Objective We studied the efficacy of salvage hepatectomy for treating recurrent hepatic cancer after radiofrequency ablation(RFA). Methods A retrospective analysis of 67 patients who had recurrent liver cancer after R...Objective We studied the efficacy of salvage hepatectomy for treating recurrent hepatic cancer after radiofrequency ablation(RFA). Methods A retrospective analysis of 67 patients who had recurrent liver cancer after RFA treatment and received salvage hepatectomy in the Department of Hepatobiliary Surgery, Southwest Hospital, Third Military Medical University(China), from January 2006 to January 2014, was performed. The analysis included patient gender, age, hepatitis type, alpha-fetoprotein(AFP), and TNM stage prior to RFA and salvage hepatectomy, overall survival rates, and tumor-free survival rates after salvage hepatectomy. Results Among the 67 patients, there were 57 cases of hepatitis B, two cases of hepatitis C, and eight cases did not have hepatitis. AFP levels in patients ranged from 3 to 4521 ng/m L(median 33 ng/m L). Before RFA, 54 cases were stage I tumors, and 13 were stage II tumors. Tumor sizes varied from 0.82 to 4.83 cm(median 3.0 cm). In 20 cases, one RFA was performed, and for 47 cases, RFA was repeated. RFAablated region diameters ranged from 3.8 to 5.2 cm(median 4.5 cm). The interval between the salvage surgical resection and RFA was 3–37 months. Before salvage hepatectomy, 23 stage I tumors, 12 stage II tumors, and 32 stage III tumors were present(size ranged 4.83–11.84 cm; median 6.3 cm). For salvage hepatectomy, laparotomy was performed for 56 cases, and laparoscopy was performed for 28 cases. Inflow clamping was performed for 39 cases(15–45 min). Surgery was 219–370 min and intraoperative blood loss was 100–2100 m L. For 13 cases, intraoperative blood transfusion was required. Tumor pathological data revealed 31, 35, and 1 poorly, moderately, and well differentiated tumors, respectively. No patients died due to operative complications, and hospital stays were 8–10 days. Overall and tumor-free survival rates were 85% and 79% for 1 year, 50% and 20% for 3 years, and 39% and 19% for 5 years, respectively. KaplanMeier analysis and Cox regression confirmed that tumor number and size prior to salvage liver cancer were risk factors affecting survival. Conclusion Patients who received RFA to treat early-stage liver cancer with postoperative recurrent stage I tumors have satisfactory outcomes with salvage hepatectomy.展开更多
As an essential renewable mineral resource,mollusk shells can be used as handicrafts,building materials,adsor-bents,etc.However,there are few reports on the wear resistance of their structures.The Vicker’s hardness a...As an essential renewable mineral resource,mollusk shells can be used as handicrafts,building materials,adsor-bents,etc.However,there are few reports on the wear resistance of their structures.The Vicker’s hardness and friction,and wear resistance of different microstructures in mollusk shells were comparatively studied in the pre-sent work.The hardness of prismatic structures is lower than that of cross-lamellar and nacreous structures.How-ever,the experimental results of sliding tests indicate that the prismatic structure exhibits the best anti-wear ability compared with foliated,crossed-lamellar,and nacreous structures.The anti-wear and hardness do not present a positive correlation,as the wear resistance properties of different microstructures in mollusk shells are governed jointly by organic matrix,structural arrangement,and basic building block actions.The present researchfindings are expected to provide fundamental insight into the design of renewable bionic materials with high wear resistance.展开更多
In this paper, we present the analytical expressions for computing the minimum distance between a point and a torus, which is called the orthogonal projection point problem. If the test point is on the outside of the ...In this paper, we present the analytical expressions for computing the minimum distance between a point and a torus, which is called the orthogonal projection point problem. If the test point is on the outside of the torus and the test point is at the center axis of the torus, we present that the orthogonal projection point set is a circle perpendicular to the center axis of the torus;if not, the analytical expression for the orthogonal projection point problem is also given. Furthermore, if the test point is in the inside of the torus, we also give the corresponding analytical expression for orthogonal projection point for two cases.展开更多
A high specific Young’s modulus steel could be achieved by introducing a large fraction of kappa-carbides(κ-carbide),and its ductility was improved by efficiency divorced eutectoid transformation(DET)treatment.For t...A high specific Young’s modulus steel could be achieved by introducing a large fraction of kappa-carbides(κ-carbide),and its ductility was improved by efficiency divorced eutectoid transformation(DET)treatment.For this steel,carbon and aluminum contents affect not only the carbide fraction,but also the type and morphology of carbides,and consequently the mechanical properties.In this work,the alloy was designed by considering both the carbide morphology and Young’s modulus,and the carbides in the high specific Young’s modulus steels were adjusted by controlling carbon content in a suitable range for achieving a good combination of strength and ductility.The detailed microstructure evolution process during DET reaction was studied,and it was found that a higher austenitizing temperature and the cooling rate lower than 300℃ h^(−1) are suitable.The blocky carbides could be avoided by designing the carbon content in a limited content range.The microstructure-property relationship of the experimental steels was also discussed for giving an impetus to the future development of high specific Young’s modulus steels.展开更多
Grain boundary engineering(GBE) is a practice of improving resistance to grain boundary failure of the material through increasing the proportion of low Σ coincidence site lattice(CSL) grain boundaries(special g...Grain boundary engineering(GBE) is a practice of improving resistance to grain boundary failure of the material through increasing the proportion of low Σ coincidence site lattice(CSL) grain boundaries(special grain boundaries) in the grain boundary character distribution(GBCD). The GBCD in a cold rolled and annealed Fe-18Cr-18Mn-0.63N high-nitrogen austenitic stainless steel was analyzed by electron back scatter difraction(EBSD). The results show that the optimization process of GBE in the conventional austenitic stainless steel cannot be well applied to this high-nitrogen austenitic stainless steel. The percentage of low ΣCSL grain boundaries could increase from 47.3% for the solid solution treated high-nitrogen austenitic stainless steel specimen to 82.0% for the specimen after 5% cold rolling reduction and then annealing at 1423 K for 10 min.These special boundaries of high proportion efectively interrupt the connectivity of conventional high angle grain boundary network and thus achieve the GBCD optimization for the high-nitrogen austenitic stainless steel.展开更多
Employing the intermediate derivatization method(IDM), twenty novel 1,3,4-oxadiazole derivatives containing arylpyrazoloxyl moiety were designed and synthesized. The structures of the title compounds were identified...Employing the intermediate derivatization method(IDM), twenty novel 1,3,4-oxadiazole derivatives containing arylpyrazoloxyl moiety were designed and synthesized. The structures of the title compounds were identified by1 H NMR,13 C NMR, MS and elemental analyses, compound 4 was further identified by single-crystal X-ray diffraction. Antifungal activities against rice sheath blight(RSB) and sorghum anthracnose(SA) were evaluated by the mycelium linear growth rate method. Compounds 4, 16 and 20 displayed significant activities against RSB(EC50= 0.88 mg/L, 0.91 mg/L and 0.85 mg/L, respectively),higher than the reference tebuconazole; While compound 3 exhibited higher activity against SA(EC50= 1.03 mg/L), equal to commercial pyraclostrobin(EC50= 1.06 mg/L). The study showed that compound 20 is a promising fungicide for further development.展开更多
Dear Editor,Tailed,double-stranded DNA(dsDNA)bacteriophages,which belong to the order of Caudovirales,have a tail attached to a pentameric vertex of the icosahedral capsid shell(head)through a 12-fold portal(Johnson a...Dear Editor,Tailed,double-stranded DNA(dsDNA)bacteriophages,which belong to the order of Caudovirales,have a tail attached to a pentameric vertex of the icosahedral capsid shell(head)through a 12-fold portal(Johnson and Chiu,2007).The phages package genomic dsDNA into a round procapsid using the portal in complex with an ATP-dependent terminase complex as the motor.During packaging,the procapsid shell expands to a more angular intermediate to match the size of the viral genome(Guo et al.,2014).When the phage head is full,the portal detects internal pressure and conveys a signal from the inner capsid to the exterior,which triggers a sequence of events-the terminase complex cleaving mature DNA genome from a multi-genome concatemer,the release of the terminase complex from the portal,and the attachment of the tail complex-in the completion of phage assembly(Lander et al.,2006;Johnson and Chiu,2007).At the beginning of phage infection,the tail is responsible for receptor recognition,and the portal and tail act as a tunnel for DNA delivery into the host cytoplasm(Johnson and Chiu,2007).These mechanisms of DNA packaging and ejection may also be conserved in many other DNA viruses,including herpesvirus(Wang et al.,2020;Yang et al.,2020).展开更多
In this paper, we investigate how to compute the minimum distance between a point and a parametric surface, and then to return the nearest point (foot point) on the surface as well as its corresponding parameter, whic...In this paper, we investigate how to compute the minimum distance between a point and a parametric surface, and then to return the nearest point (foot point) on the surface as well as its corresponding parameter, which is also called the point projection problem of a parametric surface. The geometric strategy algorithm (hereafter GSA) presented consists of two parts as follows. The normal curvature to a given parametric surface is used to find the corresponding foot point firstly, and then the Taylor's expansion of the parametric surface is employed to compute parameter increments and to get the iteration formula to calculate the orthogonal projection point of test point to the parametric surface. Our geometric strategy algorithm is essentially dependent on the geometric property of the normal curvature, and performs better than existing methods in two ways. Firstly, GSA converges faster than existing methods, such as the method to turn the problem into a root-finding of nonlinear system, subdividing methods, clipping methods, geometric methods (tangent vector and geometric curvature) and hybrid second-order method, etc. Specially, it converges faster than the classical Newton's iterative method. Secondly, GSA is independent of the initial iterative value, which we prove in Theorem 1. Many numerical examples confirm GSA's robustness and efficiency.展开更多
Although the fracture behavior of sea urchin spines has been extensively investigated,there is as yet a lack of quantitative estimation on the effect of growth rings on the fracture properties of sea urchin spines.In ...Although the fracture behavior of sea urchin spines has been extensively investigated,there is as yet a lack of quantitative estimation on the effect of growth rings on the fracture properties of sea urchin spines.In sea urchin spines,much denser pores present in growth rings rather than porous layers.The tensile strength and fracture toughness of sea urchin spine samples with different numbers of growth rings are measured by the Boundary Effect Model(BEM).The experimental results of single-edge notched three-point bending tests indicate that the BEM is an appropriate method to estimate the fracture toughness of the present porous sea urchin spines,and the number of growth rings plays an important role in the fracture properties of spines.Specifically,the tensile strength and fracture toughness of sea urchin spines can be significantly improved with the increase in the number of growth rings,and their fracture toughness can even reach a relatively high value compared with some other porous materials with an identical porosity.The present research findings are expected to provide a fundamental insight into the design of high-performance bionic materials with a highly porous structure.展开更多
It is generally considered that heat treatments have a negative impact on the mechanical properties of nacre due to thermal decomposition of the organic matrix.However,the present work investigated the microindentatio...It is generally considered that heat treatments have a negative impact on the mechanical properties of nacre due to thermal decomposition of the organic matrix.However,the present work investigated the microindentation behavior on fresh and heat-treated nacres from two orthogonal directions,and the results demonstrate that both hardness value and damage tolerance can remain almost unchanged on the cross-section with the organic matrix degeneration,despite a significant deterioration on the platelet surface.Theoretical analyses suggest that the anisotropic response of indentation behavior to heat treatment in nacre is primarily caused by its structural orientation.Specifically,compared with a single layer of irregular interplatelet interfaces in cross-sectional specimens,the multiple layers of parallel interlamellar interfaces in in-plane specimens exhibit a much greater ability to impede indenter-triggered destruction,and heat treatments would reduce the in-plane hardness but nearly have no effect on the cross-sectional hardness.Moreover,the deeper embedding of platelets in cross-sectional specimens enhances their resistance to interface cracking caused by organic matrix degradation at high temperatures,leading to a reduced sensitivity to damage.Therefore,the indentation behavior of nacre shows different tendencies in response to variations in the organic matrix state along normal and parallel directions.展开更多
文摘Objective We studied the efficacy of salvage hepatectomy for treating recurrent hepatic cancer after radiofrequency ablation(RFA). Methods A retrospective analysis of 67 patients who had recurrent liver cancer after RFA treatment and received salvage hepatectomy in the Department of Hepatobiliary Surgery, Southwest Hospital, Third Military Medical University(China), from January 2006 to January 2014, was performed. The analysis included patient gender, age, hepatitis type, alpha-fetoprotein(AFP), and TNM stage prior to RFA and salvage hepatectomy, overall survival rates, and tumor-free survival rates after salvage hepatectomy. Results Among the 67 patients, there were 57 cases of hepatitis B, two cases of hepatitis C, and eight cases did not have hepatitis. AFP levels in patients ranged from 3 to 4521 ng/m L(median 33 ng/m L). Before RFA, 54 cases were stage I tumors, and 13 were stage II tumors. Tumor sizes varied from 0.82 to 4.83 cm(median 3.0 cm). In 20 cases, one RFA was performed, and for 47 cases, RFA was repeated. RFAablated region diameters ranged from 3.8 to 5.2 cm(median 4.5 cm). The interval between the salvage surgical resection and RFA was 3–37 months. Before salvage hepatectomy, 23 stage I tumors, 12 stage II tumors, and 32 stage III tumors were present(size ranged 4.83–11.84 cm; median 6.3 cm). For salvage hepatectomy, laparotomy was performed for 56 cases, and laparoscopy was performed for 28 cases. Inflow clamping was performed for 39 cases(15–45 min). Surgery was 219–370 min and intraoperative blood loss was 100–2100 m L. For 13 cases, intraoperative blood transfusion was required. Tumor pathological data revealed 31, 35, and 1 poorly, moderately, and well differentiated tumors, respectively. No patients died due to operative complications, and hospital stays were 8–10 days. Overall and tumor-free survival rates were 85% and 79% for 1 year, 50% and 20% for 3 years, and 39% and 19% for 5 years, respectively. KaplanMeier analysis and Cox regression confirmed that tumor number and size prior to salvage liver cancer were risk factors affecting survival. Conclusion Patients who received RFA to treat early-stage liver cancer with postoperative recurrent stage I tumors have satisfactory outcomes with salvage hepatectomy.
基金This work was supported by the National Natural Science Foundation of China(Grant No.51902043)the Fundamental Research Funds for the Central Universities(Grant Nos.N2102007,N2102002,and N2202011)This work was also partially supported by the National Natural Science Foundation of China(Grant Nos.51871048 and 52171108).
文摘As an essential renewable mineral resource,mollusk shells can be used as handicrafts,building materials,adsor-bents,etc.However,there are few reports on the wear resistance of their structures.The Vicker’s hardness and friction,and wear resistance of different microstructures in mollusk shells were comparatively studied in the pre-sent work.The hardness of prismatic structures is lower than that of cross-lamellar and nacreous structures.How-ever,the experimental results of sliding tests indicate that the prismatic structure exhibits the best anti-wear ability compared with foliated,crossed-lamellar,and nacreous structures.The anti-wear and hardness do not present a positive correlation,as the wear resistance properties of different microstructures in mollusk shells are governed jointly by organic matrix,structural arrangement,and basic building block actions.The present researchfindings are expected to provide fundamental insight into the design of renewable bionic materials with high wear resistance.
文摘In this paper, we present the analytical expressions for computing the minimum distance between a point and a torus, which is called the orthogonal projection point problem. If the test point is on the outside of the torus and the test point is at the center axis of the torus, we present that the orthogonal projection point set is a circle perpendicular to the center axis of the torus;if not, the analytical expression for the orthogonal projection point problem is also given. Furthermore, if the test point is in the inside of the torus, we also give the corresponding analytical expression for orthogonal projection point for two cases.
基金financially supported by the National Natural Science Foundation of China(Nos.51804072 and 52171108)the Fundamental Research Funds for the Central Universities(No.N2007012)+1 种基金the 111 Project(No.B16009)the Liaoning Revitalization Talents Program(No.xlyc1907128).
文摘A high specific Young’s modulus steel could be achieved by introducing a large fraction of kappa-carbides(κ-carbide),and its ductility was improved by efficiency divorced eutectoid transformation(DET)treatment.For this steel,carbon and aluminum contents affect not only the carbide fraction,but also the type and morphology of carbides,and consequently the mechanical properties.In this work,the alloy was designed by considering both the carbide morphology and Young’s modulus,and the carbides in the high specific Young’s modulus steels were adjusted by controlling carbon content in a suitable range for achieving a good combination of strength and ductility.The detailed microstructure evolution process during DET reaction was studied,and it was found that a higher austenitizing temperature and the cooling rate lower than 300℃ h^(−1) are suitable.The blocky carbides could be avoided by designing the carbon content in a limited content range.The microstructure-property relationship of the experimental steels was also discussed for giving an impetus to the future development of high specific Young’s modulus steels.
基金financial support from the National Natural Science Foundation of China(21571001,21631001U1532141)+2 种基金the Ministry of Education,and the Education Department of AnhuiSouthern University of Science and Technology(SUSTech),China(2020B121201002)the computational resource support from the Center for Computational Science and Engineering at SUSTech。
基金supported by the Program for New Century Excellent Talents in University,Ministry of Education,China (Grant No.NCET-07-0162)the Fundamental Research Funds for the Central Universities of China (Grant No.N090505001)supported by "The Hundred Talent Plan" of the Chinese Academy of Sciences and the National Basic Research Program of China (Grant No.2004CB619303)
基金supported by National Natural Science Foundation of China(Nos.51201027 and 51271054)Fundamental Research Funds for the Central Universities of China(Nos.N110105001,N120405001 and N120505001)
文摘Grain boundary engineering(GBE) is a practice of improving resistance to grain boundary failure of the material through increasing the proportion of low Σ coincidence site lattice(CSL) grain boundaries(special grain boundaries) in the grain boundary character distribution(GBCD). The GBCD in a cold rolled and annealed Fe-18Cr-18Mn-0.63N high-nitrogen austenitic stainless steel was analyzed by electron back scatter difraction(EBSD). The results show that the optimization process of GBE in the conventional austenitic stainless steel cannot be well applied to this high-nitrogen austenitic stainless steel. The percentage of low ΣCSL grain boundaries could increase from 47.3% for the solid solution treated high-nitrogen austenitic stainless steel specimen to 82.0% for the specimen after 5% cold rolling reduction and then annealing at 1423 K for 10 min.These special boundaries of high proportion efectively interrupt the connectivity of conventional high angle grain boundary network and thus achieve the GBCD optimization for the high-nitrogen austenitic stainless steel.
基金supported by the Key Research Program of Frontier Sciences(QYZDY-SSW-JSC031)from the Chinese Academy of Sciences(CAS)the Key Research and Development Program of Liaoning Province(201703031)+1 种基金Liaoning Science and Technology Project(20170540972)Shenyang Key R&D and Technology Transfer Program(Z17-7-023).
基金financially supported partially by the Open Foundation of Key Laboratory for Anisotropy and Texture of Materials, Ministry of Education, Northeastern University, China (No. ATM20170001)
文摘Employing the intermediate derivatization method(IDM), twenty novel 1,3,4-oxadiazole derivatives containing arylpyrazoloxyl moiety were designed and synthesized. The structures of the title compounds were identified by1 H NMR,13 C NMR, MS and elemental analyses, compound 4 was further identified by single-crystal X-ray diffraction. Antifungal activities against rice sheath blight(RSB) and sorghum anthracnose(SA) were evaluated by the mycelium linear growth rate method. Compounds 4, 16 and 20 displayed significant activities against RSB(EC50= 0.88 mg/L, 0.91 mg/L and 0.85 mg/L, respectively),higher than the reference tebuconazole; While compound 3 exhibited higher activity against SA(EC50= 1.03 mg/L), equal to commercial pyraclostrobin(EC50= 1.06 mg/L). The study showed that compound 20 is a promising fungicide for further development.
基金This research was supported by the National Research and Development Program of China(2016YFA0501103)and the National Natural Science Foundation of China(31971122 and 31570742)National Science Foundation of Hunan Province,China(2019JJ10002 and 2019JJ40096)the Research Foundation of Education Bureau of Hunan province,China(19B372).
文摘Dear Editor,Tailed,double-stranded DNA(dsDNA)bacteriophages,which belong to the order of Caudovirales,have a tail attached to a pentameric vertex of the icosahedral capsid shell(head)through a 12-fold portal(Johnson and Chiu,2007).The phages package genomic dsDNA into a round procapsid using the portal in complex with an ATP-dependent terminase complex as the motor.During packaging,the procapsid shell expands to a more angular intermediate to match the size of the viral genome(Guo et al.,2014).When the phage head is full,the portal detects internal pressure and conveys a signal from the inner capsid to the exterior,which triggers a sequence of events-the terminase complex cleaving mature DNA genome from a multi-genome concatemer,the release of the terminase complex from the portal,and the attachment of the tail complex-in the completion of phage assembly(Lander et al.,2006;Johnson and Chiu,2007).At the beginning of phage infection,the tail is responsible for receptor recognition,and the portal and tail act as a tunnel for DNA delivery into the host cytoplasm(Johnson and Chiu,2007).These mechanisms of DNA packaging and ejection may also be conserved in many other DNA viruses,including herpesvirus(Wang et al.,2020;Yang et al.,2020).
基金This work is supported by the National Natural Science Foundation of China under Grant No.61263034the Feature Key Laboratory for Regular Institutions of Higher Education of Guizhou Province of China under Grant No.[2016]003+3 种基金the Key Laboratory of Advanced Manufacturing Technology of Ministry of Education of China with Guizhou University under Grant No.KY[2018]479the Training Center for Network Security and Big Data Application of Guizhou Minzu University under Grant No.20161113006the Shandong Provincial Natural Science Foundation of China under Grant No.ZR2016GM24the Progress Project for Young Science and Technology Scholars of Guizhou Provincial Department of Education under Grant No.KY[2016]164.
文摘In this paper, we investigate how to compute the minimum distance between a point and a parametric surface, and then to return the nearest point (foot point) on the surface as well as its corresponding parameter, which is also called the point projection problem of a parametric surface. The geometric strategy algorithm (hereafter GSA) presented consists of two parts as follows. The normal curvature to a given parametric surface is used to find the corresponding foot point firstly, and then the Taylor's expansion of the parametric surface is employed to compute parameter increments and to get the iteration formula to calculate the orthogonal projection point of test point to the parametric surface. Our geometric strategy algorithm is essentially dependent on the geometric property of the normal curvature, and performs better than existing methods in two ways. Firstly, GSA converges faster than existing methods, such as the method to turn the problem into a root-finding of nonlinear system, subdividing methods, clipping methods, geometric methods (tangent vector and geometric curvature) and hybrid second-order method, etc. Specially, it converges faster than the classical Newton's iterative method. Secondly, GSA is independent of the initial iterative value, which we prove in Theorem 1. Many numerical examples confirm GSA's robustness and efficiency.
基金This work was supported by the National Natural Science Foundation of China[Grant No.51902043]the Fundamental Research Funds for the Central Universities[Grant No.N2102007,and N2102002]。
文摘Although the fracture behavior of sea urchin spines has been extensively investigated,there is as yet a lack of quantitative estimation on the effect of growth rings on the fracture properties of sea urchin spines.In sea urchin spines,much denser pores present in growth rings rather than porous layers.The tensile strength and fracture toughness of sea urchin spine samples with different numbers of growth rings are measured by the Boundary Effect Model(BEM).The experimental results of single-edge notched three-point bending tests indicate that the BEM is an appropriate method to estimate the fracture toughness of the present porous sea urchin spines,and the number of growth rings plays an important role in the fracture properties of spines.Specifically,the tensile strength and fracture toughness of sea urchin spines can be significantly improved with the increase in the number of growth rings,and their fracture toughness can even reach a relatively high value compared with some other porous materials with an identical porosity.The present research findings are expected to provide a fundamental insight into the design of high-performance bionic materials with a highly porous structure.
基金financially supported by the National Natural Science Foundation of China(Grant No.51902043)the Fundamental Research Funds for the Central Universities(Grant Nos.N2102002,N2102007 and N180203018)supported by the National Natural Science Foundation of China(No.52171108).
文摘It is generally considered that heat treatments have a negative impact on the mechanical properties of nacre due to thermal decomposition of the organic matrix.However,the present work investigated the microindentation behavior on fresh and heat-treated nacres from two orthogonal directions,and the results demonstrate that both hardness value and damage tolerance can remain almost unchanged on the cross-section with the organic matrix degeneration,despite a significant deterioration on the platelet surface.Theoretical analyses suggest that the anisotropic response of indentation behavior to heat treatment in nacre is primarily caused by its structural orientation.Specifically,compared with a single layer of irregular interplatelet interfaces in cross-sectional specimens,the multiple layers of parallel interlamellar interfaces in in-plane specimens exhibit a much greater ability to impede indenter-triggered destruction,and heat treatments would reduce the in-plane hardness but nearly have no effect on the cross-sectional hardness.Moreover,the deeper embedding of platelets in cross-sectional specimens enhances their resistance to interface cracking caused by organic matrix degradation at high temperatures,leading to a reduced sensitivity to damage.Therefore,the indentation behavior of nacre shows different tendencies in response to variations in the organic matrix state along normal and parallel directions.