OBJECTIVE It′s known that post-retrieval extinction but not extinction alone could erase fear memory. However, whether the coding pattern of original fear engrams is remodeled or inhibited remains largely unclear. He...OBJECTIVE It′s known that post-retrieval extinction but not extinction alone could erase fear memory. However, whether the coding pattern of original fear engrams is remodeled or inhibited remains largely unclear. Here we try to investigate whether the coding pattern of memory engrams is altered during post-retrieval extinction induced memory updating. METHODS To answer the question, by using activity-dependent neuronal-tagging technology, neuronal tracing technique combined with optogenetic manipulation and in vivo calcium imaging, we identified the fear and extinction cells in PrL and BLA and investigated the dynamic encoding of memory engram ensembles in the PrL and BLA during CS versus US initiated memory updating.RESULTS We found increased reactivation of engram cells in the prelimbic cortex and basolateral amygdala during memory updating. Moreover, conditioned stimulus and unconditioned stimulu sinitiated memory updating depend on the engram cells reactivation in the prelimbic cortex or basolateral amygdala respectively. Finally,we found memory updating causes increased overlapping between fear and extinction cells and the original fear engrams encoding was altered during memory updating. CONCLUSION Our data provide the first evidence to show the overlapping ensembles between fear and extinction cells and functional reorganization of original engrams underlying conditioned stimulus and unconditioned stimulus initiated memory updating.展开更多
Cas1-and-Cas2-mediated new spacer acquisition is an essential process for bacterial adaptive immunity.The process is critical for the ecology of the oral microflora and oral health.Although molecular mechanisms for sp...Cas1-and-Cas2-mediated new spacer acquisition is an essential process for bacterial adaptive immunity.The process is critical for the ecology of the oral microflora and oral health.Although molecular mechanisms for spacer acquisition are known,it has never been established if this process is associated with the morphological changes of bacteria.In this study,we demonstrated a novel Cas2-induced filamentation phenotype in E.coli that was regulated by co-expression of the Cas1 protein.A 30 amino acid motif at the carboxyl terminus of Cas2 is necessary for this function.By imaging analysis,we provided evidence to argue that Cas-induced filamentation is a step coupled with new spacer acquisition during which filaments are characterised by polyploidy with asymmetric cell division.This work may open new opportunities to investigate the adaptive immune response and microbial balance for oral health.展开更多
A novel atmospheric plasma device developed in this paper, which is more effective and convenient to study the plasma-initiated polymerization (PIP) than conventional setup. The structure and mechanism of the device i...A novel atmospheric plasma device developed in this paper, which is more effective and convenient to study the plasma-initiated polymerization (PIP) than conventional setup. The structure and mechanism of the device is introduced. Some plasma-initiated polymerization experiments are carried out on the device, and the conversion of AA (Acrylic acid) and AM (Acryl amide) atmospheric (N2) plasma polymerization are respectively 89% and 94% after 120 h post polymerization, whereby IR spectra of the product (AA, AM). Our PIP result are confirmed.展开更多
The polymerization of methyl acrylate was sensitive to UV light. Under UV light,the rate of polymerization is 8 times as high as the rate in dark.The overall activation energy was decreased by the UV light (313nm).A t...The polymerization of methyl acrylate was sensitive to UV light. Under UV light,the rate of polymerization is 8 times as high as the rate in dark.The overall activation energy was decreased by the UV light (313nm).A tentative explanation is given and the mechanism is discussed.展开更多
Plasma initiated polymerization is a kind of well-known radical polymerization mechanism, but it has the ＇living＇ polymerization feature and produces ultra-high molecular weight polymer. In order to explain such phe...Plasma initiated polymerization is a kind of well-known radical polymerization mechanism, but it has the ＇living＇ polymerization feature and produces ultra-high molecular weight polymer. In order to explain such phenomena, we calculate the basic data of plasma initiated polymerization of methylmethacrylate （MMA） according to the principle of polymer physics and chemistry. It results in that the radical concentration ranges from 10^-12mol/L to 10^-16mol/L corresponding to the radical life in 10^4s to 10^8s, which means the radicals have a long lifetime. Moreover because of the long lifetime radicals it causes a unique feature rather than the common radical polymerization, and also shows no ＂living polymerization＂. It is noticed in experiments that there are two key factors playing important roles. One is the effective radical amount produced during the plasma discharging while the another is the diffusion factor.展开更多
he volatile (VPP) and nonvolatile (NVPP) products of methyl methacrylate(MMA) reaction in plasma chamber were used as initiators of MMA polymeriza-tion. From the structure analyses of the two initiators, the measureme...he volatile (VPP) and nonvolatile (NVPP) products of methyl methacrylate(MMA) reaction in plasma chamber were used as initiators of MMA polymeriza-tion. From the structure analyses of the two initiators, the measurement of poly-merization kinetics, and the determination of the molecular weight of resultantpolymers , we found tliat MMA polymerization initiated by NVPP is a typical radical mechanism of polymerization which undergoes a process of continuous initiationand bifunction termination , while VPP-initiated polymerization suggested a mech-anism of living radical process fpolymerization with instantaneous initiation , chain-transfer to monomer , without termination).展开更多
The integrity of the published record of scientific research depends not only on the validity of the science but also on honesty in authorship. Editors and readers need to be confident that authors have undertaken the...The integrity of the published record of scientific research depends not only on the validity of the science but also on honesty in authorship. Editors and readers need to be confident that authors have undertaken the work described and have ensured that the manuscript accurately reflects their work, irrespective of whether they took the lead in writing or sought assistance from a medical writer. The scientific record is distorted if the primary purpose of an article is to persuade readers in favor of a special interest, rather than to inform and educate, and this purpose is concealed.展开更多
The homopolymerization of 5-methyl-5-hexen-2,4-dione (methacryloylacetone, MAA), a vinyl monomer having beta-diketone group, was carried out in the presence of benzophenone (BP)/N, N-dimenthyl-4-toluidine (DMT) system...The homopolymerization of 5-methyl-5-hexen-2,4-dione (methacryloylacetone, MAA), a vinyl monomer having beta-diketone group, was carried out in the presence of benzophenone (BP)/N, N-dimenthyl-4-toluidine (DMT) system. Graft polymerization of acrylamide initiated by eerie ion onto the homopolymer film was investigated and the mechanism of the grafting reaction was proposed on the basis of ESR study. The grafted copolymer was characterized by means of grafting percentage, water absorption, XPS spectra and scanning electron photomicrographs.展开更多
The polymerization of acrylamide and acrylonitrile using ceric ion as initiator can be promoted greatly by the tartaric acid. The kinetics of acrylamide polymerization initiated by ceric ion/tartaric acid has been stu...The polymerization of acrylamide and acrylonitrile using ceric ion as initiator can be promoted greatly by the tartaric acid. The kinetics of acrylamide polymerization initiated by ceric ion/tartaric acid has been studied. The presence of the species of tartaric acid in Polyacrylonitrile produced by using ceric ion/tartaric acid as niitiator has been confirmed by FT-IR analysis.展开更多
<strong>Introduction:</strong> Viral hepatitis is a major public health challenge that requires an urgent response. Reducing mortality requires major scale-up in prevention, testing and treatment access;co...<strong>Introduction:</strong> Viral hepatitis is a major public health challenge that requires an urgent response. Reducing mortality requires major scale-up in prevention, testing and treatment access;coverage in HBV vaccination, testing and treatment is low and must accelerate massively to achieve the 2030 targets. Less than 1% of HBV-infected individuals are diagnosed in Sub-Sahara Africa, despite the availability of rapid tests with good diagnostic accuracy. <strong>Materials and Methods:</strong> This was retrospective cross sectional study conducted in Federal Teaching Hospital Gombe, in North East Nigeria. All children and adults who presented to the out-patient departments, and those that were admitted irrespective of their HIV and or Hepatitis C virus status and had Hepatitis B and/or Hepatitis B envelope antigen test were conducted between 2000 to 2015. All children and adults were tested using the Hospital standard for Hepatitis B surface antigen test strip. <strong>Results:</strong> Between 2000 and 2014, 739,456 children and adults were admitted and reviewed in the outpatient units of the Federal Teaching Hospital Gombe;there were 685,552 adults and 53,904 children. Children constituted 7.3% (53,904/739,456) of admissions and outpatient consultations. 2.8% (210/7570), 3.3% (773/23,783), 3.6% (1145/32,142), 5.2% (1694/33,043), 3.3% (986/29,216), 1.9% (661/3321), 0.1% (53/41,626), 0.2% (113/46,634), 2.6% (1418/54,423), 5.4% (3717/69,696), 3.7% (2332/62,086), 3.5% (3241/90,623), 3.2% (2881/89,398), 3.8% (2428/62,687), 2.8% (1835/63,208) of children and adults were tested for HBsAg in 2000, 2001, 20002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011, 2012, 2013 and 2014 respectively. 23,487 children and adults were tested for HBsAg with a cumulative testing rate of 3%. Overall 4465/23,487 children and adults were seropositive for HBsAg giving a cumulative prevalence of 19%. <strong>Conclusion:</strong> HBV screening in our health facility is very low. Massive scale up in awareness and HBV vaccination are required. Provider initiated testing and counseling for HBV in health facilities needs support for implementation in Health Facilities in Sub Saharan Africa.展开更多
perfluoroalkyl iodides reacted with alkenes in acetonitrile solu- tion containing catalytic amount of organophosphine under mild condition to give the corresponding adducts in moderate to good yields.Reaction was show...perfluoroalkyl iodides reacted with alkenes in acetonitrile solu- tion containing catalytic amount of organophosphine under mild condition to give the corresponding adducts in moderate to good yields.Reaction was shown to involve a free radical mechanism.展开更多
On May 20, 2006, General Administration of Quality Sup ervision,Inspection and Quarantine of the P.R.China conducted startup ceremony of "Initiating Resources Conservation Service" to coordinate the acti... On May 20, 2006, General Administration of Quality Sup ervision,Inspection and Quarantine of the P.R.China conducted startup ceremony of "Initiating Resources Conservation Service" to coordinate the activities of propaganda for the seventh World Metrology Day.……展开更多
Currently, the application work on 2008 Product Development Contribution Award of China National Textile &Apparel Council, has been initiated, and this award is established
Major progress has been achieved in the development of the prototype of FY-4 meteorological satellite.After two years development,the FY-4 development team with SAST as the leader finished the electrical model of the ...Major progress has been achieved in the development of the prototype of FY-4 meteorological satellite.After two years development,the FY-4 development team with SAST as the leader finished the electrical model of the satellite and passed the preliminary design review.The development of the prototype validation satellite has been initiated.FY-4 will be China's first geostationary Earth observation remote展开更多
A program of ex situ conservation initiated by the CAS to protect the national indigenous flora was revealed recently by a group of CAS scientists in a letter to the prestigious journal 'Science'.……
The ring-opening polymerization of D, L-lactide in the melt was systematically investigated by using stannous octoate as the initiator. The molecular weight of poly (D, L-lactide) was characterized with M,. Mn and Mw ...The ring-opening polymerization of D, L-lactide in the melt was systematically investigated by using stannous octoate as the initiator. The molecular weight of poly (D, L-lactide) was characterized with M,. Mn and Mw respectively. The results indicated that five variables, namely purity of monomer, initiator to monomer ratio, vacuum level, polymerization temperature and polymerization time had different influences on the molecular weight and molecular weight distribution of poly(D. L-lactide).展开更多
Acrylamide polymerization initiated with a redox initiation system consisting of eerie ion and ethyl N,N-diethyldithiocarbamyl acetate (EDCA) has been studied. It was found that the polymerization rate equation is in ...Acrylamide polymerization initiated with a redox initiation system consisting of eerie ion and ethyl N,N-diethyldithiocarbamyl acetate (EDCA) has been studied. It was found that the polymerization rate equation is in good agreement with that of a redox initiated polymerization, and the overall activation energy of the polymerization was determined to be 25.2 kJ.mol(-1). Accordingly, the system belongs to a redox initiator. The initiation mechanism was proposed based on the end group analysis using FT-IR, UV spectroscopies. Analysis results revealed that the N, N-diethyldithiocarbamyl radical produced from the redox reaction of EDCA with eerie ion can initiate acrylonitrile (AN) polymerization and form the end group on PAN. The resulting PAN was photopolymerized with butyl acrylate (BE) to form PAN-b-PBA block copolymer.展开更多
文摘OBJECTIVE It′s known that post-retrieval extinction but not extinction alone could erase fear memory. However, whether the coding pattern of original fear engrams is remodeled or inhibited remains largely unclear. Here we try to investigate whether the coding pattern of memory engrams is altered during post-retrieval extinction induced memory updating. METHODS To answer the question, by using activity-dependent neuronal-tagging technology, neuronal tracing technique combined with optogenetic manipulation and in vivo calcium imaging, we identified the fear and extinction cells in PrL and BLA and investigated the dynamic encoding of memory engram ensembles in the PrL and BLA during CS versus US initiated memory updating.RESULTS We found increased reactivation of engram cells in the prelimbic cortex and basolateral amygdala during memory updating. Moreover, conditioned stimulus and unconditioned stimulu sinitiated memory updating depend on the engram cells reactivation in the prelimbic cortex or basolateral amygdala respectively. Finally,we found memory updating causes increased overlapping between fear and extinction cells and the original fear engrams encoding was altered during memory updating. CONCLUSION Our data provide the first evidence to show the overlapping ensembles between fear and extinction cells and functional reorganization of original engrams underlying conditioned stimulus and unconditioned stimulus initiated memory updating.
基金supported by the National Science and Technology Major Project(2014ZX09101046-004)the National Natural Foundation of China(31600644)
文摘Cas1-and-Cas2-mediated new spacer acquisition is an essential process for bacterial adaptive immunity.The process is critical for the ecology of the oral microflora and oral health.Although molecular mechanisms for spacer acquisition are known,it has never been established if this process is associated with the morphological changes of bacteria.In this study,we demonstrated a novel Cas2-induced filamentation phenotype in E.coli that was regulated by co-expression of the Cas1 protein.A 30 amino acid motif at the carboxyl terminus of Cas2 is necessary for this function.By imaging analysis,we provided evidence to argue that Cas-induced filamentation is a step coupled with new spacer acquisition during which filaments are characterised by polyploidy with asymmetric cell division.This work may open new opportunities to investigate the adaptive immune response and microbial balance for oral health.
文摘A novel atmospheric plasma device developed in this paper, which is more effective and convenient to study the plasma-initiated polymerization (PIP) than conventional setup. The structure and mechanism of the device is introduced. Some plasma-initiated polymerization experiments are carried out on the device, and the conversion of AA (Acrylic acid) and AM (Acryl amide) atmospheric (N2) plasma polymerization are respectively 89% and 94% after 120 h post polymerization, whereby IR spectra of the product (AA, AM). Our PIP result are confirmed.
文摘The polymerization of methyl acrylate was sensitive to UV light. Under UV light,the rate of polymerization is 8 times as high as the rate in dark.The overall activation energy was decreased by the UV light (313nm).A tentative explanation is given and the mechanism is discussed.
文摘Plasma initiated polymerization is a kind of well-known radical polymerization mechanism, but it has the ＇living＇ polymerization feature and produces ultra-high molecular weight polymer. In order to explain such phenomena, we calculate the basic data of plasma initiated polymerization of methylmethacrylate （MMA） according to the principle of polymer physics and chemistry. It results in that the radical concentration ranges from 10^-12mol/L to 10^-16mol/L corresponding to the radical life in 10^4s to 10^8s, which means the radicals have a long lifetime. Moreover because of the long lifetime radicals it causes a unique feature rather than the common radical polymerization, and also shows no ＂living polymerization＂. It is noticed in experiments that there are two key factors playing important roles. One is the effective radical amount produced during the plasma discharging while the another is the diffusion factor.
文摘he volatile (VPP) and nonvolatile (NVPP) products of methyl methacrylate(MMA) reaction in plasma chamber were used as initiators of MMA polymeriza-tion. From the structure analyses of the two initiators, the measurement of poly-merization kinetics, and the determination of the molecular weight of resultantpolymers , we found tliat MMA polymerization initiated by NVPP is a typical radical mechanism of polymerization which undergoes a process of continuous initiationand bifunction termination , while VPP-initiated polymerization suggested a mech-anism of living radical process fpolymerization with instantaneous initiation , chain-transfer to monomer , without termination).
文摘The integrity of the published record of scientific research depends not only on the validity of the science but also on honesty in authorship. Editors and readers need to be confident that authors have undertaken the work described and have ensured that the manuscript accurately reflects their work, irrespective of whether they took the lead in writing or sought assistance from a medical writer. The scientific record is distorted if the primary purpose of an article is to persuade readers in favor of a special interest, rather than to inform and educate, and this purpose is concealed.
基金The project was supported by the National Natural Science Foundation of Chna.
文摘The homopolymerization of 5-methyl-5-hexen-2,4-dione (methacryloylacetone, MAA), a vinyl monomer having beta-diketone group, was carried out in the presence of benzophenone (BP)/N, N-dimenthyl-4-toluidine (DMT) system. Graft polymerization of acrylamide initiated by eerie ion onto the homopolymer film was investigated and the mechanism of the grafting reaction was proposed on the basis of ESR study. The grafted copolymer was characterized by means of grafting percentage, water absorption, XPS spectra and scanning electron photomicrographs.
文摘The polymerization of acrylamide and acrylonitrile using ceric ion as initiator can be promoted greatly by the tartaric acid. The kinetics of acrylamide polymerization initiated by ceric ion/tartaric acid has been studied. The presence of the species of tartaric acid in Polyacrylonitrile produced by using ceric ion/tartaric acid as niitiator has been confirmed by FT-IR analysis.
文摘<strong>Introduction:</strong> Viral hepatitis is a major public health challenge that requires an urgent response. Reducing mortality requires major scale-up in prevention, testing and treatment access;coverage in HBV vaccination, testing and treatment is low and must accelerate massively to achieve the 2030 targets. Less than 1% of HBV-infected individuals are diagnosed in Sub-Sahara Africa, despite the availability of rapid tests with good diagnostic accuracy. <strong>Materials and Methods:</strong> This was retrospective cross sectional study conducted in Federal Teaching Hospital Gombe, in North East Nigeria. All children and adults who presented to the out-patient departments, and those that were admitted irrespective of their HIV and or Hepatitis C virus status and had Hepatitis B and/or Hepatitis B envelope antigen test were conducted between 2000 to 2015. All children and adults were tested using the Hospital standard for Hepatitis B surface antigen test strip. <strong>Results:</strong> Between 2000 and 2014, 739,456 children and adults were admitted and reviewed in the outpatient units of the Federal Teaching Hospital Gombe;there were 685,552 adults and 53,904 children. Children constituted 7.3% (53,904/739,456) of admissions and outpatient consultations. 2.8% (210/7570), 3.3% (773/23,783), 3.6% (1145/32,142), 5.2% (1694/33,043), 3.3% (986/29,216), 1.9% (661/3321), 0.1% (53/41,626), 0.2% (113/46,634), 2.6% (1418/54,423), 5.4% (3717/69,696), 3.7% (2332/62,086), 3.5% (3241/90,623), 3.2% (2881/89,398), 3.8% (2428/62,687), 2.8% (1835/63,208) of children and adults were tested for HBsAg in 2000, 2001, 20002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011, 2012, 2013 and 2014 respectively. 23,487 children and adults were tested for HBsAg with a cumulative testing rate of 3%. Overall 4465/23,487 children and adults were seropositive for HBsAg giving a cumulative prevalence of 19%. <strong>Conclusion:</strong> HBV screening in our health facility is very low. Massive scale up in awareness and HBV vaccination are required. Provider initiated testing and counseling for HBV in health facilities needs support for implementation in Health Facilities in Sub Saharan Africa.
文摘perfluoroalkyl iodides reacted with alkenes in acetonitrile solu- tion containing catalytic amount of organophosphine under mild condition to give the corresponding adducts in moderate to good yields.Reaction was shown to involve a free radical mechanism.
文摘 On May 20, 2006, General Administration of Quality Sup ervision,Inspection and Quarantine of the P.R.China conducted startup ceremony of "Initiating Resources Conservation Service" to coordinate the activities of propaganda for the seventh World Metrology Day.……
文摘Currently, the application work on 2008 Product Development Contribution Award of China National Textile &Apparel Council, has been initiated, and this award is established
文摘Major progress has been achieved in the development of the prototype of FY-4 meteorological satellite.After two years development,the FY-4 development team with SAST as the leader finished the electrical model of the satellite and passed the preliminary design review.The development of the prototype validation satellite has been initiated.FY-4 will be China's first geostationary Earth observation remote
文摘 A program of ex situ conservation initiated by the CAS to protect the national indigenous flora was revealed recently by a group of CAS scientists in a letter to the prestigious journal 'Science'.……
基金Funded by the Key Project of the Ministry of Science and Technology (No. 96 - 920 - 20 - 21)
文摘The ring-opening polymerization of D, L-lactide in the melt was systematically investigated by using stannous octoate as the initiator. The molecular weight of poly (D, L-lactide) was characterized with M,. Mn and Mw respectively. The results indicated that five variables, namely purity of monomer, initiator to monomer ratio, vacuum level, polymerization temperature and polymerization time had different influences on the molecular weight and molecular weight distribution of poly(D. L-lactide).
基金The Project 29234093 was supported by the National Natural Science Foundation of China.
文摘Acrylamide polymerization initiated with a redox initiation system consisting of eerie ion and ethyl N,N-diethyldithiocarbamyl acetate (EDCA) has been studied. It was found that the polymerization rate equation is in good agreement with that of a redox initiated polymerization, and the overall activation energy of the polymerization was determined to be 25.2 kJ.mol(-1). Accordingly, the system belongs to a redox initiator. The initiation mechanism was proposed based on the end group analysis using FT-IR, UV spectroscopies. Analysis results revealed that the N, N-diethyldithiocarbamyl radical produced from the redox reaction of EDCA with eerie ion can initiate acrylonitrile (AN) polymerization and form the end group on PAN. The resulting PAN was photopolymerized with butyl acrylate (BE) to form PAN-b-PBA block copolymer.
