ABSTRACT
Abstract Several species of Cichla successfully colonized lakes and reservoirs of Brazil, since the 1960s, causing serious damage to local wildlife. In this study, 135 peacock bass were collected in a reservoir complex in order to identify if they represented a single dominant species or multiple ones, as several Cichla species have been reported in the basin. Specimens were identified by color pattern, morphometric and meristic data, and using mitochondrial markers COI, 16S rDNA and Control Region (CR). Overlapping morphological data and similar coloration patterns prevented their identification using the taxonomic keys to species identification available in the literature. However, Bayesian and maximum likelihood from sequencing data demonstrated the occurrence of a single species, Cichla kelberi. A single haplotype was observed for the 16S and CR, while three were detected for COI, with a dominant haplotype present in 98.5% of the samples. The extreme low diversity of the transplanted C. kelberi evidenced a limited number of founding maternal lineages. The success of this colonization seems to rely mainly on abiotic factors, such as increased water transparency of lentic environments that favor visual predators that along with the absence of predators, have made C. kelberi a successful invader of these reservoirs.
Resumo Muitas espécies de Cichla colonizaram com sucesso lagos e reservatórios do Brasil desde os anos 1960, causando graves prejuízos à vida selvagem nesses locais. Neste estudo, 135 tucunarés foram coletados em um complexo de reservatórios a fim de identificar se representavam uma espécie dominante ou múltiplas espécies, uma vez que diversas espécies de Cichla foram registradas na bacia. Os espécimes foram identificados com base na coloração, dados morfométricos e merísticos, e por marcadores mitocondriais COI, 16S rDNA e Região Controle (RC). A sobreposição dos dados morfométricos e o padrão similar de coloração impediram a identificação utilizando as chaves de identificação disponíveis na literatura. Entretanto, as análises bayesiana e de máxima verossimilhança de dados moleculares demonstraram a ocorrência de uma única espécie, Cichla kelberi. Um único haplótipo foi observado para o 16S e RC, enquanto três foram detectados para o COI, com um haplótipo dominante presente em 98,5% das amostras. A baixa diversidade nos exemplares introduzidos de C. kelberi evidenciou um número limitado de linhagens maternas fundadoras. O sucesso da invasão parece depender de fatores abióticos, como a maior transparência da água de ambientes lênticos que favorece predadores visuais que, atrelado à ausência de predadores, fez do C. kelberi um invasor bem-sucedido nesses reservatórios.
ABSTRACT
Abstract Several species of Cichla successfully colonized lakes and reservoirs of Brazil, since the 1960's, causing serious damage to local wildlife. In this study, 135 peacock bass were collected in a reservoir complex in order to identify if they represented a single dominant species or multiple ones, as several Cichla species have been reported in the basin. Specimens were identified by color pattern, morphometric and meristic data, and using mitochondrial markers COI, 16S rDNA and Control Region (CR). Overlapping morphological data and similar coloration patterns prevented their identification using the taxonomic keys to species identification available in the literature. However, Bayesian and maximum likelihood from sequencing data demonstrated the occurrence of a single species, Cichla kelberi. A single haplotype was observed for the 16S and CR, while three were detected for COI, with a dominant haplotype present in 98.5% of the samples. The extreme low diversity of the transplanted C. kelberi evidenced a limited number of founding maternal lineages. The success of this colonization seems to rely mainly on abiotic factors, such as increased water transparency of lentic environments that favor visual predators that along with the absence of predators, have made C. kelberi a successful invader of these reservoirs.
Resumo Muitas espécies de Cichla colonizaram com sucesso lagos e reservatórios do Brasil desde os anos 1960, causando graves prejuízos à vida selvagem nesses locais. Neste estudo, 135 tucunarés foram coletados em um complexo de reservatórios a fim de identificar se representavam uma espécie dominante ou múltiplas espécies, uma vez que diversas espécies de Cichla foram registradas na bacia. Os espécimes foram identificados com base na coloração, dados morfométricos e merísticos, e por marcadores mitocondriais COI, 16S rDNA e Região Controle (RC). A sobreposição dos dados morfométricos e o padrão similar de coloração impediram a identificação utilizando as chaves de identificação disponíveis na literatura. Entretanto, as análises bayesiana e de máxima verossimilhança de dados moleculares demonstraram a ocorrência de uma única espécie, Cichla kelberi. Um único haplótipo foi observado para o 16S e RC, enquanto três foram detectados para o COI, com um haplótipo dominante presente em 98,5% das amostras. A baixa diversidade nos exemplares introduzidos de C. kelberi evidenciou um número limitado de linhagens maternas fundadoras. O sucesso da invasão parece depender de fatores abióticos, como a maior transparência da água de ambientes lênticos que favorece predadores visuais que, atrelado à ausência de predadores, fez do C. kelberi um invasor bem-sucedido nesses reservatórios.
Subject(s)
Animals , Cichlids/genetics , Phylogeny , Genetic Variation/genetics , Haplotypes/genetics , Lakes , Bayes TheoremABSTRACT
Constraint-based genome-scale metabolic network models (genome-scale metabolic models, GEMs) have been widely used to predict metabolic phenotypes. In addition to stoichiometric constraints, other constraints such as enzyme availability and thermodynamic feasibility may also limit the cellular phenotype solution space. Recently, extended GEM models considering either enzymatic or thermodynamic constraints have been developed to improve model prediction accuracy. This review summarizes the recent progresses on metabolic models with multiple constraints (MCGEMs). We presented the construction methods and various applications of MCGEMs including the simulation of gene knockout, prediction of biologically feasible pathways and identification of bottleneck steps. By integrating multiple constraints in a consistent modeling framework, MCGEMs can predict the metabolic bottlenecks and key controlling and modification targets for pathway optimization more precisely, and thus may provide more reliable design results to guide metabolic engineering of industrially important microorganisms.
Subject(s)
Genome , Metabolic Engineering , Metabolic Networks and Pathways/genetics , Models, Biological , ThermodynamicsABSTRACT
Flavonoids is one of the biggest families of the plant-derived secondary metabolites with structural diversity. Until now, over 10 000 kinds of flavonoids with distinct structures have been purified and identified from plants, and some of them possess a range of important pharmacological effects, such as anticancer, anti-inflammatory and so on. So far, a number of genes and enzymes responsible for the biosynthesis of flavonoids have been reported, especially, a great of progress has been achieved in the synthetic biology of flavonoids in the recent years. Herein, based upon a brief introduction on the biosynthesis of flavonoids, this review summarizes the research advances in synthetic biology of flavonoids in the past two decades (2001-2021), highlighting the cell factories construction of the representative flavonoids. And, a brief discussion and prospects of the relevant metabolic bottlenecks and optimizing strategies are proposed.
ABSTRACT
The Neotropical catfish genus Pseudoplatystoma comprises eight species of large size, widely distributed in South American basins. The endangered species P. magdaleniatum is endemic to Magdalena basin (Colombia), experiences high fishing pressure and its population genetics is relatively unknown. To study the genetic status and structure of P. magdaleniatum, 25 species-specific polymorphic microsatellite loci were developed using next-generation sequencing and then tested in samples collected in the Magdalena-Cauca basin. Based on 15 of these loci, P. magdaleniatum showed a high number of alleles per locus (9-10), high values of observed (0.762-0.798) and expected (0.770-0.791) heterozygosities, recent reduction of population size and gene flow. These findings constitute a baseline to measure potential changes in genetic diversity and structure of this commercially important species in a basin undergoing high anthropogenic activities.(AU)
El género de bagres neotropicales Pseudoplatystoma comprende ocho especies de gran tamaño, ampliamente distribuidas en las cuencas de Suramérica. La especie en peligro de extinción P. magdaleniatum es endémica de la Cuenca del Magdalena (Colombia), experimenta una alta presión pesquera y su genética poblacional es relativamente desconocida. Para estudiar el estado y estructura genética de P. magdaleniatum, se desarrollaron 25 loci microsatélites polimórficos especie específicos utilizando secuenciación de próxima generación y se evaluaron en muestras recolectadas en la Cuenca del Magdalena-Cauca. Con base en 15 loci, P. magdaleniatum mostró un alto número de alelos por locus (9-10), valores altos de heterocigosidad observada (0.762-0.798) y esperada (0.770-0.791), reducción reciente del tamaño poblacional y flujo génico. Estos hallazgos constituyen una línea de base para medir cambios potenciales en la diversidad y estructura genética de esta especie comercialmente importante en una cuenca sometida a altas actividades antropogénicas.(AU)
Subject(s)
Animals , Genetic Variation , Weights and Measures , Catfishes , Microsatellite Repeats , Endangered SpeciesABSTRACT
Currently, the domestic and foreign research methods for the qualitative basis of Chinese materia medica (CMM) mainly include phytochemical separation method, pharmacological activity tracer method, chromatography, etc. The above methods have played an active role in elucidating the qualitative basis of CMM. However, how to form a multi-component research model that can better reflect the "holistic view" characteristics of CMM and reflect the effectiveness of CMM has become an important direction for scholars in the industry to explore. Serum spectrum-effect of CMM is based on the theory of spectrum-effect to study the relationship between serum chemical fingerprints and pharmacodynamics in vivo. In this paper, by consulting relevant literature, the research idea of serum spectrum-effect was collected, the research results were summarized, and the research bottleneck was analyzed and discussed, so as to provide reference for revealing the material basis of CMM.
ABSTRACT
This study proposes an image segmentation method based on bottleneck detection and watershed algorithm to solve the problem of overlapping cervical cell image. First, we use polygon approximation to get all feature points on the cell contour and then use bottleneck detection and ellipse fitting to obtain the correct split point pairs. Therefore, the approximate range of the overlapping region was determined. The watershed algorithm was used to obtain the internal boundary information for the gradient image of the region. Finally, the segmentation results of the overlapped cells were obtained by superimposing with the outer contour. The experimental results show that this algorithm can segment the contour of a single cell from the overlapping cervical cell images with good accuracy and integrity. The segmentation result is close to that of doctors' manual marking, and the segmentation result is better than other existing algorithms.
Subject(s)
Female , Humans , Algorithms , Cervix Uteri/cytology , Image Processing, Computer-AssistedABSTRACT
O objetivo do presente trabalho foi avaliar a variabilidade genética de larvas e alevinos de piracanjuba em programa de repovoamento. Foram coletadas 180 larvas de piracanjuba de três dias e 90 alevinos de três meses de idade. Foram avaliados cinco loci microssatélites, os quais produziram 19 alelos. Não houve presença de alelos raros nem perdas de alelos ao longo do período. A heterozigosidade observada foi superior nas larvas em relação aos alevinos. Houve desvio no equilíbrio de Hardy-Weinberg na maioria dos loci em ambos os grupos. O coeficiente de endogamia foi positivo em ambos os grupos, sendo a média dos alevinos superior em relação às larvas. O excesso de heterozigotos foi significativo no modelo Stepwise Mutation Model para os alevinos, indicando a possibilidade de efeito gargalo recente. Conclui-se que, apesar da adequada variabilidade genética encontrada, os valores do coeficiente de endogamia e a possibilidade de efeito gargalo nos alevinos atentam para a necessidade de constante monitoramento genético desses estoques antes da liberação no ambiente.(AU)
The objective of this study was to evaluate the genetic variability of Piracanjuba larvae and fingerlings in restocking program. A total of 180 three-day Piracanjuba larvae and 90 three-month-old fish were sampled. Five microsatellite loci were evaluated, which produced 19 alleles. There were no rare alleles or loss of alleles over the period. The observed heterozygosity was higher in larvae compared to fingerlings. There was a deviation in Hardy-Weinberg equilibrium in most loci in both groups. The inbreeding coefficient was positive in both groups, with the average of the fingerlings superior to the larvae. The excess heterozygotes were significant in the Stepwise Mutation Model for the fingerlings, indicating the possibility of a recent bottleneck effect. Despite the adequate genetic variability found, the values of the inbreeding coefficient and the possibility of bottleneck effect in the fingerlings show the need for constant genetic monitoring of these stocks prior to release into the environment.(AU)
Subject(s)
Animals , Fishes , Biological Variation, Population , InbreedingABSTRACT
Abstract Genotypes of 10 microsatellite loci of 420 humpback whales from the Southwestern Atlantic Ocean population were used to estimate for the first time its contemporary effective (Ne) and census (Nc) population sizes and to test the genetic effect of commercial whaling. The results are in agreement with our previous studies that found high genetic diversity for this breeding population. Using an approximate Bayesian computation approach, the scenario of constant Ne was significantly supported over scenarios with moderate to strong size changes during the commercial whaling period. The previous generation Nc (Ne multiplied by 3.6), which should corresponds to the years between around 1980 and 1990, was estimated between ~2,600 and 6,800 whales (point estimate ~4,000), and is broadly compatible with the recent abundance surveys extrapolated to the past using a growth rate of 7.4% per annum. The long-term Nc in the constant scenario (point estimate ~15,000) was broadly compatible (considering the confidence interval) with pre-whaling catch records estimates (point estimate ~25,000). Overall, our results shown that the Southwestern Atlantic Ocean humpback whale population is genetically very diverse and resisted well to the strong population reduction during commercial whaling.
ABSTRACT
In order to figure out phylogenetic relationship and genetic diversity of different geographical populations,genetic analyses of Aedes albopictus were performed based on mitochondrial gene COI.Based on samples collected from most distribution regions in China,mitochondrial gene Cytochrome C Oxidase Subunit I was obtained through PCR and DNA sequence.Together with some COI sequences downloaded from GenBank,60 COI sequences with the final length of 598 bp were used for subsequent analyses.Results showed that there was no obvious divergence according to phylogenetic analyse,all sequences were clustered together in Maximum Likelihood tree.Sixteen haplotypes were detected,and four of them shared haplotypes.Haplotype diversity (Hd) was 0.737,nucleotide diversity (π) was 0.20 ％.Population genetic differentiation analyses demon strated that Hainan population showed obvious divergences.In the network of haplotypes,H1 and H6 was found to be the primary haplotypes,and they formed two radical centers.All these results indicate that A.albopictus populations of China are expanding presently,and Hainan population become differential with other geographical populations,which probably attribute to geographical isolations.
ABSTRACT
Objective To explore the present situation and measures of medical equipment personnel training with considerations on idea of precision interaction and precision service as well as the viewpoint of supply side.Methods The present situation and requirements of medical equipment personnel training were analyzed with the methods of literature query,field survey,questionnaire survey,panel discussion,expert consultation and etc.Results Medical equipment personnel shortages occurred in management,research,development and other fields,and efforts had to be executed from the aspects of policy,industrial idea and etc.Conclusion A multi-dimension medical equipment personnel training system has to be established involving in personnel training,development and utilization.
ABSTRACT
Objective To explore the present situation and measures of medical equipment personnel training with considerations on idea of precision interaction and precision service as well as the viewpoint of supply side.Methods The present situation and requirements of medical equipment personnel training were analyzed with the methods of literature query,field survey,questionnaire survey,panel discussion,expert consultation and etc.Results Medical equipment personnel shortages occurred in management,research,development and other fields,and efforts had to be executed from the aspects of policy,industrial idea and etc.Conclusion A multi-dimension medical equipment personnel training system has to be established involving in personnel training,development and utilization.
ABSTRACT
OBJECTIVE:To provide experience and reference for the reform ofintegration of medicine and nursingunder the strategy ofHealth China 2030. METHODS:By literature analysis,the demand characteristics and supply situation ofinte-gration of medicine and nursingservice model in China were analyzed. The development bottleneck ofintegration of medicine and nursingservice model in China was discussed to put forward countermeasures and suggestions. RESULTS&CONCLUSIONS:Integration of medicine and nursingis a new model of the development of pension services in China. Throughout whole country, it is still in the stage of exploration and practice. There are some problems,such as serious inadequate beds,low participation of private pension institutions,pension service quality ofintegration of medicine and nursinghaving to be improved,weak market competition of pension institutions,social forces participation having to be improved,big demand gap of medical and nursing staff,inadequate high-quality medical and nursing talent. A clear positioning ofintegration of medicine and nursingservice model in China should be put forward andintegration of medicine and nursingmonitoring system should be improved. It is suggested to establish service complaint mechanism of pension institutions,encourage the active participation of diverse social forces,broaden the financing channels ofintegration of medicine and nursing,build service information sharing platform ofintegration of medi-cine and nursing,establish electronic health records for the elderly and set up maintenance personnel training mechanism so as to promote the rapid development of the reform ofintegration of medicine and nursing.
ABSTRACT
Despite success in scaling up immunization, the national immunization programme in Bangladesh remains challenged by persisting inequities in health access related to geographic location and social factors, including income and education status. In order to tackle these inequities in access, the national immunization programme has conducted a field trial of the evidence-based planning model in Bangladesh between 2011 and 2013, in 11 low-performing districts and 3 city corporations. The main elements of this intervention included bottleneck analysis in local areas, action planning and budgeting to correct the bottlenecks, and establishment of a monitoring system to track progress. Coverage improved in 8 out of 14 districts post intervention. The main success factors associated with the intervention included more analytic approaches to situation assessment and taking action on health inequities at the local level, as well as more considered use of local data to track immunization drop-outs. The main factors associated with coverage declines in trial areas (6 districts) included poor financial resourcing and supervisory support, and gaps and turnover in human resources. In order to sustain and improve coverage, it will be necessary in future to link pro-equity approaches to subdistrict planning to higher-level health-system-strengthening strategy and planning systems. This will ensure that local area planners have the required resources, comprehensive operational plans and political support to sustain implementation of corrective actions to address identified system bottlenecks and inequities in health access at the local level.
ABSTRACT
The genetic diversity of the specimens of four natural populations of Arapaima from Araguaia-Tocantins basin was assessed within and among these stocks, using five primers for ISSR. COI (cytochrome c oxidase subunit I) partial sequences confirmed that the specimens belongs to Arapaima gigas. The ISSR provided 168 loci, of which 165 were polymorphic. However, the number of loci for each population and expected heterozygosity values were low. AMOVA showed 52.63% intra-population variation and 47.37% inter-population variation. The F ST was high among all populations (F ST ≥ 0.25), however, the cluster analysis (PCoA) and Bayesian inference showed three major groups: Araguaiana-MT + São Félix do Araguaia-MT, Novo Santo Antônio-MT and Itupiranga-PA. The genetic distance was not correlated with geographical distance. The ISSR marker revealed that the populations of the Araguaia-Tocantins are structured and have a low genetic diversity. These are the first data from a population analysis using molecular markers for A. gigas of Araguaia-Tocantins basins and may be used to define the best management strategies and conservation projects for this species.
A diversidade genética dos espécimes de quatro populações naturais de Arapaima coletados na bacia do Araguaia-Tocantins foi avaliada com base em cinco primers para marcadores moleculares ISSR. A sequência parcial do COI (cytochrome c oxidase subunit I) confirmou que os espécimes pertencem à espécie Arapaima gigas. Os ISSR forneceram 168 loci, dos quais 165 polimórficos. No entanto, para cada população, os valores de heterozigosidade esperada foram baixos. A AMOVA mostrou 52,63% de variação intrapopulacional e 47,37% interpopulacional. O F ST foi alto entre todas as populações (F ST ≥ 0,25); entretanto, a análise de agrupamento e a inferência Bayesiana mostraram três grandes grupos: Araguaiana-MT + São Félix do Araguaia-MT, Novo Santo Antônio-MT e Itupiranga-PA. A distância genética não teve correlação com a distância geográfica. Os ISSRs se mostraram eficientes para determinar a diversidade genética para a A. gigas, revelando que as populações da bacia Araguaia-Tocantins estão estruturadas e com baixa diversidade genética. Estes são os primeiros dados de análise populacional utilizando ISSR para A. gigas da bacia Araguaia-Tocantins e poderão ser utilizados para definir as melhores estratégias de manejo e projetos de conservação dessa espécie.
Subject(s)
Animals , Characiformes/genetics , Genetic Variation/physiologyABSTRACT
Medical scientific research is the main driving force of development of medical science.In order to ensure the Hospital take the road of sustainable development in a market economy environment,We must rely on technologIcal progress and innovation to improve the comprehensive competitiveness of the hospital.Through analysis the present of our hospital scientific research,Proposed the bottleneck problem how to maintain the momentum of scientific research development.And on this basis investigate the hospital scientific research trends:Achieve major breakthrough in scientific research; To Create scientific For the sake of research team with strong competitiveness,To Strengthen personnel training gradient,reserve new force for development of hospital's scientific research; Apply for the high level scientific research projects,Strengthen the regulatory regime of the scientific research projects; Around a stable long-term scientific research direction to do depth research; Ensure The hospital's scientific research work on a sustainable development path.
ABSTRACT
Genetic structure of a group of capybaras, Hydrochoerus hydrochaeris (Rodentia: Hydrocheridae) in the Colombian Eastern Llanos. The capybaras are the biggest rodents in the world but, however, there are not extensive population genetics studies on them. In the current work, we studied the genetic structure of a troop of 31 capybaras (Hydrochoerus hydrochaeris) sampled in Hato Corozal, Casanare Department at the Colombian Eastern Llanos, by means of five microsatellite markers. The gene diversity was 0.61 and the average allele number was 5.2, which is a medium-low level for markers of this nature. Out five markers employed, three were in Hardy-Weinberg equilibrium meanwhile one showed a significant homozygote excess and other presented a significant heterozygote excess. There were not significant genetic differences between males and females inside this troop. The application of different procedures to determine possible historical demographic changes (population expansions or bottlenecks) clearly showed that the population analyzed crossed over a very narrow recent bottleneck. The illegal hunt is the possibly cause of this strong genetic bottleneck. Rev. Biol. Trop. 59 (4): 1777-1793. Epub 2011 December 01.
Los capibaras son los roedores más grandes del mundo, sin embargo, no se han realizado estudios genético poblacionales exhaustivos con ellos. En el presente trabajo se analizó la estructura genética de una manada de 31 capibaras (Hydrochoerus hydrochaeris) muestreada en Hato Corozal, Departamento de Casanare en los Llanos Orientales de Colombia, mediante cinco marcadores microsatelitales. La diversidad genética se determinó en 0.61 y un número promedio de alelos de 5.2, lo cual se puede considerar medio-bajo para este tipo de marcadores. De los cinco marcadores empleados, tres mostraron proporciones genotípicas en concordancia con lo esperado en equilibrio Hardy-Weinberg, mientras que un marcador mostró un exceso significativo de homocigotos y otro un exceso significativo de heterocigotos. No se encontraron diferencias significativas para esos cinco marcadores entre machos y hembras de la manada muestreada. La aplicación de diferentes procedimientos para detectar posibles cambios demográficos históricos (expansiones poblacionales o cuellos de botella) mostró claramente que la población analizada ha pasado por un cuello de botella extremadamente fuerte en épocas recientes. La limitada variabilidad genética encontrada y la fuerte evidencia de que la manada estudiada ha pasado por un cuello de botella reciente es probablemente el resultado de la cacería ilegal.
Subject(s)
Animals , Female , Male , Genetics, Population , Genetic Variation/genetics , Microsatellite Repeats/genetics , Rodentia/genetics , Colombia , GenotypeABSTRACT
Up to date, little is known about the relationship between historical demography and the current genetic structure of A. Angus As a first effort towards overcoming this lack, microsatellite data scored in six populations and isozyme allele frequencies published for 11 natural stands of this species were analysed in order to assess molecular signatures of populations' demographic history. Signatures of genetic bottlenecks were captured in all analysed populations of southeastern Brazil. Among southern populations, signatures of small effective population size were observed in only three out of 13 populations. Southern populations likely experienced faster recovery of population size after migration onto highlands. Accordingly, current genetic diversity of the southern populations gives evidence of fast population size recovery. In general, demographic history of A. Angusmatches climatic dynamics of southern and southeastern Brazil during the Pleistocene and Holocene. Palynological records and reconstruction of the past climatic dynamics of southeastern and southern Brazil support the hypothesis of different population size recovery dynamics for populations from these regions.
Até o momento, pouco se conhece sobre a relação entre história demográfica e a presente estrutura genética da A. Angus Como uma primeira tentativa em transpor esta deficiência, dados de microssatélites coletados em seis populações e freqüências alélicas de isoenzimas publicadas para 11 populações naturais desta espécie foram analisadas com o objetivo de acessar assinaturas moleculares da história demográfica populacional. Assinaturas de gargalos genéticos foram capturadas em todas as populações analisadas provenientes do Sudeste do Brasil. Entre as populações do Sul, assinaturas de pequeno tamanho populacional efetivo foram observadas em somente três entre 13 populações. Populações do Sul provavelmente apresentaram uma rápida recuperação do tamanho efetivo após a migração para os planaltos. Em acordança, a presente diversidade genética das populações do Sul apresenta evidências de uma rápida recuperação do tamanho populacional. Em geral, a história demográfica da A. Angus concorda com as dinâmicas climáticas do Sul e Sudeste do Brasil durante o Pleistoceno e o Holoceno. Estudos palinológicos e reconstrução de dinâmicas climáticas do Sul e Sudeste do Brasil suportam a hipótese de diferentes dinâmicas de recuperação do tamanho populacional em populações destas regiões.
Subject(s)
Tracheophyta/genetics , Gene Frequency , Genetic Variation , Microsatellite Repeats/genetics , Brazil , GenotypeABSTRACT
Biodiesel, a nontoxic,cleaning, renewable and biodegradable fuel, is expected as a substitute for conventional fossil diesel. There are three main approaches to produce biodiesel, alkali-catalysis processing, enzymatic-catalysis processing and supercritical processing. With the unique property of energy-saving and environment-friendly, enzymatic-catalysis appears a great potential for industrial application. The main bottleneck of this technology is high cost and low stability of the lipase, as well as the inactivation of lipase by methanol and so on. To settle the problem, several methods have been used including the fixed-bed bioreactor, enzyme immobilized processing, whole-cell biocatalyst, changing addition method of methanol, developing of novel acyl acceptor, enhancing methanol resistance of lipase. The main problems and the relative strategy research of the enzymatic-catalysis technology were sum up.
ABSTRACT
Objective To evaluate arthroscopic PCL (posterior cruciate ligament) reconstruction with an implant fixaliun of hamstring tendon knot and bottle-neck technique.Methods Thirteen cases with PCL injury were treated with arthroscopic PCL reconstruction with an implant fixation of hamstring tendon knot and bottle-neck technique between April,2002 to June,2005.The patients were followed up fur at least seven months to evaluate the clinical effects by means of ROM of the joint,post drawer test,Lachman test,Lysholm and IKDC (International Knee Documents Committee) scores.Results The patients were followed up for an average of 13.4 months.No limitation of knee extension was found six months after operation.Eleven patients had normal knee flexion(＞140?), one had knee flexion of 120?and one 100?.In posterior drawer test,11 patients were gradeⅠand two gradeⅡ.In Lachman test,11 patients were rated as within gradeⅠand two gradeⅡ.By Lysholm knee function scale,the average knee scores were 90.47?4.13 and 78.82?2.46 respectively before and after operation,and the dif- ference was of statistical significance (t=2.416,P=0.029).By IKDC scale,six were grade A,five grade B and one grade C.Conclusion Arthroseopic PCL reconstruction with an implant fixation of hamstring tendon knot and bottle-neck technique is a reliable method to restore knee function and will have a prospect of wide application be- cause of its good tissue biocompatibility,less invasion,and less operative expenditure.