Light Fraction Research Articles

STUDY OF THE EFFECT OF SUPERCRITICAL WATER ON SOLID PRODUCTS OBTAINED AFTER CRACKING

One of the possible applications of supercritical water is the conversion of heavy hydrocarbon feedstocks with a high content of resins and asphaltenes. The use of supercritical water makes it possible to reduce the yield of solid products and increase the yield of light fractions. In this work, a comparative analysis of the cracking processes of petroleum residue, asphaltenes and resins isolated from it was carried out in an environment of supercritical water and without water. The experiments were carried out in an autoclave at a temperature of 450 °С and a pressure of up to 47 MPa. Cracking duration – 60 min. Cracking of petroleum residue, as well as its individual components - resins and asphaltenes, in a supercritical water environment - showed a positive effect on conversion; in all experiments, the yield of solid products decreased and the yield of maltenes increased. Solid products were studied using X-ray diffraction and thermogravimetric analysis and scanning electron microscopy. Using X-ray diffraction analysis, the influence of supercritical water on the parameters of the macrostructure was studied. It was determined that cracking with water affects the increase in the distance between saturated fragments of molecules (dr) in the structure of solid cracking products in comparison with products obtained without water. Using scanning electron microscopy, the surface of particles of insoluble cracking products was characterized. Solid products obtained in a supercritical water environment have a porous surface. According to thermal analysis data, it is shown that solid products obtained by cracking in water are characterized by more intense dynamics of sample weight loss and a smaller residue at the final temperature. For citation: Nalgieva Kh.V., Kopytov M.A. Study of the effect of supercritical water on solid products obtained after cracking. ChemChemTech [Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol.]. 2024. V. 67. N 8. P. 113-120. DOI: 10.6060/ivkkt.20246708.14t.

Comparative Analysis of the Mineral Associations in the Sediments from Buor-Khaya Bay

According to the results of analysis of 99 samples of bottom sediments and submarine permafrost from wells 1D-14, 3D-14 and 1D-15 drilled in the Buor-Khaya Bay, differences in their mineral composition due to paleogeographic factors, namely Late Quaternary changes in climate and sea level, as well as regional hydrodynamics are shown. The basis of the light fraction of minerals was quartz and feldspar (mainly plagioclases), found in the form of grains of various dimensions and sorting degree, as well as fine grains. To a lesser extent, the presence of chlorites, kaolinite and serpentines is noted, illite and smectite are rare. 42 accessory minerals were identified in the heavy fraction (average yield 0.95%) concentrated in fine-grained sands. It mainly consists of pyroxenes, amphiboles, carbonatite, epidote, zoisite, magnetite, mica, garnet, limonite, sphene, leucoxene, ilmenite. Rutile, kyanite, sillimanite, zircon, tourmaline, apatite, and stavrolite were found in smaller quantities. In the studied strata, plant remnants and carbon-like particles (kerogen) are found, the contribution of which exceeds 5% by weight in a number of samples. The results of the study allowed to conclude that the basis of the petrofund of the studied deposits are most likely sedimentary rocks of the Kharaulakh ridge of the Verkhoyansk mountain system (sandstones, siltstones and mudstones). The presence of characteristic accessory minerals in the sediments marks the unloading of igneous and metamorphic rocks, but their contribution is subordinate. They probably also include rocks of the Verkhoyansk complex, common near the Tiksi.

Extraction of aromatic hydrocarbons from light petroleum fractions with lactam solvent

Extraction of aromatic hydrocarbons from light petroleum fractions with lactam solvent

Feasibility of fractional distillation of Eucalyptus hybrida essential oil for the separation of valuable compounds

Raw essential oil (EO) of Eucalyptus hybrida extracted from the leaves of trees found in Uttarakhand state and nearby areas consists of a mixture of monoterpenoids, sesquiterpenoids and several different volatile compounds of which 1,8-cineole i.e., eucalyptol, a monoterpenoid cyclic ether is a major component. The eucalyptol rich EO also holds antimicrobial, anti-inflammatory, broncholytic and mucolytic potential. In this work experimental tests were done to evaluate the feasibility of batch fractionation or fractional distillation (FD) technique in performing value addition of eucalyptus essential oil. The proximity of boiling points of eucalyptol, limonene and p-cymene act as a barrier in separating these compounds. A two-stage FD procedure was devised, which recovers relatively light terpene fractions in first stage and provides eucalyptol rich fractions in second stage. The GC-MS analysis of the fractionated samples revealed good separation results with three stage-B fractions (B8, B9 and B10) containing >90% purity of eucalyptol, while two stage-A fractions (A1 and A2) containing >90% purity of pinene mixture (α-pinene and β-pinene). FD thus proved to be an effective method for adding value to the eucalyptus EO.

ANALYSIS OF METHODS OF ETHANE PIPELINE TRANSPORTATION

The products of hydrocarbon light fractions processing are becoming of great demand. An important component of natural gas is ethane used for high-tech products at gas chemical complexes. Ethane production in situ is a promising direction, with its subsequent transportation to gas and chemical plants. The most economical type of transport is pipeline transportation, providing the construction of a pipeline system including facilities and a linear part. Ethane is a gas that can be transported along isothermal pipelines in both liquid and gaseous states. At the same time, the question of choosing the most rational variant is relevant. The article analyzes possible methods of transporting ethane and ethane fractions along pipelines, consideres variants for pumping gas in a liquid and gaseous states, taking into account the component composition of the product at a specified productivity and initial thermal parameters to summarize recommendations when choosing the most rational method of product transportation. A method is presented for the analytical representation of the dependences of pressure, elasticity, density and viscosity on temperature for the convenient determination of physical properties of multicomponent ethane fractions. The methodological foundations of the thermal and hydraulic analysis of variants for ethane transportation in two phase states – in liquid and gaseous – with the energy efficiency assessment of gas pumping are presented. It is shown that when transporting ethane in a gaseous state, the metal consumption for the pipeline increases twice as compared with the pipeline for transporting the product in a liquid state, while energy consumption also doubles.

A study of interacting galaxies from the Arp-Madore catalog. Triggering of star formation and nuclear activity

We present Gemini Multi-Object Spectrograph (GMOS) spectroscopic observations of 95 galaxies from the Arp Madore (1987) catalog of peculiar galaxies. These galaxies have been selected because they appear to be in pairs and small groups. These observations have enabled us to confirm that 60 galaxies are indeed interacting systems. For the confirmed interacting sample, we have built a matched control sample of isolated galaxies. We present an analysis of the stellar populations and nuclear activity in the interacting galaxies and compare them with the isolated galaxies. We find a median light (mass) fraction of 55<!PCT!> (10<!PCT!>) in the interacting galaxies coming from stellar populations younger than 2 Gyr and 28<!PCT!> (3<!PCT!>) in the case of the isolated galaxies. More than half of the interacting galaxies are dominated by this young stellar population, while in the isolated ones most of the light comes from older stellar populations. We used a combination of diagnostic diagrams (BPTs and WHAN) to classify the main ionization mechanisms of the gas. The interacting galaxies in our sample consistently show a higher fraction of active galactic nuclei (AGN) relative to the control sample, which ranges between 1.6 and 4 depending on the combination of diagnostic diagrams employed to classify the galaxies and the number of galaxies considered. Our study provides further observational evidence that interactions drive star formation and nuclear activity in galaxies and can have a significant impact on galaxy evolution.

Sole-source Lighting of Lettuce that Increased Yield Had No Negative Effect on Postharvest Longevity

The effects of sole-source lighting on the growth and yield of hydroponically grown lettuce have been extensively studied, but research of postharvest performance is limited. We grew frill-leaf lettuce (Lactuca sativa) ‘Green Incised’ and ‘Hydroponic Green Sweet Crisp’ hydroponically in an indoor vertical research farm under daily light integrals (DLIs) of 12 or 18 mol⋅m−2⋅d−1 and the following three ratios of blue (B; 400–499 nm) and red (R; 600–699 nm) light from light-emitting diode fixtures: B5:R95, B20:R80, and B35:R65. We postulated that biomass accumulation would increase with the DLI and decrease with the B light fraction, and that postharvest longevity would increase with the DLI and the B light fraction. As expected, shoot fresh weight, leaf length and width, leaf number, and relative chlorophyll content (SPAD; ‘Green Incised’ only) decreased as the proportion of B light increased from 5% to 35%. Decreasing the DLI from 18 to 12 mol⋅m−2⋅d−1 reduced the shoot fresh weight and leaf number of both cultivars. Leaves of ‘Green Incised’ were up to 27% wider under B5:R95 and 60% longer under B5:R95 at 12 mol⋅m−2⋅d−1 than those under treatments with a higher DLI or more B light. The shoot fresh weight of ‘Hydroponic Green Sweet Crisp’ was greatest when grown under B5:R95 at 18 mol⋅m−2⋅d−1 and decreased as B light increased or DLI decreased. At the time of harvest, leaves of each cultivar and treatment were placed in clamshells and stored at 7 °C in darkness and evaluated for decay. ‘Green Incised’ that grew under B35:R65 and a DLI of 18 mol⋅m−2⋅d−1 had the shortest storage life, with 9.5 d and 11.4 d for replications 1 and 2, respectively, which were ∼2.5 to 4.0 d and 1.4 to 3.6 d earlier, respectively, than the storage life of lettuce grown under other treatments. In contrast, ‘Hydroponic Green Sweet Crisp’ was not influenced by light quality or DLI and had a storage life of 12.6 to 13.3 d and 13.5 to 14.3 d for replications 1 and 2, respectively. Therefore, a B light fraction between 5% and 20% and a DLI of 18 mol⋅m−2⋅d−1 produced high-yielding frill-leaf lettuce with a relatively long storage life.

OPTIMIZATION OF THE OPERATION OF AN ISOMERIZATION INSTALLATION FOR LIGHT PETROL FRACTIONS

The interest in this process lies in the fact that it has great value since low-octane components are used as raw materials - the n fraction. temperature – 62°С and catalytic reforming raffinates. This raw material contains mainly pentane and hexane fractions. This raw material, as well as fractions С5 and С6 obtained from a gas fractionation unit (GFU), and a central gas fractionation unit (CGFU), are isomerized in a hydrogen environment in the presence of a catalyst. Hydrocarbons with a relatively high octane number are obtained. When isomerizing the pentane fraction, a product with a higher octane number is obtained. Isomerization of n-pentane is of interest not only for the oil refining industry, but also for the petrochemical industry, since isopentane can be converted by dehydrogenation into isoprene, a raw material for rubber. The article conducted a study on the selection of the optimal catalyst for the light gasoline fraction isomerization unit located at the Atyrau Oil Refinery. The catalytic activity of the catalyst samples was assessed in a laboratory flow-type installation. Determination of the mass fraction of С2-С5 hydrocarbons in С5 hydrocarbon fractions (in raw materials and catalyst) was carried out by a method based on the separation of mixture components by gas-liquid chromatography. The components leaving the chromatographic column were detected using a thermal conductivity detector. The calculation of the mass fractions of components was carried out using the normalization method, taking into account correction factors. The minimum concentration of C2-С5 hydrocarbons, determined by the method used, is 0.01-0.05% wt.

Utilization of waste tires in the process of thermal cracking of vacuum gas oil

The process of thermal cracking of vacuum gas oil (VGO) with the addition of 10% tire crumb at a temperature of 500 °C and feed rate of 1 h- ¹ was studied. In the course of the study experiments were carried out, which showed that the introduction of tire crumb into the composition of VG promotes the acceleration of conversion of the heavy fraction of VG. Addition of 10% of tire crumb has a positive effect on the cracking process, which is expressed in the increase in the yield of diesel fraction by weight by 2%. Analysis of the material balance of the thermal cracking process of crushed tire crumb shows that under these conditions tire crumb was poorly subjected to thermal transformation. The yield of gasoline fraction and light gas oil fraction in the catalyst composition was only 1% and 7.4% by weight, respectively. The conversion of tire crumb into light fractions including gas oil reached 20.5%. Addition of 10% by weight of tire crumb to the composition of vacuum gas oil increases the yield of gasoline and diesel fractions (light gas oil fractions), while reducing the amount of heavy gas oil. The increase in the yield of diesel fraction is 4% by weight, and the total conversion of blended feedstock reaches 59.5%. Thus, the addition of tire crumb to the composition of vacuum gas oil practically does not affect the total conversion, but increases the yield of light gas oil. This allows us to conclude that the introduction of tire crumb contributes to a more efficient conversion of heavy fractions of vacuum gas oil. After hydrotreating process the obtained diesel and gasoline fractions can be successfully used as components of automotive fuels. Thus, the addition of tire crumb to the thermal cracking process of vacuum gas oil not only improves the conversion of heavy fractions, but also increases the yield of valuable products such as diesel fuel, which is important for the refining industry.

Catalytic upgrading of Naomaohu coal pyrolysis volatiles over CaO catalyst

Catalytic upgrading of coal pyrolysis volatiles is one the promising way to achieve high quality tar and gas. In this study, catalytic upgrading of volatiles from Naomaohu (NMH) coal pyrolysis has been conducted in a two-stage fixed bed reactor using CaO as catalyst. The aim of this work was to investigate the catalytic effect of CaO on the gas and liquid product distribution, as well as the variations in gas and coal tar components. Simulated distillation and GC-MS analysis has been used to understand the distribution of tar component. On the one hand, CaO exhibits selective cleavage of large molecules, such as long-chain esters, leading to the production of aromatics through the processes of dehydrocyclization and aromatization. CaO has the ability to stabilize free radicals that are generated during the cleavage of large molecules, thereby promoting the formation of light aromatic hydrocarbons. Consequently, the light tar fraction (boiling point <360 °C) increased from 64.4 % to 74.6 %, while the heavy tar fraction (boiling point＞360 °C) decreased from 35.6 % to 25.4 % in the pyrolysis tar. The compounds with long ester chains in the tar composition decreased by 24.4 %. The content of light components, such as benzenes, naphthalene, and phenols, increased significantly with the increasing catalytic temperature. Specifically, the content of benzenes, naphthalene, and phenols increased by 11.83 %, 17.73 %, and 4.41 % respectively at the coal to CaO ratio of 1/0.5 and the catalytic temperature of 600 °C. On the other hand, the CaO absorbs the CO2 pyrolysis gas leading to an elevation in the concentration of CH4 and H2 in the pyrolysis gas. The concentration of CO2 decreased from 37.9 % to 16.58 % compared to without the catalyst while the concentrations of H2 and CH4 increased to 26.24 % and 31.15 % at the catalytic temperature of 450 °C. The CO2 absorption ratio reached a maximum value of 97.16 % at a coal to CaO ratio of 1/2. These findings suggest that the CaO catalyst beneficial both for improving the tar and gas quality.

Supercritical water upgrading of heavy oil: Effects of reservoir minerals on pyrolysis product distribution

Supercritical water upgrading (SCWU) is a promising technology for heavy oil recovery and refining, in which minerals could act as catalysts, but the effect on the upgraded product distribution remains unclear. In this study, heavy oil upgrading experiments in supercritical water (SCW) were carried out at 400°C and 25 MPa to investigate the effects of reservoir minerals such as quartz, carbonate, feldspar and clay minerals on the upgrading process. The result indicated that carbonate minerals and clay-bearing minerals produced noticeable benefits to the SCWU of heavy oil process. In carbonate minerals, dolomite showed the strongest catalytic effect in promoting hydrothermal cracking of hydrocarbon macromolecules, with a 5.6 % reduction in heavy fraction and a 12.2 % increase in light fraction of the upgraded oil. Clay-bearing minerals mainly exhibited oil-enhancing and coking-inhibiting benefits, calcium montmorillonite exhibited the most significant increase in oil production of 9 %, while zeolite most significantly reduced the coke activation energy by 62 %. Regarding the catalytic mechanism, the catalytic effect of carbonates originated from the MgO and CaO sites on the surface. For clay minerals, the acidic catalytic sites exist in the interlayer domains of montmorillonite and in the pores of zeolite provided higher catalytic efficiencies in oil production. This study demonstrated the feasibility of using natural minerals as inexpensive catalysts for supercritical water upgrading of heavy oil.

Ex-situ and in-situ catalytic pyrolysis of Naomaohu coal with red mud-modified char and red mud leaching solution

Pyrolysis is an enabling technology to extend the value chain of coal while reducing its emissions. To improve the product distribution of coal pyrolysis at a reasonable cost, this work explored the utilization of industrial waste-derived red mud modified char (RMMC) and red mud leaching solution (RMLS) for ex-situ and in-situ catalytic coal pyrolysis, respectively. The structural and compositional features of RMMC catalyst and RMLS-loaded coals were revealed by XRD, physisorption, FT-IR, XPS, and Raman spectroscopy. The pyrolysis experiments with RMMC and RMLS were conducted in a two-stage fixed bed reactor and a one-stage fixed bed reactor, respectively. As compared to non-catalytic pyrolysis, RMMC increased the light tar fraction by 28.3 %, dropped the heavy tar yield from 4.4 wt% to 2.0 wt%, and reduced the contents of heteroatoms (O/N/S) in tar significantly at 500 °C. With 0.25 wt% RMLS, the light tar fraction was increased by 21.7 %, and the heavy tar yield was lowered to 2.8 wt%. This work demonstrated the feasibility and potential of RMMC and RMLS-catalyzed coal pyrolysis to empower both coal and aluminum industries.

Effects of Warming and No-Tillage on Soil Carbon, Nitrogen, Phosphorus and Potassium Contents and pH of an Alpine Farmland in Tibet

There are still great uncertainties about effects of climate warming and no-tillage on soil carbon, nitrogen, phosphorus and potassium contents and pH in alpine farmlands. A warming (control; daytime warming, DW; nighttime warming, NW; all-day warming, DW + NW) and no-tillage (no-tillage vs. tillage) experiment was conducted in an alpine farmland of the Lhasa, Xizang since 2015. Soil organic carbon, total nitrogen, total phosphorus, total potassium (TK), available nitrogen, available phosphorus, available potassium, dissolved organic carbon (DOC), active organic carbon, particulate organic carbon (POC), light fraction organic carbon, and heavy fraction organic carbon contents and pH at four depths (0–5, 5–15, 15–25, and 25–35 cm) were measured. Warming effects on concerned soil variables differed with warming time, soil depth, and no-tillage. No-tillage effects on concerned soil variables differed with warming-time (daytime, nighttime, and all-day warming) and soil depths. Therefore, daytime warming and nighttime warming have different effects on soil variables, although the effects of nighttime warming on soil variables are not always greater than those of daytime warming. Effects of daytime warming and nighttime warming on soil variables are not simple addition or subtraction effects. There are interactions between diurnal asymmetrical warming and no-tillage on soil variables.

Recent Progress in Light Polarization Control Schemes for Silicon Integrated Photonics

AbstractLight polarization control is a target in photonics, and this paper provides a comprehensive review of research from various groups on the silicon‐on‐insulator (SOI) platform. It draws comparisons between devices such as polarization splitters (PS), polarizers, and polarization splitters/rotators (PSR). These devices are fabricated using various technologies, including silicon nanowires, ridge waveguides, hybrid plasmonic waveguides, and subwavelength grating (SWG) waveguides. A detailed review of polarizers used as cleanup filters in splitters is initiated. Subsequently, various polarization splitters utilizing asymmetric directional couplers (ADCs), which typically exhibiting low extinction ratios (ERs), are delved. To enhance ERs, a detailed comparison of methods outlined in the literature is provided. One notable method includes integrating on‐chip polarizers at both ports to eliminate unwanted light fractions and achieve exceptionally high ERs. Furthermore, SWG‐based polarizers and splitters commonly face issues with Bragg reflections that can affect other photonic devices and lasers and ways to minimize unwanted polarization back reflections in SWG‐designed polarization control devices are examined. Finally, emerging applications in mid‐infrared (MIR) sensing are explored, highlighting the necessity of polarization rotators for on‐chip transverse electric (TE) operation, since quantum cascade lasers, the primary sources in this range, emitting radiation in the (TM) mode.

13C evidence for the selective loss of active and inert organic carbon in soil aggregates under rain-induced overland flow erosion

Due to the hierarchical structure of aggregates, raindrops cause changes in the composition, distribution and state of aggregate-wrapped organic carbon (OC) fractions during erosion, greatly affecting soil carbon turnover and sequestration. To explore these regulatory mechanisms, the selective transport of light (LFoc) and heavy (HFoc) fraction OC within aggregates of varying sizes was traced via the 13C/12C carbon isotope ratio (δ13C) under splash and sheet erosion conditions. A “three-zone” variable-slope soil pan was filled with loess soil with a high aggregate concentration to monitor rainfall erosion on a slope. The OC aggregate composition, aggregate stripping and δ13C values of the sediment aggregates of various particle sizes were measured. When the erosion intensity was low, the splash-eroded sediment was mainly enriched in 13C-rich HFoc, and as the rainfall intensity increased, the concentrations of 12C-rich LFoc and HFoc gradually increased. That is, under heavy rainfall, aggregate fragmentation exposed more large fragments rich in younger HFoc and LFoc, and these fragments underwent saltation. There was no obvious correlation between the trends in splash erosion and OC, so runoff transport was an important factor influencing the correlation between δ13C and OC (P < 0.05). Raindrop impact exposed HFoc-rich aggregate fragments of different sizes, e.g., stable mineral-associated OC. Runoff promoted the obvious preferential transport of LFoc and the redistribution of particulate OC (POC) among different sediment particles. Mineral-associated OC and 2–0.05 mm easily decomposable LFoc or POC were preferentially transported, causing OC with the highest and median δ13C values to be preferentially transported. Overall, the transport order of aggregate-exposed OC particles was clay + silt particle-bonded OC, POC, POC-bonded aggregate fragments and silt-bonded aggregate fragments. These results verified the selective loss of aggregate-detached OC fragments during erosion, which led to a change in the OC sequestration and reaggregation potential of OC in the eroded and deposited soil.

Hyperspectral measurements of light backscattering by particles in water with a fixed angle setup: proof of concept and instrument calibration.

The light backscatter signal is the fraction of light scattered at angles greater than 90 degrees with respect to the direction of the incident light. Optical remote sensing platforms collect this signal, which, when measured from the ocean, holds crucial information about its constituents. Interpretation of this signal demands a rigorous understanding of scattering by water and by particles in water. Previous backscatter measurements have mainly focused on resolving the angular distribution of scattering with much less attention given to resolving the wavelength component of backscatter. Most heritage sensors have looked at most 9 wavelengths of light at one scattering angle. Just recently an in situ sensor was presented that can measure backscattering with a 10 nm resolution. Here, we present a laboratory hyperspectral backscatter setup capable of measuring from the ultraviolet to near-infrared wavelengths (320 - 850 nm) at 2 nm resolution.

Chromatic bleaching and fractionation effects on optically stimulated luminescent dosimeter reuse.

Optically stimulated luminescent dosimeters (OSLDs) can be bleached and reused, but questions remain about the effects of repeated bleaching and fractionation schedules on OSLD performance. The aim of this study was to investigate how light sources with different wavelengths and different fractionation schemes affect the performance of reused OSLDs. OSLDs (N=240) were irradiated on a cobalt-60 beam in different step sizes until they reached an accumulated dose of 50Gy. Between irradiations they were bleached using light sources of different wavelengths: the Imaging and Radiation Oncology Core (IROC) bleaching system (our control); monochromatic red, green, yellow, and blue lights; and a polychromatic white light. Sensitivity and linearity-based correction factors were determined as a function of dose step-size. The rate of signal removal from different light sources was characterized by sampling these OSLDs at various time points during their bleaching process. Relative doses were calculated according to the American Association of Physicists in Medicine Task Group-191. Signal repopulation was investigated by irradiating OSLDs (N=300) to various delivered doses of 2, 10, 20, 30, 40, and 50Gy in a single fraction, bleached with one of the colors, and read over time. Fractionation effects were evaluated by irradiating OSLDs up to 30Gy in different size steps. After reading, the OSLDs were bleached following IROC protocol. OSLDs (N=40) received irradiations in 5, 10, 15, 30Gy fractions until they had an accumulated dose of 30Gy; The sensitivity response of these OSLDs was compared with reference OSLDs that had no accumulated dose. Light sources with polychromatic spectrums (IROC and white) bleached OSLDs faster than did sources with monochromatic spectra. Polychromatic light sources (white light and IROC system) provided the greatest dose stability for OSLDs that had larger amounts of accumulated dose. Signal repopulation was related to the choice of bleaching light source, timing of bleaching, and amount of accumulated dose. Changes to relative dosimetry were more pronounced in OSLDs that received larger fractions. At 5-Gy fractions and above, all OSLDs had heightened sensitivity, with OSLDs exposed to 30-Gy fractions being 6.4% more sensitive than reference dosimeters. The choice of bleaching light plays a role in how fast an OSLD is bleached and how much accumulated dose an OSLD can be exposed to while maintaining stable signal sensitivity. We have expanded upon investigations into signal repopulation to show that bleaching light plays a role in the migration of deep traps to dosimetric traps after bleaching. Our research concludes that the bleaching light source and fractionation need to be considered when reusing OSLD.

Long-read subcellular fractionation and sequencing reveals the translational fate of full-length mRNA isoforms during neuronal differentiation.

Alternative splicing (AS) alters the cis-regulatory landscape of mRNA isoforms, leading to transcripts with distinct localization, stability, and translational efficiency. To rigorously investigate mRNA isoform-specific ribosome association, we generated subcellular fractionation and sequencing (Frac-seq) libraries using both conventional short reads and long reads from human embryonic stem cells (ESCs) and neural progenitor cells (NPCs) derived from the same ESCs. We performed de novo transcriptome assembly from high-confidence long reads from cytosolic, monosomal, light, and heavy polyribosomal fractions and quantified their abundance using short reads from their respective subcellular fractions. Thousands of transcripts in each cell type exhibited association with particular subcellular fractions relative to the cytosol. Of the multi-isoform genes, 27% and 19% exhibited significant differential isoform sedimentation in ESCs and NPCs, respectively. Alternative promoter usage and internal exon skipping accounted for the majority of differences between isoforms from the same gene. Random forest classifiers implicated coding sequence (CDS) and untranslated region (UTR) lengths as important determinants of isoform-specific sedimentation profiles, and motif analyses reveal potential cell type-specific and subcellular fraction-associated RNA-binding protein signatures. Taken together, our data demonstrate that alternative mRNA processing within the CDS and UTRs impacts the translational control of mRNA isoforms during stem cell differentiation, and highlight the utility of using a novel long-read sequencing-based method to study translational control.

Geochemical Characteristics of Soil Rare Earth Elements within Spontaneous Combustion Coalfields of Rujigou Coal Mine

(1) Background: The spontaneous combustion of coal (SCC) not only consumes huge amounts of coal resources but also causes environmental degradation. Rare earth elements (REE) can be taken as an effective indicator to evaluate the environmental effects of SCC. Coal in the Rujigou Mine has been spontaneously combusting for hundreds of years. (2) Methods: The geochemical properties of REE and major elements in the soil of the Rujigou coal mine are methodically examined to reveal the environmental effects of SCC. (3) Results: Soil REE concentration in the Rujigou mine is 216.09 mg/kg, and there is an enrichment of light rare earth elements (LREE) and a depletion of heavy rare earth elements (HREE), LREE/HREE in Rujigou mine was 5.52. The spontaneous combustion of coal could change the vertical distribution of REE, which is conducive to the enrichment of LREE. According to the Eu anomaly and δCe/δEu, the source of material in this mine may be derived from the terrigenous clastic rock controlled by weak reduction. Aluminum and titanium have similar geochemical behavior to REE, especially LREE. The concentration of sulfur is negatively correlated with REE, especially HREE. Calcium, sodium, and magnesium all had a negative correlation with LREE. (4) Conclusions: The spontaneous combustion of coal can lead to the fractionation of light and heavy rare earth elements, resulting in the enrichment of LREE and depletion of HREE.

Light manipulation as a route to enhancement of antioxidant properties in red amaranth and red lettuce.

With the growing global population and climate change, achieving food security is a pressing challenge. Vertical farming has the potential to support local food production and security. As a Total Controlled Environment Agriculture (TCEA) system, vertical farming employs LED lighting which offers opportunities to modulate light spectrum and intensity, and thus can be used to influence plant growth and phytochemical composition, including antioxidants beneficial for human health. In this study, we investigated the effect of four red-to-blue light ratios of LEDs (R:B 1, 2.5, 5 and 9) on the growth and antioxidant components in red amaranth microgreens and red lettuce. Plant growth, total phenols, betalains, anthocyanins, vitamin C and antioxidant capacity (ferric reducing antioxidant power assay) were evaluated. A higher proportion of red light resulted in biometric responses, i.e., stem elongation in red amaranth and longer leaves in red lettuce, while the increase in the blue light fraction led to the upregulation of antioxidative components, especially total phenols, betalains (in red amaranth) and anthocyanins (in red lettuce). The antioxidant capacity of both crops was strongly positively correlated with the levels of these phytochemicals. Optimizing the red-to-blue ratio in LED lighting could be effective in promoting antioxidant-rich crops with potential health benefits for consumers.