Hydrogen adsorption capacities of multi-walled boron nitride nanotubes and nanotube arrays: a grand canonical Monte Carlo study.

Hydrogen adsorption in multi-walled boron nitride nanotubes and their arrays was studied using grand canonical Monte Carlo simulation. The results show that hydrogen storage increases with tube diameter and the distance between the tubes in multi-walled boron nitride nanotube arrays. Also, triple-walled boron nitride nanotubes present the lowest level of hydrogen physisorption, double-walled boron nitride nanotubes adsorb hydrogen better when the diameter of the inner tube diameter is sufficiently large, and single-walled boron nitride nanotubes adsorb hydrogen well when the tube diameter is small enough. Boron nitride nanotube arrays adsorb hydrogen, but the percentage of adsorbed hydrogen (by weight) in boron nitride nanotube arrays is rather similar to that found in multi-walled boron nitride nanotubes. Also, when the Langmuir and Langmuir-Freundlich equations were fitted to the simulated data, it was found that multi-layer adsorptivity occurs more prominently as the number of walls and the tube diameter increase. However, in single-walled boron nitride nanotubes with a small diameter, the dominant mechanism is monolayer adsorptivity.

Distally based sural fasciocutaneous flap for soft tissue reconstruction of the distal leg, ankle and foot defects.

BACKGROUND: Soft tissue management around the lower third of the leg and foot presents a considerable challenge to the reconstructive plastic surgeon. The options in this region are limited. A durable flap is the preferred option for coverage of such defects. This descriptive study was conducted at Hayatabad Medical Complex and Said Anwar Medical Centre Peshawar over a period of 4 years to evaluate the efficacy of distally based Sural flap in coverage of the lower third of leg, ankle and foot defects, in 25 patients. METHODS: A descriptive study was conducted at the department of Plastic and Reconstructive Surgery at Hayatabad Medical Complex and Said Anwar Medical centre Peshawar. 25 patients with soft tissue defects over the distal leg and foot were included in this study. Distally based sural fasciocutaneous flap was used for coverage in all cases and its survival, successful coverage of the defect and donor site morbidity studied. RESULTS: Out of 25 flaps, 20 showed complete survival (80%). Partial flap loss was found in 2 patients (8%), marginal flap necrosis in 2 patients (8%) and complete loss in 1 patient (4%). CONCLUSIONS: The distally based sural flap is a versatile and reliable flap for the coverage of soft tissue defects of the distal lower extremity. The procedure is done as a single stage; the dissection is easy with short operating time and minimal morbidity.