bluuebunny/crossref_metadata_2025 huggingface dataset:
A novel fast fractal image coding algorithm based on texture feature
Authors: Wang Wei , Ren Fuji , Suzuki Motoyuki
Published: July 2012

A novel, fast fractal image coding algorithm based on the texture feature is proposed in this paper. Fractal image coding is a very promising technique for image compression. However, it has not been widely used because of the long encoding time and high computational complexity. The most fractal image encoding time is spent in determining the approximate D‐block from a large D‐blocks library by using the global searching method. Clustering the D‐blocks library is an effective method to reduce the encoding time. First, all the D‐blocks are clustered into several parts based on the new texture feature α derived from variation function; second, for each R‐block, the approximate D‐blocks are searched for in the same part. In the search process, we import control parameter δ; this step avoids losing the most approximate D‐block for each R‐block. Finally, the R‐blocks whose least errors are larger than the threshold given in advance are coded by the quad tree method. We have performed a simulation with MATLABR2010a to verify the effectiveness of the proposed algorithm. The experimental results show that the proposed algorithm can be over 6 times faster than the moment‐feature‐based fractal image algorithm; in addition, the proposed algorithm also improves the quality of the decoded image and increases the PSNR's average value by 2 dB. The comparisons demonstrate that this method is better than the fractal image coding algorithm based on statistical features. © 2012 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.
Male breast cancer: treatment options
Authors: Gui Gerald
Published: July 2012

As male breast cancer is so rare, treatment recommendations are in general based upon data derived from clinical trials of women with breast cancer. In the second article in this series, the author looks at the available treatment options for breast cancer in men. Copyright © 2012 John Wiley & Sons
Solar reflectance, surface adhesion, and thermal conductivity of wood/natural rubber composite sheet with Tio2/polyurethane topcoat for roofing applications
Authors: Hamaviriyapornwattana Natita , Sombatsompop Narongrit , Markpin Teerasak , Kositchaiyong Apisit , Wimolmala Ekachai
Published: July 2012

Effects of titanium dioxide (TiO2) dosage in polyurethane (PU) coating and PU coating thickness on solar reflectance, surface adhesion, crack resistance to bending, and thermal conductivity of wood/(natural rubber) (WNR) composite sheet were studied before and after prolonged UV aging. The TiO2powder content added to the PU coating was varied from 0 to 15 parts per hundred parts of PU. The average PU coating thickness on the WNR composite sheet was altered from 127 ± 10 to 315 ± 10 μm. The experimental results suggested that the solar reflectance slightly increased with increasing TiO2powder but did not change upon varying the PU coating thicknesses. The presence of TiO2in the PU coating caused a slight decrease in thermal conductivity because of porosities occurring due to the presence of voids, but increasing the TiO2powder content in the coating resulted in a progressive increase in thermal conductivity of the composite sheet. In a UV‐accelerated weathering tester (UVB 313 nm), the lightness of the PU coating slightly increased owing to PU discoloration, whereas the solar reflectance, PU/WNR layer adhesion, and crack resistance to bending remained unaffected with increasing UV aging time. J. VINYL ADDIT. TECHNOL., 18:184–191, 2012. © 2012 Society of Plastics Engineers
Crystal Structure, Magnetic and Transport Properties of CeRu1–xNixAl (x = 0.5)
Authors: Janka Oliver , Baumbach Ryan E. , Ronning Filip , Thompson Joe D. , Bauer Eric D. , Kauzlarich Susan M.
Published: July 2012

Single crystals of CeRu0.5Ni0.5Al can be obtained from a Ce‐Ni melt using elements as starting materials. The presented compound crystallizes in the orthorhombic space group Pnma (no. 62) with a = 700.38(7), b = 416.92(4) and c = 1562.84(16) pm in the LaNiAl structure type. The compound shows an unusual temperature dependence of the magnetic susceptibility for T < 20 K although the cerium cations exhibit no local moment behavior. This feature is also visible in the electrical resistivity.
Influence of different mineral nitrogen sources (NO−3-N vs. NH+4-N) on arbuscular mycorrhiza development and N transfer in a Glomus intraradices–cowpea symbiosis
Authors: Ngwene Benard , Gabriel Elke , George Eckhard
Published: July 2012

Labeled nitrogen (15 N) was applied to a soil-based substrate in order to study the uptake of N by Glomus intraradices extraradical mycelium (ERM) from different mineral N (NO
3
−
vs. NH
4
+
) sources and the subsequent transfer to cowpea plants. Fungal compartments (FCs) were placed within the plant growth substrate to simulate soil patches containing root-inaccessible, but mycorrhiza-accessible, N. The fungus was able to take up both N-forms, NO
3
−
and NH
4
+
. However, the amount of N transferred from the FC to the plant was higher when NO
3
−
was applied to the FC. In contrast, analysis of ERM harvested from the FC showed a higher 15 N enrichment when the FC was supplied with 15NH
4
+
compared with 15NO
3
−
. The 15 N shoot/root ratio of plants supplied with 15NO
3
−
was much higher than that of plants supplied with 15NH
4
+
, indicative of a faster transfer of 15NO
3
−
from the root to the shoot and a higher accumulation of 15NH
4
+
in the root and/or intraradical mycelium. It is concluded that hyphae of the arbuscular mycorrhizal fungus may absorb NH
4
+
preferentially over NO
3
−
but that export of N from the hyphae to the root and shoot may be greater following NO
3
−
uptake. The need for NH
4
+
to be assimilated into organically bound N prior to transport into the plant is discussed.
Simulation Modeling of Policies Directed at Youth Sugar‐Sweetened Beverage Consumption
Authors: Levy David T. , Friend Karen B.
Published: July 2012

Childhood obesity is a significant public health problem requiring innovative solutions. While recent reviews indicate that some policies show promise, there is a lack of information regarding which policies, and policy combinations, work best. Low‐nutrition, energy‐dense foods and beverages such as sugar‐sweetened beverages (SSBs) have been identified as a major contributor to the problem. The purpose of this paper is to use simulation modeling to show how changes in three categories of SSB policies—school nutrition, school‐based education, and taxes—impact SSB and other food consumption. The model shows that policies directed at SSBs, particularly tax hikes, could lead to substantial reductions in the number of calories consumed by youth. The estimates, however, are subject to a high degree of uncertainty. Estimates from school‐based nutrition and school‐based education policies, while also helping to reduce caloric intake, generally show smaller effects than tax policies and considerable variation around parameter estimates for individual and combined policies. We conclude with a discussion of the limits of the model, and suggest where additional information is needed. Limitations notwithstanding, simulation modeling is a promising methodology that can help advance our understanding of policy effects, thereby helping policymakers to better formulate effective policies to reduce obesity prevalence and the associated social harms.
Disorders of phospholipids, sphingolipids and fatty acids biosynthesis: toward a new category of inherited metabolic diseases
Authors: Lamari F. , Mochel F. , Sedel F. , Saudubray J. M.
Published: July 2012

We wish to delineate a novel, and rapidly expanding, group of inborn errors of metabolism with neurological/muscular presentations: the defects in phospholipids, sphingolipids and long chain fatty acids biosynthesis. At least 14 disorders have been described so far. Clinical presentations are diverse but can be divided into (1) diseases of the central nervous system; (2) peripheral neuropathies; and (3) muscular/cardiac presentations. (1) Leukodystrophy and/or iron deposits in basal ganglia is a common feature of phospholipase A2 deficiency, fatty acid hydroxylase deficiency, and pantothenate kinase‐associated neurodegeneration. Infantile epilepsy has been reported in GM3 synthetase deficiency. Spastic quadriplegia with ichthyosis and intellectual disability are the presenting signs of the elongase 4 deficiency and the Sjogren‐Larsson syndrome caused by fatty aldehyde dehydrogenase deficiency. Spastic paraplegia and muscle wasting are also seen in patients with mutations in the neuropathy target esterase gene. (2) Peripheral neuropathy is a prominent feature in PHARC syndrome due to α/β‐hydrolase 12 deficiency, and in hereditary sensory autonomic neuropathy type I due to serine palmitoyl‐CoA transferase deficiency. (3) Muscular/cardiac presentations include recurrent myoglobinuria in phosphatidate phosphatase 1 (Lipin1) deficiency; cardiomyopathy and multivisceral involvement in Barth syndrome secondary to tafazzin mutations; congenital muscular dystrophy due to choline kinase deficiency, Sengers syndrome due to acylglycerol kinase deficiency and Chanarin Dorfman syndrome due to α/β‐ hydrolase 5 deficiency. These synthesis defects of complex lipid molecules stand at the frontier between classical inborn errors of metabolism and other genetic diseases involving the metabolism of structural proteins.
Dietary arginine supplementation enhances immune responses to inactivatedPasteurella multocidavaccination in mice
Authors: Ren Wenkai , Zou Lingxiu , Li Nengzhang , Wang Yan , Liu Gang , Peng Yuanyi , Ding Jiannan , Cai Lichuang , Yin Yulong , Wu Guoyao
Published: July 2012

The present study was conducted to determine the adjuvant effect of arginine in mice immunised with inactivated vaccine. Mice immunised with an inactivatedPasteurella multocidavaccine and fed diets supplemented with 0·2 % (vaccine-0·2 %) or 0·5 % (vaccine-0·5 %) arginine exhibited 100 % protection from a challenge withP. multocidaserotype A (CQ2) at a dose of 4·4 × 105colony-forming units (2LD50; median lethal dose), when compared with mice receiving no arginine supplementation. Meanwhile, antibody titres in the vaccine-0·2 % arginine group were much higher than those in the vaccine-oil adjuvant group before challenge and at 36 h post-infection. Furthermore, immunisation with the inactivated vaccine and dietary supplementation with 0·2 % arginine increased serum levels of glutathione peroxidase, in comparison with immunisation with the inactivated vaccine and an oil adjuvant. Collectively, dietary arginine supplementation confers an immunostimulatory effect in mice immunised with the inactivatedP. multocidavaccine. The present results also indicate that optimal supplemental doses of arginine are 0·2–0·5 % in the mouse model.
Supplementation of xanthophylls increased antioxidant capacity and decreased lipid peroxidation in hens and chicks
Authors: Gao Yu-Yun , Xie Qing-Mei , Ma Jing-Yun , Zhang Xiang-Bin , Zhu Ji-Mei , Shu Ding-Ming , Sun Bao-Li , Jin Ling , Bi Ying-Zuo
Published: July 2012

The present study investigated the effects of xanthophyll supplementation on production performance, antioxidant capacity (measured by glutathione peroxidase, superoxide dismutase (SOD), catalase, total antioxidant capacity (T-AOC), and reduced glutathione:oxidised glutathione ratio (GSH:GSSG)) and lipid peroxidation (measured by malondialdehyde (MDA)) in breeding hens and chicks. In Expt 1, 432 hens were fed diets supplemented with 0 (control group), 20 or 40 mg xanthophyll/kg diet. Blood samples were taken at 7, 14, 21, 28 and 35 d of the trial. Liver and jejunal mucosa were sampled at 35 d. Both xanthophyll groups improved serum SOD at 21 and 28 d, serum T-AOC at 21 d and liver T-AOC, and serum GSH:GSSG at 21, 28 and 35 d and liver GSH:GSSG. Xanthophylls also decreased serum MDA at 21 d in hens. Expt 2 was a 2 × 2 factorial design. Male chicks hatched from 0 or 40 mgin ovoxanthophyll/kg diet of hens were fed a diet containing either 0 or 40 mg xanthophyll/kg diet. Liver samples were collected at 0, 7, 14 and 21 d after hatching. Blood samples were also collected at 21 d.In ovo-deposited xanthophylls increased antioxidant capacity and decreased MDA in the liver mainly within 1 week after hatching. Maternal effects gradually vanished during 1–2 weeks after hatching. Dietary xanthophylls increased antioxidant capacity and decreased MDA in the liver and serum mainly from 2 weeks onwards. Data suggested that xanthophyll supplementation enhanced antioxidant capacity and reduced lipid peroxidation in different tissues of hens and chicks.
We Have to Be Discrete About This: A Non-Parametric Imputation Technique for Missing Categorical Data
Authors: Cranmer Skyler J. , Gill Jeff
Published: July 2012

Missing values are a frequent problem in empirical political science research. Surprisingly, the match between the measurement of the missing values and the correcting algorithms applied is seldom studied. While multiple imputation is a vast improvement over the deletion of cases with missing values, it is often unsuitable for imputing highly non-granular discrete data. We develop a simple technique for imputing missing values in such situations, which is a variant of hot deck imputation, drawing from the conditional distribution of the variable with missing values to preserve the discrete measure of the variable. This method is tested against existing techniques using Monte Carlo analysis and then applied to real data on democratization and modernization theory. Software for our imputation technique is provided in a free, easy-to-use package for the R statistical environment.
From Sonic Art to Visual Music: Divergences, convergences, intersections
Authors: Garro Diego
Published: July 2012

This paper introduces strategies for the electroacoustic community to relate to, and engage with, the visual music phenomenon. It addresses technological, historical, cultural and idiomatic intersections between the two art forms. From the personal viewpoint of a trained synaesthete of acousmatic origin, the boundaries between sonic and audiovisual compositional practices appear somewhat porous. The electroacoustic language is intrinsically visual, even within its acousmatic paradigm. Visible morphologies acquire a sonorous dimension as soon as we uproot them from their cinematographic habitat and plunge them into the cauldron of a new alchemy. Multi-disciplinary lines of enquiry are essential to elucidate the workings of complex multimediatic interactions such as those at play in visual music. Yet, a holistic view of the creative and technological pathways is equally significant so that artistic truths, and myths, can be (re)discovered amidst lines of code or loops of wire connecting our computer peripherals. Thus this article is written both with the language of an analyst and, perhaps more, with the expressions and idiosyncrasies of an academic composer. A few selected examples from the contemporary repertoire are discussed to exemplify a variety of approaches to visual music composition, including extracts from the work Patah (Garro 2010).
From prediction to experimental validation: desmoglein 2 is a functionally relevant substrate of matriptase in epithelial cells and their reciprocal relationship is important for cell adhesion
Authors: Wadhawan Vinita , Kolhe Yogesh A. , Sangith Nikhil , Gautam Amit Kumar Singh , Venkatraman Prasanna
Published: July 2012

Accurate identification of substrates of a protease is critical in defining its physiological functions. We previously predicted that Dsg-2 (desmoglein-2), a desmosomal protein, is a candidate substrate of the transmembrane serine protease matriptase. The present study is an experimental validation of this prediction. As demanded by our published method PNSAS [Prediction of Natural Substrates from Artificial Substrate of Proteases; Venkatraman, Balakrishnan, Rao, Hooda and Pol (2009) PLoS ONE 4, e5700], this enzyme–substrate pair shares a common subcellular distribution and the predicted cleavage site is accessible to the protease. Matriptase knock-down cells showed enhanced immunoreactive Dsg-2 at the cell surface and formed larger cell clusters. When matriptase was mobilized from intracellular storage deposits to the cell surface there was a decrease in the band intensity of Dsg-2 in the plasma membrane fractions with a concomitant accumulation of a cleaved product in the conditioned medium. The exogenous addition of pure active recombinant matriptase decreased the surface levels of immunoreactive Dsg-2, whereas the levels of CD44 and E-cadherin were unaltered. Dsg-2 with a mutation at the predicted cleavage site is resistant to cleavage by matriptase. Thus Dsg-2 seems to be a functionally relevant physiological substrate of matriptase. Since breakdown of cell–cell contact is the first major event in invasion, this reciprocal relationship is likely to have a profound role in cancers of epithelial origin. Our algorithm has the potential to become an integral tool for discovering new protease–substrate pairs.
A novel PKB/Akt inhibitor, MK-2206, effectively inhibits insulin-stimulated glucose metabolism and protein synthesis in isolated rat skeletal muscle
Authors: Lai Yu-Chiang , Liu Yang , Jacobs Roxane , Rider Mark H.
Published: July 2012

PKB (protein kinase B), also known as Akt, is a key component of insulin signalling. Defects in PKB activation lead to insulin resistance and metabolic disorders, whereas PKB overactivation has been linked to tumour growth. Small-molecule PKB inhibitors have thus been developed for cancer treatment, but also represent useful tools to probe the roles of PKB in insulin action. In the present study, we examined the acute effects of two allosteric PKB inhibitors, MK-2206 and Akti 1/2 (Akti) on PKB signalling in incubated rat soleus muscles. We also assessed the effects of the compounds on insulin-stimulated glucose uptake, glycogen and protein synthesis. MK-2206 dose-dependently inhibited insulin-stimulated PKB phosphorylation, PKBβ activity and phosphorylation of PKB downstream targets (including glycogen synthase kinase-3α/β, proline-rich Akt substrate of 40 kDa and Akt substrate of 160 kDa). Insulin-stimulated glucose uptake, glycogen synthesis and glycogen synthase activity were also decreased by MK-2206 in a dose-dependent manner. Incubation with high doses of MK-2206 (10 μM) inhibited insulin-induced p70 ribosomal protein S6 kinase and 4E-BP1 (eukaryotic initiation factor 4E-binding protein-1) phosphorylation associated with increased eEF2 (eukaryotic elongation factor 2) phosphorylation. In contrast, Akti only modestly inhibited insulin-induced PKB and mTOR (mammalian target of rapamycin) signalling, with little or no effect on glucose uptake and protein synthesis. MK-2206, rather than Akti, would thus be the tool of choice for studying the role of PKB in insulin action in skeletal muscle. The results point to a key role for PKB in mediating insulin-stimulated glucose uptake, glycogen synthesis and protein synthesis in skeletal muscle.
Structural switching of Cu,Zn-superoxide dismutases at loop VI: insights from the crystal structure of 2-mercaptoethanol-modified enzyme
Authors: Ihara Kentaro , Fujiwara Noriko , Yamaguchi Yoshiki , Torigoe Hidetaka , Wakatsuki Soichi , Taniguchi Naoyuki , Suzuki Keiichiro
Published: July 2012

Cu,Zn SOD1 (superoxide dismutase 1) is implicated in FALS (familial amyotrophic lateral sclerosis) through the accumulation of misfolded proteins that are toxic to neuronal cells. Loop VI (residues 102–115) of the protein is at the dimer interface and could play a critical role in stability. The free cysteine residue, Cys111 in the loop, is readily oxidized and alkylated. We have found that modification of this Cys111 with 2-ME (2-mercaptoethanol; 2-ME-SOD1) stabilizes the protein and the mechanism may provide insights into destabilization and the formation of aggregated proteins. Here, we determined the crystal structure of 2-ME-SOD1 and find that the 2-ME moieties in both subunits interact asymmetrically at the dimer interface and that there is an asymmetric configuration of segment Gly108 to Cys111 in loop VI. One loop VI of the dimer forms a 310-helix (Gly108 to His110) within a unique β-bridge stabilized by a hydrogen bond between Ser105-NH and His110-CO, while the other forms a β-turn without the H-bond. The H-bond (H-type) and H-bond free (F-type) configurations are also seen in some wild-type and mutant human SOD1s in the Protein Data Bank suggesting that they are interconvertible and an intrinsic property of SOD1s. The two structures serve as a basis for classification of these proteins and hopefully a guide to their stability and role in pathophysiology.
Photoactivated structural dynamics of fluorescent proteins
Authors: Bourgeois Dominique , Regis-Faro Aline , Adam Virgile
Published: July 2012

Proteins of the GFP (green fluorescent protein) family have revolutionized life sciences because they allow the tagging of biological samples in a non-invasive genetically encoded way. ‘Phototransformable’ fluorescent proteins, in particular, have recently attracted widespread interest, as their fluorescence state can be finely tuned by actinic light, a property central to the development of super-resolution microscopy. Beyond microscopy applications, phototransformable fluorescent proteins are also exquisite tools to investigate fundamental protein dynamics. Using light to trigger processes such as photoactivation, photoconversion, photoswitching, blinking and photobleaching allows the exploration of the conformational landscape in multiple directions. In the present paper, we review how structural dynamics of phototransformable fluorescent proteins can be monitored by combining X-ray crystallography, in crystallo optical spectroscopy and simulation tools such as quantum chemistry/molecular mechanics hybrid approaches. Besides their usefulness to rationally engineer better performing fluorescent proteins for nanoscopy and other biotechnological applications, these investigations provide fundamental insights into protein dynamics.
The emergence of protein complexes: quaternary structure, dynamics and allostery
Authors: Perica Tina , Marsh Joseph A. , Sousa Filipa L. , Natan Eviatar , Colwell Lucy J. , Ahnert Sebastian E. , Teichmann Sarah A.
Published: July 2012

All proteins require physical interactions with other proteins in order to perform their functions. Most of them oligomerize into homomers, and a vast majority of these homomers interact with other proteins, at least part of the time, forming transient or obligate heteromers. In the present paper, we review the structural, biophysical and evolutionary aspects of these protein interactions. We discuss how protein function and stability benefit from oligomerization, as well as evolutionary pathways by which oligomers emerge, mostly from the perspective of homomers. Finally, we emphasize the specificities of heteromeric complexes and their structure and evolution. We also discuss two analytical approaches increasingly being used to study protein structures as well as their interactions. First, we review the use of the biological networks and graph theory for analysis of protein interactions and structure. Secondly, we discuss recent advances in techniques for detecting correlated mutations, with the emphasis on their role in identifying pathways of allosteric communication.
Aggregation in dilute aqueous tert-butyl alcohol solutions: Insights from large-scale simulations
Authors: Gupta Rini , Patey G. N.
Published: July 2012

Molecular dynamics simulations employing up to 64 000 particles are used to investigate aggregation and microheterogeneity in aqueous tert-butyl alcohol (TBA) solutions for TBA mole fractions Xt ⩽ 0.1. Four different force fields are considered. It is shown that the results obtained can be strongly dependent on the particular force field employed, and can be significantly influenced by system size. Two of the force fields considered show TBA aggregation in the concentration range Xt ≈ 0.03 − 0.06. For these models, systems of 64 000 particles are minimally sufficient to accommodate the TBA aggregates. The structures resulting from TBA aggregation do not have a well-defined size and shape, as one might find in micellar systems, but are better described as TBA-rich and water-rich regions. All pair correlation functions exhibit long-range oscillatory behavior with wavelengths that are much larger than molecular length scales. The oscillations are not strongly damped and the correlations can easily exceed the size of the simulation cell, even for the low TBA concentrations considered here. We note that these long-range correlations pose a serious problem if one wishes to obtain certain physical properties such as Kirkwood-Buff integrals from simulation results. In contrast, two other force fields that we consider show little sign of aggregation for Xt ≲ 0.08. In our 64 000 particle simulations all four models considered show demixing-like behavior for Xt ≳ 0.1, although such behavior is not evident in smaller systems of 2000 particles. The meaning of the demixing-like behavior is unclear. Since real TBA-water solutions do not demix, it might be an indication that all four models we consider poorly represent the real system. Alternatively, it might be an artifact of finite system size. Possibly, the apparent demixing indicates that for Xt ≳ 0.1, the stable TBA aggregates are simply too large to fit into the simulation cell. Our results provide a view of the possible nature of microheterogeneity in dilute TBA-water solutions, and of the associated long correlation lengths. It is clear that system size can be a very important factor in simulations of these solutions, and must be taken into account in the evaluation and development of TBA-water force fields.
Determination of neutral beam energy fractions from collisional radiative measurements on DIII-D
Authors: Thomas D. M. , Grierson B. A. , Muñoz Burgos J. M. , Van Zeeland M. A.
Published: July 2012

Neutral beams based on positive ion source technology are a key component of contemporary fusion research. An accurate assessment of the injected beam species mix is important for determining the actual plasma heating and momentum input as well as proper interpretation of beam-based diagnostics. On DIII-D, the main ion charge-exchange spectroscopy system is used to extract well-resolved intensity ratios of the Doppler-shifted Dα emission from the full, half, and third energy beam components for a variety of beam operational parameters. In conjunction with accurate collisional-radiative modeling, these measurements indicate the assumed species mix and power fractions can vary significantly and should be regularly monitored and updated for the most accurate interpretation of plasma performance. In addition, if stable active control of the power fractions can be achieved through appropriate source tuning, the resulting control over the deposition profile can serve as an additional experimental knob for advanced tokamak studies, e.g., varying the off axis beam current drive without altering the beam trajectory.
Scanning tunneling microscopy/spectroscopy studies of resistive switching in Nb-doped SrTiO3
Authors: Chen Y. L. , Wang J. , Xiong C. M. , Dou R. F. , Yang J. Y. , Nie J. C.
Published: July 2012

Scanning tunneling microscopy and spectroscopy (STM/S) was utilized to study the resistive switching (RS) effect in Nb-doped SrTiO3 (STON). It was found that the RS effect could be realized on the STON surface by applying an appropriate bias on the STM tip, and the RS block could be controlled at nanometer scale. The electrode contact effect on the RS process could be excluded according to the STM method. More importantly, the investigation of scanning tunneling spectroscopy combined with the measurement of x-ray photoelectron spectroscopy demonstrated that the oxygen migration should be the dominant mechanism for the variation of electronic structure during the RS process, which can explain the origin of RS in this oxide. These results can be helpful for both the understanding of RS and its applications.
Effects of image charges, interfacial charge discreteness, and surface roughness on the zeta potential of spherical electric double layers
Authors: Gan Zecheng , Xing Xiangjun , Xu Zhenli
Published: July 2012

We investigate the effects of image charges, interfacial charge discreteness, and surface roughness on spherical electric double layer structures in electrolyte solutions with divalent counterions in the setting of the primitive model. By using Monte Carlo simulations and the image charge method, the zeta potential profile and the integrated charge distribution function are computed for varying surface charge strengths and salt concentrations. Systematic comparisons were carried out between three distinct models for interfacial charges: (1) SURF1 with uniform surface charges, (2) SURF2 with discrete point charges on the interface, and (3) SURF3 with discrete interfacial charges and finite excluded volume. By comparing the integrated charge distribution function and the zeta potential profile, we argue that the potential at the distance of one ion diameter from the macroion surface is a suitable location to define the zeta potential. In SURF2 model, we find that image charge effects strongly enhance charge inversion for monovalent interfacial charges, and strongly suppress charge inversion for multivalent interfacial charges. For SURF3, the image charge effect becomes much smaller. Finally, with image charges in action, we find that excluded volumes (in SURF3) suppress charge inversion for monovalent interfacial charges and enhance charge inversion for multivalent interfacial charges. Overall, our results demonstrate that all these aspects, i.e., image charges, interfacial charge discreteness, their excluding volumes, have significant impacts on zeta potentials of electric double layers.
Theoretical study of charge recombination at the TiO2-electrolyte interface in dye sensitised solar cells
Authors: Maggio E. , Martsinovich N. , Troisi A.
Published: July 2012

The charge recombination reaction from the semiconductor (TiO2) conduction band to electron accepting electrolytes (I2, I2−, I3−) in dye-sensitised solar cells is investigated theoretically. The non-adiabatic theory of electron transfer has been adapted to compute the charge transfer rate measured in different experimental settings (namely with and without external illumination). In both cases we are able to provide an atomic level description of the charge recombination to the electrolyte (CRE), which is in good agreement with the experimental data available. The model employs a detailed density-functional theory (DFT) description of the semiconductor-electrolyte interface and the internal reorganization energy. A continuum dielectric model is used to evaluate the external component of the reorganization energy due to the solvent degrees of freedom. The intrinsic limitations of DFT are kept to a minimum by taking two key energetic parameters (the conduction band edge and the reaction energy) from the experiments. The proposed methodology correctly reproduces (i) the ratio between CRE rate to iodine and triiodide in dark, (ii) the absolute CRE rate to triiodide in dark, and (iii) the absolute CRE rate to I2− under illumination.
Defect assisted thermal synthesis of crystalline aluminum borate nanowires
Authors: Gonzalez-Martinez I. , Bachmatiuk A. , Gorantla S. , Kunstmann J. , Bezugly V. , Gemming T. , Büchner B. , Cuniberti G. , Rümmeli M. H.
Published: July 2012

Aluminum borate is attractive in that the material has excellent mechanical properties, chemical inertness, high temperature stability, and a low coefficient of thermal expansion. Moreover, aluminum borate has advantages over a more traditional material, SiC, in that it does not readily oxidize at high temperature and can be produced at lower cost. In this study, we demonstarte a facile route to grow single crystal aluminum borate nanowires directly on bare sapphire surfaces without the need for a catalyst. Our findings point to a growth mechanism in which lattice defects allow B or B2O2 diffusion. The nanowire formation occurs as a means to relieve residual stress that arises due to thermal expansion mismatch between the aluminum borate and alumina phases. Indeed, at a more local scale, this same stress process facilitates diffussion. By adding iron oxide, which has a high diffusion rate in sapphire, one can accelerate this process. The growth mechanism is fundamentally different to the more usual fabrication routes which employ vapor-solid-liquid or vapor-solid growth processes.
CdS nanocrystal-sensitized solar cells with polyaniline as counter electrode
Authors: AbdulAlmohsin S. , Armstrong J. , Cui J. B.
Published: July 2012

CdS nanocrystal-sensitized solar cells (NCSSCs) were investigated by using polyaniline (PANI) as a replacement for conventional platinum counter electrode. The growth time of the NCs significantly affects the solar cell performance. At an optimum growth, the NCSSCs exhibit 0.83% of the conversion efficiency in comparison to 0.13% for the identical cells without CdS NCs. Electrochemical impedance spectroscopy showed that the charge transfer in the solar cells with CdS nanocrystals was improved. The enhanced overall energy conversion efficiency by NCs is attributed to improved light absorption and suppressed recombination rate of interfacial charges with injection, resulting in significantly improved charge transfer and electron life time. In addition, the PANI electrodes with large surface area and ideal corrosion-inertness toward polysulfide redox exhibit promising application potential as a counter electrode for NCSSCs. This study demonstrates that the solution grown CdS nanocrystals and polyaniline are potentially useful for fabricating high performance NCSSCs, which is technically attractive for large scale and economic production.
Numerical studies of third-harmonic generation in laser filament in air perturbed by plasma spot
Authors: Feng Liu-Bin , Lu Xin , Xi Ting-Ting , Liu Xiao-Long , Li Yu-Tong , Chen Li-Ming , Ma Jing-Long , Dong Quan-Li , Wang Wei-Min , Sheng Zheng-Ming , He Duanwei , Zhang Jie
Published: July 2012

Third-harmonic emission from laser filament intercepted by plasma spot is studied by numerical simulations. Significant enhancement of the third-harmonic generation is obtained due to the disturbance of the additional plasma. The contribution of the pure plasma effect and the possible plasma-enhanced third-order susceptibility on the third-harmonic generation enhancement are compared. It is shown that the plasma induced cancellation of destructive interference [Y. Liu et al., Opt. Commun. 284, 4706 (2011)] of two-colored filament is the dominant mechanism of the enhancement of third-harmonic generation.
Photoluminescence and Raman studies on Ge-based complexes in Si-doped GaInP epilayers grown on Germanium
Authors: He W. , Lu S. L. , Jiang D. S. , Dong J. R. , Tackeuchi A. , Yang H.
Published: July 2012

Photoluminescence and Raman scattering measurements were performed on Si-doped GaInP grown on Ge. The deep broadband photoluminescence (PL) emission centered around 1.4 eV exhibits a strong dependence of strength on Si dopants, which is suggested to be due to [Ge(Ga,In)-V(Ga,In)] complexes. A strong evidence to support the existence of [Ge(Ga,In)-Si(Ga,In)] complexes in Si-doped GaInP is shown by Raman spectra. The blue shift of broad PL emission and the increased recombination life time with increased temperatures were explained by the competition between [Ge(Ga,In)-V(Ga,In)] and [Ge(Ga,In)-Si(Ga,In)] complexes.
Plasmonic mediated nucleation of resonant nano-cavities
Authors: Karpov V. G. , Nardone M. , Subashiev A. V.
Published: July 2012

We show that the energy required for nucleation can be efficiently supplied by the electromagnetic field in resonance with plasmonic oscillations of a nucleus, and the field frequency dictates its strongly anisotropic resonant shape. The predicted effect is especially strong for nucleation of pancake shaped nano-cavities in skin depth metallic layers. This significant modification of nucleation physics can have important implications in nano-photonics and optical recording.
GaAsP solar cells on GaP substrates by molecular beam epitaxy
Authors: Tomasulo S. , Nay Yaung K. , Simon J. , Lee M. L.
Published: July 2012

We demonstrate molecular beam epitaxy (MBE) of GaAsxP1−x/GaP solar cells over a range of bandgap energies (Eg). Identical GaAs0.66P0.34 cells on GaAs and GaP exhibit similar properties; GaAs0.66P0.34/GaP cells with Eg = 1.82 eV produced an open-circuit voltage (Voc) of 1.24 V, ∼40 mV lower than previous GaAs0.66P0.34/GaAs cells. We then grew GaAs0.56P0.44/GaP cells with Eg = 1.92 eV to investigate their suitability for wide-Eg applications, reaching Voc = 1.27 V. For potential dual-junction integration on Si, we grew Eg = 1.71 eV GaAs0.73P0.27/GaP cells, attaining Voc = 1.15 V. These results indicate that GaAsxP1−x/GaP solar cells by MBE are promising for integration onto Si and for other photovoltaic applications.
Beam profile indicator for swift heavy ions using phosphor afterglow
Authors: Zhan T. Z. , Xu C. N. , Yamada H. , Terasawa Y. , Zhang L. , Iwase H. , Kawai M.
Published: July 2012

In this letter, we report a beam profile indicator for swift heavy ions (SHIs) which utilizes the afterglow of phosphors. Clear marks are left on SrAl2O4:Eu2+ and CaSrAl2Si2O8:Eu2+ samples by SHI irradiation through a permanent change of their afterglow intensity. The afterglow intensity of the SHI-irradiated areas has a Gaussian distribution. Moreover, afterglow intensity and irradiation fluence are linearly related, indicating that this type of indicator has good dose linearity. The results suggest that long-lasting phosphors are promising SHI beam profile indicators with high spatial resolution.
Awareness of the Light Field: The Case of Deformation
Authors: van Doorn Andrea J. , Koenderink Jan J. , Todd James T. , Wagemans Johan
Published: July 2012

Human observers group local shading patterns into global super-patterns that appear to be illuminated in some unitary fashion. Many years ago, this was noticed for the case of uniform, unidirectional illumination. Recently, we found that it also applies to convergent and divergent illumination flows, but that human observers are blind to rotational light flow patterns (in the sense of being unable to group the local shading patterns). We now report that human observers are also blind to deformation patterns. This is perhaps interesting because convergent, divergent, rotational, and deformation patterns all occur in natural light fields. This is an idiosyncrasy of the human visual system, on par with the fact that visual awareness fails to present the observer with saddle shapes.
Overview of the physics and engineering design of NSTX upgrade
Authors: Menard J.E. , Gerhardt S. , Bell M. , Bialek J. , Brooks A. , Canik J. , Chrzanowski J. , Denault M. , Dudek L. , Gates D.A. , Gorelenkov N. , Guttenfelder W. , Hatcher R. , Hosea J. , Kaita R. , Kaye S. , Kessel C. , Kolemen E. , Kugel H. , Maingi R. , Mardenfeld M. , Mueller D. , Nelson B. , Neumeyer C. , Ono M. , Perry E. , Ramakrishnan R. , Raman R. , Ren Y. , Sabbagh S. , Smith M. , Soukhanovskii V. , Stevenson T. , Strykowsky R. , Stutman D. , Taylor G. , Titus P. , Tresemer K. , Tritz K. , Viola M. , Williams M. , Woolley R. , Yuh H. , Zhang H. , Zhai Y. , Zolfaghari A.
Published: July 2012

The spherical tokamak (ST) is a leading candidate for a Fusion Nuclear Science Facility (FNSF) due to its compact size and modular configuration. The National Spherical Torus eXperiment (NSTX) is a MA-class ST facility in the US actively developing the physics basis for an ST-based FNSF. In plasma transport research, ST experiments exhibit a strong (nearly inverse) scaling of normalized confinement with collisionality, and if this trend holds at low collisionality, high fusion neutron fluences could be achievable in very compact ST devices. A major motivation for the NSTX Upgrade (NSTX-U) is to span the next factor of 3–6 reduction in collisionality. To achieve this collisionality reduction with equilibrated profiles, NSTX-U will double the toroidal field, plasma current, and NBI heating power and increase the pulse length from 1–1.5 s to 5–8 s. In the area of stability and advanced scenarios, plasmas with higher aspect ratio and elongation, high β
N, and broad current profiles approaching those of an ST-based FNSF have been produced in NSTX using active control of the plasma β and advanced resistive wall mode control. High non-inductive current fractions of 70% have been sustained for many current diffusion times, and the more tangential injection of the 2nd NBI of the Upgrade is projected to increase the NBI current drive by up to a factor of 2 and support 100% non-inductive operation. More tangential NBI injection is also projected to provide non-solenoidal current ramp-up as needed for an ST-based FNSF. In boundary physics, NSTX measures an inverse relationship between the scrape-off layer heat-flux width and plasma current that could unfavourably impact next-step devices. Recently, NSTX has successfully demonstrated substantial heat-flux reduction using a snowflake divertor configuration, and this type of divertor is incorporated in the NSTX-U design. The physics and engineering design supporting NSTX Upgrade is described.
Cocycles and continuity
Authors: Becker Howard
Published: July 2012

The topic of this paper is the Mackey Cocycle Theorem: every Borel almost cocycle is equivalent to a Borel strict cocycle. This is a theorem about locally compact groups which is not true for arbitrary Polish groups. We discuss the theorem, the open question of whether the theorem generalizes to some nonlocally compact Polish groups, the generalization to non-Borel cocycles, and other subjects associated with the theorem. Traditionally, the subject of cocycles and related matters has been considered in the context of standard Borel

G
G

-spaces. It is now known that a standard Borel

G
G

-space has a topological realization as a Polish

G
G

-space. This makes it possible to consider the subject from a topological point of view. The main theorem of this paper is that the conclusion of the Mackey Cocycle Theorem is equivalent to continuity properties of the almost cocycle. Even in the locally compact case, this continuity is a new result.
Septin 7 forms a complex with CD2AP and nephrin and regulates glucose transporter trafficking
Authors: Wasik Anita A. , Polianskyte-Prause Zydrune , Dong Meng-Qiu , Shaw Andrey S. , Yates John R. , Farquhar Marilyn G. , Lehtonen Sanna
Published: July 2012

Podocytes are insulin-sensitive and take up glucose in response to insulin. This requires nephrin, which interacts with vesicle-associated membrane protein 2 (VAMP2) on GLUT4 storage vesicles (GSVs) and facilitates their fusion with the plasma membrane. In this paper, we show that the filament-forming GTPase septin 7 is expressed in podocytes and associates with CD2-associated protein (CD2AP) and nephrin, both essential for glomerular ultrafiltration. In addition, septin 7 coimmunoprecipitates with VAMP2. Subcellular fractionation of cultured podocytes revealed that septin 7 is found in both cytoplasmic and membrane fractions, and immunofluorescence microscopy showed that septin 7 is expressed in a filamentous pattern and is also found on vesicles and the plasma membrane. The filamentous localization of septin 7 depends on CD2AP and intact actin organization. A 2-deoxy-d-glucose uptake assay indicates that depletion of septin 7 by small interfering RNA or alteration of septin assembly by forchlorfenuron facilitates glucose uptake into cells and further, knockdown of septin 7 increased the interaction of VAMP2 with nephrin and syntaxin 4. The data indicate that septin 7 hinders GSV trafficking and further, the interaction of septin 7 with nephrin in glomeruli suggests that septin 7 may participate in the regulation of glucose transport in podocytes.
Ndm, a coiled-coil domain protein that suppresses macropinocytosis and has effects on cell migration
Authors: Kelsey Jessica S. , Fastman Nathan M. , Noratel Elizabeth F. , Blumberg Daphne D.
Published: July 2012

The ampA gene has a role in cell migration in Dictyostelium discoideum. Cells overexpressing AmpA show an increase in cell migration, forming large plaques on bacterial lawns. A second-site suppressor of this ampA-overexpressing phenotype identified a previously uncharacterized gene, ndm, which is described here. The Ndm protein is predicted to contain a coiled-coil BAR-like domain—a domain involved in endocytosis and membrane bending. ndm-knockout and Ndm-monomeric red fluorescent protein–expressing cell lines were used to establish a role for ndm in suppressing endocytosis. An increase in the rate of endocytosis and in the number of endosomes was detected in ndm−cells. During migration ndm−cells formed numerous endocytic cups instead of the broad lamellipodia structure characteristic of moving cells. A second lamellipodia-based function—cell spreading—was also defective in the ndm−cells. The increase in endocytosis and the defect in lamellipodia formation were associated with reduced chemotaxis in ndm−cells. Immunofluorescence results and glutathione S-transferase pull-down assays revealed an association of Ndm with coronin and F-actin. The results establish ndm as a gene important in regulating the balance between formation of endocytic cups and lamellipodia structures.
The yeast Hsp70 Ssa1 is a sensor for activation of the heat shock response by thiol-reactive compounds
Authors: Wang Yanyu , Gibney Patrick A. , West James D. , Morano Kevin A.
Published: July 2012

The heat shock transcription factor HSF1 governs the response to heat shock, oxidative stresses, and xenobiotics through unknown mechanisms. We demonstrate that diverse thiol-reactive molecules potently activate budding yeast Hsf1. Hsf1 activation by thiol-reactive compounds is not consistent with the stresses of misfolding of cytoplasmic proteins or cytotoxicity. Instead, we demonstrate that the Hsp70 chaperone Ssa1, which represses Hsf1 in the absence of stress, is hypersensitive to modification by a thiol-reactive probe. Strikingly, mutation of two conserved cysteine residues to serine in Ssa1 rendered cells insensitive to Hsf1 activation and subsequently induced thermotolerance by thiol-reactive compounds, but not by heat shock. Conversely, substitution with the sulfinic acid mimic aspartic acid resulted in constitutive Hsf1 activation. Cysteine 303, located within the nucleotide-binding domain, was found to be modified in vivo by a model organic electrophile, demonstrating that Ssa1 is a direct target for thiol-reactive molecules through adduct formation. These findings demonstrate that Hsp70 is a proximal sensor for Hsf1-mediated cytoprotection and can discriminate between two distinct environmental stressors.
Medical ethics
Authors: Hope Tony
Published: July 2012

Medicine is a moral enterprise as well as a scientific one. It is as important to give reasons for the ethical aspects as it is for the scientific aspects of a decision. The corollary of evidence-based medicine is reason-based ethics.

Two concepts central to many ethical aspects of clinical practice are autonomy and best interests....
Viral infections
Authors: Farrar Jeremy , Wills Bridgit , De Jong Menno , Warrell David A
Published: July 2012

Case History—A 29 yr old man presenting with headache, depressed mood and apathy.

Enteroviruses are responsible for 80 to 90% and mumps for 10 to 20% of diagnosed cases of viral meningitis, with many other viruses sometimes incriminated with considerable geographical and seasonal variation....