Thermocouple Probe Research Articles

Feasibility of Real-Time Intraprocedural Temperature Control during Bone Metastasis Thermal Microwave Ablation: A Bicentric Retrospective Study

PurposeTo evaluate feasibility of using a thermocouple for temperature monitoring during microwave (MW) ablation of metastatic bone disease. Materials and MethodsThis retrospective study comprised 16 patients (8 men with mean age 63 y and 8 women with mean age 59 y) with 18 bone metastases treated with MW ablation using a thermocouple between March 2012 and October 2015. The mean maximum tumor size was 29.5 mm. MW ablation power was set between 15 W and 40 W and applied for 1–6 minutes. Thermocouple placements were as follows: epidural space (n = 7 cases), nerve roots (n = 9 cases), pleura (n = 1), and pericardium (n = 1). The procedure was considered technically successful when the MW and the thermocouple probes were accurately placed and thermoablation was initiated. Clinical success was defined as a 50% visual analog scale score decrease at 1 month as assessed by the operators. ResultsMean MW ablation time was 4.3 minutes with a mean energy of 30 W. Procedural success was 100%. In 16 cases with neural structure monitoring, temperature did not increase > 43°C. In 8 cases, MW ablation had to be discontinued because of temperature reaching 42°C. Efficacy of the procedure in regard to pain was achieved in 17 of 18 ablation sessions at 1 month. ConclusionsUse of a thermocouple during bone MW ablation is a feasible technique and may be a potentially useful tool to help avoid nontarget ablation surrounding tumors.

Caloric Loss Associated with Apheresis

A common complaint attributed to apheresis is chill and hunger. Most likely this is a result of heat loss when blood is externalized from the body. This energy loss has not been quantitated. To determine caloric loss we monitored temperature loss using sterilized Omega hypodermic type K thermocouple probes inserted 20cm from the subject into the draw and return line, the centrifuge chamber, and the body. Inlet, return, centrifuge, and body temperature were recorded at one minute intervals using an Omega RDXL4SD Data Logger. Either a 38oC water bath (sham subject, n=2 per device) or rhesus macaque (weight 5-7 kg) undergoing apheresis served as subject. By definition one calorie (4.2 joules) is the amount of energy required to heat 1mL of water 1oC. By knowing that the heat capacity of blood is 3.6 joules/mL, we can calculate calorie loss per procedure. A total of 15 small volume apheresis procedures were performed with the Fenwal CS3000 on 12 rhesus macaques using a modified single small volume chamber procedure (Donahue et al., BLOOD 87:1644-53, 1996), 7 procedures were performed on 3 rhesus macaques using a Spectra Optia, and 6 procedures were performed on 3 rhesus macaques using a Fenwal Amicus device. Using water, the average temperature difference between inlet and return line dropped logarithmically (R2>0.89) for all three instruments as flow rate was increased (Fig. 1). Similarly the calorie loss/min logarithmically increased (R2>0.89) (Fig. 2) as flow rate increased. For CS3000 rhesus apheresis procedures, the drop in temperature between draw and return lines was 8.7(SD 1.5) oC at a flow rate of approximately 11mL/min, 9.5(0.9) oC for the Optia at a flow rate of 10mL/min, and 10.3(1.2) oC for the Amicus at a flow rate of 11mL/min. This drop was not significantly different between instruments (p=0.10). Procedures did differ in the amount of blood processed. For the CS3000, the blood volume processed per procedure (1013(18) mL) was significantly less (p<0.001) than either the Optia (1425(201) mL) or Amicus (1473(36) mL). In addition, centrifuge chamber temperature differed between the CS3000 (33.1(1.6) oC) and the Optia (28(1.9) oC) or Amicus (26.0(1.0)oC) (p<0.001) as the CS3000 has a chamber heating element. For the CS3000, calorie loss per procedure was 7712(1823) calories, for the Optia 11827(1987) calories, and the Amicus 13199(1354) calories. The significant difference (p<0.001) in caloric loss between the CS3000 and the other instruments was due to the larger blood volume processed using the Optia and Amicus. To prevent calorie loss we developed a method using a 50oC heated water bath in which a segment of the return line (38 cm or more) was placed in the water bath to equilibrate draw and return line temperatures without altering extracorporeal blood volume. On performing this procedure, we successfully matched draw and return line temperatures. This report documents for the first time caloric loss during apheresis procedures. In addition, it introduces a method to limit such a loss. Although adults >50kg may tolerate apheresis-associated caloric loss with only mild to moderate symptoms, pediatric patients, small animals, and debilitated and aging subjects, may not. Here we demonstrate the extent of calorie loss and a means to prevent it. [Display omitted] [Display omitted] DisclosuresNo relevant conflicts of interest to declare.

Genetic ablation of phosphatidylcholine transfer protein/StarD2 in ob/ob mice improves glucose tolerance without increasing energy expenditure

ObjectivePhosphatidylcholine transfer protein (PC-TP; synonym StarD2) is highly expressed in liver and oxidative tissues. PC-TP promotes hepatic glucose production during fasting and aggravates glucose intolerance in high fat fed mice. However, because PC-TP also suppresses thermogenesis in brown adipose tissue (BAT), its direct contribution to obesity-associated diabetes in mice remains unclear. Here we examined the effects of genetic PC-TP ablation on glucose homeostasis in leptin-deficient ob/ob mice, which exhibit both diabetes and altered thermoregulation. Animals/MethodsMice lacking both PC-TP and leptin (Pctp−/−;ob/ob) were prepared by crossing Pctp−/− with ob/+ mice. Glucose homeostasis was assessed by standard assays, and energy expenditure was determined by indirect calorimetry using a comprehensive laboratory animal monitoring system, which also recorded physical activity and food intake. Body composition was determined by NMR and hepatic lipids by enzymatic assays. Core body temperature was measured using a rectal thermocouple probe. ResultsPctp−/−;ob/ob mice demonstrated improved glucose homeostasis, as evidenced by markedly improved glucose and pyruvate tolerance tests, without changes in insulin tolerance. However, there were no differences in EE at any ambient temperature. There were also no effects of PC-TP expression on physical activity, food intake or core body temperature. ConclusionsImproved glucose tolerance in Pctp−/−;ob/ob mice in the absence of increases in energy expenditure or core body temperature indicates a direct pathogenic role for PC-TP in diabetes in leptin deficient mice.

The empirical definition of total emissivity of modern superthin liquid composite thermal insulators

Modern world trends in the field of energy and mineral resources preservation policy involves the need for a more cost-efficient use of the Earth's natural resources, including in the field of construction industry. Using insulation modern materials would largely solve this problem. The acceptability appraisal of various advanced heat-insulating blankets is a crucial task, which requires experimental verification of total emissivity empirical definition of modern super-thin liquid composite thermal insulators and their real value definition. Method of investigation is as follows: an empirical definition of blankets emissivity using the proposed laboratory equipment, which comprises a system of "gray" bodies, thermocouple probe and a source of continuous heat flux. Total emissivity of modern super-thin liquid composite thermal insulators is experimentally determined. It amounted e = 0.89 for sample # 1, and e = 0.87 for sample # 2 at a temperature of 35-65 °C. It was found that the actual emissivity of the samples was higher than it had been declared.

Assessing the reliability of thermography to infer internal body temperatures of lizards

For many years lizard thermal ecology studies have relied on the use of contact thermometry to obtain internal body temperature (Tb) of the animals. However, with progressing technology, an interest grew in using new, less invasive methods, such as InfraRed (IR) pyrometry and thermography, to infer Tb of reptiles. Nonetheless few studies have tested the reliability of these new tools. The present study tested the use of IR cameras as a non-invasive tool to infer Tb of lizards, using three differently body-sized lacertid species (Podarcis virescens, Lacerta schreiberi and Timon lepidus). Given the occurrence of regional heterothermy, we pairwise compared thermography readings of six body parts (snout, eye, head, dorsal, hind limb, tail base) to cloacal temperature (measured by a thermometer-associated thermocouple probe) commonly employed to measure Tb in field and lab studies. The results showed moderate to strong correlations (R2=0.84–0.99) between all body parts and cloacal temperature. However, despite the readings on the tail base showed the strongest correlation in all three species, it was the eye where the absolute values and pattern of temperature change most consistently followed the cloacal measurements. Hence, we concluded that the eye would be the body location whose IR camera readings more closely approximate that of the animal's internal environment. Alternatively, other body parts can be used, provided that a careful calibration is carried out. We provide guidelines for future research using thermography to infer Tb of lizards.

Evolution of acoustic microscopy in the commercial marketplace

The promise of Acoustic Microscopy from the 1970s,—to image features and structures of samples from a micromechanical aspect—has found a few niche markets in industry, and, in particular, defect detection in manufactured products. The hope for its widespread application in medicine and pathology has not yet been reached in the commercial market, though there are several pockets of significant biomedical research that employ acoustic microscopy methods. This paper will give this author’s perspective on the field from his 40 years of experience at Sonoscan, Inc., a company originally founded to explore commercial applications, and whose primary activities have found to be serving the semiconductor and microelectronics industries. Based on the original Ultrasonic Absorption Microscope paper by Dunn and Fry in 1959, the early commercial technique substituted a scanning laser as an acoustic detector for their thermocouple probe to produce two dimensional acoustic images.

A new approach to selective brain cooling by a Ranque-Hilsch vortex tube.

BackgroundTarget temperature management is the single most effective intervention and the gold standard in post-resuscitation care today. However, cooling the whole body below 33–34 °C can cause severe complications. Therefore, developing a selective brain cooling (SBC) approach which can be initiated early to induce rapid cooling and maintain the target temperature over 12–24 h before slowly rewarming brain temperature by itself alone would be advantageous. Vortex tubes are simple mechanical devices generating cold air from a stream of compressed air without applied chemical or energy. This study investigated whether blowing cooled air from a vortex tube into the nasal cavities is safe and effective to selectively reduce and maintain before slowly rewarming brain temperature back to normal temperature.MethodsExperiments were conducted on ten juvenile pigs. Body temperature was measured using an esophageal and a rectal temperature probe while brain temperature with an intraparenchymal thermocouple probe. Cerebral blood flow (CBF) was measured with CT perfusion.ResultsBrain temperature dropped below 34 °C within 30–40 min while a brain-esophageal temperature difference greater than 3 °C was maintained over 6 h. There was no evidence of nasal or nasopharynx mucosal swelling, necrosis, or hemorrhage on MRI examination. CBF first decreased and then stabilized together with brain temperature before increasing to the baseline level during rewarming.ConclusionsSBC was accomplished by blowing cold air from a vortex tube into the nasal cavities. Due to its portability, the method can be used continuously in resuscitated patients in both in- and out-of-hospital situations without interruption.

Brain heating induced by near-infrared lasers during multiphoton microscopy.

Two-photon imaging and optogenetic stimulation rely on high illumination powers, particularly for state-of-the-art applications that target deeper structures, achieve faster measurements, or probe larger brain areas. However, little information is available on heating and resulting damage induced by high-power illumination in the brain. In the current study we used thermocouple probes and quantum dot nanothermometers to measure temperature changes induced by two-photon microscopy in the neocortex of awake and anaesthetized mice. We characterized heating as a function of wavelength, exposure time, and distance from the center of illumination. Although total power is highest near the surface of the brain, heating was most severe hundreds of micrometers below the focal plane, due to heat dissipation through the cranial window. Continuous illumination of a 1-mm(2) area produced a peak temperature increase of ∼1.8°C/100 mW. Continuous illumination with powers above 250 mW induced lasting damage, detected with immunohistochemistry against Iba1, glial fibrillary acidic protein, heat shock proteins, and activated caspase-3. Higher powers were usable in experiments with limited duty ratios, suggesting an approach to mitigate damage in high-power microscopy experiments.

Gallbladder Cryoablation: Proof of Concept in a Swine Model for a Percutaneous Alternative to Cholecystectomy.

To investigate the feasibility of percutaneous gallbladder cryoablation (GBC) under CT guidance in a swine model with histopathologic correlation. Institutional Animal Care and Use Committee approval was obtained for this study protocol. Five pigs underwent GBC. Under CT guidance, 3-4 cryoprobes were positioned percutaneously at the gallbladder margins. Thermocouple probes were placed percutaneously at the gallbladder fundus, neck, free wall, and gallbladder fossa. Two freeze-thaw cycles ranging from 10 to 26min were performed. The subjects were sacrificed 5h after cryoablation. The gallbladder and bile ducts were resected, stained, and examined microscopically. GBC was completed in all subjects. A 10-mm ablation margin was achieved beyond all gallbladder walls. Thermocouple probes reached at least -20°C. Intra-procedural body temperature decreased to a minimum of 35°C but recovered after the procedure. Intra- and post-procedural vital signs otherwise remained within physiologic parameters. Non-target ablation occurred in the stomach and colon of the first two subjects. Histology demonstrated complete denudation of the gallbladder epithelium, hemorrhage, and edema within the muscularis layer, and preservation of the microscopic architecture of the common bile duct in all cases. Percutaneous gallbladder cryoablation is feasible, with adequate ablation margins obtained and histologic changes demonstrating transmural necrosis. Adjacent structures included in the ablation may require conservative ablation zones, hydrodissection, or continuous saline lavage.

Preliminary study to the temperatures of the thermocouple probes affected by the environment of heated walls

Measuring of the total temperatures of the flowing medium is one of the pivotal points in the development when a new compressor stages are tested. Measurements conducted on the test compressor indicated that in the specific cases the measured temperature can be affected by the temperature of the walls which hold thermocouple probe. By implication of this observed fact, the preliminary study about this phenomenon was investigated. It was considered the influence of the heat conduction in the body of the probe and in the thermocouples. The main aim of the study was to examine the properties and the behaviour of the thermocouple probes in various working regimes. The preliminary study was focused on the development of the tools that can be used for complex solution of the problem by using of measured data. The results of this study might help to correct measured data in the case of skewed measurements affected by surroundings of the thermocouple probes.

An in-vitro study to compare the temperature rise in the pulp chamber by direct method using three different provisional restorative materials

Statement of Problem:The provisional restorative materials in fixed prosthodontics are basically bis-GMA resins which releases exothermic temperature while polymerization which can damage the pulp. Intrapulpal temperature exceeding 42.5°C found to result in irreversible damage to the pulp. The remaining thickness of dentine after tooth preparation control the conduction of heat released by the resins.Purpose:(1) To quantify the temperature changes in the pulp chamber using different provisional restorative materials. (2) To evaluate the peak temperature time of different materials used. (3) To compare the intrapulpal temperature changes with a variation in the width of the finish line.Methodology:Two intact mandibular molars were selected and designated as Specimen A and B. Tooth preparation was done to prepare a finish line of 1.2 mm and 1 mm width, respectively. Three provisional restorative materials were considered and they were grouped as Group I-Cool temp, Group II-Protemp-4, Group III-Integrity. A J thermocouple probe was placed into the pulp chamber to determine the rise in temperature. The temperature was recorded during polymerization at 30-s intervals until the peak temperature was reached. The same procedure was repeated for fabricating remaining provisional crowns. A total of 45 provisional crowns were fabricated for each specimen.Results:Kruskal–Wallis test revealed that there was a significant difference in the temperature changes associated with the provisional restorative materials used. All the three provisional restorative materials were compared for 1.2 mm and 1 mm wide finish line. Integrity produced the highest temperature rise and the maximum temperature recorded was 40.2°C in 1.2 mm wide finish line. However, for a 1 mm wide finish line, Protemp-4 produced the highest temperature rise and the maximum temperature recorded was 40.3°C. It was observed that peak temperatures with Specimen B were more when compared with Specimen A.Conclusion:Cool temp showed least temperature rise in the pulp chamber. The order of rise in intrapulpal temperature in tested provisional materials using direct technique would be Cool temp, Integrity, and Protemp-4.

Investigation of the effects of quarl and initial conditions on swirling non-premixed methane flames: Flow field, temperature, and species distributions

Detailed measurements are presented of the turbulent flow field, gas species concentrations and temperature field in a non-premixed methane swirl flame. Attention is given to the effect of the quarl geometry on the flame structure and emission characteristics due to its importance in gas turbine and industrial burner applications. Two different quarls were fitted to the burner exit, one a straight quarl and the other a diverging quarl of 15° half cone angle. Stereoscopic Particle Image Velocimetry (SPIV) was applied to obtain the three components of the instantaneous velocity on a vertical plane immediately downstream of the quarl exit. Temperature and gaseous species measurements were made both inside and downstream of the quarls, using a fine wire thermocouple and sampling probe, respectively. This work provides experimental verification by complementary techniques. The results showed that although the main flame structures were governed by the swirl motion imparted to the air stream, the quarl geometry, fuel loading and air loading also had a significant effect on the flow pattern, turbulence intensity, mixture formation, temperature distribution, emissions and flame stabilization. Particularly, in the case of the straight quarl flame, the flow pattern leads to strong, rapid mixing and reduces the residence time for NO formation within the internal recirculation zone (IRZ). However, for the diverging quarl flames, the recirculation zone is shifted radially outward, and the turbulent interaction between the central fuel jet and the internal recirculation zone IRZ induces another small vortex between these two flow features. Less mixing near the diverging quarl exit is observed, with a higher concentration of NO and CO in the post-combustion zone. The instantaneous flow field for both flames showed the existence of small scale vortical structure near the shear layers which were not apparent in the time averaged flow field. These structures, along with high levels of turbulence present in the shear layer, result in the enhancement of the mixing, especially with straight quarl. This article outlines results that yield deeper insight into the combustion of swirling flames stabilized within the quarl and to establish an experimental data base for modelers.

Infrared Thermal Imaging to Collect Quantitative Surface Temperatures From Mice In Unilateral Limb Heating Study

Infrared thermal imaging is a useful strategy for generating temperature data in biological research. The noninvasive approach enables surface temperature measurements that are more accurate than standard thermocouple probes. Our lab developed a unilateral heating model to induce limb elongation in growing mice. We have shown that targeted heating for only 40 minutes per day enhances limb lengthening on the heat-treated side. The heat-treated hindlimb was 37% warmer (11C) than the non-treated limb during treatments. In this study we used thermal imaging to determine the extent to which heat is retained post-treatment. We tested the hypothesis that a temperature differential would persist for at least 60 minutes post-heating. In a pilot study, we captured thermal images of 5-week old female mice (N=6) at 30- and 60-minute time points after a single initial heating session. Conscious mice were briefly restrained to minimally disturb their physiology. Preliminary thermography data for N= 3 mice showed the heat-treated limb remained 3.3% warmer (0.8C) than the non-treated limb at 30 minutes, and 1.5% warmer (0.6C) at 60 minutes. Our ongoing work examines whether temperatures remain permanently elevated after multiple days of heating. These results will be important for understanding the impact of heat therapy by quantifying the extended period in which the limbs maintain warmer temperatures after daily treatments. Supported by ASBMR GAP, WV-NASA, UK-CCTS (NIH UL1TR000117), and NIH/NIAMS R15AR067451-01

A simple and inexpensive method for determining cold sensitivity and adaptation in mice.

Cold hypersensitivity is a serious clinical problem, affecting a broad subset of patients and causing significant decreases in quality of life. The cold plantar assay allows the objective and inexpensive assessment of cold sensitivity in mice, and can quantify both analgesia and hypersensitivity. Mice are acclimated on a glass plate, and a compressed dry ice pellet is held against the glass surface underneath the hindpaw. The latency to withdrawal from the cooling glass is used as a measure of cold sensitivity. Cold sensation is also important for survival in regions with seasonal temperature shifts, and in order to maintain sensitivity animals must be able to adjust their thermal response thresholds to match the ambient temperature. The Cold Plantar Assay (CPA) also allows the study of adaptation to changes in ambient temperature by testing the cold sensitivity of mice at temperatures ranging from 30 °C to 5 °C. Mice are acclimated as described above, but the glass plate is cooled to the desired starting temperature using aluminum boxes (or aluminum foil packets) filled with hot water, wet ice, or dry ice. The temperature of the plate is measured at the center using a filament T-type thermocouple probe. Once the plate has reached the desired starting temperature, the animals are tested as described above. This assay allows testing of mice at temperatures ranging from innocuous to noxious. The CPA yields unambiguous and consistent behavioral responses in uninjured mice and can be used to quantify both hypersensitivity and analgesia. This protocol describes how to use the CPA to measure cold hypersensitivity, analgesia, and adaptation in mice.

Fiber tip-based electron source

The authors report on the first experimental characterization of a fiber tip-based electron source, where electron emission can be triggered by both electric field and optical excitation. Our approach consists of coating the open aperture of a commercial 100 nm apex size near-field scanning optical microscopy fiber tip with a 10 nm thick tungsten (W) layer, which is back-illuminated by a 405 nm continuous-wave laser beam in the presence of an extraction electric field. Despite the very low optical transmission of the fiber due to the subwavelength aperture size, measurements show a clearly enhanced emission when photoexciting the W layer with respect to pure field emission. The emission response time is slower than the optical trigger time, suggesting that thermal effects are predominant in the studied regime. To back up this hypothesis, the authors fabricated a nanometric thermocouple probe based on a Pt/Au junction and measured the temporal response of the tip temperature. The measured switch-on time for the tip temperature is consistent with the switch-on time of the optically enhanced electron emission.

Comparison of magnetic resonance concentration measurements in water to temperature measurements in compressible air flows

Magnetic resonance imaging (MRI) measurements in liquid flows provide highly detailed 3D mean velocity and concentration data in complex turbulent mixing flow applications. The scalar transport analogy is applied to infer the mean temperature distribution in high speed gas flows directly from the MRI concentration measurements in liquid. Compressibility effects on turbulent mixing are known to be weak for simple flows at high subsonic Mach number, and it was not known if this would hold in more complex flows characteristic of practical applications. Furthermore, the MRI measurements are often done at lower Reynolds number than the compressible application, although both are generally done in fully turbulent flows. The hypothesis is that the conclusions from MRI measurements performed in water are transferable to high subsonic Mach number applications. The present experiment is designed to compare stagnation temperature measurements in high speed airflow (M = 0.7) to concentration measurements in an identical water flow apparatus. The flow configuration was a low aspect ratio wall jet with a thick splitter plate producing a 3D complex downstream flow mixing the wall-jet fluid with the mainstream flow. The three-dimensional velocity field is documented using magnetic resonance velocimetry in the water experiment, and the mixing is quantified by measuring the mean concentration distribution of wall-jet fluid marked with dissolved copper sulfate. The airflow experiments are operated with a temperature difference between the main stream and the wall jet. Profiles of the stagnation temperature are measured with a shielded thermocouple probe. The results show excellent agreement between normalized temperature and concentration profiles after correction of the temperature measurements for the effects of energy separation. The agreement is within 1 % near the edges of the mixing layer, which suggests that the mixing characteristics of the large scale turbulence structures are the same in the two flows.

Embryo vitrification using a novel semi-automated closed system yields in vitro outcomes equivalent to the manual Cryotop method.

Can the equilibration steps prior to embryo vitrification be automated? We have developed the 'Gavi' system which automatically performs equilibration steps before closed system vitrification on up to four embryos at a time and gives in vitro outcomes equivalent to the manual Cryotop method. Embryo cryopreservation is an essential component of a successful assisted reproduction clinic, with vitrification providing excellent embryo survival and pregnancy outcomes. However, vitrification is a manual, labour-intensive and highly skilled procedure, and results can vary between embryologists and clinics. A closed system whereby the embryo does not come in direct contact with liquid nitrogen is preferred by many clinics and is a regulatory requirement in some countries. The Gavi system, an automation instrument with a novel closed system device, was used to equilibrate embryos prior to vitrification. Outcomes for embryos automatically processed with the Gavi system were compared with those processed with the manual Cryotop method and with fresh (non-vitrified) controls. The efficacy of the Gavi system (Alpha model) was assessed for mouse (Quackenbush Swiss and F1 C57BL/6J x CBA) zygotes, cleavage stage embryos and blastocysts, and for donated human vitrified-warmed blastocysts. The main outcomes assessed included recovery, survival and in vitro embryo development after vitrification-warming. Cooling and warming rates were measured using a thermocouple probe. Mouse embryos vitrified after processing with the automated Gavi system achieved equivalent in vitro outcomes to that of Cryotop controls. For example, for mouse blastocysts both the Gavi system (n = 176) and manual Cryotop method (n = 172) gave a 99% recovery rate, of which 54 and 50%, respectively, progressed to fully hatched blastocysts 48 h after warming. The outcomes for human blastocysts processed with the Gavi system (n = 23) were also equivalent to Cryotop controls (n = 13) including 100% recovery for both groups, of which 17 and 15%, respectively, progressed to fully hatched blastocysts 48 h after warming. The cooling and warming rates achieved with the Gavi system were 14 136°C/min and 11 239°C/min, respectively. Testing of the Gavi system described here was limited to in vitro development of embryos from two mouse strains and a limited number of human embryos. Validation of Gavi system advanced production models is now required to confirm the success of semi-automated vitrification, including clinical evaluation of pregnancy outcomes from the transfer of Gavi vitrified-warmed human embryos. The Gavi system has the potential to revolutionize and standardize vitrification of embryos and oocytes. The success of the Gavi system shows that it is possible to semi-automate complicated labour-intensive ART methods and processes, and opens up the possibility for further improvements in clinical outcomes and efficiencies in the ART clinic. This study was funded by Genea Ltd. S.B., N.M.T., T.T.P., S.J.M., M.C.B. and T.S. are shareholders of Genea Ltd. E.V., C.H., C.L., S.R.L. and S.M.D. are shareholders of Planet Innovation Pty Ltd. The remaining authors are employees of either Genea Ltd. or Planet Innovation Pty Ltd.

Uncertainty analysis for common Seebeck and electrical resistivity measurement systems.

This work establishes the level of uncertainty for electrical measurements commonly made on thermoelectric samples. The analysis targets measurement systems based on the four probe method. Sources of uncertainty for both electrical resistivity and Seebeck coefficient were identified and evaluated. Included are reasonable estimates on the magnitude of each source, and cumulative propagation of error. Uncertainty for the Seebeck coefficient includes the cold-finger effect which has been quantified with thermal finite element analysis. The cold-finger effect, which is a result of parasitic heat transfer down the thermocouple probes, leads to an asymmetric over-estimation of the Seebeck coefficient. A silicon germanium thermoelectric sample has been characterized to provide an understanding of the total measurement uncertainty. The electrical resistivity was determined to contain uncertainty of ±7.0% across any measurement temperature. The Seebeck coefficient of the system is +1.0%/-13.1% at high temperature and ±1.0% near room temperature. The power factor has a combined uncertainty of +7.3%/-27.0% at high temperature and ±7.5% near room temperature. These ranges are calculated to be typical values for a general four probe Seebeck and resistivity measurement configuration.

Toward Online Adaptive Hyperthermia Treatment Planning: Correlation Between Measured and Simulated Specific Absorption Rate Changes Caused by Phase Steering in Patients

Hyperthermia is the clinical application of heat, in which tumor temperatures are raised to 40°C to 45°C. This proven radiation and chemosensitizer significantly improves clinical outcome for several tumor sites. Earlier studies of the use of pre-treatment planning for hyperthermia showed good qualitative but disappointing quantitative reliability. The purpose of this study was to investigate whether hyperthermia treatment planning (HTP) can be used more reliably for online adaptive treatment planning during locoregional hyperthermia treatments. This study included 78 treatment sessions for 15 patients with non-muscle-invasive bladder cancer. At the start of treatments, temperature rise measurements were performed with 3 different antenna settings optimized for each patient, from which the absorbed power (specific absorption rate [SAR]) was derived. HTP was performed based on a computed tomography (CT) scan in treatment position with the bladder catheter in situ. The SAR along the thermocouple tracks was extracted from the simulated SAR distributions. Correlations between measured and simulated (average) SAR values were determined. To evaluate phase steering, correlations between the changes in simulated and measured SAR values averaged over the thermocouple probe were determined for all 3 combinations of antenna settings. For 42% of the individual treatment sessions, the correlation coefficient between measured and simulated SAR profiles was higher than 0.5, whereas 58% showed a weak correlation (R of <0.5). The overall correlation coefficient between measured and simulated average SAR was weak (R=0.31; P<.001). The measured and simulated changes in average SAR after adapting antenna settings correlated much better (R=0.70; P<.001). The ratio between the measured and simulated quotients of maximum and average SARs was 1.03 ± 0.26 (mean ± SD), indicating that HTP can also correctly predict the relative amplitude of SAR peaks. HTP can correctly predict SAR changes after adapting antenna settings during hyperthermia treatments. This allows online adaptive treatment planning, assisting the operator in determining antenna settings resulting in increased tumor temperatures.

A simple method for building materials thermophysical properties estimation

This article presents a light and easy to use method for simultaneous determination of thermal conductivity and volumetric heat capacity of a construction material without any control of boundary conditions. The material to be characterized is placed between two layers of materials with known thermophysical properties. Thermocouple probes are placed at the different interfaces and record the variations in temperature when the whole multilayer is subjected to stimulation. An inverse method based on a numerical model allows us to simultaneously identify the unknown thermal properties. This method was tested respectively on samples of polyvinyl chloride, expanded polystyrene, plaster and concrete.