TOPAS-imaging: extensions to the TOPAS simulation toolkit for medical imaging systems.

Objective. The TOol for PArticle Simulation (TOPAS) is a Geant4-based Monte Carlo software application that has been used for both research and clinical studies in medical physics. So far, most users of TOPAS have focused on radiotherapy-related studies, such as modeling radiation therapy delivery systems or patient dose calculation. Here, we present the first set of TOPAS extensions to make it easier for TOPAS users to model medical imaging systems.Approach. We used the extension system of TOPAS to implement pre-built, user-configurable geometry components such as detectors (e.g. flat-panel and multi-planar detectors) for various imaging modalities and pre-built, user-configurable scorers for medical imaging systems (e.g. digitizer chain).Main results. We developed a flexible set of extensions that can be adapted to solve research questions for a variety of imaging modalities. We then utilized these extensions to model specific examples of cone-beam CT (CBCT), positron emission tomography (PET), and prompt gamma (PG) systems. The first of these new geometry components, the FlatImager, was used to model example CBCT and PG systems. Detected signals were accumulated in each detector pixel to obtain the intensity of x-rays penetrating objects or prompt gammas from proton-nuclear interaction. The second of these new geometry components, the RingImager, was used to model an example PET system. Positron-electron annihilation signals were recorded in crystals of the RingImager and coincidences were detected. The simulated data were processed using corresponding post-processing algorithms for each modality and obtained results in good agreement with the expected true signals or experimental measurement.Significance. The newly developed extension is a first step to making it easier for TOPAS users to build and simulate medical imaging systems. Together with existing TOPAS tools, this extension can help integrate medical imaging systems with radiotherapy simulations for image-guided radiotherapy.

Response of Polypropylene Composites Reinforced with Natural Fibers: Impact Strength and Water-Uptake Behaviors.

Composites from polypropylene (PP) reinforced with hemp strands (HS) are prepared in the current work with the aim of deepening on the influence of this reinforcement on the impact performance of these specific composites. Despite all the research conducted in this field, the effect of this natural reinforcement on the absorbed energy during crack formation and propagation is not fully tackled in previous research works. From the methodology and samples' geometry, the results concluded that the quality of the interface has a noticeable role in the impact resistance of these materials. The interface strength, fiber dispersion and fiber pullout are the main contributors to crack formation, whereas fiber pullout is the main one responsible for crack propagation. Maximum values of absorbed energy were found for PP composites comprising 20-30 wt% of HS and 8 wt% of the coupling agent for the un-notched samples, whereas maximum absorbed energy values corresponded to PP composites with 40 wt% of HS and 4 wt% of coupling agent for the notched samples. The water-absorption behavior in different humid environments is also examined. From the kinetic study, the water diffusion followed a Fickean behavior showing low-diffusion coefficients, increasing with fiber content. This systematic investigation represents a contribution to the analysis of the potential of reinforcing conventional polymers with natural materials, as a strategy towards more sustainable development.

Behavior of the Flexural Strength of Hemp/Polypropylene Composites: Evaluation of the Intrinsic Flexural Strength of Untreated Hemp Strands.

The growing demand for plant fiber-reinforced composites offers new opportunities to compete against glass fiber (GF)-reinforced composites, but their performance must be assessed, revised, and improved as much as possible. This work reports on the production and the flexural strength of composites from polypropylene (PP) and hemp strands (20-50 wt.%), using maleic anhydride-grafted PP (MAPP) as a compatibilizer. A computational assessment of the reaction between cellulose and MAPP suggested the formation of only one ester bond per maleic anhydride unit as the most stable product. We determined the most favorable MAPP dosage to be 0.06 g per gram of fiber. The maximum enhancement in flexural strength that was attained with this proportion of MAPP was 148%, corresponding to the maximum fiber load. The modified rule of mixtures and the assumption of similar coupling factors for tensile and flexural strength allowed us to estimate the intrinsic flexural strength of hemp strands as 953 ± 116 MPa. While falling short of the values for sized GF (2415 MPa), the reinforcement efficiency parameter of the natural fibers (0.209) was found to be higher than that of GF (0.045).

Rapid analysis of strigolactone receptor activity in a Nicotiana benthamiana dwarf14 mutant.

DWARF14 (D14) is an ɑ/ß-hydrolase and receptor for the plant hormone strigolactone (SL) in angiosperms. Upon SL perception, D14 works with MORE AXILLARY GROWTH2 (MAX2) to trigger polyubiquitination and degradation of DWARF53(D53)-type proteins in the SUPPRESSOR OF MAX2 1-LIKE (SMXL) family. We used CRISPR-Cas9 to generate knockout alleles of the two homoeologous D14 genes in the Nicotiana benthamiana genome. The Nbd14a,b double mutant had several phenotypes that are consistent with the loss of SL perception in other plants, including increased axillary bud outgrowth, reduced height, shortened petioles, and smaller leaves. A ratiometric fluorescent reporter system was used to monitor degradation of SMXL7 from Arabidopsis thaliana (AtSMXL7) after transient expression in N. benthamiana and treatment with the strigolactone analog GR24. AtSMXL7 was degraded after treatment with GR245DS, which has the stereochemical configuration of natural SLs, as well as its enantiomer GR24 ent-5DS. In Nbd14a,b leaves, AtSMXL7 abundance was unaffected by rac-GR24 or either GR24 stereoisomer. Transient coexpression of AtD14 with the AtSMXL7 reporter in Nbd14a,b restored the degradation response to rac-GR24, but required an active catalytic triad. We used this platform to evaluate the ability of several AtD14 mutants that had not been characterized in plants to target AtSMXL7 for degradation.

Non-dipper effect in hypertense patients after renal transplantation by 24-hour ambulatory blood pressure monitoring.

OBJECTIVE: Determinate instant and after 1-month non-dipper effect in hypertense patients after renal transplant by 24-hour ambulatory blood pressure monitoring in Hospital General de Zona No. 50, San Luis Potosí, Mexico. METHOD: Descriptive, longitudinal and prospective cohort study of a non-probability convenience sampling in post-transplant patients with hypertension. We collected data from MAPA and includes age, sex, cardiovascular risk factors in variables. Use of central tendency and dispersion measures for descriptive analysis and t Student for inferential analysis. RESULTS: 19 patients were included, 11 male (57.9%) and 8 females (42.1%), with age range 20 to 49 years (median of 30.2 years ± 7.7). Where the non-dipper effect in the first take was 89.5% and in the second take 84.2%. CONCLUSIONS: There is a high frequency of the non-dipper pattern in patients at one month of kidney transplant, the persistence of this hypertension may be, among others, by the use of immunosuppressants. A new category for non-dipper classification is described.

OBJETIVO: Determinar el efecto non-dipper inmediato y posterior a 1 mes en pacientes adultos hipertensos postrasplante renal con monitoreo continuo de la presión arterial de 24 horas, en el Hospital General de Zona No. 50 de San Luis Potosí, México. MÉTODO: Estudio de tipo cohorte, longitudinal, prospectivo, con muestreo no probabilístico por conveniencia de casos consecutivos en pacientes receptores de trasplante renal con hipertensión arterial. Se recogieron los siguientes datos: edad, sexo, factores de riesgo cardiovascular, uso de antihipertensivos o inmunosupresores, y monitoreo ambulatorio de la presión arterial de 24 horas. Se aplicaron medidas de tendencia central y de dispersión para análisis descriptivo, y prueba t de Student para análisis inferencial. RESULTADOS: Se incluyeron 11 hombres (57.9%) y 8 mujeres (42.1%), con una edad de 20 a 49 años (media 30.2 ± 7.7), en los que el efecto non-dipper inmediato fue del 89.5% y posterior a 1 mes fue del 84.2%. CONCLUSIONES: Existe una alta frecuencia del patrón non-dipper en pacientes a 1 mes del trasplante renal. La persistencia de la hipertensión puede ser, entre otras causas, por el uso de inmunosupresores. Se describe una nueva categoría para la clasificación non-dipper.

Value-Creating Strategies in Dairy Farm Entrepreneurship: A Case Study in Northern Spain.

This paper explores different value-creating strategies (VCS) used by dairy farmers engaged in on-farm diversification ventures. In order to explicitly identify the informal strategies followed by 49 farmers in their value-added ventures, we applied a theoretically informed business model framework combining three dimensions: value proposition linked to local food, customer engagement via quality schemes and shorter supply chains, and the key capabilities of the entrepreneur. Using cluster analysis, four different types of VCS were identified and labelled as 'Ecological', 'Single-product', 'Innovative', and 'Traditional'. Whilst we found that these strategies are influenced by contextual factors and the owner's entrepreneurial skills, in general, we did not observe significant differences in performance between them. The results suggest that farmers respond entrepreneurially to sectorial changes adopting those VCS that tend to align with their entrepreneurial capabilities and context, thus enabling them to succeed with any of the strategies pursued. Hence, our work contributes towards clarifying the relationship between VCS, entrepreneurial capabilities, and context. This is important for farmers and policymakers because it reveals the diversity of farm management and the resilience of farm systems. As a result, the potential challenges for Single-product VCS and Traditional VCS are discussed.

Somatic cell counts, reproduction indicators, and technical efficiency in milk production: A stochastic frontier analysis for Spanish dairy farms.

Health and reproductive conditions affect milk yields in dairy cows and may lead to differences in technical efficiency across farms. To investigate this, we created a novel panel data set of 197 dairy farms in northern Spain observed over the period 2006-2014 by combining information from 2 different sources and including data on production variables, somatic cell count, and reproduction indicators, as well as a genetic index. We used these data to estimate a stochastic production frontier where the somatic cell count, age at first calving, and calving interval are included as determinants of technical efficiency. Higher somatic cell count, greater age at first calving, and longer calving intervals were found to decrease technical efficiency, translating into significant losses in profits which we quantify through a simulation exercise. We also quantified the effect of genetic selection on profits, taking into account not only its direct effect on productivity but also its indirect effect through reduced technical efficiency due to the effect of genetic selection on the health and reproduction variables.

Determination of Mean Intrinsic Flexural Strength and Coupling Factor of Natural Fiber Reinforcement in Polylactic Acid Biocomposites.

This paper is focused on the flexural properties of bleached kraft softwood fibers, bio-based, biodegradable, and a globally available reinforcement commonly used in papermaking, of reinforced polylactic acid (PLA) composites. The matrix, polylactic acid, is also a bio-based and biodegradable polymer. Flexural properties of composites incorporating percentages of reinforcement ranging from 15 to 30 wt % were measured and discussed. Another objective was to evaluate the strength of the interface between the matrix and the reinforcements, using the rule of mixtures to determine the coupling factor. Nonetheless, this rule of mixtures presents two unknowns, the coupling factor and the intrinsic flexural strength of the reinforcement. Hence, applying a ratio between the tensile and flexural intrinsic strengths and a defined fiber tensile and flexural strength factors, derived from the rule of mixtures is proposed. The literature lacks a precise evaluation of the intrinsic tensile strength of the reinforcements. In order to obtain such intrinsic tensile strength, we used the Kelly and Tyson modified equation as well as the solution provided by Bowyer and Bader. Finally, we were able to characterize the intrinsic flexural strengths of the fibers when used as reinforcement of polylactic acid.

Lyman-ß narrowband coatings with strong Lyman-α rejection.

Novel narrowband multilayer coatings efficient at a wavelength as short as 100 mn are presented, which pushes shortwards the existing limit of reported narrowband multilayers. Such limit had been established at ~120 nm, close to the MgF2 cutoff wavelength. The new multilayers combine layers of Al, LiF, and SiC, in an Al/LiF/SiC/LiF multilayer design (four layers, starting with the innermost layer). Among these materials, Al and LiF are deposited by evaporation and SiC by ion-beam-sputtering. In addition to a high, narrow peak close to H Lyman ß (102.6 nm), these multilayers simultaneously provide a very small reflectance at H Lyman α (121.6 nm). This combined performance is demanded in space instrumentation for astrophysics and solar physics observations among others, where imaging the sky at the important diagnostic spectral line of Lyman ß line requires rejecting the frequently much more intense background at Lyman α line. Such is the case for solar corona observations at Lyman ß, which is masked by the strong Lyman α line. The multilayer peak is placed close to another important diagnostic tool: the OVI doublet at 103.2 and 103.8 nm. The target of small reflectance at 121.6 nm was seen to be the most critical. The best strategy in multilayer preparation was to prepare it with such minimum reflectance at slightly shorter wavelengths so that the coating evolved to shift it longwards over time. Multilayers kept a remarkable 102.6 nm/121.6 nm reflectance ratio over time in spite of some performance degradation. Hence, a multilayer coating aged of 4 years kept a reflectance of 43% at 102.6 nm and 0.2% at 121.6 nm.

Optimization of MgF2-deposition temperature for far UV Al mirrors.

Progress towards far UV (FUV) coatings with enhanced reflectance is invaluable for future space missions, such as LUVOIR. This research starts with the procedure developed to enhance MgF2-protected Al reflectance through depositing MgF2 on a heated aluminized substrate [Quijada et al., Proc. SPIE 8450, 84502H (2012)] and it establishes the optimum deposition temperature of the MgF2 protective film for Al mirrors with a reflectance as high as ~90% at 121.6 nm. Al films were deposited at room temperature and protected with a MgF2 film deposited at various temperatures ranging from room temperature to 350°C. It has been found that mirror reflectance in the short FUV range continuously increases with MgF2 deposition temperature up to 250°C, whereas reflectance decreases at temperatures of 300°C and up. The short-FUV reflectance of mirrors deposited at 250°C only slightly decreased over time by less than 1%, compared to a larger decay for standard coatings prepared at room temperature. Al mirrors protected with MgF2 deposited at room temperature that were later annealed displayed a similar reflectance enhancement that mirrors protected at high temperatures. MgF2 and Al roughness as well as MgF2 density were analyzed by x-ray grazing incidence reflectometry. A noticeable reduction in both Al and MgF2 roughness, as well as an increase of MgF2 density, were measured for films deposited at high temperatures. On the other hand, it was found a strong correlation between the protective-layer deposition temperature (or post-deposition annealing temperature) and the pinhole open area in Al films, which could be prevented with a somewhat thicker Al film.

Relación entre sistemas de costes y gasto hospitalario / Relationship between cost systems and hospital expenditure

Objetivo: Analizar la relación entre el grado de desarrollo de los sistemas de costes (SC) hospitalarios implantados por los servicios regionales de salud (SRS) y la variación del coste unitario de los hospitales del Sistema Nacional de Salud (SNS) español entre 2010 y 2013, e identificar otros factores explicativos de dicha variación. Métodos: Se construyó una base de datos de los hospitales del SNS a partir de fuentes exclusivamente públicas. Se emplea un modelo de regresión multinivel para analizar los factores explicativos de la variación en el coste unitario (coste por unidad ponderada de actividad [UPA]) de una muestra de 170 hospitales. Resultados: Las variables representativas del grado de desarrollo del SC se asocian de forma negativa y significativa con la variación del coste por UPA. Se observa que, si se utiliza un SC de alto grado de desarrollo, la variación del coste por UPA experimentaría una reducción próxima al 3,2%. También se encuentra una relación negativa y significativa entre la variación del coste por UPA y las variaciones en el porcentaje de alta tecnología y el índice de ocupación. Por otra parte, la evolución del coste por UPA se asocia de forma positiva y significativa con las variaciones en el coste medio de personal y en el número de trabajadores por 100 camas. Conclusión: En el periodo analizado, años en los que se realizó el principal ajuste del gasto sanitario, el control del coste unitario hospitalario está asociado no solo con los recortes de gasto, sino también con aspectos vinculados a la gestión, tales como la implantación de SC más desarrollados (AU)

Objective: To analyze the relationship between the degree of development of hospital cost systems (CS) implemented by the regional health services (RHS) and the variation in unit cost of hospitals in Spanish National Health Service (NHS) between 2010 and 2013 and to identify other explanatory factors of this variation. Methods: A database of NHS hospitals was constructed from exclusively public sources. Using a multilevel regression model, explaining factors of the variation in unit cost (cost per weighted unit of activity [WAU]) of a sample of 170 hospitals were analyzed. Results: The variables representative of the degree of development of CS are associated in a negative and significant way with the variation of the cost per WAU. It is observed that if a high-level development CS is used the cost variation per WAU would be reduced by close to 3.2%. There is also a negative and significant relationship between the variation in the cost per WAU and the variations in the percentage of high technology and the hospital occupancy rate. On the other hand, the variations in the average cost of personnel and in the number of workers per 100 beds are associated in a positive and significant way with the variation of the cost per WAU. Conclusion: In the period analysed, during which the main health expenditure adjustment was made, the control in hospital unit cost is associated not only with spending cuts but also with aspects related to their management, such as the implementation of more developed CS (AU)

Assessing the effect of standardized cost systems on financial performance. A difference-in-differences approach for hospitals according to their technological level.

Promoting the improvement of standardized cost systems (CS) is one of the measures available to health policy makers for the purpose of improving efficiency in hospitals over the long-term. Nevertheless, very few studies evaluate the relationship between alternative CS and the costs really incurred. We use data from 242 hospitals of the Spanish National Health Service (NHS) between 2010 and 2013 in order to explore the determinants of the cost per adjusted patient day, using a difference-in-differences approach where the treatment is the implementation of an advanced CS. We also investigate if the association between advanced CS and unit cost is different depending upon the technological level of the hospital. Results show that hospitals with more advanced CS contained their costs better. However, the latter effect of advanced CS is lower in hospitals with a greater endowment of high technology. Results suggest that health authorities should support the development of CS, particularly in high-tech hospitals, which are usually larger and more complex hospitals that tend to accumulate a greater portion of NHS hospital sector expenditure.

[Relationship between cost systems and hospital expenditure]. / Relación entre sistemas de costes y gasto hospitalario.

OBJECTIVE: To analyze the relationship between the degree of development of hospital cost systems (CS) implemented by the regional health services (RHS) and the variation in unit cost of hospitals in Spanish National Health Service (NHS) between 2010 and 2013 and to identify other explanatory factors of this variation. METHODS: A database of NHS hospitals was constructed from exclusively public sources. Using a multilevel regression model, explaining factors of the variation in unit cost (cost per weighted unit of activity [WAU]) of a sample of 170 hospitals were analyzed. RESULTS: The variables representative of the degree of development of CS are associated in a negative and significant way with the variation of the cost per WAU. It is observed that if a high-level development CS is used the cost variation per WAU would be reduced by close to 3.2%. There is also a negative and significant relationship between the variation in the cost per WAU and the variations in the percentage of high technology and the hospital occupancy rate. On the other hand, the variations in the average cost of personnel and in the number of workers per 100 beds are associated in a positive and significant way with the variation of the cost per WAU. CONCLUSION: In the period analysed, during which the main health expenditure adjustment was made, the control in hospital unit cost is associated not only with spending cuts but also with aspects related to their management, such as the implementation of more developed CS.

Bleached Kraft Eucalyptus Fibers as Reinforcement of Poly(Lactic Acid) for the Development of High-Performance Biocomposites.

Poly(lactic acid) (PLA) is one of the most well-known biopolymers. PLA is bio-based, biocompatible, biodegradable, and easy to produce. This polymer has been used to create natural fiber reinforced composites. However, to produce high-performance and presumably biodegradable composites, the interphase between PLA and natural fibers still requires further study. As such, we aimed to produce PLA-based composites reinforced with a commercial bleached kraft eucalyptus pulp. To become a real alternative, fully biodegradable composites must have similar properties to commercial materials. The results found in this research support the competence of wood fiber reinforced PLA composites to replace other glass fiber reinforced polypropylene composites from a tensile property point of view. Furthermore, the micromechanics analysis showed that obtaining strong interphases between the PLA and the reinforcement is possible without using any coupling agent. This work shows the ability of totally bio-based composites that fulfill the principles of green chemistry to replace composites based on polyolefin and high contents of glass fiber. To the best knowledge of the authors, previous studies obtaining such properties or lower ones involved the use of reagents or the modification of the fiber surfaces.

Transmittance and optical constants of Ca films in the 4-1000 eV spectral range.

The low expected absorption of Ca in the extreme ultraviolet (EUV) makes it an attractive material for multilayers and filters because most materials in nature strongly absorb the EUV. Few optical constant data had been reported for Ca. In this research, Ca films of various thicknesses were deposited on grid-supported C films and their transmittance measured in situ from the visible to the soft x-rays. The measurement range contains M2,3 and L2,3 absorption edges. Transmittance measurements were used to obtain the Ca extinction coefficient k. A minimum k of 0.017 was obtained at ∼23 eV, which makes Ca a promising low-absorption material for EUV coatings. A second spectral range of interest for its low absorption is below the Ca L3 edge at ∼343 eV. Measured k data and extrapolations were used to calculate the refractive index n using Kramers-Krönig relations. This is the first self-consistent data set on Ca covering a wide spectral range including the EUV.

Molecular mechanisms involved in the response to desiccation stress and persistence in Acinetobacter baumannii.

Desiccation tolerance contributes to the maintenance of bacterial populations in hospital settings and may partly explain its propensity to cause outbreaks. Identification and relative quantitation of proteins involved in bacterial desiccation tolerance was made using label-free quantitation and iTRAQ labeling. Under desiccating conditions, the population of the Acinetobacter baumannii clinical strain AbH12O-A2 decreased in the first week, and thereafter, a stable population of 0.5% of the original population was maintained. Using label-free quantitation and iTRAQ labeling, 727 and 765 proteins, respectively, were detected; 584 of them by both methods. Proteins overexpressed under desiccation included membrane and periplasmic proteins. Proteins associated with antimicrobial resistance, efflux pumps, and quorum quenching were overexpressed in the samples subjected to desiccation stress. Electron microscopy revealed clear morphological differences between desiccated and control bacteria. We conclude that A. baumannii is able to survive long periods of desiccation through the presence of cells in a dormant state, via mechanisms affecting control of cell cycling, DNA coiling, transcriptional and translational regulation, protein stabilization, antimicrobial resistance, and toxin synthesis, and that a few surviving cells embedded in a biofilm matrix are able to resume growth and restore the original population in appropriate environmental conditions following a "bust-and-boom" strategy.

Estudio de algunos sueños infantiles en Miau de Galdós / A study of children´s dreams in Galdos´s MIAU: The dreams of Luisito Cadalso

Galdós, el gran novelista español del siglo XIX, es considerado por numerosos críticos como un freudiano avant la lettre, debido a un interés por los sueños, que utiliza para dar profundidad a los personajes. En el presenta artículo se trabajan algunos sueños de la novela Miau: en concreto los sueños de un niño, Luisito Cadalso. Sueños que, en nuestra opinión, están, por una parte, determinados por la llamada por algunos autores (Fairbairn, Killingmo, etc) culpa secundaria y, por otra, sirven, en la línea de Ferenczi, para elaborar los avatares que la vida le trae al personaje de Luisito (AU)

Galdós, the great Spanish novelist of the 19th century, is considered by numerous critics as and avant la lettre Freudian given his interest in dreams, which he used to provide depth to his characters. In this paper, several dreams from the novel Miau are examined: in particular, the dreams of a boy named Luisisto Cadalso. These dreams, in our opinion, are on the one hand determined by what some authors (e.g., Fairbairn, Killingmo, etc) call secondary guilt and, on the other, they serve, following the lines of Ferenczi, to elaborate the avatars of life of the character Luisisto (AU)

Triple-wavelength, narrowband Mg/SiC multilayers with corrosion barriers and high peak reflectance in the 25-80 nm wavelength region.

We have developed new, Mg/SiC multilayer coatings with corrosion barriers which can be used to efficiently and simultaneously reflect extreme ultraviolet (EUV) radiation in single or multiple narrow bands centered at wavelengths in the spectral region from 25 to 80 nm. Corrosion mitigation was attempted through the use of Al-Mg or Al thin layers. Three different multilayer design concepts were developed and deposited by magnetron sputtering and the reflectance was measured at near-normal incidence in a broad spectral range. Standard Mg/SiC multilayers were also deposited and measured for comparison. They were shown to efficiently reflect radiation at a wavelength of 76.9 nm with a peak reflectance of 40.6% at near-normal incidence, the highest experimental reflectance reported at this wavelength for a narrowband coating. The demonstration of multilayer coatings with corrosion resistance and multiple-wavelength EUV performance is of great interest in the development of mirrors for space-borne solar physics telescopes and other applications requiring long-lasting coatings with narrowband response in multiple emission lines across the EUV range.

Self-consistent optical constants of sputter-deposited B4C thin films.

The optical constants of ion-beam-sputtered B4C films have been measured by ellipsometry in the 190-950 nm range. The set of data has been extended toward both shorter and longer wavelengths with data in the literature, along with interpolations and extrapolations, in order to obtain a self-consistent set of data by means of Kramers-Krönig analysis. All data correspond to films that were deposited by sputtering on nonheated substrates, and hence they are expected to be amorphous. The B4C bandgap was calculated as a fitting parameter of Tauc equations for indirect transitions using the present optical constants. Good global accuracy of the data was estimated through the use of various sum rules. The consistent data set includes the visible to the extreme UV (EUV); this large spectrum of characterization will enable the design of multilayer coatings that combine a relatively high reflectance in parts of the EUV with a desired performance at a secondary range, such as the visible.

Self-consistent optical constants of SiC thin films.

The optical constants of ion-beam-sputtered SiC films have been measured by ellipsometry in the 190 to 950 nm range. The set of data has been extended both toward shorter and longer wavelengths with data in the literature, along with inter- and extrapolations, in order to obtain a self-consistent set of data by means of Kramers-Krönig analysis. All data correspond to films that were deposited by sputtering on nonheated substrates, and hence they are expected to be amorphous. A bandgap of 1.9 eV for the films was fitted from the obtained optical constants. A good global accuracy of the data was estimated through the use of various sum rules. The consistent dataset includes the visible to the extreme ultraviolet (EUV); this large spectrum of characterization will enable the design of multilayer coatings that combine a high reflectance in parts of the EUV with desired performance at a secondary range, such as the visible. To our knowledge, this paper provides the first compilation of the optical constants of amorphous SiC films.