Synthesis and Structure of Complexes of Np(V) Perchlorate and Np(V) Chloride with Urea

The crystal structure of [NpO₂{OC(NH₂)₂}₅]ClO₄·H₂O and [NpO₂Cl{OC(NH₂)₂}₄] was studied by X-ray diffraction. The electronic absorption spectra of these complexes were recorded. The coordination polyhedron of Np in both complexes is a distorted pentagonal bipyramid. There is no cation-cation interaction of neptunyl cations in these complexes.     

Superior mesenteric artery syndrome presenting with acute massive gastric dilatation

A 14-year-old girl presenting with acute massive gastric dilatation secondary to duodenal obstruction by the superior mesenteric artery is described. The diagnosis was facilitated by contrast-enhanced abdominal computerized tomography. She was successfully treated by gastrostomy and subsequent duodenal derotation. This unique presentation of the superior mesenteric artery syndrome is discussed.     

The significance of gastric helicobacteriosis in the genesis hemorrhage from duodenal peptic ulcer

Based on a comprehensive analysis of findings from examination and surgical treatment of 196 patients with bleeding pyloroduodenal ulcers, it was found out that patients with concurrent helicobacteriosis of the stomach are prone to more unfavourable course of their illness, which fact is evidenced by a greater loss of blood and higher risk for bleeding recurrences. A classification is proposed by the authors, taking advantage of the data from endoscopic, microscopic and immunoenzymatic techniques, with the purpose of providing an assessment of degree of severity of helicobacteriosis of the stomach.     

Epidemiology of toxic shock syndrome toxin-1 production in Staphylococcus aureus strains isolated in Denmark between 1959 and 1990

A total of 436 Staphylococcus aureus bacteremia strains isolated between 1959 and 1990 were tested for the production of toxic shock syndrome toxin-1 (TSST-1) by a semiquantitative reversed passive latex agglutination test. TSST-1 production was found in 147/260 (57%) of phage group I strains, excluding the "80" complex, and in 17/176 (10%) of non-group I strains. Strains of the 52, 52A, 80, 81 complex ("80" complex), constituting a subgroup of group I, did not have the same high frequency of TSST-1 production as the rest of group I strains (4% versus 57%). The "80" complex has almost disappeared in Denmark. TSST-1 production was found with the same high frequency among group I strains from the beginning (1959) and throughout the observation period. The TSST-1 production was associated with the phages 29 and/or 52, which in turn lysed 95% of group I strains. The TSST-1 production was quantitatively greater in the phage group I strains than in the non-group I strains. TSST-1 production of the bacteremia strains was not correlated to the clinical parameters: mortality, age, gender, bacterial focus, underlying diseases, or whether the infection was hospital or community acquired.     

Effect of ionizing radiation on the extraction of Am(III) with <Emphasis Type="Italic">p-tert</Emphasis>-butylthiacalix[4]arene from alkaline carbonate solutions

The effect of γ-irradiation of tert-butylthiacalix[4]arene (TCA) solutions in m-nitrobenzotrifluoride (NBTF) and tetrachloroethylene (TCE) on the extraction of ²⁴¹Am from alkaline carbonate solutions was studied. TCA itself remains stable upon γ-irradiation of its solutions in NBTF to a dose of 200 kGy, but the diluent undergoes strong degradation. The radiation resistance of TCA in TCE is considerably lower: A dose of 70 kGy causes complete degradation of TCA. In the TCA–TCE–aqueous phase system, sulfate ions appear upon γ-irradiation as the final product of the extractant radiolysis. A large number of γ-radiolysis products of TCE and TCA were detected by HPLC and GCMS. The products of radiolysis of TCA in TCE, compared to the initial extractant, have lower molecular mass and higher polarity. The results show that chlorinated diluents are not promising diluents for thiacalixarene in extraction processing of alkaline high-level waste.     

Somatic mosaicism in a patient with neurofibromatosis type 1

Using loss of heterozygosity analysis, a method designed to detect moderate to large gene deletions, we have identified a new-mutation neurofibromatosis type 1 (NF1) patient who is somatically mosaic for a large maternally derived deletion in the NF1 gene region. The deletion extends at least from exon 4 near the 5' end of the gene to intron 39 near the 3' end. The gene-coding region is, therefore, mostly or entirely deleted, encompassing a loss of > or = 100 kb. We hypothesize that the deletion occurred at a relatively early developmental timepoint, since signs of NF1 in this patient are not confined to a specific body region, as seen in "segmental" NF, and since both mesodermally and ectodermally derived cells are affected. This report provides the first molecular evidence of somatic mosaicism in NF1 and, taken together with a recent report of germ-line mosaicism in NF1, adds credence to the concept that mosaicism plays an important role in phenotypic and genetic aspects of NF1 and may even be a relatively common phenomenon.     

Synthesis of New Crystalline Pu(V) Compounds from Solutions: V. Crystal Structure of [Co(NH3)6][PuO2(C2O4)2] · 3H2O

The compound [Co(NH₃)₆][PuO₂(C₂O₄)₂] · 3H₂O was studied by single crystal X-ray diffraction. The structure contains dimeric complex anions [PuO₂(C₂O₄)₂] ₂ ⁶⁻ in which the coordination polyhedra of the Pu atoms are distorted pentagonal bipyramids sharing a common equatorial edge. In going from [Co(NH₃)₆] · [NpO₂(C₂O₄)₂] · 3H₂O to [Co(NH₃)₆][PuO₂(C₂O₄)₂] · 3H₂O, the An-O distances, both axial (in the actinyl group) and equatorial, decrease virtually isotropically. __________ Translated from Radiokhimiya, Vol. 47, No. 5, 2005, pp. 419–422. Original Russian Text Copyright ? 2005 by Grigor'ev, Antipin, Krot, Bessonov.     

Improvement of bottom structure of a production block in ore drawing using load–haul–dumpers

High-rate ore drawing with a single drawpoint requires stable structure of the horizon bottom in block caving of ore. Application of load–haul–dumpers (LHD) conditions longer spacing of drawpoints, which worsens quality of ore drawing under caved rock. Adequate structures of trench bottoms of ore drawing levels are developed for LHD systems. Relations are set between the limit spacing of drawpoints along the length of the trench and the height of the caved level to define mutual influence of the drawpoints.     

Optimal combination technology for high-grade quartz production based on modeling

The article describes the applied research findings on selecting a resource-saving technology to ensure drastic reduction in loss of high-grade Kyshtym quartz. The economical–mathematical modeling yields relationships between mine efficiency, ground conditions, mine design and technology factors, and the optimal variant of a combination mining technology is determined using the maximum profit criterion. Full-scale physical simulation of closed-spaced charge blasting effect on reduction in overgrinding of quartz is discussed. Drilling and blasting pattern for experimental breaking of quartz by explosions is determined.     

MODELLING OF MICROSTRUCTURE EVOLUTION AND PROPERTIES OF LOW-CARBON STEELS

1.IntroductionMicrostructureprocessmodelsareincreasinglyonhotstriprollingofste.l[1--7].Thesemodelsfrequentlyincorporateagreatdealofempiricismwithcomparativelytightprocessrangesofapplicability.Morefundamentallybasedprocessmodelsarerequiredtodeveloppredictivetoolstooptimizetheproductionforawiderangeofmilldesignsandprocessingconditions.Theprocessofhotstriprollingoflow--carbonsteelscanbesubdividedintothreeprin-cipalstages:(i)reheating,(n)rollingand(iii)cooling(watercoolingontherun--outtableandsubs…