Doping of KDP single crystals with cerium: Growth and optical properties

The features of doping of KDP crystals with cerium ions and organocerium complexes with alizarin complexon and arsenazo III have been investigated. It is established that “direct” doping by introducing cerium salts into the initial solution cannot be implemented. The effect of organometallic complexes of cerium on the crystal growth has been studied. Organocerium complexes predominantly enter the prismatic or pyramidal growth sectors. It is shown that the complex arsenazo III + Ce blocks the growth of the prismatic sector. Cerium-doped KDP crystals exhibit a photoluminescence band peaking at the wavelength λ_max= 350 nm.     

Mental representations of important real-life decisions

Two studies investigated how decision makers characterize alternatives in important real-life decisions, which they themselves had made (to leave a partner, to choose an education and to choose a home). First, the participants indicated a very high degree of involvement in the decisions studied and about half of the participants gave maximum involvement ratings for the partner decision. Second, the results showed that concepts that are essential in most decision theories, such as, consequence, probability and value were important characteristics of the decisions. Third, emotion, positive and negative affect were also important characteristics. Fourth, value and emotion were uncorrelated. Fifth, the patterns of characteristics of decisions made in the past did not differ markedly from the characteristics given to future decisions. Principal component analyses were performed on the ratings of applicability of the different characteristics across participants for each decision situation. Three factors were extracted. There was one factor for positive affect/emotions and another factor for negative affect/emotions verified in oblique solutions. Thus, different scales are needed to represent emotion/affect components (and not bipolar scales) in real-life important decisions. The third factor represented the way in which a decision was represented (moving pictures dialogue etc.). An analysis restricted to the participants who rated 100% involvement showed an additional fourth factor with “what others would think”, “similar situations”, “values” and “money” as the most prominent characteristics. This points to the importance of controlling for participant involvement in studies of human decision making to enable generalizations to real-life decisions.     

Ultraviolet B Irradiation Modulates the Immune System of Fish (Rutilus rutilus, Cyprinidae). I. Phagocytes

Roach ( Rutilus rutilus ) were irradiated with a single dose of ultraviolet B (UVB) radiation (0.4 J/cm²) in order to study the effects of UVB on the nonspecific immune defense mechanisms of fish. Neutrophils and macrophages were isolated from the head kidney of fish on days 1–14 postirradiation. Both random and directed migration of neutrophils, studied by migration under agarose assay, were suppressed on day 1 after UVB irradiation. The respiratory burst of phorbol 12-myristate 13-acetatestimulated neutrophils and macrophages was also suppressed at days 1 and 2 after UVB irradiation. The suppression of migration and respiratory burst were restored or the responses were even enhanced later, but on the other hand spontaneous cytotoxicity of neutrophils toward ⁵¹chromium-labeled K562 target cells stayed suppressed throughout the 14 day follow-up. This study indicates that UVB radiation has the potential to suppress the functioning of phagocytes and to compromise the immune system of fish.     

Ultraviolet B irradiation modulates the immune system of fish (Rutilus rutilus, Cyprinidae). II: Blood

The effects of a single dose of ultraviolet B (UVB) radiation (0.4 J/cm2) on immunological functions by blood leukocytes and on hematological parameters was studied in roach (Rutilus rutilus), a teleostean fish. The respiratory burst of phorbol 12-myristate 13-acetate stimulated whole blood phagocytes increased significantly after UVB irradiation but spontaneous cytotoxicity of blood leukocytes toward 51chromium-labeled K562 target cells was not markedly altered. Differential cell counting revealed that UVB exposure significantly increased the proportion of granulocytes and significantly decreased the proportion of lymphocytes in the peripheral blood, whereas hematocrit and the total number of white and red blood cells were unchanged. Plasma cortisol concentration increased in UVB-exposed fish. Severe handling stress caused similar, although not as potent, effects on the measured parameters of fish blood as UVB irradiation. These observations suggest that in fish UVB brings about a stress response, which may account for the observed alterations in the immune parameters and leukocyte composition of blood. Exposure of fish to strong visible light induced no alterations in immunological or hematological parameters, making it unlikely that ultraviolet radiation mediates its effects through visual perception.     

On the two isomeric tris(perchlorothienyl)methyl radicals

The two isomeric tris(trichlorothienyl)carbinols have been synthesized. Upon treatment with acid the tris(trichlorothienyl)carbenium ions were formed, which upon reduction with iodide gave the tris(trichlorothienyl)methyl radicals, which were studied by epr-spectroscopy. The β-isomer, the tris(2,4,5-trichloro-3-thienyl)methyl radical, was much more stable than the α-isomer and showed great similarity to the perchlorotrityl radical.     

Nitration of dithieno[3,4-b:3′,2′-d]pyridine and dithieno[2,3-b:3′,2′-d]pyridine

The nitration of dithieno[3,4-b:3′,2′-d]pyridine ( 2 ) and dithieno[2,3-b:3′,2′-d]pyridine ( 3 ) has been studied. Nitration of 2 occurred in both positions of the c-fused thiophene ring, while 3 was predominantly substituted in the 2-position. The structures of the nitro derivatives were proven by extensive use of ¹H and ¹³C nmr spectroscopy.     

Synthesis of 5-cyclopropyluracil and 5-cyclopropylcytosine by the Pd(0)-catalyzed coupling reaction

5-Cyclopropyluracil and cyclopropylcytosine were prepared by the Pd(0)-catalyzed coupling reaction of 5-bromo-2,4-di(trimethylsilyloxy)pyrimidine and 5-bromo-2,4-O,N-bis-trimethylsilylcytosine with tributylstan-nylcyclopropane. The reactions also gave dehalogenated pyrimidine bases as by-products. Attempts to use 2,4-O,N-bis-trimethylsilyl-5-iodocytosine as the halide gave complete dehalogenation.     

The temperature-dependent red-shift of the visible absorption spectra of crystal violet in alcohol solutions

The visible absorption spectrum of the triphenylmethane dye, crystal violet, in various alcohol solutions at several temperatures has been recorded and subsequently analyzed by computer fitting. The observed spectral changes do not sustain either the earlier temperature-dependent absorption results of Lewis and co-workers or the concept of two ground-state species in equilibrium.     

Nitration of dithieno[3,2-b:3′,2′-d]pyridine and dithieno[3,2-b:3′,4′-d]pyridine

Nitration of dithieno[3,2-b:3′,2′-d]pyridine ( 4 ) and dithieno[3,2-b:3′,4′-d]pyridine ( 5 ) has been studied. Nitration of 4 occurred in both positions of the C ring, while 5 was predominantly substituted on the 3,4-fused ring. The structures of the nitro derivatives were proven by extensive use of ¹H and ¹³C nmr spectroscopy.     

Heterocyclic fused tropylium ions VII. On the synthesis of 9H-dithieno[2,1 -b:4,5-c′]tropylium fluoborate and 4H-dithieno[1,2-b:4,5-c′]tropylium fluoborate

9H-Dithieno[2,1 -b:4,5-c′]tropylium ion (III) and 4ii-dithieno[1,2-b:4,5-c′]tropylium ion (IV) have been synthesized by ring-closure of 1-(4-carboxy-3-thienyl)-2-(3′-thienyl)ethane (IX) and 1-(4-carboxy-3-thienyl)-2-(2′-thienyl)ethane (XVI), respectively, followed by bromination-debrom-ination to 9H-cyclohepta[2,1-b:4,5-c′] dithiophen-9-one (XI) and 4H-cyclohepta[1,2-b:4,5-c′]-dithiophen-4-one (XVIII), and finally by reduction and hydride transfer. The tropylium ions III and IV were less stable than the [b,b′]-fused isomers previously studied.