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Acquisition Amplification Anti-vibration Cell Injection Iontophoresis Manipulation Manometry Micro-incubation
Noise Elimination Patch-clamp Perfusion Pipette Manufacture Software Stimulation Urodynamics
Inside this Issue
Welcome to the 2013/14 issue of Digitimes, bringing you the latest news from Digitimer and our
partners. Inside this issue, the Product Focus feature takes a closer look at the capabilities of our
renowned NeuroLog System, re-visiting existing modules and informing you about some of the
more recent additions we have made to the range.
We also update you on some new products we now
offer, such as 19” Equipment Racks, Self-Adhesive
Electro-Stimulation and Motor Point Pen Electrodes.
In our Clinical News section, we report on changes
in the way that the QtracW software is supplied, the
success of our DS7A PSARP variant of our popular nerve/muscle stimulator and also update
you on progress with the development of our new D440 Isolated Amplifier.
Self-adhesive Electro-stimulation Electrodes
There is some exciting news from our partners
in relation to new products. AutoMate Scientific have recently launched a couple of new
products to enhance the capabilities of any perfusion system and Scientific Systems Design
have introduced a two new recording chambers, one (MS5) specifically for cells on coverslips
and the other, a tissue chamber (TCKG) suitable for grease-gap recordings from nerve
preparations.
The new TCKG Tissue Chamber from SSD
This issue of Digitimes also reminds you of the variety of other products we manufacture and/
or supply, including a wide range of isolated electrical stimulators, the HEKA patch-clamp,
voltage clamp and voltammetry hardware and software, as well as the ever popular HumBug
50Hz/60Hz Mains Noise Eliminator from Quest Scientific.
You Can Keep in Touch with Digitimer by E-mail or through Facebook and Twitter
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electronically. If you would like to join them, please just let us know and advise us if you still want to receive a paper copy. As well
as the obvious environmental benefits, this method of contact is more reliable as you can register an E-mail address that moves with
you and is not necessarily associated with your place of work or study. Digitimer sends E-mails to registered customers every couple
of months to keep them updated on our products news, also providing application notes and trouble-shooting information. If you
would like to join this mailing list, just drop us an E-mail asking to be added (you can remove yourself at any time).
If you are a fan of Facebook or Twitter, you can also keep up to date with Digitimer news and upcoming events by liking our Facebook
page (www.facebook.com/digitimer) or following @DigitimerLtd on Twitter.
Low Noise, Compact Sources of Constant Current or Constant Voltage Stimulation
The Digitimer DS2A (constant voltage) and DS3 (constant current) Isolated Stimulators are popular in electrophysiology laboratories
all over the world. Their compact and user friendly design has generated a loyal following amongst researchers wishing to precisely
stimulate nerve or muscle from an isolated, low noise power source.
Both units can be triggered manually using the front panel single-shot button or automatically in response to TTL compatible
trigger pulses. In addition, pulse duration can be defined by (i) the settings of the front panel control dials (ii) the duration of
the incoming trigger pulse or (iii) the length of time that the single-shot button is held down. Power for both stimulators is
derived from eleven standard 9V batteries, which offer low noise
and long life. Power is only drawn from the batteries when
a stimulation pulse is given. The DS2A, DS3 or DG2A
Digitimer Ltd
Trigger Generator can be 19” rack mounted
37 Hydeway
using our D121-11 mounting frame which
Welwyn Garden City
will support one or two of these
AL7 3BE, UK
Tel:
+44
(0)1707
328347
instruments.
The popular DS3 (left) and DS2A Isolated Stimulators
Fax: +44 (0)1707 373153
E-mail: sales@digitimer.com
Web: www.digitimer.com/digitimes13
The NeuroLog System - Compact, Versatile and
Future-Proof Solution for Signal Amplification,
Conditioning & Stimulus Generation
The NeuroLog System allows you to perform intracellular, extracellular
isolated EMG/EEG or transducer-based recordings, signal conditioning,
pulse generation or electrical stimulation, within one modular unit.
The NL900D Case & Power Supply Unit (pictured right) allows up to 13 modules
to be installed. This means that a single NeuroLog System can be configured
to amplify several different parameters, such as extracellular spikes, intracellular
NL900D NeuroLog System Rack
potentials or even blood pressure, as well as simultaneously provide outgoing
trigger pulses to other devices or electrically stimulate the preparation of
interest. We also offer the compact NL905 Case (shown below) which holds up to four modules for less demanding applications
and ultimate portability. Because the amplified outputs are analogue voltages, the NeuroLog System is not tied to particular data
acquisition hardware or software, so you can use it with whatever hardware and software you choose. Here, we present some of the
roles NeuroLog System modules can play in various applications.
Isolated Multi-channel Recording
An ideal system for multi-channel AC recording of physiological signals such as EEG, EMG or ECG in the research environment. The
system provides a wide range of amplification and filter settings. The NL824 4-CHANNEL
PRE-AMPLIFIER can be positioned near the recording site, so reducing the length of the
electrode cables and minimising interference. The outputs are connected to the NL820A
ISOLATOR, where further amplification of the signals can be selected on a channel by
channel basis. Further filtering is provided by the various NL134/5/6 or NL144 FILTERS,
while the signal can be conditioned for ADC input using the NL530 CONDITIONER.
NL844 4-Channel Pre-amplifier
Intracellular & Extracellular Recording
Our NL102G DC PRE-AMPLIFIER is perfect for intracellular DC recordings from fluid filled
high impedance electrodes. This double-width module features capacity neutralization,
impedance checking, current injection, low leakage current and minimal DC drift. It is
supplied with a compact headstage and a remote “buzz” box to aid electrode penetration.
For extracellular, differential DC recordings we recommend our NL109 BRIDGE AMPLIFIER
and NL100AK HEADSTAGE. For AC coupled extracellular recordings, the NL100AK
A typical NL905 based
HEADSTAGE and NL104A AC PRE-AMPLIFIER provide an excellent combination. They
Extracellular Recording
can be used in single-sided or differential modes, provide impedance matching for microSystem
electrode recording and feature low noise amplification. Continuously adjustable band-pass
filtering from 0.5Hz to >50kHz is available through the NL125/6 FILTER. In addition, the NL201 SPIKE TRIGGER can be used to
convert spikes into uniform TTL pulses which can then be counted, converted to frequency (using our NL254 RATEMATER) or further
analysed using other modules/software. The NL120S AUDIO AMPLIFIER and NL985S LOUDSPEAKER allow spikes to be audibly
monitored.
Pulse Generation & Stimulation
NL905 based Timing
& Stimulation System
The NeuroLog System range includes a number of timing modules designed to permit flexible
pulse generating protocols. Whether you want to deliver a regular burst of pulses, a preset number
of pulses or continuous stimulation for a set duration, it is likely that the Neurolog System can be
configured to accomplish your needs. Output from our NL301 PULSE GENERATOR and NL304
PERIOD GENERATOR is based on standard TTL, so the system can be interfaced with other devices.
For electrical stimulation requirements, our compact, battery powered NL800A STIMULUS
ISOLATOR produces monophasic or biphasic electrical stimuli and can be driven by the NL510A
PULSE BUFFER (square pulses) or NL512 BIPHASIC BUFFER (arbitrary waveform shapes).
Force, Accelerometry & Pressure Measurement
Our NL109 BRIDGE AMPLIFIER can be used with a selection of force transducers that we offer, allowing
you to measure forces up to 250kgf or coupled to our NEW NL26x ACCELEROMETERS & INTERFACE. The
NL108A PRESSURE AMPLIFIER provides an easy method of monitoring physiological pressure changes
and can be used in combination with your own or our disposable (NL108T2)/ reusable (NL108T4) pressure
transducers. A pressure transducer and appropriate lead can be connected to the pressure amplifier,
allowing continuous monitoring of parameters such as blood or intra-tracheal pressures. The output of
the NL108A can be fed directly to a chart recorder or ADC interface for PC-based acquisition.
A NeuroLog System
Force Transducer
Digitimer Clinical News
In Development - Preview of the NEW Digitimer D440 Isolated EMG Amplifier
In the last issue of Digitimes, we advised readers that a new isolated amplifier was being developed by
Digitimer for clinical EMG recordings like those carried out during nerve excitability testing. The amplifier
will be available in 2-channel and 4-channel versions and will feature a software graphical user interface to
control settings, similar to that for our D360 amplifier. As with the D360, the new amplifier will also allow
control by third-party data acquisition software, via a USB connection to the host PC. We had hoped to
launch the D440 late in 2012, but the project has taken longer than expect and we currently aim to have the
amplifier available for delivery towards the end of 2013.
Prototype D440-4 Amplifier
USB Dongles Now Shipped with QtracW Nerve Excitability Testing Software
Registered users of QtracW Nerve Excitability/Threshold Tracking software will know that licensing was
previously controlled through the distribution of passwords specific to the host computer that QtracW was
installed on. This system worked well until the computer was replaced or experienced a catastrophic failure,
as this required Digitimer to re-issue passwords, causing users some interruption to their research. Recently,
the password system was phased-out in favour of a “USB hardware dongle” which is plugged into a free USB
port on the computer running QtracS or QtracP. Upon despatch, each USB dongle is programmed with a
license expiry date, which can be remotely extended by the end-user upon
payment of the appropriate license fee. This new system not only allows
registered users to more easily move QtracW between computers but also
removes the need for replacement passwords to be issued by us.
Existing users can extract any remaining license time from a passwordenabled QtracW installation and add this time to up to three USB dongles QtracW in use at a Nerve
Excitability Workshop
(one QtracSP and two QtracP) through use of our freely available Dongle
DS5 Constant Current Stimulator
Extend software.
For anyone interested in using QtracW, a 5 year long new-user license can be purchased from Digitimer, which includes one QtracS
dongle for acquisition and two QtracP dongles for analysis/plotting. QtracW is compatible with our DS4 (for animal use) and CE (MDD)
certified DS5 (for human use) Bi-phasic Constant Current Stimulators. You can install and use a 50 day trial of QtracW by downloading
a copy from our website.
Digitimer DS7A PSARP Stimulator Gains Support from Surgeons throughout Europe
In 2008, we were approached by staff at Great Ormond Street Hospital (GOSH, London, UK) who were looking for a suitable stimulator
to use as a muscle locator during surgery, as the device they had previously used was not CE compliant. In a technique pioneered
by Alberto Peña, a surgeon uses a hand held bipolar stimulating probe to map the location of
striated muscle, which is ultimately used to surgically construct an anus in very young children
born with anorectal malformation. Five years after its introduction, the DS7A PSARP has been
supplied to many hospitals in the UK/Ireland, mainland Europe and even South Africa. As interest
in this stimulator has developed, we have registered it with Health Canada (Medical Devices
Bureau Licence No 61911). The DS7A PSARP can be supplied with a foot switch (optional, but
recommended) and a reusable bipolar probe (EtO sterilisation required) or sterile disposable
bipolar probes (packs of 10), which interface with our D185-HB4-2m Output Extension Cable.
DS7A PSARP Muscle Locating Stimulator
Digitimer Now Supplies Axelgaard Self Adhesive & Motor Point Pen Electrodes
Our selection of Neurodiagnostic Accessories has been expanded by the recent addition of the self-adhesive electro-stimulation
electrodes manufactured by Axelgaard in the USA. Axelgaard offer several types of electrode, including the popular ValuTrode and
PALS Platinum ranges which are available in many different sizes. The electrodes are specifically designed for electrical stimulation
applications and may be re-used a number of times. Each Axelgaard electrode features a short lead wire terminating in a
2mm socket which allows them to be interfaced with our clinical stimulators
using our D185-HB4 cables and short adaptor leads (D-SP338 (available in
pairs of 30cm or 90cm lengths).
Some DS7A/AH users have asked us to supply motor-point pen
electrodes along with our stimulators, so we have now added one
to our catalogue. This small monopolar pen-style electrode
(part code G.MPPE) features a 4mm stainless steel probe
Our New
Motor-point
and is connected to the stimulator using the same 2mm
Pen Electrode
connection as the Axelgaard electrodes introduced
Self-Adhesive Electro-Stimulation Electrodes
above.
News from Our Partners
NEW Two Recording Chambers and a Slice Holder (Harp) from Scientific Systems Design
Scientific Systems Design are familiar to many electrophysiologists as a manufacturer of high-quality brain slice chambers and as part
of their continued product development, they have recently introduced two new chambers and a slice holding “harp” accessory.
The MS5 Microscope Stage Chamber has been designed for use on microscope stages to view glass cover slips containing cultured
cells. Cover slips smaller than 25mm with cell cultures are placed directly on top of a
MS5 Microscope
fixed glass cover slip at the base of the MS5. The chamber can be used with inverted
Stage Chamber
microscope stages but the glass cover slip at the base of MS5 will add 200µm to the
existing cultured cover slip thickness. The glass-to-glass adhesion between the cover
slips keeps the sample stable for viewing under submerged conditions. The particular
feature of this chamber is the raised glass cover slip that allows the cover slip containing
cultured preparations to be slipped off side-ways and returned to the incubator if
required. Heating is possible through use of the PTC03 temperature controller unit and
MH02 in-line heater. Adaptor plates are available for various microscope stages.
The TCKG Tissue Chamber has been designed to support various types of preparations
in experimental test media and allow recordings to be made from nerves arranged across a grease gap, facilitated by a removable
partition between the nerve and associated preparation. This chamber consists of two main cells, one is a large diamondshape for containing the preparation and the other is a smaller oval-shaped cell where nerve ends are arranged for making
electrical recordings. The base contains temperature control heating and sensor
elements connected to a separately available proportional temperature controller PTC03.
The warmed perfusion solution in the spiral then flows over the preparation in a
diamond-shaped area and exits at the opposite end where it can be sucked off from
a tube fitting. In addition there is provision for the diamond-shaped cell to maintain
high humidity and control the gaseous environment for experimental anoxia or other
gas combinations.
Finally, SSD now offer a U-shaped Brain Slice Holder (U-NET) for use with their range of
recording chambers. This U-shaped anchor is based on the harp-like design and consists of TCKG
a stainless steel U-shape which has six or more nylon threads passing across the aperture. Tissue Chamber
The holder is 13mm by 10.5mm, with an aperture of roughly 5.5mm by 10.5mm.
“T” Revision of the HEKA EPC10 USB Patch-clamp Amplifier Extends Ranges
With the EPC10 USB Revision “T“, HEKA has added a few new hardware
features improving the specifications of the EPC10 USB for the following
applications (i) Current Clamp Measurements (extended voltage
measuring range (+/-5V), extended current injection capability (by a factor of 5) and filtering
of the voltage signal) (ii) Electrochemical Measurements
(extended voltage stimulus range to +/- 2V). The EPC10
EPC10 USB Patch-clamp Amplifier
USB Revision “T“ amplifiers also provide the option to
use “Filter2” for the current or voltage signal. This new feature allows filtering of the voltage
signal in a current clamp measurement using the Filter2. If the Filter2 mode is set to “V_Bessel“
or “V_Butterworth“, then the current signal is filtered by Filter1 only.
EPC800 USB Patch-clamp Amplifier
NEW Floor-Standing and Bench-Top 19” Equipment Racks
Digitimer has recently started supplying 19” racking for electrophysiology rigs. We now offer floor-standing and
bench-top racks in various sizes and two colours, supplied with a range of optional accessories such as shelving,
casters and compatible mounting screws. The racking units are manufactured by an ISO 9001:2008 certified
engineering company based in North America and can be shipped “flat-packed” directly to our customers from
their factory to reduce delivery costs.
The floor-standing racks are available in light grey or black, seven different heights (20U
to 44U) and three different depths (16”, 23” & 30”). Doors are optionally available along
with a variety of other accessories.
For bench-top applications, there are two heights available (12U and 16U), in black only.
Being only 12” deep, these units are particularly useful where space is more limited and
the rig can be assembled on or next to a fitted laboratory bench. As with the floorstanding racks there is an extensive range of accessories, including vented and unvented
shelves, mounting screws and cable management systems.
Floor-standing 19” rack unit
Bench-top 19” rack unit
News from Our Partners
NEW Oxygen8 and BubbleStop from AutoMate Scientific
Enhanced Capability for any Perfusion System
Do you need rapid liquid switching with oxygenated solutions? How do you bubble
Carbogen gas into closed, pressurised reservoirs? That’s the engineering problem
AutoMate Scientific has solved with several years of research: bubbled, pressurised
perfusion. You can add the new Oxygen8 to any new or existing gravity perfusion
system from AutoMate Scientific, any thirdparty manufacturer, or even homemade rigs. Connect to your desired
gas (30 to 100 psi). Available in fouror eight-channel configurations.
Syringe reservoirs may be placed in
a water bath for temperature control
or combine with the AutoMate
BubbleStop™ syringe heater (left and
below).
AutoMate Oxygen8 System
Of course, bubbles can also be an
unwanted side effect of solution temperature changes. As solutions warm, dissolved
gases come out of solution and form bubbles in perfusion tubing. It is a particular
problem with in-line heaters where the temperature rises dramatically. The best cure for
bubbles is to pre-warm your solutions, so AutoMate Scientific has recently introduced
the BubbleStop™ Syringe Heater with integrated temperature sensor and feedback
AutoMate BubbleStop Syringe Heater
control. Just set the temperature on the BubbleStop a few degrees higher than room
temperature or your in-line heater, and the warmed solutions will release gas within the syringe reservoirs to the maximum gas
concentration for that temperature. Even if they cool and re-heat again inside the perfusion tubing, they will not release any more
gas bubbles.
NEW Narishige DMA-1511 Motorized Stereotaxic Micromanipulator
Mounting the DMA-1510
on the SM-11
micro-manipulator
The Narishige range of stereotaxic instrumentation
has been expanded with a few updated models of
stereotaxic frames and the addition of a new motorized
micromanipulator available in two versions, with (DMA1511) and without (DMA-1510) a digital movement scale.
The DMA-1511 is controlled remotely by pressing keys
on a keypad and a particular position can be easily
set and logged as a reference point with the
distance from this reference point continuously
displayed. The DMA-1511 is able to calculate
coordinates automatically using positional
measurement, therefore eliminating the
Components of the DMA-1511 System
need to work out the distance travelled
during or after an experiment. Use of motorized control allows the manipulator to have
an array of extra features and support future upgrades, making it versatile and suitable for
a variety of applications. For instance, the DMA-1511 can be operated in four movement
modes - Free Drive, Step Drive, Distance Set Drive and Coordinate Set Drive. The DMA-1510
and 1511 are designed to replace the z-axis of the SM-11 manipulator, which can be mounted
on the Narishige SR/SN series of AP frame bars.
ThorLabs Science Desks and Faraday Cages
ScienceDesks are high-quality ergonomic workstations with a modular system of accessories,
making them ideal for use in electrophysiology and imaging applications. The active-air and passive
anti-vibration frame options provide the user with a tabletop that is isolated from vibration. The
tabletop is also protected from incidental contact because it rests inside the frame’s outer rails. We
offer stainless steel tabletops with or without tapped mounting holes. The upper and lower rails
on the ScienceDesk frame allow the user to strategically place shelves and other accessories so that
supporting equipment can be in close proximity to the isolated surface without being on it. The
900mm by 750mm tables are also compatible with a table-top Faraday cage.
Other Digitimer Products
DS4 Computer-controlled Isolated, Bi-phasic Current Stimulator
The DS4 has been developed to meet the needs of scientists who require a stimulus isolator that can output a bi-phasic isolated
constant current stimulus in response to an external voltage waveform, provided by a computer DAC via software. The DS4 accepts a
variety of voltage input ranges (±1V, ±2.5V, ±5V and ±10V) and produces a constant current stimulus output in 4 overlapping ranges
(±10µA, ±100µA, ±1mA and ±10mA) from a compliance voltage of ±48V. In addition, the DS4
has a GATE input which allows multiple DS4’s to be connected to a single analogue voltage
source, with each DS4 being digitally enabled, separately.
One of the problems with stimulators that make use of an external voltage source to define
a stimulus waveform is that small offsets or noisy baseline signals from the DAC’s used to
drive them can result in unwanted battery drain or perhaps worse, low amplitude stimulation.
The DS4 uses a special “inactivity sensor” to monitor the input voltage and disable the DS4
output if this voltage falls below 0.15% of the full scale value (in +ve or -ve directions) for a user
selectable time period of 100ms, 200ms, 1s or 2s. Unlike other devices which only produce
DS4 Bi-phasic Stimulus Isolator
an output when the input voltage exceeds a threshold value, this “inactivity sensor” reduces
battery usage and damaging “leak currents” during infrequent stimulation, while at the same time maintaining low levels of zero
crossing distortion for repetitive waveforms. The DS4 uses an external power supply for the control circuitry and readily available/
inexpensive batteries to provide the opto-isolated stimulus voltage source.
DG2A Trigger Generator - Repetitive TTL Output for Triggering our Stimulators
The DG2A Trigger Generator is a compact, free-standing, battery powered device which can be used to generate trigger pulses
necessary for repetitive stimulation. Also featuring DELAY controls, it can be used for determining nerve
or axonal Effective Refractory Period (ERP) through the production of a delayed second pulse.
Various modes allow output pulses to be produced singularly, continuously or in a burst, with the burst/
train duration and pulse frequency determined by the front panel controls. In each of the modes (except
FREE-RUN), outputs can be initiated either by the front panel push button, a TTL compatible trigger/
gating pulse or a suitable foot switch. The unit is especially suitable for use with our range of isolated
stimulators.
DG2A Train/Delay Generator
D330 MultiStim - Multi-channel Stimulation for Isolated Tissues and Cells
The D330 MultiStim System is a modular and versatile multi-channel stimulator for
biomedical scientists requiring accurate in vitro field stimulation of multiple low impedance
tissue preparations or isolated cells with different stimulating voltages or currents. Timing
modules are available to generate pulses, variable in frequency and duration, which can
be controlled as trains using a gating waveform, variable in repetition rate and duration or
pulse count. Sockets are fitted to allow full external control and synchronisation with other
equipment, if required.
The D330 MultiStim System comes as a 19” rack-mountable unit that can house up to ten
D330 MultiStim System
stimulation channels - along with the pulse train generator, gating and meter modules. In
order to help with module selection, a number of application diagrams are downloadable from the Support section of our website
(www.digitimer.com/support).
Mains Noise Problems? You Can Remove 50/60Hz Mains Noise Without Filtering!
Humbug Noise Eliminator
Digitimer Ltd.
A remarkable device from Quest Scientific, the HumBug removes unwanted mains noise from
an analogue signal without any of the “side effects” of filtering. The HumBug continuously
monitors the mains noise and subtracts it from the signal in real time, without any waveform
distortion, frequency loss, DC shift, signal attenuation or phase errors.
If you have a problem with excessive mains interference and you haven’t been able to
remove it effectively by conventional means, then perhaps the HumBug is for you.
Please contact Digitimer to arrange a no obligation loan (UK customers only).
37 Hydeway, Welwyn Garden City, AL7 3BE, UK
Tel: +44 (0)1707 328347 Fax: +44 (0)1707 373153
E-mail: sales@digitimer.com
Web: www.digitimer.com/digitimes13