599 research outputs found
Comparison of the calculated absorption and the measured field strength of HF waves reflected from the ionosphere
The absorption (L) of the wave in the ionosphere has been calculated. The 5.47MHz wave is transmitted from Ercis, Turkey (39.03°N, 43.37°E)and received at Elazıg, Turkey (38.70°N, 39.20°E). The field strength of this wave is measured by ITU-Compliant HF Field Strength Monitoring Terminal, and the absorption L in the ionosphere has been calculated. It is observed that the field strength of the wave is least around noon time and it increases at night times at all seasons. The diurnal and seasonal variations of the calculated absorption L shows that the maximum absorption in the wave occurs around noon time. The behaviour of the diurnal and seasonal variations of the field strength of the wave can be explained with the diurnal and seasonal variations of the calculated absorption L in the ionosphere. Equation (22) in this paper can be used to obtain the imaginary part (β) of the refractive index of the ionospheric plasma, and it can be applied to the HF radio waves propagations in the ionosphere for absorption L
Esterase variation in Turkish white-toothed shrews (Crocidura): Record of a trimeric esterase
This study focuses on esterase variation of the genus Crocidura in Turkey. A total of 248 white-toothed shrews were analyzed by means of cellulose acetate gel electrophoresis. Liver tissue and alfa naphthyl acetate were used to investigate esterase variation in Turkish white-toothed shrews. A different esterase banding pattern was found in one Crocidura individual. This phenotype had four anodally migrated bands on cellulose acetate gel. The Crocidura individual displaying the given phenotype was identified as Crocidura suaveolens. The different esterase banding pattern observed in this study is considered to be a result of the trimeric structure of esterase in the lesser white-toothed shrew (Crocidura suaveolens)
Electrochemical cardiac troponin I immunosensor based on nitrogen and boron-doped graphene quantum dots electrode platform and Ce-doped SnO2/SnS2 signal amplification
The detection of acute myocardial infarction directly depends on the concentration of the cardiac troponin I (CTnI) in human blood plasma. In this study, the sensitive, selective, and fast sandwich-type electrochemical CTnI immunosensor was developed by using nitrogen and boron-dopped graphene quantum dots -as electrode platform and two-dimensional Ce-dopped SnO2/SnS2 (Ce–SnO2/SnS2) as signal amplification. In preparation of electrochemical CTnI immunosensor, the coordinated covalent bond between capture antibody (anti-CTnI-Ab1) and nitrogen and boron-dopped graphene quantum dots as electrode platform led to immobilization of anti-CTnI-Ab1, and the strong esterification between the secondary antibody (anti-CTnI-Ab2) and thioglycolic acid-modified Ce–SnO2/SnS2 resulted in anti-CTnI-Ab2 conjugation. Finally, the resultant electrochemical CTnI immunosensor was formed via antigen-antibody interaction. High-resolution transmission electron microscopy, X-ray photoelectron spectroscopy, X-ray diffraction, Fourier transform infrared spectroscopy, UV–Vis spectroscopy and Raman spectroscopy, as well as some electrochemical characterization techniques, including cyclic voltammetry, differential pulse voltammetry and electrochemical impedance spectroscopy were used to characterize the prepared immunosensor. The detection limit of CTnI in plasma samples was calculated as 2.00 fg mL−1, making it an effective tool for acute myocardial infarction testing. © 2021 Elsevier Lt
Design and operation of MinIAQ: An untethered foldable miniature quadruped with individually actuated legs
This paper presents the design, development, and basic operation of MinIAQ, an origami-inspired, foldable, untethered, miniature quadruped robot. Instead of employing multilayer composite structures similar to most microrobotic fabrication techniques, MinIAQ is fabricated from a single sheet of thin A4-sized PET film. Its legs are designed based on a simple four-bar locomotion mechanism that is embedded within its planar design. Each leg is actuated and controlled individually by separate DC motors enabling gait modification and higher degree of freedom on controlling the motion. The origami-inspired fabrication technique is a fast and inexpensive method to make complex 3D robotic structures through successive-folding of laser-machined sheets. However, there is still a need for improvement in modulating and extending the design standards of origami robots. In an effort to addressing this need, the primitive foldable design patterns of MinIAQ for higher structural integrity and rigidity are presented in detail. The current robot takes less than two hours to be cut and assembled and weighs about 23 grams where 3.5 grams is the weight of its body, 7.5 grams is its motors and encoders, 5 grams is its battery, and about 7 grams is its current on-board electronics and sensors. The robot is capable of running about 30 minutes on a single fully charged 150mAh single cell LiPo battery. Using the feedback signals from the custom encoders, MinIAQ can perform a trot gait with a speed of approximately 0.65 Bodylengths/sec, or equivalently 7.5 cm/s. © 2017 IEEE
Effects of Cu diffusion-doping on structural, optical and magnetic properties of ZnO nanorod arrays grown by VPT
Well-aligned ZnO nanorods were prepared by the vapor phase transport method on Si covered with a ZnO buffer layer. After the nanostructure growth, Cu was doped into the ZnO nanorods by diffusion at three different temperatures and for different times. Undoped and Cu diffusion-doped ZnO samples are highly textured, with the c axis of the wurtzite structure along the growth direction. The incorporation of Cu caused some slight changes in the nanorod alignment, although the wurtzite crystal structure was maintained. X-ray photoelectron spectroscopy measurements revealed that Cu ions were in a divalent state and substituted for the Zn2+ ions of the ZnO matrix. Photoluminescence results at 10 K indicate that the incorporation of copper leads to a relative increase of Cu-related structured green band deep level intensity. Magnetic measurements revealed that both undoped and Cu diffusion-doped ZnO samples exhibited room temperature ferromagnetism. It was also found that bound magnetic polarons play an important role in the appearance of room temperature ferromagnetism in Cu diffusion-doped ZnO nanorods
Nutrient composition of five varieties of commonly consumed Nigerian groundnut (<i>Arachis hypogaea</i> L.)
The nutrient composition of the five major varieties of groundnut (<i>Arachis hypogaea</i> L.) commonly consumed in the south-western part of Nigeria was investigated. Raw dryshelled samples were analyzed for proximate (moisture, ash, protein, fat, fiber and carbohydrate), ‘vitamins’ (β-carotene, thiamine, niacin and tocopherol) and minerals (Na, K, Ca, P, Mg, Fe, Mn, Zn, Cu, Se, Co, Al, As, Cd and Pb). Results showed that the groundnuts had 4.12-9.26% moisture, 2.77-3.31% ash, 24.26-26.35% protein, 45.41-48.14% fat, 2.51-2.94% fiber and 15.90-17.75% carbohydrate. All the varieties analyzed showed β-carotene (63.32-65.35mg/100g), thiamin (0.73-0.98mg/100g), niacin (14.00-16.03mg/100g) and tocopherol (18.62-21.07mg/100g) activities; with boro red having significantly (P < 0.05) higher values in all but β-carotene. Heavy metals like Co, As, Cd and Pb were not detected in any of the samples and the other minerals vary with K> P> Mg> Ca> Mn> Cu> Na> Zn> Fe> Al> Se in most of the varieties. Boro red also had the highest elemental contents in most of the minerals analyzed. Thus, these groundnuts can be considered useful foodstuffs in minimizing proteinenergy malnutrition (PEM) and micronutrient deficiencies in Nigeria. However, the boro red variety is most recommended. The outcome of this research is a contribution to the food composition table.<br><br>Se ha investigado la composición en nutrientes de las cinco principales variedades de maní (<i>Arachis hypogaea</i> L.) de consumo habitual en la parte sur-occidental de Nigeria. A las muestras crudas con cáscara y secas se les analizó su composición proximal (humedad, ceniza, proteína, grasa, fibra e hidratos de carbono), vitaminas (β-caroteno, tiamina, niacina y tocoferol) y minerales (Na, K, Ca, P, Mg, Fe, Mn, Zn, Cu, Se, Co, Al, As, Cd y Pb). Los resultados mostraron que el maní tenía entre 4.12 - 9.26% de humedad, 2.77- 3.31% de cenizas, 24.26 - 26.35% de proteína, 45.41 - 48.14% de materia grasa, 2.51 - 2.94% de fibra y 15.90 -17.75% de carbohidratos. Todas las variedades analizadas contenían β-caroteno (63.32-65.35mg/100g), tiamina (0.73-0.98mg/100g), niacina (14.00-16.03mg/100g) y tocoferoles (18.62-21.07mg/100g), siendo la variedad <i>“Boro rojo”</i> la que contiene las cantidades significativamente más altas (P < 0.05), de casi todo. Los metales pesados como, Co, As, Cd y Pb no fueron detectados en ninguna de las muestras y los demás minerales varían en la mayoría de las variedades de la siguiente manera: K> P> Mg> Ca> Mn> Cu> Na> Zn> Fe> Al> Se. La variedad <i>“Boro rojo”</i> también tuvo el mayor contenido elemental en la mayoría de los minerales analizados. Por lo tanto, estos cacahuetes <i>de la variedad “Boro rojo”</i> es la más recomendable y pueden ser considerados unos productos alimenticios útiles para minimizar la malnutrición proteico-energética (MPE) y las deficiencias de micronutrientes en Nigeria. El resultado de esta investigación puede suponer una significativa contribución a la tabla de composición de alimentos
Josephson effect in a microbridge
We report DC Josephson effects observed in a microbridge prepared from an
individual crystalline growth domain of thin film. Josephson effects
were observed by periodic voltage modulations under external magnetic field
with the expected periodicity and by the temperature dependence
of the Josephson critical current . The shape of was
found to be asymmetric, as it is expected for microbridges. The dependence
follows the Ambegaokar-Baratoff relation, which is unexpected for
microbridges. Features in the dynamical resistance curves were attributed to
the periodic motion of Abricosov vortices within the microbridge.Comment: 12 pages, 5 figures, submitted to Physica
Eltrombopag for the treatment of immune thrombocytopenia: The aegean region of Turkey experience
Objective: Immune thrombocytopenia (ITP) is an immune-mediated disease characterized by transient or persistent decrease of the platelet count to less than 100x109/L. Although it is included in a benign disease group, bleeding complications may be mortal. With a better understanding of the pathophysiology of the disease, thrombopoietin receptor agonists, which came into use in recent years, seem to be an effective option in the treatment of resistant cases. This study aimed to retrospectively assess the efficacy, long-term safety, and tolerability of eltrombopag in Turkish patients with chronic ITP in the Aegean region of Turkey. Materials and Methods: Retrospective data of 40 patients with refractory ITP who were treated with eltrombopag in the Aegean region were examined and evaluated. Results: The total rate of response was 87%, and the median duration of response defined as the number of the platelets being over 50x109/L was 19.5 (interquartile range: 5-60) days. In one patient, venous sinus thrombosis was observed with no other additional risk factors due to or related to thrombosis. Another patient with complete response and irregular follow-up for 12 months was lost due to sudden death as the result of probable acute myocardial infarction. Conclusion: Although the responses to eltrombopag were satisfactory, patients need to be monitored closely for overshooting platelet counts as well as thromboembolic events. © 2015 Turkish Society of Hematology. All rights reserved
Two solar eclipses observations in Turkey
In thispap er, the changesin the ionosphere over Turkey due to two solar eclipses are reported. TEC on the eclipse day (26 April 1976) and the intensity of an HF radio wave during itspropagation over 567 km between Ankara and Elazıˇg
on the eclipse day (11 August 1999) exhibited a very marked decrease
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