Fifteen years follow-up of photorefractive keratectomy up to 10 D of myopia: outcomes and analysis of the refractive regression

PURPOSE: To evaluate outcomes of photorefractive keratectomy up to -10.00 D of myopia and -4.50 of astigmatism and to develop a predictive model for the refractive changes in the long term. SETTING: Vissum Corporation and Miguel Hernandez University (Alicante, Spain). DESIGN: Retrospective-prospective observational series of cases. METHODS: This study included 33 eyes of 33 patients aged 46.79±7.04 years (range 40-57) operated with the VISX 20/20 excimer laser with optical zones of 6 mm. No mitomycin C was used in any of these cases. The minimum follow-up was 15 years. The main outcome measures were: uncorrected and corrected distance visual acuity, manifest refraction and corneal topography. Linear regression models were developed from the observed refractive changes over time. RESULTS: Safety and efficacy indexes at 15 years were 1.18 and 0.83, respectively. No statistically significant differences were detected for any keratometric variable during the follow-up (p≥0.103). 15 years after the surgery 54.55% of the eyes were within ±1.00 D of spherical equivalent and 84.85% within ±2.00 D. The uncorrected distance visual acuity at 15 years was 20/25 or better in 60.6% of the eyes and 20/40 or better in 72.73% of the eyes. The correlation between the attempted and the achieved refractions was r=0.948 (p<0.001) at 1 year, and r=0.821 (p<0.001) at 15 years. No corneal ectasia was detected in any case during the follow-up. CONCLUSIONS: Photorefractive keratectomy is a safe refractive procedure in the long term within the range of myopia currently considered suitable for its use, although its efficacy decreases with time, especially, in high myopia. The model developed predicts a myopic regression of 2.00 D at 15 years for an ablation depth of 130 µm

Analysis of the pathogenic factors and management of dry eye in ocular surface disorders

The tear film represents the interface between the eye and the environment. The alteration of the delicate balance that regulates the secretion and distribution of the tear film determines the dry eye (DE) syndrome. Despite having a multifactorial origin, the main risk factors are female gender and advanced age. Likewise, morphological changes in several glands and in the chemical composition of their secretions, such as proteins, mucins, lipidics, aqueous tears, and salinity, are highly relevant factors that maintain a steady ocular surface. Another key factor of recurrence and onset of the disease is the presence of local and/or systemic inflammation that involves the ocular surface. DE syndrome is one of the most commonly encountered diseases in clinical practice, and many other causes related to daily life and the increase in average life expectancy will contribute to its onset. This review will consider the disorders of the ocular surface that give rise to such a widespread pathology. At the end, the most recent therapeutic options for the management of DE will be briefly discussed according to the specific underlying pathology

Investigating the Impacts of Chinese Investments on the Global Competitiveness of Sub-Saharan Countries

The main objective of this study is to shed light on the effects of Chinese investments on the global competitiveness of Sub-Saharan Africa, specifically Chad, Ethiopia, and Ghana. The study employs a qualitative technique based on depth semi-structured interviews. In the in-depth interviews with field professionals and experts, four questions were asked to one participant from each country. The depth interviews show that Ghana and Ethiopia have the most competitive potential respectively. On the other hand, Chad has no chance of competing due to limited resources. While Chad is characterized by poor governance and limited economic freedom, Ghana and Ethiopia have relatively a large capacity to attract foreign investment. China, as a strong competitor, uses various strategies to beat local rivals in Chad, Ethiopia, and Ghana. In this regard, it offers a wide range of products of average quality at affordable prices to customers in Chad and Ethiopia, while benefiting from large-scale production, economies of scale, and tax breaks in Ghana. With this, local investors are unable to compete with China, which negatively impact the local markets to flourish, especially in the long run.

Alcance de los estudios sobre la pesca deportiva de los istiophoridae en Venezuela

On effectue l'analyse historique (1961-89) de la CPUE des poissons porte-épée capturés par la pêche sportive dans le principal port de plaisance du pays (Playa Grande Yatching Club). Bien qu'il existe une variabilité interannuelle accusée de la production, on peut observer que l'indice d'abondance du Makaire blanc (#Tetrapturus albidus) a baissé de façon continue ces dernières années, presqu'à son plus faible niveau historique. En ce qui concerne le Makaire bleu (#Makaira nigricans), la hausse de la CPUE, qui avait commencé au début des années quatre-vingt, s'est interrompue, et montrait déjà ces dernières années une tendance décroissante. Bien qu'encore faible, la CPUE du voilier (#Istiophorus albicans$) s'est stabilisée dans le courant de la décennie en cours. Exception faite de cette dernière espèce, on n'a pas observé d'individus sexuellement matures dans les échantillons. Chez les deux espèces de Makaires, les femelles atteignent une taille supérieure à celle des mâles, contrairement au voilier chez lequel il ne semble pas exister de différentiation sexuelle à cet égar

Removal of ethylbenzene and n-hexane from air streams by adsorption processes with activated carbon

Mestrado de dupla diplomação com a Université Libre de TunisThe development of chemical engineering process technologies in recent years has led to an increase in the quantities of volatile organic compounds (VOCs) released into the atmosphere. Some of these VOCs such as ethylbenzene and n-hexane, in addition to being polluting, are found to be harmful to human health. Multiple techniques have been developed for the capture of these VOCs in ambient air. Adsorption processes are recognized as being very competitive for the removal of VOCs regarding the efficiency and the costs of its application. In this work, the adsorption equilibria of ethylbenzene and n-hexane in a commercial activated carbon (Norit RB4) was studied at the temperatures of 398 K, 423 K and 448 K and pressures between 0.01 up to 0.1 bar using gas chromatography. At the temperature of 398 K and partial pressure of 0.1 bar the sorption uptake capacity of ethylbenzene is around 2.34 mol.kg-1, with a heat of adsorption in the range of 50.0 ~ 59.5 kJ.mol-1. For similar conditions the n-hexane sorption uptake is smaller being around 1.61 mol.kg-1 with a heat of adsorption in the range of 52.5 ~ 59.2 kJ.mol-1. The experimental adsorption equilibrium data was modelled with the Langmuir, Freundlich, Sips, Toth and Redlich-Peterson adsorption isotherms. It is shown that the best isotherm model that fits the experimental data is given by the Toth isotherm for the ethylbenzene, while the Freundlich isotherm is best suited for n-hexane.Le développement des technologies de procédés de génie chimique au cours des dernières années a entraîné une augmentation des quantités de composés organiques volatils (COV) libérées dans l’atmosphère. Certains de ces COV tels que l’éthylbenzène et le n-hexane, en plus d’être polluants, se révèlent nocifs pour la santé humaine. De multiples techniques ont été développées pour la capture de ces COV dans l’air ambiant. Les procédés d’adsorption sont reconnus comme étant très compétitifs pour l’élimination des COV en ce qui concerne l’efficacité et les coûts de leur application. Dans ce travail, les équilibres d’adsorption de l’éthylbenzène et du n-hexane dans un charbon actif commercial (Norit RB4) ont été étudiés à des températures de 398 K, 423 K et 448 K et à des pressions allant jusqu’à 0,1 bar à l’aide d’une technique de chromatographie en phase gazeuse. À la température de 398 K et à la pression partielle de 0,1 bar, la capacité d’absorption d’adsorption de l’éthylbenzène est d’environ 2,34 mol.kg-1, avec une chaleur isostérique d’adsorption comprise entre 50,0 et 59,5 kJ.mol-1. Pour des conditions similaires, l’absorption de la sorption du n-hexane est plus faible étant d’environ 1,61 mol.kg-1 avec une chaleur isostérique comprise entre 52,5 et 59,2 kJ.mol-1. Les données expérimentales d’équilibre d’adsorption ont été modélisées avec les isothermes d’adsorption de Langmuir, Freundlich, Sips, Toth et Redlich-Peterson. Il est démontré que le meilleur modèle isotherme qui correspond aux données expérimentales est donné par l’isotherme de Toth pour l’éthylbenzène, tandis que l’isotherme de Freundlich est la mieux adaptée au n-hexane

Gendered Violence, HIV Acquisition, and Clinical/Behavioral Research

HIV incidence and prevalence rates for US women continue to increase, especially among Black and Latina women. In addition, the link between violence and HIV acquisition has been well documented. However, the interaction between violence, HIV risk, and HIV acquisition remains an under-addressed issue in current clinical and behavioral HIV research designs. Because violence against women plays an important role in HIV acquisition and transmission, it is imperative for clinical research to address violence in trial design and implementation. In this article, we discuss the prevalence of violence in women’s lives; the role violence plays in HIV acquisition; and the absence of violence in clinical research designs. We conclude with recommendations for integrating concerns about HIV and violence against women into sponsor- and investigator-driven HIV research priorities and clinical trial design