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We consider the problem of partitioning a spectrum band into $M$ channels of equal bandwidth, and then further assigning these $M$ channels into $P$ licensed channels and $M-P$ unlicensed channels. Licensed channels can be accessed both for licensed and opportunistic use following a tiered structure that has a higher priority for licensed use. Unlicensed channels can be accessed only for opportunistic use. We address the following question in this paper. Given a market setup, what values of $M$ and $P$ maximize the net spectrum utilization of the spectrum band? While this problem is fundamental, it is highly relevant practically, e.g., in the context of partitioning the recently proposed Citizens Broadband Radio Service band. If $M$ is too high or too low, it may decrease spectrum utilization due to limited channel capacity or due to wastage of channel capacity, respectively. If $P$ is too high (low), it will not incentivize the wireless operators who are primarily interested in unlicensed channels (licensed channels) to join the market. These tradeoffs are captured in our optimization problem which manifests itself as a two-stage Stackelberg game. We design an algorithm to solve the Stackelberg game and hence find the optimal $M$ and $P$ . The algorithm design also involves an efficient Monte Carlo integrator to evaluate the expected value of the involved random variables like spectrum utilization and operators’ revenue. We also benchmark our algorithms using numerical simulations.

Coronavirus disease 19 (COVID19) is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Currently, several countries are at risk of the pandemic caused by this virus. In the absence of any vaccine or virus-specific antiviral treatments, the need is to fast track search for potential drug candidates to combat the virus. Though there are known drugs that are being repurposed to fight against the SARS-CoV-2, there is a requirement for the virus-specific drugs at the earliest. One of the main drug targets of SARS-CoV-2 is an essential non-structural protein, 3CL protease, critical for the life cycle of the virus. We have used molecular docking studies to screen a chemically diverse set of small molecules to identify potential drug candidates to target this protein. Of the 22,630 molecules from varied small molecule libraries, based on the binding affinities and physicochemical properties, we finalized 30 molecules to be potential drug candidates. Eight of these molecules bind in a manner allowing for the scope of a nearly orthogonal backside nucleophilic attack on their suitably placed electrophilic carbonyl groups by the thiol group of cysteine residue 145, while remaining inside a 4 Ǻ distance range. It is interesting since carbonyl groups are known to be attacked in a similar fashion by external nucleophiles and can be relevant when considering these molecules as potential mechanism-based irreversible inhibitors of the 3CL

Caries is a multifactorial infection that can be caused by Streptococcus mutans. This bacteria is responsible for the formation of oral biofilms and incorporates properties that is conducive for its survival in hostile oral environments. Long-term adverse effects like hypersensitivity reactions, supra-infections and teeth staining coupled with the risk of resistance-development limit use of chemical preparations and antibiotics for caries prevention. Hence plant-based formulations with substantial antimicrobial and anti-cariogenic properties, could serve as alternatives for caries prevention. In this study, a Cymbopogon citratus (lemongrass) oil-in-water emulsion with Tween80/Span80 was formulated and favorably characterized using particle size (252.3±1.15nm with polydispersity index of 0.111± 0.01), FTIR and AFM analyses and stability studies. Its MIC and the MIC of alumina nanoparticles against cultures and isolates of Streptococcus mutans was around 600ppm. However, with the alumina nanoparticle loaded emulsion, the MIC was observed at a much lower concentration of around 400ppm. This nanoparticle incorporated emulsion was also able to inhibit the biofilm formation, with the time kill assay showing a decrease in cell numbers within 60 to 120 minutes post incubation. Alumina incorporated lemon grass oil emulsion may thus to prevent dental caries induced by Streptococcus mutans.

It is widely accepted that the lease duration of spectrum bands sold through auctions plays a crucial role in affecting spectrum utilization. Shorter lease duration increases the frequency of spectrum auctions. Within the scenario studied in this paper, frequent spectrum auctions increases the chances of the spectrum bands being allocated to those operators who can utilize it the best. However, if the lease duration is too short it will not incentivize enough operators to join the market and hence lead to lower competition which in turn deteriorates spectrum utilization. In spite of the importance of lease duration in affecting spectrum utilization, there is no formal study dealing with optimizing the duration of a spectrum lease. This paper presents the first mathematical model to study the effect of lease duration on spectrum utilization under certain market scenario. In such a market scenario, revenue of an operator is the measure of its spectrum utilization. Based on our model, we formulate an optimization problem and develop algorithms to solve the optimization problem for two special cases. Using these algorithms, we numerically study how the optimal characteristics vary with different market parameters.

To meet the ever growing need for wireless spectrum, the Federal Communication Commision (FCC) introduced a spectrum sharing model called the 3-Tier Sharing Framework. In this model, under-utilized federal spectrum will be released for shared use where the highest preference will be given to Tier-1 followed by Tier-2 and then Tier-3. In this paper, we present a model where a wireless operator, who is interested in maximizing its profit, can operate as a Tier-2 and/or a Tier-3 user. Tier-2 is characterized by paid but “almost” guaranteed and interference free channel access while Tier-3 access is free but has lesser guarantee and also faces channel interference. So the operator has to optimally decide between paid but better channel quality and free but degraded channel quality. Also, the operator has to make these decisions without knowing future market parameters like customer demands or channel availability. We use tools from ski-rental literature to design a deterministic online algorithm for leasing channels which does not rely on the knowledge of market statistics. The efficiency of the online algorithm is analyzed by deriving its competitive ratio (CR) and by conducting simulations. The mathematical model for leasing channels is a novel generalization of the classical ski-rental problem. We therefore make fundamental contribution to ski-rental literature which may have diverse applications beyond the problem considered in this paper.

In cloud computing, users scale their resources (computational) based on their need. There is massive literature dealing with such resource scaling algorithms. These works ignore a fundamental constrain imposed by all Cloud Service Providers (CSP), i.e. one has to pay for a fixed minimum duration irrespective of their usage. Such quantization in billing cycles poses problem for users with sporadic workload. In recent literature, Cloud Broker (CB) has been introduced for the benefit of such users. A CB rents resources from CSP and in turn provides service to users to generate profit. Contract between CB and user is that of pay-what-you-use/pay-per-use. However CB faces the challenge of Quantized Billing Cycles as it negotiates with CSP. We design two algorithms, one fully online and the other partially online, which maximizes the profit of the CB. The key idea is to regulate users demand using dynamic pricing. Our algorithm is inspired by the Ski-Rental problem. We derive competitive ratio of these algorithms and also conduct simulations using real world traces to prove the efficiency of our algorithm., Comment: 11 pages, 9 figures

Background Ageing involves oxidative stress mediated by Reactive Oxygen Species (ROS) and mitochondrial dysfunction. The present work demonstrates the protective effect of PQQ producing EcN against rotenone induced mitochondrial oxidative stress and consequence of mitochondrial and cellular dysfunction in naturally ageing rat model. PQQ is a potent antioxidant molecule also known to stimulate mitochondrial biogenesis and function in mammals. Methods Firstly, adult rats (16–18 weeks old) were treated with rotenone (2.5 mg/kg body weight; i.p.) daily for 28 days along with PQQ (10 mg/kg diet, daily) and modified probiotic EcN strains (10 8 CFU twice weekly). Secondly, ageing rats (48–50 weeks old) were gavaged with probiotic EcN strains (10 8 CFU twice weekly) and PQQ (10 mg/kg diet, daily) for 8 months. Results PQQ producing EcN-5 treatment prevented rotenone induced hepatic oxidative stress and mitochondrial damage in rats as assessed by reduced lipid peroxidation (29%), elevated glutathione (GSH) content (43%), increased catalase (52%) and superoxide dismutase (52%) activities when compared to only rotenone treatment. Moreover, increased hepatic mitochondrial content (41%), peroxisome proliferator-activated receptor-gamma coactivator 1-alpha (PGC-1α) mRNA (25%) and mitochondrial Superoxide Dismutase (Mit-SOD) activity (94%) were also observed in EcN-5 treated rats. Rotenone treated rats did not exhibit gain in body weight, whereas rats co-treated with EcN-5 showed significant restoration in body weight gain. Furthermore, weekly administration of EcN-5 to naturally ageing rats for eight months resulted in significant reduction of oxidative stress in hepatic and colonic tissues (assessed by lipid peroxidation, GSH content and catalase and SOD enzyme activities) along with increase in hepatic mitochondrial enzyme activities (Mit-SOD and succinate dehydrogenase) and biogenesis, when compared to untreated rats. Additionally, these rats also exhibited reduced expression of fatty acid synthase (50%) and increased expression of acyl coenzyme oxidase (225%) genes in liver in contrast to untreated rats resulting in lowered triglyceride (13% & 13.5%) and cholesterol (21% & 27%) levels in plasma and liver, respectively. Increased levels of butyrate (93%), propionate (45%) and acetate (18%) were also found in colonic content of these rats. PQQ administered daily (supplemented in diet) exhibited more or less similar effect as weekly gavaged EcN-5 in both the experiments, which substantiate that these effects are mediated by PQQ. Conclusion These results suggest that genetically modified EcN-5 can be used as a nutritional supplement which can reduce age related oxidative stress and hyperlipidemia. Furthermore, it also rejuvenates healthy mitochondria by stimulating mitochondrial biogenesis and metabolism.

Memristors, initially introduced in the 1970s, have received increased attention upon successful synthesis in 2008. Considerable work has been done on modeling and applications in specific areas, however, very little is known on the potential of memristors for control applications. Being nanoscopic variable resistors, it is intuitive to think of using them as a variable gain. The main contribution of this paper is the development of a memristive analog gain control framework and theoretic foundation of a control strategy which can be implemented using this framework. Analog memristive controllers may find applications in control of large array of miniaturized devices where robust and adaptive control is needed due to parameter uncertainty and ageing issues., The main inclusion in this version is a brief discussion of "Global solution of BMI Eigenvalue Problem" in Appendix B and the definition of control theoretic ideas in Appendix C

The use of Casimir functions towards control of physical systems is well known, both in the context of Energy shaping as well as Power shaping techniques. In this paper we show that by use of a Memristive element in the controller design enables us to generate additional Casimir functions relating the state of the memristor to the plant state. This additional conserved quantity manifests itself in the control law in form of a state-modulated gain. We present our results with examples in the context of control by Casimir generation in the port-Hamiltonian framework, which essentially deals with shaping the energy of the system. We also present the applicability of the results towards control by power shaping of electrical circuits in the Brayton-Moser framework for modeling of electrical networks.

In India, most of the commercial transport is being carried out by the railway network and therefore, any problems in the same has the capacity to induce major damage to the economy-notwithstanding the societal impact of loss of life or limb. This paper proposes a cost effective yet robust solution to the problem of railway crack detection utilizing a method that is unique in the sense that while it is simple, the idea is completely novel and hitherto untested. The paper discusses the technical and design aspects in detail and also provides the proposed robust crack detection algorithm. The paper also presents the details of the implementation results of the RRCDS utilizing simple components inclusive of a GPS module, GSM Modem and LED-LDR based crack detector assembly. The proposed scheme has been modeled for robust implementation in the Indian scenario.