Although coherent twin boundaries require little energy to form in nanoscale single crystals, their influence on properties can be dramatic. In recent years, some important steps forward have been made in understanding and controlling twinning processes at the nanoscale, making possible the fabrication of nanoengineered twinning superlattices in crystalline nanowires. These advances have opened...

In this study, the concept of "twinning induced plasticity (TWIP) alloys" is broadened, and the underlying intrinsic microscopic mechanisms of the general TWIP effect are intensively explored. For the first aspect, "TWIP copper alloys" was proposed following the concept of "TWIP steels", as they share essentially the same strengthening and toughening mechanisms. For the second aspect, three int...

We employ classical molecular dynamics to calculate elastic properties and to model the nucleation and propagation of deformation twins in calcite, both as a pure crystal and with magnesium and aspartate inclusions. The twinning is induced by applying uniaxial strain to the crystal and relaxing all stress components except the uniaxial component. A detailed analysis of the atomistic processes r...

BACKGROUND The tendency to conceive dizygotic (DZ) twins is a complex trait influenced by genetic and environmental factors. To search for new candidate loci for twinning, we conducted a genome-wide linkage scan in 525 families using microsatellite and single nucleotide polymorphism marker panels. METHODS AND RESULTS Non-parametric linkage analyses, including 523 families containing a total o...

The true incidence of monoamniotic twinning has been almost impossible to determine accurately because it requires closer inspection of the membranes and placenta at delivery than is usually performed. Sonography of 3440 patients presenting for genetic amniocentesis identified 39 twin gestations, one of which was monoamniotic (0.026%). Prospectively with ultrasound, four of the twin gestations ...

MRI Department, onjoined twins, rare variants of monozygotic twins, result from an incomplete division of Nanavati Hospital, C the embryonic disk. Conjoined twinning occurs once in every 50,000–100,000 births. Mumbai, India Cephalothoracopagus, a very rare variant of conjoined twins occurs once in every three-million births. Early prenatal diagnosis is desirable, given the poor prognosis. Corre...

OBJECTIVES To provide information on twin deliveries among Igbos in a rural/semi-urban community of South-Eastern Nigeria, and compare the twinning rate with data from the other two major tribes. METHODS An analysis of the records of deliveries conducted over a 20-year period in a rural/semi-urban community of South-Eastern Nigeria. RESULTS The twinning rate of the community was 1:24, and i...

A 7-year-old girl was admitted to the hospital for anaemia, secondary to intestinal blood los (melaena). She was found to have 45,X Turner's syndrome. Her identical twin sister also had Turner's syndrome with a 45,X chromosome complement. According to various criteria the probability of monozygosity was 0.9905. Although the incidence of twinning is greater than usual in families of patients wit...