A Structure-Properties Relationship Study of Self-Healing Materials Based on Styrene and Furfuryl Methacrylate Cross-Linked via Diels–Alder Chemistry

A series of copolymers of styrene and furfuryl methacrylate characterized by various molecular structures (linear and star, block and random) is synthesized via atom transfer radical polymerization, and cross-linked with a bismaleimide by means of thermally reversible Diels–Alder (DA) reaction, to obtain self-healing materials. The prepared materials are studied in terms of gelation, swelling, thermal, and dynamic-mechanical analysis, with the aim of correlating relevant properties to their chemical structure. It is found that the furan/styrene ratio, as well as the molecular architecture, have a major influence on the properties. It is also found that the reversibility of the DA reaction is not complete in the solid state for materials with high cross-linking density. This study provides some important tools for the design of materials characterized by thermally reversible behavior, which find usually application as self-healing thermosets, coatings, or adhesives.     

Development and evaluation of alternative processes for sterilization and deodorization of cork barks and natural cork stoppers

Cork taint, one of the most known off-flavours in wine, is usually attributed to the presence of the aromatic compound 2,4,6-trichloroanisole (2,4,6-TCA) in cork stoppers made from the bark of the cork oak, Quercus suber. There are many major chemical/biochemical pathways through which 2,4,6-TCA can be formed during cork production. The estimated incidence of cork-tainted wine bottles ranges from 2–to 7%, costing global wine industry approximately US$ 10 billion annually. During this study, a laboratory-scale system was designed and constructed, to efficiently treat cork bark and stopper samples using ozone and/or other sterilizing gases, such as steam, via sequential application of pulsed vacuum–pressure cycles. The developed physicochemical processes were studied and evaluated in order to achieve both sterilization conditions and 2,4,6-TCA removal without affecting the mechanical and bottling properties of cork. According to the results, the application of ozone alone seems to be a promising treatment method for cork barks. However, the pulsed treatment ensures both sufficient removal (99%) of both bacteria and moulds from cork stoppers when combined with ozone or steam and satisfactory deodorization of cork stoppers achieving high percentages (90%) of 2,4,6-TCA removal when combined with steam. The operating cost of each alternative process (plain or pulsed, with or without ozone and/or steam) was estimated and compared, in laboratory scale, for the selection of the most efficient process, taking into account technicoeconomical aspects.     

Antibacterial Activity of Copper Nanoparticles against Xanthomonas campestris pv. vesicatoria in Tomato Plants

Copper-based bactericides have appeared as a new tool in crop protection and offer an effective solution to combat bacterial resistance. In this work, two copper nanoparticle products that were previously synthesized and evaluated against major bacterial and fungal pathogens were tested on their ability to control the bacterial spot disease of tomato. Growth of Xanthomonas campestris pv. vesicatoria, the causal agent of the disease, was significantly suppressed by both nanoparticles, which had superior function compared to conventional commercial formulations of copper. X-ray fluorescence spectrometry measurements in tomato leaves revealed that bioavailability of copper is superior in the case of nanoparticles compared to conventional formulations and is dependent on synthesis rather than size. This is the first report correlating bioavailability of copper to nanoparticle efficacy.     

A Green Route for the Preparation of Aliphatic Polyesters via Lipase‐catalyzed Prepolymerization and Low‐temperature Postpolymerization

Lipase‐catalyzed polycondensation of two biobased diacids, 1,12‐dodecanedioic acid and 1,14‐tetradecanedioic acid, with 1,8‐octanediol was achieved using immobilized Lipase B from Candida antarctica. The procedure resulted in partially renewable prepolymers, while poly(octylene adipate) from petroleum‐based adipic acid was also synthesized for comparison reasons, revealing a dependence of the enzymatic polymerization degree on monomer composition. The prepolymers were further submitted to bulk postpolymerization at temperatures in the vicinity of their melting point under flowing nitrogen. The intrinsic viscosity increase was found up to 12%, with no significant impact on the polyesters thermal properties.

     

The choice of governance mode in ICT alliances: A property rights approach

We employed a property rights approach to formulate a set of hypotheses explaining the choice between equity and non-equity alliances in the Information and Communication Technology industry. The firm's need to control knowledge exchange and the resulting innovation makes property rights an important concern permeating partners’ strategic behavior. We showed that equity alliances were preferred, when partners kept a competitive relationship and followed a diversification strategy. However, non-equity alliances were preferred, when partners exhibited high resource complementarity. Finally, our research indicated that, when alliances targeted innovation development, prior ties between partners positively affected the choice of equity alliances.     

Successful medical treatment of emphysematous pyelonephritis in chronic hemodialysis

Emphysematous pyelonephritis (EPN) is a life‐threatening renal infection caused by gas‐producing bacteria and fungi. It usually occurs in patients with diabetes and patients with urinary tract obstruction. A combination of systemic antibiotics, percutaneous catheter drainage, or open nephrectomy is typically required to achieve cure. Because of grim prognosis, resorting to interventional methods is frequently inevitable. We report the case of a 77‐year‐old woman with diabetes and end‐stage renal disease on chronic hemodialysis that presented with fever and left flank pain. A bubbly gas pattern inside the left kidney was demonstrated on abdominal computed tomography scan and blood cultures grew Escherichia coli. She was successfully treated solely with systemic antibiotics. This highlights the fact that prompt recognition of imaging findings associated with benign prognosis is essential for a favorable outcome. It allows for an effective management avoiding high‐risk interventions, especially in frail patients with multiple comorbidities. Finally, we review all published cases of EPN in chronic dialysis patients.     

Matrix effect during the application of a rapid method using HS-SPME followed by GC–ECD for the analysis of 2,4,6-TCA in wine and cork soaks

An off-flavor in wine known as ‘cork taint’ is of concern in the wine and cork industry. Cork taint imparts a musty flavor to the wine and is primarily due to the presence of 2,4,6-trichloroanisole [2,4,6-TCA] in cork stoppers. During this study, an instrumental method for 2,4,6-TCA analysis was developed and evaluated using headspace solid-phase microextraction (HS-SPME) and gas chromatography coupled with an electron capture detector (GC–ECD). 2,3,6-Trichlorotoluene [2,3,6-TCT] was assayed as the internal standard. The method was developed in synthetic wine and was applied in commercial wine samples, as well as in cork soaks obtained by the extraction of TCA from cork stoppers and cork barks using synthetic wine. The method performance was evaluated through the estimation of its linearity (R² > 0.99), repeatability (RSD value = 5.72%) and sensitivity (recovery > 86%, LOD = 0.177–0.368 ng/L) in different types of samples. Due to the complexity of the samples used, the study has been especially focused on the matrix effects that were identified causing significant bias to the quantitative analysis of 2,4,6-TCA in cork soaks, where there is a lack of previous studies.     

The impact of bromide on the formation of neutral and acidic disinfection by-products (DBPs) in Mediterranean chlorinated drinking water

By using the Grob closed loop stripping analysis technique a wide variety of disinfection by-products (DBPs) was determined, in finished drinking water of 15 important cities of Greece distributed in the southern, northern, west continental land and in the islands of Aegean and Ionian Seas. Trihalomethanes, haloacetonitriles, haloacetic acids, chloropicrin, halogenated ketons and chloral hydrate were the main DBPs determined. In chlorinated drinking water of coastal cities brominated DBPs were most abundant than their chlorinated homologues due to the higher bromide concentration in raw waters of these areas. Factor analysis with principal component extraction of the results demonstrated a clear differentiation between the examined drinking waters on the basis of their DBPs content and vicinity to the sea.