"Člověk jako badatel nehraje se Satanem o svou duši, ale s přirodou o poznání a moc." William Crookes. Sir William Crookes (1832-1919) byl jedním z nejvýznamějších britských fyziků a chemiků druhé poloviny devatenáctého a začátku dvacátého století. Tento text se zabývá jeho životem a vědeckým odkazem, kterým je například objev thallia, zkoumání čtvrtého stavu hmoty, podíl na objevování řady vzácných plynů, vynález prvního radiometru a také spinthariskopu, jednoho z prvních detektorů ionizujícího záření. Některé Crookesovy myšlenky si ještě za jeho života našly cestu také k českému čtenáři a právě tyto texty jsou hlavním tématem našeho článku., Sir William Crooker (1832-1919) was one of the most notable British physicists and chemists active in the second half of the 19th century. The subject of this article is his life and scientific legacy, e.g. the discovery of thallium, exploration of the fourth state of matter, participation in discovering certain rare gases, or invention of the first radiometer and spinthariscope. Some ot his ideas vere presented to the Czech audience during the course of his life and it is these texts which are "the golden thread" of this article., Pavel Pecháček, Petr Průša., and Obsahuje seznam literatury
Článek ukazuje, jak nám zdánlivě jednoduché přístupy a nástroje založené na fyzikálních a chemických principech a poznatcích umožní přežít v nehostinných podmínkách mimo civilizaci. obecné úvahy jsou ilustrovány konkrétními příklady - rozděláváním ohně, čištěním a dezinfekcí vody atp., This article deals with using physics and chemistry to make possible our survival in the wilderness. Contemporary physics and chemistry is responsible for progress in the field of outdoor pursuits. Outdoor equipment and skills have become high-tech. Thus, use of basic physical and chemical principles in outdoor activities is now often overlooked although they can be of great use at moments when we lose technological superiority because of unexpected situations and events at extreme conditions. Then we are forced to improvise. Usefulness of applying physical and chemical principles is demonstrated on flame-resistant fiberglass wick, simple lighters, thermos used for cooking and sperilizing water, utilization electrolysis of brine for generating chlorine for water disinfection, use of PET bottles as simple pressurized filtration device for water purification, and so on., Ladislav Sieger., and Obsahuje bibliografii
Damage induced in DNA by numerous chemical and physical factors as well as spontaneously formed imperfections in DNA structure pose a threat to all organisms. To counteract this threat, living cells have evolved a series of DNA repair pathways to correct DNA lesions affecting base pairings or the structure of DNA. Today we understand, in a large part, the molecular mechanisms of these pathways in detail due to the pioneering studies by Tomas LIndahl, Paul Modrich and Aziz Sancar, which opened up this field of research. Tomas Lindahl discovered the molecular machinery of base excision repair - the main cell defence against endogeneous DNA damage. Aziz Sancar characterised, at the molecular level, details of the mechanisms of nucleotide excision repair - the major repair system of DNA damage caused by environmental factors such as UV-irradiation and various genotoxic chemicals including chemotherapeutic agents. Paul Modrich uncovered a mismatch repair - the way how cells resolve errors which occur during DNA replication. Therefore, the Royal Swedish Academy of Sciences awarded jointly Lindahl, Modrich, and Sancar the Nobel Prize in Chemistry 2015 for their "Mechanistic studies of DNA repair". In this paper, we briefly summarise the results of their work., Miroslav Piršel., and Obsahuje seznam literatury