bluuebunny/crossref_metadata_2025 huggingface dataset:
RBE4 cells are highly resistant to paraquat‐induced cytotoxicity: studies on uptake and efflux mechanisms
Authors: Vilas‐Boas V. , Silva R. , Guedes‐de‐Pinho P. , Carvalho F. , Bastos M. L. , Remião F.
Published: October 2013

Paraquat (PQ) is a widely used, highly toxic and non‐selective contact herbicide, which has been associated with central neurotoxic effects, namely the development of Parkinson's disease, but whose effects to the blood–brain barrier (BBB) itself have rarely been studied. This work studied the mechanisms of PQ uptake and efflux in a rat's BBB cell model, the RBE4 cells. PQ is believed to enter cells using the basic or neutral amino acid or polyamine transport systems or through the choline‐uptake system. In contrast, PQ efflux from cells is reported to be mediated by P‐glycoprotein. Therefore, we evaluated PQ‐induced cytotoxicity and the effect of some substrates/blockers of these transporters (such as arginine, L‐valine, putrescine, hemicholinium‐3 and GF120918) on such cytotoxicity. RBE4 cells were shown to be extremely resistant to PQ after 24 h of exposure; even at concentrations as high as 50 mM approximately 45% of the cells remained viable. Prolonging exposure until 48 h elicited significant cytotoxicity only for PQ concentrations above 5 mM. Although hemicholinium‐3, a choline‐uptake system inhibitor, significantly protected cells against PQ‐induced toxicity, none of the effects were observed for arginine, L‐valine or putrescine. Meanwhile, inhibiting the efflux pump P‐glycoprotein using GF120918 significantly enhanced PQ‐induced cytotoxicity. In conclusion, PQ used the choline‐uptake system, instead of the transporters for the basic or neutral amino acids or for the polyamines, to enter RBE4 cells. P‐glycoprotein extrudes PQ back to the extracellular medium. However, this efflux mechanism only partially explains the observed RBE4 resistance to PQ. Copyright © 2013 John Wiley & Sons, Ltd.
A novel copper/polydimethiylsiloxane nanocomposite for copper‐containing intrauterine contraceptive devices
Authors: Xu X. X. , Ding M. H. , Zhang J. X. , Zheng W. , Li L. , Zheng Y. F.
Published: October 2013

In this article, a novel composite of copper (Cu) nanoparticles and polydimethiylsiloxane (PDMS) has been prepared and investigated for the potential application in Cu‐containing intrauterine device. The Cu/PDMS composite with various mass fraction of Cu nanoparticles was fabricated via the hot vulcanizing process. The chemical structures and surface morphologies of the Cu/PDMS composites were characterized confirming the physical interaction between Cu nanoparticles and PDMS. The surface morphology observation using scanning electron microscope and atomic force microscope showed the agglomeration of Cu nanoparticles in PDMS matrix and the distribution of the agglomerations was more uniform with increased amount of Cu nanoparticles. The cupric ion release behaviors of the Cu/PDMS composites with different amounts of Cu nanoparticles were investigated in simulated uterine fluid at 37°C for 150 days. The corrosion morphologies of the Cu/PDMS composites were also characterized. Both the burst release rate of the cupric ion in the first few days and the steady release rate after 30‐day immersion were improved. The cytotoxicity test has been done for the Cu/PDMS composites. © 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 101B: 1428–1436, 2013.
Osteocyte density in the peri‐implant bone of implants retrieved after different time periods (4 weeks to 27 years)
Authors: Piattelli Adriano , Artese Luciano , Penitente Enrico , Iaculli Flavia , Degidi Marco , Mangano Carlo , Shibli Jamil Awad , Coelho Paulo G , Perrotti Vittoria , Iezzi Giovanna
Published: October 2013

Bone tissue is characterized by a constant turnover in response to mechanical stimuli, and osteocytes play an essential role in bone mechanical adaptation. However, little to no information has been published regarding osteocyte density as a function of implantation time in vivo. The aim of this retrospective histological study was to evaluate the osteocyte density of the peri‐implant bone in implants retrieved because of different reasons in a time period from 4 weeks to 27 years. A total of 18 samples were included in the present study. Specimens were divided into 3 groups depending on the loading history of the implants: loading between 4 weeks and 7 months (group 1); loading between 1 and 5 years (group 2); loading between 14 and 27 years (group 3). All the samples were histologically evaluated and osteocyte density was obtained using the ratio of the number of osteocytes to the bone‐area (mm2). The osteocyte density values significantly increased in the Group 2 (1–5 years) compared with Group 1 (4 weeks–7 months), and significantly decreased in the Group 3 (14–27 years) compared to Group 2. No significant differences were detected between Group 1 and Group 3. The decrease in osteocyte density observed in samples that were in vivo for long periods of time under loading is possibly because of the fact that once the bone structure is well aligned and biomechanically competent, a lower number of osteocytes are necessary to keep the tissue homeostasis under loading. © 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 102B: 239–243, 2014.
Injectable biphasic calcium phosphate cements as a potential bone substitute
Authors: Sariibrahimoglu Kemal , Wolke Joop G. C. , Leeuwenburgh Sander C. G. , Yubao Li , Jansen John A.
Published: October 2013

Apatitic calcium phosphate cements (CPCs) have been widely used as bone grafts due to their excellent osteoconductive properties, but the degradation properties are insufficient to stimulate bone healing in large bone defects. A novel approach to overcome the lack of degradability of apatitic CPC involves the development of biphasic CPCs (BCPC) based on tricalcium phosphate (TCP) in both α‐ and β‐polymorphs. The aim of the current study was to prepare and analyze the physicochemical properties of BCPCs based on dual phase α/β‐TCP as obtained by heat treatment of pure α‐TCP. The handling and mechanical characteristics of the samples as well as the degradation behavior under in vitro condition were investigated and compared with a standard monophasic α‐TCP‐based CPC. The results showed that different heat treatments of commercially available α‐TCP allowed the formation of biphasic calcium phosphate powder with a variety of α/β‐TCP ratios. The use of biphasic powder particles as a reactant for CPCs resulted into increased setting and injectability times of the final BCPCs. During hardening of the cements, the amount of apatite formation decreased with increasing β‐TCP content in the biphasic precursor powders. The morphology of the monophasic CPC consisted of plate‐like crystals, whereas needle‐like crystals were observed for BCPCs. In vitro degradation tests demonstrated that dissolution rate and corresponding calcium release from the set cements increased considerably with increasing β‐TCP content, suggesting that apatitic CPCs can be rendered degradable by using biphasic α/β‐TCP as powder precursor phase. © 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 102B: 415–422, 2014.
The in vivo effect of P‐15 coating on early osseointegration
Authors: Coelho Paulo G. , Teixeira Hellen S. , Marin Charles , Witek Lukasz , Tovar Nick , Janal Malvin N. , Jimbo Ryo
Published: October 2013

The aim of this study was to evaluate mechanically and morphologically the effect of a specific peptide sequence P‐15, when incorporated into implant surfaces. Three types of implants were used for the study: Group A: commercially pure titanium implant (blasted and acid etched) + electrochemical thin calcium phosphate deposition, Group B: commercially pure titanium implant (blasted and acid etched) + electrochemical thin calcium phosphate deposition + P‐15 incorporation, and as control, Group C: commercially pure titanium implant (blasted and acid etched). After a topographical characterization, transcortical osteotomies were made, and all implant groups (102 implants per group) were randomly placed bilaterally in the tibiae of adult beagle dogs (n = 24). At, 1, 2, and 4 weeks post‐surgery, the animals were sacrificed and the samples were retrieved for removal torque tests, for nano indentation, and for histomorphometrical analysis. The results (mean ± 95% CI) showed that Group B (34.4 ± 8.7%) presented statistically higher bone‐to‐implant contact than the other groups (A = 23.9 ± 7.8%; C = 21.7 ± 8.3%) at 1 week, indicating an enhanced osteogenesis due to the peptide incorporation. The results suggested that the incorporation of P‐15 to implant surfaces increased its bioactivity and the effects were notable especially in the early stages of the healing process. © 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 102B: 430–440, 2014.
Pt‐Al2O3 interfaces in cofired ceramics for use in miniaturized neuroprosthetic implants
Authors: Guenther Thomas , Kong Charlie , Lu Hong , Svehla Martin J , Lovell Nigel H , Ruys Andrew , Suaning Gregg J
Published: October 2013

A core element to miniaturized, hermetic encapsulations for neuroprosthetic implants with high numbers of stimulation channels is the creation of electrical feedthroughs. Platinum (Pt) and alumina (Al2O3) are necessary to connect the sealed electronics to external components including electrode arrays that provide a neural interface function, as well as to sources of power or data. Combined with laser micro‐processing, high‐density feedthrough arrays were created with up to 2500 channels per cm2. The chemistry, micro structure, and crystallography of the Pt‐Al2O3 interface created by the cofiring of Pt particles and Al2O3 particulate in binder were studied by transmission electron microscopy (TEM), energy dispersive spectroscopy (EDS) and selective area electron diffraction (SAED) to determine the nature of the Pt‐Al2O3 bond. While Pt‐Al2O3 interfaces only occurred in cases where the different grains were in distinct orientations where the crystal lattices matched, the addition of glass additives allowed for bonding nonmatching orientations by devitrification to form Pt‐glass‐Al2O3 interfaces. The conditions for the formation of both mechanisms were determined, and it was shown that higher order crystal planes than previously described can be matched. Analyzing the lattice matches in detail showed the ability of the material compound to compensate for mismatches by the formation of dislocations, out‐of‐angle matching, lattice distortion, and the existence of semi‐coherent interfaces in case of integer misfit ratios to create domain matching. © 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 102B: 500–507, 2014.
Assessing near infrared optical properties of ceramic orthodontic brackets using cross‐polarization optical coherence tomography
Authors: Isfeld Darren M. , Aparicio Conrado , Jones Robert S.
Published: October 2013

Secondary decay (caries) under ceramic orthodontic brackets remains a significant dental problem and near infrared cross‐polarization optical coherence tomography (CP‐OCT) has the potential to detect underlying demineralization. The purpose of this study was to determine the effect of crystalline structure and chemical composition of ceramic brackets on CP‐OCT imaging. Four ceramic brackets types, which were divided into monocrystalline and polycrystalline, were examined using CP‐OCT. The results of this study demonstrated that the crystallinity of the ceramic brackets affected the 1310 nm CP‐OCT imaging with the greatest attenuation seen in polycrystalline alumina brackets. The alumina polycrystalline bracket materials had significantly higher attenuation and scattering than alumina monocrystalline brackets (p < 0.05, ANOVA, Bonferroni). Additionally, bracket base morphology and composition affected NIR light attenuation. There was considerable attenuation in bracket bases that contained additive zirconium spheres (∼30 µm) and this alteration was significantly greater than the jagged alumina crystallographic alterations found in the other bracket systems (p < 0.05, ANOVA, Bonferroni). Noninvasive, near infrared (NIR) cross‐polarization optical coherence tomography (CP‐OCT) has potential to effectively image through portions of ceramic brackets; however, further investigation into the optical effects of resin integration in the base portion of the brackets is warranted. © 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 102B: 516–523, 2014.
An international survey of pediatric apheresis practice
Authors: Delaney Meghan , Capocelli Kelley E. , Eder Anne F. , Schneiderman Jennifer , Schwartz Joseph , Sloan Steven R. , Wong Edward C.C. , Kim Haewon C.
Published: October 2013

Introduction: Pediatric apheresis (PA) has distinct characteristics compared to adult apheresis, and requires specialized knowledge and experience to perform safely, particularly in low‐weight patients. As evidence‐based medicine advances the field of therapeutic apheresis, increased attention must be paid to pediatric patients with conditions for which apheresis is indicated. Methods: An electronic survey of >5,000 potential participants throughout the world was conducted to ascertain the scope and the current state of practice. Results: The survey elicited 159 responses from 12 countries; 107 of the responses provided sufficient information for analysis. Participants performed an average of 176 PA procedures/year (range: 1–2,000). The types of PA procedures were therapeutic plasma exchange (92% of centers), red cell exchange (86%), leukocyte depletion (87%) and peripheral blood hematopoietic progenitor cell collection (72%). More than 65% of the centers had treated children older than 5 years with PA. Many centers had also performed PA on younger children; 40% have treated patients <12 months of age; 61% had treated patients 1–5 years old. 36% of centers reported that they would perform apheresis regardless of patient weight; 18% used a 5 kg threshold, 11% used 5–10 kg, and 17% used 10 kg as their weight threshold. Conclusion: This report is the largest single survey of centers performing PA. The results provide information about the scope and diversity of PA and identify areas where considerable variability in practice exists. Further exploration of these differences could establish best practices in PA through international research and collaboration. J. Clin. Apheresis 29:120–126, 2014. © 2013 Wiley Periodicals, Inc.
Ab Initio molecular dynamics study of ethylene adsorption onto Si(001) surface: Short‐time fourier transform analysis of structural coordinate autocorrelation function
Authors: Lee Yung Ting , Lin Jyh Shing
Published: October 2013

The reaction dynamics of ethylene adsorption onto the Si(001) surface have been studied by combining density functional theory‐based molecular dynamics simulations with molecular adsorption sampling scheme for investigating all kinds of reaction pathways and corresponding populations. Based on the calculated results, three possible reaction pathways—the indirect adsorption, the direct adsorption, and the repelling reaction—have been found. First, the indirect adsorption, in which the ethylene (C2H4(ads)) forms the π‐bonded C2H4(ads) with the buckled‐down Si atom to adsorb on the Si(001) surface and then turns into the di‐σ‐bonded C2H4(ads), is the major reaction pathway. The short‐time Fourier transform analysis of structural coordinate autocorrelation function is performed to further investigate the evolution of different vibrational modes along this indirect reaction pathway. This analysis illustrates that the Infrared (IR) inactive peak of the CC stretching mode of the π‐bonded C2H4(ads) shifts to the IR inactive peak of the CC stretching mode of di‐σ‐bonded C2H4(ads), which is in a good agreement with the IR inactive peak of the CC stretching mode vanished in the vibrational spectrum at 150 K (Nagao et al., J. Am. Chem. Soc. 2004, 126, 9922). Second, the direct adsorption, in which the di‐σ‐bonded C2H4(ads) is formed directly with the Si intradimer or the Si interdimer on the Si(001) surface, is the less significant reaction pathway. This reaction pathway leads to the CC stretching mode and the CH stretching mode of the di‐σ‐bonded C2H4(ads) appeared in the vibrational spectra at 48 and 150 K, respectively (Nagao et al., J. Am. Chem. Soc. 2004, 126, 9922). Finally, the repelling reaction, in which the C2H4(g) first interacts with the Si dimer and then is repelled by Si atoms, is the least important reaction pathway. Consequently, neither the π‐bonded C2H4(ads) nor the di‐σ‐bonded C2H4(ads) is formed on the Si(001) surface. © 2013 Wiley Periodicals, Inc.
HomoSAR: Bridging comparative protein modeling with quantitative structural activity relationship to design new peptides
Authors: Borkar Mahesh R. , Pissurlenkar Raghuvir R. S. , Coutinho Evans C.
Published: October 2013

Peptides play significant roles in the biological world. To optimize activity for a specific therapeutic target, peptide library synthesis is inevitable; which is a time consuming and expensive. Computational approaches provide a promising way to simply elucidate the structural basis in the design of new peptides. Earlier, we proposed a novel methodology termed HomoSAR to gain insight into the structure activity relationships underlying peptides. Based on an integrated approach, HomoSAR uses the principles of homology modeling in conjunction with the quantitative structural activity relationship formalism to predict and design new peptide sequences with the optimum activity. In the present study, we establish that the HomoSAR methodology can be universally applied to all classes of peptides irrespective of sequence length by studying HomoSAR on three peptide datasets viz., angiotensin‐converting enzyme inhibitory peptides, CAMEL‐s antibiotic peptides, and hAmphiphysin‐1 SH3 domain binding peptides, using a set of descriptors related to the hydrophobic, steric, and electronic properties of the 20 natural amino acids. Models generated for all three datasets have statistically significant correlation coefficients (r2) and predictive

and cross validated coefficient (
). The daintiness of this technique lies in its simplicity and ability to extract all the information contained in the peptides to elucidate the underlying structure activity relationships. The difficulties of correlating both sequence diversity and variation in length of the peptides with their biological activity can be addressed. The study has been able to identify the preferred or detrimental nature of amino acids at specific positions in the peptide sequences. © 2013 Wiley Periodicals, Inc.
Comparative Assessment of Oriented Antibody Immobilization on Surface Plasmon Resonance Biosensing
Authors: Chang Chia‐Chen , Chuang Tsung‐Liang , Wang Da‐Shin , Wang Ching‐Ho , Lin Chii‐Wann
Published: October 2013

Protein A and protein G are extremely useful molecules for the immobilization of antibodies. However, there are limited comparative reports available to evaluate their immobilization performance for use as biosensors. In this study, a comparative analysis was made of approaches that use protein A and protein G for avian leukosis virus detection. The antibody‐protein binding affinities were determined using surface plasmon resonance (SPR) analysis. The immobilization efficiency was obtained by calculating the number of the protein molecular binding sites. The positive influence of sensor response on antigen detection indicates that the amount of immobilized antibody plays a major role in the extent of immobilization. Moreover, the biosensors constructed using both proteins were found to be regenerative. The SPR results from this study suggest that the surfaces of protein G provide a better equilibrium constant and binding efficacy for immobilized antibodies, resulting in enhanced antigen detection.
RGS2 Regulates Urotensin II‐Induced Intracellular Ca2+ Elevation and Contraction in Glomerular Mesangial Cells
Authors: Adebiyi Adebowale
Published: October 2013

Urotensin II (UII), a vasoactive peptide modulates renal hemodynamics. However, the physiological functions of UII in glomerular cells are unclear. In particular, whether UII alters mesangial tone remains largely unknown. The present study investigates the physiological effects of UII on glomerular mesangial cells (GMCs). This study also tested the hypothesis that the regulator of G‐protein signaling (RGS) controls UII receptor (UTR) activity in GMCs. RT‐PCR, Western immunoblotting, and immunofluorescence revealed UTR expression in cultured murine GMCs. Mouse UII (mUII) stimulated Ca2+ release from intracellular stores and activated store‐operated Ca2+ entry (SOCE) in the cells. mUII also caused a reduction in planar GMC surface area. mUII‐induced [Ca2+]i elevation and contraction were attenuated by SB 657510, a UTR antagonist, araguspongin B, an inositol 1,4,5‐trisphosphate receptor antagonist, thapsigargin, a sarco/endoplasmic reticulum Ca2+‐ATPase inhibitor, and La3+, a store‐operated Ca2+ channel blocker, but not nimodipine, an L‐type Ca2+ channel blocker. In situ proximity ligation assay indicated molecular proximity between endogenous RGS2 and UTR in the cells. Treatment of GMCs with mUII elevated plasma membrane expression of RGS2 by ∼2‐fold. mUII also increased the interaction between RGS2 and UTR in the cells. siRNA‐mediated knockdown of RGS2 in murine GMCs increased mUII‐induced [Ca2+]i elevation and contraction by ∼35 and 31%, respectively. These findings indicate that mUII‐induced SOCE results in murine GMC contraction. These data also suggest that UTR activation stimulates RGS2 recruitment to GMC plasma membrane as a negative feedback mechanism to regulate UTR signaling. J. Cell. Physiol. 229: 502–511, 2014. © 2013 Wiley Periodicals, Inc.
Taste and odorant receptors of the coelacanth—A gene repertoire in transition
Authors: Picone Barbara , Hesse Uljana , Panji Sumir , Van Heusden Peter , Jonas Mario , Christoffels Alan
Published: October 2013

G‐protein coupled chemosensory receptors (GPCR‐CRs) aid in the perception of odors and tastes in vertebrates. So far, six GPCR‐CR families have been identified that are conserved in most vertebrate species. Phylogenetic analyses indicate differing evolutionary dynamics between teleost fish and tetrapods. The coelacanth Latimeria chalumnae belongs to the lobe‐finned fishes, which represent a phylogenetic link between these two groups. We searched the genome of L. chalumnae for GPCR‐CRs and found that coelacanth taste receptors are more similar to those in tetrapods than in teleost fish: two coelacanth T1R2s co‐segregate with the tetrapod T1R2s that recognize sweet substances, and our phylogenetic analyses indicate that the teleost T1R2s are closer related to T1R1s (umami taste receptors) than to tetrapod T1R2s. Furthermore, coelacanths are the first fish with a large repertoire of bitter taste receptors (58 T2Rs). Considering current knowledge on feeding habits of coelacanths the question arises if perception of bitter taste is the only function of these receptors. Similar to teleost fish, coelacanths have a variety of olfactory receptors (ORs) necessary for perception of water‐soluble substances. However, they also have seven genes in the two tetrapod OR subfamilies predicted to recognize airborne molecules. The two coelacanth vomeronasal receptor families are larger than those in teleost fish, and similar to tetrapods and form V1R and V2R monophyletic clades. This may point to an advanced development of the vomeronasal organ as reported for lungfish. Our results show that the intermediate position of Latimeria in the phylogeny is reflected in its GPCR‐CR repertoire. J. Exp. Zool. (Mol. Dev. Evol.) 322B: 403–414, 2014. © 2013 Wiley Periodicals, Inc.
Modeling radiation belt electron dynamics during GEM challenge intervals with the DREAM3D diffusion model
Authors: Tu Weichao , Cunningham G. S. , Chen Y. , Henderson M. G. , Camporeale E. , Reeves G. D.
Published: October 2013

As a response to the Geospace Environment Modeling (GEM) “Global Radiation Belt Modeling Challenge,” a 3D diffusion model is used to simulate the radiation belt electron dynamics during two intervals of the Combined Release and Radiation Effects Satellite (CRRES) mission, 15 August to 15 October 1990 and 1 February to 31 July 1991. The 3D diffusion model, developed as part of the Dynamic Radiation Environment Assimilation Model (DREAM) project, includes radial, pitch angle, and momentum diffusion and mixed pitch angle‐momentum diffusion, which are driven by dynamic wave databases from the statistical CRRES wave data, including plasmaspheric hiss, lower‐band, and upper‐band chorus. By comparing the DREAM3D model outputs to the CRRES electron phase space density (PSD) data, we find that, with a data‐driven boundary condition at Lmax = 5.5, the electron enhancements can generally be explained by radial diffusion, though additional local heating from chorus waves is required. Because the PSD reductions are included in the boundary condition at Lmax = 5.5, our model captures the fast electron dropouts over a large L range, producing better model performance compared to previous published results. Plasmaspheric hiss produces electron losses inside the plasmasphere, but the model still sometimes overestimates the PSD there. Test simulations using reduced radial diffusion coefficients or increased pitch angle diffusion coefficients inside the plasmasphere suggest that better wave models and more realistic radial diffusion coefficients, both inside and outside the plasmasphere, are needed to improve the model performance. Statistically, the results show that, with the data‐driven outer boundary condition, including radial diffusion and plasmaspheric hiss is sufficient to model the electrons during geomagnetically quiet times, but to best capture the radiation belt variations during active times, pitch angle and momentum diffusion from chorus waves are required.
Longitudinal variations of positive dayside ionospheric storms related to recurrent geomagnetic storms
Authors: Dmitriev A. V. , Huang C.‐M. , Brahmanandam P. S. , Chang L. C. , Chen K.‐T. , Tsai L.‐C.
Published: October 2013

We have performed an analysis of case events and statistics of positive ionospheric storms in the dayside region of the equatorial ionization anomaly during recurrent geomagnetic storms (RGSs), which dominate in geomagnetic and ionospheric conditions on the declining phase of solar activity in 2004 to 2008. It is shown that total electron content (TEC) has a tendency to minimize before the beginning of RGSs and to peak 3 to 4 days after, i.e., on the RGS recovery phase produced by high‐intensity long‐duration continuous auroral activity. The maximum of TEC coincides with the maximum of solar wind velocity within high‐speed solar wind streams. An analysis of electron content vertical profiles, derived from two independent methods using ionosondes and Constellation Observing System for Meteorology, Ionosphere, and Climate /Formosa Satellite mission‐3 radio occultation, showed that in the maximum of an ionospheric storm on 28 March 2008, the F2 layer thickens, NmF2 increases by ~50%, and hmF2 elevates by a few tens of kilometers. The response of positive ionospheric storms to solar, heliospheric, and geomagnetic drivers reveals a prominent longitudinal asymmetry. In the longitudinal range from −90° to 90°, the solar illumination plays a major role, and in the range from 90° to −120°, the influence of heliospheric and geomagnetic drivers becomes significant. The highest correlations of the TEC enhancements with the heliospheric and geomagnetic drivers were found during December–February (r increased from ~0.3 to ~0.5). We speculate that the dynamics controlling this might result from an effect of solar zenith angle, storm time effects of thermospheric ΣO/N2 enhancement, and penetrating electric fields of interplanetary and magnetospheric origin.
Application of OMI, SCIAMACHY, and GOME‐2 satellite SO2 retrievals for detection of large emission sources
Authors: Fioletov V. E. , McLinden C. A. , Krotkov N. , Yang K. , Loyola D. G. , Valks P. , Theys N. , Van Roozendael M. , Nowlan C. R. , Chance K. , Liu X. , Lee C. , Martin R. V.
Published: October 2013

Retrievals of sulfur dioxide (SO2) from space‐based spectrometers are in a relatively early stage of development. Factors such as interference between ozone and SO2 in the retrieval algorithms often lead to errors in the retrieved values. Measurements from the Ozone Monitoring Instrument (OMI), Scanning Imaging Absorption Spectrometer for Atmospheric Chartography (SCIAMACHY), and Global Ozone Monitoring Experiment‐2 (GOME‐2) satellite sensors, averaged over a period of several years, were used to identify locations with elevated SO2 values and estimate their emission levels. About 30 such locations, detectable by all three sensors and linked to volcanic and anthropogenic sources, were found after applying low and high spatial frequency filtration designed to reduce noise and bias and to enhance weak signals to SO2 data from each instrument. Quantitatively, the mean amount of SO2 in the vicinity of the sources, estimated from the three instruments, is in general agreement. However, its better spatial resolution makes it possible for OMI to detect smaller sources and with additional detail as compared to the other two instruments. Over some regions of China, SCIAMACHY and GOME‐2 data show mean SO2 values that are almost 1.5 times higher than those from OMI, but the suggested spatial filtration technique largely reconciles these differences.
Estimating the radiative forcing of carbonaceous aerosols over California based on satellite and ground observations
Authors: Xu Yangyang , Bahadur Ranjit , Zhao Chun , Ruby Leung L.
Published: October 2013

Carbonaceous aerosols have the potential to impact climate directly through absorption of incoming solar radiation and indirectly by affecting cloud and precipitation. Recent modeling studies have made great efforts to simulate both the spatial and temporal distributions of carbonaceous aerosol's optical properties and radiative forcing. This study makes the first observationally constrained assessment of the direct radiative forcing of carbonaceous aerosols over California. By exploiting multiple observations (including ground sites and satellites), we constructed the distribution of aerosol optical depths and aerosol absorption optical depths (AAOD) over California for a 10 year period (2000–2010). We partitioned the total solar absorption into individual contributions from elemental carbon (EC), organic carbon (OC), and dust aerosols, using a newly developed scheme. Our results show that AAOD due to carbonaceous aerosols (EC and OC) at 440 nm was 50%–200% larger than natural dust, with EC contributing the bulk (70%–90%). Observationally constrained EC absorption agrees reasonably well with estimates from global and regional chemical transport models, but the models underestimate the OC AAOD by at least 50%. We estimated that the top of the atmosphere (TOA) forcing from carbonaceous aerosols was 0.7 W/m2 and the TOA forcing due to OC was close to zero. The atmospheric heating of carbonaceous aerosol was 2.2–2.9 W/m2, of which EC contributed about 80–90%. We estimated the atmospheric heating of OC at 0.1–0.4 W/m2, larger than model simulations. EC reduction over the last two decades may have caused a surface brightening of 1.5–3.5 W/m2.
Characteristics of the subtropical tropopause region based on long‐term highly resolved sonde records over Tenerife
Authors: Rodriguez‐Franco Juan J. , Cuevas Emilio
Published: October 2013

This study examines the structure of the subtropical tropopause region over Tenerife (the Canary Islands, Spain; 28°N, 16°W) based on a 20 year (1992–2011) ozonesonde data and European Center for Medium‐Range Weather Forecasts ERA‐Interim potential vorticity (PV) and zonal wind speed reanalysis. High‐resolution vertical profiles allowed a detailed description of the subtropical tropopause break and the associated subtropical jet stream (STJ), where models fail to properly simulate the upper troposphere–lower stratosphere (UTLS). The subtropical UTLS is revealed as a complex atmospheric region with a thickness ∼8 km, which is examined through the analysis and evaluation of four different tropopause definitions: thermal (TT), cold point, ozone (OT), and dynamical (DT) tropopauses. A novel method to determine the DT based on the vertical gradient of Lait's modified PV is presented and the concept of a second DT has been introduced for the first time. Monthly climatologies of tropopause height and potential temperature are calculated for double and single tropopause events. The 14.3 km height level is used to differentiate between tropical and extratropical UTLS regimes, intimately linked to the position of the STJ. There is fairly good consistency between all the defined tropopauses under the double tropopause scheme, except in spring, when the OT is observed at lower levels due to frequent baroclinic instabilities in the upper troposphere. As concerns to single tropopause events, the same pattern is found from April to June, reflecting the influence of analogous processes during these months. In winter, altitude differences between OT, DT, and TT resulted from poleward STJ excursions forced by blocking systems over the North Atlantic. Analysis of the tropopause inversion layer showed distinctive features for tropical and midlatitude tropopauses.
Modeling of observed mineral dust aerosols in the arctic and the impact on winter season low‐level clouds
Authors: Fan Song‐Miao
Published: October 2013

Mineral dust aerosol is the main ice nucleus (IN) in the Arctic. Observed dust concentrations at Alert, Canada, are lowest in winter and summer and highest in spring and autumn. In this study, we simulate transport and deposition of dust in a global chemical transport model. The model predicts the spring maximum caused by natural dust from desert sources in Asia and Sahara but underestimates the observations in autumn. Both natural and pollution sources contribute to the wintertime dust burden, as suggested by previous measurements of elemental compositions. Cloud parcel model simulations were carried out to study the impact of dust aerosol on the formation of mixed‐phase and ice clouds in the Arctic lower troposphere. The liquid water path of low‐level cloud is most sensitive to dust aerosol concentration from winter to early spring when air temperature is at its lowest in the annual cycle. The global and parcel models together suggest that low concentrations and acid coating of dust particles are favorable conditions for occurrence of mixed‐phase clouds and that anthropogenic pollution can cause significant perturbations to Arctic IN and clouds in winter.
Evaluation of CMIP5 20th century climate simulations for the Pacific Northwest USA
Authors: Rupp David E. , Abatzoglou John T. , Hegewisch Katherine C. , Mote Philip W.
Published: October 2013

Monthly temperature and precipitation data from 41 global climate models (GCMs) of the Coupled Model Intercomparison Project Phase 5 (CMIP5) were compared to observations for the 20th century, with a focus on the United States Pacific Northwest (PNW) and surrounding region. A suite of statistics, or metrics, was calculated, that included correlation and variance of mean seasonal spatial patterns, amplitude of seasonal cycle, diurnal temperature range, annual‐ to decadal‐scale variance, long‐term persistence, and regional teleconnections to El Niño Southern Oscillation (ENSO). Performance, or credibility, was assessed based on the GCMs' abilities to reproduce the observed metrics. GCMs were ranked in their credibility using two methods. The first simply treated all metrics equally. The second method considered two properties of the metrics: (1) redundancy of information (dependence) among metrics, and (2) confidence in the reliability of an individual metric for accurately ranking models. Confidence was related to how robust the estimate of the metric was to ensemble size, given that for most of the models only a small number of ensemble members (i.e., realizations of the 20th century) were available. A cursory comparison with 24 CMIP3 models revealed few differences between the two generations of models with respect to the statistics analyzed.
Gravity wave activity in the troposphere and lower stratosphere: An observational study of seasonal and interannual variations
Authors: Wu Yongfu , Yuan Wei , Xu Jiyao
Published: October 2013

An 11 year (1998‐2008) temperature and wind data set obtained over Annette Island (55.03°N, 131.57°W) is used to examine gravity wave activity and their seasonal and interannual variations in gravity wave activity. Vertical wave number spectra of normalized temperature and wind fluctuations are calculated and are compared with the predictions of gravity wave saturation models. Results indicate that there are serious discrepancies between our measurements and earlier observational results at present stage of study of vertical wave number spectra. The correlation coefficients between tropospheric and stratospheric temperature spectral parameters are very small, suggesting that the result is in agreement with previous studies. Time series of total wave energy reveal clear seasonal and interannual variations. Maximum wave energy amplitudes occur near winter of each year in the troposphere and near summer of each year in the stratosphere. Specifically, the maximum wave energy amplitudes in the troposphere show a close correspondence with the maximum occurrence rate of dynamical instability. In addition, the maximum wave energy amplitudes in the stratosphere also show a close correspondence with the maximum occurrence rate of convective instability.
Predictability of soil moisture and streamflow on subseasonal timescales: A case study
Authors: Orth Rene , Seneviratne Sonia I.
Published: October 2013

Hydrological forecasts constitute an important tool in water resource management, especially in the case of impending extreme events. This study investigates the potential predictability of soil moisture and streamflow in Switzerland using a conceptual model including a simple water balance representation and a snow module. Our results show that simulated soil moisture and streamflow are more predictable (as indicated by significantly improved performance compared to climatology) until lead times of approximately 1 week and 2–3 days, respectively, when using initial soil moisture information and climatological atmospheric forcing. Using also initial snow information and seasonal weather forecasts as forcing, the predictable lead time doubles in case of soil moisture and triples for streamflow. The skill contributions of the additional information vary with altitude; at low altitudes the precipitation forecast is most important, whereas in mountainous areas the temperature forecast and the initial snow information are the most valuable contributors. We find furthermore that the soil moisture and streamflow forecast skills increase with increasing initial soil moisture anomalies. Comparing the respective value of realistic initial conditions and state‐of‐the‐art forcing forecasts, we show that the former are generally more important for soil moisture forecasts, whereas the latter are more valuable for streamflow forecasts. To relate the derived predictabilities to respective soil moisture and streamflow memories investigated in other publications, we additionally illustrate the similarity between the concepts of memory and predictability as measures of persistence in the last part of this study.
An evaluation of the role of NKG2C+ natural killer cells in protection from cytomegalovirus DNAemia early following allogeneic stem cell transplantation
Authors: Muñoz‐Cobo Beatriz , Giménez Estela , Solano Carlos , de la Cámara Rafael , Nieto José , López Javier , Amat Paula , Garcia‐Noblejas Ana , Navarro David
Published: October 2013

The role of natural killer (NK) cells in affording protection against human cytomegalovirus (CMV) in allogeneic stem cell transplant recipients is largely unknown. The current study was aimed at determining whether NKG2C+ NK cells confer protection from CMV DNAemia early following transplantation in patients lacking mono and polyfunctional CMV pp65 and IE‐1‐specific CD4+ and CD8+ T‐cell responses, as measured by flow cytometry for intracellular cytokine staining. Fourteen out of the 36 patients included in this study developed CMV DNAemia between days +30 and +60 after transplant. Three patients did so after day +60. Peripheral blood levels of CD56brightCD16−/low and CD56dimCD16+ NKG2C+ NK cells measured at day +30 and at day +60 in patients who had or had not subsequent CMV DNAemia did not differ significantly. In addition, no significant correlation was found between CD56brightCD16−/low (σ = −0.229; P = 0.39) and CD56dimCD16+ (σ = −0.285; P = 0.28) NKG2C+ NK‐cell levels and initial plasma CMV DNA loads. In summary, the data presented do not support a direct implication of NKG2C+ NK cells in preventing the development of CMV DNAemia or modulating the magnitude of CMV replication at early stages during episodes of CMV DNAemia in allogeneic stem cell transplant patients with unreconstituted CMV‐specific T‐cell responses. J. Med. Virol. 86:806–811, 2014. © 2013 Wiley Periodicals, Inc.
Detection and molecular characterization of diarrhea causing viruses in single and mixed infections in children: A comparative study between Bangladesh and Turkey
Authors: Mitui Marcelo Takahiro , Bozdayi Gulendam , Ahmed Selim , Matsumoto Takashi , Nishizono Akira , Ahmed Kamruddin
Published: October 2013

The incidence and mortality caused by diarrhea differ among countries. The prevalence of different enteric viruses, their molecular characteristics, and infections with multiple viruses might affect the disease incidence and mortality caused by diarrhea. The objective of this study was to determine the distribution and molecular characteristics of enteric viruses in children with diarrhea in Turkey and Bangladesh. A total of 288 stool samples that were negative for group A rotavirus were collected from children aged <5 years with acute diarrhea who presented to hospitals in Turkey and Bangladesh. The samples were screened for human bocavirus (HBoV), astrovirus (HAstV), norovirus (NoV), and adenovirus (AdV). Phylogenetic analyses of the targeted virus genes were performed. In Turkey, viruses were detected in 87/150 samples (58%), which included 69 (79.3%) with single viruses and 18 (20.7%) with multiple viruses. AdV was the most common virus, followed by HBoV. In Bangladesh, viruses were detected in 123/138 samples (89.1%), which included 29 (23.6%) with single viruses and 94 (76.4%) with multiple viruses. NoV GII was the most common, followed by AdV. The dominant genotypes among the virus species were HBoV 2A, HAstV 1, NoV GI type 1, and AdV 40. For NoV GII, the Hunter variant of genotype 4 in Turkey and genotype 17 in Bangladesh were the most common among the sequenced strains. It was concluded that the distribution of the viruses associated with diarrhea in Turkish and Bangladeshi children was different. Enteric viruses and mixed infections were more prevalent in Bangladesh than in Turkey. J. Med. Virol. 86:1159–1168, 2014. © 2013 Wiley Periodicals, Inc.
Prevalence of human papillomaviruses in patients with head and neck squamous cell carcinoma in Lithuania and Belarus
Authors: Zivile Gudleviciene , Janina Didziapetriene , Irina Mackeviciene , Saulius Cicenas , Raisa Smolyakova , Aliaksandr Zhukavetc
Published: October 2013

Overall, head and neck sqamous cell carcinoma accounts for more than 550,000 cases annually worldwide. It is well known that human papillomavirus (HPV) is the main risk factor for cervical cancer development. As the incidence and the mortality of cervical cancer are closely related to the HPV prevalence, we hypothesized that there is the same association between HPV prevalence and head and neck squamous cell carcinoma. Therefore we performed the study aiming to compare the level of HPV infection and HPV type distribution between two groups of Lithuanian and Belarusian patients with head and neck sqamous cell carcinoma. One hundred ninety head and neck sqamous cell carcinoma patients were included in the study, 75 from Lithuania and 115 from Belarus. PCR was used for HPV detection and typing. The distribution of HPV infection among head and neck sqamous cell carcinoma patients was similar in the Lithuanian (20.0%) and Belarusian (18.3%) patient groups, however differences were found in the distribution of HPV types. J. Med. Virol. 86:531–535, 2014. © 2013 Wiley Periodicals, Inc.
Effect of glial cell line‐derived neurotrophic factor on behavior and key members of the brain serotonin system in mouse strains genetically predisposed to behavioral disorders
Authors: Naumenko Vladimir S. , Bazovkina Daria V. , Semenova Alina A. , Tsybko Anton S. , Il'chibaeva Tatyana V. , Kondaurova Elena M. , Popova Nina K.
Published: October 2013

The effect of glial cell line‐derived neurotrophic factor (GDNF) on behavior and on the serotonin (5‐HT) system of a mouse strain predisposed to depressive‐like behavior, ASC/Icg (Antidepressant Sensitive Cataleptics), in comparison with the parental “nondepressive” CBA/Lac mice was studied. Within 7 days after acute administration, GDNF (800 ng, i.c.v.) decreased cataleptic immobility but increased depressive‐like behavioral traits in both investigated mouse strains and produced anxiolytic effects in ASC mice. The expression of the gene encoding the key enzyme for 5‐HT biosynthesis in the brain, tryptophan hydroxylase‐2 (Tph‐2), and 5‐HT1A receptor gene in the midbrain as well as 5‐HT2A receptor gene in the frontal cortex were increased in GDNF‐treated ASC mice. At the same time, GDNF decreased 5‐HT1A and 5‐HT2A receptor gene expression in the hippocampus of ASC mice. GDNF failed to change Tph2, 5‐HT1A, or 5‐HT2A receptor mRNA levels in CBA mice as well as 5‐HT transporter gene expression and 5‐HT1A and 5‐HT2A receptor functional activity in both investigated mouse strains. The results show 1) a GDNF‐induced increase in the expression of key genes of the brain 5‐HT system, Tph2, 5‐HT1A, and 5‐HT2A receptors, and 2) significant genotype‐dependent differences in the 5‐HT system response to GDNF treatment. The data suggest that genetically defined cross‐talk between neurotrophic factors and the brain 5‐HT system underlies the variability in behavioral response to GDNF. © 2013 Wiley Periodicals, Inc.
Chemical composition and antioxidant properties of Laurus nobilis L. and Myrtus communis L. essential oils from Morocco and evaluation of their antimicrobial activity acting alone or in combined processes for food preservation
Authors: Cherrat Lamia , Espina Laura , Bakkali Mohammed , García‐Gonzalo Diego , Pagán Rafael , Laglaoui Amin
Published: October 2013

BACKGROUND

This study describes the antioxidant and antimicrobial activity of Laurus nobilis L. and Myrtus communis L. essential oils (EOs). This is the first report of the synergistic antimicrobial effect of these EOs in combination with physical food preservation treatments.

RESULTS

EOs obtained by steam distillation from aerial parts of Laurus nobilis and Myrtus communis were analysed by using gas chromatography–mass spectrometry. The main compounds were 1,8‐cineole and 2‐carene (L. nobilis EO); and myrtenyl acetate, 1,8‐cineole and α‐pinene (M. communis EO). L. nobilis EO showed higher antioxidant activity than M. communis EO in three complementary antioxidant tests. Although antimicrobial activity tests demonstrated the effectiveness of L. nobilis EO and the lack of bactericidal effect of M. communis EO, synergistic lethal effects were observed when combining each EO (0.2 µL mL−1) with mild heat (54°C for 10 min) or high hydrostatic pressure (175–400 MPa for 20 min). In contrast, combination of EOs with pulsed electric fields (30 kV cm−1 for 25 pulses) showed no additional effects.

CONCLUSION

This study shows the great potential of these EOs in combined treatments with mild heat and high hydrostatic pressure to obtain a higher inactivation of foodborne pathogens, which might help in the design of safe processes applied at low intensity. © 2013 Society of Chemical Industry