Endothelial cells (ECs) play an important role in tissue homeostasis. Recently, EC lipid metabolism has emerged as a regulator of EC function. The liver X receptors (LXRs) are involved in the transcriptional regulation of genes involved in lipid metabolism and have been identified as a potential target in cardiovascular disease. We aimed to decipher the role of LXRs in the regulation of lipid metabolism in human aortic endothelial cells.
We here emphasize that the surface enhanced Raman scattering (SERS) intensity has to be optimized by choosing the appropriate gold nanoparticles size for two excitation wavelengths; 632.8 and 785 nm. We discuss the role of the position and of the order of the localized surface plasmon resonance (LSPR) in such optimization for both wavelengths. At 632.8 nm, the best SERS intensity is reached for a LSPR located between the excitation and Raman wavelengths whereas at 785 nm, the LSPR should be placed outside this range. The third order of LSPR is shown to have no influence on the SERS intensity.
We focus on improving the surface-enhanced Raman scattering (SERS) of dimer nanoantenna by tailoring the shape of the coupled nanoantennas extremities from rounded to straight or slanted ones. A numerical model based on the discrete dipole approximation method—taking into account periodicity, adhesion layer, and roughness—is first validated by comparison with localized surface plasmon resonance (LSPR) and SERS experiments on round-edged dimer nanoantennas and then used to investigate the effect of the straight or slanted gap in the dimer antenna. Simulations show that both LSPR and SERS can be tuned by changing the gap slanting angle. The SERS enhancement factor can also be improved by 2 orders of magnitude compared to the one reached using a rounded gap. Therefore, the slanting angle can be used as a new control parameter in the design of SERS substrates to guarantee stronger field confinement and higher sensitivity, especially as its feasibility is demonstrated.
We here emphasize that the Surface Enhanced Raman Scattering (SERS) intensity has to be optimized by choosing the appropriate gold nanoparticles size for two excitation wavelengths: 632.8 and 785 nm. We discuss the role of the position and of the order of the Localized Surface Plasmon Resonance (LSPR) in such optimization for both wavelengths. At 632.8 nm, the best SERS intensity is reached for a LSPR located between the excitation and Raman wavelengths whereas at 785 nm, the LSPR should be placed outside this range. The third order of LSPR is shown to have no influence on the SERS intensity.
Rates of type 2 diabetes (T2D) are rapidly increasing worldwide, including in regions, and among populations, of the globe where sickle cell trait (SCT) is prevalent. SCT, the heterozygote form of sickle cell disease, is generally considered a benign condition. However, evidence shows that vascular function is more severely impaired in people with combined T2D and SCT (T2D-SCT) than in those with T2D only. Furthermore, evidence suggests that SCT could complicate screening for T2D, thereby increasing the risk of delayed diagnosis of T2D. In light of this information, the main objectives of this thesis were to study the challenges related to diagnosing and monitoring T2D in individuals with SCT, and to evaluate the mechanisms and consequences of the amplified vascular dysfunction observed in T2D-SCT. Study 1 compared the agreement between two standard measures of glycemia, HbA1c and fasting glucose, and one alternative measure of glycemia, fructosamine, in Senegalese adults with and without SCT. The findings revealed substantial disparities between the markers of glycemia, and these differences were exaggerated in individuals with SCT. Study 2 illustrated that SCT could potentially augment the risk of developing retinopathy, nephropathy, and hypertension in T2D, and demonstrated that AGEs are likely implicated in the vascular dysfunction observed in T2D-SCT. Studies 3 and 4 studied microvascular function in a mouse model of T2D-SCT. Study 3 showed that T2D-SCT mice had significantly impaired endothelium-dependent vasodilation in-vivo. Study 4 revealed that ACH-mediated vasodilation in-vivo was significantly elevated in the microvasculature of mice with combined T2D and SCT due to cyclooxygenase-2 dependent mechanisms. Overall these findings deepen our understanding about the complexities related to diagnosing and managing T2D in individuals with SCT
Abstract The use of the antenna principle is well known and widely used in the radio or microwave frequency range. This principle can also be extended to the optical domain, and it finds some applications in various optical fields. However, the use of the “antenna effect” in the optical range (from near‐ultraviolet to near‐infrared) is still unexplored. This is explained by the fact that the transition from the radio to the optical frequencies is a technological challenge because the antenna size has to be in the same order of magnitudes as the transmitted/collected frequencies (nanometric scale). Moreover, the resonance conditions of these antennas at the optical frequencies change compared with the resonance conditions known for weaker frequencies. What we describe in this article belongs to a more general concept in physics: the interaction between electromagnetic waves and matter. We propose to start with the description of electromagnetic waves propagation in vacuum given by the expression of Maxwell's equations. We will then describe the interaction between these waves with matter at the microscopic scale just before extending the explanation to the macroscopic scale. This approach is chosen to introduce all parameters linked to the matter “response” when excited by these waves. Then, this will allow us to extract the particular case of metallic materials constituting the antenna that we will study in the article. At the end, we will focus on the concept of a nanoantenna and thus on the light matter interaction at the nanoscale.
