PubMed İndeksli Yayınlar Koleksiyonu / PubMed Indexed Publications Collection
Permanent URI for this collectionhttps://hdl.handle.net/11147/7645
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Article Citation - WoS: 13Citation - Scopus: 13Her2-Targeted, Degradable Core Cross-Linked Micelles for Specific and Dual Ph-Sensitive Dox Release(John Wiley and Sons Inc., 2021) Bayram, Nazende Nur; Ulu, Gizem Tuğçe; Topuzoğulları, Murat; Baran, Yusuf; Dinçer İşoğlu, SevilHere, a targeted, dual-pH responsive, and stable micelle nanocarrier is designed, which specifically selects an HER2 receptor on breast cancer cells. Intracellularly degradable and stabilized micelles are prepared by core cross-linking via reversible addition-fragmentation chain-transfer (RAFT) polymerization with an acid-sensitive cross-linker followed by the conjugation of maleimide-doxorubicin to the pyridyl disulfide-modified micelles. Multifunctional nanocarriers are obtained by coupling HER2-specific peptide. Formation of micelles, addition of peptide and doxorubicin (DOX) are confirmed structurally by spectroscopical techniques. Size and morphological characterization are performed by Zetasizer and transmission electron microscope (TEM). For the physicochemical verification of the synergistic acid-triggered degradation induced by acetal and hydrazone bond degradation, Infrared spectroscopy and particle size measurements are used. Drug release studies show that DOX release is accelerated at acidic pH. DOX-conjugated HER2-specific peptide-carrying nanocarriers significantly enhance cytotoxicity toward SKBR-3 cells. More importantly, no selectivity toward MCF-10A cells is observed compared to HER2(+) SKBR-3 cells. Formulations cause apoptosis depending on Bax and Caspase-3 and cell cycle arrest in G2 phase. This study shows a novel system for HER2-targeted therapy of breast cancer with a multifunctional nanocarrier, which has higher stability, dual pH-sensitivity, selectivity, and it can be an efficient way of targeted anticancer drug delivery.Article Citation - WoS: 8Citation - Scopus: 10Use of Magic Sandwich Echo and Fast Field Cycling Nmr Relaxometry on Honey Adulteration With Corn Syrup(John Wiley and Sons Inc., 2021) Berk, Berkay; Çavdaroğlu, Çağrı; Grunin, Leonid; Ardelean, Ioan; Kruk, Danuta; Mazı, Bekir G.; Öztop, Halil Mecitconventional time domain nuclear magnetic resonance (TD-NMR) pulse sequence: magic sandwich echo (MSE) was used to detect the adulteration of honey by glucose syrup (GS) and high fructose corn syrup (HFCS) accompanied with T-1 and T-2 relaxation times. Also, fast field cycling NMR (FFC-NMR) relaxometry and multivariate analysis were performed to investigate the adulteration. RESULTS Higher maltose in GS and changing glucose to water ratio of HFCS gave high correlation with the crystal content values. In HFCS adulteration, two separate populations of protons having different T-2 values were detected and T-1 times were also used to determine GS adulteration. Addition of GS increased T-1 while addition of HFCS increased T-2, significantly. CONCLUSION The results showed that it is possible to differentiate the unadulterated and adulterated honey samples by using TD-NMR relaxation times and crystal content values obtained by the MSE sequence. By FFC-NMR relaxometry, not only GS addition but also the amount of GS was examined. The multivariate analysis technique of principal component analysis was able to distinguish the types of adulterants.Article Citation - WoS: 2Citation - Scopus: 3Nonvisual Aspects of Spatial Knowledge: Wayfinding Behavior of Blind Persons in Lisbon(John Wiley and Sons Inc., 2020) Kan-Kılıç, Didem; Doğan, Fehmi; Duarte, EmiliaBlind individuals' wayfinding performance in complex urban environments is a complex phenomenon. This study investigates the wayfinding strategies of congenitally blind individuals in an urban context. The aim of the study was to assess the extent to which the environmental auditory cues are of primary importance for their wayfinding strategies. The study was conducted in Lisbon, Portugal. Results suggest that auditory information was the most used environmental cue and that a feeling of enclosure is the most important environmental feature during wayfinding. These results corroborate previous findings suggesting that increased familiarity with the environment results in more efficient wayfinding strategies, and that lack of environmental auditory cues could be compensated by a robust cognitive map. The study highlights multidimensional sensory experiences of urban environments and nonvisual aspects of spatial perception.Article Citation - WoS: 6Citation - Scopus: 8Outer-Membrane Protease (ompt) Based E.coli Sensing With Anionic Polythiophene and Unlabeled Peptide Substrate(John Wiley and Sons Inc., 2020) Sinsinbar, Gaurav; Gudlur, Sushanth; Wood, Sarah E.; Ammanath, Gopal; Yıldız, Ümit Hakan; Alagappan, Palaniappan; Liedberg, BoE. coli and Salmonella are two of the most common bacterial pathogens involved in foodborne and waterborne related deaths. Hence, it is critical to develop rapid and sensitive detection strategies for near-outbreak applications. Reported is a simple and specific assay to detect as low as 1 CFU mL(-1)of E. coli in water within 6 hours by targeting the bacteria's surface protease activity. The assay relies on polythiophene acetic acid (PTAA) as an optical reporter and a short unlabeled peptide (LL37(FRRV)) previously optimized as a substrate for OmpT, an outer-membrane protease on E. coli. LL37(FRRV)interacts with PTAA to enhance its fluorescence while also inducing the formation of a helical PTAA-LL37(FRRV)construct, as confirmed by circular dichroism. However, in the presence of E. coli LL37(FRRV)is cleaved and can no longer affect the conformations and optical properties of PTAA. This ability to distinguish between an intact and cleaved peptide was investigated in detail using LL37(FRRV)sequence variants.Article Citation - WoS: 28Citation - Scopus: 33Rapid Detection of Green-Pea Adulteration in Pistachio Nuts Using Raman Spectroscopy and Chemometrics(John Wiley and Sons Inc., 2021) Taylan, Osman; Çebi, Nur; Yılmaz, Mustafa Tahsin; Sağdıç, Osman; Özdemir, Durmuş; Balubaid, MohammedBACKGROUND Ground pistachio nut is prone to adulteration because of its high economic value and wide usage. Green pea is known as the main adulterant in frauds involving pistachio nuts. The present study developed a new, rapid, reliable and low-cost methodology by using a portable Raman spectrometer in combination with chemometrics for the detection of green pea in pistachio nuts. RESULTS Three different methods of Raman spectroscopy-based chemometrics analysis were developed for the determination of green-pea adulteration in pistachio nuts. The first method involved the development of hierarchical cluster analysis (HCA) and principal component analysis (PCA), which differentiated authentic pistachio nuts from green pea and green pea-adulterated samples. The best classification pattern was observed in the adulteration range of 20-80% (w/w). In addition to classification methods, partial least squares regression (PLSR) and genetic algorithm-based inverse least squares (GILS) were also used to develop multivariate calibration models to determine quantitatively the degree of green-pea adulteration in grounded pistachio nuts. The spectral range of 1790-283 cm(-1)was used in the case of multivariate data analysis. A green-pea adulteration level of 5-80% (w/w) was successfully identified by PLSR and GILS. The correlation coefficient of determination (R-2) was determined as 0.91 and 0.94 for the PLSR and GILS analyses, respectively. CONCLUSION A Raman spectrometer combined with chemometrics has a high capability with regard to the detection of adulteration in pistachio nuts, combined with low cost, strong reliability, a high level of accuracy, rapidity of analysis, and minimum sample preparation.Article Citation - WoS: 22Citation - Scopus: 24Scaffold-Free Biofabrication of Adipocyte Structures With Magnetic Levitation(John Wiley and Sons Inc., 2021) Sarıgil, Öykü; Yalçın Özuysal, Özden; Anıl İnevi, Müge; Meşe Özçivici, Gülistan; Fıratlıgil Yıldırır, Burcu; Fıratlıgil Yıldırır, Burcu; Ünal, Yağmur Ceren; Ünal, Yağmur Ceren; Yalçın Özuysal, Özden; Özçivici, Engin; Meşe, Gülistan; Sarıgil, Öykü; Özçivici, Engin; Anıl İnevi, Müge; Meşe Özçivici, GülistanTissue engineering research aims to repair the form and/or function of impaired tissues. Tissue engineering studies mostly rely on scaffold-based techniques. However, these techniques have certain challenges, such as the selection of proper scaffold material, including mechanical properties, sterilization, and fabrication processes. As an alternative, we propose a novel scaffold-free adipose tissue biofabrication technique based on magnetic levitation. In this study, a label-free magnetic levitation technique was used to form three-dimensional (3D) scaffold-free adipocyte structures with various fabrication strategies in a microcapillary-based setup. Adipogenic-differentiated 7F2 cells and growth D1 ORL UVA stem cells were used as model cells. The morphological properties of the 3D structures of single and cocultured cells were analyzed. The developed procedure leads to the formation of different patterns of single and cocultured adipocytes without a scaffold. Our results indicated that adipocytes formed loose structures while growth cells were tightly packed during 3D culture in the magnetic levitation platform. This system has potential for ex vivo modeling of adipose tissue for drug testing and transplantation applications for cell therapy in soft tissue damage. Also, it will be possible to extend this technique to other cell and tissue types.Article Citation - WoS: 69Citation - Scopus: 77Novel Zein-Based Multilayer Wound Dressing Membranes With Controlled Release of Gentamicin(John Wiley and Sons Inc., 2019) Kimna, Ceren; Tamburacı, Sedef; Tıhmınlıoğlu, FundaRecently, functional multilayer scaffolds with controlled drug release ability come into prominence for wound healing applications to mimic the layered structure of skin tissue and prevent the possible infections at the defect site. In this study, controlled antibiotic releasing zein bilayer membranes were fabricated for treatment of acute skin infections. Gentamicin loaded fibers were prepared by electrospinning on the membrane surface. Membranes were characterized with scanning electron microscope, atomic force microscopy, Fourier transform infrared spectroscopy, contact angle, mechanical analysis, swelling, degradation, and water vapor permeability studies. In vitro cytotoxicity, cell attachment, and proliferation were investigated. Cell attachment on fiber layer was observed with fluorescence imaging. Fabricated fibers showed structural similarity to the skin tissue layers with a fiber diameter range of 350-425 nm and film thickness in the range of 311-361 mu m. Mechanical properties were found compatible with the skin tissue. In addition, membranes showed antimicrobial activity against Staphylococcus aureus and Escherichia coli. The sustained release was achieved with a cumulative release of 94%. Membranes did not show any cytotoxic effect. NIH/3T3 and HS2 cell lines were proliferated on each layer mimicking the multilayer skin tissue. Hence, zein-based bilayer membrane showed promising properties to be used as a potential antimicrobial wound dressing for skin tissue regeneration. (c) 2018 Wiley Periodicals, Inc.Article Citation - WoS: 15Citation - Scopus: 17Improved Activity of Alpha-L From Geobacillus Vulcani Gs90 by Directed Evolution: Investigation on Thermal and Alkaline Stability(John Wiley and Sons Inc., 2019) Sürmeli, Yusuf; İlgü, Hüseyin; Şanlı Mohamed, Gülşahalpha-L-Arabinofuranosidase (Abf) is a potential enzyme because of its synergistic effect with other hemicellulases in agro-industrial field. In this study, directed evolution was applied to Abf from Geobacillus vulcani GS90 (GvAbf) using one round error-prone PCR and constructed a library of 73 enzyme variants of GvAbf. The activity screening of the enzyme variants was performed on soluble protein extracts using p-nitrophenyl alpha-L-arabinofuranoside as substrate. Two high activity displaying variants (GvAbf L307S and GvAbf Q90H/L307S) were selected, purified, partially characterized, and structurally analyzed. The specific activities of both variants were almost 2.5-fold more than that of GvAbf. Both GvAbf variants also exhibited higher thermal stability but lower alkaline stability in reference to GvAbf. The structural analysis of GvAbf model indicated that two mutation sites Q90H and L307S in both GvAbf variants are located in TIM barrel domain, responsible for catalytic action in many Glycoside Hydrolase Families including GH51. The structure of GvAbf model displayed that the position of L307S mutation is closer to the catalytic residues of GvAbf compared with Q90H mutation and also L307S mutation is conserved in both variants of GvAbf. Therefore, it was hypothesized that L307S amino acid substitution may play a critical role in catalytic activity of GvAbf. (C) 2018 International Union of Biochemistry and Molecular Biology, Inc.Article Citation - WoS: 16Citation - Scopus: 16Secular Trends in Opportunistic Infections, Cancers and Mortality in Patients With Aids During the Era of Modern Combination Antiretroviral Therapy(John Wiley and Sons Inc., 2018) Sezgin, Efe; Van Natta, Mark L.; Thorne, Jennifer E.; Puhan, M. A.; Jabs, D. A.Objectives: The aim of the study was to estimate the incidence of, determine risk factors for, and investigate the consequences of opportunistic infections (OIs) and malignancies among patients with the acquired immune deficiency syndrome (AIDS) in the era of modern combination antiretroviral therapy (cART). Methods: Three enrolment periods (1998–2002, 2003–2005 and 2006–2012), corresponding to changes in predominant cART regimens, were compared among 1889 participants enrolled in a prospective cohort study, the Longitudinal Study of Ocular Complications of AIDS (LSOCA). Incidences of AIDS-related OIs and cancers were estimated. Multivariate logistic and Cox regression models were used to determine the effect of demographic and clinical characteristics on OIs and mortality. Results: Between participants enrolled in the 1998–2002 and 2006–2012 enrolment periods, the incidence of OIs decreased from 27 per 1000 person-years (PY) to 11 per 1000 PY (P < 0.001), and mortality decreased from 41 per 1000 PY to 18 per 1000 PY (P < 0.0001), corresponding to improvements in cART regimens. Conclusions: Improvements in cART regimens led to a progressive decline in the incidence of OIs and mortality between 1999 and 2013 among patients with AIDS in the era of modern cART.Article Citation - WoS: 59Citation - Scopus: 57Cmos Enabled Microfluidic Systems for Healthcare Based Applications(John Wiley and Sons Inc., 2018) Hussian, Muhammad M.; Khan, Sherjeel M.; Gümüş, Abdurrahman; Nassar, Joanna M.With the increased global population, it is more important than ever to expand accessibility to affordable personalized healthcare. In this context, a seamless integration of microfluidic technology for bioanalysis and drug delivery and complementary metal oxide semiconductor (CMOS) technology enabled data-management circuitry is critical. Therefore, here, the fundamentals, integration aspects, and applications of CMOS-enabled microfluidic systems for affordable personalized healthcare systems are presented. Critical components, like sensors, actuators, and their fabrication and packaging, are discussed and reviewed in detail. With the emergence of the Internet-of-Things and the upcoming Internet-of-Everything for a people–process–data–device connected world, now is the time to take CMOS-enabled microfluidics technology to as many people as possible. There is enormous potential for microfluidic technologies in affordable healthcare for everyone, and CMOS technology will play a major role in making that happen.