The synergy of photothermal energy and optical forces generated by tightly focused laser beams can be used to transform the shape of gold nanoparticles. Here, the combination of these two effects is ...demonstrated to be an effective way of elongating gold nanoparticles (Au NPs), massively tuning their plasmonic properties. The photothermal effect of the laser increases the temperature of Au NPs above the melting point, and optical forces deform the molten Au NPs. As a result, the shape of Au NPs transforms from nanospheres into nanorods or dimers, depending on the power and time of irradiation as well as the surface energy of the substrate. This process is reversible by using high laser power to transform nanorods back to nanospheres due to capillary dewetting. Such light-induced transformations of nanostructures not only provide a facile way to tune plasmon resonances but also shed light on how the synergistic effect of photothermal energy and optical forces works on plasmonic nanoparticles.
Chirality is pivotal in nature which attracts wide research interests from all disciplines and creating chiral matter is one of the central themes for chemists and material scientists. Despite of ...significant efforts, a simple, cost-effective and general method that can produce different kinds of chiral metamaterials with high regularity and tailorability is still demanding but greatly missing. Here, we introduce polarization-directed growth of spiral nanostructures via vector beams, which is simple, tailorable and generally applicable to both plasmonic and dielectric materials. The self-aligned near field enhances the photochemical growth along the polarization, which is crucial for the oriented growth. The obtained plasmonic chiral nanostructures present prominent optical activity with a g-factor up to 0.4, which can be tuned by adjusting the spirality of the vector beams. These spiral plasmonic nanostructures can be used for the sensing of different chiral enantiomers. The dielectric chiral metasurfaces can also be formed in arrays of sub-mm scale, which exhibit a g-factor over 0.1. However, photoluminescence of chiral cadmium sulfide presents a very weak luminescence g-factor with the excitation of linearly polarized light. A number of applications can be envisioned with these chiral nanostructures such as chiral sensing, chiral separation and chiral information storage.
Low availability of nitrogen (N) is often a major limiting factor to crop yield in most nutrient-poor soils. Arbuscular mycorrhizal (AM) fungi are beneficial symbionts of most land plants that ...enhance plant nutrient uptake, particularly of phosphate. A growing number of reports point to the substantially increased N accumulation in many mycorrhizal plants; however, the contribution of AM symbiosis to plant N nutrition and the mechanisms underlying the AM-mediated N acquisition are still in the early stages of being understood. Here, we report that inoculation with AM fungus Rhizophagus irregularis remarkably promoted rice (Oryza sativa) growth and N acquisition, and about 42% of the overall N acquired by rice roots could be delivered via the symbiotic route under N-NO₃⁻ supply condition. Mycorrhizal colonization strongly induced expression of the putative nitrate transporter gene OsNPF4.5 in rice roots, and its orthologs ZmNPF4.5 in Zea mays and SbNPF4.5 in Sorghum bicolor. OsNPF4.5 is exclusively expressed in the cells containing arbuscules and displayed a low-affinity NO₃⁻ transport activity when expressed in Xenopus laevis oocytes. Moreover, knockout of OsNPF4.5 resulted in a 45% decrease in symbiotic N uptake and a significant reduction in arbuscule incidence when NO₃⁻ was supplied as an N source. Based on our results, we propose that the NPF4.5 plays a key role in mycorrhizal NO₃⁻ acquisition, a symbiotic N uptake route that might be highly conserved in gramineous species.
Display omitted
•Polymeric adsorbents with well-developed micro-mesopore were prepared.•High BJH surface area can enhance adsorption of medium–high concentration of VOCs.•Mesopores near to macropores ...make very limited contribution to VOCs adsorption.•Mesopore can effectively improve the desorption efficiency.
To enhance adsorption and desorption efficiency of volatile organic compounds from gas streams, we synthesized a series of well-developed micro-mesoporous hypercrosslinked polymeric adsorbents (MM-1, MM-2, and MM-3). The adsorption and desorption performance of dichloromethane and 2-butanone on newly synthesized adsorbents was investigated and compared with commercial micropore-dominated hypercrosslinked polymeric adsorbent (JT-001). The contributions of micropore and mesopore to adsorption and desorption of dichloromethane and 2-butanone on polymeric adsorbents were well elucidated. Consequently, the adsorbent MM-3 had been sorted out with high BET surface area (1606m2/g), large micropore and mesopore volumes (0.562mL/g and 1.046mL/g, respectively). The MM-3 exhibited the similar adsorption capacities with JT-001 for dichloromethane and 2-butanone at regions of p/p0<0.2, but had higher adsorption capacities than JT-001 at high relative pressures. The largest adsorption capacities of MM-3 for dichloromethane and 2-butanone at 308K were 1345.3mg/g and 853.5mg/g, respectively, which are about 1.78 and 1.88 times those of JT-001 under the same condition. Furthermore, the MM-3 exhibited higher desorption efficiencies than JT-001, especially for 2-butanone with a higher boiling point.
Grain weight (GW) is one of the component traits of wheat yield. Existing reports have shown that multiple phytohormones are involved in the regulation of GW in different crops. However, the ...potential role of jasmonic acid (JA) remains unclear. Here, we report that triticale grain weight 1 (tgw1) mutant, with marked reductions in both GW and JA content, is caused by a premature stop mutation in keto-acyl thiolase 2B (KAT-2B) involved in β-oxidation during JA synthesis. KAT-2B overexpression increases GW in wild type and boosts yield. Additionally, KAT-2B compliments the grain defect in tgw1 and rescues the lethal phenotype of the Arabidopsis kat2 mutant in a sucrose-free medium. Despite the suppression of JA synthesis in tgw1 mutant, ABA synthesis is upregulated, which is accompanied by enhanced expression of SAG3 and reduction of chlorophyll content in leaves. Together, these results demonstrate a role of the JA synthetic gene KAT-2B in controlling GW and its potential application value for wheat improvement.
Tumor-associated macrophage (TAM), a crucial component of immune cell infiltrated in tumor microenvironment, is associated with progression of oral squamous cell carcinoma (OSCC). However, it is ...still unclear how TAM is induced/accumulated and activated around/in OSCC. In the study herein, we tried to understand how TAM accumulates and activates in the OSCC and how TAM promotes OSCC to convert cancer stem cell (CSC). In this study, first important finding was that the M2 macrophages significantly increased in all twenty human OSCC samples in vivo. Cancer-associated fibroblast (CAF)-derived CXCL12 effectively attracted monocytes, which displayed M2 macrophage phenotype. Blocking CXCL12 receptor (CXCR4) significantly reduced chemotaxis of M2 macrophage. Polarized M2 macrophage promoted CSC-like transition in OSCC cell line, Cal27 cells. These CSC-like cells significantly expressed higher Sox2, Oct4, and Nanog genes, were stronger positive for CD44 and CD105, increased cell proliferation with less apoptosis, enhanced cell migration, and were resistant to chemotherapy drug, vineristine. These results indicate that CAF effectively attracts monocytes via the CXCL12/CXCR4 pathway and induces their differentiation to M2 macrophages. Interestingly, these polarized M2 macrophages promote formation of CSC-like cells from the OSCC lead to enhance OSCC proliferation with less apoptosis. Therefore, our findings have potential to lead to novel therapy for the OSCC to target CXCL12-mediated TAM recruitment.
SIRT3 is an NAD
-dependent deacetylase in the mitochondria with an extensive ability to regulate mitochondrial morphology and function. It has been reported that SIRT3 participates in the occurrence ...and development of many aging-related diseases. Osteoporosis is a common aging-related disease characterized by decreased bone mass and fragility fractures, which has caused a huge burden on society. Current research shows that SIRT3 is involved in the physiological processes of senescence of bone marrow mesenchymal stem cells (BMSCs), differentiation of BMSCs and osteoclasts. However, the specific effects and mechanisms of SIRT3 in osteoporosis are not clear. In the current review, we elaborated on the physiological functions of SIRT3, the cell types involved in bone remodeling, and the role of SIRT3 in osteoporosis. Furthermore, it also provided a theoretical basis for SIRT3 as a therapeutic target for osteoporosis.
Most terrestrial plants are able to form a root symbiosis with arbuscular mycorrhizal (AM) fungi for enhancing the assimilation of mineral nutrients. AM fungi are obligate symbionts that depend on ...host plants as their sole carbon source. Development of an AM association requires a continuous signal exchange between the two symbionts, which triggers coordinated differentiation of both partners, to enable their interaction within the root cells. The control of the AM symbiosis involves a finely-tuned process, and an increasing number of studies have pointed to a pivotal role of several phytohormones, such as strigolactones (SLs), gibberellic acids (GAs), and auxin, in the modulation of AM symbiosis, through the early recognition of events up to the final arbuscular formation. SLs are involved in the presymbiotic growth of the fungus, while auxin is required for both the early steps of fungal growth and the differentiation of arbuscules. GAs modulate arbuscule formation in a dose-dependent manner, via DELLA proteins, a group of GRAS transcription factors that negatively control the GA signaling. Here, we summarize the recent findings on the roles of these plant hormones in AM symbiosis, and also explore the current understanding of how the DELLA proteins act as central regulators to coordinate plant hormone signaling, to regulate the AM symbiosis.
Plasmon-induced hot carriers can be used to control both the growth and the etching behavior of gold nanoparticles (Au NPs) with laser irradiation. Here, the Au NPs placed on Si substrate are ...irradiated with a continuous wave laser (641 nm) in the presence of HAuCl4 solution. Irradiation results in growth/etching of Au NPs depending on the power, time, and HAuCl4 concentration. We reveal that the electronic band structure of the substrate plays a critical role in the growth/etching as it determines the charge transfer process. The growth is realized through the reduction of AuCl4− to Au(0) via hot-electron injection, while the holes are transferred to the substrate to avoid oxidative etching. If the holes are blocked due to the higher energy barriers or charge accumulation, only oxidative etching is observed. We further distinguish the hot-carrier-induced growth from that induced by plasmon-enhanced two-photon chemistry, where the latter is dominant in the Au nanorods/aggregates with large nonlinearity. Our results not only present a clear and in-depth understanding of the hot-carrier chemistry on the nanoparticles’ morphology but also provide a simple, in situ, and precise way to tune the size, shape, and compositions on a single-particle level, which is ready for on-chip fabrication and integration.
PDF
