Tendon allografts are commonly used to replace damaged anterior cruciate ligaments (ACL). Some of the sterilization and preservation techniques used by tissue banks with tendon allografts are thought to impair the mechanical properties of graft tissues. The tensile mechanical properties of porcine toe extensor tendons were measured using a dynamic testing machine following either freezing, freeze-drying, freezing then irradiation at 25 kGy (2.5 MRad), freeze-drying then irradiation, or freeze-drying then ethylene oxide gas sterilization. There was a small but significant difference in Young’s modulus between the frozen group (0.88 GPa ± 0.09 SD) and both the fresh group (0.98 GPa ± 0.12 SD) and the frozen irradiated group (0.97 GPa ± 0.08 SD). No values of Young’s modulus were obtained for the freeze-dried irradiated tendons. The ultimate tensile stress (UTS) of the freeze-dried irradiated group (4.7 MPa ± 4.8 SD) was significantly different from both the fresh and the frozen irradiated groups, being reduced by approximately 90 percent. There were no significant changes in UTS or Young’s modulus between any of the other groups. If irradiation is to be used to sterilize a tendon replacement for an ACL it must take place after freeze-drying to maintain mechanical properties.
Although environmental enrichment is known to improve laboratory rodent wellbeing and enhance scientific data collection, relatively little is known with regards to the type of enrichment that might be useful for zebrafish (Danio rerio). Therefore, this study explored if zebrafish displayed preferences for a range of enrichments, including substrates, artificial plants, combinations thereof and airstones. Tanks divided into two compartments containing different enrichment cues were used to determine the preferences of zebrafish housed in pairs and groups of eight. When comparing time spent in enriched versus barren compartments, dominant individuals in a pair displayed a preference for substrate and behaviourally excluded the subordinate (p < 0.05). In groups there was a preference for all substrate (p < 0.01) and plant (p < 0.05) enrichments over barren conditions. The strongest preference was for gravel substrate and images of gravel attached to the bottom of the tank. When preferences were compared for different enrichments, gravel (both sexes, p < 0.01) again emerged as the cue attracting the most significant preferences, with any combination featuring gravel substrate preferred over any combination featuring sand (p < 0.05). The study has demonstrated that zebrafish reared in barren conditions preferred structural enrichment over standard conditions; however, when fish were held in pairs this was influenced by dominance status and in groups this was influenced by gender.
1 September 1996 in Pflügers Archiv - European Journal of Physiology
Paper-based microfluidic channels were created from solid wax printing, and the resultant 2D wax-printed paper substrates were used for paper spray (PS) mass spectrometry (MS) analysis of small organic compounds. Controlling fluid flow at the tip of the wax-printed paper triangles enabled the use of lower spray voltages (0.5–1 kV) and extended signal lifetime (10 minutes) in PS-MS. High sensitivity (sub ng mL−1 levels) and quantitation precision (<10% RSD) have been achieved in the analysis of illicit drugs in 4 μL of raw urine (fresh and dry), as well as corrosion inhibitors and pesticides in water samples. The reported study encourages the future development of disposable 3D microfluidic paper-based analytical devices, which function with simple operation but capable of on-chip analyte detection by MS; such a device can replace the traditional complex laboratory procedures for MS analysis to enable on-site in situ sampling with portable mass spectrometers.
One third of food produced globally is wasted. Disposal of this waste is costly and is an example of poor resource management in the face of elevated environmental concerns and increasing food demand. Providing this waste as feedstock for black soldier fly (Hermetia illucens) larvae (BSFL) has the potential for bio-conversion and valorisation by production of useful feed materials and fertilisers. We raised BSFL under optimal conditions (28 °C and 70% relative humidity) on seven UK pre-consumer food waste-stream materials: fish trimmings, sugar-beet pulp, bakery waste, fruit and vegetable waste, cheese waste, fish feed waste and brewer’s grains and yeast. The nutritional quality of the resulting BSFL meals and frass fertiliser were then analysed. In all cases, the volume of waste was reduced (37–79%) and meals containing high quality protein and lipid sources (44.1 ± 4.57% and 35.4 ± 4.12%, respectively) and frass with an NPK of 4.9-2.6-1.7 were produced. This shows the potential value of BSFL as a bio-convertor for the effective management of food waste.
7 October 2001 in Proceedings Of The Royal Society B-Biological Sciences
Animals perform a vast array of motor activities. Although it has generally been accepted that muscles are well suited to the function that they must perform, specialization for performing one function may compromise their ability for carrying out another. We examined this principle in the toadfish muscular system: slow–twitch red and fast–twitch white myotomal muscles are used for powering swimming at relatively low frequencies, while the superfast swimbladder muscle powers mating calls by contracting at 100 Hz. We measured muscle power output over a wide range of frequencies. The red and white locomotory muscles could not generate power over ca. 2.2 and 12 Hz, respectively and, hence, could not power sound production. In contrast, the swimbladder muscle has many specializations that permit it to generate power at frequencies in excess of 100 Hz. However, these specializations drastically reduce its power output at low frequencies: the swimbladder muscle generated only one–twentieth of the power of the red muscle and one–seventh of the power of the white muscle at the frequencies used during swimming. To generate the same total power needed for swimming would require unfeasibly large amounts of swimbladder muscle that could not fit into the fish. Hence, the designs of the swimbladder and locomotory muscles are mutually exclusive.