Running Multiple Instances of the Distributed Coordination Function for Air-time Fairness in Multi-Rate WLANs

Cataloged from PDF version of article.Conventional multi-rate IEEE 802.11 Wireless LANs (WLANs) are associated with the so-called performance anomaly to describe the phenomenon of high bit rate nodes being dragged down by slower nodes. This anomaly is known to be an impediment to obtaining high cumulative throughputs despite the employment of effective link adaptation mechanisms. To cope with the performance anomaly, air-time fairness has been proposed as an alternative to throughput fairness, the latter being a main characteristic of the IEEE 802.11 Distributed Coordination Function (DCF). In this paper, we propose a novel distributed air-time fair MAC (Medium Access Control) without having to change the operation of the conventional DCF. In the proposed MAC, each node in the system runs multiple instances of the conventional DCF back-off algorithm where the number of DCF instances for the nodes can be chosen in a distributed manner. Both analytical and simulation-based results are provided to validate the effectiveness of the proposed air-time fair MAC. © 2013 IEEE

MPLS Automatic Bandwidth Allocation via Adaptive Hysteresis

Cataloged from PDF version of article.MPLS automatic bandwidth allocation (or provisioning) refers to the process of dynamically updating the bandwidth allocation of a label switched path on the basis of actual aggregate traffic demand on this path. Since bandwidth updates require signaling, it is common to limit the rate of updates to reduce signaling costs. In this article, we propose a model-free asynchronous adaptive hysteresis algorithm for MPLS automatic bandwidth allocation under bandwidth update rate constraints. We validate the effectiveness of the proposed approach by comparing it against existing schemes in (i) voice and (ii) data traffic scenarios. The proposed method can also be used in more general GMPLS networks. (C) 2010 Elsevier B.V. All rights reserved

Comparative analysis of image enhancement techniques for uterine fibroid ultrasound

Background: The Ultrasound image is a vital diagnostic tool in the preliminary clinical assessment of many diseases, especially in Obstetrics and Gynecology. However, poor ultrasound image quality often leads to the inaccurate diagnosis of diseases such as uterine fibroids. Many researchers have proposed various methods for improving ultrasound image quality. Objective: To explore by comparison of four image enhancement techniques, the best approach for the enhancement of uterine fibroid images towards achieving better diagnosis and proper management of the disease..Methodology: The study assessed and compared the performance of four (4) different image enhancement techniques namely; Contrast stretching, Gamma correction, Histogram equalization(HE) and Contrast limited adaptive histogram equalization (CLAHE) on uterine fibroid ultrasound image Twenty (20) Ultrasound images from thedatabasewere downloaded and processed in MATLAB (2015a version) using image processing toolbox. Based on histogram distribution and statistical features (Mean, Standard Deviation and Entropy), the enhanced images were evaluated and compared. Results: The results show that Contrast stretching performed better based on Histogram distribution while CLAHE shows superior performance on Statistical featuresConclusion: Contrast stretching and Contrast limited adaptive histogram equalization (CLAHE)have demostrated good performance in enhancement of uterine fibroid ultrasound ima

A novel MEFV gene mutation (A511V) in a Chilean FMF patient

Familial Mediterranean fever (FMF) is an autosomal recessive disease which is characterized by recurrent fever and inflammation of serous membranes. A Chilean FMF patient was investigated for MEFV mutations. After DNA extraction, exons 3, 5, 10 and 30UTR region of MEFV gene were analyzed by DNA sequencing while E148Q and R202Q mutations of exon 2 weredetected by RFLP. A novel missense mutation, A511V (c.1532C>T, p.Ala511Val), was found in a heterozygous state in exon 5 of MEFV gene. Also, R202Q (c.605G>A, p.Arg202Gln) was detected in heterozygous state. R202Q was of clinical value in the diagnosis of FMF when combined with adisease causing mutation. In this patient, A511V was detected in compound heterozygous state with R202Q and this association may play an important role in FMF

Modulation of inducible nitric oxide synthase expression by sumoylation

<p>Abstract</p> <p>Background</p> <p>In astrocytes, the inflammatory induction of Nitric Oxide Synthase type 2 (NOS2) is inhibited by noradrenaline (NA) at the transcriptional level however its effects on specific transcription factors are not fully known. Recent studies show that the activity of several transcription factors including C/EBPβ, which is needed for maximal NOS2 expression, is modulated by conjugation of the small molecular weight protein SUMO. We examined whether the expression of SUMO Related Genes (SRGs: SUMO-1, the conjugating enzyme Ubc9, and the protease SENP1) are affected by inflammatory conditions or NA and whether SUMO-1 regulates NOS2 through interaction with C/EBPβ.</p> <p>Methods</p> <p>Bacterial endotoxin lipopolysaccharide (LPS) was used to induce inflammatory responses including NOS2 expression in primary astrocytes. The mRNA levels of SRGs were determined by QPCR. A functional role for SUMOylation was evaluated by determining effects of over-expressing SRGs on NOS2 promoter and NFκB binding-element reporter constructs. Interactions of SUMO-1 and C/EBPβ with the NOS2 promoter were examined by chromatin immunoprecipitation assays. Interactions of SUMO-1 with C/EBPβ were examined by immunoprecipitation and Western blot analysis and by fluorescence resonance energy transfer (FRET) assays.</p> <p>Results</p> <p>LPS decreased mRNA levels of SUMO-1, Ubc9 and SENP1 in primary astrocytes and a similar decrease occurred during normal aging in brain. NA attenuated the LPS-induced reductions and increased SUMO-1 above basal levels. Over-expression of SUMO-1, Ubc9, or SENP1 reduced the activation of a NOS2 promoter, whereas activation of a 4 × NFκB binding-element reporter was only reduced by SUMO-1. ChIP studies revealed interactions of SUMO-1 and C/EBPβ with C/EBP binding sites on the NOS2 promoter that were modulated by LPS and NA. SUMO-1 co-precipitated with C/EBPβ and a close proximity was confirmed by FRET analysis.</p> <p>Conclusion</p> <p>Our results demonstrate that SUMOylation regulates NOS2 expression in astrocytes, and point to modification of C/EBPβ as a possible mechanism of action. Targeting the SUMOylation pathway may therefore offer a novel means to regulate inflammatory NOS2 expression in neurological conditions and diseases.</p

No significant association between the promoter region polymorphisms of factor VII gene and risk of venous thrombosis in cancer patients

Factor VII (FVII) plays an important role in blood coagulation. The role of common polymorphisms influencing the FVII plasma levels in thromboembolic disorders has been evaluated but there is no published data related to the effect of FVII gene polymorphisms on the venous thrombosis risk in cancer. Aim: To investigate the association of three common functional polymorphisms in the promoter region of FVII gene: a decanucleotide insertion at position-323 (-323ins10-bp), a G to T substitution at position-401 (-401GT), and a G to A substitution at position-402 (-401GT) with venous thrombosis in cancer patients. Materials and Methods: The study included 60 cancer patients with venous thromboembolism (VTE) (group 1) and 130 cancer patients without VTE (group 2). Genotyping of -323ins10-bp, -401GT, and -402GA polymorphisms in the promoter region of FVII gene was performed by the method of single-strand conformation polymorphism analysis and sequencing. Factor V Leiden (FVL) was also determined in all cases. Results: The frequency of FVL was significantly greater in cancer patients with VTE compared with group 2 patients (p 0.05). The results did not change significantly after the exclusion of patients carrying the FVL (p > 0.05). Conclusions: The screening for the -323ins10-bp, -401GT, and -402GA olymorphisms of FVII gene did not contribute to a meaningful diagnostic nvestigation in cancer patients with venous thrombosis

Rate-distortion optimization for stereoscopic video streaming with unequal error protection

We consider an error-resilient stereoscopic streaming system that uses an H.264-based multiview video codec and a rateless Raptor code for recovery from packet losses. One aim of the present work is to suggest a heuristic methodology for modeling the end-to-end rate-distortion (RD) characteristic of such a system. Another aim is to show how to make use of such a model to optimally select the parameters of the video codec and the Raptor code to minimize the overall distortion. Specifically, the proposed system models the RD curve of video encoder and performance of channel codec to jointly derive the optimal encoder bit rates and unequal error protection (UEP) rates specific to the layered stereoscopic video streaming. We define analytical RD curve modeling for each layer that includes the interdependency of these layers. A heuristic analytical model of the performance of Raptor codes is also defined. Furthermore, the distortion on the stereoscopic video quality caused by packet losses is estimated. Finally, analytical models and estimated single-packet loss distortions are used to minimize the end-to-end distortion and to obtain optimal encoder bit rates and UEP rates. The simulation results clearly demonstrate the significant quality gain against the nonoptimized schemes

Effects of Ankaferd Hemostat on Helicobacter pylori strains and antibiotic resistance

Background/aim: Ankaferd hemostat (ABS; Ankaferd blood stopper, Istanbul, Turkey) is a folkloric medicinal plant extract. The aim of this study was to determine the effect of Ankaferd hemostat (ABS) on the fate of Helicobacter pylori strains. The study also aims to determine alterations in the antimicrobial resistance of three different H. pylori strains in response to ABS exposure. Materials and methods: H. pylori Strain 1 was obtained from the culture collection ATCC 43504 and passaged three times for viability. Strain 2 was isolated from a gastric ulcer patient and Strain 3 was isolated from a gastritis patient. 1% of ABS was added to all of the strains and antimicrobial susceptibility was observed on 30 and 60 min after application. Results: The efficacy of ABS solutions in achieving significant logarithmic reduction in foodborne pathogens of H. pylori was observed in this study. This study showed that ABS has antibacterial (Anti-H. pylori) effects. Conclusion: Our present study indicated, for the first time, that ABS could act against H. pylori. ABS is clinically used for the management of GI bleeding due to benign and malignant GI lesions. Thus, the possible anti-H. pylori effect of ABS shall expand the therapeutic spectrum of the drug in GI lesions in relation to H. pylori infection such as peptic ulser disease (PUD) and lymphoid tissue ( MALT) lymphomagenesis

Three-dimensional media for mobile devices

Cataloged from PDF version of article.This paper aims at providing an overview of the core technologies enabling the delivery of 3-D Media to next-generation mobile devices. To succeed in the design of the corresponding system, a profound knowledge about the human visual system and the visual cues that form the perception of depth, combined with understanding of the user requirements for designing user experience for mobile 3-D media, are required. These aspects are addressed first and related with the critical parts of the generic system within a novel user-centered research framework. Next-generation mobile devices are characterized through their portable 3-D displays, as those are considered critical for enabling a genuine 3-D experience on mobiles. Quality of 3-D content is emphasized as the most important factor for the adoption of the new technology. Quality is characterized through the most typical, 3-D-specific visual artifacts on portable 3-D displays and through subjective tests addressing the acceptance and satisfaction of different 3-D video representation, coding, and transmission methods. An emphasis is put on 3-D video broadcast over digital video broadcasting-handheld (DVB-H) in order to illustrate the importance of the joint source-channel optimization of 3-D video for its efficient compression and robust transmission over error-prone channels. The comparative results obtained identify the best coding and transmission approaches and enlighten the interaction between video quality and depth perception along with the influence of the context of media use. Finally, the paper speculates on the role and place of 3-D multimedia mobile devices in the future internet continuum involving the users in cocreation and refining of rich 3-D media content