Tribological Properties of Blocky Composites with Carbon Nanotubes.

A large amount of primary energy is lost due to friction, and the study of new additive materials to improve friction performance is in line with the concept of low carbon. Carbon nanotubes (CNTs) have advantages in drag reduction and wear resistance with their hollow structure and self-lubricating properties. This review investigated the mechanism of improving friction properties of blocky composites (including polymer, metal, and ceramic-based composites) with CNTs' incorporation. The characteristic tubular structure and the carbon film make low wear rate and friction coefficient on the surface. In addition, the effect of CNTs' aggregation and interfacial bond strength on the wear resistance was analyzed. Within an appropriate concentration range of CNTs, the blocky composites exhibit better wear resistance properties. Based on the differences in drag reduction and wear resistance in different materials and preparation methods, further research directions of CNTs have been suggested.

A Fluorous Peptide Amphiphile with Potent Antimicrobial Activity for the Treatment of MRSA-induced Sepsis and Chronic Wound Infection.

The rising prevalence of global antibiotic resistance evokes the urgent need for novel antimicrobial candidates. Cationic lipopeptides have attracted much attention due to their strong antimicrobial activity, broad-spectrum and low resistance tendency. Herein, a library of fluoro-lipopeptide amphiphiles was synthesized by tagging a series of cationic oligopeptides with a fluoroalkyl tail via a disulfide spacer. Among the lipopeptide candidates, R6F bearing six arginine moieties and a fluorous tag shows the highest antibacterial activity, and it exhibits an interesting fluorine effect as compared to the non-fluorinated lipopeptides. The high antibacterial activity of R6F is attributed to its excellent bacterial membrane permeability, which further disrupts the respiratory chain redox stress and cell wall biosynthesis of the bacteria. By co-assembling with lipid nanoparticles, R6F showed high therapeutic efficacy and minimal adverse effects in the treatment of MRSA-induced sepsis and chronic wound infection. This work provides a novel strategy to design highly potent antibacterial peptide amphiphiles for the treatment of drug-resistant bacterial infections.

CD300ld on neutrophils is required for tumour-driven immune suppression.

The immune-suppressive tumour microenvironment represents a major obstacle to effective immunotherapy1,2. Pathologically activated neutrophils, also known as polymorphonuclear myeloid-derived suppressor cells (PMN-MDSCs), are a critical component of the tumour microenvironment and have crucial roles in tumour progression and therapy resistance2-4. Identification of the key molecules on PMN-MDSCs is required to selectively target these cells for tumour treatment. Here, we performed an in vivo CRISPR-Cas9 screen in a tumour mouse model and identified CD300ld as a top candidate of tumour-favouring receptors. CD300ld is specifically expressed in normal neutrophils and is upregulated in PMN-MDSCs upon tumour-bearing. CD300ld knockout inhibits the development of multiple tumour types in a PMN-MDSC-dependent manner. CD300ld is required for the recruitment of PMN-MDSCs into tumours and their function to suppress T cell activation. CD300ld acts via the STAT3-S100A8/A9 axis, and knockout of Cd300ld reverses the tumour immune-suppressive microenvironment. CD300ld is upregulated in human cancers and shows an unfavourable correlation with patient survival. Blocking CD300ld activity inhibits tumour development and has synergistic effects with anti-PD1. Our study identifies CD300ld as a critical immune suppressor present on PMN-MDSCs, being required for tumour immune resistance and providing a potential target for cancer immunotherapy.

A Stacked FKM/PU Triboelectric Nanogenerator for Discrete Mechanical Energy Harvesting.

To combine the advantages of elastic and nonelastic triboelectric materials, this work proposes a new type of triboelectric nanogenerator (TENG) based on stacking -the stacked FKM/PU TENG. By stacking the elastomer polyurethane (PU) and the nonelastomer fluororubber (FKM), the FKM/PU TENG combines the inherent triboelectric characteristics of both materials and the unique elasticity of PU to achieve an output performance that is much higher than that of the FKM-TENG or the PU-TENG. The maximum instantaneous open-circuit voltage and short-circuit current of the FKM/PU TENG reach 661 V and 71.2 µA, respectively. Under the limiting conditions of 3 Hz and maximum compression, this device can attain a maximum power density of 49.63 W/m3 and light more than 500 LEDs. Therefore, stacking materials with different properties gives the FKM/PU TENG high output performance and great application potential, which can contribute to future development of discrete mechanical energy harvesting.

Efficient expansion of mouse hematopoietic stem cells ex vivo by membrane anchored Angptl2.

Hematopoietic stem cell (HSC) transplantation represents an important curative therapy for numerous hematological and immune diseases. Many efforts have been applied to achieve attainable ex vivo HSC expansion. We previously showed that angiopoietin-like proteins 2 (Angptl2) binds and activates the immune inhibitory receptor human leukocyte immunoglobulin (Ig)-like receptor B2 (LILRB2) to support the expansion of HSC. However, soluble Angptl2 is unstable and the downstream signaling would be attenuated by ligand-binding triggered receptor endocytosis, compromising the potential of Angptl2 to expand HSCs. We proposed that membrane anchored Angptl2 will overcome these limitations. In this study, we constructed the C-terminal and N-terminal anchored membrane Angptl2 (Cm-Angptl2 and Nm-Angptl2) by adding a transmembrane domain at the C-terminal or an anchor sequence at the N-terminal respectively. Both forms of Angptl2 showed efficient expression on the surface of feeder cells. Nm-Angptl2, but not Cm-Angptl2, induces a potent activation of LILRB2 reporter, indicating the fibronectin (FBN) domain at the C-terminus of Angptl2 is essential to stimulate LILRB2 signaling. Compared to soluble Angptl2, Nm-Angptl2 displays higher activities to activate LILRB2 reporter, and to promote the expansion of mouse HSCs as determined by transplantation and limiting dilution assay. Our study revealed the importance of FBN domain for Angptl2 to activate LILRB2 and demonstrated that Nm-Angptl2 have enhanced activities than the soluble protein in LILRB2 activation and HSC expansion, providing a strategy to explore the mode of ligand induced receptor signaling, and an optimized approach to expand HSCs ex vivo.

Effect of Bionic Nonsmooth Surface Vane on the Antiwear Characteristics of Double-Vane Pump.

In order to improve the antiwear characteristics of the double-vane self-priming pump, the surface structure of the Scapharca subcrenata was extracted and reconstructed according to bionic principles. Three types of nonsmooth surface models were established at the outlet end of the suction surface of the vanes, which is the most severely worn in the double-vane pump. The external characteristics, pressure field distribution, wear area distribution, and wear degree of the volute and vanes at different concentrations of nonsmooth vane structure were investigated by numerical simulation to reveal the mechanism of the nonsmooth surface structure of the wear characteristics of the vanes. The results show that the head and efficiency of pumps with four different vanes decrease and the average wear rate increases as the particle concentration increases. The different vane structures have a very small effect on the wear resistance of the volute, but a larger effect on vane wear. The circular nonsmooth surface structure, which reduces the low pressure area of the inlet section of the impeller while ensuring a smaller drop in head and efficiency, produces the best antiwear effect and improves the antiwear performance of the double-vane pump.

Preparation and Modification Technology Analysis of Ionic Polymer-Metal Composites (IPMCs).

As a new type of flexible smart material, ionic polymer-metal composite (IPMC) has the advantages of being lightweight and having fast responses, good flexibility, and large deformation ranges. However, IPMC has the disadvantages of a small driving force and short lifespan. Based on this, this paper firstly analyzes the driving mechanism of IPMC. Then, it focuses on the current preparation technology of IPMC from the aspects of electroless plating and mechanical plating. The advantages and disadvantages of various preparation methods are analyzed. Due to the special driving mechanism of IPMC, there is a problem of short non-aqueous working time. Therefore, the modification research of IPMC is reviewed from the aspects of the basement membrane, working medium, and electrode materials. Finally, the current challenges and future development prospects of IPMC are discussed.

Slime-Groove Drag Reduction Characteristics and Mechanism of Marine Biomimetic Surface.

With the development of science and technology, energy consumption and demand continue to increase, and energy conservation and consumption reduction have become the primary issue facing the world. Improving the energy efficiency of ships not only helps reduce fuel consumption but also reduces carbon dioxide emissions, which is an important guarantee for the green development of the ocean and the maintenance of ecological balance. Through natural selection and adaptation to the environment after evolution, the body surface of organisms generates a variety of ways to resist adhesion and resistance of Marine organisms. Through the study of fish organisms, it is found that the body surface of general fish has mucus, which can effectively reduce the friction resistance of the body surface of fish subjected to seawater. In addition, the grooves on the body surface also help to reduce the resistance between swimming organisms and fluids. Based on the principle of bionics, the drag reduction characteristics and mechanism of fish surface mucus were analyzed. The drag reduction mechanism of bionic nonsmooth surface is analyzed from the aspect of body surface structure. On the basis of the two approaches, the characteristics and mechanism of slime and groove codrag reduction on the surface of Marine organisms were discussed in depth, so as to obtain a better new drag reduction method and provide reference for subsequent related research.

Receptome profiling identifies KREMEN1 and ASGR1 as alternative functional receptors of SARS-CoV-2.

Host cellular receptors play key roles in the determination of virus tropism and pathogenesis. However, little is known about SARS-CoV-2 host receptors with the exception of ACE2. Furthermore, ACE2 alone cannot explain the multi-organ tropism of SARS-CoV-2 nor the clinical differences between SARS-CoV-2 and SARS-CoV, suggesting the involvement of other receptor(s). Here, we performed genomic receptor profiling to screen 5054 human membrane proteins individually for interaction with the SARS-CoV-2 capsid spike (S) protein. Twelve proteins, including ACE2, ASGR1, and KREMEN1, were identified with diverse S-binding affinities and patterns. ASGR1 or KREMEN1 is sufficient for the entry of SARS-CoV-2 but not SARS-CoV in vitro and in vivo. SARS-CoV-2 utilizes distinct ACE2/ASGR1/KREMEN1 (ASK) receptor combinations to enter different cell types, and the expression of ASK together displays a markedly stronger correlation with virus susceptibility than that of any individual receptor at both the cell and tissue levels. The cocktail of ASK-related neutralizing antibodies provides the most substantial blockage of SARS-CoV-2 infection in human lung organoids when compared to individual antibodies. Our study revealed an interacting host receptome of SARS-CoV-2, and identified ASGR1 and KREMEN1 as alternative functional receptors that play essential roles in ACE2-independent virus entry, providing insight into SARS-CoV-2 tropism and pathogenesis, as well as a community resource and potential therapeutic strategies for further COVID-19 investigations.

Research Strategies to Develop Environmentally Friendly Marine Antifouling Coatings.

There are a large number of fouling organisms in the ocean, which easily attach to the surface of ships, oil platforms and breeding facilities, corrode the surface of equipment, accelerate the aging of equipment, affect the stability and safety of marine facilities and cause serious economic losses. Antifouling coating is an effective method to prevent marine biological fouling. Traditional organic tin and copper oxide coatings are toxic and will contaminate seawater and destroy marine ecology and have been banned or restricted. Environmentally friendly antifouling coatings have become a research hotspot. Among them, the use of natural biological products with antifouling activity as antifouling agents is an important research direction. In addition, some fouling release coatings without antifoulants, biomimetic coatings, photocatalytic coatings and other novel antifouling coatings have also developed rapidly. On the basis of revealing the mechanism of marine biofouling, this paper reviews the latest research strategies to develop environmentally friendly marine antifouling coatings. The composition, antifouling characteristics, antifouling mechanism and effects of various coatings were analyzed emphatically. Finally, the development prospects and future development directions of marine antifouling coatings are forecasted.

Nanoengineered targeting strategy for cancer immunotherapy.

Cancer immunotherapy is rapidly changing the paradigm of cancer care and treatment by evoking host immunity to kill cancer cells. As clinical approval of checkpoint inhibitors (e.g., ipilimumab and pembrolizumab) has been accelerated by a dramatic improvement of long-term survival in a small subset of patients compared to conventional chemotherapy, growing interesting research has focused on immunotherapy. However, majority of patients have not benefited from checkpoint therapies that only partially remove the inhibition of T cell functions. Insufficient systemic T cell responses, low immunogenicity and the immunosuppressive environment of tumors, create great challenges on therapeutic efficiency. Nanotechnology can integrate multiple functions within controlled size and shape, and has been explored as a unique avenue for the development of cancer immunotherapy. In this review, we mainly address how nanoengineered vaccines can induce robust T cell responses against tumors, as well as how nanomedicine can remodel the tumor immunosuppressive microenvironment to boost antitumor immune responses.

Research Progress on the Collaborative Drag Reduction Effect of Polymers and Surfactants.

Polymer additives and surfactants as drag reduction agents have been widely used in the field of fluid drag reduction. Polymer additives can reduce drag effectively with only a small amount, but they degrade easily. Surfactants have an anti-degradation ability. This paper categorizes the mechanism of drag reducing agents and the influencing factors of drag reduction characteristics. The factors affecting the degradation of polymer additives and the anti-degradation properties of surfactants are discussed. A mixture of polymer additive and surfactant has the characteristics of high shear resistance, a lower critical micelle concentration (CMC), and a good drag reduction effect at higher Reynolds numbers. Therefore, this paper focuses more on a drag reducing agent mixed with a polymer and a surfactant, including the mechanism model, drag reduction characteristics, and anti-degradation ability.

Research on the influence of elbow erosion characteristics based on bionic earthworm dorsal pore jet.

Based on the biological characteristics of earthworm, the dorsal pore jet parameters were analyzed to establish elbow erosion model. The discrete phase model and standard k-ε turbulence model were used to carry on numerical simulation of the erosion characteristics and study the mechanism of improving elbow erosion characteristics. The results showed that the most serious erosion area was the elbow lower surface, while bionic earthworm dorsal pore jet could significantly reduce the erosion rate of this area, thereby reducing the overall erosion rate. When the jet velocity was the same, the smaller the jet distance, the lower the erosion rate would be. With the increase of the jet velocity, the erosion rate decreased first and then increased. When the jet distance was 0.5 times the elbow diameter and the jet velocity was 0.3 times the flow velocity, the erosion rate was the lowest (decreased by 79.29%). When the jet velocity was less than 0.5 m·s-1, low-velocity strips formed at elbow lower surface due to the jet and reduced the kinetic energy of the solid particles near the wall; when the jet velocity was greater than 0.2 times the flow velocity, vortex cushion effect formed, therefore reduced the erosion rate significantly.

Experiment Research on Hot-Rolling Processing of Nonsmooth Pit Surface.

In order to achieve the nonsmooth surface drag reduction structure on the inner polymer coating of oil and gas pipelines and improve the efficiency of pipeline transport, a structural model of the machining robot on the pipe inner coating is established. Based on machining robot, an experimental technique is applied to research embossing and coating problems of rolling-head, and then the molding process rules under different conditions of rolling temperatures speeds and depth are analyzed. Also, an orthogonal experiment analysis method is employed to analyze the different effects of hot-rolling process apparatus on the embossed pits morphology and quality of rolling. The results also reveal that elevating the rolling temperature or decreasing the rolling speed can also improve the pit structure replication rates of the polymer coating surface, and the rolling feed has little effect on replication rates. After the rolling-head separates from the polymer coating, phenomenon of rebounding and refluxing of the polymer coating occurs, which is the reason of inability of the process. A continuous hot-rolling method for processing is used in the robot and the hot-rolling process of the processing apparatus is put in a dynamics analysis.