solc-verify: A Modular Verifier for Solidity Smart Contracts

We present solc-verify, a source-level verification tool for Ethereum smart contracts. Solc-verify takes smart contracts written in Solidity and discharges verification conditions using modular program analysis and SMT solvers. Built on top of the Solidity compiler, solc-verify reasons at the level of the contract source code, as opposed to the more common approaches that operate at the level of Ethereum bytecode. This enables solc-verify to effectively reason about high-level contract properties while modeling low-level language semantics precisely. The contract properties, such as contract invariants, loop invariants, and function pre- and post-conditions, can be provided as annotations in the code by the developer. This enables automated, yet user-friendly formal verification for smart contracts. We demonstrate solc-verify by examining real-world examples where our tool can effectively find bugs and prove correctness of non-trivial properties with minimal user effort.Comment: Authors' manuscript. Published in S. Chakraborty and J. A. Navas (Eds.): VSTTE 2019, LNCS 12031, 2020. The final publication is available at Springer via https://doi.org/10.1007/978-3-030-41600-3_1

A transgenic cell line with inducible transcription for studying (CGG)n repeat expansion mechanisms

There are more than 30 inherited human disorders connected with repeat expansion (myotonic dystrophy type I, Huntington’s disease, Fragile X syndrome). Fragile X syndrome is the most common reason for inherited intellectual disability in the human population. The ways of the expansion development remain unclear. An important feature of expanded repeats is the ability to form stable alternative DNA secondary structures. There are hypotheses about the nature of repeat instability. It is proposed that these DNA secondary structures can block various stages of DNA metabolism processes, such as replication, repair and recombination and it is considered as the source of repeat instability. However, none of the hypotheses is fully conf irmed or is the only valid one. Here, an experimental system for studying (CGG)n repeat expansion associated with transcription and TCR­-NER is proposed. It is noteworthy that the aberrations of transcription are a poorly studied mechanism of (CGG)n instability. However, the proposed systems take into account the contribution of other processes of DNA metabolism and, therefore, the developed systems are universal and applicable for various studies. Transgenic cell lines carrying a repeat of normal or premutant length under the control of an inducible promoter were established and a method for repeat instability quantif ication was developed. One type of the cell lines contains an exogenous repeat integrated into the genome by the Sleeping Beauty transposon; in another cell line, the vector is maintained as an episome due to the SV40 origin of replication. These experimental systems can serve for f inding the causes of instability and the development of therapeutic agents. In addition, a criterion was developed for the quantif ication of exogenous (CGG)n repeat instability in the transgenic cell lines’ genome

Топографо-анатомическое и клиническое обоснование использования доступа Мерзликина-Парамоновой при операциях на печени

The purpose of the study was to assess results of Merzlikin-Paramonova's approach in liver surgeries.Material and Methods. The topographical-anatomical and spatial relationships were studied on 20 corpses, taking into account assessment criteria according to A.Yu. Sozon-Yaroshevich. In clinical settings, Merzlikin-Paramonova's approach was applied in the treatment of 81 patients with hepatic diseases (cancer, hemangioma, alveococcosis), who underwent radical and palliative surgeries. Short-and long-term treatment outcomes during a 5 year follow-up were analyzed. Merzlikin-Paramonova's approach provided a sufficient overview of the liver, easy manipulation in the area of large bile ducts and blood vessels, as well as the ability to perform lymphodissection and combined operations.Results. The Merzlikin-Paramonova's approach to liver surgeries has significant advantages over traditional surgical approaches, providing a good overview for revision of both primary and recurrent liver lesions. This surgical approach allowed the number of postoperative complications to be reduced due to less wound tension, rapid relief of pain and reduction in intra-abdominal hypertension, thus shortening the treatment time for patients. In the long-term postoperative period, the incidence of postoperative hernias decreased due to less damage to the nerve terminals of the anterior abdominal wall.Conclusion. Merzlikin-Paramonova's approach is slightly traumatic due to innervation and muscle structure of the abdominal wall, is more physiological for the patient, and has a low rate of complications. This approach provides a good access to the organ requiring surgery and is able to perform radical cytoreductive surgeries. Merzlikin-Paramonova's approach to liver surgeries can be recommended for active implementation in clinical practice.Целью исследования является изучение результатов внедрения в клиническую практику доступа Мерзликина-Парамоновой.Материал и методы. В эксперименте на 20 трупах проведено изучение топографо-анатомических, пространственных взаимоотношений в ране с учетом критериев оценки по А.Ю. Созон-Ярошевичу. В клинике доступ Мерзликина-Парамоновой применен в лечении 81 пациента с очаговой патологией печени (рак, гемангиома, альвеококкоз), которым выполнены радикальные и паллиативные оперативные вмешательства. Прослежены ближайшие и отдаленные результаты в сроки до 5 лет после лечения. При всех перечисленных вмешательствах предлагаемый доступ обеспечивал достаточный обзор печени, свободу манипуляций в области крупных желчных протоков, сосудов, в том числе и криоинструментами, возможность выполнения лимфодиссекции и комбинированных операций.Результаты. Предложенный доступ для оперативного вмешательства на печени имеет значительные преимущества перед традиционными, обеспечивает хороший обзор для ревизии оперируемого органа как при первичном, так и рецидивном поражении. Использование доступа позволило провести более раннюю активизацию больных, снизить количество послеоперационных осложнений за счет меньшего натяжения раны, скорейшего купирования болевого синдрома и снижения внутриабдоминальной гипертензии, что позволило сократить сроки лечения больных. В отдаленном послеоперационном периоде снижалась частота развития послеоперационных грыж за счет меньшего повреждения нервных окончаний передней брюшной стенки.Заключение. Доступ Мерзликина-Парамоновой малотравматичен за счет того, что учитываются иннервация и мышечное строение стенки брюшной полости, а также более физиологичен, что подтверждается низкими показателями осложнений. Хорошая доступность оперируемого органа, возможность для расширения и выполнения радикальных и циторедуктивных операций показали, что доступ создает достаточный простор для ревизии и оперативного вмешательства как в случае первичного, так и метастатического поражения органа. С учетом этого заявленный способ доступа может быть рекомендован для активного внедрения в клиническую практику

Verifying Liquidity of Bitcoin Contracts

A landmark security property of smart contracts is liquidity: in a non-liquid contract, it may happen that some funds remain frozen. The relevance of this issue is witnessed by a recent liquidity attack to the Ethereum Parity Wallet, which has frozen ~160M USD within the contract, making this sum unredeemable by any user. We address the problem of verifying liquidity of Bitcoin contracts. Focussing on BitML, a contracts DSL with a computationally sound compiler to Bitcoin, we study various notions of liquidity. Our main result is that liquidity of BitML contracts is decidable, in all the proposed variants. To prove this, we first transform the infinite-state semantics of BitML into a finite-state one, which focusses on the behaviour of any given set of contracts, abstracting the context moves. With respect to the chosen contracts, this abstraction is sound and complete. Our decision procedure for liquidity is then based on model-checking the finite space of states of the abstraction

Calcium-regulated interactions of human α-lactalbumin with bee venom melittin

Affinity chromatography, fluorescence and circular dichroism spectroscopy methods have been used to study the interaction of melittin, a 26-residue peptide from bee venom, with Ca2+-binding α-lactalbumin from human milk. It has been revealed that melittin binds to the apo- and acidic states of α-lactalbumin while the presence of Ca2+ makes the interaction essentially weaker. The association constant for the complex of melittin with apo-α-lactalbumin determined from spectropolarimetric melittin-titration data is 2×107 M−1. The complexation of α-lactalbumin with melittin decreases its affinity to Ca2+ by three orders of magnitude. The interaction of apo-α-lactalbumin with melittin causes some changes in the environment of its aromatic amino acid residues and drastically alters the conformation of melittin, increasing its α-helical content but leaving its single tryptophan residue accessible to water. In the case of the acidic state of α-lactalbumin the interaction does not induce an increase in α-helical content of melittin