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Distortion of the water cycle, particularly of its extremes (droughts and pluvials), will be among the most conspicuous consequences of climate change. We applied a novel approach with terrestrial water storage observations from the GRACE and GRACE-FO satellites to delineate and characterize 1,056 extreme events during 2002-2021. Dwarfing all other events was an ongoing pluvial that began in 2019 and engulfed central Africa. Total intensity of extreme events was strongly correlated with global mean temperature, more so than with the El Nino Southern Oscillation or other climate indicators, suggesting that continued warming of the planet will cause more frequent, more severe, longer, and/or larger droughts and pluvials. In three regions, including a vast swath extending from southern Europe to southwestern China, the ratio of wet to dry extreme events decreased substantially over the study period, while the opposite was true in two regions, including sub-Saharan Africa from 5°N to 20°N.

Van der Waals heterostructures (vdWHs) have attracted tremendous interest owing to the ability to assemble diverse building blocks without the constraints of lattice matching and processing compatibility. However, once assembled, the fabricated vdWHs can hardly be separated into individual building blocks for further manipulation, mainly due to technical difficulties in the disassembling process. Here, we show a method to disassemble the as-fabricated vdWHs into individual building blocks, which can be further reassembled into new vdWHs with different device functionalities. With this technique, we demonstrate reconfigurable transistors from n-type to p-type and back-gate to dual-gate structures through re-stacking. Furthermore, reconfigurable device behaviors from floating gate memory to Schottky diode and reconfigurable anisotropic Raman behaviors have been obtained through layer re-sequencing and re-twisting, respectively. Our results could lead to a reverse engineering concept of disassembled vdWHs electronics in parallel with state-of-the-art vdWHs electronics, offering a general method for multi-functional pluggable electronics and optoelectronics with limited material building blocks. Here, the authors report a method to fabricate reconfigurable electronic devices based on 2D materials by using polyvinyl alcohol as substrate. This technique enables repeatable disassembling and reassembling of van der Waals heterostructures with different functionalities.

This study examined long-term, natural (i.e., excluding anthropogenic impacts) variability of groundwater storage worldwide. Groundwater storage changes were estimated by forcing three global-scale hydrological models with three 50+ year meteorological datasets. Evaluation using in situ groundwater observations from the U.S. and terrestrial water storage derived from the Gravity Recovery and Climate Experiment (GRACE) satellites showed that these models reasonably represented inter-annual variability of water storage, as indicated by correlations greater than 0.5 in most regions. Empirical orthogonal function analysis revealed influences of the El Niño Southern Oscillation (ENSO) on global groundwater storage. Simulated groundwater storage, including its global average, exhibited trends generally consistent with that of precipitation. Global total (natural) groundwater storage decreased over the past 5-7 decades with modeled rates ranging from 0.01 to 2.18 mm year-1. This large range can be attributed in part to groundwater’s low frequency (inter-decadal) variability, which complicates identification of real long-term trends even within a 50+ year time series. Results indicate that non-anthropogenic variability in groundwater storage is substantial, making knowledge of it fundamental to quantifying direct human impacts on groundwater storage.

Two-dimensional (2D) materials 1 , 2 and the associated van der Waals (vdW) heterostructures 3 – 7 have provided great flexibility for integrating distinct atomic layers beyond the traditional limits of lattice-matching requirements, through layer-by-layer mechanical restacking or sequential synthesis. However, the 2D vdW heterostructures explored so far have been usually limited to relatively simple heterostructures with a small number of blocks 8 – 18 . The preparation of high-order vdW superlattices with larger number of alternating units is exponentially more difficult, owing to the limited yield and material damage associated with each sequential restacking or synthesis step 8 – 29 . Here we report a straightforward approach to realizing high-order vdW superlattices by rolling up vdW heterostructures. We show that a capillary-force-driven rolling-up process can be used to delaminate synthetic SnS 2 /WSe 2 vdW heterostructures from the growth substrate and produce SnS 2 /WSe 2 roll-ups with alternating monolayers of WSe 2 and SnS 2 , thus forming high-order SnS 2 /WSe 2 vdW superlattices. The formation of these superlattices modulates the electronic band structure and the dimensionality, resulting in a transition of the transport characteristics from semiconducting to metallic, from 2D to one-dimensional (1D), with an angle-dependent linear magnetoresistance. This strategy can be extended to create diverse 2D/2D vdW superlattices, more complex 2D/2D/2D vdW superlattices, and beyond-2D materials, including three-dimensional (3D) thin-film materials and 1D nanowires, to generate mixed-dimensional vdW superlattices, such as 3D/2D, 3D/2D/2D, 1D/2D and 1D/3D/2D vdW superlattices. This study demonstrates a general approach to producing high-order vdW superlattices with widely variable material compositions, dimensions, chirality and topology, and defines a rich material platform for both fundamental studies and technological applications. A simple but flexible technique based on a capillary-force-driven rolling-up process produces high-order van der Waals superlattices that are hard to produce with existing fabrication techniques.

Most of the current methods for the synthesis of two-dimensional materials (2DMs) require temperatures not compatible with traditional back-end-of-line (BEOL) processes in semiconductor industry (450 °C). Here, we report a general BiOCl-assisted chemical vapor deposition (CVD) approach for the low-temperature synthesis of 27 ultrathin 2DMs. In particular, by mixing BiOCl with selected metal powders to produce volatile intermediates, we show that ultrathin 2DMs can be produced at 280–500 °C, which are ~200–300 °C lower than the temperatures required for salt-assisted CVD processes. In-depth characterizations and theoretical calculations reveal the low-temperature processes promoting 2D growth and the oxygen-inhibited synthetic mechanism ensuring the formation of ultrathin nonlayered 2DMs. We demonstrate that the resulting 2DMs exhibit electrical, magnetic and optoelectronic properties comparable to those of 2DMs grown at much higher temperatures. The general low-temperature preparation of ultrathin 2DMs defines a rich material platform for exploring exotic physics and facile BEOL integration in semiconductor industry. Chemical vapor deposition (CVD) is a versatile method to synthesize 2D materials, but usually requires high growth temperatures. Here, the authors report a BiOCl-assisted CVD approach to grow 2D nanosheets from 27 different layered and nonlayered materials at temperatures <500 °C, which are compatible with back-end-of-the-line industrial processes.

Palladium diselenide (PdSe 2 ), a stable layered material with pentagonal structure, has attracted extensive interest due to its excellent electrical and optoelectronic performance. Here, we report a reliable process to synthesize PdSe 2 via chemical vapor deposition (CVD) method. Through systematic regulation of temperature in the growth process, we can tune the thickness, size, nucleation density and morphology of PdSe 2 nanosheets. Field-effect transistors based on PdSe 2 nanosheets exhibit n-type behavior and present a high electron mobility of 105 cm 2 ·V −1 ·s −1 . The electrical property of the devices after 6 months keeping in the air show little change, implying outstanding air-stability of PdSe 2 . In addition, PdSe 2 near-infrared photodetector shows a photoresponsivity of 660 A·W −1 under 914 nm laser. These performances are better than those of most CVD-grown 2D materials, making ultrathin PdSe 2 a highly qualified candidate material for next-generation optoelectronic applications.

The Gravity Recovery and Climate Experiment (GRACE) twin satellites observe time variations in Earth's gravity field which yield valuable information about changes in terrestrial water storage (TWS). GRACE is characterized by low spatial (>150,000 km2) and temporal (>10 days) resolution but has the unique ability to sense water stored at all levels (including groundwater) systematically and continuously. The GRACE Data Assimilation System (DAS), based on the Catchment Land Surface Model (CLSM), enhances the value of the GRACE water storage data by enabling spatial and temporal downscaling and vertical decomposition into moisture components (i.e., groundwater, soil moisture, and snow), which individually are more useful for scientific applications. In this study, GRACE DAS was applied to North America, and GRACE‐based drought indicators were developed as part of a larger effort to investigate the possibility of more comprehensive and objective identification of drought conditions by integrating spatially, temporally, and vertically disaggregated GRACE data into the U.S. and North American Drought Monitors. Previously, the drought monitors lacked objective information on deep soil moisture and groundwater conditions, which are useful indicators of drought. Extensive data sets of groundwater storage from U.S. Geological Survey monitoring wells and soil moisture from the Soil Climate Analysis Network were used to assess improvements in the hydrological modeling skill resulting from the assimilation of GRACE TWS data. The results point toward modest, but statistically significant, improvements in the hydrological modeling skill across major parts of the United States, highlighting the potential value of a GRACE‐assimilated water storage field for improving drought detection. Key Points GRACE has the unique ability to sense water stored at all levels Data assimilation is required to realize the full potential of GRACE Highlights the potential value of GRACE data for drought detection purposes

The tunable properties of halide perovskite/two dimensional (2D) semiconductor mixed-dimensional van der Waals heterostructures offer high flexibility for innovating optoelectronic and photonic devices. However, the general and robust growth of high-quality monocrystalline halide perovskite/2D semiconductor heterostructures with attractive optical properties has remained challenging. Here, we demonstrate a universal van der Waals heteroepitaxy strategy to synthesize a library of facet-specific single-crystalline halide perovskite/2D semiconductor (multi)heterostructures. The obtained heterostructures can be broadly tailored by selecting the coupling layer of interest, and can include perovskites varying from all-inorganic to organic-inorganic hybrid counterparts, individual transition metal dichalcogenides or 2D heterojunctions. The CsPbI 2 Br/WSe 2 heterostructures demonstrate ultrahigh optical gain coefficient, reduced gain threshold and prolonged gain lifetime, which are attributed to the reduced energetic disorder. Accordingly, the self-organized halide perovskite/2D semiconductor heterostructure lasers show highly reproducible single-mode lasing with largely reduced lasing threshold and improved stability. Our findings provide a high-quality and versatile material platform for probing unique optoelectronic and photonic physics and developing further electrically driven on-chip lasers, nanophotonic devices and electronic-photonic integrated systems. Halide perovskite/2D transition metal dichalcogenides (TMD) heterostructures hold promise for photonic/optoelectronic applications, but their bottom-up growth remains challenging. Here, the authors report a van der Waals heteroepitaxy strategy to synthesize various halide perovskite/TMD heterostructures with enhanced lasing performance.

Background MicroRNAs (miRNAs) are small noncoding RNAs that post-transcriptional regulate gene expression in a variety of cancers. Increasing evidences indicate that miR-30 expression is down-regulated in numerous human cancers including non-small cell lung cancer (NSCLC) which hypothesizes that miR-30 may play an important role in tumorigenesis. The aim of this study was to investigate the target gene of miR-30 and its roles in tumor growth of NSCLC. Methods Luciferase reporter assays were employed to validate regulation of a putative target of miR-30. The effect of miR-30 on endogenous levels of this target were subsequently confirmed via Western blot (WB). Quantitative reverse transcription-polymerase chain reaction (qRT-PCR) was performed to determine the expression level of miR-30 in NSCLC specimens and adjacent non-tumor tissues. MTT assays were conducted to explore the impact of miR-30 overexpression on the proliferation of human NSCLC cells. Results Both miR-30b and miR-30c (miR-30b/c) were found having target site in same region of Rab18 mRNA. Luciferase assays using a reporter carrying a putative miR-30b/c target site in the coding DNA sequence (CDS) region of Rab18 revealed that miR-30b/c directly targeted Rab18. Overexpression of miR-30b/c led to down-regulation of Rab18 in A549 and H23 cells at protein levels but not mRNA levels. Down-regulation of miR-30b/c and up-regulation of Rab18 protein levels were detected in NSCLC specimens compared with adjacent non-tumor tissues. Overexpression of miR-30b/c suppressed NSCLC cells growth. Knockdown of Rab18 by siRNA significantly inhibited the proliferation of NSCLC cells. Conclusions We demonstrated that miR-30b/c was down-regulated in NSCLC specimens compared with adjacent non-tumor tissues. miR-30b/c directly targeted and down-regulated Rab18 expression and inhibited NSCLC cells proliferation. These data indicated that miR-30b/c could serve as a tumor suppressor gene involved in NSCLC pathogenesis.

Glucagon-like peptide 1 (GLP-1) is a peptide hormone that is released from the gut in response to nutrient ingestion and that has a range of metabolic effects, including enhancing insulin secretion and decreasing food intake. Postprandial GLP-1 secretion is greatly enhanced in rats and humans after some bariatric procedures, including vertical sleeve gastrectomy (VSG), and has been widely hypothesized to contribute to reduced intake, weight loss, and the improvements in glucose homeostasis after VSG. We tested this hypothesis using two separate models of GLP-1 receptor deficiency. We found that VSG-operated GLP-1 receptor–deficient mice responded similarly to wild-type controls in terms of body weight and body fat loss, improved glucose tolerance, food intake reduction, and altered food selection. These data demonstrate that GLP-1 receptor activity is not necessary for the metabolic improvements induced by VSG surgery.