Rapid antigen tests (RATs) are widely used worldwide to detect SARS-CoV-2 since they are an easy-... more Rapid antigen tests (RATs) are widely used worldwide to detect SARS-CoV-2 since they are an easy-to-use kit and offer rapid results. The RAT detects the presence of the nucleocapsid protein, which is located inside the virus. However, the sensitivity of the different RATs varies between commercially available kits. The test result might change due to various factors, such as the variant type, infection date, swab’s surface, the manner in which one performs the testing and the mucus components. Here, we compare the detection limit of seven commercially available RATs by introducing them to known SARS-CoV-2 nucleocapsid protein amounts from the Omicron variant. It allows us to determine the detection limit, disregarding the influences of other factors. A lower detection limit of the RAT is necessary since earlier detection will help reduce the spread of the virus and allow faster treatment, which might be crucial for the population at risk.
An entry from the Cambridge Structural Database, the world's repository for small molecule cr... more An entry from the Cambridge Structural Database, the world's repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.
L'invention porte sur un procede de formation d'une surface nanostructuree, le procede co... more L'invention porte sur un procede de formation d'une surface nanostructuree, le procede comprenant la fourniture d'une surface nanostructuree initiale ayant un reseau de structures a rapport d'aspect eleve forme sur un substrat plan ; la formation d'un moule a empreinte negative de la surface nanostructuree initiale, le moule a empreinte negative comprenant un materiau flexible ; la deformation du moule a empreinte negative ; et l'utilisation du moule a empreinte negative deformee pour former une replique deformee de la surface nanostructuree initiale, l'etape de deformation etant effectuee au moins avant, durant ou apres l'introduction d'un materiau pour former la replique deformee dans le moule a empreinte negative.
Size effects were investigated in thin amorphous TiO2ALD films. Significant changes in film densi... more Size effects were investigated in thin amorphous TiO2ALD films. Significant changes in film density and Ti+3/Ti+4species ratio were discovered; this was attributed to surface reconstruction and formation of oxygen vacancies during the ALD process.
Proceedings of the National Academy of Sciences, 2021
Significance Dislocation edges on metal surfaces provide loosely bonded atoms, which make the sur... more Significance Dislocation edges on metal surfaces provide loosely bonded atoms, which make the surface more active for chemical corrosion and enhance the chemical reactivity. In this work, we introduce and demonstrate an autocatalytic method in which the dislocation lines in alloys can serve as a template for the growth of a different inorganic material as nanowires. We explain the formation mechanism of an incorporated system of single crystal gold(I)-cyanide nanowires on nanoporous gold during selective dealloying, using the dislocation ends in the prestrained Au-Ag alloy as catalytic centers for crystallization. This method may provide a possible route for controlling the growth direction, shape, and morphology of a crystal according to the original alloy’s slip system.
Jania sp. is an articulated coralline red alga that is abundant in the shallow waters of oceans w... more Jania sp. is an articulated coralline red alga that is abundant in the shallow waters of oceans worldwide. We have previously demonstrated that its structure is highly intricate and exhibits hierarchical organization across multiple length scales from the macro to the nano scale. Moreover, we have proven that the inner pores of its structure are helical, conveying the alga greater compliance as compared to a cylindrical configuration. Herein, we reveal new insights on the structure of Jania sp., particularly on its crystallographic variations and the internal elemental distribution of Mg and Ca. We show that the high-Mg calcite cell wall nanocrystals of Jania sp. are arranged in layers with alternating Mg contents. Moreover, we show that this non-homogenous elemental distribution assists the alga in preventing fracture caused by crack propagation. We further discover that each one of the cell wall nanocrystals in Jania sp. is not a single crystal as was previously thought, but rather comprises Mg-rich calcite nanoparticles demonstrating various crystallographic orientations, arranged periodically within the layered structure. We also show that these Mg-rich nanoparticles are present in yet another species of the coralline red algae, Corallina sp., pointing to the generality of this phenomenon. To the best of our knowledge this is a first report on the existence of Mg-rich nanoparticles in the coralline red algae mineralized tissue. We envisage that our findings on the bio-strategy found in the alga to enhance the fracture toughness will have an impact on the design of structures with superior mechanical properties. Statement of Significance: Understanding the structure-property relation in biomineralized tissues is of great importance in unveiling Nature's material design strategies, which form the basis for the development of novel structural materials. Crystallographic and elemental variations in the skeletal parts of the coralline red algae and their cumulative contribution to prevention of mechanical failure are yet poorly studied. Herein, we reveal that the high-Mg calcite cell wall nanocrystals of Jania sp. are arranged in layers with alternating Mg concentrations and reveal that this organization facilitates crack deflection, thereby preventing catastrophic fracture. We further discovered that the nanocrystals contain incoherent Mg-rich nanoparticles and suggest that they form via spinodal decomposition of the Mg-ACC precursor and self-arrange periodically throughout the alga's mineralized cell wall, a phenomenon most likely to be widespread in high-Mg calcite biomineralization.
Soft corals (Cnidaria, Anthozoa, Octocorallia, Alcyonacea) produce internal sclerites of calcium ... more Soft corals (Cnidaria, Anthozoa, Octocorallia, Alcyonacea) produce internal sclerites of calcium carbonate previously shown to be composed of calcite, the most stable calcium carbonate polymorph. Here we apply multiple imaging and physical chemistry analyses to extracted and in-vivo sclerites of the abundant Red Sea soft coral, Ovabunda macrospiculata, to detail their mineralogy. We show that this species' sclerites are comprised predominantly of the less stable calcium carbonate polymorph vaterite (>95%), with much smaller components of aragonite and calcite. Use of this mineral, which is typically considered to be metastable, by these soft corals has implications for how it is formed as well as how it will persist during the anticipated anthropogenic climate change in the coming decades. This first documentation of vaterite dominating the mineral composition of O. macrospiculata sclerites is likely just the beginning of establishing its presence in other soft corals. STATEMENT OF SIGNIFICANCE: Vaterite is typically considered to be a metastable polymorph of calcium carbonate. While calcium carbonate structures formed within the tissues of octocorals (phylum Cnidaria), have previously been reported to be composed of the more stable polymorphs aragonite and calcite, we observed that vaterite dominates the mineralogy of sclerites of Ovabunda macrospiculata from the Red Sea. Based on electron microscopy, Raman spectroscopy, and X-ray diffraction analysis, vaterite appears to be the dominant polymorph in sclerites both in the tissue and after extraction and preservation. Although this is the first documentation of vaterite in soft coral sclerites, it likely will be found in sclerites of other related taxa as well.
Semiconductors have numerous applications in both science and technology. Several methods have be... more Semiconductors have numerous applications in both science and technology. Several methods have been developed to engineer their band gap, which is one of the most important parameters of semiconductors. Here, it is shown that the incorporation of various amino acids into the crystal lattice of copper (I) oxide, akin to the way living organisms incorporate organic macromolecules into minerals during biomineralization, leads to significant shrinkage in the volume of the host unit cell and a strong blueshift in the band gap of up to ≈18%. In examining the potential location of the bio‐organic molecules within the inorganic host's lattice, a very good fit between the proposed model of incorporation and experimental findings is found. The bioinspired phenomenon of band gap widening is thought to be attributable to the void‐induced quantum confinement effect, even though observed in micrometer‐sized crystals. This hypothesis is supported by developing a tight‐binding model that is fou...
Surface reconstruction is shown to exist in nanometric amorphous films of Al2O3, causing differen... more Surface reconstruction is shown to exist in nanometric amorphous films of Al2O3, causing different short-range order at the surface.
Energy-variable synchrotron x-ray diffraction was applied to probe local structure in different k... more Energy-variable synchrotron x-ray diffraction was applied to probe local structure in different kinds of aragonitic seashells with spatial resolution. All investigated specimens revealed lattice distortions of biogenic aragonite with respect to the geological mineral. The obtained data are analyzed in terms of residual strains induced by intercalating organic macromolecules.
We compare the electrical properties of HfO2/Al2O3 nano-laminates with those of the ternary HfxAl... more We compare the electrical properties of HfO2/Al2O3 nano-laminates with those of the ternary HfxAlyO compound in metal oxide semiconductor (MOS) capacitors. The dielectrics were deposited by atomic layer deposition on InGaAs. Water, ozone, and oxygen plasma were tested as oxygen precursors, and best results were obtained using water. The total dielectric thickness was kept constant in our experiments. It was found that the effective dielectric constant increased and the leakage current decreased with the number of periods. Best results were obtained for the ternary compound. The effect of the sublayer thicknesses on the electrical properties of the interface was carefully investigated, as well as the role of post-metallization annealing. Possible explanations for the observed trends are provided. We conclude that the ternary HfxAlyO compound is more favorable than the nano-laminates approach for InGaAs based MOS transistor applications.
Thermal activated atomic layer deposited (t) (ALD) and plasma enhanced (p) ALD (PEALD) AlN films ... more Thermal activated atomic layer deposited (t) (ALD) and plasma enhanced (p) ALD (PEALD) AlN films were investigated for gate applications of InGaAs based metal-insulator-semiconductor devices and compared to the well-known Al2O3 based system. The roles of post-metallization annealing (PMA) and the pre-deposition treatment (PDT) by either trimethylaluminium (TMA) or NH3 were studied. In contrast to the case of Al2O3, in the case of AlN, the annealing temperature reduced interface states density. In addition, improvement of the AlN film stoichiometry and a related border traps density reduction were observed following PMA. The lowest interface states density (among the investigated gate stacks) was found for PEALD AlN/InGaAs stacks after TMA PDT. At the same time, higher values of the dispersion in accumulation were observed for AlN/InGaAs gate stacks compared to those with Al2O3 dielectric. No indium out-diffusion and the related leakage current degradation due to annealing were obser...
ABSTRACTAn energy-variable synchrotron diffraction technique is established as a novel method for... more ABSTRACTAn energy-variable synchrotron diffraction technique is established as a novel method for depth-resolved measurements of d-spacings and residual strains in polycrystalline structures. The depth sensitivity is achieved by the controlled changing the x-ray energy and, hence, the x-ray penetration into the sample. Quasi-parallel synchrotron radiation being diffracted at different depths deviates differently from the detector axis. As a result, the maximum diffraction intensity recorded in the detector is coming from a certain depth, which is energy dependent. This finding opens a way for strain measurements with high depth resolution by changing the x-ray energy in small enough steps. The developed technique is applied to characterize the electrodeposited Cu/Ni multilayers.
Rapid antigen tests (RATs) are widely used worldwide to detect SARS-CoV-2 since they are an easy-... more Rapid antigen tests (RATs) are widely used worldwide to detect SARS-CoV-2 since they are an easy-to-use kit and offer rapid results. The RAT detects the presence of the nucleocapsid protein, which is located inside the virus. However, the sensitivity of the different RATs varies between commercially available kits. The test result might change due to various factors, such as the variant type, infection date, swab’s surface, the manner in which one performs the testing and the mucus components. Here, we compare the detection limit of seven commercially available RATs by introducing them to known SARS-CoV-2 nucleocapsid protein amounts from the Omicron variant. It allows us to determine the detection limit, disregarding the influences of other factors. A lower detection limit of the RAT is necessary since earlier detection will help reduce the spread of the virus and allow faster treatment, which might be crucial for the population at risk.
An entry from the Cambridge Structural Database, the world's repository for small molecule cr... more An entry from the Cambridge Structural Database, the world's repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.
L'invention porte sur un procede de formation d'une surface nanostructuree, le procede co... more L'invention porte sur un procede de formation d'une surface nanostructuree, le procede comprenant la fourniture d'une surface nanostructuree initiale ayant un reseau de structures a rapport d'aspect eleve forme sur un substrat plan ; la formation d'un moule a empreinte negative de la surface nanostructuree initiale, le moule a empreinte negative comprenant un materiau flexible ; la deformation du moule a empreinte negative ; et l'utilisation du moule a empreinte negative deformee pour former une replique deformee de la surface nanostructuree initiale, l'etape de deformation etant effectuee au moins avant, durant ou apres l'introduction d'un materiau pour former la replique deformee dans le moule a empreinte negative.
Size effects were investigated in thin amorphous TiO2ALD films. Significant changes in film densi... more Size effects were investigated in thin amorphous TiO2ALD films. Significant changes in film density and Ti+3/Ti+4species ratio were discovered; this was attributed to surface reconstruction and formation of oxygen vacancies during the ALD process.
Proceedings of the National Academy of Sciences, 2021
Significance Dislocation edges on metal surfaces provide loosely bonded atoms, which make the sur... more Significance Dislocation edges on metal surfaces provide loosely bonded atoms, which make the surface more active for chemical corrosion and enhance the chemical reactivity. In this work, we introduce and demonstrate an autocatalytic method in which the dislocation lines in alloys can serve as a template for the growth of a different inorganic material as nanowires. We explain the formation mechanism of an incorporated system of single crystal gold(I)-cyanide nanowires on nanoporous gold during selective dealloying, using the dislocation ends in the prestrained Au-Ag alloy as catalytic centers for crystallization. This method may provide a possible route for controlling the growth direction, shape, and morphology of a crystal according to the original alloy’s slip system.
Jania sp. is an articulated coralline red alga that is abundant in the shallow waters of oceans w... more Jania sp. is an articulated coralline red alga that is abundant in the shallow waters of oceans worldwide. We have previously demonstrated that its structure is highly intricate and exhibits hierarchical organization across multiple length scales from the macro to the nano scale. Moreover, we have proven that the inner pores of its structure are helical, conveying the alga greater compliance as compared to a cylindrical configuration. Herein, we reveal new insights on the structure of Jania sp., particularly on its crystallographic variations and the internal elemental distribution of Mg and Ca. We show that the high-Mg calcite cell wall nanocrystals of Jania sp. are arranged in layers with alternating Mg contents. Moreover, we show that this non-homogenous elemental distribution assists the alga in preventing fracture caused by crack propagation. We further discover that each one of the cell wall nanocrystals in Jania sp. is not a single crystal as was previously thought, but rather comprises Mg-rich calcite nanoparticles demonstrating various crystallographic orientations, arranged periodically within the layered structure. We also show that these Mg-rich nanoparticles are present in yet another species of the coralline red algae, Corallina sp., pointing to the generality of this phenomenon. To the best of our knowledge this is a first report on the existence of Mg-rich nanoparticles in the coralline red algae mineralized tissue. We envisage that our findings on the bio-strategy found in the alga to enhance the fracture toughness will have an impact on the design of structures with superior mechanical properties. Statement of Significance: Understanding the structure-property relation in biomineralized tissues is of great importance in unveiling Nature's material design strategies, which form the basis for the development of novel structural materials. Crystallographic and elemental variations in the skeletal parts of the coralline red algae and their cumulative contribution to prevention of mechanical failure are yet poorly studied. Herein, we reveal that the high-Mg calcite cell wall nanocrystals of Jania sp. are arranged in layers with alternating Mg concentrations and reveal that this organization facilitates crack deflection, thereby preventing catastrophic fracture. We further discovered that the nanocrystals contain incoherent Mg-rich nanoparticles and suggest that they form via spinodal decomposition of the Mg-ACC precursor and self-arrange periodically throughout the alga's mineralized cell wall, a phenomenon most likely to be widespread in high-Mg calcite biomineralization.
Soft corals (Cnidaria, Anthozoa, Octocorallia, Alcyonacea) produce internal sclerites of calcium ... more Soft corals (Cnidaria, Anthozoa, Octocorallia, Alcyonacea) produce internal sclerites of calcium carbonate previously shown to be composed of calcite, the most stable calcium carbonate polymorph. Here we apply multiple imaging and physical chemistry analyses to extracted and in-vivo sclerites of the abundant Red Sea soft coral, Ovabunda macrospiculata, to detail their mineralogy. We show that this species' sclerites are comprised predominantly of the less stable calcium carbonate polymorph vaterite (>95%), with much smaller components of aragonite and calcite. Use of this mineral, which is typically considered to be metastable, by these soft corals has implications for how it is formed as well as how it will persist during the anticipated anthropogenic climate change in the coming decades. This first documentation of vaterite dominating the mineral composition of O. macrospiculata sclerites is likely just the beginning of establishing its presence in other soft corals. STATEMENT OF SIGNIFICANCE: Vaterite is typically considered to be a metastable polymorph of calcium carbonate. While calcium carbonate structures formed within the tissues of octocorals (phylum Cnidaria), have previously been reported to be composed of the more stable polymorphs aragonite and calcite, we observed that vaterite dominates the mineralogy of sclerites of Ovabunda macrospiculata from the Red Sea. Based on electron microscopy, Raman spectroscopy, and X-ray diffraction analysis, vaterite appears to be the dominant polymorph in sclerites both in the tissue and after extraction and preservation. Although this is the first documentation of vaterite in soft coral sclerites, it likely will be found in sclerites of other related taxa as well.
Semiconductors have numerous applications in both science and technology. Several methods have be... more Semiconductors have numerous applications in both science and technology. Several methods have been developed to engineer their band gap, which is one of the most important parameters of semiconductors. Here, it is shown that the incorporation of various amino acids into the crystal lattice of copper (I) oxide, akin to the way living organisms incorporate organic macromolecules into minerals during biomineralization, leads to significant shrinkage in the volume of the host unit cell and a strong blueshift in the band gap of up to ≈18%. In examining the potential location of the bio‐organic molecules within the inorganic host's lattice, a very good fit between the proposed model of incorporation and experimental findings is found. The bioinspired phenomenon of band gap widening is thought to be attributable to the void‐induced quantum confinement effect, even though observed in micrometer‐sized crystals. This hypothesis is supported by developing a tight‐binding model that is fou...
Surface reconstruction is shown to exist in nanometric amorphous films of Al2O3, causing differen... more Surface reconstruction is shown to exist in nanometric amorphous films of Al2O3, causing different short-range order at the surface.
Energy-variable synchrotron x-ray diffraction was applied to probe local structure in different k... more Energy-variable synchrotron x-ray diffraction was applied to probe local structure in different kinds of aragonitic seashells with spatial resolution. All investigated specimens revealed lattice distortions of biogenic aragonite with respect to the geological mineral. The obtained data are analyzed in terms of residual strains induced by intercalating organic macromolecules.
We compare the electrical properties of HfO2/Al2O3 nano-laminates with those of the ternary HfxAl... more We compare the electrical properties of HfO2/Al2O3 nano-laminates with those of the ternary HfxAlyO compound in metal oxide semiconductor (MOS) capacitors. The dielectrics were deposited by atomic layer deposition on InGaAs. Water, ozone, and oxygen plasma were tested as oxygen precursors, and best results were obtained using water. The total dielectric thickness was kept constant in our experiments. It was found that the effective dielectric constant increased and the leakage current decreased with the number of periods. Best results were obtained for the ternary compound. The effect of the sublayer thicknesses on the electrical properties of the interface was carefully investigated, as well as the role of post-metallization annealing. Possible explanations for the observed trends are provided. We conclude that the ternary HfxAlyO compound is more favorable than the nano-laminates approach for InGaAs based MOS transistor applications.
Thermal activated atomic layer deposited (t) (ALD) and plasma enhanced (p) ALD (PEALD) AlN films ... more Thermal activated atomic layer deposited (t) (ALD) and plasma enhanced (p) ALD (PEALD) AlN films were investigated for gate applications of InGaAs based metal-insulator-semiconductor devices and compared to the well-known Al2O3 based system. The roles of post-metallization annealing (PMA) and the pre-deposition treatment (PDT) by either trimethylaluminium (TMA) or NH3 were studied. In contrast to the case of Al2O3, in the case of AlN, the annealing temperature reduced interface states density. In addition, improvement of the AlN film stoichiometry and a related border traps density reduction were observed following PMA. The lowest interface states density (among the investigated gate stacks) was found for PEALD AlN/InGaAs stacks after TMA PDT. At the same time, higher values of the dispersion in accumulation were observed for AlN/InGaAs gate stacks compared to those with Al2O3 dielectric. No indium out-diffusion and the related leakage current degradation due to annealing were obser...
ABSTRACTAn energy-variable synchrotron diffraction technique is established as a novel method for... more ABSTRACTAn energy-variable synchrotron diffraction technique is established as a novel method for depth-resolved measurements of d-spacings and residual strains in polycrystalline structures. The depth sensitivity is achieved by the controlled changing the x-ray energy and, hence, the x-ray penetration into the sample. Quasi-parallel synchrotron radiation being diffracted at different depths deviates differently from the detector axis. As a result, the maximum diffraction intensity recorded in the detector is coming from a certain depth, which is energy dependent. This finding opens a way for strain measurements with high depth resolution by changing the x-ray energy in small enough steps. The developed technique is applied to characterize the electrodeposited Cu/Ni multilayers.
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