The Selected Writings of Jan Patočka : Care for the Soul

© Bloomsbury Publishing Plc 2021. This is the accepted manuscript version of a book chapter which has been published in final form at https://www.bloomsbury.com/uk/selected-writings-of-jan-patocka-9781350139091/Jan Patocka's contribution to phenomenology and the philosophy of history mean that he is considered one of the most important philosophers of the 20th century. Yet, his writing is not widely available in English and the Anglophone world remains rather unfamiliar with his work. In this new book of essential Patocka texts, of which the majority have been translated from the original Czech for the first time, readers will experience a general introduction to the key tenets of his philosophy. This includes his thoughts on the relationship between philosophy and political engagement which strike at the heart of contemporary debates about freedom, political participation and responsibility and a truly pressing issue for modern Europe, what exactly constitutes a European identity? In this important collection, Patocka provides an original vision of the relationship between self, world, and history that will benefit students, philosophers and those who are interested in the ideals that underpin our democracies

Influence of Freezing Water Samples Prior to Chemical Analysis

The need to collect and analyze samples of water resources periodically has been realized for many years by people concerned. with the use and preservation of water resources. As water use increased, routine analysis of water quality also increased. In order to obtain representative results of analyses, care must be taken to obtain samples which are representative of the existing field conditions. Care must also be taken to have a sample which is representative of the field conditions at the time the sample is being analyzed. The time lapse between collection and analysis of water samples can become quite lengthy for the following reasons: time of transport to the testing laboratory, lack of convenience or manpower, number of samples to be tested, and laboratory testing capacity. During the time lapse between collection and analysis, the composition of the sample may change because of the chemical reactions that constantly occur in all substances. Freezing has been used as a method to preserve the chemical quality of the sample at the time of collection. Therefore, a simple, practical water sample preservation method such as freezing would be very beneficial to a water quality surveillance program. A practical freezing process for preservation would involve the following: collection of representative samples, preservation by simply freezing in a convenient food storage freezer or locker, storage in the frozen state until the time the samples are to be analyzed, thawing the samples at room temperature, and, finally, analyses of the samples. A rapid freezing technique such as the utilization of dry ice and acetone seems to be less practical and may be dangerous. If the more feasible freezing process (food storage freezer) preserved. the chemical integrity of water samples, the process could easily be implemented. within a water quality surveillance program. A literature review revealed that adequate statistical evaluations of some of the freezing preservation processes were not made, and as a result, conflicting opinions on the effects of preservation by freezing prevailed. This research was undertaken to determine whether the freezing or thawing of water samples would significantly change the chemical quality of the samples. The decision to evaluate the data statistically was made in order to support the conclusions of this research project

Botulinum Toxin; Bioterror and Biomedicinal Agent

Botulinum toxin is a group of seven homologous, highly poisonous proteins isolated fromfermentation of the anaerobic bacterium Clostridium botulinum, which naturally occurs in soiland can grow on many meats and vegetables. Botulinum toxin causes neuromuscular disordercalled botulism, which is a potentially lethal disease. There are three types of botulism: Food,wound, and infant botulism. It can lead to death unless appropriate therapy is done. Due to theseverity and potency of botulinum toxin, its importance as a biological weapon is of majorconcern to public health officials. Nevertheless, botulinum toxin is also medicament

Settling of inertial particles in turbulent Rayleigh-Benard convection

The settling behaviour of small inertial particles in turbulent convection is a fundamental problem across several disciplines, from geophysics to metallurgy. In a geophysical context, the settling of dense crystals controls the mode of solidification of magma chambers and planetary-scale magma oceans, while rising of light bubbles of volatiles drives volcanic outgassing and the formation of primordial atmospheres. Motivated by these geophysical systems, we perform a systematic numerical study on the settling rate of particles in a rectangular two-dimensional Rayleigh-Benard system with Rayleigh number up to 10^12 and Prandtl number from 10 to 50. Under the idealized condition of spherically-shaped particles with small Reynolds number, two limiting behaviours exist for the settling velocity. On the one hand, Stokes' law applies to particles with small but finite response time, leading to a constant settling rate. On the other hand, particles with a vanishing response time are expected to settle at an exponential rate. Based on our simulations, we present a new physical model that bridges the gap between the above limiting behaviours by describing the sedimentation of inertial particles as a random process with two key components: i) the transport of particles from vigorously convecting regions into sluggish, low-velocity "piles" that naturally develop at the horizontal boundaries of the system, and ii) the probability that particles escape such low-velocity regions without settling at their base. In addition, we identify four distinct settling regimes and analyze the horizontal distribution of sedimented particles. For two of these regimes settling is particularly slow and the distribution is strongly non-uniform, with dense particles being deposited preferentially below major clusters of upwellings.Comment: 30 pages, 18 figures, submitted to Phys. Rev. Fluid

Prophylaxis Against Nerve Agent Intoxications

The acute toxicity of organophosphates is usually attributed to their irreversible inhibitionof an enzyme acetylcholinesterase that hydrolyses the neurotransmitter acetylcholine. Theresultant increase in concentration of acetylcholine at the cholinergic synapses of the peripheraland central nervous system, and neuromuscular junction is manifested by over-stimulation ofthe cholinergic neurotransmission. Current antidotal regimens for organophosphate poisoningconsisting of a post-exposure therapy with anticholinergics such as atropine, acetylcholinesterasereactivators (oximes), benzodiazepines have some limitations. Therefore, effective prophylaxisbefore intoxication is of a special interest. Four fundamental prophylactic methods are: (i)protection of acetylcholinesterase against irreversible inhibition by organophosphates usingdifferent reversible inhibitors, (ii) protection against neurotoxic effect of organophosphates usingbenzodiazepines, memantine, NMDA receptor blockers, (iii) administration of cholinesterasepreparations of different sources (sometimes commercially available at present) acting asbioscavengers, and (iv) gene therapy being a new treatment modality under intensive researchusing enzymes hydrolysing/splitting organophosphates with the aim to eliminate toxic agentbefore it is transported to the target organs

Biohazards of Protein Biotoxins

Biotoxins are toxic substances produced by a living organism that cause diseases in humanbeings, animals, or plants. The agent may be lethal or incapacitating. The new, emerging threatagents are biotoxins produced by animals, plants, fungi, and bacteria. Many types of organismsproduce substances that are toxic to humans. Examples of such biotoxins are botulinum toxin,tetanus toxin, and ricin. Several bioactive molecules produced by the pharmaceutical industrycan be even more toxic than the classical chemical warfare agents. Such new agents, like thebiotoxins and bioregulators, often are called mid-spectrum agents. The threat to human beingsfrom agents developed by modern chemical synthesis and by genetic engineering also must beconsidered, since such agents may be more toxic or more effective in causing death orincapacitation than classical warfare agents. By developing effective medical protection andtreatment against the most likely chemical and mid-spectrum threat agents, the effects of suchagents in a war scenario or following a terrorist attack can be reduced. Toxin-mediated diseaseshave made human beings ill for millennia. The use of biological agents as weapons of terror hasnow been realised, and separating naturally occurring disease from bioterroristic events hasbecome an important public health goal

A Review on the Synthesis and Bioactivity Aspects of Beauvericin, a Fusarium Mycotoxin

Beauvericin (BEA) is an emerging Fusarium mycotoxin that contaminates food and feeds globally. BEA biosynthesis is rapidly catalyzed by BEA synthetase through a nonribosomal, thiol-templated mechanism. This mycotoxin has cytotoxicity and is capable of increasing oxidative stress to induce cell apoptosis. Recently, large evidence further shows that this mycotoxin has a variety of biological activities and is being considered a potential candidate for medicinal and pesticide research. It is noteworthy that BEA is a potential anticancer agent since it can increase the intracellular Ca2+ levels and induce the cancer cell death through oxidative stress and apoptosis. BEA has exhibited effective antibacterial activities against both pathogenic Gram-positive and Gram-negative bacteria. Importantly, BEA exhibits an effective capacity to inhibit the human immunodeficiency virus type-1 integrase. Moreover, BEA can simultaneously target drug resistance and morphogenesis which provides a promising strategy to combat life-threatening fungal infections. Thus, in this review, the synthesis and the biological activities of BEA, as well as, the underlying mechanisms, are fully analyzed. The risk assessment of BEA in food and feed are also discussed. We hope this review will help to further understand the biological activities of BEA and cast some new light on drug discovery