A new horned toad species,Boulenophrys elongata sp.nov.,is described from Mt.Lianhua,Huidong County,eastern Guangdong,China.The new species is phylogenetically closest to B.brachykolos,which is restricted to the east ...A new horned toad species,Boulenophrys elongata sp.nov.,is described from Mt.Lianhua,Huidong County,eastern Guangdong,China.The new species is phylogenetically closest to B.brachykolos,which is restricted to the east of the Pearl River Estuary(i.e.,Shenzhen City and Hong Kong SAR).The new species can be distinguished from all recognized congeners by a combination of morphological characters and genetic divergences in the combined mitochondrial 16S,12S and CO1 genes.We recommend the new species be listed as Data Deficient(DD)in the IUCN categorization,pending further investigation.展开更多
Ciliary neurotrophic factor is the only known neurotrophic factor that can promote differentiation of hippocampal neural progenitor cells to glial cells and neurons in adult rats. This process is similar to spontaneou...Ciliary neurotrophic factor is the only known neurotrophic factor that can promote differentiation of hippocampal neural progenitor cells to glial cells and neurons in adult rats. This process is similar to spontaneous differentiation. Therefore, ciliary neurotrophic factor may be involved in spontaneous differentiation of neural stem cells. To verify this hypothesis, the present study isolated neural progenitor cells from adult male rats and cultured them in vitro. Results showed that when neural progenitor cells were cultured in the absence of mitogen fibroblast growth factor-2 or epidermal growth factor, they underwent spontaneous differentiation into neurons and glial cells. Western blot and immunocytochemical staining showed that exogenous ciliary neurotrophic factor strongly induced adult hippocampal progenitor cells to differentiate into neurons and glial cells. Moreover, passage 4 adult hippocampal progenitor cells expressed high levels of endogenous ciliary neurotrophic factor, and a neutralizing antibody against ciliary neurotrophic factor prevented the spontaneous neuronal and glial differentiation of adult hippocampal progenitor cells. These results suggest that the spontaneous differentiation of adult hippocampal progenitor cells is mediated partially by endogenous ciliary neurotrophic factor.展开更多
We presented the solution of deformation-induced precipitation after homogenization to enhance the mechanical properties of Mg–6 Zn alloys.The results show that the improved strategy exhibits more effective strengthe...We presented the solution of deformation-induced precipitation after homogenization to enhance the mechanical properties of Mg–6 Zn alloys.The results show that the improved strategy exhibits more effective strengthening role than grain refinement methods based on low-temperature severe plastic deformation under the same strain.The low-temperature deformation with larger extrusion ratio results in massive nano-sized precipitates and excellent mechanical properties with the yield strength of 355 MPa and the ultimate tensile strength of 405 MPa.The increased mechanical properties are strong and tough enough to resist the stress and not be worn away when the alloy nail penetrates through the pig thigh bone,potentially extending more orthopedic surgery applications for Mg–Zn alloys.展开更多
BACKGROUND： Lentiviral vectors, a type of retroviral vector, are able to infect cells at all phases of cell cycle. They are able to express exogenous target genes in vivo over long periods of time with limited immuno...BACKGROUND： Lentiviral vectors, a type of retroviral vector, are able to infect cells at all phases of cell cycle. They are able to express exogenous target genes in vivo over long periods of time with limited immunological reaction. OBJECTIVE： To inhibit neuronal apoptosis by blocking the apoptotic cascade reaction, gene silencing of Caspase 3, and transfection of Caspase 3 short hairpin ribonucleic acid （shRNA） into Neuro 2a cells using a lentiviral vector.DESIGN： TiME-AND SETTING： An observational, genetic engineering cellular biology experiment was performed in Guangzhou Red Cross Hospital and Guangzhou Institute of Traumatic Surgery between March 2007 and June 2008. MATERIALS： PLL3.7, PCMV-VSV-G, and PH＇8.9∧PR plasmids were provided by the CBR Institute for Biomedical Research, Harvard Medical School, USA. Staurosporine was purchased from Sigma, USA.METHODS： Caspase 3 siRNA was synthesized and cloned into the PLL3.7 plasmid. The Caspase 3 shRNA-PLL3.7 Ientivirus was generated in 293T cells using a calcium phosphate transfection kit. After the lentivirus was transfected into Neuro 2a cells, apoptosis was induced in both the transfected and untransfected cells by staurosporine. Cell apoptosis was assessed by flow cvtometrv.MAIN OUTCOME MEASURES： Caspase 3 mRNA expression was measured by RT-PCR and Caspase protein expression was assessed by Western blot. Cellular apoptosis was determined by flow cytometry using Annevin V-PE/Taad-Cy7. RESULTS： The transfection rate of caspase 3 shRNA was 〉 98% using the lentiviral vector, RT-PCR and Western blot results demonstrated that significantly reduced Caspase 3 mRNA and protein expression in the transfected Neuro 2a. The control group exhibited 38.7% Annexin V/7aad-positive cells, which suggested apoptotic anaphase, while only 5.0% cells in the Caspase 3 gene silencing group entered apoptotic anaphase. CONCKUSION： Caspase 3 shRNA inhibited Caspase 3 expression in Neuro 2a ceils and decreased drug-induced apoptosis of Neuro 2a cells.展开更多
Query suggestions help users refine their queries after they input an initial query.Previous work on query suggestion has mainly concentrated on approaches that are similarity-based or context-based,developing models ...Query suggestions help users refine their queries after they input an initial query.Previous work on query suggestion has mainly concentrated on approaches that are similarity-based or context-based,developing models that either focus on adapting to a specific user(personalization)or on diversifying query aspects in order to maximize the probability of the user being satisfied(diversification).We consider the task of generating query suggestions that are both personalized and diversified.We propose a personalized query suggestion diversification(PQSD)model,where a user's long-term search behavior is injected into a basic greedy query suggestion diversification model that considers a user's search context in their current session.Query aspects are identified through clicked documents based on the open directory project(ODP)with a latent dirichlet allocation(LDA)topic model.We quantify the improvement of our proposed PQSD model against a state-of-the-art baseline using the public america online(AOL)query log and show that it beats the baseline in terms of metrics used in query suggestion ranking and diversification.The experimental results show that PQSD achieves its best performance when only queries with clicked documents are taken as search context rather than all queries,especially when more query suggestions are returned in the list.展开更多
基金supported by the Project of Background Survey of Biosafety in Guangdong Province(STST-2021-10)the Project of Study on Optimal Allocation and Sustainable Development of Typical Urban and Rural Ecological Resources(K610222062406).
文摘A new horned toad species,Boulenophrys elongata sp.nov.,is described from Mt.Lianhua,Huidong County,eastern Guangdong,China.The new species is phylogenetically closest to B.brachykolos,which is restricted to the east of the Pearl River Estuary(i.e.,Shenzhen City and Hong Kong SAR).The new species can be distinguished from all recognized congeners by a combination of morphological characters and genetic divergences in the combined mitochondrial 16S,12S and CO1 genes.We recommend the new species be listed as Data Deficient(DD)in the IUCN categorization,pending further investigation.
基金supported by the National Natural Science Foundation of China,No. 30770754
文摘Ciliary neurotrophic factor is the only known neurotrophic factor that can promote differentiation of hippocampal neural progenitor cells to glial cells and neurons in adult rats. This process is similar to spontaneous differentiation. Therefore, ciliary neurotrophic factor may be involved in spontaneous differentiation of neural stem cells. To verify this hypothesis, the present study isolated neural progenitor cells from adult male rats and cultured them in vitro. Results showed that when neural progenitor cells were cultured in the absence of mitogen fibroblast growth factor-2 or epidermal growth factor, they underwent spontaneous differentiation into neurons and glial cells. Western blot and immunocytochemical staining showed that exogenous ciliary neurotrophic factor strongly induced adult hippocampal progenitor cells to differentiate into neurons and glial cells. Moreover, passage 4 adult hippocampal progenitor cells expressed high levels of endogenous ciliary neurotrophic factor, and a neutralizing antibody against ciliary neurotrophic factor prevented the spontaneous neuronal and glial differentiation of adult hippocampal progenitor cells. These results suggest that the spontaneous differentiation of adult hippocampal progenitor cells is mediated partially by endogenous ciliary neurotrophic factor.
基金financially supported by the National Natural Science Foundation of China(No.51901068)。
文摘We presented the solution of deformation-induced precipitation after homogenization to enhance the mechanical properties of Mg–6 Zn alloys.The results show that the improved strategy exhibits more effective strengthening role than grain refinement methods based on low-temperature severe plastic deformation under the same strain.The low-temperature deformation with larger extrusion ratio results in massive nano-sized precipitates and excellent mechanical properties with the yield strength of 355 MPa and the ultimate tensile strength of 405 MPa.The increased mechanical properties are strong and tough enough to resist the stress and not be worn away when the alloy nail penetrates through the pig thigh bone,potentially extending more orthopedic surgery applications for Mg–Zn alloys.
基金Open Foundation of Key Laboratory of Biomedical Engineering,Guangdong Province,No.21030400Key Project of Guangzhou Medical and Health Care Foundation,No. 2006-ZDi-04
文摘BACKGROUND： Lentiviral vectors, a type of retroviral vector, are able to infect cells at all phases of cell cycle. They are able to express exogenous target genes in vivo over long periods of time with limited immunological reaction. OBJECTIVE： To inhibit neuronal apoptosis by blocking the apoptotic cascade reaction, gene silencing of Caspase 3, and transfection of Caspase 3 short hairpin ribonucleic acid （shRNA） into Neuro 2a cells using a lentiviral vector.DESIGN： TiME-AND SETTING： An observational, genetic engineering cellular biology experiment was performed in Guangzhou Red Cross Hospital and Guangzhou Institute of Traumatic Surgery between March 2007 and June 2008. MATERIALS： PLL3.7, PCMV-VSV-G, and PH＇8.9∧PR plasmids were provided by the CBR Institute for Biomedical Research, Harvard Medical School, USA. Staurosporine was purchased from Sigma, USA.METHODS： Caspase 3 siRNA was synthesized and cloned into the PLL3.7 plasmid. The Caspase 3 shRNA-PLL3.7 Ientivirus was generated in 293T cells using a calcium phosphate transfection kit. After the lentivirus was transfected into Neuro 2a cells, apoptosis was induced in both the transfected and untransfected cells by staurosporine. Cell apoptosis was assessed by flow cvtometrv.MAIN OUTCOME MEASURES： Caspase 3 mRNA expression was measured by RT-PCR and Caspase protein expression was assessed by Western blot. Cellular apoptosis was determined by flow cytometry using Annevin V-PE/Taad-Cy7. RESULTS： The transfection rate of caspase 3 shRNA was 〉 98% using the lentiviral vector, RT-PCR and Western blot results demonstrated that significantly reduced Caspase 3 mRNA and protein expression in the transfected Neuro 2a. The control group exhibited 38.7% Annexin V/7aad-positive cells, which suggested apoptotic anaphase, while only 5.0% cells in the Caspase 3 gene silencing group entered apoptotic anaphase. CONCKUSION： Caspase 3 shRNA inhibited Caspase 3 expression in Neuro 2a ceils and decreased drug-induced apoptosis of Neuro 2a cells.
基金supported by the National Natural Science Foundation of China(Grant No.61702526)the National Advanced Research Project(6141B0801010b)。
文摘Query suggestions help users refine their queries after they input an initial query.Previous work on query suggestion has mainly concentrated on approaches that are similarity-based or context-based,developing models that either focus on adapting to a specific user(personalization)or on diversifying query aspects in order to maximize the probability of the user being satisfied(diversification).We consider the task of generating query suggestions that are both personalized and diversified.We propose a personalized query suggestion diversification(PQSD)model,where a user's long-term search behavior is injected into a basic greedy query suggestion diversification model that considers a user's search context in their current session.Query aspects are identified through clicked documents based on the open directory project(ODP)with a latent dirichlet allocation(LDA)topic model.We quantify the improvement of our proposed PQSD model against a state-of-the-art baseline using the public america online(AOL)query log and show that it beats the baseline in terms of metrics used in query suggestion ranking and diversification.The experimental results show that PQSD achieves its best performance when only queries with clicked documents are taken as search context rather than all queries,especially when more query suggestions are returned in the list.
