Modular calibration board for automated calibration of hyperspectral cameras.

On the optimal spectral resolution in quadrupole central transition NMR at ultrahigh magnetic fields.

Balancing resolution, complexity, bandwidth, power, and scalability is essential for advancing single-point miniaturized spectrometers from lab prototypes to practical portable and integrated photonic systems. In this paper, we present a high-performance two-terminal asymmetric back-to-back organic spectrometer (BTBOS) that utilizes a bias-controlled multi-peak modulation strategy to mitigate the ill-posed inverse problem common in single-point architectures. The device achieves a 1nm spectral resolution across the broad 300-1000nm range, with a ∼0.25nm peak error and <2% spectral crosstalk, using only a low driving voltage of 0.6V. The device further features a structurally simple design along with remarkable stability and reproducibility. In addition, we demonstrate its practical applicability in spectral imaging. This scalable and energy-efficient approach paves the way for practical and commercial use of miniaturized spectrometers in wearable and on-chip optical systems.

Background: Nuclear Magnetic Resonance (NMR) spectroscopy is a powerful analytical tool in metabolomics, but it is often hindered by the high cost and technical complexity of the machines, limiting its clinical and point-of-care applications. Recent advances in benchtop NMR technology have sought to overcome these barriers by providing more compact, affordable, and user-friendly instruments. This systematic review aims to assess the potential of benchtop NMR in clinical metabolomics, highlighting its practical advantages, current applications, and technological challenges relative to high-field systems. Methods: For this systematic review we searched Web of Science and PubMed databases to identify studies employing benchtop NMR spectroscopy in clinical and biomedical applications. The review focuses on works that evaluated metabolic profiling in human and animal disease contexts, compared benchtop and high-field performance, and utilized advanced data analysis methods, including multivariate and machine learning approaches. Results: Among the 74 records identified, 15 research articles were eligible, including 11 studies involving human biospecimens and 4 studies concerning animal samples. The selected works were published between 2018 and 2025. These studies demonstrated the potential clinical utility of low-field NMR in differentiating disease states such as tuberculosis, type 2 diabetes, neonatal sepsis, and chronic kidney disease, achieving diagnostic accuracies comparable to high-field instruments. Conclusions: Although limited by lower sensitivity and spectral resolution, benchtop NMR represents a significant step toward the democratization of NMR-based metabolomics. Continued hardware development, improved pulse sequences, and the integration of artificial intelligence for spectral processing and modeling are expected to enhance its analytical power and accelerate its clinical adoption.

In-cell nuclear magnetic resonance (NMR) spectroscopy has emerged as a leading technique in structural biology, providing atomic-level insights into the structures, dynamics, and interactions of biomolecules within their native cellular environments. By bridging the gap between conventional in vitro studies and the complexity of living systems, in-cell NMR enables direct observation of biomolecular behavior under near-physiological conditions. This review highlights recent methodological advances that have expanded the scope and feasibility of in-cell NMR. Innovations in isotopic labeling, including selective incorporation strategies, have enhanced spectral resolution and sensitivity. Optimized delivery approaches, such as microinjection and electroporation, facilitate efficient introduction of labeled biomolecules into diverse cell types. The use of cryogenically cooled probes and high-field magnets further improves signal detection, enabling the study of low-abundance targets. We discuss key applications, including protein folding, conformational dynamics, biomolecular interaction networks, and nucleic acid structural rearrangements. In addition, in-cell NMR has proven invaluable for drug discovery, providing mechanistic insights into intracellular drug-target interactions. Despite these advances, challenges remain, including spectral overlap from endogenous components, low intracellular concentrations, and maintaining cell viability during extended experiments. Future developments integrating cryo-electron microscopy (cryo-EM), mass spectrometry (MS), hyperpolarization techniques, and advanced labeling strategies promise to enhance sensitivity, resolution, and applicability, solidifying in-cell NMR as an indispensable tool for probing biomolecular function in living cells.

Abstract. The world's most productive ecosystem, the mangrove forest, is a diverse collection of salt-tolerant plant communities in tropical and subtropical intertidal zones. They are found in tropical regions worldwide, with the Indo-Pacific area having the largest concentration. It ranges from 15 million hectares globally, with 123 nations and territories in tropical and subtropical regions, accounting for 1% of all tropical forests. Mangroves serve as a shoreline's natural barrier against ocean dynamics. However, due to human activities near the sea-sore area and other reasons, 35% of the world's mangrove forests were lost over the past two decades of the 20th century. Developers are increasingly targeting mangrove land due to urbanization. Consequently, mangrove afforestation and replanting have recently received much interest in lessening the effects of climate change. Conserving and restoring mangrove forests can lower the net CO2, stabilize coastlines, and reduce erosion. Governments and non-governmental groups have set high standards to enhance the world's mangrove area by 20% by 2030. Remote sensing-based analysis is used for these studies because of the extensive area monitoring, repeated observations, information collection beyond human vision, cost-effective solution, and change detection accessibility. It can also significantly save expenses and time for processes and labour requirements, but these techniques are complex. Global acquisition of a multispectral satellite of Sentinel-2 with high temporal, spectral, and spatial resolution is possible, providing an opportunity to monitor mangroves more consistently and regularly and using this satellite imagery. The study aims to identify, monitor, and recommend suitable sites to plant new mangroves. In this study, 90.58 km² of mangrove areas were identified, of which approximately 31 km² were found to be in good health. Additionally, 48 km² of land was classified as suitable for new mangrove plantations. These findings support informed data-driven conservation strategies, future restoration, and afforestation efforts.

Abstract Hierarchical mergers of galaxy clusters play a key role in converting gravitational energy into thermal and kinetic energy in the local Universe. Understanding this process requires the reconstruction of cluster merger geometry, with careful consideration of projection effects. With its unprecedented spectral resolution, XRISM enables the disentanglement of merging cluster components along the line of sight via X-rays for the first time. In this Letter, we focus on the massive cluster A1914, a puzzling case wherein the galaxy and dark matter (DM) distribution appear to be in tension with the X-ray morphology. We present XRISM observations of A1914 focusing on the velocity structure of the intracluster medium. The Resolve full-array spectrum requires two merging components along the line of sight, with bulk velocities offset by ∼1000 km s −1 and velocity dispersions of ∼200 km s −1 . The subarray maps of flux ratios, bulk velocity, and velocity dispersion show the two components are offset and overlapping in the plane of the sky, consistent with a major (mass ratio ∼3), near line-of-sight merger with a pericenter distance of ∼200 kpc. We conclude that the two subclusters create an overlapping spiral pattern, referred to as a “yin-yang” merger. This scenario is further supported by tailored hydrodynamical simulations of the A1914 merger, demonstrating that this type of merger can broadly reproduce the observed X-ray morphology, gas temperature map, gas velocity maps, DM distribution, and galaxy velocities. This work demonstrates the power of high-resolution X-ray spectroscopy, provided by XRISM, to resolve complex cluster merger geometries.

The excellent optoelectronic properties of perovskite quantum dots (PeQDs) have great potential in fields such as display, sensing, and encryption. However, the variable application scenarios present challenges to the range and accuracy of their spectral regulation. Here, a Brownian motion collision driven anion exchange strategy is proposed to achieve refined spectral regulation of PeQDs. By modulation of the ionic binding energy of halide particles and PeQDs and control of their collision intensity, the reaction rate and degree of anion exchange can be finely regulated. Consequently, the spectral resolutions of 0.392, 0.238, and 0.550 nm are achieved in the ranges of 470.4-480.2, 514.6-526.3, and 640.3-650.3 nm, respectively. The method can be used to fabricate filters for optical sensing chips. The photoresponse curves reached resolutions of 0.89, 1.15, and 1.39 nm within the ranges of 466.1-481.2, 536.0-553.2, and 677.3-698.1 nm, respectively, demonstrating the potential of this work in the field of spectral sensing.

The molecular dynamics of ionic liquids (ILs) can be probed using fast field cycling (FFC) NMR relaxometry. Conventionally, such studies focus on ILs where only one ionic species carries NMR-active nuclei or on systems combining H nuclei on the cations with F nuclei on the anions. This way, the dynamics of cations and anions can be resolved individually. However, the situation becomes considerably more complex in fully protonated systems where both ions contain protons, because the various relaxation pathways can no longer be disentangled. Here we report the first FFC NMR investigation of such a case, using the IL triethylammonium methanesulfonate ([TEA][OMs]). Our strategy exploits selective partial deuteration of the ionic species, which enables the separate evaluation of cation and anion dynamics. We demonstrate for the first time that, from the known partial relaxation rates together with the determined interionic distances and self-diffusion coefficients, the relaxation contribution arising from cation-anion interactions can be quantified. Remarkably, this approach even allows reconstruction of the total relaxation rate observed experimentally for the fully protonated IL. This methodology provides a fundamentally new route to overcoming the limited spectral resolution of FFC NMR relaxometry at low fields. More broadly, it establishes a framework for disentangling relaxation processes in complex multicomponent systems, thereby extending the applicability of FFC NMR to more challenging classes of ILs and related materials.

The goal of this study is to further the understanding of the wind formation mechanism in asymptotic giant branch (AGB) stars through the analysis of the close environment (within a few stellar radii) of the carbon star . X TrA X TrA was observed for the first time with the Mid-Infrared SpectroScopic Experiment instrument (MATISSE) in the L and N bands in low spectral resolution mode (R=30), and its close surroundings were mapped in specific wavelength ranges corresponding to specific molecules ( and HCN, at 3.1 and 3.8 μm) and dust (amorphous carbon and, for example, SiC at 11.3 μm), via image reconstruction techniques. The angular diameter of the star ranges from 10 mas in the L band pseudo-continuum (3.5 μm) to 20 mas at 3.1 and 11.3 μm. The reconstructed images show some mild elongated features (along the east-west direction) and asymmetric protrusions, which are most evident around 3.1 μm. Imaging results highlight the clumpy nature of the circumstellar environment, starting from the photospheric region up to more distant layers. The angular diameters found for X TrA in the image data are in agreement with previous photospheric diameter estimates (following VLTI/MIDI 8--13μm observations), and their wavelength dependence is similar to values found for other carbon stars observed with MATISSE ( and ). The 3.1 μm images presented here show highly asymmetric features, another case of a C-rich star with irregular morphologies close to the stellar disk; this supports the notion that the R Scl V Hya + HCN abundance distribution usually originates from a clumpy layer around carbon stars.

ABSTRACT This work presents a combination of cell‐node and cell‐centered compact finite difference scheme for the approximation of third derivatives involved in Korteweg–de Vries (KdV) equations. This approach employs a half‐shifted derivative construction at cell centers, avoiding the need for compact interpolation, thereby removing transfer errors; hence, it improves spectral resolution and maintains high‐order accuracy. Fourier analysis is performed to show the spectral properties of the proposed formulation, which provides higher spectral resolutions as compared to node‐based compact schemes. A filtering strategy is incorporated to suppress high‐frequency oscillations without compromising the accuracy of the numerical scheme, and the total variation diminishing Runge Kutta (TVDRK3) method is applied for time integration. Numerical experiments on linear, nonlinear, and coupled KdV systems are conducted, and a comparative analysis with cell‐node compact schemes confirms that the proposed scheme consistently reduces errors by up to an order of magnitude and achieves high spectral resolution properties.

Purpose. Comprehensive study of the effect of the activation process on the morphological, structural, and elemental characteristics of technical Carbon in order to create functional carbon-containing materials with specified properties. Methods. Surface morphology and dispersity were investigated by scanning electron microscopy (JEOL 6610LV, secondary electron detector, 20 kV, magnification up to ×100,000). Local elemental composition was determined by energy-dispersive X-ray analysis (Oxford Instruments) with element mapping. Confocal laser microscopy (OmegaScope AIST-NT, resolution up to 300 nm) was used to analyze particle shape, size, and aggregation. Crystallochemical analysis was carried out by the method of rethgenophase analysis of X-ray diffraction (EMMA, CuKα, λ = 1.5406 Å, 2θ range = 10 – 80°). Structural defects and functional groups were identified by the method of Raman scattering spectroscopy (laser λ = 532 nm, spectral resolution 3 cm -1 ). Results. It has been established that the activation process leads to a significant transformation of the technical Carbon structure. There is a decrease in the average particle size from ~3 μm for pyrolytic Carbon to ~2 μm for the activated form, accompanied by a decrease in the polydispersity coefficient from 1.2 to 0.3, which indicates a narrowing of the particle size distribution. The activation process ensures the uniform incorporation of silicon into the Carbon matrix, reaching a concentration of up to 3.2 at. %, resulting in the formation of a homogeneous Carbon-silica nanocompositestructure. At the same time, the Carbon component is structurally ordered, reaching the parameters characteristic of graphite with d 002 = 0.3354 nm. Conclusion. Activation of technical carbon allows for the purposeful formation of ordered Carbon-silica nanocomposites with a developed surface and controlled defectiveness, which are promising for use in sorption processes and catalysis.

Abstract We present the first high-resolution XRISM/Resolve view of the relativistically broadened Fe K line in Cygnus X-1. The data clearly separate the relativistic broad line from the underlying continuum and from narrow emission and absorption features in the Fe band. The unprecedented spectral resolution in the Fe K band clearly demonstrates that the flux excess can be attributed to a single, broad feature, as opposed to a superposition of previously unresolved narrow features. This broad feature can be best interpreted as emission consistent with an origin near the innermost stable circular orbit around a rapidly rotating black hole. By modeling the shape of the broad line, we find a black hole spin of a ≃ 0.98 and an inclination of the inner accretion disk of θ ≃ 63 ∘ . The spin is consistent with prior reflection studies, reaffirming the robustness of past spin measurements using the relativistic reflection method. The measured inclination provides reinforcing evidence of a disk-orbit misalignment in Cygnus X-1. These results highlight the unique abilities of XRISM in separating overlapping spectral features and providing constraints on the geometry of accretion in X-ray binaries.

Existing hyperspectral fusion computational imaging methods primarily rely on using high-resolution multispectral images (HRMSI) to provide spatial details for low-resolution hyperspectral images (LRHSI), thereby enabling the reconstruction of hyperspectral images. However, these methods are often limited by the low spectral resolution of the HRMSI, making the sampled tensors unable to provide effective information for the LRHSI in a finer spectral range. To achieve more accurate computational imaging results, we propose a Heterospectral Structure Compensation Sampling (HSC-sampling) mechanism. Unlike traditional spatial sampling methods, which directly calculate the interpolation between adjacent pixels, this mechanism analyzes the structural complementarity among different bands in LRHSI. It utilizes the information from other bands to compensate for the missing details in the current band. Additionally, a novel Multi-phase Mixed Modeling (M2M) approach is designed, expanding the model's analytical capabilities into multiple phases to accommodate the high-dimensional nature of HSI data. Specifically, it extracts fusion features from three phases and organizes the generated features along with the input features into a multi-variate mixed cube based on phase relationships, thereby capturing feature correlations across different phases. Based on the HSC-sampling mechanism and the M2M approach, we construct a Merging Residual Concatenation (MRC) hyperspectral fusion computational imaging network. Compared to other state-of-the-art methods, this network achieves significant improvements in fusion performance across multiple datasets. Moreover, the effectiveness of the HSC-sampling mechanism has been demonstrated in various hyperspectral imaging tasks. Code is available at: https://github.com/1318133/HSC-Sampling.

J-PAS (Javalambre Physics of the Accelerating Universe Astrophysical Survey) will present a groundbreaking photometric survey covering 8500 deg2$ of the visible sky from Javalambre, capturing data in 56 narrow-band filters. This survey promises to revolutionise galaxy evolution studies by observing ∼10^8 galaxies with low spectral resolution. A crucial aspect of this analysis involves predicting stellar population parameters from the observed galaxy photometry. In this study, we combined the exquisite J-PAS photometry with state-of-the-art single stellar population (SSP) libraries to accurately predict stellar age, metallicity, and dust attenuation with a neural network (NN) model. The NN was trained on synthetic J-PAS photometry from different SSP libraries (E-MILES, Charlot &amp; Bruzual, and XSL) to enhance the robustness of our predictions against individual SSP model variations and limitations. To create mock samples with varying observed magnitudes, we added artificial noise in the form of random Gaussian variations within typical observational uncertainties in each band. Our results indicate that the NN was able to accurately estimate stellar parameters for SSP models without any evident degeneracies, surpassing a Bayesian SED-fitting method on the same test set. We obtained the median bias, scatter, and the percentage of outliers: μ = (0.01 dex, 0.00 dex, 0.00 mag), σ_NMAD = (0.23 dex, 0.29 dex, 0.04 mag), f_o = (17%, 24%, 1%) at $ i ∼17 mag for the age, metallicity and dust attenuation, respectively. The accuracy of the predictions is highly dependent on the signal-to-noise ratio (S/N) of the photometry, achieving robust predictions up to i$ $∼ 20 mag.

Abstract. Remote sensing retrievals of atmospheric particle (i.e., aerosol) properties, such as those from lidars and polarimeters, are increasingly used to study aerosol effects on critical cloud and marine boundary layer processes. To ensure the reliability of these retrievals, it is important to validate them using aerosol measurements from in-situ instruments (i.e., external closure). However, achieving rigorous external closure is challenging because in-situ instruments often (1) provide dry (relative humidity (RH) &lt; 40 %) aerosol measurements, while remote sensors typically retrieve properties in ambient conditions and (2) only sample a limited aerosol size-range due to sampling inlet cutoffs. To address these challenges, we introduce the In-Situ Aerosol Retrieval Algorithm (ISARA), a methodological framework designed to enable closure between in-situ and remote sensing aerosol data by converting dry in-situ aerosol optical and microphysical properties into their humidified equivalents in ambient air. We apply ISARA to aerosol measurements collected during the NASA Aerosol Cloud meTeorology Interactions oVer the western ATlantic Experiment (ACTIVATE) field campaign to test its ability to generate aerosol properties that are physically consistent across in-situ and remote sensing platforms. To assess this performance, we conduct consistency analyses comparing ISARA-calculated intensive and extensive aerosol properties with corresponding measurements from (1) ACTIVATE's in-situ instruments (internal consistency), (2) Monte Carlo in-situ data simulations (synthetic consistency), (3) ACTIVATE's Second Generation High Spectral Resolution Lidar (HSRL-2) and Research Scanning Polarimeter (RSP) instruments (external consistency). This study demonstrates that: (1) appropriate a priori assumptions for aerosol can lead to consistency between many in-situ measurements and remote sensing retrievals in the ACTIVATE campaign, (2) ambient aerosol properties retrieved from dry in-situ and the RSP polarimetric data are compared showing reasonable agreement for the first time in literature, (3) measurements are externally consistent even in the presence of moderately absorbing (imaginary refractive index (IRI) &gt; 0.015) and coarse nonspherical particles, and (4) ISARA is likely limited by (i) under-sampling of low background concentrations (N &lt; 1 cm−3) for aerosol sizes greater than 5 µm in diameter as well as (ii) by an under-determined measurement system. These results suggest that additional in-situ measurements under ambient conditions, at a wider range of wavelengths, of the real refractive index, and of the coarse aerosol size distribution, can reduce the uncertainties of the in-situ ambient aerosol products. Although this study focuses on fine spherical aerosol mixtures with a coarse mode that is spherical or nonspherical (spheroidal), its success demonstrates that ISARA could have the potential to support systematic and physically consistent closure of aerosol data sets in various field campaigns and aerosol regimes.

A collective Thomson scattering (CTS) diagnostic system has been commissioned to measure the ion features of the jet plasma region of X-pinch plasma, including electron temperature, ion temperature, electron density, average charge state, and plasma bulk velocity. Due to the inherent nature of CTS, signals with two peaks within a very narrow wavelength range are observed, depending on the ion motion. To analyze CTS signals, a spectrometer with a high dispersion and high resolution is required. Accordingly, the spectrometer was designed and installed with a dispersion of 0.004 nm/pixel. Stray light at the laser wavelength (532 nm) must be carefully suppressed in an extremely narrow spectra range, while minimizing the spectral loss of the CTS signals. To achieve this, a volume Bragg grating narrow notch filter (optical density of 4) was installed at the entrance of the spectrometer. For the fine tuning of the optical alignment and for spectral calibration, the rotational Raman scattering spectrum was measured under atmospheric conditions (N2: 78%, O2: 21%). The spectral resolution, including instrumental broadening, was evaluated using a continuous wave laser with the wavelength of 532 nm transmitted through neutral density filters. The measured full width at half maximum is 0.0813 nm. The CTS signal from the jet region of the X-pinch plasma was successfully measured with the developed system. The theoretical CTS spectral density function, convolved with the spectral resolution, was compared with the measured CTS signal, and the characteristics of plasma jet were quantitatively analyzed.

Exploring the trade-offs between spatial and spectral resolution in mapping invasive alien trees

Raman spectroscopy is a non-invasive method to predict the total viable microbial count through the packaging material of vacuum packaged lamb meat.

Since 2010, the 40,m radio telescope of the Yebes Observatory has been devoted to very long baseline interferometry (VLBI) and single-dish observations. Up until 2019, it covered frequency bands between 2,GHz and 90,GHz in discontinuous and narrow radio windows that met the needs of the European VLBI Network (EVN) and the Global Millimeter VLBI Array (GMVA). The situation changed in 2019 when new receivers were built and installed at the telescope for the Q- (31.5--50,GHz) and W- (72--90.5,GHz) bands in the frame of the Nanocosmos1 project, a synergy project funded by the European Research Council. The 18.5,GHz instantaneous bandwidth is now fully covered in the two polarisations with 16 fast Fourier transform (FFT) spectrometers of 38,kHz resolution. This has allowed us to achieve an unprecedented level of ultra-sensitivity for line surveys, leading to the discovery of around 95 molecules in space over the last six years. These results have encouraged the construction of a new low-noise cryogenic receiver between 18,GHz and 32.3,GHz for the 40,m radio telescope with orthogonal polarisations (H &amp; V) and 19,kHz of spectral resolution. Due to the frequency resolution requirement and the limited number of FFT boards, the band has been split into two sub-bands for each polarisation: low-band (18--26,GHz) and high-band (26--32.3,GHz), with eight FFT spectrometers of 1,GHz instantaneous bandwidths per sub-band and per polarisation. Alternatively, the receiver can be configured to analyze the full receiver band (18--32.3,GHz) in a single polarisation (either H-pol or V-pol). Here, we present the characteristics of the receiver and the first astrophysical results demonstrating its performance. A detailed analysis of the radio frequency interferences (RFIs) generated by satellite down-link communications and its impact on spectroscopic studies of the interstellar and circumstellar media is also provided. In this context, we conclude that the radio astronomy community must continue to strive to protect the still RFI-free K/Ka radio windows from harmful radiocommunication signals.