Porosity,a key parameter in assessing the physical properties of shale reservoirs and the reserves,is of great significance to the selection and evaluation of shale sweet spots.There are many methods at present to cha...Porosity,a key parameter in assessing the physical properties of shale reservoirs and the reserves,is of great significance to the selection and evaluation of shale sweet spots.There are many methods at present to characterize shale porosity,most of which are aimed at post-core cleaning shale,such as those involving helium and saturated fluid(namely liquid-involved porosimetry).However,due to the low efficiency of shale core cleaning and the possible damage to pore structure during the core cleaning process,it's hard to guarantee the accuracy of porosity measurement.In this regard,we resort to the two-dimensional(2D)nuclear magnetic resonance(NMR)technology of T1-T2 in characterizing the primary shale porosity with samples taken from pressure coring in the 4th member of Shahejie Formation(Sha 4 Member)in well Fanxie 184 in the Jiyang Depression.Moreover,comparative experiments of shale porosity measurement by three methods,namely the simultaneous distillation extraction(SDE),helium and fluid measurement,are carried out simultaneously.The results show that the values obtained by SDE,gas and liquid measurement are similar,which are about 0.6 times of 2D NMR porosimetry.Core cleaning efficiency tends to seriously affect the results involving gas and liquid.In addition,the core cleaning treatment is bound to change the shale pore structure,and this is especially true in clay which tends to swell;consequently,porosity results are to be distorted by gas and liquid methods.It is thereby recommended to utilize the 2D NMR technology to characterize the primary total porosity of shale samples without core cleaning.The effective porosity of samples from pressure coring is determined by T2 cutoff value of around 0.3 ms.展开更多
Tumor cell invasion is the key driver of metastatic dissemination,resulting in the development and progression of metastatic tumors at secondary sites,and remains the major cause of cancer-related death.Recent studies...Tumor cell invasion is the key driver of metastatic dissemination,resulting in the development and progression of metastatic tumors at secondary sites,and remains the major cause of cancer-related death.Recent studies suggest that,in addition to protease-mediated degradation and chemotaxis-stimulated migration,tumor invasion is significantly influenced by physical surroundings.How tumor cells decode information about their shape deformation under mechanical stress and adapt their dynamic behavior to escape the confined regions remains largely unknown.This review highlights recent findings that illustrate mechanical cues in confined tumor microenvironment contribute to tumor progression.We also systematically discuss the role of compression-induced deformation in cell membrane topology and cytoskeletal remodeling,as well as its biophysical mechanisms in regulating tumor invasion from a biomechanical perspective.展开更多
Since human coronavirus(HCoVs)was first described in the 1960s,seven strains of respiratory human coronaviruses have emerged and caused human infections.After the emergence of severe acute respiratory syndrome coronav...Since human coronavirus(HCoVs)was first described in the 1960s,seven strains of respiratory human coronaviruses have emerged and caused human infections.After the emergence of severe acute respiratory syndrome coronavirus(SARS-CoV)and Middle East respiratory syndrome coronavirus(MERS-CoV),a pneumonia outbreak of coronavirus disease 2019(COVID-19)caused by a novel coronavirus(SARS-CoV-2)has represented a pandemic threat to global public health in the 21st century.Without effectively prophylactic and therapeutic strategies including vaccines and antiviral drugs,these three coronaviruses have caused severe respiratory syndrome and high case-fatality rates around the world.In this review,we detail the emergence event,origin and reservoirs of all HCoVs,compare the differences with regard to structure and receptor usage,and summarize therapeutic strategies for COVID-19 that cause severe pneumonia and global pandemic.展开更多
基金funded by the National Natural Science Foundation of China(No.41922015,No.42072147)the Foundation Research Funds for the Central Universities(No.20CX06085A).
文摘Porosity,a key parameter in assessing the physical properties of shale reservoirs and the reserves,is of great significance to the selection and evaluation of shale sweet spots.There are many methods at present to characterize shale porosity,most of which are aimed at post-core cleaning shale,such as those involving helium and saturated fluid(namely liquid-involved porosimetry).However,due to the low efficiency of shale core cleaning and the possible damage to pore structure during the core cleaning process,it's hard to guarantee the accuracy of porosity measurement.In this regard,we resort to the two-dimensional(2D)nuclear magnetic resonance(NMR)technology of T1-T2 in characterizing the primary shale porosity with samples taken from pressure coring in the 4th member of Shahejie Formation(Sha 4 Member)in well Fanxie 184 in the Jiyang Depression.Moreover,comparative experiments of shale porosity measurement by three methods,namely the simultaneous distillation extraction(SDE),helium and fluid measurement,are carried out simultaneously.The results show that the values obtained by SDE,gas and liquid measurement are similar,which are about 0.6 times of 2D NMR porosimetry.Core cleaning efficiency tends to seriously affect the results involving gas and liquid.In addition,the core cleaning treatment is bound to change the shale pore structure,and this is especially true in clay which tends to swell;consequently,porosity results are to be distorted by gas and liquid methods.It is thereby recommended to utilize the 2D NMR technology to characterize the primary total porosity of shale samples without core cleaning.The effective porosity of samples from pressure coring is determined by T2 cutoff value of around 0.3 ms.
基金supported by the Beijing Natural Science Foundation(China)(No.L248062)the Fundamental Research Funds for the Central Universities of China(No.KG16301601).
文摘Tumor cell invasion is the key driver of metastatic dissemination,resulting in the development and progression of metastatic tumors at secondary sites,and remains the major cause of cancer-related death.Recent studies suggest that,in addition to protease-mediated degradation and chemotaxis-stimulated migration,tumor invasion is significantly influenced by physical surroundings.How tumor cells decode information about their shape deformation under mechanical stress and adapt their dynamic behavior to escape the confined regions remains largely unknown.This review highlights recent findings that illustrate mechanical cues in confined tumor microenvironment contribute to tumor progression.We also systematically discuss the role of compression-induced deformation in cell membrane topology and cytoskeletal remodeling,as well as its biophysical mechanisms in regulating tumor invasion from a biomechanical perspective.
基金This work was supported by the National Natural Science Foundation of China(11902020,31370018,11421202,and 11827803)China Postdoctoral Science Foundation(No.2019M660390)+1 种基金the National Key R&D Program of China(2017YFA0506500,2016YFC1102203,and 2016YFC1101100)Fundamental Research Funds for the Central Universities(ZG140S1971).
文摘Since human coronavirus(HCoVs)was first described in the 1960s,seven strains of respiratory human coronaviruses have emerged and caused human infections.After the emergence of severe acute respiratory syndrome coronavirus(SARS-CoV)and Middle East respiratory syndrome coronavirus(MERS-CoV),a pneumonia outbreak of coronavirus disease 2019(COVID-19)caused by a novel coronavirus(SARS-CoV-2)has represented a pandemic threat to global public health in the 21st century.Without effectively prophylactic and therapeutic strategies including vaccines and antiviral drugs,these three coronaviruses have caused severe respiratory syndrome and high case-fatality rates around the world.In this review,we detail the emergence event,origin and reservoirs of all HCoVs,compare the differences with regard to structure and receptor usage,and summarize therapeutic strategies for COVID-19 that cause severe pneumonia and global pandemic.
