bluuebunny/crossref_metadata_2025 huggingface dataset:
Temperature‐Responsive Polymer/Carbon Nanotube Hybrids: Smart Conductive Nanocomposite Films for Modulating the Bioelectrocatalysis of NADH
Authors: Zhao Xin , Liu Yang , Lu Jin , Zhou Jianhua , Li Jinghong
Published: February 2012

A temperature‐sensitive polymer/carbon nanotube interface with switchable bioelectrocatalytic capability was fabricated by self‐assembly of poly(N‐isopropylacrylamide)‐grafted multiwalled carbon nanotubes (MWNT‐g‐PNIPAm) onto the PNIPAm‐modified substrate. Electron microscopy and electrochemical measurements revealed that these fairly thick (>6 μm) and highly porous nanocomposite films exhibited high conductivity and electrocatalytic activity. The morphological transitions in both the tethered PNIPAm chains on a substrate and those polymers wrapping around the MWNT surface resulted in the opening, closing, or tuning of its permeability, and simultaneously an electron‐transfer process took place through the channels formed in the nanostructure in response to temperature change. By combining the good electron‐transfer and electrochemical catalysis capabilities, the large surface area, and good biocompatibility of MWNTs with the responsive features of PNIPAm, reversible temperature‐controlled bioelectrocatalysis of 1,4‐dihydro‐β‐nicotinamide adenine dinucleotide with improved sensitivity has been demonstrated by cyclic voltammetry and electrochemical impedance spectroscopy measurements. The mechanism behind this approach was studied by Raman spectroscopy, in situ attenuated total reflection FTIR spectroscopy, and contact angle measurements. The results also suggested that the synergetic or cooperative interactions of PNIPAm with MWNTs gave rise not only to an increase in surface wettability, but also to the enhancement of the interfacial thermoresponsive behavior. This bioelectrocatalytic “smart” system has potential applications in the design of biosensors and biofuel cells with externally controlled activity. Furthermore, this concept might be proposed for biomimetics, interfacial engineering, bioelectronic devices, and so forth.
Pair‐copula constructions for non‐Gaussian DAG models
Authors: Bauer Alexander , Czado Claudia , Klein Thomas
Published: February 2012

We propose a new type of multivariate statistical model that permits non‐Gaussian distributions as well as the inclusion of conditional independence assumptions specified by a directed acyclic graph. These models feature a specific factorisation of the likelihood that is based on pair‐copula constructions and hence involves only univariate distributions and bivariate copulas, of which some may be conditional. We demonstrate maximum‐likelihood estimation of the parameters of such models and compare them to various competing models from the literature. A simulation study investigates the effects of model misspecification and highlights the need for non‐Gaussian conditional independence models. The proposed methods are finally applied to modeling financial return data.The Canadian Journal of Statistics40: 86–109; 2012 © 2012 Statistical Society of Canada
Truncated regular vines in high dimensions with application to financial data
Authors: Brechmann E. C. , Czado C. , Aas K.
Published: February 2012

Using only bivariate copulas as building blocks, regular vine copulas constitute a flexible class of high‐dimensional dependency models. However, the flexibility comes along with an exponentially increasing complexity in larger dimensions. In order to counteract this problem, we propose using statistical model selection techniques to either truncate or simplify a regular vine copula. As a special case, we consider the simplification of a canonical vine copula using a multivariate copula as previously treated by Heinen & Valdesogo (2009) and Valdesogo (2009). We validate the proposed approaches by extensive simulation studies and use them to investigate a 19‐dimensional financial data set of Norwegian and international market variables.The Canadian Journal of Statistics40: 68–85; 2012 © 2012 Statistical Society of Canada
Optimization of multigrid based elliptic solver for large scale simulations in the FLASH code
Authors: Daley Christopher , Vanella Marcos , Dubey Anshu , Weide Klaus , Balaras Elias
Published: February 2012

FLASH is a multiphysics multiscale adaptive mesh refinement (AMR) code originally designed for simulation of reactive flows often found in Astrophysics. With its wide user base and flexible applications configuration capability, FLASH has a dual task of maintaining scalability and portability in all its solvers. The scalability of fully explicit solvers in the code is tied very closely to that of the underlying mesh. Others such as the Poisson solver based on a multigrid method have more complex scaling behavior. Multigrid methods suffer from processor starvation and dominating communication costs at coarser grids with increase in the number of processors. In this paper, we propose a combination of uniform grid mesh with AMR mesh, and the merger of two different sets of solvers to overcome the scalability limitation of the Poisson solver in FLASH. The principal challenge in the proposed merger is the efficiency of the communication algorithm to map the mesh back and forth between uniform grid and AMR. We present two different parallel mapping algorithms and also discuss results from performance studies of the two implementations. Copyright © 2012 John Wiley & Sons, Ltd.
Conformations of Serine in Aqueous Solutions as Revealed by Vibrational Circular Dichroism
Authors: Zhu Peiyang , Yang Guochun , Poopari Mohammad Reza , Bie Zhi , Xu Yunjie
Published: February 2012

Vibrational circular dichroism (VCD) spectroscopy is utilized to reveal the detailed conformational distributions of the dominant serine species in aqueous solutions under three representative pH conditions of 1.0, 5.7, and 13.0, together with vibrational absorption (VA) spectroscopy, density functional theory (DFT), and molecular dynamics simulation. The experimental VA and VCD spectra of serine in H2O and D2O in the fingerprint region under three pH values are obtained. DFT calculations at the B3LYP/6‐311++G(d,p) level are carried out for the protonated, zwitterionic, and deprotonated serine species. The lowest‐energy conformers of all three species are identified and their corresponding VA and VCD spectra simulated. A comparison between the gas‐phase simulations and the experimental VA and VCD spectra suggests that one or two of the most stable conformers of each species contribute predominantly to the observed data, although some discrepancies are noted. To account for the solvent effects, both the polarizable continuum model and the explicit solvation model are considered. Hydrogen‐bonded protonated, zwitterionic, and deprotonated serine–(water)6clusters are constructed based on radial distribution function analyses and molecular dynamics snapshots. Geometry optimization and VA and VCD simulations are performed for these clusters at the B3LYP/6‐311++G(d,p) level. Inclusion of the explicit water molecules is found to improve the agreement between theory and experiment noticeably in all three cases, thus enabling conclusive conformational distribution analyses of serine in aqueous solutions directly.
Interpersonal Psychotherapy: Past, Present and Future
Authors: Markowitz John C. , Weissman Myrna M.
Published: February 2012

The authors briefly describe the origins, theory, and development of interpersonal psychotherapy: its roots in clinical outcome research, its spread from major depression to other psychiatric disorders and its increasing dissemination as an empirically validated clinical intervention included in treatment guidelines. They attempt to forecast research, organizational and training issues the growing interpersonal psychotherapy community may face in the future. Copyright © 2012 John Wiley & Sons, Ltd.

Key Practitioner Message

Multiple randomized controlled trials have shown that IPT effectively treats mood disorders, bulimia, and possibly other disorders in multiple randomized controlled trials.

Time‐limited treatment.

Focuses on the relationship between mood and social circumstance.

Improves social functioning while relieving symptoms.

Builds social support, a crucial factor in many psychiatric disorders.
The Role of the News Media in Influencing Corporate Environmental Sustainable Development: An Alternative Methodology to Assess Stakeholder Engagement
Authors: Haddock‐Fraser Janet
Published: February 2012

This paper investigates how UK newsprint media represent corporate environmental sustainable development activities, and whether they focus on particular sectors or companies with greater market visibility. This builds on, and looks to explain, previous findings that such companies are more active environmental reporters than their counterparts. It presents a novel approach, using content analysis of news media reporting, to implicitly measure consumer opinion ‐ an alternative to the more usual directed‐survey techniques. The implications of this research are substantial, providing an alternative method for academics and corporations to assess the extent to which the market is informed of, and interested in – in this case ‐ environmental performance, without the need for, or to supplement, costly and often inconsistent attitudinal surveys. Use of this approach could bring substantial benefits to corporate and public policy research approaches, providing a means of measuring enduring societal attitudes – whether for particular segments, target markets or nations. Copyright © 2012 John Wiley & Sons, Ltd and ERP Environment.
Functional pathway analysis in acute myeloid leukemia using single cell network profiling assay: Effect of specimen source (bone marrow or peripheral blood) on assay readouts
Authors: Cesano Alessandra , Rosen David B. , O'Meara Pat , Putta Santosh , Gayko Urte , Spellmeyer David C. , Cripe Larry D. , Sun Zhuoxin , Uno Hajime , Litzow Mark R. , Tallman Martin S. , Paietta Elisabeth
Published: February 2012

Background:

Single cell network profiling (SCNP) is used to simultaneously measure the effects of modulators on signaling networks at the single cell level. SCNP‐based biomarker assays predictive of response to induction therapy and relapse risk in acute myeloid leukemia (AML) patients are being developed. Such assays have typically used bone marrow (BM) as the sample source of blasts. Because circulating peripheral blasts are detectable in ∼65% of AML patients and peripheral blood (PB) sampling is less invasive than BM sampling, this study was performed to assess the effect of sample source on AML blasts signaling as measured in SCNP assay.

Methods:

SCNP using multiparametric flow cytometry was used to evaluate the activation state of intracellular signaling molecules in leukemic blasts under basal conditions and after treatment with modulators in 46 pairs of BM mononuclear cells/PB mononuclear cells. The relationship between readouts of modulated intracellular proteins (“nodes”) was measured using linear regression, Bland‐Altman method, and Lin's concordance correlation coefficient.

Results:

The majority (156/161) of signaling nodes show strong correlations between paired PB and BM samples independently from the statistical method used. Notable exceptions were two PB samples with almost undetectable levels of circulating blasts compared with paired BM samples.

Conclusions:

Our results demonstrate that specimen source (BM or PB) does not significantly affect proteomic signaling in patients with AML and circulating blasts. The ability to use PB as a sample source will facilitate the monitoring of cellular signaling effects following administration of targeted therapies and at time points when BM aspirates are not clinically justifiable. © 2012 International Clinical Cytometry Society
Contemporary and historical evolutionary processes interact to shape patterns of within‐lake phenotypic divergences in polyphenic pumpkinseed sunfish,Lepomis gibbosus
Authors: Weese Dylan J. , Ferguson Moira M. , Robinson Beren W.
Published: February 2012

Historical and contemporary evolutionary processes can both contribute to patterns of phenotypic variation among populations of a species. Recent studies are revealing how interactions between historical and contemporary processes better explain observed patterns of phenotypic divergence than either process alone. Here, we investigate the roles of evolutionary history and adaptation to current environmental conditions in structuring phenotypic variation among polyphenic populations of sunfish inhabiting 12 postglacial lakes in eastern North America. The pumpkinseed sunfish polyphenism includes sympatric ecomorphs specialized for littoral or pelagic lake habitats. First, we use population genetic methods to test the evolutionary independence of within‐lake phenotypic divergences of ecomorphs and to describe patterns of genetic structure among lake populations that clustered into three geographical groupings. We then used multivariate analysis of covariance (MANCOVA) to partition body shape variation (quantified with geometric morphometrics) among the effects of evolutionary history (reflecting phenotypic variation among genetic clusters), the shared phenotypic response of all populations to alternate habitats within lakes (reflecting adaptation to contemporary conditions), and unique phenotypic responses to habitats within lakes nested within genetic clusters. All effects had a significant influence on body form, but the effects of history and the interaction between history and contemporary habitat were larger than contemporary processes in structuring phenotypic variation. This highlights how divergence can be better understood against a known backdrop of evolutionary history.
Uncertainty analysis of vegetation distribution in the northern high latitudes during the 21st century with a dynamic vegetation model
Authors: Jiang Yueyang , Zhuang Qianlai , Schaphoff Sibyll , Sitch Stephen , Sokolov Andrei , Kicklighter David , Melillo Jerry
Published: February 2012

This study aims to assess how high‐latitude vegetation may respond under various climate scenarios during the 21st century with a focus on analyzing model parameters induced uncertainty and how this uncertainty compares to the uncertainty induced by various climates. The analysis was based on a set of 10,000 Monte Carlo ensemble Lund‐Potsdam‐Jena (LPJ) simulations for the northern high latitudes (45oN and polewards) for the period 1900–2100. The LPJ Dynamic Global Vegetation Model (LPJ‐DGVM) was run under contemporary and future climates from four Special Report Emission Scenarios (SRES), A1FI, A2, B1, and B2, based on the Hadley Centre General Circulation Model (GCM), and six climate scenarios, X901M, X902L, X903H, X904M, X905L, and X906H from the Integrated Global System Model (IGSM) at the Massachusetts Institute of Technology (MIT). In the current dynamic vegetation model, some parameters are more important than others in determining the vegetation distribution. Parameters that control plant carbon uptake and light‐use efficiency have the predominant influence on the vegetation distribution of both woody and herbaceous plant functional types. The relative importance of different parameters varies temporally and spatially and is influenced by climate inputs. In addition to climate, these parameters play an important role in determining the vegetation distribution in the region. The parameter‐based uncertainties contribute most to the total uncertainty. The current warming conditions lead to a complexity of vegetation responses in the region. Temperate trees will be more sensitive to climate variability, compared with boreal forest trees and C3 perennial grasses. This sensitivity would result in a unanimous northward greenness migration due to anomalous warming in the northern high latitudes. Temporally, boreal needleleaved evergreen plants are projected to decline considerably, and a large portion of C3 perennial grass is projected to disappear by the end of the 21st century. In contrast, the area of temperate trees would increase, especially under the most extreme A1FI scenario. As the warming continues, the northward greenness expansion in the Arctic region could continue.
Beltlike V2O3@C Core–Shell‐Structured Composite: Design, Preparation, Characterization, Phase Transition, and Improvement of Electrochemical Properties of V2O3
Authors: Zhang Yifu , Fan Meijuan , Liu Xinghai , Huang Chi , Li Houbin
Published: February 2012

A beltlike V2O3@C core–shell‐structured composite was successfully synthesized by thermal treatment with the precursor V3O7·H2O@C composite under an inert atmosphere. The phase, composition, structure, and morphology of the as‐obtained samples were confirmed by XRD, elemental analysis, FTIR, energy‐dispersive X‐ray spectroscopy (EDS), X‐ray photoelectron spectroscopy (XPS), IR Raman, SEM, and TEM measurements. The process of the formation of V2O3@C is briefly discussed. The carbon coated onto the surface of V2O3 is disordered, and V2O3 keeps the original morphology of V3O7·H2O. V2O3@C has an average length that ranges from 0.4 to 5.2 μm, a width of about 80–170 nm, and an average thickness of the shells of about 15.6 nm. The possible formation mechanism of V2O3@C is proposed as follows: the reaction undergoes a solid‐state reaction by the interface reaction between V3O7 cores and carbon shells. It was found that the V2O3@C composite possesses the same phase‐transition properties as V2O3, which could expand the possible applications of materials related to V2O3 in the future. Furthermore, a V2O3 sphere, a V2O3 nanobelt, and the beltlike V2O3@C composite were explored as cathode materials for application in lithium‐ion batteries. The beltlike V2O3@C composite electrode exhibited the best electrochemical properties among them, thereby achieving our aim of improving the electrochemical properties of V2O3.
Ionic liquid‐based dispersive liquid–liquid microextraction with back‐extraction coupled with capillary electrophoresis to determine phenolic compounds
Authors: Zhou Caihong , Tong Shanshan , Chang Yunxia , Jia Qiong , Zhou Weihong
Published: February 2012

Ionic liquid (IL) based dispersive liquid–liquid microextraction (DLLME) with back‐extraction coupled with capillary electrophoresis ultraviolet detection was developed to determine four phenolic compounds (bisphenol‐A, β‐naphthol, α‐naphthol, 2, 4‐dichlorophenol) in aqueous cosmetics. The developed method was used to preconcentrate and clean up the four phenolic compounds including two steps. The analytes were transferred into room temperature ionic liquid (1‐octyl‐3‐methylimidazolium hexafluorophosphate, [C8MIM][PF6]) rich‐phase in the first step. In the second step, the analytes were back‐extracted into the alkaline aqueous phase. The effects of extraction parameters, such as type and volume of extraction solvent, type and volume of disperser, extraction and centrifugal time, sample pH, salt addition, and concentration and volume of NaOH in back‐extraction were investigated. Under the optimal experimental conditions, the preconcentration factors were 60.1 for bisphenol‐A, 52.7 for β‐naphthol, 49.2 for α‐naphthol, and 18.0 for 2, 4‐dichlorophenol. The limits of detection for bisphenol‐A, β‐naphthol, α‐naphthol and 2, 4‐dichlorophenol were 5, 5, 8, and 100 ng mL−1, respectively. Four kinds of aqueous cosmetics including toner, soften lotion, make‐up remover, and perfume were analyzed and yielded recoveries ranging from 81.6% to 119.4%. The main advantages of the proposed method are quick, easy, cheap, and effective.
Innovative CO2 separation of biogas by polymer resins: Operation of a continuous lab‐scale plant
Authors: Raab Katharina , Lamprecht Martina , Brechtel Kevin , Scheffknecht Günter
Published: February 2012

Upgrading biogas allows for the injection of biomethane into the natural gas grid and thus a decentralized use. Since the currently available techniques have a high energy demand, there is a high potential to improve biogas upgrading. Innovative CO2 separation of biogas by the use of polymer resins can reduce the energy demand, the capital expenditure, and the operational costs. In this study, we show the ability of polymer resin to selectively adsorb CO2. Desorption tests showed the potential for continuous use of the resin. In a continuous lab‐scale plant, numerous variations of process parameters were carried out and optimization possibilities were demonstrated. Methane purity up to 98% was achieved. The favorable estimated energy demand indicates the great potential of the demonstrated improved process.
The use of novel biomarkers to determine dietary mercury accumulation in nestling waterbirds
Authors: Clarkson Charles E. , Erwin R. Michael , Riscassi Ami
Published: February 2012

Mercury (Hg) depuration into growing feathers is a well-studied phenomenon in waterbirds. Although the kinetics of Hg excretion in relation to molt and diet has been studied extensively, the relationship between the individual nutritional condition of nestlings and dietary Hg accumulation has not been investigated. In the present study, a body-condition index (BCI) and nutritional condition index (NCI) for nestlings of two waterbird species occupying different trophic positions on the aquatic food web were determined and used to predict Hg accumulation through diet. Candidate models consisting of these indices and nestling age were compared using Akaike's information criterion corrected for small sample sizes. For both species, the top-performing model contained the sole parameter of nutritional condition index (NCI). The relationship between Hg and NCI was stronger in the species foraging higher on the trophic web, which experienced higher rates of Hg depuration into feathers. Models containing BCI could not be discounted (AICc < 2) for one of the species and the utility of this index is discussed. Environ. Toxicol. Chem. 2012; 31: 1143–1148. © 2012 SETAC
Responses of microbial community from northern Gulf of Mexico sandy sediments following exposure to deepwater horizon crude oil
Authors: Horel Agota , Mortazavi Behzad , Sobecky Patricia A.
Published: February 2012

In the present study, microbial community responses to exposure to unweathered Macondo Well crude oil and conventional diesel in a sandy beach environment were determined. Biodegradation was assessed in mesocosm experiments with differing fuel amounts (2,000 and 4,000 mg/kg) and with or without inorganic nutrient amendment. Carbon dioxide production was measured daily for 42 d. Aerobic alkane, total hydrocarbon, and polycyclic aromatic hydrocarbon (PAH) degraders were enumerated in treated and control mesocosms and changes in their abundances were measured weekly. Hydrocarbon mineralization occurred in all treatments. In the inorganic nutrient-amended treatments, the degradation rates were 2.31 and 2.00 times greater in the 2,000 mg/kg diesel and crude oil treatments, respectively, and 3.52 (diesel) and 4.14 (crude) times higher for the fuel types at the 4,000 mg/kg fuel concentrations compared to unamended treatments. Microbial lag phases were short (<3 d) and alkane and total hydrocarbon degrader numbers increased by five orders of magnitude compared to the uncontaminated treatments within 7 d in most treatments. Hydrocarbon degrader numbers in diesel and in crude oil treatments were similar; however, the PAH degraders were more abundant in the crude oil relative to diesel treatment. These findings indicate that hydrocarbon degradation by extant microbial populations in the northern Gulf of Mexico sandy beach environments can be stimulated and enhanced by inorganic nutrient addition. Environ. Toxicol. Chem. 2012; 31: 1004–1011. © 2012 SETAC
Functional connectivity‐based identification of subdivisions of the basal ganglia and thalamus using multilevel independent component analysis of resting state fMRI
Authors: Kim Dae‐Jin , Park Bumhee , Park Hae‐Jeong
Published: February 2012

This study aimed to identify subunits of the basal ganglia and thalamus and to investigate the functional connectivity among these anatomically segregated subdivisions and the cerebral cortex in healthy subjects. For this purpose, we introduced multilevel independent component analysis (ICA) of the resting‐state functional magnetic resonance imaging (fMRI). After applying ICA to the whole brain gray matter, we applied second‐level ICA restrictively to the basal ganglia and the thalamus area to identify discrete functional subunits of those regions. As a result, the basal ganglia and the thalamus were parcelled into 31 functional subdivisions according to their temporal activity patterns. The extracted parcels showed functional network connectivity between hemispheres, between subdivisions of the basal ganglia and thalamus, and between the extracted subdivisions and cerebral functional components. Grossly, these findings correspond to cortico‐striato‐thalamo‐cortical circuits in the brain. This study also showed the utility of multilevel ICA of resting state fMRI in brain network research. Hum Brain Mapp, 2013. © 2012 Wiley Perodicals, Inc.
Adaptive changes in the neuromagnetic response of the primary and association somatosensory areas following repetitive tactile hand stimulation in humans
Authors: Popescu Elena Anda , Barlow Steven M. , Venkatesan Lalit , Wang Jingyan , Popescu Mihai
Published: February 2012

Cortical adaptation in the primary somatosensory cortex (SI) has been probed using different stimulation modalities and recording techniques, in both human and animal studies. In contrast, considerably less knowledge has been gained about the adaptation profiles in other areas of the cortical somatosensory network. Using magnetoencephalography (MEG), we examined the patterns of short‐term adaptation for evoked responses in SI and somatosensory association areas during tactile stimulation applied to the glabrous skin of the hand. Cutaneous stimuli were delivered as trains of serial pulses with a constant frequency of 2 Hz and 4 Hz in separate runs, and a constant inter‐train interval of 5 s. The unilateral stimuli elicited transient responses to the serial pulses in the train, with several response components that were separated by independent component analysis. Subsequent source reconstruction techniques identified regional generators in the contralateral SI and somatosensory association areas in the posterior parietal cortex (PPC). Activity in the bilateral secondary somatosensory cortex (i.e., SII/PV) was also identified, although less consistently across subjects. The dynamics of the evoked activity in each area and the frequency‐dependent adaptation effects were assessed from the changes in the relative amplitude of serial responses in each train. We show that the adaptation profiles in SI and PPC areas can be quantitatively characterized from neuromagnetic recordings using tactile stimulation, with the sensitivity to repetitive stimulation increasing from SI to PPC. A similar approach for SII/PV has proven less straightforward, potentially due to the tendency of these areas to respond selectively to certain stimuli. Hum Brain Mapp, 2013. © 2012 Wiley Perodicals, Inc.
Resting state cortical electroencephalographic rhythms are related to gray matter volume in subjects with mild cognitive impairment and Alzheimer's disease
Authors: Babiloni Claudio , Carducci Filippo , Lizio Roberta , Vecchio Fabrizio , Baglieri Annalisa , Bernardini Silvia , Cavedo Enrica , Bozzao Alessandro , Buttinelli Carla , Esposito Fabrizio , Giubilei Franco , Guizzaro Antonio , Marino Silvia , Montella Patrizia , Quattrocchi Carlo C. , Redolfi Alberto , Soricelli Andrea , Tedeschi Gioacchino , Ferri Raffaele , Rossi‐Fedele Giancarlo , Ursini Francesca , Scrascia Federica , Vernieri Fabrizio , Pedersen Torleif Jan , Hardemark Hans‐Goran , Rossini Paolo M. , Frisoni Giovanni B.
Published: February 2012

Cortical gray matter volume and resting state cortical electroencephalographic rhythms are typically abnormal in subjects with amnesic mild cognitive impairment (MCI) and Alzheimer's disease (AD). Here we tested the hypothesis that in amnesic MCI and AD subjects, abnormalities of EEG rhythms are a functional reflection of cortical atrophy across the disease. Eyes‐closed resting state EEG data were recorded in 57 healthy elderly (Nold), 102 amnesic MCI, and 108 AD patients. Cortical gray matter volume was indexed by magnetic resonance imaging recorded in the MCI and AD subjects according to Alzheimer's disease neuroimaging initiative project (http://www.adni‐info.org/). EEG rhythms of interest were delta (2–4 Hz), theta (4–8 Hz), alpha1 (8–10.5 Hz), alpha2 (10.5–13 Hz), beta1 (13–20 Hz), beta2 (20–30 Hz), and gamma (30–40 Hz). These rhythms were indexed by LORETA. Compared with the Nold, the MCI showed a decrease in amplitude of alpha 1 sources. With respect to the Nold and MCI, the AD showed an amplitude increase of delta sources, along with a strong amplitude reduction of alpha 1 sources. In the MCI and AD subjects as a whole group, the lower the cortical gray matter volume, the higher the delta sources, the lower the alpha 1 sources. The better the score to cognitive tests the higher the gray matter volume, the lower the pathological delta sources, and the higher the alpha sources. These results suggest that in amnesic MCI and AD subjects, abnormalities of resting state cortical EEG rhythms are not epiphenomena but are strictly related to neurodegeneration (atrophy of cortical gray matter) and cognition. Hum Brain Mapp, 2013. © 2012 Wiley Periodicals, Inc.
Prefrontal dopaminergic receptor abnormalities and executive functions in Parkinson's disease
Authors: Ko Ji Hyun , Antonelli Francesca , Monchi Oury , Ray Nicola , Rusjan Pablo , Houle Sylvain , Lang Anthony E. , Christopher Leigh , Strafella Antonio P.
Published: February 2012

The main pattern of cognitive impairments seen in early to moderate stages of Parkinson's disease (PD) includes deficits of executive functions. These nonmotor complications have a significant impact on the quality of life and day‐to‐day activities of PD patients and are not effectively managed by current therapies, a problem which is almost certainly due to the fact that the disease extends beyond the nigrostriatal system. To investigate the role of extrastriatal dopamine in executive function in PD, PD patients and a control group were studied with positron‐emission‐tomography using a high‐affinity dopamine D2/D3 receptor tracer, [11C]FLB‐457. All participants were scanned twice while performing an executive task and a control task. Patients were off medication for at least 12 h. The imaging analysis revealed that parkinsonian patients had lower [11C]FLB‐457 binding than control group independently of task conditions across different brain regions. Cognitive assessment measures were positively correlated with [11C]FLB‐457 binding in the bilateral dorsolateral prefrontal cortex and anterior cingulate cortex only in control group, but not in PD patients. Within the control group, during the executive task (as compared to control task), there was evidence of reduced [11C]FLB‐457 binding (indicative of increased dopamine release) in the right orbitofrontal cortex. In contrast, PD patients did not show any reduction in binding during the executive task (as compared with control task). These findings suggest that PD patients present significant abnormalities in extrastriatal dopamine associated with executive processing. These observations provide important insights on the pathophysiology of cognitive dysfunction in PD. Hum Brain Mapp, 2013. © 2012 Wiley Periodicals, Inc.
The dynamics of change in striatal activity following updating training
Authors: Kühn Simone , Schmiedek Florian , Noack Hannes , Wenger Elisabeth , Bodammer Nils C. , Lindenberger Ulman , Lövden Martin
Published: February 2012

Increases in striatal activity have been suggested to mediate training‐related improvements in working‐memory ability. We investigated the temporal dynamics of changes in task‐related brain activity following training of working memory. Participants in an experimental group and an active control group, trained on easier tasks of a constant difficulty in shorter sessions than the experimental group, were measured before, after about 1 week, and after more than 50 days of training. In the experimental group an initial increase of working‐memory related activity in the functionally defined right striatum and anatomically defined right and left putamen was followed by decreases, resulting in an inverted u‐shape function that relates activity to training over time. Activity increases in the striatum developed slower in the active control group, observed at the second posttest after more than 50 days of training. In the functionally defined left striatum, initial activity increases were maintained after more extensive training and the pattern was similar for the two groups. These results shed new light on the relation between activity in the striatum (especially the putamen) and the effects of working memory training, and illustrate the importance of multiple measurements for interpreting effects of training on regional brain activity. Hum Brain Mapp, 2013. © 2012 Wiley Periodicals, Inc.
Practical application of product design method robust to disturbances
Authors: Mrugalska Beata , Kawecka‐Endler Aleksandra
Published: February 2012

Contemporary designed and manufactured products should meet a wide range of client requirements and expectations regarding quality for conditions of use in a life cycle. Therefore, design methods, which enable an optimal choice of product parameters by decreasing product sensivity to occurrence of some disturbances in a manufacturing process, become more and more significant in industrial practice. Such a behavior probably allows getting the lowest quality loss while keeping planned production costs. In this article, a new method of products design robust to disturbances exsisting in a technological process is presented. The application of mathematical modeling and methods of parameter estimation enabled formulating an approach in which parameters and acceptable tolerance of manufacturing product parameters are calculated. The efficiency of the proposed method was verified in the machine‐building industry with the example of designing parameters of a brushless direct current motor. © 2010 Wiley Periodicals, Inc.
Data‐based analysis of bivariate copula tail dependence for drought duration and severity
Authors: Lee T. , Modarres R. , Ouarda T. B. M. J.
Published: February 2012

In recent decades, copula functions have been applied in bivariate drought duration and severity frequency analysis. Among several potential copulas, Clayton has been mostly used in drought analysis. In this research, we studied the influence of the tail shape of various copula functions (i.e. Gumbel, Frank, Clayton and Gaussian) on drought bivariate frequency analysis. The appropriateness of Clayton copula for the characterization of drought characteristics is also investigated. Drought data are extracted from standardized precipitation index time series for four stations in Canada (La Tuque and Grande Prairie) and Iran (Anzali and Zahedan). Both duration and severity data sets are positively skewed. Different marginal distributions were first fitted to drought duration and severity data. The gamma and exponential distributions were selected for drought duration and severity, respectively, according to the positive skewness and Kolmogorov–Smirnov test. The results of copula modelling show that the Clayton copula function is not an appropriate choice for the used data sets in the current study and does not give more drought risk information than an independent model for which the duration and severity dependence is not significant. The reason is that the dependence of two variables in the upper tail of Clayton copula is very weak and similar to the independent case, whereas the observed data in the transformed domain of cumulative density function show high association in the upper tail. Instead, the Frank and Gumbel copula functions show better performance than Clayton function for drought bivariate frequency analysis. Copyright © 2012 John Wiley & Sons, Ltd.
The hydrogeomorphic influences on alluvial gully erosion along the Mitchell River fluvial megafan
Authors: Shellberg J. G. , Brooks A. P. , Spencer J. , Ward D.
Published: February 2012

Hydrogeomorphic processes influencing alluvial gully erosion were evaluated at multiple spatial and temporal scales across the Mitchell River fluvial megafan in tropical Queensland, Australia. Longitudinal changes in floodplain inundation were quantified using river gauge data, local stage recorders and HEC‐RAS modelling based on LiDAR topographic data. Intra‐ and interannual gully scarp retreat rates were measured using daily time‐lapse photographs and annual GPS surveys. Erosion was analysed in response to different water sources and associated erosion processes across the floodplain perirheic zone, including direct rainfall, infiltration‐excess runoff, soil‐water seepage, river backwater and overbank flood inundation. The frequency of river flood inundation of alluvial gullies changed longitudinally according to river incision and confinement. Near the top of the megafan, flood water was contained within the macrochannel up to the 100‐year recurrence interval, but river backwater still partially inundated adjacent gullies eroding into Pleistocene alluvium. In downstream Holocene floodplains, inundation of alluvial gullies occurred beyond the 2‐ to 5‐year recurrence interval and contributed significantly to total annual erosion. However, most gully scarp retreat at all sites was driven by direct rainfall and infiltration‐excess runoff, with the 24‐h rainfall total being the most predictive variable. The remaining variability can be explained by seasonal vegetative conditions, complex cycles of soil wetting and drying, tension crack development, near‐surface pore‐water pressure, soil block undermining from spalling and overland flow, and soil property heterogeneity. Implications for grazing management impacts on soil surface and perennial grass conditions include effects on direct rainfall erosion, water infiltration, runoff volume, water concentration along tracks, and the resistance of highly dispersible soils to gully initiation or propagation under intense tropical rainfall. Copyright © 2012 John Wiley & Sons, Ltd.
Synthesis of Planar Chiral Carbazole Derivatives Bearing a [2.2]Paracyclophane Skeleton
Authors: Lennartz Petra , Raabe Gerhard , Bolm Carsten
Published: February 2012

The synthesis of planar chiral carbazoles bearing a [2.2]paracyclophane backbone is described. Starting from readily available 4‐bromo[2.2]paracyclophane planar chiral carbazoles are obtained in a two‐step synthesis by Pd‐catalyzed CN cross‐coupling and subsequent oxidative cyclization.
Aryl[2.2]paracyclophane‐Based Chiral Regioisomeric Analogs of Salicyl Aldehyde: Novel Sources for Construction of Phenoxy‐Imine Ligands
Authors: Zhuravsky Roman P. , Danilova Tatiana I. , Antonov Dmitrii Yu. , Sergeeva Elena V. , Starikova Zoya A. , Godovikov Ivan A. , Il'in Michail M. , Rozenberg Valeria I.
Published: February 2012

The efficient, high‐yield approaches to two novel regioisomeric salicyl aldehyde analogs, 4‐formyl‐13‐(2‐hydroxyphenyl)‐[2.2]paracyclophane and 4‐formyl‐12‐(2‐hydroxyphenyl)‐[2.2]paracyclophane (iso‐FHPhPC and pseudo‐FHPhPC, respectively), constructed on the basis of an aryl[2.2]paracyclophane backbone are described. The key stage of the backbone formation is the Suzuki cross‐coupling of paracyclophanyl halides with arylboronic acids. Efficient procedures for the resolution of the racemic hydroxy aldehydes into enantiomers via Schiff bases with enantiomers of α‐phenylethyl amine were elaborated, and the absolute configurations of enantiomers were established on the basis of X‐ray analysis of diastereomeric imines. Starting from these chiral hydroxy aldehydes the first representatives of bi‐, tri‐, and tetradentate phenoxy‐imine ligands belonging to an aryl[2.2]paracyclophane family were obtained. The induction power of the ligands was tested in the Et2Zn asymmetric addition to aldehydes.
Improving fMRI activation detection sensitivity using intervoxel coherence mapping
Authors: Wang Ze , Li Zhengjun , Pluta John , Detre John A.
Published: February 2012

Spatiotemporal data coherence widely exists in fMRI data and can be potentially used to increase brain activation detection. To assess this possibility, a two‐stage fMRI data analysis method was presented in this work. Standard voxelwise general linear model (GLM) was used to first exclude voxels with low correlation to the functional design, and an intervoxel coherence map (ICM) was then calculated voxel by voxel to locate brain regions, which were most consistently activated during the functional experiment. Population inference about the detected effects was provided through random effect analysis or permutation testing. Evaluations using synthetic data and scene‐encoding memory task fMRI data both showed enhanced activation detection performance for the proposed method when compared with standard GLM. © 2012 Wiley Periodicals, Inc. Int J Imaging Syst Technol, 22, 33–36, 2012
Improving the accuracy of cross‐relaxation imaging
Authors: Stikov Nikola
Published: February 2012

Cross‐relaxation imaging (CRI) provides biomarkers sensitive to the macromolecular content of tissue. Although the CRI parameters are sufficiently precise to exhibit significant correlations with macromolecular content in tissue, their accuracy is hindered by the CRI modeling and measurement variability. In this article, several sources of CRI variability are examined, such as T1 mapping bias, magnetization transfer signal drift, and inaccuracies due to tissue modeling. Simple corrections schemes are proposed to account for these effects and to improve the CRI accuracy. © 2012 Wiley Periodicals, Inc. Int J Imaging Syst Technol, 22, 67–72, 2012
Cytotoxicity of dioscin in human gastric carcinoma cells through death receptor and mitochondrial pathways
Authors: Hu Mingming , Xu Lina , Yin Lianhong , Qi Yan , Li Hua , Xu Youwei , Han Xu , Peng Jinyong , Wan Xianyao
Published: February 2012

In the present study, the antiproliferative effect of dioscin on human gastric carcinoma SGC‐7901 cells was confirmed by 3‐(4, 5‐dimethylthiahiazo‐zyl)‐2, 5‐dip‐henytetrazolium bromide and flow cytometry assays. Through acridine orange–ethidium bromide double fluorescent staining, apoptotic morphology of the cells was observed. Radioimmunoassays showed that the tumor necrosis factor (TNF)‐α concentration in cells treated with dioscin significantly increased compared with untreated cells. Several proteins and mRNA related to the mitochondrial and death receptor pathways were investigated. We found that the expression of Bid, bcl‐2 and bcl‐xl was markedly downregulated, and the expression of Bak and Bax was upregulated. In addition, cytochrome c was released from the mitochondria into the cytosol, which indicates activation of the mitrochondrial pathway by dioscin. Furthermore, upregulation of Fas, FasL (Fas ligand), TNF‐α, TNF receptor‐1, TNF receptor‐associated factor 1 and Fas‐associated protein with death domain demonstrated involvement of the death receptor pathway. Increased mRNA expression of p53 was also found in dioscin‐treated SGC‐7901 cells, and the activation of caspase‐3 and −8 was also observed. Consequently, this study clarifies the mechanism underlying the anticancer effect of dioscin, and also indicates that dioscin may be a potential drug treatment for human gastric cancer. Copyright © 2012 John Wiley & Sons, Ltd.
Stress shielding and fatigue limits of poly‐ether‐ether‐ketone dental implants
Authors: Lee Woo‐Taek , Koak Jai‐Young , Lim Young‐Jun , Kim Seong‐Kyun , Kwon Ho‐Beom , Kim Myung‐Joo
Published: February 2012

The poly‐ether‐ether‐ketone (PEEK) polymer is of great interest as an alternative to titanium in orthopedics because of its biocompatibility and low elastic modulus. This study evaluated the fatigue limits of PEEK and the effects of the low elastic modulus PEEK in relation to existing dental implants. Compressive loading tests were performed with glass fiber‐reinforced PEEK (GFR‐PEEK), carbon fiber‐reinforced PEEK (CFR‐PEEK), and titanium rods. Among these tests, GFR‐PEEK fatigue tests were performed according to ISO 14801. For the finite element analysis, three‐dimensional models of dental implants and bone were constructed. The implants in the test groups were coated with a 0.5‐mm thick and 5‐mm long PEEK layer on the upper intrabony area. The strain energy densities (SED) were calculated, and the bone resorption was predicted. The fatigue limits of GFR‐PEEK were 310 N and were higher than the static compressive strength of GFR‐PEEK. The bone around PEEK‐coated implants showed higher levels of SED than the bone in direct contact with the implants, and the wider diameter and stiffer implants showed lower levels of SED. The compressive strength of the GFR‐PEEK and CFR‐PEEK implants ranged within the bite force of the anterior and posterior dentitions, respectively, and the PEEK implants showed adequate fatigue limits for replacing the anterior teeth. Dental implants with PEEK coatings and PEEK implants may reduce stress shielding effects. Dental implant application of PEEK polymer—fatigue limit and stress shielding. © 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2012
Development of a probucol‐releasing antithrombogenic drug eluting stent
Authors: Vedantham Kumar , Chaterji Somali , Kim Sung Won , Park Kinam
Published: February 2012

The success of drug eluting stents (DESs) has been challenged by the manifestation of late stent thrombosis after DES implantation. The incomplete regeneration of the endothelial layer poststenting triggers adverse signaling processes precipitating in thrombosis. Various approaches have been attempted to prevent thrombosis, including the delivery of biological agents, such as estradiol, that promote endothelialization, and the use of natural polymers as coating materials. The underlying challenge has been the inability to release the biological agent in synchronization with the temporal sequence of vascular wound healing in vivo. The natural healing process of the endothelium after an injury starts after a week and may take up to a month in humans. This article presents a novel DES formulation using a hemocompatible polyurethane (PU) matrix to sustain the release of probucol (PB), an endothelial agonist, by exploiting the greater difference in the solubility parameters of PB and PU. This results in the formation of crystalline PB aggregates retarding drug release from PU. The physicochemical properties of PB in PU were confirmed using differential scanning calorimetry and X‐ray diffraction. Drug‐polymer compatibility was examined using infrared spectral analysis. Also, in vitro studies using primary human aortic endothelial cells resulted in the selection of 5% w/w PB as the optimal dose, to be further tested in vitro and in vivo. This work develops and tests a promising new DES formulation to enable faster endothelial cell proliferation poststenting, potentially minimizing the incidence and severity of thrombotic events after DES implantation. © 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2012.