Radical-scavenging activity of extracts from Cordia verbenacea DC obtained by different methods

The possibility of using the leaves of Cordia verbenacea as a new source of natural antioxidant compounds was investigated. In the present work, extracts from C. verbenacea were obtained using different extraction methods: supercritical fluid extraction (SFE), Soxhlet (SE), hydrodistillation and maceration, with the objective to evaluate the methods in terms of yield and antioxidant potential. The high-pressure technique was applied using pure CO₂ and CO₂ with co-solvent at different temperatures and pressures (30, 40 and 50 °C and 100, 200, and 300 bar). Organic solvents with different polarities were used to obtain extracts by low-pressure extraction processes. The extracts were evaluated according to their antioxidant activity using total phenolic content, scavenging abilities on DPPH radical, total antioxidant activities (ABTS^•+), superoxide anion radical-scavenging (O₂^•) and protection against lipid peroxidation in vitro (LPO). Ethyl acetate fraction obtained by maceration and extract isolated by SE using 25% aqueous mixture of ethanol possessed the highest scavenger activity against DPPH radical (IC₅₀ = 9.2 ± 0.4 μg/ml, IC₅₀ = 27.4 ± 0.1 μg/ml, respectively). The SFE with 8% ethanol as a co-solvent produced extracts with distinguished increase in the antioxidant activity. The Soxhlet extract with ethyl acetate exhibited a strong reduction of lipid peroxidation (IC₅₀ = 209 ± 3 μg/ml) value comparable to the standard rutin (IC₅₀ = 203 ± 2 μg/ml). The results indicate that extracts of C. verbenacea have important potential as a source of bioactive compounds with antioxidant activity.     

Customer Integration during Innovation Development: An Exploratory Study in the Logistics Service Industry

Previous research has shown that though customer integration during innovation development can enhance companies' innovation performance, it can also harm innovativeness. A possible reason for these contradicting findings is that innovation development is a dynamic process that requires different tasks. Thus, a more fine‐grained picture of how customer‐oriented companies engage in customer integration throughout the entire innovation development process is necessary. This article contributes to the innovation and marketing literature by providing insights into how companies co‐create knowledge about customer needs relevant for innovation development. Using a multiple case study design, this study examines four substantive cases that illustrate the activities logistics service providers undertake to integrate customers during the process of idea generation, development and implementation. The results show that companies focus on both proactive and reactive customer integration during idea generation and implementation but refrain from reactive customer integration during development.     

Effects of enzymatic hydrolysis on lentil allergenicity

Enzymatic hydrolysis and further processing are commonly used to produce hypoallergenic dietary products derived from different protein sources, such as cow's milk. Lentils and chickpeas seem to be an important cause of IgE‐mediated hypersensitivity in the Mediterranean area and India. Some studies have investigated the effects of enzymatic treatments on the in vitro immunological reactivity of members of the Leguminosae family, such as soybean, chickpea, lentil, and lupine. Nevertheless, there are only a few studies carried out to evaluate the effect on IgE reactivity of these food‐hydrolysis products with sera from patients with well‐documented allergy to these foods. In this study, lentil protein extract was hydrolyzed by sequential action of an endoprotease (Alcalase) and an exoprotease (Flavourzyme). Immunoreactivity to raw and hydrolyzed lentil extract was evaluated by means of IgE immunoblotting and ELISA using sera from five patients with clinical allergy to lentil. The results indicated that sequential hydrolysis of lentil results in an important proteolytic destruction of IgE‐binding epitopes shown by in vitro experiments. However, some allergenic proteins were still detected by sera from four out of five patients in the last step of sequential hydrolyzation.     

Determination of Total Nitrosamines in Vegetables Cultivated Organic and Conventional Using Diamond Electrode

Vegetables were analyzed for total N-nitrosamines (NAs) and the influence of disinfection processes was assessed. Differences in NAs found in cabbage, spinach, and broccoli were determined by square wave voltammetry using a boron-doped diamond electrode. Analysis of samples showed that all samples contained detectable levels of NAs but the results indicated that organic contained less than conventionally grown products. The sum of the total NAs was higher in the cabbage samples, ranging between 2.8–3.1 ppb and lower in broccoli samples at 0.2–1.1 ppb. The method described is simple, rapid, selective, and sensitive. The results suggested that the disinfection process affects the level of NAs, in this manner affecting the level of human exposure to NAs.     

On the quantization of the electromagnetic field in conducting media

In this work we investigate the quantization of electromagnetic waves propagating through homogeneous conducting linear media with no charge density. We use Coulomb's gauge to reduce the problem to that of a time-dependent harmonic oscillator, which is described by the Caldirola–Kanai Hamiltonian. Furthermore, we obtain the corresponding exact wave functions with the help of quadratic invariants and of the dynamic invariant method. These wave functions are written in terms of a particular solution of the Milne–Pinney equation. We also construct coherent and squeezed states for the quantized electromagnetic waves and evaluate the quantum fluctuations in coordinates and momentum as well as the uncertainty product for each mode of the electromagnetic field.     

Development of an Analytical Method Based in the Slurry Sampling for Iron Determination in Fortified Milk Powder by HR-CS FAAS

The use of slurry sampling as the procedure for sample preparation provides simplicity, speed, and low consumption of reagents in analytical methods. In this paper, a method based on slurry sampling for the determination of iron in samples of fortified milk powder by high-resolution continuum source flame atomic absorption spectrometry was developed. Multivariate design techniques were applied for the optimization of experimental conditions of the method for a sample mass of 100 mg, final volume of slurry of 10 mL, and using the absorbance signal as response. Initially, a two-level full factorial design was used for the preliminary evaluation of the variables involved in slurry preparation: concentration hydrochloric acid, Triton X-100 concentration, and sonication time. Then, the Doehlert matrix was applied for the determination of the critical conditions: 2.5 mol L⁻¹ hydrochloric acid and sonication time of 20 min. External calibration technique with aqueous standard was used for the quantification of iron. This way, the method allowed iron determination with limits of detection and quantification of 0.9 and 3.0 μg g⁻¹, respectively. The precision expressed as the relative standard deviation was evaluated under repeatability and reproducibility conditions, being 3.2% and 4.0%, respectively. Addition/recovery test was used for assessing the accuracy of the method, and the recovery values achieved were in the range of 90–110%. The method was applied for iron determination in eight samples of fortified milk powder, and the obtained concentrations varied from 95.4 to 295.6 μg g⁻¹. The results were compared with those obtained after acid digestion, and no significant difference was observed applying t test at the 95% confidence level.     

Stereocontrolled Construction of Quaternary Stereocenters by Inter‐ and Intramolecular Nitro‐Michael Additions Catalyzed by Bifunctional Thioureas

A highly diastereo‐ and enantioselective conjugate addition of β‐keto esters to nitroolefins, catalyzed by a chiral thiourea prepared from L ‐valine is described. The formation of two contiguous tertiary and quaternary stereocenters occurs in high yield and excellent diastereo‐ and enantioselection with only 2 mol% of catalyst loading. The reaction is general and different β‐keto esters and aryl‐ and alkylnitroolefins have been tested. The same catalyst has been used to promote the first intramolecular conjugate addition leading to the cyclic adduct in moderate diastereoselectivity and good enantioselectivity.