Effects of environmental stability and phycoperiphyton structure on the macroinvertebrate community of regulated Andean rivers / Efectos de la estabilidad ambiental y estructura del ficoperifiton en la comunidad de macroinvertebrados en ríos andinos regulados

Introduction: The variability in the structure of aquatic communities is frequently attributed to environmental changes; however, in stable environments such as regulated rivers, trophic interactions could be another key environmental factor determining the structure of these communities. These alterations could cause a greater growth of algae, and in turn, changes in the functional groups and in the composition of the macroinvertebrate community favoring the dominance of certain groups of organisms. Objective: To identify the effects of environmental variations and changes in the structure of the phycoperiphyton on the macroinvertebrate community of regulated Andean rivers. Methods: We analyzed environmental and biological data collected in quarterly samples carried out between 2010 and 2018 in two rivers of the Central Andes (Antioquia - Colombia), for a total of 27 samples. Sample collections used standardized methods. Different statistical models were used to establish spatial and temporal patterns of the environmental variables, of the abundance and/or density and diversity of phycoperiphyton and macroinvertebrates, as well as the trophic relationships that exists between them. Results: We found that regulated rivers present relatively little environmental variability. The environmental parameters with the greatest variation were temperature, turbidity, and orthophosphates; these last two were the abiotic variables with the greatest contribution to benthic instability. Conclusion: The presence of scraping and foraging macroinvertebrates was more affected by the stability of the phycoperiphyton density than by environmental variables, showing the importance of trophic interactions in regulated rivers and the bottom up control in these ecosystems.

Introducción: La variabilidad en la estructura de las comunidades acuáticas se atribuye frecuentemente a cambios ambientales, no obstante, en ambientes estables como ríos regulados, las interacciones tróficas podrían ser otro factor ambiental clave determinante de la estructura de estas comunidades. Estas alteraciones podrían provocar un mayor crecimiento de algas y, a su vez, cambios en los grupos funcionales y en la composición de la comunidad de macroinvertebrados favoreciendo la dominancia de determinados grupos de organismos. Objetivo: Identificar el efecto de los cambios ambientales y de la estructura del ficoperifiton sobre la comunidad de macroinvertebrados de ríos Andinos regulados. Métodos: Se analizaron datos ambientales y biológicos recolectados en muestreos trimestrales realizados entre 2010 y 2018 en dos ríos de los Andes Centrales (Antioquia - Colombia), para un total de 27 muestras. La recolección de muestras empleó métodos estandarizados. Se utilizaron diferentes modelos estadísticos para establecer patrones espaciales y temporales de las variables ambientales, de la abundancia y/o densidad y diversidad de ficoperifiton y de los macroinvertebrados, así como las relaciones tróficas que existen entre ellos. Resultados: Se encontró que los ríos regulados presentan relativamente poca variabilidad ambiental. Los parámetros ambientales con mayor variación fueron: temperatura, turbidez y ortofosfatos; las dos últimas variables abióticas fueron las que más aportaron a la inestabilidad bentónica. Conclusión: La presencia de macroinvertebrados raspadores y recolectores fue más afectada por la estabilidad de la densidad del ficoperifiton que por las variables ambientales, evidenciando la importancia de las interacciones tróficas en ríos regulados y el control bottoom up en estos ecosistemas.

Influence of foliar application of glycinebetaine on Tagetes erecta L yield cultivated under salinity conditions / Influência da aplicação foliar de glicinebetaína na produtividade de Tagetes erecta L cultivada em condições de salinidade

Tagetes genus of Composite family consider one of the most favorite floriculture plants. Therefore, of particular interest examine the salt tolerance of this bedding and coloring agent plant. In this research, was report the role of glycinebetaine (GB) in attenuating the adverse impacts of salt stress in African marigold plant, along with their anti-oxidative capacities and biochemical attributes. The salt stressed African marigold (100 and 150 mM NaCl) was treated with GB at 200 mM, beside untreated control plants. According to the obtained results, the growth characters were negatively in salt stressed plants but a mitigate impact of GB were observed in this respect. Obviously, the morphological as well as some physiological characters were reduced with salinity treatments while GB treatment reverses these effects. Overall, the alleviate impact of GB on the negative impact of salt stress was enhanced through improving total phenolic and antioxidant enzyme activity. Further, it is concluded that GB concentration induces the activities of antioxidative enzymes which scavenged ROS increased under saline conditions.

O Tagetes, da família Composite, é um dos gêneros mais apreciados de plantas de floricultura. Portanto, é de particular interesse examinar a tolerância ao sal desta planta de substrato e corante. Nesta pesquisa, foi relatado o papel da glicinebetaína (GB) na atenuação dos impactos adversos do estresse salino na calêndula africana, juntamente com suas capacidades antioxidantes e atributos bioquímicos. A calêndula africana estressada com sal (NaCl 100 e 150 mM) foi tratada com GB a 200 mM, ao lado de plantas de controle não tratadas. De acordo com os resultados obtidos, os caracteres de crescimento foram negativos em plantas estressadas por sal, mas um impacto mitigado de GB foi observado neste aspecto. Obviamente, os caracteres morfológicos e fisiológicos foram reduzidos com os tratamentos de salinidade, enquanto o tratamento com GB reverteu esses efeitos. No geral, o impacto de alívio do GB no impacto negativo do estresse salino foi aprimorado através da melhoria da atividade das enzimas fenólicas e antioxidantes totais. Além disso, conclui-se que a concentração de GB induz as atividades de enzimas antioxidantes que sequestraram ROS aumentadas em condições salinas.

Influence of foliar application of glycinebetaine on Tagetes erecta L yield cultivated under salinity conditions

Abstract Tagetes genus of Composite family consider one of the most favorite floriculture plants. Therefore, of particular interest examine the salt tolerance of this bedding and coloring agent plant. In this research, was report the role of glycinebetaine (GB) in attenuating the adverse impacts of salt stress in African marigold plant, along with their anti-oxidative capacities and biochemical attributes. The salt stressed African marigold (100 and 150 mM NaCl) was treated with GB at 200 mM, beside untreated control plants. According to the obtained results, the growth characters were negatively in salt stressed plants but a mitigate impact of GB were observed in this respect. Obviously, the morphological as well as some physiological characters were reduced with salinity treatments while GB treatment reverses these effects. Overall, the alleviate impact of GB on the negative impact of salt stress was enhanced through improving total phenolic and antioxidant enzyme activity. Further, it is concluded that GB concentration induces the activities of antioxidative enzymes which scavenged ROS increased under saline conditions.

Resumo O Tagetes, da família Composite, é um dos gêneros mais apreciados de plantas de floricultura. Portanto, é de particular interesse examinar a tolerância ao sal desta planta de substrato e corante. Nesta pesquisa, foi relatado o papel da glicinebetaína (GB) na atenuação dos impactos adversos do estresse salino na calêndula africana, juntamente com suas capacidades antioxidantes e atributos bioquímicos. A calêndula africana estressada com sal (NaCl 100 e 150 mM) foi tratada com GB a 200 mM, ao lado de plantas de controle não tratadas. De acordo com os resultados obtidos, os caracteres de crescimento foram negativos em plantas estressadas por sal, mas um impacto mitigado de GB foi observado neste aspecto. Obviamente, os caracteres morfológicos e fisiológicos foram reduzidos com os tratamentos de salinidade, enquanto o tratamento com GB reverteu esses efeitos. No geral, o impacto de alívio do GB no impacto negativo do estresse salino foi aprimorado através da melhoria da atividade das enzimas fenólicas e antioxidantes totais. Além disso, conclui-se que a concentração de GB induz as atividades de enzimas antioxidantes que sequestraram ROS aumentadas em condições salinas.

Tillering dynamics in spring and summer of marandu palisade grass pastures previously used under deferred grazing / [Dinâmica de perfilhamento na primavera e no verão de pastagens de capim-marandu previamente utilizadas sob pastejo diferido]

This work was conducted to evaluate the effect of deferred pasture condition of Brachiaria brizantha cv. Marandu in the late winter on tillering during the growing season. The treatments were three pasture conditions at late winter: short pasture, tall pasture and tall/mown pasture. In September and October, tiller appearance rate (TApR) and tiller mortality rate (TMoR) were greater in the tall/mown pasture. In November and December, tall pasture presented greater TApR. From November to January the TMoR was greater in the tall pasture. The tiller stability index of short and tall/mown pastures were greater in October. The short pasture presented a greater tiller number than the tall and tall/mown pastures during the entire experimental period. Deferred and short pasture of marandu palisade grass at late winter presents in general lower tiller mortality and higher population density of tillers from the early spring onwards, in comparison to tall pasture. The mowing of marandu palisade grass with high forage mass at the late winter, although it only temporarily compromises the population stability of tillers, also stimulates its fast tillering from spring on.(AU)

Este trabalho foi conduzido com o objetivo de avaliar o efeito da condição da pastagem diferida de Brachiaria brizantha cv. Marandu ao final do inverno sobre o perfilhamento durante a estação de crescimento. Os tratamentos foram três condições de pastagem no final do inverno: pasto baixo, pasto alto e pasto alto/roçado. Nos meses de setembro e outubro, a taxa de aparecimento de perfilhos (TApP) e a taxa de mortalidade de perfilhos (TMoP) foram maiores na pastagem alta/roçada. Nos meses de novembro e dezembro, a pastagem alta apresentou maior TApP. De novembro a janeiro, a TMoP foi maior na pastagem alta. Os índices de estabilidade de perfilhos das pastagens baixas e altas/roçadas foram maiores em outubro. A pastagem baixa apresentou maior número de perfilhos do que as pastagens altas e altas/roçadas durante todo o período experimental. A pastagem diferida e baixa de capim-marandu no final do inverno apresenta, em geral, menor mortalidade de perfilhos e maior densidade populacional de perfilhos no início da primavera, em comparação com a pastagem alta. A roçada do capim-marandu com alta massa de forragem ao final do inverno, embora comprometa apenas temporariamente a estabilidade populacional dos perfilhos, também estimula o perfilhamento rápido a partir da primavera.(AU)

Preparation of berberine hydrochloride dry powder inhalation and its effect on Staphylococcus aureus pneumonia / 中草药

Objective: To prepare berberine hydrochloride dry powder inhalation, and investigate its pharmacological effect on Staphylococcus aureus pneumonia after pulmonary administration. Methods: Berberine hydrochloride dry powder by spray drying and the experimental conditions was optimized by orthogonal experiment. The lung deposition, fluidity and appearance were characterized. The pharmacodynamic effects of the preparations on S. aureus pneumonia were performed with SD rats. Results: A berberine hydrochloride dry powder was prepared at an inlet temperature of 130 ℃ with a gas volume flow of 610 L/h and a feed volume flow of 3 mL/min. The berberine hydrochloride dry powder had a lung deposition rate (FPF) of 76.4% and an aerodynamic diameter of 4.61 μm. The stability index (SI) ≈ 1, the aeration energy ratio (AR) = 1.76 > 1, and the inflation energy (AE10) = 2.1 mJ < 10 mJ. Through the pharmacodynamic evaluation of S. aureus, we can know that the berberine hydrochloride dry powder inhalation effectively improved the pathological state of pneumonia rats, and significantly reduced (P < 0.05) the number of WBC, neutrophils, and the expression of inflammatory factors (TNF-α, IL-1β, and IL-6) in pneumonia rats. Conclusion: Berberine hydrochloride dry powder inhalation can directly reach the lesion site through pulmonary administration, so it has significant therapeutic effect on S. aureus pneumonia.

Perfilhamento do capim-piatã submetido a regimes de desfolhação intermitente / Tillering of piatã grass subject intermittent cutting

Objetivou-se avaliar o perfilhamento da Brachiaria brizantha cv. Piatã, como base para identificação das frequências e alturas pós-corte mais adequadas para essa gramínea forrageira. Em um esquema fatorial 2 x 2, foram estudadas combinações entre duas frequências de corte (95% e máxima interceptação de luz, ILmax) e duas alturas pós-corte (15 e 20cm). O delineamento foi em blocos ao acaso, com três repetições, totalizando 12 unidades experimentais de 14m2 cada. Foram avaliadas as taxas de aparecimento (TApP) e de mortalidade (TMoP) de perfilhos, o índice de estabilidade (IE) e a densidade populacional de perfilhos. A maior TApP no dossel sob IL de 95% ocorreu no Verão 1, em comparação às demais épocas. Nos dosséis manejados com ILmax, a TApP foi superior no Verão 1 e no Outono, quando comparados às outras épocas. No Verão 1 e no Final da Primavera e Verão 2, houve as maiores TMoP para as duas frequências de corte avaliadas. No Outono, a TMoP também foi alta no dossel cortado com ILmáx. O IE foi menor durante o Verão 1 no dossel sob ILmax e com 15cm de resíduo (0,995). Porém, nas demais épocas, os valores de índice de estabilidade foram maiores que uma unidade e não foram influenciados pela frequência e altura pós-corte. A densidade populacional de perfilhos foi menor no Verão 1, em comparação às demais épocas. O capim-piatã pode ser desfolhado com qualquer combinação entre as interceptações de luz, 95% e ILmax, e alturas pós-corte, 15 ou 20cm, sem prejudicar a persistência do pasto.(AU)

The aim of this study was to evaluate the tillering of Brachiaria brizantha cv. Piatã, as a basis for identifying the frequencies and post-cutting heights most suitable for this grass. In a 2 x 2 factorial scheme, combinations between two cut frequencies (95% and maximum light interception, IL max ) and two post-cut heights (15 and 20cm) were studied. The experimental design was in randomized blocks with 3 replicates, totaling 12 experimental units of 14m 2 each. Rates of appearance (TAR) and mortality (TMR) of tillers, the stability index and the population density of tillers were evaluated. The highest TAR in the canopy under 95% IL occurred in Summer 1, in comparison to the other seasons. In the canopies managed with IL max , TAR was higher in summer 1 and in autumn, when compared to other seasons. In summer 1 and at the end of spring and summer 2, there were the highest TMR for the two cutoff frequencies evaluated. In autumn, TMR was also high in the canopy cut with IL max . IE was lower during summer 1 in the canopy under IL max and 15cm of residue (0.995). However, at other times, stability index values were greater than one unit and were not influenced by post-cut frequency and height. The population density of tillers was lower in Summer 1, when compared to the other seasons. The piata grass may be defoliated with any combination of light intercepts, 95% and ILmax, and post-cut heights, 15 or 20cm, without impairing the persistence of pasture.(AU)

Tillering dynamics of Alexandergrass pasture under nitrogen fertilization / Dinâmica do perfilhamento da pastagem de Papuã sob fertilização nitrogenada

This study was carried out to evaluate the effect of nitrogen fertilization on tillering dynamics of Alexandergrass (Urochloa plantaginea (Link) Hitch) grazed by beef heifers in a rotational stocking grazing method. The experiment was conducted in a completely randomized design following a repeated measure arrangement, three levels of nitrogen (Zero, 150 and 300kg ha-1) and two area repetition. The classification of tillers into categories (basal and axillary) showed a greater number of basal tillers, due to their higher appearance rate, in the absence of nitrogen fertilization. Nitrogen fertilization promoted higher axillary tiller density. The use of nitrogen promotes the renewal of axillary tillers of Alexandergrass, without compromising the stability of the tiller population.(AU)

Esse estudo foi conduzido para avaliar o efeito da fertilização nitrogenada no perfilhamento do Papuã (Urochloa plantaginea (Link) Hitch) pastejado por novilhas de corte em um método de lotação rotacionada. O delineamento foi inteiramente casualizado com arranjo de medidas repetidas, três níveis de nitrogênio (Zero, 150 e 300kg ha -1 ) e duas repetições de área. A classificação dos perfilhos em categorias (basais e axilares) mostrou um maior número de perfilhos basais, devido à sua maior taxa de aparecimento, na ausência de adubação nitrogenada. A fertilização nitrogenada promoveu maior densidade de perfilhos axilares. O uso de nitrogênio promove renovação dos perfilhos axilares no Papuã, sem comprometer a estabilidade da população de plantas.(AU)

Assessment of waterlogging induced physio-biochemical changes in sugarcane varieties and its association with waterlogging tolerance

Aim: The aim of the present investigation was to study the effect of waterlogging on growth and physiological behaviour of sugarcane varieties, and to evaluate these in relation to waterlogging tolerance to identify reliable physiological parameters for screening sugarcane genotypes for waterlogging tolerance.. Methodology: Ten sugarcane varieties including four tolerant and one sensitive were planted under waterlogged and non waterlogged (control) conditions. Waterlogging was imposed for 70 days at the crop age of 120 days, thereafter water was completely drained. Based on relative cane weight (% waterlogged/control), the ranking of varieties was done for waterlogging tolerance. Changes in cane weight, stalk growth rate, internode length, chlorophyll stability index and antioxidant enzyme activity were measured at the end of waterlogging. Leaf samples were analysed for nitrogen, phosphorus and potassium content. Correlation between waterlogging tolerance and different traits was assessed. Results: Based on relative cane weight (% waterlogged/control), CoLk 94184 was found to be the most waterlogging tolerant variety while CoJ 64 the most sensitive. Waterlogging remarkably reduced stalk growth rate and a significant positive correlation was found between waterlogging tolerance and stalk growth rate during waterlogging. The average internode length of sugarcane varieties increased by 11% in waterlogging as compared to control. Tolerant varieties had high chlorophyll stability index than sensitive one showing that tolerant varieties had less chlorosis in waterlogging. Waterlogging caused a significant increase in antioxidant enzyme activity of catalase, peroxidase and superoxide dismutase, however these increase were higher in tolerant varieties. Waterlogging induced severe deficiencies of N, P and K in sugarcane; the leaf N and K concentration were below critical deficiency level. A strong positive correlation was found between leaf K content and waterlogging tolerance. Interpretation: Stalk growth rate, chlorophyll stability index and leaf potassium concentration during waterlogging were identified as efficient physiological traits for screening the sugarcane varieties for waterlogging tolerance.

Accurate measurements of liver stiffness using shear wave elastography in children and young adults and the role of the stability index

PURPOSE: The purpose of this study was to evaluate the usefulness of the stability index (SI) in liver stiffness measurements using shear wave elastography (SWE) in children. METHODS: A total of 29 children and young adults (mean age, 16.1 years; range, 8 to 28 years; 11 boys and 18 girls) who underwent liver stiffness measurements using SWE under free-breathing and breath-holding conditions were included in our study. Ten SWE measurements were acquired in each of four groups: free-breathing and breath-holding, and with and without using the SI. The failure rate of acquisition of SI values over 90% was calculated in each group. To evaluate variability in the SWE measurements, the standard deviation, coefficient of variation, and percentage of unreliable measurements were compared. Intraobserver agreement and the optimal minimal number of measurements were calculated using intraclass correlation coefficients. RESULTS: A failure to acquire SI values over 90% was observed in 17% of the scans in the free-breathing group and in 7% of the scans in the breath-holding group. In both groups, utilizing the SI led to a significantly lower standard deviation and coefficient of variation. When using the SI, the percentage of unreliable measurements decreased from 16.7% to 8.3% in the free-breathing group and 14.8% to 0% in the breath-holding group. With the use of the SI, intraobserver agreement increased and the optimal minimal number of repeated measurements decreased in both the free-breathing and breath-holding groups. CONCLUSION: Utilization of the SI in the measurement of liver SWE in children reduced measurement variability and increased reliability in both free-breathing and breath-holding conditions.

Tiller density and tillering on Brachiaria brizantha cv. Marandu pastures inoculated with Azospirillum brasilense / Densidade populacional e perfilhamento em pastagens de Brachiaria brizantha cv. Marandu inoculada com Azospirillum brasilense

The objective of this study is to verify the population density and the dynamics of tillering in the Marandu palisade grass sward subjected to nitrogen (N) fertilization strategies, characterized by the N supply via urea or bacterial inoculant (Azospirillum brasilense). The treatments comprised of four nitrogen fertilization strategies: (A) Without fertilization, (B) 80 kg N/ha, (C) inoculant (A. brasilense), and (D) 80 kg N/ha + inoculant, distributed in a randomized complete block design, with three replications. The nitrogen supply strategies were evaluated during six periods: October, November, and December (2012) as well as January, March, and April (2013). The nitrogen dose or inoculant had no effect on the tiller appearance rate (TAR), tiller mortality rate (TMR), tiller survival rate (TSR), or tiller population density (TPD). However, these variables were influenced by the season. The TAR and TSR were higher at the beginning of the experimental period (October) and lower towards the end of the period (March-April), whereas, TMR and TPD exhibited the opposite behavior, with lower values in October and higher from January onward. Neither the nitrogen nor the inoculant influenced the population dynamics of the tillers in Marandu palisade grass.(AU)

Objetivou-se com este estudo verificar a densidade populacional e a dinâmica do perfilhamento em dosséis de capim Marandu submetidos a estratégias de adubação nitrogenada, caracterizadas pelo fornecimento de N via ureia ou inoculante (Azospirillum brasilense). Os tratamentos foram quatro estratégias de adubação nitrogenada: sem fertilização, 80kg N/ha, inoculante (A. brasilense) e 80kg N/ha + inoculante, distribuídos em um delineamento de blocos completos ao acaso, com três repetições por tratamento. As estratégias de aporte nitrogenado foram avaliadas em seis épocas: outubro, novembro e dezembro de 2012; e janeiro, março e abril de 2013. Não foi verificada influência da dose de nitrogênio ou do inoculante sobre a taxa de aparecimento (TAP), a taxa de mortalidade (TMP), a taxa de sobrevivência (TSP) e a densidade populacional de perfilhos (DPP). No entanto, essas variáveis foram influenciadas pela época do ano. A TAP e a TSP apresentaram maiores valores no início do período experimental (outubro) e menor valor ao final do período (março a abril). A TMP e a DPP expressaram respostas opostas, com menores valores em outubro e maiores a partir de janeiro. Não houve influência do nitrogênio e do inoculante sobre a dinâmica populacional de perfilhos em capim Marandu.(AU)

Expression analysis of bZIP transcription factor encoding genes in response to water deficit stress in rice.

In plants, basic region/leucine zipper motif (bZIP) transcription factors regulate several developmental processes and activate genes in response to biotic and abiotic stresses. Role of stress responsive bZIP transcription factors was studied in paddy in relation to different stages of development and water deficit stress (WDS) in a drought tolerant cultivar N22 and susceptible IR 64. Further, relative water content (RWC), membrane stability index (MSI) and abscisic acid (ABA) content were measured as indices of WDS at different stages of development and levels of stress. Expression of stress responsive bZIP transcription factors was directly correlated to developmental stage and WDS and indirectly to RWC, MSI and ABA content.

Tillering dynamics in massai grass fertilized with nitrogen and grazed by sheep / Dinâmica de perfilhamento em capim-massai adubado com nitrogênio e pastejado por ovinos

To evaluate the tillering dynamics of massai grass under rotational sheep stocking and fertilized with nitrogen (control - 0; 400; 800 and 1200 kg ha-1 year-1), this study was carried out, in a completely randomized design with repeated measures over time. The mob-grazing technique was applied to perform the grazing by employing groups of animals for rapid defoliation. The tiller appearance, survival and mortality rates, tiller biomass, and green/dead tillers ratio, have presented increase responses to nitrogen levels, with the three rates and the tiller biomass varying between evaluation periods. There was a quadratic response for the tiller flowering rate, population density of vegetative and reproductive tillers, reaching maximum values (0.051 tiller 100 tiller-1 day-1; 4,818 and 35 tillers m-2, respectively) under the nitrogen levels of 613.5; 993.5 and 623.9 kg ha-1 year-1, respectively. For the tiller flowering rate and population density of reproductive tillers, it was verified a fluctuation between periods. The nitrogen fertilization promotes positive changes in tillering dynamics of massai grass, allowing the use of up to 800 kg ha-1 year-1 for maintaining the pasture stability. The tillering demography of the forage had varied little between assessment periods.

Objetivou-se avaliar a dinâmica de perfilhamento do capim-massai sob lotação rotativa com ovinos e adubado com nitrogênio (controle - 0; 400; 800 e 1200 kg ha-1 ano-1), em um delineamento inteiramente casualizado com medidas repetidas no tempo. A técnica de "mob-grazing" foi usada para a realização dos pastejos, empregando-se grupos de animais para desfolhações rápidas. As taxas de aparecimento, sobrevivência e mortalidade de perfilhos, biomassa do perfilho e relação perfilhos vegetativos/perfilhos mortos responderam crescentemente às doses de nitrogênio, com as três taxas e a biomassa do perfilho variando entre os períodos de avaliação. Constatou-se resposta quadrática para a taxa de florescimento de perfilhos, densidade populacional de perfilhos vegetativos e densidade populacional de perfilhos reprodutivos, alcançando valores máximos (0,051 perf 100 perf-1 dia-1; 4818 e 35 perfilhos m-2, respectivamente) nas doses de nitrogênio de 613,5; 993,5 e 623,9 kg ha-1 ano-1, respectivamente. Para a taxa de florescimento e densidade populacional de perfilhos reprodutivos, verificou-se oscilação entre os períodos de avaliação. A adubação nitrogenada proporciona mudanças positivas na dinâmica de perfilhamento do capim-massai, podendo-se utilizar uma dose de nitrogênio de até 800 kg ha-1 ano-1 para a manutenção da estabilidade do pasto. A demografia do perfilhamento da referida forrageira oscila entre os períodos de avaliação.

Artificial disc and vertebra system: a novel motion preservation device for cervical spinal disease after vertebral corpectomy

OBJECTIVE: To determine the range of motion and stability of the human cadaveric cervical spine after the implantation of a novel artificial disc and vertebra system by comparing an intact group and a fusion group. METHODS: Biomechanical tests were conducted on 18 human cadaveric cervical specimens. The range of motion and the stability index range of motion were measured to study the function and stability of the artificial disc and vertebra system of the intact group compared with the fusion group. RESULTS: In all cases, the artificial disc and vertebra system maintained intervertebral motion and reestablished vertebral height at the operative level. After its implantation, there was no significant difference in the range of motion (ROM) of C3-7 in all directions in the non-fusion group compared with the intact group (p>0.05), but significant differences were detected in flexion, extension and axial rotation compared with the fusion group (p<0.05). The ROM of adjacent segments (C3-4, C6-7) of the non-fusion group decreased significantly in some directions compared with the fusion group (p<0.05). Significant differences in the C4-6 ROM in some directions were detected between the non-fusion group and the intact group. In the fusion group, the C4-6 ROM in all directions decreased significantly compared with the intact and non-fusion groups (p<0.01). The stability index ROM (SI-ROM) of some directions was negative in the non-fusion group, and a significant difference in SI-ROM was only found in the C4-6 segment of the non-fusion group compared with the fusion group. CONCLUSION: An artificial disc and vertebra system could restore vertebral height and preserve the dynamic function of the surgical area and could theoretically reduce the risk of adjacent segment degeneration compared with the anterior fusion procedure. However, our results should be considered with caution because of the low power of the study. The use of a larger ...

Biomechanical comparison between artificial atlanto-odontoid joint replacament and Magerl transarticular screw fixation / 中国矫形外科杂志

[Objective]To determine the initial stability and function of a new artificial joint in a cadaveric cervical spine model by comparing it with a conventional method. [Methods]Twelve fresh human cadaveric cervical spines(C0~3) were randomly divided into 2 groups: group 1,resection of the odontoid with artificial atlanto-odontoid joint(AAOJ),and group 2,resection of the odontoid with Magerl atlas and axis by transarticular screw fixation(Magerl).For each specimen,the intact and resection of the odontoid underwent a flexibility test firstly,followed by the instrumented construct.Rotational angles of the C0~3 segment were measured to study the immediate stability and function of resection of the odontoid and AAOJ,compared with the intact and resection of the odontoid and Magerl.[Results]Compared to the intact state,resection of the odontoid and AAOJ resulted in a significant decrease in the range of motion(ROM) and neutral zone(NZ) during flexion,extension,and lateral bending(P0.05).Compared to the intact state,resection of the odontoid and Magerl resulted in a significant decrease in the range of motion(ROM) and neutral zone(NZ) during all 6 degrees of freedom(P0.05).[Conclusion]A new type of artificial atlanto-odontoid joint has been designed for correcting atlantoaxial instability resulted from C1、2 anterior decompression procedures.It can restore,to a great extent,the C1、2 axial rotation that is lost during current stabilization procedures.