Point Defect Study in Fe75Al25 and Fe70Al25X5 X=(Cr, Ni) Alloys as a Function of Thermal Treatment by Positron Lifetime Spectroscopy

AbstractPositron lifetime spectroscopy (PALS) is employed to study retained vacancies in Fe75Al25 and Fe70Al25X5 X= (Cr, Ni) after various thermal treatments. The PALS spectra were analyzed with the two states trapping model. The positron lifetime in defects suggests that they are Fe-monovacancies. The vacancy concentration, determined by the rates of trapping positrons to vacancies, strongly depends on the cooling rate of the sample and the ternary addition. An addition of Cr lowers, whereas an addition of Ni increases the concentration of the retained vacancies in relation to Fe75Al25 samples after the same heat treatment

Surface concentration of defects at grain boundaries in sintered alumina determined by positron annihilation lifetime spectroscopy

Sintered alumina samples of grain diameters spanning from 1.2 to 4: 5 ñm have been investigated by positron annihilation lifetime spectroscopy. One series of samples was produced from material containing about 150 ppm impurities (mainly SiO 2 ). T he second one was made from material having about 2700 ppm of various elements (SiO 2 , MgO , CaO). Two models of positron trapping at grain boundari es are compared : The first one relates to the diffusion -limited regime ; and the other one - to the transition -limited regime of trapping. As a result the relative change of surface concentration of defects at grain boundarie s is determined. Additionally , the positron diffusion constant in bulk alumina at room temperature, D + = 0: 3 6 Ï 10 cm 2 /s, is estimated

The bidirectional tumor - mesenchymal stromal cell interaction promotes the progression of head and neck cancer

Introduction: Mesenchymal stromal cells (MSC) are an integral cellular component of the tumor microenvironment. Nevertheless, very little is known about MSC originating from human malignant tissue and modulation of these cells by tumor-derived factors. The aim of this study was to isolate and characterize MSC from head and neck squamous cell carcinoma (HNSCC) and to investigate their interaction with tumor cells. Methods: MSC were isolated from tumor tissues of HNSCC patients during routine oncological surgery. Immunophenotyping, immunofluorescence and in vitro differentiation were performed to determine whether the isolated cells met the consensus criteria for MSC. The cytokine profile of tumor-derived MSC was determined by enzyme-linked immunosorbent assay (ELISA). Activation of MSC by tumor-conditioned media was assessed by measuring cytokine release and expression of CD54. The impact of MSC on tumor growth in vivo was analyzed in a HNSCC xenograft model. Results: Cells isolated from HNSCC tissue met the consensus criteria for MSC. Tumor-derived MSC constitutively produced high amounts of interleukin (IL)-6, IL-8 and stromal cell-derived factor (SDF)-1α. HNSCC-derived factors activated MSC and enhanced secretion of IL-8 and expression of CD54. Furthermore, MSC provided stromal support for human HNSCC cell lines in vivo and enhanced their growth in a murine xenograft model. Conclusions: This is the first study to isolate and characterize MSC from malignant tissues of patients with HNSCC. We observed cross-talk of stromal cells and tumor cells resulting in enhanced growth of HNSCC in vivo

Genetic algorithms for positron lifetime data

Recently, genetic algorithms have been applied for ultrafast optical spectrometry in systems with several convoluted lifetimes. We apply these algorithms and compare the results with POSFIT (by Kirkegaard and Eldrup) and LT programme (by Kansy). The analysis was applied to three types of samples: molybdenum monocrystals, Czochralski-grown silicon with oxygen precipitates, Si with under-surface cavities obtained by He + H ion co- implantation. In all three tests, the genetic algorithm performs very well, in particular for short lifetimes. Further developments to model the resolution function in genetic algorithms are needed

Типовая учебная программа по учебной дисциплине для специальности: 1-23 01 08 Журналистика (по направлениям), направление специальности 1-23 01 08-02 Журналистика (аудиовизуальная)

Enhancement of soft magnetic properties in the selected group of amorphous alloys was examined by different experimental methods. It was shown that permeability for annealed samples (at Ta for 1 h; 300 K < Ta < 900 K) plotted vs. Ta shows a maximum at which is 700, 725, 725, and 750 K for Fe82Nb2B14Y2, Fe82Nb2B14Gd2, Fe82Nb2B14Tb2 and Fe82Nb2B14Dy2 alloy, respectively. For samples after the optimization annealing permeability is at least 10 times higher than in the as-quenched state. The optimized microstructure is free of iron nanograins and corresponds to so-called relaxed amorphous phase

Photo-CIDNP in the reaction center of the diatom Cyclotella meneghiniana observed by 13C MAS NMR

Solid state NMR/Biophysical Organic Chemistr

Das Tumormikromilieu bei Speicheldrüsenkarzinomen – mögliche Konsequenzen für neue Therapiekonzepte

Hintergrund Speicheldrüsenkarzinome („salivary gland carcinomas“, SGC) sind seltene Tumoren, die aufgrund ihrer histologischen Vielfalt und den in Abhängigkeit vom Subtyp unterschiedlichen Krankheitsverläufen eine Herausforderung für Diagnostik und Therapie darstellen. Über die Zusammensetzung des Tumormikromilieus (TME) bei SGC ist bislang wenig bekannt. Ein umfassenderes Verständnis der relevanten molekularen Veränderungen und immunologischen Prozesse des Tumors sowie des umgebenden Stromas könnte dazu beitragen, die therapeutische Effizienz – beispielsweise durch eine adjuvante Immunmodulation – zu verbessern. Methoden In diesem Manuskript wurden Ergebnisse aus Studien zusammengefasst, die sich mit der Zusammensetzung des TME bei SGC beschäftigen. Ergebnisse Das Immunzellinfiltrat der verschiedenen Tumorentitäten ist unterschiedlich. Bei einem Drittel der SGC wurde eine Expression des Oberflächenzellrezeptors LAG3 („lymphocyte activation gene 3“) auf tumorinfiltrierenden Lymphozyten beobachtet. LAG3 inhibiert – ähnlich wie CTLA‑4 („cytotoxic T‑lymphocyte antigen 4“) und PD‑1 („programmed cell death 1 protein“) – die zelluläre Proliferation, Aktivierung und Homöostase von antitumoral wirksamen T‑Zellen. Höhere Expressionen sind dabei insbesondere bei den prognostisch ungünstigeren Entitäten wie den Speichelgangkarzinomen und Adenokarzinomen NOS („not otherwise specified“) zu beobachten. Schlussfolgerungen LAG3 ist insbesondere bei aggressiven Entitäten und fortgeschrittenen Tumoren nachzuweisen. Folglich könnte eine Therapie mit LAG3-Inhibitoren eine Therapie bei fortgeschrittenen und metastasierten SGC unterstützen

Higher Programmatic Volume in Neonatal Heart Surgery Is Associated With Lower Early Mortality

BACKGROUND: The early results of congenital heart surgery in neonates remain a challenge. We sought to determine the nature of the association between annual center volume of neonatal cardiac surgery and operative mortality using a multicenter cohort. METHODS: The dataset consists of 27,556 neonatal procedures performed between 1999 and 2015 in 90 centers participating in the European Congenital Heart Surgeons Association database. Centers with mean annual volume load of six or more that submitted data for at least 3 consecutive years were included. World Bank annual gross national index per capita was utilized as an indicator of temporal national affluence. Multilevel logistic regression was used to create a model including the significant risk factors and to calculate odds ratios for operative mortality. Iterative modeling of the dataset incrementally excluding centers with lower annual caseload was used to identify the relationship between annual volume and mortality. RESULTS: In the model thus calculated including The Society of Thoracic Surgeons-European Association for Cardio-Thoracic Surgery (STAT) mortality score, operative weight and age, noncardiac genetic anomalies, and annual volume of operations were independent risk factors for operative mortality in the analysis of the entire cohort. In the model containing these variables, annual gross national index and year of surgery were not significantly associated with mortality. In the iterative process, annual volume ceased to be a risk factor when units operating on fewer than 60 neonates annually were excluded. CONCLUSIONS: In neonatal congenital heart surgery, the risk of operative death decreased with the increase of volume load. The cutoff point in this cohort was a mean annual volume of 60 neonatal operations per year.info:eu-repo/semantics/publishedVersio