Collagen fibril alignment and deformation during tensile strain of leather: a small-angle X-ray scattering study     

Basil-Jones MM  Edmonds RL  Norris GE  Haverkamp RG 《Journal of agricultural and food chemistry》2012,60(5):1201-1208

The distribution and effect of applied strain on the collagen fibrils that make up leather may have an important bearing on the ultimate strength and other physical properties of the material. While sections of ovine and bovine leather were being subjected to tensile strain up to rupture, synchrotron-based small-angle X-ray scattering (SAXS) spectra were recorded edge-on to the leather at points from the corium to the grain. Measurements of both fibril orientation and collagen d spacing showed that, initially, the fibers reorient under strain, becoming more aligned. As the strain increases (5-10% strain), further fibril reorientation diminishes until, at 37% strain, the d spacing increases by up to 0.56%, indicating that significant tensile forces are being transmitted to individual fibrils. These changes, however, are not uniform through the cross-section of leather and differ between leathers of different strengths. The stresses are taken up more evenly through the leather cross-section in stronger leathers in comparison to weaker leathers, where stresses tended to be concentrated during strain. These observations contribute to our understanding of the internal strains and structural changes that take place in leather under stress.  相似文献   

The effect of high correlated colour temperature office lighting on employee wellbeing and work performance     

Peter R Mills  Susannah C Tomkins  Luc JM Schlangen 《Journal of circadian rhythms》2007,5(1):2-9

Background  

The effects of lighting on the human circadian system are well-established. The recent discovery of 'non-visual' retinal receptors has confirmed an anatomical basis for the non-image forming, biological effects of light and has stimulated interest in the use of light to enhance wellbeing in the corporate setting.  相似文献   

Deleterious Effects of Progestagen Treatment in VEGF Expression in Corpora Lutea of Pregnant Ewes     

CA Letelier  MA Sanchez  RA Garcia‐Fernandez  B Sanchez  P Garcia‐Palencia  A Gonzalez‐Bulnes  JM Flores 《Reproduction in domestic animals》2011,46(3):481-488

The aim of the current study was to determine the possible effects of progestagen oestrous synchronization on vascular endothelial growth factor (VEGF) expression during sheep luteogenesis and the peri‐implantation period and the relationship with luteal function. At days 9, 11, 13, 15, 17 and 21 of pregnancy, the ovaries from 30 progestagen treated and 30 ewes cycling after cloprostenol injection were evaluated by ultrasonography and, thereafter, collected and processed for immunohistochemical evaluation of VEGF; blood samples were drawn for evaluating plasma progesterone. The progestagen‐treated group showed smaller corpora lutea than cloprostenol‐treated and lower progesterone secretion. The expression of VEGF in the luteal cells increased with time in the cloprostenol group, but not in the progestagen‐treated group, which even showed a decrease between days 11 and 13. In progestagen‐treated sheep, VEGF expression in granulosa‐derived parenchymal lobule capillaries was correlated with the size of the luteal tissue, larger corpora lutea had higher expression, and tended to have a higher progesterone secretion. In conclusion, the current study indicates the existence of deleterious effects from exogenous progestagen treatments on progesterone secretion from induced corpora lutea, which correlate with alterations in the expression of VEGF in the luteal tissue and, this, presumably in the processes of neoangiogenesis and luteogenesis.  相似文献   

Single Layer Centrifugation of Stallion Spermatozoa through Androcoll™‐E does not Adversely Affect their Capacitation‐Like Status,as Measured by CTC Staining     

A‐S Bergqvist  A Johannisson  L Bäckgren  A‐M Dalin  H Rodriguez‐Martinez  JM Morrell 《Reproduction in domestic animals》2011,46(1):e74-e78

This study was designed to evaluate the effect of single layer centrifugation (SLC) and subsequent cold storage on stallion sperm capacitation‐like status and acrosome reaction. Three stallions were included in the study, with three ejaculates per stallion. The samples were examined 4, 24 and 72 h after collection, extension and SLC, with storage at 6°C. Sperm capacitation‐like status was investigated using the fluorescent dye chlortetracycline (CTC). There was no difference in capacitation‐like status between colloid‐selected and non‐selected spermatozoa. Sperm motility decreased significantly during cold storage, whereas the proportion of apparently capacitated spermatozoa increased. There was no change in the proportion of acrosome‐reacted spermatozoa. In conclusion, SLC through Androcoll?‐E does not adversely affect the capacitation‐like status of stallion spermatozoa, although it did increase with time during cold storage.  相似文献   

Effects of preparation method, shear force, and exposure to collagen on release of growth factors from equine platelet-rich plasma     

Textor JA  Norris JW  Tablin F 《American journal of veterinary research》2011,72(2):271-278

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Effects of strain and different skip-a-day feed restriction periods on the growth performance of broiler chickens     

Benyi K  Acheampong-Boateng O  Norris D 《Tropical animal health and production》2011,43(4):871-876

The effects of 6, 10 and 14 days of skip-a-day feed removal during the starter and grower periods on the growth performance of Ross 308 and Hubbard broiler chickens were studied in a 49-day production period. Ross 308 was superior to Hubbard in weight gain, market weight and feed utilization but consumed more feed, deposited more abdominal fat and had a higher mortality rate. Overall, feed removal improved feed efficiency, had insignificant effects on abdominal fatness and mortality rate and reduced feed intake, weight gain and market weight. On each restricted-feeding regime, the birds gained as much weight as their fully fed counterparts during the period of resumed full feeding but were unable to compensate fully for the weight loss and were lighter at the end of the trial. It is suggested that for profitable broiler production under tropical conditions, Ross 308 and skip-a-day feed removal for less than 6 days from 7 to 17 days of age be considered.  相似文献   

Predictors of adolescent weight status and central obesity in rural South Africa     

Kimani-Murage EW  Kahn K  Pettifor JM  Tollman SM  Klipstein-Grobusch K  Norris SA 《Public health nutrition》2011,14(6):1114-1122

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Chlamydia psittaci: a suspected cause of reproductive loss in three Victorian horses     

R Akter  AW Stent  FM Sansom  JR Gilkerson  C Burden  JM Devlin  AR Legione  CM El-Hage 《Australian veterinary journal》2020,98(11):570-573

Chlamydia psittaci was detected by PCR in the lung and equine foetal membranes of two aborted equine foetuses and one weak foal from two different studs in Victoria, Australia. The abortions occurred in September 2019 in two mares sharing a paddock northeast of Melbourne. The weak foal was born in October 2019 in a similar geographical region and died soon after birth despite receiving veterinary care. The detection of C. psittaci DNA in the lung and equine foetal membranes of the aborted or weak foals and the absence of any other factors that are commonly associated with abortion or neonatal death suggest that this pathogen may be the cause of the reproductive loss. The detection of C. psittaci in these cases is consistent with the recent detection of C. psittaci in association with equine abortion in New South Wales. These cases in Victoria show that C. psittaci, and the zoonotic risk it poses, should be considered in association with equine reproductive loss in other areas of Australia.  相似文献   

Suspected immune-mediated polysynovitis and serositis in a horse     

JM LUMSDEN 《Australian veterinary journal》1990,67(12):470-471

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Absence of evidence is not evidence of absence     

DG ALTMAN  JM BLAND 《Australian veterinary journal》1996,74(4):311-311

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