Two-dimensional tetramer-cuprate Na5RbCu4(AsO4)4Cl2: phase transitions and AFMorder as seen by 87Rb NMR

We report the Rb nuclear magnetic resonance (NMR) results in a recently synthesized Na5RbCu4(AsO4)Cl2. This complex novel two-dimensional (2D) cuprate is an unique magnetic material, which contains layers of coupled Cu4O4 tetramers. In zero applied magnetic field, it orders antiferromagnetically via a second-order low-entropy phase transition at TN = 15(1) K. We characterise the ordered state by 87Rb NMR, and suggest for it a noncollinear rather than collinear arrangement of spins. We discuss the properties of Rb nuclear site and point out the new structural phase transition(s) around 74 K and 110 K.Comment: 2 pages, 2 figures, Proceedings of SCES'05, Vienna 200

Envelopes of open sets and extending holomorphic functions on dual Banach spaces

We investigate certain envelopes of open sets in dual Banach spaces which are related to extending holomorphic functions. We give a variety of examples of absolutely convex sets showing that the extension is in many cases not possible. We also establish connections to the study of iterated weak* sequential closures of convex sets in the dual of separable spaces.Comment: 20 page

Space Shuttle Communications Coverage Analysis for Thermal Tile Inspection

The space shuttle ultra-high frequency Space-to-Space Communication System has to provide adequate communication coverage for astronauts who are performing thermal tile inspection and repair on the underside of the space shuttle orbiter (SSO). Careful planning and quantitative assessment are necessary to ensure successful system operations and mission safety in this work environment. This study assesses communication systems performance for astronauts who are working in the underside, non-line-of-sight shadow region on the space shuttle. All of the space shuttle and International Space Station (ISS) transmitting antennas are blocked by the SSO structure. To ensure communication coverage at planned inspection worksites, the signal strength and link margin between the SSO/ISS antennas and the extravehicular activity astronauts, whose line-of-sight is blocked by vehicle structure, was analyzed. Investigations were performed using rigorous computational electromagnetic modeling techniques. Signal strength was obtained by computing the reflected and diffracted fields along the signal propagation paths between transmitting and receiving antennas. Radio frequency (RF) coverage was determined for thermal tile inspection and repair missions using the results of this computation. Analysis results from this paper are important in formulating the limits on reliable communication range and RF coverage at planned underside inspection and repair worksites

Effects of high-field electrical stress on the conduction properties of ultra-thin La2O3 films

Electron transport in high-field stressed metal-insulator-silicon devices with ultrathin (<5nm) lanthanum oxide layers is investigated. We show that the leakage current flowing through the structure prior to degradation is direct and Fowler-Nordheimtunneling conduction, while that after stress exhibits diode-like behavior with series and parallel resistances. In this latter case, a closed-form expression for the current-voltage characteristic, based on the Lambert W function, is presented. Current evolution from one regime to the other during constant voltage stress takes place by means of discrete current steps of nearly identical magnitude, which would be indicative of the occurrence of multiple dielectric breakdowns across the insulating layer

Grammar Jam: Adding a Creative Editing Tactic

The author argues reading, hearing, and then composing musical lyrics involving grammatical concerns can help college writing students to edit more effectively for a song\u27s grammar topic. Explaining that the songs need to offer specific advice, such as how to both spot and correct the grammatical problem, the writer offers lyrical examples and provides scholarly evidence for this approach. The essay explains what Grammar Jam is, why music can work, and how to use the tactic in the classroom

Interfacial microstructure and shear strength of Ti-6Al-4V/TiAl laminate composite sheet fabricated by hot packed rolling

A two layer Ti-6Al-4V(wt%)/Ti-43Al-9V-Y(at%) laminate composite sheet with a uniform interfacial microstructure and no discernible defects at the interfaces has been prepared by hot-pack rolling, and its interfacial microstructure and shear strength were characterized. Characterization of the interfacial microstructure shows that there was an interfacial region of uniform thickness of about 250 μm which consisted of two layers: Layer I on the TiAl side which was 80 μm thick and Layer II on the Ti-6Al-4V side which was 170 μm thick. The microstructure of Layer I consisted of massive γ phases, needlelike γ phases and B2 phase matrix, while the microstructure of Layer II consisted of α₂ phase. The microstructure of the interfacial region is the result of the interdiffusion of Ti element from Ti-6Al-4V alloy layer into the TiAl alloy layer and Al element from the TiAl alloy layer into the Ti-6Al-4V alloy layer. The shear strength measurement demonstrated that the bonding strength between the TiAl alloy and Ti-6Al-4V alloy layers in the laminate composite sheet was very high. This means that the quality of the interfacial bonding between the two layers achieved by the multi-path rolling is high, and the interface between the layers is very effective in transferring loading, causing significantly improved toughness and plasticity of the TiAl/Ti-6Al-4V laminate composite sheet

Skuteczność jednostronnej adrenalektomii laparoskopowej w hiperkortyzolemii i subklinicznym zespole Cushinga niezależnych od ACTH — badanie retrospektywne na dużej kohorcie

Introduction: To assess the effectiveness of early unilateral laparoscopic adrenalectomy in ACTH-independent and subclinical hypercor­tisolaemia. Material and methods: We conducted a unicentric, retrospective study. Between 2010 and 2015, 356 laparoscopic adrenalectomies were performed in the Department of General and Endocrine Surgery of the MUW. Hypercortisolaemia was found in 50 (14%) patients, while overt hypercortisolaemia was found in 31 patients. In the hypercortisolaemia group, ACTH-dependent hypercortisolaemia was diagnosed in five (10%) and ACTH-independent hypercortisolaemia in 25 patients (50%). One patient with overt hypercortisolaemia had cancer of the adrenal cortex. The remaining 19 (38%) patients had subclinical Cushing’s syndrome. For our study, we compared patients with ACTH-independent hypercortisolaemia (n = 25) with those with Cushing’s syndrome (n = 19). Patients with ACTH-dependent hyper­cortisolaemia (n = 5) and the patient with cancer of the adrenal cortex (n = 1) were excluded. Results: Patients from both groups (n = 44) underwent a unilateral transperitoneal adrenalectomy. Good early outcomes were observed in 42 patients (93.3%). In one patient, an additional laparoscopic surgery was necessary on postoperative day 0 due to bleeding. In another patient, on day 22 post-surgery, we found an abscess in the site of the excised adrenal gland, which was drained under laparoscopic guid­ance. In three patients (6.8%) with substantial obesity, temporary respiratory insufficiency of varying degrees occurred. We did not observe any thromboembolic complications. All patients with overt hypercortisolaemia and nine patients with subclinical hypercortisolaemia had secondary adrenal insufficiency postoperatively. Conclusions: Transperitoneal unilateral laparoscopic adrenalectomy is an efficient and safe treatment option in patients with ACTH- -independent hypercortisolaemia, both overt and subclinical.Wstęp: Celem pracy była ocena skuteczności wczesnej jednostronnej adrenalektomii laparoskopowej w niezależnej od ACTH i subkli­nicznej hiperkortyzolemii. Materiał i metody: Przeprowadzono jednoośrodkowe, retrospektywne badanie. W latach 2010–2015 wykonano 356 adrenalektomii laparoskopowych w Klinice Chirurgii Ogólnej i Endokrynologicznej Warszawskiego Uniwersytetu Medycznego (WUM). Hiperkortyzo­lemię stwierdzono u 50 pacjentów (14%), natomiast jawną hiperkortyzolemię u 31 pacjentów. W grupie pacjentów z hiperkortyzolemią, hiperkortyzolemię ACTH-zależną zdiagnozowano u pięciu (10%) pacjentów, natomiast ACTH-niezależną u 25 (50%) pacjentów. U jednego z pacjentów z jawną hiperkortyzolemią stwierdzono raka kory nadnerczy. U pozostałych 19 (38%) pacjentów stwierdzono subkliniczny zespół Cushinga. Dla celów niniejszego badania, porównano pacjentów z ACTH-niezależną hiperkortyzolemią (n = 25) z pacjentami z zespołem Cushinga (n = 19). Z badania zostali wykluczeni pacjenci z ACTH-zależną hiperkortyzolemią (n = 5) oraz pacjent z rakiem kory nadnerczy (n = 1). Wyniki: Pacjentów z obu grup (n = 44) poddano jednostronnej adrenalektomii przezotrzewnowej. Dobre wczesne wyniki leczenia zaob­serwowano u 42 pacjentów (93,3%). U jednego z pacjentów konieczna była dodatkowa operacja laparoskopowa z powodu krwawienia w 0. dobie pooperacyjnej. U innego pacjenta, w 22. dobie pooperacyjnej, wykryto ropień w miejscu wyciętego gruczołu nadnerczowego, który został odsączony pod kontrolą laparoskopową. W przypadku trzech pacjentów (6,8%) ze znaczną otyłością, wystąpiła przejściowa niewydolność oddechowa o różnym stopniu nasilenia. Nie zaobserwowano żadnych powikłań zakrzepowo-zatorowych. U wszystkich pacjentów z jawną hiperkortyzolemią oraz u dziewięciu pacjentów z subkliniczną hiperkortyzolemią stwierdzono wtórną niewydolność nadnerczy po operacji. Wnioski: Jednostronna laparoskopowa adrenalektomia przezotrzewnowa jest skuteczną i bezpieczną opcją leczenia pacjentów z ACTH­-niezależną hiperkortyzolemią, zarówno jawną jak i subkliniczną