Icosahedral DNA Nanocapsules by Modular Assembly

It's a trap! DNA polyhedra formed through molecular self‐assembly may function as nanocapsules for the targeted delivery of encapsulated entities. This functional aspect was demonstrated for the most complex DNA‐based platonic solid: During the stepwise amalgamation of discrete polyhedra to form icosahedra, gold nanoparticles (GNPs) were encapsulated from solution (see illustration and TEM image of icosahedral cages containing GNPs).

     

Scattering of quasi-one-dimensional solitons on impurities in large Josephson junctions

Fluxon transmission through impurities of different shape in a quasi-one-dimensional long Josephson junction is investigated. The junction width is significantly less than its length but, at the same time, is of the order of the Josephson penetration length _λJ${\lambda }_J$ or exceeds it. The retrapping current on the impurities of the point, line and rectangular shape is computed as a function of the junction width both numerically and analytically. Good agreement between the analytic formulae and the numerical simulation results for the intermediate (several _λJ${\lambda }_J$) junction width is observed.     

CuO薄膜的制备及其光伏特性

通过反应磁控溅射在n型硅和玻璃衬底上制备了p型CuO薄膜.使用X射线衍射仪和紫外-可见光-近红外光度计研究了p型CuO薄膜的结构和光学特性,得出其平均晶粒尺寸和光学带隙分别为8nm和1.36eV.通过研究其电压-电流关系确定了在p型CuO薄膜和n型硅衬底之间形成了p-n结.在AM 1.5光照条件下p-CuO/n-Si电池的开路电压为0.33V,短路电流密度为6.27mA/cm2,填充因数和能量转化效率分别为0.2和0.41%.     

利用倾斜角度蒸发法制备Al/Al2O3/Al超导隧道结

利用电子束曝光法对双层光刻胶进行曝光来制备悬空掩模结构,在此基础上利用电子束蒸发系统采用倾斜角度蒸发法制备铝超导薄膜,采用热氧化法在底层铝膜表面形成氧化铝作为势垒层,制备出铝SIS超导隧道结,并在360mK的情况下对铝结进行了Ⅰ～Ⅴ特性的初步测量.铝隧道结的成功制备为下一步构建超导量子比特器件,研究其量子特性奠定了良好的基础.     

Apical acidity decreases inhibitory effect of omeprazole on Mg2+ absorption and claudin-7 and -12 expression in Caco-2 monolayers

Clinical studies reported hypomagnesaemia in long-term omeprazole usage that was probably due to intestinal Mg²⁺ wasting. Our previous report demonstrated the inhibitory effect of omeprazole on passive Mg²⁺ transport across Caco-2 monolayers. The present study aimed to identify the underlying mechanism of omeprazole suppression of passive Mg²⁺ absorption. By using Caco-2 monolayers, we demonstrated a potent inhibitory effect of omeprazole on passive Mg²⁺, but not Ca²⁺, transport across Caco-2 monolayers. Omeprazole shifted the %maximum passive Mg²⁺ transport-Mg²⁺ concentration curves to the right, and increased the half maximal effective concentration of those dose-response curves, indicating a lower Mg²⁺ affinity of the paracellular channel. By continually monitoring the apical pH, we showed that omeprazole suppressed apical acid accumulation. Neomycin and spermine had no effect on passive Mg²⁺ transport of either control or omeprazole treated monolayers, indicating that omeprazole suppressed passive Mg²⁺ transport in a calcium sensing receptor (CaSR)-independent manner. The results of western blot analysis showed that omeprazole significantly suppressed claudin (Cldn)-7 and -12, but not Cldn-2, expression in Caco-2 cells. By using apical solution of pH 5.5, 6.0, 6.5, and 7.0, we found that apical acidity markedly increased passive Mg²⁺ transport, Mg²⁺ affinity of the paracellular channel, and Cldn-7 and -12 expression in Caco-2 monolayers. Apical acidity abolished the inhibitory effect of omeprazole on passive Mg²⁺ transport and Cldn-7 and -12 expression. Our results provided the evidence for the regulation of intestinal passive Mg²⁺ absorption by luminal acidity-induced increase in Cldn-7 and -12 expression.     

Growth and characterisation of diffusion junctions between paired gold electrodes: diffusion effects in generator–collector mode

A diffusion junction between two paired gold electrodes is created in a bipotentiostatic electro-deposition process. Gold metal is deposited simultaneously on two adjacent disc electrodes (100 μm diameter, approximately 125 μm separation) until short-circuit conditions trigger the end point of the electro-deposition. Symmetric gold junctions with typically 5 μm average inter-electrode gap size, 140 μm gap length, and approximately 18 μm junction depth are obtained. These paired gold electrodes are employed in generator–collector mode to give well-defined steady-state feedback currents even for extremely low concentrations of analyte (sub-μM) and without any contributions from capacitive charging. Four redox systems are investigated spanning a wide range of diffusion coefficients: (1) the one-electron oxidation of iodide to iodine, (2) the two-electron oxidation of hydroquinone to benzoquinone, (3) the two-electron reduction of alizarin red S, and (4) the one-electron oxidation of the redox protein cytochrome c. Consistent results for these redox systems suggest that (1) the junction zone between the two electrodes is dominating the behaviour of the electrode in particular for the slower diffusing systems and (2) the paired gold electrode junction can be calibrated and employed for electroanalysis at very low concentrations and for a wider range of analytically relevant redox systems. Dedicated to Professor Keith B. Oldham, on the occasion of his 80th birthday     

Progress in high-linearity multi-element Josephson structures

This paper summarizes both theoretical and experimental studies aimed at synthesis of high-linearity multi-element Josephson structures. Both the dynamic range and the voltage response linearity are two conjugated characteristics that must be improved jointly. Increase in dynamic range is reasonably associated with increase of number of elements N in the Josephson-junction structures. To improve the voltage response linearity one can use special design of the array structures. The other way is based on use novel basic cell with is bi-SQUID capable of providing highly linear voltage response. Both the approaches were used in designs of the reported high-linearity multi-element Josephson structures.     

Energy‐Level Alignment for Single‐Molecule Conductance of Extended Metal‐Atom Chains

The use of single‐molecule junctions for various functions constitutes a central goal of molecular electronics. The functional features and the efficiency of electron transport are dictated by the degree of energy‐level alignment (ELA), that is, the offset potential between the electrode Fermi level and the frontier molecular orbitals. Examples manifesting ELA are rare owing to experimental challenges and the large energy barriers of typical model compounds. In this work, single‐molecule junctions of organometallic compounds with five metal centers joined in a collinear fashion were analyzed. The single‐molecule i–V scans could be conducted in a reliable manner, and the E_FMO levels were electrochemically accessible. When the electrode Fermi level (E_F) is close to the frontier orbitals (E_FMO) of the bridging molecule, larger conductance was observed. The smaller |E_F?E_FMO| gap was also derived quantitatively, unambiguously confirming the ELA. The mechanism is described in terms of a two‐level model involving co‐tunneling and sequential tunneling processes.     

电化学门控调节具有平行路径的单分子电路中电子传输

电化学门控已成为一种可行且高效调节单分子电导的方法.在本研究中,我们证实了具有两个平行苯环的单分子电路中电子传输可以通过电化学门控控制.首先,我们利用STM-BJ技术以金为电极构筑了具有两条平行路径的单分子结.与单条路径的单分子结相比,两条路径的分子结由于具有增强性量子干涉效应,具有2.82倍的电导值.进一步地,我们利...