Our data suggest positive correlation between amount of maxillary advancement and horizontal relapse as well as a positive correlation between history of cleft and horizontal relapse. Bone grafting of the maxillary osteotomy sites has a protective effect on the relapse.

Facial plastic and reconstructive surgeons are continually faced with the dilemma of what material to use for implantation and grafting. Tissue-engineered cartilage is a relatively new and exciting concept which utilizes chondrocytes and cultures them on a three-dimensional biodegradable template. This template/cell complex is first briefly incubated in vitro, then implanted into a recipient host. In situ the template resorbs and is replaced with new cartilage that is viable, compatible, and mature. This paper discusses the biochemical composition of cartilage, the concept of tissue engineering, advances in template quality, and cartilage immunogenicity. Future clinical applications of this type of graft research include microtia repair, facial reconstruction, rhinoplasty, and other facial cosmetic procedures.

No abstract

Water-quality observations in estuaries can be highly variable in time and space, making it difficult to quantify nutrient fluxes and to discriminate patterns. We measured nitrate, phosphate and ammonium concentrations in two shallow tidally dominated estuaries in Tauranga Harbour, New Zealand, during four periods (winter, start of spring, end of spring and summer) within 1 year, to determine the source of variability observed in a 19-year monitoring program. These measurements consisted of high-frequency monitoring during one 24-h period (covering a daytime flood-ebb tide and a night-time flood-ebb tide) at each estuary. Concentrations of nitrate and ammonium had distinctive tidal patterns, with rising values during ebb flows. This tidal asymmetry caused a net seaward flux of dissolved inorganic nitrogen (nitrate and ammonium), with higher exports at night. Net fluxes were 34–358 kg N per tidal cycle for nitrate and 22–93 kg N per tidal cycle for ammonium. Fluxes were large relative to previously published model-based predictions for the region, particularly during winter. Our results showed that estuarine sampling strategies need to account for tidal variability and the role of episodic runoff events, and highlighted the importance of correctly validated mass fluxes from field measurements for comparisons with nutrient-loading models.

The compressional wave velocity of rock in situ measured at four sites in the White Mountains of New Hampshire varies as a function of azimuth and is anisotropic. The anisotropy [(Vmax − Vmin)/Vmax], which ranged from 18% to 42%, is attributed to two sets of cracks with different azimuths and with total crack density of order of 0.2 at each site. The anisotropy in velocity correlates only approximately with the orientation of mapped joints at each site.