4,022 research outputs found

    DRAWING DOWN ON THE VALUE OF A NON-FUNGIBLE TOKEN (NFT) AND ITS ASSOCIATED ASSET VIA SALE OR TRANSFER ON THE BLOCKCHAIN TO FUND AND OR PROVIDE CREDIT COLLATERAL ON A PURCHASE

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    The present disclosure relates to a method and system for drawing down on an NFT’s value to fund a purchase in real-time. The method comprises transmitting a purchase request to an NFT Application Programming Interface (API) 108 hosted on a payment server seeking an authorization to purchase goods/services using the value of the NFT. In response to the purchase request, the NFT API 108 holding the NFT may transfer, via sale on the blockchain the NFT’s ownership to the merchant to settle and approve the transaction. Alternatively, the NFT API 108 may sell a portion of the NFT to the market to convert the NFT to a fiat currency and process the transaction using the fiat currency. Alternatively, the NFT API 108 may sell a portion of the NFT to a financial institution which has bid the most competitive terms to provide a credit facility to the purchaser. The financial institution will hold this as collateral against the credit facility that is provided. Once the collateral has been received, the financial institution will provide the fiat currency required to process the transaction. Once the proportionate amount of the NFT has been sold to fund the purchase, ownership of the purchaser of the NFT is drawn down and the transaction is approved. Finally, the payment server sends an authorization to the merchant and transaction is completed

    Implantation of silicon dioxide-based nanocrystalline hydroxyapatite and pure phase beta-tricalciumphosphate bone substitute granules in caprine muscle tissue does not induce new bone formation

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    Background: Osteoinductive bone substitutes are defined by their ability to induce new bone formation even at heterotopic implantation sites. The present study was designed to analyze the potential osteoinductivity of two different bone substitute materials in caprine muscle tissue. Materials and methods: One gram each of either a porous beta-tricalcium phosphate (β-TCP) or an hydroxyapatite/silicon dioxide (HA/SiO2)-based nanocrystalline bone substitute material was implanted in several muscle pouches of goats. The biomaterials were explanted at 29, 91 and 181 days after implantation. Conventional histology and special histochemical stains were performed to detect osteoblast precursor cells as well as mineralized and unmineralized bone matrix. Results: Both materials underwent cellular degradation in which tartrate-resistant acid phosphatase (TRAP)-positive osteoclast-like cells and TRAP-negative multinucleated giant cells were involved. The ß-TCP was completely resorbed within the observation period, whereas some granules of the HA-groups were still detectable after 180 days. Neither osteoblasts, osteoblast precursor cells nor extracellular bone matrix were found within the implantation bed of any of the analyzed biomaterials at any of the observed time points. Conclusions: This study showed that ß-TCP underwent a faster degradation than the HA-based material. The lack of osteoinductivity for both materials might be due to their granular shape, as osteoinductivity in goat muscle has been mainly attributed to cylindrical or disc-shaped bone substitute materials. This hypothesis however requires further investigation to systematically analyze various materials with comparable characteristics in the same experimental setting

    Bayesian parameter estimation for characterising mobile ion vacancies in perovskite solar cells

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    To overcome the challenges associated with poor temporal stability of perovskite solar cells, methods are required that allow for fast iteration of fabrication and characterisation, such that optimal device performance and stability may be actively pursued. Currently, establishing the causes of underperformance is both complex and time-consuming, and optimisation of device fabrication thus inherently slow. Here, we present a means of computational device characterisation of mobile halide ion parameters from room temperature current-voltage (J-V) measurements only, requiring ∼2\sim 2 hours of computation on basic computing resources. With our approach, the physical parameters of the device may be reverse modelled from experimental J-V measurements. In a drift-diffusion model, the set of coupled drift-diffusion partial differential equations cannot be inverted explicitly, so a method for inverting the drift-diffusion simulation is required. We show how Bayesian Parameter Estimation (BPE) coupled with a drift-diffusion perovskite solar cell model can determine the extent to which device parameters affect performance measured by J-V characteristics. Our method is demonstrated by investigating the extent to which device performance is influenced by mobile halide ions for a specific fabricated device. The ion vacancy density N0N_0 and diffusion coefficient DID_I were found to be precisely characterised for both simulated and fabricated devices. This result opens up the possibility of pinpointing origins of degradation by finding which parameters most influence device J-V curves as the cell degrades

    Granulovirus PK-1 kinase activity relies on a side-to-side dimerization mode centered on the regulatory αC helix

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    The life cycle of Baculoviridae family insect viruses depends on the viral protein kinase, PK-1, to phosphorylate the regulatory protein, p6.9, to induce baculoviral genome release. Here, we report the crystal structure of Cydia pomenella granulovirus PK-1, which, owing to its likely ancestral origin among host cell AGC kinases, exhibits a eukaryotic protein kinase fold. PK-1 occurs as a rigid dimer, where an antiparallel arrangement of the αC helices at the dimer core stabilizes PK-1 in a closed, active conformation. Dimerization is facilitated by C-lobe:C-lobe and N-lobe:N-lobe interactions between protomers, including the domain-swapping of an N-terminal helix that crowns a contiguous β-sheet formed by the two N-lobes. PK-1 retains a dimeric conformation in solution, which is crucial for catalytic activity. Our studies raise the prospect that parallel, side-to-side dimeric arrangements that lock kinase domains in a catalytically-active conformation could function more broadly as a regulatory mechanism among eukaryotic protein kinases

    Growth and Crystallisation of Ferromagnetic and Antiferromagnetic Fe2+xVyAl Heusler Alloy Films

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    We investigated growth, annealing conditions and magnetic properties of the Heusler alloy Fe2+xVyAl by means of X-ray diffraction, magnetic hysteresis and exchange-bias measurements. Ferromagnetic Heusler alloy films were obtained by sputtering Fe2VAl and Fe3VAl targets and performing post-growth annealing. The characteristic (220) Heusler alloy peaks were seen in the X-ray diffraction measurements and corresponding ferromagnetic behaviours were observed. In addition, antiferromagnetic Heusler alloy films were deposited by employing Al pegs on Fe3VAl sputtering targets. The deposited films had elemental ratios close to the predicted Fe2.5V0.5Al phase, and a 16 Oe exchange-bias was measured in a Fe2.5V0.5Al/Co60Fe40 system at 100 K
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