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The vertical distribution of suspended sediment concentration (SSC) plays a key role in the residual suspended sediment transport in the estuarine environments. A field measurement was carried out in the turbidity maximum zone (TMZ) of the Changjiang Estuary in 2012 to study the characteristics and formation mechanisms of SSC profile in the partially stratified estuary. Based on the observed data, we found that the vertical distribution of SSCs is mainly determined by the density stratification caused by the interactions between the river runoff and the saltwater intrusion. The vertical profiles of SSC were categorized into three types: (I) two-layer structure profile, (II) exponential profile, and (III) linear profile. Type I mainly occurred in condition of strong stratification, whereas types II and III mainly occurred in weak stratification and well-mixed conditions, respectively. We developed two new empirical equations to simulate the vertical profiles, which can accurately describe the observed exponential and linear profiles and reasonably/accurately describe the observed two-layer structure profiles. The two new equations can be easily used in other well-mixed or partially stratified estuaries given the surface and bottom SSC data, which can be obtained from many ways, for instance, the buoy and bottom tripod survey system, the remote-sensed images, and numerical models. [ABSTRACT FROM AUTHOR]

Cognitive impairment of cerebral small vessel disease (CSVD) is one of the most common cognitive disorders. It has a high incidence and results in heavy social burden; thus, it is essential to provide reasonable diagnosis and treatment in clinical practice. Based on the results of clinical research and related reports, combined with the actual situation in China, we propose a diagnosis and treatment guideline for cognitive impairment of CSVD. [ABSTRACT FROM AUTHOR]

Polymer waterproof coatings mainly include polymer cement waterproof coating and polymer emulsion waterproof coating. The effects of VAE and acrylic acid emulsion waterproof coating types on water absorption mechanical properties water resistanceheat treatment and aging resistance were studied in this article. The results showed that the VAE polymer cement waterproof coating have outstanding performance in water immersion and heat treatment the Polymer emulsion acrylic acid waterproof coating has excellEnt performance in aging resistance. It provides a theoretical basis for selecting suitable waterproof coatings in practical application. [ABSTRACT FROM AUTHOR]

Abstract Many rivers are facing human-induced system regime shifts that have great environmental, ecological and social implications, necessitating an increasing need to quantify the human influence on sediment properties and their impacts on the source-to-sink system of marginal seas. The Huanghe and Changjiang Rivers have experienced a dramatic reduction in sediment flux in recent decades, typifying the human influence on sediment properties of global large rivers. Sediment samples from the two rivers were analyzed to obtain grain size, magnetic and geochemical data. The results show a large difference in sediment properties between pre- and post-dam periods. We applied a discrepancy factor to re-examine the magnetic and geochemical tracers that were previously used in the two rivers. The discrepancy factors of most magnetic and geochemical tracers in the mud-sized sediments of the two rivers increased by an average of about 109% after dam construction. This suggests that human-induced changes in sediment properties have greatly improved the discriminatory ability between the sediments from the two rivers. The results also raise the uncertainty of using previous tracers to distinguish between sediments from the two rivers after damming. Furthermore, significant changes in sediment properties that happened in a relatively short time may provide future geological time markers for sedimentary records with a temporal resolution of 100–101 years. For marine environments, an approach for identifying sediment sources based on multiple independent optimum tracers is also proposed, with composite magnetic (SIRM vs. HIRM) and geochemical (Na 2 O vs. Zn) tracers being considered. The results of this work can advance our knowledge of how human activities alter river systems, and identify a sustainable development model under system regime shifts for areas of high-intensity human activity. Graphical abstract Unlabelled Image Highlights • Large differences in sediment properties exist between pre- and post-dam periods. • An approach of using multiple independent optimum tracers is proposed. • Human activities increased the differences between the sediments from the two rivers. • Amplified endmember differences may provide a future geological time marker. [ABSTRACT FROM AUTHOR]

Space gravitational wave detection is one of the most critical techniques that maintain high stability of the laser link to reduce the coupling of ranging noise. We model and simulate the laser pointing jitter noise of the laser link between two satellites and build an experimental system for testing. We adopt an FFT-based method for Monte Carlo generation of a random noise time-series signal with a prescribed power spectral density. This experimental system with noise inputs can be simulated in a way that is more consistent with the actual operation of the satellite in space. The experimental results show that laser pointing jitter noise mainly comes from the jitter of the satellite platform. In the 1 mHz to 1 Hz band, laser pointing jitter noise is an order of magnitude higher in the space environment than in the laboratory environment. However, the pointing system can still suppress the laser pointing jitter noise to the noise floor. [ABSTRACT FROM AUTHOR]

Suspended sediment concentration (SSC) has a significant impact on the estuarine environment and its morphological evolution. At any given location, the temporal variability of depth-averaged SSC is due to a combination of two processes: horizontal advection and local resuspension. In this study, we investigated the sediment dynamics at three anchored monitoring stations close to the maximum turbidity zone of the Changjiang Estuary, and developed a box model to differentiate the effects of advection and resuspension. Further, settling velocities were estimated using the ADV Reynolds flux method, excluding the advection SSC component. We found that predicted changes in advection- and resuspension-induced SSCs were consistent with the bottom shear stress and accretion/erosion observations. The combination of observed bed accretion/erosion changes and the predicted advection-induced SSCs indicates that the advective transport of suspended sediment is an important process in accelerating persistent erosion at the monitoring stations. Although SSC variations due to advection and resuspension are of similar magnitudes, our model results indicate that if resuspension dominates, the resuspension-induced component can reach up to twice the magnitude of the advection-induced component. We conclude that the box model is a valuable tool for evaluating subaqueous delta accretion/erosion in response to sediment reduction caused by upstream dam construction and climate change. [ABSTRACT FROM AUTHOR]

Mega-deltas are major sinks of river-borne sediments and important sources of terrigenous sediments for open shelves. Their evolution has far-reaching impacts on adjacent coastal waters, from the point of view of along-shelf morphodynamics and biogeochemistry. However, the complex budgeting patterns of input, storage, bypass, and final accumulation of sediment are still poorly understood. The Changjiang (Yangtze River) in China is among the world's largest river systems, not only in terms of water and sediment discharges but also the massive amount of sediment deposited in its subaqueous delta and distal muds. Here we discuss about the along-shelf sediment redistribution in the Changjiang Subaqueous Delta and Distal Muds (CSDDM) over the last century. For the purpose of understanding its spatial diversity in detail, we divided the study area into three spatially connected parts, namely the Changjiang subaqueous deltaic mud (CJM), the Zhejiang inner-shelf mud (ZJM), and the Fujian inner-shelf mud (FJM). The concept of sediment retention index helps understand the overall evolution of this mega-delta. Hydrological survey data from the peripheral rivers and short marine-sediment cores are used to evaluate the amount of sediment supplied to and deposited in the study area. The results show that over the last century, the rate of sediment supply to the CSDDM reached ~645 Mt year −1 on average (ranging between 535 and 725 Mt year −1 ), while the total sediment deposition in the CSDDM reached ~683 Mt year −1 on average (390–976 Mt year −1 ), with the ratio for the deposits in the CJM, ZJM and FJM being close to 3:5:2. As such, the input and output of sediment were generally in balance. The sediment retention indices are estimated to be 0.35, 0.86 and 1.00 for CJM, ZJM and FJM, respectively. This study contributes to our knowledge of marine sediment fluxes, facilitates a better understanding of the growth and development of mega-deltas under system regime shifts, and helps identify a sustainable development model for areas of high population density, heavy economic activity and rapid urbanization. [ABSTRACT FROM AUTHOR]

The radionuclide 210Pb is suitable for century-scale dating and has been used to calculate the sedimentation rate in a variety of environments. However, two common ways to apply 210Pb dating techniques may give misleading results. One is “prolonging of age”, i.e., using the calculated sedimentation rate to date back to 200 or 300 years. This practice must be treated with caution because the 210Pb dating techniques do not guarantee direct dating for ages much older than 100 years. Another is “loss of age”, i.e., the calculated time span between the topmost layer and the 210Pb background layer in cores is less than 100 years when an apparent sedimentation rate is used in the calculation. Here, we propose that based on the principle of 210Pb dating, the upper limit of age suitable for direct 210Pb dating is between 110 and 155 years. The “prolonging” application is acceptable only if the sedimentary environment in the past several hundred years was stable and the sedimentation rate was generally constant, and verification with independent evidence (such as historical records or biomarker methodology) is needed. Furthermore, after analyzing many published and collected data, we found four possible reasons for the “loss of age”. First, the compaction effect of sediment should be corrected in laboratory analysis or else the calculated age will be underestimated. Second, the accuracy and uncertainty of 210Pb activity measurement affect the judgment of the background. To be cautious, researchers are apt to choose a background activity with a younger age. Third, use of a slightly smaller value of supported 210Pb activity in a calculation will lead to considerable underestimation of the time span. Finally, later-stage erosion and migration are common for sedimentation, which lead to loss of sedimentary records and are often reflected as a “loss of age” in cores. We believe that proper use of 210Pb dating data may provide helpful information on our understanding of sediment records and recent environmental changes. [ABSTRACT FROM AUTHOR]

Background: Mesenchymal stem cells (MSCs)-derived extracellular vesicles (EVs) have been reported to exhibit therapeutic effects in various animal models of neurological diseases, such as stroke and hypoxic-ischemic brain injury.Objective: The present study investigated the potential beneficial effect of MSC-derived EVs in an animal model of Alzheimer's disease (AD).Methods: APP/PS1 mice and their non-transgenic littermates (WT) received intracerebroventricle injection of MSC-derived EVs once per two days for two weeks. Then novel object recognition and water maze tasks were carried out to measure the cognitive behaviors. Electrophysiological tests were carried out to measure hippocampal synaptic plasticity. Inducible nitric oxide synthase (iNOS) mRNA and protein levels were measured by qRT-PCR and western blotting in primary cultured neurons treated with amyloid-β peptide (Aβ) or prepared from APP/PS1 mice.Results: Treatment with MSC-derived EVs alleviates exogenous Aβ-induced iNOS mRNA and protein expression. In cultured primary neurons prepared from APP/PS1 pups, iNOS mRNA and protein levels were significantly reduced when treated with MSC-derived EVs. MSC-derived EVs improved cognitive behavior, rescued impairment of CA1 synaptic transmission, and long-term potentiation in APP/PS1 mice.Conclusion: MSC-derived EVs possessed beneficial effects in a mouse model of AD, probably by suppressing Aβ induced iNOS expression. [ABSTRACT FROM AUTHOR]

Resulting from the rising levels of atmospheric carbon, ocean acidification has become a global problem. It has significant impacts on the development, survival, growth and physiology of marine organisms. Therefore, a high-precision sensor is urgently needed to measure the pH of sea-water. Iridium wire with a diameter of 0.25 mm is used as the substrate, and an Ir/Ir(OH) pH electrode is prepared by a one-step electrochemical method in a LiOH solution at the room temperature. A scanning electron microscope (SEM) observation reveals that it is coated with nanoscale particles. In laboratory tests, the electrode exhibits a very promising pH response, with an ideal Nernst slope (56.14-59.52), fast response, good stability and long life-span in tested pH buffer solutions. For a sea trial, four pH electrodes and one Ag/AgCl reference electrode are integrated with a self-made chemical sensor, and a profile detection of nearly 70 m is implemented near Newport Harbor, California on August 3, 2015. The results reflect that the pH value measured by the sensor is very close to the data given by Sea-Bird 911 plus CTD, with a difference value ranging from 0.000 075 to 0.064 719. And the sensor shows a better data matching degree in 0-40 m water depth. In addition, the high precision and accuracy of the sensor make it possible to use in the ocean observation field. [ABSTRACT FROM AUTHOR]