Semidiscrete optical vortex droplets in quasi-phase-matched photonic crystals

A new scheme for producing semidiscrete self-trapped vortices (\textquotedblleft swirling photon droplets\textquotedblright ) in photonic crystals with competing quadratic ($\chi ^{(2)}$) and self-defocusing cubic ($\chi ^{(3)}$) nonlinearities is proposed. The photonic crystal is designed with a striped structure, in the form of spatially periodic modulation of the $\chi ^{(2)}$ susceptibility, which is imposed by the quasi-phase-matching technique. Unlike previous realizations of semidiscrete optical modes in composite media, built as combinations of continuous and arrayed discrete waveguides, the semidiscrete vortex droplets are produced here in the fully continuous medium. This work reveals that the system supports two types of semidiscrete vortex droplets, \textit{viz}., onsite- and intersite-centered ones, which feature, respectively, odd and even numbers of stripes, $\mathcal{N}$. Stability areas for the states with different values of $\mathcal{N}$ are identified in the system's parameter space. Some stability areas overlap with each others, giving rise to multistability of states with different $\mathcal{N}$. The coexisting states are mutually degenerate, featuring equal values of the Hamiltonian and propagation constant. An experimental scheme to realize the droplets is outlined, suggesting new possibilities for the long-distance transmission of structured light carrying orbital angular momentum in nonlinear media.Comment: 9 pages, 7 figures, and 82 reference

Modification of N6-methyladenosine RNA methylation on heat shock protein expression.

This study was conducted to investigate effect of N6-methyladenosine (m6A) RNA methylation on Heat shock proteins (HSPs) and dissect the profile of HSP RNA methylation. The results showed that m6A methyltransferases METTL3 mRNA was decreased in responses to heat shock stress in HepG2 cells, but m6A-specific binding protein YTHDF2 mRNA was upregulated in a manner similar to HSP70 induction. Immunofluorescence staining showed that the majority of YTHDF2 was present in the cytosol, however, nearly all YTHDF2 translocated from the cytosol into the nucleus after heat shock. METTL3 knockdown significantly changed HSP70, HSP60, and HSP27 mRNA expression in HepG2 cells using siRNA, however, mRNA lifetime was not impacted. Silence of YTHDF2 using siRNA did not change expression of HSP70, but significantly increased HSP90, HSP60, and HSPB1 mRNA expression. In addition, m6A-seq revealed that HSP m6A methylation peaks are mainly enriched on exons and around stop codons, and shows a unique distribution profile in the 5'UTR and 3'UTR. Knockdown of METTL3 changed the methylation patterns of HSPs transcript. In conclusion, m6A RNA methylation regulates HSP gene expression. Differential expression of HSPs modulated by m6A may depend on the m6A site and abundance of the target gene. This finding provides insights into new regulatory mechanisms of HSPs in normal and stress situations

Vegetation EVI changes and response to natural factors and human activities based on geographically and temporally weighted regression

The research on vegetation changes plays a crucial role in the assessment of ecosystem health, monitoring environmental changes, providing early warnings for natural disasters, and supporting decision-making for sustainable development. However, understanding the nonstationary characteristics of drivers affecting vegetation change remains challenging. This study used Enhanced Vegetation Index (EVI) data obtained through Google Earth Engine (GEE), Theil-Sen, and Mann-Kendall methods to analyze the spatial-temporal patterns and trends of vegetation changes in Sichuan, western China from 2000 to 2020. The Geographical and Temporal Weighted Regression (GTWR) method was applied to deal with spatial and temporal nonstationarity simultaneously. Results showed that vegetation cover in Sichuan was good overall, with medium and high vegetation covering more than 78% of the area. About 72.75% of the area showed an increasing trend in vegetation cover, and areas with extremely significant and significant EVI growth (p < 0.01 and 0.01 ≤ p < 0.05) accounted for 23.94% of the total area. The areas with significant increases in vegetation EVI were mainly distributed in northeast, east, southeast, central, and southwest in Sichuan, while the areas with significant decreases were mainly distributed in the central Sichuan plain urban agglomeration and western Sichuan plateau. GTWR addressed the nonstationary effect of the temporal dimension on the drivers of natural and human activities, with a fitted R2 of 0.846. The study identified climate, terrain, and human activities as the primary driving factors behind vegetation EVI fluctuations. Annual average temperature and precipitation, human activities, and slope had a positive impact on vegetation EVI changes, while solar radiation and aspect had a negative inhibitory effect. The effects of climate, terrain, and human activities on EVI changes exhibited significant spatial heterogeneity and clustering, resulting in either positive promotion or negative inhibition. This study provides an additional methodology to solve the nonstationary problem of vegetation change trends and their response mechanisms. The revealed changes in vegetation EVI and the spatiotemporal heterogeneity characteristics of their driving factors are important for fragile ecosystems to adapt to and mitigate the effects of natural changes and human activities. Revealing the variations in vegetation EVI and their underlying drivers can showcase diverse characteristics across regions and time periods, the presence of spatiotemporal heterogeneity holds great significance in comprehending the adaptive strategies employed by fragile ecosystems to mitigate the effects of natural fluctuations and human-induced activities

Genome-Wide Identification of Maize Protein Arginine Methyltransferase Genes and Functional Analysis of <i>ZmPRMT1</i> Reveal Essential Roles in <i>Arabidopsis</i> Flowering Regulation and Abiotic Stress Tolerance

Histone methylation, as one of the important epigenetic regulatory mechanisms, plays a significant role in growth and developmental processes and stress responses of plants, via altering the methylation status or ratio of arginine and lysine residues of histone tails, which can affect the regulation of gene expression. Protein arginine methyltransferases (PRMTs) have been revealed to be responsible for histone methylation of specific arginine residues in plants, which is important for maintaining pleiotropic development and adaptation to abiotic stresses in plants. Here, for the first time, a total of eight PRMT genes in maize have been identified and characterized in this study, named as ZmPRMT1-8. According to comparative analyses of phylogenetic relationship and structural characteristics among PRMT gene family members from several representative species, all maize 8 PRMT proteins were categorized into three distinct subfamilies. Further, schematic structure and chromosome location analyses displayed evolutionarily conserved structure features and an unevenly distribution on maize chromosomes of ZmPRMT genes, respectively. The expression patterns of ZmPRMT genes in different tissues and under various abiotic stresses (heat, drought, and salt) were determined. The expression patterns of ZmPRMT genes indicated that they play a role in regulating growth and development and responses to abiotic stress. Eventually, to verify the biological roles of ZmPRMT genes, the transgenic Arabidopsis plants overexpressing ZmPRMT1 gene was constructed as a typical representative. The results demonstrated that overexpression of ZmPRMT1 can promote earlier flowering time and confer enhanced heat tolerance in transgenic Arabidopsis. Taken together, our results are the first to report the roles of ZmPRMT1 gene in regulating flowering time and resisting heat stress response in plants and will provide a vital theoretical basis for further unraveling the functional roles and epigenetic regulatory mechanism of ZmPRMT genes in maize growth, development and responses to abiotic stresses

Quantifying urban expansion and its driving forces in Chengdu, western China

Understanding urban sprawl and its drivers is crucial for sustainable urban development. Most studies on Chinese urbanization have focused on coastal areas, paying little attention to urban centers in western China. This study examines urban expansion based on the Google Earth Engine (GEE), remotely sensed image, urban expansion model, and analysis of buffer and quadrant location in the Geographic Information System (GIS). Additionally, driving forces of urban expansion are examined based on the principle component analysis (PCA). Results indicate that urban land area increased more than 5.60 times, reaching 124,723 ha, an increase of over 400 % during 1990–2020. The urban expansion rate and intensity significantly increased and exhibited spatio-temporal heterogeneity. We identified that urban spatial expansion patterns changed from patch filling to patch border expansion, and urban expansion direction was mainly in the southern, northeastern, southwestern, and northwestern regions, extending along the traffic corridor, ring road, and adjacent cities. We suggest that economic development, population, and urbanization have become the driving factors of urban expansion. The GEE provides a new geographic processing algorithm based on massive image datasets, facilitating remote sensing processing. The results revealed that Chengdu is following trends witnessed in coastal cities of China; however, the significance of various drivers of urban expansion in these cities differs from that of the eastern cities. This study will help formulate policies for better urban land management and sustainable land development

Li metal anode interface in sulfide‐based all‐solid‐state Li batteries

Abstract Sulfide solid electrolyte (SSE)‐based all‐solid‐state Li batteries (ASSLBs) can overcome the problems of low energy density and safety concern of current Li‐ion batteries. However, the practical application of SSE‐based ASSLBs is suffered from several problems, especially interfacial issues between Li metal anode (LMA) and SSEs. Therefore, in this study, the problems of the LMA–SSE interface and their corresponding solutions are reviewed. First, the interfacial problems are summarized, namely the side reactions of SSEs, the Li dendrite growth, and poor contact between the electrode and electrolyte. Second, the available strategies to improve the robustness of the interface are discussed, including the protection of the LMA, substitution of the LMA, and modification of SSEs. Third, the characterization methods used to analyze the morphological and compositional evolution of the interface during cycling are introduced. Finally, the limitations and future research directions are proposed

Effect of METTL3 knockdown on the lifetime of HSPA1B in HepG2 cells.

<p>Lifetime of <i>HSPA1B</i> (<i>HSP70</i>) mRNA in the samples following knockdown of <i>METTL3</i> in HepG2 cells (<b>A</b>). The relative mRNA levels of <i>HSPA1B</i> (<i>HSP70</i>) in the samples following knockdown of <i>METTL3</i> in HepG2 cells at 0 h, 3 h, and 6 h (<b>B</b>).</p

Effect of YTHDF2 on HSPs mRNA expression and cell viability in HepG2 cells.

<p>YTHDF2 knockdown decreased YTHDF2 mRNA in HepG2 cells (<b>A</b>). Expression of <i>HSPA1B</i> (<i>HSP70</i>), <i>HSPA9</i> (<i>HSP70</i>), <i>HSPB1</i> (<i>HSP27</i>), <i>HSP90AA1</i> (<i>HSP90</i>), <i>HSPD1</i> (<i>HSP60</i>) mRNA from the sample of YTHDF2 knockdown in HepG2 cells (<b>B</b> and <b>C</b>). The relative cell viability determined by MTT at 24, 48, and 72 h after knockdown of YTHDF2 with or without heat shock pretreatment (<b>D</b>) (n = 6). Data are shown as mean ± SEM. *<i>p</i> value ≤ 0.05, **<i>p</i> value ≤ 0.01.</p

Effect of METTL3 knockdown on HSPs and cell viability in HepG2 cells.

<p>Expression of <i>METTL3</i> mRNA and protein in HepG2 cells after METTL3 knockdown (<b>A</b> and <b>B</b>). (n = 3). Expression of <i>HSPA1B</i> (<i>HSP70</i>), <i>HSPA9</i> (<i>HSP70</i>), <i>HSP90AA1</i> (<i>HSP90</i>), <i>HSPD1</i> (<i>HSP60</i>), <i>HSF1</i>, and <i>HSPB1</i> (<i>HSP27</i>) mRNA upon METTL3 knockdown in HepG2 cells <b>(C)</b> (n = 3). The relative cell viability determined by MTT at 24, 48, and 72 h post-transfection of METTL3 siRNA with or without heat shock pretreatment (<b>D</b>) (n = 6). Data are shown as mean ± SEM. *<i>p</i> value ≤ 0.05, **<i>p</i> value ≤ 0.01.</p

M⁶A methylated peaks of HSPs mRNA.

<p>Integrative genomics viewer (IGV) plots showing m⁶A methylated peaks for <i>HSPA1B</i> (<i>HSP70</i>) (<b>A</b>), <i>HSPB1</i> (<i>HSP27</i>) (<b>B</b>), <i>HSPA9</i> (<i>HSP70</i>) (<b>C</b>), <i>HSP90AA1</i> (<i>HSP90</i>) (<b>D</b>), <i>HSPD1</i> (<i>HSP60</i>) (<b>E</b>), <i>HSF1</i> (<b>F</b>) mRNA in HepG2 cells. Blue boxes represent exons and blue lines represent introns. <i>n</i> = 2.</p