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The periodic table of urea derivative: small molecules of zinc(II) and nickel(II) of diverse antimicrobial and antiproliferative applications
No full textAssessment of Bisphenol A Levels in Preschool Children: Results of a Human Biomonitoring Study in Ankara, Turkey
No full textObjective: There is general concern regarding environmental chemical
exposure and the impact it may have on human health. This is
particularly important for vulnerable populations such as infants and
children during critical periods of development. Bisphenol A (BPA) is an
endocrine disrupting chemical used worldwide over the last 30 years in
many consumer products. Evidence points to widespread human exposure to
BPA. The aim of this study was to evaluate the exposure of Turkish
preschool children to BPA.
Methods: This study was conducted as a preliminary investigation of BPA
in urine, collected from 3-6 year old children living in Ankara. After
spot urine samples were taken from preschool children, free BPA,
beta-D-glucuronide and total BPA were determined using high-performance
liquid chromatography tandem mass spectrometry and adjusted by
creatinine concentration.
Results: Preschool children from Ankara (n =125; males n = 70, females n
= 55; mean age: 4.50 +/- 1.26) were recruited. BPA was detected in
76.8\% of children from Ankara city, with urinary concentrations ranging
from < limit of quantification to 18.36 mu g/g creatinine. Total BPA
levels were not statistically different between boys (1.26 mu g/g
creatinine) and girls (2.24 mu g/g creatinine) (p >0.05).
Conclusion: This study is an important contribution to the limited
information about childhood exposure to BPA. The estimated daily BPA
intake in this study is substantially lower than the European Food
Safety Authority derived tolerable daily intake of 4 mu g/kg BW/day
Ankara’da Kentlilik Bilincini Oluşturan Değişkenlerin Faktör Analizi İle Değerlendirilmesi
No full textMicrostructural features and mechanical properties of 22MnB5 hot stamping steel in different heat treatment conditions
No full text
INVESTIGATION OF THE INTESTINAL FLORA FROM THE RUMINOCOCCACEAE FAMİLY IN SPORTSMEN AND SEDENTARY MEN
No full textThe Desıgn Of Wave-Cut Endmılls Wıth Varıable Rake Angle Through Helix And Evoluatıon Of Tool Performance
No full textFrezeleme, çok farklı şekilleri oluşturabilme ve yüksek üretim hızlarına ulaşabilme özelliklerinden dolayı en geniş ve yoğun kullanıma sahip talaşlı imalat operasyonlarından biridir. Günümüzde firmalar, işleme süresi ve kalitesini arttırabilmek adına özel kesici kenar tasarımına sahip frezeler kullanmaktadır. Bu çalışmada, helisel parmak frezenin kesici kenarları üzerine özel bir tasarıma sahip bir dalga formu verilerek tasarlanmış takımların standart parmak frezelere göre işleme performansının belirlenmesi ve karşılaştırılması amaçlanmıştır. Dalga formu sayesinde kesici kenar üzerinde -2° ila +10° derece arasında değişken ve kesici kenar boyunca devam eden bir talaş açısı oluşturulmuştur. Çalışmada, malzeme kalite özellikleri ile aynı olan standart ve değişken helis/değişken talaş açılı dalgalı forma sahip iki takımın işleme performansları, TS ISO 8688-2 standardı çerçevesinde, C45 (AISI 1045) çelik ve GG25 dökme demir referans malzemeler kullanılarak kıyaslanmıştır. Deneysel analiz sonuçlarına göre değişken talaş açısı ile kesici kenar mukavemetinin artması, kesme kararlılığının artması ve dolayısı ile takım performansının artması sağlanmıştırMilling is one of the most extensive and intensive machining operations due to its ability to form very different shapes and achieve high production speeds. Nowadays, companies use end mills with special cutting edge design in order to increase processing time and quality. In this study, it is aimed to determine and compare the machining performance of the tools designed by giving a special waveform on cutting edges of helical end mill in accordance with standard end mill. Under favor of to the waveform, rake angle is formed on the cutting edge that varies between -2° and +10°degrees and runs along the cutting edge. In this study, the machining performances of two tools having the same standard and variable helical / variable rake angle waveform which are the same as the material quality characteristics are compared using C45 (AISI 1045) steel and GG25 cast iron reference materials according to TS ISO 8688-2 standard. According to experimental analysis results, increased cutting edge strength with a variable rake angle, the cutting is achieved increased stability and thereby increased tool performanc
