Quantitative Measurement of Thermal Conductivity by SThM Technique: Measurements, Calibration Protocols and Uncertainty Evaluation

Thermal management is a key issue for the downsizing of electronic components in order to optimise their performance. These devices incorporate more and more nanostructured materials, such as thin films or nanowires, requiring measurement techniques suitable to characterise thermal properties at the nanoscale, such as Scanning Thermal Microscopy (SThM). In active mode, a hot thermoresistive probe scans the sample surface, and its electrical resistance R changes as a function of heat transfers between the probe and sample. This paper presents the measurement and calibration protocols developed to perform quantitative and traceable measurements of thermal conductivity k using the SThM technique, provided that the heat transfer conditions between calibration and measurement are identical, i.e., diffusive thermal regime for this study. Calibration samples with a known k measured at the macroscale are used to establish the calibration curve linking the variation of R to k. A complete assessment of uncertainty (influencing factors and computational techniques) is detailed for both the calibration parameters and the estimated k value. Outcome analysis shows that quantitative measurements of thermal conductivity with SThM (with an uncertainty value of 10%) are limited to materials with low thermal conductivity (k<10Wm−1K−1)

Micro et nanothermique - Méthodes de caractérisation et de mesure

National audienceLa dissipation de la chaleur et la gestion thermique sont des défis centraux dans divers domaines de la science et de la technologie et également des problèmes critiques pour la majorité des dernières générations de dispositifs électroniques.Suite à une introduction des différents mécanismes de transfert thermique aux micro et nano-échelles, cet article expose les techniques de caractérisation thermique actuellement dédiées à l’analyse de champs de température et à l’étude des propriétés thermiques aux échelles submicroniques. Il est également question de présenter les principaux défis et limites de ces techniques, ainsi que les tendances actuelles des développements en micro et nano-thermique

Uncertainty Assessment for Very High Temperature Thermal Diffusivity Measurements on Molybdenum, Tungsten and Isotropic Graphite

International audienceAbstract The French National Metrology Institute LNE has improved its homemade laser flash apparatus in order to perform accurate and reliable measurements of thermal diffusivity of homogeneous solid materials at very high temperature. The inductive furnace and the associated infrared (IR) detection systems have been modified and a specific procedure for the in situ calibration of the used radiation thermometers has been developed. This new configuration of the LNE’s diffusivimeter has been then applied for measuring the thermal diffusivity of molybdenum up to 2200 °C, tungsten up to 2400 °C and isotropic graphite up to 3000 °C. Uncertainties associated with these high temperature thermal diffusivity measurements have been assessed for the first time according to the principles of the “Guide to the Expression of Uncertainty in Measurement” (GUM). Detailed uncertainty budgets are here presented in the case of the isotropic graphite for measurements performed at 1000 °C, 2000 °C and 3000 °C. The relative expanded uncertainty (coverage factor k = 2) of the thermal diffusivity measurement is estimated to be between 3 % and 5 % in the whole temperature range for the three investigated refractory materials

Anti-Gb3 monoclonal antibody inhibits angiogenesis and tumor development.

Inhibiting the growth of tumor vasculature represents one of the relevant strategies against tumor progression. Between all the different pro-angiogenic molecular targets, plasma membrane glycosphingolipids have been under-investigated. In this present study, we explore the anti-angiogenic therapeutic advantage of a tumor immunotherapy targeting the globotriaosylceramide Gb3. In this purpose, a monoclonal antibody against Gb3, named 3E2 was developed and characterized. We first demonstrate that Gb3 is over-expressed in proliferative endothelial cells relative to quiescent cells. Then, we demonstrate that 3E2 inhibits endothelial cell proliferation in vitro by slowing endothelial cell proliferation and by increasing mitosis duration. Antibody 3E2 is further effective in inhibiting ex vivo angiogenesis in aorta ring assays. Moreover, 3E2 treatment inhibits NXS2 neuroblastoma development and liver metastases spreading in A/J mice. Immunohistology examination of the NXS2 metastases shows that only endothelial cells, but not cancer cells express Gb3. Finally, 3E2 treatment diminishes tumor vessels density, proving a specific therapeutic action of our monoclonal antibody to tumor vasculature. Our study demonstrates that Gb3 is a viable alternative target for immunotherapy and angiogenesis inhibition

Experimental measurement of heat transport property: Why is heat transportmodelling required for nanometrology?

National audienc

Inter-laboratory Comparison on Thermal Diffusivity Measurements by the Laser Flash Method at Ultra-high Temperature

An inter-laboratory comparison has been performed between seven participants on thermal diffusivity measurements by the laser flash method in the temperature range from 23 °C to 3000 °C. The main objective was to assess the variability and coherency of thermal diffusivity measurements performed at ultra-high temperatures at the European level. Three refractory materials (molybdenum, tungsten and isotropic graphite IG210) were selected for this inter-laboratory comparison, due to their high melting point. The disk-shaped specimens needed were machined from the same blocks of materials in order to reduce any potential scattering of results between participants due to inhomogeneity effects. The homogeneity of the sets of specimens was studied by the pilot laboratory (LNE) before launching the comparison process. Thermal diffusivity measurements were then carried out by the seven participants on the three materials during two successive thermal cycles up to the maximum temperatures that can be reached by the devices used. The analysis of results showed a good agreement between the participants for temperatures above 400 °C, with relative deviations within the uncertainties of measurement and lower than ± 4 % for molybdenum, ± 5 % for isotropic graphite and ± 9 % for tungsten. © 2023, The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature

Distribution of Gb3 in organs from C57Bl/6 mouse obtained after staining with Alexa568-conjuguated 3E2.

<p>Frozen healthy organs sections of 5 µm were hybridized with biotinylated 3E2 or its isotypic control, revealed by an Alexa 568-conjugated streptavidin and counterstained with DAPI. Pictures were observed under a confocal microscope (n = 3).</p>#<p>: High background.</p>*<p>: Lipofuscin autofluorescence.</p

Gb3 is over-expressed in proliferating endothelial cells.

<p>HMEC-1 were treated with medium containing respectively 15% serum, 0.1% serum and 0.1% serum with 1 µM S1P or its vehicle. A) Proliferation assay by ³H-thymidine incorporation 24 h after treatment. (n = 3; mean±SD; *p≤0.05). B) RT-Q PCR 24 h after treatment (n = 6; mean±SEM; ns: p<0.01). C) Gb3 expression detected by 3E2 after immuno-HPLC. D) Gb3-positive HMEC-1 determines by Facs using 10 µg/ml of 3E2 (n = 3). E). Gb3 site number determined by Scatchard analysis using 3E2.</p

3E2 antibody inhibits endothelial cell proliferation.

<p>HMEC-1 cells are tracked by videomicroscopy up to 24 h after treatment by 3E2 or isotypic control. A) Cell number per field in function of time. Histograms show the mean doubling time (n = 6 for IgM and n = 9 for 3E2, mean±SEM; *p<0.05). B) Microphotographs of representative fields of HMEC-1 in function of time. Magnification 10×. C) Number of mitosis summed every 6 h for 24 h (n = 5, mean±SEM; *p<0.05). D) Duration of the mitosis (n = 5, mean±SEM; *p<0.05). E) Cell death quantification detected by sub-G1 and hoechst assays from 3E2- or IgM-treated HMEC-1 (n = 3; mean±SD; ns: p>0.1).</p