292 research outputs found
Glycosaminoglycans in the human cornea: age-related changes
Abstract
AIM:
To investigate possible age-related changes in glycosaminoglycans (GAGs) in the human cornea. The substances today called GAGs were previously referred to as mucopolysaccharides.
METHODS:
Samples of human cornea were taken from 12 younger (age 21 ± 1.2) and 12 older (age 72 ± 1.6) male subjects. Samples were weighed, homogenized, and used for biochemical and molecular analyses. All the quantitative results were statistically analyzed.
RESULTS:
The human cornea appears to undergo age-related changes, as evidenced by our biochemical and molecular results. The total GAG and hyaluronic acid counts were significantly higher in the younger subjects than in the older subjects. The sulfated heavy GAGs, such as chondroitin, dermatan, keratan, and heparan sulfate, were lower in the younger subjects than in the older subjects.
DISCUSSION:
GAGs of the human cornea undergo numerous age-related changes. Their quantity is significantly altered in the elderly in comparison with younger subjects. GAGs play an important role in age-related diseases of the human cornea
On a New, Efficient Framework for Falsifiable Non-interactive Zero-Knowledge Arguments
Et kunnskapsløst bevis er en protokoll mellom en bevisfører og en attestant. Bevisføreren har som mål å overbevise attestanten om at visse utsagn er korrekte, som besittelse av kortnummeret til et gyldig kredittkort, uten å avsløre noen private opplysninger, som for eksempel kortnummeret selv. I mange anvendelser er det ønskelig å bruke IIK-bevis (Ikke-interaktive kunnskapsløse bevis), der bevisføreren produserer kun en enkelt melding som kan bekreftes av mange attestanter.
En ulempe er at sikre IIK-bevis for ikke-trivielle språk kun kan eksistere ved tilstedeværelsen av en pålitelig tredjepart som beregner en felles referansestreng som blir gjort tilgjengelig for både bevisføreren og attestanten. Når ingen slik part eksisterer liter man av og til på ikke-interaktiv vitne-uskillbarhet, en svakere form for personvern. Studiet av effektive og sikre IIK-bevis er en kritisk del av kryptografi som har blomstret opp i det siste grunnet anvendelser i blokkjeder.
I den første artikkelen konstruerer vi et nytt IIK-bevis for språkene som består av alle felles nullpunkter for en endelig mengde polynomer over en endelig kropp. Vi demonstrerer nytteverdien av beviset ved flerfoldige eksempler på anvendelser. Særlig verdt å merke seg er at det er mulig å gå nesten automatisk fra en beskrivelse av et språk på et høyt nivå til definisjonen av IIK-beviset, som minsker behovet for dedikert kryptografisk ekspertise. I den andre artikkelen konstruerer vi et IIV-bevis ved å bruke en ny kompilator. Vi utforsker begrepet Kunnskapslydighet (et sterkere sikkerhetsbegrep enn lydighet) for noen konstruksjoner av IIK-bevis. I den tredje artikkelen utvider vi arbeidet fra den første artikkelen ved å konstruere et nytt IIK-bevis for mengde-medlemskap som lar oss bevise at et element ligger, eller ikke ligger, i den gitte mengden.
Flere nye konstruksjoner har bedre effektivitet sammenlignet med allerede kjente konstruksjoner.A zero-knowledge proof is a protocol between a prover, and a verifier. The prover aims to convince the verifier of the truth of some statement, such as possessing credentials for a valid credit card, without revealing any private information, such as the credentials themselves. In many applications, it is desirable to use NIZKs (Non-Interactive Zero Knowledge) proofs, where the prover sends outputs only a single message that can be verified by many verifiers.
As a drawback, secure NIZKs for non-trivial languages can only exist in the presence of a trusted third party that computes a common reference string and makes it available to both the prover and verifier. When no such party exists, one sometimes relies on non interactive witness indistinguishability (NIWI), a weaker notion of privacy. The study of efficient and secure NIZKs is a crucial part of cryptography that has been thriving recently due to blockchain applications.
In the first paper, we construct a new NIZK for the language of common zeros of a finite set of polynomials over a finite field. We demonstrate its usefulness by giving a large number of example applications. Notably, it is possible to go from a high-level language description to the definition of the NIZK almost automatically, lessening the need for dedicated cryptographic expertise. In the second paper, we construct a NIWI using a new compiler. We explore the notion of Knowledge Soundness (a security notion stronger than soundness) of some NIZK constructions. In the third paper, we extended the first paper’s work by constructing a new set (non-)membership NIZK that allows us to prove that an element belongs or does not belong to the given set.
Many new constructions have better efficiency compared to already-known constructions.Doktorgradsavhandlin
Insolita causa di addome acuto in paziente adulto: l’ileo biliare
L’ileo biliare è una condizione morbosa rara descritta tra le complicanze della litiasi della colecisti. È causa dell’1-3% delle ostruzioni meccaniche del piccolo intestino. Interessa più frequentemente pazienti di età compresa tra 63 e 85 anni. La diagnosi pre-operatoria
è generalmente posta con ritardo variabile da 1 a 10 giorni per l’assenza di una sintomatologia specifica.
Caso clinico. Gli Autori riportano il caso di un uomo di 50 anni in cui è stata posta diagnosi di occlusione meccanica del piccolo intestino da voluminosa concrezione litiasica. L’occlusione ileale è stata dimostrata con la TC. Il paziente è stato sottoposto in urgenza ad intervento
chirurgico, in un unico tempo, di enterolitotomia, colecistectomia e riparazione della fistola duodenale. Il decorso clinico è stato regolare e il paziente è stato dimesso in XIV giornata.
Discussione. Nel nostro caso la diagnosi di ileo biliare è stata posta con un ritardo di 5 giorni. L’ecotomografia del fegato e delle vie biliari non è stata in grado di visualizzare la colecisti. La diagnosi è stata
posta con la TC che si conferma gold standard diagnostico.
Conclusioni. Lo stato clinico del paziente influenza la strategia chirurgica. Nel nostro paziente, considerato a basso rischio, è stato possibile l’intervento chirurgico in un unico tempo. La procedura in due tempi, enterolitotomia e successiva colecistectomia con riparazione della fistola,
va riservata ai pazienti ad alto rischio
Set (Non-)Membership NIZKs from Determinantal Accumulators
We construct a falsifiable set (non-)membership NIZK that is considerably more efficient than known falsifiable set (non-)membership NIZKs. It also has a universal CRS. is based on the novel concept of determinantal accumulators. Determinantal primitives have a similar relation to recent pairing-based (non-succinct) NIZKs of Couteau and Hartmann (Crypto 2020) and Couteau et al. (CLPØ, Asiacrypt 2021) that structure-preserving primitives have to the Groth-Sahai NIZK. We also extend CLPØ by proposing efficient (non-succinct) set non-membership arguments for a large class of languages
Constant-Size zk-SNARKs in ROM from Falsifiable Assumptions
We prove that the seminal KZG polynomial commitment scheme (PCS) is black-box extractable under a simple falsifiable assumption ARSDH. To create an interactive argument, we construct a compiler that combines a black-box extractable non-interactive PCS and a polynomial IOP (PIOP). The compiler incurs a minor cost per every committed polynomial. Applying the Fiat-Shamir transformation, we obtain slightly less efficient variants of well-known PIOP-based zk-SNARKs, such as Plonk, that are knowledge-sound in the ROM under the ARSDH assumption. Importantly, there is no need for idealized group models or knowledge assumptions. This results in the first known zk-SNARKs in the ROM from falsifiable assumptions with both an efficient prover and constant-size argument
On Knowledge-Soundness of Plonk in ROM from Falsifiable Assumptions
Lipmaa, Parisella, and Siim [Eurocrypt, 2024] proved the extractability of the KZG polynomial commitment scheme under the falsifiable assumption ARSDH. They also showed that variants of real-world zk-SNARKs like Plonk can be made knowledge-sound in the random oracle model (ROM) under the ARSDH assumption. However, their approach did not consider various batching optimizations, resulting in their variant of Plonk having approximately 3.5 times longer argument. Our contributions are: (1) We prove that several batch-opening protocols for KZG, used in modern zk-SNARKs, have computational special-soundness under the ARSDH assumption. (2) We prove that interactive Plonk has computational special-soundness under the ARSDH assumption and a new falsifiable assumption TriRSDH. We also prove that a minor modification of the interactive Plonk has computational special-soundness under only the ARSDH assumption. The Fiat-Shamir transform can be applied to obtain non-interactive versions, which are secure in the ROM under the same assumptions
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