A Transform for NIZK Almost as Efficient and General as the Fiat-Shamir Transform Without Programmable Random Oracles

The Fiat-Shamir (FS) transform is a popular technique for obtaining practical zero-knowledge argument systems. The FS transform uses a hash function to generate, without any further overhead, non-interactive zero-knowledge (NIZK) argument systems from public-coin honest-verifier zero-knowledge (public-coin HVZK) proof systems. In the proof of zero knowledge, the hash function is modeled as a programmable random oracle (PRO). In TCC 2015, Lindell embarked on the challenging task of obtaining a similar transform with improved heuristic security. Lindell showed that, for several interesting and practical languages, there exists an efficient transform in the non-programmable random oracle (NPRO) model that also uses a common reference string (CRS). A major contribution of Lindell’s transform is that zero knowledge is proved without random oracles and this is an important step towards achieving efficient NIZK arguments in the CRS model without random oracles. In this work, we analyze the efficiency and generality of Lindell’s transform and notice a significant gap when compared with the FS transform. We then propose a new transform that aims at filling this gap. Indeed our transform is almost as efficient as the FS transform and can be applied to a broad class of public-coin HVZK proof systems. Our transform requires a CRS and an NPRO in the proof of soundness, similarly to Lindell’s transform

Improved OR-Composition of Sigma-Protocols

In [CDS94] Cramer, Damg̊ard and Schoenmakers (CDS) devise an OR-composition technique for Σ-protocols that allows to construct highly-efficient proofs for compound statements. Since then, such technique has found countless applications as building block for designing efficient protocols. Unfortunately, the CDS OR-composition technique works only if both statements are fixed before the proof starts. This limitation restricts its usability in those protocols where the theorems to be proved are defined at different stages of the protocol, but, in order to save rounds of communication, the proof must start even if not all theorems are available. Many round-optimal protocols ([KO04, DPV04, YZ07, SV12]) crucially need such property to achieve round-optimality, and, due to the inapplicability of CDS’s technique, are currently implemented using proof systems that requires expensive NP reductions, but that allow the proof to start even if no statement is defined (a.k.a., LS proofs from Lapidot-Shamir [LS90]). In this paper we show an improved OR-composition technique for Σ-protocols, that requires only one statement to be fixed when the proof starts, while the other statement can be define

Progress in cardiovascular anastomoses: will the vascular join replace Carrel's technique?

Background: Vascular reconstructions are becoming challenging due to the comorbidity of the aging population and since the introduction of minimally invasive approaches. Many sutureless anastomosis devices have been designed to facilitate the cardiovascular surgeon's work and the vascular join (VJ) is one of these. We designed an animal study to assess its reliability and long-term efficacy. Methods: VJ allows the construction of end-to-end and end-to-side anastomoses. It consists of two metallic crowns fixed to the extremity of the two conduits so that vessel edges are joined layer by layer. There is no foreign material exposed to blood. In adult sheep both carotid arteries were prepared and severed. End-to-end anastomoses were performed using the VJ device on one side and the classical running suture technique on the other side. Animals were followed-up with Duplex-scan every 3 months and sacrificed after 12 months. Histopathological analysis was carried out. Results: In 20 animals all 22 sutureless anastomoses were successfully completed in less than 2min versus 6±3min for running suture. Duplex showed the occlusion of three controls and one sutureless anastomosis. Two controls and one sutureless had stenosis >50%. Histology showed very thin layer of myointimal hyperplasia (50±10μm) in the sutureless group versus 300±27μm in the control. No significant inflammatory reaction was detected. Conclusions: VJ provides edge-to-edge vascular repair that can be considered the most physiological way to restore vessel continuity. For the first time, in healthy sheep, an anastomotic device provided better results than suture techniqu

The possible role of the ubiquitin proteasome system in the development of atherosclerosis in diabetes

We have reviewed the impact of the ubiquitin proteasome system (UPS) on atherosclerosis progression of diabetic patients. A puzzle of many pieces of evidence suggests that UPS, in addition to its role in the removal of damaged proteins, is involved in a number of biological processes including inflammation, proliferation and apoptosis, all of which constitute important characteristics of atherosclerosis. From what can be gathered from the very few studies on the UPS in diabetic cardiovascular diseases published so far, the system seems to be functionally active to a different extent in the initiation, progression, and complication stage of atherosclerosis in the diabetic people. Further evidence for this theory, however, has to be given, for instance by specifically targeted antagonism of the UPS. Nonetheless, this hypothesis may help us understand why diverse therapeutic interventions, which have in common the ability to reduce ubiquitin-proteasome activity, can impede or delay the onset of diabetes and cardiovascular diseases (CVD)

About the shallow resistivity structure of Vesuvius volcano

Magnetotelluric (MT) soundings performed in the past in the volcanic area of Mt. Vesuvius by two independent research groups showed in the same places MT apparent resistivity curves with very similar shape, but statically shifted by one order of magnitude, at least. To try to resolve this ambiguity new controlled source audio-magnetotelluric (CSAMT) measurements have been carried out in the same MT sites. The interpretation of the CSAMT dataset, combined with that of two shallow dipole-dipole geoelectrical resistivity tomographies previously carried out in the area have allowed a reliable electrical structure to be recovered down to a few km of depth, which will next be used for a best constrained re-interpretation of the deep MT soundings

Brief episodes of silent atrial fibrillation predict clinical vascular brain disease in type 2 diabetic patients

ObjectivesThis study evaluated whether subclinical episodes of atrial fibrillation (AF) were associated with an increased risk of silent cerebral infarct (SCI) and stroke in diabetic patients younger than 60 years who did not have other clinical evidence of AF and cerebrovascular disease at baseline.BackgroundIn type 2 diabetic patients, one-fourth of strokes are of unknown cause, and subclinical episodes of AF may be a common etiologic factor.MethodsA total of 464 type 2 diabetic patients younger than 60 years were included in a longitudinal observational study and matched to patients without diabetes. Patients underwent 48-h electrocardiographic Holter monitoring quarterly to detect brief subclinical episodes of AF (duration of AF <48 h) and were followed up for 37 months. The outcomes were SCI, assessed by magnetic resonance imaging of the brain, and stroke events during the follow-up period.ResultsThe prevalence of subclinical episodes of AF was significantly greater among patients with diabetes compared with matched healthy subjects (11% vs. 1.6%, p < 0.0001). During an average duration of 37 months, 43 stroke events occurred in the diabetic population and no events occurred in healthy subjects. Diabetic patients with silent episodes of AF (n = 176) had a higher baseline prevalence of SCI (61% vs. 29%; p < 0.01) and a higher number of stroke events (17.3% vs. 5.9%; p < 0.01) during the follow-up period than the other patients (n = 288). An episode of silent AF was an independent determinant of SCI (odds ratio: 4.441; p < 0.001; confidence interval: 2.42 to 8.16) and an independent predictor of the occurrence of stroke in diabetic patients (hazard ratio: 4.6; p < 0.01; confidence interval: 2.7 to 9.1).ConclusionsSubclinical episodes of AF occurred frequently in type 2 diabetic patients and were associated with a significantly increased risk of SCI and stroke

Actin remodeling driven by circLIMA1: sperm cell as an intriguing cellular model

CircRNA cargo in spermatozoa (SPZ) participates in setting cell quality, in terms of morphology and motility. Cannabinoid receptor CB1 activity is correlated with a proper spermatogenesis and epididymal sperm maturation. Despite CB1 promotes endogenous skill to circularize mRNAs in SPZ, few notions are reported regarding the functional link between endocannabinoids and spermatic circRNA cargo. In CB1 knock-out male mice, we performed a complete dataset of spermatic circRNA content by microarray strategy. Differentially expressed (DE)-circRNAs, as a function of genotype, were identified. Within DE-circRNAs, we focused the attention on circLIMA1, as putative actin-cytoskeleton architecture regulator. The validation of circLIMA1 dependent-competitive endogenous RNA (ceRNA) network (ceRNET) in in vitro cell line confirmed its activity in the regulation of the cytoskeletal actin. Interestingly, a dynamic actin regulation in SPZ nuclei was found during their epididymal maturation. In this scenario, we showed for the first time an intriguing sperm nuclear actin remodeling, regulated via a ceRNET-independent pathway, consisting in the nuclear shuttling of circLIMA1-QKI interactome and downstream in Gelsolin regulation. In particular, the increased levels of circLIMA1 in CB1 knock-out SPZ, associated with an inefficient depolymerization of nuclear actin, specifically illustrate how endocannabinoids, by regulating circRNA cargo, may contribute to sperm morpho-cellular maturation

About the shallow resistivity structure of Vesuvius volcano

Magnetotelluric (MT) soundings performed in the past in the volcanic area of Mt. Vesuvius by two independent research groups showed in the same places MT apparent resistivity curves with very similar shape, but statical- ly shifted by one order of magnitude, at least. To try to resolve this ambiguity new controlled source audio-mag- netotelluric (CSAMT) measurements have been carried out in the same MT sites. The interpretation of the CSAMT dataset, combined with that of two shallow dipole-dipole geoelectrical resistivity tomographies previ- ously carried out in the area have allowed a reliable electrical structure to be recovered down to a few km of depth, which will next be used for a best constrained re-interpretation of the deep MT soundings