Fractionation and Bioaccessibility of Manganese,Copper, Zinc,Cadmium, and Lead in Commercial Vegetable and Rice Baby Foods Using Inductively Coupled Plasma - Mass Spectrometry (ICP-MS) with Central Composite Design (CCD)

Abstract

Herein the bioaccessibility of Mn, Cu, Zn, Cd, and Pb, selected from essential and toxic elements, was determined in commercially sold vegetable purees intended for infant and toddler consumption. Chemical fractionation studies using water, acetone, diethyl ether, chloroform:methanol, and n-hexane were employed to predict the importance of the protein and lipid parts of a matrix to assess the bioaccessibility data. In addition, in-vitro gastrointestinal digestion was performed to determine the bioaccessibility of the elements using a five level, three factor central composite design (CCD) to maximize the elemental solubility. The total elemental concentrations in all of the fractions were determined by inductively coupled plasma – mass spectrometry (ICP-MS). Based on the consumption of one jar of vegetable/rice-based baby food, Zn was 1.3% of the recommended dietary allowance and Mn was 4.2% of the adequate intake level, while Cu was almost 100% of the adequate intake level. Additionally, Pb was always below the detection limit and Cd was sometimes under the detection limit for the percent bioaccessibility. However, in some samples, Cd was as high as 80% of the tolerable weekly intake level depending on the body weight.     

Synthesis of some 6,8‐diarylimidazo[1,2‐a]pyrazine derivatives by using either reflux or microwave irradiation method and investigation of their anticancer activities

In order to obtain some 6,8‐diarylimidazo[1,2‐a]pyrazines, 1‐(2‐aryl‐2‐oxoethyl)‐2‐aryloylimidazole derivatives were reacted with ammonium acetate in acetic acid by using a new method different from that found in the literature. Anticancer activities of the compounds obtained were evaluated and the noticeable activity values were reported.     

Near-IR photoluminescence from Si/Ge nanowire-grown silicon wafers: effect of HF treatment

We present the room-temperature near-infrared (NIR) photoluminescence (PL) properties of Si/Ge nanowire (NW)-grown silicon wafers which were treated by vapor of HF:HNO₃ chemical mixture. This treatment activates or enhances the PL intensity in the NIR region ranging from 1000 nm to 1800 nm. The PL consists of a silicon band-edge emission and a broad composite band which is centered at around 1400–1600 nm. The treatment modifies the wafer surface particularly at defect sites especially pits around NWs and NW surfaces by etching and oxidation of Si and Ge. This process can induce spatial confinement of carriers where band-to-band (BB) emission is the dominant property in Si-capped strained Si/Ge NW-grown wafers. Strong signals were observed at sub-band-gap energies in Ge-capped Si/Ge NW-grown wafers. It was found that NIR PL is a competitive property between the Si BB transition and deep-level emission, which is mainly attributable to Si-related defects, Ge dots and strained Ge layers. The enhancement in BB and deep-level PL is discussed in terms of strain, oxygen-related defects, dot formation and carrier-confinement effects. The results demonstrate the effectiveness of this method in enhancing and tuning NIR PL properties for possible applications.     

Determination of some phthalate acid esters in artificial saliva by gas chromatography-mass spectrometry after activated carbon enrichment

The determination of six phthalate acid esters was achieved in artificial saliva using gas chromatography-mass spectrometry following activated carbon enrichment of samples. Central composite experimental design was applied to optimize method parameters, such as pH, adsorption time and amount of activated carbon. The best compromise of analytical conditions for the simultaneous determination of analytes from spiked artificial saliva were found to be: pH (3), adsorption time (30 min), activated carbon amount (1.8 g L⁻¹) and elution solvent (chloroform). These conditions were applied to study the migration of phthalate acid esters from different children's toys into saliva. A horizontal agitation method was applied to extract the analytes from plastic toys into saliva for 2 h at 37 °C. The detection limits of the method were in the range of 1.3-5.1 μg L⁻¹, while the relative standard deviation (%) values for the analysis of 100 μg L⁻¹ of the analytes were below 3.0% (n = 5). Di-2-ethylhexyl phthalate was the main analyte found in these samples.     

Synthesis of two new p-tert-butylcalix[4]arene β-ketoimin derivatives for extraction of dichromate anion

In this study the selective derivatization of p-tert-butylcalix[4]arene was carried out and two new p-tert-butylcalix[4]arene β-ketoimin, 5,11,17,23-tetra-tert-butyl-25,27-bis-3-methyl-[(β-ketoimine)-ethoxy]-26,28-dihydroxycalix[4]arene (4), and 5,11,17,23-tetra-tert-butyl-25,27-bis-3-chloro-[(β-ketoimine)-ethoxy]-26,28-dihydroxycalix[4]arene (5) have been synthesized. In the synthesis, the lower rim of p-tert-butylcalix[4]arene was modified in order to acquire binding site for the recognition of dichromate anion. It was observed that these ionophores 4 and 5 showed high affinity towards dichromate anion. The protonated Schiff-base forms of the receptors were effective for transferring the HCr₂O₇ ^? anion from aqueous phase to a dichloromethane phase.     

A facile synthesis of some thieno/furo‐[2,3‐d]pyrimidine‐2‐yl‐thioacetic acid derivatives

The reaction of 2‐(α‐chloroacetamido)‐3‐cyano‐4,5‐disubstituted thiophenes/furanes with ammonium thiocyanate in methanol or ethanol afforded methyl or ethyl (4‐amino‐5,6‐disubstituted thieno/furo[2,3‐d]‐pyrimidine‐2‐yl)thioacetates in good yields.     

A novel method to obtain a real-time control force strategy using genetic algorithms for dynamic systems subjected to external arbitrary excitations

The paper deals with a discrete differential dynamic programming type of problem. It is an optimal control problem where an external disturbance is controlled over the time horizon by a control force constituted with the well-known convolution approach. The paper presents a simple and novel idea to achieve an optimally controlled response when a linear system is subjected to an arbitrary external disturbance. The proposed approach uses the convolution concept and states that if a control method can be established to restore a unit external disturbance, then the convolution integral can be applied to generate an overall control strategy to control the system when it is subjected to an arbitrary external disturbance. In spite of its simplicity, such a strategy has not been encountered in the literature. The only requirement for this method to be useful is to obtain an optimal control strategy to suppress the vibration of the system when it is subjected to unit response disturbance. To accomplish this, a method from classical optimal control theory such as linear quadratic regulator (LQR) that involves solving the Riccati equation of the associated system can be used. However, genetic algorithm (GA) can be adopted as an alternative way to obtain an optimal control strategy against impulse input. As any arbitrary excitation can be divided into impulses, the convolution concept will constitute the overall optimal control strategy for any arbitrary excitation with simply shifting, scaling and summation (or integration) of the GA-optimized control strategy for each impulse of the arbitrary excitation. The proposed method can be used for real time control applications. Once the control strategy for the impulse disturbance is established, the results can then be used at each time step when online control is performed. Computer simulations were carried out to control the response of a quarter-vehicle active suspension system using the proposed method. The obtained results were compared to those of linear quadratic regulator (LQR) and passive suspension applications. The overall results demonstrated the effectiveness of the proposed method for active suspension systems, especially in suppressing the vehicle body displacement when compared to both the LQR based and passive systems. Furthermore, such a control system proves to be simpler requiring less information to process, which is crucial for real-time applications.     

Platinum(II)-thiosemicarbazone drugs override the cell resistance due to glutathione; assessment of their activity against human adenocarcinoma cells

New platinum(II) compounds of the thiosemicarbazone 1-(1H-Benzimidazol-2-yl)ethan-1-one thiosemicarbazone (BzimetTSCH), [Pt(BzimetTSCH)Cl]·2H₂O (1) and [Pt(BzimetTSCH)(tpp)]Cl·H₂O·MeCN (2) were synthesized. The complexes were characterized by FT-IR spectroscopy and ¹H NMR spectroscopy. The crystal structures of 1 and 2 were determined with single-crystal X-ray diffraction analysis. The coordination around platinum is square planar in both complexes. Compounds 1 and 2 were evaluated for their in vitro cytotoxic activity against human adenocarcinoma breast (MCF-7) and cervix (HeLa) cells. The apoptotic pathway of cell death was confirmed by cell cycle arrest test. Since deactivation of cisplatin caused by glutathione (GSH) seems to be an important determinant of its cytotoxic effects, the reactions of 1 and 2 with GSH were investigated by UV-absorption spectroscopy. The genotoxicities on normal human fetal lung fibroblast cells (MRC-5) caused by 1 and 2 were evaluated by fluorescence microscopy. The absence of micronucleus in MRC-5 cells confirms the in vitro non toxic behavior of the compounds. Moreover, the in vivo genotoxicities of 1 and 2 were evaluated by the Allium cepa test. Due to negligible genototoxic effect and high antitumor activity which is similar to that of cisplatin, 2 could be a candidate for further study as potential drug since the mitotic index is unchanged.     

Effects of process parameters on supercritical CO2 extraction of total phenols from strawberry (Arbutus unedo L.) fruits: An optimization study

The aim of this work was to optimize total phenolic yield of Arbutus unedo fruits using supercritical fluid extraction. A Box–Behnken statistical design was used to evaluate the effect of various values of pressure (50–300 bar), temperature (30–80°C) and concentration of ethanol as co‐solvent (0–20%) by CO₂ flow rate of 15 g/min for 60 min. The most effective variable was co‐solvent ratio (p<0.005). Evaluative criteria for both dependent variables (total phenols and radical scavenging activity) in the model were assigned maximum. Optimum extraction conditions were elicited as 60 bar, 48°C and 19.7% yielding 25.72 mg gallic acid equivalent (GAE) total phenols/g extract and 99.9% radical scavenging capacity, which were higher than the values obtained by conventional water (24.89 mg/g; 83.8%) and ethanol (15.12 mg/g; 95.8%) extractions demonstrating challenges as a green separation process with improved product properties for industrial applications.     

On sharp asymptotic formulas for the Sturm–Liouville operator with a matrix potential

In this article we obtain the sharp asymptotic formulas for the eigenvalues and eigenfunctions of the non-self-adjoint operators generated by a system of the Sturm–Liouville equations with Dirichlet and Neumann boundary conditions. Using these asymptotic formulas, we find a condition on the potential for which the root functions of these operators form a Riesz basis.