bluuebunny/crossref_metadata_2025 huggingface dataset:
Optimal pollution tax under imperfect competition and international trade: the small country case
Authors: SAMPAOLESI ALEJANDRO
Published: August 2010

This work depicts the possibility of setting up an optimal pollution tax under non-competitive markets and international trade in a small country. The model employed describes a situation of partial equilibrium characterized by imperfect competition among domestic producers, where the domestic good is a substitute for an imported polluting commodity. In this framework, we also bring in the possibility that the domestic firms can introduce innovation offsets via their investment in R&D. From the results, the optimal pollution tax under domestic distortions can be expressed as a function of a ‘domestic production effect’ and a ‘pollution effect’. Furthermore, when the firms execute R&D expenditures, the optimal policy adds an ‘innovation effect’, which captures the change in welfare coming from a decrease in total costs and can lead our results to a win–win situation.
Homesickness for a foreign country: nostalgia and colonisation
Authors: McQueen Rob
Published: August 2010

‘[T]he other is the phantasm of historiography, the object that it seeks, honors and buries. A labor of separation concerning this uncanny and fascinating proximity is effected…Alphonse Dupront has said, “The sole historical quest for ‘meaning’ remains indeed a quest for the Other, but however contradictory it may be, this project aims at ‘understanding’ and, through ‘meaning’ at hiding the alterity of this foreigner; or, in what amounts to the same thing, it aims at calming the dead who still haunt the present, and at offering them scriptural tombs”.’ (De Certeau, 1998, p. 2)
L'enclavement huméroradial
Authors: Van Linthoudt
Published: August 2010

Schmerzen lateral am Ellbogen sind häufig. Eine selten erwähnte und häufig verkannte Ursache ist das Impingement der humeroradialen Plika oder von hypertrophen Synovialzotten. Bei Sportlern bzw. gewissen Berufsgruppen sollte an diese Ätiologie gedacht werden. Der Schmerz kann akut auftreten mit lokalen Entzündungszeichen. Manchmal besteht eine explizite Druckdolenz über dem lateralen Gelenkspalt unterhalb des lateralen Epikondylus. Die Patienten beschreiben ein Schnappen, Blockieren und/oder Bewegungseinschränkungen. Die MRT-Arthrographie ist die bildgebende Methode der Wahl. Der Behandlungsansatz ist primär konservativ, gelegentlich bedarf es einer arthroskopischen Intervention.
Psychological Assessment of Two Adolescents with Cystic Fibrosis Awaiting Lung Transplants
Authors: Flahault Cécile
Published: August 2010

This paper is based on two clinical cases of adolescents suffering from cystic fibrosis who were evaluated before lung transplant by the Rorschach Comprehensive System and an interview. Clinical practice calling for the assessment with the Rorschach shows how this procedure may provide useful information for case conceptualization in a medical setting. Two clinical cases are provided and interpreted. Data show that the Rorschach allows us to explore the patients’ psychological issues as well as their defensive organizations. It provides a useful complement to the interview, especially access to depressive feelings hidden by defensive functioning. Articulation with treatment planning issues and follow-up data are also provided on the two cases.
The Rorschach in Planning Treatment of Alcohol Addiction Patients
Authors: Kostogianni Nikoleta
Published: August 2010

The present study demonstrates the utility of information derived from the Rorschach Comprehensive System (CS) in treatment planning for alcohol-dependent patients through two clinical cases. These case studies were selected because they clearly demonstrate the complex relationship between alcohol addiction, clinical syndromes, and personality. Both patients were women. The assessment took place on the third week of an inpatient alcohol rehabilitation program. The referral questions included (1) the magnitude of the emotional distress, (2) the motivation to change, and (3) the adequacy of their interpersonal style with our outpatient group treatment lasting 12 weeks. Each patient was assessed on the MINI, the SCID-II, the MMPI-2, and the Rorschach CS. Rorschach findings completed the information obtained by the clinical interview, the structured interviews, and the self-report inventory by generating hypotheses about clinical diagnoses, the role of alcohol, motivation for change, treatment targets, patients’ strengths and interpersonal style, as well as the potential obstacles for treatment and therapeutic relationship. Specific treatment plans and pertinent techniques for therapy were ascertained for each patient.
Seasonally resolved growth of freshwater bivalves determined by oxygen and carbon isotope shell chemistry
Authors: Versteegh Emma A. A. , Vonhof Hubert B. , Troelstra Simon R. , Kaandorp Ron J. G. , Kroon Dick
Published: August 2010

By means of a monitoring experiment in two rivers in the Netherlands, we establish a relationship between seasonally resolved growth rates in unionid freshwater bivalves and their environment. We reconstructed these seasonally resolved growth rates by using relationships of stable isotopes in the shells and their ambient river water. The reconstructed growth rates reveal that shells grow fastest in spring‐early summer, when highest food availability occurs in the rivers. In addition, the reconstructed growth rates show that onset and cessation of growth are mainly influenced by water temperature.
Global analysis of cloud phase and ice crystal orientation from Cloud‐Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) data using attenuated backscattering and depolarization ratio
Authors: Yoshida R. , Okamoto H. , Hagihara Y. , Ishimoto H.
Published: August 2010

A method for discriminating cloud particle types was developed using lidar backscattering copolarization and cross‐polarization channel measurements from Cloud‐Aerosol Lidar With Orthogonal Polarization (CALIOP) on board Cloud‐Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO). In spaceborne lidar measurements, significant multiple scattering effects discriminate between cloud water and ice difficult using the depolarization ratio (δ). We theoretically estimated the relationship between δ and cloud extinction on the basis of the backward Monte Carlo method. Cloud particle type was determined by the combined use of δ and the ratio of attenuated backscattering coefficients for two vertically consecutive layers. Ice particles were further classified into two categories: randomly oriented ice crystals (3‐D ice) and horizontally oriented plates (2‐D plate). The method was applied to CALIOP data for September–November 2006. We found that 3‐D ice generally occurred colder than −20°C, whereas 2‐D plate occurred between −10°C and −20°C, with high‐occurrence frequency in high‐latitude regions. We compared the results to those obtained using the vertical feature mask (VFM). The VFM tended to show a homogeneous cloud type through the entire cloud layer in vertical directions and misclassified 2‐D plate as water. The ratio of water particles relative to ice particles decreased with decreasing temperature. By the proposed method, water cloud occurrence in subtropical and high‐latitude regions was greater (up to 20%) than in the other regions below −10°C; however, the VFM results did not show such dependence on latitude. Comparison of ice and water cloud between our results and Moderate Resolution Imaging Spectroradiometer (MODIS) products showed better agreement for water cloud than for ice cloud.
Nitrogen isotope record of a perturbed paleoecosystem in the aftermath of the end‐Triassic crisis, Doniford section, SW England
Authors: Paris Guillaume , Beaumont Valérie , Bartolini Annachiara , Clémence Marie‐Emilie , Gardin Silvia , Page Kevin
Published: August 2010

The Triassic‐Jurassic transition (TJ) is characterized by successive perturbations of the carbon cycle during a time of biotic disruption as recorded by the carbon isotopic composition of organic matter (δ13Corg). The nitrogen isotopic composition of sedimentary organic matter (δ15Norg) constitutes a key parameter to explore the functioning of the ecosystem during carbon cycle perturbations and biological crises, because it provide information on seawater redox conditions and/or nutrient cycling. Here we report the first continuous δ15Norg record across the TJ transition at the Doniford Bay section (Bristol Channel Basin, UK), combined with δ13Corg, kerogen typology and carbon (δ13Cmin) and oxygen (δ18Omin) isotopic composition of bulk carbonates. The end Triassic is characterized by a major negative excursion both in δ13Corg and δ13Cmin, very low TOC (Total Organic Carbon, wt%) and high δ15Norg values, associated with a sea level lowstand. A second δ13Corg negative excursion occurs during the lower Hettangian. This interval is characterized by phases of carbonate production increase alternated with phases of exceptional accumulations of type I organic matter (up to 12%) associated with lower δ15Norg and δ13Corg. This alternation likely reflects a succession of nutrient input increase to the basin leading to enhanced productivity and eutrophication, which promoted a primary production driven by organic‐walled prokaryotic organisms. The following OM export increase generates anaerobic conditions within the basin. These events occur between periods of relatively good seawater column ventilation and nutrient recycling boosting the carbonate producer recovery. Ecosystems remain perturbed in the Bristol Channel Basin during the aftermath of the end‐Triassic crisis.
Mineral magnetic properties of surface soils and sands across four North African transects and links to climatic gradients
Authors: Lyons Richard , Oldfield Frank , Williams Earle
Published: August 2010

In light of their earlier success in characterizing and differentiating soils, sediments and atmospheric particulates, magnetic measurements were carried out on samples of North African surface soils and sands. The main aims were to document spatial variations in magnetic properties, explore their possible links to climatic gradients and their likely basis, and thereby help to differentiate potential sources for Sahara/Sahel‐derived dusts. Samples were collected along four broadly north‐to‐south orientated transects located in Egypt, Niger, Mali, and Benin and southern Togo. These transects cover major climatic gradients ranging from hyper‐arid to tropical. Across the rainfall range spanned by the Niger and Mali Transects (<100 to >800 mm/yr) there are significant north‐to‐south gradients in magnetic mineral concentrations. This is seen most clearly in the concentrations of the finest ferrimagnetic minerals (magnetite/maghemite), which are strongly represented in the clay fraction. Concentrations of the imperfect antiferromagnetic minerals (predominantly haematite) also increase with increasing rainfall. By analogy with studies spanning a similar rainfall gradient in areas of more uniform lithology, we suggest that the most likely cause for these trends is increased chemical weathering linked to the progressively wetter climate across the Sahara/Sahel transition. Within the set of samples from Egypt (rainfall >100 to <5 mm/yr), there is a marked gradient in the coercivity of remanence in the antiferromagnetic minerals present, with coercivity increasing southwards, paralleling the trend toward increasing aridity. Given the strong spatial discrimination demonstrated, especially in the Niger and Mali transects, these potentially climate‐linked gradients hold out the promise of discriminating between dust source regions.
Very near‐bottom tidal straining in a sea strait
Authors: van Haren Hans
Published: August 2010

Large vertical temperature differences up to 3°C m−1 are observed very near (<0.5 m from) the 2‐m sand‐waves bottom in a 20–25 m deep sea strait dominated by tidal flows >1 m s−1. The upper sensor at 0.42 m above the bottom (mab) follows typical temperature variations higher up in the water column, being −90° out‐of‐phase with the main along‐channel current. In contrast, the lower sensor at 0.08 mab is approximately +30–50° more in‐phase with the free‐stream current. The data confirm the mechanism of “tidal straining”, but much closer to the bottom than previously observed and in a 3‐D version with cross‐flow influences. In this mechanism, turbulent shear flow and horizontal density gradients create stable stratification during ebb and unstable conditions during flood. Here, stratification provides a slippery boundary flow‐condition and periodic support of short‐scale internal waves with periods down to 50 s.
Ascl1 Lineage Cells Contribute to Ischemia-Induced Neurogenesis and Oligodendrogenesis
Authors: Zhang Rui Lan , Chopp Michael , Roberts Cindi , Jia Longfei , Wei Min , Lu Mei , Wang Xinli , Pourabdollah Siamak , Zhang Zheng Gang
Published: August 2010

Neural and oligodendrocyte progenitor cells in the adult brain express Ascl1 (also known as Mash1), a basic helix-loop-helix transcription factor. We examined the progeny and fate of this progenitor population in adult male Ascl1-CreER™R26R-stop-yellow fluorescent protein mice subjected to right middle cerebral occlusion over 60 days after stroke using inducible Cre recombination to label Ascl1-expressing cells at poststroke days 2 to 6 in vivo. Seven days after stroke, a substantial increase in Ascl1 lineage cells was detected in the ipsilateral subventricular zone (SVZ), striatum, and corpus callosum. These cells exhibited proliferating progenitor cell phenotypes (Sox2+, BrdU+, and Ki67+). Although Ascl1 lineage cells in the ipsilateral SVZ gradually decreased during 14 to 60 days after stroke, Ascl1 lineage cells in the ischemic striatum revealed a remarkable increase during this period. Thirty and sixty days after stroke, Ascl1 lineage cells in the ischemic striatum gave rise to GABAergic neurons and mature oligodendrocytes. In contrast, none of the Ascl1 lineage cells in the contralateral striatum exhibited neuronal and oligodendrocyte phenotypes. Moreover, Ascl1 lineage cells in the corpus callosum were only fated to become mature oligodendrocytes. Our data suggest that Ascl1 lineage cells contribute to stroke-induced neurogenesis and oligodendrogenesis in the adult ischemic brain.
Iron and Early Brain Injury after Subarachnoid Hemorrhage
Authors: Loftspring Matthew C
Published: August 2010

Aneurysmal subarachnoid hemorrhage (SAH) affects approximately 27,000 Americans per year. Although delayed cerebral vasospasm is of high clinical significance, mortality within the first 2 days may approach 30%. In this issue of the Journal of Cerebral Blood Flow and Metabolism, Lee et al have studied the role of iron in early brain injury after experimental SAH. They found that iron chelation with deferoxamine reduced mortality and oxidative DNA damage, and lessened the induction of iron-handling proteins. Taken together, these results highlight the deleterious potential of blood breakdown products and provide an insight into future intervention.
Parametric Mapping of [18F]Fluoromisonidazole Positron Emission Tomography using Basis Functions
Authors: Hong Young T , Beech John S , Smith Rob , Baron Jean-Claude , Fryer Tim D
Published: August 2010

In this study, we show a basis function method (BAFPIC) for voxelwise calculation of kinetic parameters ( K1, k2, k3, Ki) and blood volume using an irreversible two-tissue compartment model. BAFPIC was applied to rat ischaemic stroke micro-positron emission tomography data acquired with the hypoxia tracer [18F]fluoromisonidazole because irreversible two-tissue compartmental modelling provided good fits to data from both hypoxic and normoxic tissues. Simulated data show that BAFPIC produces kinetic parameters with significantly lower variability and bias than nonlinear least squares (NLLS) modelling in hypoxic tissue. The advantage of BAFPIC over NLLS is less pronounced in normoxic tissue. Ki determined from BAFPIC has lower variability than that from the Patlak–Gjedde graphical analysis (PGA) by up to 40% and lower bias, except for normoxic tissue at mid-high noise levels. Consistent with the simulation results, BAFPIC parametric maps of real data suffer less noise-induced variability than do NLLS and PGA. Delineation of hypoxia on BAFPIC k3 maps is aided by low variability in normoxic tissue, which matches that in Ki maps. BAFPIC produces Ki values that correlate well with those from PGA ( r2 = 0.93 to 0.97; slope 0.99 to 1.05, absolute intercept < 0.00002 mL/g per min). BAFPIC is a computationally efficient method of determining parametric maps with low bias and variance.
Brain Glutamine Synthesis Requires Neuronal-Born Aspartate as Amino Donor for Glial Glutamate Formation
Authors: Pardo Beatriz , Rodrigues Tiago B , Contreras Laura , Garzón Miguel , Llorente-Folch Irene , Kobayashi Keiko , Saheki Takeyori , Cerdan Sebastian , Satrústegui Jorgina
Published: August 2010

The glutamate–glutamine cycle faces a drain of glutamate by oxidation, which is balanced by the anaplerotic synthesis of glutamate and glutamine in astrocytes. De novo synthesis of glutamate by astrocytes requires an amino group whose origin is unknown. The deficiency in Aralar/ AGC1, the main mitochondrial carrier for aspartate–glutamate expressed in brain, results in a drastic fall in brain glutamine production but a modest decrease in brain glutamate levels, which is not due to decreases in neuronal or synaptosomal glutamate content. In vivo13C nuclear magnetic resonance labeling with 13C2acetate or (1-13C) glucose showed that the drop in brain glutamine is due to a failure in glial glutamate synthesis. Aralar deficiency induces a decrease in aspartate content, an increase in lactate production, and lactate-to-pyruvate ratio in cultured neurons but not in cultured astrocytes, indicating that Aralar is only functional in neurons. We find that aspartate, but not other amino acids, increases glutamate synthesis in both control and aralar-deficient astrocytes, mainly by serving as amino donor. These findings suggest the existence of a neuron-to-astrocyte aspartate transcellular pathway required for astrocyte glutamate synthesis and subsequent glutamine formation. This pathway may provide a mechanism to transfer neuronal-born redox equivalents to mitochondria in astrocytes.
Brain Blood Flow in Andean and Himalayan High-Altitude Populations: Evidence of Different Traits for the Same Environmental Constraint
Authors: Jansen Gerard FA , Basnyat Buddha
Published: August 2010

Humans have populated the Tibetan plateau much longer than the Andean Altiplano. It is thought that the difference in length of occupation of these altitudes has led to different responses to the stress of hypoxia. As such, Andean populations have higher hematocrit levels than Himalayans. In contrast, Himalayans have increased circulation to certain organ systems to meet tissue oxygen demand. In this study, we hypothesize that cerebral blood flow ( CBF) is higher in Himalayans than in Andeans. Using a MEDLINE and EMBASE search, we included 10 studies that investigated CBF in Andeans and Himalayans between 3,658 and 4,330 m altitude. The CBF values were corrected for differences in hematocrit and arterial oxygen saturation. The data of these studies show a mean hematocrit of 50% in Himalayans and 54.1% in Andeans. Arterial oxygen saturation was 86.9% in Andeans and 88.4% in Himalayans. The CBF in Himalayans was slightly elevated compared with sea-level subjects, and was 24% higher compared with Andeans. After correction for hematorit and arterial oxygen saturation, CBF was ~20% higher in Himalayans compared with Andeans. Altered brain metabolism in Andeans, and/or increased nitric oxide availability in Himalayans may have a role to explain this difference in brain blood flow.
Structured digital tables on the Semantic Web: toward a structured digital literature
Authors: Cheung Kei‐Hoi , Samwald Matthias , Auerbach Raymond K , Gerstein Mark B
Published: August 2010

In parallel to the growth in bioscience databases, biomedical publications have increased exponentially in the past decade. However, the extraction of high‐quality information from the corpus of scientific literature has been hampered by the lack of machine‐interpretable content, despite text‐mining advances. To address this, we propose creating a structured digital table as part of an overall effort in developing machine‐readable, structured digital literature. In particular, we envision transforming publication tables into standardized triples using Semantic Web approaches. We identify three canonical types of tables (conveying information about properties, networks, and concept hierarchies) and show how more complex tables can be built from these basic types. We envision that authors would create tables initially using the structured triples for canonical types and then have them visually rendered for publication, and we present examples for converting representative tables into triples. Finally, we discuss how ‘stub’ versions of structured digital tables could be a useful bridge for connecting together the literature with databases, allowing the former to more precisely document the later.
A model of yeast cell‐cycle regulation based on multisite phosphorylation
Authors: Barik Debashis , Baumann William T , Paul Mark R , Novak Bela , Tyson John J
Published: August 2010

In order for the cell's genome to be passed intact from one generation to the next, the events of the cell cycle (DNA replication, mitosis, cell division) must be executed in the correct order, despite the considerable molecular noise inherent in any protein‐based regulatory system residing in the small confines of a eukaryotic cell. To assess the effects of molecular fluctuations on cell‐cycle progression in budding yeast cells, we have constructed a new model of the regulation of Cln‐ and Clb‐dependent kinases, based on multisite phosphorylation of their target proteins and on positive and negative feedback loops involving the kinases themselves. To account for the significant role of noise in the transcription and translation steps of gene expression, the model includes mRNAs as well as proteins. The model equations are simulated deterministically and stochastically to reveal the bistable switching behavior on which proper cell‐cycle progression depends and to show that this behavior is robust to the level of molecular noise expected in yeast‐sized cells (∼50 fL volume). The model gives a quantitatively accurate account of the variability observed in the G1‐S transition in budding yeast, which is governed by an underlying sizer+timer control system.
Modeling genome‐wide replication kinetics reveals a mechanism for regulation of replication timing
Authors: Yang Scott Cheng‐Hsin , Rhind Nicholas , Bechhoefer John
Published: August 2010

Microarrays are powerful tools to probe genome‐wide replication kinetics. The rich data sets that result contain more information than has been extracted by current methods of analysis. In this paper, we present an analytical model that incorporates probabilistic initiation of origins and passive replication. Using the model, we performed least‐squares fits to a set of recently published time course microarray data on Saccharomyces cerevisiae. We extracted the distribution of firing times for each origin and found that the later an origin fires on average, the greater the variation in firing times. To explain this trend, we propose a model where earlier‐firing origins have more initiator complexes loaded and a more accessible chromatin environment. The model demonstrates how initiation can be stochastic and yet occur at defined times during S phase, without an explicit timing program. Furthermore, we hypothesize that the initiators in this model correspond to loaded minichromosome maintenance complexes. This model is the first to suggest a detailed, testable, biochemically plausible mechanism for the regulation of replication timing in eukaryotes.
Golgi apparatus fragmentation as a mechanism responsible for uniform delivery of uroplakins to the apical plasma membrane of uroepithelial cells
Authors: Kreft Mateja Erdani , Di Giandomenico Daniele , Beznoussenko Galina V. , Resnik Nataša , Mironov Alexander A. , Jezernik Kristijan
Published: August 2010

Background information. The GA (Golgi apparatus) has an essential role in membrane trafficking, determining the assembly and delivery of UPs (uroplakins) to the APM (apical plasma membrane) of superficial UCs (uroepithelial cells) of urinary bladder. UPs are synchronously and uniformly delivered from the GA to the APM by DFVs (discoidal‐ or fusiform‐shaped vesicles); however, the mechanism of UP delivery is not known. We have used the culture model of UCs with the capacity to undergo terminal differentiation to study the process of uniform delivery of DFVs to the APM and to elucidate the mechanisms involved.

Results. By three‐dimensional localization using confocal microscopy of immunofluorescence‐labelled GA‐related markers [GM130 (cis‐Golgi matrix protein of 130 kDa), GS15 (Golgi Snare 15 kDa), GS28 and giantin], uroepithelial differentiation‐related markers (UPs), MTs (microtubules; α‐tubulin) and intermediate filaments [CK7 (cytokeratin 7) and CK20], we found that in non‐differentiated, UP‐negative UCs the GA is mostly organized as a single ribbon‐like structure close to the nucleus, whereas in differentiated, UP‐positive UCs the GA is fragmented and spread almost through the entire cell. The FRAP (fluorescence recovery after photobleaching) experiments on the UCs transfected with GalT (trans‐Golgi/TGN enzyme β1,4‐galactosyltransferase) fused to fluorescent protein showed that Golgi‐resident enzyme cycles freely within ribbon‐like GA but not within fragmented GA. By CLEM (correlative light—electron microscopy), we examined the GA fragments in cells expressing UPs. We found that GA fragments are fully functional and similar to the GA fragments that are formed after nocodazole treatment. Furthermore, we demonstrated that the reorganization of GA into a fragmented form is associated with the impairment of the MT organization in the basal, central and subapical cytoplasm and the accumulation of intermediate filaments in the apical cytoplasm that could affect the kinetics of MT star leading to the peripheral fragmentation of the GA in the differentiated UCs.

Conclusions. The fragmentation of the GA and the subsequent spreading of GA to the cell periphery represent one of the key events that promote the uniform delivery of UPs over the entire APM of differentiating UCs and thus are of major importance in the final proper formation and maintenance of the blood—urine barrier.
The chaperone proteins HSP70, HSP40/DnaJ and GRP78/BiP suppress misfolding and formation of β-sheet-containing aggregates by human amylin: a potential role for defective chaperone biology in Type 2 diabetes
Authors: Chien Vita , Aitken Jacqueline F. , Zhang Shaoping , Buchanan Christina M. , Hickey Anthony , Brittain Thomas , Cooper Garth J. S. , Loomes Kerry M.
Published: August 2010

Misfolding of the islet β-cell peptide hA (human amylin) into β-sheet-containing oligomers is linked to β-cell apoptosis and the pathogenesis of T2DM (Type 2 diabetes mellitus). In the present study, we have investigated the possible effects on hA misfolding of the chaperones HSP (heat-shock protein) 70, GRP78/BiP (glucose-regulated protein of 78 kDa/immunoglobulin heavy-chain-binding protein) and HSP40/DnaJ. We demonstrate that hA underwent spontaneous time-dependent β-sheet formation and aggregation by thioflavin-T fluorescence in solution, whereas rA (rat amylin) did not. HSP70, GRP78/BiP and HSP40/DnaJ each independently suppressed hA misfolding. Maximal molar protein/hA ratios at which chaperone activity was detected were 1:200 (HSP70, HSP40/DnaJ and GRP78/BiP). By contrast, none of the chaperones modified the secondary structure of rA. hA, but not rA, was co-precipitated independently with HSP70 and GRP78/BiP by anti-amylin antibodies. As these effects occur at molar ratios consistent with chaperone binding to relatively rare misfolded hA species, we conclude that HSP70 and GRP78/BiP can detect and bind misfolded hA oligomers, thereby effectively protecting hA against bulk misfolding and irreversible aggregation. Defective β-cell chaperone biology could contribute to hA misfolding and initiation of apoptosis in T2DM.
Photophysics of fluorinated benzene. I. Quantum chemistry
Authors: Mondal T. , Mahapatra S.
Published: August 2010

The electronic structure of energetically low-lying excited singlet states of fluorobenzene molecules is investigated here. Increasing fluorine substitution alters the nature of the excited electronic states and the so-called perfluoro effect is observed for penta- and hexafluorobenzene. Detailed quantum chemistry calculations are carried out at the equation-of-motion coupled-cluster singles and doubles level of theory to establish the potential energy surfaces of the low-lying electronic states of mono-, di- (ortho- and meta-), and pentafluorobenzene molecules. A sequence of low-energy conical intersections among the electronic potential energy surfaces is established. It is found that increasing fluorine substitution lowers the energy of the πσ∗ electronic state and leads to conical intersections between the S1 and S2 electronic states of pentafluorobenzene. Existence of numerous conical intersections among the excited electronic states of these molecules forms the mechanistic details underlying their nonradiative internal conversion. In particular, the slow and biexponential fluorescence emission in pentafluorobenzene is attributed to the existence of low-lying S1-S2 conical intersections. The electronic structure data are analyzed in detail and the coupling mechanism among various electronic excited states of mono-, di-, and pentafluorobenzene molecules is established.
Photophysics of fluorinated benzene. II. Quantum dynamics
Authors: Mondal T. , Mahapatra S.
Published: August 2010

Nuclear dynamics in the coupled electronic states of mono-, di-(ortho and meta), and pentafluorobenzene molecules is investigated here. Attempts are specifically made to understand the complexity and broadening of the recorded gas phase electronic absorption spectra of these molecules. Justification is also provided for the low quantum yield of fluorescence emission with increasing number of fluorine substitutions. The nuclear dynamics is simulated from first principles both by time-independent and time-dependent quantum mechanical methods. Potential energy surfaces of the low-lying excited electronic states of these molecules constructed in Paper I [Mondal and Mahapatra, J. Chem. Phys. 133, 084304 (2010)] are employed for the purpose. Theoretical results presented in this paper are compared with the available experimental data and the agreement between the two is found to be excellent. While structured electronic absorption bands are observed for the S1 state of mono- and difluorobenzene molecules, the same for the pentafluorobenzene is broad and structureless. Occurrence of S1-S2 conical intersections in pentafluorobenzene leads to a nonradiative internal conversion of the S1 state in ∼165 fs and contributes to the broadening of the S1←S0 absorption band and a biexponential decay of its fluorescence emission.
Multiphoton-absorption induced ultraviolet luminescence of ZnO nanorods using low-energy femtosecond pulses
Authors: Das Susanta Kumar , Biswas Mahua , Byrne Daragh , Bock Martin , McGlynn Enda , Breusing Markus , Grunwald Ruediger
Published: August 2010

Multiphoton-absorption (MPA) induced ultraviolet (UV) luminescence of ZnO nanorods grown by vapor phase transport was demonstrated using ultrafast excitation at pulse energies in the few nanojoules range, directly generated by a Ti:sapphire laser oscillator at wavelengths around 800 nm. The dependence of the UV luminescence on the excitation density reveals a two-photon absorption process as the responsible excitation mechanism. The broad spectral bandwidth of the excitation pulses obviously promotes the feasibility of the observed two-photon channel. Theoretical estimates concerning the contribution of nonlinear absorbance strongly support the experimental findings. The essential conditions for proper utilization of this process are discussed.
2.0

μ
m
emission properties and energy transfer processes of Yb3+/Ho3+ codoped germanate glass
Authors: Xu Rongrong , Pan Jiajia , Hu Lili , Zhang Junjie
Published: August 2010

Ho 3 + doped germanate glass sensitized by Yb3+ has been investigated for potential application as a near-infrared laser material. The characteristic temperatures are determined by differential scanning calorimeter, and the absorption and emission spectra are measured. According to absorption spectra, Judd–Ofelt parameters and radiative transition probabilities are calculated and analyzed by Judd–Ofelt theory. The intensity of emission spectra shows a strong dependence upon the Yb3+ concentration. The result also indicates that Yb3+ plays an important role in the emission of 2.0 μm by transferring the 980 nm excitation energy to Ho3+. The energy transfer process from Yb3+ to Ho3+ is analyzed and the result shows that coefficient of the forward energy transfer Yb3+→Ho3+ is 19 times of magnitude larger than that of the backward energy transfer Yb3+←Ho3+. It is found that the highest gain in 2.0 μm region could be achieved from the germanate glass with 5.0 mol % Yb2O3 and 1.0 mol % Ho2O3. The present Yb3+/Ho3+ codoped germanate glass with high emission cross section of Ho3+:I57→I58 at 2.0 μm and efficient energy transfer from Yb3+ to Ho3+ will be a suitable material for developing solid state lasers around 2.0 μm.
Molecular dynamics simulation with weak coupling to heat and material baths
Authors: Eslami Hossein , Mojahedi Fatemeh , Moghadasi Jalil
Published: August 2010

A method for performing molecular dynamics simulation in the grand canonical ensemble is developed. The molecular dynamics, with coupling to an external bath, simulation method of [Berendsen et al., J. Chem. Phys. 81, 3684 (1984)] is extended for this purpose. Here the physical system of interest consists of real indistinguishable particles plus one fractional particle, whose potential energy of interaction with the rest of particles is scaled by a coupling parameter, ranging dynamically between zero and one. This coupling changes the number of particles in the system gradually and dynamically, depending on the target values of the excess chemical potential, temperature, and volume. A nonlinear scaling scheme has been adopted to scale the potential energy of interaction of the fractional particle with the rest of the system. The method has been employed to predict the density of compressed Lennard-Jones fluid, compatible with the target values of temperature and the excess chemical potential, over a wide range of temperatures and densities. The method has further been applied to do molecular dynamics simulation in the grand canonical ensemble for water and to predict its vapor-liquid phase coexistence point. The results obtained using this method are in complete agreement with previously reported results in the literature.
Phase-shift effect in capacitively coupled plasmas with two radio frequency or very high frequency sources
Authors: Xu Xiang , Zhao Shu-Xia , Zhang Yu-Ru , Wang You-Nian
Published: August 2010

A two-dimensional fluid model was built to study the argon discharge in a capacitively coupled plasma reactor and the full set of Maxwell equations is included in the model to understand the electromagnetic effect in the capacitive discharge. Two electrical sources are applied to the top and bottom electrodes in our simulations and the phase-shift effect is focused on. We distinguish the difference of the phase-shift effect on the plasma uniformity in the traditional radio frequency discharge and in the very high frequency discharge where the standing wave effect dominates. It is found that in the discharges with frequency 13.56 MHz, the control of phase difference can less the influence of the electrostatic edge effect, and it gets the best radial uniformity of plasma density at the phase difference π. But in the very high frequency discharges, the standing wave effect plays an important role. The standing wave effect can be counteracted at the phase difference 0, and be enhanced at the phase difference π. The standing wave effect and the edge effect are balanced at some phase-shift value between 0 and π, which is determined by discharge parameters.
Spectroscopic and upconversion properties of erbium-doped potassium lithium tantalate niobate crystals under 800 nm femtosecond laser excitation
Authors: Li Lei , Zhou Zhongxiang , Tian Hao , Gong Dewei , Yang Zhenling , Yang Yanqiang
Published: August 2010

The single crystals of tungsten bronze-type potassium lithium tantalate niobate doped with three concentrations erbium with good quality are grown using top-seed solution growth method. The unpolarized ultraviolet-visible-near infrared optical absorption spectra of these single crystals are measured at room temperature. The green and red upconversion emission properties are analyzed with respect to steady-state spectra and decay behaviors under 800 nm femtosecond laser excitation. The spectroscopic properties of Er3+ ions are studied on the basis of the Judd–Ofelt theory. 12 Er3+ ions absorption bands are observed ranging from 350 to 1650 nm, the lower limit is also the ultraviolet absorption edge of these crystals. The fluorescence branching ratio and radiative lifetime are calculated to support the upconversion mechanism. The relationship of the Judd–Ofelt parameters Ω4<Ω6 of Er3+ in these crystals is different from the general trend Ω2>Ω4>Ω6. Experimental results indicate that upconversion emission is a two-photon process. It follows that the shortening of lifetime and the increasing of intensities of red emission are due to the increase in Er3+ ions cluster sites. Excited state absorption and energy transfer processes lead to the green emission while cross relaxation process produces the red emission.
Effects of release holes on microscale solid–solid phononic crystals
Authors: Soliman Y. M. , Su M. F. , Leseman Z. C. , Reinke C. M. , El-Kady I. , Olsson R. H.
Published: August 2010

Solid–solid phononic crystals exhibit wider band gaps than those observed with air–solid phononic crystals. For micromachined phononic crystal devices it is advantageous to release the phononic crystal to avoid propagation losses. In a solid–solid phononic crystal operating in the low megahertz range, due to the large lattice constant, it is necessary to place release holes in the center of the inclusions to release devices from the substrate while minimizing the effect the release hole has on the band gap. In this report, we investigate the effect of release holes on phononic band gaps and highlight the need for careful design. It was determined that release holes of radius rair holes/rinclusion=0.26 can reliably release a phononic crystal membrane composed of W inclusions in SiO2 without significantly compromising the phononic band gap.
Long-range spontaneous structural ordering in barium stannate thin films
Authors: Takahashi R. , Valset K. , Folven E. , Eberg E. , Grepstad J. K. , Tybell T.
Published: August 2010

We have studied spontaneous structural ordering in epitaxial barium stannate thin films, grown on SrTiO3(001) substrates by pulsed laser deposition. X-ray diffraction analysis revealed satellite reflections around the Bragg peaks, indicative of nanoscale periodic ordering in the out-of-plane direction. We find that mass transport strongly affects this spontaneous ordering, and that the thin film growth rate can be used to tune the periodicity of the superlattices, here between 4.3 and 57.7 nm.
High-gain complementary inverter with InGaZnO/pentacene hybrid ambipolar thin film transistors
Authors: Liu Po-Tsun , Chou Yi-Teh , Teng Li-Feng , Fuh Chur-Shyang
Published: August 2010

Ambipolar thin film transistors (TFTs) with InGaZnO/pentacene heterostructure channels are demonstrated for a high-voltage-gain complementary metal oxide semiconductor (CMOS) inverter. The ambipolar TFT exhibits a electron mobility of 23.8 cm2/V s and hole mobility of 0.15 cm2/V s for the InGaZnO and pentacene, respectively. The thermal annealing process was also studied to adjust electron concentration reducing operating voltage of the CMOS inverter. The voltage gain achieves as high as 60 obtained in the first and third quadrants of the voltage transfer characteristic. The high performance and simple manufacture of the heterostructure CMOS inverter show promise as critical components in various electrical applications.
Ultrathin silicon nitride microring resonator for biophotonic applications at 970 nm wavelength
Authors: Goykhman Ilya , Desiatov Boris , Levy Uriel
Published: August 2010

We experimentally demonstrate a high-Q ultrathin silicon nitride microring resonator operating at wavelength of 970 nm that is favorable for large variety of biophotonic applications. Implementation of thin device layer of 200 nm allows enhanced interaction between the optical mode and environment, while still maintaining high quality factor of resonator. In addition, we show the importance of spectral window around 970 nm to improve device sensing capability.
Electroluminescence from Er-doped Si-rich silicon nitride light emitting diodes
Authors: Yerci S. , Li R. , Dal Negro L.
Published: August 2010

Electrical devices based on Erbium (Er) doping of silicon nitride have been fabricated by reactive cosputtering and intense, room temperature Er electroluminescence was observed in the visible (527, 550, and 660 nm) and near-infrared (980 and 1535 nm) spectral ranges at low injection voltages (<5 V EL turn on). The electrical transport mechanism in these devices was investigated and the excitation cross section for the 1535 nm Er emission was measured under electrical pumping, resulting in a value (1.2×10−15 cm2) comparable to optical pumping. These results indicate that Er-doped silicon nitride has a large potential for the engineering of light sources compatible with Si technology.
Footprints Sticking out of the Sand. Part 1: Children's Perception of Naturalistic and Embossed Symbol Stimuli
Authors: Stone James V , Pascalis Olivier
Published: August 2010

The shading information in images that depict surfaces of three-dimensional objects cannot be perceived correctly unless the direction of the illuminating light source is known, and, in the absence of this knowledge, adults interpret such images by assuming that light comes from above. In order to investigate if children make use of a similar assumption, we analysed data from 171 children between the ages of 4.6 and 10.8 years using 10 images (shown upright and upside-down) that could be perceived as either convex or concave. Each of five images depicted a naturalistic picture (eg a footprint), each of the other five depicted an embossed symbol (eg a square). On each of 20 trials, a child was presented with either an upright or upside-down image, and indicated whether the depicted shape appeared convex or concave. Our main findings are that (i) naturalistic stimuli are significantly more likely to be perceived as if light comes from above than symbol stimuli, and (ii) children's propensity to interpret stimuli as if light comes from above increases significantly with age, and at a similar rate for naturalistic and symbol stimuli. These results suggest that, irrespective of any innate competence, children's ability to interpret shading information is gradually refined throughout childhood.
Empowerment and change management in Aboriginal organisations: a case study
Authors: McEwan Alexandra B. , Tsey Komla , McCalman Janya , Travers Helen J.
Published: August 2010

The social organisation of work, management styles and social relationships in the workplace all matter for health. It is now well recognised that people who have control over their work have better health and that stress in the workplace increases the level of disease. In the context of organisational change, the potential benefits of empowerment strategies are two-fold: a positive impact on the organisation’s effectiveness and enhancements in staff health, wellbeing and sense of control. This case study describes the University of Queensland Empowerment Research Program’s experience working with the Apunipima Cape York Health Council in a change management process. Participatory action research and empowerment strategies were utilised to facilitate shifts in work culture and group cohesion towards achieving Apunipima’s vision of being an effective lead agency for Indigenous health reform in Cape York. As part of the project, staff morale and confidence were monitored using a pictorial tool, Change Curve, which outlined the phases of organisational change. The project findings indicated that organisational change did not follow a clear linear trajectory. In some ways the dynamics mapped over a period of 18 months mirror the type of struggles individuals commonly encounter as a part of personal growth and development. In this case, one of the factors which influenced the program’s success was the willingness of executive employees to actively support and participate in the change management process. What is known about the topic? The pivotal role of community controlled organisations in the development of community based services and policy issues affecting Aboriginal and Torres Strait Islander Australians is well recognised. The presence and activities of these organisations reflects and contributes to community empowerment and self determination. Although it is possible to observe the effects of these organisations in communities, less attention has been given to empowerment as a concept to be utilised internally and as a resource to support wellbeing in the workplace. What does this paper add?In Australia, empowerment strategies are now accepted as an effective approach to health promotion and community development initiatives. This paper adds to this body of knowledge by considering the concept within the context of organisations in which an Indigenous worldview forms the foundation for action. What are the implications for practitioners?This article provides some preliminary insights into the how the concept of empowerment might be instigated in community controlled organisations. It also identifies some of the likely challenges and methodological issues to be considered in designing change management strategies in this context.