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Stand and leaf scale responses of loess grassland swards to elevated air CO 2 concentration had been investigated in a mini FACE system during 1998–2000. The study concentrated on biomass, leaf area index (LAI) and vegetation surface temperature (stand scale) and on diurnal carbohydrate pattern and gas-exchange responses (leaf scale). Leaf net CO 2 uptake under prolonged exposure to elevated CO 2 showed an upward response in the dicotyledonous and a downward one in the monocotyledonous species. Dawn and evening carbohydrate levels in leaves suggested growth stimulation of the dicot under elevated CO 2 and the opposite for the grass species and indicated sink limitation as a major factor determining photosynthetic acclimation at the species level. The smaller LAI as well as the insignificant biomass response to elevated air CO 2 was a compounded response by multi-species stands. Under mild water shortage, elevated air CO 2 concentration partly alleviated the drought effect shown by the higher relative growth rate of LAI. Canopy surface temperatures of the vegetation in the CO 2 enriched rings were higher than those in the ambient rings suggesting that decreased leaf conductance and transpiration were responsible for the temperature difference between the treatments. Increased canopy surface temperature under elevated air CO 2 concentration will probably lead to increased sensible heat flux and therefore enhanced convection at larger spatial scales.
Abstract
Coronavirus-19 infection caused a mysterious pandemic worldwide. Some people experienced flu-like symptoms, while others have died due to pulmonary complications. Besides droplet spread, other routes of infection started to be suspected, such as through eye contact. During the first phase of the pandemic, pulmonary symptoms were in focus, later other signs and symptoms were also published. Eyelid, anterior and posterior segment symptoms, neuro-ophthalmic complications, and orbital problems related to COVID-19 infections are discussed in this article. It is important to detect the serious signs and symptoms to prevent late, sight threatening complications of COVID-19 infection.
History of cataract surgery from ancient times to today
Honorary Lecture at the 13th Conference of the Hungarian Medical Association of America – Hungary Chapter (HMAA-HC) at 30–31 August 2019, in Balatonfüred, Hungary
Abstract
Cataract surgery is the most frequently performed ophthalmic surgery worldwide. This year approximately 32 million surgeries will be performed. The journey to modern, quick, and safe cataract surgery has been quite long. This review covers topics from ancient couching to the most modern phacoemulsification and femtosecond laser-assisted cataract surgery. The gain in quality of life is the largest with cataract surgery compared to other implant surgeries (e.g. knee, hip replacement, etc.). Ophthalmology has made huge advancements in recent decades. New microsurgical tools and diagnostic equipment have been developed, together with new surgical methods and foldable intraocular lenses, made from biocompatible material. From monofocal lenses, through aspheric, toric, and multifocal lenses, to multifocal toric lenses, today almost all kinds of refractive error can be compensated, including presbyopia. Teamwork, precise preoperative assessment, and fine surgical technique should also be emphasized in order to achieve the best and most predictable postoperative results for both patient and surgeon.
Abstract
Preeclampsia is a severe, sometimes life-threatening complication of pathological pregnancies. The incidence of neonatal morbidity and mortality is usually increased. Besides general maternal symptoms like hemolysis, low platelet number, elevated liver enzyme level, proteinuria, cardiovascular problems, neurological and cerebral complications, serious ophthalmic symptoms might occur. These include focal or generalized narrowing of the arterioles, flame-shaped retinal haemorrhages, and cotton-wool spots. Rarely, disc swelling, exudative retinal detachment, cystoid macular edema, bilateral occipital lobe infarction, or cortical blindness might occur. In this article, I review the retinal and macular changes, retinal detachment, and the cause of blindness. Optical coherence tomography (OCT) allows ophthalmologists to diagnose early and late changes in choroid vasculature and circulation, and consequent retinal morphological changes. Spectral-domain OCT and enhanced depth imaging provide important insight and possible prognosis for the course of the disease. After termination of the pathological pregnancy, vision returns to normal in most cases; unfortunately, there are some exceptions.
The effects of UV-C radiation on the germination rate and fungal contamination of tall fescue seeds were investigated. Samples from the same seed lot were irradiated in two different ways in two consecutive years. The seeds were irradiated with a Hg vapour lamp using different doses. In the first trial one side of the seeds was irradiated, while in the second trial a mirror was used to irradiate the whole seed surface. The results showed that various doses of UV-C irradiation had an effect on the germination rate, but there were no significant differences in germination percentage between the treatments. Differences in fungal contamination rates were observed when the seeds were irradiated on all sides. The presence of 21 fungal genera was identified on the seeds, the saprotrophic fungi Alternaria, Rhizopus and Penicillium being dominant.
The aim of the present work was to study the soil seed bank of the semiarid sandy grassland community using the nested sampling procedure. The samples consisted of six concentric cores with diameters ranging from 5 to 22 cm and surface area ratio of the outermost to the innermost ring of 19. Investigations were directed to establish the minimum core diameter to find the dominant and less frequent species in the seed bank and also to have an insight on distribution patterns of species. The smallest core (diameter: 5 cm) employed in 20 repetitions was adequate to find the dominant species in the seed bank, while increasing the sample area to 19 times resulted in doubling the number of species found. The seeds of the dominant species had clustered distribution even at the smallest applied sample scale, while patterns of seed clumps followed different (uniform, contagious, random) distributions.
The survey was carried out on the seed bank of several patches of an open, semiarid sandy grassland (Festucetum vaginatae Rapaics ex Soó 1929 (Borhidi 1996)). We chose four, approximately 20 m × 20 m large, adjacent patches, different in their species composition and total cover. Soil samples were taken in early spring and at the end of summer, in two consecutive years. We determined the seed bank of the samples with the seedling emergence method. The fact that we found the seeds of only two species that were not present in the vegetation indicates the isolated and without artificial disturbed state of the grassland. The vegetation and the seed bank of the patches showed a low degree of similarity in the same period, while the composition of the spring aspect reflected clearly in the seed bank of late summer in all four patches. Results showed that mosaic-like appearance is not only characteristic of the vegetation, but also the seed bank of the soil. Differentiation of the seed bank manifested mostly after the period of seed-fall, at the end of summer, while in early spring it was less expressed. On the basis of the differentiation of the seed bank we can conclude that not the dispersion of seeds, but natural vicinity of mother plants was decisive in forming the spatial variation of the seed bank.
Abstract
Ageing is a common problem in modern societies. Due to sophisticated new methods in medicine, the average life expectancy significantly increased in recent years. 70 is the new 50. The new principles of food intake and processing, more exercise, and less smoking contributed to a health benefits and a longer life span of human kind. Nevertheless, there are the special problems of ageing. Numerous dysfunctions of the body may arise affecting a broad range of organs and the musculoskeletal system. The eye can also be severely affected by ageing. Vision gained more importance recently especially during the COVID-19 pandemic. Elderly people who never used computers before, had to learn computer technology in order to communicate with their family and to accomplish their everyday tasks or pay their bills. Therefore, good near vision has become crucial for elderly people. In this review article the most common ageing problems of the eye, therapies and pathophysiology of ageing processes will be reviewed and discussed. There are physiological problems of ageing and there are ocular pathologies which can be treated efficiently in time to preserve near and far visual acuity.
