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Ti-6Al-4V titanium alloy weldments were prepared using conventional TIG and fast-frequency double-pulse TIG (FFDP TIG) waveforms. Arc shape, microstructure, and mechanical properties of weldments were investigated. The arc core area of the FFDP TIG shrinks gradually, and the weldment fusion zone (FZ) width and heat-affected zone (HAZ) width are reduced by 18.2% and 31.3%, respectively. The molten pool intensive stirring effect and the heat input reduction by FFDP TIG waveform resulted in the prior β grain size decreased by 55.6% and the refinement of martensite αʹ structures. Microhardness and tensile strength of FFDP TIG weldment were higher than that of conventional TIG; the tensile strength and elongation reached 98.4% and 65.6% of the base metal, respectively. The results show that the FFDP-TIG process improves the Ti-6Al-4V weldment microstructure and mechanical properties and can perform excellently in practical applications. [ABSTRACT FROM AUTHOR]

A better understanding of how the vertical profile of suspended sediment concentration (SSC) is influenced by multiple factors is required to better understand the hydrodynamics and sediment dynamics of estuaries. Based on in situ measurements obtained during a spring-neap cycle in the estuarine turbidity maximum (ETM) of the Changjiang Estuary in January 2015, we investigate the intratidal evolution and controlling mechanisms of SSC profiles. The results show that during the dry season the ETM was characterized by periodic salinity stratification, low SSC, suspended sediments with reduced grain size, and low sediment availability for resuspension. Three types of SSC profiles were identified, i.e., profiles with two-layer, linear and quasi-uniform structures. The shapes of the SSC profiles varied with time and generally deviated from the equilibrium profile due to the highly variable hydrodynamic and sediment conditions. During ebbs of spring and intermediate tides, the SSC profiles generally evolved from a two-layer to a quasi-uniform structure via a linear structure. Analysis shows that the linear and quasi-uniform profiles occurred under the combination of vertically well-mixed salinity, negligible resuspension, low settling velocity associated with very fine grains, and shallow water depth. Such an evolution pattern can be well reproduced using a one-dimensional numerical model, with the diffusion coefficient being parabolically distributed in the water column and the four factors mentioned above. The findings reported here imply a high variability of SSC profiles in estuarine environments. • Three typical types of SSC profiles were observed in the partially and periodically stratified estuary. • SSC profiles often deviated from equilibrium due to highly variable estuarine conditions. • Prerequisites for the formation of linear and quasi-uniform SSC profiles were identified. • Typical evolution patterns of SSC profiles were reproduced using a 1D numerical model. [ABSTRACT FROM AUTHOR]

Purpose: Long non-coding RNAs (lncRNAs) may act as oncogenes in several cancers, including endometrial carcinoma (EC). The purpose of the current study is to investigate the regulatory mechanism of exosomal-lncRNA deleted in lymphocytic leukemia1 (DLEU1) on EC. Methods: The expression levels of lncRNA DLEU1, microRNA-381-3p and E2F Transcription Factor 3 (E2F3) in EC tissues or cells were detected using quantitative reverse transcription–polymerase chain reaction (qRT-PCR). We then analysed the proliferation, migration, and invasion of EC cells by performing the MTT assay, wound healing assay, and transwell invasion assay, respectively. Identification of exosomes was detected using Western blot assay. The uptake of exosomes was detected by a confocal microscope. The effects of exosomes on EC cells were investigated by construction of cell co-culture system. The interactions among DLEU1, miR-381-3p and E2F3 were confirmed using the dual-luciferase reporter (DLR) assay. Results: LncRNA DLEU1 expression was highly up-regulated in EC tissues and cells. Knockdown of DLEU1 inhibited the proliferation, migration, and invasion of EC cells. Exosomes could be uptaken by the ambient EC cells. MiR-381-3p was a target of DLEU1 and was negatively modulated by DLEU1. Overexpression of miR-381-3p suppressed the proliferation, migration, and invasion of EC cells. Additionally, E2F3 was the target gene of miR-381-3p and was negatively modulated by miR-381-3p. Upregulation of miR-381-3p and down-regulation of E2F3 reversed the promoting effect of exosomal DLEU1 on EC cells. Conclusion: Exosomal DLEU1 accelerates the development of EC by regulating the miR-381-3p/E2F3 axis, thus DLEU1 may act as a possible therapeutic target for treating EC. [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]

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 quantitative analysis of sediment sources in a sink is an important scientific topic and challenge in provenance research. The characteristics of heavy minerals, combined with the geochemical constituents of detrital grains, provide a reliable provenance-tracing approach. We developed a mineral identification method to analyze the multiple grain-size fraction of sediments, from which the elemental geochemistry of hornblende was used to compare the characteristics of sediments from the Huaihe River and Huanghe (Yellow) River in eastern China. Elements that were statistically identified as being able to discriminate sediment provenance were employed to perform a quantitative analysis of the sources of sediments of the abandoned Huanghe River. Results reveal that the Huaihe River is characterized by a high amphibole content of >60% and that the Huanghe and abandoned Huanghe rivers have greater abundances of limonite and carbonate minerals compared with those of the Huaihe River. The contents of trace elements and rare earth elements in hornblende show that the sediments of the abandoned Huanghe River are similar to those of the Huanghe River but different from those of the Huaihe River. Furthermore, chemical mass balance was used to calculate the relative contributions of different provenances of sediment from the abandoned Huanghe River, and nine trace elements of hornblende were identified as discriminators of provenance. Approximately 2% of the hornblende in the abandoned Huanghe River is derived from the Huaihe River and 98% from the Huanghe River. Considering the proportion of hornblende in the total sediment, it is inferred that the contribution of Huaihe River sediment to the abandoned Huanghe River is approximately 0.5%. This study shows that mineral analysis using multiple grain-size fractions (within the wide range of 1Φ to 6Φ) with assessment in elemental geochemistry of hornblende can characterize the provenance of fluvial material in coastal zones. [ABSTRACT FROM AUTHOR]

Abstract: To study the fluvial interaction between Changjiang River and Poyang Lake, we analyze the observed changes of riverine flux of the mid-upstream of Changjiang River catchment, the five river systems of Poyang Lake and Poyang Lake basin. Inter-annual and seasonal variations of the water discharge and sediment exchange processes between Changjiang River and Poyang Lake are systematically explored to determine the influence of climate change as well as human impact (especially the Three Gorges Dam (TGD)). Results indicate that climate variation for the Changjiang catchment and Poyang Lake watershed is the main factor determining the changes of water exchanges between Changjiang River and Poyang Lake. However, human activities (including the emplacement of the TGD) accelerated this rate of change. Relative to previous years (1956–1989), the water discharge outflow from Poyang Lake during the dry season towards the Changjiang catchment increased by 8.98km3 y−1 during 2003–2010. Evidently, the water discharge flowing into Poyang Lake during late April–late May decreased. As a consequence, water storage of Poyang Lake significantly reduced during late April–late May, resulting in frequent spring droughts after 2003. The freshwater flux of Changjiang River towards Poyang Lake is less during the flood season as well, significantly lowering the magnitude and frequency of the backflow of the Changjiang River during 2003–2010. Human activities, especially the emplacement and operation of the TGD and sand mining at Poyang Lake impose a major impact on the variation of sediment exchange between Changjiang main river and Poyang Lake. On average, sediments from Changjiang River deposited in Poyang Lake before 2000. After 2000, Changjiang River no longer supplied sediment to Poyang Lake. As a consequence, the sediment load of Changjiang River entering the sea increasingly exists of sediments from Lake Poyang during 2003–2010. As a result, Poyang Lake converted from a depositional to an erosional system, with a gross sediment loss of 120.19Mty−1 during 2001–2010, including sand mining. [Copyright &y& Elsevier]

In order to investigate obscuration in high-luminosity type 2 active galactic nuclei (AGNs), we analyzed Chandra and XMM-Newton archival observations for 71 type 2 quasars detected at 0.05 < z < 0.73, which were selected based on their [O III] λ5007 emission lines. For 54 objects with good spectral fits, the observed hard X-ray luminosity ranges from 2 × 1041 to 5.3 × 1044 erg s–1, with a median of 1.1 × 1043 erg s–1. We find that the means of the column density and photon index of our sample are log NH = 22.9 cm–2 and Γ = 1.87, respectively. From simulations using a more physically realistic model, we find that the absorbing column density estimates based on simple power-law models significantly underestimate the actual absorption in approximately half of the sources. Eleven sources show a prominent Fe Kα emission line (EW>100 eV in the rest frame) and we detect this line in the other sources through a joint fit (spectral stacking). The correlation between the Fe Kα and [O III] fluxes and the inverse correlation of the equivalent width of the Fe Kα line with the ratio of hard X-ray and [O III] fluxes is consistent with previous results for lower luminosity Seyfert 2 galaxies. We conclude that obscuration is the cause of the weak hard X-ray emission rather than intrinsically low X-ray luminosities. We find that about half of the population of optically selected type 2 quasars are likely to be Compton thick. We also find no evidence that the amount of X-ray obscuration depends on the AGN luminosity (over a range of more than three orders of magnitude in luminosity). [ABSTRACT FROM AUTHOR]

In many estuaries, current velocity, suspended sediment concentration (SSC), and water depth have notable flood-ebb asymmetries in magnitude or duration. Such asymmetries can make marked impact on estuarine sediment transport and require in-depth analysis of the underlying mechanism. Based on field measurement over a neap-spring cycle in the Changjiang Estuary in January 2015, net suspended sediment transport modulated by multiple asymmetries were analyzed. The results showed that there were notable flood-ebb asymmetries in the current velocity, current duration, SSC, and water depth. The former two were ebb-dominated, while the latter two were flood-dominated. The net suspended sediment transport was landward and exhibited remarkable tidal fluctuation in magnitude. Ebb-dominated velocity and duration asymmetries favored seaward transport, but flood-dominated SSC and water depth asymmetries promoted landward transport. The relative contribution of these asymmetries to the net sediment transport was different and closely related to their asymmetry intensities. The magnitude of net sediment transport was highly modulated by the combined effects of these asymmetries. Further analyses revealed that the ebb-dominated asymmetries in velocity and duration were controlled by river flow, tidal wave deformation, and compensation flow of Stokes drift. The flood-dominated water depth asymmetry was related to the progressive tidal wave. The flood-dominated SSC asymmetry was mainly attributed to the lower SSCs in early ebbs, notable sediment supply limitation in late ebbs, wind wave height asymmetry, and gravitational circulation. Additionally, it is worth noting that the progressive tidal wave can yield strong current asymmetry, notable water depth asymmetry, and obvious wind wave height asymmetry during strong wind periods. • Multiple important flood-ebb asymmetries coexist in a tidal cycle in natural estuaries. • Net sediment transports are highly modulated by the combination of multiple asymmetries. • Flood- and ebb-dominated asymmetries play opposite roles in net sediment transport. • Compensation flow of Stokes drift has important influence on current asymmetry. • Variation in sediment availability for resuspension can yield notable SSC asymmetry. [ABSTRACT FROM AUTHOR]

The optical reference cavity in an ultrastable laser is sensitive to vibrations; the microvibrations in a space platform affect the accuracy and stability of such lasers. In this study, an active vibration isolation controller is proposed to reduce the effect of vibrations on variations in the cavity length and improve the frequency stability of ultrastable lasers. Based on the decentralized control strategy, we designed a state-differential feedback controller with a linear quadratic regulator (LQR) and added a disturbance observer (DOB) to estimate the source noise. Experiments were conducted using an active vibration isolation system; the results verified the feasibility and performance of the designed controller. The accelerations along the axis (Z-, X-, Y-) directions were suppressed in the low-frequency band within 200 Hz, and the root-cumulative power spectral densities (PSDs) declined to 1.17 × 10−5, 7.16 × 10−6, and 8.76 × 10−6 g. This comprehensive vibration met the requirements of an ultrastable laser. [ABSTRACT FROM AUTHOR]

Two field campaigns in Dafeng and Jianggang were organized to compare spatial variations of hydrodynamic characteristics and sediment transport patterns on intertidal flats of different types with distinct human interferences along middle Jiangsu coast, China. The major contributors to the different patterns of sediment dynamics between the two tidal flats were offshore tidal current field and human interference. Offshore tidal force provide the basic setup of tidal current patterns on tidal flats, which is then modified by local morphology. Seawalls parallel to coast reduce tidal flat width, forcing tidal energy to dissipate within a shorter distance and thus influencing tidal flat morphology. Seawalls vertical to coast and major tidal current significantly reduce tidal current speed, which favors sediment deposition on tidal flats. Two seawalls built on both sides of the observational tidal flat profile caused much reduced current speed at Dafeng tidal flat, comparing to the offshore station. Being exposed to offshore radial tidal currents, hydrodynamics at Jianggang was much stronger than that at Dafeng. Residual currents at both areas showed net landward transport at the lower flat and net seaward transport at the upper flat, in favor to sediment accumulation at the middle flat. Sediment flux over tidal cycles showed net landward sediment transport at Dafeng, and net seaward transport at Jianggang, consistent with the convex-up accretion-dominated profile observed at Dafenge, and concave-up erosion-dominated profile observed at Jianggang. The instantaneons sediment flux changed significantly due to variations in velocity and sediment concentrations, but these terms counteracted with each other within tidal cycles, leading to the dominant role of Eulerian flux in determining net sediment flux over tidal cycles. [ABSTRACT FROM AUTHOR]

Abstract: The sources and burial patterns of organic matter in Shamei Lagoon, Hainan, China, were investigated by analyzing the collected sediment cores, in terms of the variations in total organic carbon (TOC), total nitrogen (TN), stable carbon isotopic composition (δ13C and δ15N), and the ratio of total organic carbon to total nitrogen (TOC/TN). On such a basis, the environmental evolution and primary productivity changes of the lagoon were revealed, and the impacts of both natural environmental changes and human activities were identified. Downcore variation patterns of the parameters representing sources and burial flux of organic matter were predominantly related to natural evolution of the lagoon from 1800 to 1950 and they were increasingly affected by human activities afterwards. In the period 1800–1900, the water exchange capacity of the lagoon declined substantially, but it was still suitable for the growth of marine phytoplankton, as is indicated by relatively high proportion and burial flux of organic matter originated from marine sources. During 1900–1950, the lagoon was transformed into a freshwater environment. After 1950, due to strong influence by human activities, the local freshwater phytoplankton became the major source of buried organic matter; at the same time, marine lost its niche and its burial flux was much lower than that of its freshwater counterpart. The large increment of buried freshwater organic matter also indirectly reflects the eutrophication trend since 1950. [Copyright &y& Elsevier]

Abstract: Objective: The purpose of this study was to investigate changes of the antigen-presenting function of tumor infiltrating dendritic cells (TIDCs) in human endometrioid adenocarcinoma. Study design: The TIDCs from 45 cases of endometrioid adenocarcinoma were compared with 20 cases of normal human endometrial tissue, using transmission electron microscopic examination, and the expression of CD80, CD86, and CD40 was analyzed by flow cytometry. Results: In comparison with the control group, the ultrastructure of TIDCs in human endometrioid adenocarcinoma showed the following differences: numerous TIDCs were small in volume and round in shape but some were oval and multi-angular. The cytoplasmic processes were obviously decreased in number and stubbed. Round primary lysosomes with high electron-dense granules, and secondary lysosomes with high or low electron-dense granules were seen frequently in the cytoplasm. TIDCs contained much rough endoplasmic reticulum (RER). Vacuoles with flocculent electron-dense granules were rare. High electron-dense contents in the granules were near one side and the other side was bright. The nucleus became markedly small in volume, nephroid or hoofed in shape. The nucleus had little euchromatin and lots of heterochromatin under the nuclear membrane. The levels of expression of CD80, CD86 and CD40 on TIDCs were low or even nonexistent. The expression levels of CD80, CD86 and CD40 on DCs in human normal endometrium were significantly higher than those on TIDCs in endometrioid adenocarcinoma. Conclusion: It is suggested that morphological differences and low expression of co-stimulatory molecules on TIDCs in endometrioid adenocarcinoma reflected the functional changes of the TIDCs in uptake, processing and presenting antigen, which may lead to the occurrence of tumor immune escape. [Copyright &y& Elsevier]

Abstract: With Rytov approximation and Kolmogorov spectrum model of index-of-refraction fluctuation, we study the effects of turbulence aberration on the orbital angular momentum of single photons in atmospheric communication channel. A theoretical model of measurement probabilities of orbital angular momentum states for single photons propagation under the Zernike tilt corrected slant path turbulent atmosphere channel is established. Our research shows that tilt-corrected residual aberration not only damage the initial OAM, but also induce new OAM. With the increasing of D/ρ 0, the number of the initial OAM photons will go down while the effective number of new OAM ascends. Meanwhile, the receiving probability of initial OAM photons declines, as the turbulence shifts from weak to strong. For Zernike tilt-corrected residual aberration, the receiving probability of initial OAM photons declines as the diameter of detector increases. The effect of Zernike tilt-corrected residual aberration on OAM of the photons is more larger than the effect of Zernike tilt turbulent aberration. [Copyright &y& Elsevier]

The stability of nitric acid oxidized carbon nanotubes (CNTs) and the precipitation of oxidized CNTs in water by salts were investigated. Stability investigation shows that during an aging time of 30 days, oxidized CNTs dispersion shows characteristic UV–vis absorbance peak of individual CNTs at 252nm and CNTs concentration in the dispersion after 30d aging is 85% of the initial concentration. The precipitation value of salts were measured and the precipitation value follows the order of NaCl>KCl>1/2(MgCl2)>1/2(CaCl2)>1/3(FeCl3)>1/3(AlCl3). The nature of anions investigated has little effect on precipitation values of salts. [Copyright &y& Elsevier]

A MIDAS-400 customized data acquisition system has been used for the high-resolution sediment dynamic measurements over the Dafeng intertidal flats of northern Jiangsu during 6 tidal cycles from July 3 to July 10, 2003. The bed shear stress and bedload transport rates, in response to wave-current interactions, are calculated, which indicate that wind waves enhance the bottom shear stress and bedload transport rates. At the station for measurements, bedload transport was directed to seaward, with a sediment discharge of 30-150 kg·m-1 per tidal cycle. The surficial sediment samples were collected from a grid with 10 m spatial intervals over a rectangle 2 × 104 m² experimental area, near the MIDAS-400 during the spring tide of July 4, 2003, and the neap tide of July 9, 2003. In addition, leveling survey was undertaken to obtain the detailed topography of the sampling area. Grain-size trend analysis of the sediment samples shows that the bedload transport patterns are complex, mainly controlled by the hydrodynamics and local geomorphology (e.g. tidal creeks) over the intertidal flats. Furthermore, the grain-size trends pattern during the neap tide rather than during the spring tide is consistent with the calculated bedload transport, and the grain-size trend vectors for the spring tide are larger than those for [ABSTRACT FROM AUTHOR]

To detect low-frequency gravitational waves, it is necessary to eliminate the interference of geo-noise and build a laser interference gravitational-wave detection device in space. Space gravitational-wave detection missions, namely Taiji, LISA, and Tianqin, have been planning to achieve picometer sensitivity on an interferometer arm of several million kilometers to meet the gravitational-wave detection requirements. Because of the orbit evolution and the time delay in interferometer arms, the direction of the transmitted laser beam changes; consequently, a remote telescope cannot receive the laser beam to complete the inter-satellite laser interference. In this study, a two-dimensional point-ahead angle mechanism (2DPAAM) is designed and demonstrated to solve the aforementioned problem. Based on the design concept of aligning the rotation center with the mirror surface center, the 2DPAAM employs a four-link flexible-hinge structure, length expanding and contracting piezoelectric stack actuators, and closed-loop control of capacitive sensors to realize two-dimensional picometer-stable, high-precision rotation. A static model is established to analyze the rotational characteristics, and finite element analysis is performed to study the mechanical properties and to verify the rotational characteristics. The yaw and pitch stiffness errors are ∼0.93% and 5.9%, respectively, when the theoretical results are compared with the simulation results. A series of experiments are conducted on the developed 2DPAAM, and the results show that the rotary ranges of yaw and pitch motions attain ±270 and ±268 µrad, respectively. The rotational accuracies of both yaw and pitch motions attain ∼0.35 µrad, and the optical path difference is less than 10 pm / Hz when the frequency is between 1 mHz and 1 Hz, by analogy. [ABSTRACT FROM AUTHOR]

Continental shelf islands are contributors of terrestrial sediment supply to shelf regions, and the sediment flux from these islands shall be quantified. We calculated the sediment flux of continental shelf islands in the southeastern China using two empirical equations under two preconditions. The first, the sediment load/yield of the islands has the same pattern as the adjacent small, mountainous rivers along the coastline; and the second, each of the islands was treated as a single catchment. The results show that the sediment supply from these islands reached an order of magnitude of 1 Mt/a, which is comparable to the supply from the local smaller rivers. A sensitivity analysis indicates that this value represents the lower limit of estimate; if the accurate amount of sub-catchments of any island is considered, then this value will be enhanced slightly. This study demonstrates that the sediment supply from continental shelf islands to oceans is an important factor affecting the regional sedimentation and, therefore, should be paid with attention. [ABSTRACT FROM AUTHOR]

Background: Gut microbiota could affect the onset and development of vascular cognitive impairment (VCI) through modulating metabolic and immune pathways. However, the vascular mechanisms involved remain unclear. Objective: To investigate the gut microbiota associated with VCI and examine the mediating effects of regional cerebral blood flow (CBF) to explore potential therapeutic targets for VCI. Methods: This prospective study enrolled patients with VCI (n = 16) and healthy controls (n = 18) from the Chinese Imaging, Biomarkers, and Lifestyle study between January 1 and June 30, 2022. The gut microbiota composition and diversity were determined by 16 S ribosomal RNA gene sequencing. The association between gut microbiota and Montreal Cognitive Assessment (MoCA) scores was determined using Spearman's correlation analysis. Regional CBF was calculated using pseudo-continuous arterial spin labeling. The mediating effects of regional CBF on the relationship between specific gut microbiota and cognition in VCI were investigated using mediation analysis. Results: Compared to healthy controls, patients with VCI had significantly greater abundance of Bifidobacterium, Veillonella, R uminococcus gnavus , Fusobacterium, and Erysipelatoclostridium and smaller abundance of Collinsella. The abundance of Ruminococcus gnavus was negatively associated with MoCA scores in patients with VCI, with the CBF in the left hypothalamus, right hypothalamus, and left amygdala accounting for 63.96%, 48.22%, and 36.51%, respectively, of this association after adjusting for confounders. Conclusions: Ruminococcus gnavus is associated with cognition in VCI, which is strongly mediated by CBF in the bilateral hypothalamus and left amygdala. These findings highlight the potential regulatory roles of nutrition and metabolism-related areas of the brain in VCI. [ABSTRACT FROM AUTHOR]

Future GRACE-like geodesy missions could benefit from adopting accelerometer technology akin to that of the LISA Pathfinder, which employed laser interferometric readout at the sub-picometer level in addition to the conventional capacitive sensing, which is at best at the level of 100 pm. Improving accelerometer performance holds great potential to enhance the scientific output of forthcoming missions, carrying invaluable implications for research in climate, water resource management, and disaster risk reduction. To reach sub-picometer displacement sensing precision in the millihertz range, laser interferometers rely on suppression of laser-frequency noise by several orders of magnitude. Many optical frequency stabilization methods are available with varying levels of complexity, size, and performance. In this paper, we describe the performance of a Mach–Zehnder interferometer based on a compact monolithic optic. The setup consists of a commercial fiber injector, a custom-designed pentaprism used to split and recombine the laser beam, and two photoreceivers placed at the complementary output ports of the interferometer. The structural stability of the prism is transferred to the laser frequency via amplification, integration, and feedback of the balanced-detection signal, achieving a fractional frequency instability better than 6 parts in 10 13 , corresponding to an interferometer pathlength stability better than 1 pm / Hz . The prism was designed to host a second interferometer to interrogate the position of a test mass. This optical scheme has been dubbed "single-element dual-interferometer" or SEDI. [ABSTRACT FROM AUTHOR]

A new off-axis optical design alternative to that of the GRACE Follow-on mission for future NGGM missions is considered. In place of the triple-mirror assembly of the GRACE Follow-on mission, a laser retro-reflector is instead generated by means of lens systems. The receiving (RX) beam and transmitting (TX) beam are enforced to be anti-parallel by a control loop with differential wavefront sensing (DWS) signals as readout, and a fast-steering mirror is employed to actuate the pointing of the local beam. The tilt-to-length (TTL) coupling noise of the new off-axis optical bench layout is carefully studied in the present work. Local TTL originated from piston noise as well as assembly and alignment errors of optical components are studied. Effort is also made to have an in depth understanding of global TTL due to relative attitude jitter between spacecraft. The margin of TTL noise in the position noise budget for laser ranging is examined. With an open loop control of the offset between the reference point of the optical bench and the centre of mass of a satellite, the TTL noise of the new off-axis optical bench design may be suppressed efficiently. [ABSTRACT FROM AUTHOR]

This paper evaluates the potential application of Raman baselines in characterizing organic deposition. Taking the layered sediments (Stromatolite) formed by the growth of early life on the Earth as the research object, Raman spectroscopy is an essential means to detect deep-space extraterrestrial life. Fluorescence is the main factor that interferes with Raman spectroscopy detection, which will cause the enhancement of the Raman baseline and annihilate Raman information. The paper aims to evaluate fluorescence contained in the Raman baseline and characterize organic sedimentary structure using the Raman baseline. This study achieves spectral image fusion combined with mapping technology to obtain high spatial and spectral resolution fusion images. To clarify that the fluorescence of organic matter deposition is the main factor causing Raman baseline enhancement, 5041 Raman spectra were obtained in the scanning area of 710 μm × 710 μm, and the correlation mechanism between the gray level of the light-dark layer of the detection point and the Raman baseline was compared. The spatial distribution of carbonate minerals and organic precipitations was detected by combining mapping technology. In addition, based on the BI-IHS algorithm, the spectral image fusion of Raman fluorescence mapping and reflection micrograph, polarization micrograph, and orthogonal polarization micrograph are realized, respectively. A fusion image with high spectral resolution and high spatial resolution is obtained. The results show that the Raman baseline can be used as helpful information to characterize stromatolite organic sedimentary structure. [ABSTRACT FROM AUTHOR]

We present a Chandra observation of IRAS 19254–7245, a nearby ultraluminous infrared galaxy also known as the Superantennae. The high spatial resolution of Chandra allows us to disentangle for the first time the diffuse starburst (SB) emission from the embedded Compton-thick active galactic nucleus (AGN) in the southern nucleus. No AGN activity is detected in the northern nucleus. The 2-10 keV spectrum of the AGN emission is fitted by a flat power law (Γ = 1.3) and an He-like Fe Kα line with equivalent width ∼1.5 keV, consistent with previous observations. The Fe Kα line profile could be resolved as a blend of a neutral 6.4 keV line and an ionized 6.7 keV (He-like) or 6.9 keV (H-like) line. Variability of the neutral line is detected compared with the previous XMM-Newton and Suzaku observations, demonstrating the compact size of the iron line emission. The spectrum of the galaxy-scale extended emission excluding the AGN and other bright point sources is fitted with a thermal component with a best-fit kT of ∼0.8 keV. The 2-10 keV luminosity of the extended emission is about one order of magnitude lower than that of the AGN. The basic physical and structural properties of the extended emission are fully consistent with a galactic wind being driven by the SB. A candidate ultraluminous X-ray source is detected 8″ south of the southern nucleus. The 0.3-10 keV luminosity of this off-nuclear point source is ∼6 × 1040 erg s–1 if the emission is isotropic and the source is associated with the Superantennae. [ABSTRACT FROM AUTHOR]

This study analyzed the characteristics and the bearing capacity of water surge disasters in Boao Bay, a typical estuarine lagoon. The Danish Hydraulic Institute's (DHI's) MIKE 21 modeling suite was used to numerically simulate the water surges from flood, storm, and combined flood and storm processes. The results show that, in Boao Bay, the peak water surge level caused by the combination of flooding and storm surges is very similar to the level caused by flooding or storm surges alone. Additionally, the storm surge bearing capacity is much greater than the flood bearing capacity. When there is only one entrance, the bay's flood bearing capacity increases with the entrance width, but when the entrance width exceeds 550 m, the flood bearing capacity stabilizes rapidly. However, opening an additional entrance to the south can further increase the flood bearing capacity. Based on hydrometeorological forecasts, this study suggests that the risk of water surge disasters can be reduced by proactively modifying the shape of the entrance. [ABSTRACT FROM AUTHOR]

Large polyethylene glycol (PEG) is a standard regimen for bowel preparation. However, elderly patients suffered from adverse events. This study was to compare the efficacy and safety of oral magnesium sulfate solution (MSS) vs standard PEG in elderly patients undergoing colonoscopy. Elderly patients aged 60–90 years, from two endoscopic centers, were enrolled in China. Patients were randomized to take a low dose of MSS or a standard PEG regime in a split-dose regime. The primary endpoint was the proportion of patients with adequate bowel preparation, which was defined as the total Boston Bowel Preparation Scale (BBPS) ≥6 and each segmental BBPS was ≥2. Secondary outcomes included adenoma detection rate (ADR), safety, adverse events, cecal intubation rate, willingness to repeat BP, and so on. 1174 elderly patients were randomly allocated to the MSS group (n = 588) or the standard group (n = 586). Adequate BP was achieved in 94.0% of patients in the MSS group and 92.5% in the control (p =.287). ADR was also comparable between the two groups (43.0% and 39.9%, p =.282). Compared with the standard group, MSS group reported less abdominal discomfort (1.7% vs 6.0%), less nausea (13.6% vs 21.0%) and vomiting (1.2% vs 4.2%). The change in serum potassium levels after preparation in the standard group was significantly lower than that in the MSS group (−0.19 ± 0.08 vs −0.41 ± 0.11, p =.037). Low dose of MSS was not inferior to the standard PEG regime in terms of bowel preparation quality for elderly patients. Low-dose MSS offered fewer adverse events and better tolerability. It is a preferable choice for the elderly to undergo bowel preparation for colonoscopy. NCT 04948567 [ABSTRACT FROM AUTHOR]

Delta evolution in the context of no sediment discharge has become a global concern, and an accretion-to-erosion conversion is occurring in the Yangtze estuary. This conversion could threaten Changjiang subaqueous delta development. Sediment erodibility is an important indicator of subaqueous delta vulnerability. However, the present and future erodibility of the Changjiang subaqueous delta remains unclear. In this study, 37 short cores were collected from the Changjiang subaqueous delta, and the critical shear stress of the sediment was measured using a cohesive strength meter (CSM) and compared with estimates based on an empirical Shields diagram. The sediment erodibility was analyzed by comparing the sediment critical shear stress with the bed shear stress simulated using a numerical model (i.e., FVCOM), and sediment activity was introduced to discuss the geomorphological change in the subaqueous delta. The CSM-derived critical shear stress is significantly higher than that derived from the empirical Shields formula, but it better shows the erodibility of the sediment. The annual surface sediment activity ranges from 5% to 30% based on the CSM, indicating low surface erodibility. Moreover, the critical shear stress in this region increases as water depth increases, but the bed shear stress shows the opposite trend. Therefore, the erodibility of the Changjiang subaqueous delta is lower than that of the shallow area, indicating no accretion-erosion conversion or continued vertical erosion under sediment starvation in the coming decades. These findings can provide suggestions for erosion assessment and management in large river deltas under decreasing sediment discharge. [ABSTRACT FROM AUTHOR]

The Poyang Lake catchment, an important sub-catchment of Changjiang, experienced ‘Little Ice Age’ (LIA) and accelerating intensity of human activities during the last 1000 years. As such, the area and time period serve as a perfect case to study the variations in water and sediment discharge under combined natural and anthropogenic impact. Simulation results of the model HydroTrend indicate that the annual average cumulative water discharge of the five rivers entering Poyang Lake over the last 1000 years is 103.65 ± 1.80 km3, and climate change is the dominating factor determining water discharge variations over time. Influenced by the LIA (AD 1451–1850), the total water discharge of the five rivers was reduced by 10%. Sediment load discharging into Poyang Lake by the five rivers was only 9.21 ± 0.43 Mt yr−1 between AD 1000 and 1700, when the anthropogenic impact on the landscape was still low. However, with the human activities accelerating during the past 300 years, the sediment load entering Poyang Lake underwent a drastic change. Because of intensified soil loss, the total sediment load entering Poyang Lake during AD 1800–1950 increased by 58.7%, compared with AD 1000–1700. After AD 1950, the sediment load variation is mainly reflected by the combined impact of dam emplacement and soil erosion. As sediment interception by dams continuously increased over time, the total sediment load entering Poyang Lake during AD 1990–2000 is only 60.9% of that of the highest riverine sediment flux during AD 1951–1980, which is almost equal to that of the lowest level during AD 1000–1700. The sediment load of many rivers in the world exhibited similar variation trends as that of Poyang Lake under combined impact of climate change and human activities. Better understanding the mechanisms of these variation trends is helpful to analyzing the formation and evolution of an estuary-shelf sedimentary system over the Holocene. [ABSTRACT FROM AUTHOR]

Coastal zones, including a large number of sea islands, have experienced profound and often lasting landscape changes over the past half century. Understanding the drivers and ecological effects of these changes is a prerequisite for large-scale integrated coastal zone management (ICZM). In this study, landscape patterns of Tantoushan Island, China, for 1966, 2004, and 2012 were produced through landscape identification and classification of multi-resource remote sensing KH-7 homochromatic, QuickBird multispectral, and WorldView-2 multispectral imageries, and contemporaneous historical data. Analysis of landscape changes and drivers has shown drastic changes from 1966 to 2012, caused by afforestation, changes in exploitation methods, human-induced fire and diseases, as well as natural succession. Here, a simple weighted sum of CN values representing the runoff potential of specific landscape types from the TR-55 runoff prediction model was calculated to reflect the runoff potentials of the three different periods. The results suggest a marked fluctuation in runoff potential of Tantoushan Island from 1966 to 2012, despite an afforestation program since 1949 to optimize the vegetation structure of the island. Measures such as ecological restoration of bare land and improvement of afforestation tree species should be adopted to improve the management of Tantoushan Island. [ABSTRACT FROM AUTHOR]

There are concerns that intense tropical cyclones (TCs) are expected to become more frequent and powerful in warming climates. However, the long-term trend of TC activities, the spatiotemporal variability of such trends across different latitudes of the Western North Pacific (WNP), and the drives of the variability remain unclear. Here, we present a reconstruction of a 1600-year paleo-TCs activity using a sediment core taken in Li'an Lagoon located in southeastern Hainan Island, South China Sea. We used muti-dating methods (210Pb and AMS 14C dating) for age control and muti-proxy analysis (XRF geochemical element scanning and grain size analysis) for identifying periods of frequent intense TC activities. Based on an updated compilation of basin-wide paleo-TC records, we confirm that there exists a seesaw pattern of intense TC frequency between low and middle latitude in the WNP. Comparing with global and regional paleoclimate proxies, we propose that the basin-wide latitudinal TC activity variation in the WNP can be linked to the migration of Western Pacific Subtropical High (WPSH) and its associated high-latitude forcings (e.g., NAO) and low-latitude internal variability forcings (i.e., El Niño Southern Oscillation, sea surface temperature (SST)). More intense TC will occur at low latitudes in the future, though with less frequency. • A 1600 years high-resolution paleo-TCs records are reconstructed. • A clearly seesaw pattern were identified between TC activity at low and middle latitude over the WNP were found. • WPSH play an intermediate regulation role in controlling the TC latitudinal shift. [ABSTRACT FROM AUTHOR]

Background: Synaptic abnormalities in synaptic proteins are the initial hallmarks of Alzheimer's disease (AD). The higher level of palmitoylation of synaptic proteins was closely associated with amyloid-β (Aβ) in AD. Cattle encephalon glycoside and ignotin (CEGI) have been shown to act as multitarget neurotrophic agents in APPswe/PS1dE9 (APP/PS1) transgenic AD mice. However, it is not clear whether CEGI can influence Aβ deposition or whether it does so by the regulation of protein palmitoylation and expression of synaptic proteins in transgenic AD mice.Objective: In this study, we investigated the roles of CEGI in modulating postsynaptic density protein 95 (PSD-95) palmitoylation, Aβ pathologies, and expression of synaptic-associated proteins in APP/PS1 mice.Methods: Five-month-old APP/PS1 mice were treated intraperitoneally with 6.6 mL/kg of CEGI for 6 weeks. At the end of the treatment period, APP/PS1 mice were subjected to Morris water maze to test their cognitive functions. Acyl-biotinyl exchange (ABE) for PSD-95 palmitoylation, immunofluorescent staining for expression of PSD-95, N-methyl-D-aspartic acid receptor subunit 2B (NR2B), and synaptotagmin 1 (SYT1) were assessed in mouse brain sections.Results: CEGI treatment in APP/PS1 mice significantly reduced Aβ deposition, relieved memory deficits, and decreased PSD-95 palmitoylation while markedly increasing the expression of PSD-95, NR2B, and SYT1 in the frontal cortex. There was a significant correlation between Aβ expression and PSD-95 palmitoylation in APP/PS1 mice.Conclusion: Our findings demonstrate that CEGI improved AD-like neuropathology, possibly by inhibiting PSD-95 palmitoylation, improving learning memory, and enhancing expression of synaptic-associated proteins, representing a potential therapy for AD treatment. [ABSTRACT FROM AUTHOR]

Sediment transport within small tidal inlets is sensitive to natural processes, whilst large tidal inlets are relatively robust systems because of their large tidal prism. However, remarked morphological changes may be initiated even under the condition of low sediment supply, as illustrated by Jiaozhou Bay, a large coastal embayment on the Shandong Peninsula, eastern China. Jiaozhou Bay is characterized by its relatively slow rate of natural change, and while the embayment has a flood-dominated entrance channel and muddy seabed, the suspended sediment concentration is generally low due to the lack of abundant source material. Observations of sediment dynamics show that net suspended sediment transport is directed towards outside of the bay, with an order of magnitude of 10 3 t during a tidal cycle. The export of sediment associated with this flood-dominated environment implies that the net transport pattern is controlled by tidal exchange processes rather than the strength of the seabed shear stress. Sediment budget calculations show that supply of artificial sediment into the bay can account for up to 72% of the total input, which is in agreement with the 210 Pb and 137 Cs radioisotope geochronologies, and this leads to accumulation rates of 10 0 –10 1 mm yr −1 ; without this, the deposition rate would be low under natural conditions. The flood tidal delta area is also influenced by the input of anthropogenic material, and acts as a depocenter with relatively high accumulation rates. Furthermore, although the inlet system has not yet reached its equilibrium state (i.e., the entrance cross-sectional area is still larger than the equilibrium cross-sectional area), land reclamation activities have resulted in a rapid reduction of the embayment area (by 37%) over the last 80 years. Our findings indicate that the rapid changes observed in the tidal basin area and seabed morphology are mainly the result of human activity rather than natural processes. [ABSTRACT FROM AUTHOR]

Frequency changes in intense typhoons are of great concern to modern society. However, current understanding of the influence of climate on typhoon activity on the millennial scale is restricted by the sparseness of pre‐observational reconstructions in the north‐western Pacific. This study presents a 5500 year long typhoon record from the Jiangsu coast that provides the first >2 ka record in eastern China. Variations in the D90 grain size are the best predictor of recent typhoons in a second short high‐resolution core. Comparison with other typhoon records from south‐eastern China establishes a China millennial typhoon variability index during the middle to late Holocene, with maxima at ca 4750 ± 170, 3500 ± 220, 1500 ± 480 and 250 ± 170 yr bp and minima at ca 5200 ± 300, 4150 ± 430, 2600 ± 650 and 750 ± 270 yr bp. Peaks in typhoon activity in south‐eastern China (compared with Japan) correlate with damped (enhanced) El Niño–Southern Oscillation and weak (strong) East Asian Summer Monsoon, indicating a seesaw pattern in typhoon activity between the two regions. A shift in typhoon frequency pattern was also identified around 2000 yr bp in south‐eastern China, with subsequent more frequent typhoon activity. At that time there was sustained Atlantic Meridional Overturning Circulation reduction and its associated El Niño–Southern Oscillation enhancement, so Atlantic Meridional Overturning Circulation‐driven El Niño–Southern Oscillation changes are likely to be the major cause of the significant increase in typhoon activity since 2000 yr bp, resulting in the 1500 ± 480 and 250 ± 170 yr bp China millennial typhoon variability peaks. To accurately predict changes in intense typhoon activity, it is therefore important to understand how the Atlantic Meridional Overturning Circulation and El Niño–Southern Oscillation will respond to future climate change. [ABSTRACT FROM AUTHOR]

Growing evidence has suggested that human activities could cause significant changes in marine sedimentation processes. The spatio-temporal response of sedimentary environment to human activities, however, remains unclear. Here, we present new evidence of sedimentary changes in the East China Sea over the past three decades (i.e., 1984–2016 CE) by using the mean grain size of sensitive components and geochemical parameters (i.e., Si/Ti and Fe/Al) from two sedimentary records from the Zhejiang-Fujian mud belt (ZFMB). Comparison with a compilation of published data shows that natural climate oscillations were the dominant factors that controlled the sedimentation processes before 2005 CE. Variations in the mean grain size of sensitive components over the ZFMB were mainly controlled by the East Asian Winter Monsoon before 2005 CE. The Si/Ti and Fe/Al ratios in the northern and southern of the ZFMB before 2005 CE were controlled by the Pacific Decadal Oscillation/Kuroshio Current and the East Asian Summer Monsoon, respectively. However, our synthesis shows a significant shift in the sedimentation processes between the north and south of the ZFMB since 2005 CE, i.e., after acceleration of the human imprint on sedimentation (e.g., dam construction). The mean grain size of sensitive components and the Si/Ti and Fe/Al records in the north and south of the ZFMB since 2005 CE are mainly controlled by human activities (e.g., human-induced catchment changes in the Changjiang River) and natural climate oscillations (e.g., the East Asian Winter Monsoon and Pacific Decadal Oscillation/Kuroshio Current), respectively. Our study reveals a human-induced asynchronous sedimentary signal in the East China Sea since 2005 CE, and may be applicable to river-dominated marginal seas worldwide during the human-impacted period, providing new evidence to better characterize the Anthropocene epoch. • Natural climate oscillations control the sedimentation processes of the Zhejiang-Fujian mud belt before 2005 CE. •Asynchronous sedimentation processes exist between the north and south of the Zhejiang-Fujian mud belt since 2005 CE. •Human activities cause this asynchronous sedimentary response in space since that time. [ABSTRACT FROM AUTHOR]

• It is essential to utilize diverse sources of observational data for the validation of long-term morphological simulations. • The multiple underlayer settings of the Delft3D model enable its acquisition of decadal bed layer stratigraphy. • Wind and waves sort sediment based on grain size, smoothing out morphological changes induced by tides. • Sea level rise significantly influences regions characterized by intricate morphological features. • Radial sand ridges form under a radial regime with low tidal ellipticity, abundant sand, and minor cohesive sediment. The tidal sand ridges in the southwestern Yellow Sea are unique in the world characterized by radial morphology, significantly higher elevation above low water level, and fine-grained sediment deposits. Using a numerical model, we examined the morphological evolution of the radial sand ridge system from 1979 to 2059. The model was calibrated and validated using hydrodynamic and sediment transport data, seabed topography, and grain size distributions from sediment cores. Our findings reveal that tidal force is the primary driver of the ridges' evolution, and they will continue to expand in response to sediment supply from the abandoned Yellow River delta and the Yangtze delta, with the latter contributing more. The ridges are mainly composed of fine sand and mud, with finer sediment dominating in the north and coarser sediment dominating in the south. Wind and waves sort sediment, depositing sand on ridges and fine sediment in channels, leading to erosion of higher elevated lands and filling of deep channels. Sea-level rise increases regional erosion, which has a large impact on areas with complex morphology. The 500-year morphological evolution of sand ridge systems, simulated through an idealized model, illustrated that the formation of radial sand ridges is dependent upon specific conditions such as the radial tidal regime, sufficient sediment sand, and the presence of cohesive sediment. This study deepens our understanding of the long-term prediction of coastal morphology and interpretation of seabed stratigraphy, and offers insights for effective coastal management. [ABSTRACT FROM AUTHOR]

• Vibrations make a misalignment for Fabry–Pérot cavities in ultra-stable lasers. • Longer than 100 mm cavities in space and recoupling methods have not been reported. • Detection and compensation of misalignment form a loop for actively recoupling. • Recoupling achieved at 0.9 mm and 0.1° misalignment with 0.03 mm and 0.002° error. • The recoupling method is a new idea for handling cavities' misalignment. An active method for coupling a laser with a high-finesse Fabry–Pérot cavity in ultra-stable lasers is proposed. This method uses the centroid of the reflected laser spot and the power ratio of the resonant modes to detect the misalignment between the laser and the Fabry–Pérot cavity. Subsequently, four actively rotating wedge prisms are used to compensate for the misalignment. Based on ray tracing and table lookup, the detection and compensation systems can form a closed loop for actively recoupling the laser into the Fabry–Pérot cavity when a misalignment occurs. Through experiments, the laser can be re-coupled with the Fabry–Pérot cavity by four 0.1° wedge prisms within a 0.9 mm decentration or a 0.1° tilt. The re-alignment of the laser and Fabry–Pérot cavity by active optical coupling may provide an alternative solution for the issue of support and vibration sensitivity of the Fabry–Pérot cavity. This solution is essential to improve the frequency stability of transportable and space-borne ultra-stable lasers. [ABSTRACT FROM AUTHOR]

Abstract: In recent years, the increased pressure of saltwater intrusion in the Modaomen Estuary, one of the outlets in the Pearl River Delta (PRD), China, has threatened the freshwater supply for the surrounding regions. The estuary has complex geometry and bathymetry and branches into three waterways, Madaomen Waterway, Hongwan Waterway, and Hezhou Waterway, entering into the coastal sea. In this study, a three-dimensional baroclinic model (EFDC) was used to investigate salt transport among these branches and saltwater intrusion in the mainstem of the estuary. The salt transport at selected cross sections was decomposed into three components: advection, steady shear, and tidal oscillatory, following the method of Lerczak et al. (Lerczak, J.A., Geyer, W.R., Chant, R.J., 2006. Mechanisms driving the time-dependent salt flux in a partially stratified estuary. Journal of Physical Oceanography 36, 2296–2311). Results from this study indicate that the Hongwan Waterway serves as a salt source for the mainstem of the estuary, especially during spring tides, while the Hezhou Waterway mainly acts as a salt sink for the mainstem. The down-estuary wind increases the steady shear transport in the Modaomen Waterway and the advection transport in the Hongwan Waterway, which alters the saltwater intrusion in the estuary. Closure of the Hongwan and the Hezhou Waterways could result in a 20% decrease of saltwater intrusion in the estuary. These results provide scientific basis for water resource management in the region. [Copyright &y& Elsevier]

Abstract: This paper focuses on the hydrodynamic and suspended sediment transport processes in response to sequential reclamations over the intertidal flat, Jiangsu coast, which used to be one of the widest intertidal flats in China. Investigations into the sediment transport patterns reveal that net suspended sediment fluxes increased from 102 kgm−1 on the upper intertidal flat to 103–4 kgm−1 on the lower intertidal flat, per tidal cycle. This variation was caused mainly by the phases of the current velocity, suspended sediment concentration (SSC), local bed geomorphology, inundation patterns, and extreme weather conditions. The longshore component of tidal currents intensifies seaward over the intertidal flat. Extreme weather conditions (e.g. storms) and strong winds were important factors affecting the current velocity structures, the intensity of residual currents, and the SSCs. The SSCs were characterized by several peaks throughout the tidal cycle. These peaks were associated with strong currents, combined wave-current interactions and intense turbulences due to the initial flood surge. Furthermore, the suspended sediment was finer and contained more clay materials during the flood phase of the tidal cycle, than during the ebb. Fine particles were transported within the upper water column by landward residual currents, but coarse particles were transported within the lower water column by seaward residual currents. Overall, residual currents were apt to transport fine-grained sediment landward and coarse-grained sediment seaward. This pattern indicates that the suspended sediment fluxes are highly variable in the water column, even for very shallow tidal environments. The cross-shore component accounted only for a small percentage of the total sediment flux. However, this part of sediment supply dominated accretion over the intertidal flat. The intertidal flat has become narrower and steeper, following sequential reclamations. A negative feedback process existed to maintain the convex profile shape, although the human activities (i.e. reclamation) could have modified the natural process. The surficial sediment tended to become finer on the mid-upper intertidal flat but coarser on the lower intertidal flat following reclamations, in response to a reduction in the tidal currents over the intertidal zone and enhancement of wave action over the lower intertidal flat. Accretion, with high rates, was maintained by landward transport of sediment. In such an accretional system with influences of reclamation, the width or slope of the intertidal flat is adjusted continuously. Before the cease of reclamation, the intertidal flat is unable to achieve an equilibrium shape. [Copyright &y& Elsevier]

In this study, a Lagrangian particle tracking model driven by hydrodynamic fields was used to investigate the changes of flushing properties in Xiaohai Lagoon resulting from natural evolution and influences of human activities. Comparisons of residence times between 1936 and 2001 indicate that the flushing efficiency of the lagoon has deteriorated greatly during the past seven decades. Over this period, the average residence time of the lagoon has increased from 45 to 71days, an increase of 59%. The Lagrangian residual velocity has decreased from 1936 to 2001 in the large portions of the lagoon, and the spatial distribution pattern of the residual current has changed significantly. The well-developed horizontal circulations in 1936 disappeared. Instead, the horizontal Lagrangian residual velocity showed uniformly seaward motion with reduced velocity in 2001. Human activities have incurred great impacts on the deterioration of flushing efficiency. The reduction of river inflow imposed the most significant impact, causing an increase of average residence time by 33%. The land reclamation in the lagoon came as the second most significant factor, causing an increase of 15%. Closure of the North Opening had posed minor impact. The model results suggest that restoring the river inflow, as well as the dredging of the tidal channel and the inner lagoon, should be the top proprieties for future water quality management. [Copyright &y& Elsevier]

An MIDAS-400 Customised Data Acquisition System was deployed to obtain current velocity and suspended sediment concentration profiles over the intertidal flat at Wanggang, on the Jiangsu coast (China). At the same time, seawater temperature, conductivity and pressure were measured. Using a data sampling rate of 4 Hz, the high-frequency pressure signals in response to water surface fluctuations were recorded and subsequently transformed into wave parameters. The analytical results show that the apparent bed roughness length has a magnitude close to the height of sand ripples, which is much larger than the grain size diameter. The bottom shear stress associated with current-wave interaction is higher than the tidally-induced stress and intensified turbulent mixing and resuspension. Furthermore, several suspended sediment concentration peaks occurred during a tidal cycle, which can be related to strong turbulence near the bed caused by frontal tidal currents and the enhanced resuspension; advection and extreme weather conditions (e. g. storms and strong winds) also played an important role. Finally, large net suspended sediment fluxes were observed to present when the flood or ebb currents prolonged, i.e. the flow became quasi-unidirectional during a tidal cycle. In general, the MIDAS-400 is a suitable tool for high-resolution data collection for the situations of combined current-wave action over intertidal flats; the data obtained can be used to analyze the processes and mechanisms of material transport. [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]

White matter hyperintensity (WMH) is a common finding in aging population and considered to be a contributor to cognitive decline. Our study aimed to characterize the spatial patterns of WMH in different severities and explore its impact on cognition and brain microstructure in non-demented elderly. Lesions were both qualitatively (Fazekas scale) and quantitatively assessed among 321 community-dwelled individuals with MRI scanning. Voxel- and atlas-based analyses of the whole-brain white matter microstructure were performed. The WMH of the same severities was found to occur uniformly with a specific pattern of lesions. The severity of WMH had a significant negative association with the performance of working and episodic memory, beginning to appear in Fazekas 3 and 4. The white matter tracts presented significant impairments in Fazekas 3, which showed brain-wide changes above Fazekas 4. Lower FA in the superior cerebellar peduncle and left posterior thalamic radiation was mainly associated with episodic memory, and the middle cerebellar peduncle was significantly associated with working memory. These results support that memory is the primary domain to be affected by WMH, and the effect may potentially be influenced by tract-specific WM abnormalities. Fazekas scale 3 might be the critical stage predicting a future decline in cognition. [ABSTRACT FROM AUTHOR]

The vertical density gradients of salinity and suspended sediment concentration (SSC) cause stratification in estuaries, which play a vital role in the turbulence structure, water mixing, and sediment transport. To investigate the effect of stratification, especially SSC-induced stratification, on maintaining the estuarine turbidity maximum (ETM), we conducted in situ measurements on sediment dynamics at the upper and central ETM sites in the South Passage of Changjiang Estuary in July 2018. The gradient Richardson number was estimated as a proxy for the stratification that is attributable to salinity or/and SSC. We found that salinity-induced stratification was observed mainly on the surface and in the middle layers, whereas SSC-induced stratification occurred mainly in the near-bottom layers. Furthermore, at the central ETM, the baroclinic effect was enhanced during the neap tide when the salinity-induced stratification was stronger than that during the spring tide. In the early phase of floods with minimum velocity during the neap tide, salinity-induced stratification suppressed the turbulence and vertical diffusion of sediments. Moreover, the flocculation enhanced the settling process within the water column. Consequently, high concentrations of fine-grained sediments formed near the bottom and promoted SSC-induced stratification, thereby leading to the continuous accumulation and trapping of sediments. In conclusion, the interactions among the "salinity- and SSC-induced stratification" processes served as crucial constraints of the temporal and spatial variations of the ETM in the Changjiang Estuary. [ABSTRACT FROM AUTHOR]

Understanding long-term, large cyclone activity is critical for coastal management and disaster prevention and mitigation, particularly with projected rising sea level and increasing cyclone frequency and the intensity. Here we present sedimentary evidence (cyclone overwash deposits, beachrock boulders, and cyclone-induced clastic deposits) of historic large cyclone events from coastal dune deposits on eastern Hainan Island, China. Based on luminescence dating and sedimentological analysis, eight historic tropical cyclone events (at 1095 ± 90 BCE, 900–1000 BCE, 975 ± 50 CE, 1720 ± 20 CE, 1740 ± 35 CE, 1790 ± 25 CE, 1850 ± 15 CE, and 1895 ± 10 CE) have been identified in this region. The elevation of the termination point of cyclone overwash deposit layers that represent the paleo-cyclone minimum wave run-up stage, in combination with knowledge of present-day cyclone events, was applied to assess the intensity of these extreme events. The intensity of these cyclone events was likely greater than that of cyclones in the local instrumental records. Furthermore, these large cyclone events correspond to historic records of devastating cyclones. Through comparison with regional and global climate records, we infer that the variability of large cyclones in the South China Sea was probably modulated by the El Niño-Southern Oscillation, western Pacific warm pool, and local sea surface temperatures over the past 3400 yr. These results provide an improved understanding of long-term, extreme cyclone events and their response to climate change, thereby contributing to regional planning and coastal defense strategies. [ABSTRACT FROM AUTHOR]

Background. The incidence of osteoporotic fractures is increasing. In this study, we explored the activities of Wnt/β-catenin signaling in bone tissues with iron accumulation. Methods. We established rat bipedal walking models (RBWM), and a portion of our RBWM rats were intraperitoneally injected with ferric ammonium citrate, normal saline, and deferoxamine. Bone mineral density was measured with a small animal in vivo imaging system. The protein levels of ferritin, TRAP-5B, RANKL, and OPG in serum were measured by the enzyme-linked immunosorbent assay (ELISA). Quantitative real-time polymerase chain reaction (qRT-PCR) and Western blot were used to quantify the RNA and protein expression levels of certain regulators involved in Wnt/β-catenin signaling in bone tissues. Results. In the present study, we established a rat bipedal walking model containing 32 bipedal rats, which were randomly classified into four groups, termed as NS, FAC, FAC+NS, and FAC+DFO. Those three experimental groups with FAC injection had significantly lower bone mineral density (BMD) than the control group NS (P < 0.05). The disruption of bone homeostasis and downregulation of Wnt/β-catenin signaling were also observed in the three groups with FAC injection. Moreover, after the injection of deferoxamine, those aberrations in samples with FAC injection seemed repaired as test results returning or getting close to normal ranges. Conclusion. The osteoporosis could be caused by iron overload, which reduced the bone mineral density by disrupting the homeostasis of bone formation and absorption and attenuating the Wnt/β-catenin signaling in bone tissues. The deferoxamine had the potential to improve the bone health by reducing the accumulation of iron and increasing the bone mass, which might be a promising therapeutic solution for osteoporosis. [ABSTRACT FROM AUTHOR]

Background: Approximately 80% of adolescent scoliosis cases are idiopathic, and some non-idiopathic scoliosis cases caused by spinal cord abnormalities are misdiagnosed as idiopathic scoliosis. This study examined the risk factors for non-idiopathic scoliosis with intramedullary abnormalities, explored the feasibility of whole-spine MRI, and provided a theoretical basis for the routine diagnosis and treatment of adolescent idiopathic scoliosis.Method: The clinical data of adolescent scoliosis patients who were admitted to Shanghai Tongren Hospital and Shanghai Changhai Hospital between July 1, 2013, and December 31, 2018, were reviewed. According to the whole-spine MRI results, the patients were divided into either the idiopathic group or the intramedullary abnormality group. Sex, age, main curvature angle, main curvature direction, kyphosis angle, scoliosis type, coronal plane balance, sagittal plane balance, abdominal wall reflex, sensory abnormality, ankle clonus and tendon reflexes were compared between the two groups. Student's t test was used to evaluate the differences in the continuous variables, and the chi-square test was used to evaluate the differences in the categorical variables. Fisher's exact test was applied to detect the difference in the rate of intraspinal anomalies between the groups. Logistic regression was used to evaluate the correlation between the multivariate risk factors and intramedullary abnormalities.Result: A total of 714 adolescent scoliosis patients with a mean age of 13.5 (10-18 years) were included in the study, and intramedullary abnormalities were found in 68 (9.5%) patients. There were statistically significant differences in the incidence rates of intramedullary abnormalities between males and females, left and right thoracic curvatures, angular scoliosis and smooth scoliosis, and abnormal abdominal wall reflex and ankle clonus (P < 0.01). Logistic regression showed that the ratios for sex, scoliosis direction, scoliosis type, abdominal wall reflex and ankle clonus were 2.987, 3.493, 4.823, 3.94 and 8.083, respectively. The ROC curve showed a sensitivity of 66.18% and a specificity of 89.01%, and the Youden index corresponding to the optimal critical point was 0.5519.Conclusion: Risk factors associated with adolescent scoliosis caused by abnormal intramedullary abnormalities included male sex, thoracic scoliosis on the left side, sharp curvature of the spine, abnormal abdominal wall reflex and ankle clonus. In adolescent scoliosis patients, the incidence of scoliosis caused by intramedullary abnormalities was approximately 9.5%. These clinical indicators suggest that there is a high-risk adolescent scoliosis population who should undergo whole-spinal MRI preoperatively to rule out intramedullary abnormalities. [ABSTRACT FROM AUTHOR]

The pattern of sediment exchange between the Yangtze River Estuary and the southern Yellow Sea constitutes a crucial yet contentious line of scientific inquiry. This conundrum hampers our comprehensive understanding to predict the future morphological evolution of the radial sand ridges and Jiangsu tidal flats. This study investigates various processes, including tides, wind and waves, to identify the dominant factor controlling sediment exchange between the southern Yellow Sea and the Yangtze River Estuary under storm conditions, using a validated numerical model. Our results show that tide is the dominant force controlling hydrodynamics and sediment transport between the two systems. Tidally induced residual currents and sediment fluxes exhibit a consistent northwesterly trajectory, from the Yangtze River Estuary to the southern Yellow Sea. Conversely, the contributions of wind and wave-induced currents under normal wind conditions (Beaufort Scale 3, 3.4 m s−1) adjust net sediment flux by less than 10 and 46–68%, respectively. In particular, the influence of wind and waves on sediment transport varies significantly with wind direction. While southerly or southeasterly winds amplify the tide-induced northwestward sediment transport, northerly or northeasterly winds curtail it. Under strong winter storm conditions, however, the perturbation caused by northerly winds and waves supersedes the influence of tides in controlling sediment transport, leading to a net residual current and sediment flux oriented southeastwards. • Tide is the dominant force controlling residual currents and sediment transport. • Normally, sediment transport from the Yangtze River Estuary to the southern Yellow Sea. • Northern strong winds and waves revert sediment transport southeastward. • Sediment transports in winter storms are more active nearshore than offshore. [ABSTRACT FROM AUTHOR]

Natural coasts define the interface between land and ocean and constitute a natural barrier to protect humans and infrastructure from waves and storm surges. In the context of global sea level rise and coastal erosion, beaches, especially sand-gravel beaches, can achieve better marine energy reduction at the expense of a smaller spatial buffer zone (i.e., the lateral range of the coastal zone), meaning that nature-based coastal reconstruction and protection are becoming increasingly important. The need for beach replenishment and coastal protection necessitates fast, accurate, portable, and wide-range gravel grain size measurement technology to provide technical support and data for the designing and monitoring of artificial gravel beaches. However, existing grain size analysis methods for gravel-sized sediment are either inefficient (such as sieve analysis) or have a limited range of sizes (such as dynamic image analyzers, up to −3 φ), or have difficulty in eliminating errors caused by gravel overlap (e.g., remote-sensing in situ image analysis). In this study, a Gravel Grain Size and Shape Automatic Measurement System (GraSSAMS) was designed to analyze grain size and shape parameters of gravel-sized sediments. The mean diameters of three types of coins and some Zirconia balls measured using this method were compared with those measured by a vernier caliper. The results show that the GraSSAMS method has good accuracy and yields an acceptable relative error. The grain sizes of 67 field gravel samples were analyzed using both the GraSSAMS method and sieve analysis. The irreducible random error between the two methods is 1.41 φ. In addition, a Camsizer XT and GraSSAMS were used to measure samples with a grain size range of 1∼8 mm (0 φ ∼ -3 φ), respectively. The results of the two methods show good correspondence, with an irreducible random error of 0.31 φ. GraSSAMS was also tested in the field on several gravel beaches. Results revealed that GraSSAMS could complete the surface gravel measurement of a 0.5 m × 0.5 m quadrat within 8 min, and the analysis results avoided the fabric error involved in remote-sensing (photographic) measurement. Based on these various results, we propose that GraSSAMS can be used to analyze the grain size and shape of sand-gravel sediments in the size range of 1∼330 mm (0 φ ∼ -8.37 φ) in a laboratory as well as in the field. Compared with traditional methods, GraSSAM has the advantages of accuracy, high efficiency, and portability and can be used as an alternative for grain size analysis of gravel sediments, with broad application prospects to gravel beaches and fluvial deposits worldwide. We invented an automatic determination system named the Gravel Grain Size and Shape Automatic Measurement System (GraSSAMS) to measure sediment grain size and shape. The GraSSAMS device has controlled machine vision lighting. And the corresponding image-processing procedure was proposed for this method. The GraSSAMS avoids the errors that result from the inclination of individual grains relative to the plane of the image and the partial hiding of grains by others. [Display omitted] • A gravel particle size & shape analysis system (range 1 ∼ 330 mm) is proposed to meet both laboratory and field requirement. • The gravel particles to be measured are dispersed artificially to avoid the error caused by the overlap of field particles. • The photos are of "silhouette type", avoiding the possible misjudgment of image segmentation with an upper light source. • It can be widely used in the design and monitoring of artificial gravel beaches in response to coastal erosion. [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]

An extensive system of tidal channels, starting with Jinshan Trough in the east, is located along the north shore of Hangzhou Bay, China. This contribution investigates the morphological evolution of Jinshan Trough by using 17 bathymetric charts from a series covering a period of 51 years from 1960 to 2011. Three stages of evolution during this period are distinguishable based on the morphology and annual mean volume data. The first stage (1960–1987) is characterized by extension of the trough; the second stage (1987–1996) is a relatively stable period with some adjustments in the trough morphology; the third stage (1996–2011) is marked by the processes of erosion and deposition in the beginning of the period and a subsequent slow erosion process. Spatio-temporal variability of the trough was evaluated by using empirical orthogonal function (EOF) analysis. The first eigenfunction indicates that erosion is the main evolution process and there exists three stages similar to those distinguished from volume variations. The second eigenfunction mainly reflects erosion and deposition in the northwest part of the trough located in the flood tidal current shadow area of the artificial headland in Jinshan. The third eigenfunction mainly reflects annual fluctuations of erosion and deposition in the side slope at the artificial headland in Jinshan. A particularly intense erosion process occurred between 1996 and 1998. The major effects on morphological evolution in Jinshan Trough from 1960 to 2011 were investigated and tentative conclusions were presented. Continuous coastal reclamations in Jinshan had the most pronounced effect on the morphological evolution during the first and the second stages. The storm surge had a pronounced effect on the evolution at the beginning of the third stage. [ABSTRACT FROM AUTHOR]