bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effect of unsaturated acyl chains on structural transformations in triacylglycerols
Authors: Mykhaylyk Oleksandr O. , Martin Christopher M. 
Published: January 2009

AbstractSimultaneous time‐resolved small‐angle and wide‐angle X‐ray scattering has been used in the study of the isothermal crystallization behavior, after quenching, of triacylglycerols (TAG) with 18 carbons in the hydrocarbon chains. Saturated, unsaturated TAG, their blends and mixed saturated/unsaturated TAG were studied. The mixed saturated/unsaturated TAG and their blends form an α2‐phase with a longitudinal packing different from two‐chain and three‐chain packings, which distinguishes them from the other fats. The unstable α2‐phase, observed at the initial stage of crystallization of mixed saturated/unsaturated TAG, is classified as a transient mesophase. Two dimeric units proposed for a structural model of the α2‐phase have been used to describe the structural organization of TAG molecules in the liquid state.
Unique Regioselective Binding of Permethylated β‐Cyclodextrin with Azobenzene Derivatives
Authors: Shi Jun , Guo Dong‐Sheng , Ding Fei , Liu Yu 
Published: January 2009

AbstractThe binding behavior of permethylated β‐cyclodextrin (PM‐β‐CD) upon complexation with 4‐hydroxyazobenzene (4‐HAB) and 4‐aminoazobenzene (4‐AAB) was investigated by X‐ray crystallography, circular dichroism, 2D NMR spectra, and isothermal titration calorimetry. In comparison to the reported β‐cyclodextrin (β‐CD) complexes with 4‐HAB and 4‐AAB, PM‐β‐CD complexes 3 and 4 present not only unique binding regioselectivity with azobenzene guests but also have distinct spatial arrangements, that is, β‐CDs arrange in a head‐to‐head manner, whereas PM‐β‐CDs arrange in a head‐to‐tail manner. The results obtained from circular dichroism and 2D NMR spectra indicate that the binding modes of complexes 3 and 4 in solution are in accordance with those in the solid state. Furthermore, the binding abilities and thermodynamic parameters of β‐CD and PM‐β‐CD upon complexation with azobenzene derivatives were discussed from the viewpoints of the flexibilities of the frameworks of the hosts and driving forces. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)
Asymmetric Lewis Acid Catalysis in Water: α‐Amino Acids as Effective Ligands in Aqueous Biphasic Catalytic Michael Additions
Authors: Aplander Karolina , Ding Rui , Krasavin Mikhail , Lindström U. Marcus , Wennerberg Johan 
Published: January 2009

AbstractThis article explores the potential of native α‐amino acids as chiral ligands in aqueous asymmetric Lewis acid catalysis, employing the C–C bond forming Michael addition as a model reaction. Some insights are provided regarding the details of Yb(OTf)3/α‐amino acid‐catalyzed Michael additions in water through new kinetic data as well as studies on how both yield and selectivity are influenced by variations in metal/ligand ratio, pH, temperature, and structure of the α‐amino acid. Through this investigation it was found that reaction conditions that require only 5 mol‐% of the Lewis acid, provides enantiomeric excesses of up to 79 % and is applicable to a wider range of donors and acceptors than previously demonstrated. Importantly, it was also demonstrated that the α‐amino acid complexed ytterbium catalyst might have potential for large‐scale applications as it displays not only large ligand accelerations, but also good solubility and stability in water. It can be recycled multiple times without appreciable loss of activity. The result is a promising example of a water‐compatible chiral Lewis acid.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)
Enantiocomplementary Chemoenzymatic Asymmetric Synthesis of (R)‐ and (S)‐Chromanemethanol
Authors: Fuchs Michael , Simeo Yolanda , Ueberbacher Barbara T. , Mautner Barbara , Netscher Thomas , Faber Kurt 
Published: January 2009

AbstractA non‐lipase‐based, enantiocomplementary chemoenzymatic route towards enantiopure (R)‐ and (S)‐chromanemethanol (12), which are the key building blocks for the synthesis of stereoisomerically pure α‐tocopherols, has been achieved by the biocatalytic resolution of a racemic 2,2‐disubstituted oxirane using an epoxide hydrolase and a halohydrin dehalogenase, which exhibit opposite enantiopreferences. The introduction of chirality at an early stage of the synthesis ensured a high efficiency, leading to total overall yields of 16 and 26 % for (R)‐ and (S)‐chromanemethanol (12), respectively.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)
1,2‐Diarylethanols by Alternative Regioselective Reductive Ring‐Opening of 2,3‐Diaryloxiranes
Authors: Di Blasio Nadia , Lopardo Maria Teresa , Lupattelli Paolo 
Published: January 2009

AbstractNon‐symmetrical trans‐2,3‐diaryloxiranes have been regioselectively opened by catalytic hydrogenation over Pd/C, NaBH4/Pd and [Cp2TiCl]/H2O. Although in the catalytic hydrogenation reactions the epoxides were mainly opened at the β‐carbon with respect to the substituted aryl ring in all cases, with the [Cp2TiCl]/H2O system the regioselectivity was affected by the electronic properties of the aryl residues, the epoxides being opened on the carbon bearing the most electron‐releasing or the least electron‐withdrawing group. With the NaBH4/Pd system different regioisomers were obtained depending on the substituents. Starting from enantioenriched epoxides, no loss of optical purity was observed in the alcohols formed.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)
Facile Approach to Natural or Non‐Natural Amino Acid Derivatives: Me3SiCl‐Promoted Coupling Reaction of Organozinc Compounds with N,O‐Acetals
Authors: Sakai Norio , Asano Junichi , Kawada Yuki , Konakahara Takeo 
Published: January 2009

AbstractWe have developed a Me3SiCl‐promoted coupling reaction of aryl‐ and alkylzinc compounds, in‐situ generated either by transmetalation of the corresponding organometallic reagents or by insertion of zinc metal into organic halides, with several N,O‐acetals, which leads to the preparation of a variety of natural and non‐natural amino acid derivatives. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)
CE‐MS analysis of heroin and its basic impurities using a charged polymer‐protected gold nanoparticle‐coated capillary
Authors: Zhang Zhengxiang , Yan Bo , Liu Kelin , Liao Yiping , Liu Huwei 
Published: January 2009

AbstractThe first application of charged polymer‐protected gold nanoparticles (Au NPs) as semi‐permanent capillary coating in CE‐MS was presented. Poly(diallyldimethylammonium chloride) (PDDA) was the only reducing and stabilizing agent for Au NPs preparation. Stable and repeatable coating with good tolerance to 0.1 M HCl, methanol, and ACN was obtained via a simple rinsing procedure. Au NPs enhanced the coating stability toward flushing by methanol, improved the run‐to‐run and capillary‐to‐capillary repeatabilities, and improved the separation efficiency of heroin and its basic impurities for tracing geographical origins of illicit samples. Baseline resolution of eight heroin‐related alkaloids was achieved on the PDDA‐protected Au NPs‐coated capillary under the optimum conditions: 120 mM ammonium acetate (pH 5.2) with addition of 13% methanol, separation temperature 20°C, applied voltage −20 kV, and capillary effective length 60.0 cm. CE‐MS analysis with run‐to‐run RSDs (n=5) of migration time in the range of 0.43–0.62% and RSDs (n=5) of peak area in the range of 1.49–4.68% was obtained. The established CE‐MS method would offer sensitive detection and confident identification of heroin and related compounds and provide an alternative to LC‐MS and GC‐MS for illicit drug control.
Formamide as an organic modifier in MEKC with SDS
Authors: Téllez Adolfo , Kenndler Ernst 
Published: January 2009

AbstractThe effect of formamide (FA) as a modifier on the retention in MEKC with SDS as the detergent was investigated. The mobility of a series of alkylphenones and of a zwitterionic fluorescent compound as a function of the FA and the SDS concentration was determined for this purpose. Buffering electrolyte was borate, pH 9.23, with total ionic strength of 50 mM. The dependence of the mobility on the FA content – up to 63% w/w – of the BGE (at 10 mM SDS) allows the conclusion that the micelles are destabilized, and the CMC is shifted to higher values. In the system containing 33% FA or more no micelles are present anymore, and the retention factors of all compounds tend to zero. In an MEKC system with 27% v/v FA the CMC of SDS is increased from 2.4 mM in the aqueous BGE with the same buffer composition to 9.7 mM, a behavior that is in contrast to electrolyte‐free FA–water systems. The partition constants of free analytes and the formation constants of the adduct between analyte and detergent monomer (assuming 1:1 stoichiometry) were derived from the dependence of the mobility on the SDS concentration. In addition, the involved equilibria were extended by that from the distribution of the analyte–monomer adduct between aqueous and micellar phase, and the according partition constants were derived as well. A selective change in the extent of partitioning was observed for the zwitterionic compound. In general, all binding constants were decreased upon addition of FA, though to a different extent. Although the binding constants of the analyte–monomer associate were only slightly influenced, the most pronounced decrease is found for their partitioning into the micelles.
Enantioseparation of nicotine alkaloids in cigarettes by CE using sulfated β‐CD as a chiral selector and a capillary coated with amino groups
Authors: Kodama Shuji , Morikawa Atsushi , Nakagomi Kazuya , Yamamoto Atsushi , Sato Atsushi , Suzuki Kentaro , Yamashita Tomohisa , Kemmei Tomoko , Taga Atsushi 
Published: January 2009

AbstractNicotine (NC) and its related compounds (cotinine (CN), nornicotine (NN), anatabine (AT) and anabasine (AB)) were simultaneously enantioseparated by CE using a capillary with amino groups and sulfated β‐CD as a chiral selector. The optimum running conditions were found to be 30 mM acetate buffer (pH 5.0) containing 8% sulfated β‐CD with an applied voltage of +15 kV at 30°C using direct detection at 260 nm. Using a capillary coated with amino groups, the EOF migrates toward the positive pole. However, when sulfated β‐CD was added to the BGE, it was found that the EOF migrated toward the negative pole due to ionic adsorption of sulfated β‐CD to amino groups on the capillary inner wall. All the cationic analytes migrated as anions, suggesting that they formed stable anionic complexes with sulfated β‐CD. With this system and a simple pretreatment with mini‐cartridges, NC alkaloids in five cigarette samples were enantioseparated. As a result, each of the compounds except for CN was detected. In the case of NC, only (S)‐NC was detected (more than 99.9%), but in the case of NN, AT and AB, the ratios of (S)‐isomer to total isomers were in the ranges 58–70, 81–85 and 59–65%, respectively. On the other hand, only NC was detected in cigarette smoke and the ratio of (S)‐ and (R)‐NCs was 96:4. The amounts of NC alkaloids in cigarettes suggest that the production of (R)‐NC resulted from racemization due to the high temperature/burning of the cigarette.
Can consumer sentiment and its components forecast Australian GDP and consumption?
Authors: Chua Chew Lian , Tsiaplias Sarantis 
Published: January 2009

AbstractThis paper examines whether the disaggregation of consumer sentiment data into its sub‐components improves the real‐time capacity to forecast GDP and consumption. A Bayesian error correction approach augmented with the consumer sentiment index and permutations of the consumer sentiment sub‐indices is used to evaluate forecasting power. The forecasts are benchmarked against both composite forecasts and forecasts from standard error correction models. Using Australian data, we find that consumer sentiment data increase the accuracy of GDP and consumption forecasts, with certain components of consumer sentiment consistently providing better forecasts than aggregate consumer sentiment data. Copyright © 2009 John Wiley & Sons, Ltd.
Postconcussion syndrome after minor head injury: Brain activation of working memory and attention
Authors: Smits Marion , Dippel Diederik W.J. , Houston Gavin C. , Wielopolski Piotr A. , Koudstaal Peter J. , Hunink M.G. Myriam , van der Lugt Aad 
Published: January 2009

AbstractAfter minor head injury (MHI) postconcussive symptoms (PCS) such as memory and attention deficits frequently occur. It has been hypothesised that PCS are caused by microstructural damage to the brain due to shearing injury, which is not detectable with conventional imaging, and may be responsible for a functional deficit. The purpose of this study was to correlate functional magnetic resonance imaging brain activation of working memory and selective attention with PCS. 21 MHI patients and 12 healthy controls were scanned at 3T. Stimulation paradigms were the n‐back and Counting Stroop tasks to engage working memory and selective attention, respectively. Functional data analysis consisted of random effects group analyses, correlating brain activation patterns with the severity of PCS as evaluated with the Rivermead postconcussion symptoms questionnaire. At minimal working memory load, activation was seen in patients with greater severity of PCS in the working memory network. With an increase of working memory load, increase of activation was more pronounced in patients with greater severity of PCS. At high and increased working memory load, activation associated with the severity of PCS was seen in the posterior parietal area, parahippocampal gyrus, and posterior cingulate gyrus. Activation related to selective attention processing was increased with greater severity of PCS. The increased activity in relation to working memory and attention, and the recruitment of brain areas outside the working memory network at high working memory load, may be considered a reflection of the brain's compensatory response to microstructural injury in patients with PCS. Hum Brain Mapp, 2009. © 2008 Wiley‐Liss, Inc.
Neural correlates of resolving uncertainty in driver's decision making
Authors: Callan Akiko M. , Osu Rieko , Yamagishi Yuya , Callan Daniel E. , Inoue Naomi 
Published: January 2009

AbstractNeural correlates of driving and of decision making have been investigated separately, but little is known about the underlying neural mechanisms of decision making in driving. Previous research discusses two types of decision making: reward‐weighted decision making and cost‐weighted decision making. There are many reward‐weighted decision making neuroimaging studies but there are few cost‐weighted studies. Considering that driving involves serious risk, it is assumed that decision making in driving is cost weighted. Therefore, neural substrates of cost‐weighted decision making can be assessed by investigation of driver's decision making. In this study, neural correlates of resolving uncertainty in driver's decision making were investigated. Turning right in left‐hand traffic at a signalized intersection was simulated by computer graphic animation based videos. When the driver's view was occluded by a big truck, the uncertainty of the oncoming traffic was resolved by an in‐car video assist system that presented the driver's occluded view. Resolving the uncertainty reduced activity in a distributed area including the amygdala and anterior cingulate. These results implicate the amygdala and anterior cingulate as serving a role in cost‐weighted decision making. Hum Brain Mapp 2009. © 2008 Wiley‐Liss, Inc.
Improved EEG source analysis using low‐resolution conductivity estimation in a four‐compartment finite element head model
Authors: Lew Seok , Wolters Carsten H. , Anwander Alfred , Makeig Scott , MacLeod Rob S. 
Published: January 2009

AbstractBioelectric source analysis in the human brain from scalp electroencephalography (EEG) signals is sensitive to geometry and conductivity properties of the different head tissues. We propose a low‐resolution conductivity estimation (LRCE) method using simulated annealing optimization on high‐resolution finite element models that individually optimizes a realistically shaped four‐layer volume conductor with regard to the brain and skull compartment conductivities. As input data, the method needs T1‐ and PD‐weighted magnetic resonance images for an improved modeling of the skull and the cerebrospinal fluid compartment and evoked potential data with high signal‐to‐noise ratio (SNR). Our simulation studies showed that for EEG data with realistic SNR, the LRCE method was able to simultaneously reconstruct both the brain and the skull conductivity together with the underlying dipole source and provided an improved source analysis result. We have also demonstrated the feasibility and applicability of the new method to simultaneously estimate brain and skull conductivity and a somatosensory source from measured tactile somatosensory‐evoked potentials of a human subject. Our results show the viability of an approach that computes its own conductivity values and thus reduces the dependence on assigning values from the literature and likely produces a more robust estimate of current sources. Using the LRCE method, the individually optimized four‐compartment volume conductor model can, in a second step, be used for the analysis of clinical or cognitive data acquired from the same subject. Hum Brain Mapp, 2009. © 2008 Wiley‐Liss, Inc.
Repetition suppression for performed hand gestures revealed by fMRI
Authors: de C. Hamilton Antonia F. , Grafton Scott T. 
Published: January 2009

AbstractThe functional components of the human motor system that are used to retrieve and execute simple intransitive hand gestures were identified with a repetition suppression (RS) paradigm. Participants performed movements with the right hand to text instructions in a rapid event related design with a pseudo‐random stimulus order. Brain areas associated with action retrieval were identified by comparing trials where an action was repeated to trials that involved a new action. Performance of a novel action, collapsed across individual actions, resulted in significantly greater activity in a left hemisphere predominant fronto‐parietal circuit involving inferior frontal gyrus and inferior parietal cortex (supramarginal gyrus). This is consistent with previous action retrieval tasks using go, no‐go paradigms and lesion studies of patients with apraxia that emphasize a role of these areas in action organization. In addition, RS effects were present in left primary sensorimotor cortex. These effects cannot be ascribed to kinematic differences, simple action related activity or differences of cognitive set. Significant RS effects for action retrieval could be identified with as little as 5 min of fMRI data and underscores the potential of using RS to characterize representational structure within the motor system. Hum Brain Mapp, 2009. © 2008 Wiley‐Liss, Inc.
Daily energy expenditure, physical activity, and weight loss in Parkinson's disease patients
Authors: Delikanaki‐Skaribas Evangelia , Trail Marilyn , Wong William Wai‐Lun , Lai Eugene C. 
Published: January 2009

AbstractPatients with Parkinson's disease (PD) commonly exhibit weight loss (WL) which investigators attribute to various factors, including elevated energy expenditure. We tested the hypothesis that daily energy expenditure (DEE) and its components, resting energy expenditure (REE) and physical activity (PA) energy expenditure (PAEE), are elevated in WL compared with weight stable (WS) PD patients. We measured DEE in 10 PD WL patients and 10 PD WS patients using doubly labeled water (DLW). PAEE was estimated with DLW, activity monitors, and activity questionnaires. REE was measured with indirect calorimetry. We evaluated energy intake (EI) with a patient's 3‐day food diary. Data was assessed employing SPSS, Spearman correlation coefficients, and Bland and Altman plots. There was no difference in DEE between the WL and WS groups measured with DLW. There were no differences in REE and EI between groups. DEE (r = 0.548, P < 0.05) and PAEE (r = 0.563, P < 0.01) are related with caloric intake. The WL group had higher PA than the WS group (P < 0.042) only when measured with wrist activity monitors. Results suggest that WL in PD patients cannot be fully explained by an increase in DEE. Large longitudinal studies to examine multiple relationships between variables might provide us with a better understanding of WL among PD patients. © 2008 Movement Disorders Society
Zonisamide for essential tremor: An evaluator‐blinded study
Authors: Handforth Adrian , Martin Fredricka C. , Kang Gail A. , Vanek Zeba 
Published: January 2009

AbstractIn this evaluator‐blinded open‐treatment trial, subjects with moderate/severe upper limb essential tremor were titrated to 300 mg/day zonisamide, or adjusted to a lesser dose if symptoms warranted, as monotherapy or as adjunct to stable antitremor medication, followed by a 12‐week extension phase. The primary efficacy outcome variables were blinded rater videotaped/drawing tremor score changes at the Treatment and Extension visits compared to Baseline, based on Fahn‐Tolosa‐Marin and Postural Tremor Scales. Subjects also rated Functional Disabilities. Primary outcomes showed reduced tremor scores at the Treatment (P < 0.00001, n = 25) and Extension (n = 16) visits, at mean doses of 252 and 225 mg/day, respectively. Subject ratings indicated 200 mg/day was superior to 100 mg/day, whereas 300 mg/day produced no additional benefit, but instead was associated with more adverse symptoms, most commonly somnolence, poor energy, imbalance, and altered taste. Future double‐blind placebo‐controlled trials are warranted. © 2008 Movement Disorders Society
Validity of the Cornell scale for depression in dementia in Parkinson's disease with and without cognitive impairment
Authors: Williams James R. , Marsh Laura 
Published: January 2009

AbstractValid tools are needed to assess depression across the spectrum of cognitive impairment in Parkinson's disease (PD). The validity of the Cornell scale for depression in dementia (CSDD) was tested in a PD sample with a range of cognitive impairment. Psychiatric diagnoses were established according to DSM‐IV‐TR. Receiver operating characteristic curves tested the discriminant validity of the CSDD compared to the clinical diagnoses of major and minor depression. The curve for symptomatic depression had an area under the curve of 0.82. For the cut‐off score ≥ 6, sensitivity was 0.83 and specificity was 0.73; for the cut‐off score ≥ 8, sensitivity was 0.75 and specificity was 0.82. There was no evidence for differential measurement with respect to cognitive impairment or any other demographic or clinical variables. This study suggests that the CSDD is a valid tool for identifying depressive disorders in patients with PD across a spectrum of cognitive impairment. © 2008 Movement Disorders Society
Haplotype analysis of the PARK 11 gene, GIGYF2, in sporadic Parkinson's disease
Authors: Sutherland Greg T. , Siebert Gerhard A. , Newman Jeremy R. B. , Silburn Peter A. , Boyle Richard S. , O'Sullivan John D. , Mellick George D. 
Published: January 2009

AbstractFamilial Parkinsonism (PARK) genes are strong candidates for conferring susceptibility to common forms of PD. However, most studies to date have provided little evidence that their common variants substantially influence disease risk. Recently, mutations were described in the gene, GIGYF2 (TNRC15), located at the PARK11 locus (2q37.1). Here, we use a haplotype tagging approach to examine common variation in the GIGYF2 gene and PD risk. PD cases (n = 568) and age and gender‐matched control subjects (n = 568) were recruited from three specialist movement disorder clinics in Brisbane (Australia) and the Australian electoral roll. Twelve tagging SNPs were assessed in all subjects and haplotype and genotype associations were explored. Overall our findings suggest that common genetic variants of GIGYF2 do not significantly affect sporadic PD risk in Australian Caucasians. © 2008 Movement Disorder Society