bluuebunny/crossref_metadata_2025_split huggingface dataset:
Characteristics and outcome of critically ill patients with 2009 H1N1 influenza infection in Syria
Authors: Alsadat Reem , Dakak Abdulrahman , Mazlooms Mouna , Ghadhban Ghasan , Fattoom Shadi , Betelmal Ibrahim , Abouchala Nabil , Kherallah Mazen 
Published: July 2012

Abstract
Objectives: To describe the epidemiologic characteristics, clinical features, and outcome of severe cases of 2009 H1N1 influenza A infections who were admitted to the intensive care units (ICUs) in Damascus, Syria. Materials and Methods: Retrospectively, we collected clinical data on all patients who were admitted to the ICU with confirmed or suspected diagnosis of severe 2009 H1N1 influenza A with respiratory failure at 4 major tertiary care hospitals in Damascus, Syria. Acute Physiology and Chronic Health Evaluation (APACHE) II system was used to assess the severity of illness within the first 24 h after admission. The outcome was overall hospital mortality. Results: Eighty patients were admitted to the ICU with severe 2009 H1N1 infection. The mean age was 40.7 years; 69.8% of patients had ≥1 of the risk factors: asthmatics 20%, obesity 23.8%, and pregnancy 5%; and 72.5% had acute lung injury or adult respiratory distress syndrome, 12.5% had viral pneumonia, 42.5% had secondary bacterial pneumonia, and 15% had exacerbation of airflow disease. Mechanical ventilation was required in 73.7% of cases. The mean hospital length of stay was 11.7 days (median 8 days, range 0-77 days, IQR: 5-14 days). The overall mortality rate was 51% for a mean APACHE II score of 15.2 with a predicted mortality of 21% (standardized mortality ratio of 2.4, 95% confidence interval: 1.7-3.2, P value < 0.001). Conclusion: Critically ill patients with severe 2009 H1N1 infection in this limited resource country had a much higher mortality rate than the predicted APACHE II mortality rate or when compared with the reported mortality rates for severe cases in other countries during 2009 H1N1 pandemic.
Densitometric Characterization of Aqueous Lipid Dispersions
Authors: Schmidt Günther , Knoll Wolfgang 
Published: July 2012

AbstractAqueous dispersions of multilamellar liposomes of pure lipids and binary lipid mixtures have been investigated by densitometry. It is shown that the employed mechanical oscillator technique is well suited to derive volumetric data of different lipid phases and to characterize the transitions between them. Transition temperatures, widths, volume changes and in some cases also the kinetics can be studied. — For binary lipid alloys temperature‐composition‐phase diagrams can be established. By analysing the thermal expansion a direct comparison with calorimetric data is possible. Finally, an example for a chemically induced phase separation is given.
The Influence of the Promoter K2CO3 in Iron Catalysts on the Carbon Number Distribution of Fischer‐Tropsch‐Products
Authors: Schliebs B. , Gaube J. 
Published: July 2012

AbstractCarbon number distributions of products formed by hydrogenation of carbon monoxide over precipitated iron catalysts have been studied as a function of the K2CO3 content of the iron catalyst and of the partial pressures of carbon monoxide and hydrogen. The carbon number distribution of products formed over unpromoted catalysts can be described by a Schulz‐Flory distribution of a growth probability P1 ˜ 0.6. Products formed over alkalized iron catalysts are characterized by a bimodal Schulz‐Flory distribution of growth probabilities P1 ˜ 0.6 and P2 ˜ 0.87. The lower growth probability is nearly equal to that for an unpromoted catalyst. This result is interpreted by promoted and unpromoted sites on the catalyst surface. Formulae which describe the dependence of the growth probability and of the fractions of the superimposed two distributions on the partial pressures are given.
Chemisorption und Oberflächenreaktion in kooperativen Adsorptionssystemen
Authors: Hesse D. 
Published: July 2012

AbstractThe kinetics of propylene hydrogenation catalyzed by thermally treated supported platinum catalysts can be described by a Langmuir‐Hinshelwood mechanism. The parameter values of the resulting rate equation, however, clearly depend on the coverage of the catalyst surface. Because of the instabilities observed with this reaction, it has to be assumed that lateral interaction of chemisorbed hydrogen and chemisorbed propylene is the main reason for this parameter variation. Using the lattice‐gas model and the methods of Statistical Thermodynamics, straightforward equations are derived which take into account the influence of this interaction on chemisorption and surface reaction in binary adsystems. The usefulness of these equations for the evaluation of kinetic measurements is demonstrated by the reaction system mentioned above.
Femtosecond Optical Techniques: Application to Reaction Dynamics in Liquids
Authors: Gauduel Y. , Migus A. , Martin J. L. , Lecarpentier Y. , Antonetti A. 
Published: July 2012

AbstractWe present femtosecond techniques allowing to generate intense optical pulses from the near UV to the near infrared and their use in the monitoring of ultrafast photochemical reactions at this same time scale. Chromophores embedded in micellar solution are photoionized by femtosecond UV pulses. After the charge separation (electron), photoelectrons are shown to react with water molecules in aqueous phase of micelles and are then used to trigger and monitor the first steps of electron transfer in semi‐organized micellar solutions.
Laser Photooxidation of n‐Butane and Carbon Monoxide
Authors: Lalo C. , Masanet J. , Lempereur F. , Tardieu De Maleissye J. 
Published: July 2012

AbstractThe vibrational photoexcitation by laser of one component in a binary gaseous reactant mixture, gives the possibility to initiate bimolecular reactions under walless conditions. The present work concerns the initiation by laser of two reactions of oxidation.magnified imagen‐C4H10 and SO2 are activated by absorption of the C. W. radiation of a tunable CO2 laser. The results concerning the formation of products as a function of the irradiation time and the role of the initial pressure of reactants is discussed.
Direct Observations of Energy Transfer of Vibrationally Highly Excited Triatomic and Large Polyatomic Molecules
Authors: Hippler H. 
Published: July 2012

AbstractAverage energies 〈ΔE〉 transferred per collision between vibrationally highly excited molecules and surrounding bath gases have been measured directly by using time resolved UV absorption spectroscopy after laser excitation. The experiments have been performed with highly excited CS2, SO2, toluene, azulene, ethyl‐, and isopropyl‐cycloheptatriene respectively. A great variety of up to 60 different bath gas molecules has been investigated. The temperature has been varied from 300 K to 1000 K. For the same bath gas molecule, the effect of the molecular size of the excited molecule on the 〈ΔE〉 values has been shown to be large at low degrees of excitation while it becomes almost negligible at high excitation energies. In contrast to that the molecular size of the deactivating molecule shows always a large effect on the 〈ΔE〉 values independent from the internal energy of the “hot” molecule. The reported temperature coefficients on the 〈ΔE〉 values are small in all cases. They vary from 〈ΔE〉αT−0.5 for n‐heptane deactivating “hot” toluene or “hot” CS2 molecules, to 〈ΔE〉αT0.0 for collisions of the noble gases with “hot” toluene, and to 〈ΔE〉αT1.0 for Ne deactivating “hot,” CS2.
Determination of Rate Constants for Vibration‐to‐Vibration Energy Transfer
Authors: Teitelbaum Heshel 
Published: July 2012

AbstractThe rate equation lor vibrational relaxation of diatomic molecules is generalized by considering microscopic rate coefficients of the form kα(v + 1)e−C|ΔE|. It is shown that for most molecules of interest the rate equation reduces analytically to the form previously obtained. The consequences of its use and misuse are discussed. A prescription is given for extracting V V rate constants from rate data.
Direct Detection of Hydroxy‐Cyclohexadienyl in the Gas Phase by cw‐UV‐Laser Absorption
Authors: Fritz B. , Handwerk V. , Preidel M. , Zellner R. 
Published: July 2012

AbstractFormation of hydroxy‐cyclohexadienyl (HCHD), the product of the OH + benzene reaction, has been observed directly in the gas phase at 298 K using long‐path cw‐UV‐laser absorption at 308 nm. The absorption cross section at this wavelength is found to be (9.2 ± 2) · 10−18 cm2. The use of this technique to study directly the subsequent oxidation of HCHD by O2 is emphasized.
Nonlinear Optics at Solid State Surfaces
Authors: Dick Bernhard , Gierulski Alfred , Marowsky Gerd 
Published: July 2012

AbstractWe have studied the process of optical second harmonic generation in thin surface layers between centrosymmetric materials. The surface susceptibilities are dominated by the electronic properties of adsorbed monolayers of dye molecules. Through the appropriate choice of dye one or two electronic resonances can be employed in the process leading to dramatic enhancement of the generated signal.
Photodissociation of Negative Ions and their Clusters: CO−3 and its Hydrates
Authors: Castleman A. W. , Hunton D. E. , Albertoni C. R. , Hofmann M. , Lindeman T. G. 
Published: July 2012

AbstractPhotodissociation of the ion CO−3(H2O)n (0 ≤ n ≤ 3) is accomplished in a mass selected ion beam using an intracavity dye laser pumped with an argon ion laser. The unhydrated parent ion is observed to have a bound electronic excited state, through which absorption of a second photon proceeds to a repulsive state leading to the ejection of O− with about 20% of the available energy being partitioned into relative translation. Cluster dissociation is initiated by the same 2A1←2B1 transition from the ground to a weakly bound excited state of the core ion, leading to the loss of all water molecules within the time of observation. This is in direct contrast to collisional dissociation processes which lead largely to the loss of a single water molecule per collision. Analysis of the kinetic energy distribution of the photofragment CO−3 ions has established that an upper limit to the lifetime of the excited clusters is 20 μsec; most of the available energy is partitioned into internal motion of the CO−3 fragment rather than into relative translation of the photofragments or internal excitation of the ejected water molecules.
Thermodynamic Properties of Liquid Non‐Metallic NaNaBr Solutions
Authors: Egan J. J. , Freyland W. 
Published: July 2012

AbstractThe thermodynamic properties of molten NaNaBr mixtures were determined at 800°C for concentrations of Na up to 5 atom‐% using an emf technique with CaF2 solid electrolyte. Concentrations were controlled by the method of coulometric titration. The activity coefficient is found to pass through a maximum at 0.5 atom‐% Na. An atomic model is presented to explain the thermodynamic results of these solutions. It predicts the concentration dependence of the number of F‐centers as well as the number of F‐center associates, e. g., dimers. Calculations using the model also explain results from spectroscopic, magnetic, and electrical conductivity measurements quantitatively.
The Growth and Reduction of Duplex Oxide Films on Copper
Authors: Speckmann H.‐D. , Lohrengel M. M. , Schultze J. W. , Strehblow H.‐H. 
Published: July 2012

AbstractThe formation and reduction of anodic oxides on copper was studied by potentiodynamic polarization curves, fast potentiostatic pulse experiments and capacity measurements in alkaline solutions. Four different oxide species could be distinguished by their kinetic and capacitive behaviour: the oxide CuOx, which represents few monomolecular layers of copper oxide, formed in short periods or at low potentials, the oxides Cu2O and CuO at intermediate potentials and for longer polarization times, and a non‐defined oxidation product CuOy·zH2O at high potentials. The first 3 oxides form semiconducting films, which grow according to a high field mechanism. At intermediate potentials and at longer polarization times, the passive film consists of an inner Cu2O‐ and an outer CuO‐film, the properties of which are limited by the electronic properties. The common analysis for a high field mechanism of oxide growth can be applied to both stable oxides, taking into account the local potential difference Δϕi < Δε. The potential drop Δϕi in each of these oxides does not exceed 0.5 V. The potential drop ΔϕH in the Helmholtz layer is constant at potentials up to 1.2 V, but it increases with ε at higher potentials. The capacitive behaviour cannot be explained only by capacitors in series but parallel with diodes short circuiting the layers at an upper value of Δϕi. The oxide formation of CuOx, Cu2O and CuO takes place homogeneously all over the surface with almost constant thickness. The reduction occurs by an island mechanism for the duplex film as well as for the CuOx, film. The results are explained on the basis of a tentatively band structure model of the passive film.
Radiale Verteilung von Emissionskoeffizienten im sichtbaren und infraroten Spektralbereich in n‐Hexan‐ und Methanol‐Tankflammen
Authors: Schönbucher A. , Brötz W. , Kettler A. 
Published: July 2012

AbstractVolumetric emission coefficients of pool fires are determined from photograms and infrared radiance distributions of fires. The volumetric emission coefficients have maximum values of 0.12W/(cm3 sr) for an n‐hexane pool fire. A simplified model, based on the assumptions of the optically thin limit and non‐uniformities in temperature and species concentrations is used to compute the axisymmetric distribution of the volumetric emission coefficients from sampling probe measurements of stable species and temperatures.
Some Basic Concepts of Synergetics with Respect to Pattern Formation. Morphogenesis of Behavior
Authors: Haken H. 
Published: July 2012

AbstractMany systems in chemistry, physics, and biology can be described at different levels, in particular at a microscopic level and a macroscopic level. In synergetics an attempt is made to relate these two levels in order to understand and describe the formation of macroscopic structures (patterns) through selforganisation of interacting microscopic elements. The concept of order parameters allows us to describe patterns at a macroscopic level. The slaving principle relates the macroscopic to the microscopic level. ‐ We first present theoretic results on pattern formation of fluids and flames, and on morphogenesis. We then study a second class of phenomena which at the present level of our knowledge can be represented at the macroscopic level by means of suitable order parameters. We devise a mathematical model which will present the transition of a specific behavioral pattern of hand movement to another one. It is believed the such kind of modelling applies also to more complicated transitions between behavioral patterns, for instance when horses change the gaits. In the sense of synergetics a behavioral pattern is an outcome of a highly correlated function of microscopic elements. Though their behavior is not known explicitly the slaving principle shows us that such a high correlation is taking place and allows us to formulate equations in terms of order parameters.
Static Dielectric Permittivity and Density of Liquid Dichloromethane to 200 MPa
Authors: Diguet R. , Deul R. , Franck E. U. 
Published: July 2012

AbstractThe static dielectric permittivity, ϵ, and density, ϱ, of dichloromethane was measured from 303 to 423 K and from 10 to 200 MPa. Both quantities were determined simultaneously with the same samples in one autoclave which served as dilatometer and capacitor. The high pressure cell and auxiliary equipment are described. The ϵ‐values vary between 5.36 at 423 K and 20 MPa and 10.01 at 303 K and 200 MPa. The new ϵ‐results agree with existing literature data at 303 K but are about 2% higher than those for 323 K. Isotherms of ϵ increase almost linearly with ϱ. The density data are fitted with a modified Hayward equation. The recent Vedam‐Limsuwan‐Chen‐equation correlates ϵ and ϱ and permits to calculate ϵ or ϱ with an uncertainty lower than the experimental error. With the Onsager‐Kirkwood‐Fröhlich equation a correlation factorgclose the unity (1.1 to 1.2) is obtained.
Electrochemical Behaviour of 2,3′‐Dinitrobenzidine in N,N‐Dimethylformamide
Authors: Aravamuthan S. , Kalidas C. , Venkatachalam C. S. 
Published: July 2012

AbstractThe electrochemical reduction of 2,3′‐dinitrobenzidine (I) has been investigated in N,N‐dimethylformamide solutions. Three diffusion‐controlled polarographic waves were obtained. The first wave is due to a reversible single electron‐transfer while the second and third waves result from irreversible processes involving one and two electron‐transfers, respectively. The radical anion formed in the first step of reduction was confirmed by ESR technique. The red colour compound formed due to “ion association” after the second electron‐transfer step gives rise to a polarographic “minimum” and a “dip” in the chronopotentiogram in addition to the new “peak clusters” seen in cyclic voltammograms. A mechanism is suggested for the reduction of I leading to the formation of 2,3′‐dinitrosobenzidine.
Excess Molar Gibbs Free Energy of Solid {xKCl + (1 ‐ x)KBr} at 820 K and Partial Pressures of Its Components Determined by Knudsen Effusion‐Mass Spectrometry
Authors: Miller M. , Skudlarski K. 
Published: July 2012

AbstractExcess molar Gibbs free energy and partial pressures of the solid {xKCl + (1 ‐ x)KBr} at 820 K have been determined by Knudsen effusion‐mass Spectrometry. The parameter of the Redlich‐Kister equation for GEm has been calculated as B1 = (1944 ± 123) J mol−1. A good agreement has been found between thermodynamic data obtained from the molecular ion intensities of KCl+ and KBr+ and those obtained from dimeric ion intensities K2Cl+ (from K2Cl2) and K2Br+ (from K2Br2) assigned according to AMS/IEM method. — The results have been compared with the respective data published by other authors.
Coupled Catalytic and Autocatalytic Oxidation Reactions Linked by a Feedback Reaction Part 1. The Mechanism of the Superadditive Oxidation of p‐Phenylenediamines by Iron(III)aq and Hexacyanoferrate
Authors: Nickel Ulrich , Mao Zhou B. , Gulden G. 
Published: July 2012

AbstractThe 2‐step oxidation of some organic compounds in homogeneous aqueous solution often occurs according to an autocatalytic mechanism, because by a feedback reaction the semi oxidized form is autocatalytically increased. In presence of two different oxidants additional homogeneous catalysis can sometimes be observed, yielding a complex redox system which often causes curious experimental curves. For example p‐phenylenediamines are oxidized by iron(III)aq irreversibly, but slowly, whereas hexacyanoferrate(III) oxidizes rapidly, but reversibly. A mixture of both oxidants, however, oxidizes rapidly and irreversibly, even if the concentration of hexacyanoferrate is less than 10−8 M.
The Contributions of Intersystem Crossing and Reaction in the Removal of CH2(ã1A1) by Hydrocarbons Studied with the LMR
Authors: Böhland T. , Temps F. , Wagner H. Gg. 
Published: July 2012

AbstractThe formation of ground state CH2(X̃ 3B1)‐radicals in the collisional removal of CH2(ã1 A1) by selected hydrocarbons

with RH = CH4 (1), C2H6 (2), C3H8 (3), i‐C4H10 (4) and C2H4 (5 ) was studied in the gas phase at room temperature using Laser Magnetic Resonance (LMR). CH2(ã1A1)‐radicals wer_e generated by excimer laser photolysis of CH2CO at λ = 308 nm in the presence of varying concentrations of RH. The yields of CH2(X̃3B1) produced by intersystem crossing (1a)–(5a) were measured with the LMR. Presuming the primary quantum yield for CH2(X̃3B1) formation in the CH2CO photodissociation to be ϕ3 = 0 the branching ratios for intersystem crossing were found to be k1a/k1 = 0.17 ± 0.05, k2a/k2 = 0.19 ± 0.05, k3a/k3 = 0.24 ± 0.07, k4a/k4 = 0.28 ± 0.08, and k5a/k5 = 0.12 ± 0.06. For ϕ > 0 these values would have to be regarded as upper limits. Hence, for all hydrocarbons studied reactive quenching (1b)‐(5b) is the dominating CH2(ã1A1) removal pathway.
An Efficient Continuous Flow Technique for Investigating the Magnetic Field Dependence of Photochemical Quantum Yields
Authors: Schlenker Wolfgang , Steiner Ulrich E. 
Published: July 2012

AbstractA continuous‐flow technique has been applied to study the magnetic field effect on the photobleaching quantum yield of thionine in the reaction with aniline in reversed micellar solution and with p‐iodoaniline in methanol. The principle of the experimental technique is to irradiate the solution in a flow‐through cuvette within a magnetic field which is varied in steps and to observe optical density changes in a second cuvette connected to the first one in a flow system. Although the absolute quantum yields of the two photoreactions are below 1%, relative changes due to the magnetic field effect could be resolved with an accuracy of 1%. The observed effects on the permanent photobleaching yield closely follow the effects on the radical yield previously observed in time‐resolved experiments and are explained by the radical pair mechanism and the triplet mechanism, respectively.
Theory of Block Copolymer‐Homopolymer Blends
Authors: Noolandi Jaan 
Published: July 2012

AbstractThe theory of phase separation and microdomain formation in block copolymer‐homopolymer blends is reviewed. The calculations involve the solution of modified mean field diffusion equations for the polymer distribution functions, which are used to construct a general free energy expression, taking into account the connectedness of the blocks of the copolymer, and including changes in the conformational entropy in interphase regions, stretching of the polymer chains, enthalpic interaction terms between different chemical species, and configurational entropy terms. The effect of solid surfaces on grafted polymers is also included in the theory. As examples we discuss pure block copolymers, the use of block copolymers as surfactants in mixtures of incompatible homopolymers, and the structure of block copolymer micelles in a homopolymer matrix. A few interesting features of the equilibrium phase diagrams of blends are pointed out, and we give a preview of current theoretical work on crystalline‐amorphous block copolymers.
Electrochemical Studies on the Formation and Properties of Conducting Polymers
Authors: Heinze Jürgen , Hinkelmann Klaus , Dietrich Michael , Mortensen John 
Published: July 2012

AbstractPA can be reversibly oxidized in SO2 up to 8 mol‐% of charging, while in propylenecarbonate(PC) the discharging process becomes partly irreversible at an oxidation level of 4 mol‐% or higher. The experimental results obtained in both solvents reveal that the degradation of “p‐doped” PA in the range of its first oxidation wave is caused mainly by nucleophilic attack of the solvent. Degradation of the “n‐doped” species in a THF/Na+‐electrolyte is probably due to the attack of Na on the polymer or on the solvent. Cyclic voltammetric measurements on N‐phenyl‐carbazol show that the anodic formation of conducting polymers is due to a radical‐radical ion dimerisation (R‐R route).
Preparation and Characterization of Platinized‐Carbon Hydrogen Anodes for Alkali and Acid Fuel Cells
Authors: Shukla A. K. , Ramesh K. V. , Manoharan R. , Sarode P. R. , Vasudevan S. 
Published: July 2012

AbstractHighly dispersed platinized‐carbon hydrogen anodes are developed for utilization in alkali and acidic media power sources viz., hydrogen/air fuel cells and nickel/hydrogen batteries, by tailor making both the macro as well as micro structures of these electrodes. The optimized hydrogen anodes can withstand load currents upto 350, 800 and 500 mA/cm2 for extended periods in 6N KOH, 5N H2SO4 and 2ON H3PO4 electrolytes respectively. Characterization techniques such as photoelectron Spectroscopy, X‐ray absorption Spectroscopy, chemisorption, X‐ray diffraction, electron microscopy, electron spin resonance etc., are found to be useful in developing such electrodes. The study clearly demonstrates the significance of physico‐chemical characterization techniques in developing fuel cell electrodes.