Analysis of environmental selection pressure of superoxide dismutase in deep-sea sea cucumber

Manganese superoxide dismutase(MnSOD)is an antioxidant that exists in mitochondria and can effectively remove superoxide anions in mitochondria.In a dark,high-pressure,and low-temperature deep-sea environment,MnSOD is essential for the survival of sea cucumbers.Six MnSODs were identified from the transcriptomes of deep and shallow-sea sea cucumbers.To explore their environmental adaptation mechanism,we conducted environmental selection pressure analysis through the branching site model of PAML software.We obtained night positive selection sites,and two of them were significant(97F→H,134K→V):97F→H located in a highly conservative characteristic sequence,and its polarity c hange might have a great impact on the function of MnSOD;134K→V had a change in piezophilic a bility,which might help MnSOD adapt to the environment of high hydrostatic pressure in the deepsea.To further study the effect of these two positive selection sites on MnSOD,we predicted the point mutations of F97H and K134V on shallow-sea sea cucumber by using MAESTROweb and PyMOL.Results show that 97F→H,134K→V might improve MnSOD’s efficiency of scavenging superoxide a nion and its ability to resist high hydrostatic pressure by moderately reducing its stability.The above results indicated that MnSODs of deep-sea sea cucumber adapted to deep-sea environments through their amino acid changes in polarity,piezophilic behavior,and local stability.This study revealed the correlation between MnSOD and extreme environment,and will help improve our understanding of the organism’s adaptation mechanisms in deep sea.

Selective laser melting of GH3536 superalloy:microstructure,mechanical properties,and hydrocyclone manufacturing

The effect of scanning strategy on the microstructure and properties of GH3536 Ni-based superalloy prepared by Laser Powder Bed Fusion was investigated,for the purpose of building high quality hydrocyclone part.The results show that the strength of Z67°(a zone with 67°hatch angle strategy)specimen is the highest among the four scanning strategies(0°,67°,90°and Z67°),with yield strength and tensile strength of 681 MPa and 837 MPa,respectively.Selective orientation of crystals occurs during the forming process because the longitudinal section of the specimen exhibits a high texture strength in(001).As the stretching proceeds,the plastic deformation mechanism of the specimen gradually changes from slip to twin-dominated,a substantial amount of twinning is observed in the region where the deformation of the specimen reaches 80%.The additive manufacturing simulation suite:Ansys Additive is used to simulate the stress and deformation of the part during the process,and the displacement results are consistent with the experimental phenomena.According to the simulation results,the structure design is optimized and the surface quality of the part is improved.The results show that the support of the part is more reasonable when the overhang angle is 45°.

磁性可循环高熵金属氧化物催化剂用于活化氧气催化氧化脱硫

燃油中的含硫化合物燃烧会导致酸雨、雾霾等环境问题,因此需要降低燃油中硫化物浓度.但是,目前工业上采用的加氢脱硫(HDS)技术在脱除芳香硫化物时需要更高的温度、压力和氢耗,不利于碳减排(生产1吨H2排放10–20吨CO_(2)),因此亟需开发非HDS工艺.在各种非HDS技术中,以O_(2)为氧化剂的氧化脱硫(ODS)技术由于具有对芳香族硫化物脱除性能高、成本低、反应条件温和等优点,而受到广泛关注.在ODS过程中,催化剂的设计是关键之一.研究发现,金属氧化物具有较好的活化O_(2)性能,但是传统金属氧化物存在活性位点有限、分离回收较难等不足.近年来,人们发现,高熵金属氧化物在以O_(2)为氧化剂的催化氧化反应中表现出较好的催化性能,但如何进一步提升其循环使用性能,是目前高熵金属氧化物在ODS中应用所面临的挑战.为解决上述问题,本文通过组分设计在高熵金属氧化物催化剂中引入高催化活性组分和磁性元素,再采用机械化学球磨辅助高温煅烧策略,构筑了一类新型磁性高熵金属氧化物催化剂(CoCrFeMnNiO_(x),HEMO),并用于活化O_(2)催化氧化脱除燃油中芳香族硫化物.实验发现,900℃煅烧制得的HEMO-900催化剂性能最优.催化剂的结构表征结果表明,通过球磨辅助策略能够降低高熵结构的形成温度.进一步研究表明,高熵结构不仅能够提升催化活性组分的分散度,而且有助于活性组分的电荷调控,从而显著增强了HEMO-900对O_(2)分子的活化能力.将所制备的HEMO-900催化剂用于以O_(2)为氧化剂的燃油氧化脱硫体系中,能够获得较好的脱硫性能,在最优条件下能够获得96.9%的脱硫率(硫化物浓度降低至0.001%以下).此外,HEMO-900催化剂能够高效氧化脱除燃油中不同种类芳香族硫化合物,拓宽了其在不同类型燃油深度脱硫中的应用.进一步分析发现,HEMO-900催化剂可以将燃油中二苯并噻吩定向氧化为二苯并噻吩砜.同时,HEMO-900催化剂对真实油品中的硫化物也表现出较好的脱除性能.此外,HEMO-900催化剂还有较好的磁性循环使用性能:通过外加磁场,可以快速将HEMO-900催化剂与燃油相分离,该性能使得催化剂能够在连续反应过程中被高效回收和重复利用.本研究中,HEMO-900催化剂在5次循环使用后,其ODS活性仍达到91.1%综上所述,本文通过机械化学球磨辅助高温煅烧法成功合成了一种可磁性回收的高熵金属氧化物催化剂,实验发现了机械球磨辅助能够显著降低高熵结构的形成温度.设计制得的催化剂兼具较好的活化O_(2)催化燃油氧化脱硫性能和可磁性分离回收的特点.通过设计该类可磁性分离的高熵金属氧化物催化剂,不仅为实现温和条件下燃油深度脱硫提供新的选择,而且为其他多相催化氧化反应催化剂设计提供了新思路.

Circ RNA and ferroptosis in human disease:Insights for new treatments

Circular RNA(circ RNA),classified as a type of non-coding RNA,has gained significant attention in the field of biology due to its distinctive ring structure and functional properties.Recent research has provided evidence that specific circ RNAs have the ability to modulate disease progression through diverse mechanisms,one of which is by regulating cellular ferroptosis.Ferroptosis is a form of regulated cell death that is driven by iron dependency and lipid peroxidation,and extensive investigations have revealed a relationship between ferroptosis and disease development.In addition to evidence that both circ RNAs and ferroptosis exert critical roles in disease progression,circ RNAs have also been shown to actively mediate the process of ferroptosis.The relationship between circ RNAs and ferroptosis therefore influences disease progression and offers novel targets for disease treatment.By directly or indirectly modulating the expression of circ RNAs that regulate the expression of ferroptosisrelated proteins,it may be possible to impact disease progression by promoting or inhibiting ferroptosis.Current research indicates such approaches may hold significant value in a wide variety of common diseases across physiological systems.This review comprehensively summarizes the findings of recent studies investigating the roles of circ RNAs in the regulation of ferroptosis in various diseases.

Prediction of curved oil–water interface in horizontal pipes using modified model with dynamic contact angle

In this study,interface shapes of horizontal oil–water two-phase flow are predicted by using Young-Laplace equation model and minimum energy model.Meanwhile,the interface shapes of horizontal oil–water twophase flow in a 20 mm inner diameter pipe are measured by a novel conductance parallel-wire array probe(CPAP).It is found that,for flow conditions with low water holdup,there is a large deviation between the model-predicted interface shape and the experimentally measured one.Since the variation of pipe wetting characteristics in the process of fluid flow can lead to the changes of the contact angle between the fluid and the pipe wall,the models mentioned above are modified by considering dynamic contact angle.The results indicate that the interface shapes predicted by the modified models present a good consistence with the ones measured by CPAP.

Positive selection analysis reveals the deep-sea adaptation of a hadal sea cucumber ( Paelopatides sp.) to the Mariana Trench

The Mariana Trench,the deepest trench on the earth,is ideal for deep-sea adaptation research due to its unique characters,such as the highest hydrostatic pressure on the Earth,constant ice-cold temperature,and eternal darkness.In this study,tissues of a the hadal holothurian(Paelopatides sp.)were fi xed with RNA later in situ at~6501-m depth in the Mariana Trench,which,to our knowledge,is the deepest in-situ fi xed animal sample.A high-quality transcript was obtained by de-novo transcriptome assembly.A maximum likelihood tree was constructed based on the single copy orthologs across nine species with their available omics data.To investigate deep-sea adaptation,113 positively selected genes(PSGs)were identifi ed in Paelopatides sp.Some PSGs such as microphthalmia-associated transcription factor(MITF)may contribute to the distinct phenotype of Paelopatides sp.,including its translucent white body and degenerated ossicles.At least eight PSGs(transcription factor 7-like 2[TCF7L2],ETS-related transcription factor Elf-2-like[ELF2],PERQ amino acid-rich with GYF domain-containing protein[GIGYF],cytochrome c oxidase subunit 7a,[COX7A],type I thyroxine 5′-deiodinase[DIO1],translation factor GUF1[GUF1],SWI/SNF related-matrix-associated actin-dependent regulator of chromatin subfamily C and subfamily E,member 1[SMARCC]and[SMARCE1])might be related to cold adaptation.In addition,at least nine PSGs(cell cycle checkpoint control protein[RAD9A],replication factor A3[RPA3],DNA-directed RNA polymerases I/II/III subunit RPABC1[POLR2E],putative TAR DNA-binding protein 43 isoform X2[TARDBP],ribonucleoside-diphosphate reductase subunit M1[RRM1],putative serine/threonine-protein kinase[SMG1],transcriptional regulator[ATRX],alkylated DNA repair protein alkB homolog 6[ALKBH6],and PLAC8 motif-containing protein[PLAC8])may facilitate the repair of DNA damage induced by the high hydrostatic pressure,coldness,and high concentration of cadmium in the upper Mariana Trench.

Mechanical Properties and Microstructure of the Shear Band Formed at Cryogenic Temperature in the NiCrFe Medium‑Entropy Alloy

There are nanotwins in the shear band formed in a moment(about 10^(−5)s)in some NiCrFe-based medium-entropy alloys(MEAs),and these shear bands can be recognized as a special kind of materials due to their high strength and good plasticity.In this study,the single shear band of the NiCrFe MEA was prepared at 77 K.A series of characterizations were carried out to analyze the microstructures in the shear band.The strength of the shear band was investigated by the split Hopkinson pressure bar and in-situ compression.The micropillar in the shear band containing nanotwins exhibits excellent strengthplasticity synergy.The compressive yield strength of the shear band measured by in-situ compression is 175%higher than that of the matrix,reaching 1405 MPa,with the fracture strain exceeding 0.5.The strengthening mechanism of the shear band was revealed by the combination of the experimental results and molecular dynamics simulation.The synergistic effect of multiple strengthening mechanisms enhances the strength of the NiCrFe MEA containing nanotwins,in which the grain boundary strengthening of the ultrafine equiaxed grains and the dynamic Hall–Petch effect of the nanotwins dominate.In addition,the good plasticity of the shear band is ascribed to the stress concentration reduction of the twin boundaries of nanotwins and the activation of multiple slip systems due to the randomly oriented nanotwins.These findings provide theoretical guidance for the design of nanotwinned MEAs to realize excellent strength-plasticity synergy for structural materials.

An overview of the switching parameter variation of RRAM

Resistive random access memory(RRAM) has been considered as one of the most promising candidates for next-generation nonvolatile memory, due to its advantages of simple device structure, excellent scalability, fast operation speed and low power consumption. Deeply understanding the physical mechanism and effectively controlling the statistical variation of switching parameters are the basis of fostering RRAM into commercial application. In this paper, based on the deep understanding on the mechanism of the formation and rupture of conductive filament, we summarize the methods of analyzing and modeling the statistics of switching parameters such as SET/RESET voltage, current, speed or time. Then, we analyze the distributions of switching parameters and the influencing factors. Additionally, we also sum up the analytical model of resistive switching statistics composed of the cell-based percolation model and SET/RESET switching dynamics. The results of the model can successfully explain the experimental distributions of switching parameters of the Ni O- and Hf O2-based RRAM devices. The model also provides theoretical guide on how to improve the uniformity and reliability such as disturb immunity. Finally, some experimental approaches to improve the uniformity of switching parameters are discussed.