Purinergic receptors are among the first cell surface receptors expressed during embryonic development (Burnstock and Ulrich, 2011). These are characterized based on their pharmacological properties of being activat...Purinergic receptors are among the first cell surface receptors expressed during embryonic development (Burnstock and Ulrich, 2011). These are characterized based on their pharmacological properties of being activated by adenosine or purine/pyrimidine nucleotides as P1 and P2 receptors. P2 receptors are further classified by their structure as P2Y metabotropic and P2X ionotropic receptors.展开更多
Objective: To investigate the changes of cyclin L2(CCNL2) gene mRNA and protein during the differentiation of P19 cells to cardiac myocytes, and to explore the relationship between CCNL2 gene and the differentiatio...Objective: To investigate the changes of cyclin L2(CCNL2) gene mRNA and protein during the differentiation of P19 cells to cardiac myocytes, and to explore the relationship between CCNL2 gene and the differentiation of cardiac myocytes. Methods: P19 cells were cultured with 0.9% DMSO for 18 days. Western blots of cardiac troponin I (cTnI) were used to identify cell differentiation. Total RNA was extracted from P19 cells during the process of differentiation at various time points:pre-differentiation(Day 0), and Day 1 to Day 18. The expression levels of CCNL2 gene mRNA and protein were evaluated by RT-PCR and Western blot, respectively. Results: After being induced to differentiate by DMSO for 4 days in suspension, spontaneously and rhythmically beating ceils were seen at 8 day, which were cTnI-positive. In P19 cells, both the expression level of CCNL2 gene mRNA and protein were gradually down-regulated. Conclusion: Both the expression of CCNL2 gene and protein were down-regulated during the process of the differentiation of P19 cells into cardiac myocytes, suggesting a possible role for this cyclin in their differentiation.展开更多
The Random Amplified Polymorphism DNA (RAPD) markers were used to stu dy the intra-specific diversity and regional differentiation of the Chinese fore st frogs (Rana chensinensis), which were sampled from the fields o...The Random Amplified Polymorphism DNA (RAPD) markers were used to stu dy the intra-specific diversity and regional differentiation of the Chinese fore st frogs (Rana chensinensis), which were sampled from the fields of 8 regions in Heilongjiang Province. Totally 78 polymorphic DNA loci were amplified by 10 RAP D primers. By genetic distance analysis and phylogenetic tree reconstruction wit h the Neighbor-Joining (NJ) method the results showed that the populations of Ch inese forest frogs distributed in 8 regions existed great differentiation (Avera ge Fst=0.347, SD=0.235) while there was the paradox between geographic distances and genetic distances. Based on geographic and geological data, a hypothesis wa s posed that it is very possible that the hilly lands in the downstream of the S onghua River and the Heilong River were the center of the origin of the Chinese forest frogs in Heilongjiang Province. And mainly through the Songhua River syst em, the Chinese forest frogs dispersed into the Songneng Plain from the Sanjiang Plain whereas the Fangzheng region became a sub-center for the western dispersi on.展开更多
The contents of earotenoids in the storage root of sweetpotato, Ipomoea batatas (L.) Lam. vary dramatically among different cultivars. However, so far little is known about the regulation of carotenoids synthesis in...The contents of earotenoids in the storage root of sweetpotato, Ipomoea batatas (L.) Lam. vary dramatically among different cultivars. However, so far little is known about the regulation of carotenoids synthesis in sweetpotato. In our laboratory, we identified a novel sweetpotato mutant, Nongdafu 14, which is a homogenous mutant derived from the wild type Kokei No. 14. The contents of carotenoids in the storage root of Nongdafu 14 were analyzed using high performance liquid chromatography (HPLC), and it was found that the amount of carotenoids, [3-carotene, lutein and zeaxantion, three major types of earotenoids in sweetpotato storage roots, increased 2-26 folds in Nongdafu 14 compared to Kokei No. 14. Suppression subtractive hybridization (SSH) was used to identify genes that were differentially expressed in Nongdafu 14, and a differentially expressed eDNA library was constructed using the eDNA of Nongdafu 14 storage roots as tester and that of Kokei No. 14 storage roots as driver. Out of the 1 530 clones sequenced, we identified 292 nonredundant ESTs. GO and KEGG analyses of these differentially expressed ESTs indicated that diverse metabolism pathways were affected and candidate genes involved in regulation of carotenoids synthesis are suggested.展开更多
To determine differential expression of genie male sterility A/B lines in Chinese cabbage-pak-choi (Brassica campestris ssp. chinensis Makino var. communis Tsen et Lee), we used the RNA fingerprinting technique, cDNA-...To determine differential expression of genie male sterility A/B lines in Chinese cabbage-pak-choi (Brassica campestris ssp. chinensis Makino var. communis Tsen et Lee), we used the RNA fingerprinting technique, cDNA-AFLP analysis, in different developmental stages and different tissues. While no obvious differential expressions were observed in rosette leaves, florescence leaves, and scapes, some differential expressions were found in alabstrums of A/B lines and among leaves, scapes and alabstrums. We analyzed the al-abstrums collected in different developmental stages with 10 primer combinations. We got a unique band between middle size alabstrums and large alabstrums in B line in one of the ten pair primers, and in another one pair, one band reflecting a higher gene-expression level in A line than that in B line was obtained. No unique bands were found with the other primer combinations. The bands reflecting different gene-expression level were confirmed by Northern hybridization. The results indicated that cDNA-AFLP was a suitable tool for studying differential expression of genie male sterility in plants. SDS-polyacrylamide gel electrophoresis patterns of soluble proteins further verified the difference in A/B lines.展开更多
Decomposition processes of the quenched Zn-Al alloys were studied by differential scanning calorimetry (DSC), X-ray diffraction (XRD) and transmission electron microscopy (TEM). The results show that the stabilities o...Decomposition processes of the quenched Zn-Al alloys were studied by differential scanning calorimetry (DSC), X-ray diffraction (XRD) and transmission electron microscopy (TEM). The results show that the stabilities of supersaturated solid solution (SSS) of Zn-Al alloy and α' phase formed by quenching would reduce with the increase of Zn content and the precipitation of η-Zn phases even when aging at ambient temperature, so that the exothermic precipitation peak in DSC curve would disappear. The activation energy of the η-Zn precipitation and the reaction enthalpy were calculated and measured. The kinetics of α' decomposition or η-Zn formation was determined by XRD. The microstructure change during aging was observed by TEM.展开更多
An x-ray scintillator screen with a special structure, functioning as detector and analyser grating, was proposed for collecting the interferogram of differential phase contrast imaging without absorption grating and ...An x-ray scintillator screen with a special structure, functioning as detector and analyser grating, was proposed for collecting the interferogram of differential phase contrast imaging without absorption grating and difficulty of fabrication by a state of the art technique. On the basis of phase grating diffraction, a detecting model of the scintillator screen was built for analysing the phase and absorption information of objects. According to the analysis, a new method of phase retrievals based on two-images and the optimal structure of screen were presented.展开更多
To evaluate the action of Apium graveolens L. on the growth and differentiation of neural stem cells (NSCs), cells culture and animal experiment were performed. NSCs were isolated from the striatum of SD rat embryo ...To evaluate the action of Apium graveolens L. on the growth and differentiation of neural stem cells (NSCs), cells culture and animal experiment were performed. NSCs were isolated from the striatum of SD rat embryo were cultured in the medium containing aqueous extract from Apium graveolens L(AAG).and/or the serum derived from mice treated with Apium graveolens L (SAG). The results show that AAG promoted the survival and growth of NSCs in low concentration. Apium graveolens L. leaves aqueous extract promoted the proliferation of NSCs in relatively high concentration. SAG significantly accelerated the differentiation of NSCs.展开更多
In order to screen the appropriate culture condition for the differentiation and regeneration of Prtmus avium L. adventitious buds, in this study, the effect of different hormone proportions on differentiation and reg...In order to screen the appropriate culture condition for the differentiation and regeneration of Prtmus avium L. adventitious buds, in this study, the effect of different hormone proportions on differentiation and regeneration of shoot tip explants were investigated using Gisela No. 5 and Gisela No. 6 as experimental materi- als. The results showed that, different hormone proportions had extremely significant effects ( P 〈0.01 ) on the differentiation rate of P. avium adventitious buds; the appropriate hormone proportions for Gisela No. 5 and Gisela No. 6 to induce dedifferentiation of adventitious buds were 6-BA 3.0 mg/L + IBA 0.5 mg/L + KT O. 1 mg/L and 6-BA 1.0 mg/L + IBA 0.5 mg/L + KT 0.2 rag/L, respectively. In addition, different hormone proportions had extremely significant effects (P 〈 0.01 ) on the regeneration coefficient and regeneration rate of P. avium adventitious buds; with the hormone proportion of 6-BA 1.0 mg/L + IBA 1.0 mg/L + KT 0.3mg/L, the number of regenerated adventitious buds reached the maximum for both varieties.展开更多
The upper earshoots with higher superiority usually have higher yield potential and higher efficiency.To determine the key period for the asynchronous differentiation of superior and inferior earshoots and how hormone...The upper earshoots with higher superiority usually have higher yield potential and higher efficiency.To determine the key period for the asynchronous differentiation of superior and inferior earshoots and how hormones are involved in this process,a two-year experiment was designed using two maize hybrids:Suyu 41(S41,single-ear hybrid)and AN 101(A101,double-ear hybrid).The results showed that the lag of lower earshoot differentiation was not only caused by the delay of the differentiation starting time but also related to extension of the duration in spikelet differentiation(stageⅡ)and sexual organ formation stage(stageⅣ).From 12 days before silking(DBS),the contents of indole-3-acetic acid(IAA),zeatin riboside(ZR)+zeatin(ZT),and gibberellic acid(GA_(3))in both upper and lower earshoots of the two hybrids increased dramatically and then decreased quickly.ABA slightly increased in the two hybrids and then decreased slowly in S41,while it was maintained at a high level in A101.At 8 DBS,i.e.,the transition period from floret differentiation to sexual organ formation stage,not only the growth of upper-to-lower earshoot difference(ULED),but also the values for ULED of IAA,ZR+ZT and GA_(3)were all significantly higher in S41 than in A101.Furthermore,the upper-to-lower hormone ratios IAA_(U)/AA_(L)and(ZR+ZT)_(U)/(ZR+ZT)_(L)were also much higher in the single-ear hybrid than in the double-ear hybrid,while the GA_(3U)/GA_(3L)and ABA_(U)/ABA_(L)had no significant differences.In addition,the time course of ULED_(hormone)/ULED_(earshoot growth rate)also suggested that the hormones work in different ways in earshoot superiority/inferiority formation.The delayed differentiation of lower ear shoots was conclusively related to the later initiation of differentiation and the longer durations of specific differentiation stages.Compared with the regulating roles of IAA and ZR+ZT in the key period(8 DBS)of superiority/inferiority differentiation,GA_(3) seems to be affected earlier,while ABA contributes little to this process.展开更多
In this paper the generalized nonlinear Euler differential equation t^2k(tu')u''+ t(f(u) + k(tu'))u' + g(u) = 0 is considered. Here the functions f(u), g(u) and k(u) satisfy smoothness conditio...In this paper the generalized nonlinear Euler differential equation t^2k(tu')u''+ t(f(u) + k(tu'))u' + g(u) = 0 is considered. Here the functions f(u), g(u) and k(u) satisfy smoothness conditions which guarantee the uniqueness of solutions of initial value problems, however, no conditions of sub(super) linearity are assumed. W'e present some necessary and sufficient conditions and some tests for the equivalent planar system to have or fail to have property (X^+), which is very important for the existence of periodic solutions and oscillation theory.展开更多
BACKGROUND: Alpha-actinin ( a -actinin) plays a key role in neuronal growth cone migration during directional differentiation from neural stem cells (NSCs) to neurons. OBJECTIVE: To detect in situ microdistribut...BACKGROUND: Alpha-actinin ( a -actinin) plays a key role in neuronal growth cone migration during directional differentiation from neural stem cells (NSCs) to neurons. OBJECTIVE: To detect in situ microdistribution and quantitative expression of a -actinin during directional differentiation of NSCs to neurons in the temporal lobe cerebral cortex of neonatal rats. DESIGN, TIME AND SETTING: Between January 2006 and December 2008, culture and directional differentiation of NSCs were performed at Department of Histology and Embryology, Preclinical Medical College, China Medical University. Immune electron microscopy was performed at Department of Histology and Embryology and Department of Electron Micrology, Preclinical Medical College, China Medical University. Spectrum analysis was performed at Laboratory of Electron Microscopy, Mental Research Institute, Chinese Academy of Sciences. MATERIALS: Basic fibroblast growth factor, epidermal growth factor, brain-derived nerve growth factor, type-1 insulin like growth factor, and a -actinin antibody were provided by Gibco BRL, USA; rabbit-anti-rat nestin monoclonal antibody, rabbit-anti-rat neuron specific enolase polyclonal antibody, and EDAX-9100 energy dispersive X-ray analysis were provided by PHILIPS Company, Netherlands. METHODS: NSCs, following primary and passage culture, were differentiated with serum culture medium (DMEM/F12 + 10% fetal bovine serum + 2 ng/mL brain-derived nerve growth factor + 2 ng/mL type-1 insulin like growth factor). MAIN OUTCOME MEASURES: Expression of a -actinin in neuron-like cells was quantitatively and qualitatively detected with immunocytochemistry using energy dispersive X-ray analysis. RESULTS: Immunocytochemistry, combined with electron microscopy, indicated that positive α -actinin expression was like a spheroid particle with high electron density. In addition, the expression was gradually concentrated from the nuclear edge to the cytoplasm and expanded into developing neurites, during differentiation of neural stem cells to neurons. Conversely, energy dispersive X-ray analysis indicated that the more mature the neural differentiation was, and the greater the expression of α -actinin. CONCLUSION: The gradual increase of α -actinin expression is related to growth, development, and maturity of differentiated neuron-like cells, in neonatal rat frontal lobe cortex, at different differentiating time points of NSCs to neurons.展开更多
Background: The plain abdominal x-ray is one of the commonly requested investigations in the children emergency room, paediatric surgical ward and neonatal wards. The short interval required to carry out this investig...Background: The plain abdominal x-ray is one of the commonly requested investigations in the children emergency room, paediatric surgical ward and neonatal wards. The short interval required to carry out this investigative procedure and obtain results makes it the first imaging modality used to unravel the different causes of acute abdominal conditions in children. The safety of abdominal x-ray in children makes it attractive for use in paediatric surgical practice as part of routine work-up for undifferentiated acute abdominal conditions and also to diagnose specific causes of acute abdomen in children. Setting: Olabisi Onabanjo University Teaching Hospital, Sagamu, Ogun State. Objectives: Evaluation of the role of plain abdominal x-ray in diagnosing common acute abdominal conditions in children. Materials and method: Patients admitted to the children emergency room, paediatric surgical wards, children’s ward and neonatal ward who had plain abdominal x-ray as part of their diagnostic work-up were included in the study. They were studied prospectively between March 2011 and April 2021. Results: Three Hundred and Ninety-nine patients who had plain abdominal x-rays as part of their diagnostic work-up were studied. Males were 240 while females were 159, a male to female ratio of 1.5:1. The patients were aged between 1 day to 16 years. Differential diagnoses made with plain abdominal x-ray were intestinal obstruction in 298, perforated viscus 69 patients, intra-abdominal masses 13 patients and location of intra-abdominal foreign body 14. Intestinal obstruction cases in which plain abdominal x-ray played a role in their diagnosis and management included the following: intussusception 66, neonatal sepsis 60, malrotation 48, intestinal atresia 42, anorectal malformation 32, hirschsprung’s disease in 30 cases, pyloric stenosis 24, obstructed hernia 22, post-operative adhesions 16 and intestinal helminthiasis 12. Perforated viscus accounted for 69 indications. Out of these indications, perforated gut in intussusception 19, perforated typhoid ileitis was responsible in 13 cases, gut perforation in blunt abdominal trauma 8, perforation in strangulated hernia 11 cases, perforated gut in malrotation 7, ceacal perforation in hirschsprugs disease 6 and colonic perforation in necrotizing enterocolitis 5 cases. Conclusion: Plain abdominal x-ray remains a role to play in the differential diagnosis and management of common paediatric acute abdominal conditions.展开更多
In this paper,the existence and uniqueness of iterative solutions to the boundary value problems for a class of first order impulsive integro-differential equations were studied. Under a new concept of upper and lower...In this paper,the existence and uniqueness of iterative solutions to the boundary value problems for a class of first order impulsive integro-differential equations were studied. Under a new concept of upper and lower solutions, a new monotone iterative technique on the boundary value problem of integro-differential equations was proposed. The existence and uniqueness of iterative solutions and the error estimation in certain interval were obtained.An example was also given to illustrate the results.展开更多
基金support from Fundacao de Amparo à Pesquisa do Estado de Sao Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)+2 种基金the Provost’s Office for Research of the University of Sao Paulo, Grant number: 2011.1.9333.1.3 (NAPNA-USP)support from the German Research Council (IL 20/182, RI 2092/1-2, IL 20/21-1)the Sino-German Centre for the Support of Science (GZ 919)
文摘Purinergic receptors are among the first cell surface receptors expressed during embryonic development (Burnstock and Ulrich, 2011). These are characterized based on their pharmacological properties of being activated by adenosine or purine/pyrimidine nucleotides as P1 and P2 receptors. P2 receptors are further classified by their structure as P2Y metabotropic and P2X ionotropic receptors.
文摘Objective: To investigate the changes of cyclin L2(CCNL2) gene mRNA and protein during the differentiation of P19 cells to cardiac myocytes, and to explore the relationship between CCNL2 gene and the differentiation of cardiac myocytes. Methods: P19 cells were cultured with 0.9% DMSO for 18 days. Western blots of cardiac troponin I (cTnI) were used to identify cell differentiation. Total RNA was extracted from P19 cells during the process of differentiation at various time points:pre-differentiation(Day 0), and Day 1 to Day 18. The expression levels of CCNL2 gene mRNA and protein were evaluated by RT-PCR and Western blot, respectively. Results: After being induced to differentiate by DMSO for 4 days in suspension, spontaneously and rhythmically beating ceils were seen at 8 day, which were cTnI-positive. In P19 cells, both the expression level of CCNL2 gene mRNA and protein were gradually down-regulated. Conclusion: Both the expression of CCNL2 gene and protein were down-regulated during the process of the differentiation of P19 cells into cardiac myocytes, suggesting a possible role for this cyclin in their differentiation.
基金the Natural Science Foundation of Heilongjiang Province (C9726).
文摘The Random Amplified Polymorphism DNA (RAPD) markers were used to stu dy the intra-specific diversity and regional differentiation of the Chinese fore st frogs (Rana chensinensis), which were sampled from the fields of 8 regions in Heilongjiang Province. Totally 78 polymorphic DNA loci were amplified by 10 RAP D primers. By genetic distance analysis and phylogenetic tree reconstruction wit h the Neighbor-Joining (NJ) method the results showed that the populations of Ch inese forest frogs distributed in 8 regions existed great differentiation (Avera ge Fst=0.347, SD=0.235) while there was the paradox between geographic distances and genetic distances. Based on geographic and geological data, a hypothesis wa s posed that it is very possible that the hilly lands in the downstream of the S onghua River and the Heilong River were the center of the origin of the Chinese forest frogs in Heilongjiang Province. And mainly through the Songhua River syst em, the Chinese forest frogs dispersed into the Songneng Plain from the Sanjiang Plain whereas the Fangzheng region became a sub-center for the western dispersi on.
基金supported by the China Agriculture Research System (CARS-11)the HarvestPlus Challenge Programthe National High-Tech Research and Development Project of China (2011AA100607)
文摘The contents of earotenoids in the storage root of sweetpotato, Ipomoea batatas (L.) Lam. vary dramatically among different cultivars. However, so far little is known about the regulation of carotenoids synthesis in sweetpotato. In our laboratory, we identified a novel sweetpotato mutant, Nongdafu 14, which is a homogenous mutant derived from the wild type Kokei No. 14. The contents of carotenoids in the storage root of Nongdafu 14 were analyzed using high performance liquid chromatography (HPLC), and it was found that the amount of carotenoids, [3-carotene, lutein and zeaxantion, three major types of earotenoids in sweetpotato storage roots, increased 2-26 folds in Nongdafu 14 compared to Kokei No. 14. Suppression subtractive hybridization (SSH) was used to identify genes that were differentially expressed in Nongdafu 14, and a differentially expressed eDNA library was constructed using the eDNA of Nongdafu 14 storage roots as tester and that of Kokei No. 14 storage roots as driver. Out of the 1 530 clones sequenced, we identified 292 nonredundant ESTs. GO and KEGG analyses of these differentially expressed ESTs indicated that diverse metabolism pathways were affected and candidate genes involved in regulation of carotenoids synthesis are suggested.
基金supported by the National Natural Science Foundation of China(39670512)
文摘To determine differential expression of genie male sterility A/B lines in Chinese cabbage-pak-choi (Brassica campestris ssp. chinensis Makino var. communis Tsen et Lee), we used the RNA fingerprinting technique, cDNA-AFLP analysis, in different developmental stages and different tissues. While no obvious differential expressions were observed in rosette leaves, florescence leaves, and scapes, some differential expressions were found in alabstrums of A/B lines and among leaves, scapes and alabstrums. We analyzed the al-abstrums collected in different developmental stages with 10 primer combinations. We got a unique band between middle size alabstrums and large alabstrums in B line in one of the ten pair primers, and in another one pair, one band reflecting a higher gene-expression level in A line than that in B line was obtained. No unique bands were found with the other primer combinations. The bands reflecting different gene-expression level were confirmed by Northern hybridization. The results indicated that cDNA-AFLP was a suitable tool for studying differential expression of genie male sterility in plants. SDS-polyacrylamide gel electrophoresis patterns of soluble proteins further verified the difference in A/B lines.
文摘Decomposition processes of the quenched Zn-Al alloys were studied by differential scanning calorimetry (DSC), X-ray diffraction (XRD) and transmission electron microscopy (TEM). The results show that the stabilities of supersaturated solid solution (SSS) of Zn-Al alloy and α' phase formed by quenching would reduce with the increase of Zn content and the precipitation of η-Zn phases even when aging at ambient temperature, so that the exothermic precipitation peak in DSC curve would disappear. The activation energy of the η-Zn precipitation and the reaction enthalpy were calculated and measured. The kinetics of α' decomposition or η-Zn formation was determined by XRD. The microstructure change during aging was observed by TEM.
基金supported by the National Natural Science Foundation of China (Grant Nos. 60232090 and 10774102)the Science & Technology Project from Shenzhen Government of China (Grant Nos. 2008340 and 200717)
文摘An x-ray scintillator screen with a special structure, functioning as detector and analyser grating, was proposed for collecting the interferogram of differential phase contrast imaging without absorption grating and difficulty of fabrication by a state of the art technique. On the basis of phase grating diffraction, a detecting model of the scintillator screen was built for analysing the phase and absorption information of objects. According to the analysis, a new method of phase retrievals based on two-images and the optimal structure of screen were presented.
文摘To evaluate the action of Apium graveolens L. on the growth and differentiation of neural stem cells (NSCs), cells culture and animal experiment were performed. NSCs were isolated from the striatum of SD rat embryo were cultured in the medium containing aqueous extract from Apium graveolens L(AAG).and/or the serum derived from mice treated with Apium graveolens L (SAG). The results show that AAG promoted the survival and growth of NSCs in low concentration. Apium graveolens L. leaves aqueous extract promoted the proliferation of NSCs in relatively high concentration. SAG significantly accelerated the differentiation of NSCs.
基金Supported by Special Fund for Key Laboratory of Shaanxi Provincial Scienceand Technology Department(2011HBSZS003)
文摘In order to screen the appropriate culture condition for the differentiation and regeneration of Prtmus avium L. adventitious buds, in this study, the effect of different hormone proportions on differentiation and regeneration of shoot tip explants were investigated using Gisela No. 5 and Gisela No. 6 as experimental materi- als. The results showed that, different hormone proportions had extremely significant effects ( P 〈0.01 ) on the differentiation rate of P. avium adventitious buds; the appropriate hormone proportions for Gisela No. 5 and Gisela No. 6 to induce dedifferentiation of adventitious buds were 6-BA 3.0 mg/L + IBA 0.5 mg/L + KT O. 1 mg/L and 6-BA 1.0 mg/L + IBA 0.5 mg/L + KT 0.2 rag/L, respectively. In addition, different hormone proportions had extremely significant effects (P 〈 0.01 ) on the regeneration coefficient and regeneration rate of P. avium adventitious buds; with the hormone proportion of 6-BA 1.0 mg/L + IBA 1.0 mg/L + KT 0.3mg/L, the number of regenerated adventitious buds reached the maximum for both varieties.
基金the National Key Research and Development Program of China(2016YFD0300109)。
文摘The upper earshoots with higher superiority usually have higher yield potential and higher efficiency.To determine the key period for the asynchronous differentiation of superior and inferior earshoots and how hormones are involved in this process,a two-year experiment was designed using two maize hybrids:Suyu 41(S41,single-ear hybrid)and AN 101(A101,double-ear hybrid).The results showed that the lag of lower earshoot differentiation was not only caused by the delay of the differentiation starting time but also related to extension of the duration in spikelet differentiation(stageⅡ)and sexual organ formation stage(stageⅣ).From 12 days before silking(DBS),the contents of indole-3-acetic acid(IAA),zeatin riboside(ZR)+zeatin(ZT),and gibberellic acid(GA_(3))in both upper and lower earshoots of the two hybrids increased dramatically and then decreased quickly.ABA slightly increased in the two hybrids and then decreased slowly in S41,while it was maintained at a high level in A101.At 8 DBS,i.e.,the transition period from floret differentiation to sexual organ formation stage,not only the growth of upper-to-lower earshoot difference(ULED),but also the values for ULED of IAA,ZR+ZT and GA_(3)were all significantly higher in S41 than in A101.Furthermore,the upper-to-lower hormone ratios IAA_(U)/AA_(L)and(ZR+ZT)_(U)/(ZR+ZT)_(L)were also much higher in the single-ear hybrid than in the double-ear hybrid,while the GA_(3U)/GA_(3L)and ABA_(U)/ABA_(L)had no significant differences.In addition,the time course of ULED_(hormone)/ULED_(earshoot growth rate)also suggested that the hormones work in different ways in earshoot superiority/inferiority formation.The delayed differentiation of lower ear shoots was conclusively related to the later initiation of differentiation and the longer durations of specific differentiation stages.Compared with the regulating roles of IAA and ZR+ZT in the key period(8 DBS)of superiority/inferiority differentiation,GA_(3) seems to be affected earlier,while ABA contributes little to this process.
文摘In this paper the generalized nonlinear Euler differential equation t^2k(tu')u''+ t(f(u) + k(tu'))u' + g(u) = 0 is considered. Here the functions f(u), g(u) and k(u) satisfy smoothness conditions which guarantee the uniqueness of solutions of initial value problems, however, no conditions of sub(super) linearity are assumed. W'e present some necessary and sufficient conditions and some tests for the equivalent planar system to have or fail to have property (X^+), which is very important for the existence of periodic solutions and oscillation theory.
基金Supported by:the National Natural Science Foundation of China,No.39970383the Project for Science and Technology from Educational Committee of Liaoning Province,No.202013132Technological Program for Colleges and Universities of Liaoning Educational Committee,No.[2008]84
文摘BACKGROUND: Alpha-actinin ( a -actinin) plays a key role in neuronal growth cone migration during directional differentiation from neural stem cells (NSCs) to neurons. OBJECTIVE: To detect in situ microdistribution and quantitative expression of a -actinin during directional differentiation of NSCs to neurons in the temporal lobe cerebral cortex of neonatal rats. DESIGN, TIME AND SETTING: Between January 2006 and December 2008, culture and directional differentiation of NSCs were performed at Department of Histology and Embryology, Preclinical Medical College, China Medical University. Immune electron microscopy was performed at Department of Histology and Embryology and Department of Electron Micrology, Preclinical Medical College, China Medical University. Spectrum analysis was performed at Laboratory of Electron Microscopy, Mental Research Institute, Chinese Academy of Sciences. MATERIALS: Basic fibroblast growth factor, epidermal growth factor, brain-derived nerve growth factor, type-1 insulin like growth factor, and a -actinin antibody were provided by Gibco BRL, USA; rabbit-anti-rat nestin monoclonal antibody, rabbit-anti-rat neuron specific enolase polyclonal antibody, and EDAX-9100 energy dispersive X-ray analysis were provided by PHILIPS Company, Netherlands. METHODS: NSCs, following primary and passage culture, were differentiated with serum culture medium (DMEM/F12 + 10% fetal bovine serum + 2 ng/mL brain-derived nerve growth factor + 2 ng/mL type-1 insulin like growth factor). MAIN OUTCOME MEASURES: Expression of a -actinin in neuron-like cells was quantitatively and qualitatively detected with immunocytochemistry using energy dispersive X-ray analysis. RESULTS: Immunocytochemistry, combined with electron microscopy, indicated that positive α -actinin expression was like a spheroid particle with high electron density. In addition, the expression was gradually concentrated from the nuclear edge to the cytoplasm and expanded into developing neurites, during differentiation of neural stem cells to neurons. Conversely, energy dispersive X-ray analysis indicated that the more mature the neural differentiation was, and the greater the expression of α -actinin. CONCLUSION: The gradual increase of α -actinin expression is related to growth, development, and maturity of differentiated neuron-like cells, in neonatal rat frontal lobe cortex, at different differentiating time points of NSCs to neurons.
文摘Background: The plain abdominal x-ray is one of the commonly requested investigations in the children emergency room, paediatric surgical ward and neonatal wards. The short interval required to carry out this investigative procedure and obtain results makes it the first imaging modality used to unravel the different causes of acute abdominal conditions in children. The safety of abdominal x-ray in children makes it attractive for use in paediatric surgical practice as part of routine work-up for undifferentiated acute abdominal conditions and also to diagnose specific causes of acute abdomen in children. Setting: Olabisi Onabanjo University Teaching Hospital, Sagamu, Ogun State. Objectives: Evaluation of the role of plain abdominal x-ray in diagnosing common acute abdominal conditions in children. Materials and method: Patients admitted to the children emergency room, paediatric surgical wards, children’s ward and neonatal ward who had plain abdominal x-ray as part of their diagnostic work-up were included in the study. They were studied prospectively between March 2011 and April 2021. Results: Three Hundred and Ninety-nine patients who had plain abdominal x-rays as part of their diagnostic work-up were studied. Males were 240 while females were 159, a male to female ratio of 1.5:1. The patients were aged between 1 day to 16 years. Differential diagnoses made with plain abdominal x-ray were intestinal obstruction in 298, perforated viscus 69 patients, intra-abdominal masses 13 patients and location of intra-abdominal foreign body 14. Intestinal obstruction cases in which plain abdominal x-ray played a role in their diagnosis and management included the following: intussusception 66, neonatal sepsis 60, malrotation 48, intestinal atresia 42, anorectal malformation 32, hirschsprung’s disease in 30 cases, pyloric stenosis 24, obstructed hernia 22, post-operative adhesions 16 and intestinal helminthiasis 12. Perforated viscus accounted for 69 indications. Out of these indications, perforated gut in intussusception 19, perforated typhoid ileitis was responsible in 13 cases, gut perforation in blunt abdominal trauma 8, perforation in strangulated hernia 11 cases, perforated gut in malrotation 7, ceacal perforation in hirschsprugs disease 6 and colonic perforation in necrotizing enterocolitis 5 cases. Conclusion: Plain abdominal x-ray remains a role to play in the differential diagnosis and management of common paediatric acute abdominal conditions.
基金National Natural Science Foundation of China(No.11271372)Hunan Provincial National Natural Science Foundation of China(No.12JJ2004)Central South University Graduate Innovation Project,China(No.2014zzts136)
文摘In this paper,the existence and uniqueness of iterative solutions to the boundary value problems for a class of first order impulsive integro-differential equations were studied. Under a new concept of upper and lower solutions, a new monotone iterative technique on the boundary value problem of integro-differential equations was proposed. The existence and uniqueness of iterative solutions and the error estimation in certain interval were obtained.An example was also given to illustrate the results.