Antenatal imaging diagnosis of thoraco-omphalopagus conjoined twins.

Conjoined twins occur in an estimated one in every 200,000 live births. The etiology remains largely speculative, with genetic and environmental factors being considered. The thoraco-omphalopagus type accounts for approximately 40% of cases, making it a focal point for clinical and radiological research.

Vibrational and thermal properties of ScN and YN: quasi-harmonic approximation calculations and anharmonic effects.

The structural, vibrational and thermal properties of rocksalt ScN and YN are investigated by using a first-principles plane-wave approach. The results are discussed in comparison with the similarly calculated results for rocksalt MgO and zincblende AlN. The thermal expansivity (α(V)) computed within the quasi-harmonic approximation shows that there are significant anharmonic effects in ScN and YN, which are comparable to those in MgO.