bluuebunny/crossref_metadata_2025_split huggingface dataset:
The nature of chemical bonds of the CaMn4O5 cluster in oxygen evolving complex of photosystem II: Jahn‐Teller distortion and its suppression by Ca doping in cubane structures
Authors: Yamaguchi K. , Yamanaka S. , Isobe H. , Saito T. , Kanda K. , Umena Y. , Kawakami K. , Shen J.‐R. , Kamiya N. , Okumura M. , Nakamura H. , Shoji M. , Yoshioka Y. 
Published: July 2012

AbstractFull geometry optimizations of mixed‐valence (MV) cubane Mn(III)4‐ωMn(IV)ωO4 cluster (ω = 0–4) by UB3LYP have been performed to elucidate Jahn‐Teller (JT) effects for the Mn(III) ions. The optimized geometries have elucidated acute triangle for Mn(III)2 Mn(X) (X = III,IV) core in the cubane, indicating the JT effect. The JT effect is not remakable for Mn(IV)2Mn(III) cores, showing obtuse triangle and it diminishes in Mn(IV)3 core with equilateral triangle. The replacement of one of Mn ions with Ca (or Sr) ion in the cubane structure has also been examined to elucidate multiple roles of Ca(II) ion. The Ca‐doping suppresses the JT effect even for Mn(III)2Mn(X) (X = III,IV) core because acute CaMnMn triangles with longer Ca‐Mn distances than the Mn‐Mn distance are newly formed. The suppression of the JT effect for Mn(IV)2 Mn(III) by Ca doping is also found because of the same reason. The Ca‐doped cubane in the CaMn4O5 cluster (1) of oxygen evolving complex (OEC) of photosystem II (PSII) exhibits two acute CaMnMn triangles and one almost equilateral CaMnMn triangle because of the elongation of the Mn1(d)‐Mn3(b) distance with the coordination of the extra Mn4(a) ion to the cubane. The Mn1(d)Mn2(c)Mn3(b) triangle becomes obtuse because of the suppression of the JT effect, indicating the Mn1(d)(III)Mn2(c)(IV)Mn3(b)(IV) valence state in the S1 state of 1. The JT distortion for Mn(III) ions modified by the Ca(or Sr) doping is coupled with the labile structural deformation for intracluster electron transfers via double exchange mechanism in 1. The structural anomalies of 1 revealed by the new XRD experiment are also crucial for derivation of several guiding principles for theoretical modeling of water splitting reaction at OEC of PSII. The hybrid DFT computational results for 1 have also supported these guiding principles that provide possible orbital and spin correlation diagrams for water splitting reactions. The Huckel‐Hubbard‐Hund (HHH) model has been used for qualitative understanding of these diagrams. Implications of the present computational results are discussed in relation to electronic and spin states of redox active Ca‐doped Mott insulators constructed with magnetic transition metals such as Mn, Fe, Co, Ni, etc. Strongly correlated electron systems (SCES) modified by doping of Ca, Sr, Zn, etc. have been elucidated as possible candidates of bio‐inspired artificial catalysts for water oxidation. © 2012 Wiley Periodicals, Inc.
Coloring random graphs online without creating monochromatic subgraphs
Authors: Mütze Torsten , Rast Thomas , Spöhel Reto 
Published: July 2012

AbstractConsider the following random process: The vertices of a binomial random graph Gn,p are revealed one by one, and at each step only the edges induced by the already revealed vertices are visible. Our goal is to assign to each vertex one from a fixed number r of available colors immediately and irrevocably without creating a monochromatic copy of some fixed graph F in the process. Our first main result is that for any F and r, the threshold function for this problem is given by p0(F,r,n) = n‐1/m*1(F,r), where m*1(F,r) denotes the so‐called online vertex‐Ramsey density of F and r. This parameter is defined via a purely deterministic two‐player game, in which the random process is replaced by an adversary that is subject to certain restrictions inherited from the random setting. Our second main result states that for any F and r, the online vertex‐Ramsey density m*1(F,r) is a computable rational number.Our lower bound proof is algorithmic, i.e., we obtain polynomial‐time online algorithms that succeed in coloring Gn,p as desired with probability 1 ‐ o(1) for any p(n) = o(n‐1/m*1(F,r)). © 2012 Wiley Periodicals, Inc. Random Struct. Alg. 44, 419–464, 2014
Subtle biobehavioral effects produced by paternal cocaine exposure
Authors: Killinger Catherine E. , Robinson Stacey , Stanwood Gregg D. 
Published: July 2012

AbstractDespite the increased prevalence of cocaine use and abuse in males when compared with females, possible effects of paternal cocaine exposure on biobehavioral development have received little attention. We therefore exposed male mice to cocaine (20 mg/kg, i.p.) or vehicle for 10 weeks and then used those mice as sires. We then behaviorally phenotyped the F1 offspring to assess the consequences of paternal cocaine exposure on brain function. We report the presence of a subtle but significant increase in immobility in the tail suspension test, a measure of behavioral depression, following paternal cocaine. Body weight was also significantly decreased in paternal cocaine‐exposed offspring. Other aspects of neurobehavioral function, including locomotor activity, anxiety, and learning and memory, were not affected by paternal cocaine history. These data suggest alterations in brain systems and/or circuitry underlying mood regulation in the offspring of cocaine‐using fathers. Synapse 2012. © 2012 Wiley Periodicals, Inc.
Study on the dielectric properties of biological cells using the electrokinetic method
Authors: Lin Cheng , Lisheng Zhong , Yue Zhang , Qinxue Yu , Yizhou Shi 
Published: July 2012

AbstractDifferent from hard particles with an ordinary surface structure, a biological cell is a soft particle which can be described as a hard particle covered with an ion‐penetrable surface layer of polyelectrolytes. In this paper, according to the electrokinetic theory of suspension of soft particles, the colloid vibration current (CVI) model of suspended biological cells is investigated. A CVI measurement system is set up in which ultrasonic pulses of different intensities are calibrated and used. The experimental results on electrolyte solutions and cell suspensions show that CVI is closely related to the ion and cell concentration of the sample solution. Along with the increased concentration of ions or cells, the CVI signal increased initially and then decreased for electrolyte solutions, but it was the reverse for a chicken blood cell suspension but stayed almost constant for a spawn suspension. All these phenomena were caused by the interactive electrokinetic polarization of ions and cells under the action of ultrasonic pulses. Through the analysis of the electrokinetic course of the cell suspension, it was found that the amplitude and slope of the electrokinetic curve could be used to characterize the dielectric properties of cells. The electrokinetic model and CVI measurement system are rather feasible, as shown by the experimental results. The electrokinetic measurement method shows a new nondestructive way for studying the charging properties of biological cells, and the method has an inherent advantage for the real‐time study of the biological effects of ultrasound on cells. © 2012 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.
A novel fast fractal image coding algorithm based on texture feature
Authors: Wang Wei , Ren Fuji , Suzuki Motoyuki 
Published: July 2012

AbstractA 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.
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

AbstractEffects 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

AbstractSingle 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

Abstract
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

AbstractChildhood 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

AbstractWe 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.
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.