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Also, can aliquots of microsomal solutions be stored at lower temperatures (-80 degrees) for further use without compromising their activity?
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Thank you very much for your answer Udomsak!
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Hi everyone!
A little backstory: we have these samples of Staphylococcus aureus that are representative of multiple colonies (we call these pooled samples) and we want to test their susceptibility in the Sensititre GPALL3F assay. We are looking to see if these pooled samples have more AMR genes than single colonies picked off the same plate.
To do this, we figured that growing these up in broth rather than picking the 3-5 colonies would represent the diversity more, as it'll give all of the colonies a chance to grow, not just the random 3-5 I would have picked off if following the protocol for these Sensititre plates.
I was told I would have to do a dilution scheme from this broth, and I wasn't sure where to start because I am subpar at math (pls don't judge)!!!!
Basically, my plan so far is to grow up these samples from a frozen stock to a blood agar plate and passage them twice to ensure optimal growth, then put them into 5 mL of TSB broth and allow them to grow overnight. Here is where I'm not sure about the next steps.
To create the 0.5 McFarland standard, how much will I have to dilute my 5mL sample? Should I do a 1:10 or 1:100 dilution of the staph TSB juice and then put that diluted broth into the Sensititre water? Or will I dilute the 5mL TSB by just putting the stock 5mLs into the water and not diluting it in TSB first? Has anyone tried doing a 0.5 McFarland from the broth before, and if you did, how much TSB did you put in to achieve the proper turbidity?
Thank you so much everyone! I hope this makes sense.
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Jessie Gu your strategy is fine, although I suggest doing this slightly differently.
If you want to do an inoculum directly from broth to Sensititre assay, I would avoid TSB, since the presence of cations in the media is important for accurate readings of some antibiotics.
Sensititre has their commercial CAMHB buffered with TES and you can use this same broth for the overnight culture of S. aureus. From that, you can use your broth to make an inoculum in DI water (supplied with the system) until densitometer shows 0.5 MFa and dillute as recommended by the Sensititre in their media.
It is important to use densitometer or at least OD600 nm. to reach the CLSI defined inoculum. Too many or too little bacteria will show different MIC values.
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May I use 2-4Dinitrophenylhydrazine (DNPH) derivatized for formaldehyde 37% solution, Kindly explain anyone how to prepared the stock and standard solution of formaldehyde to use in GC-FID.
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thank u Mr.Baskar sir,
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I am looking for a way to preserve my fungal colonies that grew on PDA already. Something similar to bacterial glycerol stock. I appreciate your help.
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We would put agar plugs in 25% glycerol and stick them in the minus 80. I will say that 25% is not appropriate for all species. I would test a range between 10% and 25% to see what gives the best recovery rates.
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Hi all, I have to do a subcloning experiment and I just have the nt sequence of my insert without any information about the vector (I got the bacterial glycerol stock from another lab that only provided me the nt and aa sequence of the insert). I extracted this DNA and sent it for sequencing asking the company to use a T7 promoter primer. The results were very bad quality, with sequencing peaks overlapping everywhere. Since it could be that there were two plasmids inside, I isolated two single clones from this glycerol stock and sent DNA for sequencing again, obtaining the same bad quality results (and different sequences also). I need to design primers based on this sequence but I don´t trust these sequencing results. What could be wrong with this DNA? Could it be that it´s not a T7 promoter and the primer used binds in a non specific way?
Thanks!
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If you don't have any more information on the plasmid, I would suggest having it completely sequenced rather than trying to do Sanger sequencing. There are several companies that offer cost-effective sequencing using the Oxford Nanopore system.
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Does anyone have any experience with long-term storage/freezing of CFSE-stained bacterial cells and their later use in experiments?
Do you notice any difference in the fluorescence levels from the frozen CFSE-stained stock versus freshly stained bacteria?
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Krystyna Liskiewicz depends on your application and if you need them to be alive or not.
If you need them to be viable, they can be stored in PBS+20% of glycerol in dark eppendorf tubes. If you don't care if they are alive or not, you can just freeze them in PBS or DPBS. If you keep them protected from light, generally there is no decrease in fluorescence.
As a general rule, I would still recommend to prepare them fresh before the experiments since defrosting might affect your assay. But again it depends on what are you trying to do.
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We performed transformation on Saccharomyces cerevisiae, where we introduced a gene mutant library (roughly 14 mil. mutants). Because of the high transformation efficiency, many colonies appeared and created a lawn (the attached picture displays 1 out of 20 transformation plates).
It is very important to be able to calculate the exact transformation efficiency in order to estimate the size of the library.
Does anyone know a way to count the cells despite the 'lawn' formation?
Also, does anyone have any suggestions on how to stock the library?
(could it be as simple as scraping all the cells of the plate and making a glycerol stock?)
Thanks a lot for your help!
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How do you get such high transformation efficiency of Saccharomyces cerevisiae? Can you share your experience?
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I have a project with human neural stem cells but the ones that I was planning to use is from ATCC and currently they are out of stock. Does someone has another company or commercial source to recommend? I am planning to differentiate them in neurons, astrocytes and oligodendrocytes.
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There has been an extraordinary spurt in tech stocks. Though they have the best growth potential, however they also have very high risk to return ratios. From Amazon.com, Inc to Advanced Micro Devices Inc, Broadcom Inc, Uber Technologies, Inc, Visa Inc, Tesla, Inc (USA), TCS, Infosys (India), Weibo Corp (China), Wisetech Global, Atlassian (Australia), they all live up to the reputation as a tech stock. So my question is on finding a suitable metric only to evaluate tech stocks since there are many ways' of evaluating including Price Earnings Ratio, Internal Rate of Return Method, Free Cash Flow Model, Sales Multiple or a combo of these with something else?.
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Hi,
You can also use growth rates for evaluating tech stocks.
Here are some more ideas:
the P/S ratio, beta, net income growth, free cash flow growth, market cap, R&D expense growth and SG&A to revenue.
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I made a 20 micromolar from 10 milimolar stock.
{10000 um × V1 = 20um × 1000 (96 well = 100 well × suppose 10ul in one well drug is consumed)} = This ultimately gives me 2 microliter=V1. 2ul (from 10mM stock) + 98ul Media will give me 20um/100ul. My concern is when I will add this 10ul in 100ul media, which is already added in 96 well plate, so my drug concentration (20um) will dilute and it will changed(X). Please let me know how to calculate the exact volume to get that drug concentration without getting dilute. And I also want to know how to cross check whether in 96 well or any well plate my drug concentration is exact or not??
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As Rohan Ramesh Pawar mentioned, the final volume per well should be 110ul.
So, your calculation will be as follows
10000uM × V1 = 20uM × 110ul
V1= 0.22ul per well. So, it will be 99.78ul media + 0.22ul from stock.
You need to avoid taking small volumes as it can lead to pipetting error.
I would suggest you prepare a bulk working solution as follows.
You need 20uM final concentration of your drug in each well. So, prepare 20uM in a solution for 100 wells i.e., 10ml (100wells x 100ul per well = 10ml).
Use the same above formula
10000uM x V1 = 20uM x 10000ul (10ml)
Therefore V1= 20ul.
So, you will add 20ul of the stock (10mM) in 9980ul (9.980ml) of media.
Then mix this solution well and add 100ul per well. Each well will have 20uM of your drug. I would not recommend adding 100ul per well and then adding the drug. As far as possible avoid frequent pipetting to avoid errors.
I will not be able to answer the second part of your question. I can only mention that you need to be thorough with your calculations while calculating the drug concentrations. Whether your drug concentrations are exact or not will be reflected in the cells’ response to the drug. If you do not obtain a proper dose response which is a cause-effect relationship, then there could be two possibilities
1) Re-check your calculations for drug concentrations.
2) Modify the drug concentrations to get a proper dose response effect.
Best.
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Hello,
I want to create a glycerol stock in a 96-well format so I can directly replicate it into a 96-well plate for growing and future experiments. I expect to do the replications fairly frequently. I'd really appreciate it if people can share what solution works the best for them in a similar situation.
In particular:
- what plate works better: deep well (2 mL) or the normal (~ 200 uL) ones
- do you fully thaw the plate before using or do you scrap from the frozen? If latter, how does resealing work on the cold and potentially wet surface?
- Any other tips to ensure no cross-contamination between the wells?
Thank you in advance!
Nina
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I don't remember. It's been a while that I worked with it.
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Does anyone have experience classification timber harvesting sites based on logging operation and site attributes? I want to categorise timber harvesting sites based on logging operations. This categorisation should be done prior to the logging and site characteristics such as terrain, obstacles, harvest/ stocking, distance to the main road, understory etc. have to be accounted for classifying the difficulty of logging.
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Some models such as Artificial Neural networks and their derivatives.
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Hey,
This may be a odd question, but I am having trouble with the ddRAD Ligation Molarity Calculator Sheet by Peterson et al. (2012) using the BioAnalyzer data.
Can anyone tell me what to enter in the following green shaded cells?
Concentration [pg/µl] (mass/volume concentration from bioanalyzer ("Conc. [pg/ul]")
molarity [pmol/l] (molarity concentration from bioanalyzer ("Molarity [pmol/l]")
annealed adapter conc [pmol/ul] (Final concentration of annealed adapter stock)
What is the difference between the molarity from BioAnalyzer and the Molarity of the Final Concentration?
Everything I read confuses me more and more. I thought it might be the molarity of the stock solution used to make the working solution and the final molarity to be obtained in the ligation mixture? Is this correct?
Thanks a lot to the community.
Cheers,
Julia
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Hey Junjie,
Thanks for your answer but this was not what I was looking for. The units are clear but what value do I enter in these fields when I measure the adapter stocks with BioAnalyzer or another Device?
You have 200 micro mole of oligos.You annealing them to get a 40 micro mole stock solution, you dilute the stock 1:10 to a 4 micro mole solution and from the dilution you wanna prepare the working solution with the sheet of Peterson et al. I measure the 1:10 on the BioAnalyzer and what values do I enter in the cells.
Please correct my procedure, if I am wrong.
Thanks a lot.
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I got transformed E.coli plates and I isolated plasmid successfully from this. But when I laid a new plate from the Glycerol stock (stored in -80 degrees) of colonies from same (previous) plate, I got comparatively smaller colonies and was not able to recover plasmid from that. Can anyone suggest what could be the possible error?
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The Sri Lankan economy is in bad shape.
"Our economy has 'collapsed'" (Sri Lankan PM Ranil Wickremesinghe).
Sri Lanka Holds its Breath as New PM Fights to Save Economy
ttps://thediplomat.com/2022/06/sri-lanka-holds-its-breath-as-new-pm-fights-to-save-economy/
" They say economic mismanagement, policy blunders like a hasty ban on imported chemical fertilizers that devastated crops, and a government stocked with Rajapaksa relatives caused the crisis."
The past experience says that recovery of such economy is difficult and the time / extent of recovery is unpredictable.
What are the ways to bring back a collapsed economy back to track?
(particularly in the context of Sri Lanka)
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Dear Navin Perera,
Excellent presentation made by you. With people like you at the helm of affairs and support from international ecosystem, I am pretty sure that Sri Lanka will be able to overcome this economic crisis. I will go through your presentation in-depth and shall seek more insights on this area.
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I want to cryopreserve ExpiCHO cells (Stocks preparation) so after vial thaw, How many passages I've to do ?
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Cells need to have been passaged at least two times after a vial thaw. Count cells and ensure you have a viable population for freezing. Freeze 10 e7 cells per cryovial.
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If I have a 6x stock and need 3x for my loading buffer. How can this be calculated? and also how much of B-merc to add to the loading buffer.
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For your actual sample you will want 1x working concentration. As your loading buffer will be three times the working concentration you would add 10ul of 3x buffer to your 20ul of sample.
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My lactic acid bacterial cultures that were growing a month or two back isn't growing now. I am unable to subculture it from glycerol stock stored at -20°C. How can i revive it?
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How old is the media you're subculturing it to? Some people in our lab thought our Enterococcus faecalis freezer stocks were going bad but we eventually figured out that E. faecalis stops being able to grow in BHI once it's been left at room temperature for about a month. That stopped happening when we started putting prepared BHI in the refrigerator for long term storage. It might be worth remaking your media if you haven't already - lactic acid bacteria tend to be fussy about their nutrient requirements.
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Component shown in Fig. below is to be manufactured from a C45 steel bar stock of 100 mm
diameter. A batch of 10 such components need to be manufactured using the general purpose machines available in the shop. Mention the machine tool used along with any accessories and
tools needed.
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Figure is missing. Could you provide figure
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Hi, I'm working on a project where we're using S. aureus and corresponding bacteriophages. I did a spot plate and found out that my phage stock is roughly 2.0x10^7 PFU/ml. I want it to be at least 10^10 PFU/ml. My method for growing the bacteriophages has been to make agar plates and then use top agar that's been mixed with the bacteria and the phage dilution. How will I go about making more stock solution that is the appropriate concentration? Do I just have to make it and then test it?
Thank you.
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I agree with Dr. Michael J.Benedik answer
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Hi all, I have several abcam cytokine ELISA kits that came with 2 lyophilized standard vials. I've already reconstituted one vial into stock concentration and I'm wondering if anyone has any experience with how long the stock is stable for. The website and product manuals don't seem to have an answer
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Upon reconstitution, the cytokine standard may be stored at 4°C between 2-7 days, and if it is for long-term future use it should be stored at -20°C. Please avoid repeated freeze-thaw cycles.
Best.
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I have a drug as stock conc. of 2mg/mL with molecular weight of 543.52 g/mol. I need to make 100 ul volume of 4.42 micromolar concentration of this drug. Please guide to make such dilution calculations.
Thanking you in anticipation.
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Hi Aroona,
The solution concentration is 2*10^-3/543.52=3.68*10^-6 mol/ml, then you may use the web tool to calculate https://www.alfa-chemistry.com/solution-dilution-calculator.htm
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I'm having inconsistent results with my checkerboard assay. I'm doing research on antibiotic resistance and the checkerboard shows good inhibition between my antibiotic and inhibitor of the resistance enzyme. However, when I do it on a culture flask (10 ml) total, the bacteria is suddenly showing higher resistance/growth to the combination that worked on the checkerboard assay.
Things to consider: the checkerboard assay is 20 hours long and I often check on the culture flask after 24+ hours. The strain I'm using is E. coli TOP10 and the cloning vector is pUC57. I'm also using LB instead of MHII. Also, when I was using MHII, it was the same thing: bad growth on the checkerboard but good growth in culture flasks. I use the Voyager micropipettes (these things save a ton of time on checkerboards so I recommend investing in one if your lab does a lot of these), so I prepare stock concentrates that are 100x my final concentration. I did a microdilution with both my stock (not the concentrates) and the concentrates and they both showed similar results so I did not make a mistake when I prepared the concentrates.
Can anyone please tell me if they had similar issues and how did you fix it?
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Mu-Shen Chang my school has a shaker incubator for liquid cultures.
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Hi everyone,
A depreciation rate of 15% is widely used for patents’ stock (Hall et al 2005; Blind et al 2021; Lach 1995; Milani and Neumann 2022). What are the corresponding depreciation rates for trademarks’ stock and industrial designs' stock?
In the case of trademarks, I observe either 0% (Sandner and Block 2011) or 15% (Castaldi and Dosso 2020).
Thank you in advance!
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Trademark dynamics are different than patents. Patents expire and therefore it's value depreciates, since the benefit of protection diminishes with time. Trademark expiration reasons are due mostly because there is abandonment or lack of process following. I do find the dynamics of trademarks described in the last two paragraphs in page 2115 of [1] are reasonable to assume.
Hope this helps
[1] Pozdnyakov, Y. V., Zoryana, S., & Tetiana, G. (2020). Price-forming factors choice grounding at intangible assets with negative depreciation independent valuation/appraising. Independent Journal of Management & Production, 11(6), 2112-2139. available at: http://www.paulorodrigues.pro.br/ojs/ijmp/index.php/ijmp/article/download/1170/1482
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I am setting up an RT-PCR experiment for the first time and I am trying to get the calculations for making up my working primers.
This is what I have so far.
Forward primer:
initial concentration: 19.71 nmol
final desired concentration: 775 nMol
Final volume required of diluted oligo: 80 (I'll have 18 wells and requires 4 uL which would be 72 uL primers. I upped it to 20x4= 80)
Calculate:
Volume of oligo stock: 3.145611365 uL
Volume of diluent: 76.85438864 uL
Reverse primer:
initial concentration: 23.72 nmol
final desired concentration: 775 nMol
Final volume required of diluted oligo: 80 (I'll have 18 wells and requires 4 uL which would be 72 uL primers. I upped it to 20x4= 80)
Calculate:
Volume of oligo stock: 2.613827993 uL
Volume of diluent: 77.38617201 uL
I would round the volume of oligo stock and diluent to make it feasible.
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You are making this harder than it needs to be and your math is wrong.
First, your initial primer is being listed as an AMOUNT of molecules (nano moles), not a concentration. You have to add buffer/water/whatever is standard in your lab to go from an amount to a concentration.
Second, you need to make more than the minimal volume of primers to have a chance of accurate measuring. Make somewhere around 500 microliters of the working concentration of each primer and freeze it in aliquots.
Most folks make a stock solution of 100 microMolar concentration of primers and dilute that again into a working concentration, typically somewhere around 2-10 microMolar.
You need to take into account the final volume of your PCR reaction to know if you have added the correct volume of a known concentration of primers. 4 microliters of each primer is not a typical amount, it's WAY too much volume. Most qPCR reactions are around 20 microliters total.
Last, most folks create a "master mix/cocktail" of all common reagents (buffer, enzyme mix, primers, etc.) and aliquot those across the reactions. That way you only have to add in the template.
Talk to folks in your lab. And double-check your math before you start any experiments.
Good luck!
PS Unless this is a first look at your data, 18 reactions is nowhere near enough to include the needed biological replicates, technical replicates, housekeeping vs gene of interest, treatments/tissue types, and standard curve samples.
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Hi there, I'm new to bench science coming from a different background and would love some tips on methods to freeze cells into stocks for storage at -80. My lab uses DMSO for this process. I've tried doing this a few times, but the cells I thaw from stored frozen stocks seem to have a lot of dead cells in suspension and start looking unhealthy after relatively few passages. Are there any tried and true methods/tips to reliably freeze cells so that they are healthy when subsequently thawed? The more detail the better...I'm completely new, so stripped down to the basics and a stepwise explanation would be great. Thank you in advance!
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hi,
The concentration at which cells are frozen may vary between cultures but it is typically in the region of 1 x 106–5 x 106 cells/mL in freezing media; freezing cells at too low or too high of a density can impact viability and should be avoided.
A temperature of less than -130°C is required to completely stabilize cell preparations. This is usually achieved by storage in liquid nitrogen (-196°C), liquid nitrogen vapor, or in an cryogenic freezer (-150°C).
For more info:
Best wishes..
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Hi I would prepare a homebrew stock of ferrite magnetic nanoparticles (MNPs) coated with silica oxide. I`m going to use this stock for gDNA extraction/purification. Do you have any suggestions about which size and which MNPs type, available from various suppliers, is the best for this kind of purpose?
I hope I gave enough information to get an answer
Many thanks in advance
Cheers
Paolo
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From tissue lysate. Many thanks for providing these papers!
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I want to measure the correlation between deforestation and Carbon Stock in Sundarbans Forest
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Replace land survey by airborne Lidar measurements. The forest ministry of Quebec has made huge steps in this direction. - LiDAR - Modèles numériques (terrain, canopée, pente) - Jeu de données - Données Québec (donneesquebec.ca)
- La technologie LiDAR aérien - Ministère des Forêts, de la Faune et des Parcs (gouv.qc.ca)
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I would like to run a Monte Carlo Simulation for stocks. Since stock returns are not normally distributed I am wondering, what is the best distribution function?
What about Weilbull, Frechet, Gumbel, Rossi etc.?
My biggest concern is, to incorporate the difference between median and mean. My Data is:
Mean: 10,67% Median: 14,77 % Standarddeviation: 17,41%
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For highest returns, I would recommend the General Extreme Value distribution. Our analysis in the Turkish Stock Exchange by using this distribution showed, however, that highest returns follow the Frechet distribution.
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Our lab is attempting to grow HAZARA virus and PHV to use in future experiments, however we are unable to proliferate the virus. The procedure we use is to grow the cells to approximately 70-80% confluency, then remove the growth media (DMEM with 10%FBS, NEAA, and Penstrep) wash with PBS, and replace with Opti-Mem (No additives), then add the viral stock (We use 100µl for 1 75ml flask.) and incubate at 37°C for ~90 minutes. Then we remove the Optimem, wash again with PBS before adding Viral growth media (DMEM with 2%FBS, NEAA and Penstrep). We then incubate this flask for several days, taking samples every 2 days. Using rt-qpcr we have not been able to find any significant increase in virus in the media over several weeks. We were able to find virus in the cells once we lysed them, but none in the media.
After a recommendation from another researcher, we moved to testing the media by adding it to wells in a 12-well plate and testing those cells for infection after 3 days, by lysis and qpcr. Even then we have found no infection in any of the media, furthermore the most recent test showed no virus inside the cells even in our positive control well, which was infected with viral stock instead of testing a media.
Clearly, something is wrong with our attempts to infect these cells, but we're not sure what the problem might be, any help or advice would be greatly appreciated.
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You can try other cell lines which may be more suitable for the HAZARA virus, for example, SW13.
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I am looking for programming techniques to use in stock investment recommendation.
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Iuri Velasco The Stock Price Prediction with Machine Learning tool assists you in determining the future worth of a company's stock and other financial assets traded on an exchange. The main point of forecasting stock prices is to make large gains. It is difficult to predict how the stock market will fare.
Machines are not only incapable of anticipating a black swan event, but they are also more likely to trigger one, as traders discovered the hard way during the 2010 flash crash when an algorithmic computer failure sparked a sudden market meltdown. Finally, A.I is bound to fail at stock market forecasting.
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I'm attaching the picture in which there was an Yellow colour layer can be seen in the cryo preserved stock, What is it ?
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hello. In most cases, it's normal. when you store cells immediately in -80 without using foster 40, there are chances that FBS which is in freezing media gets precipitated fast. nothing to worry about. once you thaw, it will be fine and cells will grow. It is not the contamination.
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Please help me out with a link to data on Inward flow/stock of Foreign Direct Investment (FDI) by sectors (e.g., primary, secondary, etc) for individual countries in sub-Saharan Africa (SSA)
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Not a global dataset, but provides sufficient variations for some statistical modelling. Hope this helps!
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I have never had interest in stocks (shares). I need further enlightenment to inform my decision to invest in the stock market.
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A stock is a type of investment in a company. Companies issue stock shares to raise money in order to finance operational needs and to fuel growth, and investors buy those stock shares for the opportunity to generate a return on their investment.
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We are interested in view on whether the different planting patterns in softwood plantations significantly affects form and wood property variation, and studies that examined them. For example if a stand is planted at 1111 sph, does the row x column pattern have any measured effect? Do stands planted on a 3 x 3 spacing differ noticeably and consistently from stands planted at 2 x 4.5?
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In eucalyptus the spacing effect is not very pronounced. It affects some characteristics and not others (chemicals for example). A good study would be to verify what happens with the composition and dimensions of annual growth rings in relation to the initial growth until occupation of the soil with reduction of the volumetric increment.
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Dear community,
What is the code to perform a Fama-MacBeth regression in Stata? I understand how this works theoretically, but I do not understand how this is implemented in Stata. My variables are the 5 factors of the Fama French 5 factor model and 25 portfolios double sorted on size and book-to-market value of equity.
Additionally I have another question as well. That is, in order to test the Fama French 5 factor model, you just regress the factors on one of the portfolios right? In other words, is the correct code to test the 5 factor model:
- tsset date (in order to declare dataset to be time-series data with date as the time variable)
- reg me1bm1 markt smb hml rmw cma (where me1bm1 is the portfolio with lowest marketcap and lowest B/M and the other 5 variables are the 5 factors).
When I use this code I get very strange results, namely that almost all intercepts are significant (which is in contradiction with the Fama French papers). Hence, I am wondering whether there is something wrong with this code. I hope you all could help me with these 2 questions!
Yours truly,
Niek
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Aarthur Schlitz please can you share those satata codes that you have developed to perform FF-3,5
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I have estimated volatility spillover among the stock indices using the BEKK GARCH model in RATS. I want to further calculate hedge ratios and optimal portfolio weights, How do I do this. Can I perform it with the help of any software like E-views, RATS or STATA? Kindly help.
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Dear all,
I am using Stempro-34 medium and with the requirement of 10^(-4) M Ascorbic acid addtion. I have my 0.1 M Ascorbic acid stock in DMSO. The solution was clear at room temperature. However, the moment when I add the appropriate amount of Ascorbic acid stock into the medium, the precipitation appears. There is nothing else added into the medium. Does anyone know how this happens? What can I do to get prevent the precipitation? Or it doesn't affect any active component in the medium, then I just ignore it?
Thanks for your help in advance!
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And precipitate in slow addition of methanol. As you start addition of methanol into water soltion of ascorbic acid, it will start precipitating and take 5th 7 times methanol then water you have added. You will get pets of ascorbic acid.
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Last Night, I thawed old(14 years) HEK293T stock.
But, I failed.
If you have experience in this kind of thing, Tell me your Know-How.
Thank YOU!
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I have quantitated my lentivirus using Takara lentivirus quantification qPCR based kit, wherein comparing Ct values to a standard curve, the copies/ul is coming out to roughly 3.5*10^5 copies/ul. How do I calculate the volume of virus that I require to take from this stock to infect my target cells at a MOI of 5?
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First, you have to decide how many cells you will infect then multiple by 5 to get the number of virus particle you need to use. For example, if you choose to use 1*10^6 cells then you would need 5*10^6 virus particles for an MOI of 5. So the volume of lentivirus stock to use would be 5*10^6/3.5*10^5 = ~14.3ul.
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hello
our lab is doing anaerobic work recently
in our experience
color of resazurin stock is navy blue
and in the anaerobic condition is colorless
and there is a transition step with pink color
in our lab, we use purging N2/CO2 while boiling water combine Na2S method
but we have weird problem
sometimes we make the substrate with light pink color, but after several days it turn to colorless
and sometimes it is colorless but after several days it turn to light pink
so i'm curious what is the redox condition when the color is pink
is anaerobic or not, is there any ORP range can recognize the pink and colorless state ?
Actually we have different kind of pink, is it mean something ?
(our ph value is around 7)
Chao-Jui
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Colorless indicates the media is anaerobic and pink indicates that is was oxidized, and the media is no longer anaerobic.
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I did an ADF test on each stocks of the S&P500 to see which one were stationnary. I did the test using a sample of 30 days by 1 minute interval.
By curiosity I expanded the test to 60 days, and the results changed, I expanded again to 90 days and the results changed again.
For some stocks I took a period where I knew the ADF test would show stationnarity and then added or substracted just one period, this was enough to change the results from stationnary to non-stationnary.
I don't understand why even one period changed everything.
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I still have no experience in preparing WPM medium. I devided mineral salt component into stock 1, stock 2 and stock 3 that are macronutrients, Na2EDTA&FeSO4.7H2O and micronutrients, respectively. In the preparation of stock 1, I tried to separate CaCl2,CaN03.4H2O and MgSO4.7H20, NH4NO3, KH2PO4, KNO3 into 2 solutions which are diluted completely. However, when I mixed 2 solutions together and stired them, then white precipation appeared after 2 minutes. I tried to repeat three times but there is no difference in result. I hope I could be given some experienced advices.
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olha, eu trabalhei com ficcus benjamina varegatano meu estagio e nao tive problemas em relação a precipitação. porem a"sempre a qualidade doa materia prima interfere" me respponde algo, com que especie vc esta trabalhando? esta fazendo indução hormonal?
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Hello, good morning. Our study is about ranking 30 blue chip stocks in the PSE. We want to know the validity of a ranking method called TOPSIS based on the ranking used by the Philippine Stock Exchange which is the VWAP method. I just want to ask if I can use Kendall tau b to know if the ranking given by the TOPSIS method is valid, based on the ranking given by the VWAP method? Because there are ties in the ranking between the two methods. Thank you! I hope you can help me with this.
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You may follow the following study to get some eflections on the uses and criticisms of Kendall's tau:
Lapata, M. (2006). Automatic evaluation of information ordering: Kendall's tau. Computational Linguistics, 32(4), 471-484.
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I would like to learn more about carbon emissions, stock related assessments based on remote sensing techniques. But most of the time for developing countries it is difficult to get above ground biomass information. And it is expensive as well as time-consuming to get in situ measurements. So, what is the best remote sensing solution for this problem?
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I'm inducing M0 macrophages from THP-1 by using Phorbol 12-myristate 13-acetate (PMA)
But frome time to time, I encounter induction failure (twice now), which could be fixed by new PMA stock.
I would like to have some suggestions on storing PMA?
Currently I preserve 5000x and 1000x stock,
5000x stock dissolved in DMSO, and 1000x was diluted from 5000x with PBS.
All stock was store in -20°C.
Is there any suggestions about how many freeze-defreeze cycle PMA could encounter, or if PMA can't left on ice for too long?
Thanks!
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Here are some suggestions.
You make a stock of 5000x in DMSO and then make aliquots of this stock and store in -20 degree C under dark conditions. This stock will last for least 6 months. Make aliquots of this stock in such a way that it could be used only for single use so that repeated freeze-thaw cycles could be avoided.
Do not preserve 1000x diluted stock made in PBS. You will have to make fresh diluted stock in aqueous medium each time you perform your experiment. Such diluted stocks are not stable when prepared and stored.
The diluted stock and the working solution of PMA should be prepared and used on the day of the experiment and could be reused on the same day if you are planning for another experiment on that day. Do not store the diluted stock and working solutions of PMA.
Best Wishes.
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Why do we prepare absorbance of stock dpph at lower than 1?
Thank you for your attention.
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The focus is on variable costs and the value of inventory varies according to the variable cost per unit, and the difference is fixed costs
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I have used Stem Cell kit (EasySep Direct Human Pan-Granulocyte Isolation kit Cat# 19659) to purify PMN/neutrophile from fresh human whole blood (anticoagulant is EDTA, ), the isolated PMN stocked in Falcon 5 ml polypropylene round-bottom tube, about 4 ml cell suspension per tube , store in 4◦C for about 2 hours during the purification work, then spin down at 1200 rpm, 25◦C for 4 min, discard supernatant and resuspend the pellets, pooling all suspension together, I continued to count cells which take about 5 – 7 minutes, from last week and this week, I found the pooled suspension medium become very viscous and glue-like medium during the counting, and I lost more than 90 % of purified PMN, I would like you help me to troubleshot the issue here.
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This website can provide some clarifications regarding your question
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I have NEB 5-alpha Competent E. coli transformed with my plasmid that has a KAN resistance gene. Although the cells are growing very well on the KAN agar plates, they are not growing well in the LB broth. I tried the same stocks of the agar plates and the LB broth with other plasmids and they are growing well. However, with this plasmid, I either get very low growth in the LB broth or almost nothing. So what can be the reason for that?
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I would try picking colonies from the LB - Kan plates into broth LB-Kan broth and also plain LB broth just to be sure it is not some unusual about the broth or the tubes. But I have occasionally seen some clones that don't grow well in liquid broth. It could also be some sort of phage contamination but it would only need to be in those clones and not the other control clones.
And do be sure the colonies seem normal and look like E. coli and grow at a similar rate on plates as your other plasmids.
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Hello,
I have a template pDNA with concentration of 200 ng/uL and I need to add around 4ng in a total of 25 uL of PCR solution. How many uL do I need to add from the stock template DNA?
Do I need to dilute that and then?
Many thanks for your help. I'm going crazy
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Given [initial concentration: 200ng/µl] x [initial volume: x?] = [final concentration: 4ng/µl] x [final volume: 25µl]
So, x=(4 x 25)/200 , x= 0.5µl ==> 0.5 of DNA added to 24.5 supermix or 1µl of DNA to 49µl of supermix recation.
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Could any of you please share a protocol to make Mtb lysates and BCG lysates? I want to make some BCG and Mtb lysates to stimulate mouse splenocytes, Lung and Lymph node cells. So I was looking for a protocol to prepare some lysates to do those stimulations. I have the live bacteria as frozen stocks, of course.
Thanks so much for your kind help.
Best regards,
Gish
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Thank you so much. It is indeed very helpful. Thanks.
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1. I'm gonna fix my cells for cell cycle analysis via flow cytometry method. I've just read a protocol from this link "https://www.abcam.com/protocols/flow-cytometric-analysis-of-cell-cycle-with-propidium-iodide-dna-staining". My question is how long can we keep cell in fixation using 70% ethanol solution?
2. I have 200 mg powder of cisplastin. Does anyone know how to prepare for stock and how to store the stock for long-term using?
Thank you so much!
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Hello Bui Khan
1. You can fix the cells using 70% ethanol for at least 2 hours at 4 degree C. Keeping cells for fixation in 70% ethanol at 4 degree C for 12-24 hours would be still better.
2. Preparing stock of cisplatin.
You can dissolve cisplatin in deionized water up to 2 mM by vertexing it well and letting the solution to remain on the shaker for at least 10 mins at room temperature. Cisplatin is also relatively sensitive to light. Please make a note of this. Do not use DMSO as a solvent because DMSO reacts with cisplatin forming various complexes and so you need to avoid it.
The molecular weight of Cisplatin is 301.1 g/mol
So, you can make a stock of cisplatin by dissolving 0.301 mg cisplatin in 1ml deionized water to get a stock concentration of 1 mM. Make aliquots of the stock solution and store them at 4 degree C in the dark (prevent exposure to light). The stock solution is stable under these conditions for a few months.
You can use this stock solution to prepare the working solutions for your experiments.
Good Luck!
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Hello there!
To the avoid the need of thawing our stock solution we use for our ampicilin stock 50% Ethanol.
Now I thought about making the same with kanamycin. I am worried about the possibility of interaction of kanamycin and Ethanol. I wanted to ask if anybody already uses kanamycin stocks with ethanol or has an idea if this will work out.
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I just tried it and it made the kanamycin drop out of solution instantly :(
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According to EN 12353:2013 microorganisms used in a laboratory must be stored under -70ºC or lyophilized. I'm currently working in a cosmetics laboratory that uses microorganisms such as P. Aureginosa, C. Albicans, etc. in several microbiologic tests. We buy microorganism stocks from a supplier, which arrive lyophilized and need to be stored according to the laboratory practices implemented, however, we don't have a way to store these in temperatures under -20 °C, so is it possible to store microorganisms at this temperature?
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better to maintain the routine subculture process once every 10 days
Make sure to follow the aseptic conditions to avoid contaminations
The stored subculture should be wrapped well using the silicone wrapper or good quality plastic wrapper to avoid cell denaturation
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I want to prepare OADC supplement for mycobacterium smegmatis.
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I am sitting with the same question. what specific catalase is used in the preparation of OADC?
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According to ISO 11930:2019(en) Cosmetics — Microbiology — Evaluation of the antimicrobial protection of a cosmetic product, the process to obtain a work culture is as follows: Attain a stock culture by unfreezing previously cryopreserved microorganisms; From this stock culture perform a subculture and incubate 18 to 24h; From the fist, subculture perform a second subculture and incubate.
The cryopreserved microorganisms are bought and therefore assumed to be pure cultures, so one would assume the sequential cultures aren't to isolate the pretended microorganism. Why according to ISO 11930:2019(en) can we only use the second and third cultures?
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It has nothing to do with the purity of the inoculum but rather with the fact that, after cryopreservation, some bacterial strains may exhibit a prolonged lag phase so with only one subculture can happen that they are not in "perfect" conditions. With a second subculture you make sure the strains are metabolically recovered from the cold temperatures. Hope that helps!
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Hello Everyone,
I am trying to prepare the stocks (50mM) of 4-Nitrophenyl palmitate and 4-Nitrophenyl laurate in chloroform but facing the solubility issues. However, when I tried to dissolve them at higher temperature (45 °C) it is getting dissolved but once it reaches at room temperature, again the precipitation is being observed.
Please, suggest me the way to prepare the above mentioned stocks so that it can be used for lipase activity assay.
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Sorry for the answer because it's not my specialty
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Dilution 1 mg /ml further dilution 1 ml in 9 ml i.e. 10 food dilution, if 0.02 ml of the same stock dissolve in 99.998 ml (total volume 100 ml) what is dilution, how to calculate ?
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For a fairly simple chemical manipulation, your question is quite unclear, is the 1ml in 10ml dilution an example. Also, are you diluting 0.020 ml (20 µl) with 99.98 ml or 0.002 ml (2 µl) with 99.998 ml?
If I understand your question correctly, diluting 0.020 mL (20 µl) of the 1mg/ml stock into 100 ml (final volume) is worked as follows:
1 mg/ml × 0.02 ml ÷ 100 ml = 0.0002 mg/ml.
This is a 100 ÷ 0.02 = 5000-fold dilution.
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Dear Colleagues,
I wonder if any of you could help me by providing a stock of seeds of the Barley cv. Black Hulless? I greatly appreciate your help.
Best regards,
Lóránt Király
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The right plaes to look for good barley collection is the place ofits origin and area around where diversity exits. Please visit Google
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Hi,
I have used the following protocol for HepG2 spheroid immunostaining, however the E-Cadherin staining is very weak and difficult to see.
I am using an Olympus IX70 microscope to image.
  • I am unsure what changes I need to make to the protocol to improve the images?
  • I am also concerned that perhaps the microscope is not powerful enough to provide good images. Also I am open to using alternative primary antibodies - perhap Beta-Catenin.
  • The staining is undertaken in a wellplate at the moment. I cannot fix to slides as I am trying to adapt for microfluidics.
Any suggestions to improving images welcome
Immunostaining of HepG2 spheroids - Protocol
1. Samples fixed with 4% (v/v) paraformaldehyde (PFA) for 1 hr @ 37C, washed with PBS and then permeabilized for 1 hr with 0.3% (v/v) triton permeation solution @ RT with gentle agitation. Washed with PBS
a. Triton – take 3uL in 997uL to give you 0.3%
2. Sample blocked for 2 hrs with blocking buffer (10% BSA in PBS). Incubated overnight @ 4°C in PBS with 1.5% BSA containing primary antibodies at a suitable dilution e.g 1:500 & 1:1000.
a. 250ug/mL Anti-E-Cadherin –
a. 1uL from stock into 999uL PBS to give 0.25µg/mL
b. 10uL from stock into 990uL PBS to give 2.5µg/mL
c. 20uL from stock into 980uL PBS to give 5µg/mL
Takes 4 hrs + overnight to this step
3. The samples were washed with DPBS and incubated for 2 h with secondary antibodies @ RT in the dark at a dilution of 1:500
a. 1mg/ml Alexa-flour – 10uL of stock into 990uL in PBS to give 10ug/mL
4. The samples were then treated with DAPI (1:1000) for 15 min at 37 °C and washed briefly with DPBS before imaging.
a. DAPI 1 mg/mL – 1ul of stock into 999uL in PBS to give 1ug/mL. Prep immediately prior to use.
Takes 2 hrs 15 min + overnight to this step
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Dear Saurabh,
Please also look at the following protocol:
Histological and immunohistochemical analysis. HepG2 cell spheroid suspension was collected in PBS and spun at 1,000 rpm for 5 min. The pellet was fixed in 10 % buffered formalin and embedded in paraffin. Tissue sections (3 μm) were prepared and stained with hematoxylin and eosin, PAS (Periodic acid-Schiff’s reaction) and PAS after treatment with diastase to remove glycogen. Human liver tissue was provided by Bronovo Hospital, The Netherlands, in accordance with the hospital’s code of conduct regarding use of patient-derived material. Immunohistochemical detection of cytokeratin 7 and 8 (CAM5.2, 1:20, BD Biosciences, Ref. 345779) and bile canaliculi (polyclonal CEA, 1:200, DAKO, Ref. A0115) was performed using an automated immunostainer (Benchmark ULTRA, Roche Diagnostics).
Histological analysis
Spheroids were washed in PBS, fixed for 1 hour in 4% PFA and embedded in 2% Agarose (low EEO-Sigma Aldrich) in 4% PFA then paraffin embedded. Tissue sections were cut and stained with haematoxylin and eosin (H&E) or as previously described.39 Immunohistochemistry for Ki-67, carbamoyl-phosphate synthase 1 (CPS1) and CYP2E1 was carried out by the Department of Veterinary Pathology, Leahurst Campus, University of Liverpool, UK.
Immunofluorescence analysis of spheroids
Spheroids were transferred to ULA plates, washed three times in PBS and fixed with 4% PFA for 1 hour at 4 °C. Spheroids were washed again then permeabilized with 0.5% Triton X-100 in Tris-Buffered Saline with 0.05% Tween20 (TBST) overnight at 4 °C and then blocked with 0.1% Triton X-100/3% BSA in TBST for 2 hours at room temperature (RT). Primary antibodies Multidrug resistance protein-2 (MRP2-Abcam) and P-glycoprotein (Pgp-Abcam) were diluted 1:20 in 0.1% Triton X-100/1% BSA in TBST were incubated with the spheroids overnight at 4 °C. Spheroids underwent three 1 hour washes with 1% Triton X-100 in TBST then incubated with secondary Alexa Fluor 488 Donkey Anti-Mouse antibody (Life Technologies) diluted 11000, Hoechst diluted 1:5000 and Phalloidin 568 diluted 1:250 in 0.1% Triton X-100/1% BSA in TBST overnight at 4 °C. Spheroids were finally washed for 1 hour then mounted with Prolong Gold (Life Technologies) onto a glass microscope slide. Maximum intensity projection images of spheroids were taken using a Zeiss Axio Observer microscope with Apoptome using 40× oil objective.
Culture Medium
HepG2,
Immunostaining of Spheroids
The merged spheroids were fixed by paraformaldehyde (PFA, 4%) after collecting and washing with PBS (1X). Then the spheroids were permeabilized by Triton X-100 (0.5%) at room temperature for 30 min. After washing with PBS three times, the spheroids were immersed in BSA (1%) blocking solution for 2 h at room temperature. The solution was then replaced with anti-E cadherin antibody (1/500) and kept at 4 °C overnight. The excess antibodies were washed away with PBS. The Alexa Fluor 488 labeled secondary antibodies (goat anti-rabbit IgG, 1/800) was introduced at room temperature for another 1 h. The spheroids were then washed with PBS and immersed in the solution of DAPI (10 µg mL−1) for 30 min. After totally washed with PBS, the spheroids were placed in an ibidi chamber (200 µL PBS) and imaged by confocal microscopy (LSM 800, Zeiss Germany). The spheroids were settled by natural sedimentation method in each step in order to keep the original shape of the spheroids.
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I have 100 mg of 3-MA (autophagy inhibitor) powder.
I'm gonna add 1.342 mL of pre-warmed sterile water to make 0.5 M stock.
Can I do that? Will it be precipitated at that high concentration?
If not, please suggest me another solution.
Thanks for your interest in my question!
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3-Methyladenine blocks autophagy through its effect on class III phosphatidylinositol 3-kinase (PI3K).
Please see the reference given below:
The 3-MA has been reported to inhibit autophagy at concentrations ranging from 1-10 mM was directly dissolved into the culture medium at the indicated concentrations. The solubility of 3-MA in DMEM is 31 mg/mL at about 40°C.
The 3-MA is dissolved in DMSO (warmed with 50ºC water bath) 10 mg/mL (67.05 mM), while in water (warmed with 50ºC water bath) 4 mg/mL (26.82 mM).
The choice is yours
Best
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I want to know how I would prep 500ml of 25% weight/volume potassium hydroxide. From this stock, how would I perpare a 0.1M working solution?
If you could give as much detail on working out too please. I'd like to understand.
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A 25% (w/v) solution means 25g of solute in each 100ml.
Preparing 500 ml of 25% (w/v) KOH requires 25*5= 125 g of KOH (five times the amount to make 100 ml. This weight has to be dissolved in about 500 ml of water. That could be done by first solving it in about 400 ml of water and then diluted to get a final volume of 500ml. (Take also in consideration the purity of the reagent... For ex: If your reagent is 95% pure you will need 125/0.95= 131.59g of KOH 95% purity.). Then you will have your stock solution.
Now for the working solution:
A solution of 0.1 M KOH contains 0.1 mol KOH each 1000ml.
Molecular weight of KOH is 56.1 g.
So, 0.1 M KOH contains 5.61 g NaOH each 1000ml.
To get 1000ml of KOH 0.1 M you need to take 22,44 ml of stock solution... as:
0.1 M KOH * (56.1 g KOH / 1 mol) * (1000 ml KOH 25% / 250 g KOH) = 22,44 ml KOH 25%
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The Fed plans to trim its balance sheets and has warned investors that rate hikes are coming later this year. As interest rates rise, general stock and bond prices fall. P/E ratios for the various US stock indexes are relatively high by historical performance, earnings in some critical sectors have been disappointing. And, over the past week, stocks have dropped sharply. Early morning rallies have ended in sharp share selloffs at the closing bell.
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A significant correction is coming. The correctiom may be worse than the crisis in 2008. First, we must see droves of people unable to pay their monthly mortgages. But I can feel it coming. What is your call?
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Dear All,
I’m conducting an event study for the yearly inclusion and exclusion of some stocks (from different industry sectors) in an index.
I need to calculate the abnormal return per each stock upon inclusion or exclusion from the index.
I have some questions:
1- How to decide upon the length of backward time to consider for the “Estimation Window” and how to justify ?
2- Stock return is calculated by:
(price today – price yesterday)/(price yesterday)
OR
LN(price today/price yesterday)?
I see both ways are used, although they give different results.
Can any of them be used to calculate CAR?
3- When calculating the Abnormal return as the difference between stock return and a Benchmark Return (market return), The market (benchmark) return should be the index itself (on which stock are included or excluded) ? Or the sector index related to the stock?
Appreciate your advice with justification.
Many thanks in advance.
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Hi there, I am using Eventus software and I am wondering how the software computes the Market index in order to calculate abnormal returns?
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Hello,
I'm having a trouble with HaCat culturing from stock (the medium for stock with the ratio 9 full DMEM : 3 FBS : 1 DMSO). The cells seem to secret many black dots as shown in the picture and their morphology are abnormal, too. I tried to subculture over several passage and wash carefully but the black dots still appear. Does anyone have the same trouble like me? Please give me some advices. Thank you!
P/s: I also wonder if the black dots are mycoplasma, however they do not move and seed to the plates.
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Hi everybody,
I also had the same observation with haCAT cells and trying to figureout the reason whya nd how to fix it.
Amal.
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I am following a potocol from this paper :
They suggest to mix the stock in 3 different dilutions (1:1, 1:4 and 4:1) but no more details. Now I am getting confused with what they mean by 1:4? When we prepare 1:10 we use 10+90, right? so 1:4 means 10+30. isn't it? My confusion is, when we say 1:4, it could mean 1 out of 4 which means 10+30, but we can also say, 4 times of 1 which means 40+10. I would really appreciate your expert opinion.
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From wikipedia:
In chemistry and biology, the dilution ratio is the ratio of solute to solvent. It is often used for simple dilutions, one in which a unit volume of a liquid material of interest is combined with an appropriate volume of a solvent liquid to achieve the desired concentration. The diluted material must be thoroughly mixed to achieve the true dilution. For example, in a 1:5 dilution, with a 1:5 dilution ratio, entails combining 1 unit volume of solute (the material to be diluted) with 5 unit volumes of the solvent to give 6 total units of total volume.
This is often confused with "dilution factor" which is an expression which describes the ratio of the aliquot volume to the final volume. Dilution factor is a notation often used in commercial assays. For example, in a 1:5 dilution, with a 1:5 dilution factor, entails combining 1 unit volume of solute (the material to be diluted) with (approximately) 4 unit volumes of the solvent to give 5 units of total volume. Note that some solutions and mixtures take up slightly less volume than their components.
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hi everyone,
Where can i get free access for real-time historical stock data, or intra-day stock data, which is stock data with every second transaction .
Thank you.
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Dear Rosita Husain,
Greetings!
You can check the following links
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For a project at University i need to estimate the carbon stock of individual Acer trees. I can't seem to find proper equations to do this. thanks in advance for your tips!
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Kindly visit..
Comparison of Allometric Equation and Destructive Measurement of ...
by SH Han ·
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How can I store my bacterial isolates for long-term (not glycerol stock) to use culture directly instead of subculturing the bacterial petri plates after every 4-5 days?
Like it should be easy to take the bacterial colonies directly for other tests as we do with the petri plates.
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اسف الموضوع ليس من صميم تخصصي
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I'm currently doing my undergraduate essay about American stock option implied volatility. Our school do not have the access to OptionMetrics. So I find the data in Nasdaq but couldn't subscribe since I can't apply for a credit card in China.
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Sorry, I don't have a subscription
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Hello, it's my first time to transfect High Five (Hi5) cell lines and I'm having hard time solving the problem: The expression level was quite low but background was too high.
Previously I followed my coworker's protocol:
1. Transfect Sf9 maintained in Grace's media with 10% FBS using pBacPAK8 baculovirus first
2. Get virus stock
3. Infect Hi5 cell maintained in serum free media
She told me that she used this protocol because Hi5 cells should be maintained in serum free media. But actually, she has gotten low expression level too. So we're wondering if there's more efficient protocol to enhance the expression level using High Five cells. I've searched for protocols, but I couldn't find any detailed ones.
Can't I just adjust and maintain High Five cells in Grace's media with 10% FBS and directly transfect them? Or is there any method using cell lines maintained in serum free media to transfection?
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The insect (Hi5) cellsTm cell line development by using site_ specfiv Flipase recombination technology according to attached ref.: https:// pub.med.neb.nih.gov>
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I dissolved indomethacin (Santa Cruz Biotech - SC-200503) in DMSO and prepared stock of 25 mg/mL
In my study, I inject 10 mg/kg i.p., injection volume 0,5 mL and I work with 250-300 g rats.
When I diluated the stock solution with saline (%0,9 NaCl), the diluated solution has been crystallized.
How can I avoid that?
Open for any suggestions.
My kind regards.
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What makes biotech stocks spike? will it be a good case, if you are trying to create a big company and sell its shares on stocks markets1?
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I want to check herd behavior in value stocks and growth stocks companies. I have bse 500 companies and book to market ratio data of these companies.
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I agree with Ako Doffou about Growth stocks
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I' m gonna use it as an indicator for biofilm formation of specific bacteria
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Prepare a 12 mM stock solution by dissolving 5 mg of MTT [3-(4,5dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] in 1 mL of PBS. This stock solution will be enough for 100 reactions (10 µL per reaction). Once prepared, the MTT solution can be stored for 4 wk at 4°C protected from light.
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Hello,
I'm looking at HtrA protease activity and don't have any Brij 35 in stock. Is there something else I can use instead of this detergent?
Thanks for the response.
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Brij-35 is an industrial polyoxyethylene detergent, that is, purity and length of the ethylene oxyde chain are poorly defined. It is used as a cheap replacement for C12E23. Like all detergents of this class it can form ether peroxydes, which can inactivate proteins. Although removal of peroxydes is possible, it is laborious and involves nasty solvents. Better to buy peroxyde-free qualities to begin with, which are supplied under inert gas. Store in a cold, dark place protected from air.