Block-Diagonalization and f-electron Effects in Tight-Binding Theory

We extend a tight-binding total energy method to include f-electrons, and apply it to the study of the structural and elastic properties of a range of elements from Be to U. We find that the tight-binding parameters are as accurate and transferable for f-electron systems as they are for d-electron systems. In both cases we have found it essential to take great care in constraining the fitting procedure by using a block-diagonalization procedure, which we describe in detail.Comment: 9 pages, 6 figure

The antenna sub-system for meteosat second generation satellites

The Meteosat Second Generation project (MSG) concerns a launch and operation of three new satellites in the coming years. MSG continues meteorological services, which are currently provided by the very successful first generation of satellites in the Meteosat Operational Program (MOP), operated by Eumetsat. MSG expands on the services offered by MOP by providing more frequently data in more observation bands, with higher resolution. The telecommunication system for the MSG satellite transmits the measured data to the primary ground station and receives and re-transmits pre-processed images and meteorological data from the latter station. It collects meteorological data from data collection platforms. The MSG satellite carries also a Search and Rescue transponder. The antenna sub-system has been specifically designed for the necessary functions and permits appropriate data throughput with the satellite spinning at a rate of 100 revolutions per minute. The antenna sub-system for MSG is explained, after a short general description

Herbal bathing : An analysis of variation in plant use among Saramaccan and Aucan Maroons in Suriname

Background: Herbal baths play an important role in the traditional health care of Maroons living in the interior of Suriname. However, little is known on the differences in plant ingredients used among and within the Maroon groups. We compared plant use in herbal baths documented for Saramaccan and Aucan Maroons, to see whether similarity in species was related to bath type, ethnic group, or geographical location. We hypothesized that because of their dissimilar cultural background, they used different species for the same type of bath. We assumed, however, that plants used in genital baths were more similar, as certain plant ingredients (e.g., essential oils), are preferred in these baths. Methods: We compiled a database from published and unpublished sources on herbal bath ingredients and constructed a presence/absence matrix per bath type and study site. To assess similarity in plant use among and within Saramaccan and Aucan communities, we performed three Detrended Correspondence Analyses on species level and the Jaccard Similarity Index to quantify similarity in bath ingredients. Results: We recorded 349 plants used in six commonly used bath types: baby strength, adult strength, skin diseases, respiratory ailments, genital steam baths, and spiritual issues. Our results showed a large variation in plant ingredients among the Saramaccan and Aucans and little similarity between Saramaccans and Aucans, even for the same type of baths. Plant ingredients for baby baths and genital baths shared more species than the others. Even within the Saramaccan community, plant ingredients were stronger associated with location than with bath type. Conclusions: Plant use in bathing was strongly influenced by study site and then by ethnicity, but less by bath type. As Maroons escaped from different plantations and developed their ethnomedicinal practices in isolation, there has been little exchange in ethnobotanical knowledge after the seventeenth century between ethnic groups. Care should be taken in extrapolating plant use data collected from one location to a whole ethnic community. Maroon plant use deserves more scientific attention, especially now as there are indications that traditional knowledge is disappearing

Large deployable antenna for various space applications

The article describes how an activity is going on for a design, development and realisation of a large 12 meter deployable reflector antenna for space applications. The reflector antenna system is subject of an ESA contract awarded to Alenia Spazio as a prime contractor. The Russian company NPO EGS is responsible as sub-contractor for an important element, which is the deployable reflector. Alenia has provided, together with ESA, instrumentation and testing expertises for assessment of Passive Intermodulation properties of the realised reflector, which is currently being prepared for environmental testing. Background knowledge was fed into the program from the Georgian antenna design, comparable to the one, which did fly on MIR station

A Tunable, Biodegradable, Thin-Film Polymer Device as a Long-Acting Implant Delivering Tenofovir Alafenamide Fumarate for HIV Pre-exposure Prophylaxis

PURPOSE: The effectiveness of Tenofovir based HIV pre-exposure prophylaxis (PrEP) is proven, but hinges on correct and consistent use. User compliance and therapeutic effectiveness can be improved by long acting drug delivery systems. Here we describe a thin-film polymer device (TFPD) as a biodegradable subcutaneous implant for PrEP. METHODS: A thin-film polycaprolactone (PCL) membrane controls drug release from a reservoir. To achieve membrane controlled release, TAF requires a formulation excipient such as PEG300 to increase the dissolution rate and reservoir solubility. Short-term In vitro release studies are used to develop an empirical design model, which is applied to the production of in vitro prototype devices demonstrating up to 90-days of linear release and TAF chemical stability. RESULTS: The size and shape of the TFPD are tunable, achieving release rates ranging from 0.5–4.4 mg/day in devices no larger than a contraceptive implant. Based on published data for oral TAF, subcutaneous constant-rate release for HIV PrEP is estimated at < 2.8mg/day. Prototype devices demonstrated linear release at 1.2mg/day for up to 90 days and at 2.2mg/day for up to 60 days. CONCLUSIONS: We present a biodegradable TFPD for subcutaneous delivery of TAF for HIV PrEP. The size, shape and release rate of the device are tunable over a > 8-fold range