Purpose
The purpose of this paper is to describe the tribological characteristics with different area density of concave-convex micro-texture on the mold surface. It is a new technology to improve ...the quality of the workpiece to control the tribological properties through the application of concave-convex micro-texture on the mold surface.
Design/methodology/approach
Five groups of laser micro-texture with different area density (ratio of the concave-convex micro-texture area to the all-area) were processed on the surface of the mold steel, and the tribological properties were compared with the smooth surface of the reference sample.
Findings
The time of the running-in stage in different experimental groups was about 300 s. The fluctuation amplitude of concave-convex micro-texture friction coefficient is much larger than that of smooth plane specimen in the running-in stage. After the running-in stage, the friction coefficients were lower than that in the smooth condition and decreased with the increase of the concave-convex micro-texture area density. When the area density reached 25%, the friction coefficients no longer decreased significantly. In addition, the wear of concave-convex micro-texture surface is much lower than that of smooth surface and decreases with the increase of concave-convex micro-texture area density.
Originality/value
Domestic and foreign scholars have done a lot of research on the relationship between concave micro-texture and tribological properties. However, the object of this paper is a new concave-convex micro-texture, which is rarely studied in the field of tribology.
Peer review
The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-03-2020-0081/
In order to enhance the lipophilicity and thus oral bioavailability of icariin (ICA) and icariside II (ICA II) of total flavonoids of epimedium (TFE), a total flavonoids of epimedium–phospholipid ...complex (TFE‐PLC) is prepared by wet media milling. The stabilizers Aerosi and SDS are used to formulate TFE‐PLC nanosuspensions (TFE‐PLC–Ns) to improve the dispersion of TFE–PLC. FTIR and DSC data confirms the formation of TFE‐PLC. The oil solubility of ICA and ICA II in the complex in octanol is improved nearly four times over that in TFE. The logP of ICA in TFE‐PLC is significantly increased with a value from 1.61 to 2.02 at pH 4.5, and ICA II, from 3.24 to 4.77. The mean diameter of the TFE‐PLC‐Ns is reduced from 6.166 to 0.424 μm, and its dissolution is improved over TFE. In the in vivo evaluation, TFE‐PLC‐Ns exhibits a considerable enhancement with larger AUC0–t and shorter Tmax than TFE and TFE‐PLC. The relative bioavailability of ICA in TFE‐PLC and TFE‐PLC‐Ns are 181.75 and 249.05%, respectively, and for ICA II are 401.63 and 684.70%, respectively. Therefore, it suggests that TFE‐PLC‐Ns has possibilities in enhancing oral bioavailability of TFE, which may be due to its improved lipophilicity and wettability.
Practical Applications: The oral bioavailability of ICA and ICA II in TFE are very low due to their poor lipophilicity and cell permeability. Here, TFE‐PLC‐Ns is proposed, which is prepared by wet media milling for improving lipophilic properties and oral bioavailability. In addition, some proofs of TFE‐PLC are investigated in detail, and TFE‐PLC‐Ns significantly increased the oral bioavailability of ICA and ICA II in TFE. Therefore, the authors recommend a potential drug vehicle of TFE‐PLC‐Ns for oral administration of ICA and ICA II, and a novel method of phospholipid complex preparation for industrial manufacture.
In this article, the total flavonoids of epimedium–phospholipid complex (TFE‐PLC) is prepared to enhance the lipophilicity of icariin (ICA) and icariside II (ICA II) in TFE. Aerosi and SDS are used to formulate TFE‐PLC nanosuspensions (TFE‐PLC‐Ns) to improve the dispersion of TFE‐PLC. And finally, TFE‐PLC‐Ns exhibits enhanced oral bioavailability of ICA and ICA II compared with them in TFE and TFE‐PLC.
In this article, the total flavonoids of epimedium–phospholipid complex (TFE‐PLC) is prepared to enhance the lipophilicity of icariin (ICA) and icariside II (ICA II) in TFE. Aerosi and SDS are used to formulate TFE‐PLC nanosuspensions (TFE‐PLC‐Ns) to improve the dispersion of TFE‐PLC. And finally, TFE‐PLC‐Ns exhibits enhanced oral bioavailability of ICA and ICA II compared with them in TFE and TFE‐PLC.
The tailorable structure and electronic structure of metal–organic frameworks (MOFs) greatly facilitate their modulated light harvesting, redox power, and consequently photocatalysis. Herein, a ...representative MOF, UiO-66, was furnished by installing Fe3+ onto the Zr-oxo clusters, to give Fe-UiO-66, which features extended visible light harvesting, based on metal-to-cluster charge transfer (MCCT). The Fe-UiO-66 with unique electronic structure and strong oxidizing power exhibits visible light-driven water oxidation, which is impossible for pristine UiO-66. More strikingly, under visible irradiation, the generated holes over Fe-UiO-66 are able to exclusively convert H2O to hydroxide radicals, initiating and driving the activation of stubborn C-H bond, such as toluene oxidation. The electrons reduce O2 to O2 •‑ radicals that further promote the oxidation reaction. The related catalytic mechanism and the structure–activity relationship have been investigated in detail. As far as we know, this is not only an unprecedented report on activating “inert” MOFs for photocatalytic C-H activation but also the first work on extended light harvesting and enhanced photocatalysis for MOFs by introducing an MCCT process.
Intracerebral hemorrhage (ICH) is a disease with high disability and mortality rates. Currently, the efficacy of therapies available for ICH is limited. Microglia-mediated neuroinflammation ...substantially exacerbates brain damage following ICH. Here, we investigated whether mitochondrial uncouplers conferred protection by suppressing neuroinflammation following ICH. To mimic ICH-induced neuroinflammation in vitro, we treated microglia with red blood cell (RBC) lysate. RBC lysate enhanced the expression of pro-inflammatory cytokines in microglia. A clinically used uncoupler, niclosamide (Nic), reduced the RBC lysate-induced expression of pro-inflammatory cytokines in microglia. Moreover, Nic ameliorated brain edema, decreased neuroinflammation, and improved neurological deficits in a well-established mouse model of ICH. Like niclosamide, the structurally unrelated uncoupler carbonyl cyanide p-triflouromethoxyphenylhydrazone (FCCP) reduced brain edema, decreased neuroinflammation, and improved neurological deficits following ICH. It has been reported that mitochondrial uncouplers activate AMP-activated protein kinase (AMPK). Mechanistically, Nic enhanced AMPK activation following ICH, and AMPK knockdown abolished the beneficial effects of Nic following ICH. In conclusion, mitochondrial uncouplers conferred protection by activating AMPK to inhibit microglial neuroinflammation following ICH.
The development of highly specific and ultrasensitive fluorescent probes for tracking basal mitochondrial hypochlorite is very important to unravel its diverse cellular functions in the mitochondria ...of living cells. In this paper, we have developed a water-soluble, mitochondria-targeted near-infrared fluorescent probe NB-OCl for selectively measuring OCl- in the presence of higher concentration (500 μM) other biologically important substances. Surprisingly, the obtained results demonstrated that probe NB-OCl could sensitively determine OCl- in the range of 0–200 pM with the detection limit of 10.8 pM. To the best of our knowledge, NB-OCl is the first fluorescent probe for the specific determination of OCl- at the picomolar level. Moreover, probe NB-OCl exhibits a fast response for OCl- (< 5 s), which would be in favor of tracking the highly reactive and short-lived OCl- in the living systems. The preeminent recognition properties of probe NB-OCl enable its applications in the monitoring of basal OCl- and the fluctuations of endogenous/exogenous OCl- levels in the mitochondria of living cells.
•A mitochondria-targeted near-infrared fluorescent probe for OCl- was developed.•The probe could quantitatively and sensitively determine OCl- (DL = 10.8 pM).•The probe displayed preeminent selectivity toward OCl-.•The probe exhibited a fast response for OCl- (< 5 s).•The probe can monitor basal OCl- in the mitochondria of living cells.
Microplastics (MPs) are considered as a pollutant of marine environments and have become a global environmental problem in recent years. A number of studies have demonstrated that MPs can enter the ...human food chain, and MPs have even been detected in human stools. Therefore, there is increasing concern about the potential risks of MPs to human and animal health. Here, we investigated maternal polystyrene MPs exposure during gestation and lactation and evaluated the potential effects on dams and the F1 (both PND 42 and 280) and F2 (PND 42) generations. The results of transcriptome and 16S rRNA sequencing indicated that MPs caused the metabolic disorder in maternal MPs associated with gut microbiota dysbiosis and gut barrier dysfunction. Simultaneously, maternal MPs exposure also had the intergenerational effects and even caused long-term metabolic consequences in the F1 and F2 generations. In addition, in F1 (PND 42), the composition of gut microbiota did not change significantly, while the hepatic transcriptome and serum metabolite changes showed the potential risk in metabolic disorder. Then, the potential of hepatic lipid accumulation was observed in adult F1 mice (PND 280), especially in the female mice. Our results demonstrated that maternal MPs exposure during gestation and lactation increases the risk of metabolic disorder, and these results provide new insight into the potential long-term hazards of MPs.
Recently, research on graphene based photodetectors has drawn substantial attention due to ultrafast and broadband photoresponse of graphene. However, they usually have low responsivity and low ...photoconductive gain induced by the gapless nature of graphene, which greatly limit their applications. The synergetic integration of graphene with other two-dimensional (2D) materials to form van der Waals heterostructure is a very promising approach to overcome these shortcomings. Here we report the growth of graphene–Bi2Te3 heterostructure where Bi2Te3 is a small bandgap material from topological insulator family with a similar hexagonal symmetry to graphene. Because of the effective photocarrier generation and transfer at the interface between graphene and Bi2Te3, the device photocurrent can be effectively enhanced without sacrificing the detecting spectral width. Our results show that the graphene–Bi2Te3 photodetector has much higher photoresponsivity (35 AW–1 at a wavelength of 532 nm) and higher sensitivity (photoconductive gain up to 83), as compared to the pure monolayer graphene-based devices. More interestingly, the detection wavelength range of our device is further expanded to near-infrared (980 nm) and telecommunication band (1550 nm), which is not observed on the devices based on heterostructures of graphene and transition metal dichalcogenides.
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•A simple turn-on (654-fold enhancement) fluorescent probe for HOCl was developed.•The probe could quantitatively detect picomolar HOCl (DL = 17 pM).•The probe possessed preeminent ...selectivity toward HOCl.•The probe exhibited a fast response for HOCl (<3 s).•The probe was used to the fluorescence imaging of intracellular native HOCl.
Highly specific and ultrasensitive fluorescent probes for tracking the intracellular native hypochlorous acid (HOCl) levels are urgently needed owing to its important molecular functions in the biological systems. In this contribution, a simple thiocarbamate-caged 7-hydroxycoumarin (TCHC) was developed as fluorescent probe for monitoring HOCl in live cells. Probe TCHC exhibited preeminent specificity towards HOCl over other various bioactive substances. Importantly, probe TCHC could sensitively detect HOCl in the range of 0–175 pM with the detection limit of 17 pM, which was attributed to the multiple fluorescence sensing mechanisms including photo-induced electron transfer (PET), intramolecular charge transfer (ICT), and the chlorination. Furthermore, probe TCHC displayed an instant response towards HOCl (<3 s), and thus the real-time detection of HOCl could be achieved. Finally, probe TCHC was successfully applied to monitor native HOCl and the fluctuations of endogenous HOCl levels in live cells.
Herein, a signal output SERS aptasensor for Histamine (HA) detection is designed. MIL-100(Fe) was loaded with gold nanoparticles (AuNPs) to form composite nanozyme MIL-100(Fe)@AuNPs, which was used ...in the reaction system TMB/H
O
. Silver nanoparticles (AgNPs) were synthesized as "amplifier" for the SERS signal of ox TMB. After nucleic acid functionalization, the two parts were assembled to form the multifunctional substrate with both high catalytic and SERS efficiency. In the detection system, the specific binding effect of HA aptamer toward HA induced a decrease in the assembly of AgNPs on MIL-100(Fe)@AuNPs which caused a decrease in ox TMB SERS signals. The linear relation of HA ranged from 10
M to 5 × 10
M with LOD as low as 3.9 × 10
M. Recovery ratio in fermented soybean products (94.42-105.75 %) proved the real sample applicability. The fabricated SERS aptasensor will provide technical support for the safety during food processing and storage.
Coordination of diverse individuals often requires sophisticated communications and high-order computational abilities. Microbial populations can exhibit diverse individualistic behaviors, and yet ...can engage in collective migratory patterns with a spatially sorted arrangement of phenotypes. However, it is unclear how such spatially sorted patterns emerge from diverse individuals without complex computational abilities. Here, by investigating the single-cell trajectories during group migration, we discovered that, despite the constant migrating speed of a group, the drift velocities of individual bacteria decrease from the back to the front. With a Langevin-type modeling framework, we showed that this decreasing profile of drift velocities implies the spatial modulation of individual run-and-tumble random motions, and enables the bacterial population to migrate as a pushed wave front. Theoretical analysis and stochastic simulations further predicted that the pushed wave front can help a diverse population to stay in a tight group, while diverse individuals perform the same type of mean reverting processes around centers orderly aligned by their chemotactic abilities. This mechanism about the emergence of orderly collective migration from diverse individuals is experimentally demonstrated by titration of bacterial chemoreceptor abundance. These results reveal a simple computational principle for emergent ordered behaviors from heterogeneous individuals.
Organisms living in large groups often have to move together in order to navigate, forage for food, and increase their roaming range. Such groups are often made up of distinct individuals that must integrate their different behaviors in order to migrate in the same direction at a similar pace. For instance, for the bacteria
Escherichia coli
to travel as a condensed group, they must coordinate their response to a set of chemical signals called chemoattractants that tell them where to go.
The chemoattractants surrounding the bacteria are unequally distributed so that there is more of them at the front than the back of the group. During migration, each bacterium moves towards this concentration gradient in a distinct way, spontaneously rotating its direction in a ‘run-and-tumble’ motion that guides it towards areas where there are high levels of these chemical signals. In addition to this variability, how well individual bacteria are able to swim up the gradient also differs within the population. Bacteria that are better at sensing the chemoattractant gradient are placed at the front of the group, while those that are worst are shifted towards the back. This spatial arrangement is thought to help the bacteria migrate together. But how
E. coli
organize themselves in to this pattern is unclear, especially as they cannot communicate directly with one another and display such diverse, randomized behaviors.
To help answer this question, Bai, He et al. discovered a general principle that describes how single bacterial cells move within a group. The results showed that
E. coli
alter their run-and-tumble motion depending on where they reside within the population: individuals at the rear drift faster so they can catch up with the group, while those leading the group drift slower to draw themselves back. This ‘reversion behavior’ allows the migrating bacteria to travel at a constant speed around a mean position relative to the group.
A cell’s drifting speed is determined by how well it moves towards the chemoattractant and its response to the concentration gradient. As a result, the mean position around which the bacterium accelerates or deaccelerates will vary depending on how sensitive it is to the chemoattractant gradient. The
E. coli
therefore spatially arrange themselves so that the more sensitive bacteria are located at the front of the group where the gradient is shallower; and cells that are less sensitive are located towards the back where the gradient is steeper.
These findings suggest a general principle for how bacteria form ordered patterns whilst migrating as a collective group. This behavior could also apply to other populations of distinct individuals, such as ants following a trail or flocks of birds migrating in between seasons.
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