottom. Buried SOC in the bottoms valley terraces will contribute to the sequestration of carbon for longer. Conservation of abandoned terraces is a key policy to avoid land degradation and climate change. Copyright © 2010 John Wiley & Sons Ltd.
Who was the man who discovered the “Lewy bodies”?
Authors: Rodrigues e Silva Antonio M. , Geldsetzer Felix , Holdorff Bernd , Kielhorn Friedrich W. , Balzer‐Geldsetzer Monika , Oertel Wolfgang H. , Hurtig Howard , Dodel Richard 
Published: July 2010

AbstractIn 1912, Fritz Heinrich Lewy described neuronal inclusions in the brain of patients who had suffered from Paralysis agitans (i.e., Parkinson's disease). Later, these findings became the so‐called “Lewy bodies.” However, little is known about the man who made this discovery. Our aim was to investigate Lewy's private and professional life and to gather information for a detailed biography. We contacted over 100 archives, libraries, and museums in Germany, Poland, Switzerland, United Kingdom, and United States. Over 300 documents, publications, and photos were collected. Lewy was born in Berlin, Germany in 1885 and lived there until 1933. After his dismissal on racial grounds by the Nazis, Lewy emigrated to England in 1933 and to the United States of America in 1934, where he lived and worked until his death in 1950. This article gives a summary of Lewy's life and briefly presents his contribution to German and American neurology. © 2010 Movement Disorder Society
Altered pattern of motor cortical activation–inhibition during voluntary movements in Tourette syndrome
Authors: Franzkowiak Stephanie , Pollok Bettina , Biermann‐Ruben Katja , Südmeyer Martin , Paszek Jennifer , Jonas Melanie , Thomalla Götz , Bäumer Tobias , Orth Michael , Münchau Alexander , Schnitzler Alfons 
Published: July 2010

AbstractIn patients with Gilles de la Tourette syndrome (GTS) alterations of motor cortex (M1) excitability at rest have been evidenced. In contrast, there has so far been little research into changes of motor cortical reactivity during the time course of voluntary movements in GTS patients. The present study investigates neuromagnetic event‐related desynchronization (ERD) and event‐related synchronization (ERS) of bilateral M1 in 11 GTS patients and 11 healthy control subjects. ERD represents motor cortical activation, whereas ERS most likely indicates its inhibition. Subjects performed a self‐paced finger movement task while magnetoencephalography was used to record neuromagnetic activity. In GTS patients, ERD at beta frequency was significantly increased in the contralateral hemisphere before and during movements, whereas ERS following movement termination was increased in M1 ipsilateral. Ipsilateral ERS was inversely correlated with tic severity as determined by the Yale Global Tic Severity Rating Scale. The data of the present study support the hypothesis that during voluntary movements, motor cortical reactivity is pathologically altered in GTS patients. The observed pattern of increased activation (ERD) prior to and during movement execution followed by increased inhibition (ERS) after movement termination at beta frequency suggests abnormally increased motor cortical activation, possibly driving stronger inhibition. The stronger this inhibition is, the better symptoms appear to be controlled. © 2010 Movement Disorder Society
Juvenile levodopa‐responsive Parkinsonism with early orobuccolingual dyskinesias and cognitive impairment
Authors: Espay Alberto J. , Paviour Dominic C. , O'Sullivan John D. , Schmidt Robert E. , Revilla Fredy J. , Metman Leo Verhagen 
Published: July 2010

AbstractA 13‐year old girl presented with slowly progressive rest tremor of the hands, bradykinesia, and rigidity. The symptoms improved with dopaminergic medications, but severe drug‐induced dyskinesias developed early. She subsequently developed cognitive slowing and difficulty initiating saccadic eye movements. She went on to have deep brain stimulation surgery. Experts discuss the syndromal diagnosis and predict the underlying pathology. The pathological diagnosis is given and clinical learning points are considered. © 2010 Movement Disorder Society
The “imprisoned illness:” Motor tic disorder in Rainer Maria Rilke'sNotebooks of Malte Laurids Brigge
Authors: Cavanna Andrea Eugenio , Pattumelli Maria Grazia , Quarto Tiziana , Ali Fizzah , Rickards Hugh 
Published: July 2010

AbstractRainer Maria Rilke's novelThe Notebooks of Malte Laurids Briggecontains a reference of interest for the catalog of literary portrayals oftiqueurs. In this article, we report his description of a Parisian character displaying multiple motor tic symptoms, along with a brief commentary. © 2010 Movement Disorder Society
Neuroanatomical correlates of apathy in Parkinson's disease: A magnetic resonance imaging study using voxel‐based morphometry
Authors: Reijnders Jennifer S.A.M. , Scholtissen Bart , Weber Wim E.J. , Aalten Pauline , Verhey Frans R.J. , Leentjens Albert F.G. 
Published: July 2010

AbstractApathy is generally defined as a disorder of motivation and is considered one of the most common neuropsychiatric disturbances in Parkinson's disease (PD). Only few studies addressed the neuroanatomical correlates of apathy in PD. The aim of this article was to determine the structural correlates of apathy in PD patients. Fifty‐five PD patients underwent a neuropsychiatric and neuropsychological examination, and a 3 T magnetic resonance imaging scan was acquired. A voxel‐based multiple regression analysis was used to calculate correlation between gray matter density and severity measures of apathy. Apathy correlates with decreased cognitive functioning and more depressive symptoms but not with more severe motor symptoms. High apathy scores were correlated with low gray matter density values in a number of cortical brain areas: the bilateral precentral gyrus (BA 4, 6), the bilateral inferior parietal gyrus (BA 40), the bilateral inferior frontal gyrus (BA 44, 47), the bilateral insula (BA 13), the right (posterior) cingulate gyrus (BA 24, 30, 31), and the right precuneus (BA 31). Apathy in PD correlates with reduced gray matter density in a number of brain regions. The involvement of the cingulate gyrus and inferior frontal gyrus is in line with the results of earlier studies addressing apathy in patients with Alzheimer's disease or depressive disorder. Further studies addressing the pathogenesis of apathy are needed. © 2010 Movement Disorder Society.
On meteorological droughts in tropical Pacific Islands: time‐series analysis of observed rainfall using Fiji as a case study
Authors: Deo Ravinesh C. 
Published: July 2010

AbstractAnalysis of historical droughts was undertaken by converting observed monthly rainfall over the period 1949–2008 to the Standardized Precipitation Index (SPI). The modified Mann–Kendall test applied on monthly rainfall showed statistically significant downward trends at significance level α = 0.01. The Sen's Slope, estimated from the time‐series, revealed statistically significant decreases in annual rainfall ranging from ∼13 to 47 mm year−1. Based on the SPI, drought duration and severity was non‐uniform across stations over the 60 year period. The strongest impacted stations were located in western and northern Fiji where rainfall deficiency for the period 1969–1988 led to a dramatic increase in moderate and severe droughts. The return periods of annual rainfall were much longer at these stations relative to those in outer‐lying islands. While rainfall increased over the period 1989–2008, the actual amounts did not exceed 1949–1968 totals, confirming a net shift towards drier conditions since the 1950s. This study has demonstrated that SPI can be a useful tool for diagnosis and monitoring meteorological droughts in tropical Pacific islands. Copyright © 2010 Royal Meteorological Society