Broadband antireflection coatings with low polarization splitting.

A major problem for optical systems is the polarization splitting occurring at any interface in the event of oblique light. Low-index nanostructured silica layers were produced by overcoating an initial organic structure with silica and subsequent removal of the organic constituents. The nanostructured layers can be tailored to achieve defined low effective refractive indices down to 1.05. They can also be stacked together with homogeneous layers to produce broadband antireflective coatings with very low polarization splitting. Especially thin interlayers that separate the low-index structured layers turned out to be useful to optimize the polarization properties.

Combined antifogging and antireflective double nanostructured coatings for LiDAR applications.

To increase the performance of optical systems, a good antireflective coating is required to ensure low reflectance and high transmittance of optical surfaces. Further problems, such as fogging that causes light scattering, negatively affect the image quality. This implies that other functional properties are also required. Presented here is a highly promising combination of an antireflective double nanostructure on top of an antifog coating with long-term stable properties, generated in a commercial plasma-ion-assisted coating chamber. It is demonstrated that the nanostructures do not affect the antifog properties and can be successfully used for many applications.

Coating-relevant properties of high-index optical polymers for automotive applications.

High-transparent polymers exhibiting a refractive index beyond 1.6 enhance the available range of optical plastics. The aim of this study is to evaluate optical polyesters (OKP-1 and OKP-4) and special new polycarbonates (PCs) (EP-6000 and EP-8000) in comparison with the widely used poly-bisphenol-A-based PC. The work is focused on optical properties as well as other properties that are important for the deposition of optical coatings. Plasma ion-assisted deposition is used for the deposition of an abrasion resistant antireflective coating (AR-hard).

Ultraviolet-transparent low-index layers for antireflective coatings.

Nanostructured low-index layers are useful as the last layers of antireflective (AR) coatings because they can broaden their spectral ranges and improve the performance for oblique light incidence. Structuring of evaporated organic layers by plasma opens a route to produce inorganic interference stacks and low-index layers in the same vacuum process. The organic material uracil has been investigated as a template material for AR nanostructures. An additional plasma-treatment step was added to the manufacturing process, which decreases the organic fraction of the coating substantially. As a result, a better environmental stability and higher transmission in the ultraviolet range was achieved.

Investigations on synthesis and structure elucidation of novel [1,2,4]triazolo[1,2-a]pyridazine-1-thiones and their inhibitory activity against inducible nitric oxide synthase.

The inducible nitric oxide synthase (iNOS) is a target of great research interest due to its importance in a number of diseases, for example, septic shock and inflammatory lung diseases. A variety of 3-substituted [1,2,4]triazolo[1,2-a]pyridazine derivatives was synthesized by ring closure with hexahydropyridazine-1-carbothioamide by using aliphatic and aromatic aldehydes. The activity of the new substances was tested on the insulin-secreting rat insulinoma cell line RINm5F. iNOS was expressed through exposure to interleukin-1ß (IL-1ß) and interferon-γ (IFN-γ). A number of the investigated compounds were more active than the reference inhibitor aminoguanidine (AG). Structure-activity relationships showed that a phenyl substituent in position 3 is apparently essential for inhibition.

Evaluation and development of a predictive model for ultrasound-guided investigation of neck metastases.

Ultrasound investigations for the correct identification of lymph node metastases depend on the experience and qualifications of the investigator; thus, model that provides better preoperative evaluation is desired. Data from 290 patients with an upcoming neck dissection were analyzed to compare the preoperative ultrasound assessment of neck metastases with the pathologically proven postoperative neck status. In total, 364 data sets with 200 malignant and 164 benign lymph nodes were explored. The minimal and maximal transverse diameters and their ratio were shown to be especially good parameters for sensitivity, whereas the echostructure and the presence of a hilum were good for specificity. A model incorporating the evaluated markers is presented. The model provides better judgement of neck lymph nodes in a more objective manner. Using logistic regression, five parameters were identified to predict metastases.

Evaluation of diagnostic criteria in grey parrots (Psittacus erithacus) with suspected atherosclerosis.

OBJECTIVE: Atherosclerosis is a common disease in older psittacines living in captivity with inadequate housing conditions. However, diagnosis in the living bird remains difficult and the disease is often only recognized during post mortem examination. In this context, we aimed at investigating the diagnostic value of currently reported methods in African grey parrots (Psittacus erithacus). MATERIAL AND METHODS: 7 clinically healthy African grey parrots and 32 African grey parrots with suspected atherosclerosis were evaluated in this study. An overall scoring system was implemented based on clinical signs, measurement of blood cholesterol and triglyceride levels, a radiographic exam, and an echocardiogram in B-mode. Furthermore, measurements of the blood flow velocity in the aortic root, heart rate and velocity time integral were performed using the spectral Doppler ultrasonographic function. RESULTS: Measurements of the blood flow velocity in the aortic root showed highly significant differences between the clinically healthy group and a subset of the patient group. Significant differences between the groups also were evident concerning the results of the overall scoring and of the initial examinations. CONCLUSION: The results support that combining spectral Doppler ultrasonographic examination with other diagnostic options may be used to substantiate suspected atherosclerosis and provide additional information regarding the cardiovascular status of the patient. CLINICAL RELEVANCE: The presented findings indicate that employing the described diagnostic methods allows for an intra vitam diagnosis of atherosclerosis and therefore an earlier initiation of treatment.

Improved scratch resistance for antireflective coatings on sapphire.

Antireflective coatings on sapphire were optimized by variation of the coating design, the total thickness, and the highly refractive material used. The coatings were characterized with a focus on their scratch resistance. An increased resistance against scratching wear is shown for hafnia-containing coatings with a total thickness of about 500 nm.

Plasma-etched organic layers for antireflection purposes.

Organic layers can be used to realize special functions in optical interference coatings. Suitable compounds for such layers were thermally evaporated and characterized. A plasma etching procedure was applied to produce nanostructures on top of the organic layers to reduce their effective refractive indices. Broadband antireflective coatings were obtained by combining these artificial low-index layers with conventionally prepared interference stacks.

Wide-Angle Broadband Antireflection Coatings Prepared by Atomic Layer Deposition.

A novel broadband antireflective coating with ultra-low residual reflectance for light incidence angles from 0° up to 60° is presented. The system consists of an interference multilayer coating made by atomic layer deposition (ALD) combined with a low- n nanoporous SiO2 top-layer obtained by wet-chemical etching of an atomically mixed SiO2/Al2O3 ALD composite. The average residual reflectance measured at normal incidence for double-sided coated B270 glass substrates is only 0.5% in a broad spectral range from 400 to 1100 nm. The average reflectance of the substrate considering both front and rear sides decreased in the visible spectral range of 420-680 nm from 9.9 and 15.8 to 0.4 and 1.8% at an oblique angle of incidence (AOI) of 45° and 60°, respectively, by applying the hybrid ALD antireflection coatings. The measured average transmittance reaches 99.5% at AOI 6° in the 400-950 nm spectral range. Measurements three weeks after preparation show only a small reduction of the average transmittance to 99.3% in this spectral range spanning 550 nm. Ten months later, the average transmittance is still 99.0%, whereby the sample handling might have also affected the performance. The hybrid ALD system shows excellent conformal AR performance on a strongly curved B270 aspheric lens with a diameter of 50 mm and a height of 25 mm. The presented process is a promising route toward omnidirectional AR coatings on complex 3D optics, which are increasingly important for consumer and high-performance optical systems.

Sexual behaviour as the limiting and linking factor in HIV-infected people in rural Zimbabwe.

Although the incidence of AIDS continues to increase in Zimbabwe, no systematic investigation has been done of the contextual (behavioural and situational) variables important to the tailoring of AIDS educational prevention programmes for those at risk. As part of a World Health Organization-recommended cotrimoxazole prophylaxis programme to 1146 HIV-positive individuals in rural Zimbabwe, data were collected on risk behaviours and characteristics of all participants. Outcomes included condom use, relationship, marital status, duration of the programme and reason for HIV testing. Forty-five participants (4.1%) reported always using condoms, 379 (34.5%) reported occasional use and 673 (61.4%) reported no condom use. Statistical analysis showed significant positive correlations between condom use and participant age, duration of the programme, the reason for HIV testing, knowledge about the partners' HIV status and the partner's awareness of the patient's HIV-positive status. Results reflect the need to target subpopulations, for specific HIV/AIDS education initiatives in rural Africa.

Agonists of peroxisome proliferator-activated receptor gamma inhibit cell growth in malignant melanoma.

Peroxisome proliferator-activated receptor gamma is a member of the nuclear receptor superfamily involved in adipocyte differentiation and glucose homeostasis. There is evidence that peroxisome proliferator-activated receptor gamma may also act as a tumor suppressor. Here, we demonstrate expression of peroxisome proliferator-activated receptor gamma in benign melanocytic naevi, different variants of primary cutaneous melanomas, and melanoma metastases. Peroxisome proliferator-activated receptor gamma protein and peroxisome proliferator-activated receptor gamma1 mRNA were also detected in human melanoma cell lines. The peroxisome proliferator-activated receptor gamma specific agonists 15-deoxy-Delta12,14-prostaglandin J2, troglitazone, and rosiglitazone dose-dependently inhibited cell proliferation in four melanoma cell lines, whereas a specific agonist of peroxisome proliferator-activated receptor alpha had no such effect. At a concentration of 50 microM rosiglitazone, the most potent peroxisome proliferator-activated receptor gamma agonist tested suppressed cell growth by approximately 90%. Apoptosis could be induced in melanoma cell lines by incubation with tumor-necrosis-factor-related apoptosis-inducing ligand. In contrast, the growth inhibitory effect of peroxisome proliferator-activated receptor gamma activation was independent of apoptosis and seemed to occur primarily through induction of cell cycle arrest. Our data indicate that melanoma cell growth may be modulated through peroxisome proliferator-activated receptor gamma.

Characterization of lymphoid follicles with red ring signs as first manifestation of early Crohn's disease by conventional histopathology and confocal laser endomicroscopy.

BACKGROUND AND AIMS: Clinical observations suggest that the lymphoid follicles (LFs) may play a crucial role in the pathogenesis of inflammatory bowel disease (IBD), especially in Crohn's disease (CD) as the site of initial mucosal inflammation. The aim of this study was to compare the morphology of LFs in CD, ulcerative colitis (UC) and control patients using confocal laser endomicroscopy (CLE) in correlation to histological and immunohistochemical findings of biopsies. METHODS: 79 patients with IBD (46 with CD, 32 with UC and 1 patient with indeterminate colitis) and 67 controls patients were enrolled prospectively in this study. Median age was 32.5 years (range 19-65) and 37.4 years (range 20-65 years) respectively. To analyze the LFs, standardized images from the terminal ileum and the colon were taken using white-light video endoscopes. Additionally, CLE was performed to analyze subsurface structure of LFs. Targeted biopsies of LFs were analyzed using haematoxylin and eosin stain and immunohistochemistry. RESULTS: LFs were seen in all parts of the lower GI tract, but mostly in the terminal ileum and cecum. Endoscopy in 15 out of 17 patients with the first manifestation of CD showed LFs surrounded by red ring (so-called red ring sign, RRS). Histologically, LFs with RRS showed hypervascularization at the base of the LFs associated with numerous CD15-positive granulocytes. Similar features were not seen in LFs without RRS and in the control group. In some LFs with RRS early aphthous ulcers were seen. Using CLE, RRS showed abolished normal crypt architecture, crypt distortion, increased cellular infiltrate within the lamina propria, and dilated vessels. CONCLUSION: LFs with RRS probably represent an early sign of aphthous ulcers in early CD and, thus, may be considered as early markers of first manifestation and flares in CD.

Stochastic subwavelength structures on poly(methyl methacrylate) surfaces for antireflection generated by plasma treatment.

Subwavelength structures of sufficient height-to-width aspect ratio are adequate for reduction of the Fresnel reflection of surfaces. In the case of low-pressure plasma-treated polymers, the self-organized features are stochastically distributed on the surface area with unequal shapes. Common descriptions use effective medium theory along with a continuously altering volume filling factor that together lead to a lateral homogeneous layer with a depth-dependent refractive index. We use a fixed gradient function for the refractive index for reverse engineering of in situ measured broadband optical data, and we compare the results with nonoptic methods.

Low temperature deposition of indium tin oxide films by plasma ion-assisted evaporation.

Coatings of transparent conductive oxides, especially indium tin oxide (ITO), are important in different fields. So far, application of these materials has been limited to substrates with high thermal stability. We describe an improved coating process for ITO based on plasma ion-assisted evaporation at a substrate temperature below 100 degrees C, which is suitable for organic substrates. In characterizing the thin films, we used the classical Drude theory to calculate the resistivity from optical film properties and compared the data with linear four-point measurements. X-ray diffraction spectroscopy was used to determine the structural properties of the thin films.

Antireflection coating with UV-protective properties for polycarbonate.

Polycarbonate is the chosen material for covers of automotive displays because it combines high transparency with high breaking strength. The requirements for coatings include an improvement of the scratch resistance and antireflection properties as well as high stability for challenging environmental conditions. A coating that involves all required properties has been developed and deposited onto polycarbonate by plasma-ion assisted deposition.

Molecular interactions in poly(ethylene glycol)-water mixtures at various temperatures: density and isentropic compressibility study.

The densities and sound velocities of mixtures of water with poly(ethylene glycol), poly(ethylene glycol) monomethylether, and poly(ethylene glycol) dimethylether with mean molar weights between 250 and 500 have been measured as a function of mixture composition and temperature between 10 and 40 degrees C. Isentropic compressibilities are derived from the data and are compared to those for the ethylene glycol/water system and for other organic solvent/water mixtures. Relative minima in the mixture volume to ideal volume ratio and in the dependence of the compressibility upon mixture composition are discussed in terms of the conformational variability of the chainlike oligomers, of hydrogen-bonded networks, and of water clusters between the oligomer chains.

Impact of preoperative physiological risk profile on postoperative morbidity and mortality after emergency operation of complicated peptic ulcer disease.

AIM: The aim of this study was to evaluate the preoperative physiological risk profile for postoperative morbidity and mortality after emergency treatment of complicated peptic ulcer disease (PUD). METHODS: Operative notes and hospital files of 261 patients--111 female, 150 male; median age 67 years (range 17-100 years)--undergoing an emergency operation from 1993 to 2005 were analyzed retrospectively. The physiologic subscore of the POSSUM score (POSSUM-phys) was analyzed with regard to predicting postoperative complications. Follow-up was obtained from questionnaires sent to family practitioners or by patient interviews. RESULTS: The overall complication rate was 44%, and mortality was 24%. Among risk factors studied (e.g., sex, patient's age, duration of symptoms, type of surgery), a high POSSUM-phys score was the strongest predictor for postoperative sepsis, anastomotic/suture dehiscence, postoperative bleeding, and mortality. Cut points for patients at risk could be calculated. Surgical procedures (organ-preserving versus resection) had no influence when matched for POSSUM-phys score. Nevertheless, organ resections were associated with higher scores. Recurrent PUD was a rare event (7.6%). CONCLUSION: The preoperative physiologic POSSUM score is a promising instrument for identifying patients at increased risk to develop major postoperative complications after emergency surgery for complicated PUD. Prospective studies are needed to prove its applicability for adjusting treatment to individual patients.

Review of modern techniques to generate antireflective properties on thermoplastic polymers.

Modern optical applications need solutions for providing polymer surfaces with antireflective properties. The problems involved in coating comprise thermal limitations, incompatible mechanical properties of coating and substrate materials, and interaction between polymers and plasma. As an alternative for coating, antireflective properties on polymers can also be obtained by hot embossing or by ion etching of surface structures. My objective is to provide the criteria for choosing suitable deposition or structuring methods based on an understanding of plasma-, radiation-, and ion-induced surface phenomena; material compatibility; mechanical and environmental performance; and cost issues. The potential to produce antireflective interference coatings is documented for plasma-enhanced physical- and chemical-vapor-deposition methods, including modern hybrid techniques, as well as for solgel wet-chemical processes. The review about state-of-the-art coatings focuses on the thermoplastic acrylic, polycarbonate, and cycloolefin polymers.

Antireflection coating design for plastic optics.

The coating of plastics for optical applications is intended to improve the mechanical durability of soft polymers and to serve an antireflection function. Usually a classic four-layer antireflection system is added on top of a single-layer hard coating. With needle optimization, an alternative coating design has been developed. The design is characterized by thin high-refractive-index layers that are almost evenly distributed over the whole stack. Plasma ion-assisted deposition was used to deposit coatings upon poly(methyl methacrylate), polycarbonate, and cyclo-olefin copolymer. Uniform antireflection and high scratch resistance have been achieved.