LET R and R<sub>1</sub> be skew-fields with centres F and F<sub>1</sub>, where F F<sub>1</sub> and |F|】2. By M<sub>n</sub> （R）and I<sub>n</sub>（R） we de...LET R and R<sub>1</sub> be skew-fields with centres F and F<sub>1</sub>, where F F<sub>1</sub> and |F|】2. By M<sub>n</sub> （R）and I<sub>n</sub>（R） we denote the F-space of all n×n matrices over R and the set of all idempotentmatrices in M<sub>n</sub>（R）, respectively. If a linear map L from M<sub>n</sub>（R） to M<sub>m</sub>（R<sub>1</sub>） satisfies L（I<sub>n</sub>（R）） I<sub>m</sub>（R<sub>1</sub>） we call L an idempotence preserver （all such maps will be denoted byL<sub>n</sub>, m（R,R<sub>1</sub>））. To determine the forms of idempotence preservers is one important展开更多
This paper reports that the reaction of the propargyl bromides with aldehydes promoted by powdered lead in aqueous media. The selectivity and possible mechanism of these reactions are discussed. The yields of products...This paper reports that the reaction of the propargyl bromides with aldehydes promoted by powdered lead in aqueous media. The selectivity and possible mechanism of these reactions are discussed. The yields of products for reaction of propargyl bromide are 31 similar to 71%. The ratios of allenyl alcohol and homopropargyl alcohol are 1:1.5 to 1:3. The product for reaction of phenyl propargyl bromide is allenyl alcohol and the yields are 52 similar to 84%.展开更多
Background Acute myocardial infarction （AMI） is a common cause of heart failure （HF）, which can develop soon after AMI and may persist or resolve or develop late. HF after an MI is a major source of mortality. The...Background Acute myocardial infarction （AMI） is a common cause of heart failure （HF）, which can develop soon after AMI and may persist or resolve or develop late. HF after an MI is a major source of mortality. The cumulative incidence, prevalence and resolution of HF after MI in different age groups are poorly described. This study describes the natural history of HF after AMI according to age. Methods Patients with AMI during 1998 were identified from hospital records. HF was defined as treatment of symptoms and signs of HF with loop diuretics and was considered to have resolved if loop diuretic therapy could be stopped without recurrence of symptoms. Patients were cate- gorised into those aged 〈 65 years, 65-75 years, and 〉 75 years. Results Of 896 patients, 311,297 and 288 were aged 〈 65, 65-75 and 〉75 years and of whom 24%, 57% and 82% had died respectively by December 2005. Of these deaths, 24 （8%）, 68 （23%） and 107 （37%） oc- curred during the index admission, many associated with acute HF. A further 37 （12%）, 63 （21%） and 82 （29%） developed HF that persisted until discharge, of whom 15, 44 and 62 subsequently died. After discharge, 53 （24%）, 55 （40%） and 37 （47%） patients developed I-IF for the first time, of whom 26%, 62% and 76% subsequently died. Death was preceded by the development of HF in 35 （70%）, 93 （91%） and 107 （85%） in aged 〈 65 years, 65-75 years and 〉75 years, respectively. Conclusions The risk of developing HF and of dying after an MI in- creases progressively with age. Regardless of age, most deaths after a MI are preceded by the development of HF.展开更多
1 Geological settingThe King George Island is the largest one in South Shetland Islands, West Antarctica,with an area of 1200 km^2. Most of it is covered by ice and snow all the year round. It consistsmainly of Tertia...1 Geological settingThe King George Island is the largest one in South Shetland Islands, West Antarctica,with an area of 1200 km^2. Most of it is covered by ice and snow all the year round. It consistsmainly of Tertiary volcanics, associated with plutonic rocks and some late Mesozoic and Qua-展开更多
In this paper Comparative Molecular Field Analysis (CoMFA) method was applied to study the three-dimensional quantitative structure activity relationship (3D-QSAR) on a set of new herbicidal sulfonylureas. We optimize...In this paper Comparative Molecular Field Analysis (CoMFA) method was applied to study the three-dimensional quantitative structure activity relationship (3D-QSAR) on a set of new herbicidal sulfonylureas. We optimized molecular structures to improve their activities.展开更多
In facing the mounting clinical challenge and suboptimal techniques of craniofacial bone defects resulting from various conditions, such as congenital malformations, osteomyelitis, trauma and tumor resection, the ongo...In facing the mounting clinical challenge and suboptimal techniques of craniofacial bone defects resulting from various conditions, such as congenital malformations, osteomyelitis, trauma and tumor resection, the ongoing research of regenerative medicine using stem cells and concurrent advancement in biotechnology have shifted the focus from surgical reconstruction to a novel stem cell-based tissue engineering strategy for customized and functional craniofacial bone regeneration. Given the unique ontogenetical and cell biological properties of perinatal stem cells, emerging evidence has suggested these extraembryonic tissue-derived stem cells to be a promising cell source for extensive use in regenerative medicine and tissue engineering. In this review, we summarize the current achievements and obstacles in stem cell-based craniofacial bone regeneration and subsequently we address the characteristics of various types of perinatal stem cells and their novel application in tissue engineering of craniofacial bone. We propose the promising feasibility and scope of perinatal stem cell-based craniofacial bone tissue engineering for future clinical application.展开更多
文摘LET R and R<sub>1</sub> be skew-fields with centres F and F<sub>1</sub>, where F F<sub>1</sub> and |F|】2. By M<sub>n</sub> （R）and I<sub>n</sub>（R） we denote the F-space of all n×n matrices over R and the set of all idempotentmatrices in M<sub>n</sub>（R）, respectively. If a linear map L from M<sub>n</sub>（R） to M<sub>m</sub>（R<sub>1</sub>） satisfies L（I<sub>n</sub>（R）） I<sub>m</sub>（R<sub>1</sub>） we call L an idempotence preserver （all such maps will be denoted byL<sub>n</sub>, m（R,R<sub>1</sub>））. To determine the forms of idempotence preservers is one important
基金Supported by TTI Green genetics(TTI06201)Wageningen UR-Plant Breeding,C4C Holding,Sylvan,Dutch Product Board for Horticulture,the Greenery,Banken Mushrooms,We Be Engineering and National Basic Research Program of China(2014CB138305)
文摘This paper reports that the reaction of the propargyl bromides with aldehydes promoted by powdered lead in aqueous media. The selectivity and possible mechanism of these reactions are discussed. The yields of products for reaction of propargyl bromide are 31 similar to 71%. The ratios of allenyl alcohol and homopropargyl alcohol are 1:1.5 to 1:3. The product for reaction of phenyl propargyl bromide is allenyl alcohol and the yields are 52 similar to 84%.
文摘Background Acute myocardial infarction （AMI） is a common cause of heart failure （HF）, which can develop soon after AMI and may persist or resolve or develop late. HF after an MI is a major source of mortality. The cumulative incidence, prevalence and resolution of HF after MI in different age groups are poorly described. This study describes the natural history of HF after AMI according to age. Methods Patients with AMI during 1998 were identified from hospital records. HF was defined as treatment of symptoms and signs of HF with loop diuretics and was considered to have resolved if loop diuretic therapy could be stopped without recurrence of symptoms. Patients were cate- gorised into those aged 〈 65 years, 65-75 years, and 〉 75 years. Results Of 896 patients, 311,297 and 288 were aged 〈 65, 65-75 and 〉75 years and of whom 24%, 57% and 82% had died respectively by December 2005. Of these deaths, 24 （8%）, 68 （23%） and 107 （37%） oc- curred during the index admission, many associated with acute HF. A further 37 （12%）, 63 （21%） and 82 （29%） developed HF that persisted until discharge, of whom 15, 44 and 62 subsequently died. After discharge, 53 （24%）, 55 （40%） and 37 （47%） patients developed I-IF for the first time, of whom 26%, 62% and 76% subsequently died. Death was preceded by the development of HF in 35 （70%）, 93 （91%） and 107 （85%） in aged 〈 65 years, 65-75 years and 〉75 years, respectively. Conclusions The risk of developing HF and of dying after an MI in- creases progressively with age. Regardless of age, most deaths after a MI are preceded by the development of HF.
文摘1 Geological settingThe King George Island is the largest one in South Shetland Islands, West Antarctica,with an area of 1200 km^2. Most of it is covered by ice and snow all the year round. It consistsmainly of Tertiary volcanics, associated with plutonic rocks and some late Mesozoic and Qua-
文摘In this paper Comparative Molecular Field Analysis (CoMFA) method was applied to study the three-dimensional quantitative structure activity relationship (3D-QSAR) on a set of new herbicidal sulfonylureas. We optimized molecular structures to improve their activities.
基金National Natural Science Foundation of China,No.81271122 and No.81371122Shanghai Leading Academic Discipline Project,No.S30206
文摘In facing the mounting clinical challenge and suboptimal techniques of craniofacial bone defects resulting from various conditions, such as congenital malformations, osteomyelitis, trauma and tumor resection, the ongoing research of regenerative medicine using stem cells and concurrent advancement in biotechnology have shifted the focus from surgical reconstruction to a novel stem cell-based tissue engineering strategy for customized and functional craniofacial bone regeneration. Given the unique ontogenetical and cell biological properties of perinatal stem cells, emerging evidence has suggested these extraembryonic tissue-derived stem cells to be a promising cell source for extensive use in regenerative medicine and tissue engineering. In this review, we summarize the current achievements and obstacles in stem cell-based craniofacial bone regeneration and subsequently we address the characteristics of various types of perinatal stem cells and their novel application in tissue engineering of craniofacial bone. We propose the promising feasibility and scope of perinatal stem cell-based craniofacial bone tissue engineering for future clinical application.
