Estimation of trace elements in some medicinal plants used in anti‐cancer drugs by PIXE

A trace elemental analysis was carried out in various parts of 12 anticancer medicinal plants, using the PIXE (particle‐induced X‐ray emission) technique. A 3‐MeV proton beam was used to excite the samples, and spectra were recorded using a Si (Li) detector. Data analysis was done using the GUPIX software. The elements Cl, K, Ca, Ti, V, Mn, Fe, Ni, Cu, Zn, Br and Sr were identified, and their concentrations estimated. The results of the present study provide justification for the usage of these medicinal plants in the development of anticancer drugs. Copyright © 2012 John Wiley & Sons, Ltd.     

Prozessanalytik beim PUREX-Verfahren

PUREX process analytical chemistry is to generate information about the actual chemical state of the procedure. This originates mainly from current analytical investigations of appropriate solution samples. A lot of special arrangements, analytical equipment and methods and, last not least, experience is necessary. This paper reviews the problems in the field and describes a conception of process analytical chemistry with respect to an experimentally orientated situation.     

EXAFS study of zirconium alkoxides as precursors in the sol-gel process: II. The influence of the chemical modification

EXAFS studies of primary zirconium alkoxides Zr(OR)₄ with OR = n-propoxide and n-butoxide, dissolved in their corresponding alcohols and chemically modified with acetylacetone (Hacac) and acetic acid (HOAc) in different molal ratios, are presented. The EXAFS-spectroscopic results, supported by FT-IR-studies, indicate a different chemical behavior of the complexing agents. In contrast to acetylacetone, the addition of acetic acid does not change the oligomeric structure of the zirconium alkoxides. Amazingly, the modification with acetic acid leads, in comparison to the pure compounds, to a shortened metal centre distance, whereas in the reaction with acetylacetone the Zr-Zr distance is not changed. With the determined distances and a rough quantitative inclusion of the coordination numbers it was possible to deduce detailed structure models.     

High-efficiency 10 J diode pumped cryogenic gas cooled Yb:YAG multislab amplifier

We report on the first demonstration of a diode-pumped, gas cooled, cryogenic multislab Yb:YAG amplifier. The performance was characterized over a temperature range from 88 to 175 K. A maximum small-signal single-pass longitudinal gain of 11.0 was measured at 88 K. When amplifying nanosecond pulses, recorded output energies were 10.1 J at 1 Hz in a four-pass extraction geometry and 6.4 J at 10 Hz in a three-pass setup, corresponding to optical to optical conversion efficiencies of 21% and 16%, respectively. To our knowledge, this represents the highest pulse energy so far obtained from a cryo-cooled Yb-laser and the highest efficiency from a multijoule diode pumped solid-state laser system.     

EXAFS study of zirconium alkoxides as precursor in the sol-gel process: I. Structure investigation of the pure alkoxides

The properties of materials obtained by sol-gel processing show a certain dependence on the type of metal alkoxide and the solvent. Some authors assumed that these effects are caused by the degree of oligomerization of the metal alkoxides and their solvation. In order to obtain information on the structure and molecular complexity of the metal alkoxide we performed an EXAFS study on primary zirconium alkoxides Zr(OR)₄, with OR = n-propoxide and n-butoxide in solution of their parent alcohol. The EXAFS data for zirconium iso-propoxide have been used as a reference, because its solid state structure is known from X-ray analysis. The Zr-Zr correlations which were observed for all investigated systems provide evidence for an oligomeric structure. Because the analysis of the co-ordination spheres around the central Zr-atom revealed different Zr-O bond lengths, some of the formerly postulated structure models can be ruled out. We propose solvated dimers or trimers or mixtures of both species as possible structures of zirconium propoxide and zirconium butoxide in solution of their parent alcohol.