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Plasma produced from molten-tin microdroplets generates extreme ultraviolet light for state-of-the-art nanolithography. Currently, CO2 lasers are used to drive the plasma. In the future, solid-state mid-infrared lasers may instead be used to efficiently pump the plasma. Such laser systems have promise to be more compact, better scalable, and have higher wall-plug efficiency. In this Topical Review, we present recent findings made at the Advanced Research Center for Nanolithography (ARCNL) on using 1 and 2 µm wavelength solid-state lasers for tin target preparation and for driving hot and dense plasma. The ARCNL research ranges from advanced laser development, studies of fluid dynamic response of droplets to impact, radiation-hydrodynamics calculations of, e.g. ion ‘debris’, (EUV) spectroscopic studies of tin laser-produced-plasma as well as high-conversion efficiency operation of 2 µm wavelength driven plasma.

Considered to be a field that is continuously growing, epitranscriptomics analyzes the modifications that occur in RNA transcripts and their downstream effects. As epigenetic modifications found in DNA and histones exhibit specific roles on various biological processes, also epitranscriptomic marks control gene expression patterns that are crucial for proper cell proliferation, differentiation and tissue development. Thus, various epitranscriptomic signatures have been identified to play specific roles during stem cell differentiation towards the neuronal and glial lineages, axonal guidance, synaptic plasticity, thus leading to the development of the mature brain tissue. Here we describe in-depth molecular mechanism underlying the most important RNA modifications with emerging roles in the nervous system.

Plasma produced from molten-tin microdroplets generates extreme ultraviolet light for state-of-the-art nanolithography. Currently, CO2 lasers are used to drive the plasma. In the future, solid-state mid-infrared lasers may instead be used to efficiently pump the plasma. Such laser systems have promise to be more compact, better scalable, and have higher wall-plug efficiency. In this Topical Review, we present recent findings made at the Advanced Research Center for Nanolithography (ARCNL) on using 1 and 2 mu m wavelength solid-state lasers for tin target preparation and for driving hot and dense plasma. The ARCNL research ranges from advanced laser development, studies of fluid dynamic response of droplets to impact, radiation-hydrodynamics calculations of, e.g. ion 'debris', (EUV) spectroscopic studies of tin laser-produced-plasma as well as high-conversion efficiency operation of 2 mu m wavelength driven plasma.

Background: The neuromuscular system is able to quickly adapt to exercise-induced muscle damage (EIMD), such that it is less affected by subsequent damaging exercise, a phenomenon known as the repeated bout effect (RBE). The objective was to determine whether the mechanical properties of the quadriceps, as evaluated by shear wave elastography (SWE), were less affected when a second bout of eccentric-biased exercise was performed 2 weeks later. It was hypothesized that the first bout would confer protection against extensive muscle damage through an adaptation of the muscle stiffness before the second bout (i.e., higher muscle stiffness).Methods: Sixteen males performed two identical bouts of downhill walking separated by 2 weeks (45 min at 4.5 km.h−1; gradient: 25%; load: 30% of the body mass). Rectus femoris (RF) and vastus lateralis (VL) resting shear elastic modulus (µ) and EIMD symptoms were measured before and up to 7 days following the exercise bouts. Changes in neuromuscular function was evaluated by maximal voluntary contraction torque, voluntary activation level, evoked mechanical response to single and double (10 and 100 Hz doublets) electrical stimulation. An index of protection (IP) was calculated for EIMD symptoms to assess magnitude the RBE.Results: EIMD symptoms were less affected after the second than the first exercise bout. RF and VL-µ increased (p < 0.001) only after the first exercise. RF µ was elevated up to 2 weeks after the end of the first exercise (p < 0.001) whereas VL µ was only increased up to 24 h. The increase in µ observed 2 weeks after the end of the first exercise was correlated with the IP; i.e., attenuation of alterations in muscle µ, 10 Hz-doublet amplitude and rate of torque development after the second exercise bout (p < 0.05).Conclusion: We showed that muscle µ assessed by SWE was sensitive to the RBE, with a differential effect between VL and RF. The persistent increase in µ was associated with the attenuation of neuromuscular impairments observed after the second bout, suggesting that the increased muscle stiffness could be a “protective” adaptation making muscles more resistant to the mechanical strain associated to eccentric contractions.

Gaseous sulfuric acid (H2SO4) is known as one of the key precursors for atmospheric new particle formation (NPF) processes, but its measurement remains challenging. Therefore, a proxy method that is able to derive gaseous sulfuric acid concentrations from parameters that can be measured relatively easily and accurately is highly desirable for the atmospheric chemistry community. Although such methods are available for clean atmospheric environments, a proxy that works well in a polluted atmosphere, such as that found in Chinese megacities, is yet to be developed. In this study, the gaseous sulfuric acid concentration was measured in February–March 2018, in urban Beijing using a nitrate based – long time-of-flight chemical ionization mass spectrometer (LToF-CIMS). A number of atmospheric parameters were recorded concurrently including the ultraviolet radiation B (UVB) intensity, the concentrations of O3, NOx (sum of NO and NO2), SO2, and HONO, and aerosol particle number size distributions. A proxy for atmospheric daytime gaseous sulfuric acid concentration was derived via a statistical analysis method using the UVB intensity, [SO2], the condensation sink (CS), [O3], and [HONO] (or [NOx]) as the predictor variables, where square brackets denote the concentrations of the corresponding species. In this proxy method, we considered the formation of gaseous sulfuric acid from reactions of SO2 and OH radicals during the daytime, and the loss of gaseous sulfuric acid due to its condensation onto the preexisting particles. In addition, we explored the formation of OH radicals from the conventional gas-phase photochemistry using O3 as a proxy and from the photolysis of HONO using HONO (and subsequently NOx) as a proxy. Our results showed that the UVB intensity and [SO2] are dominant factors in the production of gaseous sulfuric acid, and that the simplest proxy could be constructed with the UVB intensity and [SO2] alone. When the OH radical production from both homogenously and heterogeneously formed precursors were considered, the relative errors were reduced by up to 20 %.

Secondary aerosol formation in the aging process of primary emission is the main reason for haze pollution in eastern China. Pollution evolution with photochemical age was studied for the first time at a comprehensive field observation station during winter in Beijing. The photochemical age was used as an estimate of the time scale attributed to the aging process and was estimated from the ratio of toluene to benzene in this study. A low photochemical age indicates a fresh emission. The photochemical age of air masses during new particle formation (NPF) days was lower than that on haze days. In general, the strongest NPF events, along with a peak of the formation rate of 1.5 nm(J(1.5)) and 3 nmparticles (J(3)), were observed when the photochemical age was between 12 and 24 h while rarely took place with photochemical ages less than 12 h. When photochemical age was larger than 48 h, haze occurred and NPF was suppressed. The sources and sinks of nanoparticles had distinct relation with the photochemical age. Our results show that the condensation sink (CS) showed a valley with photochemical ages ranging from 12 to 24 h, while H2SO4 concentration showed no obvious trend with the photochemical age. The high concentrations of precursor vapours within an air mass lead to persistent nucleation with photochemical age ranging from 12 to 48 h in winter. Coincidently, the fast increase of PM2.5 mass was also observed during this range of photochemical age. Noteworthy, CS increased with the photochemical age on NPF days only, which is the likely reason for the observation that the PM2.5 mass increased faster with photochemical age on NPF days compared with other days. The evolution of particles with the photochemical age provides new insights into understanding how particles originating from NPF transform to haze pollution. (C) 2020 Elsevier B.V. All rights reserved.

New Particle Formation (NPF) is regularly observed to occur in heavily polluted Chinese megacities. However, in these NPF events, the survival probability of small clusters into larger aerosol particles is higher than theoretically predicted. One explanation for this could be that the loss rate of clusters due to scavenging by pre-existing particles, which is described by condensation sink, is lower than expected. In this study, we describe the loss of clusters due to condensation sink by using heterogeneous nucleation theory, and investigate if ineffectiveness of heterogeneous nucleation can result in a significantly lowered effective condensation sink. We find that in principle it is possible that due to properties of the system there is no heterogeneous nucleation, and this can significantly influence the magnitude of effective condensation sink and thus increase the survival probability of clusters.

The climate and air quality effects of aerosol particles depend on the number and size of the particles. In urban environments, a large fraction of aerosol particles originates from anthropogenic emissions. To evaluate the effects of different pollution sources on air quality, knowledge of size distributions of particle number emissions is needed. Here we introduce a novel method for determining size-resolved particle number emissions, based on measured particle size distributions. We apply our method to data measured in Beijing, China, to determine the number size distribution of emitted particles in a diameter range from 2 to 1000 nm. The observed particle number emissions are dominated by emissions of particles smaller than 30 nm. Our results suggest that traffic is the major source of particle number emissions with the highest emissions observed for particles around 10 nm during rush hours. At sizes below 6 nm, clustering of atmospheric vapors contributes to calculated emissions. The comparison between our calculated emissions and those estimated with an integrated assessment model GAINS (Greenhouse Gas and Air Pollution Interactions and Synergies) shows that our method yields clearly higher particle emissions at sizes below 60 nm, but at sizes above that the two methods agree well. Overall, our method is proven to be a useful tool for gaining new knowledge of the size distributions of particle number emissions in urban environments and for validating emission inventories and models. In the future, the method will be developed by modeling the transport of particles from different sources to obtain more accurate estimates of particle number emissions.

Se llevo a cabo el análisis de estabilidad de taludes mediante diferentes software para tal fin, con la finalidad de hacer un comparativo entre los resultados y de esta forma sugerir el software de mejor entendimiento y más fácil de utilizar por parte de los usuarios. Introducción Objetivos 2.1 Objetivo general 2.2 Objetivo específico Alcance Justificación Marco teórico y conceptual 5.1 Definiciones 5.2 Tipos de falla de taludes en suelos 5.3 Tipos de falla de taludes en rocas 5.4 Movimientos de laderas 5.5 Métodos de análisis de taludes 5.5.1 Métodos utilizados para el comparativo 5.5.2 Métodos rigurosos 5.5.3 Métodos numéricos 5.5.4 Software 5.6 Métodos de estabilización Caso de estudio 6.1 Información preliminar Tramo 6 Km 79 + 625 vía Anapoima Mosquera – Cundinamarca 6.1.1 Topografía 6.1.2 Hidrología 6.1.3 Geología 6.1.4 Condiciones antes de construcción 6.1.5 Sección de análisis 6.2 Perfil estratigráfico 6.2.1 Base de datos – Instituto Nacional de Vías (INVIAS) 6.2.2 Ensayos de campo 6.2.3 Ensayos de laboratorio 6.2.4 Referencias Bibliográficas 6.3 Análisis de estabilidad mediante software 6.3.1 Software 1 – SLIDE 6.3.2 Software 2 –SLOPE 6.3.3 Software 3 – GEO 5 6.4 Análisis comparativo de condiciones de talud inicial Análisis de estabilidad con la ampliación vial 7.1 Solución por medio de sofware 7.1.1 Software 1 – SLIDE 7.1.2 Software 2 – SLOPE 7.1.3 Software 3 – GEO 5 Análisis comparativo de las soluciones entre software SLIDE, SLOPE y GEO5 Conclusiones y recomendaciones Anexos: Comparativo resultados laboratorio, SPT y Bibliografía Referencias Bibliográficas Slope stability analysis was carried out using different software for this purpose, in order to make a comparison between the results and in this way suggest the software that is better understood and easier to use by users. Pregrado L'analyse de la stabilité des pentes a été réalisée à l'aide de différents logiciels à cet effet, afin de faire une comparaison entre les résultats et ainsi suggérer le logiciel mieux compris et plus facile à utiliser par les utilisateurs.

A power and area efficient two-step hybrid voltage–time ADC achieves a 4-GS/s conversion speed and 39.9-dB SNDR in 28-nm CMOS. Two pipelined time-based converters (TBCs) with a thermometer capacitive DAC (CDAC) in the ADC lead to a high-speed and low-power operation. The pipelined architecture splits the full ADC resolution, thus relaxing the TBC complexity. The TBC consists of a voltage-domain comparator, a current-source-based voltage-to-time converter (VTC), and a ring oscillator (RO)-based time-to-digital converter (TDC) with feedforward and 2 $\times $ interpolation that achieves high conversion speed and good linearity simultaneously. The prototype ADC is fabricated in a standard 28-nm CMOS process with an active area of only 0.017mm2. The measured SNDR and SFDR are 39.9 and 47.8 dB with a Nyquist input at 4 GS/s. The FoMW and FoMS are 39.3 fJ/conv-step and 152.2 dB, respectively.

Top-down ultraviolet photodissociation (UVPD) allows greater sequence coverage than any other currently available method, often fracturing the vast majority of peptide bonds in whole proteins. At the same time, UVPD can be used to dissociate noncovalent complexes assembled from multiple proteins without breaking any covalent bonds. Although the utility of these experiments is unquestioned, the mechanism underlying these seemingly contradictory results has been the subject of many discussions. Herein, some fundamental considerations of photochemistry are briefly summarized within the context of a proposed mechanism that rationalizes the experimental results obtained by UVPD. Considerations for future instrument design, in terms of wavelength choice and power, are briefly discussed. Graphical Abstract ᅟ.

The limb darkening and center-to-limb variation of the continuum polarization is calculated for a grid of one-dimensional stellar model atmospheres and for a wavelength range between 300 and 950 nm. Model parameters match those of the transiting stars taken from the NASA exoplanet archive. The limb darkening of the continuum radiation for these stars is shown to decrease with the rise in their effective temperature. For the lambda = 370 nm wavelength, which corresponds to the maximum of the Johnson-Cousins UX filter, the limb darkening values of the planet transiting stars lie in a range between 0.03 and 0.3. The continuum linear polarization depends not only on the effective temperature of the star but also on its gravity and metallicity. Its value decreases for increasing values of these parameters. In the UX band, the maximum linear polarization of stars with transiting planets amounts to 4%, while the minimum value is approximately 0.3%. The continuum limb darkening and the linear polarization decrease rapidly with wavelength. At the R band maximum (lambda = 700 nm), the linear polarization close to the limb is in fact two orders of magnitude smaller than in the UX band. The center- to-limb variation of the continuum intensity and the linear polarization of the stars with transiting planets can be approximated, respectively, by polynomials of the fourth and the sixth degree. The coefficients of the polynomials, as well as the IDL procedures for reading them, are available in electronic form. It is shown that there are two classes of stars with high linear polarization at the limb. The first one consists of cold dwarfs. Their typical representatives are HATS-6, Kepler-45, as well as all the stars with similar parameters. The second class of stars includes hotter giants and subgiants. Among them we have CoRoT-28, Kepler-91, and the group of stars with effective temperatures and gravities of approximately 5000 K and 3.5, respectively.

Plant-derived natural products have long been considered a valuable source of lead compounds for drug development. Natural extracts are usually composed of hundreds to thousands of metabolites, whereby the bioactivity of natural extracts can be represented by synergism between several metabolites. However, isolating every single compound from a natural extract is not always possible due to the complex chemistry and presence of most secondary metabolites at very low levels. Metabolomics has emerged in recent years as an indispensable tool for the analysis of thousands of metabolites from crude natural extracts, leading to a paradigm shift in natural products drug research. Analytical methods such as mass spectrometry (MS) and nuclear magnetic resonance (NMR) are used to comprehensively annotate the constituents of plant natural products for screening, drug discovery as well as for quality control purposes such as those required for phytomedicine. In this review, the current advancements in plant sample preparation, sample measurements, and data analysis are presented alongside a few case studies of the successful applications of these processes in plant natural product drug discovery.

Two-photon light-sheet microscopy (2P-SPIM) provides a unique combination of advantages for fast and deep fluorescence imaging in live tissues. Detecting coherent signals such as second-harmonic generation (SHG) in 2P-SPIM in addition to fluorescence would open further imaging opportunities. However, light-sheet microscopy involves an orthogonal configuration of illumination and detection that questions the ability to detect coherent signals. Indeed, coherent scattering from micron-sized structures occurs predominantly along the illumination beam. By contrast, point-like sources such as SHG nanocrystals can efficiently scatter light in multiple directions and be detected using the orthogonal geometry of a light-sheet microscope. This study investigates the suitability of SHG light-sheet microscopy (SHG-SPIM) for fast imaging of SHG nanoprobes. Parameters that govern the detection efficiency of KTiOPO4 and BaTiO3 nanocrystals using SHG-SPIM are investigated theoretically and experimentally. The effects of incident polarization, detection numerical aperture, nanocrystal rotational motion, and second-order susceptibility tensor symmetries on the detectability of SHG nanoprobes in this specific geometry are clarified. Guidelines for optimizing SHG-SPIM imaging are established, enabling fast in vivo light-sheet imaging combining SHG and two-photon excited fluorescence. Finally, microangiography was achieved in live zebrafish embryos by SHG imaging at up to 180 frames per second and single-particle tracking of SHG nanoprobes in the blood flow., ACS Photonics, 7 (4), ISSN:2330-4022

Efficient and reliable on-chip optical amplifiers and light sources would enable versatile integration of various active functionalities on the silicon platform. Although lasing on silicon has been demonstrated with semiconductors by using methods such as wafer bonding or molecular beam epitaxy, cost-effective mass production methods for CMOS-compatible active devices are still lacking. Here, we report ultra-high on-chip optical gain in erbium-based hybrid slot waveguides with a monolithic, CMOS-compatible and scalable atomic-layer deposition process. The unique layer-by-layer nature of atomic-layer deposition enables atomic scale engineering of the gain layer properties and straightforward integration with silicon integrated waveguides. We demonstrate up to 20.1 ± 7.31 dB/cm and at least 52.4 ± 13.8 dB/cm net modal and material gain per unit length, respectively, the highest performance achieved from erbium-based planar waveguides integrated on silicon. Our results show significant advances towards efficient on-chip amplification, opening a route to large-scale integration of various active functionalities on silicon., Realizing efficient on-chip amplification in silicon is challenging due to either non-compatible integration or small gain per unit length of the amplifier material. Here, the authors report ultra-high on-chip optical gain in erbium-based hybrid silicon nitride slot waveguides with a monolithic, CMOS-compatible and scalable atomic-layer deposition process.

Spectral dependence of Lamb coupling constant C is experimentally investigated in an InGaAlAs Quantum Wells active medium. An Optically-Pumped Vertical-External-Cavity Surface-Emitting Laser is designed to sustain the oscillation of two orthogonally polarized modes sharing the same active region while separated in the rest of the cavity. This laser design enables to tune independently the two wavelengths and, at the same time, to apply differential losses in order to extract without any extrapolation the actual coupling constant. C is found to be almost constant and equal to 0.84 +/- 0.02 for frequency differences between the two eigenmodes ranging from 45 GHz up to 1.35 THz. (C) 2019 Optical Society of America under the terms of the OSA Open Access Publishing Agreement