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AbstractIn the second version of the Common European Framework of Reference for Visual Competence (CEFR_VC) discussed in this journal issue, the main competency dimensions: creation and reception are represented in 16 sub-competencies, with an overarching competence dimension of metacognition. Visual Rubrics (VRs) support the assessment process of visual competency through an in-depth understanding of the content and levels of competences developed in an art education programme. Activities and their quality are captured in symbolic visualizations (images and explanatory textual rubrics) that scaffold the learning path and turn the competence development process into a metacognitive experience. Based on the first version of the Common European Framework of Visual Literacy (CEFR-VL), VRs for secondary-level art education were successfully employed in five European countries as summative assessment tools. In Hungary, the VR development continued with the new version of the framework, the Common European Framework of Visual Competency (CEFR-VC to explore the adaptability of VRs in a variety of educational settings. The tool proved to be useful in formal, school-based education as well as in the informal educational environment of museums. In this article, we explain the structure and imagery of the VRs and discuss their reception by art educators.

Purpose: Assessing the rupture probability of intracranial aneurysms (IAs) remains challenging. Therefore, hemodynamic simulations are increasingly applied toward supporting physicians during treatment planning. However, due to several assumptions, the clinical acceptance of these methods remains limited. Methods: To provide an overview of state-of-the-art blood flow simulation capabilities, the Multiple Aneurysms AnaTomy CHallenge 2018 (MATCH) was conducted. Seventeen research groups from all over the world performed segmentations and hemodynamic simulations to identify the ruptured aneurysm in a patient harboring five IAs. Although simulation setups revealed good similarity, clear differences exist with respect to the analysis of aneurysm shape and blood flow results. Most groups (12/71%) included morphological and hemodynamic parameters in their analysis, with aspect ratio and wall shear stress as the most popular candidates, respectively. Results: The majority of groups (7/41%) selected the largest aneurysm as being the ruptured one. Four (24%) of the participating groups were able to correctly select the ruptured aneurysm, while three groups (18%) ranked the ruptured aneurysm as the second most probable. Successful selections were based on the integration of clinically relevant information such as the aneurysm site, as well as advanced rupture probability models considering multiple parameters. Additionally, flow characteristics such as the quantification of inflow jets and the identification of multiple vortices led to correct predictions. Conclusions: MATCH compares state-of-the-art image-based blood flow simulation approaches to assess the rupture risk of IAs. Furthermore, this challenge highlights the importance of multivariate analyses by combining clinically relevant metadata with advanced morphological and hemodynamic quantification.

The parabolized stability equations (PSE) are a widely used, efficient method to calculate the evolution of streamwise traveling instabilities in spatially developing, weakly nonparallel flows. Although the PSE are very economical, computational time can be significant due to the repeated solution of linear systems of equations in each marching step. The linear systems of equations are typically solved by LU factorization because of the moderate size and the sparsity of the matrices. In this paper, instead of repeated calculation of the LU factorization, a single LU factorization is calculated in each marching step and used as a preconditioner for an iterative solver. Numerical experiments are conducted on the plane-marching (3D) incompressible PSE, nonlinear PSE (NLPSE) with explicit discretization of the nonlinear terms, and NLPSE with implicit treatment of the nonlinearities. It is shown that the time spent on the solution of the linear systems of equations was reduced by a factor of 2.5, 4.5–7.5, and 20–60 for the three cases, respectively. The only requirement of the proposed numerical techniques is that the solution varies slowly in the marching direction; therefore it is expected to be applicable to similar boundary layer stability problems or slowly varying parabolic partial differential equations. This is supported by the fact that the numerical method was applied to the Boundary Region Equations (BRE) and the line-marching (2D) PSE, the latter being a much smaller problem than its plane-marching counterpart. In these cases, a factor of 50% and 15–30% decrease in the net time of the linear equation solution is reported, respectively. • A simple method is outlined to accelerate the solution of plane marching PSE. • The solution of both the linear and the nonlinear plane marching PSE can be accelerated. • The efficient solution method renders the implicit discretization of the nonlinear terms feasible. • The applicability of the method to slowly varying equations is demonstrated on the BRE. [ABSTRACT FROM AUTHOR]

In this paper, CFD-based results are presented on the estimation of losses in bends with validated numerical models for single-phase, incompressible Bingham fluids. Five fittings were investigated: 90∘bends of different R/Dratios between 1 and 10. Bingham plastic fluids were studied with Hedström numbers in the wide range from 1 to 109. Loss coefficients are given as the function of the generalized Reynolds number (Regen=0.1–17 800) and the generalized Dean number (Degen=0.1–12 600). The paper presents friction factors as well that were consistent with the literature. It was shown that at low generalized Dean numbers of Degen<40, the losses of the bends were caused purely by the wall friction and can be estimated from the Degen. In a broad range of higher Regenand Degennumbers, the loss coefficients were separated at the basis of the Hedström numbers. This phenomenon was mainly observable in the case of high curvature and was attributed to the flow patterns. Our study investigated this range with the bend of R/D=1in detail: flow patterns in the bend and at the upstream side of the fitting were examined. An approximating equation and the fitting parameters were also given for loss coefficients.

Aims. Absolute recombination rate coefficients for two astrophysically relevant Na-like ions are presented.

A retrospective modeling was performed in a case with restenosis after 6 months of a DES implantation to investigate the effect of the step-down at the distal edge of the stent on the wall shear stress (WSS) using 3D coronary angiography reconstruction and the intracoronary pressure traces during a cardiac cycle. The kinetics of the WSS was calculated through the cardiac cycle along the reconstructed vessel by fluid dynamic analysis. Contrary to the previous reports the greatest amplitude and average of the arterial WSS was detected where the restenosis developed later at the site of the step-down.

One of the main reason for the incorrect development of embryos derived from somatic cell nuclear transfer is caused by insufficient demethylation of injected somatic chromatin to a state comparable with an early embryonic nucleus. It is already known that the epigenetic enzymes transcription in oocytes and early embryos of several species including bovine and porcine zygotes is species-dependent process and the incomplete DNA methylation correlates with the nuclear transfer failure rate in mammals. In this study the transcription of DNA methyltransferase 1 and 3a (DNMT1, DNMT3a) genes in early embryonic stages of interspecies (bovine, porcine) nuclear transfer embryos (iSCNT) by RT-PCR were analyzed. Coming out from the diverse timing of embryonic genome activation (EGA) in porcine and bovine preimplantation embryos, the intense effect of ooplasm on transferred somatic cell nucleus was expected. In spite of the detection of ooplasmic DNA methyltransferases, the somatic genes for DNMT1 and DNMT3a enzymes were not expressed and the development of intergeneric embryos stopped at the 4-cell stage. Our results indicate that the epigenetic reprogramming during early mammalian development is strongly influenced by the ooplasmic environment.

The nonlinear dynamics of an acoustically excited spherical gas bubble in water is being investigated numerically. The applied model to describe the motion of the bubble radius is the Keller–Miksis equation, a second order ordinary differential equation, which takes into account the compressibility of the liquid. During the radial oscillations of the bubble, it may enlarge and collapse violently causing high temperature and pressure or even launch a strong pressure wave at the collapse site. These extreme conditions are exploited by many applications, for instance, in sonochemistry to generate oxidising free radicals. The recorded properties, such as the very high bubble wall velocity, and maximum bubble radius of the periodic and chaotic solutions are good indicators for the strength of the collapse. The main aim is to determine the domains of the collapse-like behaviour in the excitation pressure amplitude–frequency parameter space. Results show that at lower driving frequencies the collapse is stronger than at higher frequencies, which is in good agreement with many experimental observations (Kanthale et al., 2007, Tatake and Pandit, 2002). To find all the co-existing stable solutions, at each parameter pair the model was solved numerically with a simple initial value problem solver (4th order Runge–Kutta scheme with 5th order embedded error estimation) by applying 5 randomly chosen initial conditions. These co-existing attractors have different behaviour in the sense of the collapse strength. [ABSTRACT FROM AUTHOR]

The first synthesis of both enantiomers of 6,7dimethoxy1,2,3,4tetrahydroisoquinoline1carboxylic acid was accomplished through dynamic kinetic resolution in procedures based on CALB or subtilisin Carlsbergcatalysed enantioselective hydrolysis of the corresponding ethyl esters in aqueous NH4OAc buffer at pH 8.5. The products were obtained with high enantiopurity 92–93  ee in good yields 85–92 . R1,2,3,4Tetrahydroisoquinoline1carboxylic acid was obtained with high enantiopurity 98  ee and in good yield 85  in a CALBcatalysed process, under similar conditions.© WileyVCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008

Abstract: Temporally resolved schlieren flow visualization and Laser-Doppler Anemometry (LDA) measurements have been performed on real flue organ pipes during the stationary state as well as during the attack transient. The techniques prove highly efficient in providing information on the details of the flow. The measurements reveal several details of the flow and demonstrate its importance in the sound formation. The spatial development of harmonics as well as the influence of nicks is also studied. It turns out that the jet instability wave behaves differently when the jet moves inward and outward of the pipe.

A simple and efficient direct enzymatic method was developed for the synthesis of 4-aryl-substituted β-lactams and the corresponding β-amino acid enantiomers through the CAL-B (lipase B from Candida antarctica)-catalyzed enantioselective (E>200) ring cleavage of the corresponding racemic β-lactams with 1 4;equiv. of H2O in i-Pr2O at 60 °C. The product (R)-β-amino acids (ee≥98%, yields≥42%) and unreacted (S)-β-lactams (ee≥95%, yields≥41%) could be easily separated. The ring opening of enantiomeric β-lactams with 18% HCl afforded the corresponding enantiopure β-amino acid hydrochlorides (ee≥99%).

This part is a collection of short book reviews from the following authors: Biagio D'Angelo: Milongas y otros ritmos, Maria Luiza  Guarnieri Atik: Vicente do Rego Monteiro-um brasileiro da França, Luciano Morbiato (ed.): Scartafaccio d'agricoltura. Manoscritto di un contadino di Spiné di Oderzo (1805-1810), Paul Richard Blum: Philosophieren in der Renaissance, Edit Bors: Az idő poétikája az önéletírásban. Rousseau, Gide, Sartre önéletírásának szövegnyelvészeti-pragmatikai elemzése.

The article attempts to present everyday religiousness and the effects of religion on culture, and illustrates them with a case study. Following Geertz (1994), the author emphasizes the qualitative aspect of religion. Based on some of the results of her field work carried out in Padova, the author shows that it is the individual and everyday religiousness that can lead us to gain a better understanding of the cultural dimensions of human behaviour. She goes on to illustrate the extent religion has rooted in traditional rural life, as well as providing examples and a brief analysis of everyday religious customs and the effect religion exerts on culture.

The interaction of hydrogen, ethylene and their mixtures with a commercial Pd black was studied. Hydrogen treatment at 300 K created a rather clean Pd surface with some residual carbon. Ethylene introduced in high hydrogen excess exerted hardly any influence on the metallic properties of Pd, as shown by X-ray and ultraviolet photoelectron spectroscopy (XPS and UPS). The carbon content did not change. Contacting Pd with ethylene in low excess of H₂ or without any hydrogen changed the Pd 3d line, indicating its chemical interaction with C. Simultaneously, a new component appeared in the C 1s region at BE∽283.5 eV. It indicated the formation of Pd–C bonds, responsible for changes in the Pd valence state. Intensity drop at the near-Fermi edge region in UPS corroborated this interaction. Pd also underwent considerable structural rearrangement, as shown by the appearance of a large peak in the UP spectra at ∽8 eV, corresponding to the enrichment of the sodium carbonate impurity on the surface. This component proved to be a good indicator of surface flexibility.

Pt black has been studied by X-ray and ultraviolet photoelectron spectroscopies (XPS, UPS) and XRD after reduction, after presintering and after subjection to various in situ treatments. All samples contained carbon and oxygen impurities. Sintering decreased the abundance of C. Samples introduced from the air contained a large amount of oxygen whose amount dropped markedly upon keeping the Pt in UHV for several hours. XPS and UPS revealed considerable amounts of nondissociatively chemisorbed CO after this treatment. An in situ hydrogen treatment at 603 K decreased the O content further but increased the concentration of surface carbon. The Pt 4f regions showed some oxidized Pt both before and after sintering. Pt reached an almost clean metallic state after UHV treatment. This state seemed to remain unchanged after further manipulations. Hardly any electronic interaction could thus be observed between Pt and its main impurity: C, which was present mostly as graphite and C_xH_y polymer after treatment with n-hexane plus hydrogen. n-Hexane alone produced mostly “disordered’' surface carbon species. The intensity of higher-order X-ray reflections of Pt was suppressed upon sintering. This anisotropy was reversed after in situ H₂ treatments, inducing recrystallization with preferential formation of higher Miller-index planes, (220) and (311). These reflections were again suppressed after exposure to n-hexane. Thus, adsorbate-induced solid-state rearrangement occurred as a result of the interplay of surface and subsurface impurities. The catalytic reactions of n-hexane over Pt black subjected to different pretreatments were different: abundant (220) and (311) reflections promoting isomerisation, C₅-cyclisation and also hydrogenolysis. Carbon accumulation decreased the “intrinsic’' activity of the Pt fraction detected by XPS. Selectivities, in turn, were governed by the crystallite structure as well as by the presence of composite platinum–carbon sites. “Disordered’' surface carbon species poisoned all skeletal reactions and favoured dehydrogenation to hexenes.

Metal/cerium-oxide systems were practically not studied in hydrocarbon reactions. Chemisorption properties—in temperature programmed reduction, hydrogen adsorption, and H2/O2titration—and catalytic behavior of ceria-supported Pt and Rh catalysts with different metal loadings and with two pre-reduction temperatures (LTR, TR=573 K and HTR, TR=773 K) were investigated. Pt/CeO2was tested in transformation of n-hexane while Rh/CeO2in ring opening of methylcyclopentane (MCP). Higher spillover activity was found for the LTR Rh samples than for HTR ones. The opposite was true for Pt. The Rh/ceria samples showed ordinary catalytic behavior: structure insensitivity was observed for the first CC bond cleavage of MCP on Rh/ceria and the further reaction of the ring opening intermediates was affected by the surface hydrogen concentration. The Pt/LTR samples showed catalytic properties similar to EUROPT-1, while the HTR samples were different, namely the higher spillover activity caused high C5-cyclization selectivity on the catalyst with low metal loading, and surprisingly high hydrogenolysis selectivity on that with higher metal loading.

The bulk composition, structure and valence state of an alumina supported PdMoO_x catalyst have been studied by X-ray diffraction (XRD), high resolution transmission electron microscopy (HRTEM), energy dispersive X-ray (EDX) analysis, X-ray photoelectron spectroscopy (XPS) and ion scattering spectroscopy (ISS) before and after sulfiding. Results are compared with data from a previous study of PtMoO_x. Temperature programmed reduction (TPR) data indicate that both catalysts contain Pd and Pt in metallic form with high metal dispersion. Pd₄S and Pd₁₆S₇ are formed upon sulfidation of PdMoO_x opposite to PtS formation in PtMoO_x. The sulfur uptake by alumina supported MoO_x, PdMoO_x and PtMoO_x was determined by using H₂³⁵S tracer and compared with XPS data on the sulfur content of the sulfided catalysts. EM data indicate, that MoS₂ forms patches on the support surface. The mean sulfur to metal ratio in the catalysts, as calculated from sulfur uptakes, measured by radiotracer experiments, is equal with that measured by XPS for the topmost layers in the case of MoO_x, substantially lower in the case of PdMoO_x and somewhat lower in the case of PtMoO_x. The extent of sulfur heteroexchange and the ratio of mobile sulfur is much higher in the case of molybdena alone than in the case of metal doped catalysts.

Pt black samples were exposed to 2,4-hexadiene (24HD) at 603 and 693 K, alone or in the presence of excess hydrogen. The 24HD underwent C=C double-bond shift, geometric isomerization, and minor aromatization during its contact with Pt in the absence of H2. It was hydrogenated to hexenes and hexane when hydrogen was present. Test runs with an n-hexane–hydrogen mixture after 24HD treatment showed a more pronounced decrease of activity and a loss of isomerization/cyclization selectivities after exposure without hydrogen. The amount, structure, and possible chemical state of residual carbon were examined by transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). The sintered metal contained some inherent (likely harmless) carbon impurity, the amount of which increased upon exposure to 24HD to 44–50%, higher temperatures and lower H2concentration resulting in more solid carbon. Regeneration by an O2–H2treatment removed much, but not all, of the solid carbon deposit. Difference spectra of hexadiene-treated and regenerated samples showed an excess of graphite in the carbonized samples whereas Pt/C was more abundant after regeneration, in agreement with C 1 s line fitting. Transmission electron microscopic examinations showed mainly pyrolytic carbon. Graphitic layers (not highly ordered ones) perpendicularto the Pt surface were identified after exposure to 24HD/H2mixtures of various composition. Graphitic and amorphous C caused a nonselective deactivation. Difference C 1 s spectra showed a component with a binding energy at ∼284.1 between graphite and Pt/C. The suppression of the catalytic propensities in skeletal reactions (isomerization and C5cyclization) and the difficulty of self-reactivation in the prolonged test runs were consistent with the presence of this type of deposit representing, likely, a disordered nongraphitic hydrocarbon oligomer.

Tenascin is generally classified as an anti-adhesive protein. Many cells do not adhere to tenascin or if they adhere they do not spread. In this study we analysed the stromal expression of tenascin-C in primary, second primary and recurrent breast carcinomas and the ability of tenascin-C to stimulate the focal adhesion plaques in MDA-MB-435 breast carcinoma cell line. To assess the tenascin-C expression formalin-fixed, paraffin-embedded specimens of 20 specially selected breast carcinomas and their recurrences (14) or a second primary breast cancer of the same patient (6) were examined with immunohistochemical methods. We also studied the effect of tenascin-C on focal adhesion plaques added to MDA-MB-435 breast carcinoma cell line. During a median 2,9-year patient follow up 14 local recurrences and 6-second primary breast carcinomas developed in the 20 patients. In 3 cases a second recurrence occurred. The presence of tenascin in tumor cells, in the proliferating and some normal ducts, near to the tumor cell nests, in the stroma and in ductal carcinoma in situ component of the invasive carcinoma may suggest the role of tenascin played in tumor cell migration. Soluble tenascin added to the cell culture had minimal or no effect on focal adhesion plaques. Tenascin only seems not to be of prognostic value in predicting the local recurrence of breast cancer.

The surface composition of Rh and Pt blacks (as determined by XPS) shows carbon and oxygen impurities in the untreated state. Oxygen on Pt is present as adsorbed O as well as OH/H2O groups and oxidized carbon. Rh was partly oxidized to Rh2O3, in agreement with UPS showing hardly any Fermi‐edge intensity in untreated Rh as opposed to untreated Pt. High Fermi‐edge intensities indicated a predominant metallic surface after an in situ treatment with H2at 483 K, increasing the purity (XPS) to ∼90%. This treatment reduced Rh to metal and removed its C impurity. Pt, in turn, retained much carbon after H2treatment, present mainly as graphitic carbon. A minor amount of CO was also detected, some of the O 1s peak belonging to it. The two metals were tested in methylcyclopentane reactions. Considering the necessity of carbon for nondegradative reactions and oxygen enhancing fragmentation, a correlation is suggested between the typical impurities of Pt and Rh and their respective catalytic propensities: the high fragmentation activity of Rh and the predominant nondegradative reactions to C6“ring opening products” on Pt.

Pt black was exposed to n>-hexane/H2mixtures between 483 and 663 K followed by O2and H2treatments at 603 K. XP and UP spectra were measured without exposing the samples to air. 20–30% carbon accumulated after hydrocarbon exposures. O2removed most carbon. The surface C content increased after a subsequent contact with H2, C 1s showing more “atomic carbon” as opposed to graphite after n-hexane exposure. Anisotropic recrystallization of Pt black favoring (220) and (311) lattice planes occurred under hydrogen-rich conditions. Both findings were attributed to a H2-induced solid-state rearrangement; H atoms penetrating into the crystal lattice, force subsurface carbon and oxygen atoms to the surface and a concomitant restructuring would occur. Thus another “hydrogen effect” has been recognized, leading to structures favorable for skeletal reactions of alkanes.

We have synthesized and characterized new chimeric peptides by inserting an epitope of the glycoprotein D (gD) of herpes simplex virus (HSV) serotype 1 as 'guest' sequence in the 'host' structure of α-conotoxin GI, a 13-residue peptide (ECCNPACGRHYSC) isolated from the venom of Conus geographus. The 276-284 region of HSV gD-1 selected for these studies is highly hydrophilic and adopts a β-turn. The α-conotoxin GI also contains a β-turn in the 8-12 region, stabilized by two disulfide bridges at positions 2-7 and 3-13. Thus, the tetramer sequence of α-conotoxin, ⁸Arg-His-Tyr-Ser¹² has been replaced by Asp-Pro-Val-Gly (DPVG), identified previously as the epitope core. The syntheses were performed by Fmoc strategy on Rink resin and DTNB or air oxidation were applied for the formation of the first 3-13 disulfide bond in the presence of guanidinium hydrochloride. For the formation of the second disulfide Cys²-Cys⁷ three different oxidation procedures [iodine in 95% acetic acid, air oxidation in dimethyl sulfoxide/1 m HCl or Tl(tfa)₃ in trifluoroacetic acid (TFE)] were compared. The high-performance liquid chromatography purified peptides were characterized by electrospray mass spectrometry and amino acid analysis. The bicyclic HSV-α-[Tyr¹]-conotoxin chimeric peptide and native α-conotoxin GI showed similar circular dichroism spectra in phosphate-buffered saline (PBS) and in a PBS-TFE 1 : 1 (v/v) mixture, which might suggest that these compounds also share similar secondary structures. In immunologic studies the characteristics of the primary and of the memory immunoglobulin (Ig) M- and IgG-type antibody responses showed that the bicyclic HSV-α-[Tyr¹]-conotoxin chimera is capable to induce strong antibody responses in C57/Bl/6 mice but was poorly immunogenic in CBA and BALB/c mice. Data obtained with the C57/Bl/6 serum indicate that the polyclonal antibodies recognize the DPVG motif presented in the bicyclic HSV-α-[Tyr¹]-conotoxin and some reactivity was also found with the monocyclic but not with the linear form of the chimera. Results with two IgM type monoclonal antibodies from a bicyclic HSV-α-[Tyr¹]-conotoxin immunized C57/Bl/6 mouse also point to the specific interaction with the DPVG sequence. Taken together these studies suggest, that the relative intensity of DPVG-specific responses was found to be dependent on the mouse strain and on the conformation of the chimeric molecules. We found that the IgM monoclonal antibodies are able to recognize the linear DPVG sequence, while the majority of IgG antibodies is directed to the same motif in a conformation stabilized by double cyclization.

n‐hexane was reacted on two Pt–Sn/Al2O3catalysts, one prepared by coimpregnation (T) the other by using a bimetallic PtSn complex precursor (N). Both catalysts produced isomers, methylcyclopentane fragments and benzene, the aromatic selectivity being higher on catalyst N. The hydrocarbon entities remaining after reaction were removed by hydrogen treatment. They contained methane, C2–C5fragments (not observed on Pt, thus unique for PtSn) and benzene. The possible state and composition of chemisorbed carbonaceous entities during reactions are discussed. More hydrocarbons, including slightly more methane could be hydrogenated off from catalyst Nof lower dispersion. The higher overall activity of catalyst Nin the presence of more than one C per surface Pt points to its higher coke tolerance.

Hexane was tested under similar conditions on Al2O3 supported Pt, Ir and Pt–Ir catalysts. A conventional impregnation on commercial alumina and a sol–gel procedure involving the introduction of the Pt or Ir components at the commencement of gelification were applied for the preparation of monometallic catalysts. Pt–Ir samples were prepared by co-impregnation or using a bimetallic complex precursor, [Ir(NH3)5Cl][PtCl4], produced in the pores of the support. Increasing H2 pressure at both 603 and 663 K enhanced the overall activity and the very pronounced hydrogenolysis on Ir. Non-degradative products, including isomers, methylcyclopentane, benzene and hexenes, showed, as a rule, maximum rates as a function of p(H2) on Ir also, in agreement with earlier and present reports concerning Pt. Both Pt and Ir catalysts on a sol–gel alumina were superior in non-degradative reactions to their conventional counterparts. The hydrogenolysis activity of both bimetallic catalysts was below the average for Pt and Ir, indicating Pt–Ir interactions. These were more pronounced with Pt–Ir prepared from a complex precursor, showing a higher activity in non-degradative reactions, more manifest at 663 K.

Skeletal reactions of n-hexane on 6.3% Pt/SiO2(EUROPT-1) have been studied as a function of hydrogen pressure between 483 and 633 K. Turnover frequencies were calculated for the overall reaction as well as for individual processes, i.e., hydrogenolysis, isomerization, C5-cyclization, and aromatization as well as dehydrogenation to hexenes. Curves with a maximum were observed for the conversion as a function of hydrogen pressure. Arrhenius plots could be calculated for constant hydrogen pressures as well as for maximum rates. The former lines “bend down” at higher temperatures. This may explain the different values determined in different experimental setups. Different straight Arrhenius lines were determined in the negative and in the positive hydrogen order range. We regard activation energies calculated at constant hydrogen pressures as “apparent” while those computed at the maximum rates may approximate “true” values. The apparent activation energies show compensation effect and give different compensation lines in the range of positive and negative hydrogen orders. In the case of bent Arrhenius plots, the computation resulted in virtual isokinetic parameters. Arrhenius parameters and compensation phenomena were determined for individual reactions, too. These results are in a good agreement with the mechanism suggested earlier for each reaction.

ABSTRACT: This study examines the relationship between membrane lipid microviscosity and susceptibility of villous trophoblast to lysis by natural cytotoxic cells.

This work is the continuation of the search for such a cosmological model using which the observed redshift distribution of galaxies in the sample of Broadhurstet al. (1990) turns out to be maximally periodic in the calculated spatial distance. In a previous work, Paálet al. (1992) have demonstrated that among theflat models with non-negative cosmological constant (e.e., vacuum density) the one with a vacuum: dust ratio 2:1 provides the optimum. Now we extend that study to the case of arbitrary space curvature and find equally good periodicity in a surprisingly wide range of models. By use of the dimensionless parameters ?0=?0/?crit and?0=?/3H02 acceptable periodicity is obtained forall points of the parameter plane within the strip between the parallel lines 0.83?0-0.300(?0)<0.83?0+0.85(?0<1.8), whilst the best periodicities appear along the line?0=0.83?0+0.39 fitting to the previous optimum at ?0=1/3,?0=2/3. Any nonpositive value of?0 gives bad periodicity unless the space curvature is strongly negative and ?0<0.4. Fairly good periodicity is observed only in the range of the deceleration parameter -1.2=q0<0.2, corresponding to a small or even negative total gravitational attraction and an expansion time-scale longer than usually expected.

The uptake of H2S has been determined for Al2O3 supported Mo, RuMo and PdMo catalysts, exposed previously to cyclohexanol, cyclohexene or thiophene. The amounts of H2S-uptake were compared with those taken up by catalysts treated with H2S only. Significant differences were found in behavior of the different and differently treated catalysts with respect to their sulfur uptake.

Ring opening of ethylcyclopentane (ECP) was studied over 6.3% Pt/SiO2 (EUROPT-1) and 10% Pt/Al2O3, as a function of the hydrogen pressure. Both catalysts gave almost nonselective ring opening. Pt/Al2O3 produced also olefins, more side dealkylation and less fragmentation products. It is likely, that adlineation sites are operative over both catalysts.

Secondary Ion Mass Spectra of Pt-black exposed to ethylene at 633 K contain a PtC2H3 cluster identified tentatively with adsorbed ethylidyne like that reported for single crystal surfaces. The catalytic properties of Pt pretreated by ethylene are, to some respect, superior in hydrocarbon transformations to those containing other, less defined carbonaceous overlayers.

The amount and valence state of sulfur in sulfided Pt catalysts was monitored, together with parallel studies of the catalytic properties of these catalysts in order to clarify the catalytic effect of S in different chemical states on reactions of low-temperature n-hexane reforming. Pt black and 6% Pt/SiO2(EUROPT-1) were sulfided by H2/H2S. X-ray photoelectron spectroscopy (XPS) detected both sulfate and sulfide. The chemical state of Pt corresponded to metallic Pt with low amounts of S containing surface adlayer and/or PtS present. This could be observed with Pt black and also with EUROPT. With S present, both catalysts lost ca 95% of their activity in n-hexane transformation at 603 K, n-hexenes being the predominant products. Prolonged runs with n-hexane as well as regenerations using O2and H2removed most sulfidic S from Pt black and about half of the original activity came back. Isomers and methylcyclopentane were produced in this state with high selectivities. Some reactivation of EUROPT (where no sulfate could be detected) occurred within one single run. A uniform scheme is proposed to describe the effects of sulfate and sulfide. Accordingly, sulfate acts as a structural modifier occupying a fraction of the active surface. Sulfide in small amounts, in turn, has a bonding modifier effect and poisons selectively benzene and fragmentation, enhancing (within the reduced activity) the selectivity of C5-cyclization and, possibly, also that of isomerization.

In this investigation the daily amount of global radiation in cloudless days was determined using transmission factors which are function of the day of the year and the visibility. These parameters were obtained from measurements in a 20 years period in Budapest by numerical integration. The average difference between the calculated and measured daily sums was 6.9%. This fact indicates, that we have sufficiently correct method for calculation of clear-sky irradiance.

A new bimetallic Pt-Sn compound [Pt(NH3)4][SnCl6] has been used as precursor for the preparation of supported Pt-Sn/Al2O3 catalysts. A comparison of a dried sample with that prepared by coimpregnation displays different behaviour in TPR, chemisorption. The initial catalytic activity properties were checked in the reactions of cyclohexane dehydrogenation and cyclopentane ring opening, whilen-hexane skeletal reactions were used to probe the quasisteady-state activity. The catalyst prepared via the Pt-Sn complex precursors exhibited some-what lower specific activity. This fact, together with enhanced olefin formation fromn-hexane was taken as an indication of lower amount of contiguous Pt atoms and some electronic interaction between Pt and Sn in that catalyst.

A flow cell was constructed to measure infrared spectra of catalyst samples with controlled heating at 673 K. We monitored sulfidation of an unsupported Co-Mo catalyst by thiophene. Correlation was found between the intensity changes and frequency shifts of the metal-oxygen IR bands and the appearance of oxythiomolybdate bands and the simultaneous increase of thiophene conversion. These results point to short-living cobalt-oxythiomolybdates which may have highest HDS activity.

This chapter emphasizes on the metal-catalyzed cyclization reactions, with reference to oxide and dual-function catalysts. Product cycles may contain five or six carbon atoms. A common feature of any cyclization reaction is that a new intramolecular C-C bond is produced that would not have been formed in the absence of the catalyst. Those reactions in which one ring closure step is sufficient to explain the formation of a given cyclic product will be called “simple” cyclization processes, although their mechanism is, as a rule, complex. As few as six different kinds of adsorption are proposed in the chapter as being responsible for a great variety of hydrocarbon transformations over metal catalysts. This approach is fully accepted that the character of primary adsorption determines the structure of the product. One of the main points that is stressed is that very different reactions may often be concealed behind the expression “cyclization.” An attempt is made in the chapter to correlate primary adsorption (consequently the reactions expected) with two main factors: the nature of the metal and the amount of hydrogen available during the catalytic process. The latter may be of paramount importance: the amount of surface hydrogen may govern which type of chemisorbed species is formed and, by doing so, determine catalytic selectivity.

It is argued that the primordial density fluctuations needed for galaxy formation may have been of thermal origin in a quasi-exponential state of inflation.

The distribution of galaxies in the pencil-beam surveys of Broadhurstet al. which proved periodical across 8–10 consecutive steps in a flat dust model withq0=0.5 is found to reveal extended periodicity up to 16–17 phase-coherent steps, covering the total sample, in a flat, moderately inflationary model withq0=-0.5 (vacuum/dust ratio 2/1). In the latter model the vacuum component helps to reach the critical density and lengthens the expansion time-scale. It is shown that the explanation of the found periodicity as a consequence of space compactification as suggested by G. Paál twenty years ago in connection with apparent quasar periodicities is still possible.

The fact that the energy-momentum tensor has nonzero vacuum expectation value in some space-times (the so-called back reaction) indicates a nontrivial thermodynamics of such vacua. A consequent thermodynamic analysis of the problem in Robertson-Walker space-times shows that, in the generic case, the number of the independent extensives is 2, in spite of the fact that the energy density is completely determined by the time-evolution of the geometry since the preparation of the vacuum state. The appearance of a second independent extensive seems to be in direct connection with the extra entropy term in theGeneralized Second Law of Bekenstein and Hawking.

It has been shown by radiotracer studies that in the presence of copper and nickel cyclohexanol gives phenol exclusively via cyclohexanone, whereas in the presence of platinum there is a direct pathway for the dehydrogenation of cyclohexanol into phenol. Как было показано с помощью техники радиоактивных изотопов, циклогексанол в присутствии меди и никеля дает фенол, образующийся исключительно через циклогексанон, в то время как на платине циклогексанол непоседственно дегидрогенизируется в фенол.

For studying the homogeneous catalysis in oxidation our approach starts with the determination of the reaction sequence network of the non-catalytic oxidation using the KIM. The next step is the study of the effect of the catalyst complex and the transformation of the catalyst in the subsystems. The rate parameters collected (referring to the reactions of the catalyst complex with stable and short lived intermediates) can be used to simulate the subsystems and the overall catalytic system.