53 research outputs found

    The Critical Length is a Good Measure to Distinguish between Stick Balancing in the ML and AP Directions

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    Seven novice subjects participated in experiments of stick balancing on a linear track in the anterior-posterior (AP) and the medio-lateral (ML) directions. The goal of the experiments was to test how the depth perception in the subjects' AP direction affects balancing performance compared to balancing in the ML direction, where depth perception does not play a role. It is easier to balance longer sticks than shorter ones, therefore balancing performance is measured by the length of the shortest stick that subjects can balance. Subjects were found to be able to balance shorter sticks in the ML direction than in the AP direction: the ratio of the shortest stick lengths in the ML direction relative to the AP direction was in average 0.53. Thus, the additional challenge posed by depth perception in the AP direction is clearly observable. Additionally, repeated trials were carried out for 5 consecutive days to assess the development of balancing skill by using stabilometry analysis. The maximal balance time of the subjects significantly increased with the days of practice

    A cilindrospermopszin cianobaktérium - alga interakcióban betöltött lehetséges szerepének vizsgálata

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    A kiterjedt litorális régióval rendelkező vizekben jelentős a fitoplankton és fitobentosz taxonok kapcsolata. Előbbiek több módon is képesek befolyásolni a bentonikus közösségek egyedszámát és összetételét. Munkánk során a planktonikus cilindrospermopszin-termelő Aphanizomenon ovalisporum (Cyanobacteria) és egy bentikus Chlorococcum faj (Chlorophyta) közti interakciós kapcsolatokat vizsgáltuk kevert tenyészetekben, illetve tanulmányoztuk az A. ovalisporum teljes sejtkivonatának hatását a Chlorococcum faj növekedésére és tápanyag-felvételére. Kevert tenyészetekben mindkét faj sejtszáma alacsonyabb volt a kontroll tenyészetekénél, négyszeres A. ovalisporum sejtszám esetén a Chlorococcum növekedése 77%-os gátlást szenvedett, azonban a tápoldatban cilindrospermopszint nem sikerült kimutatni. Az Aphanizomenon sejtkivonattal történő kezelés esetén is gátlás volt megfigyelhető már a kísérlet 7. napján is. A legnagyobb mennyiségben hozzáadott cianobaktérium kivonat a Chlorococcum tenyészetek növekedésében jelentős, de az együttnevelésnél megfigyelttől kisebb mértékű (50%-os) gátlást okozott. A kevert tenyészetekben a sejtszám függvényében jelentős változások mutatkoztak a tápanyagfelvételben, a kivonattal való kezelés eredményei alapján azonban úgy tűnik, hogy az A. ovalisporum kivonat nem befolyásolja a zöldalga normál tápanyag felvételi dinamikáját

    Salt Tolerance and Desalination Abilities of Nine Common Green Microalgae Isolates

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    In recent years, decline of freshwater resources has been recognized as one of the main environmental problems on global level. In addition to the increasing extent of primary salinization due to climate change, secondary salinization caused by human interventions is also a significantly increasing problem, therefore, the development of various chemical-free, biological desalination and removal procedures will become increasingly important. In the present study, the salinity tolerance, salinity, and nutrient reducing ability of nine common freshwater microalgae species from the genera Chlorella, Chlorococcum, Desmodesmus, Scenedesmus, and Monoraphidium were investigated. Our results proved that the studied green microalgae species are halotolerant ones, which are able to proliferate in environments with high salt concentrations. Furthermore, most of the species were able to reduce conductivity and remove significant amounts of chloride (up to 39%) and nutrients (more than 90% nitrate). The results proved that nitrate removal of the studied species was not influenced by salt concentration, only indirectly via growth inhibition. However, the results also highlighted that N:P ratio of the medium has primarily importance in satisfactory phosphorous removal. It can be concluded that assemblages of the studied microalgae species could be able to adapt to changing conditions even of salt-rich wastewaters and improve water quality during bioremediation processes

    Image guided high-dose-rate brachytherapy versus volumetric modulated arc therapy for head and neck cancer

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    Background The aim of the study was to present dosimetric comparison of image guided high-dose-rate brachytherapy (IGBT) with volumetric modulated arc therapy (VMAT) for head and neck cancer regarding conformity of dose distribution to planning target volume (PTV) and doses to organs at risk (OARs). Patients and methods Thirty-eight consecutive patients with T1-4 mobile tongue, floor of mouth and base of tongue cancer treated with IGBT were selected. For these patients additional VMAT treatment plans were also prepared using identical computed tomography data. OARs and PTV related parameters (e.g. V98, D0.1cm3, Dmean, etc.) were compared. Results Mean V98 of the PTV was 90.2% vs. 90.4% (p > 0.05) for IGBT and VMAT, respectively. Mean D0.1cm3 to the mandible was 77.0% vs. 85.4% (p 0.05). Dmean to ipsilateral and contralateral submandibular glands was 16.4% vs. 21.9% (p > 0.05) and 8.2% vs. 16.9% (p < 0.05), respectively. Conclusions Both techniques showed excellent target coverage. With IGBT dose to normal tissues was lower than with VMAT. The results prove the superiority of IGBT in the protection of OARs and the important role of this invasive method in the era of new external beam techniques

    Loss of the starvation-induced gene Rack1 leads to glycogen deficiency and impaired autophagic responses in Drosophila

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    Autophagy delivers cytoplasmic material for lysosomal degradation in eukaryotic cells. Starvation induces high levels of autophagy to promote survival in the lack of nutrients. We compared genome-wide transcriptional profiles of fed and starved control, autophagy-deficient Atg7 and Atg1 null mutant Drosophila larvae to search for novel regulators of autophagy. Genes involved in catabolic processes including autophagy were transcriptionally upregulated in all cases. We also detected repression of genes involved in DNA replication in autophagy mutants compared with control animals. The expression of Rack1 (receptor of activated protein kinase C 1) increased 4.1- to 5.5-fold during nutrient deprivation in all three genotypes. The scaffold protein Rack1 plays a role in a wide range of processes including translation, cell adhesion and migration, cell survival and cancer. Loss of Rack1 led to attenuated autophagic response to starvation, and glycogen stores were decreased 11.8-fold in Rack1 mutant cells. Endogenous Rack1 partially colocalized with GFP-Atg8a and early autophagic structures on the ultrastructural level, suggesting its involvement in autophagosome formation. Endogenous Rack1 also showed a high degree of colocalization with glycogen particles in the larval fat body, and with Shaggy, the Drosophila homolog of glycogen synthase kinase 3B (GSK-3B). Our results, for the first time, demonstrated the fundamental role of Rack1 in autophagy and glycogen synthesis

    Re-analysis of the Hungarian amyotrophic lateral sclerosis population and evaluation of novel ALS genetic risk variants.

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    Amyotrophic lateral sclerosis (ALS) is a presently incurable neurodegenerative disease. Some genes have a causal relationship to ALS, others act as susceptibility and/or risk factors. We aimed to elucidate the role of 14 ALS-related genes in the Hungarian ALS population of 183 patients. Mutation screening of major ALS genes was performed. SMN1 and SMN2 genes were examined by multiplex ligation-dependent probe-amplification assay; intermediate repeat expansions in the ATXN1 and ATXN2 genes were analyzed by fragment analysis. Additional variants in putative ALS genes were screened from previously acquired next generation sequencing data. We confirmed the repeat expansion of the C9orf72, ATXN1 and ATXN2 genes as ALS risk factors in this Hungarian cohort. Additionally, we identified a pathogenic SOD1 mutation and suggested its founder effect. A likely pathogenic variant in the MFSD8 gene was detected, and variants of interest were uncovered in the ANXA11 and GLT8D1 genes. We provide valuable data as part of the growing body of work on population-specific aspects of the genetic background of ALS
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