Silencing of the long non-coding RNA LINC00265 triggers autophagy and apoptosis in lung cancer by reducing protein stability of SIN3A oncogene

Background:Long non-coding RNAs are important regulators in cancer biology and function either as tumor suppressors or as oncogenes.Their dysregulation has been closely associated with tumorigenesis.LINC00265 is upregulated in lung adenocarcinoma and is a prognostic biomarker of this cancer.However,the mechanism underlying its function in cancer progression remains poorly understood.Methods:Here,the regulatory role of LINC00265 in lung adenocarcinoma was examined using lung cancer cell lines,clinical samples,and xenografts.Results:We found that high levels of LINC00265 expression were associated with shorter overall survival rate of patients,whereas knockdown of LINC00265 inhibited proliferation of cancer cell lines and tumor growth in xenografts.Western blot andflow cytometry analyses indicated that silencing of LINC00265 induced autophagy and apoptosis.Moreover,we showed that LINC00265 interacted with and stabilized the transcriptional co-repressor Switch-independent 3a(SIN3A),which is a scaffold protein functioning either as a tumor repressor or as an oncogene in a context-dependent manner.Silencing of SIN3A also reduced proliferation of lung cancer cells,which was correlated with the induction of autophagy.These observations raise the possibility that LINC00265 functions to promote the oncogenic activity of SIN3A in lung adenocarcinoma.Conclusions:Ourfindings thus identify SIN3A as a LINC00265-associated protein and should help to understand the mechanism underlying LINC00265-mediated oncogenesis.

Multiscale Combined Action and Disturbance Characteristics of Pre-summer Extreme Precipitation Events over South China

The dominant frequency modes of pre-summer extreme precipitation events(EPEs)over South China(SC)between1998 and 2018 were investigated.The 67 identified EPEs were all characterized by the 3-8-d(synoptic)frequency band.However,multiscale combined modes of the synoptic and three low-frequency bands[10-20-d(quasi-biweekly,QBW);15-40-d(quasi-monthly,QM);and 20-60-d(intraseasonal)]accounted for the majority(63%)of the EPEs,and the precipitation intensity on the peak wet day was larger than that of the single synoptic mode.It was found that EPEs form within strong southwesterly anomalous flows characterized by either lower-level cyclonic circulation over SC or a deep trough over eastern China.Bandpass-filtered disturbances revealed the direct precipitating systems and their life cycles.Synoptic-scale disturbances are dominated by mid-high latitude troughs,and the cyclonic anomalies originate from downstream of the Tibetan Plateau(TP).Given the warm and moist climate state,synoptic-scale northeasterly flows can even induce EPEs.At the QBW and QM scales,the disturbances originate from the tropical Pacific,downstream of the TP,or mid-high latitudes(QBW only).Each is characterized by cyclonic-anticyclonic wave trains and intense southwesterly flows between them within a region of large horizontal pressure gradient.The intraseasonal disturbances are confined to tropical regions and influence SC by marginal southwesterly flows.It is concluded that low-frequency disturbances provide favorable background conditions for EPEs over SC and synoptic-scale disturbances ultimately induce EPEs on the peak wet days.Both should be simultaneously considered for EPE predictions over SC.

Modulation of the Wind Field Structure of Initial Vortex on the Relationship between Tropical Cyclone Size and Intensity

This study investigates the modulation of initial wind field structure on the relationship between the size and intensity of a simulated vortex.A series of idealized experiments are conducted by varying the radius of maximum wind(RMW)and shape parameter of the initial vortices.The size–intensity relationship is quantified by the linear regression coefficient of the azimuthally-averaged gale-force wind radius against the maximum wind during the development stage,reflecting the degree of size expansion at the same intensity increment.The regression coefficient increases with increased RMW and decreased,with the RMW being the primary constraint.The effect of lowering on the elevation of the regression coefficient gradually stands out when the initial RMW is large.Enlarging the RMW leads to a secondary circulation with a horizontally elongated structure,which retards the intensification while promoting size expansion,thus substantially enhancing size expansion as the vortex intensifies.Broadening the wind field outside the RMW by reducing results in abounding convection in the outer region,which promotes size expansion.Based on the axisymmetric tangential wind tendency and Sawyer–Eliassen equations,when the RMW is large,the active convection in the outer region can weaken the radial inflow induced by the eyewall heating in the inner region,thus retarding the intensification by reducing the radial imports of vorticity near the RMW.

Circulation Features Associated with the Record-breaking Typhoon Silence in August 2014

Climatologically, August is the month with the most tropical cyclone(TC) formation over the western North Pacific(WNP) during the typhoon season. In this study, the reason for abnormal TC activity during August is discussed—especially August 2014, when no TCs formed. The large-scale background of August 2014 is presented, with low-level large-scale easterly anomalies and anticyclonic anomalies dominating over the main TC genesis region, a weak monsoon trough system,and a strong WNP subtropical high(WPSH), leading to significantly reduced low-level convergence, upper-level divergence,and mid-level upward motion. These unfavorable large-scale conditions suppressed convection and cyclogenesis. In August2014, equatorial waves were inactive within the negative phase of the Madden–Julian Oscillation(MJO), with fewer tropical disturbances. Although the low-level vorticity and convection of those disturbances were partly promoted by the convective envelopes of equatorial waves, the integral evolution of disturbances, as well as the equatorial waves, were suppressed when propagating into the negative MJO phase. Moreover, the upper-level potential vorticity(PV) streamers associated with anticyclonic Rossby wave breaking events imported extratropical cold and dry air into the tropics. The peripheral tropospheric dryness and enhanced vertical wind shear by PV streamer intrusion combined with the negative MJO phase were responsible for the absence of TC formation over the WNP in August 2014.

Boosting proso millet yield by altering canopy light distribution in proso millet/mung bean intercropping systems

To elucidate the mechanism by which intercropping proso millet(Panicum miliaceum L.)with mung bean(Vigna radiata L.)increases proso millet yield and to determine how this higher yield results from maximization of resources use efficiency,we designed and conducted four strip intercropping row arrangements,including two rows of proso millet alternating with two rows of mung bean(2P2M),four rows of proso millet alternating with two rows of mung bean(4P2M),four rows of proso millet alternating with four rows of mung bean(4P4M),two rows of proso millet alternating with four rows of mung bean(2P4M),sole proso millet(SP,control)and sole mung bean(SM,control)in Yulin,Shaanxi,China.Photosynthetically active radiation(PAR)in the canopy,radiation use efficiency(RUE),leaf photosynthetic characteristics,dry matter accumulation and allocation,and yield of proso millet were investigated.The results showed that the intercropping systems had higher PAR than the monoculture.Mean PAR intensities were increased by respectively 2.2%–23.4%,19.8%–59.7%,and 61.2%–133.3%in the proso millet upper,middle and lower canopies compared with SP.The increase in PAR directly increased RUE,a result attributed mainly to the increase in photosynthetic capacity,including net photosynthetic rate and chlorophyll content.These responses resulted in increased dry matter allocation to plant organs.Yield of intercropped proso millet was 6.8%–37.3%higher than that under monoculture and the land equivalent ratios for the different intercropping patterns were all greater than unity(>1).In general,yield followed a positive linear function of PAR in the intercropping system.The results indicated that intercropping can boost proso millet yield,evidently by altering light distribution within its canopy and consequently increasing RUE,thereby increasing leaf photosynthetic capacity,dry matter accumulation,and allocation to the grain.The optimum combination for improving the growth and yield of proso millet on the Loess Plateau of China was 2P4M.

Impact of the Spring SST Gradient between the Tropical Indian Ocean and Western Pacific on Landfalling Tropical Cyclone Frequency in China

The present study identifies a significant influence of the sea surface temperature gradient（SSTG） between the tropical Indian Ocean（TIO; 15°S-15°N, 40°-90°E） and the western Pacific warm pool（WWP; 0°-15°N, 125°-155°E） in boreal spring on tropical cyclone（TC） landfall frequency in China's Mainland in boreal summer. During the period 1979-2015, a positive spring SSTG induces a zonal inter-basin circulation anomaly with lower-level convergence, mid-tropospheric ascendance and upper-level divergence over the west-central TIO, and the opposite situation over the WWP, which produces lower-level anomalous easterlies and upper-level anomalous westerlies between the TIO and WWP. This zonal circulation anomaly further warms the west-central TIO by driving warm water westward and cools the WWP by inducing local upwelling, which facilitates the persistence of the anomaly until the summer. Consequently, lower-level negative vorticity, strong vertical wind shear and lower-level anticyclonic anomalies prevail over most of the western North Pacific（WNP）, which decreases the TC genesis frequency. Meanwhile, there is an anomalous mid-tropospheric anticyclone over the main WNP TC genesis region,meaning a westerly anomaly dominates over coastal regions of China's Mainland, which is unfavorable for steering TCs to make landfall in China's Mainland during summer. This implies that the spring SSTG may act as a potential indicator for TC landfall frequency in China's Mainland.

Evaluation of Two Initialization Schemes for Simulating the Rapid Intensification of Typhoon Lekima (2019)

Two different initialization schemes for tropical cyclone(TC)prediction in numerical models are evaluated based on a case study of Typhoon Lekima(2019).The first is a dynamical initialization(DI)scheme where the axisymmetric TC vortex in the initial conditions is spun up through the 6-h cycle runs before the initial forecast time.The second scheme is a bogussing scheme where the analysis TC vortex is replaced by a synthetic Rankine vortex.Results show that although both initialization schemes can help improve the simulated rapid intensification(RI)of Lekima,the simulation employing the DI scheme(DIS)reproduces better the RI onset and intensification rate than that employing the bogussing scheme(BOG).Further analyses show the cycle runs of DI help establish a realistic TC structure with stronger secondary circulation than those in the control run and BOG,leading to fast vortex spinup and contraction of the radius of maximum wind(RMW).The resultant strong inner-core primary circulation favors precession of the midlevel vortex under the moderate vertical wind shear(VWS)and thus helps vortex alignment,contributing to an earlier RI onset.Afterwards,the decreased vertical shear and the stronger convection inside the RMW support the persistent RI of Lekima in DIS.In contrast,the reduced VWS is not well captured and the inner-core convection is weaker and resides farther away from the TC center in BOG,leading to slower intensification.The results imply that the DI effectively improves the prediction of the inner-core process,which is crucial to the RI forecast.

Impact of Interannual Variation of Synoptic Disturbances on the Tracks and Landfalls of Tropical Cyclones over theWestern North Pacific

This study investigates the tropical cyclone(TC)activity associated with the two leading modes of interannual variability in synoptic disturbances.Both leading modes are found to be related to a dipole pattern of TC occurrence between the subtropical western North Pacific and the South China Sea.Therefore,in this study we performed composite analyses on TC tracks and landfalls,based on the cases of combined modes,to highlight the differences.The composite results indicate that these cases are characterized by distinct features of TC tracks and landfalls:more TCs tend to take recurving tracks and attack eastern China,Korea and Japan,or more TCs exhibit straight-moving tracks and hit the Philippines,Vietnam and southern China.Further analyses suggest that these distinctions in the TC prevailing tracks and landfalls can be attributed to the differences in large-scale steering flow and TC genesis location.

Intensified Impact of Northern Tropical Atlantic SST on Tropical Cyclogenesis Frequency over the Western North Pacific after the Late 1980s

Previous studies suggest that spring SST anomalies over the northern tropical Atlantic（NTA） affect the tropical cyclone（TC） activity over the western North Pacific（WNP） in the following summer and fall. The present study reveals that the connection between spring NTA SST and following summer–fall WNP TC genesis frequency is not stationary. The influence of spring NTA SST on following summer–fall WNP TC genesis frequency is weak and insignificant before, but strong and significant after, the late 1980 s. Before the late 1980 s, the NTA SST anomaly-induced SST anomalies in the tropical central Pacific are weak, and the response of atmospheric circulation over the WNP is not strong. As a result, the connection between spring NTA SST and following summer–fall WNP TC genesis frequency is insignificant in the former period. In contrast,after the late 1980 s, NTA SST anomalies induce pronounced tropical central Pacific SST anomalies through an Atlantic–Pacific teleconnection. Tropical central Pacific SST anomalies further induce favorable conditions for WNP TC genesis,including vertical motion, mid-level relative humidity, and vertical zonal wind shear. Hence, the connection between NTA SST and WNP TC genesis frequency is significant in the recent period. Further analysis shows that the interdecadal change in the connection between spring NTA SST and following summer–fall WNP TC genesis frequency may be related to the climatological SST change over the NTA region.

Reexamination of the Relationship between Tropical Cyclone Size and Intensity over the Western North Pacific

This study reexamines the correlation between the size and intensity of tropical cyclones(TCs) over the western North Pacific from the perspective of individual TCs, rather than the previous large-sample framework mixing up all TC records.Statistics show that the positive size-intensity correlation based on individual TCs is relatively high. However, this correlation is obscured by mixing large samples. The weakened correlation based on all TC records is primarily due to the diversity in the size change relative to the same intensity change among TCs, which can be quantitatively measured by the linear regression coefficient(RC) of size against intensity. To further explore the factors that cause the variability in RCs that weakens the size-intensity correlation when considering all TC records, the TCs from 2001 to 2020 are classified into two groups according to their RC magnitudes, within which the high-RC TCs have a larger size expansion than the low-RC TCs given the same intensity change. Two key mechanisms responsible for the RC differences are proposed. First, the highRC TCs are generally located at higher latitudes than the low-RC TCs, resulting in higher planetary vorticity and thus higher planetary angular momentum import at low levels. Second, the high-RC TCs are susceptible to stronger environmental vertical wind shear, leading to more prolific outer convection than the low-RC TCs. The positive feedback between outer diabatic heating and boundary layer inflow favors the inward import of absolute angular momentum in the outer region, thereby contributing to a larger size expansion in the high-RC TCs.

Interannual Variations in Synoptic-Scale Disturbances over the Western North Pacific

The present study investigates the interannual variation of June-November synoptic disturbance activity over the western North Pacific（WNP） and its relationship with large-scale circulation for the period 1958-2014. Two leading modes of eddy kinetic energy for the disturbance variability over the WNP are obtained by EOF analysis, characterized by anomalous eddy kinetic energy over the subtropical WNP and around the Philippines, respectively. These modes explain a large portion of the interannual variance of synoptic disturbance activity over the WNP. Both are associated with lower-level cyclonic anomalies, but with different locations： over the subtropical WNP for the first mode and over the South China Sea for the second mode. Considering the impact of ENSO on synoptic disturbance activity over the WNP, we repeat the analyses after removing the effect of ENSO, which is simply defined as the components linearly regressed onto the Ni o3.4 index, and find similar results, suggesting that the leading modes and their relationships with large-scale circulation exist without SST effects.Further analyses suggest that the meridional shear of zonal winds caused by cyclonic anomalies is crucial for maintaining the leading modes through barotropic conversion.

Determination of the Effect of Initial Inner-Core Structure on Tropical Cyclone Intensification and Track on a Beta Plane

The sensitivity of TC intensification and track to the initial inner-core structure on a β plane is investigated using a numerical model. The results show that the vortex with large inner-core winds（CVEX-EXP） experiences an earlier intensification than that with small inner-core winds（CCAVE-EXP）, but they have nearly the same intensification rate after spin-up. In the early stage, the convective cells associated with surface heat flux are mainly confined within the inner-core region in CVEXEXP, whereas the vortex in CCAVE-EXP exhibits a considerably asymmetric structure with most of the convective vortices being initiated to the northeast in the outer-core region due to the β effect. The large inner-core inertial stability in CVEX-EXP can prompt a high efficiency in the conversion from convective heating to kinetic energy. In addition, much stronger straining deformation and PBL imbalance in the inner-core region outside the primary eyewall ensue during the initial development stage in CVEX-EXP than in CCAVE-EXP, which is conducive to the rapid axisymmetrization and early intensification in CVEX-EXP. The TC track in CVEX-EXP sustains a northwestward displacement throughout the integration, whereas the TC in CCAVE-EXP undergoes a northeastward recurvature when the asymmetric structure is dominant. Due to the enhanced asymmetric convection to the northeast of the TC center in CCAVE-EXP, a pair of secondary gyres embedded within the large-scale primary β gyres forms, which modulates the ventilation flow and thus steers the TC to move northeastward.

Relationship of tropical cyclone size change rate with size and intensity over the western North Pacific

In this study,the relationship of tropical cyclone(TC)size change rate(SCR),within 24 hours,with size,intensity,and intensity change rate(ICR)are explored over the western North Pacific.TC size is defined as the azimuthally averaged radius of gale-force wind of 17 m s−1(R17)based on the Multiplatform Tropical Cyclone Surface Winds Analysis data.The majority of SCRs are mainly distributed in the range from−20 to 80 km d−1.The correlation coefficients between SCR and size(SCR-R17),intensity,and ICR(SCR-ICR)are−0.43,−0.12,and 0.25,respectively.The sensitivity of the SCR-R17 and SCR-ICR relationships to size,intensity,and evolution stage are further examined.Results show that the SCR-R17 relationship is more sensitive to variations of size and evolution stage than that of intensity.The relationship of SCR-ICR is largely modulated by the evolution stage.The correlation coefficient of SCR-ICR can increase from 0.25 to 0.40 when only considering the lifetime stages concurrently before and after the lifetime maximum size(LMS)and lifetime maximum intensity.This demonstrates that ICR is a potential factor in predicting SCR during these evolution stages.Besides,the TC size expansion(shrinkage)is more likely to occur for TCs with smaller(larger)size and weaker(stronger)intensity.The complexity of size change during a TC's lifetime can be attributed to the fact that shrinkage or expansion could occur both before and after LMS.

A review of recent research progress on the effect of external influences on tropical cyclone intensity change

Over the past four years,significant research has advanced our understanding of how external factors influence tropical cyclone(TC)intensity changes.Research on air-sea interactions shows that increasing the moisture disequilibrium is a very effective way to increase surface heatfluxes and that ocean salinity-stratification plays a non-negligible part in TC intensity change.Vertical wind shear from the environment induces vortex misalignment,which controls the onset of significant TC intensification.Blocking due to upper-level outflow from TCs can reduce the magnitude of vertical wind shear,making for TC intensification.Enhanced TC-trough interactions are vital for rapid intensification in some TC cases because of strengthened warm air advection,but upper-level troughs are found to limit TC intensification in other cases due to dry midlevel air intrusions and increased shear.Aerosol effects on TCs can be divided into direct effects involving aerosol-radiation interactions and indirect effects involving aerosol-cloud interactions.The radiation absorption by the aerosols can change the temperature profile and affect outer rainbands through changes in stability and microphysics.Sea spray and sea salt aerosols are more important in the inner region,where the aerosols increase precipitation and latent heating,promoting more intensification.For landfalling TCs,the intensity decay is initially more sensitive to surface roughness than soil moisture,and the subsequent decay is mainly due to the rapid reduction in surface moisturefluxes.These new insights further sharpen our understanding of the mechanisms by which external factors influence TC intensity changes.