Thickness-dependent thermal properties of amorphous insulating thin films measured by photoreflectance microscopy

In this work, we report on the measurement of the thermal conductivity of thin insulating films of SiO2 obtained by thermal oxidation, and Al2O3 grown by atomic layer deposition (ALD), both on Si wafers. We used photoreflectance microscopy to determine the thermal properties of the films as a function of thickness in the 2 nm to 1000 nm range. The effective thermal conductivity of the Al2O3 layer is shown to decrease with thickness down to 70% for the thinnest layers. The data were analyzed upon considering that the change in the effective thermal conductivity corresponds to an intrinsic thermal conductivity associated to an additional interfacial thermal resistance. The intrinsic conductivity and interfacial thermal resistance of SiO2 were found to be equal to 0.95 W/m·K and 5.1 × 10− 9 m2K/W respectively; those of Al2O3 were found to be 1.56 W/m·K and 4.3 × 10− 9 m2K/W

L’espace public entre mythe, imaginaire et culture

L'aménagement fait souvent appel à l'idée d'espace public, dont la portée sociale et politique demeure toutefois très discutée. Or une approche géographique peut aider à clarifier les aspects qui conditionnent son utilisation. On note d'abord que l'idée d'espace public s'inscrit sur un fond mythique porté par les idées de modernité, de justice, de démocratie, de rationalité et de sujet. Mais l'espace public ne fonctionne pas sur le mode du mythe, car il repose sur des normes et des règles qui mobilisent la rationalité du sujet. Il n'est pas pour autant un espace sans qualifications matérielles, sociales ni culturelles. Au contraire, il constitue un lieu, à la fois matériel et immatériel, qui fait aussi appel à l'imaginaire et à l'activité narrative du sujet.Urban and regional planning is frequently making use of the idea of public space; but, its actual social and political impact is very much debated. A geographical approach can help in clarifying the major aspects which are constraining its use. First, we note that the idea of public space rests on a set of myths which are related to the ideas of modernity, justice, democracy, rationality and the self. However, public space does not operate according to mythical modalities, because it requires norms and rules which draw on the rationality of the subject. Furthermore, it is not a space without material, social or cultural characteristics. On the contrary, it is a place which is both material and immaterial and which draws on imagination and on the narrative activity of the subject

Temperature Measurement of Microsystems by Scanning Thermal Microscopy

Submitted on behalf of EDA Publishing Association (http://irevues.inist.fr/handle/2042/5920)International audienceSurface temperature measurements were performed with a Scanning Thermal Microscope. We aim at proving an eventual sub-micrometric resolution of this metrology when using a wollaston wire probe of micrometric size. A dedicated CMOS device was designed with arrays of lines 0.35mm in size with 0.8 mm and 10mm periods. Integrated Circuits with or without a passivition layer were tested. To enhance sensitivity, the IC heat source was excited with an AC current. We show that the passivation layer spreads heat so that the lines are not distinguishable. Removing this layer allows us to distinguish the lines in the case of the 10mm period

VvGOLS1 and VvHsfA2 are Involved in the Heat Stress Responses in Grapevine Berries

Among various environmental factors, temperature is a major regulator affecting plant growth, development and fruit composition. Grapevine is the most cultivated fruit plant throughout the world, and grapes are used for wine production and human consumption. The molecular mechanisms involved in grapevine tolerance to high temperature, especially at the fruit level, are poorly understood. To better characterize the sensitivity of berries to the microenvironment, high temperature conditions were locally applied to Vitis vinifera Cabernet Sauvignon clusters. Two genes, VvGOLS1 and VvHsfA2, up-regulated by this treatment, were identified and further characterized. The expression profile of VvGOLS1 correlated positively with galactinol accumulation in heat-stressed berries. However, no galactinol derivatives, such as raffinose and stachyose, accumulated upon heat stress. Heterologous expression of VvGOLS1 in Escherichia coli showed that it encodes a functional galactinol synthase. Transient expression assays showed that the heat stress factor VvHsfA2 transactivates the promoter of VvGOLS1 in a heat stress-dependent manner. Taken together, our results highlight the intrinsic capacity of grape berries to perceive heat stress and to initiate adaptive responses, suggesting that galactinol may play a signaling role in these response

Temperature measurement of sub-micrometric ICs by scanning thermal microscopy

Surface temperature measurements were performed with a Scanning Thermal Microscope mounted with a thermoresistive wire probe of micrometrSurface temperature measurements were performed with a Scanning Thermal Microscope mounted with a thermoresistive wire probe of micrometric size. A CMOS device was designed with arrays of resistive lines 0.35µm in width. The array periods are 0.8 µm and 10µm to study the spatial resolution of the SThM. Integrated Circuits with passivation layers of micrometric and nanometric thicknesses were tested. To enhance signal-to-noise ratio, the resistive lines were heated with an AC current. The passivation layer of nanometric thickness allows us to distinguish the lines when the array period is 10μm. The results raise the difficulties of the SThM measurement due to the design and the topography of ICs on one hand and the size of the thermal probe on the other hand.ic size. A CMOS device was designed with arrays of resistive lines 0.35µm in width. The array periods are 0.8 µm and 10µm to study the spatial resolution of the SThM. Integrated Circuits with passivation layers of micrometric and nanometric thicknesses were tested. To enhance signal-to-noise ratio, the resistive lines were heated with an AC current. The passivation layer of nanometric thickness allows us to distinguish the lines when the array period is 10μm. The results raise the difficulties of the SThM measurement due to the design and the topography of ICs on one hand and the size of the thermal probe on the other hand

A single amino acid change within the R2 domain of the VvMYB5b transcription factor modulates affinity for protein partners and target promoters selectivity

<p>Abstract</p> <p>Background</p> <p>Flavonoid pathway is spatially and temporally controlled during plant development and the transcriptional regulation of the structural genes is mostly orchestrated by a ternary protein complex that involves three classes of transcription factors (R2-R3-MYB, bHLH and WDR). In grapevine (<it>Vitis vinifera </it>L.), several MYB transcription factors have been identified but the interactions with their putative bHLH partners to regulate specific branches of the flavonoid pathway are still poorly understood.</p> <p>Results</p> <p>In this work, we describe the effects of a single amino acid substitution (R69L) located in the R2 domain of VvMYB5b and predicted to affect the formation of a salt bridge within the protein. The activity of the mutated protein (name VvMYB5b^L, the native protein being referred as VvMYB5b^R) was assessed in different <it>in vivo </it>systems: yeast, grape cell suspensions, and tobacco. In the first two systems, VvMYB5b^Lexhibited a modified trans-activation capability. Moreover, using yeast two-hybrid assay, we demonstrated that modification of VvMYB5b transcriptional properties impaired its ability to correctly interact with VvMYC1, a grape bHLH protein. These results were further substantiated by overexpression of <it>VvMYB5b^R</it>and <it>VvMYB5b^L</it>genes in tobacco. Flowers from <it>35S::VvMYB5b^L</it>transgenic plants showed a distinct phenotype in comparison with <it>35S::VvMYB5b^R</it>and the control plants. Finally, significant differences in transcript abundance of flavonoid metabolism genes were observed along with variations in pigments accumulation.</p> <p>Conclusions</p> <p>Taken together, our findings indicate that VvMYB5b^Lis still able to bind DNA but the structural consequences linked to the mutation affect the capacity of the protein to activate the transcription of some flavonoid genes by modifying the interaction with its co-partner(s). In addition, this study underlines the importance of an internal salt bridge for protein conformation and thus for the establishment of protein-protein interactions between MYB and bHLH transcription factors. Mechanisms underlying these interactions are discussed and a model is proposed to explain the transcriptional activity of VvMYB5^Lobserved in the tobacco model.</p

Metabolite analysis reveals distinct spatio-temporal accumulation of anthocyanins in two teinturier variants of cv. ‘Gamay’ grapevines (Vitis vinifera L.)

In most red grape cultivars, anthocyanins accumulate exclusively in the berry skin, while ‘teinturier’ cultivars also accumulate anthocyanins in the pulp. Here, we investigated the teinturier cvs. ‘Gamay de Bouze’ and ‘Gamay Fréaux’ (two somatic variants of the white-fleshed cv. ‘Gamay’) through metabolic and transcript analysis to clarify whether these two somatic variants have the same anthocyanin accumulation pattern in the skin and pulp, and whether primary metabolites are also affected. The skin of the three cultivars and the pulp of ‘Gamay de Bouze’ begun to accumulate anthocyanins at the onset of berry ripening. However, the pulp of ‘Gamay Fréaux’ exhibited a distinct anthocyanin accumulation pattern, starting as early as fruit set with very low level of sugars. The highest level of anthocyanins was found in ‘Gamay Fréaux’ skin, followed by ‘Gamay de Bouze’ and ‘Gamay’. Consistently, the transcript abundance of genes involved in anthocyanin biosynthesis were in line with the anthocyanin levels in the three cultivars. Despite no evident differences in pulp sugar content, the concentration of glucose and fructose in the skin of ‘Gamay Fréaux’ was only half of those in the skin of ‘Gamay’ and ‘Gamay de Bouze’ throughout all berry ripening, suggesting an uncoupled accumulation of sugars and anthocyanins in ‘Gamay Fréaux’. The study provides a comprehensive view of metabolic consequences in grape somatic variants and the three almost isogenic genotypes can serve as ideal reagents to further uncover the mechanisms underlying the linkage between sugar and anthocyanin accumulation.This research was supported partly by the National Key R&D Program of China (2018YFD1000200) and was conducted as part of the LIA INNOGRAPE International Associated Laboratory.Peer reviewe

Local Heat Dissipation and Elasticity of Suspended Silicon Nanowires Revealed by Dual Scanning Electron and Thermal Microscopies

A novel combined setup, with a scanning thermal microscope (SThM) embedded in a scanning electron microscope (SEM), is used to characterize a suspended silicon rough nanowire (NW), which is epitaxially clamped at both sides and therefore monolithically integrated in a microfabricated device. The rough nature of the NW surface, which prohibits vacuum-SThM due to loose contact for heat dissipation, is circumvented by decorating the NW with periodic platinum dots. Reproducible approaches over these dots, enabled by the live feedback image provided by the SEM, yield a strong improvement in thermal contact resistance and a higher accuracy in its estimation. The results-thermal resistance at the tip-sample contact of 188±3.7K µW-1 and thermal conductivity of the NW of 13.7±1.6W m-1 K-1-are obtained by performing a series of approach curves on the dots. Noteworthy, the technique allows measuring elastic properties at the same time-the moment of inertia of the NW is found to be (6.1±1.0) × 10-30m4-which permits to correlate the respective effects of the rough shell on heat dissipation and on the NW stiffness. The work highlights the capabilities of the dual SThM/SEM instrument, in particular the interest of systematic approach curves with well-positioned and monitored tip motion.This investigation has been supported by the Spanish Ministry of Education through the FPU grant , and by the University and Research Secretary of the Business and Knowledge Department of the Generalitat de Catalonia in the project FEM‐IoT (). This research as also been supported by the Spanish National Research Agency (AEi) though the project (AEI/FEDER, EU) . This research has used the Spanish ICTS Network , partially funded by FEDER funds through project . This work has also been supported by the French National Research Agency (ANR) through the projects and the project (LabEx iMUST). The European Commission also supported this investigation through the project (GA 766853) and the project (GA 604668). FPU18/01494 001‐P‐001662 PID2019‐110142RB‐C21 THERMOLOGICS MICRONANOFABS MINATEC‐PLUS‐2 FICTS2019‐02‐40 TIPTOP ANR‐16‐CE09‐0023 ATTSEM ANR‐10‐LABX‐0064 EFINED H2020‐FETOPEN‐2016‐2017 QUANTIHEAT NMP‐2013‐LARGE‐7Peer reviewe