Masks thermal degradation as an alternative of waste valorization on the COVID-19 pandemic: A kinetic study.

The COVID-19 pandemic generated a new dynamic around waste management. Personal protective equipment such as masks, gloves, and face shields were essential to prevent the spread of the disease. However, despite the increase in waste, no technical alternatives were foreseen for the recovery of these wastes, which are made up of materials that can be valued for energy recovery. It is essential to design processes such as waste to energy to promote the circular economy. Therefore, techniques such as pyrolysis and thermal oxidative decomposition of waste materials need to be studied and scaled up, for which kinetic models and thermodynamic parameters are required to allow the design of this reaction equipment. This work develops kinetic models of the thermal degradation process by pyrolysis as an alternative for energy recovery of used masks generated by the COVID-19 pandemic. The wasted masks were isolated for 72 h for virus inactivation and characterized by FTIR-ATR spectroscopy, elemental analysis, and determinate the higher calorific value (HCV). The composition of the wasted masks included polypropylene, polyethylene terephthalate, nylon, and spandex, with higher calorific values than traditional fuels. For this reason, they are susceptible to value as an energetic material. Thermal degradation was performed by thermogravimetric analysis at different heating rates in N2 atmosphere. The gases produced were characterized by gas chromatography and mass spectrometry. The kinetic model was based on the mass loss of the masks on the thermal degradation, then calculated activation energies, reaction orders, pre-exponential factors, and thermodynamic parameters. Kinetics models such as Coats and Redfern, Horowitz and Metzger, Kissinger-Akahira-Sunose were studied to find the best-fit models between the experimental and calculated data. The kinetic and thermodynamic parameters of the thermal degradation processes demonstrated the feasibility and high potential of recovery of these residues with conversions higher than 89.26% and obtaining long-chain branched hydrocarbons, cyclic hydrocarbons, and CO2 as products.

Introducing or removing heparan sulfate binding sites does not alter brain uptake of the blood-brain barrier shuttle scFv8D3.

The blood-brain barrier (BBB) greatly limits the delivery of protein-based drugs into the brain and is a major obstacle for the treatment of brain disorders. Targeting the transferrin receptor (TfR) is a strategy for transporting protein-based drugs into the brain, which can be utilized by using TfR-binding BBB transporters, such as the TfR-binding antibody 8D3. In this current study, we investigated if binding to heparan sulfate (HS) contributes to the brain uptake of a single chain fragment variable of 8D3 (scFv8D3). We designed and produced a scFv8D3 mutant, engineered with additional HS binding sites, HS(+)scFv8D3, to assess whether increased HS binding would improve brain uptake. Additionally, a mutant with a reduced number of HS binding sites, HS(-)scFv8D3, was also engineered to see if reducing the HS binding sites could also affect brain uptake. Heparin column chromatography showed that only the HS(+)scFv8D3 mutant bound HS in the experimental conditions. Ex vivo results showed that the brain uptake was unaffected by the introduction or removal of HS binding sites, which indicates that scFv8D3 is not dependent on the HS binding sites for brain uptake. Conversely, introducing HS binding sites to scFv8D3 decreased its renal excretion while removing them had the opposite effect.

Brain integrity is altered by hepatic APOE ε4 in humanized-liver mice.

Liver-generated plasma apolipoprotein E (apoE) does not enter the brain but nonetheless correlates with Alzheimer's disease (AD) risk and AD biomarker levels. Carriers of APOEε4, the strongest genetic AD risk factor, exhibit lower plasma apoE and altered brain integrity already at mid-life versus non-APOEε4 carriers. Whether altered plasma liver-derived apoE or specifically an APOEε4 liver phenotype promotes neurodegeneration is unknown. Here we investigated the brains of Fah-/-, Rag2-/-, Il2rg-/- mice on the Non-Obese Diabetic (NOD) background (FRGN) with humanized-livers of an AD risk-associated APOE ε4/ε4 versus an APOE ε2/ε3 genotype. Reduced endogenous mouse apoE levels in the brains of APOE ε4/ε4 liver mice were accompanied by various changes in markers of synaptic integrity, neuroinflammation and insulin signaling. Plasma apoE4 levels were associated with unfavorable changes in several of the assessed markers. These results propose a previously unexplored role of the liver in the APOEε4-associated risk of neurodegenerative disease.

Energy Return on Investment (EROI) and Life Cycle Analysis (LCA) of biofuels in Ecuador.

In Ecuador, the net energy contribution of biofuels is unknown or unnoticed. To address this issue, we determined the Energy Return on Investment (EROI) for bioethanol and biodiesel. The selection of raw materials relied on their productive capacity, export and import records, and historical yields. Consequently, the scope included three raw materials for ethanol (sugar cane, corn, and forest residues) and four for biodiesel (African palm, pinion, bovine fat, and swine fat). Using a method based on the Life Cycle Analysis (LCA) of each biofuel, we assessed the entire production chain through statistical processing of primary and secondary information. Then we calculated the calorific values in the laboratory, compared energy inputs/outputs, and finally obtained the energetic returns. EROIs for bioethanol were: 1.797 for sugarcane, 1.040 for corn, and 0.739 for wood. The results for biodiesel were: 3.052 for African palm, 2.743 for pinion, 2.187 for bovine fat, and 2.891 for swine fat. These values suggest feasibility only for sugarcane in the case of ethanol. In contrast, biodiesel has better prospects because all the feedstocks analyzed had EROIs higher than two. Nevertheless, biodiesel is not available for trading in Ecuador because energy policy has overlooked systems based on higher energy return. Future studies should consider more comprehensive variables such as climate change, land use, and water management.

Force-Profile Analysis of the Cotranslational Folding of HemK and Filamin Domains: Comparison of Biochemical and Biophysical Folding Assays.

We have characterized the cotranslational folding of two small protein domains of different folds-the α-helical N-terminal domain of HemK and the ß-rich FLN5 filamin domain-by measuring the force that the folding protein exerts on the nascent chain when located in different parts of the ribosome exit tunnel (force-profile analysis, or FPA), allowing us to compare FPA to three other techniques currently used to study cotranslational folding: real-time FRET, photoinduced electron transfer, and NMR. We find that FPA identifies the same cotranslational folding transitions as do the other methods, and that these techniques therefore reflect the same basic process of cotranslational folding in similar ways.