290 research outputs found

    Enhanced transmission of electromagnetic waves through split-ring resonator-shaped apertures

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    The design of aperture shape is a promising approach for enhanced transmission through a subwavelength aperture. We designed split-ring-resonator (SRR)-shaped apertures in order to increase the transmission through subwavelength apertures by making use of the strong localization of the electromagnetic field in SRR-shaped apertures. We obtained a promising result of 104-fold enhancement by utilizing SRR-shaped apertures. It is possible to use these proposed structures at optical frequencies by making several modifications such as decreasing the sharpness of edges and increasing the gap width. Since SRRs are already being realized at optical frequencies, our proposed SRR-shaped aperture structures are promising candidates for novel applications

    Surgical Planning and Additive Manufacturing of an Anatomical Model: A Case Study of a Spine Surgery

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    3D scanning technologies have promising solutions for medical needs such as anatomical models, biocompatible implants, and orthotic/prosthetic models. Although virtual presurgical planning offers more precise results, it may not be applied in every hospital because of the high costs. The aim of this study is to assess the accuracy of the suggested low-cost and effective surgical planning method by means of additive manufacturing to increase success rate of each surgery. In this study, a full spine model of a scoliosis patient was acquired and reconstructed in MIMICS software using different filters and parameters. Therefore, a comparison in terms of geometrical errors among each model was performed based on a reference model. Subsequently, patient-specific full spine model was manufactured using a three-dimensional printing method (fused deposition modeling) and utilized before the surgery. 3D surgical model reconstruction parameters such as wrap tool, binomial blur, and curvature flow filters produced high geometrical errors, while mean filter produced the lowest geometrical error. Furthermore, similarity results of the curvature flow and discrete Gaussian filters were close to mean filter. Smooth tool and mean filter produced almost the same volume of the reference model. Consequently, an ideal protocol for surgical planning of a spine surgery is defined with measurable accuracy. Thus, success rate of a spine surgery may be increased especially for the severe cases owing to the more accurate preoperative review: operability

    Microscopic and molecular detection of Nosema spp. in honeybees of Turkey

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    International audienceAbstractIn this study, we aimed to determine the prevalence of Nosema spp. in honeybees of Turkey. For this aim, adult honeybee (Apis mellifera) samples were collected from 1621 colonies within 95 apiaries located in 22 provinces of Turkey. Samples were examined microscopically. In case of positivity, spore identification was done by multiplex PCR. At the end of microscopic examination, Nosema spp. spores were detected in 7 out of 22 provinces (31.8 %), and 16 out of 95 colonies (16.8 %) that represent 1621 colonies. According to PCR results, 1 out of 16 isolates (6.25 %) was Nosema apis, and 15 out of 16 isolates (93.75 %) were Nosema ceranae. The result of our study indicated that N.ceranae is the dominant species in Turkey

    Influence of infliximab pretreatment on ischemia/reperfusion injury in rat intestine

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    The Pringle maneuver is used in hepatic surgery to prevent blood loss but is associated with ischemia- reperfusion injury. To investigate the effect of infliximab on inflammation and apoptosis in rat intestinal mucosa during ischemia-reperfusion (IR) injury. A total of 30 male Wistar albino rats were equally divided into three groups to be subjected to (i) sham operation (sham), (ii) IR injury via Pringle maneuver (pringle) or (iii) infliximab (IFX) group (IFX was given at a dose 3 mg/kg for 3 days before IR injury). Following reperfusion period of 60 min., intestinal tissue and blood samples were taken and processed by standard histological methods. The Pringle maneuver and following reperfusion caused significant histopathological changes, increased serum transaminases’ activity and the levels of oxidative stress markers and decreased glutathione peroxidase activity. IFX pretreatment partially prevented these changes. Infliximab pretreatment may protect intestinal mucosa against ischemia-reperfusion injury. Further studies are needed to investigate mechanism and evaluate safety and optimal dosing of IFX in humans exposed to the possible tissue damage by ischemia-reperfusion. (Folia Histochemica et Cytobiologica 2014, Vol. 52, No. 1, 36–41

    Hypothetical study of small hive beetle aethina tumida infestation in honeybees, risk commodities and probabilities for its introduction in türkiye

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    Türkiye is the second-largest honey producer globally; however, the export of honey and bee products does not adequately support the beekeeping industry. Pests account for the largest share of expenditure for agents found in honeybees in the country. Although the Small Hive Beetle (SHB) has not been detected in Türkiye, a risk assessment was performed to determine what happens if it enters the country. The risk assessment included: a) hazard identification; b) risk pathway determination; c) risk assessment for entry via the identified pathways; and d) outcome assessment for becoming endemic in Türkiye. The Risk AMP add-in program was used to assess the probability of distribution for each method of entry, pathway, and simulation. According to the simulations, the probability of SHB introduction in Türkiye varies from 0.17 per 1000 events/days (1.7 per 10000 days or 27 years) to 0.6 per 1000 events/imports (6 per 10000 days or 27 years). The highest likelihood of introduction comes from fruit import (11/15) and soil/compost import (4/15). The mean probability of introducing SHB infestation after 1000 iterations of the constructed model is 0.37 per 1000 events/days (3.7 within 10000 days or 27 years). Finally, the simulated average cost of SHB after the possible introduction is 523 million US $ for Türkiye. With these simulated data, risk assessment of a non-detected pest, SHB, was determined for Türkiye

    Split ring resonator-coupled enhanced transmission through a single subwavelength aperture

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    We report the enhanced transmission of electromagnetic waves through a single subwavelength aperture by making use of the resonance behavior of a split ring resonator (SRR) at microwave frequencies. By placing a single SRR at the near-field of the aperture, strongly localized electromagnetic fields are effectively coupled to the aperture with a radius that is twenty times smaller than the resonance wavelength. We obtained 740-fold transmission enhancement by exciting the electric resonance of SRR. A different coupling mechanism, through the magnetic resonance of SRR, is also verified to yield enhanced transmission. Good agreement is obtained between the microwave measurements and numerical simulations.Comment: 14 pages, 4 figures, to be submitted to PR

    Congenital partial arhinia: a case report

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    Congenital arhinia is an extremely rare anomaly consisting of an absence of external nasal structures and nasal passages. Fewer than 30 cases have been reported. Patients with a familial absence of the nose have been reported, but the effects of genetic and maternal factors are unknown. Midface hypoplasia may accompany arhinia. Accompanying malformations are thought to be caused by an absent or rudimentary nose. A patient with partial congenital arhinia is presented and the embryology and literature review are discussed
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