Contactless conductivity detector array for capillary electrophoresis

A CE system featuring an array of 16 contactless conductivity detectors was constructed. The detectors were arranged along 70 cm length of a capillary with 100 cm total length and allow the monitoring of separation processes. As the detectors cannot be accommodated on a conventional commercial instrument, a purpose built set‐up employing a sequential injection manifold had to be employed for automation of the fluid handling. Conductivity measurements can be considered universal for electrophoresis and thus any changes in ionic composition can be monitored. The progress of the separation of Na⁺ and K⁺ is demonstrated. The potential of the system to the study of processes in CZE is shown in two examples. The first demonstrates the differences in the developments of peaks originating from a sample plug with a purely aqueous background to that of a plug containing the analyte ions in the buffer. The second example visualizes the opposite migration of cations and anions from a sample plug that had been placed in the middle of the capillary.     

STM images of a large organic molecule adsorbed on a bare metal substrate or on a thin insulating layer: Visualization of HOMO and LUMO

An isomer of the methylterrylene molecule was adsorbed both on Cu(111) and on a NaCl bilayer deposited on Cu(111) and imaged by ultra high vacuum scanning tunneling microscopy at low temperature (5 K). On the bare metal surface, the STM images do not reveal any intramolecular resolution and do not depend on the applied tunnel bias. On the contrary, the images acquired at specific bias voltages for the molecule on the salt layer show a striking similarity with the spatial distribution of the electronic probability density in the highest occupied molecular orbital (HOMO) and in the lowest unoccupied molecular orbital (LUMO) of free methylterrylene. They are well reproduced by elastic scattering quantum chemistry calculations. These data provide a direct view of the hyperconjugative interaction between the methyl group and the frontier orbitals of terrylene.     

Distinguishing between small Arkani-Hamed-Dimopoulos-Dvali and Randall-Sundrum accelerator-generated black holes

In models with extra dimensions that accommodate a TeV-scale gravity, small black holes could be produced in near future accelerator experiments. Such small black holes, whose gravitational radius is much smaller than the characteristic size of extra dimensions can be very well described by asymptotically flat solutions, thus losing the information about the global geometry of the extra manifold. One might conclude that such small black holes would be indistinguishable in different scenarios. We argue that important differences still exist, especially regarding experimental signature in colliders, which may help us distinguish between the various extra dimensional scenarios. The main differences come from the fact that most of the models with the warped extra dimension have an additional discrete Z2 symmetry that makes the brane behave as if it were an infinite tension brane.     

Intermediate coupling model description of55Fe and57Fe

The properties of the negative parity states of⁵⁵Fe and⁵⁷Fe are investigated in the framework of the intermediate coupling model. In the model, a neutron or a quasineutron is coupled to anharmonic vibrations of the core. Anharmonicities of the vibrations are estimated through the observed properties of the core. Energy levels, spectroscopic factors and electromagnetic properties have been calculated. The results of the present calculations are also compared with available experimental results and other theoretical results. The model reasonably accounts for many of the properties of the low-lying states.     

Synthesis and antitumor evaluation of novel derivatives of 6-amino-2-phenylbenzothiazoles

Novel derivatives of 6-amino-2-phenylbenzothiazole bearing different substituents (amino, dimethylamino or fluoro) on the phenyl ring were prepared as the corresponding hydrochloride salts. 6-Nitro-2-(substituted-phenyl)benzothiazoles (1-6) were synthesized by condensation reactions of substituted benzaldehydes with 2-amino-5-nitrothiophenol. Nitro derivatives were reduced to the amino derivatives with SnCl(2)/HCl.Water soluble hydrochloride salts of 6-amino-2-(substituted-phenyl)benzothiazole (13-19)were prepared using concentrated or gaseous HCl. Compounds 13-19 were found to exert cytostatic activities against malignant human cell lines: cervical (HeLa), breast (MCF-7),colon (CaCo-2), laryngeal carcinoma (Hep-2), and normal human fibroblast cell lines (WI-38).