Exploring valid reference genes for gene expression studies in Brachypodium distachyon by real-time PCR

<p>Abstract</p> <p>Background</p> <p>The wild grass species <it>Brachypodium distachyon </it>(Brachypodium hereafter) is emerging as a new model system for grass crop genomics research and biofuel grass biology. A draft nuclear genome sequence is expected to be publicly available in the near future; an explosion of gene expression studies will undoubtedly follow. Therefore, stable reference genes are necessary to normalize the gene expression data.</p> <p>Results</p> <p>A systematic exploration of suitable reference genes in Brachypodium is presented here. Nine reference gene candidates were chosen, and their gene sequences were obtained from the Brachypodium expressed sequence tag (EST) databases. Their expression levels were examined by quantitative real-time PCR (qRT-PCR) using 21 different Brachypodium plant samples, including those from different plant tissues and grown under various growth conditions. Effects of plant growth hormones were also visualized in the assays. The expression stability of the candidate genes was evaluated using two analysis software packages, geNorm and NormFinder. In conclusion, the ubiquitin-conjugating enzyme 18 gene (<it>UBC18</it>) was validated as a suitable reference gene across all the plant samples examined. While the expression of the polyubiquitin genes (<it>Ubi4 </it>and <it>Ubi10</it>) was most stable in different plant tissues and growth hormone-treated plant samples, the expression of the S-adenosylmethionine decarboxylase gene (<it>SamDC</it>) ranked was most stable in plants grown under various environmental stresses.</p> <p>Conclusion</p> <p>This study identified the reference genes that are most suitable for normalizing the gene expression data in Brachypodium. These reference genes will be particularly useful when stress-responsive genes are analyzed in order to produce transgenic plants that exhibit enhanced stress resistance.</p

High-throughput discovery of chemical structure-polarity relationships combining automation and machine learning techniques

As an essential attribute of organic compounds, polarity has a profound influence on many molecular properties such as solubility and phase transition temperature. Thin layer chromatography (TLC) represents a commonly used technique for polarity measurement. However, current TLC analysis presents several problems, including the need for a large number of attempts to obtain suitable conditions, as well as irreproducibility due to non-standardization. Herein, we describe an automated experiment system for TLC analysis. This system is designed to conduct TLC analysis automatically, facilitating high-throughput experimentation by collecting large experimental data under standardized conditions. Using these datasets, machine learning (ML) methods are employed to construct surrogate models correlating organic compounds' structures and their polarity using retardation factor (Rf). The trained ML models are able to predict the Rf value curve of organic compounds with high accuracy. Furthermore, the constitutive relationship between the compound and its polarity can also be discovered through these modeling methods, and the underlying mechanism is rationalized through adsorption theories. The trained ML models not only reduce the need for empirical optimization currently required for TLC analysis, but also provide general guidelines for the selection of conditions, making TLC an easily accessible tool for the broad scientific community

Hydrogen effects on nanomechanical behavior of additively manufactured 316L stainless steels

Additive manufacturing (AM) has received considerable attention in recent years due to its ability to produce complex engineering components with reduced cost and waste, which simply cannot be made with conventional manufacturing processes. It has been reported that AM 316L austenitic stainless steel (SS) has excellent mechanical properties and possibly even breaks the strength-ductility trade-off. For practical industrial application, it is necessary to investigate the AM steel\u27s resistance to hydrogen embrittlement which is unavoidable in most strucral applications. In this work, we explore the hydrogen effects on nanomechanical responses of AM 316L SS (such as hardness, strain rate sensitivity, activation volume). The obtained results will be compared with those of conventional 316L SS and discussed in terms of hydrogen effect on plastic deformation and microstructure. Please click Additional Files below to see the full abstract

A randomized, open-label study comparing low-dose clevudine plus adefovir combination therapy with clevudine monotherapy in naïve chronic hepatitis B patients

PURPOSE: Clevudine 30 mg showed potent antiviral activity with a marked post-treatment antiviral effect. However, long-term treatment with clevudine monotherapy induced resistance and myopathy in some cases. The objective of this study is to evaluate the preliminary efficacy and safety of the combination of clevudine 20 mg and adefovir compared to clevudine monotherapy. METHODS: Seventy-four patients were randomized to either a combination of clevudine 20 mg and adefovir or clevudine 20 or 30 mg and were treated for 2 years. The viral kinetics for 24 weeks, virological response [VR; hepatitis B virus (HBV) DNA less than 300 copies/ml], and the biochemical response [BR; normal alanine aminotransferase (ALT)] were assessed. RESULTS: There was no difference in baseline characteristics among the three groups. Viral kinetics study showed no statistically significant difference among them during 24 weeks. The combination group showed 95 % virological response with a statistically significant difference compared to the clevudine 30 mg (67 %) and 20 mg (71 %) groups (p = 0.0376). Biochemical response rates were similar in all groups (78–94 %). No resistance was reported in the combination group, while 20 % of patients treated with clevudine 30 mg or 20 mg reported resistance during 2 years. Muscle-related symptoms such as myalgia (1 in clevudine 30 mg, 1 in the combination group) and muscle weakness (1 in clevudine 30 mg, 2 in clevudine 20 mg) were reported in five patients (7 %); of these, three patients discontinued the study. CONCLUSION: We concluded that the combination of clevudine 20 mg and adefovir produced a potent antiviral response together with a good resistance profile compared to clevudine monotherapy at 96 weeks in this pilot study

Ultrathin titania coating for high-temperature stable SiO2/Pt nanocatalysts

The facile synthesis of silica supported platinum nanoparticles with ultrathin titania coating to enhance metal-support interactions suitable for high temperature reactions is reported, as thermal and structure stability of metal nanoparticles is important for catalytic reactions.close8