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Background Magnetosomes (BMPs) are organelles of magnetotactic bacteria (MTB) that are responsible for mineralizing iron to form magnetite. In addition, BMP is an ideal biomaterial that is widely used in bio- and nano-technological applications, such as drug delivery, tumor detection and therapy, and immunodetection. The use of BMPs to create multifunctional nanocomposites would further expand the range of their applications. Results In this study, we firstly demonstrate that the extracted BMP can remineralize in vitro when it is exposed to AgNO3 solution, the silver ions (Ag+) were transported into the BMP biomembrane (MM) and mineralized into a silver crystal on one crystal plane of Fe3O4. Resulting in the rapid synthesis of an Ag-Fe3O4 hybrid BMP (BMP-Ag). The synergy between the biomembrane, Fe3O4 crystal, and unmineralized iron enabled the remineralization of BMPs at an Ag+ concentration ≥ 1.0 mg mL−1. The BMP-Ag displayed good biocompatibility and antibacterial activity. At a concentration of 2.0 mg/mL, the BMP-Ag and biomembrane removed Ag-Fe3O4 NPs inhibited the growth of gram-negative and gram-positive bacteria. Thus using BMP-Ag as a wound dressing can effectively enhance the contraction of infected wounds. Conclusions This study represents the first successful attempt to remineralize organelles ex vivo, realizing the biosynthesis of hybrid BMP and providing an important advancement in the synthesis technology of multifunctional biological nanocomposites. Graphical abstract

For hypereutectic Nb-Si based alloys, primary Nb5Si3 phases typically grow in a faceted mode during equilibrium or near-equilibrium solidification, which damages the ductility and toughness. To address this issue, here we artificially manipulate the growth morphology of Nb5Si3 using electron beam surface melting (EBSM) and subsequent annealing treatments. Results show that such a non-equilibrium solidification pathway enables the transition from faceted growth to non-faceted dendritic growth of Nb5Si3, along with evident microstructure refinement, generation of metastable β-Nb5Si3 phases and elimination of chemical segregation. The transformation from β-Nb5Si3 to α-Nb5Si3 and Nb solid solution (Nbss) particles is triggered by the annealing treatment at 1450 °C for 5 h. Also, we find the annealing-mediated formation of inherited Nb5Si3 dendrites that maintain the dendritic morphology of the original as-solidified β-Nb5Si3 dendrites. This work thus provides a feasible routine to obtain thermally stable and refined α-Nb5Si3 dendrites in hypereutectic Nb-Si based alloys.

Non-precious metal-based electrocatalyst with high activity and stability for efficient hydrogen evolution reaction (HER) is of critical importance toward low-cost and large-scale water splitting. Traditional MoS2 has electrocatalytic hydrogen evolution inertness in alkaline environment, which is detrimental to the adsorption and dissociation of water. Composited with electrocatalyst with good electrical conductivity can enhance its HER activity. In this work, we for the first time construct a carbon-supported hollow heterostructure MoS2@Mo2C composite via two-step calcination and sulfurized process from carbonized Mo2C–Mo3C2 heteronanowires. The results show that the existence of the Mo3C2 phase is the key point to construct the effective heterostructure with hollow morphology. Due to the strong negative hydrogen binding energy for H on surface of Mo2C, the H+ reduction in the MoS2@Mo2C in the Volmer step can be enhanced. Compared with MoS2, MoS2@Mo2C has high electrocatalytic activity for hydrogen evolution with an onset potential of 28 mV, overpotential of 129 mV at the current density of 10 mA cm−2, a small Tafel slope of 78 mV dec−1, and an excellent stability. This work will provide new insights into the design of high-efficiency HER catalysts via interfacial engineering at nanoscale for commercial water splitting.

This paper focuses on the production of a high-affinity monoclonal antibody (mAb) that can efficiently detect and block purinergic ligand-gated ion channel 7 receptor (P2X7R). To achieve this goal, the extracellular domain of human P2X7R, P2X7R-ECD, was used as an immunogen for BALB/c mice, inducing them to produce spleen lymphocytes that were subsequently fused with myeloma cells. Screening of the resultant hybridoma clones resulted in the selection of one stable positive clone that produced a qualified mAb, named 4B3A4. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis demonstrated that the purity of the purified 4B3A4 mAb was above 85%, with prominent bands corresponding to molecular weights of 55 kDa (heavy chain) and 25 kDa (light chain), and the BCA assay showed that the concentration of the purified 4B3A4 mAb was 0.3 mg/mL. Western blot analysis revealed that the 4B3A4 mAb could specifically recognize and bind both P2X7R-ECD and the full-length P2X7R protein. Laser scanning confocal microscopy (LSCM) revealed that the 4B3A4 mAb specifically bound to P2X7R on the membrane of human peripheral blood mononuclear cells (PBMCs). P2X7R expression was significantly different between healthy individuals and people with certain cancers as determined by flow cytometry (FCM). In addition, the 4B3A4 mAb significantly reduced ATP-stimulated Ca2+ entry and YO-PRO-1 uptake, which indicated that the 4B3A4 mAb effectively blocked P2X7R activity. These data indicate that the 4B3A4 mAb can be further used as not only an antibody to detect cell surface P2X7R but also as a therapeutic antibody to target P2X7R-related signaling pathways.

In obesity, macrophages drive a low-grade systemic inflammation (LSI) and insulin resistance (IR). The ribosome biosynthesis protein NOC4 (NOC4) mediates 40 S ribosomal subunits synthesis in yeast. Hereby, we reported an unexpected location and function of NOC4L, which was preferentially expressed in human and mouse macrophages. NOC4L was decreased in both obese human and mice. The macrophage-specific deletion of Noc4l in mice displayed IR and LSI. Conversely, Noc4l overexpression by lentivirus treatment and transgenic mouse model improved glucose metabolism in mice. Importantly, we found that Noc4l can interact with TLR4 to inhibit its endocytosis and block the TRIF pathway, thereafter ameliorated LSI and IR in mice., Macrophage inflammation promotes insulin resistance during diet-induced obesity. Here the authors show that macrophage NOC4L is decreased in humans and mice with obesity, that macrophage NOC4L deficiency aggravated high-fat diet induced inflammation and insulin resistance, and that NOC4L interacts with toll-like receptor 4, to inhibit endocytosis, and thus blocks TLF4/TRIF inflammatory signaling.

Radiolabeled epidermal growth factor receptor (EGFR) targeted antibody could be used for imaging EGFR expressing cancer. In this study, the SPECT probe 125I-Necitumumab were synthesized and evaluated for SPECT imaging of non-small cell lung cancer (NSCLC). In vivo biodistribution study indicated that 125I-Necitumumab was cleared rapidly in most organs and tissues. Though the tumor expressed a relatively high level of EGFR, however SPECT images showed no obvious uptake in the tumors. Therefore, we considered that 125I-Necitumumab was not suitable for EGFR-targeted NSCLC SPECT imaging.

The cast Al-Si alloy was fabricated using the Additive Pressure Casting (APC) method. The effects of holding pressure from 50 to 400 kPa on the density, cooling rate, and mechanical properties of the alloy, and the corresponding mechanism were discussed. The results indicate that the application of high holding pressure (300 kPa) enhances the feeding ability of the alloy, leading to an increase of the density. Meanwhile, the cooling rate of the alloy is increased by 100%. In addition, the tensile testing results show that the increase of holding pressure from 50 to 300 kPa improves the tensile strength and elongation of the alloy by 6.2% and 81.3%, respectively. However, excessive holding pressure (400 kPa) might lower the density and cooling rate of the alloy due to the feeding channels being blocked.

Many studies have examined transfer of working memory (WM) training improvements to non-trained cognitive tasks, with largely disappointing results. Interference control has been suggested to be a central feature of WM. However, studies examining transfer effects of a training program exclusively and directly targeting interference control are lacking. Forty-one 10‒12 year-old children and 47 19‒24 year-old adults were assigned to an adaptive interference control training or active control condition. Transfer of training effects to tasks measuring interference control, response inhibition, WM updating, task-switching, and non-verbal fluid intelligence were assessed during a 3-month follow-up session and/or an immediate post-training session. Substantial evidence of training improvements and a positive transfer effect to a non-trained interference control task were observed for both age groups. Marginal evidence for beneficial transfer of training effects for the trained compared to non-trained participants was found for a WM task for both age groups, and for the children for another interference control task and a response inhibition task. However, these transfer effects were absent during the 3-month follow-up measurement. These results suggest some potential for interference control training programs to enhance aspects of cognitive functioning, with some evidence for a more wide-spread, but short-lived, transfer for children compared to adults.

Microstructures and oxidation behaviors of four Dy-doped Nb–Si-based alloys at 1250 °C were investigated. The nominal compositions of the four alloys are Nb–15Si–24Ti–4Cr–2Al–2Hf–xDy (at.%), where x = 0, 0.05, 0.10 and 0.15, respectively. Results showed that the four alloys all consisted of Nbss, αNb5Si3 and γNb5Si3, and the addition of Dy produced no obvious effect on the phase constitution and the microstructures of Nb–Si-based alloys. After oxidation at 1250 °C for 58 h, it was found that the addition of Dy accelerated the oxidation rate of Nb–Si-based alloys and caused a larger weight gain, accompanied by the formation of a more porous and less protective oxide scale. The oxides of Nb2O5, Ti2Nb10O29, TiNb2O7, Ti0.4Cr0.3Nb0.3O2 and glassy SiO2 were formed on Dy-doped Nb–Si-based alloys. The high-temperature oxidation mechanism of Dy-doped Nb–Si-based alloys was discussed.

After a two-step heat treatment, the Cr2Nb particles in a directionally solidified Nb-24Ti-12Si-10Cr-2Al-2Hf (at pct, unless stated otherwise) alloy were substantially refined into nanoscale precipitates. These precipitates showed the following orientation relationship with the NbSS matrix: (111)Nb//(111)Cr2Nb, [110]Nb//[220]Cr2Nb. The formation of nanoscale Cr2Nb particles via an aging heat treatment at 1273 K (1000 °C) improved the tensile strength to 950 MPa and reduced the alloy weight gain from 218.27 to 144.41 mg/cm2.

In this study, the effect of holding pressure on microstructure and mechanical properties of low-pressure die cast A356 aluminum alloy was investigated. The results showed that the application of high holding pressure (300 kPa) generated castings with denser structure and superior mechanical properties. By increasing the holding pressure up to 300 kPa, the size of secondary dendrite arm spacing greatly reduced by 22.7% at the cooling rate of 1°C/s and decreased by 12.8% at 10°C/s. The Feret’s diameter and aspect ratio of eutectic silicon particles decreased by 8.4 and 5.1% at the cooling rate of 1°C/s and decreased by 9.3 and 6.4% at 10°C/s, respectively. Meanwhile, the density of A356 aluminum alloy increased to 2.678 g/cm3 and the area fraction of porosity decreased to 0.035%. Thus, tensile properties of A356 aluminum alloy obtained at high holding pressure were enhanced, especially the ductility. All these could be associated with the better filling capability and faster cooling rate caused by high holding pressure. In the analytical range of experimental conditions, the correlation of mechanical properties with process parameters was established by statistical models to predict the ultimate tensile strength and elongation of low-pressure die cast A356 aluminum alloy.

Spherical Nb–20Si–24Ti–2Cr–2Al pre-alloyed powders were processed by selective laser melting (SLM) on Ti6Al4V substrates with different energy densities. A series of single tracks and single layers were produced using different processing parameters, including powder size, laser power, scanning speed and hatch distance. Results showed that the pre-alloyed powders ranging from 45 to 75 μm were more applicable to SLM with less balling tendency, in comparison with those between 75 and 180 μm. The increase in linear energy density (LED) resulted in the decrease in contact angle and the increase in the width of single track as well as its penetration depth into the substrate. Smaller hatch distance leaded to a larger remelted part of the former track and a higher volumetric laser energy density. With a thickness of 75.6 μm, an interfacial intermediate layer, enriched in Ti and depleted in Nb, Si, Cr and Al, was formed between the SLM part and the Ti6Al4V substrate. The mechanisms of the elimination of balling phenomenon by employing a higher LED and the interfacial bonding characteristics between Nb–Si-based alloys via SLM and the Ti6Al4V substrate were discussed.

Our prior experience heavily influences our subjective time. One of such phenomena is repetition compression, that is, repeated stimuli are perceived shorter than novel stimuli. However, most of the studies on repetition compression used identical stimuli, leaving the question whether similar repetition effects could take place in phonological and semantic level repetition. We used Chinese characters to manipulate different levels of repetition in a duration discrimination task. We replicated earlier findings that repetition of visual identical characters shortened the apparent duration and found the repetition compression was spatially independent. Phonological repetition also caused the duration compression though the effect was weaker than the visual repetition. However, we observed no duration compression during the semantic repetition. The results suggest that repetition compression is mediated by visual and phonological representation of a stimulus in an early stage in processing hierarchy. We explained our findings according to the framework of predictive coding.

The microstructure and oxidation behavior of directionally solidified (DS) Nb–15Si–24Ti–4Cr–2Al–2Hf alloys with separate vanadium, tantalum, tungsten and zirconium additions were investigated by X-ray diffraction (XRD), electron probe microanalyzer (EPMA) equipped with wave-dispersive spectroscopy (WDS), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) equipped with an energy-dispersive spectroscopy (EDS). Results show that the five alloys are all composed of primary (Nb,Ti) solid solution ((Nb,Ti)SS) phase and eutectic (Nb,Ti)SS/(Nb,Ti)5Si3 structure. After oxidation at 1250 °C for 100 h in air, the surfaces of the five alloys are covered by the oxides of Nb2O5, TiNb2O7, Ti2Nb10O29, TiO2 and amorphous SiO2. It is found that the alloying elements of V and W are detrimental for oxidation resistance and the addition of Ta has no obvious effect. Zr addition obviously benefits the oxidation resistance at high temperature, by decreasing the weight gain from 242.75 to 184.83 mg·cm−2. The oxidation mechanism of Nb–Si-based alloys and the effects of different alloying elements on the oxidation resistance of Nb–Si-based alloys were discussed.

High-temperature oxidation behavior of directionally solidified (DS) Nb–Si-based alloys with Re additions was investigated at 1200 and 1250 °C, respectively. Microstructures and high-temperature oxidation behavior of the alloys were characterized. Results show that the microstructures in vertical section of Nb–24Ti–15Si–4Cr–2Al–2Hf–xRe (x = 0, 1, 3; at%) alloys grow parallel to the withdrawal direction and the cross section exhibits bud-like structures. The bud-like structures become finer with more Re additions. The weight gain of the Nb–24Ti–15Si–4Cr–2Al–2Hf–3Re alloy after oxidation at 1200 °C for 100 h is 198.1 mg·cm−2, and it is a bit higher at 1250 °C. The other two alloys perform somewhat worse. The influence of Re addition on the oxidation resistance at 1250 °C is more significant than that at 1200 °C. Although Re addition does not benefit obviously the high-temperature oxidation resistance of the DS samples, it does not compromise the oxidation resistance with a certain amount of Re additions in contrast with the alloy without Re addition.

In this work, the near-eutectic Nb–24Ti–15Si–4Cr–2Al–2Hf (at%) alloy was directionally solidified at 1900 °C with withdrawal rates of 6, 18, 36, 50 mm·min−1 and then heat-treated at 1450 °C for 12 h. The microstructure evolution was investigated. The results show that the microstructure of the directionally solidified (DS) alloy is composed of Nbss + Nb5Si3 eutectics within the whole withdrawal rate range, while the variation of rates makes a great difference on the solidification routes, the morphology and size of Nbss + Nb5Si3 eutectic cells. With the increase in withdrawal rates, the petaloid Nbss + Nb5Si3 eutectic cells transform into granular morphology. After the heat treatment, a mesh structure Nbss is formed gradually which isolates the Nb5Si3, and the phase boundaries become smoother in order to reduce the interfacial energy. Moreover, two kinds of Nb5Si3 exist in the heat-treated (HT) samples identified by crystal form and element composition, which are supposed as α-Nb5Si3 and γ-Nb5Si3, respectively. This study exhibits significant merits in guiding the optimization of Nb–Si-based alloys’ mechanical properties.

Nb–24Ti–18Si–2Al–2Hf–4Cr and Nb–24Ti–18Si–2Al–2Hf–8Cr alloys were prepared by arc melting in a water-cooled crucible under argon atmosphere. Microstructural characteristics and oxidation resistance of the alloys at 1250 °C were investigated. The results show that, when the Cr content is 4 at%, the microstructures consist of (Nb,Ti)SS and Nb5Si3; as Cr content increases to 8 at%, C14 Laves phase Cr2Nb is formed. The isothermal oxidation tests show that the oxidation kinetics of the two alloys follow similar features. The weight gains of the two alloys after oxidation at 1250 °C for 100 h are 235.61 and 198.50 mg·cm−2, respectively. During oxidation, SiO2, TiO2, Nb2O5 and CrNbO4 are formed at first. Then, Ti2Nb10O29 is formed after oxidation for 20 min and begins to change into TiNb2O7 as the oxidation proceeds. SiO2 is formed as solid state at first but later evolves into glassy state to improve the cohesion of the scale. After oxidation for 100 h, oxidation products consist of SiO2, TiNb2O7, Nb2O5 and CrNbO4.

When two identical visual discs move toward each other on a two-dimensional visual display, they can be perceived as either “streaming through” or “bouncing off” each other after their coincidence. Previous studies have observed a strong bias toward the streaming percept. Additionally, the incidence of the bouncing percept in this ambiguous display could be increased by various factors, such as a brief sound at the moment of coincidence and a momentary pause of the two discs. The streaming/bouncing bistable motion phenomenon has been studied intensively since its discovery. However, little is known regarding the neural basis underling the perceptual ambiguity in the classic version of the streaming/bouncing motion display. The present study investigated the neural basis of the perception disambiguating underling the processing of the streaming/bouncing bistable motion display using event-related potential (ERP) recordings. Surprisingly, the amplitude of frontal central P2 (220–260 ms) that was elicited by the moving discs ~200 ms before the coincidence of the two discs was observed to be predictive of subsequent streaming or bouncing percept. A larger P2 amplitude was observed for streaming percept than the bouncing percept. These findings suggest that the streaming/bouncing bistable perception may have been disambiguated unconsciously ~200 ms before the coincidence of the two discs.

X-ray diffraction analysis, scanning electron microscopy, and transmission electron microscopy were used to investigate the microstructures and orientation relationships (ORs) of Nb-16Si-22Ti-2Al-2Hf-(2,17)Cr alloys (hereafter referred to as 2Cr and 17Cr alloys, respectively). The mechanical properties of the two alloys at room and/or high temperatures were compared. The 2Cr alloy comprised NbSS and (α + β)-Nb5Si3 phases, while the 17Cr alloy consisted of NbSS, (α + β)-Nb5Si3 and Laves Cr2Nb phases with a C15 structure. The β-Nb5Si3 and Laves Cr2Nb phases exhibited variable ORs with respect to the NbSS phase. The Laves Cr2Nb phase was found to play a negative role on the fracture toughness at room temperature and on the compressive strength at temperatures from 1523 K to 1623 K (1250 °C to 1350 °C). The fracture toughness and the compressive yield strength at 1623 K (1350 °C) both decreased from 14.4 to 10.3 MPa m1/2 and from 300 to 85 MPa, respectively, when the nominal Cr content increased from 2 to 17 at. pct. Finally, the fracture modes of these typical NbSS/Nb5Si3 and NbSS/Nb5Si3/Cr2Nb microstructures under bending and compression conditions at room and high temperatures were investigated and discussed.

The surface properties of glass fiber were quantificationally analyzed by inverse gas chromatography (IGC). Five n-alkanes (C6, C7, C8, C9, and C10) were chosen as apolar probes to characterize the dispersive component of surface free energy. Trichloromethane (CHCl3), acetone, and tetrahydrofuran (THF) were chosen as polar probes to detect the Lewis acid-base parameters. It is found that the dispersive components of free energy are 32.3, 30.5, 27.5, and 26.9 mJ/m2 at 70, 80, 90, and 100 °C, respectively. The Lewis acidic number Ka of the glass fiber is 0.512 4, and the basic number Kb is 2.862. The results mean the glass fiber is a Lewis basic material.

Manganese dioxide crystallite and its composite hybridized with graphene nanoribbons (GNRs) are prepared by hydrothermal method. The effects of reaction temperature and time, surfactant, and reducing Mn resource are discussed. As the cathode material for Li battery, γ-MnO2 nanowire/nanorod hybridizing with (GNRs) (γ-MnO2/GNRs) shows a higher discharge specific capacity than it covering with carbon nanotubes or graphene sheets. In addition, the discharge specific capacity of γ-MnO2/GNRs is much higher than those of pure β-MnO2 and compact β-MnO2/GNRs. The effects of crystal size, morphology, and GNR hybrid on the discharge specific capacity are discussed.