Browsing by Author "Şahin, A."
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Item 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.Item Open Access Asymmetric effects of central bank funding on commercial banking sector behaviour(Taylor & Francis, 2019-02) Şahin, A.; Berument, HakanIn this paper, we assess the effects of Central Bank Funding (C.B.F.) on commercial bank lending behaviour by using weekly Turkish data from 7 January 2011 to 5 June 2015. To be specific, using the Nonlinear Autoregressive Distributed Lag Error Correction Model, we assess the effects of C.B.F. provided daily by the Central Bank of the Republic of Turkey through Open Market Operations to financial markets. Our empirical evidence reveals that for all types of lending, an increase in C.B.F. (which has a higher cost for commercial banks relative to alternatives) forces commercial banks to borrow from higher-cost channels, i.e., we find that increasing C.B.F. discourages commercial bank lending. We also find that decreases in C.B.F. that proxy what commercial banks can borrow more cheaply from alternative sources increase commercial bank lending. However, increasing C.B.F. is more effective than decreasing C.B.F. for Total Bank Loans, Total Credit Cards and Automobile Loans, and decreasing C.B.F. is more effective in the short run for Consumption Loans, Housing Loans and Commercial Loans: short-run asymmetry. Therefore, we can report only limited support for long-run asymmetry, and consequently, claim that there is magnitude (an increase versus decrease in C.B.F.) and category asymmetry (across different lending categories).Item Open Access Combination of Paclitaxel and R-flurbiprofen loaded PLGA nanoparticles suppresses glioblastoma growth on systemic administration(Elsevier, 2020) Caban-Toktas, S.; Şahin, A.; Lule, S.; Esendagli, G.; Vural, İ.; Karlı-Oğuz, Kader K.; Söylemezoğlu, F.; Mut, M.; Dalkara, T.; Khan, M.; Capan, Y.Malignant gliomas are highly lethal. Delivering chemotherapeutic drugs to the brain in sufficient concentration is the major limitation in their treatment due to the blood-brain barrier (BBB). Drug delivery systems may overcome this limitation and can improve the transportation through the BBB. Paclitaxel is an antimicrotubule agent with effective anticancer activity but limited BBB permeability. R-Flurbiprofen is a nonsteroidal antienflammatory drug and has potential anticancer activity. Accordingly, we designed an approach combining R-flurbiprofen and paclitaxel and positively-charged chitosan-modified poly-lactide-co-glycolic acid (PLGA) nanoparticles (NPs) and to transport them to glioma tissue. NPs were characterized and, cytotoxicity and cellular uptake studies were carried out in vitro. The in vivo efficacy of the combination and formulations were evaluated using a rat RG2 glioma tumor model. Polyethylene glycol (PEG) modified and chitosan-coated PLGA NPs demonstrated efficient cytotoxic activity and were internalized by the tumor cells in RG2 cell culture. In vivo studies showed that the chitosan-coated and PEGylated NPs loaded with paclitaxel and R-flurbiprofen exhibited significantly higher therapeutic activity against glioma. In conclusion, PLGA NPs can efficiently carry their payloads to glioma tissue and the combined use of anticancer and anti-inflammatory drugs may exert additional anti-tumor activity.Item Open Access Nanoengineering InP quantum dot-based photoactive biointerfaces for optical control of neurons(Frontiers Media S.A., 2021-06-23) Karatum, O.; Aria, M. M.; Eren, G. Ö.; Yıldız, E.; Melikov, R.; Srivastava, S. B.; Sürme, S.; Bakış Doğru, I.; Jalali, H. B.; Ulgut, Burak; Şahin, A.; Kavaklı, İ. H.; Nizamoğlu, S.Light-activated biointerfaces provide a non-genetic route for effective control of neural activity. InP quantum dots (QDs) have a high potential for such biomedical applications due to their uniquely tunable electronic properties, photostability, toxic-heavy-metal-free content, heterostructuring, and solution-processing ability. However, the effect of QD nanostructure and biointerface architecture on the photoelectrical cellular interfacing remained unexplored. Here, we unravel the control of the photoelectrical response of InP QD-based biointerfaces via nanoengineering from QD to device-level. At QD level, thin ZnS shell growth (∼0.65 nm) enhances the current level of biointerfaces over an order of magnitude with respect to only InP core QDs. At device-level, band alignment engineering allows for the bidirectional photoelectrochemical current generation, which enables light-induced temporally precise and rapidly reversible action potential generation and hyperpolarization on primary hippocampal neurons. Our findings show that nanoengineering QD-based biointerfaces hold great promise for next-generation neurostimulation devices.Item Open Access Output-employment relationship across sectors: A long-versus short-run perspective(Wiley-Blackwell Publishing, 2015) Şahin, A.; Tansel, A.; Berument, HakanThis paper investigates the nature of the output-employment relationship by using the Turkish quarterly data for the period 1988-2008. Even if we fail to find a long-run relationship between aggregate output and total employment, there are long-run relationships for the aggregate output with non-agricultural employment and sectoral employment levels for seven of nine sectors that we consider. However, a further investigation for the output and employment relationship within a short-run perspective does not reveal statistically significant relationships for either total employment or non-agriculture employment, or eight of the nine sectors that we consider. Although there are various long-run relationships between output and employment, the short-run links between demand and employment are weak. The various implications of this for the economy and the labour market are discussed. As a result, maintaining high levels of output in the long-run creating demand is essential for employment generation. © 2013 Board of Trustees of the Bulletin of Economic Research and John Wiley & Sons Ltd.Item Open Access Output-employment relationship across the employment status: evidence from Turkey(Routledge, 2014) Şahin, A.; Tansel, A.; Berument, HakanThis paper investigates output-employment relationships across different employment statuses and formal versus informal employment divisions for Turkey. Even if we fail to find a long-run relationship between aggregate output and total employment, there are long-run relationships between the aggregate output with all of the formal employment statuses. A further investigation for short-run relationships reveals no statistically significant relationships between aggregate output and total employment and between aggregate output and casual employment but there is a significant short-run relationship between aggregate output and total regular employment. Thus, a sustainable economic growth policy should aim to create formal and regular employment. © 2013 Taylor & Francis.Item Open Access Rethinking interest rate volatility as a macroprudential policy tool(Routledge, 2016) Doğan, B.; Şahin, A.; Berument, HakanAlong with most other central banks, Turkey’s central bank has implemented unconventional policies since the 2007/2008 financial crisis. Financial stability has been one of the targets of these macroprudential policies. However, since Turkey is working toward this goal without increasing its inflation rate, tracking only short-term interest rates to measure this policy’s effectiveness would be inefficient. In this paper, we provide empirical evidence from Turkey that interbank interest rate volatility can be an additional tool for monetary policy makers to help achieve the goal of financial stability. Impulse responses generated from the Vector Autoregressive models indicate that interest rate volatility increases interest rates, depreciates domestic currency and decreases credit growth and output. Its statistically insignificant effect on prices is open to interpretation.