Modulation of Hepatocarcinoma Cell Morphology and Activity by Parylene-C Coating on PDMS

BACKGROUND: The ability to understand and locally control the morphogenesis of mammalian cells is a fundamental objective of cell and developmental biology as well as tissue engineering research. We present parylene-C (ParC) deposited on polydimethylsiloxane (PDMS) as a new substratum for in vitro advanced cell culture in the case of Human Hepatocarcinoma (HepG2) cells. PRINCIPAL FINDINGS: Our findings establish that the intrinsic properties of ParC-coated PDMS (ParC/PDMS) influence and modulate initial extracellular matrix (ECM; here, type-I collagen) surface architecture, as compared to non-coated PDMS substratum. Morphological changes induced by the presence of ParC on PDMS were shown to directly affect liver cell metabolic activity and the expression of transmembrane receptors implicated in cell adhesion and cell-cell interaction. These changes were characterized by atomic force microscopy (AFM), which elucidated differences in HepG2 cell adhesion, spreading, and reorganization into two- or three-dimensional structures by neosynthesis of ECM components. Local modulation of cell aggregation was successfully performed using ParC/PDMS micropatterns constructed by simple microfabrication. CONCLUSION/SIGNIFICANCE: We demonstrated for the first time the modulation of HepG2 cells' behavior in relation to the intrinsic physical properties of PDMS and ParC, enabling the local modulation of cell spreading in a 2D or 3D manner by simple microfabrication techniques. This work will provide promising insights into the development of cell-based platforms that have many applications in the field of in vitro liver tissue engineering, pharmacology and therapeutics

Lasing oscillation in a three-dimensional photonic crystal nanocavity with a complete bandgap

We demonstrate lasing oscillation in a three-dimensional photonic crystal nanocavity. The laser is realized by coupling a cavity mode, which is localized in a complete photonic bandgap and exhibits the highest quality factor of ~38,500, with high-quality semiconductor quantum dots. We show a systematic change in the laser characteristics, including the threshold and the spontaneous emission coupling factor by controlling the crystal size, which consequently changes the strength of photon confinement in the third dimension. This opens up many interesting possibilities for realizing future ultimate light sources and three-dimensional integrated photonic circuits and for more fundamental studies of physics in the field of cavity quantum electrodynamics.Comment: 14 pages, 4 figure

Coupling of quantum dot light emission with point defect cavity resonances in three-dimensional photonic crystals

Regardless of the excellent feature of three-dimensional (3D) photonic crystals (PhCs) to manipulate lights in all direction irrespective of their polarization directions, two-dimensional (2D) PhCs have been preferred by researchers in this field than 3D PhCs, because 2D PhCs provide us manipulatability of light, which is nearly comparable to those of 3D PhCs, without apparent difficulty in fabrication. However, the present condition, where the killer application of PhCs is absent after 20 years intensive research, makes us to reconsider whether the polarization-limited condition for use and fragile structures of 2D PhCs are really a drawback for practical application or not. The sole reason why 3D PhCs have been avoided is their intrinsic complexity of the structure. Once a technology, which enables stable assembly of 3D fine structures with high precision, the balance of favor between 2D and 3D PhCs would change. In this talk, we introduce the first demonstration of coupling of light emission from quantum dots (QDs) with a nanocavity in a 3D PhC operating at optical communication wavelengths. The combination of QDs and a nanocavity in a 3D PhC provides a fully-confined system both for electrons and photons simultaneously. Such a system operating at optical communication wavelengths could move the realization of quantum cryptography communication and quantum computer a step closer. Our demonstrations increase their importance with the fact that they were done using III-V semiconductor materials at room temperature. The fabrication technology established here should greatly enhance exploration of not only 3D PhCs but also PhCs and fine-structure devices in general. Details of our work will be presented at the talk

COVID-19 symptoms at hospital admission vary with age and sex: results from the ISARIC prospective multinational observational study

Background: The ISARIC prospective multinational observational study is the largest cohort of hospitalized patients with COVID-19. We present relationships of age, sex, and nationality to presenting symptoms. Methods: International, prospective observational study of 60 109 hospitalized symptomatic patients with laboratory-confirmed COVID-19 recruited from 43 countries between 30 January and 3 August 2020. Logistic regression was performed to evaluate relationships of age and sex to published COVID-19 case definitions and the most commonly reported symptoms. Results: ‘Typical’ symptoms of fever (69%), cough (68%) and shortness of breath (66%) were the most commonly reported. 92% of patients experienced at least one of these. Prevalence of typical symptoms was greatest in 30- to 60-year-olds (respectively 80, 79, 69%; at least one 95%). They were reported less frequently in children (≤ 18 years: 69, 48, 23; 85%), older adults (≥ 70 years: 61, 62, 65; 90%), and women (66, 66, 64; 90%; vs. men 71, 70, 67; 93%, each P < 0.001). The most common atypical presentations under 60 years of age were nausea and vomiting and abdominal pain, and over 60 years was confusion. Regression models showed significant differences in symptoms with sex, age and country. Interpretation: This international collaboration has allowed us to report reliable symptom data from the largest cohort of patients admitted to hospital with COVID-19. Adults over 60 and children admitted to hospital with COVID-19 are less likely to present with typical symptoms. Nausea and vomiting are common atypical presentations under 30 years. Confusion is a frequent atypical presentation of COVID-19 in adults over 60 years. Women are less likely to experience typical symptoms than men

Elaboration de cellules photovoltaïques à base de diséléniure de cuivre et d'indium électrodéposé

PARIS-BIUSJ-Thèses (751052125) / SudocPARIS-BIUSJ-Physique recherche (751052113) / SudocSudocFranceF

in situ laser monitoring of laser treatment of thin film stacks

International audienc

Ordered Submicron Structures in Optical Coatings Obtained by Laser Dewetting of Metallic Thin Film Stacks

International audienceObtaining large surfaces covered by submicron structures is a challenge in patterning coatings. Using laser induced dewetting, large surface self-assembled ordered metallic structures were used to modify optical properties of interference coatings

A Quantitative Investigation of Functionalized Glazing Stacks by Atom Probe Tomography

International audienc