bluuebunny/crossref_metadata_2025 huggingface dataset:
CCN activity and volatility of β-caryophyllene secondary organic aerosol
Authors: Frosch M. , Bilde M. , Nenes A. , Praplan A. P. , Jurányi Z. , Dommen J. , Gysel M. , Weingartner E. , Baltensperger U.
Published: August 2012

Abstract. In a series of smog chamber experiments, the Cloud Condensation Nuclei (CCN) activity of Secondary Organic Aerosol (SOA) generated from ozonolysis of β-caryophyllene was characterized by determining the CCN derived hygroscopicity parameter, κCCN, from experimental data. Two types of CCN counters, operating at different temperatures, were used. The effect of semi-volatile organic compounds on the CCN activity of SOA was studied using a thermodenuder. Overall, SOA was only slightly CCN active (with κCCN in the range 0.001–0.16), and in dark experiments with no OH scavenger present, κCCN decreased when particles were sent through the thermodenuder (with a temperature up to 50 °C). SOA was generated under different experimental conditions: in some experiments, an OH scavenger (2-butanol) was added. SOA from these experiments was less CCN active than SOA produced in experiments without an OH scavenger (i.e. where OH was produced during ozonolysis). In other experiments, lights were turned on, either without or with the addition of HONO (OH source). This led to the formation of more CCN active SOA. SOA was aged up to 30 h through exposure to ozone and (in experiments with no OH scavenger present) to OH. In all experiments, the derived κCCN consistently increased with time after initial injection of β-caryophyllene, showing that chemical ageing increases the CCN activity of β-caryophyllene SOA. κCCN was also observed to depend on supersaturation, which was explained either as an evaporation artifact from semi-volatile SOA (only observed in experiments lacking light exposure) or, alternatively, by effects related to chemical composition depending on dry particle size. Using the method of Threshold Droplet Growth Analysis it was also concluded that the activation kinetics of the SOA do not differ significantly from calibration ammonium sulphate aerosol.
Novel method for fog monitoring using cellular networks infrastructures
Authors: David N. , Alpert P. , Messer H.
Published: August 2012

Abstract. A major detrimental effect of fog is visibility limitation which can result in serious transportation accidents, traffic delays and therefore economic damage. Existing monitoring techniques including satellites, transmissometers and human observers – suffer from low spatial resolution, high cost or lack of precision when measuring near ground level. Here we show a novel technique for fog monitoring using wireless communication systems. Communication networks widely deploy commercial microwave links across the terrain at ground level. Operating at frequencies of tens of GHz they are affected by fog and are, effectively, an existing, spatially world-wide distributed sensor network that can provide crucial information about fog concentration and visibility. Fog monitoring potential is demonstrated for a heavy fog event that took place in Israel. The correlation between transmissomters and human eye observations to the visibility estimates from the nearby microwave links was found to be 0.53 and 0.61, respectively. These values indicate the high potential of the proposed method.
Solar Backscatter UV (SBUV) total ozone and profile algorithm
Authors: Bhartia P. K. , McPeters R. D. , Flynn L. E. , Taylor S. , Kramrova N. A. , Frith S. , Fisher B. , DeLand M.
Published: August 2012

Abstract. We describe the algorithm that has been applied to develop a 41 yr time series of total ozone and ozone profiles from eight solar-backscatter UV (sbuv) instruments launched on NASA and NOAA satellites since April 1970. Although the basic algorithm is similar to the V8 algorithm that was released about a decade ago and has been in use since then at NOAA, the details of the V8 algorithm have never been published. The current version (V8.6) incorporates several changes including the use of new ozone absorption cross-sections and new ozone and cloud height climatologies. A particular emphasis in this paper is on characterizing the sources of errors that are relevant for deriving trends from monthly mean anomalies and for estimating biases between different types of ozone sensors. We show that variations in the local time of the measurement due to drifting NOAA satellite orbits can complicate the analysis of trends in the upper stratosphere. Such variations not only increase instrumental and algorithmic uncertainties but also require correction for true local time variations of ozone in the upper stratosphere and lower mesosphere for trend analysis. We find that the monthly zonal anomalies derived from the SBUV data have high precision, sufficient to track year-to-year changes in ozone over a broad range of altitudes. However, because of poor vertical resolution the data are less well suited to track short-term variability of ozone at lower altitudes.
Chorus wave-normal statistics in the Earth's radiation belts from ray tracing technique
Authors: Breuillard H. , Zaliznyak Y. , Krasnoselskikh V. , Agapitov O. , Artemyev A. , Rolland G.
Published: August 2012

Abstract. Discrete ELF/VLF (Extremely Low Frequency/Very Low Frequency) chorus emissions are one of the most intense electromagnetic plasma waves observed in radiation belts and in the outer terrestrial magnetosphere. These waves play a crucial role in the dynamics of radiation belts, and are responsible for the loss and the acceleration of energetic electrons. The objective of our study is to reconstruct the realistic distribution of chorus wave-normals in radiation belts for all magnetic latitudes. To achieve this aim, the data from the electric and magnetic field measurements onboard Cluster satellite are used to determine the wave-vector distribution of the chorus signal around the equator region. Then the propagation of such a wave packet is modeled using three-dimensional ray tracing technique, which employs K. Rönnmark's WHAMP to solve hot plasma dispersion relation along the wave packet trajectory. The observed chorus wave distributions close to waves source are first fitted to form the initial conditions which then propagate numerically through the inner magnetosphere in the frame of the WKB approximation. Ray tracing technique allows one to reconstruct wave packet properties (electric and magnetic fields, width of the wave packet in k-space, etc.) along the propagation path. The calculations show the spatial spreading of the signal energy due to propagation in the inhomogeneous and anisotropic magnetized plasma. Comparison of wave-normal distribution obtained from ray tracing technique with Cluster observations up to 40° latitude demonstrates the reliability of our approach and applied numerical schemes.
Vegetation history of central Chukotka deduced from permafrost paleoenvironmental records of the El'gygytgyn Impact Crater
Authors: Andreev A. A. , Morozova E. , Fedorov G. , Schirrmeister L. , Bobrov A. A. , Kienast F. , Schwamborn G.
Published: August 2012

Abstract. Frozen sediments from three cores bored in the permafrost surrounding the El'gygytgyn Impact Crater Lake have been studied for pollen, non-pollen palynomorphs, plant macrofossils and rhizopods. The palynological study of these cores contributes to a higher resolution of time intervals presented in a poor temporal resolution in the lacustrine sediments; namely the Allerød and succeeding periods. Moreover, the permafrost records better reflect local environmental changes, allowing a more reliable reconstruction of the local paleoenvironments. The new data confirm that shrub tundra with dwarf birch, shrub alder and willow dominated the lake surroundings during the Allerød warming. Younger Dryas pollen assemblages reflect abrupt changes to grass-sedge-herb dominated environments reflecting significantly drier and cooler climate. Low shrub tundra with dwarf birch and willow dominate the lake vicinity at the onset of the Holocene. The find of larch seeds indicate its local presence around 11 000 cal yr BP and, thus a northward shift of treeline by about 100 km during the early Holocene thermal optimum. Forest tundra with larch and shrub alder stands grew in the area during the early Holocene. After ca. 3500 cal yr BP similar-to-modern plant communities became common in the lake vicinity.
Pre-industrial and mid-Pliocene simulations with NorESM-L: AGCM simulations
Authors: Zhang Z. , Yan Q.
Published: August 2012

Abstract. In the Pliocene Model Intercomparison Project (PlioMIP), two sets of experiments are suggested. One includes a reference and a mid-Pliocene experiment run with atmosphere general circulation models (AGCM experiments, referred to as Experiments I), the other includes a pre-industrial and a mid-Pliocene experiment run with coupled ocean-atmosphere general circulation models (AOGCM experiments, referred to as Experiments II). In this paper, we describe the AGCM experiments with the atmosphere component in the low-resolution version of the Norwegian Earth System Model (NorESM-L), and also assess the potential uncertainties in analyzing mid-Pliocene climate anomalies that might result from the choice of the sea surface temperature (SST) forcing for the reference experiment (pre-industrial or modern). We carry out a mid-Pliocene experiment, a control experiment forced by the modern SST fields, and a pre-industrial experiment forced by the monthly SST fields from HadISST averaged between 1879 and 1900. Our experiments illustrate that the simulated mid-Pliocene global mean annual surface air temperature (SAT) is 17.1 °C. It is 2.5 °C warmer than the control experiment, but 2.7 °C warmer than the pre-industrial experiment. We find that the uncertainties in analyses of mid-Pliocene climate anomalies are small on a global scale, but still large on a regional scale. On the regional scale, these uncertainties should be noted and assessed in future PlioMIP studies.
Value of medium range weather forecasts in the improvement of seasonal hydrologic prediction skill
Authors: Shukla S. , Voisin N. , Lettenmaier D. P.
Published: August 2012

Abstract. We investigated the contribution of medium range weather forecasts with lead times of up to 14 days to seasonal hydrologic prediction skill over the conterminous United States (CONUS). Three different Ensemble Streamflow Prediction (ESP) based experiments were performed for the period 1980–2003 using the Variable Infiltration Capacity (VIC) hydrology model to generate forecasts of monthly runoff and soil moisture (SM) at lead-1 (first month of the forecast period) to lead-3. The first experiment (ESP) used a resampling from the retrospective period 1980–2003 and represented full climatological uncertainty for the entire forecast period. In the second and third experiments, the first 14 days of each ESP ensemble member were replaced by either observations (perfect 14-day forecast) or by a deterministic 14-day weather forecast. We used Spearman rank correlations of forecasts and observations as the forecast skill score. We estimated the potential and actual improvement in baseline skill as the difference between the skill of experiments 2 and 3 relative to ESP, respectively. We found that useful runoff and SM forecast skill at lead-1 to -3 months can be obtained by exploiting medium range weather forecast skill in conjunction with the skill derived by the knowledge of initial hydrologic conditions. Potential improvement in baseline skill by using medium range weather forecasts for runoff [SM] forecasts generally varies from 0 to 0.8 [0 to 0.5] as measured by differences in correlations, with actual improvement generally from 0 to 0.8 of the potential improvement. With some exceptions, most of the improvement in runoff is for lead-1 forecasts, although some improvement in SM was achieved at lead-2.
Impacts of impervious cover, water withdrawals, and climate change on river flows in the conterminous US
Authors: Caldwell P. V. , Sun G. , McNulty S. G. , Cohen E. C. , Moore Myers J. A.
Published: August 2012

Abstract. Rivers are essential to aquatic ecosystem and societal sustainability, but are increasingly impacted by water withdrawals, land-use change, and climate change. The relative and cumulative effects of these stressors on continental river flows are relatively unknown. In this study, we used an integrated water balance and flow routing model to evaluate the impacts of impervious cover and water withdrawal on river flow across the conterminous US at the 8-digit Hydrologic Unit Code (HUC) watershed scale. We then estimated the impacts of projected change in withdrawals, impervious cover, and climate under the B1 "Low" and A2 "High" emission scenarios on river flows by 2060. Our results suggest that compared to no impervious cover, 2010 levels of impervious cover increased river flows by 9.9% on average with larger impacts in and downstream of major metropolitan areas. In contrast, compared to no water withdrawals, 2005 withdrawals decreased river flows by 1.4% on average with larger impacts in heavily irrigated arid regions of Western US. By 2060, impacts of climate change were predicted to overwhelm the potential gain in river flow due to future changes in impervious cover and add to the potential reduction in river flows from withdrawals, decreasing mean annual river flows from 2010 levels by 16% on average. However, increases in impervious cover by 2060 may offset the impact of climate change during the growing season in some watersheds. Large water withdrawals will aggravate the predicted impact of climate change on river flows, particularly in the Western US. Predicted ecohydrological impacts of land cover, water withdrawal, and climate change will likely include alteration of the terrestrial water balance, stream channel habitat, riparian and aquatic community structure in snow-dominated basins, and fish and mussel extirpations in heavily impacted watersheds. These changes may also require new infrastructure to support increasing anthropogenic demand for water, relocation of agricultural production, and/or water conservation measures. Given that the impacts of land use, withdrawals and climate may be either additive or offsetting in different magnitudes, integrated and spatially explicit modeling and management approaches are necessary to effectively manage water resources for aquatic life and human use in the face of global change.
Submarine mass wasting and associated tsunami risk offshore western Thailand, Andaman Sea, Indian Ocean
Authors: Schwab J. M. , Krastel S. , Grün M. , Gross F. , Pananont P. , Jintasaeranee P. , Bunsomboonsakul S. , Weinrebe W. , Winkelmann D.
Published: August 2012

Abstract. 2-D seismic data from the top and the western slope of Mergui Ridge in water depths between 300 and 2200 m off the Thai west coast have been investigated in order to identify mass transport deposits (MTDs) and evaluate the tsunamigenic potential of submarine landslides in this outer shelf area. Based on our newly collected data, 17 mass transport deposits have been identified. Minimum volumes of individual MTDs range between 0.3 km3 and 14 km3. Landslide deposits have been identified in three different settings: (i) stacked MTDs within disturbed and faulted basin sediments at the transition of the East Andaman Basin to the Mergui Ridge; (ii) MTDs within a pile of drift sediments at the basin-ridge transition; and (iii) MTDs near the edge of/on top of Mergui Ridge in relatively shallow water depths (< 1000 m). Our data indicate that the Mergui Ridge slope area seems to have been generally unstable with repeated occurrence of slide events. We find that the most likely causes for slope instabilities may be the presence of unstable drift sediments, excess pore pressure, and active tectonics. Most MTDs are located in large water depths (> 1000 m) and/or comprise small volumes suggesting a small tsunami potential. Moreover, the recurrence rates of failure events seem to be low. Some MTDs with tsunami potential, however, have been identified on top of Mergui Ridge. Mass-wasting events that may occur in the future at similar locations may trigger tsunamis if they comprise sufficient volumes. Landslide tsunamis, emerging from slope failures in the working area and affecting western Thailand coastal areas therefore cannot be excluded, though the probability is very small compared to the probability of earthquake-triggered tsunamis, arising from the Sunda Trench.
Seismicity from February 2006 to September 2007 at the Rwenzori Mountains, East African Rift: earthquake distribution, magnitudes and source mechanisms
Authors: Lindenfeld M. , Rümpker G. , Batte A. , Schumann A.
Published: August 2012

Abstract. We have analysed the microseismic activity within the Rwenzori Mountains area in the western branch of the East African Rift. Seismogram recordings from a temporary array of up to 27 stations reveal approximately 800 events per month with local magnitudes ranging from –0.5 to 5.1. The earthquake distribution is highly heterogeneous. The majority of located events lie within faults zones to the east and west of the Rwenzoris with the highest seismic activity observed in the northeastern area, where the mountains are in contact with the rift shoulders. The hypocentral depth distribution exhibits a pronounced peak of seismic energy release at 15 km depth. The maximum extent of seismicity ranges from 20 to 32 km and correlates well with Moho depths that were derived from teleseismic receiver functions. We observe two general features: (i) beneath the rift shoulders, seismicity extends from the surface down to ca. 30 km depth; (ii) beneath the rift valley, seismicity is confined to depths greater than 10 km. From the observations there is no indication for a crustal root beneath the Rwenzori Mountains. The magnitude frequency distribution reveals a b-value of 1.1, which is consistent with the hypothesis that part of the seismicity is caused by magmatic processes within the crust. Fault plane solutions of 304 events were derived from P-polarities and SV/P amplitude ratios. More than 70 % of the source mechanisms exhibit pure or predominantly normal faulting. T-axis trends are highly uniform and oriented WNW–ESE, which is perpendicular to the rift axis and in good agreement with kinematic rift models. At the northernmost part of the region we observe a rotation of the T-axis trends to NEN–SWS, which may be indicative of a local perturbation of the regional stress field.
Polycyclic Aromatic Hydrocarbons and Azaaromatic Compounds
Authors: Baxter C. Stuart , Warshawsky David
Published: August 2012

Polycyclic aromatic hydrocarbons (PAHs) are moderately reactive, but undergo photochemical degradation in the atmosphere, and are widely used as chemical raw materials. Aromatic hydrocarbons cause local irritation and changes in endothelial cell permeability and are absorbed rapidly. Accumulation of aromatic hydrocarbons in marine animals occurs to a greater extent and retention is longer compared to alkanes. Toxicity of polynuclear aromatics has been reported comprehensively. It has been reported that exposure to a variety of complex mixtures containing these chemicals, such as soot, coal tar and pitch, mineral oils, coal gasification residues, and cigarette smoke has historically been associated with induction of cancer. Naphthalene causes cataracts in the eyes of experimental animals. Its vapors may cause severe systemic injury. Alkylbenzenes are readily aspirated and produce instant death via cardiac arrest and respiratory paralysis. In general, the acute toxicity of alkylbenzenes is higher for toluene than that for benzene and decreases further with increasing chain length of the substituent, except for highly branched C8to C18derivatives. Polycyclic aromatic hydrocarbons are metabolized through epoxides and hydroxides and are excreted as conjugates.
Aliphatic and Aromatic Nitrogen Compounds
Authors: Jr. Kennedy Gerald L.
Published: August 2012

This chapter covers both aliphatic and aromatic compounds that contain one or more nitrogen atoms in their structures. Only a small number of the nitrogen‐containing compounds that could be considered will be reviewed here mainly based on their uses in industry. This is an update of a previous chapter and for each chemical, the first sentence will tell the reader whether there has been significant new information published in the literature and included or whether there has been little or no new information available for update and inclusion.

Three‐membered rings discussed are ethyleneimine, propyleneimine, and, one polyfunctional derivative, triethylenemelamine. Toxicologists, chemists, and biologists have always been interested in ethyleneimine and its derivatives because they are reactive, are useful at relatively low doses, and are moderately to highly toxic. Ethyleneimines are classic alkylating agents and have toxicological effects similar to nitrogen mustards. Monofunctional derivatives of ethyleneimine are less potent in producing the characteristic toxicity of the group than the derivatives that have two or more ethyleneimine groups. Finally, polymers of ethyleneimine and its derivatives have shown a relatively low order of toxicity.

Six simple nitrogen mustards (β‐chloroethylamines) are also covered in this chapter. They are all tertiary amines in which the halogen atom and the amine portion have reactivities similar to the alkyl halides and alkyl amines. They have no significant industrial uses in the United States, but they are used in medicine as “antineoplastic agents” and in treating some nonmalignant diseases.

Representative nitrogen‐containing chemicals that have five‐membered rings (pyrrolidine,N‐methyl‐2‐pyrrolidinone) and six‐membered rings (piperidine, piperazine, morpholine, and hexamethylenetetramine) are also discussed in this chapter in some detail.

Several representative aromatic nitrogen compounds are covered—pyrrole, aminotriazole,N‐sulfenyl phthalimide fungicides, benzimidazole fungicides, and 1‐H‐benzotriazole. The data presented for compounds of this class that are used in agriculture include toxicology studies that have been published in the open literature as well as those available through company files to support governmental registration.

In some cases, the high toxicity of the agent has been considered and is the reason for its inclusion here, rather than usage volume or industrial importance. Further, very little pharmacological information is presented because this is adequately covered in the pharmacological literature. We have tried to minimize hypotheses regarding the mechanism of action not because it is unimportant, but because the biochemistries are often very detailed, are almost always fairly speculative, and are presented comprehensively in other texts. Likewise, we resisted the temptation to employ structure–activity relationships because, although the database is very thorough for some chemicals, it did not contain enough analogous chemicals with known, comparable toxicity profiles.
Ethers of Ethylene Glycol and Derivatives
Authors: Cragg Steven T.
Published: August 2012

There are seven U.S. manufacturers of ethers and other derivatives of ethylene glycol (EG), diethylene glycol (DEG), and higher glycols. Five of them are members of the American Chemistry Council (ACC) Glycol Ethers' Panel.

The glycol ethers most commonly encountered industrially are colorless liquids that have mild ethereal odors. Alkyl glycol ethers are manufactured in a closed, continuous process by reacting ethylene oxide with an anhydrous alcohol in the presence of a suitable catalyst. Depending on the molar ratios of the reactants and other process parameters, the product mixtures obtained contain varying amounts of the monoethylene, diethylene, triethylene, and higher glycol ethers. Typically, the products in these mixtures are separated and purified by fractional distillation.

The miscibility of most of these ethers with water and with a large number of organic solvents makes them especially useful as solvents in oil–water compositions. Their relatively slow rate of evaporation also makes them useful as solvents and coalescing agents in paints. Other uses include inks, cleaners, chemical intermediates, process solvents, brake fluids, and deicers. The ethers of the higher glycols are used as hydraulic fluids. An estimate of the U.S. production and use of representative ethylene glycol ethers is presented. Production of ethylene glycol ethers (total) in Western Europe amounted to 245 thousand metric tons in 1995.

Occupational exposure to glycol ethers occurs dermally and by inhalation. Ingestion is not a concern in industrial exposure, although some cases of intentional ingestion of consumer products containing ethylene glycol ethers have been reported.

A number of analytical methods have been published that are suitable for detecting glycol ethers in environmental air samples.

Glycol ethers generally have low acute, single‐dose toxicity, and LD50values generally range from 1.0 to 4.0 g/kg of body weight. In animals and humans, high‐dose administrations (>350 mg/kg) result in central nervous system (CNS) depression, although the results from many studies show no specific damage to neural tissues. Other toxicological effects attributable to glycol ethers are associated with metabolism to the corresponding alkoxyacetic acids. In the case of EGME, EGEE, and certain other glycol ether derivatives, significant reproductive, developmental, hematologic, and immunologic effects have been associated with the formation of either methoxyacetic acid (MAA) or ethoxyacetic acids (EAA). For other glycol ether derivatives substituted with propyl, butyl, or higher homologues, both developmental effects secondary to maternal toxicity (without teratogenic effects) and hematologic effects are observed.

Ethylene glycol ethers and acetates may enter the environment from manufacturing effluents and emissions and as a result of their use in commercial products.
Carbon Black
Authors: McCunney Robert J. , Muranko Henry J. , Long Chris M. , Hamade Ali K. , Valberg Peter A. , Morfeld Peter
Published: August 2012

Carbon black is a powdered form of elemental carbon, obtained by partial combustion or thermal decomposition of hydrocarbons. It is a member of the class of substances known as industrial aciniform aggregates (IAA). Carbon black can be released to the ambient environment during the manufacturing process, and it thus can be a component of airborne particulate matter (PM) in the vicinity of carbon black manufacturing plants and user industries. Carbon black production in Asia has experienced substantial growth in the past decade. Today over 95% of carbon black worldwide is produced by the oil furnace process. The potential health implications of occupational exposure to carbon black have been addressed primarily in cohort mortality and cross‐sectional morbidity studies among workers who manufacture carbon black. Carbon black has gained usage as a model particle in particle toxicology investigations, with extensive study in bothin vivoandin vitrolaboratory experiment. The particle size characteristics of manufactured carbon blacks have been extensively studied and found that inhalable airborne carbon black particles are significantly larger in aerodynamic diameter than particles that occur in the early stages of carbon black formation. The scientific evidence of the potential carcinogenicity of carbon black are described extending the current evaluation given by IARC. A number of health‐based air quality standards have been developed for airborne PM and carbon black. Occupational exposure limits (OELs) for carbon black are presented and discussed.
Toxicology of Flavors in the Food Industry
Authors: Doepker Candace L. , Maier Andrew , Willis, B.S Alison , Hermansky Steven J.
Published: August 2012

The present chapter represents toxicological information on selected flavoring ingredients commonly found in the food and beverage workplace that have recently gathered attention regarding potential risks to the workers handling them. GRAS ingredients can present hazards in the occupational context, it is very important that workers review material safety data sheets (MSDS) and understand the verbiage on these MSDS as part of a comprehensive hazard communication program. FEMA and the Joint FAO/WHO Expert Committee on Food Additives (JECFA) have adopted modified Cramer approaches and the TTC concept to classify flavor ingredients by structure and, thus, according to risk. Today, new chemical entities are being designed and created to maximize and/or customize the interaction of the flavor ingredient with taste receptors. Several important flavor chemicals have been covered in this chapter with respect to their properties, exposure assessment, toxicity, and regulations of exposure.
A 4‐Amino‐1,8‐Naphthalimide Derivative for Selective Fluorescent Detection of Palladium(II) Ions
Authors: Wang Changcheng , Zheng Xiaolong , Huang Rong , Yan Shengyong , Xie Xia , Tian Tian , Huang Shiwen , Weng Xiaocheng , Zhou Xiang
Published: August 2012

Palladium is a member of the platinum group of metals and can be used in the electronics industry for applications such as preparing precision resistors. It is also utilized for catalysis in organic chemistry to achieve faster reaction speeds and lower costs of production in industry. Overexposure to Pd is harmful to the environment and to human health because it can be conveyed quickly to the liver, kidney, spleen, adrenal glands, lungs, and bones. Herein, a fluorescent probe that contains an alkynyl group for specific reaction with PdII ions, and a naphthalimide group as a fluorophore was designed. This probe has high specificity and selectivity for PdII ions relative to many other metal ions. HPLC analysis was carried out to verify the mechanism of the detection. There is a distinct color change during the detection process. The influence of pH values shows that the probe is suitable to detect PdII ions in the range pH 6–9.
Determination of the critical concentration of partially hydrolyzed polyacrylamide by potentiometry in an acidic medium
Authors: Gomes Marcos P. S. , Costa Marta
Published: August 2012

The literature presents different methods for quantifying and characterizing partially hydrolyzed polyacrylamide (HPAM) in solution. However, only a few of these are suitable for determining the critical overlap concentration (C*). The evaluation of C* is important for describing the transition from the dilute to the semidilute regime, that is, when the solution depicts a characteristic viscosity at concentrations above C*. This article describes the determination of C* for HPAM in solution by potentiometry. The molecular weight, degree of hydrolysis, and polymerization degree are determined by mathematical manipulation of the constant of formation of aggregates, which is based on the law of mass action. The potentiometric curves were initially linear; asymptotic behavior followed. The inflection point was determined by the intersection, and the resulting equation of mathematical development statistically satisfied the experimental data and described the number of moles of monomers, the equilibrium constant for the formation of the aggregate, C*, and the acidity constant of the polymer. The results for C*, the degree of copolymerization, and the molecular weight proved that this method is a good alternative for the characterization of polymers with ionizable monomers and that are soluble in water. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Nanocomposites of ethylene vinyl alcohol copolymer with thermally resistant cellulose nanowhiskers by melt compounding (II): Water barrier and mechanical properties
Authors: Martínez‐Sanz Marta , Lopez‐Rubio Amparo , Lagaron Jose M.
Published: August 2012

In the present work, the crystallinity and crystalline morphology, thermal stability, water barrier, and mechanical properties of ethylene vinyl alcohol copolymer (EVOH) nanocomposites prepared by melt compounding and incorporating both plant (CNW) and bacterial cellulose nanowhiskers (BCNW) are reported. An improvement in the water barrier performance was observed, that is, 67% permeability drop, only for the microcomposite sample incorporating 2 wt % of bacterial cellulose fibrils. No significant differences in the water‐barrier properties of the nanocomposites generated through the two studied preincorporation methods were observed despite the fact that an excellent dispersion was observed in the previous study. On the other hand, direct melt‐mixing of the freeze‐dried nanofiller with EVOH resulted in increased water permeation. The aggregation of the filler in the latter nanocomposite was also ascribed to the detrimental effect on the mechanical properties. Interestingly, by using the precipitation method, an increase in the elastic modulus and tensile strength of ∼36 and 22%, respectively, was observed for a 3 wt % BCNW loading, which was thought to coincide with the percolation threshold. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Stable Sugar‐Chain‐Immobilized Fluorescent Nanoparticles for Probing Lectin and Cells
Authors: Shinchi Hiroyuki , Wakao Masahiro , Nakagawa Sho , Mochizuki Eiko , Kuwabata Susumu , Suda Yasuo
Published: August 2012

Sugar chains are important molecules in cellular recognition and signaling, and quantum dots (QDs) are a very powerful tool for in vitro and in vivo imaging. Herein, we report the preparation of stable sugar‐chain‐immobilized fluorescent nanoparticles (SFNPs) and their application to the analysis of sugar‐chain–protein interactions and cellular imaging. SFNPs were easily prepared by mixing CdTe/CdS core/shell QDs with our previously developed sugar‐chain–ligand conjugates. The obtained SFNPs were very stable and could be stored for several months. In the binding analysis, β‐galactose‐ and α‐glucose‐immobilized SFNPs were specifically interacted with Ricinus communis agglutinin I and concanavalin A, respectively, and made into aggregates. The binding interaction was detected visually, fluorescently, or both. In the experiment for cellular imaging, it was found that SFNPs were predominantly taken up by human hepatocyto carcinoma cells (HepG2), suggesting the possible usage of our designed SFNPs for various biochemical analyses of sugar chains.
Closing the Ring to Bring Up the Light: Synthesis of a Hexacyclic Acridinium Cyanine Dye
Authors: Mahmood Tariq , Wu Yilei , Loriot Domitille , Kuimova Marina , Ladame Sylvain
Published: August 2012

The synthesis of a geometrically constrained and near‐planar hexacyclic acridinium cyanine dye 9 is reported. When compared to its unlocked and non‐fluorescent monomethine cyanine dye analogue 3, this photostable dye emits in the green area of the spectrum with a remarkable quantum yield close to unity in organic solvents and above 0.5 in water. A detailed steady‐state and time‐resolved spectroscopic study revealed that dye 9 forms emissive aggregates in water, which are responsible for a red‐shifted and broadened emission band and longer emission lifetime, τ≈33 compared to 6.5–7.0 ns for the monomeric dye. Dye 9 also binds strongly to DNA (both duplex and quadruplex) in its monomeric form and is very efficiently taken up by cells, in which it accumulates primarily into the nucleus.
Formation of Metal Oxyfluorides from Specific Metal Reactions with Oxygen Difluoride: Infrared Spectroscopic and Theoretical Investigations of the OScF2 Radical and OScF with Terminal Single and Triple ScO Bonds
Authors: Gong Yu , Andrews Lester , Bauschlicher Charles W.
Published: August 2012

The scandium oxydifluoride free radical, OScF2, is produced by the spontaneous, specific reaction of laser ablated Sc atoms with OF2 in solid argon and characterized by using matrix infrared spectroscopy and theoretical calculations. The OScF2 molecule is predicted to have C2v symmetry and a 2B2 ground state with an unpaired electron located primarily on the terminal oxygen atom, which makes it a scandium difluoride molecule coordinated by a neutral oxygen atom radical in forming the ScO single bond. The closed shell singlet OScF molecule with an obtuse bent geometry has a much shorter ScO bond of 1.682 Å than that of the OScF2 radical (1.938 Å) on the basis of B3LYP calculations. The ScO bond in OScF consists of two covalent bonds and a dative bond in which the oxygen 2pπ lone pair donates electron density into an empty Sc 3d orbital thus forming a triple oxo bond. Density functional calculations suggest it is highly exothermic for fluorine transfer from OF2 to scandium, which favors the formation of the OScF2 radical species as well as the OScF molecule after fluorine loss.
Effect on Charge Transfer and Charge Recombination by Insertion of a Naphthalene‐Based Bridge in Molecular Dyads Based on Borondipyrromethene (Bodipy)
Authors: Benniston Andrew C. , Clift Sophie , Hagon Jerry , Lemmetyinen Helge , Tkachenko Nikolai V. , Clegg William , Harrington Ross W.
Published: August 2012

The photophysical properties of two related dyads based on a N,N‐dimethylaniline donor coupled to a fully‐alkylated boron dipyrromethene (Bodipy) acceptor are described. In one dyad, BD1, the donor unit is attached directly to the Bodipy group, whereas in the second dyad, BD2, a naphthalene spacer separates the two units. Cyclic voltammograms recorded for the two dyads in deoxygenated MeCN containing a background electrolyte are consistent with the reversible one‐electron oxidation of the N,N‐dimethylaniline group and the reversible one‐electron reduction of the Bodipy nucleus. There is a reasonable driving force (ΔGCT) for photoinduced charge transfer from the N,N‐dimethylaniline to the Bodipy segment in MeCN. The charge‐transfer state is formed for BD1 extremely fast (1.5 ps), but decays over 140 ps to partially restore the ground state. On the other hand, the charge‐transfer state for BD2 is formed more slowly, but it decays extremely rapidly. Charge recombination for both dyads leads to a partial triplet formation on the Bodipy group. The naphthalene spacer group is extremely efficient at promoting back electron transfer.
Synthesis and Electrocatalytic Properties of Palladium Network Nanostructures
Authors: Zhang Guojie , Zhang Lu , Shen Liping , Chen Yu , Zhou Yiming , Tang Yawen , Lu Tianhong
Published: August 2012

An inorganic polymeric hydrogel, which is formed irreversibly in water through interaction between K2PdIICl4 and K4FeII(CN)6, is synthesized. The palladium nanostructures take the form of three‐dimensional (3D) networks and are obtained in a facile manner by simple reduction of the hydrogel using NaBH4. The size, morphology, and surface composition of these 3D palladium networks are investigated by scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy‐dispersive spectroscopy (EDS), selected‐area electron diffraction (SAED), X‐ray diffraction (XRD), and X‐ray photoelectron spectroscopy (XPS). The electrochemical properties are investigated in detail by cyclic voltammetry, chronoamperometry, and CO stripping tests. Such 3D nanostructures exhibit a large electroactive surface area, excellent electrochemical stability, and high electrocatalytic activity toward electrooxidation of formic acid.
Laminin and integrin expression in the ventral ectodermal ridge of the mouse embryo: Implications for regulation of BMP signalling
Authors: Lopez‐Escobar Beatriz , De Felipe Beatriz , Sanchez‐Alcazar Jose Antonio , Sasaki Takako , Copp Andrew J. , Ybot‐Gonzalez Patricia
Published: August 2012

Background: The ventral ectodermal ridge (VER) is an important signalling centre in the mouse tail‐bud following completion of gastrulation. BMP regulation is essential for VER function, but how these signals are transmitted between adjacent tissues is unclear. Results: We investigated the idea that extracellular matrix components might be involved, using immunohistochemistry and in situ hybridisation to detect all known α, β, and γ laminin chains and their mRNAs in the early tail bud. We identified an apparently novel laminin variant, comprising α5, β3 and γ2 chains, as a major component of the VER basement membrane at E9.5. Strikingly, only the mRNAs for these chains were co‐expressed in VER cells, suggesting that lamin532 may be the sole basement membrane laminin at this stage. Since α6 integrin was also expressed in VER cells, this raises the possibility of cell‐matrix interactions regulating BMP signalling at this site of caudal morphogenesis. Conclusions: Laminin532 could interact with α6‐containing integrin to direct differentiation of the specialised VER cells from surface ectoderm. Developmental Dynamics 241:1808–1815, 2012. © 2012 Wiley Periodicals Inc.
Cdc42 GTPase and Rac1 GTPase act downstream of p120 catenin and require GTP exchange during gastrulation of zebrafish mesoderm
Authors: Hsu Cynthia L. , Muerdter Claire P. , Knickerbocker Abhay D. , Walsh Ryan M. , Zepeda‐Rivera Martha A. , Depner Kevin H. , Sangesland Maya , Cisneros Trinidad B. , Kim Ju Youn , Sanchez‐Vazquez Patricia , Cherezova Lidia , Regan Rainy D. , Bahrami Nadia M. , Gray Elizabeth A. , Chan Andrew Y. , Chen Terry , Rao Milly Y. , Hille Merrill B.
Published: August 2012

Background: We investigated the roles of p120 catenin, Cdc42, Rac1, and RhoA GTPases in regulating migration of presomitic mesoderm cells in zebrafish embryos. p120 catenin has dual roles: It binds the intracellular and juxtamembrane region of cadherins to stabilize cadherin‐mediated adhesion with the aid of RhoA GTPase, and it activates Cdc42 GTPase and Rac1 GTPase in the cytosol to initiate cell motility. Results: During gastrulation of zebrafish embryos, knockdown of the synthesis of zygotic p120 catenin δ1 mRNAs with a splice‐site morpholino caused lateral widening and anterior‐posterior shortening of the presomitic mesoderm and somites and a shortened anterior‐posterior axis. These phenotypes indicate a cell‐migration effect. Co‐injection of low amounts of wild‐type Cdc42 or wild‐type Rac1 or dominant‐negative RhoA mRNAs, but not constitutively‐active Cdc42 mRNA, rescued these p120 catenin δ1‐depleted embryos. Conclusions: These downstream small GTPases require appropriate spatiotemporal stimulation or cycling of GTP to guide mesodermal cell migration. A delicate balance of Rho GTPases and p120 catenin underlies normal development. Developmental Dynamics 241:1545–1561, 2012. © 2012 Wiley Periodicals Inc.
Node‐positive hypopharyngeal cancer treated by (chemo)radiotherapy: Impact of up‐front neck dissection on outcome, toxicity, and quality of life
Authors: Al‐Mamgani Abrahim , Meeuwis Cees A. , van Rooij Peter H. , Mehilal Robert , Basdew Harie , Sewnaik Aniel , Levendag Peter C.
Published: August 2012

Background

To investigate the impact of up‐front neck dissection on the outcome of patients with node‐positive hypopharyngeal cancer (HPC) treated with (chemo)radiation.

Methods

Of 135 consecutive patients with node‐positive HPC, 32 patients underwent up‐front neck dissection followed by (chemo)radiation (group 1), and 103 patients received definitive (chemo)radiation (group 2).

Results

The 3‐year regional, local and distant control for groups 1 and 2 were 92% versus 87% (p = .37), 84% versus 72% (p = .15), and 80% versus 62% (p = .08), respectively. High T classification was the only significant predictor for poor overall survival on multivariate analysis (OR = 3.0, p = .02). Acute and late toxicities and the prospectively assessed quality of life were comparable in both groups.

Conclusion

Upfront neck dissection followed by (chemo)radiation did not negatively impact on oncologic outcomes, toxicity, or quality of life and therefore is to be regarded as a safe and effective treatment option for small HPC with bulky nodal disease, especially in busy radiation departments with unacceptably long waiting time for definitive (chemo)radiation. © 2012 Wiley Periodicals, Inc. Head Neck, 2013
Analysis of risk factors for retropharyngeal lymph node metastasis in carcinoma of the hypopharynx
Authors: Wu Zheng , Deng Xue‐Ying , Zeng Rui‐Fang , Su Yong , Gu Mo‐Fa , Zhang Yun , Xie Chuan‐Miao , Zheng Lie
Published: August 2012

Background

The purpose of this study was to investigate the incidence of retropharyngeal lymph node (RPLN) metastasis and to explore the associated risk factors using CT and MRI, to direct clinical radiotherapy in hypopharyngeal carcinoma (HPC).

Methods

The CT and MRI images of 218 patients with pathologically confirmed HPC were analyzed retrospectively. The chi‐square test and logistic regression were used for statistical analysis.

Results

The incidence of RPLN metastasis in HPC was 17.0%, and the highest rate of 36.4% was found in pharyngeal wall carcinoma. None of the patients with N0 classification exhibited RPLN metastasis. Univariate and multivariate analyses demonstrated that primary tumor subsites, bilateral cervical lymph node metastasis, the number and size of cervical lymph nodes, and level V metastasis were significantly associated with RPLN metastasis.

Conclusions

Our findings demonstrated that primary carcinoma subsites and multiple metastatic cervical lymph nodes are the principal risk factors for RPLN metastasis. © 2012 Wiley Periodicals, Inc. Head Neck, 2013
Effect of intradermal human recombinant copper‐zinc superoxide dismutase on random pattern flaps in rats
Authors: Schein Ophir , Westreich Melvyn , Shalom Avshalom
Published: August 2012

Background

Studies have focused on enhancing flap viability using superoxide dismutase (SOD), but only a few used SOD from human origin, and most gave the compound systemically. We evaluated the ability of SOD to improve random skin flap survival using human recombinant copper‐zinc superoxide dismutase (Hr‐CuZnSOD) in variable doses, injected intradermally into the flap.

Methods

Seventy male Sprague Dawley rats were randomly assigned into 4 groups. Cephalic random pattern flaps were elevated on their backs and intradermal injections of different dosages of Hr‐CuZnSOD were given 15 minutes before surgery. Flap survival was evaluated by fluorescein fluorescence. Analysis of variance (ANOVA) and t test statistical analyses were performed.

Results

Flap survival in all treated groups was significantly better than in the controls.

Conclusions

The beneficial effect of HR‐CuZnSOD on flap survival is attained when it is given intradermally into the flap tissue. Theoretically, Hr‐CuZnSOD delivered with local anesthetics used in flap elevation may be a valuable clinical tool. © 2012 Wiley Periodicals, Inc. Head Neck, 2013