(Bio)degradable polymeric materials for sustainable future—Part 3: Degradation studies of the PHA/wood flour-based composites and preliminary tests of antimicrobial activity

© 2020 The Authors. Published by MDPI. This is an open access article available under a Creative Commons licence. The published version can be accessed at the following link on the publisher’s website: https://doi.org/10.3390/ma13092200The need for a cost reduction of the materials derived from (bio)degradable polymers forces research development into the formation of biocomposites with cheaper fillers. As additives can be made using the post-consumer wood, generated during wood products processing, re-use of recycled waste materials in the production of biocomposites can be an environmentally friendly way to minimalize and/or utilize the amount of the solid waste. Also, bioactive materials, which possess small amounts of antimicrobial additives belong to a very attractive packaging industry solution. This paper presents a study into the biodegradation, under laboratory composting conditions, of the composites that consist of poly[(R)-3-hydroxybutyrate-co-4-hydroxybutyrate)] and wood flour as a polymer matrix and natural filler, respectively. Thermogravimetric analysis, differential scanning calorimetry and scanning electron microscopy were used to evaluate the degradation progress of the obtained composites with different amounts of wood flour. The degradation products were characterized by multistage electrospray ionization mass spectrometry. Also, preliminary tests of the antimicrobial activity of selected materials with the addition of nisin were performed. The obtained results suggest that the different amount of filler has a significant influence on the degradation profile.Published onlin

Pseudomorphs of barite and biogenic ZnS after phyto-crystals of calcium oxalate (whewellite) in the peat layer of a poor fen

Pseudomorphs of barite (BaSO(4)) and Cd-rich ZnS after whewellite (CaC(2)O(4)·H(2)O) occur within remnants of Scots pine bark tissues in the peat layer of a poor fen located near a zinc smelter in south Poland. A two-step formation of the pseudomorphs is postulated based on SEM observations: (1) complete dissolution of whewellite, possibly caused by oxalotrophic bacteria, and (2) subsequent bacterially induced precipitation of barite and spheroidal aggregates of ZnS together with galena (PbS) in voids left by the dissolved whewellite crystals. Local increase in pH due to microbial degradation of whewellite, elevated concentrations of Zn(II) and Ba(II) in pore water due to the decomposition of atmospheric particles of sphalerite and barite in the acidic (pH 3.5–3.8) environment, oxidation of S species during drying and rewetting of the peat layer, and subsequent partial reduction of sulfate anions by sulfur-reducing bacteria were all factors likely involved in the crystallization of ZnS and barite in the microenvironment of the post-whewellite voids

Forensic engineering of advanced polymeric materials Part IV: Case study of oxo-biodegradable polyethylene commercial bag – Aging in biotic and abiotic environment

This is an accepted manuscript of an article published by Elsevier in Waste Management on 03/04/2017, available online: https://doi.org/10.1016/j.wasman.2017.03.043 The accepted version of the publication may differ from the final published version.The public awareness of the quality of environment stimulates the endeavor to safe polymeric materials and their degradation products. The aim of the forensic engineering case study presented in this paper is to evaluate the aging process of commercial oxo-degradable polyethylene bag under real industrial composting conditions and in distilled water at 70 °C, for comparison. Partial degradation of the investigated material was monitored by changes in molecular weight, thermal properties and Keto Carbonyl Bond Index and Vinyl Bond Index, which were calculated from the FTIR spectra. The results indicate that such an oxo-degradable product offered in markets degrades slowly under industrial composting conditions. Even fragmentation is slow, and it is dubious that biological mineralization of this material would occur within a year under industrial composting conditions. The slow degradation and fragmentation is most likely due to partially crosslinking after long time of degradation, which results in the limitation of low molecular weight residues for assimilation. The work suggests that these materials should not be labeled as biodegradable, and should be further analyzed in order to avoid the spread of persistent artificial materials in nature

Forensic engineering of advanced polymeric materials—part V: Prediction studies of aliphatic–aromatic copolyester and polylactide commercial blends in view of potential applications as compostable cosmetic packages

The main aim of the present study was to determine the behavior of the specimens from Ecovio, in the form of dumbbell-shaped samples and films, during degradation in selected cosmetic ingredients such as water and paraffin. The (bio)degradation test of the prototype cosmetic package (sachet) made from a PBAT (poly[(1,4-butylene adipate)-co-(1,4-butylene terephthalate)]) and PLA (polylactide) blend was investigated under industrial composting conditions, and compared with the sample behavior during incubation in cosmetic media at 70 °C. During the degradation tests, the changes of the samples were evaluated using optical microscopy, 1H NMR (proton nuclear magnetic resonance) and GPC (gel permeation chromatography) techniques. The structures of the degradation products were investigated using ESI-MSn (mass spectrometry with electrospray ionization on positive and negative ions) analysis. The thermal properties of selected materials were determined by DSC (differential scanning calorimetry) and TGA (thermogravimetric analysis) analysis. It was concluded that the PBAT and PLA blend studied had a good stability during aging in cosmetic media, and could be recommended for long-shelf-life compostable packaging of cosmetics, especially with oily ingredients.National Science Centre, Poland (grant numbers 2016/21/D/ST8/01993, 2013/11/B/ST5/02222), University of Wolverhampto

Quantification of intracellular payload release from polymersome nanoparticles

Polymersome nanoparticles (PMs) are attractive candidates for spatio-temporal controlled delivery of therapeutic agents. Although many studies have addressed cellular uptake of solid nanoparticles, there is very little data available on intracellular release of molecules encapsulated in membranous carriers, such as polymersomes. Here, we addressed this by developing a quantitative assay based on the hydrophilic dye, fluorescein. Fluorescein was encapsulated stably in PMs of mean diameter 85 nm, with minimal leakage after sustained dialysis. No fluorescence was detectable from fluorescein PMs, indicating quenching. Following incubation of L929 cells with fluorescein PMs, there was a gradual increase in intracellular fluorescence, indicating PM disruption and cytosolic release of fluorescein. By combining absorbance measurements with flow cytometry, we quantified the real-time intracellular release of a fluorescein at a single-cell resolution. We found that 173 ± 38 polymersomes released their payload per cell, with significant heterogeneity in uptake, despite controlled synchronisation of cell cycle. This novel method for quantification of the release of compounds from nanoparticles provides fundamental information on cellular uptake of nanoparticle-encapsulated compounds. It also illustrates the stochastic nature of population distribution in homogeneous cell populations, a factor that must be taken into account in clinical use of this technology.</p

Coexistence of mental and somatic diseases and difficulties in diagnosis and working with mentally ill people

AbstractIntroduction and purpose:The co-occurrence of mental illness and somatic diseases is a relationship confirmed by researchers in the fields of clinical medicine, health psychology or neuroscience. This article aims to present and discuss the interrelationship between mental and somatic diseases and to present issues related to the process of diagnosis.State of knowledge (brief description):Depression, schizophrenia, eating disorders and anxiety disorders are mental illnesses cited among researchers on the basis of studies as particularly prone to somatic comorbidities. Among somatic diseases, on the other hand, cancer is cited as the most frequently implicated in psychiatric comorbidity. However, this is not a clear-cut problem, as the impact of somatic and mental illnesses on each other can be bidirectional. Diagnosis of these requires a physician to have a great deal of factual knowledge and great vigilance in conducting an interview that may be conducted not only with the patient, but also with his family or environment.Summary:Working with people who are both mentally and somatically ill is a job that requires knowledge that combines both disciplines. Data indicate that 20-35% of patients with chronic somatic disease also have an additional psychiatric diagnosis; somatization of mental problems is a common phenomenon in outpatient treatment

COVID-19 pandemic: disease impact on nervous system, cognitive functioning and mental health

Introduction and purpose:COVID-19, as an unknown disease until 2019, has posed and continues to pose a great challenge to the world of science and the people facing it. The purpose of this article is to present the possible consequences of experiencing COVID-19 disease and the pandemic itself in light of mental health and the organism functioning in the cognitive area, taking into account the impact of COVID-19 on the nervous system.State of knowledge (brief description):Coronaviruses are enveloped, positive single-stranded large RNA viruses. COVID-19 is a disease caused by the SARS-CoV-2 virus – its first case was reported in 2019 in Wuhan, China. Human coronaviruses can exhibit neuroinvasive, neurotropic and neurovirulent, SARS-CoV-2 also. In addition to symptoms and complications in the respiratory system, symptoms and complications are also encountered in the nervous system area; cognitive functioning may also be impaired. The pandemic as a phenomenon in itself and the outbreak of COVID-19 can carry very serious consequences from the mental health field. Among these are the problem of social isolation and its consequences or the impact of the disease and pandemic on well-being. Unfortunately, the time that has elapsed since the first cases of the disease and the amount of research does not allow a clear determination of the complications and consequences of the pandemic, but certain trends and phenomena are regularly studied and described.Summary:Existing research and the state of the art strongly underscore that COVID-19 and its pandemic could impinge on the mental health of people around the world. Changes in the nervous system and cognitive functioning are also observed as a result of contracting COVID-19. Science currently has no clear answers as to how long certain complications will persist and exactly what their genesis is – further research is recommended to explain them as precisely as possible

3D-printed polyester-based prototypes for cosmetic applications—future directions at the forensic engineering of advanced polymeric materials

Knowledge of degradation and impairment phenomena of (bio)degradable polymeric materials under operating conditions, and thus the selection of test procedures and prediction of their behavior designates the scope and capabilities as well as possible limitations of both: the preparation of the final product and its durability. The main novelty and objective of this research was to determine the degradation pathways during testing of polylactide and polylactide/polyhydroxyalkanoate materials made with three-dimensional printing and the development of a new strategy for the comprehensive characterization of such complex systems including behavior during waste disposal. Prototype objects were subjected to tests for damage evolution performed under simulating operating conditions. The reference samples and the tested items were characterized by gel permeation chromatography and differential scanning calorimetry to determine changes in material properties. The studies showed that: polyhydroxyalkanoate component during accelerated aging and degradation in environments rich in microorganisms accelerated the degradation of the material; paraffin accelerates polylactide degradation and slows degradation of polyhydroxyalkanoate-based material; under the influence of an environment rich in enzymes, paraffin contamination accelerates biodegradation; under the influence of natural conditions, paraffin contamination slowed degradation; the processing conditions, in particular the printing orientation of individual parts of the container, influenced the material properties in its various regions, affecting the rate of degradation of individual parts.European Regional Development Fun

Water tunnel simulation of the internal flow of a segmented arc heater

A water tunnel study was undertaken to determine the flow-field properties and basic gas dynamic process in the High Enthalpy Ablation Test (HEAT-Hl) Arc heater. A twice-scale model simulating the inviscid circulation and internal geometry of the arc heater was tested at two Reynolds numbers, and visual data of the flow field were obtained. Results indicate that a good correlation exists between the flow anomalies visible in the water tunnel and some of the operational problems present in the arc heater. The knowledge gained from this study will be used to enhance basic understanding of the physics of the arc heater flow