Metallic fixation systems are currently the gold standard for fracture fixation but have problems including stress shielding, palpability and temperature sensitivity. Recently, resorbable systems have gained interest because they avoid removal and may improve bone remodelling due to the lack of stress shielding. However, their use is limited to paediatric craniofacial procedures mainly due to the laborious implantation requirements. Here we prepare and characterize a new family of resorbable screws prepared from silk fibroin for craniofacial fracture repair. In vivo assessment in rat femurs shows the screws to be self-tapping, remain fixed in the bone for 4 and 8 weeks, exhibit biocompatibility and promote bone remodelling. The silk-based devices compare favourably with current poly-lactic-co-glycolic acid fixation systems, however, silk-based devices offer numerous advantages including ease of implantation, conformal fit to the repair site, sterilization by autoclaving and minimal inflammatory response.

SUMMARYWhen generating gaits for soft robots (those with no explicit joints), it is not evident that undulating control schemes are the most efficient. In considering alternative control schemes, however, the computational costs of evaluating continuum mechanic models of soft robots represent a significant bottleneck. We consider the use of lumped dynamic models for soft robotic systems. Such models have not been employed previously to design gaits for soft robotic systems, though they are widely used to simulate robots with compliant joints. A major question is whether these methods are accurate enough to be representations of soft robots to enable gait design and optimization. This paper addresses the potential “reality gap” between simulation and experiment for the particular case of a soft caterpillar-like robot. Experiments with a prototype soft crawler demonstrate that the lumped dynamic model can capture essential soft-robot mechanics well enough to enable gait optimization. Significantly, experiments verified that a prototype robot achieved high performance for control patterns optimized in simulation and dramatically reduced performance for gait parameters perturbed from their optimized values.

HistoryAn approximately 2.5-year-old sexually intact female bearded dragon (Pogona vitticeps) was evaluated for acute onset of listlessness, weakness, and pallor of the entire integument. On initial examination, the bearded dragon was lethargic, pale, and subjectively dehydrated. A serum biochemical analysis revealed a glucose concentration of 502 mg/dL (reference range, 149 to 253 mg/dL) and a uric acid concentration of 10.3 mg/dL (reference range, 1.8 to 7.0 mg/dL). A CBC revealed an Hct of 18% (reference range, 24% to 36%). The bearded dragon was hospitalized overnight and given enteral fluid therapy by gavage tube; the bearded dragon was also soaked in tepid water for 10 minutes. The following day, the bearded dragon was more alert and less pale and was discharged with instructions to soak daily and repeat the serum biochemical analysis in 1 week.Four days later, the bearded dragon was admitted for a marked decrease in appetite and continued lethargy and pallor since discharge. Physical examination findings were unchanged from those found at the time of initial admission. A follow-up serum biochemical analysis revealed resolution of hyperglycemia (glucose, 196 mg/dL) and hyperuricemia (uric acid, 1.8 mg/dL). Survey radiographs of the whole body were obtained (Figure 1).Determine whether additional imaging studies are required, or make your diagnosis from Figure 1-then turn the page →

No abstract

No abstract