L2 Layers Research Articles

Paleoenvironmental Transition during the Rhuddanian–Aeronian and Its Implications for Lithofacies Evolution and Shale Gas Exploration: Insights from the Changning Area, Southern Sichuan Basin, South-West China

During the Rhuddanian–Aeronian interglacial period, global geological events such as glacial melting, synsedimentary volcanic activity, biological resurgence, and large-scale marine transgressions caused frequent fluctuations in paleoproductivity, climate changes, and sea level variations. These paleoenvironmental transitions directly influenced the development characteristics of shale lithofacies. This study investigates the Longmaxi Formation shale in the Changning area in the Southern Sichuan basin, focusing on 28 core samples from Well N1. Using scanning electron microscopy, QEMSCAN, TOC, XRD, and major and trace element analyses, we reconstructed the paleoenvironmental transitions of this period and explored their control over shale lithofacies types and mineral compositions. Four shale lithofacies were identified: carbonate rich lithofacies (CRF), biogenic quartz-rich lithofacies (BQRF), detrital clay-rich lithofacies (CRDF), and detrital quartz-rich lithofacies (DQRF). During the Rhuddanian period, rising global temperatures caused glacial melting and rapid marine transgressions. The low oxygen levels in bottom waters, combined with upwelling and abundant volcanic material, led to high paleoproductivity. This period primarily developed BQRF and CRF. Rich nutrients and abundant siliceous organisms, along with anoxic to anaerobic conditions, provided the material basis and preservation conditions for high biogenic quartz and organic matter content. High paleoproductivity and anoxic conditions also facilitated the precipitation of synsedimentary calcite and supplied Mg2+ and SO42− for the formation of iron-poor dolomite via sulfate reduction. From the Late Rhuddanian to the Mid-Aeronian, the Guangxi orogeny caused sea levels to fall, increasing water oxidation and reducing upwelling and volcanic activity, which lowered paleoproductivity. Rapid sedimentation rates, stepwise global temperature increases, and the intermittent intensification of weathering affected terrigenous clastic input, resulting in the alternating deposition of CRF, CRDF, and DQRF. Two favorable shale gas reservoirs were identified from the Rhuddanian–Aeronian period: Type I (BQRF) in the L1–L3 Layers, characterized by high TOC and brittleness, and Type II (DQRF) in the L4 Layer, with significant detrital quartz content. The Type I-favorable reservoir supports ongoing gas production, and the Type II-favorable reservoir offers potential as a future exploration target.

Analysis of corporate network cyber threats based on parallel processing of Netflow data

Public services of various organizations are subject to constant cyber attacks, which increases information security risks. Network traffic analysis is an important task to ensure the safe operation of network infrastructure, including corporate networks. This paper provides an overview of the main approaches for analyzing network traffic, provides related works, and points out the shortcomings of existing works. One method is to analyze network traffic data using the Netflow protocol, which allows traffic data to be stored at the L3 layer of the OSI model. A feature of the study is the use of long observation periods. When storing data over long time intervals, the logs become large, which requires parallelization for primary data processing. The authors developed a cross-platform software package for distributed processing of network activity logs, which was used to analyze the network activity of the corporate network of the Krasnoyarsk Scientific Center for 2021–2022. A diagram of the software package is shown, its capabilities and operating features are described. Data sources for analysis and processing methods are provided. In this paper the authors formulated and formalized heuristic criteria for the anomaly of network traffic, which identify the presence of possible network attacks, and extracted datasets on the network activity of various application-level protocols. For the obtained data sets, statistical indicators were calculated, information about anomalous network activity was obtained for two years. In this work we tested the previously proposed method for comparing the cyber threats risks for different time intervals, which showed a significant increase in risks for 50% of indicators in 2022. Comparisons of monthly intervals over different years showed similar increases in risk. Thus, the method has shown its efficiency and can be used in other areas in which there are groups of criteria for independent indicators. The authors proposed plans for further development of methods for analyzing network activity.

Translucent multi-layered zirconia: Sandblasting effect on optical and mechanical properties.

The aim of this study was to evaluate the influence of the sandblasting treatment on the microstructure, optical and mechanical properties of multi-layered translucent zirconia. Samples of yttria-stabilized zirconia were prepared by stratifying four layers (L1, L2, L3 and L4) of ML-type KATANA multi-layered monolithic discs, whose surfaces were then sandblasted with alumina particles (110µm and 0.2MPa) in order to evaluate its effect on the presence of different crystalline phases as well as on the optical and mechanical properties of each of the four layers. The optical characterization was carried out by measuring the reflectance spectrum and colorimetric parameters by UV-Vis spectrophotometric analysis and the transmittance curves were indirectly obtained using the Kubelka-Munk model (KM). Microstructural, structural, mechanical and roughness characterizations were also performed using SEM, XRD, biaxial flexural strength B3B, and light interferometry, respectively RESULTS: According to the KM model there are different degrees of translucency between the upper and lower layers of the monolithic discs, but there was no influence of the Al2O3-sandblasting treatment on this optical property. The disk pigmentation causes greater absorption of light below 600nm, decreasing the transmittance rate to values below 25% in this region of the spectrum. The yellowing index presented higher values for inner disk layers L3 and L4, in agreement with the highest values of the light absorption coefficient K observed for these layers. The roughness of the samples did not change significantly with the surface treatment performed and the sandblasting did not result in new crystalline phases. SEM analysis showed the presence of different grain sizes in all layers analyzed, being related to the co-occurring presence of cubic (c-ZrO2) and tetragonal (t-ZrO2) phases in similar contents (∼ 50wt%). The Weibull statistical analysis, in turn, showed an increase in the Weibull characteristic stress value (σ0) for most layers subjected to sandblasting, except for the second layer (central region of the disk). It was also verified an increase in the value of the structural reliability of the material (m), referring to the samples of the central region of the disc (L2 and L3 layers) after sandblasting. The pigmentation in the disk causes a decrease of the transmittance rate to values well below 25% in the region of the spectrum 400-600nm and the inner layers (L3 and L4) have even lower transmittance than the outer layers in this spectrum range. Although the CR index indicates variation related to the Al2O3-sandblasting treatment, the transmittance spectra of KM model show that the sandblasting did not cause a significant change in the transmittance rate of the four analyzed layers. Also, there is no significant difference in the light scattering of the different layers of the disc, either before or after Al2O3-sandblasting treatment.

Characteristics of agricultural phosphorus migration in different soil layers on purple soil sloping cropland under natural rainfall conditions

Limited by the current monitoring and collection methods of subsurface flow data, the characteristics of phosphorus (P) migration loss in different soil layers on sloping cropland under natural rainfall conditions need to be clarified. In this study, a reliable U-trough collection method was used to explore P migration losses in different purple soil layers (L0: surface, L1: 0–20 cm, L2: 20–40 cm, and L3: 40–60 cm) for purple soil sloping cropland during a field monitoring campaign spanning two calendar years under natural rainfall conditions. The results suggested that the annual surface P loss load was 1.08 kg*ha−1*yr−1, where 92.1% was particulate P. The annual leaching loss load of total P from the L1 layer was 3.55 kg*ha−1*yr−1, where 74.2% and 10.5% were intercepted by the L2 and L3 layers, respectively, to increase the in situ soil P stocks. Only 15.3% of L1’s annually leached P, and only half the surface P loss load (L0), was lost to underground water. Heavy-rain events on the purple soils in the studied sloping cropland induced 43.9% of the annual surface P loss load. In contrast, 36.1%, 30.5%, and 30.3% of P’s eventual annual leached loss loads resulted from heavy, moderate, and torrential rain events, respectively. The maize season was the main period of surface and subsurface P migration loss. Due to the limitation of experimental conditions, the results of this experiment could not represent the soil phosphorus migration process in the natural purple slope farmland in nature, but it could partially represent the soil phosphorus migration in the newly cultivated purple sloping cropland in Chongqing.

Development Adjustment Scheme of a Low-Permeability Reservoir in the SN Oilfield

Due to the complexity of low-permeability reservoirs, there is no set of established plans to adjust the development of specific low-permeability reservoirs, and the final development adjustment plan should be determined through comprehensive consideration of many aspects. At present, the development of low-permeability reservoirs in the SN oilfield faces problems. It is urgent to formulate corresponding development adjustment plans to improve the current development situation. In view of the problems of the current development surface of low-permeability reservoirs in the SN oilfield, this paper used the previous research results of a low-permeability reservoir development adjustment for reference, evaluated the reservoir development effect, analyzed the remaining oil distribution via numerical reservoir simulation, and finally designed and optimized a development adjustment plan. The research results show that the injection–production ratio and pressure of low-permeability reservoirs in the SN oilfield were generally maintained, the oil production decreased, the water cut increased, and the remaining recoverable reserves were considerable; the historical matching quality of a reservoir numerical simulation was good. There was more remaining oil in the northeast of the J007 well block and the north of the J008 well block, and the potential of the L2 and L3 layers was great. The remaining oil was mainly concentrated in the areas with high positions, poor physical properties, and imperfect well patterns; the predicted cumulative oil production of Scheme IV in 15 years and recovery were the highest, with the best development effect and the highest economic benefit. This was determined as the development adjustment plan for low-permeability reservoirs in the SN oilfield. The research results of this paper aim to improve oil production, the ultimate recovery factor, and economic benefits of low-permeability reservoirs in the SN oilfield, and to provide a reference for the development of similar oilfields.

Thermal responsive smart lanthanide luminescent hydrogel actuator

Among stimuli-responsive soft materials, thermal responsive hydrogels are the most attractive one because temperature is the most easily regulated external stimuli. We here report a thermal responsive bilayer smart luminescent hydrogel actuator with tough mechanical strength and thermal reversible deformation behavior. The bilayer hydrogel is composed of Poly(N-isopropylacrylamide)-Laponite-Tb complex (PNIPAM-Lap-Tb·L3) layer and Poly(N,N-dimethylacrylamide)-Laponite-Eu complex (PDMA-Lap-Eu·L3) layer. Upon alternative heating and cooling, the PNIPAM-Lap-Tb·L3 layer undergoes reversible shrink and expansion, while the PDMA-Lap-Eu·L3 layer is not affected, leading to asymmetric deformation behavior. The luminescent intensity of the bilayer hydrogel was enhanced by heating, and the maximum bending angle was 371° in 15 min. By processing the bilayer hydrogel into complex 2D and 3D structure, we further demonstrate their great potential as smart soft actuators.

Signaling by the EPFL-ERECTA family coordinates female germline specification through the BZR1 family in Arabidopsis.

In most flowering plants, the female germline is initiated in the subepidermal L2 layer of ovule primordia forming a single megaspore mother cell (MMC). How signaling from the L1 (epidermal) layer could contribute to the gene regulatory network (GRN) restricting MMC formation to a single cell is unclear. We show that EPIDERMAL PATTERNING FACTOR-like (EPFL) peptide ligands are expressed in the L1 layer, together with their ERECTA family (ERf) receptor kinases, to control female germline specification in Arabidopsis thaliana. EPFL-ERf dependent signaling restricts multiple subepidermal cells from acquiring MMC-like cell identity by activating the expression of the major brassinosteroid (BR) receptor kinase BRASSINOSTEROID INSENSITIVE 1 and the BR-responsive transcription factor BRASSINOZOLE RESISTANT 1 (BZR1). Additionally, BZR1 coordinates female germline specification by directly activating the expression of a nucleolar GTP-binding protein, NUCLEOSTEMIN-LIKE 1 (NSN1), which is expressed in early-stage ovules excluding the MMC. Mutants defective in this GRN form multiple MMCs resulting in a strong reduction of seed set. In conclusion, we uncovered a ligand/receptor-like kinase-mediated signaling pathway acting upstream and coordinating BR signaling via NSN1 to restrict MMC differentiation to a single subepidermal cell.

Microneedle Array-Assisted, Direct Delivery of Genome-Editing Proteins Into Plant Tissue

Genome editing in plants employing recombinant DNA often results in the incorporation of foreign DNA into the host genome. The direct delivery of genome-editing proteins into plant tissues is desired to prevent undesirable genetic alterations. However, in most currently available methods, the point of entry of the genome-editing proteins cannot be controlled and time-consuming processes are required to select the successfully transferred samples. To overcome these limitations, we considered a novel microneedle array (MNA)-based delivery system, in which the needles are horizontally aligned from the substrate surface, giving it a comb-like configuration. We aimed to deliver genome-editing proteins directly into the inner layers of leaf tissues; palisade, the spongy and subepidermal L2 layers of the shoot apical meristem (SAM) which include cells that can differentiate into germlines. The array with needles 2 μm wide and 60 μm long was effective in inserting into Arabidopsis thaliana leaves and Glycine max (L.) Merr. (soybeans) SAM without the needles buckling or breaking. The setup was initially tested for the delivery of Cre recombinase into the leaves of the reporter plant A. thaliana by quantifying the GUS (β-glucuronidase) expression that occurred by the recombination of the loxP sites. We observed GUS expression at every insertion. Additionally, direct delivery of Cas9 ribonucleoprotein (RNP) targeting the PDS11/18 gene in soybean SAM showed an 11 bp deletion in the Cas9 RNP target site. Therefore, this method effectively delivered genome-editing proteins into plant tissues with precise control over the point of entry.

Brassinosteroid signaling regulates female germline specification in Arabidopsis

Unlike in humans and animals, plant germlines are specified de novo from somatic cells in the reproductive organs of the flower. In most flowering plant ovules, the female germline starts with the differentiation of one megaspore mother cell (MMC), which initiates a developmental program distinct from adjoining cells. Phytohormones act as a key player in physiological processes during plant development, in particular by providing positional information that supports localized differentiation events. However, little is known about the role of phytohormones for female germline initiation and establishment. Using Arabidopsis as a flowering plant model, we show that brassinosteroid (BR) biosynthesis and signaling components are accumulated in sporophytic cells of ovule primordia but not in the megaspore mother cell representing the precursor of the female germline. We further demonstrate that BR signaling restricts multiple sub-epidermal cells in the distal nucellus region of ovule primordia from acquiring MMC-like cell identity by transiently activating the WRKY23 transcription factor, expressed exclusively in L2 layer cells adjacent to the MMC. This activation is regulated through the BRI1 receptor and directly by the BZR1 transcriptional repressor family. Mutations in BR biosynthesis or signaling components and ectopic activation of BR signaling in MMCs induce multiple MMC-like cells. In summary, our findings elucidate a gene regulatory network that shows how the hormone BR generated in sporophytic ovule primordia cells restricts the origin of the female germline to a single cell.

Measuring the Damping Performance of Gradient-Structured Bamboo Using the Resonance Method

Bamboo has natural damping properties, but, due to the obvious gradient differences in bamboo walls, the damping properties of different layers may vary. Using bamboo slivers as the research object, this study investigated the underlying mechanism of the effect of microstructural and chemical components on the damping properties (η, damping ratio) of bamboo using the resonance and nonresonance methods. The damping ratio decreased on L3 (inner layer), L2 (middle layer), and L1 (outer layer) due to lower microfibril angles, increased crystallinity of cellulose, and decreased hemicellulose content. All of these limited the motion of the bamboo’s molecular chains. The damping ratio successively increased in the oven-dried, air-dried, and water saturated states because water acted as a plasticizer. The damping ratio of L1, in the oven-dried state, was slightly higher than that of the air-dried state because L1 had the lowest water content. This allowed less water to escape during drying, which intensified the molecular distortion. The initial tan δ (tangent of the loss angle) decreased successively on the L3, L2, and L1 layers of the bamboo, and the tan δ of L3 was lower than that of L2 due to changes in the temperature sensitivity of hemicellulose.

Morphological Characterization of Tetraploids of Limonium sinuatum (L.) Mill. Produced by Oryzalin Treatment of Seeds

Limonium sinuatum (L.) Mill. (2n = 2x = 16) is a popular ornamental plant with dimorphism of pollen grains (type A and type B) and stigmas (papilla and cob-like). We applied polyploidy breeding to this species in order to introduce desirable traits. Tetraploid and mixoploid L. sinuatum plants were successfully obtained with oryzalin treatment of L. sinuatum ‘Early Blue’ seeds. All three tetraploids had increased leaf width, stomatal size, flower length, and pollen width compared to those of the diploid, and tetraploids had four germinal pores of pollen grains, whereas the diploid had three. All tetraploids had type A pollen grains and cob-like stigmas. Furthermore, the growth of cultivated tetraploid plants was slow, with later bolting and flowering times. Mixoploids Mixo-1 and Mixo-3 were estimated to be polyploidy periclinal chimeric plants consisting of a tetraploid L1 layer and diploid L2 layer, and Mixo-2 was estimated to be a polyploidy periclinal chimeric plant consisting of the diploid L1 layer and tetraploid L2 layer. Mixo-4 had tetraploid L1 and L2 layers. Mixoploids, except Mixo-4, had type A pollen grains and cob-like stigmas, whereas Mixo-4 had type B pollen grains and papilla stigmas. These polyploids will be useful as polyploidy breeding materials.

Application of stable carbon and hydrogen isotope technology in the determination of gas sources from limestone layers at Shuangliu mine, China

AbstractStable carbon and hydrogen isotope technology is used in determining gas sources in coal mines. Coal measures at the Shuangliu mine mainly contain nine coal seams (i.e. No. 2 to No. 10) and five limestone layers (namely, L1 to L5). The coal seams are interbedded with the limestone layers. A large amount of methane is adsorbed in the limestone layer, and the actual measured maximum gas pressure is 1.3 MPa, posing a serious gas emission safety risk in roadway excavation in the coal measures. In order to effectively manage the safety risk of gas emissions, it is necessary to determine gas sources and take necessary control measures. In this study, 50 gas samples were taken from the coal seams and 10 gas samples were collected from the limestone layers. These samples were measured for their composition and stable carbon and hydrogen isotopes. Stable carbon and hydrogen isotope tracer separation technique and multi-source linear calculation methods were used to analyze the measurement results. The study shows that 84% of gas in the L1, L2 and L3 limestone layers comes from the No. 8 coal seam and 11% from the No. 9 coal seam; gas in the L4 limestone layer is mainly from the No. 8 (44%), No. 7 (37%) and No. 6 coal seams (16%), and gas in L5 limestone layer mainly comes from the No. 6 (59%), No. 7 (23%) and No. 8 coal seams (13%). The research results can guide the design of gas drainage boreholes before roadway tunneling, so it has important guiding significance in the formulation of comprehensive gas control schemes.

A single-cell analysis of the Arabidopsis vegetative shoot apex.

The shoot apical meristem allows for reiterative formation of new aerial structures throughout the life cycle of a plant. We use single-cell RNA sequencing to define the cellular taxonomy of the Arabidopsis vegetative shoot apex at the transcriptome level. We find that the shoot apex is composed of highly heterogeneous cells, which can be partitioned into 7 broad populations with 23 transcriptionally distinct cell clusters. We delineate cell-cycle continuums and developmental trajectories of epidermal cells, vascular tissue, and leaf mesophyll cells and infer transcription factors and gene expression signatures associated with cell fate decisions. Integrative analysis of shoot and root apical cell populations further reveals common and distinct features of epidermal and vascular tissues. Our results, thus, offer a valuable resource for investigating the basic principles underlying cell division and differentiation in plants at single-cell resolution.

Somatic embryogenesis is an effective strategy for dissecting chimerism phenomena in Vitis vinifera cv Nebbiolo.

The tendency of somatic embryogenesis to regenerate plants only from the L1 layer, associated with the spread of chimerism in grapevine, must be carefully considered in the framework of biotechnological improvement programmes. Grapevine is an important fruit crop with a high economic value linked to traditional genotypes that have been multiplied for centuries by vegetative propagation. In this way, somatic variations that can spontaneously occur within the shoot apical meristem are fixed in the whole plant and represent a source of intra-varietal variability. Previously identified inconsistencies in the allelic calls of single nucleotide variants (SNVs) suggested that the Vitis vinifera 'Nebbiolo' CVT185 clone is a potential periclinal chimera. We adopted the somatic embryogenesis technique to separate the two genotypes putatively associated with the L1 and L2 layers of CVT185 into different somaclones. Despite the recalcitrance of 'Nebbiolo' to the embryogenic process, 58 somaclones were regenerated and SNV genotyping assays attested that the genotype of all them differed from that of the mother plant and was only attributable to L1. The results confirmed that L2 has low or no competence for differentiating somatic embryos. After one year in the greenhouse, the somaclones showed no phenotypic alterations in comparison with the mother plant; however further analyses are needed to identify potential endogenous sources of variation. The tendency of somatic embryogenesis to regenerate plants only from L1 must be carefully considered in the framework of biotechnological improvement programmes in this species.

Color Intensity of the Red-Fleshed Berry Phenotype of Vitis vinifera Teinturier Grapes Varies Due to a 408 bp Duplication in the Promoter of VvmybA1.

Grapevine (Vitis vinifera) teinturier cultivars are characterized by their typical reddish leaves and red-fleshed berries due to ectopic anthocyanin formation. Wines of these varieties have economic importance as they can be used for blending to enhance the color of red wines. The unique and heritable mutation has been known for a long time but the underlying genetic mechanism still is not yet understood. Here we describe the association of the red-fleshed berry phenotype with a 408 bp repetitive DNA element in the promoter of the VvmybA1 gene (grapevine color enhancer, GCE). Three different clones of ‘Teinturier’ were discovered with two, three and five allelic GCE repeats (MybA1t2, MybA1t3 and MybA1t5). All three clones are periclinal chimeras; these clones share the same L1 layer, but have distinct L2 layers with different quantities of GCE repeats. Quantitative real time PCR and HPLC analysis of leaf and berry samples showed that the GCE repeat number strongly correlates with an increase of the expression of VvmybA1 itself and the VvUFGT gene regulated by it and the anthocyanin content. A model is proposed based on autoregulation of VvmybA1t to explain the red phenotype which is similar to that of red-fleshed apples. This study presents results about the generation and modes of action of three MybA1t alleles responsible for the red-fleshed berry phenotype of teinturier grapevines.

The Study of Gaining More Detailed Variability Information of Soil Organic Carbon in Surface Soils and Its Significance to Enriching the Existing Soil Database

To meet the increasing demands of precision agricultural and environmental management, more abundant and accurate information is needed to describe soil organic carbon (SOC) vertical variation. Based on 923 soil profiles (collected at the depths of 0–15, 15–30, 30–60, 60–90, 90–120, and 120–150 cm) in the central area of Changhua County, Taiwan, the distribution curve of the SOC content of each profile was fitted by the equal-area spline model, and it was possible to obtain the SOC content at all depths. Taking the 0–5 cm (L1), 5–10 cm (L2), and 10–15 cm (L3) sub-layers as examples, their SOC contents and stocks were compared to the mean values of the average 5-cm-thick sub-layers (Lm) derived from the value of the 0–15 cm layer. The results indicated that the SOC contents and stocks both reduced with increasing soil depths. The mean SOC contents of L1, L2, and L3 were 22.1, 21.0, and 18.7 g·kg−1, respectively, with significant variation, and the values of L2 and L3 were 5.0% and 15.4% lower than that of L1. Similarly, the mean SOC stocks were 1.29, 1.25, and 1.16 kg·m−2 of the L1, L2, and L3 layers, also with significant variation, and the values of L2 and L3 were 4.0% and 10.1% lower than that of L1. Meanwhile, it was found that the SOC content and stock of Lm were both close to the corresponding values in L2, but were significantly different to that of L1 and L3. Furthermore, the interpolation contours of the SOC contents and stocks in L1, L2, and L3 by digital soil mapping also presented regular variation with increasing soil depths, while the contours of Lm had nearly identical patterns to that of L2. The results demonstrate that the typically used mean SOC contents with certain thicknesses calculated from the sampling layer can only approximately inflect the SOC situation at intermediate depths, but the SOC content in the upper and lower parts within the sampling layer varies greatly. Therefore, the actual distribution of SOC varies gradually depending on the soil depth. This study indicates that the combination of the equal-area spline model and digital soil mapping can greatly enrich the current soil SOC database and provide more abundant and accurate SOC content and stock information for precision agricultural and environmental management based on legacy soil database.

Biochemical composition distribution in different grain layers is associated with the edible quality of rice cultivars

Clarifying the association of differences in endosperm biochemical composition with nutrient and edible quality can guide rice breeding and cultivation. In this study, very-low-amylose-content (LAC), Japanese good-taste (JTC), Northeast China good-taste (CTC), and Northeast China high-yield (CHC) cultivars were milled to obtain four layers (L1-L4) from outside-in, and then analyzed for apparent amylose content (AAC), protein content (PC), amino acids, soluble sugars, and minerals. The association of these compositions and Rapid-Visco analysis values with taste was also examined. LAC had low AAC, high amino acid and mineral content, and the highest taste value. Taste was significantly affected by AAC and soluble sugar in L3, and by PC in the L2 layer. High levels of amino acid in L2 and L3 improved the taste, as did Mg, P, and Ca in L1. On the whole, starch factors had the highest contribution to taste, followed by minerals, amino acids, and PC.

Investigation of the structure of ramie fibers by enzymatic peeling

Ramie offers excellent wearability compared to other fibrous material; however, since the inner structure of the fibers remains largely unexplored, this excellent wearability lacks a reasonable explanation. In this study, enzymatic peeling, using xylanase and laccase coupled with PM, FLSM, and SEM, was confirmed to be an effective and efficient method to characterize the inner structure of ramie fibers. The surface of bio-degummed ramie fibers is smooth, has a fibrillar structure and contains dislocations including kinks, nodes, and scales. The transverse structure is multilayered (designated as L1, L2, and L3 layers) and has a big compressed lumen. The L1 layer is the outermost layer, which shows bright indigo fluorescent signals that indicate xylan. After removal of the L1 layer via enzymatic treatment, fibers become twisted and cracked, and the fibrillar and buckled secondary cell wall structure clarifies. Under laccase treatment, visible pores can be exposed on the secondary wall, including pit-like pores on the bulk of the cell walls and irregular pores lined at the dislocation region. L3 was identified as the innermost layer. Almost the complete L3 layer was separated from the secondary wall, using an enzymatic peeling method, and showed a closed, round, and blunt tube end and a honeycomb-like inner structure. The mesopores were filled with pectin and the surface of the tube emitted a blue fluorescent signal. The honeycomb-like innermost layer together with the pore structure of the secondary wall forms a physical basis for the cause of special wearabilities such as the shrinkage, absorbency, and scratchiness of ramie fibers.

Mechanism of Carbon Diffusion in the Iron Sheet During Gas–Solid Decarburization

To investigate the diffusion of carbon in the iron sheet during gas–solid decarburization in a weak oxidative atmosphere (Ar + H2 + H2O), the microstructures of iron sheets following decarburization were observed through SEM. The carbon gradient following decarburization in the iron sheet along the thickness direction was detected in this study. The results showed that the iron sheet along the thickness direction following decarburization consisted of three layers: the L1 layer (ferrite phase) that was near the surface, the L2 layer (cementite phase) that was between the L1 + L3 layers, and the L3 layer (cementite + ferrite + graphite phase) that was in the center of the sample. The depth of the decarburization layer (L1 + L2) showed a good linear relation with the square root of the decarburization time. The carbon gradient in iron sheet along the thickness direction was of ladder type during decarburization. The carbon content in the center of iron sheet was influenced by the decarburization time or the temperature. The carbon migration in iron sheet consisted of stable carbon decomposition and free carbon diffusion. The carbon migration in the S2 stage of iron sheet was the controlling step of the entire decarburization process.

Differential impacts of FtsZ proteins on plastid division in the shoot apex of Arabidopsis

FtsZ proteins of the FtsZ1 and FtsZ2 families play important roles in the initiation and progression of plastid division in plants and green algae. Arabidopsis possesses a single FTSZ1 member and two FTSZ2 members, FTSZ2-1 and FTSZ2-2. The contribution of these to chloroplast division and partitioning has been mostly investigated in leaf mesophyll tissues. Here, we assessed the involvement of the three FtsZs in plastid division at earlier stages of chloroplast differentiation. To this end, we studied the effect of the absence of specific FtsZ proteins on plastids in the vegetative shoot apex, where the proplastid-to-chloroplast transition takes place. We found that the relative contribution of the two major leaf FtsZ isoforms, FtsZ1 and FtsZ2-1, to the division process varies with cell lineage and position within the shoot apex. While FtsZ2-1 dominates division in the L1 and L3 layers of the shoot apical meristem (SAM), in the L2 layer, FtsZ1 and FtsZ2-1 contribute equally toward the process. Depletion of the third isoform, FtsZ2-2, generally resulted in stronger effects in the shoot apex than those observed in mature leaves. The implications of these findings, along with additional observations made in this work, to our understanding of the mechanisms and regulation of plastid proliferation in the shoot apex are discussed.