Fluctuation spectra of free and supported membrane pairs

Fluctuation spectra of fluid compound membrane systems are calculated. The systems addressed contain two (or more) almost parallel membranes that are connected by harmonic tethers or by a continuous, harmonic confining potential. Additionally, such a compound system can be attached to a supporting substrate. We compare quasi-analytical results for tethers with analytical results for corresponding continuous models and investigate under what circumstances the discrete nature of the tethers actually influences the fluctuations. A tethered, supported membrane pair with similar bending rigidities and stiff tethers can possess a nonmonotonic fluctuation spectrum with a maximum. A nonmonotonic spectrum with a maximum and a minimum can occur for an either free or supported membrane pair of rather different bending rigidities and for stiff tethers. Typical membrane displacements are calculated for supported membrane pairs with discrete or continuous interacting potentials. Thereby an estimate of how close the constituent two membranes and the substrate typically approach each other is given. For a supported membrane pair with discrete or continuous interactions, the typical displacements of each membrane are altered with respect to a single supported membrane, where those of the membrane near the substrate are diminished and those of the membrane further away are enhanced.Comment: 14 pages, 8 figure

Influence of composition and heating schedules on compatibility of FeCrAl alloys with high-temperature steam

FeCrAl alloys are proposed and being intensively investigated as alternative accident tolerant fuel (ATF) cladding for nuclear fission application. Herein, the influence of major alloy elements (Cr and Al), reactive element effect and heating schedules on the oxidation behavior of FeCrAl alloys in steam up to 1500{\deg}C was examined. In case of transient ramp tests, catastrophic oxidation, i.e. rapid and complete consumption of the alloy, occurred during temperature ramp up to above 1200{\deg}C for specific alloys. The maximum compatible temperature of FeCrAl alloys in steam increases with raising Cr and Al content, decreasing heating rates during ramp period and doping of yttrium. Isothermal oxidation resulted in catastrophic oxidation at 1400{\deg}C for all examined alloys. However, formation of a protective alumina scale at 1500{\deg}C was ascertained despite partial melting. The occurrence of catastrophic oxidation seems to be controlled by dynamic competitive mechanisms between mass transfer of Al from the substrate and transport of oxidizing gas through the scale both toward the metal/oxide scale interface.Comment: Submitted to Journal of nuclear materials, accepted recentl

Deposition, characterization and high-temperature steam oxidation behavior of single-phase Ti2_{2}AlC-coated Zircaloy-4

Oxidation of single-phase and dense Ti2AlC coatings with or without a 500 nm TiC diffusion barrier deposited on Zircaloy-4 by annealing of nanoscale multilayer stacks between 800 °C and 1200 °C in high-temperature steam was investigated. Coatings without TiC barrier formed a duplex scale: outer θ-Al2O3 rich layer mixed with TiO2 and inner porous TiO2 layer; correspondingly, a triple-layered scale (θ-Al2O3 + TiO2/θ-Al2O3/TiO2) grew on coatings with barrier at 800 °C. The TiC barrier suppresses the rapid diffusion of Al into the substrate, contributing to improved performance and longer life of Ti2AlC/TiC coatings. However, both coatings demonstrated low protection effect from 1000 °C in steam

Levosimendan, a new therapeutic approach to prevent delayed cerebral vasospasm after subarachnoid hemorrhage?

BACKGROUND Under physiological cerebral conditions, levosimendan, a calcium-channel sensitizer, has a dose-dependent antagonistic effect on prostaglandin F2alpha (PGF)-induced vasoconstriction. This circumstance could be used in antagonizing delayed cerebral vasospasm (dCVS), one of the main complications after subarachnoid hemorrhage (SAH), leading to delayed cerebral ischemia and ischemic neurological deficits. Data already exist that identified neuroprotective effects of levosimendan in a traumatic brain injury model and additionally, it has been proven that this compound prevents narrowing of the basilar artery (BA) luminal area after SAH in an in vitro rabbit model. Takotsubo cardiomyopathy, a severe ventricular dysfunction, is also a well-known complication after SAH, associated with pulmonary edema and prolonged intubation. METHODS The polypeptide endothelin-1 (ET-1) plays a key role in the development of dCVS after SAH. Therefore, the aim of the present investigation was to detect functional interactions between the calcium-sensitizing and the ET-1-dependent vasoconstriction after experimental-induced SAH; interactions between levosimendan and a substrate-specific vasorelaxation in the BA were also examined. It was reviewed whether levosimendan has a beneficial influence on endothelin(A) and/or endothelin(B1) receptors (ET-(A) and ET-(B1) receptors) in cerebral vessels after SAH. We also examined whether this drug could have antagonistic effects on a PGF-induced vasoconstriction. RESULTS Under treatment with levosimendan after SAH, the endothelin system seems to be affected. The ET-1-induced contraction is decreased, not significantly. In addition, we detected changes in the nitric oxide-cyclic guanosine monophosphate (NO-cGMP) pathway. Preincubation with levosimendan causes a modulatory effect on the ET-(B1) receptor-dependent vasorelaxation. It induces an upregulation of the NO-cGMP pathway with a significantly increased relaxation. Even after PGF-induced precontraction a dose-dependent relaxation was registered, which was significantly higher (Emax) and earlier (pD2) compared to the concentration-effect curve without levosimendan. CONCLUSIONS After experimental-induced dCVS, levosimendan seems to restore the well-known impaired function of the vasorelaxant ET-(B1) receptor. Levosimendan also reversed the PGF-induced contraction dose-dependently. Both of these mechanisms could be used for antagonizing dCVS in patients suffering SAH. Levosimendan could even be used additionally in treating patients developing takotsubo cardiomyopathy

Розвиток закордонної релігійної періодики УАПЦ в екзилі на прикладі часопису «Життя і Церква» (The Development of Foreign Religious Periodicals of Ukrainian Autocephalous Orthodox Church in Exile on the Example of the Magazine Life and Church)

Тези присвячені історії української православної церкви закордоном. У центрі уваги – внутрішнє життя церкви, яке репрезентувалося на шпальтах релігійної періодики. На прикладі такого видання як «Життя і церква», з’ясовано інформаційне наповнення публікацій на сторінках подібних журналів. Різноплановий характер поданих у них відомостей є важливим джерелом до вивчення історії українського релігійного життя в діаспорі, особливостей церковного повсякдення. Вони також виступають ключем до розуміння методів збереження національної ідентичності та релігійної самобутності в чужому соціокультурному середовищі. (The author presents the history of the Ukrainian Orthodox Church abroad. The main attention is focused on the internal life of the church, that is represented on the pages of religious periodicals. Using the magazine Life and Church as an example, the author of the research illustrates the typicality of the content of such kind of a publication. Versatile character of the content is an important source to study the history of the Ukrainian religious life in the Diaspora, as well as the features of everyday life in church. They also act as a key to understanding the methods of preserving national and religious identity in another sociocultural environment.

Catalytic Hydrogen Evolution of NaBH4_4 Hydrolysis by Cobalt Nanoparticles Supported on Bagasse-Derived Porous Carbon

As a promising hydrogen storage material, sodium borohydride (NaBH4) exhibits superior stability in alkaline solutions and delivers 10.8 wt.% theoretical hydrogen storage capacity. Nevertheless, its hydrolysis reaction at room temperature must be activated and accelerated by adding an effective catalyst. In this study, we synthesize Co nanoparticles supported on bagasse-derived porous carbon (Co@xPC) for catalytic hydrolytic dehydrogenation of NaBH$_4$. According to the experimental results, Co nanoparticles with uniform particle size and high dispersion are successfully supported on porous carbon to achieve a Co@150PC catalyst. It exhibits particularly high activity of hydrogen generation with the optimal hydrogen production rate of 11086.4 mL$_{H2}$∙min$^{H2}$∙g$_{Co}$$^{H2}$ and low activation energy (E$_{a}$) of 31.25 kJ mol$^{H2}$. The calculation results based on density functional theory (DFT) indicate that the Co@xPC structure is conducive to the dissociation of [BH$_{4}$]$^{-}$, which effectively enhances the hydrolysis efficiency of NaBH$_4$. Moreover, Co@150PC presents an excellent durability, retaining 72.0% of the initial catalyst activity after 15 cycling tests. Moreover, we also explored the degradation mechanism of catalyst performance

Implementation of endoscopic submucosal dissection in Europe: survey after ten ESD expert training workshops 2009 – 2018

Background and aims Transfer of ESD technique for early gastrointestinal cancer from Japan requires expert-supervised experimental training before unsupervised implementation of clinical ESD. Aims To evaluate unsupervised implementation of ESD-intention-to-treat (-ITT). Methods ESD Workshops (in-vivo porcine model) lasted 3.3 days including one day theory for 177 participants from 135 Western referral centers. A questionnaire was sent to the senior participant of all 135 centers. Design Cross-sectional questionnaire survey. Main outcome measurements Performance, organ distribution, severe adverse events of ESD-ITT. Results Feedback was received from 113 centers (84%), i.e. 73 (54%) ESD centers and 40 centers (30%) with zero ESD; 10 (7%) had published ESD; no feedback from 12 (9%) centers with unknown status. Altogether, 83 centers (61.5%) perform ESD: 21 (16%) had >150 ESD (professional category), 33 (24%) had 31-150 ESD (competent category), and 29 (21.5%) had ≤ 30 ESD (initial learning category). Most implemented ESD centers (91%, 72 of 79) were analyzed: Centers on initial learning (420 ESD) compared to centers with >30 ESD (5676 ESD) performed en-bloc ESD in 64% vs. 84%, hybrid-ESD in 26% vs.11% and piecemeal-EMR in 10% vs. 5.2%. Majority of ESD (66-68%) were in colorectum, overall with low risk (30-day mortality 0.03%, surgical repair 3.5% vs. 1.7%) and satisfactory outcome (oncosurgery 7.4% vs. 5.2%, local recurrence 1.5% vs. 0.3%). Conclusions Beyond guideline recommendations, unsupervised implementation of ESD was successful in colorectum with step-up approach. Now, Western ESD centers have to aim for professional (i.e. >80%) curative ESD