Self-templating assembly of soft microparticles into complex tessellations.

Encoding Archimedean and non-regular tessellations in self-assembled colloidal crystals promises unprecedented structure-dependent properties for applications ranging from low-friction coatings to optoelectronic metamaterials1-7. Yet, despite numerous computational studies predicting exotic structures even from simple interparticle interactions8-12, the realization of complex non-hexagonal crystals remains experimentally challenging13-18. Here we show that two hexagonally packed monolayers of identical spherical soft microparticles adsorbed at a liquid-liquid interface can assemble into a vast array of two-dimensional micropatterns, provided that they are immobilized onto a solid substrate one after the other. The first monolayer retains its lowest-energy hexagonal structure and acts as a template onto which the particles of the second monolayer are forced to rearrange. The frustration between the two lattices elicits symmetries that would not otherwise emerge if all the particles were assembled in a single step. Simply by varying the packing fraction of the two monolayers, we obtain not only low-coordinated structures such as rectangular and honeycomb lattices, but also rhomboidal, hexagonal and herringbone superlattices encoding non-regular tessellations. This is achieved without directional bonding, and the structures formed are equilibrium structures: molecular dynamics simulations show that these structures are thermodynamically stable and develop from short-range repulsive interactions, making them easy to predict, and thus suggesting avenues towards the rational design of complex micropatterns.

Levels of IgE sensitization drive symptom thresholds in allergic rhinitis.

BACKGROUND: Allergic rhinitis (AR) is a common respiratory disease encompassing a variety of phenotypes. Patients can be sensitized to 1 or more allergens. There are indications that polysensitization is associated with more severe disease. However, the extent to which the level of sensitization is associated with clinical disease variability, underlying the distinct nature of AR from AR+ conjunctivitis or AR+ asthma, is not known. OBJECTIVE: To evaluate phenotypical differences between monosensitized and polysensitized patients with AR and to quantify their symptomatic variability. METHODS: A total of 565 patients with a confirmed diagnosis of AR were included in this cross-sectional study. Of those, 155 were monosensitized and 410 were polysensitized. Interactions between sensitization levels and the reporting of different symptoms of AR and co-morbidities, disease duration, and impact were assessed. Furthermore, patients were stratified into monosensitized, oligosensitized, and polysensitized to assess whether the effect of sensitization on the phenotype was ranked. RESULTS: Polysensitized patients reported itchy eyes significantly more often (P = .001) and had a higher number of ocular (P = .005), itch-related (P = .036), and total symptoms (P = .007) than monosensitized patients. In addition, polysensitized adults and children more often reported wheeze (P = .015) and throat-clearing (P = .04), respectively. Polysensitization was associated with more burdensome AR based on a visual analog scale (P = .005). Increased sensitization level was reflected in more itchy eyes, a higher number of ocular, itch-related, and total number of symptoms, and disease burden. CONCLUSION: With an increasing number of sensitizations, patients with AR experience an increased diversity of symptoms. Multimorbidity-related symptoms increase with sensitization rank, suggesting organ-specific thresholds.

Evidence on the genotoxic and ecotoxic effects of PFOA, PFOS and their mixture on human lymphocytes and bacteria.

Considering that the PFOA and PFOS are widely spread chemicals with harmful effects in human and environmental health as well as the increasing interest of the scientific community in the implications that might present especially when they co-exist, this study aims to assess their harmful impacts, both individually and as a mixture on human lymphocytes and aquatic microorganisms. The cytokinesis-block micronucleus (CBMN) assay was used to examine their potential for cytotoxicity and genotoxicity towards human cells, and Microtox assay using Aliivibrio fischeri assay was used to estimate the environmental risk. Regarding the human lymphocytes, the tested concentrations ranged between 250 and 1000 µg L-1, for all cases. PFOA increased slightly the frequency of micronuclei (MN) but without statistical significance. In the case of PFOS, our results showed a dose-dependent increase in the frequency of micronuclei which showed a statistically significant difference (p < 0.001) at 1000 µg L-1, which is the highest studied concentration. Regarding the CBPI index, statistically significant (p < 0.05, p < 0.01, and p < 0.001 respectively) differences were observed at all studied concentrations of PFOS, compared to the control. The mixture was found to be more cytotoxic and genotoxic than the individual tested compounds, causing a higher decrease at the CBPI index even in lower concentrations and increase at the MN frequencies. Aliivibrio fischeri was exposed to various concentrations in the range of 0.5 µg L-1- 20 mg L-1, for 5 and 15 min and significant increase in the inhibition percentage at the highest tested concentration of their mixture after 15 min was observed.

Extraction of High Value Products from Zingiber officinale Roscoe (Ginger) and Utilization of Residual Biomass.

Zingiber officinale Roscoe (ginger) is a plant from the Zingiberaceae family, and its extracts have been found to contain several compounds with beneficial bioactivities. Nowadays, the use of environmentally friendly and sustainable extraction methods has attracted considerable interest. The main objective of this study was to evaluate subcritical propane (scPropane), supercritical CO2 (scCO2), and supercritical CO2 with ethanol (scCO2 + EtOH) as co-solvent methods for the extraction of high value products from ginger. In addition, the reuse/recycling of the secondary biomass in a second extraction as a part of the circular economy was evaluated. Both the primary and the secondary biomass led to high yield percentages, ranging from 1.23% to 6.42%. The highest yield was observed in the scCO2 + EtOH, with biomass prior used to scCO2 extraction. All extracts presented with high similarities as far as their total phenolic contents, antioxidant capacity, and chemical composition. The most abundant compounds, identified by the two different gas chromatography-mass spectrometry (GC-MS) systems present, were a-zingiberene, ß- sesquiphellandrene, a-farnesene, ß-bisabolene, zingerone, gingerol, a-curcumene, and γ-muurolene. Interestingly, the reuse/recycling of the secondary biomass was found to be promising, as the extracts showed high antioxidant capacity and consisted of significant amounts of compounds with beneficial properties.

Traumatic lumbar hernia: A systematic review of the literature.

PURPOSE: Traumatic lumbar hernia (TLH) constitutes a protrusion of content through a defect in the posterior abdominal wall, as a result of injury. This rare entity has been described in limited number of cases. METHODS: A systematic review of the literature was performed according to the meta-analysis of observational studies in epidemiology guidelines. The English literature from 1990 until 2021 was reviewed, using PubMed, EMBASE and Google Scholar bibliographic databases, to identify case reports and case series with patients that were diagnosed with TLH. For each eligible study, demographics, clinical presentation, hernia characteristics, preoperative imaging investigations, operation details, and postoperative data were extracted for assessment. Statistical analysis was performed on SPSS, version 20.0. RESULTS: A total of 62 studies were included for review, with 164 patients with TLH. Mean age was (42.6 ± 14.3) years (47.6% males, 31.1% females, gender not specified in 35 cases). Mean diameter of hernia neck was (6.3 ± 3.1) cm, while the triangles of Petit and Grynfeltt were affected in 74.5% and 14.6%, respectively. Patients diagnosed in the emergency setting account for 54.2%, with CT scan establishing diagnosis in all but one case (97.7%). A delayed diagnosis was made in 45.8%, at a mean 1 year following trauma. Flank bulging (82.8%) and chronic back pain (34.3%) were the most frequent symptoms. In both delayed and acute group, open surgery (63.6% and 92.3%, respectively) was the preferred surgical approach. Postoperative complications were reported in 11.4% of acute and 15.0% of delayed patients. Hernia recurrence was 7%. CONCLUSIONS: TLH is uncommon with 164 cases described since 1990. CT scan is the gold standard in diagnosis. Open surgery is generally the preferred approach, particularly in the emergency setting. Acute TLH can be treated either by primary suture repair or mesh, depending on the local conditions, whereas delayed cases usually require a mesh.

Critical View of Safety in Laparoscopic Cholecystectomy: A Systematic Review of Current Evidence and Future Perspectives.

BACKGROUND: The Critical View of Safety (CVS) has been increasingly recognised as the standard method for identification of the cystic structures, to prevent vasculobiliary injuries during laparoscopic cholecystectomy, however, its adoption has been anything but universal. A significant proportion of surgeons has a poor understanding of the three requirements. To bridge this gap between theory and practice, we aimed to summarise the available evidence on CVS, emphasising on current debates and future perspectives. METHOD: We systematically reviewed the literature (1995-2021), to identify studies reporting on the CVS. Eligible articles were classified according to methodology and key idea. A quantitative analysis was performed to evaluate effectiveness of the CVS in preventing bile duct injury (BDI). RESULTS: 150 relevant articles were identified, focusing on six main points, (1) safety and effectiveness, (2) intraoperative documentation, (3) complementary imaging techniques, (4) bail-out alternatives, (5) adoption among surgeons, and (6) education and training. The quantitative analysis included 11 studies, with 10,938 cases. Overall, the CVS was achieved in 92.5%. Conversion rate was 4.8%. CVS-related BDI was 0.09% (0.05% technical errors and 0.04% misidentification errors). CONCLUSION: Routine application of the CVS reduces BDI, but does not eliminate them altogether. Besides operative notes, the CVS should be documented by an imaging modality of sufficient quality. When the CVS cannot be safely established, the threshold for bail-out alternatives or complementary imaging should be low. Adoption by the surgical community worldwide shows great variability and focus should be placed on training through structured educational modules.

Patient consultations during SARS-CoV-2 pandemic: a mixed-method cross-sectional study in 16 European countries.

INTRODUCTION: Remote consultations help reduce contact between people and prevent cross-contamination. Little is known about the changes in consultation in European rural primary care during the SARS-CoV-2 (COVID-19) pandemic. The purpose of this mixed-methods cross-sectional study was to find out more about the effects of the pandemic on changes in patient consultations in European rural primary care. METHODS: A key informant survey from 16 member countries of the European Rural and Isolated Practitioners Association (EURIPA) was undertaken using a self-developed questionnaire. The steering committee of this project, called EURIPA Covid-19 study, developed a semi-structured questionnaire with 68 questions, 21 of which included free-text comments. Proportions were calculated for dichotomized or categorized data, and means were calculated for continuous data. Multivariate analysis by logistic regression model was used to assess the association of multiple variables. RESULTS: A total of 406 questionnaires from primary care providers (PCPs) in 16 European countries were collected; 245 respondents (60.5%) were females, 152 PCPs were rural (37.5%), 124 semi-rural (30.5%). Mean age of the respondents was 45.9 years (standard deviation (SD) 11.30) while mean seniority (length of experience) was 18.2 years (SD 11.6). A total of 381 (93.8%) respondents were medical doctors. Significant differences were found between countries in adopting alternative arrangements to face-to-face consultation: remote teleconsultation is well appreciated by both healthcare professionals and patients, but the most common way of remote consultation remains telephone consultation. A factor significantly inversely associated with the adoption of video consultation was the seniority of the PCP (odds ratio 1.19, 95% confidence interval 1.02-1.40, p=0.03). CONCLUSION: Telephone consultation is the most common form of remote consultation. The adoption of video-consultation is inversely related to the seniority of the informants.

Near-zero surface pressure assembly of rectangular lattices of microgels at fluid interfaces for colloidal lithography.

Understanding and engineering the self-assembly of soft colloidal particles (microgels) at liquid-liquid interfaces is broadening their use in colloidal lithography. Here, we present a new route to assemble rectangular lattices of microgels at near zero surface pressure relying on the balance between attractive quadrupolar capillary interactions and steric repulsion among the particles at water/oil interfaces. These self-assembled rectangular lattices are obtained for a broad range of particles and, after deposition, can be used as lithography masks to obtain regular arrays of vertically aligned nanowires via wet and dry etching processes.

Revisiting Amyand's Hernia: A 20-Year Systematic Review.

PURPOSE: Protrusion of the appendix within an inguinal hernia is termed an Amyand's hernia. A systematic review of case reports and case series of Amyand's hernia was performed, with emphasis on surgical decision-making. METHODS: The English literature (2000-2019) was reviewed, using PubMed and Embase, combining the terms "hernia", "inguinal", "appendix", "appendicitis" and "Amyand". Overall, 231 studies were included, describing 442 patients. RESULTS: Mean age of patients was 34 ± 32 years (adults 57.5%, children 42.5%). 91% were males, while a left-sided Amyand's hernia was observed in 9.5%. Of 156 elective hernia repairs, 38.5% underwent appendectomy and 61.5% simple reduction of the appendix. 88% of the adult patients had a mesh repair, without complications. Of 281 acute cases, hernial complications (76%) and acute appendicitis (12%) were the most common preoperative surgical indications. Appendectomy was performed in 79%, more extensive operations in 8% and simple reduction in 13% of cases. A mesh was used in 19% of adult patients following any type of resection and in 81% following reduction of the appendix. Among acute cases, mortality was 1.8% and morbidity 9.2%. Surgical site infections were observed in 3.6%, all of which in patients without mesh implantation. CONCLUSION: In elective Amyand's hernia cases, appendectomy may be considered in certain patients, provided faecal spillage is avoided, to prevent mesh infection. In cases of appendicitis, prosthetic mesh may be used, if the surgical field is relatively clean, whereas endogenous tissue repairs are preferred in cases of heavy contamination.

Unfinished Business: A Systematic Review of Stump Appendicitis.

BACKGROUND: Stump appendicitis is defined as interval inflammation of any residual appendicular tissue, after an appendicectomy. We present a systematic review of case series and case reports on stump appendicitis, emphasising on risk factors, diagnosis and surgical management. METHODS: The English literature (1945-2018) was reviewed, using PubMed, Embase and GoogleScholar, combining the terms "appendix", "appendicitis", "stump", "residual", "recurrent" and "retained". In total, 127 studies were included, describing 164 patients (males 59%, mean age 36 ± 17 years). RESULTS: Index surgery was open in 59% and laparoscopic in 38%. It was described as "difficult" or "complicated" in 31%. 20% of patients reported episodes of recurrent abdominal pain during the time interval between index and stump appendicitis (range 2 weeks to 60 years, median 2 years). Right lower quadrant pain was the most frequent complain (88%), leukocytosis was found in 56%, whereas 92% of patients underwent imaging testing, which was diagnostic or highly suspicious in 67.5%. Mean delay between beginning of symptoms and surgery was 2.4 ± 2.3 days. The operative approach was open in 61% and laparoscopic in 35% of cases. The operation was characterised as "difficult" or "complicated" in 45%. In the majority (88%), a completion stump appendicectomy was performed, with 11% requiring more extensive procedures. Mean length of resected stump was 3.1 ± 1.6 cm (range 0.5-10 cm). CONCLUSIONS: Stump appendicitis may occur following both open and laparoscopic approach, when the residual stump is > 0.5 cm. Its clinical significance lies in the delayed diagnosis, leading to higher incidence of complications and the need for more extensive surgery.

Ten-year Audit of Safe Bail-Out Alternatives to the Critical View of Safety in Laparoscopic Cholecystectomy.

BACKGROUND: To prevent vasculobiliary injuries according to the Tokyo Guidelines, Critical View of Safety (CVS) is the recommended method for the identification of the cystic duct and cystic artery. Our aim was to audit laparoscopic cholecystectomies, in order to determine the rate of CVS feasibility and to explore safe bail-out alternatives, when CVS cannot be obtained. METHODS: Patients who underwent either elective or emergent laparoscopic cholecystectomy, between January 2009 and December 2018, in whom the CVS was attempted, were retrospectively identified from the institutional electronic database. Dissection technique was documented in the operative notes. Bile duct injuries (BDI) were classified by the Strasberg classification, and their management and outcome were reported in the patient files. RESULTS: In total, 1226 cases were included in the final analysis. CVS was feasible in 1128 cases (92.0%), whereas 65 patients (5.3%) were managed laparoscopically by a bail-out technique. Of those, 52 (4.3%) underwent a subtotal cholecystectomy, 12 (0.9%) a fundus-first cholecystectomy, and in one patient (0.1%) the operation was concluded by a tube cholecystostomy. Overall conversion rate was 2.7% (33/1226 cases). Male gender, older age, junior surgeons, and acute cholecystitis were significantly associated with higher conversion rates. Post-operatively, 10 patients (0.82%) developed a type A bile leakage. No major BDI (types B-E) were observed, either with CVS or the bail-out techniques. CONCLUSIONS: Our study showed that CVS and the bail-out alternatives complement each other in preventing major BDI and should belong to the armamentarium of every modern surgeon.

Oxidation of bisphenol A in water by heat-activated persulfate.

The heat-activated persulfate oxidation of bisphenol A (BPA), a representative endocrine disrupting compound, was investigated with respect to the effect of several process variables on degradation rates. The activation temperature appears to be the single most important parameter, i.e. a temperature increase from 40 to 70 °C results in an 80-fold rate increase. Regarding initial BPA concentration, the reaction follows a pseudo-first order rate expression, where the kinetic constant decreases from 11.5 10-2 to 3.5 10-2 min-1 when BPA concentration increases from 110 to 440 µg/L. Reactions in actual water matrices, such as bottled water and secondary treated wastewater, are slower than in pure water since various organic/inorganic water constituents compete with BPA for being oxidized by the reactive oxidizing species; this was confirmed with experiments in pure water spiked with humic acid or bicarbonate. Interestingly though, the presence of chloride seems to promote BPA degradation. Furthermore, degradation is favored at near-neutral pH and increased sodium persulfate (SPS) concentrations. Experiments at an increased BPA concentration of 20 mg/L were performed to identify transformation by-products (TBPs), as well as assess the mineralization and toxicity of the treated samples. Liquid chromatography time-of-flight mass spectrometry (LC-TOF-MS) revealed the formation of eleven TBPs of BPA and plausible pathways including hydroxylation, oxidation, cleavage and oligomerization reactions are proposed. Mineralization occurs slower than BPA degradation, while the toxicity to marine bacteria Vibrio fischeri increases during the early stages of the reaction but it progressively decreases thereafter.

Boron-doped diamond oxidation of amoxicillin pharmaceutical formulation: Statistical evaluation of operating parameters, reaction pathways and antibacterial activity.

The electrochemical oxidation of a commercial amoxicillin formulation over a boron-doped diamond (BDD) anode was investigated. The effect of initial COD concentration (1-2 g/L), current density (30-50 mA/cm2), treatment time (15-90 min), initial pH (3-9) and electrolyte concentration (2-4 g/L NaCl) on COD removal was assessed through a factorial design methodology. For the range of conditions in question, the first three single effects, as well as the interaction between COD and time were the most important ones in terms of mass of COD removed. Liquid chromatography time-of-flight mass spectrometry (LC-TOF-MS) was employed to identify major transformation by-products (TBPs); thirteen compounds were detected as TBPs of AMX electrochemical degradation, while several others appear in the original formulation. AMX degradation occurs though the following pathways: (i) hydroxylation mainly in the benzoic ring, (ii) opening of ß-lactam ring followed by decarboxylation, hydroxylation and re-arrangement, and (iii) bond cleavage between the carbons of amino and amide groups. Furthermore, the process is accompanied by the release of several ions, i.e. nitrate, sulfate and ammonium. The antibiotic activity of AMX up to 1000 mg/L was tested against Klebsiella pneumoniae and Enterococcus faecalis reference strains; both bacteria are completely inactivated at this concentration but the activity is reduced substantially at lower concentrations. Oxidized samples still exhibit some antibacterial activity (50-60%) which is due to TBPs and active chlorine species present in the liquid phase. The latter are generated from chloride ions and enhance considerably AMX degradation rates.

Boron-doped diamond electrooxidation of ethyl paraben: The effect of electrolyte on by-products distribution and mechanisms.

Ethyl paraben (EP), a representative emerging pollutant of the parabens family, was subject to electrochemical oxidation over a boron-doped diamond (BDD) anode. Experiments were carried out in a single-compartment cell at 10-70 mA cm-2 current density, 200-600 µg L-1 EP concentration, initial solution pH 3-9 and 0.1 M electrolyte concentration. The degradation rate is favored at increased current densities and in the presence of NaCl as the supporting electrolyte, while the pH effect is inconsiderable. For instance, the first order rate constant for the degradation of 200 µg L-1 EP at 30 mA cm-2 was 0.25, 0.1 and 0.07 min-1 with NaCl, Na2SO4 and HClO4, respectively. Degradation in secondary treated wastewater was faster than in pure water presumably due to the action of chloride ions present in the effluent. Liquid chromatography time-of-flight mass spectrometry (LC-TOF-MS) was employed to determine major transformation by-products (TBPs). The route of EP degradation with Na2SO4 involves hydroxylation and demethylation reactions, signifying the role of electrogenerated hydroxyl radicals in the process. Twenty one TBPs were identified with NaCl as the electrolyte, including several chlorinated and non-chlorinated dimers and trimers; these findings suggest that indirect oxidation mediated by chlorine radicals and other chlorine active species also takes place. In this view, the role of the supporting electrolyte is crucial since it can influence both reaction kinetics and pathways.

Removal of antibiotics in a parallel-plate thin-film-photocatalytic reactor: Process modeling and evolution of transformation by-products and toxicity.

Photocatalytic degradation of sulfamethoxazole (SMX) antibiotic has been studied under recycling batch and homogeneous flow conditions in a thin-film coated immobilized system namely parallel-plate (PPL) reactor. Experimentally designed, statistically evaluated with a factorial design (FD) approach with intent to provide a mathematical model takes into account the parameters influencing process performance. Initial antibiotic concentration, UV energy level, irradiated surface area, water matrix (ultrapure and secondary treated wastewater) and time, were defined as model parameters. A full of 25 experimental design was consisted of 32 random experiments. PPL reactor test experiments were carried out in order to set boundary levels for hydraulic, volumetric and defined defined process parameters. TTIP based thin-film with polyethylene glycol+TiO2 additives were fabricated according to pre-described methodology. Antibiotic degradation was monitored by High Performance Liquid Chromatography analysis while the degradation products were specified by LC-TOF-MS analysis. Acute toxicity of untreated and treated SMX solutions was tested by standard Daphnia magna method. Based on the obtained mathematical model, the response of the immobilized PC system is described with a polynomial equation. The statistically significant positive effects are initial SMX concentration, process time and the combined effect of both, while combined effect of water matrix and irradiated surface area displays an adverse effect on the rate of antibiotic degradation by photocatalytic oxidation. Process efficiency and the validity of the acquired mathematical model was also verified for levofloxacin and cefaclor antibiotics. Immobilized PC degradation in PPL reactor configuration was found capable of providing reduced effluent toxicity by simultaneous degradation of SMX parent compound and TBPs.

A Multidisciplinary Assessment of River Surface Water Quality in Areas Heavily Influenced by Human Activities.

The present study could serve as a multidisciplinary approach for the assessment of river surface water quality with the use of chemical and biological methods. Specifically, physicochemical parameters, heavy metals, and pesticides were measured in water samples from three different stations (sampling station S1, S2, and S3) along Asopos River (Greece). In parallel, algal species (primary producers)-such as Scenedesmus rubescens and Chlorococcum sp.; consumer invertebrate species, such as the fairy shrimp Thamnocephalus platyurus and the rotifer Brachionus calyciflorus; as well as human lymphocytes-were exposed to those samples for assessing their toxic and genotoxic/mutagenic effects. According to the results, although the values of almost all of the physicochemical parameters tested, heavy metals (zinc, cadmium, lead, and mercury) and pesticides were lower than or within the respective environmental quality standards, thus offering no clear evidence for their natural or anthropogenic origin. Values recorded for nickel, chromium, hexavalent chromium, and malathion represent a typical case of mixed influence from natural and anthropogenic enrichments. In contrast, the algal growth arrest, the acute toxic effects on the freshwater invertebrates, and the increased micronuclei frequencies observed in human lymphocytes showed the presence of human-derived hazardous substances, which were hardly determinable with the use of conventional chemical methods. Given that the presence of priority pollutants in river surface waters, heavily burdened by anthropogenic activities, could give no clear evidence for their biological risk, the results of the present study showed that chemical and biological assays should be applied in parallel, thus serving as a reliable tool for the assessment of river water quality.

Enhanced synthesis of multiblock copolymers via acid-triggered RAFT polymerization.

The synthesis of multiblock copolymers has emerged as an efficient tool to not only reveal the optimal way to access complex structures and investigate polymer properties but also to ascertain the end-group fidelity of a given polymerization methodology. Although reversible addition-fragmentation chain-transfer (RAFT) polymerization is arguably the most dominant strategy employed, its success is often hampered by the unavoidable and excessive use of radical initiators which results in increased termination and loss of end-group fidelity. In this work, we employ acid in RAFT polymerization to enhance the synthesis of multiblock copolymers. By the addition of a small amount of acid, a 4-fold decrease in the overall required radical initiator concentration was achieved, enabling the synthesis of a range of well-defined multiblock copolymers with various degrees of polymerization (DP) per block. The acid enhances the propagation rate, minimizing the initiator concentration. In all cases, near-quantitative monomer conversion was obtained (>97%) for every iterative block formation step. Notably, and in contrast to conventional RAFT approaches, the tailing to low molecular weight was significantly suppressed and the dispersity was maintained nearly constant (i.e. in most cases D = 1.1-1.2), thus indicating minor termination events and side reactions during acid-enhanced synthesis. The possibility to synthesize multiblocks consisting of methacrylates, acrylates, and acrylamides was also demonstrated. This work presents an advancement in the synthesis of well-defined multiblock copolymers and more broadly, RAFT polymers with high end-group fidelity.

Current state of knowledge of environmental occurrence, toxic effects, and advanced treatment of PFOS and PFOA.

Per- and polyfluoroalkyl substances (PFAS) are anthropogenic synthetic compounds, with high chemical and thermal stability and a persistent, stable and bioaccumulative nature that renders them a potential hazard for the environment, its organisms, and humans alike. Perfluorooctane sulfonic acid (PFOS) and Perfluorooctanoic acid (PFOA) are the most well-known substances of this category and even though they are phased out from production they are still highly detectable in several environmental matrices. As a result, they have been spread globally in water sources, soil and biota exerting toxic and detrimental effects. Therefore, up and coming technologies, namely advanced oxidation processes (AOPs) and advanced reduction processes (ARPs) are being tested for their implementation in the degradation of these pollutants. Thus, the present review compiles the current knowledge on the occurrence of PFOS and PFOA in the environment, the various toxic effects they have induced in different organisms as well as the ability of AOPs and ARPs to diminish and/or eliminate them from the environment.

Sonocatalytic degradation of Bisphenol A from aquatic matrices over Pd/CeO2 nanoparticles: Kinetics study, transformation products, and toxicity.

In this work, different ratios of palladium - cerium oxide (Pd/CeO2) catalyst were synthesized and characterized, while their sonocatalytic activity was evaluated for the degradation of the xenobiotic Bisphenol A (BPA) from aqueous solutions. Sonocatalytic activity expressed as BPA decomposition exhibited a volcano-type behavior in relation to the Pd loading, and the 0.25Pd/CeO2 catalyst characterized by the maximum Pd dispersion and lower crystallite size demonstrated the higher activity. Using 500 mg/L of 0.25 % Pd/CeO2 increased the kinetic constant for BPA destruction by more than two times compared to sonolysis alone (20 kHz at 71 W/L). Meanwhile, the simultaneous use of ultrasound and a catalyst enhanced the efficiency by 50.1 % compared to the sum of the individual processes, resulting in 95 % BPA degradation in 60 min. The sonocatalytic degradation of BPA followed pseudo-first-order kinetics, and the apparent kinetic constant was increased with ultrasound power and catalyst loading, while the efficiency was decreased in bottled water and secondary effluent. From the experiments that were conducted using appropriate scavengers, it was revealed that the degradation mainly occurred on the bubble/liquid interface of the formed cavities, while the reactive species produced from the thermal or light excitation of the prepared semiconductor also participated in the reaction. Five first-stage and four late-stage transformation products were identified using UHPLC/TOF-MS, and a pathway for the sonocatalytic degradation of BPA was proposed. According to ECOSAR software prediction, most transformation by-products (TBPs) present lower ecotoxicity than the parent compound, although some remain toxic to the indicators chosen.

Chemical recycling of bromine-terminated polymers synthesized by ATRP.

Chemical recycling of polymers is one of the biggest challenges in materials science. Recently, remarkable achievements have been made by utilizing polymers prepared by controlled radical polymerization to trigger low-temperature depolymerization. However, in the case of atom transfer radical polymerization (ATRP), depolymerization has nearly exclusively focused on chlorine-terminated polymers, even though the overwhelming majority of polymeric materials synthesized with this method possess a bromine end-group. Herein, we report an efficient depolymerization strategy for bromine-terminated polymethacrylates which employs an inexpensive and environmentally friendly iron catalyst (FeBr2/L). The effect of various solvents and the concentration of metal salt and ligand on the depolymerization are judiciously explored and optimized, allowing for a depolymerization efficiency of up to 86% to be achieved in just 3 minutes. Notably, the versatility of this depolymerization is exemplified by its compatibility with chlorinated and non-chlorinated solvents, and both Fe(ii) and Fe(iii) salts. This work significantly expands the scope of ATRP materials compatible with depolymerization and creates many future opportunities in applications where the depolymerization of bromine-terminated polymers is desired.