79 research outputs found
Five generations of intraocular lens power calculation formulas: A review
Background: The effectiveness of cataract surgery depends on preoperative biometric data, including the axial length (AL), keratometric value (K), anterior chamber depth (ACD), and the accuracy of the intraocular lens power (IOLp) calculation. Five generations of IOLp calculation formulas have been developed. This review summarizes these formulas and focuses on the characteristics, advantages, and disadvantages of each. Moreover, it compares the results of several formulas used in patients with specific characteristics.
Methods: The authors searched PubMed and Google Scholar, using keyword combinations including IOLp, formulas, AL, ACD, K, and diopters (D). Two hundred recent articles that referred to IOLp calculation formulas and their effectiveness when used preoperatively in cataract surgery were retrieved and analyzed.
Results: Each generation has advantages and disadvantages for individual patients, and the selection of the most appropriate IOL differs due to patients’ different ALs. The shorter or longer the eye is, the less accurate some formulas become. Formulas such as SRK-T, Holladay, SRK-II, Hoffer, and Binkhorst II seem to have comparable efficacy. However, studies have indicated that Hoffer is superior for short eyes. In contrast, SRK/T appears to be slightly more superior for long eyes. The fifth-generation formulas also appear to be very promising.
Conclusions: Based on the available literature, there is no gold standard as yet that can be used for all patients. Instead, each patient should be managed individually depending on their particular eye characteristics
Radiation treatment methods in uveal melanoma
Background: The most frequent primary ocular malignancy in the western world is the uveal melanoma. While it mainly affects Caucasians, it is extremely uncommon among non-Caucasians. Continuous improvement in therapies for local treatment has allowed sparing of the eye, although this approach apparently does not improve survival. The present review aimed to explain different radiotherapy (RT) methods and compare the pros and cons of each method, along with the main complications that may be encountered in the treatment of uveal melanoma.
Methods: Relevant papers published between September 2009 and January 2021 were retrieved, reviewed, and screened. Four databases, including PubMed, MEDLINE, Google Scholar, and GeneCards, were searched for this purpose.
Results: Forty-one relevant articles were identified. Based on the selected papers, we highlighted the advantages and disadvantages of the different RT methods that have allowed sparing of the eye, even though they have not, as yet, improved survival. We listed a detailed comparison between therapies that allow an educated choice among the different available RT methods.
Conclusion: The choice of uveal melanoma management is determined by the location of the tumor and volume of the extraocular extent. At present, there is no gold standard for the management of all ocular melanomas, and each case should be approached individually. Therefore, classification is a valuable prognostic tool. Many cases in cT3-4 classification categories are treated by primary enucleation and conservative treatment follow-up, while in cT2 and most cT1 classifications (i.e., 3.1–6.0-mm tumor thickness), several forms of RT are used
Mortality and Effect on Growth of Artemia franciscana Exposed to Two Common Organic Pollutants
Acute toxicity and inhibition on growth of Artemia franciscana nauplii (Instar I-II) after exposure to the reference toxicants bisphenol a (BPA) and sodium dodecyl sulfate (SDS) were studied. LC50 values were calculated and differences in body growth were recorded after 24, 48, and 72 h of exposure to the toxicants. The results indicated that BPA had lower toxicity than SDS. Development of the nauplii was clearly influenced by duration of exposure. Growth inhibition was detected for both toxicants. Abnormal growth of the central eye of several Artemia nauplii after 72 h of exposure to BPA was also detected. Our results indicate that growth inhibition could be used as a valid endpoint for toxicity studies
Leaching behaviour of pendimethalin causes toxicity towards different cultivars of Brassica juncea and Brassica campestris in sandy loam soil
An experiment was conducted at the farm of Zonal Adaptive Research Station, Uttar Banga Krishi Viswavidhyalaya, Pundibari, Cooch Behar, West Bengal to evaluate the effect of pendimethalin on the yield, weed density and phytotoxicity in different varieties of rai (Brassica juncea) and yellow sarson (B. campestris var. yellow sarson) under higher soil moisture regime in Terai region of West Bengal. Pre-emergence application of pendimethalin at higher dose i.e. 1.0 kg/ha recorded higher plant mortality (30.92%) due to the presence of higher concentration of pendimethalin residue (0.292 µg/g) till the tenth day of crop age and consequently had the reduced yield (12.59 q/ha) than the dose of 0.7 kg/ha (13.33 q/ha) where plant mortality was only 12.62% due to comparatively lower level of pendimethalin residue (0.192 µg/g). Although the application of pendimethalin at the rate of 1.0 kg/ha was able to control weed more efficiently (18.96/m2) than the dose of 0.7 kg/ha (30.41/m2) and subsequent lower doses. The herbicide leached down to the root zone resulting in phytotoxicity towards crop. Yellow sarson group (Brassica campestris) showed more susceptibility than rai (Brassica juncea) group against pendimethalin application at higher doses
Yield and silymarin content in milk thistle (Silybum marianum (L.) Gaertn.) fruits affected by the nitrogen fertilizers
Milk thistle (Silybum marianum (L.) Gaertn.) is a common weed that has been introduced as a medicinal plant for silymarin production. This renders it important to optimize cultivation techniques, including fertilization. In the present study, a two-year field experiment was conducted to evaluate the influence of conventional and stabilized nitrogen fertilizers on plant growth, fruit yield, and fruit quality. The experiment was conducted in a randomized complete block design with five fertilization treatments (control, conventional nitrogen fertilizer applied at 75 kg/ha and 125 kg/ha, and stabilized nitrogen fertilizer applied at 75 kg/ha and 125 kg/ha. Nitrogen fertilization had a significant effect on vegetative and yield parameters. Specifically, the application of nitrogen fertilizers positively influenced rosette diameter, height, aboveground dry biomass, total chlorophyll content, number of capitula per plant, number of fruits per central capitulum, and fruit yield. In particular, in most traits, the usage of high nitrogen levels of the two types of fertilizer had the most pronounced impact. The application of the stabilized fertilizer at a rate of 125 kg N/ha induced an increase in fruit yield of up to 29.6 %. Nitrogen fertilization had no impact on the accumulation of oil and silymarin in the fruits, although some effects on oil and silymarin yield were noted. In general, the application of nitrogen fertilizers had no effect on the antioxidant activity or total phenolic content of the fruit extracts. Finally, climatic conditions affected the growth and productivity of milk thistle, as fruit yield was favoured by wet conditions. © 2021 Elsevier B.V
Persistence of pendimethalin in cotton fields under sprinkler or drip irrigation in central Greece
The dissipation of pendimethalin was investigated in soils of cotton fields in Thessaly, central Greece, for a period of two years. The fields were irrigated either with sprinkler or with sprinkler for the first two irrigations plus drip for the rest of the experimental period. Pendimethalin was applied at rates of 1.1, 1.32, and 0.96 kg a.i./ha in a clay loam soil at Rizomylos, a clay soil at Kypseli, and a sandy clay loam soil at Karditsa, respectively. Residues were determined with capillary GC-NPD after ethyl acetate extraction. Recovery of pendimethalin from spiked soils was 82-101% with a repeatability of 2-7%, and the limit of quantification was near 0.04 mg/kg. At 150 days after application (DAA) pendimethalin residues found in the soils were 10-18% of the initial measured concentrations. For the drip-irrigated fields, dissipation of pendimethalin varied within the field between the non-irrigated and the irrigated soil regions, indicating a more rapid loss in the irrigated part of the soil. Residues in the wet region (along the drip irrigation line) at 150 DAA were about 75 and 60% of those measured in the dry region (off the irrigation line) of the soil at the Kypseli field for the 1996 and 1997 season, respectively. At the Rizomylos field the corresponding percentage was about 70%, for the 1997 season. The half-life, calculated from the first-order kinetics dissipation equation, was estimated at between 43 and 62 days. No leaching of pendimethalin was observed below 10 cm during the experimental period of 230 days under cotton growing conditions in Thessalian fields
Behaviour of fenitrothion residues in leaves and soil of vineyard after treatment with microencapsulate and emulsified formulations
The rate of decline of fenitrothion residues was investigated in leaves and soil of vineyard over 2 months after treatment with two different kinds of commercial formulations: emulsifiable concentrate (EC) and microencapsulate (ME). Fenitrothion residues were determined with GCNPD after acetone extraction of soil and leaves. The measured initial deposits in soil and leaves varied between 2.6 and 3.8 mgkg-(1) and between 89 and 101 mg kg-(1), respectively. Fenitrothion residues in soil dropped at 0.1-0.2 mg kg-(1) after 60 days following application with EC formulation showing a more rapid decline than the ME. Fenitrothion residues in leaves from ME formulation treatment showed a longer persistence and lower decline rate than those from EC formulation. During the experimental period, fenitrothion remaining in leaves from ME application was 10 times more than from the EC one. Mathematically defined decline curves were established by determining optimal relationships between fenitrothion residues and time. The RF1st-order and RF1.5th-order equation achieved the best adjustment to the experimental data of fenitrothion dissipation on leaves for the ME and EC formulation, respectively, giving fenitrothion half-lives of about 2-3 days for ME and < 1 day for EC formulation. In vineyard soil, the best adjustment to the experimental data for ME and EC formulation was achieved by the 1st-order and 1.5th-order equations, respectively, giving fenitrothion half-lives in soil of about 17-21 days for ME and 5 days for EC formulation
Water quality assessment by ecotoxicological and chemical methods in Magnesia, Greece
The fresh- and seawater quality in Magnesia, Greece, was evaluated in this work, using a combination of bioassays and chemical analytical techniques. The crustacean and the invertebrate saline water shrimp Artemia franciscana were used as test species for monitoring the quality of fresh- and seawater samples respectively. Furthermore, chemical analysis was performed in the samples, for the assessment of pollutants loading. In general, both fresh- and seawater toxicity was low, indicating the good environmental conditions in the area. However, two seawater samples and one freshwater sample, presented high toxicity values, which is in agreement with the chemical measurements. © 2004 Kluwer Academic Publishers
- …