3-Cyano-11-oxo-3,4-seco-12a-aza-C-homoolean-4(23)-en-28-oic acid methyl ester

The title compound, C31H48N2O3, is a Beckmann rearrangement product. The isopropenyl and meth­oxy­carbonyl groups have β-orientations, whereas the 2-cyano­ethyl group has an α-orientation. In the triterpenoid skeleton, the seven-membered lactam ring, as well as the three six-membered carbocyclic rings, have chair conformations. In the crystal, mol­ecules are linked via nonclassical C—H⋯O hydrogen bonds into layers parallel to the ab plane

South Dakota Sex and Age Structure, 1980-1990

Age and sex structure of a population plays a critical role in determining the needs and lifestyle of that population. One community, for example, may have a high number of children and youth, a sure indicator of need for teachers and schools; another community may have a high proportion of elderly, indicating a greater need for medical services. People of different ages or gender also may have different consumer preferences. When business leaders and community leaders know the age and sex structure of their community, they can use that information to help direct resources toward meeting particular needs in education, housing, recreation, and medical and social services. Although no two communities are likely to have identical age and sex structures, there are general patterns that are helpful for identifying potential population needs. Population pyramids and indices are useful for illustrating these patterns

Labeling Adipose-Derived Stem Cells with Hoechst 33342: Usability and Effects on Differentiation Potential and DNA Damage

Adipose-derived stem cells (ASCs) have been extensively studied in the field of stem cell research and possess numerous clinical applications. Cell labeling is an essential component of various experimental protocols and Hoechst 33342 (H33342) represents a cost-effective and easy methodology for live staining. The purpose of this study was to evaluate the labeling of rat ASCs with two different concentrations of H33342 (0.5 μg/mL and 5 μg/mL), with particular regard to usability, interference with cell properties, and potential DNA damage. Hoechst 33342 used at a low concentration of 0.5 μg/mL did not significantly affect cell proliferation, viability, or differentiation potential of the ASCs, nor did it cause any significant DNA damage as measured by the olive tail moment. High concentrations of 5 μg/mL H33342, however, impaired the proliferation and viability of the ASCs, and considerable DNA damage was observed. Undesirable colabeling of unlabeled cocultivated cells was seen in particular with higher concentrations of H33342, independent of varying washing procedures. Hence, H33342 labeling with lower concentrations represents a usable method, which does not affect the tested cell properties. However, the colabeling of adjacent cells is a drawback of the technique

Resonant Phenomena in Antihydrogen-Hydrogen Scattering

We present a treatment of cold hydrogen-antihydrogen collisions based on the asymptotic properties of atom-antiatom interactions. We derive general formulas for the elastic and inelastic cross sections and for the scattering lengths and analyze their sensitivity to the parameters characterizing the inelasticity of the collision process. Given the inelasticity, we obtain bounds for the complex scattering length. We investigate the influence of strong nuclear forces and the isotope effects in $\bar{\rm H}{\rm H}$ and $\bar{\rm H}{\rm D}$ collisions and demonstrate enhancement of these effects due to the presence of the near-threshold narrow ${\rm H}\bar{\rm H}$ ($\bar{\rm H}{\rm D}$) states. The values of the elastic and inelastic cross-sections with simultaneous account of rearrangement and strong forces are presented. General expressions for the (complex) energies of the near-threshold $\rm{H}\bar{\rm H}$ states are obtained.Comment: 26 pages 7 figure

Variational calculations for the hydrogen-antihydrogen system with a mass-scaled Born-Oppenheimer potential

The problem of proton-antiproton motion in the ${\rm H}$--${\rm \bar{H}}$ system is investigated by means of the variational method. We introduce a modified nuclear interaction through mass-scaling of the Born-Oppenheimer potential. This improved treatment of the interaction includes the nondivergent part of the otherwise divergent adiabatic correction and shows the correct threshold behavior. Using this potential we calculate the vibrational energy levels with angular momentum 0 and 1 and the corresponding nuclear wave functions, as well as the S-wave scattering length. We obtain a full set of all bound states together with a large number of discretized continuum states that might be utilized in variational four-body calculations. The results of our calculations gives an indication of resonance states in the hydrogen-antihydrogen system

Skeletal Structural Basis of Density Banding in the Reef Coral Montastrea Annularis

Density banding in coral skeletons can provide for reconstruction of the coral\u27s growth en- vironment over long periods. The physical differ- ences between low and high density portions of a skeletal band are not well understood. The skeletal architecture of M. annularis from Southeast Flor- ida, the Florida Keys, St. Croix, the Bahamas, and Mexico was compared in X-ray revealed high den- sity (HD), low density (LD), and stress HD bands. Density changes arose from differences in the size, but not spacing, of exothecal structural elements (horizontal dissepiments and vertical costae). En- dothecal architecture size (e.g., columella, dissepi- ments, septa) was relatively constant between den- sity band types. Results have implications for studies of coral growth, sclerochronology, and iso- topic/trace element composition

3β-Acet­oxy-12α-chloro-d-friedooleanan-28,14β-olide

The title compound, C32H49ClO4, was obtained along with nitrile and lactam products in the POCl3-catalysed Beckmann rearrangement from 3β-acet­oxy-12-hydroxyiminoolean-28-olic acid methyl ester. The mechanism of the transformation leading to the title compound remains unclear and requires further investigation. Rings A, B and E are in chair conformations, ring C has a twisted-boat conformation, ring D a conformation halfway between boat and twisted-boat and rings D and E are cis-fused. In the crystal, mol­ecules are connected by weak inter­molecular C—H⋯O hydrogen bonds into layers extending parallel to the bc plane

(E)-17β,19-Epoxy­methano-17,23,24-tridemethyl-4-nor-5β,18α-olean-3-one oxime

In the penta­cyclic triterpenoide skeleton of the title mol­ecule, C27H43NO2 [systematic name: (3E,3aS,5aR,5bR,7aR,11R,11aR,11bR,13aR,13bR)-5a,5b,10,10,13b-penta­methyl­icosa­hydro-1H-11,7a-(epoxy­methano)cyclo­penta­[a]chrysen-3-one oxime], the five-membered ring A has an envelope conformation, while the six-membered rings B–E adopt chair conformations. Rings A and B are cis-fused. The hydroximino group has an E configuration. Strong inter­molecular O—H⋯O hydrogen bonds link the mol­ecules into helical chains