Is corneal sensitivity sex dependent?

Purpose: To determine whether corneal sensitivity is different between the two genders. Methods: Corneal sensitivity of 130 normal volunteers, including 77 women and 53 men aged 20-35 years, with no history of previous ocular surgery was measured using the Cochet-Bonnet esthesiometer. Measurements were done on five corneal regions: central, nasal, inferior, temporal and superior. The findings were compared between men and women using the non-parametric Mann-Whitney U test. Results: Mean age of male subjects was 28.0 years and that of female participants was 26.8 years (P = 0.063). There was a significant difference in corneal sensitivity between men and women in the superior (P = 0.013), temporal (P = 0.020) and inferior (P = 0.046) regions. There was no significant difference in corneal sensitivity in the central (P = 0.862) and nasal (P = 0.273) regions. Conclusion: Except for the central and nasal regions, corneal sensitivity is significantly higher in men as compared to women. The reason for this difference is not yet evident. © 2015 Journal of Ophthalmic and Vision Research

Risk factors of regression and undercorrection in photorefractive keratectomy: A case-control study

�AIM: To determine risk factors of regression and undercorrection following photorefractive keratectomy (PRK) in myopia or myopic astigmatism. �METHODS: A case-control study was designed in which eyes with an indication for re-treatment (RT) were defined as cases; primary criteria for RT indication, as assessed at least 9mo postoperatively, included an uncorrected distance visual acuity (UDVA) of 20/30 or worse and a stable refraction for more than 3mo. Additional considerations included optical quality symptoms and significant higher order aberrations (HOAs). Controls were chosen from the same cohort of operated eyes which had complete post-operative follow up data beyond 9mo and did not need RT. The cohort included patients who had undergone PRK by the Tissue-Saving (TS) ablation profile of Technolas 217z100 excimer laser (Bausch & Lomb, Rochester, NY, USA). Mitomycin C had been used in all of the primary procedures. �RESULTS: We had 70 case eyes and 158 control eyes, and they were comparable in terms of age, sex and follow-up time (P values:0.58, 1.00 and 0.89, respectively). Pre-operative spherical equivalent of more than -5.00 diopter (D), intended optical zone (OZ) diameter of less than 6.00 mm and ocular fixation instability during laser ablation were associated with RT indications (all P values -5.00 D), smaller OZ (<6.00 mm) and unstable fixation during laser ablation of PRK for myopia and myopic astigmatism were found to be strong predictors of undercorrection and regression. © 2015 International Journal of Ophthalmology (c/o Editorial Office). All Rights Reserved

Corneal aberration changes after rigid gas permeable contact lens wear in keratokonic patients

Purpose To determine the short-term effect of rigid gas permeable (RGP) contact lenses on corneal aberrations in keratoconic patients. Method Sixteen keratoconic eyes with no history of RGP lens wear were included. They all had corneal aberrometry using Pentacam, and different aberration indices of the anterior and posterior surfaces of the cornea were measured before and 3 months after fitting RGP lenses. The effect of baseline parameters on these changes was tested in univariate and multiple models. Results Total aberrations and individual Zernike coefficients did not show statistically significant changes after using RGP lenses. Although not statistically significant, vertical coma decreased in the anterior (p = 0.073) and posterior surface (p = 0.095). Relationships that remained statistically significant in the multiple model were between baseline central corneal thickness and changes in total higher order aberrations and anterior 4th order astigmatism 0°, and between baseline 2nd order astigmatism 45° and its changes. Conclusion In this study, corneal aberrations remained unchanged 3 months after wearing RGP contact lens. Further studies with sufficient samples in different groups of keratoconus severity or baseline aberrations are needed to obtain more accurate results. © 2016 Iranian Society of Ophthalmolog

Synergistic Antibacterial Effects of Metallic Nanoparticle Combinations

© The Author(s) 2019.Metallic nanoparticles have unique antimicrobial properties that make them suitable for use within medical and pharmaceutical devices to prevent the spread of infection in healthcare. The use of nanoparticles in healthcare is on the increase with silver being used in many devices. However, not all metallic nanoparticles can target and kill all disease-causing bacteria. To overcome this, a combination of several different metallic nanoparticles were used in this study to compare effects of multiple metallic nanoparticles when in combination than when used singly, as single elemental nanoparticles (SENPs), against two common hospital acquired pathogens (Staphylococcus aureus and Pseudomonas. aeruginosa). Flow cytometry LIVE/DEAD assay was used to determine rates of cell death within a bacterial population when exposed to the nanoparticles. Results were analysed using linear models to compare effectiveness of three different metallic nanoparticles, tungsten carbide (WC), silver (Ag) and copper (Cu), in combination and separately. Results show that when the nanoparticles are placed in combination (NPCs), antimicrobial effects significantly increase than when compared with SENPs (P < 0.01). This study demonstrates that certain metallic nanoparticles can be used in combination to improve the antimicrobial efficiency in destroying morphologically distinct pathogens within the healthcare and pharmaceutical industry.Peer reviewe

Electroretinogram changes following sequential panretinal photocoagulation for proliferative diabetic retinopathy

Purpose: To evaluate changes in electroretinogram (ERG) response over the course of multiple sessions of panretinal photocoagulation (PRP) in patients with proliferative diabetic retinopathy (PRP). Methods: A prospective cohort study of 11 patients with PDR who required PRP was conducted. PRP was completed over three sessions. Each patient had five ERGs done: baseline, 1 week after each PRP session, and 6 weeks after the last session of PRP. Dark-adapted 0.01 ERG, Dark-adapted 3 ERG, Dark-adapted 10 ERG, Light-adapted 3 ERG, and Light-adapted 30 Hz flicker ERG were done. The mean change in a-and b-wave amplitudes as well as implicit times compared to baseline was analyzed. Results: A significant reduction in peak amplitudes of both a-and b-waves and delay in latencies were observed in all responses (p<0.05). The absolute amplitude reduction and delay in latency were higher for scotopic b-waves (p<0.05). The root mean square (RMS) of Dark-adapted 10.0 ERG (p<0.05) and total mean amplitude changes of a-and b-waves (p<0.001) were reduced after each laser session; however, the magnitude of change was not different between the first, second, or third sessions of PRP, and each session showed a similar deterioration rate of ERG parameters comparing to each other (p=0.4 for RMS and p=0.2 for total mean amplitude changes). In addition, the results indicated recovery of the amplitude and latency of ERG waves after 6 weeks from the final treatment (p<0.001) although not to baseline levels. Conclusion: ERG findings following PRP show reduced retinal function after each session which partially recovers by 6 weeks after the completion of therapy. Clinicians should be mindful of these changes when planning the treatment course for patients with PDR. © 2020 Khojasteh et al

The study of some trophic index in Anzali lagoon

Anzali wetland is one of the most important ecosystem in the southern Caspian Sea, acts as a special ecotone between different ecosystems; terrestrial, the Caspian Sea, brackish and fresh water environments. The hydro chemical and nutrients parameters were monthly studied in 10 locations of Anzali wetland for one year from May 2014. Trophic status index was calculated by different parameters including chlorophyll a, total phosphorus (TP), total nitrogen (TN) and transparency. Results showed that the annual average of total nitrogen, total phosphorus and dissolved oxygen were 1.023±0.523, 0.113± 0.105 and 8.71 ± 2.63 mgL^-1 respectively. While no significant difference was observed in total nitrogen (P>0.05), total phosphorus showed a significant difference (P<0.05) among locations. Chlorophyll a varied between 0.6 to 330 (average 47.4 ± 65.0) µgL^-1. EC varied between 254 and 14250 µm and had a significant difference among locations (p<0.05). The TN/TP was lower than 10 in Anzali wetland (except in western area) that show the limitation role of TP in eutrophication process. According to results while the western area and SiahKeshim are observed in eutrophic and super eutrophic status, the rest of regions are classified as hyper eutrophic status. Decrease of nutrient components from inlet rivers and to remove the aquatic plants in Anzali water bodies are recommended to control of eutrophication process in Anzali wetland

Bio-ecological study of river estuaries in Guilan province

The Caspian Sea with brackish water is known as typical environment due to geo position, precious biota and the largest land-enclosed drainage area in the world. Macrobenthos were performed the main group of the Caspian Sea fauna. While they use as environmental bio-assessment, they have not completely studied in the Caspian Sea especially in estuaries environments. In this survey were studied eighteen river estuaries in Guilan province off Caspian sea southwest including Asrara, Chelevand, Lemir, Havigh, Shirabad, Khotbesara, Lisar, Karganroud, Navroud, Nokandekeh, Sefidrud, Heshmatrud, Langerud, Polerud and Chabokrud. The macro-invertebrate sampling was conducted seasonally at eight stations during autumn 2008 to autumn 2009. The macrobenthos organisms were identified as possible level in genus or species. The Shannon Wiener diversity and the Hilsenhoff biotic indices were used for evaluation of environmental quality. In this study, 69 genus identified that belong to 36 families and 16 orders. The most presentation of genus belongs to Chironomidae family with twenty six genus while others families were included forty three genus. The most average of macro-invertebrate abundance belong to order of Diptera with 35 %, subsequently the abundance of Amphipoda and Bivalvia orders occupied the second rank with 8.2 %. Orders Polychaeta, Oligochaeta and Cumacea had a low abundance during the study, however the Polychaeta showed a high abundance in some seasons and stations (up to 25%). The Plecoptera was rarely observed in some stations with high abundance. The Stenogammarus genus had the normally distribution during study, while Chironomidae genera as Eukifferiella and Cricotopus were measured in the high abundance during autumn 2008 to spring 2009. While Streblospio and Limnodrilus had the high presentation during winter and spring 2009, Cerastoderma sp. showed a high percentage in spring and summer 2009. The result of Shannon Wiener index values showed a significantly difference among regions for most seasons. There was also observed significantly difference for diversity values among stations in different seasons. According to Hilsenhoff biotic index for water quality classification; the most stations had good quality in spring 2009, while they were slightly and moderately good condition in winter 2009. The water quality of the Caspian Sea stations was in good condition as compared with the rivers estuary stations

Quantitative assessment of biopllution caused by Mnemiopsis leidyi on ecological community structure in the southern part of the Caspian Sea

After the arrival of the invasive spexies (Mnemiopsis leidyi) in the ecosystem of Caspian Sea in 1999, It had notable impacts. In this study, we,re assessing impacts of quantitative M. leidyi as a biopllutant on zooplankton community in the southern part of the Caspian Sea during 2001-2010 period. It becomes clear that Abundance and Distribution Range (ADR) of M.leidyi during 2001-2009 was in class E(occurrence in high numbers in all localities) and in year 2010 was in class D(occurrence in moderate numbers in all localities). from 2001- 2009, ADR in Summer season was in class E, but in summer 2010, relatinve biomass of M.leidyi has decreased and ADR was evaluated as D. During the fall seasons of 2001 -2010, only in fall of 2003 and 2010, the ADR was C(occurrence in low numbers in all localities) and D respectively and in other years, the ADR was in class E. In winter season relative biomass of M.leidyi decreased and only in winter of 2001 relative biomass was high and the highest ADR (class E). In winter 2003 and 2004, ADR was in class D. The biomass of M.leidyi was found to be zero in winter 2008. From winter of 2009-2010,ADR, were assessed B and A respectively. In the spring, ADR was evaluated A and D. Considering the obtained results, the yesr 2001, which the relative niomass was more than 90 percent, could be considered as the expantion phase and the following years (2002-2010) with regard to decrease of relative biomass as the adjustment phase. With regards to the loss of the keystone species (Eurytemora sP.) and some other native species, our evalution showed that the impact of M.leidyi on structure of zooplankton community was assessed as massive (C4).During summer and fall seasons that biomass of M.leidyi was higher than 50%, only A.tonsa exist, but during spring and winter seasons that biomass of M.leidyi was decreased and more species have a chance to exist

Studying the impacts of the rainbow trout farms effluents on Sabzkooh River in Charmahal-O-Bakhtiari Province

Sabzkooh in Ardal and Gandoman region in Charmahal province with annual production of 1300 metric tons of rainbow trout, is one of the most important rivers in the province. The effects of fish farms effluent on the river water quality and the possibilities to develop or limit the existing ones were studied. Flora and fauna of the river including Phyto and zooplankton, macroinvertebrates and fishes were sampled and studied. Moreover some key physico-chemical water quality parameters, concentrations of stable pollutants (heavy metals: Zn, Cu, Fe, Pb, Cd and agricultural poisons (herbicides or pesticides: DDT, Lindane, Alderine and indosulfate) and Coliform contamination were also measured. All phytoplankton genus were of tow taxa, Cianophyta and Chrysophyta and zooplankton fauna belonged to Rotatoria, Protozoa and meroplanktonic chirinomids and nematodes. Four fish species from 3 families were identified of which rainbow trout had the highest relative frequency (94.6%).All the measured heavy metals including Zn, Cu, Fe, Pb, Cd and the agricultural poisons concentrations such as DDT, Lindane, Alderine and indosulfate were lower than the hazardous level suggested for the surface waters. According to the benthic macroinvertebrates populations study, stations at downstream (no. 6 and 7) which received the Chartakhteh and Rudarud farms effluent had least EPT richness and the hilsenhof family level biotic index at this locations was greater than 5.25, classifying them as having organic pollution. Even though measured key physico-chemical parameters such as nutrients (N and P compounds and BOD5) in the receiving stations and effluent water never exceed the maximum permitted range but in downstream stations these factors were very close to the range. One way analyze of variance (P 95%) for TN, TP, No_2, NH_4, BOD_5, pH, PO_4 and Ec revealed no significant differences between stations before and just after receiving the effluents, however these parameters in the effluents themselves significantly differ from upstream stations 1,2 and 3 proving relatively lower organic pollution and the potential for constructing new farms or expanding the existed ones in upstream region from Chartagh to Dehnoo. At downstream from Dehnoo to Rudarud and lower parts, dense trout farm effluents in addition with point and non point pollution (municipal, agricultural and other coming run off from the catchments area) had remarkable effects on the river water quality and as a result no farm construction or expansion is recommended. To avoid or reduce the existing farms effects on the river system there should be certainly some remediation actions carried out. Constructing sedimentation ponds before releasing the effluents, obeying the rule of water extracting, preventing fish escape, increasing feeding efficiency and controlling the lateral inlets from catchments area which are potentially pollutant, should be considered to improve the situation and prevent further environmental problems caused by fish farms effluent in these area

Limnological survey of Anzali Wetland data during 1990-2003 by use of GIS system

Anzali wetland at south west of Caspian located along of North West and southeast and with its unique feature were add on the Ramsar convention list in 1975. There were recorded a high rich of fauna and flora including 276 plant species, 23 reptiles and amphibians, 60 fishes, 26 mammals and 195 birds. Anzali wetland were encountered with numerous disorder with the eutrophication and the early dismissing. The first studies on Anzali wetland started by many international institutions in 1964. In this study the data of biotic and abiotic factors in Anzali wetland analyzed which belongs to different sites (15 to 38 stations) during 1991 to 2000 and were sampled seasonally or monthly in different years. The results showed the increasing trend of phytoplankton abundance from 7.9 to 66 million C./l. and the western part had the most abundant. The Cyanophyta had the most development than other 7 phylum observed in the area. In Anzali wetland identified 143 phytoplankton genus that 9 genus dominated in more than 80 % replicates and 7 genus had the abundance of more than 5 million cell/l. The Zooplankton abundant increased from 580 to 2200 ind./l. The Rotatoria had the most abundant followed by Copepoda. There was identified 104 zooplankton genus that 5 genus were dominated in more than 80 % replicates and 11 genus had the abundance of more than 30 ind./L. The chlorophyll a varied from 8.8 to 50.2 μg/l. and had a increasing trend after 1996, meanwhile it was measured higher than 25 μg/l in most of the stations. The results of benthic study showed that the Chironomidae and Tubificidae were observed more than other organisms which comprised 12.2 to 23.5% of total biomass of benthic organisms in studied period. The range of biomass was 1.1 to 7.8 g/m2. The ichthyologic survey showed presence of 60 species that 11 species were exotic. 28 species belong to freshwater, 17 species were anadromous and 8 species were resident in estuary. The highest and lowest fish catch were 640 and 288 ton in 1994 and 1999 respectively and it was about 500 ton at the end of period. The hydrochemical factors had the various fluctuation so that the nutrients parameters had a significant difference over studied period. Total nitrogen was varied from 0.78 to 1.41 mg/l and total phosphorus varied from 0.05 to 0.1 μg/l.. The oxygen dissolved amount was from 4.6 to 8.7. EC was between 3 to 5 ms/cm during September and October that indicated of Caspian water projection. According to geographic position of station, all biotic and abiotic data, were arranged. The data bank is used by Idrisi software to produce of necessary maps. Analysis of data showed that there must be a responsible department with a vast authority. Conservation and eutrophication prevention of Anzali wetland connect to special attention to catchment area and landuse management of the wetland. Also there is an urgent need for well-developed technologies and managements to reduce the organic pollution and its environmental impacts on the Anzali Lagoon