bluuebunny/crossref_metadata_2025 huggingface dataset:
IL‐6 promotes malignant growth of skin SCCs by regulating a network of autocrine and paracrine cytokines
Authors: Lederle Wiltrud , Depner Sofia , Schnur Sabine , Obermueller Eva , Catone Nicola , Just Alexandra , Fusenig Norbert E. , Mueller Margareta M.
Published: August 2010

Cytokines play a crucial role in tumor initiation and progression. Here, we demonstrate that interleukin (IL)‐6 is a key factor by driving tumor progression from benign to malignant, invasive tumors in the HaCaT‐model of human skin carcinoma. IL‐6 activates STAT3 and directly stimulates proliferation and migration of the benign noninvasive HaCaT‐ras A‐5 cells in vitro. Furthermore, IL‐6 induces a complex, reciprocally regulated cytokine network in the tumor cells that includes inflammatory and angiogenic factors such as IL‐8, GM‐CSF, VEGF and MCP‐1. These IL‐6 effects lead to tumor cell invasion in organotypic cultures in vitro and to the formation of malignant and invasive s.c. tumors in vivo. Tumor invasion is supported by the IL‐6 induced overexpression of MMP‐1 in vitro and in vivo. These data demonstrate a key function of IL‐6 in the progression of skin SCCs by regulating a complex cytokine and protease network and suggest new therapeutic approaches to target this central player in skin carcinogenesis.
Degradation of Poly(butyl acrylate) and Poly(2‐hydroxyethyl methacrylate) Model Compounds Under Extreme Environmental Conditions
Authors: Bennet Francesca , Barker Philip J. , Davis Thomas P. , Soeriyadi Alexander H. , Barner‐Kowollik Christopher
Published: August 2010

The degradation of low‐MW ($\overline {M} _{n} $ = 1 500 g · mol−1) model compounds of pBA and pHEMA were studied under conditions corresponding to the worst‐case temperatures and irradiation intensities likely to be experienced by a surface coating exposed to the harsh Australian environment. Vinyl‐terminated polymers were compared to their saturated analogues; the terminal vinyl bond was found to be a source of instability which rendered the polymers more susceptible to degradation. The cyclic degradation mechanism derived from degradation of pMMA in our previous publication is also relevant to pBA and pHEMA. In addition, pBA and pHEMA are susceptible to other degradation and crosslinking reactions; crosslinking is particularly rapid in pHEMA exposed to UV radiation.

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Structure‐based prediction of protein–peptide specificity in rosetta
Authors: King Christopher A. , Bradley Philip
Published: August 2010

Protein–peptide interactions mediate many of the connections in intracellular signaling networks. A generalized computational framework for atomically precise modeling of protein–peptide specificity may allow for predicting molecular interactions, anticipating the effects of drugs and genetic mutations, and redesigning molecules for new interactions. We have developed an extensible, general algorithm for structure‐based prediction of protein–peptide specificity as part of the Rosetta molecular modeling package. The algorithm is not restricted to any one peptide‐binding domain family and, at minimum, does not require an experimentally characterized structure of the target protein nor any information about sequence specificity; although known structural data can be incorporated when available to improve performance. We demonstrate substantial success in specificity prediction across a diverse set of peptide‐binding proteins, and show how performance is affected when incorporating varying degrees of input structural data. We also illustrate how structure‐based approaches can provide atomic‐level insight into mechanisms of peptide recognition and can predict the effects of point mutations on peptide specificity. Shortcomings and artifacts of our benchmark predictions are explained and limits on the generality of the method are explored. This work provides a promising foundation upon which further development of completely generalized, de novo prediction of peptide specificity may progress. Proteins 2010. © 2010 Wiley‐Liss, Inc.
DFT calculations for the heterojunction effect between metal clusters and the stabilizer molecules
Authors: Okumura Mitsutaka , Kitagawa Yasutaka , Kawakami Takashi
Published: August 2010

Lately, liquid phase catalytic reactions over quasi heterogeneous catalysts, whose active site are stabilized by polymers, dendorimers, and soforth, are reported. It is well known that the heterojunction between the metal clusters and the metal oxide supports is important factor for the generation of catalytic activities of the heterogeneous catalysts, such as the metal oxide‐supported Au catalysts. However, there is no metal oxide supports in the quasi heterogeneous catalysts. Therefore, we investigate the difference between the bare cluster and the polymer stabilized clusters using hybrid density functional theory. From the calculation results, it was found that the charge transfer interaction between the stabilizing molecules and the cluster plays an important role to exhibit the catalytic activities of the quasi heterogeneous catalysts. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2010
Kernel energy method: Drug–target interaction energies for drug design
Authors: Huang Lulu , Massa Lou
Published: August 2010

The full power of ab initio quantum mechanics applied to obtain the interaction of drugs and their molecular targets can provide detailed energetics useful to understanding of mechanism and drug design. The computational problem is the growth in quantum computational difficulty with the number of atoms in the molecule. As biochemical molecules are often large, the computational difficulty of the full quantum problem is challenging. Two things help alleviate the difficulty, viz., (1) parallel supercomputers, and (2) quantum crystallography and the use of quantum kernels, a method well suited for parallel computation. Calculations are simplified by approximating a full molecule by smaller “kernels” of atoms. Here, it is suggested that problems of medicinal chemistry, such as the rational design of drugs, may be illuminated by the use of the ab initio quantum‐mechanical kernel energy method. Example calculations within the MP2/3‐21G chemical model are illustrated for three aminoglycoside drugs, which attach to ribosomal A‐site RNA nucleotide targets. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2010
Quantum chemical study of the energetics and directionality of acid‐catalyzed aromatic epoxide ring openings
Authors: Korzan Rory , Upton Brian , Turnbull Kenneth , Seybold Paul G.
Published: August 2010

Epoxide ring openings play important roles in a variety of chemical situations and are believed to be important in the metabolic processes through which some polycyclic aromatic hydrocarbons are converted to carcinogenic species. In this report, the energetics and directionalities of acid‐catalyzed epoxide ring openings in benzene and naphthalene are examined using quantum chemical (MNDO/d and MP2/6‐31G*) methods. In particular, the consequences of local saturations in the aromatic systems are examined and shown to exert strong influences on the resulting energetics and product distributions. Partial ring saturation in an aromatic system leads to barrier‐free, spontaneous ring opening of the protonated epoxide in a favored direction and eliminates opening in the opposite direction. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2010
Pathological, immunological and biochemical markers of subchronic arsenic toxicity in rats
Authors: Nain Sukhbir , Smits Judit E. G.
Published: August 2010

Subchronic exposure to arsenic in rats was investigated to identify sensitive indicators of subclinical toxicity in rats. Immunological, pathological, and biochemical bioindicators were examined in rats exposed to arsenic in their drinking water. Juvenile male Wistar rats were allocated to four treatment groups receiving 0, 0.4, 4, and 40 ppm of arsenite in drinking water for 18 wks. Besides daily monitoring for clinical signs of adverse health effects, clinical biochemistry, B‐cell‐mediated and innate immune responses, plus gross, and histopathology were examined. In vitro tests of oxidative damage to basic cellular constituents, lipids, proteins, and nucleic acids, were measured using thiobarbituric acid reacting substances (TBARS) assays, protein carbonyl formation, and 8‐hydroxydeoxyguanosine (8‐OHdG), respectively. Clinical changes in the rats were limited to decreased feed and water intake in the high‐ (40 ppm) dose group (P < 0.05), however, growth rate was not affected. Serum biochemical changes occurred in blood urea nitrogen, K+, Cl−, and alanine aminotransferase (ALT) from arsenic exposure. Immunotoxicity was evident through a dose‐dependent suppression of the secondary antibody‐mediated response to a T‐cell‐dependent antigen, keyhole limpet hemocyanin (KLH). Histopathology of the liver revealed marked fatty infiltration and vacuolization particularly evident in periacinar hepatocytes. This pattern of toxicopathology in the high‐exposure group may be related to the significantly higher (P < 0.05) oxidative stress, demonstrated through lipid peroxidation (TBARS assay) in the rats exposed to 40 ppm arsenite. The present study revealed that young, growing rats exposed to arsenic for 18 wks tolerated exposures up to 4 ppm. At higher doses, there was evidence of hepatotoxicity, humoral immunity was compromised, and an adverse effect on hepatic organelle and cell membranes was evident through a dose dependent increased in oxidative stress. © 2010 Wiley Periodicals, Inc. Environ Toxicol, 2012.
Chronic contamination assessment integrating biomarkers' responses in transplanted mussels—A seasonal monitoring
Authors: Pereira C. D. S. , Martín‐Díaz M. L. , Catharino M. G. M. , Cesar A. , Choueri R. B. , Taniguchi S. , Abessa D. M. S. , Bícego M. C. , Vasconcellos M. B. A. , Bainy A. C. D. , Sousa E. C. P. M. , DelValls T. A.
Published: August 2010

This study aimed to provide the first biomonitoring integrating biomarkers and bioaccumulation data in São Paulo coast, Brazil and, for this purpose, a battery of biomarkers of defense mechanisms was analyzed and linked to contaminants' body burden in a weigh‐of‐evidence approach. The brown musselPerna pernawas selected to be transplanted from a farming area (Caraguatatuba) to four possibly polluted sites: Engenho D'Água, DTCS (Dutos e Terminais do Centro‐Oeste de São Paulo) oil terminal (Sao Sebastiao zone), Palmas Island, and Itaipu (It; Santos Bay zone). After 3 months of exposure in each season, mussels were recollected and the cytochrome P4501A (CYP1A)‐ and CYP3A‐like activities, glutathione‐S‐transferase and antioxidants enzymes (catalase, glutathione peroxidase, and glutathione reductase) were analyzed in gills. The concentrations of polycyclic aromatic hydrocarbons, linear alkylbenzenes, and nonessential metals (Cr, Cd, Pb, and Hg) in whole tissue were also analyzed and data were linked to biomarkers' responses by multivariate analysis (principal component analysis—factor analysis). A representation of estimated factor scores was performed to confirm the factor descriptions and to characterize the studied stations. Biomarkers exhibited most significant alterations all year long in mussels transplanted to It, located at Santos Bay zone, where bioaccumulation of organic and inorganic compounds was detected. This integrated approach using transplanted mussels showed satisfactory results, pointing out differences between sites, seasons, and critical areas, which could be related to land‐based contaminants' sources. The influence of natural factors and other contaminants (e.g., pharmaceuticals) on biomarkers' responses are also discussed. © 2010 Wiley Periodicals, Inc. Environ Toxicol, 2012.
The Boundaries of Context and Their Significance
Authors: Guichun GUO
Published: August 2010

In the study of contextualism, the most noticeable and at the same time ambiguous problem is how to ascertain the boundaries of context. This article tries to explore the boundaries of context and the significance of the “contextualizing movement” which began in the 1980s. The establishment of boundaries can be analyzed from three aspects: the syntactic boundary, the semantic boundary, and the pragmatic boundary. This differentiation offers meaningful perspectives for grasping the method of contextual analysis, strengthening its position and influence in scientific explanation.
Lack of effects of tomato products on endothelial function in human subjects: results of a randomised, placebo-controlled cross-over study
Authors: Stangl Verena , Kuhn Claudia , Hentschel Sonja , Jochmann Nicoline , Jacob Christine , Böhm Volker , Fröhlich Kati , Müller Lars , Gericke Christine , Lorenz Mario
Published: August 2010

Epidemiological studies suggest that consumption of tomato products reduces the risk of CVD via antioxidant, hypocholesterolaemic and anti-inflammatory mechanisms. Although experimental data also describe beneficial effects on endothelial function, clinical data in human subjects are lacking. To test the hypothesis that tomato ingestion ameliorates endothelial function, we randomised healthy non-smoking postmenopausal women to consume a buttered roll with and without tomato purée (70 g) in a cross-over design. Endothelial-dependent flow-mediated dilation (FMD) and endothelial-independent nitro-mediated dilation of the brachial artery were assessed with high-resolution ultrasound (13 MHz linear array transducer). Acute (24 h) and long-term (7 d) effects were examined after daily consumption of the described meal. Nineteen volunteers completed the protocol and provided technically suitable ultrasound measurement data. Plasma lycopene levels increased from 0·30 (sem0·04) (baseline) to 0·42 (sem0·04) and to 0·74 (sem0·06) μmafter 24 h and 7 d, respectively, with tomato purée consumption. These data indicated an effective absorption of the tomato product. However, both acute and long-term tomato purée consumption had no effects on endothelium-dependent or -independent dilation of the brachial artery. In addition, we found no correlation between lycopene plasma levels and FMD. In conclusion, consumption of tomato products associated with a significant increase in plasma lycopene levels had no effects on endothelial function in healthy postmenopausal women.
State of Independence: Explaining and Maintaining the Distinctive Competence of the British Journal of Political Science
Authors: Nagel Jack H.
Published: August 2010

Uniquely among leading generalist journals in political science, the BJPolS is independent of any professional association. Although organizational sponsorship confers great advantages, the BJPolS has thrived during its first forty years because able editors exploited their independence to adopt policies that were less feasible for official journals subject to membership pressures – a distinctive focus on contemporary theory, receptivity to overseas contributors, flexibility about longer articles and dual submissions, and active editorial discretion. These practices should continue to serve the journal well despite challenges posed by technological change. In responding to specialized competitors, the BJPolS should maintain its aspiration to publish papers that address ‘problems of general significance to students of politics’ by connecting analytical models to empirical evidence and enduring normative goals.
Discursive Meaning of Hope for Older Persons with Advanced Cancer and their Caregivers
Authors: Duggleby Wendy , Holtslander Lorraine , Steeves Megan , Duggleby-Wenzel Shanda , Cunningham Shannon
Published: August 2010

Cette étude a utilisé l’approche du discours critique de van Dijik afin d’explorer le discours sociétaux actuel sur l’espoir, et d’explorer l’espoir des patients agées avec cancer terminale, leurs soignants et leurs infirmières primaires. Quarante-trois articles de presse traitant de l’espoir et de cancer ont été recueillies et analysées pour explorer comment l’espoir est socialement construite par les médias de presse. Des entrevues individuelles de face à face, qualitatives et ouvertes ont été menées avec trois triades, constitués d’un patient de cancer palliatif âgé, un conjoint, et une infirmière primaire. Le discours prédominant de l’espoir et de cancer dans les articles de presse a été considérée comme discriminatoire à raison de l’âge; il a transmit le message que le seul espoir légitime qui existe pour les personnes atteintes d’un cancer est d’espérer un remède. Ce message a causé de la confusion et de la détresse pour les patients, leurs conjoints, et leur infirmières primaires, étant donné que leurs propre discours d’espoir ont été axés sur le confort, la paix et le maintien des relations à la fin de vie.
One More Probabilistic Reformulation of the Four Colour Conjecture
Authors: MATIYASEVICH Yu.
Published: August 2010

The paper presents yet another way to reformulate the Four Colour Conjecture as a statement concerning conditional probabilities of certain events involving planar graphs.
Pegging Graphs Yields a Small Diameter
Authors: GERKE STEFANIE , STEGER ANGELIKA , WORMALD NICHOLAS
Published: August 2010

We consider the following process for generating large random cubic graphs. Starting with a given graph, repeatedly add edges that join the midpoints of two randomly chosen edges. We show that the growing graph asymptotically almost surely has logarithmic diameter. This process is motivated by a particular type of peer-to-peer network. Our method extends to similar processes that generate regular graphs of higher degree.
An Operating Method with Lateral Scan for Reducing the Error in Topography Caused by the Tip-Sample Angle in Atomic Force Microscopy
Authors: Zhou Fa-Quan , Zhao Xue-Zeng , Wang Fei , Wang Yue-Yu
Published: August 2010

The atomic force microscopes (AFM) images are obtained by keeping the bending of the cantilever unchanged in contact mode. However, it is found that changes in the tip-sample angle during parallel scan result in error in the topographic image. It is also discovered that measurement results obtained in the blind scan region contained large errors. In contrast, regions opposite the blind scan region gave more reliable result. To eliminate this topographic error caused by change in the tip-sample angle, a new operating method with lateral scan is utilized in AFM. Comparative experiments have been performed, and the results show that the error could be eliminated or decreased by using the operating method.
‘Currency manipulation’ and world trade
Authors: STAIGER ROBERT W. , SYKES ALAN O.
Published: August 2010

Central bank intervention in foreign exchange markets may, under some conditions, stimulate exports and retard imports. In the past few years, this issue has moved to center stage because of the foreign exchange policies of China. Numerous public officials and commentators argue that China has engaged in impermissible ‘currency manipulation’, and various proposals for stiff action against China have been advanced. This paper considers the relationship between exchange rate policy and international trade, and addresses the questions of whether and how currency manipulation should be addressed by the international trading system. Our conclusions are at odds with much of what is currently being said by proponents of multilateral or unilateral actions against China. In particular, we question whether China's practices can be adjudicated to be ‘manipulation’ under international law, and doubt that their trade effects can be identified with the degree of confidence necessary to ascertain whether the practices ‘frustrate the intent’ of WTO/GATT commitments. The difficulty of identifying the trade effects of currency practices undermines the ability of the WTO dispute resolution system to address them, and calls into question the wisdom and legitimacy of unilateral countermeasures that have been proposed in various quarters.
Pioneers in Optics: Étienne-Jules Marey and Ignazio Porro
Authors: Davidson Michael W.
Published: August 2010

Étienne-Jules Marey was born in Beaune, France, on March 5, 1830, to a wine merchant and a teacher. To satisfy his father's wishes, he decided to study medicine, attending the Faculty of Medicine in Paris. Marey's fascination with both animals and mechanics inspired him to concentrate on physiology, and it was during his investigations of this field that he became involved in optics.

Ignazio Porro's primary contribution to optics was an innovative prism image erecting system that is commonly used in binoculars and stereomicroscopes, though he also invented and improved a number of other scientific instruments. Today Porro is often considered to have been ahead of his time in many ways. The Italian engineer received little acclaim or monetary compensation for his innovative devices, which only came to be fully appreciated and widely utilized after his death. In fact, when Ernst Abbe attempted to patent binoculars containing his own prism erecting system in 1893, the physicist was very surprised to find that someone else had invented and patented the design decades earlier. Despite his own intense work in the field of optics, Abbe had never heard of the inventor, a telling indication of Porro's difficulties.
Microscopy Today Innovation Awards
Authors: Lyman Charles
Published: August 2010

The Microscopy Today Innovation Awards were established to honor innovative microscopy-related products and methods that appeared in the previous year. Winning products and methods are selected on the basis of their importance and usefulness to the microscopy community. The innovations most likely to win are those that provide better, faster, or entirely new methods of analysis by some type of microscope or microanalytical instrument.
AFM Measurements of DNA Molecule Electron Transport Properties
Authors: McMahon Jim
Published: August 2010

Deoxyribonucleic acid (DNA) has been considered as a possibility for molecular electronics. Because DNA is able to recognize other molecules—other strands of DNA—and because it binds together with similar DNA strands in a very unique way, scientists have suggested the possibility of using DNA as an electronic circuit without having to build in any other circuitry. The DNA would bind with other similar DNA strands that it recognizes and then use the connecting properties of the DNA to create a self-assembled biological wire for electrical conduction. Until recently, uncertainty existed about whether DNA could conduct at all, and if it could, how well it could conduct. Scientific speculations ranged from DNA being a superconductor to a complete insulator. Recent research, however, by Dr. Sidney R. Cohen in collaboration with Dr. Ron Naaman and Dr. Claude Nogues of the Weizmann Institute of Science, Scanned Probe Microscopy Unit, in Rehovot, Israel, aided by the enabling technologies of ultra-high-resolution microscopy and negative-stiffness vibration isolation, has shed new light on the electrical transport properties of DNA, focusing on the capacity of single molecules of DNA to transport current along individual strands.
Security Stripes: Visible Seals for Robust Documentation and Authentication of Digital Images
Authors: Bradley Charles , Mancuso James
Published: August 2010

Digital images carry a great deal of information, but they should not stand alone. They need to be accompanied by experimental variables, equipment used, personnel involved, image-processing operations performed, and site information. It is essential to maintain a link between pixel data and experimental conditions associated with the picture.
X-Ray Microanalysis of Art Glass Surfaces
Authors: Simmons R.B.
Published: August 2010

In recent years there has been a virtual explosion in the world of art glass. New glass formulations have brought a host of new colors into the marketplace, and the availability of low-cost, high-quality torches and other tools has brought art glass to the hobbyist. In addition to burn risks and possible cutting injury, there are a number of less obvious hazards that should be known to novice glass workers. One of these is the presence of heavy metals in or on glass surfaces and possibly in the atmosphere immediately surrounding the work area, presenting both potential skin contact and inhalation hazards. This study examines the metallic surfaces generated on five glass colors commonly used in art glass jewelry.
Model‐based estimate of the heat budget in the East China Sea
Authors: Liu Na , Eden Carsten , Dietze Heiner , Wu Dexing , Lin Xiaopei
Published: August 2010

Using a global ocean model with regionally focused high resolution (1/10°) in the East China Sea (ECS), we studied the oceanic heat budget in the ECS. The modeled sea surface height variability and eddy kinetic energy are consistent with those derived from satellite altimetry. Significant levels of eddy kinetic energy are found east of the Ryukyu Islands and east of Taiwan, where the short‐term variability is spawned by active mesoscale eddies coalescing with the circulation. Furthermore, the simulated vertical cross‐stream structure of the Kuroshio (along the Pollution Nagasaki line) and the volume transport through each channel in the ECS are in good agreement with the observational estimates. The time‐averaged temperature fluxes across the Taiwan Strait (TWS), Tsushima Strait (TSS), and the 200 m isobath between Taiwan and Japan are 0.20 PW, 0.21 PW, and 0.05 PW, respectively. The residual heat flux of 0.04 PW into the ECS is balanced by the surface heat loss. The eddy temperature flux across the 200 m isobath is 0.005 PW, which accounts for 11.2% of the total temperature flux. The Kuroshio onshore temperature flux has two major sources: the Kuroshio intrusion northeast of Taiwan and southwest of Kyushu. The Ekman temperature flux induced by the wind stress in the ECS shows the same seasonal cycle and amplitude as the onshore temperature flux, with a maximum in autumn and a minimum in summer. We conclude that the Ekman temperature flux dominates the seasonal cycle of Kuroshio onshore flux.
Measurements and characterization of particle size distributions in coastal waters
Authors: Reynolds R. A. , Stramski D. , Wright V. M. , Woźniak S. B.
Published: August 2010

The particle size distribution (PSD) plays a central role in understanding many facets of the aquatic ecosystem, yet it is rarely measured in field studies and no single method provides a complete description of the PSD. In this study, size distributions of diverse particle suspensions were measured using a laser diffractometer (LISST‐100X), an electrical impedance particle sizer (Coulter Counter), and a particle imaging system (FlowCAM). All three instruments provided similar estimates of average particle size for suspensions of known standards. For broad polydisperse assemblages of particles a generally good agreement was found between the LISST and Coulter over a large portion of the size spectrum (from ∼1–3 μm to 50 μm), with the exception of suspensions exhibiting narrow features which were not accurately resolved with the LISST measurement. For featureless PSDs, however, the LISST provides an adequate proxy and has the capability for in situ measurements with high spatial and temporal resolution. We examined LISST field measurements from coastal regions within the context of a commonly used parameterization of the PSD. Analysis of nearly 5500 size distributions suggest that the average slope of the power law distribution for particles larger than 3 μm is −3.5. However, in many coastal waters this model provides a poor description of the PSD owing to the presence of significant peaks in the distribution. The combination of these data with Mie scattering calculations suggest that such departures from the idealized PSD can significantly impact the prediction of seawater optical properties.
Improved predictability of stratospheric sudden warming events in an atmospheric general circulation model with enhanced stratospheric resolution
Authors: Marshall Andrew G. , Scaife Adam A.
Published: August 2010

The impact of stratospheric resolution on the predictability of stratospheric sudden warming (SSW) events and their effect on European climate is cleanly assessed in two versions of the Hadley Center's atmospheric climate model, Hadley Center global environmental model. The standard 38‐level version of the model extends to an altitude of 39 km (∼3 mbar) while the extended 60‐level version has enhanced stratospheric resolution and reaches 84 km altitude (∼0.004 mbar). We show that the L60 model captures SSW events earlier than the L38 model (12 days before an event compared with 8 days) and influences the simulation of European surface winter cold spells at seasonal time scales, highlighting the benefit of high vertical resolution and daily initialization for seasonal forecasting. This is likely due to earlier initialization of the downward‐propagating SSW signal in the higher‐top L60 model. We suggest however that the increased lead time for predicting SSW events is unlikely to be improved much further by raising the model lid above the L60 model domain.
Detecting low‐frequency earthquakes within non‐volcanic tremor in southern Taiwan triggered by the 2005 Mw8.6 Nias earthquake
Authors: Tang Chi‐Chia , Peng Zhigang , Chao Kevin , Chen Chau‐Huei , Lin Cheng‐Horng
Published: August 2010

We use a matched filter technique to detect 41 low‐frequency earthquakes (LFEs) within 700‐s of triggered tremor signals in the Southern Central Range in Taiwan during the surface waves of the 2005 Mw8.6 Nias earthquake off the coast of northern Sumatra. The depth distributions of LFEs after double‐difference relocations concentrate at the depth range of 12–38 km below the background seismicity and above the Moho depth inferred from receiver function studies. The locations of LFEs are close to the downward extension of the steep‐dipping Chaochou‐Lishan fault with only modestly high Vp/Vs ratios (1.75–1.85). Our observation indicates that at least portions of triggered tremor consists of many LFEs, similar to ambient tremor observed at other major plate boundary faults.
Role of IMF Bx in the solar wind‐magnetosphere‐ionosphere coupling
Authors: Peng Z. , Wang C. , Hu Y. Q.
Published: August 2010

As far as the role of the interplanetary magnetic field (IMF) in the solar wind‐magnetosphere‐ionosphere (SMI) coupling is concerned, the role of the IMF Bx has more or less been ignored. Recent studies have shown that the IMF Bx plays an important role in the geometry of the bow shock under low Alfvén Mach numbers. Using global MHD simulations, this paper presents a further examination of the effects of the IMF Bx on the geometry of the magnetopause, the ionospheric transpolar potential, and the magnetopause reconnection rate, which quantify the SMI coupling process, under low Alfvén Mach numbers. The role of the IMF Bx manifests itself in three aspects: (1) the magnetopause shifts toward either north or south, depending on whether the Bx · Bz is negative or positive, whereas the bow shock expands in the opposite direction; (2) during southward IMF, the magnetic merging line shifts northward (southward) on the day side and southward (northward) on the night side for Bx > 0 (Bx < 0); (3) both the ionospheric transpolar potential and the magnetopause reconnection rate decrease with increasing Bx, and the relative reduction may reach as high as 20% under extreme cases. The physical mechanism for this reduction is attributed to the change in the width of the magnetosheath, which is sensitive to the variation of Bx under low Alfvén Mach numbers.
Managing Diverse Stakeholders in Enterprise Systems Projects: A Control Portfolio Approach
Authors: Soh Christina , Chua Cecil Eng Huang , Singh Harminder
Published: August 2010

While substantial research has examined the control of Information systems (IS) projects, most studies In this area have only examined how one controller manages a single group of controllees. However, many IS projects, especially enterprise systems projects (often initiated by an organization's corporate headquarters, and involving business unit users and consultants), have multiple stakeholders. The corporate headquarters (the project's principal controller) must simultaneously ensure that the various stakeholders are aligned with the project's goals despite their diverse motivations, and that the stakeholders collaborate with each other to achieve project success. Behavior control theory argues that the controller enacts a control portfolio of formal and Informal controls. However, the presence of multiple controllee groups increases the complexity of vertical controller- controllee relationships, the salience of controllee-controllee relationships, and the interaction between these vertical and horizontal relationships. We therefore examined the creation and evolution of the control portfolio In a multi-stakeholder project over a period of 14 months. We found that (1) the principal controller did enact separate controls for the user and consultant groups; (2) there was more than one controller - the principal controller co-existed with subordinate controllers; and (3) controls enacted by the subordinate controllers and other controllees that cut across stakeholder groups required the support of the principal controller.
Barcodes, Rfids, Lemonade and Conversation
Authors: Gogan Janis L , Rao Ashok
Published: August 2010

Atul Mahajan nicknamed ‘AM,’ a wealthy Indian, sits on the board of Kisan Group, his family's chemical company (family and company names disguised). Charged with managing the Mahajan family wealth, he has formed a private equity group that helps build mid-market companies. He has also launched a few technology-enabled ventures of his own, including a company that failed in its attempts to sell a service that used encrypted and masked barcodes for document authentication and a successful company that provided administrative and data management support for pharmaceutical clinical trials. Now, apparently with sufficient resources to contemplate another entrepreneurial venture, AM wonders whether to revive the document authentication business, with a turnkey solution or one or more services that would use encrypted RFID tags instead of the older barcode technology. This teaching case was developed based on interviews with Mr. ‘Mahajan’ and two other employees. The case provides an opportunity for students to Investigate technical, strategic and operational uncertainties and challenges associated with building a business around a new technology. For business schools that are attempting to ‘globalize’ their curriculum, the case offers the benefit of presenting the point of view of a well-connected Indian entrepreneur.
Revisiting the vibrational spectra of silicon hydrides on Si(100)-(2×1) surface: What is on the surface when disilane dissociates?
Authors: Ong S. W. , Tok E. S. , Kang H. Chuan
Published: August 2010

Even though the decomposition of disilane on silicon surfaces has been extensively studied, the molecular mechanism for its decomposition has not been fully resolved. The general view motivated partly by spectroscopic data is that decomposition occurs through silicon-silicon bond dissociation although there is evidence from kinetics that silicon-hydrogen bond dissociation is important, and perhaps even dominant. Thus, we reexamine the assignment of the experimental vibrational peaks observed in disilane and silane adsorption in order to assess the evidence for the silicon hydride species that are formed during decomposition. We calculate the vibrational density of states for a number of silicon hydride species on the Si(100)-(2×1) surface using Car–Parrinello molecular dynamics. We obtain the calculated vibrational frequency in the adiabatic limit by extrapolating to zero orbital mass, calibrating our method using the well-established monohydride peak. The calculated vibrational frequencies of the monohydride are in good agreement experimental data. Our results show that the spectroscopic data for silicon hydrides does not preclude the occurrence of Si2H5 on the surface thus providing evidence for silicon-hydrogen bond dissociation during disilane adsorption. Specifically, we find that an experimentally observed vibrational peak at 2150 cm−1 that has generally been attributed to the trihydride SiH3 is more likely to be due to Si2H5. Our results also clear up the assignment of two peaks for monohydride species adsorbed at the edge of a growing terrace, and a peak for the dihydride species adsorbed in the interdimer configuration.
Spectroscopic characterization of Be2+X Σ2u+ and the ionization energy of Be2
Authors: Antonov Ivan O. , Barker Beau J. , Bondybey Vladimir E. , Heaven Michael C.
Published: August 2010

Rotationally resolved spectra for Be2+ have been recorded using the pulsed-field ionization zero kinetic energy photoelectron technique. Vibrational levels in the range v+=0–6 were observed. The rotational selection rules confirmed that the ground state is Σ2u+, resulting from the removal of an electron from the σu antibonding orbital of Be2. The bond energy and equilibrium distance for Be2+ were found to be De+=16 438(5) cm−1 and Re+=2.211(8) Å. The ionization energy for Be2 [59 824(2) cm−1] was also refined by these measurements. Comparisons with high-level theoretical results indicate that the bonding in Be2+ is adequately described by multi reference singles and doubles configuration interaction (MRDCI) calculations that employ moderate to large scale basis sets.
Stages in the interaction of deuterium atoms with amorphous hydrogenated carbon films: Isotope exchange, soft-layer formation, and steady-state erosion
Authors: Oehrlein G. S. , Schwarz-Selinger T. , Schmid K. , Schlüter M. , Jacob W.
Published: August 2010

We report studies of the interactions of quantified deuterium (hydrogen) atom beams with hard amorphous hydrogenated carbon films at a substrate temperature of ∼330 K in an ultrahigh-vacuum chamber. The modification/erosion of a-C:H (a-C:D) films was monitored in situ by ellipsometry in real time. By interpreting the ellipsometric information and combining it with measurements of the absolute D areal density changes in the a-C:H (a-C:D) films by ion beam analysis as a function of D (H) atom fluence, we are able to distinguish three sequential stages of D interaction with hard a-C:H films. The first stage is replacement of bonded hydrogen by deuterium up to an areal density of ∼5×1015 D cm−2 to a depth of ∼1.4 nm from the surface. This phase is complete after a deuterium fluence of ≈2×1018 cm−2. The effective cross section for isotopic exchange of H with D atoms for the a-C:H layer is found to be σ=2.0×10−18 cm2, and is close to the cross section for H abstraction from a carbon surface. This may indicate that H abstraction by D from the a-C:H surface is the rate limiting step for isotope exchange in this situation. Hydrogen replacement is followed by creation of additional C–D bonds in the near-surface region and increases the D areal density by about 2.5×1015 D cm−2. By ellipsometry this process can be observed as the formation of a soft a-C:D layer on top of the hard a-C:H bulk film, with the soft layer extending about 1.4 nm from the surface. This stage is complete after a deuterium fluence of about 2×1019 cm−2. Subsequently, steady-state erosion of the a-C:H film takes place. Here, a soft a-C:D layer with roughly constant thickness (∼1.4 nm) remains on the hard a-C:H substrate and is dynamically reformed as the underlying hard a-C:H film becomes thinner. A similar sequence of processes takes place at a substrate temperature of 650 K, albeit at a much faster rate.
Enhancement of silicon solar cell efficiency by upconversion: Optical and electrical characterization
Authors: Fischer S. , Goldschmidt J. C. , Löper P. , Bauer G. H. , Brüggemann R. , Krämer K. , Biner D. , Hermle M. , Glunz S. W.
Published: August 2010

Upconversion (UC) of subband-gap photons is a promising possibility to enhance solar cell efficiency by making also the subband-gap photons useful. For this application, we investigate the material system of trivalent erbium doped sodium yttrium fluoride (NaYF4:20%Er3+), which shows efficient UC suitable for silicon solar cells. We determine the optical UC efficiency by calibrated photoluminescence measurements. Because these data are free from any influence of losses associated with the application of the upconverter to the solar cell, the obtained values constitute the upper limit that can be achieved with an optimized device. Subsequently, we compare the results of the optical measurements with the results obtained by using solar cells as detectors on which the upconverter material is applied. We find an optical UC quantum efficiency of 5.1% at a monochromatic irradiance of 1880 W m−2 (0.27 cm2 W−1) at 1523 nm. The device of silicon solar cell and applied upconverter showed an external quantum efficiency of 0.34% at an irradiance of 1090 W m−2 (0.03 cm2 W−1) at 1522 nm. The differences are explained by the optical losses occurring in the upconverter solar cell device, which are dominated by the transmission of the solar cell and the incomplete absorption of the upconverting layer, and the nonlinear behavior of the upconverter.
Vortex nucleation in spin-torque nanocontact oscillators
Authors: Devolder T. , Kim Joo-Von , Manfrini M. , van Roy W. , Lagae L. , Chappert C.
Published: August 2010

We present an experimental study of the nucleation rate associated with current-driven vortex oscillations in magnetic nanocontacts. We find that the nucleation and subsequent steady-state oscillation of a vortex can be initiated using current pulses as short as a few nanoseconds, yielding instant on oscillator capability. The nucleation rate is governed by an Arrhenius law, with an exponential dependence on the applied current magnitude. The mechanism for the vortex nucleation is discussed and compared to analytical estimates assuming the transient presence of a vortex-antivortex pair.
A critical factor affecting on the performance of blue-violet InGaN multiquantum well laser diodes: Nonradiative centers
Authors: Shin D. M. , Park J. , Nguyen D. H. , Jang Y. D. , Yee K. J. , Lee D. , Choi Y. H. , Jung S. K. , Noh M. S.
Published: August 2010

Carrier lifetime at room temperature (RT) was measured for blue-violet emitting InGaN multiquantum wells as a function of excitation intensity. The carrier lifetime of a p/n-doped waveguide sample (PNLD) was longer than those of undoped or n-doped waveguide samples. For PNLD, the long decay component became dominant at moderate excitation, in contrast to the others for which the fast decaying component remained dominant. The lifetime behavior of PNLD, in conjunction with its strong photoluminescence intensity, originates from the reduction of nonradiative centers. We conclude that the defect density is an important determinant of the RT performance of blue-violet laser diodes.
Exchange coupled composite bit patterned media
Authors: Krone P. , Makarov D. , Schrefl T. , Albrecht M.
Published: August 2010

A micromagnetic study on the magnetization reversal in bit patterned media (BPM) with each bit consisting of an exchange coupled composite (ECC) layer stack is presented. The simulations reveal superior magnetic properties of the combined ECC/BPM scheme, in particular for graded media, using uncorrelated distributions of magnetic anisotropy values in order to lower the switching field while keeping a high thermal stability of the media. In this study, a route for narrowing the switching field distribution of the bit array is provided as well, which is vital for the applicability of the BPM concept in magnetic data storage.
Thermal annealing-induced vertical phase separation of copper phthalocyanine: Fullerene bulk heterojunction in organic photovoltaic cells
Authors: Wei H. X. , Li J. , Xu Z. Q. , Cai Y. , Tang J. X. , Li Y. Q.
Published: August 2010

The effect of thermal annealing treatment on the morphology change in bulk heterojunction (BHJ) in organic photovoltaic cells was studied by photoemission spectroscopy. The results reveal that vertical phase separation upon annealing occurs in typical BHJ layer formed between planar molecule CuPc and spherical C60 with inhomogeneous concentration distribution in profile, varying from CuPc-rich near the air surface to C60-rich adjacent to the substrate interface. The morphology variation is associated with the difference in surface energy of CuPc and C60, leading to the accumulation of CuPc to the interface with air to lower the overall energy of the free surface.
Extraction-controlled quantum cascade lasers
Authors: Wacker Andreas
Published: August 2010

A simple two-well design for terahertz quantum cascade lasers is proposed which is based on scattering injection and the efficient extraction of electrons from the lower laser level by resonant tunneling. In contrast to existing designs this extraction also controls the positive differential conductivity. The device is analyzed by calculations based on nonequilibrium Green’s functions, which predict lasing operation well above 200 K at a frequency of 2.8 THz.
AMPA receptors are exocytosed in stimulated spines and adjacent dendrites in a Ras-ERK–dependent manner during long-term potentiation
Authors: Patterson Michael A. , Szatmari Erzsebet M. , Yasuda Ryohei
Published: August 2010

The exocytosis of AMPA receptors is a key step in long-term potentiation (LTP), yet the timing and location of exocytosis and the signaling pathways involved in exocytosis during synaptic plasticity are not fully understood. Here we combine two-photon uncaging with two-photon imaging of a fluorescent label of surface AMPA receptors to monitor individual AMPA receptor exocytosis events near spines undergoing LTP. AMPA receptors that reached the stimulated spine came from a combination of preexisting surface receptors (70–90%) and newly exocytosed receptors (10–30%). We observed exocytosis in both the dendrite and spine under basal conditions. The rate of AMPA receptor exocytosis increased ∼5-fold during LTP induction and decayed to the basal level within ∼1 min, both in the stimulated spine and in the dendrite within ∼3 μm of the stimulated spine. AMPA receptors inserted in the spine were trapped in the spine in an activity-dependent manner. The activity-dependent exocytosis required the Ras-ERK pathway, but not CaMKII. Thus, diffusive Ras-ERK signaling presumably serves as an important means for signaling from synapses to dendritic shafts to recruit AMPA receptors into synapses during LTP.
Evolutionary origin of a functional gonadotropin in the pituitary of the most primitive vertebrate, hagfish
Authors: Uchida Katsuhisa , Moriyama Shunsuke , Chiba Hiroaki , Shimotani Toyokazu , Honda Kaori , Miki Makoto , Takahashi Akiyoshi , Sower Stacia A. , Nozaki Masumi
Published: August 2010

Hagfish, which lack both jaws and vertebrae, are considered the most primitive vertebrate known, living or extinct. Hagfish have long been the enigma of vertebrate evolution not only because of their evolutionary position, but also because of our lack of knowledge on fundamental processes. Key elements of the reproductive endocrine system in hagfish have yet to be elucidated. Here, the presence and identity of a functional glycoprotein hormone (GPH) have been elucidated from the brown hagfishParamyxine atami. The hagfish GPH consists of two subunits, α and β, which are synthesized and colocalized in the same cells of the adenohypophysis. The cellular and transcriptional activities of hagfish GPHα and -β were significantly correlated with the developmental stages of the gonad. The purified native GPH induced the release of gonadal sex steroids in vitro. From our phylogenetic analysis, we propose that ancestral glycoprotein α-subunit 2 (GPA2) and β-subunit 5 (GPB5) gave rise to GPHα and GPHβ of the vertebrate glycoprotein hormone family, respectively. The identified hagfish GPHα and -β subunits appear to be the typical gnathostome GPHα and -β subunits based on the sequence and phylogenetic analyses. We hypothesize that the identity of a single functional GPH of the hagfish, hagfish GTH, provides critical evidence for the existence of a pituitary-gonadal system in the earliest divergent vertebrate that likely evolved from an ancestral, prevertebrate exclusively neuroendocrine mechanism by gradual emergence of a previously undescribed control level, the pituitary, which is not found in the Protochordates.