There is a major transformation in gene expression between mature B cells （including follicular, marginal zone, and germinal center cells） and antibody secreting cells （ASCs）, i.e. , ASCs, （including plasma blas...There is a major transformation in gene expression between mature B cells （including follicular, marginal zone, and germinal center cells） and antibody secreting cells （ASCs）, i.e. , ASCs, （including plasma blasts, splenic plasma cells, and long-lived bone marrow plasma cells）. This signifcant change-over occurs to accommodate the massive amount of secretory-specific immunoglobulin that ASCs make and the export processes itself. It is well known that there is an up-regulation of a small number of ASC-specific transcription factors Prdm1 （B-lymphocyte-induced maturation protein 1）, interferon regulatory factor 4, and Xbp1, and the reciprocal down-regulation of Pax5, Bcl6 and Bach2, which maintain the B cell program. Less well appreciated are the major alterations in transcription elongation and RNA proce-ssing occurring between B cells and ASCs. The three ELL family members ELL1, 2 and 3 have different protein sequences and potentially distinct cellular roles in transcription elongation. ELL1 is involved in DNA repair and small RNAs while ELL3 was previously described as either testis or stem-cell specifc. After B cell stimulation to ASCs, ELL3 levels fall precipitously while ELL1 falls off slightly. ELL2 is induced at least 10-fold in ASCs relative to B cells. All of these changes cause the RNA Polymerase Ⅱ in ASCs to acquire different properties, leading to differences in RNA processing and histone modifcations.展开更多
Objective: To investigate the role of human theca cell(TC) and granulo sa cell(GC) interaction and insulin(INS) in steroidogenesis in normal ovarian cy cle and in patients with PCOS. Methods: Ovarian theca and granulo...Objective: To investigate the role of human theca cell(TC) and granulo sa cell(GC) interaction and insulin(INS) in steroidogenesis in normal ovarian cy cle and in patients with PCOS. Methods: Ovarian theca and granulosa cells from eleven normal wo men and eight PCOS patients were co-cultured on opposite side of collagen with or without INS. The concentrations of estradiol(E2), progesterone(P) and andro stenedione (A) in the culture medium were examined by ELISA method.Results: When co-cultured with GC, TC in PCOS group produced mo re A and less P than those of normal group. When co-cultured with theca cells, granulosa cells in PCOS group produced more E2 than those of normal group. Add ition of INS increased the difference significantly.Conclusions: The GC and TC interaction from the normal and PCOS ovaries is different. There is a high A and high E2 intraovary loop of PC OS leading to premature arrest of follicle growth and anovulation. Insulin may p lay an important regulatory role.展开更多
A fragment of 2000 bp upstream sequence of Ell clone was amplified from genomic DNA of the tomato cultivar Zhongshu- 5. Sequence analysis showed that the upstream contains the regulatory elements： TATA box （-29 - -2...A fragment of 2000 bp upstream sequence of Ell clone was amplified from genomic DNA of the tomato cultivar Zhongshu- 5. Sequence analysis showed that the upstream contains the regulatory elements： TATA box （-29 - -22）, CAAT box （-193 - -189）, wound, and drought response elements. Expression vectors of Ell promoter gus fusion were constructed with the promoters of 1 200 and 2 000 bp regions, respectively. Transgenic tomato plants were obtained through Agrobacteriummediated transformation. Histochemical analysis of GUS activity in various tissues showed that the two promoters were able to direct fruit-specific gene expression. The expression driven by promoter of 2 000 bp upstream fragment could increase GUS activity with the maturation of tomato fruits. The promoter of -1 200 bp fragment could direct gus gene expression in fruits with the inductions of drought and wounding. The regulatory region for fruit-specificity was probably located in the region of 1 200 bp of 5′-flanking sequence and some positive regulatory elements or enhancers may exist in the region from -1 200 to -2000 bp.展开更多
Linearized equations of fluid dynamics of cell two phase flow for one dimensional case are proposed. Based on the equations, an analytic solution is derived, in which the frequency of wave is observed. The frequency f...Linearized equations of fluid dynamics of cell two phase flow for one dimensional case are proposed. Based on the equations, an analytic solution is derived, in which the frequency of wave is observed. The frequency formula consists of all important parameters of the fluid dynamics. In our observation, the group velocity and phase velocity of the motion of wave propagation are explicitly exhibited as well.展开更多
In this paper, we investigate the self-propelled particles confined on a spherical substrate and explore the structural and dynamic properties of self-propelled particles by controlling the packing fraction and activi...In this paper, we investigate the self-propelled particles confined on a spherical substrate and explore the structural and dynamic properties of self-propelled particles by controlling the packing fraction and activity. We find that these self-propelled particles freeze into the crystal with the increase in the packing fraction. We observe the pattern evolution of inevitable topological defects due to the geometric constraints of the spherical substrate. During the process of freezing, there is a transition from twelve isolated grain boundaries to the uniform distribution of defects with the increase in the self-propelled velocity. Finally, we establish a phase diagram of the freezing process. These results may deepen our understanding of active particles in complex and crowded environments.展开更多
Influence of temperature on effective value of a current density of a semiconductor solar cell is investigated. New equations for explanation of dependence of photovoltaic characteristics of solar cell from temperatur...Influence of temperature on effective value of a current density of a semiconductor solar cell is investigated. New equations for explanation of dependence of photovoltaic characteristics of solar cell from temperature are received.展开更多
Constructivism is a psychological theory of knowledge which argues that humans construct knowledge and meaning from their experiences. The learner-centered approach is advocated by constructivism. And constructivism e...Constructivism is a psychological theory of knowledge which argues that humans construct knowledge and meaning from their experiences. The learner-centered approach is advocated by constructivism. And constructivism emphasizes the importance of the learner being actively involved in the learning process. Thus teacher＇s task has changed to construct and arrange learning environment. In this environment, student is planner, monitor and also evaluator; while teacher acts as administrator, organizer, catalyst, facilitator, consultant, diagnostician, guide, and model of learning instead of the source of knowledge, the disseminator of knowledge and the implanter in the learning process. As for ELL of the tertiary-level students, teachers should have some new teaching methods with the instruction of constructivism, such as transmitting knowledge, exposing learners to tasks, creating a supportive learning environment, etc.展开更多
基金Supported by The National Science Foundation grant MCB-08-42725National Institutes of Health shared resources Grant No.P30CA047904 to the University of Pittsburgh Cancer Instituteinternal funding from the School of Medicine and Department of Immunology
文摘There is a major transformation in gene expression between mature B cells （including follicular, marginal zone, and germinal center cells） and antibody secreting cells （ASCs）, i.e. , ASCs, （including plasma blasts, splenic plasma cells, and long-lived bone marrow plasma cells）. This signifcant change-over occurs to accommodate the massive amount of secretory-specific immunoglobulin that ASCs make and the export processes itself. It is well known that there is an up-regulation of a small number of ASC-specific transcription factors Prdm1 （B-lymphocyte-induced maturation protein 1）, interferon regulatory factor 4, and Xbp1, and the reciprocal down-regulation of Pax5, Bcl6 and Bach2, which maintain the B cell program. Less well appreciated are the major alterations in transcription elongation and RNA proce-ssing occurring between B cells and ASCs. The three ELL family members ELL1, 2 and 3 have different protein sequences and potentially distinct cellular roles in transcription elongation. ELL1 is involved in DNA repair and small RNAs while ELL3 was previously described as either testis or stem-cell specifc. After B cell stimulation to ASCs, ELL3 levels fall precipitously while ELL1 falls off slightly. ELL2 is induced at least 10-fold in ASCs relative to B cells. All of these changes cause the RNA Polymerase Ⅱ in ASCs to acquire different properties, leading to differences in RNA processing and histone modifcations.
文摘Objective: To investigate the role of human theca cell(TC) and granulo sa cell(GC) interaction and insulin(INS) in steroidogenesis in normal ovarian cy cle and in patients with PCOS. Methods: Ovarian theca and granulosa cells from eleven normal wo men and eight PCOS patients were co-cultured on opposite side of collagen with or without INS. The concentrations of estradiol(E2), progesterone(P) and andro stenedione (A) in the culture medium were examined by ELISA method.Results: When co-cultured with GC, TC in PCOS group produced mo re A and less P than those of normal group. When co-cultured with theca cells, granulosa cells in PCOS group produced more E2 than those of normal group. Add ition of INS increased the difference significantly.Conclusions: The GC and TC interaction from the normal and PCOS ovaries is different. There is a high A and high E2 intraovary loop of PC OS leading to premature arrest of follicle growth and anovulation. Insulin may p lay an important regulatory role.
基金This research work was partially supported by the National Natural Science Foundation of China(39770521,39200079)National 863 Program of China(2001AA212221).
文摘A fragment of 2000 bp upstream sequence of Ell clone was amplified from genomic DNA of the tomato cultivar Zhongshu- 5. Sequence analysis showed that the upstream contains the regulatory elements： TATA box （-29 - -22）, CAAT box （-193 - -189）, wound, and drought response elements. Expression vectors of Ell promoter gus fusion were constructed with the promoters of 1 200 and 2 000 bp regions, respectively. Transgenic tomato plants were obtained through Agrobacteriummediated transformation. Histochemical analysis of GUS activity in various tissues showed that the two promoters were able to direct fruit-specific gene expression. The expression driven by promoter of 2 000 bp upstream fragment could increase GUS activity with the maturation of tomato fruits. The promoter of -1 200 bp fragment could direct gus gene expression in fruits with the inductions of drought and wounding. The regulatory region for fruit-specificity was probably located in the region of 1 200 bp of 5′-flanking sequence and some positive regulatory elements or enhancers may exist in the region from -1 200 to -2000 bp.
基金Supported by the National Natural Science Foundation of China(10672022)
文摘Linearized equations of fluid dynamics of cell two phase flow for one dimensional case are proposed. Based on the equations, an analytic solution is derived, in which the frequency of wave is observed. The frequency formula consists of all important parameters of the fluid dynamics. In our observation, the group velocity and phase velocity of the motion of wave propagation are explicitly exhibited as well.
基金Project supported by the National Natural Science Foundation of China(Nos.11622222,11472271,and 11872357)the Thousand Young Talents Program of China+1 种基金the Fundamental Research Fund for the Central Universitiesthe Strategic Priority Research Program of Chinese Academy of Sciences(No.XDB22040403)
文摘In this paper, we investigate the self-propelled particles confined on a spherical substrate and explore the structural and dynamic properties of self-propelled particles by controlling the packing fraction and activity. We find that these self-propelled particles freeze into the crystal with the increase in the packing fraction. We observe the pattern evolution of inevitable topological defects due to the geometric constraints of the spherical substrate. During the process of freezing, there is a transition from twelve isolated grain boundaries to the uniform distribution of defects with the increase in the self-propelled velocity. Finally, we establish a phase diagram of the freezing process. These results may deepen our understanding of active particles in complex and crowded environments.
文摘Influence of temperature on effective value of a current density of a semiconductor solar cell is investigated. New equations for explanation of dependence of photovoltaic characteristics of solar cell from temperature are received.
文摘Constructivism is a psychological theory of knowledge which argues that humans construct knowledge and meaning from their experiences. The learner-centered approach is advocated by constructivism. And constructivism emphasizes the importance of the learner being actively involved in the learning process. Thus teacher＇s task has changed to construct and arrange learning environment. In this environment, student is planner, monitor and also evaluator; while teacher acts as administrator, organizer, catalyst, facilitator, consultant, diagnostician, guide, and model of learning instead of the source of knowledge, the disseminator of knowledge and the implanter in the learning process. As for ELL of the tertiary-level students, teachers should have some new teaching methods with the instruction of constructivism, such as transmitting knowledge, exposing learners to tasks, creating a supportive learning environment, etc.
