589 research outputs found

    Methane Production via High Temperature Steam Electrolyser from Renewable Wind Energy: A German Study

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    The transformation of the energy supply needs further development of energy storage technologies in order to integrate the fluctuating renewable energy. The conversion of renewable wind power into green methane offers a technical approach with the necessary storage and Transport capacities. Thus, the concept of Power-to-Gas which is illustrated here by the coupling of wind energy with a High Temperature Steam Electrolyser (HTSE) and a methanation unit enabling the production of green fuel like hydrogen and methane is presented is this paper. In fact, hydrogen can be used as energy carrier as well for the production of green fuels, like methane which is simpler to store and to transport and which can be thus used as storage medium for the stabilization of the electrical power supply as well as fuel for transport and heat sector. Its production using high temperature electrolysis is able to reduce the carbon dioxide emissions if performed with renewable resources. This is the case if the electricity needed for the HTSE comes from a wind turbine and the CO2 needed for the methanation step comes from biogas. For such a plant, the Location and the boundary conditions have a great importance. Thus, this study considers the coupling of a HTSE with a wind turbine and a methanation reactor, and focuses about the site selection, depending of the geographical and economic considerations. The study is limited first to the European area. Schleswig-Holstein is found as a very good location for this plant. It is one of the regions with the largest wind reserves in Germany. This region has also available a lot of Biogas and meets all the other necessary requirements

    Matrix metalloproteinase-13 refines pathological staging of precancerous colorectal lesions

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    An exact classification of precancerous stages of colorectal polyps might improve therapy and patients´ outcome. Here we investigate the association between grade of dysplasia and Matrix metalloproteinase-13 (MMP-13) expression in 137 biopsies from patients with cancerous and non-cancerous colorectal adenomas. A reproducible staining procedure for histologic MMP-13 analysis in routinely fixed colorectal biopsy specimens has been established. A newly adopted immunoreactive scoring system for MMP-13 was demonstrated as reliable readout. The strength of the association between pathologic stage and immunoreactive MMP-13 scoring emphasizes its eligibility for diagnosis in precancerous colorectal lesions

    Serum proteome profiling identifies novel and powerful markers of cystic fibrosis liver disease.

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    Cystic Fibrosis associated liver disease (CFLD) develops in approximately 30% of CF patients. However, routine sensitive diagnostic tools for CFLD are lacking. Within this study, we aimed to identify new experimental biomarkers for the detection of CFLD. 45 CF patients were included in the study and received transient elastography. Differential regulation of 220 different serum proteins was assessed in a subgroup of patients with and without CFLD. Most interesting candidate proteins were further quantified and validated by ELISA in the whole patient cohort. To assess a potential relation of biomarker expression to the degree of hepatic fibrosis, serum biomarkers were further determined in 18 HCV patients where liver histology was available. 43 serum proteins differed at least 2-fold in patients with CFLD compared to those without liver disease as identified in proteome profiling. In ELISA quantifications, TIMP-4 and Endoglin were significantly up-regulated in patients with CFLD as diagnosed by clinical guidelines or increased liver stiffness. Pentraxin-3 was significantly decreased in patients with CFLD. Serum TIMP-4 and Endoglin showed highest values in HCV patients with liver cirrhosis compared to those with fibrosis but without cirrhosis. At a cut-off value of 6.3 kPa, transient elastography compassed a very high diagnostic accuracy and specificity for the detection of CFLD. Among the biomarkers, TIMP-4 and Endoglin exhibited a high diagnostic accuracy for CFLD. Diagnostic sensitivities and negative predictive values were increased when elastography and TIMP-4 and Endoglin were combined for the detection of CFLD. Serum TIMP-4 and Endoglin are increased in CFLD and their expression correlates with hepatic staging. Determination of TIMP-4 and Endoglin together with transient elastography can increase the sensitivity for the non-invasive diagnosis of CFLD

    Matrix metalloproteinase-19 inhibits growth of endothelial cells by generating angiostatin-like fragments from plasminogen

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    <p>Abstract</p> <p>Background</p> <p>Angiogenesis is the process of forming new blood vessels from existing ones and requires degradation of the vascular basement membrane and remodeling of extracellular matrix (ECM) in order to allow endothelial cells to migrate and invade into the surrounding tissue. Matrix metalloproteinases (MMPs) are considered to play a central role in the remodeling of basement membranes and ECM. However, MMPs contribute to vascular remodeling not only by degrading ECM components. Specific MMPs enhance angiogenesis via several ways; they help pericytes to detach from vessels undergoing angiogenesis, release ECM-bound angiogenic growth factors, expose cryptic pro-angiogenic integrin binding sites in the ECM, generate promigratory ECM component fragments, and cleave endothelial cell-cell adhesions. MMPs can also negatively influence the angiogenic process through generating endogenous angiogenesis inhibitors by proteolytic cleavage. Angiostatin, a proteolytic fragment of plasminogen, is one of the most potent antagonists of angiogenesis that inhibits migration and proliferation of endothelial cells. Reports have shown that metalloelastase, pancreas elastase, plasmin reductase, and plasmin convert plasminogen to angiostatin.</p> <p>Results</p> <p>We report here that MMP-19 processes human plasminogen in a characteristic cleavage pattern to generate three angiostatin-like fragments with a molecular weight of 35, 38, and 42 kDa. These fragments released by MMP-19 significantly inhibited the proliferation of HMEC cells by 27% (p = 0.01) and reduced formation of capillary-like structures by 45% (p = 0.05) compared with control cells. As it is known that angiostatin blocks hepatocyte growth factor (HGF)-induced pro-angiogenic signaling in endothelial cells due to structural similarities to HGF, we have analyzed if the plasminogen fragments generated by MMP-19 interfere with this pathway. As it involves the activation of c-met, the receptor of HGF, we could show that MMP-19-dependent processing of plasminogen decreases the phosphorylation of c-met.</p> <p>Conclusion</p> <p>Altogether, MMP-19 exhibits an anti-angiogenic effect on endothelial cells via generation of angiostatin-like fragments.</p

    Marketing As Tool of Resource Efficiency

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    This paper shows the role of marketing in ensuring resource efficiency. It is found that the marketing is one of the methods of saving resources, making them effective in use. The conclusion about the need to use marketing to increase the efficiency of resource management in the organization is justified. It is suggested to use SWOT-analysis as a marketing technique for choosing a particular strategy, significant for the company in the management of resource efficiency. The forecasting of demand allows receiving evidence-based options in tendencies of change, indicators of quality, expenses and other indicators. Therefore, the system of the resource efficiency at an enterprise has to be guided by forecasting the demand and its task. Improved analysis cost methods (such as the factorial analysis, the functional and cost analysis) help to solve a problem of resource efficiency at the stage of design or production improvement. It is proved that application of the concept of social and ethic marketing promotes development of the resource efficiency program in management

    Performance Analysis and Optimization of Solar Thermochemical Water-Splitting Cycle with Single and Multiple Receivers

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    Solar thermochemical water-splitting cycle models for hydrogen production with single and multiple receivers working between 1773 and 1173 K are developed. The receiver pressures and aperture sizes are optimized for maximum cycle efficiency. The efficiency of the cycle increases with the number of receivers because of the decrease in vacuum pump work. The solar-to-fuel efficiency is increased by 14% going from a one receiver system to a four-receiver system. The performance analyses of the cycles with varying direct normal irradiance (DNI) shows that the advantage of multiple receivers vanishes as DNI decreases because of the constant radiation losses from the receiver apertures. These radiation losses from the aperture can be lowered when a receiver with a variable aperture size is used. The efficiency of a two-receiver system increases by 48% at DNI 300 W m−2% and 15% at DNI 900 W m−2 using a variable aperture size. The performance of the multireceiver systems with variable aperture size is discussed using a linear regression model. In addition, the option of cogeneration of hydrogen and electricity in a multireceiver system is analyzed. The efficiencies of single-, two-, three-, and four-receiver systems for cogeneration are 19.6%, 20.0%, 20.57%, and 21.1%, respectively

    Hepatitis B virus surface proteins accelerate cholestatic injury and tumor progression in Abcb4-knockout mice

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    Understanding of the pathophysiology of cholestasis associated carcinogenesis could challenge the development of new personalized therapeutic approaches and thus improve prognosis. Simultaneous damage might aggravate hepatic injury, induce chronic liver disease and even promote carcinogenesis. We aimed to study the effect of Hepatitis B virus surface protein (HBsAg) on cholestatic liver disease and associated carcinogenesis in a mouse model combining both impairments. Hybrids of Abcb4-/- and HBsAg transgenic mice were bred on fibrosis susceptible background BALB/c. Liver injury, serum bile acid concentration, hepatic fibrosis, and carcinogenesis were enhanced by the combination of simultaneous damage in line with activation of c-Jun N-terminal kinase (JNK), proto-oncogene c-Jun, and Signal transducer and activator of transcription 3 (STAT3). Activation of Protein Kinase RNA-like Endoplasmic Reticulum Kinase (PERK) and Eukaryotic translation initiation factor 2A (eIF2a) indicated unfolded protein response (UPR) in HBsAg-expressing mice and even in Abcb4-/- without HBsAg-expression. CONCLUSION: Cholestasis-induced STAT3- and JNK-pathways may predispose HBsAg-associated tumorigenesis. Since STAT3- and JNK-activation are well characterized critical regulators for tumor promotion, the potentiation of their activation in hybrids suggests an additive mechanism enhancing tumor incidence

    High performance solar receiver-reactor for solar hydrogen generation

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    This paper reports on the numerical analysis of a volumetric solar receiver-reactor for hydrogen production, using the 2-step reduction–oxidation cycle. A detailed parametric sweep covering hundreds of various parameter combinations is performed for a large solar reactor, using a transient physical model. We generate performance maps which are currently cost prohibitive via experimental or high–fidelity simulation studies. The following performance metrics are evaluated: solar to fuel efficiency, hydrogen yield, conversion extent and specific hydrogen yield. We show that the relations between the different performance metrics are complex, leading to different optimal points depending on the metric pursued. The daily hydrogen yield for a single reactor varied between 0.89 kg for an absorber thickness of 30 mm, and up to 1.04 kg for a 60 mm thick receiver, with solar to fuel efficiency values of 3.84% and 3.81% respectively. For a case with 45 mm thick receiver, an intermediate hydrogen yield of 0.94 kg is calculated, while exhibiting the highest efficiency (4.05%). The efficiency can be further increased to 5.86% by using a simple heat recovery system, and reach an upper limit of 21.16% with a more sophisticated heat recovery method
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