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

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

LDOC1 expression in fibroblasts of patients with Down syndrome

Abstract Down syndrome (DS) is characterised by intellectual disability and is caused by trisomy 21. Apoptosis is a programmed cell death process and is involved in neurodegenerative diseases such as Alzheimer. People with DS can develop some traits of Alzheimer disease at an earlier age than subjects without trisomy 21. The leucine zipper, down regulated in cancer 1 (LDOC1) appears to be involved in the apoptotic pathways. The aim of the present work was to detect the presence of intracellular synthesis of LDOC1 protein and LDOC1 mRNA in fibroblast cultures from DS subjects. The western blot shows the presence of LDOC1 protein in fibroblasts of DS subjects but no evidence of LDOC1 protein in fibroblasts of normal subjects. LDOC1 gene mRNA expression is increased in fibroblasts from DS subjects compared to fibroblasts from normal subjects. The data obtained from this study strengthen the hypothesis that the over-expression of LDOC1 gene could play a role in determining the phenotype of individuals with DS but does not exclude that this results from apoptotic mechanisms

Poly (ADP-ribose) polymerase 1 expression in fibroblasts of Down syndrome subjects

Abstract Down syndrome (DS) is the most common chromosomal disorder. It is featured by intellectual disability and is caused by trisomy 21. People with DS can develop some traits of Alzheimer disease at an earlier age than subjects without trisomy 21. Apoptosis is a programmed cell death process under both normal physiological and pathological conditions. Poly (ADP-ribose) polymerase 1 is a mediator of programmed-necrotic cell death and appears to be also involved in the apoptosis. The aim of the present work was to detect the intracellular distribution of PARP-1 protein using immunofluorescence techniques and the expression of PARP-1 mRNA in culture of fibroblasts of DS subjects. The analysis of the intracellular distribution of PARP-1 show a signal at the nuclear level in about 75 % of the cells of DS subjects with a slight uniformly fluorescent cytoplasm. In contrast, in about 65% of the analyzed fibroblasts of the normal subjects only a slight fluorescent was found. These observations have been confirmed by PARP-1 gene mRNA expression evaluation. The data obtained from this study strengthen the hypothesis that the over-expression of PARP-1 gene could have a role in the activation of the apoptotic pathways acting in the neurodegenerative processes in DS