An Automata-Theoretic Approach to the Verification of Distributed Algorithms

We introduce an automata-theoretic method for the verification of distributed algorithms running on ring networks. In a distributed algorithm, an arbitrary number of processes cooperate to achieve a common goal (e.g., elect a leader). Processes have unique identifiers (pids) from an infinite, totally ordered domain. An algorithm proceeds in synchronous rounds, each round allowing a process to perform a bounded sequence of actions such as send or receive a pid, store it in some register, and compare register contents wrt. the associated total order. An algorithm is supposed to be correct independently of the number of processes. To specify correctness properties, we introduce a logic that can reason about processes and pids. Referring to leader election, it may say that, at the end of an execution, each process stores the maximum pid in some dedicated register. Since the verification of distributed algorithms is undecidable, we propose an underapproximation technique, which bounds the number of rounds. This is an appealing approach, as the number of rounds needed by a distributed algorithm to conclude is often exponentially smaller than the number of processes. We provide an automata-theoretic solution, reducing model checking to emptiness for alternating two-way automata on words. Overall, we show that round-bounded verification of distributed algorithms over rings is PSPACE-complete.Comment: 26 pages, 6 figure

Weighted Tiling Systems for Graphs: Evaluation Complexity

We consider weighted tiling systems to represent functions from graphs to a commutative semiring such as the Natural semiring or the Tropical semiring. The system labels the nodes of a graph by its states, and checks if the neighbourhood of every node belongs to a set of permissible tiles, and assigns a weight accordingly. The weight of a labeling is the semiring-product of the weights assigned to the nodes, and the weight of the graph is the semiring-sum of the weights of labelings. We show that we can model interesting algorithmic questions using this formalism - like computing the clique number of a graph or computing the permanent of a matrix. The evaluation problem is, given a weighted tiling system and a graph, to compute the weight of the graph. We study the complexity of the evaluation problem and give tight upper and lower bounds for several commutative semirings. Further we provide an efficient evaluation algorithm if the input graph is of bounded tree-width

Deciding Conjugacy of a Rational Relation

A rational relation is conjugate if every pair of related words are conjugates. It is shown that checking whether a rational relation is conjugate is decidable. For this, we generalise the Lyndon-Sch\"utzenberger's theorem from word combinatorics. A consequence of the generalisation is that a set of pairs generated by a sumfree rational expression is conjugate if and only if there is a word witnessing the conjugacy of all the pairs

Prevalence of Oligohydramnios among the Third Trimester Pregnant Women and Its Perinatal Outcome

Oligohydramnios means reduced liquor. There is an association among oligohydramnios and both intrauterine growth restriction and increased perinatal mortality. There is a change in normal amniotic fluid volume with gestational age and estimating the changes accurately have changed over the years. Oligohydramnios presents a threat to the fetus and has been associated with increased risk of intrauterine growth retardation, meconium aspiration syndrome, severe birth asphyxia, low APGAR scores and congenital anamolies. It is associated with perinatal morbidity and mortality. Therefore early detection of oligohydramnios and its management is very important. Aim of this study is to know the perinatal outcome in the third trimester diagnosed case of oligohydramnios

Data Multi-Pushdown Automata

We extend the classical model of multi-pushdown systems by considering systems that operate on a finite set of variables ranging over natural numbers. The conditions on variables are defined via gap-order constraints that allow to compare variables for equality, or to check that the gap between the values of two variables exceeds a given natural number. Furthermore, each message inside a stack is equipped with a data item representing its value. When a message is pushed to the stack, its value may be defined by a variable. When a message is popped, its value may be copied to a variable. Thus, we obtain a system that is infinite in multiple dimensions, namely we have a number of stacks that may contain an unbounded number of messages each of which is equipped with a natural number. It is well-known that the verification of any non-trivial property of multi-pushdown systems is undecidable, even for two stacks and for a finite data-domain. In this paper, we show the decidability of the reachability problem for the classes of data multi-pushdown system that admit a bounded split-width (or equivalently a bounded tree-width). As an immediate consequence, we obtain decidability for several subclasses of data multi-pushdown systems. These include systems with single stacks, restricted ordering policies on stack operations, bounded scope, bounded phase, and bounded context switches

CRYPTOSOMES: A REVOLUTIONARY BREAKTHROUGH IN NOVEL DRUG DELIVERY

The vesicular drug delivery systems are promising approaches to overthrown the problems of drugs having lesser bioavailability and rapid elimination from the body. The four type of lipid based drug delivery systems are: solid-lipid particulate system, emulsion based system, solid lipid tablet and vesicular system. Cryptosomes, a novel emerging vesicular drug delivery system which can overcome the disadvantages associated with conventional drug delivery systems like high stability, increased bioavailability, sustained release, decreased elimination of rapidly metabolizable drugs etc. The word Cryptosome was orginated from Greek word ‘’Crypto’’ means hidden and ‘’Soma’’ means body. It is formed from the mixture of phospholipids like distearoyl phosphatidyl ethanolamine-polyethylene glycol (DSPE-PEG) with distearoylphosphatidylcholine. These entire information regarding its origin and formation is explained in Dinesh Kumar et al. Vesicular systems symbolizes the use of vesicles in the different fields as carrier system or additives. This review disclose various vesicular drug delivery system and point out the advancement of cryptosome in the world of drug delivery. This review would help researchers involved in the field of vesicular drug delivery

STRUCTURE-BASED MULTITARGETED MOLECULAR DOCKING ANALYSIS OF PYRAZOLE-CONDENSED HETEROCYCLICS AGAINST LUNG CANCER

Objective: The significant drawbacks of chemotherapy are that it destroys healthy cells, resulting in adverse effects. Hence, there is a need to adopt new techniques to develop cancer-specific chemicals that target the molecular pathways in a non-toxic fashion. This study aims to screen pyrazole-condensed heterocyclics for their anticancer activities and analyse their enzyme inhibitory potentials EGFR, ALK, VEGFR and TNKS receptors. Methods: The structures of the compounds were confirmed by IR, NMR and Mass spectral studies. The in silico techniques applied in this study were molecular docking and pharmacophore modeling to analyse the protein-ligand interactions, as they have a significant role in drug discovery. Drug-likeness properties were assessed by the Lipinski rule of five and ADMET properties. Anticancer activity was performed by in vitro MTT assay on lung cancer cell lines. Results: The results confirm that all the synthesised pyrazole derivatives interacted well with the selected targets showing docking scores above-5 kcal/mol. Pyrazole 2e interacted well with all the four lung cancer targets with its stable binding mode and was found to be potent as per the in vitro reports, followed by compounds 3d and 2d. Pharmacophore modeling exposed the responsible features responsible for the anticancer action. ADMET properties reported that all the compounds were found to have properties within the standard limit. The activity spectra of the pyrazoles predicted that pyrazolopyridines (2a-2e) are more effective against specific receptors such as EGFR, ALK and Tankyrase. Conclusion: Thus, this study suggests that the synthesised pyrazole derivatives can be further investigated to validate their enzyme inhibitory potentials by in vivo studies

FORMULATION AND EVALUATION OF LORAZEPAM ENCAPSULATED COLLAGEN/PECTIN BUCCAL PATCH

Objective: To formulate and characterize Lorazepam loaded buccal patches using mucoadhesive, biodegradable, natural polymers-pectin (hydrophilic) and collagen (lipophilic) for treating epileptic seizures. Methods: Lorazepam loaded buccal patches were prepared by solvent casting method and were subjected to various Physico-chemical evaluation parameters to find the optimized buccal patch. The in vitro drug release study and ex vivo permeation study was carried out. The stability study and histopathological study of optimized Lorazepam loaded buccal patch was also carried out. Results: From in vitro drug release study, it was found that Lorazepam loaded buccal patch (B4) exhibited maximum drug release of 96.16 %±0.07 than other formulations at the end of 4 h, indicating an initial burst release followed by sustained release with release kinetics as Higuchi diffusion model. Based on the in vitro drug release, % drug content, % swelling index, folding endurance, B4 formulation was considered as optimised formulation and was further characterized. Ex vivo permeation study revealed that the cumulative amount of drug permeated from optimised Lorazepam loaded buccal patch (B4) was higher (3831.4±0.21µg/cm2) than marketed Midazolam buccal solution (1724±0.12 µg/cm2) and control drug solution (895.42±0.07 µg/cm2) with an enhancement ratio of 4.8. B4 formulation also showed a higher flux value (12.52±0.02µg/cm2/hr) compared to marketed formulation (5.732±0.01 µg/cm2) and control drug solution (2.563±0.03 µg/cm2) of P<0.05. The histopathological study using bovine buccal mucosa revealed that the B4 formulation is safe for buccal application. The stability study confirmed that B4 formulation is stable in both room and refrigeration conditions. Hence the formulated Lorazepam loaded buccal patch seems to be a promising carrier for the enhanced buccal delivery of Lorazepam in treating epileptic seizures. Conclusion: The formulated Lorazepam loaded collagen/pectin buccal patch was found to be an efficient and stable route for the buccal delivery of Lorazepam in treating acute epileptic seizures which could be further explored scientifically

UFASOMES: UNSATURATED FATTY ACID BASED VESICULAR DRUG DELIVERY SYSTEM

Various novel drug delivery systems have been developed encompassing several administration routes to deliver drugs at a rate decided as per the need of the body during the course of treatment and to achieve targeted therapy, also decreases undesirable side effects. Different types of vesicular drug delivery systems were developed, such as liposomes, niosomes, ufasomes etc. Ufasomes are unsaturated fatty acid vesicles which is a suspension of closed lipid bilayer formed from fatty acid and their ionized species having limited, narrow pH ranging from 7-9. Composition of fatty acid molecules is such that the hydrocarbon tails are pointed towards the inner core of the membrane and the carboxyl group are in touch with water. Stable ufasomes preparation mainly relies on appropriate choice of fatty acid, cholesterol quantity, range of the pH, buffer and lipoxygenase amount. Recent innovation provides very efficient features such as stability considerations, dynamic features and microscopic features of ufasomes. The article furthermore provides the difference between ufasomes with liposomes. For this review, the complete databases have been collected from various search engines such as researchgate, elsevier, pubmed, sciencedirect, google scholar, scopus etc., from the year 1965-2020 using the following keywords