[Costs of clinical ultrasound examinations - an economical cost calculation and analysis]. / Kosten von Ultraschalluntersuchungen im Krankenhaus - das Modell einer Deckungsbeitragsrechnung.

PURPOSE: The aim of the study was to calculate the costs for clinical ultrasound examinations in Germany under defined economical aspects in a multicenter setting. MATERIALS AND METHODS: There are fixed and variable costs for all common ultrasound examinations calculated under distinct scenarios for utilization and equipment quality (ultrasound systems classification concerning to DEGUM, German Ultrasound Society). RESULTS: Over 5 years (on average 2007 - 2011) depending on utilization and quality, the basic sonography costs were 131.30 - 171.39 Euros for contrast-enhanced ultrasound (CEUS) and 57.06 - 77.10 Euros for ultrasound guided biopsy per examination. The costs were calculated at 54.84 - 74.88 Euros for endosonography of the lower GI tract, at 79.20 - 109.27 Euros for the upper GI tract without biopsy and at 226.18 - 367.97 Euros with biopsy depending on the needle used. The costs were 34.58 - 47.01 Euros for basic transthoracic echocardiography, 100.04 - 112.20 Euros for CEUS, and 106.15 - 134.29 Euros for the transesophageal approach. CONCLUSION: Cost calculation under defined economical aspects leads to cost transparency for clinical ultrasound examinations. Echocardiography costs were calculated like this for the first time in Germany. Calculation based on fixed and variable cost aspects as well as using distinct scenarios enables prospective planning of resources and investment. The analysis points out deficits in the reimbursement of ultrasound examinations in Germany.

Patterns of peroxidative ethane emission from submerged rice seedlings indicate that damage from reactive oxygen species takes place during submergence and is not necessarily a post-anoxic phenomenon.

Using ethane as a marker for peroxidative damage to membranes by reactive oxygen species (ROS) we examined the injury of rice seedlings during submergence in the dark. It is often expressed that membrane injury from ROS is a post-submergence phenomenon occurring when oxygen is re-introduced after submergence-induced anoxia. We found that ethane production, from rice seedlings submerged for 24-72 h, was stimulated to 4-37 nl gFW(-1), indicating underwater membrane peroxidation. When examined a week later the seedlings were damaged or had died. On de-submergence in air, ethane production rates rose sharply, but fell back to less than 0.1 nl gFW(-1) h(-1) after 2 h. We compared submergence-susceptible and submergence-tolerant cultivars, submergence starting in the morning (more damage) and in the afternoon (less damage) and investigated different submergence durations. The seedlings showed extensive fatality whenever total ethane emission exceeded about 15 nl gFW(-1). Smaller amounts of ethane emission were linked to less extensive injury to leaves. Partial oxygen shortage (O(2) levels <1%) imposed for 2 h in gas phase mixtures also stimulated ethane production. In contrast, seedlings under anaerobic gas phase conditions produced no ethane until re-aerated: then a small peak was observed followed by a low, steady ethane production. We conclude that damage during submergence is not associated with extensive anoxia. Instead, injury is linked to membrane peroxidation in seedlings that are partially oxygen deficient while submerged. On return to air, further peroxidation is suppressed within about 2 h indicating effective control of ROS production not evident during submergence itself.

Kinetics of ethanol and acetaldehyde release suggest a role for acetaldehyde production in tolerance of rice seedlings to micro-aerobic conditions.

BACKGROUND AND AIMS: This paper examines the basis of the greater tolerance of an indica rice cultivar FR13A to complete submergence compared with relatively intolerant japonica rice CT6241. We study whether this superior tolerance is related to its greater tolerance to O2 shortage and to an ability to run a more favourable rate of alcoholic fermentation during and after O2 deprivation. METHODS Fermentation products were analysed using sensitive laser-based photoacoustics at high time resolution to establish patterns and rates of ethanol and acetaldehyde emission by intact rice seedlings exposed to micro-aerobic (0.05-0.5 % O2) or zero O2 supply, and also during their return to air. Oxygen and CO2 emission or uptake was also quantified. KEY RESULTS: In the dark, no acetaldehyde and ethanol emission was observed until external O2 concentration in a gas phase decreased to

[Ocular hemodynamics in normal tension glaucoma: effect of bimatoprost]. / Okuläre Hämodynamik beim Normaldruckglaukom: Effekte von Bimatoprost.

BACKGROUND: Altered ocular perfusion plays a role in the pathophysiology of normal tension glaucoma. Prostaglandin-like substances are very effective in lowering intraocular pressure. Less data are available regarding the influence of these compounds on ocular perfusion. In the present study the effects of bimatoprost, which has recently been shown to increase the vascular tone of ciliary arteries in vitro, on the blood flow velocity are investigated. PATIENTS AND METHODS: n = 9 eyes from 9 normal tension glaucoma patients were subjected to color Doppler imaging (CDI) before and during a 3 - 5 week therapy with bimatoprost. RESULTS: Bimatoprost reduces intraocular pressure from 14.0 +/- 0.4 to 11.0 +/- 0.5 mmHg (n = 9; P < 0.001). Systolic as well as diastolic blood flow velocities, resistive index (RI) and pulsatility index (PI), measured by CDI, were unaltered in the presence of bimatoprost. DISCUSSION: Bimatoprost does not influence blood flow velocities in the retrobulbar vessels. The in vitro observation of increased vascular tone in the presence of bimatoprost seems not to be relevant for ocular hemodynamics.

Photon tracking in a multilayer tissue model.

A multilayer tissue description was employed in a Monte Carlo simulation of light-tissue interaction to study photon travel through skin. Paths of photons returning to the tissue surface at a certain range from the point of entry (emitter-detector spacing) were collected. The simulation demonstrates that highly absorptive discrete layers (e.g., containing melanin or blood) tend to channel photons away. As a result, the dependence of mean depth of photon penetration on wavelength is quite different from the predictions of a homogeneous tissue model. The impact upon our understanding of pulse oximetry is discussed.

Dynamic aspects of alcoholic fermentation of rice seedlings in response to anaerobiosis and to complete submergence: relationship to submergence tolerance.

Rice plants are severely damaged by complete submergence. This is a problem in rice farming and could be the result, in part, of tissue anoxia imposed by a reduced availability of oxygen. To investigate this possibility we monitored alcoholic fermentation products as markers for tissue anaerobiosis using sensitive laser-based spectroscopy able to sense ethanol and acetaldehyde down to 3 nl l(-1) and 0.1 nl l(-1), respectively. Acetaldehyde emission began within 0.5 h of imposing an oxygen-free gas phase environment followed closely by ethanol. As treatment progressed, ethanol output increased and came to exceed acetaldehyde emission as this stabilized considerably after approx. 3 h. On re-entry of air, a sharp post-anaerobic peak of acetaldehyde production was observed. This was found to be diagnostic of a preceding anoxic episode of 0.5 h or more. When anaerobiosis was lengthened by up to 14 h, the size of the post-anaerobic acetaldehyde outburst increased. After de-submergence from oxygen-free water, a similarly strong but slower post-anaerobic acetaldehyde upsurge was seen, which was accompanied by an increase in ethanol emission. Light almost, but not completely, eliminated fermentation in anaerobic surroundings and also the post-anaerobic or post-submergence peaks in acetaldehyde production. All photosynthetically generated oxygen was consumed within the plant. There was no substantial difference in acetaldehyde and ethanol output between FR13A and the less submergence-tolerant line CT6241 under any submergence treatment. In some circumstances, submergence damaged CT6241 more than FR13A even in the absence of vigorous fermentation. We conclude that oxygen deprivation may not always determine the extent of damage caused to rice plants by submergence under natural conditions.

Simultaneous determination of the (2)h/(1)h, (17)o/(16)o, and (18)o/(16)o isotope abundance ratios in water by means of laser spectrometry.

We demonstrate the first successful application of infrared laser spectrometry to the accurate, simultaneous determination of the relative (2)H/(1)H, (17)O/(16)O, and (18)O/(16)O isotope abundance ratios in water. The method uses a narrow line width color center laser to record the direct absorption spectrum of low-pressure gas-phase water samples (presently 10 µL of liquid) in the 3-µm spectral region. It thus avoids the laborious chemical preparations of the sample that are required in the case of the conventional isotope ratio mass spectrometer measurement. The precision of the spectroscopic technique is shown to be 0.7‰ for δ(2)H and 0.5‰ for δ(17)O and δ(18)O (δ represents the relative deviation of a sample's isotope abundance ratio with respect to that of a calibration material), while the calibrated accuracy amounts to about 3 and 1‰, respectively, for water with an isotopic composition in the range of the Standard Light Antarctic Precipitation and Vienna Standard Mean Ocean Water international standards.

Introduction.

During the last decade the use of laser radiation has grown far beyond its traditional role as a convenient, bright and spectrally narrow source of light. In particular, the coherence properties of the radiation have been put to use for very detailed and fine work in spectroscopy, collision dynamics and the manipulation of both the internal structure and the center of mass motion of atoms and molecules. These are the key words describing the work program of the research network "Laser Controlled Dynamics of Molecular Processes and Applications (ERB-CHR-XTC-94-0603),' established by the European Union under the program "Human Capital and Mobility (HCM)' with the intent of sending young researchers (postdocs and students) across national borders within the European Union.

[Time requirements of medical and non-medical personnel for ultrasound studies]. / Zeitaufwand von ärztlichen und nichtärztlichen Mitarbeitern für Ultraschalluntersuchungen.

To assess the time needed for ultrasound examinations for physicians and assistants we carried out a survey among members of the German Association of Ultrasound in Medicine (DEGUM) in hospitals and practices. The physician's examination time for the investigation of the upper abdomen and kidneys was 12.3 min with additional time for preparation (2.9 min), for work up (2.3 min) and written documentation (3.6 min), together 21.3 min. The examination times in practices (18.9 min) are shorter than in ultrasound labs in hospitals. Assistants in ultrasound laboratories need for organisation, upkeep of equipment, to filing the images in archives etc. medium 15.2 min per patient. Assistants with exclusive employment in the ultrasound laboratory need 17.6 min (4-57 min), whereas assistants employed in the ultrasound laboratory and other departments need 12.7 min (1.6-31 min). In internal practices the desired time is 7.9 min (3.5-20 min). Because of the different organisation in the ultrasound laboratories in several hospitals and in practices a comparison of times needed by assistant personnel (or, in many cases, by the physicians who perform such work themselves) is very difficult. The examination time really needed by physicians and the time for assistant personnel are shorter than presumed earlier, but are longer than estimated in the recent discussion about money saving in medicine.

Multicomponent trace-gas analysis by three intracavity photoacoustic cells in a CO laser: observation of anaerobic and postanaerobic emission of acetaldehyde and ethanol in cherry tomatoes.

Three serial photoacoustic cells are employed within the cavity of a liquid-nitrogen-cooled CO laser to monitor on-line trace-gas concentrations. Multicomponent gas analysis is performed on sequential repetitive measurements of ethylene, acetaldehyde, CO2, ethanol, and H2O. To demonstrate the high sensitivity of the laser photoacoustic detector for the biologically interesting gases, acetaldehyde (0.1-parts per billion in volume detection limit) and ethanol (10 parts per billion in volume), we follow the time-dependent release by cherry tomatoes during changing aerobic-anaerobic conditions.

Motion in a stochastic layer described by symbolic dynamics.

The motion in the stochastic layer surrounding an island can be studied by using the standard map: This problem is of direct relevance to the diffusion of magnetic field lines in a tokamak. In a previous work it was shown that this process can be adequately modelled by a continuous time random walk (CTRW) describing transitions of the running point between three basins representing, respectively, trapped motion around the island, and passing motion above or below the island. The sticking property of the island deeply modifies the nature of the transport process, leading to subdiffusive behavior. In the present work it is shown that the motion can be analyzed in terms of a symbolic dynamics which leads to the possibility of an automatic measurement of the data necessary for the construction of the CTRW. The logical features of the procedure are described, and the method is applied to an analysis of long time series, thus completing the results of the previous work. (c) 1998 American Institute of Physics.

Interaction of Vibrational Fundamental and Combination States of Ethylene in the 3 &mgr;m Region

High-resolution IR spectra of ethylene cooled in a molecular jet have been investigated revealing perturbations of some rovibrational lines of nu9 and nu11 fundamentals due to resonant Coriolis interactions. In the range of J up to 4, two combination states, nu3 + nu8 + nu10 and nu6 + nu8 + nu10, were shown to be the strongest local perturbers. Borrowing of dipole moments due to third-order Coriolis interaction was observed and the appropriate rovibrational lines of the combination bands were assigned. Modeling of the observed spectra was achieved using the power expansion of the Hamiltonian and the dipole moment operator in the frame of tensorial formalism of the symmetry point group of the molecule. The coupling of 32 vibrational combination states with the nu9 and nu11 fundamentals via cubic anharmonicity and Coriolis interaction was considered. Many new coupling parameters have been determined. Copyright 1997 Academic Press. Copyright 1997Academic Press

Dynamics of Acetaldehyde Production during Anoxia and Post-Anoxia in Red Bell Pepper Studied by Photoacoustic Techniques.

Acetaldehyde (AA), ethanol, and CO2 production in red bell pepper (Capsicum annum L.) fruit has been measured in a continuous flow system as the fruit was switched between 20% O2 and anaerobic conditions. Minimum gas phase concentrations of 0.5 nL L-1, 10 nL L-1, and 1 mL L-1, respectively, can be detected employing a laser-based photoacoustic technique. This technique allows monitoring of low production rates and transient features in real time. At the start of anaerobic treatment respiration decreases by 60% within 0.5 h, whereas AA and ethanol production is delayed by 1 to 3 h. This suggests a direct slow-down of the tricarboxylic acid cycle and a delayed onset of alcoholic fermentation. Reexposure of the fruit to oxygen results in a 2- to 10-fold upsurge in AA production. A short anoxic period leads to a sharp transient peak lasting about 40 min, whereas after numerous and longer anoxic periods, post-anoxic AA production stays high for several hours. High sensitivity of the fruit tissue to oxygen is further evidenced by a sharp decrease in post-anoxic AA production upon an early return to anaerobic conditions. Ethanol oxidation by the "peroxidatic" action of catalase is proposed to account for the immediate post-anoxic AA upsurge.

On-line monitoring of nitrogenase activity in cyanobacteria by sensitive laser photoacoustic detection of ethylene.

A new and extremely sensitive method for measuring nitrogenase activity through acetylene reduction is presented. Ethylene produced by nitrogenase-mediated reduction of acetylene is detected by using laser photoacoustics (LPA). This method possesses a detection limit making it 3 orders of magnitude more sensitive than traditional gas chromatographic analysis. Photoacoustic detection is based on the strong and unique absorption pattern of ethylene in the CO(inf2) laser wavelength region (9 to 11 (mu)m). The high sensitivity allowed on-line monitoring of nitrogenase activity in a culture of the heterocystous cyanobacterium Nodularia spumigena, which was isolated from a water bloom in the Baltic Sea. This setup makes it unnecessary to take subsamples from the culture and avoids long incubations in sealed vials. The fast response of the LPA technique allows measurement of real-time dynamic changes of nitrogenase activity. The method was used to analyze in vivo saturation of nitrogenase by acetylene in N. spumigena. It is demonstrated that 20% acetylene does not saturate nitrogenase and that the degree of saturation depends on light intensity. With concentrations of acetylene as low as 2.5% it is possible to assess the degree of saturation and to extrapolate to total nitrogenase activity. In N. spumigena nitrogenase activity becomes independent of light intensity above 20 to 80 (mu)mol of photons m(sup-2) s(sup-1) at 20% O(inf2).

Multiple-Photon Dynamics in Molecules: A New Approach to High Resolution Spectroscopy of Highly Excited Vibrational States

Multi-photon transitions with two simultaneously interacting IR laser fields lead to final excited states with frequencies nnu = n1nu1 + n2nu2, with n the total number of photons absorbed and (n, n1, n2) = (2, 1, 1), (3, 2, 1), (4, 1, 3), etc. The nature of the actual transition is determined by shift measurements, where the lasers are frequency-tuned by deltanui in opposite directions keeping the sum frequency, nnu, resonant with the molecular transition. This technique opens a new spectral range for multi-photon transitions and a unique identification of the observed features. For n1 and n2 both positive the excitation will lead to a "normal" up-up multi-photon transition. Many three- and four-photon transitions in the nu3 vibrational ladder of SF6 could be resolved with a resolution of 1 MHz, as well as four new two-photon transitions. As long as n1 + n2 >/= 0, one of the two ni may be negative resulting in an, e.g., up-down excitation pathway with its particular selection rules. The up-down excitations are demonstrated both for one- and two-photon transitions using the frequency shift technique. The different possible excitation schemes which meet the resonance condition for these transitions lead to interference effects and local couplings to highly excited states. Changes in resonance frequency for a one-photon transition (n = 1), due to these effects, are demonstrated. Evidently, the radiative coupling of participating levels to high-lying or quasi-continuum states may drastically change for different deltanui leading both to ac Stark shift and transition probability variations.

The Ethylene Hot Band Spectrum near 3000 cm-1

A new hot band spectrum of ethylene has been recorded from 2970 to 3015 cm-1 at low rotational temperatures in a seeded molecular jet, using vibrational energy transfer from SF6 to C2H4. An IR-IR double resonance technique has been applied to pump the lower states and subsequently probe the hot bands. Two new hot bands, nu10 + nu11 - nu10 and nu7 + nu11 - nu7, have been found. The weak hot band starting from nu7 has been identified by direct labeling of some rotational levels in the nu7 manifold. High resolution FTIR spectra at ambient and at elevated temperatures have been recorded, too; it has thus become possible to extend the analysis to higher rotational quantum numbers. The previously analyzed nu9 + nu10 level has been reinvestigated and a b-type Coriolis interaction with the nearby nu7 + nu11 state has been observed. Rotational energy levels of nu7 + nu11 and of nu9 + nu10 have been fitted simultaneously, taking into account the local perturbations due to five dark states. From the shift of all K not equal 0 levels to higher frequencies in the nu10 + nu11 state, a global a-type Coriolis interaction with nu8 + 2nu12 has been identified.

Intracavity CO laser photoacoustic trace gas detection: cyclic CH(4), H(2)O and CO(2) emission by cockroaches and scarab beetles.

A liquid-nitrogen-cooled CO laser and an intracavity resonant photoacoustic cell are employed to monitor trace gases. The setup was designed to monitor trace gas emissions of biological samples on line. The arrangement offers the possibility to measure gases at the 10(9) by volume (ppbv) level (e.g., CH(4), H(2) O) and to detect rapid changes in trace gas emission. A detection limit of 1 ppbv for CH(4) in N(2) equivalent to a minimal detectable absorption of 3 × 10(-9) cm(-1) can be achieved. Because of the kinetic cooling effect we lowered the detection limit for CH(4) in air is decreased to 10 ppbv. We used the instrument in a first application to measure the CH(4) and H(2) O emission of individual cockroaches and scarab beetles. These emissions could be correlated with CO(2) emissions that were recorded simultaneously with an infrared gas analyzer. Characteristic breathing patterns of the insects could be observed; unexpectedly methane was also found to be released.