Twins and their boundaries during homoepitaxy on Ir(111)

The growth and annealing behavior of strongly twinned homoepitaxial films on Ir(111) has been investigated by scanning tunneling microscopy, low energy electron diffraction and surface X-ray diffraction. In situ surface X-ray diffraction during and after film growth turned out to be an efficient tool for the determination of twin fractions in multilayer films and to uncover the nature of side twin boundaries. The annealing of the twin structures is shown to take place in a two step process, reducing first the length of the boundaries between differently stacked areas and only then the twins themselves. A model for the structure of the side twin boundaries is proposed which is consistent with both the scanning tunneling microscopy and surface X-ray diffraction data.Comment: 13 pages, 11 figure

Analysis of parainfluenza virus-5 hemagglutinin-neuraminidase protein mutants that are blocked in internalization and degradation

AbstractThe PIV-5 hemagglutinin-neuraminidase (HN) protein is a multifunctional protein with sialic acid binding, neuraminidase and fusion promotion activity. HN is internalized by clathrin-mediated endocytosis and degraded. HN lacks internalization signals in its cytoplasmic tail but a single glutamic acid present at residue 37 at the putative transmembrane/ectodomain boundary is critical. We rescued rPIV-5 with mutations E37D or E37K, which have been shown to impair or abolish HN internalization, respectively. These viruses exhibited growth properties similar to wild-type (wt) virus but are impaired for fitness in tissue culture. Biochemical analysis of HN activities showed differences between HN E37D and HN E37K in fusion promotion and incorporation of HN and F into virions. Furthermore, oligomeric analyses indicate that HN E37 mutants perturb the tetrameric organization of HN, probably by destabilizing the dimer-of-dimers interface

Perencanaan Dinding Geser Pada Struktur Gedung Beton Bertulang Dengan Sistem Ganda

Dinding geser pada Sistem Ganda sebagai salah satu alternatif sistem struktur, disyaratkan untuk memikul sebagian besar beban lateral, yaitu maksimum sebesar 75%. Distribusi beban lateral pada struktur dengan Sistem Ganda adalah proporsional sesuai dengan kekakuan relatif masing-masing komponennya. Selanjutnya, dengan beban yang sudah terdistribusi, dilakukan perencanaan pada dinding geser. Dengan menetapkan kekakuan relatif dinding geser terhadap seluruh gedung, akan didapatkan dimensi dinding geser yang diperlukan untuk memenuhi kekakuan rencana. Selanjutnya, dilakukan perhitungan massa gedung dan didapatkan gaya gempa berupa gaya geser dasar nominal V. Dengan Analisis Statik Ekuivalen didapatkan gaya geser dasar horizontal Fi untuk tiap lantainya. Gaya geser Fi kemudian didistribusikan ke tiap portal yang proporsinya sesuai dengan kekakuan relatifnya, sesuai dengan syarat Sistem Ganda. Dengan memodelkan dinding geser sebagai struktur kantilever, didapatkan gaya geser dan momen lentur, dan dari analisis terhadap tributary area (area yang didukung oleh dinding geser), didapatkan gaya aksial yang bekerja pada penampang dinding geser. Dari gaya-gaya dalam hasil analisis tersebut, direncanakan tulangan tulangan horizontal dan vertikal. Kemudian dari tulangan vertikal yang terpasang, dilakukan pemeriksaan kapasitas penampang terhadap lentur dan aksial dengan bantuan diagram interaksi

Drug Use on Mont Blanc: A Study Using Automated Urine Collection

Mont Blanc, the summit of Western Europe, is a popular but demanding high-altitude ascent. Drug use is thought to be widespread among climbers attempting this summit, not only to prevent altitude illnesses, but also to boost physical and/or psychological capacities. This practice may be unsafe in this remote alpine environment. However, robust data on medication during the ascent of Mont Blanc are lacking. Individual urine samples from male climbers using urinals in mountain refuges on access routes to Mont Blanc (Goûter and Cosmiques mountain huts) were blindly and anonymously collected using a hidden automatic sampler. Urine samples were screened for a wide range of drugs, including diuretics, glucocorticoids, stimulants, hypnotics and phosphodiesterase 5 (PDE-5) inhibitors. Out of 430 samples analyzed from both huts, 35.8% contained at least one drug. Diuretics (22.7%) and hypnotics (12.9%) were the most frequently detected drugs, while glucocorticoids (3.5%) and stimulants (3.1%) were less commonly detected. None of the samples contained PDE-5 inhibitors. Two substances were predominant: the diuretic acetazolamide (20.6%) and the hypnotic zolpidem (8.4%). Thirty three samples were found positive for at least two substances, the most frequent combination being acetazolamide and a hypnotic (2.1%). Based on a novel sampling technique, we demonstrate that about one third of the urine samples collected from a random sample of male climbers contained one or several drugs, suggesting frequent drug use amongst climbers ascending Mont Blanc. Our data suggest that medication primarily aims at mitigating the symptoms of altitude illnesses, rather than enhancing performance. In this hazardous environment, the relatively high prevalence of hypnotics must be highlighted, since these molecules may alter vigilance

Operation Everest III: energy and water balance

We hypothesized that hypoxia decreases energy intake and increases total energy requirement and, additionally, that decreased barometric pressure increases total water requirement. Energy and water balance was studied over 31 days in a hypobaric chamber at 452-253 Torr (corresponding to 4,500-8,848 m altitude), after 7 days acclimatization at 4,350 m. Subjects were eight men, age 27+/-4 years (mean+/-SD), body mass index 22.9+/-1.5 kg/m(2). Food and water intake was measured with weighed dietary records, energy expenditure and water loss with labelled water. Insensible water loss was calculated as total water loss minus urinary and faecal water loss. Energy intake at normoxia was 13.6+/-1.8 MJ/d. Energy intake decreased from 10.4+/-2.1 to 8.3+/-1.9 MJ/d (

In situ GISAXS study of the growth of Pd on MgO(001)

The morphology of growing Pd nano-particles on MgO(001) surfaces have been investigated in situ, during growth, by grazing incidence small angle x-ray scattering, for different substrate temperatures. The 2D patterns obtained are quantitatively analyzed, and the average morphological parameters (shape, size) deduced. Above 650 K, the aggregates adopt their equilibrium shape of truncated octahedron, and the interfacial energy is deduced.Comment: 10 pages, 1 Table, 2 Figure

A DfT Architecture for Asynchronous Networks-on-Chip

International audienceThe Networks-on-Chip (NoCs) paradigm is emerging as a solution for the communication of SoCs. Many NoC architecture propositions are presented but few works on testing these network architectures. To test the SoCs, the main challenge is to reach into the embedded cores (i.e, the IPs). In this case, the DFT techniques that integrate test architectures into the SoCs to ease the test of these SoCs are really favoured. In this paper, we present a new methodology for testing NoC architectures. A modular, generic, scalable and configurable DFT architecture is developed in order to ease the test of NoC architectures. The target of this test architecture is asynchronous NoC architectures that are implemented in GALS systems. The proposed architecture is therefore named ANOC-TEST and is implemented in QDI asynchronous circuits. In addition, this architecture can be used to test the computing resources of the networked SoCs. Some initial results and conclusions are also give

How to Implement an Asynchronous Test Wrapper for Network-on-Chip Nodes

International audienceThe Network-on-Chip (NoC) paradigm is currently known as an alternative solution for the on chip communication in the next SoC generation, especially, asynchronous NoCs. One of the challenges for asynchronous NoC-based systems design is testing asynchronous network architectures for manufacturing defects. To improve the testability of asynchronous NoCs, we have developed a scalable and configurable asynchronous Design-for-Test (DfT) architecture. In this architecture, each asynchronous network node is surrounded by an asynchronous test wrapper and the network communication channels are reused as a high-speed Test Access Mechanism (TAM). This architecture is designed to test all network elements (routers, communication channels), but it can also be used to test computational resources. In this paper, we introduce how to realize and implement the test wrapper in Quasi Delay Insensitive (QDI) asynchronous logic style. The validation and experimental results are also presented