Prevention of ventilator-associated pneumonia

AbstractInvasive mechanical ventilation (IMV) represents a risk factor for the development of ventilator-associated pneumonia (VAP), which develops at least 48h after admission in patients ventilated through tracheostomy or endotracheal intubation. VAP is the most frequent intensive-care-unit (ICU)-acquired infection among patients receiving IMV. It contributes to an increase in hospital mortality, duration of MV and ICU and length of hospital stay. Therefore, it worsens the condition of the critical patient and increases the total cost of hospitalization. The introduction of preventive measures has become imperative, to ensure control and to reduce the incidence of VAP. Preventive measures focus on modifiable risk factors, mediated by non-pharmacological and pharmacological evidence based strategies recommended by guidelines. These measures are intended to reduce the risk associated with endotracheal intubation and to prevent microaspiration of pathogens to the lower airways

Enzymatic polymerization of phenolic compounds

Phenolics are natural compounds which contains hydroxyl group bonded to aromatic hydrocarbon ring. These compounds can be divided into two categories depending on the oxidation state of the central pyran ring: flavonoids and non-flavonoids. It is important to highlight the excellent properties of the phenolic compounds, such as anti-inflammatory, antimicrobial, and antioxidant activity. It has been described that the oxidation of phenolic compounds enhances its antimicrobial properties since the resulting polymers can contribute to the microorganism’s toxification. The polymerization reaction can be achieved by different biocatalysts such as oxidoreductases, namely laccases and peroxidases. Laccases use molecular oxygen as a co-substrate, being therefore the perfect co-substrate. Depending on the structure of the phenolic compound, namely the number of hydroxyl groups, the enzymatic polymerization can be performed via laccase or using laccase-mediator systems (LMSs). On the first reaction, the phenolic compound is oxidized and the resulting phenoxy radicals conduct to polymers formation through recombination processes. On the second method, the phenolic compound oxidation is mediated by redox species yielding the polyphenols formation. Any of these two routes allows the polymerization of phenolic products with enhanced properties

Chemically modified lipase from Thermomyces lanuginosus with enhanced esterification and transesterification activities - Front cover

The Front Cover shows a super catalyst (SC) lipase obtained through chemical modification for the production of several industrial products like ester-based compounds. In their Full Paper, J. Noro etal. studied the impact of the chemical modification of lipase from Thermomyces lanuginosus with dodecyl aldehyde, on its esterification and transesterification activity. The enzyme, modified with four dodecyl chains, showed an outstanding improvement of the catalytic performance for both reactions, comparing to the unmodified lipase. The most notorious results were achieved when longer chain-length alcohols were used for the transesterification of p-nitrophenyl palmitate and for the esterification of oleic acid. The novel enzyme modification strategy developed by the authors, resulted in the transformation of a super catalyst, with countless fields of applications, including the production of ester-based products for cosmetic and medical fields. More information can be found in the Full Paper by J. Noro etal.info:eu-repo/semantics/publishedVersio

Effect of a peptide in cosmetic formulations for hairhumidity-control

Humidity affects hair by changing the surface texture of the fiber. In higher humidity conditions, it is verified an increase of water uptake, which causes the swelling of the hair fibers. This leads to the extension of the hair cuticles and consequent increased friction between fibers, which causes static and an increase in the volume of hair tresses. However, these changes are distinct in different types of ethnic hair, where Caucasian Brown hair evidences a higher increase in hair tresses volume. We tested the application of several climate control formulations with and without a keratinbased peptide. The hair tresses treated with the formulations containing the peptide showed reduced volume change even after several hours of high humidity conditions. Due to its chemical nature, the peptide has affinity towards the hair fiber providing long-lasting moisture resistance and allowing it application in climate control formulations

On the robustness to corrosion in the life cycle assessment of an existing reinforced concrete bridge

Management of existing structures has traditionally been based on condition assessment, based on visual inspections, disregarding the susceptibility of different structural types to aging and deterioration. Robustness, as a measure of the effects of unpredictable damage to structural safety can be a complementary information to the results of inspection. Although robustness has mostly been used to evaluate the consequences of extreme events, a similar framework can be used to investigate the result of aging, allowing a better understanding of the potential effects of deterioration and allowing a better allocation of available maintenance funding. In this work, a probabilistic structural robustness indicator is used to quantify the susceptibility of structures to corrosion. The methodology is exemplified through a case study comprising an existing reinforced concrete bridge deck, heavily damaged due to reinforcement corrosion, and finally demolished due to safety concerns. Robustness measures the bridge deck safety tolerance to reinforcement corrosion. The principal effects of corrosion, including loss of area and bond between concrete and steel are modelled using a non-linear finite-element model, coupled with a Response Surface Method to compute the bridge reliability as a function of the corrosion level, and finally used to assess robustness. Results show that the redundancy of the bridge allows significant redistribution of loads between elements with different corrosion levels. As a result, the bridge presents significant robustness and tolerance to reinforcement corrosion

Biotechnological applications of mammalian odorant-binding proteins

The olfactory system of mammals allows the detection and discrimination of thousands of odors from the environment. In mammals, odorant-binding proteins (OBPs) are considered responsible to carry odorant molecules across the aqueous nasal mucus to the olfactory receptors (ORs). The three-dimensional structure of these proteins presents eight antiparallel ?-sheets and a short ?-helical segment close to the C terminus, typical of the lipocalins family. The great ability of OBPs to bind differentiated ligand molecules has driven the research to understand the mechanisms underlying the OBP function in nature and the development of advanced biotechnological applications. This review describes the role of mammalian OBPs in the olfactory perception, highlighting the influence of several key parameters (amino acids, temperature, ionic strength, and pH) in the formation of the OBP/ligand complex. The information from the literature regarding OBP structure, affinity, the strength of binding, and stability inspiring the development of several applications herein detailed.This study was financially supported by the Portuguese Foundation for Science and Technology (Fundac¸~ao para a Ciencia e a Tecnologia) under the scope of the strategic funding of UID/BIO/04469/2019 unit and BioTecNorte operation [NORTE-01-0145-FEDER-000004] funded by European Regional Development Fund under the scope of Norte2020 – Programa Operacional Regional do Norte. F.G. thanks Fundac~ao para a Ci^ encia e a Tecnologia for their funding [SFRH/BD/114684/2016].info:eu-repo/semantics/publishedVersio

Characterization and stability of free and immobilized laccase in the dyestar dyeing effluent

In this study the stability (in terms of half-life time) and decolourisation efficiency of free and immobilised laccase was determined in four industrial dyeing effluents. The dyeing liquors composition and the chemical structure of the dyes influence significantly the stability and the decolourisation ability of the enzyme. The dyeing in enzymatically decolourised Reactive Black 5 effluent provided consistency of the colour with both bright and dark dyes. Additionally the number of washing cycles necessary to remove the hydrolyzed dyestuff from dyed textiles was reduced using an enzymatic pre-treatment. In decolourisation experiments with immobilised laccase, two phenomenons were observed - initial decolourisation due to adsorption on the support and dye degradation due to the enzyme action. This research focuses on the stability and decolourisation ability of free and immobilised laccase in industrial dyeing effluents and their reuse for dyeing. In our experiments the stability of the immobilised laccase in dyeing liquors was unexpectedly lower than the stability of the free enzyme. The stability of the laccase in dyeing effluents is a result of the additive effect of all components presented. The decrease of enzymatic activity could be associated with the potential protein – dyeing effluent components interactions. Azoaromatic sulfonate dye anions could provide enzyme stabilisation. However, the structure of the immobilised laccase possibly became less accessible than the free enzyme for interaction with the anionic dyes, and thereby the stabilisation was not efficient. Non-ionic surfactants present in the dyeing liquors are able to stabilise the enzyme in solution by formation of a surrounding shell. The surfactant stabilisation was effective only on free enzyme. The salts in the dyebaths also displayed enzyme stabilising properties. The presence of CrVI and CrIII in the mordant dyeing effluent could cause significant loss of activity. The colour removal with immobilized laccase is due to the additive effects of dye-support adsorption, dye-protein adsorption and enzymatic dye degradation. In the decolourisation experiments carried out in pure dyes, the higher the hydrophilicity of the dye, the lower was the decolourisation. The Reactive Blue 158 adsorbed on the alumina support could act as mediator in laccase-assisted reactions, explaining the higher decolourisation of Reactive Black 5 with immobilized enzyme. The decolourisation efficiency in dyeing effluents was affected by the stabilization/destabilisation interactions in the dyeing formulation. Acceptable colour difference was achieved in dyeing with dyebaths prepared with laccase decolourised Reactive Black 5 effluent. Enzymatic treatment of dyed textiles provided water savings, reducing the number of the after-dyeing washing cycles.E

Functionalization of bacterial cellulose nonwoven by poly(fluorophenol) to improve its hydrophobicity and durability

The present study aims to improve the hydrophobicity and durability of bacterial cellulose (BC) nonwoven by functionalization with poly(fluorophenol). To this end, laccase was first entrapped onto BC and then used to polymerize the fluorophenol {4-[4-(trifluoromethyl) phenoxy] phenol} in-situ. The polymerization of fluorophenol by laccase was confirmed through 1H NMR and MALDI-TOF analyses. The effect of poly(fluorophenol) on BC nonwoven was determined by evaluation of the surface hydrophobicity and olephobicity properties such as water contact angle (WCA), oil contact angle (OCA), surface energy and water/oil absorption time. After BC functionalization with poly(fluorophenol) (20 mM), the WCA increased from 54.5 ± 1.2° to 120 ± 1.5° while the surface energy decreased (11.58 ± 1.4 mN/m). The OCA was also increased from 46.5 ± 2.5° to 87 ± 2° along to the decrease of surface energy (8.7 ± 1.5°). X-ray photoelectron spectroscopy (XPS) analysis confirmed an increase in the fluorine content in BC from 5.27 to 17.57%. The findings confirmed the polymerization of fluorophenol by laccase and its entrapment onto a BC nanofiber structure. The durability of the functionalization with poly(fluorophenol) was confirmed by evaluating the washing fastness, tensile strength after washing and dimensional stability. The results indicate that the functionalized BC nonwoven had higher tensile strength (×10 times) and better dimensional stability (30%) than the non-functionalized BC nonwoven material.This work was supported by the Portuguese Foundationfor Science and Technology (FCT) under the scope of thestrategic funding of UID/BIO/04469/2019 unit and Bio-TecNorteoperation (NORTE-01-0145-FEDER-000004). This work wasalso supported by the National Research Foundation of Korea(NRF) grant funded by the Korea government (MSIT) (No. NRF-2019R1A2C1009217).info:eu-repo/semantics/publishedVersio

The structural properties of odorants modulate their association to human odorant binding protein

The binding of known odorant molecules to the human odorant-binding protein (hOBP) was evaluated in silico. Docking experiments elucidate the preferable binding site and binding affinity of odorant molecules to hOBP. The physicochemical properties molecular weight (MW), vapor pressure (Vp), hydrophobicity level (logP), number of double bonds (NºDB), degree of unsaturation (DoU) and the chemical classification, were selected for the study of odorant modulation. Here, these properties were analyzed concerning 30 pleasant and 30 unpleasant odorants, chosen to represent a wide variety of compounds and to determine their influence on the binding energy to hOBP. Our findings indicate that MW, logP and Vp are the most important odorant variables, directly correlated to odorant-binding energies (DGbinding) towards hOBP. Understanding how the odorants behave when complexed with the OBP in human olfaction opens new possibilities for the development of future biotechnological applications, including sensory devices, medical diagnosis, among others.The following funding is acknowledged: the authors thank the support received from the Portuguese Foundation for Science and Technology (FCT) through the strategic funding of UID/BIO/04469/2019 unit and BioTecNorte Operation (NORTE-01-0145-FEDER-000004) funded by the European Regional Development Fund under the scope of Norte2020 - Programa Operacional Regional do Norte.info:eu-repo/semantics/publishedVersio