Thermoreflectance Measurement of Temperature and Thermal Resistance of Thin Film Gold

To improve performance and reliability of integrated circuits, accurate knowledge of thermal transport properties must be possessed. In particular, reduced dimensions increase boundary scattering and the significance of thermal contact resistance. A thermoreflectance measurement can be used with a valid heat transport model to experimentally quantify the contact thermal resistance of thin film interconnects. In the current work, a quasi-steady state thermoreflectance measurement is used to determine the temperature distribution of a thin film gold interconnect (100 nm) undergoing Joule heating. By comparing the data to a heat transport model accounting for thermal diffusion, dissipation, and Joule heating, a measure of the thermal dissipation or overall thermal resistance of unit area is obtained. The gold film to substrate overall thermal resistance of unit area beneath the wide lead (10 lm) and narrow line (1 lm) of the interconnect are 1.64 Â 10 À6 m 2 K=W and 5.94 Â 10 À6 m 2 K=W, respectively. The thermal resistance of unit area measurements is comparable with published results based on a pump-probe thermoreflectance measurement

Thermoreflectance small scale temperature measurement under ambient conditions

Paper presented at the 9th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Malta, 16-18 July, 2012.dc201

A Multispecialty Evaluation of Thiel Cadavers for Surgical Training

Background: Changes in UK legislation allow for surgical procedures to be performed on cadavers. The aim of this study was to assess Thiel cadavers as high-fidelity simulators and to examine their suitability for surgical training. Methods: Surgeons from various specialties were invited to attend a 1 day dissection workshop using Thiel cadavers. The surgeons completed a baseline questionnaire on cadaveric simulation. At the end of the workshop, they completed a similar questionnaire based on their experience with Thiel cadavers. Comparing the answers in the pre- and post-workshop questionnaires assessed whether using Thiel cadavers had changed the surgeons’ opinions of cadaveric simulation. Results: According to the 27 participants, simulation is important for surgical training and a full-procedure model is beneficial for all levels of training. Currently, there is dissatisfaction with existing models and a need for high-fidelity alternatives. After the workshop, surgeons concluded that Thiel cadavers are suitable for surgical simulation (p = 0.015). Thiel were found to be realistic (p < 0.001) to have reduced odour (p = 0.002) and be more cost-effective (p = 0.003). Ethical constraints were considered to be small. Conclusion: Thiel cadavers are suitable for training in most surgical specialties

3D Hepatic Cultures Simultaneously Maintain Primary Hepatocyte and Liver Sinusoidal Endothelial Cell Phenotypes

Developing in vitro engineered hepatic tissues that exhibit stable phenotype is a major challenge in the field of hepatic tissue engineering. However, the rapid dedifferentiation of hepatic parenchymal (hepatocytes) and non-parenchymal (liver sinusoidal endothelial, LSEC) cell types when removed from their natural environment in vivo remains a major obstacle. The primary goal of this study was to demonstrate that hepatic cells cultured in layered architectures could preserve or potentially enhance liver-specific behavior of both cell types. Primary rat hepatocytes and rat LSECs (rLSECs) were cultured in a layered three-dimensional (3D) configuration. The cell layers were separated by a chitosan-hyaluronic acid polyelectrolyte multilayer (PEM), which served to mimic the Space of Disse. Hepatocytes and rLSECs exhibited several key phenotypic characteristics over a twelve day culture period. Immunostaining for the sinusoidal endothelial 1 antibody (SE-1) demonstrated that rLSECs cultured in the 3D hepatic model maintained this unique feature over twelve days. In contrast, rLSECs cultured in monolayers lost their phenotype within three days. The unique stratified structure of the 3D culture resulted in enhanced heterotypic cell-cell interactions, which led to improvements in hepatocyte functions. Albumin production increased three to six fold in the rLSEC-PEM-Hepatocyte cultures. Only rLSEC-PEM-Hepatocyte cultures exhibited increasing CYP1A1/2 and CYP3A activity. Well-defined bile canaliculi were observed only in the rLSEC-PEM-Hepatocyte cultures. Together, these data suggest that rLSEC-PEM-Hepatocyte cultures are highly suitable models to monitor the transformation of toxins in the liver and their transport out of this organ. In summary, these results indicate that the layered rLSEC-PEM-hepatocyte model, which recapitulates key features of hepatic sinusoids, is a potentially powerful medium for obtaining comprehensive knowledge on liver metabolism, detoxification and signaling pathways in vitro

Unusual presentation of Lynch Syndrome

Lynch Syndrome/HNPCC is a syndrome of cancer predisposition linked to inherited mutations of genes participating in post-replicative DNA mismatch repair (MMR). The spectrum of cancer associated with Lynch Syndrome includes tumours of the colorectum, endometrium, ovary, upper gastrointestinal tract and the urothelium although other cancers are rarely described. We describe a family of Lynch Syndrome with an hMLH1 mutation, that harbours an unusual tumour spectrum and its diagnostic and management challenges

Thermoreflectance Measurement of Temperature and Thermal Resistance of Thin Film Gold

To improve performance and reliability of integrated circuits, accurate knowledge of thermal transport properties must be possessed. In particular, reduced dimensions increase boundary scattering and the significance of thermal contact resistance. A thermoreflectance measurement can be used with a valid heat transport model to experimentally quantify the contact thermal resistance of thin film interconnects. In the current work, a quasi-steady state thermoreflectance measurement is used to determine the temperature distribution of a thin film gold interconnect (100 nm) undergoing Joule heating. By comparing the data to a heat transport model accounting for thermal diffusion, dissipation, and Joule heating, a measure of the thermal dissipation or overall thermal resistance of unit area is obtained. The gold film to substrate overall thermal resistance of unit area beneath the wide lead (10 μm) and narrow line (1 μm) of the interconnect are 1.64 × 10−6 m2 K/W and 5.94 × 10−6 m2 K/W, respectively. The thermal resistance of unit area measurements is comparable with published results based on a pump-probe thermoreflectance measurement

Diffraction model for thermoreflectance data

Thermoreflectance imaging provides the capability to map temperature spatially on the submicrometer scale by using a light source and CCD camera for data acquisition. The ability to achieve such spatial resolution and observe detailed features is influenced by optical diffraction. By combining diffraction from both the sample and substrate, a model is developed to determine the intensity of the thermoreflectance signal. This model takes into account the effective optical distance, sample width, wavelength, signal phase shift, and reflectance intensity, while showing qualitative and quantitative agreement with experimental thermoreflectance images from 1 and 10 μm wide gold lines at two wavelengths