Optimization of Sesame Oil Extraction by Screw-Pressing at Low Temperature

Box-Behnken designs were used to optimize a process for sesame oil extraction by screw-pressing at low temperature (50 °C). Experimental designs included seed moisture content (SMC), pressing speed (PS), and restriction die (RD) as the main processing parameters. Extractions at pilot plant scale showed a peak in oil recovery (OR, 71.1 ± 2.80%) at 12.3% SMC, 4 mm RD, and 20 rpm PS. Theoretical models were scanned against experimental data in order to scale up the proposed oil extraction process to industrial scale. A fitted model for OR showed a maximum predicted value similar to the highest experimental value (74.4 ± 1.23%) under the following conditions: 8.03% SMC, 10 mm RD, and 20 rpm PS. Chemical quality parameters of oils obtained at both pilot and industrial scales were in the ranges stated in Codex (FAO/WHO) standards for non-refined sesame oil.     

A novel method to monitoring changes in cognitive load in video‐based learning

One of the golden rules in instructional design methods is to optimize the use of working memory capacity and avoid cognitive overload. The study of cognitive load has historically relied on one's introspection. However, it is difficult to capture changes in cognitive load levels during learning sensitively. This paper suggests an approach to investigating dynamic changes in cognitive load by using a pupillometry. With the method, this study explores the effects of learners' prior knowledge and task complexity on cognitive load. An experiment was conducted on two groups of students (N = 19) with distinct levels of prior knowledge. In the experimental session, participants watched a video lecture on a mathematics proposition, while being eye‐tracked. The lecture consists of sections, which can be either a high task complexity or a low task complexity based on elements they have. Pupil dilations acquired in each section were used to explore the time course of cognitive load. To formulate cognitive load patterns, a time‐series clustering was used. The research conducted a chi‐square analysis to test differences in cognitive load patterns by prior knowledge and task complexity. Results show that pupil dilation patterns can be applied to monitor changes in cognitive load during learning.     

Admissibility and stabilization of singular continuous 2D systems described by Roesser model

Multidimensional Systems and Signal Processing - The paper considers first, the admissibility conditions for continuous 2D systems represented by Roesser model by dealing with non-strict LMIs....     

Confirmation of fenthion metabolites in oranges by IT-MS and QqTOF-MS

Identification of degradation products of the organophophorous pesticide fenthion formed in two orange varieties, Valencia Navel and Navel Late, under field conditions has been assessed using liquid chromatography quadrupole time-of-flight mass spectrometry and ion trap mass spectrometry. The structural elucidation of the metabolites was accomplished by the accurate mass measurements provided by the quadrupole time-of-flight mass spectrometer in MS and MS/MS modes. This instrument achieved elemental composition diagnosis for the precursor and product ions with absolute mass error of <5 ppm, which unambiguously establishes the identity of the metabolites even at low concentration. The presence of these compounds was also confirmed by electrospray ionization-ion trap mass spectrometry, performing successive fragmentation steps (MS(n)). Once identified, each molecule was confirmed by comparison with its analytical standard, also used to explore the quantitative capabilities of both mass analyzers. The extraction method was evaluated because it predetermines the metabolites that can be found (e.g., according to their polarity). Recoveries ranged from 70% for fenoxon sulfoxide (the most polar) to 101% for fenthion (the most apolar), which also indicates the method's facility to extract other more polar metabolites if present. Satisfactory linear range (r > 0.99) of more than 2 orders of magnitude was obtained with both analyzers for standards prepared in methanol and in untreated orange extracts. However, the matrix-matched standards showed suppression of the mass signal due to the matrix effect, especially for fenoxon sulfoxide and sulfone. The limits of quantification ranged from 0.005 to 0.015 mg/kg. The QqTOF-MS provided better quantification limits for fenthion and its sulfoxide and sulfone than the IT-MS. The resulting fenthion degration curves in oranges indicated that it was mainly degraded by sunlight photolysis to its sulfoxide and sulfone. However, hydrolysis was also observed by the appearance of fenoxon, fenoxon sulfoxide, and fenoxon sulfone, but always in low concentrations, which can be related to the rain events.     

Analysis of adhesive interface in root canals irradiated by Er,Cr:YSGG laser after luting a fiber post

This study evaluated the effect of Er,Cr:YSGG laser on the root canal dentin after luting a fiber post. Twenty‐four bovine teeth roots were prepared using NiTi instruments and filled with Sealer 26 and gutta‐percha. Post spaces were prepared and roots were distributed according to dentin treatment (n = 8): 2.5%NaOCl (group control), Er,Cr:YSGG laser (1.5 W, 20 Hz, 20 s) (group test 1) or 2.5%NaOCl + Er,Cr:YSGG laser (group test 2). Fiber posts were luted using adhesive cement (Rely X U200, 3M) and roots were prepared to confocal laser scanning microscopy (CLSM) and scanning electron microscope (SEM). The morphology of interface, thickness of cement, and the gaps and tags were analyzed. Non‐parametrical data for thickness of cement were submitted to Friedman and Kruskall–Wallis tests (α = 0.05) and parametrical data for gaps to ANOVA (α = 0.05). CLSM of the cement thickness and gaps revealed no significant difference in surface treatment (NaOCl, Er,Cr:YSGG laser and NaOCl + Er,Cr:YSGG laser) (p > .05) and canal thirds (cervical, middle, and apical) (p > 0.05). SEM showed tags and a residual layer of cement adhered to dentin, mainly in laser‐irradiated specimens. The pretreatment of root canal with Er,Cr:YSGG laser previously to luting the fiber post with a self‐adhesive cement did not influence the cement thickness and gaps but affected the dentin interaction.     

Lipid Metabolism in Rats is Modified by Nitric Oxide Availability Through a Ca<Superscript>++</Superscript>-Dependent Mechanism

We studied lipid metabolism and the antioxidant defense system in plasma and liver of rats fed diets supplemented with l ^ω-nitro-l-arginine methyl ester (l-NAME), isosorbide dinitrate (DIS), l-arginine (Arg), or the associations of these drugs. Liver hydroperoxide and thiobarbituric-acid-reactive substance (TBARS) levels were decreased by Arg and increased by l-NAME or DIS treatments. Oxidized glutathione and conjugated dienes were increased by DIS. Nitrate + nitrite levels and serum calcium ([Ca⁺⁺]) were incremented by Arg or DIS and reduced by l-NAME. Superoxide dismutase and catalase activities decreased under Arg treatment, while l-NAME or DIS caused stimulation. Liver high-density lipoprotein (HDL) cholesterol was increased by DIS or NAME (alone or associated with Arg). Free fatty acids and neutral and polar lipids were increased by Arg, l-NAME, and DIS. However, predominating phospholipid synthesis increased the neutral/polar ratio. Decreased levels of nitric oxide (NO) (low [Ca⁺⁺]) was directly associated with increased fatty acid synthetase, decreased phospholipase A₂, carnitine-palmitoyl transferase, and fatty acid desaturase activities. Raised NO (high [Ca⁺⁺]) inversely correlated with increased phospholipase-A₂ and acyl-coenzyme A (CoA) synthetase and decreased fatty acid synthetase and β-oxidation rate. Arg or DIS produced changes that were partially reverted by association with l-NAME. Based on these observations, prolonged therapeutical approaches using drugs that modify NO availability should be carefully considered. Julio Nella author in memoriam.     

Biodegradation of sulfamethazine by Trametes versicolor: Removal from sewage sludge and identification of intermediate products by UPLC-QqTOF-MS

Degradation of the sulfonamide sulfamethazine (SMZ) by the white-rot fungus Trametes versicolor was assessed. Elimination was achieved to nearly undetectable levels after 20 h in liquid medium when SMZ was added at 9 mg L^− 1. Experiments with purified laccase and laccase-mediators resulted in almost complete removal. On the other hand, inhibition of SMZ degradation was observed when piperonilbutoxide, a cytochrome P450-inhibitor, was added to the fungal cultures. UPLC-QqTOF-MS analysis allowed the identification and confirmation of 4 different SMZ degradation intermediates produced by fungal cultures or purified laccase: desulfo-SMZ, N⁴-formyl-SMZ, N⁴-hydroxy-SMZ and desamino-SMZ; nonetheless SMZ mineralization was not demonstrated with the isotopically labeled sulfamethazine-phenyl-¹³C₆ after 7 days. Inoculation of T. versicolor to sterilized sewage sludge in solid-phase systems showed complete elimination of SMZ and also of other sulfonamides (sulfapyridine, sulfathiazole) at real environmental concentrations, making this fungus an interesting candidate for further remediation research.     

Fully automated determination in the low nanogram per liter level of different classes of drugs of abuse in sewage water by on-line solid-phase extraction-liquid chromatography-electrospray-tandem mass spectrometry

The present work describes the first fully automated method, based on on-line solid-phase extraction (SPE)-liquid chromatography-electrospray-tandem mass spectrometry, developed for the determination of drugs of abuse (17 compounds and metabolites belonging to the classes of amphetaminics, cannabinoids, cocainics, opiates, and lysergics) in sewage waters. On-line SPE is performed by passing 5 mL of the water sample through a PLRP-s cartridge for analytes measured in positive ionization mode (all but cannabinoids) and through an Oasis HLB cartridge for analytes measured in negative ionization mode (cannabinoids). For unequivocal identification and confirmation two selected reaction monitoring transitions are registered per compound, thus achieving the four identification points requested by the European Union for banned substances. Quantitation is performed by the internal standard method, indispensable to correct for matrix effects. The main advantages of the method developed are high sensitivity (limits of determination between 0.69 and 5.97 ng/L), selectivity and reliability of results, minimum sample manipulation, full automation, and fairly high throughput (analysis time per sample is 2 x 35 min). As a part of the validation procedure, the method developed has been applied to the analysis of various influent and effluent samples from four Spanish sewage treatment plants.     

Population Growth Rate Responses of Ceriodaphnia dubia to Ternary Mixtures of Specific Acting Chemicals: Pharmacological versus Ecotoxicological Modes of Action

When considering joint toxic apical effects at higher levels of biological organization, such as the growth of populations, the so-called pharmacological mode of action that relies on toxicological mechanistic effects on molecular target sites may not be relevant. Such effects on population growth rate will depend on the extent to which juvenile and adult survival rates and production rates (juvenile developmental rates and reproduction) are affected by toxic exposure and also by the sensitivity of population growth rates to life-history changes. In such cases, the ecotoxicological mode of action, defined as the crucial life-history trait processes and/or xenobiotic-life-history trait interactions underlying a toxicological effect on population growth rate, should be considered. Life-table response experiments with the crustacean Ceriodaphnia dubia exposed to single and ternary mixtures of nine compounds were conducted to test the hypothesis that joint effects on population growth rates could be predicted from the mixture constituent ecotoxicological mode of action. Joint effects of mixtures containing pharmacologically dissimilar compounds (cadmium, λ-cyhalothrin, and chlorpyrifos) that differentially affected life-history traits contributing to population growth rates were accurately predicted by the independent-action concept. Conversely, the concentration-addition concept accurately predicted joint effects of two different mixtures: one containing pharmacologically similar acting pyrethroids that also affected similarly life-history traits, the other one that included pharmacologically dissimilar compounds (3,4-dichloroaniline, sodium bromide, and fenoxycarb) acting mainly on reproduction rates. These results indicate that when assessing combined effects on population growth rate responses, selection of mixture toxicity conceptual models based on the ecotoxicological mode of action of mixture constituents provided more accurate predictions than those based on the pharmacological mode of action.