Why and how to avoid negative values in optical density by spectrophotometry when measurements corrected by blank solvent?

I am trying to assess chlorophyll-a content from coral tissue using spectrophotometry (with SPECTROstar Nano, BMG). However, I always seem to obtain some negative values in my optical density raw...

20 January 2021 1,542 4 View

Could anybody provide insights the best tools to create a custom database for taxonomy assignment of metagenomic data?

I am interested in the different tools that can be used to create custom databases for targeted sequencing and how to trim the databases based on the amplicon size? Also, should custom databases...

02 December 2020 3,105 3 View

How can I transfer heat between groups in Gromacs?

Is it possible to transfer heat from one group to another using simulated aneeling technique in the Gromacs software? I would like to transfer heat from a gold nanoparticle (group 1 from 310 to...

20 November 2020 9,062 3 View

What are some economic incentives that make sustainable mining processes economically valuable for companies and communities?

Mining plays a significant role in regional development. It also generates great amounts of waste -- some of which contains toxic chemicals and heavy elements. Yet, additional mining-related...

11 August 2019 7,179 4 View

Does noise affect, or compound, mercury poisoning in the human body relative to small-scale gold mining?

On-the-ground experience would suggest that sound/noise pollution and mercury contamination may be coincidental in artisanal and small-scale gold-mining stakeholders and their bodies. If so, does...

31 July 2019 5,350 1 View

How can isolate red blood cells from non-heparinized blood stored in liquid nitrogen?

I am working with a fish and I want to measure the amount of DNA in the red blood cells using flow cytometry, to estimate the genome size. However, the blood from which i am trying to isolate the...

01 February 2019 3,548 3 View

How can I measure proliferation in co-culture without detaching cells?

16 February 2017 682 3 View

Who works with antimicrobial peptides used as antibiotics to treat lung infections?

Trying to make connections!!!

26 January 2017 5,283 4 View

Possible reasons for odd OD results in 24-well microplate?

I have recently started culturing different phytoplankton species in 24-well microplates and taking absorbance measurements using the microplate reader FLUOstar OMEGA. Surprisingly, OD data for...

13 June 2016 9,214 4 View

If I can not find the contact details of a researcher and I need to adapt and revise her questionnaire, what are the other ways to make this possible?

24 February 2016 6,605 3 View

Looking for Materials with high thermal expansion coefficient and high temperature resistance?

03 March 2021 8,272 1 View

How to grow E.coli on the low salt LB agar plate with 50 or 100ug/ml of Blasticidin?

Hello, I would like to ask how to grow E.coli which resists 50 or 100ug/ml of Blasticidin. I have tried many methods by using low salt Luria-Bertain(LB) agar plate. However, no colonies grow. Let...

01 March 2021 2,027 2 View

Energy minimization in LAMMPS using NVT ?

How do I do energy minimization in lammps with NVT ensemble ? I am using the following command and it does not seem to work. It stops at extremely high energy and gives me the error zero search...

01 March 2021 2,294 3 View

Why is the sum of the elements in a row in a Q matrix equal to zero?

When explaining substitution models, the substitutions are expressed as Q matrix. Why is the sum of the elements in a row zero?

28 February 2021 3,864 3 View

Are there lab markers/pens resistant to Roti-Histol?

Hi, I'm looking for a pen/marker to write on the smooth, transparent (non-frosted) part of microscopy slides which does not get washed away by alcohols and most importantly Roti-Histol. I want to...

24 February 2021 9,902 5 View

Why the CHi^2 is close to zero with a bad fitting but the Rp and Rwp are still high?

I am refining my XRD data using in FullProf program. The intensity of the modulated X-ray peaks is almost flat. I tried to adjust the peak intensities but unsuccessful. What is the reason? I guess...

23 February 2021 2,304 4 View

I have a problem with kanamycin - why the kanamycin doesn't affect?

Hi everyone, I need to expression of GFP with pET28 plasmid in E. coli BL21(DE3) plysE. Transformed cells have kanamycin and chloramphenicol resistance. Normally, only transformed cells should...

22 February 2021 4,032 4 View

How does elongation affect the resistance of an electrode?

What are the testing rate for electrodes recommended by ASTM for cochlear implants. I am currently doing the 15mm/min elongatio testing.

22 February 2021 1,515 1 View

Resistivity of PVD TiNx thin films vs. N2 flow?

In the PVD of TiN thin films (~100A), I've found the resistivity of the TiN films dropped from ~100 to 60um*cm with N2 flow increasing up to the metallic mode ending point; then the resistivity...

21 February 2021 1,864 2 View

Can we use a compensation matrix with single staining that the negative population for each single staining is below zero?

Recently we used single staining to make a compensation matrix. But, for each single staining we saw that 13 to 25 percent of our negative population had been shown below Zero. In this situation...

21 February 2021 9,982 2 View