Determination of Metals in Fruits of Cucurbitaceae Species from South Korea,to Characterize Potential Effects on Human Health

Recent research studies have confirmed that the dietary intake of vegetables and fruits has a positive and profound impact on human health, performance, and disease. This research was designed to determine the concentrations of essential trace elements; cobalt (Co), chromium (Cr), copper (Cu), manganese (Mn), selenium (Se), vanadium (V), and zinc (Zn), toxic metals; cadmium (Cd), mercury (Hg), and lead (Pb); and a metalloid; arsenic (As) in fruits of seven species of Cucurbitaceae family including gourd, zucchini, pumpkin, sweet pumpkin, melon, watermelon, and oriental melon commonly consumed in South Korea. The concentrations of As, Cd, Co, Cr, Cu, Pb, Se, and Zn were determined using inductively coupled plasma mass spectrometry, and Hg by a mercury analyzer. To analyze the samples after microwave digestion for the validation of analytical techniques, satisfactory values of all quality parameters of linearity, detection limits, precision, accuracy, and recovery experiments were obtained in all cases. On the whole, all analyzed elements were found in accordance to the published literature around the world and well within the critical recommended standards by CODEX and Ministry of Food and Drug Safety, Korea. The estimated daily intake values, and hazard quotients and indices of the analyzed samples were all below the World Health Organization, Joint Food and Agriculture Organization/World Health Organization Expert Committee on Food Additives, and European Food Safety Authority limits.     

A flow visualization study on self-ignition of high pressure hydrogen gas released into a tube

Hydrogen is known as one of the green energy sources for fuel cells and hydrogen-fueled cars in the next generation. The storage of high-pressure hydrogen gas conditions is preferred to its storage in cryogenic liquid state. However, cases of unidentified self-ignitions were reported, notably when the high-pressure hydrogen gas suddenly leaked out. Only a few of numerical simulations have shown visually the processes of the self-ignition inside a tube. This paper presents a flow visualization study to investigate the self-ignition mechanism in a test tube i.e. how the ignition process is initiated and the flame propagates. In addition to visualization, measurement of a number of pressure and light sensors installed in the tube supported the analysis of the self-ignition and flame propagation. The test result showed that self-ignition takes place at the boundary layer behind the front center of mixing zone at first, and the flame propagates to the front of mixing zone and tail of the mixing zone along the boundary layer. It showed that self-ignition is accompanied with complex mixing induced by shock interaction with the mixing front. It is also suggested that the self-ignition boundary has a certain critical threshold of static pressure at the boundary layer, based on various burst pressures of hydrogen.     

Preparation of ZnO nanorods on cellulose fiber paper and their charge‐generating application for waste paper recycling

Zinc oxide (ZnO) nanorod arrays (NRAs) were well integrated on the cellulose fibers (CFs) of waste paper via a facile hydrothermal method. By mechanically blending the waste paper with de‐ionized water, abundant CFs were obtained and used as a sufficient platform for integrating ZnO NRAs. After coating a thin ZnO seed layer onto the surface of CFs and subsequent thermal treatment, the ZnO NRAs were densely grown, exhibiting high crystallinity and good photoluminescence properties. Their sizes were readily controlled by changing the concentration of the growth solution. To test the feasibility of an energy harvesting application using the prepared samples, the piezoelectric charge generation was explored under an external pushing force for the fabricated devices with polydimethylsiloxane‐shielded ZnO NRAs on CFs for good contact to two electrodes (i.e., gold and indium tin oxide). This nanotechnology of recycling waste paper could be considered as a promising candidate for implementation in cost‐effective and environment‐friendly advanced materials and energy production. (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Di­chloro­bis­(tri­methyl­ene­thio­urea‐κS)antimony(III) chloride

In the title compound, [SbCl₂(C₄H₈N₂S)₂]Cl, the coordination around the Sb atom can be described as distorted pseudo‐octahedral. Both rings of the tri­methyl­ene­thio­urea ligands [alternatively 3,4,5,6‐tetrahydropyrimidine‐2(1H)‐thione] adopt an envel­ope conformation. The mol­ecules are connected into dimers in the ab plane by two intermolecular hydrogen bonds. The dimers are arranged into infinite one‐dimensional chains along the a axis as a result of the Cl^? ions forming intermolecular hydrogen bonds with three NH groups.     

The Kinetics of Analcime Synthesis in Alkaline Solution

In this study glass has been used as a starting material in order to increase the resolution of the experiment and establish the kinetics of analcimes during hydrothermal synthesis. The experimental results show that the crystal growth curves represent two‐stage linear growth. The first stage is marked by rapid crystal growth whilst the second stage indicates much slower growth. The nuclei appear before the crystals start growing. The crystal growth rate is dependent on the experimental conditions. The nucleation rate increases as the glass dissolves and reaches a maximum when the glass is completely dissolved. Thereafter, the concentration decreases with the consumption of nutrients, and both nucleation and crystal growth stops when supersaturation occurs.     

Sensing of picric acid with a glassy carbon electrode modified with CuS nanoparticles deposited on nitrogen-doped reduced graphene oxide

We describe the preparation of a nanohybrid consisting of nitrogen doped reduced graphene oxide and CuS nanoparticles (N-rGO/CuS) by in-situ microwave irradiation at weight ratios of 25/75, 50/50, and 75/25. The resulting nanohybrids were characterized by X-ray diffraction, X-ray photoelectron spectroscopy, FTIR, spectroscopy, scanning electron and transmission electron microscopy, electrochemically by cyclic voltammetry and electrochemical impedance analysis. It is shown that the CuS nanoparticles are evenly decorated onto the N-rGO surface. The nanohybrids was placed on glassy carbon electrode (GCE) where they showed electro-reductive activity towards picric acid, typically at working voltages between ?0.2 and ?0.8 V (vs. SCE). Effects of pH value and scan rate were evaluated, and it is shown that two electrons are involved in electro-reduction. The detection limits of the GCE modified with various N-rGO/CuS hybrids (with 25/75, 50/50, and 75/25 wt%) are 6.2, 3.2, and 0.069 μM respectively. The method demonstrates its applicability in sensing of picric acid with good reproducibility.

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Graphical abstract Nitrogen doped reduced graphene oxide nanohybrids was synthesized for the detection of picric acid. A straightforward and preconcentration free analysis of picric acid was successfully demonstrated at nanomolar levels using the nanohybrids.

     

Targeted exome sequencing resolves allelic and the genetic heterogeneity in the genetic diagnosis of nephronophthisis-related ciliopathy

Nephronophthisis-related ciliopathy (NPHP-RC) is a common genetic cause of end-stage renal failure during childhood and adolescence and exhibits an autosomal recessive pattern of inheritance. Genetic diagnosis is quite limited owing to genetic heterogeneity in NPHP-RC. We designed a novel approach involving the step-wise screening of Sanger sequencing and targeted exome sequencing for the genetic diagnosis of 55 patients with NPHP-RC. First, five NPHP-RC genes were analyzed by Sanger sequencing in phenotypically classified patients. Known pathogenic mutations were identified in 12 patients (21.8%); homozygous deletions of NPHP1 in 4 juvenile nephronophthisis patients, IQCB1/NPHP5 mutations in 3 Senior–Løken syndrome patients, a CEP290/NPHP6 mutation in 1 Joubert syndrome patient, and TMEM67/MKS3 mutations in 4 Joubert syndrome patients with liver involvement. In the remaining undiagnosed patients, we applied targeted exome sequencing of 34 ciliopathy-related genes to detect known pathogenic mutations in 7 (16.3%) of 43 patients. Another 18 likely damaging heterozygous variants were identified in 13 NPHP-RC genes in 18 patients. In this study, we report a variety of pathogenic and candidate mutations identified in 55 patients with NPHP-RC in Korea using a step-wise application of two genetic tests. These results support the clinical utility of targeted exome sequencing to resolve the issue of allelic and genetic heterogeneity in NPHP-RC.     

Selective Desorption of Intercalated Bovine Serum Albumin and Lysozyme by Organically Modified Montmorillonite

The organically modified montmorillonite (M‐Mt) was applied as an adsorbent for the purification of bovine serum albumin (BSA). In order to differentiate the selectivity and perform the purification of BSA, two kinds of proteins, BSA and lysozyme (LYZ) were mixed together and prepared at different pH, which could change the electrical charges on the surfaces of the proteins. BSA and LYZ can be adsorbed at the lower pH into the organically modified montmorillonite, which could be confirmed by powder X‐ray diffraction (XRD) in the d‐value increased after the adsorption of proteins. However, there is only BSA desorption was observed, approved by the method of Sodium dodecyl sulfate (SDS)‐polyacrylamide gel electrophoresis (PAGE), from this adsorbed protein mixture when the pH of the solution was adjusted and optimized. These results indicate that there is electrostatic interaction between a suitably modified montmorillonite and proteins BSA and LYZ to perform the selective desorption from BSA in the mixture of these proteins.     

Synthetic preparations,thermal properties and crystallization characterization of PLLA‐PPG block copolymers/clay nanocomposites

In this study, intercalation of the polymer or pre‐polymer from solution was used to blend different proportions of polylactic acid‐propylene glycol (LPG) copolymers (polypropylene glycols (PPG) of : 700, 1000, 2000) and lipophilic montmorillonite (clay) in order to investigate the melting and the crystalline nature of LPG copolymers/clay nanocomposites via a differential scanning calorimeter (DSC). In addition, changes in the intermolecular force and crystal morphology of the nanocomposites under different crystallization conditions were also studied. For the results, it was observed from a thermogravimetric analyzer that increasing the clay content elevated the weight loss temperature. In non‐isothermal experiments using a DSC, it was discovered that the melting temperature and crystallization temperature of the LPG copolymers also increased with increasing amounts of added clay. The crystallinity of LPG2000 + 1.5 wt% clay was enhanced by 17.00%; in addition, it was found in the crystallinity study that adding clay slowed down the crystallization rate of the LPG copolymers. Moreover, it was found via X‐ray diffractometer (XRD) that the intensity of the diffraction peaks of the 1.5 wt% specimen was stronger than that of the 0.5 wt% specimens. The results imply that copolymers with a longer chain length provide greater space for the crystals to grow, thus making it easier for larger crystals to grow. Conversely, the added clay generates an inhibitory effect in copolymers, reducing the d‐spacing (d) in the XRD. Therefore, adding clay would change the crystallization behavior and the morphology of the LPG copolymers. Copyright © 2015 John Wiley & Sons, Ltd.     

Synthesis of Diverse N‐Substituted Muramyl Dipeptide Derivatives and Their Use in a Study of Human NOD2 Stimulation Activity

A flexible synthetic strategy toward the preparation of diverse N‐substituted muramyl dipeptides (N‐substituted MDPs) from different protected monosaccharides is described. The synthetic MDPs include N‐acetyl MDP and N‐glycolyl MDP, known NOD2 ligands, and this methodology allows for structural variation at six positions, including the muramic acid, peptide, and N‐substituted moieties. The capacity of these molecules to activate human NOD2 in the innate immune response was also investigated. It was found that addition of the methyl group at the C1 position of N‐glycolyl MDP significantly enhanced the NOD2 stimulating activity.