Search

Entangled two-photon absorption (ETPA) could form the basis of nonlinear quantum spectroscopy at very low photon fluxes, since, at sufficiently low photon fluxes, ETPA scales linearly with the photon flux. When different pairs start to overlap temporally, accidental coincidences are thought to give rise to a "classical" quadratic scaling that dominates the signal at large photon fluxes and, thus, recovers a supposedly classical regime, where any quantum advantage is thought to be lost. Here, we scrutinize this assumption and demonstrate that quantum-enhanced absorption cross sections can persist even for very large photon numbers. To this end, we use a minimal model for quantum light, which can interpolate continuously between the entangled pair and a high-photon-flux limit, to analytically derive ETPA cross sections and the intensity crossover regime. We investigate the interplay between spectral and spatial degrees of freedom and how linewidth broadening of the sample impacts the experimentally achievable enhancement. [ABSTRACT FROM AUTHOR]

Miniaturized photoionization detectors (PIDs) are used in conjunction with gas chromatography systems to detect volatile compounds in gases by collecting the current from the photoionized gas analytes. PIDs should be inexpensive and compatible with a wide range of analyte species. One such PID is based on the formation of a He plasma in a dielectric barrier discharge (DBD), which generates vacuum UV (VUV) photons from excited states of He to photoionize gas analytes. There are several design parameters that can be leveraged to increase the ionizing photon flux to gas analytes to increase the sensitivity of the PID. To that end, the methods to maximize the photon flux from a pulsed He plasma in a DBD-PID were investigated using a two-dimensional plasma hydrodynamics model. The ionizing photon flux originated from the resonance states of helium, He(3P) and He(21P), and from the dimer excimer He2*. While the photon flux from the resonant states was modulated over the voltage pulse, the photon flux from He2* persisted long after the voltage pulse passed. Several geometrical optimizations were investigated, such as using an array of pointed electrodes. However, increasing the capacitance of the dielectric enclosing the plasma chamber had the largest effect on increasing the VUV photon fluence to gas analytes. [ABSTRACT FROM AUTHOR]

Both spontaneous Raman scattering and stimulated Raman scattering (SRS) are cornerstones of modern photonics, spectroscopy, and imaging. However, a unified understanding of the ultimate detectability of Raman scattering is lacking, due to both historical and technical reasons. Starting from quantum electrodynamics, we formulate the fundamental detectability for both spontaneous Raman scattering and SRS. The key concept is recognizing spontaneous Raman scattering as stimulated Raman process driven by vacuum field fluctuation. A simple and unified expression, Eq. (17), is derived, which can be depicted on a two-dimensional phase-diagram-like graph with inherent symmetry. It turns out that the particle nature of light dictates the ultimate detectability of spontaneous Raman scattering, which can be represented by a line on this detectability diagram. Importantly, if provided with a reasonably strong Stokes photon flux, SRS can breach this fundamental limit and open uncharted territory of drastically accelerated measurement speed and much lower detection concentration relevant to biological imaging. Such new territory in the detectability diagram is otherwise forbidden by the spontaneous counterpart. Diagrammatical analysis explains the empirical observations, provides quantitative insights, and makes new predictions. Notably, recent experimental applications of SRS microscopy can almost entirely be captured by this diagram, further supporting the explanatory power of the theory. Thus, this unified diagrammatic approach outlines a framework to understand all Raman-based measurement and provides a theoretical explanation for the remarkable utility of the emerging SRS microscopy. [ABSTRACT FROM AUTHOR]

We investigated the impact of carrier trapping on the carrier lifetime of metal halide perovskite materials, which are key to solar cell production. We examined NH3CH3PbI3 (MAPbI3), NH3CH3PbBr3 (MAPbBr3), and CsPbBr3 using continuous-wave (CW) laser illumination during microwave photoconductivity decay (μ-PCD) measurements. Traditional pulsed light excitation falls short of mirroring solar cell operating conditions, owing to carrier trapping. Implementing CW laser illumination provides a more accurate estimation of the carrier lifetimes under operational conditions. With an increased photon flux from the CW laser, the μ-PCD decay curves changed, indicating reduced recombination via traps. The experiments revealed extended carrier lifetimes under continuous light for the MAPbI3 polycrystal. This suggests that CW lasers can mitigate trapping effects on carrier lifetime measurements. For the other samples, carrier trapping had a negligible effect on the measured carrier lifetimes. We believe that these findings will aid in the design of perovskite-based devices. [ABSTRACT FROM AUTHOR]

Despite being outside of the traditionally defined photosynthetically active radiation (PAR) waveband (400–700 nm), far-red (FR; 700–799 nm) light can increase photosynthesis and induce shade-avoidance responses, which increases light interception and thus, whole-plant growth. However, it is unclear how the promotion of growth from FR light depends on PAR wavebands and specifically how the substitution of red light (600–699 nm) with green light (500–599 nm) influences the efficacy of FR light on increasing shoot biomass accumulation. To determine this, we grew red- and green-leaf lettuce (Lactuca sativa) at a fixed total photon flux density (PFD) with 12 different fractions of red, green, and FR light and the same PFD of blue (400–499 nm) light. We postulated that decreasing the red:FR by substituting FR light for green light, red light, or both would increase shoot fresh mass (FM) until a fraction beyond which growth (but not leaf area) would begin to decrease. Indeed, the substitution of red with FR light increased the leaf area of both cultivars, but FM was greatest under an FR fraction [FR/(R+FR)] of approximately 0.25. Under the greatest FR PFD, FM was similar to lettuce grown without FR light, despite having greater leaf surface area for light interception. Green light had less of an effect on leaf expansion and FM than FR light, and plant diameter and leaf area of red-leaf 'Rouxai' were the greatest when green light fully replaced red light at the highest FR PFD. We conclude that under a modest light intensity and blue PFD, a spectrum that includes up to 25% of far-red photons can increase leaf area and biomass accumulation. While leaf area may continue to increase at higher far-red fractions, fresh mass does not, and plant quality begins to deteriorate. [ABSTRACT FROM AUTHOR]

Product selectivity of solar‐driven CO2 reduction and H2O oxidation reactions has been successfully controlled by tuning the spatial distance between Pt/Au bimetallic active sites on different crystal facets of CeO2 catalysts. The replacement depth of Ce atoms by monatomic Pt determines the distance between bimetallic sites, while Au clusters are deposited on the surface. This space configuration creates a favourable microenvironment for the migration of active hydrogen species (*H). The *H is generated via the activation of H2O on monatomic Pt sites and migrate towards Au clusters with a strong capacity for CO2 adsorption. Under concentrated solar irradiation, selectivity of the (100) facet towards CO is 100 %, and the selectivity of the (110) and (111) facets towards CH4 is 33.5 % and 97.6 %, respectively. Notably, the CH4 yield on the (111) facet is as high as 369.4 μmol/g/h, and the solar‐to‐chemical energy efficiency of 0.23 % is 33.8 times higher than that under non‐concentrated solar irradiation. The impacts of high‐density flux photon and thermal effects on carriers and *H migration at the microscale are comprehensively discussed. This study provides a new avenue for tuning the spatial distance between active sites to achieve optimal product selectivity. [ABSTRACT FROM AUTHOR]

Two‐photon high‐speed fluorescence calcium imaging stands as a mainstream technique in neuroscience for capturing neural activities with high spatiotemporal resolution. However, challenges arise from the inherent tradeoff between acquisition speed and image quality, grappling with a low signal‐to‐noise ratio (SNR) due to limited signal photon flux. Here, a contrast‐enhanced video‐rate volumetric system, integrating a tunable acoustic gradient (TAG) lens‐based high‐speed microscopy with a TAG‐SPARK denoising algorithm is demonstrated. The former facilitates high‐speed dense z‐sampling at sub‐micrometer‐scale intervals, allowing the latter to exploit the spatial redundancy of z‐slices for self‐supervised model training. This spatial redundancy‐based approach, tailored for 4D (xyzt) dataset, not only achieves >700% SNR enhancement but also retains fast‐spiking functional profiles of neuronal activities. High‐speed plus high‐quality images are exemplified by in vivo Purkinje cells calcium observation, revealing intriguing dendritic‐to‐somatic signal convolution, i.e., similar dendritic signals lead to reverse somatic responses. This tailored technique allows for capturing neuronal activities with high SNR, thus advancing the fundamental comprehension of neuronal transduction pathways within 3D neuronal architecture. [ABSTRACT FROM AUTHOR]

Single-photon avalanche diodes (SPADs) are critical components in low-light-level sensing and photonic quantum information applications. For these, it is often necessary that a full characterization of the SPAD is performed, for which a key metric is the afterpulse probability. This study provides a detailed comparison of the common synchronized and non-synchronized methods used to measure afterpulse probability. Measurements on a single SPAD reveal inconsistencies between the afterpulse probabilities obtained by the two methods. By re-deriving the equations from first principles, the discrepancy is traced to the analysis approach for the non-synchronized experiment. An improved analysis approach is presented, leading to better agreement between the non-synchronized and synchronized methods. The study also provides guidance on the experimental conditions required for the valid application of both methods, along with a detailed analysis of the limitations of the non-synchronized method under high photon flux. These findings offer a more accurate approach for characterizing afterpulse probability and for reconciling the results of two methods, which enables better quantification of SPAD performance. [ABSTRACT FROM AUTHOR]

Toroidal vortices, or vortex rings, are torus‐shaped vortices observed in various fluid systems. Recently, optical toroidal vortices, novel solutions to Maxwell's equations, have been experimentally observed (Nat. Photonics, 2022, 16, 519). Thus, their nanoplasmonic counterparts, namely plasmonic toroidal vortices, are highly anticipated. This study aims to elucidate the generation and manifestation of plasmonic toroidal vortices. To achieve this, a technique involving the illumination of a gold nanotorus with a radially‐polarized beam is employed. Notably, the plasmonic toroidal vortices exhibit a distinct photon flow trajectory along the minor radius of a nanotorus. This work presents an advancement in toroidal vortices within the plasmonic regime. [ABSTRACT FROM AUTHOR]

Adding far-red (FR) photons to a constant photosynthetic photon flux density (PPFD) alters photosynthesis, leaf morphology, and biomass accumulation of horticultural plants. However, the influences of partially substituting PPFD with FR photons under the same extended PPFD (ePPFD) on the growth of greenhouse lettuce (Lactuca sativa L.) is still unknown. In this study, loose-leaf lettuce ('Dasusheng') grown in a greenhouse in the fall was implemented using six supplementary light treatments including white plus red (WR) LEDs with substitutive FR photon flux density at 0, 10, 30, 50, 70, and 90 mmol·m22·s21 under the same ePPFD (WR139, WR129+FR10, WR109+FR30, WR89+FR50, WR69+FR70, and WR49+FR90, respectively). Lettuce grown with natural light only was designated as NL. The results indicated that supplementary light led to lower plant height, thicker leaves, higher biomass accumulation, higher vitamin C content, higher starch content, and higher total soluble sugar content in lettuce compared with those of lettuce grown under NL. Lettuce grown under WR139 resulted in a 40.0% decrease in plant height, 66.8% increase in leaf thickness, and 34.1% increase in shoot fresh weight compared with those of lettuce grown under NL. No significant differences were observed in leaf width, specific leaf area, shoot fresh weight, root fresh weight, shoot dry weight, root dry weight, soil plant analysis development value, apparent quantum yield, soluble protein content, and light use efficiency of lettuce among the WR139, WR129+FR10, and WR109+FR30 treatments. Furthermore, decreased trends were observed in the biomass accumulation and maximum net photosynthetic rate of lettuce with the increased substituted FR photon flux density. However, an opposite trend was found in the maximum photochemical quantum yield. In conclusion, partially substituting PPFD with FR photons at 10 to 30 lmol·m22·s21 had similar effects on the biomass accumulation and nutritional quality of greenhouse lettuce. The FR photons should be applied with the consideration of photon flux density because the results also demonstrated negative effects of excess substituted FR photons for PPFD. [ABSTRACT FROM AUTHOR]

Photoinhibition, a common physiological obstacle in forest regeneration, results from rapid light elevations after removing upper-layer trees, thereby impeding sapling growth and survival. The leaf mass per area (LMA), which reflects the current light environment, may predict saplings' responses to future elevations in light intensity. However, the relationship between the LMA and photoinhibition sensitivity in boreal forest evergreen conifers remains unclear. In this study, we explored whether the LMA was related to photoinhibition sensitivity in A. sachalinensis saplings. Saplings with a high LMA exhibited higher excitation pressure (1−qP) under the current light environment, leading to increased stress even at low relative light intensities of 3%–17%. A model illustrating the dependence of photosynthetic physiological parameters on the photosynthetic photon flux density (PPFD) revealed that 1−qP significantly decreased with an increasing LMA, while the electron transfer rate (ETR) and non-photochemical quenching (NPQ) significantly increased. Additionally, regardless of the LMA, 1−qP reached near saturation (≈1.0) at a PPFD of 1000 μmol m−2 s−1, likely owing to the inefficient consumption of excess energy by electron transfer, as indicated by the low maximum ETR (approximately 25 μmol m−2 s−1). These findings suggest that although A. sachalinensis exhibits high sensitivity to photoinhibition, a high LMA may reflect physiological acclimation to forthcoming elevations in light exposure, thereby reducing the susceptibility to photoinhibition at present and in the future. [ABSTRACT FROM AUTHOR]

Asterarcys quadricellularis strain AQYS21, a green microalga isolated from the brackish waters near Manseong-ri Black Sand Beach in Korea, shows considerable potential as a source of bioactive compounds and biofuels. Therefore, this study analyzed the morphological, molecular, and biochemical characteristics of this strain; optimized its cultivation conditions; and evaluated its suitability for biodiesel production. Morphological analysis revealed characteristics typical of the Asterarcys genus: spherical to ellipsoidal cells with pyrenoid starch plates and mucilage-embedded coenobia. Additionally, features not previously reported in other A. quadricellularis strains were observed. These included young cells with meridional ribs and an asymmetric spindle-shaped form with one or two pointed ends. Molecular analysis using small-subunit rDNA and tufA sequences confirmed the identification of the strain AQYS21. This strain showed robust growth across a wide temperature range, with optimal conditions at 24 °C and 88 µmol m−2s−1 photon flux density. It was particularly rich in ω-3 α-linolenic acid and palmitic acid. Furthermore, its biodiesel properties indicated its suitability for biodiesel formulations. The biomass of this microalga may serve as a viable feedstock for biodiesel production and a valuable source of ω-3 fatty acids. These findings reveal new morphological characteristics of A. quadricellularis, enhancing our understanding of the species. [ABSTRACT FROM AUTHOR]

IVB–VIA transition metal dichalcogenides (TMDs) MX2 (M = Zr, Hf; X = S, Se) and related Janus MXY (M = Zr, Hf; X = S, Y = Se) have garnered significant attention due to their unique optoelectronic properties. To further explore their potential in flexible photonics, their mechanical, band dispersion, and optical dielectric properties using orbital hybrid theory are investigated. The results reveal that the out‐of‐plane linear compression resistance of these materials is considerably lower than their in‐plane resistance, primarily because van der Waals interactions are much weaker compared to ionic bond interactions. This characteristic makes them less susceptible to external pressure and torsional forces, positioning them as promising candidates for flexible optoelectronic devices. Furthermore, the presence of multiple energy bands at the same momentum state suggests a tendency toward metal–insulator transitions. Notably, the materials exhibit a high photon flux, indicating robust photoelectric conversion capabilities, making them suitable for applications in photoelectric transducers. This study not only deepens the understanding of the optoelectronic and mechanical properties of IVB–VIA TMD materials, but also offers theoretical guidance for the development and application of flexible optoelectronic devices based on IVB‐VIA TMDs and related Janus materials. [ABSTRACT FROM AUTHOR]

Reliable net primary production (NPP) estimations of kelp forests are important to evaluate their C-fixation potential. Photosynthetic oxygen measurements can be converted to C-fixation using photosynthetic quotients (PQs). Although there is a known high variability in PQs, the extent and the consequences for NPP is understudied in kelp species. Thus, the present study aimed (i) to quantify the variability of PQs, (ii) to model NPP and (iii) to assess the impact of warming on both. The kelp, Laminaria hyperborea, was studied near the island of Helgoland (North Sea, Germany) along a depth gradient (2, 4, 6 m below mean low water spring tide) across all four seasons. Blade discs were cultivated during at least 6 days per season under simulated ambient photosynthetic photon flux density (PPFD) and temperature conditions and, in parallel, in a warming scenario (+ 4°C). PQs were calculated from parallel oxygen production and 14C-fixation measurements at saturating PPFD at the end of the incubation period. Seasonal PQs varied between 1.7 and 4.4, with highest values in summer due to increased oxygen production. The warming scenario stimulated C-fixation in most seasons, lowering the PQ in comparison to ambient temperature conditions, while collection depth had no significant effect on PQs. The seasonal PQs were used to model daily NPP rates for kelp standing stock at 4 m depth. These daily NPP rates were compared between temperature treatments and with daily NPP rates based on fixed PQs. The warming scenario had a stimulating effect on daily NPP rates in the high-light season spring. In the low-light season autumn, warming resulted in negative daily NPP rates, as the high respiration rates could not be compensated by gross photosynthesis. Overall, annual NPP rate under warming conditions (347 g C m-2 yr-1) was 14% higher than the annual NPP rate under ambient conditions (303 g C m-2 yr-1). Modelling daily NPP with fixed PQs, which neglects the seasonal variation of the PQs, led to a high overestimation of up to 255%. We, therefore, recommend modelling NPP rates not with a fixed PQ, but with seasonal PQs determined under different temperature scenarios in order to obtain reliable future predictions. [ABSTRACT FROM AUTHOR]

In this study, the maximal reduction of neutron leakage into the treatment room and bunker walls was evaluated by placing three stratified layers of PL/hBN and PL/B4C at distinct spatial coordinates within a medical linear accelerator facility. Simulations were conducted using the MCNPX code, focusing on "Photon flux per therapeutic X-ray dose" and "Neutron leakage and neutron density per therapeutic X-ray dose." The results indicated that adding PL/hBN and PL/B4C layers achieves the desired dose with a lower photon flux. The PL/hBN layer in a better proportion reduced flux compared to the PL/B4C layer. It was found that the PL/hBN layer can reduce neutron leakage and density in the air by up to 60.43 % and 50.08 %, respectively, while the PL/B4C layer achieved reductions of 44.32 % and 34.86 %. Additionally, reductions in neutron leakage and density within the bunker walls reached 95.61 % and 86.22 % with the PL/hBN shield, and up to 80.46 % and 70.59 % with the PL/B4C shield. These findings underscore the effectiveness of these layered neutron shielding measures in reducing neutron populations within the treatment room air and enhancing bunker protection. [ABSTRACT FROM AUTHOR]

Photochromic yttrium oxyhydride, YHO, has excellent properties as a responsive solar control material, in particular due to its color-neutral darkening. In this work, we have investigated YHO's spectral response to the solar AM 1.5 spectrum to evaluate how the total photon activation flux changes as a function of thickness and wavelength. The calculations are based on ellipsometry measurements in the 240–2000 nm range. Our results show that the UV light absorption saturates at around 400 nm thick film, while blue light (>400 nm) continues to provide photoactivation well beyond 1 μm thickness. Understanding the spectral response and absorption per unit time of activating photons as a function of material thickness is important for evaluating the material or coating for applications. [ABSTRACT FROM AUTHOR]

Light use efficiency characterizes the ability of a crop to convert radiation into biomass. Determining optimum cultivar-specific photosynthetic photon flux density (PPFD) values from sole-source lighting can be used to optimize leaf expansion, maximize biomass, and shorten the production period. This study evaluated the growth of hydroponic lettuce (Lactuca sativa) 'Rex' cultivated under different PPFD levels using sole-source lighting. At lower PPFD levels of 201 to 292 µmol·m−2·s−1, the plant projected canopy size (PCS) and specific leaf area increased to enhance light capture by 36.2% as compared to higher PPFD levels (333 and 413 µmol·m−2·s−1), while plants exhibited 10.3% lower canopy overlap ratio and 27.8% lower shoot dry weights. Both low and high PPFD conditions lead to a similar trend in PCS among plants. Light use efficiency was not a major factor in influencing lettuce growth. Instead, the critical factor was the total incident light the plants received. This study showcased the importance of incident light and PPFD on the growth, morphology, and biomass accumulation in lettuce. [ABSTRACT FROM AUTHOR]

Achyranthes japonica Nakai (AJN) is a medicinal plant known to be beneficial for the joints. Since it takes at least two years from sowing to harvesting in an open field, new AJN cultivation strategies are needed to shorten the production period and improve quality. In this study, high-quality AJN is produced as microgreens in a vertical farm using a commercial ginseng soil mix (Myeongpum-Insamsangto, Shinsung Mineral Co., Ltd., Goesan, Republic of Korea) and controlled environmental conditions. The cultivation conditions included a temperature of 23 ± 2 °C, relative humidity of 50 ± 10%, and a photosynthetic photon flux density of 170 ± 15 µmol·m−2·s−1. Pre-harvest intermittent UV-B exposure, with an intensity of 1.0 ± 0.3 W/m−2, was applied for one day before harvest to evaluate its effects, using controlled environmental conditions in the vertical farm. Ultraviolet-B (UV-B) irradiation increases secondary metabolite levels in plants; however, the effect of UV-B on 20-hydroxyecdysone (20E), an indicator of AJN, is unclear. Therefore, we aimed to investigate whether UV-B treatment of AJN microgreens affected growth and secondary metabolites. The treatment group was set to 12 h of continuous UV-B treatment during the day, two 6 h UV-B treatments, and four 3 h UV-B treatments to confirm the effectiveness of regular and intermittent treatment and recovery. Short-term UV-B treatment before harvesting increased phenols, flavonoids, antioxidant capacity, and 20E levels without affecting AJN biomass. The intermittent 6 h UV-B irradiation with a 6 h recovery time stimulated 20E content by approximately 1.4 times compared to the control. These study findings indicate that short-term UV-B treatment before harvesting, an appropriate recovery time, and intermittent UV-B exposure are more effective at increasing 20E content than continuous treatment. This approach provides a promising strategy for improving the nutritional and health benefits of AJN microgreens in vertical farming systems. [ABSTRACT FROM AUTHOR]

The X-ray column density ( N HX ) of gamma-ray bursts (GRBs) can probe the local environment of their progenitors over a wide redshift range. Previous work has suggested an increasing trend as a function of redshift. The relevance of this current analysis relies on investigating the selection bias method, such as the effect of the X-ray spectrum in high-redshift GRBs, which complicates the measurement of small N HX ; this has yet to be fully evaluated or discussed elsewhere. In this work, we evaluated these effects through simulations to define appropriate observational limits in the N HX versus redshift plane. We then applied a one-sided nonparametric method developed by Efron and Petrosian. Within the framework of this method, we investigated the redshift dependence of N HX and the local distribution function. Our results show that the evolution of N HX with redshift firmly exists with a significance of more than four sigma and follows a power law of (1 + z) 1.39 (+ 0.22 , − 0.27) . Based on these analyses and previous studies, the GRB progenitor mass varies but is more massive in the high-redshift environment and has a higher gas column density. This suggests that part of the luminosity evolution of GRBs, which has been widely reported, may be due to the evolution of the progenitor's mass. Using the same method, we demonstrate that optically dark GRBs show a consistent evolution: (1 + z) 1.15 (+ 0.67 , − 0.83) . By applying the Kolmogorov–Smirnov (KS) test, it is shown that optically dark GRBs have statistically identical flux and photon index distributions compared to normal GRBs, but the N HX is systematically larger. This result suggests that the darkness of some GRB populations is not due to an intrinsic mechanism, but rather because a higher density surrounds them. [ABSTRACT FROM AUTHOR]

Quantum metrology leverages quantum correlations for enhanced parameter estimation. Recently, structured light enabled increased resolution and sensitivity in quantum metrology systems. However, lossy and complex setups impacting photon flux hinder true quantum advantage while using high dimensional structured light. We introduce a straightforward mechanical rotation quantum sensing mechanism, employing high-dimensional structured light and use it with a high-flux (45 000 coincidence counts per second) N00N state source with N = 2. The system utilizes two opposite spiral phase plates with topological charge of up to ℓ = 16 that converts mechanical rotation into wavefront phase shifts and exhibit a 16-fold enhanced super-resolution and 25-fold enhanced sensitivity between different topological charges, while retaining the acquisition times, and with negligible change in coincidence count. Furthermore, the high efficiency together with the high photon flux enables detection of mechanical angular acceleration in real-time. Our approach paves the way for highly sensitive quantum measurements, applicable to various interferometric schemes. [ABSTRACT FROM AUTHOR]

In the last few decades, galactic stellar black hole X-ray binary systems (BHXRBs) have aroused intense observational and theoretical research efforts specifically focusing on their multi-messenger emissions (radio waves, X-rays, γ-rays, neutrinos, etc.). In this work, we investigate jet emissions of high-energy neutrinos and gamma-rays created through several hadronic and leptonic processes taking place within the jets. We pay special attention to the effect of the black hole’s spin (Kerr black holes) on the differential fluxes of photons originating from synchrotron emission and inverse Compton scattering and specifically on their absorption due to the accretion disk’s black-body radiation. The black hole’s spin (dimensionless spin parameter a*) enters into the calculations through the radius of the innermost circular orbit around the black hole, the RISCO parameter, assumed to be the inner radius of the accretion disk, which determines its optical depth τdisk. In our results, the differential photon fluxes after the absorption effect are depicted as a function of the photon energy in the range 1GeV ≤E≤103GeV. It is worth noting that when the black holes’ spin (α*) increases, the differential photon flux becomes significantly lower.

Beamline BL08U1A is a soft X-ray spectromicroscopy beamline at Shanghai Synchrotron Radiation Facility (SSRF) that exhibits the capabilities of high spatial resolution (30 nm) and high energy resolving power (over 104). As a first-generation beamline of SSRF, owing to its continuous operation over the last ten years, an urgent upgrade of the equipment including the monochromator was deemed necessary. The upgrade work included the overall construction of the monochromator and replacement of the mirrors upstream and downstream of the monochromator. Based on its original skeleton, two elliptically cylinder mirrors were designed to focus the beam horizontally, which can increase the flux density by about three times on the exit slits. Meanwhile, the application of variable-line-space gratings in the monochromator demonstrates the dual functions of dispersing and focusing on the exit slits which can decrease abberations dramatically. After the upgrade of the main components of the beamline, the energy range is 180–2000 eV, the energy resolving power reaches 16333 @ 244 eV and 12730 @ 401 eV, and the photon flux measured in the experimental station is over 2.45 × 109 photons s−1 (E/ΔE = 6440 @ 244 eV).

A spectroscopic setup for isomerization quantum yield determination is reported. The setup combines fiber-coupled LEDs, a commercially calibrated thermopile detector for measurement of the photon flux, and a fiber-coupled UV–vis spectrometer. By solving the rate equations numerically, isomerization quantum yields can be obtained from the UV–vis absorption spectra. We show that our results for the prototypical photoswitch azobenzene are in excellent agreement with the literature. The analysis of the errors showed that the quantum yields determined using this method are in the same order of magnitude as when using actinometry, thus demonstrating the reliability of our setup.

Smooth crabgrass [Digitaria ischaemum (Schreb.) Schreb. ex Muhl.] is one of the most troublesome summer annual weeds in cool‐season turfgrass. Field experiments demonstrated a strong relationship between spring photosynthetic active radiation reaching the soil surface and the resulting smooth crabgrass cover in Kentucky bluegrass (Poa pratensis L.) 2/3 months later in summer. Both smooth crabgrass and canopy penetrating light were consistently reduced by higher mowing heights. Follow‐up experiments in controlled environments were initiated to improve our understanding of how light quality and quantity influence smooth crabgrass germination and growth. Smooth crabgrass germination was ≥99% following exposure to blue, red (R), far red (FR), both R and FR light pulses, or complete darkness treatments. A second germination experiment examined six levels of turfgrass canopy shade (0%, 24%, 44%, 77%, 90%, and 100% photosynthetic photon flux density [PPFD] reduction) and found that smooth crabgrass germination was ≥99% for all treatments. These experiments indicate that light quality and quantity do not affect smooth crabgrass germination. A greenhouse experiment examined five levels of turfgrass canopy shade (0%, 44%, 59%, 81%, and 91% PPFD reduction). Smooth crabgrass quantum and PSII (Photosystem II) operating efficiency increased in response to shade, while leaf number and thickness, specific leaf weight, tillering, mass, electron transport rate, and stomatal conductance decreased with increasing shade. Overall, the results demonstrate that smooth crabgrass is able to germinate regardless of canopy density, but seedling growth, development, and plant function are diminished in a dense turfgrass canopy shade. [ABSTRACT FROM AUTHOR]

The biophysical characterization and engineering of optogenetic tools and photobiological systems has been hampered by the lack of efficient methods for spectral illumination of microplates for high-throughput analysis of action spectra. Current methods to determine action spectra only allow the sequential spectral illumination of individual wells. Here we present the open-source RainbowCap-system, which combines LEDs and optical filters in a standard 96-well microplate format for simultaneous and spectrally defined illumination. The RainbowCap provides equal photon flux for each wavelength, with the output of the LEDs narrowed by optical bandpass filters. We validated the RainbowCap for photoactivatable G protein-coupled receptors (opto-GPCRs) and enzymes for the control of intracellular downstream signaling. The simultaneous, spectrally defined illumination provides minimal interruption during time-series measurements, while resolving 10 nm differences in the action spectra of optogenetic proteins under identical experimental conditions. The RainbowCap is also suitable for studying the spectral dependence of light-regulated gene expression in bacteria, which requires illumination over several hours. In summary, the RainbowCap provides high-throughput spectral illumination of microplates, while its modular, customizable design allows easy adaptation to a wide range of optogenetic and photobiological applications. [ABSTRACT FROM AUTHOR]

To investigate the relationship between the lighting direction-induced morphophysiological traits and post-harvest storage of lettuce, the effects of different lighting directions (top, T; top + side, TS; top + bottom, TB; side + bottom, SB; and top + side + bottom, TSB; the light from different directions for a sum of light intensity of 600 μmol·m−2·s−1 photosynthetic photon flux density (PPFD)) on the growth morphology, root development, leaf thickness, stomatal density, chlorophyll concentration, photosynthesis, and chlorophyll fluorescence, as well as the content of nutrition such as carbohydrates and soluble proteins in lettuce were analyzed. Subsequently, the changes in water loss rate, membrane permeability (measured as relative conductivity and malondialdehyde (MDA) content), brittleness (assessed by both brittleness index and β-galactosidase (β-GAL) activity), and yellowing degree (evaluated based on chlorophyll content, and activities of chlorophyllase (CLH) and pheophytinase (PPH)) were investigated during the storage after harvest. The findings indicate that the TS treatment can effectively reduce shoot height, increase crown width, enhance leaves' length, width, number, and thickness, and improve chlorophyll fluorescence characteristics, photosynthetic capacity, and nutrient content in lettuce before harvest. Specifically, lettuce's leaf thickness and stomatal density showed a significant increase. Reasonable regulation of water loss in post-harvested lettuce is essential for delaying chlorophyll degradation. It was utilized to mitigate the increase in conductivity and hinder the accumulation of MDA in lettuce. The softening speed of leafy vegetables was delayed by effectively regulating the activity of the β-GAL. Chlorophyll degradation was alleviated by affecting CLH and PPH activities. This provides a theoretical basis for investigating the relationship between creating a favorable light environment and enhancing the post-harvest preservation of leafy vegetables, thus prolonging their post-harvest storage period through optimization of their morphophysiological phenotypes. [ABSTRACT FROM AUTHOR]

Evaluating different concentrations of oxygen on lettuce physiology, growth, and biochemical assays is pivotal for optimizing the nutrient film technique (NFT), boosting yields, and enhancing resource efficiency in sustainable greenhouse cultivation. Two lettuce varieties Lactuca sativa var. Lolo Bionta (Lugano) and Lolo Rosa (Carmesi), were grown using NFT in a greenhouse for two consecutive years during the months of December and January. A comparative methodology was adopted under a randomized complete block design (RCBD) to study plant growth under three different oxygen concentration levels: natural oxygen concentrations (NOC); elevated oxygen concentrations (EOC); and elevated oxygen concentrations under LED light (380–840 nm) (LED + EOC). The plants were exposed to EOC levels of 8.1–8.7 mg L−1 in December and 8.7–9.0 mg L−1 in January. Under LED + EOC conditions, the levels were 8.2–8.3 mg L−1 in December and 8.8–9.0 mg L−1 in January. The NOC levels were 6.8–7.1 mg L−1 in December and 7.2–7.8 mg L−1 in January for Lugano and Carmesi, respectively. The applied light intensity, measured as photosynthetic photon flux density (PPFD), ranged from 463 to 495 µmol m−2 s−1 for the Lugano and from 465 to 490 µmol m−2 s−1 for the Carmesi. The dissolved oxygen concentration and LED light exposure under greenhouse conditions had significant effects (p < 0.05) on the plant growth parameters. The biochemical and physiological attributes, including transpiration rate, stomatal conductance, nitrate, chlorophyll, sugar contents, net photosynthesis, and respiration rates, varied significantly across different oxygen concentrations. Data were analyzed using a two-way ANOVA with post hoc Tukey's HSD tests for significance (p < 0.05) using IBM SPSS Statistics (version 29.0.2.0). Both EOC and LED + EOC treatments significantly improved growth attributes compared to NOC in Lugano, with increases in plant height (16.04%, 0.85%), fresh mass (110.91%, 29.55%), root length (27.35%, 29.55%), and root mass (77.69%, 34.77%). For Carmesi, similar trends were observed with increases in plant height (5.64%, 13.27%), fresh mass (10.45%, 21.57%), root length (37.14%, 47.33%), and root mass (20.70%, 41.72%) under EOC and LED + EOC. In the intertreatment analysis, the effect of LED + EOC was more pronounced compared to EOC. In view of the intertreatment response, Lolo Bionta (Lugano) appeared to have a high overall horticultural performance (growth and yield in both EOC and LED + EOC compared to Lolo Rosa (Carmesi). The practical significance of these results lies in their potential to inform strategies for optimizing greenhouse environments, particularly through the manipulation of oxygen levels and light exposure. The significant increases in growth metrics, especially under the LED + EOC conditions, suggest that targeted environmental adjustments can lead to substantial improvements in lettuce yield and quality. The findings also contribute to the advancement of sustainable agricultural technologies aiming to enhance food security and sustainability. [ABSTRACT FROM AUTHOR]

The development of methods to detect plant stress is not only a scientific challenge, but is also of great importance for agriculture and forestry. However, at present, stress diagnostics based on plant spectral characteristics has several limitations: (1) the high dependence of stress assessment on plant species identity; (2) the poor differentiation of different types of stress; and (3) the difficulty of detecting stress before visible symptoms appear. In this regard, the development of plant spectral metrics represents a significant area of research. Ficus elastica plants were exposed under the photosynthetic photon flux density (PPFD) from 0 to 1200 μmol photons m−2s−1. Exposure of F. elastica leaves to excess light (EL) (≥400 μmol photons m−2s−1) resulted in an increase in reflectance in the yellow-green region (522–594 nm) and a decrease in reflectance in the red region (666–682 nm) of the spectrum, accompanied by a shift of the red edge point toward the longer wavelength. These changes were revealed using the previously proposed light stress index (LSI = mean(R666:682)/mean(R522:594)). Based on the results obtained, two new vegetation indices (VIs) were proposed: LSIRed = R674/R654 and LSINorm = (R674 − R654)/(R674 + R654), indicating light stress by changes in the red region of the spectrum. The results of the study showed that LSI, LSIRed, and LSINorm have a high degree of coupling strength with maximal quantum yields of photosystem II values. The plant response to EL exposure, as assessed by the values of these three VIs, was well expressed regardless of the PPFD levels. The effect of EL at non-stressful PPFDs (50–200 μmol photons m−2s−1) was found to disappear within one hour after cessation of exposure. In contrast, the effect of the stressful PPFD (800 μmol photons m−2s−1) was found to persist for at least 80 h after cessation of exposure. The results of the study indicate the need to consider light history in spectral monitoring of vegetation. [ABSTRACT FROM AUTHOR]

Multilayer gratings are increasingly popular optical elements at X‐ray beamlines, as they can provide much higher photon flux in the tender X‐ray range compared with traditional single‐layer coated gratings. While there are several proprietary software tools that provide the functionality to simulate the efficiencies of such gratings, until now the X‐ray community has lacked an open‐source alternative. Here MLgrating is presented, a program for simulating the efficiencies of both multilayer gratings and single‐layer coated gratings for X‐ray applications. MLgrating is benchmarked by comparing its output with that of other software tools and plans are discussed for how the program could be extended in the future. [ABSTRACT FROM AUTHOR]

Aerosol science is of utmost importance for both climate and public health research, and in recent years X‐ray techniques have proven effective tools for aerosol‐particle characterization. To date, such methods have often involved the study of particles collected onto a substrate, but a high photon flux may cause radiation damage to such deposited particles and volatile components can potentially react with the surrounding environment after sampling. These and many other factors make studies on collected aerosol particles challenging. Therefore, a new aerosol sample‐delivery system dedicated to X‐ray photoelectron spectroscopy studies of aerosol particles and gas molecules in‐flight has been developed at the MAX IV Laboratory. The aerosol particles are brought from atmospheric pressure to vacuum in a continuous flow, ensuring that the sample is constantly renewed, thus avoiding radiation damage, and allowing measurements on the true unsupported aerosol. At the same time, available gas molecules can be used for energy calibration and to study gas‐particle partitioning. The design features of the aerosol sample‐delivery system and important information on the operation procedures are described in detail here. Furthermore, to demonstrate the experimental range of the aerosol sample‐delivery system, results from aerosol particles of different shape, size and composition are presented, including inorganic atmospheric aerosols, secondary organic aerosols and engineered nanoparticles. [ABSTRACT FROM AUTHOR]

Beamline BL08U1A is a soft X‐ray spectromicroscopy beamline at Shanghai Synchrotron Radiation Facility (SSRF) that exhibits the capabilities of high spatial resolution (30 nm) and high energy resolving power (over 104). As a first‐generation beamline of SSRF, owing to its continuous operation over the last ten years, an urgent upgrade of the equipment including the monochromator was deemed necessary. The upgrade work included the overall construction of the monochromator and replacement of the mirrors upstream and downstream of the monochromator. Based on its original skeleton, two elliptically cylinder mirrors were designed to focus the beam horizontally, which can increase the flux density by about three times on the exit slits. Meanwhile, the application of variable‐line‐space gratings in the monochromator demonstrates the dual functions of dispersing and focusing on the exit slits which can decrease abberations dramatically. After the upgrade of the main components of the beamline, the energy range is 180–2000 eV, the energy resolving power reaches 16333 @ 244 eV and 12730 @ 401 eV, and the photon flux measured in the experimental station is over 2.45 × 109 photons s−1 (E/ΔE = 6440 @ 244 eV). [ABSTRACT FROM AUTHOR]

Here we present the new experimental stations devoted to the studies of matter under extreme conditions at the X-ray absorption beamlines BM23 and ID24-DCM that were recently refurbished within the ESRF – Extremely Brilliant Source (EBS) upgrade program. In comparison with the stations before the EBS upgrade, they exhibit outstanding performances in terms of sample positioning capabilities, acceptance of multi-detection systems and complex sample environments. In addition, significant improvements regarding the photon flux and focusing capabilities down to the submicron size have been achieved. These stations are now coupled with the new ESRF double crystal monochromators that exhibit an exceptional beam position and energy stability and that permit quick micro-EXAFS measurements down to one EXAFS/second, and hyperspectral EXAFS mapping. In this contribution, we discuss the choices regarding the sample and detector stages and illustrate the potential of the new setups for extreme conditions studies based on selected preliminary results. [ABSTRACT FROM AUTHOR]

Microgreens are vegetable greens that are harvested early while they are still immature and have just developed cotyledons. One of the disadvantages and a challenge in production is that they exhibit a short shelf life and may be damaged easily. In seeking to prolong the shelf life, some pre- and postharvest interventions have been investigated. Here, kale and mustard microgreens were grown in a controlled-environment walk-in chamber at +21/17 °C, with ~65% relative air humidity, while maintaining the spectral composition of deep red 61%, blue 20%, white 15%, and far red 4% (150, 200, and 250 µmol m−2 s−1 photosynthetic photon flux density (PPFD)). Both microgreens seemed to exhibit specific and species-dependent responses. Higher PPFD during growth and storage in light conditions resulted in increased contents of TPC in both microgreens on D5. Additionally, 150 and 250 PPFD irradiation affected the α-tocopherol content by increasing it during postharvest storage in kale. On D0 150 for kale and 200 PPFD for mustard microgreens, β-carotene content increased. D5 for kale showed insignificant differences, while mustard responded with the highest β-carotene content, under 150 PPFD. Our findings suggest that both microgreens show beneficial outcomes when stored in light compared to dark and that mild photostress is a promising tool for nutritional value improvement and shelf-life prolongation. [ABSTRACT FROM AUTHOR]

Agriculture in controlled environments has gained popularity over time. Compared to traditional agriculture, controlled environments emerge as an alternative to mitigate the negative impacts of conventional farming methods. However, controlled environment agriculture, particularly plant factories with artificial lighting, incurs higher electricity costs, primarily for supplemental lighting and dehumidification of the cultivation area. Given these high costs, it is crucial to understand how efficiently plants utilize available light to convert it into biomass. This understanding can be used to design lighting strategies to reduce electricity usage. In this study, we cultivated 'Rex' lettuce (Lactuca sativa) plants on a soilless substrate and used an ebb-and-flow system for irrigation and fertilization. Plants grew in varying photosynthetic photon flux density (PPFD) levels ranging from 125 to 375 µmol·m−2·s−1 and were assessed for various physiological responses. Our findings revealed that plants exposed to higher light levels exhibited greater final dry weight, increased photosynthetic activity, higher water use efficiency, and accelerated growth compared to those under lower light conditions. Notably, plants subjected to higher light intensities did not show a significant increase in transpiration, suggesting a potential trade-off between energy expenditure on supplemental lighting and dehumidification. This finding opens the possibility of reducing energy consumption for dehumidification and achieving economic savings by subjecting plants to optimal growing conditions for shorter durations. This depends on whether higher savings on dehumidification are achieved compared to the energy required to maintain high PPFD levels. [ABSTRACT FROM AUTHOR]

Time-resolved soft-x-ray-diffraction experiments give access to microscopic processes in a broad range of solid-state materials by probing ultrafast dynamics of ordering phenomena. While laboratory-based high-harmonic generation (HHG) light sources provide the required photon energies, their limited photon flux is distributed over a wide spectral range, rendering typical monochromatic diffraction schemes challenging. Here, we present a scheme for energy-dispersive soft-x-ray diffraction with femtosecond temporal resolution and photon energies across the water window from 200 to 600 eV. The experiment utilizes the broadband nature of the HHG emission to efficiently probe large slices in reciprocal space. As a proof-of-concept, we study the laser-induced structural dynamics of a Mo/Si superlattice in an ultrafast, non-resonant soft-x-ray diffraction experiment. We extract the underlying strain dynamics from the measured shift of its first order superlattice Bragg peak in reciprocal space at photon energies around 500 eV via soft-x-ray scattering simulations. [ABSTRACT FROM AUTHOR]

In the last few decades, galactic stellar black hole X-ray binary systems (BHXRBs) have aroused intense observational and theoretical research efforts specifically focusing on their multi-messenger emissions (radio waves, X-rays, γ -rays, neutrinos, etc.). In this work, we investigate jet emissions of high-energy neutrinos and gamma-rays created through several hadronic and leptonic processes taking place within the jets. We pay special attention to the effect of the black hole's spin (Kerr black holes) on the differential fluxes of photons originating from synchrotron emission and inverse Compton scattering and specifically on their absorption due to the accretion disk's black-body radiation. The black hole's spin (dimensionless spin parameter a * ) enters into the calculations through the radius of the innermost circular orbit around the black hole, the R I S C O parameter, assumed to be the inner radius of the accretion disk, which determines its optical depth τ d i s k . In our results, the differential photon fluxes after the absorption effect are depicted as a function of the photon energy in the range 1 GeV ≤ E ≤ 10 3 GeV. It is worth noting that when the black holes' spin ( α * ) increases, the differential photon flux becomes significantly lower. [ABSTRACT FROM AUTHOR]

Greenhouses are used to create the appropriate environment for plant growth. Controlling the level of lighting using shading nets is one of the most commonly used methods for making suitable environmental modifications in greenhouses. The objective of this study was to examine the impact of three colored shading nets (green, black, and beige at shading rates of 50%) on inside air temperature, relative humidity, and spectral distribution of light in a greenhouse, as well as their effect on the growth and yield of strawberry plants. Data were collected during winter (December and January) and spring (March and April) months from shaded and unshaded blocks. The green net had the highest transmittance to solar radiation (τSR) during the two periods (38% and 35%, respectively) and the highest transmittance to photosynthetically active radiation (τPAR) of 34% during spring months, while the beige net had the highest τPAR of 27% during winter months. The black net had the smallest τPAR values during the two periods (22% and 29%, respectively). The lowest total light levels per season for solar radiation (SR) and photosynthetically active radiation (PAR) (746.8 and 293.7 MJ·m−2, respectively) were obtained under the black net, compared with (906.7 and 320.8 MJ·m−2, respectively) for the beige net, and (969.6 and 337.2 MJ·m−2, respectively) for the green net. The ratio of PAR to SR (PAR:SR) was 41% and 44% outside and inside the greenhouse for the control (without shade), respectively. The black net had the highest ratio of PAR:SR (39%) among the treatment nets. The green net transmitted more light in the blue–green region (400 to 570 nm) and transmitted the highest photon flux at 480 nm, while the beige net increased the infrared radiation flux from 730 nm and above and transmitted the highest photon flux at 604 nm. The study found that the green net increased the ratio of blue to red light (B/R), while the beige and green nets reduced the red to far-red light (R/FR) ratio. The photosynthetic rate, conductance to water, and transpiration were significantly higher for strawberries grown under the beige net. These results indicate that the beige net positively influenced leaf and stem characteristics, leading to improved strawberry yields. The best yields of strawberries were obtained under the beige net and the control group (no shade), surpassing the yields achieved under the black net by 26.3% and 21.4%, respectively. [ABSTRACT FROM AUTHOR]

Silicon Photomultipliers (SiPMs) are single photon detectors that gained increasing interest in many applications as an alternative to photomultiplier tubes. In the field of space experiments, where volume, weight and power consumption are a major constraint, their advantages like compactness, ruggedness, and their potential to achieve high quantum efficiency from UV to NIR makes them ideal candidates for spaceborne, low photon flux detectors. During space missions however, SiPMs are usually exposed to high levels of radiation, both ionizing and non-ionizing, which can deteriorate the performance of these detectors over time. The goal of this work is to compare process and layout variation of SiPMs in terms of their radiation damage effects to identify the features that helps reduce the deterioration of the performance and develop the next generation of more radiation-tolerant detectors. To do this, we used protons and X-rays to irradiate several Near Ultraviolet High-Density (NUV-HD) SiPMs with small areas (single microcell, 0.2 × 0.2 mm2 and 1 × 1 mm2) produced at Fondazione Bruno Kessler (FBK), Italy. We performed online current-voltage measurements right after each irradiation step, and a complete functional characterization before and after irradiation. We observed that the main contribution to performance degradation in space applications comes from proton damage in the form of an increase in primary dark count rate (DCR) proportional to the proton fluence and a reduction in activation energy. In this context, small active area devices show a lower DCR before and after irradiation, and we propose light or charge-focusing mechanisms as future developments for high-sensitivity radiation-tolerant detectors. [ABSTRACT FROM AUTHOR]

In farming projects, environmental variations can affect growth, productivity, survival, and fertility, as well as the quality of the produced biomass. This is why estuarine algae could be a good alternative for developing aquaculture ventures in a global climate change scenario since they can develop in highly fluctuating environments with large temperature and salinity fluctuations and low light penetrability. In this study, the best culture conditions (i.e., temperature; nutrients with Provasoli culture medium (PES) and PES + Kelpak®, a commercial biostimulant based on algae; salinity and photon flux) for the growth and fertility of gametophytes and sporophytes of the estuarine alga Punctaria latifolia were evaluated. Gametophytes and sporophytes of P. latifolia showed good tolerance to a wide range of abiotic variables. Under culture conditions, both stages presented the highest growth at intermediate to high temperatures (16—20 °C) and intermediate to high salinity (27.5 – 35 psu). However, gametophytes grew better at intermediate to high nutrient concentrations of PES and PES + Kelpak® and low and high light intensity (5—35 µmol photons m−2 s−1), whereas sporophytes grew better at intermediate to low nutrients of PES and PES + Kelpak® and low light intensity (5 µmol photons m−2 s−1). Punctaria latifolia would be a potentially cultivable alternative due to its broad tolerance to unfavorable environmental conditions in the climatic change we face. [ABSTRACT FROM AUTHOR]

The neutron time-of-flight (nToF) diagnostic technique has a lengthy history in Inertial Confinement Fusion (ICF) and High Energy Density (HED) Science experiments. Its initial utility resulted from the simple relationship between the full width half maximum of the fusion peak signal in a distant detector and the burn averaged conditions of an ideal plasma producing the flux [Lehner and Pohl, Z. Phys. 207, 83–104 (1967)]. More recent precision measurements [Gatu-Johnson et al., Phys. Rev. E 94(8), 021202 (2016)] and theoretical studies [Munro, Nucl. Fusion 56, 035001 (2016)] have shown the spectrum to be more subtle and complicated, driving the desire for an absolute calibration of the spectrum to disambiguate plasma dynamics from the conditions producing thermonuclear reactions. In experiments where the neutron production history is not well measured, but the neutron signal is preceded by a concomitant flux of photons, the spectrum can be in situ calibrated using a set of collinear detectors to obtain a true "time-of-flight" measurement. This article presents the motivation and overview of this technique along with estimates of the experimental precision needed to make useful measurements in existing and future nToF systems such as the pulsed power Z-machine located in Albuquerque, NM, at Sandia National Laboratories. [ABSTRACT FROM AUTHOR]

The design of a vacuum ultraviolet spectroscopy system has been performed to monitor and provide feedback for impurity control in SPARC. The spectrometer, covering a wavelength range of 10–2000 Å through a flat-field configuration with diffraction gratings, incorporates five survey lines of sight. This allows for comprehensive impurity analysis across the core and four divertor regions (inner/outer and upper/lower). Its compact modular design facilitates vertical stacking of each spectrometer unit, significantly reducing space in the tokamak hall, where a dedicated radiation shielding bunker will be built. Safety features include a secondary helium enclosure to mitigate tritium permeation risks during deuterium–tritium (D–T) operations and shielding within the beamlines for enhanced radiation protection. The silicon carbide mirror design for divertor observation ensures its survivability in the in-vessel environment of SPARC, validated by thermal and electromagnetic analysis. Signal modeling and data acquisition testing results show that an exposure time of a few milliseconds is appropriate considering photon flux reaching the detector, demonstrating the system's capability for discharge control that includes disruption avoidance. [ABSTRACT FROM AUTHOR]

Adding far-red (FR, 700–800 nm) light to photosynthetic active radiation (400–700 nm) proved to be a possible approach to increasing plant biomass accumulation for lettuce production in indoor vertical farms with artificial lighting as a sole-source lighting. However, how FR light addition influences plant growth, development, and metabolic processes and the optimal value of FR photon flux density for greenhouse-grown lettuce under sunlight are still unclear. This work aims to quantify the value of supplementary FR light with different intensities on lettuce morphological and physiological characteristics in a greenhouse. Lettuce 'Dasusheng' (Lactuca sativa L.) was grown in a greenhouse under seven light treatments, including white plus red LEDs with FR photon flux density at 0, 10, 30, 50, 70, and 90 µmol m−2 s−1 (WR, WR + FR10, WR + FR30, WR + FR50, WR + FR70, and WR + FR90, respectively), and lettuce grown with sunlight only was marked as natural light (NL). FR light addition improved the electron transport flux per cross section and performance index (PIabs, PItotal) and decreased the changes in relative variable fluorescence of lettuce leaves compared to plants under NL. Specifically, the PIabs of lettuce leaves were 41%, 41%, 38%, 33%, 26%, and 25% lower under control than in plants under treatments WR + FR90, WR + FR70, WR + FR50, WR + FR30, WR + FR10, and WR, respectively. Leaf number, leaf area, and biomass accumulation of lettuce followed a quadratic function with increasing FR light intensity and were the highest under treatment WR + FR50. The shoot fresh weight and dry weight of lettuce were increased by 111% and 275%, respectively, under treatment WR + FR50 compared to NL. The contents of vitamin C, reducing sugar, total soluble sugar, and starch in lettuce showed a similar trend with biomass accumulation. In conclusion, with commonly used photosynthetic photon flux density (PPFD, 400–700 nm) around 200 μmol m−2 s−1, supplementary FR light intensity of 30~50 μmol m−2 s−1 was suggested to enhance the photochemistry efficiency, biomass accumulation, and carbohydrates' contents in greenhouse-grown lettuce. [ABSTRACT FROM AUTHOR]

Indoor production of basil (Ocimum basilicum L.) is influenced by light spectrum, photosynthetic photon flux density (PPFD), and the photoperiod. To investigate the effects of different lighting on growth, chlorophyll content, and secondary metabolism, basil plants were grown from seedlings to fully expanded plants in microcosm devices under different light conditions: (a) white light at 250 and 380 μmol·m−2·s−1 under 16/8 h light/dark and (b) white light at 380 μmol·m−2·s−1 under 16/8 and 24/0 h light/dark. A higher yield was recorded under 380 μmol·m−2·s−1 compared to 250 μmol·m−2·s−1 (fresh and dry biomasses 260.6 ± 11.3 g vs. 144.9 ± 14.6 g and 34.1 ± 2.6 g vs. 13.2 ± 1.4 g, respectively), but not under longer photoperiods. No differences in plant height and chlorophyll content index were recorded, regardless of the PPFD level and photoperiod length. Almost the same volatile organic compounds (VOCs) were detected under the different lighting treatments, belonging to terpenes, aldehydes, alcohols, esters, and ketones. Linalool, eucalyptol, and eugenol were the main VOCs regardless of the lighting conditions. The multivariate data analysis showed a sharp separation of non-volatile metabolites in apical and middle leaves, but this was not related to different PPFD levels. Higher levels of sesquiterpenes and monoterpenes were detected in plants grown under 250 μmol·m−2·s−1 and 380 μmol·m−2·s−1, respectively. A low separation of non-volatile metabolites based on the photoperiod length and VOC overexpression under longer photoperiods were also highlighted. [ABSTRACT FROM AUTHOR]

Based on Boolean logic, molecular keypad locks secure molecular information, typically with an optical output. Here we investigate a rare example of a molecular keypad lock with a chemical output. To this end, the light‐activated release of biologically important nitric oxide from a ruthenium complex is studied, using proton concentration and photon flux as inputs. In a pH‐dependent equilibrium, a nitritoruthenium(II) complex is turned into a nitrosylruthenium(II) complex, which releases nitric oxide under irradiation with visible light. The precise prediction of the output nitric oxide concentration as function of the pH and photon flux is achieved with an artificial intelligence approach, namely the adaptive neuro‐fuzzy inference system. In this manner an exceptionally high level of control over the output concentration is obtained. Moreover, the provided concept to lock a chemical output as well as the output prediction may be applied to other (photo)release schemes. [ABSTRACT FROM AUTHOR]

The BL17B beamline at the Shanghai Synchrotron Radiation Facility was first designed as a versatile high‐throughput protein crystallography beamline and one of five beamlines affiliated to the National Facility for Protein Science in Shanghai. It was officially opened to users in July 2015. As a bending magnet beamline, BL17B has the advantages of high photon flux, brightness, energy resolution and continuous adjustable energy between 5 and 23 keV. The experimental station excels in crystal screening and structure determination, providing cost‐effective routine experimental services to numerous users. Given the interdisciplinary and green energy research demands, BL17B beamline has undergone optimization, expanded its range of experimental methods and enhanced sample environments for a more user‐friendly testing mode. These methods include single‐crystal X‐ray diffraction, powder crystal X‐ray diffraction, wide‐angle X‐ray scattering, grazing‐incidence wide‐angle X‐ray scattering (GIWAXS), and fully scattered atom pair distribution function analysis, covering structure detection from crystalline to amorphous states. This paper primarily presents the performance of the BL17B beamline and the application of the GIWAXS methodology at the beamline in the field of perovskite materials. [ABSTRACT FROM AUTHOR]

Nanotomography with hard X‐rays is a widely used technique for high‐resolution imaging, providing insights into the structure and composition of various materials. In recent years, tomographic approaches based on simultaneous illuminations of the same sample region from different angles by multiple beams have been developed at micrometre image resolution. Transferring these techniques to the nanoscale is challenging due to the loss in photon flux by focusing the X‐ray beam. We present an approach for multi‐beam nanotomography using a dual‐beam Fresnel zone plate (dFZP) in a near‐field holography setup. The dFZP generates two nano‐focused beams that overlap in the sample plane, enabling the simultaneous acquisition of two projections from slightly different angles. This first proof‐of‐principle implementation of the dual‐beam setup allows for the efficient removal of ring artifacts and noise using machine‐learning approaches. The results open new possibilities for full‐field multi‐beam nanotomography and pave the way for future advancements in fast holotomography and artifact‐reduction techniques. [ABSTRACT FROM AUTHOR]

Temporal separation of red (R) and blue (B) (alternating R/B) photons has been reported to increase leaf area, photon capture, and yield of lettuce compared with delivering both colors together (concurrent R+B). We grew three diverse lettuce cultivars (Grand Rapids, Rex, and Red Sails) under concurrent R+B photons (9/1 ratio) and alternating R/B photons (9/1 ratio) under an equal daily light integral (DLI) of either 8.6 or 23 mol.m-2.d-1. Contrary to five previous studies, we found no increase in either leaf area or fresh mass and dry mass in any of the alternating R/B photon treatments compared with concurrent R+B photons. In fact, at a DLI at 8.6 mol.m-2.d-1, alternating R/B photons decreased the dry mass of 'Grand Rapids' and 'Rex' lettuce by 38% and 17%, respectively. Two previous studies reported that photosynthetic rates increased with alternating R/B photons; however, we found that the net assimilation rate was generally decreased by alternating R/B photons. An analysis of images obtained from automated digital photography revealed that the relative expansion rate of leaves was 61% higher during intervals of pure B rather than intervals of pure R photons at the same photosynthetic photon flux density; however, this did not result in a higher leaf area compared with concurrent R+B photons. Overall, our studies do not indicate that alternating R/B photons increase lettuce leaf area or yield compared with concurrent R+B photons. [ABSTRACT FROM AUTHOR]

Chirality plays a significant part in many vital processes, and to further our level of understanding, there is a steadily growing interest in enhancing the yield of enantioselective processes. Here, a multilayer with etched grooves is activated in a Kretschmann geometry and consists of alternating platinum Pt, silica SiO2, and silicon Si, as well as a silver Ag layer. Due to the production process, the groove surface exhibits a micrometric roughness, characterized by a typical vibrational mode at ω = 96 MHz. The mode is attributed to a localized acoustic vibration and has been detected as a transmitted signal. The outcomes of the inquiry include plasmonic amplification of the transmitted signal and its wavevector-less nature; in addition, it is shown that the signal is depolarized in reference to the incident beam because of the rough surface. When the Kretschmann scheme is combined with the depolarization brought on by the roughness, a built-in asymmetry results in a higher optical flux of spectrum photons in the depolarized plane than the co-polarized plane, resulting in distinct, enantioselective, and solely polarization-dependent spectral contrast. In conclusion, enantioselectivity is demonstrated for the D,L-penicillamine. [ABSTRACT FROM AUTHOR]