Influence of zirconium on the crystallization of ETS-10 molecular sieve

Summary The ETS-10 is a newly formed titano-silicate the structure of which was resolved thanks to the XRD, EDS, HREM and mass NMR. The ETS-10 is a potentially good catalyst. The aim of this research is to study the physicochemical properties of ET(Zr)S-10 obtained from a gel containing different amounts of Zr. The analyses used are XRD, thermal analysis (TG-DSC), SEM, and ²⁹Si NMR.     

Studies on the use of needle-free injection device on proteins

In the following communication we report the evaluation of 18 proteins that were processed by a specific needle free injection device. The processed protein samples were analyzed by two HPLC techniques, reversed-phase liquid chromatography (RPLC) and size-exclusion chromatography (SEC). These techniques are two of the most widely used analytical techniques in the biopharmaceutical industry for the characterization, integrity assessment and stability study of peptide and protein products. The results indicate that needle free injection, using the specific device of this study, is not damaging to the studied proteins and does not generate aggregates. We found no evidence of the predicted possible effects of needle free injections, and concluded that needle free delivery is in general not different than any other delivery system and that its use should be evaluated on a case by case basis. It has to be noted that there are various needle free device designs and our work was performed using an Iject from Bioject. Our conclusions therefore should be limited to the Iject design we used in this study. In the reported experiments we used commercially available (economical) model proteins, which facilitate the use of the results for future comparison and reference. The work reported here can serve as a reference to illustrate the benign nature of our needle free injection device. It also highlights an interesting analogy between a set of phobias that were seen to have plagued the early stages of biochemistry and HPLC, on the one hand, and some attitudes that appear to hinder the widespread acceptance of needle free injection at present time, on the other. These phobias were identified and named by Professor Csaba Horváth, the father of HPLC, as barophobia, siderophobia and lithophobia. Today a wealth of evidence is available to indicate that those phobias are ungrounded and that the negative observations can be explained in most cases by adsorption and prevented by proper formulations and solvent conditions.     

Silicon-containing amide,benzimidazole, hydrazide,and oxadiazole polymers

This study reports the synthesis of new silicon-containing amide, benzimidazole hydrazide, and oxadiazole polymers. Procedures are described for the preparation of several intermediate compounds. The silicon-containing polymers are soluble in organic solvents. Solution-cast films from the polymers generally are flexible and exhibit good adhesion to glass and metal surfaces. Preliminary examination indicates that the polymers are heat-stable at elevated temperatures.     

Oscillations in the expansion of solid 4He into vacuum

The particle flux through a micron-sized orifice into vacuum from a source chamber filled with solid 4He exhibits a striking sequence of periodic bursts. The period increases (decreases) with pressure (temperature), vanishing at the melting point for temperatures above the upper lambda point at 1.76 K. The oscillations are attributed to a periodic collapse of the solid induced by the accumulation of excess vacancies injected at the orifice and the period provides information on vacancy diffusivity. Dramatic deviations from this behavior below 1.76 K suggest important modifications in the flow properties of solid 4He induced by the excess vacancies.     

Distribution of aluminum in different periodical building units of MOR and BEA zeolites

Various commercial, homemade, and dealuminated mordenites (MOR) and beta (BEA) zeolites as well as cobalt modified BEAs have been characterized by 29Si- and 27Al solid-state magic angle spinning nuclear magnetic resonance (MAS-NMR) spectroscopy. The quantitative contributions of Si(nAl) and Si(OH)x sites to the NMR signal intensities were calculated from the various Si/Al ratios and relative 29Si and 27Al NMR signal intensities assuming a special distribution of aluminum in different periodical building units of the zeolite framework. A different dealumination and silanol formation mechanism for MOR and BEA was suggested. We conclude that we are able to distinguish the Si(OH)x groups that are original defect sites or produced in a dealumination or calcination process.     

Amplified Biochemical Oscillations in Cellular Systems

We describe a mechanism for pronounced biochemical oscillations, relevant to microscopic systems, such as the intracellular environment. This mechanism operates for reaction schemes which, when modeled using deterministic rate equations, fail to exhibit oscillations for any values of rate constants. The mechanism relies on amplification of the underlying stochasticity of reaction kinetics within a narrow window of frequencies. This amplification means that fluctuations have a dominant effect, even though the number of molecules in the system is relatively large. The mechanism is quantitatively studied within simple models of self-regulatory gene expression, and glycolytic oscillations.     

Effect of dissolution of Θ-phase on characteristic parameters of work-hardening in AL-2·5wt. % Cu alloy

Stress-strain curves of slowly cooled and quenched Al-2·5 wt. % Cu alloy were studied in the temperature range 693 K to 773 K. The linear work-hardening coefficient, the fracture time, the yield stress and the fracture stress of annealed and quenched samples decreased with increasing deformation temperature and exhibited a minimum at 733 K. The X-ray analysis of the slowly cooled and quenched samples showed that the lattice parametera of Al-matrix and the ratioc/a of the tetragonal -phase reached a minimum and a maximum value, respectively, at the dissolution temperature.     

On the Oximine Complexes of Transition Metals 106. Spectroscopic and DSC Study of Some Complexes of the Types [Cu(DioxH)2] and [CuX2·DioxH2]

Several new complexes of the types [Cu(DioxH)2] and [CuX2·DioxH2] (DioxH2: aliphatic or alicyclic α-dioxime) were obtained and characterized by means of near and far Fourier transformation IR spectroscopy. The thermal decompositions of seven complexes of these types were studied by using DSC measurement data. For several decomposition stages, apparent kinetic parameters were derived by means of the nomogram method. This revised version was published online in July 2006 with corrections to the Cover Date.     

KL,S → l+l− decays in the quark model of superconductivity type

The probabilities of K_L,S l⁺l^– decays are calculated by considering only the dominant two-lepton channel K_L,S ^{* *} l⁺l^–. The transitions K⁰ X, where X=⁰,, or (700) dominating in the K_L,S ^{* *}decay amplitudes, are described by the effective weak Lagrangian. The matrix elements of four-quark operators are calculated within the framework of the quark model of superconductivity type. It is shown that the leading contribution to matrix elements of K⁰ X transitions comes from the penguin operator matrix elements.