Extractability and Intracellular Localisation of Urea Cycle Enzym es from Rat Liver

Peer Reviewe

Nonlinear vertical oscillations of a particle in a sheath of a rf discharge

A new simple method to measure the spatial distribution of the electric field in the plasma sheath is proposed. The method is based on the experimental investigation of vertical oscillations of a single particle in the sheath of a low-pressure radio-frequency discharge. It is shown that the oscillations become strongly nonlinear and secondary harmonics are generated as the amplitude increases. The theory of anharmonic oscillations provides a good qualitative description of the data and gives estimates for the first two anharmonic terms in an expansion of the sheath potential around the particle equilibrium.Comment: 11 pages, 4 figure

Crystal structures of pure 3-(4-bromo-2-chlorophenyl)-1-(pyridin-4-yl) benzo [4, 5] imidazo [1, 2-d][1, 2, 4] triazin-4 (3H)-one and contaminated with 3-(4-bromophenyl)-1 …

The side product of the cyclocondensation reaction between ethyl benzimidazole-2-carboxylate and the nitrile imine of the corresponding hydrazonyl chloride, C20H11BrClN5O, crystallized in two crystal forms. Form (1) is a co-crystal of the target compound (without any chlorine substituent) and a side product containing a Cl atom in position 2 of the bromophenyl group, C20H12BrN5O·0.143C20H11BrClN5O. (2) contains the pure side product. The slightly different conformation of the ring systems leads to a different packing of (1) and (2), but both crystal structures are dominated by π–π interactions

Tetra­aqua­bis[3-(2-pyridylsulfan­yl)propionato N-oxide]nickel(II)

In the centrosymmetric title compound, [Ni(C8H8NO3S)2(H2O)4], the NiII ion, which lies on an inversion centre, is six coordinated by four water mol­ecules and two propionate O atoms from two 2-pyridylsulfanylpropionate N-oxide ligands, forming a slightly distorted octa­hedral geometry. An intra­molecular O—H⋯O hydrogen bond stabilizes the mol­ecular conformation. The crystal packing is consolidated by inter­molecular O—H⋯O and C—H⋯O hydrogen bonding

Tetra­kis{2,4-bis­[(1-oxo-2-pyridyl)­sulfanyl­methyl]mesitylene} acetone hemisolvate 11.5-hydrate

In the crystal structure of the title compound, 4C21H22N2O2S2·0.5C3H6O·11.5H2O, there are four crystallographically independent mol­ecules (A, B, C, D) with similar geometries, 11 water mol­ecules and a solvent acetone mol­ecule which is disordered with a water mol­ecule with occupancy factors of 0.5:0.5. The dihedral angles formed by the mesitylene ring with the two pyridyl rings are 82.07 (3) and 78.39 (3)° in mol­ecule A, 86.20 (3) and 82.29 (3)° in mol­ecule B, 81.05 (3) and 76.0 (4)° in mol­ecule C, 86.0 (3) and 80.9 (3)° in moleule D. The two pyridyl rings form dihedral angles of 41.17 (4), 64.01 (3), 81.9 (3) and 82.25 (3)° in mol­ecules A, B, C and D, respectively. The crystal structure is stabilized by inter­molecular O—H⋯O hydrogen bonds and possible weak C—H⋯π inter­actions. Some short intra­molecular S⋯O contacts are apparent [2.684 (4)–2.702 (4) Å]

1-(2,3,5,6-Tetra­methyl­benz­yloxy)-1H-benzotriazole

In the title compound, C17H19N3O, the benzotriazole ring is essentially planar, with a maximum deviation of 0.0069 (15) Å. The mean plane of the benzotriazole ring forms a dihedral angle of 13.16 (4)° with the mean plane of the benzene ring. The crystal packing is stabilized by π–π stacking inter­actions, with a centroid–centroid distance of 3.8077 (12) Å, together with weak C—H⋯π inter­actions. Mol­ecules are stacked along the a axis

Future challenges in colloid and interfacial science

This article deals with topics where I expect special future challenges, exemplifying these by experiments out of my own department. One area where I expect large progress also in view of many technical developments in the past concerns the understanding of the structure of fluid interfaces at the atomic level. It is shown by non-linear optical spectroscopies that the free water surface is ice-like and can be “liquefied” by ion adsorption. X-ray fluorescence from the interface demonstrates that ion binding is very specific which cannot be explained by existing theories. A second major area are nonequilibrium features, and one of the old and new ones here is nucleation and growth. This presentation concentrates on effects produced by ultrasound, a well-defined trigger of gas bubble formation. It exhibits high potential for chemistry at extreme conditions but with a reactor at normal conditions. It has special importance for treatment of surfaces that can be also manipulated via controlled surface energies. A third area will concern complex and smart systems with multiple functions in materials and biosciences. As next generation, I anticipate those with feedback control, and examples on this are self-repairing coatings