1,721,145 research outputs found
LA BANDA DEI CHIMICI
No full textSi può accendere una lampadina con un limone?
E creare un piccolo vulcano usando l'aceto?
Tra molecole parlanti e atomi che camminano, Emilio e la sua banda vivono curiose avventure nel mondo della chimica, scoprono i misteri di alcuni fenomeni scientifici e si divertono a sperimentare all'ombra degli alberi di un parco. Ma un imprevisto rovina la crescita di alcuni cristalli e la banda di amici deve vedersela con un paio di intrusi..
Genetic Engineering of Microalgae to Increase Biodiesel Production
No full textCarbon dioxide concentrations in the atmosphere are continuously increasing. The growth is strongly correlated to climate change. Lowering anthropic CO2 emissions is a crucial step towards a more sustainable management of planet resources and CCU (Carbon Capture and Utilisation) technologies performed with microalgae can be a feasible strategy. Microalgae can use CO2 of flue gasses to produce valuable chemical compounds, like lipids that can be successively converted into biodiesel. In order to make biodiesel an economically profitable material, genetical engineering of algal metabolic pathways, such as those involved in lipid production, lipid degradation, carbon fixation and photosynthesis, can be used. Moreover, engineering microalgae, to guarantee easier harvesting and product extraction, can further decrease biodiesel price. This paper presents different methodologies to genetically engineer microalgae and different targets to guarantee increased lipid accumulation and thus biodiesel production
Bioactive Derivatives from Algae: Properties and Applications in Pharmaceuticals
Full text linkUsing algae metabolites is considered a current and innovative topic of interest. Among the various applying sectors such as food, manufacturing, and environment, these organisms are also characterized by a high therapeutic potential. The influence of biotic and abiotic factors allows the production of different bioactive compounds, such as carbohydrates, polyphenols, proteins, vitamins, sterols, fatty acids and many others. The algal biomass is investigated to discover and develop new possible therapies and nowadays different properties have been determined, like antioxidant, antiviral, antimicrobial, anti-inflammatory, antidiabetic. Typical examples include the application of algae in diabetes mellitus, which is a disease that is continually spreading throughout Europe and the world. Numerous trials are currently underway to develop innovative and effective treatments, as well as several algae are being investigated in order to gain a deeper understanding of this pathology. In recent studies it has been demonstrated that metabolites such as polyphenols, polysaccharides and pigments, by their inhibitory activity, are capable of reducing blood glucose levels and increasing the amount of insulin
Hydrogen production from biomass
No full textThe demand for hydrogen is expected to grow rapidly in the coming years, especially for environmental reasons such as achieving decarbonization and reducing greenhouse gas emissions. Currently, most hydrogen is produced from fossil fuels, which is not sustainable. Alternative sources and methods for hydrogen production are required, and one of the most promising sources is biomass. Thermochemical and biological methods are the two main categories for hydrogen production from biomass. Thermochemical methods include gasification and pyrolysis: in these processes the raw material is treated at high temperatures to produce hydrogen together with solids, liquids and other gases. Biological methods are mainly bio-photolysis, photo fermentation, dark fermentation and microbial electrolysis cell. The biological method utilizes microorganisms to convert water and organic substrates into hydrogen: hydrogenase and nitrogenase are key enzymes in these processes
First time-resolved EPR observation of Nafion photochemistry
No full textTime-resolved EPR spectra of UV-irradiated Nafion reveal the formation of spin-polarized excited triplet states and allow the detection of photoinduced triplet–triplet energy transfer processes through hydrogen bonds between water and sulfonic acid groups
Paramagnetic C60 derivatives with one and more unpaired electrons: Spin polarization and photoelectron transfer
No full textFullerene C60 derivatives covalently linked to a nitroxide radical are studied by Time Resolved EPR. The interaction
between radical and triplet or singlet excitation,lo calized on the fullerene moiety,gives rise to spin polarization of the
radical EPR signal. The quartet state of the Radical Triplet Pair (RTP) is also observed by EPR. Electron transfer
involving the excited fullerene triplet is studied through the effects on the spin polarization pattern
Electrical conductivity and chemical equilibria of the phosphoric acid – water system at HT-PEM fuel cells relevant condition
No full textHigh temperature polymer electrolyte membrane (HT-PEM) fuel cells typically work at 120-200°C and are mainly based on phosphoric acid (PA) swollen basic polymer membranes like phosphoric acid doped polybenzimidazole. An overview can be found in [1-7]. Although PA is a widely used material even outside the field of electrochemical transformers, only little is known about the thermodynamical but also physical properties at temperatures above 100°C. Especially the correlation between different parameters provided from different sources in literature is often demanding due to different experimental approaches.
In this work, an alternative approach is used simulating directly the conditions inside an operational HT-PEM. The obtained physical and thermodynamic data are critically compared to results from other laboratories
Biotechnology to investigate the microbial community responsible of biogas production from biomass
No full textBiotechnology represents a new point of view on the organic matter and its purposes. The biotechnological approach consists in the exploitation of living organisms or biological systems for specific intents, such as the production of metabolites or the modification and improvement of processes. The organic waste, used for the biogas production, contains complex microbial consortia. In the humid and airless environment, typical of the anaerobic digestion, the organic matter’s degradation is catalysed by those microbes that, by their nature, are already present in the biomasses used in the implant, constituting the core of methane production. For this reason in the past few years, many researches have been accomplished to understand which are the central microbial species and their relationships, with the aim of optimizing the energetic efficiency and reduce costs of the process itself. This contribute presents a panoramic of the current problematics, confronting them and commenting, pagroposing new possible strategies with the aim of furnish guide lines to enhance the biogas production
The sign of the exchange interaction between triplet excited fullerene and nitroxide free radicals
No full textThe sign of the exchange interaction J in a series of radical triplet pairs (RTPs), formed
by a nitroxide free radical and a triplet excited fullerene, has been determined from the spin polarization
of time-resolved electron paramagnetic resonance spectra. Radical and fullerene are linked together
by covalent bonds in different geometries. It is shown that the sign of J depends on the overlap
between the orbital of nitroxide unpaired electron and the LUMO of fullerene, which is singly
occupied in the excited triplet state. When the overlap does not vanish, a negative contribution to J
arises from the admixing of a charge transfer structure in the wave function of the excited doublet
state D of the RTP, which does not take place in the excited quartet state Q. The mixing of D*
and Q' states lowers the energy of the former spin state and gives antiferromagnetic coupling
Mycelium-Based Leather: A Review on Post-Processing Treatments and Material Enhancements
Full text linkTextile and fashion industry is one of the most polluting industrial sectors in the world, responsible for high greenhouse gas emissions and water contamination. Leather tanning is a non-eco-friendly process, which consumes large amounts of water and energy while potentially releasing heavy metals and toxic compounds into the environment. Although synthetic leather offers simplified production processes, it is derived from fossil fuels and is non-biodegradable, raising further environmental concerns. Filamentous fungi, with their ability to form leather-like biomaterials through controlled fermentation, represent a promising and sustainable alternative. Critical parameters like fungi species selection, nutrient composition, growth conditions and treatment techniques are analysed. Distinct types of post-processing treatments that can enhance mechanical performance, durability, and water resistance are discussed highlighting the potential of mycelium-based materials as a sustainable alternative to conventional leather
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