Testing of biocidal properties of thermal insulation system during material life cycle

With the growing number of realized thermal insulation systems, fast growing number of buildings with facades attacked by microorganisms occurs. Such surface attack can occur even in the first years after thermal insulation completion, and it can be a serious problem in a very short time. Problem is both in realization and maintaining of thermal insulation, and directly in the used material. The paper presents results of laboratory experiments on resistance to biological attack, carried out for five commercial materials available on the Czech market. Before the experiments, materials were subjected to accelerated ageing for 4 and 10 years. Resistance testing comprises regulated application of algae and mould strains on samples and incubation in a defined environment. Materials resistant after ageing simulation of the longer time period were found as well as materials susceptible to attack already after completion of a facade set.

Protective Systems Ensuring Durability of Wooden Structures

Wood is a versatile material able to be used in a wide variety of situations and applications. Wood has also very good strength to weight ratio. Problem is degradation of wood due to bad external conditions. The protection of wood takes many forms including proper design detailing. The majority are directed towards the prevention of moisture access and weathering. However, there are also some design details that can also assist in reducing the risk of biological attack. Our work provides a background on a number of important subjects related to good performance of wooden structures. This paper deals with durability of wood, design for durability of wooden structures, surface modification of wood and also evaluation and monitoring of wooden structures.

Influence of selected storage temperatures on wood properties and its biological resistance after the use of methylxanthines

Methylxanthine’s fungicidal properties were investigated, with attention to the temperature of treatment. Caffeine and theophylline treatments of beech and spruce woods were applied for three months in the temperature range of -20 to 40 °C, simulating potential weather conditions in the European region and temperatures specific for various wood applications (cellars, wine cellars, room indoor temperatures, interior trusses). Effects of the selected temperatures were considered without the influence of the other possible factors, which have been considered in previous studies (e.g. effects of temperature in combination with other factors such as UV radiation, humidity, and chemical or biological degradation). Then, the specimens were exposed to a mix of molds and fungi for three months under controlled laboratory conditions in order to analyze a possible subsequent biological attack. The results did not show any effect of temperature of the methylxanthine treatment within the studied range on the organismal activity. Caffeine exhibited a better protective potential than theophylline and was more effective for spruce than for beech. The results indicated the suitability of caffeine for protection of spruce and spruce-based materials in interior applications at a stable temperature without significant effects of UV and humidity.

Liposomes Prevent In Vitro Hemolysis Induced by Streptolysin O and Lysenin

The need for alternatives to antibiotics in the fight against infectious diseases has inspired scientists to focus on antivirulence factors instead of the microorganisms themselves. In this respect, prior work indicates that tiny, enclosed bilayer lipid membranes (liposomes) have the potential to compete with cellular targets for toxin binding, hence preventing their biological attack and aiding with their clearance. The effectiveness of liposomes as decoy targets depends on their availability in the host and how rapidly they are cleared from the circulation. Although liposome PEGylation may improve their circulation time, little is known about how such a modification influences their interactions with antivirulence factors. To fill this gap in knowledge, we investigated regular and long-circulating liposomes for their ability to prevent in vitro red blood cell hemolysis induced by two potent lytic toxins, lysenin and streptolysin O. Our explorations indicate that both regular and long-circulating liposomes are capable of similarly preventing lysis induced by streptolysin O. In contrast, PEGylation reduced the effectiveness against lysenin-induced hemolysis and altered binding dynamics. These results suggest that toxin removal by long-circulating liposomes is feasible, yet dependent on the particular virulence factor under scrutiny.

Evaluation of the efficiency of the consolidation treatment with Paraloid B72, performed on artworks with degraded wood support

The aim of the study is to determine the efficiency of the consolidation treatment with Paraloid B 72, performed on wood degraded by biological attack. The method of determining the HM hardness is an original scientific method, that is minimally invasive and which indicates the level of damage to the substrate before the consolidation treatment and at the end of consolidation, allowing the evaluation of the process. The specimens are tested with the Mark 10 apparatus to determine the HM hardness, which can be related to a standardized hardness. Two consolidation steps are performed in Paraloid B72, 12% solubilized in Mixture (Ethyl Acetate and Toluene, 1:1). At the end of the consolidation, the hardness increases from 6.74 N/mm2 (37.11%) to 13.73 N/mm2 (75.61%), compared to a reference wood, which has a hardness of 18.16 N/mm2.

Extractive concentrations and cellular level distributions change radially from outer to inner heartwood in Scots pine

The heartwood of many wood species is rich in extractives, which improve the wood material’s resistance to biological attack. Their concentration is generally higher in outer than inner heartwood, but the exact radial changes in aging heartwood remain poorly characterized. This investigation studied these radial changes in detail in Scots pine (Pinus sylvestris L.), using radial sample sequences prepared from three different trees. Stilbene and resin acid contents were first measured from bulk samples, after which the extractive contents of individual heartwood annual rings were investigated using Raman spectroscopy and fluorescence microscopy. Raman imaging and fluorescence microscopy were also used to study the cellular level distributions of extractives in different annual rings. Although there were substantial differences between the trees, the content and distribution of stilbenes seemed to follow a general radial trend. The results suggest that stilbenes are absorbed into heartwood tracheid cell walls from small stilbene-rich extractive deposits over several years and then eventually transform into non-extractable compounds in aging heartwood. Resin acids followed no consistent radial trends, but their content was strongly connected to the frequency of large extractive deposits in latewood tracheid lumens. The results highlight the variability of heartwood extractives: their content and distribution vary not only between trees but also between and even within the annual rings of a single tree. This high variability is likely to have important effects on the properties of heartwood and the utilization of heartwood timber.

COVID-19: Pathogenesis and Pharmacological Basis for Use of Passive Antibody Therapy

Background: Coronaviruses (CoVs), having enveloped RNA of positive strand, are mainly responsible for enzootic infections in mammals. The mortality of CoVs has been proved as they can cross the species barrier very easily and infect humans. Most recently, the outbreak of coronavirus induced COVID-19 emerged in the city of Wuhan, Hubei province of China and became the third highly pathogenic coronavirus infecting nearly 230 countries. Objective: To review the literature available about pathogenic Coronavirures with emphasis on pathogenesis of COVID19, and passive antibody therapy prospective. Method: This study reviewed relevant published literature to provide (1) structural similarities between coronaviruses and therapeutic methodologies used on SARS-CoV, MERS treatment which might help scientists in understanding novel COVID-19 infection, (2) understanding COVID-19 pathogenesis that may help in identification of appropriate therapeutic targets to develop specific and effective anti-viral drug as well as immunizing agents against this novel emerging pathogen and (3) to discuss existing knowledge on the passive immune therapy against similar coronaviruses SARS-CoV and MERS-CoV with emphasis on COVID-19 pandemic treatment. Conclusion: COVID 19 coronavirus have shown resemblance to viral infections like SARS-CoV, MERS infection. Historically, it has been proved that prevention of disease when exposed to biological system is mainly a function of immune response of that infected individual. To fight against these infections, passive anibody therapy is the only available counter measure which could provide immediate immunity against infection. Passive antibody results in protection irrespective of the immune status of the host. This therapy can be advantageous in countering biological attack, post exposure preventions, low toxicity and peculiar activity.

Chaotic African Buffalo Optimization Based Efficient Key Mechanism in Categorized Sensor Networks

In recent days, Wireless Sensor Network (WSN) can be used to monitor the circumstances of various movable objects and several processes such as friendly forces monitoring, biological attack detection, fire detection and so on its applications are extended. To make all these applications reliable and secure, it is necessary to use cryptographic processes. The security of the whole network is depending on the strength of a generated key, the algorithm decides the size of the key handling and processing. In this research, a secure efficient key management scheme is proposed with the help of Chaotic African Buffalo Optimization (CABO) for wireless sensor networks. The evaluation of this method is made with the objective to improve the security strength and reduce the cost of resource. The traditional methods called genetic algorithm and an evolutionary algorithm named as Particle Swarm Optimization (PSO) is compared to verify the proposed scheme.