Detecção do peptídeo p17 (HIV) baseado em SERS (Surface-enhanced Raman Spectrosocpy)

Pós-graduação em Química - IQ

Review of Native Americans in the School System: Family, Community, and Academic Achievement by Carol J. Ward

The title of this volume promises more than the content delivers. The heart of the book is information from Ward's 1992 University of Chicago doctoral dissertation, which focused on the social and cultural reasons leading to students dropping out of school. Her first two chapters provide a good review of research on dropouts and Indian education; the following six focus on the results of her 1987-1989 study of 698 Northern Cheyenne, Crow, and white high school students attending the Colstrip Public, St. Labre Catholic, and Busby Tribal Schools in Montana. Fifty-two percent of the students in this study were Indian, with a dropout rate of 45% .

Microwave-assisted enzymatic synthesis of beef tallow biodiesel

Optimal conditions for the microwave-assisted enzymatic synthesis of biodiesel have been developed by a full 2(2) factorial design leading to a set of seven runs with different combinations of molar ratio and temperature. The main goal was to reduce the reaction time preliminarily established by a process of conventional heating. Reactions yielding biodiesel, in which beef tallow and ethanol used as raw materials were catalyzed by lipase from Burkholderia cepacia immobilized on silica-PVA and microwave irradiations within the range of 8-15 W were performed to reach the reaction temperature. Under optimized conditions (1:6 molar ratio of beef tallow to ethanol molar ratio at 50A degrees C) almost total conversion of the fatty acid presented in the original beef tallow was converted into ethyl esters in a reaction that required 8 h, i.e., a productivity of about 92 mg ethyl esters g(-1) h(-1). This represents an increase of sixfold for the process carried out under conventional heating. In general, the process promises low energy demand and higher biodiesel productivity. The microwave assistance speeds up the enzyme catalyzed reactions, decreases the destructive effects on the enzyme of the operational conditions such as, higher temperature, stability, and specificity to its substrate, and allows the entire reaction medium to be heated uniformly.

Towards a hybrid approach for adapting web graphical user interfaces to heterogeneous devices using context

Ubiquitous Computing promises seamless access to a wide range of applications and Internet based services from anywhere, at anytime, and using any device. In this scenario, new challenges for the practice of software development arise: Applications and services must keep a coherent behavior, a proper appearance, and must adapt to a plenty of contextual usage requirements and hardware aspects. Especially, due to its interactive nature, the interface content of Web applications must adapt to a large diversity of devices and contexts. In order to overcome such obstacles, this work introduces an innovative methodology for content adaptation of Web 2.0 interfaces. The basis of our work is to combine static adaption - the implementation of static Web interfaces; and dynamic adaptation - the alteration, during execution time, of static interfaces so as for adapting to different contexts of use. In hybrid fashion, our methodology benefits from the advantages of both adaptation strategies - static and dynamic. In this line, we designed and implemented UbiCon, a framework over which we tested our concepts through a case study and through a development experiment. Our results show that the hybrid methodology over UbiCon leads to broader and more accessible interfaces, and to faster and less costly software development. We believe that the UbiCon hybrid methodology can foster more efficient and accurate interface engineering in the industry and in the academy.

Electronic Structure Calculations in a 2D SixGe1-x Alloy Under an Applied Electric Field.

The recent advances and promises in nanoscience and nanotechnology have been focused on hexagonal materials, mainly on carbon-based nanostructures. Recently, new candidates have been raised, where the greatest efforts are devoted to a new hexagonal and buckled material made of silicon, named Silicene. This new material presents an energy gap due to spin-orbit interaction of approximately 1.5 meV, where the measurement of quantum spin Hall effect(QSHE) can be made experimentally. Some investigations also show that the QSHE in 2D low-buckled hexagonal structures of germanium is present. Since the similarities, and at the same time the differences, between Si and Ge, over the years, have motivated a lot of investigations in these materials. In this work we performed systematic investigations on the electronic structure and band topology in both ordered and disordered SixGe1-x alloys monolayer with 2D honeycomb geometry by first-principles calculations. We show that an applied electric field can tune the gap size for both alloys. However, as a function of electric field, the disordered alloy presents a W-shaped behavior, similarly to the pure Si or Ge, whereas for the ordered alloy a V-shaped behavior is observed.

Memory hierarchy and data communication in heterogeneous reconfigurable SoCs

The miniaturization race in the hardware industry aiming at continuous increasing of transistor density on a die does not bring respective application performance improvements any more. One of the most promising alternatives is to exploit a heterogeneous nature of common applications in hardware. Supported by reconfigurable computation, which has already proved its efficiency in accelerating data intensive applications, this concept promises a breakthrough in contemporary technology development. Memory organization in such heterogeneous reconfigurable architectures becomes very critical. Two primary aspects introduce a sophisticated trade-off. On the one hand, a memory subsystem should provide well organized distributed data structure and guarantee the required data bandwidth. On the other hand, it should hide the heterogeneous hardware structure from the end-user, in order to support feasible high-level programmability of the system. This thesis work explores the heterogeneous reconfigurable hardware architectures and presents possible solutions to cope the problem of memory organization and data structure. By the example of the MORPHEUS heterogeneous platform, the discussion follows the complete design cycle, starting from decision making and justification, until hardware realization. Particular emphasis is made on the methods to support high system performance, meet application requirements, and provide a user-friendly programmer interface. As a result, the research introduces a complete heterogeneous platform enhanced with a hierarchical memory organization, which copes with its task by means of separating computation from communication, providing reconfigurable engines with computation and configuration data, and unification of heterogeneous computational devices using local storage buffers. It is distinguished from the related solutions by distributed data-flow organization, specifically engineered mechanisms to operate with data on local domains, particular communication infrastructure based on Network-on-Chip, and thorough methods to prevent computation and communication stalls. In addition, a novel advanced technique to accelerate memory access was developed and implemented.

Sistemi riconfigurabili a basso consumo per applicazioni di monitoraggio distribuito

The term Ambient Intelligence (AmI) refers to a vision on the future of the information society where smart, electronic environment are sensitive and responsive to the presence of people and their activities (Context awareness). In an ambient intelligence world, devices work in concert to support people in carrying out their everyday life activities, tasks and rituals in an easy, natural way using information and intelligence that is hidden in the network connecting these devices. This promotes the creation of pervasive environments improving the quality of life of the occupants and enhancing the human experience. AmI stems from the convergence of three key technologies: ubiquitous computing, ubiquitous communication and natural interfaces. Ambient intelligent systems are heterogeneous and require an excellent cooperation between several hardware/software technologies and disciplines, including signal processing, networking and protocols, embedded systems, information management, and distributed algorithms. Since a large amount of fixed and mobile sensors embedded is deployed into the environment, the Wireless Sensor Networks is one of the most relevant enabling technologies for AmI. WSN are complex systems made up of a number of sensor nodes which can be deployed in a target area to sense physical phenomena and communicate with other nodes and base stations. These simple devices typically embed a low power computational unit (microcontrollers, FPGAs etc.), a wireless communication unit, one or more sensors and a some form of energy supply (either batteries or energy scavenger modules). WNS promises of revolutionizing the interactions between the real physical worlds and human beings. Low-cost, low-computational power, low energy consumption and small size are characteristics that must be taken into consideration when designing and dealing with WSNs. To fully exploit the potential of distributed sensing approaches, a set of challengesmust be addressed. Sensor nodes are inherently resource-constrained systems with very low power consumption and small size requirements which enables than to reduce the interference on the physical phenomena sensed and to allow easy and low-cost deployment. They have limited processing speed,storage capacity and communication bandwidth that must be efficiently used to increase the degree of local ”understanding” of the observed phenomena. A particular case of sensor nodes are video sensors. This topic holds strong interest for a wide range of contexts such as military, security, robotics and most recently consumer applications. Vision sensors are extremely effective for medium to long-range sensing because vision provides rich information to human operators. However, image sensors generate a huge amount of data, whichmust be heavily processed before it is transmitted due to the scarce bandwidth capability of radio interfaces. In particular, in video-surveillance, it has been shown that source-side compression is mandatory due to limited bandwidth and delay constraints. Moreover, there is an ample opportunity for performing higher-level processing functions, such as object recognition that has the potential to drastically reduce the required bandwidth (e.g. by transmitting compressed images only when something ‘interesting‘ is detected). The energy cost of image processing must however be carefully minimized. Imaging could play and plays an important role in sensing devices for ambient intelligence. Computer vision can for instance be used for recognising persons and objects and recognising behaviour such as illness and rioting. Having a wireless camera as a camera mote opens the way for distributed scene analysis. More eyes see more than one and a camera system that can observe a scene from multiple directions would be able to overcome occlusion problems and could describe objects in their true 3D appearance. In real-time, these approaches are a recently opened field of research. In this thesis we pay attention to the realities of hardware/software technologies and the design needed to realize systems for distributed monitoring, attempting to propose solutions on open issues and filling the gap between AmI scenarios and hardware reality. The physical implementation of an individual wireless node is constrained by three important metrics which are outlined below. Despite that the design of the sensor network and its sensor nodes is strictly application dependent, a number of constraints should almost always be considered. Among them: • Small form factor to reduce nodes intrusiveness. • Low power consumption to reduce battery size and to extend nodes lifetime. • Low cost for a widespread diffusion. These limitations typically result in the adoption of low power, low cost devices such as low powermicrocontrollers with few kilobytes of RAMand tenth of kilobytes of program memory with whomonly simple data processing algorithms can be implemented. However the overall computational power of the WNS can be very large since the network presents a high degree of parallelism that can be exploited through the adoption of ad-hoc techniques. Furthermore through the fusion of information from the dense mesh of sensors even complex phenomena can be monitored. In this dissertation we present our results in building several AmI applications suitable for a WSN implementation. The work can be divided into two main areas:Low Power Video Sensor Node and Video Processing Alghoritm and Multimodal Surveillance . Low Power Video Sensor Nodes and Video Processing Alghoritms In comparison to scalar sensors, such as temperature, pressure, humidity, velocity, and acceleration sensors, vision sensors generate much higher bandwidth data due to the two-dimensional nature of their pixel array. We have tackled all the constraints listed above and have proposed solutions to overcome the current WSNlimits for Video sensor node. We have designed and developed wireless video sensor nodes focusing on the small size and the flexibility of reuse in different applications. The video nodes target a different design point: the portability (on-board power supply, wireless communication), a scanty power budget (500mW),while still providing a prominent level of intelligence, namely sophisticated classification algorithmand high level of reconfigurability. We developed two different video sensor node: The device architecture of the first one is based on a low-cost low-power FPGA+microcontroller system-on-chip. The second one is based on ARM9 processor. Both systems designed within the above mentioned power envelope could operate in a continuous fashion with Li-Polymer battery pack and solar panel. Novel low power low cost video sensor nodes which, in contrast to sensors that just watch the world, are capable of comprehending the perceived information in order to interpret it locally, are presented. Featuring such intelligence, these nodes would be able to cope with such tasks as recognition of unattended bags in airports, persons carrying potentially dangerous objects, etc.,which normally require a human operator. Vision algorithms for object detection, acquisition like human detection with Support Vector Machine (SVM) classification and abandoned/removed object detection are implemented, described and illustrated on real world data. Multimodal surveillance: In several setup the use of wired video cameras may not be possible. For this reason building an energy efficient wireless vision network for monitoring and surveillance is one of the major efforts in the sensor network community. Energy efficiency for wireless smart camera networks is one of the major efforts in distributed monitoring and surveillance community. For this reason, building an energy efficient wireless vision network for monitoring and surveillance is one of the major efforts in the sensor network community. The Pyroelectric Infra-Red (PIR) sensors have been used to extend the lifetime of a solar-powered video sensor node by providing an energy level dependent trigger to the video camera and the wireless module. Such approach has shown to be able to extend node lifetime and possibly result in continuous operation of the node.Being low-cost, passive (thus low-power) and presenting a limited form factor, PIR sensors are well suited for WSN applications. Moreover techniques to have aggressive power management policies are essential for achieving long-termoperating on standalone distributed cameras needed to improve the power consumption. We have used an adaptive controller like Model Predictive Control (MPC) to help the system to improve the performances outperforming naive power management policies.

Semantic Publishing: issues, solutions and new trends in scholarly publishing within the Semantic Web era

This work is concerned with the increasing relationships between two distinct multidisciplinary research fields, Semantic Web technologies and scholarly publishing, that in this context converge into one precise research topic: Semantic Publishing. In the spirit of the original aim of Semantic Publishing, i.e. the improvement of scientific communication by means of semantic technologies, this thesis proposes theories, formalisms and applications for opening up semantic publishing to an effective interaction between scholarly documents (e.g., journal articles) and their related semantic and formal descriptions. In fact, the main aim of this work is to increase the users' comprehension of documents and to allow document enrichment, discovery and linkage to document-related resources and contexts, such as other articles and raw scientific data. In order to achieve these goals, this thesis investigates and proposes solutions for three of the main issues that semantic publishing promises to address, namely: the need of tools for linking document text to a formal representation of its meaning, the lack of complete metadata schemas for describing documents according to the publishing vocabulary, and absence of effective user interfaces for easily acting on semantic publishing models and theories.

Integrative Musterbildung kranialer Strukturen

Form und Gestalt kraniofazialer Strukturen sind primär beeinflusst durch die inhärente Integration der unterschiedlichsten Funktionssysteme und externer selektiver Einflüsse. Die Variabilität der Schädel-Morphe ist ein Indikator für solche Einflussfaktoren und damit ein idealer Gegenstand für vergleichende Analysen morphogenetischer Formbildung. Zur Ermittlung morphologisch-adaptiver Trends und Muster wurden sowohl Hypothesen zur morphologischen Differenziertheit als auch zu Korrelationen zwischen modularen Schädelkompartimenten (fazial, neurokranial, basikranial) untersucht. Zusätzlich wurden aus Schichtröntgenaufnahmen (CT) virtuelle Modelle rekonstruiert, welche die Interpretation der statistischen Befunde unterstützen sollten. Zur Berechnung der Gestaltunterschiede wurden mittels eines mechanischen Gelenkarm-Messgerätes (MicroScribe-G2) max. 85 ektokraniale Messpunkte (Landmarks) bzw. dreidimensionale Koordinaten an ca. 520 Schädeln von fünf rezenten Gattungen der Überfamilie Hominoidea (Hylobates, Pongo, Gorilla, Pan und Homo) akquiriert. Aus dem Datensatz wurden geometrische Störfaktoren (Größe, Translation, Rotation) mathematisch eliminiert und die verbleibenden Residuale bzw. ‚Gestalt-Variablen‘ diversen multivariat-statistischen Verfahren unterzogen (Faktoren, Cluster-, Regressions- und Korrelationsanalysen sowie statistische Tests). Die angewandten Methoden erhalten die geometrische Information der Untersuchungsobjekte über alle Analyseschritte hinweg und werden unter der Bezeichnung „Geometric Morphometrics (GMM)“ als aktueller Ansatz der Morphometrie zusammengefasst. Für die unterschiedlichen Fragestellungen wurden spezifische Datensätze generiert. Es konnten diverse morphologische Trends und adaptive Muster mit Hilfe der Synthese statistischer Methoden und computer-basierter Rekonstruktionen aus den generierten Datensätzen ermittelt werden. Außerdem war es möglich, präzise zu rekonstruieren, welche kranialen Strukturen innerhalb der Stichprobe miteinander wechselwirken, einzigartige Variabilitäten repräsentieren oder eher homogen gestaltet sind. Die vorliegenden Befunde lassen erkennen, dass Fazial- und Neurokranium am stärksten miteinander korrelieren, während das Basikranium geringe Abhängigkeiten in Bezug auf Gesichts- oder Hirnschädelveränderungen zeigte. Das Basikranium erweist sich zudem bei den nicht-menschlichen Hominoidea und über alle Analysen hinweg als konservative und evolutiv-persistente Struktur mit dem geringsten Veränderungs-Potential. Juvenile Individuen zeigen eine hohe Affinität zueinander und zu Formen mit einem kleinem Gesichts- und großem Hirnschädel. Während das Kranium des rezenten Menschen primär von Enkephalisation und fazialer Retraktion (Orthognathisierung) dominiert ist und somit eine einzigartige Gestalt aufweist, zeigt sich der Kauapparat als maßgeblich formbildendes Kompartiment bei den nicht-menschlichen Formen. Die Verbindung von GMM mit den interaktiven Möglichkeiten computergenerierter Modelle erwies sich als valides Werkzeug zur Erfassung der aufgeworfenen Fragestellungen. Die Interpretation der Befunde ist durch massive Interkorrelationen der untersuchten Strukturen und der statistisch-mathematischen Prozeduren als hoch komplex zu kennzeichnen. Die Studie präsentiert einen innovativen Ansatz der modernen Morphometrie, welcher für zukünftige Untersuchungen im Bereich der kraniofazialen Gestaltanalyse ausgebaut werden könnte. Dabei verspricht die Verknüpfung mit ‚klassischen’ und modernen Zugängen (z. B. Molekularbiologie) gesteigerte Erkenntnismöglichkeiten für künftige morphometrische Fragestellungen.

Parallel Architectures for Many-Core Systems-On-Chip in Deep Sub-Micron Technology

Despite the several issues faced in the past, the evolutionary trend of silicon has kept its constant pace. Today an ever increasing number of cores is integrated onto the same die. Unfortunately, the extraordinary performance achievable by the many-core paradigm is limited by several factors. Memory bandwidth limitation, combined with inefficient synchronization mechanisms, can severely overcome the potential computation capabilities. Moreover, the huge HW/SW design space requires accurate and flexible tools to perform architectural explorations and validation of design choices. In this thesis we focus on the aforementioned aspects: a flexible and accurate Virtual Platform has been developed, targeting a reference many-core architecture. Such tool has been used to perform architectural explorations, focusing on instruction caching architecture and hybrid HW/SW synchronization mechanism. Beside architectural implications, another issue of embedded systems is considered: energy efficiency. Near Threshold Computing is a key research area in the Ultra-Low-Power domain, as it promises a tenfold improvement in energy efficiency compared to super-threshold operation and it mitigates thermal bottlenecks. The physical implications of modern deep sub-micron technology are severely limiting performance and reliability of modern designs. Reliability becomes a major obstacle when operating in NTC, especially memory operation becomes unreliable and can compromise system correctness. In the present work a novel hybrid memory architecture is devised to overcome reliability issues and at the same time improve energy efficiency by means of aggressive voltage scaling when allowed by workload requirements. Variability is another great drawback of near-threshold operation. The greatly increased sensitivity to threshold voltage variations in today a major concern for electronic devices. We introduce a variation-tolerant extension of the baseline many-core architecture. By means of micro-architectural knobs and a lightweight runtime control unit, the baseline architecture becomes dynamically tolerant to variations.

Impact of metal and metal oxide engineered nanoparticles in soil and plant systems

Nanotechnology promises huge benefits for society and capital invested in this new technology is steadily increasing, therefore there is a growing number of nanotechnology products on the market and inevitably engineered nanomaterials will be released in the atmosphere with potential risks to humans and environment. This study set out to extend the comprehension of the impact of metal (Ag, Co, Ni) and metal oxide (CeO2, Fe3O4, SnO2, TiO2) nanoparticles (NPs) on one of the most important environmental compartments potentially contaminated by NPs, the soil system, through the use of chemical and biological tools. For this purpose experiments were carried out to simulate realistic environmental conditions of wet and dry deposition of NPs, considering ecologically relevant endpoints. In detail, this thesis involved the study of three model systems and the evaluation of related issues: (i) NPs and bare soil, to assess the influence of NPs on the functions of soil microbial communities; (ii) NPs and plants, to evaluate the chronic toxicity and accumulation of NPs in edible tissues; (iii) NPs and invertebrates, to verify the effects of NPs on earthworms and the damaging of their functionality. The study highlighted that NP toxicity is generally influenced by NP core elements and the impact of NPs on organisms is specie-specific; moreover experiments conducted in media closer to real conditions showed a decrease in toxicity with respect to in vitro test or hydroponic tests. However, only a multidisciplinary approach, involving physical, chemical and biological skills, together with the use of advanced techniques, such as X-ray absorption fine structure spectroscopy, could pave the way to draw the right conclusions and accomplish a deeper comprehension of the effects of NPs on soil and soil inhabitants.

Immunologische Effekte von nativen Allergenen im Vergleich zu modifizierten Allergenen

Die Prävalenz allergischer Erkrankungen ist in den letzten Jahrzehnten, insbesondere in den Industriestaaten, stetig angestiegen und schreitet weiterhin fort. Die einzige kausale Therapie, die eine Langzeitwirkung verspricht und der Entwicklung neuer Allergien bzw. dem Fortschreiten der Allergie vorbeugen kann, ist die spezifische Immuntherapie (SIT). Da bei der SIT mit natürlichen Allergenextrakten Nebenwirkungen auftreten können, ist es wichtig Alternativen für diese zu finden. In der vorliegenden Arbeit wurden native Allergene mit modifizierten Allergenen hinsichtlich ihrer Allergenität und Immunogenität verglichen. Hierbei konnte gezeigt werden, dass Glutaraldehyd-modifizierte Allergoide im Vergleich zu nativen Allergenextrakten und Formaldehyd-Allergoiden eine verminderte Allergenität besitzen, was sich z.B. durch den verminderten Release der Allergiemediatoren, den Leukotrienen, durch Basophile allergischer Spender zeigte. Gleichzeitig war allerdings die Fähigkeit Glutaraldehyd-Allergoid-behandelter dendritischer Zellen (DC) autologe CD4+ T-Zellen zu stimulieren stark reduziert. Verglichen mit den nativen Allergenextrakten und den Formaldehyd-Allergoiden waren die Zytokinproduktion und die T-Zellproliferation, für letztere signifikant, vermindert. Damit übereinstimmend war die Aufnahme von Fluoreszenz-markierten Glutaraldehyd-Allergoiden in unreife DC reduziert. Daraus lässt sich schießen, dass die Modifizierung mit Glutaraldehyd, jedoch nicht mit Formaldehyd, zumindest bei den hier verwendeten Allergenpräparaten, B-Zell-Epitope zerstört und somit die Allergenität herabgesetzt wurde. Allerdings war dabei gleichzeitig die Immunogenität vermindert. Das verminderte Vorkommen der B-Zell-Epitope wäre beim Einsatz der Allergoide von Vorteil, da damit eine verminderte IgE-Bindekapazität einhergeht und unerwünschte Nebenwirkungen reduziert werden können. Jedoch sollte im günstigsten Fall bei der Allergoidisierung die T-Zell-Stimulationsfähigkeit intakt bleiben, was bei den hier verwendeten Glutaraldehyd-modifizierten Allergoiden nicht der Fall war. rnMit Einzelallergenen aus Birken- und Gräserpollen konnten keine vergleichbaren T-Zellantworten erzielt werden wie mit den Gesamtallergenextrakten. Auch hier waren Proliferation und Zytokinproduktion durch CD4+ T-Zellen nach Stimulation mit Einzelallergen-gepulsten DC bei Verwendung von Glutaraldehyd-modifizierten Allergoiden vermindert. rnEine adjuvante Wirkung von Aluminiumhydroxid (Alum) in vitro konnte in dieser Arbeit nicht eindeutig gezeigt werden. Zunächst konnte beobachtet werden, dass die eingesetzten Alum-adsorbierten Allergene und Allergoide eine toxische Wirkung auf DC hatten. Die Proliferation CD4+ T-Zellen konnte durch DC, die mit Alum-adsorbierten Allergenen behandelt wurden, nicht verstärkt werden, verglichen mit DC, die mit unadsorbiertem Allergen gepulst wurden. Es konnte lediglich eine erhöhte Produktion des Th2 Zytokins IL-4 durch Alum induziert werden. Einen Adjuvanteffekt, der in Zusammenhang mit der Induktion des pro-inflammatorischen Zytokins IL-1β stehen soll, konnte mittels ELISA in den Überständen unreifer DC nicht nachgewiesen werden. Lediglich in Monozyten, die zusätzlich mit dem TLR-Ligand LPS stimuliert wurden, war IL-1β in den Überständen detektierbar. Auf mRNA-Ebene konnte man einen leichten Effekt durch Alum hinsichtlich der IL-1β Expression erkennen. Nach zusätzlicher Gabe verschiedener Alum-Präparationen zu unreifen DC, die mit Allergen oder LPS stimuliert wurden, exprimierten diese leicht verstärkt IL-1β verglichen mit DC, die kein Alum erhielten.

Microfluidic microbial fuel cell fabrication and rapid screening of electrochemically microbes

The demand for novel renewable energy sources, together with the new findings on bacterial electron transport mechanisms and the progress in microbial fuel cell design, have raised a noticeable interest in microbial power generation. Microbial fuel cell (MFC) is an electrochemical device that converts organic substrates into electricity via catalytic conversion by microorganism. It has represented a continuously growing research field during the past few years. The great advantage of this device is the direct conversion of the substrate into electricity and in the future, MFC may be linked to municipal waste streams or sources of agricultural and animal waste, providing a sustainable system for waste treatment and energy production. However, these novel green technologies have not yet been used for practical applications due to their low power outputs and challenges associated with scale-up, so in-depth studies are highly necessary to significantly improve and optimize the device working conditions. For the time being, the micro-scale MFCs show great potential in the rapid screening of electrochemically active microbes. This thesis presents how it will be possible to optimize the properties and design of the micro-size microbial fuel cell for maximum efficiency by understanding the MFC system. So it will involve designing, building and testing a miniature microbial fuel cell using a new species of microorganisms that promises high efficiency and long lifetime. The new device offer unique advantages of fast start-up, high sensitivity and superior microfluidic control over the measured microenvironment, which makes them good candidates for rapid screening of electrode materials, bacterial strains and growth media. It will be made in the Centre of Hybrid Biodevices (Faculty of Physical Sciences and Engineering, University of Southampton) from polymer materials like PDMS. The eventual aim is to develop a system with the optimum combination of microorganism, ion exchange membrane and growth medium. After fabricating the cell, different bacteria and plankton species will be grown in the device and the microbial fuel cell characterized for open circuit voltage and power. It will also use photo-sensitive organisms and characterize the power produced by the device in response to optical illumination.

Dynamics of small interfering RNA - FRET based integrity measurements of siRNA in the cuvette & inside cells

RNAi ist ein bedeutendes Werkzeug zur Funktionsanalyse von Genen und hat großes Potential für den Einsatz in der Therapie. Obwohl effiziente Knockdowns in der Zellkultur erzielt werden, erweist sich eine in vivo Anwendung als schwierig. Die großen Hürden sind dabei der Transport der siRNA ins Zielgewebe und deren voranschreitende Degradierung.rnMarkierte siRNA kann sowohl zur eigenen Integritätsmessung als auch zur Lokalisierung verwendet werden. Zwei Farbstoffe an den jeweiligen 3’- bzw. -5’-Enden des Sense- bzw. Antisense-Stranges erzeugen ein robustes FRET-System (Hirsch et al. 2012). Das Verhältnis von FRET- zu Donor-Signal, das R/G-Ratio, dient zur sensitiven Klassifizierung des Integritätslevels einer siRNA Probe (Järve et al. 2007; Hirsch et al. 2011; Kim et al. 2010). Mit diesem System kann eine Degradierung von weniger als 5 % in der Küvette und in Zellen nachgewiesen werden.rnDie vorliegende Arbeit beschäftigt sich mit der Evaluierung von potentiellen FRET Farbstoffpaaren hinsichtlich deren Eignung für in vitro und in vivo Anwendung. Verschiedenste FRET-Paare, die das gesamte sichtbare Spektrum abdecken, wurden evaluiert und ermöglichen nun die Auswahl eines geeigneten Paares für die jeweilige Anwendung oder Kombination mit anderen Farbstoffen.rnMit Hilfe von Alexa555/Atto647N siRNA wurde ein erfolgreicher Einschluss von siRNA in Liposomen beobachtet. Eine anschließende Evaluierung der RNase-Protektion ergab für Liposomen, Nanohydrogele und kationische Peptide hervorragende protektive Eigenschaften. Basierend auf den Ergebnisse können diese und andere Transportsysteme nun für eine zelluläre Aufnahme optimiert werden.rnAtto488/Atto590 zeigte die besten Eigenschaften für Echtzeit-Integritätsmessungen in der Lebendzellmikroskopie. Verringerte Bleicheigenschaften und minimaler spektraler “Cross-Talk” ermöglichten es, transfizierte Zellen über einen Zeitraum von bis zu 8 Stunden zu beobachten. Mittels Atto488/Atto590 siRNA wurde die Einschleusung und Freisetzung in Zellen in Echtzeit untersucht. Dabei konnten Freisetzung und Verteilung in einzelnen Zellen beobachtet und analysiert werden. rnAuf eine anfängliche Phase mit hoher Freisetzungsrate folgte eine Phase mit geringerer Rate für den restlichen Beobachtungszeitraum. Die durchschnittliche Verweildauer im Zytosol betrug 24 und 58 Minuten, wobei zwischen lang- und kurzanhaltenden Ereignissen unterschieden werden konnte. Obwohl ein Import von siRNA in den Zellkern beobachtet wurde, konnte kein Schema bzw. genauer Zeitpunkt, in Bezug auf den Transfektionszeitraum für diese Ereignisse bestimmt werden. Die beobachteten Freisetzungsprozesse fanden sporadisch statt und Änderungen in der zellulären Verteilung geschahen innerhalb von wenigen Minuten. Einmal freigesetzte siRNA verschwand mit der Zeit wieder aus dem Zytosol und es blieben nur kleine Aggregate von siRNA mit immer noch geringer Integrität zurück.rn

Patches of Bare Ground as a Staple Commodity for Declining Ground-Foraging Insectivorous Farmland Birds

Conceived to combat widescale biodiversity erosion in farmland, agri-environment schemes have largely failed to deliver their promises despite massive financial support. While several common species have shown to react positively to existing measures, rare species have continued to decline in most European countries. Of particular concern is the status of insectivorous farmland birds that forage on the ground. We modelled the foraging habitat preferences of four declining insectivorous bird species (hoopoe, wryneck, woodlark, common redstart) inhabiting fruit tree plantations, orchards and vineyards. All species preferred foraging in habitat mosaics consisting of patches of grass and bare ground, with an optimal, species-specific bare ground coverage of 30–70% at the foraging patch scale. In the study areas, birds thrived in intensively cultivated farmland where such ground vegetation mosaics existed. Not promoted by conventional agri-environment schemes until now, patches of bare ground should be implemented throughout grassland in order to prevent further decline of insectivorous farmland birds.