Thermometer Probe Research Articles

Temperature determination of (CF3I) N clusters in a beam by time-of-flight measurements of IR-laser excited SF6 molecules sublimating from the surface of clusters

The method is described and the experimental results are presented on the temperature determination of the (CF3I) N clusters in a beam (N ⩽ 102 is a number of monomers in a cluster) using SF6 molecules from intersecting molecular beam as probe thermometers. The SF6 molecules are captured by clusters in the crossed cluster and molecular beams and, after a certain time, sublimate from the surface of clusters carrying information on the velocity and temperature (internal energy) of clusters. Using time-of-flight (TOF) method the kinetic energy (velocity) of sublimated SF6 molecules was measured and the temperature of clusters was determined to be T cl = (88 ± 15) K.

Measurement of nanoparticle temperature in a (CO2) N cluster beam using SF6 molecules as tiny probe thermometers

A temperature measurement technique using SF6 molecules as tiny probe thermometers is described, and results are presented, for large (CO2)N van der Waals clusters (with N ≥ 102) in a cluster beam. The SF6 molecules captured by (CO2)N clusters in crossed cluster and molecular beams sublimate (evaporate) after a certain time, carrying information about the cluster velocity and internal temperature. Experiments are performed using detection of these molecules with an uncooled pyroelectric detector and infrared multiphoton excitation. The multiphoton absorption spectra of molecules sublimating from clusters are compared with the IR multiphoton absorption spectra of SF6 in the incoming beam. As a result, the nanoparticle temperature in the (CO2)N cluster beam is estimated as Tcl < 150 K. Time-of-flight measurements using a pyroelectric detector and a pulsed CO2 laser are performed to determine the velocity (kinetic energy) of SF6 molecules sublimating from clusters, and the cluster temperature is found to be Tcl = 105 ± 15 K. The effects of various factors on the results of nanoparticle temperature measurements are analyzed. The potential use of the proposed technique for vibrational cooling of molecules to low temperatures is discussed.

Universal probe method for measuring the temperature of large clusters (nanoparticles) in a cluster beam

A universal probe method for measuring the temperature of large clusters (nanoparticles) in a cluster beam has been proposed and experimentally implemented. The temperature of large van der Waals clusters (nanoparticles) (CO2)N (where N ⩾ 102 is the number of monomers in a cluster) in the cluster beam is measured using this method with SF6 molecules as miniature probe thermometers. The SF6 molecules are captured by the (CO2)N clusters in intersecting cluster and molecular beams and sublimate from the surface of the clusters, carrying information on the velocity and temperature (internal energy) of the clusters. The velocity (kinetic energy) of SF6 molecules sublimating from the surface of the clusters has been measured by the time-of-flight method and the temperature of the clusters has been determined as Tcl = (105 ± 15) K.

Temperature determination of (CO 2) N nanoparticles in a cluster beam using SF 6 molecules as probe thermometers

The method is suggested and the experimental results are presented on the temperature determination of (CO 2) N clusters (nanoparticles) ( N ⩾ 10 2 is a number of monomers in a cluster) in a beam using SF 6 molecules from intersecting molecular beam as probe thermometers. The molecules are captured by clusters and, after a certain time, sublimate from the surface of clusters carrying information on the velocity and temperature (internal energy) of clusters. Using time-of-flight (TOF) method the kinetic energy (velocity) of sublimated SF 6 molecules was measured and the temperature of clusters was determined to be T cl = (105 ± 15) K.

Regulation of the Proteasome by Neuronal Activity and Calcium/Calmodulin-dependent Protein Kinase II

Protein degradation via the ubiquitin proteasome system has been shown to regulate changes in synaptic strength that underlie multiple forms of synaptic plasticity. It is plausible, therefore, that the ubiquitin proteasome system is itself regulated by synaptic activity. By utilizing live-cell imaging strategies we report the rapid and dynamic regulation of the proteasome in hippocampal neurons by synaptic activity. We find that the blockade of action potentials (APs) with tetrodotoxin inhibited the activity of the proteasome, whereas the up-regulation of APs with bicuculline dramatically increased the activity of the proteasome. In addition, the regulation of the proteasome is dependent upon external calcium entry in part through N-methyl-D-aspartate receptors and L-type voltage-gated calcium channels and requires the activity of calcium/calmodulin-dependent protein kinase II (CaMKII). Using in vitro and in vivo assays we find that CaMKII stimulates proteasome activity and directly phosphorylates Rpt6, a subunit of the 19 S (PA700) subcomplex of the 26 S proteasome. Our data provide a novel mechanism whereby CaMKII may regulate the proteasome in neurons to facilitate remodeling of synaptic connections through protein degradation.

Disruption of the meprin α and β genes in mice alters homeostasis of monocytes and natural killer cells

Meprin metalloproteases are implicated in inflammatory bowel disease, which involves dysfunction of immune cells. However, the roles of meprins in the immune and hematological system remain uncharacterized. In this report, we demonstrate that meprins were expressed in the hematological system, and meprin alpha/beta null (alpha(-/-)/beta(-/-)) mice had decreased prevalence of resident monocytes and natural killer (NK) cells in blood, with a concomitant accumulation of inflammatory monocytes and NK cells in bone marrow. In contrast, T and B lymphocytes were not affected by meprin deficiency. In response to acute inflammation induced by intraperitoneal injection of thioglycollate, meprin-deficient mice exhibited higher body temperature than wild-type mice, which was correlated with retention of inflammatory monocytes, but persistent low prevalence of NK cells in blood. These results indicate that meprin metalloproteases play important roles in the homeostasis of monocytes and NK cells, and possibly are involved in egress of these two type cells from bone marrow and homing to the periphery. Our findings are the first report to demonstrate that metalloproteases affect homeostasis of leukocytes, which have important implications for understanding physiology of and pathogenesis in the hematological system.

Method for Compensating Heat Flux Errors in Mini-TPW Cell Measurements

Small triple-point-of-water cells (mini-TPW) are used in laboratories to monitor the stability of PRTs. Compared with a standard TPW cell, heat flow in the thermometer well usually disturbs the apparent equilibrium temperature to a larger extent in a mini-TPW cell due to its smaller dimensions. In this paper, the heat flow effect is studied on the basis of experimental data. Special attention is paid to the thermal conduction along a thin thermometer probe and to the self-heating of the probe. A new method for compensating the error due to the heat flow is presented. It is shown that the compensated results are in good agreement with results obtained with standard TPW cells. The determined differences were well within the estimated expanded uncertainty of 2 mK (k = 2). The heat flow effect was studied experimentally by controlling the temperature of the upper part of a PRT inserted in a mini-TPW cell. Also, the effect of different fillings of the measurement well of the cell was studied. Without the compensation, thin metal-sheathed PRTs (1.6 and 2.2 mm) indicated 3 to 9 mK differences between mini-TPW and standard TPW cells.

Internal energy distribution of peptides in electrospray ionization : ESI and collision‐induced dissociation spectra calculation

The internal energy of ions and the timescale play fundamental roles in mass spectrometry. The main objective of this study is to estimate and compare the internal energy distributions of different ions (different nature, degree of freedom 'DOF' and fragmentations) produced in an electrospray source (ESI) of a triple-quadrupole instrument (Quattro I Micromass). These measurements were performed using both the Survival Yield method (as proposed by De Pauw) and the MassKinetics software (kinetic model introduced by Vékey). The internal energy calibration is the preliminary step for ESI and collision-induced dissociation (CID) spectra calculation. meta-Methyl-benzylpyridinium ion and four protonated peptides (YGGFL, LDIFSDF, LDIFSDFR and RLDIFSDF) were produced using an electrospray source. These ions were used as thermometer probe compounds. Cone voltages (V(c)) were linearly correlated with the mean internal energy values (<E(int) >) carried by desolvated ions. These mean internal energy values seem to be slightly dependent on the size of the studied ion. ESI mass spectra and CID spectra were then simulated using the MassKinetics software to propose an empirical equation for the mean internal energy (<E(int) >) versus cone voltage (V(c)) for different source temperatures (T): < E(int) > = [405 x 10(-6) - 480 x 10(-9) (DOF)] V(c)T + E(therm)(T). In this equation, the E(therm)(T) parameter is the mean internal energy due to the source temperature at 0 V(c).

Winter Protection of Tree Ferns at the Royal Botanic Garden Edinburgh

Ten plants of six species of tree fern were trialled for frost hardiness during the winter of 2005/06 when they were planted outdoors in the ground of an interior courtyard at the Royal Botanic Garden Edinburgh. The species were Culcita macrocarpa, Cyathea dealbata, Cyathea dregei,Cyathea smithii, Dicksonia antarctica and Thyrsopteris elegans. An additional specimen of C. dregei was planted in the main garden. The apex region of each tree fern was fitted with an electric thermometer probe to record weekly minimum and maximum temperatures. These were compared with the air temperatures of the courtyard. For thermal insulation, the trunks and crowns of the three Cyathea species were encased in straw. The prostrate rhizomes of C. macrocarpa and T. elegans were covered respectively with leaf litter, straw and a polystyrene tile. As comparators, three trunked specimens of D. antarctica were given no winter wrapping, since previous experience had shown it to be unnecessary. All ten plants survived the winter of 2005/06 which was colder than average, and put out new growth the following spring. Fronds of D. antarctica and C. macrocarpa stayed green; the fronds of the other species were withered by the coldest exposures when the air temperature reached 4.7°C.Compared with the main botanic garden, the courtyard provided a relatively mild microclimate. It was on average 2.5 °C warmer than the air temperature measured in the screen of the main garden weather station, and 7.7°C warmer than the ‘grass’ temperature in the main garden, which went down to –13°C at its lowest. All tree fern apices registered sub-zero temperatures, the range in different plants being from –0.3 to –3.4°C. The apex regions did not get as cold as the surrounding air temperature, which ranged between 0.5 and 2.3°C. The three D. antarctica (without added insulation) had minimum apical temperatures in the same range as the species that were wrapped for the winter. The insulation effect in the apex regions was also shown by the weekly maximum temperatures, which on average were lower than those of the courtyard air maxima.In conclusion, the combination of the locally favourable microclimate of the courtyard, plus appropriate trunk and crown insulation provided for some species, allowed the planting outdoors, of tree ferns normally grown in Edinburgh under heated glass.

Thermostatic tissue platform for intravital microscopy: ‘the hanging drop’ model

Intravital microscopy imposes the particular problem of the combined control of the body temperature of the animal and the local temperature of the observed organ or tissues. We constructed and tested, in the rat ileum microcirculation preparation, a new organ-support platform. The platform consisted of an organ bath filled with physiological solution, and contained a suction tube, a superfusion tube, an intestine-support hand that was attached to a micromanipulator and a thermometer probe. To cover the intestine we used a cover glass plate with a plastic ring glued on its upper surface. After a routine procedure (anaesthesia, monitoring and surgery), the intestine segment (2-3 cm long) was gently exteriorized and placed on the 'hand' of the organ support. A small part of the intestine formed a small 'island' in the bath that was filled with physiological salt solution. The cover glass was secured in place. The physiological salt solution from the superfusion tube, which was pointed to the lower surface of the cover glass, formed a 'hanging drop'. The objective of the microscope was then immersed into distilled water that was formed by the cover glass plastic ring. The 'hanging drop' technique prevented any tissue quenching, ensured undisturbed microcirculation, provided for stable temperature and humidity, and permitted a clear visual field.

Laser Doppler scanning study of palmar skin perfusion for patients with hyperhidrosis before and after thoracic sympathectomy

Background Palmar hyperhidrosis is effectively treated by thoracic sympathectomy. Previous reports revealed that palmar skin temperature and perfusion increased on focal palmar regions after treatment. This study aimed to investigate the blood flow change over the whole palmar surface after the procedure. Methods Thirty patients with severe palmar hyperhidrosis were included for study. Each participant received measurement of palmar skin perfusion by a laser Doppler image scanner 1 day before and 1 day after surgery. Concomitantly, palmar skin temperature was recorded by a contact thermometer probe. One patient underwent intraoperative recording of palmar skin perfusion. Results Palmar skin perfusion and temperature increased significantly after thoracic sympathectomy. Intraoperative measurement performed for a patient showed a similar trend of increment of palmar skin blood flow. Conclusions The global skin perfusion of palms can be analyzed in real time by the laser Doppler image scanner. This technique could be useful for analysis of blood flow changes in other body surface regions after thoracic sympathectomy.

Performance characteristics of ultra-violet femtosecond laser ablation inductively coupled plasma mass spectrometry at ∼265 and ∼200 nm

The analytical figures of merit of ultra-violet femtosecond laser ablation inductively coupled plasma mass spectrometry (UV-fs-LA-ICP-MS) using the 3rd and 4th harmonics of Ti:Sapphire (∼265 and ∼200 nm, respectively) were explored. For this purpose, elemental ratios of aerosols produced by LA of silicate glass (SRM NIST 610) were studied under varying fluence conditions ranging from moderate values of 2 J cm−2 up to 30 J cm−2, taking into account e.g. laser-induced (66Zn/65Cu) and particle size-related (238U/232Th) phenomena. It could, for instance, be shown that signal ratios were less dependent on the wavelength or laser repetition rate chosen. Furthermore, fractionation indices defined using the temporal drift of elemental ratios over two equal parts of the acquired signal were subject to systematic changes for threshold-close fluences. As a consequence, corresponding 42Ca-normalized values were found to deviate by more than 20% from unity. In contrast, LA at higher fluences resulted in less pronounced discrepancies, falling below 5% even for the most critical elements such as 66Zn, 111Cd, and 208Pb. The complete suppression of particle size-related fractionation quantified on the basis of the 238U/232Th-system turned out to be highly consistent with the absence of μ-sized particles which were measured by optical particle counting (OPC). The relative fraction of particles >0.5 μm was determined to be less than 5%, independent on the wavelength, fluence, or laser repetition rate chosen. Moreover, our results indicate the occurrence of ICP-induced elemental fractionation during analysis due to an increased mass loading of the plasma source if medium or high fluences are applied. Using the 66Zn/65Cu-ratio as a thermometric probe, the change in plasma ionization temperature among low and high mass loading conditions was estimated to be −900 K. Nevertheless, UV-fs-LA-ICP-MS analysis of different matrices (silicate glass SRM NIST 610 and brass (Zn ∼20%)) performed within the high fluence range was found to enhance the accuracy for non-matrix-matched calibration. Evidence is given that the enhancement observed mainly depends upon the suppression of laser- and/or transport-induced fractionation.

Temperature along the Axillary Nerve during Radiofrequency-Induced Thermal Capsular Shrinkage

Background There have been reports of axillary nerve palsy after thermal capsular shrinkage with radiofrequency energy-generating devices. The exact cause of this is unknown. Hypothesis The temperature of the axillary nerve increases during shoulder capsular shrinkage at various degrees of shoulder abduction. Study Design Laboratory study. Methods Fifteen cadaveric shoulders had fiberoptic thermometer probes placed at various points along the axillary nerve and major branches under the capsule. The shoulders underwent thermal capsular shrinkage with a radiofrequency energy-inducing device at various positions of abduction. Results With the arm at the side, temperatures above 50°C (56°-61°C) were evident along the teres minor branch of the axillary nerve in 4 of 6 specimens. The increase in temperature was noted in the middle to posterior aspect of the inferior capsule. At 45° of abduction, 4 of 5 shoulders demonstrated increases in temperature greater or equal to 50°. Three of 4 shoulders tested at 90° of abduction revealed similar temperature increases. Conclusions The arthroscopic technique of thermal capsular shrinkage causes an increase in the temperature of the axillary nerve and its branches in 11 of 15 cadaveric specimens tested at various arm positions—particularly affected is the teres minor branch. Clinical Relevance Orthopaedic surgeons using the radiofrequency device for thermal capsular shrinkage need to be aware of the possible increase in temperature along the axillary nerve and its branches during this procedure. The clinical effect of this type of increase on the nerve is unknown.

Fluorescence decay characteristic of Tm-doped YAG crystal fiber for sensor applications, investigated from room temperature to 1400 °C

An yttrium aluminum garnet (YAG) crystal fiber with a thulium-doped end tip was specially grown by means of the laser heated pedestal growth approach and designed to be incorporated in a fiber-optic temperature probe. The fluorescence decay characteristics of the crystal fiber, including the temperature dependence of both the fluorescence lifetime and intensity, were comprehensively investigated. Experimental results indicated that the crystal fiber showed a monotonic relationship between the fluorescence lifetime and temperature with an average lifetime sensitivity of 3 μs °C over a wide temperature range, taking measurement from room temperature to 1200°C. Good stability (up to 1400°C) was observed with high repeatability of the fluorescence lifetime during the annealing process carried out on the fiber over this temperature range. The fiber was found to be an excellent candidate material to be used as a fluorescence decay-based fiber thermometer probe and the results are presented on its performance.

Hipertermia intracraneal no invasiva mediante la técnica de Transferencia Eléctrica Capacitiva -TEC- (*). Resultados de la termometría cerebral e intratumoral

The aim of this work is to present the results of thermic increase obtained at the brain and intratumoral levels through a non invasive technique -Electric Capacitive Transference- (ECT), developed in 1985 by Indiba. A review of the literature does not provide any reference of cerebral and intratumoral thermometry in real time with a non invasive technique of intracranial hyperthermia. In the 8 studied patients, the increases of temperature in the brain, ranged between 0.7 and 1.5 degrees C in relation to the depth of the thermometric probe and the incidence angle of the external electrode. Between tumoral and perilesional brain tissues, thermic increase was 0.3 to 0.7 degrees C greater at tumoral level. The observation that in no case the surrounding brain tissue registered a temperature over 39.2 degrees C supports the harmlessness of the technique regarding the potential damage to healthy brain tissue and seems to confirm previous data obtained in anatomopathological studies in animal experimentation performed in 1990, which showed an absence of lesions in tissues and organs. The greater and somewhat more prolonged thermic increase observed at tumoral level has been called the "greenhouse effect".

Infrared ear thermometry compared with rectal thermometry in children: a systematic review

Infrared ear thermometry is frequently used in children, because this is a quick method of taking temperature and the ear is easily accessible. Our aim was to evaluate agreement between temperature measured at the rectum and ear in children. We did a systematic review of studies comparing temperature measured at the rectum (the reference site) using mercury, electronic, or indwelling probe thermometers, with temperature measured at the ear (the test site) using infrared ear thermometers. Heterogeneity between studies was investigated by exploring subgroups according to the mode of the infrared ear thermometer. 44 studies containing 58 comparisons (5935 children) were eligible for inclusion in this review. Outcome data were available in reports from 12 comparisons (2312 [39%] children), and data on individual patients were obtained for a further 19 comparisons (2129 [36%] children). 31 comparisons (4441 [75%] children) were therefore included in the meta-analysis. The pooled mean temperature difference (rectal minus ear) was 0.29 degrees C (95% limits of agreement -0.74 to 1.32). We pooled data by ear device mode and the mean temperature differences were rectal mode 0.15 degrees C (-0.95 to 1.25), actual 0.70 degrees C (-0.20 to 1.60), core 0.25 degrees C (-0.78 to 1.27), oral 0.34 degrees C (-0.86 to 1.54), tympanic 0.62 degrees C (-0.40 to 1.64) and mode not stated 0.32 degrees C (-0.57 to 1.21). There was significant residual heterogeneity in both mean differences and sample SDs within the groups of ear device mode. Although the mean differences between rectal and ear temperature measurements were small, the wide limits of agreement mean that ear temperature is not a good approximation of rectal temperature, even when the ear thermometer is used in rectal mode. Our finding suggests that infrared ear thermometry does not show sufficient agreement with an established method of temperature measurement to be used in situations where body temperature needs to be measured with precision.

Characteristics of sapphire fiber connected with ruby sensor head for the fiber-optic thermometer applications

The fiber-optic thermometer probe, in which the sapphire fiber was connected mechanically with the ruby sensor head, has been fabricated and the performances of the probes are evaluated as compared with those using the silica fiber. The value of photoluminescence (PL) lifetime and its temperature coefficients for the ruby sensor head with sapphire fiber (t=3.9 ms and −9.9 μs/K) were slightly different from those using the silica fiber (τ=4.2 ms and −10.9 μs/K), even if the same ruby sensor head was used. These differences are found to be caused by the background PL due to residual impurities and/or defects in the sapphire fibers, which vary with the growth techniques of the fibers. The influence of the PL from the sapphire fiber on the temperature measurements can be reduced successfully using a modified lifetime calculation based on the curve fitting of the PL decay with double exponential equation. By using a modified lifetime calculation, the ruby sensor head with sapphire fiber can be used in the temperature measurement ranging from 270 to 670 K with ±1.5 K accuracy.

Temperature rise during reamed tibial nailing.

The current study determined the temperature rise during reamed tibial intramedullary nailing in vivo. Eighteen adult patients were studied. The tibial medullary canal diameter ranged from 8 to 11 mm and was reamed to at least 1.5 mm above the required nail diameter with AO reamers. Reaming of the medullary cavity ranged from 9 to 12 mm before nail insertion. Intraoperative monitoring of the heat produced during reaming of the medullary cavity was done by inserting two platinum resistance thermometer probes into the cortical bone at the short isthmic segment of the tibial shaft. The probes were connected to a data logger, and temperature readings were taken every 5 seconds during each reaming procedure. The mean tibial temperature before initiation of reaming was 35.6 degrees C (standard deviation, +/- 0.5 degrees), and peak temperatures recorded were from 36.1 degrees C to 51.6 degrees C. A direct correlation was observed between temperature elevation and amount of reaming. With reaming above 10 mm, tibias with a canal diameter of 8 mm showed a statistically higher temperature rise compared with tibias with a canal diameter of 9, 10, or 11 mm. No patients had intraoperative or postoperative complications related to skin or bone thermal necrosis, and bony healing progressed uneventfully. The small amount of reaming required to insert a nail into a normal 9-, 10-, or 11- mm tibial canal does not seem to produce a clinical problem. Reaming smaller canals (8 mm) to a larger size may induce a significant heating effect.

Optimization of the Probe Design for Nuclear Quadrupole Resonance Thermometry

A continuous-flow thermostat design for a nuclear quadrupole resonance thermometer probe is described. This design makes it possible to significantly decrease the length of the coaxial line connecting the inductance coil to the autodyne and to increase the signal-to-noise ratio. The thermostatting range of the working substance of the probe is 200–500 K. As a working substance of the nuclear quadrupole resonance thermometer, a powder of cuprous oxide (Cu2O) was used. The temperature measurement accuracy is ∼0.1 K.

An Alternative to Mercury Thermometers

This brief laboratory safety note describes a simple and inexpensive way to protect a metallic thermometer probe, thus allowing employment of digital thermometers and or digital temperature controllers in aggressive media.