Background: The prognostic values of staging parameters require continual re?assessment amid changes in diag?nostic and therapeutic methods. This study aimed to identify the prognostic factors and failure patterns of ...Background: The prognostic values of staging parameters require continual re?assessment amid changes in diag?nostic and therapeutic methods. This study aimed to identify the prognostic factors and failure patterns of non?meta?static nasopharyngeal carcinoma(NPC) in the intensity?modulated radiotherapy(IMRT) era.Methods: We reviewed the data from 749 patients with newly diagnosed, biopsy?proven, non?metastatic NPC in our cancer center(South China, an NPC endemic area) between January 2003 and December 2007. All patients under?went magnetic resonance imaging(MRI) before receiving IMRT. The actuarial survival rates were estimated using the Kaplan–Meier method, and survival curves were compared using the log?rank test. Multivariate analyses with the Cox proportional hazards model were used to test for the independent prognostic factors by backward eliminating insigniicant explanatory variables.Results: The 5?year occurrence rates of local failure, regional failure, locoregional failure, and distant failure were 5.4, 3.0, 7.4, and 17.4%, respectively. The 5?year survival rates were as follows: local relapse?free survival, 94.6%; nodal relapse?free survival, 97.0%; distant metastasis?free survival, 82.6%; disease?free survival, 75.1%; and overall survival, 82.0%. Multivariate Cox regression analysis revealed that orbit involvement was the only signiicant prognostic fac?tor for local failure(P = 0.011). Parapharyngeal tumor extension, retropharyngeal lymph node involvement, and the laterality, longest diameter, and Ho's location of the cervical lymph nodes were signiicant prognostic factors for both distant failure and disease failure(all P < 0.05). Intracranial extension had signiicant prognostic value for distant failure(P = 0.040).Conclusions: The key failure pattern for NPC was distant metastasis in the IMRT era. With changes in diagnostic and therapeutic technologies as well as treatment modalities, the signiicant prognostic parameters for local control have also been altered substantially.展开更多
The failure patterns and energy evolution of three types of shaft lining concrete subjected to static and dynamic loading were reported.The energy and damage characteristics of concrete were determined by means of a u...The failure patterns and energy evolution of three types of shaft lining concrete subjected to static and dynamic loading were reported.The energy and damage characteristics of concrete were determined by means of a uniaxial hydraulic servo machine,acoustic emission (AE) equipment,a split Hopkinson pressure bar (SHPB) and an ultrasonic wave analyser.The experimental results indicate that the confluence of multiple cracks forms a penetrating cross section in normal high-strength concrete (NHSC) under the condition of static loading,while the elastic energy that surges out at failure can cause tremendous damage when subjected to dynamic loading.A single crack was split into multiple propagation directions due to the presence of fibres in steel fibre-reinforced concrete (SFRC);adding fibre to concrete should be an effective way to dissipate energy.The non-steam-cured reactive powder concrete (NSC-RPC) designed in this paper can store and dissipate more energy than normal concrete,as NSC-RPC exhibits a strong ability to resist impact.Applying NSC-RPC to the long-service material of a shaft lining structure in deep underground engineering is quite effective.展开更多
The large-scale implementation of the Gully Stabilization and Land Reclamation(GSLR)project induces various failures of loess slopes due to excavation in Yan'an,China.However,the deformation and failure behavior o...The large-scale implementation of the Gully Stabilization and Land Reclamation(GSLR)project induces various failures of loess slopes due to excavation in Yan'an,China.However,the deformation and failure behavior of these excavated loess slopes have not been fully understood.In this study,field investigation was undertaken for analyzing the distributions and failure features of excavation-induced loess slope failures.It is found that plastic failure mainly occurs in Q_(3) loess layers and brittle failure in Q_(2).To understand the underlying failure mechanism,a series of triaxial shear tests were conducted on intact Q_(3) and Q_(2) loess samples that with different water contents,namely natural water content(natural),dry side of the natural value(drying 5%),and wet side(wetting 5%).The characteristics of stress-strain curves and failure modes of the samples were analyzed.Results show that the stress-strain curves of Q_(2) samples are dominated by strain-softening characteristics,while Q_(3) samples mainly exhibit strain-harden features except in the drying state.Correspondingly,shear failures of Q_(3) specimens are mainly caused by shear crack planes(single,X or V-shaped).For Q_(2) loess,the dominance of tensile cracks is observed on the surface of damaged specimens.These disclose the different failure modes of excavated slopes located in different strata,that is,the arc sliding failure of Q_(3) loess slopes and the stepped tensile failure of Q_(2) loess slopes,and are helpful in the design and management of the ongoing GSLR projects in the Loess Plateau.展开更多
PURPOSE:To review the efficacy and patterns of failure in average-risk medulloblastoma patients treated withconcurrent chemotherapy and reduced-dose cranial spinal irradiation and a conformal tumor bed boost.METH-ODS ...PURPOSE:To review the efficacy and patterns of failure in average-risk medulloblastoma patients treated withconcurrent chemotherapy and reduced-dose cranial spinal irradiation and a conformal tumor bed boost.METH-ODS AND MATERIALS:Thirty-three patients with average risk(defined as<==1.5 cm(2)of residual tumorafter resection,age>3 years,and no involvement of the cerebrospinal fluid or spine)medulloblastoma werediagnosed at our institution between January 1994 and December 2001.They were enrolled in an institutional展开更多
Background: Triple negative breast cancer (TNBC) tends to present aggressively with rapid progression and poor survival. Methods: We retrospectively reviewed patients’ files to define TNBC patients’ characteristics,...Background: Triple negative breast cancer (TNBC) tends to present aggressively with rapid progression and poor survival. Methods: We retrospectively reviewed patients’ files to define TNBC patients’ characteristics, predictive and prognostic factors, pattern of recurrence and survival. Results: 965 cases were identified. 147 patients (15.2%) were TNBC. 71.1% patients were premenopausal. T2, T3, T4 tumors represented 46.1%, 32% and 14.1%, respectively. N0, N1, N2, N3 disease represented 18.5%, 50.9%, 27.8% and 2.8%, respectively. Stages II, III & IV constituted 34.1%, 44.2% and 15.5%, respectively. 31.5% patients received neoadjuvant chemotherapy with 17.7% complete pathological response. 19.5%, 35.9%, 44.6% patients had unknown, ≤20 and >20 Ki67, respectively. Among non-metastatic patients (n = 108), 21.3% patients developed relapse with median time to relapse of 11 months. 78.3% of them had visceral (88.3% lung) metastasis, 13% bone metastasis, 21.7% brain metastasis and 13% LRR. There is significantly high risk of relapse in patients with large tumor size [T4: 66.75%, T3: 22.9%, T2: 16.7%, T1: 0% (p = 0.002)], positive LNs [N3: 100%, N2: 37.9%, N1: 15.1%, N0: 4.3% (p 0.001)] and Ki67 [>20: 31.6% versus 10.8% for Ki67 ≤ 20 (P = 0.007)]. Multivariate analysis revealed only T4 and N2-3 were significantly associated with high probability for relapse (P = 0.022 & 0.038). The 3-year DFS and OS were 73.2% and 75% respectively. For metastatic patients (n = 20), the m PFS was 7 months and m OS 1.5 years. Conclusion: Our data confirms the aggressive nature of TNBC with significant risk of relapse for patients with large tumor and positive lymph nodes. Maintenance metronomic capecitabine, neoadjuvant/adjuvant immunotherapy could be beneficial for non-metastatic patients. Lungs and brain were the most common sites of distant failure with poor survival that necessitates administration of molecular biomarkers (BRCA mutations, PD-L1 expression and microsatellite instability) for patients’ selection for novel targeted therapy.展开更多
Loess is long-term aeolian dust deposition, characterized by loose structure, concentrated participle distribution and unstable mineral composition, and thus easy to cause extensive collapsibility and have general wat...Loess is long-term aeolian dust deposition, characterized by loose structure, concentrated participle distribution and unstable mineral composition, and thus easy to cause extensive collapsibility and have general water sensitivity. To reveal the difference in water sensitivity between naturally intact(NI) loess and mechanically compacted(MC) loess used for the check dam, the transient water release and imbibition method(TRIM) was used to acquire the suction stress–expanded hydraulic characteristic curves for the NI and MC loess and explore possible approaches for formulating the potential of loess water sensitivity. Based on the Local Field of Safety(LFS) associated with slope stability, we constructed a finite element model of a check dam to depict its failure processes under different rainfall scenarios. The results revealed the strong water sensitivity in NI loess, while the MC loess retained a certain water-sensitive potential. This capacity depends on the ‘water sensitivity coefficient’ obtained from the suction-stress characteristic curve,which better presented the deformation potential of the two loess samples at different water content levels. In the context of LFS, we identified two failure patterns in the dam body that were involved in loess water sensitivity under hydromechanical conditions: rainfall erosion-induced shallow mudflow failure, and preferential-infiltration progressive failure. These patterns may provide new insights into dam-breakage mechanisms and potential chain effects of check dams on the Chinese Loess Plateau from the perspective of soil–water interactions, which is vital for predicting the position and timing of check dam failure, and mitigating risks.展开更多
<strong>Background:</strong><span><span><span style="font-family:""><span style="font-family:Verdana;"> In India approximately 20% of the patients with brea...<strong>Background:</strong><span><span><span style="font-family:""><span style="font-family:Verdana;"> In India approximately 20% of the patients with breast cancer are triple receptor negative. Owing to the aggressive nature and shorter disease-free survival judicious follow up and identification of failure pattern will benefit the patient. Similar studies have been conducted among non-Hispanic population and in China. This study aims to identify failure pattern in radically treated breast cancer patients who are triple receptor negative among Indian population. </span><b><span style="font-family:Verdana;">Methods</span></b><span style="font-family:Verdana;">: This prospective observational study was conducted in the Department of Radiation Oncology, a tertiary cancer centre in Kerala, India. The objective was to record the pattern of recurrence among triple negative breast cancer patients who completed their planned radical treatment. 171 patients with triple negative breast cancer were included in the study. Patients who completed the planned radical treatment were kept under regular follow up. Details of clinical examination and investigations during the follow up were recorded periodically. </span><b><span style="font-family:Verdana;">Results</span></b><span style="font-family:Verdana;">: Out of 171 patients 30 patients had </span></span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">a </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">recurrence of disease. Median age of the population was 53 years. Among the 30 patients who had </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">a </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">recurrence, 16 patients (53%) had systemic relapse and 14 patients (47%) had locoregional relapse. Lung was found to be the most common site of distant metastasis (37%). Ipsilateral chest wall was found to be the most common site of locoregional relapse (50%). 6 months disease free survival was found to be 91.8%</span></span></span><span><span><span style="font-family:""> </span></span></span><span><span><span style="font-family:""><span style="font-family:Verdana;">and 1-year disease free survival was found to be 70.2%. </span><b><span style="font-family:Verdana;">Conclusion</span></b><span style="font-family:Verdana;">: Among radically treated triple negative breast cancers relapses, systemic recurrence was more than locoregional recurrences.</span></span></span></span>展开更多
The mechanical characteristics and failure behavior of rocks containing flaws or discontinuities have received wide attention in the field of rock mechanics.When external loads are applied to rock materials,stress-ind...The mechanical characteristics and failure behavior of rocks containing flaws or discontinuities have received wide attention in the field of rock mechanics.When external loads are applied to rock materials,stress-induced cracks would initiate and propagate from the flaws,ultimately leading to the irreversible failure of rocks.To investigate the cracking behavior and the effect of flaw geometries on the mechanical properties of rock materials,a series of samples containing one,two and multiple flaws have been widely investigated in the laboratory.In this paper,the experimental results for pre-cracked rocks under quasistatic compression were systematically reviewed.The progressive failure process of intact rocks is briefly described to reveal the background for experiments on samples with flaws.Then,the nondestructive measurement techniques utilized in experiments,such as acoustic emission(AE),X-ray computed tomography(CT),and digital image correlation(DIC),are summarized.The mechanical characteristics of rocks with different flaw geometries and under different loading conditions,including the geometry of pre-existing flaws,flaw filling condition and confining pressure,are discussed.Furthermore,the cracking process is evaluated from the perspective of crack initiation,coalescence,and failure patterns.展开更多
Existing mechanism of simulating soil movement at tunnel face is generally based on the translational or rotational velocity field,which is,to some extent,different from the real soil movement in the arching zone.Nume...Existing mechanism of simulating soil movement at tunnel face is generally based on the translational or rotational velocity field,which is,to some extent,different from the real soil movement in the arching zone.Numerical simulations are carried out first to investigate the characteristics of the velocity distribution at tunnel face and above tunnel vault.Then a new kinematically admissible velocity field is proposed to improve the description of the soil movement according to the results of the numerical simulation.Based on the proposed velocity field,an improved failure mechanism is constructed adopting the spatial discretization technique,which takes into account soil arching effect and plastic deformation within soil mass.Finally,the critical face pressure and the proposed mechanism are compared with the results of the numerical simulation,existing analytical studies and experimental tests to verify the accuracy and improvement of the presented method.The proposed mechanism can serve as an alternative approach for the face stability analysis.展开更多
A clear understanding of the evolution characteristics of leaching solution’s damage to the basement rock of ion-adsorbed rare earth deposits is essential in the in situ leaching mining.In this study,some laboratory ...A clear understanding of the evolution characteristics of leaching solution’s damage to the basement rock of ion-adsorbed rare earth deposits is essential in the in situ leaching mining.In this study,some laboratory tests were carried out to investigate the deterioration behavior and failure mechanism of rock under the erosion of leaching solution.For this purpose,granite specimens were soaked in the leaching solution for different periods and then some physical and mechanical parameters were measured.The experimental results show that the strength of the rock without any soaking is the maximum.After 60 d,the rock strength,mass(dry)and P-wave velocity(dry)decrease to the minimum,while the porosity of the specimens reaches the maximum.Moreover,the failure pattern of the specimens in the uniaxial compression tests is affected as the soaking time increases.The scanning electron microscopy(SEM)image results indicate that the erosion of quartz crystals inside the rock specimens gets more intense with the increase of soaking time.Also,the internal crystal failure mode gradually changes from the trans-granular to the inter-granular.The insights gained from this study are helpful for better understanding the evolution characteristics of leaching solution’s damage to the basement rock of ionadsorbed rare earth deposits.展开更多
This paper proposes a numerical three-dimensional(3D)mesoscopic approach based on the discrete element method combined with X-ray computed tomography(XCT)images to characterize the dynamic impact behavior of heterogen...This paper proposes a numerical three-dimensional(3D)mesoscopic approach based on the discrete element method combined with X-ray computed tomography(XCT)images to characterize the dynamic impact behavior of heterogeneous coal-rock(HCR).The dynamic impact loading in three directions was modelled to investigate the effects of the 3D meso-structure on the failure patterns and fracture mechanism,with different impact velocities.The XCT image-based discrete element model of HCR was calibrated through appropriate standard uniaxial compression tests.Numerical simulations were carried out to investigate how the breakage behaviors are affected by different loading directions with different impact velocities.The loading direction,input energy,and spatial distribution of the mineral phase had a remarkable influence on the failure patterns and load-carrying capacities.The shape of the gangue phase and the approximate location of the gangue interfaces are key parameters to consider when investigating the failure patterns and fracture mechanism of heterogeneous rock materials.The damage and fracture tended to propagate from the surfaces to the HCR interior.The gangue phase area contacting the loading wall,growth direction of the strong gangue interfaces,and loading directions greatly influenced the failure patterns of the heterogeneous rock materials.展开更多
The existence of defects in a rock mass is a vital factor complicating the mechanical response of the rock mass under stress.The characteristics of defects control the rock mass’s mechanical behaviors.This report rev...The existence of defects in a rock mass is a vital factor complicating the mechanical response of the rock mass under stress.The characteristics of defects control the rock mass’s mechanical behaviors.This report reviews the experimental studies on the influence of simulating the internal defects of rock mass’s mechanical properties.The effects of preexisting defects(shape,size,number,angle,and other factors)on the mechanical properties and failure modes of the rock are investigated from the perspectives of rock failure and fracture mechanics.The fracture propagation mechanisms of different defective rock masses are analyzed by studying the stress state of different defective rock masses under uniaxial compression.After the defective rock samples with varying inclination angles are destroyed,the relationship among the compressive strength,the fracture propagation,and the failure characteristics is explored.The primary findings are as follows.The increase in the size and number of defects rapidly damages the mechanical properties of the rock and intensifies defect penetration and expansion.The rock mechanics characteristics of fissured rocks with different inclination angles show two primary variations:one is a continuous increase,and the other is a decrease followed by an increase.This result is strongly related to the failure pattern of rocks with preexisting fissures.This investigation is crucial for further studying the failure modes of complex defective rock masses and the geotechnical engineering related to defective rocks.展开更多
In this study,the strain rate-dependent dynamic tensile behavior of ZrB2-20%SiC ceramic composite was investigated using experimental and numerical approaches.The split Hopkinson pressure bar apparatus was used to mea...In this study,the strain rate-dependent dynamic tensile behavior of ZrB2-20%SiC ceramic composite was investigated using experimental and numerical approaches.The split Hopkinson pressure bar apparatus was used to measure the dynamic splitting tensile response at strain rates of 17-67 s^(−1).The experiment results demonstrate a significant strain rate dependence of the dynamic tensile behavior of the ZrB2-SiC ceramic composite.The dynamic tensile strength increased linearly with the strain rate,from 288 MPa at 17 s^(−1)to 654 MPa at 67 s^(−1).Moreover,a strain rate-dependent tensile strength was introduced into a modified JH-2 model to describe the dynamic tensile behavior and fracture process of ZrB2-SiC ceramics.The numerical results of dynamic tensile strength agree well with the experimental result.Moreover,the fracture process of ZrB2-SiC ceramics under dynamic tension was further studied by combining high-speed images and numerical results.The effect of strain rate on the fracture process and failure patterns of the ZrB2-SiC ceramic composite could be verified by the modified JH-2 model.展开更多
The waterproofing capacity of segmental joints is an essential indicator for the long-term service performance of shield tunnels.The segmental joints with double gaskets have been adopted to improve the waterproof per...The waterproofing capacity of segmental joints is an essential indicator for the long-term service performance of shield tunnels.The segmental joints with double gaskets have been adopted to improve the waterproof performance for certain tunnels with high water pressure,especially water-conveyance tunnels.This paper presents a series of waterproofing tests on joints with different settings of double gaskets via an improved test apparatus.Four cases are investigated,including(i)double gaskets with equal high/low waterproof capacity,(ii)the outer gasket with higher waterproof capacity,and(iii)the outer gasket with lower waterproof capacity.Different joint openings are also considered.Moreover,the water pressures at two cavities are continuously monitored to highlight the waterproofing mechanism and failure pattern of double gaskets.The results demonstrate that the gasket with the higher waterproofing capacity dominates the overall waterproofing capacity of joint with double gaskets;only a little enhancement of the waterproofing capacity is found for the joint with the same double gaskets.The waterproofing capacity of joints with double gaskets decreases with the increase of the joint opening.The failure pattern depends on the arrangement of double gaskets,and four stages can be identified during the whole failure process.The advantages of double gaskets in case of joint rotation are also discussed.展开更多
基金supported by grants from the Key Laboratory Construction Project of Guangzhou City,China (121800085)the Health & Medical Collaborative Innovation Project of Guangzhou City,China (201400000001)+2 种基金the National Science & Technology Pillar Program during the Twelfth Five-year Plan Period (2014BAI09B10)the National Natural Science Foundation of China (81201746)the Planned Science and Technology Project of Guangdong Province,China (2013B020400004)
文摘Background: The prognostic values of staging parameters require continual re?assessment amid changes in diag?nostic and therapeutic methods. This study aimed to identify the prognostic factors and failure patterns of non?meta?static nasopharyngeal carcinoma(NPC) in the intensity?modulated radiotherapy(IMRT) era.Methods: We reviewed the data from 749 patients with newly diagnosed, biopsy?proven, non?metastatic NPC in our cancer center(South China, an NPC endemic area) between January 2003 and December 2007. All patients under?went magnetic resonance imaging(MRI) before receiving IMRT. The actuarial survival rates were estimated using the Kaplan–Meier method, and survival curves were compared using the log?rank test. Multivariate analyses with the Cox proportional hazards model were used to test for the independent prognostic factors by backward eliminating insigniicant explanatory variables.Results: The 5?year occurrence rates of local failure, regional failure, locoregional failure, and distant failure were 5.4, 3.0, 7.4, and 17.4%, respectively. The 5?year survival rates were as follows: local relapse?free survival, 94.6%; nodal relapse?free survival, 97.0%; distant metastasis?free survival, 82.6%; disease?free survival, 75.1%; and overall survival, 82.0%. Multivariate Cox regression analysis revealed that orbit involvement was the only signiicant prognostic fac?tor for local failure(P = 0.011). Parapharyngeal tumor extension, retropharyngeal lymph node involvement, and the laterality, longest diameter, and Ho's location of the cervical lymph nodes were signiicant prognostic factors for both distant failure and disease failure(all P < 0.05). Intracranial extension had signiicant prognostic value for distant failure(P = 0.040).Conclusions: The key failure pattern for NPC was distant metastasis in the IMRT era. With changes in diagnostic and therapeutic technologies as well as treatment modalities, the signiicant prognostic parameters for local control have also been altered substantially.
基金the National Natural Science Foundation of China(No.51678049)the State Key Research Development Program of China(No.2016YFC0600803)。
文摘The failure patterns and energy evolution of three types of shaft lining concrete subjected to static and dynamic loading were reported.The energy and damage characteristics of concrete were determined by means of a uniaxial hydraulic servo machine,acoustic emission (AE) equipment,a split Hopkinson pressure bar (SHPB) and an ultrasonic wave analyser.The experimental results indicate that the confluence of multiple cracks forms a penetrating cross section in normal high-strength concrete (NHSC) under the condition of static loading,while the elastic energy that surges out at failure can cause tremendous damage when subjected to dynamic loading.A single crack was split into multiple propagation directions due to the presence of fibres in steel fibre-reinforced concrete (SFRC);adding fibre to concrete should be an effective way to dissipate energy.The non-steam-cured reactive powder concrete (NSC-RPC) designed in this paper can store and dissipate more energy than normal concrete,as NSC-RPC exhibits a strong ability to resist impact.Applying NSC-RPC to the long-service material of a shaft lining structure in deep underground engineering is quite effective.
基金funded by the Natural Science Foundation of China(Nos.41790442 and 41825018)the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDA23090402)the State Key Research Development Program of China(No.2017YFD0800501)。
文摘The large-scale implementation of the Gully Stabilization and Land Reclamation(GSLR)project induces various failures of loess slopes due to excavation in Yan'an,China.However,the deformation and failure behavior of these excavated loess slopes have not been fully understood.In this study,field investigation was undertaken for analyzing the distributions and failure features of excavation-induced loess slope failures.It is found that plastic failure mainly occurs in Q_(3) loess layers and brittle failure in Q_(2).To understand the underlying failure mechanism,a series of triaxial shear tests were conducted on intact Q_(3) and Q_(2) loess samples that with different water contents,namely natural water content(natural),dry side of the natural value(drying 5%),and wet side(wetting 5%).The characteristics of stress-strain curves and failure modes of the samples were analyzed.Results show that the stress-strain curves of Q_(2) samples are dominated by strain-softening characteristics,while Q_(3) samples mainly exhibit strain-harden features except in the drying state.Correspondingly,shear failures of Q_(3) specimens are mainly caused by shear crack planes(single,X or V-shaped).For Q_(2) loess,the dominance of tensile cracks is observed on the surface of damaged specimens.These disclose the different failure modes of excavated slopes located in different strata,that is,the arc sliding failure of Q_(3) loess slopes and the stepped tensile failure of Q_(2) loess slopes,and are helpful in the design and management of the ongoing GSLR projects in the Loess Plateau.
文摘PURPOSE:To review the efficacy and patterns of failure in average-risk medulloblastoma patients treated withconcurrent chemotherapy and reduced-dose cranial spinal irradiation and a conformal tumor bed boost.METH-ODS AND MATERIALS:Thirty-three patients with average risk(defined as<==1.5 cm(2)of residual tumorafter resection,age>3 years,and no involvement of the cerebrospinal fluid or spine)medulloblastoma werediagnosed at our institution between January 1994 and December 2001.They were enrolled in an institutional
文摘Background: Triple negative breast cancer (TNBC) tends to present aggressively with rapid progression and poor survival. Methods: We retrospectively reviewed patients’ files to define TNBC patients’ characteristics, predictive and prognostic factors, pattern of recurrence and survival. Results: 965 cases were identified. 147 patients (15.2%) were TNBC. 71.1% patients were premenopausal. T2, T3, T4 tumors represented 46.1%, 32% and 14.1%, respectively. N0, N1, N2, N3 disease represented 18.5%, 50.9%, 27.8% and 2.8%, respectively. Stages II, III & IV constituted 34.1%, 44.2% and 15.5%, respectively. 31.5% patients received neoadjuvant chemotherapy with 17.7% complete pathological response. 19.5%, 35.9%, 44.6% patients had unknown, ≤20 and >20 Ki67, respectively. Among non-metastatic patients (n = 108), 21.3% patients developed relapse with median time to relapse of 11 months. 78.3% of them had visceral (88.3% lung) metastasis, 13% bone metastasis, 21.7% brain metastasis and 13% LRR. There is significantly high risk of relapse in patients with large tumor size [T4: 66.75%, T3: 22.9%, T2: 16.7%, T1: 0% (p = 0.002)], positive LNs [N3: 100%, N2: 37.9%, N1: 15.1%, N0: 4.3% (p 0.001)] and Ki67 [>20: 31.6% versus 10.8% for Ki67 ≤ 20 (P = 0.007)]. Multivariate analysis revealed only T4 and N2-3 were significantly associated with high probability for relapse (P = 0.022 & 0.038). The 3-year DFS and OS were 73.2% and 75% respectively. For metastatic patients (n = 20), the m PFS was 7 months and m OS 1.5 years. Conclusion: Our data confirms the aggressive nature of TNBC with significant risk of relapse for patients with large tumor and positive lymph nodes. Maintenance metronomic capecitabine, neoadjuvant/adjuvant immunotherapy could be beneficial for non-metastatic patients. Lungs and brain were the most common sites of distant failure with poor survival that necessitates administration of molecular biomarkers (BRCA mutations, PD-L1 expression and microsatellite instability) for patients’ selection for novel targeted therapy.
基金financially supported by the National Natural Science Foundation of China(Grant Nos.41530640 and 41731289)the National Key Research and Development Program of China(Grant No.2018YFC1504701)。
文摘Loess is long-term aeolian dust deposition, characterized by loose structure, concentrated participle distribution and unstable mineral composition, and thus easy to cause extensive collapsibility and have general water sensitivity. To reveal the difference in water sensitivity between naturally intact(NI) loess and mechanically compacted(MC) loess used for the check dam, the transient water release and imbibition method(TRIM) was used to acquire the suction stress–expanded hydraulic characteristic curves for the NI and MC loess and explore possible approaches for formulating the potential of loess water sensitivity. Based on the Local Field of Safety(LFS) associated with slope stability, we constructed a finite element model of a check dam to depict its failure processes under different rainfall scenarios. The results revealed the strong water sensitivity in NI loess, while the MC loess retained a certain water-sensitive potential. This capacity depends on the ‘water sensitivity coefficient’ obtained from the suction-stress characteristic curve,which better presented the deformation potential of the two loess samples at different water content levels. In the context of LFS, we identified two failure patterns in the dam body that were involved in loess water sensitivity under hydromechanical conditions: rainfall erosion-induced shallow mudflow failure, and preferential-infiltration progressive failure. These patterns may provide new insights into dam-breakage mechanisms and potential chain effects of check dams on the Chinese Loess Plateau from the perspective of soil–water interactions, which is vital for predicting the position and timing of check dam failure, and mitigating risks.
文摘<strong>Background:</strong><span><span><span style="font-family:""><span style="font-family:Verdana;"> In India approximately 20% of the patients with breast cancer are triple receptor negative. Owing to the aggressive nature and shorter disease-free survival judicious follow up and identification of failure pattern will benefit the patient. Similar studies have been conducted among non-Hispanic population and in China. This study aims to identify failure pattern in radically treated breast cancer patients who are triple receptor negative among Indian population. </span><b><span style="font-family:Verdana;">Methods</span></b><span style="font-family:Verdana;">: This prospective observational study was conducted in the Department of Radiation Oncology, a tertiary cancer centre in Kerala, India. The objective was to record the pattern of recurrence among triple negative breast cancer patients who completed their planned radical treatment. 171 patients with triple negative breast cancer were included in the study. Patients who completed the planned radical treatment were kept under regular follow up. Details of clinical examination and investigations during the follow up were recorded periodically. </span><b><span style="font-family:Verdana;">Results</span></b><span style="font-family:Verdana;">: Out of 171 patients 30 patients had </span></span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">a </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">recurrence of disease. Median age of the population was 53 years. Among the 30 patients who had </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">a </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">recurrence, 16 patients (53%) had systemic relapse and 14 patients (47%) had locoregional relapse. Lung was found to be the most common site of distant metastasis (37%). Ipsilateral chest wall was found to be the most common site of locoregional relapse (50%). 6 months disease free survival was found to be 91.8%</span></span></span><span><span><span style="font-family:""> </span></span></span><span><span><span style="font-family:""><span style="font-family:Verdana;">and 1-year disease free survival was found to be 70.2%. </span><b><span style="font-family:Verdana;">Conclusion</span></b><span style="font-family:Verdana;">: Among radically treated triple negative breast cancers relapses, systemic recurrence was more than locoregional recurrences.</span></span></span></span>
基金financial support from the National Key R&D Program of China(Grant No.2020YFA0711802)。
文摘The mechanical characteristics and failure behavior of rocks containing flaws or discontinuities have received wide attention in the field of rock mechanics.When external loads are applied to rock materials,stress-induced cracks would initiate and propagate from the flaws,ultimately leading to the irreversible failure of rocks.To investigate the cracking behavior and the effect of flaw geometries on the mechanical properties of rock materials,a series of samples containing one,two and multiple flaws have been widely investigated in the laboratory.In this paper,the experimental results for pre-cracked rocks under quasistatic compression were systematically reviewed.The progressive failure process of intact rocks is briefly described to reveal the background for experiments on samples with flaws.Then,the nondestructive measurement techniques utilized in experiments,such as acoustic emission(AE),X-ray computed tomography(CT),and digital image correlation(DIC),are summarized.The mechanical characteristics of rocks with different flaw geometries and under different loading conditions,including the geometry of pre-existing flaws,flaw filling condition and confining pressure,are discussed.Furthermore,the cracking process is evaluated from the perspective of crack initiation,coalescence,and failure patterns.
基金financial support provided by the National Natural Science Foundation of China(Grant No.51978042)。
文摘Existing mechanism of simulating soil movement at tunnel face is generally based on the translational or rotational velocity field,which is,to some extent,different from the real soil movement in the arching zone.Numerical simulations are carried out first to investigate the characteristics of the velocity distribution at tunnel face and above tunnel vault.Then a new kinematically admissible velocity field is proposed to improve the description of the soil movement according to the results of the numerical simulation.Based on the proposed velocity field,an improved failure mechanism is constructed adopting the spatial discretization technique,which takes into account soil arching effect and plastic deformation within soil mass.Finally,the critical face pressure and the proposed mechanism are compared with the results of the numerical simulation,existing analytical studies and experimental tests to verify the accuracy and improvement of the presented method.The proposed mechanism can serve as an alternative approach for the face stability analysis.
基金funded by the National Natural Science Foundation of China (Grant No. 51764014)the Natural Science Foundation of Jiangxi Province of China (Grant No. 20192BAB206018)+2 种基金the Education Commission of Jiangxi Province of China (GJJ160674)the Youth Jinggang Scholars Program in Jiangxi Provincethe Innovative Leading Talents Program in Ganzhou and Chongyi Zhangyuan Tungsten Co. Ltd., China, for the kind supports
文摘A clear understanding of the evolution characteristics of leaching solution’s damage to the basement rock of ion-adsorbed rare earth deposits is essential in the in situ leaching mining.In this study,some laboratory tests were carried out to investigate the deterioration behavior and failure mechanism of rock under the erosion of leaching solution.For this purpose,granite specimens were soaked in the leaching solution for different periods and then some physical and mechanical parameters were measured.The experimental results show that the strength of the rock without any soaking is the maximum.After 60 d,the rock strength,mass(dry)and P-wave velocity(dry)decrease to the minimum,while the porosity of the specimens reaches the maximum.Moreover,the failure pattern of the specimens in the uniaxial compression tests is affected as the soaking time increases.The scanning electron microscopy(SEM)image results indicate that the erosion of quartz crystals inside the rock specimens gets more intense with the increase of soaking time.Also,the internal crystal failure mode gradually changes from the trans-granular to the inter-granular.The insights gained from this study are helpful for better understanding the evolution characteristics of leaching solution’s damage to the basement rock of ionadsorbed rare earth deposits.
基金The authors gratefully acknowledge the financial support received from the China Postdoctoral Science Foundation(2018M630676)National Nature Science Foundation of China(Nos.51675521 and 51779224)+1 种基金Zhejiang Basic Public Welfare Research Program(No.LHZ19E090002)and Open Founda-tion of Shandong Province Key Laboratory of Mine Mechanical.Engineering(No.2019KLMM105).
文摘This paper proposes a numerical three-dimensional(3D)mesoscopic approach based on the discrete element method combined with X-ray computed tomography(XCT)images to characterize the dynamic impact behavior of heterogeneous coal-rock(HCR).The dynamic impact loading in three directions was modelled to investigate the effects of the 3D meso-structure on the failure patterns and fracture mechanism,with different impact velocities.The XCT image-based discrete element model of HCR was calibrated through appropriate standard uniaxial compression tests.Numerical simulations were carried out to investigate how the breakage behaviors are affected by different loading directions with different impact velocities.The loading direction,input energy,and spatial distribution of the mineral phase had a remarkable influence on the failure patterns and load-carrying capacities.The shape of the gangue phase and the approximate location of the gangue interfaces are key parameters to consider when investigating the failure patterns and fracture mechanism of heterogeneous rock materials.The damage and fracture tended to propagate from the surfaces to the HCR interior.The gangue phase area contacting the loading wall,growth direction of the strong gangue interfaces,and loading directions greatly influenced the failure patterns of the heterogeneous rock materials.
基金supported by the National Key Research and Development Program of China,(Grant No.2019YFC1509702).
文摘The existence of defects in a rock mass is a vital factor complicating the mechanical response of the rock mass under stress.The characteristics of defects control the rock mass’s mechanical behaviors.This report reviews the experimental studies on the influence of simulating the internal defects of rock mass’s mechanical properties.The effects of preexisting defects(shape,size,number,angle,and other factors)on the mechanical properties and failure modes of the rock are investigated from the perspectives of rock failure and fracture mechanics.The fracture propagation mechanisms of different defective rock masses are analyzed by studying the stress state of different defective rock masses under uniaxial compression.After the defective rock samples with varying inclination angles are destroyed,the relationship among the compressive strength,the fracture propagation,and the failure characteristics is explored.The primary findings are as follows.The increase in the size and number of defects rapidly damages the mechanical properties of the rock and intensifies defect penetration and expansion.The rock mechanics characteristics of fissured rocks with different inclination angles show two primary variations:one is a continuous increase,and the other is a decrease followed by an increase.This result is strongly related to the failure pattern of rocks with preexisting fissures.This investigation is crucial for further studying the failure modes of complex defective rock masses and the geotechnical engineering related to defective rocks.
基金This work was supported by the National Natural Science Foundation of China(Grant Nos.11602061 and 51968009)Science and Technology Planning Project of Guizhou Province(Grant Nos.[2017]1033 and[2020]1Y244)Civil Engineering First-Class Discipline Construction Project of Guizhou Province(Grant No.QYNYL[2017]0013).
文摘In this study,the strain rate-dependent dynamic tensile behavior of ZrB2-20%SiC ceramic composite was investigated using experimental and numerical approaches.The split Hopkinson pressure bar apparatus was used to measure the dynamic splitting tensile response at strain rates of 17-67 s^(−1).The experiment results demonstrate a significant strain rate dependence of the dynamic tensile behavior of the ZrB2-SiC ceramic composite.The dynamic tensile strength increased linearly with the strain rate,from 288 MPa at 17 s^(−1)to 654 MPa at 67 s^(−1).Moreover,a strain rate-dependent tensile strength was introduced into a modified JH-2 model to describe the dynamic tensile behavior and fracture process of ZrB2-SiC ceramics.The numerical results of dynamic tensile strength agree well with the experimental result.Moreover,the fracture process of ZrB2-SiC ceramics under dynamic tension was further studied by combining high-speed images and numerical results.The effect of strain rate on the fracture process and failure patterns of the ZrB2-SiC ceramic composite could be verified by the modified JH-2 model.
基金financially supported by National Natural Science Foundation of China(52090083)Shanghai Committee of Science and Technology(20DZ1202600)China Railway Southern Investment Group Co.Ltd(Project No.ZTNF-2020-1).
文摘The waterproofing capacity of segmental joints is an essential indicator for the long-term service performance of shield tunnels.The segmental joints with double gaskets have been adopted to improve the waterproof performance for certain tunnels with high water pressure,especially water-conveyance tunnels.This paper presents a series of waterproofing tests on joints with different settings of double gaskets via an improved test apparatus.Four cases are investigated,including(i)double gaskets with equal high/low waterproof capacity,(ii)the outer gasket with higher waterproof capacity,and(iii)the outer gasket with lower waterproof capacity.Different joint openings are also considered.Moreover,the water pressures at two cavities are continuously monitored to highlight the waterproofing mechanism and failure pattern of double gaskets.The results demonstrate that the gasket with the higher waterproofing capacity dominates the overall waterproofing capacity of joint with double gaskets;only a little enhancement of the waterproofing capacity is found for the joint with the same double gaskets.The waterproofing capacity of joints with double gaskets decreases with the increase of the joint opening.The failure pattern depends on the arrangement of double gaskets,and four stages can be identified during the whole failure process.The advantages of double gaskets in case of joint rotation are also discussed.
