This paper suggests an improved method for the sample preparation to quantify vanadium, chromium, nickel and copper in tool steel high-speed by using flame atomic absorption spectrometry. The suggested prepared two specimen solutions containing different internal standard elements: one included quantifications of vanadium or cobalt quantification chromium another phosphoric acid nickel, after w...

Nitric acid plays an important role in the heterogeneous chemistry of the atmosphere. Reactions involving HNO(3) at aqueous interfaces in the stratosphere and troposphere depend on the state of nitric acid at these surfaces. The vapor/liquid interface of HNO(3)-H2O binary solutions and HNO(3)-H(2)SO(4)-H2O ternary solutions are examined here using vibrational sum frequency spectroscopy (VSFS). ...

BACKGROUND Although dietary folate fortification lowers plasma homocysteine and may reduce cardiovascular risk, high-dose folic acid therapy appears to not alter clinical outcome. Folic acid and its principal circulating metabolite, 5-methyltetrahydrofolate, improve vascular function, but mechanisms relating folate dose to vascular function remain unclear. We compared the effects of folic acid ...

Aim This study aimed to compare, through dentin microhardness and colorimetric analysis, the chelating effect of 0.2% chitosan solubilized in different acids. Materials and Methods The second and third cuts of the cervical region of maxillary central incisors were divided into four quadrants, resulting in eight specimens, which were treated with 50 μL of solution for 5 min according to their ...

The nitric acid oxidation of D-glucose was reinvestigated in an effort to better understand and improve the oxidation and subsequent work up steps. The oxidation was carried out using a computer controlled reactor employing a closed reaction flask under an atmosphere of oxygen which allowed for a catalytic oxidation process with oxygen as the terminal oxidant. Removal of nitric acid from produc...

Conventional process of nitrating phenolic compounds involves the use excess corrosive reagents that impose environmental threats. Rapid and environmentally friendly microwave-assisted nitration phenol has been employed to limit nitric acid sulfuric acid. In this study, is reacted calcium nitrate acetic acid, which served as agents. The solution irradiated under microwave complete process. This...

Nitric acid hydrates are important constituents of solid PSC and Cirrus cloud particles. Due to the phase diagram only hexagonal ice and nitric acid trihydrate have a reasonable thermodynamic stability and are commonly observed in the stratosphere. Besides, also a number of metastable modifications might exist: α-NAD, β-NAD, α-NAT, NAP and cubic ice. The existence of these metastable compounds ...

The trial aimed to study the effects of different levels humic acid on antioxidant activity garden thyme. was conducted at experimental fields Agronomy Department, Faculty Agriculture, Urmia University, West Azerbaijan, Iran, and used randomized complete block design with four replications. Three doses; 200 kg ha−1, 400 ha−1 600 control no were treatments. Total phenolic content, total flavonoi...

The tropospheric and stratospheric nitrate aerosol is simulated by a sectional model coupled to the Community Earth System Model. mass fractional contribution aerosols significantly higher in upper troposphere lower stratosphere (UTLS) than that at surface. Both situ measurements simulations show accounts for about 30%–40% of tropopause Asian summer monsoon (ASM) region. Furthermore, condensed ...

Asymmetric dimethylarginine (ADMA) is an endogenous nitric oxide synthase inhibitor that blocks nitric oxide production, while congestive heart failure is associated with increased plasma and tissue ADMA content. Increased plasma ADMA is a strong and independent predictor of all-cause mortality in the community and the strongest predictor of mortality in patients after myocardial infarction. Re...