The demand for liver transplantation (LT) exceeds supply, with rising waiting list mortality. Utilization of high‐risk organs is low and a substantial number of procured livers are discarded. We report the first series of five transplants with rejected livers following viability assessment by normothermic machine perfusion of the liver (NMP‐L). The evaluation protocol consisted of perfusate lactate, bile production, vascular flows, and liver appearance. All livers were exposed to a variable period of static cold storage prior to commencing NMP‐L. Four organs were recovered from donors after circulatory death and rejected due to prolonged donor warm ischemic times; one liver from a brain‐death donor was declined for high liver function tests (LFTs). The median (range) total graft preservation time was 798 (range 724–951) min. The transplant procedure was uneventful in every recipient, with immediate function in all grafts. The median in‐hospital stay was 10 (range 6–14) days. At present, all recipients are well, with normalized LFTs at median follow‐up of 7 (range 6–19) months. Viability assessment of high‐risk grafts using NMP‐L provides specific information on liver function and can permit their transplantation while minimizing the recipient risk of primary graft nonfunction. This novel approach may increase organ availability for LT.
Motivated by recent experimental measurements of the p$Ω^-$ correlation function and the concurrent theoretical efforts to describe the strong interaction among hadrons in the strangeness sector, we present a data-driven approach for fine tuning of a meson-exchanges potential for the p$Ω^-$ system. Using femtoscopy data from the ALICE and STAR collaborations, we constrain the strength of the interaction, encoded in the tunable short-range parameter introduced in the potential. The resulting model provides a good description of the measured correlation functions and favors the existence of a bound state in the \({}^5S_2\) channel with a binding energy of approximately \(0.5\,\mathrm{MeV}\). The role of the \({}^3S_1\) channel, however, remains poorly constrained due to the absence of an accurate model accounting for its inelastic contributions.
Study of radiative $α$ capture on $^{12}$C, $^{12}$C($α$,$γ$)$^{16}$O, in cluster effective field theory (EFT) is reviewed. A low energy EFT for $^{12}$C($α$,$γ$)$^{16}$O at the Gamow-peak energy, $E_G=0.3$~MeV, is constructed, and the theory is first applied to the study of elastic $α$-$^{12}$C scattering at low energies. The effective range parameters are fitted to the precise phase shift data of the elastic scattering and the astrophysical $S_{E1}$ factor of the $E1$ transition of $^{12}$C($α$,$γ$)$^{16}$O at $E_G$ is estimated. For the study of the $E2$ transition of $^{12}$C($α$,$γ$)$^{16}$O, we discuss a difficulty to determine the asymptotic normalization coefficient (ANC) of the subthreshold $2_1^+$ state of $^{16}$O from the elastic scattering data, and demonstrate the difficulty with the estimate of the astrophysical $S_{E2}$ factor of $^{12}$C($α$,$γ$)$^{16}$O at $E_G$. We discuss the uncertainty in the estimate of the $S$ factors at $E_G$ in the present approach.
The objective of this study is to simulate shielding effectiveness against galactic cosmic rays, focusing on secondary neutrons. The simulation uses a combination of aluminum and poly-ethylene materials. A Monte Carlo simulation was conducted, with the particle and heavy ion transport code system - PHITS. The shielding effectiveness of aluminum and polyethylene was compared. The flux spectra of secondary emissions from the rear surface of the slab shielding were computed. Results indicate that secondary neutrons are mainly generated when galactic cosmic ray protons interact with shielding material. The proposed layered configuration suggests that placing the polyethylene layer on the inner side of the shielding structure significantly improves the overall performance of aluminum. Polyethylene efficiently moderates and reduces secondary neutrons. This improvement in shielding contributes meaningfully to the protection of astronauts and onboard electronic equipment during long-duration deep space missions , where galactic radiation is more intense and prolonged.
This study presents neutronic analyses of a small modular reactor utilizing transuranium and thorium. Two different fuel cases are considered in the analyses as the transuranium extracted from PWR-MOX spent fuel (a form of a mixture of minor actinide and Pu isotopes) (Case A) and 4.5 % enriched UO2 with ThO 2(the form of separate fuel rods) (Case B). The total power of the considered small modular reactor containing 69 assemblies is 450 MW thermal. In both fuel cases, the time-dependent critical burnup calculations are carried out by using MCNPX 2.7 code until their effective neutron multiplication factors decrease to 0.99. The calculations bring out that the small modular reactor can operate for quite a long time without refueling and that a new fuel with a richness of 1.05 % can be obtained from ThO as well 2 as energy production.
Smart contracts are self-executing digital transactions using decentralized cryptographic mechanisms for enforcement. They were theorized more than twenty years ago, but the recent development of Bitcoin and blockchain technologies has rekindled excitement about their potential among technologists and industry. Startup companies and major enterprises alike are now developing smart contract solutions for an array of markets, purporting to offer a digital bypass around traditional contract law. For legal scholars, smart contracts pose a significant question: Can smart contracts offer a superior solution to the problem that contract law addresses? In this article, we aim to understand both the potential and the limitations of smart contracts. We conclude that smart contracts offer novel possibilities, may significantly alter the commercial world, and will demand new legal responses. But smart contracts will not displace contract law. Understanding why not brings into focus the essential role of contract law as a remedial institution. In this way, smart contracts actually can illuminate the role of contract law more than they can obviate it.
Vladimir Kondratjev, Vasily Litvinsky, Serhii Pohuliai
The results of engineering an intelligent preamplifier for high purity germanium gamma-detectors are presented. An intelligent preamplifier is a low-noise, high speed resistive feedback charge-sensitive preamplifier with a built-in microcontroller and additional units that enable control of preamplifier and detector parameters. It also allows the performance managing of the internal testing pulser, sensor of liquid nitrogen level in a Dewar, humidity, pressure and temperature sensors in a sealed preamplifier section. Intelligent preamplifier operation, set-up, and parameter measurements are controlled by a software.
Significance Transthyretin (TTR) cardiac amyloidosis is characterized by the deposition of TTR amyloid fibrils in the heart. No therapy is currently available for wild-type cardiac amyloidosis. Hereditary cases are treated by liver transplantation, a crude form of gene therapy which replaces amyloidogenic mutant TTR by the more stable wild-type form, with the goal of halting further deposition and disease progression. However, wild-type TTR continues to deposit in the heart of many patients after the procedure. Until now, seeding of TTR fibril formation has not been demonstrated in vitro. We show that patient-extracted cardiac fibrils can seed both wild-type and mutant TTR fibril formation in vitro. This process can be inhibited by structure-based peptide inhibitors, thereby providing an alternative approach to therapy. Each of the 30 human amyloid diseases is associated with the aggregation of a particular precursor protein into amyloid fibrils. In transthyretin amyloidosis (ATTR), mutant or wild-type forms of the serum carrier protein transthyretin (TTR), synthesized and secreted by the liver, convert to amyloid fibrils deposited in the heart and other organs. The current standard of care for hereditary ATTR is liver transplantation, which replaces the mutant TTR gene with the wild-type gene. However, the procedure is often followed by cardiac deposition of wild-type TTR secreted by the new liver. Here we find that amyloid fibrils extracted from autopsied and explanted hearts of ATTR patients robustly seed wild-type TTR into amyloid fibrils in vitro. Cardiac-derived ATTR seeds can accelerate fibril formation of wild-type and monomeric TTR at acidic pH and under physiological conditions, respectively. We show that this seeding is inhibited by peptides designed to complement structures of TTR fibrils. These inhibitors cap fibril growth, suggesting an approach for halting progression of ATTR.
Sumit Basu, Sanchari Thakur, Tapan K. Nayak
et al.
Multiplicity and pseudorapidity ($η$) density ($dN_{\rm ch}/dη$) distributions of charged hadrons provide key information towards understanding the particle production mechanisms and initial conditions of high-energy heavy-ion collisions. However, detector constraints limit the $η$-range across which charged particle measurements can be carried out. Extrapolating the measured distributions to large $η$-range by parameterizing measured distributions and by using calculations from event generators, we characterize the production of charged particles over the full kinematic range. In the present study, we use three different ans$\ddot{\mathrm a}$tze to obtain quantitative descriptions of the shape of pseudorapidity distributions of charged hadrons produced in pp, p-A, and A-A collisions for beam energies ($\sqrt{s_{\rm NN}}$) ranging from a few GeV to a few TeV corresponding to RHIC and LHC energies. We study the limiting fragmentation behavior in these collisions and report evidence for participant-scaling violations in high-energy collisions at the TeV scale. We additionally examine measured pseudorapidity distributions to constrain models describing initial conditions of particle production. We predict the centrality dependence of charged particle multiplicity distributions at FAIR and NICA energies and give an estimation of charged particle multiplicity at $η=0$ for the proposed HE-LHC and FCC energies.
The quark-gluon plasma produced by collisions between ultra-relativistic heavy nuclei is well described in the language of hydrodynamics. Non-central collisions are characterized by very large angular momentum, which in a fluid system manifests as flow vorticity. This rotational structure can lead to a spin polarization of the hadrons that eventually emerge from the plasma, providing experimental access to flow substructure at unprecedented detail. Recently, first observations of $Λ$ hyperon polarization along the direction of collisional angular momentum have been reported. These measurements are in broad agreement with hydrodynamic and transport-based calculations and reveal that the QGP is the most vortical fluid ever observed. However, there remain important tensions between theory and observation which might be fundamental in nature. In the relatively mature field of heavy ion physics, the discovery of global hyperon polarization and three-dimensional simulations of the collision have opened an entirely new direction of research. We discuss the current status of this rapidly developing area and directions for future research.
Target 8 of the Global Strategy for Plant Conservation calls for ‘at least 75 per cent of threatened plant species in ex situ collections, preferably in the country of origin, and at least 20 per cent available for recovery and restoration programmes by 2020’. Botanic gardens make a significant contribution to ex situ conservation of wild species with more than a third of plant species represented in botanic gardens collections. These collections are a combination of living collection and seed banked material. Seed banking can provide an efficient form of conservation for wild plant genetic diversity. Information from Botanic Gardens Conservation International's (BGCI) databases (GardenSearch, PlantSearch, ThreatSearch and GlobalTreeSearch) has been analysed as well as survey data to report on global, regional and national seed banking trends. Information from BGCI's databases indicates that there are at least 350 seed banking botanic gardens in 74 countries. In total 56,987 taxa have been banked including more than 9000 taxa that are threatened with extinction. 6881 tree species are stored in ex situ seed bank collections. More than half (3562) of these tree species are single country endemics and represent species from more than 166 countries. This study suggests that institutions are increasingly conserving plant species via seed banking. However the majority of species in collections that have a conservation assessment are not threatened with extinction. This disjunction between species that are threatened and those conserved in seed banks needs to be addressed. Data from BGCI's databases can be used to enable prioritisation of threatened plant species for collection and conservation in seed banks. Further recommendations for botanic gardens involved in seed conservation are presented.
Lung transplantation is a life-saving treatment for patients with end stage lung disease. The imbalance between lung graft supply and recipients has been a serious issue and barrier to successful lung transplantation. Ex vivo lung perfusion is a strategy wherein lungs are perfused and ventilated outside of the body. This technology has emerged as a safe preservation method that also enables the reassessment and reconditioning of marginal lung grafts. Ex vivo lung perfusion has successfully expanded the donor pool and led to greater lung transplant activity worldwide. Furthermore, ex vivo lung perfusion can be used as a platform for advanced diagnostics that enable specific targeted or personalized treatments that can be developed along a bench to bedside pathway leading to safe ex vivo intervention. Recent findings have shown that ex vivo lung perfusion could significantly and safely extend the preservation period, which enables transplant programs further optimization of the logistics around transplantation surgeries, and create a new paradigm whereby donor lungs are assessed at a centralized ex vivo lung perfusion center prior to delivery to a transplant clinic in need. The introduction of ex vivo lung perfusion to clinical lung transplantation has been a major step in the evolution and practice of lung transplantation.