Novel high-pressure/high-temperature reactor cell for in situ and operando x-ray absorption spectroscopy studies of heterogeneous catalysts at synchrotron facilities.

This paper presents the development of a novel high-pressure/high-temperature reactor cell dedicated to the characterization of catalysts using synchrotron x-ray absorption spectroscopy under operando conditions. The design of the vitreous carbon reactor allows its use as a plug-flow reactor, monitoring catalyst samples in a powder form with a continuous gas flow at high-temperature (up to 1000 °C) and under high pressure (up to 1000 bar) conditions, depending on the gas environment. The high-pressure/high-temperature reactor cell incorporates an automated gas distribution system and offers the capability to operate in both transmission and fluorescence detection modes.

Valuation of Costs in Health Economics During Financial and Economic Crises: A Case Study from Lebanon.

In 2019, we embarked on a study on the economic burden of multiple sclerosis (MS) in Lebanon, in collaboration with a premier Lebanese MS center. This coincided with a triple disaster in Lebanon, comprising the drastic economic and financial crisis, the COVID-19 pandemic, and the consequences of the explosion of Beirut's port. Specifically, the economic and financial turmoil made the valuation of costs challenging.

Cu segregation in Au-Cu nanoparticles exposed to hydrogen atmospheric pressure: how is fcc symmetry maintained?

In a recent work [A. Nassereddine 2021, , 2104571] we reported the atomic-scale structure and dynamics of sub-4 nm sized Au nanoparticles (NPs) supported on titania in H at atmospheric pressure obtained by using aberration-corrected environmental transmission electron microscopy (ETEM), density functional theory (DFT) optimizations and molecular dynamic (AIMD) simulations. Our results showed unstable Au NPs losing their face-centred cubic (fcc) symmetry (from fcc to non-fcc symmetries) and revealed the drastic effect of hydrogen adsorption.

Revealing Size Dependent Structural Transitions in Supported Gold Nanoparticles in Hydrogen at Atmospheric Pressure.

The enhancement of the catalytic activity of gold nanoparticles with their decreasing size is often attributed to the increasing proportion of low-coordinated surface sites. This correlation is based on the paradigmatic picture of working gold nanoparticles as perfect crystal forms having complete and static outer surface layers whatever their size. This picture is incomplete as catalysts can dynamically change their structure according to the reaction conditions and as such changes can be eventually size-dependent.

Ligand Nanocluster Array Enables Artificial-Intelligence-Based Detection of Hidden Features in T-Cell Architecture.

Protein patterning has emerged as a powerful means to interrogate adhering cells. However, the tools to apply a sub-micrometer periodic stimulus and the analysis of the response are still being standardized. We propose a technique combining electron beam lithography and surface functionalization to fabricate nanopatterns compatible with advanced imaging.

Supported Molybdenum Carbide and Nitride Catalysts for Carbon Dioxide Hydrogenation.

Catalysts based on molybdenum carbide or nitride nanoparticles (2-5 nm) supported on titania were prepared by wet impregnation followed by a thermal treatment under alkane (methane or ethane)/hydrogen or nitrogen/hydrogen mixture, respectively. The samples were characterized by elemental analysis, volumetric adsorption of nitrogen, X-ray diffraction, and aberration-corrected transmission electron microscopy. They were evaluated for the hydrogenation of CO in the 2-3 MPa and 200-300°C ranges using a gas-phase flow fixed bed reactor.

Biphasic mechanosensitivity of T cell receptor-mediated spreading of lymphocytes.

Mechanosensing by T cells through the T cell receptor (TCR) is at the heart of immune recognition. While the mechanobiology of the TCR at the molecular level is increasingly well documented, its link to cell-scale response is poorly understood. Here we explore T cell spreading response as a function of substrate rigidity and show that remarkably, depending on the surface receptors stimulated, the cellular response may be either biphasic or monotonous.

Improved long-term protection against Mycobacterium tuberculosis Beijing/W in mice after intra-dermal inoculation of recombinant BCG expressing latency associated antigens.

Bacille Calmette-Guérin (BCG) is the vaccine against tuberculosis (TB), but has varied efficacy in different geographical locations. Recombinant strategies to genetically modify the organism to enhance the quality of the immune response have aimed at improving BCG efficacy. Here we describe such a strategy using rBCGΔureC∷hly expressing defined latency-associated antigens and test this construct for long-term protection against an isolate of the Mycobacterium tuberculosis (Mtb) Beijing/W lineage.