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Biomedical Instrumentation - Science topic

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I am working on a project on biomedical instrumentation. So, in the data samples we have only taken  five different values of pressure and corresponding to that we have measured around 80 values of voltage each. The issue that we are facing now is we are not able to find a suitable relation between pressure and voltage, for example for any particular value of input voltage, our instrument should give pressure as output( not necessarily from the same five values of pressure). Can anyone suggest which regression model should we imply? 
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You can try the Multivariate Linear Regression Model,
You can look into K Matrix and P Matrix Calibration Models in this regard, the following book discusses in depth the mathematical development of these models:
" Mathematical Analysis of Spectral Orthogonality"
by Kalivas and Lang
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Hi RG,
I'm looking for a blood pressure device/module/kit which outputs raw data (serial or wireless, digital or analog). Usually, the information from these devices is on-screen only or, if Bluetooth, connected to an app that does not permit you to access the raw data.
I need to develop an instrument that measures the pressure data from the sphygmomanometer and processes it in a microcontroller to send it elsewhere.
I couldn't find this kind of solution anywhere. I'm already thinking of buying an analogical sphygmomanometer and hacking a pressure sensor in it. What do you think?
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To build blood pressure of a human you need to the cuff with an air pump to increase and decrease the pressure slowly to control the flow of the blood in the arm such that one can find the systolic blood pressure and the diastolic pressure.
Where the systolic pressure is the onset of blood flow after stopping it by higher pressure in the cuff. The diastolic pressure is the pressure at which one can no longer hear the pulses of the heart at the end of the pressure release stroke.
So you need a pressure measuring tool and you need a microphone to hear the pulse rate and the blood flow in the arm after the cuff away from the shoulder.
The relation between these two signals indicate the required points of the blood pressures.
You need to acquire the signal from these two sensors and process them to get the blood pressure points.
Best wishes
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I am currently using the Seahorse Bioscience XFp to characterize my cells and assess their baseline energetic activity. However, I am having some difficulty in measuring the DNA content, as the wells of the plates are 40% smaller than a regular well of a 96-well plate. I am also using Hoechst dye 33258. However, increasing the dye concentration affects the linearity of my standard curve and my samples often do not fall on my curve. I currently normalize with protein but prefer DNA. Any assistance provided will be greatly appreciated.
Trudi Denoon
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Hello Trudi, I was wondering if you were able to find the solution to this problem? I am currently struggling with this as well. Thank you.
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I am a master candidate, i need to do a thesis related to the topic.
I would like to know your ideas about updated research topic on the field of controls and biomedical instrumentation.
Thank you.
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I would suggest applying the Internet of Things (IoT) for health care for the elderly.
This theme enables numerous possibilities of working in Instrumentation and Control.
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I have been trying to data and wave capture from Philips IntelliVue Monitor using Matlab for our research studies in real time. Does anyone have some code they are willing to share? The community's help in this important matter?
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There are two types of connectors on Intellivue platform, the MIB (ISO/IEEE framing) which is similar to RS232 but has a RJ45 type connector with specific wiring. The other type is regular LAN port which can be connected to a PC via a crossover LAN cable or even a regular crossover cable with Internet sharing or router configuration. See some details here: https://sourceforge.net/p/vscapture/discussion/general/thread/d87f964f/#32be and here https://sourceforge.net/p/vscapture/discussion/general/thread/cb369fa9/
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We are working on dry electrodes and are wondering how to understand chemically what happens.
  • How exactly are gel based silver electrodes measuring electrical activity? (how are electrons produced, what is happening at the interface with the skin, how is it related to the electrical activity of the body?
Thanks a lot :)
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William J. Croft Many many thanks. You are a life saver. I was looking for this info for about 2 months, to no avail.
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Photo-acoustic biomedical instrumentation will be a trend in the future. It uses very high sound frequency (in 100's of GHz) way above ultrasound range (1MHz to 18MHz). If there is anyone who is familiar with the technology, who is working with such a project, please let me know and give some of your ideas here.
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Sheryl Roberts , M. Manivannan , Subhamoy Mandal thank you foe your comment. Sheryl Roberts , thank you, I appreciate your suggestion, I will do that.
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Hi everyone,
I have been having problems with lifting off my devices. I thermal evaporate Cr (5 nm) and Au (60 nm). Apparently, the Au doesn't want to come off completely. I have severe cross talks between channels because the Au are still connected between the interdigited fingers.
I cannot ultrasonic my sample because my sensing material, graphene will rupture right away. I can only agitate the stripping solution lightly. Please advise!
My procedures are as following:
(1) SPR 220
Equipment: Spinner
Spin SPR 220 at 500 rpm for 5sec (acceleration 250 rpm/sec)
and 4000 rpm for 40 sec (acceleration 1000rpm/sec)
Recipe: Supposedly 4 um according to data sheet
Softbake: hotplate 30 sec ramp to 115°C then hold for 90 sec
(2) Photolithography of Mask
Equipment: Karl Suss Mask Aligner
Recipe: Exposure
Hard contact mode
Expose: 38.3 sec [ Photospeed around 345 and Intensity: 9 ]
Development: MF-26A (80 s)
Rinse with DI water and dry with nitrogen gun
No hardbake
(3) Cr and Au deposition
Equipment: Kurt J. Lesker Thermal Evaporator (Nano 36)
Recipe: low deposition rate
Thickness: Cr 5 nm then Au 60 nm
Time: 1 hour
(4) Metal Liftoff
Equipment: Wet Bench
Recipe: Soak the substrate in Acetone bath at room temperature
Time: 1 hour
(4 Alternative) Metal Liftoff
Equipment: Wet Bench
Recipe: Soak the Stripper 1165 at room temperature or 80 degree celcius
Thanks in advance!
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How would I know if I have the right development profile?
I understand that undercut structures are easier to lift-off, but how would I know it is undercut?
Since the thermal evaporator is down currently, I am depositing the Ti/Au 25nm/50nm instead of Cr/Au.
I am still having severe problems with lift-offs. During the lift-off, I can see the wrinkles form while sitting in Acetone, but it doesn't lift off even overnight. If I were to squirt Acetone on the structures, a lot of my intended structures get peeled away.
Any suggestions?
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I am an electrical engineer and a doing my post graduation in instrumentation and control. I want to work in the field of biomedical engineering like bio medical instrumentation and bio medical signal processing. suggest me some areas which will be suitable for me to work.
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Dear Dulam
i suggest the below topics
1. Smart biosensing using AI-based approach (instrumentation and control)
2. Intelligent recognition of primitive cancer  using new metaheuristic or AI-based methods (image processing)
3. Optimazation of ECG signal (or other medical signal) storage using new hybrid techniques (control and signal processing ) 
i hope that these suggestions will help you
best regards
Khalil 
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Which is more accurate among all commercially available personal glucometers to measure glucose concentration in water-glucose samples? Is there any rating available for personal glucometers based on the performance? 
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Hi Satish ¡ I agree with Tausif obout the use of blood glucometers  for measurement of glucose in wáter. You can be sure with the measurement of glucose in kown concentrations in wáter on   several  solutions prepared by yourself
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I am working on psychoacoustic active noise control. I want to design an psychoacoustic model for sound quality measurement. I went through the book of Zwicker's loudness: Psychoacoustic Facts and Models.
I am not able to understand how to write the program in matlab to calculate the loudness.
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Good question and good answer :)
Perhaps a little late, but there is a toolbox available which contains matlab implementations of a number of loudness models, which I've found useful in the past. http://genesis-acoustics.com/en/loudness_online-32.html
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I have obtained impedance spectrum for single cell in experiment.
How to extract parameter in equivalent circuit based on this impedance spectrum?
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Prof. S. EL-Rabaie is right that are your options. I want just to expand a little more. In Matlab, you can call the function fminsearch(f,x0) with your specific objective function and a initial guess. with your data it will find the best fit for your data and return a vector of parameters X. There is a third option but is more complex and suffer from horizon limitations. You can use neural networks of GP to learn a model over your data.
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Previoius studies showed that it is possible to evaluate fetal heart rate by heart sound signal. I wish to examine the previous methods.  I am grateful if someone can share fetal heart sound records with me.
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Mr Parth Shah and Mr. Hong tang,  I've downloaded this link, but how to open the file. I can not open. Please help me out, I am having some trouble figuring out how this work,
Regards Irmalia
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I am not professional about compressed sensing (CS). I know CS can reconstruct the texture of the original image from highly undersampled data if some conditions are met. However, I have no clue how CS algorithms do to the noise. Is it possible that compressed sensing reconstructed image in MRI maintains or improves SNR comparing to fully sampled original image?
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A noise reduction (or SNR improvement) due to the CS reconstruction is certainly possible - however, typically associated with loss of resolution or image details.
Compressed sensing reconstruction can be implemented using a total variation (TV) penalty in addition to an l1-norm sparsity objective. The TV penalty performs additional (edge-preserving) denoising of the resulting image - look e.g. for "TV" or "denoising" in the article reference below. (The strength/extent of denoising is controlled by the weighting factor (alpha) of the TV penalty.)
(TV denoising can also be applied to other MR images - independent of CS reconstruction; this will also improve the SNR, but potentially remove small image details.)
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I am developing an instrument - A. I have calibrated it against a reference instrument B which is believed to be very accurate. Now, I again tested 13 fresh samples in both the instruments and found out the percentage errors. Does it make sense to report a Bland Altman plot analysis to measure the agreement between the two instruments ? Technically one instrument - A is calibrated based on the reference and accurate instrument - B.
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Well Kaushik,
I do agree with what Dreher is saying.
1) What you are comparing at present is the "SAMPLES" using both instrument A (Standard Reference Calibrated) and Instrument B (as developed by you)
2) As stated by Dreher, I too agree to introduce the "REFERENCE SAMPLE" to be tested using both the instruments A and B
3) But, going a step ahead, what I would suggest is to make or test your "SAMPLES" (those 13 samples) and this "REFERENCE SAMPLE" to a third party well-calibrated instrument such as Calibration Laboratory to validate the results.
4) Kindly keep in mind that no matter what algorithm or method you use to estimate the error, you sample results remain the same.
I hope you find it useful.
Best wishes!
-Prasanna Waichal
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I am in need of detecting Inspiration phase of respiration cycle continuously in real time suggest me the best sensor type (Flow /Pressure /Thermal)?
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A suitable option is to connect a 3-way connector in line with oxygen supply (nose prongs) and attach there the extremity of a pitot tube connected to a pressure sensor (this is a version of anemometer).
The cost of this setup is around 30 dollars.
Andre
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I am hoping to find answers for an issue that I am facing when using LumiCycle from Actimetrics. I have been using U2OS cells with Per2-Luciferase in it, which has given me stable rhythmic outputs consistently. Over the last few months, I have encountered a strange problem when the signal dies off at the end of Day 3 after plating while previously it used to continue till day 7. This problem is erratic as it comes and goes. I have changed the batch of my cells, used fresh lumicycle media, luciferin, cell densities while plating etc. When the signal is lost, the cells still look healthy and there is definitely no contamination in the media, nor is there any loss in the volume of the media since they were set up. The problem is at times seen on all the channels or in some channels while the other channels are just fine.
 I was wondering if anyone experienced in working with this instrument has encountered any similar problem and would appreciate any assistance or direction to resolve this issue.
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Thank you so much Filipa. I have tried the greasing option. Am presently checking for mycoplasma. But, I haven't checked the first option. I will definitely give it a go. Thanks a lot.
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I am trying to design the best patient monitoring system based embedded system.
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Its hard to advise without further information, but for general Micro-controller applications Atmels AVR-8 series of controllers is great (eg. ATMEGA168) . (I would recommend using an old version of AVR studio as the latest ones are somewhat over complicated).
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I'm not very tech-savy when it comes to cameras, so I'm not sure how "cheap" I can go with a camera and still get good motion tracking results. What are the important specs in commercial cameras / webcams? Or, alternatively, is there a dedicated source of motion-tracking specialized cameras that I don't know about (and that aren't incredibly expensive)? 
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NAC has a $10k system (analysis software and everything). That's about as cheap as it gets in the industry. I've used it for high speed locomotion and it works fine; but you're probably filming events that are slow enough not to need high frame rates. You can get 30 fps with any standard DSLR camera or iPhone 5 and above (that's when there was a major camera upgrade), and I know there are some simple apps for motion tracking. Lastly, can't go wrong with GoPros: they're cheap, durable, and can do quite a bit. If you're looking to go the 'layman's' route, check out Ty Hedrik's (UNC chapel hill) software for motion tracking.  
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oes anybody have experience to share about Biotek microplate readers?
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Hi Alejandro,
I have now used plate readers from 3 different companies. Gen5 software is by far my favorite and is, in my opinion, the most user-friendly of them all (Biotek, Molecular Devices, Promega). The instant-output to Excel is fantastic.
Looking at the spec sheet it looks like the H1MF is the current model equivalent of the Synergy H4 that I used previously. This was a an excellent instrument that was highly flexible for the various assays that I ran. I used the instrument for fluorescence, fluorescence timecourse, absorbance, absorbance timecourse and luminescence very frequently. My favorite features were (1) the monochrometer, allowing you to dial in the exact wavelength you want for absorbance and fluorescence, with the available filters for standard wavelengths and (2) the spectral scanning ability. The filters will be more sensitive, but the flexibility of the monochrometers is unbeatable. The spectral scanning was helpful validating FRET experiments as well as characterizing some of the new chemicals we were developing.
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My lab will continuously processing a low volume of tissue samples. We want something relatively small, easy to clean up and maintain and preferably something that can sit on a bench top. Any recommendations? 
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We have found the Mini-Bead beater to be one of the most useful items in our lab. It has a very small footprint and can homogenize practically any type of tissue you come across, from single cells and bacteria to the really hard FFPE items. In addition it helps cut down on cross contamination, since tissues/cells are processed in a single  vial.
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how do you convert an ADC digitized numeric value (0...255 for 8 bit) to a voltage, i.e. how do you figure out what voltage does this number represents ?
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For an 8-bit ADC with 0-5V input range, each bit results into 19.48mV or roughly 20mV.
Therefore, in your software you can simply multiply this number 20 (or 19.48 to be precise) to get the voltage reading.
Hope this satisfies your requirement.
Thanks and best luck!
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I need to compare some statistical parameters of PPg signal for different age group.
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Hello. I need a new fume hood for the laboratory and I have two options to choose: Labtech LFH-150 or Biobase FH1500. Could you tell me any experience using any of them? Thank you.
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Hello Miguel,
Merry Christmas and Happy New Year!
While selecting the fume-hoods pay attention to every details on the specifications and accessories rather than the price tag. I have a good experience earlier that one particular product was with the necessary filters but eventually was costing more. Other vendor only quoted the fume-hood without filter and since the price was lower then the one without a proper filter was ordered.
As far as specifications are considered, first check what BSL (1,2,3 or 4 level) your lab is. Then pay attention to the regulatory and conformity standard your particular equipment is designed and certified for.
Coming back to the two specific products you have stated,  - one is with simpler analog control(Labtech)  while the other (Biobase) comes with digital control and filter life-time alarm/warning. Eventually, the cost would be different and the later would be comparatively costlier than the first. Besides the cost difference, pay attention to the service support and original warranty that a manufacturer provides for the product. Also, the filters are consumables and sold separately, therefore pay attention to keep a few in stock with you. This would depend on how frequently you are using your fume-hood. If needed daily, the filter replacement life-time and the total cost would be factor to seriously think about.
It is my experience that we start with procuring many times sophisticated products just to show our lab(s) are modern and high-tech but later end up in abandoning these costlier investments simply because there was no maintenance or availability of spare parts and service support. Therefore we should be mindful or proper returns on our investments.
As far as the fume-hoods are considered, proper air suction and vents are more important rather than how you control the speed of the suction fan and durability and life-time of the filters. Keep close look at these primary factors and then decide what best suits your needs and more importantly your budget and available funding!
Best wishes!!!
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I am looking for a wideband powerful monolayer LED in order to substitute the filament lamp in a microscope, any suggestions? Thank you.
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None of the commonly available LED sources do a very good job approximating the spectral radiance exitance of a incandescent filament lamp.  CRI is a test of how close the color of a set of moderate chroma painted papers appear compared to some standard conditions (either natural daylight or an incandescent lamp).  You can place the lamp into a fixture along with the incandescent lamp and you will often see that the lights are not visually identical.  One classic issue which may impact your use is that the LED white is generally deficient in red energy while the incandescent is quite rich.  Thus natural objects with a  violet, deep red or magenta appearance will appear as blue, dark gray or dark cyan under a standard LED.  Thus I agree with the recommendation to avoid the Blue+Yellow phosphor lamps and go with a 3 or 4 LED lamp.
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I want to know the instrumentation facilities for cardiac pressure and haemodynamic analysis for rats in chennai or any part of Tamilnadu.
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dear Sir, please follow the link below and i believe you may get some details you are looking for. thanks.
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Which force is needed to make an implant move/grow through soft tissue? There seems to be a threshold to be overcome by stents (or other implants) to make them grow through tissue. Too low means no growing through. Too high would create lesions. The only reported force I know is from bracelets on the teeth (nearly constant 1-2 N for extraction).
Is there anything known for soft tissue? Ideally for stents in atrial walls? Which biological processes enable this kind of "growing through"? How could i foster it?
I'd be thrilled to hear about your input!
Johannes
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Conventional arterial stents are designed not to grow into the intimal, medial or the adventitial layers. The stent is designed to distribute a uniform radial force sufficient to hold it in place reliably. Restenosis is and undesirable consequence that presents as a growth around the stent. If you want a stent to 'migrate' through the artery wall then it must be designed for that purpose. The form factor and profile for each strut should be reconsidered. Other considerations would be the edge effect of outward radial forces and perhaps other means of constricting the artery to provide a reactive force. These can be mechanically or pharmaceuticaly induced.
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In previous there are many way to measuring biological information with and without driver knowledge but in my research i am used mixed signal processor and motion level detector and biological information sensors,and driver activity monitoring sensors are used to detect and find vehicle and driver activity for reference.So i want know how to interface these are the components without driver awareness biological information measurements?
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Hello Gobi,
I'm not sure if this is what you are looking for but I think that you could use only video to monitor both driver activity and biological information. For the latter I suggest using eulerian video magnification to get basic biological parameters such as pulse and breathing rate.
Hope it helps,
Jaime Yagüe
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I am working with cut and coagulation signals produced using electrosurgical units applied in organic tissue.
I am looking for database for these kind of signals produced by commercial units (electrosurgical devices). Could someone, please,
suggest an internet database? Thanks in advance.
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I worked repairing and designing electrosurgical devices some years ago and yes, but it is not exatly  in a database. All models of electrosurgical units have their own power curves. The only way to find them is un the technical manuals of Ellman, Bovie, Valleylab, etc. 
Maybe this boom could be helpful form you
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as we know the bypass sugery cost much... one of the reason of that is everytime sugrery is done we have to change the oxygenator... so if can sterlize that oxygenator that can reduce the cost of surgery
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its possible to sterilize oxygenator since it has been followed by many of the hospitals
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We are treating A549 cells with pulsed electric fields.  The media becomes more redish after prolonged treatments (11 hours).  When the cells are returned to the incubator overnight, the PH changes back to its 'normal' look (less red).  Is it possible the electric fields are changing the PH of the media during our experiments? Or perhaps just having them out of the incubator would cause the media to turn more redish? The media has phenol red in it.
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I am not sure if the electric field has effect on PH. But if you consider that PH is actually the availability of the H+ ions its safe to assume that there would be certain effect from the electric fields. 
but more importantly there is constant supply of C02 in the incubator that also acts like a buffer and maintain PH, unless you are using a different buffering approach than the carbonate buffering system. 
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Does anybody still use old-school electrooculography (EOG) outside the sleep lab and has experience with the type of electrodes to use? We are starting a project with mobile EOG and used ECG electrodes (which are too large and induce considerable drift over time). Since we are interested in the short-term change of the signal (aka scanpath behavior), it is quite important that the drift is minimal...
So again: Which electrodes are best?
Greetings, David
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In my many field studies I have used Ag/Ag-Cl cup electrodes affixed carefully with collodion.  For example, TECHNOMED Cup Electrodes with Silver/Silver Chloride Plated Disc (TE-C22), viewable at http://kingmedical.com/neurology-diagnostics/eeg-supplies/reusable-eeg-electrodes/technomed-cup-electrodes-with-silver-plated-discs-430.html.  With practice, you can get an electrode placement like this to last more than 24 hours, given not too much sweating.
Make sure that the subject's head is turned such that liquid would roll away from the eye.  Be gentle with skin cleaning before electrode application -- this is a skin area that marks easily.  Also, cleaning so much that the electrode connects with body fluid makes the body an antenna for ambient electrical noise.  Just swab gently with alcohol on a cotton pad to remove surface oil.  For electrode removal, I soften the collodion with non-acetone nail polish remover on cotton, holdng the moist cotton gently against the electrode.  Then pull the electrode off gently.
You don't have to be super-close to the eye.  Recall that the Rechtschaffen and Kales standard indicates about 1 cm from the outer canthus.
The Ag/Ag-Cl electrodes will allow you to pick up  slow eye movements, including the slow, rolling eye movements associated with Stage 1 drowsiness, as well as saccades and pursuit.  Of course, you won't get all the way down to DC or get good absolute angle values, as you would with an eye tracker.
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Peltier element is widely used in different instruments especially in biomedical insruments. I want to check the resistance of it. How can I do that?
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The measurement method will depend on what you are trying to do.
Most Peltier devices are semi-conductors, and so the resistance changes with temperature and to some extend applied voltage. If you are trying to build a device using a Peltier module and you need to understand the power consumption, then you need to operate the device close to the operating conditions, in terms of hot and cold temperatures and heat flow. Then measure the current through the device and divide this into the voltage across it. This will give you the resistance at the operating condition. You can then change the operating condition and measure again.
Best Regards
Paul
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I need clear each and everything about instrumentation setup from basic alignment  to final calibration of pump-prob spectrometer. I need all laser systems functional procedure and what are the safety measures to be taken and consider while in this experimental arrangements? Give some basics to advance ideas to setup this facility. Each and every aspects of ideas will be appreciated and make an excellent setup to be utilized many researchers  for their research works.
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Is it possible to give some more detailed information on the samples you are interessted in. Because there are so many different laser-detector systems combinations possible without a deeper insight what you are trying to achieve.
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Hello Every one,
I am working on pretreatment of lignocellulosic biomass, I am facing a problem while preparing a smear for SEM analysis of pretreated sawdust.  please let me know the  smear preparation in-detail and suggest me one of the best methods.
Thanking you All.
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Easiest way (may work for you): put sticky carbon tape on specimen stub, press it in sawdust, knock out excess of the dust (with hard knocks on a table), apply conductive coating, put it in SEM.
Sawdust should be dry; if needed let it air dry for a while.
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I want to build this device, but I wonder if anyone has a schematic or PCB design of this system.
Preferably without using piezoelectric sensors.
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Mr. Moradi,
Your question sounds like you wish to undertake invasive heart rate monitoring as opposed to non-invasive methods performed routinely by most modern blood pressure monitors you can purchase from pharmacies.  Perhaps if you state the purpose of your design then you might receive many more responses in addition to the very good ones you have had, all of which are suited for application in non-invasive monitoring.
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Though many research groups are active in making this device from so many years, why nobody has come up yet with a great accuracy? I know calibration is one of the toughest parts.
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The following article discusses the issue:
Accuracy of the Non-Invasive Glucose Monitoring Device Pendra® compared to Alternate Site Glucose  Measurements at the Lower Forearm during Dynamic Blood Glucose Changes in Type 1 by  Forst et al.
See the full article at the link:
Abstract::
The use of alternative methods for glucose monitoring in diabetes mellitus
receive increasing attention. The new developed impedance spectroscopy based
Pendra® allows continuous monitoring of glucose variations at the lower forearm
in a completely non invasive approach. However, recent studies with various
invasive methods revealed some discrepancies in blood glucose readings at the
lower forearm compared with the fingertip, especially during rapid glucose
changes.
In our investigation, glucose readings obtained from the lower forearm using
Pendra® and an alternate site technique (AST) were compared with blood glucose
measurements obtained from the fingertip during a standardized glucose
challenge experiment in 12 type 1 diabetic patients (5 female, 7 male, age:
31.5±8.7 years). Patients ingested 75 g of liquid glucose and after 2 hours, insulin
was applied intravenously or subcutaneously in a randomized sequence to
achieve a rapid or modest blood glucose decline. Blood glucose was measured
every 15 min and compared with reference glucose measurements (glucose
oxidase; Super GL) obtained from the fingertip.
During increasing blood glucose values, no significant differences in blood
glucose measurements could be observed between the different methods or skin
locations. During both, rapid and modest blood glucose declines a significant time
shift in glucose measurements could be observed with the AST (p<0.001,
respectively). No systematic differences could be observed between Pendra®
measurements and the reference values obtained from the fingertip. Error grid
analysis according to Parkes et al. of both glucose monitoring systems is given in
table 1.
Glucose measurements at the lower forearm using Pendra® do not reveal a
systematic shift as already described for AST measurements. During rapid blood
glucose changes, induced by intravenous insulin application, the precision of both
blood glucose self monitoring methods showed a slight deterioration in precision
evaluated by error grid analysis.
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Like many labs we are trying to stretch our budget. We've been growing  primary neurons in a shared incubator, but now need to purchase our own. 
From a microbiological point of view is this a bad idea?
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Thanks for your advice!
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I am interested in studying the natural mechanisms that change the appearance of the prostate under conditions of high pressure including herniation through the bladder neck and anteroposterior axis elongation.
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There is an ultrasound technique called shear-wave elastography (SWE) performed by means of transrectal ultrasound. It can quantify the pressures and show color scale together with accurate measurement of pressure. There is only one ultrasound machine capable of SWE, its is Aixplorer, manufactured actually by French company, Supersonic Imagine, Aix-en-Provence.
Best PM.
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Shall I try to tighten the screws around the hydraulic system or call the technician?
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From your (very cryptic) description I deduce that it must be a hydraulic press. Probably a seal has worn out. If you indeed have a service technician at hand there, then call him/her in. Usually seals are well replaceable (if you can find the right partnumber).
Future hint: It helps if you state the brand and model of a defect device when asking for tips.
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I want to construct new lab in neurodegeneration using transgenic animals and cell lines and I need to know the most important for the studies such as fluorescence and other main used devices.
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We study neurodegeneration (MS & Stroke) both In Vivo & Vitro.  It all depend on which disease you will study but you need a cell culture unit and an animal care facility.  We highly depend on a Bio-PleX (Luminex) system, a QPCR system and a FACS.  For imaging, a fluorescent and confocal microscope.  Capability for behavioural studies (as above) & immunohistochemistry which includes a freezing microtome and a cryostat.
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Lps fbs free
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It depends on your experiment. For secretion of cytokines and measurement by Western, LPS stimulation is generally performed in serum-free medium to prevent overloading of of a gel or clogging a NMWC filter. For ICC, ELISA or PCR, serum can be maintained at normal concentrations.
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I want to preprocess EEG signal using ICA algorithm.
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I have a recent research paper Alireza, which may be of your interest. Please see the attachment.
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I am trying to find a way to mathematically calculate the cardiac output (CO) and stroke volume (SV) from vital sign parameters such as arterial blood pressure (ABP), end tidal CO2 (etCO2), ECG, heart rate (HR), pulse oximetry (SpO2), and non-invasive blood pressure (NIBP).
Are there any mathematical formulas that can provide CO and SV from vital signs monitoring parameters? I'm trying to compare the results from a commercial-based hemodynamic device and mathematically calculated results using vital sign parameters from a patient monitoring device in the OR.
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Hello Loek,
That is what I am trying to find. We have patient who are under sedation but we donot have invasive arterial line to monitor CO and or SV in such patient. Without using any non-invasive hemodynamic monitoring system. Is it possible by analyzing and the Physiological parameters such as Spo2, RR, ECG, NIBP, Etco2 etc one would hopefully be possible to provide a rough estimate of CO and SV within some error range?
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Does anyone know of an IV Infusion Pump that is FDA approved and has the ability to access the communication port to perform Closed Loop control system for clinical research purposes?
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Hello Jayaraman,
Thank you for responding to my request. Currently we are looking for FDA accredited LVP (Large Volume Infusion Pumps) peristaltic pumps as well as syringe driven infusion pumps only. Unfortunately FDA accredited pumps are what we can only work on.
The Alaris Medical new generations pumps such as the Alaris Medley and the Smith-Medical Medfusion 3500 for the syringe based pumps would be of an interest. This is ofcourse for pure clinical research purposes.
Anyone who might have had experience in re-engineering for the purpose of data communication interface to these pumps, please do contact me.
Thank you,
Best regards
Tim
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If you are looking for FTIR. Thermo Scientific produces very reliable ones.
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I would like to develop an electrical bio-impedance based cancer diagnosis system, but I have a doubt that which excitation approach is better. Does anyone has any idea on this? Thanks in advance.
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There is no unique answer to this question. Some factors to consider:
- In-vivo vs. in-vitro measurements: In-vivo measurements are limited by the maximal acceptable auxiliary current through the patient according to accepted standards. In-vitro measurements are limited by non-linear phenomena in electrodes because of excessive current density.
- Value of the electrical impedance to be measured: Current injection is limited by voltage compliance of the electronic circuits hence maximal acceptable currents for large impedances can be very small and any leakage current because of stray capacitance to the environment becomes very important.
- Frequency range: parasitic capacitances in electronic circuits make it very difficult to achieve an “ideal” current source through the sample under test.
- In-house expertise: good voltage sources are readily available whereas designing a good current source takes some expertise in analog circuit design at the system-on-board level. If you apply a constant voltage and measure the current through the sample, you avoid the design of current sources.
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At the moment I am trying to start a protocol involving cannulas implantation in specific regions of rat and mouse brains, and for that I will need to buy a stereotaxic instrument. I found a lot of alternative companies to buy from but I am particularly focused on two of them. If anyone can give me feedback about the instruments from Stoelting and World Precision that would be really good.
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I would go for a single arm and no electronics attached. Those are not really helpful to correct your coordinates but just help in doing the surgery more visual and sometimes fast (in case of the display showing axis movements). I would ask for quotes to Stoelting or Kopf (I don't know WPI frames but they may be good as well). I used both of them. I recommend to check also the pricing infos for add ons for any of the frames you are considering, in advance so you know how much it would cost for you to upgrade the instrument. I was using a kopf for cannula implantation. You eventually need a cannula-holder to place the cannulas on the skull. Which could be an additional 250 euros, or something similar (if you are in Portugal).
Stoelting has the same tool and WPI as well... In my opinion KOPF looks more well made, robust and stable... But I don't want to make bad advertising...it could be just due to different lab usage.
Regarding the add-ons, If you don't need to use strange angles but you will do always orthogonal injections - as for cannula implantation - you can even think of buying just rat earbars (they can be used for both rats and mice), so it would be cheaper. If you use mice, you will need a mouse jaw holder (if not included), which is different from the one made for rats of course (is basically the steel support to keep the jaw closed). If you need to move around (also changing angles) maybe the "small animal holder" (to understand, this would be the black steel support on the stoelting website, it comes with smaller earbars and smaller jaw holder) is more useful because it has finer regulation for the height of earbars and jaw holder. In addition, due to the more advanced position in respect to the holder/cannula/pipette support, it allows a wider range of angles and movements (but of course is more expensive). So it depends what you plan to do.
I would avoid electronic assisted frames simply because:
1) if there is an issue you have to call the company and the instrument can't be used (with the basic steel frame this rarely occurs, unless it drops on the floor)
2) if you misplace the skull the system doesn't correct for that so eventually is not really helping in precision. Plus, if you know where to inject, you probably have already a brain atlas you have consulted before doing surgery (so you don't need a live update with computer screen and software for that, it is just costly).
3) the only electronic device (if you have the money) I would reccommend is the digital display that shows you the movement update on each axis (this saves you time looking for the right coordinates on the metric scales on the frame arms and allows precision and consistency.
so my suggestion would be
frame #900 single manipulator, 100 micron (page6)
animal adaptor (page 16) model # 926
cannula holder 1776 P1 (page20) if fits with your cannulas
earbars #857 for rats (adaptable on mice) (page 19)
but you can compare the pricing from Stoelting and decide based on the difference
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To find an alternate for brain's frequency following response
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Brain wave entrainment and modulation
can be achieved using forms of transcranial electrical stimulation, deep brain stimulation, light stimulation,, and other. Inputs. depending on brain. state.
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Please give the details characteristics of X rays.
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Hey Sabari. X-Rays are electromagnetic radiation whose wavelength are between 0.01 to 10 nanometers with energies between 100 eV to 100 keV. Could you elaborate on what you mean by characteristics of X-rays? What does QA stand for?
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Suggestions needed regarding some previous works done in the field of measuring mechanical properties of human brain cortex tissue.
Also the response to stress, strain, compression force that any electrode implanted in the cortex in the top 5-6 mm range will experience.
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Dear Sanchit
Giulia Franceschini
THE MECHANICS OF HUMAN BRAIN TISSUE
UNIVERSITY OF TRENTO
Modelling, Preservation and Control of Materials and Structure
Tutor: Prof. Davide Bigoni Co-tutor: Prof. Gerhard A. Holzapfel
Trento, febbraio 200
Below the conclusions of this thesis:
Brain tissue have been found to present distinctive mechanical properties, making them qualitatively similar to filled elastomers under cyclic uniaxial stress and to fine soils obeying consolidation theory under oedometric conditions. However, unlike soils and again similarly to elastomers, the ratio between initial oedometric modulus and initial elastic modulus is large. Our results suggest that mechanical modeling of brain tissue should involve a porosity model to account for the intrinsic porosity of the brain matter, at least in situations where substantial volumetric deformations are involved (during for instance hydrocephalus). Moreover, the drained behavior of brain parenchyma should be treated as a nearly incompressible, nonlinear material, capable of permanent deformations and qualitatively similar to rubber-like materials. Although in the present thesis we did not attempt to develop a constitutive model for the description of the mechanical behaviour of brain tissue under arbitrary deformations, we have shown that this model should reduce to Terzaghi theory, when small deformations occur due to the consolidation, and to a theory describing nearly incompressible rubber-like materials, when large deviatoric deformation are involved
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From 2-01-2014 onwords the DDSM Mammography link page http://marathon.csee.usf.edu/Mammography/Database.html is not opening. I couldn't even open the thumbnails. Can any one help in this regard?
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Ping thier server first, if no response contact their system administrator, authors listed in some papers referring to it. Check if there are some mirror servers ?
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I'm trying to monitor oocyte and embryo vitrification process using a tiny micro-camera which requires at least x400 augments. Have you any recommendation?
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I am currently studying gait and posture analysis. What are the factors that you need to consider while dealing with pressure sensors? (Example: type of sensors used in force platforms)
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Anvita! When selecting any sensor you have to consider the following: time response, range, non-linearity, drift, accuracy, repeatability, among other factors. Our experience with Force Sensing Resistors (FSR) proved to be very effective for Plantar Pressures though we did have to improvise certain augmentations to the structure of the sensor and the method of sensor calibration. You may look at some of our articles for further clarifications.
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Diaphragm pumps are used in surgery with water.
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I typed "pump diaphragm material" into the Google search box. Got lots of hits (of course) but the commercial site below covers 14 pump diaphragm materials.
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Most of the biopotentials are less than 30Hz, others are so low as almost 1Hz....
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One of the most critical measures in the ECG is the ST segment, often a flat line between the end of the QRS and beginning of the T wave. Such changes indicate significant ischemia or even an ongoing infarction. Changes are often seen as a DC shift (elevation or depression), hence a very low frequency change which the instrumentation must be able to measure. The lowest heart rate one might see is 30 beats/min or .5 Hz. Recognizing that the phase response of a filter is at 50% of its maximum at the corner frequency and that phase shifts would have the most significant impact on the ST segment, it has been the standard to use one decade lower for the ECG high pass corner frequency, or .05 Hz.
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I have two Ag/AgCl electrodes and a circuit to obtain SCL signal. While doing experiments I observed that when I left electrodes open and used two fingers and touched on two electrodes, it took a period of time for SCL signal to rise a stable value (let's call it rising time). The curve is similar to the capacitor voltage vs. time in RC circuit. When I used the inner side of a palm to touch on these two electrodes it took much longer time to rise to a stable level. During the experiments, there was no stimulus hence, the rising time was not the 1-3s rise time of SCL signal after the appearance of a stimulus. I think it's because of the capacitance of the skin. However, I am not sure which part of the finger or palm (skin or inner tissues) causes that. Is the simplified equivalent circuit of the electrodermal system explained in http://www.bem.fi/book/27/27.htm sufficient enough?
Could anyone help me to answer this question?
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It may be enough depending on your application. It is proved that the conductance of the electrode-skin interface increase with the time because the semi-empty pores of the skin star to fill up with electrolytes. Those electrolytes could be the conductive gel of the electrodes or secretions of the body. take a look in the article "SYSTEMIC AND RANDOM VARIATIONS OF ECG ELECTRODE SYSTEM IMPEDANCE" from J. Almasi
Also, if you apply a electric stimulus for long periors (like you mention 1-3s) the electro-osmotic effect can take place. Therefore you should include a memory-element into your model. For this take a look into "Skin impedance and electro-osmosis in the human epidermis" from S. Grimnes
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I would like to distinguish muscle from tendons when imaging foot, ankel, or limbs with x-ray CT system.
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thank you so much for your comments. I will definitely look into those references. I appreciate your time and help very mcuh!
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What is the typical threshold for tetanic contraction and how much variability might there be in humans? Is there a relationship between fatigue and frequency? When would higher frequencies be needed (e.g. to overcome some degree of axonal degeneration as a result of a nerve electrode implantation)?
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The relationship between frequency of stimulation and motor function depends on the muscle being stimulated. If a muscle is predominantly slow twitch (for eg., muscles that generate a low amount of force for prolonged periods -- tonic activity) the frequency required to reach tetanus will be lower, typically below 15 Hz. If the muscle has predominantly fast twitch motor units (eg. muscles that generate a lot of force for a brief time -- phasic activity), the frequency required to reach tetanus will be higher (typically 30 Hz and above). By definition, predominantly slow-twitch muscles are more fatigue resistant than their fast twitch counterparts. Also note that skeletal muscles are very plastic and may change from predominantly fast type to slow type if their loading conditions demand it. In the particular context of FES, the faster motor units are recruited first in a fresh muscle (unlike the size principle). As for axonal degeneration, I would think more current would be needed to recruit the muscle rather than the frequency.
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I am looking for an effective, non-invasive instrument.
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I knew about a work where the evaluators used accelerometers and gyroscopes to see the development of parkinson disease; another, but not easy for this cases is fMRI...