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Klebsiella pneumoniae is an important multidrug-resistant (MDR) pathogen that can cause a range of infections in hospitalized patients. With the growing use of antibiotics, MDR K. pneumoniae is more prevalent, posing additional difficulties and obstacles in clinical therapy. To provide a valuable reference to deeply understand K. pneumoniae, and also to provide the theoretical basis for clinical prevention of such bacteria infections, the antibiotic resistance and mechanism of K. pneumoniae are discussed in this article. We conducted a literature review on antibiotic resistance of K. pneumoniae. We ran a thorough literature search of PubMed, Web of Science, and Scopus, among other databases. We also thoroughly searched the literature listed in the papers. We searched all antibiotic resistance mechanisms and genes of seven important antibiotics used to treat K. pneumoniae infections. Antibiotics such as β-lactams, aminoglycosides, and quinolones are used in the treatment of K. pneumoniae infection. With both chromosomal and plasmid-encoded ARGs, this pathogen has diverse resistance genes. Carbapenem resistance genes, enlarged-spectrum β-lactamase genes, and AmpC genes are the most often β-lactamase resistance genes. K. pneumoniae is a major contributor to antibiotic resistance worldwide. Understanding K. pneumoniae antibiotic resistance mechanisms and molecular characteristics will be important for the design of targeted prevention and novel control strategies against this pathogen.

Palygorskite is a fibrous magnesium-rich clay mineral with a typical tunnel structure, and its adsorption properties make it an ideal adsorbent for broad applications. Thus, revealing the confinement effects on tunnel species can help in understanding its adsorption properties. Grand canonical Monte Carlo and molecular dynamics simulations were performed to analyze the effects of the crystal chemistry of palygorskite on the adsorption, occurrence, and mobility of tunnel water. Water adsorption isotherm, distribution models, and mobility were achieved from these simulations. Zeolitic water emerges into the tunnels even at a low relative humidity (RH) (such as 5%) and completely fills the tunnels as the RH increases to 10%. In neutral palygorskite, the influence of the octahedral type on water adsorption is not obvious, but the influence of tunnel cations is obvious. The occupation of Na+ ions in tunnels can reduce the maximum water amount and affect the spatial distribution of zeolitic water. The water distribution in tunnels can be described by a two-zeolitic water-site model for neutral palygorskite and a one-zeolitic water-site model for the charged one. The zeolitic water confined in the tunnel presents very low mobility, and the appearance of Na+ ions in the charged palygorskite further reduces the mobility of zeolitic water. Compared with other clay minerals, the much lower water mobility of palygorskite implies that it may have a more efficient fixation on foreign molecules or ions in environmental applications. [ABSTRACT FROM AUTHOR]

Senescence of activated hepatic stellate cells (aHSCs) is a stable growth arrest that is implicated in liver fibrosis regression. Senescent cells often accompanied by a multi‐faceted senescence‐associated secretory phenotype (SASP). Induction of aHSCs senescence by inhibiting SASP may be a potential therapeutic model against hepatic fibrosis. To evaluate the role of atractylenolide III (ATR III) in the development of chemotherapeutic drug‐induced SASPs in hepatic stellate cells. Etoposide‐induced senescent HSC‐LX2 model was established and treated with ATR III at different concentrations (20, 30 and 40 μM). We found that ATR III dose‐dependently enhanced senescence in etoposide‐induced LX2 cells. ATR III dose‐dependently decreased the release and expression of SASP factors (interleukin [IL]‐1α, IL‐1β, IL6 and IL‐8) in senescent cells. ATR III regulated cyclic GMP‐AMP synthase (cGAS)/nuclear factor κ (NF‐κB) signalling to affect SASP expression in senescent cells. The addition of 2'3′ cGAMP counteracted the effect of ATR III. The release of SASP factors in the conditioned medium from senescent cells could affect cell migration, proliferation and contraction through paracrine manner. Our results indicated ATR III could still enter senescence and prevent the production of SASP and its paracrine effects in senescent cells, an effect that may be related to the possible inhibition of cGAS/NF‐κB signalling by ATR III. Our study proves that ATR III may be an effective potential drug against liver fibrosis by promoting aHSC senescence, which can provide a new choice for the future clinical treatment of liver fibrosis. [ABSTRACT FROM AUTHOR]

CO2-Switchable surfactants are of great potential in a wide range of industrial applications related to their ability to stabilize and destabilize emulsions upon command. Molecular dynamics simulations have been performed to reveal the fundamental mechanism of the reversible emulsification/demulsification processes of a dodecane–saline system by a CO2-switchable surfactant that switches between active (i.e., N′-dodecyl-N,N-dimethylacetamidinium (DMAAH+)) and inactive (i.e., N′-dodecyl-N,N-dimethylacetamidine (DMAA)) forms. The density profiles indicate that DMAAH+ could increase the oil–water interfacial thickness to a greater extent compared to DMAA. DMAAH+ could sharply reduce the interfacial tension of the dodecane–saline system, while DMAA only exhibits a limited decrease, which is in accordance with the experimental observation that DMAAH+/DMAA can reversibly emulsify/demulsify alkane–water systems. Our simulations showed that both the number and lifetime of hydrogen bonds (HBs) between DMAA and water are almost equal to those between DMAAH+ and water. In DMAA, the N atom connecting with the alkyl tail acted as a HB acceptor, while the N atom attached by a proton in DMAAH+ acted as a HB donor. Furthermore, the HBs between DMAAH+ and HCO3− at the interfaces are relatively limited. Hence, it is deduced that the HBs are insufficient to achieve the CO2-switchability of DMAA/DMAAH+. The Lennard Jones and coulombic potentials between DMAA/DMAAH+ and other species show that the coulombic potentials between DMAAH+ and water or anions (i.e., Cl− and HCO3−) sharply decrease with the increase of DMAAH+ and are much lower than those in models with DMAA. The enhanced coulombic interactions between DMAAH+ and anions lead to a remarkable reduction in interfacial tension and the emulsification of the alkane–saline system. Therefore, coulombic interactions are of crucial importance to the reversible emulsification/demulsification processes regulated by CO2-switchable surfactants, namely DMAAH+/DMAA. [ABSTRACT FROM AUTHOR]

AbstractThis study compares three transfer learning strategies for adapting convolutional neural network (CNN) models in near-infrared spectroscopy to new instruments. Strategy 1 freezes pre-trained weights except for the output layer; Strategy 2 fine-tunes all weights with new data; Strategy 3 adds new fully connected layers to the pre-trained model. Using tablet spectra to predict active pharmaceutical ingredient content, results show that fine-tuning all network weights (Strategy 2) yields the best performance. The study also finds that moderate training sample sizes balance model accuracy and resource expenditure. Transfer learning is effective for near-infrared model transfer. [ABSTRACT FROM AUTHOR]

CO2-Switchable surfactants are of great potential in a wide range of industrial applications related to their ability to stabilize and destabilize emulsions upon command. Molecular dynamics simulations have been performed to reveal the fundamental mechanism of the reversible emulsification/demulsification processes of a dodecane-saline system by a CO2-switchable surfactant that switches between active (i.e., N'-dodecyl-N,N-dimethylacetamidinium (DMAAH+)) and inactive (i.e., N'-dodecyl-N,N-dimethylacetamidine (DMAA)) forms. The density profiles indicate that DMAAH+ could increase the oil-water interfacial thickness to a greater extent compared to DMAA. DMAAH+ could sharply reduce the interfacial tension of the dodecane-saline system, while DMAA only exhibits a limited decrease, which is in accordance with the experimental observation that DMAAH+/DMAA can reversibly emulsify/demulsify alkane-water systems. Our simulations showed that both the number and lifetime of hydrogen bonds (HBs) between DMAA and water are almost equal to those between DMAAH+ and water. In DMAA, the N atom connecting with the alkyl tail acted as a HB acceptor, while the N atom attached by a proton in DMAAH+ acted as a HB donor. Furthermore, the HBs between DMAAH+ and HCO3- at the interfaces are relatively limited. Hence, it is deduced that the HBs are insufficient to achieve the CO2-switchability of DMAA/DMAAH+. The Lennard Jones and coulombic potentials between DMAA/DMAAH+ and other species show that the coulombic potentials between DMAAH+ and water or anions (i.e., Cl- and HCO3-) sharply decrease with the increase of DMAAH+ and are much lower than those in models with DMAA. The enhanced coulombic interactions between DMAAH+ and anions lead to a remarkable reduction in interfacial tension and the emulsification of the alkane-saline system. Therefore, coulombic interactions are of crucial importance to the reversible emulsification/demulsification processes regulated by CO2-switchable surfactants, namely DMAAH+/DMAA.

Objective: A novel bHLH-like gene, designated SmbHLH1, was isolated from Salvia miltiorrhiza, in order to identify a bHLH gene in related to danshinone biosysnthesis., Method: SmbHLH1 was isolated by RT-PCR,and Semi-quantitative RT-PCR was used to detect the gene expression level., Result: The full length of SmbHLH1 cDNA has an open reading frame of 999 bp. The deduced amino acid sequence of SmbHLH1 has 332 amino acid residues which forms a 36 kDa polypeptide with a calculated pI of 5.4. SmbHLH1 gene was expressed at high level in root, but low level in stem, leaf and flower of S. miltiorrhiza. The transcripts of SmbHLH1 was suppressed when the plants were treated with exogenous MeJA, Yeast + Ag+. The transcripts of SmbHLH1 constitutively accumulated in response to exogenous ABA and low concentration of salicylic acid., Conclusion: SmbHLH is a new member of the S. miltiorrhiza bHLH family, and its possible roles in brassinosteriods signaling responses.