The effectiveness of adaptive versus non-adaptive learning with digital educational games

For the training of academic skills, digital educational games with integrated adaptivity are promising. Adaptive games are considered superior to non-adaptive games, because they constantly assess children's performance, and accordingly adapt the difficulty of the tasks corresponding to the children's individual level. However, empirical evidence with regard to the effectivity of adaptive compared to non-adaptive games is limited. A study was conducted with 191 children from the third year of Kinder garten who were enrolled in one of three conditions, that is, playing an adaptive version of the reading game (RG), a non-adaptive version of the RG or training with pen-and-paper exercises. In all three conditions, children trained emergent reading (phonological awareness and letter knowledge) once a week for 30 min over a period of 5 weeks. Children's performance on cognitive (phonological awareness, letter knowledge, reading fluency) and non-cognitive (motivation, self-concept) factors was assessed. Results revealed a significant improvement in phonological awareness and letter knowledge in all conditions. However, no differences between the conditions were observed with respect to children's improvement on phonological awareness and letter knowledge or on their post-test scores for reading fluency. With regard to motivation and self-concept, again, no differences in these non-cognitive factors were observed across conditions.     

Bona Fide Tumor Suppressor Genes Hypermethylated in Melanoma: A Narrative Review

Loss-of-function events in tumor suppressor genes (TSGs) contribute to the development and progression of cutaneous malignant melanoma (CMM). Epigenetic alterations are the major mechanisms of TSG inactivation, in particular, silencing by promoter CpG-island hypermethylation. TSGs are valuable tools in diagnosis and prognosis and, possibly, in future targeted therapy. The aim of this narrative review is to outline bona fide TSGs affected by promoter CpG-island hypermethylation and their functional role in the progression of CMM. We conducted a systematic literature review to identify studies providing evidence of bona fide TSGs by cell line or animal experiments. We performed a broad first search and a gene-specific second search, supplemented by reference checking. We included studies describing bona fide TSGs in CMM with promoter CpG-island hypermethylation in which inactivating mechanisms were reported. We extracted data about protein role, pathway, experiments conducted to meet the bona fide criteria and hallmarks of cancer acquired by TSG inactivation. A total of 24 studies were included, describing 24 bona fide TSGs silenced by promoter CpG-island hypermethylation in CMM. Their effect on cell proliferation, apoptosis, growth, senescence, angiogenesis, migration, invasion or metastasis is also described. These data give further insight into the role of TSGs in the progression of CMM.     

Liquid‐to‐solid ratio control as an advanced process control solution for continuous twin‐screw wet granulation

Assuring compliance of intermediate and final quality attributes in a continuous pharmaceutical manufacturing campaign is of utmost importance. Application of corrective actions might be required in real‐time. This work exemplifies the steps needed to identify a linear pulse transfer function for the dynamic behavior of the granule liquid‐to‐solid ratio (%w/w) at the end of the granulation unit of a commercial ConsiGma^TM‐25 production line. Near‐infrared spectroscopy was used to monitor the granule composition in‐line. The outcome for both the tracking and regulator problem using either conventional or model predictive control was implemented and evaluated. Dynamic setpoints were correctly followed and an RMSE of 0.25%w/w with respect to the setpoint was obtained when inducing artificial disturbances. Important practical challenges were also tackled. Examples are fouling, computational limitations, and the limited flexibility of the automation software. Applying the proposed advanced process control solution offers an answer to upstream material flow rate deviations. © 2018 American Institute of Chemical Engineers AIChE J, 64: 2500–2514, 2018     

Metal complexation properties of freshwater dissolved organic matter are explained by its aromaticity and by anthropogenic ligands

Dissolved organic matter (DOM) in surface waters affects the fate and environmental effects of trace metals. We measured variability in the Cd, Cu, Ni, and Zn affinity of 23 DOM samples isolated by reverse osmosis from freshwaters in natural, agricultural, and urban areas. Affinities at uniform pH and ionic composition were assayed at low, environmentally relevant free Cd, Cu, Ni, and Zn activities. The C-normalized metal binding of DOM varied 4-fold (Cu) or about 10-fold (Cd, Ni, Zn) among samples. The dissolved organic carbon concentration ranged only 9-fold in the waters, illustrating that DOM quality is an equally important parameter for metal complexation as DOM quantity. The UV-absorbance of DOM explained metal affinity only for waters receiving few urban inputs, indicating that in those waters, aromatic humic substances are the dominant metal chelators. Larger metal affinities were found for DOM from waters with urban inputs. Aminopolycarboxylate ligands (mainly EDTA) were detected at concentrations up to 0.14 μM and partly explained the larger metal affinity. Nickel concentrations in these surface waters are strongly related to EDTA concentrations (R2=0.96) and this is underpinned by speciation calculations. It is concluded that metal complexation in waters with anthropogenic discharges is larger than that estimated with models that only take into account binding on humic substances.     

The copper-mobilizing-potential of dissolved organic matter in soils varies 10-fold depending on soil incubation and extraction procedures

Copper is mobilized in soil by dissolved organic matter (DOM) but the role of DOM quality in this process is unclear. A one-step resin-exchange method was developed to measure the Cu-Mobilizing-Potential (CuMP) of DOM at pCu 11.3 and pH 7.0, representing background values. The CuMP of DOM was measured in soil solutions of 13 uncontaminated soils with different DOM extraction methods. The CuMP, expressed per unit dissolved organic carbon (DOC), varied 10-fold and followed the order water extracts > 0.01 M CaCl2 extracts > pore water. Soil solutions, obtained from soils that were stored air-dry for a long time or were subjected to drying-wetting cycles, had elevated DOC concentration, but the DOM had a low CuMP. Prolonged soil incubations decreased the DOC concentration and increased the CuMP, suggesting that most of the initially elevated DOM is less humified and has lower Cu affinity than DOM remaining after incubation. A significant positive correlation between the specific UV-absorption of DOM (indicating aromaticity) and CuMP was found for all DOM samples (R(2) = 0.58). It is concluded that the DOC concentration in soil is an insufficient predictor for the Cu mobilization and that DOM samples isolated from air-dried soils are distinct from those of soils kept moist.     

Furan formation in starch-based model systems containing carbohydrates in combination with proteins,ascorbic acid and lipids

Formation of the “possibly carcinogenic” furan during thermal treatment of a starch-based model food system containing selected sugars alone and in the presence of proteins, ascorbic acid and lipids, respectively, was investigated. The results showed that in starch gels containing various sugars significantly more furan was formed at pH 6 than at pH 4. Moreover, addition of whey proteins enhanced the generation of furan considerably at both pH values tested. In acidic conditions, no significant difference was observed between the amounts of furan found in a starch–carbohydrate–ascorbic acid model system and those formed in a starch-based samples containing only ascorbic acid. Addition of fresh lipids did not affect furan formation. However, when oxidised soybean oil was applied, the generated amounts of furan were higher than expected from the sum of furan found in the separate starch–carbohydrate and starch–lipid samples. Interestingly, the most efficient carbohydrate in furan generation, among the sugars tested, at pH 6, was lactose, especially when heated in the presence of proteins. This is the first report on the generation of furan from lactose.     

Stability of acrylamide in model systems and its reactivity with selected nucleophiles

Since the discovery of relatively high amounts of the carcinogenic acrylamide in heat-processed food products, many studies have been devoted to the formation of acrylamide. However, as acrylamide is an α,β-unsaturated amide, subsequent reactions can provoke the desired removal of this compound. Therefore, the stability of acrylamide and its reactivity with various food-relevant nucleophiles were studied.The results showed that acrylamide was quite stable in aqueous solutions, but much less in dry reaction conditions. Buffer type and pH had a significant influence on the decrease of free acrylamide. The presence of amino acids with a nucleophilic side chain considerably decreased the free acrylamide, due to Michael-type addition reactions. The highest reactivity was noted for cysteine, leading to the formation of the mono-addition product cysteine-S-β-propionamide, as well as to the double addition product. Other nucleophiles, such as lysine, arginine, serine and ascorbic acid, were less reactive, but yielded comparable condensation products.     

Fate and effect of zinc from tire debris in soil

Tire debris contains significant quantities of zinc (Zn), and there is concern about the diffuse Zn contamination of soils from tire wear. An experiment was set up to quantify the fate and effect of Zn from tire debris in soil. Two different soils were mixed with the <100-microm fraction of car and truck tire debris (25 g kg(-1) soil) or zinc sulfate (ZnSO4) as a reference. Soils were transferred to soil columns with free drainage and placed outdoors for 11 months. Leachates of the tire debris amended soils did not contain significantly (P>0.05) more Zn than control soils except for a 3-fold increase in one soil amended with cartire debris. The increase in Zn leaching due to tire debris was only 3% of the corresponding increase in the ZnSO4 treatment at the same total Zn in soil. Tire debris application increased the soil nitrification potential, whereas ZnSO4 application, at corresponding or smaller total Zn concentration, decreased nitrification potential. An increase in soil pH was observed in all soils treated with tire debris and explains the increased nitrification potential. About 10-40% of the Zn from tire debris was isotopically exchangeable in soil sampled after 1 year weathering. It is concluded that a significant fraction of Zn is released from the rubber matrix within 1 year, but the parallel increase in soil pH limits the mobilization of Zn in soil.     

Zinc toxicity to nitrification in soil and soilless culture can be predicted with the same biotic ligand model

The inhibitory effect of Zn on the nitrification process in ZnCl2 spiked soils (12 soils, pH range 4.8-7.5) was compared to toxic effects of Zn on the nitrification by Nitrosospira sp. in soilless solutions with varying pH (pH 6-8) and ionic composition. The nitrification was reduced by 20% at Zn solution concentrations (EC20) ranging between 7 and 1200 microM Zn in the soil pore water and between 5 and 150 microM Zn in the soilless solutions. Protective effects of H+, Ca2+, and Mg2+ against Zn2+ toxicity were observed in both systems. Zinc speciation was determined, and 60-90% of the Zn in the soils and 35-80% of the Zn in the soilless solutions was present as Zn2+. A biotic ligand model and a Freundlich-type model, incorporating the competition of Zn2+ ions with H+, Ca2+, and Mg2+ for binding on the biotic ligands, were used to model the results. The Zn2+ activities resulting in 20% reduction of the nitrification were well predicted using the same parameters for both (soil and soilless) systems, indicating that microorganisms in soil are exposed to zinc through the free zinc ion in soil pore water.