The title compound, C(17)H(10)O(2), is nearly planar, the maximum atomic deviation being 0.053 (2) Å. In the mol-ecule, an intra-molecular O-H⋯O hydrogen bond generates an S(6) ring motif. In the crystal, inversion-related mol-ecules are linked by pairs of weak C-H⋯O hydrogen bonds, forming dimers. π-π stacking is observed in the crystal structure, the closest centroid-centroid distance being 3...

Proof: Just pick g at random. For every particular 2 √ n-time algorithm A, the expected number of inputs on which A(x) = g(x) is one, and the probability that A computes g successfully on an at least 2−n/10 fraction of the total 2n inputs can be shown to be less than 2−2 −n/2 . But a 2 √ n algorithm can be described by about 2 √ n 2n/2 bits and so the total number of such algorithms is much sma...

M. Fauerbach,* M. J. Chromik, T. Glasmacher, 1,2 P. G. Hansen, 1,2 R. W. Ibbotson, 2 D. J. Morrissey, 2,3 H. Scheit, 1,2 P. Thirolf, 4 and M. Thoennessen 1,2 Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan 48824 National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan 48824 Department of Chemistry, Michigan State Uni...

In the title compound, C18H12O2, the non-H atoms are nearly coplanar, the maximum atomic deviation being 0.113 (2) Å. π-π stacking is observed in the crystal structure, the shortest centroid-centroid distance being 3.5983 (19) Å. The mol-ecular packing is further stabilized by weak C-H⋯O hydrogen bonds, forming an infinite chain along [100] and generating a C(6) motif.

Secure communication is the act of conveying information from a sender to a receiver, while simultaneously hiding it from everyone else. Secure communication is the oldest application of cryptography, and remains the centerpiece of cryptography to this day. After all, the word cryptography means “hidden writing” in Greek. So, secure communication is a natural place to start our study of cryptog...

The title compound, C29H44O2, was formed by treatment of 11-oxooleanolic acid under strong alkaline conditions. The absolute structure of the chiral mol-ecules could not be determined reliably from the diffraction data, but is known from other triterpenes. The asymmetric unit consists of two mol-ecules, 1 and 2. In both mol-ecules, rings A and B show chair conformations. The other rings show mi...

The structure of the title compound, C(25)H(27)NO, is a mono-ketone penta-cyclo-undecane (PCU) mol-ecule bearing a tertiary amine group. One of the methyl-ene groups in the PCU is disordered over two orientations with site-occupancy factors of 0.621 (7) and 0.379 (7).