bluuebunny/crossref_metadata_2025 huggingface dataset:
Alcohol Withdrawal and Brain Injuries: Beyond Classical Mechanisms
Authors: Jung Marianna E. , Metzger Daniel B.
Published: July 2010

Unmanaged sudden withdrawal from the excessive consumption of alcohol (ethanol) adversely alters neuronal integrity in vulnerable brain regions such as the cerebellum, hippocampus, or cortex. In addition to well known hyperexcitatory neurotransmissions, ethanol withdrawal (EW) provokes the intense generation of reactive oxygen species (ROS) and the activation of stress-responding protein kinases, which are the focus of this review article. EW also inflicts mitochondrial membranes/membrane potential, perturbs redox balance, and suppresses mitochondrial enzymes, all of which impair a fundamental function of mitochondria. Moreover, EW acts as an age-provoking stressor. The vulnerable age to EW stress is not necessarily the oldest age and varies depending upon the target molecule of EW. A major female sex steroid, 17β-estradiol (E2), interferes with the EW-induced alteration of oxidative signaling pathways and thereby protects neurons, mitochondria, and behaviors. The current review attempts to provide integrated information at the levels of oxidative signaling mechanisms by which EW provokes brain injuries and E2 protects against it.
Artesunate: The Best Drug in the Treatment of Severe and Complicated Malaria
Authors: Li Qigui , Weina Peter
Published: July 2010

This review summarizes progress in treating severe and complicated malaria, which are global problems, claiming at least one million lives annually, and have been accompanied by advances in our understanding of the pathogenesis of severe malaria complications. New drugs such as intravenous artesunate (AS) and intramuscular artemether (AM) are improving outcomes and decreasing malaria deaths. Trials comparing AM to the traditional parenteral drug, quinine, have not demonstrated however convincing evidence of a mortality advantage for AM. The South East Asian Quinine Artesunate Malaria Trials (SEAQUAMAT), a multicenter, randomized, open-label study comparing AS with quinine showed that parenteral AS was shown to be associated with a 35% reduction in the risk of mortality compare to quinine, and is now the recommended treatment by the WHO for severe and complicated malaria in low-transmission areas and in the second and third trimesters of pregnancy, with almost all the benefit reported in those with high parasite counts. Artesunate is a semisynthetic derivative of artemisinin whose water solubility facilitates absorption and provides an advantage over other artemisinins because it can be formulated as oral, rectal, intramuscular, and intravenous preparations. Artesunate is rapidly hydrolyzed to dihydroartemisinin, which is the most active schizonticidal metabolite. Injectable AS results in a more rapid systemic availability of AS compared with intramuscular AM. This pharmacokinetic advantage may provide a clinical advantage in the treatments of severe and complicated malaria.
Microwave Radiometer Resolution Optimization Using Variable Observation Times
Authors: Camps Adriano , Tarongí Jose Miguel
Published: July 2010

This manuscript first revises the performance of total power, Dicke-type and noise-injection microwave radiometers. Equations for the radiometric resolution are revised or derived, and their performance in terms of the radiometric resolution improvement with respect to the ideal total power radiometer resolution is evaluated. It is then shown that the radiometric resolution of noise-injection radiometers can be optimized by adjusting dynamically the integration times devoted to the three measurements: antenna, antenna plus noise, and reference load. Numerical results are then presented to illustrate the dependence of the radiometric resolution with different instrument parameters. Experimental results are finally presented to corroborate the predicted performance. It is also shown that in many cases of interest these integration times can be set to a constant value with little degradation with respect to the optimum case, but better than the case in which the total integration time is divided in three equal subintervals.
Fluorescent Chemosensors for Toxic Organophosphorus Pesticides: A Review
Authors: Obare Sherine O. , De Chandrima , Guo Wen , Haywood Tajay L. , Samuels Tova A. , Adams Clara P. , Masika Noah O. , Murray Desmond H. , Anderson Ginger A. , Campbell Keith , Fletcher Kenneth
Published: July 2010

Many organophosphorus (OP) based compounds are highly toxic and powerful inhibitors of cholinesterases that generate serious environmental and human health concerns. Organothiophosphates with a thiophosphoryl (P=S) functional group constitute a broad class of these widely used pesticides. They are related to the more reactive phosphoryl (P=O) organophosphates, which include very lethal nerve agents and chemical warfare agents, such as, VX, Soman and Sarin. Unfortunately, widespread and frequent commercial use of OP-based compounds in agricultural lands has resulted in their presence as residues in crops, livestock, and poultry products and also led to their migration into aquifers. Thus, the design of new sensors with improved analyte selectivity and sensitivity is of paramount importance in this area. Herein, we review recent advances in the development of fluorescent chemosensors for toxic OP pesticides and related compounds. We also discuss challenges and progress towards the design of future chemosensors with dual modes for signal transduction.
Islet Isolation from Juvenile Porcine Pancreas after 24-h Hypothermic Machine Perfusion Preservation
Authors: Taylor Michael J. , Baicu Simona , Greene Elizabeth , Vazquez Alma , Brassil John
Published: July 2010

Pancreas procurement for islet isolation and transplantation is limited by concerns for the detrimental effects of postmortem ischemia. Hypothermic machine perfusion (HMP) preservation technology has had a major impact in circumventing ischemic injury in clinical kidney transplantation and is applied here to the preservation and procurement of viable islets after hypothermic perfusion preservation of porcine pancreata because pigs are now considered the donor species of choice for xenogeneic islet transplantation. Pancreases were surgically removed from young (<6 months) domestic Yorkshire pigs (25–32 kg), either before or after 30 min of warm ischemia time (WIT), and cannulated for perfusion. Each pancreas was assigned to one of six preservation treatment groups: fresh controls—processed immediately (cold ischemia <1 h) (G1, n = 7); static cold storage—flushed with cold UW-Viaspan and stored in UW-Viaspan at 2–4°C for 24 h with no prior WIT (G2, n = 9); HMP perfused on a LifePort® machine at 4–6°C and low pressure (10 mmHg) for 24 h with either KPS1 solution (G3, n = 7) or Unisol-UHK (G4, n = 7). Additional treatment groups to evaluate the effects of prior warm ischemia examined islet isolation after 30 min WIT in situ without (G5, n = 6) or with subsequent 24-h HMP with KPS1 (G6, n = 7). The pancreas was intraductally distended with Liberase PI enzyme and normothermically digested. The isolated islets were purified by a continuous density-gradient centrifugation. Perfusion-induced glandular edema was G3 = 138 ± 19%, G4 = 160 ± 16%, and G6 = 127 ± 22%. Islet yield (IEQ/g of pancreas) varied between the groups: G1 = 1,425 ± 610, G2 = 1,002 ± 262, G3 = 2,242 ± 449 ( p < 0.05 vs. G2), G4 = 1,901 ± 420 ( p < 0.05 vs. G2), G5 = 1,756 ± 329, and G6 = 1,396 ± 243. Islet stimulation indices were equivalent between the groups and similar to controls (G1). Insulin content (ng/IE) was different between the treatment groups with the highest insulin content in islets harvested from HMP pancreata. Dithizone staining for islets consistently showed more uniform digestion of the perfused organs, with greater separation of the tissue, less entrapped islets, and higher islet yield and purity. The salutary effects of HMP for 24 h were also manifest after 30-min prior warm ischemia. We conclude that 24 h of HMP is well tolerated, leading to moderate edema but no loss of function of the harvested islets. The edema appears to aid in enzymatic digestion, producing a greater yield and purity of islets compared with pancreas subjected to 24 h of static cold storage.
Transplantation of Cultured Autologous Melanocytes: Hope or Danger?
Authors: Czajkowski Rafal , Pokrywczynska Marta , Placek Waldemar , Zegarska Barbara , Tadrowski Tadeusz , Drewa Tomasz
Published: July 2010

Cultured human melanocytes are increasingly being used in the treatment of vitiligo. The growth media contain various types of mitogenic factors, both recombinant human (e.g., rhbFGF and rhSCF) and synthetic (e.g., TPA). High concentrations of mitogenic factors accelerate the cell cycle, and consequently may increase the risk of carcinogenesis of transplanted cells. Mutations of genes of the RAS/RAF/MEK/ERK signaling pathway are very often found in the early stages of the development of melanoma. TPA is considered to be an oncogenic factor, but so far there is no evidence to show that it is responsible for damage to the genetic material of cultured melanocytes. The aim of our study was to assess the risk of the development of mutations in selected genes of the RAS/RAF/MEK/ERK signaling pathway during the culturing of melanocytes in various growth media. Based on the results obtained, it can be concluded that TPA and high concentrations of other growth factors intensify the proliferation of melanocytes, without the risk of damage to the HRAS (exon 1 and 2), KRAS (exon 1 and 2), NRAS (exon 1 and 2), and BRAF (exon 11 and 15) genes. In order to assess the total safety of the transplantation of cultured melanocytes, it is necessary to carry out further studies on other signaling pathways as well as carry out biological tests on an animal model.
Chromo- and fluorophoric water-soluble polymers and silica particles by nucleophilic substitution reaction of poly(vinyl amine)
Authors: Hofmann Katja , Kahle Ingolf , Simon Frank , Spange Stefan
Published: July 2010

Novel chromophoric and fluorescent carbonitrile-functionalized poly(vinyl amine) (PVAm) and PVAm/silica particles were synthesized by means of nucleophilic aromatic substitution of 8-oxo-8H-acenaphtho[1,2-b]pyrrol-9-carbonitrile (1) with PVAm in water. The water solubility of 1 has been mediated by 2,6-O-β-dimethylcyclodextrin or by pre-adsorption onto silica particles. Furthermore, 1 was converted with isopropylamine into the model compound 1-M. All new compounds were characterized by NMR, FTIR, UV–vis and fluorescence spectroscopy. The solvent-dependent UV–vis absorption and fluorescence emission band positions of the model compound and the carbonitrile-functionalized PVAm were studied and interpreted using the empirical Kamlet–Taft solvent parameters π* (dipolarity/polarizability), α (hydrogen-bond donating capacity) and β (hydrogen-accepting ability) in terms of the linear solvation energy relationship (LSER). The solvent-independent regression coefficients a, b and s were determined using multiple linear correlation analysis. It is shown, that the chains of the polymer have a significant influence on the solvatochromic behavior of 1-P. The structure of the carbonitrile 1-Si bound to polymer-modified silica particles was studied by means of X-ray photoelectron spectroscopy (XPS) and Brunauer–Emmett–Teller (BET) measurements. Fluorescent silica particles were obtained as shown by fluorescence spectroscopy with a diffuse reflectance technique.
MATHEMATICAL MODELING OF DATA TRANSMISSION SYSTEM IN COMMUNICATION NETWORKS/DUOMENŲ PERDAVIMO RYŠIO TINKLAIS MATEMATINIS MODELIAVIMAS
Authors: Zijuan Wu
Published: July 2010

Probability failure in operation as well as error probability at fixed frequency band, number of users, and data transmission speed have been analyzed.

Santrauka

Išnagrinėta aptarnavimo atmetimo tikimybė bei klaidų tikimybė fiksuotų dažnių juostose, abonentų skaičiaus ir informacijos perdavimo greičio nustatyme.
DYNAMICS OF PASSENGER TRAFFIC FLOW AT VILNIUS, RIGA, TALLINN AND KRAKOW AIRPORTS
Authors: Christauskas Julius , Stanaitis Jurgis
Published: July 2010

The article contains the results of an analysis of the dynamics of passenger traffic flow at Vilnius, Riga, Tallinn and Krakow airports during a period of ten years. The variation in the number of take-off and landing operations in the airports is analyzed as well. The current situation and prospects for the technical development of the airports are presented. Subjective and objective reasons related to insufficient activities at Vilnius Airport are presented. Possibilities for changing the location of the main airport in Lithuania are mentioned.
Carmen de Burgos y Ramón Gómez de la Serna
Authors: Ubach Medina Antonio
Published: July 2010

Carmen de Burgos, proveniente de la sureña provincia de Almería, llega a Madrid a principios del s. XX, decidida a mantener su independencia tras un desdichado matrimonio y a ganarse la vida escribiendo, apoyando una serie de causas sociales, su idea de la literatura y los jóvenes valores. Ramón Gómez de la Serna, veinte años más joven que ella, la conoce en 1908, cuando comienza su carrera literaria. Carmen encarna el ideal de mujer que describe en su conferencia sobre “La nueva literatura”. Durante veinte años comparten vida, viajes y escritura en una fructífera compañía que termina bruscamente en 1929 tras la relación fugaz de la hija de Carmen con el escritor.
El periodismo en el primer tercio del siglo XX
Authors: Pizarroso Quintero Alejandro
Published: July 2010

Se estudia la evolución de la Prensa en España desde finales del XIX hasta el inicio de la guerra civil.
Denuncia, humor y pasión en la narrativa de Colombine
Authors: Torres Nebrera Gregorio
Published: July 2010

En este artículo se abordan diversos aspectos temáticos de la narrativa de Carmen de Burgos (denuncia de defectos sociales, perspectivas humorísticas y simbolización de la pasión amorosa) en algunas de sus principales novelas: El veneno del arte, Los anticuarios, El tío de todos y Puñal de claveles.
El México de Carmen de Burgos
Authors: Portal Marta
Published: July 2010

El texto presenta en los primeros párrafos la personalidad profesional y los rasgos de estilo de Carmen de Burgos. Marta Portal hace referencia a su propio México, que ella –la autora del comentario– conoció en varias estancias en el país, de las que dejan constancia sus libros y artículos sobre México. Analiza los comentarios directos de Carmen de Burgos sobre el país visitado y descrito en varios artículos y la novela corta, La Misionera de Teotihuacán, su conocimiento histórico y cultural, además de su participación personal en cuanto ve y comenta. “Impresiones –dice Marta Portal– que podrían servir e ilustrar la mejor de las guías turísticas de hoy”.
Carmen de Burgos y Nápoles
Authors: Molina César Antonio
Published: July 2010

Se comentan las estancias de Carmen de Burgos y Ramón Gómez de la Serna en Nápoles. Su amistad con Matilde Serao, y las obras de ambos escritores con referencias a la ciudad y su historia, más concretamente, la novela de la autora, El Misericordia.
Notas sobre la prosa periodística de Carmen de Burgos
Authors: Senabre Sempere Ricardo
Published: July 2010

Como muchos autores de la época, Carmen de Burgos simultaneó el periodismo con la creación propiamente literaria. En estas páginas se intenta analizar cuáles son los rasgos esenciales de una prosa culta que, sin embargo, se dirige mediante la prensa a un público muy amplio. Se tienen en cuenta las estructuras compositivas más frecuentes, así como las creaciones metafóricas predilectas de la autora, a fin de dar una imagen de la prosa periodística que la caracteriza.
La crítica de arte en Colombine. El concepto de belleza
Authors: Gómez Alfeo María Victoria , García Rodríguez Fernando
Published: July 2010

La relación de Colombine con el arte y con los artistas es continúa en sus tertulias y en sus viajes, en los que busca la obra, y el artista, como manifestación profunda de la cultura que trata de conocer. La defensa del Greco se inscribe en la campaña del periodismo para salvar los cuadros de la capilla de San José. Las valoraciones y descripciones del arte italiano y flamenco, sus notas de viaje, nos proyectan a la relación, siempre defendida, entre pintores y poetas. Por todo ello nos atrae el conocer su posición ante la obra, es decir, su concepto de belleza que hemos analizado en sus críticas periodísticas y en sus libros de viajes.
Carmen de Burgos, traductora
Authors: Simón Palmer María del Carmen
Published: July 2010

En el primer tercio del siglo XX, Carmen de Burgos realizó una notable tarea para lograr el conocimiento de la literatura extranjera en España y tradujo más de treinta obras de autores tan variados como Ruskin, Renan, Moebius, Salgari o Rachilde. Se ha elegido ordenar sus traducciones de acuerdo con las editoriales que las publicaron para distinguir la línea editorial de cada una de ellas.
Mycobacterium tuberculosis and TLR2 Agonists Inhibit Induction of Type I IFN and Class I MHC Antigen Cross Processing by TLR9
Authors: Simmons Daimon P. , Canaday David H. , Liu Yi , Li Qing , Huang Alex , Boom W. Henry , Harding Clifford V.
Published: July 2010

Dendritic cells (DCs) cross process exogenous Ags and present them by class I MHC (MHC-I) molecules to CD8+ T cells specific for Ags from viruses and bacteria such as Mycobacterium tuberculosis. Unmethylated CpG DNA signals through TLR9 to induce type I IFN (IFN-α/β), which enhances MHC-I Ag cross processing, but lipoproteins that signal through TLR2 do not induce IFN-α/β. In these studies we observed that M. tuberculosis, which expresses agonists of both TLR9 and TLR2, did not induce production of IFN-α/β or cross processing by murine DCs. Furthermore, M. tuberculosis and TLR2 agonists inhibited induction of IFN-α/β and DC cross processing by CpG DNA. Exogenous IFN-α/β effectively enhanced cross processing of M. bovis bacillus Calmette-Guérin expressing OVA, bypassing the inhibition of induction of endogenous IFN-α/β. In addition, inhibition of TLR9-induced cross processing of M. bovis bacillus Calmette-Guérin expressing OVA could be circumvented by pretreating cells with CpG DNA to induce IFN-α/β and MHC-I cross processing before inhibitory mycobacterial TLR2 agonists were present. Inhibition of the response to one TLR by another may affect the ultimate response to pathogens like M. tuberculosis that express agonists of multiple TLRs, including TLR2 and TLR9. This mechanism may contribute to immune evasion and explain why IFN-α/β provides little contribution to host immunity to M. tuberculosis. However, downregulation of certain TLR responses may benefit the host by preventing detrimental excessive inflammation that may occur in the presence of persistent infection.
MHC Class I Presentation and Regulation by IFN in Bony Fish Determined by Molecular Analysis of the Class I Locus in Grass Carp
Authors: Chen Weihong , Jia Zhenghu , Zhang Ting , Zhang Nianzhi , Lin Changyou , Gao Feng , Wang Li , Li Xiaoying , Jiang Yinan , Li Xin , Gao George F. , Xia Chun
Published: July 2010

Beyond their sequences, little is known regarding MHC class I presentation and regulation by IFN in bony fish. In this work, the class I locus (Ctid-UBA) was isolated from a grass carp fosmid library, and its polymorphisms and tissue expression were investigated. The Ctid-UBA and Ctid-β2–microglobulin genes then were expressed and refolded, and tetramer techniques were used to identify the CTL response. The interaction between grass carp type I IFN and Ctid-UBA genes was investigated. Two fosmids coding for Ctid-UBA *0101 and Ctid-UBA *0201 genes were sequenced. The SXY box and IFN-stimulated regulatory element motifs were located from the start codons to −800 bp in Ctid-UBA. A Southern blot showed three to four bands, suggesting that grass carp contains at least three class I loci. In addition, the Ctid-UBA allelic genes are expressed in all tissue of grass carp. The three-dimensional structure of Ctid-UBA *0102 showed that the peptide-binding domain was formed by the α1 and α2 domains, which could bind several nonapeptides of grass carp hemorrhagic virus. There were 1.60% more PE-positive cells in P1(QPNEAIRSL)-immunized fish than in blank and adjuvant control groups. Additionally, recombinant grass carp IFN could regulate the expression of Ctid-UBA. These results characterize the class I presentation, CTL response, and regulation by type I IFN in bony fish.
Intereleukin-10 Promoter Polymorphism in Mild Cognitive Impairment and in Its Clinical Evolution
Authors: Arosio Beatrice , Mastronardi Luigina , Vergani Carlo , Annoni Giorgio
Published: July 2010

Specific proinflammatory alleles are associated with higher risk of Alzheimer disease (AD) in different onset age. The homozygosis for the A allele of −1082 polymorphism (G/A) of interleukin-10 (IL-10) promotes a higher risk of AD and reduced IL-10 generation in peripheral cells after amyloid stimulation. In this paper we analysed genotype and allele frequencies of this polymorphism in 138 subjects with mild cognitive impairment (MCI) diagnosed, respectively, as amnestic (a-MCI) and multiple impaired cognitive domains (mcd-MCI). The genotype frequencies were similar in a-MCI and AD subjects, whereas in mcd-MCI comparable to controls (AA genotype: 50% in a-MCI, 49.2% in AD, 28.7% in mcd-MCI and 31.8% in controls). Consequently, both allele and genotype distributions were significantly different between a-MCI and mcd-MCI (allele: , genotype: ). These results support the theory that polymorphisms of cytokine genes can affect neurodegeneration and its clinical progression. IL-10 may partly explain the conversion of a-MCI to AD or be a genetic marker of susceptibility.
On microphysical processes of noctilucent clouds (NLC): observations and modeling of mean and width of the particle size-distribution
Authors: Baumgarten G. , Fiedler J. , Rapp M.
Published: July 2010

Abstract. Noctilucent clouds (NLC) in the polar summer mesopause region have been observed in Norway (69° N, 16° E) between 1998 and 2009 by 3-color lidar technique. Assuming a mono-modal Gaussian size distribution we deduce mean and width of the particle sizes throughout the clouds. We observe a quasi linear relationship between distribution width and mean of the particle size at the top of the clouds and a deviation from this behavior for particle sizes larger than 40 nm, most often in the lower part of the layer. The vertically integrated particle properties show that 65% of the data follows the linear relationship with a slope of 0.42±0.02 for mean particle sizes up to 40 nm. For the vertically resolved particle properties (Δz = 0.15 km) the slope is comparable and about 0.39±0.03. For particles larger than 40 nm the distribution width becomes nearly independent of particle size and even decreases in the lower part of the layer. We compare our observations to microphysical modeling of noctilucent clouds and find that the distribution width depends on turbulence, the time that turbulence can act (cloud age), and the sampling volume/time (atmospheric variability). The model results nicely reproduce the measurements and show that the observed slope can be explained by eddy diffusion profiles as observed from rocket measurements.
Vertical transport rates and concentrations of OH and Cl radicals in the Tropical Tropopause Layer from observations of CO2 and halocarbons: implications for distributions of long- and short-lived chemical species
Authors: Park S. , Atlas E. L. , Jiménez R. , Daube B. C. , Gottlieb E. W. , Nan J. , Jones D. B. A. , Pfister L. , Conway T. J. , Bui T. P. , Gao R.-S. , Wofsy S. C.
Published: July 2010

Abstract. Rates for large-scale vertical transport of air in the Tropical Tropopause Layer (TTL) were determined using high-resolution, in situ observations of CO2 concentrations in the tropical upper troposphere and lower stratosphere during the NASA Tropical Composition, Cloud and Climate Coupling (TC4) campaign in August 2007. Upward movement of trace gases in the deep tropics was notably slower in TC4 than during the Costa Rica AURA Validation Experiment (CR-AVE), in January 2006. Transport rates in the TTL were combined with in situ measurements of chlorinated and brominated organic compounds from whole air samples to determine chemical loss rates for reactive chemical species, providing empirical vertical profiles for 24-h mean concentrations of hydroxyl radicals (OH) and chlorine atoms in the TTL. The analysis shows that important short-lived species such as CHCl3, CH2Cl2, and CH2Br2 have longer chemical lifetimes than the time for transit of the TTL, implying that these species, which are not included in most models, could readily reach the stratosphere and make significant contributions of chlorine and/or bromine to stratospheric loading.
Dynamic Solution Injection: a new method for preparing pptv-ppbv standard atmospheres of volatile organic compounds
Authors: Jardine K. J. , Henderson W. M. , Huxman T. E. , Abrell L. , Shartsis T.
Published: July 2010

Abstract. Proton Transfer Reaction-Mass Spectrometry (PTR-MS) and thermal desorption Gas Chromatography-Mass Spectrometry (GC-MS) allow for absolute quantification of a wide range of atmospheric volatile organic compounds (VOCs) with concentrations in the ppbv to pptv range. Although often neglected, routine calibration is necessary for accurate quantification of VOCs by PTR-MS and GC-MS. Several gas calibration methods currently exist, including compressed gas cylinders, permeation tubes, diffusion tubes, and liquid injection. While each method has its advantages and limitations, no single technique has emerged that is capable of dynamically generating accurate concentrations of complex mixtures of VOCs over a large concentration range (ppbv to pptv), is technically simple and field portable, and affordable. We present the development of a new VOC calibration technique based on liquid injection with these features termed Dynamic Solution Injection (DSI). This method consists of injecting VOCs (0.1–0.5 mM) dissolved in cyclohexane (PTR-MS) or methanol (GC-MS) into a 1.0 slpm flow of purified dilution gas in an unheated 25 mL glass vial. Upon changes in the injection flow rate (0.5–4.0 μL min−1), new VOC concentrations are reached within seconds to minutes, depending on the compound, with a liquid injection flow rate accuracy and precision of better than 7% and 4%, respectively. We demonstrate the utility of the DSI technique by calibrating a PTR-MS to seven different cyclohexane solutions containing a total of 34 different biogenic compounds including volatile isoprenoids, oxygenated VOCs, fatty acid oxidation products, aromatics, and dimethyl sulfide. In order to validate the new DSI method, a GC-MS and PTR-MS calibration intercomparison with VOC standards generated by dynamic dilution of NIST traceable permeation tubes (α-pinene, acetone, and ethanol) and a compressed gas cylinder (acetaldehyde) was made. The results revealed that while calibration of acetone is comparable between the methods, calibration curve slopes for other VOCs obtained by using permeation tubes and the compressed gas cylinder are lower than those obtained by the DSI technique by up to a factor of 2. This implies that concentration measurements of some VOCs may be overestimated using permeation tubes and/or compressed gas cylinders for calibration. Because of its high accuracy and precision, small size, low cost, and simplicity, we conclude that the Dynamic Solution Injection method will be of great use to both laboratory and field VOC studies.
The influence of iron and light on net community production in the Subantarctic and Polar Frontal Zones
Authors: Cassar N. , DiFiore P. J. , Barnett B. A. , Bender M. L. , Bowie A. R. , Tilbrook B. , Petrou K. , Westwood K. J. , Wright S. W. , Lefevre D.
Published: July 2010

Abstract. The roles of iron and light in controlling biomass and primary productivity are clearly established in the Southern Ocean. However, their influence on net community production (NCP) and carbon export remains to be quantified. To improve our understanding of NCP and carbon export production in the Subantarctic Zone (SAZ) and the northern reaches of the Polar Frontal Zone (PFZ), we conducted continuous onboard determinations of NCP as part of the Sub-Antarctic Sensitivity to Environmental Change (SAZ-Sense) study, which occurred in January–February 2007. Biological O2 supersaturation was derived from measuring O2/Ar ratios by equilibrator inlet mass spectrometry. Based on these continuous measurements, NCP during the austral summer 2007 in the Australian SAZ was approximately 43 mmol O2 m−2 d−1. Both gross primary productivity (estimated from the oxygen triple isotope anomaly) and NCP showed significant spatial variability, with larger values near the Subtropical front, and a general southward decrease. For shallower mixed layers (<50 m), dissolved Fe concentrations and Fe sufficiency, estimated from variable fluorescence, correlated strongly with NCP. At stations with deeper mixed layers, NCP was consistently low, regardless of iron sufficiency, consistent with light availability also being an important control of NCP. Our new observations provide independent evidence for the critical roles of iron and light in mediating carbon export from the Southern Ocean mixed layer.
Multifunctional Au‐Coated TiO2 Nanotube Arrays as Recyclable SERS Substrates for Multifold Organic Pollutants Detection
Authors: Li Xuanhua , Chen Guangyu , Yang Liangbao , Jin Zhen , Liu Jinhuai
Published: July 2010

A multifunctional Au‐coated TiO2 nanotube array is made via synthesis of a TiO2 nanotube array through a ZnO template, followed by deposition of Au particles onto the TiO2 surface using photocatalytic deposition and a hydrothermal method, respectively. Such arrays exhibit superior detection sensitivity with high reproducibility and stability. In addition, due to possessing stable catalytic properties, the arrays can clean themselves by photocatalytic degradation of target molecules adsorbed to the substrate under irradiation with UV light into inorganic small molecules using surface‐enhanced Raman spectroscopy (SERS) detection, so that recycling can be achieved. Finally, by detection of Rhodamine 6G (R6G) dye, herbicide 4‐chlorophenol (4‐CP), persistent organic pollutant (POP) dichlorophenoxyacetic acid (2,4‐D), and organophosphate pesticide methyl‐parathion (MP), the unique recyclable properties indicate a new route in eliminating the single‐use problem of traditional SERS substrates and show promising applications for detecting other organic pollutants.
Palladium/Tris(tert‐butyl)phosphine‐Catalyzed Suzuki Cross‐ Couplings in the Presence of Water
Authors: Lou Sha , Fu Gregory C.
Published: July 2010

Dipalladiumtris(dibenzylideneacetone)/tris(tert‐butyl)phosphonium tetrafluoroborate/potassium fluoride dihydrate [Pd2(dba)3/[HP(t‐Bu)3]BF4/KF⋅2 H2O] serves as a mild, robust, and user‐friendly method for the efficient Suzuki cross‐coupling of a diverse array of aryl and heteroaryl halides with aryl‐ and heteroarylboronic acids.
Characterization and electrical conductivity of poly(ethylene glycol)/polyacrylonitrile/multiwalled carbon nanotube composites
Authors: Aqeel Salem M. , Küçükyavuz Zuhal
Published: July 2010

Polymer blends based on poly(ethylene glycol), polyacrylonitrile, and multiwalled carbon nanotubes (MWNTs) were prepared by the solvent cast technique from the dispersion of the MWNTs in the concentration range 0–3.45 wt %. The interaction of the MWNTs with the polymer blend was confirmed by a Fourier transform infrared (FTIR) spectroscopy study. The thermal properties of the polymer blend with the MWNTs were carried out by means of differential scanning calorimetry (DSC). It was evident from DSC that the polymer/MWNTs had a high thermal stability. Scanning electron microscopy was used to study the dispersion of the MWNTs in the polymer blend. To measure the electrical conductivity, the four‐point probe method was used. The electrical conductivity showed an ionic conductivity on the order of 4.4 × 10−4 to 1.2 × 10−2 S/cm. Relative changes in the conductivity with the concentration and temperatures for the samples were analyzed. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Miscibility study of poly(vinyl chloride)/poly(methyl methacrylate‐co‐4‐vinylpyridine) by viscosimetry, DSC, and FTIR
Authors: Benmerad Mouci Fethia , Djadoun Said , Alothman Zeid A. , Aouak Taieb
Published: July 2010

The miscibility of the poly(vinyl chloride)/poly(methylmethacrylate) system were improved by introducing pyridine units into poly(methylmethacrylate) main. For this purpose, we have synthesized through a radical polymerization a series of methylmethacrylate‐co‐vinyl‐4‐pyridine copolymers of different compositions and carried out a comparative study by viscosimetry, differential scanning calorimetry, and Fourier transform infrared spectroscopic (FTIR) methods. The viscosimetric analysis using the Krigbaum‐Wall, K. K. Chee, and Compos approaches revealed that, the Poly(vinyl chloride)/poly(methylmethactylate‐co‐4‐vinylpyridine)(PVC/MMA4VP‐15) at 15 wt % of 4‐vinylpyridine systems in tetrahydrofuran are completely miscible in all proportions. The differential scanning calorimetry analysis confirmed the miscibility of these systems in all proportions by the appearance of only one glass transition temperature between those of the two pure constituents. The Kwei and Schneider approaches showed also the miscibility of this system, which is due to the specific interactions between the acidic hydrogen atom of PVC and the nitrogen of MMA4VP‐15. The use of FTIR method has confirmed the occurrence of this kind of interactions by broadening and shifting of the involved functional groups vibration bands. In this work, we have also carried out a preliminary test of sorption of THF aqueous solution by PVC and PVC/MMA4VP‐15 blend membranes. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Effect of flyash content, particle size of flyash, and type of silane coupling agents on the properties of recycled poly(ethylene terephthalate)/flyash composites
Authors: Joseph Seena , Bambola V. A. , Sherhtukade V. V. , Mahanwar P. A.
Published: July 2010

Recent time's polymer waste disposal is a challenging task as the quantity of polymer waste is increasing day by day. Here particulate composites have been developed from recycled poly(ethylene terephthalate) filled with flyash. Flyash of different particle sizes have been used, and effect of particle size and flyash content on the mechanical properties of composites has been analyzed. Tensile and flexural properties of the composites are found to increase with increase in filler content up to 15% and after that decreases due to the agglomeration of flyash particles. SEM studies also showed good dispersion at lower loadings. The use of silane coupling agents was found to increase the flyash/WPET interaction there by increase in mechanical properties is observed. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Fluorescence spectroscopy as a non invasive tool to follow in situ the polymerization in miniemulsion
Authors: Frochot Céline , Mascherin Marion , Haumont Amandine , Viriot Marie‐Laure , Marie Emmanuelle
Published: July 2010

Miniemulsion polymerization is a powerful technique to produce a whole variety of latexes with controlled colloidal and chemical properties, which has gained an increasing importance in the past years. For many applications, the following of the kinetics of polymerization is of crucial importance. In this study, we developed a technique based on the use of fluorescent probes that could be a very promising noninvasive method to follow the reaction in situ. It was possible to follow qualitatively the kinetics of methyl methacrylate (MMA) polymerization by measuring the photophysical properties of fluorescent probes sensitive to the modification of the viscosity of the microenvironment along the reaction course. Two fluorescent sensors have been considered: 1,1‐dicyano‐4‐(4′‐dimethylaminophenyl)‐1,3‐butadiene) and pyrene. In this article, we will show that using these two different fluorescent probes allow the detection of MMA polymerization in miniemulsion. The results will be compared with a classical NMR method. This method could be easily adapted to different monomers. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Miscibility enhancement through hydrogen bonding interaction of biodegradable poly(3‐hydroxybutyrate) blending with poly(styrene‐co‐vinyl phenol) copolymer
Authors: Kuo Shiao‐Wei , Liu Wei‐Chen
Published: July 2010

Differential scanning calorimetry, one‐ and two‐dimensional Fourier transform infrared (FTIR), and solid state nuclear magnetic resonance (NMR) spectroscopy have been used to investigate the miscibility of and specific interactions between poly(styrene‐co‐vinyl phenol) (PSOH) and poly(3‐hydroxybutyrate) (PHB) upon varying the vinyl phenol content of the PSOH copolymer. The FTIR and solid state NMR spectra revealed that the phenol units of PVPh interact with the carbonyl groups of PHB through intermolecular hydrogen bonding. A miscibility window exists when the vinyl phenol fraction in the copolymer is greater than 22 mol % in the PSOH/PHB blend system, as predicted using the Painter–Coleman association model. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Surface modification of MWNTs with BA‐MMA‐GMA terpolymer by single‐step grafting technique
Authors: Xia Ru , Li Minghua , Zhang Yuchuan , Qian Jiasheng , Yuan Xiaoyou
Published: July 2010

In this article, a facile strategy was developed to prepare BA‐MMA‐GMA/MWNTs (multiwalled carbon nanotubes) hybrid nanoparticles as nanofillers in rubber by single‐step grafting technique. First, a new macromolecular surface modifier butyl acrylate (BA)‐α‐methyl methacrylate(MMA)‐glycidyl methacrylate (GMA) terpolymer was synthesized via radical copolymerization. Afterward, this terpolymer modifier was covalently grafted onto the surface of crude MWNTs by single‐step grafting technique. The structure, surface properties, and thermal stability of modified MWNTs were systematically investigated by FTIR, TGA, and TEM. FTIR results showed that BA‐MMA‐GMA terpolymer was successfully grafted onto the surface of MWNTs. TGA indicated that the optimum mass fraction of macromolecular modifier coated on the surface of MWNTs was 9 wt %. TEM images revealed that an organic coating layer was formed and the modified MWNTs showed good dispersibility in acetone. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
PET/PC blends: Effect of chain extender and impact strength modifier on their structure and properties
Authors: Pesetskii S. S. , Jurkowski B. , Filimonov O. V. , Koval V. N. , Golubovich V. V.
Published: July 2010

Methylene diphenyl diisocyanate (MDI) affects the morphology, rheological, mechanical, and relaxation properties, as well as tendency to crystallize of PET in PET/PC/(PP/EPDM) ternary blends produced by the reactive extrusion. Irrespective of the blend phase structure, the introduction of MDI increases the melt viscosity (MFI dropped), resulting from an increase in the molecular weight of the polymer chains; the PET crystallinity was also reduced. MDI favors compatibility of PET with PC in PET/PC/(PP/EPDM) blends. This is explained by intensified interphase interactions on the level of segments of macromolecules as well as monomer units. The presence of MDI causes a substantial rise in the dynamic shear modulus within the high‐elastic region of PET (for temperature range between Tg,PET and that of PET cold crystallization); the processes of PET cold crystallization and melt crystallization become retarded; the glass‐transition temperatures for PET and PC become closer to each other. MDI affects insignificantly the blend morphology or the character of interactions between the disperse PP/EPDM blend and PET/PC as a matrix. PP/EPDM reduces the intensity of interphase interactions in a PET/PC/(PP/EPDM), but a rise in the degree of material heterogeneity. MDI does not change the mechanism of impact break‐down in the ternary blends mentioned above. Increased impact strength of MDI‐modified materials can be explained by higher cohesive strength and resistance to shear flow at impact loading. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Electropolymerization kinetics of a binary mixture of o‐phenylenediamine and 2‐aminobenzothiazole and characterization of the obtained polymer films
Authors: Sayyah S. M. , Abd El‐Rehim S. S. , Kamal S. M. , El‐Deeb M. M. , Azooz R. E.
Published: July 2010

Poly(o‐phenylenediamine‐co‐2‐aminobenzothiazole), P(oPD‐co‐2ABT), has been synthesized electrochemically from an aqueous acid medium. The initial rate of electrocopolymerization reaction on platinum electrode is small, and the rate law is Rate = KE [Na2SO4]0.48 [HCl]1.09 [M]2.08. The apparent activation energy (Ea) is found to be 57.44 kJ mol−1. The polymer films obtained have been characterized by cyclic voltammetry, X‐ray diffraction, elemental analysis, TGA, scanning electron microscopy, and IR‐spectroscopy. The mechanism of the electrochemical polymerization reaction has been discussed. The monomer reactivity ratios (r1 and r2) were calculated using Fineman‐Röss method. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Preparation of phenolic resin/organized expanded vermiculite nanocomposite and its application in brake pad
Authors: Yu Jianying , He Jia , Ya Chongqing
Published: July 2010

Phenolic resin (PF)/organized expanded vermiculite (OEVMT) nanocomposite was prepared via melt intercalation with EVMT organically treated using benzyldimethyloctadecylammonium. The results of the PF/OEVMT structure characterized by X‐ray diffraction and transmission electron microscopy showed that the PF/OEVMT nanocomposite formed exfoliated and intercalated mixed structure. Thermogravimetric analysis indicated that the thermal decomposition temperature of the PF/OEVMT nanocomposite (482.6°C) was higher than that of pristine PF (433.9°C) in air atmosphere. The brake pad based on PF/OEVMT nanocomposite were also prepared. The friction and wear tests illustrated that the brake pad based on PF/OEVMT had more stable friction coefficient and lower wear rate than that of the brake pad based on PF. Scanning electron microscopy also showed that the brake pad based on PF/OEVMT nanocomposite has excellent high temperature wear‐resistance. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Self‐emulsifying binders for water‐borne coatings—Synthesis and characteristics of maleated alkyd resins
Authors: Heiskanen Nina , Jämsä Saila , Paajanen Leena , Koskimies Salme
Published: July 2010

Self‐emulsifying binders have been prepared by reaction of long oil alkyd resins with maleated derivatives of fatty acids. These binders were dispersed in water without use of external surfactants and free from volatile organic compounds. The binders were evaluated based on their performance properties, including penetration and moisture repellency ability against commercial references. According this study, binders with interesting properties have been prepared. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Fabrication of surfactant‐removed polymer composites with single‐walled carbon nanotube networks
Authors: Zhang Cheng , Wen Bin , Gao Lei , Chen Yongming , Yang Mingshu
Published: July 2010

Polystyrene (PS) composites with a network of single‐walled carbon nanotubes (SWNTs) were fabricated by using monodispersed PS micospheres. First, PS spheres and surfactant‐dispersed SWNTs were mixed in water, then a hybrid cake was obtained by filtration via a microporous membrane and the SWNTs were filled within the spaces of packed polymer spheres. At this stage, the surfactants for dispersing SWNTs were totally removed from the composites by a thorough washing. Then the composite films with SWNT networks were obtained by compression molding at 160°C. Structure of the composites had been characterized by transmission electron microscopy and scanning electron microscopy. The present SWNT composites showed a low percolation threshold of electrical conductivities. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Prototype of Low Thermal Expansion Materials: Fabrication of Mesoporous Silica/Polymer Composites with Densely Filled Polymer inside Mesopore Space
Authors: Kiba Shosuke , Suzuki Norihiro , Okawauchi Yoshinori , Yamauchi Yusuke
Published: July 2010

A prototype of novel low thermal expansion materials using mesoporous silica particles is demonstrated. Mesoporous silica/polymer composites with densely filled polymer inside the mesopore space are fabricated by mechanically mixing both organically modified mesoporous silica and epoxy polymer. The mesopores are easily penetrated by polymers as a result of the capillary force during the mechanical composite processing. Furthermore, we propose a new model of polymer mobility restriction using mesoporous silica with a large pore space. The robust inorganic frameworks covering the polymer effectively restrict the polymer mobility against thermal energy. As a result, the degree of total thermal expansion of the composites is drastically decreased. From the mass‐normalized thermal mechanical analysis (TMA) charts of various composites with different amounts of mesoporous silica particles, it is observed that the coefficient of thermal expansion (CTE) values gradually increase with an increase of the polymer amount outside the mesopores. It is proven that the CTE values in the range over the glass‐transition temperatures (Tg) are perfectly proportional to the outside polymer amounts. Importantly, the Y‐intercept of the relation equation obtained by a least‐square method is the CTE value and is almost zero. This means that thermal expansion does not occur if no polymers are outside the mesopores. Through such a quantative discussion, we clarify that only the outside polymer affects the thermal expansion of the composites, that is, the embedded polymers inside the mesopores do not expand at all during the thermal treatment.
Cobalt‐Catalyzed Addition of Styrylboronic Acids to 2‐Vinylpyridine Derivatives
Authors: Kobayashi Tsuneyuki , Yorimitsu Hideki , Oshima Koichiro
Published: July 2010

Treatment of 2‐vinyl nitrogen‐containing heteroaromatic compounds with styrylboronic acid in the presence of a cobalt catalyst and a base results in an addition reaction to afford the corresponding 4‐phenyl‐3‐butenyl heteroarenes. The adjacent nitrogen atom is essential for the promotion of the reaction because the nitrogen accelerates the addition of the styryl cobalt species, generated by transmetalation, onto the vinyl group. The reaction represents a rare example of cobalt catalysis in the reactions of organoboronic acids.
MHD waves in the solar north polar coronal hole
Authors: Devlen E. , Pekünlü E.R.
Published: July 2010

The effects, hitherto not treated, of the temperature and the number density gradients, both in the parallel and the perpendicular direction to the magnetic field, of O VI ions, on the MHD wave propagation characteristics in the solar North Polar Coronal Hole are investigated. We investigate the magnetosonic wave propagation in a resistive MHD regime where only the thermal conduction is taken into account. Heat conduction across the magnetic field is treated in a non‐classical approach wherein the heat is assumed to be conducted by the plasma waves emitted by ions and absorbed at a distance from the source by other ions. Anisotropic temperature and the number density distributions of O VI ions revealed the chaotic nature of MHD standing wave, especially near the plume/interplume lane borders. Attenuation length scales of the fast mode is shown not to be smoothly varying function of the radial distance from the Sun (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)