Nuclear electric dipole shielding in molecular ions

A formula, which includes the effects of finite nuclear masses, is derived for the force on a nucleus in a (possibly molecular) ion in a spatially uniform (possibly time dependent) electric field.     

Photodynamic Treatment of Red Blood Cell Concentrates For Virus Inactivation Enhances Red Blood Cell Aggregation: Protection with Antioxidants

Abstract— Photodynamic treatment (PDT) using phthalocyanines and red light appears to be a promising procedure for decontamination of red blood cell (RBC) concentrates for transfusion. A possible complication of this treatment may be induced aggregation of RBC. The production of RBC aggregates was measured with a novel computerized cell flow properties analyzer (CFA). The PDT of RBC concentrates with sulfonated aluminum phthalocy-anine (AIPcS4) and the silicon phthalocyanine Pc 4 under virucidal conditions markedly enhanced RBC aggregation and higher shear stress was required to disperse these aggregates. The clusters of cells were huge and abnormally shaped, unlike the rouleaux formed by untreated RBC. This aggregation was prevented when a mixture of antioxidants was included during PDT. Addition of the antioxidants after PDT reduced aggregation only partially. It is concluded that inclusion of antioxidants during PDT of RBC concentrates prior to transfusion may reduce or eliminate the hemodynamic risk that the virucidal treatment may present to the recipient.     

Conversion of amino hydroxyacids to oxazolidine-4-carboxylic acids,oxazolidine-5-carboxylic acids and tetrahydrooxazine-4-carboxylic acids

The title compounds are stable in aqueous solution above pH 7, and can be isolated following N-acylation.     

Xanthan gum production from cassava bagasse hydrolysate with Xanthomonas campestris using alternative sources of nitrogen

Cassava bagasse was hydrolyzed using HCl and the hydrolysate was used for the production of xanthan gum using a bacterial culture of Xanthomonas campestris. Cassava bagasse hydrolysate with an initial concentration of approx 20 g of glucose/L proved to be the best substrate concentration for xanthan gum production. Among the organic and inorganic nitrogen sources tested to supplement the medium—urea, yeast extract, peptone, potassium nitrate, and ammonium sulfate—potassium nitrate was most suitable. Ammonium sulfate was the least effective for xanthan gum production, and it affected sugar utilization by the bacterial culture. In media with an initial sugar concentration of 48.6 and 40.4 g/L, at the end of fermentation about 30 g/L of sugars was unused. Maximum xanthan gum (about 14 g/L) was produced when fermentation was carried out with a medium containing 19.8 g/L of initial reducing sugars supplemented with potassium nitrate and fermented for 72 h, and it remained almost the same until the end of fermentation (i.e., 96 h).     

Evaluation of an automated clean-up system for the isotope-dilution high-resolution mass spectrometric analysis of PCB, PCDD, and PCDF in food

An automated clean-up system was evaluated for the simultaneous analysis of polychiorinated dibenzo-p-dioxins (PCDD), dibenzofurans (PCDF), and biphenyls (PCB) in different foods. In addition to the seventeen 2,3,7,8-substituted PCDDIPCDF and four non-ortho PCB, by use of the clean-up system studied, it was possible to collect the eight mono-ortho and two di-ortho PCB and the seven indicator PCB in two separate fractions during the same clean-up run. The study was first performed using standard mixtures containing PCDD, PCDF and PCB, and a certified reference material. The recoveries of the 13C-labeled compounds ranged from 51 to 90%, indicating that the PCDD, PCDF, and PCB clean-up worked satisfactorily. Next, the automated system for PCDD, PCDF, and PCB analysis was evaluated for foods such as milk, egg, meat (beef, chicken, and pork), mussel, and olive oil. The recoveries of the 13C-labeled compounds ranged from 40 to 120% for PCB and from 57 to 113% for PCDD/ PCDF, meeting the requirements of well accepted methods. Thus, the automated clean-up system studied is a suitable alternative to conventional clean-up methods.     

Les groupes qui coincident avec leurs groupes adjoints

Sans résumé     

Comments on an ancient Greek racecourse: finding minimum width annuluses

For a set of measured points, we describe a linear-programming model that enables us to find concentric circumscribed and inscribed circles whose annulus encompasses all the points and whose width tends to be minimum in a Chebychev minmax sense. We illustrate the process using the data of Rorres and Romano (SIAM Rev. 39: 745–754, 1997) that is taken from an ancient Greek stadium in Corinth. The stadium’s racecourse had an unusual circular arc starting line, and measurements along this arc form the basic data sets of Rorres and Romano (SIAM Rev. 39: 745–754, 1997). Here we are interested in finding the center and radius of the circle that defined the starting line arc. We contrast our results with those found in Rorres and Romano (SIAM Rev. 39: 745–754, 1997).     

Extended network thiocyanate- and tetracyanoethanide-based first-row transition metal complexes

Linear chain thiocyanate complexes of M(NCS)(2)(OCMe(2))(2) (M = Fe, Mn, Cr) composition have been prepared and structurally, chemically, and magnetically characterized. Fe(NCS)(2)(OCMe(2))(2) exhibits metamagnetic-like behavior, and orders as an antiferromagnet at 6 K. The Mn and Cr compounds are antiferromagnets with T(c) of 30 and 50 K, respectively, with J/k(B) = -3.5 (-2.4 cm(-1)) and -9.9 K (-6.9 cm(-1)), respectively, when fit to one-dimensional (1-D) Fisher chain model (H = -2JS(i)·S(j)). Co(NCS)(2) was prepared by a new synthetic route, and powder diffraction was used to determine its structure to be a two-dimensional (2-D) layer with μ(N,S,S)-NCS motif, and it is an antiferromagnet (T(c) = 22 K; θ = -33 K for T > 25 K). M(NCS)(2)(OCMe(2))(2) (M = Fe, Mn) and Co(NCS)(2) react with (NBu(4))(TCNE) in dichloromethane to form M(TCNE)[C(4)(CN)(8)](1/2), and in acetone to form M[C(4)(CN)(8)](OCMe(2))(2) (M = Fe, Mn, Co). These materials possess μ(4)-[C(4)(CN)(8)](2-) that form 2-D layered structural motifs, which exhibit weak antiferromagnetic coupling. Co(TCNE)[C(4)(CN)(8)](1/2) behaves as a paramagnet with strong antiferromagnetic coupling (θ = -50 K).     

Mechanochemical reactions of coordination polymers by grinding with KBr

Grinding of a one-dimensional (1-D) ladder coordination polymer (CP), [Zn(μ-CH(3)CO(2))(CF(3)CO(2))bpe] (1), and a hydrogen-bonded 1-D CP, [Cd(CH(3)CO(2))(2)bpe(H(2)O)] (2), with KBr resulted in the exchange of carboxylate by bromide ions and the formation of 1-D zigzag and 2-D CPs respectively.