Science topic

Luminescence - Science topic

Emission of LIGHT when ELECTRONS return to the electronic ground state from an excited state and lose the energy as PHOTONS. It is sometimes called cool light in contrast to INCANDESCENCE. LUMINESCENT MEASUREMENTS take advantage of this type of light emitted from LUMINESCENT AGENTS.
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The context: The measurement of ATP using firefly luciferase is the most commonly applied method for estimating the number of viable cells in HTS applications. ATP has been widely accepted as a valid marker of viable cells. When cells lose membrane integrity, they lose the ability to synthesize ATP and endogenous ATPases rapidly deplete any remaining ATP from the cytoplasm. Although luciferase has been used to measure ATP for decades (1), recent advances in assay design have resulted in a single reagent addition homogeneous protocol that results in a luminescent signal that glows for hours.
In my case I use the 3M™ Clean-Trace™ ATP Monitoring System for ATP detection of surfaces in a very delicate environment: a hospital. As you can imagine the quality of hygiene in a hospital is a very delicate and important job, as a complement to the daily task of cleaning, the work of hygiene detection is a control to check the efficiency of disinfection, and a good way to ensure that nosocomial diseases will not proliferate in high-risk environments such as ICU, operating room, etc..
BUT, in my company's R&D group teams there are multiple opinions that this ATP detection mechanism does not detect LIVING or VIABLE cells, they think it only detects ORGANIC MATTER, and it does not matter if it is alive or not to contain ATP. In my opinion, only living matter produces ATP, and in dead cells there is a rapid decomposition or hydrolysis of ATP to ADP, which is naturally spontaneous and energetically favored (It is a very exergonic reaction) (2).
The question: Who is right? Does the detection of ATP on surfaces determine the existence of VIABLE CELLS or ORGANIC MATTER (including dead and/or living cells)?
Equipment: 3M™ Clean-Trace™ ATP Monitoring System (3M™ Clean-Trace™ Luminometer LX25) https://www.3m.com/3M/en_US/p/d/v000236906/
E-resources:
Literature:
1) Hall MP, Gruber MG, Hannah RR, Jennens-Clough ML, Wood KV. 1998. Stabilization of firefly luciferase using directed evolution. In: Bioluminescence and Chemiluminescence—Perspectives for the 21st Century. Roda A, Pazzagli M, Kricka LJ, Stanley PE (eds.), pp. 392–395. John Wiley & Sons, Chichester, UK.
2) Gajewski, E.; Steckler, D.; Goldberg, R. (1986). "Thermodynamics of the hydrolysis of adenosine 5′-triphosphate to adenosine 5′-diphosphate" (PDF).
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Francesc Felipe I did an experiment last week and I found great differences in ATP content in surfaces before and after using UV-C light in a dirty operating room. I will report more soon :-)
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In case of the chemiluminescence signal representing the quantitated value of the target expression. Does an increase of the exposure time to 64 folds of A to reach a similar signal as B; does this mean that B is 64 folds enriched than A?
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Ideally, that would be the case, but there are reasons why it may not work out. One is if any of the pixels get saturated. Another is if the luminescence is not constant over time, which it probably isn't because the reagents are consumed by the light-producing reaction.
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I have generated cell proliferation luminescences OD value of breast cancer cells. Now, I am trying to calculate CI value with compusyn software. Can anyone help me to convert OD into effect as compusyn software only takes a value of 0-1 but my OD values are in hundred to thousand range.
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Why are you using OD values for luminescence? It seems as if you are using film OD for luminescence and thus risk saturation effect problems. I suggest that you use the actual light emitted (luminescence) values and, after subtracting appropriate blank background, and assuring that the luminescence of each cell is equal, take the ratios on the growing cells mean value at each time point relative to that of the original day zero value (use equipartition of variance to get the appropriate precision estimates of the ratios) and plot their values on a semilog plot as a surrogate of cell growth, which is what I assume that you are seeking to measure and compare.
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I often run many Southern Blots at the same time, but on the last day I am having trouble getting good images because the chemiluminescence imaging machine (FluorChem) begins to overheat and artifact forms over the lens, so I would like to find a last day step (ex. blocking, washing, detection buffer) that can be extended overnight so I can image some membranes the following day. Does anyone have experience letting any of these steps extend? I have seen literature suggesting blocking overnight at 4 degC; does anyone know the upper limit of time that membranes can be left blocking at 4 degC, and if the membrane should be on a Nutator/shaking?
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Though I don't have much experience with Southerns, this practice is really common for Western blots. I typically leave the membrane in blocking solution overnight at 4°C with shaking/nutation. Your enemy here is mircobial contamination, so usually I filter sterilize the blocking solution and/or add some NaN3 as a preservative (obviously very toxic, use caution!). Make sure the blot is well covered to prevent dust and contamination. It's generally not advisable to leave the blot for extended times in antibodies (in your case oligo probes) as this will increase background. But I've left a blot in blocking over a weekend with no effect on the outcome.
On a case by case basis it may be completely fine to finish the blot and just image it the next day, but this depends on the fluorophore/chromophore used for detection and its half life.
Good luck, best wishes!
ACA
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I am currently performing dual-luciferase assays, to assess the impact of two mutations in the promoter of a gene in the expression of Luciferase.
As it is recommended I inserted my sequence, that includes ~ 1kb of the 5' UTR region and a bit of the first exon, in a pGL3 vector. Instead of using the Basic, I used the pGL3-promoter vector, in which I cutted off the SV40 promoter and inserted my sequence. I then inserted my mutations by site-directed mutagenesis.
However, when I read the luminescence, I am having very low Firefly readings, while the Renilla seems to be ok.
I was looking to my sequence and I have no stop codon, and the sequences from the FOXE1 promoter and Luciferase are in frame. But in my promotor sequence I have an ATG start codon before the Luciferase ATG, therefore, the transcription of luciferase may not be starting correctly since I have this "tail" of aminoacids in frame with the Luciferase starting site. Do you think that this might be the reason for the low RLU values that I am having? Or do you think it's something else?
If so, do you have any suggestions to correct this problem?
Thank you,
Carolina Pires
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Hi Uwe,
Thank you so much for your reply.
Indeed, in my construct I included ~1kb of the UTR, but I also included some nucleotides of the coding sequence, since the promoter expans to this region. Therefore I have the start codon of the gene in my construct. This way, I was wondering if the problem could be the Luciferase start codon not being correctly read because it is preceeded by the ATG from my gene.
Thank you again,
Carolina
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I wanna to find the Luminescence decay curv of Ce3+ and Gd3+ in bismuth borate glass, I have only PL data .
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Steady-state photoluminescence is typically measured using a continuous excitation source, such a Xe lamp. Measuring the fluorescence decay, on the other hand, requires a pulsed excitation source, such an EPLED or a laser with a high repetition rate. In other words, it is not possible to "find" the PL decay based on a PL spectra. Is your PL setup equiped with a pulsed laser/LED?
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How to calculate CRI and CCT values for a light emitting material ? I have the PL data at ambient temperature, PLQE values and CIE co-ordinates.
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Sir i found different formula for CCT
CCT : -437 n^3 + 361 n^2 - 6861 n + 5541.31
which one is correct?
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We are looking for a dedicated spectrometer to record the fluorescence spectra in the NIR range 900 - 2000 nm. ... Thank you.
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Thanks a lot!
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I am working on my Ph.D., Synthesis of lanthanide complex, i am confused about ligand selection !
Can Anyone Suggest a ligand? which heterocyclic Compound is best for synthesis
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An organic aromatic molecule with high content of oxygen functionalities
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Is measuring Bst Polymerase activity (by comparing it with NEB Bst Polymerase) using SYBR and FLUOstar Omega machine (because our RT-PCR machine has been broken and I'm not sure when it will get repaired).
FLUOstar Omega is a microplate reader that have function for incubation with temperature up to 65 degree C (LAMP reaction need 60).
Here is the list of detection modes this thing have:
UV/vis absorbance
Fluorescence intensity - including FRET
Luminescence (fl ash and glow) - including BRET
Time-resolved fl uorescence - including TR-FRET
AlphaScreen®/AlphaLISA®
does anyone have experience like this?
any opinion/suggestion would help alot.
Thanks in advance! :D
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Yes, it is! Just get in touch with our APAC Support Specialist Joko Logis
Joko.Logis@bmglabtech.com.au, he will help you with this.
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Hi,
im trying to compare CHD4 (about 250kDa) protein-expression in different cells. As u see on the picture, there are bands where the marker is and u see also the same bands on every single lane. I tried another protein with the same protocol and it worked fine.
What could cause this problem? Any solutions? Maybe primary AB?
Loading control GAPDH works fine.
Thanks!!
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Could you give us some more information? Is this a GAPDH or CHD4 blot?
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which includes El intensity vs wavelenth curve,voltage vs luminescence ,EQE vs current density
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See the examples of Silvaco. They already have built in example codes of LED with everything needed..
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Scattering and absorption of bio-tissue could attenuate luminescence intensity. And strong luminescence intensity is the prerequisite for an accurate lifetime computation. So Could the absorption and scattering of bio-tissue make the luminescence lifetime different from the one without traversing tissue.
Please help me to answer this question?
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If you detect the luminescence of the population that has been excited by the pulsed source, the decay and lifetie will not be affected by the scatering and reabsorption. But, in case of a strong reabsorption, you may dedect the luinescence of the population that has been excited by the reabsorption of the light produced by the laser excited population. This may be the case when one excite the sample from one side and observe the emission from the other side of the sample. In both case light scattering has an effect on luminescence dynamic only in the fs range.
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I plan to check TB growth and viability using Bac-titer Glo assay. This is a luminescence assay. Instead of recommended 96 well white walled, clear bottom plates can we use complete white plates?
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Thank You for your answer Kousalya
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One of my students asked me today what is the difference between light and chemiluminesce (ALNOUR)? I told her that light can be called chemiluminesce, but chemiluminesce cannot be called light. The light is the last edge of the fire or the coldest area far from the center of the fire, while the chemiluminesce comes from cold and the end is touched by peace. Light can carry heat, but chemiluminesce carries a soft touch, coolness and peace. The chemiluminesce is self-luminous, as is the light of olive oil. As for the heat, it needs a plug and a flammable substance. The chemiluminesce comes from eternity. I ask physicists to talk to me to complete this discussion. Perhaps the word “ALNOUR” has no equivalent in English, but I chose the closest synonyms that come close to the meaning of the word in the Arabic language.
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Light is electromagnetic radiation that can be detected by the human eye. Chemiluminescence is the release of a photon due to a chemical reaction.
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Hello researchers !
Could you please explain me or help me get the references or books about the basics and fundamentals of time decay/ PL life time/ decay time processes of PL downconversion ?
kindly help me , get some references!
Is there any standard mechanism for time decay?
How are increasing and decreasing time decay measured with a fixed excitation for a particular emission related to concentration of activator ions?
please help me understand this!
Thank you all !
With regards,
Manoj
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Here is a reference for your query...
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Visible to UV Up-conversion luminescence for inorganic phosphors can be achieved only when Laser is used as excitation source but if we want some practical application, Vis to UV up-conversion should be obtained by Xenon discharge lamp excitation. So is there any way to achieve Visible to UV Up-conversion luminescence without using Laser as excitation source?
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Dear Sumedha Tamboli,
Firstly let's pay attention to term "up-conversion luminescence" - next be UCL. Wikipedia doesn't know this tag UCL. I can suppose You mean luminescence that can be registered at two photon absorption at very intensive radiation by an adequate type of laser. The same result about luminescence You know can reach with UV emission of xenon, mercury and X-rays source also. Registered spectra should be the same. But most simple method, to my mind, to apply for your work UV-, or near UV diode lasers. Have a nice day!
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Hi everyone!
I'm looking for a good luminescense lab (OSL and IRSL methods) with affordable prices. It doesn't matter the country where the lab is located.
I will appreciate your recommendations.
Best regards.
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The best way is to look in the literature with relevant data.
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To investigate the carrier dynamics in solar cells (CdTe) by simulating what free software do you suggest ? Thanks in advance.
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Dear Abdul, kindly find the useful link for your reference:
This may perhaps help you in your context.
Best wishes!
Dinesh Kumar Madheswaran.
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Hello, I am using the Multiplex ELISA Kit For Mouse Cytokine Panel 2 (4-Plex) purchased from Boster Bio to measure the four cytokines IL-6, IL-1B, TNF-a, and INF-y. In this plate, all four biomarkers for each cytokine are present in each well.
Boster Bio and its distributor Quansys Biosciences claim that I need an imager, a microplate reader that will actually capture an image of my plate, to be able to analyze the luminescence emitted by each cytokines' antigen.
I currently do not have access to an imager of this sort, and I am wondering if anyone has been able to circumvent this issue and was still able to use a normal microplate reader? Or, does anyone have any idea for how I should go about measuring each cytokines' luminescent response with a normal ELISA reader?
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Our team could not gain access to the manufacturer's imager, but we did use an imager by Cytation to get a sort of OD graph/picture that we used to validate our dilutions were in the standard curve range. Unfortunately, we did not get any quantification date. We are then using these dilutions in a different multiplex with a more compatible plate reader.
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PL of Water Samples were recorded at SAIF-SPIHER by using PerkinElmer LS 45 Photo Luminescence spectrometer.
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dear colleague
i think that we can not speak about PL in case of water that is a liquid. We generally evoke it in semiconductors and insulators material. Nevertheless, if you mention your exciting wavelength we can can more discuss (may be you need more experiments to determine exactly the identity of your results)
regards
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Dear all,
considering the transmembrane proteins on exosomes (such as CD9, CD63, and CD81) how do you conduct Western Blot for an optimal detection?
Particularly
- lysis: yes/no
- stripping incubation for serial analyses of membranes: duration and temperature
- re-use of milk+antibody: yes/no (eventually, 4°C / –20°C / –80°C)
- chemiluminescence: best setting?
Thanks!!
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Thanks.
Human urine
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Hello everyone!
I am checking the Reduced GSH form on the HT-22 cell line for, 24hours of seeding (0.5x 10^4 cell/ well) /3hours of treatment, by Promega GSH-GLO kit. Whether it was because of HT-22 proliferation rate is fast GSH sample Luminescence range (149109 - 82356) is out from Standard curve (4736 - 84792). Would you help me with how could I fit my GSH sample fits into the Standard curve? Would it be better to decrease the cell seeding range as 0.25 x 10^4 cell /well, or dilute reaction buffer (1:100)?
Thank you so much!
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Thank you so much for your reply and suggestion!
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What is the meaning of diffuse and specular reflectance in the case of UV VIS when we are recording in the form of powders (glasses)?
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You can check our paper
Synthesis, diffused reflectance and electrical properties of nanocrystalline Fe-doped ZnO via sol–gel calcination technique
Authors
C Aydın, MS Abd El-sadek, Kaibo Zheng, IS Yahia, F Yakuphanoglu
Publication date
2013/6/1
Journal
Optics & Laser Technology
Volume
48
Pages
447-452
Publisher
Elsevier
Description
The nanocrystalline ZnO:Fe semiconductor oxides were successfully synthesized via the sol–gel calcination method. Structural, optical and electrical properties of the investigated samples were characterized by various techniques such as atomic force microscopy (AFM), UV–vis absorption and electrical transport measurements. The optical band gap for undoped ZnO (3.19 eV) decreases (2.75 eV) with increasing Fe-doped ZnO (20%). The temperature dependences of the electrical conductivities of undoped ZnO and Fe-doped ZnO were measured and analyzed by Arrhenius equation. The electrical conductivity of the samples decreases with the increase of Fe doping ratio; hence, the electrical conductivity mechanism is controlled by thermally activated processes. To support the nanostructure of Fe-doped ZnO, AFM micrographs were performed.
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Is it possible to view/record luminescence from luciferase on a standard confocal microscope? Some articles seem to be saying about needing a microscope with a CCD camera, is this the only requirement to view luminescence?
Many thanks,
Jess
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Hi, I also try it by using Zeiss LSM 910. I use the kit from Promega GA5010. I collect emission from 560-615 nm with maximum gain and pinhole. Unluckily I could not detect any signals even though I direct add ATP solution (4 mg/mL) directly into the solution of working solution with adherent cells. Can someone offer me more suggestions? Thank you.
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chemiluminescence plant
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Dear Samir Lazim
I think the following link will be useful for you
Best regards
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Dear Experts, In order to apply carbon dots (CDs) for the removal of analytes, why do we need to encapsulate these nanodots with other materials? Is it possible to use CDs as a lone adsorbent? Thanks in advance for your valuable comments.
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Considering the fluorescence origin, CDs were encapsulated in silica matrices by reacting a silane precursor with surface hydroxy groups that do not contribute to the emission process. It enables CDs in the uniform dispersion in silica to preserve their narrow emission in the solid state by avoiding aggregation.
To enhance the optical properties, stability and to preserve emissions
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Dear all, I have found white precipitate in my transcription buffer which is expired 6 months ago (Promega ribomax sp6 kit). I used the buffer to synthesis mRNA and run a luciferase assay. Unfortunately, I didn't get any luminescence signals.is it because of my transcription buffer or any other issues?
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The precipitate was DTT. Just be patient to dissolve it. If you don't trust the buffer, make your own batch (you can find the buffer composition in the kit's manual). Have you quantified your RNA or visualised it otherwise prior to translation reaction?
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I am using the Tecan Infinite 200 Pro M Plex multimode reader for luminescence assays. Before beginning the assay, I did a test run using just nuclease free water in the 96-well plate. The average luminescence reading I got was 20. I also did a reading with empty wells (absolutely nothing in the wells) and my readings were ranging from 5 to 3805.
My parameters were:
Plate definition: Tecan 96 Flat White (TEC96fw)
Attenuation: None
Integration time: 10000 ms
Settle time: 0 ms
Shouldn't the luminescence for nuclease free water as well as empty wells be zero? Is there a way to calibrate the microplate reader for blank reads?
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Hello.
Are you using absolutely new, sterile plates for your reading? Slightest residue in plates can cause your problem.
I suggest you take a reading of blank plates as control for each experiment. For eg, if you have samples in row A, take the reading of row B as blank and manually subtract B-A to get accurate readings. Or you can also use A before putting the samples as blank and subtract those values from sample values.
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the doped rare-earth(sensitive ion and luminescence ion)under low concentration in host shows abnormal high luminescence efficiency , i suspect that the rare earth ions distribute within linear arrangement to each other. Can i affirm this phenomenon with any simple measuring ways? Thank you
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welcome!
It is so that when the atoms are in the substitutional sites their chemical bond will be defined and this will express itself in free carriers either electrons or holes. Such fee electrons or holes due to doping will increase the electrical conductivity.
Then if your increase the doping and there is no increase in the free carrier concentration this may mean that the added atoms are not chemically active.
Best wishes
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What could explain the loose of luminescence property of a mixed Copper(II)-Europium(III) complexes?
Thank you
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Dear Patrick,
Good question and easy to explain: The Eu3+ PL is quenched by adjacent Cu2+ due to energy transfer, while Cu2+ shows PL in the NIR range, like in CaCuSi4O10 (Egyptian blue) or BaCuSi4O10 (Han blue).
All the best
Thomas
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can we justify the continuous decrease in upconversion luminescence with increasing time of UV/laser irradiation without finding the luminescence lifetime (decay curves)?
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Dear Asif Ali Haider,
I believe that such a process is possible as a result of photodegradation of matter for any luminescent material.
Good luck.
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We use R&D Proteome Profiler Rat Cytokine Array for detection of multiple cytokins in tissue samples. The standard protocol utilizes streptavidin-HRP with a chemiluminescent detection reagent that is not specified in the product documents. Does anyone know, what is the two reagents provided to the kit (chemi reagent 1, chemi reagent 2)?
Have anyone tried another detection system for visualizing (either chemiluminescent or other) the dots?
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We use R&D Proteome Profiler Human Cytokine Array for screening different cytokins. Chemi reagent 1 is hydrogen peroxide and Chemi Reagent 2 is a stabilized luminol.
For your question about using different detection reagents,
Yes, we used Thermo Scientific Pierce ECL and it works perfectly well.
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I am working on the "luminescence properties of Tb ions doped glasses", for which i need the JO analysis of my samples. Therefore i want to know that, what type of software is better for the JO analysis of the Tb ions doped glasses?
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Is it possible? =) What do you think about it?
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Thank you for your interest,
But I would like to tell you the thought in my mind in more detail.
If we simply consider TLDs or OSLDs; The electrons of the dosimeters exposed to the B particles are trapped in the traps and when they are excited with the help of heat or light, they gain energy and get rid of the traps, and we record a luminescence emission.
My opinion is to record the signals obtained from the transitions inside the trap energy levels using microwaves which will cause a movement in the energy levels within the traps because this stimulation energy will be lower energy than the activation energy of the traps.
I am aware that such a study has not been done before and this requires calculations. Just a thought right now.
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The lab I am working in has always done chemiluminescent western blots, but we are looking to start incorporating fluorescence in as well. We have the new fluorescent secondary antibodies, but we want to confirm that the same primary antibodies can be used for both protocols, or if we need to purchase any new ones. Thank you!
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You should be able to use the same primary antibodies, as long as the fluorescent secondary antibodies recognize the species of primary antibodies you are using.
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Hi Expert,
I am facing difficulty to show separate bands for LC3A/B bands. I find only one band. Here are my procedures; I cultivated THP-1 (monocyte, macrophage both tried) cells with 2% FBS Media 24 hours,. I used M-PER and Cocktail Protease inhibitor to make lysate
1. Lysate (20 ug) Load on 4-12% NuPage Bis-Tris gel with MES buffer. Run 100 V, 90 min
(I also tried Bolt 12% gel at the same condition)
2. Transfer to PDVF membrane (0.2 um) at 35V, 2H
3. Blocked 5% Milk with TBST
4. Blotted LC3A/B, Cell Signaling (1:1000), overnight
5. Washed 3x5min
6. Blotted Secondary Ab (1:2000)
7. Washed 3x5min
8. Developed 2 min with SuperSignal™ West Pico PLUS Chemiluminescent Substrate (Thermofisher)
9. I found always one band.
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What is the MW difference between these isoforms?
From my quick search, they seem to both be ~14-16 kDa, and you say your antibody is not specific for one isoform or the other. The only way you'll separate those bands is finding an antibody specific to one(LC3A or LC3B).
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Can you suggest some journals, published article in 1 or 2 months in Luminescence field. Its just a small project work on dosimeter so I want to publish it. Thank You.
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I am doing work on rare-earth doped metal oxide for luminescent, photo detection and optoelectronic devices
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Dear Rajesh,
You can use all RE ions, except those having an empty or completely filled 4f shell, like La3+ or Lu3+. Whether you obtain photoluminescence or photoionisation and subsequently photochemistry depends on the band gap of the host compound and on the energetic position of the excited states of the RE ions relative to the conduction band edge. Therefore, some RE ions show PL in Ln2O3 (Ln = Sc, Y, La, Gd, Lu) and some as e.g. Ce3+ do not.
All the best for your research,
Thomas
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I am finding a suitable research papers using which I could vary thickness to study the UCL and DCL. anyone can guide me about it how I can cover this one. Unfortunately, I am not finding suitable research paper.
NaYF4: Yb, Er / Nd @ SiO2 / TiO2 @ Ag/Au
SiO2 / TiO2 is spacer which I want to vary the thickness.
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Dear Shakeel,
Please specify your question, how you want to study up-conversion or down-conversion luminescence.
Thomas
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I have had this issue for a while now. When I've completed all my probing and am going to develop my Western Blot using the chemiluminescence solutions from Bio-Rad, I find that after about a minute or two post-treatment, right around the time I'm imaging them, the blots develop brown bands where the probe is. This causes issues both with quantifying the bands present and with reprobing, as the stains appear to be permanently adhered to the membrane. In the attached image the bands are starting to become visible, and will continue to darken until they're a solid brown.
I suspect it's an issue with the chemiluminescence solutions. This has happened with multiple membranes, multiple antibodies and antibody concentrations, and multiple blots. Does anyone have any experience with this issue? Is there anything to be done about this?
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I think this results from excessively strong detection, due to a large amount of antigen. So much peroxide is generated locally that it chemically damages the membrane, turning it brown. The solution is to load less of the antigen on the gel, or cut back the concentrations of the antibodies to reduce the detection sensitivity.
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How I can vary the thickness of of Spacer SiO2 / TiO2 in lab ? I am preparaing the UCNPs hexagonal phase-NaYF4: Yb3+, Er3+/Nd3+ @ SiO2 / TiO2 @ Au / Ag. I am not finding sutiable way to vary the spacer thickness. kindly guide , suggest easy and suitable way for completion.
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Dear Dr. Shakeel,
Please contact Prof. Vijay Kumar of NIT Srinagar, India. He is an expert of the same .
He definitely will help you.
Cheers
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What basic information is obtained through the RL signal that is not obtained by using OSL/ TL technique? some literature says, RL helps in identify the presence of impurity but how ???
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Some of the electrons and holes produced by ionization could result in radiative recombination in one of the two ways:
I. instantaneous recombination at the recombination centre after the production and during irradiation to cause a radioluminescence (RL) or scintillation without getting trapped; and
II. recombination via metastable states where some of the charge carriers are trapped and can remain trapped for long periods of time until sufficiently stimulated (TL or OSL).
Since RL is produced continuously during irradiation, information about a radiation dose rate could be obtained in real-time. So, Real-time dosimetry is based on RL.
You can find detailed information from the reference.
Ref; "Pradhan, A. S., Lee, J. I., & Kim, J. L. (2008). Recent developments of optically stimulated luminescence materials and techniques for radiation dosimetry and clinical applications. Journal of medical physics/Association of Medical Physicists of India, 33(3), 85." DOI:10.4103/0971-6203.42748
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Hello,
Is there any relation between the luminescence and optical band gap? I means to say can we explain the change in optical band gap (calculated from tauc plot) by taking cathodoluminescence into consideration.
Need all your suggestion. Kindly tell me.
Thank you
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Hello
In general, there is no direct connection between the Eg and the peak of cathodoluminescence, unless it is assumed that the Eg is almost always larger Elum ... But in principle, exceptions to this rule are also known.
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Mostly the photoluminescence of Yb3+, Tb3+ co-doped materials have low luminescence. Why? and can we enhance the luminescence?
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Thanks, sir Aref Wazwaz but this article discusses mostly Yb, Er. Nothing about Yb, Tb, only at one or two places which is not relevant to my question.
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I have been trying to get the luminescence of my desired cell line which is transfected with luciferase gene and GFP via Varioskan Lux Plate reader. I get a GFP reading but when I use the D-luciferin (1mg/ml in DMSO), working 100ug/ml) on live cells luminescence value is the same as wells which are empty. My queries are:
1. Is it right to dissolve the D-luciferin in DMSO
2. Why there is luminescence in empty wells, is there any way to put it at zero in software or luminescence should is enough high and then subtract the base level lumnisence.
Please suggest the troubleshoot and protocol.
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That's what I thought the case might be. I'd suggest that you try using a strong constitutive promoter with the luciferase as a positive control. Without that it won't be possible to tell if it's the assay that is not working or your promoter is not active.
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In any OSL phosphor we require optical energy more that the thermal trap depth of that trap for optical stimulation. For example in case of Al2O3:C we require 2.6 eV photon to detrap the electron from the trap having 1.12 eV thermal trap depth. How are they related to each other?
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For a given trap, E(optical) is always > E(thermal), because of the Franck-Condon principle. As a result, transitions on a configurational coordinate diagram always take place vertically, meaning that the transition is much faster than the lattice relaxation time. Once ionized optically the defect’s lattice configuration relaxes to a new configurational coordinate via the emission of phonons. Thermal excitation, however, includes the phonon emission and lattice reconfiguration takes place simultaneously. Thus E(optical) = E(thermal) + E(phonons), with the latter term given by the Huang-Rhys factor.
If experimentally measured energies ( for example E(optical) using OSL, E(thermal) using TL) are either unphysically different or approximately the same, I would question whether the two methods are actually probing the same defect, and/or whether or not the E(optical) and E(thermal) values are correctly obtained from the data, before launching into detailed possible explanations.
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Hello,
I want to know is it possible to calculate quantum efficiency (QE) from the cathodoluminescence data. If yes then how?
Thank you
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Dear Smutri,
Thanks for the important technical question, which is not easy to answer. First of all one have to keep in mind that the term quantum efficiency is used in the framework of photoluminescence measurements, whereby the external quantum efficiency (EQE) is the ratio of the number of emitted photons by the number of absorbed photons. Such data are normally obtained by PL measurments in an integrating sphere. The internal quantum efficiency (IQE) can be obtained by time-dependent measurements, i.e. by the determination of the decay time, while the IQE is the ratio of the experimentally determined decay time by the radiative decay time of the luminescent center if there is not any non-radiative quenching process.
However, the efficiency of cathodoluminescence phosphors is not described by the above mentioned figures, but by the power efficiency. This is the optical power divided by the power of the incident electron beam. The best paper w.r.t. these measurements were published by G.W. Ludwig and J.D. Kingsley from GE in Schenectady, NY. Here is the citation:
J. Electrochem. Soc. 117(3) 1970, 348-352
All the best for your research,
Thomas
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Hi all,
for some quick tests I am looking for nanoscopic sources of circularly or elliptically polarized light, ideally single photon sources. I am aware of publications about specially synthesized twisted fluoresence molecules which emit elliptical polarized light after optical pumping (e.g. Kumar, J.; Nakashima, T.; Kawai, T., Circularly Polarized Luminescence in Chiral Molecules and Supramolecular Assemblies. The Journal of Physical Chemistry Letters 2015, 6, 3445-3452.)
In contrast to time-consuming fabrication, are there also circular/elliptical light sources, which are commercially available (e.g. fluorescent organic molecules, colloidal quantum dots, 2Dmaterials, defects in 2Dmaterials)?
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Recently, single photon emitter (or Quantum emitter) is actively researching in many labs, which means intensity of quantum emitter is very weak. That could be why the quantum emitter is not commercially available.
The circular polarized light can be easily formed with a linear-polarizer and a quarter-wave plate.
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I synthesized CdSe and CsPbBr3 QDs in the same amorphous host. Intriguingly, the center emission wavelength of CdSe QDs redshifts through varying excitation wavelengths in the range of 325-425 nm. Excitation wavelength-dependent emission spectra are attached.
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The presence of multiple peaks by changing the excitation wave lengths may be due to the discrete energy nature of the lowest energy levels in the quantum dots.
As the size of the quantum dots get smaller the discrete levels will increase.
Different excitation wavelengths causes only emission from the excited levels which are equal tor smaller than the excitation photon energy.
Best wishes.
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I try to find a book or an extended review article deals with luminescence, scattering, transmission properties of powder mixtures, but I found only a few articles on this subject. Can somebody help me?
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Dear Valery,
By the link https://www.lib.tpu.ru/fulltext/a/2003/31.pdf, you can find the abstract of the dissertation by Vladimirov V. M. The influence of electromagnetic radiation and electron fluxes on the optical properties of powders of white pigments, phosphors, and silicate materials.
There is a dissertation on the photoluminescence of powders by Sergeeva K. A. Synthesis and photoluminescence of low-dimensional willemite doped with manganese https://elar.urfu.ru/bitstream/10995/56218/1/urfu1747_d.pdf.
In the abstract by Yuriev S. A. Optical properties and radiation resistance of titanium dioxide powders modified by nanoparticles of oxide compounds https://www.dissercat.com/content/opticheskie-svoistva-i-radiatsionnaya-stoikost-poroshkov-dioksida-titana-modifitsirovannykh, you can find information about the diffuse reflection and cathodoluminescence spectra.
Similar studies can also be found in:
Оптические свойства и радиационная стойкость порошков диоксида титана, модифицированных нанопорошками различных оксидных соединений https://www.dissercat.com/content/opticheskie-svoistva-i-radiatsionnaya-stoikost-poroshkov-dioksida-titana-modifitsirovannykh
Структура, оптические свойства и радиационная стойкость синтезированных и модифицированных порошков титаната бария https://www.dissercat.com/content/struktura-opticheskie-svoistva-i-radiatsionnaya-stoikost-sintezirovannykh-i-modifitsirovanny
Влияние модифицирования наночастицами на оптические свойства и радиационную стойкость отражающих микропорошков https://www.dissercat.com/content/vliyanie-modifitsirovaniya-nanochastitsami-na-opticheskie-svoistva-i-radiatsionnuyu-stoikost
Структура, свойства и радиационная стойкость оксидных микро- и нанопорошков и отражающих покрытий, изготовленных на их основе https://www.dissercat.com/content/struktura-svoistva-i-radiatsionnaya-stoikost-oksidnykh-mikro-i-nanoporoshkov-i-otrazhayushch
Оптические свойства, структура и радиационная стойкость пигмента оксида цинка, модифицированного нанопорошками
Исследование фото- и радиационной стойкости пигментов, легированных оксидантами и нано порошками https://www.dissercat.com/content/issledovanie-foto-i-radiatsionnoi-stoikosti-pigmentov-legirovannykh-oksidantami-i-nano-poros
Формирование фазового состава, микроструктуры и поверхности функциональных материалов при консолидации нанопорошка диоксида титана https://www.dissercat.com/content/formirovanie-fazovogo-sostava-mikrostruktury-i-poverkhnosti-funktsionalnykh-materialov-pri
Исследование оптических свойств, фото- и радиационной стойкости порошков диоксида циркония и терморегулирующих покрытий изготовленных на их основе https://www.dissercat.com/content/issledovanie-opticheskikh-svoistv-foto-i-radiatsionnoi-stoikosti-poroshkov-dioksida-tsirkoni
Разработка процессов получения и исследование физико-химических свойств наноматериалов для электронной техники на основе оксидов титана и церия https://www.dissercat.com/content/razrabotka-protsessov-polucheniya-i-issledovanie-fiziko-khimicheskikh-svoistv-nanomaterialov
Синтез и исследование наноразмерных частиц диоксида титана для применения в катализе и нанобиотехнологиях
See also the literature on aerosol materials – there you can find information on powders because both are systems with a gas dispersion medium. Similar methods of their production are often used in the preparation of phosphors and laser materials, so in such works, you can find information on optical properties.
Черчес Х.А., Близнюк Н.Н., Скрипко Г.А. и др. Синтез и люминесценция ортованадата иттрия, активированного неодимом и кремнием // Неорг. материалы. – 1985. – Т. 21, № 6. – С. 989-992.
Roy R. Ceramics by the Solution – Sol-Gel Route // Science. – 1987. – V.238. – P.1664-1669.
Segal D.L. Sol-gel processing: routes to oxide ceramics using colloidal dispersions of hydrous oxides and alkoxide intermediates //J.Non-Cryst. Solids. – 1984. – V.63. – P.183-191.
Sheppard L.M. Low-Temperature Synthesis of Ceramics // Adv. Vat. and Process. inc. Metal Progr. – 1986. – V.130, N5. – P.47-51.
Accordingly, the methods of studying such systems can be found in the literature on colloidal chemistry:
Мушкамбаров Н.Н. Физическая и коллоидная химия. – М.: Геотар-мед. 2001. – 380 с.
Зимон А.Д. Коллоидная химия. – М.: Агар. 2001. 320 с.
Гельфман М.И., Ковалевич О.В., Юстратов В.П. Коллоидная химия. – М.: “Лань”, 2003. – 336 с.
Щукин Е.Д., Перцов А.В., Амелина Е.А. Коллоидная химия. – М.: Высш. шк., 1992. – 414 с.
Краткий справочник физико-химических величин / Под ред. А.А. Равделя, А.М. Пономарёвой. – М.: Химия, 1983. – 200 с.
Воюцкий С.С. Курс коллоидной химии. – Л.: Химия. 1984. – 300 с.
Фролов Ю.Г. Курс коллоидной химии. Поверхностные явления и дисперсные системы. – М.: ООО ТИД «Альянс», 2004. – 464 с.
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I have 2 cell lines that I want to use for a drug treatment and my readout would be cell death that I want to quantify using the CellTiter-!Glo kit so it would be luminescence. My only problem is that one of the cell lines expresses RFP very strongly (so much so that the cells and even the lysates are very very pink). Do you think that would cause some issues for the reading in terms of background?
Thank you
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RFP should not create any detectable signal in a luminescence measurement because there is no illumination to excite the fluorophore.
It is possible that the color of the extract could reduce the luminescence measurement by absorbing some of the light. This can be minimized by dilution of the sample or by reducing the path-length of the sample. The light absorption is directly proportional to the concentration of the absorbing material (Beer's Law). In a microplate measurement, the path-length is directly proportional to the sample volume in the well, so reducing the sample volume reduces the light absorption.
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Hello All,
I have recently added a technical history of illumination by incandescent metal oxides to my RG page: I wrote this back in 1994-1995. Has there been any substantive progress and/or agreement towards an understanding how these light sources actually work? Among the incandescent metal oxide light sources I discussed are: limelight, Auer mantle, and the Nernst glower.
Regards,
Tom Cuff
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Fascinating topic 👌. I'm no expert but I do enjoy reading articles on the history of technology from time to time (unfortunately less time for that now, than formerly). Why don't you work some of this up for submission to journals like Technology and Culture or History and Technology?
Cheers.
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Dear Scientists and Scholars,
Luminescent bacteria, (Vibrio harveyi), a gram-negative luminescent bacterium is a major constraint for the successful operation of the black tiger prawn (Penaeus monodon) hatchery.
Does anybody the treatment of this infection during the larval stages in the hatcheries?
Or can anybody please direct me for recent research related to luminescent bacteria?
Thank you in advance.
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Kindly check the following link entitled (CONTROL OF PATHOGENIC VIBRIOS IN SHRIMP AQUACULTURE USING ANTIINFECTIVES FROM MARINE NATURAL PRODUCTS)
As well as this link entitled (POTENCY OF VIBRIO ISOLATES FOR BIOCONTROL OF VIBRIOSIS IN TIGER SHRIMP (PENAEUS MONODON) LARVAE):
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Hi everyones,
I have come to choose one of ultrafast gating and highly sensitive ICCD camera from either Andor istar 340 or PI-Max4 to be used in standoff stimulated Raman detection experiment. Anyone who has experience on using one of those, or both would be of great help.
In my experiment, I am going to excite stimulated Raman emission from some compounds at long distance (>100m) using multiples laser beams (all have 10 ns pulse, 10 Hz rate, wavelength around 532 nm). The backscattered Raman signal will be collected and detectes under ambient light, and the noise will be minimized via fast gating operation, synchronized with the laser. 
I have read that both type of cameras can do the job, but still wonder which one has superior performance?
Thanks inadvance for your help.
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Sorry, not an answer but I noticed this question was from 2017 so was curious if you presumably managed to make a decision on this. Andor also has the iSTAR SCMOS line of cameras which also have short gate times and are heralded to be as sensitive as the PI-MAX4 emICCD (although I am trying to see if anyone has done a comparison).
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Hello, I have been using Chemidoc XRS+ for Western Blotting the last three months (I am new at this), and sometimes I have got a strange issue. After doing all the steps and placing the PVDF membrane into the Chemidoc, the camera does not reveal anything, just as if nothing had been placed inside the device (picture attached). I make use of the next protocol: After electrophoretic separation of my sample proteins, I tranfer them to a PVDF membrane by using Trans-Blot® Turbo™ Transfer System. Then, I block it for 1 hour at room temperature with PBS-Tween 0,5% and incubate it overnight at 4°C with the primary antibody. Next I do is wash 5 times with PBS-Tween 0,05% (10 minutes each time), incubate for 2 hours with the secondary antibody at room temperature, and wash 5 time again with PBS-Tween 0,05%. Finally, I pour the Western Lightning Plus-ECL, Enhanced Chemiluminescence Substrate (PerkinElmer) and, after 3-5 minutes, I drain it and reveal the membrane with the ChemiDoc system. Does anyone know about this? I have been working with this protoco for the last month, and I hadn't had problems until now. Thank you very much.
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Hi Carlos. As I wrote above, I have run into these kinds of problems and I think I have solved them. I highly recommend paying attention to the ECL (replace it with a fresh one) and to the secondary antibody. The latter is particularly critical; in my case the secondary Ab was stored in a buffer containing NaAzide. This Ab began to work only with a few primary antibodies while it stopped working with others. My idea is that perhaps some inhibition of HRP due to NaAzide had occurred over time, thus diminishing the number of active HRP conjugates. This, combined with the number of epitopes on the blot brought by the primary antibody, was enough to affect the signal. In fact, it was enough for me to change only the secondary antibody and the signal returned. Of course I had already replaced the ECL.
Best, Paola
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Li-doped materials such as Ga2O3 show red luminescence which is proposed to result from the Li doping. One such explanation for an emission is the 1s2 3s -> 1s2 8p transition at about 687 nm. See "Accurate Atomic Transition Probabilities for Hydrogen, Helium, and Lithium" for specific details.
My confusion comes from the 3s and 8p levels. Where does the electron in the 3s level come from prior to excitation? Maybe this is a confusion of the notation on my end.
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Hello,
I am growing multiple lentivirus to test the activity of drugs in blocking their entry into cells. The lentiviruses deliver a plasmid encoding luciferase. I would like to compare drug effect between different lentiviruses, pseudotyped with different envelope proteins. What is the best method to normalize the titers of different virus stocks? I have RT-qPCR to determine genome copy number and I have luminescence read-out after infection. While virus genome copy number gives me the number of genomes in the stock, it does not necessarily correlate with infectivity. On the other hand, different virus pseudotypes will have different entry efficiencies, so even with an equal copy number, baseline luminescence will vary. Is it more legitimate to normalize titer based on genome copy number or luminescent read-out? If two viral envelope proteins utilize two totally different cell receptors, can they even be compared in this way? I ask because the number of available receptors may be a limiting variable for certain viruses but not others.
Thank you!
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As you say, you can measure VCN/GQA but that only tells you how many particles you have with packaged RNA. It doesn't tell you if they work, and different envelopes will absolutely vary in how efficient they are at getting onto LV particles and how environmentally resilient they are. Luc readout will tell you how functional the virus is and IMO that's the most relevant metric. After all, you don't care how many particles you make, you care if they work like they're supposed to. Another option is to normalise based on IU/ml - extract the genomic DNA from transduced cells and use PCR to detect integrated virus.
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Please any one can suggest me, that how to calculate the EQE of an OLED from the available data of Luminance (cd/m2) and I-V or J-V curve data of an LED with out using an integrating sphere? I went through few previous conversation, but not clear for me. It will be quite helpful, if any one can help me in this regards.......
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Guo, Haoqing, Qiming Peng, Xian-Kai Chen, Qinying Gu, Shengzhi Dong, Emrys W. Evans, Alexander J. Gillett et al. "High stability and luminescence efficiency in donor–acceptor neutral radicals not following the Aufbau principle." Nature materials 18, no. 9 (2019): 977-984.
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Dear colleagues,
According to the well-known mechanisms of luminescence, the fluorescence has a nanosecond lifetimes, while the phosphorescence has a microsecond lifetimes. Is there any examples of transition metal complexes which displays a triplet emission with nanosecond lifetimes of luminescence?
Thank you in advance.
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There are examples of multinuclear transition metal complexes that show sub-microsecond radiative decay time of T1->S0 phosphorescence due to the enhanced spin-orbit coupling of the emitting triplet state T1 with singlet states.
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I have encountered some studies doing this through some calculations involving FWHM values of PL bands but I couldn't figure that out. I am calculating radii by using the effective mass approximation. EMA predicts radii through bandgap energy, therefore, the output is unrealistically precise and doesn't have any error function. One of the reviewers especially asked for the size distribution calculation from the FWHM value of the PL band.
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There is Scherrer's equation for X-ray diffraction analysis of nanocrystals, which lets calculate average size of them from FWHM of X-ray peak. But I don't listen about similar calculation for PL spectra. Of course, the PL peak position depends on Eg, and Eg is a function of nanocrystal size. So, your calculations of radii by using the effective mass approximation looks quite reasonable, I believe.
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Currently doing research on mechanoluminescence materials, and I plan to create a measurement set-up. The aim is to measure luminescence (wavelength and intensity) properties while the material is compressed by a universal testing machine. Is there anyone who's familiar with this? If so, I might also need recommendations on measurement tools (spectrometer etc.) that I should buy for measurement.
Aside from the wavelength and intensity, is there any properties that is important for mechanoluminescence materials?
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Dear Michaël,
Thank you. The CCD or CMS camera allows you to measure stress images (see attached paper). In my case, when we measured ML spectra we used a Hamamatsu photonic multichannel analyzer. See for instance:
With best wishes
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Hi!
If it is possible to have two luminescence bands of the same peak position in a spectrum, what is the reason behind formation of two separate bands instead of one? This phenomenon is related to the stimulating incident beam or to the nature of the sample?
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With high energy excitation (X-ray, for example) luminescence center (impurity ion) could excited directly through ionization by X-ray and by capture of hole. In addition one can suppose photo-excitation by intrinsic luminescence (of course, if corresponding bands are overlapped). In all cases final step of luminescent relaxation may be the same. Some of excitation ways (especially charge carriers capturing) should be strongly affected by temperature.
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I am facing two main issues while using this assay:
  1. The values for luminescence are super low (0-200) compared to what shown in the protocol (in 2 hours they reach 10,000 or more). I use a wavelength of 485nm for detection, but I also tried several others in the range of 285-585. I treated cells with TNF-alpha but it is probably not good for a positive control.
  2. I saw an increase of luminescence signal from 0 to 6 hours (10 to 280), but a drop of the values after 24h (down to 8 again).
Does anyone have an explanation or can help somehow? That would be very nice!
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Glycyrrhizin might do the trick
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Hello,
As part of my master's thesis, we are gasifying biomass in an entrained flow reactor. We are collecting the light emitted by the flame via a collimating lens and an optical fibre in order to analyse the emission spectrum using a spectrometer. Our aim is to resolve emission peaks in the UV-VIS range as these peaks typically correspond to chemiluminescent emissions of excited radicals such as OH*, CH* or C2*. (See joined spectrum).
I was able to identify some of the transitions as these are quite well referenced in gas flame combustion literature (see table). However, there is close to no literature related to biomass gasification chemiluminescence (which appears to have different emission peaks when compared with typical gas flames).
Therefore, I would like to know if there are any collections referencing a large number of molecular state transitions and their chemiluminescent emission spectra in order for me to identify the remaining peaks. I have been trying to find such collection myself, but have not yet succeded.
Thanks in advance for your help.
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Thank you very much for your answer. The continuum between 320 and 440nm could well be due to a superposition of the CO2* and formaldehyde chemiluminescence, but I haven't yet been able to find a molecule that is referenced to emit the highest peak in this figure (the one at 422.5nm). I've looked through the entire work by Huber and Herzberg "Molecular Spectra and Molecular Structure - Constants of Diatomic molecules". and the only transition that comes close is the BO A-->X transition depicted in the screenshot below.
Considering that we're gasifying biomass and that this peak is present with a high intensity in all our measurements, I highly doubt, that this BO transition is the one is the one we're looking for.
Do you have any ideas, or any hints on where I should be looking?
I haven't found anything in the NIST or the RIOS databases that corresponds and frankly I'm not sure on how to proceed to solve this puzzle.
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At the last step for data analysis, we always use a STOP solution to stop the TMB oxidized by HRP. Why do we have to stop the reaction? Couldn't we measure the color wavelength of chemiluminescence directly? Just like Western Blot data visualization, we just add substrates of HRP to see bands.
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Hello Cheng
We have to use stop solution in ELISA because ELISA technique is different from Western Blot. In ELISA, we have to have OD readings in a linear range. For instance, using standards of different concentrations for plotting a standard curve in order to measure the unknown samples. If stop solution is not used then the signals from the required wells in ELISA will surpass the linear range of amplification and the OD readings will not be proper. As a consequence expected results will not be obtained. The function of the stop solution is to stop the on going reaction somewhere in the middle of the linear phase so that we get proper OD readings and thereby calculate the concentration of the unknown samples.
Thank you.
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Hi all,
I'm doing a bunch of Cell Titre Glo assays to assess the effects of several inhibitors on 2 cell lines. Problem is, for some of the wells they seem to be luminescing less than the background control (media only) wells, some of the time. So I end up with negative normalised values. What would cause this? It's not consistent between replicates or repeats.
Thanks!
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First of all, non-uniform luminescence may be caused by uneven cell seeding, temperature gradient, or edge effect. If you are confident about these conditions, you can check for contamination in your media. It might be the fact that the inhibitor is also killing the microbes along with your cells in the test wells but not in media only cells. Secondly, check the shelf-life of your assay kit to figure out any problem with the kit. All the best.
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The radiocarbon ages (say for the Holocene) is calibrated to Before Present (1950) by using calibration curves and with software such as OXCal. If you use other dating methods such as U series or Luminescence, the age is calculated (Before Sampling Year, lets say 2018). What would be the best way to calibrate these two type of ages, simply add 68 years to 14C age? or calibrate U/Th or Lum ages to 1950?
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Dear Korhan
As you know my new lab includes also 14C dating. I will be glad to help you measure, organise sampling or even callibrate C14 ages, especially versus luminescence ages.
All my best
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I am working on the luminescence properties of Nd3+ ions doped phosphate glasses for which I have to study the decay time. I measured the decay time experimentally and also calculated the decay time through JO theory. Now i want to calculated the quantum efficiency (%) which is given by (measured decay time/calculated decay time)*100.
In my case the measured decay time is greater than the calculated decay time this situation is quit confusing. kindly anybody can suggest a solution or literature having same situations.
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Dear Muhammed,
Very interesating but difficult question. First of all, the internal quantum efficiency IQE is indeed the ratio of tau(sample, measured)/tau(sample, radiative). The question is now, how to obtain the radiative decay time? This can be done by experiments, e.g. to prepare a low-doped (e.g. 0.01% Nd, crystalline!!) sample and to measure the decay time at 4 K to freeze in any non-radiative processes. We did this for YAG:Ce and LuAG:Ce and obtained 65 ns and 54 ns respectively. As an alternative you can use J.O.-Theory, however, from internal Philips reports made on the JO-Theory in the 70ties and 80ties I could withdraw that these calculations are rather inaccurate and not useful to obtain to exact numbers. This might explain your discrepancy.
Also keep in mind, that an amoprhous glass matrix is not well defined and that for this reason the internal quantum efficiency of RE activators is typically low (< 10%). This is the reason, why the big lamp companies never doped the glass, but applied a crystalline phosphor layer on top of the lamp glass (bulb or tube) as a coating.
All the best,
Thomas
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i have got the following photo luminescence spectra data of AU-PD tio2 film for diffrent depotion rates ,can some one help me to analyse it broadly? can we discuss it ??
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I believe that the appropriate thing would be to first find the excitation spectrum, or in your case look in the literature for the excitation wavelength used for this material (if there is anything), the latter also serves as a point of comparison of your results. As for the substrate, it is necessary to see if it presents photoluminescence emission, ideally it would not have to be able to exclusively measure the emission of the material.
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In a Z-pinch test using Pulsotron-3 fusion reactor, I have seen at high-speed camera that a pyrex glass generated a beautiful green light during some milliseconds after the electromagnetic pulse was finished.
The magnetic field was over 300 kilotesla in the target that was several centimeters from the pyrex glass.
It can be seen under "Project log" here:
The pyrex glass was broken but I think there was not a high-temperature raise in the glass. What could generate the luminescence?
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Hola Javier,
Very intereasting observation. From our research on Xe excimer discharge lamps using a quartz or borosilicate glass vessel, we observe sometimes green luminescence, which we have attributed to the loss of Oxygen which goes hand in hand with the breakage of Si-O-Si bonds and thus subsequent Si2+ formation. These low valent Silica species cause defects in the glass structure and the vessel might be destroyed upon long term operation. Possible degraded glass can show luminescence due to either an [Ne]s2-[Ne]sp transition of Si2+ or other colour centers (low valent boron species).
You may find more information on the quartz /glass damage in the following paper, while I assume that pyrex (borosilicate glass) behave similar:
Green luminescence in silica glass: A possible indicator of subsurface fracture
Appl. Phys. Lett. 100, 114103 (2012); https://doi.org/10.1063/1.3693393
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In our lab, we use Corning 3903 White 96 wells plate to culture cells and use Celltiter-Glo (Promega G7570) to test cell viability, I wonder if we could use normal clear 96 wells plate, such as Corning 3599 to do the same test? I know it's better to use white plate to do the luminescent test, but it is also very burdened, thank you!
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Dear Minghui,
We tested this thoroughly and i would not recommend using clear plates. The crosstalk from high values to low values has a strong impact if you have a randomized plate layout, since many low and high values are mixed. Attached you can find an example.
If you have to use clear plates it is crucial, that all high values are together seperated from low values and vice versa otherwise you will get crosstalk between wells.
There are also hybrid plates with white wells and clear bottom which work fine if you wanna have a look on your cells.
Best Regards,
Niklas
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I would be grateful to my colleagues for the transfer of samples for the purpose of comparison with natural samples in terms of luminescent properties.
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