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"Long, Yan"
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Surface ligand controls silver ion release of nanosilver and its antibacterial activity against Escherichia coli
Understanding the mechanism of nanosilver-dependent antibacterial activity against microorganisms helps optimize the design and usage of the related nanomaterials. In this study, we prepared four kinds of 10 nm-sized silver nanoparticles (AgNPs) with dictated surface chemistry by capping different ligands, including citrate, mercaptopropionic acid, mercaptohexanoic acid, and mercaptopropionic sulfonic acid. Their surface-dependent chemistry and antibacterial activities were investigated. Owing to the weak bond to surface Ag, short carbon chain, and low silver ion attraction, citrate-coated AgNPs caused the highest silver ion release and the strongest antibacterial activity against
, when compared to the other tested AgNPs. The study on the underlying antibacterial mechanisms indicated that cellular membrane uptake of Ag, NAD
/NADH ratio increase, and intracellular reactive oxygen species (ROS) generation were significantly induced in both AgNP and silver ion exposure groups. The released silver ions from AgNPs inside cells through a Trojan-horse-type mechanism were suggested to interact with respiratory chain proteins on the membrane, interrupt intracellular O
reduction, and induce ROS production. The further oxidative damages of lipid peroxidation and membrane breakdown caused the lethal effect on
. Altogether, this study demonstrated that AgNPs exerted antibacterial activity through the release of silver ions and the subsequent induction of intracellular ROS generation by interacting with the cell membrane. The findings are helpful in guiding the controllable synthesis through the regulation of surface coating for medical care purpose.
Journal Article
Enabling C2H2/CO2 Separation Under Humid Conditions with a Methylated Copper MOF
As a unique subclass of metal‐organic frameworks (MOFs), MOFs with open metal site (OMS) are demonstrated efficient gas separation performance through pi complexation with unsaturated hydrocarbons. However, their practical application faces the challenge of humidity that causes structure degradation and completive binding at the OMS. In this work, the effect of linker methylation of a copper MOF (BUT‐155) on the C2H2/CO2 separation performance under humid condition is evaluated. The water adsorption isotherm, adsorption kinetics, and breakthrough under dry and humid conditions are performed. The BUT‐155 with methylated linker exhibits lower water uptake and adsorption kinetics under humid condition (RH = 20%), in comparison with HKUST‐1. Therefore, the C2H2/CO2 separation performance of BUT‐155 is much less affected by water, especially under higher gas flow rate. Moreover, the dynamic C2H2/CO2 separation performance of BUT‐155 can maintain five breakthrough cycles under humid conditions (RH = 20% and RH = 80%) without obvious performance degradation. The presence of abundant methyl groups in a Cu‐MOF leads to significantly reduced water uptake and slower water adsorption kinetics, thereby protecting the framework from hydrolysis, as well as inhibiting the water binding at open metal sites. Subsequently, C2H2/CO2 separation under different humid levels is realized with high recyclability.
Journal Article
NIR II-responsive photon upconversion through energy migration in an ytterbium sublattice
Smart control of photon upconversion is a key strategy for lanthanide-based materials used in biological and photonic applications. However, this has remained a challenge for the upconversion luminescence of lanthanides under excitation in the second near-infrared (NIR II) biowindow instead of at the conventional 980 and 808 nm wavelengths. Here, we report a conceptual design for an energy-migratory ytterbium sublattice in an erbium-sensitized multilayer core–shell nanostructure that is able to achieve photon upconversion from a broad range of lanthanide ions (Yb3+, Tm3+, Ho3+, Gd3+, Eu3+ and Tb3+) under 1,530 nm irradiation. The quasi-single-band upconversion in the first near-infrared (NIR I) biowindow is also realized through fine manipulation of the introduced cross-relaxations. By establishing an interfacial energy-transfer-mediated nanostructure, we also gain a deep insight into the mechanistic features of the energy migration. These results open new opportunities in a variety of frontier applications, such as information security.An ytterbium sublattice in an erbium-sensitized multilayer core–shell structure enables photon upconversion from lanthanide ions under 1,530 nm irradiation.
Journal Article
Spatiotemporal control of photochromic upconversion through interfacial energy transfer
Dynamic control of multi-photon upconversion with rich and tunable emission colors is stimulating extensive interest in both fundamental research and frontier applications of lanthanide based materials. However, manipulating photochromic upconversion towards color-switchable emissions of a single lanthanide emitter is still challenging. Here, we report a conceptual model to realize the spatiotemporal control of upconversion dynamics and photochromic evolution of Er
3+
through interfacial energy transfer (IET) in a core-shell nanostructure. The design of Yb sublattice sensitization interlayer, instead of regular Yb
3+
doping, is able to raise the absorption capability of excitation energy and enhance the upconversion. We find that a nanoscale spatial manipulation of interfacial interactions between Er and Yb sublattices can further contribute to upconversion. Moreover, the red/green color-switchable upconversion of Er
3+
is achieved through using the temporal modulation ways of non-steady-state excitation and time-gating technique. Our results allow for versatile designs and dynamic management of emission colors from luminescent materials and provide more chances for their frontier photonic applications such as optical anti-counterfeiting and speed monitoring.
Achieving spatiotemporal control of photochromic upconversion from a single lanthanide emitter remains challenging. Here, the authors present a conceptual model enabling such control of Er
3+
photochromic upconversion via interfacial energy transfer in a core-shell nanostructure.
Journal Article
Genomic insights into Yanbian cattle: Breed-specific selective sweeps identified by whole-genome sequencing
The Chinese Yanbian Yellow cattle are an indigenous East Asian breed, closely related to the Korean Hanwoo cattle, and presumably share the same origin. However, unlike Hanwoo, which has undergone approximately 40 years of intensive artificial selection, Yanbian cattle have remained relatively unselected, preserving diverse genetic characteristics. In this study, we used whole-genome sequencing data from 45 individuals to investigate the unique traits in Yanbian cattle. To identify selective sweep regions and compare the results depending on different methods, we applied three approaches: cross-population extended haplotype homozygosity (XP-EHH), cross-population composite likelihood ratio (XP-CLR), and population branch statistics (PBS) based on the fixation index. Our results highlight the PEX14 gene and SIRT6 gene which play a role in cold adaptation, showing high XP-CLR value with clear evidence of fixation. Notably, the genomic region containing PEX14 , which is involved in the browning of white adipose tissue in response to cold exposure, exhibited reduced nucleotide diversity and low Tajima’s D value in Yanbian cattle. This suggests that natural selection has acted on this gene to facilitate cold adaptation. Furthermore, genomic regions with early fixation events were primarily associated with environmental adaptation, whereas more recent fixation events were related to economically important traits. These findings enhance our understanding of the genomic characteristics of Yanbian cattle and support their potential for environmental adaptation, providing valuable insights for future improvement efforts.
Journal Article
Experimental Study on Rock Strength and Deformation Characteristics Under Triaxial Cyclic Loading and Unloading Conditions
The mechanical behavior of rock under cyclic loading is quite complicated compared to monotonic loading or unloading conditions. The triaxial cyclic loading and unloading testing of rock specimens under 6 confining pressures (σ3) was carried out through the MTS 815 rock mechanics testing system, to explore the strength, deformation, and expansion characteristics of the rock specimens. The stress–strain curves of the rock specimens in the triaxial cyclic loading and unloading testing presented the hysteresis effect. Besides, as σ3 increased, the rock specimen strength increased, while the failure form brittle to ductile. The elasticity modulus (El) increased first and consequently decreased as the cycle index increased, while it increased as σ3 increased. However, the generalized Poisson’s ratio (μl) increased as the cycle index increased, whereas it decreased as the σ3 increased. Based on the Mohr–Coulomb strength criterion and plastic shear strain (γp) as the plastic parameter, the subsequent yield plane model of the loaded rock was characterized by generalized cohesion (c´) and generalized internal friction angle (φ´). Ultimately, the evolution rules of c´, φ´ and Ψ (dilatancy angle), with σ3 and γp were revealed. Moreover, the post-peak dilatancy angle models with regard to the influence of σ3 and γp on the volume dilatancy of the rock specimen were established, which indicated that Ψ increased first and consequently decreased along with the γp increase, whereas it decreased as the σ3 increased.
Journal Article
The nuclear factor kappa B signaling pathway is a master regulator of renal fibrosis
Renal fibrosis is increasingly recognized as a global public health problem. Acute kidney injury (AKI) and chronic kidney disease (CKD) both result in renal fibrosis. Oxidative stress and inflammation play central roles in progressive renal fibrosis. Oxidative stress and inflammation are closely linked and form a vicious cycle in which oxidative stress induces inflammation through various molecular mechanisms. Ample evidence has indicated that a hyperactive nuclear factor kappa B (NF-ƙB) signaling pathway plays a pivotal role in renal fibrosis. Hyperactive NF-ƙB causes the activation and recruitment of immune cells. Inflammation, in turn, triggers oxidative stress through the production of reactive oxygen species and nitrogen species by activating leukocytes and resident cells. These events mediate organ injury through apoptosis, necrosis, and fibrosis. Therefore, developing a strategy to target the NF-ƙB signaling pathway is important for the effective treatment of renal fibrosis. This Review summarizes the effect of the NF-ƙB signaling pathway on renal fibrosis in the context of AKI and CKD (immunoglobulin A nephropathy, membranous nephropathy, diabetic nephropathy, hypertensive nephropathy, and kidney transplantation). Therapies targeting the NF-ƙB signaling pathway, including natural products, are also discussed. In addition, NF-ƙB-dependent non-coding RNAs are involved in renal inflammation and fibrosis and are crucial targets in the development of effective treatments for kidney disease. This Review provides a clear pathophysiological rationale and specific concept-driven therapeutic strategy for the treatment of renal fibrosis by targeting the NF-ƙB signaling pathway.
Journal Article
PIK3CA mutations confer resistance to first-line chemotherapy in colorectal cancer
Chemotherapy represents an important treatment option for colorectal cancer (CRC), but only half of the patients benefit from these regimens. We explored the potential predicting value and mechanism of PIK3CA mutation in CRC chemotherapy. CRC specimens from 440 patients were retrospectively collected and examined with a fluorescence PCR-based method. The correlation of first-line chemotherapy response and PIK3CA mutation was evaluated according to follow-up and medical records. The underlying mechanism of PIK3CA mutation in chemotherapy resistance was assessed with CRC tumors and primary cells. The mutation frequency of the
PIK3CA
gene in CRC patients was 9.55%, which was correlated with late TNM staging and lower histological grade. The CRC patients with
PIK3A
mutation showed worse response to first-line chemotherapy than those without
PIK3CA
mutation. PIK3A mutation tumor cells showed poor sensitivity to first-line chemotherapy in vitro and in vivo. PIK3CA mutation induced PI3K/Akt signaling activation to increase LGR5
+
CRC stem cells survival and proliferation, from which lead to chemotherapy resistance. Furthermore,
PIK3CA
mutation
/LGR5
+
expression was an independent detrimental factor for CRC patients. Our findings indicated that PIK3CA mutation induced PI3K/Akt activation contributed to CRC stem cells survival and proliferation, from which cells further resistance to chemotherapy. PIK3CA
mutation
/LGR5
+
expression was a potential biomarker for monitoring chemotherapy resistance in CRC.
Journal Article
BICELLULAR POLLEN 1 is a modulator of DNA replication and pollen development in Arabidopsis
• During male gametogenesis in Arabidopsis, the haploid microspore undergoes an asymmetric division to produce a vegetative and a generative cell, the latter of which continues to divide symmetrically to form two sperms. This simple system couples cell cycle with cell fate specification.
• Here we addressed the role of DNA replication in male gametogenesis using a mutant bicellular pollen 1 (bice1), which produces bicellular, rather than tricellular, pollen grains as in the wild-type plant at anthesis.
• The mutation prolonged DNA synthesis of the generative cell, which resulted in c. 40% of pollen grains arrested at the two-nucleate stage. The extended S phase did not impact the cell fate of the generative cell as shown by cell-specific markers. BICE1 encodes a plant homolog of human D123 protein that is required for G1 progression, but the underlying mechanism is unknown.
• Here we showed that BICE1 interacts with MCM4 and MCM7 of the pre-replication complex. Consistently, double mutations in BICE1 and MCM4, or MCM7, also led to bicellular pollen and condensed chromosomes. These suggest that BICE1 plays a role in modulating DNA replication via interaction with MCM4 and MCM7.
Journal Article