Directions of high cycle fatigue cracks emanating from circular notches studied by optical profilometry

Current models for predicting the fatigue endurance of notched solids use the stresses along a straight line, beginning at the notch root, as a simplification of the real crack propagation path. In this work, the experimental crack paths for hollow notched samples were analysed through different microscopy techniques, with the objective of establishing high cycle fatigue crack growth directions in a mild steel. Fully reversed tension–compression fatigue tests of thin-walled tube specimens with a passing-through hole were carried out. The crack paths observed in the outer cylindrical surface were studied in each case, with special attention to the crack initiation point and the crack direction along the first grains. Moreover, the analysis of the fracture surfaces allowed the same analysis to be performed to determine the internal crack paths. It was observed that the crack initiation point was close to the maximum principal stress point at the hole contour as obtained from linear elastic finite element analysis, and the crack direction in its initiation was generally close to Mode I direction, contrary to the conventionally accepted 45 crack growth direction.The authors would like to thank the European Union, the Spanish Government and the Junta de Andalucía for its financial support through grantsDPI2017-84788-PandPID2020-117407GB-I00(FEDER/Ministerio de Ciencia e Innovación - Agencia Estatal de Investigación) and P18-FR- 4306 (‘‘Fondo Europeo de Desarrollo Regional (FEDER) y Consejería de Economía, Conocimiento, Empresas y Universidad de la Junta de Andalucía, dentro del Programa Operativo FEDER 2014-2020’’). N.O. Larrosa would also like to thank the UK Engineering and Physical Sciences Research Council (EPSRC) for its financial support through grant number EP/S012362/1

Relación entre la perimetría automatizada convencional y la topografía papilar realizada con el tomógrafo Heidelberg

espanolObjetivo: Determinar las correlaciones entre los parametros de la cabeza del nervio optico (CNO) obtenidos mediante el laser confocal de barrido (HRT), y los resultados de la perimetria automatizada convencional (PA) en sujetos normales, hipertensos oculares (HTO), sospechosos de glaucoma y glaucomatosos. Metodos: Cuatrocientos veintitres ojos fueron incluidos en el estudio y clasificados segun la presion intraocular basal, morfologia papilar y los resultados de la PA en 4 grupos: 87 normales, 192 hipertensos oculares, 70 sospechosos de glaucoma y 74 glaucomatosos. En los diferentes grupos diagnosticos, se calcularon los coeficientes de correlacion de Pearson entre los parametros de la CNO y la desviacion media (DM), la desviacion estandar de la media (DSM), el numero de puntos alterados en cada cuadrante del campo visual (superior-nasal, inferior-nasal, superior-temporal e inferior-temporal), el numero de puntos alterados segun los niveles de probabilidad y los valores umbral en cada punto de la PA. Resultados: En el grupo normal y de hipertensos oculares, se encontraron pocas correlaciones debiles entre los parametros del HRT y los resultados de la PA. La fuerza y el numero de correlaciones significativas aumentaron en el grupo de sospechosos de glaucoma. En el grupo de glaucomas, las correlaciones fueron mas fuertes, especialmente entre los cocientes excavacion/disco y anillo/disco con la DM (r=0,479) y entre el area de anillo con la DSM (r=0,444). Conclusiones: Se encontraron correlaciones debiles o moderadas entre algunos parametros de la CNO medidos con el HRT y los resultados de la PA, en el grupo de glaucomas. EnglishPurpose: To determine the correlations between optic nerve head (ONH) parameters measured with the Heidelberg Retina Tomograph (HRT), and the main outcomes of standard automated perimetry (SAP) in normal, ocular hypertensive, glaucoma suspects and glaucomatous subjects. Methods: Four hundred and twenty-three patients were enrolled in the study and classified into four groups depending on baseline intraocular pressure, optic nerve head morphology, and SAP results: 87 normal eyes, 192 ocular hypertensive eyes, 70 glaucoma suspects and 74 glaucomatous eyes. In the different diagnostic groups, Pearson's correlation coefficients were calculated between ONH parameters and mean deviation, pattern standard deviation (PSD), number of altered points in each quadrant of the visual field (superior-nasal, inferior-nasal, superior-temporal and inferior-temporal), number of points altered at different probability levels, and threshold values at each point of SAP. Results: In the normal and ocular hypertensive groups, only a few weak correlations were found between HRT and SAP parameters. The strength and number of significant correlations increased in the suspected glaucoma group. The glaucoma group had the strongest correlations, particularly between cup/disc ratio and rim/disc ratio with MD (r=0.479) and between rim area and PSD (r=0.444). Conclusions: Weak to moderate correlations were found between some ONH parameters obtained with the HRT and SAP results in the glaucoma grou

Continuous intraocular pressure monitoring in patients with obstructive sleep apnea syndrome using a contact lens sensor

Purpose To analyse nocturnal intraocular pressure (IOP) fluctuations in patients with obstructive sleep apnea syndrome (OSAS) using a contact lens sensor (CLS) and to identify associations between the OSAS parameters determined by polysomnographic study (PSG) and IOP changes. Method Prospective, observational study. Twenty participants suspected of having OSAS were recruited. During PSG study, IOP was monitored using a CLS placed in the eye of the patient. The patients were classified according to the apnea-hypopnea index (AHI) in two categories, severe (>30) or mild/moderate (<30) OSAS. We evaluated several parameters determined by the IOP curves, including nocturnal elevations (acrophase) and plateau times in acrophase (PTs) defined by mathematical and visual methods. Results The IOP curves exhibited a nocturnal acrophase followed by PTs of varying extents at which the IOP remained higher than daytime measurement with small variations. We found significant differences in the length of the PTs in patients with severe OSAS compared to those with mild/moderate disease (P = 0.032/P = 0.028). We found a positive correlation between PTs and OSAS severity measured by the total number of apneic events (r = 0.681/ 0.751 P = 0.004/0.001) and AHI (r = 0.674/0.710, P = 0.004/0.002). Respiratory-related arousal and oxygen saturation also were associated significantly with the IOP PT length. Conclusions Periods of nocturnal IOP elevation lasted longer in severe OSAS patients than those with mild/moderate OSAS and correlate with the severity of the disease. The length of the nocturnal PT is also associated to respiratory parameters altered in patients with OSAS

Study of association between Pre-Senile cataracts and the polymorphisms rs2228000 in XPC and rs1042522 in p53 in Spanish population

To determine if the presence of certain polymorphisms in the DNA repair gene XPC and the apoptosis inductor gene p53 is associated with pre-senile cataract development. Methods We have performed a retrospective study over three groups of patients. The group with presenile cataract formed by 72 patients younger than 55 with cataract surgery. The group with senile cataract formed by 101 patients older than 55 with cataract surgery. The group without cataract was formed by 42 subjects older than 55 without lens opacities. We analyzed the presence of SNP rs2228000 from XPC and rs1042522 from p53; and the relationship between risk factors such as smoking, alcohol intake, hypertension or diabetes. Results The comparison of the genotype distribution in XPC, within the different groups, did not show any statistically significant association in any of our analysis (p>0, 05). The comparison of the genotype distribution in p53 within the different groups did not show any statistically significant association (p>0, 05); except for the comparison between the pre-senile cataract group and the group with senile cataract where the genotype Pro/Pro (C/C) in the recessive inheritance model showed a higher risk for developing pre-senile cataract (p = 0, 031; OR = 1.04-15.97). This association decreased when we performed the analysis adjusting by the studied risk factors (p = 0.056). Conclusions Allelic variants in the gene XPC are not associated with an increased risk for developing pre-senile cataract. The presence of the genotype Pro/Pro in p53 might be associated with a major risk for developing pre-senile cataract

Therapeutical Management for Ocular Rosacea

Purpose: The purpose of this study is to describe a case of ocular rosacea with a very complex evolution. Rosacea is a chronic dermatological disease that may affect the ocular structures up to 6-72% of all cases. This form is often misdiagnosed, which may lead to long inflammatory processes with important visual consequences for affected patients. Therefore, an early diagnosis and an adequate treatment are important. Methods: We report the case of a 43-year-old patient who had several relapses of what seemed an episode of acute bacterial conjunctivitis. Two weeks later, he developed a corneal ulcer with a torpid evolution including abundant intrastromal infiltrators and calcium deposits. He was diagnosed with ocular rosacea and treated with systemic doxycycline and topical protopic. Results: A coating with amniotic membrane was placed in order to heal the ulcer, but a deep anterior lamellar keratoplasty to restore the patient''s vision because of the corneal transparency loss was necessary. Conclusions: Ocular rosacea includes multiple ophthalmic manifestations ranging from inflammation of the eyelid margin and blepharitis to serious corneal affectations. A delayed diagnosis can result in chronic inflammatory conditions including keratinization and loss of corneal transparency, which lead to important visual sequelae for affected patients. (C) 2016 The Author(s) Published by S. Karger AG, Base

Pesticide exposure and gender discrepancy in breast cancer

OBJECTIVE: It is biologically plausible that occupational and environmental pesticide exposure may contribute to breast cancer risk. Persistent chemical compounds, such as pesticides, tend to be lipophilic and are detected in human breast milk and adipose tissue. Therefore, the present systematic review ims to clarify the gender difference in breast cancer concerning pesticide exposure.MATERIALS AND METHODS: A total of 70 studies satisfied the inclusion criteria and were included in the systematic review. RESULTS: From the studies analyzed, it was observed that exposure to pesticides could be a risk factor for breast cancer in women, in particular in young women and in women who experienced menarche at a young age. In contrast, no association was found for breast cancer in men. Female breast cancer is correlated with estrogen receptor-negative tumor characteristics. Breast cancer in men was no correlated with pesticide exposure. CONCLUSIONS: Breast cancer in women has been linked to estrogen receptor positivity, but this positivity appears to be inversely related to fertility. The estrogen-like effects of organochlorine pesticides could be the cause of the observed gender differences

Evaluation of Contrast Sensitivity, Chromatic Vision, and Reading Ability in Patients with Primary Open Angle Glaucoma

Purpose. To compare contrast sensitivity, acquired color vision deficiency, and reading ability in patients with glaucoma at different stages of the disease and to establish correlations between visual field parameters and visual function scores. Methods. This prospective cross-sectional study included 121 glaucoma patients. Subjects with a diagnosis of chronic open angle glaucoma were recruited and classified according to Hodapp-Parrish-Anderson criteria. Patients with severe visual field defects were excluded because they were older, which could bias the interpretation of visual function tests. Contrast sensitivity was measured using the Pelli-Robson Chart and the CSV1000E test. Chromatic vision was evaluated using the Farnsworth-panel D15 and the L''Anthony D15 tests of Vision Color Recorder software. Reading ability was measured using Radner-Vissum test. Results. Contrast sensitivity (with photopic and mesopic luminance with glare) differed significantly between patients with early and moderate visual field defects (p < 0.05). Reading ability scores and results of the chromatic vision tests did not differ significantly between the two groups. Significant and moderate Spearman correlations between visual field indexes and contrast sensitivity tests were detected. Conclusions. Contrast sensitivity was significantly worse in patients with moderate glaucoma compared to those with early-stage glaucoma. Evaluation of visual function in clinical practice provides important information to address a glaucoma patient''s vision complaints

Visual dysfunction and its correlation with retinal changes in patients with Parkinson’ s disease: an observational cross-sectional study

Objectives: To evaluate visual dysfunction and its correlation with structural changes in the retina in patients with Parkinson’s disease (PD). Methods: Patients with PD (n=37) and controls (n=37) were included in an observational cross- sectional study, and underwent visual acuity (VA), colour vision (using the Farnsworth and Lanthony desaturated D15 colour tests) and contrast sensitivity vision (CSV; using the Pelli-Robson chart and CSV 1000E test) evaluation to measure visual dysfunction. Structural measurements of the retinal nerve fibre layer (RNFL), and macular and ganglion cell layer (GCL) thicknesses, were obtained using spectral domain optical coherence tomography (SD-OCT). Comparison of obtained data, and correlation analysis between functional and structural results were performed. Results: VA (in all different contrast levels) and all CSV spatial frequencies were significantly worse in patients with PD than in controls. Colour vision was significantly affected based on the Lanthony colour test. Significant GCL loss was observed in the minimum GCL+inner plexiform layer. A clear tendency towards a reduction in several macular sectors (central, outer inferior, outer temporal and superior (inner and outer)) and in the temporal quadrant of the RNFL thickness was observed, although the difference was not significant. CSV was the functional parameter most strongly correlated with structural measurements in PD. Colour vision was associated with most GCL measurements. Macular thickness was strongly correlated with macular volume and functional parameters (r>0.70, p<0.05). Conclusions: Patients with PD had visual dysfunction that correlated with structural changes evaluated by SD-OCT. GCL measurements may be reliable indicators of visual impairment in patients with PD

Comparison of visual and optical quality of monofocal versus multifocal intraocular lenses

Objective: To compare visual quality in patients implanted with Tecnis ® monofocal (ZCB00) and multifocal (ZMB00) intraocular lenses taking into account their optical quality measured in vitro with an eye model. Methods: In total, 122 patients participated in this study: 44 implanted with monofocal and 78 with multifocal intraocular lenses. Measurements of visual acuity and contrast sensitivity were performed. The optical quality of the intraocular lenses was evaluated in three image planes (distance, intermediate and near) using an eye model on a test bench. The metric considered was the area under the curve of the modulation transfer function. Results: Optical quality at the far focus of the monofocal intraocular lens (area under the curve of the modulation transfer function = 66.97) was considerably better than that with the multifocal lens (area under the curve of the modulation transfer function = 32.54). However, no significant differences were observed between groups at the distance-corrected visual acuity. Distance-corrected near vision was better in the multifocal (0.15 ± 0.20 logMAR) than that in the monofocal group (0.43 ± 0.21 logMAR, p < 0.001), which correlated with the better optical quality at near reached by the multifocal intraocular lens (area under the curve of the modulation transfer function = 29.11) in comparison with the monofocal intraocular lens (area under the curve of the modulation transfer function = 5.0). In intermediate vision, visual acuity was 0.28 ± 0.16 logMAR (multifocal) and 0.36 ± 0.14 logMAR (monofocal) with p = 0.014, also in good agreement with the values measured in the optical quality (area under the curve of the modulation transfer function = 10.69 (multifocal) and 8.86 (monofocal)). The contrast sensitivity was similar in almost all frequencies. Pelli–Robson was slightly better in the monofocal (1.73) than in the multifocal group (1.64; p = 0.023). Conclusion: Patients implanted with multifocal ZMB00 achieved a distance visual acuity similar to those implanted with monofocal ZCB00, but showed significantly better intermediate and near visual acuity. A correlation was found between intraocular lenses’ optical quality and patients’ visual acuity. Contrast sensitivity was very similar between the multifocal and monofocal groups