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Volatile fatty acids (VFAs) are intermediates of anaerobic fermentation with high value and wide range of usage. VFA production from vegetable wastes (VW) is an effective way to dispose of wastes and recover resources. The organic...
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Volatile fatty acids (VFAs) are intermediates of anaerobic fermentation with high value and wide range of usage. VFA production from vegetable wastes (VW) is an effective way to dispose of wastes and recover resources. The organic matter composition of the substrate influences VFA yield and distribution, which is related to the separation and purification of the downstream steps and the application of the product Hence, potato peels, carrots, celery, and Chinese cabbage were selected to investigate the effect of VW types on the performance of the VFA production in a batch anaerobic fermentation reactor with continuous stirring at 37 ℃, total solid (TS) of 4.5%. A VFA yield of 452 mg COD/g VS_(feed) (chemical oxygen demand (COD); volatile solids (VS)) was achieved from potato peels, which was 40.1%, 21.5%, and 124.9% higher than that of carrots, celery, and Chinese cabbage, respectively. The rapid acidification of carrots caused a sharp decline in pH and led to inhibition of VFA production. The acidification of celery started slowly, and the yield of hexanoic acid increased rapidly in the later stage of fermentation. The VFA yield of Chinese cabbage was inhibited due to the low initial pH, but the ethanol concentration reached 7577.04 mg COD/L According to the VFA profile, the fermentation of potato peels, carrots, celery, and Chinese cabbage can be classified as propionate-type, butyrate-type, mixed-acid type, and ethanol-acetate type metabolic pathway, respectively. The results of this study suggest that a suitable combination of vegetable waste types is important for selective VFA production.
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Ultrasonic pretreatment combined rumen microorganisms (RM) anaerobic hydrolysis was used as a novel method to boost volatile fatty acids (VFAs) production from lignocellulose waste pulp and paper mill excess sludge (PPES). To inve...
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Ultrasonic pretreatment combined rumen microorganisms (RM) anaerobic hydrolysis was used as a novel method to boost volatile fatty acids (VFAs) production from lignocellulose waste pulp and paper mill excess sludge (PPES). To investigate the effect of ultrasonic on PPES degradation, various ultrasonic power levels and treatment time were used to treat PPES. The findings showed that ultrasonic pretreatment breaks the structure of PPES distinctly and significantly contributes to promoting PPES degradation. Under ultrasonic power level of 540 W and treatment time of 50 min conditions, the production of soluble chemical oxygen demand (SCOD), ammonia nitrogen (NH4+-N), reducing sugar, and soluble protein was 36.9, 16.9, 29.2, and 26.8 times of control-1, respectively. In the following RM anaerobic acidification experiment, VFAs production of PPES after ultrasonic treatment increased by 92 % compared to that of PPES without ultrasonic treatment and were much higher than that of the control-2 group without inoculating RM. During the fermentation stage, the degradation yield of cellulose, hemicellulose and lignin were 40.35 %, 58.35 % and 16.49 %, respectively. These results demonstrated that ultrasonic-RM treatment could improve the efficiency of the anaerobic acidification process and VFAs production and RM had a strong effect on degradation of hemicellulose and cellulose. In addition, Illumina MiSeq sequencing showed that the number of microbial species decreased, and the dominant flora changed.
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Short-chain fatty acids (SCFAs) are the main source of energy for postweaning ruminants, The monocarboxylic acid transporters, MCTI and MCT4, are thought to contribute to the absorption of SCFAs from the surface of the rumen follo...
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Short-chain fatty acids (SCFAs) are the main source of energy for postweaning ruminants, The monocarboxylic acid transporters, MCTI and MCT4, are thought to contribute to the absorption of SCFAs from the surface of the rumen following weaning. The present study measured changes in MCT1 and MCT4 expression in ruminal epithelial cells isolated from male preweaning (22 to 34 d old, = 6) and postweaning (55 to 58 d old, a = 8) calves after euthanasia and sought to examine whether SCFAs stimulate the expression of these transporters. In the current study, cluster of differentiation 147 (CD147) gene expression in the rumen was also investigated since CD147 has been considered to act as ancillary protein for MCT1 and MCT4 to express their correct function. The gene expression levels of MCT1. MCT4, and CD147 in the rumen were found to be significantly higher in postweaning calves than in preweaning calves. Strong MCT1 immunoreactivity was detected in both the stratum basale (SB) and the stratum spinosum (SS) in postweaning ruminal epithelium. Expression of MCTI in preweaning calves was localized to a specific region of the SB and of the SS. MCT4-immunopositive cells were detected in the stratum corneum (SC) of the ruminal epithelium in postweaning calves. However, only a low level of signal was detected in the SC of preweaning animals. Furthermore, in vitro experiments, ruminal epithelial cells were incubated for 24 h with acetate (0.04, 0.4, and 4 mM), propionate (0.2, 2, and 20 mM), butyrate (0.1, 1, and 10 mM), or (3-hydroxybutyrate (BHBA; 0.1, 1, and 10 mM), respectively. Both propionate and butyrate induced an increase in the gene expression levels of MCT4 and CD147, but did not affect MCTI gene expression. There are no significant effects of acetate and BHBA treatment on these gene expressions. Taken together, these results suggest that an increase in MCT4 and CD147 gene expression in the ruminal epithelium of postweaning calves is likely to be due to the effects of propionate and butyrate derived from a solid-based diet, which may contribute to ruminal development following weaning.
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Purpose Many osteoporotic vertebral fractures are not clinically recognized but increase fracture risk. We hypothesized that a newer generation densitometer increases the number of evaluable vertebrae and vertebral fractures detec...
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Purpose Many osteoporotic vertebral fractures are not clinically recognized but increase fracture risk. We hypothesized that a newer generation densitometer increases the number of evaluable vertebrae and vertebral fractures detected. We also explored the impact of reader experience on vertebral fracture assessment (VFA) interpretation.
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In anaerobic leach-bed reactors (LBRs) co-digesting an easily-and a slowly-degradable substrate, the importance of the leachate flush both on extracting volatile fatty acids (VFAs) at the beginning of newly-started batches and on ...
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In anaerobic leach-bed reactors (LBRs) co-digesting an easily-and a slowly-degradable substrate, the importance of the leachate flush both on extracting volatile fatty acids (VFAs) at the beginning of newly-started batches and on their consumption in mature reactors was tested. Regarding VFA extraction three leachate flush-rate conditions were studied: 0.5, 1 and 2 L kg(-1) TS d(-1). Results showed that increasing the leachate flush-rate during the acidification phase is essential to increase degradation kinetics. After this initial phase, leachate injection is less important and the flush-rate could be reduced. The injection in mature reactors of leachate with an acetic acid concentration of 5 or 10 g L-1 showed that for an optimized VFA consumption in LBRs, VFAs should be provided straight after the methane production peak in order to profit from a higher methanogenic activity, and every 6-7 h to maintain a high biogas production rate. (C) 2017 Elsevier Ltd. All rights reserved.
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Osteoporosis is an important global health problem resulting in fragility fractures. The vertebrae are the commonest site of fracture resulting in extreme illness burden, and having the highest associated mortality. International ...
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Osteoporosis is an important global health problem resulting in fragility fractures. The vertebrae are the commonest site of fracture resulting in extreme illness burden, and having the highest associated mortality. International studies show that vertebral fractures (VF) increase in prevalence with age, similarly in men and women, but differ across different regions of the world. Ireland has one of the highest rates of hip fracture in the world but data on vertebral fractures are limited. In this study we examined the prevalence of VF and associated major risk factors, using a sample of subjects who underwent vertebral fracture assessment (VFA) performed on 2 dual-energy X-ray absorptiometry (DXA) machines. A total of 1296 subjects aged 40 years and older had a valid VFA report and DXA information available, including 254 men and 1042 women. Subjects had a mean age of 70 years, 805 (62%) had prior fractures, mean spine T-score was - 1.4 and mean total hip T-scores was - 1.2, while mean FRAX scores were 15.4% and 4.8% for major osteoporotic fracture and hip fracture, respectively. Although 95 (7%) had a known VF prior to scanning, 283 (22%) patients had at least 1 VF on their scan: 161 had 1, 61 had 2, and 61 had 3 or more. The prevalence of VF increased with age from 11.5% in those aged 40-49 years to > 33% among those aged >= 80 years. Both men and women with VF had significantly lower BMD at each measured site, and significantly higher FRAX scores, P < 0.01. These data suggest VF are common in high risk populations, particularly older men and women with low BMD, previous fractures, and at high risk of fracture. Urgent attention is needed to examine effective ways to identify those at risk and to reduce the burden of VF.
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This paper investigates the possibility of determining concentrations of acetate, propionate and butyrate in rumen fluid by Fourier transform mid-infrared (FTIR) transmission spectroscopy. A total of 308 samples were used for cali...
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This paper investigates the possibility of determining concentrations of acetate, propionate and butyrate in rumen fluid by Fourier transform mid-infrared (FTIR) transmission spectroscopy. A total of 308 samples were used for calibration of the FTIR instrument, normally used for milk analysis. The samples consisted of semi-artificial rumen fluids, spiked with acetate, propionate and butyrate with and without added bicarbonate and phosphate. The Test set consisted of 123 rumen in vitro samples with a mean value for the sum of the three volatile fatty acids of 5.5g/L (84mM), determined by high-performance liquid chromatography (HPLC). Stepwise regression was applied to find suitable wavelengths for predictions, mainly in the region of 6.3-10om. A total of 12-13 wavelengths were used for the prediction equations and resulted in mean prediction errors (MPE) ranging from 0.031 to 0.043g/L (approximately 0.5mM) for the three VFAs and ratios of population standard deviation (SD) to SD of the regressions>11.6. The calibration equation predicted the Test set well, with a MPE of 0.074, 0.066 and 0.119 for acetate, propionate and butyrate, respectively. More than 0.5 of the mean square prediction error was due to non-random errors which it should be possible to adjust for by use of calibration samples. A rough estimate also indicated that 0.09-0.16 of the mean square prediction error was due the HPLC method. The FTIR method is recommended for applications were required measurement accuracies are in the range of 1mM.
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