759 research outputs found

    Model checking time-constrained scenario-based specifications

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    We consider the problem of model checking message-passing systems with real-time requirements. As behavioural specifications, we use message sequence charts (MSCs) annotated with timing constraints. Our system model is a network of communicating finite state machines with local clocks, whose global behaviour can be regarded as a timed automaton. Our goal is to verify that all timed behaviours exhibited by the system conform to the timing constraints imposed by the specification. In general, this corresponds to checking inclusion for timed languages, which is an undecidable problem even for timed regular languages. However, we show that we can translate regular collections of time-constrained MSCs into a special class of event-clock automata that can be determinized and complemented, thus permitting an algorithmic solution to the model checking problem

    Implementation of Peltier Cooling in Hermetically Sealed Electronic Packaging Unit for Sub-sea Vessel

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    This paper presents the methodology adopted for implementation of Peltier cooling in hermetically sealed electronic packaging units used in sub-sea vessels. In sub-sea vessels, sonar front-end electronics is packaged in hermetically sealed electronic packaging units. The thermal design of the unit is a highly challenging task considering the heat dissipation of 300W from the electronics, non-availability of chilled air for cooling and IP68 sealing requirements. Cooling fans cannot be integrated, since these units are to be placed in acoustically sensitive pressure capsule area of the subsea vessel. The electronic cooling in this unit is achieved using conduction cooling with external fins. To enhance the cooling, suitable Peltier cooling (Thermo-electric cooling or TEC) module is selected and implemented with the system. Computational fluid dynamic analysis of the unit is carried-out to study the air-flow and thermal performances with Peltier cooler. The unit is realised and the estimated temperatures validated by experimental temperature measurements on the realised unit. The measured temperatures are within the safe operating limits of the electronic components and hence the cooling design of the unit is satisfactory. It is also observed that maximum temperature reduction has occurred at 1.5A current and card edge temperature of Printed circuit board lowered by 9.28 °C by implementing Peltier cooling

    Nanostructured Gas Sensors for Health Care: An Overview

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    Nanostructured platforms have been utilized for fabrication of small, sensitive and reliable gas sensing devices owing to high functionality, enhanced charge transport and electro-catalytic property. As a result of globalization, rapid, sensitive and selective detection of gases in environment is essential for health care and security. Nonmaterial such as metal, metal oxides, organic polymers, and organic-inorganic hybrid nanocomposites exhibit interesting optical, electrical, magnetic and molecular properties, and hence are found potential gas sensing materials. Morphological, electrical, and optical properties of such nanostructures can be tailored via controlling the precursor concentration and synthesis conditions resulting to achieve desired sensing. This review presents applications of nano-enabling gas sensors to detect gases for environment monitoring. The recent update, challenges, and future vision for commercial applications of such sensor are also described here

    Comparison of outcomes after open versus robotic kidney transplantation: A systematic review and meta-analysis

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    INTRODUCTION: This meta-analysis compares the clinical outcomes of robot-assisted kidney transplant (RAKT) to open kidney transplant (OKT). METHODS: A systematic search of Scopus and MEDLINE databases was carried out using a combination of keywords to identify studies comparing RAKT to OKT. Baseline characteristics and preoperative and postoperative data were collected along with data on the short- and long-term outcomes. The study was registered in PROSPERO and Assessing the Methodological Quality of Systematic Reviews and Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) guidelines were followed. RESULTS: A total of 16 studies were included with a total of 2555 patients, of which 677 underwent RAKT and 1878 underwent OKT. This meta-analysis shows a significant benefit of RAKT over OKT in terms of less intra-operative blood loss, smaller incision length, less postoperative pain scores at 24 and 48 hours, and a lower incidence of surgical site infections (SSIs), especially in obese patients. In addition, the incidence of postoperative lymphoceles was lower in the RAKT group compared to the OKT group, although not statistically significant. There was no difference between the two groups in terms of short-term graft functional outcomes and overall survival. The number of deceased donor recipients undergoing RAKT was very small. At the time of reporting this meta-analysis, no randomized controlled trials (RCTs) had been published. CONCLUSION: This meta-analysis showed that RAKT is a safe and feasible alternative to OKT, especially in obese individuals. Further trials are needed to confirm the safety, efficacy, and cost-effectiveness of RAKT

    Towards a Theory of Regular MSC Languages

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    Message Sequence Charts (MSCs) are an attractive visual formalism widely used to capture system requirements during the earlydesign stages in domains such as telecommunication software. It isfruitful to have mechanisms for specifying and reasoning about collections of MSCs so that errors can be detected even at the requirements level. We propose, accordingly, a notion of regularity for collections of MSCs and explore its basic properties. In particular, weprovide an automata-theoretic characterization of regular MSC languages in terms of finite-state distributed automata called boundedmessage-passing automata. These automata consist of a set of sequential processes that communicate with each other by sending andreceiving messages over bounded FIFO channels. We also provide alogical characterization in terms of a natural monadic second-orderlogic interpreted over MSCs.A commonly used technique to generate a collection of MSCs isto use a Message Sequence Graph (MSG). We show that the class oflanguages arising from the so-called locally synchronized MSGs constitute a proper subclass of the languages which are regular in our sense.In fact, we characterize the locally synchronized MSG languages asthe subclass of regular MSC languages that are finitely generated

    Polydopamine mediated self-cleaning of high-flux pH-responsive isoporous membranes for filtration applications

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    A major challenge in membrane filtration is fouling which reduces the membrane performance. The fouling is mainly due to the adhesion of foulants on the membrane surfaces. In this work, we studied the fouling behavior of polystyrene-b-poly(4-vinylpyridine) (PS-b-P4VP) isoporous membrane and the mussel inspired polydopamine/L-Cysteine isoporous zwitterionic membrane. The polystyrene-b-poly(4-vinylpyridine) (PS-b-P4VP) isoporous membrane was fabricated via self-assembly and non-solvent induced phase separation.1 Subsequently, the isoporous membrane was modified through a mild mussel-inspired polydopamine (PDA) coating by retaining the isoporous morphology and water flux.2 Furthermore, zwitterionic L-Cysteine was anchored on the PDA layer coated membranes via Michael addition reaction at neutral pH and 50oC. The membranes were thoroughly characterized using X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), atomic force microscopy (AFM) and zeta potential measurements. The contact angle and dynamic scanning calorimetry (DSC) measurements were carried out to examine their hydrophilicity. The pH-responsive behaviour of the modified membrane remains unchanged and the antifouling ability after PDA/L-Cysteine functionalization was improved. The modified and unmodified isoporous membranes were tested using humic acid and natural organic matter contaminated solutions at 0.5 bar feed pressure. References Peinemann, K.-V.; Abetz, V.; Simon, P. F. W. Asymmetric Superstructure Formed in a Block Copolymer via Phase Separation. Nat. Mater. 2007, 6, 992–996. Lee, H.; Dellatore, S. M.; Miller, W. M.; Messersmith, P. B. Mussel-Inspired Surface Chemistry for Multifunctional Coatings. Science. 2007, 318, 426–430

    Distinct lymphocyte antigens 6 (Ly6) family members Ly6D, Ly6E, Ly6K and Ly6H drive tumorigenesis and clinical outcome.

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    Stem cell antigen-1 (Sca-1) is used to isolate and characterize tumor initiating cell populations from tumors of various murine models [1]. Sca-1 induced disruption of TGF-β signaling is required in vivo tumorigenesis in breast cancer models [2, 3-5]. The role of human Ly6 gene family is only beginning to be appreciated in recent literature [6-9]. To study the significance of Ly6 gene family members, we have visualized one hundred thirty gene expression omnibus (GEO) dataset using Oncomine (Invitrogen) and Georgetown Database of Cancer (G-DOC). This analysis showed that four different members Ly6D, Ly6E, Ly6H or Ly6K have increased gene expressed in bladder, brain and CNS, breast, colorectal, cervical, ovarian, lung, head and neck, pancreatic and prostate cancer than their normal counter part tissues. Increased expression of Ly6D, Ly6E, Ly6H or Ly6K was observed in sub-set of cancer type. The increased expression of Ly6D, Ly6E, Ly6H and Ly6K was found to be associated with poor outcome in ovarian, colorectal, gastric, breast, lung, bladder or brain and CNS as observed by KM plotter and PROGgeneV2 platform. The remarkable findings of increased expression of Ly6 family members and its positive correlation with poor outcome on patient survival in multiple cancer type indicate that Ly6 family members Ly6D, Ly6E, Ly6K and Ly6H will be an important targets in clinical practice as marker of poor prognosis and for developing novel therapeutics in multiple cancer type
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