background: approximately 205 million pregnancies occur each year in the worldwide. on the other hand, spontaneous abortion has been reported in 15-20% of all diagnosed pregnancies. the most common cause of spontaneous abortion is chromosomal abnormalities of the embryo. robertsonian translocation carriers specially 21-14 are the most common balanced rearrangement among the carrier couples with...

A concise synthesis of homocitric acid lactone was developed to accommodate systematic placement of carbon isotopes (specifically (13)C) for detailed studies of this cofactor. This new route uses a chiral allylic alcohol, available in multigram quantities from enzymatic resolution, as a starting material, which transposes asymmetry through an Ireland-Claisen rearrangement.

a theoretical study of the kinetic and mechanism of 3-aug-cope rearrangement in gas phase was performed usingdet methods at b3lyp levels of theory with 6-3114ig(d,p) bass set at 298.i5k. equilibrium moleculargeometries and harmonic vibrational frequencies of the reactant, transition state did product were calculated. then,rate constant and activation thermodynamics parameters were calculated an...

microstructural investigation of low molecular weight 1,4-polybutadiene (1,4-pbd) was studied by 1h and 13c nuclear magnetic resonance spectroscopy (nmr). the isomer contents of 1,4-cis, 1,4-trans and 1,2- vinyl in polybutadiene microstructure were determined. the number average molecular weight for low molecular weight polybutadiene was measured by nmr techniques and comparison was made with g...

Although abnormalities involving the short arm of chromosome 12 (12p) are one of the most frequently observed rearrangements in childhood acute lymphoblastic leukemia (ALL), little is known about the frequency of different structural abnormalities and their relationship to the status of the ETV6 (also named TEL) gene in this region. Of 815 children with newly diagnosed ALL, 94 (11.5%) had a tot...

OBJECTIVE To determine the frequency of rearrangement of the myeloid-lymphoid leukaemia gene in acute leukaemia in Hong Kong Chinese children. DESIGN Immunophenotyping, cytogenetic, and molecular analysis. SETTING Regional hospital, Hong Kong. PARTICIPANTS Bone marrow or peripheral blood samples were taken from 27 children aged 16 years or younger with acute leukaemia, from September 1995...

Wiener amalgam spaces are a class of spaces of functions or distributions defined by a norm which amalgamates a local criterion for membership in the space with a global criterion. Versions of such amalgam spaces have arisen independently many times in the literature, and often provide a natural and compelling context for formulating results. As one illustration of the shortcomings of the usual...

Cross-striated muscles of frogs and rats were fixed in 3.3 per cent lead nitrate solution. Frozen sections 30 micra thick were mounted in different media and observed by polarization microscopy. The subneural apparatus of myoneural junctions exhibits a strong birefringence in these sections. Birefringence is exerted by a highly organized lipoprotein framework (postsynaptic material) which build...

With the advent of large-scale DNA physical mapping and se-quencing, studies of genome rearrangements are becoming increasingly important in evolutionary molecular biology. From a computational perspective, study of evolution based on rearrangements leads to rearrangement distance problem, i.e., computing the minimum number of rearrangement events required to transform one genome into another. ...