Design of the shattered pellet injection system for ASDEX Upgrade.

A new shattered pellet injection system was designed and built to perform disruption mitigation experiments on ASDEX Upgrade. The system can inject pellets with diameters of 1, 2, 4, or 8 mm with variable lengths over a range of L/D ratios of ∼0.5-1.5. By using helium or deuterium as propellant gas, the pellets can be accelerated to speeds between 60 and 750 m/s. The velocity range slightly depends on the pellet mass. The injection system is capable of preparing three pellets in separate barrels at the same time. Once accelerated by the propellant gas pulse, the pellets travel through one of three parallel flight tubes. Each flight tube is separated into three sections with increasing diameters of 12, 14, and 16 mm. Two gaps between the sections allow for removal of the propellant gas by expansion into two separate expansions tanks (0.3 and 0.035 m3), pellet observation in the first gap and the torus gate valve in the second. Each flight tube end is equipped with an exchangeable shatter head with different shatter angles, square or circular cross-section, and different lengths. The gas preparation and control systems allow highly automated pellet generation for precision of the pellet composition and an excellent reproducibility of shattered pellet experiments.

Systemic versus Oral and Systemic Antibiotic Prophylaxis (SOAP) study in colorectal surgery: prospective randomized multicentre trial.

BACKGROUND: There is no consensus regarding the role of mechanical bowel preparation (MBP) and oral antibiotic prophylaxis (OABP) in reducing postoperative complications in colorectal surgery. The aim of this study was to examine the effect of OABP given in addition to MBP in the setting of a prospective randomized trial. METHODS: Patients awaiting elective colorectal surgery in four Hungarian colorectal centres were included in this multicentre, prospective, randomized, assessor-blinded study. Patients were randomized to receive MBP with or without OABP (OABP+ and OABP- groups respectively). The primary endpoints were surgical-site infection (SSI) and postoperative ileus. Secondary endpoints were anastomotic leak, mortality, and hospital readmission within 30 days. RESULTS: Of 839 patients assessed for eligibility between November 2016 and June 2018, 600 were randomized and 529 were analysed. Trial participation was discontinued owing to adverse events in seven patients in the OABP+ group (2.3 per cent). SSI occurred in eight patients (3.2 per cent) in the OABP+ and 27 (9.8 per cent) in the OABP- group (P = 0.001). The incidence of postoperative ileus did not differ between groups. Anastomotic leakage occurred in four patients (1.6 per cent) in the OABP+ and 13 (4.7 per cent) in the OABP- (P = 0.02) group. There were no differences in hospital readmission (12 (4.7 per cent) versus 10 (3.6 per cent); P = 0.25) or mortality (3 (1.2 per cent) versus 4 (1.4 per cent); P = 0.39). CONCLUSION: OABP given with MBP reduced the rate of SSI and AL after colorectal surgery with anastomosis, therefore routine use of OABP is recommended.

Simulating the nonlinear interaction of relativistic electrons and tokamak plasma instabilities: Implementation and validation of a fluid model.

For the simulation of disruptions in tokamak fusion plasmas, a fluid model describing the evolution of relativistic runaway electrons and their interaction with the background plasma is presented. The overall aim of the model is to self-consistently describe the nonlinear coupled evolution of runaway electrons (REs) and plasma instabilities during disruptions. In this model, the runaway electrons are considered as a separate fluid species in which the initial seed is generated through the Dreicer source, which eventually grows by the avalanche mechanism (further relevant source mechanisms can easily be added). Advection of the runaway electrons is considered primarily along field lines, but also taking into account the E×B drift. The model is implemented in the nonlinear magnetohydrodynamic (MHD) code jorek based on Bezier finite elements, with current coupling to the thermal plasma. Benchmarking of the code with the one-dimensional runaway electron code go is done using an artificial thermal quench on a circular plasma. As a first demonstration, the code is applied to the problem of an axisymmetric cold vertical displacement event in an ITER plasma, revealing significantly different dynamics between cases computed with and without runaway electrons. Though it is not yet feasible to achieve fully realistic runaway electron velocities close to the speed of light in complete simulations of slowly evolving plasma instabilities, the code is demonstrated to be suitable to study various kinds of MHD-RE interactions in MHD-active and disruption relevant plasmas.

High resolution gamma-ray spectrometer with MHz capabilities for runaway electron studies at ASDEX Upgrade.

A new gamma-ray spectrometer with MHz capabilities has been developed to measure the bremsstrahlung emission spectrum in the gamma-ray energy band generated by MeV range runaway electrons in disruption experiments at ASDEX Upgrade. Properties of the runaway electrons are inferred from the measured bremsstrahlung spectrum by a deconvolution technique, particularly with regard to their maximum energy. Changes induced to the runaway electron velocity space are unambiguously observed both in massive gas injection and resonant magnetic perturbation experiments with the detector.

Effect of Partially Screened Nuclei on Fast-Electron Dynamics.

We analyze the dynamics of fast electrons in plasmas containing partially ionized impurity atoms, where the screening effect of bound electrons must be included. We derive analytical expressions for the deflection and slowing-down frequencies, and show that they are increased significantly compared to the results obtained with complete screening, already at subrelativistic electron energies. Furthermore, we show that the modifications to the deflection and slowing down frequencies are of equal importance in describing the runaway current evolution. Our results greatly affect fast-electron dynamics and have important implications, e.g., for the efficacy of mitigation strategies for runaway electrons in tokamak devices, and energy loss during relativistic breakdown in atmospheric discharges.

Highly efficient dehydrogenation of formic acid in aqueous solution catalysed by an easily available water-soluble iridium(iii) dihydride.

The new water-soluble cis-mer-[IrH2Cl(mtppms)3] (mtppms = monosulfonated triphenylphosphine) was employed as a catalyst for selective decomposition of formic acid to H2 + CO2 in aqueous solution at T = 30-100 °C. The easily synthesized compound showed high catalytic activity (TOF up to 298 000 h(-1)) and could be reused several times with no loss of activity (total TON = 67 650). A sharp maximum in the reaction rate was observed at pH = 3.75; its coincidence with the pKa of formic acid shows that both H(+) or HCOOH and HCOO(-) play important roles in the reaction mechanism.

A comprehensive investigation on the distribution of circulating follicular T helper cells and B cell subsets in primary Sjögren's syndrome and systemic lupus erythematosus.

Follicular T helper (Tfh) cells have a crucial role in regulating immune responses within secondary lymphoid follicles by directing B cell differentiation towards memory B cells and plasma cells. Because abnormal humoral responses are key features in both primary Sjögren's syndrome (pSS) and systemic lupus erythematosus (SLE), the aim of this study was to profile the pathological connection between peripheral Tfh cells and B cells in the two diseases. Twenty-five pSS patients, 25 SLE patients and 21 healthy controls were enrolled into the study. We determined the ratio of circulating Tfh-like cells, their interleukin (IL)-21 production and different B cell subsets by flow cytometry. We observed higher percentages of naive B cells in both diseases, while non-switched and switched memory B cells showed decreased frequencies. The proportions of double-negative B cells and plasmablasts were elevated in SLE and decreased in pSS. The percentages of transitional B cells and mature-naive B cells were higher in SLE. Patients with more severe disease course had an elevated ratio of TFH-like cells and increased IL-21 production. Moreover, expansion of Tfh-like cells correlated positively with parameters related to antibody secretion, including serum immunoglobulin (Ig)G, immune complexes (ICs) and autoantibodies. Correlation analysis between Tfh-like cells and certain B cell subsets revealed possible defects during B cell selection. In conclusion, our observations on the profound expansion of circulating Tfh-like cells and their IL-21 production, along with the characteristic aberrant peripheral B cell distribution in both pSS and SLE, indicate the prominent role of Tfh cell in the regulation of B cell selection.

Therapeutic challenge during the long-term follow-up of a patient with indolent systemic mastocytosis with extensive cutaneous involvement.

From a dermatological aspect, it posed a considerable challenge the skin-limited form of mastocytosis, urticaria pigmentosa and indolent systemic mastocytosis (ISM) with cutaneous lesions. Despite the favourable prognosis, lifelong dermatological control is needed, during which the average symptomatic therapy does not always seem adequate. We report here the case of a female ISM patient with recurrent cutaneous symptoms that impaired her quality of life, with a follow-up time of 27 years. During this long follow-up period, the cutaneous lesions could be controlled by antihistamines, leukotriene antagonists, glucocorticoids, local immunosuppressants or local UV radiation for only relatively short periods. Imatinib mesylate was, therefore, introduced in an attempt to control the cutaneous lesions. Tyrosine kinase inhibition is an unusual dermatological therapeutic option. This case illustrates that imatinib mesylate was a good choice with which to achieve a reduction of the skin lesions in this KIT D816V mutation-negative disease: it led to a temporary appreciable improvement of the patient's quality of life.

Runaway positrons in fusion plasmas.

Runaway positrons can be produced in the presence of runaway electron avalanches in magnetized plasmas. In this Letter, we determine the positron distribution, the fraction of runaway positrons, and the parametric dependences of their synchrotron radiation spectrum. We show that the maximum production occurs around γ(e)≃30, where γ(e) is the Lorentz factor of the fast electrons. For an avalanching positron distribution typical of tokamak plasmas, the maximum of the synchrotron radiation spectrum should be around a micron. The radiated power and spectrum shape are sensitive to the plasma parameters. Apart from its intrinsic interest, detection of radiation from positrons could be a diagnostic tool to understand the properties of the medium they propagate through.

Changes in DRIFT spectra of wood irradiated by lasers of different wavelength.

An exact wavelength separation of the spectrum cannot be accomplished when utilizing common ultraviolet (UV) light sources, so the dependence of photodegradation on wavelength cannot be done directly. The photodegradation of wood resulted in by laser irradiation on various wavelengths can be studied by comparing the changes in the DRIFT spectra of various wood materials. The analysis of the difference spectrum is a widely used method to investigate the changes in the infrared spectrum. As this procedure cannot be used to compare the changes quantitatively, a new indicator was introduced, termed Band Damage Index (BDI). The BDI and the results obtained by its analysis are going to be discussed.

In vivo direct interaction of the antibiotic primycin on a Candida albicans clinical isolate and its ergosterol-less mutant.

Interaction of primycin antibiotic with plasma membrane, and its indirect biological effects were investigated in this study. The antifungal activity of primycin against 13 human pathogenic Candida ATCC and CBS reference species and 74 other Candida albicans clinical isolates was investigated with a microdilution technique. No primycin-resistant strain was detected. Direct interaction of primycin with the plasma membrane was demonstrated for the first time by using an ergosterol-producing strain 33erg+ and its ergosterol-less mutant erg-2. In growth inhibition tests, the 33erg+ strain proved to be more sensitive to primycin than its erg-2 mutant, indicating the importance of the plasma membrane composition in primycin-induced processes. The 64 µg ml-1 (56.8 nM) primycin treatment induced an enhanced membrane fluidity and altered plasma membrane dynamics, as measured by steady-state fluorescence anisotropy applying a trimethylammonium-diphenylhexatriene (TMA-DPH) fluorescence polarization probe. The following consequences were detected. The plasma membrane of the cells lost its barrier function, and the efflux of 260-nm-absorbing materials from treated cells of both strains was 1.5-1.8 times more than that for the control. Depending on the primycin concentration, the cells exhibited unipolar budding, pseudohyphae formation, and a rough cell surface visualized by scanning electron microscopy.

Immunological reconstitution after autologous stem cell transplantation in patients with refractory systemic autoimmune diseases.

OBJECTIVE: High-dose chemotherapy followed by autologous haematopoietic stem cell transplantation (AHSCT) can be a salvage therapy for patients with severe, refractory systemic autoimmune diseases. The function of the newly rebuilt immune system is important, but little is known about immune reconstitution after AHSCT in autoimmune disorders. Our aim was to investigate the repopulation of different lymphocyte subsets in patients with systemic autoimmune diseases after AHSCT. METHODS: Twelve patients with severe refractory, autoimmune diseases were enrolled in the study: four with rheumatoid arthritis (RA), four with systemic sclerosis (SSc), three with systemic lupus erythematosus (SLE), and one with autoimmune overlap syndrome (myositis and RA). After stem-cell mobilization, CD34+ apheresis was carried out, followed by conditioning and AHSCT. After transplantation, peripheral lymphocyte subsets were regularly assessed by flow cytometry. RESULTS: The follow-up time was 24 months. The overall transplantation-related mortality (TRM) was 16.7% and the transplant-related toxicity was 33% 2 years after AHSCT. Regarding the immune reconstitution, CD56+ natural killer (NK) cells appeared in the earliest phase after transplantation, followed by CD8+ T cells. B cells and CD4+ T cells became normal within 150 days. The ratio of naive cells was low 30 days after AHSCT; however, naive B cells regenerated within 2 months whereas the repopulation of naive T cells took longer. After a short increase, the ratio of memory cells decreased 2 months after transplantation. Regulatory T (Treg) cells did not change significantly in the peritransplant period. Altogether approximately 5-6 months were required for the reconstitution of the peripheral immune network. CONCLUSIONS: AHSCT can be a salvage therapeutic modality in autoimmune patients who are refractory to other conventional therapies.

Characterization of stress processes of Phaffia rhodozyma stress-resistant mutant.

A carotenoid-less Phaffia rhodozyma mutant (MCP 325) exhibited significantly higher resistance to oxidative stressors such as menadione, H2O2 and K2Cr2O7 than its astaxanthin-producing parental strain (MCP 324). The absence of carotenoids in the mutant did not explain this phenomenon. The cause of the decreased superoxide, hydroxyl radical and glutathione contents, the increased peroxide concentration and the elevated specific activity of catalase under uninduced conditions may be a second mutation. Peroxide treatment induced specific catalase activity in the mutant but not in the parental strain. Regulation of these processes led to the result that, in spite of the mutations, the two strains exhibited the same multiplication rate and generation time.

Altered T-cell and regulatory cell repertoire in patients with diffuse cutaneous systemic sclerosis.

OBJECTIVES: The aim of this study was to evaluate a wide spectrum of peripheral immune-competent cell types, reflecting overall disturbances in immune homeostasis, characteristic of systemic sclerosis (SSc). We also assessed visceral organ involvement and evaluated the relationship between cell proportions and clinical symptoms of the disease. METHODS: Twenty-one patients with diffuse cutaneous SSc (dcSSc) and 15 healthy individuals participated in the study. Peripheral blood lymphocyte subgroups were quantified by flow cytometry, soluble cytokines were assessed by enzyme-linked immunosorbent assay (ELISA), serum complement levels were measured by nephelometry, and autoantibodies were determined by indirect immunofluorescence staining and ELISA technique. Functional tests of regulatory T (Treg) cells were also carried out. RESULTS: Patients with SSc had higher percentages of activated CD3+/HLA-DR+ T cells. Comparing naive vs. memory subsets of CD4+ and CD8+ T cells, a shift towards central memory phenotype was observed in SSc. Natural killer (NK) and T-helper (Th)17 cell percentages were increased, while NKT, Th1, Treg type 1 (Tr1), and CD4+CD25+ Treg cell percentages were decreased in patients. Moreover, the suppressor activity of CD4+CD25+ Treg cells was lower in SSc. Negative correlations occurred between modified Rodnan skin score (MRSS) and Tr1 cell percentages and between complement levels and CD4+CD25+ Treg cells. We also found decreased interleukin (IL)-10 levels in SSc. CONCLUSIONS: Our data suggest that the increased Th17/CD4+CD25+ Treg ratio and the altered regulatory function of CD4+CD25+ Treg cells play an important role in the development of SSc. Moreover, our study reveals the potential role of the decreased profile of IL-10-producing Tr1 cells in the progression of disproportionate immune responses in SSc.

Cells with regulatory function of the innate and adaptive immune system in primary Sjögren's syndrome.

The aim of the present study was to describe subsets of cells with regulatory properties in primary Sjögren's syndrome (pSS), and to correlate these cell populations with clinical symptoms. Among the 32 investigated patients, 23 had extraglandular manifestations (EGMs), while nine had only glandular symptoms. Twenty healthy individuals served as controls. The percentages of natural killer (NK), natural killer T cells (NK T), interleukin (IL)-10 producing T regulatory type 1 (Tr1) cells and CD4(+)CD25(+) regulatory T cells (T(reg)) cells were determined by flow cytometry and serum cytokine levels of IL-4, IL-6, IL-10, tumour necrosis factor (TNF)-alpha and interferon (IFN)-gamma were evaluated by enzyme-linked immunosorbent assay (ELISA). Functional tests were carried out to assess the suppressor properties of T(reg) cells in patients and controls. Peripheral NK, NK T and Tr1 cell percentages were elevated in pSS, while CD4(+)CD25(+) T(reg) cells showed reduced frequencies in patients compared to controls. In pSS, elevated percentages of NK T, Tr1 and CD4(+)CD25(+) T(reg) cells were observed in patients with EGMs, when compared to patients with sicca symptoms only. CD4(+)CD25(+) T(reg) cell percentages showed a negative correlation with sialometry values. The in vitro functional assay demonstrated lower suppression activity of CD4(+)CD25(+) T(reg) cells in patients compared to controls. Serum IL-6 and TNF-alpha levels were elevated, while IL-10 was decreased in patients compared to controls. Negative correlation was found between IL-10 levels and the percentages of Tr1 cells. Changes in the investigated subsets of regulatory cells in pSS may contribute to the development and progression of the disease.

Aspects of B-cell non-Hodgkin's lymphoma development: a transition from immune-reactivity to malignancy.

The development of B-cell lymphomas is an intricate interplay among various pathogenic factors, leading to a multi-step process, encompassing various stages of B-cell maturation. Besides genetic abnormalities, a variety of environmental and microbial factors, as well as disproportional immune-regulatory processes lead to the malignant transformation. Yet, little is known about the exact chain of events, which lead from the physiological polyclonal B-cell activation as a response to exogenous antigens through oligoclonality to a monoclonal, uncontrolled, malignant B-cell proliferation. The aim of the present review was to summarize the potential harmful steps in the development of B-cell lymphomas, according to conventional and novel theories, and to depict therapeutic regimens presently in use as well as to envision future drug developments, beneficial in the battle against this lymphoid malignancy.

Effect of polar and non-polar carotenoids on Xanthophylomyces dendrorhous membranes by EPR.

The red yeast Xanthophyllomyces dendrorhous is one of the microbiological production systems for natural carotenoids. High-performance liquid chromatography (HPLC) and electron paramagnetic resonance spectroscopy (EPR) experiments were performed on X. dendrorhous membranes in order to study the effect of incorporation rates of different type of carotenoids. In the case of fluid-phase membranes, it was found that polar carotenoids, such as astaxanthin and cis-astaxanthin, increased the EPR order parameter and decreased the motional freedom and phase-transition temperature. In contrast the non-polar carotenoids beta-cryptoxanthin and beta-carotene decreased the EPR order parameter and increased motional freedom and phase-transition temperature. A noteworthy coherence was observed between the polarities of the strains and the phase-transition temperatures.

Electric-field manipulation of spin states in confined non-magnetic/magnetic heterostructures.

The energy spectrum and states of an electron in a non-magnetic/magnetic heterostructure placed between two materials (e.g. oxides) acting as barriers is studied in the presence of a magnetic field perpendicular or parallel to the well. A potential step is formed at the interface between the non-magnetic and magnetic material in the presence of a magnetic field since spin-up electrons see a barrier whereas the spin-down ones see a well. A rich band structure is obtained which can be tuned by a perpendicular electric field. Numerical results are presented for a ZnSe/Zn(1-x)Mn(x)Se heterostructure and their pertinence to spin-polarized transport is pointed out.