Reactive oxygen species have been implicated in conditions ranging from cardiovascular dysfunc- tion, arthritis, cancer, to aging and age-related disorders. The organism developed several path- ways to counteract thes...Reactive oxygen species have been implicated in conditions ranging from cardiovascular dysfunc- tion, arthritis, cancer, to aging and age-related disorders. The organism developed several path- ways to counteract these effects, with base excision repair being responsible for repairing one of the major base lesions （8-oxoG） in all organisms. Epidemiological evidence suggests that cognitive stimulation makes the brain more resilient to damage or degeneration. Recent studies have linked enriched environment to reduction of oxidative stressin neurons of mice with Alzheimer＇s dis- ease-like disease, but given its complexity it is not clear what specific aspect of enriched environ- ment has therapeutic effects. Studies from molecular biology have shown that the protein p300, which is a transcription co-activator required for consolidation of memories during specific learning tasks, is at the same time involved in DNA replication and repair, playing a central role in the long-patch pathway of base excision repair. Based on the evidence, we propose that learning tasks such as novel object recognition could be tested as possible methods of base excision repair fa- cilitation, hence inducing DNA repair in the hippocampal neurons. If this method proves to be effec- tive, it could be the start for designing similar tasks for humans, as a behavioral therapeutic com- plement to the classical drug-based therapy in treating neurodegenerative disorders.展开更多
Stable integration of hydrogel implants with host tissues is of critical importance to cartilage tissue engineering.Designing and fabricating hydrogels with high adhesive strength,stability and regeneration potential ...Stable integration of hydrogel implants with host tissues is of critical importance to cartilage tissue engineering.Designing and fabricating hydrogels with high adhesive strength,stability and regeneration potential are major challenges to be overcome.This study fabricated injectable adhesive hyaluronic acid(HA)hydrogel modified by aldehyde groups and methacrylate(AHAMA)on the polysaccharide backbone with multiple anchoring mechanisms(amide bond through the dynamic Schiff base reaction,hydrogen bond and physical interpenetration).AHAMA hydrogel exhibited significantly improved durability and stability within a humid environment(at least 7 days),together with higher adhesive strength(43 KPa to skin and 52 KPa to glass),as compared to commercial fibrin glue(nearly 10 KPa)and HAMA hydrogel(nearly 20 KPa).The results showed that AHAMA hydrogel was biocompatible and could be easily and rapidly prepared in situ.In vitro cell culture experiments showed that AHAMA hydrogel could enhance proliferation(1.2-folds after 3 days)and migration(1.5-folds after 12 h)of bone marrow stem cells(BMSCs),as compared to cells cultured in a culture dish.Furthermore,in a rat osteochondral defect model,implanted AHAMA hydrogel significantly promoted integration between neo-cartilage and host tissues,and significantly improved cartilage regeneration(modified O’Driscoll histological scores of 16.0±4.1 and 18.3±4.6 after 4 and 12-weeks of post-implantation in AHAMA groups respectively,12.0±2.7 and 12.2±2.8 respectively in HAMA groups,9.8±2.4 and 11.5±2.1 respectively in untreated groups).Hence,AHAMA hydrogel is a promising adhesive biomaterial for clinical cartilage regeneration and other biomedical applications.展开更多
In this study,the regenerative effects of different regenerants on aged SBS-modified asphalt from different perspectives were investigated,including their conventional properties,viscoelastic behavior,creep-related pr...In this study,the regenerative effects of different regenerants on aged SBS-modified asphalt from different perspectives were investigated,including their conventional properties,viscoelastic behavior,creep-related properties,and micromorphology.Base oils composed of different proportions of aromatic and saturated hydrocarbons as well as the styrene-butadiene-styrene(SBS)restorer were used to prepare the regenerants.The results showed that the components of the base oil of the regenerant played a crucial role in determining the characteristics and performance of the recycled SBSmodified asphalt.Regenerants containing a high proportion of aromatics dissolved the hard segment in the SBS restorer,thereby delaying the effect of a reduction in the regenerants on the performance of the aged asphalts at a high temperature.Regenerants containing a high proportion of saturates dissolved the soft segment in the SBS restorer to enhance the lowtemperature performance of the recycled asphalts.In addition,the stress sensitivity of the recycled asphalts increased with the fraction of aromatics in the regenerant.As the aromatic content of the base oil components of the regenerants increased and their saturate content decreased,the state of dispersion of the SBS phase in the recycled SBS-modified asphalts improved.The optimal content of aromatics in the base oil of the regenerants should be set in the range of 33%to 47%to ensure the adequate performance of the recycled asphalts and a high efficiency of the SBS restorer.展开更多
In an attempt to propagate and conserve the rare, showy bulbous plants of Iris bismarckiana, newly recorded to the flora of Jordan and to contribute to the conservation the wild lris species in Jordan, a simple rapid,...In an attempt to propagate and conserve the rare, showy bulbous plants of Iris bismarckiana, newly recorded to the flora of Jordan and to contribute to the conservation the wild lris species in Jordan, a simple rapid, time consuming protocol has been developed using plant regeneration via somatic embryogenesis. Somatic embryogenesis was induced in zygotic embryo culture on Murashige and Skoog （MS） medium supplemented with 2,4-dichlorophenoxy acetic acid （8 mg/L） as the sole plant growth regulator, where both embryogenesis calli and somatic embryos were induced. Separation of embryos from embryo clusters was necessary to enhance the frequency of germination. Germination was stimulated by separation of embryos successfully from embryo clusters and transferred onto fresh MS medium. Data obtained were analyzed as a complete random design with three replications. Calli fragments that were transferred to embryogenesis induction medium （EIM） produced white embryo-like globular structures within two weeks. Within three more weeks, clusters of structures at various stages of development could be found on the same callus. The applied technique is rewarding and encouraging for further research on the endangered wild species of Iris in Jordan.展开更多
基金supported by a grant from Synergon Consulting Companya grant from Romanian Ministry for Education and Research,No.PCCE 140/2008
文摘Reactive oxygen species have been implicated in conditions ranging from cardiovascular dysfunc- tion, arthritis, cancer, to aging and age-related disorders. The organism developed several path- ways to counteract these effects, with base excision repair being responsible for repairing one of the major base lesions （8-oxoG） in all organisms. Epidemiological evidence suggests that cognitive stimulation makes the brain more resilient to damage or degeneration. Recent studies have linked enriched environment to reduction of oxidative stressin neurons of mice with Alzheimer＇s dis- ease-like disease, but given its complexity it is not clear what specific aspect of enriched environ- ment has therapeutic effects. Studies from molecular biology have shown that the protein p300, which is a transcription co-activator required for consolidation of memories during specific learning tasks, is at the same time involved in DNA replication and repair, playing a central role in the long-patch pathway of base excision repair. Based on the evidence, we propose that learning tasks such as novel object recognition could be tested as possible methods of base excision repair fa- cilitation, hence inducing DNA repair in the hippocampal neurons. If this method proves to be effec- tive, it could be the start for designing similar tasks for humans, as a behavioral therapeutic com- plement to the classical drug-based therapy in treating neurodegenerative disorders.
基金This work was supported by the National Natural Science Foundation of China grant(81772334)Peking University Medicine Seed Fund for Interdisciplinary Research(BMU2018ME001).
文摘Stable integration of hydrogel implants with host tissues is of critical importance to cartilage tissue engineering.Designing and fabricating hydrogels with high adhesive strength,stability and regeneration potential are major challenges to be overcome.This study fabricated injectable adhesive hyaluronic acid(HA)hydrogel modified by aldehyde groups and methacrylate(AHAMA)on the polysaccharide backbone with multiple anchoring mechanisms(amide bond through the dynamic Schiff base reaction,hydrogen bond and physical interpenetration).AHAMA hydrogel exhibited significantly improved durability and stability within a humid environment(at least 7 days),together with higher adhesive strength(43 KPa to skin and 52 KPa to glass),as compared to commercial fibrin glue(nearly 10 KPa)and HAMA hydrogel(nearly 20 KPa).The results showed that AHAMA hydrogel was biocompatible and could be easily and rapidly prepared in situ.In vitro cell culture experiments showed that AHAMA hydrogel could enhance proliferation(1.2-folds after 3 days)and migration(1.5-folds after 12 h)of bone marrow stem cells(BMSCs),as compared to cells cultured in a culture dish.Furthermore,in a rat osteochondral defect model,implanted AHAMA hydrogel significantly promoted integration between neo-cartilage and host tissues,and significantly improved cartilage regeneration(modified O’Driscoll histological scores of 16.0±4.1 and 18.3±4.6 after 4 and 12-weeks of post-implantation in AHAMA groups respectively,12.0±2.7 and 12.2±2.8 respectively in HAMA groups,9.8±2.4 and 11.5±2.1 respectively in untreated groups).Hence,AHAMA hydrogel is a promising adhesive biomaterial for clinical cartilage regeneration and other biomedical applications.
基金the National Key R&D Program of China(2021YFB2601200)the Science and Technology Project of Department of Communication of Zhejiang Province(2021043).
文摘In this study,the regenerative effects of different regenerants on aged SBS-modified asphalt from different perspectives were investigated,including their conventional properties,viscoelastic behavior,creep-related properties,and micromorphology.Base oils composed of different proportions of aromatic and saturated hydrocarbons as well as the styrene-butadiene-styrene(SBS)restorer were used to prepare the regenerants.The results showed that the components of the base oil of the regenerant played a crucial role in determining the characteristics and performance of the recycled SBSmodified asphalt.Regenerants containing a high proportion of aromatics dissolved the hard segment in the SBS restorer,thereby delaying the effect of a reduction in the regenerants on the performance of the aged asphalts at a high temperature.Regenerants containing a high proportion of saturates dissolved the soft segment in the SBS restorer to enhance the lowtemperature performance of the recycled asphalts.In addition,the stress sensitivity of the recycled asphalts increased with the fraction of aromatics in the regenerant.As the aromatic content of the base oil components of the regenerants increased and their saturate content decreased,the state of dispersion of the SBS phase in the recycled SBS-modified asphalts improved.The optimal content of aromatics in the base oil of the regenerants should be set in the range of 33%to 47%to ensure the adequate performance of the recycled asphalts and a high efficiency of the SBS restorer.
文摘In an attempt to propagate and conserve the rare, showy bulbous plants of Iris bismarckiana, newly recorded to the flora of Jordan and to contribute to the conservation the wild lris species in Jordan, a simple rapid, time consuming protocol has been developed using plant regeneration via somatic embryogenesis. Somatic embryogenesis was induced in zygotic embryo culture on Murashige and Skoog （MS） medium supplemented with 2,4-dichlorophenoxy acetic acid （8 mg/L） as the sole plant growth regulator, where both embryogenesis calli and somatic embryos were induced. Separation of embryos from embryo clusters was necessary to enhance the frequency of germination. Germination was stimulated by separation of embryos successfully from embryo clusters and transferred onto fresh MS medium. Data obtained were analyzed as a complete random design with three replications. Calli fragments that were transferred to embryogenesis induction medium （EIM） produced white embryo-like globular structures within two weeks. Within three more weeks, clusters of structures at various stages of development could be found on the same callus. The applied technique is rewarding and encouraging for further research on the endangered wild species of Iris in Jordan.
