Reference Standards - Science topic

No, you shouldn't use those exact dimensions from the article. They actually don't comply with ASTM C393 requirements.

The article used:

For proper ASTM C393 testing, you should:

If lab constraints make this difficult, consider reducing your sample thickness to maintain proper ratios. For example, with 6 mm thickness, you'd need only 120 mm span while maintaining ASTM compliance.

Hope this helps your research!

S U M Rao Rafia Rahman

Great attempt!

The key components of Q1 are:

1. Accreditation Boards:

- Accreditation Board for Testing and Calibration Laboratories

- Accreditation Board for Certification Bodies

- Accreditation Board for Hospitals and Healthcare Providers

- Accreditation Board for Education and Training

2. Board for Quality Promotion

- This board is responsible for promoting and propagating quality standards in different spheres of activities.

3. Bureau of Standards

- Responsible for formulating standards and certification under the ISO structure.

4. Metrology System

- Operates under the CGPM (Conférence Générale des Poids et Mesures) and CIPM (Comité International des Poids et Mesures) structure.

5. Legal Metrology

- Operates under the OIML (Organisation Internationale de Métrologie Légale) structure.

The key functions of Q1 are:

1. Establishing and maintaining a robust quality infrastructure at the national level.

2. Accrediting and monitoring testing and calibration laboratories, certification bodies, hospitals, healthcare providers, and educational institutions to ensure adherence to quality standards.

3. Promoting quality awareness and adoption across various sectors.

4. Developing and maintaining national standards in line with international standards.

5. Ensuring the reliability and traceability of measurements through the metrology system and legal metrology.

Overall, Q1 plays a pivotal role in improving the quality of products, services, and processes, thereby enhancing the overall quality of life and well-being of citizens.

Thanks; partial credit AI

No. "MS" data is only as good as the overall method used to collect and evaluate it (The "method" includes the column, mobile phase, instrument settings, standards and proof that the method follows good chromatography fundamentals). With no standards for comparison and other orthogonal techniques used, no identification would be possible. Purely speculative.

MS data on its own has very little value as a MS system will always output "data". Data "from other studies" would be anecdotal at best as only data collected on the same instrument, by a trained operator (which takes many, many years) using standards with an approved method would be useful to draw conclusions from.

Good day, R S Krishna! Hope you are doing well.

Hope, following links will share some new insights with you:

Feel free to mention me in your response in case of any extra questions.

Best of luck in your research!

Yours sincerely,

M. Sc. Vadym Chibrikov

Department of Microstructure and Mechanics of Biomaterials

Institute of Agrophysics, Polish Academy of Sciences

I do not know the cause of this, but it could have similar causes to the disappearance of search results in Google and Google Books. I have repeatedly found that search results I had noted down could no longer be reproduced in a later search, although the corresponding books still exist, of course. Search results also often depend on a combination of certain search words - one combination gives a correct result, another does not, although all combinations are contained in a book or a web page. I suspect that these are shortcomings of Google's indexing algorithms. It may be that your citation still exists in Google's database but is not displayed as a result of a new indexing. Perhaps it will reappear in a few weeks after a new indexing.

Thanks!

Check herein

Please, cosider, also the following attachments, associated with reference [1], shown in my preceding posting:

(i) MTZ-urine-equ.tiff: It contains our innovative basic equations (1) and (2);

equation (3) is according to Arrhenius's theory;

and

(ii) MTZ-urine-dqc.tiff: It contains diffusion coefficients of MTZ in urine according to reference [1] and equations (2) and (3). As can be seen, there is excellent correlation between our theory and Arrenius's one.

Once, when there are assigned MS ions to corresponding 3D molecular structures, there is not needed employment in internal standard.

There is, in actual fact, excellent-to-exact liner correlation between two completely independent theories: Our stochastic dynamic formulas, mentioned above, and the Arrhenius's one.

Thus, 172.072 belongs to N³⁺-cation of MTZ, while MS peak at m/z 172.041 is assigned to N⁺O-cation. MS peak at m/z 171 belongs to cation-radical of MTZ.

The shown equations describe completely and absolutely mass spectrometric phenomena toward (a) quantitative and (b) 3D structural analyses of analytes.

In other words, even in complex matrix like urine, there is completely able not only to determine analyte quantitatively, but also to determine its 3D molecular structure; furthermore, exactly in chemometric terms.

Quality Management in Industries ( ISO ) - https://www.googleadservices.com/pagead/aclk?sa=L&ai=DChcSEwjJxrf035nxAhVKBCsKHUbCBSAYABAAGgJzZg&ae=2&ohost=www.google.com&cid=CAESQeD2bkvWs1tzq2MX4R_lIfKMOrMuEcZqaO7z0j4okR55VQjdipFtkGt_O19WG2apF0q6fM8aVHKWDLSItOmM8-Tm&sig=AOD64_0dgWFMIa89-C_69kSmupB6csjbJg&q&nis=1&adurl&ved=2ahUKEwjZrq3035nxAhWDwTgGHTskDYAQ0Qx6BAgCEAE

Dear Hassan El-Abid I just found another potentially useful link entitled

It contains a section about the ban of lead in paints.

Exactly you have to do dilution for your sample and multiple by dilution factor

Also check https://www.sigmaaldrich.com/analytical-chromatography/analytical-standards/lipids-fatty-acids-standards.html

The problem could sit in the stability of the pre-coated ELISA plate and in the standard solutions themselves. Dried blocked plates usually keep well upon storage, at least for short time in the fridge. For long term storage, companies have more or less well kept secrets as additives.

For high dilutions of standards, you'll observe adsprption to the walls of the containers you are using for storage. To prevent this, in the case of proteins, use carrier proteins like BSA to compete for adsorption space, with small molecules it might help to add similar molecules that won't interfere with the test. Sometimes using 0.5% Tween (or the same buffer that you'll be using for the ELISA, usually TBST) or similar, as excipient will do the trick.

Dear RG colleagues,

I always see another type of here at this respective portal. Please look at the answer that is directly before my answer which is written by "Deleted profile".

"Informality in Metagovernance"! So that's what it's called. This is so intriguing, Remi. Thanks!

Dear Robert Möckel and Gerhard Martens , thanks a lot for your help. It turned out to be tube tails and Kb absorption edge artifacts. The such prominent tube tails are not usual indeed. I found out later that the tube is degrading very quickly. It is only 3 years old, has only 2 years of heavy use and now produces only 10% of X-rays in comparison to three years ago state. Apparently, there is a major defect from the factory. May be this causes such strong tube tails as well.

Please look at ASME B31.3 Code Table A1 for minimum design temperature of materials. But Low temperature carbon steel ASTM A350 LF2 is very common forging carbon steel rather than A105.

, you are welcome. Do report bugs to me if you find any.

You can find it in the following paper:

In Germany, standards of the International Standard Organization can be viewed (but not copied!) free of charge in the offices of the German Standards Organization (DIN). These offices are located in all major German cities. Since the Philippine Bureau of Product Standards within the Department of Trade and Industry is a member of ISO , this possibility could also exist for you in Manila. You should check this out.

I think you will have a problem with fitting curve and quantification of results after.

in addition to playing around the mobile phase; In my opinion try to see the property of the compound that gives you two peak.develop MRM for the compound and see in at which RT your compound papers (should be one) and try to remove the source of adduct and play on the MS collision energy (capillary energy)

To Tony Maine. Yes, I think if one designs a new motor that is dedicated to be supplied exclusively by frequency converters (FC) it is a right decision. However, the majority of motors that used with FC are still either usual DOL induction motors or motors that are dedicated both for grid supply and fot converter supply. They have the rated voltage about 400 V. So, I want to calculate correctly the maximum available voltage in the case of using the DOL motors with FCs, in order to make calculation of energy consumption and other performances of variable speed electric drives with a higher accuray.

Following

Hi Antonio .. I understand that one need to prepare multiple standards with varying concentration between 0.005 ppm to 0.015 ppm of As and then react them with KI....

Hi Pablo,

Yu's method is a possible solution to read the concentration from a standard curve linearized this way. Nevertheless, I suggest you to use your Prism software to fit the 4-parameter logistic directly, instead of the linear approximation on a log-log scale. To produce a calculation-stable fit, Prism needs the log of concentration as independent variable (X) instead of the original concentrations. Do not change the measured OD values (Y variable). Prism let you read the unknown concentration, it is a built in functionality. The advantage of using Prism (or any other similar sotfware with non-linear regression) is that you see your logistic curve, instead of just the transformed - linearized log-log values. Only the close-to-linear (middle) part of the standard curve might be used for determination of the unknown concentrations. It is rather straightforward this way, you can avoid the use of the lower and upper curving parts of the concentration-response curve easily.

Cheers, Karoly

Thank you all for your answers.

I would like to to give more detailed info that might be useful.

as Max Mittag already mentioned, the standard is IEC 61730.

The data can be found in Table 3 - Distances through insulation, creepage distances and clearances for class II PV modules. The material class and pollution degress of course depend on the PV modules and its mounting location.

Thanks to Bengt Jaeckel for his support.

Hi,

You can buy them at Alfa Chemistry. The links are below:

As with all of these things, it depends on the compound and what you want from it.

Amphetamine by HPLC cannot discriminate between (+) and (-) and you can only tell the difference with either a chiral mobile phase modifier/derivatising agent or with a chiral stationery phase or a chiral detector. Some other substances have significant conformational interactions or restrictions which would change the bulk structure of the molecule and therefore potentially affect the retention time. For a simple compound where it does not matter to you whether the compound is + or - but you just need the concentration, then simple HPLC should be suitable. If it matters to you whether your measured compound is + or - then you will probably need to try one of these alternatives. If your compound is biological then it is likely that there will only be one isomer present anyway.

Dear Asta, any standard with declared assay and purity is fit for the purpose provided you do not need to use some sort of certified material because the results of your work are intended to be used in regulated environment, such as GMP, GLP or HACCP. Then use the product recognised as a reference material in the respective field. As for the purpose of the study, I understand you intend to use standard addition to check the recovery rate of extraction. While you can certainly use standard addition to check the extraction from HOMOGENEOUS sample, the method is not suitable for checking the extraction yield from non homogeneous samples such as grains or flour. You may wish to use a reference material of the quinoa grains with certified amount of saponins (should one exist), alternatively you might use repeated extraction to calculate the yield.

Yes. Sub-size samples can be made according to ASTM D638; Type IV (width 6 mm; overall length 115) and Type V (width 3.18; overall length 63.5) will work.

You can focus on Cl (if no other Cl forms are in the sample) - you can burn s sample, trap the HCl and measure the Cl- ions.

If you know the retention time on GC, you can make "some approximation" of the content using different compounds for calibration and FID detector - the responce factors are not differing so much.

regards,

G

Amino acids can be dissolved in 10%ISO propyl alcohol

Usually a pharmacopoeia standard is designed for QC purposes and is not suited for quantatitive analytical method development as it doesn´t provide traceability. For such purpose, look for a "certified reference material" (a specific type of standard prepared according ISO 17034:2016).

It is not just the number but the quality of the reference also matters. An original article should have at least ten quality references.

Hi there,

RNAse from resuspension buffer is supposed to precipitate at the neutralization step and silica gel is not meant to retain protein contaminants. So RNAse contamination coming from your miniprep is not the main issue for cell free expression. The cell lysate you use as source of transcription/ translation machineries is more susceptible to RNAse contamination therefore adding RNAse inhibitor or using DEPC treated water for preparation of this cell lysate is necessary.

Hi, you can try with water-acetonitrile: 8-2, and see how the separation until water-acetonitrile: 5-5.

Hi Tamanna,

I'm curious, did you ever find an ASTM standard (or something comparable) for compression testing of hydrogels? Thanks so much.

Thank you Michelle for the update.

Dear Dr. Naidu,

In my personal opinion, your approach is correct.  However, I work for CBER and do not deal with biosimilar products. You should ask this question to someone in CDER/OBP.  If you do not know anyone in CDER/OBP, please feel free to submit the question through OCOD.

Thanks,

Lokesh

Thank You Fukada. It was helpful

Thanks very much Prof for your clear answer. But specifically, why does it rely on the area of the metal gate?

Talking about the back metal, does it a requirement to have a complete connection within MOS structure even though if we use p- or n-type Si substrate?

The whole point about the 2007 WHO standards is that they were based on a highly selected sample of women from 6 countries who were high SES, well educated, provided a constraint free environment during pregnancy (no smoking, alcohol, drugs etc.), and followed WHO breast feeding guidelines.  The premise is that such women produce babies who have equal potential for growth.  

Not sure what is meant by "successful" WHO standards.  If you mean do they accurately identify local/national growth patterns then the answer is usually "No" because they are standards of optimal growth not references of growth "as is".  Locally produced cross-sectional references ought to better reflect the absolute size of samples of local children but cannot be used to monitor the growth of individual children because they are not longitudinal standards. See the original WHO publications to understand the difference between references and standards. 

If you follow the Methods of the WHO you will end up with a growth standard that is not significantly different from the WHO standard.  My guess is that "local databases at sub-regional levels through local...studies" will not conform to the WHO selection criteria. It is also highly unlikely that any "local" growth study would take more than height, weight, head and arm circumference and perhaps abdominal circumference.  Few, if any, studies would have other anthropometric measures.  Also a "standard" is the result of a longitudinal study and I would guess that most "local" studies are cross-sectional allowing the creation of growth "references" but not growth "standards".   

Thanks for the answers. 

However, my sample (hose) is not suitable for dumbbell shape as per ASTM standard. In fact, according to the immersion test (ASTM D471), the sample should be cut into 50 mm x25 mm. Is there any possible method to determine the tensile strength, elongation and hardness for a product like hose?

For electronics industry, you can buy from www.IPC.org, or quality from www.asq.org.

I'm not sure you can directly find a database, but ACT has a research link on their website at http://www.act.org/content/act/en/research.html and may have a contact person or office there as well.

In my experience FTIR is used for a qualitative match.  We compare the sample with the reference standard.  They are usually prepared the same day using the same procedure.  The comparison uses the actual peak maxima.  You should have the same major peak maxima.  The peak size and shape should be similar, but not necessarily identical due to minor differences in sample preparation. 

Sometimes you may be using FTIR to identify an unknown.  When looking at an unknown versus a library the match percentage is your only approach.  Generally, a match at 90% or greater is a comfirmation.  The difficulty arises if you sample is not a pure substance. 

To estimate the LoD and LoQ you need to know the analytical signal (e.g. peak area), known concentration / amount of analyte producing this signal and the noise / background of the signal (in the same units as the analytical signal). So, you need to know the concentration / mass of the analyte and thus you should use SRM (standard reference material). This should be in possibly similar concentration range and form to your analysed sample.

You can try in this library http://bookzz.org/

There is also a handbook by Zwillinger, and for nonlinear first-order PDEs there is also a classic book by Kamke in German, see the links below the text.

Also, to complement the answer of prof. Stepien, Zaitsev et al. have an online handbook giving solutions to a number of nonlinear PDEs at

http://eqworld.ipmnet.ru/ ; in particular, see

http://eqworld.ipmnet.ru/en/solutions/npde.htm.

Finally, an important class of PDEs possessing infinite families of exact solutions, are integrable systems (see e.g. https://en.wikipedia.org/wiki/Integrable_system for details). For these, see the online Encyclopedia of integrable systems at http://home.itp.ac.ru/~adler/E/e.pdf

Dear Paploski

Thanks for the information. I appreciate it. 

Jeewaka

From my experience you will face the same situation / problem in every species you are working with. I usually go by the Royal Botanic Gardens, Kew - Plant DNA C-values database. http://data.kew.org/cvalues/

For maize it says the following: 2.73 pg Bennett et al., 1976

With flow cytometry the result will always vary depending on what you use as a standard and how you define the standard size.

I am not familiar with your experiment - if it simply for comparison purposes the absolute genome size is not that important - as you want to detect relative differences...

Nonetheless, you will have to decide on one.

Thank you very much, Eva Maria Temsch, and Andrew Rael, Armin Meister and T. Mates as well. That's very kind of you, and I am really grateful for that.

Have a good day !

Dear Taib

in South Africa we use these hot water system standards from the South African Burea of Standards SABS 

Gerro

You can use ISO 16343 and ISO 15603 standards.

You are looking for schedules for occupancy, lighting, heating and cooling, water heating, infiltration, internal heat gains from appliances, humans, etc... 

These values are usually standardized for different countries and they can be found in the national software that is used for energy performance of buildings. If you are working with Nordic buildings you need to look at THEIR standards and not borrow from other countries, as they may be different.

You also have to be careful when choosing the type of building e.g. residential, hospital, supermarket, etc... since the schedules would be different for each category.

Organophosphates are common AChE inhibitors. You can choose these substances to see AChE inhibition.

Dear Santana,

there is standard tests for measuring the Hydrophobicity. Static and Dynamic Contact angles also you could use for get an Idea about the Hydrophobicity.

This is the Standard Method. 

ASTM F21 - 14

Standard Test Method for Hydrophobic Surface Films by the Atomizer Test.

Actually, most researchers working with oxygen isotopes in different genera of benthic foraminifera use the so-called 'uvigerina' scale, so all genera are corrected to the uvigerina values. For carbon there are more discrepancies as uvigerina is an infaunal species and the measured carbon deviates from bottom seawater values. You can check this reference for a comprehensive comparison:

Shackleton, N. J., & Hall, M. A. (1997). The Late Miocene Stable Isotope Record, Site 926. Proceedings of the Ocean Drilling Program, Scientific Results, 154, 367–373.

Hope this helps.

Hello,

Internatial Units (IU) stands for a unit commonly used to measure vitamines, vaccines and meds. The volume or mass that stands for a IU depends on the concetration of potency of the substance, so you cant easy calculate. 

After a brief conversation with Mr. "Google" I found something that might work for you. You may try this lik - http://www.etoolsage.com/converter/IU_Converter.asp 

Good luck ;)

Sodium nitrate or sodium nitro prusside can use as a standard for nitrate estimation.

among antioxidant assay hydroxyl radical scavenging assay is have fen-tons reagent , but best method to evaluate total antioxidant activity is phosphomolybdenum and FRAP assay

You can use PCB 3, 14, 61, 127, 145, 204.

A surrogate standard usually has similar chemistry to the analyte of interest and is added to the raw sample (before any processing). Its role is to investigate the effect of sample processing methods on the analyte of interest.  For example you can use it to investigate recovery in an extraction procedure.

An Internal standard (I.S) on the other hand is added just before analysis. It helps to take care of variations in signal due to the instrument...The rule is "what happens to the "analyte" will also happen to the I.S. Therefore when you plot your calibration curve using the analyte:I.S ratio you get more accurate results

You don’t have to use any special buffer to dilute your samples, use water. Protein concentrations must be in the range of your standard curve. It’s better to dilute your samples because some components of protein isolation buffers can change the assay.

My protocol: 2ul of sample + 8 ul water + 200 ul of Bardford reagent (96 –well plate and multichannel pipette works great for it) triplicate wells for each sample, blank: 2 ul of protein isolation buffer + 8 ul water + Bradford

Dear Christof,

we have been looking for inexpensive quantitative standards for method development and QC and I have evaluated a decent number of proteins.

The application and the details have been published in Vasilj, A., Gentzel, M. et al., J Proteome Res, 2012 (http://www.ncbi.nlm.nih.gov/pubmed/22671763). The list of

proteins and further details are in supplement S1. Please note that myosin and actin were not suitable (solubility and multiple isoforms) and were not used.

Best regards,

Marc

My personal view is that it's almost impossible to get an SRM/CRM for every matrix in existence, especially one that's certified for the substance for which you're monitoring. The comparability of the physicochemical properties of the two matrices will determine whether the results are comparable. To Neus's point, numerous soil-based matrices exist, and depending on the analysis and extraction method, and the nature of the chemical you're analyzing, the results between two can be considered comparable.

However, there appear to be a couple of SRM's and CRM's for both inorganic and organic components in marine sediment (NIST SRM's 1941b, 1944, 2702, NIES CRM 12, etc). While it would probably be best to use matrices that are closest to your matrix, you could possibly make an argument for the urban dust depending on what you're measuring. Which compound are you looking at?

You might be able to get it ionized but you might be better off using a compound with an amine for positive mode or a carboxylic acid for negative mode.

Try out the NIST (National Institute of Standards and Technology) database: http://webbook.nist.gov/chemistry/

Not so good for compounds but very good for groups, their shifts and description of the whole process: The Hesse Meier Zeeh http://www.amazon.de/Spectroscopic-Methods-Organic-Chemistry-Manfred/dp/1588904881/ref=sr_1_1?s=books-intl-de&ie=UTF8&qid=1395160491&sr=1-1&keywords=hesse+meier+zeeh

Dear Zohaib,

Agreeing with Ian I consider the review papers as contributions that typically have (or "must have") long references section, otherwise they do not fulfill their purpose. Furthermore, 150 references is not too many, IMHO, in a geological paper dealing with a new geodynamic model of larger area this number is often reached, even if it is not a review paper.

Kind regards, Balázs

Hey everyone - very well informed debate here from those that seem to be well-informed and 'in the know'. I take your point Ian about journals, or publishing houses, wanting to format differently - but I don't see what is in it for them. I bet that many a hard-working copy editor/proof reader is wishing for the day that a universal system is adopted and, for that matter too, I think that most authors and readers would be happy enough as well - not having to differentiate between the nuances of say APA 5th and 6th edition!!

You can order cel-miR-39 at Qiagen.

The point you bring up is always tricky to address - but here's the way I try to explain this:

The context in which the target is presented to the qPCR will yield different efficiencies of amplification for that same target...

Whether:

Target A is presented as gDNA

Target A is presented as ds amplicon

Target A is presented as ss cDNA

Target A is presented as super-coiled double-stranded plasmid DNA

Target A is presented as linearized plasmid DNA...

Target A is presented as plasmid RNA

Target A is an in vitro transcript...

And also, for the above list, whether or not they were isolated from a

biological source or not will also affect performance/efficiency.

E.g., if you use purified in vitro transcript as the standard to evaluate virus isolated from your plant material, you still will need to know the efficiency of amplification of virus isolated from your plant material (e.g. do a serial dilution curve of infected plan material) - the biological extract of target will not perform the same as your purified standard curve material!

All contexts of Target A in the above list will have the tendency to amplify at different efficiencies using the same primers/primers-probe for the very SAME target; all on account of target "context" ... i.e., the different molecular geometries presented to the qPCR as "target" affect the initial qPCR kinetic directly for that target.

To confound things further:

A.K.A. "qPCR efficiency is not understood fully yet."

Name what you use, and use what you name; is the name of the game.

One context of a target does not confer kinetically identical behavior to the other possible contexts of that same target. Essentially, qPCR/RT-qPCR efficiency is not to be thought of as a 'constant' for all possible contexts of the same target. Efficiency is context-dependent.

So, we can only measure a facsimile of efficiency of any target depending on what costume it arrives in.

In your case, if you do have access to a readily-quantifiable in vitro transcript, and you can extract that quantifiable transcript the same way you've extracted your infected plant samples, you could then use it as a fairly reasonable standard that would allow you to compare and measure things on the right basis.

Your other option is to go ahead and use the cDNA approach - and merely report what you did. Stay in-costume as much as possible throughout.