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Extracts of Radix Cynanchi Auriculati (RCA) have multiple effects. However, it remains unclear whether RCA extracts can exhibit antioxidant activity by regulating MAPKs/Nrf2/HO-1 pathways. In this study, we evaluated the antioxidant activity of ethyl acetate extract of RCA (RCAEA) via LPS-induced RAW264.7 cells, and investigated the potential mechanism of its protective effect against oxidative damage on macrophages. The results showed that RCAEA activating MAPKs/Nrf2/HO-1 pathways. In conclusion, the aim of this study was to describe the molecular mechanisms responsible for the RCAEA mediating the inhibitory effects of oxidative stress in RAW264.7 cells.

The winter–summer transition in the southern South China Sea (SCS) western boundary current (WBC) is studied. Two categories have been identified. In case 1, the southern SCS WBC transition in the lower layer (below the thermocline) lags that in the upper layer (above the thermocline). In case 2, there is no transition lag at full depth. In both categories, the geostrophic balance dominates the transition. In case 1, the upper layer geostrophic balance is dominated by the sea surface height pressure gradient (SSHPG) and Coriolis forcing during southern SCS WBC transition. Therefore, there is no transition lag with depth in the upper layer. Below the thermocline layer, the competition between the SSHPG and the density pressure gradient (DPG) determines the transition. During the transition, the amplitudes of the SSHPG and DPG are basically equivalent. The SSHPG needs time to develop sufficiently larger than the DPG. Therefore, the transition in the deeper layer significantly lags that in the shallower layer. The reversal of the SSHPG is mainly attributed to the change in the basin-scale wind stress curl over the southern SCS. The change in the DPG is mainly associated with the cooling of the water along the western continental slope, which is induced by upwelling. In case 2, there is no cooling along the western continental slope, and then the amplitude of the DPG is always far smaller than that of the SSHPG. Responding to the change in the SSHPG, the southern SCS WBC transition behaves consistently at full depth. Significance Statement We have a comprehensive understanding of the South China Sea (SCS) circulation patterns in winter and summer. However, their seasonal transitions remain unclear, and a better understanding of them is potentially helpful for improving ocean circulation modeling and prediction. This paper focuses on the winter–summer transition in the SCS western boundary current (WBC). Above the thermocline (∼100 m), the transition behaves consistently in the vertical direction and is controlled by the conversion of the sea surface height–induced pressure gradient. Below the thermocline, the transition in the deeper layer of the WBC significantly lags that in the shallower layer of the WBC, which is associated with the competition between the SSH-induced pressure gradient and the density-induced pressure gradient at the sea surface.

Science and technology innovation plays a vital role in the sustainable development of enterprises, and even in the security and sustainable development of a nation. Against the background of China’s structural “deleveraging” macro policy, the following two aspects are considered in this research: First, should operating leverage be removed, and how does it affect the innovation investment of enterprises? Second, what will be the impact of the implementation of equity incentives on the relationship between operating leverage and innovation investment? Using a longitudinal panel dataset of Chinese A-share listed companies from 2010 to 2020, this study empirically tested the impact and mechanism of operating leverage on enterprise innovation investment. The findings show that operating leverage significantly contributes to an increase in enterprise innovation investment in general, but the positive correlation trend decreases with the increase in operating leverage. The implementation of equity incentives plays a positive role in moderating the relationship between operating leverage and innovation investment. Further heterogeneity analysis shows that the promotion effect of operating leverage on innovation investment is significant only in non-state owned enterprises (SOE), and the positive regulating effect of equity incentives in non-SOEs is more significant than that of the overall sample.

Objective. Patients treated with medication for rheumatoid arthritis (RA) often improve but continue to have active diseases. The study aims to investigate whether needle-warming moxibustion (NWM) plus multirehabilitation training can improve quality of life (QoL) and functional mobility of RA patients after medication. Methods. Eighty-four RA patients were selected as study participants, including 42 patients receiving medication (medication group) and 42 patients receiving NWM plus multirehabilitation training (NWM + MRT group). The scores of disease symptoms, pain (visual analogue scale (VAS)), sleep quality (Pittsburgh Sleep Quality Index (PSQI)), functional mobility (Fugl–Meyer assessment scale (FMAS)), self-rating anxiety scale (SAS), self-rating depression scale (SDS), and QoL (SF-36) were compared before and after treatment. When patients were discharged from the hospital, they were given a questionnaire for treatment satisfaction. Results. After treatment, decreases in the scores of the VAS, PSQI, SAS, and SDS were observed in both cohorts, especially in the NWM + MRT group ( P < 0.05 ). The FMAS scores of upper limbs and lower limbs were increased after treatment, which were higher in the NWM + MRT group in comparison with the medication group ( P < 0.05 ). Of note, patients in the NWM + MRT group scored higher in various dimensions of the SF-36 scale ( P < 0.05 ), showing better QoL. The satisfaction survey showed that the NWM + MRT group had a higher proportion of patients being satisfied and a lower proportion of patients being dissatisfied ( P < 0.05 ). Conclusion. NWM plus multirehabilitation training could significantly attenuate disease symptoms, improve QoL, recover functional mobility, and reduce the risk of anxiety and depression in RA patients.

The properties and heat budget of marine heat waves (MHWs) on the northern South China Sea (SCS) continental shelf are investigated. MHWs with warming amplitudes above 1.5°C occur mainly along the coast, and their temperature anomaly decreases toward the open sea. MHWs with 1°–1.5°C warming and duration < 20 days dominate the northern SCS continental shelf. A heat budget analysis indicates that the main heat source is the sea surface net heat flux. Oceanic processes are dominated by the advection of mean temperature by the anomalous horizontal velocity (advha). The net contribution of advha always cools the upper layer of the ocean, resulting in the decay of MHWs. Active cross-slope water exchanges exist at the east and west sides of the northern SCS continental shelf edge, which makes the dominant contributions to the advha. In the MHW developing phase, the west (east) side makes a positive (negative) contribution to the advha. In the decay phase, both sides make a negative contribution to the advha, resulting in the rapid decay of MHWs. Although the contribution of advha to the heat budget varies along the northern SCS continental shelf edge, its net effect always cools the MHWs over the shelf. These results provide new insight into the characteristics and formation mechanism of MHWs on the northern SCS continental shelf; in particular, they clarify the respective contributions of air–sea flux and oceanic processes to MHWs. Significance Statement Marine heat waves (MHWs) are unusual warming events in oceans that heavily affect marine ecosystems and arouse great concern from citizens. MHWs are active in the northern South China Sea (SCS) continental shelf. On the northern SCS continental shelf, the sea surface net heat flux is the main heat source of MHWs, and ocean current anomalies always cool the upper layer of the ocean. Active cross-slope water exchange at the east and west sides of the northern SCS continental shelf edge is the main oceanic way that cools the water on the shelf, eventually resulting in the decay of MHWs.

The responses of surface wind stress to the mesoscale sea surface temperature (SST) anomalies associated with the SST front in the northern South China Sea (NSCS) are studied using satellite observations and reanalysis data. Both satellite and reanalysis data explicitly show the linear relationships between the spatial-high-pass filtered wind stress perturbation derivatives and the underlying SST gradient field. However, the noise in the linear relationships is much smaller in the reanalysis data than in the satellite observations. This result is rarely reported in other frontal areas. The wavelet analysis shows that the satellite scatterometer observed numerous high wavenumber perturbations within 100 km in the NSCS, but these perturbations were absent in the reanalysis data. The linear relationship between the perturbation SST gradient and derivative wind stress fields is not significant at this scale, which enhances the noise in the linear relationship. The spatial bandpass-filtered perturbation between 100 and 300 km can give reasonable estimates of the coupling coefficients between the wind stress divergence and downwind SST gradient (αd) and between the wind stress curl and crosswind SST gradient (αc) in the NSCS, with values of 1.33 × 10−2 and 0.95 × 10−2 N m−2 °C−1, respectively.

The distinct winter temperature difference between the eastern South China Sea (ESCS) and western South China Sea (WSCS) has a crucial impact on regional air–sea interactions. By utilizing satellite and reanalysis data, the zonal contrasting winter thermal conditions and their formation mechanisms are investigated. The second empirical orthogonal function (EOF) mode of winter sea surface temperature (SST) anomalies is responsible for this east–west contrasting temperature pattern (EWCTP), with warming (cooling) in the ESCS (WSCS) and cooling (warming) in the WSCS (ESCS) during the positive (negative) phase events. A mixed layer heat budget analysis reveals that the net heat flux plays a primary role in the WSCS. In the ESCS, the temperature variation is instead mainly dominated by the horizontal heat advection term. In the positive phase events, an anomalous cyclonic circulation promotes an eastern boundary current (EBC) anomaly, which enhances the northward heat transport and thus warms the ESCS. In contrast, an anomalous anticyclonic circulation pattern weakens the heat transport by the southward EBC anomaly and cools the ESCS in the negative phase events. The water exchange through the Mindoro Strait and the vertical entrainment term also contribute to the ESCS SST anomalies. Further analyses show that although there are many EWCTP events that co-occur with the central Pacific El Nino-Southern Oscillation (CP ENSO) events, they have a complex relationship. The EWCTP could appear without CP ENSO events and some CP ENSO events do not lead to the EWCTP. It is because of the different temperature state in the WSCS and ESCS during October–December months and the different contributions of net heat flux and ocean processes to the temperature changes during October–February months.

As an important part of the Indo-Pacific warm pool, the Indian Ocean has great significance for research on the Asian monsoon system and global climate change. From the 1960s onward, several international and regional programs have led to important new insights into the Indian Ocean. The eastern Tropical Indian Ocean Observation Network (TIOON) was established in 2010. The TIOON consists of two parts: large-scope observations and moored measurements. Large-scope observations are performed by the eastern Tropical Indian Ocean Comprehensive Experiment Cruise (TIO-CEC). Moored measurements are executed by the TIOON mooring array and the hydrological meteorological buoy. By 2019, 10 successful TIO-CEC voyages had been accomplished, making this mission the most comprehensive scientific investigation in China. The TIO-CEC voyages have collected temperature/salinity profiles, GPS radiosonde profiles, and other observations in the Indian Ocean. To supplement the existing buoy array in the Indian Ocean, an enhanced TIOON mooring array consisting of eight subthermocline acoustic Doppler current profiler (ADCP) moorings, was established since 2013. The TIOON mooring equipped with both upward-looking and downward-looking WHLS75K ADCP provide valuable current monitoring information to depth of 1,000 m in the Indian Ocean. To improve air–sea interaction monitoring, two real-time hydrological–meteorological buoys were deployed in 2019 and 2020 in the equatorial Indian Ocean. A better understanding of the Indian Ocean requires continuous and long-term observations. The TIOON program and other aspiring field investigation programs will be promoted in the future.

OBJECTIVE: To explore the regulatory role of SOX2-OT in migration of lung squamous cell carcinoma H520 cells and the underlying mechanisms. METHODS: Wound- healing and Transwell migration assays were performed to examine the changes in migration and invasion capacity of lung squamous cell line H520, which expressed higher levels of SOX2-OT than other lung cancer cell lines, following RNA interference-mediated SOX2-OT knockdown. The transcription levels of epithelial-mesenchymal transition (EMT)-related components was detected by qRT-PCR and immunoblotting. Gli1 gain-of-function analysis was performed in H520 cells with SOX2-OT knockdown and the changes in EMT phenotype of the cells were examined. miR-200c mimic and inhibitor were used to analyze the mechanism by which SOX2-OT positively regulates Gli1 and the mediating role of SOX2. RESULTS: SOX2-OT knockdown significantly lowered the invasiveness and migration capacity of H520 cells and caused changes in EMT phenotype of the cells. Overexpression of Gli1, which was positively regulated by SOX2-OT, reversed the inhibitory effect of SOX2-OT knockdown on migration of H520 cells. Transfection of the cells with miR-200c inhibitor effectively reversed SOX2-OT knockdown-induced down-regulation of SOX2. CONCLUSION: The SOX2-OT/SOX2 axis positively regulates migration of lung squamous H520 cells via Gli1-mediated EMT.

The seasonal structure and dynamic mechanism of oceanic surface thermal fronts (STFs) along the western Guangdong coast over the northern South China Sea shelf were analyzed using in situ observational data, remote sensing data, and numerical simulations. Both in situ and satellite observations show that the coastal thermal front exhibits substantial seasonal variability, being strongest in winter when it has the greatest extent and strongest sea surface temperature gradient. The winter coastal thermal front begins to appear in November and disappears after the following April. Although runoff water is more plentiful in summer, the front is weak in the western part of Guangdong. The frontal intensity has a significant positive correlation with the coastal wind speed, while the change of temperature gradient after September lags somewhat relative to the alongshore wind. The numerical simulation results accurately reflect the seasonal variation and annual cycle characteristics of the frontal structure in the simulated area. Based on vertical cross-section data, the different frontal lifecycles of the two sides of the Zhujiang (Pearl) River Estuary are analyzed.

Xuan-qiang Tu,1,* Ze-hua Lai,1,* Yu Zhang,2 Kai-qi Ding,1 Fei-yue Ma,3 Guo-Yuan Yang,1 Ji-rong He,3 Li-li Zeng1 1Department of Neurology and Institute of Neurology, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, People’s Republic of China; 2Department of Neurology and Institute of Neurology, Ruijin Hospital North, School of Medicine, Shanghai Jiao Tong University, Shanghai, People’s Republic of China; 3Department of Neurology and Institute of Neurology, Ruijin Hospital Luwan Branch, Shanghai Jiaotong University School of Medicine, Shanghai, People’s Republic of China*These authors contributed equally to this workCorrespondence: Li-li Zeng No. 197 Ruijin Second Road, Huangpu District, Shanghai, 200025, People’s Republic of ChinaTel +86-13816290607Email llzeng@126.comJi-rong He No. 149 Chongqing South Road, Huangpu District, Shanghai, People’s Republic of ChinaTel +86-13162762045Email kyo3shao@aliyun.comObjective: This study aimed to explore the correlation between white matter hyperintensity (WMH) and post-stroke depression (PSD) at 3 months, and to further investigate sex differences in the pathogenesis of PSD.Methods: A total of 238 consecutive patients with acute cerebral infarction were recruited. PSD was assessed at 2 weeks and at 3 months after stroke onset. All stroke cases were divided into four subgroups according to the diagnosis of depression at two time nodes: continuous depression; depression remission; late-onset PSD; and continuous non-depression. The Fazekas and Scheltens visual rating scales were adopted to assess WMH.Results: Logistic regression revealed that the presence of periventricular white matter hyperintensity (PVWMH) at baseline in male patients was an independent risk factor for PSD at 3 months. Further subgroup analysis revealed that PVWMH was associated with late-onset PSD in males, but not with continuous depression 3 months after stroke. Male acute stroke patients with PVWMH at baseline were more likely to develop PSD at 3 months, especially late-onset PSD.Conclusion: Our data suggest that sex differences may influence the pathogenesis of PSD.Keywords: sex difference, acute cerebral infarction, leukoencephalopathy, affective disorder, post-stroke depression

Background The resistance mechanism of the third generation of epidermal growth factor (EGFR) tyrosine kinase inhibitor (TKI) osimertinib is complex. Epithelial mesenchymal transition (EMT) is a common mechanism of EGFR‐TKI acquired resistance. Snail is an important transcription factor related to EMT. Whether targeting Snail can reverse the resistance of osimertinib by downregulating Snail is unknown. Methods The presence of EMT in H1975/OR (osimertinib resistance) cells was confirmed by transwell assay. To explore the EMT role in resistance, the expression levels of EMT markers were detected in both parental cells H1975 and resistant cells H1975OR. We used RNA interference technology to knockdown the key regulator Snail in resistant cells. After the interference efficiency was confirmed, changes in EMT‐related molecules of Snail were explicitly downregulated, and changes in sensitivity and migration and invasion ability were also examined. We used CDK4/6 inhibitor to test the ability of reversing drug resistance by downregulating Snail. Results Compared with the H1975 cell line, the H1975/OR resistant cell line showed increased invasiveness, upregulated expression of vimentin and downregulation of E‐cadherin. EMT occurred in the H1975/OR resistant cell line. The expression of Snail was upregulated in the osimertinib‐resistant cell line H1975/OR. Knockdown of Snail increased the sensitivity of H1975/OR cells to osimertinib. CDK4/6 inhibitor palbociclib could downregulate the expression of Snail. CDK 4/6 inhibitor palbociclib combined with osimertinib could reverse the resistance of osimertinib in H1975/OR. Conclusions Snail plays an important role in the third generation of EGFR‐TKI osimertinib resistance, which may be reversed by downregulating Snail., In the osimertinib‐resistant cell line H1975/OR, the resistance to Osimertinib and EMT was successfully reversed by downregulating the Snail.

A recently assembled South China Sea Physical Oceanographic Dataset provides the first observational evidence for mixed layer salinity changes in the South China Sea from 1960 to 2015. During this period, the mixed layer waters freshened by 0.22 psu. The mixed layer salinity variability is found to be in sync with the Pacific Decadal Oscillation; it freshened in the 1960s, started to salinify in 1974, freshened again from 1993, and then salinified once again from 2012, with linear trends of − 0.019, 0.020, and − 0.024 psu/year, respectively. A box-average salinity budget analysis shows that the surface forcing, horizontal advection, and vertical entrainment terms together can, to a large degree, explain the observed trend in mixed layer salinity. The mixed layer freshening is driven by weakened surface fresh water loss and saline water transport, while salinification is associated with enhanced surface freshwater loss and salt transport through the Luzon Strait. The long-term mixed layer salinity changes affect the stratification, inducing a thinner mixed layer and stronger barrier layer during freshening periods that favor stronger regional ocean–atmosphere interaction.

Alzheimer's disease (AD) is a progressive neurodegenerative disease most often characterized by memory impairment and cognitive decline. Alpha-asarone has been reported to have the potential to treat AD. Our previous studies have found that alpha-asarone improves aged rats' cognitive function by alleviating neuronal excitotoxicity via type A gamma-aminobutyric acid (GABA) receptors. GABA level's change, neuroinflammation, and dysfunctional autophagy are found to be associated with AD. However, the effect of alpha-asarone on cognitive function of APP/PS1 transgenic mice and its underlying mechanism in terms of aggregation of amyloid-β42 (Aβ42) and phosphorylated tau (p-tau), glutamic acid decarboxylase (GAD) level, neuroinflammation, and autophagy are unclear. Accordingly, we attempted to explore whether alpha-asarone improves AD mice's cognitive function and alleviates pathological symptoms by regulating GAD level, inhibiting neuroinflammation, or restore autophagy. We found that alpha-asarone enhanced spatial learning memory and decreased Aβ42 and p-tau levels without influencing the GAD level in APP/PS1 transgenic mice. Also, it decreased the GFAP expression and reduced pro-inflammatory cytokines levels, thus alleviating neuroinflammation. Furthermore, alpha-asarone decreased the excess number of autophagosomes and promoted hippocampal neurons' survival. In conclusion, the results confirmed the therapeutic effect of alpha-asarone on AD-related astrogliosis, dysfunctional autophagy, and neuronal damage, which indicates its great potential to treat AD.

The third-generation of epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs), represented by osimertinib, has achieved remarkable clinical outcomes in the treatment of non-small-cell lung cancer (NSCLC) with EGFR mutation. However, resistance eventually emerges in most patients and the underlying molecular mechanisms remain to be fully understood. In this study, we generated an osimertinib-acquired resistant lung cancer model from a NSCLC cell line H1975 harboring EGFR L858R and T790M mutations. We found that the capacity of DNA damage repair was compromised in the osimertinib resistant cells, evidenced by increased levels of γH2AX and higher intensity of the comet tail after withdrawal from cisplatin. Pharmacological inhibiting the activity or genetic knockdown the expression of DNA-PK, a key kinase in DNA damage response (DDR), sensitized the resistant cells to osimertinib. Combination of osimertinib with the DNA-PK inhibitor, PI-103, or NU7441, synergistically suppressed the proliferation of the resistant cells. Mechanistically, we revealed that DNA-PK inhibitor in combination with osimertinib resulted in prolonged DNA damage and cell cycle arrest. These findings shed new light on the mechanisms of osimertinib resistance in the aspect of DNA repair, and provide a rationale for targeting DNA-PK as a therapeutic strategy to overcome osimertinib-acquired resistance in NSCLC.

Transition metal phosphide (TMP) based electrocatalysts possessing special crystal and electronic structures attract broad attention in the field of electrocatalysis. Immense effort is made to optimize TMP catalysts aiming to satisfy the electrochemical catalysis performance. In this work, an environmentally friendly in situ green phosphating strategy and spatial limiting effect of the RuCo precursor is employed to fabricate the ruthenium nanoclusters anchored on cobalt phosphide hollow microspheres (Ru NCs/Co2P HMs). The obtained Ru NCs/Co2P HMs electrocatalysts exhibit high hydrogen evolution reaction (HER) activity at wide pH ranges, which require an overpotential of 77 mV to achieve the current density of 10 mA/cm2 in 0.5 mol/L H2SO4 and 118 mV in 1.0 mol/L KOH. Besides, the multifunctional Ru NCs/Co2P HMs exhibit good oxygen evolution reaction (OER) activity with an overpotential of 197 mV to reach the current density of 10 mA/cm2 in 0.5 mol/L H2SO4, which is below that of the commercial RuO2 electrocatalyst (248 mV). A two-electrode electrolyzer is assembled as well, in acid electrolyte, it achieves a current density of 10 mA/cm2 at a voltage of 1.53 V, which is superior to that of the benchmark of precious metal-based electrolyzer (1.58 V).

Many old oilfields have missed or distorted well logs data, which is due to long history of shutdown, poor borehole conditions, damaged instrument, and other reasons. These bring great difficulties to redevelopment of oil and gas field. In this study, a novel method was proposed to complete well logs prediction and quantitative lithology identification. A new model based on gate recurrent unit (GRU) neural network and attention mechanism was constructed in our study. A bidirectional GRU network was designed to extract key features from forward and backward well logs data along depth direction, and attention mechanism was introduced to assign different weights to each hidden layer to improve prediction accuracy. We fully consider the trend of well logs data with depth, the correlation of different log series and the actual depth accumulation effect. Compared with other four traditional intelligent models, experiments on actual reservoir dataset show that the constructed model can obtain lower error and higher fitting degree. Implementation of the proposed method can serve as an economical and reliable alternative for oil and gas industry and provides fast and effective data for further geological research combined with artificial intelligence.

Background The third-generation EGFR-TKI, represented by osimertinib, has been widely used in clinical practice; however, resistance eventually emerges. At present, it remains unclear whether an abnormal cell cycle is involved in acquired resistance, and whether the combination of palbociclib (CDK4/6 inhibitor) and osimertinib can overcome the third-generation TKI resistance. Methods We established osimertinib-resistant cells (H1975 OR) derived from EGFR-mutant NSCLC cells H1975. Drug effects on cells were assessed with Cell Counting Kit-8 (CCK8). Protein alterations were detected with western blot analysis. RT-PCR was used to evaluate the differences of gene mRNA. Cell cycle distribution of H1975 S and H1975 OR cells was compared using flow cytometry. Results Compared with H1975, the sensitivity of H1975OR to the CDK4/6 inhibitor was increased and the proportion of cells in G1 phase was decreased. The mRNA level of CDK4, CDK 6 and the protein level of CDK4, pRB were increased in H1975OR. In the H1975OR cells, palbociclib significantly increased the proportion of G1 phase cells. The combination of osimertinib and palbociclib synergistically decreased the survival of H1975OR by cell cycle arrest. Combined treatment was found to inhibit the initial phosphorylation of RB by inhibiting the function of CDK4/6, significantly reducing the level of p-RB, and blocking cell proliferation. Conclusions An osimertinib acquired resistance cell line (H1975 OR) was successfully established. The expression of cell cycle related genes was altered in H1975OR. The expression of CDK4 and the phosphorylation of Rb, the downstream molecule of CDK4/6, was increased in H1975OR cells. The combination of CDK4/6 inhibitor palbociclib and osimertinib could overcome the acquired resistance of osimertinib.

Fabrication of superior nonprecious electrocatalysts is essential for water electrolysis. Herein, the epitaxial growth of the XMoO4 (X = Ni, Co, Fe) nanosheets on the hexagonal MoO2 nanoplates are ...

Cross-slope flow plays an important role in the exchange of material, heat, and momentum between the continental shelf and the open sea. In the northern South China Sea (SCS), long-period observations confirm that there is significant cross-slope flow. The variability of this flow is dominated by the intraseasonal component (i.e., the 10–90-day period band) that contributes 74.6% of the total standard deviation. The 10–90-day bandpassed cross-slope flow exhibits almost the same direction vertically in the observed layers, and its first empirical orthogonal function, whose direction is also not changed, contributes 86.7% to its total variance. The strong 10–90-day bandpassed cross-slope flow is phase locked to the boreal winter half year. The intraseasonal variability of cross-slope flow is mainly associated with mesoscale eddies west to the Luzon Strait. The contrasting baroclinic instability growth rates, strong in winter and weak in summer, result in a seasonal cycle of mesoscale eddy kinetic energy, that is, vigorous in winter and weak in summer, which explains the winter phase lock. The interannual variability of baroclinic instability growth rate is mainly determined by the vertical shear of velocity. The strongest vertical shear of velocity from 2014 to 2016 occurred in the winter of 2016/17 and induced the most rapid baroclinic instability growth rate and consequently the largest mesoscale eddy kinetic energy, which resulted in the strongest intraseasonal variability of cross-slope flow. The vertical shear of velocity in the northern SCS is mainly determined by the Luzon Strait transport.