Smart contracts are applications that execute on blockchains. Today they manage billions of dollars in value and motivate visionary plans for pervasive blockchain deployment. While smart contracts inherit the availability and other security assurances of blockchains, however, they are impeded by blockchains' lack of confidentiality and poor performance.We present Ekiden, a system that addresses these critical gaps by combining blockchains with Trusted Execution Environments (TEEs). Ekiden leverages a novel architecture that separates consensus from execution, enabling efficient TEE-backed confidentiality-preserving smart contracts and high scalability. Our prototype (with Tendermint as the consensus layer) achieves example performance of 600x more throughput and 400x less latency at 1000x less cost than the Ethereum mainnet.Another contribution of this paper is that we systematically identify and treat the pitfalls arising from harmonizing TEEs and blockchains. Treated separately, both TEEs and blockchains provide powerful guarantees, but hybridized, though, they engender new attacks. For example, in naïve designs, privacy in TEE-backed contracts can be jeopardized by forgery of blocks, a seemingly unrelated attack vector. We believe the insights learned from Ekiden will prove to be of broad importance in hybridized TEE-blockchain systems.

Objective-There are limited data comparing hepatic phenotype among hemochromatosis patients with different HFE genotypes. The goal of this study was to compare hepatic histopathologic features and hepatic iron concentration (HIC) among patients with phenotypic hemochromatosis and different HFE genotypes.Methods-We studied 182 U.S. patients with phenotypic hemochromatosis. Degree of hepatic fibrosis, pattern of iron deposition, presence of steatosis or necroinflammation, and HIC were compared among different HFE genotypes.Results-C282Y/H63D compound heterozygotes and patients with HFE genotypes other than C282Y/C282Y were more likely to have stainable Kupffer cell iron (31.1% vs 9.5%; p=0.02), portal or lobular inflammation (28.9% vs 15.6%; p=0.03) and steatosis (33.3% vs 10.2%; p<0.01) on liver biopsy than C282Y homozygotes. Mean log 10 HIC (p<0.05) and log 10 ferritin (p<0.05) were higher among C282Y homozygotes than in patients with other HFE genotypes. In a logistic regression analysis using age, gender, HFE genotype, log 10 ferritin, and log 10 HIC as independent variables, log 10 SF (p = 0.0008), male sex (p = 0.0086), and log 10 HIC (p=0.047), but not HFE genotype (p = 0.0554) were independently associated with presence or absence of advanced hepatic fibrosis. Conclusions-C282Y/H63Dcompound heterozygotes and other non-C282Y homozygotes who express the hepatic hemochromatosis phenotype frequently have evidence of steatosis or chronic hepatitis and lower body iron stores than C282Y homozygotes. These data suggest that presence of concomitant liver disease may explain expression of the hemochromatosis phenotype among non-C282Y homozygotes. Increased age, HIC and ferritin are associated with advanced hepatic fibrosis, regardless of HFE genotype.

No abstract

No abstract