8,076 research outputs found
An evolutionary game theoretic approach for stable clustering in vehicular ad hoc networks (VANETs)
University of Technology Sydney. Faculty of Engineering and Information Technology.Finding and maintaining efficient routes for data dissemination in VANETs is a very challenging problem due to the highly dynamic characteristics of VANETs. Clustering in Vehicular Ad hoc Networks (VANETs) is one of the control schemes used to provide efficient and stable routes for data dissemination in VANETs. The rapid changes in the topology of VANETs have instigated frequent cluster formation and reorganization which has seriously affected route stability in Vehicular Ad hoc Networks. Considerable work has been reported into the development of clustering protocols while keeping in view the highly dynamic topology of VANETs, but the objective of imbuing the system with a stable underlay is still in the infant stage. The analytical models used for studying the behaviour of Vehicular Ad hoc Networks have been scarced due to distributed, highly dynamic and self-organizing characteristics of VANETs. In contrast, game theory is emerging as a novel analytical tool that can be used to tackle the technical challenges concerning the current and future problems in wireless and communication networks. A two-layer novel Evolutionary Game Theoretic (EGT) framework is presented to solve the problem of in-stable clustering in VANETs. The aim of this research is to model the interactions of vehicular nodes in VANETs, to retain a stable clustering state of the network with evolutionary equilibrium as the solution of this game. A stable clustering scenario in VANETs is modelled with a reinforcement learning approach to reach the solution of an evolutionary equilibrium. Performance of the proposed “evolutionary game based clustering algorithm” is empirically investigated in different cases and the simulation results show that the system retains cluster stability
Association between pretreatment haemoglobin levels and morphometric characteristics of the tumour, response to neoadjuvant treatment and long-term outcomes in patients with locally advanced rectal cancers
Aim
The study was carried out to investigate whether
pretreatment haemoglobin (Hb) levels act as a biomar-
ker in the management of patients with locally advanced
rectal cancer.
Method\ud
We prospectively collected data on all patients
within our cancer network with localized low rectal
cancer treated with preoperative radiotherapy/chemora-
diotherapy at Mount Vernon Centre for Cancer Treat-
ment between March 1994 and July 2008. Pretreatment
Hb level was assessed as an independent variable for the
whole study sample and dichotomised at a value of 12 g/dl.
A multivariate analysis of covariance (MANCOVA) was
conducted on parameters that had significant association
on univariate analysis of covariance (ANCOVA) and cor-
relational (Kendall tau/Pearson) analyses. Kaplan
–
Meier
survival analysis and Cox proportional hazard models
were used to determine significant prognostic markers.
Statistical significance was set at 0.05.
Results
463 patients (male/female 2:1; median age
=
66 years, interquartile range
=
56.5
–
73.0) were included
in the analysis. There was significant tumour response of
T stage (
P
<
0.001) and N stage (
P
<
0.001), with
17.6% of patients achieving a pathological complete
response. Pretreatment Hb value was inversely related to
the craniocaudal vertical tumour length (
P
=
0.02) and
pretreatment T stage of the tumour (
P
=
0.01). Patients
with Hb levels of
<
12 g/dl and moderately differenti-
ated adenocarcinoma were less responsive. Local recur-
rence was more common in patients with a pretreatment
Hb of
<
12 g/dl (hazard ratio
=
1.78) over a median
follow up of 24 months, but this was not statistically
significant (
P
=
0.08).
Conclusion
The pretreatment Hb level might be used
as a biomarker of rectal tumour morphology, response
to neoadjuvant chemoradiation and risk of local recur-
renc
Non-coding RNAs in endodontic disease
The immunocompetence and regeneration potential of the dental pulp and its surrounding apical tissues have been investigated extensively in the field of endodontics. While research on the role of non-coding RNAs in these tissues is still in its infancy, it is envisioned that improved understanding of the regulatory function of ncRNAs in pulpal and periapical immune response will help prevent or treat endodontic disease. Of particular importance is the role of these RNAs in regenerating the dentin-pulp complex. In this review, we highlight recent progress on the role of non-coding RNAs in the immune response to endodontic infection as well as the repair and regenerative response to injury
Investigation of electrical properties for cantilever-based piezoelectric energy harvester
In the present era, the renewable sources of energy, e.g., piezoelectric materials are in great demand. They play a vital role in the field of micro-electromechanical systems, e.g., sensors and actuators. The cantilever-based piezoelectric energy harvesters are very popular because of their high performance and utilization. In this research-work, an energy harvester model based on a cantilever beam with bimorph PZT-5A, having a substrate layer of structural steel, was presented. The proposed energy scavenging system, designed in COMSOL Multiphysics, was applied to analyze the electrical output as a function of excitation frequencies, load resistances and accelerations. Analytical modeling was employed to measure the output voltage and power under pre-defined conditions of acceleration and load resistance. Experimentation was also performed to determine the relationship between independent and output parameters. Energy harvester is capable of producing the maximum power of 1.16 mW at a resonant frequency of 71 Hz under 1g acceleration, having load resistance of 12 k Omega. It was observed that acceleration and output power are directly proportional to each other. Moreover, the investigation conveys that the experimental results are in good agreement with the numerical results. The maximum error obtained between the experimental and numerical investigation was found to equal 4.3%
Optimization of CO2 production rate for firefighting robot applications using response surface methodology
A carbon dioxide gas-powered pneumatic actuation has been proposed as a suitable power source for an autonomous firefighting robot (CAFFR), which is designed to operate in an indoor fire environment in our earlier study. Considering the consumption rate of the pneumatic motor, the gas-powered actuation that is based on the theory of phase change material requires optimal determination of not only the sublimation rate of carbon dioxide but also the sizing of dry ice granules. Previous studies that have used the same theory are limited to generating a high volume of carbon dioxide without reference to neither the production rate of the gas nor the size of the granules of the dry ice. However, such consideration remains a design requirement for efficient driving of a carbon dioxide-powered firefighting robot. This paper investigates the effects of influencing design parameters on the sublimation rate of dry ice for powering a pneumatic motor. The optimal settings of these parameters that maximize the sublimation rate at the minimal time and dry ice mass are presented. In the experimental design and analysis, we employed full-factorial design and response surface methodology to fit an acceptable model for the relationship between the design factors and the response variables. Predictive models of the sublimation rate were examined via ANOVA, and the suitability of the linear model is confirmed. Further, an optimal sublimation rate value of 0.1025 g/s is obtained at a temperature of 80°C, the mass of 16.1683 g, and sublimation time of 159.375 s
Association of periodontal and cardiovascular diseases: South-Asian studies 2001-2012
published_or_final_versio
Observations on antifertility and abortifacient herbal drugs
This communication presents first hand information gathered on 36 medicinal plants belonging to 23 families traditionally used by the tribal and rural women of northern areas of North West Frontier Province (NWFP), Pakistan for birth control. Study provides information on local names, mode of administration and dosages as `practiced by rural and tribal women. Most effective plant species to induce abortion include: Artemisia maritime L., Boerhavaia diffusa Auct. Plur., Buddleja asiatica Lour, Chrysanthemum parthenium (L.) Bernh, Justacia adhatod L., Ricinus communis L., Zingiber officinale Roscol., Daucus crota L., Momordica charantia L., Plumbago zeylanica L., Sapindus mukorossi Gaertn., Plantago ovata Forssk, Tanacetum vulgare and Arctium lappa L. The most widely used contraceptives are: Amaranthus viridis L., Achyranthes aspera L., Ricinus communis L., Mentha arvensis L., Nepeta cataria L., Cuscuta reflexa Roxb., Curcuma longa L., Foeniculum vulgare Miller., Butea monosperma (Lam.) O. Kze., Albizia lebbeck (L.) Bth., Ficus religosa L. and Mentha longifolia (L.) Huds. The tribalpopulation of the region primarily depends upon these plants for family planning. They use herbal drugs to induce abortion and as contraceptives. Further studies on chemical and pharmacologicalactions are suggested to validate the claims
Study of serial markers of biological response in rectal cancer patients receiving preoperative chemoradiotherapy with or without biological agents
The key to understanding the heterogeneous behaviour of similar stage locally advance rectal cancer lies in the understanding of tumour biology. The aim of this project was to investigate the biological behaviour of rectal cancers and its alterations in response to neoadjuvant chemoradiotherapy, by studying the intrinsic radiosensitivity, pathophysiology and angiogenesis of rectal cancers. It was intended to provide information that may help risk-stratify patients for individualised treatments including optimal timing of surgery after chemoradiotherapy. Consecutive patients with locally advanced, non-metastatic rectal cancer, who were considered suitable for long-course neoadjuvant chemoradiotherapy, were prospectively recruited. Radiosensitivity was studied by investigating the timing of DNA repair analysis with single cell gel electrophoresis (comet assay). The tumour pathophysiology and angiogenesis was investigated in vivo by novel functional imaging techniques (multiparametric magnetic resonance imaging and dynamic contrast enhanced computed tomography). It is demonstrated that rectal cancer tissue consists of cells with heterogeneous radiosensitivities and functional microvascularity. Until six weeks after NCRT, the DNA repair remains inhibited with progressive devascularisation and increasing hypoxic blood volume resulting in loss of tumour cells. Thereafter, variable fractions of cancer cell may continue to perish or survive with corresponding changes in vascularity. Therefore, the period between the sixth and eleventh weeks after neoadjuvant therapy is a critical time when surviving cells from rectal cancers may develop aggressive traits with long-term consequences. Hence, biological assessment of locally advance rectal cancers after six weeks post-NCRT may help risk-stratify patients for individualised therapy
MANAGEMENT OF ENDOCRINE DISEASE: Hypoparathyroidism in pregnancy: review and evidence-based recommendations for management
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