Comparative transcriptome analysis on the alteration of gene expression in ayu （Plecoglossus altivelis）larvae associated with salinity change

Ayu （Plecoglossus altivelis） fish, which are an amphidromous species distributed in East Asia, live in brackish water （BW） during their larval stage and in fresh water （FW） during their adult stage. In this study, we found that FW-acclimated ayu larvae exhibited a slower growth ratio compared with that of BW-acclimated larvae. However, the mechanism underlying FW acclimation on growth suppression is poorly known. We employed transcriptome analysis to investigate the differential gene expression of FW acclimation by RNA sequencing. We identified 158 upregulated and 139 downregulated transcripts in FW-acclimated ayu larvae compared with that in BW-acclimated larvae. As determined by Gene Ontology annotation and Kyoto Encyclopedia of Genes and Genomes pathway mapping, functional annotation of the genes covered diverse biological functions and processes, and included neuroendo- crinology, osmotic regulation, energy metabolism, and the cytoskeleton. Transcriptional expression of several differentially expressed genes in response to FW acclimation was further confirmed by real-time quantitative PCR. In accordance with transcriptome analysis, iodothyronine deiodinase （ID）, pro-opiom- elanocortin （POMC）, betaine-homocysteine S-meth- yltransferase 1 （BHMT）, fructose-bisphosphate aldolase B （aldolase B）, tyrosine aminotransferase （TAT）, and Na＋-K＋ ATPase （NKA） were upregulated after FW acclimation. Furthermore, the mRNA expressions of b-type natriurefic peptide （BNP） and transgelin were downregulated after FW acclimation. Our data indicate that FW acclimation reduced the growth rate of ayu larvae, which might result from the expression alteration of genes related to endocrine hormones, energy metabolism, and direct osmoregulation.

微米尺度与纳米尺度陶瓷颗粒等离子喷涂(APS)、超音速火焰喷涂(HVOF)、冷喷涂制备MCrAlY-Al_2O_3复合涂层的微结构与性能对比

陶瓷颗粒增强型金属基复合涂层在诸多工业领域都有需求,其中包括炼钢工业。本文中,MCr Al Y-Al2O3复合粉末通过球磨法制备,并且通过等离子喷涂、超音速火焰喷涂和冷喷涂分别制备了MCr Al Y-Al2O3复合涂层。实验结果显示,可以选用不优先使基体与Al2O3结合的复合粉末控制涂层中的Al2O3含量。涂层粉末的微结构在冷喷涂涂层和超音速火焰喷涂涂层中得到了良好的保留,这是因为喷涂粒子未熔化或部分熔化。然而,对于等离子喷涂的涂层,大多数Al2O3颗粒被隔离在层状界面,在条状界面上形成连续的氧化皮。经退火处理后,由元素扩散引起的条状界面的强化使得超音速火焰喷涂和大气等离子喷涂的涂层硬度增大。此外,冷喷涂涂层由于退火后加工硬化效果的消除,硬度增加不像超音速火焰喷涂和等离子喷涂涂层那样明显。

Durable dual-state duplex Si-HfO_(2)with excellent oxidation and cracking resistance

The lifetime of Si bond coatings in environmental barrier coatings is constrained by phase-transition-induced cracking of the SiO_(2)scale.In this study,Si-HfO_(2)dual-state duplex composite materials are proposed to address this issue by partially forming HfSiO_(4)and minimizing the SiO_(2)content.The as-prepared composite exhibited a structure comprising discrete HfO_(2)“bricks”embedded in a continuous Si“mortar”,while the oxidized state transformed into discrete HfSiO_(4)“bricks”within continuous thin SiO_(2)“mortars”.The results indicate that continuous thin SiO_(2)contributes to reducing the oxidation rate to a level comparable to that of pure Si,and discrete HfSiO_(4)particles aid in relieving phase transition-induced stress and inhibiting crack propagation,thereby enhancing oxidation and cracking resistance simultaneously.Consequently,the composite with 20 mol%HfO_(2)and a mean particle size of~500 nm at 1370℃exhibited a service lifetime 10 times greater than that of pure Si.This research provides valuable insights for designing Si-based bond coatings with improved service lifetime.

Boosting electromagnetic wave absorption of Ti_(3)AlC_(2) by improving effective electrical conductivity

Electromagnetic wave-absorbing(EMA)materials at high temperatures are limited by poor conduction loss(L_(c)).However,adding conductors simultaneously increases the conduction loss and interfacial polarization loss,leading to a conflict between impedance matching(Z_(in)/Z_(0))and electromagnetic wave loss.This will prevent electromagnetic waves from entering the EMA materials,finally reducing overall absorbing performance.Here,the effective electrical conductivity(σ)is enhanced by synchronizing particle size and grain number of Ti_(3)AlC_(2) to increase the conduction loss and avoid the conflict between the impedance matching and the electromagnetic wave loss.As a result,the best-absorbing performance with an effective absorption bandwidth(EAB)of 4.8 GHz(10.6–15.4 GHz)at a thickness of only 1.5 mm is realized,which is the best combination of wide absorption bandwidth and small thickness,and the minimum reflection loss(RL_(min))reaches−45.6 dB at 4.1 GHz.In short,this work explores the regulating mechanism of the EMA materials of effective electrical conductivity by simulated calculations using the Vienna ab-initio Simulation Package(VASP)and COMSOL as well as a series of experiments,which provide new insight into a rational design of materials with anisotropic electrical conductivity.

Heterogeneous layered structure in thermal barrier coatings by plasma spray-physical vapor deposition

The unique columnar structure endows thermal barrier coatings(TBCs)prepared by plasma spray-physical vapor deposition(PS-PVD)with high thermal insulation and long lifetime.However,the coating delamination failure resulting from an intra-column fracture(within a column rather than between columns)is a bottleneck in the solid dust particle impact environment for aero-engine.To clarify the intra-column fracture mechanism,a basic layer deposition model is developed to explore a heterogeneous weak-to-strong layered structure formed by a local transient in-situ deposit temperature.During the PS-PVD,an in-situ deposit surface is continuously updated due to constantly being covered by vapor condensation,showing a transient temperature,which means that the in-situ deposit surface temperature rises sharply in short period of 0.2 s of depositing a thin layer during a single pass.Meanwhile,the increasing temperature of the in-situ deposit surface results in an experimentally observed heterogeneous weak-to-strong structure,showing a continuous transition from a porous weak structure at the bottom region to a dense strong structure at the top region.This structure easily makes the intra-column fracture at the porous weak region.The results shed light on improving TBC lifetime by restraining the intra-column fracture.

Tailoring sintering-resistant thermal barrier coatings by considering critical healing width of two-dimensional interlamellar pores

Large degradation in thermal insulation and strain tolerance is a main headache and a primary cause of the failure for plasma-sprayed thermal barrier coatings(TBCs)during service.One mechanism behind such degradation is the healing of interlamellar pores formed by multiple connections between edges of a pore,which significantly speeds up healing during thermal exposure.The objective of this study is to obtain sintering-resistant TBCs by tailoring the width of interlamellar pores to avoid multiple connections.Firstly,the mechanism responsible for the multiple connections was revealed.The splat surfaces before and after thermal treatments were characterized via an atomic force microscope(AFM).The roughening of the pore surface occurs during thermal exposure,along with the grain growth inside the splats.Consequently,the local surface height increases,which causes multiple connections and healing of the interlamellar pores.Secondly,critical widths of the interlamellar pores for avoiding the multiple connections during thermal exposure are established by correlating the extent of surface roughening with the growth of individual grains.The height increase of the splat surface and the growth of the grain size(D)were found to increase with the exposure temperature and duration.A relationship linking the height increase and the growth of the grain size induced by thermal exposure in plasma-sprayed ceramic splats was obtained.Finally,composite TBCs were prepared to form wide interlamellar pores in the coatings.Using this design,the increases in the thermal conductivity(λ)and the elastic modulus(E)can be prevented to a large extent.Thus,sintering-resistant TBCs that maintain high thermal insulation and strain tolerance,even afer long thermal exposure,can be created.

Epitaxial growth and cracking of highly tough 7YSZ splats by thermal spray technology

Thermally sprayed coatings are essentially layered materials and contain large numbers of lamellar pores. It is thus quite necessary to clarify the formation mechanism of lamellar pores which significantly influence coating performances. In the present study, to elaborate the formation mechanism of lamellar pores, the yttria-stabilized zirconia(ZrO_2–7 wt% Y_2O_3, 7YSZ) splats, which have high fracture toughness and tetragonal phase stability, were employed. Interestingly, anomalous epitaxial growth occurred for all deposition temperatures in spite of the extremely high cooling rate,which clearly indicated chemical bonding and complete contact at splat/substrate interface before splat cooling. However, transverse spallation substantially occurred for all deposition temperatures in spite of the high fracture toughness of 7YSZ, which revealed that the lamellar pores were from transverse cracking/spallation due to the large stress during splat cooling. Additionally, fracture mechanics analysis was carried out, and it was found that the stress arose from the constraint effect of the shrinkage of the splat by locally heated substrate with the value about 1.97 GPa. This clearly demonstrated that the stress was indeed large enough to drive transverse cracking/spallation forming lamellar pores during splat cooling. All of these contribute to understanding the essential features of lamellar bonding and further tailoring the coating structures and performance.

Progress in ceramic materials and structure design toward advanced thermal barrier coatings

Thermal barrier coatings(TBCs)can effectively protect the alloy substrate of hot components in aeroengines or land-based gas turbines by the thermal insulation and corrosion/erosion resistance of the ceramic top coat.However,the continuous pursuit of a higher operating temperature leads to degradation,delamination,and premature failure of the top coat.Both new ceramic materials and new coating structures must be developed to meet the demand for future advanced TBC systems.In this paper,the latest progress of some new ceramic materials is first reviewed.Then,a comprehensive spalling mechanism of the ceramic top coat is summarized to understand the dependence of lifetime on various factors such as oxidation scale growth,ceramic sintering,erosion,and calcium–magnesium–aluminium–silicate(CMAS)molten salt corrosion.Finally,new structural design methods for high-performance TBCs are discussed from the perspectives of lamellar,columnar,and nanostructure inclusions.The latest developments of ceramic top coat will be presented in terms of material selection,structural design,and failure mechanism,and the comprehensive guidance will be provided for the development of next-generation advanced TBCs with higher temperature resistance,better thermal insulation,and longer lifetime.

Plasma spray-physical vapor deposition toward advanced thermal barrier coatings:a review

Plasma spray–physical vapor deposition(PS–PVD)is a unique technology that enables highly tailorable functional films and coatings with various rare metal elements to be processed.This technology bridges the gap between conventional thermal spray and vapor deposition and provides a variety of coating microstructures composed of vapor,liquid,and solid deposition units.The PS–PVD technique serves a broad range of applications in the fields of thermal barrier coatings(TBCs),environmental barrier coatings(EBCs),oxygen permeable films,and electrode films.It also represents the development direction of high-performance TBC/EBC preparation technologies.With the PS–PVD technique,the composition of the deposition unit determines the microstructure of the coating and its performance.When coating materials are injected into a nozzle and transported into the plasma jet,the deposition unit generated by a coating material is affected by the plasma jet characteristics.However,there is no direct in situ measurement method of material transfer and deposition processes in the PS–PVD plasma jet,because of the extreme conditions of PS–PVD such as a low operating pressure of*100 Pa,temperatures of thousands of degrees,and a thin and high-velocity jet.Despite the difficulties,the transport and transformation behaviors of the deposition units were also researched by optical emission spectroscopy,observation of the coating microstructure and other methods.This paper reviews the progress of PS–PVD technologies considering the preparation of advanced thermal barrier coatings from the perspective of the transport and transformation behaviors of the deposition units.The development prospects of new high-performance TBCs using the PS–PVD technique are also discussed.

Bimodal TBCs with low thermal conductivity deposited by a powder-suspension co-spray process

Advanced thermal harrier coatings （TBCs） with better thermal barrier performance are required by both advanced gas turbine and air engine. In this work, novel bimodal TBCs with low thermal conductivity were deposited and characterized by a novel co-spray approach with both solid powder and suspension. Experimental and finite element analyses were used to optimize the process parameters to prepare the specific morphology nanostructure features. With a comprehensive understanding on the influence of spraying parameters on the morphology ofnano-particles, homogeneous nano-particle heaps with a large aspect ratio were introduced to conventional layered coatings by plasma co-spraying with suspension and solid powder. Co-sprayed bimodal microstructure composite coatings resulted from both wet suspension droplets and molten particle droplets exhibited low thermal conductivity. The thermal conductivity of the composite coating was 1/5 lower than that of the counterpart coatings by conventional plasma spraying with solid powder. This study sheds light to the structural tailoring towards the advanced TBCs with low thermal conductivity.

Highly stable carbon-based perovskite solar cell with a record efficiency of over 18% via hole transport engineering

Carbon-based perovskite solar cells show great potential owing to their low-cost production and superior stability in air, compared to their counterparts using metal contacts. The photovoltaic performance of carbon-based PSCs, however, has been progressing slowly in spite of an impressive efficiency when they were first reported. One of the major obstacles is that the hole transport materials developed for stateof-the-art Au-based PSCs are not suitable for carbon-based PSCs. Here, we develop a low-temperature,solution-processed Poly(3-hexylthiophene-2,5-diyl)(P3 HT)/graphene composite hole transport layer(HTL), that is compatible with paintable carbon-electrodes to produce state-of-the-art perovskite devices. Space-charge-limited-current measurements reveal that the as-prepared P3 HT/graphene composite exhibits outstanding charge mobility and thermal tolerance, with hole mobility increasing from8.3 × 10^-3 cm^2 V-1 s-1(as-deposited) to 1.2 × 10^-2 cm2 V^-1 s^-1(after annealing at 100°C)-two orders of magnitude larger than pure P3 HT. The improved charge transport and extraction provided by the composite HTL provides a significant efficiency improvement compared to cells with a pure P3 HT HTL. As a result, we report carbon-based solar cells with a record efficiency of 17.8%(certified by Newport);and the first perovskite cells to be certified under the stabilized testing protocol. The outstanding device stability is demonstrated by only 3% drop after storage in ambient conditions(humidity: ca. 50%) for 1680 h(nonencapsulated), and retention of ca. 89% of their original output under continuous 1-Sun illumination at room-temperature for 600 h(encapsulated) in a nitrogen environment.

Inhibition of the CDK9-cyclin T1 protein-protein interaction as a new approach against triple-negative breast cancer

Cyclin-dependent kinase 9(CDK9) activity is correlated with worse outcomes of triplenegative breast cancer(TNBC) patients. The heterodimer between CDK9 with cyclin T1 is essential for maintaining the active state of the kinase and targeting this protein-protein interaction(PPI) may offer promising avenues for selective CDK9 inhibition. Herein, we designed and generated a library of metal complexes bearing the 7-chloro-2-phenylquinoline CN ligand and tested their activity against the CDK9cyclin T1 PPI. Complex 1 bound to CDK9 via an enthalpically-driven binding mode, leading to disruption of the CDK9-cyclin T1 interaction in vitro and in cellulo. Importantly, complex 1 showed promising anti-metastatic activity against TNBC allografts in mice and was comparably active compared to cisplatin. To our knowledge, 1 is the first CDK9-cyclin T1 PPI inhibitor with anti-metastatic activity against TNBC. Complex 1 could serve as a new platform for the future design of more efficacious kinase inhibitors against cancer, including TNBC.

Lightweight epoxy-based abradable seal coating with high bonding strength

To gain high efficiency and low fuel consumption, aluminum-based abradable seal coatings had been widely used in the compressor casing of aero engines or gas turbines owing to the low elastic modulus. However, the adhesive transfer phenomenon frequently occurs when the radial rubbing generates between titanium alloy blade tips and aluminum-based coating. It tends to increase scratch force and results in blades vibration and even engine jam. To eliminate this problem, a new lightweight epoxy-based abradable seal coating with high bonding strength was developed by an effective and porosity controllable mixing process that distributes spherical pores uniformly in the continuous matrix. A lightweight coating of 63% porosity with a hardness of 33.1(HR15 Y) can be reached when the content of hollow microspheres is 31 wt.%. The coating density is 0.5 g/cm3 and the bonding strength is as high as 18 MPa.The performance of the epoxy-based coating is comprehensively better than aluminum-based coatings in five essential indices. This study is expected to provide a new technical path for obtaining high-quality abradable seal coatings to guarantee the efficient and safe operation of compressors.

Self-lubricating epoxy-based composite abradable seal coating eliminating adhesive transfer via hierarchical design

Aluminum-based composite abradable seal coatings are pivotal to improving the efficiency of aero engines or gas turbines.However,the adhesive transfer frequently occurs between metallic blade tips and aluminum-based composite coatings,resulting in engine vibration and even jam.Many past studies had tried to solve this problem by reducing coating hardness,improving lubrication,or strengthening blade tips,but all had failed.In this paper,we proposed a novel epoxy-based composite abradable seal coating,eliminating adhesive transfer by changing metal-to-metal scraping pair to metal-to-polymer scraping pair.The coating was developed via a hierarchical structure design.Large spherical pores were uniformly distributed in the continuous epoxy matrix with fine graphite dispersion.By adding 20 vol.%graphite and 50 vol.%hollow microspheres,a self-lubricating epoxy-based coating of 0.26 friction coefficient with thermal conductivity of 0.28 W/(m·K),coating HR15 Y hardness at 54.8,and bonding strength at 18.7 MPa can be reached.When the metallic blades scrape the epoxy-based composite coating,no adhesive transfer occurs.Besides,a smooth scraped surface is formed by pseudoplastic deformation.This epoxy-based composite abradable seal coating opens a new way to improve the efficiency and reliable operations of air engine compressors.

Improving WC-Co coating adhesive strength on rough substrate:Finite element modeling and experiment

The adhesive strength in a coating-substrate system is of primary importance for the coating lifetime in service.However,the underlying mechanism is not fully understood due to the complex internal structure of composite coatings.In this study,the effect of substrate roughness on the adhesive strength of WCCo coatings was investigated by experiment and simulation.Results show that the adhesive strength is significantly affected by the roughness.In the case of the Ra<2μm,the adhesive strength is approximately 35–46 MPa.When the Ra is 4μm,the adhesive strength increases to nearly 60 MPa.A finite element model was developed to correlate the roughness with adhesive strength.It is found that the predicted values are well consistent with the experimental data.In addition,with the increase of the roughness,the residual stress would be changed from concentrated state to widespread state,which decreases the critical stress to result in crack propagation.That’s why a larger roughness can cause a higher adhesive strength.This study gives understanding on the mechanism of adhesive strength affected by roughness,which contributes to the parameter optimization with better performance.

Critical scale grain size for optimal lifetime of TBCs

Thermal barrier coatings(TBCs)suffer from spalling failure resulting from the rapid growth of thermally grown oxides(TGO)on the metallic bond coat.In this study,to achieve the optimal lifetime of TBCs,a lifetime phase diagram was constructed for the entire service of TBCs.Herein,both the thermal mismatch stress during thermal cycling and the TGO growth stress during thermal exposure were considered.First,thickening behavior of the Al_(2)O_(3) scale related to grain size was investigated.Second,transverse delamination failure due to the thermal mismatch stress was analyzed.Third,vertical cracking failure related to early scale growth was explored.Finally,a critical scale grain size of~2.5μm was identified for achieving the optimal lifetime of TBCs.It was experimentally proved that vertical cracking of the Al_(2)O_(3) scale occurred during early oxidation as the scale grain size was larger than~4μm after pre-oxidation.The proposed lifetime phase diagram and critical scale grain size effect serve as novel criteria for the design of next-generation durable TBCs.

Condensation behavior of gaseous phase during transported in the near-substrate boundary layer of plasma spray-physical vapor deposition

Plasma spray-physical vapor deposition(PS-PVD)has exhibited the potential ability to prepare columnar structures for advanced thermal barrier coatings(TBCs).The coating structure is nominally affected by operating parameters,but it is controlled by the type of deposition unit actually and essentially.In order to realize the columnar structure deposited by gaseous phase units,the transition behavior of gaseous phase units to clusters must be fundamentally understood.This work investigated the transport process of gaseous phase units in the PS-PVD near-substrate boundary layer along with the condensation behavior.The Monte Carlo method was used to examine the transport process and condensation behavior of gaseous phase units under different scale boundary layers.Simulation results show that it is easier to form more numerous larger clusters at the edge of the plasma jet than at the center.Based on the understanding of the changes in deposition unit caused by the condensation of gaseous phase in the near-substrate boundary layer of PS-PVD,an outlook towards TBCs with different structures is presented.And it is in good agreement with the experimental data.

Discovery of a tetrahydroisoquinoline-based CDK9-cyclin T1 proteineprotein interaction inhibitor as an anti-proliferative and anti-migration agent against triple-negative breast cancer cells

Triple-negative breast cancer(TNBC)is a highly aggressive and metastasizing cancer that has the worst prognosis out of all breast cancer subtypes.The epithelial emesenchymal transition(EMT)and cancer stem cells(CSCs)have been proposed as important mechanisms underlying TNBC metastasis.CDK9 is highly expressed in breast cancer,including TNBC,where it promotes EMT and induces cancer cell stemness.In this study,we have identified a tetrahydroisoquinoline derivative(compound 1)as a potent and selective CDK9-cyclin T1 inhibitor via virtual screening.Interestingly,by targeting the ATP binding site,compound 1 not only inhibited CDK9 activity but also disrupted the CDK9-cyclin T1 proteineprotein interaction(PPI).Mechanistically,compound 1 reversed EMT and reduced the ratio of CSCs by blocking the CDK9-cyclin T1 interaction,leading to reduced TNBC cell proliferation and migration.To date,compound 1 is the first reported tetrahydroisoquinoline-based CDK9-cyclin T1 ATP-competitive inhibitor that also interferes with the interaction between CDK9 and cyclin T1.Compound 1 may serve as a promising scaffold for developing more selective and potent anti-TNBC agents.Our work also provides insight into the role of the CDK9-cyclin T1 PPI on EMT and CSCs and highlights the feasibility and significance of targeting CDK9 for the treatment of TNBC.

Pressure infiltration of molten aluminum for densification of environmental barrier coatings

Environmental barrier coatings(EBCs)effectively protect the ceramic matrix composites(CMCs)from harsh engine environments,especially steam and molten salts.However,open pores inevitably formed during the deposition process provide the transport channels for oxidants and corrosives,and lead to premature failure of EBCs.This research work proposed a method of pressure infiltration densification which blocked these open pores in the coatings.These results showed that it was difficult for aluminum to infiltrate spontaneously,but with the increase of external gas pressure and internal vacuum simultaneously,the molten aluminum obviously moved forward,and finally stopped infiltrating at a depth of a specific geometry.Based on the wrinkled zigzag pore model,a mathematical relationship between the critical pressure with the infiltration depth and the pore intrinsic geometry was established.The infiltration results confirmed this relationship,indicating that for a given coating,a dense thick film can be obtained by adjusting the internal and external gas pressures to drive a melt infiltration.

Achieving the high phase purity of CH_3NH_3PbI_3 film by two-step solution processable crystal engineering

To date, it is still a great challenge for highly efficient perovskite devices to realize the high quality per- ovskite films with high purity, high coverage ratio and good crystallization by two-step scalable solution method. In this study, a series PbI2 films with tunable micro-architecture of Pbl2 crystals are prepared via solution processable crystal engineering. The perovskite film, prepared by optimized pit spacing in gas pumped PbI2 film at 1000 Pa, shows the highest film quality, including no residual Pbl2 phase, compact morphology, and improved photoluminescence intensity. A transformation kinetics shows that the pit spacing strongly influences both the mass transfer and the sequential intercalation reaction between CH3NH31 and PbI2 crystals, which ultimately determines the full reaction state of the perovskite film. The perovskite solar cells assembled by the perovskite film show both high power-conversion efficiency and good reproducibility of photovoltaic performance due to the restrained charge recombination arising from the high quality perovskite film.