Search

Staphylococcus aureus (S. aureus) residing in host macrophages is hard to clear because intracellular S. aureus has evolved mechanisms to hijack and subvert the immune response to favor intracellular infection. To overcome this challenge, nitrogen-phosphorous co-doped carbonized chitosan nanoparticles (NPCNs), which possess the polymer/carbon hybrid structures, were fabricated to clear intracellular S. aureus infection through chemotherapy and immunotherapy. Multi-heteroatom NPCNs were fabricated through the hydrothermal method, where chitosan and imidazole were used as the C and N sources and phosphoric acid as the P source. NPCNs can not only be used as a fluorescent probe for bacteria imaging but also kill extracellular and intracellular bacteria with low cytotoxicity. NPCNs could generate ROS and polarize macrophages into classically activated (M1) phenotypes to increase antibacterial immunity. Furthermore, NPCNs could accelerate intracellular S. aureus -infected wound healing in vivo. We envision that these carbonized chitosan nanoparticles may provide a new platform for clearing intracellular bacterial infection through chemotherapy and ROS-mediated immunotherapy. [Display omitted] [ABSTRACT FROM AUTHOR]

• It is the first time to report a PQS microchip Ho:SSO laser. • CW laser output maximum power:418 mW, slope efficiency:59.4%, absorbed pump power:2.5 W. • PQS laser output maximum power:332 Mw, slope efficiency:57.1%. • Maximum repetition frequency:0.69 kHz., maximum pulse energy:481 μJ, pulse width:103 ns. Represented here is a continuous-wave (CW) operation laser and a passively Q-switch (PQS) Ho:SSO microchip laser with a Cr2+:ZnSe saturable absorber (SA). An end-pumped Tm:YAP laser pumping was employed, which operated at room temperature. Up to our knowledge, it is the first time to report a PQS microchip Ho:SSO laser. A maximum 418 mW CW laser output was realized with an absorbed pump power of 2.5 W. The slope efficiency was 59.4%. In the PQS mode, the maximum output power was 332 mW, at the same time the slope efficiency was down to 57.1%. The maximum repetition frequency was 0.69 kHz. The maximum pulse energy of 481 μJ was realized corresponding to the pulse width of 103 ns. The pulsed characteristics were studied in this work. The output wavelength for different modes were also investigated. [ABSTRACT FROM AUTHOR]

Astrocytes activate and crosstalk with neurons influencing inflammatory responses following ischemic stroke. The distribution, abundance, and activity of microRNAs in astrocytes-derived exosomes after ischemic stroke remains largely unknown. In this study, exosomes were extracted from primary cultured mouse astrocytes via ultracentrifugation, and exposed to oxygen glucose deprivation/re‑oxygenation injury to mimic experimental ischemic stroke. SmallRNAs from astrocyte-derived exosomes were sequenced, and differentially expressed microRNAs were randomly selected and verified by stem-loop real time quantitative polymerase chain reaction. We found that 176 microRNAs, including 148 known and 28 novel microRNAs, were differentially expressed in astrocyte-derived exosomes following oxygen glucose deprivation/re‑oxygenation injury. In gene ontology enrichment, Kyoto encyclopedia of genes and genomes pathway analyses, and microRNA target gene prediction analyses, these alteration in microRNAs were associated to a broad spectrum of physiological functions including signaling transduction, neuroprotection and stress responses. Our findings warrant further investigating of these differentially expressed microRNAs in human diseases particularly ischemic stroke. • MicroRNAs in astrocytes derived exosomes play important roles in the regulation of cerebral ischemia. • Distinct changes of 176 microRNAs expression levels were found in astrocytes derived exosomes under OGD/R injury. • The target genes of identifided microRNAs engage in a variety of cellular processes. [ABSTRACT FROM AUTHOR]

In the present study, biochemical compositions changes and the related digestive enzymes activities were analyzed during development of eggs and yolk-sac larvae of turbot Scophthalmus maximus . Results showed that activities of pepsin and chymotrypsin increased on the whole, although small decreases occurred at gastrula stage. Trypsin activity presented the minimal value of 25.72 U/mg protein at blastula stage followed by obvious increase thereafter. Amylase activity was not detected until gastrula stage and increased later. As for lipase, it kept fluctuant tendency. The changes of digestive enzymes activities revealed the biochemical compositions dynamics. Both essential amino acids (EAA) and non-essential amino acids (NEAA) increased to the peak at blastula stage and decreased thereafter. Furthermore, the main components were leucine, lysine, valine, arginine and phenylalanine in EAA, and glutamic acid, aspartic acid, alanine and proline in NEAA. Free essential amino acids (FEAA) and non-essential amino acids (FNEAA) contents presented similar patterns of “decrease-increase-decrease-increase-decrease” as development went on, showing the maximal value of 271.00, 133.00 μg/g weight respectively at hatching day. Meanwhile, the main components were leucine, valine, threonine and lysine within FEAA, and alanine, tyrosine and serine within FNEAA. Regarding fatty acids contents, the quantitatively predominant fatty acids were C16:0 in saturates fatty acids (SFA), C18:1n-9 in monounsaturates fatty acids (MUFA), and C18:2n-6, C20:4n-6 (ARA) as well as C22:6n-3 (DHA) in polyunsaturates fatty acids (PUFA). Considering the utilization, there existed the preferential consumption of the unsaturated fatty acids (UFA) from cleavage to blastula stages, from segmentation stage to hatching and from 1 days after hatching (DAH) to 2 DAH, and SFA in other periods. Within the UFA, PUFA were consumed at a higher rate than MUFA from cleavage stage to blastula stage as well as yolk-sac periods, while MUFA were used at a more rapid rate during the other days. As for the individual fatty acids, there was a preferential consumption of C16:0, C16:1n-7 and C20:5n-3 during ontogeny. Overall, the changeable biochemical compositions revealed that the predominant energy fuel is carbohydrates before cleavage stage, amino acids until gastrula stage and fatty acids until 2 DAH. The above results are very valuable for clarifying nutritional requirements of turbot embryos and larvae, and deeply understanding the developmental mechanism. [ABSTRACT FROM AUTHOR]

Pesticide residue contamination has become an urgent issue since it threatens both the natural environment and public health. In this study, a fluorescent method for detecting dithiocarbamate (DTC) compounds was constructed based on novel nickel nanoclusters (Ni NCs) and copper ions (Cu2+). The water-soluble fluorescent Ni NCs were synthesized for the first time through a one-pot method using glutathione as stabilizer and ascorbic acid as reducing agent. The as-prepared Ni NCs exhibited a maximum fluorescence emission at 445 nm when excited by 380 nm. And they displayed aggregation-induced emission enhancement when ethylene glycol was introduced into the nanocluster aqueous solution. Based on the Ni NCs, a label-free fluorescence quenching sensor was established for sensitive and selective detection of DTC compounds with the assistance of Cu2+. The complex formed by DTC and Cu2+ led to fluorescence quenching of Ni NCs through inner filter effect. The sensing method was successfully applied to two typical DTC compounds, thiram and disulfiram, with good linearity over a wide linear range and a low detection limit. Moreover, the proposed approach was capable of thiram detection in real samples, which confirms the potential of this sensing method as a platform for DTC compound detection. [Display omitted] • Fluorescent GSH-Ni NCs with AIEE behavior were for the first time synthesized. • A fluorescent sensor for DTC compounds was developed based on the Ni NCs with the aid of Cu2+. • The first fluorescent sensing method for disulfiram was constructed. • The sensing mechanism was proved to be IFE between Ni NCs and Cu2+-DTC complex. [ABSTRACT FROM AUTHOR]

[Display omitted] • The latest progress in core–shell nanostructures for rapid SERS detection of pesticide residues is present. • The strengths and shortages of emerging core–shell SERS substrates are evaluated. • Future perspectives of novel SERS method together with core–shell nanostructures are discussed. Pesticide residues as an enormous menace to human health and environment have gained increasing attention in recent years. Powerful analytical methods are of great significance to monitor the levels of pesticide residues. Whereby, surface-enhanced Raman scattering (SERS) with its outstanding performance in ultra-sensitivity, non-destructive and the capability for molecular fingerprint has been employed in the relevant research. In more recent studies, core–shell nanostructures with multiple components have been applied as novel SERS substrates to accelerate the advancement of pesticide detection. Here, we provide a comprehensive review about the latest progress in the development of core–shell nanostructures for rapid SERS detection of pesticide residues. Various core–shell nanostructures are classified into metal and non-metal shell types including Au@Ag, Fe 3 O 4 @noble metal, SiO 2 @noble metal, noble metal@SiO 2 and others. Beyond reviewing different enhancement mechanisms of SERS, we also evaluate their strengths and shortages. Moreover, the feasibility of early-warning analysis of frequently used pesticides including carbamate, organophosphate, nitrogen heterocycle, pyrethroid and others are highlighted. It is expected that this review article will provides a clear reference for the future development of core–shell SERS substrates, and especially for applying them in various fields such as food safety, environmental monitoring, and agriculture protection. [ABSTRACT FROM AUTHOR]

This paper describes numerical simulations of the series and parallel water entry of supersonic projectiles with different head shapes, entry velocities, interval times, and interval distances. We focus on the cavity geometry and the drag force characteristics of the projectiles. For projectiles entering the water in series, no cavity is formed by the second projectile. This second projectile impacts and penetrates the water jet, and moves inside the cavity formed by the first projectile. Moreover, the impact drag force coefficient of the second projectile is significantly smaller than that of a single projectile entering the water with the same entry conditions. The cavitation drag force coefficient of the second projectile fluctuates. In the case of projectiles entering the water in parallel, the impact drag force coefficient is slightly smaller than that of single-projectile water entry. After the projectiles impact the water, the drag force coefficient declines sharply, increases again to form a small peak, and then reduces to an approximately constant value that is slightly larger than that of a single projectile entering the water. Additionally, although the outside boundary of the parallel water entry cavity shows a similar shape to that of single-projectile water entry, the blockage effect causes the inside boundary to form an approximately straight line. • Numerical simulations of supersonic projectiles series/parallel water entry under different conditions are conducted. • For projectiles entering the water in series, the cavitation drag force coefficient of the second projectile fluctuates. • The cavitation drag force coefficient of parallel water entry is slightly larger than that of a single projectile water entry. • The blockage effect causes the inside boundary of the cavity to form an approximate straight line. [ABSTRACT FROM AUTHOR]

In this study, a semi-analytical model was developed to study wave diffraction around a concentric three-cylinder system near a wall based on linear potential theory. As a critical element, the target problem is transformed into bidirectional incident wave diffraction around two concentric structures based on the image principle and an analytical solution is obtained through eigenfunction expansion combined with a matching technique and Graf's addition theorem. The validity of the proposed model was verified by comparing its results to known values. Parametric studies on porosity, annular spacing, incident angle, space between the structure and wall, and water depth were performed. The hydrodynamic loads and free-surface elevations in the system were calculated and compared to those reported in existing works on impermeable and permeable cylinders near a wall. The results indicate that the wave loads and run-ups on the exterior cylinder increase significantly based on the existence of the wall. However, based on the presence of an exterior porous protective structure, a significantly reduced influence of the wall on the interior cylinder can be observed. Considering the widespread use of concentric circular structures in ocean engineering, it is essential to conduct study on the hydrodynamic performance of concentric systems near walls, which can provide useful information for the design of marine structures. [ABSTRACT FROM AUTHOR]

Summary: Nuclear envelope proteins play important roles in chromatin organization, gene regulation, and signal transduction; however, the physiological role of these proteins remains elusive. We found that otefin (ote), which encodes a nuclear lamin, is essential for germline stem cell (GSC) maintenance. We show that Ote, as an intrinsic factor, is both necessary and sufficient to regulate GSC fate. Furthermore, we demonstrate that ote is required for the Dpp/BMP signaling pathway to silence bam transcription. By structure-function analysis, we demonstrate that the nuclear membrane localization of Ote is essential for its role in GSC maintenance. Finally, we show that Ote physically interacts with Medea/Smad4 at the bam silencer element to regulate GSC fate. Thus, we demonstrate that specific nuclear membrane components mediate signal-dependent transcriptional effects to control stem cell behavior. [Copyright &y& Elsevier]

The interaction between cnoidal waves and a concentric cylindrical structure with an arc-shaped outer wall has been investigated theoretically using eigenfunction expansion approach. The arc-shaped outer cylinder is permeable and thin, protecting the porous dual-cylinder structure. Three cylinders are surface-piercing and rigidly installed on the flat bottom of an ocean. Analytical solutions were obtained based on the first approximation to cnoidal waves. A series of linear equations pertaining to unknown coefficients were solved using matching boundary conditions. Hydrodynamic forces on the cylinders and the diffracted wave faces around the cylinders were evaluated, and the effects of water depth, annular spacing, angle of incidence and structure configuration including the porosity parameter of the cylinders and the opening angle are illustrated via numerical results. The numerical results obtained for limiting cases agreed well with published results for a solid cylinder. The results indicated that the wave forces on the inner structure did not change significantly when the opening angle was greater than 2 π ∕ 3. The hydrodynamic loads on the inner cylinder of the concentric cylindrical structure were significantly lower than the wave force on a single cylinder. Moreover, the value of wave force on the inner cylinder of a concentric dual-cylinder structure with an arc-shaped outer wall was similar to that on the inner cylinder of a concentric two-cylinder system. • Cnoidal wave interaction with a concentric system is investigated. • The arc-shaped cylinder works well to protect the interior structure. • The wave forces become stable as the opening angle exceeds a fixed angle. [ABSTRACT FROM AUTHOR]

[Display omitted] • A facile, sustainable self-sacrifice template strategy has been disclosed for the synthesis of porous Co@CN. • This strategy is easily scalable, and can be generally applicable to prepare other transition-metal@CN catalysts. • There is the first example on the synthesis of porous Co@CN derived from biomass for the oxidative esterification of HMF. • Zn plays dual roles as the sacrificial template and acid-base site regulator in the synthetic and catalytic processes. A newly developed, facile and sustainable self-sacrifice template strategy, in which zinc and chitosan were used as the sacrificial template and carbon source respectively, has been disclosed for the synthesis of a hollow Co-embedded in nitrogen-doped graphite (Co@CN) structure. This material exhibits excellent catalytic efficiency in the oxidative esterification of 5-hydroxymethylfurfural to 2,5-furandicarboxylicacid dimethyl ester that is a significant raw material for polymer synthesis. According to the experimental and calculation results, zinc as the self-sacrificial template and acid-base site regulator has significantly improved the performance of the catalyst. The high specific surface area owing to the partial evaporation of zinc and the optimization of basic and acid sites in the catalyst prove to be the main reasons for its high activity. [ABSTRACT FROM AUTHOR]

Hierarchical flower-like WO 3 with exposed active {-112} facets synthesized using a microwave-assisted gas-liquid interfacial solvothermal method shows a superior triethylamine gas sensing performance at room temperature. • The flower-like WO 3 with exposed active {-112} facets can be controllably synthesized using a microwave-assisted method. • {-112} faceted WO 3 shows the best gas sensing response to trimethylamine at room temperature with excellent selectivity. • Our results evidence the strategy to improve the gas sensing performance of metal oxides through surface engineering. • The as-prepared gas sensor qualifies the great potential for trimethylamine practical detection and monitoring. Effective detection of triethylamine (TEA) is important for the human health and environment, while challenging. In this study, a novel hierarchical flower-like WO 3 nanomaterial was synthesized using a microwave-assisted gas-liquid interface method. The morphology and exposed facets of WO 3 nanomaterials can be manipulated through the control of the volume ratio between the water and ethylene glycol (EG) during the synthesis. Our results demonstrate that the samples prepared with water/EG ratio of 8:32 are mainly exposed {-112} facets, which have the best gas sensing response of 180.7 to 100 ppm TEA at room temperature (RT). Its superior gas sensing performance and stability are also evidenced by the short recovery speed of 72 s to 100 ppm TEA at RT. More importantly, our experiments revealed an excellent selectivity in terms to other volatile organic compounds and further confirmed by the first-principles theoretical results. The outcomes of this study suggest that the surface engineering technique is a promising approach to improve the gas sensing performance of metal oxides gas sensor and show great potential for TEA practical detection and monitoring. [ABSTRACT FROM AUTHOR]

• Phosphatidic acid (PA) can bind to MKK7 and MKK9. • MKK7 and MKK9 positively regulate plant salt tolerance with functional redundancy. • PA signal increases MKK7/MKK9-catalyzed phosphorylation of MPK6 under salt stress. • PA induces the translocation of MKK7 and MKK9 to plasma membrane under salt stress. Phosphatidic acid (PA) is a lipid secondary messenger involved in intracellular signaling in eukaryotes. It has been confirmed that PA mediates salt stress signaling by promoting activation of Mitogen-activated Protein Kinase 6 (MPK6) which phosphorylates Na+/H+ antiporter SOS1. However, the MPK6-upstream kinases and their relationship to PA remain unclear. Here, we found that, among the six tested Arabidopsis Mitogen-activated Protein Kinase Kinases (MKKs), PA specifically bound to MKK7 and MKK9 which phosphorylate MPK6, and promoted the activation of MKK7/MKK9. Based on phenotypic and physiological analyses, we found that MKK7 and MKK9 positively regulate Arabidopsis salt tolerance and are functionally redundant. NaCl treatment can induce significant increase in MKK7/MKK9 activities, and this depends, in part, on the Phospholipase Dα1 (PLDα1). MKK7 and MKK9 also mediate the NaCl-induced activation of MPK6. Furthermore, PA or NaCl treatment could induce translocation of MKK7/MKK9 to the plasma membrane, whereas this translocation disappeared in pldα1. These results indicate that PA binds to MKK7 and MKK9, increases their kinase activity and plasma membrane localization during Arabidopsis response to salt stress. Together with the PA-MPK6-SOS1 pathway identified previously, this mechanism may maximize the signal transduction efficiency, providing novel insights into the link between lipid signaling and MAPK cascade. [ABSTRACT FROM AUTHOR]