Excitation with effective subcycle laser pulses.

We have used laser pulses with a temporally shaped polarization to demonstrate the multiphoton excitation of the xenon 5g state within a subcycle of a laser pulse. Our polarization gated laser pulses are composed of circularly polarized sections at the leading and trailing edges of the pulse and of an experimentally defined linearly polarized central part. Only the linear part (the gate) of the pulse can excite neutral xenon in the 5g state. The transition cannot be driven with circularly polarized light because the number of photons needed would cause a violation of selection rules for the change of the magnetic quantum number. We show that the linearly polarized central part can be reduced to a subcycle pulse. This allows us to study excitation with an effective pulse as short as 2.3 fs at 800 nm. Electron imaging spectroscopy has been used to visualize the presence of excited states as a function of the pulse duration of the gate.

Wavelength and intensity dependence of short pulse laser xenon double ionization between 500 and 2300 nm.

The wavelength and intensity dependence of xenon ionization with 50 fs laser pulses has been studied using time-of-flight mass spectrometry. We compare the ion yield distribution of singly and doubly charged xenon with the Perelomov-Popov-Terent'ev (PPT) theory, Perelomov, Popov, and Terent'ev, Zh. Eksp. Teor. Fiz. 50, 1393 (1966) [Sov. Phys. JETP 23, 924 (1966)], in the regime between 500 and 2300 nm. The intensity dependence for each wavelength is measured in a range between 1 x 10(13) and 1 x 10(15) W/cm2. The Xe+-ion signal is in good agreement with the PPT theory at all used wavelengths. In addition we demonstrate that ionic 5s5p6 2S state is excited by an electron impact excitation process and contributes to the nonsequential double ionization process.

ETA and ETB receptor function in pancreatitis-associated microcirculatory failure, inflammation, and parenchymal injury.

The role of endothelin (ET)A and ETB receptor function in experimental pancreatitis is still not fully understood. Using a rat model of sodium taurocholate-induced pancreatitis and intravital microscopy, we therefore studied whether selective inhibition of ETA receptor function or combined ETA and ETB receptor blockade affects the development of pancreatitis-associated microcirculatory failure, inflammation, and parenchymal injury. Pretreatment with 10 mg/kg body wt of a combined ETA/B receptor antagonist, which is thought to mediate a simultaneous inhibition of both receptors, did not attenuate the pancreatitis-induced microcirculatory failure, inflammatory response, and parenchymal tissue injury. In contrast, pretreatment with a low concentration of the combined ETA/B receptor antagonist (4 mg/kg body wt), which predominantly inhibits the ETA receptor, revealed an improvement of some microcirculatory disorders and a significant attenuation of leukocyte recruitment and tissue injury. Furthermore, pretreatment with a selective ETA receptor antagonist (1 microg/kg body wt) almost abolished pancreatitis-associated capillary constriction, restored functional capillary density, and, consequently, improved overall nutritive perfusion. Importantly, the maintenance of an appropriate microcirculation by selective ETA receptor inhibition was accompanied by a significant attenuation of the inflammation-associated leukocytic response and by a marked reduction of parenchymal injury. Thus our study indicates that pancreatitis-associated development of microcirculatory failure, inflammation, and parenchymal injury is caused by ETs coupling onto the ETA receptor, which therefore may represent a promising target for novel strategies in the treatment of pancreatitis.

Correlation between double and nonresonant single ionization.

We performed simultaneous measurements of electrons and ions produced in Xe photoionization driven by an 800-nm, 100-fs laser pulse. The obtained energy and angular resolved electron spectra allow the identification of the electronic states populated during the ionization. Xe2+ ions appear at the same laser intensity as electrons emerging from a nonresonant 9-photon ionization process of Xe. Similar to optical tunneling ionization, the nonresonant ionization delivers low-energy electrons needed for the formation of Xe2+ by a backscattering process.

White-light-induced fragmentation of toluene.

We investigate the influence of continuum generation on the photofragmentation dynamics of the toluene molecule. By sending an 80-fs Ti:sapphire laser beam through a 2-mm-thick CaF2 plate we show that even moderately broadened laser frequency spectra considerably increase the degree of fragmentation, while it is nearly absent without continuum generation. The measured broadening of the frequency spectra and the known Raman-active vibrational modes of toluene afford an explanation in terms of a stimulated Raman scattering scheme, in which the molecule absorbs large amounts of vibrational energy.

The influence of zinc on the uptake and loss of cadmium and lead in the woodlouse, Porcellio scaber (Isopoda, Oniscidea).

Uptake of cadmium, lead, and zinc was studied in juvenile Porcellio scaber in feeding experiments over 5 months. The metals were offered separately and in different combinations and concentrations in the food. The ability of P. scaber to eliminate the accumulated metals was studied subsequently for 3 months on uncontaminated food. Characteristic patterns of accumulation are described for the three metals. The combination of lead and zinc resulted in only minor differences in these patterns. On the other hand, the combination of zinc and cadmium at high concentrations completely changed the accumulation patterns for both metals. Not only cadmium but also zinc was excreted by P. scaber exclusively when the animals had been contaminated with both metals. In contrast both metals were stored permanently when offered separately. Possible reasons for the interactions of cadmium and zinc are discussed.

Charge-state resolved above threshold ionization

Photoelectron energy resolved spectra recorded in coincidence with singly and doubly ionized atoms are reported for the interaction of xenon with 60 fs laser pulses at 800 nm and 1x10(14) W/cm(2). Double ionization contributions in the spectrum have been established. The appearance of a single ionization plateau in above threshold ionization is verified. A hotter electron distribution is found for the double ionization.

Antibacterial N-[omega,omega'-bis(alicyclic and aryl)-sec-alkyl]-1,3-diamino-2-propanol dihydrochloride salts.

A series of 14 antibacterial N-[omega,omega'-bis(cycloalkyl, bicyclo[2.2.1]heptyl, and substituted phenyl)-sec-alkyl]-1,3-diamino-2-propanol dihydrochloride salts were synthesized as potential topical antiseptics and disinfectants. Four derivatives which were particularly effective against Pseudomonas aeruginosa encompassed the three diverse ring-type substituents and an 8-n-pentadecyl moiety. The calculated Hansch hydrophobic parameter (pi) for the N-substituents of the more efficient compounds were in the range 7.0--9.0 and correlated with minimal inhibitory activity as a parabola for all of the products under the assay conditions. The potencies against Gram-positive and other Gram-negative bacteria were comparable to benzalkonium chloride and chlorhexidine.

Antibacterial N-[omega, omega'-bis(alicyclic and aryl)-sec-alkyl]poly(methylene)triamine and -tetramine hydrochloride salts.

A series of antibacterial N-(omega, omega'-(cycloalkyl, bicyclo[2.2.1]heptyl, and alkyl-substituted phenyl)-sec-alkyl]poly(methylene)triamine and -tetramine hydrochloride salts were synthesized in an effort to develop efficient, nonsystemic inhibitors, particularly for Pseudomonas aeruginosa. In the 1,5,9-triazanonane group, 3 of 16 compounds were effective at 8--10 micrograms/mL against pseudomonads. Efficiency appeared more dependent upon lipophilicity of the nitrogen substituent than other characteristics represented by the three types of rings. A parabolic relationship was observed for the entire set between the hydrophobic parameter, pi, of the lipoidal moiety and minimal inhibitory concentration. One of 16 tetramines, 1-[1,5-bis(3,3-dimethyl-2-norbornyl)-3-pentyl]-1,5,9,13-tetraazatridecane tetrahydrochloride (26f), ranked similarly. An additional two compounds in each series were superior to several commercial cationic detergents in the control of the Gram-negative bacteria. None was inhibitory at up to 200 micrograms/mL for Proteus vulgaris.

2-(Substituted phenyl)oxazolo[4,5-b]pyridines and 2-(substituted phenyl)oxazolo[5,4-b]pyridines as nonacidic antiinflammatory agents.

Some 2-(substituted phenyl)oxazolo[4,5-b]pyridines and 2-(substituted phenyl)oxazolo[5,4-b]pyridines have good antiinflammatory and analgesic activity. A few possess activity comparable to phenylbutazone or indomethacin without producing the irritation in the gastrointestinal tract that acidic antiinflammatory compounds cause.

Novel analgesic-antiinflammatory salicylates.

5-(2,4-Difluorophenyl)salicylic acid, diflunisal (25), is the best compound, in terms of both efficacy and safety, from over 500 salicylates investigated in our laboratories. It is a chemically distinct, nonacetylating salicylic acid, more active than aspirin as an analgesic and antiinflammatory agent and superior in duration of action and therapeutic index. Some recent clinical and biochemical observations are briefly discussed.

[The clinical significance of hyperuricemia for the prognosis of pregnancy toxemia]. / Klinische Bedeutung der Hyperurikämie zur Prognose bei EPH-Gestose.

This study demonstrates that uric acid serum levels are of importance in the prognosis of pregnancy complicated by hypertension. In early pregnancy the uric acid level probably is the most sensitive parameter to select the risk-prone pregnancies with EPH-gestosis to conduct the further course of pregnancy under medical care. Pregnant hypertensives with high uric acid levels develop more often retardation of the fetus, the incidence of eclampsia increases. In case of hypertension in pregnancy complicated by high uric acid levels careful monitoring and normalizing high blood pressure under medical observation improves the prognosis for fetus and mother.