1,607 research outputs found

    On Security and reliability using cooperative transmissions in sensor networks

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    Cooperative transmissions have received recent attention and research papers have demonstrated their benefits for wireless networks. Such benefits include improving the reliability of links through diversity and/or increasing the reach of a link compared to a single transmitter transmitting to a single receiver (single-input single-output or SISO). In one form of cooperative transmissions, multiple nodes can act as virtual antenna elements and provide diversity gain or range improvement using space-time coding. In a multi-hop ad hoc or sensor network, a source node can make use of its neighbors as relays with itself to reach an intermediate node with greater reliability or at a larger distance than otherwise possible. The intermediate node will use its neighbors in a similar manner and this process continues till the destination is reached. Thus, for the same reliability of a link as SISO, the number of hops between a source and destination may be reduced using cooperative transmissions as each hop spans a larger distance. However, the presence of ma-licious or compromised nodes in the network impacts the benefits obtained with cooperative transmissions. Using more relays can increase the reach of a link, but if one or more relays are malicious, the transmission may fail. However, the relationships between the number of relays, the number of hops, and success probabilities are not trivial to determine. In this paper, we analyze this problem to understand the conditions under which cooperative transmissions fare better or worse than SISO transmissions. We take into consideration additional parameters such as the path-loss exponent and provide a framework that allows us to evaluate the conditions when cooperative transmissions are better than SISO transmissions. This analysis provides insights that can be employed before resorting to simulations or experimentation. © Springer Science+Business Media, LLC 2012

    Structure of the exportin Xpo4 in complex with RanGTP and the hypusine-containing translation factor eIF5A.

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    Xpo4 is a bidirectional nuclear transport receptor that mediates nuclear export of eIF5A and Smad3 as well as import of Sox2 and SRY. How Xpo4 recognizes such a variety of cargoes is as yet unknown. Here we present the crystal structure of the RanGTP·Xpo4·eIF5A export complex at 3.2 Å resolution. Xpo4 has a similar structure as CRM1, but the NES-binding site is occluded, and a new interaction site evolved that recognizes both globular domains of eIF5A. eIF5A contains hypusine, a unique amino acid with two positive charges, which is essential for cell viability and eIF5A function in translation. The hypusine docks into a deep, acidic pocket of Xpo4 and is thus a critical element of eIF5A’s complex export signature. This further suggests that Xpo4 recognizes other cargoes differently, and illustrates how Xpo4 suppresses – in a chaperone-like manner – undesired interactions of eIF5A inside nuclei

    Macroanatomical and histological study of the structure of intercornual gland in Abaza (Capra Aegagrus) and Gurcu (Capra Falconeri) goats breeds

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    Background: The anatomical localisation of the odour glands, which increase activity during the reproduction period and help goat species to find each other, varies. Materials and methods: In our study, the anatomical and histological structures of the glands around the horn were examined in the Gurcu and Abaza goats, which are native breeds. In this study a total of 12 Abaza and Gurcu goat heads were used. Results: The area between the two horns and area at the back of the horns were shaved to remove all hair. The distance between the horns of both goat breeds was measured using an electronic calliper. The mean distance between the horns of the Abaza goats was determined as 36.80 ± 8.62 mm while this distance was 39.63 ± 4.10 mm for the Gurcu goats. Gland tissue that could not be seen anatomically under the skin was examined histologically. For the histological examination, skin samples were taken from the anterior, middle, right posterior and left posterior of the area between the two horns of both breeds. Crossman triple staining and haematoxylin and eosin staining were applied to the samples. Conclusions: Glandula intercornualis was found to be slightly caudal between the horns in both breeds and normal sebaceous glands were almost absent in the areas where these glands were found. Lobes and branched alveolar glands were located around the hair follicles

    The prognostic relationship of 18F-FDG PET/CT metabolic and volumetric parameters in metastatic ALK plus NSCLC

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    ObjectiveThe aim of this study is to determine the role of metabolic and volumetric parameters obtained from 18Fluorine-Fluorodeoxyglucose PET/computed tomography (18F-FDG PET/CT) imaging on progression-free survival (PFS) and overall survival (OS) in patients with advanced nonsquamous cell lung carcinoma (NSCLC) with anaplastic lymphoma kinase (ALK) rearrangement.MethodsPre and post-treatment PET/CT images of the ALK + NSCLC patients between January 2015 and July 2020 were evaluated. The highest standardized uptake value (SUVmax), metabolic tumor volume (MTV) and total lesion glycolysis (TLG) values were obtained from pre-tyrosine kinase inhibitor (TKI) basal PET/CT (PETpre) and post-TKI PET/CT (PETpost) images. Total MTV (tMTV) and total TLG (tTLG) values were calculated by summing MTV and TLG values in all tumor foci. The change (Delta) in pSUVmax, pMTV, pTLG, tMTV and tTLG before and after treatment was calculated.The relationship of these parameters with OS and PFS was analyzed.ResultstTLG(pre), tMTV(pre), pTLG(pre), pMTV(pre), increment SUVmax, increment tMTV and increment tTLG values were found to be associated with OS; increment tMTV, increment tTLG, tTLG(pre), tMTV(pre), pTLG(pre) and pMTV(pre) were associated with PFS. The cutoff values in both predicting OS and PFS were calculated as -31.6 and 391.1 for increment tMTV and tTLG(pre), respectively. In Cox regression analysis, increment tMTV and stage for OS and increment tMTV and tTLGpre for PFS were obtained as prognostic factors.ConclusionsMetabolic and volumetric parameters, especially TLG values in the whole body before treatment and change in whole body MTV value, obtained from PET/CT may be useful in predicting prognosis and determining treatment strategies for patients with advanced ALK + NSCLC

    Suprascapular foramen: a rare variation caused by ossified suprascapular ligaments

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    Background: The aim of this study was to investigate the incidence of the suprascapular foramen in West Anatolian population. Materials and methods: Eighty-one dried human scapulae of West Anatolian people of unknown ages and gender belonging to the Anatomy Department Laboratory of Dokuz Eylul University Medical School were examined macroscopically. The vertical and transverse diameters of the suprascapular foramen and central thickness of the ossified ligaments were measured with calliper in millimetres and digital calliper, respectively. Results: We observed the suprascapular foramen due to ossification of the suprascapular ligament only in 2 of 81 (2.47%) scapulae. The vertical and transverse diameters of the suprascapular foramen and central thickness of the ossified ligaments (No. 1 and No. 2) were measured as 8.0 mm vs. 4.0 mm, 3.6 mm vs. 2.0 mm and 4.0 mm vs. 1.4 mm, respectively. Conclusions: The suprascapular foramen caused by ossified suprascapular ligament is rarely observed variation in West Anatolian population.
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