42 research outputs found
Spatial variation in grain-size population of surface sediments from northern Bering Sea and western Arctic Ocean: implications for provenance and depositional mechanisms
In general, sediments in nature comprise populations of various diameters. Accurate information regarding the sources and depositional mechanisms of the populations can be obtained through their temporal and spatial comparisons. In this study, the grain size distribution of surface sediments from the Bering Sea and western Arctic Ocean were fitted and partitioned into populations using a log-normal distribution function. The spatial variations in the populations indicate differences in their sources and deposition mechanisms. The sediments on most of the Bering Sea Shelf originated from the Yukon River, and were transported westward by waves and currents. However, the presence of a coarser population outside Anadyr Bay was the result of Anadyr River transport. Additionally, a northward transport trend of fine suspended particles was observed on the west side of the Bering Sea Shelf. The sediments in Hope Valley in the south Chukchi Sea also originated from the Yukon River. The coarser population on the central Chukchi Sea Shelf originated from coast of Alaska to the east, not the Yukon River, and was transported by sea ice and bottom brine water. The populations of sediments from the Chukchi Basin and the base of the Chukchi Sea Slope are the result of sea ice and eddy action. Surface sediments from the western high Arctic Ocean predominantly comprised five populations, and two unique populations with mode diameters of 50–90 μm and 200–400 μm, respectively, were ubiquitous in the glacial and interglacial sediments. It was difficult to distinguish whether these two populations originated from sea ice or icebergs. Therefore, caution should be exercised when using either the > 63 μm or > 250 μm fractions in sediments as a proxy index for iceberg and ice sheet variation in the high Arctic Ocean
Transcriptional Regulation of PP2A-Aα Is Mediated by Multiple Factors Including AP-2α, CREB, ETS-1, and SP-1
Protein phosphatases-2A (PP-2A) is a major serine/threonine phosphatase and accounts for more than 50% serine/threonine phosphatase activity in eukaryotes. The holoenzyme of PP-2A consists of the scaffold A subunit, the catalytic C subunit and the regulatory B subunit. The scaffold subunits, PP2A-Aα/β, provide a platform for both C and B subunits to bind, thus playing a crucial role in providing specific PP-2A activity. Mutation of the two genes encoding PP2A-Aα/β leads to carcinogenesis and likely other human diseases. Regulation of these genes by various factors, both extracellular and intracellular, remains largely unknown. In the present study, we have conducted functional dissection of the promoter of the mouse PP2A-Aα gene. Our results demonstrate that the proximal promoter of the mouse PP2A-Aα gene contains numerous cis-elements for the binding of CREB, ETS-1, AP-2α, SP-1 besides the putative TFIIB binding site (BRE) and the downstream promoter element (DPE). Gel mobility shifting assays revealed that CREB, ETS-1, AP-2α, and SP-1 all bind to PP2A-Aα gene promoter. In vitro mutagenesis and reporter gene activity assays reveal that while SP-1 displays negative regulation, CREB, ETS-1 and AP-2Aα all positively regulate the promoter of the PP2A-Aα gene. ChIP assays further confirm that all the above transcription factors participate the regulation of PP2A-Aα gene promoter. Together, our results reveal that multiple transcription factors regulate the PP2A-Aα gene
Energy Demand and Carbon Emission Peak Paths for the Rise of Central China
Energy revolution is essential for the coordinated and sustainable development of economy, society, and the environment, and it should coordinate with regional development strategies. Using the Kaya identity, this study categorizes the energy consumption demand brought by the rise of Central China into production and living demand. Energy demand scenarios for the rise of Central China are constructed considering factors such as gross domestic product, industrial structure, urbanization, energy efficiency, per capita income, and residential energy. Accordingly, the low-carbon development paths under energy revolution are analyzed. Urbanization and industrialization will promote the total energy demand in the five provinces in Central China up to 8.4×108–1.01×109 tce in 2035. Moreover, the establishment of a diversified energy supply system can help achieve low-carbon emission, energy security, and efficient utilization of energy; a carbon emission peak is expected to reach before 2030. China should vigorously develop technologies regarding energy conservation and clean and renewable energies. A multi-energy complementary system should be established in China by optimizing the industrial structure, and the existing energy system should be reformed to realize energy cooperation among regions
Self-powered MSM deep-ultraviolet beta-Ga2O3 photodetector realized by an asymmetrical pair of Schottky contacts
Self-powered photodetectors working in solar-blind region (below 280 nm) have attracted growing attention due to their wide applicability. Monoclinic Ga2O3 (beta-Ga2O3) with excellent merits and a wide bandgap (4.9 eV) is regarded as a good candidate for solar-blind photodetector application. Self-powered photodetectors generally based on homo/heterojunction suffer from a complex fabrication process and slow photoresponse because of the interface defects and traps. Herein, we demonstrated a fabrication and characterization of a self-powered metal-semiconductor-metal (MSM) deep-ultraviolet (DUV) photodetector based on single crystal beta-Ga2O3 . The self-powered property was realized through a simple one-step deposition of an asymmetrical pair of Schottky interdigital contacts. The photocurrent and responsivity increase with the degenerating symmetrical contact. For the device with the most asymmetric interdigital contacts operated at 0 V bias, the maximum photocurrent reaches 2.7 nA. The responsivity R-lambda. external quantum efficiency EQE, detectivity D*, and linear dynamic range LDR are 1.28 mA/W, 0.63, 1.77 x 10(11) Jones, and 23.5 dB, respectively. The device exhibits excellent repeatability and stability at the same time. Besides, the device presents a fast response speed with a rise time of 0.03 s and a decay time of 0.08 s. All these results indicate a promising and simple method to fabricate a zero-powered DUV photodetector. (C) 2019 Optical Society of America under the terms of the OSA Open Access Publishing AgreementFunding Agencies|Natural Science Foundation of China [51711530035, 61874084, 61704125]; Swedish Foundation for International Cooperation in Research and Higher Education (STINT) [CH2016-6722]</p
A Fusion–Growth Protocell Model Based on Vesicle Interactions with Pyrite Particles
Protocell models play a pivotal role in the exploration of the origin of life. Vesicles are one type of protocell model that have attracted much attention. Simple single-chain amphiphiles (SACs) and organic small molecules (OSMs) possess primitive relevance and were most likely the building blocks of protocells on the early Earth. OSM@SAC vesicles have been considered to be plausible protocell models. Pyrite (FeS2), a mineral with primitive relevance, is ubiquitous in nature and plays a crucial role in the exploration of the origin of life in the mineral–water interface scenario. “How do protocell models based on OSM@SAC vesicles interact with a mineral–water interface scenario that simulates a primitive Earth environment” remains an unresolved question. Hence, we select primitive relevant sodium monododecyl phosphate (SDP), isopentenol (IPN) and pyrite (FeS2) mineral particles to build a protocell model. The model investigates the basic physical and chemical properties of FeS2 particles and reveals the effects of the size, content and duration of interaction of FeS2 particles on IPN@SDP vesicles. This deepens the understanding of protocell growth mechanisms in scenarios of mineral–water interfaces in primitive Earth environments and provides new information for the exploration of the origin of life
Plasma versican and plasma exosomal versican as potential diagnostic markers for non-small cell lung cancer
Abstract Background and aims This study aimed to investigate the expression of plasma versican and plasma exosomal versican in non-small cell lung cancer (NSCLC) and its correlation with clinicopathological features, and to evaluate its diagnostic performance in NSCLC and its predictive function for NSCLC incidence and metastasis risk. Materials and methods There were 110 instances of NSCLC, 42 cases of benign lung disease, and 55 healthy controls from September 2018 to October 2020 at Tongji Hospital Affiliated to Tongji University. Blood was collected and plasma was separated before surgery, and plasma exosomes were extracted by ExoQuick kit. Morphological and molecular phenotype identification of exosomes was performed by transmission electron microscopy, Nanosight particle tracking analysis, and western blotting. Plasma versican and plasma exosomal versican were detected in all subjects to assess their expression levels and diagnostic value in NSCLC. Clinicopathological data were collected to explore correlations between abnormal plasma versican and plasma exosomal versican expression and clinicopathological parameters. Receiver operating characteristic (ROC) curve was used to judge its diagnostic performance in NSCLC, and binary logistic regression analysis was used to predict the risk of NSCLC incidence and metastasis. Results Plasma versican and plasma exosomal versican expression in NSCLC patients was significantly upregulated and was significantly higher in T3 + T4 patients compared with T1 + T2 patients (P < 0.05); the levels of plasma versican and plasma exosomal versican were positively correlated with lymph node metastasis, distant metastases (e.g., brain, bone), and mutation(e.g., EGFR,ALK)in NSCLC patients (all P < 0.05). Furthermore, ROC curve analysis showed that plasma versican and plasma exosomal versican had higher AUC values than NSE, CYFRA21-1, and SCC, and better diagnostic performance in NSCLC patients. However, the AUC and diagnostic performances of plasma versican and plasma exosomal versican in advanced-stage NSCLC patients were not shown to be significantly better than CEA. The results of binary logistic regression analysis showed that high levels of plasma exosomal versican had higher predictive value for lung cancer incidence, while high levels of plasma versican had higher predictive value for lung cancer metastasis. Conclusion Our findings showed that plasma versican and plasma exosomal versican might be potential diagnostic markers for NSCLC. High plasma exosomal versican expression can be used as a predictor of NSCLC risk and high plasma versican expression can be used as a predictor of NSCLC metastasis risk