The hurdle effect of osmotic pretreatment and high‐pressure cold pasteurisation on the shelf‐life extension of fresh‐cut tomatoes

Tomatoes are perishable products due to the activity of microorganisms and endogenous enzymes. The objective was to produce cut tomatoes with extended shelf life, using the combined hurdle effect of osmotic pretreatment (OD) and high pressure (HP), instead of a conventional one‐step thermal process. Samples were processed in a multicomponent osmotic solution at 35 °C, subsequently cold‐pasteurised in pack at 600 MPa and stored at 5–15 °C. Quality deterioration during isothermal and nonisothermal storage was kinetically modelled. Both OD process and OD‐HP combined process caused an increase in lycopene content that was well retained. Texture, colour and flavour of treated samples were evaluated as similar to fresh, with OD‐HP samples showing better retention during storage. Being microbiologically stable, shelf life of OD‐HP samples was limited by sensory deterioration, whereas OD samples were rejected due to eventual microbial growth. Shelf life of OD and OD‐HP samples was estimated at 77 and 181 days, respectively, at 5 °C.     

Local Accumulation of Lymphocytes in the Intima of Human Aorta Is Associated with Giant Multinucleated Endothelial Cells: Possible Explanation for Mosaicism of Atherosclerosis

Distribution of different types of atherosclerotic lesions in the arterial wall is not diffuse, but is characterized by mosaicism. The causes of such distribution remain to be established. At the early stages of atherogenesis, low-density lipoprotein (LDL) particles and immune cells penetrate into the intimal layer of the arterial wall through the endothelium. In adult humans, the luminal surface of the arterial wall is a heterogeneous monolayer of cells with varying morphology including typical endothelial cells (ECs) and multinucleated variant endothelial cells (MVECs). We hypothesized that distribution of MVECs in the endothelial monolayer can be related to the distribution pattern of early atherosclerotic lesions. We obtained en face preparations of intact adult (22–59 years old) aortic wall sections that allowed us to study the endothelial monolayer and the subendothelial layer. We compared the distribution of MVECs in the endothelial monolayer with the localization of early atherosclerotic lesions in the subendothelial layer, which were characterized by lipid accumulation and immune cell recruitment. In primary culture, MVECs demonstrated increased phagocytic activity compared to mononuclear ECs. Moreover, we have shown that unaffected aortic intima contained associates formed as a result of aggregation and/or fusion of LDL particles that are non-randomly distributed. This indicated that MVECs may be involved in the accumulation of LDL in the subendothelial layer through increased transcytosis. Interaction of LDL with subendothelial cells of human aorta in primary culture increased their adhesive properties toward circulating immune cells. Study of unaffected aortic intima revealed non-random distribution of leukocytes in the subendothelial layer and increased localization of CD45+ leukocytes in the subendothelial layer adjacent to MVECs. Together, our observations indicate that MVECs may be responsible for the distribution of atherosclerotic lesions in the arterial wall by participating in LDL internalization and immune cell recruitment.     

Protection of bronze covered with patina by innoxious organic substances

Cultural bronze artefacts are exposed in indoor or outdoor environment. They often suffer of a substantial alteration due to an increasing atmospheric pollution. In this work, we propose the use of some innoxious compounds as corrosion inhibitors of bronze objects covered with patina. The bronze used was Cu-6Sn (in wt.%). This composition was selected after a preliminary work on several archaeological bronzes found in Transylvania, Romania, dated from the Late Neolithic to Roman periods. First, an artificial patina was formed on Cu-6Sn bronze under potential regulation, in 0.2 g L⁻¹ NaHCO₃ + 0.2 g L⁻¹ Na₂SO₄ aqueous solution (pH 8), during 4 days. A pale blue to green patina was obtained and characterized using EDS and Raman spectroscopy. Then, four innoxious organic substances were examined as corrosion inhibitors: 5 mM 4-methyl-1-(p-tolyl)-imidazole (TMI), 10 mM 1-phenyl 4-methyl-imidazole (PMI), 1 mM 2-mercapto 5-R-acetylamino-1,3,4-thiadiazole (MAcT), 1 mM 2-mercapto 5-R-amino-1,3,4-thiadiazole (MAT), and for comparison 1 mM benzotriazole (BTA). The impedance spectra collected showed, for all of them, three depressed capacitive loops. On the basis of these capacitance values, these loops were allocated to the surface film with ionic conduction, the double layer capacitance with the charge transfer resistance, and the oxidation-reduction process involving the surface patina. TMI and MAcT were found to be efficient inhibitors though their performances are significantly lower than that of BTA.     

Direct Staudinger–Phosphonite Reaction Provides Methylphosphonamidates as Inhibitors of CE4 De‐N‐acetylases

De‐N‐acetylases of β‐(1→6)‐D ‐N‐acetylglucosamine polymers (PNAG) and β‐(1→4)‐D ‐N‐acetylglucosamine residues in peptidoglycan are attractive targets for antimicrobial agents. PNAG de‐N‐acetylases are necessary for biofilm formation in numerous pathogenic bacteria. Peptidoglycan de‐N‐acetylation facilitates bacterial evasion of innate immune defenses. To target these enzymes, transition‐state analogue inhibitors containing a methylphosphonamidate have been synthesized through a direct Staudinger–phosphonite reaction. The inhibitors were tested on purified PgaB, a PNAG de‐N‐acetylase from Escherichia coli, and PgdA, a peptidoglycan de‐N‐acetylase from Streptococcus pneumonia. Herein, we describe the most potent inhibitor of peptidoglycan de‐N‐acetylases reported to date (K_i=80 μM ). The minimal inhibition of PgaB observed provides insight into key structural and functional differences in these enzymes that will need to be considered during the development of future inhibitors.     

Seismic displacements of landfills and deformation of geosynthetics due to base sliding

Seismic design of waste landfills has been a subject of intense research over the past two decades, primarily due to the severe environmental impact of a potential failure. The majority of the related studies have been focused on the stability assessment of landfills utilizing permanent deformation methods. However, previous investigations have not fully addressed the impact of the composite liner system on the seismic performance of the geostructure, mainly expressed as potential sliding development, which is greatly affected by the geometry and the resulting initial static stress state of the landfill. Therefore, the aforementioned issues are investigated via a detailed parametric study, where the dynamic behaviour of the composite liner system is examined both analytically and numerically. The conducted coupled analyses indicated that the most significant parameters of the complex dynamic response of waste landfills can be reduced in two ratios that comprise functions of the main characteristics of the geostructure and of the excitation. Moreover, two distinct failure patterns have been identified with respect to the characteristics of the distribution of the permanent displacements along the interface and the axial deformation along the geosynthetic. The occurrence conditions of these failure patterns can be determined in terms of the two abovementioned ratios as verified by the analytical results of the critical acceleration of a simple SDOF system.     

Corrosion behavior of Cu–SiO<Subscript>2</Subscript> nanocomposite coatings obtained by electrodeposition in the presence of cetyl trimethyl ammonium bromide

Copper silica composite coatings are an attractive alternative to chromium and nickel coatings in order to avoid environmental problems and for application in electrical devices. However, co-deposition of SiO₂ particles with metals occurs to a rather limited extent, generally under 1%, due to the hydrophilicity of SiO₂, which makes the incorporation of particles in a metallic matrix difficult. To overcome this drawback, the influence of cetyl trimethyl ammonium bromide (CTAB) on the deposition and corrosion behavior of Cu–SiO₂ coatings on steel has been studied. It was established that CTAB plays a beneficial role in SiO₂ suspension stabilization, promotes the co-deposition of nanoparticles in the copper matrix and improves the deposit morphology and structure. Consequently, a higher corrosion resistance of Cu–SiO₂ deposits obtained in the presence of CTAB was noticed. The most important effect was observed in the case when CTAB was used in concentration of 10⁻³ M in the electroplating bath.     

Gradient-based Pareto front approximation applied to turbomachinery shape optimization

Engineering with Computers - Multi-objective optimization has been rising in popularity, especially within an industrial environment, where several cost functions often need to be considered during...     

Aerodynamic optimization using a parallel asynchronous evolutionary algorithm controlled by strongly interacting demes

A parallel asynchronous evolutionary algorithm controlled by strongly interacting demes for single- and multi-objective optimization problems is proposed. It is suitable even for non-homogeneous, multiprocessor systems, ensuring maximum exploitation of the available processors. The search algorithm utilizes a structured topology of evaluation agents organized in a number of inter-communicating demes arranged on a 2D supporting mesh. Once an evaluation terminates and a processor becomes idle, a series of intra- and inter-deme processes determines the next agent to undergo evaluation on this specific processor. Real coding and differential evolution operators are used. Mathematical and aerodynamic-turbomachinery optimization problems are presented to assess the proposed method in terms of CPU cost, parallel efficiency and quality of solutions obtained within a predefined number of evaluations. Comparisons with conventional evolutionary algorithms, parallelized based on the master–slave model on the same computational platform, are presented.     

A contaminant trap as a tool for isolating and measuring the desorption resistant fraction of soil pollutants

Bioremediation of contaminated soils often leaves a desorption-resistant pollutant fraction behind in the soil, which in the present study was isolated with a combination of diffusive carrier and infinite diffusive sink. Such a diffusive sink was made by casting a composite of silicone and activated carbon into the bottom of a large glass. Field-contaminated soil samples were then suspended in a cyclodextrin solution and incubated in such glasses for the continuous trapping of PAH molecules during their release from the soil matrix. The PAH concentrations remaining in the soil were determined by exhaustive extraction and compared with a biodegradation experiment. The concentration decline in the first soil was faster in the contaminant trap than in the biodegradation experiment, but the halting of the biodegradation process before reaching the legal threshold level was well indicated by the contaminant trap. The PAH concentrations in the second soil hardly decreased in the traps at all, in good agreement with the biodegradation experiment. The PAHs in this soil appeared to be "stuck" by strong sorption. The contaminant trap proved to be a practical approach to the isolation and quantification of the desorption-resistant PAH fraction.