Structure of Equilenin at 100 K: an estrone-related steroid

The structure of the estrone-related steroid, Equilenin, C18H18O2 (systematic name 3-hy-droxy-13-methyl-11,12,13,14,15,16-hexa-hydro-cyclo-penta-[a]phen-anthren-17-one), has been determined at 100 K. The crystals are ortho-rhom-bic, P212121, and the absolute structure of the mol-ecule in the crystal has been determined by resonant scattering [Flack parameter = -0.05 (4)]. The C atoms of the A and B rings are almost coplanar, with an r.m.s. deviation from planarity of 0.0104 Å. The C ring has a sofa conformation, while the D ring has an envelope conformation with the methine C atom as the flap. The keto O atom and the methyl group are translated 0.78 and 0.79 Å, respectively, from the equivalent positions on 17β-estrone. In the crystal, mol-ecules are linked by O-H⋯O hydrogen bonds, forming chains parallel to the c-axis direction

What do we mean by the ‘underclass’?

Recent evidence points to the failure of the ‘troubled families’ programme launched by the Coalition government in 2011, a programme designed to intervene in the lives of the estimated 120,000 most behaviourally anti-social families in England and Wales. As John Macnicol argues, the concept of the ‘underclass’ underpinning this initiative has a long history, and has resurfaced in various forms for over a century in British politics and policy-makin

Engineering robust polar chiral clathrate crystals

This is the author's accepted manuscript. The final published article is available from the link below. Copyright @ Royal Society of Chemistry 2013.The R-(+)-enantiomeric form of Dianin's compound and the S-(+)-enantiomeric form of its direct thiachroman analogue both obtained chromatographically employing a cellulose tris(3,5-dimethylphenylcarbamate) column, are shown to undergo supramolecular assembly to form a polar clathrate lattice which is stable even in the absence of a consolidating guest component

Kinetic Studies by Nuclear Magnetic Resonance

Abstract Not Provided

A Study of Satellite Navigation, Dilution of Precision, and Positioning Techniques for use on and around the Moon

The National Aeronautics and Space Agency is examining several approaches to meet navigational requirements for spacecraft in lunar orbit, in transit to or from the moon, and for personnel on the lunar surface requiring an accurate, real-time, on-board navigation capability. This work addresses one possible solution to the navigation problem in the vicinity of the moon using a lunar satellite navigation system. Dilution of precision is the figure of merit used to determine if a candidate lunar satellite navigation system can meet accuracy specifications based on a given satellite constellation and the measurement types used. Ten satellite constellations, using two measurement types (direct ranging and time-difference-of-arrival), are analyzed for numerous user locations on the moon. Using terrestrial and Earth-orbiting assets to augment the lunar constellations is also investigated. Sensitivity analyses are accomplished to determine the effect on the position solution accuracy of additional measurements, reduced measurements, and different combinations of measurement types

The Diagnosis of Knee Pain

The knee is open to injury because it is designed for rapid action, not simply during its large excursion from extension to full flexion, but also lesser accommodative movements of rotation, tilt and glide. As if that were not enough, that highly developed but sometimes temperamental sesamoid, the patella, adds its own unique problems. The complexities of these movements are reflected in the subtleties of the structure of the knee. Regrettably they have also led to a proliferation of clinical tests and surgical repairs whose sophistication confuses rather than enlightens.Before enquiring about the characteristics of the painful knee the general characteristics of the patient should be assessed quickly. In children problems usually relate to patellar malalignment syndromes, possibly a discoid meniscus, and the aching discomfort produced by traction apophysitis such as Osgood-Schlatter's disease of the tibial tuberosity. After puberty girls are particularly likely to develop patellar pain, which may be associated with lateral subluxation of that bone. In the young woman the sources of such pain may be so prolix that the surgeon may do more harm than good if he operates. During adolescence and early adult life males are most likely to suffer from meniscal and ligamentous tears, often brought on by exertion or accidents during sport. A patient with an endomorphic physique usually has associated genu valgum and may present with medial ligament sprains and patello-femoral pain. Those with ligamentous laxity are also prone to sprains and patellar subluxation. The mesomorphic athlete is likely to injure the menisci, or may come in with significant tears of the ligaments and synovium

Structure of Equilenin at 100 K: an estrone related steroid

The structure of the estrone related steroid, Equilenin, C18H18O2 (systematic name 3-hydroxy-13-methyl-11,12,13,14,15,16-hexahydro-cyclopenta[a]phenanthren-17-one), has been determined at 100 K. The crystals are orthorhombic, P212121, and the absolute structure of the molecule in the crystal has been determined by resonant scattering [Flack parameter = 0.05 (4)]. The carbon atoms of the A and B rings, are coplanar with an r.m.s. deviation from planarity of 0.0104 A. The C ring has a sofa conformation while the D ring has an envelope conformation with the methine C atom as the flap. The keto oxygen and the methyl group are translated 0.78 A and 0.79 A, respectively, from the equivalent positions on 17β-estrone 3. In the crystal, molecules are linked by O—H・・・O hydrogen bonds forming 14 chains parallel to the c-axis direction