396 research outputs found

    Energy efficient random sleep-awake schedule design

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    This letter presents a simple model for determining energy efficient random sleep-awake schedules. Random sleepawake schedules are more appropriate for sensor networks, where the time of occurrence of an event being monitored, e.g., the detection of an intruder, is unknown a priori, and the coordination among nodes is costly. We model the random sleepawake schedule as a two state Markov process, and maximize the probability of the transmission of sensed data by a given deadline. Our results indicate that for a given duty cycle, the optimal policy is to have infrequent transitions between sleep and awake modes, if the average number of packets sent is greater than the mean number of slots the node is awake

    Controlling the charge transfer flow at the graphene/pyrene-nitrilotriacetic acid interface

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    The fabrication of highly efficient bio-organic nanoelectronic devices is still a challenge due to the difficulty in interfacing the biomolecular component to the organic counterparts. One of the ways to overcome this bottleneck is to add a self-assembled monolayer (SAM) in between the electrode and the biological material. The addition of a pyrene-nitrilotriacetic acid layer to a graphene metal electrode enhances the charge transfer within the device. Our theoretical calculations and electrochemical results show that the formation of a pyrene-nitrilotriacetic acid SAM enforces a direct electron transfer from graphene to the SAM, while the addition of the Ni2+ cation and imidazole reverses the charge transfer direction, allowing an atomic control of the electron flow, which is essential for a true working device. © 2018 The Royal Society of Chemistry

    Crystal and electronic structure study of Mn doped wurtzite ZnO nanoparticles

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    AbstractThe change in the crystal and electronic structure properties of wurtzite ZnO nanoparticles was studied according to Mn doping in the powder samples. The investigations were conducted by X-ray Absorption Fine Structure Spectroscopy (XAFS) technique for the samples prepared with different heating and doping processes. Electronic analysis was carried out by the collected data from the X-ray Absorption Near-Edge Structure Spectroscopy (XANES) measurements. Additional crystal structure properties were studied by Extended-XAFS (EXAFS) analysis. Longer heating periods for the undoped wurtzite ZnO samples were determined to own stable crystal geometries. However, for some doped samples, the distortions in the crystal were observed as a result of the low doping amounts of Mn which was treated as an impurity. Besides, the changes in oxygen locations were determined to create defects and distortions in the samples

    Association between health literacy and medication adherence in the elderly population with chronic disease

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    Background: Medication adherence is a key factor in the therapy of chronic diseases in older people. It is important to investigate the effect of health literacy on medication adherence in this patient population. Health literacy can be summarized as an individual’s ability to understand and interpret the provided medical information and to behave appropriately based on this information. Aim: The purpose of this study was to investigate the association between health literacy and medication adherence in older people with chronic disease. Methods: A total of 175 patients admitted to the family health center clinic in Bursa, Turkey, who were older than 65 years old, were enrolled in this cross-sectional study using the convenience sampling method. A priori power analysis was conducted to determine the required sample size to reach 90% power. The Turkish version of the 8-item Morisky Medication Adherence Scale (MMAS-8) was used to assess medication adherence. The European Health Literacy Survey Questionnaire (HLS-EU-Q47) was used to evaluate health literacy. Disability associated with dyspnea was assessed using the Medical Research Council (MRC) dyspnea scale. Results: The data showed that, according to dyspnea status and diagnosis, medication adherence varied. In this sample, medication adherence in elderly patients was not associated with health literacy. Instead, medication adherence was associated with the patient’s disability and the course of the disease. Discussion and conclusions: Improving health literacy may enhance the medication adherence of older people with chronic disease. The development, practice and evaluation of health literacy interventions for older people with chronic conditions are important to increase medication adherence and potentially improve patient outcomes. [Ethiop. J. Health Dev. 2020; 34(2):90-96] Key words: Health literacy, medication adherence, older patients, chronic disease, dyspne

    Improving network reliability by exploiting path diversity in ad hoc networks with bursty losses

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    In wireless mobile ad hoc networks, end-to-end connections are often subject to failures which do not make the connection non-operational indefinitely but interrupt the communication for intermittent short periods of time. These intermittent failures usually arise from the mobility of hosts, dynamics of the wireless medium or energy-saving mechanisms, and cause bursty packet losses. Reliable communication in this kind of an environment is becoming more important with the emerging use of ad hoc networks for carrying diverse multimedia applications such as voice, video and data. In this thesis, we present a new path reliability model that captures intermittent availability of the paths, and we devise a routing strategy based on our path reliability model in order to improve the network reliability. Our routing strategy takes the advantage of path diversity in the network and uses a diversity coding scheme in order not to compromise efficiency. In diversity coding scheme, if the original information is encoded by using a (N,K) code, then it is enough for the destination to receive any K bits correctly out of N bits to successfully decode the original information. In our scheme, the original information is divided into N subpackets and subpackets are distributed among the available disjoint paths in the network. The distribution of subpackets among the diverse paths is a crucial decision. The subpackets should be distributed 'intelligently' so that the probability of successful reconstruction of the original information is maximized. Given the failure statistics of the paths, and the code rate (N, K), our strategy determines the allocation of subpackets to each path in such a manner that the probability of reconstruction of the original information at the destination is maximized. Simulation results justify the accuracy and efficiency of our approach. Additionally, simulation results show that our multipath routing strategy improves the network reliability substantially compared to the single path routing. In wireless networks, a widely used strategy is to place the nodes into a low energy consuming sleep mode in order to prolong the battery life. In this study, we also consider the cases where the intermittent availability of the nodes is due to the sleep/awake cycles of wireless nodes. A sleep/awake scheduling strategy is proposed which minimizes the packet latency while satisfying the energy saving ratio specified by the energy saving mechanism

    Feasibility of 3-dimensional sampling perfection with application optimized contrast sequence in the evaluation of patients with hydrocephalus

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    Purpose This study aimed to investigate the effectiveness and additive value of T2W 3-dimensional sampling perfection with application optimized contrast (3D-SPACE) with variant flip-angle mode in imaging of all types of hydrocephalus. Our secondary objective was to assess the reliability of 3D-SPACE sequence and correspondence of the results with phase-contrast magnetic resonance imaging (PC-MRI)-based data. Materials and Methods Forty-one patients with hydrocephalus have undergone 3-T MRI. T2W 3D-SPACE sequence has been obtained in addition to routine hydrocephalus protocol. Cerebrospinal fluid circulation, presence/type/etiology of hydrocephalus, obstruction level scores, and diagnostic levels of confidence were evaluated separately by 2 radiologists. In the first session, routine sequences with PC-MRI were evaluated, and in another session, only 3D-SPACE and 3-dimensional magnetization prepared rapid acquisition gradient echo sequences were evaluated. Results obtained in these sessions were compared with each other and those obtained in consensus session. Results Agreement values were very good for both 3D-SPACE and PC-MRI sequences (P < 0.001 for all). Also, the correlation of more experienced reader's 3D-SPACE-based scores and consensus-based scores was perfect (κ = 1, P < 0.001).The mean value of PC-MRI-based confidence scores were lower than those obtained in 3D-SPACE and consensus sessions. Conclusions T2W 3D-SPACE sequence provides morphologic cerebrospinal fluid flow data. It is a noninvasive technique providing extensive multiplanar reformatted images with a lower specific absorption rate. These advantages over PC-MRI make 3D-SPACE sequence a promising tool in management of patients with hydrocephalus. © 2015 Wolters Kluwer Health, Inc

    Eocene metatherians from Anatolia illuminate the assembly of an island fauna during Deep Time

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    Island biotas have disproportionately influenced the history and development of evolutionary biology, but understanding their genesis and evolution across geological timescales has been hindered by a poor fossil record. Here we augment the insular Eocene (~43 Ma) mammalian fauna known from the Pontide terrane of central Anatolia by describing two new metatherian taxa (stem marsupials) from the Lu¨ lu¨k Member of the Uzunc¸arşıdere Formation in the Orhaniye Basin. Geological and paleontological data indicate that the Pontide terrane was an island on the northern margin of Neotethys during the middle Eocene. Reflecting its geodynamic context in a region of active tectonic convergence, the Eocene Pontide terrane hosted a unique combination of Laurasian and Gondwanan mammals, including an anachronistic radiation of pleuraspidotheriids (archaic ungulates) that went extinct on the European mainland ~13 Ma earlier. Most of the mammalian clades occupying the Pontide terrane colonized it by dispersal across marine barriers rather than being stranded there through vicariance. Endemic radiations of pleuraspidotheriid ungulates and polydolopimorphian metatherians on the Pontide terrane reveal that in situ diversification was an important factor contributing to faunal assembly and evolution. The insular fauna that arose on the Pontide terrane is highly analogous to that of modern Sulawesi, which evolved under strikingly similar geological conditions. Illustrating the ephemeral nature of insular biotas across macroevolutionary timescales, the demise of the Pontide fauna coincided with paleogeographic changes enabling more cosmopolitan taxa to reach it for the first time. The high level of endemism shown by the mammalian fauna of the Uzunc¸arşıdere Formation eliminates the Pontide terrane as a potential early Eocene dispersal corridor between western Europe and India.INSU-2011 CT49215-12W296-13EAR- 154368

    Selective Photokilling of Human Pancreatic Cancer Cells Using Cetuximab-Targeted Mesoporous Silica Nanoparticles for Delivery of Zinc Phthalocyanine

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    Background: Photodynamic therapy (PDT) is a non-invasive and innovative cancer therapy based on the photodynamic effect. In this study, we sought to determine the singlet oxygen production, intracellular uptake, and in vitro photodynamic therapy potential of Cetixumab-targeted, zinc(II) 2,3,9,10,16,17,23,24-octa(tert-butylphenoxy))phthalocyaninato(2-)-N29,N30,N31,N32 (ZnPcOBP)- loaded mesoporous silica nanoparticles against pancreatic cancer cells. Results: The quantum yield (Φ∆) value of ZnPcOBP was found to be 0.60 in toluene. In vitro cellular studies were performed to determine the dark- and phototoxicity of samples with various concentrations of ZnPcOBP by using pancreatic cells (AsPC-1, PANC-1 and MIA PaCa-2) and 20, 30, and 40 J/cm2 light fluences. No dark toxicity was observed for any sample in any cell line. ZnPcOBP alone showed a modest photodynamic activity. However, when incorporated in silica nanoparticles, it showed a relatively high phototoxic effect, which was further enhanced by Cetuximab, a monoclonal antibody that targets the Epidermal Growth Factor Receptor (EGFR). The cell-line dependent photokilling observed correlates well with EGFR expression levels in these cells. Conclusions: Imidazole-capped Cetuximab-targeted mesoporous silica nanoparticles are excellent vehicles for the selective delivery of ZnPcOBP to pancreatic cancer cells expressing the EGFR receptor. The novel nanosystem appears to be a suitable agent for photodynamic therapy of pancreatic tumor

    The Research of Sleep Disorders and Their Effects on Quality of Life in Patients with Chronic Renal Failure and Renal Transplant

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    Objective End stage renal insufficiency (ESRI) is defined as the irreversible loss of renal functions. In its treatment is used hemodialisis, peritoneal dialisis or renal transplantation. Sleep disorders cause excesive daytime sleepiness, mental problems, dysfunction in general health and functions; and therefore affect the quality of life in patients with ESRI. In this study is evaluated the relationship between sleep quality and the qulity of life in patients with hemodialisis, peritoneal dialisis and renal transplantation. Materials and Methods A total of 117 patients being treated in Uludağ University Faculty of Medicine Dialisis Unit between years 2011-2012 were enrolled. Pittsburg Sleep Quality Index (PSQI) were used to determine sleep quality of patients, and Epworth Sleepiness Scale (EUS) and Rolls Royce Quality of Life Scale were used. Results In PSQI, poor sleep quality was observed in 81.5% of patients with hemodialisis, which was 80.8% in patients with renal transplantation and 82% in patients with peritoneal dialisis. In Rolls-Royce Quality of life scale, general health, physical symptoms and activities were higher in patients with renal transplantation, and sleep disorders were higher in patients with hemodialisis. Conclusion Chronic renal insufficiency is a very common condition. Sleep disorders in these patients may affect self-care and show a negative influence on the quality of life. Fort his reason, sleep disorders should be questioned and treated in these chronically ill patients with ESRI
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