Dear Editor,The conductive nanomaterials,such as carbon nanotubes(CNTs),have attracted much attention in biomedical applications.Particularly,it has been found that CNTs can promote the electrical activity of cardiomy...Dear Editor,The conductive nanomaterials,such as carbon nanotubes(CNTs),have attracted much attention in biomedical applications.Particularly,it has been found that CNTs can promote the electrical activity of cardiomyocytes,but little is known about the mechanism.^(1,2)To better understand the CNTs’biological effects on cardiomyocytes and the underlying mechanism.展开更多
Two acetate-fed sequencing batch reactors (SBR) were operated under an aerobic dynamic feeding (ADF) model (SBR#2) and with anaerobic phase before aerobic phase (SBR#1) to select mixed cultures with a high pol...Two acetate-fed sequencing batch reactors (SBR) were operated under an aerobic dynamic feeding (ADF) model (SBR#2) and with anaerobic phase before aerobic phase (SBR#1) to select mixed cultures with a high polyhydroxyalkanoates (PHA) storage response. Although kinetic selection based on storage response should bring about a predominance of floc-formers, a bulking sludge with storage response comparable to well-settled sludge was steadily established. An anaerobic phase was introduced before the aerobic phase in the ADF model to improve the sludge settleability (SBR #1), however, due to the consequent increased feast/famine ratio, the performance of SBR #1, in terms of both the maximum PHB (polyhydroxybutyrate) cell content and APHB, was lower than that of SBR #2. SBR #2 gradually reached a steady state while SBR #1 failed suddenly after 50 days of operation. The maximum specific substrate uptake rate and storage rate for the selected bulking sludge were 0.4 Cmol Ae/(Cmol X.hr) and 0.18 Cmol Ac/(Cmol PHB.hr), respectively, resulting a yield of 0.45 Cmol PHB/(Cmol Ae) in SBR #2 in the culture enrichment phase. A maximum PHB content of 53% of total suspended solids and PHB storage rate of 1.36 Cmol Ac/(Cmol PHB.hr) was achieved at 10.2 hr in batch accumulation tests under nitrogen starvation. The results indicated that it was feasible to utilize filamentous bacteria to accumulate PHA with a rate comparable to well-settled sludge, Furthermore, the lower dissolved oxygen demand of filamentous bacteria would save energy required for aeration in the culture enrichment stage.展开更多
Embryonic stem (ES) cells have the potential to develop into any type of tissue and are considered as a promising source of seeding cells for tissue engineering and transplantation therapy.The main catalyst for ES c...Embryonic stem (ES) cells have the potential to develop into any type of tissue and are considered as a promising source of seeding cells for tissue engineering and transplantation therapy.The main catalyst for ES cells differentiation is the growth into embryoid bodies (EBs),which are utilized widely as the trigger of in vitro differentiation.In this study,a novel method for generating EBs from mouse ES cells through culture in collagen/Matrigel scaffolds was successfully established.When single ES cells were seeded in three dimensional collagen/Matrigel scaffolds,they grew into aggregates gradually and formed simple EBs with circular structures.After 7 days' culture,they formed into cystic EBs that would eventually differentiate into the three embryonic germ layers.Evaluation of the EBs in terms of morphology and potential to differentiate indicated that they were typical in structure and could generate various cell types;they were also able to form into tissue-like structures.Moreover,with introduction of ascorbic acid,ES cells differentiated into cardiomyocytes efficiently and started contracting synchronously at day 19.The results demonstrated that collagen/Matrigel scaffolds supported EBs formation and their subsequent differentiation in a single three dimensional environment.展开更多
Motor timing is an important part of sensorimotor control. Previous studies have shown that beta oscillations embody the process of temporal perception in explicit timing tasks. In contrast, studies focusing on beta o...Motor timing is an important part of sensorimotor control. Previous studies have shown that beta oscillations embody the process of temporal perception in explicit timing tasks. In contrast, studies focusing on beta oscillations in implicit timing tasks are lacking. In this study, we set up an implicit motor timing task and found a modulation pattern of beta oscillations with temporal perception during movement preparation. We trained two macaques in a repetitive visually-guided reach-to-grasp task with different holding intervals. Spikes and local field potentials were recorded from microelectrode arrays in the primary motor cortex, primary somatosensory cortex, and posterior parietal cortex. We analyzed the association between beta oscillations and temporal interval in fixedduration experiments(500 ms as the Short Group and1500 ms as the Long Group) and random-duration experiments(500 ms to 1500 ms). The results showed that the peak beta frequencies in both experiments ranged from15 Hz to 25 Hz. The beta power was higher during the hold period than the movement(reach and grasp) period.Further, in the fixed-duration experiments, the mean poweras well as the maximum rate of change of beta power in the first 300 ms were higher in the Short Group than in the Long Group when aligned with the Center Hit event. In contrast, in the random-duration experiments, the corresponding values showed no statistical differences among groups. The peak latency of beta power was shorter in the Short Group than in the Long Group in the fixed-duration experiments, while no consistent modulation pattern was found in the random-duration experiments. These results indicate that beta oscillations can modulate with temporal interval in their power mode. The synchronization period of beta power could reflect the cognitive set maintaining working memory of the temporal structure and attention.展开更多
The cell-derived extracellular matrix(ECM)-modified scaffolds have advantages of mimic tissue specificity and been thought to better mimic the native cellular microenvironment in vitro.ECM derived from cardiac fibrobl...The cell-derived extracellular matrix(ECM)-modified scaffolds have advantages of mimic tissue specificity and been thought to better mimic the native cellular microenvironment in vitro.ECM derived from cardiac fibroblasts(CFs)are considered as key elements that provide a natural cell growth microenvironment and change the fate of cardiomyocytes(CMs).Here,a new hybrid scaffold is designed based on silk fibroin(SF)scaffold and CFs-derived ECM.CFs were seeded on the SF scaffold for 10days culturing and decellularized to produce CFs-derived ECM-coated SF scaffold.The results showed that the cell-derived ECM-modified silk fibroin scaffold material contained collagen,laminin,fibronectin and other ECM components with myocardial-like properties.Further to explore its effects on brown adipose stem cells(BASCs)differentiation into CMs.We found that the CFderived ECM-coated scaffold also increased the expression of CM-specific proteins(e.g.cardiac troponin T and α-actinin)of BASCs.Notably,the b1-integrin-dependent transforming growth factor-β1 signaling pathway was also involved in the regulation of CF-derived ECM by promoting the differentiation of BASCs into CMs.Overall,these findings provide insights into the bionic manufacturing of engineered cardiac tissues(ECTs)and establish a theoretical basis for the construction of ECTs.展开更多
Myocardial infarction(MI)is a worldwide disease with high incidence and high fatality rate.In the past decade,a lot of research work based on the method of cardiac tissues engineering has received wide attention from ...Myocardial infarction(MI)is a worldwide disease with high incidence and high fatality rate.In the past decade,a lot of research work based on the method of cardiac tissues engineering has received wide attention from re-searchers and has been demonstrated to have important application prospects in the treatment of MI.To make engineered cardiac tissue(ECTs)simulate the characteristics of the natural myocardial microenvironment better,the unique electrophysiological characteristics of myocardial tissue should be considered.Therefore,conductive nanomaterials are adopted to construct ECTs to make up for the lack of traditional scaffold materials.In this arti-cle,the research progresses of conductive nanomaterials application in the field of cardiac tissue engineering are summarized,and two treatment strategies of cardiac patch construction and injectable materials for MI treatment are discussed respectively.Related research work provided reference for the study of cardiac tissue engineering based conductive nanomaterials.展开更多
基金supported by the National Natural Science Foundation of China(Grant Nos.31830030)National Key Research and Development Program of China(Grant Nos.2017YFA0106100)Joint Fund project of National Natural Science Foundation of China(Grant Nos.U21A20394).
文摘Dear Editor,The conductive nanomaterials,such as carbon nanotubes(CNTs),have attracted much attention in biomedical applications.Particularly,it has been found that CNTs can promote the electrical activity of cardiomyocytes,but little is known about the mechanism.^(1,2)To better understand the CNTs’biological effects on cardiomyocytes and the underlying mechanism.
基金support of the National Special S&T Project on the Treatment and Control of Water Pollution of China (No. 2008ZX07313-003)the Science Foundation of Harbin (No. 2007RFLXS013)+1 种基金the State Key Lab of Urban Water Resource and Environment at Harbin Institute of Technology (No. 2010DX02)the National Innovation Team supported by the National Science Foundation of China (No. 50821002)
文摘Two acetate-fed sequencing batch reactors (SBR) were operated under an aerobic dynamic feeding (ADF) model (SBR#2) and with anaerobic phase before aerobic phase (SBR#1) to select mixed cultures with a high polyhydroxyalkanoates (PHA) storage response. Although kinetic selection based on storage response should bring about a predominance of floc-formers, a bulking sludge with storage response comparable to well-settled sludge was steadily established. An anaerobic phase was introduced before the aerobic phase in the ADF model to improve the sludge settleability (SBR #1), however, due to the consequent increased feast/famine ratio, the performance of SBR #1, in terms of both the maximum PHB (polyhydroxybutyrate) cell content and APHB, was lower than that of SBR #2. SBR #2 gradually reached a steady state while SBR #1 failed suddenly after 50 days of operation. The maximum specific substrate uptake rate and storage rate for the selected bulking sludge were 0.4 Cmol Ae/(Cmol X.hr) and 0.18 Cmol Ac/(Cmol PHB.hr), respectively, resulting a yield of 0.45 Cmol PHB/(Cmol Ae) in SBR #2 in the culture enrichment phase. A maximum PHB content of 53% of total suspended solids and PHB storage rate of 1.36 Cmol Ac/(Cmol PHB.hr) was achieved at 10.2 hr in batch accumulation tests under nitrogen starvation. The results indicated that it was feasible to utilize filamentous bacteria to accumulate PHA with a rate comparable to well-settled sludge, Furthermore, the lower dissolved oxygen demand of filamentous bacteria would save energy required for aeration in the culture enrichment stage.
基金supported by the National High Technology Research and Development Program of China (No 2006AA02A105 to CW)the National Nature Science Foundation of China (No 30530220)Beijing Nature Science Foundation of China (No 7062053)
文摘Embryonic stem (ES) cells have the potential to develop into any type of tissue and are considered as a promising source of seeding cells for tissue engineering and transplantation therapy.The main catalyst for ES cells differentiation is the growth into embryoid bodies (EBs),which are utilized widely as the trigger of in vitro differentiation.In this study,a novel method for generating EBs from mouse ES cells through culture in collagen/Matrigel scaffolds was successfully established.When single ES cells were seeded in three dimensional collagen/Matrigel scaffolds,they grew into aggregates gradually and formed simple EBs with circular structures.After 7 days' culture,they formed into cystic EBs that would eventually differentiate into the three embryonic germ layers.Evaluation of the EBs in terms of morphology and potential to differentiate indicated that they were typical in structure and could generate various cell types;they were also able to form into tissue-like structures.Moreover,with introduction of ascorbic acid,ES cells differentiated into cardiomyocytes efficiently and started contracting synchronously at day 19.The results demonstrated that collagen/Matrigel scaffolds supported EBs formation and their subsequent differentiation in a single three dimensional environment.
基金the International Cooperation and Exchange of the National Natural Science Foundation of China (31320103914)the General Program of the National Natural Science Foundation of China (31370987)+2 种基金the National Natural Science Foundation of China for Outstanding Young Scholars (81622027)the Beijing Nova Program of China (2016B615)the National Basic Research Development Program of China (2017YFA0106100)
文摘Motor timing is an important part of sensorimotor control. Previous studies have shown that beta oscillations embody the process of temporal perception in explicit timing tasks. In contrast, studies focusing on beta oscillations in implicit timing tasks are lacking. In this study, we set up an implicit motor timing task and found a modulation pattern of beta oscillations with temporal perception during movement preparation. We trained two macaques in a repetitive visually-guided reach-to-grasp task with different holding intervals. Spikes and local field potentials were recorded from microelectrode arrays in the primary motor cortex, primary somatosensory cortex, and posterior parietal cortex. We analyzed the association between beta oscillations and temporal interval in fixedduration experiments(500 ms as the Short Group and1500 ms as the Long Group) and random-duration experiments(500 ms to 1500 ms). The results showed that the peak beta frequencies in both experiments ranged from15 Hz to 25 Hz. The beta power was higher during the hold period than the movement(reach and grasp) period.Further, in the fixed-duration experiments, the mean poweras well as the maximum rate of change of beta power in the first 300 ms were higher in the Short Group than in the Long Group when aligned with the Center Hit event. In contrast, in the random-duration experiments, the corresponding values showed no statistical differences among groups. The peak latency of beta power was shorter in the Short Group than in the Long Group in the fixed-duration experiments, while no consistent modulation pattern was found in the random-duration experiments. These results indicate that beta oscillations can modulate with temporal interval in their power mode. The synchronization period of beta power could reflect the cognitive set maintaining working memory of the temporal structure and attention.
基金supported by the Key Program of the National Key Research and Development Program of China(nos.2017YFA0106100,2016YFY1101303)the National Natural Science Funds for Outstanding Young Scholar(no.81622027)+2 种基金the Key Program of National Natural Science Foundation of China(no.31830030)the Beijing NOVA Program of China(no.2016B615)Joint funds for National Natural Science Foundation of China(no.U1601221).
文摘The cell-derived extracellular matrix(ECM)-modified scaffolds have advantages of mimic tissue specificity and been thought to better mimic the native cellular microenvironment in vitro.ECM derived from cardiac fibroblasts(CFs)are considered as key elements that provide a natural cell growth microenvironment and change the fate of cardiomyocytes(CMs).Here,a new hybrid scaffold is designed based on silk fibroin(SF)scaffold and CFs-derived ECM.CFs were seeded on the SF scaffold for 10days culturing and decellularized to produce CFs-derived ECM-coated SF scaffold.The results showed that the cell-derived ECM-modified silk fibroin scaffold material contained collagen,laminin,fibronectin and other ECM components with myocardial-like properties.Further to explore its effects on brown adipose stem cells(BASCs)differentiation into CMs.We found that the CFderived ECM-coated scaffold also increased the expression of CM-specific proteins(e.g.cardiac troponin T and α-actinin)of BASCs.Notably,the b1-integrin-dependent transforming growth factor-β1 signaling pathway was also involved in the regulation of CF-derived ECM by promoting the differentiation of BASCs into CMs.Overall,these findings provide insights into the bionic manufacturing of engineered cardiac tissues(ECTs)and establish a theoretical basis for the construction of ECTs.
基金supported by the Key Program of the National Key Research and Development Program of China (No.2017YFA0106100,No.2016YFY1101303)Key Program of National Natural Science Foundation of China (No.31830030)Joint Funds for National Natural Science Foundation of China (No.U1601221).
文摘Myocardial infarction(MI)is a worldwide disease with high incidence and high fatality rate.In the past decade,a lot of research work based on the method of cardiac tissues engineering has received wide attention from re-searchers and has been demonstrated to have important application prospects in the treatment of MI.To make engineered cardiac tissue(ECTs)simulate the characteristics of the natural myocardial microenvironment better,the unique electrophysiological characteristics of myocardial tissue should be considered.Therefore,conductive nanomaterials are adopted to construct ECTs to make up for the lack of traditional scaffold materials.In this arti-cle,the research progresses of conductive nanomaterials application in the field of cardiac tissue engineering are summarized,and two treatment strategies of cardiac patch construction and injectable materials for MI treatment are discussed respectively.Related research work provided reference for the study of cardiac tissue engineering based conductive nanomaterials.