A conserved but plant-specific CDK-mediated regulation of DNA replication protein A2 in the precise control of stomatal terminal division

The R2R3-MYB transcription factor FOUR LIPS (FLP) controls the stomatal terminal division through transcriptional repression of the cell cycle genes CYCLIN-DEPENDENT KINASE (CDK) B1s (CDKB1s), CDKA; 1, and CYCLIN A2s (CYCA2s). We mutagenized the weak mutant allele flp-1 seeds with ethylmethane sulfonate and screened out a flp-1 suppressor 1 (fsp1) that suppressed the flp-1 stomatal cluster phenotype. FSP1 encodes RPA2a subunit of Replication Protein A (RPA) complexes that play important roles in DNA replication, recombination, and repair. Here, we show that FSP1/RPA2a functions together with CDKB1s and CYCA2s in restricting stomatal precursor proliferation, ensuring the stomatal terminal division and maintaining a normal guard-cell size and DNA content. Furthermore, we provide direct evidence for the existence of an evolutionarily conserved, but plant-specific, CDK-mediated RPA regulatory pathway. Serine-11 and Serine-21 at the N terminus of RPA2a are CDK phosphorylation target residues. The expression of the phosphorylation-mimic variant RPA2a(S11,21/D) partially complemented the defective cell division and DNA damage hypersensitivity in cdkb1;1 1;2 mutants. Thus, our study provides a mechanistic understanding of the CDK-mediated phosphorylation of RPA in the precise control of cell cycle and DNA repair in plants

A SiO J = 5 - 4 Survey Toward Massive Star Formation Regions

We performed a survey in the SiO $J=5\rightarrow4$ line toward a sample of 199 Galactic massive star-forming regions at different evolutionary stages with the SMT 10 m and CSO 10.4 m telescopes. The sample consists of 44 infrared dark clouds (IRDCs), 86 protostellar candidates, and 69 young \HII\ regions. We detected SiO $J=5\rightarrow4$ line emission in 102 sources, with a detection rate of 57\%, 37\%, and 65\% for IRDCs, protostellar candidates, and young \HII\ regions, respectively. We find both broad line with Full Widths at Zero Power (FWZP) $>$ 20 \kms and narrow line emissons of SiO in objects at various evolutionary stages, likely associated with high-velocity shocks and low-velocity shocks, respectively. The SiO luminosities do not show apparent differences among various evolutionary stages in our sample. We find no correlation between the SiO abundance and the luminosity-to-mass ratio, indicating that the SiO abundance does not vary significantly in regions at different evolutionary stages of star formation.Comment: 25 pages, 9 figures, 5 tables, accepted for publication in Ap

Micropore-Boosted Layered Double Hydroxide Catalysts：EIS Analysis in Structure and Activity for Effective Oxygen Evolution Reaction

Since the oxygen evolution catalysis process is vital yet arduous in energy conversion and storage devices, it is highly desirous but extremely challenging to engineer earth-abundant, noble-metal-free nanomaterials with superior electrocatalytic activity toward effective oxygen evolution reactions (OERs). Herein, we construct a prismlike cobalt–iron layered double hydroxide (Co–Fe LDH) with a Co/Fe ratio of 3:1 utilizing a facile self-templated strategy. Instead of carbon-species-coupled treatment, we focus on ameliorating the intrinsic properties of LDHs as OER electrocatalysts accompanied by the hierarchical nanoflake shell, well-defined interior cavity, and numerous microporous defects. In contrary to conventional LDHs synthesized via a one-pot method, Co–Fe LDHs fabricated in this work possess a huge specific surface area up to 294.1 m^2 g^(–1), which not only provides abundant active sites but also expedites the kinetics of the OER process. The as-prepared Co–Fe LDH electrocatalysts exhibit advanced electrocatalytic performance and a dramatic stability of the OER in an alkaline environment. In particular, the contribution of micropore defects is clearly discussed according to the electrochemical impedance spectroscopy analysis, in which the time constant of the OER at the micropore defect is several orders of magnitude smaller than that at the exterior of Co–Fe LDHs, forcefully verifying the intrinsic catalytic activity enhancement derived from the micropore defects. This work provides a promising model to improve OER electrocatalyst activity via produce defects and research the contribution of micropore defects

Urban–rural difference in the costs of disability and its effects on poverty among people with disabilities in China

The urban–rural difference in poverty is an important issue in China, particularly for people with disabilities. The extra costs of disability render this population susceptible to falling into poverty, where this can exacerbate the inequality among people with disabilities between urban and rural areas of the country. Previous studies have provided empirical evidence for the extra costs of disabilities in certain countries, but little scholarly attention has been devoted to the urban–rural gap in the costs of disability, particularly in countries like China that have a dual urban–rural system. This study explores changes in the extra costs of disability in China between urban and rural households with disabled members from 2008 to 2018 by using the standard of living approach. We apply the Foster–Greer–Thorbecke Poverty Index to measure the rates of poverty in urban and rural households with disabilities after considering the costs of disability. The results reveal that the costs of disability were not always lower for rural households than for urban households. At the same time, many rural households with disabled people were found to suffer from severe poverty owing to the high costs of their disabilities. The difference in health insurance and rehabilitation services between urban and rural China have led to an urban-rural gap in the costs of disability. This suggests that supplying more goods and services for disabled people in rural areas, especially free services, and raising the reimbursement due to them from their health insurance can help improve their standard of living

Millimeter Spectral Line Mapping Observations Toward Four Massive Star Forming HII Regions

We present spectral line mapping observations toward four massive star-forming regions (Cepheus A, DR21S, S76E and G34.26+0.15), with the IRAM 30 meter telescope at 2 mm and 3 mm bands. Totally 396 spectral lines from 51 molecules, one helium recombination line, ten hydrogen recombination lines, and 16 unidentified lines were detected in these four sources. An emission line of nitrosyl cyanide (ONCN, 14$_{0,14}$-13$_{0,13}$) was detected in G34.26+0.15, as first detection in massive star-forming regions. We found that the $c$-C$_{3}$H$_{2}$ and NH$_{2}$D show enhancement in shocked regions as suggested by evidences of SiO and/or SO emission. Column density and rotational temperature of CH$_{3}$CN were estimated with the rotational diagram method for all four sources. Isotope abundance ratios of $^{12}$C/$^{13}$C were derived using HC$_{3}$N and its $^{13}$C isotopologue, which were around 40 in all four massive star-forming regions and slightly lower than the local interstellar value ($\sim$65). $^{14}$N/$^{15}$N and $^{16}$O/$^{18}$O abundance ratios in these sources were also derived using double isotopic method, which were slightly lower than that in local interstellar medium. Except for Cep A, $^{33}$S/$^{34}$S ratio in the other three targets were derived, which were similar to that in the local interstellar medium. The column density ratios of N(DCN)/N(HCN) and N(DCO$^{+}$)/N(HCO$^{+}$) in these sources were more than two orders of magnitude higher than the elemental [D]/[H] ratio, which is 1.5$\times$10$^{-5}$. Our results show the later stage sources, G34.26+0.15 in particular, present more molecular species than earlier stage ones. Evidence of shock activity is seen in all stages studied.Comment: 32 pages, 11 figures, 8 tables, accepted for publication in MNRA