bluuebunny/crossref_metadata_2025 huggingface dataset:
Prevalence of sleep problems in Smith‐Lemli‐Opitz syndrome
Authors: Zarowski Marcin , Vendrame Martina , Irons Mira , Kothare Sanjeev V.
Published: May 2011

Smith‐Lemli‐Opitz syndrome (SLOS) is an autosomal recessive genetic disorder, characterized by multiple congenital anomalies, and intellectual disability. It is caused by a genetically inherited deficiency of the enzyme 7‐dehydrocholesterol‐delta‐7‐reductase, which results in increased serum levels of 7‐dehydrocholesterol (7‐DHC), and decreased levels of cholesterol. This study assesses the prevalence of sleep problems in patients with SLOS. The study group comprised 18 subjects with SLOS, ages 2–31 years (median 10.7 ± 8.5 years). Parents completed several questionnaires (Intake Demographic Form; Pediatric Sleep Questionnaire; Pediatric Daytime Sleepiness Scale). The SLOS subjects had symptoms of sleep‐disordered breathing (50% snoring; 66.7% mouth breathing), problems with sleep onset [difficulty falling asleep (61.1%) sleep onset time >30 min (62%)], sleep maintenance [wake up screaming (61.1%), waking up more than twice (44.4%), having trouble falling back to sleep (66.7%), waking up early in the morning (61.1%), and restless sleep (50%)]. The subjects with SLOS needed parents in the room to fall asleep (50%), watch TV or listen to music to fall asleep (44.4%), and described bed sharing (33.3%), indicating sleep‐anxiety and sleep‐associations. Symptoms of excessive‐daytime‐sleepiness were frequently reported [un‐refreshed in the morning (38.9%), daytime sleepiness (44.4%), and daytime naps (55.6%)]. Parents frequently observed difficulty of organizing tasks (66.7%), and easy distractibility (88.9%). Sleep problems such as sleep‐disordered breathing, sleep‐related anxiety and sleep associations, disturbed sleep patterns at night, and excessive daytime sleepiness are frequent in children with SLOS. © 2011 Wiley‐Liss, Inc.
Submicroscopic deletion in 7q31 encompassing CADPS2 and TSPAN12 in a child with autism spectrum disorder and PHPV
Authors: Okamoto Nobuhiko , Hatsukawa Yoshikazu , Shimojima Keiko , Yamamoto Toshiyuki
Published: May 2011

We performed array comparative genomic hybridization utilizing a whole genome oligonucleotide microarray in a patient with the autism spectrum disorders (ASDs) and persistent hyperplastic primary vitreous (PHPV). Submicroscopic deletions in 7q31 encompassing CADPS2 (Ca2+‐dependent activator protein for secretion 2) and TSPAN12 (one of the members of the tetraspanin superfamily) were confirmed. The CADPS2 plays important roles in the release of neurotrophin‐3 and brain‐derived neurotrophic factor. Mutations in TSPAN12 are a relatively frequent cause of familial exudative vitreoretinopathy. We speculate that haploinsufficiency of CADPS2 and TSPAN12 contributes to ASDs and PHPV, respectively. © 2011 Wiley‐Liss, Inc.
Adsorption of albumin‐bound toxins on anion exchange resin: an equilibrium study
Authors: Annesini M. C. , Piemonte V. , Turchetti L.
Published: May 2011

Bilirubin and tryptophan are among the albumin‐bound toxins that must be removed from blood during liver‐failure therapy. Artificial liver support devices currently used in clinical practice remove these types of toxins by means of different processes, that are mainly based on adsorption. In this paper, bilirubin and tryptophan adsorption isotherms on anion exchange resin with different albumin concentrations are presented. The results show that the adsorbed amount of toxin decreases with increasing albumin concentration in the solution. This behaviour has been analyzed by means of an original semi‐empirical adsorption model that takes in to account the effect of albumin on toxins adsorption equilibrium. The model highlights that this phenomenon is principally because of the competitive binding of toxin between albumin and sorbent, but, in the case of bilirubin, the reduction in the adsorbed amount of toxin was higher than what can be predicted by considering only this phenomenon. From a different point of view, the experimental results show that the anion exchange resin tested is a suitable sorbent for bilirubin removal, while its adsorption capacity for tryptophan is very low and, therefore, different sorptive media should be considered to remove this compound. Copyright © 2011 Curtin University of Technology and John Wiley & Sons, Ltd.
Explicit extraction of topical context
Authors: Kaptein Rianne , Kamps Jaap
Published: May 2011

This article studies one of the main bottlenecks in providing more effective information access: the poverty on the query end. We explore whether users can classify keyword queries into categories from the DMOZ directory on different levels and whether this topical context can help retrieval performance. We have conducted a user study to let participants classify queries into DMOZ categories, either by freely searching the directory or by selection from a list of suggestions. Results of the study show that DMOZ categories are suitable for topic categorization. Both free search and list selection can be used to elicit topical context. Free search leads to more specific categories than the list selections. Participants in our study show moderate agreement on the categories they select, but broad agreement on the higher levels of chosen categories. The free search categories significantly improve retrieval effectiveness. The more general list selection categories and the top‐level categories do not lead to significant improvements. Combining topical context with blind relevance feedback leads to better results than applying either of them separately. We conclude that DMOZ is a suitable resource for interacting with users on topical categories applicable to their query, and can lead to better search results.
Dealing with Crystal Forms (The Kingdom of Serendip?)
Authors: Braga Dario , d'Agostino Simone , Dichiarante Elena , Maini Lucia , Grepioni Fabrizia
Published: May 2011

The variety of crystal forms that may be associated with one specific molecule of interest can be extremely large: in addition to polymorphs, all sorts of crystalline solids can be obtained, from molecular and ionic co‐crystals to hydrates/solvates, to, needless to say, polymorphs of all these new crystal forms. Lack of predictability of crystallization experiments, far from representing a failure or a nuisance, should encourage in the crystal maker the same attitude shown by the three princes of Serendip (who were making unexpected discoveries by virtue of their “sagacity and readiness of mind”) to be ready to pick new avenues as the crystal experiments will yield something unplanned for.
Thermally Stable Intermolecular Proton Bonds in Polyaromatic Aldehyde Crystals
Authors: Heo Sung Woo , Hwang In‐Chul , Chun Young , Lee Jung Woo , Singh N. Jiten , Kim Seung Bin , Kim Kwang S.
Published: May 2011

We have synthesized self‐assembled red‐colored proton complexes of the aldehyde derivatives of polyaromatic hydrocarbon with strong intermolecular hydrogen bonding. These intermolecularly proton‐bonded polyaromatic aldehydes formed as 1‐pyrenecarbaldehyde (Py‐CHO) reacted with HAuCl4 to produce [(Py‐CHO)2H][AuCl4] under dry conditions. The formation of [(Py‐CHO)2H][AuCl4] was confirmed by single‐crystal structure determination and IR spectral analysis at various temperatures. The compounds are distinctively hydrophobic in nature and are soluble only in a few organic polar solvents. The proton bonds are clearly observed from both the electron density in X‐ray analysis and the characteristic IR frequency signature. The proton complex units have an OH+O distance of the typical Zundel‐like cationic hydrogen bond (in which two O atoms share a proton‐like H in the midpoint of the short OO distance of ≈2.4 Å). The proton bonds are thermally stable, even over 100 °C, because the complexes are stabilized in layered structures with π–π intermolecular interactions of the polyaromatic hydrocarbon ligands. The IR signatures at around 900, 1200, and 1700 cm−1 for the Zundel‐like proton bond are clearly characterized.
Chemical‐dynamical Modelling of the Atmosphere with Emphasis on the Methane Oxidation
Authors: Berntsen Terje , Isaksen Ivar S. A. , Fuglestvedt Jan S.
Published: May 2011

A brief general discussion of coupled chemical dynamical model applied in atmospheric chemistry is given. The basic concepts of lagrangian versus eulerian models and the averaging along one or more directions in space in eulerian models are discussed. A model can be viewed as set of relations and assumptions based on physical laws used to interpret how the input data determine the composition of the atmosphere. An overview of the necessary input data for such models and how their uncertainties influence the output of the models is given. Finally some new results from our 2‐D photochemical tracer/transport model for the troposphere are used as an example of how such models can be used. The methane oxidation system is studied, and a significant feedback (35% at present) between increased emissions and concentrations of methane is found. Several aspects of the altered chemical composition is discussed to explain the calculated feedback including a primary (total HOx‐budget) and a secondary (NOx‐induced) mechanism and changes in the OH/HO2 ratio within the HOx‐reservoir.
Atmospheric CO2: Global Change and Regulation Mechanisms
Authors: Oeschger H.
Published: May 2011

For the estimate of the distribution in the carbon system of the CO2 emitted into the atmosphere due to human activities, the exchange of carbon between atmosphere and ocean, and between atmosphere and biosphere needs to be considered. Information on this spreading of excess CO2 can be obtained from measurements of a.o. CO2, 13C/12C, 14C/C in the atmosphere, of natural and nuclear weapon produced 14C in the ocean and in the biota and of other natural or anthropogenic tracers. — Based essentially on such information, models for the CO2 uptake by the carbon system have been developed which are capable of reproducing the result of the drop in the rate of increase of CO2 emissions from 4.5% to 2% per year following the oil‐embargo in 1973. — Of special interest regarding the understanding of the carbon cycle and its role in controlling the climate of the Earth are the observations in polar ice cores covering the past 160.000 years, corresponding to one and a half glaciation cycles. They show variations of atmospheric CO2, CH4 and N2O parallel to the climatic variations. Measurements of 13C/12C in shells of foraminiferas support the hypothesis that these CO2 changes are caused by changes in the ocean's biological pump, i.e. the flux of detrital organic carbon from the surface to the deep ocean, which affects the total inorganic carbon in the surface ocean and the partial pressure of CO2.
Effects of Solid‐Fueled Rocket Exhausts on the Stratospheric Ozone Layer
Authors: Krüger B. C. , Hirschberg M. M. , Fabian P.
Published: May 2011

Space transport systems often use solid‐fuel in boosters and this type of fuel is also very common for sounding rockets. One of the main components in the exhaust is hydrochloric acid. Photochemical model calculations have been performed to investigate local effects after such a rocket launch. Disturbances of the atmospheric trace gas distribution are possible; however, strong changes in the stratospheric ozone concentration are restricted to altitudes above 30 km and will only occur if the mixing of the exhaust gas with ambient air proceeds slowly.
Stratospheric Ozone Variability over Spitsbergen in March – April 1991
Authors: Rummukainen Markku , Joffre Sylvain , Damski Juhani , Gathen Peter Von Der
Published: May 2011

The Finnish Meteorological Institute, the Alfred Wegener Institute and Bremen University jointly performed upper atmospheric soundings from Ny Ålesund, Spitsbergen (79°N, 12°E) between March 11 and April 24, 1991. The soundings were made using Vaisala radiosondes and ECC ozone sondes and produced a good picture of ozone behaviour in the lower and middle stratosphere. With one exception, the soundings were carried out daily or at least every other day with most of them reaching altitudes higher than 30 km. – The temperature record reveals that in the middle of the experiment stratospheric warming took place. The warming was also reflected in the rising trend of total ozone. In addition to this transition from winter to spring conditions in the polar stratosphere, there was also considerable variability in both the total ozone content and the vertical variability of ozone concentrations. The reasons for these seem to be to a large extent dynamical in origin.
Tropospheric OH: Local Measurements and Their Interpretations
Authors: Comes F. J. , Armerding W. , Grigonis R. , Herbert A. , Spiekermann M. , Walter J.
Published: May 2011

Recently two campaigns have been conducted on the “Schauinsland” (Black Forest, Germany). The concentration of tropospheric OH and its diurnal variation was measured for a number of consecutive days. Together with it the concentrations of O3, H2O, NOx, and the intensity of the UV were monitored to obtain the necessary background information. The experimental technique for the OH detection is based on OH resonance absorption in the UV in a multireflection cell of 6 m length. The linear dimensions of the cell determine the local character of the measurements.
Simultaneous Long Path Field Measurements of HNO2, CH2O and Aerosol
Authors: Notholt J. , Hjorth J. , Raes F. , Schrems O.
Published: May 2011

Field measurements have been performed to study the influence of heterogeneous processes on the trace gas concentration of HNO2 and CH2O in the atmosphere. The observations indicate that during foggy episodes HNO2 is formed to a high extent when NO, NO2 and aerosols are present simultaneously. Far more CH2O is found to be dissolved in the aerosol droplets than what is expected from the literature value of the Henry constant.
Remote Sensing of Atmospheric Trace Constituents Using Fourier Transform Spectrometry
Authors: Fischer H.
Published: May 2011

The investigation of changes in ozone concentration and of the increase of the greenhouse effect requires simultaneous and global observations of atmospheric trace species. Obviously, IR‐Fourier Transform Spectrometers (FTIR) are especially appropriate for this measurement task due to their capability to detect wide spectral intervals with high spectral resolution. FTIR experiments for measuring trace species have already been performed during the last ten years. Some of the very interesting results as derived from these measurements are presented, for example the wide range of mixing ratio profiles and the variety of trace gases detected by the ATMOS (Atmospheric Trace Molecule Spectroscopy) experiment. These contributions to atmospheric research were already essential even if no cooled interferometer for time‐independent emission measurements has been flown aboard aircrafts or in space so far. – The objective to fly a cooled FTIR in space leads to a novel optical design, the socalled double pendulum interferometer (DPI). The DPI is the core part of several MIPAS (Michelson Interferometer for Passive Atmospheric Sounding) experiments which have already been used for atmospheric measurements. Infrared solar absorption spectra of the atmosphere were taken during the CHEOPS III campaign in Sweden in winter 1990 in order to obtain time series of zenith column amounts of several trace gases. The first two field experiments of the cooled MIPAS have been performed during stratospheric balloon flights in France in May 1989 and 1990. Limb emission spectra were measured within the altitude range between 7 and 38 km. A number of atmospheric trace species are identified, namely CO2, O3, H2O, CH4, N2O, CCl4, CF2Cl2, CFCl3, CHF2Cl, ClONO2, HNO3, N2O5 and C2H6. Besides the MIPAS ground based and the MIPAS balloon experiment our new cooled MIPAS aircraft experiment will be operated during the EASOE (European Arctic Stratospheric Ozone Exp.) campaign as scheduled for winter 1991/92. The cooled MIPAS space experiment is in development for the 1. European Polar Platform and the German Environmental Research Satellite ATMOS.
The Numerical Modelling of the Sedimentation of Polar Stratospheric Cloud Particles
Authors: Müller Rolf , Peter Thomas
Published: May 2011

The denitrification of the polar night stratosphere is crucially controlling the amount of stratospheric ozone depletion over both the Arctic and Antarctic. It is accomplished through the formation and sedimentation of polar stratospheric cloud (PSC) particles. The latter process, though conceptionally simple, is not easily incorporated into numerical PSC models. We present results of computational experiments demonstrating advantages and pitfalls of various numerical methods. The velocity profiles which are assumed are similar to real particle velocity profiles, but simple enough to allow an analytic solution of the advection equation. The proposed schemes are upwind biased finite volume schemes, possessing many desired properties, in particular mass conservation and positive definiteness. Numerical diffusion presents a major problem, particularly since PSCs are observed to exhibit pronounced layering which requires the modelling of steep gradients in the particle number density. On the other hand, artificial structures can be introduced if semi‐Lagrangian advection over several grid boxes is allowed. Procedures obviating these difficulties are described, in particular polynomial fitting, and the computational efficiency of the schemes is investigated. We conclude that polynomial fitting is a suitable method for treating PSC Type‐I particles, whereas we recommend a novel semi‐Lagrangian method, designed so that artificial structures can be avoided, for PSC Type‐II particles.
Formation and the Physico‐chemical Properties of the Tropospheric Aerosol
Authors: Winkler Peter , Kaminski Uwe
Published: May 2011

An evaluation of the long‐term records of aerosol and meteorological parameters at the Meteorological Observatory of Hamburg reveals that particle production in the nucleation mode is stimulated by solar radiation and is enhanced by elevated SO2 or NOx concentrations. While the particle number increases, their average sulfate or nitrate content per particle decreases with increasing sunshine. In the accumulation and coarse mode sulfate production takes place even at relative humidities above 80% but no nitrate production, while in the nucleation mode, nitrate production occurs at high humidities but only a weak sulfate production. The nitrate to sulfate ratio shows a winter maximum and a summer minimum in the course of the year and a long term increase over the past 6 years in both size ranges. The sulfate content of the Aitken particles shows a broad maximum in autumn. Coagulation causes a rapid mass transfer from the nucleation to the accumulation mode at high concentrations (>100 cm−3) of large particles. In the long‐term trend, the aerosol mass showed an increase between 1976 and 1986 and a decrease since then but the number concentration of the large particles (0.1 ≤ r ≤ 1 μm) is still increasing. This aerosol fraction has the longest atmospheric residence time. The Aitken particle number has reduced since 1980 most probably caused by a reduction of the SO2 concentration. With respect to physico‐chemical properties, the particle growth with relative humidity and the problem of internal or external mixing are discussed.
Global Changes of Aerosols – Ground Based Monitoring of the Optical Thickness in Polar Regions and Central Europe
Authors: Leiterer Ulrich , Weller Michael , Herber Andreas
Published: May 2011

Optical thickness measurements in north polar, south polar and Central European regions are presented and discussed in comparison with earlier values. Actinometer measurements of the integral optical thickness in the Arctic (Franz‐Joseph‐Land) from 1933 to 1942 show an average level of about 0.22 and only minor changes between spring and summer and from year to year. Since 1955 the spring values show a pronounced increase to 0.3 in 1985. In contrast to this behaviour, the levels in Antarctica (Mirny) are much lower (around 0.18) and fairly stable between 1957 and 1990 except for two time periods with strong volcanic activities with peaks up to 0.28. – Spectral aerosol thickness data at 500 and 1000 nm for Antarctica (G. Forster) from 1955 to 1990 indicate volcanic activity markedly with data rising from a level around 0.03 to two maxima of about 0.12. In March 1989, the boundary layer extinction coefficient at 500 nm in the Arctic reached the 79‐fold of the Antarctic and the 2.5‐fold of the Central Europe values at Lindenberg. The very high winter and spring aerosol extinction coefficients in the Arctic result from long‐range transport and gas‐to‐particle conversion of NOx and SO2.
Photochemistry of Atmospheric Trace Gases
Authors: Schurath U.
Published: May 2011

The complex scheme of atmospheric radical chain reactions is driven by a relatively small number of photodissociation processes. The most important ones in the troposphere are the formation of O(1D) by the photolysis of ozone (frequency J1), and the photolysis of NO2 (frequency J2). It is shown that uncertainties in J1 and J2 lead to large uncertainties in model‐predicted species concentrations, particularly in OH levels. Methods of calculating/measuring J1 and J2 will be discussed.
N2O Formation in the Reactive Collisional Quenching of NO3* and NO2* by N2
Authors: Zellner R. , Hartmann D. , Rosner I.
Published: May 2011

The formation of N2O in the reactive collisional quenching of NO3 (Ã2E') and NO2 (Ã2B1, 2B2) by N2 at 298 K has been determined using a dye laser excitation technique combined with product accumulation/g.c. analysis. The absolute yield of N2O is found to be proportional to the number of photons absorbed (Npe) into non‐dissociative states of the electronically excited species. The relative N2O yields (ΔN2O/Npe) have been determined as ϕ1 = (1.4 ± 0.6) · 10−2 and ϕ2 = (4.0 ± 2.0) · 10−4 for the quenching of NO3* and NO2*, respectively. As a consequence of high pumping rates of NO3* and NO2* in the daytime atmosphere these processes represent a significant in situ chemical source of atmospheric N2O.
Spectroscopy and Photochemistry of Chlorine Dioxide
Authors: Vaida V. , Richard E. C. , Jefferson A. , Cooper L. A. , Flesch R. , Rühl E.
Published: May 2011

The photoreactivity of chlorine dioxide excited in the near ultraviolet is reexamined in this paper. The results of this study are used to evaluate the possible role that the photochemistry of OClO may play in polar ozone depletion. – The study reported here involves high resolution spectroscopic and photofragment experiments of isolated gas phase OClO and of OClO clustered with water. The results show that excitation in the near ultraviolet of the A(2A2) ← X(2B1) transition leads to both dissociation to form vibrationally excited ClO and O, and to rearrangement which ultimately leads to Cl and O2. Formation of Cl and O2 may contribute to catalytic polar ozone depletion. The mechanism and quantum yield for these two photoreactions are discussed. The quantum yields for the two excited state reactions are very sensitive to perturbations by intermolecular interactions. The heterogeneous photoreactivity of OClO is probed in (H2O)n clusters.
Product Quantum Yields for the 350 nm Photodecomposition of Pyruvic Acid in Air
Authors: Berges Markus G. M. , Warneck Peter
Published: May 2011

Quantum yields for the products CH3CHO, CO2 and CH3COOH in the 350 nm photodecomposition of pyruvic acid are 0.48 ± 0.01, 1.27 ± 0.18 and 0.14, respectively, as measured in air at atmospheric pressure. In the presence of NO2 the quantum yield for CH3CHO was reduced to 0.30 ± 0.04 and peroxyacetyl nitrate was formed with a quantum yield of 0.15 ± 0.02. This is taken to indicate the formation of acetyl radicals in one of the primary processes.
A Fast Algorithm to Calculate the Photonflux in Optically Dense Media for Use in Photochemical Models
Authors: Röth Ernst‐Peter
Published: May 2011

A photon flux model is described which determines the photodissociation coefficients for the simulation of atmospheric chemistry with a very fast algorithm. Emphasis is laid on the calculation of the radiative transfer in optically thick media, e.g. in clouds. The concept of Kubelka and Munk [1] has been adapted to atmospheric conditions. The algorithm is described in detail, and general aspects of the radiative transfer in clouds are presented. To prove the accuracy of the algorithm, the results are compared to those gained by a more sophisticated model.
Reactions of Ozone with Unsaturated Organic Compounds
Authors: Treacy Jack , Hag Mohamed El , O'Farrell Denis , Sidebottom Howard
Published: May 2011

Rate constants for the gas‐phase reactions of ozone with a series of alkenes have been determined using a conventional static system. Ozone loss was monitored in excess of the hydrocarbon and rate data measured at 1 atmosphere total pressure over the temperature range 240–324 K. The Arrhenius parameters obtained are discussed in terms of structure‐reactivity relationships. Product studies have been carried out for the reaction of O3 with the conjugated dienes, 1,3‐butadiene, 2‐methyl‐1,3‐butadiene (isoprene) and 2,3‐dimethyl‐1,3‐butadiene in air. The results provide information on the decomposition pathways for the primary ozonides and the relative importance of ozone addition to the two double‐bonds in isoprene.
Gas Phase Studies on Chloryl Chloride, ClClO2
Authors: Müller Holger S. P. , Willner Helge
Published: May 2011

ClClO2 has been generated by reacting FClO2 with BCl3 or HCl in the gas phase at room temperature. It is also formed in the reaction of photolytically generated Cl‐atoms with ClO2. One weak and three strong fundamentals as well as two weak combination bands were observed in the mid infrared region. In the UV‐region ClClO2 strongly absorbs, exhibiting maxima at 231 and 296 nm with σ = 1.3 and 1.5 · 10−17 cm2 molecule−1. Decomposition of ClClO2 follows second order with a halflife of 60s at 1.0 mbar partial and 4 mbar total pressure, resulting in ClO2 and Cl2.
Effect of Temperature on the Dissociative and Nondissociative Electron Attachment to Freons
Authors: Christophorou L. G. , Datskos P. G. , Carter J. G.
Published: May 2011

The attachment of slow electrons to freons (including many atmospheric halocarbons) depends rather strongly on the gas temperature. In general, as the temperature increases, dissociative electron attachment increases and nondissociative electron attachment decreases; the former behavior is principally due to increase in autodissociation and the latter principally due to increase in autodetachment of the transient anion.
The Arrhenius Equation: Limits of Validity under Extreme Reaction Conditions
Authors: Stiller W.
Published: May 2011

Photon‐induced molecular dissociation increases the portion of radical reactions which in general can be treated in the framework of chemical equilibrium kinetics of the translational degrees of freedom of the reagents. In particular an “inversion” of the Arrhenius equation gives a reactive “Arrhenius” cross section which shows a wide (but limited) spectrum of possibilities describing bimolecular gas phase reactions in the framework of Arrhenius kinetics. The occurrence of charged particles and energy‐rich cosmic, solar and magnetospheric species and the presence of electromagnetic fields lead to nonequilibrium situations which have to be described by the chemical nonequilibrium kinetics deviating from Arrhenius kinetics.
Aqueous‐Phase Chemical Processes in Deliquescent Seasalt Aerosols
Authors: Chameides W. L. , Stelson A. W.
Published: May 2011

The aqueous‐phase chemistry of deliquescent seasalt aerosols in the remote marine boundary layer is investigated with a steady‐state box model. The model simulates the scavenging of soluble and reactive gaseous species by the seasalt aerosols, the chemical reactions of these species and seasalt ions in the deliquescent solution, and changes in the aerosol composition that occur as a result of these processes. Because of the alkalinity of seasalt, the calculations indicate that deliquescent seasalt aerosols are strongly buffered and as a result their pH remains close to 8 until the amount of acid added to the aerosol solution exceeds the alkalinity. The oxidation of chloride by O3 as well as by free radicals are found to proceed at extremely slow rates and thus these reactions can not explain the high chloride deficits recently observed over the North Atlantic Ocean. On the other hand, the oxidation of dissolved SIV by O3 in seasalt aerosols is found to proceed at an extremely high rate and appears to explain the observations of nss‐SO42‐ in seasalt aerosols over the Noth Atlantic Ocean. The high rate of SIV oxidation is found to proceed until the amount of nss‐SO42‐ generated in the aerosol is sufficiently large to overwhelm the buffering capacity and lower the pH below 5.5. As a result, the calculations suggest a strong coupling between the cycles of S and alkalinity in the marine boundary layer that may act to limit the generation of cloud condensation nuclei from the oxidation of biogenic S emissions.
Laser‐Based Studies of Reactions of the Nitrate Radical in Aqueous Solution
Authors: Exner M. , Herrmann H. , Zellner R.
Published: May 2011

A new experimental technique for temperature dependent studies of the kinetics of the nitrate radical (NO3) in aqueous solution has been developed. In this technique NO3 is produced by excimer laser photolysis of peroxodisulfate anions at 351 nm in the presence of excess nitrate and detected by time‐resolved long‐path laser absorption using the 632.8 nm line of a HeNe‐laser. — For the generation reaction of NO3, viz. (1) SO4− + NO3− SO42‐ + NO3 a rate constant of k1 = (5.0 ± 0.5) · 104 l mol · s at T = 298 K and zero ionic strength was found. For the reactions (2) NO3 + OH− NO3− OH and (3) NO3 + Cl− NO3− + Cl rate coefficients of k2 = (8.2 ± 0.9) · 107 and k3. = (1.0 ± 0.2) · 107 l/mol · s were determined at T = 298 K. In temperature dependent experiments the Arrhenius expressions k2(T) = (8.1 ± 0.4) · 1011 exp[‐(2700 ± 400)K/T] l/mol · s and k3(T) = (1.9 ± 0.2) · 1013 exp[‐(4300 ± 500) K/T] l/mol · s were derived. ‐ The rate constant of the reaction of NO3 with dissolved sulfur (IV) has been studied over a range of pH‐values and temperature. For the reactions with SO2(aq) (4). and HSO3− (5) rate coefficients of k4 = (2.3 ± 0.5) · 108 and k5 = (1.4 ± 0.1) · 109 l/mol · s, respectively, at 298 K were obtained. The corresponding temperature dependences are described by: k4(T) = (5.6 ± 0.7) · 1013 exp[‐(3700 ± 1100)K/T] l/mol · s and k5(T) = (1.1 ± 0.2) · 1012 exp[‐(2000 ± 400)K/T] l mol · s. For the reaction of NO3 with SO32‐ (6) a rate constant of k6 = (3.0 ± 0.4) · 108 l/mol · s was derived at T = 278 K.
Ozone Destruction on Powders
Authors: Alebić‐Juretić A. , Cvitaš T. , Klasinc L.
Published: May 2011

The destruction of ozone on silica‐gel, alumina, sodium chloride, calcite, Saharan sand and wood ash as model powders was studied in a fluidized bed reactor. An elevated ambient concentration of ozone (100 ppb) in the filtered air stream was applied during the experiments. The relative effectiveness of ozone destruction was in the order alumina > wood ash > silica‐gel, followed by Saharan sand > calcite > sodium chloride. The implication of this result on ozone measurements in particle‐rich atmospheres is discussed.
On the Variability of the Stratosphere in the Arctic Regions in Winter
Authors: Labitzke K.
Published: May 2011

The arctic stratosphere is much more variable in winter, and from one winter to another, than is the antarctic stratosphere. The latter stays cold and intense through the winter, whereas the former is subject to minor and major midwinter warmings. During the major midwinter warmings the arctic warms up and the cyclonic vortex — normally centered near the North Pole — divides into two centers which move south while an anticyclone becomes established near the pole. — Because the antarctic polar cyclonic vortex remains cold and centered near the pole till the end of winter, conditions favorable for the development of an ozone hole exist when the sun returns in spring. This is in contrast to the disturbed conditions in the arctic which usually keep the temperature at a level that is not conducive to large‐scale destruction of ozone.
Luminescence properties of a nanoporous freshwater diatom
Authors: Goswami Bondita , Choudhury Amarjyoti , Buragohain Alak K.
Published: May 2011

Freshwater diatom frustules show special optical properties. In this paper we observed luminescence properties of the freshwater diatom Cyclotella meneghiniana. To confirm the morphological properties we present scanning electron microscopy (SEM) images. X‐ray diffraction (XRD) studies were carried out to visualize the structural properties of the frustules, confirming that silica present in diatom frustules crystallizes in an α‐quartz structure. Study of the optical properties of the silica frustules of diatoms using ultra‐violet‐visible (UV‐vis) spectroscopy and photoluminescence spectroscopy confirmed that the diatom C. meneghiniana shows luminescence in the blue region of the electromagnetic spectrum when irradiated with UV light. This property of diatoms can be exploited to obtain many applications in day‐to‐day life. Also, using time‐resolved photoluminescence spectroscopy (TRPL) it was confirmed that this species of diatom shows bi‐exponential decay. Copyright © 2011 John Wiley & Sons, Ltd.
Recurrent groin hernia surgery
Authors: Sevonius D , Gunnarsson U , Nordin P , Nilsson E , Sandblom G
Published: May 2011

Background

The reoperation rate after recurrent groin hernia surgery is more than twice that recorded for primary groin hernia procedures. The aim was to define the outcome from routine redo hernia surgery by analysing a large population-based cohort from a national hernia register.

Methods

All recurrent groin hernia operations registered in the Swedish Hernia Register from 1992 to 2008 were analysed using multivariable analysis with stratification for preceding repair.

Results

Altogether 174 527 hernia operations were recorded in the Swedish Hernia Register between 1992 and 2008, including 19 582 reoperations. The preceding repair was included in the register for 5565 of these recurrent repairs. With laparoscopic repair as reference standard, the hazard ratio for recurrence was 2·55 (95 per cent confidence interval 1·66 to 3·93) after sutured repair, 1·53 (1·20 to 1·95) after Lichtenstein repair, 2·31 (1·76 to 3·03) after plug repair, 1·36 (0·95 to 1·94) after open preperitoneal mesh and 3·08 (2·22 to 4·29) after other repairs. Laparoscopic and open preperitoneal repair were associated with a lower risk of reoperation following a preceding open repair (P < 0·001), but no technique differed significantly from the others following a preceding preperitoneal repair.

Conclusion

The laparoscopic and the open preperitoneal mesh methods of repair for recurrent groin hernias were associated with the lowest risk of reoperation. Although the method of repair in previous surgery must be considered, these techniques are the preferred methods for recurrent groin hernia surgery.
Systematic review of outcome of downstaging hepatocellular cancer before liver transplantation in patients outside the Milan criteria
Authors: Gordon-Weeks A N , Snaith A , Petrinic T , Friend P J , Burls A , Silva M A
Published: May 2011

Background

The aim of this systematic review was to assess the evidence on tumour downstaging before liver transplantation in patients with hepatocellular carcinoma (HCC) initially staged beyond the Milan criteria.

Methods

MEDLINE (from 1952), Embase (from 1980) and the Cochrane Library were searched. The review included cohort studies that reported the outcomes of patients with HCC outside the Milan criteria who underwent downstaging before transplantation.

Results

Eight studies met the inclusion criteria and included a total of 720 patients who underwent transplantation following downstaging after initial presentation with disease outside the Milan criteria. The rate of successful downstaging varied from 24 to 69 per cent of patients. Reported survival rates ranged from 82 to 100 per cent, 79 to 100 per cent and 54·6 to 94 per cent at 1, 3 and 5 years respectively. These were comparable with results for patients presenting within the Milan criteria.

Conclusion

Successful downstaging of HCC to within the Milan criteria is feasible in a proportion of patients. Absolute and disease-free survival rates in patients transplanted following downstaging are comparable to those in patients within the Milan criteria.
Development and validation of a highly sensitive LC‐MS/MS method for quantitation of dexlansoprazole in human plasma: application to a human pharmacokinetic study
Authors: Hotha Kishore Kumar , Vijaya Bharathi D. , Jagadeesh B. , Ravindranath L. K. , Jaya Veera K. N. , Venkateswarulu V.
Published: May 2011

A highly sensitive, specific and simple LC‐MS/MS method was developed for the simultaneous estimation of dexlansoprazole (DEX) with 50 μL of human plasma using omeprazole as an internal standard (IS). The API‐4000 LC‐MS/MS was operated under multiple reaction‐monitoring mode using electrospray ionization. A simple liquid–liquid extraction process was used to extract DEX and IS from human plasma. The total run time was 2.00 min and the elution of DEX and IS occurred at 1.20 min. This was achieved with a mobile phase consisting of 0.2% ammonia–acetonitrile (20:80, v/v) at a flow rate of 0.50 mL/min on an X‐terra RP 18 (50 × 4.6 mm, 5 µm) column. The developed method was validated in human plasma with a lower limit of quantitation of 2 ng/mL for DEX. A linear response function was established for the range of concentrations 2.00–2500.0 ng/mL (r > 0.998) for DEX. The intra‐ and inter‐day precision values for DEX met the acceptance criteria as per FDA guidelines. DEX was stable in the battery of stability studies, viz. bench‐top, auto‐sampler and freeze–thaw cycles. The developed assay method was applied to an oral bioequivalence study in humans. Copyright © 2011 John Wiley & Sons, Ltd.
In vivo metabolism study of polygalic acid in rat using HPLC‐ESI‐MSn
Authors: Ling Yun , Wu Bin , Wang Ke , Liu Huihui , Chen Luying , Fan Mingsong , Sun Zhaolin , Huang Chenggang
Published: May 2011

A very simple and direct method has been established for the determination of polygalic acid and its metabolites in rat urine based on HPLC coupled with electrospray ionization multi‐stage tandem mass spectrometry (HPLC‐ESI‐MSn). The rats were administered a single dose (100 mg/kg) of polygalic acid by oral gavage. The urine samples were collected and purified through a C18 solid‐phase extraction cartridge, and then these pretreated samples were injected into a reversed‐phase C18 column with a gradient elution program, whereas acetonitrile–0.5% aqueous formic acid was used as mobile phase and detected by an on‐line MS/MS system. As a result, the parent drug and its four metabolites were identified and characterized in rat urine for the first time by comparing their changes in molecular mass (ΔM), retention times and full‐scan MSn spectra with those of the parent drug. A possible metabolic pathway of polygalic acid was investigated and proposed. More importantly, the results demonstrated that the newly developed method (HPLC‐ESI‐MSn) was sensitive, simple and suitable for the determination of polygalic acid and its metabolites in biological samples. Copyright © 2011 John Wiley & Sons, Ltd.
The impact of unsuccessful percutaneous coronary intervention on short‐ and long‐term prognosis in STEMI and NSTEMI
Authors: Mazurek Michal , Kowalczyk Jacek , Lenarczyk Radoslaw , Swiatkowski Andrzej , Kowalski Oskar , Sedkowska Agnieszka , Was Tomasz , Swierad Marcin , Pruszkowska‐Skrzep Patrycja , Kurek Tomasz , Jedrzejczyk Ewa , Polonski Lech , Kalarus Zbigniew
Published: May 2011

Objectives: To compare the impact of the efficacy of percutaneous coronary intervention (PCI) on prognosis in ST and non‐ST elevation myocardial infarction (STEMI and NSTEMI) patients with respect to infarct‐related artery (IRA). Background: The significance of the efficacy of PCI in STEMI and NSTEMI depending on the type of IRA has yet to be clarified. Methods: Study population consisted of 2,179 STEMI and 554 NSTEMI consecutive patients treated with urgent PCI. The efficacy of PCI (TIMI [thrombolysis in myocardial infarction] 3 vs. TIMI < 3) was assessed with regard to the type of IRA (left anterior descending artery, circumflex artery [Cx] or right coronary artery). The mean follow‐up was 37.5 months. Results: The rate of unsuccessful PCI was similar in STEMI and NSTEMI irrespectively of IRA (14.1 vs. 17.7%; P = 0.062). In STEMI, unsuccessful PCI was associated with significantly higher early (23.1 vs. 5.6%; P < 0.001) and late (29.9 vs. 12.8%; P < 0.001) mortality regardless of IRA. In NSTEMI, the inefficacious PCI significantly increased early (19.0% vs. 0.9%; P < 0.001) and late (27.3% vs. 6.3%; P < 0.001) mortality only in patients with Cx‐related infarction. Unsuccessful PCI of IRA was an independent risk factor for death in STEMI (HR 1.64; P < 0.05), but not in NSTEMI (P = 0.64). Further analysis showed that whilst unsuccessful PCI of any vessel in STEMI is an independent risk factor for death, in NSTEMI this applies to unsuccessful PCI of Cx only. Conclusions: The significance of unsuccessful PCI of IRA seems to be different in STEMI and NSTEMI. Unsuccessful PCI is an independent risk factor for death in STEMI regardless of IRA and in NSTEMI with the involvement of Cx. © 2010 Wiley‐Liss, Inc.
Flame Aerosol Synthesis of Metal Oxide Catalysts with Unprecedented Structural and Catalytic Properties
Authors: Schimmoeller Bjoern , Pratsinis Sotiris E. , Baiker Alfons
Published: May 2011

In the past two decades flame aerosol synthesis of novel materials has experienced significant growth in both industry and academia. Recent research is focused on the development of new materials in the nanosized range to be used in various applications, such as catalysts, gas sensors, pigments, and batteries. Several studies indicate that this scalable synthesis method can result in novel and metastable phases of mixed metal oxides of high purity, which may not be easy accessible by conventional wet‐ or solid‐state processes. Especially for catalytic applications this synthesis method is emerging as an attractive fast and single‐step production route for high surface area materials, often with unprecedented structural and catalytic properties. The large variety of possible organometallic precursors especially for the liquid‐fed aerosol flame synthesis makes this technique very versatile for catalyst synthesis.

Using the example of the widely used vanadia‐based mixed oxide catalysts, we analyze the structural and catalytic properties of flame‐derived catalysts and compare them to corresponding catalysts prepared by classical wet‐chemistry methods. The often unique structural properties along with their control at proper synthesis conditions and their influence on catalyst performance in selected reactions are discussed. Subsequently, we give an overview of other recent flame‐made mixed metal oxide based catalysts and make an attempt to assess the potential and limitations of flame synthesis for the preparation of catalytic mixed metal oxide materials, and finally we identify future challenges in research.
Mechanism of the Catalytic Oxidation of Glycerol on Polycrystalline Gold and Platinum Electrodes
Authors: Kwon Youngkook , Schouten Klaas Jan P. , Koper Marc T. M.
Published: May 2011

This paper addresses the oxidation mechanism of glycerol on Au and Pt electrodes under different pH conditions. Intermediates and/or reaction products were detected by using an online high‐performance liquid chromatography technique (for soluble products) and online electrochemical mass spectrometry (for CO2). In alkaline media, the main product of glycerol oxidation on the Pt electrode is glyceric acid produced via glyceraldehyde. Glyceric acid is the primary oxidation product on the Au electrode, which is further oxidized to glycolic acid and formic acid at high potentials (≥0.8 V), yielding high current densities. As the pH of the solution is lowered, the glycerol oxidation becomes significantly more sluggish on both Au and Pt electrodes, which results in glyceraldehyde being the main oxidation product under neutral conditions, especially on gold. In acidic solutions, only the Pt electrode shows catalytic activity with a relatively low conversion rate, mainly to glyceraldehyde. At positive potentials corresponding to the formation of a Pt surface oxide, the PtOx surface oxide catalyzes the conversion of glyceraldehyde finally to formic acid and CO2, but only under acidic conditions. Gold catalyzes glycerol oxidation only under alkaline conditions, in contrast to a “real catalyst,” that is, platinum, which catalyzes glycerol oxidation over the entire pH range.
Discovery, Structure–Activity Relationship Studies, and Crystal Structure of Nonpeptide Inhibitors Bound to the Shank3 PDZ Domain
Authors: Saupe Jörn , Roske Yvette , Schillinger Christian , Kamdem Nestor , Radetzki Silke , Diehl Anne , Oschkinat Hartmut , Krause Gerd , Heinemann Udo , Rademann Jörg
Published: May 2011

Shank is the central scaffolding protein of the postsynaptic density (PSD) protein complex found in cells of the central nervous system. Cellular studies indicate a prominent role of the protein in the organization of the PSD, in the development of neuronal morphology, in neuronal signaling, and in synaptic plasticity, thus linking Shank functions to the molecular basis of learning and memory. Mutations in the Shank gene have been found in several neuronal disorders including mental retardation, typical autism, and Asperger syndrome. Shank is linked to the PSD complex via its PDZ domain that binds to the C‐terminus of guanylate‐kinase‐associated protein (GKAP). Here, small‐molecule inhibitors of Shank3 PDZ domain are developed. A fluorescence polarization assay based on an identified high‐affinity peptide is established, and tetrahydroquinoline carboxylates are identified as inhibitors of this protein–protein interaction. Chemical synthesis via a hetero‐Diels–Alder strategy is employed for hit optimization, and structure–activity relationship studies are performed. Best hits possess Ki values in the 10 μM range, and binding to the PDZ domain is confirmed by 1H,15N HSQC NMR experiments. One of the hits crystallizes with the Shank3 PDZ domain. The structure, analyzed at a resolution of 1.85 Å, reveals details of the binding mode. Finally, binding to PDZ domains of PSD‐95, syntrophin, and DVL3 was studied using 1H,15N HSQC NMR spectroscopy.
Fezf1 and Fezf2 are required for olfactory development and sensory neuron identity
Authors: Eckler Matthew J. , McKenna William L. , Taghvaei Sahar , McConnell Susan K. , Chen Bin
Published: May 2011

The murine olfactory system consists of main and accessory systems that perform distinct and overlapping functions. The main olfactory epithelium (MOE) is primarily involved in the detection of volatile odorants, while neurons in the vomeronasal organ (VNO), part of the accessory olfactory system, are important for pheromone detection. During development, the MOE and VNO both originate from the olfactory pit; however, the mechanisms regulating development of these anatomically distinct organs from a common olfactory primordium are unknown. Here we report that two closely related zinc‐finger transcription factors, FEZF1 and FEZF2, regulate the identity of MOE sensory neurons and are essential for the survival of VNO neurons respectively. Fezf1 is predominantly expressed in the MOE while Fezf2 expression is restricted to the VNO. In Fezf1‐deficient mice, olfactory neurons fail to mature and also express markers of functional VNO neurons. In Fezf2‐deficient mice, VNO neurons degenerate prior to birth. These results identify Fezf1 and Fezf2 as important regulators of olfactory system development and sensory neuron identity. J. Comp. Neurol. 519:1829–1846, 2011. © 2011 Wiley‐Liss, Inc.