Microbiological hazards in HVAC systems and possibilities of their elimination

Tato práce se zabývá vzduchotechnickými systémy a popisuje jejich základní části. Jsou zmíněny nejdůležitější mikrobiologická rizika, jež se mohou objevit v různých prvcích, jako jsou bakterie, viry a plísně. Poslední část práce se zabývá možnostmi čištění a údržbou vzduchotechniky. Ty jsou potřebné k zabránění růstu a mikrobů a zajištění bezporuchového provozu.This thesis deals with HVAC systems and describes some of their the basic parts. There are mentioned the most important microbiological hazards, which can occur in different parts, such as bacteria, viruses and molds. The last part of the thesis deals with possibilities of maintenance and cleaning of HVAC systems. They are needed to prevent microbes to grow and to provide failure-free operation.

Are mutagenic non D-loop direct repeat motifs in mitochondrial DNA under a negative selection pressure?

Non D-loop direct repeats (DRs) in mitochondrial DNA (mtDNA) have been commonly implicated in the mutagenesis of mtDNA deletions associated with neuromuscular disease and ageing. Further, these DRs have been hypothesized to put a constraint on the lifespan of mammals and are under a negative selection pressure. Using a compendium of 294 mammalian mtDNA, we re-examined the relationship between species lifespan and the mutagenicity of such DRs. Contradicting the prevailing hypotheses, we found no significant evidence that long-lived mammals possess fewer mutagenic DRs than short-lived mammals. By comparing DR counts in human mtDNA with those in selectively randomized sequences, we also showed that the number of DRs in human mtDNA is primarily determined by global mtDNA properties, such as the bias in synonymous codon usage (SCU) and nucleotide composition. We found that SCU bias in mtDNA positively correlates with DR counts, where repeated usage of a subset of codons leads to more frequent DR occurrences. While bias in SCU and nucleotide composition has been attributed to nucleotide mutational bias, mammalian mtDNA still exhibit higher SCU bias and DR counts than expected from such mutational bias, suggesting a lack of negative selection against non D-loop DR

Is mitochondrial DNA turnover slower than commonly assumed?

Mutations arise during DNA replication due to oxidative lesions and intrinsic polymerase errors. Mitochondrial DNA (mtDNA) mutation rate is therefore closely linked to the mitochondrial DNA turnover process, especially in post mitotic cells. This makes the mitochondrial DNA turnover rate critical for understanding the origin and dynamics of mtDNA mutagenesis in post mitotic cells. Experimental mitochondrial turnover quantification has been based on different mitochondrial macromolecules, such as mitochondrial proteins, lipids and DNA, and the experimental data suggested highly divergent turnover rates, ranging from over 2days to about 1year. In this article we argue that mtDNA turnover rate cannot be as fast as is often envisaged. Using a stochastic model based on the chemical master equation, we show that a turnover rate corresponding to mtDNA half-life in the order of months is the most consistent with published mtDNA mutation level

Maximizing signal-to-noise ratio in the random mutation capture assay

The ‘Random Mutation Capture' assay allows for the sensitive quantitation of DNA mutations at extremely low mutation frequencies. This method is based on PCR detection of mutations that render the mutated target sequence resistant to restriction enzyme digestion. The original protocol prescribes an end-point dilution to about 0.1 mutant DNA molecules per PCR well, such that the mutation burden can be simply calculated by counting the number of amplified PCR wells. However, the statistical aspects associated with the single molecular nature of this protocol and several other molecular approaches relying on binary (on/off) output can significantly affect the quantification accuracy, and this issue has so far been ignored. The present work proposes a design of experiment (DoE) using statistical modeling and Monte Carlo simulations to obtain a statistically optimal sampling protocol, one that minimizes the coefficient of variance in the measurement estimates. Here, the DoE prescribed a dilution factor at about 1.6 mutant molecules per well. Theoretical results and experimental validation revealed an up to 10-fold improvement in the information obtained per PCR well, i.e. the optimal protocol achieves the same coefficient of variation using one-tenth the number of wells used in the original assay. Additionally, this optimization equally applies to any method that relies on binary detection of a small number of template

Effects of Lithium on Age-related Decline in Mitochondrial Turnover and Function in Caenorhabditis elegans

Aging has been associated with the accumulation of damages in molecules and organelles in cells, particularly mitochondria. The rate of damage accumulation is closely tied to the turnover of the affected cellular components. Perturbing mitochondrial turnover has been shown to significantly affect the rate of deterioration of mitochondrial function with age and to alter lifespan of model organisms. In this study, we investigated the effects of upregulating autophagy using lithium in Caenorhabditis elegans. We found that lithium treatment increased both the lifespan and healthspan of C. elegans without any significant change in the mortality rate and oxidative damages to proteins. The increase in healthspan was accompanied by improved mitochondrial energetic function. In contrast, mitochondrial DNA copy number decreased faster with age under lithium. To better understand the interactions among mitochondrial turnover, damage, and function, we created a mathematical model that described the dynamics of functional and dysfunctional mitochondria population. The combined analysis of model and experimental observations showed how preferential (selective) autophagy of dysfunctional mitochondria could lead to better mitochondrial functionality with age, despite a lower population size. However, the results of model analysis suggest that the benefit of increasing autophagy for mitochondrial function is expected to diminish at higher levels of upregulation due to a shrinking mitochondrial populatio

The Concept of Resilience between State Security and Sovereign Security: a Look at Policy Challenges and Interests of the UK

Resilienz hat sich in den letzten Jahren zu einem Schlüsselbegriff in nationalen und internationalen Sicherheitskonzepten entwickelt. Der derzeitige Stand der Forschung verbindet das Konzept vielfach mit einer neoliberalen Politik des staatlichen Rückzugs aus seiner sicherheitspolitischen Verantwortung, oder mit einem nahezu totalitären Zugriff auf "resiliente Subjekte". Anhand einer empirischen Untersuchung der britischen Resilienz-Politik zeigt dieser Artikel, dass keiner dieser Ansätze zutrifft. Vielmehr entpuppt sich Resilienz als ein profaner Ansatz des Katastrophenschutzes auf lokaler Ebene. Allerdings ermöglicht Resilienz damit erst wieder die Sicherheitsverantwortlichkeit des Staates, der an seinem Versprechen der "umfassenden Sicherheit" gescheitert ist. Damit ist Resilienz nicht als Rückzug souveräner Sicherheitspolitik zu verstehen, sondern als staatliches Micro-Management der potenziellen Katastrophen. Resilienz löst daher die Idee einer souveränen Sicherheit auch nicht ab, sondern verbindet das sicherheitspolitisch Mögliche und Unmögliche in einem Resilienz-Sicherheits-Nexus.Resilience is on the rise in security policies, at the international as well as at the national level. Current academic research often links resilience with either the neoliberal retreat of the state and the respective attempt of 'governing from a distance', or with an almost totalitarian grasp of 'resilient subjects', or both. Against the background of the application of resilience in UK security policy, this article argues that resilience does neither of these. Instead, it unfolds as a rather mundane endeavour focused on micro-practices of civil emergency response at the local level. In doing so, resilience enables the repackaging of 'unbound security', which was doomed to fail in delivering its promise. It is, however, neither offering another promise nor symbolising a retreat from state responsibility, but engages in a defensive micro-management of potential catastrophe. Resilience hence does not replace security as a practice of the state deriving from its sovereignty, but links up with it to create a nexus between the doable and the undoable, the resilience-security-nexus

Identity Construction in Insurgent Movements: a Case Study of the Colombian Ejército de Liberación Nacional

In Studien im Bereich der Friedens- und Konfliktforschung und der kritischen Terrorismusforschung wurde Identität als Faktor herangezogen um die Beständigkeit von Guerilla/Terrorismus-Gruppierungen zu erklären. Dieser Artikel fokussiert sich auf die Identitätskonstruktion der linken, kolumbianischen Guerilla-Gruppierung "Ejército de Liberación Nacitonal" (ELN; Deutsch: Nationale Befreiungsarmee). Als marxistisch-leninistische Organisation ist es das erklärte Ziel der ELN den Kapitalismus zu überwinden. In der Perzeption der ELN erfordert die Überwindung des Kapitalismus die Überwindung des Individualismus und darum kreiert die ELN "kollektive Persönlichkeiten". In diesem Artikel werden die Mechanismen an Hand derer eine "kollektive Persönlichkeit" indoktriniert wird aufgezeigt. Diese spezifische Identitätskonstruktion ist der Hauptfaktor, warum Menschen in dieser Gruppierung bleiben und kämpfen, wodurch folglich die Beständigkeit der Gruppierung abgesichert wird.In conflict studies, identity has been posited as an explanatory factor of the resilience of insurgencies. This article focuses on the identity formation of the National Liberation Army (ELN), a leftist insurgency group in Colombia. As Marxist-Leninist organisation, the ELN aims to overcome capitalism. In their perception, this is possible via the transformation of the individual into a 'collective personality'. Along the dimensions of 'content' and ‘contestation’ we will demonstrate the mechanisms they impose for such identity formation. Identity, as we will argue, is a main factor in explaining why people participate in this insurgency and thereby enhance its resilience

Hybrid Rules with Well-Founded Semantics

A general framework is proposed for integration of rules and external first order theories. It is based on the well-founded semantics of normal logic programs and inspired by ideas of Constraint Logic Programming (CLP) and constructive negation for logic programs. Hybrid rules are normal clauses extended with constraints in the bodies; constraints are certain formulae in the language of the external theory. A hybrid program is a pair of a set of hybrid rules and an external theory. Instances of the framework are obtained by specifying the class of external theories, and the class of constraints. An example instance is integration of (non-disjunctive) Datalog with ontologies formalized as description logics. The paper defines a declarative semantics of hybrid programs and a goal-driven formal operational semantics. The latter can be seen as a generalization of SLS-resolution. It provides a basis for hybrid implementations combining Prolog with constraint solvers. Soundness of the operational semantics is proven. Sufficient conditions for decidability of the declarative semantics, and for completeness of the operational semantics are given

Design of Drive Modul and Return Unit of a Belt Conveyor

Tato diplomová práce se zabývá návrhem hnací a vratné jednotky dopravníku s plochým řemenem. Konstrukce dopravníku je navržena pomocí zadaných parametrů. Tento dopravník slouží k paletové přepravě. Práce obsahuje rešerši, která se zabývá výrobci paletových dopravníků a jejich pohonem. Součástí práce je kontrola navržených uzlů.This diploma thesis deals with design of drive modul and return unit of a belt conveyor. Construction of conveyor is designed using the specified parameters. This conveyor is used for pallet transport. The thesis contains a research of manufactures of pallet conveyors and their drive. Part of the thesis is control of designed nodes

Drying of biomass

Tato práce se zabývá sušením biomasy, především sušením drobné dřevní hmoty. Porovnány jsou různé metody sušení jako je pásové sušení, fluidní sušení a bubnové sušení společně s jejich výhodami a nevýhodami. Je navrhnuto základní technologické schéma sušící linky. V poslední části práce je zpracován výpočet bubnové sušárny zadaného výkonu a je provedena ekonomická rozvaha.This thesis deals with the drying of biomass, especially drying of small wood mass. The various drying methods, such as belt drying, fluidized bed drying and drum drying are compared including their advantages and disadvantages. It is suggested basic technological scheme of drying line. The last part of the thesis deals with a calculation of drum dryer of specified performance and economic balance is made.