Transcriptomic and Metabolomic Analyses Reveal Differences in Flavonoid Pathway Gene Expression Profiles between Two Dendrobium Varieties during Vernalization.

Dendrobium (Orchidaceae, Epidendoideae) plants have flowers with a wide variety of colors that persist for a long period throughout the year. The yellow coloration of Dendrobium flowers is mainly determined by the flavonol pathway and the flavone pathway, but the relevant biosynthesis mechanisms during vernalization remain unclear. To explore the similarities and differences in flavonoid biosynthesis in different tissues during vernalization, we selected two species of Dendrobium for a flower color study: Dendrobium capillipes Rchb (which has yellow flowers) and Dendrobium nobile Lindl (which has white flowers). We collected a total of 36 samples from six tissue types and both Dendrobium species during vernalization and subjected the samples to metabolic profiling and transcriptome sequencing. A total of 31,504 differentially expressed genes (DEGs) were identified between different tissues of the two Dendrobium species by transcriptomic analysis. However, many differentially accumulated metabolites (DAMs) and DEGs were enriched not only in the general pathway of "flavonoid biosynthesis" but also in multiple subpathways of "flavone and flavonol biosynthesis". According to a combined transcriptome and metabolome analysis, Putrescine hydroxycinnamoyl transferase 1 (LOC110093422) may be the main gene responsible for the differences in flavonoid accumulation during vernalization, which is closely associated with yellow flowers. Taken together, the results of our study preliminarily revealed the metabolites responsible for and the key genes regulating flavonoid biosynthesis during vernalization. These results provide a basis for the further study of the molecular mechanism of flavonoid synthesis during vernalization.

Intense pulsed light for meibomian gland dysfunction: a systematic review and meta-analysis.

BACKGROUND: Intense pulsed light therapy (IPL) is a new method being used to treat meibomian gland dysfunction (MGD) globally. With an increasing number of studies being published, it is necessary to consider additional factors related to treatment. This review aims to investigate the efficacy and safety of IPL for the treatment of MGD. METHODS: The PubMed, EMBASE, Web of Science, Cochrane Library, Google Scholar, China National Knowledge Infrastructure (CNKI), Wanfang, VIP, and SinoMed databases were searched through February 24, 2020. Randomized clinical trials and cohort studies comparing IPL+ meibomian gland expression (MGX) or IPL alone with control groups were included. The weighted mean difference (WMD) was calculated to analyze the Ocular Surface Disease Index (OSDI) score and Standard Patient Evaluation of Eye Dryness (SPEED) score, and the standard mean difference (SMD) was calculated to analyze the tear breakup time (TBUT). Heterogeneity was quantified by the I2 statistic ranging from 0 to 100%, and a random effects model was used in this meta-analysis. All analyses were performed by RevMan 5.3. All p values were calculated by the t test, and p values were regarded as statistically significant at p < 0.05. The Cochrane Collaboration's tool for assessing risk of bias was used to identify and evaluate bias in the literature. RESULTS: Nine studies with a total of 539 patients were included. Eight studies examined TBUT, six examined OSDI scores, and four examined SPEED scores. IPL combined with MGX showed superiority regarding the TBUT (SMD 2.33, 95% CI 1.04-3.61), and OSDI scores (WMD 11.93, 95% CI - 17.10 to - 6.77), with high heterogeneity. The SPEED scores were not significantly different. CONCLUSIONS: IPL combined with MGX may be an effective and safe treatment for MGD, but it cannot improve all symptoms. IPL alone is not superior to MGX. The efficacy is also affected by the number and average frequency of treatments. The efficacy of IPL may decrease within 6 months after the last treatment, so it should be considered a long-term adjuvant therapy combined with MGX. When patients receive 3 or 4 treatments (once every 3-4 weeks), a return visit at 6 months after the last treatment is required.

Colorimetric determination of Pb2+ ions based on surface leaching of Au@Pt nanoparticles as peroxidase mimic.

We report the first use of metallic nanozyme as colorimetric probe for Pb2+ determination. The method is based on the surface leaching of Au@PtNP nanozyme by Pb2+-S2O32- ions, accompanied by a decreased catalytic activity of the metallic nanozyme. To construct this colorimetric determination, the Pt deposition onto the AuNPs was carefully investigated and other experimental factors including kind of substrate and buffer were optimized. With increasing Pb2+ concentration, the catalytic activity of the Au@PtNPs decreased gradually. As a result, the blue color at 650 nm from the oxidation of 3,3',5,5'-tetramethylbenzidine by H2O2 faded gradually. A determination limit of 3.0 nM Pb2+ with a linear range from 20 to 800 nM was obtained. The assay demonstrated negligible response to common metal ions even at elevated concentrations. This colorimetric method was applied to the determination of Pb2+ ions spiked in lake water samples, and good recoveries (96.8-105.2%) were obtained. The above results indicate the potential application of metallic nanozymes in developing robust colorimetric assays. Graphical abstract Schematic representation of the surface leaching of Au@PtNP nanozyme by Pb2+-S2O32- ions, accompanying the decreased catalytic activity of the metallic nanozyme.

Research on Strengthening Fragile Paper with Polyvinylamine.

Paper documents are an important carrier of information related to human civilization, with the reinforcement and protection of fragile paper documents being a key aspect of their protection. This research utilized amphoteric polyvinylamine polymer as a paper reinforcement agent, strengthening the Xuan paper commonly used in paper documents. Scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction spectroscopy (XRD), X-ray photoelectron spectroscopy (XPS), solid-state 13C NMR, and other analytical methods were employed to compare the physical properties, micro-morphology, crystallinity, and aging resistance of the paper before and after reinforcement. Research was conducted on the effects of reinforcement, the aging resistance, and the effects on the fiber structure. The results indicate that polyethylenimine has a filling and bridging effect between the paper fibers. After treatment with polyethylenimine, there was a significant improvement in the folding endurance and tensile strength of the paper. Additionally, the paper maintains a good mechanical strength even after undergoing dry heat and humid aging.

Reinforcement and Deacidification for a Textile Scroll Painting (AD 1881) Using the CNF and MgO Suspensions.

The scroll paintings for ancestor trees have been used to inherit the spirit of ancestor worship as a historical record of family development since the late Ming Dynasty in China. A severely degraded scroll painting of an ancestor tree (made of cotton textiles) needs intervention and conservation treatment to mitigate further deterioration. On the basis of the previously reported characterization results for the painting, in this paper, a suspension that is composed of 0.6% cellulose nanofibril (CNF) and nanosized 0.15% MgO in aqueous solvent (denoted as the CNF-MgO susairpension) was prepared. Conventional characterization methods were used to assess the properties of model samples before and after treatment with the CNF-MgO suspension, as well as before and after degradation under two sets of conditions. The results show that the treated model samples are slightly alkaline, given the deposit of alkaline particles, and demonstrate good mechanical properties before and after degradation due to the increase in fiber-to-fiber bond and mitigation of acid-catalyzed hydrolysis. In spite of the non-transparency of CNF and MgO nanoparticles, they have little impact on the optical properties of textiles, as verified by transmittance data and the determination of color changes. This suspension was then used to reinforce and restore the scroll painting in a practical conservation process. The application of CNF and MgO nanoparticles on textile objects investigated in this study would expand our understanding of the conservation of such objects, especially for those that have already become acidic and degraded.

Enhanced field emission from H2 plasma-treated alpha-Fe2O3 nanowires.

Hematite (alpha-Fe2O3) nanowires were synthesized by the thermal oxidation of Fe-Ni alloy grids at 900 degrees C. The effects of hydrogen (H2) plasmas on the morphology and field emission properties of hematite (alpha-Fe2O3) nanowires were investigated. Many nanocrystallites with sharp tips were found to be produced on the surface of the originally smooth nanowires after H2 plasmas treatment. Field emission measurements demonstrated that the treated alpha-Fe2O3 nanowires possessed much better performance with turn-on field of approximately 3.7 V/microm at 0.1 microA/cm2 of current density, compared with the as-grown samples.

Growth and optical properties of sallow-like hierarchical SnO2 nanostructures.

Novel self-organized hierarchical SnO2 nanostructures have been successfully prepared by vapor phase transport with the assistance of a stainless-steel grid at 950 degrees C. Scanning electron microscopy shows that the synthesized product displays interesting sallow-like morphology, in which numerous secondary branches (beak-like nanowires) are grown randomly around the main stems (microwires). Transmission electron microscopy analysis indicates that the branches grow along a direction of [100] and the beak is formed with the growth direction switching to [110]. A room temperature photoluminescence spectrum of the present SnO2 nanostructures shows a strong emission at 572 and 604 nm(-1).

Growth, photoluminescence, and field emission of hierarchical ZnO nanostructures.

Hierarchical ZnO nanostructures with the morphology of sleeve-fishes have been fabricated on Si substrate through vapor phase transport at 850 degrees C. Studies find that each nansleeve-fish is composed of a screw-shaped microrod and some tapering nanowires grown on the microrod, all of which grow along the [0001] direction. Photoluminescence spectra exhibits strong UV emission around 385 nm without any green emissions detected, indicating that the high-quality ZnO nanostructures with low level of oxygen vacancies are obtained in our experiment. Field-emission measurements on the nanosleeve-fishes show a turn-on field as low as 2.2 V/microm at a current density of 0.1 microA/cm(2) with a anode-sample separation of 600 microm, and the emission current density reached 1 mA/cm(2) at an applied field of about 5.8 V/microm. The excellent field emission properties from such kind of nanostructures make them promising candidates for further applications in FE microelectronic devices.