Cold stress effects on organelle ultrastructure in polar Caryophyllaceae species

Abstract: This study investigated leaf mesophyll cells of Caryophyllaceae plants growing in polar regions – Cerastium alpinum and Silene involucrata from the Hornsund region of Spitsbergen island (Svalbard Archipelago, Arctic), and Colobanthus quitensis from the Ad− miralty Bay region on King George Island (South Shetland Islands, West Antarctic). Ultra− structural changes were analyzed in mesophyll protoplasts of plants growing in natural Arctic and Antarctic habitats and plants grown in a greenhouse, including plants exposed to short−term cold stress under semi−controlled conditions. Cell organelles of plants growing in natural polar habitats and greenhouse−grown plants were characterized by significant mor− phological plasticity.Chloroplasts of plants studied in this work formed variously shaped pro− trusions and invaginations that visibly increased the contact area between adjacent cell com− partments and reduced the distance between organelles. S. involucrata plants grown under greenhouse conditions, tested by us in this work, were characterized by highly dynamic cell nuclei with single or multiple invaginations of the nuclear membrane and the presence of channels and cisternae filled with cytoplasm and organelles. Crystalline inclusion proteins were observed in the cell nuclei of C. quitensis between nuclear membranes and in the direct proximity of heterochromatin. Our study revealed significant conformational dynamics of organelles, manifested by variations in the optical density of matrices, membranes and envelopes, in particular in C. quitensis, which could suggest that the analyzed Caryophyllaceae taxa are well adapted to severe climate and changing conditions in polar regions

Vasodilatory efficacy and impact of papaverine on endothelium in radial artery predilatation for CABG surgery : in search for optimal concentration

Abstract Objective: The aim of this study was to compare the efficacy of two different papaverine concentrations (0.5 mg/ml and 2 mg/ml) for vasospasm prevention and their impact on endothelium integrity. Methods: We have studied distal segments of radial arteries obtained by no-touch technique from coronary artery bypass graft (CABG) patients (n=10). The vasodilatory effect of papaverine (concentrations of 0.5 mg/ml and 2 mg/ml) was assessed in vitro, in isometric tension studies using ex vivo myography (organ bath technique) and arterial rings precontracted with potassium chloride (KCl) and phenylephrine. The impact of papaverine on endothelial integrity was studied by measurement of the percentage of vessel's circumference revealing CD34 endothelial marker. Results: 2 mg/ml papaverine concentration showed stronger vasodilatatory effect than 0.5 mg/ml, but it caused significantly higher endothelial damage. Response to KCl was 7.35±3.33 mN for vessels protected with papaverine 0.5 mg/ml and 2.66±1.96 mN when papaverine in concentration of 2 mg/ml was used. The histological examination revealed a significant difference in the presence of undamaged endothelium between vessels incubated in papaverine 0.5 mg/ml (72.86±9.3%) and 2 mg/ml (50.23±13.42%), P=0.002. Conclusion: Papaverine 2 mg/ml caused the higher endothelial damage. Concentration of 0.5 mg/ml caused better preservation of the endothelial lining

Cold stress effects on organelle ultrastructure in polar Caryophyllaceae species

Abstract: This study investigated leaf mesophyll cells of Caryophyllaceae plants growing in polar regions -Cerastium alpinum and Silene involucrata from the Hornsund region of Spitsbergen island (Svalbard Archipelago, Arctic), and Colobanthus quitensis from the Ad− miralty Bay region on King George Island (South Shetland Islands, West Antarctic). Ultra− structural changes were analyzed in mesophyll protoplasts of plants growing in natural Arctic and Antarctic habitats and plants grown in a greenhouse, including plants exposed to short−term cold stress under semi−controlled conditions. Cell organelles of plants growing in natural polar habitats and greenhouse−grown plants were characterized by significant mor− phological plasticity. Chloroplasts of plants studied in this work formed variously shaped pro− trusions and invaginations that visibly increased the contact area between adjacent cell com− partments and reduced the distance between organelles. S. involucrata plants grown under greenhouse conditions, tested by us in this work, were characterized by highly dynamic cell nuclei with single or multiple invaginations of the nuclear membrane and the presence of channels and cisternae filled with cytoplasm and organelles. Crystalline inclusion proteins were observed in the cell nuclei of C. quitensis between nuclear membranes and in the direct proximity of heterochromatin. Our study revealed significant conformational dynamics of organelles, manifested by variations in the optical density of matrices, membranes and enve− lopes, in particular in C. quitensis, which could suggest that the analyzed Caryophyllaceae taxa are well adapted to severe climate and changing conditions in polar regions

Finansowe uwarunkowania decyzji ekonomicznych

Praca recenzowana / peer-reviewed pape

Marketing

Publikacja recenzowana / Peer-reviewed publicationZE WSTĘPU: Kolejny Zeszyt Naukowy jest zbiorem osiemnastu artykułów przygotowanych przez pracowników Wydziału Zarządzania i Marketingu. Publikacja obejmuj szeroki zakres tematyczny prezentowanych zagadnień, odnoszących się przede wszystkim do budowania przewagi konkurencyjnej firm, działających coraz częściej na rynkach międzynarodowych. W ustawicznie zmieniającym się otoczeniu globalnym pozostają do rozstrzygnięcia istotne problemy, związane z wyborem rynku docelowego, pozycjonowaniem produktów i ich cenowaniem, a także zarządzaniem finansami przedsiębiorstw - te ostatnie determinują realizację zadań wynikających z podjętych działań marketingowych

DNA replication defect in the Escherichia coli cgtA (ts) mutant arising from reduced DnaA levels

In Escherichia coli and other bacteria, the ribosome-associated CgtA GTP-binding protein plays a critical role in many basic cellular processes, including the control of DNA replication and/or segregation. However, the mechanism of this control is largely unknown. Here we report that ectopic expression of the dnaA gene partially restored both early growth in liquid medium and DNA synthesis defects of the cgtA (ts) mutant. Amounts of DnaA protein in the cgtA (ts) mutant incubated at elevated (42°C) temperature were significantly lower relative to wild-type bacteria. Both level of dnaA mRNA and transcriptional activity of the dnaA promoter- lacZ fusion were decreased in the CgtA-deficient cells. The effects of ectopic expression of dnaA were specific as analogous expression of another gene coding for a replication regulator, seqA , had no significant changes in growth and DNA synthesis in the cgtA mutant. Thus, it appears that the DNA replication defect in this mutant is a consequence of reduced DnaA levels.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/45857/1/203_2006_Article_99.pd

4C Mortality Score correlates with in-hospital functional outcome after COVID-19-associated ischaemic stroke

Aim of the study. The 4C Mortality Score was created to predict mortality in hospitalised patients with COVID-19 and has to date been evaluated only in respiratory system disorders. The aim of this study was to investigate its application in patients with COVID-19-associated acute ischaemic stroke (AIS).Clinical rationale for study. COVID-19 is a risk factor for AIS. COVID-19-associated AIS results in higher mortality and worse functional outcome. Predictors of functional outcome in COVID-19-associated AIS are required.Materials and methods. This was a retrospective observational study of patients with AIS hospitalised in seven neurological wards in Małopolska Voivodship (Poland) between August and December 2020. We gathered data concerning the patients’ age, sex, presence of cardiovascular risk factors, type of treatment received, and the presence of stroke-associated infections (including pneumonia, urinary tract infection and infection of unknown source). We calculated 4C Mortality Score at stroke onset, and investigated whether there was a correlation with neurological deficit measured using the National Health Institute Stroke Scale (NIHSS) and functional outcome assessed using the modified Rankin Scale (mRS) at discharge.Results. The study included 52 patients with COVID-19-associated AIS. The 4C Mortality Score at stroke onset correlated with mRS (rs = 0.565, p < 0.01) at discharge. There was also a statistically significant difference in the mean 4C Mortality Score between patients who died and patients who survived the stroke (13.08 ± 2.71 vs. 9.85 ± 3.47, p = 0.04).Conclusions and clinical implications. 4C Mortality Score predicts functional outcome at discharge in COVID-19-associated AIS patients

Zmiany skuteczności hedgingu delta z zastosowaniem opcji na WIG20

Purpose: Based on the research carried out by the author in 2007 and 2015, an increase in the effectiveness of delta hedging with the use of options on the WIG20 was found. The purpose of the study is to compare the results of the 2017–2018 delta hedging effectiveness studies with the results of previous studies, as well as to assess the changes in the effectiveness with an indication of possible causes. Design/methodology/approach: To compare the effectiveness of delta hedging, the estimated Value at Risk was used for unhedged and hedged portfolios in the analyzed periods. The results obtained on the basis of data from the years 2017–2018 were compared with the results for the data from 2007 and 2015. Findings: On the basis of the conducted research, the effectiveness of delta hedging using options on the Polish market can be generally stated, but the durability of the high effectiveness of delta hedging observed in 2015 cannot be stated. In the years 2017–2018, there was a decrease in the effectiveness of delta hedging associated with a significant decrease in liquidity on the option market. The research results highlight the importance of liquidity for the proper option pricing as well as for the possibility of risk reduction. Research limitations/implications: Some difficulty and limitation of the study were quite frequent lack of data regarding the options analyzed in the period 2017–2018. Originality/value: The value of the obtained results is increased by their uniqueness, as changes in the effectiveness of delta hedging on the Polish options market are not discussed in the literature by other authors. JEL: G11, G32, O16 Acknowledgements The paper was financed from funds allocated to the College of Management and Quality Sciences of the University of Economics in Krakow, as part of a grant for the maintenance of research potential. Suggested Citation: Węgrzyn, R. (2020). Changes in Effectiveness of Delta Hedging Using Options on the WIG20. Problemy Zarządzania (Management Issues), 18(4), 163–177.Cel: na podstawie przeprowadzonych przez autora badań w latach 2007 i 2015 stwierdzono wzrost skuteczności hedgingu delta z zastosowaniem opcji na WIG20. Celem pracy jest porównanie wyników badań skuteczności hedgingu delta z okresu 2017–2018 z wynikami poprzednich badań, a także ocena zmian skuteczności wraz ze wskazaniem możliwych przyczyn. Metoda: do porównania skuteczności hedgingu delta zastosowano oszacowaną wartość zagrożoną (Value at Risk) dla portfeli niezabezpieczonych i zabezpieczonych w analizowanych okresach. Wyniki uzyskane na podstawie danych z lat 2017–2018 porównano z wynikami dla danych z 2007 i 2015 roku. Wyniki: na podstawie przeprowadzonych badań można ogólnie stwierdzić skuteczność hedgingu delta z zastosowaniem opcji na polskim rynku, ale nie można stwierdzić trwałości wysokiej skuteczność hedgingu delta zaobserwowanej w 2015 roku. W latach 2017–2018 nastąpiło zmniejszenie skuteczności hedgingu delta powiązane ze znacznym spadkiem płynności na rynku opcji. Wyniki badań zwracają uwagę na znaczenie płynności dla właściwej wyceny opcji, a także możliwości ograniczania ryzyka. Ograniczenia badań: pewnym utrudnieniem i ograniczeniem badań były dość częste braki danych dotyczących analizowanych opcji w okresie 2017–2018. Oryginalność/wartość: wartość uzyskanych wyników zwiększa ich unikalność, gdyż zmiany efektywności hedgingu delta na polskim rynku opcji nie są poruszane w literaturze przez innych autorów. JEL: G11, G32, O16 Acknowledgements The paper was financed from funds allocated to the College of Management and Quality Sciences of the University of Economics in Krakow, as part of a grant for the maintenance of research potential. Suggested Citation: Węgrzyn, R. (2020). Changes in Effectiveness of Delta Hedging Using Options on the WIG20. Problemy Zarządzania (Management Issues), 18(4), 163–177

Skuteczność hedgingu dynamicznego z zastosowaniem opcji na WIG20 w aktualnych warunkach rynkowych

Based on previous research on the deviations of the prices of options on the WIG20 from the arbitrage restrictions and features, it was found that the number and scale of these deviations clearly decreased, thus improving the quality of the arbitrage pricing of options. The purpose of this work in this context is to determine the effectiveness of dynamic hedging using options on the WIG20 in current market conditions and to compare the results with the results of previously conducted research. The study was carried out using the historical scenario method based on data from 2017-2018 shared by the Warsaw Stock Exchange. To compare the effectiveness of dynamic hedging, Value at Risk was applied to the unhedged portfolio and portfolios hedged by a specific hedging method. Based on the research, it can be concluded that among the delta, delta-gamma and delta-gamma-vega hedging analyzed, the most effective solution in the current market conditions is delta hedging. The research results indicate that despite qualitative changes on the market that improve the option price relations the delta-gamma and delta-gamma-vega hedging are in practice worse solutions than delta hedging.Na podstawie przeprowadzonych wcześniej badań odchyleń cen opcji na WIG20 od określonych ograniczeń i właściwości arbitrażowych stwierdzono, że liczebność i skala tych odchyleń wyraźnie się zmniejszyły, poprawiając jakość arbitrażowej wyceny opcji. Cele artykułu to określenie skuteczności hedgingu dynamicznego z zastosowaniem opcji na WIG20 w aktualnych warunkach rynkowych i porównanie uzyskanych wyników z wynikami przeprowadzonych wcześniej analiz. Badanie przeprowadzono metodą scenariusza historycznego na podstawie danych z lat 2017-2018 udostępnionych przez GPW w Warszawie. Do porównania skuteczności hedgingu dynamicznego zastosowano oszacowaną wartość zagrożoną (VaR) dla portfeli niezabezpieczonych i zabezpieczonych określonymi metodami hedgingu. Stwierdzono, że wśród przeanalizowanych hedgingów delta, deltagamma i delta-gamma-vega najskuteczniejszym rozwiązaniem w obecnych warunkach rynkowych jest hedging delta. Mimo zmian jakościowych na rynku poprawiających relacje cenowe opcji hedgingi delta-gamma i delta-gamma-vega są w praktyce gorszymi rozwiązaniami niż hedging delta