bluuebunny/crossref_metadata_2025 huggingface dataset:
Short hairpin RNAs specific to human cytomegalovirus terminase subunit pUL89 prevent viral maturation
Authors: Thoma Corina , Bogner Elke
Published: May 2010

Background

In order to define the role of the human cytomegalovirus (HCMV) small terminase subunit pUL89, analysis by RNA interference was applied.

Methods

Cell lines expressing pUL89-specific short hairpin RNAs (shRNAs) were constructed by transduction of shR-NAs via infection with retroviral vectors. These cell lines were infected with HCMV AD169 and were analysed for pUL89 expression, viral yield, plaque reduction, amount of viral DNA and particle formation.

Results

After infection of the cell lines with HCMV, the expression of pUL89 was reduced by up to 86% for shRNA_A and 84% for shRNA_B at the later time points of infection. Cell lines expressing shRNA_C and the control had no effect on the pUL89 expression level. In addition, the inhibitory effect corresponded to a decrease in viral growth kinetics, viral DNA and plaque formation. Analysis by electron microscopy demonstrated that infection of cells expressing pUL89-specific shRNA_A and shRNA_B resulted in a complete inhibition of viral particle formation.

Conclusions

HCMV is a serious life-threatening opportunistic pathogen in immunocompromised patients. Because of multiple problems caused by the current available drugs, development of new strategies are needed. Our data clearly demonstrate that pUL89-specific shRNAs mediated the inhibition of formation of replicative infectious particles and therefore represent a new promising mechanism for antiviral therapy against HCMV infection.
Genomic events contributing to the high prevalence of amantadine-resistant influenza A/H3N2
Authors: Zaraket Hassan , Saito Reiko , Suzuki Yasushi , Suzuki Yoshiyuki , Caperig-Dapat Isolde , Dapat Clyde , Shabana Iman I , Baranovich Tatiana , Suzuki Hiroshi
Published: May 2010

Background

The prevalence of amantadine-resistant influenza A/H3N2 viruses (belonging to the N-lineage), possessing an S31N mutation in the M2 protein and S193F and D225N substitutions in their HA1 subunit, has significantly increased worldwide since 2005. The aim of this study was to clarify the genomic events contributing to the evolution and continuity of the N-lineage amantadine-resistant viruses.

Methods

The full genome sequence of A/H3N2 isolates, including both amantadine-resistant and amantadine-sensitive viruses, collected in Japan between 2006 and 2008, was determined and phylogenetically compared with isolates obtained from the database.

Results

On the basis of the full genome sequence analysis, the N-lineage could be further divided into three genetically related clades: N1 (A/Wisconsin/67/2005-like amantadine-resistant viruses from years 2005–2007), N2 (amantadine-sensitive viruses from 2007) and N3 (A/Brisbane/10/2007-like amantadine-resistant viruses from 2007 and 2008). The 2006/2007 season showed cocirculation of antigenic variants of amantadine-resistant viruses of clades N1 and N3 in addition to the N2-sensitive viruses. In the 2007/2008 season, the clade N3 amantadine-resistant lineage dominated and replaced other strains. Phylogenetic analysis of each individual segment suggested that N2 and N3 were generated from two independent reassortment events involving clade N1 viruses and pre-N- lineage strains.

Conclusions

Our data show that several reassortment events have contributed to the evolution of amantadine-resistant A/H3N2 strains and, consequently, to the successful spread of this lineage. Although amantadine resistance is caused by single amino acid mutations in the M2 protein, genome-wide adjustment involving multiple genes appears to be necessary to obtain efficient replication and transmission of resistant viruses. Such adjustments are attainable through reassortment of segments among different virus lineages.
Genetics and Genomics Resources for Nurses
Authors: De Sevo Margot R.
Published: May 2010

The American Association of Colleges of Nurses document,
The Essentials of Baccalaureate Education for Professional Nursing Practice
, repeatedly refers to the need for undergraduate students to be familiar with genetic and genomic information. To meet the need for access to timely, reliable genetic and genomic information, this article includes an annotation of 16 Web sites.
Efficacy of Podcasting: Use in Undergraduate and Graduate Programs in a College of Nursing
Authors: Schlairet Maura C.
Published: May 2010

The aim of this project was to create podcasts of classroom lectures from select courses across programs in a college of nursing and to explore associated outcomes using a Web-based course evaluation framework. Seventy undergraduate, second-degree, and graduate nursing students participated. Findings suggest that nurse educators can leverage students’ positive attitudes and technologic skills with minimal investment of dollars and no impact on class attendance, building high-quality podcasts that align with students’ unique learning environments and goals. Faculty should consider specific student attributes and associated needs when developing podcasts and in providing guidance and support for students who use these learning tools.
Responding to Poor-Quality Care During Research in Nursing Homes
Authors: Krause Melanie R. , Palmer Janice L. , Bowers Barbara J. , Buckwalter Kathleen C.
Published: May 2010

For nurse researchers, responding appropriately to resident abuse is straightforward: The abuse must be reported. However, responding to care that is of poor quality—where care practices are problematic but do not meet the definition of reportable abuse—is not so straightforward. Decision making may be influenced by ethical and professional principles, as well as self-interest to complete a research project. The purpose of this article is to provoke a dialogue about a dilemma faced by many researchers conducting research in long-term care: responding to poor-quality care that does not meet the state's definition of resident abuse. We will accomplish this by providing a real-life situation faced by a novice researcher conducting her first funded research project, identifying some of the important considerations and possible responses by nurse researchers. Optimally, nurse researchers will develop a plan for responding to poor care before beginning the study.
Magnitudes and controls of organic and inorganic carbon flux through a chain of hard‐water lakes on the northern Great Plains
Authors: Finlay K. , Leavitt P. R. , Patoine A. , Patoine A. , Wissel B.
Published: May 2010

Whole‐lake carbon (C) mass‐balance budgets were constructed for a chain of six hard‐water lakes to quantify the relative importance of organic carbon (OC) and inorganic carbon (IC) exchanges between atmosphere, water column, sediments, and rivers. Mean summer C fluxes were calculated for each lake during the ice‐free periods (May to September) of 1995‐2007 by measuring deposition of IC and OC in lake sediments, export of C to outflow rivers, lotic C influxes, and atmospheric exchange of CO2. Unlike soft‐water lakes, IC in rivers accounted for 68.2‐85.6% of total C (TC) influx to these hard‐water lakes, CO2 efflux accounted for 0‐44.5% of total C export (median 2.8%), and sedimentation buried similar amounts of OC and IC. Deposition of C in sediments accounted for 1.8‐61.7% of total export and was correlated to water residence time, while C efflux through rivers accounted for 32.6‐98.2% of total export, mainly as IC (69.6‐85.1% of TC). Unexpectedly, estimates of net ecosystem production based on OC mass balances suggested that all lakes were autotrophic (production > respiration) during summer, despite elevated dissolved organic carbon content (5.6‐16.1 mg C L‐1), pCO2 values, and net CO2 emissions to the atmosphere from three lakes. We conclude that C fluxes within and among these hard‐water lakes are regulated by hydrologic inputs of dissolved IC rather than by lake metabolism, IC and OC pathways are only loosely coupled, and future climate variability will alter C fluxes in similar lakes mainly through regulation of mass transfer from land.
The roles of sulfuric acid in new particle formation and growth in the mega-city of Beijing
Authors: Yue D. L. , Hu M. , Zhang R. Y. , Wang Z. B. , Zheng J. , Wu Z. J. , Wiedensohler A. , He L. Y. , Huang X. F. , Zhu T.
Published: May 2010

Abstract. Simultaneous measurements of gaseous sulfuric acid and particle number size distributions were performed to investigate aerosol nucleation and growth during CAREBeijing-2008. The analysis of the measured aerosols and sulfuric acid with an aerosol dynamic model shows the dominant role of sulfuric acid in new particle formation (NPF) process but also in the subsequent growth in Beijing. Based on the data of twelve NPF events, the average formation rates (2–13 cm−3 s−1) show a linear correlation with the sulfuric acid concentrations (R2=0.85). Coagulation seems to play a significant role in reducing the number concentration of nucleation mode particles with the ratio of the coagulation loss to formation rate being 0.41±0.16. The apparent growth rates vary from 3 to 11 nm h−1. Condensation of sulfuric acid and its subsequent neutralization by ammonia and coagulation contribute to the apparent particle growth on average 45±18% and 34±17%, respectively. The 30% higher concentration of sulfate than organic compounds in particles during the seven sulfur-rich NPF events but 20% lower concentration of sulfate during the five sulfur-poor type suggest that organic compounds are an important contributor to the growth of the freshly nucleated particles, especially during the sulfur-poor cases.
Enhancing effect of dimethylamine in sulfuric acid nucleation in the presence of water – a computational study
Authors: Loukonen V. , Kurtén T. , Ortega I. K. , Vehkamäki H. , Pádua A. A. H. , Sellegri K. , Kulmala M.
Published: May 2010

Abstract. We have studied the hydration of sulfuric acid – ammonia and sulfuric acid – dimethylamine clusters using quantum chemistry. We calculated the formation energies and thermodynamics for clusters of one ammonia or one dimethylamine molecule together with 1–2 sulfuric acid and 0–5 water molecules. The results indicate that dimethylamine enhances the addition of sulfuric acid to the clusters much more efficiently than ammonia when the number of water molecules in the cluster is either zero, or greater than two. Further hydrate distribution calculations reveal that practically all dimethylamine-containing two-acid clusters will remain unhydrated in tropospherically relevant circumstances, thus strongly suggesting that dimethylamine assists atmospheric sulfuric acid nucleation much more effectively than ammonia.
Sensitivity of a global model to the uptake of N2O5 by tropospheric aerosol
Authors: Macintyre H. L. , Evans M. J.
Published: May 2010

Abstract. The uptake of N2O5 on aerosol impacts atmospheric concentrations of NOx and so O3, OH, and hence CH4. Laboratory studies show significant variation in the rate of uptake, with a general decline in the value of γN2O5 over the last decade as increasingly relevant tropospheric proxies have been studied. In order to understand the implication of this decline for tropospheric composition, a global model of tropospheric chemistry and transport (GEOS-Chem) is run with differing values of γN2O5 (0.0, 10−6, 10−4, 10−3, 5×10−3, 10−2, 2×10−2, 0.1, 0.2, 0.5, and 1.0). We identify three regimes in the model response. At low values of γN2O5, the model shows reduced sensitivity to the value of γN2O5 as heterogeneous uptake of N2O5 does not provide a significant pathway to perturb NOx burdens. At high values of γN2O5 the model again shows reduced sensitivity to the value of γN2O5, as NOx loss through heterogeneous removal of N2O5 is limited by the rate of production of NO3 rather than the rate of heterogeneous uptake. At intermediate values of γN2O5 the model shows significant sensitivity to the value of γN2O5. We find regional differences in the model's response to changing γN2O5. Regions with high aerosol surface area and low temperatures show NO3 production becoming rate limiting at lower γN2O5 values than regions with lower aerosol surface area and higher temperatures. The northern extra-tropics show significant sensitivity to the value of γN2O5 at values consistent with current literature (0.001–0.02), thus an accurate description of γN2O5 is required for adequate simulation of O3 burdens and long-range transport of pollutants in this region. Our model simulations also provide insight into model sensitivity to changes in aerosol load through changing surface area for different values of γN2O5. We find little change in the global sensitivity to γN2O5 in the range 0.05 to 1.0, but a significant drop in sensitivity below this range. Thus simulations of the coupled impact of both chemistry and aerosol changes will be sensitive to the choice of γN2O5.
13-month climatology of the aerosol hygroscopicity at the free tropospheric site Jungfraujoch (3580 m a.s.l.)
Authors: Kammermann L. , Gysel M. , Weingartner E. , Baltensperger U.
Published: May 2010

Abstract. A hygroscopicity tandem differential mobility analyzer (HTDMA) was operated at the high-alpine site Jungfraujoch in order to characterize the hygroscopic diameter growth factors of the free tropospheric Aitken and accumulation mode aerosol. More than ~5000 h of valid data were collected for the dry diameters D0=35, 50, 75, 110, 165, and 265 nm during the 13-month measurement period from 1 May 2008 through 31 May 2009. No distinct seasonal variability of the hygroscopic properties was observed. Annual mean hygroscopic diameter growth factors (D/D0) at 90% relative humidity were found to be 1.34, 1.43, and 1.46 for D0=50, 110, and 265 nm, respectively. This size dependence can largely be attributed to the Kelvin effect because corresponding κ~values are virtually independent of size. The mean hygroscopicity of the Aitken and accumulation mode aerosol at the free tropospheric site Jungfraujoch was found to be κ≈0.24 with little variability throughout the year. The impact of Saharan dust events, a frequent phenomenon at the Jungfraujoch, on aerosol hygroscopicity was shown to be negligible for D0<265 nm. Thermally driven injections of planetary boundary layer (PBL) air, particularly observed in the early afternoon of summer days with convective anticyclonic weather conditions, lead to a decrease of aerosol hygroscopicity. However, the effect of PBL influence is not seen in the annual mean hygroscopicity data because the effect is small and those conditions (weather class, season and time of day) with PBL influence are relatively rare. Aerosol hygroscopicity was found to be virtually independent of synoptic wind direction during advective weather situations, i.e. when horizontal motion of the atmosphere dominates over thermally driven convection. This indicates that the hygroscopic behavior of the aerosol observed at the Jungfraujoch can be considered to be representative of the lower free troposphere on at least a regional if not continental scale.
Columnar aerosol size distribution function obtained by inversion of spectral optical depth measurements for the Zanjan, Iran
Authors: Masoumi A. , Bayat A. , Khalesifard H. R.
Published: May 2010

Abstract. We are reporting the calculated values of columnar aerosol size distribution function for atmosphere of Zanjan, a city in Northwest Iran (36.70° N, 48.51° E). Ground-based measurements of the total optical depth of the Zanjan atmosphere at 440 nm, 670 nm, 870 nm, and 1020 nm are recorded using a Cimel CE318-2 sunphotometer in the period of October 2006 to September 2008. The spectral aerosol optical depth has been obtained by subtraction of molecular optical depth from the total optical depth for each wavelength channel. Also the Ångström exponent is determined by a logarithmic fit to the aerosol optical depth when it is plotted versus the logarithm of the wavelength. Daily averages of the measured aerosol optical depth and Ångström exponent values have been implemented in an inversion algorithm for calculation of the columnar aerosol size distribution function. In this algorithm, the aerosols are considered as spheres of different size and refractive index of 1.45. We found that for 82% of the days, aerosols are in the coarse mode. For these days, more than 50% of the aerosol volume concentration has a radius >1 μm. We believe this is related to the geographical location of Zanjan in a mostly dry area and subject to frequent dust winds.
Are there optical differences between storm-time substorms and isolated substorms?
Authors: Hoffman R. A. , Gjerloev J. W. , Frank L. A. , Sigwarth J. W.
Published: May 2010

Abstract. We have performed an extensive analysis of auroral optical events (substorms) that occurred during the development of the main phase of magnetic storms. Using images from the Earth Camera on the Polar spacecraft (Frank et al., 1995), we compared the optical emission features of substorms occurring during 16 expansion phases of magnetic storms with the features of isolated substorms occurring during non-storm times. The comparison used two techniques, visual inspection and statistical comparisons. The comparisons were based on the common characteristics seen in isolated substorms that were initially identified by Akasofu (1964) and quantified by Gjerloev et al. (2008). We find that when auroral activity does occur during main phase development the characteristics of the aurora are very dissimilar to those of the classical isolated substorm. The primary differences include the lack of a surge/bulge, lack of bifurcation of the aurora, much shorter expansion phases, and greater intensities. Since a surge/bulge and bifurcation of the aurora are characteristics of the existence of a substorm current wedge, a key component of the magnetosphere-ionosphere current system during substorms, the lack of this component would indicate that the classical substorm model does not apply to the storm time magnetosphere-ionosphere current system. Rather several of the analyses suggest that the storm-time substorms are associated more closely with the auroral oval, at least spatially, and, therefore, probably with the plasma sheet dynamics during the main phase development. These results then must call into question the widely held assumption that there is no intrinsic difference between storm-time substorms and classical isolated substorms.
Large-Eddy Simulation on turbulent flow and plume dispersion over a 2-dimensional hill
Authors: Nakayama H. , Nagai H.
Published: May 2010

Abstract. The dispersion analysis of airborne contaminants including radioactive substances from industrial or nuclear facilities is an important issue for air quality maintenance and safety assessment. In Japan, many nuclear power plants are located at complex coastal terrains. In these cases, terrain effects on the turbulent flow and plume dispersion should be investigated. In this study, we perform Large-Eddy Simulation (LES) of turbulent flow and plume dispersion over a 2-dimensional hill flow and investigate the characteristics of mean and fluctuating concentrations.
ESCIMO.spread – a spreadsheet-based point snow surface energy balance model to calculate hourly snow water equivalent and melt rates for historical and changing climate conditions
Authors: Strasser U. , Marke T.
Published: May 2010

Abstract. This paper describes the spreadsheet-based point energy balance model ESCIMO.spread which simulates the energy and mass balance as well as melt rates of a snow surface. The model makes use of hourly recordings of temperature, precipitation, wind speed, relative humidity, global and longwave radiation. The effect of potential climate change on the seasonal evolution of the snow cover can be estimated by modifying the time series of observed temperature and precipitation by means of adjustable parameters. Model output is graphically visualized in hourly and daily diagrams. The results compare well with weekly measured snow water equivalent (SWE). The model is easily portable and adjustable, and runs particularly fast: hourly calculation of a one winter season is instantaneous on a standard computer. ESICMO.spread can be obtained from the authors on request (contact: ulrich.strasser@uni-graz.at).
Modelling soil moisture at SMOS scale by use of a SVAT model over the Valencia Anchor Station
Authors: Juglea S. , Kerr Y. , Mialon A. , Wigneron J.-P. , Lopez-Baeza E. , Cano A. , Albitar A. , Millan-Scheiding C. , Carmen Antolin M. , Delwart S.
Published: May 2010

Abstract. The main goal of the SMOS (Soil Moisture and Ocean Salinity) mission is to deliver global fields of surface soil moisture and sea surface salinity using L-band (1.4 GHz) radiometry. Within the context of the Science preparation for SMOS, the Valencia Anchor Station (VAS) experimental site, in Spain, was chosen to be one of the main test sites in Europe for Calibration/Validation (Cal/Val) activities. In this framework, the paper presents an approach consisting in accurately simulating a whole SMOS pixel by representing the spatial and temporal heterogeneity of the soil moisture fields over the wide VAS surface (50×50 km2). Ground and meteorological measurements over the area are used as the input of a Soil-Vegetation-Atmosphere-Transfer (SVAT) model, SURFEX (Externalized Surface) - module ISBA (Interactions between Soil-Biosphere-Atmosphere) to simulate the spatial and temporal distribution of surface soil moisture. The calibration as well as the validation of the ISBA model are performed using in situ soil moisture measurements. It is shown that a good consistency is reached when point comparisons between simulated and in situ soil moisture measurements are made. Actually, an important challenge in remote sensing approaches concerns product validation. In order to obtain an representative soil moisture mapping over the Valencia Anchor Station (50×50 km2 area), a spatialization method is applied. For verification, a comparison between the simulated spatialized soil moisture and remote sensing data from the Advanced Microwave Scanning Radiometer on Earth observing System (AMSR-E) and from the European Remote Sensing Satellites (ERS-SCAT) is performed. Despite the fact that AMSR-E surface soil moisture product is not reproducing accurately the absolute values, it provides trustworthy information on surface soil moisture temporal variability. However, during the vegetation growing season the signal is perturbed. By using the polarization ratio a better agreement is obtained. ERS-SCAT soil moisture products are also used to be compared with the simulated spatialized soil moisture. However, the lack of soil moisture data from the ERS-SCAT sensor over the area (45 observations for one year) prevented capturing the soil moisture variability.
Spatial and temporal variability of snow depth and ablation rates in a small mountain catchment
Authors: Grünewald T. , Schirmer M. , Mott R. , Lehning M.
Published: May 2010

Abstract. The spatio-temporal variability of the mountain snow cover determines the avalanche danger, snow water storage, permafrost distribution and the local distribution of fauna and flora. Using a new type of terrestrial laser scanner, which is particularly suited for measurements of snow covered surfaces, snow depth was monitored in a high alpine catchment during an ablation period. From these measurements snow water equivalents and ablation rates were calculated. This allowed us for the first time to obtain a high resolution (2.5 m cell size) picture of spatial variability of the snow cover and its temporal development. A very high variability of the snow cover with snow depths between 0–9 m at the end of the accumulation season was observed. This variability decreased during the ablation phase, while the dominant snow deposition features remained intact. The average daily ablation rate was between 15 mm/d snow water equivalent at the beginning of the ablation period and 30 mm/d at the end. The spatial variation of ablation rates increased during the ablation season and could not be explained in a simple manner by geographical or meteorological parameters, which suggests significant lateral energy fluxes contributing to observed melt. It is qualitatively shown that the effect of the lateral energy transport must increase as the fraction of snow free surfaces increases during the ablation period.
Palladium‐Catalyzed Aerobic Oxidation of Naturally Occurring Allylbenzenes as a Route to Valuable Fragrance and Pharmaceutical Compounds
Authors: Parreira Luciana A. , Menini Luciano , da Cruz Santos Joyce C. , Gusevskaya Elena V.
Published: May 2010

A palladium‐catalyzed, aerobic oxidation of naturally occurring allylbenzenes, i.e., eugenol, methyleugenol, safrole, and estragole, in dimethylacetamide/water solutions under mild conditions has been developed, in which palladium(II) chloride is used in the absence of co‐catalysts or special stabilizing ligands as the sole and recyclable catalyst. Methyl ketones that are important for the flavour and pharmaceutical industries have been obtained in good to excellent yields with low catalyst loadings (1–2 mol%) and high average turnover frequencies. This simple catalytic method represents an ecologically benign and economically attractive route to industrially valuable compounds starting from renewable substrates easily available from essential oils.
Enrichment of coal‐bed methane by PSA complemented with CO2 displacement
Authors: Liu Congmin , Zhou Yaping , Sun Yan , Su Wei , Zhou Li
Published: May 2010

A PSA cycle complemented with CO2 displacement was studied for enriching coal‐bed methane (CBM). The column was first pressurized to the adsorption pressure with feed gas, and then N2 was produced at column top in step 2. The feed gas switched to CO2 at the end of step 2, and the adsorbed CH4 was displaced and pushed to column top by CO2 becoming the second column‐top product in step 3. The CO2 stream was shut off before it broke through the sorption bed. Then bed regeneration followed. A series of CH4/N2 mixtures containing 17.62 to 51.33% CH4 was used for feed gas. It was experimentally shown that the product concentration was higher than 90%, and methane recovery was higher than 98% even for the feed of low‐methane concentration. Displacement at ambient pressure was shown more efficient than the displacement at adsorption pressure for the enrichment. © 2010 American Institute of Chemical Engineers AIChE J, 2011
Functionalization of multiwalled carbon nanotubes with amphiphilic poly(aspartic acid)
Authors: Ji Peijun , Yang Mei , Feng Wei
Published: May 2010

A new method to functionalize multiwalled carbon nanotubes (MWNTs) with amphiphilic poly(aspartic acid) was investigated. The amphiphilic polymer (PASP‐C16) was synthesized by thermal condensation and aminolysis by hexadecylamine, followed by hydrolysis of the remaining succinimide units in the polymer backbone. The functionalization of MWNTs was achieved by physical adsorption of the biopolymer onto the surfaces of MWNTs. Ultraviolet‐visible (UV‐vis) spectra showed that the functionalized MWNTs had a good aqueous dispersity and solubility. The interaction of PASP‐C16 with MWNTs was investigated by analyzing X‐ray diffraction (XRD) patterns, circular dichroism (CD), spectra and high‐resolution transmission electron microscopy (HRTEM). From the XRD patterns, it can be known that the aggregate of PASP‐C16 due to intermolecular interaction between hexadecyl chains has been reduced when the polymer interacting with MWNTs. CD spectra indicated that the interaction of hexadecyl chains of PASP‐C16 with the wall of MWNTs is the major interaction between PASP‐C16 and MWNTs, and MWNTs were covered by the poly(aspatic acid) backbone. © 2010 American Institute of Chemical Engineers AIChE J, 2011
Wax deposition modeling of oil/water stratified channel flow
Authors: Huang Zhenyu , Senra Michael , Kapoor Ravi , Fogler H. Scott
Published: May 2010

Wax deposition modeling becomes complicated when multiphase flow is involved. Empirical heat and mass transfer correlations are unreliable for multiphase deposition modeling and full scale computational fluid dynamics calculations require expensive computational intensity. In this work, numerical methods are used to study wax deposition in oil/water stratified flow through a channel. A unidirectional flow analysis is used to calculate the nonisothermal hydrodynamics and mass transfer. It was found that the change in the position of the oil/water interface throughout the channel must be taken into accounted for the mass balance to be valid. Unfortunately, this change has not been accounted for in all previous studies. In addition, the growth of the wax deposit as a function of time along with the effect of oil/water flow rate ratio is discussed. The presence of water significantly reduces the severity of wax deposition by altering the heat and mass transfer characteristics. © 2010 American Institute of Chemical Engineers AIChE J, 2011
Carben‐Übergangsmetallkomplexe durch zweifache C‐H‐Bindungsaktivierung
Authors: Werner Helmut
Published: May 2010

Die Aktivierung einer einzelnen sp3‐C‐H‐Bindung von Alkanen und ihren Derivativen durch elektronenreiche Übergangsmetallkomplexe wurde seit den 1982 erschienenen bahnbrechenden Arbeiten von Bergman und Graham zu einem viel bearbeiteten Forschungsprojekt. Zehn Jahre später wurde gezeigt, dass Verbindungen der 5d‐Elemente, z. B. von Osmium und Iridium, auch zu einer zweifachen α‐C‐H‐Bindungsaktivierung von Alkan‐ oder Cycloalkanderivaten fähig sind, sofern diese eine funktionelle Gruppe wie OR oder NR2 besitzen. Damit war ein neuer Zugang zu Carbenkomplexen der Übergangsmetalle vom Fischer‐Typ eröffnet. Nachfolgende Arbeiten konzentrierten sich zuerst auf die Umwandlung von Alkyl(methyl)‐ und Aryl(methyl)ethern in Oxocarben‐ und von Dimethylaminen in Aminocarbenliganden. Kürzlich wurde gezeigt, dass so hergestellte quadratisch‐planare Oxocarbeniridium(I)‐Komplexe zu einem ungewöhnlichen Reaktivitätstyp befähigt sind. Sie reagieren mit CO2 , CS2 , COS, PhNCO und PhNCS gemäß einer Atom‐ oder Gruppentransfermetathese, für die es bisher kein Beispiel gibt. Organoazide RN3 und N2O verhalten sich ähnlich. Jüngste Ergebnisse weisen darauf hin, dass solche Metathesereaktionen auch katalytisch durchgeführt werden können, wodurch sich eine neue Möglichkeit zur Funktionalisierung von C‐H‐Bindungen bietet.
Carbene–Transition Metal Complexes Formed by Double CH Bond Activation
Authors: Werner Helmut
Published: May 2010

The activation of a single sp3 CH bond of alkanes and their derivatives by electron‐rich transition metal complexes has been a topic of interest since the landmark work by Bergman and Graham in 1982. Ten years later, it was shown that compounds of 5d elements, such as osmium and iridium, even enable a double α‐CH bond activation of alkane or cycloalkane derivatives containing an OR or NR2 functional group, thus opening up a new route to obtain Fischer‐type transition metal carbene complexes. Subsequent work focused in particular on the conversion of methyl alkyl and methyl aryl ethers into bound oxocarbenes and also of dimethyl amines to bound aminocarbenes. In the context of this work, it was recently shown that square‐planar oxocarbene–iridium(I) complexes prepared in this way exhibit an unusual mode of reactivity: They react with CO2, CS2, COS, PhNCO, and PhNCS by an atom‐ or group‐transfer metathesis, which has no precedent. Organic azides RN3 and N2O behave similarly. Recent results confirm that this novel type of metathesis can be made catalytic, thus offering a novel possibility for CH bond functionalization.
Effects of curing systems and polysulfonamide pulp on the curing characteristics, mechanical properties, and swelling behavior of ethylene–propylene–diene elastomer composites
Authors: Jia Xiaolong , Yu Yunhua , Li Gang , Sui Gang , Li Peng , Yang Xiaoping
Published: May 2010

The effects of three curing systems and polysulfonamide (PSA) pulp on the curing characteristics, mechanical properties, and swelling behavior of ethylene–propylene–diene elastomer (EPDM) composites were investigated. The maximum torque value and the optimum curing time were highest for EPDM composites cured with a peroxide system, and they were closely followed by those cured with a sulfur system. In comparison with those cured with peroxide and phenolic resin systems, EPDM composites cured with the sulfur system showed higher mechanical properties and dimensional stability. With increasing PSA pulp content, the maximum torque value of the EPDM composites increased, whereas the optimum curing time of the composites decreased. The orientation percentage of the PSA pulp in the EPDM composites was maximum at 30 phr pulp, as determined from green strength measurements. In the longitudinal direction along which the pulp was oriented, the EPDM composites showed higher tensile strength as well as lower elongation and swelling ratios. Also, with increasing PSA pulp content, the tensile strength of the EPDM composites decreased up to 10 phr pulp and subsequently increased, whereas the elongation and swelling ratio of the EPDM composites decreased linearly. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Flexibility improvement of poly(lactic acid) by stearate‐modified layered double hydroxide
Authors: Mahboobeh Eili , Yunus Wan Md Zin Wan , Hussein Zobir , Ahmad Mansor , Ibrahim Nor Azowa
Published: May 2010

Poly(lactic acid)/layered double hydroxide (PLA/LDH) nanocomposites were prepared from PLA and stearate‐Mg3Al LDH via a solution casting method. The anionic clay Mg3Al LDH was prepared first by coprecipitation method from nitrate salts solution at pH 9 and then modified by stearate anions through an ion exchange reaction. This modification increased the basal spacing of the synthetic clay from 8.72 to 31.68 Å. The presence of stearate ions in the synthesized Mg3Al LDH was shown by the stearate‐Mg3Al LDH infrared spectrum. When the stearate‐Mg3Al LDH at the low concentration was dispersed in the PLA matrix, its layers were largely delaminated. The presence of 1.0 wt % of the stearate‐Mg3Al LDH in the PLA improved drastically (of around 650%) of its elongation at break but retained its tensile strength and modulus as compared to those of the pure PLA. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Big Macs and Eigenfactor scores: Don't let correlation coefficients fool you
Authors: West Jevin , Bergstrom Theodore , Bergstrom Carl T.
Published: May 2010

The Eigenfactor™ Metrics provide an alternative way of evaluating scholarly journals based on an iterative ranking procedure analogous to Google's PageRank algorithm. These metrics have recently been adopted by Thomson Reuters and are listed alongside the Impact Factor in the Journal Citation Reports. But do these metrics differ sufficiently so as to be a useful addition to the bibliometric toolbox? Davis (2008) has argued that they do not, based on his finding of a 0.95 correlation coefficient between Eigenfactor score and Total Citations for a sample of journals in the field of medicine. This conclusion is mistaken; in this article, we illustrate the basic statistical fallacy to which Davis succumbed. We provide a complete analysis of the 2006 Journal Citation Reports and demonstrate that there are statistically and economically significant differences between the information provided by the Eigenfactor Metrics and that provided by Impact Factor and Total Citations.
Rosette‐Shaped Calcite Structures at Surfaces: Mechanistic Implications for CaCO3 Crystallization
Authors: Yang Sung Ho , Choi Insung S.
Published: May 2010

Biomineralization is believed to be achieved by the intimate cooperation of soluble macromolecules and an insoluble matrix at the specific inorganic–organic interface. It has been reported that positively charged matrices play an important role in controlling the structure of CaCO3 at surfaces, although detailed mechanisms remain unclear. In this work, we studied the transformation from amorphous CaCO3 to calcite crystals on surfaces by using thin films of poly(2‐(dimethylamino)ethyl methacrylate) (PDMAEMA) and its quaternized form. The positively charged PDMAEMA film was found to possess unique properties for CaCO3 crystallization: individually separated, single calcite crystals were formed on the PDMAEMA film in the absence of poly(acrylic acid) (PAA), while circularly fused calcite crystals were formed in the presence of PAA. The circularly fused (rosette‐shaped) calcite crystals could be changed from a completely packed rosette to a ring‐shaped, hollow structure by tuning the crystallization conditions. A number of factors, such as reaction time, amount of (NH4)2CO3, concentration of PAA, and charge of matrix‐films, were varied systematically, and we now propose a mechanism based on these observations.
Serum starvation improves transient transfection efficiency in differentiating embryonic stem cells
Authors: Wallenstein Eric J. , Barminko Jeffrey , Schloss Rene S. , Yarmush Martin L.
Published: May 2010

Control of genetic expression is a critical issue in the field of stem cell biology, where determining a cell fate or reprogramming adult somatic cells into pluripotent cells has become a common experimental practice. In turn, for these cells to have therapeutic clinical potential, techniques for controlling gene expression are needed that minimizes or eliminates the risk of oncogenesis and mutagenesis. Possible routes for achieving this outcome could come in the form of a transient nonviral gene delivery system. In this study, we improved the efficiency of transient gene delivery to differentiating murine embryonic stem (ES) cells via serum starvation for 3 days before transfection. The transient expression of a constitutively‐controlled plasmid increased from ∼50% (replated control) to ∼83% when transfected after 3 days of serum starvation but decreased to ∼28% when transfected after 3 days in normal high serum‐containing media. When probed with a liver‐specific reporter, Cyp7A1, expression increased from ∼1.4% (replated control) to ∼3.7% when transfected after 3 days of serum starvation but decreased to ∼0.7% when transfected after 3 days in high serum‐containing media. Cy3‐tagged oligonucleotides were used to rapidly quantify DNA uptake and predict ultimate transfection efficiency. This study suggests that modifications in media serum levels before transfection can have a profound effect on improving nonviral gene delivery. © 2010 American Institute of Chemical Engineers Biotechnol. Prog., 2010
Preorganized, Macromolecular, Gene‐Delivery Systems
Authors: Ortiz Mellet Carmen , Benito Juan M. , García Fernández José M.
Published: May 2010

Viruses represent a paradigmatic example of multicomponent, self‐organized supramolecular systems specialized in the delivery and replication of their genetic material. Mimicking their functioning by artificial synthetic molecules represents a fantastic challenge that will lead to the future development of gene therapy. This is only possible if general approaches towards the construction of nanoscale vehicles for DNA are developed and the key rules governing their capacity to compact genetic material and its active transport/delivery through cell membranes are understood. In this area of research, synthetic organic chemistry plays an important role by providing tools to create tailor‐made molecules of increasing complexity. Preorganization of functional elements onto macromolecular platforms has the potential to allow control of the self‐assembling behavior of discrete architectures to produce nanometric objects that can be programmed to complex, compact, deliver, and release plasmid DNA in a target cell.
ChemInform Abstract: Synthesis, Characterization, and Photophysical Properties of a Series of Supramolecular Mixed‐Valence Compounds.
Authors: Pfennig Brian W. , Fritchman Virginia A. , Hayman Katie A.
Published: May 2010

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Ni(II)‐Doped CsCdBrCl2: Variation of Spectral and Structural Properties via Mixed‐Halide Coordination.
Authors: Luethi S. R. , Riley M. J.
Published: May 2010

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Electronic Fine Tuning of the Structures of Reduced Rare‐Earth Metal Halides.
Authors: Koeckerling Martin , Martin James D.
Published: May 2010

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Synthesis, Structural Characterization and Magnetic Properties of LnCrO4 Oxides, Ln: Nd, Sm, Eu and Lu.
Authors: Jimenez E. , Isasi J. , Saez‐Puche R.
Published: May 2010

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Resistivity Changes During Hydrogenation of Pd80Ag20 Alloy in Non‐equilibrium Circumstances.
Authors: Toth J. , Garaguly J. , Peter L. , Tompa K.
Published: May 2010

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Magnetic Properties of the LnCo3Sn (Ln: Gd to Tm) Compounds.
Authors: Mudryk J. , Fruchart D. , Gignoux D. , Romaka L. P. , Skolozdra R. V.
Published: May 2010

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Crystallographic, Magnetic and Magnetocaloric Properties of GdMgX Intermetallic Phases (X: Al, Ga, In).
Authors: Canepa F. , Fornasini M. L. , Merlo F. , Napoletano M. , Pani M.
Published: May 2010

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Evidence for a Lower Enthalpy of Formation of Hydroxyl Radical and a Lower Gas‐Phase Bond Dissociation Energy of Water.
Authors: Ruscic Branko , Feller David , Dixon David A. , Peterson Kirk A. , Harding Lawrence B. , Asher Robert L. , Wagner Albert F.
Published: May 2010

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: The Ternary System Sm2O3—SrO—CuO: Compounds and Phase Relations.
Authors: Han C. Q. , Chen X. L. , Liang J. K. , Liu Q. L. , Rao G. H.
Published: May 2010

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: The Isothermal Section of the Phase Diagram of the La—Ni—Ti Ternary System at 673 K.
Authors: Jingqi Liu , Ke Geng
Published: May 2010

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Synthesis and Photochemical Properties of Cd0.8Zn0.2S Pillared H1‐xCa2‐xLaxNb3O10.
Authors: Fukugami Yasuhiko , Sato Tsugio
Published: May 2010

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Crystal Structure of Metastable ϰ‐CeZrO4 Phase Possessing an Ordered Arrangement of Ce and Zr Ions.
Authors: Kishimoto Haruo , Omata Takahisa , Otsuka‐Yao‐Matsuo Shinya , Ueda Kazushige , Hosono Hideo , Kawazoe Hiroshi
Published: May 2010

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Co‐Catalyst Dependent Cycloisomerization or Ring Closing Metathesis of α,ω‐Dienes Catalyzed by Arene Ruthenium Complex with Side‐Arm Alcohol.
Authors: Miyaki Yoshiharu , Onishi Takafumi , Ogoshi Sensuke , Kurosawa Hideo
Published: May 2010

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Synthesis and X‐Ray Structure of Metalated Rhodium(II) Catalysts with a Chiral Phospholane.
Authors: Estevan Francisco , Krueger Peter , Lahuerta Pascual , Moreno Eduardo , Perez‐Prieto Julia , Sanau Mercedes , Werner Helmut
Published: May 2010

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Kinetic Resolution of Amines by a Nonenzymatic Acylation Catalyst.
Authors: Arai Shigeru , Bellemin‐Laponnaz Stephane , Fu Gregory C.
Published: May 2010

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Asymmetric Molybdenum(0)‐Catalyzed Allylic Substitution.
Authors: Malkov Andrei V. , Spoor Paul , Vinader Victoria , Kocovsky Pavel
Published: May 2010

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Syntheses with Organoboranes. Part 11. Allylboration of Vinylic Epoxides with Allylic Dialkylboranes.
Authors: Zaidlewicz Marek , Krzeminski Marek P.
Published: May 2010

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.