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    Photodegradation of 2,4-Dichlorophenoxy Acetic Acid on TiO2, ZnO and Fe2O3 by Sunlight
    (Asian Journal Of Chemistry, 2009) Dindar, Bircan; Seven, Ozlem
    The photocatalytic degradation of 2,4-dichlorophenoxy acetic acid (2,4-D) in aqueous solution containing a suspension of titanium dioxide (TiO2), zinc oxide (ZnO) and ferric oxide (Fe2O3) was studied under sunlight or concentrated sunlight. As expected, in the presence of TiO2 and ZnO irradiated by concentrated sunlight, the rate of photodegradation of 2,4-dichlorophenoxy acetic acid was seen to be faster than that irradiated by direct sunlight. Its degradation was not observed in the absence of catalyst and in the dark. TiO2 and ZnO which possess more higher band gap energy than that of Fe2O3 are effective photosensitizer for the degradation of this pesticide under concentrated sunlight. The band gap energy of reddish brown Fe2O3 (2.2 eV) is lower than that of colourless TiO2 (3.2 eV) and ZnO (3.2 eV). Fe2O3 absorbs more longer wavelength of the sunlight than others, but it is not successful as a catalyst under visible light. The results of all UV absorbtion spectroscopy and HPLC analysis regarding products illuminated showed that the complete degradations of 2,4-dichlorophenoxy acetic acid containing ZnO and TiO2 were observed nearly 99 and 85% only in 45 min under concentrated sunlight.
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    Risk Factors for Osteoporosis in Healthy Males
    (De Gruyter Poland Sp Zoo, 2010) Seven, Ozlem; Karapolat, Hale; Eyigor, Sibel; Kirazli, Yesim; Durmaz, Berrin
    We investigated the correlation of bone mineral density (BMD) with risk factors and laboratory parameters (e. g., markers of bone turnover, biochemical indicators, and hormonal factors) in males without secondary osteoporosis. A total of 105 males were divided into two groups: Group 1 (n:52) <60 years, and Group 2 (n: 53) >= 60 years. The subjects were evaluated for risk factors (European Vertebral Osteoporosis Study (EVOS) and BMD) and for biochemical (i.e., blood calcium, blood phosphorus, urinary calcium/phosphorus, creatinine clearance, osteocalcin, and deoxypyridinoline) and hormonal markers (follicle-stimulating hormone [FSH], luteinizing hormone [LH], free testosterone [fT], and parathyroid [PTH]) of bone mineral metabolism. In Group 1, no significant relationship was observed between risk factors for both lumbar and femoral neck BMDs and risk factors and laboratory parameters (p>0.05). On the other hand, we observed in Group 2 a significant positive correlation between lumbar BMD and BMI, BMI at 25 years of age, and fT; in the same group, a negative correlation between lumbar BMD and deoxypyridinoline (p<0.05) was seen. We saw a significant positive correlation between femoral neck BMD and BMI, BMI at 25 years of age, and daily activities of life in Group 2. In addition, we saw a negative correlation between femoral neck BMD and height difference, fT, LH, and deoxypyridinoline in Group 2 (p<0.05). Risk factors for male osteoporosis were multifactorial: demographic and clinical data (difference of height, BMI, physical activity) together with biochemical and hormonal data (deoxypyridinoline, fT, LH) were significant, and most of the risk factors analyzed were related to bone loss in the proximal femur.
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    Synthesis, properties and photodynamic activities of some zinc(II) phthalocyanines against Escherichia coli and Staphylococcus aureus
    (World Sci Publ Co Inc, 2008) Seven, Ozlem; Dindar, Bircan; Aydemir, Sohret; Cilli, Feriha
    Two new zinc phthalocyanine derivatives bearing four 3,5-di-tert-butyl-4-hydroxy-phenyl (ZnPc1) and 3,5-dimethylphenoxy (ZnPc2) have been synthesized and proved by elemental analyses and UV-vis, H-1 NMR, FTIR and MALDI-TOF mass spectra as spectroscopic determination. Thermal stabilities of these neutral Zn-phthalocyanines were performed by thermal gravimetric analysis and, significantly, were found stable up to 373 degrees C for ZnPc1 and 550 degrees C for ZnPc2. In addition, the photostability of the sensitizers was quite successful within 240 min. Furthermore, photodynamic therapy has been investigated using these neutral phthalocyanines. Singlet oxygen generation capacities of ZnPc1 and ZnPc2 were studied using 1,3-diphenyl-iso-benzofuran (50.0 mu M) as a selective singlet oxygen trap in DMSO and both of them demonstrated very high singlet oxygen generation capacity. Photodynamic therapy is of considerable interest for its potential its an antimicrobial therapy on the grounds that the photodynamic activity of these compounds was tested against a Gram-negative bacteria, Escherichia coli and a Gram-positive bacteria, Staphylococcus aureus. Suspensions of the microorganisms were irradiated for 240 min in the presence of ZnPc1 (with hydrophilic group) and ZnPc2 phthalocyanines. In order to simulate solar radiation, we used a 750 W xenon lamp. Minimum photosensitizer concentration was used as 0.1 mg.10 mL(-1) in 1% dimethylsulfoxide/phosphate buffer saline solution (DMSO/PBS). Moreover, the photostability of these compounds has been investigated and the effect of the amount of DMSO tested against selected bacteria. In the dark, with and without Pes, bacterial inactivation did not occur. Bacterial inactivation by light with ZnPc1 was observed in response to Gram-negative bacteria E. coli and Gram-positive bacteria S. aureus, whereas the photoinactivation studies with ZnPc2 have revealed that the lack of its activity is due to its poor affinity for either of the organisms. These results suggest that a neutral amphiphilic photosensitizer may be easily used in an application concerning photoinactivation of bacterial cells as well as ionic photosensitizers. Copyright (c) 2008 Society of Porphyrins & Phthalocyanines.