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Engineering Creativity for Neuroscience

 

 

Museum of Equipments

 

 

The currently manufactured constructions of Supertech Instruments can be seen on the Products page. But there were much more equipments developed and manufactured during the long history (since the establishment in 1991) of Supertech Instruments. Most of them are out of date and they have been simply removed from this website as their newer versions have been introduced. But there were a few really interesting, delicate or special equipments developed by Supertech Instruments, which are already not manufactured. The list below is a short memorial of the discontinued, but most valuable development projects and products of our Factory.

 

There is another purpose, why we publish the most interesting former constructions of Supertech Instruments. Our efforts are mainly focused on design and development activity. We manufacture many products, but we are always working on new development tasks. This collection below shows those topics, in which we have notable former experience and knowledge. Upon request any of them or parts of them can be restarted, renewed, modified or further developed in the future. Design of Special Equipments page gives you some more information about the possibility of common development or design of measuring equipments for your unique purposes.

 

 

 

Increasing-Temperature Hot-Plate

 

It was developed in 1997. In that time only one similar equipment was available worldwide.

 

Our Increasing-Temperature Hot-Plate test equipment was designed for determining the pain threshold in rats or mice. The temperature is slowly increasing with variable heating rates from non-noxious levels until a response is observed or a cut-off temperature is reached. The response is the licking of the hind paw, and the corresponding plate temperature represents the recorded nociceptive end-point. The advantage of Increasing-Temperature Hot-Plate test over the standard constant-temperature hot-plate test is the higher sensitivity (better in studying the analgesic effects of mild analgesics), and the lack of influences of pre-exposure to the hot-plate before testing.

 

The equipment was controlled by an IBM-compatible industrial standard PC through its standard Centronics (parallel) port. All the parameters were controlled by the program running on the computer. Moreover the cut-off temperature for safety's sake was controlled by the built-in microcontroller located in the Increasing-Temperature Hot-Plate equipment, too. A plexiglas box was placed on the top of the plate for possible clear observation of the animal.

 

            Click on the picture to get it in full size

 

    At an exhibition, with many other equipments

 

Technical data:

 

Heating elements: a delicate heater surface structure was developed especially to use in this equipment

 

Maximal temperature difference between the centre and the edge of the plate: 0.5 Centigrade

 

Heating rates: can be set from 1 Centigrade/min to 6 Centigrade/min, controlled by the PC software. The equipment can be used with higher heating rates (up to 12 Centigrade/min), but the temperature difference on the plate will be increased over the specified value in such cases

 

Cooling: contact heat dissipation

 

The size of the heated working surface on the top of the equipment: 200 mm x 150 mm

 

The height and the volume of the plexiglas box: 250 mm, 3 liters

 

Computer program: required an IBM-compatible PC running under MS Windows 98 (or higher) operating system

 

Starting temperature of the measurements: room temperature

 

Cut-off temperature (hardware, and firmware controlled): can be set from 30 Centigrade to 54 Centigrade

 

Cut-off temperature (controlled by the PC software): can be set from 30 Centigrade to 54 Centigrade

 

Dimensions without the plexiglas box: 330 x 260 x 130 mm

 

References:

 

Hunskaar, S., Berge, O.G., Hole, K.: A modified hot-plate test sensitive to mild analgesics. Behav. Brain Res. 2: 101-108, 1986.

 

Tjolsen, A., Rosland, J.H., Berge, O.G., Hole, K.: The increasing-temperature hot-plate test: an improved test of nociception in mice and rats. J. Pharmacol. Methods 3: 241-250, 1991.

 

Almasi, R., Petho, G., Bolcskei, K., Szolcsanyi, J.: Effect of resiniferatoxin on the noxious heat threshold temperature in the rat: a novel heat allodynia model sensitive to analgesics. British Journal of Pharmacology, 139(1): 49-58, 2003.

 

 

Juxtacell BioAmp

 

This equipment was a further development of our universal biological BioAmp amplifier. This equipment was optimized for juxtacellular recording (extracellular single cell recording with simultaneous electrophoretic application of tracer solution onto the examined cell).

 

    Click on the picture to get it in full size

 

 

Analog Commander

 

Analog Commander was a special, single-processor version of the BioStim Pulse Pattern Generator. It was designed to work as an analog command generator for Axopatch patch-clamp amplifiers manufactured by Axon Instruments. Analog Commander had got microprocessor-based bipolar pulse pattern generator and calibrated analog voltage output controls (helical potentiometers).

 

    Click on the picture to get it in full size

 

 

Laser Heat Exchangers

 

This was a special product line of Supertech Instruments. The Laser Heat Exchangers were microprocessor-controlled cooling regulators for huge-power industrial lasers. They provided a volume-controlled, cold water flow to cool the lasers.

 

We have developed different Laser Heat Exchangers up to 50 kW. In the pictures you can see an example.

 

           Click on the picture to get it in full size

 

 

Lick Detector (Spout) for Monkey

 

This dual-channel spout equipment was used to provide two different (e.g. sweet and disgusting) solution flows for a monkey to drink. The two spouts and their connection tubes were independent from each other. The geometry of the mouthpiece was optimized for monkeys. There was an optical detector in front of the spouts. The optical axle of the infrared beam was located below the spouts with 5 mm. The electronic box (not shown in the pictures) generates a standard TTL level of output pulse for every touches of the tongue.

 

        Click on the picture to get it in full size

 

 

Low-cost, General Purpose, 16-channel Data Acquisition Program

 

Supertech Scope was a simplified, low-cost, general purpose, 16-channel data acquisition program. The full bandwidth of the program was 100 kS/s, but it was limited by the A/D converter card itself, not by the software. The effective bandwidth for one channel could be calculated by division of the full bandwidth with the number of the A/D converter channels used actually. The Supertech Scope program could be used on PCI-1711 (PCI bus version), or PCL-812 (ISA bus version) data acquisition cards manufactured by Advantech.

 

 

Combined Heater for Brain Slice Chamber

 

This heating equipment controlled the temperature of the brain slice chamber and the incoming solution flow together. Later there were new equipments introduced into our product choice instead of this Combined Heater. These newer and current alternates are the In-line Solution Heaters.

 

            Click on the picture to get it in full size

 

As you can see in the pictures, the plastic tube could be changed by the user in case of any dirt of infection.

 

With a stainless steel chamber the heat contact to the brain slice was perfect. We found that plexiglas, teflon or other plastic chambers could not be heated and controlled perfectly.

 

In this Combined Heater there was an internal temperature sensor, as well.

 

 

Medical Soft Laser

 

This equipment has been developed for human applications in dentistry, dermatology, pediatrics, urology and gynecology. Its internal construction and its power supply complied with the EN 60601-1-2:2002 human medical patient safety standard.

 

Medical Soft Laser SL-4a was a universal soft laser equipment. It could drive any kind of laser diode with any wavelength, up to 1W of optical power (1W is the upper power limit of the soft lasers). This feature provided the opportunity to connect any kind of special headpiece to the equipment. The built-in software provided various lighting patterns for the different application fields.

 

By default we enclosed a headpiece of 13 mW power and 635 nm wavelength.

 

    Click on the picture to get it in full size

 

 

Warm Air Jet Heater System for Incubator, Objective or Sample

 

The base of this unique heating method was producing high volume of heated air inside the incubator or around the objective or the sample. The flow rate of the air mass and the temperature of the outgoing air flow was accurately controlled. The controller equipments were universal and there were task-specific mechanical and/or thermal interfaces and nosepieces for every heated object.

 

            Click on the picture to get it in full size

 

In the pictures you can see the precise heating of an objective without touching the objective mechanically. This was the main goal of the Warm Air Jet Heater method, to protect the expensive and sensitive objective. These pictures show a prototype of the nosepiece.

 

Warm Air Jet Heater System for Objective system was a set of the following equipments:

    - Jet Air Flow Heater Controller with built-in temperature meter

    - Physiological - Biological Temperature Controller TMP-5b

    - Nosepiece for the objective, with built-in digital DS1820 temperature sensor

 

 

MultiAmp V.5 Multichannel Biological Amplifier System

 

In the past there were three different amplifier systems (BioAmp, MultiAmp and LinearAmp) in our product choice, because the three product lines were optimized for different application fields. BioAmp is an up-to-date, highlighted product group of Supertech Instruments for many years, even until now. MultiAmp and LinearAmp families have been retired. This paragraph describes the MultiAmp amplifier family.

 

MultiAmp was a modular, expandable, multichannel biological amplifier system. We manufactured it for 15 years. It was a great success. It survived five versions under continuous development.

 

MultiAmp amplifier family was especially powerful in multichannel applications, since such a level of reliability and flexibility was unthinkable in other analogue amplifiers. The top of all that, our MultiAmp amplifier system offered a very reasonable price level in comparison to the number of the amplifier channels. The most important aim during its development was to remove all that features (and the appropriate circuits) which were substituted in the biological data acquisition software packages. This way the dimensions of the circuits could be decreased and the number of channels could be increased efficiently.

 

    An example: the smallest (8-channel) MultiAmp system

 

MultiAmp's Main Fields of Applications

 

    - EEG Brain Mapping

    - Multichannel recording from brain slices

    - Chronic multichannel recording 

 

The Modular Structure of the MultiAmp System

 

The number of the amplifier channels could be configured in multiples of 8. There were two different amplifier units in our choice. One of the amplifier units was an 8-channel equipment and the other amplifier unit was a 16-channel equipment, where the 16 channels were divided into two 8-channel parts and they could be programmed independently. The Power Supply unit was a separate equipment. From one Power Supply unit a maximum number of 64 amplifier channels could be powered. Certainly, more than 64 amplifier channels could also be installed in one recording system, but for higher (more than 64) channel numbers, more than one Power Supply unit should have been installed. The following list shows the necessary elements to build a given number of the amplifier channels:

    8-channel system: one Power Supply unit and one 8-channel MultiAmp amplifier unit

    16-channel system: one Power Supply unit and one 16-channel MultiAmp amplifier unit

    24-channel system: one Power Supply unit, one 16-channel and one 8-channel MultiAmp amplifier units

    32-channel system: one Power Supply unit and two 16-channel MultiAmp amplifier units

    48-channel system: one Power Supply unit and three 16-channel MultiAmp amplifier units

    64-channel system: one Power Supply unit and four 16-channel MultiAmp amplifier units

 

In the pictures you can see the building bricks of the MultiAmp system: Power Supply, 8-channel amplifier unit and 16-channel amplifier unit.

 

            Click on the picture to get it in full size

 

MultiAmp was a programmable amplifier, but it had no sampling circuits in the signal path at all. In other words, it was controlled by a built-in microcontroller or a remote computer, but it had got only high-performance, low noise, low distortion analogue amplifier circuits. This feature was indispensable when the researcher used averaging technique to process the output signals of the amplifier. The internal microcontroller and the optional digital port (which offered remote control capability from a PC) were optically isolated from the amplifier stages. This way we could connect all the advantages of the high accuracy analogue amplifier circuits and easy usage of digital control.

 

Technical Data

 

In the MultiAmp system the High Pass Filter had got 4 possible positions, and the Gain had got 8 possible positions. The Low Pass Filter was fixed to 8 kHz in the analog circuitry by default. Certainly MultiAmp was available with other Low Pass filter setting upon request, as well. The actual High Pass Filter and Gain values, realized during the manufacturing process were orderable with the default parameters, but they could be requested with special values, to meet any special requirements, as well. The default values of the Filter and Gain sections were the following.

 

High Pass Filter Low Pass Filter Gain
0.0126 Hz (12.64 s) fixed to 8 kHz 200
0.16 Hz (1 s)   500
1 Hz   1,000
100 Hz   2,000
    5,000
    10,000
20,000
    50,000

 

Headstages of MultiAmp

 

    Click on the picture to get it in full size

 

We offered 8-channel monopolar (single-ended) and 8-channel differential headstages for MultiAmp in our standard product choice. There were some applications, where the most important aspect was the size of the headstage (e.g. freely moving mice and neonatal rats). For such applications we have developed 8-channel and 16-channel interfaces to connect specialized 3-rd party headstages to the MultiAmp system.

 

 

LinearAmp V.4 Signal Conditioner Amplifier

 

In the past there were three different amplifier systems (BioAmp, MultiAmp and LinearAmp) in our product choice, because the three product lines were optimized for different application fields. BioAmp is an up-to-date, highlighted product group of Supertech Instruments for many years, even until now. MultiAmp and LinearAmp families have been retired. This paragraph describes the LinearAmp amplifier family.

 

LinearAmp amplifier was optimized for high-precision signal conditioning and recording tasks in electrophysiology. It survived four versions under continuous development.

 

    Click on the picture to get it in full size

 

Technical Data

 

The most sophisticated feature of LinearAmp was its Low Pass Filter. The Low Pass filter circuit was an 8-pole, Bessel-type filter with linear phase response. This special, high quality Low Pass Filter was necessary to realize the anti-aliasing function, which is indispensable before the analogue to digital conversion.

 

In LinearAmp the High Pass Filter, the Low Pass Filter and the Gain had got 8 possible positions. The default values for the Filter and Gain sections are listed below.

 

High Pass Filter Low Pass Filter Gain
DC (0 Hz) 100 Hz 0.5
0.16 Hz (1 s) 200 Hz 1
0.53 Hz (0.3 s) 500 Hz 2
1.6 Hz (0.1 s) 1 kHz 5
5.3 Hz (0.03 s) 2 kHz 10
10 Hz 5 kHz 20
30 Hz 10 kHz 50
100 Hz 20 kHz 100

 

In every amplifier channel there was a dedicated DC offset correction circuit, even in a multi-channel system. The voltage range of the offset correction was +/- 200 mV, with 0.1 mV of resolution. There were two different options for the offset correction circuit. One of them was the analogue version with a 10-turn helical potentiometer and a digital voltmeter on the front of the equipment. That is what you can see in the picture above. The other version was the digital realization of the same task as a separated microcontroller, dealing with the numerical control of the offset voltage. This digital offset correction method is currently used in BioAmp DC amplifier system. You can read its detailed description in the

 

The Notch Filter (hum noise filter) of the LinearAmp was tuned to 50 Hz (or optionally to 60 Hz). The Notch Filter could be switched on and off in the software running on the front plate microcontrollers. The rejection ratio of the Notch Filter on its central frequency was 40 dB.

 

 

Table-top Incubator

 

This equipment was developed to compete with the little table-top incubators. The internal temperature of the incubator was regulated by a Physiological - Biological Temperature Controller with the accuracy of 0.5 Centigrade. The internal atmosphere was controlled by a Carbogene Gas Conditioner Unit. We have completed the prototype development process perfectly with promising results. The prototypes became ready, but unfortunately the manufacturing process has never been started.

 

            Click on the picture to get it in full size

 

 

DC Stimulator

 

DC Stimulator was a special stimulator developed for human cranial electrotherapy. It provided a stimulation using weak direct current (transcranial Direct Current Stimulation tDCS). The electrical charge and current densities applied by the equipment were far below the threshold for releasing a stimulus and had a modular effect on existing neuronal elements. Depending on the duration, output current, current density and frequency, the stimulation was effective on inhibiting or activating the cortical activity.

 

Technical Data

 

Output current ranges:

    0 - 100 nA

    0 - 1 uA

    0 - 10 uA

    0 - 100 uA

 

Compliance voltage: 500 V

 

Fully isolated, floating power supply for the output circuitry

 

There was a microcontroller-based timer and sequence controller with 2x16 character LCD on the front plate. This controller provided precise timing of the output current.

 

The programmable active output period was in the range of 10 - 600 sec, with 10 sec of resolution

 

There was a nonvolatile memory in the controller to store the setup parameters

 

Digital real-time current and voltage monitors were located on the front plate

 

 

 

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