ResearchGate Q&A lets scientists and researchers exchange questions and answers relating to their research expertise, including areas such as techniques and methodologies.
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- I have required the following research papers: -
I have required the following papers:-
Higashimura, M., and Fukui, Y. (1988), ‘Realization of All-pass and Notch Filters Using a Single Current Conveyor’, International Journal of Electronics, 65, 823–828.
Soliman, A.M. (1999), ‘New All-pass and Notch Filters Using Current Conveyors’, Frequenz, 53, 84–86.Following
- Are you using a Q-Exactive MS instrument to analyse epigenetic/proteomic systems, what limitations have you found so far with the hardware & software? Does anyone have example instrument hardware settings for analysing proteomic samples from e.g. a HeLa digest. Also any "tips and tricks" that you have picked up would be most appreciated.
One really good place to find MS settings for many instruments (including at least 12 Q-Exactive datasets) is ProteomeXchange.
- PCR product shows a smear in the gel I loaded a PCR reaction on an agarose gel and I get a long smear with my band a little more intense in the smear. If I dilute the DNA I obtain my band but not perfectly clean from a sample. For some samples the simple dilution did not work. Does anyone have advice?
I'm facing the same problem now, I really would like to know how peole solved this.Following
- Is their any relationship between rate of Chl a-fluorescence and chl a concentration?
Please let me know in terms of F0, Fm , Fv/Fm.Following
- How to build a teamwork culture in universities?
Building a conductive environment to teamwork in universities is a process requiring a plan and specific activities to support the teamwork solidarity.
The team work is basic fundamental part of the any good acceptable character as general. it is unacceptable to be individualize in the current one village world. Universities and any company should look for this character (team work) and should be part of the required CV
- Why am I getting low MAb expression in DG44 CHO cells?
I am attempting to express a mAb in DG44 cells. I am using pcdna3.1 with the ovalbumin signal peptide and using the amaxa electroporator for transfection (5 ml cells with 1ug/ml dna). I am seeing very low expression (20 ng/ml) via ELISA. I have tested for efficiency with eGFP plasmid and it seems fine.
What is the most obvious thing I am doing wrong or is this low expression simply normal in dg44? Would it be possible it if is abnormal to compare this to a control vector for mAb expression in DG44?
Numerous parameters are critical especially DNA cassettes, transfection method and cell culture conditions. You could also consider using an alternative to electroporation for mAb production. For example I can recommend HYPE (http://www.ozbiosciences.com/transfection-bio-production/39-hype-5-dna-transfection-kit-protein-expression.html) which is successfully used by several pharma for bioproduction for example you can see production of antibody in CHO cells with HYPE in this patent http://www.google.com/patents/WO2013117647A1?cl=en
- Where can I find the significance of the cointegration coefficients in the output of cajorls-function in R? I'm investigating some cointegrating relationships but the output of the cajorls-function does not provide the significance of these cointegration coefficient. Can I look at the output of the cajools-function?
You have to run extra code. In the following link you can find an example:
Check the supplement v27i04.R.Following
- Can there be duplicate genes on different chromosomes (not through transposition)? What are they called?
I work with a set of 3 conserved proteins that have similar function, very similar structures and about 50% sequence identity. The genes for these proteins are, however, present on different chromosomes. Is this event possible through duplication? Can such proteins/genes be called isoforms?
Complete genome duplication to tetraploidy or higher polyploidy is rather common in many lineages of eukaryotes. http://www.macroevolution.net/prevalence-of-polyploidy.html Determining whether your gene/protein was duplicated during a polyploidy event, or some time earlier or later, may be possible. Are the 3 copies exactly equidistant from each other (same percent amino acid identity/distance)?Following
- Can i use zebra fish model to find out brain antioxidant activity of aqueous extract of some fruit seed
i want to check antioxidant activity on brain , so is it feasible to use zebra fish in place of animal modelFollowing
- Why are peaks in XRD patterns of nano-size materials wider and less intense?
In comparison to micro meter size materials, nano-size materials exhibit wider and also less intense peaks.
Concept of physics point of view, the crystallites are mainly responsible for the diffraction / reflection of X-ray just like the reflection of mirror. In case of light and mirror, when the size of the mirror is small the intensity reflected light is low. Similarly, in X-ray physics the crystallite size is inversely proportional to the FWHM of the diffraction peak (Scherer's formula), hence small particles or crystallites generally produces broader peaks
- How can I differentiate thin wires of non sag tungsten of different grades and manufacture? I dont know the recrystallization temperature for the wire. How can I determine it?
for GLS filaments and FL electrodes the K content typically amounts to 65 - 75 µg/g, for halogen lamp filaments 70 - 90 µg/g. The recrystallization temperature depends on the amount of deformation, the TMT (deformtion temperatures, heat treatment temperatures) and the potassium bubble distribution. Typically, the onset temperature (annealing time= 15 min., heating rate= 3 °C/s) amounts to 1700°C up to 2100°C (the higher the degree of deformation (the thinner the wire), the higher is the recrystallization temperature).
All the best for your work, GerhardFollowing
- How do you remove saponin content from plants samples?
In grasses, if having high saponin content; how to remove it without disturbing plant other macro molecule arrangements or percentage.
And will it work perfectly with ethanol or water boiling without affecting plant natural properties?
- About CO2 Photoreduction. Can anyone help?
The major product from my photocatalyst is methane. But the valence band edge of the photocatalyst is less positive than the oxidation potential of water. It means that the holes produced in the valence band of photocatalyst won't oxidize water to produce H+ which would then facilitate the CO2 reduction to CH4. Can anyone please help me how to justify this or if you can provide with some suitable literature addressing such case. I would be grateful!
Just curious about your conditions, is it water and CO2 only?Following
- Can you identify this model from Medical Teaching on the run?
I have misplaced a model! I am writing about teaching on the run for doctors, and I have the one minute preceptor, aunt minnie (Which I don't like very much) and SNAPPS models, but I know that I came across another model a couple of years ago that was a double loop model involving patient, learner and clinician which I remember liking a lot, but fail to remember who's model it was and where I saw it. Any suggestions?
Regarding teaching with patients, something to add to that is simulation labs? This is growing. I am also very interested in education and across healthcare organizations, there is such an immense mgt of students, University, research development, EHR use, data mining and simulation labs, along with other CME https://harvardmedsim.org/Following
- Does anyone have information on the latest Finite element model updating methods?
I want to tune natural frequencies of first few modes of vibration of a shell. Which are the best iterative methods for finite element model updating of above mentioned problem.
I have seen it. Any other work you know of ?Following
- Filling of microchannels
I want to buy some automatic control system to fill micro channel of height around 50 um and width around 500 um. Dose any body has an idea please suggest me . I fill it manually with injection syringe via capillary tubes.
- Can we mathematically model consciousness? We have seen that AI, which was supposed to be a failure, is coming back with
gusto on the back of multi sensor robotics and possibly androids with quantum computers. There is some mysterious counter intuitive behaviour in the sub atomic world which seems to suggest inanimate objects do sense the external world.
It would be nice to know the views of experts from different fields, such as math, science, psychology, sociology, cosmology on this intriguing subject. One possibility
that comes to mind is if probability is actually such a model, as it does incorporate
Many thanks for sharing your ideas with us. I am not sure that I agree with you. It is true that cognitive neuroscience almost by definition lacks the stringency and “simplicity” of the more traditional so-called classical areas, where we know what is required to embrace paradigms and to understand mathematical models.
For a scientist who wants to create new knowledge and understanding he/she must work hard and not be afraid of, as we say to make his/her hands “dirty”. You have probably heard the story communicated by Crick (via Vilayanur Ramachandran):
Question (from gentleman philosopher): But Doctor Crick, you haven’t bothered to define the word consciousness before embarking on this.
Response: I’d remind you that there was never a time in the history of biology when a bunch of us sat around a table and said, ‘Let’s first define what we mean by life.’ We just went out there and discovered what was – a double helix. We leave matters of semantic hygiene to you philosophers.
Although much of your response to Yingxu Wang conveys our common lack of understanding, I am a bit perturbed by your devaluing almost bantering approach.
We have long ago more or less agreed that the answer to the question posed to this thread is to be answered in the negative. Nevertheless efforts like the one above are very important even if the end result may not be what was hoped for or expected.
I might aver that even if “a mathematics based on a faulty model may be the best mathematics in the world, and the result is still considered “junk”, the effort is important as part of a communication – learning process. I have posted many comments on RG threads on the importance I have given to the concept of “communication”, so I will not repeat the details again. Communication is a process that defines life not only between humans, animals and flowers. It is embedded on the most fundamental level of nature.
My take on Yingxu Wang’s idea of abstract intelligence could also be instigated in connection with the concept of communication as the latter is nothing but a natural process that transfers information into behaviour and knowledge.
We use computer metaphors and mathematics to convey our insights and arguments as succinctly and exactly as possible. I have also stated here and in other threads (cf. the Penrose controversy) that Gödel’s theorems rule out the main assertion that any life form from e.g. an earthworm to a human being can be simulated by a computer. This, however, does not impart that fundamental research in AI, if based on faulty mathematical models does result in "junk". This is not the way science proceeds!
Your view on the scientific process seems a bit limited to me. Science is the art of knowing and what you define here is the process of research as accumulating knowledge by systematic observation, deliberate experiment and rational theory. We cannot look away from the close connections with practical techniques, technologies, the practising of arts and, even the spiritual sphere, as it all defines the material culture of our Society. Science evolves as everything else according to the paradigm of evolution and the only trap is the self-referential traps of Gödel, Cantor, Russel etc., which we need to be aware of.Following
- How can a patient with recurrent Pseudomonas bacteriuria following cystoscopy be treated?
Recurrent Pseudomonas bacteriuria treatment.Following
- How long can fixed cells can be kept (at cold) until flow cytometry analysis? I am looking at one of the viral protein expressed in the BJAB cells.Currently, I'm doing the internal staining after fixing and permeabilizing the cells. Since there are different time points, I was wondering if it is possible to prepare the samples and run flow cytometry all at once. Thank you!
Interesting! I thought fixing cells distorted the cells in some way which made it unsuitable for flow cytometry. Therefore, I always tried to use live cells as fresh as possible.Following
- Is there a method for quantifying Nisin A by RP-HPLC?
I need to quantify Nisin by RP HPLC in a preservative product for food. Thanks.
Nisin, as monensin is a ionophore. They share some structural similarities, my guess is probably a post-column derivatization with vainillin in methanol and sulfuric acid will do the trick (a pink colored derivative is obtained for polyether compounds such as monensin, lasalocid and salinomycin and maduramicin) if you a are using VWD/DAD detection. See for instance: AOAC 997.04; J AOAC Int. 80(4):693-702. Hope this helps.Following
- How to find minimum ihhibitory concentration
i have a data showing antifungal activity of some plant extracts. i want to calculate minimum inhibitory concentration of these extracts. can anyone tell me how to do this.
A very good example found at researchgate using google. :)Following
- Is it possible to observe sustained interference pattern from two independent laser source?
There will always be interference. The question is how quickly will it change. One typically has to work hard to get two lasers stabilized well enough that you can easily observe the interference.Following
- Neural Network Modelling
Hello i would like someone to tell me how to test trained artificial neural network in matlab for linear predictions.Following
- Can anyone suggest any research on the perspectives on LGBT (lesbian, gay, bisexual, transgender) among different cultures? I am interested in the cultural perspective regarding the development of our gender, as I believe that our culture affects how we view this concept. Particularly, I would like to know the research done regarding this topic in different cultural contexts.
you may find this interesting
- Do you think that a two-laser-beams-in-vacuum collision will produce a positron/electron pair?
Considerations of a numerical vacuum-structure suggest that electron/positron pairs can be produced by colliding photons under defined theoretical circumstances. The event is supposed to occur spontaneously in nature too, but only effectively in vacuum. This sequence would be the opposite from the often measured positron-electron annihilation. The result of the experiment could assist to understand the location of antimatter (of this sort) in the universe and the role of the structure of the vacuum. The problems of constructing the proper vacuum chamber as well as the difficulty of the measuring devices and their noise level thematic are supposed to be understood and controllable. What is your opinion? Is it an experiment worthwhile to be conducted?
I think it is possible with gamma rays of the same frequency, propagating in opposite directions (in at least a system of reference), so the total momentum is zero.Following
- 3d printed electrochemical cell for pyrrolidinium TFSI (or chloride) RTILs
Does anybody know which filament is suitable and compatible for 3d printing of electrochemical cells for pyrrolidimium TFSI or chloride RTILS?
Is ABS compatible? maybe PLA?
It may be required for experiments at temperatures up to 70-80 centigrades - I believe it may be an issue.
I will appreciate every good advice.
Your working temperature has basically ruled out PLA for you. PLA's glass transition temperature is around 60 centigrade, so at 70-80 centigrade it starts to become soft and the shape won't hold up.
ABS, on the other hand, has glass transition temperature around 105 centigrade so it will withstand the temperature just fine. But I am not too sure if ABS has the chemical resistance for your application. I know ABS can hold up against some acids, but it swells in some too.
You can print a small part in ABS, and then test its chemical resistance in the liquids you intended for your application. If it holds up fine, then you might want to print your model and test its performance.
Another filament worth considering is nylon. But to print in nylon would require some tweaking of your printer and it would be helpful to know which printer you are using. However its good to keep in mind that nylon has a tendency to absorb water and that may not be suitable for your application.Following
- Has anyone done a total pancreatectomy during a planned Whipple procedure?
Soft pancreatic remanent.
I personally did not, but it was done in our department. But there is rarely an indication! Leaving behind a small remnant of the pancreatic tail with/without anastomosis or even blocking the pancreatic duct seems favorable to me to avoid or ameliorate the postoperative diabetes. I know some patients without pancreas and their life is not very comfortable or secure even with modern therapies.Following
- My C57BL6 mice are fighting alot, what can I do to prevent this?
I'm currently under the experiment with C57BL6 mice, male, 8 wks
Q1. They fight a lot, what can I do for this?
There are 6 mice in each cage initially, and I have been separating the most aggressive one from the cages, but it seems I need other solutions..
Q2. Is a fight without bleeding or severe injury admissible? is this just normal thing?
Q3. What do you think if I use female mice rather than male mice for liver metastasis model? (Cell line: MC38)
I'm afraid I don't know anything about the model you are using, but I have some suggestions for fighting (I used to be an animal technician).
When cleaning out the cage, some of the dirty bedding or sawdust can be transferred to the new cage. Mice often have to fight it out when they are put into the new clean cage, as they are missing all the smells telling them who's in charge. I don't know how strong the evidence is, but a technician colleague presented a poster saying this helped with fighting, and ever since then I always do it. It sounds gross, but mice like the smell of their own urine. Also make sure the cage has some enrichment, like a small tube. The weaker males can run in there to escape the dominant mouse. Finally, ensure they are not exposed to a stressful environment. The smell of unfamiliar male mice will upset them. Lots of sound in the room where they are housed is also stressful, and bear in mind mice can hear in much higher frequencies than we can. I have known building works to causing fighting and pup-eating before.
That said, some fighting is to be expected. Mice maintain a hierarchy in their cage, and enforce it with fighting and grooming. You will especially notice this after cleaning out, as I said before. If there are no injuries at all, I think it might be worse to split them up, as they are social creatures, and are stressed on their own. However, if they have lots of scabs and injuries, they can't be left to be bullied. I can only say what is admissible by the UK Home Office though!Following
- What are the clinically used biomarkers to detect Diabetic Pancreatic Carcinomas?
There are many biomarkers for the detection of pancreatic cancers, leading the pack is CA 19-9 whose sensitivity and specificity is less than optimal. In clinical settings, are there any other markers that has proved more useful in detecting diabetic pancreatic cancers?
Maybe it is a long shot, but feel free to have a look at this.
Protein arrays bypass the genomic biomarker discovery and validation stage and focuses straight away on biomarkers that are detectable in the blood stream. There have been many promising biomarkers been discovered in biopsies and tissues that never translated in biomarkers that are detectable in the blood stream. This was always due to dilution effects from and markers are not sufficiently expressed on the proteome level.
There are a number of diseases and applications such as predictive as well as efficacy biomarker for research and for clinical trial monitoring.
Cancer and Autoimmune Disease biomarker discovery
Protein array studies can be performed as a service comprises guidance with study design, performing the lab work and data analysis all in one package.
We have already performed more than 50 biomarker studies all around the world.
Quality arrays with a lot quality controls:
These arrays were designed for large scale well controlled biomarker discovery studies
> auto-fluorescent marker for laser power QC
> catcher antibody dilution series for secondary IgG, IgA and IgM
> probes for measuring cross-reactivity of antibodies
> fully active and native proteins