Impacts of Climate Change on the Biogeography and Ecological Structure of Zelkova schneideriana Hand.-Mazz. in China.

This study utilized the platform for ensemble forecasting of species distributions, biomod2, to predict and quantitatively analyze the distribution changes of Zelkova schneideriana Hand.-Mazz. under different climate scenarios (SSP1-2.6 and SSP5-8.5) based on climate and land-use data. This study evaluated the geographic range changes in future distribution areas and the results indicated that, under both SSP1-2.6 and SSP5-8.5 scenarios, the distribution area of Zelkova schneideriana would be reduced, showing a trend towards migration to higher latitudes and elevations. Particularly, in the more extreme SSP5-8.5 scenario, the contraction of the distribution area was more pronounced, accompanied by more significant migration characteristics. Furthermore, the ecological structure within the distribution area of Zelkova schneideriana also experienced significant changes, with an increasing degree of fragmentation. The variables of Bio6 (minimum temperature of the coldest month), Bio2 (mean diurnal temperature range), Bio15 (precipitation seasonality), and elevation exhibited important influences on the distribution of Zelkova schneideriana, with temperature being particularly significant. Changes in land use, especially the conversion of cropland, had a significant impact on the species' habitat. These research findings highlight the distributional pressures faced by Zelkova schneideriana in the future, emphasizing the crucial need for targeted conservation measures to protect this species and similar organisms.

Regional environmental differences significantly affect the genetic structure and genetic differentiation of Carpinus tientaiensis Cheng, an endemic and extremely endangered species from China.

Differences in topography and environment greatly affect the genetic structure and genetic differentiation of species, and endemic or endangered species with limited geographic ranges seem to be more sensitive to changes in climate and other environmental factors. The complex topography of eastern China is likely to affect genetic differentiation of plants there. Carpinus tientaiensis Cheng is a native and endangered plants from China, and exploring its genetic diversity has profound significance for protection and the collection of germplasm resources. Based on AFLP markers, this study found that C. tientaiensis has low genetic diversity, which mainly came from within populations, while Shangshantou and Tiantai Mountain populations have relatively high genetic diversity. The Nei genetic distance was closely related to geographical distance, and temperature and precipitation notablely affected the genetic variation and genetic differentiation of C. tientaiensis. Based on cpDNA, this study indicated that C. tientaiensis exhibits a moderate level of genetic diversity, and which mainly came from among populations, while Tiantai Mountain population have the highest genetic diversity. It demonstrated that there was genetic differentiation between populations, which can be divided into two independent geographical groups, but there was no significant phylogeographic structure between them. The MaxEnt model showed that climate change significantly affects its distribution, and the suitable distribution areas in Zhejiang were primarily divided into two regions, eastern Zhejiang and southern Zhejiang, and there was niche differentiation in its suitable distribution areas. Therefore, this study speculated that the climate and the terrain of mountains and hills in East China jointly shape the genetic structure of C. tientaiensis, which gived rise to an obvious north-south differentiation trend of these species, and the populations located in the hilly areas of eastern Zhejiang and the mountainous areas of southern Zhejiang formed two genetic branches respectively.

Analysis of Nitrogen Dynamics and Transcriptomic Activity Revealed a Pivotal Role of Some Amino Acid Transporters in Nitrogen Remobilization in Poplar Senescing Leaves.

Leaf senescence is an important developmental process for deciduous trees during which part of leaf nitrogen is remobilized to branches, thus being beneficial for nitrogen conservation. However, the associated regulatory mechanism remains largely unknown in deciduous trees. In this study, nitrogen dynamics and transcriptomic activity in senescing leaves were measured during autumnal senescence in hybrid poplar. Both concentrations of leaf total nitrogen (N) and amine compounds were found to decline from the pre-senescence (PRE) to the middle-senescence (MS) stage. Although the total N concentration decreased further from MS to the late-senescence (LS) and leveled off to abscission (ABS) stage, amine compound concentration increased continuously from MS to ABS, suggesting that translocation of amine compounds underperformed production of amine compounds in leaves during this period. L-glutamate, L-glutamine and α-aminoadipic acid were the top three amine compounds accumulated in senescent leaves. RNA-Seq profiling identified thousands of differentially expressed genes (DEGs) with functional association with a metabolic transition towards disassimilation. Many genes encoding amino acid metabolism enzymes and amino acid transporters (AATs) were up-regulated. Comparison of expression trend with leaf N dynamics and phylogenetic analysis identified several PtAATs which exhibited down-regulation from MS to LS stage and putatively limited leaf N remobilization. This study can serve as a primary basis to further elucidate the molecular mechanisms of nitrogen remobilization in poplar senescing leaves.

Pure Hydrocarbon Materials as Highly Efficient Host for White Phosphorescent Organic Light-Emitting Diodes: A New Molecular Design Approach.

To date, all efficient host materials reported for phosphorescent OLEDs (PhOLEDs) are constructed with heteroatoms, which have a crucial role in the device performance. However, it has been shown in recent years that the heteroatoms not only increase the design complexity but can also be involved in the instability of the PhOLED, which is nowadays the most important obstacle to overcome. Herein, we design pure aromatic hydrocarbon materials (PHC) as very efficient hosts in high-performance white and blue PhOLEDs. With EQE of 27.7 %, the PHC-based white PhOLEDs display similar efficiency as the best reported with heteroatom-based hosts. Incorporated as a host in a blue PhOLED, which are still the weakest links of the technology, a very high EQE of 25.6 % is reached, surpassing, for the first time, the barrier of 25 % for a PHC and FIrpic blue emitter. This performance shows that the PHC strategy represents an effective alternative for the future development of the OLED industry.

Altererythrobacter flava sp. nov., a new member of the family Erythrobacteraceae, isolated from a surface seawater sample.

A Gram-stain-negative, light yellow pigmented, non-motile and aerobic bacterial strain, designated HHU E2-1 T, was isolated from a surface seawater sample. The 16S rRNA gene sequence analysis indicated that HHU E2-1 T shared the highest sequence similarity to the type strain Qipengyuania gaetbuli DSM 16225 T (96.90%), which belongs to the family Erythrobacteraceae. Combined phylogeny of 288 single-copy orthologous gene clusters, analysis of average nucleotide identity (ANI) and digital DNA-DNA hybridization (dDDH), average amino acid identity (AAI) and evolutionary distances suggested that HHU E2-1 T can be considered as a member of the genus Altererythrobacter based on the recently proposed standard for defining genera of Erythrobacteraceae. Strain HHU E2-1 T grew at 15-35 °C and pH 5.0-8.0, with optimum growth at 28 °C and pH 7.0. Tolerance to NaCl was up to 4% (w/v) with optimum growth in 2-3% NaCl. The major fatty acids (> 10%) were C18:1ω7c11-methyl, summed feature 3 (C16:1ω7c and/or C16:1ω6c), and summed feature 8 (C18:1ω7c and/or C18:1ω6c). The predominant isoprenoid quinone was ubiquinone-10. The genomic G + C content was 57.40%. On the basis of the phenotypic, phylogenetic and chemotaxonomic characterizations, HHU E2-1 T represents a novel species of the genus Altererythrobacter, for which the name Altererythrobacter flava sp. nov. is proposed. The type strain is HHU E2-1 T (= CGMCC 1.17394 T = KCTC 72835 T = MCCC 1K04226T).

The complete chloroplast genome of Camellia gauchowensis and its phylogenetic analysis.

Camellia gauchowensis is an economic woody edible oil tree species with high yield per unit area and high ornamental value, which is commonly cultivated in the south of China. The complete chloroplast (cp) genome of C. gauchowensis was assembled and annotated based on the Illumina pair-end sequencing. The whole cp genome of C. gauchowensis is 157,004 bp in size and comprises of a large single-copy (LSC) region of 86,657 bp and a small single-copy (SSC) region of 18,297 bp separated by a pair of inverted repeat (IR) regions of 26,025 bp each. It encodes a total of 129 genes, including 81 protein-coding genes, 5 ribosomal RNA genes, and 43 transfer RNA genes. The neighbor-joining phylogenetic analysis shows that C. gauchowensis is evolutionarily closest to C. cuspidata.

High-Efficiency Red Organic Light-Emitting Diodes with External Quantum Efficiency Close to 30% Based on a Novel Thermally Activated Delayed Fluorescence Emitter.

Researchers have spared no effort to design new thermally activated delayed fluorescence (TADF) emitters for high-efficiency organic light-emitting diodes (OLEDs). However, efficient long-wavelength TADF emitters are rarely reported. Herein, a red TADF emitter, TPA-PZCN, is reported, which possesses a high photoluminescence quantum yield (ΦPL ) of 97% and a small singlet-triplet splitting (ΔEST ) of 0.13 eV. Based on the superior properties of TPA-PZCN, red, deep-red, and near-infrared (NIR) OLEDs are fabricated by utilizing different device structure strategies. The red devices obtain a remarkable maximum external quantum efficiency (EQE) of 27.4% and an electroluminescence (EL) peak at 628 nm with Commission Internationale de L'Eclairage (CIE) coordinates of (0.65, 0.35), which represents the best result with a peak wavelength longer than 600 nm among those of the reported red TADF devices. Furthermore, an exciplex-forming cohost strategy is adopted. The devices achieve a record EQE of 28.1% and a deep-red EL peak at 648 nm with the CIE coordinates of (0.66, 0.34). Last, nondoped devices exhibit 5.3% EQE and an NIR EL peak at 680 nm with the CIE coordinates of (0.69, 0.30).

9,9'-Bicarbazole: New Molecular Skeleton for Organic Light-Emitting Diodes.

Carbazole is a classic tricyclic aromatic compound that has been widely used in organic optoelectronics. Appropriate functionalization on its aromatic rings will significantly increase the possibilities for its application as an optoelectronic material. Position engineering of carbazole not only leads to its structural diversity, but also substantially enriches its functionality. Bicarbazoles have 15 isomers, most of which are well studied and have been applied in organic light-emitting diodes (OLEDs). However, one isomer, 9,9'-bicarbazole, is rarely investigated as an OLED material. Therefore, two 9,9'-bicarbazole derivatives, 3,3'-di(10H-phenoxazin-10-yl)-9,9'-bicarbazole and 3,3'-di(10H-phenothiazin-10-yl)-9,9'-bicarbazole, have been designed and prepared for use as host materials for green and red OLEDs. These two compounds demonstrated good device performances, and it is believed that the 9,9'-bicarbazole building block could be a novel platform for the design of efficient host materials for OLEDs.