bluuebunny/crossref_metadata_2025 huggingface dataset:
First- and Second-Line Bevacizumab in Addition to Chemotherapy for Metastatic Colorectal Cancer: A United States–Based Cost-Effectiveness Analysis
Authors: Goldstein Daniel A. , Chen Qiushi , Ayer Turgay , Howard David H. , Lipscomb Joseph , El-Rayes Bassel F. , Flowers Christopher R.
Published: February 2015

Purpose

The addition of bevacizumab to fluorouracil-based chemotherapy is a standard of care for previously untreated metastatic colorectal cancer. Continuation of bevacizumab beyond progression is an accepted standard of care based on a 1.4-month increase in median overall survival observed in a randomized trial. No United States–based cost-effectiveness modeling analyses are currently available addressing the use of bevacizumab in metastatic colorectal cancer. Our objective was to determine the cost effectiveness of bevacizumab in the first-line setting and when continued beyond progression from the perspective of US payers.

Methods

We developed two Markov models to compare the cost and effectiveness of fluorouracil, leucovorin, and oxaliplatin with or without bevacizumab in the first-line treatment and subsequent fluorouracil, leucovorin, and irinotecan with or without bevacizumab in the second-line treatment of metastatic colorectal cancer. Model robustness was addressed by univariable and probabilistic sensitivity analyses. Health outcomes were measured in life-years and quality-adjusted life-years (QALYs).

Results

Using bevacizumab in first-line therapy provided an additional 0.10 QALYs (0.14 life-years) at a cost of $59,361. The incremental cost-effectiveness ratio was $571,240 per QALY. Continuing bevacizumab beyond progression provided an additional 0.11 QALYs (0.16 life-years) at a cost of $39,209. The incremental cost-effectiveness ratio was $364,083 per QALY. In univariable sensitivity analyses, the variables with the greatest influence on the incremental cost-effectiveness ratio were bevacizumab cost, overall survival, and utility.

Conclusion

Bevacizumab provides minimal incremental benefit at high incremental cost per QALY in both the first- and second-line settings of metastatic colorectal cancer treatment.
Spirostomin, Defense Toxin of the Ciliate Spirostomum teres: Isolation, Structure Elucidation, and Synthesis
Authors: Sera Yoshihiko , Masaki Miyuki Eiraku , Doe Matsumi , Buonanno Federico , Miyake Akio , Usuki Yoshinosuke , Iio Hideo
Published: February 2015

The defense toxins, spirostomins A and B, have been isolated as a diastereomeric mixture from the ciliate microorganism Spirostomum teres. The structure of spirostomin was elucidated through a number of NMR experiments which allowed assigning the unprecedented spiro[(2,5-dimethyl-5,6,7,8-tetrahydronaphthalene-1,4-dione)-8,6′-(pyrane-2′,5′-dione)] skeleton to this natural compound. The total syntheses of the racemic spirostomins confirmed their structure and relative configurations.
Numerical Simulation of Air Entrainment for Flat-Sloped Stepped Spillway
Authors: Chakib Bentalha , Mohammed Habi
Published: February 2015

Stepped spillway is a good hydraulic structure for energy dissipation because of the large value of the surface roughness. The performance of the stepped spillway is enhanced with the presence of air that can prevent or reduce the cavitation damage. Chanson developed a method to determine the position of the start of air entrainment called inception point. Within this work the inception point is determined by using fluent computational fluid dynamics (CFD) where the volume of fluid (VOF) model is used as a tool to simulate air-water interaction on the free surface thereby the turbulence closure is derived in the k –ε turbulence standard model, at the same time one-sixth power law distribution of the velocity profile is verified. Also the pressure contours and velocity vectors at the bed surface are determined. The found numerical results agree well with experimental results.
On the Experimental Analysis of Temperature Influence on Stiffness of Reinforced Concrete Beams
Authors: Kowalski Robert , Glowacki Michal , Abramowicz Marian
Published: February 2015

The paper presents results of experimental research whose main topic was determination of stiffness reduction in bent reinforced concrete beams in two cases: when only tensioned or only compressed zone was exposed to high temperature. Twenty four reinforced concrete beams with rectangular cross-section were prepared for the experiment. Eight groups of beams were prepared in total: 2 with reinforcement ratio - 0.44 and 1.13% x 2 levels of load - 50 or 70% of destructive force ensuring the constant value of bending moment in the centre part of heated beams x 2 static schemes. Three beams were used in each group. Significant cross-section stiffness reduction was observed in beams where the tensile zone was heated. This was due to considerable elongation of the bars where the steel load elongation summed up with the free thermal strain. In beams where the compressed zone was heated the stiffness reduction was observed only after the time where the tensile zone heated cross-sections were already destroyed.
Yellow fever vaccination changes
Authors: Driver Carolyn
Published: February 2015

Carolyn Driver outlines the amendments to international health regulations and the effect on travellers
Incontinence associated dermatitis: reducing the risk
Authors: Payne Drew
Published: February 2015

Incontinence associated dermatitis can be very sore and uncomfortable. Drew Payne discusses how this condition is characterised and the best ways to prevent it occurring in the care home setting
Now we are having a ball
Authors: Daniels Sue
Published: February 2015

Sue Daniels, day manager of the Strawberry Patch Nursery in Norfolk, explains why she signed up one of her team for a dance training programme linked to the EYFS, and how her setting has benefitted as a result.
Making the connection
Authors: White Hilary
Published: February 2015

Whether you sit back and observe, or sometimes provide some sensitive encouragement, it is important that all practitioners understand how important friendships are to children's learning, wellbeing and development.
Build a nest for Easter
Authors: Chapman Ailsa
Published: February 2015

What could be easier – just three ingredients needed to make these Easter themed cakes, says Ailsa Chapman.
You are my number one
Authors: Harries Judith
Published: February 2015

One is a very special number, particularly when it denotes a favourite thing. Use these activities to explore its many forms and possibilities, and help young children to explore the concept of ‘oneness’.
Make labelling an art
Authors: White Hilary
Published: February 2015

Sticky labels come in all shapes, sizes and colours. Try the following activities with your children and discover just how versatile a simple sticky label can be.
Modification of poplar wood with glucose crosslinked with citric acid and 1,3-dimethylol-4,5-dihydroxy ethyleneurea
Authors: He Xiaoyan , Xiao Zefang , Feng Xinhao , Sui Shujuan , Wang Qingwen , Xie Yanjun
Published: February 2015

Poplar wood (Populus adenopoda Maxim) has been modified by glucose (GLC) in the presence of citric acid (CA) or 1,3-dimethylol-4,5-dihydroxy ethyleneurea (DM) as crosslinker agents. GLC can penetrate easily the wood cell walls, and after crosslinking, the cell wall is bulked. At 20% GLC concentration level, the leaching ratio of GLC incorporated into wood decreased from 73% to 15% in the presence of 10% CA or DM. The crosslinking efficiency of DM was higher than that of CA. The fixed chemicals in the cell walls caused ca. 6% permanent bulking, namely, a 43% reduction in volumetric swelling after water saturation. FTIR spectroscopy shows that GLC can be activated in the presence of a catalyst; however, the reaction of GLC with a wood polymer is very limited. Scanning electronic microscopy (SEM) reveals that some of the chemicals remained located in the cell lumens. The findings demonstrate that GLC alone is not efficient, but joint treatment of GLC with crosslinkers is a feasible way of wood modification.
Pilot-scale demonstration of SPORL for bioconversion of lodgepole pine to bioethanol and lignosulfonate
Authors: Zhou Haifeng , Zhu J. Y. , Gleisner Roland , Qiu Xueqing , Horn Eric , Negrón José
Published: February 2015

The process sulfite pretreatment to overcome recalcitrance of lignocelluloses (SPORL) has been the focus of this study. Pilot-scale (50 kg) pretreatment of wood chips of lodgepole pine (Pinus contorta Douglas ex Loudon) killed by mountain pine beetle (Dendroctonus ponderosae Hopkins) were conducted at 165°C with a dilute sulfite solution of pH 2 for bioconversion to ethanol and lignosulfonate (LS). The pretreatment duration was optimized in laboratory bench scale experiments with a certain severity based on a combined hydrolysis factor (CHF). The sodium bisulfite loading was 8% and the liquor to wood ratio 3. The pretreated solids were disk milled together with the spent liquid and the resultant slurry with a 25% solids content was directly (without detoxification) submitted to a simultaneous enzymatic saccharification and fermentation (SSF) with Saccharomyces
cerevisiae YRH400 at cellulase loading of 35 ml kg-1 of untreated wood. At solids loading of 20%, the alcohol yield was 288 l t-1 wood (with a final concentration of 52.2 g l-1), which corresponds to a 72.0% theoretical yield based on total glucan, mannan, and xylan. The LS from SPORL was highly sulfonated and its molecular weight was lower than that of a purified commercial softwood LS, and therefore it has a high potential as a directly marketable co-product.
Hormones and the blood-brain barrier
Authors: Hampl Richard , Bičíková Marie , Sosvorová Lucie
Published: February 2015

Hormones exert many actions in the brain, and brain cells are also hormonally active. To reach their targets in brain structures, hormones must overcome the blood-brain barrier (BBB). The BBB is a unique device selecting desired/undesired molecules to reach or leave the brain, and it is composed of endothelial cells forming the brain vasculature. These cells differ from other endothelial cells in their almost impermeable tight junctions and in possessing several membrane structures such as receptors, transporters, and metabolically active molecules, ensuring their selection function. The main ways how compounds pass through the BBB are briefly outlined in this review. The main part concerns the transport of major classes of hormones: steroids, including neurosteroids, thyroid hormones, insulin, and other peptide hormones regulating energy homeostasis, growth hormone, and also various cytokines. Peptide transporters mediating the saturable transport of individual classes of hormones are reviewed. The last paragraph provides examples of how hormones affect the permeability and function of the BBB either at the level of tight junctions or by various transporters.
Thymoquinone ameliorates NLRP3-mediated inflammation in the pancreas of albino Wistar rats fed ethanol and high-fat diet
Authors: Periyanayagam Suguna , Arumugam Geetha , Ravikumar Aruna , Ganesan Vijaiyan Siva
Published: February 2015

Background: Inflammasomes are protein complexes that mediate the process of inflammation and tissue injury by regulating the level of cytokine production. Pancreatitis is a major gastrointestinal disorder characterized by painful inflammation in the pancreas. The aim of this study was to evaluate whether thymoquinone (TQ) exerts anti-inflammatory activity by influencing the expression of the apoptosis-associated speck-like protein (ASC) complex of NOD-like receptor pyrin domain containing 3 (NLRP3) inflammasomes in rats subjected to experimental pancreatitis.

Methods: Male albino Wistar rats were randomly separated into four groups. Rats in groups 1 and 2 were fed with a normal diet for 90 days, and rats in groups 3 and 4 were administered with ethanol (EtOH) 8–12 g/kg/day orally and fed with a high-fat diet (HFD) for 90 days. In addition, rats in groups 2 and 4 were administered with 100 mg/kg body weight of TQ from the 31st day. The serum lipase (L)/amylase (A) ratio; the oxidative stress markers; the GSH/GSSG ratio; the mRNA expression of ASC, caspase-1, IL-1β, IL-18, and TNF-α; and the protein expression of ASC and caspase-1 in the pancreas were assessed.

Results: We observed a significant increase in the serum L/A ratio and oxidative stress, a decrease in the GSH/GSSG ratio, and a GST activity in EtOH- and HFD-fed rats. The mRNA expression of IL-1β, IL-18, and TNF-α was significantly reduced in TQ-coadministered rats than that in EtOH- and HFD-fed rats. The upregulation of mRNA and the protein expression of ASC and caspase-1 were significantly reduced in TQ-coadministered rats.

Conclusions: TQ exerts the anti-inflammatory activity probably by downregulating the ASC expression to minimize the maturation of proinflammatory cytokines.
Explicit formula for the solution of the phaseless inverse
scattering problem of imaging of nano structures
Authors: Klibanov Michael V. , Romanov Vladimir G.
Published: February 2015

Imaging of nano structures is necessary for the quality control in their
manufacturing. In the case when X-rays probe the medium, only the modulus of
the complex valued scattered wave field can be measured. The phase cannot be
measured. In the case of the Born approximation, we obtain an explicit
reconstruction formula for the unknown coefficient from the phaseless
scattering data.
Associations between IGF-I, IGF-binding proteins and bone turnover markers in prepubertal obese children
Authors: Gajewska Joanna , Klemarczyk Witold , Ambroszkiewicz Jadwiga , Szamotulska Katarzyna , Chełchowska Magdalena , Weker Halina
Published: February 2015

: To assess the relationships between components of the growth hormone axis, body composition, and bone markers in obese children.

: We determined the levels of bone alkaline phosphatase (BALP), C-terminal telopeptide of type I collagen (CTX-I), insulin-like growth factor-I (IGF-I), and IGF-binding proteins (IGFBPs) by immunoenzymatic methods, and body composition by dual-energy X-ray absorptiometry in 45 obese and 20 non-obese children.

IGF-I and functional IGFBP-3 levels, IGF-I/total IGFBP-3, and functional IGFBP-3/total IGFBP-3 molar ratios were significantly higher in obese patients than in controls. Multivariate regression analysis in obese patients showed significant associations of BALP with IGF-I (p=0.047) and percent of body fat mass (p=0.002).

The relationship of IGF-I and functional IGFBP-3 to BALP may support the concept of IGF-I influence on accelerated bone formation process in obesity. Moreover, IGF-I and percentage of body fat mass may be significant predictors of BALP in obese during the prepubertal period.
Exact solutions for the fractional differential equations by using the first integral method
Authors: Aminikhah Hossein , Sheikhani A. Refahi , Rezazadeh Hadi
Published: February 2015

In this paper, we apply the first integral method to study the solutions of the nonlinear fractional modified Benjamin-Bona-Mahony equation, the nonlinear fractional modified Zakharov-Kuznetsov equation and the nonlinear fractional Whitham-Broer-Kaup-Like systems. This method is based on the ring theory of commutative algebra. The results obtained by the proposed method show that the approach is effective and general. This approach can also be applied to other nonlinear fractional differential equations, which are arising in the theory of solitons and other areas.
Analytical Solutions for Rumor Spreading Dynamical Model in a Social Network
Authors: Fallahpour R. , Chakouvari S. , Askari H.
Published: February 2015

In this paper, Laplace Adomian decomposition method is utilized for evaluating of spreading model of rumor. Firstly, a succinct review is constructed on the subject of using analytical methods such as Adomian decomposion method, Variational iteration method and Homotopy Analysis method for epidemic models and biomathematics. In continue a spreading model of rumor with consideration of forgetting mechanism is assumed and subsequently LADM is exerted for solving of it. By means of the aforementioned method, a general solution is achieved for this problem which can be readily employed for assessing of rumor model without exerting any computer program. In addition, obtained consequences for this problem are discussed for different cases and parameters. Furthermore, it is shown the method is so straightforward and fruitful for analyzing equations which have complicated terms same as rumor model. By employing numerical methods, it is revealed LADM is so powerful and accurate for eliciting solutions of this model. Eventually, it is concluded that this method is so appropriate for this problem and it can provide researchers a very powerful vehicle for scrutinizing rumor models in diverse kinds of social networks such as Facebook, YouTube, Flickr, LinkedIn and Tuitor.
Stochastic Properties of a One-Dimensional Discrete Ginzburg-Landau Field
Authors: Jaspers M. , Schattke W.
Published: February 2015

Starting from a master equation for a discrete order parameter a dynamical model is set up via mean-field approximation in the Fokker-Planck equation. The time evolution of some mean values is calculated numerically, showing two transitions with characteristic slowing down of the relaxation time
Der Einflufi der Phononenmitfiihrung auf den Elektrotransp in Metallen / Influence of Phonon Drag on the Eledromigration in Metals
Authors: Bohn H.-J. , Simon G.
Published: February 2015

For the driving force of electromigration on an impurity atom in a metal usually one takes into consideration only the direct influence of the electrical field and the collisions with electrons. It is shown that the contribution of the phonon drag to the driving force may in some cases exceed the contribution of the electrons considerably.

A system of Boltzmann transport equations for the distribution functions of electrons, phonons and impurity atoms is set up and solved in linear approximation. As a result of the theory the "effective" charge of the impurity atoms - that is that quantity, which is usually obtained by experimental investigations - can be split up into two additive contributions from electron and phonon collisions. The effective charge can be expressed through microscopic quantities. The magnitude of the effective charges agrees rather well with experiment, but not their dependence on temperature
Topological Resonance Energy of Very Large Benzenoid Hydrocarbons
Authors: Gutman Ivan
Published: February 2015

An approximate expression is obtained for the resonance energy of benzenoid hydrocarbons. The resonance energy is shown to depend in a simple manner on the number of six-membered cycles and on the number of Kekule structural formulae of the molecule. By this approach, the resonance energies of very large benzenoid hydrocarbons can be determined.
Lattice Vibration Spectra XXIV*. Far-Infrared Reflection Spectra, Optical and Dielectric Constants, and Effective Charges of the Pyrite Type Compounds FeS2, MnS2, MnSe2, and MnTe2
Authors: Lutz H. D. , Kliche G. , Haeuseler H.
Published: February 2015

From the far-infrared reflection spectra of the pyrite type compounds FeS2, MnS2, MnSe2, and MnTe2 we determined the TO and LO phonon frequencies at wave vector | q | ≈ 0 by both Kramers-Kronig analysis and classical oscillator fit method. In the case of MnSe2 and MnTe2 we found for the first time all five group-theoretically allowed reststrahlen bands. The phonon frequencies obtained from both single crystal and pressed pellet reflection measurements do not show any significant differences. The calculated optical and dielectric constants however are strongly affected by the surface quality of the sample. Effective ionic charges (Born effective charge, Szigeti charge) were calculated from the experimentally determined TO/LO splittings. They demonstrate an increasing ionicity in the order FeS2<MnTe2<MnSe2<MnS2.
Fluorescence and Absorption Spectra of Phenylazopyrazolone Dyes
Authors: Nikolov Peter , Fratev Filip , Stoyanov Stefan , Polansky Oskar E.
Published: February 2015

The absorption and fluorescence spectra of some arylazopyrazolone dyes have been investigated. The emission is assigned to their hydrazone form. A very good linear correlation is obtained between the σ Hammett constants and the differences of the absorption maxima of the hydrazone form and the anion. Quantum chemical calculations indicate to a charge migration upon exci­tation.

The electron donor substituents cause bathochromic and hypsochromic shifts in the absorption and in the fluorescence maxima resp., while the acceptor substituents shift bathochromically both maxima. All compounds studied except the p-N(CH3)2 derivative show an anomalously large Stokes shift in nonpolar solvents.
NH4
+ Ion Motions in Some Ammonium Salts
Authors: Köksal Fevzi
Published: February 2015

Spin-lattice relaxation times of protons in polycrystalline (NH4)2SO4, (NH3OH)2SO4, (NH4)2HPO4, NH4VO3, (NH4)2CrO4, (NH4)2C2O4 • H2O and NH4HF2 salts were measured over the temperature range 100-430 K. The double minima in T1 for the first three compounds were attributed to the nonequivalent NH4
+ ions in the unit cells. In NH4VO3, the double minima were attributed to the reorientations about two and three fold axes. However only one minimum in T1 was observed for (NH4)2CrO4, (NH4)2C2O4 • H2O and NH4HF2 and the relaxation mechanisms for the first three compounds were attributed to random reorientations of NH4
+ ions. The experimental results are in good agreement with the calculated values by using the existing theoretical expressions. The discrepancies between experimental and calculated values for (NH4)2HPO4 and NH4HF2 at low temperatures were attributed to the tightness of the hydrogen bonding at those temperatures
Comparative Dynamics of Atmosphere-Ocean-Models within the Description of the Perturbed Global Carbon Cycle
Authors: Siré E. O. , Kohlmaier G. H. , Kratz G. , Fischbach U. , Brohl H.
Published: February 2015

For a certain class of ocean models describing the exchange of inorganic carbon between the atmosphere and the surface layer of the ocean as well as between the surface layer and the deep sea the dynamical airborne fraction is evaluated analytically under the assumption that the growth rate of the atmospheric source term (fossil fuel plus net biogenic carbon input into the atmosphere) is slowly variable with time. Each of these models exhibits a certain uptake capacity of the deep ocean which is quantified. Considerations are made as to whether the terrestrial biota are to be regarded as a source or a sink for additional atmospheric CO2 depending on the modelling of the deep ocean. It is shown that a global one-dimensional box-diffusion ocean model with a depth dependent eddy diffusivity K(z) - K(0) exp[-z/z*], with an adjustable parameter set {K(0), z*}, provides a fairly well fit to the prebomb 14C ocean distribution and to an appreciable net biogenic carbon transfer into the atmosphere. The range of future atmospheric CO2 partial pressures is estimated for a given fossil input
Correlation in the Ground State of He Atom
Authors: Saha Subal Chandra , Sengupta Sankar
Published: February 2015

It is possible to reproduce the entire results of Pekeris et al. of different atomic parameters for the He atom by introducing (ll) type correlation in a self consistent variation perturbation procedure using the Hartree-Fock (HF) wavefunction as the zero-order wavefunction
Characterization of the High Temperature Form of Fe2(MoO4)3
Authors: Gur'ev A. V. , Flor G. , Marini A. , Massarotti V. , Riccardi R.
Published: February 2015

Ferric molyhdate in its high temperature orthorhomhic phase has been characterized by conductometric and thermogravimetric measurements.

In the temperature range 793-973 K the compound can exist with O2 and MoO3 deficiencies.

Defect models are proposed which can explain the experimental results: while a majority defect pair constituted by (Vo2-,e') seems to be valid at T = 793 K, two majority defect pairs (Vo2-, e'; V6'
Mo, VO
2') are taken as possible at T = 873 K
Thermodynamische Untersuchungen an Menshutkin-Komplexen II. Schmelzenthalpien und -entropien von Menshutkin-Komplexen / Thermodynamic Investigations of Menshutkin-Complexes. II. Melting Enthalpies and Entropies of Menshutkin Complexes
Authors: Perkampus H.-H. , Sondern Chr.
Published: February 2015

The melting enthalpies and entropies of 24 Menshutkin complexes composed of 2SbCl3 and aromatic compounds were measured by calorimetric methods. The relatively large values of these thermodynamic data can be explained under the assumption of a dissociation of the complexes during melting. The association enthalpy can be estimated by separating the melting process into two steps
Force Field Calculation with a Top Desk Calculator
Authors: Ali Jafar H. , Shanshal Muthanna
Published: February 2015

A modified “Consistent Force Field ” method is described in which the energy minimization is carried out according to the Murtagh-Sargent method rather than the Newton-Raphson method and the number of non-bonded interactions is reduced to interactions between atoms separated by three bonds at the most. The smaller number of interaction terms allowed the programming of the method for a desk top calculator (HP-9810). Calculations are reported for a number of aliphatic molecules
Chemische Oszillationen bei der Methanoloxidation an einem Pd-Trägerkatalysator / Chemical Oscillations of the Methanol-Oxidation on a Pd-Supported Catalyst
Authors: Jaeger N. I. , Plath P. J. , Raaij E. van
Published: February 2015

A periodic reaction was observed for the total oxidation of methanol to CO2 and H2O on a Pd-supported catalyst. By measuring the temperature oscillations of the catalyst and the corresponding product distribution the phenomenology could be correlated with a chemical reaction scheme. The reaction scheme is based on the nonmonotonic behavior of the pressure-concentration relationship of the Pd-H system
Neutron Diffraction with the Metallic Glass Ni81B19 Using Isotopic Substitution
Authors: Lamparter P. , Sperl W. , Rainer-Harbach G. , Steeb S.
Published: February 2015

In the field of structural research of metallic T80M20-glasses (T = Fe, Co, Ni; M = B, P) at the moment large interest exists in the determination of the so called partial structure factors Smn, especially of the structure factor SMM which is determined by the arrangement of the met-alloid atoms. Since the mathematical evaluation of SMM from three measured total structur factors is rather uncertain, in [1] a method was proposed for the direct measuring of SBB in Ni81B19, the experimental realization of which will be reported in the present paper
Calculation of Vibrational Spectra for Surface Atoms: FCC Transition Metals
Authors: Masuda K.
Published: February 2015

A (self-consistent) tight-binding type electronic theory is used to calculate the atomic relax­ ation and force constants between atoms near the (001) surface of fee transition metals (Ni, Pd and Pt). Assuming the Born-Mayer potential for the short-range core repulsion energies, we have derived simple analytic expressions for the force constants near the surface. We then calculate the local vibrational spectra and Debye parameters for the surface atoms, employing the recursion method originally introduced by Haydock et al. for the electronic structure calculation of solids. It is shown that the inclusion of electronic effects (electronic rearrangement and surface relax­ation) is important for the vibration of surface atoms.
Refractivity of Molten Nitrates and Chlorides: Binary Mixtures Containing Cesium Ions
Authors: Uchiyama Yohji , Karawacki Ernest
Published: February 2015

By using an interferometric technique, the refractive index of some molten salt mixtures containing Cs+ ions was measured with high accuracy: (Li-Cs)NO3, (Na-Cs)NO3, (Ag-Cs)NO3, (Li-Cs)Cl, and also pure RbCl. The isotherms of molar refractivity show a small negative deviation from additivity in the (Li-Cs)NO3 and (Li-Cs)Cl systems and a positive deviation in the (Ag-Cs)NO3 mixture. A tentative attempt was made to relate the excess molar refractivities with the absorption bands of the ions.
Effects of Pressure and Temperature on the Fluorescence Quantum Yield of N-Methylacridone in Solution Interpreted in Terms of the Eyring Transition-StateTheory
Authors: Brauer H.-D. , Schmidt R. , Hammerich B.
Published: February 2015

The influence of temperatur and pressure on the fluorescence quantum yield of N-methylacridone (9,10-dihydro-9-oxo-10-methyl-acridine) in toluene in the range of 283-313 K and 1 bar to 2.5 kbar, respectively, has been investigated. Treatment of the data in terms of the Eyring transition-state theory leads to a consistent interpretation of the observed effect. The unusually large increase of the quantum yield with increasing pressure is attributed to a positive volume of activation, ⊿V≠, for the thermally activated S1-T2 intersystem crossing which is known to be the only deactivation process (of the Si-state) competing with fluorescence. Comparison of the values for ⊿H≠, the activation enthalpy of this process, determined at various pressures, indicates a decrease in ⊿H≠ at elevated pressures. Since ⊿H≠ can be associated with the S1-T2 energy gap involved in intersystem crossing, this result further confirms the conclusion that the change in Franck-Condon factors alone cannot account for the decrease in the intersystem crossing rate with increasing pressure.
T Torque on a Small Particle in a Nonhomogeneous Monatomic Gas
Authors: Vestner H. , Halbritter J.
Published: February 2015

The torque a particle experiences in a monatomic gas in non-equilibrium is calculated with the method Waldmann originally used to compute the force. For a particle which is much smaller than the mean free path in the gas this method involves the following two essential steps:

i) with the help of a boundary condition the torque is expressed by the velocity distribution function of the gas atoms approaching the particle;

ii) this undisturbed distribution function is approximated by a moments-expansion, restricted here to thirteen moments.

In the resulting expression for the torque the pressure tensor and the local vorticity in the gas occur. The geometrical factors are given for particles shaped as spheroids, cylinders and spherocylinders
Birefringence in the Boundary Layer of a Rarefied Heat Conducting Gas
Authors: Oudeman P. , Korving J. , Knaap H. F. P. , Beenakker J. J. M.
Published: February 2015

In a heat conducting gas of diatomic molecules enclosed between parallel plates, the second rank tensor polarization of the rotational angular momenta can be shown to be nonzero in a boundary layer near the plates, a few mean free paths thick. This phenomenon can be experimentally studied by measuring the birefringence of the boundary layer. Although the predicted effects are very small (An of the order of 10-14), the existence of this effect is clearly demonstrated and qualitative results are obtained for N2, CO and HD
A Topological Approach to the Predicting of the Electron Energy Characteristics of Conjugated Infinite Polymers. II. PPP-Calculations
Authors: Bonchev D. , Mekenyan Ov.
Published: February 2015

A topological extrapolation procedure is applied (within the PPP-method) to the predicting of the mean π-electron energy and energy gaps of 10 infinite polymers composed of benzenoid units
A A Tjopological Approach to the Predicting of the Electron Energy Characteristics of Conjugated Infinite Polymers. III. The Influence of Some Structural Modifications of Polymers
Authors: Bonchev D. , Mekenyan Ov.
Published: February 2015

The influence of acyclic conjugated branches on the π-electron energy and energy gaps of infinite polymers containing benzene rings is studied applying a graph-theoretical extrapolation scheme. It is found that methylene branches strongly reduce the energy gap of the unmodified polymers
Correlations between the Ground State and the Triplet State Character Orders of Benzenoid Hydrocarbons
Authors: Bräuchle Chr. , Voitländer J. , Vogler H.
Published: February 2015

The relative localization of the n-conjugation of benzenoid hydrocarbons in the ground state So and the lowest excited triplet state Ti is described by means of character orders. For molecules with the same unmber of electron sextets a linear correlation could be found between the mean character orders of So and Ti indicating the similarities in the electron distribution of these states. The relevance of this similarity for an earlier explanation of the zero-field splitting in Ti is given
Microwave Double Resonance Investigation of Rotational Relaxation of Methyl Iodide-d3
Authors: Schrepp W. , Dreizler H.
Published: February 2015

For a study of rotational relaxation of methyl iodide, CD3I, the method of microwave modulated four-level double resonance has been used. The manifold of the J = 1,2 and 3 levels has been investigated and the η-values have been determined. An experimental procedure to overcome disturbancies produced by the dynamic Stark-effect is described. The sign of the η-values is interpreted in terms of first order dipole and quadrupole type rate constants. The experimental results are in accordance with theoretical results of Rabitz et al. Further a derivation of collisional selection rules for molecules with a nuclear quadrupole moment is given
Thermoreversiblej Photo Valence Isomerization of 9-t-Butylanthracene to its 9,10-Dewar-Isomer
Authors: Dreeskamp H. , Jahn B. , Pabst J.
Published: February 2015

On excitation the first excited singlet state (1La), 9-t-butylanthracene (1) reacts in dilute (10-6-10-3 mole · 1-1) heptane solution with a quantum yield of Φ = 0.016 ± 0.002 to its valence isomer 1-t-butyl-dibenzo-2,5-bicyclo-(2,2,0)-hexadiene (9-t-butyl-9,10-Dewar-anthracene) (2). UV-spectroscopic and 1H-NMR-data of educt and product confirm the proposed isomerization. The reaction is thermoreversible. The first order rate constant of the back reaction was determined in the temperature range of 293 K to 343 K and yielded the activation enthalpy ΔH≠ = 91 ± 3 [kJ · mole-1] and the activation entropie ΔS≠ = - 25 ± 8 [J · mole-1 · K-1] in heptane and 94 ± 3 [kJ · mole-1] and - 17 ± 8 [J · mole-1 · K-1] in ethanole
Experimental and Quantum Mechanical Investigation on Dipole Moments of Some Oxazole Derivatives in Lowest Singlet Excited State
Authors: Gryczyński I. , Jung Ch. , Kawska-Kubicka H.
Published: February 2015

Electric dipole moments in the ground and lowest singlet excited state of four axazole derivatives were calculated theoretically using the PPPCI method, and determined experimentally on the basis of solvatochromic shifts in the electronic spectra
Zur Schwingungsstruktur der Shpolskii-Spektren von Naphthalin in n-Pentan bei 77 K (Fluoreszenz, S0 → S1- und S0 → S2-Absorption) *
Authors: Bałuk P. , Kawski A. , Kałas M.
Published: February 2015

The fluorescence, So -> Si-and So -> S2-absorption spectra of naphthalene in n-pentane at 77 K were measured. The Franck-Condon-Factors are evaluated using equilibrium geometries and normal coordinates of the molecule in the ground (So), in first (Si) and secound (S2) excited singlet states which were calculated by the QCFF/PI-method and by taking the Dushinskii-Efekt into acount. These results were compared with experimentally determined frequencies and estimated relative intensities.
Semiempirical Calculations of Valence Force Constants in C2X4, C3X4 and C4X4 Compounds
Authors: Fleming G. Díaz , Kosmus W. , Kalcher K.
Published: February 2015

e m ie m p iric a l C a lc u la tio n s o f V a le n c e F o rc e C o n s ta n ts in C 2X 4 , C3X4 a n d C 4X 4 C o m p o u n d s Valence force constants were calculated for C2X4, C3X4 and C4X4 (X = H, F, Cl, Br) with a point charge model using CNDO data. The magnitude of the valence force constants is discussed in terms of the polarization of the static electron distribution.
A Heisenberg Ferromagnet With Biquadratic and Dipol-octupol Interactions
Authors: Ba̮k Z.
Published: February 2015

A Heisenberg S - 3/2 ferromagnet with isotropic biquadratic exchange and dipole-octupol coupling is discussed. The conditions for the exact ferromagnetic ground state are derived. The thermodynamical behaviour in the molecular field approximation is discussed. Collective excitation spectra and the 1/z correction to the free energy are found.
Analysis of the Microwave Spectrum of Tricarbon Oxide Sulfide, 0 = C = C = C = S, in Highly Excited Bending States
Authors: Winnewisser Manfred , Peau E. Walter , Yamada Koichi
Published: February 2015

In The microwave spectrum of tricarbon oxide sulphide (3-thioxo-l,2-propadiene-l-one), 0=C= C=C=S, has been measured in the frequency range from 8 to 40 GHz and includes vibrational satellite lines arising from the vibrational manifold of the lowest-lying doubly-degenerate bending mode i>7. The method of analysis followed the theory of rotation-vibrational interaction as devel-oped by Nielsen and Amat. The spectroscopic constants B v and D v as well as several vibration-rotational constants for each vibrational state vy = 0 to 7, = 1 and vq = 1 were determined with the aid of a newly written least squares program. The program structure relies on the cor-relation of the symmetry classification of energy levels in linear and bent molecules, and follows closely the analysis of asymmetric rotor spectra. From the «»vibrational spectrum of C3OS in excited states of vy up to t'7 — 7 and 1 — 6 the sign and magnitude of the effective vibrational anharmonicity constant xi t i t were determined. The interpretation of these results yields the infor-mation that in C3OS the potential function describing the two-dimensional oscillator of the vj bending mode is very harmonic and does not contain a perturbing hump. The dynamic behaviour of C3OS, a classical example of a linear molecule, is thus in sharp contrast to the quasilinear be-haviour of C3O2 •
Schwingungsspektren der Tetraphosphortetrasulfide
Authors: Bues W. , Somer M. , Brockner W.
Published: February 2015

The solid-state i.r. and Raman spectra of the crystalline tetraphosphorus tetrasulphides -α -P4S4 and β-P4S4 - and the Raman spectrum of the α-P4S4 melt have been recorded. The observed frequencies of α-P4S4 were tentatively assigned to P4S4 molecules of the cradle type, possessing D2d symmetry. An assignment of the β-P4S4 frequencies to a cage-like P4S4 unit with Cs symmetry is proposed and based on comparison with similar P-S-compounds such as P4S3 and α-P4S5. All the tetraphosphorus tetrasulphides decompose during melting into P4S3, P4S7 and β-P4S6.
Schwingungsberechnungen der käfigstrukturierten Moleküle P4Se3 , AS4S3, As4Se3 und PAs3S3 / Molecular Vibration Analysis of the cage-like Molecules P4Pe3, As4S3, As4Se3 and PAs3S3
Authors: Brockner W. , Somer M. , Cyvin B. N. , Cyvin S. J.
Published: February 2015

Abstractn

The P4Se3, As4S3, As4Se3 and PAs3S3 molecules are supposed to have a cage-structure of the C3V symmetry. Normal coordinate analyses for these molecules were performed, based on a very simple initial force field transferred from P4S3. The force field was refined by adjusting the symmetry force constants to fit exactly observed frequencies. The force fields were used to calculate the mean amplitudes of vibration and Coriolis coupling constants. The standard thermodynamical functions from spectroscopic data are also given.
Photocatalytic Splitting of Liquid Water by n-TiO2 Suspension
Authors: Vonach Waltraud , Getoff Nikola
Published: February 2015

By illumination (λ>300 nm) of a suspension of n-TiO2 (grain size ≦0.06 mm, 3 to 15 mg/ml) in aqueous acid solutions, containing 10-3 mol · dm-3 Ce4+ -ions an enhanced evolution of oxygen is observed. Its yield is dependent on the amount of TiO2 in the suspension and on the temperature. Using n-TiO2 suspended in diluted sulfuric acid, hydrogen and oxygen were produced in a ratio of about 2: 1. In both systems n-TiO2 is acting as an efficient electron donor. For the explanation of the processes probable reaction mechanisms are proposed.
Dipole Moments and Polarizabilities of Benzophenones Estimated from Spectroscopic Measurements
Authors: Stori M.
Published: February 2015

The effect of microenvironment on the absorption spectra of benzophenone and its aminoderivatives in n-heptane/n-butanol and n-heptane/benzene mixtures was investigated. The local dielectic constants, the composition of the solvatation shell, the Onsager cavity radius "a" and the values of a/a3 (α - the polarizability of solute molecules) have been evaluated from the spectral shifts.
On the Order-Disorder Phase Transformation of Anilinium Halides.
Authors: Fecher Gerhard , Weiss Alarich , Heger Gernot
Published: February 2015

The crystal structure of the low temperature phase of anilinium bromide, C6H5NH3
⊕Br⊖, was studied by neutron diffraction at T = 100 K. The refinement supports an ordered structure. The structures of the low and high temperature phases are compared and the mechanism of the phase transformation is discussed.
Influence of Environment on the Electronic Spectra of Donor-Acceptor-Substituted trans-Stilbenes in Solvent Mixtures
Authors: Kawski A. , Ostrowska B. , Ston M.
Published: February 2015

The effect of n-heptane and n-butanol mixtures upon the absorption and fluorescence spectra of donor-acceptor-substituted trans-stilbenes is investigated. The electronic-vibration spectra of these compounds depend upon the magnitude of the electric dipole moments in the ground and excited states, upon the relation between the mean lifetime τf
w and the time of dielectric relaxation τR, and upon the environment around the solute molecule.
Ultrasonic Studies in N-(p-n-butoxybenzylidene)-p-n-butylaniline
Authors: Rao J. V. , Murty C. R. K.
Published: February 2015

The ultrasonic velocity in the SG(SH), SB, SA, Nc , N0 and isotropic liquid phases of N-(p-n-butoxybenzylidene)-p-n-butylaniline (BBBA) has been measured as a function of temperature. A transition in the nematic phase seems to indicate the existence of an ordinary nematic and a cybotactic nematic phase. The transition SG-SB has been found for the first time with the ultra-sonic velocity method. The adiabatic compressibility βad and the molar sound velocity Rn (Rao number) have been determined using the experimental density and ultrasonic velocity.
Thermische Oszillationen und chaotisches Verhalten bei der Oxidation von Kohlenmonoxid an Pd-Kristalliten im Inneren einer Zeolithmatrix / Thermal Oscillations and Chaotic Behaviour at the Oxidation of CO on Pd Crystallites within a Zeolite Matrix
Authors: Jaeger N. I. , Möller K. , Plath P. J.
Published: February 2015

The oxidation of CO on a Pd supported catalyst was investigated in a differential reactor. The catalyst consisted of a homogeneous distribution of Pd crystallites (∅ =8 - 10 nm) within a zeolite matrix (Faujasite type X). Depending on the temperature of the reactor and the CO con-centration in the feed gas bistable, periodic and chaotic behaviour of the temperature of the catalyst bed could be observed.
Determination of the Partial Structure Factors of the Metallic Glass Fe80B20
Authors: Nold E. , Lamparter P. , Olbrich H. , Rainer-Harbach G. , Steeb S.
Published: February 2015

By X-ray diffraction and neutron diffraction using the isotopic substitution method, the partial structure factors /SFeFe, SFeB, and SBB well as SNN, SCC, and SNC were determined for the metallic glass Fe80B20. The Fourier-transforms yielded the pair correlation functions Gij from which the atomic distances and the partial coordination numbers were calculated. The partial coordination numbers are in good agreement with those of the metastable Fe3B-phase, which is the first crystallization product formed during annealing of the metallic glass Fe80B20. The chemical short range order parameter amounts to 100%, thus indicating perfect chemical order.
Detection of the Infrared Spectrum of Cyanobutadiyne, HC5N
Authors: Yamada Koichi , Winnewisser Gisbert
Published: February 2015

The CN stretching band, ν2, of cyanobutadiyne has been detected by a tunable diode laser spectrometer in the wavenumber range from 2250 to 2260 cm-1. The P-and R-branch transitions, up to P(77) and R(75), of the fundamental band were identified and measured with the accuracy of 0.001 cm-1. The band origin was obtained to be 2256.12406(13) cm-1. The rotational and centrifugal distortion constants in the excited vibrational state, B′ and D′, were also determined.
Activity Coefficients and Excess Molar Gibbs Functions of Liquid Alkali Halide + Silver Halide Mixtures at Varying Temperature and Composition
Authors: Richter J. , Conradt R. , Becker R.
Published: February 2015

In certain temperature ranges, the e.m.f. of binary molten salt concentration cells without transference can be described by a mole fraction expansion with three constants depending linearly on temperature.

With the six constants it is possible to calculate the activity coefficients, the thermodynamic factor, and the excess molar Gibbs function of liquid alkali halide + silver halide mixtures at given temperatures and compositions. The precision of the representation corresponds to an accuracy in the e.m.f. data of 0.5 mV to 1.2 mV.
Photo-Electro-Luminescence of ZnS: (Cu, Ce) and ZnS: (Ag, Ce) Phosphors
Authors: Tripathi L. N. , Chaubey B. R. , Mishra C. P.
Published: February 2015

The enhancement and quenching of the prominent emission bands at 4700 Å and 5300 Å of ZnS: (Cu, Ce) and 4600 Å and 5200 Å of ZnS: (Ag, Ce) on single or simultaneous application of a sinusoidal electric field and 3650 Å UV radiation have been studied.
Iteration-Perturbation Theory of Covalent Bonding in Crystals
Authors: Krasko Genrich L.
Published: February 2015

An iteration-perturbation approach is suggested which enables the calculation of the binding energy and equilibrium lattice parameters of non-metallic crystals. Making use of the single­band-gap model, the selfconsistent Schrödinger equation can be solved in terms of the effective matrix elements, W(g)′s, which, in general, satisfy the set of nonlinear equations. The latter are solved for those reciprocal lattice vectors g for which the perturbation theory requirements are violated. Since the matrix elements of ion-electron interaction are not small for some g’s the screening of all the interactions in the crystal is not linear. The exchange-correlation contributions both in the screening and in the total energy are accounted for by means of the Kohn-Sham density-functional-formalism. A charge transfer is shown to result in excluding part of the electrons from the screening processes. The theory allows also for the possibility of a strongly non-homogeneous electron density distribution in the crystal.

The results of the calculation for magnesium hydride MgH2 are presented in paper II.
Theory of Rotational Motion of Prolate Luminescent Molecules in Solution
Authors: Alicki R. , Alicka M. , Kawski A.
Published: February 2015

On the ground of a generalized equation for rotational diffusion which takes the inertial effect into account, an expression for the steady-state fluorescence depolarization for prolate molecules with the emission transition moment parallel to the long axis, has been derived. The present theoretical results differ from those of previous studies and are in good agreement with the ex­perimental results.
EXAFS Study of Rutile and Anatase
Authors: Vlaic G. , Bart J. C. J. , Cavigiolo W. , Mobilio S. , Navarra G.
Published: February 2015

Two crystallographic forms of TiO2 (rutile and anatase) were subject to an extended x-ray absorption fine structure study at the K threshold of titanium. Data analysis was carried out by Fourier methods and curve fitting techniques. Using the theoretical phases, Ti-O bond distances of 1.93(1) Å were derived both for rutile and anatase, as compared to the crystallographic values of 1.948 - 1.980(1) Å (rutile) and 1.934-1.980(1) Å (anatase). The ratio of the cation coordination numbers Nr/Na = 1.07 is close to the theoretical value.