Transcriptome Expression Profiling Reveals the Molecular Response to Salt Stress in Gossypium anomalum Seedlings.

Some wild cotton species are remarkably tolerant to salt stress, and hence represent valuable resources for improving salt tolerance of the domesticated allotetraploid species Gossypium hirsutum L. Here, we first detected salt-induced stress changes in physiological and biochemical indexes of G. anomalum, a wild African diploid cotton species. Under 350 mmol/L NaCl treatment, the photosynthetic parameters declined significantly, whereas hydrogen peroxide (H2O2) and malondialdehyde (MDA) contents increased. Catalase (CAT), superoxide dismutase (SOD), and peroxidase (POD) activity and proline (PRO) content also significantly increased, reaching peak values at different stages of salt stress. We used RNA-Seq to characterize 15,476 differentially expressed genes in G. anomalum roots after 6, 12, 24, 72, and 144 h of salt stress. Gene Ontology enrichment analysis revealed these genes to be related to sequence-specific DNA and iron ion binding and oxidoreductase, peroxidase, antioxidant, and transferase activity; meanwhile, the top enriched pathways from the Kyoto Encyclopedia of Genes and Genomes database were plant hormone signal transduction, phenylpropanoid biosynthesis, fatty acid degradation, carotenoid biosynthesis, zeatin biosynthesis, starch and sucrose metabolism, and MAPK signaling. A total of 1231 transcription factors were found to be expressed in response to salt stress, representing ERF, MYB, WRKY, NAC, C2H2, bZIP, and HD-ZIP families. Nine candidate genes were validated by quantitative real-time PCR and their expression patterns were found to be consistent with the RNA-Seq data. These data promise to significantly advance our understanding of the molecular response to salt stress in Gossypium spp., with potential value for breeding applications.

Iron-Catalyzed Alkoxyl Radical-Induced C-C Bond Cleavage/gem-Difluoroalkylation Cascade.

An inexpensive iron-catalyzed alkoxyl radical-induced C-C bond cleavage/gem-difluoroalkylation cascade is presented. Regulated by the structure of alkoxyl radical precursors, fluorinated distal diketones were synthesized through a ring-opening strategy and difluoroalkylated medium-sized lactones and macrolactones were constructed via a ring-expansion strategy. Both protocols proceeded under mild and redox neutral conditions with a broad substrate scope and good functional group compatibility.

Highly accurate particulate matter detection assisted by an air heater based on a silver nanowire film.

Recently, many studies have been carried out to solve the particulate matter pollution problem. However, the detection accuracy for particulate matter in the atmosphere remains unsatisfactory due to the influence of the air relative humidity. Herein, we report a Ag nanowire film air heater to enhance the detection accuracy through internal heating. From air temperature and air relative humidity relationship analysis, it has been found that the Ag nanowire film air heater can form the most suitable air relative humidity in the detection system, thereby enhancing the detection accuracy. Consequently, the Ag nanowire film air heater-assisted light scattering particulate matter detector has achieved tremendous enhancement in its detection accuracy, which is comparable with the data obtained by the beta gauge method. Film resistance plays a key role in internal air temperature distribution and the resultant air relative humidity at given voltages. To achieve the most suitable air relative humidity for continuous online monitoring, response time and power consumption should be balanced. Therefore, guidance for designing Ag nanowire films with proper resistance used in an optional-sized detector has been given for quick response, high accuracy and low power consumption. This work is of significance for providing insight for future studies in particulate matter detection and pollution remediation.

Sandwich-Structured Silver Nanowire Transparent Conductive Films with 3H Hardness and Robust Flexibility for Potential Applications in Curved Touch Screens.

A sandwich-structured bottom hard-coat/silver nanowire/top hard-coat (BHC/AgNW/THC) transparent conductive film (TCF) has been prepared by embedding the functional AgNW layer between two HC layers. The BHC/AgNW/THC TCFs show high scratch resistance with a hardness of 3H due to the enhanced adhesion to the substrate. In addition, the BHC/AgNW/THC TCFs exhibit a transmittance of 90.6% and a haze of 1% at 550 nm under a sheet resistance of 72 Ω/sq. Furthermore, highly enhanced long-term stability has been guaranteed by the HC layers due to their excellent gas barrier property. The amazing fact is that hard coating has little effect on the flexibility of AgNW films especially under extreme bending conditions and negligible resistance change could be observed after bending over thousands of times. Consequently, the greatly improved performance of BHC/AgNW/THC TCFs provided by employing hard coating layers paves the way for real-world applications of flexible AgNWs in vast areas that rigid indium tin oxide is not suitable.

Tackling the Stability Issues of Silver Nanowire Transparent Conductive Films through FeCl3 Dilute Solution Treatment.

Silver nanowires (AgNWs) have been investigated as alternatives to indium tin oxide in transparent conductive films (TCFs) for electronics. However, AgNW TCFs still pose stability issues when exposed to thermal, chemical, and mechanical stimuli. Herein, we demonstrate a facile and effective route to improve stability by treating the films with dilute ferric chloride solution. Our results indicate that after treatment the films exhibit a dramatically enhanced stability against aging, high temperature oxidation, chemical etching, sulfurization, and mechanical straining. Size-dependent instability is fully explored and explained regarding surface atomic diffusion, which could be blocked by enhancing the activation energy of surface diffusion through forming a AgCl cap under ferric chloride solution treatment. Chemisorption-related Fermi level shift of silver nanowires is applied to tune their chemical reactivity to ferric chloride solution for balancing between size-dependent stability improvement and maintaining optoelectrical properties. Owing to the dilute treatment solution, the treated films exhibit a negligible change in light transmittance, whereas sheet resistance decreases by 30% and flexibility increases because of capillary-force-induced welding of contacting AgNWs and AgCl layer mediated tightening. These findings are significant for real-world applications of AgNW TCFs.

[Determination of trace chrysene in environmental water by solid-phase microextraction coupled with high performance liquid chromatography].

A rapid method for the determination of trace chrysene in environmental water by solid-phase microextraction (SPME) coupled with high performmnce liquid chromatography (HPLC) was developed. The experimental conditions of SPME, such as extraction time, extraction temperature, effect of ion strength, desorption time, desorption solution, desorption mode and the analytical conditions of HPLC were optimized. The optimal conditions were room temperature, 1,100 r/min of stirring rate, 30 min of extraction time, 3 min of desorption time, and methanol as the desorption solution. Methanol was used as the mobile phase on a C18 reversed phase chromatographic column. The flow rate was 1 mL/min. The detection wavelength was 266 nm on a UV-Vis detector. The linear range was from 0.013 microgram/L to 3.0 micrograms/L, the detection limit was 2.7 ng/L, and the relative standard deviation (RSD) was 5.6%. The method was used for the determination of trace chrysene in tap water, mineral water, rain water and river water. The recoveries were from 103.2% to 119.3%, the RSDs were from 4.8% to 10.2%. The method is fast, convenient, sensitive, solvent-free, and suitable for the determination of trace chrysene in environmental water.