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- 12Anyone familiar with placebo pills for method validation?
Placebo pills are needed to form a matrix for pharmaceutical formulations. If my company does not have budget for it, is it possible to use sugar-free pills and/or panadol tablets to compensate for its use? Can they meet the minimum requirement? In my humble knowledge, they have some although not all of the characteristics of the placebo pills.
Hi Kar-Weng Chan,
I would not recommend you to do that so. Herein, I give you an explanation.
As Vikram Shenoy mentioned, you can use panadol and sugar free matrices only you prove, it is similar excepients both in the type and amount of excepients. Because excepient can affect on drug release (in case of drug dissolution) or trap the active ingredient within the matrix. This is the example "Allwood MC. The adsorption of esters of p-hydroxybenzoic acid by magnesium trisilicate. Int J Pharm 1982; 11: 101–107."
For pharmaceutical excepients, we normally use "Handbook of Pharmaceutical excepients 6th ed" as a bible of our study. I hope it is very useful. In case of magnesium stearate, please see attachment in page 405, item "18 comment". It states the problem of magnesium stearate used, in amount used and even mixing time can affect to drug release. It also forms physical interaction with hydrophobic drug. For further information, please look at specific reference. (I send you the file by RG message.)
This is just an example of excepient affected on drug release (both in dissolution or drug extraction). Now I also work on %recovery. I still have a problem. Even I used drug finish product and spiked known amount of standard. I extracted with 50%methanol, 100%methanol and also acetonitrile. The percent recovery of 1 compound is about 93-95%, while the rest is around 100%. Fortunately, the %recovery is very precise.
From your last question, the used of panadol or sugar-free tablets, we cannot ensure that there is no excepient effect on drug extraction. If I were reviewer (for publication) or drug registration agency (drug registration process), I would question on this. I understand your situation. Is it possible to get information regarding the excepients used in buprenorphine tablet? What I know in Germany, they have so called "Red book" that you can find it (only name of excepients not in amount). I also found some article that they just added the most common excepient in different amount based on normal range in formulation. Then they extracted and compared (This increases a lot of work). Is it possible to ask for a gift of placebo from the manufacturer (sometime it works)?
This is what I know and try to answer with solid references (as we, scientists, have to do). :-)
I hope I answer your question.
- 5What parameters should I measure to prove that a certain drug enhance the immune functions?
i have a new drug and want to evaluate its effects on the human immune functions, what are the parameters should i measure to prove that this drug enhance the immune functions?
I agree with Thomas, Divaker and Kottarappat. It is important if you already have and idea of the molecular composition of the compounds you are interested in, i.e toxicity dose-response range. I will recommend you to use a mouse model in BALB/c or a C57BL ice and give the "drug" orally or by injection and quantitate the antibody response to a known antigen (albumin, globulin KLH etc) or sheep red blood cells and idetify if antibody response is affected. You can also determine lymphocyte proliferation.Following
- 1Which methods can be used for ROV image processing?
I am currently analysis ROV images from sandy and reef sediments, any suggestions on which method to use for image processing which can accommodate both habitat types. All the images were taken at 45 degree angle.
Drop the ROV and just look for image processing. ROV is just a single application of a generic process. If you need real-time, then search for "real-time image processing," but ROV doesn't really help your search.
One source of papers would be CVPR, another would be WACV. CVPR is a larger, more reputable conference, but WACV is more focused on the application side. I can't say that I've seen anything specific to sandy/reef sediments yet. Still, generic methods aught to work just fine.Following
- NewHow to measure the porosity of a titanium sample ?
What is the best way to measure the porosity of a titanium sample without using X-rays ?
Take slices of the samples and take surface porosity ?Following
- 31How can we proceed for decision on soil resource-based cropping sequence?
Development of soil resource inventory of a given area , is considered highly imperative to take decisions on the options about the suitability of different crops in a farming system mode. At the same time, the information on edaphological requirements of different crops , is equally paramount , so that both are super-imposed in such a way, to delineate soil-crop analogues. This will pave the way for better land utilization efficiency. My further querries in this regard are as follows:
* How should we develop a soil resource inventory ?. Shall we go for master soil pfofile stdies or follow the grid- based soil sampling coupled soil profiles to be later used for developing soil fertility variograms?.
* How shall we identify the soil fertility constraints of multiple nature from such soil resource inventory?.
* What methodology , shall we adopt to identify optimum soil requirement for different crops ?.
* How should we identify the cropping sequence based on such soil resource inventory?.
* Whether cropping sequence and land utilization efficiency are inter-related ?.If so , in what way?.
I request my esteemed colleagues to share their experiences on these issues. Regards
Dr.Deka I appreciate your interest in the subject .Your interest encouraged me to go through the publication last night.For some crops there is sufficient background data to fix the soil suitability criteria to rate the site into S1,S2,S3 etc categories. For some other crops the data is inadequate.But still I appreciate the efforts of the authors to develop criteria for all major crops.The second part is to utilize the suitability criteria for production of a crop / some crops in different districts of the country and rate their suitability.In a country like India to do this job or work for around 600 districts is Himalayan task.The third and most difficult task is whether we encourage or discourage farmers to grow a particular crop.Whether for the sake of maintaining or safe guarding soil quality or environmental protection will the farmers discontinue a particular crop or they go for a recommended crop if it is not remunerative for them.Ultimately who will enforce change and how?Following
- 1PAGE electrophoresis calibration for LDL subclasses separationMy research is aiming in detecting LDL subclasses using PAGE 2-16%. Does anybody know if the electrophoresis pattern (15V for 15 min, 70 V for 20 min and 125 V for 24h) has to be used for standards (e.g albumin and ferritin) as well? Do I have to run standards and plasma on the same gel or separately using the same pattern? Could anyone help me? Thank you in advance.
I do not know about it.Following
- NewWhat the best formula between 2^dCt and 2^ddCt for analyzing the data form stress and non-stress condition?
I try to study the gene expression between stress and non-stress condition, for example, I treat the sample with H2O2 at 37C for 1 h (stress condition) while the normal condition I incubate the sample at 37C for 1 h (same as stress condition).
What the best formula between 2^dCt and 2^ddCt for analyzing the data from stress and non-stress condition?
Thank you all.Following
- 3How can I create a variable that counts various visits with the time order?
I have a dataset with multiple visits recorded for patients. I want to use only data from enrollment for an analysis. How can I code so I limit the analysis for the enrollment visit?
@ Rafaelle. Thank you for your reply and sorry if my query was not clear enough. I am using data from a patient register in which the first record of each patient includes enrollment information. We have a date variable but I don't know how to select only the data of enrollment for this round of analysis. I am using stata.Following
- NewWhat is the most crude solution that an FPLC column (gel filtration) can manage?
I am considering assaying oligomerization of my membrane protein. I am wondering if it is possible to run a clarified mammalian cell lysate over a gel filtration column using FPLC. We have the ability to reverse the direction of the flow and so assuming that the complex lysate mixture will likely dirty up the column, we will plan to reverse wash the column after every run.Following
- 7What are the non-equilibrium conditions for thin films obtained by magnetron sputtering?
in some books it is said that the magnetron sputtering processes are carried out in non equilibrium conditions, but never are specified which ones; so that is my question, what are these non equilibrium conditions?, and how can I relate them with the phase diagrams?.
are these conditions contradictory?, in the sense that the phase diagrams are made in equillibrium conditions, and the thin film processes are not. g
Thank you S. B. Arnason.
I am agree with you, the sputtering process is very complex, and I am going to take into account your advice.Following
- 3Are dephosphorylated single stranded overhangs substrate for Mung Bean Nuclease?
I want to get rid of a restriction site for an enzyme in my vector. At first I tried to mutate the site by site directed mutagenesis but somehow it did not work. Then I adapted a straight forward approach to digest the vector with the RE in the question and then chew out the sticky overhangs by Mung bean nuclease digestion. I gel purified it and and religate the blunt ended vector. Unfortunately after screening few clones I see that they have same sequence as original vector. However the Gel showed that the digested vector migrated differently (slightly slower) when compared to the undigested control suggesting RE digestion worked. I suppose there might be two problems:
1. Mung bean nuclease digestion did not work efficiently and hence there were some sticky ends vector which have higher ligation efficiency when compare to blunt ended vector.
2. The RE digestion was not complete so some undigested vector were there which some how did not get seperated properly on electrophoresis.
Therefore I decided to dephosphorylate the RE digested vector before mung bean digestion so that even if the MUng bean digestion is incomplete, the dephosphorylated sticky ends will not religate. But I have a doubt that whether the dephosphorylated overhangs are still substrate for Mung bean or it only binds to phosphorylated overhangs. In my opinion this should not be phosphorylation dependent but please provide your suggestions.
If all you want is to get rid of a restriction site that leaves 5' overhangs, you can also "bluntify" your vector by filling the sticky ends with Klenow polymerase. The problem with mung bean nuclease is that it will cut your plasmid at any site that is nicked, which is likely to occur if your plasmid prep is old.Following
- 9Why does HEK293T detacht after transfection?
Hi, I was using costar 3516 6-well plate to culture HEK293T and reached the confluency 80-90%. Then I mix 1ug plasmid DNA with 2.5uL Plus reagent in 500uL DMEM. 10uL lipofectamine LTX reagent with 5oouL DMEM. I added the plasmid mixture into lipo mixture and incubate for 25min. Before transfection, I wash the cell once with fresh DMEM and then added transfection mixture. Right after that, the cells at the center of wells get detached and create an empty hole. I don't know how this comes. I do all the washing steps gently (dropwise). How does this happen? how can I improve?
Is there a specific reason why are you transfecting the cells at such high confluency?
So you know, I always transfect around the 60-70% confluency when the cells are in exponential growth. I found that by transfecting at lower confluency, you will obtain higher efficiency and the HEK293T's will be much less likely to lift away from the plate.
Also, you should be getting about 90% efficiency with HEK293T's, if not then try XFect.Following
- 13Are membrane proteins stable in SDS?We discovered in 2004 a correlation between protein kinetic stability and SDS-resistance. I'm not sure whether this correlation holds true for all (or some) membrane proteins. If membrane proteins are indeed stable in SDS, is it because they are kinetically stable or is it because SDS mimics the membrane environment? Are there membrane proteins that are not stable in SDS? For soluble proteins, a simple test for SDS-resistance is to do SDS-PAGE with 1/2 sample boiled and 1/2 sample unheated. If the unheated sample has slower migration on the gel, then that is an indication of SDS-resistance. Most soluble proteins will migrate the same distance on the gel, regardless of heating. Perhaps this assay will work for some membrane proteins?
Hi Dushyant: Thank you for your e-mail and excellent observation. Your example is the first one we have seen of a protein that appears to be kinetically stable and is not SDS-resistant. Is your protein also very resistant to proteolytic cleavage? If it is, then this would confirm it has very high kinetic stability in spite of its lack of SDS-resistance. I suspect it will be resistant to proteases based on your observations. If it is not highly resistant to proteinase K or thermolysin, then the protein is not highly kinetically stable. The sensitivity of this protein to SDS is very interesting. Is this protein basic or acidic? I wonder by what mechanism does SDS denature it? We have found many proteins from thermophiles and oligomeric proteins that are resistant to SDS (unpublished work). So it would be very interesting to understand what are the limitations of SDS-resistance as a probe of kinetic stability.Following
- 3Can anybody suggest a kit for labeling and isolation of surface proteins?
I'm interested in investigation of conidia surface proteins of phytopathogenic fungi.
- 1A result on composition of integers, how to prove it directly?
Result: The number of compositions of 2n, say c_1+c_2+...c_k=2n, satisfy that Sum_(i=1..j) c_i <2j for all j=1..k is equal to C(2n+1, n+1), i.e., the number 2n+1 choose n+1.
E.g., a(2)=C(3, 2)=3 because we can write 4=1+1+1+1=1+1+2=1+2+1.
Is there an easy way to prove it directly?
When you say directly, what do you mean? Give a bijective proof? Give a proof that both numbers satisfy the same recurrence? (The latter should be trivial, the former is the sort of thing that might be in "Proofs that Really Count", which would be a good first place to look to find how to answer your question).Following
- 1How gene expression is regulated?
All genes are not expressed at a time but how their regulation is maintained? Please describe with citation.Following
- 2Should I use tissue extracts or conditioned media for gelatinase zymography?
I wish to perform zymography for MMP-2 and MMP-9. I am working on cardiac remodeling and I have cardiac tissues as my sample to work on.
I am confused if I shall extract protein from my tissue or I shall isolate fibroblast and use the conditioned media or I shall simply perform in-situ zymography? Which way can give me best and reliable results.
I will be glad if someone can help me in this regards.
P.s. I can't afford a very high-budget work.
Thanks in Advance :)
Thank you for such a comprehensive answer :)
- 1How can we measure the contribution of actively managed mutual funds to market efficiency?There is extensive research suggesting that active management by mutual funds add little value, and more likely destroys value for the investor. Since this idea becomes more widespread, investors are now increasingly following passive strategies. There it seems that less and less investors are doing active research, and it makes one wonder when this eventually effects the level of market efficiency.
This raises a couple of questions, such as: are there other people working on this topic?, can we measure the level of market efficiency? How many active investors do we need for an efficient market?
The portfolio performance depends on the opportunity costs (of the transaction, of the no-transaction, of the liquidity) linked to the portfolio yield. According to banks and markets, these different costs are fixed, variable, direct or linked to the size of the assets. The only thing I know is : the active investors have to find their profit in the transactions, their transaction giving a free usefull information (the assets price). The number o active investor depends on their profit and the form of the opportunity costs.
- 25In quantum mechanics, we associate operators with physical observables. Why no operator form for the acceleration has been suggested?
In Dirac theory the momentum and velocity are not related by the simple relation p=mv. Will it be useful to look for an acceleration operator ? In that case shall we define an inertia for the de Broglie wave? Shall we than define a quantum force that acts on a matter wave resulting in jittery motion as demonstrated by Schrodinger as evident in Dirac theory?
"I don't think that physical theories are entirely made along these lines."
Testable theories are. Even your example necessitates the existence of "two coils". So we use the existence of something (effect) to cause the existence of something else (effect) and we think that we are talking about cause and effect.Following
- 2Can anyone please suggest literature which suggest why ESCs even from the same strain of mice, may develop at different rates?
Hello there, many of us working on stem cells already know that different lines, even from same strains or from same mother develop differently at times. It would be great if I could get some published literature on why this happens and in support of this view/ fact.
Thanks a lot.
I haven't yet explored the differentiation aspect of the lines in context yet, although that would also be influenced if there are differences in pluripotency state, of course. So for now, I am more or less talking about the generic pluripotency properties of these cells, viz., gene expression, proliferation rates, cell cycle analysis.. etc.
What I want to point out and also want to know more about is that while we compare 2 diff. groups in a study (e.g. maternal age- young and old), you would have differences in the properties of these ESC lines, even if they belong to the same group (e.g young or old), and not just that, but different even if they are from the same mother- even while they are treated in identical manner in vitro.
Do you understand my query now? I would also appreciate if you could suggest some literature I could look into.
- 6In what ways can we use data analytics to achieve educational goals or improve educational outcomes?
How can we use data analytics to improve educational outcomes? In what ways can we use data analytics to improve learning and teaching practices? Do you have any links that one can use to pull up literature review on data analytics or learning technologies?
Update: As pointed out, I needed to have specified the educational outcomes as this is a broad word. I will narrow it down to critical thinking and performance on test. I understand that performance on test can capture skills including but not limited to computational skills, problem solving skills, analytical skill and comprehension. So, how do we use technology to track if students are making progress in developing such skills? Thanks you all for contributing!
Very interesting how formulated the question.
Even agreeing to our friend Daniel Wright about what does the term data analysis, I will take the risk to say something.
The data analysis can be used:
- To see if the educational objectives are being achieved;
-to measure which abilities and skills students are acquiring or not;
-to compare our institution to the other;
-to see how factors associated with learning such as school climate, socioeconomic levels of students, organizational climate, etc. or others according to our interest, interfere with student learning;
-to measure the "school effect" and the value of an institution on their students;
-to measure the equity of education systems;
-to measure the academic performance of students;
-to monitor the performance and progress of students over time; ...
In our case here in Belo Horizonte (BRA) We are concerned with assessing which our students skills are building, keep track of whether the educational objectives for each year are being achieved and help schools monitor student performance to encourage more qualified educational interventions (mainly for students of low performance) from standard models evaluation. The characteristics of our country (high social inequalities) also have an interest too grating on the issue of educational equity and related factors, particularly those relating to cultural and economic backgrounds of students.
Then it will depend on what interests you most know but certainly a good database on factors and variables of interest you can help a lot.
For us has been particularly useful to work with educational indicators of factors that concern us, how these factors interrelate to each other, what weight have on student performance, whether the expected objectives are being achieved, what skills our students are achieving or may not have and how and why some schools succeed and others do not.
But from my experience, a good design of what matters to you, a good database and the right questions (which will dictate the studies to be made) can help you understand how things happen and help in decision-making, certainly.Following
- NewWhy HA-tagged ubiqitin wild type and mutated ubiquitin plasmids show different poly ubiquitination level?
I am studying on the ubiquitination's type on my target protein. I have HA-tagged wild type Ub, and HA-Ub- K48R (K48 mutated to arginine) , HA-Ub-K63R( K63 mutated to arginine), HA-Ub-K48 (ubiquitin with only K48, other lysines mutated to arginines) , Ub-K63(ubiquitin with only K63, other lysines mutated to arginines) in hand. They are in the same backbone. I tranfect them into 293 cells. However anti-HA western-blot showed mutated ubiquitins have lower poly-ubiquitination expression level compared with wild type. If they express at different levels, it is very diffcult to say the lower poly-ubiquitination level of my target protein is caused by ubiquitin mutation or the lower mutated ubiquitin protein level itself. Anyone have some experience on this field? Thank you very much.Following
- 2Looking for rare diatoms in our samples, from W-Iceland, Mediopyxis helysia, Stephanopyxis turris and S. nipponica. Taxonomic help would be great?
We ar looking for rare diatoms in our samples, from waters of Breiðafjörður, W-Iceland, such as Mediopyxis helysia, Stephanopyxis turris and S. nipponica. Taxonomic help would be greatly appreciated. And cooperation in the taxonomic work would be very helpful..
Thank you very much. I will do that!Following
- 39Are there any practical strategies to get less confident students to talk? both for elementary and intermediate students?
I have classes with both EFL intermediate and lower intermediate students; how can I encourage them to talk esp. those who are less confident
Try to be pedagogue enough.You could motivate your students ,through visualization of a real problem situation,pulled out during a brainstorming session .Students are more confident,once they visualize a problem situation of their real life.Start with a concrete problem of their daily life .Provide your student, the opportunity of a mental representation ,based on his background,in relation to the problem situation..Following
- 1How can I create a simulation box with periodic boundary condition to study interaction between metal & organic molecule surface?
How can I create a simulation box with periodic boundary condition to study interaction between metal & organic molecule surface?
If you have one dimensional system then you have the value of the function and its first derivative at both edges are equal to each other as boundary conditions. For the higher order domains you have to use the generalized Fourier series expansion taking the computation box as a basis for the set. If you use the collocations points for the numerical integration then it is better to use discrete Fourier transform for the selected computation cell, which I have done in many times in my work.
Note: I hate to use periodic boundary condition for your case, which may not create nonequilibrium stationary solutions at the ends. That happened many times in the literature for those problems where the people were looking for an ordered ensemble of quantum dots ( the pattern formation i 2D) associated with strained -hetero-epitaxially grown thin films on rigid or deformable substrates, without luck.Following
- 2What may be the possible issues arising when converting shapefile to aoi in ERDAS imagine 2014?
while trying to convert shapefile to aoi, everytime blank aoi is created without any dotted line. I am aware of the simple conversion steps, but in my PC i could not do it successfully. plz help me with your suggestions.
its easy, the problem is, it change in ERDAS 2013-2014, check this steps:
1.- Open a shape file in ERDAS
2.- Select the shape file
3.- in vector tab (Drawing) choose Copy (at the left)
4.- In file choose new/2dnew/AOILayer
5.- Choose in home tab "Paste" (From selected object), it is on the right form comun Paste button.
6.-Save as (AOI layer as)
thtas all, its work for me every time.
- NewHow to maximize a smooth function defined over [a,b]?
Suppose we have a nice differentiable function which is defined on [a,b]. What is the better approach to maximize it?
Thanks in advance.Following
- 25In GR, can we always choose the local speed of light to be everywhere smaller that the coordinate speed of light? Can this be used in a theory?
It seems that many, if not all, solutions of Einstein's equations, such as black holes and grav. waves, can be given coordinates x\mu in such a way that the local speed of light is always slower than the coordinate speed of light. Think of gravitational lensing: the index of refraction of a gravitational potential always seems to be >1, in practical examples, so a gravitational potential slows light down, and never speeds it up (if coordinates are chosen carefully). This wouldn't be true for a negative-mass Schwarzschild solution, but that seems to be outlawed in nature.
Now this was only a conjecture, I have not attempted to prove it. How would a rigorous mathematical theorem be formulated? And did anybody - and here I mean a wise person, not the average blogger - ever try to do something interesting with this observation? Like constructing a “hidden medium” for curved space-time?
@ the poor sol awarding red points without reading or understanding please contact a good Psychoanalyst ...... Adolf Hitler started your way..... sorry for every one else......Following
- NewHow can I modify the surface of CdSe/ZnS quantum dots with thiolated glucose ?
I use toluene as solvent. Do you have any suggestions for the conjugation procedure of quantum dots and glucose molecules?Following
- NewRegarding CAD geometry for computational fluid dynamics simulations: How do I ensure "watertightness"?
I create CAD files in a CADing software and need to import them into a meshing software for my CFD simulations. Cracks appear in the geometry during the process. A micron level confirming to boundaries is essential. It is therefore too difficult to find all such cracks manually and repair them. I have a centimetre sized object. Looks like the appearance of cracks is inevitable and softwares do not seem to provide an automatic size based crack repair (understandable, as the software is supposed to mesh, not repair boundary mistakes) Proving to be a real spot of bother. Thanks in anticipation.Following