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971.
The bis(cyclopentadienyl) complexes [Cp2Ti(dca)]2O and Cp2V(dca)2 (dca = dicyanamide) have been prepared by reaction of sodium dicyanamide with aqueous solution of titanocene dichloride and vanadocene dichloride, respectively. The X-ray structure analyses of both complexes confirmed monodentate coordination of dicyanamide ligand through the terminal nitrogen atom of cyano group. 相似文献
972.
Pavol Svorc Ivana Bacova Pavol Svorc Jr. Monika Nováková Sona Gresova 《Biological Rhythm Research》2016,47(1):103-110
Zoletil anaesthesia does not affect vital functions; however, there is no literature evidence regarding the effect of zoletil anaesthesia on the circadian rhythm(s) of vital functions. The aims of this study, with respect to dependence on the light–dark (LD) cycle under in vivo conditions in spontaneously breathing zoletil-anaesthetized rats, were to assess ECG parameters that may to predict development of ventricular arrhythmias and to assess arterial acid–base balance, which have the direct impact on the heart electrophysiology. The experiment was performed using zoletil-anaesthetized (30 mg/kg, i.p) female Wistar rats after adaptation to LD cycle (12 h:12 h). LD differences were found in heart rate, rectal temperature, electrophysiological myocardial parameters and acid–base balance. Animals were in systemic acidosis, hypoxia and hypercapnia in the both lighted periods of the regimen day. These results suggest that zoletil can be used in chronobiological studies investigating in vivo electrophysiological myocardial properties in rat models. 相似文献
973.
Yizhou Yu Giorgio Fedele Ivana Celardo Samantha H. Y. Loh L. Miguel Martins 《Cell death & disease》2021,12(7)
Alzheimer’s disease is the most common age-related neurodegenerative disorder. Familial forms of Alzheimer’s disease associated with the accumulation of a toxic form of amyloid-β (Aβ) peptides are linked to mitochondrial impairment. The coenzyme nicotinamide adenine dinucleotide (NAD+) is essential for both mitochondrial bioenergetics and nuclear DNA repair through NAD+-consuming poly (ADP-ribose) polymerases (PARPs). Here we analysed the metabolomic changes in flies overexpressing Aβ and showed a decrease of metabolites associated with nicotinate and nicotinamide metabolism, which is critical for mitochondrial function in neurons. We show that increasing the bioavailability of NAD+ protects against Aβ toxicity. Pharmacological supplementation using NAM, a form of vitamin B that acts as a precursor for NAD+ or a genetic mutation of PARP rescues mitochondrial defects, protects neurons against degeneration and reduces behavioural impairments in a fly model of Alzheimer’s disease. Next, we looked at links between PARP polymorphisms and vitamin B intake in patients with Alzheimer’s disease. We show that polymorphisms in the human PARP1 gene or the intake of vitamin B are associated with a decrease in the risk and severity of Alzheimer’s disease. We suggest that enhancing the availability of NAD+ by either vitamin B supplements or the inhibition of NAD+-dependent enzymes such as PARPs are potential therapies for Alzheimer’s disease.Subject terms: Metabolomics, Cell death in the nervous system, Alzheimer''s disease 相似文献
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977.
Eva Stod?lková Ivana Císa?ová Miroslav Kola?ík Milada Chudí?ková Petr Novák Petr Man Marek Kuzma Barbora Pavl? Jan ?erny Miroslav Flieger 《PloS one》2015,10(2)
Four strains of the fungus Quambalaria cyanescens (Basidiomycota: Microstromatales), were used for the determination of secondary metabolites production and their antimicrobial and biological activities. A new naphthoquinone named quambalarine A, (S)-(+)-3-(5-ethyl-tetrahydrofuran-2-yliden)-5,7,8-trihydroxy-2-oxo-1,4-naphthoquinone (1), together with two known naphthoquinones, 3-hexanoyl-2,5,7,8-tetrahydroxy-1,4-naphthoquinone (named here as quambalarine B, 2) and mompain, 2,5,7,8-tetrahydroxy-1,4-naphthoquinone (3) were isolated. Their structures were determined by single-crystal X-ray diffraction crystallography, NMR and MS spectrometry. Quambalarine A (1) had a broad antifungal and antibacterial activity and is able inhibit growth of human pathogenic fungus Aspergillus fumigatus and fungi co-occurring with Q. cyanescens in bark beetle galleries including insect pathogenic species Beauveria bassiana. Quambalarine B (2) was active against several fungi and mompain mainly against bacteria. The biological activity against human-derived cell lines was selective towards mitochondria (2 and 3); after long-term incubation with 2, mitochondria were undetectable using a mitochondrial probe. A similar effect on mitochondria was observed also for environmental competitors of Q. cyanescens from the genus Geosmithia. 相似文献
978.
Ivana Bajsanski Vesna Stojakovic Bojan Tepavcevic Marko Jovanovic Dejan Mitov 《仿生工程学报(英文版)》2017,14(3)
Windbreak fences in open and urban areas can be used to effectively reduce the wind velocity.In this paper we examine how the geometrical shape of the windbreak fence can optimally mitigate wind velocity.We propose an approach for windbreak fence design based on a bionic parametric model of the shark skin denticle geometry,which improves the reduction of the wind velocity around and behind the windbreak fences.The generative model was used to estimate improvements by variations in the parameters of the fence panel's geometrical shape,inspired by shark skin denticles.The results of the Computational Fluid Dynamics (CFD) analysis indicates that the fence surface inspired by shark skin performs much better than both flat and corrugated surfaces.Taking into account the complex geometry of the surface inspired by shark skin denticles,we propose a fabrication process using an expanded polystyrene foam (EPS) material,created using an industrial robot ann with a hot-wire tool.Creating EPS moulds for the shark skin denticle panels allows for a richer variety material to be used in the final design,leading both to higher efficiency and a more attractive design. 相似文献
979.
Ivana Markov Renata Koní
kov Kateina Vakov Martin Lení
ek Michal Kol Hynek Strnad Milue Hradilov Jana chov Jan Rasl Zuzana Klímov Tom Vomastek Ivana Nme
kov Petr Nachtigal Libor Vítek 《Journal of cellular and molecular medicine》2020,24(4):2402-2415
Arthrospira platensis, a blue‐green alga, is a popular nutraceutical substance having potent antioxidant properties with potential anti‐carcinogenic activities. The aim of our study was to assess the possible anti‐angiogenic effects of A platensis in an experimental model of pancreatic cancer. The effects of an A platensis extract were investigated on human pancreatic cancer cells (PA‐TU‐8902) and immortalized endothelial‐like cells (Ea.hy926). PA‐TU‐8902 pancreatic tumours xenografted to athymic mice were also examined. In vitro migration and invasiveness assays were performed on the tested cells. Multiple angiogenic factors and signalling pathways were analysed in the epithelial, endothelial and cancer cells, and tumour tissue. The A platensis extract exerted inhibitory effects on both migration and invasion of pancreatic cancer as well as endothelial‐like cells. Tumours of mice treated with A platensis exhibited much lesser degrees of vascularization as measured by CD31 immunostaining (P = .004). Surprisingly, the VEGF‐A mRNA and protein expressions were up‐regulated in pancreatic cancer cells. A platensis inhibited ERK activation upstream of Raf and suppressed the expression of ERK‐regulated proteins. Treatment of pancreatic cancer with A platensis was associated with suppressive effects on migration and invasiveness with various anti‐angiogenic features, which might account for the anticancer effects of this blue‐green alga. 相似文献
980.
Ram Maharjan Susanna Nilsson Judy Sung Ken Haynes Robert E. Beardmore Laurence D. Hurst Tom Ferenci Ivana Gudelj 《Ecology letters》2013,16(10):1267-1276
Understanding how populations and communities respond to competition is a central concern of ecology. A seminal theoretical solution first formalised by Levins (and re‐derived in multiple fields) showed that, in theory, the form of a trade‐off should determine the outcome of competition. While this has become a central postulate in ecology it has evaded experimental verification, not least because of substantial technical obstacles. We here solve the experimental problems by employing synthetic ecology. We engineer strains of Escherichia coli with fixed resource allocations enabling accurate measurement of trade‐off shapes between bacterial survival and multiplication in multiple environments. A mathematical chemostat model predicts different, and experimentally verified, trajectories of gene frequency changes as a function of condition‐specific trade‐offs. The results support Levins' postulate and demonstrates that otherwise paradoxical alternative outcomes witnessed in subtly different conditions are predictable. 相似文献