Statistical Evaluation of Factors Affecting the Leaching Process of Waste Electrical and Electronic Equipment using Sodium Persulfate

Recycling of waste electrical and electronic equipment (WEEE) is important not only to reduce the amount of waste requiring treatment, but also to promote the recovery of valuable materials. Implementation of the European Directive on WEEE and recycling targets imposed in the European Union will require new processes to be developed and applied to recover metals from WEEE. This study aims to provide an alternative process for the dissolution of metals from WEEE which contains Cu and Zn based on our previous research. The effects of leaching parameters, such as temperature, Na₂S₂O₈ concentration, and leaching time, were separately investigated on leaching of copper, zinc, and brass (alloy composition ?35% zinc and 65% copper) in Na₂S₂O₈ solution (0.1, 0.2 and 0.3 M). Box–Behnken experimental design (BBD) method was used to determine the number and the condition of necessary leaching experiments. Statistical analysis of variance (ANOVA) was performed to see whether process parameters such as leaching time, temperature, and oxidant concentration are statistically significant or not on the leaching performance. Results show leaching time as the most influential factor in the dissolution process, for the first six models. Two extended models have been developed to optimize the parameters of the investigated process. In these models, we consider the metal composition as a model input next to the earlier investigated parameters. Optimal condition for maximum copper and zinc dissolution in Na₂S₂O₈ environment can be found for parameter values: temperature 45°C, oxidant concentration 0.1 M and leaching time 35 min.     

Identification of desulphoglucosinolates in Brassicaceae by LC/MS/MS: comparison of ESI and atmospheric pressure chemical ionisation-MS

In order to develop a sensitive method for the detection of desulphoglucosinolates by HPLC-MS, the two most common interfaces for HPLC-MS, atmospheric pressure chemical ionisation (APCI) and ESI, were compared. While working with the APCI-interface the evaporation temperature and corona amperage were optimised. In doing so 300 degrees C and 6 muA proved to be most suitable for aliphatic and indole desulphoglucosinolates. The use of formic acid instead of water in the eluent in HPLC-ESI-MS measurements increased the sensitivity for the indole desulphoglucosinolates in the presence of 1 mM formic acid, while the sensitivity for the aliphatic desulphoglucosinolate desulphoglucoraphanin was substantially increased by the presence of 5 mM formic acid. Using an Agilent ion trap, two optimisation procedures for the MS parameters, smart and expert mode, were available. In smart mode the software optimises several parameters automatically, which is much more time efficient than expert mode, in which the optimisation is done manually. It turned out that ESI-MS is most sensitive in smart mode, while for APCI-MS a higher sensitivity could be gained using the expert mode. Comparing both interfaces, APCI-MS was more sensitive than ESI-MS. However, no additional information, in terms of structure determination, was obtained by APCI-MS.     

Cardiac Telocytes 16 Years on—What Have We Learned So Far,and How Close Are We to Routine Application of the Knowledge in Cardiovascular Regenerative Medicine?

The regeneration of a diseased heart is one of the principal challenges of modern cardiovascular medicine. There has been ongoing research on stem-cell-based therapeutic approaches. A cell population called telocytes (TCs) described only 16 years ago largely contributed to the research area of cardiovascular regeneration. TCs are cells with small bodies and extremely long cytoplasmic projections called telopodes, described in all layers of the heart wall. Their functions include cell-to-cell signaling, stem-cell nursing, mechanical support, and immunoregulation, to name but a few. The functional derangement or quantitative loss of TCs has been implicated in the pathogenesis of myocardial infarction, heart failure, arrhythmias, and many other conditions. The exact pathomechanisms are still unknown, but the loss of regulative, integrative, and nursing functions of TCs may provide important clues. Therefore, a viable avenue in the future modern management of these conditions is TC-based cell therapy. TCs have been previously transplanted into a mouse model of myocardial infarction with promising results. Tandem transplantation with stem cells may provide additional benefit; however, many underresearched areas need to be addressed in future research before routine application of TC-based cell therapy in human subjects. These include the standardization of protocols for isolation, cultivation, and transplantation, quantitative optimization of TC transplants, cost-effectivity analysis, and many others.     

Isolation,Culture and Comprehensive Characterization of Biological Properties of Human Urine-Derived Stem Cells

Mesenchymal stem cells (MSCs) represent an attractive source within the field of tissue engineering. However, their harvesting often requires invasive medical procedures. Urine-derived stem cells (UDSCs) display similar properties to MSCs, and their obtention and further processing is non-invasive for the donors as well as low cost. Here, we offer a comprehensive analysis of their biological properties. The goal of this study was to analyze their morphology, stemness, differentiation potential and cytokine profile. We have successfully isolated UDSCs from 25 urine samples. First colonies emerged up to 9 days after the initial seeding. Cell doubling time was 45 ± 0.24 SD, and when seeded at the density of 100 cells/cm², they formed 42 ± 6.5 SD colonies within 10 days. Morphological analyzes revealed that two different types of the cell populations have been present. The first type had a rice-grain shape and the second one was characterized by a polyhedral shape. In several cell cultures, dome-shaped cells were observed as well. All examined UDSCs expressed typical MSC-like surface markers, CD73, CD90 and CD105. Moreover, conditioned media from UDSCs were harvested, and cytokine profile has been evaluated showing a significantly higher secretory rate of IL-8, IL-6 and chemokines MCP-1 and GM-CSF. We have also successfully induced human UDSCs into chondrogenic, osteogenic and myogenic cell lineages. Our findings indicate that UDSCs might have immense potential in the regeneration of the damaged tissues.     

Controlled descent training

In this work, a novel and model-based artificial neural network (ANN) training method is developed supported by optimal control theory. The method augments training labels in order to robustly guarantee training loss convergence and improve training convergence rate. Dynamic label augmentation is proposed within the framework of gradient descent training where the convergence of training loss is controlled. First, we capture the training behavior with the help of empirical Neural Tangent Kernels (NTK) and borrow tools from systems and control theory to analyze both the local and global training dynamics (e.g., stability, reachability). Second, we propose to dynamically alter the gradient descent training mechanism via fictitious labels as control inputs and an optimal state feedback policy. In this way, we enforce locally $$ optimal and convergent training behavior. The novel algorithm, Controlled Descent Training (CDT), guarantees local convergence. CDT unleashes new potentials in the analysis, interpretation, and design of ANN architectures. The applicability of the method is demonstrated on standard regression and classification problems.     

Comparison of the fracture and failure behavior of injection-molded α- and β-polypropylene in high-speed three-point bending tests

The fracture and failure mode of α- and β-isotactic polypropylene (α-iPP and β-iPP, respectively) were studied in high speed (1 m/s) three-point bending tests on notched bars cut from injection-molded dumbbell specimens and compared. The fracture response of the notched Charpy-type specimens at room temperature (RT) and −40°C, respectively, was described by terms of the linear elastic fracture mechanics (LEFM), namely fracture toughness (K_c) and fracture energy (G_c). K_c values of both iPP modifications were similar, while G_c values of the β-iPP were approximately twofold of the reference α-iPP irrespective of the test temperature. It was demonstrated that β-iPP failed in a ductile and brittle-microductile manner at RT and −40°C, respectively. By contrast, brittle fracture dominated in α-iPP at both testing temperatures. Based on the fracture surface appearance, it was supposed that β-to-α (βα) transformation occurred in β-iPP. The superior fracture energy of β-iPP to α-iPP was attributed to a combined effect of the following terms: morphology, mechanical damping, and phase transformation. Results indicate that their relative contribution is a function of the test temperature. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 64: 2057–2066, 1997     

Occurrence of pyrrolizidine alkaloids in animal- and plant-derived food: results of a survey across Europe

Pyrrolizidine alkaloids (PAs) are secondary metabolites of plant families such as Asteraceae or Boraginaceae and are suspected to be genotoxic carcinogens. Recent investigations revealed their frequent occurrence in honey and particularly in tea. To obtain a comprehensive overview of the PA content in animal- and plant-derived food from the European market, and to provide a basis for future risk analysis, a total of 1105 samples were collected in 2014 and 2015. These comprised milk and milk products, eggs, meat and meat products, (herbal) teas, and (herbal) food supplements collected in supermarkets, retail shops, and via the internet. PAs were detected in a large proportion of plant-derived foods: 91% of the (herbal) teas and 60% of the food supplements contained at least one individual PA. All types of (herbal) teas investigated were found to contain PAs, with a mean concentration of 460 µg kg^?1 dry tea (corresponding to 6.13 µg L^?1 in [herbal] tea infusion). The highest mean concentrations were found in rooibos tea (599 µg kg^?1 dry tea, 7.99 µg L^?1 tea infusion) and the lowest in camomile tea (274 µg kg^?1 dry tea, 3.65 µg L^?1 tea infusion). Occurrence of PAs in food supplements was found to be highly variable, but in comparable ranges as for (herbal) tea. The highest concentrations were present in supplements containing plant material from known PA-producing plants. In contrast, only 2% of the animal-derived products, in particular 6% of milk samples and 1% of egg samples, contained PAs. Determined levels in milk were relatively low, ranged between 0.05 and 0.17 µg L^?1 and only trace amounts of 0.10–0.12 µg kg^?1 were found in eggs. No PAs were detected in the other animal-derived products.     

Evolution of Volatile Flavor Compounds During Roasting of Nut Seeds by Thermogravimetry Coupled to Fast-Cycling Optical Heating Gas Chromatography-Mass Spectrometry with Electron and Photoionization

Online multidimensional evolved gas analysis was conducted during the roasting of nuts using fast-cycling optical heating gas chromatography (OHGC) coupled to mass spectrometry with electron ionization and soft single photon ionization (OHGC-EI/SPI-MS). SPI is a semi-selective soft ionization method for organic compounds that produces mainly molecular ions, whereas EI is a hard ionization method that results in fragmentation. Ionization was either done exclusively by one of these methods or both were used alternately. Roasting of the nuts (almonds, Brazil nuts, cashews, peanuts, hazelnuts, pecans, pine nuts, and walnuts) was simulated in a thermal analysis (TA) device at a roasting temperature of 170 °C. The TA device was directly coupled to the OHGC-EI/SPI-MS for quasi-real-time analysis. Multidimensional analysis was possible with a temporal resolution of 1 min. Good chromatographic separation, constant sampling repetition rates, and constant retention times (RTs) were obtained. Peak assignment was performed using the molecular mass information obtained from SPI-MS, the characteristic fragmentation patterns from EI-MS, and the OHGC RTs. The gases that evolved during roasting of each type of nut were monitored online using the TA-OHGC-MS setup. Aldehydes, furans, and pyrazines were detected as flavor compounds. Changes in the compositions of the evolved gases during the roasting process were evaluated. The TA-OHGC-MS method could separate isobaric and isomeric compounds.     

Molecular Network Approach Reveals Rictor as a Central Target of Cardiac ProtectomiRs

Cardioprotective medications are still unmet clinical needs. We have previously identified several cardioprotective microRNAs (termed ProtectomiRs), the mRNA targets of which may reveal new drug targets for cardioprotection. Here we aimed to identify key molecular targets of ProtectomiRs and confirm their association with cardioprotection in a translational pig model of acute myocardial infarction (AMI). By using a network theoretical approach, we identified 882 potential target genes of 18 previously identified protectomiRs. The Rictor gene was the most central and it was ranked first in the protectomiR-target mRNA molecular network with the highest node degree of 5. Therefore, Rictor and its targeting microRNAs were further validated in heart samples obtained from a translational pig model of AMI and cardioprotection induced by pre- or postconditioning. Three out of five Rictor-targeting pig homologue of rat ProtectomiRs showed significant upregulation in postconditioned but not in preconditioned pig hearts. Rictor was downregulated at the mRNA and protein level in ischemic postconditioning but not in ischemic preconditioning. This is the first demonstration that Rictor is the central molecular target of ProtectomiRs and that decreased Rictor expression may regulate ischemic postconditioning-, but not preconditioning-induced acute cardioprotection. We conclude that Rictor is a potential novel drug target for acute cardioprotection.