α-Actinin involvement in Z-disk assembly during skeletal muscle C2C12 cells in vitro differentiation

α-Actinin is involved in the assembly and maintenance of muscle fibers. α-Actinin is required to cross-link actin filaments and to connect the actin cytoskeleton to the cell membrane and it is necessary for the attachment of actin filaments to Z-disks in skeletal muscle fibers and to dense bodies in smooth muscle ones. In addition to its mechanical role, sarcomeric α-actinin interacts with proteins involved in a variety of signaling and metabolic pathways.The aim of this work is to monitor Z-disk formation, in order to clear up the role of sarcomeric α-actinin in undifferentiated stage, after 4 days of differentiation (intermediate differentiation stage) and after 7 days of differentiation (fully differentiated stage). For this purpose, C2C12 murine skeletal muscle cells, grown in vitro, were analyzed at three time points of differentiation.Confocal laser scanner microscopy and transmission electron microscopy have been utilized for α-actinin immunolocalization.Both techniques reveal that in undifferentiated cells labeling appears uniformly distributed in the cytoplasm with punctate α-actinin Z-bodies. Moreover, we found that when differentiation is induced, α-actinin links at first membrane-associated proteins, then it aligns longitudinally across the cytoplasm and finally binds actin, giving rise to Z-disks. These findings evidence α-actinin involvement in sarcomeric development, suggesting for this protein an important role in stabilizing the muscle contractile apparatus.     

α-Al_2O_3比表面积标准物质的研制

选择市售α-Al2O3粉体作为比表面积标准物质候选材料,采用交叉缩分方法对标准物质样品进行分装。检验结果表明α-Al2O3标准物质样品具有良好的均匀性和稳定性(18个月)。采用国际公认的氮气物理吸附BET方法,联合测量能力经过确认的8家实验室对α-Al2O3标准物质样品进行定值,标准值比表面积为5.47 m2/g,不确定度为0.22 m2/g(k=2)。     

One-step solution synthesis of Fe2O3 nanoparticles at low temperature

A new synthesis method of α-Fe₂O₃ nanoparticles was developed, in which the ferrous and ferric salts as well as polyaniline acted as the precursor and dispersant, respectively. From the investigation of X-ray diffraction and FT-IR spectra, the α-Fe₂O₃ nanoparticles can be directly prepared by the co-precipitation method without high-temperature calcining. Transmission electron microscope (TEM) and scanning electron microscope (SEM) observation revealed that the α-Fe₂O₃ nanoparticles had average diameters ranging from 30.0 to 75.0 nm. Compared with previous methods, this present method shows an easy processing and can be applied on the large-scale produce of α-Fe₂O₃ nanoparticles in one step.     

Determination of isospin asymmetry effects on α-decay

In this study,we compared the effect of the isospin asymmetry of proton and neutron density distributions in the neutron skin-type(NST) case and in the Hartree-Fock formalism(HF) on the half-life of alpha emitters with the atomic number in the range of 82≤Z≤92.The NST case and HF formalism based on the Skyrme-SLy4 effective interaction reveal different isospin asymmetries for selected alpha emitters.Furthermore,the obtained results reveal an increase in the α-decay widths of about 30% for the NST case in comparison with the equivalent values obtained by HF formalism.The standard deviations for calculated half-lives within the NST case and HF formalism are about 0.438 and 0.391,respectively.     

Effect of Butyl α-Hydroxymethyl Acrylate Monomer Structure on the Morphology Produced via Aqueous Emulsion Polymerization-induced Self-assembly

Polymerization-induced self-assembly(PISA) is an efficient and versatile method to afford polymeric nano-objects with polymorphic morphologies. Compared to dispersion PISA syntheses based on soluble monomers, the vast majority of emulsion PISA formulations using insoluble monomers leads to kinetically-trapped spheres. Herein, we present aqueous emulsion PISA formulations generating worms and vesicles besides spheres. Two monomers with different butyl groups, n-butyl(n BHMA) and tert-butyl(t BHMA) α-hydroxymethyl acrylate, and thus possessing different water solubilities were synthesized via Baylis-Hillman reaction. Photoinitiated aqueous emulsion polymerizations of n BHMA and t BHMA employing poly(ethylene glycol) macromolecular chain transfer agents(macro-CTAs, PEG45-CTA, and PEG113-CTA) at 40 °C were systematically investigated to evaluate the effect of monomer structure and solubility on the morphology of the generated block copolymer nano-objects. Higher order morphologies including worms and vesicles were readily accessed for t BHMA, which has a higher water solubility than that of n BHMA. This study proves that plasticization of the core-forming block by water plays a key role in enhancing chain mobility required for morphological transition in emulsion PISA.     

Micro/Nanoengineered α-Fe2O3 Nanoaggregate Conformably Enclosed by Ultrathin N-Doped Carbon Shell for Ultrastable Lithium Storage and Insight into Phase Evolution Mechanism

The Fe-based transition metal oxides are promising anode candidates for lithium storage considering their high specific capacity, low cost, and environmental compatibility. However, the poor electron/ion conductivity and significant volume stress limit their cycle and rate performances. Furthermore, the phenomena of capacity rise and sudden decay for α-Fe₂O₃ have appeared in most reports. Here, a uniform micro/nano α-Fe₂O₃ nanoaggregate conformably enclosed in an ultrathin N-doped carbon network (denoted as M/N-α-Fe₂O₃@NC) is designed. The M/N porous balls combine the merits of secondary nanoparticles to shorten the Li⁺ transportation pathways as well as alleviating volume expansion, and primary microballs to stabilize the electrode/electrolyte interface. Furthermore, the ultrathin carbon shell favors fast electron transfer and protects the electrode from electrolyte corrosion. Therefore, the M/N-α-Fe₂O₃@NC electrode delivers an excellent reversible capacity of 901 mA h g⁻¹ with capacity retention up to 94.0 % after 200 cycles at 0.2 A g⁻¹. Notably, the capacity rise does not happen during cycling. Moreover, the lithium storage mechanism is elucidated by ex situ XRD and HRTEM experiments. It is verified that the reversible phase transformation of α↔γ occurs during the first cycle, whereas only the α-Fe₂O₃ phase is reversibly transformed during subsequent cycles. This study offers a simple and scalable strategy for the practical application of high-performance Fe₂O₃ electrodes.     

反向高效色谱法测定维生素E中α-VE含量

采用反相高效液相色谱法测定维生素E中α-VE的含量。C18柱为色谱柱。甲醇/水（100∶0）为流动相,流速为1.0mL/min.检测波长为292nm。线性范围50—100μg/mL,r=0.9993,维生素E中α-VE的含量为84.82mg/L。本法操作简便,样品分离效果好,回收率高,结果准确可靠。     

On the convergence rate of grad-div stabilized Taylor-Hood to Scott-Vogelius solutions for incompressible flow problems

It was recently proven in Case et al. (2010) [2] that, under mild restrictions, grad-div stabilized Taylor-Hood solutions of Navier-Stokes problems converge to the Scott-Vogelius solution of that same problem. However, even though the analytical rate was only shown to be (where γ is the stabilization parameter), the computational results suggest the rate may be improvable to γ−1. We prove herein the analytical rate is indeed γ−1, and extend the result to other incompressible flow problems including Leray-α and MHD. Numerical results are given that verify the theory.     

A higher-order large-scale regularity theory for random elliptic operators

We develop a large-scale regularity theory of higher order for divergence-form elliptic equations with heterogeneous coefficient fields a in the context of stochastic homogenization. The large-scale regularity of a-harmonic functions is encoded by Liouville principles: The space of a-harmonic functions that grow at most like a polynomial of degree k has the same dimension as in the constant-coefficient case. This result can be seen as the qualitative side of a large-scale C^k,α-regularity theory, which in the present work is developed in the form of a corresponding C^k,α-“excess decay” estimate: For a given a-harmonic function u on a ball B_R, its energy distance on some ball B_r to the above space of a-harmonic functions that grow at most like a polynomial of degree k has the natural decay in the radius r above some minimal radius r₀.

Though motivated by stochastic homogenization, the contribution of this paper is of purely deterministic nature: We work under the assumption that for the given realization a of the coefficient field, the couple (φ, σ) of scalar and vector potentials of the harmonic coordinates, where φ is the usual corrector, grows sublinearly in a mildly quantified way. We then construct “kth-order correctors” and thereby the space of a-harmonic functions that grow at most like a polynomial of degree k, establish the above excess decay, and then the corresponding Liouville principle.