Nonlinear Propagation and Filamentation on 100 Meter Air Path of Femtosecond Beam Partitioned by Wire Mesh.

High-intensity (∼1 TW/cm2 and higher) region formed in the propagation of ∼60 GW, 90 fs Ti:Sapphire laser pulse on a ∼100 m path in air spans for several tens of meters and includes a plasma filament and a postfilament light channel. The intensity in this extended region is high enough to generate an infrared supercontinuum wing and to initiate laser-induced discharge in the gap between the electrodes. In the experiment and simulations, we delay the high-intensity region along the propagation direction by inserting metal-wire meshes with square cells at the laser system output. We identify the presence of a high-intensity region from the clean-spatial-mode distributions, appearance of the infrared supercontinuum wing, and occurrence of the laser-induced discharge. In the case of free propagation (without any meshes), the onset of the high-intensity zone is at 40-52 m from the laser system output with ∼30 m extension. Insertion of the mesh with 3 mm cells delays the beginning of the high-intensity region to 49-68 m with the same ∼30 m extension. A decrease in the cell size to 1 mm leads to both delay and shrinking of the high-intensity zone to 71-73 m and 6 m, respectively. Three-dimensional simulations in space confirm the mesh-induced delay of the high-intensity zone as the cell size decreases.

Ursodeoxycholic acid dose-dependently improves liver injury in rats fed a methionine- and choline-deficient diet.

AIM: The data on the beneficial effect of ursodeoxycholic acid (UDCA) in non-alcoholic steatohepatitis (NASH) are controversial. The difference of opinion is connected with UDCA dosage to be used. Therefore, we evaluated the dose-dependent efficacy of UDCA in experimental NASH. METHODS: Male Wistar rats were fed the methionine- and choline-deficient (MCD) diet for 10 weeks. Rats were administrated UDCA (10, 20, 40 and 80 mg/kg bodyweight intragastrically) after 6 weeks of the MCD diet. RESULTS: Animals fed the MCD diet developed severe steatohepatitis. Treatment with UDCA dose-dependently decreased liver damage, but only high-dose UDCA (80 mg/kg) significantly diminished ultrastructural changes in addition to preventing steatosis, ballooning and inflammatory changes in the liver. The activities of serum marker enzymes and the content of liver triglyceride and blood glucose were increased in MCD diet-fed rats, but decreased in all the UDCA-treated groups. Serum insulin concentration was decreased whereas the quantitative insulin sensitivity check index did not changed in MCD diet-fed groups. Serum tumor necrosis factor-α content was strongly increased after MCD diet and normalized in the UDCA-treated rats, with the most pronounced effect in the highest dose groups, 40 and 80 mg/kg. The contents of endogenous ethanol in blood and intestinal mucus were increased in MCD diet-fed rats which were significantly lowered by UDCA (40 and 80 mg/kg per day). CONCLUSION: The present data demonstrate a beneficial effect of UDCA that manifested by the decrease of liver steatosis, inflammatory signs and serum tumor necrosis factor-α content especially of the highest 40 and 80 mg/kg day doses.

Chlorin e6-cholesterol conjugate and its copper complex. Simple synthesis and entrapping in phospholipid vesicles.

Synthesis of 13'[(cholest-5-en)-3beta-yloxyethoxycarbamoyl]-chlorin e6 starting from methylpheophorbide and 3beta(2-hydroxy)-ethoxycholest-5-ene is presented, as well as the preparation of related copper complex. Both conjugates obtained may be simply incorporated in phosphatidyl choline vesicles.