108 research outputs found

    Development, implementation, and validation of a generic nutrient recovery model (NRM) library

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    The reported research developed a generic nutrient recovery model (NRM) library based on detailed chemical solution speciation and reaction kinetics, with focus on fertilizer quality and quantity as model outputs. Dynamic physicochemical three-phase process models for precipitation/crystallization, stripping and acidic air scrubbing as key unit processes were developed. In addition, a compatible biological-physicochemical anaerobic digester model was built. The latter includes sulfurgenesis, biological N/P/K/S release/uptake, interactions with organics, among other relevant processes, such as precipitation, ion pairing and liquid-gas transfer. Using a systematic database reduction procedure, a 3- to 5-fold improvement of model simulation speeds was obtained as compared to using full standard thermodynamic databases. Missing components and reactions in existing standard databases were discovered. Hence, a generic nutrient recovery database was created for future applications. The models were verified and validated against a range of experimental results. Their functionality in terms of increased process understanding and optimization was demonstrated

    Effect of hot boning on colour stability and antioxidant enzyme activities in beef inner and outer biceps femoris

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    Meat from double-muscled Belgian Blue cattle is characterized by a fast pH decline and slow temperature fall post mortem (pm), which may provoke heat shortening (pH35°C) and negatively affect meat quality, particularly in deeper muscles of the hindquarter. The aim of this study was to investigate the effect of hot boning (within 2 hours pm) on colour and colour stability and on antioxidant enzyme activities (superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GSH-Px)) in inner and outer Biceps femoris (IBF and OBF) from 7 Belgian Blue young bulls (mean age and carcass weight 22.7 months and 496 kg respectively). The mean duration of heat shortening was 3.4 hours for the cold-boned IBF, whereas there was no period of heat shortening in the hot-boned IBF and in the cold- and hot-boned OBF. The colour L*-value was higher in the cold-boned IBF than OBF (49.3 and 37.6 respectively; P<0.05) resulting in two-toning, whereas there was no significant difference between hot-boned IBF and OBF (33.8 and 34.3 respectively). Concomitantly, the decrease in a*-value and increase in %metmyoglobin over a 7 day display period was higher (P<0.05) for the cold-boned IBF compared to the hot-boned IBF and the cold- and hot-boned OBF. The activities of CAT, GSH-Px and SOD for the IBF and OBF were not significantly different between hot- and cold-boned samples. Hot boning of Biceps femoris in beef carcasses has distinct advantages over cold boning, especially for avoiding heat shortening in the inner part of the muscle and for increasing the colour uniformity in the muscle

    Biomechanical and biochemical properties of the thoracic aorta in warmblood horses, Friesian horses, and Friesians with aortic rupture

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    Background: Thoracic aortic rupture and aortopulmonary fistulation are rare conditions in horses. It mainly affects Friesian horses. Intrinsic differences in biomechanical properties of the aortic wall might predispose this breed. The biomechanical and biochemical properties of the thoracic aorta were characterized in warmblood horses, unaffected Friesian horses and Friesians with aortic rupture in an attempt to unravel the underlying pathogenesis of aortic rupture in Friesian horses. Samples of the thoracic aorta at the ligamentum arteriosum (LA), mid thoracic aorta (T1) and distal thoracic aorta (T2) were obtained from Friesian horses with aortic rupture (A), nonaffected Friesian (NA) and warmblood horses (WB). The biomechanical properties of these samples were determined using uniaxial tensile and rupture assays. The percentages of collagen and elastin (mg/mg dry weight) were quantified. Results: Data revealed no significant biomechanical nor biochemical differences among the different groups of horses. The distal thoracic aorta displayed an increased stiffness associated with a higher collagen percentage in this area and a higher load-bearing capacity compared to the more proximal segments. Conclusions: Our findings match reported findings in other animal species. Study results did not provide evidence that the predisposition of the Friesian horse breed for aortic rupture can be attributed to altered biomechanical properties of the aortic wall

    Genitoplasty in newborn females with adrenogenital syndrome : focus on the reconstruction technique and its outcomes

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    The adrenogenital syndrome is an autosomal recessive disorder in which an enzyme defect in the steroid pathway leads to excessive prenatal exposure of androgens. In the female fetus, masculinization of the external genitalia is observed. Surgery aims for functional and aesthetical reconstruction. Many techniques have been described. A video of our modified pull-through reconstruction technique is hereby presented. A retrospective descriptive database was created with patients who underwent genitoplasty for a CAH-associated genital condition. A video demonstrating the reconstructive technique was recorded while operating on a 9-month-old girl. Prior to surgery a cystoscopy is performed to evaluate the length of the urogenital sinus. Surgery starts with creating a reversed U-flap, after which the urogenital sinus is mobilized. The corpora cavernosa are released and the neurovascular bundle is isolated. To create vaginal space the urogenital sinus is subsequently separated. The vaginal introitus is anchored to the perineal skin flap. Labia minora are created by splitting the preputial skin. Finally excessive skin tissue is resected. Twenty-two female patients underwent reconstructive surgery for the adrenogenital syndrome in a tertiary referral centre over 16 years. Median age at surgery was 3 months (0-190). Median follow-up was 36 months (0-108) after surgery. A good functional and aesthetical outcome was observed. The modified pull-through technique, illustrated by this video, provided satisfactory results with a low complication rate. Follow-up until adulthood is needed to evaluate long-term outcomes

    Development, implementation, and validation of a generic nutrient recovery model (NRM) library

    Get PDF
    The reported research developed a generic nutrient recovery model (NRM) library based on detailed chemical solution speciation and reaction kinetics, with focus on fertilizer quality and quantity as model outputs. Dynamic physicochemical three-phase process models for precipitation/crystallization, stripping and acidic air scrubbing as key unit processes were developed. In addition, a compatible biological-physicochemical anaerobic digester model was built. The latter includes sulfurgenesis, biological N/P/K/S release/uptake, interactions with organics, among other relevant processes, such as precipitation, ion pairing and liquid-gas transfer. Using a systematic database reduction procedure, a 3- to 5-fold improvement of model simulation speeds was obtained as compared to using full standard thermodynamic databases. Missing components and reactions in existing standard databases were discovered. Hence, a generic nutrient recovery database was created for future applications. The models were verified and validated against a range of experimental results. Their functionality in terms of increased process understanding and optimization was demonstrated
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