Dynamic simulation insights into friction weakening effect on rapid long-runout landslides:A case study of the Yigong landslide in the Tibetan Plateau,China

This study proposed a novel friction law dependent on velocity,displacement and normal stress for kinematic analysis of runout process of rapid landslides.The well-known Yigong landslide occurring in the Tibetan Plateau of China was employed as the case,and the derived dynamic friction formula was included into the numerical simulation based on Particle Flow Code.Results showed that the friction decreased quickly from 0.64(the peak)to 0.1(the stead value)during the 5s-period after the sliding initiation,which explained the behavior of rapid movement of the landslide.The monitored balls set at different sections of the mass showed similar variation characteritics regarding the velocity,namely evident increase at the initial phase of the movement,followed by a fluctuation phase and then a stopping one.The peak velocity was more than 100 m/s and most particles had low velocities at 300s after the landslide initiation.The spreading distance of the landslide was calculated at the two-dimension(profile)and three-dimension scale,respectively.Compared with the simulation result without considering friction weakening effect,our results indicated a max distance of about 10 km from the initial unstable position,which fit better with the actual situation.

某航空大学飞行学员对比度远视力的影响因素分析

目的:记录并调查某航空大学飞行学员在理论学习阶段对比度远视力以及用眼习惯,分析飞行学员对比度远视力变化情况与用眼习惯影响因素的关系。方法:记录并分析某航空大学理论学习阶段一年级及二年级期末飞行学员对比度远视力,并采用问卷调查方式对用眼习惯进行记录分析。结果:总计对117名一年级飞行学员、210名二年级飞行学员进行对比度远视力检查,其中双眼视力均在1.0以上者一年级为83人(70.9%)、二年级为174人(82.9%)(P<0.05)。对上述学员进行用眼习惯的问卷调查:一、二年级飞行学员每日阅读学习时间≤6h者分别为87.2%、93.3%,每日运动时间≤2h者分别为34.2%、13.8%,采用综合运动者分别为57.3%、90.0%,每日使用电子产品≤2h分别为38.5%、43.3%,夜间曾使用电子产品者分别为85.5%、75.7%,对健康用眼知识知晓情况分别为61.5%、81.0%(P<0.05)。结论:航空大学理论学习阶段的飞行学员对比度远视力略有提高,主要与理论学习阶段阅读时间减少、户外运动时间增加、运动方式改善、电子产品使用时间减少及用眼知识加强因素相关。

A Review on Graphene-Based Gas/Vapor Sensors with Unique Properties and Potential Applications

Graphene-based gas/vapor sensors have attracted much attention in recent years due to their variety of structures, unique sensing performances, room-temperature working conditions, and tremendous application prospects, etc.Herein, we summarize recent advantages in graphene preparation, sensor construction, and sensing properties of various graphene-based gas/vapor sensors, such as NH_3, NO_2, H_2, CO, SO_2, H_2S, as well as vapor of volatile organic compounds.The detection mechanisms pertaining to various gases are also discussed. In conclusion part, some existing problems which may hinder the sensor applications are presented. Several possible methods to solve these problems are proposed, for example, conceived solutions, hybrid nanostructures, multiple sensor arrays, and new recognition algorithm.

γδ T Cells Contribute to the Outcome of Murine Fulminant Viral Hepatitis via Effector Cytokines TNF-α and IFN-γ

The mechanisms involved in virus-induced severe hepatitis have not been fully elucidated. In this study, we investigated the role of gamma delta T cell receptors （γδ） T cells in the pathogenesis of fulminant viral hepatitis （FVH） induced by murine hepatitis virus strain 3 （MHV-3）. The model of FVH was established by intraperitoneal injection of MHV-3 into Balb/cJ mice. The survival days of mice, and the serum levels of alanine aminotransferase （ALT） and aspartate aminotransferase （AST） were examined. The proportions of γδ T cells in blood, spleen and liver, and cytokines secreted by hepatic γδ T cells were analyzed by flow cytometry. The function of hepatic γδ T cells was examined by cytotoxicity assay. Balb/cJ mice died in 3 to 6 days post MHV-3 infection, with severe hepatic necrosis and significant augmentation of serum ALT and AST levels. The proportions of γδ T cells in blood, spleen and liver were significantly increased post MHV-3 infection, while those of the early activating molecule CD69-expressing γδ T cells and productions of cytokines tumor necrosis factor-alpha （TNF-α） and interferon-y （IFN-3,） increased remarkably in the liver. These highly activated liver γδ T cells were cytotoxic to MHV-3-infected hepatocytes in vitro and this effect of liver γδ T cells against hepatocytes might involve the TNF-α and IFN-γ pathway. These results demonstrated that γδ T cells might contribute to the pathogenesis of MHV-3-induced FVH through the effector cytokines TNF-α and IFN-γ. Key words： fulminant viral hepatitis; murine hepatitis virus strain 3; gamma delta T cell receptors T cells; tumor necrosis factor-a; interferon-α

In situ studies on the positive and negative effects of 1,8-diiodoctane on the device performance and morphology evolution of organic solar cells

The introduction of solvent additives is one of the most common approaches for enhancing the power conversion efficiency of organic solar cells(OSCs).However,the use of solvent additives has some negative effects,and an understanding of how solvent additives affect OSCs is currently limited.In this study,we developed an in situ grazing incidence wide-angle X-ray scattering(GIWAXS)technique in the SAXS beamline(BL16 B1)at the Shanghai Synchrotron Radiation Facility,and the additive effects of1,8-diiodoctane(DIO)on the performance and morphology evolution of the PTB7-Th/PC71 BM device was investigated in depth.The results revealed that the crystal size increased with the volume ratio of DIO,and a drastic evolution of lattice space and crystal coherence length was observed during thermal annealing for the first time,to our knowledge.The discrete PC71BM molecules dissolved by DIO have an effect similar to that of the nucleating agent for PTB7-Th,boosting the crystallization of PTB7-Th,reducing phase separation,and inducing more drastic morphological evolution during thermal annealing.Our results provide a deep perspective for the mechanism of solvent additives,while also showing the significance and feasibility of the in situ GIWAXS technique we developed at BL16 B1.

Experimental and Numerical Study on the Shear Strength and Strain Energy of Rock Under Constant Shear Stress and Unloading Normal Stress

Excavation and earth surface processes(e.g.,river incision)always induce the unloading of stress,which can cause the failure of rocks.To study the shear mechanical behavior of a rock sample under unloading normal stress conditions,a new stress path for direct shear tests was proposed to model the unloading of stress caused by excavation and other processes.The effects of the initial stresses(i.e.,the normal stress and shear stress before unloading)on the shear behavior and energy conversion were investigated using laboratory tests and numerical simulations.The shear strength of a rock under constant stress or under unloading normal stress conforms to the Mohr Coulomb criterion.As the initial normal stress increases,the cohesion decreases linearly and the tangent of the internal friction angle increases linearly.Compared with the results of the tests under constant normal stress,the cohesions of the rock samples under unloading normal stress are smaller and their internal friction angles are larger.A strength envelope surface can be used to describe the relationship between the initial stresses and the failure normal stress.Shear dilatancy can decrease the total energy of the direct shear test under constant normal stress or unloading normal stress,particularly when the stress levels(the initial stresses in the test under unloading normal stress or the normal stress in the test under constant normal stress)are high.The ratio of the dissipated energy to the total energy at the moment failure occurs decreases exponentially with increasing initial stresses.The direct shear test under constant normal stress can be considered to be a special case of a direct shear test under unloading normal stress with an unloading amount of zero.

Shallow landslide susceptibility assessment under future climate and land cover changes: A case study from southwest China

There is no doubt that land cover and climate changes have consequences on landslide activity,but it is still an open issue to assess and quantify their impacts.Wanzhou County in southwest China was selected as the test area to study rainfall-induced shallow landslide susceptibility under the future changes of land use and land cover(LULC)and climate.We used a high-resolution meteorological precipitation dataset and frequency distribution model to analyse the present extreme and antecedent rainfall conditions related to landslide activity.The future climate change factors were obtained from a 4-member multimodel ensemble that was derived from statistically downscaled regional climate simulations.The future LULC maps were simulated by the land change modeller(LCM)integrated into IDRISI Selva software.A total of six scenarios were defined by considering the rainfall(antecedent conditions and extreme events)and LULC changes towards two time periods(mid and late XXI century).A physically-based model was used to assess landslide susceptibility under these different scenarios.The results showed that the magnitude of both antecedent effective recharge and event rainfall in the region will evidently increase in the future.Under the scenario with a return period of 100 years,the antecedent rainfall in summer will increase by up to 63%whereas the event rainfall will increase by up to 54%for the late 21st century.The most considerable changes of LULC will be the increase of forest cover and the decrease of farming land.The magnitude of this change can reach+22.1%(forest)and–9.2%(farmland)from 2010 until 2100,respectively.We found that the negative impact of climate change on landslide susceptibility is greater than the stabilizing effect of LULC change,leading to an over decrease in stability over the study area.This is one of the first studies across Asia to assess and quantify changes of regional landslide susceptibility under scenarios driven by LULC and climate change.Our results aim to guide land use planning and climate change mitigation considerations to reduce landslide risk.

Outcomes of radical prostatectomy in a 20-year localized prostate cancer single institution series in China

The long-term survival outcomes of radical prostatectomy(RP)in Chinese prostate cancer(PCa)patients are poorly understood.We conducted a single-center,retrospective analysis of patients undergoing RP to study the prognostic value of pathological and surgical information.From April 1998 to February 2022,782 patients undergoing RP at Queen Mary Hospital of The University of Hong Kong(Hong Kong,China)were included in our study.Multivariable Cox regression analysis and Kaplan–Meier analysis with stratification were performed.The 5-year,10-year,and 15-year overall survival(OS)rates were 96.6%,86.8%,and 70.6%,respectively,while the 5-year,10-year,and 15-year PCa-specific survival(PSS)rates were 99.7%,98.6%,and 97.8%,respectively.Surgical International Society of Urological Pathology PCa grades(ISUP Grade Group)≥4 was significantly associated with poorer PSS(hazard ratio[HR]=8.52,95%confidence interval[CI]:1.42–51.25,P=0.02).Pathological T3 stage was not significantly associated with PSS or OS in our cohort.Lymph node invasion and extracapsular extension might be associated with worse PSS(HR=20.30,95%CI:1.22–336.38,P=0.04;and HR=7.29,95%CI:1.22–43.64,P=0.03,respectively).Different surgical approaches(open,laparoscopic,or robotic-assisted)had similar outcomes in terms of PSS and OS.In conclusion,we report the longest timespan follow-up of Chinese PCa patients after RP with different approaches.

Germline mutations in 5’to c.7914 of BRCA2 significantly increase risk of prostate cancer

Dear Editor,Here,we report the association of mutations in the prostate cancer cluster region(PCCR;c.7914 to 3’)and non-PCCR(5’to c.7914)in breast cancer susceptibility gene 2(BRCA2)with prostate cancer(PCa)risk at the population level in Caucasian and Chinese cohorts.

W-boson mass anomaly from a general SU(2)_(L)scalar multiplet

We explain the W-boson mass anomaly by introducing an SU(2)_(L)scalar multiplet with general isospin and hypercharge{in the case without its vacuum expectation value}.It is shown that the dominant contribution from the scalar multiplet to the W-boson mass arises at the one-loop level,which can be expressed in terms of the electroweak(EW)oblique parameters T and S at leading order.We first rederive the general formulae of T and S induced by a scalar multiplet of EW charges,confirming the results in literature.We then study several specific examples of great phenomenological interest by applying these general expressions.As a result,it is found that the model with a scalar multiplet in an SU(2)_(L)real representation with Y=0 cannot generate the required M_(W)correction because it leads to vanishing values of T and S.However,the cases with scalars in a complex representation under SU(2)_(L)with a general hypercharge can explain the M_(W)excess observed by CDF-Ⅱowing to nonzero T and S.We further consider the strong constraints from the perturbativity and EW global fit of the precision data and vary the isospin representation and hypercharge of the additional scalar multiplet to assess the extent of the model to solve the W-boson mass anomaly.It turns out that these constraints play important roles in setting limits on the model parameter space.We also briefly describe the collider signatures of the extra scalar multiplet,especially when it contains long-lived,heavy,highly charged states.

三阴性乳腺癌的免疫治疗:机会与挑战

三阴性乳腺癌(triple negative breast,TNBC)是乳腺癌中预后最差、治疗难度最大、治疗方法最为欠缺的一个亚型.以免疫检查点抑制剂(immune checkpoint inhibitor,ICI)为主的免疫治疗革新了癌症治疗,同时也拓宽了TNBC患者的治疗选项.尽管如此,免疫治疗对于大多数TNBC患者疗效仍然有限.本文从肿瘤免疫环境的改变、ICI的疗效预测指标以及ICI与其它疗法联合应用克服对ICI耐药性等几个方面对TNBC患者的免疫治疗现状、所面临的问题以及未来发展方向进行了总结.希望能为ICI更有效地用于TNBC患者临床治疗提供一些有价值的参考.

Effects of yaw-roll coupling ratio on the lateral-directional departure prediction and restraint

The experimental data obtained from yaw-roll coupled wind tunnel tests are used for lateral-directional departure prediction,by linearizing the_b model to extract nominal dynamic derivatives at each coupling ratio.The prediction results are compared with those of the existing engineering methods which are based on the conventional aerodynamic derivatives.The comparison shows that the yaw-roll coupling ratio has a great influence on the departure susceptibility.The departure resistance will loss in partial region of the coupling ratio when the angle of attack is higher than a critical value.According to the stable and unstable regions of coupling ratio,a two-segment stability augmentation system with two different feedback gain matrices is obtained by pole-placement method.The two-segment stability augmentation system is used in the simulations of straight and level flight,steady turn,spin recovery and Herbst maneuver.The simulation results are also compared with the applications of a fixed-gain stability augmentation system designed by the conventional aerodynamic derivatives.When the yaw-roll coupling effects are fully considered,the two-segment stability augmentation system is more effective for departure restraint and can provide a better flying quality with less control energy.

Effects of yaw-roll coupling ratio on lateraldirectional aerodynamic characteristics

Experimental investigation of large amplitude yaw-roll coupled oscillations was conducted in a low-speed wind tunnel using an aircraft configuration model. A special test rig was designed and constructed to provide different coupled motions from low to high angles of attack.A parameter ‘‘coupling ratio" was introduced to indicate the extent of yaw-roll coupling. At each pitch angle, seven coupling ratios were designed to study the yaw-roll coupling effects on the lateraldirectional aerodynamic characteristics systematically. At high angles of attack, the damping characteristics of yawing and rolling moments drastically varied with coupling ratios. In the coupled motions with the rotation taking place about the wind axis, the lateral-directional aerodynamic moments exhibited unsteady characteristics and were different from the ‘‘quasi-steady" results of the rotary balance tests. The calculated results of the traditional aerodynamic derivative method were also compared with the experimental data. At low and very high angles of attack, the aerodynamic derivative method was applicative. However, within a wide range of angles of attack, the calculated results of aerodynamic derivative method were inconsistent with the experimental data, due to the drastic changes of damping characteristics of lateral-directional aerodynamic moments with yaw-roll coupling ratios.

Prostate Health Index(phi)and its derivatives predict Gleason score upgrading after radical prostatectomy among patients with low-risk prostate cancer

To analyze the performance of the Prostate Health Index(phi)and its derivatives for predicting Gleason score(GS)upgrading between prostate biopsy and radical prostatectomy(RP)in the Chinese population,an observational,prospective RP cohort consisting of 351 patients from two medical centers was established from January 2017 to September 2020.Pathological reclassification was determined by the Gleason Grade Group(GG).The area under the receiver operating characteristic curve(AUC)and logistic regression(LR)models were used to evaluate the predictive performance of predictors.In clinically low-risk patients with biopsy GG≤2,phi(odds ratio[OR]=1.80,95%confidence interval[95%CI]:1.14-2.82,P=0.01)and its derivative phi density(PHID;OR=2.34,95%CI:1.30-4.20,P=0.005)were significantly associated with upgrading to GG≥3 after RP,and the results were confirmed by multivariable analysis.Similar results were observed in patients with biopsy GG of 1 for the prediction of upgrading to RP GG≥2.Compared to the base model(AUC=0.59),addition of the phi or PHID could provide additional predictive value for GS upgrading in low-risk patients(AUC=0.69 and 0.71,respectively,both P<0.05).In conclusion,phi and PHID could predict GS upgrading after RP in clinically low-risk patients.

Time delay compensation in lateral-directional flight control systems at high angles of attack

The previous studies of time delay compensation in flight control systems are all based on the conventional aerodynamic derivative model and conducted in longitudinal motions at low angles of attack.In this investigation,the effects of time delay on the lateral-directional stability augmentation system in high-a regime are discussed based on theβmodel,which is proposed in our previous work and proved as a more accurate aerodynamic model to reveal the lateraldirectional unsteady aerodynamic characteristics at high angles of attack.Both theβmodel and the quasi-steady model are used for simulating the effects of time delay on the flying qualities in high-a maneuvers.The comparison between the simulation results shows that the flying qualities are much more sensitive to the mismatch of feedback gains than the state errors caused by time delay.Then a typical adaptive controller based on the conventional dynamic derivative model and a gain-prediction compensator based onβmodel are designed to address the time delay in different maneuvers.The simulation results show that the gain-prediction compensator is much simpler and more efficient at high angles of attack.Finally,the gain-prediction compensator is combined with a linearizedβmodel reference adaptive controller to compensate the adverse effects of very large time delay,which exhibits excellent performance when addressing the extreme conditions at high angles of attack.

Prostate volume does not provide additional predictive value to prostate health index for prostate cancer or clinically significant prostate cancer:results from a multicenter study in China

To evaluate whether prostate volume(PV)would provide additional predictive utility to the prostate health index(phi)for predicting prostate cancer(PCa)or clinically significant prostate cancer,we designed a prospective,observational multicenter study in two prostate biopsy cohorts.Cohort 1 included 595 patients from three medical centers from 2012 to 2013,and Cohort 2 included 1025 patients from four medical centers from 2013 to 2014.Area under the receiver operating characteristic curves(AUC)and logistic regression models were used to evaluate the predictive performance of PV-based derivatives and models.Linear regression analysis showed that both total prostate-specific antigen(tPSA)and free PSA(fPSA)were significantly correlated with PV(all P<0.05).[-2]proPSA(p2PSA)was significantly correlated with PV in Cohort 2(P<0.001)but not in Cohort 1(P=0.309),while no significant association was observed between phi and PV.When combining phi with PV,phi density(PHID)and another phi derivative(PHIV,calculated as phi/PV°5)did not outperform phi for predicting PCa or clinically significant PCa in either Cohort 1 or Cohort 2.Logistic regression analysis also showed that phi and PV were independent predictors for both PCa and clinically significant PCa(all P<0.05);however,PV did not provide additional predictive value to phi when combining these derivatives in a regression model(all models vs phi were not statistically significant,all P>0.05).In conclusion,PV-based derivatives(both PHIV and PHID)and models incorporating PV did not improve the predictive abilities of phi for either PCa or clinically significant PCa.

Krigings over space and time based on latent low-dimensional structures

We propose a new nonparametric approach to represent the linear dependence structure of a spatiotemporal process in terms of latent common factors.Though it is formally similar to the existing reduced rank approximation methods,the fundamental difference is that the low-dimensional structure is completely unknown in our setting,which is learned from the data collected irregularly over space but regularly in time.Furthermore,a graph Laplacian is incorporated in the learning in order to take the advantage of the continuity over space,and a new aggregation method via randomly partitioning space is introduced to improve the efficiency.We do not impose any stationarity conditions over space either,as the learning is facilitated by the stationarity in time.Krigings over space and time are carried out based on the learned low-dimensional structure,which is scalable to the cases when the data are taken over a large number of locations and/or over a long time period.Asymptotic properties of the proposed methods are established.An illustration with both simulated and real data sets is also reported.