Why are lines forming in resolving gel of SDS-PAGE and preventing separation of proteins?

This has really been quite frustrating. Every time I load my samples (20 to 45 ug per well), I see lines form in the resolving gel and they interrupt the run. The proteins just accumulate on that...

11 December 2019 7,305 10 View

Why is m9 medium turning yellow?

I prepared M9 medium by autoclaving the M9 salts and glucose separately. Calcium chloride, magnesium sulfate, and trace minerals were dissolved in autoclaved water and sterilized by filtration....

05 June 2018 4,688 4 View

What is the best solvent to dissolve p-coumaric acid?

Any suggestions? Perhaps in NaOH and the neutralize to pH 7. I need the pH to be around 7 in the final solution.

01 February 2018 5,332 8 View

Substrate concentration lower than Km?

If I am using substrate concentration that is much lower than the reported Km of an enzyme, say for example 30x lower, is there a way to compensate for that? Can I just add an excess of enzyme...

31 December 2017 4,579 3 View

Two compounds in solution absorbing at the same wavlength?

So, I'm doing an enzyme assay and there are two compounds in the assay, one a product and the other a cofactor, that absorb at the same wavelength. It makes it very difficult for me to detect...

31 December 2017 3,510 3 View

How do you quench NADPH in enzyme assays?

What kind of chemical agents can I use to oxidize NADPH in a reaction and stop an enzymatic reaction? Suggestions other than chemical agents are also welcome. Thanks!

31 December 2017 1,601 5 View

How do you regulate antibiotic resistance gene expression?

When you have an antibiotic resistance gene in a plasmid, how do ensure that the enzyme is constitutively expressed so that your selection always works?

10 November 2017 5,123 5 View

Enzyme assays can't reach Vmax?

I am doing some enzyme assays with a non-native substrate of an enzyme. At a certain concentration, it seems to plateau (as if reaching Vmax) and the graph resembles MM kinetics but when I try...

07 August 2017 2,109 15 View

Is the best way to report enzyme activity Km and Kcat or specific activity?

I've been thinking a lot about this question of late. I suppose most people determine kinetic parameters in terms of Km and Kcat to see how well their substrate is catalyzed by an enzyme. But if a...

05 June 2017 4,984 11 View

Calculating Kcat from Specific activity?

05 June 2017 2,354 0 View

How two melting peaks in DSC of polypropylene can be merged into one crystallization peak?

The figure shows DSC cooling (blue) and 2nd heating (green) curves (step: 10 K/min) for a commercial sample supplied as Atactic Polypropylene (APP). The heating curve illustrates two major...

03 March 2021 5,857 3 View

What are the countries most affected by extreme rainfall as a result of climate change?

Increased heat, drought and insect outbreaks, all associated to climate change, have increased wildfires. Decreasing water supplies, declined agricultural yields, health impacts in cities owing to...

01 March 2021 7,168 9 View

How can you bring two structures together to create an adhesive bond in LAMMPS?

I have created an Ice 1h crystalline structure and an Aluminium substrate structure and equilibrated both at 250K. Now I need to bring them together in a way that an adhesive bond is created....

01 March 2021 3,325 2 View

What is recommended for solid domain in ANSYS FLUENT?

Should I mesh the solid domain ? or should I use wall thickness? or Shell conduction? for Heat Transfer between two fluids of a Heat Exchanger. what is recommended?

01 March 2021 9,785 3 View

Precipitate after adding laemmli buffer to protein solution containing Potassium Acetate?

Hi, I am running a size exclusion chromatography experiment with a buffer containing Potassium Acetate as a salt. I analyse these fractions through SDS-PAGE. After boiling my SEC fractions in...

01 March 2021 2,622 3 View

Heat exchanger with liquid Nitrogen as coolant?

I want to cool Natural Gas from 195 Kelvin to 138 Klevin in a heat exchanger by using liquid nitrogen as the coolant medium. When entering the heat exchanger, the liquid nitrogen will have a...

01 March 2021 6,450 5 View

How can i resolve the "final solutuin is not converged" error in Comsol for my heat transfer simulation??

I have been trying to simulate heat transfer problem in Comsol 5.5 for long time but it always throw an error stating: "Failed to find a solution. Maximum number of Newton iterations...

28 February 2021 8,626 3 View

Necessary tube lenght to cool Natural gas in a dry-ice cooling bath?

I have a tank which contains natural gas at 250 Bar and 293 Kelvin. I want to cool the gas in a dry-ice cooling bath to about 195 Kelvin. The gas will flow in a copper-tube through the bath with a...

27 February 2021 8,128 1 View

Exit velocity of natural gas from pressurized tank?

Hi Guys. I'm a mechanical engineer and have a bit trouble, would be very glad if you could help me with my questions. I have a pressurized tank which contains Natural Gas at 200 Bar and 293...

26 February 2021 6,253 3 View

Can thermal cycler machines be problematic during PCR?

Hi, my question is about the heating of thermal cycler machines and I hope some of you had experienced a similar thing previously. There are two thermal cycler machines in the lab(BioRad) and for...

26 February 2021 4,777 4 View