bluuebunny/crossref_metadata_2025 huggingface dataset:
COMMENTS ON NEUROECONOMICS
Authors: Rubinstein Ariel
Published: November 2008

Neuroeconomics is examined critically using data on the response times of subjects who were asked to express their preferences in the context of the Allais Paradox. Different patterns of choice are found among the fast and slow responders. This suggests that we try to identify types of economic agents by the time they take to make their choices. Nevertheless, it is argued that it is far from clear if and how neuroeconomics will change economics.
Will urbanization cause deforested areas to be abandoned in Brazilian Amazonia?
Authors: FEARNSIDE PHILIP M.
Published: November 2008

Wright and Muller-Landau (2006) proposed that rural–urban migration could reduce tropical forest loss worldwide and allow secondary forest to occupy abandoned clearings, thereby reducing the expected magnitude of tropical species extinctions. However, the usefulness of this global generalization is highly dependent on its being correct for Brazilian Amazonia, which has the world's largest remaining area of tropical forest. Among the features of the deforestation process that make urbanization an unlikely mechanism for land abandonment in Brazil is the fact that most deforestation is done by ranchers rather than by shifting cultivators. A family of shifting cultivators is only capable of farming a limited area and cannot greatly expand the area it cultivates if additional land becomes available. Ranchers, by contrast, can occupy huge areas and expand their holdings when the opportunity arises. Were part of the population to leave for the cities their land would usually be bought by neighbouring ranchers who would maintain and expand the deforested landscape. As Wright and Muller-Landau (2006) predicted, their interpretations have generated considerable controversy (Brook et al. 2006; Gardner et al. 2007; Laurance 2006; Sloan 2007). Only part of this controversy will be considered here, namely the expectation that rural population in tropical areas will decline, allowing secondary forests to regrow in large areas of abandoned farmland. Specifically, the present paper will consider the applicability of the Wright/Muller-Landau hypothesis to Brazilian Amazonia.
Transdisciplinary Aspects of Morphological Productivity
Authors: Dressler Wolfgang U.
Published: November 2008

This contribution presents a model of morphological productivity that allows some points of comparison with the concept of productivity in economics and in other disciplines. It is a two-step model: in the first step, degrees of productivity of morphological rules are established on the so-called syntagmatic axis of language, i.e. how a word is changed in its linear make-up, e.g. English boy becomes boy-s in the plural or is changed to boy-friend, boy-hood, boy-ish in word formation. In the second step, rule application is compared on the so-called paradigmatic axis with possibly competing productive rules, e.g. in adjective formation from nouns, suffixation with -ish (e.g. boy-ish), is compared with suffixations with -y (e.g. fier-y), -ly (e.g. friend-ly), -ic (e.g. syntact-ic), -ical (e.g. morpholog-ical). Then supportive psycholinguistic evidence is presented from online tests and first language acquisition, an area of crucial evidence for linguistic theories, since any constructs of a model must be learnable by children.
Influences of Central European Labour Migrants on their Western Employers
Authors: Goddeeris Idesbald
Published: November 2008

In matters of migration, it is not only the immigrants that are influenced by the new environment in their host country. The autochthonous population of the receiving country is affected by contact with the newcomers. This article analyses the impact of Polish domestic and construction workers on their employers in Leuven, a mid-size Belgian town. It shows that there was much more contact between employer and employee than one might have expected, despite the lack of a common language and the regular absence of the employer during the employee’s working hours. This contact led to the personalization of the anonymous mass of immigrants. New images arose, mostly very positive ones, and mostly related to the workplace. Old stereotypes did not disappear, but they were overshadowed by an awareness of particularities (clichés do not count for all Poles) and similarities (Poles have much in common with Belgians). In this way, the employment of Poles somehow stimulated a ‘Europeanization’ of sorts, and contributed towards developing a sense of common European features and values.
Building Language Competence in First Language Acquisition
Authors: Lieven Elena
Published: November 2008

Most accounts of child language acquisition use as analytic tools adult-like syntactic categories and grammars with little concern for whether they are psychologically real for young children. However, when approached from a cognitive and functional theoretical perspective, recent research has demonstrated that children do not operate initially with such abstract linguistic entities, but instead on the basis of distributional learning and item-based, form-meaning constructions. Children construct more abstract, linguistic representations only gradually on the basis of the language they hear and use and they constrain these constructions to their appropriate ranges of use only gradually as well – again on the basis of linguistic experience in which frequency plays a key role. Results from empirical analyses of children’s early multiword utterances, the development of the transitive construction and certain types of errors are presented to illustrate this approach.
Trust in the Everyday Life of Guests and Hosts: Employers and Employees in Belgium
Authors: Galent Marcin
Published: November 2008

The collapse of the Iron Curtain, and recent European enlargement have brought about new waves of intra-European migration. Whilst millions of people from Central and Eastern European countries have trodden the well-worn path to the West in search of better paid jobs, their migration trajectories have differed from traditional patterns. They very often work in host countries and simultaneously maintain close social links with their countries of origin, thus earning the label ‘pendulum migrants’. These pendulum movements can be perceived as agents that stimulate processes of social integration at the micro level. Contrary to popular discourse, which represents migration as a phenomenon endangering social cohesion, this article investigates how personal contacts between hosts and guests may contribute to the building of mutual trust between European citizens.
Immigration, the Welfare State and Working Life – the Case of Norway
Authors: Brochmann Grete
Published: November 2008

Today Western European welfare states find themselves in a paradoxical situation: parts of working life are in need of labour that is difficult to find nationally – and internationally. While this is partly due to inflexible policies, it is also due to competition for labour among Western countries. At the same time, asylum seekers are constantly arriving, often to be joined by family members. The authorities are confronted with a mismatch between the supply of, and demand for, immigrants. The receiving countries do not get the labour they want, while many of those who actually come cannot be incorporated productively for various reasons. This situation illustrates the squeeze facing today’s welfare states – in this article exemplified with the Norwegian case – between the logic of humanitarian responsibilities and the concerns of the national economy.
Antimicrobial use in food and companion animals
Authors: Prescott John F.
Published: November 2008

The vast literature on antimicrobial drug use in animals has expanded considerably recently as the antimicrobial resistance (AMR) crisis in human medicine leads to questions about all usage of antimicrobial drugs, including long-term usage in intensively managed food animals for growth promotion and disease prevention. Attention is also increasingly focusing on antimicrobial use and on bacterial resistance in companion animals, which are in intimate contact with the human population. They may share resistant bacteria with their owners, amplify resistant bacteria acquired from their owners, and act as a reservoir for human infection. Considerable effort is being made to describe the basis of AMR in bacterial pathogens of animals. Documentation of many aspects of use of antimicrobials in animals is, however, generally less developed and only a few countries can describe quantities of drugs used in animals to kg levels annually. In recent years, many national veterinary associations have produced ‘prudent use guidelines’ to try to improve antimicrobial drug use and decrease resistance, but the impact of guidelines is unknown. Within the evolving global movement for ‘antimicrobial stewardship’, there is considerable scope to improve many aspects of antimicrobial use in animals, including infection control and reduction of use, with a view to reducing resistance and its spread, and to preserving antimicrobial drugs for the future.
Antimicrobial resistance in beef and dairy cattle production
Authors: Call Douglas R. , Davis Margaret A. , Sawant Ashish A.
Published: November 2008

Observational studies of cattle production systems usually find that cattle from conventional dairies harbor a higher prevalence of antimicrobial resistant (AMR) enteric bacteria compared to organic dairies or beef-cow operations; given that dairies usually use more antimicrobials, this result is not unexpected. Experimental studies have usually verified that application of antimicrobials leads to at least a transient expansion of AMR bacterial populations in treated cattle. Nevertheless, on dairy farms the majority of antibiotics are used to treat mastitis and yet AMR remains relatively low in mastitis pathogens. Other studies have shown no correlation between antimicrobial use and prevalence of AMR bacteria including documented cases where the prevalence of AMR bacteria is non-responsive to antimicrobial applications or remains relatively high in the absence of antimicrobial use or any other obvious selective pressures. Thus, there are multi-factorial events and pressures that influence AMR bacterial populations in cattle production systems. We introduce a heuristic model that illustrates how repeated antimicrobial selection pressure can increase the probability of genetic linkage between AMR genes and niche- or growth-specific fitness traits. This linkage allows persistence of AMR bacteria at the herd level because subpopulations of AMR bacteria are able to reside long-term within the host animals even in the absence of antimicrobial selection pressure. This model highlights the need for multiple approaches to manage herd health so that the total amount of antimicrobials is limited in a manner that meets animal welfare and public health needs while reducing costs for producers and consumers over the long-term.
A method for prolonged imaging of motile lymphocytes
Authors: Day Daniel , Pham Kim , Ludford‐Menting Mandy J , Oliaro Jane , Izon David , Russell Sarah M , Gu Min
Published: November 2008

With new imaging technologies and fluorescent probes, live imaging of cells in vitro has revolutionized many aspects of cell biology. A key goal now is to develop systems to optimize in vitro imaging, which do not compromise the physiological relevance of the study. We have developed a methodology that contains non‐adherent cells within the field of view. ‘Cell paddocks’ are created by generating an array of microgrids using polydimethylsiloxane. Each microgrid is up to 250 × 250 μm2 with a height of 60 μm. Overlayed cells settle into the grids and the walls restrict their lateral movement, but a contiguous supply of medium between neighboring microgrids facilitates the exchange of cytokines and growth factors. This allows culture over at least 6 days with no impact upon viability and proliferation. Adaptations of the microgrids have enabled imaging and tracking of lymphocyte division through multiple generations of long‐term interactions between T lymphocytes and dendritic cells, and of thymocyte–stromal cell interactions.
Netrin-4 Enhances Angiogenesis and Neurologic Outcome after Cerebral Ischemia
Authors: Hoang Stanley , Liauw Jason , Choi Matthew , Choi Michael , Guzman Raphael G , Steinberg Gary K
Published: November 2008

Functional recovery after cerebral ischemia is mediated by the regeneration of vascular networks and the restoration of synaptic architecture. Netrins have been implicated in neuronal pathfinding and angiogenesis. In this study, we investigated the expression of Netrin-4 and its putative receptors, deleted in colorectal cancer (DCC), Unc5A, and Unc5B after distal middle cerebral artery occlusion in mice. Netrin-4 protein was also administered intracerebroventricularly to examine its effect on angiogenesis and behavioral recovery. Netrin-4 protein was highly upregulated in the ischemic core as soon as 1 day after cerebral ischemia, with subsequent downregulation after 1 week. Its expression was limited to the area of blood—brain barrier damage and was seen on both blood vessels and astrocytic foot processes. Although there was not a significant upregulation of the putative Netrin-4 receptor Unc5A and Unc5B, there was a significant increase in expression of the DCC receptor on neuronal processes in the peri-infarct cortex. Intracerebroventricular administration of Netrin-4 into the ischemic brain increased blood vessel density, endothelial proliferation, and improved behavioral recovery at 1 week after stroke, but did not have an effect on blood—brain barrier permeability or infarct size. These findings suggest that Netrin-4 may improve poststroke functional recovery by enhancing blood vessel proliferation.
Matrix Metalloproteinase-13 is Activated and is found in the Nucleus of Neural Cells after Cerebral Ischemia
Authors: Cuadrado Eloy , Rosell Anna , Borrell-Pagès Maria , García-Bonilla Lidia , Hernández-Guillamon Mar , Ortega-Aznar Arantxa , Montaner Joan
Published: November 2008

Matrix metalloproteinases (MMPs) have been implicated in the pathophysiology of ischemic stroke. In this study, we investigated the time course of gelatinolytic activation in a rat model of permanent ischemia. We observed an activation of MMPs as early as 30 mins after the ischemic insult, mainly in the nuclei of brain cells. Besides, we explored MMP-13 expression in brain samples of the animal model and stroke deceased patients. We observed an upregulation of active MMP-13 in rat brains ( P< 0.05) after 90 mins of cerebral ischemia. Human infarct/periinfarct samples also showed higher levels of active MMP-13 ( P< 0.05) compared with contralateral ones. Interestingly, we found that MMP-13 colocalized with 46-diamidino-2-phenyl indole signal by immunohistochemistry in both humans and rats, suggesting an intranuclear localization for MMP-13. Immunohistochemistry also revealed that MMP-13 was mainly produced by neurons, in both species, but also by oligodendrocytes in rats, and by astrocytes in humans. Finally we subjected a rat primary neuronal culture to oxygen and glucose deprivation (OGD) and we reproduced the nuclear translocation of MMP-13 in vitro. Nuclear extracts from cells confirmed upregulation of active MMP-13 after OGD ( P< 0.05). These results suggest that MMP-13 activation and its nuclear translocation is an early consequence of an ischemic stimulus.
A Physiologic Model for Recirculation Water Correction in CMRO2 Assessment with 15O2 Inhalation PET
Authors: Kudomi Nobuyuki , Hayashi Takuya , Watabe Hiroshi , Teramoto Noboru , Piao Rishu , Ose Takayuki , Koshino Kazuhiro , Ohta Youichirou , Iida Hidehiro
Published: November 2008

Cerebral metabolic rate of oxygen (CMRO2) can be assessed quantitatively using 15O2 and positron emission tomography. Determining the arterial input function is considered critical with regards to the separation of the metabolic product of 15O2 (RW) from a measured whole blood. A mathematical formula based on physiologic model has been proposed to predict RW. This study was intended to verify the adequacy of that model and a simplified procedure applying that model for wide range of species and physiologic conditions. The formula consists of four parameters, including of a production rate of RW ( k) corresponding to the total body oxidative metabolism (BMRO2). Experiments were performed on 6 monkeys, 3 pigs, 12 rats, and 231 clinical patients, among which the monkeys were studied at varied physiologic conditions. The formula reproduced the observed RW. Greater k values were observed in smaller animals, whereas other parameters did not differ amongst species. The simulation showed CMRO2 sensitive only to k, but not to others, suggesting that validity of determination of only k from a single blood sample. Also, k was correlated with BMRO2, suggesting that k can be determined from BMRO2. The present model and simplified procedure can be used to assess CMRO2 for a wide range of conditions and species.
Protective Role of Early Aquaporin 4 Induction against Postischemic Edema Formation
Authors: Hirt Lorenz , Ternon Béatrice , Price Melanie , Mastour Nabil , Brunet Jean-François , Badaut Jérôme
Published: November 2008

Aquaporin 4 (AQP4) is a water channel involved in water movements across the cell membrane and is spatially organized on the cell surface in orthogonal array particles (OAPs). Its role in edema formation or resolution after stroke onset has been studied mainly at late time points. We have shown recently that its expression is rapidly induced after ischemia coinciding in time with an early swelling of the ischemic hemisphere. There are two isoforms of AQP4: AQP4-M1 and AQP4-M23. The ratio of these isoforms influences the size of the OAPs but the functional impact is not known. The role of the early induction of AQP4 is not yet known. Thrombin preconditioning in mice provides a useful model to study endogenous protective mechanisms. Using this model, we provide evidence for the first time that the early induction of AQP4 may contribute to limit the formation of edema and that the AQP4-M1 isoform is predominantly induced in the ischemic tissue at this time point. Although it prevents edema formation, the early induction of the AQP4 expression does not prevent the blood—brain barrier disruption, suggesting an effect limited to the prevention of edema formation possibly by removing of water from the tissue.
Improvement in the suspension‐culture production of recombinant adeno‐associated virus–LacZ in HEK‐293 cells using polyethyleneimine–DNA complexes in combination with hypothermic treatment
Authors: Feng Lei , Guo Meijin , Zhang Shuxiang , Chu Ju , Zhuang Yingping , Zhang Siliang
Published: November 2008

rAAV (recombinant adeno‐associated virus) has become a very useful gene‐delivery vector for gene therapy. However, it is very difficult to generate rAAV using triple transfection on a commercial scale, owing to its low transfection efficiency. An optimal procedure for transfection in suspension‐culture mode was developed for rAAV–LacZ production in suspension‐cultured HEK‐293 (human embryonic kidney‐293) cells mediated by PEI (polyethyleneimine)–DNA complexes in combination with transient severe hypothermia at 4 °C for 1 h in the present study (LacZ is the product of the reporter gene lacZ, which codes for β‐d‐galactosidase). It showed that the PEI/DNA ratio, cell density at the beginning of transfection and cell‐cycle arrest in G2/M‐phase were key factors affecting suspension‐culture triple‐transfection efficiency and rAAV–LacZ productivity. After incubation at 4 °C for 1 h and re‐warming at 37 °C for 18 h, HEK‐293 cells at 1×106 cells/ml were transfected with PEI–DNA complexes at a PEI/DNA ratio of 5:1 (w/w) with final concentrations of 30 μg/ml 25 kDa linear PEI and 6 μg/ml plasmid DNA in culture. After 6 h incubation for transfection, an equal volume of medium was added to the culture for additional 48 h growth until harvest. Finally, the high transfection efficiency of some 75% and rAAV–LacZ titre of (7.48±0.59)×1011 physical particles or 1.86±0.96×1010 infectious particles were achieved in 250 ml shake flasks with 60 ml working volume, indicating a promising application for scale‐up.
Down‐regulation of layilin, a novel hyaluronan receptor, via RNA interference, inhibits invasion and lymphatic metastasis of human lung A549 cells
Authors: Chen Zhengtang , Zhuo Wenlei , Wang Yan , Ao Xujun , An Jianghong
Published: November 2008

Human lung carcinoma is a highly metastatic tumour that leads to a high death rate and in which lymphatic metastasis is an important early event. HYA (hyaluronan) is involved in the invasion of a variety of tumour cells. Layilin, a specific and novel HYA receptor, was detected in the human lung cell line A549 in our preliminary research, and was hypothesized to play an essential role in cell motility and tumour lymphatic metastasis. In the present study we found that, as expected, suppression of layilin expression by RNA interference significantly inhibited A549‐cell invasion and migration in vitro and lymphatic metastasis in vivo and thereby resulted in the increased survival of tumour‐bearing mice. These findings suggested that layilin might play crucial roles in lymphatic metastasis of lung carcinoma and that suppression of layilin expression might be a promising strategy for treatment of human lung carcinoma.
Structural analysis of a glycoside hydrolase family 43 arabinoxylan arabinofuranohydrolase in complex with xylotetraose reveals a different binding mechanism compared with other members of the same family
Authors: Vandermarliere Elien , Bourgois Tine M. , Winn Martyn D. , van Campenhout Steven , Volckaert Guido , Delcour Jan A. , Strelkov Sergei V. , Rabijns Anja , Courtin Christophe M.
Published: November 2008

AXHs (arabinoxylan arabinofuranohydrolases) are α-L-arabinofuranosidases that specifically hydrolyse the glycosidic bond between arabinofuranosyl substituents and xylopyranosyl backbone residues of arabinoxylan. Bacillus subtilis was recently shown to produce an AXH that cleaves arabinose units from O-2- or O-3-mono-substituted xylose residues: BsAXH-m2,3 (B. subtilis AXH-m2,3). Crystallographic analysis reveals a two-domain structure for this enzyme: a catalytic domain displaying a five-bladed β-propeller fold characteristic of GH (glycoside hydrolase) family 43 and a CBM (carbohydrate-binding module) with a β-sandwich fold belonging to CBM family 6. Binding of substrate to BsAXH-m2,3 is largely based on hydrophobic stacking interactions, which probably allow the positional flexibility needed to hydrolyse both arabinose substituents at the O-2 or O-3 position of the xylose unit. Superposition of the BsAXH-m2,3 structure with known structures of the GH family 43 exo-acting enzymes, β-xylosidase and α-L-arabinanase, each in complex with their substrate, reveals a different orientation of the sugar backbone.
Time course of changes in serum oxidant/antioxidant status in overfed obese rats and their offspring
Authors: Bouanane Samira , Benkalfat Nassira B. , Baba Ahmed Fatima-Zohra , Merzouk Hafida , Mokhtari Nassima S. , Merzouk Sid-Ahmed , Gresti Joseph , Tessier Christian , Narce Michel
Published: November 2008

The aim of the present study was to determine the time course of changes in oxidant/antioxidant status, as well as serum glucose, insulin, leptin and lipid levels, liver adipose tissue and muscle lipid and protein contents, in cafeteria-diet-fed dams during gestation and lactation, and in their offspring throughout adulthood. Food intake was also evaluated. The cafeteria diet induced a significant increase in maternal body and relative adipose tissue weights, daily energy intake, and plasma glucose, insulin, leptin and lipid levels at parturition (day 0) and at the end of lactation (day 21). Plasma total antioxidant status [ORAC (oxygen radical absorbance capacity)], erythrocyte catalase and SOD (superoxide dismutase) activities were lower, whereas plasma hydroperoxide and carbonyl protein levels were higher in cafeteria-diet-fed mothers compared with control mothers at days 0 and 21. Pups from cafeteria-diet-fed dams, both males and females, also had consistently higher body and relative adipose tissue weights, and plasma glucose, insulin, leptin, triacylglycerol (triglyceride) and cholesterol levels at birth (day 0), weaning (day 21) and 3 months of age (day 90). These offspring had significantly lower ORAC and catalase activity, and higher plasma hydroperoxide and carbonyl protein levels and SOD activity at birth, at days 21 and 90 compared with control offspring. In conclusion, excessive maternal fat and energy intake can play an important role in the development of metabolic disorders in the offspring. Maternal oxidative stress may be among the responsible factors. Fetal oxidative stress may present an additional confounding influence and probably contributes to additional disorders, aggravating features of the metabolic syndrome. An improvement in maternal oxidant/antioxidant status during pregnancy and lactation, with adequate nutrition, could have beneficial effects on the progeny.
Employing Latino Value Orientations to Facilitate Success in Stuttering Treatment
Authors: Ramos-Heinrichs Lourdes , Mayo Lynn Hansberry , Garzon Sandra
Published: November 2008

Providing adequate speech therapy services to Latinos who stutter can present challenges that are not obvious to the practicing clinician. This article addresses cultural, religious, and foreign language concerns to the therapeutic relationship between the Latino client and the clinician. Suggestions are made for building cross-cultural connections with clients and incorporating the family into a collaborative partnership with the service provider.
Picosecond laser structuration under high pressures: Observation of boron nitride nanorods
Authors: Museur Luc , Petitet Jean-Pierre , Michel Jean-Pierre , Marine Wladimir , Anglos Demetrios , Fotakis Costas , Kanaev Andrei V.
Published: November 2008

We report on picosecond UV-laser processing of hexagonal boron nitride (BN) at moderately high pressures above 500 bar. The main effect is specific to the ambient gas and laser pulse duration in the ablation regime: when samples are irradiated by 5 or 0.45 ps laser pulses in nitrogen gas environment, multiple nucleation of a new crystalline product-BN nanorods-takes place. This process is triggered on structural defects, which number density strongly decreases upon recrystallization. Nonlinear photon absorption by adsorbed nitrogen molecules is suggested to mediate the nucleation growth. High pressure is responsible for the confinement and strong backscattering of ablation products. A strong surface structuring also appears at longer 150 ps laser irradiation in similar experimental conditions. However, the transformed product in this case is amorphous strongly contaminated by boron suboxides BxOy.
Photodissociation of ClN3 at 157 nm: Theory suggests a pathway leading to cyclic N3
Authors: Kerkines Ioannis S. K. , Wang Zhi , Zhang Peng , Morokuma Keiji
Published: November 2008

The photodissociation dynamics of chlorine azide (ClN3) at the 157 nm region was studied theoretically using the multireference configuration interaction method and the complete active space self-consistent field direct dynamics method. The excitation at the 157 nm region was assigned to the 4 A1′(S7)←X̃ A1′(S0) transition. A likely pathway for the formation of cyclic N3 after this transition was identified by direct dynamics as follows: ClN3 excited to 4 A1′(S7) dissociates after about 40 fs to excited N3(2 A2′, with about 44 kcal/mol internal energy) +Cl(P2). This vibrationally hot N3(2 A2′) goes diabatically through a conical intersection with N3(1 A2′) at 44 fs onto 1 A2′. At 19 fs later and repeatedly after every 55 fs, N3(1 A2′) crosses and trickles down via Coriolis coupling to N3(2 A2″/ B21) state, which has a potential minimum at the cyclic-N3 structure. Some fraction of N3(2 A2″/ B21) produced will survive dissociation and will be found as the cyclic N3, and some other fraction will eventually dissociate to N(D2)+N2 over a high barrier found previously.
Digging a hole: Scaled-particle theory and cavity solvation in organic solvents
Authors: Jain Amit , Ashbaugh Henry S.
Published: November 2008

A recent extension of scaled-particle theory for cavity solvation in polyatomic solvents developed by Ashbaugh and Pratt [J. Phys. Chem. B 111, 9330 (2007)] is tested against molecular simulations of 13 organic liquids. This molecular scaled-particle theory incorporates the intramolecular structure of the solvent in the calculation of the cavity excluding volume, compared with traditional applications of scaled-particle theory where the solvent is treated as an individual hard sphere with no internal structure. Once the diameters of the constituent carbon interaction sites are specified, molecular scaled-particle theory is able to discriminate between geometrically distinct solvents and provides accurate predictions for cavity solvation free energies and near quantitative predictions of the cavity contact correlation function. The diameters of the solvent interaction sites are argued to be transferable between related groups on different solvents, leading to a truly predictive scaled-particle theory given only information on the solvent pressure, density, and molecular topology.
Flexible Cu(In,Ga)Se2 solar cells fabricated using alkali-silicate glass thin layers as an alkali source material
Authors: Ishizuka Shogo , Yamada Akimasa , Fons Paul , Niki Shigeru
Published: November 2008

Flexible Cu(In,Ga)Se2 (CIGS) solar cells were fabricated using alkali-silicate glass thin layers (ASTL) as an alkali source material deposited on various flexible substrates prior to the Mo backcontact layer deposition. Control of univalent alkali metal incorporation into the CIGS layer with the use of ASTL was demonstrated regardless of the presence of other multivalent metal impurities in ASTL. Dramatic enhancement in cell efficiencies using ASTL was observed though the use of excessively thick ASTL led to a degradation in cell performance. The quantum efficiency curves of CIGS solar cells fabricated using ASTL showed enhanced absorption in the long wavelength region. The photovoltaic performance dependence on a variety of substrate materials is also discussed.
Suppression of defect states in HfSiON gate dielectric films on n-type Ge(100) substrates
Authors: Chung K. B. , Seo H. , Long J. P. , Lucovsky G.
Published: November 2008

Defect states in HfO2 and HfSiON films deposited on Ge(100) substrates were studied by spectroscopic ellipsometry (SE) and x-ray absorption spectroscopy (XAS). In addition, structural and compositional changes in these films were examined via medium energy ion scattering (MEIS). SE and XAS experiments revealed two distinct band edge defect states, located at 1.7±0.1eV and at 2.7±0.1 below the conduction band edges of these films. The number of defect states in HfO2 increased noticeably following postdeposition annealing (PDA), whereas in HfSiON, it showed only small increases following the same treatment. MEIS measurements showed that Ge diffusion into HfO2 films was enhanced significantly by PDA as well; however, this effect was less pronounced in the HfSiON films. The suppression of defect state enhancement in HfSiON films was correlated with lower levels of Ge diffusion and increased structural stability with respect to HfO2.
Theoretical studies of potential energy surface and rotational spectra of Xe–H2O van der Waals complex
Authors: Wang Lin , Yang Minghui
Published: November 2008

In this work we report an ab initio intermolecular potential energy surface and theoretical spectroscopic studies for Xe–H2O complex. The ab initio energies are calculated with CCSD(T) method and large basis sets (aug-cc-pVQZ for H and O and aug-cc-pVQZ-PP for Xe) augmented by a {3s3p2d2f1g} set of bond functions. This potential energy surface has a global minimum corresponding to a planar and nearly linear hydrogen bonded configuration with a well depth of 192.5cm−1 at intermolecular distance of 4.0Å, which is consistent with the previous determined potential by Wen and Jäger [J. Phys. Chem. A 110, 7560 (2006)]. The bound state calculations have been performed for the complex by approximating the water molecule as a rigid rotor. The theoretical rotational transition frequencies, isotopic shifts, nuclear quadrupole coupling constants, and structure parameters are in good agreement with the experimental observed values. The wavefunctions are analyzed to understand the dynamics of the ground and the first excited states.
A plasma model combined with an improved two-temperature equation for ultrafast laser ablation of dielectrics
Authors: Jiang Lan , Tsai Hai-Lung
Published: November 2008

It remains a big challenge to theoretically predict the material removal mechanism in femtosecond laser ablation. To bypass this unresolved problem, many calculations of femtosecond laser ablation of nonmetals have been based on the free electron density distribution without the actual consideration of the phase change mechanism. However, this widely used key assumption needs further theoretical and experimental confirmation. By combining the plasma model and improved two-temperature model developed by the authors, this study focuses on investigating ablation threshold fluence, depth, and shape during femtosecond laser ablation of dielectrics through nonthermal processes (the Coulomb explosion and electrostatic ablation). The predicted ablation depths and shapes in fused silica, by using (1) the plasma model only and (2) the plasma model plus the two-temperature equation, are both in agreement with published experimental data. The widely used assumptions for threshold fluence, ablation depth, and shape in the plasma model based on free electron density are validated by the comparison study and experimental data.
Deep-depletion breakdown of Johnsen–Rahbek type electrostatic chuck operation for semiconductor processes
Authors: Qin Shu , McTeer Allen
Published: November 2008

Johnsen–Rahbek type (JR type) electrostatic chuck (ESC) was found to be more sensitive to wafer conditions than classic ESC, including backside dielectric quality and thickness, wafer type, and doping level. Wafer type and doping level may significantly affect the reliability of ESC operations, depending on ESC configurations and operation conditions. Deep-depletion breakdown phenomenon of a JR type ESC operation, which is equivalent to a metal-insulator-semiconductor capacitor, was simulated by PISCES-IIB device simulator, and it was found to be a mechanism of the reliability and pop-off issues of JR type ESC operations. In this paper, the potential solutions are proposed to solve these issues.
Large electro-optic effect in single-crystal Pb(Zr,Ti)O3 (001) measured by spectroscopic ellipsometry
Authors: Kang Tae Dong , Xiao Bo , Avrutin Vitaliy , Özgür Ümit , Morkoç Hadis , Park Jun Woo , Lee Ho Suk , Lee Hosun , Wang Xiaoyu , Smith David. J.
Published: November 2008

Using spectroscopic ellipsometry electro-optic effect was studied in lead zirconate titanate (PZT) thin films grown epitaxially on Nb-doped SrTiO3(001) substrates by RF magnetron sputtering. A uniaxial multilayer model analysis was applied to extract the linear and quadratic electro-optic coefficients from the shifts in the ordinary and extraordinary refractive indices with electric field applied along the (001) direction. The effective linear and quadratic coefficients were measured as −134.6×10−12 m/V and 8.5×10−18 m2/V2, respectively, at a wavelength of 632.8 nm, while the individual linear electro-optic coefficients r33 and r13 were −157.1 and 22 pm/V, respectively. The existence of the linear electro-optic effect in unpoled PZT films was attributed to the presence of a built-in polarization and simultaneous poling during measurements.
High power light-emitting diode junction temperature determination from current-voltage characteristics
Authors: Keppens A. , Ryckaert W. R. , Deconinck G. , Hanselaer P.
Published: November 2008

Optical and electrical characteristics of power light-emitting diodes (LEDs) are strongly dependent on the diode junction temperature. However, direct junction temperature determination is not possible and alternative methods must be developed. Current-voltage characteristics of commercial high power LEDs have been measured at six different temperatures ranging between 295 and 400 K. Modeling these characteristics, including variation in the bandgap with temperature, revealed a linear temperature dependence of the forward voltage if the drive current is chosen within a rather limited current range. Theoretically, the voltage intercept can be deduced from the bulk semiconductor bandgap. However, accurate junction temperature determination is only possible if at least two calibration measurements at a particular drive current are performed. The method described in this paper can be applied to calculate the thermal resistance from the junction to any other reference point for any particular LED configuration.
Design and application of a mechanical load frame for in situ investigation of ferromagnetic shape memory alloys by magnetic force microscopy
Authors: Niklasch D. , Maier H. J. , Karaman I.
Published: November 2008

An in situ mechanical load frame has been developed for a commercially available atomic force microscope. This frame allows examining changes in topography and magnetic domain configuration under a given constant load or strain. First results obtained on Ni–Mn–Ga ferromagnetic shape memory alloy single crystals are presented. The magnetic force microscopy (MFM) measurements under different strain levels confirm the one-to-one correspondence, i.e., the magnetomicrostructural coupling between the martensite twins and the magnetic domains. Additionally, the growth of the twin variant with favorable orientation to the compression axis during martensite detwinning was observed. It will be shown that this load frame can be used for the investigation of the relationship between the microstructure and the magnetic domain structure in ferromagnetic shape memory alloys by MFM.
Organic cesium salt as an efficient electron injection material for organic light-emitting diodes
Authors: Xie Kai , Qiao Juan , Duan Lian , Li Yang , Zhang Deqiang , Dong Guifang , Wang Liduo , Qiu Yong
Published: November 2008

Cesium quinoline-8-oxide (Csq), as an organic salt, was synthesized and applied as an electron injection material for organic light-emitting diodes. A typical bilayer structure of N,N′-bis-(1-naphthyl)-N,N′-diphenyl-1,1′-biphenyl-4,4′-diamine/tris-(8-hydroxy-quinolinolato) aluminum (III) (Alq3) was used to evaluate the electron injection of Csq. The results showed Csq/Al had better electron injection than LiF/Al cathode, and a maximum current efficiency of 4.13 cd/A (3.33 cd/A for LiF/Al) was obtained when the Csq layer is 2.0 nm. It is proposed that the enhanced electron injection by Csq is related to the interfacial chemical reaction between Csq and Al and the self-doping of Csq by librated Cs.
Metal-metal terahertz quantum cascade laser with micro-transverse-electromagnetic-horn antenna
Authors: Maineult Wilfried , Gellie Pierre , Andronico Alessio , Filloux Pascal , Leo Giuseppe , Sirtori Carlo , Barbieri Stefano , Peytavit Emilien , Akalin Tahsin , Lampin Jean-Francois , Beere Harvey E. , Ritchie David A.
Published: November 2008

A 2.8 THz metal-metal quantum cascade laser operating with a microtransverse-electromagnetic-horn antenna has been demonstrated. By comparing the far-field radiation pattern to a standard ridge cavity with a cleaved facet, a striking improvement of the directionality is observed. The effectiveness of the horn antenna is critically dependent on the control of the lateral modes in the laser cavity.
Topological peculiarities in liquid phase of styrene butadiene rubber thin films induced by electrostatic nanolithography
Authors: Rackaitis Mindaugas , Kashyn Dmytro , Hirano Tadashi , Lyuksyutov Sergei F.
Published: November 2008

Nanostructures of 50–200nm in width were formed in styrene butadiene rubber using atomic force microscopy electrostatic nanolithography combined with vertical manipulation of the tip. The formation of circular nanostructures is attributed to factors such as the strength of the electric field (109–1010Vm−1), a contribution to the radial component of the pressure gradient, and a film thickness of less than 10nm. Stability of the features (48h) suggests cross-linking between macromolecules at the nanoscale.
Low density InAs quantum dots with control in energy emission and top surface location
Authors: Alonso-González P. , Fuster D. , González L. , Martín-Sánchez J. , González Y.
Published: November 2008

In this work we extend the droplet epitaxy growth technique to the fabrication of low density InAs quantum dots (QDs) on GaAs (001) substrates with control in size, energy emission, and top surface location. In particular, depending on the amount of InAs material deposited, it has been possible to tune the QD energy emission over a range of 1.12–1.40 eV while keeping constant the nanostructures density at 2×108 cm−2. Moreover, the capping growth process of these QD shows mounding features that permit their spatial identification once embedded by a GaAs capping layer.
The effect of electrode heat sink in organic-electronic devices
Authors: Choi Sang Hun , Lee Tae Il , Baik Hong Koo , Roh Hee Hwan , Kwon Ohmyoung , Suh Dong hak
Published: November 2008

Most of organic devices showed poor thermal stability and short lifetime due to Joule heating by current injection during operation. To increase the lifetime of the devices, thermal management must be considered. We demonstrated the polymer light-emitting diodes with thermally conductive substrate and Al/Cu double cathode to enhance the thermal stability of the device. Also, we proposed the correlation between lifetime (Δt) and device heat sink (ΔT). The heat sink of all organic devices is required to enhance device durability.
Positions without Negations? Dialectical Reason and the Contingencies of Space
Authors: Collinge Chris
Published: November 2008

The dialectical tradition that derives from Hegel and Marx has been very influential within social science, flowing into human geography from the early 1970s through the work of Lefebvre and Harvey. In their different ways these two scholars sought to extend dialectical logic to encompass the contingencies of space, and it is in this context that their seminal contributions to scale analysis can be understood. Since the 1980s, however, confidence in the dialectical tradition has been undermined by poststructural philosophers such as Derrida—who (whilst being careful to avoid simply negating Hegelian dialectics) has exposed the nontotalisable structure of contingency that both subtends and subverts dialectical reason. In this paper I draw upon Derrida's treatment of contingency, and explore the nondialectical ‘foundations’ of dialectical logic through a reading of Neil Smith's 1984 book on Uneven Development (Blackwell, Oxford), a classic text from Marxist geography which was the first to articulate a fully theorised scale framework.
Dialectics and the Measure of the World
Authors: Elden Stuart
Published: November 2008

This ‘afterword’ to the papers on dialectics situates the debate in the ground between Marxism and poststructuralism. Rather than a wholesale rejection of the dialectic, these authors attempt to think how poststructuralism might force an encounter with it, retaining yet transforming it. Drawing on Deleuze's characterization of abstract thought as dealing with concepts that “like baggy clothes, are much too big”, and Bergson's complaint that dialectics are “too large … not tailored to the measurements of the reality in which we live”, the paper moves to thinking about the relation of dialectics, measure, and world. It does so through an interrogation of a nondialectical materialism, that of Alain Badiou and his ex-student Quentin Meillassoux, particularly Meillassoux's critique of correlationism. One of the key issues raised is the return of mathematics, and its embrace within some aspects of human geography. Raising the question of how this may reverse some of the gains of poststructuralism and Marxism in combating the reduction of the quantitative revolution, the paper concludes by asking if geography is really willing to accept mathematical ordering, not merely in terms of a way of understanding the world, but as a suggestion that this is how the world actually is.
Towards a Dialectics of the Positive
Authors: Ruddick Sue
Published: November 2008

The persistent divide within French philosophy between so-called structuralists and poststructuralists has been recently revived in the writings of Badiou and others. This narration of the history of French philosophy is trapped inevitably in the very way it poses the problem: as a dialectic of the negative. The abstracting of these traditions from all their messiness into a dialectical opposition is itself part of the problem, a misrepresentation, ignoring any points of convergence. Drawing centrally on the work of Pierre Macherey, I suggest this divide can be traced back to Hegel's profound misreading of Spinoza, which became the basis for Hegel's dialectic and Marx's subsequent inversion. I explore crucial points of convergence between Marx and Spinoza, and a resonance between Deleuze and Macherey (who are often stereotyped as emblems of oppositional tendencies within French philosophy). Their work converges on a rejection of negation as the defining quality of essence or multiplicity and, in the case of Deleuze and Macherey, a shared uptake of Spinoza's concept of potentia. Their work gestures towards the development of a dialectics of the positive: a problematic that might enable us to think across our differences to a political ontology that embraces the posthuman, immanent, and affirmative qualities of struggle.
Alum (KAl(SO4)2·12H2O)-Catalyzed, Eco-Friendly, and Efficient One-Pot Synthesis of 2-Arylbenzothiazoles and 2-Arylbenzoxazole in Aqueous Medium
Authors: Pawar Shivaji S. , Dekhane Deepak V. , Shingare Murlidhar S. , Thore Shivaji N.
Published: November 2008

Alum (KAl(SO4)2·12H2O) performs as a novel catalyst for the synthesis of 2-arylbenzothiazoles and 2-arylbenzoxazole from o-aminothiophenol and o-aminophenol with various substituted aldehydes in good to excellent isolated yields (85–95%) using water as a solvent at ambient temperature. Several solvents were examined for this reaction; however, in terms of reaction yield and time, water was found to be the optimum solvent. The remarkable advantages offered by this method are an inexpensive and easily available catalyst, a simple procedure, mild conditions, much faster (60–90 min) reactions, and good to excellent yields of products.
One-Pot Synthesis of 2-Substituted Benzoxazoles Directly from Carboxylic Acids
Authors: Kumar Dinesh , Rudrawar Santosh , Chakraborti Asit K.
Published: November 2008

Methanesulfonic acid has been found to be a highly effective catalyst for a convenient and one-pot synthesis of 2-substituted benzoxazoles by the reaction of 2-aminophenol with acid chlorides, generated in situ from carboxylic acids. Aryl, heteroaryl, and arylalkyl carboxylic acids provided excellent yields of the corresponding benzoxazoles. The reaction conditions were compatible with various substituents such as chloro, bromo, nitro, methoxy, cyclopentyloxy, phenoxy, thiophenoxy, and conjugated double bonds. Benzoxazole formation was found to be general with respect to substituted 2-aminophenols.