92 research outputs found

    Assessment of paranasal sinus parameters according to ancient skulls’ gender and age by using cone-beam computed tomography

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    Background: The aim of this study was to determine whether paranasal sinus dimensions and volume can be useful to identify gender and age estimation for ancient skulls using cone-beam computed tomography (CBCT) images.  Materials and methods: CBCT scans of 32 ancient skulls of approximately 1000 years of age were included in this retrospective study. The gender and age estimation of the skulls were made by an independent anthropologist, which was considered as the gold standard. Paranasal sinuses’ dimensions (width and height) and volumes of each sinus were measured from the CBCT data set that was linked to the three-dimensional rendering software (Anatomage, Invivo 5.2). All measurements were performed by an independent observer. Intra-observer analysis was made. Mann-Whitney and Kruskal-Wallis tests were used to compare paranasal sinus parameters in terms of age estimation and gender (p < 0.05).  Results: The results demonstrated no statistically significant difference between measurements (p < 0.05). The measurements were found to be highly reprodu- cible. The mean volumes of frontal and sphenoid sinus were found to be higher in males. The distance from anterior-posterior wall of sphenoid sinus in axial sec- tions is larger in males (p > 0.05). The frontal sinus width and volume increased statistically with age above 60 years of age (p > 0.05).  Conclusions: The paranasal volume and dimensions’ measurements from CBCT data can be a promising technique to determine gender and age of ancient skulls because of its lower voxel sizes and higher resolution.

    Anatomical characteristics of the lingual foramen in ancient skulls: a cone beam computed tomography study in an Anatolian population

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    Background: The purpose of this study is to evaluate the anatomical features of lingual foramina and their bony canals in Anatolian ancient mandibles (9–10th century) by using cone beam computed tomography (CBCT). Materials and methods: Fifty-eight ancient dry mandibles were scanned with CBCT. Lingual foramina were grouped into midline, paramedian, posterior foramina and combination of these groups. Midline group was also classified according to internal surface of the mandible (gonial tubercles [GTs]). The incidence, vertical distance and diameter of lingual foramina were measured according to age groups and gender. Results: The incidence of the lingual foramen was 96.6%. Midline of the symphysis had the highest incidence (34.4%) of foramina (p < 0.05), followed by both midline and paramedian type (32.8%; p < 0.05). Classification in terms of GT represented class 3 as the most encountered group (28.6%). Number of foramina observed in the mandibles ranged from 0 to 6 with the incidence of 3.4% and 32.8%, respectively. The male and < 35 years groups presented larger measurement values in midline region (p < 0.05). Conclusions: Mandibular lingual foramina and bony canals are frequently present in ancient mandibles. When compared with modern subjects, similar findings are observed according to published literatures. CBCT is also proved to be an effective imaging modality in the detection of lingual foramina and canals in anthropological studies

    Efecto de annealing sobre las propiedades estructurales, térmicas y mecánicas de la composición de aleación binaria Al85 Ni 15

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    Introduction: The Al 85-Ni15 alloy with 99.99% purity of Al and Ni were prepared by an arc melting technique system. The annealing effect onthe microstructure properties, phase transformation and micro-hardness for the Al-Ni alloy system were investigated. Material and Methods:The alloys were characterized by X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), and Differential Thermal Analysis (DTA) as well as Vickers micro-hardness measurement. Results and Discussion: The quantitative results confirm that the chemical composition of the alloys is very close to compositions and the microstructures are in typical lamellar morphology. Mechanical properties for the as-prepared samples and subsequently heat-treated samples were measured by a Vickers indenter. Values of the micro-hardness (HV) Conclusions: According the XRD pattern analysis a multi phases produced, such as Al, AlNi3in room temperature, Al3Ni2, Al0.42Ni0.58 at 200ºC, Al1.1Ni0.9 at 300ºC and Al 0.802Ni0.198, AlNi3 and AlNi at 400ºC, and Al0.802Ni0.198, AlNi3 and AlNi for 500ºC. Similar approached were obtained from the results of SEM and DTA measurements. Annealing treatments are visibly affecting the alloy phase formation with different phases at different temperature. and the elastic modulus (E) of the as prepared sample are 132.9±0.1 kgfmm-2 (1.329±0.1 GPa) and 80.340±0.1 GPa, respectively. Furthermore, the characteristic of the materials plasticity (δH) value was calculated to be 0.85. The micro-hardness values are decrease with the increase of annealing temperatures

    Delayed diagnosis of oral squamous cell carcinoma: a case series

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    <p>Abstract</p> <p>Introduction</p> <p>In malign neoplasms, oral cancer is one of the important causes of mortality and morbidity. Squamous cell carcinoma is the most common form of oral cancers in adults and is related to risk factors such as smoking and alcohol consumption.</p> <p>Case presentation</p> <p>In this article, we present three case reports of oral squamous cell carcinomas with delayed diagnosis. The first patient was a 52-year-old Turkish man, the second patient was a 61-year-old Turkish man and the third patient was a 60-year-old Turkish woman. All were referred to the Ankara University Faculty of Dentistry with pain, swelling and various complaints in their jaws.</p> <p>Conclusion</p> <p>Early diagnosis is of vital importance for the prognosis of the patients with oral squamous cell carcinomas. For this reason, dentists play a crucial role in the early detection and prevention of oral cancers.</p

    Single-molecule correlated chemical probing of RNA

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    RNA molecules function as the central conduit of information transfer in biology. To do this, they encode information both in their sequences and in their higher-order structures. Understanding the higher-order structure of RNA remains challenging. In this work we devise a simple, experimentally concise, and accurate approach for examining higher-order RNA structure by converting widely used massively parallel sequencing into an easily implemented single-molecule experiment for detecting through-space interactions and multiple conformations. We then use this experiment to analyze higher-order RNA structure, detect biologically important hidden states, and refine accurate three-dimensional structure models

    Wpływ procesów obróbki wstępnej na sprawność przenoszenia sygnału tekstylnych linii transmisyjnych

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    Transmission lines in the textile structure are a path of supplying power or transmitting digital/analog signals to electronic components in a textronic system. The current experimental investigation concerned potential differences in the signal transferring capability of textile transmission lines that were subjected to different pretreatment processes. In this study, 11 conductive yarns (stainless steel, silver plated PA and insulated copper) with different linear resistance values were used to create transmission lines through different weave patterns. E-fabric structures containing transmission lines were subjected to combined desizing, alkaline scouring and hydrogen peroxide bleaching pretreatment processes. Signal-to-noise measurements were performed before and after each pretreatment process. In order to make any reasonable comparison of the signal transferring capability of efabric samples, recorded signals were analysed using Matlab ® and their SNR values were also compared statistically. The results show that the pretreatment processes, the linear resistance of conductive yarns and the type of weave structure significantly influence the signal transferring capability of the transmission lines.Linie transmisyjne w strukturze tekstylnej są ścieżką zasilania lub przesyłania sygnałów analogowych/cyfrowych do komponentów elektronicznych w tekstronice. Badania eksperymentalne dotyczą potencjalnych różnic w sprawności przenoszenia sygnału tekstylnych linii transmisyjnych, które zostały poddane różnym procesom obróbki wstępnej. W pracy zastosowano 11 przędz przewodzących o różnych wartościach oporu liniowego wykonanych ze stali nierdzewnej, posrebrzanego poliamidu i izolowanych drutów miedzianych. Przędze te wykorzystano do stworzenia linii transmisyjnych poprzez zastosowanie różnych splotów tkackich. Struktury tkanin zawierających linie transmisyjne poddano procesom: usuwania klejonki, obróbki alkalicznej i bielenia nadtlenkiem wodoru. Przed i po każdym procesie obróbki wstępnej dokonano pomiarów zakłóceń. W celu porównania sprawności przenoszenia sygnału zarejestrowane sygnały były analizowane i porównane statystycznie. Wyniki pokazują, że procesy obróbki wstępnej, opór liniowy przędz przewodzących oraz typ splotu mają istotny wpływ na sprawność przenoszenia sygnału tekstylnych linii transmisyjnych

    Identification and Modeling of Sensing Capability of Force Sensing Resistor Integrated to E-Textile Structure

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    Simulation Of A Rectangular Cylinder In Cross Flow In A Microchannel Using Information Preservation (Ip) Method

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    A numerical simulation is performed to study the characteristics of the gas flow over a constant temperature rectangular cylinder in a cross flow in a micro channel. The non-isothermal Information Preservation (IP) method is employed to eliminate the statistical scatter of Direct Simulation Monte Carlo (DSMC) at low Reynolds numbers. Pressure boundary conditions based on the characteristic theory are implemented in the algorithm. The simulation results are compared with the references available in the literature. This study will form a base for our future particle-atomistic hybrid computations. Copyright © 2007 by ASME

    Simulation Of Low Speed Gas Flow Over Backward Facing Step In Microchannels

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    Proper design of thermal management solutions for future nano-scale electronics or photonics will require knowledge of flow and transport through micron-scale ducts. As in the macro-scale conventional counterparts, such micron-scale flow systems would require robust simulation tools for early-stage design iterations. This paper concentrates on such a flow process, namely pressure-driven gas flow over a backward facing step in a microchannel. A well-known particle-based method, Direct Simulation Monte Carlo (DSMC) is used as the simulation tool. Separating the macroscopic velocity from the molecular velocity through the use of the Information Preservation (IP) method eliminates the high-level of statistical noise as typical in DSMC calculations of low-speed flows. The non-isothermal IP method is further modified to incorporate the pressure boundary conditions, which are expected to be more prevalent in design of thermal management systems. The applicability of the method in solving a real flow situation is verified using the backward facing step flow in a micro geometry. The flow and heat transfer mechanisms at different pressures in Knudsen transient regime are investigated. The range of parameters for this investigation are: Re from 0.03 to 0.64, Ma from 0.013 to 0.083, and Kn from 0.24 to 4.81, all based on maximum values. Copyright © 2006 by ASME
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