Expectation values of single-particle operators in the random phase approximation ground state

We developed a method for computing matrix elements of single-particle operators in the correlated random phase approximation ground state. Working with the explicit random phase approximation ground state wavefunction, we derived practically useful and simple expression for a molecular property in terms of random phase approximation amplitudes. The theory is illustrated by the calculation of molecular dipole moments for a set of representative molecules.Comment: Accepted to J.Chem.Phy

The Assessment of Environmental Impacts at Nuclear Power Generating Stations

The Federal actions that are required with regard to nuclear power stations are the granting of a construction permit and later the issuance of a license to operate the station. Since the Atomic Energy Commission (AEC) is responsible for these actions, the Commission is also responsible for preparation of an environmental statement on the proposed actions. The National Laboratories including the one at Oak Ridge are used as part of the staff in preparing the statements. The staff makes an independent determination of the plant effluents and their dispersions. The impact of these and plant construction on the environment are assessed by the staff. Alternatives to the proposed plant are similarly evaluated as are alternative subsystems such as the proposed waste heat removal system. Finally the environmental costs are compared with the benefits. A number of assessments have resulted in required changes in heat removal systems, chemical treatment procedures and radioactive waste systems to reduce the impacts to an acceptable level. The benefits of the modified stations have been shown to outweigh the environmental costs

Solvent mediated centric/non-centric polymorph pairs of an indole derivative: subtle variation of C-HO hydrogen bonds and C-Hπ interactions

Centric (P21/n) and non-centric (P21) polymorphic pairs of biologically active 1-(4-fluorophenyl)-6,6-dimethyl-2-phenyl-1,5,6,7-tetrahydro-4H-indol-4-one crystallized from different solvents have been elucidated via single crystal and powder X-ray diffraction studies, morphological observations and calorimetric measurements. C-H...O hydrogen bonding and weak intermolecular C-H...π interactions generate distinct packing features in the two forms

Observation of a reversible isomorphous phase transition and an interplay of "sigma-holes'' and "pi-holes'' in Fmoc-Leu-psi[CH2-NCS]

Fmoc-Leu-psi[CH2NCS] undergoes a reversible isomorphous phase transition upon cooling. The crystal structure at 100 K displays a short N=C=S center dot center dot center dot N=C=S intermolecular interaction, which has been characterized based on experimental charge density analysis, as a stabilizing interaction with both sigma-holes and pi-holes acting cooperatively

Magnetoresistance in ordered and disordered double perovskite oxide, Sr2_2FeMoO6_6

We have prepared crystallographically ordered and disorder specimens of the double perovskite, Sr$_2$FeMoO$_6$ and investigated their magnetoresistance behaviour. The extent of ordering between the Fe and Mo sites in the two samples is determined by Rietveld analysis of powder x-ray diffraction patterns and reconfirmed by M\"{o}ssbauer studies. While the ordered sample exhibits the sharp low-field response, followed by moderate changes in the magnetoresistance at higher fields, the disordered sample is characterised by the absence of the spectacular low-field response. We argue that the low field response depends crucially on the half-metallic ferromagnetism, while the high-field response follows from the overall magnetic nature of the sample, even in absence of the half-metallic state.Comment: accepted in Solid State Communicatio

General relationships of mammalian orders and evolutionary development of primates inferred from best-fit α-globin phylogenies

A best-fit α-globin phylogeny was identified by means of a global minimization approach from among the topologies generated by a parsimony strategy. Zip parsimony method was used to derive a set of near-parsimonious trees. For each of these topologies, a difference matrix was computed; and the topology with the best goodness of fit with the original matrix was retained as the best tree. Based on this phylogenetic scheme inter-relationships among eutherian orders and the evolutionary development of primates has been discussed

Export of proteins across membranes: the helix reversion hypothesis

A model is presented which explains the biological role of the leader peptide in protein export. Along the lines of this model, the conformational changes of a protein with environment serves as a general mechanism for translocation. The leader peptide in the cytoplasm takes a hairpin like conformation which reverts to an extended helix upon integration into the membrane. The essential features of this model are in accord with recent results of protein export

N-Phenylethyl-N'-[3-(trifluoromethyl)phenyl]thiourea

The title compound, C16H15F3N2S, is a biologically active anti-implantation agent. The dihedral angle between the phenyl and trifluoromethylphenyl rings is 15.9 (2)°. The crystal structure is stabilized by intermolecular N-HS hydrogen bonds, forming dimers

4-(2-Methylprop-2-enyl)-1-[3-(trifluoromethyl)phenyl]thiosemicarbazide

The title compound, C12H14F3N3S, is a biologically active anti-implantation agent. Its crystal structure is stabilized by intermolecular N-H...S hydrogen bonds, which form dimers in a head-to-tail arrangement and link them into a polymeric chain

Isomeric triazines exhibit unique profiles of bioorthogonal reactivity.

Expanding the scope of bioorthogonal reactivity requires access to new and mutually compatible reagents. We report here that 1,2,4-triazines can be tuned to exhibit unique reaction profiles with biocompatible strained alkenes and alkynes. Computational analyses were used to identify candidate orthogonal reactions, and the predictions were experimentally verified. Notably, 5-substituted triazines, unlike their 6-substituted counterparts, undergo rapid [4 + 2] cycloadditions with a sterically encumbered strained alkyne. This unique, sterically controlled reactivity was exploited for dual bioorthogonal labeling. Mutually orthogonal triazines and cycloaddition chemistries will enable new multi-component imaging applications