Translational models for vascular cognitive impairment: a review including larger species.

BACKGROUND: Disease models are useful for prospective studies of pathology, identification of molecular and cellular mechanisms, pre-clinical testing of interventions, and validation of clinical biomarkers. Here, we review animal models relevant to vascular cognitive impairment (VCI). A synopsis of each model was initially presented by expert practitioners. Synopses were refined by the authors, and subsequently by the scientific committee of a recent conference (International Conference on Vascular Dementia 2015). Only peer-reviewed sources were cited. METHODS: We included models that mimic VCI-related brain lesions (white matter hypoperfusion injury, focal ischaemia, cerebral amyloid angiopathy) or reproduce VCI risk factors (old age, hypertension, hyperhomocysteinemia, high-salt/high-fat diet) or reproduce genetic causes of VCI (CADASIL-causing Notch3 mutations). CONCLUSIONS: We concluded that (1) translational models may reflect a VCI-relevant pathological process, while not fully replicating a human disease spectrum; (2) rodent models of VCI are limited by paucity of white matter; and (3) further translational models, and improved cognitive testing instruments, are required

Nanoscale effect on the formation of the amorphous Ni silicide by rapid thermal annealing from crystalline and pre-amorphized silicon

International audienceThe Ni monosilicide alloyed with Pt is widely used as contact material in advanced microelectronics devices and a good knowledge of silicide formation kinetics is required for the process control. In this work, the nature, and the growth kinetics of the first silicide obtained during the solid-state reaction between the Ni0.9Pt0.1 and the Si are studied for different pre amorphization implant (PAI) conditions as well as for a reference sample without PAI. Reactions between a 10 nm thick Ni0.9Pt0.1 film and Si (100) substrate are analyzed after several rapid thermal anneals (RTA). The nature of the first silicide is determined by Fourier Transform of TEM images and by chemical TEM-EDX analyses. The silicide growth behavior is determined by measuring the silicide thickness by X ray reflectivity (XRR) after the partial reaction induced by RTAs at different temperatures and times. To determine the growth law, the linear parabolic model is first considered but a nonlinear reactive diffusion model must be developed to accurately reproduce the experimental results. From this model, the effective diffusion coefficient as well as its activation energy were determined for the three samples with PAI and the reference sample without PAI. The influence of the driving force on the nonlinear diffusion for thin films is proved, and the impact of the amorphous substrate on the kinetics parameters is quantified and compared to the literature

On the influence of Ni(Pt)Si thin film formation on agglomeration threshold temperature and its impact on 3D imaging technology integration

Ni(10 at.% Pt) monosilicide is used as contact in microelectronics but suffers from degradation at relatively low temperatures due to agglomeration. Recent results obtained on 28 nm-FDSOI microelectronics devices have demonstrated severe yield loss after an anneal at 550 °C/2 h linked to Ni(Pt)Si film dewetting. Such agglomeration thermal budget is 100 °C lower than the ones measured on blanket wafers with in-situ or exsitu four-point probe measurements. In this context, the aim of this paper is to investigate the effect Ni(Pt)Si formation process on the Ni(Pt)Si agglomeration using different approaches as (i) the classical one in which one anneal is applied to form silicide and leads also to agglomeration, (ii) the silicide formation through the standard SALICIDE process, "Self-Aligned Silicide", and a subsequent anneal to induce agglomeration, and (iii) the standard SALICIDE process for silicide formation followed by an encapsulation of the top silicide surface by a SiN layer as applied in devices, and submitted finally to the agglomeration anneal. Our work demonstrated that the film thermal stability is influenced by the sequencing of the selective etch (SE) in the formation process and whether it is formed by a single or a double anneal. Another conclusion of this work is that four-point probe measurements are not sensitive enough to well estimate the real starting point of agglomeration phenomenon which is detrimental for devices (holes formation at the triple junctions). Some additional characterizations such as tilted Scanning Electron Microscopy (tilted SEM) are deeply needed for an accurate determination of agglomeration thermal budget. This study allows clarifying the main parameters leading to agglomeration: the film thickness and the grain size appear to be the more important ones

Observation of HfO2 thin films by deep UV spectroscopic ellipsometry

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Platinum redistribution in the Ni0.9Pt0.1/InP system: Impact on solid-state reaction and layer morphology

International audienceIn the scope of integrating III-V device contacts on a 300 mm platform, Ni-based contacts are envisioned. In this regard, the diffusion and solubility of Pt in the Ni 0.9 Pt 0.1 /InP system, in addition to the impact of the Pt-alloying of Ni thin films on InP over the solid-state reaction and layer morphology, have been investigated. Results have shown that at low temperature (T&lt;300 ℃), the presence of Pt (i) partially hinders the diffusion of Ni towards the InP substrate, and as a result (ii) delays the growth of the Ni-In-P amorphous layer, in addition to (iii) postponing the consumption of the Ni 0.9 Pt 0.1 layer. At higher temperatures (T≥300 ℃), the thermal energy brought to the system overcomes the Pt-induced partially hindered Ni diffusion, and the observed phase formation sequence is not affected by the presence of Pt. The low solubility of Pt does not allow its incorporation in the formed Ni-based phases (Ni 2 P, Ni 2 P and Ni 2 InP). Instead, the latter is rejected from the forming interface, which allows it to participate to the formation of the stable Pt 3 In 7 crystallized phase.</div

Endothelial GqPCR activity controls capillary electrical signaling and brain blood flow through PIP₂ depletion

Significance Capillaries, the smallest blood vessels, mediate the on-demand delivery of oxygen and nutrients required to support the function of active cells throughout the brain. But how blood flow is directed to cells in active brain regions to satisfy their energy needs is poorly understood. We demonstrate that the plasma membrane phospholipid, PIP 2 , is fundamental to sustaining the activity of inwardly rectifying potassium channels—the molecular feature that allows capillary endothelial cells to sense ongoing neuronal activity and trigger an increase in local blood flow. We further show that chemical factors released in the brain, including those associated with neuronal activity, cause changes in the levels of PIP 2 , thereby altering endothelial potassium channel signaling and controlling cerebral blood flow. </jats:p

Nickel-based CMOS-compatible contacts on p-In 0.53 Ga 0.47 As for III-V / silicon hybrid lasers

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Integration, BEOL, and Thermal Stress Impact on CMOS-Compatible Titanium-Based Contacts for III–V Devices on a 300-mm Platform

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Chemical interface analysis of as grown HfO2 ultrathin films on SiO2

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Chemical interface analysis of as grown HfO2 ultrathin films on SiO2

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