The design of a source to simulate the gamma-ray spectrum emitted by a radioisotope thermoelectric generator

A simulated source was designed to duplicate the gamma spectrum of a uniform cylindrical 2200-watt Pu02 radioisotope thermoelectric generator containing 81% Pu-238 and 1.2 ppm Pu-236. Gamma rays from the decay of Pu-238, Am-241, Pu-239, and the 0-18(alpha,n)Ne-21 reaction were catalogued in broad energy groups. Two 46- and one 22-mc Th-228 sources provided simulation at various times in the life of the fuel capsule up to 18 years, which covers the time span of an outer planet mission. Emission from Th-228 represents the overwhelming contribution of the gamma spectrum after the first few years. The sources, in the form of 13-inch rods, were placed in a concentric hole in a cylinder of depleted uranium, which provided shielding equivalent to the self-shielding of the fuel capsule. The thickness of the U-238 cylinder (0.55cm) was determined by Monte Carlo calculations to insure that the spectrum emerging from the simulated source matched that of the fuel capsule

Oxide-Supported IrNiO_x Core-Shell Particles as Efficient, Cost-Effective, and Stable Catalysts for Electrochemical Water Splitting

Active and highly stable oxide-supported IrNiOx core–shell catalysts for electrochemical water splitting are presented. IrNix@IrOx nanoparticles supported on high-surface-area mesoporous antimony-doped tin oxide (IrNiOx /Meso-ATO) were synthesized from bimetallic IrNix precursor alloys (PA-IrNix /Meso-ATO) using electrochemical Ni leaching and concomitant Ir oxidation. Special emphasis was placed on Ni/NiO surface segregation under thermal treatment of the PA-IrNix /Meso-ATO as well as on the surface chemical state of the particle/oxide support interface. Combining a wide array of characterization methods, we uncovered the detrimental effect of segregated NiO phases on the water splitting activity of core–shell particles. The core–shell IrNiOx /Meso-ATO catalyst displayed high water-splitting activity and unprecedented stability in acidic electrolyte providing substantial progress in the development of PEM electrolyzer anode catalysts with drastically reduced Ir loading and significantly enhanced durability

Hybrid sol–gel double metal cyanide catalysts for the copolymerisation of styrene oxide and CO₂

Hybrid sol–gel catalysts of zinc hexacyanocobaltate and SiO2 were prepared by co-precipitation of the double metal cyanide with silica. Hybrid catalysts prepared at moderately acidic conditions showed the best performance with respect to activity, selectivity and stability. The hybrid sol–gel materials displayed high catalytic activity for the copolymerisation of styrene oxide and carbon dioxide (up to 650 molSO (molZn h)−1) and high productivity (575 gPolymer gCatalyst −1). They also displayed good selectivity to the polymeric product (80–87%), while only little cyclic styrene carbonate was formed as side product. A detailed electron microscopy study of the hybrid sol–gel materials showed that the active phase consisted of thin platelets containing the metals in a molar ratio nZn/nCo = 2.1, whereby the double metal cyanide was closely associated with silica

First analysis of the Severe Paediatric Asthma Collaborative in Europe registry.

New biologics are being continually developed for paediatric asthma, but it is unclear whether there are sufficient numbers of children in Europe with severe asthma and poor control to recruit to trials needed for registration. To address these questions, the European Respiratory Society funded the Severe Paediatric Asthma Collaborative in Europe (SPACE), a severe asthma registry. We report the first analysis of the SPACE registry, which includes data from 10 paediatric respiratory centres across Europe. Data from 80 children with a clinical diagnosis of severe asthma who were receiving both high-dose inhaled corticosteroid and long-acting β2-agonist were entered into the registry between January 2019 and January 2020. Suboptimal control was defined by either asthma control test, or Global Initiative for Asthma criteria, or ≥2 severe exacerbations in the previous 12 months, or a combination. Overall, 62 out of 80 (77%) children had suboptimal asthma control, of whom 29 were not prescribed a biologic. However, in 24 there was an option for starting a licensed biologic. 33 children with suboptimal control were prescribed a biologic (omalizumab (n=24), or mepolizumab (n=7), or dupilumab (n=2)), and for 29 there was an option to switch to a different biologic. We conclude that the SPACE registry provides data that will support the planning of studies of asthma biologics. Not all children on biologics achieve good asthma control, and there is need for new trial designs addressing biologic switching

The electronic structure of iridium oxide electrodes active in water splitting

Iridium oxide based electrodes are among the most promising candidates for electrocatalyzing the oxygen evolution reaction, making it imperative to understand their chemical/electronic structure. However, the complexity of iridium oxide's electronic structure makes it particularly difficult to experimentally determine the chemical state of the active surface species. To achieve an accurate understanding of the electronic structure of iridium oxide surfaces, we have combined synchrotron-based X-ray photoemission and absorption spectroscopies with ab initio calculations. Our investigation reveals a pre-edge feature in the O K-edge of highly catalytically active X-ray amorphous iridium oxides that we have identified as O 2p hole states forming in conjunction with IrIII. These electronic defects in the near-surface region of the anionic and cationic framework are likely critical for the enhanced activity of amorphous iridium oxides relative to their crystalline counterparts

A Real-Time PCR Antibiogram for Drug-Resistant Sepsis

Current molecular diagnostic techniques for susceptibility testing of septicemia rely on genotyping for the presence of known resistance cassettes. This technique is intrinsically vulnerable due to the inability to detect newly emergent resistance genes. Traditional phenotypic susceptibility testing has always been a superior method to assay for resistance; however, relying on the multi-day growth period to determine which antimicrobial to administer jeopardizes patient survival. These factors have resulted in the widespread and deleterious use of broad-spectrum antimicrobials. The real-time PCR antibiogram, described herein, combines universal phenotypic susceptibility testing with the rapid diagnostic capabilities of PCR. We have developed a procedure that determines susceptibility by monitoring pathogenic load with the highly conserved 16S rRNA gene in blood samples exposed to different antimicrobial drugs. The optimized protocol removes heme and human background DNA from blood, which allows standard real-time PCR detection systems to be employed with high sensitivity (<100 CFU/mL). Three strains of E. coli, two of which were antimicrobial resistant, were spiked into whole blood and exposed to three different antibiotics. After real-time PCR-based determination of pathogenic load, a ΔCt<3.0 between untreated and treated samples was found to indicate antimicrobial resistance (P<0.01). Minimum inhibitory concentration was determined for susceptible bacteria and pan-bacterial detection was demonstrated with 3 Gram-negative and 2 Gram-positive bacteria. Species identification was performed via analysis of the hypervariable amplicons. In summary, we have developed a universal diagnostic phenotyping technique that assays for the susceptibility of drug-resistant septicemia with the speed of PCR. The real-time PCR antibiogram achieves detection, susceptibility testing, minimum inhibitory concentration determination, and identification in less than 24 hours

Efficacy of bacterial ribosomal RNA-targeted reverse transcription-quantitative PCR for detecting neonatal sepsis: a case control study

<p>Abstract</p> <p>Background</p> <p>Neonatal sepsis is difficult to diagnose and pathogens cannot be detected from blood cultures in many cases. Development of a rapid and accurate method for detecting pathogens is thus essential. The main purpose of this study was to identify etiological agents in clinically diagnosed neonatal sepsis using bacterial ribosomal RNA-targeted reverse transcription-quantitative PCR (BrRNA-RT-qPCR) and to conduct comparisons with the results of conventional blood culture. Since BrRNA-RT-qPCR targets bacterial ribosomal RNA, detection rates using this approach may exceed those using conventional PCR.</p> <p>Methods</p> <p>Subjects comprised 36 patients with 39 episodes of suspected neonatal sepsis who underwent BrRNA-RT-qPCR and conventional blood culture to diagnose sepsis. Blood samples were collected aseptically for BrRNA-RT-qPCR and blood culture at the time of initial sepsis evaluation by arterial puncture. BrRNA-RT-qPCR and blood culture were undertaken using identical blood samples, and BrRNA-RT-qPCR was performed using 12 primer sets.</p> <p>Results</p> <p>Positive rate was significantly higher for BrRNA-RT-qPCR (15/39, 38.5%) than for blood culture (6/39, 15.4%; p = 0.0039). BrRNA-RT-qPCR was able to identify all pathogens detected by blood culture. Furthermore, this method detected pathogens from neonates with clinical sepsis in whom pathogens was not detected by culture methods.</p> <p>Conclusions</p> <p>This RT-PCR technique is useful for sensitive detection of pathogens causing neonatal sepsis, even in cases with negative results by blood culture.</p

Дифференциальный хемореактомный анализ глюкозамина сульфата и нестероидных противовоспалительных препаратов: перспективные синергичные комбинации

Glucosamine sulfate (GS) is essential for the regeneration of cartilaginous tissue and, in addition, it has anti-inflammatory properties comparable to those of nonsteroidal anti-inflammatory drugs (NSAIDs). Clinical trials indicate the synergism between GS and NSAIDs in osteoarthritis (OA) and other joint diseases.Objective: to estimate the degree of synergism between different combinations of GS and NSAIDs.Material and methods. A differential chemoreactome analysis was employed to evaluate the effects of GS and seven agents from the class of NSAIDs, such as ketorolac, nimesulide, diclofenac, meloxicam, dexketoprofen, celecoxib, and etoricoxib, for estimating the degree of synergism between different combinations of GS and NSAIDs.Results and discussion. Dexketoprofen is shown to enhance most effectively the anti-inflammatory properties of GS as compared to ketorolac that does this to a lesser extent. The drug should be practically used as follows: the most effective combination (GS + dexketoprofen (or GS + ketorolak) is taken at week 1 of treatment for rapid pain elimination; thereafter there may be a combination of GS and NSAIDs, the intake of which is associated with minimal adverse reactions for a longer time.Conclusion. The investigation has shown that the coadministration of GS and NSAIDs is promising in treating joint diseases. Глюкозамина сульфат (ГС) необходим для регенерации хрящевой ткани, кроме того, он обладает противовоспалительными свойствами, сравнимыми с таковыми нестероидных противовоспалительных препаратов (НПВП). Клинические исследования указывают на синергизм действия ГС и НПВП при остеоартрите (ОА) и при других заболеваниях суставов.Цель исследования – оценка степени синергизма различных комбинаций ГС и НПВП.Материал и методы. Проведен дифференциальный хемореактомный анализ эффектов ГС и семи средств класса НПВП (кеторолак, нимесулид, диклофенак, мелоксикам, декскетопрофен, целекоксиб, эторикоксиб) для определения степени синергизма различных комбинаций ГС и НПВП.Результаты и обсуждение. Показано, что декскетопрофен (и в меньшей степени кеторолак) наиболее эффективно усиливают противовоспалительные свойства ГС. Для использования на практике рекомендован следующий подход: на 1-й неделе лечения для быстрого устранения болевого синдрома назначается наиболее эффективная комбинация – ГС + декскетопрофен (либо ГС + кеторолак), после чего можно использовать комбинацию ГС с НПВП, прием которого в течение более длительного времени сопряжен с минимальными побочными эффектами.Выводы. Результаты исследования показали, что совместное использование ГС и НПВП при патологии суставов является перспективным.

Astrocyte-Derived Tissue Transglutaminase Interacts with Fibronectin: A Role in Astrocyte Adhesion and Migration?

An important neuropathological feature of neuroinflammatory processes that occur during e.g. Multiple Sclerosis (MS) is the formation of an astroglial scar. Astroglial scar formation is facilitated by the interaction between astrocytes and extracellular matrix proteins (ECM) such as fibronectin. Since there is evidence indicating that glial scars strongly inhibit both axon growth and (re)myelination in brain lesions, it is important to understand the factors that contribute to the interaction between astrocytes and ECM proteins. Tissue Transglutaminase (TG2) is a multifunctional enzyme with an ubiquitous tissue distribution, being clearly present within the brain. It has been shown that inflammatory cytokines can enhance TG2 activity. In addition, TG2 can mediate cell adhesion and migration and it binds fibronectin with high affinity. We therefore hypothesized that TG2 is involved in astrocyte-fibronectin interactions. Our studies using primary rat astrocytes show that intracellular and cell surface expression and activity of TG2 is increased after treatment with pro-inflammatory cytokines. Astrocyte-derived TG2 interacts with fibronectin and is involved in astrocyte adhesion onto and migration across fibronectin. TG2 is involved in stimulating focal adhesion formation which is necessary for the interaction of astrocytes with ECM proteins. We conclude that astrocyte-derived TG2 contributes to the interaction between astrocytes and fibronectin. It might thereby regulate ECM remodeling and possibly glial scarring