Search

This paper describes the synthesis and characterization of core-shell structures, based on SnO2 and TiO2, for use in dye-sensitized solar cells (DSC). Atomic layer deposition is employed to control and vary the thickness of the TiO2 shell. Increasing the TiO2 shell thickness to 2 nm improved the device performance of liquid electrolyte-based DSC from 0.7% to 3.5%. The increase in efficiency originates from a higher open-circuit potential and a higher short-circuit current, as well as from an improvement in the electron lifetime. SnO2-TiO2 core-shell DSC devices retain their photovoltage in darkness for longer than 500 seconds, demonstrating that the electrons are contained in the core material. Finally core-shell structures were used for solid-state DSC applications using the hole transporting material 2,2',7,7',-tetrakis(N, N-di-p-methoxyphenyl-amine)-9,9',-spirofluorene. Similar improvements in device performance were obtained for solid-state DSC devices.

The total syntheses of the alkaloids eupolauridine-N-oxide (2) and eupolauridine-di-N-oxide (3) are described. The compounds 2 and 3 possess lower anticandidal activity than eupolauridine (1).

Among the aminoacyl derivatives of 2,7-diaminofluoren-9-one a few compounds were found capable of inducing interferon in the mouse when administered perorally. One of them, 2,7-bis[(diethylamino)acetylamino]fluoren-9-one exhibited an inducing activity comparable to that of 2,7-bis-(2-diethylaminoethoxy)-fluoren-9-one (tilorone). The synthesis of derivatives of fluorene, fluorenol, fluorenone, diaminobenzophenone, diaminiodiphenylmethane and benzidine, all of them with corresponding side chains, allowed to establish structural requirements for interferon inducing capability.

The possible destruction in the soil of PAH present in sewage sludge-garbage composts in considerable amounts has been studied under various conditions. Sandy and loamy soil were mixed with the compost and kept in a climate chamber at 20 degrees C, 25 degrees C and 28 degrees C with 30% and 80% relative moisture. One part of the samples was illuminated the other kept in the dark. Control samples with and without compost were sterilized. PAH determinations, bacterial counts on Moutonagar and counts of the actinomycetes were carried out in regular intervals. No influence of temperature, moisture or light could be demonstrated under the experimental conditions. No difference in the behaviour of PAH concentrations in sterilized and nonsterilized soil samples during the periods of experiment, no increase or decrease of PAH were found. There was no correlation between bacterial counts and PAH concentrations. The laboratory experiments confirmed the results of the field investigations.

Eight of fifteen Fluorenone-Azomethines without alkylating function have been found effective against the leukemia L 1210. Little modifications concerning the structure of the compounds caused loss of effectiveness. It seems remarkably that one corresponding derivative with a nitrogen mustard group (4) was ineffective. Correlations between chemical structure and biological effect have not yet been found.

A method for the determination of glyphosate and its major metabolite aminomethylphosphonic acid (AMPA) is described. With a detection limit of 0.02 microgram/l, the method suitably fulfills the requirements of the Swiss legislation (tolerance value of 0.1 micrograms/l water). The compounds are derivatized directly in the original water sample with 9-fluorenylmethyl chloroformate (FMOCC1) in order to obtain extractable and fluorescent derivatives. These are extracted with organic solvents and determined by HPLC using a fluorescence detector. Neither of the compounds could be detected in 151 tap water samples from the Canton of Berne.

Increased blood sugar levels may influence the refractive power of the lens in juvenile diabetics, and can lead to the rare true diabetic cataract ("snow-storm cataract"). Surplus glucose induces accumulation of the sugar alcohol within the cells, thus generating disturbances of the osmotic balance and finally causing cataract. The enzyme aldose reductase catalyzes the formation of sorbitol. Experiments with animals have shown that aldose reductase inhibitors can prevent the formation of such opacities with streptozotocin-induced diabetes in rats. Numerous aldose reductase inhibitors are now known, but we still have insufficient knowledge to determine whether systemic or local administration is preferable. The mechanisms reported here are not relevant with respect to the frequent occurrence of senile cataract in older diabetics, which has often been described.

(1) The mean content in benzypyrene (bp) of human pulmonary tissue amounts to 0.2 mug./100 g. of dry substance. As in all other organ tissues, however, the content differs with the age of the individual: in infants, we find maximum concentrations, in the medium age groups the levels decline and rise once more with increasing age. (2) No increase in the 3,4-benzpyrene levels (average: 0.2 mug./100 g. of dry substance) will be found in tissues with high cellular proliferative activity, such as exocrine and endocrine glands (pancreas, testicles, thyroid gland, adrenals, mammary glands, as well as bone marrow). (3) In human adipose tissue, as well as in that of pork and beef, the 3,4-benzpyrene levels are found to be exceedingly low. With values of 0.1 mug./100 g, the average concentrations lie markedly below the organ tissue levels. Hence, this class of noxious substances in not stored in the adipose tissue. (4) Both in man and in animals (pig, fowl), the 3,4-benzyprene concentrations consistently exceed the average values during early postnatal life. (5) This relatively high concentration of bp in early infancy is due to exogenous factors and is not the expression of biogenous synthesis, as has been demonstrated in examinations of the environmentally influenced embryonic development of the chick. Throughout the entire development of the embryo within the hen's egg, the benzpyrene levels remain constant. Only when the chickens have been hatched out do the benzyprene levels rise significantly. Thus, the low 3,4-benzpyrene levels detected in all human and animal organ tissues prove to be the result of the interplay of exogenous environmental loading and individual capability of eliminating this substance.

After the concentration of the polar organic compounds (= POCN), especially from the neutral fraction, was investigated in urban suspended particulates over a longtime period in Berlin (West) (March 1983-January 1984 at three emission measurement stations loaded by different sources) and some emissions were taken during 1985 from vehicle diesel-engines and private coal firing (domestic fuel) a comparison between all these measurements are given now. The following results were gained: The amount of the ether-extractable organic matter (= EEOM) was higher for the emission samples (less than or equal to 80% of the total suspended particulate matter = TPM) than for the emission measurements (less than or equal to 40% of the TPM). Most of the EEOM was found for particle sizes less than or equal to 1.5-2 micron aerodynamic diameter. Making further separation of the EEOM, then the neutral fraction (= NF) showed the highest percentage of about 60-90% (of the EEOM) for emission measurements and of 60-80% for emission measurements. The values of the acidic fraction (= AF) were with 5-30% (emissions) and 10-25% (emissions). Quite the same results were found for the basic fraction (= BF) with 1-20% (emissions) and 5-20% (emissions). Of the neutral fraction, further separation was done into aliphatic compounds (= AIP), polycyclic aromatic hydrocarbons (= PAH) and polar neutral organic compounds (= POCN). From these compounds, the aliphatics amounted to 30-40% (of the NF) for the vehicle emission measurements and to only 10-20% for the coal firing emissions. The percentages of the PAH and POCN varied and were quite similar with 10-50% (PAH) and 25-50% (POCN). For the emission measurements, the PAH amounted to lower values (5-30%) and the POCN to (30-60%). Some differences between the measurements were found in the gas chromatographic analysis of single PAH and POCN compounds. Then, for the vehicle samples (diesel engines and highway traffic tunnel) higher concentrations were found for perylene and coronene (of the PAH) and for mainly 1-nitropyrene (of the POCN) in comparison with coal firing emissions. There, we found higher concentrations for phenanthrene, benzo(a)pyrene and dibenz(a,h) anthracene (of the PAH) and for 9-fluorenone (of the POCN). The concentration of the nitro-groups containing substances (included in the POCN-fraction) amounted here generally to higher values in comparison with the vehicle emissions (except of 1-nitropyrene).(ABSTRACT TRUNCATED AT 400 WORDS)

Tilorone (free base) reacts with alkyl halides forming quaternary ammonium salts. Bis- as well as mono quaternary compounds (2 resp. 3) were synthesized. The tilorone-bis-methoiodide (2a) was converted to several carbonyl derivatives (4 and 5). All produced compounds did not show any cytostatic activity against the murine leukemias L 1210 and P 388 in vivo. Especially the bis-quaternary derivatives 2 were highly toxic in the mouse.

Using the conventional enrichment technique various bacteria were isolated capable of degrading simple aromatic hydrocarbons such as naphthalene, phenanthrene, and anthracene. One isolate had the capacity to co-oxidize fluorene, fluoranthene, and pyrene; the higher condensed aromatics, however, were not attacked. Ecological studies in soil percolators revealed that a variety of polycyclic aromatic hydrocarbons including benzo(a)-pyrene and benzo(a)anthracene were degraded by microbial activities.

The discussion about the possible consequences from the agricultural use of composted sewage sludge; which contains considerable amounts of polycyclic, aromatic hydrocarbons (PAH), caused us to investigate the normal concentrations of these substances in soil from agricultural land. In 50 soil samples, mainly from various parts of the Federal Republic of Germany the following 6 PAH were determined: fluoranthene, benzo(b)fluoranthene, benzo(k)fluoranthene, benzo(a)pyrene, benzo(ghi)perylene, indeno(1.2.3-cd)pyrene. In 74% of the samples benzopyrene concentration was between 2 and 50 microgram/kg, and the sum of the 6 compounds between 50 and 500 microgram/kg. No smaller values were found, and higher concentrations in most cases could be connected to some source of pollution.

A series of carbonyl derivatives of tilorone was synthetized by reaction with appropriate amino compounds, mainly hydrazines and hydrazides. The condensation products obtained were tested for cancerostatic activity against the murine leucaemia L 1210 and the Walker carcinosarcoma of the rat. Only three of the substances under investigation (1a, 5, 13) proved active against the Walker carcinosarcoma, one of which (5) being comparable to tilorone. No activity against L 1210 was observed, even tilorone exerted no effect. The reduction in activity against the Walker carcinosarcoma which resulted from the carbonyl substitution might be caused by a decrease in the ability to intercalate into DNA.