Browsing by Subject "Bovinae"

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    Microcantilever based disposable viscosity sensor for serum and blood plasma measurements
    (2013) Cakmak O.; Elbuken, C.; Ermek, E.; Mostafazadeh, A.; Baris I.; Erdem Alaca, B.; Kavakli I.H.; Urey H.
    This paper proposes a novel method for measuring blood plasma and serum viscosity with a microcantilever-based MEMS sensor. MEMS cantilevers are made of electroplated nickel and actuated remotely with magnetic field using an electro-coil. Real-time monitoring of cantilever resonant frequency is performed remotely using diffraction gratings fabricated at the tip of the dynamic cantilevers. Only few nanometer cantilever deflection is sufficient due to interferometric sensitivity of the readout. The resonant frequency of the cantilever is tracked with a phase lock loop (PLL) control circuit. The viscosities of liquid samples are obtained through the measurement of the cantilever's frequency change with respect to a reference measurement taken within a liquid of known viscosity. We performed measurements with glycerol solutions at different temperatures and validated the repeatability of the system by comparing with a reference commercial viscometer. Experimental results are compared with the theoretical predictions based on Sader's theory and agreed reasonably well. Afterwards viscosities of different Fetal Bovine Serum and Bovine Serum Albumin mixtures are measured both at 23. °C and 37. °C, body temperature. Finally the viscosities of human blood plasma samples taken from healthy donors are measured. The proposed method is capable of measuring viscosities from 0.86. cP to 3.02. cP, which covers human blood plasma viscosity range, with a resolution better than 0.04. cP. The sample volume requirement is less than 150. μl and can be reduced significantly with optimized cartridge design. Both the actuation and sensing are carried out remotely, which allows for disposable sensor cartridges. © 2013 .
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    ItemOpen Access
    Non-intercalative, deoxyribose binding of boric acid to calf thymus DNA
    (Springer, 2014) Ozdemir, A.; Gursacli, R. T.; Tekinay, T.
    The present study characterizes the effects of the boric acid binding on calf thymus DNA (ct-DNA) by spectroscopic and calorimetric methods. UV-Vis absorbance spectroscopy, circular dichroism (CD) spectroscopy, transmission electron microscopy (TEM), isothermal titration calorimetry (ITC), and Fourier transform infrared (FT-IR) spectroscopy were employed to characterize binding properties. Changes in the secondary structure of ct-DNA were determined by CD spectroscopy. Sizes and morphologies of boric acid-DNA complexes were determined by transmission electron microscopy (TEM). The kinetics of boric acid binding to calf thymus DNA (ct-DNA) was investigated by isothermal titration calorimetry (ITC). ITC results revealed that boric acid exhibits a moderate affinity to ct-DNA with a binding constant (K a) of 9.54x104 M -1. FT-IR results revealed that boric acid binds to the deoxyribose sugar of DNA without disrupting the B-conformation at tested concentrations. © 2014 Springer Science+Business Media.
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    Screening and selection of novel animal probiotics isolated from bovine chyme
    (2013) Ozkan, A.D.; Han, D.; Umu O.C.O.; Angun P.; Senturk, B.; Yasa O.; Tekinay, T.
    Probiotics, gut-colonizing microorganisms capable of conferring a number of health benefits to their hosts, are highly desirable as animal feed supplements. Members of the Gram-positive genus Bacillus are often utilized as probiotics, since endospores formed by those bacteria render them highly resistant to environmental extremes and therefore capable of surviving gastrointestinal tract conditions. In this study, 84 distinct bacterial colonies were obtained from bovine chyme and 29 isolates were determined as Bacillus species. These isolates were principally screened for their antimicrobial activity against a group of two Gram-positive and fourGram-negative bacteria, including known human and animal pathogens such as Salmonella enterica, Klebsiella pneumoniae, Pseudomonas aeruginosa, and Staphylococcus aureus. Seven strains displaying strong antimicrobial activity against the test cohort were further evaluated for other properties desirable from animal probiotics, including high spore-forming capacity and adhesiveness, resistance to pH extremes and ability to form biofilms. The isolates were found to resist simulated gastrointestinal conditions and most of the antibiotics tested. In addition, plasmid presence was checked and cytotoxicity tests were performed to evaluate the potential risks of antibiotic resistance transfer and unintended pathogenic effects on host, respectively. We propose that the bacterial isolates are suitable for use as animal probiotics. © Springer-Verlag Berlin Heidelberg and the University of Milan 2012.