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Abstract
Purpose
The aim of the study was to analyse the use of digital devices among children.
Materials/Methods
A specially designed questionnaire was distributed to 249 schoolchildren to assess their use of digital devices both in school and outside school. The questionnaire was used before the start of the COVID-19 pandemic. The children were asked about the extent of their use of digital devices, as well as about ophthalmic and general health complaints. Their responses were assessed statistically.
Results
Regarding age distribution, 145 children were between seven and 10 years old when they started to use digital devices. Most of the children used a digital device for between one and two hours a day. The majority preferred using smartphones. The second most popular devices were laptops and tablets, and the third most popular was the desktop computer. Fifty-six children wore glasses, 14 to correct hyperopia and 42 to correct myopia. 97 children spent between one and two hours a day outdoors; 99 children spent more than two hours outdoors; and 51 spent less than one hour outdoors. 71 children reported eye problems; 48 reported other general health problems (back and neck pain); and 43 mentioned blurred vision while using a digital device.
Conclusions
The use of digital devices can be regarded as general among schoolchildren, and most children use a digital device for longer than the recommended time. Excessive use of digital devices may contribute to an increase in the prevalence of myopia and other general eye and back problems.
The emergence of large fortifications at the beginning of Early Iron Age reflects a change in settlements system. The current paper studies settlement sites along with metal finds, graves and graveyards from Late Bronze Age cultures to Early Iron Age/Hallstatt period in the Transylvanian Plateau.Our aim is to investigate the transformations and the dynamics of the settlements through cartographic documents and data relating to the landscape around the sites (using satellite images, aerial photographs and geophysical measurements) stored in a geographic information system.Modeling the territories of central Transylvanian prehistoric communities provides information about the division of space and possible land use strategies. The research is also based on the existing macro-regional palaeo-environmental data of Central North-Western Romania.We can state that the Late Bronze Age and Early Iron Age chiefdoms form peer polities controlling small territories along single or more valleys. Our approach represents the actual stage of research of the subject; the future field researches will bring new concluding evidence in this matter.
The carbon balance of the sandy pasture (Bugac) and the mountain meadow (Mátra) varied between −171 and 96 gC m−2 year−1, and −194 and 14 gC m−2 year−1, respectively, during the study period (2003–2009). Large part of interannual variability of net ecosystem exchange (NEE) was explained by the variation of the annual sum of precipitation in the sandy grassland ecosystem, while this relationship was weaker in the case of the mountain meadow on heavy clay soil. These different responses are largely explained by soil texture characteristics leading to differences in soil water contents available to plants at the two grasslands. The grassland on heavy clay soil was more sensitive to temporal distribution of rainfall for the same reason. The mountain meadow therefore seems to be more vulnerable to droughts, while the sandy grassland is better adapted to water shortage. The precipitation threshold (annual sum), below which the grassland turns into source of carbon dioxide on annual basis, is only 50–80 mm higher than the 10 years average precipitation sum. In extremely dry years (2003, 2007 and 2009), even the sandy grassland ecosystem was not stable enough to maintain its sink character.
In vitro shoot multiplication of Telekia speciosa (Schreb.) Baumg. was tested on media containing benzyladenine, benzyladenine riboside, kinetin, zeatin, meta-topolin or 2-isopentenyladenine in different concentrations. We observed the proliferation rate, the length of shoots, rate of callus formation, and the presence of the hyperhydricity. The highest proliferation rate (13.17) was obtained on medium supplemented with 5.0 μM benzyladenine, however, the leaves were hyperhydrated at this concentration of benzyladenine, therefore for shoot multiplication lower (1.0 μM BA) concentration of benzyladenine is suggested. The longest shoots were achieved using 1.0 μM 2-iP. At this treatment 100% rooting was found, therefore the stage of rooting is omissible using 1.0 μM 2-iP during the multiplication. This in vitro propagation protocol should be useful for conservation as well as mass propagation of this plant species.
Abstract
Radioisotope induced X-ray fluorescence analysis is a rather simple and convenient method for investigating ashed plant material. In order to reduce matrix effects, thin samples (2 mg/cm2) are analyzed to obtain a reasonable compromise between maximum sensitivity and the lowest possible absorption effects. Concentrations are determined by standard addition method. A precision of 6–8% can be achieved. As an application, analytical results are given for whole grains of several sorts of wheat.
Although angiogenesis is considered to be indispensable for continuous tumour growth, only very few studies have been published performing microvessel quantification during tumour progression. We mea- sured the tumour vascularity in different stages of rat pancreatic carcinogenesis induced by azaserine and promoted by raw soya flour-containing pancreatotrophic diet. Besides the tumour samples taken at 6 (atypical acinar cell nodules), 15 (adenomas) and 20 (localised adenocarcinomas) months after carcino- gen initiation, we also investigated 3 control groups: tumour-bearing host tissue of azaserine-treated rats and normal tissue of untreated rats kept on standard or pancreatotrophic diet. In contrast with the usual microvessel counting on hot spots, we determined microvascular surface density (SV) and volume den- sity (VV) by electron microscopic morphometry. There was no significant difference in these respect between the control groups. At month 6 after the azaserine induction SV and VV showed slight, non- significant decrease as compared to the host control. Both values remained unchanged until the 15th month and increased significantly by the 20th month. These results may indicate comparable growth rate of tumour and new microvessels in the premalignant stages of carcinogenesis while a more intense angio- genesis than tumour growth afterwards.
Phytophthora alni is a species hybrid that causes a destructive root and collar rot disease of alders throughout Europe. Its subspecies, P. alni subsp. alni (Paa), P. alni subsp. uniformis (Pau) and P. alni subsp. multiformis (Pam) can be distinguished on the basis of phenotypic and genotypic traits. In this study, we report evidence of an unusual genomic combination of two subspecies occurring in two P. alni isolates from Hungary. These isolates, which had previously been identified as Paa using hybrid-specific PCR primers and morphological traits, exhibited a mitochondrial DNA restriction pattern identical to that of Pau. However, RAPD patterns and isozyme profiles of nuclear genes encoding glucose-phosphate isomerase (Gpi) and malate dehydrogenase (Mdh) of the two atypical isolates were identical to those found in all Paa isolates. Isozyme analysis also revealed a novel allele at the putative Mdh-1 locus in Paa and Pam isolates. The atypical Paa isolates have likely emerged as a result of hybridization events in the P. alni population between Paa and Pau .
Abstract
Epidemics and pandemics have happened throughout the history of mankind. Before the end of the 20th century, scientific progress successfully eradicated several of the pathogens. While no one has to be afraid of smallpox anymore, there are some new pathogens that have never caused human disease before. Coronaviruses are a family of enveloped RNA viruses. In the 21st century, three of them have caused serious pandemics, including severe acute respiratory syndrome in 2002 and Middle East Respiratory Syndrome in 2012. In 2019 severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) caused the coronavirus disease-19 (COVID-19) pandemic, which has destroyed hundreds of thousands of lives and continues to rage.
Studies involving morphological description with both dominant (RAPD) and codominant (SSR, isoenzyme) molecular markers were made on 28 maize inbred lines of known genetic background with a final aim of prediction of heterosis. The genetic distance and degree of relationship between the lines was determined using cluster analysis. Only a very limited extent of allele polymorphism could be detected in isoenzyme analyses as the 28 lines formed only 16 gel electrophoretic groups, indicating that certain lines had identical isoenzyme patterns. On the basis of RAPD and gene-specific microsatellite (SSR) markers, however, all the lines could be distinguished from each other. When the lines were grouped according to genetic background it was found that although the individual marker systems only partially reflected the actual relationships between the lines, a joint processing of the data, supplemented with morphological data, revealed a close correlation between the groups formed on the dendrogram and the genetic background.
Abstract
Purpose
The aim of this study was to assess longitudinal changes in retinal vessel density in diabetic patients using optical coherence tomography angiography (OCTA) to identify the most sensitive parameter for detecting retinopathy progression.
Methods
Patients with diabetes mellitus were enrolled in this study. Each study subject underwent two imaging sessions, during which three OCTA images of the macular area and three images of the optic nerve head were obtained. The two sessions took place one year apart. The OCTA imaging was performed using an AngioVue device. Superficial vessel density was evaluated in the central 3 mm and parafoveal area, and the nonflow area was measured using the built-in automated AngioAnalytics software of the Optovue system.
Results
This study included 78 eyes of 39 diabetic patients (age: 55.16 ± 13.73 years) with a mean of 7.70 ± 1.07 mmol L−1 HgA1c level at baseline. At the one-year visit, the eyes of the diabetic subjects had significantly lower superficial vessel density in the parafoveal macula compared to corresponding values at baseline (p < 0.05). There was no statistically significant difference between the baseline and one-year results for the other vascular density parameters and the foveal avascular zone (p > 0.05).
Conclusion
At the one-year follow-up, we found that vessel density had decreased in the parafoveal ring in these patients, while there was no significant change in other vascular parameters. This result suggests that superficial parafoveal capillary density is the most sensitive OCTA parameter that can be used as a biomarker for diabetic retinopathy progression. None of the other vascular density parameters nor the foveal avascular zone were able to indicate the subtle changes in retinal microcirculation due to the progression of diabetic microvasculopathy.
