The physiologic and pathologic cellular and molecular changes occurring with age in the human colon affect both the inflammatory process leading to mucosal injury and the regenerative capacity of the epithelium.On the...The physiologic and pathologic cellular and molecular changes occurring with age in the human colon affect both the inflammatory process leading to mucosal injury and the regenerative capacity of the epithelium.On the one hand,age-related telomere shortening and inflamm-ageing may lead to the development of colonic inflammation,which results in epithelial damage.On the other hand,the altered migration and function of regenerative stem cells,the age-related methylation of mucosal healing-associated genes,together with the alterations of growth factor signaling with age,may be involved in delayed mucosal regeneration.The connections of these alterations to the process of ageing are not fully known.The understanding and customtailored modification of these mechanisms are of great clinical importance with regard to disease prevention and modern therapeutic strategies.Here,we aim to summarize the age-related microscopic and molecular changes of the human colon,as well as their role in altered mucosal healing.展开更多
Pseudobulbar paralysis is a kind of common clinical syndromes of cerebral vascular diseases, which is manifested as dyslalia, dysphagia and choking. By several-year clinical observations, 36 cases were treated with sa...Pseudobulbar paralysis is a kind of common clinical syndromes of cerebral vascular diseases, which is manifested as dyslalia, dysphagia and choking. By several-year clinical observations, 36 cases were treated with satisfactory therapeutic effects as reported in the following.Clinical DataOf 36 in-patients, there were 24 males and 12 females, aged from 44 to 81 years, averaging 64.92 years. Of 36 cases, 24 were at the acute stage and 12 at the recovery stage. All the cases were diagnosed as cerebral vascular diseases by cranial CT scan and MRI, of which, 4 were cerebral infarction, 26 lacunar cerebral infarction, 5 cerebral hemorrhage and 1 mixed type. Of 36 cases, 15 were the first attack of wind-stroke, 15 the second attack, 5 the third attack and 1 the forth attack. There were 26 patients with hypertension among 36 cases, of which, 8 patients suffered from hypertension within 10 years, 6 for more than 10 years, 9 for more than 20 years and 3 for more than 30 years. All the 36 cases were associated with dysphagia and agreeable to Standard on Diagnosis and Evaluation of Therapeutic Effects of Wind-stroke issued by the State Scientific Committee 85-919-01-01, 1995.展开更多
In recent decades,the damage and economic losses caused by climate change and extreme climate events have been increasing rapidly.Although scientists all over the world have made great efforts to understand and predic...In recent decades,the damage and economic losses caused by climate change and extreme climate events have been increasing rapidly.Although scientists all over the world have made great efforts to understand and predict climatic variations,there are still several major problems for improving climate prediction.In 2020,the Center for Climate System Prediction Research(CCSP) was established with support from the National Natural Science Foundation of China.CCSP aims to tackle three scientific problems related to climate prediction—namely,El Ni?o-Southern Oscillation(ENSO) prediction,extended-range weather forecasting,and interannual-to-decadal climate prediction—and hence provide a solid scientific basis for more reliable climate predictions and disaster prevention.In this paper,the major objectives and scientific challenges of CCSP are reported,along with related achievements of its research groups in monsoon dynamics,land-atmosphere interaction and model development,ENSO variability,intraseasonal oscillation,and climate prediction.CCSP will endeavor to tackle key scientific problems in these areas.展开更多
Estimation of fire cycle has been conducted by using the negative exponential function as an approximation of time-since-fire distribution of a landscape assumed to be homogeneous with respect to fire spread processes...Estimation of fire cycle has been conducted by using the negative exponential function as an approximation of time-since-fire distribution of a landscape assumed to be homogeneous with respect to fire spread processes. The authors imposed predefined fire cycles on a virtual landscape of 100 cell×100 cell, and obtained a mosaic composing of patches with different stand ages (i.e. time since fire). Graphical and statistical methods (Van Wagner 1978; Reed et al. 1998) were employed to derive fire cycle from the virtual landscape. By comparing the predefined and the derived fire cycles, the two methods and tested the effects of sample size and hazard of burning (i.e., stand's susceptibility to fire in relation to its stand age) were evaluated on fire cycle deviation. The simulation results indicated a minimum sample size of l0 times of the annual burnt area would be required for.partitioning time-since-fire distribution into homogeneous epochs indicating temporal change in fire cycle. Statistically, there was significant difference among the imposed and the derived fire cycle, regardless of sample sizes with or without consideration of hazard of burning. Both methods underestimated the more recent fire cycle without significant difference between them. The results imply that deviation of fire cycle based on time-since-fire distribution warrants cautious interpretation, especially when a landscape is spatially partitioned into small units and temporal changes in fire cycle are involved.展开更多
Purpose: To study the management and evaluate anatomical and functional outcomes of patients with ipsilateral proximal and shaft femoral fractures. Methods: A retrospective, descriptive and analytic study lasted for...Purpose: To study the management and evaluate anatomical and functional outcomes of patients with ipsilateral proximal and shaft femoral fractures. Methods: A retrospective, descriptive and analytic study lasted for ten years and a half ranging from January 1, 2005 to June 30, 2015. The following parameters were studied: epidemiology, fracture char- acteristics, therapeutic, anatomical and functional outcomes. The correlation between different param- eters was analyzed with Fischer test. The significant threshold was defined for p value 〈0.05. Results: Ten medical files were registered. There were 7 men and 3 women, with a sex ratio of 2.33. The average age was 46 years (range: 29-62 years). It was about traffic road accidents in all cases. Motorcycle -motorcycle and motorcycle-car collision were most frequent. Average admission delay was 7 h (range: 1.5-24 h). Left side was most reached in 8 cases. According to Garden classification, there was type Ⅲ cervical fracture in 2 cases, type Ⅱ in 1 case and type Ⅳ in 1 case. According to Ender classification, there was type I trochanteric fracture in 3 cases, type Ⅵ in 2 cases and type Ⅶ in 1 case. According to AO classification, there was type A shaft fracture in 6 cases (A2 in 4 cases and A3 in 2 cases), type B in 2 cases (BI in 1 case and B2 in 1 case) and type C in 2 cases (CI in 1 case and C2 in 1 case). Average surgical delay was 28.7 days (range: 11-61 days). For proximal femoral fracture, Moore prosthesis was used in 1 case, blade plate 130° in 2 cases, long Gamma nail in 4 cases, double screwing in 2 cases and dynamic hip screw in 1 case. For shaft femoral fracture, blade plate 95° was used in 3 cases, low compressive plate in 2 cases. Osseous contention was achieved in 4 cases with long Gamma nail and in 1 case with long blade plate 130°. Nonunion of cervical fracture was achieved in 2 cases. The average osseous healing delay was 5.14 months (range: 3-12 months) for proximal femoral fracture and 5 months (range: 3-8 months) for shaft femoral fractures. According to Friedman and Wyman criteria, functional results were good in 4 cases, average in 4 cases and bad in 2 cases. Regarding implants, healing delay showed no statistic difference between one-implant group and two-implant group (p = 0.52), and among the patients with different functional outcomes (p = 0.52). Functional outcomes showed no statistic difference between one-implant group and two-implant group (p = 0.46). Conclusion: Ipsilateral proximal and shaft femoral fractures are relatively uncommon in our daily ac- tivities. It is difficult to recognize proximal femoral fractures which are unnoticed. Results are generally good if the doctors take the two fractures into account in the management.展开更多
Objective: Supracondylar fractures of the humerus account for 60% of all the fractures around the pediatric elbow and even in developed countries 18% of patients undergo surgery 48 hours or longer following presentat...Objective: Supracondylar fractures of the humerus account for 60% of all the fractures around the pediatric elbow and even in developed countries 18% of patients undergo surgery 48 hours or longer following presentation in the hospital. Management guidelines are not clear yet for these patients who present late. The aim of this prospective study was to evaluate the clinical, radiological and functional outcome following closed reduction and percutaneous pinning of widely displaced supracondylar fractures of the humerus presenting 12 hours or more after injury.Methods: We reviewed the functional and radiological results of closed reduction and percutaneous pinning using crossed K-wires in 40 patients with displaced extension type supracondylar fracture of the humerus (Gartland type Ⅲ) with a delay of more than 12 hours in presentation. The average age of patients was 4.5 years and the mean delay in presentation was 17.55 hours.Results: Closed reduction and percutaneous pinning was successful in 90% of patients. The mean follow up period was 15 months. The Baumann's angle was restored within 4 degrees of the unaffected side in all patients. Use of a small medial incision in patients with severe swelling helped us avoid ulnar nerve injury. Using Flynn's criteria,38 patients (95%) had an excellent result. Two patients had mild myositis and both had a poor result. None of the patients developed cubitus varus.Conclusion: Closed reduction and crossed pinning of displaced supracondylar fractures of humerus in children is a safe and effective method even with delayed presentation.展开更多
Objective: To explore chemical component changes of dog bone at different lengthening time and in different bone regions of interest, and to evaluate the mineralization during Ilizarov lengthening process. Methods: Th...Objective: To explore chemical component changes of dog bone at different lengthening time and in different bone regions of interest, and to evaluate the mineralization during Ilizarov lengthening process. Methods: The ash weight, the concentrations of calcium, phosphorus and the calcium/phosphorus ratio were measured at different intervals (2, 4, 6, 8, 12 weeks) since lengthening and the lengthened part was compared with a control area at each interval. Results: The ash weight, the concentrations of calcium and phosphorus in the lengthened area differed at all development time. The calcium/phosphorus (Ca/P) ratio in the lengthened region remained significantly lower than that in the control region up to 12 weeks after the lengthening. Conclusions: These results suggest that also other inorganic ions play an important role in the mineralization process and that they become relatively more important since 8 weeks after the lengthening.展开更多
We propose and study a predator prey model with state-dependent delay where the prey population is assumed to have an age structure. The state-dependent delay appears due to the mature condition that the prey must spe...We propose and study a predator prey model with state-dependent delay where the prey population is assumed to have an age structure. The state-dependent delay appears due to the mature condition that the prey must spend an amount of time in the immature stage sufficient to accumulate a threshold amount of food. We perform a qualitative analysis of the solutions, which includes studying positivity and boundedness, existence and local stability of equilibria. For the global dynamics of the system, we discuss an attracting region which is determined by solutions, and the region collapses to the interior equilibrium in the constant delay case.展开更多
文摘The physiologic and pathologic cellular and molecular changes occurring with age in the human colon affect both the inflammatory process leading to mucosal injury and the regenerative capacity of the epithelium.On the one hand,age-related telomere shortening and inflamm-ageing may lead to the development of colonic inflammation,which results in epithelial damage.On the other hand,the altered migration and function of regenerative stem cells,the age-related methylation of mucosal healing-associated genes,together with the alterations of growth factor signaling with age,may be involved in delayed mucosal regeneration.The connections of these alterations to the process of ageing are not fully known.The understanding and customtailored modification of these mechanisms are of great clinical importance with regard to disease prevention and modern therapeutic strategies.Here,we aim to summarize the age-related microscopic and molecular changes of the human colon,as well as their role in altered mucosal healing.
文摘Pseudobulbar paralysis is a kind of common clinical syndromes of cerebral vascular diseases, which is manifested as dyslalia, dysphagia and choking. By several-year clinical observations, 36 cases were treated with satisfactory therapeutic effects as reported in the following.Clinical DataOf 36 in-patients, there were 24 males and 12 females, aged from 44 to 81 years, averaging 64.92 years. Of 36 cases, 24 were at the acute stage and 12 at the recovery stage. All the cases were diagnosed as cerebral vascular diseases by cranial CT scan and MRI, of which, 4 were cerebral infarction, 26 lacunar cerebral infarction, 5 cerebral hemorrhage and 1 mixed type. Of 36 cases, 15 were the first attack of wind-stroke, 15 the second attack, 5 the third attack and 1 the forth attack. There were 26 patients with hypertension among 36 cases, of which, 8 patients suffered from hypertension within 10 years, 6 for more than 10 years, 9 for more than 20 years and 3 for more than 30 years. All the 36 cases were associated with dysphagia and agreeable to Standard on Diagnosis and Evaluation of Therapeutic Effects of Wind-stroke issued by the State Scientific Committee 85-919-01-01, 1995.
基金supported by the National Natural Science Foundation of China [grant number 42088101]。
文摘In recent decades,the damage and economic losses caused by climate change and extreme climate events have been increasing rapidly.Although scientists all over the world have made great efforts to understand and predict climatic variations,there are still several major problems for improving climate prediction.In 2020,the Center for Climate System Prediction Research(CCSP) was established with support from the National Natural Science Foundation of China.CCSP aims to tackle three scientific problems related to climate prediction—namely,El Ni?o-Southern Oscillation(ENSO) prediction,extended-range weather forecasting,and interannual-to-decadal climate prediction—and hence provide a solid scientific basis for more reliable climate predictions and disaster prevention.In this paper,the major objectives and scientific challenges of CCSP are reported,along with related achievements of its research groups in monsoon dynamics,land-atmosphere interaction and model development,ENSO variability,intraseasonal oscillation,and climate prediction.CCSP will endeavor to tackle key scientific problems in these areas.
文摘Estimation of fire cycle has been conducted by using the negative exponential function as an approximation of time-since-fire distribution of a landscape assumed to be homogeneous with respect to fire spread processes. The authors imposed predefined fire cycles on a virtual landscape of 100 cell×100 cell, and obtained a mosaic composing of patches with different stand ages (i.e. time since fire). Graphical and statistical methods (Van Wagner 1978; Reed et al. 1998) were employed to derive fire cycle from the virtual landscape. By comparing the predefined and the derived fire cycles, the two methods and tested the effects of sample size and hazard of burning (i.e., stand's susceptibility to fire in relation to its stand age) were evaluated on fire cycle deviation. The simulation results indicated a minimum sample size of l0 times of the annual burnt area would be required for.partitioning time-since-fire distribution into homogeneous epochs indicating temporal change in fire cycle. Statistically, there was significant difference among the imposed and the derived fire cycle, regardless of sample sizes with or without consideration of hazard of burning. Both methods underestimated the more recent fire cycle without significant difference between them. The results imply that deviation of fire cycle based on time-since-fire distribution warrants cautious interpretation, especially when a landscape is spatially partitioned into small units and temporal changes in fire cycle are involved.
文摘Purpose: To study the management and evaluate anatomical and functional outcomes of patients with ipsilateral proximal and shaft femoral fractures. Methods: A retrospective, descriptive and analytic study lasted for ten years and a half ranging from January 1, 2005 to June 30, 2015. The following parameters were studied: epidemiology, fracture char- acteristics, therapeutic, anatomical and functional outcomes. The correlation between different param- eters was analyzed with Fischer test. The significant threshold was defined for p value 〈0.05. Results: Ten medical files were registered. There were 7 men and 3 women, with a sex ratio of 2.33. The average age was 46 years (range: 29-62 years). It was about traffic road accidents in all cases. Motorcycle -motorcycle and motorcycle-car collision were most frequent. Average admission delay was 7 h (range: 1.5-24 h). Left side was most reached in 8 cases. According to Garden classification, there was type Ⅲ cervical fracture in 2 cases, type Ⅱ in 1 case and type Ⅳ in 1 case. According to Ender classification, there was type I trochanteric fracture in 3 cases, type Ⅵ in 2 cases and type Ⅶ in 1 case. According to AO classification, there was type A shaft fracture in 6 cases (A2 in 4 cases and A3 in 2 cases), type B in 2 cases (BI in 1 case and B2 in 1 case) and type C in 2 cases (CI in 1 case and C2 in 1 case). Average surgical delay was 28.7 days (range: 11-61 days). For proximal femoral fracture, Moore prosthesis was used in 1 case, blade plate 130° in 2 cases, long Gamma nail in 4 cases, double screwing in 2 cases and dynamic hip screw in 1 case. For shaft femoral fracture, blade plate 95° was used in 3 cases, low compressive plate in 2 cases. Osseous contention was achieved in 4 cases with long Gamma nail and in 1 case with long blade plate 130°. Nonunion of cervical fracture was achieved in 2 cases. The average osseous healing delay was 5.14 months (range: 3-12 months) for proximal femoral fracture and 5 months (range: 3-8 months) for shaft femoral fractures. According to Friedman and Wyman criteria, functional results were good in 4 cases, average in 4 cases and bad in 2 cases. Regarding implants, healing delay showed no statistic difference between one-implant group and two-implant group (p = 0.52), and among the patients with different functional outcomes (p = 0.52). Functional outcomes showed no statistic difference between one-implant group and two-implant group (p = 0.46). Conclusion: Ipsilateral proximal and shaft femoral fractures are relatively uncommon in our daily ac- tivities. It is difficult to recognize proximal femoral fractures which are unnoticed. Results are generally good if the doctors take the two fractures into account in the management.
文摘Objective: Supracondylar fractures of the humerus account for 60% of all the fractures around the pediatric elbow and even in developed countries 18% of patients undergo surgery 48 hours or longer following presentation in the hospital. Management guidelines are not clear yet for these patients who present late. The aim of this prospective study was to evaluate the clinical, radiological and functional outcome following closed reduction and percutaneous pinning of widely displaced supracondylar fractures of the humerus presenting 12 hours or more after injury.Methods: We reviewed the functional and radiological results of closed reduction and percutaneous pinning using crossed K-wires in 40 patients with displaced extension type supracondylar fracture of the humerus (Gartland type Ⅲ) with a delay of more than 12 hours in presentation. The average age of patients was 4.5 years and the mean delay in presentation was 17.55 hours.Results: Closed reduction and percutaneous pinning was successful in 90% of patients. The mean follow up period was 15 months. The Baumann's angle was restored within 4 degrees of the unaffected side in all patients. Use of a small medial incision in patients with severe swelling helped us avoid ulnar nerve injury. Using Flynn's criteria,38 patients (95%) had an excellent result. Two patients had mild myositis and both had a poor result. None of the patients developed cubitus varus.Conclusion: Closed reduction and crossed pinning of displaced supracondylar fractures of humerus in children is a safe and effective method even with delayed presentation.
文摘Objective: To explore chemical component changes of dog bone at different lengthening time and in different bone regions of interest, and to evaluate the mineralization during Ilizarov lengthening process. Methods: The ash weight, the concentrations of calcium, phosphorus and the calcium/phosphorus ratio were measured at different intervals (2, 4, 6, 8, 12 weeks) since lengthening and the lengthened part was compared with a control area at each interval. Results: The ash weight, the concentrations of calcium and phosphorus in the lengthened area differed at all development time. The calcium/phosphorus (Ca/P) ratio in the lengthened region remained significantly lower than that in the control region up to 12 weeks after the lengthening. Conclusions: These results suggest that also other inorganic ions play an important role in the mineralization process and that they become relatively more important since 8 weeks after the lengthening.
文摘We propose and study a predator prey model with state-dependent delay where the prey population is assumed to have an age structure. The state-dependent delay appears due to the mature condition that the prey must spend an amount of time in the immature stage sufficient to accumulate a threshold amount of food. We perform a qualitative analysis of the solutions, which includes studying positivity and boundedness, existence and local stability of equilibria. For the global dynamics of the system, we discuss an attracting region which is determined by solutions, and the region collapses to the interior equilibrium in the constant delay case.