High-K volcanism in the Afyon region, western Turkey: from Si-oversaturated to Si-undersaturated volcanism

Volcanic rocks of the Afyon province (eastern part of western Anatolia) make up a multistage potassic and ultrapotassic alkaline series dated from 14 to 12 Ma. The early-stage Si-oversaturated volcanic rocks around the Afyon city and further southward are trachyandesitic volcanic activity (14.23 ± 0.09 Ma). Late-stage Si-undersaturated volcanism in the southernmost part of the Afyon volcanic province took place in three episodes inferred from their stratigraphic relationships and ages. Melilite– leucitites (11.50 ± 0.03 Ma), spotted rachyandesites, tephryphonolites and lamproites (11.91 ± 0.13 Ma) formed in the first episode; trachyandesites in the second episode and finally phonotephrites, phonolite, basaltic trachyandesites and nosean-bearing trachyandesites during the last episode. The parameter Q [normative q-(ne + lc + kls + ol)] of western Anatolia volcanism clearly decreased southward with time becoming zero in the time interval 10–15 Ma. The magmatism experienced a sudden change in the extent of Si saturation after 14 Ma, during late-stage volcanic activity of Afyon volcanic province at around 12 Ma, though there was some coexistence of Si-oversaturated and Si-undersaturated magmas during the whole life of Afyon volcanic province

Neogene Uplift and Magmatism of Anatolia: Insights from Drainage Analysis and Basaltic Geochemistry

It is generally agreed that mantle dynamics have played a significant role in generating and maintaining the elevated topography of Anatolia during Neogene times. However, there is much debate about the relative importance of subduction zone and asthenospheric processes. Key issues concern onset and cause of regional uplift, thickness of the lithospheric plate, and the presence or absence of temperature and/or compositional anomalies within the convecting mantle. Here, we tackle these interlinked issues by analyzing and modeling two disparate suites of observations. First, a drainage inventory of 1,844 longitudinal river profiles is assembled. This geomorphic database is inverted to calculate the variation of Neogene regional uplift through time and space by minimizing the misfit between observed and calculated river profiles subject to independent calibration. Our results suggest that regional uplift commenced in the east at 20 Ma and propagated westward. Secondly, we have assembled a database of geochemical analyses of basaltic rocks. Two different approaches have been used to quantitatively model this database with a view to determining the depth and degree of asthenospheric melting across Anatolia. Our results suggest that melting occurs at depths as shallow as 60 km in the presence of mantle potential temperatures as high as 1400°C. There is evidence that potential temperatures are higher in the east, consistent with the pattern of sub-plate shear wave velocity anomalies. Our combined results are consistent with isostatic and admittance analyses and suggest that elevated asthenospheric temperatures beneath thinned Anatolian lithosphere have played a first order role in generating and maintaining regional dynamic topography and basaltic magmatism

Levels of paraoxonase and arylesterase activities and malondialdehyde in workers exposed to ionizing radiation

We examined levels of malondialdehyde (MDA) (an end-product of lipid peroxidation) and paraoxonase (PON1) (an antioxidant enzyme) activity and PON1 phenotypes in people who were exposed to ionizing radiation for different time periods and doses. A total of 78 individuals (mean age 34 7 years) were included in the study. Fifty-one of them were radiology workers whereas the control group was composed of 27 healthy volunteers who had never worked in a radiology-related job. Paraoxon was used as substrate for measurement of PON1 activity levels (basal and NaCl-stimulated). Phenylacetate was used as substrate for measurement of arylesterase activity levels. Cumulative levels of serum NaCl-stimulated PON1/arylesterase activities were utilized for phenotypic differentiation. In radiology workers, three different phenotypes were determined based on paraoxonase/arylesterase ratio. The ratios were 1.09 +/- 0.30 for AA (homozygote low activity); 2.91 +/- 1.07 for AB (heterozygote activity) and 4.97 +/- 1.21 for BB (homozygote high activity). There was a statistically meaningful negative correlation between serum MDA levels and PON1 activity levels in all phenotypes (p 5 years) radiation compared to controls. There was no statistically significant correlation between serum arylesterase activity and MDA levels in these subjects (r = -0.185, p > 0.05). PON1 activity levels were decreased whereas serum MDA levels were increased in individuals exposed to radiation for a long period. PON phenotypes of people employed in jobs which expose them to radiation should be determined and based on these findings they should be advised to avoid risk factors inducing oxidative stress, such as smoking, and to consume foods rich in vitamins and trace elements to increase their antioxidant capacity. Copyright (C) 2003 John Wiley Sons, Ltd.We examined levels of malondialdehyde (MDA) (an end-product of lipid peroxidation) and paraoxonase (PON1) (an antioxidant enzyme) activity and PON1 phenotypes in people who were exposed to ionizing radiation for different time periods and doses. A total of 78 individuals (mean age 34 +/- 7 years) were included in the study. Fifty-one of them were radiology workers whereas the control group was composed of 27 healthy volunteers who had never worked in a radiology-related job. Paraoxon was used as substrate for measurement of PON1 activity levels (basal and NaCl-stimulated). Phenylacetate was used as substrate for measurement of arylesterase activity levels. Cumulative levels of serum NaCl-stimulated PON1/arylesterase activities were utilized for phenotypic differentiation. In radiology workers, three different phenotypes were determined based on paraoxonase/arylesterase ratio. The ratios were 1.09 +/- 0.30 for AA (homozygote low activity); 2.91 +/- 1.07 for AB (heterozygote activity) and 4.97 +/- 1.21 for BB (homozygote high activity). There was a statistically meaningful negative correlation between serum MDA levels and PON1 activity levels in all phenotypes (p &lt; 0.05). PON1 activity levels were found to be 25-35% lower in people who were exposed to long-term ( &gt; 5 years) radiation compared to controls. There was no statistically significant correlation between serum arylesterase activity and MDA levels in these subjects (r = -0.185, p &gt; 0.05). PON1 activity levels were decreased whereas serum MDA levels were increased in individuals exposed to radiation for a long period. PON phenotypes of people employed in jobs which expose them to radiation should be determined and based on these findings they should be advised to avoid risk factors inducing oxidative stress, such as smoking, and to consume foods rich in vitamins and trace elements to increase their antioxidant capacity.</p

LEVELS OF PARAOXONASE AND SERUM LIPID PARAMETERS IN PATIENTS WITH NOISE-INDUCED HEARING LOSS

G&uuml;r&uuml;lt&uuml;ye bağlı işitme kaybı bulunan hastalar ile sağlıklı bireyler arasında y&uuml;ksek dansiteli, d&uuml;ş&uuml;k dansiteli lipoprotein-kolesterol (LDL-K) ve paraoksanaz (PON1) aktivitesi arasındaki ilişkiyi değerlendirmek.G&uuml;r&uuml;lt&uuml;ye bağlı işitme kaybı bulunan 32 hasta &ccedil;alışmaya alındı. Kontrol grubu ise sağlıklı 30 bireyden oluşturuldu. T&uuml;m hasta ve sağlıklı bireylere p&uuml;r ton odiyometri yapıldı. HDL-K, LDL-K ve paraoksanaz seviyelerinin tespiti i&ccedil;in t&uuml;m bireylerden kan &ouml;rnekleri alındı. Bulgular: Sağlıklı bireylerle karşılaştırıldığı zaman g&uuml;r&uuml;lt&uuml;ye bağlı işitme kaybı bulunan hastalarda LDL-K seviyesi anlamlı olarak y&uuml;ksek iken HDL-K seviyeleri ve PON1 aktivitesi anlamlı olarak d&uuml;ş&uuml;k bulunmuştur(p&lt;0.05 ). &Ccedil;alışma grubundaki işitme kaybı 4000 Hz&rsquo;de başlamakta ve 6000 Hz&rsquo;de maksimum seviyeye ulaşmıştır.Mevcut bulgular aterosklerozun kohlear arterde mikroseviyelerde başladığını g&ouml;stermektedir. Bu nedenle kohlear arter perf&uuml;zyonunda azalma sensorin&ouml;ral işitme kaybına neden olmaktadır. D&uuml;ş&uuml;k seviyelerde PON1 aktivitesi ve HDL-K seviyesi ile y&uuml;ksek LDL-K seviyesi g&uuml;r&uuml;lt&uuml;ye bağlı işitme kaybını arttırabilir.To evaluate the relationship between noise induced hearing loss (NIHL) and levels of high density lipoprotein-cholesterol (HDL), low density lipoprotein-cholesterol (LDL-C) and Paraoxonase (PON1) activity in patients with NIHL compared to normal subjects.Thirty two patients with NIHL were recruited in the study. 30 subjects with normal hearing were included in the control group. Pure tone audiometry was applied to all patients and controls. Blood samples were obtained from all subjects to determine levels of HDL-C, LDL-C and PON1.PON1 activity and HDL-C levels were found to be significantly lower while the level of LDL-C was significantly higher in the patients with NIHL compared to healthy controls (p&lt;0.05). In the study group the hearing loss was starting at 4000 Hz and reached to maximum at 6000 Hz.Present findings suggest that atherosclerosis at microlevels begin in cochlear artery. In this respect, decreasing in cochlear arterial perfussion may cause sensorineural hearing loss. Low levels of PON1 activity and HDL-Cand high levels of LDL-C may aggravate the noise induced hearing loss.</p