Is nonnegative matrix factorization (NMF) truly a blind source separation method?

I have been recently interested in source separation for musical signals. The paper I study (see below), uses nonnegative matrix factorization (NMF) for separation of musical audio recordings...

11 May 2015 8,961 3 View

Why do the absorbance values of different concentrations of ascorbic acid solutions mixed with DPPH free radicals stay constant?

26 January 2021 458 14 View

IC50 value from this graph?

01 January 2021 6,848 4 View

Is the fluorescent protein must be totally photobleached in FRAP assay?

Hi I have tried to measure the mobility of a protein of interest by the FRAP assay. The protein was fused with GFP. I overexpressed the fusion protein in Hela cells. However, when the area of the...

14 December 2020 6,567 1 View

Is rotary evaporator a must before going through TPC, TFC and DPPH assay?

I am doing an optimization of ginger extract using doe software, firstly I extract the ground ginger with 20ml solvents of 60%, 70% and 80% ethanol using the ultrasound water bath in different...

23 October 2020 3,268 10 View

How to calculate IC50 of plant extracts dissolved in DMSO?

Greeting! Currently I am working with my plant extracts with different concentration on DPPH assay and anti-tyrosinase assay. All of my plant extracts with different concentration are dissolved...

02 October 2020 3,185 3 View

Why is it necessary to vortex and incubate in dark the sample and DPPH solution and other DPPH questions?

Hi all, In the determination of Antioxidant capacity of fruit samples, I used DPPH assay and have a few questions regarding the DPPH assay 1) why is it necessary to vortex and incubate in dark...

30 August 2020 246 3 View

How do I perform the correlation between phenolic contents of extractives with hydroxyl radical scavenging activity?

I want to show the correlation between total phenol and flavonoid contents of extractives with DPPH, hydroxyl, and ferric reducing scavenging activity. I would prefer to use GraphPad prism. Could...

25 August 2020 7,261 3 View

Why am I getting negative values for antioxidant assay standard curve?

I am trying to get a standard graph for antioxidant activity of ascorbic acid using 0.1 mM DPPH solution. I had used 100 ug/ml stock and serial dilutions were from 1 ug/ml to 10 ug/ml. All of the...

07 August 2020 1,835 3 View

What Solvent is appropriate for DPPH when extracting with ethanol?

I am working with seaweeds. I am using using ethanol as my extraction solvent based on preliminary experiment and using methanol to dissolve my DPPH, should I expect any difference than, when I...

09 July 2020 1,052 14 View

Why there is no color conversion of purple color to yellow while working with bitter gourd fruits dry powder by DPPH assay??

Why there is no color conversion of purple color to yellow while working with bitter gourd fruits dry powder by DPPH assay??

20 May 2020 6,010 5 View