Beta-gamma radiation from leaching resistant glasses containing uranium ions

The β and γ decay of uranium atoms from xUO₃(100 - x)[3B₂O₃ · MO] glass systems, where M=Sr or Pb and 0 ≤ × ≤ 20 mol%, is investigated. The γ decay data are very close to each other, for the same UO₃ contents, in both the systems. The composition dependence of the β decay exhibits a lower slope in the lead borate matrix than in the strontium borate matrix. The ratio between the β activity of samples with the same uranium ion concentrations in the two investigated glass systems is a function of the x values. The results are correlated with the amount of radioactive nuclides and with the structural environments of the radionuclides. The leaching treatment in water at temperatures below 100°C evidenced no aqueous dissolution of glass samples.     

Enhancing self-scheduling algorithms via synchronization and weighting

Existing dynamic self-scheduling algorithms, used to schedule independent tasks on heterogeneous clusters, cannot handle tasks with dependencies because they lack the support for internode communication. To compensate for this deficiency we introduce a synchronization mechanism that provides inter-processor communication, thus, enabling self-scheduling algorithms to handle efficiently nested loops with dependencies. We also present a weighting mechanism that significantly improves the performance of dynamic self-scheduling algorithms. These algorithms divide the total number of tasks into chunks and assign them to processors. The weighting mechanism adapts the chunk sizes to the computing power and current run-queue state of the processors. The synchronization and weighting mechanisms are orthogonal, in the sense that they can simultaneously be applied to loops with dependencies. Thus, they broaden the application spectrum of dynamic self-scheduling algorithms and improve their performance. Extensive testing confirms the efficiency of the synchronization and weighting mechanisms and the significant improvement of the synchronized–weighted versions of the algorithms over the synchronized-only versions.     

Displaced fractures of the middle third of the forearm in children. The therapeutic considerations]

There been studied 100 cases of fractures of the middle third of both bones of forearm in child for to assess the correctitude of the therapy, based on the analysis of results. The most correct surgical techniques consist of osteosynthesis with Kirschner wire of the both bones, knowing the particularities of the fracture linea in child and the minimal tissues' damages. In the child younger then 10 years old, the open reduction is rarely necessary. Any displaced fracture of middle third of both bones of forearm, whatever the age of the child would be orthopedically reduced, before performing the surgical therapy. The unstable osteosynthesis such as simple screw "osteosynthesis" with wire or thread are contraindicated.     

Synthesis of nanozirconooligocarbosilanes

We describe the first chlorine-free synthesis of nanozirconooligocarbosilanes through thermal cocondensation of low-molecular oligocarbosilanes and zirconium tetrakis(diethylamide). The starting reagents, reaction intermediates, and final products have been characterized by ¹H, ¹³C, and ²⁹Si nuclear magnetic resonance, UV and IR spectroscopy, gel-permeation chromatography, thermogravimetry, transmission electron microscopy (TEM), and elemental analysis. The synthesized nanozirconooligocarbosilanes have been used to fabricate ceramic fibers and matrices through thermal and chemical processing. TEM results demonstrate that the particles of zirconium and products of its reactions with silicon, carbon, and nitrogen range in size from 10 to 20 nm in the oligomers and from 20 to 30 nm in the ceramics.     

Betulinic Acid in Complex with a Gamma-Cyclodextrin Derivative Decreases Proliferation and in Vivo Tumor Development of Non-Metastatic and Metastatic B164A5 Cells

Betulinic acid, a very promising anti-melanoma agent, has very low water solubility that causes low bioavailability. To overcome this inconvenience, a highly water-soluble cyclodextrin was used (octakis-[6-deoxy-6-(2-sulfanyl ethanesulfonic acid)]-γ-cyclodextrin). The complex was physico-chemically analyzed using differential scanning calorimetry (DSC), X-ray and scanning electron microscopy (SEM) methods and then in vitro tested for its antiproliferative activity by the MTT assay and by cell cycle analysis. Finally, the complex was tested in vivo using an animal model of murine melanoma developed in C57BL/6J mice, where it caused a reduction in tumor volume and weight. The study revealed the beneficial influence of betulinic acid inclusion into the cyclodextrin in terms of antiproliferative activity and in vivo tumor development.     

Cell therapy using an array of ultrathin hollow microneedles

Microsystem Technologies - Cell transplantation traditionally employs needles to inject donor cells into tissues to treat certain diseases. However, it is difficult for the current method to...     

Structural investigation of xFe2O3 · (100 − x)[P2O5 · TeO2] glass system by FT-IR study and EPR spectroscopy

Glasses from xFe₂O₃ · (100 − x)[P₂O₅ · TeO₂] system, with 0 ≤ x ≤ 50 mol%, were investigated by X-ray diffraction, FT-IR and EPR spectroscopies. The XRD patterns show a vitreous state of studied samples for x ≤ 35 mol% Fe₂O₃. The FT-IR spectrum of the P₂O₅ · TeO₂ glass matrix reveals a structure formed from PO₄, TeO₄ and TeO₃ units. The addition and the increasing of Fe₂O₃ content modify progressively the structure of the glass matrix. The local structure in the investigated glasses was revealed by means of EPR using Fe³⁺ (3d⁵; ⁶S_5/2) ions as paramagnetic probes. The EPR spectra present two resonance absorption lines characteristic to Fe³⁺ ions centred at g_eff ≈ 2.0, for 0.5 ≤ x ≤ 35 mol% and g_eff ≈ 4.3, for 0.5 ≤ x ≤ 5 mol%. The variation of the EPR parameters, the intensity and line-width of these absorption lines, with iron ions composition has been followed.