PTEN Gene: A Model for Genetic Diseases in Dermatology

PTEN gene is considered one of the most mutated tumor suppressor genes in human cancer, and it's likely to become the first one in the near future. Since 1997, its involvement in tumor suppression has smoothly increased, up to the current importance. Germline mutations of PTEN cause the PTEN hamartoma tumor syndrome (PHTS), which include the past-called Cowden, Bannayan-Riley-Ruvalcaba, Proteus, Proteus-like, and Lhermitte-Duclos syndromes. Somatic mutations of PTEN have been observed in glioblastoma, prostate cancer, and brest cancer cell lines, quoting only the first tissues where the involvement has been proven. The negative regulation of cell interactions with the extracellular matrix could be the way PTEN phosphatase acts as a tumor suppressor. PTEN gene plays an essential role in human development. A recent model sees PTEN function as a stepwise gradation, which can be impaired not only by heterozygous mutations and homozygous losses, but also by other molecular mechanisms, such as transcriptional regression, epigenetic silencing, regulation by microRNAs, posttranslational modification, and aberrant localization. The involvement of PTEN function in melanoma and multistage skin carcinogenesis, with its implication in cancer treatment, and the role of front office in diagnosing PHTS are the main reasons why the dermatologist should know about PTEN

A Mathematical Tool for Optimising Carbon Capture, Utilisation and Sequestration Plants for e-MeOH Production

Carbon capture, utilisation, and sequestration is key for the decarbonisation of hard-to-abate industries, as it allows avoiding the direct release of CO2 to the atmosphere and generating carbon-based products. However, for these products to be truly carbon-neutral, intermittent renewable electricity must be deployed at scale, leading to the necessity of optimising flexible plants with potential for local buffer storages, geological sequestration, and conversion units. The scope of this work is to provide a mathematical framework for the economic optimisation of a carbon capture, utilisation, and sequestration system, to decarbonise a cement plant located in the Puglia region (Italy), via CO2 geological confinement and/or power and CO2-to-methanol conversion. The final aim is to determine the optimal sizing and cost of the process units of the plant, depending on economic conditions such as the methanol sale price and different perspective costs scenarios. The main outcome is an economic convenience of geological sequestration, as opposed to utilisation, while a long-term scenario would allow for a cost-effective production of methanol when the sale price is above 550 EUR/t

Techno-economic study of chimneyless electric arc furnace plants for the coproduction of steel and of electricity, hydrogen, or methanol

Electric arc furnace (EAF) is the most common technology for steel production from steel scrap. Although the input energy is mostly constituted by electricity, significant amounts of carbon dioxide are emitted with the exhaust gases, most of which are classifiable as process-related. The main goal of this study is to perform a techno-economic analysis of chimneyless electric arc furnace plants, fed by either scrap or direct reduced iron (DRI), and able to coproduce steel as well as electricity, hydrogen, or methanol. Several plant configurations are investigated, featuring different combinations of oxy-postcombustion, carbon capture, carbon monoxide-rich gas recovery, hydrogen or syngas production by high-temperature electrolysis or coelectrolysis, and methanol synthesis. These configurations are also characterized by decreased false air leakage and by heat recovery for steam production. Results show that all cases allow achieving a substantial reduction of direct carbon dioxide emissions, close to 99% compared to the unabated conditions. From an economic perspective, in a long-term scenario, the internal rate of return is always above 8%, and up to 73% for the DRI-fed case. However, in a short-term scenario, only cases with sole power production are economically viable. Hydrogen and methanol are competitive with market prices only for low electricity costs. In a higher electricity cost scenario, the case of carbon capture and storage is more competitive than the case of carbon capture and utilization. With an electricity cost of 100 €/MWh, a steel premium of 10-40 €/t allows to reach economic feasibility if methanol or hydrogen selling prices are in line with current market conditions. In general, the configurations with DRI-fed furnaces obtain more favorable economic performance than scrap-fed ones. The competitiveness of sole electricity, hydrogen or methanol production configurations depends on the case study and on the future market prices

Oxy-turbine for Power Plant with CO2Capture

The IEA Greenhouse Gas R&D (IEAGHG) programme contracted Amec Foster Wheeler to perform a study providing an evaluation of the performance and costs of a number of oxy-turbine plants for utility scale power generation with CO2capture. The main outcomes of the detailed technical and economical modelling of the most promising oxy-turbine cycles is presented in this paper, including sensitivity analyses on main technical and financial parameters. Each cycle configuration and optimization is developed jointly with the main cycle developers, i.e. Clean Energy Systems, Graz University of Technology and NET Power. The modelling of the gas turbine, including efficiency and blade cooling requirement, have been performed using a calculation code developed by Politecnico di Milano

Thermodynamic assessment of liquid metal–steam USC binary plants to break 50% efficiency in pulverized coal plants

Nowadays the state-of-the-art technology to convert coal energy of combustion into electricity is to adopt a pulverized coal boiler coupled with an Ultra Super Critical (USC) steam cycle. The total installed capacity of this well-proven configuration is of hundreds of GW worldwide with an increasing share respect to both supercritical and subcritical cycles. Typical coal USC cycles have maximum pressures of around 270 bar and maximum temperatures of 600-620°C for the high pressure and the mid pressure steam respectively. Maximum attainable efficiency is close to 45% in favorable locations and is mainly penalized by two irreversible processes: coal combustion (about 30%) and heat introduction (about 10%) that is characterized by large temperature differences between the hot flue gases and the steam. The main strategy to reduce the second loss is focused on the development of new super alloys able to withstand higher temperatures, higher pressures and water corrosion and so bring efficiencies close to 49% in the so called Advanced USC plants (AUSC). However, the increasing of maximum cycle pressure and temperature results in a relatively small increase of cycle efficiency due to the large increase of specific heat around the critical point but, on the other hand, it involves a considerably increase of equipment’s cost. Another option to increase cycle efficiency is represented by the introduction of a high temperature and low pressure power cycle between the flue gases and the steam cycle. In this case, the topping power cycle could be (i) an external combustion gas cycle, (ii) an open gas cycle fueled by syngas produced by coal gasification or (iii) a Rankine cycle that uses a proper working fluid with a very high critical temperature. This study aims to define a number of optimized binary plant configurations with saturated Rankine potassium cycle as top cycle and a conventional USC plant as bottom cycle. Top cycle receives heat from the flue gases within the coal-fired boiler while bottom cycle recovers heat from the top cycle fluid condensation and the flue gases cooling before the Ljunström air preheater. Potassium thermodynamic properties are computed with a proper equation of state calibrated on experimental data from reference [2] and able to predict accurately both the volumetric and the thermodynamic behavior of potassium in liquid, vapor and two-phase conditions. Different liquid metal cycles have been designed and the trends of the main quantities (heat of condensation, turbine isentropic enthalpy drop and plant efficiency) have been correlated to both evaporation and condensation temperatures. This information is implemented in the USC scheme, calculated with an in-house process simulation code GS developed at the Department of Energy at Politecnico di Milano [3], which has been validated and used on hundreds of publications and projects. Analysis is completed by the evaluation of the potassium turbine design in terms of number of stages, need of cross-over and optimal rotational speed. A double condensation level configuration is also considered for the top cycle in order to further reduce the temperature difference between the top cycle condensation and evaporation process in the bottom cycle, which further increases the efficiency. The thermal input of coal to the burner is fixed for all the simulations to 1.66 GW, five plant configurations have been selected as the most promising ones and fairly compared with a conventional USC coal-fired power plant having a calculated efficiency equal to 44.72%. Limiting the maximum potassium temperature at 800°C, which corresponds to an evaporation pressure of 1.5 bar, it is possible to reach electric efficiencies close to 51% with a single condensation level top cycle and value close to 52% with a double condensation level top cycle. Power produced by the metal cycle ranges between 25 and 30% of the net system power output. As general conclusion the adoption of binary cycles with a top Rankine liquid metal cycle is demonstrated to be an attractive option from a thermodynamic point of view leading to an electric efficiency larger than in AUSC plants. However, these binary metal-steam cycles still need to face a number of technical and safety issues mainly related to the use of liquid metals. Technical issues are related to the high temperature of heat exchange surface of the boiler, to the very high vacuum at condenser, the need of limiting air leakages and the design of a turbine expanding a fluid with an increasing liquid fraction. Safety issues are due to working fluid reactivity with water that requires the need of expensive solution to limit fire hazard. [1] World Energy Council, 2016. World Energy Resources: Coal. [2] Reynolds, W.C. Thermodynamic properties in SI - graphs, tables and computational equations for 40 substances. Department of Mechanical Engineering, Stanford Univ., 1979 [3] GECOS, GS software. www.gecos.polimi.it/software/gs.ph

The role of diagnostic imaging and interventional radiology in liver schistosomiasis: A case report of advanced disease

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Packed Bed Ca-Cu Looping Process Integrated with a Natural Gas Combined Cycle for Low Emission Power Production

This work investigates the full process design of a natural gas combined cycle integrated with a packed-bed reactor system where a hydrogen rich gas is produced with inherent CO2capture based of the CaO/CaCO3and Cu/CuO chemical loops. The different stages of this Ca-Cu process were modelled with a dynamic 1D pseudo-homogeneous model, proposing a novel reactor configuration allowing to achieve carbon capture efficiency close to 90%. Process simulations of the whole power plant resulted in electric efficiencies of around 48%LHVand SPECCA of 4.7 MJ/kgCO2. Published by Elsevier Ltd