Long term electricity storage by oxygen liquefaction and LNG oxy-combustion

The paper proposes an innovative scheme exploiting oxygen liquefaction as a means for storing excess electricity generation from renewable sources. Liquid oxygen is then used in an oxy-combustion process with LNG to generate electricity when renewable energy generation is below the demand. An equivalent round trip efficiency is defined to make it possible comparing the system performances with hybrid plants including conventional generation and storage. The proposed scheme exhibits very high equivalent round trip efficiency, giving the system operators the opportunity to integrate more and more renewable energy generation inside power systems. Liquefied carbon dioxide and water are byproducts of the process. The size of the plant and of the storage tanks needed for a 4 TWh yearly demand with a peak around 800 MW is compatible with state-of-the-art systems used for LNG storage in similar size gas power plants

Iron Binding in the Ferroxidase Site of Human Mitochondrial Ferritin

Ferritins are nanocage proteins that store iron ions in their central cavity as hydrated ferric oxide biominerals. In mammals, further the L (light) and H (heavy) chains constituting cytoplasmic maxi-ferritins, an additional type of ferritin has been identified, the mitochondrial ferritin (MTF). Human MTF (hMTF) is a functional homopolymeric H-like ferritin performing the ferroxidase activity in its ferroxidase site (FS), in which Fe(II) is oxidized to Fe(III) in the presence of dioxygen. To better investigate its ferroxidase properties, here we performed time-lapse X-ray crystallography analysis of hMTF, providing structural evidence of how iron ions interact with hMTF and of their binding to the FS. Transient iron binding sites, populating the pathway along the cage from the iron entry channel to the catalytic center, were also identified. Furthermore, our kinetic data at variable iron loads indicate that the catalytic iron oxidation reaction occurs via a diferric peroxo intermediate followed by the formation of ferric-oxo species, with significant differences with respect to human H-type ferritin

Different histologic patterns of cutaneous granulomas in systemic lymphoma

BACKGROUND: Patients with Hodgkin's and non-Hodgkin's lymphomas may develop non-infectious granulomas in both involved and uninvolved organs, but rarely in the skin. Cutaneous granulomas in the setting of a systemic lymphoma are of two types. The first type is characterized by granulomatous infiltrates admixed with neoplastic cells within specific skin lesions of malignant lymphomas. The second type consists of granulomatous skin processes that are non-specific manifestations of the underlying lymphoma. OBJECTIVE: To describe the variegate histologic patterns of cutaneous granulomatous reactions of the second type in patients with systemic lymphomas. METHODS: We describe three patients with systemic lymphomas who exhibited three different histologic patterns of cutaneous granulomatous lesions. RESULTS: The first patient had non-Hodgkin's lymphoma with cutaneous tuberculoid-type granuloma mimicking tuberculoid leprosy; the second patient had Hodgkin's lymphoma with palisaded, necrobiotic granuloma of granuloma annulare-type; and the third patient had non-Hodgkin's lymphoma with sarcoid-type granuloma. No evidence of the underlying systemic lymphoma was found in the cutaneous lesions involved by the granulomatous process. CONCLUSIONS: Cutaneous granulomas may be a non-specific sign of an underlying systemic lymphoma. Their histologic patterns are variegate and include sarcoid-type granuloma, palisaded and necrobiotic granuloma of granuloma annulare-type, and tuberculoid granuloma. In patients who present with non-infectious, granulomatous skin reactions in the absence of another sound explanation, the possibility of a systemic lymphoma should be considered

Direct detection of iron clusters in L ferritins through ESI-MS experiments

Human cytoplasmic ferritins are heteropolymers of H and L subunits containing a catalytic ferroxidase center and a nucleation site for iron biomineralization, respectively. Here, ESI-MS successfully detected labile metal-protein interactions revealing the formation of tetra- and octa-iron clusters bound to L subunits, as previously underscored by X-ray crystallography

Cost effective power-to-X plant using carbon dioxide from a geothermal plant to increase renewable energy penetration

In the framework of a scenario with an always increasing share of generation from variable renewable sources, the need for systems able to store energy or to convert the excess generation into useful goods is becoming of paramount importance. While several projects and pilot plants deal with direct energy storage or with the conversion of the excess generation into other energetic goods (hydrogen or methane) often overlooking economic considerations, this paper proposes a cost-effective approach in which liquified methane and oxygen are produced and sold on their specific markets, which represents one of the first profitable Power-to-X applications at current market values. The paper presents the completely new and never investigated before idea of coupling the plant with a freely available source of pure carbon dioxide from a geothermal unit, thus making it possible to produce synthetic methane to be liquefied, stored and then used in other sectors of the society. The carbon dioxide coming with the geothermal fluid is no longer released in the environment as it currently naturally happens even when not going through the geothermal facility. Detailed models of the main system components were created, and an optimization procedure was carried out. Interestingly, the revenues from the sale of liquefied oxygen are well above those coming from synthetic methane and turn the system profitable. With a proper operation planning, bidding on the electricity day-ahead-market, a large hydrogen storage system proved to be unnecessary. The results of the system optimization clearly show that this kind of systems, although conceived in a very favourable condition, can become profitable only if the energy storage function is coupled with the production of other goods services. Assuming an average electricity price of 52 €/MWh, the plant profitability is achieved for an LNG selling price of 0.45 €/kg and an LOx price around 0.30 €/kg. These figures will rapidly decrease in the near future as lower electricity prices are forecasted

Effects of hypobaric hypoxia exposure at high altitude on left ventricular twist in healthy subjects : data from HIGHCARE study on Mount Everest

Previous studies investigating the effect of hypoxia on left ventricle focused on its global function, an approach that may not detect a selective dysfunction of subendocardial layers that are most sensitive to an inadequate oxygen supply. In the HIGHCARE study, aimed at exploring the effects of high altitude hypoxia on multiple biological variables and their modulation by an angiotensin receptor blocker, we addressed the effects of hypobaric hypoxia on both systolic and diastolic left ventricular geometry and function, focusing on echocardiographic assessment of left ventricle twist to indirectly examine subendocardial left ventricular systolic function