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"You, Wei"
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Enhancement of growth and salt tolerance of tomato seedlings by a natural halotolerant actinobacterium Glutamicibacter halophytocola KLBMP 5180 isolated from a coastal halophyte
Background and aims
Soil salinity stress affects the health and growth of crops. The use of plant growth-promoting rhizobacteria (PGPR) to improve the salt tolerance of plants is gaining acceptance worldwide. Here, a halotolerant, plant growth-promoting actinobacterium
Glutamicibacter halophytocola
KLBMP 5180, recently isolated from the root of a coastal halophyte
Limonium sinense
, was investigated for its capacity on the growth of tomato seedlings under the condition of saline stress.
Methods
Tomato seedlings were inoculated with strain KLBMP 5180 and irrigated with 2% NaCl salt-stress treatment. Plant growth and physiological responses were determined after harvest. The genome of strain KLBMP 5180 was sequenced and analyzed.
Results
High salinity significantly reduced the growth and biomass of tomato seedlings. However, KLBMP 5180 inoculation significantly improved tomato growth in terms of seedling fresh weight and height, root length and fresh weight, and number of fibrous roots, along with increased osmolyte content (proline) and antioxidant defense enzymes and regulation of ion homeostasis under salt stress. From the genome, we identified a series of genes that may contribute to plant growth promotion, including genes for nitrogen fixation, biosynthesis of siderophores and exopolysaccharides. Additionally, several genes related to high salinity tolerance, such as Na
+
/H
+
antiporter, K
+
transporter, glycine-betaine synthesis and transport, and several heavy metal resistance and biodegradation genes were also identified in the genome of strain KLBMP 5180
.
Conclusion
Our results demonstrate that the halotolerant strain KLBMP 5180 can be used to improve tomato seedling growth in saline soil and act as a potential agricultural biofertilizer agent in future applications.
Journal Article
Effect of Helicobacter pylori on gastrointestinal microbiota: a population-based study in Linqu, a high-risk area of gastric cancer
ObjectiveGastrointestinal microbiota may be involved in Helicobacter pylori-associated gastric cancer development. The aim of this study was to explore the possible microbial mechanisms in gastric carcinogenesis and potential dysbiosis arising from H. pylori infection.DesignDeep sequencing of the microbial 16S ribosomal RNA gene was used to investigate alterations in paired gastric biopsies and stool samples in 58 subjects with successful and 57 subjects with failed anti-H. pylori treatment, relative to 49 H. pylori negative subjects.ResultsIn H. pylori positive subjects, richness and Shannon indexes increased significantly (both p<0.001) after successful eradication and showed no difference to those of negative subjects (p=0.493 for richness and p=0.420 for Shannon index). Differential taxa analysis identified 18 significantly altered gastric genera after eradication. The combination of these genera into a Microbial Dysbiosis Index revealed that the dysbiotic microbiota in H. pylori positive mucosa was associated with advanced gastric lesions (chronic atrophic gastritis and intestinal metaplasia/dysplasia) and could be reversed by eradication. Strong coexcluding interactions between Helicobacter and Fusobacterium, Neisseria, Prevotella, Veillonella, Rothia were found only in advanced gastric lesion patients, and were absent in normal/superficial gastritis group. Changes in faecal microbiota included increased Bifidobacterium after successful H. pylori eradication and more upregulated drug-resistant functional orthologs after failed treatment.Conclusion H. pylori infection contributes significantly to gastric microbial dysbiosis that may be involved in carcinogenesis. Successful H. pylori eradication potentially restores gastric microbiota to a similar status as found in uninfected individuals, and shows beneficial effects on gut microbiota.
Journal Article
Influences of dielectric constant and scan rate on hysteresis effect in perovskite solar cell with simulation and experimental analyses
In this work, perovskite solar cells (PSCs) with different transport layers were fabricated to understand the hysteresis phenomenon under a series of scan rates. The experimental results show that the hysteresis phenomenon would be affected by the dielectric constant of transport layers and scan rate significantly. To explain this, a modified Poisson and drift-diffusion solver coupled with a fully time-dependent ion migration model is developed to analyze how the ion migration affects the performance and hysteresis of PSCs. The modeling results show that the most crucial factor in the hysteresis behavior is the built-in electric field of the perovskite. The non-linear hysteresis curves are demonstrated under different scan rates, and the mechanism of the hysteresis behavior is explained. Additionally, other factors contributing to the degree of hysteresis are determined to be the degree of degradation in the perovskite material, the quality of the perovskite crystal, and the materials of the transport layer, which corresponds to the total ion density, carrier lifetime of perovskite, and the dielectric constant of the transport layer, respectively. Finally, it was found that the dielectric constant of the transport layer is a key factor affecting hysteresis in perovskite solar cells.
Journal Article
Status and prospects for ternary organic photovoltaics
The benefits of designing and constructing organic solar cells featuring more than a single donor and single acceptor material are discussed.
In the past few years, ternary organic solar cells (OSCs) featuring multiple donor or acceptor materials in the active layer have emerged as a promising structure to simultaneously improve all solar cell parameters compared with traditional binary OSCs. Power conversion efficiencies around 10% have been achieved for conjugated polymers in a ternary structure, showing the great potential of ternary systems. In this review, we summarize progress in developing ternary OSCs and discuss many of the designs, chemistries and mechanisms that have been investigated. We conclude by highlighting the challenges and future directions for further development in the field of ternary blend OSCs.
Journal Article
A wall-resolved large-eddy simulation of deep cavity flow in acoustic resonance
The aeroacoustic source mechanism of a deep rectangular cavity, which has an aspect ratio of $D/L=2.632$ and is subjected to a turbulent boundary layer of $\\theta /L=0.0345$ at a Mach number of 0.2, is investigated by using a high-order accurate large-eddy simulation. The primary aim of this study is to provide an improved understanding of the fluid–acoustic coupling mechanism that triggers a self-sustained acoustic resonance in a deep cavity. Various analysis methods, which include Doak's momentum potential theory that allows for the separation of hydrodynamic and acoustic components, are used to provide highly detailed investigations and findings. The vortex dynamics near the cavity opening region is investigated as the potential primary source of noise generation. In addition, the noise generation mechanism is quantitatively explained by the onset of the separation region near the downstream corner that ensues from the synchronised shear layer–wall interaction. The current work extensively focuses on the fluid–acoustic coupling mechanism, and it is found that the acoustic resonance favourably modulates the hydrodynamic fluctuation near the upstream corner of the cavity. Furthermore, the current study also suggests that nonlinear interactions between fundamental acoustic resonance and higher harmonics are plausible. Based on the discussions provided in this paper, a semi-empirical model to predict the critical free stream velocity at which a strong fluid–acoustic coupling occurs as a function of cavity geometry and inflow boundary-layer property is proposed.
Journal Article
Effects of Helicobacter pylori treatment and vitamin and garlic supplementation on gastric cancer incidence and mortality: follow-up of a randomized intervention trial
AbstractObjectiveTo assess the effects of Helicobacter pylori treatment, vitamin supplementation, and garlic supplementation in the prevention of gastric cancer.DesignBlinded randomized placebo controlled trial.SettingLinqu County, Shandong province, China.Participants3365 residents of a high risk region for gastric cancer. 2258 participants seropositive for antibodies to H pylori were randomly assigned to H pylori treatment, vitamin supplementation, garlic supplementation, or their placebos in a 2×2×2 factorial design, and 1107 H pylori seronegative participants were randomly assigned to vitamin supplementation, garlic supplementation, or their placebos in a 2×2 factorial design.InterventionsH pylori treatment with amoxicillin and omeprazole for two weeks; vitamin (C, E, and selenium) and garlic (extract and oil) supplementation for 7.3 years (1995-2003).Main outcome measuresPrimary outcomes were cumulative incidence of gastric cancer identified through scheduled gastroscopies and active clinical follow-up through 2017, and deaths due to gastric cancer ascertained from death certificates and hospital records. Secondary outcomes were associations with other cause specific deaths, including cancers or cardiovascular disease.Results151 incident cases of gastric cancer and 94 deaths from gastric cancer were identified during 1995-2017. A protective effect of H pylori treatment on gastric cancer incidence persisted 22 years post-intervention (odds ratio 0.48, 95% confidence interval 0.32 to 0.71). Incidence decreased significantly with vitamin supplementation but not with garlic supplementation (0.64, 0.46 to 0.91 and 0.81, 0.57 to 1.13, respectively). All three interventions showed significant reductions in gastric cancer mortality: fully adjusted hazard ratio for H pylori treatment was 0.62 (95% confidence interval 0.39 to 0.99), for vitamin supplementation was 0.48 (0.31 to 0.75), and for garlic supplementation was 0.66 (0.43 to 1.00). Effects of H pylori treatment on both gastric cancer incidence and mortality and of vitamin supplementation on gastric cancer mortality appeared early, but the effects of vitamin supplementation on gastric cancer incidence and of garlic supplementation only appeared later. No statistically significant associations were found between interventions and other cancers or cardiovascular disease.ConclusionsH pylori treatment for two weeks and vitamin or garlic supplementation for seven years were associated with a statistically significant reduced risk of death due to gastric cancer for more than 22 years. H pylori treatment and vitamin supplementation were also associated with a statistically significantly reduced incidence of gastric cancer.Trial registrationClinicalTrials.gov NCT00339768.
Journal Article
Integrating charge mobility, stability and stretchability within conjugated polymer films for stretchable multifunctional sensors
Conjugated polymers (CPs) are promising semiconductors for intrinsically stretchable electronic devices. Ideally, such CPs should exhibit high charge mobility, excellent stability, and high stretchability. However, converging all these desirable properties in CPs has not been achieved via molecular design and/or device engineering. This work details the design, synthesis and characterization of a random polythiophene (RP-T50) containing ~50 mol% of thiophene units with a thermocleavable tertiary ester side chain and ~50 mol% of unsubstituted thiophene units, which, upon thermocleavage of alkyl chains, shows significant improvement of charge mobility and stability. Thermal annealing a RP-T50 film coated on a stretchable polydimethylsiloxane substrate spontaneously generates wrinkling in the polymer film, which effectively enhances the stretchability of the polymer film. The wrinkled RP-T50-based stretchable sensors can effectively detect humidity, ethanol, temperature and light even under 50% uniaxial and 30% biaxial strains. Our discoveries offer new design rationale of strategically applying CPs to intrinsically stretchable electronic systems.
Conjugated polymers are promising semiconductors for stretchable electronic devices but combining important properties such as high charge mobility, stability and stretchability remains challenging. Here, the authors demonstrate the synthesis of a thiophene based semiconducting polymer with cleavable side chains which shows significant improvement of charge mobility, stability and stretchability.
Journal Article
Mechanically interlocked networks cross-linked by a molecular necklace
Molecular necklaces have attracted much research attention due to their unique topological structures. Although numerous molecular necklaces with exquisite structures have been constructed, it remains a major challenge to exploit the functions and applications associated with their fascinating architectural and dynamic characteristics. Herein, we report a class of mechanically interlocked networks (MINs) cross-linked by a molecular necklace, in which multiple crown ethers are threaded on a hexagonal metallacyclic framework to furnish a cross-linker with delicate interlocked structures. The molecular necklace cross-linker possesses multiple peculiar advantages: multivalent interactions and rigid metallacycle framework guarantee robust features of MINs while the motion and dissociation of the interlocked structures bring in notable mechanical adaptivity. Moreover, the MINs could respond to the stimuli of K
+
and Br
−
, which lead to the dethreading of crown ether and even the complete decomposition of molecular necklace, respectively, showing abundant active properties. These findings demonstrate the untapped potential of molecular necklaces as cross-linkers and open the door to extend their advanced applications in intelligent supramolecular materials.
Constructing cross-linked networks with different topologies is attractive but challenging. Here the authors present mechanically interlocked networks cross-linked by a molecular necklace whose peculiar architectural and dynamic features endow the materials with robust yet mechanically adaptive properties.
Journal Article
Manipulating Weyl quasiparticles by orbital-selective photoexcitation in WTe2
Optical control of structural and electronic properties of Weyl semimetals allows development of switchable and dissipationless topological devices at the ultrafast scale. An unexpected orbital-selective photoexcitation in type-II Weyl material WTe
2
is reported under linearly polarized light (LPL), inducing striking transitions among several topologically-distinct phases mediated by effective electron-phonon couplings. The symmetry features of atomic orbitals comprising the Weyl bands result in asymmetric electronic transitions near the Weyl points, and in turn a switchable interlayer shear motion with respect to linear light polarization, when a near-infrared laser pulse is applied. Consequently, not only annihilation of Weyl quasiparticle pairs, but also increasing separation of Weyl points can be achieved, complementing existing experimental observations. In this work, we provide a new perspective on manipulating the Weyl node singularity and coherent control of electron and lattice quantum dynamics simultaneously.
Photoexcitation in Weyl semimetals is recently reported to induce topological phase transitions useful for ultrafast switching devices. Here, the authors predict that the symmetry of the atomic orbitals comprising the Weyl bands in response to linear light polarization allows for not only annihilation but also separation of Weyl quasiparticles.
Journal Article