On the determination of accurate intensities from powder diffraction data. II. Estimation of intensities of overlapping reflections

Even the best least-squares algorithm to extract intensities from a powder diagram will not be able to determine the separate intensities of completely overlapping peaks. In this paper a new method (DOREES) is presented to determine these intensities more accurately by applying relations between structure factors derived from direct methods and the Patterson function. The intensities obtained from the least-squares fit are used as a starting set for DOREES. Comparative tests on both artificially generated and real data show that DOREES improves the intensity set considerably.

On the determination of accurate intensities from powder diffraction data. I. Whole-pattern fitting with a least-squares procedure

A new algorithm, direct intensity fitting, has been developed which performs a whole-pattern fitting for powder data. The algorithm is related to the fitting technique of Pawley [J. Appl. Cryst. 14, 357–361] but does not require start values for the intensities of the individual reflections. Comparative tests show that direct intensity fitting extracts more accurate intensities from a powder diffractogram and reduces the minimum peak distance for accurate data to half of the half-widths. The structure of the superconductor Ba2YCu3O8−x can be solved in a default direct-methods run with direct-intensity-fitting intensities extracted from a normal laboratory powder diffractogram.

[Rumania January 1990: acute medical deficits and chronic shortage--an evaluation at the site]

Between January 4 and 8, 1990, a medical delegation of the University Hospital Zurich (three surgeons, one OT-nurse) was sent to Bukarest. They escorted a large sending of surgical and pharmacological equipment. The assignment was 1. to evaluate the situation in the hospitals around the Bukarest area; 2. to determine the feasibility and the need of medical emergency support; 3. to assess the usefulness and practicability of medium-term relief. A total of 11 hospitals were visited in Bukarest, Pitesti, Racovita and Schitu-Golesti. It was found that 1. a sufficient number of doctors and medical personnel is available; 2. emergency aid is important regarding pharmaceuticals (local anesthetics, analgetics, insulin), infusions, dressing material, surgical instruments and external fixation equipment; 3. medium-term support is need for the complete medical equipment (syringes, injection and infusion sets, probes, suture material, etc.). Local medical literature and journals are worthless. Doctors long for high-quality medical books and periodicals. We can help!

Morphometric study of synaptic patterns in the rat caudate nucleus and hippocampus under haloperidol treatment

A morphometric study of the synapses on dendritic shafts and spines was performed in the rat caudate nucleus and the CAI area of the hippocampus under chronic haloperidol treatment. In the nucleus caudatus, the synaptic density on dendritic shafts increased by 83% and those on spines by 53%. Most of the parameters measured in axospinous synapses were significantly increased: the area of presynaptic axon terminals (20%), the number of mitochondria per axon terminal (51%), the length of active zone (11%), the area of postsynaptic density (23%), and the perimeter of postsynaptic density (12.5%). The area of postsynaptic spines showed no changes. In the synapses on dendritic shafts, the area of presynaptic terminals decreased (31%), the area of mitochondria per terminal decreased (40%), the length of active zone increased (14%), and other parameters were unchanged. There were no significant differences in the same parameters measured in the hippocampus. The data are discussed as morphological correlates of behavioral supersensitivity and dopamine D2 receptor up-regulation.