We demonstrate an efficient and continuous microwave photon-to-electron converter with large quantum efficiency (83%) and low dark current. These unique properties are enabled by the use of a high kinetic inductance disordered superconductor, granular aluminium, to enhance light-matter interaction and the coupling of microwave photons to electron tunneling processes. As a consequence of strong coupling, we observe both linear and nonlinear photon-assisted processes where two, three, and four photons are converted into a single electron at unprecedentedly low light intensities.
View Article and Find Full Text PDFRecessive dystrophic epidermolysis bullosa (RDEB) is a rare severe hereditary skin disease characterized by skin and mucosa fragility, resulting in blister formation. The most severe complication in RDEB patients is the development of cutaneous squamous cell carcinoma (SCC), leading to premature death. There is a great deal of evidence suggesting a permissive tumor microenvironment (TME) as a driver of SCC development in RDEB patients.
View Article and Find Full Text PDFWe implemented radio frequency-assisted electrostatic force microscopy (RF-EFM) to investigate the electric field response of biaxially strained molybdenum disulfide (MoS) monolayers (MLs) in the form of mesoscopic bubbles, produced via hydrogen (H)-ion irradiation of the bulk crystal. MoS ML, a semiconducting transition metal dichalcogenide, has recently attracted significant attention due to its promising optoelectronic properties, further tunable by strain. Here, we take advantage of the RF excitation to distinguish the intrinsic quantum capacitance of the strained ML from that due to atomic scale defects, presumably sulfur vacancies or H-passivated sulfur vacancies.
View Article and Find Full Text PDFThe synthesis of heterogeneous Ti(IV)-based catalysts for ethylene polymerization following surface organometallic chemistry concepts is described. The unique feature of this catalyst arises from the silica support, KCC-1. It has (i) a 3D fibrous morphology that is essential to improve the diffusion of the reactants, and (ii) an aluminum-bound hydroxyl group, [(Si-O-Si)(Si-O-)Al-OH] 2, used as an anchoring site.
View Article and Find Full Text PDFNonprecious-metal heterogeneous catalysts with atomically dispersed active sites demonstrated high activity and selectivity in different reactions, and the rational design and large-scale preparation of such catalysts are of great interest but remain a huge challenge. Current approaches usually involve extremely high-temperature and tedious procedures. Here, we demonstrated a straightforward and scalable preparation strategy.
View Article and Find Full Text PDFIn microwave quantum optics, dissipation usually corresponds to quantum jumps, where photons are lost one by one. Here we demonstrate a new approach to dissipation engineering. By coupling a high impedance microwave resonator to a tunnel junction, we use the photoassisted tunneling of quasiparticles as a tunable dissipative process.
View Article and Find Full Text PDFPachyonychia congenita (PC) is a rare keratinizing disorder characterized by painful palmoplantar keratoderma for which there is no standard current treatment. PC is caused by dominant mutations in keratin (K) K6A, K6B, K6C, K16, or K17 genes involved in stress, wound healing, and epidermal barrier formation. Mechanisms leading to pain and painful palmoplantar keratoderma in PC remain elusive.
View Article and Find Full Text PDFCST (Crude Sulfate Turpentine) is an upcycled, biomass raw material derived from pinewood, obtained as a by-product of the Kraft process from the pulp and paper industry. The current article provides an overview of major renewable perfumery ingredients obtained from CST-derived alpha- and beta-pinene to-date and part of the Firmenich manufacturing portfolio, post DRT acquisition.
View Article and Find Full Text PDFThe emerging promise of few-atom metal catalysts has driven the need for developing metal nanoclusters (NCs) with ultrasmall core size. However, the preparation of metal NCs with single-digit metallic atoms and atomic precision is a major challenge for materials chemists, particularly for Ag, where the structure of such NCs remains unknown. In this study, we developed a shape-controlled synthesis strategy based on an isomeric dithiol ligand to yield the smallest crystallized Ag NC to date: [Ag(1,2-BDT)] (1,2-BDT = 1,2-benzenedithiolate).
View Article and Find Full Text PDFAlkylation of Ti(CH)Cl1 by MeLi gives the homoleptic Ti(CH)2 for the first time in the absence of any coordinating solvent. The reaction of 2 with silica pretreated at 700 °C (SiO) gives two inequivalent silica-supported Ti-methyl species 3. Complex 3 was characterized by IR, microanalysis (ICP-OES, CHNS, and gas quantification), and advanced solid-state NMR spectroscopy (H, C, DQ, TQ, and HETCOR).
View Article and Find Full Text PDFWe report here the first step by step anchoring of a W(≡CBu)(CHBu) complex on a highly crystalline and mesoporous MOF, namely Zr-NU-1000, using a Surface Organometallic Chemistry (SOMC) concept and methodology. SOMC allowed us to selectively graft the complex on the Zr clusters and characterize the obtained single site material using state of the art experimental methods including extensive solid-state NMR techniques and HAADF-STEM imaging. Further FT-IR spectroscopy revealed the presence of a W═O moiety arising from the in situ reaction of the W≡CBu functionality with the coordinated water coming from the 8-connected hexanuclear Zr clusters.
View Article and Find Full Text PDFNeurotropic flavivirus Japanese encephalitis virus (JEV) and West Nile virus (WNV) are amongst the leading causes of encephalitis. Using label-free quantitative proteomics, we identified proteins differentially expressed upon JEV (gp-3, RP9) or WNV (IS98) infection of human neuroblastoma cells. Data are available via ProteomeXchange with identifier PXD016805.
View Article and Find Full Text PDFThe effects of native defects and exposed facets on the thermodynamic stability and photocatalytic characteristics of Ta3N5 for water splitting are studied by applying accurate quantum computations on the basis of density functional theory (DFT) with the range-separated hybrid functional (HSE06). Among the three explored potential candidates for O-enriched bulk Ta3N5 structures with substituted O at N sites and accompanied by interstitial O or Ta-vacancies, the first and third structures are relevant. The four possible (001), (010), (100) and (110) low Miller index exposed facets of Ta(3-x)N(5-y)Oy (y = 7x) are also explored, which show lower formation energies than those of Ta3N5.
View Article and Find Full Text PDFWest Nile virus (WNV), a member of the genus and currently one of the most common arboviruses worldwide, is associated with severe neurological disease in humans. Its high potential to reemerge and rapidly disseminate makes it a bona fide global public health problem. The surface membrane glycoprotein (M) has been associated with -induced pathogenesis.
View Article and Find Full Text PDFWe present a novel approach to produce gold nanoclusters (Au NCs) in the pores of mesoporous silica nanoparticles (MSNs) by sequential and controlled addition of metal ions and reducing agents. This impregnation technique was followed to confine Au NCs inside the pores of MSNs without adding external ligands or stabilizing agents. TEM images show a uniform distribution of monodisperse NCs with an average size of 1.
View Article and Find Full Text PDFThe metal complex (Zr(CH3)4(THF)2) has been fully synthesized, characterized and grafted onto partially dehydroxylated silica to give two surface species [([triple bond, length as m-dash]Si-O-)Zr(CH3)3(THF)2] (minor) and [([triple bond, length as m-dash]Si-O-)2Zr(CH3)2(THF)2] (major) which have been characterized by SS NMR, IR, and elemental analysis. These supported pre-catalysts exhibit the best conversion of CO2 to cyclic carbonates, as compared to the previously reported SOMC catalysts.
View Article and Find Full Text PDFChem Commun (Camb)
December 2019
We report carbon nanotube-encapsulated cobalt as an efficient oxygen reduction electrocatalyst (onset potential of 0.94 V and half-potential of 0.84 V).
View Article and Find Full Text PDFWith this protocol, a well-defined singlesite silica-supported heterogeneous catalyst [(≡Si-O-)Hf(=NMe)(η-NMe2)] is designed and prepared according to the methodology developed by surface organometallic chemistry (SOMC). In this framework, catalytic cycles can be determined by isolating crucial intermediates. All air-sensitive materials are handled under inert atmosphere (using gloveboxes or a Schlenk line) or high vacuum lines (HVLs, <10 mbar).
View Article and Find Full Text PDFA platinum complex, (CH)Pt(COD), is grafted via surface organometallic chemistry (SOMC) on morphology-controlled anatase TiO to generate single, isolated Pt atoms on TiO nano-platelets. The resulting material is characterized by FT-IR, high resolution scanning transmission electron microscopy (HRSTEM), NMR, and XAS, and then used to perform photocatalytic water splitting. The photocatalyst with SOMC-grafted Pt shows superior performance in photocatalytic hydrogen evolution and strongly suppresses the backwards reaction of H and O forming HO under dark conditions, compared to the photocatalyst prepared by impregnation at the same Pt loading.
View Article and Find Full Text PDFSingle atom catalysis (SAC) is a recent discipline of heterogeneous catalysis for which a single atom on a surface is able to carry out various catalytic reactions. A kind of revolution in heterogeneous catalysis by metals for which it was assumed that specific sites or defects of a nanoparticle were necessary to activate substrates in catalytic reactions. In another extreme of the spectrum, surface organometallic chemistry (SOMC), and, by extension, surface organometallic catalysis (SOMCat), have demonstrated that single atoms on a surface, but this time with specific ligands, could lead to a more predictive approach in heterogeneous catalysis.
View Article and Find Full Text PDFArboviruses like chikungunya and Ross River (RRV) are responsible for massive outbreaks of viral polyarthritis. There is no effective treatment or vaccine available against these viruses that induce prolonged and disabling arthritis. To explore the physiopathological mechanisms of alphaviral arthritis, we engineered a recombinant RRV expressing a NanoLuc reporter (RRV-NLuc), which exhibited high stability, near native replication kinetics and allowed real time monitoring of viral spread in an albino mouse strain.
View Article and Find Full Text PDFProc Natl Acad Sci U S A
May 2019
Close proximity between different catalytic sites is crucial for accelerating or even enabling many important catalytic reactions. Photooxidation and photoreduction in photocatalysis are generally separated from each other, which arises from the hole-electron separation on photocatalyst surface. Here, we show with widely studied photocatalyst Pt/[Formula: see text] as a model, that concentrating abundant oxygen vacancies only at the metal-oxide interface can locate hole-driven oxidation sites in proximity to electron-driven reduction sites for triggering unusual reactions.
View Article and Find Full Text PDFThe direct conversion of propane into aromatics (BTX) using modified ZSM-5 was achieved with a strategy of "catalysis by design". In contrast to the classical mode of action of classical aromatization catalysts which are purely based on acidity, we have designed the catalyst associating two functions: One function (Ti-hydride) was selected to activate the C-H bond of propane by σ-bond metathesis to further obtain olefin by β-H elimination and the other function (Brønsted acid) being responsible for the oligomerization, cyclization, and aromatization. This bifunctional catalyst was obtained by selectively grafting a bulky organometallic complex of tetrakis(neopentyl)titanium (TiNp4) at the external surface (external silanol ([triple bond, length as m-dash]Si-OH) group) of [H-ZSM-5300] to obtain [Ti/ZSM-5] catalyst 1.
View Article and Find Full Text PDFDemonstrating the topological protection of Andreev states in Josephson junctions is an experimental challenge. In particular the telltale 4π periodicity expected for the current phase relation has remained elusive, because of fast parity breaking processes. It was predicted that low temperature ac susceptibility measurements could reveal the topological protection of quantum spin Hall edge states by probing their low energy Andreev spectrum at finite frequency.
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