Norsesquiterpenoids from the leaves of Croton tiglium

Two new compounds,badounoids A(1)and B(2),together with 13 known norsesquiterpenes,were isolated from the leaves of Croton tiglium L.The structures of the new compounds were established by means of spectroscopic methods.The absolute configuration of badounoid B was determined by single-crystal X-ray diffraction analysis.All the known compounds were isolated from Croton plants for the first time which added a new chemical facet for this genus.The selected compounds were evaluated for their cytostatic activity against several cancer cell lines.None of them was found to be active.

Experimental study on Ti+Nb bearing ultra-low carbon bake hardening sheet steel hot-rolled in the ferrite region

A Ti＋Nb bearing ultra-low carbon bake hardening sheet steel hot-rolled in the conventional austenite region and in the ferrite region with lubrication was experimentally studied. Subsequent cold rolling and continuous annealing processes were also conducted. The results show that microstructures of ultra-low carbon bake hardening hot strips at room temperature are basically irregular polygonal ferrites. The yield strength, ultimate tensile strength, n value, and r value of the No.2 specimen hot-rolled in the ferrite region with lubrication are 243 MPa, 364 MPa, 0.29, and 1.74, respectively, which are similar to those of the No.1 specimen hot-roiled in the conventional austenite region. The elongation rate and bake hardening value of No.2 specimen are 51% and 49.4 MPa, respectively, which are greater than those of No. 1 specimen. The No.2 specimen hot-rolled in the ferrite region with lubrication exhibits good mechanical properties and relatively excellent baking hardening performance. Therefore, the hot rolling experiment of Ti＋Nb bearing ultra-low carbon bake hardening steel in the ferrite region with lubrication is feasible and can be considered in the future industrial trial production.

Modulation of Self-healing of Polyion Complex Hydrogel by Ion-specific Effects

我们准备了 polyion 建筑群(照片) hydrogel 由组成 poly (3-(methacryloylamino ) propyl-trimethylamonium 氯化物) 并且 poly (钠 p-styrenesulfonate ) 经由一个二拍子的圆舞聚合过程的聚合电解质并且在 PIC hydrogel 的 self-healing 上调查了特定的离子效果。我们的学习证明 PIC hydrogel 的机械性质强烈依赖于在 hydrogel 做的离子的类型。离子特定的效果能被用来调制 PIC hydrogel 的 self-healing 效率。当做的阴离子从 kosmotrops 改变到 chaotropes， PIC hydrogel 的 self-healing 效率增加。一个更多的 chaotropic 阴离子有一个更强壮的能力打破在 hydrogel 以内形成的离子的契约，导致在愈合期间的更高的效率。

Neonatal activation of Pxr results in persistent altered expression of DMEs in adult mice

OBJECTIVE To demonstrate the long-or short-term impacts of neonatal Pxr(pregnane X receptor) agonists exposureon DMEs(drug metabolism enzymes) expression in adulthood.METHODS C57 BL/6 mice(day 5,postnatal) were injected with different doses(0,50,100,150,200 mg·kg^(-1) ·d^(-1),constitutive 4 d) of PCN(pregnenolone-16 a-carbonitrile).Mice at different ages(day 5,10,15,25,postna.tal) were administrated with 200 mg·kg^(-1)·d^(-1) PCN in constitutive 4 d.All mice were sacrificed at day 60 after birth.Liver samples were collected for detecting the expression of Pxr target genes.RESULTS Compared with vehicle group,the significant inductions of Cyp2 b10,Cyp3a11 and Pxrwere observed in high dose groups(150,200 mg·kg^(-1) ·d^(-1),5-8 d after birth) both in male and female mice(n=4-9/group,P<0.05).Furthermore,high dose groups(200 mg·kg^(-1)·d^(-1),5-8 d after birth) were found to have higher mRNA expression levels of Cyp2a4,Ugt1a1,Abcc4,and Oatpla4 in female mice,while Papss2 in male mice compared with vehicle groups(n= 4-9/group,P<0.05).Interestingly,a decreased mRNA expression of Sult2a1 was identified in 200(5-8 d) groups(n=4-9/group,P<0.05).Consistent with these results,the protein expression of Cyp3a11 was only increased in 200(5-8 d) groups compared with the vehicle groups(n=3/group,P<0.05).Importantly,the persistent impacts on DMEs only occurred in day 5 and day 25 treatment groups,not day 10 and day 15 groups(n=4/group).CONCLUSION Neonatal Pxr activation has a long-term effect on the expression of DMEs in C57BL/6 mice.Dose and treatment exposure time are two key factors involved in this permanent alteration procedure.

长链非编码RNA在眼部疾病的研究进展

长链非编码RNA(lncRNA)被定义为长度超过200个核苷酸并从人类基因组转录而未翻译(非编码)的RNA。随着人类基因组测序及图谱绘制的顺利完成,在随后启动的ENCODE研究中发现,约75%的基因组序列可以被转录成RNA,而其中大部分转录产物为非编码RNA。近年研究发现,lncRNA广泛参与生物个体的发育、细胞增殖、细胞分化等体内多种重要的生理及病理过程,如细胞周期调控、细胞代谢、细胞凋亡、诱导多能干细胞的重编程及表观遗传调控等生物学功能,而差异性表达对人类各种疾病的发生起着重要的作用,如恶性肿瘤、炎症及免疫性疾病等。研究表明lncRNA与眼科疾病的发病机制也密切相关,本文对近年来关于lncRNA的异常表达与眼部疾病的研究现状做一综述。

Impacts of maternal LPS exposure on proinflammatory cytokines and DMEs expression in mouse offspring

OBJECTIVE To explore the effects of perinatal inflammation on the expression of proin.flammatory cytokines and DMEs(drug metabolism enzymes) in offspring mice.METHODS C57 BL/6 maternal mice were administrated with single dose 100 μg·kg^(-1) LPS(lipopolysaccharide) or saline(vehicle)during gestation(day 10 after fertilization).Offspring mice were sacrificed at 30 d after birth and liver samples were collected.Real-time PCR was adopted to test the mRNA expression of proinflammatory cytokines(Nrlp3 and IL-1β),nuclear receptors(Pxr and Car),and DMEs(Cyp3a11,2b10,1a2,and Ugt1a1).RESULTS Gender different expression of candidate genes was observed.The expression of Car,in the maternal injection of LPS groups,was significantly decreased in both female and male offspring(n=3-8/group,P<0.01).Concomitantly,a significantly lower expression of Cyp3a11 was found in both female and male offspring(P<0.01,P<0.05,respectively).Furthermore,the expression of Ugt1a1 was reduced in male offspring following maternal administration of LPS(P<0.01).In male offspring,Nrlp3 expression was specially decreased(P<0.05).Interestingly,there was an approximately 66% reduction in mRNA level of Cyp1a2 in female offspring(P<0.01),while in male offspring Cyp1a2 expression showed an increased trend(P>0.05) compared with vehicle group.The expression of Pxr,Cyp2b10,and IL-1β was no difference between LPS treatment group and vehicle group(P>0.05).CONCLUSION Maternal LPS administration affects the expression of proinflammatory cytokines,nuclear receptors and DMEs in mouse offspring.

Specific Ion Effects on the Enzymatic Degradation of Polyester Films

Soil environment on earth contains a variety of ions,which are expected to play a vital role in the biodegradation of plastics discarded in the environment.In this work,poly(butyleneadipate-co-terephthalate)(PBAT)is employed as a model biodegradable plastic to study the specific ion effects on the enzymatic degradation of polyester plastics.The results show that the specific ion effects on the enzymatic degradation rate of the PBAT films and on the catalytic rate constant for the enzymatic hydrolysis of the ester bonds are strongly dependent on temperature and ionic strength.Both the enzymatic degradation rate and catalytic rate constant decrease following the trends Na^(+)>K^(+)>Ca^(2+)and Cl^(-)>SO_(4)^(2-)>NO_(3)^(-)for cations and anions,respectively,indicating that the ion-specific enzymatic degradation of the PBAT films is closely correlated with the specific ion effects on enzymatic hydrolysis of the ester bonds.Our study shows that the specific ion effects on the enzyme activity can be understood by taking into account the ion-specific cation-anion interaction,ionic dispersion force,salting-out effect and salting-in effect.This study of specific ion effects on the enzymatic hydrolysis of the ester bonds and the resultant enzymatic degradation of the PBAT films would offer us a new clue to develop new biodegradable,environmentally friendly synthetic plastics.

Numerical simulation of flow characteristics of side-bottom combined blowing in iron bath reactor

A numerical model of an iron bath smelting reduction furnace with side-bottom combined blowing was established to study the influence of blowing arrangements on the stirring effect of the molten pool,and the accuracy of numerical simulation was verified by water model experiment.By comparing the flow field of molten pool with single nozzle,double nozzles(symmetrical and asymmetrical),and four nozzles(symmetrical and asymmetrical),the proportion of dead zone,average turbulent kinetic energy,and mixing time,the results show that asymmetrical bottom blowing is better than symmetrical bottom blowing,and the effect of double nozzles bottom blowing was better than that of four nozzles bottom blowing.The mixing effect is the worst under the condition of single nozzle.When the bottom blowing is asymmetrical with double nozzles,the mixing time is the shortest.Under the condition of double nozzles asymmetrical bottom blowing,when the insertion angle and depth of side lance are larger and deeper,the velocity streamline of molten slag layer is denser and the value is larger;meanwhile,the reflux of molten iron layer is larger,the proportion of dead zone is smaller,and the whole molten pool is fully stirred.When the insertion depth of the side lance is deeper,the gas holdup in the molten pool is greater and the stirring of the molten pool is more intense,while the insertion angle has little effect on the gas holdup.By comparing the influence of different side blowing conditions on the slag layer,it is found that the slag layer is divided into two layers by double-layer side lance,with the critical surface of the slag layer at about 200-260 mm from the bottom,and the insertion depth of the lower side lance has a greater influence on the layering of the slag.

石英晶体微天平在高分子研究中的应用

石英晶体微天平(QCM)作为一种强有力的表征工具已被广泛应用于高分子研究之中.本文中,作者介绍了QCM的发展简史、基本原理以及实验样品制备方法.在此基础上,介绍了如何基于带有耗散测量功能的石英晶体微天平(QCM-D)及相关联用技术研究界面接枝高分子构象行为、高分子的离子效应以及高分子海洋防污材料,展示了QCM-D技术在高分子研究中的广阔应用前景.QCM-D可同时检测界面高分子薄膜的质量变化和刚性变化,从而反映其结构变化.与光谱型椭偏仪联用后,还可同步获取界面高分子薄膜的厚度变化等信息,可以有效解决相关高分子研究中的问题.希望本文能够对如何利用QCM-D技术开展高分子研究起到一定的启示作用,使这一表征技术能够为高分子研究解决更多问题.

Interface-correlated Characteristics of Stainless Steel/Carbon Steel Plate Fabricated by AAWIV and Hot Rolling

Stainless steel （S S）/carbon steel （C S） clad plates were generated by means of the all-around weld of interface and vacuuming （AAWIV） followed by hot rolling, wherein AAWIV was utilized for controlling the interface oxidation during hot rolling. The structure near the interface was analyzed by optical microscopy （OM）, scanning electron mi- croscopy （SEM） and transmission electron microscopy （TEM）. The mechanical properties of SS/CS clad plates were investigated by tensile and shear as well as bend tests. The SS/CS interface is relatively flat and no visible separation appears. Line scanning analysis shows that diffusion of Cr and Ni from SS to CS and C from CS to SS occurred during bonding. Higher dislocation densities are observed in both layers of parent plates adhering to the interface. The SS/ CS clad plates reveal higher yield, tensile and shear strengths. Both macroscopic delamination at the interface and fracture of base CS as well as intergranular fracture appearance of flyer plate are observed in the tensile test. The shear specimen fails in a ductile manner and the bend specimen tested shows no visible crack at the interface. Taking both interracial structure and mechanical properties into account, the SS/CS clad plates exhibit sound bonding by the process of AAWIV and hot rolling.

Corrosion Behavior of the Ni-Cr-Fe Base Superalloy GH984G in a Synthetic Coal Ash and Flue Gas Environment

The corrosion behavior of the new Ni-Cr-Fe base superalloy GH984G in a synthetic coal ash and flue gas environments was studied at 700 ℃. The results showed that the corrosion rate was slow during the initial corrosion stage, then followed by a stage of faster mass loss. During the corrosion test, the scale trended to spall slightly, resulting in the formation of corrosion pits on the sample surfaces. The main corrosion products were identified as NiFeCrO4 and a small amount of Cr2O3. The scale microstructure involved the presence of three corrosion layers. The outer layer contained Cr, Ni, Fe, O and a small amount of S. Many micro-cracks were detected in the Cr-rich intermediate oxide layer. The inner corrosion layer was thin and rich in S. Internal sulfidation and internal oxidation occurred in the substrate. Because of its relatively high Cr content, the GH984G superalloy exhibited a good corrosion resistance under the test conditions.

Storage wall for exascale supercomputing

The mismatch between compute performance and I/O performance has long been a stumbling block as supercomputers evolve from petaflops to exaflops. Currently, many parallel applications are I/O intensive,and their overall running times are typically limited by I/O performance. To quantify the I/O performance bottleneck and highlight the significance of achieving scalable performance in peta/exascale supercomputing, in this paper, we introduce for the first time a formal definition of the ‘storage wall' from the perspective of parallel application scalability. We quantify the effects of the storage bottleneck by providing a storage-bounded speedup,defining the storage wall quantitatively, presenting existence theorems for the storage wall, and classifying the system architectures depending on I/O performance variation. We analyze and extrapolate the existence of the storage wall by experiments on Tianhe-1A and case studies on Jaguar. These results provide insights on how to alleviate the storage wall bottleneck in system design and achieve hardware/software optimizations in peta/exascale supercomputing.

The Anion Binding Affinity Determines the Strength of Anion Specificities of Thermosensitive Polymers

In this work,we demonstrate that the strength of anion specificities of thermosensitive polymers is determined by the affinity of direct anion binding to the polymers.We have prepared a series of thermosensitive statistical copolymers with distinct thermoresponsive behaviors.The anions can specifically interact with the different types of thermosensitive polymers in very different strengths.A similar strength of specific anion effects on thermoresponsive behaviors can be observed at very different salt concentrations for the different types of thermosensitive polymers.A stronger anion binding to the thermosensitive polymers gives rise to a more obvious anion specificity and vice versa.The work presented here opens up opportunities for the application of ion binding affinity to modulate the strength of ion specificities of thermosensitive polymers.

FTRP:基于进程复制和预取的高性能计算容错框架（英文）

随着超级计算机规模迅速增大,可靠性成为制约系统可用性的主要问题。现有容错机制,包括检查点技术和进程冗余等,不能有效解决该问题。为此,提出一种基于进程复制和预取的高性能计算容错框架—FTRP(fault tolerance framework using process replication and prefetching),该框架兼具主动和被动容错机制的优点,引入创新的开销模型和主动容错机制,能够有效改善应用运行效率。提出"工作最多"(work-most,WM)的创新开销模型,基于故障预测结果和应用状态,从容错机制集中在线自适应给出运行容错决策。与程序运行过程中的局部性相似,我们第一次观察到超级计算机故障局部性现象。基于故障局部性,提出一种新的进程复制和进程预取相结合的容错机制,无论故障能否被预测到,都能够有效避免故障引起的损失。通过基于实际故障路径和普通故障预测准确率的模拟实验,并采用FTRP容错框架的应用,可以获得比现有容错机制10%的改进,且在P级甚至更大规模系统上有效。

Revisiting the Thermosensitivity of Poly(acrylamide-co-diacetone acrylamide)

The lower critical solution temperature （LCST） behavior of poly（acrylamide-co-diacetone acrylamide） （poly（AM-co-DAM）） copolymer in aqueous solutions was studied. The results demonstrate the LCST linearly decreases as the molar fraction of DAM （fDAM） increases. In the range of fDAM 〈 0.36, the transmittance increases as fDAM decreases because the more hydrophilic copolymer chains can form looser aggregates with a lower refractive index. The transmittance exhibits a minimum when fDAM is less than 0.28 as the chains form micelle-like structure with a size smaller than the wavelength. The LCST decreases with the initial polymer concentration, but it levels off when the polymer concentration is high enough. Moreover, no hysteresis can be observed in the change of transmittance during the heating-cooling process because no additional hydrogen bonds are formed in the collapsed state due to the steric hindrance of the large side groups in DAM units.

Influence of hot rolling on microstructure and mechanical characteristics of explosive-welded FSS/CS laminate

The influence of hot rolling on the microstructure and subsequent mechanical characteristics of explosive-welded ferritic stainless steel （FSS）/carbon steel （CS） laminate was investigated. The results indicate that by hot rolling, decarburization layer disappears and a uniform structure is gained in CS side, but ferrite grains and carbides in constituent FSS form an uneven band microstructure which is denser at superficial zone than near the interface. The transmission electron microscopy results indicate that the layers adhering to the interface show typical deformed microstructure features, i.e., stream-like strips and elongated grains in FSS plates, carbide precipitates and bended cementite fragments in CS plates; and high-density dislocations in both plates, With hot rolling, various mechanical strengths and hardness are increased, while the elongation percentage is diminished. Examination of fractographs from tensile tests reveals predominately small dimples for explosive-welded specimens, whereas both big dimples and cleavage fracture for rolled specimens. Stereomicroscopic fractographs taken on shear samples indicate that the surfaces of explosive-welded specimens exhibit uniform deformation, but uneven deformation is displayed for that of rolled specimens. These results indicate that hot rolling is beneficial to improve the strength of explosive-welded FSS/CS laminate but not good for enhancing its plasticity.