Deployment requirements for deorbiting electrodynamic tether technology

In the last decades, green deorbiting technologies have begun to be investigated and have raised a great interest in the space community. Among the others, electrodynamic tethers appear to be a promising option. By interacting with the surrounding ionosphere, electrodynamic tethers generate a drag Lorentz force to decrease the orbit altitude of the satellite, causing its re-entry in the atmosphere without using propellant. In this work, the requirements that drive the design of the deployment mechanism proposed for the H2020 Project E.T.PACK\u2014Electrodynamic Tether Technology for Passive Consumable-less Deorbit Kit\u2014are presented and discussed. Additionally, this work presents the synthesis of the reference profiles used by the motor of the deployer to make the tethered system reach the desired final conditions. The result is a strategy for deploying electrodynamic tape-shaped tethers used for deorbiting satellites at the end of their operational life

Biomarkers in anal cancer: from biological understanding to stratified treatment

Squamous cell carcinomas of the anus and anal canal represent a model of a cancer and perhaps the first where level 1 evidence supported primary chemoradiotherapy (CRT) in treating locoregional disease with curative intent. The majority of tumours are associated with infection with oncogenic subtypes of human papilloma virus and this plays a significant role in their sensitivity to treatment. However, not all tumours are cured with CRT and there remain opportunities to improve outcomes in terms of oncological control and also reducing late toxicities. Understanding the biology of ASCC promises to allow a more personalised approach to treatment, with the development and validation of a range of biomarkers and associated techniques that are the focus of this review

The role of insulin in the action of the hypoglycemic sulfonyl compounds

In the preceding paper it was reported that hypoglycemic sulfonyl compounds did not produce a significant decrease in the blood sugar level in the absence of the pancreas (16 depancreatized dogs and 9 hypophysectomizeddepancreatized dogs).Fil: Houssay, Bernardo Alberto. Fundación de Instituto de Biología y Medicina Experimental; Argentina. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Fisiología; ArgentinaFil: Penhos, J. C.. Fundación de Instituto de Biología y Medicina Experimental; Argentina. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Fisiología; ArgentinaFil: Urgoiti, E.. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Fisiología; Argentina. Fundación de Instituto de Biología y Medicina Experimental; ArgentinaFil: Teodosio, N.. Fundación de Instituto de Biología y Medicina Experimental; Argentina. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Fisiología; ArgentinaFil: Apelbaum, J.. Fundación de Instituto de Biología y Medicina Experimental; Argentina. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Fisiología; ArgentinaFil: Bowkett, J.. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Fisiología; Argentina. Fundación de Instituto de Biología y Medicina Experimental; Argentinafond

Medya'daki futbol söylemi üzerine bir inceleme

Futbol, insana ve insanlığa ait değerleri bünyesinde barındırdığı ve dünyanın en kitlesel spor dalı olduğu için, her daim üzerinde konuşulmayı, araştırılmayı ve yorumlanmayı hak etmektedir. Futbol, toplumsal yaşam içerisinde bir ʻminyatürʼ model olarak işlev görmekte ve onun üzerinden toplumsal yaşama bir takım rol ve değer transferleri gerçekleştirilmektedir. Futbol var olan güç ve iktidar ilişkilerinin sürdürülmesine katkıda bulunmakla kalmamakta aynı zamanda toplumsal kontrolü sağlamada da bir araç rolünü üstlenmektedir. İdeoloji, futbolun içinde oturduğu maddi zemini teşkil ederken, futbol da ideolojinin, toplumsal yaşam içerisinde ortak duyu olarak kabulünde aracı olmaktadır. Futbol, üzerinde her kesimin konuşabildiği, yorum yapabildiği bir iktidar alanı yaratmakta ve bu iktidar alanı, gündelik hayatımız içerisinde var olan diğer iktidarlarla ve en tepedeki iktidar mekanizması ile örtüşmektedir. Bu örtüşmeyi, futbolun evrensel ve kitlesel bir referans alanı olabilmesi sağlamaktadır. Yaratılan futbol iktidarı özellikle medya dolayımı ile dolaşıma sokulmaktadır. Türkiyeʼde medya, futbolun sosyal yapı ile kurmuş olduğu değerlerin transferinde önemli bir rol oynamaktadır. 1980 sonrasında Türkiyeʼde ekonomik ve siyasal alanda yaşanan değişimlerin toplumsal yaşama aktarılmasında futboldan da yararlanılmıştır. Türkiyeʼde futbola yönelik alınan her türlü karar bir anlamda içinde yaşanılan toplumsal yaşamın ortaya çıkarttığı sorunlar ve bu sorunların taşındığı mekanların yeniden düzenlenmesi ile de ilintilidir. Futbol,varolan ideolojinin ve sınıfsal değerlerin korunması için sık sık müdahalelerde bulunulan bir alan haline dönüşmüştür. Türkiyeʼde futbol, politik-ekonomik ve medyatik meşrulaştırma aracı olarak kullanılmıştır/kullanılmaktadır. Aynı zamanda futbol yeni tüketim kalıplarının yerleştirilmesinde de kullanılmaktadır. Ayrıca futbolun toplumsal yaşama aktarılan değerlerin taşınmasında ve erkek egemen zihniyet kalıplarının üretilmesinde ve dolaşıma sokulmasında da büyük etkisi bulunmaktadır. Futbolu artık sadece bir oyun olarak düşünemeyiz, futbol aynı zamanda bir işʼtir ve büyük bir kitlesel fenomendir. Bu fenomeni kendi lehine kullanmak isteyen çeşitli gruplar her dönem olmuştur ve olmaya da devam edecektir

The E.T.PACK project: Towards a fully passive and consumable-less deorbit kit based on low-work-function tether technology

The Electrodynamic Tether Technology for Passive Consumable-less Deorbit Kit (E.T.PACK) is a project aimed at the development of a deorbit kit based on low-work-function Tether (LWT) technology, i.e., a fully passive and electrically floating system made of a long conductive tape coated with a low-work-function material. The LWT interacts passively with the environment (ambient plasma, magnetic field, and solar radiation) to exchange momentum with the planet's magnetosphere, thus enabling the spacecraft to de-orbit and/or re-boost without the need for consumables. The main goal is to develop a deorbit kit and related software with Technology Readiness Level 4 and promote a follow-up project to carry out an in-orbit experiment. The planned kit in the experiment has three modes of operation: fully passive LWT and conventional electrodynamic tether equipped with an active electron emitter in passive and active modes. Several activities of the project pivot around the C12A7:e 12 electride, which will be used in four hardware elements: (i) LWT (ii) hollow cathode, (iii) photo-enhanced thermionic emission device to convert solar photon energy into electrical energy, and (iv) a hollow cathode thruster. These elements, some of which do not belong to the deorbit kit, are synergetic with the main stream of the project and common to some tether applications like in-orbit propulsion and energy generation. This work explains the activities of E.T.PACK and the approach for solving its technological challenges. After reviewing past progresses on electrodynamic tethers and thermionic materials, we present a preliminary concept of the kit for the in-orbit experiment, some simulation results, and the key hardware elements

Low Work-Function Tether Deorbit Kit

This work presents a system level analysis of a Deorbit Kit (DK) based on electrodynamic tether technology. The analysis is focused on two relevant scenarios for deorbiting space debris: (i) Earth Observation (EO) satellites with mass in the range of 700kg -1000kg and initial orbital altitude of 800km and 98\uba inclination, and (ii) Mega Constellation (MC) spacecraft in the order of 200kg and initial orbit at 1200 km of altitude and 90\uba of inclination. The scenarios have been selected considering the orbits that are already suffering from the space debris problem or will suffer in the next future. The DK implements a bare electrodynamic tether for capturing electrons passively from the ambient plasma while different methods are used for emitting the electrons back to the plasma to reach a steady electrical current on the tether. The three studied options to close the electrical circuit are: (a) a hollow cathode, which has a high maturity but needs expellant and a little of power, (b) a thermionic emitter, which does not involve expellant but needs power, and (c) a Low Work-function Tether (LWT) that does not need neither expellant nor power because it has a segment coated with a special material that emits electrons passively through the thermionic and photoelectric effects. In order to provide a fully autonomous operation even in case of critical failure of the mother spacecraft, the DK includes a deployment mechanism, a telemetry and telecommand system, a complete Attitude Determination and Control System with attitude sensors (GNSS, sun sensors, magnetometer) and actuators (magneto torquers), solar panels and batteries. Upon activation, the DK autonomously de-tumbles the satellite, deploys a tether and carries out the satellite\u2019s de-orbiting. The study presents DK architectures, mass budgets and simulation results for the two scenarios. It is shown that complete DK with mass below 6% the mass of the host spacecraft can complete the deorbit maneuver of EO satellites in about 1.5 years and 10 years for MC satellites. The importance of the development of the LWT concept to enhance the simplicity and reduce the mass, power and volume budget is highlighted

The woodchuck interferon-alpha system: Cloning, family description, and biologic activity

Interferon-alpha (IFN-alpha) is a key element in the defense against viral infection because, in addition to a direct antiviral effect, it exhibits potent immunostimulatory activity. To investigate the function of this cytokine in the woodchuck model of chronic hepatitis B, the woodchuck IFN-alpha gene (IFNA) family was cloned and examined. The data indicate that this is a multigenic family from which 12 IFNA functional sequences and four pseudogene sequences were isolated. The overall identity of the amino acid sequence among the members of the woodchuck IFN-alpha family is 85%, and the identity with the IFN-alpha family from other species such as mice and humans is 50%. The analysis of hepatic expression of IFNA genes showed that wIFNA5a was the subtype transcribed preferentially in the woodchuck liver. The wIFNA genes transcribed in the liver were tested in an eukaryotic expression system and were found to enhance 2-5-oligoadenylate synthetase (2-5-OAS) mRNA levels and to posses a potent antiviral activity. Cloning of woodchuck IFNA genes will allow testing diverse forms of IFN-alpha delivery as well as different combination therapies in woodchuck hepatitis virus infection, thus providing useful information for the design of new strategies for the treatment of patients with chronic hepatitis B