Degeneration Behavior of Cu Nanowires under Carbon Dioxide Environment: An In Situ/Operando Study.

Copper (Cu) is a catalyst broadly used in industry for hydrogenation of carbon dioxide, which has broad implications for environmental sustainability. An accurate understanding of the degeneration behavior of Cu catalysts under operando conditions is critical for uncovering the failure mechanism of catalysts and designing novel ones with optimized performance. Despite the widespread use of these materials, their failure mechanisms are not well understood because conventional characterization techniques lack the necessary time and spatial resolution to capture these complex behaviors. In order to overcome these challenges, we carried out transmission electron microscopy (TEM) with a specialized in situ gas environmental holder, which allows us to unravel the dynamic behavior of the Cu nanowires (NWs) in operando. The failure process of these nanoscale Cu catalysts under CO2 atmosphere were tracked and further rationalized based on our numerical modeling using phase-field methods.

Combining analytical and in vitro techniques for comprehensive assessments of chemical exposure and effect in green sea turtles (Chelonia mydas).

Sea turtle populations foraging in coastal areas adjacent to human activity can be exposed to numerous chemical contaminants for long periods of time. For trace elements, well-developed, sensitive and inexpensive analytical techniques remain the most effective method for assessing exposure in sea turtles. However, there are many thousands more organic contaminants present in sea turtles, often at low levels as complex mixtures. Recently developed species-specific in vitro bioassays provide an effective means to identify the presence, and effect of, organic chemicals in sea turtles. This study used a combination of chemical analysis and effects-based bioassays to provide complementary information on chemical exposure and effects for three green turtle foraging populations (Chelonia mydas) in southern Queensland, Australia. Blood was collected from foraging sub-adult green turtles captured in Moreton Bay, Hervey Bay, and Port Curtis. Twenty-six trace elements were measured in whole blood using ICP-MS. Organic contaminants in turtle blood were extracted via QuEChERS and applied to primary green turtle skin fibroblast cell in vitro assays for two toxicity endpoints; cytotoxicity and oxidative stress. The trace element analysis and bioassay results indicated site-specific differences between foraging populations. In particular, turtles from Moreton Bay, a heavily populated coastal embayment, had pronounced cytotoxicity and oxidative stress from organic blood extracts, and elevated concentrations of Cs, Ag, and Zn relative to the other sites. Incorporating traditional chemical analysis with novel effects-based methods can provide a comprehensive assessment of chemical risk in sea turtle populations, contributing to the conservation and management of these threatened species.

Cu-Substituted NiF2 as a Cathode Material for Li-Ion Batteries.

Metal fluorides usually have a large electronegativity and are promising electrode materials for high-power lithium-ion batteries. However, like other conversion-reaction-based materials, large volumetric expansions and large capacity losses in cycling are the major issues for metal fluorides. Here, we explore substitution of Ni with Cu for binary NiF2 and its effects on the electrochemical properties. By in situ transmission electron microscopy, the structural evolutions of several ternary metal fluorides with different Cu/Ni ratios are observed and correlated with their electrochemical properties. With increased Cu substitution from 0 to 25 wt %, the areal expansion during the first lithiation is reduced. Meanwhile, the fluorine loss (due to reaction irreversibility) in the delithiation cycle is also reduced. This provides an explanation for the advantage of Cu substitution for improved cycling stability and capacity. We believe that our observations provide insight into the development of better ternary metal fluorides as cathodes for high power density lithium-ion batteries.

Multidisciplinariedad, interdisciplinariedad y transdisciplinariedad en la formación para la investigación en ingeniería *

En el presente texto, se dan a conocer aspectos relevantes de la formación en investigación en la Facultad de Ingeniería de la Corporación Universitaria Americana. En primer lugar, se estudian los conceptos de Multidisciplinariedad, Interdisciplinariedad y Transdisciplinariedad desde su relación con la formación. En segundo lugar, se identifica el nivel de influencia de las percepciones de estudiantes en los procesos de formación en Investigación a la luz de la Estrategia de Formación por Proyectos mediante un análisis exploratorio de los resultados obtenidos de una encuesta de evaluación de una actividad transdisciplinar denominada "foro de lecciones aprendidas". Como conclusión de los resultados de la investigación, se identifica la independencia entre semestre y el concepto que los estudiantes tienen acerca de su formación por competencias en relación al foro y se proponen estrategias de intervención en este aspecto.

Introduction. Nowadays, engineering schools are faced with complex needs in realities that are often alien to them and transcend disciplinary limits. The efforts to understand this result in the implementation of conceptualization spaces oriented towards the articulation of processes coherent with the institutional work and the policies of accreditation in high quality. Objective. To analyze relevant aspects of research training in the School of Engineering of the American University Corporation considering the challenges imposed by the disciplinary, multidisciplinary interdisciplinary, and / or transdisciplinary tensions of sciences. Materials and methods. Disciplinarity, Multidisciplinarity, Interdisciplinarity, and Transdisciplinarity concepts are studied from their relationship with training. Subsequently, perceptions of students in research training processes are identified through an exploratory analysis of results obtained from an evaluation survey of a transdisciplinary activity called "lessons learned forum," the analysis was carried out using a chi-square test with a 95% reliability for a sample of 200 students of the Engineering School for the year 2016. Results. Taking into account the rejection of independence for 24 2 36,4 , in which 24 represent the degrees of freedom with a 5% error, the initial hypothesis is retained. Conclusion: There is an independence between the semester and students' concept about their training by competences in relation to the forum, which entails the need to propose intervention strategies for the transgression of what is disciplinary and to promote complex thinking in students.

Introdução. Atualmente, as faculdades de engenharia se encontram ante necessidades complexas em realidades que muitas vezes são alheias a elas e transcendem os limites do disciplinar. Os esforços por compreender este, derivam na implementação de espaços de conceptualização orientados para a articulação de processos coerentes com o trabalho institucional e as políticas de acreditação em alta qualidade. Objetivo. Analisar aspectos relevantes da formação em investigação na Faculdade de Engenharia da Corporação Universitária Americana considerando os desafios que impõem as tensões entre o disciplinar, multidisciplinar, interdisciplinar e/ou transdisciplinar das ciências. Materiais e métodos. Se estudam os conceitos de Disciplinariedade, Multidisciplinariedade, Interdisciplinariedade e Transdisciplinariedade desde sua relação com a formação. Posteriormente, se identificam percepções de estudantes em processos de formação em Investigação mediante uma análise exploratório dos resultados obtidos de uma enquete de avaliação de uma atividade transdisciplinar denominada "foro de lições aprendidas", a análise se realizou mediante uma prova chi-quadrado com uma confiabilidade de 95% para uma amostra de 200 estudantes da faculdade de engenharia para o ano 2016. Resultados. Tendo em conta a rejeição de independência para 24 2 36,4, onde 24, representam os graus de liberdade com um erro de 5 % , se conserva a hipótese inicial. Conclusão. Existe independência entre semestre e o conceito dos estudantes sobre da sua formação por competências em relação ao foro, o qual implica à necessidade de propor estratégias de intervenção para a transgressão do disciplinar e potenciar o pensamento complexo nos estudantes.

Levels of arsenic, cadmium, lead and mercury in the branchial plate and muscle tissue of mobulid rays.

Mobulid rays are targeted in fisheries for their branchial plates, for use in Chinese medicine. Branchial plate and muscle tissue from Mobula japanica were collected from fish markets in Sri Lanka, and muscle tissue biopsies from Manta alfredi in Australia. These were analysed for arsenic, cadmium, lead and mercury and compared to maximum levels (MLs) set by Food Standards Australia and New Zealand (FSANZ), European Commission (EC) and Codex Alimentarius Commission. The estimated intake for a vulnerable human age group was compared to minimal risk levels set by the Agency for Toxic Substances and Disease Registry. The mean inorganic arsenic concentration in M. japanica muscle was equivalent to the FSANZ ML while cadmium exceeded the EC ML. The mean concentration of lead in M. alfredi muscle tissue exceeded EC and Codex MLs. There were significant positive linear correlations between branchial plate and muscle tissue concentrations for arsenic, cadmium and lead.

Visual quality after monovision correction by laser in situ keratomileusis in presbyopic patients.

PURPOSE: To evaluate visual quality after laser in situ keratomileusis (LASIK) performed to achieve monovision in presbyopic patients. SETTING: Laboratory of Vision Sciences and Applications, Department of Optics, University of Granada, Granada, and Clínica Novovisión, Madrid, Spain. DESIGN: Cohort study. METHODS: Laser in situ keratomileusis was performed with the Allegretto Wave Eye-Q 400 Hz laser. The dominant eye was corrected for far vision and the nondominant eye for near vision by targeting -1.25 diopters of myopia. The F-CAT algorithm was programmed targeting a postsurgical corneal asphericity of -0.80 in the dominant eye and -1.00 in the nondominant eye. Visual acuity, contrast sensitivity function, ocular aberrations, stereoacuity, the scattering index, and the visual-discrimination capacity were analyzed preoperatively and 3 months postoperatively. RESULTS: The study enrolled 25 patients (50 eyes) with a mean age of 49.3 years ± 4.5 (SD). Postoperatively, more than 90% of patients had a binocular uncorrected distance and near visual acuity of 0.0 logMAR or better, although the contrast sensitivity function diminished, especially in the nondominant eye and with binocular vision. Stereoacuity was significantly worse in all patients (P<.001). The visual discrimination capacity declined in nondominant eyes and under binocular conditions (P<.005); no significant changes occurred in dominant eyes (P=.614). In all eyes, the mean objective scatter index value increased postoperatively, but not significantly (P>.05). CONCLUSIONS: Monovision correction by LASIK improved functional near vision in presbyopic patients. Although visual acuity was good for far vision, contrast sensitivity and stereoacuity diminished significantly.

Optical quality and visual discrimination capacity after myopic LASIK with a standard and aspheric ablation profile.

PURPOSE: To determine whether the eye's optical quality is correlated to the visual discrimination capacity of patients treated with LASIK using two different ablation algorithms. METHODS: Visual discrimination was evaluated by the disturbance index under low illumination (Halo v1.0 software, Laboratory of Vision Sciences and Applications) in two groups of patients who underwent LASIK with two different ablation algorithms using the Allegretto Wave Eye-Q 400 Hz laser (WaveLight AG). In the first group (standard group; 30 eyes), corneal ablations were performed with the standard algorithm (preoperative spherical equivalent refraction -3.20±1.70 diopters [D]). In the second group (Q-optimized group; 38 eyes; spherical equivalent refraction -3.40±1.90 D), the ablations were made with the Q-optimized (F-CAT) algorithm. Optical quality of the eye was calculated by the Strehl ratio measured with a double-pass device (OQAS, Visiometrics SL). RESULTS: After LASIK, both the Strehl ratio as well as visual discrimination capacity diminished in both groups, although the changes were significantly greater in the standard group than in the Q-optimized group. CONCLUSIONS: A high correlation was found between the Strehl ratio and the disturbance index in patients who underwent LASIK, regardless of the ablation algorithm applied. Optical and visual deterioration were greater after standard ablation.

Keratoconus-integrated characterization considering anterior corneal aberrations, internal astigmatism, and corneal biomechanics.

PURPOSE: To evaluate the clinical features of keratoconus taking into consideration anterior corneal aberrations, internal astigmatism, and corneal biomechanical properties and to define a new grading system based on visual limitation. SETTING: Vissum Corporation, Alicante, Spain. DESIGN: Retrospective case series. METHODS: This multicenter study comprised consecutive keratoconic eyes with no previous ocular surgery or active ocular disease. Visual, refractive, corneal topography, and pachymetry outcomes were analyzed. Internal astigmatism was calculated by vectorial analysis. Corneal aberrations and corneal biomechanics characterized by the Ocular Response Analyzer were evaluated in some eyes. Correlations between clinical data and a linear multiple regression analysis for characterizing the relationship between visual limitation and objective clinical data were performed. RESULTS: This study comprised 776 eyes of 507 patients (age range 11 to 79 years) The mean keratometry (K) correlated significantly with logMAR corrected distance visual acuity (CDVA) (r = 0.591, P<.01), internal astigmatism (r = 0.497, P<.01), corneal asphericity (r = -0.647, P<.01), and several corneal higher-order aberrometric coefficients (r≥0.603, P<.01). Significant correlations were found between some corneal aberrometric parameters and CDVA (r≥0.444, P<.01). Multiple regression analysis showed that CDVA was significantly correlated with the mean K, intraocular pressure, corneal resistance factor, and spherical equivalent (r(2) = 0.69, P<.01). There were significant differences in mean K, internal astigmatism, and corneal higher-order aberrations between 4 groups differentiated by visual limitation (P<.01). CONCLUSION: The visual limitation in keratoconus could be explained by different alterations that occur in these corneas and allowed development of a new grading system for this condition.

Visual performance after LASIK for a Q-optimized and a standard ablation algorithm.

We test visual performance after LASIK (laser in situ keratomileusis) for a Q-optimized ablation algorithm and one based on the Munnerlyn formula. The visual functions tested include aberrometry, monocular and binocular contrast sensitivity function (CSF), and a discrimination test under low-illumination conditions. This test is useful to quantify night-vision disturbances. A total of 102 patients took part in the experiments, and visual data were taken before (with best correction) and after LASIK. Results show a deterioration in aberrometry, CSF, binocular summation, and discrimination index for the two algorithms tested, although this deterioration is significantly lower for the Q-optimized algorithm.

Effect of LASIK and contact lens corneal refractive therapy on higher order aberrations and contrast sensitivity function.

PURPOSE: Corneal and total higher order eye aberrations and their effects on visual function were compared in two groups subjected to different emmetropization techniques-refractive surgery (LASIK) and corneal refractive therapy (CRT). METHODS: Twenty eyes of 11 patients and 22 eyes of 13 patients were examined in the CRT and LASIK groups, respectively. Mesopic contrast sensitivity function (CSF) was studied monocularly and binocularly in the two groups of patients undergoing CRT and LASIK who had approximately the same mean refractive error. Corneal asphericity and corneal and total aberrations were calculated, and the differences were analyzed between groups. Visual acuity, corneal and total ocular aberrations, corneal asphericity, and mesopic CSF were determined before and 3 months after treatment. RESULTS: In both groups, corneal and total higher order aberrations increased after treatment, and the change in some Zernike coefficients was significant. Mesopic CSF diminished after treatment under monocular as well as binocular conditions, with the greatest decline being found in the CRT group under binocular conditions. Corneal asphericity also increased significantly in both groups, which was more accentuated in the CRT group. CONCLUSIONS: Both emmetropization techniques increased higher order ocular aberrations, implying a decline in the mesopic CSF. The increase in aberrations and the consequent deterioration in visual function was more marked in the CRT group.

Night vision disturbances after successful LASIK surgery.

OBJECTIVE: To evaluate the changes in correlations of higher order aberrations of the first corneal surface with halo phenomena, a form of image degradation, under night vision conditions measured objectively after successful LASIK (laser in situ keratomileusis) surgery. METHODS: A prospective, observational, analytical study of 110 eyes that had undergone successful LASIK surgery for myopia and astigmatism. Preoperative sphere was (mean (SD)) -3.48 (1.70) D (0 to -8.00 D) and preoperative cylinder was -0.86 (0.87) D (0 to -4.00 D). Visual disturbance caused by halo phenomena was measured with the Starlights v1.0, and pupil size was measured with Colvard pupilometry after adaptation to a dark environment (0.17 lux). Corneal aberrations were computed for a corneal diameter representative of the eye's entrance pupil under night vision conditions. RESULTS: The halo disturbance index increased in this study by a factor of 2.15 after successful LASIK surgery. Total root mean square for monochromatic higher order aberration displayed a significant correlation with halo disturbance index (r = 0.42; p<0.01). However, only secondary astigmatism (r = 0.36; p<0.01), coma (r = 0.25; p = 0.02) and spherical aberration (r = 0.40; p<0.01) were responsible for such behaviour, with the remaining corneal aberrations up to the sixth order not displaying any significant correlation when considered individually. CONCLUSION: Patients undergoing LASIK procedures display an increase of halo phenomena around lights in night vision conditions, even when the results of the surgery are considered entirely satisfactory according to current international standards of predictability, efficacy and safety. Secondary astigmatism, coma and spherical aberration are the higher order aberrations up to the sixth order that significantly correlated with halo disturbance index.

Technical note: Pre-surgical anisometropia influences post-LASIK binocular mesopic contrast sensitivity function.

PURPOSE: To investigate if pre-surgical anisometropia influences the post-LASIK binocular mesopic contrast sensitivity function (CSF). METHODS: Pre- and post-surgical binocular CSF was measured for 54 patients under mesopic conditions. Data on visual acuity and corneal topography were also obtained. RESULTS: The binocular contrast sensitivity declined significantly (r = 0.86; p < 0.001) with increasing pre-surgical anisometropia. Post-surgical interocular differences in corneal asphericity were also associated with increasing pre-surgical anisometropia. CONCLUSIONS: Pre-surgical anisometropia may be indicative of a possible significant deterioration of post-surgical mesopic binocular CSF, and therefore should be taken into account before surgery in analysing the possible disadvantages and limitations of refractive surgery.

Binocular visual performance after LASIK.

PURPOSE: To analyze binocular visual function after LASIK. METHODS: Eye aberrometry and corneal topography was obtained for both eyes in 68 patients (136 eyes). To evaluate visual performance, monocular and binocular contrast sensitivity function and disturbance index for quantifying halos were measured. Tests were performed under mesopic conditions. RESULTS: Binocular summation and disturbance index diminished significantly (P<.0001) after LASIK with increasing interocular differences in corneal and eye aberrations. Binocular visual deterioration was greater than monocular deterioration for contrast sensitivity function and disturbance index. CONCLUSIONS: Binocular function deteriorates more than monocular function after LASIK. This deterioration increases as the interocular differences in aberrations and corneal shape increase. Improvements in ablation algorithms should minimize these interocular differences.

Differences between real and predicted corneal shapes after aspherical corneal ablation.

We study the differences between real and expected corneal shapes, using an aspherical ablation algorithm with a known equation and avoiding the limitation imposed by most studies of refractive surgery in which the ablation equations are not known. We have calculated the theoretical corneal shape predicted by this algorithm, comparing this shape with the real corneal topography. The results indicate that the deviations that appear in the corneal shape are significant for visual performance and for the correction of eye aberrations. If we include in this analysis the effect of reflection losses and nonnormal incidence on the cornea, we can reduce corneal differences, but they will remain significant. These results confirm that it is essential to minimize corneal differences to achieve effective correction in refractive surgery.

Simple device for quantifying the influence of halos after lasik surgery.

We present a simple device (called a halometer) to detect and quantify the phenomenon of halos after certain surgical procedures, such as refractive surgery. The task of the subject consists basically of discriminating, after dark adaptation, a small light source around a central high-luminance stimulus. The device, which is connected to a computer, provides a disturbance index to measure the effect of halos on the observer's vision. Tested with normal subjects and patients after LASIK (laser in situ keratomileusis) surgery, this apparatus proved sufficiently sensitive to quantify the halos in subjects who had undergone surgery.