Quenching - Science topic

The shaft has a 10 mm diameter, the bushing is 2 mm thick, and their contact length is 30 mm. I understand this is technically possible, but has it been tested, or does the material become too brittle and crack in use?

Quenching and partitioning

Hi all, I'm trying to image some tissue that has Tdtomato onboard, and would like to quench/kill these. I can't use heat antigen retrieval to kill these fluors, and I've explored UV light exposure (up to 30 min), bleaches it, but then it comes back with time. I've also tried H2O2 in PBS, also at pH6.5, and similarly, signal goes down, but it recovers. Any suggestions would be appreciated!

Hi everyone, I am studying the photoluminescence (PL) quenching of a complex A1-D-A2. After using electron-hole analysis, for the 1st state, the electron transfers to A1, and for the 2nd state, the electron transfers to A2; both are dark states. Can I ask which one will cause PL quenching? In the experiment, the A2 had better electron withdrawing ability. Thank you

add yours valuable comment.

Hi, I am performing an enzyme activity assay where Fluorescence is quenched upon successful conversion of substrate to product and the it is an endpoint assay. How do I calculate % activity or % inhibition in this case?

I was performing quenching studies in solution state. While plotting the Stern-Volmer graph, which intensity should I use as initial intensity (I₀).

For example, I take 1 ml of 0.1 M fluorophore solution and add 1 ml of analyte solution in different concentrations. The resulting concentration of fluorophore in the mixed solution will be 0.05 M.

Should I consider 0.1 M or 0.05 M as the initial solution?

Hello, I am trying to fix primary cells with glutaraldehyde. I am trying to stain cell membrane proteins and I have not been successful with PFA and methanol fixation. Does anyone have a protocol for glutaraldehyde fixation (conc., time, quenching etc.)?

Thank you!

I am studying the interaction between carbon dots and fluorescent organic dyes like Rhodamine 6G, which have an overlap between the emission of the CDs and absorption of the dyes.

In spectroscopic analysis, as I increase the concentration of the dyes in the CDs solution, the emission peak quenches, while the fluorescence lifetime increases as the concentration of the dye increases. Additionally, the emission intensities of the dyes increase. In a typical FRET (Förster Resonance Energy Transfer) process, the emission of the carbon dots is expected to decrease, and the emission of the dye is expected to increase. This is happening with my samples, but the fluorescence lifetime of the CDs is expected to decrease. However, in my CDs sample, the lifetime increases as I increase the amount of the quenching dyes.

Can you please share suggestions to understand this anomalous observation?.

I want to ask about the response of the analyte in the EIS measurement. Bare shows a high Rct response as compared to material-modified electrodes. But when we modify the material + analyte, the Rct value response decreases. What is the reason for that? According to my knowledge, it would show a higher Rct response than material, & in CV, it shows less response than material (quenching).

I have a fluorophore and its emission is quenched on adding analyte compound. The overlapping spectra of compound and analyte make UV-vis absorption analysis unreliable.

The analyte mixture spectra shows larger absorbance value than fluorophore compound.

Although I depend on emission spectroscopy for the quenching constants and etc.

I'm curious to know if there are any possible computing methods to overcome this problem and making the absorption spectrums useful for my purpose (explaining emission quenching)?

I oxidised pure Mg powder in an atmosphere of O2 and He, at low heating rates (between 0.5 and 1 °C/min) from 20 to 800 °C.

From microscopic observations of quenched samples, I saw that Mg, which has initialy a silver color (first picture), turns black at the beginning of the oxidation process (second picture), and then turns white (classic MgO).

This black layer looks thin, while the white oxide is like pop corn.

Any idea what could be this black layer ? I guess it's a kind of intermediate oxide species (Mg2O ?)...

The only information I found in the literature is that it could be a Mg:O phase, 80:20 in mass repartition.

Thank you,

Can BHQ quench the fluorescence of FAM in the case shown below?

As I was analyzing an emission quenching data, I came across the term integrated sv plot. I have heard about the "normal" sv plot. Please give me some insights on this. Also, does anyone know which one is preferred and why?

Thanks in advance for your help.

I know difference between dynamic and static quenching but i cant understand What is the importance of distinguishing between these two types of quenching?

Dear Genius Researchers,

I would like your guidance if anyone can help me in model (Numerically) pool boiling heat transfer phenomena. I am working on Mathematical modeling of "Quenching process", and stuck in lot of theories, still unable to find way to model the "convective heat transfer coefficient" during pool boiling in quenching a steel specimen.To make it simple can we use one dimensional FE method in doing so...? Please share your expert opinion and guidance.

Thanks

1. Suppose a large BF is being fed with Dry Quenched Coke. Suddenly , a breakdown occurs either in the Cove Oven Battery, or in Coke Dry Cooling Plant or in the transport route. The coke feed to the large BF has now to be changed to the wet quenched weathered coke from stock. What precautions need to be taken to ensure safe operation of BF in such scenario ?

2. A large BF is being operated at very high PCI Rate (150-200 kg/THM) and suddenly such a breakdown occurs that total PCI has to be suspended. What immediate actions must be taken for safe operation of BF in this scenario?

You may share some actual experience at your BFs also, if possible.

Temperature change rate should not exceed 150 °C/Hr for Alumina Crucible. Which material can withstand higher temperature change rate showing good thermal shock behavior.

The lesser the moisture in coke, the lesser the Coke rate in Blast furnaces and hence lesser fuel cost. In order to decrease the coke moisture, various parameters need to be controlled. A few Coke Plants have shifted to the latest Coke Dry Quenching process while many still rely upon the Wet Quenching Process. I would like to know what all parameters need to be considered to achieve the same in the case of Wet Quenching process. What factors cause coke to absorb moisture when quenched.

I hope you're well. I'm struggling to differentiate quenched glass from crystal minerals in high-pressure/temperature quenched glass samples. Seeking your expertise to distinguish from crystal minerals. Seeking your expertise to distinguish from crystal minerals and wondering if you could share insights on recognizing quenched glass. Any guidance on visual, chemical, or physical distinctions would be appreciated.

I'm looking forward to your reply. Thank you for your time.

Hi

Usually, AIQ has an effect on the emission spectrum. What about absorption?

Does aggregation-induced quenching (AIQ) impact on the absorption of CQDs?

For researchers familiar with the study of decarburization: In a high-speed machining process applied to carburized quenched steel, where machining temperatures are predicted to be near A1 and of short duration, could decarburization take place on this workpiece surface?

In general we see that the highest absorption wavelength of a solution is the probable excitation wavelength in fluorescence. But I am seeing quenching behavior at lower excitation wavelength for my sample. What could be the possible reason? Any literature suggestion would be highly appreciated. Thank you!

Experiments studying the extent of different quenching changes under a series of light intensities require a 30-min dark-adaptation of leaf to get the Fv/Fm value, which represents the relaxed state of the leaf. But it's really time-consuming to conduct when there are multiple groups to measure. Then would it be reasonable to replace this value by the maximum Fv/Fm obtained at predawn when the plants are fully relaxed? And wouldn't the Fv/Fm from predawn be better since it excludes the impact of all the potential factors that possibly reduce the Fv/Fm during the diurnal time?

Which oil is used for quenching of modified 9Cr-1mo steel (P91/Grade91 steel)? Can anyone suggest the name of the quenching oil?

Well, I found a paper pretty old, 2001, that shows a decrease in the DCFH-DA signal. Is this decrease a quenching effect? Or another phenomenon but never a measurement of antioxidant enzymatic.

What do you think?

help me a little bit whit this, OP

hello;

In my research on calculating the minimum ignition energy analytically, I need Jet A-1 fuel properties, especially the quenching distance, viscosity, and flame speed, which are expressed as a formula in terms of temperature or pressure, so that I can calculate the minimum ignition energy by placing them in the main formula.

But I did not find enough information about the mentioned fuel. Can anyone help me?

I use MCF7 cells to overexpress my protein of interest tagged with RFP using Polyethylimine. Then I stain my cells with monodansyl cadeverine(Specific for Autophagolysosomes)(50mM) which is dissolved in DMSO, following this I fix my cells with 4% paraformaldehyde, then followed by Hoechst staining. I'm not able to pick up RFP fluorescence right after my MDC staining. RFP fluorescence could not be captured either in the control which is over expressing RFP (added 200ul of DMSO per well without stain) or in the treated which is over expressing RFP tagged protein, right after the addition of staining solution. Could the volume of DMSO added have any effect in this situation?

Hello,

I am using ThS fluorescence as an indicator for tau aggregation in kinetics assays. This has been working really well, but I have now started to use the same assay to investigate the effect of a tau-aggregation inhibitor, which is blue when oxidised and clear when reduced. The inhibitor quenches the signal in my assays, and it seems that the signal is quenched significantly less when the inhibitor is reduced and in its clear form.

This has lead me to optimising my assay to minimise oxidation in my assay, using DTT in the sample, preparing the assay in a glove box with nitrogen and using lower amounts of the inhibitor. However, I am still getting quenching of the ThS signal.

Do you know if there are any other amyloid-detecting dyes that will not be quenched? Or, any more ideas to minimise oxidation in the reaction and keeping the sample clear?

Thank you!

During the quenching process, austenite transforms into martensite. Usually, there are 3-5 martensite packets in one austenite grain. But why the number is 3-5?

Hello everyone,

My mind is occupied with an issue. I wanted to discuss that with you.

As you know, in case hardening, carbon atoms diffuse in the subsurface of the steel and lock there when the steel gets quenched afterward. The resulting martensitic structure hardens the surface, so we benefit from the hardened surface + toughness of the core.

But consider the situation when high-temperature alloys are used in the petrochemical sector, carbon atoms liberated from the hydrocarbons in the coils, diffuse inside the structure and then combine with the metallic atoms and form carbides.

The problem is these carbides. What is the difference between case hardening and carburization in the petrochemicals sector that the first is an advantage wheras the second is a catastrophic event?

What do these carbides do with the structure? Where exactly do they form? at grain boundaries or inside grains? how do they induce corrosion? what type of corrosion occur? I hope you participate in this discussion. Thank you in advance

I am doing heat treatment of ZA27, wanted to change the quench media. Air , water and an oil.

Biophysical assay involves cleaving a quenched fluoregenic substrate that results in increased fluorescence. Difference between racemic mixture and pure components came to be ten times different in terms of IC50!

I am using a tube furnace to anneal the sample in presence of Argon. Can I do sudden cooling after the heat treatment over at such high temperature? Will it be any problem to the furnace?

Initial fluorescence emission intensity is quenched with the addition of an analyte, with time, gradually fluorescence intensity increased. What may be the reason?

Dithionite quenches NBD. I am searching for a chemical quencher of Octadecyl Rhodamine B.

What is the best method to prepare a sample for EBSD analysis of 410 martensitic stainless steel? samples were quenched and partitioned and the structure consist of austenite + mertensite, ...

I need to quench 1 L of Pyridine as it is past the expiry date. What would be a safe way to do so?

In my project, I am trying to show Staphylococcus aureus in endothelial cells with fluorescent dyes. But when I used calcein AM, due to the presence of esterase enzyme in the bacteria and the cell, both are seen in green color, and it is not easy to recognize the intracellular bacteria.

I am currently working on a project that involves photo-activation of fluorophore containing probes to spatiotemporally tag the surface of cultured cells or fixed tissue. There are two photo-activated probes we are working with. One has an azide species and the other is a primary amine. The tagging works well with live cells but has a very high background with fixed cells. To try to overcome this, I tried to quench the PFA Schiff base moieties with 0.1% sodium borohydride, 2M glycine, or 1M pH 8 Tris. The Tris works relatively well with a 1 minute quenching procedure for the azide reactive probe species, but the other quenching agents haven't worked at all. I have not been able to reduce the background for the primary amine reactive species with any quenching agent yet. Next I plan to try to reduce and alkylate the cell surface with DTT and iodoacetamide after an initial PFA quenching procedure. Has anyone experienced this reactive nature post PFA quenching and are there any suggestions on how to successfully reduce the surface so that the photo-reactive specifies won't readily couple with cells before UV activation?

I'm running a pretty standard click reaction in whole cell lysate (1mM copper sulfate, 1.2mM THPTA, 5mM sodium ascorbate, 1mg/mL protein) at room temp and quenching with EDTA. I follow this with a clean-up in Zeba-spin columns to remove my Cy3-azide probe before preparing the typical gel sample. I've been able to get specific labeling in the reaction, but every time I stain the SDS-PAGE with coommassie I discover that the protein has bunched up at the top of the gel, and very little has run down the lane. I've gone through some trouble-shooting to check if I was boiling the gel samples at too high a temperature or if I needed more EDTA. The only thing that prevents the bunching is not adding the copper at all, which obviously means there is no click reaction.

Has anyone run into this problem? Should I be removing the copper in another manner before making gel samples? Should I be using less copper, more THPTA, some other protectant for my protein?

I am trying to lithiate the two following ligands for attachment to 9,10 diboraanthracene. Upon addition of the tbuli slowly to the ligand, the color changes and the lithiation seems to occur. But after adding the lithiated ligand to the DBA, the ligand always seems to get quenched (proton replaces Li) instead of reacting with the DBA (shown by NMR and mass spec). My current procedure is such:

1) Dissolve the ligand in dry et2o (THF kills DBA), cool to -78 for 10min.

2) Add tbuli dropwise, let stir at -78 for 1 hr.

3) Transfer the lithiated ligand via cannula to a second flask holding DBA dissolved in either toluene or 50/50 ether-pentane at -78C (second flask is also cooled for 10min prior to addition).

4) Let stir for 2 or 18hrs (I have tried both) while warming up to RT.

**All solvents are tested for O2 and H2O with sodium benzophenone indicator before starting; all dry reagents are kept in a N2 glovebox**

I've done successful lithiation reactions before, I know how to do them. I am trying to figure out if there is some additional way to try and get the lithiated product to not get quenched. Should I run this at a lower temperature? Should I change solvent?

Thank you

I have frozen tissue sections from mouse brain/spinal cord, expressing a germline GFP in my cell type of interest and AAV-driven tagRFP in infected cells. This is great for looking at the spread of my injection and colocalization with cells of interest, yay!

The difficulty I'm having is that, for questions separate from my cell type/infection, those fluorescence channels are obviously occupied by the GFP/tagRFP expression. 4% PFA fixation did not do much to quench their fluorescence, I can see the signal bright and clear without any staining.

Is there a way I can quench/photobleach this signal reliably, to free up the GFP/RFP channels for labelling different peptides on these sections? I have some antibody panels where I would really like to use red and green fluorophores to label different proteins of interest, but cannot do so reliably with such high "background" fluorescence from these genetically encoded fluorophories.

Thank you!

Hi! I'm trying to quench fitc fluoresc from Cryptococcus stained with FITC ( at 0,1mM in PBS, 30min, RT) using trypan blue at different concetrations, up to 0,4%.

I'm trying to padronize a phagocytosis experiment by FACS in RAW264.7 mac cell line. First Crypto are stained, washed and co cultured with RAW. The assay looks to differentiate phacocytosed funghi from attached ones by quenching fitc fluoresc from cellls that were not internalized using Trypan blue followed by aquisition by FACS. The point is that , althought it seems to be a something easy, I canot see a substantial efect in fitc quench other than a low reduction in median fluorec intensity compared to not stained cells.

Anyone have an ideia of what might be going on?

tks!

I'm looking for safe ways to quench a 50-ml heated glass RBF from 200 °C to room temperature as fast as possible. I appreciate it if I get some ideas around the possible ways.

Dear all,

Can you please explain me with your experiences why there is an increase in Dissolved Organic Carbon / Total Organic Carbon after treating my water samples with oxidants like Chlorine and Ozone. I am giving a reaction time of 15 minutes and then quenching my excess oxidants (Ozone - Nitrogen gas, Chlorine - Sodium thiosulfate).

During martensitic transformation, some austenite remains in the matrix and does not transform into martensite. In the same material, for example 410 martensitic stainless steel, what parameters can lead to a higher level of austenite remaining after quenching?

I am trying to quantify bacteria based on the fluorescence emitted by GFP expressing bacteria. I want to quench any background fluorescence from the media to make sure that my fluorescence data really reflect the no. of GFP expressing bacteria and not for the media in which bacteria are grown. Any suggestions greatly appreciated. Thanks

Just received a major revision decision on a article submitted to an international journal with a high impact factor. The reviews are contradictory, one applauds our efforts and other is very critical. I am in a dilemma now, how do I balance the two reviewers and at the same time hold my ground of argument to quench my thirst for a novel contribution?

Triplicate peptide samples were dissolved in human serum at a concentration of 100 microM and incubated at temperature of 37 C. Then, the aliquots of each peptide were taken out at 0, 12, 24, 36, and 48 h. Each aliquot was quenched with 6 M urea and incubated for 10 min at 4 C. Then, 20% TFA was used to precipitate serum proteins for an extra 10 min at 4 C. All aliquots were centrifuged at 14,000 g for 15 min, and the supernatant was analyzed by RP-UPLC using a linear gradient of 5–30% buffer B for 5 min.

We are told that the alloy in question is primarily made of copper but also contains som silver or gold and we are asked to calculate the composition.

The diffraction peaks seem to match very closely with pure copper so i assume the alloy must be made of a pure phase but unsure how to say if it is alph copper and gold or a quenched beta phas copper silver alloy?

Hi, I would like to know if Biotin quenches fam in a ssDNA-FB reporter. Please share some supporting literatures if available. Thanks in advance.

My sample's fluorescence were quenched by Mn2+, why is that? thanks!

Is static quenching constant is same as the Stern Volmer constant? I have found static quenching mechanism in our case, want to know how to find out the KS value from graph?

The only information I got is to not include reducing agents in the sample processing. Is there any specific details needed to be care about? Should I use NEM to quench free thiols before run SDS-PAGE? If the complex is larger than 160kDa, should I add some specific reagents such as SDS in the trans buffer?

What can be the possible reason for an increase in fluorescence lifetime when there is a quenching of fluorescence intensity upon addition of analyte into a ligand?

I have a question regarding the use of Stern-Volmer equation to analyze fluorescence quenching in a displacement experiment. When the interaction of two molecules (one could be a macromolecule like a protein) leads to the decrease of fluorescence intensity of one of them, we use Stern-Volmer equation to analyze and study the mechanism of the quenching and interaction. For example, a ligand binds to a protein and quenches the fluorescence of protein (arising from fluorophore residues). Then we may calculate quenching constant and conclude based on the results that it is a dynamic or static quenching. Here the quencher and fluorophore interact with each other and everything is fine. But in situations like Hoechst-DNA complex, which leads to fluorescence emission, when we add a tired molecule which displaces Hoechst and leads to fluorescence quenching, how it is possible to use Stern-Volmer equation to get a quenching constant and then interpret the results and comment on dynamic/static quenching mechanisms. The tired molecule interacts with DNA, not with fluorophore which is Hoechst in this case. In such cases what we see (the intensity of fluorescence) is the result of interplay between binding constants for Hoechst-DNA complex and for tired molecule-DNA complex and the condition just apparently can be analyzed by Stern-Volmer equation. Unless, we accept that Hoechst-DNA complex is so stable that the quencher interact with the complex and quenching happens, and then displaces Hoechst. But, in fact, the quencher interacts with free DNA and shifts Hoechst-DNA interaction equilibrium towards more free Hoechst, which in this case there is no direct interaction between fluorophore and quencher. Of curse, the fluorescence intensity (as a detectable signal) for the titration can be used to get the binding constant of the tired molecule to DNA, like any other competitive binding experiment (where the spectroscopic or non-spectroscopic signals are monitored), but in my view, commenting on quenching and mechanism of quenching seems irrelevant in such cases.

I will appreciate it if you could kindly let me know if I am correct and what is the best way to explain this situation.

what temperature required for Poly-propylene quenching to enhance its tensile strength which comes from extrusion molding process and combine with polyester fibers

The material is 7075 aluminum alloy, which is quenched by 470 ℃ / 24h homogenization treatment, followed by 30% cold rolling. The metallography is shown in the figure below. I want to know what caused it. Thank you.

I tried both FAM-aptamer and Texas red-aptamer (1 ul of 100uM, dilute with 200 ul PBS). When I add 500ng protein (5 ul) to the solution, I found the fluorescence from dye was about 15% decreased. And the protein is not the specific target to our aptamer. Does anyone know why?

Many thanks!!!

I am doing subzero heat treatment after quenching for en24 steel. And after subzero heat treatment am tempering it for 450c. So is it ok to go for 6 hours for subzero heat treatment or do we have to go for 24 hours only? 

Our quantum dot(g-C3N4/CQDs) was prepared from melamine and then exposed to phenylbronic acid(PBA) for the next steps of the experiment - whose fluorescent properties were quenched (Figure 1) but after 5 days and quantum dot solution dialysis with PBA (1000D) A little of its fluorescent property back, what is your analysis?

I would like to anneal two RNA oligos with one of them tagged with FAM and another with TAMRA. The TAMRA should quench the FAM emission, but I keep seeing high signal levels although it is lower than FAM only. I have confirmed that the wavelength that I was detecting does not have a signal for TAMRA only.

I think it may be because the annealing was not successful but I have tried several annealing conditions and the quenched RNA emission level is still high.

I also tried doing everything under a really dim red light but annealed oligo still had a high signal (lower than FAM only but not so much lower).

What the problem it could be?

Thank you so much!

I have lung cancer biopsy slides that show auto-fluorescence (FITC) how do I quench or overcome the fluorescence?

Can you please help me in calculating the concentration of this methylene blue solution in g/L or mol/L?

Methylene Blue Solution- 0.05 wt. % in H2O

How can I identify the quenching mechanism acting on a protein-ligand interaction from Uv-Vis data?

Attached is the Uv spectra

Is it possible to calculate the quenching rate constant in the absence of a lifetime measurement value?

Hi Everyone!

Please can anyone recommend to me what protease(s) I can use to proteolyze my green fluorescent protein (GFP), that can lead to its loss of fluorescence?

Trypsin and chymotrypsin were reported not to bring about quenching of the fluorescence.

Thank you

My experiment is Surfate based AOP with Co, Cu, Fe catalyst.

I know that Methanol is usally added to quench the reactoins, however, it has some problems when analyzing the TOC

I tried to use KI but it cause some precipitate problem.

So, is it okay to use sodium thiosulfate?

It has been already reported that the sample has an inversion parameter that varies depending on the quenching temperature.

However, for a sample made in a particular quenching temperature, I want to find out how to calculate this value of inversion parameter from any experiments like XPS or XRD or any other mode.

Thank you

I have calculated the inherent structure of liquid TIP4P/2005 water system and simple Lenard-Jones liquid also. I used conjugate-gradient method for it to minimize the energy. After that I performed normal mode analysis by generating Hessian matrix . After diagonalization I got Eigen values of Hessian matrix. But for quench configuration or inherent structure configuration I am still getting some negative eigen values. It is not expected that in quench configuration or energy minimise configuration we get negative values of Hessian. Some suggestions from you could be helpful for me...

I request you to suggest me something.

In maraging steels Fe and 18 to 22% Ni is using, this steel is quenched fully martensite is forming depending upon Ni content. Ni is a austenite stabilizer, why retained austenite not forming in these steels.

Hi All,

I'm currently using a viral vector to express a protein labelled with mCHERRY.

Upon infection of cell culture, I'm trying to fix and stain with an antibody labelled with mCHERRY.

Unfortunately, I'm unable to tell the difference between residual mCHERRY left from viral vector infection, and the mCHERRY fluorescence from the (mCHERRY) antibody i use when staining.

We usually fix in 80% acetone (30 min, 37 degree), but I've also tried fixing in 100% methanol, and 50/50 methanol/acetone. None of these appear to quench mCHERRY fluorescence from the viral vector.

I'm able to easily quench GFP (virally expressed, but not linked to anything) through 80% acetone fixation, but I'm having trouble quenching the mCHERRY when linked to my protein.

Sorry about the vagueness, there are some patent issues with this. Just know that I can't change the mCHERRY-antibody I'm using to stain with.

Appreciate any help you can give!

Fluorescence spectra of BSA with cerium oxide nanoparticles are quite good. But what bothers me is that Ka increases with temperature, which is unexpected for static mechanism of the quenching. Is there any possible physical explanation or maybe we did not take into account sth? Has anybody encountered that in similar research?

I have tried to use K2CO3 as a base catalyst and DMF as the solvent. The reaction was hold at 70 degree C overnight. The reaction was quenched by ice water, but it seemed that the yield was so low, and trivial amount of polymer precipitated out.

Is there a better reaction pathway I can try?