Caratterizzazione funzionale di Djmot,un gene omologo a “mortalin/mthsp70/GRP75” nelle planarie

Le planarie, invertebrati a simmetria bilaterale, sono caratterizzate da un’elevata plasticità corporea e da una straordinaria abilità rigenerativa. Queste caratteristiche sono dovute alla presenza di una popolazione di cellule staminali pluripotenti, chiamate neoblasti. I neoblasti hanno la capacità di dare origine a tutti i tipi di cellule differenziate di questi organismi e sono responsabili della formazione del blastema rigenerativo. Dati di letteratura dimostrano che le Heat Shock Proteins (HSPs) hanno un ruolo centrale nei processi di omeostasi cellulare. Sono inoltre specificamente attivate in seguito ad eventi di stress diversi intervenendo in diversi processi cellulari. In questo lavoro di tesi ho analizzato preliminarmente alcuni geni che codificano differenti proteine “heat shock”, ed in particolare, ho caratterizzato un clone (Dj22v), isolato precedentemente in laboratorio e codificante un frammento proteico che mostra elevata similarità con la mortalina (mortalin/mtHsp70/Grp75), un membro peculiare della famiglia delle HSP70, attivato in tumori e in cellule di mammifero immortalizzate. Questo gene è stato completato mediante RACE (Rapid Amplification of cDNA Ends) e chiamato Djmot. La sua espressione è stata analizzata in planarie intatte e rigeneranti. Djmot ha un’espressione diffusa nel parenchima che scompare in seguito ad irraggiamento con raggi X, indicando che il gene può essere espresso nelle cellule radiosensibili delle planarie, cioè i neoblasti. Interessantemente, l’irraggiamento causa un’attivazione transiente a livello del gastroderma e, successivamente, nel sistema nervoso centrale. Djmot non è attivato durante la rigenerazione e dopo lo shock termico, mentre la sua espressione è regolata dal digiuno. Esperimenti funzionali, condotti mediante la tecnica di RNA interference (RNAi), dimostrano che Djmot svolge un ruolo vitale in questi animali contribuendo alla citoprotezione dei neoblasti. L’ablazione funzionale di questo gene non permette infatti la formazione del blastema rigenerativo o causa alterazioni nella sua morfogenesi. Nell’insieme questi studi forniscono la prima evidenza sperimentale del coinvolgimento funzionale di geni “hsp” nella risposta adattativa delle cellule staminali delle planarie

Stochastic Control of Inertial Sea Wave Energy Converter

The ISWEC (inertial sea wave energy converter) is presented, its control problems are stated, and an optimal control strategy is introduced. As the aim of the device is energy conversion, the mean absorbed power by ISWEC is calculated for a plane 2D irregular sea state. The response of the WEC (wave energy converter) is driven by the sea-surface elevation, which is modeled by a stationary and homogeneous zero mean Gaussian stochastic process. System equations are linearized thus simplifying the numerical model of the device. The resulting response is obtained as the output of the coupled mechanic-hydrodynamic model of the device. A stochastic suboptimal controller, derived from optimal control theory, is defined and applied to ISWEC. Results of this approach have been compared with the ones obtained with a linear spring-damper controller, highlighting the capability to obtain a higher value of mean extracted power despite higher power peaks

FEM-Aided Structural Design of a Natural Fiber Composite Made Skiff

In racing boat design, the research is moved to find always the best compromise between performance and safety. The present work focuses on the description of the structural design cycle used by Polito Sailing Team during the realization of its new skiff, a high-performance sailing dinghy, built mainly with natural composite material such as balsa wood and flax fiber. The whole boat was completely designed by students, according to eco-sustainable principles, to participate in a universities competition called 1001VelaCup. To determinate the sandwich composite stratification, a benchmarking of materials was made by mechanical tests run according to ASTM 3039 and 3518 regulations. A finite element (FE) model was built to evaluate the static response of the structure, aiming to obtain a safe and light hull. The fluid (sea) interaction is modeled with a linear springs system. The crew, rig and rigging loads are obtained from a one-dimensional model and hydrodynamics pressure from ISO 12215-5:2014. The outputs obtained are consistent with the physics of the problem and the stresses distribution shows that the maximum stress is in the proximity of the mast base. This work constitutes the first step to obtain a correct, reliable and innovative design tool

Wave Tank Testing of a Pendulum Wave Energy Converter 1:12 Scale Model

Wave Energy is a widespread, reliable renewable energy source. The early study on Wave Energy dates back in the 70's, with a particular effort in the last and present decade to make Wave Energy Converters (WECs) more profitable and predictable. The PeWEC (Pendulum Wave Energy Converter) is a pendulum-based WEC. The research activities described in the present work aim to develop a pendulum converter for the Mediterranean Sea, where waves are shorter, thus with a higher frequency compared to the ocean waves, a characteristic well agreeing with the PeWEC frequency response. The mechanical equations of the device are developed and coupled with the hydrodynamic Cummins equation. The work deals with the design and experimental tank test of a 1:12 scale prototype. The experimental data recorded during the testing campaign are used to validate the numerical model previously described. The numerical model proved to be in good agreement with the experiments

Evaluation of the starting point of the Lombard Effect.

Speakers increase their vocal effort when their communication is disturbed by noise. This adaptation is termed the Lombard effect. The aim of the present study was to determine whether this effect has a starting point. Hence, the effects of noise at levels between 20 and 65 dB(A) on vocal effort (quantified by sound pressure level) and on both perceived noise disturbance and perceived vocal discomfort were evaluated. Results indicate that there is a Lombard effect change-point at a background noise level (Ln) of 43.3 dB(A). This change-point is anticipated by noise disturbance, and is followed by a high magnitude of vocal discomfort

Stochastic control applied to the ISWEC Wave Energy System

ISWEC (Inertial Sea Wave Energy Converter) is a fl oating marine device able to harvest sea waves energy by the interaction between the pitching motion of a fl oater and a spinning fl ywheel which can drive an electric PTO. In the ISWEC the hull dynamics is governed and controlled by the gyroscopic torque. The optimal control logic results in tuning the fl oater dynamics to the incoming waves in order to maximize the power transfer from the waves to the fl oater. In this paper the control problems of the ISWEC are stated and a control scheme based on the sub-optimal stochastic control logic is presented. The control scheme here presented has been tested using real wave records acquired at the deployment location in Pantelleria Island, which is one of the most energetic sites of the Mediterranean Sea

History, power, and electricity: American popular magazine accounts of electroconvulsive therapy, 1940–2005

Electroconvulsive therapy (ECT) is a psychiatric treatment that has been in use in the United States since the 1940s. During the whole of its existence, it has been extensively discussed and debated within American popular magazines. While initial reports of the treatment highlighted its benefits to patients, accounts by the 1970s and 1980s were increasingly polarized. This article analyzes the popular accounts over time, particularly the ways in which the debates over ECT have revolved around different interpretations of ECT's history and its power dynamics. © 2008Wiley Periodicals, Inc.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/57903/1/20283_ftp.pd

Energy storage for wave energy conversion

In a world characterized by a continuous growth of the population, the energy sources management becomes the most important challenge. In order to guarantee the sustainable development using the different sources in a smart way first of all it is necessary to have a large variety in the energy mix. Renewable energy sources play a fundamental role in this challenge and they find the optimal exploitation in the distributed power generation organized through smart grids. One of the bigger problems of the renewables it is the non-concurrence in time between energy production and energy loads. The solution of this problem is another great challenge: the development and the design of efficient energy storage. Depending on the area of interest and on the particular power plant it will be critical to make a convenient and suitable choice of the storage type: thermal, electrical, chemical, mechanical. The technology that I am developing with my research group is a Wave Energy Converter (WEC) which exploits the gyroscopic effects of a flywheel in order to convert the mechanical energy of the sea waves into electrical energy. This device already presents a mechanical storage consisting in the flywheel but the real challenge to deal with is on the electrical part of the energy conversion. Being the energy source (sea waves) strongly irregular and characterized by high power peaks, in order to have a feasible grid connection it is necessary to have a smoother electrical power profile. A storage capacity can absolutely help in this problem. For this purpose the most suitable technology has not been already identified. To study the different opportunities and to gain a whole comprehension of the advantages and of the disadvantages for each one is essential in order to make the right choice for the technology that I’m dealing with. On the other hand it will be very useful to understand which kind of storage is the most suitable for each kind of renewable energy system. Furthermore to have the chance to apply the storage concept to a real innovative application it would be very interesting to highlight all the properties required by a good energy storage for smart grids development