bluuebunny/crossref_metadata_2025 huggingface dataset:
BKCa and hEag1 Channels Regulate Cell Proliferation and Differentiation in Human Bone Marrow‐Derived Mesenchymal Stem Cells
Authors: Zhang Ying‐Ying , Yue Jianbo , Che Hui , Sun Hai‐Ying , Tse Hung‐Fat , Li Gui‐Rong
Published: July 2013

Human bone marrow‐derived mesenchymal stem cells (MSCs) serve as a reservoir for the continuous renewal of various mesenchymal tissues; however, cellular physiology of ion channels is not fully understood. The present study investigated potential roles of large‐conductance Ca2+‐activated potassium (BKCa) channels and ether‐à‐go‐go potassium (hEag1 or Kv10.1) channels in regulating cell proliferation and differentiation in human MSCs. We found that inhibition of BKCa with paxilline or hEag1 with astemizole, or knockdown of BKCa with shRNAs targeting KCa1.1 or hEag1 channels with shRNAs targeting KCNH1 arrested the cells at G0/G1 phase. In addition, silencing BKCa or hEag1 channels significantly reduced adipogenic differentiation with decrease of lipid accumulation and expression of the adipocyte marker PPARγ, and decreased osteogenic differentiation with reduction of mineral precipitation and osteocalcin. These effects were accompanied with a reduced cyclin D1, cyclin E, p‐ERK1/2, and p‐Akt. Our results demonstrate that BKCa and hEag1 channels not only regulate cell proliferation, but also participate in the adipogenic and osteogenic differentiations in human MSCs, which indicates that BKCa and hEag1 channels may be essential in maintaining bone marrow physiological function and bone regeneration. J. Cell. Physiol. 229: 202–212, 2014. © 2013 Wiley Periodicals, Inc.
Comparison of TWINS and THEMIS observations of proton pitch angle distributions in the ring current during the 29 May 2010 geomagnetic storm
Authors: Grimes E. W. , Perez J. D. , Goldstein J. , McComas D. J. , Valek P. , Turner D.
Published: July 2013

The first comparison between energy‐dependent ion pitch angle distributions in the ring current deconvolved from Two Wide‐angle Imagining Neutral‐atom Spectrometers (TWINS) energetic neutral atom (ENA) images and measured by Time History of Events and Macroscale Interactions during Substorms (THEMIS) D and E during a magnetic storm on 29 May 2010 is shown. The ion intensities and energy spectra along the THEMIS path are also compared with those deconvolved from the TWINS ENA images. The global plots of the ion intensities show an asymmetric ring current in the early recovery phase consistent with the ASY/H index. The comparison between the in situ pitch angle distributions observed by THEMIS and those obtained here from TWINS ENA images lends credence to the global plots of pitch angle anisotropy provided by the TWINS data. The spatial dependence of the pitch angle anisotropy provides information relevant to ion precipitation and lifetimes of trapped ring current ions not available from in situ measurements.
Intrusive large igneous provinces below sedimentary basins: An example from the Exmouth Plateau (NW Australia)
Authors: Rohrman Max
Published: July 2013

Large igneous provinces (LIPs) are commonly characterized by extrusion of huge outpourings of flood basalts. However, some LIPs associated with thick sedimentary basins display mainly intrusive sill and dike complexes and a relative absence of extrusives as evidenced on the Exmouth Plateau. Here a breakup‐related 150 km × 400 km sill complex imaged on seismic reflection data intruded mainly Triassic sedimentary rocks between the Late Jurassic and the Early Cretaceous. The sill complex is most likely sourced by a mafic or an ultramafic magma chamber, seismically imaged as a high‐velocity body (HVB) and covering ~16 × 104 km2. This magma chamber is located at the base of the crust and did not generate extrusives. Simple hydrostatic calculations suggest that melt became vertically arrested in the basin sediments, primarily owing to a reduction in the magmatic overpressure gradient as a result of the differences between fracture and melt gradients controlled by upward decreasing densities of the basin fill. Furthermore, magma overpressures at the source between 5 and 20 MPa are required to explain the presence of sill complexes at 4–11 km depth, indicating that the HVB is the source of the sill/dike complex on the Exmouth Plateau. The extent and outline of the HVB places constraints on the origin of magmatism and LIP formation. In combination with published data, the results suggest a thermal anomaly (upwelling or plume) source for the observed magmatism.
Numerical modeling of cloud chemistry effects on isocyanic acid (HNCO)
Authors: Barth M. C. , Cochran A. K. , Fiddler M. N. , Roberts J. M. , Bililign S.
Published: July 2013

Isocyanic acid (HNCO), a product of some combustion processes, can potentially have negative human health effects. While gas phase HNCO loss processes are slow, HNCO loss in the aqueous phase is much faster. The fate of HNCO is studied for different cloud chemistry conditions using a zero‐dimensional chemical box model. Exposure to clouds reduces HNCO concentrations substantially under typical cumulus cloud conditions, resulting in the chemical lifetime of HNCO dropping to ~2 h compared to clear‐sky conditions of several years. The effect of clouds on HNCO is strongly dependent on the pH and temperature, with more HNCO hydrolyzed at lower pH (more acidic drops) and higher temperatures. Thus, HNCO is most efficiently removed by fog or low‐level stratus clouds and least efficiently removed under middle to upper troposphere conditions where cumulonimbus and pyrocumulus clouds reside. Deliquesced aerosols may be highly efficient at reducing HNCO concentrations.
Characteristics of tropospheric ozone variability over an urban site in Southeast Asia: A study based on MOZAIC and MOZART vertical profiles
Authors: Sahu L. K. , Sheel Varun , Kajino M. , Gunthe Sachin S. , Thouret Valérie , Nedelec P. , Smit Herman G.
Published: July 2013

The Measurement of Ozone and Water Vapor by Airbus In‐Service Aircraft (MOZAIC) profiles of O3 and CO were analyzed to study their variation in the troposphere over Bangkok. Mixing ratios of O3 and CO were enhanced in planetary boundary layer (PBL) being highest in winter followed by summer and wet seasons. The daytime profiles of O3 show higher values compared to nighttime observations in PBL region, but little differences were observed in the free troposphere. The decreasing mixing ratios of O3 in the lower and upper troposphere were associated with shallow and deep convections, respectively. Back trajectory and fire count data indicate that the seasonal variations in trace gases were caused mainly by the regional shift in long‐range transport and biomass‐burning patterns. In wet season, flow of oceanic air and negligible presence of local biomass burning resulted in lowest O3 and CO, while their high levels in dry season were due to extensive biomass burning and transport of continental air masses. The Model for Ozone and Related Chemical Tracers (MOZART) underestimated both O3 and CO in the PBL region but overestimated these in the free troposphere. Simulations of O3 and CO also show the daytime/nighttime differences but do not capture several key features observed in the vertical distributions. The observed and simulated values of O3 and CO during September–November 2006 were significantly higher than the same period of 2005. The year‐to‐year differences were mainly due to El Niño‐led extensive fires in Indonesia during 2006 but normal condition during 2005.
Discharge regime and simulation for the upstream of major rivers over Tibetan Plateau
Authors: Zhang Leilei , Su Fengge , Yang Daqing , Hao Zhenchun , Tong Kai
Published: July 2013

The hydrological regimes for the major river basins in the Tibetan Plateau (TP), including the source regions of the Yellow (UYE), Yangtze (UYA), Mekong (UM), Salween (US), Brahmaputra (UB), and Indus (UI) rivers, were investigated through a land surface model and regression analyses between climate variables and runoff data. A hydrologic modeling framework was established across the TP to link the Variable Infiltration Capacity (VIC) land surface hydrology model with a degree‐day glacier‐melt scheme (VIC‐glacier model) at a 1/12° × 1/12°. The model performance was evaluated over the upper basins of the six rivers. The heterogeneity and scarcity of the meteorological stations are the major limitation for hydrological modeling over the TP. The relative contributions to streamflow from rainfall, snowmelt, and glacier melt for the six basins were quantified via the model framework and simulation. The results suggest that monsoon precipitation has a dominant role in sustaining seasonal streamflow over southeastern regions, contributing 65–78% of annual runoff among the UYE, UYA, UM, US, and UB basins. For the UI, the runoff regime is largely controlled by the glacier melt and snow cover in spring and summer. The contribution of glacier runoff is minor for the UYE and UM (less than 2% of total annual flow), and moderate for the UYA and US basins (5–7% of yearly flow), while glacier melt makes up about 12% and 48% of annual flow for the UB and UI basins, respectively.
Spatial representativeness of ground‐based solar radiation measurements
Authors: Hakuba M. Z. , Folini D. , Sanchez‐Lorenzo A. , Wild M.
Published: July 2013

The validation of gridded surface solar radiation (SSR) data often relies on the comparison with ground‐based in situ measurements. This poses the question on how representative a point measurement is for a larger‐scale surrounding. We use high‐resolution (0.03°) SSR data from the Satellite Application Facility on Climate Monitoring (CM SAF) to study the subgrid spatial variability in all‐sky SSR over Europe and the spatial representativeness of 143 surface sites with homogeneous records for their site‐centered larger surroundings varying in size from 0.25° to 3°, as well as with respect to a given standard grid of 1° resolution. These analyses are done on a climatological annual and monthly mean basis over the period 2001–2005. The spatial variability of the CM SAF data set itself agrees very well with surface measurements in Europe, justifying its use for the present study. The annual mean subgrid variability in the 1° standard grid over European land is on average 1.6% (2.4 W m−2), with maximum of up to 10% in Northern Spain. The annual mean representation error of point values at 143 surface sites with respect to their 1° surrounding is on average 2% (3 W m−2). For larger surroundings of 3°, the representation error increases to 3% (4.8 W m−2). The monthly mean representation error at the surface sites with respect to the 1° standard grid is on average 3.7% (4 W m−2). This error is reduced when site‐specific correction factors are applied or when multiple sites are available in the same grid cell, i.e., three more sites reduce the error by 50%.
A Facile One Pot Synthesis of New Tricyclic Coumarins from Single Synthon [1
Authors: Kalkhambkar Rajesh G. , Kulkarni Geeta M. , Kulkarni Manohar V.
Published: July 2013

A high yielding method for the synthesis of new tricyclic coumarins is reported herein using 8‐formyl‐7‐hydroxy‐4‐methyl coumarin as a single synthon. Different strategies were employed to synthesize tricyclic coumarins fused with isoxazole and pyran at C7‐C8 position in the coumarin skeleton. Functional group modifications during the construction of pyrazolyl coumarin has resulted in novel oxidative ipso nitration. The O‐tosylate was subjected to conditions of pressure in a sealed tube experiment, since it was not possible to replace the 7‐hydroxy group of coumarin by regular methods. All the compounds synthesized during the present investigation were characterized by IR, 1H‐NMR, 13C‐NMR, ESI‐MS, and elemental analysis. The X‐ray diffraction data of some of the intermediate hydrazones are also reported herein.
Synthesis and Evaluation of Some New (1,2,4) Triazolo(4,3‐a)Quinoxalin‐4(5H)‐one Derivatives as AMPA Receptor Antagonists
Authors: Abul‐Khair Hamada , Elmeligie Salwa , Bayoumi Ashraf , Ghiaty Adel , El‐Morsy Ahmed , Hassan Memy H.
Published: July 2013

This study involves the synthesis and anticonvulsant evaluation of 1‐ethyl‐3‐hydrazinylquinoxaline‐2‐(1H)‐one (8), its chemical confirmations 9 and 10 and certain (1,2,4) triazolo(4,3‐a)quinoxalin‐4(5H)‐one compounds 11, 12, 13, 13a, 13b, 13c, 13d, 13e, 13f, 14, 15, 16. The structure of the synthesized compounds was confirmed chemically by elemental analyses and spectral data (IR, 1H NMR, 13C NMR, and Mass). Docking studies were preformed to all of the synthesized compounds to predict, in a qualitative way, the anticonvulsant activity of the proposed compounds. There is a promising correlation between the results of molecular modeling and the anticonvulsant activity of the synthesized compounds. The highest fitting value was noticed for compounds 9 and 10, which showed the highest anticonvulsant activity.
Synthesis of 3,4‐Dihydropyrimidinones via Phase Transfer Catalysis
Authors: Moussaoui Younes , Salem Ridha Ben
Published: July 2013

3,4‐Dihydropyrimidinone and derivatives were synthesized by the one‐pot, three‐component Biginelli condensation of an aldehyde, β‐dicarbonyl compound and urea. Synthesis was carried out in aqueous sodium hydroxide using Aliquat‐336 as a phase transfer agent. Compared to the classical Biginelli reaction conditions, this new method cousistently has the advantage of excellent yields and short reaction time.
The psychological structure of aggression across cultures
Authors: Severance Laura , Bui‐Wrzosinska Lan , Gelfand Michele J. , Lyons Sarah , Nowak Andrzej , Borkowski Wojciech , Soomro Nazar , Soomro Naureen , Rafaeli Anat , Efrat Treister Dorit , Lin Chun‐Chi , Yamaguchi Susumu
Published: July 2013

To date, the vast majority of the research on aggression has been conducted on Western samples. This research expands the culture‐bound understanding of aggression by examining universal and culture‐specific dimensions that underlie the psychological structure of aggression. Drawing on cultural logics of honor, dignity, and face, we examine the construal of aggression across Pakistan, Israel, Japan, and the United States. Multidimensional scaling analyses revealed potentially universal dimensions of aggression. In all four nations, dimensions of damage to self‐worth and direct versus indirect aggression emerged, and a physical versus verbal aggression emerged in Pakistan, Israel, and Japan. In addition, an infringement to personal resources dimension emerged in the United States and Israel, and a degree of threat dimension emerged in Pakistan. Further, results demonstrated cultural specificity in terms of (i) where aggressive behaviors fell along each dimension and (ii) meanings that defined each dimension across cultures. These findings have implications for the prevention and attenuation of intercultural conflicts as well as the advancement of the cross‐cultural psychology and the aggression literatures. Copyright © 2013 John Wiley & Sons, Ltd.
Interactive effects of levels of individualism–collectivism on cooperation: A meta‐analysis
Authors: Marcus Justin , Le Huy
Published: July 2013

We examined the interactive effects of levels of individualism–collectivism (I–C) on cooperation at work by meta‐analytically combining results obtained from 201 studies, representing 225 independent samples. I–C was operationalized at the individual, organizational, and societal levels of analyses. Cooperation was conceptualized at both individual and group levels of analysis. Both cooperative behavior and performance were included as outcomes. The correlation between individual‐level I–C and cooperation/performance was stronger in collectivistic as opposed to individualistic societies. Similarly, the correlation between organizational‐level I–C and cooperation was stronger in collectivistic societies. Results also indicated that individual‐level and organizational‐level I–C, but not societal‐level I–C, were moderately related to study outcomes. Examination of other potential moderators indicated that neither study setting, I–C dimensionality, nor performance measurement type (objective vs subjective measures) altered these relations. However, a conceptual match between I–C and cooperation was a moderator such that effect sizes were generally larger when I–C and outcomes were both measured at the same level of analysis. Overall, our results indicate that I–C is both theoretically and empirically distinct across the various levels of analyses and that it may be a better predictor of outcomes in collectivistic as opposed to individualistic societies. Copyright © 2013 John Wiley & Sons, Ltd.
Metal presence in hair after metal‐on‐metal resurfacing arthroplasty
Authors: Rodríguez de la Flor María , Hernández‐Vaquero Daniel , Fernández‐Carreira José Manuel
Published: July 2013

The elevation of metal levels in serum and urine during post‐operative follow‐up is a frequent find following the implantation of certain models of metal‐on‐metal hip prostheses. Among 45 patients with the same resurfacing prostheses, chromium (Cr) and cobalt (Co) levels in serum and urine were determined at 3, 4, 5, and 6 years after surgery. In the same period, levels of Cr, Co and molibdene (Mo) in scalp hair were also measured. Mean Cr and Co levels in serum were 8.29 µg/L (SD 17.97) and 8.38 µg/L (SD 21.97), respectively, whereas in urine levels were 16.20 µg/L (SD SD 32.55) and 75.40 µg/L (SD 190.86), respectively. In hair, mean Cr level were 163.27 µg/g (SD 300.62), mean Co level 61.98 µg/g (SD 126.48), and Mo 31.36 µg/g (SD 37.86). A high concordance was observed between chromium‐urine and chromium‐serum and between cobalt‐urine and cobalt‐hair. A moderate concordance was present between cobalt‐urine and cobalt‐serum, and between cobalt‐hair and cobalt‐serum. Eleven patients required revision surgery, five of them due to metallosis and periarticular cyst. At 1 year after reintervention, analytics were performed again and the following decrease rates were found: 42.8% in Cr levels, 51.1% in Mo levels, and 90.3% in Co levels. © 2013 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 31:2025–2031, 2013
Comparative digestibility of energy and nutrients and fermentability of dietary fiber in eight cereal grains fed to pigs
Authors: Cervantes‐Pahm Sarah K , Liu Yanhong , Stein Hans H
Published: July 2013

BACKGROUND

Cereal grains provide a large portion of caloric intake in diets for humans, but not all cereal grains provide the same amount of energy. Therefore, an experiment was conducted to determine and compare the metabolizable energy (ME), the apparent ileal digestibility (AID), and the apparent total tract digestibility (ATTD) of gross energy (GE) and nutrients in eight cereal grains when fed to pigs.

RESULTS

Rice had greater (P < 0.05) AID of GE than other cereal grains, greater (P < 0.05) AID of starch than yellow dent corn, dehulled barley, rye, and wheat, and greater (P < 0.05) ATTD of GE than yellow dent corn, rye, sorghum, and wheat. Dehulled barley, rye, and sorghum had less (P < 0.05) AID of starch than other cereal grains. Dehulled barley had greater (P < 0.05) ATTD of GE than rye. Dehulled oats had the greatest (P < 0.05) ME compared with other cereal grains, whereas rye had the least (P < 0.05) ME.

CONCLUSION

Dehulled oats provide more energy to diets and should be used if the goal is to increase caloric intake. In contrast, sorghum and rye may be more suitable to control diabetes and manage body weight of humans. © 2013 Society of Chemical Industry
Enzyme‐assisted extraction of cactus bioactive molecules under high hydrostatic pressure
Authors: Kim Jae Hwan , Park Yooheon , Yu Kwang Won , Imm Jee‐Young , Suh Hyung Joo
Published: July 2013

BACKGROUND

To improve the extraction and recovery of bioactive materials from cactus, the present study investigated the effect of polysaccharide‐degrading enzymes [Rapidase–Viscozyme mixture, 1/3 (v/v)] treatment under high hydrostatic pressure (HHP).

RESULTS

The dry weight of the extract increased with the use of increasing pressure regardless of enzyme treatment. However, the polyphenol content showed a tendency to decrease with the increase in pressure in the cactus extract with or without enzyme treatment. The enzyme‐assisted extraction resulted in an increase of dry weight and polyphenol content in the cactus extract. The total sugar and reducing sugar contents of the cactus extract increased with increasing pressure in enzyme‐assisted extraction. The uronic acid content of the cactus extract showed a pattern similar to that of the reducing sugars. The enzyme‐assisted extraction also increased the contents of taxifolin, quercetin and isorhametin. The cactus extract obtained through enzyme‐assisted extraction showed intense scavenging activity of both DPPH and ABTS radicals. The crude polysaccharides isolated from the extract (51.2% at 1000 µg mL−1 for HHP extraction at 300 MPa) had higher anti‐complementary activity than the others except for lipopolysaccharide (60.00% at 1000 µg mL−1). HHP extraction and enzyme‐assisted extraction using HHP showed an increase of anti‐complementary activity compared with the heat and enzyme controls, respectively.

CONCLUSION

Overall, the use of HHP in enzyme‐assisted extraction resulted in more efficient extraction than the use of enzyme treatment alone. © 2013 Society of Chemical Industry
Bridge‐Splitting Reactions of Platinum(II) Complexes with Parametalated Pyridine Spacer Groups: A Kinetic and Mechanistic Study
Authors: Ongoma Peter O. , Jaganyi Deogratius
Published: July 2013

Substitution reactions of three dinuclear Pt(II) complexes connected by a pyridine‐bridging ligand of variable length, namely [ cis‐{PtOH2(NH3)2}2–μ–L]4+, where L = 4,4′‐bis(pyridine)sulfide (Pt1), 4,4′‐bis(pyridine)disulfide (Pt2), and 1,2‐bis(4‐pyridyl)ethane (Pt3) with S‐donor nucleophiles (thiourea, 1,3‐dimethyl‐2‐thiourea, and 1,1,3,3‐tetramethyl‐2‐thiourea) and anionic nucleophiles (SCN−, I−, and Br−) were investigated. The substitutions were followed under pseudo–first‐order conditions as a function of the nucleophile concentration and temperature, using stopped‐flow and UV–visible spectrophotometric methods. The observed pKavalues were, respectively,Pt1(pKa1: 4.86; pKa2: 5.53),Pt2(pKa1: 5.19; pKa2: 6.42), andPt3(pKa1: 5.04; pKa2: 5.45). The second‐order rate constants for the lability of aqua ligands in the first step decreased in the orderPt2>Pt3>Pt1, whereas for the second step it isPt1>Pt2>Pt3. The obtained results indicate that introduction of a spacer atom(s) on the structure of the bridging ligand influences the substitution reactivity as well as acidity of the investigated dinuclear Pt(II) complexes. Also nonplanarity of the bridging ligand ofPt1complex significantly slows down the rate of substitution due to steric hindrance, whereas release of the strain enhances the dissociation of the bridging ligand. The release of the bridging ligand in the second step was confirmed by the1H NMR ofPt1‐Clwith thiourea in DMF‐d7. The temperature dependence of the second–order rate constants and the negative values of entropies of activation (ΔS#) support an associative mode of the substitution mechanism.
Continuous Production of Flexible Fibers from Transgenically Produced Honeybee Silk Proteins
Authors: Poole Jacinta , Church Jeffrey S. , Woodhead Andrea L. , Huson Mickey G. , Sriskantha Alagacone , Kyratzis Ilias L. , Sutherland Tara D.
Published: July 2013

Flexible and solvent stable fibers are produced after concentrated recombinant honeybee protein solutions are extruded into a methanol bath, dried, drawn in aqueous methanol, then covalently cross‐linked using dry heat. Proteins in solution are predominantly coiled coil. Significant levels of non‐orientated ß‐sheets form during drying or after coagulation in aqueous methanol. Drawing generally aligns the coiled coil component parallel with the fibre axis and ß‐sheet component perpendicular to the fiber axis. The fibres are readily handled, stable in the strong protein denaturants, urea and guanidinium, and suitable for a range of applications such as weaving and knitting.
In Situ Monitoring of the Reaction‐Induced Self‐Assembly of Phenolic Resin Templated by Diblock Copolymers
Authors: Li Jheng‐Guang , Chu Wei‐Cheng , Jeng U.‐Ser , Kuo Shiao‐Wei
Published: July 2013

In this study, in situ small‐angle X‐ray scattering (SAXS), in situ Fourier transform infrared (FTIR) spectroscopy, and transmission electron microscopy (TEM) are used to monitor the formation of ordered mesophases in cured mixtures of phenolic resin and the diblock copolymer poly(ethylene oxide‐block‐ε‐caprolactone) (PEO‐b‐PCL). SAXS and TEM analyses reveal that the mesophase of the phenolic/PEO‐b‐PCL mixture transforms sequentially from disordered to short‐range‐ordered to hexagonal‐cylindrical to gyroidal during the curing process when using hexamethylenetetramine (HMTA) as a cross‐linking agent, indicating that a mechanism involving reaction‐induced microphase separation controls the self‐assembly of the phenolic resin. In situ SAXS is also used to observe the fabrication of mesoporous phenolic resins during subsequent calcination processes.

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Medicinal Chemistry of Fluorinated Cyclic and Acyclic Nucleoside Phosphonates
Authors: Baszczyňski Ondřej , Janeba Zlatko
Published: July 2013

The fluorine atom plays an important role in medicinal chemistry because fluorine substitution has a strong impact on the physical, chemical, and biological properties of bioactive compounds. Such fluorine modifications have also been extensively studied among the pharmaceutically important class of nucleoside phosphonates, nucleotide analogues in which the phosphate group is replaced by the enzymatically and chemically stable phosphonate moiety. The fluorinated nucleoside phosphonates abound with antiviral, antiparasitic, and anticancer properties because they are able to act as inhibitors of important enzymes of nucleoside/nucleotide metabolism. In this paper, we review the biological properties of cyclic and acyclic nucleoside phosphonates modified by the attachment of one or more fluorine atoms to various parts of the molecule, namely to nucleobases, alkylphosphonate groups, cyclic or acyclic linkers, or to prodrug moieties.
Epigenetic effects of natural polyphenols: A focus on SIRT1‐mediated mechanisms
Authors: Ayissi Vincent B. Owona , Ebrahimi Azadeh , Schluesenner Hermann
Published: July 2013

Polyphenols are a class of natural compounds widely distributed in fruits, vegetables, and plants. They have been reported to possess a wide range of activities in prevention and alleviation of various diseases like cancer, neuroinflammation, diabetes, and aging. Polyphenols are effective against chronic diseases and recent reports indicated strong epigenetic effects of polyphenols. Most of the studies investigating epigenetic effects of natural polyphenols have focused on their beneficial effects in cancer treatment. However, epigenetic defects have been demonstrated in many other diseases as well, and application of polyphenols to modulate the epigenome is becoming an interesting field of research. This review summarizes the effects of natural polyphenols in modulating epigenetic‐related enzymes as well as their effect in prevention and treatment of chronic diseases with a focus on SIRT1 modulation. We have also discussed the relation between the structure and function of epigenetic‐modifying polyphenols.
Self‐organizing femtocell offloading at the flow level
Authors: Akbarzadeh Sara , Combes Richard , Altman Zwi
Published: July 2013

Femtocell technology is expected to be fully self‐managed, empowered by self‐organizing network functionalities. This paper proposes a solution for self‐optimized offloading of macrocell traffic towards open/hybrid‐access femtocells. A heterogeneous network comprising macro‐ and femtocells is modeled as parallel queues. The coverage area of the femtocells is self‐optimized by dynamically adapting their pilot powers. A simple update equation for the pilot power is given and its convergence is studied using stochastic approximation techniques. The algorithm balances the load among the cells to improve network capacity. Simulation results illustrate the important performance gains brought about by the proposed scheme, using a dynamic network simulator. Copyright © 2013 John Wiley & Sons, Ltd.
Proper orthogonal decomposition‐based model order reduction via radial basis functions for molecular dynamics systems
Authors: Lee Chung‐Hao , Chen Jiun‐Shyan
Published: July 2013

Model order reduction for molecular dynamics (MD) systems exhibits intrinsic complexities because of the highly nonlinear and nonlocal multi‐atomic interactions in high dimensions. In the present work, we introduce a proper orthogonal decomposition‐based method in conjunction with the radial basis function (RBF) approximation of the nonlinear and nonlocal potential energies and inter‐atomic forces for MD systems. This approach avoids coordinate transformation between the physical and reduced‐order coordinates, and allows the potentials and inter‐atomic forces to be calculated directly in the reduced‐order space. The RBF‐approximated potential energies and inter‐atomic forces in the reduced‐order space are discretized on the basis of the Smolyak sparse grid algorithm to further enhance the effectiveness of the proposed method. The good approximation properties of RBFs in interpolating scattered data make them ideal candidates for the reduced‐order approximation of MD inter‐atomic force calculations. The proposed approach is validated by performing the reduced‐order simulations of DNA molecules under various external loadings. Copyright © 2013 John Wiley & Sons, Ltd.
Novel amphiphilic conetworks based on compatibilized NBR/SBR–montmorillonite nanovulcanizates as membranes for dehydrative pervaporation of water–butanol mixtures
Authors: Essawy Hisham , Tawfik Magda , El‐Sabbagh Salwa , El‐Gendi Ayman , El‐Zanati Elham , Abdallah Heba
Published: July 2013

Nanocomposite vulcanizates comprising the poorly compatible acrylonitrile butadiene rubber/styrene butadiene rubber blend are homogenized with 20 parts per hundred montmorillonite forms showing various levels of amphiphathicity: slightly hydrophobic (Mont‐25/50) and highly hydrophobic (Mont75/100) as compared to the highly hydrophilic pristine form (Mont‐0). The purpose of the amphiphathicity is to afford simultaneous binding sites for the poorly compatible components. Thus maximum compatibility is reached with either Mont‐75 or Mont‐50 which improves the mechanical properties. Scanning electron microscopy corroborates cocontinuous morphology. Water vapor permeation through sheets/membranes fabricated from these compositions follows best performance with Mont‐25 followed by Mont‐50 while Mont‐75 and Mont‐100 based membranes acquire an organized continuous drop. This highlights the role of organophilicity in dominating the morphology and performance in pervaporation application. Dehydration of butanol is effective using such membranes with superiority for Mont‐25 based membrane. A plausible model for the transport mechanism was proposed and supported by activation energy calculations for the permeation of the individual components and the sorption affinity measurements as well. All these parameters together suggest the arrest of the n‐butanol within the macrmolecular chains of the membranes, favored by its chemical affinity. This allows therefore a passageway for the water to cross to the other side of the membrane through plasticization of the chains and creation of free volumes which is known as solution diffusion mechanism. POLYM. ENG. SCI., 54:1560–1570, 2014. © 2013 Society of Plastics Engineers
Understanding the relevance of local conformational stability and dynamics to the aggregation propensity of an IgG1 and IgG2 monoclonal antibodies
Authors: Thakkar Santosh V. , Sahni Neha , Joshi Sangeeta B. , Kerwin Bruce A. , He Feng , Volkin David B. , Middaugh C. Russell
Published: July 2013

Aggregation of monoclonal antibodies is often a multi‐step process involving structural alterations in monomeric proteins and subsequent formation of soluble or insoluble oligomers. The role of local conformational stability and dynamics of native and/or partially altered structures in determining the aggregation propensity of monoclonal antibodies, however, is not well understood. Here, we investigate the role of conformational stability and dynamics of regions with distinct solvent exposure in determining the aggregation propensity of an IgG1 and IgG2 monoclonal antibody. The temperatures employed span the pre‐unfolding range (10–40°C) and the onset temperatures (Tonset) for exposure of apolar residues (∼50°C), alterations in secondary structures (∼60°C) and initiation of visible aggregate formation (∼60°C). Solvent‐exposed regions were found to precede solvent‐shielded regions in an initiation of aggregation for both proteins. Such a process was observed upon alterations in overall tertiary structure while retaining the secondary structures in both the proteins. In addition, a greater dynamic nature of solvent‐shielded regions in potential intermediates of IgG1 and the improved conformational stability increased its resistance to aggregation when compared to IgG2. These results suggest that local conformational stability and fluctuations of partially altered structures can influence the aggregation propensity of immunoglobulins.
Influence of surface misorientation of HPHT diamond substrates on crystal morphologies and threading dislocations propagation
Authors: Naamoun M. , Tallaire A. , Achard J. , Silva F. , William L. , Doppelt P. , Gicquel A.
Published: July 2013

The production of diamond‐based electronic devices for optical and electronic applications requires the control of point and extended defects that influence the exceptional properties of the material. While point defects in single crystal (Chemical Vapor Deposition) diamond have been studied for many years, relatively little has been reported on the extended defects content of this material. In particular, threading dislocations propagating parallel to the growth direction, act as killer defects within the CVD diamond film. In this work, different substrate surface misorientations have been investigated to evaluate their effect on dislocation propagation. Misorientation angles of 3.5°, 10°, and 20° along <100> and <110> directions as well as bevels of 10° along <100> and <110> directions were used. By using misorientations of 10° or above along the <110> directions it is possible to plasma etch the substrate surface prior to growth while keeping a smooth morphology. This affects defect density in the CVD film after growth and helps decreasing threading dislocations. In parallel, a growth model allowed us to predict the evolution of the top misoriented face and the crystal shape. This study aims at getting a better understanding of dislocations formation and propagation in order to prepare defect‐free CVD diamond films.
Electrical Biomolecule Detection Using Nanopatterned Silicon via Block Copolymer Lithography
Authors: Jeong Chang Kyu , Jin Hyeong Min , Ahn Jae‐Hyuk , Park Tae Jung , Yoo Hyeon Gyun , Koo Min , Choi Yang‐Kyu , Kim Sang Ouk , Lee Keon Jae
Published: July 2013

An electrical biosensor exploiting a nanostructured semiconductor is a promising technology for the highly sensitive, label‐free detection of biomolecules via a straightforward electronic signal. The facile and scalable production of a nanopatterned electrical silicon biosensor by block copolymer (BCP) nano­lithography is reported. A cost‐effective and large‐area nanofabrication, based on BCP self‐assembly and single‐step dry etching, is developed for the hexagonal nanohole patterning of thin silicon films. The resultant nanopatterned electrical channel modified with biotin molecules successfully detects the two proteins, streptavidin and avidin, down to nanoscale molarities (≈1 nm). The nanoscale pattern comparable to the Debye screening length and the large surface area of the three‐dimensional silicon nanochannel enable excellent sensitivity and stability. A device simulation confirms that the nanopatterned structure used in this work is effective for biomolecule detection. This approach relying on the scalable self‐assembly principle offers a high‐throughput manufacturing process for clinical lab‐on‐a‐chip diagnoses and relevant biomolecular studies.
Composite Pellets – A Potential Raw Material for Iron‐Making
Authors: Ahmed Hesham M. , Viswanathan Nurni , Bjorkman Bo
Published: July 2013

Coke constitutes the major portion of iron‐making cost and its production causes severe environmental concerns. In addition, lower energy consumption, lower CO2 emission and waste recycling are driving the Iron and steel making industry to develop “coke free, zero waste or green processes”. In the present article, an overview of possible ways to recognize a reasonable improvement in iron and steel making industry is summarized. The present discussion is focusing on the following approaches:

Replacing expensive coke with relatively less expensive alternate fuels having carbon as well as significant amount of hydrogen such as coal, waste plastic and biomass materials.

Producing agglomerates from cheaper raw materials (secondary resources) as well as improving their performance in BF.

Making the process towards higher carbon utilization by shifting the wustite equilibrium towards lower CO/CO2 ratio by using high reactive coke or catalytic activated one.

Recycling the unused CO in the top gas by removing CO2 from the gas stream.

Much attention has been paid to carbon composite agglomerates (CCA) as a promising raw material for future iron making. Production, mechanical and chemical suitability, reduction behavior, etc. are being elaborated. In addition, other possible ways to utilize CCA in alternate iron‐making process has been explored.
Numerical, Physical, and Industrial Experiments of Liquid Steel Mixture in One Strand Slab Tundish with Flow Control Devices
Authors: Cwudziński Adam
Published: July 2013

The paper presents investigation results related to a tundish furnished with a flow control devices (FCD). The facility under investigation is a one‐strand tundish used for casting concast slabs. To evaluate the influence of FCDs on the pattern of liquid steel flow, an industrial and a laboratory experiments (physical and numerical simulation) were carried out. In collaboration with Vesuvius, a refractory materials manufacturer, and the ISD Czestochowa Steelworks Ltd., pilot industrial tests were carried out. Based on data acquired from the industry, a glass tundish model on a scale of 1:2.5 was made. A tundish in the form of virtual models was prepared for numerical simulations using the Gambit 2.4 software program. Commercial software Ansys‐Fluent® was used for solving the mathematical model of the liquid steel flow. From the industrial and laboratory experiments, results were obtained, which provided a basis for plotting curves describing the steel mixing process in the tundish. In addition, the computer simulations provided also a valuable source of information about the flow directions, flow intensity and temperature of the liquid steel, represented in the form of maps.
Effectiveness and efficiency of support schemes for electricity from renewable energy sources
Authors: Ragwitz Mario , Steinhilber Simone
Published: July 2013

A variety of support schemes for renewable energy sources in the electricity sector (RES‐E) are currently being implemented in EU member states. The main tools used for this purpose are either price‐based policy instruments such as feed‐in tariffs or premiums, or quantity‐based instruments such as quota systems using tradable green certificates. Much work has been devoted to the motivation for and evaluation of these instruments, mostly in the form of country/local case studies, model simulations, or econometric modeling. The main drivers behind these policies are addressing the externalities of the environmentally harmful emissions of electricity generation and stimulating technological innovation. Two frequently used evaluation criteria for support schemes and instruments are their effectiveness and economic efficiency. We find that those support schemes, which are most effective in stimulating the growth of RES‐E generation, are typically economically efficient as well. Generally, it can be concluded that support schemes, which are technology specific, and those that avoid unnecessary risks in project revenues, are more effective and efficient than technology‐neutral support schemes, or schemes with higher revenue risk. The most recent quantitative assessment shows that some convergence can now be observed between schemes applying price‐ and quantity‐based instruments. With respect to policy effectiveness, quota schemes show improvements. Regarding efficiency, the situation is still very heterogeneous, and remuneration levels in many EU member states are still substantially higher than generation costs.

This article is categorized under:

Energy Infrastructure > Economics and Policy

Energy Infrastructure > Systems and Infrastructure

Energy Infrastructure > Climate and Environment

Energy Systems Economics > Economics and Policy
Protein nanomachines assembly modes: cell‐free expression and biochip perspectives
Authors: Daube Shirley S. , Bar‐Ziv Roy H.
Published: July 2013

Large macromolecular assemblies are widespread in all cell types with diverse structural and functional roles. Whether localized to membranes, nuclei, or cytoplasm, multimeric protein–nucleic acid complexes may be viewed as sophisticated nanomachines, an inspiration to chemical design. The formation of large biological assemblies follows a complex and hierarchical self‐assembly process via ordered molecular recognition events. Serving a paradigm for biological assembly, extensive past studies of T4 bacteriophage and bacterial ribosomes by many groups have been revealing distinct design strategies, yet these two very different multimeric complexes share common mechanistic motifs. An emerging biochip approach highlights two conceptual notions to promote the study of assembly pathways: cell‐free expression provides coupling between synthesis and assembly; surface anchoring allows high‐resolution imaging of structural intermediates and opens up opportunities for rewiring a network by defining unnatural scaffolds for synthetic design applications. WIREs Nanomed Nanobiotechnol 2013, 5:613–628. doi: 10.1002/wnan.1227

This article is categorized under:

Nanotechnology Approaches to Biology > Nanoscale Systems in Biology
Chemical effects of high‐resolution YbLγ4 emission spectra: a possible probe for chemical analysis
Authors: Hayashi Hisashi , Kanai Noriko , Kawamura Naomi , Matsuda Yasuhiro H. , Kuga Kentaro , Nakatsuji Satoru , Yamashita Tetsuro , Ohara Shigeo
Published: July 2013

An ‘eccentric’ X‐ray emission, YbLγ4, was measured for Yb metal, Yb2O3, YbF3, β‐YbAlB4, YbNi3Al9, and YbNi3Ga9 with a resolution of ~0.9 eV. Peak splitting of the YbLγ4 line was observed in all the recorded spectra and was attributed to the two components originating from the LS coupling of the Yb5p hole, the Yb5p1/2 (LIOII: Lγ4′) and Yb5p3/2 components (LIOIII: Lγ4). The spectra were substantially different depending on the chemical environment of Yb. The position of the Lγ4 + Lγ4′ band shifts depending on the valence of Yb (v): ~4.4 eV from divalent to trivalent. The Lγ4 + Lγ4′ spectra of the mixed valence intermetallics, i.e. YbNi3Ga9 (v = 2.59) and β‐YbAlB4 (v = 2.75), were fairly well reproduced by averaging the spectra of divalent Yb and trivalent YbNi3Al9, which suggests the possibility of using the YbLγ4 emission for determining the valence of Yb intermetallics. In trivalent Yb compounds, the relative intensity of Lγ4 compared with that of Lγ4′, as well as the appearance of a high‐energy satellite, was found to be influenced by the ligands around the Yb ions. With the aid of preliminary atomic multiplet and band structure calculations, the differences in the valence band structure and resultant screening effects on the OII,III−1 states were determined to be the possible causes for the observed ligand dependence. © 2013 The Authors. X‐ray spectrometry published by John Wiley & Sons, Ltd.
The fate of monsters in anti-de Sitter spacetime
Authors: Ong Yen Chin , Chen Pisin
Published: July 2013

Abstract

Black hole entropy remains a deep puzzle: where does such enormous amount of entropy come from? Curiously, there exist gravitational configurations that possess even larger entropy than a black hole of the same mass, in fact, arbitrarily high entropy. These are the so-called monsters, which are problematic to the Anti-de Sitter/Conformal Field Theory (AdS/CFT) correspondence paradigm since there is far insufficient degrees of freedom on the field theory side to account for the enormous entropy of monsters in AdS bulk. The physics of the bulk however may be considerably modified at semi-classical level due to the presence of branes. We show that this is especially so since monster spacetimes are unstable due to brane nucleation. As a consequence, it is not clear what the final fate of monsters is. We argue that in some cases there is no real threat from monsters since although they are solutions to Einstein’s Field Equations, they are very likely to be completely unstable when embedded in string theory, and thus probably are not solutions to the full quantum theory of gravity. Our analysis, while suggestive and supportive of the claim that such pathological objects are not allowed in the final theory, by itself does not rule out all monsters. We comment on various kin of monsters such as the “bag-of-gold” spacetime, and also discuss briefly the implications of our work to some puzzles related to black hole entropy.
Aspirin Use is Associated with Lower Prostate Cancer Risk in Male Carriers of BRCA Mutations
Authors: Cossack Matthew , Ghaffary Cameron , Watson Patrice , Snyder Carrie , Lynch Henry
Published: July 2013

Previous studies have shown that male BRCA mutation carriers stand at increased risk of developing prostate cancer and have concerns about developing cancer. Genetic counseling practitioners often discuss strategies for reducing the risk of cancer for patients at high risk due to their genetic background. Addressing modifiable health habits is one such strategy. Unfortunately, modifiable risk factors for prostate cancer have only been documented in the general population and have not yet been studied in the BRCA carrier subpopulation. Therefore, this study aimed to identify modifiable risk factors for prostate cancer in BRCA carriers. We examined prostate cancer risk factors in 74 men who were part of families with a BRCA mutation. This study examined nine dichotomous variables including: exercise, history of vasectomy, smoking history, alcohol use, finasteride use, statin use, aspirin use, coffee use, and vitamin use. The survey was sent to all cases of prostate cancer in the Hereditary Cancer Center Database at Creighton University with a known BRCA status. This study confirmed the protective benefits of daily aspirin use, which have been observed in previous studies of the general population, and suggests its benefit in BRCA carriers. Protective benefits from regular vigorous exercise and daily coffee use trended towards significance, but neither factor withstood the Bonferroni Correction for multiple comparisons.