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141.
A Bifunctional Photosensitizer for Enhanced Fractional Photodynamic Therapy: Singlet Oxygen Generation in the Presence and Absence of Light
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Dr. Ilke Simsek Turan Deniz Yildiz Abdurrahman Turksoy Dr. Gurcan Gunaydin Prof. Dr. Engin U. Akkaya 《Angewandte Chemie (International ed. in English)》2016,55(8):2875-2878
The photosensitized generation of singlet oxygen within tumor tissues during photodynamic therapy (PDT) is self‐limiting, as the already low oxygen concentrations within tumors is further diminished during the process. In certain applications, to minimize photoinduced hypoxia the light is introduced intermittently (fractional PDT) to allow time for the replenishment of cellular oxygen. This condition extends the time required for effective therapy. Herein, we demonstrated that a photosensitizer with an additional 2‐pyridone module for trapping singlet oxygen would be useful in fractional PDT. Thus, in the light cycle, the endoperoxide of 2‐pyridone is generated along with singlet oxygen. In the dark cycle, the endoperoxide undergoes thermal cycloreversion to produce singlet oxygen, regenerating the 2‐pyridone module. As a result, the photodynamic process can continue in the dark as well as in the light cycles. Cell‐culture studies validated this working principle in vitro. 相似文献
142.
The paper presents the application of an advanced second moment closure (SMC) to the prediction of the flow field within stationary
and rotating square cross-sectioned ducts. The rotation number is 0.1 and the Reynolds number is 100,000. The SMC used satisfies
the two-component-limit and has been reported in literature to produce improvements in the prediction of a wide range of flows.
The computations were initially validated against existing experimental data, then used to obtain the various budget terms
for the Reynolds stresses. The aims of this work are to judge the performance of the advanced SMC and to gain insight into
the physics of rotation and its interaction with secondary flows based on the predicted Reynolds stress budgets for high Reynolds
number flows. It was found that the advanced SMC performs slightly better than a basic SMC, although neither model predicts
the flow on the suction side of the rotating duct well. On the pressure side computed budgets are similar to those obtained
in a significantly higher aspect ratio duct. On the suction side, however, the effects of the secondary flows are clearly
seen through a significant decrease of various budget terms, a feature not seen in a higher aspect ratio duct, and it thus
appears that the models do not entirely capture the interaction between the stabilizing rotation and secondary flow effects. 相似文献
143.
Dönüs Tuncel Müge Artar Saltuk Bugra Hanay 《Journal of polymer science. Part A, Polymer chemistry》2010,48(21):4894-4899
The effects of cucurbit[n]uril on the dissolution and the photophysical properties of nonionic conjugated polymers in water are described. For this purpose, a fluorine‐based polymer, namely, poly[9,9‐bis{6(N,N‐dimethylamino)hexyl}fluorene‐co‐2,5‐thienylene (PFT) was synthesized and characterized by spectroscopic techniques including 1D and 2D NMR, UV–vis, fluorescent spectroscopy, and matrix‐assisted laser desorption mass spectrometry (MALDI‐MS). For the first time, it was demonstrated that a nonionic conjugated polymer can be made soluble in water through an inclusion complex formation with CB8. The structure of the complex was elucidated by NMR experiments including 1H and selective 1D‐NOESY. This complex emits green and is highly fluorescent with fluorescent quantum yield of 35%. In contrast, CB6 or water‐soluble CB7 although they are chemically identical to CB8 do not have any effect on the dissolution and photophysical properties of PFT. By preparing a protonated version of PFT, the optical properties of PFT in methanol, protonated PFT and PFT@CB8 in water have been studied and compared. It was also observed that the morphology of the polymer PFT was affected by the presence of CB8. Thus CB8‐assisted self‐assembly of polymer chains leads to vesicles formation; these structures were characterized by DLS, AFM, SEM, and TEM fluorescent optical microscopy. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010 相似文献
144.
O. Karabulut M. Parlak K. Yilmaz R. Turan B. G. Akinoglu 《Crystal Research and Technology》2003,38(12):1071-1076
GaSe single crystals grown by Bridgman method have been doped by ion implantation technique. The samples were bombarded in the direction parallel to c‐axis by Si ion beam of about 100 keV to doses of 1 × 1016 ions/cm2 at room temperature. The effects of Si implantation with annealing at 500 and 600 °C on the electrical properties have been studied by measuring the temperature dependent conductivity and photoconductivity under different illumination intensities in the temperature range of 100–320 K. It is observed that Si implantation increases the room temperature conductivity 10−7 to 10−3 (Ω‐cm)−1 depending on the post annealing temperature. The analysis of temperature dependent conductivity shows that at high temperature region above 200 K, the transport mechanism is dominated by thermal excitation in the doped and undoped GaSe samples. At lower temperatures, the conduction of carriers is dominated by variable range hopping mechanism in the implanted samples. Annealing of the samples at and above 600 °C weakens the temperature dependence of the conductivity and photoconductivity. This indicates that annealing of the implanted samples activates Si‐atoms and increases structural deformations and stacking faults. The same behavior was observed from photoconductivity measurements. Hence, photocurrent‐illumination intensity dependence in the implanted samples obeys the power low Ipc ∝ Φn with n between 1 and 2 which is an indication of continuous distribution of localized states in the band gap. (© 2003 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
145.
The problem of active shielding of some domain from the effect of the field generated in another domain is considered. The active shielding is implemented via the placement of additional sources in such a way that the total contribution of all sources leads to the desirable effect. The obtained solution does not require either the knowledge of the particular Green's function or any other information on source distribution and the surrounding medium. It is also important that along with undesirable field to be shielded, a desirable field can be admitted in the analysis. The solution of the problem requires only knowledge of the total field on the perimeter of the shielded domain. The active shielding sources are obtained for both the linear and nonlinear formulations of the problem. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
146.
Turan Ozturk Author Vitae Erdal Ertas Author Vitae Author Vitae 《Tetrahedron》2005,61(47):11055-11077
147.
Diabetes mellitus is characterized by hyperglycemia, a relative lack of insulin. The metabolic disturbances in diabetic patients are often associated with cardiac and liver dysfunctions. Generally, experimental diabetic models in animals have been used to study diabetes-related changes in organ function, but the complexity of intact tissues can cause contradictory results. For this reason, different techniques have been used to understand the mechanisms of these dysfunctions in diabetic organs. The purpose of the present study is to investigate the effects of streptozotocin (STZ)-induced diabetes on rat liver and heart tissues at the molecular level by Fourier Transform Infrared (FTIR) spectroscopy. Wistar rats of both sexes, weighing 200-250 g, were made diabetic by a single injection of 50 mg kg(-1) intraperitoneal (i.p.) streptozotocin dissolved in 0.05 M citrate buffer (pH 4.5) and they were kept for 4-5 weeks. The diabetes status was checked by measuring the blood glucose level. In the complex FTIR spectra, the bands in the CH region for example the CH(2) antisymmetric and symmetric stretching, the CH(3) symmetric and asymmetric stretching vibrations due to lipids and proteins in the 3000-2800 cm(-1) region and CH(2) scissoring around 1464 cm(-1) and the CH(3) scissoring at 1454 cm(-1) were analyzed. Characteristic spectral bands of these diabetic samples were compared with those of control group to confirm the effect of diabetes on liver and heart tissues. The FTIR spectra revealed dramatic differences in the band positions and bandwidths, signal intensity values and signal intensity ratios between diabetic and control tissues. Similar differences were observed for diabetic liver and heart tissues. A significant increase in the bandwidth of the CH(2) symmetric and antisymmetric stretching and the CH(3) symmetric and asymmetric stretching bands has been observed for both tissue types. The wavenumber of the CH(3) asymmetric stretching band shifts to lower values, indicating an increase in the order in the deep interior part of the lipid chains. The ratio of the CH(2) symmetric to CH(3) symmetric stretching band (lipid/protein ratio) decreases by 13% for diabetic heart and liver tissues. A decrease is also detected in the ratio of the CH(2) scissoring to the CH(3) scissoring mode. The overall intensity of these bands is seen to increase for diabetic tissues. 相似文献
148.
This paper proposes a conditional technique for the estimation of VaR and expected shortfall measures based on the skewed
generalized t (SGT) distribution. The estimation of the conditional mean and conditional variance of returns is based on ten popular variations
of the GARCH model. The results indicate that the TS-GARCH and EGARCH models have the best overall performance. The remaining
GARCH specifications, except in a few cases, produce acceptable results. An unconditional SGT-VaR performs well on an in-sample
evaluation and fails the tests on an out-of-sample evaluation. The latter indicates the need to incorporate time-varying mean
and volatility estimates in the computation of VaR and expected shortfall measures. 相似文献
149.
May Korachi Zi?an Turan Kenan ?entürk Fikrettin ?ahin Necdet Aslan 《Journal of Electrostatics》2009,67(4):678-685
A newly developed, low cost plasma system that works at atmospheric pressure and operates with both DC or AC high voltage power supplies was presented. This system was tested for its biocidal effect on a wide range of micro-organisms in water. Optimal killing parameters such as time, temperature and AC and DC high voltage power levels were tested for bacteria (Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, Streptococcus mutans, Bacillus subtilis), yeast (Candida albicans), fungi (Aspergillus niger) and green algae. Results show this system to have a very efficient biocidal effect on most bacteria, algae and fungi in water. 相似文献
150.
C. Turan P. M. Carrica L. Weber 《International Journal of Computational Fluid Dynamics》2013,27(3-4):137-153
Strong flow entrainment has been observed downstream of spillways constructed with flow deflectors. This water entrainment has important environmental and ecological impacts because it improves the mixing of powerhouse and spillway flows, but may negatively impact fish migration or create adverse flow conditions. Most studies found in the literature attempt to explain this entrainment with turbulent mixing. Both reduced-scale hydraulic models and single-phase, isotropic RANS models grossly under-predict the degree of entrainment observed in prototypes. In this paper, an anisotropic model that accounts for the bubble volume fraction and attenuation of the normal velocity fluctuations at the free surface is presented. The model adequately predicts the main mechanisms causing water entrainment and compares well against experimental data for a round surface jet and for Brownlee Dam at model scale. It is shown that appropriate entrainment can only be captured if the turbulence anisotropy and the two-phase nature of the flow are modelled. 相似文献