Age norms for grating acuity and contrast sensitivity in children using eye tracking technology

Key messages: Visual acuity is the most used method to assess visual function in children. Contrast sensitivity complements the information provided for visual acuity, but it is not commonly used in clinical practice. Digital devices are increasingly used as a method to evaluate visual function, due to multiple advantages. Testing with these devices can improve the evaluation of visual development in children from a few months of age. Visual acuity and contrast sensitivity tests, using eye tracking technology, are able to measure visual function in children across a wide range of ages, objectively, quickly and without need of an experienced examiner. Purpose: To report age-normative values for grating visual acuity and contrast sensitivity in healthy children using a digital device with eye tracking technology and to validate the grating acuity test. Methods: In the first project of the study, we examined healthy children aged between 6 months and 7 years with normal ophthalmological assessment. Grating visual acuity (VA) and contrast sensitivity (CS) were assessed using a preferential gaze paradigm with a DIVE (Device for an Integral Visual Examination) assisted with eye tracking technology to provide age norms. For the validation project, we compared LEA grating test (LGT) with DIVE VA in a group of children aged between 6 months and 4 years with normal and abnormal visual development. Results: Fifty-seven children (2.86 ± 1.55 years) were examined with DIVE VA test and 44 successfully completed DIVE CS test (3.06 ± 1.41 years). Both, VA and CS values increased with age, mainly along the first two years of life. Sixty-nine patients (1.34 ± 0.61 years) were included in the DIVE VA test validation. The mean difference between LGT and DIVE VA was − 1.05 ± 4.54 cpd with 95% limits of agreement (LoA) of − 9.95–7.84 cpd. Agreement between the two tests was higher in children younger than 1 year with a mean difference of − 0.19 ± 4.02 cpd. Conclusions: DIVE is an automatic, objective and reliable tool to assess several visual function parameters in children, and it has good agreement with classical VA tests, especially for the first stage of life

Effects of hospital facilities on patient outcomes after cancer surgery: an international, prospective, observational study

Background Early death after cancer surgery is higher in low-income and middle-income countries (LMICs) compared with in high-income countries, yet the impact of facility characteristics on early postoperative outcomes is unknown. The aim of this study was to examine the association between hospital infrastructure, resource availability, and processes on early outcomes after cancer surgery worldwide.Methods A multimethods analysis was performed as part of the GlobalSurg 3 study-a multicentre, international, prospective cohort study of patients who had surgery for breast, colorectal, or gastric cancer. The primary outcomes were 30-day mortality and 30-day major complication rates. Potentially beneficial hospital facilities were identified by variable selection to select those associated with 30-day mortality. Adjusted outcomes were determined using generalised estimating equations to account for patient characteristics and country-income group, with population stratification by hospital.Findings Between April 1, 2018, and April 23, 2019, facility-level data were collected for 9685 patients across 238 hospitals in 66 countries (91 hospitals in 20 high-income countries; 57 hospitals in 19 upper-middle-income countries; and 90 hospitals in 27 low-income to lower-middle-income countries). The availability of five hospital facilities was inversely associated with mortality: ultrasound, CT scanner, critical care unit, opioid analgesia, and oncologist. After adjustment for case-mix and country income group, hospitals with three or fewer of these facilities (62 hospitals, 1294 patients) had higher mortality compared with those with four or five (adjusted odds ratio [OR] 3.85 [95% CI 2.58-5.75]; p<0.0001), with excess mortality predominantly explained by a limited capacity to rescue following the development of major complications (63.0% vs 82.7%; OR 0.35 [0.23-0.53]; p<0.0001). Across LMICs, improvements in hospital facilities would prevent one to three deaths for every 100 patients undergoing surgery for cancer.Interpretation Hospitals with higher levels of infrastructure and resources have better outcomes after cancer surgery, independent of country income. Without urgent strengthening of hospital infrastructure and resources, the reductions in cancer-associated mortality associated with improved access will not be realised

The electronic structure of oxide-supported tungsten oxide catalysts as studied by UV spectroscopy

The UV spectra of tungsten oxide catalysts supported on alumina, titania and zirconia and on titania-alumina and titania-zirconia mixed oxides are reported and discussed. Evidence is provided for the different electronic structure of supports and catalysts, which could affect the behavior of the tungsten oxide centres in the different cases. On alumina, tungsten oxide centres are "isolated" by the insulating support, while on titania-based materials they are likely in electronic contact with each other and with Ti centres through the support conduction band. In the case of WO3-ZrO2, the 5d levels of tungsten ions fall just below of the lower energy limit of the support conduction band

A vibrational and spectroscopic study of WO3/TiO2-Al2O3 catalyst precursors

WO3/TiO2-Al2O3 catalyst powders with titania-alumina mixed oxides synthesized by a sol-gel procedure have been prepared by dry impregnation. The surface structure of the resulting materials has been investigated by In and Raman spectroscopies in the skeletal region and IR spectra of adsorbed water and ammonia; Iris concluded that the largely predominant tungsten species, when these are below the monolayer coverage slid in dry conditions, on all the supports studied, are constituted by monooxo wolframyl species which are coordinatively unsaturated and act as strong Lewis acid sites. The overall coordination around tungsten is consequently 4 and/or 5. By adsorption of water, the overall coordination of tungsten grows and the site behaves as a strong Bronsted acid site. The vibrational behavior of such species suggests that the W=O vibrators: are uncoupled, which means that they belong to isolated molecular units anchored to the surface by W-O-(Ti,Al) bonds, without significant extent of W-O-W bridges. The nature of the support surface significantly modifies the strength of the W=O bond, which is indicative of the electronic state of tungsten. This is attributed to the different basicity of the surface oxide ions that act as the ligands of the wolframyl ion. The support surface hydroxy groups apparently do not play an important role in anchoring the wolframyl species. The "monolayer capacity" of the supports apparently depends quite strongly on the support nature, and it seems that care should be taken with its calculation, to compare on the same basis the results arising from different laboratories

Hydroconversion of hydrocarbons over HZSM5 and Mo-HZSM5 catalysts: A FTIR and flow reactor study

The interactions of n-heptane, benzene, and toluene with HZSM5 and Mo-HZSM5 catalysts were studied by FTIR spectroscopy. The results from the FTIR study on the interactions of single molecules with these catalysts are compared with the product distribution results obtained during the hydroconversion of a model mixture of n-heptane-benzene-toluene over HZSM5-alumina and Mo-HZSM5-alumina catalysts. The FTIR study indicates that there are interactions of heptane, benzene, and toluene with both the strongly acidic internal OH's and the less acidic silanol groups in HZSM5. These interactions seem to be a precursor for the formation of carbenium ions, which are the active species in hydroconversion reactions. The incorporation of Mo into HZSM5 causes a strong decrease in the number of external silanols, suggesting that some of the impregnated Mo species are located at the external zeolite surface. It is also evident from the FTIR results that the incorporation of Mo does not entirely destroy or exchange the internal OH's of HZSM5. The addition of Mo to the zeolite, in addition to causing a decrease in the overall conversion of heptane, causes a marked simplification in the pattern of the main reaction products. The cracking and alkylation functionalities of the catalyst are almost suppressed, whereas a significant increase in skeletal isomerization is observed. This suggests, in line with the FTIR experiments, that the incorporation of Mo into the HZSM5-alumina catalyst causes a decrease in the availability of the strong Bronsted acid sites located in the cavities of the zeolite

A FT-IR study of the adsorption of indole, carbazole, benzothiophene, dibenzothiophene and 4,6-dibenzothiophene over solid adsorbents and catalysts

The adsorption of benzothiophene (BT), dibenzothiophene (DBT), 4,6-dimethyldibenzothiophene (DMDBT), dibenzofuran (DBF). indole (IND) and carbazole (CARB) on alumina, zirconia and magnesia has been studied by IR spectroscopy. The main adsorption process is due to adsorption on Lewis sites or on acid-base pairs. On alumina the adsorption is strongest, desorption being not obtained above 723 K. BT also undergoes a transformation with likely the heteroaromatic ring opening. Adsorption of 4,6-DBT is definitely limited in extent likely due to steric hindrance. The N-containing compounds IND and CARB are adsorbed dissociatively with breaking of the NH bond. (C) 2002 Elsevier Science B.V. All rights reserved

Characterization of alumina-titania mixed oxide supports - Part II: Al2O3-based supports

Bulk and surface characterization of alumina-rich Al2O3-TiO2 mixed oxides with TiO2/(Al2O3 + TiO2) molar ratios equal to 0, 0.05 and 0.1, prepared by sol-gel and impregnation procedures have been performed by XRD, DTA, surface area, FTIR, UV-Vis, FT-Raman and TPD of ammonia. The results indicate that in the case of the samples prepared by the sol-ger procedure, an increase in surface area with titania loadings is obtained, in contrast to their impregnation counterparts, where a decrease is observed. The results from XRD, Raman and UV-Vis indicate that better titania dispersions are obtained by the sol-gel procedure and that at the titania loadings used here, no separate titania particles are detected. Additionally, the UV results show that Ti cations are essentially isolated, possibly into an octahedral form and with a lower coordination. In the samples prepared by the sol-gel procedure there is no evidence of titanium oxide species on the surface, suggesting that titania is probably dissolved into the alumina bulk. These results would explain the activity trends observed in alumina-rich Mo/Al2O3-TiO2 HDS catalysts. (C) 1998 Elsevier Science B.V. All rights reserved

Surface Changing Accommodating Intraocular Lens with Photobonded Haptic Engagement

San Jose, California, United States of America, February 24 - 25, 2017Peer Reviewe