Phase formation,microstructure and electrical properties of mica glass-ceramics containing Cr2O3 produced by heat treatment

The mica glass-ceramics containing Cr₂O₃ were produced via heat treatment process from the bulk parent glass specimens. The appropriate treatment temperatures were selected according to the information provided by the DTA measurement. XRD analysis demonstrated that co-existence of the mica and MgAl₂Si₃O₁₀ phases were found at the lower treatment temperature while pure mica phase could be formed at a higher temperature. The SEM investigations revealed the effect of Cr₂O₃ addition on mica crystals development. The electrical resistivity of the glass-ceramic samples showed some significant relation with the added ions. With small amount of addition, an increase of the electrical resistivity was observed. The present glass-ceramics could be a promising candidate as advanced insulating materials, as evidenced from the presence of crystalline phases with machinable properties and good mechanical strength coupled with its high resistivity.     

Haplotype Analysis of BADH1 by Next-Generation Sequencing Reveals Association with Salt Tolerance in Rice during Domestication

Betaine aldehyde dehydrogenase 1 (BADH1), a paralog of the fragrance gene BADH2, is known to be associated with salt stress through the accumulation of synthesized glycine betaine (GB), which is involved in the response to abiotic stresses. Despite the unclear association between BADH1 and salt stress, we observed the responses of eight phenotypic characteristics (germination percentage (GP), germination energy (GE), germination index (GI), mean germination time (MGT), germination rate (GR), shoot length (SL), root length (RL), and total dry weight (TDW)) to salt stress during the germination stage of 475 rice accessions to investigate their association with BADH1 haplotypes. We found a total of 116 SNPs and 77 InDels in the whole BADH1 gene region, representing 39 haplotypes. Twenty-nine haplotypes representing 27 mutated alleles (two InDels and 25 SNPs) were highly (p < 0.05) associated with salt stress, including the five SNPs that have been previously reported to be associated with salt tolerance. We observed three predominant haplotypes associated with salt tolerance, Hap_2, Hap_18, and Hap_23, which were Indica specific, indicating a comparatively high number of rice accessions among the associated haplotypes. Eight plant parameters (phenotypes) also showed clear responses to salt stress, and except for MGT (mean germination time), all were positively correlated with each other. Different signatures of domestication for BADH1 were detected in cultivated rice by identifying the highest and lowest Tajima’s D values of two major cultivated ecotypes (Temperate Japonica and Indica). Our findings on these significant associations and BADH1 evolution to plant traits can be useful for future research development related to its gene expression.     

Analysis of steel production in Thailand: Environmental impacts and solutions

Steels were the upstream of various products. The environmental performance of steel can affect those of the downstream products. In this work, environmental impacts of individual steels, i.e. slab, hot-rolled, cold-rolled, hot-dipped galvanized, and electro-galvanized steels, were studied, via life cycle assessment. The impact assessment methods of IPCC 2007 GWP 100a and Eco-indicator 99 (H) were used to cover the impact categories of Global warming potential, Fossil fuels, Ecotoxicity, Minerals, Carcinogens, and Respiratory inorganics. In all categories, the slab showed the lowest impacts and the hot-dipped galvanized steel showed the highest impacts. The main causes of the impacts were attributed to these inputs; steel, energy, and zinc. The emissions from steel production plants showed relatively low impacts. Small amount of zinc input can cause huge environmental impacts. The impacts of Fossil fuels, Minerals, and Ecotoxicity, of 1-kg zinc were 2.9, 116.9, and 39.6 times of those caused by 1-kg cold-rolled steel, respectively. The reduction of zinc consumption and the improvement of zinc production process, in terms of reduction of heavy metal emissions, could largely improve environmental performance of the galvanized steels.     

Phase formation and dielectric properties of ferroelectric glass-ceramics in Na2O-BaO-Nb2O5-SiO2 system doped with Nd3+

Ferroelectric Glass-ceramics of the Na₂O–BaO–Nb₂O₅–SiO₂ system were obtained from controlled crystallization process performed on the parent glass of composition (24-x)Na₂O-xBaO-26Nb₂O₅-50SiO₂ where x?=?4 was selected. Nd₂O₃ doping was applied in the range 0–3 mol%. X-ray diffraction analysis indicated that NaNbO₃ and NaBa₂Nb₅O₁₅ crystals formed as two main crystalline phases. Their relative intensities varied with treatment temperature. Crystalline sizes of both NaNbO₃ and NaBa₂Nb₅O₁₅ calculated from XRD peak broadening were in nanoscale range. Increasing of doping content also gave a parent glass with higher bulk density. The dielectric constant measured at room temperature for glass-ceramic samples was found to be sensitive to the presence of NaBa₂Nb₅O₁₅ phase. The results of the present work suggest that introduction of Nd³⁺ into Na₂O-BaO-Nb₂O₅-SiO₂ system not only alters the dielectric response but also changes the phase transition behaviors of the co-existant ferroelectric phases by suppressing the growth of the NaBa₂Nb₅O₁₅ crystals.     

Selection of reference genes for quantitative real‐time PCR in postharvest tomatoes (Lycopersicon esculentum) treated by continuous low‐voltage direct current electricity to increase secondary metabolites

Quantitative real‐time PCR (RT‐qPCR) is often used for gene expression analysis to reveal molecular mechanism of how stresses can enhance the secondary metabolites production. For RT‐qPCR to be valid, robust reference genes are required. This study validated nine candidate genes as reference genes using BestKeeper, NormFinder and geNorm methods in RT‐qPCR analysis of postharvest tomatoes subjected to electricity‐induced stress. The most stable genes as indicated by each method were EF‐1α by BestKeeper; CAC by NormFinder; and PP2Acs/TIP41 by geNorm. Due to the inconsistency in the ranking of the candidate genes by the three methods, the pairwise variation from geNorm analysis was used to calculate the minimum numbers of reference genes for an accurate normalisation and revealed that a combination of PP2Acs and TIP41 was an optimum. This reference gene combination was further validated for their stability in RT‐qPCR analysis of four carotenoid‐related genes, and more reliable expression levels were obtained.     

Modification of human cancellous bone using Thai silk fibroin and gelatin for enhanced osteoconductive potential

The modification of human cancellous bone (hBONE) with silk fibroin/gelatin (SF/G) using 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride (EDC)/N-hydroxysuccini-mide (NHS) crosslinking was established. The SF/G solutions at a weight ratio of 50/50 and the solution concentrations of 1, 2, and 4 wt % were studied. SF/G sub-matrix was formed on the surface and inside pore structure of hBONE. All hBONE scaffolds modified with SF/G showed smaller pore sizes, less porosity, and slightly lower compressive modulus than unmodified hBONE. SF/G sub-matrix was gradually biodegraded in collagenase solution along 4 days. The hBONE scaffolds modified with SF/G, particularly at 2 and 4 wt % solution concentrations, promoted attachment, proliferation, and osteogenic differentiation of bone marrow-derived mesenchymal stem cells (MSC), comparing to the original hBONE. The highest cell number, ALP activity and calcium production were observed for MSC cultured on the hBONE scaffolds modified with 4 wt % SF/G. The mineralization was also remarkably induced in the cases of modified hBONE scaffolds as observed from the deposited calcium phosphate by EDS. The modification of hBONE with SF/G was, therefore, the promising method to enhance the osteoconductive potential of human bone graft for bone tissue engineering.