Browsing by Author "Yilmaz, D."

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Open Access
An infant with zoonotic pulmonary tuberculosis due to mycobacterium bovis
(2023-04-12) Üstündaǧ, G.; Şahin, A.; Yazıcı, Yücehan Yılmaz; Aksay, A.; Biçmen, C.; Belkaya, Serkan; Yilmaz, D.
Bovine tuberculosis might be seen in low-income countries, especially in children fed with raw milk. The most common transmission route is fecal-oral way, and it is most likely through unpasteurized dairy products. Although clinical and radiological findings are like non-zoonotic tuberculosis, treatment approaches may differ in individuals with zoonotic tuberculosis. Prevention of zoonotic diseases requires multidisciplinary approaches. These approaches include the development of veterinary and surveillance studies for the detection of communicable diseases in farm animals, as well as informing the public about raw milk consumption. In this case report, a patient with zoonotic pulmonary tuberculosis related to Mycobacterium bovis because of consumption of raw milk was presented. A five-month-old male was admitted to the hospital due to a persistent, feverless, non-productive cough since birth. Empirical antibiotic treatment was started with a preliminary diagnosis of pneumonia because of left upper lobe and right pericardial infiltration on chest X-ray. However, after two weeks of antimicrobial therapy, the patient's clinical and laboratory findings did not improve. This led to the referral for a computed tomography imaging, which revealed tracheomalacia, consolidation on the right upper lobe, an indistinguishable mass or consolidation on the left middle lobe of the lung, peribronchial thickening on the basal segment of the lower lobe, and mediastinal lymphadenopathy. Three consecutive days of fasting gastric lavage fluid was sent to the reference laboratory for acid-resistant bacillus examination, polymerase chain reaction (PCR) and culture studies. As the clinical findings were compatible and PCR was positive, the patient was started on quadruple antituberculous therapy. After initiation of anti-tuberculosis drugs, the patient's findings radiologically and clinically were improved. Mycobacterium bovis was grown in the culture. In the meantime, it was discovered that the patient was fed with raw milk. Due to the patient's clinical symptoms and the growth of Mycobacterium bovis in the gastric lavage fluid culture, the diagnosis of bovine tuberculosis was made. The culprit was that the milk of the cow belonging to the patient's family, which was later found to be infected with M.bovis, was milked and given to the patient without boiling. Today, unpasteurized dairy products continue to be consumed, especially in rural areas. One of the most important steps to prevent zoonotic diseases is to raise awareness about not consuming raw milk and undercooked meat. To elucidate the epidemiological link in childhood, taking a good anamnesis, including questioning raw milk consumption, is essential in the diagnosis of tuberculosis. © 2023 Ankara Microbiology Society. All rights reserved.
Open Access
Asymmetric light propagation in chirped photonic crystal waveguides
(Optical Society of American (OSA), 2012) Kurt H.; Yilmaz, D.; Akosman, A.E.; Özbay, Ekmel
We report numerical and experimental investigations of asymmetric light propagation in a newly designed photonic structure that is formed by creating a chirped photonic crystal (PC) waveguide. The use of a non-symmetric distribution of unit cells of PC ensures the obtaining of asymmetric light propagation. Properly designing the spatial modulation of a PC waveguide inherently modifies the band structure. That in turn induces asymmetry for the light's followed path. The investigation of the transmission characteristics of this structure reveals optical diode like transmission behavior. The amount of power collected at the output of the waveguide centerline is different for the forward and backward propagation directions in the designed configuration. The advantageous properties of the proposed approach are the linear optic concept, compact configuration and compatibility with the integrated photonics. These features are expected to hold great potential for implementing practical optical rectifier-type devices. © 2012 Optical Society of America.
Open Access
Isolated subcutaneous abscess: A rare presentation of extrapulmonary tuberculosis
(Lippincott Williams & Wilkins, 2023-08-01) Sahin, A.; Kara-Aksay, A.; Bicmen, C.; Belkaya, Serkan; Kaya, A.; Yilmaz, D.
Open Access
Looking for timing variations in the transits of 16 exoplanets
(Oxford University Press, 2024-04-05) Yalcinkaya, S.; Esmer, E. M.; Basturk, O.; Muhaymin, A.; Kutluay, A. C.; Silistre, D. I.; Akar, F.; Southworth, J.; Mancini, L.; Davoudi, F.; Karamanli, E.; Tezcan, F.; Demir, E.; Yilmaz, D.; Guleroglu, E.; Tekin, M.; Taskin, I.; Aladag, Y.; Sertkan, E.; Kurt, U. Y.; Fisek, S.; Kaptan, S.; Alis, S.; Aksaker, N.; Yelkenci, F. K.; Tezcan, C. T.; Kaya, A.; Oglakkaya, D.; Aydin, Z. S.; Yesilyaprak, C.
We update the ephemerides of 16 transiting exoplanets using our ground-based observations, new Transiting Exoplanet Survey Satellite data, and previously published observations including those of amateur astronomers. All these light curves were modelled by making use of a set of quantitative criteria with the exofast code to obtain mid-transit times. We searched for statistically significant secular and/or periodic trends in the mid-transit times. We found that the timing data are well modelled by a linear ephemeris for all systems except for XO-2 b, for which we detect an orbital decay with the rate of -12.95 +/- 1.85 ms yr(-1) that can be confirmed with future observations. We also detect a hint of potential periodic variations in the transit timing variation data of HAT-P-13 b, which also requires confirmation with further precise observations.
Open Access
Theoretical and experimental investigations of asymmetric light transport in graded index photonic crystal waveguides
(AIP Publishing, 2014) Giden, I. H.; Yilmaz, D.; Turduev, M.; Kurt, H.; Colak, E.; Özbay, Ekmel
To provide asymmetric propagation of light, we propose a graded index photonic crystal (GRIN PC) based waveguide configuration that is formed by introducing line and point defects as well as intentional perturbations inside the structure. The designed system utilizes isotropic materials and is purely reciprocal, linear, and time-independent, since neither magneto-optical materials are used nor time-reversal symmetry is broken. The numerical results show that the proposed scheme based on the spatial-inversion symmetry breaking has different forward (with a peak value of 49.8%) and backward transmissions (4.11% at most) as well as relatively small round-trip transmission (at most 7.11%) in a large operational bandwidth of 52.6 nm. The signal contrast ratio of the designed configuration is above 0.80 in the telecom wavelengths of 1523.5-1576.1 nm. An experimental measurement is also conducted in the microwave regime: A strong asymmetric propagation characteristic is observed within the frequency interval of 12.8 GHz-13.3 GHz. The numerical and experimental results confirm the asymmetric transmission behavior of the proposed GRIN PC waveguide. (C) 2014 AIP Publishing LLC.