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Integrated geophysical analysis using different methods along with a priori information from wells, is a proven approach to investigate the geology and the petro-physical characteristics of subsoil. We collected seismic and geoelectric data in an area located on the Adriatic coast in North-Eastern Italy, aimed at characterizing the quaternary sediments and the shallow geological structures. Compressional and shear-wave data provided information about geometry and velocity of the quaternary sedimentary succession, while geoelectric data provided information about the resistivity in the shallower formation, which strongly depends on the presence of groundwater (brine) and on its salinity. Clustering analysis allowed us to subdivide the study area into subdomains showing similar values of resistivity and compressional- and shear-wave velocity, enabling for a better interpretation of the processed seismic sections. Then, we calculated the petro-physical properties of the investigated sediments, i.e., brine saturation and resistivity, porosity, and clay content, for each cluster. This inverse problem involves rock-physics theories and an optimization algorithm based on the simulated annealing global-search method. The results, validated using borehole stratigraphy, provided information about the salty water wedge intrusion.

An analysis of multi-channel seismic reflection data integrating reflection tomography, pre-stack depth migration, AVO analysis, seismic modelling and seismic attribute analysis was used to investigate the Miocene - Quaternary stratigraphy of the Gulf of Izmir, western Anatolia. In this area, the east-west oriented Gediz graben intersects with the NE-SW oriented Bakircay Graben. A velocity-depth model together with pre-stack depth migration allowed two seismic stratigraphic units (SSU1 and SSU2) to be distinguished. These units can be correlated with the stratigraphic succession at the offshore Foca-1 well and correspond to the Upper Miocene to Recent Bozkoy, Ularca and Bayramic Formations with a combined thickness of 1.75 km. The units rest on acoustic basement (SSU3) which has a basin-and-ridge morphology, and which corresponds to the Lower-Middle Miocene Yuntdag Volcanics. A number of lateral velocity variations were identified. In particular, a similar to 90 m wide and similar to 500 m long lenticular-shaped low-velocity zone with an interval velocity of 1.68 km/s was identified in the Quaternary Bayramic Formation. The structure is bounded by negative reflections whose amplitude increases with offset at the top and by strong positive reflections whose amplitude increases with offset at the base, interpreted as possible bright and flat spots respectively. These amplitude events point to the presence of gas-saturated sediments within the study area. The lenticular structure is bounded by strike-slip faults on either side, and by a Miocene - Pliocene unconformity surface below and by shales of the Bayramic Formations above. It is therefore interpreted as a possible structural - stratigraphic trap. The strike-slip faults may allow the migration of hydrocarbons from source rocks located at greater depths. The presence of a low-velocity zone above the lenticular structure reaching up to seafloor may indicate the upward leakage of hydrocarbons from the trap. These observations will contribute to future hydrocarbon exploration activities in the study area.

Data on the long-term persistence of HCV resistance-associated substitutions (RASs) after treatment with direct-acting antivirals (DAAs) are limited. This study evaluated the persistence of NS3, NS5A, and NS5B RASs for up to 5 years after the end of treatment (EOT).We included samples from 678 individuals with an HCV genotype (GT) 1 or 3 infection and virologic DAA treatment failure collected in the European Resistance Database. NS3, NS5A, and NS5B were sequenced, and clinical parameters were evaluated.A total of 242 individuals with HCV GT1a (36%), 237 with GT1b (35%), and 199 (29%) with GT3 and a DAA failure were included. After protease inhibitor failure, the frequencies of NS3 RASs were 40-90% after the EOT. NS3 RASs disappeared rapidly in GT1b and GT3 after follow-up month 3 but were stable (≥60%) in GT1a owing to Q80K. The SOF-resistant NS5B RAS S282T was only found in individuals with GT3a. Non-nucleoside NS5B RASs were frequent in GT1 (56-80%) and decreased to 30% in GT1a but persisted in GT1b. NS5A RASs were very common in all GTs after NS5A inhibitor failure (88-95%), and even after follow-up month 24, their frequency was 65% and higher. However, RASs in GT1b had a stable course, whereas RASs in GT1a and GT3 declined slightly after follow-up month 24 (GT1a, 68%; GT1b, 95%; and GT3, 65%), mainly because of the slow decline of high-level resistant Y93H.We found that low-to medium-level RASs persisted, whereas high-level resistant RASs disappeared over time. Different patterns of RAS persistence according to HCV subtype could have implications for retreatment with first-generation DAAs and for global HCV elimination goals.There are little data on the long-term persistence of HCV resistance-associated substitutions (RASs) after DAA treatment failure, and RASs could have an impact on the efficacy of a rescue treatment. Especially in countries with limited availability of VOX/VEL/SOF or G/P/SOF, different patterns of RAS persistence could have implications for retreatment with first-generation DAAs and for global HCV elimination goals. The different patterns of RAS persistence identified in this study can be used to derive general rules regarding the persistence of RASs after DAA failure that could be applied by physicians in less developed countries to plan individualized HCV retreatment.

Hepatitis C virus infection is causing chronic liver disease, cirrhosis, and hepatocellular carcinoma. By combining direct-acting antivirals (DAAs), high sustained virologic response rates (SVRs) can be achieved. Resistance-associated substitutions (RASs) are commonly observed after DAA failure, and especially nonstructural protein 5A (NS5A) RASs may impact retreatment options.1-3 Data on retreatment of DAA failure patients using first-generation DAAs are limited.4-7 Recently, a second-generation protease- and NS5A-inhibitor plus sofosbuvir (voxilaprevir/velpatasvir/sofosbuvir [VOX/VEL/SOF]) was approved for retreatment after DAA failure.8 However, this and other second-generation regimens are not available in many resource-limited countries or are not reimbursed by regular insurance, and recommendations regarding the selection of retreatment regimens using first-generation DAAs are very important. This study aimed to analyze patients who were re-treated with first-generation DAAs after failure of a DAA combination therapy.

The radiological evaluation of the upper gastrointestinal tract (GI tract) is a diagnostic challenge. Although endoscopy has pushed radiographic methods into the background, these methods continue to play a key role in the diagnosis of dysphagia. In addition, cross-sectional imaging (computed tomography, magnetic resonance imaging) is increasingly used in complex clinical cases to evaluate surrounding tissue changes.By combining conventional double-contrast techniques with a video recording, the entire upper GI tract can be assessed both anatomically and functionally in one examination procedure.In addition to the clarification of swallowing disorders, videofluoroscopy can be used to assess postoperative control after antireflux and bariatric surgery. To obtain optimal results in video swallowing studies, the procedure should be adapted to the individual symptoms of the patient.

Background Rectovaginal fistula is an extremely distressing condition for the patients. There is still no generally accepted standard surgical treatment strategy. Especially the influence of diversion stoma creation on patients' outcome remains controversial. Thus, the aim of this study was to analyze the influences of diversion stoma on the outcome of patients treated because of rectovaginal fistula with special regard to perioperative complications and recurrence rates. Methods Between 2003 and 2013, all patients treated due to rectovaginal fistula in our institutions were retrospectively analyzed. A total of 81 procedures were performed in 62 patients. Procedures were divided into two groups depending on the presence of a diversion stoma or not (diversion stoma, n = 42 vs. no stoma, n = 39). Results The overall rate of fistula recurrence was 44% without statistical significance in-between the study groups (49 vs. 38%; p = 0.603). Diversion stoma had no influence on complication rates, wound infections or number of operative revisions. Patients treated with diversion stoma had significantly higher ASA-scores (2.6 ± 0.6 vs. 2.1 ± 0.8; p = 0.011), higher rates of malignoma (58 vs. 17%; p = 0.001) and larger sizes of fistula (1.67 ± 0.08 vs. 1.51 ± 0.46 mm; p = 0.012). The in-hospital stay was significantly longer in these patients (30 ± 66 vs. 15 ± 15 days; p = 0.023). Conclusions Our data suggest that diversion stoma creation does not influence the outcome of patients with rectovaginal fistula with special regard to rates of fistula recurrence. On the other hand it is mainly used in complex cases of sick patients and larger fistula sizes. Prospective clinical studies need to be conducted to reinforce these findings.

We present THz surface emission by difference frequency generation in nonlinear quantum cascade lasers operating at room temperature. The device comprises two separate, transversely superimposed gratings, one for selective feedback of the mid-infrared modes and one for surface emission of the generated THz radiation. The mid-infrared grating is realized as a higher order, loss-coupled distributed feedback grating for single mode emission at two distinct wavelengths. It defines the spatial distribution of the nonlinear polarization wave, which allows for precise placement of the second order top grating for surface emission.

Background & Aims Little is known about substitutions that mediate resistance of hepatitis C virus (HCV) to direct-acting antivirals (DAAs), due to the small number of patients with treatment failure in approval studies. It is important to identify resistance patterns to select effective salvage treatments. Methods We performed a comprehensive analysis for resistance-associated substitutions (RASs) in HCV genes (nonstructural protein [NS]3, NS5A, NS5B) targeted by DAAs. We compared NS3, NS5A, and NS5B sequences from 626 patients in Europe with DAA failure with sequences from 2322 DAA-naive patients, infected with HCV genotypes 1 to 4. We considered RASs to be relevant if they were associated with DAA failure in patients or conferred a greater than twofold change in susceptibility compared with a reference strain in in vitro replicon assays. Data were collected on pretreatment status, DAA regimen, the treatment initiation date and duration, and virologic response. Patients who received at least 4 weeks of antiviral treatment were included in the analysis. Results RASs in NS3 associated with simeprevir or paritaprevir failure include R155K and D168E/V. In addition, several RASs were specifically associated with failure of simeprevir (Q80K/R in patients with genotype 1a or 4) or paritaprevir (Y56H in combination with D168V in patients with genotype 1b). Y93H in NS5A was the RAS most frequently associated with failure of daclatasvir, ledipasvir, or ombitasvir in patients with genotype 1b infection, and L31M was associated with failure of daclatasvir or ledipasvir, but not ombitasvir. RASs in NS5A were heterogeneous among patients with HCV genotype 1a or genotype 4 infections. In patients with HCV genotype 3, Y93H was associated with resistance to daclatasvir, but no RASs were associated with ledipasvir failure, pointing to a limited efficacy of ledipasvir in patients with genotype 3. Among patients failed by sofosbuvir-containing regimens, L159F was enriched in patients with genotype 1b (together with C316N) or genotype 3 infection, whereas the RAS S282T was rarely observed. Conclusions We compared RASs in NS3, NS5A, and NS5B among patients failed by DAA therapy. Theses varied with the HCV genotype and subtype, and the different drug classes. These findings might be used to select salvage therapies.

Atmospheric Plasma Jet Machining (PJM) is a technology for non-mechanical ultra-precision surface shape generation, shape error correction and smoothing based on atmospheric plasma jets. PJM is favorably applied to generate optical surfaces like aspheres, acylinders, or free-forms but also to improve the surface shape accuracy in a very fast and cost-efficient way. For that purpose a mainly fluorine containing plasma jet is brought into contact with a surface to locally remove material by a chemical reaction forming volatile products. Hence, the technology is limited to materials like silicon, fused silica and similar, or silicon carbide. Furthermore, the etch profile results from a convolution of the radical and the temperature distribution at the surface. Since the temperature distribution is also influenced by the plasma jet this leads to a non-linear dependence of the removal function of the plasma tool on its velocity. Using the dwell-time algorithm for deterministic surface machining by superposition of the local removal function of the plasma tool an advanced process simulation is necessary. In a first local approximation the velocity dependence of the removal function, which has to be determined previously, must be incorporated. Second order thermal effects due to inhomogeneous heating caused by the part geometry and the tool path can be managed by a sophisticated calculation of the surface temperature evolution during machining based on the Finite Element Method (FEM). With the help of this procedure the accuracy and convergence of the machining process can be significantly improved. In the article several examples of surface processing using plasma jet machining are presented. (© 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

We present a novel design for a nonlinear quantum cascade laser emitting THz at room temperature. The device is based on a single active region design, providing both a giant nonlinearity optimized for difference frequency generation and ultra-broad optical gain for two distinct mid-infrared wavelengths.

Das kolorektale Karzinom stellt sowohl in Osterreich wie auch in Deutschland eine grose gesundheitspolitische Herausforderung dar. Da die Teilnahme seitens der Betroffenen an Koloskopievorsorgeprogrammen eher gering ausfallt, wird immer wieder die Frage nach alternativen Untersuchungsmethoden aufgeworfen. Hier scheint die CT-Kolonographie eine schonende Alternative darzustellen, welche eine hohe Patientenakzeptanz aufweist. Die CT-Kolonographie hat sich in den letzten Jahren neben der konventionellen Koloskopie als radiologische Methode zur Untersuchung des gesamten Dickdarms etabliert. Aus axial akquirierten zweidimensionalen Bildern werden dreidimensionale Darstellungen generiert, die einen virtuellen endoskopischen Flug durch das Kolon ermoglichen. Darum ist diese Untersuchung auch unter dem Synonym „virtuelle Koloskopie“ bekannt. Die CT-Kolonographie wurde methodisch in den letzten Jahren kontinuierlich weiterentwickelt. Einerseits hat die stetige Abnahme der Schichtdicke (aktuell ≤ 1 mm) zu verbesserten Volumendatensatzen beigetragen, andererseits gab es einen deutlichen Entwicklungssprung in der Nachverarbeitungssoftware. Zahlreiche Studienergebnisse haben in letzter Zeit gezeigt, dass die Detektionsraten bei histologisch fortgeschrittenen Adenomen mit den Ergebnissen der konventionellen Koloskopie vergleichbar sind. Mittlerweile ist die CT-Kolonographie eine in der taglichen Routine etablierte Untersuchungsmethode sowohl bei symptomatischen als auch asymptomatischen Patienten (Screening). Studiendaten belegen mittlerweile eindeutig, dass die CT-Kolonographie alternativ zur Koloskopie eine leistungsfahige Untersuchungsmethode fur das kolorektale Karzinom darstellt. Um gute Befundergebnisse zu erzielen, sind eine entsprechende Vorbereitung inklusive „fecal tagging“, ein standardisiertes technisches Vorgehen wahrend der Untersuchung und eine Expertise sowohl in der 2-D- wie auch in der 3-D-Befundung wesentliche Voraussetzungen.

Bei geriatrischen Patienten mit akuter korperlicher Erkrankung gibt es eine hohe Komorbiditat von Depression und Demenz. Differenzialdiagnostisch mussen eine Pseudodemenz bei aktueller depressiver Erkrankung, die Depression als Risikofaktor fur die Entwicklung einer Demenz und eine depressive Storung, die haufig im Fruhstadium einer Demenz auftritt, unterschieden werden. Sowohl in der Symptomatik als auch in auslosenden Faktoren gibt es Uberschneidungen und Besonderheiten, die in der AIDE-cog-Studie (Acute Illness and Depression in Elderly cognition trial) mittels eines qualitativen Designs evaluiert wurden. In einem zweiten, prospektiv randomisierten, kontrollierten Teil dieser Studie wurde quantitativ eine Zwischenauswertung der Auswirkung von kognitiver Beeintrachtigung auf den Therapieeffekt einer kognitiven Verhaltenstherapie bei akut korperlich erkrankten geriatrischen Patienten mit komorbider Depression vorgenommen. Hier zeigt sich, dass schon bei einer leichten Demenz deutlich schlechtere Behandlungsergebnisse erzielt werden. Die Evaluation anderer psychotherapeutischer Therapieverfahren, die an noch erhaltenen kognitiven oder emotionalen Funktionen ansetzen, ist anzustreben.

The latest advances in 1550-nm high-speed short-cavity vertical-cavity surface-emitting lasers (VCSELs) are presented. The electrical, optical, and thermal design of these devices is discussed with respect to their high-speed modulation behavior. The implemented design improvements allow high output powers for ambient temperatures up to 90°C, high differential quantum efficiencies up to 40%, temperature-stable single-mode emission, low thermal resistances down to 1.6 K/mW, small-signal modulation bandwidths in excess of 17 GHz, and error-free data transmission at room temperature at data rates of 35 Gb/s in back-to-back configuration and up to 25 Gb/s over 4.2 km of single-mode fiber.

We present a wavelength prediction procedure on the basis of X-ray measurements and simulations for InP-based injectorless quantum cascade laser (QCL) devices. These lasers show excellent performance in the mid-infrared wavelength range, but are very sensitive to growth deviations, which cause strong wavelength shifts and are a serious obstacle for applications like gas sensing. However, by XRD-simulations of the active region, which consists of InAs, AlAs, GaInAs and AlInAs, the thicknesses and compositions can be extracted and are used as input values for bandstructure calculations, so that a prediction for the resonance energy of the laser transition can be obtained. With this technique a wavelength evaluation of injectorless QCLs with 3% accuracy could be accomplished, which is an essential improvement in applications like gas sensing.

An equivalent-circuit model for a novel 1.55- μm buried tunnel junction vertical-cavity surface-emitting laser chip is proposed based on the structure of the device. The values of the equivalent-circuit elements are determined by fitting the reflection and transmission coefficients at different bias currents. Good agreement between measured and simulated results implies the validity of the equivalent-circuit model. The influences of the buried tunnel junction, active region, and parasitic parameters on the high-frequency responses are investigated based on measurements and theoretical predictions. It is shown that the impedance of the device will change with the bias current, even if the bias current is above threshold, which is different from the edge-emitting laser, and the frequency responses depend on both the buried tunnel junction and mesa diameters.

Die eosinophile Osophagitis (EO), ein primar internistisches Krankheitsbild, sollte dem Chirurgen und Endoskopiker als Differenzialdiagnose der Dysphagie gelaufig sein. Wir prasentieren einen chronischen Fall einer EO. Wie so haufig, zeigen sich makroskopische Hinweise auf die ursachliche Erkrankung. Die Diagnose wird letztendlich durch den histologischen Befund einer makroskopisch unauffalligen Mukosa des Osophagus gestellt, welche sich bei 10% der EO findet. Eine Stufenbiopsie ist zur Diagnosesicherung notwendig. Ein kurzer Uberblick uber Therapie und Verlauf sowie ein Review der Literatur werden gegeben.

A novel long-wavelength vertical-cavity surface-emitting laser (VCSEL) structure based on a subwavelength high-contrast grating (HCG) as the output mirror has been realized. By design, these devices are highly polarization stable, are single mode at large apertures, and solve the VCSEL-mirror problem at long wavelengths in an elegant way. With cost-effective mass fabrication in mind, the top HCG reflector consists of amorphous silicon on isolator (amorphous silica). The single-mode laser emission is tailored to be around 1320-nm wavelength, targeting applications in high-speed optical data transmission, particularly those for passive optical networks. We report single-mode emission for devices with apertures as large as 11 $\mu\hbox{m}$ operating in continuous wave with output powers in excess of 0.4 mW. Pulsed operation with output powers up to 4 mW at room temperature is demonstrated as well. This is the first electrically pumped VCSEL structure realized in this wavelength regime utilizing an HCG mirror.

BACKGROUND: The present study examines the causes and surgical management in children who under-went surgery for a mechanical Ileus. PATIENTS: We studied all children up to the age of 18 years who had undergone a surgical inter-vention for a mechanical ileus between 1.1.1996 and 31.12.2006. 89 children were included in this retro-spective study. RESULTS: Of the total of 89 children 15 were -newborn (16.9 %), 23 babies (25.8 %), 19 toddlers (21.3 %) and 32 school children (36 %) at the time of the operation. 51 of the 89 children had undergone at least one previous abdominal operation. Intraoperative findings showed the cause for the ileus to be adhesions in 56 and a bowel invagination in the remaining 11 children. Associated malformations were found in 34 children, the most frequent being malformations of the heart and gastrointestinal tract. The most frequent surgi-cal intervention was adhesiolysis in 56 children (62.9 %), followed by the reposition of invaginat-ed intestine in 11 (12.4 %). Bowel resection was -necessary in 23 children (25.8 %). CONCLUSION: The risk for developing an ileus due to adhesions increases with the number of previous operations. Surgical intervention for an ileus aims to decompress the overstretched bowel and to restore gastrointestinal flow by removing the mechanical obstruction. One third of the children with an ileus have accompanying malformations. Children with a mechanical ileus should undergo surgery as soon as possible.

Growth studies of Ga 1− x In x As 1− y N y quantum wells with indium contents covering the full compositional range ( x In =0…1) have been performed using a gas-source MBE and a valved nitrogen plasma source manufactured by the company ADDON. By using GaAs- and InP- as well as InAs substrates, differently strained GaInAsN-layers were produced, offering a complete overview of the relative bandgap shrinkage with respect to nitrogen-free GaInAs structures, after 1% nitrogen is incorporated. We have shown that this relative bandgap shrinkage depends on the absolute value of indium content of the GaInAs host matrix. As a result a new parameter e was defined describing the relative bandgap shrinkage per percent incorporated nitrogen. When plotting this parameter over the complete range of indium content, a nearly linear decrease occurs.

GaInPSb bulk and superlattice layers have been grown by metal organic vapour phase epitaxy (MOVPE) at low growth temperatures on exact and misorientated InP substrates. Optical and structural studies of the properties of the material reveal that phase separation plays an important role in the growth of this alloy, which is indicated by very broad linewidths in low-temperature photoluminescence (PL) measurements. To explain this behaviour simple miscibility gap calculations for the materials GaInPSb, GaInAsSb and GaInAsP have been performed using the regular solution model. A comparative growth analysis of GaInAsP, GaInPSb bulk and InPSb, GaInAsSb and GaAsSb superlattice structures showed that just the phosphorus- and antimony-containing alloys exhibited the broad low temperature (4 K) PL linewidths (FWHM) of about 50–100 meV. So it can be assumed that due to the large difference in binding energies phosphorus-containing antimonides require much more effort for good crystal quality than equal arsenical alloys.

Aim:To investigate the effect of timolol and latanoprost on the extracellular matrix organisation, inflammatory infiltration, and expression of matrix metalloproteinases (MMPs) and tissue inhibitors of matrix metalloproteinases (TIMPs) in the human conjunctiva.Methods:Conjunctival biopsies were obtained from the inferior fornix during routine cataract surgery from 20 patients with primary open-angle glaucoma, who had received a monotherapy either with timolol or latanoprost, and from 10 non-glaucomatous patients. Specimens were investigated by light microscopy, immunohistochemistry using antibodies against MMP-1,-3, TIMP-2,-3 and CD 68 antibodies and by quantitative transmission electron microscopy.Results:The number of collagen fibres was significantly decreased in latanoprost-treated conjunctival specimens compared with timolol-treated eyes (p<0.01) but showed no difference to controls. Amorphous material was increased in both treated groups compared with controls (pConclusions:Latanoprost-treated conjunctival specimens showed a decreased stromal collagen density and a less pronounced inflammatory infiltration. The upregulation of MMP-1 and MMP-3 in latanoprost-treated eyes might explain the reduced extracellular matrix accumulation in the conjunctival stroma. Therefore, latanoprost therapy might have a more favourable effect on the outcome of glaucoma filtering surgery.

Despite the progress concerning operative techniques, parastomal hernias remain a surgical challenge. The high risk for recurrence demands precise indications for operative repair. Mesh implants reduce the recurrence rate. Among such procedures, the retromuscular mesh augmentation represents an established method, whereas the value of other techniques still has to be defined. Also, the prophylactic use of meshes is able to reduce the incidence of parastomal hernias. With regard to short- and long-term complications, their general recommendation must be proven in further studies.

Thin-section multidetector-row computed tomographic (MDCT) colonography is a powerful tool for detection and classification of colonic lesions. It is based on a helical thin-section (0.75-2 mm) CT dataset of the cleansed and air-distended colon. 2D and 3D projections are prepared and used for image interpretation. Evaluation of CT colonography datasets requires correct perception and interpretation of colonic lesions and filling defects. Various criteria are needed for correct interpretation of filling defects and differentiation between genuine lesions and artifacts. Such defects are characterized by their morphology, their structure, the absorption of contrast medium and their mobility. Knowledge of the morphologic and attenuation characteristics of common colonic lesions and of artifacts is essential for the correct interpretation of a filling defect. This review article summarizes the main imaging features of polyps, diverticula, lipomas, and carcinomas and also of common pseudolesions of the colon.

A fiber-based remote measurement setup for tunable diode laser absorption spectroscopy, introducing an electrically pumped, micromechanical vertical-cavity surface-emitting laser with single-mode emission spectrum, narrow linewidth of 40 MHz, and broadband, continuous wavelength coverage of 51 nm around 1.55 mum is presented. The tunable laser spectrometer is employed for analysis of heterogeneous gas compositions and simultaneous detection of two species, ammonia and carbon monoxide, in a single continuous wavelength sweep. Broadband absorbance spectra are captured at elevated temperatures up to 300 degC revealing opposed temperature dependencies for selected transitions.

Ziel der Studie ist es, Augeninnendruckschwankungen bei Glaukompatienten und Normalprobanden im Tages- und Nachtverlauf zu ermitteln; wobei jeweils Messungen in der sitzenden und liegenden Position erfolgen. In einer prospektiven klinischen Studie wurde bei 30 Patienten mit bekanntem primar chronischem Offenwinkelglaukom und 50 Normalprobanden der Augeninnendruck alle 4 h beginnend um 8 Uhr uber einen Zeitraum von 24 h gemessen. Zusatzlich wurden die systemischen Parameter Herzfrequenz und Blutdruck bestimmt. Um 12 Uhr wurde zunachst eine Messung am sitzenden Patienten durchgefuhrt mit anschliesender Liegenddruckmessung nach 20-minutigem Liegen. Um 24 Uhr erfolgten die Messungen in umgekehrter Reihenfolge. Um 4 Uhr wurde nur im Liegen gemessen, die Messungen zu allen ubrigen Zeitpunkten erfolgten im Sitzen. Die Sitzendmessungen wurden mittels Goldmann- und Perkins-Tonometrie, die Liegendmessungen mittels Perkins-Tonometrie durchgefuhrt. Der mittels Perkins-Tonometrie bestimmte Augeninnendruck lag in beiden Gruppen 0,9 mmHg unter den mittels Goldmann-Tonometrie bestimmten Werten. Im Liegen zeigten sich insgesamt hohere Werte als im Sitzen: Um 12 Uhr betrug die Differenz 1,8±2,7 mmHg (p=0,001) bei den Normalprobanden und 1,3±2,7 mmHg (p=0,013) bei den Glaukompatienten. Um 24 Uhr in der Liegendmessung war dieser Unterschied noch deutlicher mit 2,4±3,4 mmHg bei den Normalprobanden und 5,6±3,2 mmHg bei den Patienten mit primar chronischem Offenwinkelglaukom (p=0,001). Der Blutdruck wies in beiden Gruppen die niedrigsten Werte in den nachtlichen Messungen um 24 und 4 Uhr auf. Bei Augeninnendruckmessungen in der sitzenden Position zeigte sich kein statistisch signifikanter Unterschied zwischen den Glaukompatienten und den Normalprobanden. In der Liegendmessung war der Augeninnendruck jedoch signifikant hoher als im Sitzen, was sich besonders bei den Glaukompatienten zeigte. Diese Beobachtung konnte durch eine mangelhafte Regulation des „fluid shifts“ bei Patienten mit primar chronischem Offenwinkelglaukom erklart werden, welche zu einer weiteren Progression des glaukomatosen Schadens beitragen kann.

Hintergrund Ziel unserer Studie war der Vergleich zweier Ultraschallpachymeter anhand der gemessenen zentralen Hornhautdicke (CCT).

We present a micromechanically tunable long-wavelength vertical-cavity surface-emitting laser with a buried tunnel junction aperture and a stable half-symmetric cavity for full mode control. The conjunction of the active part 'half-VCSEL' and the curved MEMS-mirror in a two-chip assembly enables high output power singlemode emission exceeding 1?mW. Electrothermal actuation of the micromechanical chip allows us to extend the single wavelength performance to a continuously tunable, selectively wavelength-addressable spectrum of 28?nm. The concave curvature and the resulting long air-gap cavity are designed to favour the resonance of the fundamental mode, i.e. to match the phase front predicted by Gaussian beam theory corresponding to the aperture diameter of 10??m. The spatial beam profile of the MEMS-VCSEL is measured in the far-field and compared with a conventional VCSEL with a fixed plane top mirror. The polarization is controlled by a dominating mirror asymmetry. High sidemode suppression over the whole tuning range with respect to both the transverse modes (>40?dB) and the polarization modes (>30?dB) is demonstrated.

Hintergrund Ziel der Studie war es, den Durchmesser von zirkularen OCT-Scans um die Papille zu bestimmen, bei dem am besten zwischen Glaukom und Gesunden unterschieden werden kann.

BACKGROUND: Until now it was thought that morphological parameters of the eye such as corneal thickness, corneal curvature and axial length do not affect tonometry results. However, the aim of this study was to find out whether there actually is an influence of these parameters on applanation tonometry. PATIENTS AND METHOD: In this prospective study we examined 125 eyes of 125 normal patients with a corneal thickness of 568.8 +/- 43.79 microm, a corneal curvature of 7.72 +/- 0.27 mm and an axial length of 23.62 +/- 2.05 mm. Before performing a phacoemulsification, the anterior chamber was temporarily punctured. With a closed system the intraocular pressure (IOP) was manometrically set at 20, 35 and 50 mmHg using an H (2)O column. The IOP was then measured with a Perkins tonometer. With these patients we compared 102 eyes that had undergone LASIK due to a myopia of 6.3 +/- 2.17 D. Before and 6 months after surgery, IOD, k-values and central corneal thickness of these patients were measured. RESULTS: At all set pressure levels there was a highly significant correlation of measured IOP and corneal thickness. At all set pressure levels the measured IOP significantly depended on corneal thickness (r(2) = 0.78 - 0.83). After LASIK, IOP was reduced from 16.5 +/- 2.1 to 12.9 +/- 1.9 mmHg. There was a significant correlation between IOP and corneal curvature as well as corneal thickness (r(2) = 0.631; P < 0.001). The biomechanical characteristics of the cornea are changed so that the measured IOP has to be corrected by an additional 0.75 mmHg. CONCLUSION: Since corneal thickness does affect Goldmann applanation tonometry we recommend to use the "Dresden Correction Table" (Tab. ) to achieve the real IOP. Pressure measurements after LASIK are inaccurate because of a change in corneal biomechanics, corneal thickness and curvature and they should be corrected as follows: IOP (real) = IOP (measured) + (540 - CCT)/71 + (43 - K-value)/2.7 + 0.75 mmHg.

Der Augeninnendruck ist nach wie vor der wichtigste Risikofaktor fur die Entstehung eines glaukomatosen Schadens. Neuere Studien weisen darauf hin, dass auch die Hornhautdicke ein Risikofaktor fur die Entstehung einer glaukomatosen Schadigung darstellt. Eine mogliche Ursache hierfur konnte sein, dass die Hornhautdicke die Messung des Augeninnendruckes beeinflusst. Es konnte gezeigt werden, dass bei der Applanationstonometrie nach Goldmann die Messwerte mit der Hornhautdicke korrelieren. Dicke Hornhaute fuhren zu einer falsch hohen Messung des Augeninnendruckes und dunne zu einer falsch niedrigen. Ob es sich bei der Hornhautdicke als Risikofaktor fur das Glaukom um einen reinen Messfehler oder einen Ausdruck biomechanischer Besonderheiten der Glaukomaugen handelt, ist nicht mit Sicherheit geklart. Ein groser Teil des Hornhauteffektes beruht sicherlich auf dem Messfehler bei der Augeninnendruckmessung. Durch die Nichtberucksichtigung der Hornhautdicke konnen Messfehler entstehen, die zu Fehldiagnose und fehlerhafter Behandlung fuhren konnen. Aus diesem Grund sollte die Messung der Hornhautdicke bei Patienten mit einem Glaukom oder Glaukomverdacht nicht fehlen.

This paper presents a hygrometer setup for measuring the concentration of water vapor in air by means of infrared absorption spectroscopy. Recently developed vertical-cavity surface-emitting lasers (VCSELs) emitting near 1.84 /spl mu/m are used as source of the infrared light. The laser hygrometer is able to calculate the density of water molecules from the measurement of one single light-current characteristic, without any additional reference measurement. The absolute and relative humidity are calculated from the water molecule density and the temperature of the ambient air.