Oxidative stress stimulates alpha-tocopherol transfer protein in human trophoblast tumor cells BeWo

alpha-Tocopherol transfer protein (alpha-TTP) has been identified as the major intracellular transport protein for the antioxidant vitamin E (alpha-Tocopherol). Expression of alpha-TTP on the reproductive system has been described both in mouse uterus and lately in the human placenta. The aim of this study was to clarify if placental expression of alpha-TTP can be modified by substances causing oxidative reactions. The human choriocarcinoma cell line BeWo was, therefore, treated with two known pro-oxidants. alpha-TTP expression was determined with immunocytochemistry and evaluated by applying a semiquantitative score. The presence of pro-oxidants in BeWo cells induced alpha-TTP expression. We thus hypothesize that stimulation of alpha-TTP expression by oxidative stress, as this was induced by pro-oxidants, could be part of an antioxidant process occurring in the placenta in the aim of enhancing the supply of alpha-Tocopherol. This process could occur both in normal pregnancies, as well as in pregnancy disorders presented with intensified oxidative stress. In that view, this model is proposed for further oxidative stress studies on trophoblast and placenta, on the grounds of clarifying the role of alpha-Tocopherol in pregnancy physiology and pathophysiology

Gas-Phase Reaction Kinetics of the Ortho and Ipso Adducts 1,2,4,5-Tetramethylbenzene-OH with O-2

The reversible reaction of OH radicals with 1,2,4,5-tetramethylbenzene (1245-TeMB, durene) leads to adducts at the substituted (ipso) and unsubstituted (ortho) positions of the ring. By the use of flash photolysis for production and resonance fluorescence for detection of OH, the gas-phase reactions of O-2 with these adducts were investigated over the temperature range of 300-340 K in He at 200 mbar. The decay of OH, generated by pulsed vacuum-UV photolysis of H2O, was monitored under slow-flow conditions in the presence of 1245-TeMB and O-2 at concentrations of up to 19 X 10(12) CM-3 and 2 X 10(16) cm(-3), respectively. Triexponential OH decays resulted from the unimolecular decomposition of the two adducts, representing OH reservoirs with different stabilities. In the presence of O-2, additional adduct loss pathways exist, leading to faster OH consumption. Triexponential functions fitted to these decays were analyzed to obtain rate constants for the reactions of O-2 with both adducts. Rate constants in the range of (4-13) x 10(-15) and (0.3-3) x 10(-15) cm(3)s(-1) were obtained for the ortho and the ipso adducts, respectively, depending on temperature and assumptions regarding details of the underlying mechanism of adduct isomer formation and isomerization. At O-2 concentrations exceeding about 1 x 10(16) cm(-3), deviations from a linear dependence of the adduct loss rates on the O-2 concentration indicate an even more complex mechanism. The validity of the rate constants is therefore confined to O-2 concentrations below 1 X 10(16) cm(-3). The adduct + O-2 rate constants for 1245-TeMB are greater than the corresponding previously obtained rate constants for benzene, toluene, and p- and m-xylene but smaller than those for hexamethylbenzene. The results are discussed in terms of the current knowledge about the mechanism of OH-induced degradation of aromatic compounds in the presence of O-2

Competition between water uptake and ice nucleation by glassy organic aerosol particles

Berkemeier T, Shiraiwa M, Poeschl U, Koop T. Competition between water uptake and ice nucleation by glassy organic aerosol particles. Atmospheric Chemistry and Physics. 2014;14(22):12513-12531.Organic aerosol particles play a key role in climate by serving as nuclei for clouds and precipitation. Their sources and composition are highly variable, and their phase state ranges from liquid to solid under atmospheric conditions, affecting the pathway of activation to cloud droplets and ice crystals. Due to slow diffusion of water in the particle phase, organic particles may deviate in phase and morphology from their thermodynamic equilibrium state, hampering the prediction of their influence on cloud formation. We overcome this problem by combining a novel semi-empirical method for estimation of water diffusivity with a kinetic flux model that explicitly treats water diffusion. We estimate timescales for particle deliquescence as well as various ice nucleation pathways for a wide variety of organic substances, including secondary organic aerosol (SOA) from the oxidation of isoprene, alpha-pinene, naphthalene, and dodecane. The simulations show that, in typical atmospheric updrafts, glassy states and solid/liquid core-shell morphologies can persist for long enough that heterogeneous ice nucleation in the deposition and immersion mode can dominate over homogeneous ice nucleation. Such competition depends strongly on ambient temperature and relative humidity as well as humidification rate and particle size. Due to differences in glass transition temperature, hygroscopicity and atomic O/C ratio of the different SOA, naphthalene SOA particles have the highest potential to act as heterogeneous ice nuclei. Our findings demonstrate that kinetic limitations of water diffusion into organic aerosol particles are likely to be encountered under atmospheric conditions and can strongly affect ice nucleation pathways. For the incorporation of ice nucleation by organic aerosol particles into atmospheric models, our results demonstrate a demand for model formalisms that account for the effects of molecular diffusion and not only describe ice nucleation onsets as a function of temperature and relative humidity but also include updraft velocity, particle size and composition

Retreat into scientism, paradoxes of transparency, and corruption in education

Um dos sintomas da razão indolente (SANTOS, 2006) é o recuo ao cientificismo, o qual tem sido, particularmente, acentuado nas políticas, cada vez mais hegemônicas, de avaliação, de prestação de contas e de responsabilização. Por isso, um dos objetivos deste texto é o de colocar em causa este aparente consenso cientificista (ou este consenso supostamente transideológico) e fazer uma breve incursão exploratória ao que aqui se designa de paradoxos da transparência. Considera-se que esses paradoxos traduzem a existência de tensões e contradições relativas a uma dimensão central dos discursos políticos e educacionais contemporâneos. Com isso, o artigo pretende dar continuidade a uma linha de pesquisa que tem procurado sublinhar a relevância da necessidade de complexificar e dar maior rigor teórico-conceptual à accountability em educação. Finalmente, tentando abrir caminho para o desenvolvimento de novas articulações e análises, chama-se a atenção para a corrupção na educação cuja complexidade ainda é insuficientemente conhecida e pesquisada, nomeadamente, nas suas relações com as problemáticas da transparência e da accountability. Admite-se que as práticas de corrupção em educação, em muitas situações, são (paradoxalmente) induzidas pela necessidade de dar resposta à governação baseada nos números, nos rankings e nas (supostas) evidências, anulando completamente as expectativas legítimas em torno da transparência dos processos educacionais e das decisões políticas.One symptom of “indolent reason” (SANTOS, 2006) is the retreat into scientism, which is especially marked in the increasingly hegemonic policies surrounding assessment, reporting and accountability. As such, one of the aims of this paper is to call into question this apparent consensus on scientism (a supposedly trans-ideological consensus), and briefly explore what we define as the paradoxes of transparency. These paradoxes are found to reveal the existence of tensions and contradictions concerning a central aspect of current political and educational discourse. In doing so, the article seeks to continue a line of study which has aimed to emphasize the significance of the need for a more complex, and theoretically and conceptually rigorous understanding of accountability in education. Finally, in an attempt to pave the way for further discussion and analysis, attention is drawn to corruption in education, the complex nature of which remains insufficiently understood and studied, notably in terms of its relationship with the problems of transparency and accountability. It is acknowledged that practices of corruption within education are, in many situations, (paradoxically) caused by the need to answer to a system of governance based on numbers, league tables, and (supposed) truths, completely nullifying legitimate expectations about the transparency of educational processes and policy decisions.Trabalho financiado por Fundos Nacionais através da FCT – Fundação para a Ciência e a Tecnologia – no âmbito do Projeto PEst-OE/CED/UI1661/2014.info:eu-repo/semantics/publishedVersio

Research and Design of a Routing Protocol in Large-Scale Wireless Sensor Networks

无线传感器网络，作为全球未来十大技术之一，集成了传感器技术、嵌入式计算技术、分布式信息处理和自组织网技术，可实时感知、采集、处理、传输网络分布区域内的各种信息数据，在军事国防、生物医疗、环境监测、抢险救灾、防恐反恐、危险区域远程控制等领域具有十分广阔的应用前景。 本文研究分析了无线传感器网络的已有路由协议，并针对大规模的无线传感器网络设计了一种树状路由协议，它根据节点地址信息来形成路由，从而简化了复杂繁冗的路由表查找和维护，节省了不必要的开销，提高了路由效率，实现了快速有效的数据传输。 为支持此路由协议本文提出了一种自适应动态地址分配算——ADAR（AdaptiveDynamicAddre...As one of the ten high technologies in the future, wireless sensor network, which is the integration of micro-sensors, embedded computing, modern network and Ad Hoc technologies, can apperceive, collect, process and transmit various information data within the region. It can be used in military defense, biomedical, environmental monitoring, disaster relief, counter-terrorism, remote control of haz...学位：工学硕士院系专业：信息科学与技术学院通信工程系_通信与信息系统学号：2332007115216

Amorphous and crystalline aerosol particles interacting with water vapor: conceptual framework and experimental evidence for restructuring, phase transitions and kinetic limitations

Mikhailov E, Vlasenko S, Martin ST, Koop T, Poeschl U. Amorphous and crystalline aerosol particles interacting with water vapor: conceptual framework and experimental evidence for restructuring, phase transitions and kinetic limitations. ATMOSPHERIC CHEMISTRY AND PHYSICS. 2009;9(24):9491-9522.Interactions with water are crucial for the properties, transformation and climate effects of atmospheric aerosols. Here we present a conceptual framework for the interaction of amorphous aerosol particles with water vapor, outlining characteristic features and differences in comparison to crystalline particles. We used a hygroscopicity tandem differential mobility analyzer (H-TDMA) to characterize the hydration and dehydration of crystalline ammonium sulfate, amorphous oxalic acid and amorphous levoglucosan particles (diameter ~100 nm, relative humidity 5–95% at 298 K). The experimental data and accompanying Köhler model calculations provide new insights into particle microstructure, surface adsorption, bulk absorption, phase transitions and hygroscopic growth. The results of these and related investigations lead to the following conclusions: (1) Many organic substances, including carboxylic acids, carbohydrates and proteins, tend to form amorphous rather than crystalline phases upon drying of aqueous solution droplets. Depending on viscosity and microstructure, the amorphous phases can be classified as glasses, rubbers, gels or viscous liquids. (2) Amorphous organic substances tend to absorb water vapor and undergo gradual deliquescence and hygroscopic growth at lower relative humidity than their crystalline counterparts. (3) In the course of hydration and dehydration, certain organic substances can form rubber- or gel-like structures (supramolecular networks) and undergo transitions between swollen and collapsed network structures. (4) Organic gels or (semi-)solid amorphous shells (glassy, rubbery, ultra-viscous) with low molecular diffusivity can kinetically limit the uptake and release of water and may influence the hygroscopic growth and activation of aerosol particles as cloud condensation nuclei (CCN) and ice nuclei (IN). Moreover, (semi-)solid amorphous phases may influence the uptake of gaseous photo-oxidants and the chemical transformation and aging of atmospheric aerosols. (5) The shape and porosity of amorphous and crystalline particles formed upon dehydration of aqueous solution droplets depend on chemical composition and drying conditions. The apparent volume void fractions of particles with highly porous structures can range up to ~50% or more (xerogels, aerogels). (6) For efficient description of water uptake and phase transitions of aerosol particles, we propose not to limit the terms deliquescence and efflorescence to equilibrium phase transitions of crystalline substances. Instead we propose generalized definitions according to which amorphous and crystalline components can undergo gradual or prompt, partial or full deliquescence or efflorescence. We suggest that (semi-)solid amorphous phases may be important not only in the upper atmosphere as suggested in recent studies of glass formation at low temperatures. Depending on relative humidity, (semi-)solid phases and moisture-induced glass transitions may also play a role in gas-particle interactions at ambient temperatures in the lower atmosphere

Strategic Process Planning for Commissioning Processes in Mechanical Engineering

Planning in mechanical engineering is a key factor for a successful product development process. Especially, when it comes to producing machines, planning drastically reduces the risk of failures in either processes or parts. The commissioning process is mainly focusing on adjusting and testing. Thus, commissioning is the process where most of the failures are detected. On the one hand, in literature, the planning of processes has mainly focused on the optimisation of the planned duration of a production process. Durations of errors in processes and possible effects on other processes have not been considered in the literature. On the other hand, risk analyses mainly focus on the minimisation of errors in either processes or products. The goal of this paper is to develop an applicable methodology for the combination of an optimisation of the risk and the duration of a commissioning process in mechanical engineering. The focus is to analyse the planning of a commissioning process and combine it with a methodology to optimise risks and durations. Furthermore, the method is designed to be applicable in all areas of mechanical engineering. The method is validated at the commissioning of special machinery and during ramp-up processes and has shown a possible time reduction of about 40% without increasing the risks of failures

Expert Systems in Special Machinery: Increasing the Productivity of Processes in Commissioning

Due to the megatrend globalization, special machinery is gaining significance for the capital goods sector. Characterized by the fulfillment of individual customer requirements, companies in special machinery have to deal with very specific and technologically complex tasks. Hence, managing information and knowledge becomes vital for a company’s competitive ability, notably when it comes to expert knowledge. The characteristics of special machines leads to iterative processes for problem solving and thereby, increase lead times significantly. The more technologically complex a machine is, the more scattered the expert knowledge, meaning that many different experts need to be consulted before solving a problem. Up to now, in scientific literature, there has been little discussion about the challenges of special machinery and practical solutions regarding an implementation of technical intelligence in a special machinery environment. Therefore, the goal of this paper is to give an example of how an expert system can be applied to special machinery surroundings and thus, increases productivity. A Bayesian network forms the basis of the system as it allows efficient inference algorithms and reasoning under uncertainty, despite its ability to describe complex dependencies. The expert systems capability has been proven in industrial laser manufacturing

Gas uptake and chemical aging of semisolid organic aerosol particles

Shiraiwa M, Ammann M, Koop T, Poeschl U. Gas uptake and chemical aging of semisolid organic aerosol particles. PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES. 2011;108(27):11003-11008.Organic substances can adopt an amorphous solid or semisolid state, influencing the rate of heterogeneous reactions and multiphase processes in atmospheric aerosols. Here we demonstrate how molecular diffusion in the condensed phase affects the gas uptake and chemical transformation of semisolid organic particles. Flow tube experiments show that the ozone uptake and oxidative aging of amorphous protein is kinetically limited by bulk diffusion. The reactive gas uptake exhibits a pronounced increase with relative humidity, which can be explained by a decrease of viscosity and increase of diffusivity due to hygroscopic water uptake transforming the amorphous organic matrix from a glassy to a semisolid state (moisture-induced phase transition). The reaction rate depends on the condensed phase diffusion coefficients of both the oxidant and the organic reactant molecules, which can be described by a kinetic multilayer flux model but not by the traditional resistor model approach of multiphase chemistry. The chemical lifetime of reactive compounds in atmospheric particles can increase from seconds to days as the rate of diffusion in semisolid phases can decrease by multiple orders of magnitude in response to low temperature or low relative humidity. The findings demonstrate that the occurrence and properties of amorphous semisolid phases challenge traditional views and require advanced formalisms for the description of organic particle formation and transformation in atmospheric models of aerosol effects on air quality, public health, and climate