ABSTRACT
Objective@#To evaluate the bone repair effect of 3D-printed magnesium (Mg)-loaded polycaprolactone (PCL) scaffolds in a rat skull defect model.@*Methods@#PCL scaffolds mixed with Mg microparticles were prepared by using 3D printing technology, as were pure PCL scaffolds. The surface morphologies of the two scaffolds were observed by scanning electron microscopy (SEM), and the surface elemental composition was analyzed via energy dispersive spectroscopy (EDS). The physical properties of the scaffolds were characterized through contact angle measurements and an electronic universal testing machine. This study has been reviewed and approved by the Ethics Committee. A critical size defect model was established in the skull of 15 Sprague-Dawley (SD) rats, which were divided into the PCL group, PCL-Mg group, and untreated group, with 5 rats in each group. Micro-CT scanning was performed to detect and analyze skull defect healing at 4 and 8 weeks after surgery, and samples from the skull defect area and major organs of the rats were obtained for histological staining at 8 weeks after surgery.@*Results@#The scaffolds had a pore size of (480 ± 25) μm, a fiber diameter of (300 ± 25) μm, and a porosity of approximately 66%. The PCL-Mg scaffolds contained 1.0 At% Mg, indicating successful incorporation of Mg microparticles. The contact angle of the PCL-Mg scaffolds was 68.97° ± 1.39°, indicating improved wettability compared to that of pure PCL scaffolds. Additionally, compared with that of pure PCL scaffolds, the compressive modulus of the PCL-Mg scaffolds was (57.37 ± 8.33) MPa, demonstrating enhanced strength. The PCL-Mg group exhibited the best bone formation behavior in the skull defect area compared with the control group and PCL group at 4 and 8 weeks after surgery. Moreover, quantitative parameters, such as bone volume (BV), bone volume/total volume (BV/TV), bone surface (BS), bone surface/total volume (BS/TV), trabecular thickness (Tb.Th), trabecular number (Tb.N) and bone mineral density (BMD), of skull defects were better than those in the other groups, indicating the best bone regeneration effect. H&E, Goldner, and VG staining revealed more mineralized new bone formation in the PCL-Mg group than in the other groups, and H&E staining of the major organs revealed good biosafety of the material.@*Conclusion@#PCL-Mg scaffolds can promote the repair of bone defects and have clinical potential as a new scaffold material for the repair of maxillofacial bone defects.
ABSTRACT
@#AIM: To analyze the difference of macular retinal thickness between diabetic patients without apparent visual loss and normal subjects.<p>METHODS: Totally 40 cases(79 eyes)with type 2 diabetes without significant decrease of visual acuity(best corrected visual acuity, BCVA ≥0.8)in our hospital from April, 2018 to June, 2019 were enrolled as observation group and 64 cases(119 eyes)normal persons were enrolled as control group. The average retinal thickness in nine areas of macula, central retinal thickness(CRT), average retinal thickness(ART)and total volume(TV)of all patients were determined by optical coherence tomography(OCT), and the difference of average retinal thickness in nine areas of macula, CRT, ART and TV among them were compared.<p>RESULTS: The CRT, ART and TV(193.99±14.58μm, 291.07±12.24μm, 8.22±0.35mm3)in the observation group were significantly higher than those in the control group(187.38±12.24μm, 280.54±8.71μm, 7.92±0.25mm3), and the average retinal thickness in nine areas of macula in the observation group was significantly higher than that in the control group(<i>P</i><0.05).<p>CONCLUSION: Compared with normal persons, macular retinal thickness and TV are significantly thickened in early stage of type 2 diabetes.
ABSTRACT
O objetivo do presente estudo foi verificar o efeito da intensidade do exercício de força sobre a percepção de dor muscular de início tardio (DMIT). A fim de investigar a hipótese que a intensidade determina o nível de DMIT, foram selecionados 40 homens saudáveis, iniciantes no treinamento de força, que, posteriormente, foram submetidos a duas sessões de treinamento realizadas com intensidades distintas (50%-1RM (n=20) e 75%-1RM (n=20)). A DMIT foi analisada por meio da escala analógica visual, 24, 48 e 72h após cada sessão de treinamento. A DMIT apresentou aumento significante em ambas as sessões (50%-1RM e 75%-1RM) (p<0,05), atingindo o pico em 48h (p<0,05). Entretanto, a DMIT não apresentou diferença entre as sessões (50%-1RM vs. 75%-1RM) (p>0,05). Os resultados desse estudo sugerem que a intensidade não parece ser um fator determinante para a magnitude da DMIT, quando o volume total de carga levantada na sessão de treinamento é equalizado.
The aim of the study was to assess the effect of resistance exercise intensity on the perceived DOMS. In order to investigate the hypothesis that the intensity determines the magnitude of DOMS, 40 healthy, untrained men were subjected to two bouts of resistance exercise performed at different intensities (50%-1RM (n=20) and 75%-1RM (n=20)). DOMS was assessed using visual analogue scale, 24, 48 and 72 hours after each training bout. DOMS increased after both exercise bouts (50%-1RM and 75%-1RM) (p<0.05), peaking at 48 hours (p<0.05). However, DOMS did not differ between exercise sessions (50%-1RM and 75%-1RM) (p>0.05). The results suggested that the intensity does not seem to influence the magnitude of DOMS when the total volume of load lifted during the exercise bout is equalized.
ABSTRACT
A ordem dos exercícios refere-se à sequência de execução durante uma sessão de treinamento. Evidências demonstram que essa ordem pode afetar o número de repetições realizadas nos exercícios. A percepção subjetiva de esforço (PSE), assim como o número de repetições realizadas, depende da sobrecarga utilizada. Assim, alterações no número de repetições podem afetar a PSE. O volume total de trabalho (VTT) influencia nas adaptações crônicas ao treinamento e também pode ser afetado pela ordem dos exercícios. O objetivo foi verificar o efeito da ordem dos exercícios para membros inferiores no número de repetições realizadas, na PSE e no VTT. Doze homens treinados (19,3 ± 2,1 anos, 71,1 ± 9,8 kg, 172,4 ± 6,1 cm, 23,3 ± 11,5 meses/treino) realizaram duas sessões com os exercícios "leg-press" (L), mesa flexora (F) e cadeira extensora (E) em diferentes ordens (LFE ou EFL). Foram utilizados testes t de "Student" pareados com ajuste de Bonferroni para comparações múltiplas. O número de repetições em L e E diminuiu quando realizados no final da sessão. As repetições realizadas em F diminuíram na LFE. A PSE de E foi maior quando realizada no final da sessão, porém de L e de F não foram afetadas pelas diferentes ordens. O volume de trabalho total de LFE foi maior. Em conclusão, a ordem dos exercícios envolvendo membros inferiores afeta o número de repetições e a PSE de um exercício além do VTT, ressaltando a importância da ordem dos exercícios como uma importante variável na prescrição do treinamento.
The order of exercises refers to the sequence during a training bout. Some evidence shows that the number of repetitions may be affected by the order of exercises. Both the number of repetitions and the rate of perceived effort (PSE) are influenced by exercise load. Thus, changes in the number of repetitions may affect PSE. Additionally, total work volume influences long term training adaptations and can be affected by the order of exercises. The aim of this study was to evaluate the effect of order of lower limb exercises on the number of repetitions, RPE and total work volume. Twelve resistance trained male (19.3 ± 2.1 years, 71.1 ± 9.8 kg, 172.4 ± 6.1 cm, 23.3 ± 11.5 months of training) performed leg-press (L), leg extension (E) and leg curl (F) exercises, in different orders (LFE or EFL). Number of repetitions, PSE and total work volume were compared by paired t-test with Bonferroni adjustment. Number of repetitions on both L and E decreased when they were performed last in the bout. The number of repetitions on F also decreased, when F was preceded by L. PSE for E was greater when performed at the end of the bout. However, PSE after L and F were not affected by the order. Total work volume was greater in LFE. In conclusion, the order of lower limb exercises affects the number of repetitions, PSE and total work performed, supporting the importance of the order of exercises as an important variable in training prescription.
Subject(s)
Humans , Male , Young Adult , Exercise , Hypertrophy , Lower Extremity , Physical ExertionABSTRACT
O trabalho foi realizado em propriedades rurais, localizadas nas sub-bacias hidrográficas dos Ribeirões Santa Cruz e Água Limpa, as quais pertencem à bacia do Rio Grande, Lavras, MG, com o objetivo de avaliar e relacionar os atributos físicos do solo com a produtividade das pastagens. Não houve diferenças significativas entre os valores de densidade do solo, porosidade total, micro e macroporosidade nos solos sob os diferentes tipos de pastagens, assim como entre as diferentes profundidades coletadas. O pisoteio animal nestas pastagens, na lotação observada e em sistema de pastejo contínuo, não levou, na camada de 0-10 cm, à obtenção de maiores valores para densidade do solo em relação a subsuperfície. Pela correlação canônica, verificou-se que as produtividades das pastagens mostram associação na sua sensibilidade relacionada aos atributos físicos do solo avaliados.
The work was performed in agricultural properties, located on the hydrographic sub-basins of Santa Cruz and Água Limpa streams, belonging to the Rio Grande basin, Lavras, MG, with the aim of evaluating and relating soil physical attributes with pastures productivity. No differences were observed among bulk density, total porosity, micro and macro-porosity values in soils under different pastures, as well as under different soil samples depths. The animal trampling on these pastures, considering the amount of animals observed in the area and the continuous system of pasture management, did not translate to higher values of bulk density, at 0-10cm depth, and at the subsurface. Through canonical correlation one verified that pastures productivity showed association in its sensibility related to soils physical attributes.