Transducers - Science topic

I had a miscommunication with a coworker, and as a result I put unfiltered virus harvested from 293T Phoenix media on to my primary fibroblasts. The transduction worked well, but now I have a couple contaminant Phoenix cells on my culture dishes.

I have tried several days of aggressive washing, since the Phoenix cells are easily detached, but that has been unsuccessful so far at removing all of them. The primary cells I have successfully transduced are very precious, so any other ideas at removing the Phoenix cells are appreciated.

As a last resort, I can flow sort the cells into single wells and grow them out from there. Hoping to avoid it for now as it is incredibly time consuming and also stresses out the cells.

I'm looking for some cell lines that AAV9 will transduce efficiently at 10^6 MOI besides CHO-Lec2. I've already tested CHO-Lec2 and found decent transduction levels (~20%). But now, I would like to gather additional data in other cell lines. Any suggestions? I've heard maybe U87 cells are good for AAV9? Let me know your thoughts, thank you!

What is the best cell line for Cardiomyocytes for in vitro functional assay. I need a robust cell line easy to transduce and maintenance.

I have several candidate to consider:

C21C2, AC16, and Human Cardiac Myocytes (HCM) and iPSC-cardiomyocytes

Could you please let me know if you have any experiences working with these lines and if you have any suggestion or reference for me?

Thank you!

If I want to transduce cells with two lentiviral vectors, do I perform the transduction one after the other? Or do I collect the lentivirus from the different HEK plates and co-transduce my target cells?

The stainless steel bolt destroyed my front mass(AL7075) threads ☹️ any advice?

this is for an ultrasonic transducer

I am expressing two genes (CAR and a reporter) under EF-1a promoter in a lentiviral vector. I am using 2nd-generation lentiviral system (psPAX2 and VSV-G). My transfection efficiency in 293LTV cells was more than 99%. I collected the virus-containing supernatant, concentrated and then used it to transduce Jurkat cells. Unfortunately, my transduction efficiency has not exceeded 10% with MOI=10.

Here is my transduction in detail:

Polybrene (8 µg/ml)

Cells were washed once with PBS and then resuspended in base RPMI (FBS=0%)

Spinoculation (2400rmp, 2h, 32 °C)

The media was changed after spinoculation

The expression was checked 72h post-transduction.

I also tried higher MOI (20, 50, 100), but the expression decreased.

I appreciate any help.

Dear research community,

We have tried multiple times to transduce E0771 breast cancer cells with viruses to make these cells fluorescent or express luciferase. We have been very unsuccessful. If any of you has these cells transduced with RFP and/or luciferase vectors and is willing to share them with us, please reply back. We'll be more than happy to pay for shipping costs. Thanks to all!

I have infected iPSCs with a lentivirus and sorted GFP positive cells. But after just a few rounds I am finding cells without GFP in culture. Had anyone seen this? Maybe cells are segregating inserts into only one of the cells after division? I think that this could be the problem, but never saw this before.

Let us consider that we are using an underwater acoustic transducer Model 630 in an underwater AUV application. Usually in the data sheets, the manufacturer provides the details of operating frequency, input poser, operational depth, typical receive response, and transmit response. Suppose I want to calculate the typical receive and transmit responses, then what formula is to be used?

Hello everyone, please I am trying to transduce my suspension cells, I don't know if the transduction is successful so as to continue with the puromycin selection, please I will appreciate your kind response to this. Thanks

Hi ,

I have been trying to transduce my iPSCs with sgRNA , at MOI 5 and 10 and I have had very less efficiency . (3-4%)

My Lentiviral supernatant is concentrated.

Could some one provide some insight on the transduction process?

Thank you

I am currently performing DNA extraction for a transduced cell with a virus but whenever I perform PCR, there is presence of viral DNA in it. So may I know if adding DNase into the cell before extraction and performing washes will eventually eliminate viral DNA and not the transduced cell DNA?

I would like to use puromycin selection in mouse primary cortical neurons to select for transduced neurons. Have anyone had any success doing it?

I'm confused about 'homogeneity of cellular transduction' of AAV. Does this mean AAV can only transduce one certain type of cells after it enters into living organism?

It seems to me that everyone just refers to J. W. Goodman's book "Speckle phenomena in optics: Theory and Applications". I agree this is a good book, however in my opinion there are some differences in ultrasound.

I would like to find answers to the questions:

- how realistic is it to assume that the ultrasound signal has a single spectral component (monochromatic light assumption in Goodman)? Is this assumption required?

- what is the effect of ultrasound transducer and the transformation from pressure to RF signal?

Thank you for your answers.

Is it possible to transduce a human CAR into mouse T cells and have the mouse T cells function when the CAR binds it's antigen? I am thinking that if anything the singling domain of the CAR, as it is human, may be a problem for the mouse T cells.

I am designing an inverter circuit to produce 20khz, high current and high voltage power for an ultrasonic transducer.

I want to know what are the parameters in choosing a mosfet for my application?

can anyone help to me and explain in more details

I transduces mesenchymal stem cell with lentiviruse but it is not efficient...

/5 ml of concentrated lentivirus was added to each well of 6 well plat with approximately 100/000 mesenchymal stem cell and poroumycine selection was perfomed after 4 days, but was not efficient. it is important that concentrated lentivirus mixed to fbs free medium? I mix it to fbs+ medium and added to cells drop by drop

How to calculate the amount of pressure generated by the ultrasonic transducer (single element or multi-phased transducer) after applying a certain voltage to it? I want to use this pressure field as the initial condition for longitudinal wave propagation simulation.

I transduced my B cells with GFP containing plasmids using lentivirus and achieved 60% positivity. However, when I checked my cells under the confocal microscope, I can not see any GFP signals. (Maybe a little bit, but the signal it gave is similar to the signal given by non-transduced B cells). I was wondering does anyone know what could happened?

I am titrating lentivirus using Jurkat Cells. I transduced 250,000 cells with .05ul/.00005ml of undiluted virus in 1ml of RPMI media. We analyzed the fluorescence using Flow after 72 hrs (13.29%).

Which formula should I use?

Formula 1: (Number of cells transduced on day 1 x Percent fluorescent)/(Virus volume in mL)

Formula 2: ((Number of cells transduced on day 1) x (Percent fluorescent/100))/(Volume of undiluted virus Added (ml))

With formula 1, the titered amount will be: 664.5 X 10^8 TU/ml

With formula 2, the titered amount will be: 6.645 X 10^8 TU/ml

Formula 1 does give a huge titration number, but this is the formula I have found online everywhere.

Does this concentrated virus make sense?

Dear researchers,

My research area is related to the development of metallic composites. I am switching to sensor development. Basically, I will work on the development of advanced materials for sensor applications. I need your guidance, suggestions, and ideas. I am also looking for collaboration in this area.

Looking for your valuable replies.

Hi all, I wonder how it works in a Cre-dependent system when you use much less titer of Cre virus. Let's say we use titer 1 for virus A, and we use titer 1/10^3 for Cre. In ideal cases, we transduce X cells with A but only X/10^3 cells express due to Cre. But would it also be possible that there is less amount of Cre transducing each cell (resulting in the total transduced cell number > X/10^3) instead of the expected amount of Cre transducing fewer cells (resulting in the total transduced cell number =X/10^3)? If latter, would there be a difference between cell expression levels?

Does anyone have a working protocol or suggestion for CRISPR knockout gene in THP-1 cell. I worked for more than half year to knock CFB gene in THP-1 cells. When I transduced the CAS9 into THP-1 at the beginning, after I applied blasticidin 99% cells died, very small portion of cells didn't proliferate, and finally all cells died. I got CAS9 expressing THP-1 cell at the third try. But I still cannot get single cell clone by limited dilution. Because the single cell didn't proliferate, all the cells died later.

It was even exceedingly difficult to transduce the guide RNA into the CAS9 expressing THP-1 cells. I tried twice, all the cells died after apply the selection antibiotics hygromycin. The transduced cells even died faster than the untransduced cells.

Any suggest and help are welcome.

I'm trying to analyze bolted joints using PZT transducers. But "The electric potential will not be constrained for contact pair" warning is altering the results. How to overcome this warning?

A horn antenna, usually used in connection with the UHF and microwave frequency range, is a transducer which operates on the same principle as the acoustical horn. Can we connect such antennae with the 377 Ohms that is identified with the impedance of free space?

Hi all, I am working with H4 cells that I have transduced with an engineered construct for a transmembrane receptor with a tag on it. I have detected the construct with immunocytochemistry and I would like to detect it via Western blot as well. I am using a different purified protein with the same tag as a positive control and have had no issues detecting it. However, I can't seem to find my target protein in my H4 cell lysate samples, and I am worried that the protein may be getting stuck with the debris pellets during my lysate preparation.

I am preparing my lysates with NP-40 lysis buffer, boiling my samples at 100C for 5 minutes before loading into the (4-20% gradient) gel, and have been transferring onto nitrocellulose overnight at 30V (at 4C).

Could you please say what would be the maximum output voltage obtained from the individual sources i.e., from piezoelectric transducer and electromagnetic converter

The ultrasonic machine preferred is5Mhz capacity . The specimen used is Fiber metal laminate. Transducers using are Apprx.1 inch, so maintaining a focal length of 25.4mm between the specimen and the transducer. while performing through transmission pulse mode ,I have observed the echo transmission in the ominiscan are yellow in color, After placing the specimen the yellow color echo transmission are converted to green color. i have varied the Gain in the UT setting and threshold was set to 90%. even though green echo transmission are appeared on the screen . Also i am not able to capture the damage area of the specimen . The obtained image is attached .will any body help in resolving the problem i am facing to get the out put.

Do we need a smoother thin film of Piezoelectric membrane material in the PMUT device performance? is there any dependence of resonant frequency on the roughness of piezoelectric membrane in PMUT?

I'm trying to make a stable HEK293T cell line that expresses GFP only in the presence of a specific unnatural amino acid (UAA). I packaged lentivirus particles containing my expression cassette, transduced cells, and selected for puromycin and blasticidin resistant cells (used two lentiviral constructs). Using 5 µg/mL puromycin and 6 µg/mL blasticidin, non-transduced cells were killed by 48 hours, while transduced cells remained viable. I expanded these cells and passaged 2x before assaying.

To validate my transduction, I set up an experiment in which I treat cells with or without a UAA and monitor GFP expression (which should only occur in the presence of UAA). When I perform this experiment, I observe that almost all cells are GFP-. Even more perplexing is that ~1% of cells are GFP+, but this phenotype is independent of the presence of a UAA (GFP+ cells without the addition of a UAA). I have attached microscopy images illustrating this issue.

- My expression vector was constructed such that the UAA utilization genes are expressed on the same mRNA as the puromycin resistance gene, separated by an IRES.

- When I transfect my GFP/UAA utilization plasmids into HEK293T cells, they work as they should. This issue appears to be transduction-related.

I am looking for a technical guide for ultrasonic homogenizer design and manufacture.

I need a detailed explanation about how to design a transducer, booster and horn system for homogenizing solutions.

I would appreciate if you could please send me such a file or link.

I want to compare impedance analyzer results with FEM ones.

I want to build a 100W 20khz ultrasonic transducer.

where or how can I find the dimensions?

my pizeo stack dimensions are: 50 17 6.5 mm

Can anyone point towards a tutorial or video where I can perform co-localization analysis using ImageJ? I have a very simple experiment where I have stained HEPG2 cells with DAPI in order to count the number of cells and I have transduced a vector expressing GFP. I really just need to know the number of cells that are green in a given image. What would be the best way to do this?

We are trying to do some slice cultures and we need an established protocol for cultures. Also how transduce the slices with AAVs ?

I am using lentivirus system to transduce my transgene in T cells. but I observed transduction efficiency goes down over the day in T cells. While The gene is stably expressing in HEK293.

Can anyone help please??

I need to design and simulate a power supply(generator) to drive 6 transducers. power of each transducer is 50 watts and they work at 40khz frequency.

can you please share a design of such generator with me?

I am developing stably transduced HEK293T cells (lentivirus) with constitutively active RhoA gtpase. I have no experience in Microscopy and I want to characterize these cells visually and expand them prior to western analysis. I see this round morphology, but i am unsure if this is a bacterial/viral contamination or the cells are just sad. Are these just vesicles? These cells look different than HEK293T WT.

Hi every one

I would be very grateful for your expert help

I don't Know if this is applicable? and if so, Is there a company that can installs it ?

Usually SAFT is applied on shear waves using low frequency transducers. Shear waves provide very clean A-scan when compared with longitudinal waves. Due to large number of mode conversions of ultrasonic wave, multiple echoes can be observed in the A-scan acquired using narrow band longitudinal wave transducers. This makes it difficult for the implementation of SAFT technique.

There are two types of ultrasonic transducers: piezoelectric and magnetostrictive.

My question is:

Can the same power supply(generator) used for piezoelectric ultrasonic transducers be used for magnetostrictive ultrasonic transducers without loosing performance?

I want to make a magnetostrictive ultrasonic transducer for homogenizing applications.

I also want to make its power supply by myself.

I need some references (papers, patents, reports, books videos, etc.) that can help me in this way.

I would appreciate your help

I am currently working with recombinant lentiviral constructs to transduce/infect a mammalian cell line with also Polybrene at a final concentration of 8 micrograms per milliliter of transduction/infection media. After trypsinizing my mammalian cell line and centrifuging, I resuspended the cell pellet into media containing 1x pen/strep which I then aliquoted into T75 flasks containing premixed Polybrene and Lentiviral constructs. Will the presence of antibiotics affect the efficiency at which my lentiviral constructs infect my mammalian cells? Thank you very much for your time and help!

I am using 2 ultrasonic assembly for cleaning purpose and I want to increase cavitation intensity.

(1) a ceramic transducer with a diameter of 30 mm and a horn with a end diameter of 8 mm.

(2) a ceramic transducer with a diameter of 40 mm and a horn with a end diameter of 8 mm.

Since the input power of (2) is higher than that of (1), I expected that the sound pressure of (2) is higher than that of (1), but it was not.

I think it is because the acoustic impedance of (2) is much lower than that of (1) (even though the power is high, sound pressure can be lower since Z=p/v is lower).

1. Am I misunderstanding something??

2. If not, how to increase the acoustic impedance of the ultrasonic assembly??

3. How can I estimate the acoustic impedance of the ultrasonic assembly??

4. What is the best?? the acoustic impedance of the ultrasonic assembly should be equal to the acoustic impedance of the media (water in my case) or as high as possible?

I think if the amplitude is large then the acoustic pressure also high.

I have tried to increase the acoustic pressure and use the ultrasonic booster which is known to increase amplitude.

But it did not work. The acoustic pressre measured by hydrophone was almost same as the acoustic pressure of the transducer without booster.

I am wondering

1. What is the relationship between the acoustic pressure and the amplitude.

2. What is the ultrasonic booster. Does it can increase the acoustic pressure??

Hi, does anybody know where to buy holders for air-coupled transducers with which the incident angle of the transducer can be adjusted? I searched online but didn't find anything even non-adjustable holders.

If I want to design an ultrasonic transducer or saw device, then what is the significance of the velocity which propagates through the medium in the form of energy.

Hello Everyone,

I would like to mount ultrasonic transducers on a small cylindrical sample to measure P and S wave velocities (2" diameter and 4" length). Appreciate it If you can provide some references as a starting point on how to design such equipment, sizes, and specifications of ultrasonic transducers, etc.

Thank you

I have an Bolted Langevin Transducer, resonating at its half wavelength frequency at around 52kHz, and the impedance measurement at resonance shows a 200ohm, and a -22° phase angle.

I check online, there are quite a number of different configurations of impedance matching circuit design proposals. I took the LC configuration, where the inductance L is place between the electrical source and the live wire of the piezoceramics, the capacitance is place between the output inductance and ground. So the circuit is simply a low-pass filter configuration.

The impedance measurement for the LC circuit + ultrasonic transducer demonstrates a 48ohm, -4° phase at around 51kHz.

However, when I powered up the device, with and without the LC matching circuit, using the same applied voltage input, the device without matching demonstrates an almost double vibration output compared to the device with matching.

Am I doing something incorrect? I thought bringing the impedance down to 50ohm will match to the electrical source output impedance, and an almost 0° will ensure a maximal power transfer?

Looking forward to your feedback!

Thanks,

Xuan Li

Hello!

I have a question regarding my AAV experiments. I tried to transduce my HEK293T cells with AAV8. I already tested my vector with a gRNA in vitro and had a good knock-down rate, while also confirming the transfection with Lipofectamine 2000 via mCherry signal. Now I wanted to proceed with the production of my AAV8 vector. I checked for the intactness of the ITRs, produced them in HEK293T cells (triple plasmid transfection) and concentrated the AAV8 with PEG8000 and centrifugation steps before that, but did not finish the complete purification due to some technical hindrances (waiting for machines). I checked the viral titer with qPCR by using a standard curve of the same plasmid and a standard curve of a bought AAV8 virus with known titer. I transduced my HEK293T cells in order to check also their actual infecting titer and if they are working (I used a dilution series with a MOI ranging over 10 000). Even with a high MOI and a qPCR checking the viral titer via primers for ITR, I saw no fluorescence signal within the cells (72h incubation).

Suggestions on what could be the possible problem are highly appreciated.

Thank you in advance,

Nicole

We are using a horn-type ultrasonic transducer for cavitation and cleaning purposes.

We experimentally found that the cavitation effect and cleaning effectiveness were decreased when input power was higher than a certain value.

The sound pressure measured by the hydrophone showed a periodic wave pattern when we applied proper input power, but it showed an irregular wave pattern when the input power is high (maximum value of sound pressure was high, but RMS value was low).

I have two questions

1. Does cavitation is promoted when the acoustic field shows a uniform and periodic pattern?? (even the maximum sound pressure is lower). Why??

2. Does the tip of the ultrasonic horn irregularly vibrate when high power was applied?? If not, why does the measured sound pressure showed an irregular pattern??

I am using a Cole-Parmer 750-Watt Ultrasonic Homogenizer. Is it possible to control the frequency of the ultrasonic oscillation on this machine or do I need other pieces of equipment?

I am attempting to make translucent oil in water nano-emulsions following the protocol in this paper. My oil to water ratio will be significantly more however, it needs to be as high as possible while remaining translucent.

The energy setting of my homogenizer its in Joules.

So how do I convert from Hz to J ??

Here are the numbers form the paper but it doesn't make sense to be me because how can a higher frequency have a lower energy if E=hv?

20 kHz 44W cm^-2 = 440000 J

1.6 MHz 16W cm^-2 = 160000 J

2.4 MHz 7W cm^-2 = 70000 J

Here is their method

0.5 mmol of EDOT was added to 25 mL of aqueous solution containing 1.0 M LiClO4 in glass beaker cell. The 20 kHz ultrasonication to the water/oil mixture was conducted with an ultrasonic stepped horn (13 mm diameter, titanium alloy) connected with a 20 kHz oscillator (44 W cm−2, SONIFIER-250D, Branson Ultrasonics Co.) for 5 min. The sequential ultrasonication with 1.6 MHz treatment after 20 kHz was carried out using an ultrasonic transducer (16 W cm−2, Honda Electric Co.) connected with a Pyrex glass cylindrical tube (diameter, 24 mm; length, 75 mm) for 5 min. The further sequential ultrasonication with 2.4 MHz treatment after 20 kHz and 1.6 MHz was conducted by an ultrasonic transducer (7 W cm−2, Honda Electric Co.) connected with a Pyrex glass cylindrical tube (diameter, 24 mm; length, 75 mm) for 5 min.

I want to find the resonance and anti-resonance frequencies of an ultrasonic transducer by analyzing its impedance.

so I need to buy a impedance analyzer or spectrum analyzer or something like that.

but my budget is limited.

do you recommend any device for my application and limited budget? :D

I want to apply a pulse-echo methodology (by using one single transducer as both transmitter and receiver). Do you know how to connect the transducer to the wave generator and oscilloscope to detect both transmitted pulse and echoes?

I have been trying to use the burst feature in manual mode by pressing the trigger button in the wave generator. However, when I do that, the oscilloscope is only capable of reading the wave generated instead of receiving as well the back-wall echo.

I am also using these types of transducers from Stemininc: Piezo Ceramic Plate 20x15x2.1mm 1 MHz, Piezo Ceramic Plate 7x7x0.2mm 250 KHz, and Piezo Ceramic Plate 20x15x3mm 710 KHz. Thus, I'm not sure if they are indicated to use this pulse-echo methodology.

I have two alligator cables connected to the oscillator and to the transducer: 1 to work as the transmitter and one to work as the receiver; and they are both connected in the same wires of the transducer. However, so far, it seems that these alligator cables connected to the same transducer are giving me the same wave. 

Do you know if this equipment as it is is capable of doing these readings:

I am using a manually triggered pulse sine wave of amplitudes of either 10Vpp or 24Vpp, but the outcome is always identical. Should I be using a higher amplitude to make sure I receive the echoes?

Any help would be much appreciated.

I was maintaining modifed (transduced) A549 cell line. They are looking strange Either they are stressed or got some sort of contamination. There are lots of big irregular sized ball like structure, but they are attached. I have tried increasing serum percentage and every possible things that I know but it didn't help me. I have attached a picture, which you may find useful. Thank you.

Good day All,

OEM recommendations for the avoidance of gas/air bubbles are to install the echo sounder and speed log transducers between 1 and 5 degrees in the transverse direction. Has any tank analysis been performed to verify this recommendation.

I have reviewed Dr. Klaus von Bröckel's article "Echo Sounders versus Air Bubbles in Research vessels' on the Hydro International website that that article does not include the figures that are referenced in the article.

If the vessel includes a bulbous bow will installing the transducers between 1 and 5 degrees athwartships closest to the bow help mitigate the effects of bubble sweep down. Installing a keel box is not acceptable for speed KPI considerations.

Thank you very much and kind regards,

I have two IDTs (interdigitated transducers) orthogonal to each other o a piezoelectric substrate. I want to know what happens when an RF signal is applied to both the IDTs at the same time. how to find out the orthogonal interference of two acoustic waves?

I have transduced MCF7 cells with a lentiviral vector containing a tetracycline inducible expression system, but my protein is not expressed in MCF7 even though I selected with puromycin.

I have successfully used the same lentivirus in other cell types, but every time I use it in MCF7 cells it fails.

The puromycin resistance is placed very closely to the protein I wish to express so I don't think the protein insert is lost in the vector?

Are there any suggestions or explanations for this?

Thank you for taking the time to read my question!

I have used both viral supernatant as well as viral particles concentrated by ultracentrifugation to infect EA.hy926 cells. But I have been unable to transduce them. The same viral particles have been able to efficiently transduce other cell lines. I have tried both 8ug/ml and 10ug/ml polybrene, but have not been able to transduce the cells. Can someone please help me out?

is it possible to make a DIY impedance analyzer for checking the resonance frequency of high power ultrasonic transducers? for example a face mask welding ultrasonic transducer

Hi all, I transduced my K562 cell lines with letivirus and use puromycin as a selection marker. When I did the cell viability curve, WT K562 only die at a concentration as high as 90ug/ml, which I don't think is a normal concentration. Unfortunately, when I select my transduced K562 cells using 90ug/ml, all the cells died. When I decrease the concentration to 30ug/ml, the selection didn't work well. Anybody knows what happend to my cell line?

I am doing primary fibroblast cell culture and transduced my cells with a lentivirus with 10^7 TU/mL. I added 7.5 uL of virus to about 250,000 cells to have an MOI of about .3. Of note polybrene was also added at 8uL/mL. When the antibiotic kill curve was done all of the control cells dies but only 1 percent of my transduced cells died. I understand that adding polybrene will increase my transduction efficiency, and given that the 10^7 TU/mL number was generated without polybrene, my actual TU/mL might be higher when used with polybrene. Regardless, I don't think polybrene would change my transduction efficiency from about 25-30% (MOI .3) to 99%. Additionally, my cultures had odd morphologies and a reduction in proliferation that are not expected to arise from my vector (just a promoter-antibiotic resistance-T2A-dCas9).

Does anyone know what the issue might be?

Thanks!

What will happen if the frequency response of the displacement transducer is too small in the explosion tests of civil structures? Does it lead to relative time distortion of the displacement history curve? Or the structural displacement responses would be incorrect?

Hi all, I am using PZT to excite the beam structure and measure the impedance using dynamic signal analyzer. And I also build the finite element model in ANSYS to do harmonic analysis and get the impedance data. My current work is to update the simulation model based on experimental measurements. I read some papers, but all use trial-and-error method. I am wondering if there is an efficient method to conduct model updating.

If make the whole FE model in an optimization loop, the harmonic analysis takes really long time for each iteration. On the other hand, there are too many parameters, and most of them have influence on impedance curve. So the parameters to be updates are also undetermined.

Any suggestions or references are appreciated, thanks.

Hello,

I recently came upon this phrase in the Addgene webpage describing lentiviral transduction.

"Typically cells transduced with lower dilutions of the virus will have higher levels of expression. Consider expanding populations transduced with a variety of dilutions and pick the population that has the most desirable level of expression."

I couldn't understand this, as to my thoughts, higher dilutions of the virus should result in bigger MOIs (more lentiviral particles and more lentiviral genome copies integrated per each cell) and thus should result in higher expression. I am currently troubleshooting lentiviral transduction to BJ fibroblasts, trying out different viral titers.

Could anyone give me an explanation on this?

Thank you.

We are looking for a reliable provider or vendor, that could provide us a technical and financial offer for piezoelectric transducers.

These transducers will be utiliezed for energy harvesting applications and experimentations.

I want to simulate a sono-reactor.

Can anyone share a reliable simulation file for simulation of a power ultrasonic transducer and horn in ANSYS or COMSOL with me please?

I am trying to modify a retroviral vector PMIG II which has 5' LTR and 3' LTR used as promoters. The 5'LTR is followed by multiple cloning site (MCS). I am looking to clone my gene of interest under granzyme B mouse promoter at MCS site. Do I need to remove 5'LTR and 3'LTR in the vector in order to do that? Can 5'LTR drive my granzyme B Promoter?. The vector would be ultimately used to transduce mouse cell line.

Thanks in advance for the feedback.

I've included two pulse-echo plots: One is zoomed out far enough to see the exponential decrease in the "reverberations" following immediately after the pulse is sent out; the other is a close-up of the actual first echo where you can see the first frontside and backside reflections off of the PLA puck.

I've also included a chart showing my immersion transducer setup.

What is causing these undesired reverberations in the beginning? Is my transducer faulty somehow?

I collected ( laser source, US transducers and different optical components

The literature is not very clear on this issue.

In all the papers I've been reading, the dielectric loss is only related to the heat production of the materials under an electric field. This may produce a failure of a device (such as an actuator) by heating it and thus, increasing their electrical conductivity.

My question is related to the effect of the dielectric loss under low voltage in silicone rubber under a system that could dissipate any heat produced. Which will be the real/expected impact on the performance of a transducer device (strain sensor)? How important could this factor be ? (i.e: at 100Hz Ɛ'=40; Ɛ''=10; tanδ = 0.25)

Hi all, I get my admittance data using Impedance Analyzer for the PZT transducer attached to a plate. I measure three times with 15 minutes interval on the first day (fig.1) and then measure three times with 15 minutes interval the next day (fig.2). The obtained curves are different in the same day and also in the different day (fig.3).

I read papers but cannot find how to explain this phenomenon. From the theoretical expression of admittance or impedance, it seems the capacitance of PZT contributes to this difference, if my guess is right, why the capacitance of PZT varies everyday? (The temperature are 25 ℃ with +/- 3℃). Could anyone help to give any hints or references about this? Thanks.