Reconstructed springtime (March–June) precipitation tracked by tree rings dating back to 1760 CE in the Qinling-Bashan mountainous area

In recent decades, considerable advances have been made in dendroclimatic reconstruction in the eastern monsoon region of China. However, understanding of long-term hydroclimatic changes has not been comprehensive due to the complexity of the regional geography in China's north-south transitional zone. Growth-climate response analysis indicated that springtime precipitation is the main factor limiting the radial growth of pine trees in the Qinling-Bashan mountainous area. Based on the three tree ring chronologies distributed in the southeast of Shaanxi Province, we developed a March–June precipitation reconstruction spanning 1760–2020 CE for the Qinling-Bashan mountainous area. Precipitation reconstruction accounts for 40.6% of the total precipitation variance during the instrumental period 1955–2016. Spatial correlation analysis indicated that the precipitation reconstruction recorded similar common precipitation signals for the eastern Qinling Mountains and the Yangtze-Huai River Basin. The results of the superposed epoch analysis (SEA) revealed that low precipitation was one of the main causes of severe drought and locust plague events. The preliminary synoptic climatology analysis showed that our reconstructed precipitation is closely linked to the El Niño-Southern Oscillation (ENSO) and Indian Ocean Dipole (IOD) variability.Fil: Wang, Shijie. Yunnan University; ChinaFil: Man, Wenmin. Chinese Academy of Sciences; República de ChinaFil: Chen, Feng. Yunnan University; China. China Meteorological Administration; ChinaFil: Chen, Youping. Yunnan University; ChinaFil: Yu, Shulong. China Meteorological Administration; ChinaFil: Cao, Honghua. Yunnan University; ChinaFil: Hu, Mao. Yunnan University; ChinaFil: Hou, Tiyuan. Yunnan University; ChinaFil: Hadad, Martín Ariel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Juan. Centro de Investigaciones de la Geosfera y Biosfera. Universidad Nacional de San Juan. Facultad de Ciencias Exactas Físicas y Naturales. Centro de Investigaciones de la Geosfera y Biosfera; ArgentinaFil: Roig Junent, Fidel Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Provincia de Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Universidad Nacional de Cuyo. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales; Argentina. Universidad Mayor; Chil

配位結合により塩基対を形成する人工カテコール型ヌクレオシドの合成と機能化

　　Biomacromolecules such as protein and nucleic acid are excellent functional molecules, which play crutial roles in the vital functions in biological system in an accurate and well-controlled manner. Owing to recent developments in organic synthesis and biotechnology, it has become feasible to chemically modify these molecular structures at the molecular level. 　　An alternative approach she has used for the reconstruction of DNA is the direct modification of nucleobases by incorporating metal-chelating nucleobases into DNA strands. In this artificial DNA, hydrogen-bonded base pairing is replaced by metal-induced base pairing, thereby creating a novel hybridization motif in double-stranded DNA (Chart 1). (Chart 1 was abbreviated.) She has synthesized an artificial β-C-nucleoside 6 which have a catechol group as a nucleobase. This novel nucleoside was synthesized from a 2\u27-deoxyribose derivartive 1 and О-protected catechol 2 via Friedel-Crafts coupling reaction to selectively afford the desired product β-C-nucleoside 4 in 36% yield. The following two-step deprotection procedures afforded the target β-C-nucleoside 6 (Scheme 1).(Scheme 1 was abbreviated.) Catechol-bearing β-C-nucleoside 6 was treated with half amount of trimethyl borate and triethylamine in DMSO-d6, at room temperature to obtain 2:1 complex 7 between nucleosides and boron (III) (Scheme 2). (Scheme 2 was abbreviated.)The isotopically resolved ESI-TOF mass spectrum of this solution in the negative mode provided clear evidence for the 2:1 complexation between 6 and boron ion. The singnal at m/z 459.15 [7-Et3NH+]- gave excellent agreement between the experimental and theoretical isotopic distributions indicating the boron-assisted dimerization of 6. 500 MHz 1H NMR resonances from aromatic protons of the complex 7 in DMSO-d6 were upfield-shifted from those of the nucleoside 6, and the signals for hydroxy protons on the catechol moiety disappeared upon complexation, whereas those for the ribose moity still remained. These results indicate that phenoxy groups coordinated to the boron (III) center, in the deprotonated form, that is to say a boron (III) ion promoted base pairing of 6. Although there are two possible diastereomeric structures for the complex 7, they only observed one set of proton signals for the complex 7 in the spectrum. She then tried to incorporate a catechol-type β-C-nucleoside as a "chelator- nucleoside" building block into a DNA strand by means of a phosphotriester or a phosphoramidite approach. She synthesized phosphoramidite type 10 and phosphotriester-type 12 and 13, starting from compound 9 (Scheme 3), which can be used to introduce the catechol-type nucleoside into oligo- DNA. (Scheme 3 was abbreviated.) This work demonstrates a novel base pairing mode assisted by borate formation, which would provide an alternative DNA base pair in addition to other metal-assisted base pairs that have been developed in our group so far. This novel base pair at specific site of oligo-DNA would contribute to the development of new structural and functionalized super-biomolecules

FBXL5 Inhibits Metastasis of Gastric Cancer Through Suppressing Snail1

Background/Aims: The Snail family of transcription factors controls epithelial to mesenchymal transition (EMT), a process associated with tumorigenesis originated from epithelial cells. Snail1 is a member from Snail family and upregulation of Snail1 has been detected in gastric cancer (GC), suggesting a potential role of Snail1 in GC metastasis. We have recently reported that FBXL5 regulates cortactin by inducing its ubiquitylation and subsequent proteasomal degradation, resulting in inhibition of metastasis of GC. However, a role of FBXL4 in regulation of other EMT-associated proteins is not unknown. Methods: The levels of FBXL5 and Snail1 as well as their relationship were determined in GC specimen. Co-immunoprecipitation (IP) was performed to detect the interaction between Snail1 and FBXL5 in GC cells. The effects on Snail1 by FBXL5 were examined by overexpression of depletion of FBXL5 in GC cells. The invasiveness of the FBXL5-modified GC cells was examined in both scratch wound healing assay and transwell matrix penetration assay. Results: FBXL5 also physiologically interacted with Snail1. FBXL5 inhibited Snail1 to suppress GC cell invasiveness. Conclusion: FBXL5 negatively regulates several EMT-enhancing factors. FBXL5 is an attractive novel target for inhibiting invasion and metastasis of GC cells

Research on the Transport of Typical Pollutants in the Yellow Sea with Flow and Wind Fields

In this study, we developed a transport model for typical pollutants in the Yellow Sea using the Lagrangian particle tracking method to analyze the trajectories of fish feed, a common pollutant in the Yellow Sea. The model incorporates the influence of ocean currents and surface winds on pollutant transport and utilizes a series of numerical experiments to simulate pollutant transport. Through statistical analysis of the numerical experiment results, we identified characteristic circles that represent the pollutant distribution patterns. Furthermore, based on the current and wind information within these characteristic circles, we derived an empirical formula to describe pollutant distribution. This formula enables us to predict the spatial distribution of pollutants using available current and wind data. Using this empirical formula, we designed an effective path to avoid pollutant contamination. This approach not only optimizes the utilization of computational resources within the study area but also contributes to the rational planning of navigation routes for aquaculture vessels. Overall, our study provides valuable insights into the transport behavior of fish feed pollutants in the Yellow Sea. The establishment of the empirical formula and the design of effective routes to avoid pollution contribute to the efficient management of pollution and facilitate the planning of marine activities in the region

Three-Dimensional IFE-PIC Numerical Simulation of Background Pressure\u27s Effect on Accelerator Grid Impingement Current for Ion Optics

A three-dimensional numerical simulation modeling is developed to investigate the background pressure\u27s effect on the characteristics of ion impingement on the accelerator grid for the ion optical system. The immersed-finite-element particle-in-cell (IFE-PIC) method is combined with Monte Carlo method to compute the electric field, track the ions, and describe the charge-exchange collision process while direct simulation Monte Carlo (DSMC) method is adopted to simulate the motion of neutral atoms. Results show that the residual neutral atoms in the vacuum chamber play an important role in the neutral atoms distribution when the background pressure is higher than a specific magnitude, and the accelerator grid impingement current increases with the increase of the background pressure. To improve the reliability of ion thruster service lifetime prediction in the ground life tests, the background pressure in the vacuum chamber should be below 10-3 Pa