Methane Reforming with H2S and Sulfur for Hydrogen Production: Thermodynamic Assessment

Nowadays, most ofthe hydrogen is obtained from fossil fuels. Atthe same time, the effort and resources dedicated to the developmentof sustainable hydrogen manufacturing processes are rapidly increasingto promote the energy transition toward renewable sources. In thisdirection, a potential source of hydrogen could be hydrogen sulfide,produced as a byproduct in several processes, and in particular inthe oil extraction and refinery operations. Methane reforming usingH(2)S has recently attracted much interest for its economicand environmental implications. Its conversion, in fact, providesa viable way for the elimination of a hazardous molecule, producinga high-added value product like hydrogen. At the same time, some ofthe still open key aspects of this process are the coke depositiondue to thermal pyrolysis of methane and the process endothermicity.In this work, the methane reforming with H2S by co-feedingsulfur is investigated through a detailed thermodynamic analysis asa way to alleviate the critical aspects highlighted for the process.A parametric analysis was conducted to assess the best thermodynamicconditions in terms of pressure, temperature, and feed composition.Changing the sulfur, H2S, and methane feed compositioncan enhance the system by improving the hydrogen production yield,reducing the carbon and sulfur deposition, increasing the H2S removal efficiency, and reducing the necessary thermal duty

Functionalized lactic acid macromonomers polycondensation

Please click Additional Files below to see the full abstrac

Structural analysis of MDM2 RING separates degradation from regulation of p53 transcription activity

MDM2–MDMX complexes bind the p53 tumor-suppressor protein, inhibiting p53's transcriptional activity and targeting p53 for proteasomal degradation. Inhibitors that disrupt binding between p53 and MDM2 efficiently activate a p53 response, but their use in the treatment of cancers that retain wild-type p53 may be limited by on-target toxicities due to p53 activation in normal tissue. Guided by a novel crystal structure of the MDM2–MDMX–E2(UbcH5B)–ubiquitin complex, we designed MDM2 mutants that prevent E2–ubiquitin binding without altering the RING-domain structure. These mutants lack MDM2's E3 activity but retain the ability to limit p53′s transcriptional activity and allow cell proliferation. Cells expressing these mutants respond more quickly to cellular stress than cells expressing wild-type MDM2, but basal p53 control is maintained. Targeting the MDM2 E3-ligase activity could therefore widen the therapeutic window of p53 activation in tumors

CHCHD2 inhibits apoptosis by interacting with Bcl-x L to regulate Bax activation

Mitochondrial outer membrane permeabilization (MOMP) is a critical control point during apoptosis that results in the release of pro-apoptotic mitochondrial contents such as cytochrome c. MOMP is largely controlled by Bcl-2 family proteins such as Bax, which under various apoptotic stresses becomes activated and oligomerizes on the outer mitochondrial membrane. Bax oligomerization helps promote the diffusion of the mitochondrial contents into the cytoplasm activating the caspase cascade. In turn, Bax is regulated primarily by anti-apoptotic Bcl-2 proteins including Bcl-xL, which was recently shown to prevent Bax from accumulating at the mitochondria. However, the exact mechanisms by which Bcl-xL regulates Bax and thereby MOMP remain partially understood. In this study, we show that the small CHCH-domain-containing protein CHCHD2 binds to Bcl-xL and inhibits the mitochondrial accumulation and oligomerization of Bax. Our data show that in response to apoptotic stimuli, mitochondrial CHCHD2 decreases prior to MOMP. Furthermore, when CHCHD2 is absent from the mitochondria, the ability of Bcl-xL to inhibit Bax activation and to prevent apoptosis is attenuated, which results in increases in Bax oligomerization, MOMP and apoptosis. Collectively, our findings establish CHCHD2, a previously uncharacterized small mitochondrial protein with no known homology to the Bcl-2 family, as one of the negative regulators of mitochondria-mediated apoptosis

Ribosomal protein-Mdm2-p53 pathway coordinates nutrient stress with lipid metabolism by regulating MCD and promoting fatty acid oxidation

Although progress has been made in the characterization of p53 in regulating metabolism, very little is known about the signaling pathways involved in this regulation in response to stress in vivo. Here we show that p53 controls hepatic fatty acid oxidation in mice in response to fasting. Disruption of ribosome protein (RP)-mouse double minute (Mdm)2 binding in Mdm2C305F mice results in fasting-induced hepatosteatosis. A full-dosage of p53 and an intact RP-Mdm2-p53 pathway are required for the induction of malonyl coA decarboxylase (MCD), a critical regulator of fatty acid oxidation. Thus, the RP-Mdm2-p53 pathway functions as a key regulator of hepatic lipid homeostasis in response to nutrient deprivation stress, a function that has implications in organismal survival and tumor suppression