Dongxiao Wang - Academia.edu (original) (raw)

Papers by Dongxiao Wang

Nanomedicine : nanotechnology, biology, and medicine, 2016

Heterogenous cancer cells possess cancer multidrug resistance (MDR) due to their relative quiesce... more Heterogenous cancer cells possess cancer multidrug resistance (MDR) due to their relative quiescence and ABC-transporter expression. Heterogenous cancer cells can be detected by an Rh123 exclusion assay for identifying Rh123(low) population. In the present study, we fabricated targeted nanoparticles entrapped with Rh123 (Rh123 NPs) to investigate the effect of these targeted nanoparticles on a Rh123(low) population. The Rh123(low) population stained by Rh123 NPs exhibited similar heterogeneity to that stained by Rh123. In addition, the ABC-transporters did not contribute to the uptake of Rh123 or Rh123 NPs. Interestingly, ABC-transporters in the Rh123(low) population stained by Rh123 were possibly responsible for Rh123 efflux, while Rh123 NPs were not susceptible to ABC-transporters in the Rh123(low) population. It is plausible that the synergistic effect of NPs caused a targeted and endocytic effect which promoted the cellular uptake of Rh123 NPs, and the targeted effect played a m...

Marine Geology, 2014

This study infers, from 2D seismic data, the presence of a seamount-related deep-water contourite... more This study infers, from 2D seismic data, the presence of a seamount-related deep-water contourite depositional system, located on the northwestern margin of the Northwest Sub-Basin of the South China Sea. Alongslope aligned erosive features and contourite drifts developed in water depths between 1000 and 1500 m on the present seafloor. A moat formed north of the seamount as a result of bottom current intensification after being deflected by an obstacle morphology, indicating a major eastward flowing current. Due to the Coriolis deflection, an elongated-mounded drift developed to the north of the moat and a modest plastered drift to the south (onlapping the north side of the seamount). Bottom currents away from the seamount are less or minimally intensified, generating contourite channels and furrows over the drift to the north of the moat. Combined with the known oceanographic setting, the bottom currents could belong to the anticyclonic South China Sea Intermediate Water circulation. From the seismic data, the architecture of contourite deposits during progressive burial of the seamount is documented. The first appearance of contourite channels in seismic Unit 1 is inferred to be the onset of the contourite depositional system, which could be traced back to the early Late Miocene. The following aggradational pattern of this system, from the base of seismic Unit 2 onwards, indicates relatively enhanced and stable South China Sea Intermediate Water circulation occurring on the northwestern margin of the northern South China Sea. Subsequently, the behaviour and depositional processes of bottom currents upstream and downstream the seamount are discussed. The depositional model suggests that a complex contourite channel system will replace the former moat-drift system once the seamount is buried. Finally, our findings may provide new challenges for investigating the South China Sea Cenozoic palaeoceanography, which are helpful to understand the sedimentary dynamic processes related to the South China Sea deepwater circulation.

Pharmaceutical Research, 2014

The complementary strategy by combining targeting ligand-mediated selectivity and CPP-mediated tr... more The complementary strategy by combining targeting ligand-mediated selectivity and CPP-mediated transmembrane function could be exploit synergies for enhancing cellular uptake of nanoparticles with negative charge. A heparin-based nanoparticles with negative charge was fabricated by complementary strategy, which was expected to attain efficient uptake and simultaneously exert great anticancer activity. We synthesized heparin-based nanoparticles with targeting ligand folate and CPP ligand Tat to deliver paclitaxel (H-F-Tat-P NPs). The NPs were characterized by (1)H NMR, DLS and TEM, respectively. The effect of dual ligands on system behavior in aqueous solution was investigated. Moreover, its cellular internalization and anticancer activity were detected by flow cytometry, confocal microscopy and MTT. Folate played a key role in the formation of heparin-based NPs dependent on the balance of amphiphilic Tat and hydrophobic folate. Although H-F-Tat-P NPs primarily entered FR specific and non-specific cells by similar routes, there were no comparability due to cell-type specific variation. Unlike non-specific cells, the complementary ligands could help negative-charged NPs to enhance cellular uptake facilitating its endosome escape in specific cells thereby exhibiting great anticancer activity. The complementary strategy for negative-charged NPs was presented a promising delivery system for diverse anticancer agents enable simultaneously targeting and drug delivery.

Ocean Dynamics, 2012

ABSTRACT The Princeton Ocean Model (POM) with generalized coordinate system (POMgcs) is used to s... more ABSTRACT The Princeton Ocean Model (POM) with generalized coordinate system (POMgcs) is used to study the summer surface-layer thermal response to surface gravity waves in the Yellow Sea (YS). The parameterization schemes of wave breaking developed by Mellor and Blumberg (J Phys Oceanogr 34:693–698, 2004) and Kantha and Clayson (Ocean Model 6:101–124, 2004), respectively, and Stokes production developed by Kantha and Clayson (Ocean Model 6:101–124, 2004) are both included in the Mellor–Yamada turbulence closure model Mellor and Yamada (Rev Geophys 20:851–875, 1982) of POMgcs. Numerical results show that surface gravity waves impact the depth of surface mixed layer of temperature in the YS in summer. The surface mixed layer in the YS cannot be reproduced well and has a visible difference from the observation if the parameterization schemes are not included. A diagnostic analysis of turbulent kinetic energy suggests that both Stokes production and wave breaking play key roles in enhancing the turbulent mixing near the sea surface in the YS. Stokes production seems to have a greater impact throughout the upper mixed layer in the YS in summer than that of wave breaking. In addition, a diagnostic analysis of the momentum balance shows that Coriolis–Stokes forcing has a significant effect on the momentum budget in the upper layer in the YS, and surface gravity waves are able to reduce the velocity of mean flow near the surface and make the mean flow near the surface more homogeneous vertically in the YS.

Journal of Geophysical Research, 2011

Estuarine, Coastal and Shelf Science, 2008

ABSTRACT The variations of current circulation, salt intrusion, and vertical stratification under... more ABSTRACT The variations of current circulation, salt intrusion, and vertical stratification under different river flow and wind conditions in the Pamlico River Estuary (PRE) were investigated in this paper using a three-dimensional numerical model. The model was calibrated and verified against water level variation, temperature, and salinity variations during 2003 and 2001, respectively. Eight sensitivity tests were conducted with different river flow and wind conditions specified in the model. Model results show that salinity intruded further upstream under scenarios with low flow, downriver local wind, and remote-wind-caused water level set-up conditions. In contrast, the responses of salinity stratification to different environmental forcing functions were different in different portions of the estuary. Salinity stratification was enhanced under high flow condition at the lower part of the estuary, under upriver wind near the river mouth, under downriver wind at the upstream to middle portion of the estuary, and under remote-wind-caused water level set-up condition at the majority of the estuary except near the river mouth. Model results also show that across-channel wind tended to reduce salt intrusion and salinity stratification in the PRE through increased vertical mixing.

Aquatic Ecosystem Health & Management, 2012

ABSTRACT Several observations including Argos satellite-tracked drifters, Argo profilers and alti... more ABSTRACT Several observations including Argos satellite-tracked drifters, Argo profilers and altimetry satellite data were analyzed to understand the upper layer circulation in the Luzon Strait. The different role of the wind and the Kuroshio on the Luzon upper layer circulation has been revealed using a reduced gravity model. The observations show that the Kuroshio has a relatively stable pattern with some of Kuroshio water entering the South China Sea in winter. Circulation in the Luzon Strait is mainly controlled by the Kuroshio and the monsoon wind, which have different roles. The Kuroshio could induce a cyclonic gyre west of the Luzon Strait in either summer or winter which is stronger and extends more westward as the Kuroshio becomes stronger. The monsoon wind could drive a cyclonic gyre in the Luzon Strait in summer. In winter, an anticyclonic gyre and a cyclonic gyre are produced southwest of Taiwan Island and northwest of Luzon Island respectively, resulting in a strong westward current in the middle of the Luzon Strait.

Scientific reports, 2016

Energetic fluctuations with periods of 9-14 days below a depth of 1400 m were observed in the sou... more Energetic fluctuations with periods of 9-14 days below a depth of 1400 m were observed in the southern South China Sea (SCS) from 5 years of direct measurements. We interpreted such fluctuations as topographic Rossby waves (TRWs) because they obey the dispersion relation. The TRWs persisted from May 24, 2009 to August 23, 2013, and their bottom current speed with a maximum of ~10 cm/s was one order of magnitude greater than the mean current and comparable to the tidal currents near the bottom. The bottom-trapped TRWs had an approximate trapping depth of 325 m and reference wavelength of ~82 km, which were likely excited by eddies above. Upper layer current speed that peaked approximately every 2 months could offer the energy sources for the persistent TRWs in the southern SCS. Energetic bottom-trapped TRWs may have a comparable role in deep circulation to tides in areas with complex topography.

Scientific reports, 2015

Despite numerous surface eddies are observed in the ocean, deep eddies (a type of eddies which ha... more Despite numerous surface eddies are observed in the ocean, deep eddies (a type of eddies which have no footprints at the sea surface) are much less reported in the literature due to the scarcity of their observation. In this letter, from recently collected current and temperature data by mooring arrays, a deep energetic and baroclinic eddy is detected in the northwestern South China Sea (SCS) with its intensity, size, polarity and structure being characterized. It remarkably deepens isotherm at deep layers by the amplitude of ~120 m and induces a maximal velocity amplitude about 0.18 m/s, which is far larger than the median velocity (0.02 m/s). The deep eddy is generated in a wake when a steering flow in the upper layer passes a seamount, induced by a surface cyclonic eddy. More observations suggest that the deep eddy should not be an episode in the area. Deep eddies significantly increase the velocity intensity and enhance the mixing in the deep ocean, also have potential implicati...

Recent Hurricane Research - Climate, Dynamics, and Societal Impacts, 2011

... over other ocean basins, there are relatively fewer studies in the literature on TC ... exami... more ... over other ocean basins, there are relatively fewer studies in the literature on TC ... examined the Effective Oceanic Layer for Cyclogenesis (EOLC) parameter, which was related with the ... Fung, 2010: Numerical simulation of the genesis of Typhoon Durian (2001) over the South ...

Acta Oceanologica Sinica, 2015

Journal of Geophysical Research: Biogeosciences, 2013

1] Spring bloom is a dominant feature of seasonal phytoplankton cycles in the northwest Atlantic ... more 1] Spring bloom is a dominant feature of seasonal phytoplankton cycles in the northwest Atlantic continental shelf. In this study, we investigate temporal and spatial variations of spring-bloom timing and intensity over the Grand Banks of Newfoundland, using satellite ocean color data and other oceanographic measurements from January 1998 to December 2009. The spring bloom has strong interannual and meridional changes in its timing and intensities. Physical oceanographic conditions including the sea surface temperature (SST), wind speed, and mixed layer depth (MLD) also show evident interannual variations. The spring boom starts first in the southern Bank in February-March and often in the central and northern Bank in April, respectively. An early initiation of spring blooms is generally associated with high SST, weak winds, and shallow MLD at the beginning stage of the spring blooms, and tends to result in stronger intensities. However, the photosynthesis available radiance does not seem to affect the bloom initiation in the southern area or the bloom intensity over the entire Banks. In the southern area, higher SST does not lead to larger bloom magnitude. Our analysis shows that the effect of the SST in the northern area is primarily through the earlier ice melting. It also indicates that Sverdrup's critical depth criteria are suitable for conditions over the Grand Banks. The present study points to the significant sub-bank-scale differences in the timing and magnitude of the spring bloom attributable to underlying physical environments, important for the integrated management of the Grand Banks ecosystem. Citation: Zhao, H., G. Han, and D. Wang (2013), Timing and magnitude of spring bloom and effects of physical environments over the Grand Banks of Newfoundland,

Chinese Journal of Oceanology and Limnology, 2012

ABSTRACT

Journal of Geophysical Research: Oceans, 2014

ABSTRACT Newly available sea surface salinity (SSS) data from the Aquarius together with in-situ ... more ABSTRACT Newly available sea surface salinity (SSS) data from the Aquarius together with in-situ hydrographic data are used to explore the spatial and temporal characteristics of SSS in the South China Sea (SCS). Using in-situ observations as the reference, an evaluation of daily Aquarius data indicates that there exists a negative bias of 0.45 psu for the version 3.0 dataset. The root-mean-square difference for daily Aquarius SSS is about 0.53 psu after correcting the systematic bias, and those for weekly and monthly Aquarius SSSs are 0.45 and 0.29 psu, respectively. Nevertheless, the Aquarius SSS shows a reliable freshening in the SCS in 2012, which is larger than the Aquarius uncertainty. The freshening of up to 0.4 psu in the upper-ocean of the northern SCS was confirmed by in-situ observations. This freshening in 2012 was caused by a combined effect of abundant local freshwater flux and limited Kuroshio intrusion. By comparing the Kuroshio intrusion in 2012 with that in 2011, we found the reduction as a relatively important cause for the freshening over the northern SCS. In contrast to the northern SCS, reduced river discharge in 2012 played the leading role to the saltier surface in the region near the Mekong River mouth with respect to 2011. This article is protected by copyright. All rights reserved.

Climate Dynamics, 2014

This study investigates the impact of the intraseasonal oscillation (ISO) on tropical cyclone (TC... more This study investigates the impact of the intraseasonal oscillation (ISO) on tropical cyclone (TC) tracks in the South China Sea (SCS) during 1970-2010. About one third of TCs in the SCS move eastward, while the other two thirds move westward. In the TC genesis peak seasons of June-October (JJASO), the westward moving TCs are controlled by the background TC steering flow of easterly, and the eastward moving TCs by the TC steering flow induced by the ISO. The outgoing longwave radiation and wind fields show that the eastward moving TCs were mostly along the main axis of strong TC steering flow anomaly of westerly associated with the ISO, while the westward moving TCs were only weakly associated with the ISO. An experiment performed with a simple twolevel model further confirmed the result. The interannual variation of TC tracks in the SCS is also discussed. It is found that the steering flow anomalies in the SCS mostly favor eastward moving TCs in central Pacific (CP) El Niño and eastern Pacific (EP) El Niño years. However, the eastward flow anomalies are too weak to have strong influence on the majority of the TCs. During La Niña years, TCs in the SCS tend to move westward, possibly related to the westward steering flow anomalies.

Journal of Physical Oceanography, 2015

Lagrangian statistics of the surface circulation in the Indian Ocean (IO) are investigated using ... more Lagrangian statistics of the surface circulation in the Indian Ocean (IO) are investigated using drifter observations during 1985-2013. The methodology isolates the influence of low-frequency variations and horizontal shear of mean flow. The estimated Lagrangian statistics are spatially inhomogeneous and anisotropic over the IO basin, with values of ;6-85 3 10 7 cm 2 s 21 for diffusivity, ;2-7 days for integral time scale, and ;33-223 km for length scale. Large diffusivities (.20 3 10 7 cm 2 s 21 ) occur in the central-eastern equatorial IO and the eastern African coast. Small diffusivities (;6-8 3 10 7 cm 2 s 21 ) appear in the subtropical gyre of the southern IO and the southeastern Arabian Sea. The equatorial IO has the largest zonal diffusivity (;85 3 10 7 cm 2 s 21 ), corresponding to the largest time scale (;7 days) and length scale (;223 km), while the eastern coast of Somalia has the largest meridional diffusivity (;31 3 10 7 cm 2 s 21 ). The minor component of the Lagrangian length scale is approximately equal to the first baroclinic Rossby radius (R 1 ) at midlatitudes (R 1 ; 30-50 km), while the major component equals R 1 in the equatorial region (R 1 . 80 km). The periods of the energetic eddy-containing bands in the IO in Lagrangian spectra range from several days to a couple of months, where anticyclones dominate. A significant result is that the drifter-derived diffusivities asymptote to constant values in relatively short time lags (;10 days) for some subregions of the IO if they are correctly calculated. This is an important contribution to the ongoing debate regarding drifter-based diffusivity estimates with relatively short Lagrangian velocity time series versus tracer-based estimates.

Journal of Geophysical Research: Oceans, 2013

1] Sea levels in the southern Indian Ocean (SIO) display significant interannual to decadal varia... more 1] Sea levels in the southern Indian Ocean (SIO) display significant interannual to decadal variability. Off the northwest Australian coast, it has been demonstrated that sea level variability is mostly modulated by remote wind forcing from the tropical Pacific through equatorial and coastal waveguides. In this study, a linear reduced gravity model is used to investigate relative contributions of local wind forcing and remote forcing from the Pacific to the sea level variability of the SIO, with a focus on the western SIO. North of the South Equatorial Current bifurcation latitude (17ºS), model simulated sea levels are well correlated with altimeter observations at the dissipation timescale of about 3 years, suggesting that sea level variability on interannual-to-decadal timescales could well be explained by nondispersive baroclinic Rossby wave adjustment. The large sea level variability of the western SIO is primarily caused by westward-propagating Rossby waves driven by wind stress curl in 70 E-95 E, with a minor influence from the remote Pacific forcing. To the south, sea level variability at around 20ºS displays lower amplitude due to weaker wind variations at this latitude band, and the modeled sea level variability is weaker than observations. There is a close linkage between the cross-basin sea level difference at 15ºS and the interior meridional ocean transport across this latitude on decadal timescales, as assessed with outputs from a data-assimilation model. Thus, the meridional overturning cell of the SIO is influenced by both remote forcing from equatorial Pacific and local winds in the SIO.

The South China Sea is an oligotrophic marginal sea located in the tropical-subtropical Northwest... more The South China Sea is an oligotrophic marginal sea located in the tropical-subtropical Northwestern Pacific Ocean. Under the influences of monsoon winds, both the physical and biogeochemical processes exhibit distinct seasonal variability in the upper waters. In order to study the seasonal variations of surface phytoplankton, a one-dimensional coupled physical-biogeochemical model was developed and applied to the deep basins of

We deployed two ADCP mooring systems west of the Luzon Strait in August 2008, and measured the up... more We deployed two ADCP mooring systems west of the Luzon Strait in August 2008, and measured the upper ocean currents at high frequency. Two typhoons passed over the moorings during approximately one-month observation period. Using ADCP observations, satellite wind and heat flux measurements, and high-resolution model assimilation products, we studied the response of the upper ocean to typhoons. The first typhoon, Nuri, passed over one of the moorings, resulting in strong Ekman divergence and significant surface cooling. The cooling of surface water lagged the typhoon wind forcing about one day and lasted about five days. The second typhoon, Sinlaku, moved northward east of the Luzon Strait, and did not directly impact currents near the observation regions. Sinlaku increased anomalous surface water transport exchange across the Luzon Strait, which modulated the surface layer current of the Kuroshio.