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Temperature
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| PowerLab systems can be used for various biological temperature measurements. |
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Temperature is a physical property of a system that uses the concepts of hot and cold. The object becomes hotter as the temperature increases and vice versa. Macroscopically, temperature determines the direction of heat flow between two objects placed in thermal contact. If the two objects have the same temperature, no heat flow occurs, otherwise heat flows from the hotter object to the colder object. Microscopically, temperature can be defined as the average energy of microscopic motions of a single particle in the system per degree of freedom. In a solid or liquid, these microscopic motions are principally the vibrations of its atoms about their sites in the solid or liquid. In an ideal monatomic gas, the microscopic motions are the translational motions of the constituent gas particles, while a multiatomic gas also include vibrational and rotational motions.
Temperature ScalesTemperature is measured with thermometers that may be calibrated to a variety of temperature scales that include: - The Celsius scale, °C
- The Kelvin scale, K (0 K= -273.15 °C)
- Fahrenheit scale
- Rankine scale (a shifted Fahrenheit scale)
Temperature ProbesThermocouplesThermocouples are commonly used for temperature measurement as they are highly accurate and operate over a broad range of temperatures. They consist of two different metal wires that are welded together at one end (A). These wires generate a thermoelectric voltage between their open ends that changes according to the temperature difference between the two ends, that is, between junction (A) and the reference (R). ThermistorsThermistors consist of an electronic component (semiconductor material) that exhibits a large change in resistance in proportion to a small change in temperature. In comparison to thermocouples, thermistors have a limited (smaller) temperature range; however, they are highly sensitive within this range. The resistance of these devices often changes in a non-linear fashion with temperature and additional instruments required to linearize the reading. Note: Temperature probes may be used to determine cardiac output using the thermodilution method. See the Cardiac Output application page for more information.
LabChartLabChart software (for Windows and Macintosh) combines the familiar simplicity of a traditional strip chart recorder with the powerful analysis features of a digital acquisition system. LabChart software and a PowerLab data acquisition unit provide data integrity, easy selection of hardware settings, powerful online and offline analysis, procedure automation, seamless extraction of experimental data and flexible display options. Acquisition and analysis capabilities can be further increased with LabChart Extensions and LabChart Modules. LabChart Modules are available as part of LabChart Pro and LabChart Extensions are free for download from the website for existing LabChart users.
GLP and 21 CFR Part 11For those researchers working within a laboratory requiring GLP and 21 CFR Part 11 compliance the GLP Client and GLP Server are available for use with LabChart (Windows only) and PowerLab data acquisition systems. For more information, visit the Good Laboratory Practice application page or contact your nearest ADInstruments representative.
Each temperature probe requires its own type of preamplifier which provides a signal to a PowerLab data acquisition system. Thermistors & PreamplifiersThese temperature probes connect to PowerLab data acquisition systems via a They include: They are used to measure skin surface temperatures or nasal air temperatures (a useful indicator of respiratory rate) in the range 5°C to 45°C. Thermocouples & PreamplifiersThe T-type thermocouple probes have a 2-pin T-type plug that is suitable for connection to data acquisition systems via a: The Ultra-fast T-Type Thermocouple (IT-23) is recommended for use with the ML313 Cardiac Output Pod. The thermocouple probes include: - MLT1404 Rectal Probe for Mice (RET-3) – a probe suitable for measuring the body temperature in small animals such as mice, hamsters or rat pups. The probe consists of a thin stainless steel shaft 19 mm long, with a smooth ball tip of 1.7 mm diameter.
- MLT1403 Rectal Probe for Rats (RET-2) – a probe suitable for measuring the body temperature in adult rats. The probe consists of a stainless steel shaft 25.4 mm long, with a smooth ball tip of 3.2 mm diameter.
- MLT1407 Large Animal Rectal Probe (RET-1) – a probe suitable for measuring body temperature in rabbits and larger animals. The probe consists of a flexible, vinyl covered, soft tip with a 1.5m lead and can measure a maximum temperature is 90°C with a time constant of 5.0 seconds.
- MLT1406 Needle Microprobe Thermocouple (MT-29/1) - a fast-response needle thermocouple probe which can be used for measuring temperature in tissues, semi-solids and liquids.
- MLT1400 General Purpose Thermocouple Probe (HT-1) - a probe suitable for measuring temperature in liquids, gases and semi-solids. It has a plastic handle and a 75 mm long stainless steel shaft, and is suitable for temperature measurements to a maximum of 400 °C.
- MLT1401 T-type Implantable Thermocouple Probe (IT-18) - a 0.6 mm diameter implantable probe is suitable for immersion in various solutions, semi-solids and tissue. It can also be used to measure rectal temperatures of small animals and is suitable for measuring temperatures up to 150 °C.
- MLT1402 T-type Ultra Fast Thermocouple Probe (IT-23) - a tissue implantable microprobe with an ultra fast response time of 0.005 seconds. The tip of the thermocouple is just 0.76 mm in diameter, and is inserted into tissue with a supplied 23 gauge hyperdermic needle. It is suitable for temperature measurements to a maximum of 150 °C.
- MLT1405 T-type Implantable Thermocouple Probe (IT-21) - a 0.4 mm diameter implantable probe is suitable for immersion in various solutions, semi-solids and tissue. The isolated probe is totally sheathed in chemical resistant Teflon and is rugged. It can measure temperatures up to 150 °C.
Additional Hardware & Accessories
| Comparison of intracranial pressure measured in the cerebral cortex and the cerebellum of the rat |
| S Rooker, G de Visscher, B van Deuren, M Borgers, P G Jorens, R S Reneman, K van Rossem and J Verlooy, Journal of Neuroscience Methods, 83-88, 2002 |
| ….. the head of the rat (370-490g) was fixed in a stereotaxic apparatus (model DK1962; Ultra Precise Small Animal Stereotaxic, Kopf Instruments, Germany) and a thermistor inserted into the tip of an ear bar was used to measure the tympanic temperature, providing an accurate measurement of brain temperature. A rectal temperature probe was inserted to monitor body temperature, which was controlled with a heating pad connected to a temperature controller unit. The end tidal CO2 (EtCO2) and breathing rate were continuously monitored with an EtCO2-monitor (Capnogard, Novametrix, USA). The left femoral artery was canulated to allow continuous monitoring of the mean arterial blood pressure (MABP) and heart rate (Argon Transducer, Maxxim Medical, Greece).………To measure cerebellar ICP, a burr hole of 2 mm was drilled into the right part of the occipital bone, 2 mm caudal of the cranial edge and 2 mm lateral from the midline, avoiding damage to the sagittal sinus. The first microsensor ICP probe (ICP Neuro microsensor; diameter 1.2 mm, length 4 mm; Codman & Shurtleff Inc., Randolph, MA) was attached to a micromanipulator. The tip was positioned in the sagittal plane with an angle of 358 relative to the horizontal plane and carefully inserted in the cerebellar parenchyma. To measure cerebral ICP, a 2 mm burr hole was drilled into the right interparietal plate of the rat’s skull 4 mm from the midline and 2 mm caudal to the bregma suture. The second microsensor probe attached to a micromanipulator was inserted in the cortical parenchyma with the sensor facing towards the midline. In a frontal plane, the probe was placed at a 708 angle to the horizontal plane to avoid perforation of the lateral ventricle. Insertion depth of both probes was 4 mm.
After surgical preparation and the insertion of the ICP probes, anaesthesia was maintained with 1.5% isoflurane. ICP was then monitored continuously for 25 min.……….. All data were collected with a MacLab computer system (MacLab/8 MK3 Version 3.5, ADInstruments, Australia). |
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| 5'-Adenosine monophosphate and adenosine metabolism, and adenosine responses in mouse, rat and guinea pig heart |
| J P Headrick, J Peart, B Hack, B Garnham and G P Matherne, Comparative Biochemistry and Physiology A, 615-631, 2001 |
| Hearts were isolated from 7-12-week-old male and female wild-type C57-BL6 mice, Wistar rats and Hartley guinea-pigs ……..hearts rapidly excised into ice-cold perfusion fluid. The aorta was rapidly cannulated and the coronary circulation perfused with modified Krebs-Henseleit buffer….all hearts were perfused at an aortic pressure of 90 mmHg. …….Left ventricles were vented with polyethylene apical drains and hearts were instrumented for functional measurements……. The temperature of coronary perfusion fluid was continuously assessed by a needle thermistor located at the entry into the aortic cannula, and the temperature of the water bath assessed using a second thermistor probe. Temperatures were recorded using a three-channel Physitemp TH-8 digital Î thermometer (Physitemp Instruments Inc, Clifton,
. NJ, USA).
For assessment of isovolumic contractile function fluid-filled balloons constructed of polyvinyl-chloride plastic film for mice and thin-walled latex for rats and guinea pigs were inserted into the left ventricle via the mitral valve. Balloons were connected to a P23 XL pressure transducer (Viggo-Spectramed, Oxnard, CA, USA) by a fluid-filled polyethylene tube, permitting continuous measurement of left ventricular pressure. Balloon volume was increased to give end-diastolic
pressures of ~6 mmHg in all species. Coronary flow was continuously monitored via a cannulating Doppler flow-probe (Transonic Systems Inc, Ithaca, NY, USA) located in the aortic perfusion lines and connected to a T206 flowmeter (Transonic Systems Inc, Ithaca, NY, USA). All functional data ventricular and aortic pressures, coronary flow were recorded at a sampling speed of 1 kHz on a 4/s MacLab data acquisition system (AD Instruments, Castle Hill, Australia) connected to an Apple 7300/180 computer. Ventricular pressure signals were digitally processed to yield peak systolic pressure, diastolic pressure, ±dP/dt and heart rate. |
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The material on this page is provided in good faith and believed accurate at the time of writing. No responsibility will be taken, or liability accepted, for damages arising from the use of information herein. Readers are urged to check with respective manufacturers the accuracy of all product related information.
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