Thermoelectric technology enables the harvest of waste heat and its direct conversion into electricity. The conversion efficiency is determined by the materials figure of merit
Here we show a maximum
...of ~2.8 ± 0.5 at 773 kelvin in n-type tin selenide (SnSe) crystals out of plane. The thermal conductivity in layered SnSe crystals is the lowest in the out-of-plane direction two-dimensional (2D) phonon transport. We doped SnSe with bromine to make n-type SnSe crystals with the overlapping interlayer charge density (3D charge transport). A continuous phase transition increases the symmetry and diverges two converged conduction bands. These two factors improve carrier mobility, while preserving a large Seebeck coefficient. Our findings can be applied in 2D layered materials and provide a new strategy to enhance out-of-plane electrical transport properties without degrading thermal properties.
Summary
Golgi is a critical compartment for both the reutilisation of the essential micronutrient manganese (Mn) and its detoxification. However, whether Mn plays a role in the Golgi remains to be ...demonstrated in plants.
We characterised the function of PML3, a member of the Unknown Protein Family UPF0016, in Mn transport and the regulation of plant growth, Golgi glycosylation and cell wall biosynthesis in Arabidopsis. We also investigated the relationship of PML3 with NRAMP2, a trans‐Golgi network localised Mn transporter.
PML3‐GFP is preferentially localised in the cis‐Golgi. PML3 can transport Mn to rescue the hypersensitivity of yeast mutant Δpmr1 to excess Mn. Two mutant alleles of PML3 displayed reduced plant growth and impaired seed development under Mn‐deficient conditions. The pml3 mutants also showed impaired Golgi glycosylation and cell wall biosynthesis under Mn deficiency. Double mutations of PML3 and NRAMP2 showed improved plant growth compared with that of single mutants under Mn deficiency, implying that PML3 and NRAMP2 play opposite roles in the regulation of Golgi Mn levels.
Our results suggest that PML3 mediates Mn uptake into the Golgi compartments, which is required for proper protein glycosylation and cell wall biosynthesis under Mn‐deficient conditions.
See also the Commentary on this article by Thomine & Merlot, 231: 2107–2109.
Rice is a major source of cadmium (Cd) intake for Asian people. Indica rice usually accumulates more Cd in shoots and grains than Japonica rice. However, underlying genetic bases for differential Cd ...accumulation between Indica and Japonica rice are still unknown. In this study, we cloned a quantitative trait locus (QTL) grain Cd concentration on chromosome 7 (GCC7) responsible for differential grain Cd accumulation between two rice varieties by performing QTL analysis and map‐based cloning. We found that the two GCC7 alleles, GCC7PA64s and GCC793‐11, had different promoter activity of OsHMA3, leading to different OsHMA3 expression and different shoot and grain Cd concentrations. By analyzing the distribution of different haplotypes of GCC7 among diverse rice accessions, we discovered that the high and low Cd accumulation alleles, namely GCC793‐11 and GCC7PA64s, were preferentially distributed in Indica and Japonica rice, respectively. We further showed that the GCC7PA64s allele can be used to replace the GCC793‐11 allele in the super cultivar 93‐11 to reduce grain Cd concentration without adverse effect on agronomic traits. Our results thus reveal that the QTL GCC7 with sequence variation in the OsHMA3 promoter is an important determinant controlling differential grain Cd accumulation between Indica and Japonica rice.
Indica rice usually accumulates more Cd in shoots and grains than Japonica rice. However, the underlying mechanisms are unknown. Here, we show that natural variation in the OsHMA3 promoter influences OsHMA3 expression and Cd accumulation subsequently, implying that it is an important factor determining differential Cd accumulation between Indica and Japonica rice cultivars.
Upland forests are traditionally thought to be net sinks for atmospheric methane (CH4). In such forests, in situ CH4 fluxes on tree trunks have been neglected relative to soil and canopy fluxes.
We ...measured in situ CH4 fluxes from the trunks of living trees and other surfaces, such as twigs and soils, using a static closed-chamber method, and estimated the CH4 budget in a temperate upland forest in Beijing.
We found that the trunks of Populus davidiana emitted large quantities of CH4 during July 2014–July 2015, amounting to mean annual emissions of 85.3 and 103.1 μg m−2 h−1 on a trunk surface area basis on two replicate plots. The emission rates were similar in magnitude to those from tree trunks in wetland forests. The emitted CH4 was derived from the heartwood of trunks. On a plot or ecosystem scale, trunk CH4 emissions were equivalent to c. 30–90% of the amount of CH4 consumed by soils throughout the year, with an annual average of 63%.
Our findings suggest that wet heartwoods, regardless of rot or not, occur widely in living trees on various habitats, where CH4 can be produced.
Increasing plant diversity can increase ecosystem functioning, stability, and services in both natural and managed grasslands, but the effects of herbivore diversity, and especially of livestock ...diversity, remain underexplored. Given that managed grazing is the most extensive land use worldwide, and that land managers can readily change livestock diversity, we experimentally tested how livestock diversification (sheep, cattle, or both) influenced multidiversity (the diversity of plants, insects, soil microbes, and nematodes) and ecosystem multifunctionality (including plant biomass production, plant leaf N and P, above-ground insect abundance, nutrient cycling, soil C stocks, water regulation, and plant–microbe symbiosis) in the world’s largest remaining grassland. We also considered the potential dependence of ecosystem multifunctionality on multidiversity. We found that livestock diversification substantially increased ecosystem multifunctionality by increasing multidiversity. The link between multidiversity and ecosystem multifunctionality was always stronger than the link between single diversity components and functions. Our work provides insights into the importance of multitrophic diversity to maintain multifunctionality in managed ecosystems and suggests that diversifying livestock could promote both multidiversity and ecosystem multifunctionality in an increasingly managed world.
Summary
Previous studies revealed that the promoters for driving both Cas9 and sgRNAs are quite important for efficient genome editing by CRISPR/Cas9 in plants. Here, we report our results of ...targeted genome editing using the maize dmc1 gene promoter combined with the U3 promoter for Cas9 and sgRNA, respectively. Three loci in the maize genome were selected for targeting. The T0 plants regenerated were highly efficiently edited at the target sites with homozygous or bi‐allelic mutants accounting for about 66%. The mutations in T0 plants could be stably transmitted to the T1 generation, and new mutations could be generated in gametes or zygotes. Whole‐genome resequencing indicated that no off‐target mutations could be detected in the predicted loci with sequence similarity to the targeted site. Our results show that the dmc1 promoter‐controlled (DPC) CRISPR/Cas9 system is highly efficient in maize and provide further evidence that the optimization of the promoters used for the CRISPR/Cas9 system is important for enhancing the efficiency of targeted genome editing in plants. The evolutionary conservation of the dmc1 gene suggests its potential for use in other plant species.
Cadmium (Cd) intake is harmful to human health and Cd contamination in rice grains represents a severe threat to those consuming rice as a staple food.Knockout of Cd transporters is a promising ...strategy to reduce Cd accumulation in rice grains.OsNRAMP5 is the major transporter for Cd and manganese (Mn) uptake in rice.Nevertheless,it is uncertain whether knockout of OsNRAMP5 is applicable to produce low Cd rice without affecting plant growth and grain yield.In this study,we adopted CRISPR/Cas9-based gene editing technology to knock out OsNRAMP5 in two japonica varieties.We generated three independent transgene-free osnramp5 mutants and investigated the effect of osnramp5 mutations on Cd accumulation and plant growth.Hydroponic experiments showed that plant growth and chlorophyll content were significantly reduced in osnramp5 mutants at low Mn conditions,and this defective growth in the mutants could be fully rescued by supply of high levels of Mn.Cd and Mn accumulation in both roots and shoots was markedly reduced in the mutants compared to that in wild-type plants.In paddy field experiments,although Cd in flag leaves and grains was greatly reduced in osnramp5 mutants,some agronomic traits including plant height,seed setting rate,and grain number per panicle were affected in the mutants,which ultimately caused a mild reduction in grain yield.The reduced plant growth in the mutants can be attributed to a marked decrease in Mn accumulation.Our results reveal that the manipulation of OsNRAMP5 should be treated with caution:When assessing the applicability of osnramp5 mutants,soil pH and soil water content in paddy fields need to be taken into consideration,since they might affect the levels of available Mn in the soil and consequently determine the effect of the mutation on grain yield.
Uncontrolled hemorrhage is the main reason of possible preventable death after accidental injury. It is necessary to develop a hemostatic agent with rapid hemostatic performance and good ...biocompatibility. In this study, a chitosan/diatom‐biosilica‐based aerogel is developed using dopamine as cross‐linker by simple alkaline precipitation and tert‐butyl alcohol replacement. The chitosan/diatom‐biosilica aerogel exhibits favorable biocompatibility and multiscale hierarchical porous structure (from nanometer to micrometer), which can be controlled by the concentration of tert‐butyl alcohol. The displacement of tert‐butyl alcohol can keep the porosity of diatom‐biosilica in aerogel and give it large surface with efficient water absorption ratio. 30% tert‐butyl alcohol replacement of aerogel possesses the largest surface area (74.441 m2 g−1), water absorption capacity (316.83 ± 2.04%), and excellent hemostatic performance in vitro blood coagulation (≈70 s). Furthermore, this aerogel exhibits the shortest clotting time and lowest blood loss in rat hemorrhage model. The strong interface effect between aerogel and blood is able to promote erythrocytes aggregation, platelets adhesion, and activation, as well as, activate the intrinsic coagulation pathway to accelerate blood coagulation. All the above results demonstrate that chitosan/diatom‐biosilica aerogel has great potential to be a safe and rapid hemostatic material.
A chitosan, diatom‐biosilica, and dopamine‐based porous aerogel is developed using simple alkaline precipitation and solvent replacement strategy. Benefiting from function of the porous structure and functional groups, the developed aerogel has great potential to be a safe and rapid hemostatic material for pre‐hospital emergency treatments to reduce mortality due to uncontrolled hemorrhage.
Optically active β‐amino alcohols are very useful chiral intermediates frequently used in the preparation of pharmaceutically active substances. Here, a novel cyclohexylamine oxidase (ArCHAO) was ...identified from the genome sequence of Arthrobacter sp. TYUT010‐15 with the R‐stereoselective deamination activity of β‐amino alcohol. ArCHAO was cloned and successfully expressed in E. coli BL21, purified and characterized. Substrate‐specific analysis revealed that ArCHAO has high activity (4.15 to 6.34 U mg−1 protein) and excellent enantioselectivity toward the tested β‐amino alcohols. By using purified ArCHAO, a wide range of racemic β‐amino alcohols were resolved, (S)‐β‐amino alcohols were obtained in >99 % ee. Deracemization of racemic β‐amino alcohols was conducted by ArCHAO‐catalyzed enantioselective deamination and transaminase‐catalyzed enantioselective amination to afford (S)‐β‐amino alcohols in excellent conversion (78–94 %) and enantiomeric excess (>99 %). Preparative‐scale deracemization was carried out with 50 mM (6.859 g L−1) racemic 2‐amino‐2‐phenylethanol, (S)‐2‐amino‐2‐phenylethanol was obtained in 75 % isolated yield and >99 % ee.
Coming to a resolution: Enantioselective cascade biocatalysis for deracemization of racemic β‐amino alcohols was conducted by employing cyclohexylamine oxidase and ω‐transaminase. (S)‐β‐amino alcohols were obtained in excellent conversions and ee values.
MnOOH nanowires decorated with NiAl-LDH have been successfully prepared via in-situ growth of small NiAl-LDH nanosheets by hydrothermal method without using any organic reagents. The morphology and ...structure of the samples were characterized by a series of techniques, including scanning electron microscope (SEM), transmission electron microscope (TEM), X-ray diffractometer (XRD), X-ray photoelectron spectroscopy (XPS), thermogravimetric analysis meter (TGA), Brunauer-Emmett-Teller (BET), and Fourier transform infrared spectrometer (FT-IR). The excellent electrochemical properties of the as-prepared products were obtained by cyclic voltammetry (CV), galvanostatic charge-discharge (GCD) and electrochemical impedance spectroscopy (EIS). The specific capacitance was 1331.11 F/g at current density of 1 A/g in 6 M of KOH electrolyte and still could keep good cycling stability after 1000 cycles. An asymmetric supercapacitor (ASC) was assembled by MnOOH/NiAl-LDH and activated carbon (AC), exhibited excellent electrochemical performances in energy storage. At a power density of 800 W/kg, the equipment could deliver a maximum energy density of 26.89 Wh/kg and maintain good cycling stability. The excellent results suggested that MnOOH/NiAl-LDH nanocomposite could be used as a promising material for supercapacitors.
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•MnOOH nanowires decorated with small NiAl-LDH nanosheets were successfully obtained.•The as-prepared nanocomposite displays an excellent electrochemical performance.•These materials can used as electrode for high-performance supercapacitors.
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