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Objective To examine the effects of shoe cushioning on impact characteristics, kinematics and dynamics of lower extremities before and after neuromuscular fatigue during drop landing. Methods Fifteen trained male athletes were required to execute three successful trials of drop landing from a 60-cm platform before and after fatigue protocol. The impact force, loading rate, lower extremity kinematics, joint moment, joint stiffness were compared. Results Before fatigue, highly-cushioned shoes reduced the loading rate at heel before fatigue, and the time to peak loading rate of heel was significantly shorter than that of control shoes. After fatigue, highly-cushioned shoes significantly reduced the peak impact force and loading rate at heel, loading rate at forefoot. Meanwhile the time to peak impact force and peak loading rate at heel were significantly longer, and the contact and minimum angle of ankle were significantly greater. No significant changes were found in lower extremity stiffness, peak moment and joint stiffness of ankle. Conclusions In the situation where neuromuscular activity is reduced, highly-cushioned shoes can effectively attenuate the impact, thereby helping to avoid or reduce the potential impact damage after fatigue.
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RESUMO O estudo sobre reatores anaeróbios em laboratório prioriza o controle de determinados parâmetros que são de difícil controle em campo, o que dificulta o processo de scale-up. Entre os parâmetros está a carga orgânica volumétrica (COV). No caso do dejeto suíno, esse parâmetro pode sofrer alterações diárias em função das condições climáticas, das mudanças no manejo, da alimentação dos animais, entre outros. A fim de verificar o impacto dessa variação na produtividade de biogás, foi analisado o comportamento de um reator anaeróbio de mistura completa (CSTR) em dois diferentes tempos de retenção hidráulica (TRHs) - 20 e 30 dias - durante um período total de 180 dias. Os resultados demonstraram que a elevação da COV resulta em piora da eficiência de tratamento, bem como na produção de biogás. O ensaio com TRH de 20 dias obteve uma melhor resposta às alterações de carga orgânica.
ABSTRACT The study of anaerobic digesters at laboratory focuses on the control of certain parameters that are not so easy to control in the field, which makes it difficult to process scale-up. One example is the Organic Loading Rate. To swine manure, this parameter can change daily due to weather conditions, management practices, feeding and others. In order to verify the impact of this fluctuation on biogas yield, the behavior of a CSTR reactor was analyzed in two different Hydraulic Retention Times (20 and 30 days) for a total period of 180 days. The result demonstrated that the increase of OLR result in a decrease of treatment efficiency as well as biogas yields. The study with HRT of 20 days had a better response to changes in organic load.
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Objective To evaluate the effects of chitosan microspheres as the ball wall,pre pared by emulsion cross-linked VEGF chitosan microspheres.Methods 1 ％ chitosan aqueous solution as the aqueous solution and genipin as a cross-linking agent were used to detect the drug loading rate and cumulative release rate of drug-loaded microspheres by ELISA.Results VEGF chitosan microsphere size was about 5.25-20.34 μm;electron microscopy showed that microspheres surface was smooth,decentralized,and had small adhesions each other.The highest encapsulation efficiency was (56.33±3.42) ％ and the highest drug loading rate was (18.75±0.32) ng/mg.In vitro release experiments showed that the concentration of VEGF increased gradually with the passage of time.The release rate of microspheres was (32.32±2.31)％ on the first day and (86.42±1.68)％ on the 21st day.The cumulative release rate was 88.7％.Conclusions Genipin can be used to prepare chitosan microspheres loaded with different concentrations of VEGF with good performance and simple preparation process.The drug-loading rate and entrapment efficiency of the obtained microspheres are both high.
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Objective: The preparation process of curcumin-loaded TPGS/F127/P123 mixed micelles was optimized with uniform design method to improve the poor solubility of curcumin in water, aiming to increase entrapment efficiency (EE), drug-loading (DL), and reduce the precipitated drug (PD). Methods: Curcumin-loaded TPGS/F127/P123 mixed micelles were prepared by thin-film hydration method with modification. Before using the uniform design, a number of preliminary experiments were conducted to identify the controlled factors such as the amount of curcumin, the dosage of TPGS, and the ratio of F127/P123. The formulation was operated by uniform design of three factors and seven levels, and its results were fitted by polynomial linear equation, the response surface, and the contour line in order to choose and verify the optimal preparation process. Results: In the optimum formulation, the dosage of curcumin was 14.0 mg, TPGS 150.0 mg, and the ratio of F127/P123 was 68: 32. The solubility of optimum formulation was (3.47 ± 0.14) mg/mL, EE (87.15 ± 4.39)%, DL (4.70 ± 0.17)%, and PD (0.33 ± 0.12)% in 48 h. Conclusion: The solubility of curcumin in TPGS/F127/P123 mixed micelles was improved after the optimization of the uniform design method, and EE and DL were also improved.
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Objective: To prepare GEN-VES-TPGS nano-micelles and improve the oral bioavailability of genistein (GEN). Methods: GEN-VES-TPGS nano-micelles, made by film hydration, were evaluated with particle size, entrapment efficiency, and drug-loading as indexes. Single factor experiment was used to optimize the formulation and productive technology, including dosages of TPGS, VES, GEN, hydration volume, temperature, and time. Morphology of nano-micelles, release rate in vitro, and pharmacokinetics in rat were investigated. Results: The results showed GEN-VES-TPGS nano-micelles presented with good clarity, appropriate particle diameter (43.50 ± 1.65) nm, negative charge, when the dosages of TPGS, VES, GEN were 200, 30, and 6 mg, respectively. Meanwhile, a condition of 15 mL, 50 ℃ at 3 h to hydrate was necessary to prepare. In this setting, the encapsulation efficiency of the nano-micelles was (98.99 ± 0.69)% and drug-loading rate was (2.57 ± 0.04)%. The pharmacokinetic results in rats showed the oral bioavailability of GEN-VES-TPGS nano-micelles was 162.96% of the GEN APIs. Conclusion: The prepared GEN-VES-TPGS nano-micelles have small particle size and good stability, and increase the oral bioavailability of GEN evidently.
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ABSTRACT The main objective of this study was to evaluate the anaerobic conversion of vinasse into biomethane with gradual increase in organic loading rate (OLR) in two upflow anaerobic sludge blanket (UASB) reactors, R1 and R2, with volumes of 40.5 and 21.5 L in the mesophilic temperature range. The UASB reactors were operated for 230 days with a hydraulic detection time (HDT) of 2.8 d (R1) and 2.8-1.8 d (R2). The OLR values applied in the reactors were 0.2-7.5 g totalCOD (L d)−1 in R1 and 0.2-11.5 g totalCOD (L d)−1 in R2. The average total chemical oxygen demand (totalCOD) removal efficiencies ranged from 49% to 82% and the average conversion efficiencies of the removed totalCOD into methane were 48-58% in R1 and 39-65% in R2. The effluent recirculation was used for an OLR above 6 g totalCOD (L d)−1 in R1 and 8 gtotalCOD (L d)−1 in R2 and was able to maintain the pH of the influent in R1 and R2 in the range from 6.5 to 6.8. However, this caused a decrease for 53-39% in the conversion efficiency of the removed totalCOD into methane in R2 because of the increase in the recalcitrant COD in the influent. The largest methane yield values were 0.181 and 0.185 (L) CH4 (gtotal COD removed)−1 in R1 and R2, respectively. These values were attained after 140 days of operation with an OLR of 5.0-7.5 g totalCOD (L d)−1 and total COD removal efficiencies around 70 and 80%.
Subject(s)
Sewage/microbiology , Fermentation , Methane/biosynthesis , Phosphorus/metabolism , Bioreactors , Volatile Organic Compounds , Biological Oxygen Demand Analysis , Hydrogen-Ion Concentration , Anaerobiosis , Nitrogen/metabolismABSTRACT
RESUMO Esta pesquisa comparou o desempenho de um digestor anaeróbio de lodo sob diferentes estratégias operacionais. Foi avaliada a influência do aumento da carga orgânica volumétrica (COV) (OP I) e o efeito da redução do tempo de detenção hidráulica (TDH) (OP II e OP III) no processo anaeróbio. As cargas aplicadas variaram entre 0,5 e 4,5 kgSV.m-3.d-1 e o TDH foi reduzido de 15 a 5 dias. Produção de gás metano, degradação do material orgânico e a diversidade microbiana foram utilizadas para medição e comparação do desempenho do processo. Foram necessários períodos de aclimatação a cada nova COV aplicada o que levou às instabilidades na remoção de SV e DQO do lodo. A operação com TDH entre 7 e 5 dias apresentou as maiores eficiências de remoção de SV, superiores a 70%, o que influenciou positivamente na estabilidade do processo. As COV aplicadas de 2,5 e 3,5 kgSV.m-3.d-1 resultaram nas maiores produções de metano durante a OP I. Para TDH inferiores a sete dias a produção de CH4 foi prejudicada apesar da existência de microorganismos metanogênicos atuantes no digestor. Comparativamente, a estratégia de redução do TDH resultou em um melhor desempenho do sistema que a fixação da COV. Quanto menor o TDH aplicado, melhor os resultados obtidos na operação do digestor, sugerindo que a eficiência do processo é otimizada em sistemas de alta carga com operação em baixos tempos de detenção hidráulica.
ABSTRACT This study compared the performance of a pilot anaerobic sludge digester under different operating strategies. The influence of increasing organic loading rate - OLR (OP I) and the effect of hydraulic retention time - HRT reduction (OP II and OP III) in anaerobic process were evaluated. The applied loads ranged between 0.5 and 4.5 kgSV.m-3.d-1; HRT was reduced from 15 to 5 days. Production of methane, organic matter degradation and microbial diversity were used to measure and compare the system´s performance. Acclimation periods were taken for each new OLR applied, leading to instabilities in sludge VS and COD removals. The experimental time with HRT between 7 and 5 days showed the highest VS efficiency removals (higher than 70%), which positively influenced process stability. The applied OLR of 2.5 and 3.5 kgVS.m-3.d-1 resulted in higher yields of methane during OP I. CH4 production showed impaired with HRT lower than 7 days, although it was observed active methanogenic microorganisms in the digester. Comparatively, HRT reduction resulted in a better system performance than the increasing OLR approach. The lower HRT applied, the better the results obtained in the operation of the digester, suggesting that the process efficiency is optimized with high load operation at low hydraulic retention times.
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Objective To study the anisotropic mechanical properties of the thoracic aorta in porcine. Methods Twenty-one porcine thoracic aortas were collected and categorized into three groups. The aortas were then cut through in their axial directions and expanded into two dimensional planes. Then, by setting the length direction of the planar aortas (i.e., axial directions of the aortas) as 0°, each planar aorta was counterclockwisely cut into 8 samples with orientation of 30°, 45°, 60°, 90°, 120°, 135°, 150° and 180°, respectively. Finally, the uniaxial tensile tests were applied on three groups of samples at the loading rates of 1, 5 and 10 mm/min, respectively, to obtain the elastic modulus and ultimate stress of the aorta in different directions and at different loading rates. Results The stress-strain curves exhibited different viscoelastic behaviors. With the increase of sample orientations, the elastic modulus gradually increased from 30°, reached the maximum value at 90°, and then gradually decreased till 180°. The variation trend of ultimate stress was similar to that of elastic modulus. Moreover, different loading rates showed a significant influence on the results of elastic modulus and ultimate stress, but a weak influence on the anisotropic degree. Conclusions The porcine thoracic aorta is highly anisotropic. This research finding provides parameter references for assignment of material properties in finite element modeling, and is significant for understanding biomechanical properties of the arteries.
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A poluição da água e do solo causada pela suinocultura provoca impactos ambientais severos nas regiões produtoras. Uma alternativa eficiente para atenuar esse problema pode ser a utilização de reatores anaeróbios de alta taxa. Neste trabalho, avaliou-se o efeito das águas residuárias de suinocultura com concentrações de sólidos suspensos totais em torno de 6.000 mg.L−1 no desempenho do reator anaeróbio compartimentado, com três câmaras. O volume da primeira câmara foi de 210 L e da segunda e terceira de 160 L. O reator anaeróbio compartimentado foi submetido a tempos de detenção hidráulica de 56, 28 e 18 horas e a cargas orgânicas volumétricas de 5,0 a 10,1 g DQOtotal (L.d)−1. As maiores remoções de demanda química de oxigênio total, de 42 a 68%, e das produções volumétricas de metano, de 0,261 a 0,454 L CH4 (L reator d)−1, ocorreram na segunda câmara.
Water and soil pollution caused by the waste from the swine production causes severe environmental impacts in producing areas. An efficient alternative to reduce these impacts can be the use of high-rate anaerobic reactors. In this work, it was evaluated the effect of the swine wastewater with total suspended solids concentrations around 6.000 mg.L−1 in the anaerobic baffled reactor with three compartments. The volume of the first compartment was 210 L and of the second and third ones of 160 L. The anaerobic baffled reactor was submitted at hydraulic detention times of 56, 28 and 18 hours and to organic load rates of 5.0 to 10.1 g total COD (L.d)−1. The highest total COD removals, of 42 to 68%, and volumetric methane productions, of 0.261 to 0.454 L CH4 (L reactor d)−1, occurred in the second compartment.
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OBJECTIVE: To study the drug release and cytotoxicity in vitro of 5-fluorouracil (5-Fu)-loaded porous metal-organic frameworks of MIL-53. METHODS: MIL-53 was hydrothermally synthesized, and the synthetic MIL-53 was characterized by TEM, XRD, IR and TG. 5-Fu was loaded into MIL-53, and the release pattern and cytotoxicity were investigated. RESULTS: The structure of MIL-53 was confirmed. The diameter of MIL-53 was at nanometer level and MIL-53 displayed better thermo-stabilization. The highest drug loading rate was 0.431 g · g-1 MIL-53 for 5-Fu. The drug release profile of 5-Fu-loaded MIL-53 displayed a clear biphasic release pattern. Cytotoxicity test showed that MIL-53 had good biocompatility at lower concentrations. CONCLUSION: MIL-53 is a promising platform for drug delivery due to its large pore sizes for drug encapsulation and good biocompatility at lower concentrations.
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Objective To investigate the loading rate-dependent property of different layers for articular cartilage by unconfined compression testing on articular cartilage at different loading rates. Methods The non-contact digital image correlation (DIC) technique was applied to investigate the mechanical properties of different layers for fresh pig articular cartilage at different loading rates. Results At constant loading rate, the compressive strain of superficial layer and deep layer was the largest, while that of middle layer was in between under the same compressive stress. The Poisson’s ratio increased from superficial layer to deep layer along with cartilage depth increasing. The stress-strain curves of cartilage were different at different loading rates, indicating that the mechanical properties of cartilage were dependent on the loading rate. The elastic modulus of cartilage increased with loading rates increasing, and the compressive strains of different layers decreased under the same compressive stress with loading rates increasing. Conclusions The compressive strain decreased while the Poisson’s ratio increased from superficial layer to deep layer along the cartilage depth. The mechanical properties of different layers for cartilage were dependent on the loading rate. This study can provide the basis for clinical cartilage disease prevention and treatment, and is important for mechanical function evaluation of artificial cartilage as well.
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Two continuous stirred tank reactors (CSTRs) each fed with palm oil mill effluent (POME), operated at 37ºC and 55ºC, respectively, were investigated for their performance under varies organic loading rates (OLRs). The 37ºC reactor operated successfully at a maximum OLR of 12.25 g[COD]/L/day and a hydraulic retention time (HRT) of 7 days. The 55ºC reactor operated successfully at the higher loading rate of 17.01 g[COD]/L/day and had a HRT of 5 days. The 37ºC reactor achieved a 71.10% reduction of chemical oxygen demand (COD), a biogas production rate of 3.73 L of gas/L[reactor]/day containing 71.04% methane, whereas the 55ºC reactor achieved a 70.32% reduction of COD, a biogas production rate of 4.66 L of gas/L[reactor]/day containing 69.53% methane. An OLR of 9.68 g[COD]/L/day, at a HRT of 7 days, was used to study the effects of changing the temperature by 3ºC increments. The reactor processes were reasonably stable during the increase from 37ºC to 43ºC and the decrease from 55ºC to 43ºC. When the temperature was increased from 37ºC to 46ºC, the total volatile fatty acid (TVFA) concentration and biogas production was 2,059 mg as acetic acid/L and 1.49 L of gas/L[reactor]/day at day 56, respectively. When the temperature was reduced from 55ºC to 40ºC, the TVFA concentration and biogas production was 2,368 mg as acetic acid/L and 2.01 L of gas/L[reactor]/day at day 102, respectively. By first reducing the OLR to 4.20 g[COD]/L/day then slowly increasing the OLR back to 9.68 g[COD]/L/day, both reactors were restored to stable conditions at 49ºC and 37ºC respectively. The initial 37ºC reactor became fully acclimatized at 55ºC with an efficiency similar to that when operated at the initial 37ºC whereas the 55ºC reactor also achieved stability at 37ºC but with a lower efficiency.
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OBJECTIVE:To establish an HPLC method for the determination of the drug loading rate of butyl-5-aminosalicylic acid-pectin conjugate.METHODS:The conjugate was hydrolyzed with base solution and neutralized with acid before being determined by HPLC.Kromasil C18 column was used as chromatographic column with mobile phase consisted of water(containing 0.15% triethylamine and 0.15% acetic acid)-methanol(95∶5,V/V).The detection wavelength was set at 240 nm.RESULTS:The calibration curve of 5-aminosalicylic acid was linear over the range of 1～100 ?g?mL-1(r=0.999 9) at an average recovery of 99.90%.Both intra-day and inter-day RSD were less than 2.25%.The drug loading rate of the conjugate was 12.76 %(n=3).CONCLUSION:The method is simple,rapid,accurate,and suitable for the determination of drug-loading rate of conjugate.