Stocks - Science topic

Hi, I have recently thawed a 3T3-J2 cells from our stock. Initially the cells look like the top image and as I passaged, it became more elongated and "more" fibroblastic/ spindle-like compared to as when it was first thawed. Any one ever experienced this?

During the first passage, I used TrypLe to trypsinise the cells (without washing with PBS) and it took me 15 minutes to detach. I was recommended to used Trypsin/EDTA for the next passage to reduce the time and for that i washed the cells with PBS before i trypsinise as usual.

The recent decision by California to sue the President over executive overreach raises serious constitutional and political complications. The lawsuit is not just a symbolic gesture; it represents growing concern over the erosion of federal balance and the blurring of executive and legislative boundaries.

What makes the situation worse is the apparent disconnect between the administration’s inner circle and the pragmatic realities of how American systems and institutional layers’ function. If anything, this President increasingly behaves like a legislator, obsessed with pushing sweeping laws rather than respecting the limits of executive power. And worse still, those around him seem either unable or unwilling to curb that impulse.

His latest proposal, the “One Big Beautiful Bill Act,” bears an unmistakable resemblance to President Reagan’s 1981 Economic Recovery Tax Act, only amplified in scale and ambition. Historical precedent should serve as a warning. Following similar tax reforms, particularly under the 2017 Tax Cuts and Jobs Act (TCJA), corporations largely used the resulting tax breaks not to drive long-term economic investment or job creation, but to buy back their own stock. In fact, stock repurchases surged from $519.4 billion in 2017[1] to $806 billion in the wake of those policies.[2]

If history is any guide, this new bill is poised to repeat that same pattern: enriching shareholders in the short term while deepening structural economic inequality and increasing federal debt.[3] Meanwhile, Congress, after 25 years of steady decline in oversight and effectiveness, has shown itself increasingly incapable of serving as a meaningful check on executive ambition. Most recently, the House passed the One Big Beautiful Bill Act despite not one, but two clear precedents warning that its core provisions are likely to do more harm than good, especially in terms of cost-benefit outcomes.

California’s lawsuit may mark a critical turning point. As federal institutions continue to weaken in both credibility and function, states—potentially even Republican-led ones—may begin to reassert their autonomy more aggressively. What is emerging is not just a legal battle, but a broader rebalancing of federalism itself. This struggle echoes earlier debates over states' rights, though the motivation today is less ideological than practical: states are reacting to federal dysfunction with self-preservation.

There is a great deal at stake. Whether or not California prevails in court, the mere fact of the lawsuit signals a broader shift. Power in America may be moving, slowly but steadily, back toward the states, redefining the architecture of our federal system in real time.

Bibliography

Economic Policy Institute. “The TCJA Overwhelmingly Benefited the Rich and Corporations While Overlooking Working Families.” Press release, December 17, 2019. Accessed June 8, 2025. https://www.epi.org/press/the-tcja-overwhelmingly-benefited-the-rich-and-corporations-while-overlooking-working-families/.

S&P Dow Jones Indices, “S&P 500 Stock Buybacks: Q4 2017 and Q1 2018 Estimates,” March 21, 2018, accessed June 8, 2025, https://www.spglobal.com/spdji/en/documents/index-news-and-announcements/20180321-sp-500-buybacks-q4-2017.pdf.

S&P Global. “S&P 500 Q4 2018 Buybacks Set 4th Consecutive Quarterly Record at $223 Billion; 2018 Sets Record $806 Billion.” March 25, 2019. Accessed June 8, 2025. https://press.spglobal.com/2019-03-25-S-P-500-Q4-2018-Buybacks-Set-4th-Consecutive-Quarterly-Record-at-223-Billion-2018-Sets-Record-806-Billion.

Tax Policy Center. “How Did the TCJA Affect the Federal Budget Outlook?” Last modified January 2024. Accessed June 8, 2025. https://taxpolicycenter.org/briefing-book/how-did-tcja-affect-federal-budget-outlook.

[1]S&P Dow Jones Indices, “S&P 500 Stock Buybacks: Q4 2017 and Q1 2018 Estimates,” March 21, 2018, accessed June 8, 2025, https://www.spglobal.com/spdji/en/documents/index-news-and-announcements/20180321-sp-500-buybacks-q4-2017.pdf.

[2] S&P Global, “S&P 500 Q4 2018 Buybacks Set 4th Consecutive Quarterly Record at $223 Billion; 2018 Sets Record $806 Billion,” March 25, 2019, accessed June 8, 2025, https://press.spglobal.com/2019-03-25-S-P-500-Q4-2018-Buybacks-Set-4th-Consecutive-Quarterly-Record-at-223-Billion-2018-Sets-Record-806-Billion.

[3] Economic Policy Institute, “The TCJA Overwhelmingly Benefited the Rich and Corporations While Overlooking Working Families,” press release, December 17, 2019, accessed June 8, 2025, https://www.epi.org/press/the-tcja-overwhelmingly-benefited-the-rich-and-corporations-while-overlooking-working-families/; Tax Policy Center, “How Did the TCJA Affect the Federal Budget Outlook?” last modified January 2024, accessed June 8, 2025, https://taxpolicycenter.org/briefing-book/how-did-tcja-affect-federal-budget-outlook.

My DNA stock concentration eventually decrease. I suspect my EB not containg EDTA and I want to make TE buffer. But, i just have Na-EDTA.

Hello everyone, I’m facing an issue where my PCR isn’t working, and I’m trying to troubleshoot whether the problem lies in how I handled the lyophilized primers. Here is the step-by-step protocol I followed:

Is this approach technically sound for routine PCR applications? Are there any risks in storing the primer overnight at 4°C before preparing the working dilution?

GARCH vs ARIMA Explained – Which Time Series Model Should You Use?

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Whether you're into data science, finance, or research, understanding these models is essential for making sound predictions.

💡 Let me know in the comments: Which model have you used more — ARIMA or GARCH?

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Two weeks ago, I run some PCRs, sometimes I cannot get amplification but other times I indeed get it. But now that I am trying to replicate it is not possible, that could not be unspecific bands becase they showed a mutation that I was expecting but no nothind is amplifying. I prepare new stocks of primers, and I have been using everything new. I also isolate new DNA but this is not working, do you have any suggestion?

The sharp drop of stocks that resulted from President Trump's unexpectedly large tariffs sent stocks into a tailspin. The DJIA declined from a December 2024 peak by 16% at the close of trading on April 8. Much of that loss had been recovered by the start of May, however. Is the worst over? Part of the answer lies in whether future bad news has already been discounted. In the case of the 1987 crash, the DJIA fell 36% between

August and October. But the underlying economy was sound, and the averages recovered their loss two years after that crash. In February 2020, the exponential rise in US covid cases caught the U.S. off-guard. The DJIA plunged 28% in a month. By then the lockdown plan had been formulated, and although very costly, at least a policy had been put in place to deal with the crisis. The DJIA fell by -48% between September and mid-November 1929 and began to recover until April. But without a stimulative monetary and fiscal policy, the economy sagged and a banking panic in the fall of 1930 greatly worsened the problem. Ultimately the DJIA would fall 89% by July 1932 falls its Sept 1929 peak. In the case of the 2007-09 recession, concern of subprime mortgages had caused some bumpy DJIA sessions in late July and August 2007, but the market steadied and the DJIA went on to make a high in October. But then Wall Street was rattled again in March when Bear Stearns was about to fail; JP Morgan acquired the company and by Sept 1, the DJIA was only off 21% from its peak. Then on Sept 15, Lehman Brothers failed and the worst financial crisis since the Great Depression occurred in the U.S. By the March bear market trough the DJIA had lost a staggering 54% of its value.

1-How to protect investments from large losses resulting from market volatility.?

2-How enterprises and investors use modern technology to protect their investments from sudden fluctuations in stock prices.

Maximize the following utility function subject to a budget constraint:

U(C) = ∫[0,∞) e^(-ρt) * (C(t)^(1-σ) - 1)/(1-σ) dt

subject to:

dK/dt = rK(t) + wL(t) - C(t)

where:

C(t) = consumption at time t

K(t) = capital stock at time t

L(t) = labor supply at time t

r = interest rate

w = wage rate

ρ = discount rate

σ = risk aversion parameter

I am conducting a turbidimetric assay to determine lysozyme activity, following the protocol provided by Sigma (https://www.sigmaaldrich.com/GB/en/technical-documents/protocol/protein-biology/enzyme-activity-assays/enzymatic-assay-of-lysozyme?srsltid=AfmBOoookbnznAJWFi3oYRM9H4ew6rEAlsOX4yBoFbHizzLO1mp9KTcX#procedure).

I am using lysozyme from Thermo Fisher, which has a specific activity of 20,000 units/mg, and only the substrate from Sigma. The steps I followed are:

According to the protocol, the enzyme activity calculation involves multiplying by the dilution factor (DF). My question is:

Since I prepared 0.02 mg/mL lysozyme and added it directly to the reaction without any additional dilution, my understanding is that the DF should be 1.

However, if I apply the DF of 450 as per the protocol, the calculated activity is an unrealistic 190,000 units/mg. On the other hand, if I assume DF = 1, the calculated activity is 20,100 units/mg, which closely matches the manufacturer’s reported value. Could you clarify how to correctly apply the dilution factor in this case?

In my main research project, I am working with highly concentrated lysozyme solutions (50 mg/mL–100 mg/mL). I would like to determine the enzymatic activity at these concentrations.

Thank you for your help!

I'm running qPCR to study gene expression within two brain regions, the prefrontal cortex (PFC) and nucleus accumbens (NAc) in rats. My goal was to input 10 ng of cDNA per well for each region. For PFC I produced 900ng of cDNA from RNA, with an original concentration of ~42.86 ng/µL of the cDNA sysnthesis reaction, I diluted correctly by taking 3.85 µL of stock into 33 µL total (yielding ~5 ng/µL and thus 10 ng per 2 µL well). However, NAc stock was ~34.29 ng/µL (720ng produced in a 21 ul reaction volume), and the correct dilution should have been ~4.81 µL into 33 µL to achieve the same final concentration. Instead, I mistakenly used 3.85 µL for NAc, which resulted in roughly 4 ng/µL final concentration and about 8 ng per well, which also worked without a problem for a first plate.

Originally I didn't plan to do direct comparisons between the two brain regions. In this case, having a different cDNA input for each region would be acceptable I assume? Since within the regions as long as the cDNA input is the same the relative quantification will work.

But let's say I would like to compare results of both regions:

Is it acceptable to compare gene expression between PFC and NAc if one region was run with 10 ng per well and the other with 8 ng per well, assuming proper normalization with reference genes within each region.

Or would you recommend re-running the NAc plate to match the input of the PFC?

Any insights or experiences with similar situations would be greatly appreciated.

I want to make stock for my drug (2,4-DTBP) which is the best solvent DMSO (for MTT assay )and i want to maintain 0.05% DMSO how can i prepare that stock? and which is best stock concertation for my drug is it (1 mg/mL=1000 µg/mL) or higher ?

I am attempting to prepare a glycerol stock for Stbl3 cells from commercially competent cells for Stbl3. I followed these procedures to prepare the glycerol stock, and I would greatly appreciate it if someone could review and confirm whether my method is correct.

Step 1: Mixed 45 µL of Stbl3 competent cells with 300 µL of LB broth (no antibiotics). Step 2: Shook the mixture for 1 hour at 37°C. Step 3: Plated 200 µL of the mixture on an LB agar plate (without antibiotics, as there is no plasmid to select for). Step 4: Spread the mixture across the plate using a hockey stick. However, after incubation, the plate was fully covered with bacterial growth, with no specific or isolated colonies (as seen in the attached image). I decided to use a sterile loop to pick a single portion of the growth and inoculate it into 5 mL of LB broth (without antibiotics). I placed the culture in the shaker for overnight incubation. then the OD600 is 2.218, then I mixed 500 µL of this bacterial culture with 500 µL of 50% glycerol to create the glycerol stock.

then incubated at room temperature for 20 minutes then stored at -80

Question:

1- Is this procedure correct, or do you suggest plating the 45 µL of Stbl3 cells directly onto an LB agar plate (without recovery in LB broth)?

2- Would it be better to create streaks for single colonies on the plate rather than spreading with a hockey stick?

thank you in advance for your assistance

Hello everyone, I worked around 5years in Domestic Purchase and Inter-company Logistics,

My Idea is making Procurement in smarter way with systematic knowledge directly interconnected with computer softwares Globally like a chain to reduce human interaction like physical counts and monitoring the stocks to reorder the Items with the help of IOT interconnecting all departments in serial and dynamic model to provide information to the managers to make just a decision with received info like order qty xxx -> Existing stock xxx -> Automatic lean Material plan comparing with other items -> Exact needed Qty xxxx to order.

( Incoming Job Order ---> Lean Production Plan with,

--->Incoming RM Stocks Counts & Qty in Store or warehouse and also in unused Vendor & Supplier consignment stock,

---> Lean Production ---> Removed Qty Stock after Production and waste

---> Dispatch & Shipping ---> Transits Logistics ---> Coordination with Supplier and Vendors )

I'm not aware if this technology is already in use. This is just a thought draft, can this be done for Master Thesis?

Please share your advice a view over this.

Thanks in Advance!!

Hi all,

I have all my plasmids stored in glycerol stocks at -80C. I want to split my stocks so I can store them in multiple locations. What would be the best way to do this?

Can I thaw/freeze my stock once or does that damage the cultures too much?

Any other options?

Kind regards,

Kim.

I retrieved a 10-year-old stock of MCF7 (p11), and it has been a week since now, the confluency is like less than 20% but they are still growing, just very slow. Is there a way to determine whether the cells are still viable? Will they reach 70% confluency anytime soon? I am not sure what media was used previously but now I am using EMEM supplemented with insulin. Greatly appreciate if anybody can share their experience with me. Thank you in advance!

I had already tried DMSO 100%, H20 and methanol mixtures(50/50 v/v) to prepare the stock of drug, but still no multiple relationships between 10ug and 100ug these two concentrations on HPLC chromatography . Maybe is the solubility of this drug? But it appears to be completely dissolved.

spectrometer: shimadzu LC-MS/MS 8030 system

Column: purospher star RP-18 (2.1x100mm,2um, merck)

mobile phase: methanol /0.2% acetic acid solution (40/60 v/v)

For recycling purpose

Bacterial with plasmid insert was selected by Ampicilin in glycerol stock and keep it in -80 deep freezer. BUT I streak bacterial from glycerol stock outside lamina flow hood. Do you think there is a chance my glycerol stock will be contaminated? Do I need to recheck it again e.g. check plasmid size, insert size?

We prepared 1, 2, and 3 ppm of copper using the commercial standard for Shimadzu-7800 AA-AAS (Atomic Absorption Spectrophotometer). The same way we prepared 1000 ppm of copper (Copper(II) sulphate pentahydrate) stock by dissolving 0.392 gm Cuso4.5 H2O in 100 ml of water. From this stock, we prepared 1, 2, and 3 ppm of Cu by diluting 100, 200, and 300 microlitres of stock to 100 ml. In AAS we need to enter the weight factor, dilution factor, volume factor, and correction factor to find out the actual concentration of unknown Cu. What should we need to add there? Please give the calculation to calculate the above factors. 

I need to prepare a stock of 10 mg / ml erythromycin to check the mic value. I am trying to dissolve 0.1g/10 ml of water but i can't dissolve erythromycin in water.

How can i prepare 10 mg/ml stock solution? Do i need to use a solvent that does not have an antibacterial effect other than water?

Hello everyone

I have a question that how to resuspend the 20ug of lyophillized esirna or how to make stock. A detailed protocol such as how to make the stocks what should be stock concentration and how do the cakculation from stock to final of 10nM for tranafection in one well of six well.

The researcher is aiming to understand the benefits of effective stock management for businesses, and why is it important for managers and owners to prioritize it .

There is a need to consider organisational and economic mechanisms for attracting investment to rebuild the housing stock, which will be relevant during the period of hostilities.

I got a glycerol bottle but the expiring data is not mentioned on the bottle.

any idea to ensure it is good to use for glycerol stock?

Warner used to sell 8161 glass, but Harvard Biosciences bought Warner and doesn’t appear to stock it anymore

One of the new students I am working with accidentally added jetprime buffer into a stock vial of DNA plasmid I am using to transfect for patch clamp. Will the jet prime buffer affect the plasmid or my experiments and can I continue to use this stock?

are there nursing researches on adverse effects of commodity stock outs on Patient outcomes?

Hello, I am currently establishing a virus infection model in my lab. The cell I use is a vero cell and the virus is porcine epidemic diarrhea virus (PDEV). I plan to use the virus stock without concentration titration to make the new virus stocks, and I will conduct TCID50 analysis of the virus stocks in the future.

First, 0.5 ug/ml to 2 ug/ml TPCK-trypsin test was conducted in 96 well for the condition of virus infection culture (including 0.3% BSA). The virus infection culture was treated after washing twice with plain DMEM using 80-90% vero cells (Figure 1). Then, the appropriate concentrations (0.5 ug/ml, 0.75 ug/ml, 1 ug/ml) were selected and PEDV infection was performed.

Similar to the above process, after washing twice with plain DMEM, the virus stock of unknown concentration was diluted by virus infection culture (by TPCK-trpysin concentration) at 1:10. Finally 5 ml was dispensed into 100 dishes for 1 hour incubation. Next, I washed it twice with plain DMEM, added 10ml of the virus-infected culture medium, and incubated it for 3 days (Figure 2).

What I am curious about is the concentration (0.5 ug/ml or 0.75 ug/ml?) of TPCK-trypsin to establish a virus infection model and the timepoint of harvesting cell supernatant for virus stock manufacturing. What state should the vero cell be in to manufacture the virus stock? Please advise us to establish a virus infection model. Thank you!

Such stocks are typical for Dolly Varden, I know... but what about Arctic char?

I was making a stock of EDTA for my TAE buffer and the pH went to 9.60 instead of 8.0 while adjusting the pH,it is okay to use an EDTA of higher pH as long as it is fully dissolved or does pH 8 specifically serve a purpose? if I should use one at 8.0 pH,is it okay to use HCl to bring down the pH or start from the beginning?

I've been trying to prepare a cell culture media (1% BSA) with palmitic acid (PA), but it keeps precipitating.

I successfully made a stock by dissolving 1 g PA in DMSO, so that's not a problem here. BUT when trying to add the stock into my medium (Both in 37 C), it gets solid! I'm adding 33 ul PA-DMSO in 50 ml medium, so it's not even a particularly high concentration I'm trying to make... I tried vortexing and kept it in +37 C for an hour, but it didn't show any signs of dissolving.

Next, I red some people heating up the medium and PA stock to 70 degrees before mixing, and while that helped (although there are still tiny flakes floating!), I don't think that's any good for the proteins of the medium (e.g. BSA). So, how is this supposed to be done? And is it expected that there will always be some tiny flakes no matter how prepared?

Hello, I have the problem that my nitric oxide standard curve doesn't work. I already used 0.1M as a stock. Does any have protocol of standard curve of nitric oxide by using Griss reagent. Kindly send me.

What can be a hypothesis related to the Stock out Cost or Shortage Cost?

Hi, I need to prepare a standard curve of H2O2 to evaluate the primary products of oxidation. H2O2 I have is 35%. How do I prepare a stock of H2O2 10 microlitere. If s.o has experience, I would be grateful if you share your knowledge.

The absorption should be recorded at 510 nm.

Hi ResearchGate community, how are you? I need to request your help to mitigate the generation of microbubbles detected during the slide preparation of sample metaphase chromosomal spreads. I routinely detect the quality of the stain and integrity of the mitotic chromosomes beforehand with DAPI where consistently no microbubbles have been detected.

However, after my slide preparation with my desired immunofluorescent (IF) stains I finally protect the stained chromosomes with a coverglass, mounting media, and nail polish seal. My lab uses the EMS Shield Mount with anti-fading as its mounting media. I believe this is the source of the microbubbles from a prior inquiry. To mitigate any introduction of air, we store this mounting media in the fridge (per manufacturer's directions) and securely upside down. Whenever I am ready to seal my next slide, I simply push out any initial air bubbles on a paper towel to ensure no air has been trapped when I apply 2 drops to a coverglass and proceed as previously described.

I do recognize that with decreasing volume of the stock mounting media I will have a greater chance for air to be trapped within the stock bottle hence the storage of the stock mounting media bottle upside down. However, my last attempt to seal my metaphase spreads yielded this image (attached) of a microbubble-ridden sample prep. I walk away defeated! Only after applying the mounting media do I see evidence of those microbubbles, they were not present at the DAPI quality check step.

Has anyone else overcome how to completely overcome the introduction of microbubbles in their IF slide preps? I have implemented the prior steps I read on researchgate.net to mitigate such outcomes, but I'm open to any suggestions. We are purchasing a new mounting media bottle, but having this knowledge would help preserve my samples for my next IF slide prep.

Thanks, I appreciate any time and effort you are able to provide to me.

The emerging markets have suffered from a state of stagflation. I hope you know your expectations according to your experiences regarding the implications for the stock markets,,,, risks and returns of stocks.

I am working on antimicrobial effect of CBD (Cannabidiol). As it is insoluble in water, I prepared a stock of 500 mg/ml (in DMSO). Now I have two problems:

1- I can not dissolve more than 500 mg in 1 ml of DMSO (It would become too dense and insoluble)

2-More important, When I pour 100 μl of the stock in the 100 μl of the culture media (Muller Hinton agar) it would shrink and would not dissolve.

My lab doesn't use phage often and recently ran into a problem with too-low of titer for our phi 11 (to the point where I couldn't get it to lyse after 3 and 24 hours). We make a lysate prep, filter sterilize and store in -20. Is there a better way to store this, and/or are we just not using it enough? Should we try to maintain our phage every couple months so we don't run into this problem?

welcome everybody

Can you help me find sources about the relationship between the financial and professional experience of board members and and stock's return? You made a great effort but to no avail?

Most times after checking the cyctotoxity, my results are not consistent. But i used the same concentration of my stock solution. Can anyone help out with how to determine the concentration of my diluted stock solution.

let say:

intial concentration is 20mm and final is 2μM

my question now is, how many μl of stock and medium do i need?

concentrations are 5μM, 2.5μM, 1.25μM, 0.625μM, 0.3125μM

Hello all. I purified some plasmids after doing precultures of strains from a 2-month old plate in -4 degrees. The PCR results were fine and I used theses plasmids to transform Agrobacterium cells. Should I be concerned about physiological changes for these strains from the old plate or even mutations concerning their genetic material ? (PS: I have the strains in glycerol too and I know that spread from glycerol stock should be a best practice).

Hi ,I've woken up my electroporated picha pastoris strain from the glycerol stock at -80°C.from 2020. The literature said that it could be stored for years

I tried to cultivate it, and the strain grows normally in the presence of its antibiotic zeocin.

The problem is that I found no protein expression in the electroporated

vector Pgapz alpha a. There's no troubleshooting in the Invitrogen manual , CAN ANYBODY HELP ME please ?

For H202 radical scavenging assay. How to prepare 75 uM hydrogen peroxide from 30% H2O2 solution ? Thanks in advance.

Please suggest me any paper for this. Is there any process to collect them and find out in lab?

The amount (or stock – t/ha) of soil organic carbon (SOC) by using percentage of organic matter, soil texture is soil depth (cm).

I am grateful for your information.

Hello everyone, I am having trouble with my cell culture. I have used the same cells in the passt, but now every time I thaw a batch (no matter if my own stocks or the original stocks of the lab) the cells are viable for a day or to, but as soon as I passage them the die. However, they don't die directly - they do adhere and start to proliferate, but then the bekom apoptotic. I've checked the medium and every thing else I can think of, and no one else is having trouble with the incubator. Does anyone have any trouble shouting ideas?

Thanks in advance!

I need high frequency data ( per minute , per second ) for apple , amazon , google , microsoft and meta stocks.

I have a master's thesis on the characteristics of the board of directors on return per share, and I do not know how to begin

Dear scientists,

I have encountered a problem where my bacteria (Staphylococcus Epidermidis) grow perfectly fine in liquid media (Tryptic soy broth) but not on agar plates (freshly prepared TSB plates). For the TSB plates that did grow bacteria, often only one small corner grew but not other parts although I streaked all over the plate using a glycerol stock (image1). I also plated the diluted bacteria solution from a liquid culture (OD was about 0.06) on the plates yet nothing grew (image 2). When I used the bacteria that did grow on the plates to streak another agar plate (TSB), they did grow but the middle of the plate didn’t grow anything (image 5). However, when I used a 6 month old LB agar plate for streaking, the bacteria grew perfectly fine (image 3). In addition, I also used an E. Coli liquid culture to streak a TSB plate, and they grew perfectly fine (image 4). I don't understand why my bacteria have problem growing on TSB agar plates but can grow in liquid TSB media. TSB media is recommended by ATCC for the growth of S. Epidermidis. This problem has halted all of my CFU experiments as the bacteria don't grow on agar plates. Would you be able to give me any suggestions why this is happening? Your time and help are strongly appreciated!

I have used Lipton brands in the past for tea bag index (TBI) and rates of organic matter decomposition. I ran out of stock with the brand and want to know if other brands can be used.

I tried to culture the DU145 cell twice from the beginning (stock from the Nitrogen tank).

The first time I tried EMEM + FBS and the second time I tried RPMI.

both efforts ended up not growing.

I tried a mycoplasma test, small flask, and centrifuge at each time splitting, but still they do not grow!

if you have any idea about any of the steps or anything, Please share it with me.

Thank you in advance.

I have 50 ug of Human Her2 / ErbB2 Protein, Tag Free antigen in white powder form and need to make various concentrations of that antigen, such as 50 unit/ml, 10 unit/ml, 0.01 unit/ml, and 0.1 unit/ml. How can I do that? How can I make different antigen concentrations using a 50 ug stock size? What is the calculation for that?

I am having issues in maintaining Xylella fastidiosa. Either they are not growing even within a month or there are some cultures that are growing within 2 days. I have been using HL5F/HL6R primers for confirming the cultures. I am using PD3 media and 30% glycerol for making glycerol stock.

Hi,

Thank you in advance.

I have a glycerol stock of a mutated E. coli (point mutation). I am wondering, if I streak a fresh plate (LB ampicillin) will I have the same clone as original. So that I don't need to send the miniprep plasmid DNA for sequencing?

I prepared a chromium stock solution with a concentration of 1000 ppm. I used chromium metal powder with 99% purity, taking 1 g of the metal powder and dissolving it in 3 mL of HCl. Later, I added 1000 mL of distilled water to prepare the 1000 ppm solution. However, when I checked the initial concentration of chromium in the stock using AAS, the result was still negative. I encountered a similar issue with zinc stock preparation. I would appreciate your explanation for these problems.

Thank you.

1. Take the vial with the cells and thaw it at 30 degrees in a water bath.

2. As soon as the culture is thawed and liquid, remove the vial from the water bath, and clean it using 70% ethanol. Take the 1 ml cell culture from the vial and add it to a 10 ml falcon containing 4 ml of complete Schneiders media (Complete S2 Media: 10% FBS, 1% Pen-Strep, 89% Schnieders Medium). Mix them nicely with pipetting.

3. Place the falcon, now with 5 ml components (1 ml of culture from stock and 4 ml fresh media) in a centrifuge at 100g for 10 min.

4. Remove the supernatant, which would contain DMSO, and then add fresh 5 ml of media (2.5 Fresh S2 Complete Media + 2.5 Conditioned S2 Media) and add this culture to the T-25 flask and let it incubate for 3-5 days before starting passaging.

Am I doing something wrong while I reculture the frozen stock?? Or is it alright and I should just clear out the dead cells using low centrifugation speed for 10 minutes or so?

There are some pieces of equipment that they have in stock and rather enticing prices. I can't find any information regarding customer satisfaction, are they legit, etc. Has anyone dealt with them recently? Did you get what you asked for?

Hello! The freezing protocol for MSCs I have been performing says to freeze 1 ml of cell suspension. I was told that in order to keep confluence, I must add only 1 ml to the pellet of cells and freeze that 1 ml in a criovial. However, my doubt is if instead of freezing in a criovial the 1 ml, I could divide by 3 criovial (around 330µl), increasing the stock of frozen cells.

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Mad Money with Jim Cramer: Episode Recaps, Stock Picks, Lightning Rounds (cnbc.com)

Remote sensing technologies contribute to accurate forest carbon stock estimation and monitoring by providing detailed and continuous data, enabling global coverage, and facilitating the integration of various data sources for a more holistic understanding of forest ecosystems. However, its contribute to accurately estimating and monitoring forest carbon stock at both regional and global scales is lacking.

I want to measure the correlation between deforestation and Carbon Stock in Sundarbans Forest

Q2. How to make stock of monoclonal antibody concentration if it is 1mg/ml?

I hope this message finds you well. I am currently conducting a literature review on the topic of olive carbon sequestration and carbon credits. As part of my research, I am seeking relevant papers or studies that focus on this specific area.

If you have conducted research or are aware of any publications addressing olive carbon stock sequestration and its implications for carbon credits, I would greatly appreciate it if you could share the relevant references or direct me to key resources.

Thank you in advance for your assistance, and I look forward to benefiting from your expertise.

I want to store all records of adding items into racks & remove items from racks in My SQL database to display in dashboard.

I planned to make dashboard which show all racks transaction records with item name, item price, added date, removed date, stock available, stock not available.

Code: Code is in embedded C language.

If I have 200 ml of stock hormone IBA (containing 1.000 μM). How much volume of stock should be pipetted to get 1L medium with 5 µM IBA?

On the website, it says

(Stock solution: 10 mg/ml in water (pH ≤6,0) or 0,01 M sodium acetate (pH 5,2). Do not heat RNase prepared in sodium acetate.)

(Working solution: 2-10 µg/ml in 10 mM Tris (pH 7,5), 15 mM NaCl.)

My real question is which temperature and for how much time should I heat prepare the stock solution( If I mix the powder in water)? while making the working solution from the stock solution in which quantity Ex- how much Tris and how much Nacl should I mix . This is my first time preparing Rnase A. So that is why I am a little bit confused

I am stimulating murine macrophages (RAW 2264.7 cells) with doses of LPS ranging from 0.1 ug/ml to 100 ug/ml (for 24 h) but not seeing any IL-6 production at all (as measured with an ELISA). I ran these experiments back in 2012 and saw tons of IL-6 at all these LPS concentrations (RAW cells treated with all these concentrations of LPS produced over 1000 pg/ml of IL-6). I'm repeating these experiments and not seeing any IL-6 production. I wonder if it has to do with the microcentrifuge tubes I am storing the LPS stock in -20 in (the stock is 2 mg/ml and I make serial dilutions for the treatment concentrations). I vaguely remember using Lo-bind microcentrifuge tubes to store my LPS stock back in 2012, which I am not doing now. But I don't think using normal microcentrifuge tubes would be causing this lack of effect! Sigma is trying to sell me sialized glass vials to store my LPS stock but they are very expensive. Does anyone use these? Can anyone think of why these experiments are not working?

which software is easy and better for 30 stock indices ?

Hi all,

I am trying to figure out the best way to keep a 96-well plate frozen inside an anaerobic chamber. I am currently using a cold plate, sticking it in the -80C freezer, then keeping it all on dry ice until I am ready to take it in the chamber. However, I cannot take dry ice into the chamber, so I bring the 96-well plate on top of the cold plate into the chamber to attempt to keep it frozen. This doesn't work for a very long time before it begins to thaw, so I'm looking for a better solution. Any suggestions?

Has anyone used these? https://ecatalog.corning.com/life-sciences/b2c/US/en/General-Labware/Sample-Cooling-Systems-and-Accessories/CoolBox%E2%84%A2-Ice-free-Cooling/Corning%C2%AE-CoolBox%E2%84%A2-XT-Modules/p/corningCoolBoxXTModules

Hi there!

A simple question to you; i have 10X DTT stock (500mM), and 4X laemmli stock. How much DTT should i add to my sample buffer? DTT should be diluted from 10X to 1X in the Laemmli buffer, or in the final SAMPLE?

So should i just add 100 ul of 10X DTT to 900 uL of 4X laemmli to have 1 ml of 4x final buffer (which will be then diluted with 3 parts of sample) ?

So for example, lets say i have 12 ul of sample, i add 4 ul of 4x laemli/DTT (in which i diluted my DTT to 1x), or should i add 2,8 ul of 4X laemmli plus 1,2 ul of DTT10X ?

Thank you everyone