Service Life Design for Concrete Engineering in Marine Environments of Northern China Based on a Modified Theoretical Model of Chloride Diffusion and Large Datasets of Ocean Parameters

In this study,through experimental research and an investigation on large datasets of the durability parameters in ocean engineering,the values,ranges,and types of distribution of the durability parameters employed for the durability design in ocean engineering in northern China were confirmed.Based on a modified theoretical model of chloride diffusion and the reliability theory,the service lives of concrete structures exposed to the splash,tidal,and underwater zones were calculated.Mixed concrete proportions meeting the requirement of a service life of 100 or 120 years were designed,and a cover thickness requirement was proposed.In addition,the effects of the different time-varying relationships of the boundary condition(Cs)and diffusion coefficient(Df)on the service life were compared;the results showed that the time-varying relationships used in this study(i.e.,Cscontinuously increased and then remained stable,and Dfcontinuously decreased and then remained stable)were beneficial for the durability design of concrete structures in marine environment.

溶瘤病毒在乳腺癌治疗中的研究进展

乳腺癌是女性最常见的恶性肿瘤之一,尽管现有治疗手段对乳腺癌的治疗效果已有较大改进,但对晚期及三阴性乳腺癌仍有局限性,因此需要探索新的治疗方法。溶瘤病毒(oncolytic viruses,OVs)疗法是肿瘤免疫疗法的一种,OVs通过靶向作用可特异性地杀伤肿瘤细胞、抑制血管生成、调节肿瘤微环境、促进抗肿瘤免疫。目前,乳腺癌治疗中使用的OVs种类较多,其有效性及安全性尚可,在联合免疫治疗时有协同促进作用。本文将就OVs在乳腺癌治疗中的主要研究进展进行综述。

Mesoscopic Modeling Approach and Application for Steel Fiber Reinforced Concrete under Dynamic Loading:A Review

Steel fiber reinforced concrete(SFRC)has drawn extensive attention in recent years for its superior mechanical response to dynamic and impact loadings.Based on the existing test results,the highstrength steel fibers embedded in a concrete matrix usually play a strong bridging effect to enhance the bonding force between fiber and the matrix,and directly contribute to the improvement of the post-cracking behavior and residual strength of SFRC.To gain a better understanding of the action behavior of steel fibers in matrix and further capture the failure mechanism of SFRC under dynamic loads,the mesoscopic modeling approach that assumes SFRC to be composed of different mesoscale phases(i.e.,steel fibers,coarse aggregates,mortar matrix,and interfacial transition zone(ITZ))has been widely employed to simulate the dynamic responses of SFRC material and structural members.This paper presents a comprehensive review of the state-of-the-art mesoscopic models and simulations for SFRC under dynamic loading.Generation approaches for the SFRC mesoscale model in the simulation works,including steel fiber,coarse aggregate,and the ITZ between them,are reviewed and compared systematically.The material models for different phases and the interaction relationship between fiber and concrete matrix are summarized comprehensively.Additionally,some example applications for SFRC under dynamic loads(i.e.,compression,tension,and contact blast)simulated using the general mesoscale models are given.Finally,some critical analysis on the current shortcomings of the mesoscale modeling of SFRC is highlighted,which is of great significance for the future investigation and development of SFRC.

Three-Dimensional Mesoscopic Investigation on the Impact of Specimen Geometry and Bearing Strip Size on the Splitting-Tensile Properties of Coral Aggregate Concrete

The use of coral aggregate concrete(CAC)as a novel construction material has attracted significant attention for the construction of reef engineering structures.To investigate the static splitting-tensile behaviors of CAC under the influence of two factors,namely specimen geometry and bearing strip size,a three-dimensional(3D)mesoscale modeling approach with consideration for aggregate randomness in shape and distribution was adopted in this study.We established 12 different specimen models with two specimen shapes(i.e.,a cube with an edge length of 150 mm and a cylinder with dimensions ofφ150 mm×300 mm)and six strip widths(i.e.,6,9,12,15,18,and 20 mm)for calculation.The effects of specimen geometry and strip width on the splitting-tensile properties of CAC,such as failure processes,final failure patterns,and splitting-tensile strength(fst),are analyzed and discussed systematically.The results indicate the high reliability of the developed mesoscale modeling approach and reveal the optimal computational parameters for simulating and predicting the splitting-tensile properties of CAC.The fstvalues of CAC are associated with both the specimen geometry and width of the bearing strip.The fstvalues of the cube model are slightly higher than those of the cylinder model for the same bearing strip size,representing geometry effects that can be explained by differences in fracture area.Additionally,the fstvalue of CAC gradually increases with the relative width of the bearing strip ranging from 0.04 to 0.13.Based on the elastic solution theory,the variation area of CAC fstvalues with the relative width of the bearing strip was determined preliminarily,which has great significance for studying the tensile performance of CAC.

Access to High-Molecular-Weight Polyethylenes through High Temperature Ethylene Polymerization Catalysed by Ethylene-Bridged ansa-(3-R-Cyclopentadienyl)(Fluorenyl) Zirconocene Complexes

A series of C1-symmetric ethylene-bridged ansa-(3-R-cyclopentadienyl)(fluorenyl) metallocene complexes(Zr: 1-5;Hf: 6) have been synthesized, characterized and investigated as catalyst precursors for the high temperature ethylene polymerization. Using methylaluminoxane(MAO) as the cocatalyst, zirconium complexes 1-5 bearing a bulky substituent on the 3-position of the cyclopendienyl ring showed high catalytic activities up to 1.48×10^(7) g PE·mol_(Zr)^(-1)·h^(-1) toward the polymerization of ethylene and afforded polyethylenes with high molecular weights(1.49×10^(5)-6.31×10^(5) g/mol), meanwhile exhibting great thermal stability at high temperatures up to 120 ℃ together with a long catalytic life time up to 2 h. By adopting low Al/Zr ratios, such as 125, polyethylenes with ultra high molecular weights up to 2.86×106 g/mol were obtained. It is worthy of noting that zirconium complexes 1-4 bearing a substituent with an aryl pendant showed temperature-dependent activities, which increased rapidly with the increase of polymerization temperature, thus weak interaction of the pendent aryl group with the cationic active center is proposed to account for the very low activities displayed at low temperatures. In contrast to zirconocene complexes 1-5, hafnocene complex 6 only displayed very low catalytic activities toward the polymerization of ethylene and afforded polyethylenes with molecular weights ten times smaller than those obtained by zirconocene complexes 1-5. Zirconocene complexes 1-5 were also able to catalyse the polymerization of propylene at high temperatures, but only afforded waxes with low molecular weights.

Tiller Bud Formation Regulators MOC1 and MOC3 Cooperatively Promote Tiller Bud Outgrowth by Activating F0N1 Expression in Rice

Tillering in rice is one of the most important agronomic traits.Rice tiller development can be divided into two main processes: the formation of the axillary bud and its subsequent outgrowth.Several genes critical for bud formation in rice have been identified by genetic studies;however,their molecular functions and relationships are still largely unknown.Here,we report that MONOCULM 1 (MOC1) and MONOCULM 3/ TILLERS ABSENT 1/STERILE AND REDUCED TILLERING 1 (MOC3/TAB1/SRT1),two vital regulators for tiller formation in rice,physically interact to regulate tiller bud outgrowth through upregulating the expression of FLORAL ORGAN NUMBER 1 (FON1),the homolog of CLAVATA1 in rice.We found that M0C3 is able to directly bind the promoter ofFONI and subsequently activate FON1 expression.MOC1 functions as a coactivator of MOC3,whereas it could not directly bind the FON1 promoter,and further activated FON1 expression in the presence of MOC3.Accordingly,FON1 is highly expressed at axillary meristems and shows remarkably decreased expression levels in mod and moc3 mutants.Loss-of-function mutants of FON1 exhibit normal bud formation but defective bud outgrowth and reduced tiller number.Collectively,these results shed light on a joint transcriptional regulatory mechanim by MOC1 and MOC3,and establish a new framework for the control of tiller bud formation and outgrowth.

Regulation of mitochondrial NAD pool via NAD^+ transporter 2 is essential for matrix NADH homeostasis and ROS production in Arabidopsis

Reactive oxygen species(ROS) play a crucial role in numerous biological processes in plants, including development, responses to environmental stimuli, and programmed cell death(PCD). Deficiency in MOSAIC DEATH 1(MOD1), a plastid-localized enoyl-ACP reductase essential for de novo fatty acid biosynthesis in Arabidopsis thaliana, leads to the increased malate export from chloroplasts to mitochondria, and the subsequent accumulation of mitochondria-generated ROS and PCD. In this study, we report the identification and characterization of a mod1 suppressor, som592. SOM592 encodes mitochondrion-localized NAD^+ transporter 2(NDT2). We show that the mitochondrial NAD pool is elevated in the mod1 mutant. The som592 mutation fully suppressed mitochondrial NADH hyper-accumulation, ROS production, and PCD in the mod1 mutant, indicating a causal relationship between mitochondrial NAD accumulation and ROS/PCD phenotypes. We also show that in wild-type plants, the mitochondrial NAD+uptake is involved in the regulation of ROS production in response to continuous photoperiod. Elevation of the alternative respiration pathway can suppress ROS accumulation and PCD in mod1, but leads to growth restriction. These findings uncover a regulatory mechanism for mitochondrial ROS production via NADH homeostasis in Arabidopsis thaliana that is likely important for growth regulation in response to altered photoperiod.

结核性腕屈肌腱鞘炎伴米粒体MRI表现及病理分型

回顾性分析2015年6月至2022年2月贵州省人民医院15例经手术病理确诊为结核性腕屈肌腱鞘炎伴米粒体的临床、影像及病理资料。15例X线片示腕掌部肿胀, CT示腕掌部"葫芦"形低密度肿块, MRI示腱鞘滑膜炎, 大量米粒体形成, 与滑液信号比较, 米粒体在各序列均呈低信号, 呈"铺路石"或"蜂窝"样, 3例伴结核性腕关节炎。7例Ⅰ型米粒体为结核性肉芽肿, 8例Ⅱ型米粒体为嗜酸性蛋白。"铺路石"或"蜂窝"征是滑膜炎伴米粒体形成的重要影像征象。

Ethylene-bridged Indenyl-fluorenyl Metallocene Complexes for Efficient Preparation of Allyl-terminated Propylene Oligomers and Polymers via Selective β-Methyl Transfer

Four C_1-symmetric ansa-metallocene complexes, C_2H_4(Ind)(2,7-~tBu_2-Flu)ZrCl_2(4), C_2H_4(3-Bn-Ind)(2,7-~tBu_2-Flu)ZrCl_2(5),C_2H_4(3-Bn-Ind)(3,6-~tBu_2-Flu)ZrCl_2(6), and C_2H_4(3-Bn-Ind)(2,7-~tBu_2-Flu)HfCl_2(7), were synthesized and characterized. The structures of complexes 4, 5, and 7 were further determined via X-ray diffraction studies. Upon activation with modified methylaluminoxane(MMAO) or Al^iBu_3/[Ph_3C][B(C_6F_5)_4](TIBA/TrB), most of these complexes showed high efficiency in catalyzing propylene oligomerization/polymerization to afford products dominantly with allyl terminals via selective β-methyl transfer(β-Me transfer). The introduction of 3-benzyl group on the indenyl ring of the complexes was found to be crucial in enabling highly selective β-Me transfer during the polymerization process, leading to selectivities up to 89% obtained by zirconocene complexes 5 and 6, and up to 91% obtained by hafnocene complex 7. Detailed chain-end analysis by ~1H-NMR, ^(13)C-NMR, and MALDI-TOF mass spectroscopy revealed that the allyl chain-ends of the polymeric products resulted from a selective β-Me transfer process after two successively primary insertions of the monomer. Further studies concerning the dependence of chain release selectivity as well as the molecular weight of products on monomer concentration suggested that both β-Me transfer(major) and β-hydrogen transfer(β-H transfer)(minor) mediated by 5/MMAO and 6/MMAO systems may mainly operate in a bimolecular pathway.

Seasonal dynamics of water bloom-forming Microcystis morphospecies and the associated extracellular microcystin concentrations in large,shallow,eutrophic Dianchi Lake

The increasing occurrence of Microcystis blooms is of great concern to public health and ecosystem due to the potential hepatotoxic microcystins （MCs） produced by these colonial cyanobacteria. In order to interpret the relationships between variations of Microcyst/s morphospedes and extracellular MC concentrations, the seasonal dynamics of phytoplankton community composition, MC concentrations, and environmental parameters were monitored monthly from August, 2009 to July, 2010. The results indicated that Microcystis dominated total phytoplankton abundance from May to December （96%--99% of total biovolume）, with toxic Microcystis viridis and non-toxic Microcystis wesenbergii dominating after July （constituting 65%- 95% of the Microcystis population）, followed by M. viridis as the sole dominant species from November to January （49%--93%）. Correlation analysis revealed that water temperature and nutrient were the most important variables accounting for the occurrence ofM. wesenbergii, while the dominance ofM. viridis was related with nitrite and nitrate. The relatively low content of MCs was explained by the association with a large proportion of M. viriclis and M. wesenbergii, small colony size of Microcystis populations, and low water temperature, pH and dissolved oxygen. The extracellular MC （mean of 0.5 ± 0.2 μg/L） of water samples analyzed by enzyme-linked immunosorbent assay （ELISA） demonstrated the low concentrations of MC in Dianchi Lake which implied the low potential risk for human health in the basin. The survey provides the first whole lake study of the occurrence and seasonal variability of Microcyst/s population and

A Profile of Native Integration Sites Used by φC31 Integrase in the Bovine Genome

The Streptomyces phage φC31 integrase can efficiently target attB-bearing transgenes to endogenous pseudo attP sites within mammalian genomes. To better understand the activity of φC31 integrase in the bovine genome, DNA sequences of 44 integration events were analyzed, and 32 pseudo attP sites were identified. The majority of these sites share a sequence motif that contains inverted repeats and has similarities to wild-type attP site. Genomic DNA flanking these sites typically contained repetitive sequence elements, such as short and long interspersed repetitive elements. These sequence features indicate that DNA sequence recognition plays an important role in guiding φC31-mediated site-specific integration. In addition, BF27 integration hotspot sites were identified in the bovine genome, which accounted for 13.6% of all isolated integration events and mapped to an intron of the deleted in liver cancer 1 （DLC1） gene. Also we found that the pseudo attP sites in the bovine genome had other features in common with those in the human genome. This study represents the first time that the sequence features of pseudo attP sites specific integrase system has great potential for applied modifications in the bovine genome were analyzed. We conclude that this site- of the bovine genome.

Influence of steel corrosion on axial and eccentric compression behavior of coral aggregate concrete column

To study the behavior of coral aggregate concrete(CAC)column under axial and eccentric compression,the compression behavior of CAC column with different types of steel and initial eccentricity(ei)were tested,and the deformation behavior and ultimate bearing capacity(Nu)were studied.The results showed that as the ei increases,the Nu of CAC column decreases nonlinearly.Besides,the steel corrosion in CAC column is severe,which reduces the steel section and steel strength,and decreases the Nu of CAC column.The durability of CAC structures can be improved by using new organic coated steel.Considering the influence of steel corrosion and interfacial bond deterioration,the calculation models of Nu under axial and eccentric compression were presented.

Binuclear Aluminum Complexes Supported by Linked Bis(β-diketiminate) Ligands for Ring-Opening Polymerization of Cyclic Esters

Binuclear aluminum alkyl complexes 2a–4g supported by linked bis（β-diketiminate） ligands were synthesized via the reaction of AlEt3 or AlMe3 and the corresponding proligand in a 2：1 molar ratio with moderate yields. The isolated complexes were well-characterized by ^1H-NMR, ^13C-NMR and elemental analysis. The binuclear nature of aluminum complex 2b was further confirmed by an X-ray diffraction study. All complexes 2a–4g could efficiently initiate the ring-opening polymerization（ROP） of ε-caprolactone in toluene. The substituents at the aromatic rings and the linker unit in the auxiliary ligands exerted significant influence on the catalytic behavior of the investigated aluminum complexes. Complex 4g（R^1 = R^2 = Cl） containing propylenyl bridging unit exhibited the highest catalytic activity among these complexes, which might be attributed to the increased electrophilicity of the metal center as well as more opened coordination sphere. The molecular weights of obtained poly（ε-caprolactone）s deviating considerably from the theoretical values indicated that the ROP of ε-caprolactone by complexes 2a–4g was not well-controlled, which was also judged from the broad molecular weight distributions（MWD = 1.47-2.47） of produced poly（ε-caprolactone）s. These complexes proved to be inactive toward the polymerization of rac-lactide alone. In the presence of alcohol the polymerization occurred, which was actually initiated by the decomposition species of the aluminum complex upon the treatment with isopropanol.