absorption

The Absorption Experience of Gen Y Beginning Teachers in Elementary Schools, From the Point of View of the Beginning Teachers and Their Mentors

Aim/Purpose . The present study aimed to understand in depth the experience of identity formation of beginning teachers (BTs), members of Gen Y, in their first year at elementary school, teaching students of Gen Alpha, from the perspective of BTs and their teacher mentors (TMs). Background. The purpose of the study was to compare the aspects described by BTs and their mentor teachers of the initial experience of teaching and of shaping the professional identity of BTs, members of Gen Y, in elementary schools, from the perspective of BTs and teacher mentors (TMs). Methodology. This was a qualitative study. Two groups participated in the study: (a) 75 BTs, members of Gen Y, and (b) 40 mentors of beginning teachers. Contribution. The findings of this study indicate that the creation of an emotionally and professionally supportive community led to a fruitful discussion on issues related to the process of absorption and integration of BTs in the school. This process advanced their professional development, expanding knowledge, abilities, strategies, and innovative pedagogical practices for classroom management, and meaningful teaching and learning in the classroom. The supportive community provided an emotional, professional, social-organizational, and evaluative-reflective response to the needs of BTs, facilitating meaningful interactions between the BTs and their students. It created for students a space for emotional training, organizing and managing behavior, regulating emotions and behavior, reducing feelings of anger, and arousing a feeling of optimism. Findings. The findings show that there was a conflict between the BTs’ and TMs’ perceptions of school reality. The mentors expected the BTs to adapt to the existing system, whereas the BTs perceived the process as one of formation of their identity as teachers. It turned out that parameters that were important to Gen Y teachers, such as knowing the school organization and being an influential factor that brings about change, were less important to their mentors. The findings of the present study reinforce those of previous studies that investigated the employment characteristics of Gen Y. Recommendations for Practitioners. A supportive community at school is likely to increase the level of mental well-being of Gen Y teachers. To this end, support communities of teachers by form and by discipline of study should be created. In the community, emphasis should be placed on reflection and mental resilience in all situations and challenging events that happen to the BTs to help them cope with the accumulated stress. Recommendations for Researchers. Students need a sensitive environment that is appropriate for Gen Alpha children. This environment must allow for emotional training and regulation, behavior organization and management to arouse a feeling of optimism and reduce anger. To develop students’ emotional, social, and cognitive abilities, teachers must teach with love, sensitivity, affectivity, and empathy. Impact on Society. To retain BTs and prevent them from quitting their career, schools must ensure that members of Gen Y understand the school organization and are satisfied with the way the organization is managed. They must have a sense of being significant partners in the life of the school. Under optimal working conditions, Gen Y teachers may greatly contribute to the values of education and equal opportunity, maximizing the personal potential of each student and the classroom as a whole, and making the school relevant. Future Research. Future studies should examine the characteristics of students belonging to Gen Alpha. One of the difficulties mentioned by BTs was a misunderstanding of the characteristics of Gen Alpha, which created problems in the interactions within the teaching staff and between the teachers and the students, and pre-vented gaining authority with other teachers and with students.




absorption

The Effects of Knowledge Sharing and Absorption on Organizational Innovation Performance – A Dynamic Capabilities Perspective




absorption

How Low-Temperature Absorption Chillers Can Optimize Food and Beverage Processing

As food and beverage manufacturers seek solutions to reduce operational costs and decarbonize, they may be surprised to find the answer in a solution that’s nearly a century old: absorption cooling.




absorption

Universal simulation of absorption effects for X-ray diffraction in reflection geometry

Analytical calculations of absorption corrections for X-ray powder diffraction experiments on non-ideal samples with surface roughness, porosity or absorption contrasts from multiple phases require complex mathematical models to represent their material distribution. In a computational approach to this problem, a practicable ray-tracing algorithm is formulated which is capable of simulating angle-dependent absorption corrections in reflection geometry for any given rasterized sample model. Single or multiphase systems with arbitrary surface roughness, porosity and spatial distribution of the phases in any combination can be modeled on a voxel grid by assigning respective values to each voxel. The absorption corrections are calculated by tracing the attenuation of X-rays along their individual paths via a modified shear-warp algorithm. The algorithm is presented in detail and the results of simulated absorption corrections on samples with various surface modulations are discussed in the context of published experimental results.




absorption

AnACor2.0: a GPU-accelerated open-source software package for analytical absorption corrections in X-ray crystallography

AnACor2.0 significantly accelerates the calculation of analytical absorption corrections in long-wavelength crystallography, achieving up to 175× speed improvements. This enhancement is achieved through innovative sampling techniques, bisection and gridding methods, and optimized CUDA implementations, ensuring efficient and accurate results.




absorption

AnACor2.0: a GPU-accelerated open-source software package for analytical absorption corrections in X-ray crystallography

Analytical absorption corrections are employed in scaling diffraction data for highly absorbing samples, such as those used in long-wavelength crystallography, where empirical corrections pose a challenge. AnACor2.0 is an accelerated software package developed to calculate analytical absorption corrections. It accomplishes this by ray-tracing the paths of diffracted X-rays through a voxelized 3D model of the sample. Due to the computationally intensive nature of ray-tracing, the calculation of analytical absorption corrections for a given sample can be time consuming. Three experimental datasets (insulin at λ = 3.10 Å, thermolysin at λ = 3.53 Å and thaumatin at λ = 4.13 Å) were processed to investigate the effectiveness of the accelerated methods in AnACor2.0. These methods demonstrated a maximum reduction in execution time of up to 175× compared with previous methods. As a result, the absorption factor calculation for the insulin dataset can now be completed in less than 10 s. These acceleration methods combine sampling, which evaluates subsets of crystal voxels, with modifications to standard ray-tracing. The bisection method is used to find path lengths, reducing the complexity from O(n) to O(log2 n). The gridding method involves calculating a regular grid of diffraction paths and using interpolation to find an absorption correction for a specific reflection. Additionally, optimized and specifically designed CUDA implementations for NVIDIA GPUs are utilized to enhance performance. Evaluation of these methods using simulated and real datasets demonstrates that systematic sampling of the 3D model provides consistently accurate results with minimal variance across different sampling ratios. The mean difference of absorption factors from the full calculation (without sampling) is at most 2%. Additionally, the anomalous peak heights of sulfur atoms in the Fourier map show a mean difference of only 1% compared with the full calculation. This research refines and accelerates the process of analytical absorption corrections, introducing innovative sampling and computational techniques that significantly enhance efficiency while maintaining accurate results.




absorption

Open-source electrochemical cell for in situ X-ray absorption spectroscopy in transmission and fluorescence modes

X-ray spectroscopy is a valuable technique for the study of many materials systems. Characterizing reactions in situ and operando can reveal complex reaction kinetics, which is crucial to understanding active site composition and reaction mechanisms. In this project, the design, fabrication and testing of an open-source and easy-to-fabricate electrochemical cell for in situ electrochemistry compatible with X-ray absorption spectroscopy in both transmission and fluorescence modes are accomplished via windows with large opening angles on both the upstream and downstream sides of the cell. Using a hobbyist computer numerical control machine and free 3D CAD software, anyone can make a reliable electrochemical cell using this design. Onion-like carbon nanoparticles, with a 1:3 iron-to-cobalt ratio, were drop-coated onto carbon paper for testing in situ X-ray absorption spectroscopy. Cyclic voltammetry of the carbon paper showed the expected behavior, with no increased ohmic drop, even in sandwiched cells. Chronoamperometry was used to apply 0.4 V versus reversible hydrogen electrode, with and without 15 min of oxygen purging to ensure that the electrochemical cell does not provide any artefacts due to gas purging. The XANES and EXAFS spectra showed no differences with and without oxygen, as expected at 0.4 V, without any artefacts due to gas purging. The development of this open-source electrochemical cell design allows for improved collection of in situ X-ray absorption spectroscopy data and enables researchers to perform both transmission and fluorescence simultaneously. It additionally addresses key practical considerations including gas purging, reduced ionic resistance and leak prevention.




absorption

A sub-100 nm thickness flat jet for extreme ultraviolet to soft X-ray absorption spectroscopy

Experimental characterization of the structural, electronic and dynamic properties of dilute systems in aqueous solvents, such as nanoparticles, molecules and proteins, are nowadays an open challenge. X-ray absorption spectroscopy (XAS) is probably one of the most established approaches to this aim as it is element-specific. However, typical dilute systems of interest are often composed of light elements that require extreme-ultraviolet to soft X-ray photons. In this spectral regime, water and other solvents are rather opaque, thus demanding radical reduction of the solvent volume and removal of the liquid to minimize background absorption. Here, we present an experimental endstation designed to operate a liquid flat jet of sub-micrometre thickness in a vacuum environment compatible with extreme ultraviolet/soft XAS measurements in transmission geometry. The apparatus developed can be easily connected to synchrotron and free-electron-laser user-facility beamlines dedicated to XAS experiments. The conditions for stable generation and control of the liquid flat jet are analyzed and discussed. Preliminary soft XAS measurements on some test solutions are shown.




absorption

Iterative Bragg peak removal on X-ray absorption spectra with automatic intensity correction

This study introduces a novel iterative Bragg peak removal with automatic intensity correction (IBR-AIC) methodology for X-ray absorption spectroscopy (XAS), specifically addressing the challenge of Bragg peak interference in the analysis of crystalline materials. The approach integrates experimental adjustments and sophisticated post-processing, including an iterative algorithm for robust calculation of the scaling factor of the absorption coefficients and efficient elimination of the Bragg peaks, a common obstacle in accurately interpreting XAS data, particularly in crystalline samples. The method was thoroughly evaluated on dilute catalysts and thin films, with fluorescence mode and large-angle rotation. The results underscore the technique's effectiveness, adaptability and substantial potential in improving the precision of XAS data analysis. While demonstrating significant promise, the method does have limitations related to signal-to-noise ratio sensitivity and the necessity for meticulous angle selection during experimentation. Overall, IBR-AIC represents a significant advancement in XAS, offering a pragmatic solution to Bragg peak contamination challenges, thereby expanding the applications of XAS in understanding complex materials under diverse experimental conditions.




absorption

Operando double-edge high-resolution X-ray absorption spectroscopy study of BiVO4 photoanodes

High energy resolution fluorescence detected X-ray absorption spectroscopy is a powerful method for probing the electronic structure of functional materials. The X-ray penetration depth and photon-in/photon-out nature of the method allow operando experiments to be performed, in particular in electrochemical cells. Here, operando high-resolution X-ray absorption measurements of a BiVO4 photoanode are reported, simultaneously probing the local electronic states of both cations. Small but significant variations of the spectral lineshapes induced by the applied potential were observed and an explanation in terms of the occupation of electronic states at or near the band edges is proposed.




absorption

VUV absorption spectra of water and nitrous oxide by a double-duty differentially pumped gas filter

The differentially pumped rare-gas filter at the end of the VUV beamline of the Swiss Light Source has been adapted to house a windowless absorption cell for gases. Absorption spectra can be recorded from 7 eV to up to 21 eV photon energies routinely, as shown by a new water and nitrous oxide absorption spectrum. By and large, the spectra agree with previously published ones both in terms of resonance energies and absorption cross sections, but that of N2O exhibits a small shift in the { ilde{f D}} band and tentative fine structures that have not yet been fully described. This setup will facilitate the measurement of absorption spectra in the VUV above the absorption edge of LiF and MgF2 windows. It will also allow us to carry out condensed-phase measurements on thin liquid sheets and solid films. Further development options are discussed, including the recording of temperature-dependent absorption spectra, a stationary gas cell for calibration measurements, and the improvement of the photon energy resolution.




absorption

Web-CONEXS: an inroad to theoretical X-ray absorption spectroscopy

Accurate analysis of the rich information contained within X-ray spectra usually calls for detailed electronic structure theory simulations. However, density functional theory (DFT), time-dependent DFT and many-body perturbation theory calculations increasingly require the use of advanced codes running on high-performance computing (HPC) facilities. Consequently, many researchers who would like to augment their experimental work with such simulations are hampered by the compounding of nontrivial knowledge requirements, specialist training and significant time investment. To this end, we present Web-CONEXS, an intuitive graphical web application for democratizing electronic structure theory simulations. Web-CONEXS generates and submits simulation workflows for theoretical X-ray absorption and X-ray emission spectroscopy to a remote computing cluster. In the present form, Web-CONEXS interfaces with three software packages: ORCA, FDMNES and Quantum ESPRESSO, and an extensive materials database courtesy of the Materials Project API. These software packages have been selected to model diverse materials and properties. Web-CONEXS has been conceived with the novice user in mind; job submission is limited to a subset of simulation parameters. This ensures that much of the simulation complexity is lifted and preliminary theoretical results are generated faster. Web-CONEXS can be leveraged to support beam time proposals and serve as a platform for preliminary analysis of experimental data.




absorption

RefXAS: an open access database of X-ray absorption spectra

Under DAPHNE4NFDI, the X-ray absorption spectroscopy (XAS) reference database, RefXAS, has been set up. For this purpose, we developed a method to enable users to submit a raw dataset, with its associated metadata, via a dedicated website for inclusion in the database. Implementation of the database includes an upload of metadata to the scientific catalogue and an upload of files via object storage, with automated query capabilities through a web server and visualization of the data and files. Based on the mode of measurements, quality criteria have been formulated for the automated check of any uploaded data. In the present work, the significant metadata fields for reusability, as well as reproducibility of results (FAIR data principles), are discussed. Quality criteria for the data uploaded to the database have been formulated and assessed. Moreover, the usability and interoperability of available XAS data/file formats have been explored. The first version of the RefXAS database prototype is presented, which features a human verification procedure, currently being tested with a new user interface designed specifically for curators; a user-friendly landing page; a full list of datasets; advanced search capabilities; a streamlined upload process; and, finally, a server-side automatic authentication and (meta-) data storage via MongoDB, PostgreSQL and (data-) files via relevant APIs.




absorption

The TR-icOS setup at the ESRF: time-resolved microsecond UV–Vis absorption spectroscopy on protein crystals

The technique of time-resolved macromolecular crystallography (TR-MX) has recently been rejuvenated at synchrotrons, resulting in the design of dedicated beamlines. Using pump–probe schemes, this should make the mechanistic study of photoactive proteins and other suitable systems possible with time resolutions down to microseconds. In order to identify relevant time delays, time-resolved spectroscopic experiments directly performed on protein crystals are often desirable. To this end, an instrument has been built at the icOS Lab (in crystallo Optical Spectroscopy Laboratory) at the European Synchrotron Radiation Facility using reflective focusing objectives with a tuneable nanosecond laser as a pump and a microsecond xenon flash lamp as a probe, called the TR-icOS (time-resolved icOS) setup. Using this instrument, pump–probe spectra can rapidly be recorded from single crystals with time delays ranging from a few microseconds to seconds and beyond. This can be repeated at various laser pulse energies to track the potential presence of artefacts arising from two-photon absorption, which amounts to a power titration of a photoreaction. This approach has been applied to monitor the rise and decay of the M state in the photocycle of crystallized bacteriorhodopsin and showed that the photocycle is increasingly altered with laser pulses of peak fluence greater than 100 mJ cm−2, providing experimental laser and delay parameters for a successful TR-MX experiment.




absorption

Nanostructure and dynamics of N-truncated copper amyloid-β peptides from advanced X-ray absorption fine structure

An X-ray absorption spectroscopy (XAS) electrochemical cell was used to collect high-quality XAS measurements of N-truncated Cu:amyloid-β (Cu:Aβ) samples under near-physiological conditions. N-truncated Cu:Aβ peptide complexes contribute to oxidative stress and neurotoxicity in Alzheimer's patients' brains. However, the redox properties of copper in different Aβ peptide sequences are inconsistent. Therefore, the geometry of binding sites for the copper binding in Aβ4–8/12/16 was determined using novel advanced extended X-ray absorption fine structure (EXAFS) analysis. This enables these peptides to perform redox cycles in a manner that might produce toxicity in human brains. Fluorescence XAS measurements were corrected for systematic errors including defective-pixel data, monochromator glitches and dispersion of pixel spectra. Experimental uncertainties at each data point were measured explicitly from the point-wise variance of corrected pixel measurements. The copper-binding environments of Aβ4–8/12/16 were precisely determined by fitting XAS measurements with propagated experimental uncertainties, advanced analysis and hypothesis testing, providing a mechanism to pursue many similarly complex questions in bioscience. The low-temperature XAS measurements here determine that CuII is bound to the first amino acids in the high-affinity amino-terminal copper and nickel (ATCUN) binding motif with an oxygen in a tetragonal pyramid geometry in the Aβ4–8/12/16 peptides. Room-temperature XAS electrochemical-cell measurements observe metal reduction in the Aβ4–16 peptide. Robust investigations of XAS provide structural details of CuII binding with a very different bis-His motif and a water oxygen in a quasi-tetrahedral geometry. Oxidized XAS measurements of Aβ4–12/16 imply that both CuII and CuIII are accommodated in an ATCUN-like binding site. Hypotheses for these CuI, CuII and CuIII geometries were proven and disproven using the novel data and statistical analysis including F tests. Structural parameters were determined with an accuracy some tenfold better than literature claims of past work. A new protocol was also developed using EXAFS data analysis for monitoring radiation damage. This gives a template for advanced analysis of complex biosystems.




absorption

Ray-tracing analytical absorption correction for X-ray crystallography based on tomographic reconstructions

Processing of single-crystal X-ray diffraction data from area detectors can be separated into two steps. First, raw intensities are obtained by integration of the diffraction images, and then data correction and reduction are performed to determine structure-factor amplitudes and their uncertainties. The second step considers the diffraction geometry, sample illumination, decay, absorption and other effects. While absorption is only a minor effect in standard macromolecular crystallography (MX), it can become the largest source of uncertainty for experiments performed at long wavelengths. Current software packages for MX typically employ empirical models to correct for the effects of absorption, with the corrections determined through the procedure of minimizing the differences in intensities between symmetry-equivalent reflections; these models are well suited to capturing smoothly varying experimental effects. However, for very long wavelengths, empirical methods become an unreliable approach to model strong absorption effects with high fidelity. This problem is particularly acute when data multiplicity is low. This paper presents an analytical absorption correction strategy (implemented in new software AnACor) based on a volumetric model of the sample derived from X-ray tomography. Individual path lengths through the different sample materials for all reflections are determined by a ray-tracing method. Several approaches for absorption corrections (spherical harmonics correction, analytical absorption correction and a combination of the two) are compared for two samples, the membrane protein OmpK36 GD, measured at a wavelength of λ = 3.54 Å, and chlorite dismutase, measured at λ = 4.13 Å. Data set statistics, the peak heights in the anomalous difference Fourier maps and the success of experimental phasing are used to compare the results from the different absorption correction approaches. The strategies using the new analytical absorption correction are shown to be superior to the standard spherical harmonics corrections. While the improvements are modest in the 3.54 Å data, the analytical absorption correction outperforms spherical harmonics in the longer-wavelength data (λ = 4.13 Å), which is also reflected in the reduced amount of data being required for successful experimental phasing.




absorption

The AUREX cell: a versatile operando electrochemical cell for studying catalytic materials using X-ray diffraction, total scattering and X-ray absorption spectroscopy under working conditions

Understanding the structure–property relationship in electrocatalysts under working conditions is crucial for the rational design of novel and improved catalytic materials. This paper presents the Aarhus University reactor for electrochemical studies using X-rays (AUREX) operando electrocatalytic flow cell, designed as an easy-to-use versatile setup with a minimal background contribution and a uniform flow field to limit concentration polarization and handle gas formation. The cell has been employed to measure operando total scattering, diffraction and absorption spectroscopy as well as simultaneous combinations thereof on a commercial silver electrocatalyst for proof of concept. This combination of operando techniques allows for monitoring of the short-, medium- and long-range structure under working conditions, including an applied potential, liquid electrolyte and local reaction environment. The structural transformations of the Ag electrocatalyst are monitored with non-negative matrix factorization, linear combination analysis, the Pearson correlation coefficient matrix, and refinements in both real and reciprocal space. Upon application of an oxidative potential in an Ar-saturated aqueous 0.1 M KHCO3/K2CO3 electrolyte, the face-centered cubic (f.c.c.) Ag gradually transforms first to a trigonal Ag2CO3 phase, followed by the formation of a monoclinic Ag2CO3 phase. A reducing potential immediately reverts the structure to the Ag (f.c.c.) phase. Following the electrochemical-reaction-induced phase transitions is of fundamental interest and necessary for understanding and improving the stability of electrocatalysts, and the operando cell proves a versatile setup for probing this. In addition, it is demonstrated that, when studying electrochemical reactions, a high energy or short exposure time is needed to circumvent beam-induced effects.




absorption

Study finds big increase in ocean carbon dioxide absorption along West Antarctic Peninsula

Full Text:

A new study shows that the West Antarctic Peninsula is experiencing some of the most rapid climate change on Earth, featuring dramatic increases in temperatures, retreats in glaciers and declines in sea ice. The Southern Ocean absorbs nearly half of the carbon dioxide -- the key greenhouse gas linked to climate change -- that is absorbed by all the world's oceans. The study tapped an unprecedented 25 years of oceanographic measurements in the Southern Ocean and highlights the need for more monitoring in the region. The research revealed that carbon dioxide absorption by surface waters off the West Antarctic Peninsula is linked to the stability of the upper ocean, along with the amount and type of algae present. A stable upper ocean provides algae with ideal growing conditions. During photosynthesis, algae remove carbon dioxide from the surface ocean, which in turn draws carbon dioxide out of the atmosphere. From 1993 to 2017, changes in sea ice dynamics off the West Antarctic Peninsula stabilized the upper ocean, resulting in greater algal concentrations and a shift in the mix of algal species. That's led to a nearly five-fold increase in carbon dioxide absorption during the summertime. The research also found a strong north-south difference in the trend of carbon dioxide absorption. The southern portion of the peninsula, which to date has been less impacted by climate change, experienced the most dramatic increase in carbon dioxide absorption, demonstrating the poleward progression of climate change in the region.

Image credit: Drew Spacht/The Ohio State University




absorption

How Low-Temperature Absorption Chillers Can Optimize Food and Beverage Processing

By splitting the absorption process into two steps, lithium bromide solution concentrations are lower in the system, enabling lower hot water temperatures within the generator, lower hot water flow rates, and the elimination of crystallization risk within the chiller.




absorption

pH-dependent pyridoxine transport by SLC19A2 and SLC19A3: Implications for absorption in acidic microclimates [Metabolism]

SLC19A2 and SLC19A3, also known as thiamine transporters (THTR) 1 and 2, respectively, transport the positively charged thiamine (vitamin B1) into cells to enable its efficient utilization. SLC19A2 and SLC19A3 are also known to transport structurally unrelated cationic drugs, such as metformin, but whether this charge selectivity extends to other molecules, such as pyridoxine (vitamin B6), is unknown. We tested this possibility using Madin-Darby canine kidney II (MDCKII) cells and human embryonic kidney 293 (HEK293) cells for transfection experiments, and also using Caco-2 cells as human intestinal epithelial model cells. The stable expression of SLC19A2 and SLC19A3 in MDCKII cells (as well as their transient expression in HEK293 cells) led to a significant induction in pyridoxine uptake at pH 5.5 compared with control cells. The induced uptake was pH-dependent, favoring acidic conditions over neutral to basic conditions, and protonophore-sensitive. It was saturable as a function of pyridoxine concentration, with an apparent Km of 37.8 and 18.5 μm, for SLC19A2 and SLC19A3, respectively, and inhibited by the pyridoxine analogs pyridoxal and pyridoxamine as well as thiamine. We also found that silencing the endogenous SLC19A3, but not SLC19A2, of Caco-2 cells with gene-specific siRNAs lead to a significant reduction in carrier-mediated pyridoxine uptake. These results show that SLC19A2 and SLC19A3 are capable of recognizing/transporting pyridoxine, favoring acidic conditions for operation, and suggest a possible role for these transporters in pyridoxine transport mainly in tissues with an acidic environment like the small intestine, which has an acidic surface microclimate.




absorption

Multifunctional core–shell CaSnO3@N-doped carbon coaxial nanocables with excellent lithium storage performance and efficient microwave absorption

Inorg. Chem. Front., 2024, Advance Article
DOI: 10.1039/D4QI02264E, Research Article
Xiaoqiang Li, Guangguang Guan, Siyi Tong, Xin Chen, Kaiyin Zhang, Jun Xiang
It is highly desirable but challenging to design multi-functional materials for energy storage and electromagnetic (EM) wave absorption.
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absorption

Effects of metal–metal bonding in photosensitizers: red-shifted absorption and oscillator strength enhancement

Inorg. Chem. Front., 2024, 11,7812-7821
DOI: 10.1039/D4QI02131B, Research Article
Oshan J. Jinarathne, Malkanthi K. Karunananda
Metal–metal bonds facilitate a red-shift in the maximum absorption wavelength and an enhancement of the oscillator strength in photosensitizers.
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absorption

Influence of symmetry breaking on the absorption spectrum of crystal violet: from isolated cations at 5 K to room temperature solutions

Phys. Chem. Chem. Phys., 2024, Advance Article
DOI: 10.1039/D4CP03825H, Paper
Open Access
  This article is licensed under a Creative Commons Attribution 3.0 Unported Licence.
Alexander Schäfer, Samuele Giannini, Dmitry Strelnikov, Theresa Mohr, Fabrizio Santoro, Javier Cerezo, Manfred M. Kappes
Theoretical and experimental spectroscopy of crystal violet resolves the influence of temperature and symmetry breaking on absorption properties in different environments.
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absorption

Quantitatively differentiating foliar adhesion and absorption of different lead-based particles on Solanum melongena L.

Environ. Sci.: Nano, 2024, 11,1417-1428
DOI: 10.1039/D3EN00640A, Paper
Bing Zhao, Siyu Zhang, Xuejiao Zhang, Qing Zhao, Jason C. White, Fengchang Wu, Baoshan Xing
This study quantitatively distinguished foliar adhesion and absorption between Pb nano- and submicron particles of different chemical forms.
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absorption

Self-absorption correction of NEXAFS spectra for intermediate sample thicknesses applied to organo-sulfur model compounds

J. Anal. At. Spectrom., 2024, 39,2893-2902
DOI: 10.1039/D4JA00232F, Paper
Open Access
  This article is licensed under a Creative Commons Attribution 3.0 Unported Licence.
Konstantin Skudler, Michael Walter, Michael Sommer, Matthias Müller
We present a self-absorption correction for NEXAFS which is valid for any sample thickness. The corrected spectrum is recovered in a forward calculation by fitting a model spectrum to experimental data of samples with ideally different thicknesses.
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absorption

Non-Hermitian metagrating for perfect absorption of elastic waves

Mater. Horiz., 2024, 11,1658-1667
DOI: 10.1039/D3MH01866K, Communication
Jiali Cheng, Yabin Hu, Bing Li
With only a specific small amount of loss, perfect absorption of elastic waves can be achieved by a compact NHMG composed of only a single type of unit cell, enabling cloaking for arbitrary-shaped targets.
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absorption

Rapid and green quantification of phloridzin and trilobatin in Lithocarpus litseifolius (Hance) Chun (sweet tea) using an online pressurized liquid extraction high-performance liquid chromatography at equal absorption wavelength method

Anal. Methods, 2024, Advance Article
DOI: 10.1039/D4AY00170B, Paper
Zhengming Qian, Qinggui Lei, Dan Tang, Guoying Tan, Qi Huang, Fucai Zhou, Wenhao Wang
Sweet tea is a functional herbal tea with anti-inflammatory, anti-diabetic, and other effects, in which phloridzin and trilobatin are two functional compounds.
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absorption

Association holds protest against delay in Anna University’s staff absorption, promotions




absorption

Probing Intersystem Crossing in Multi-brominated Eumelanin through Transient Absorption and Surface Hopping Dynamics

Org. Chem. Front., 2024, Accepted Manuscript
DOI: 10.1039/D4QO01832J, Research Article
Open Access
Kavya Vinod, Lukhmanul Hakeem K., Diana Thomas, Pallavi Panthakkal Das, Mahesh Hariharan
Achieving intersystem crossing (ISC) through structural tuning in biological systems is an evolving area for therapeutic and materials research. Eumelanin, a natural pigment, offers huge potential for bio-inspired material design,...
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absorption

Synthesis of supramolecular polymers with calix[4]arene and β-cyclodextrin and their application in heavy metal ion absorption

RSC Adv., 2024, 14,35697-35703
DOI: 10.1039/D4RA05559D, Paper
Open Access
Jian-Jian Bian, Shi-Jin Tang, Jiao Miao, Rui Lin, Guo-Li Huang, Ming-Yu Teng, Xiao-Mei Li
Two categories of supramolecular polymer monomers were produced by introducing the ureidopyrimidone quadruple-hydrogen bonding assemblies on the calix[4]arene and the β-cyclodextrin host units, which adsorbed up to 99% of Pb2+ and Cd2+.
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absorption

Microencapsulation of broccoli sulforaphane using whey and pea protein: in vitro dynamic gastrointestinal digestion and intestinal absorption by Caco-2-HT29-MTX-E12 cells

Food Funct., 2024, Advance Article
DOI: 10.1039/D4FO03446E, Paper
Open Access
  This article is licensed under a Creative Commons Attribution 3.0 Unported Licence.
Ali Ali Redha, Luciana Torquati, John R. Bows, Michael J. Gidley, Daniel Cozzolino
Sulforaphane-rich extract was prepared from broccoli. The extract was encapsulated with whey and pea protein isolates by freeze-drying. The products were characterised and assessed for in vitro bioaccessibility and bioavailability.
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absorption

Preparation and characterization of white shrimp hydrolysate-xylooligosaccharides Maillard products and their in vivo promotive effects of zinc absorption in mice

Food Funct., 2024, Accepted Manuscript
DOI: 10.1039/D4FO03709J, Paper
Shijie Dou, Xuening Yu, Yuewen Xu, Xiaoyang Liu, Fawen Yin, Deyang Li, Da-Yong Zhou
The Maillard reaction products, as a kind of glycosylation-based reaction, possess the metal-chelating ability. In this study, the white shrimp hydrolysate (WH) and xylooligosaccharides (XOS) were used to prepare the...
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absorption

Boosting Quantum Efficiency and Suppressing Self-Absorption in CdS Quantum Dots through Interface Engineering

Nanoscale, 2024, Accepted Manuscript
DOI: 10.1039/D4NR02990A, Paper
Shyamashis Das, Poulomi Mukherjee, Arpita Mukherjee, Anirban Dutta, Biswajit Bhattacharyya, Ashutosh Mohanty, Anshu Pandey, Priya Mahadevan, Ranjani Viswanatha, Dipankar D. Sarma
Applications of photoluminescence from semiconductor quantum dots (QDs) have faced the dichotomy of excitonic emission being susceptible to self-absorption and shallow defects reducing quantum yield (QY) catastrophically and doped emissions...
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absorption

Current progress and frontiers in three-dimensional macroporous carbon-based aerogels for electromagnetic wave absorption: a review

Nanoscale, 2024, Advance Article
DOI: 10.1039/D4NR03738C, Review Article
Han Ding, Bo Hu, Yu Wang, Yunchen Du
This article provides a timely review on the construction of three-dimensional macroporous carbon-based aerogels and their application in the field of electromagnetic absorption.
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absorption

Beyond Nanoparticle-based Oral Drug Delivery: Transporter-mediated Absorption and Disease Targeting

Biomater. Sci., 2024, Accepted Manuscript
DOI: 10.1039/D4BM00313F, Review Article
Open Access
  This article is licensed under a Creative Commons Attribution 3.0 Unported Licence.
Hana Cho, Kang Moo Huh, Hyun Ji Cho, Bogeon Kim, Min Suk Shim, Yong-Yeon Cho, Joo Young Lee, Hye Suk Lee, Young Jik Kwon, Han Chang Kang
Various strategies in the microscale/nanoscale have been developed to improve oral absorption of therapeutics. Among them, gastrointestinal (GI)-transporter/receptor-mediated nanosized drug delivery systems (NDDSs) have drawn attention due to their many...
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absorption

Quantification of the mixed-valence and intervalence charge transfer properties of a cofacial metal–organic framework via single crystal electronic absorption spectroscopy

Chem. Sci., 2020, Advance Article
DOI: 10.1039/D0SC01521K, Edge Article
Open Access
Patrick W. Doheny, Jack K. Clegg, Floriana Tuna, David Collison, Cameron J. Kepert, Deanna M. D'Alessandro
Gaining a fundamental understanding of charge transfer mechanisms in three-dimensional Metal–Organic Frameworks (MOFs) is crucial to the development of electroactive and conductive porous materials.
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absorption

X-ray absorption linear dichroism at the Ti K-edge of rutile (001) TiO2 single crystal

X-ray absorption linear dichroism of rutile TiO2 at the Ti K-edge provides information about the electronic states involved in the pre-edge transitions. Here, linear dichroism with high energy resolution is analyzed in combination with ab initio finite difference method calculations and spherical tensor analysis. It provides an assignment of the three pre-edge peaks beyond the octahedral crystal field splitting approximation and estimates the spatial extension of the corresponding final states. It is then discussed for the first time the X-ray absorption (XAS) of pentacoordinated titanium atoms due to oxygen vacancies and it is found that, similarly to anatase TiO2, rutile is expected to exhibit a transition on the low-energy side of peak A3. Its apparent absence in the experiment is related to the degree of p–d orbital mixing which is small in rutile due to its centrosymmetric point group. A recent XAS linear dichroism study on anatase TiO2 single crystals has shown that peak A2 has an intrinsic origin and is due to a quadrupolar transition to the 3d energy levels. In rutile, due to its centrosymmetric point group, the corresponding peak A2 has a small dipole moment explaining the weak transition. The results are confronted with recent picosecond X-ray absorption spectroscopy on rutile TiO2 nanoparticles.




absorption

Comparative study of the around-Fermi electronic structure of 5d metals and metal-oxides by means of high-resolution X-ray emission and absorption spectroscopies

The composition of occupied and unoccupied electronic states in the vicinity of Fermi energies is vital for all materials and relates to their physical, chemical and mechanical properties. This work demonstrates how the combination of resonant and non-resonant X-ray emission spectroscopies supplemented with theoretical modelling allows for quantitative analysis of electronic states in 5d transition metal and metal-oxide materials. Application of X-rays provides element selectivity that, in combination with the penetrating properties of hard X-rays, allows determination of the composition of electronic states under working conditions, i.e. non-vacuum environment. Tungsten metal and tungsten oxide are evaluated to show the capability to simultaneously assess composition of around-band-gap electronic states as well as the character and magnitude of the crystal field splitting.




absorption

Fluorescence-detected quick-scanning X-ray absorption spectroscopy

Time-resolved X-ray absorption spectroscopy (XAS) offers the possibility to monitor the state of materials during chemical reactions. While this technique has been established for transmission measurements for a number of years, XAS measurements in fluorescence mode are challenging because of limitations in signal collection as well as detectors. Nevertheless, measurements in fluorescence mode are often the only option to study complex materials containing heavy matrices or in samples where the element of interest is in low concentration. Here, it has been demonstrated that high-quality quick-scanning full extended X-ray absorption fine-structure data can be readily obtained with sub-second time resolution in fluorescence mode, even for highly diluted samples. It has also been demonstrated that in challenging samples, where transmission measurements are not feasible, quick fluorescence can yield significant insight in reaction kinetics. By studying the fast high-temperature oxidation of a reduced LaFe0.8Ni0.8O3 perovskite type, an example where the perovskite matrix elements prevent measurements in fluorescence, it is shown that it is now possible to follow the state of Ni in situ at a 3 s time resolution.




absorption

Saturation and self-absorption effects in the angle-dependent 2p3d resonant inelastic X-ray scattering spectra of Co3+

It is shown that the 2p3d resonant inelastic X-ray scattering intensity is distorted by saturation and self-absorption effects, i.e. by incident-energy-dependent saturation and by emission-energy-dependent self-absorption.




absorption

Study finds big increase in ocean carbon dioxide absorption along West Antarctic Peninsula

Full Text:

A new study shows that the West Antarctic Peninsula is experiencing some of the most rapid climate change on Earth, featuring dramatic increases in temperatures, retreats in glaciers and declines in sea ice. The Southern Ocean absorbs nearly half of the carbon dioxide -- the key greenhouse gas linked to climate change -- that is absorbed by all the world's oceans. The study tapped an unprecedented 25 years of oceanographic measurements in the Southern Ocean and highlights the need for more monitoring in the region. The research revealed that carbon dioxide absorption by surface waters off the West Antarctic Peninsula is linked to the stability of the upper ocean, along with the amount and type of algae present. A stable upper ocean provides algae with ideal growing conditions. During photosynthesis, algae remove carbon dioxide from the surface ocean, which in turn draws carbon dioxide out of the atmosphere. From 1993 to 2017, changes in sea ice dynamics off the West Antarctic Peninsula stabilized the upper ocean, resulting in greater algal concentrations and a shift in the mix of algal species. That's led to a nearly five-fold increase in carbon dioxide absorption during the summertime. The research also found a strong north-south difference in the trend of carbon dioxide absorption. The southern portion of the peninsula, which to date has been less impacted by climate change, experienced the most dramatic increase in carbon dioxide absorption, demonstrating the poleward progression of climate change in the region.

Image credit: Drew Spacht/The Ohio State University




absorption

Study finds big increase in ocean carbon dioxide absorption along West Antarctic Peninsula

Full Text:

A new study shows that the West Antarctic Peninsula is experiencing some of the most rapid climate change on Earth, featuring dramatic increases in temperatures, retreats in glaciers and declines in sea ice. The Southern Ocean absorbs nearly half of the carbon dioxide -- the key greenhouse gas linked to climate change -- that is absorbed by all the world's oceans. The study tapped an unprecedented 25 years of oceanographic measurements in the Southern Ocean and highlights the need for more monitoring in the region. The research revealed that carbon dioxide absorption by surface waters off the West Antarctic Peninsula is linked to the stability of the upper ocean, along with the amount and type of algae present. A stable upper ocean provides algae with ideal growing conditions. During photosynthesis, algae remove carbon dioxide from the surface ocean, which in turn draws carbon dioxide out of the atmosphere. From 1993 to 2017, changes in sea ice dynamics off the West Antarctic Peninsula stabilized the upper ocean, resulting in greater algal concentrations and a shift in the mix of algal species. That's led to a nearly five-fold increase in carbon dioxide absorption during the summertime. The research also found a strong north-south difference in the trend of carbon dioxide absorption. The southern portion of the peninsula, which to date has been less impacted by climate change, experienced the most dramatic increase in carbon dioxide absorption, demonstrating the poleward progression of climate change in the region.

Image credit: Drew Spacht/The Ohio State University




absorption

Light absorption anisotropic film, polarizing film, process for producing the polarizing film and display device using the polarizing film

A light absorption anisotropic film, wherein content of a liquid crystalline non-colorable low molecular weight compound is 30% by mass or less; and which is obtained by fixing the alignment of a dichroic dye composition comprising at least one type of azo-based dichroic dye having nematic liquid crystallinity; and shows a diffraction peak derived from a periodic structure in a direction parallel to the alignment axis on measurement of X-ray diffraction. The light absorption anisotropic film is high in dichroism.




absorption

Dichroic dye composition, light absorption anisotropic film, and polarizing element

A light absorption anisotropic film, having at least one dichroic dye, in which the light absorption anisotropic film shows a diffraction peak derived from a periodic structure in a direction in a plane of the light absorption anisotropic film in X-ray diffraction measurement and the diffraction peak has a half width of 1.0 Å or less.




absorption

Liquid-crystal compound, liquid-crystal composition, light absorption anisotropic film, and liquid-crystal display device

A liquid-crystal compound denoted by general formula (I) below wherein each of the groups is defined and Dye denotes an azo dye residue denoted by general formula (II) with X and n also being defined. The azo liquid-crystal compound is capable of orientation with a high degree of orientation order.




absorption

Sound absorption material and method of manufacturing sound absorption material

Described embodiments relate to a method of manufacturing a sound absorption material. The method comprises: forming a low density fibrous web to act as porous bulk absorber, the fibrous web containing a proportion of bi-components fibers, each bi-component fiber having a core material and a sheath material around the core material; applying a thin facing later to the low density fibrous web, wherein the facing layer is adhesively compatible with the sheath material; heating the fibrous web to a temperature sufficient to soften the sheath material of at least some of the bi-component fibers; and pressing the facing layer and fibrous web together under low pressure such that at least part of the facing layer contacts the softened sheath material of at least some of the bi-component fibers to form an adhesive bond between the facing layer and the fibrous web.




absorption

Aliphatic amine based nanocarbons for the absorption of carbon dioxide

A composition of matter, and method to make same, for a nano-based material including a nanocarbon support to which is attached an aliphatic amine. In particular, the composition of matter is an aliphatic amine-nanocarbon material that includes a nanocarbon (NC) support, such as C60, nano-graphite, graphene, nanocarbon ribbons, graphite intercalation compounds, graphite oxide, nano-coal, nanohorns, and combinations thereof, and further includes an aliphatic amine, such as polyethyleneimine (PEI).




absorption

Condenser cooling system and method including solar absorption chiller

A system configured to thermally regulate exhaust portions of a power plant system (e.g. steam turbine) is disclosed. In one embodiment, a system includes: a condenser adapted to connect to and thermally regulate exhaust portions of a steam turbine; and a cooling system operably connected to the condenser and adapted to supply a cooling fluid to the condenser, the cooling system including a solar absorption chiller adapted to adjust a temperature of the cooling fluid.




absorption

Solar-absorption hybrid modular cooling apparatus

The invention provides cooling apparatus comprising: a solar heat collection means (2); two or more absorption refrigeration modules (1), each module being arranged to receive heat from the heat collection means and to re-circulate refrigerant through an evaporator (16); and means for putting a fluid to be cooled into thermal contact with each of the evaporators.




absorption

Method for producing urea fertilizer with low moisture absorption tendencies

A method for producing urea granules having low moisture absorption capacity, with a urea granulator, having a granule flow inlet side and oppositely a granule flow outlet side, forming an axis alongside which granules from a urea solution and a urea/ammonium salt-stream are formed, whereby the solution and the salt-stream are sprayed as a mixture or separately via a feed system unit via various nozzles into the granulator onto a seed material. In this process the highest amount of the salt-stream is sprayed into the granulator at the granule flow inlet side and the amount of the salt-stream is decreased alongside the axis of the granulator from the granule flow inlet side to the granule flow outlet side.