Nano

We describe a strategy to construct three-dimensional (3D) containers with nanoporous walls by the self-assembly of lithographically patterned two-dimensional cruciforms with solder hinges. The first step involves fabricating two-dimensional (2D) cruciforms composed of six unlinked patterns: each pattern has an open window. The second step entails photolithographic patterning of solder hinges that connect the cruciform. The third step involves the deposition of polystyrene particles within the windows and the subsequent electrodeposition of metal in the voids between the polystyrene particles. Following the dissolution of the particles, the cruciforms are released from the substrate and heated above the melting point of the solder causing the cruciforms to spontaneously fold up into 3D cubic containers with nanoporous walls. We believe these 3D containers with nanoporous side walls are promising for molecular separations and cell-based therapies.

An improved hydrogen adsorption capacity of 0.5–0.6 wt% was obtained at room temperature and 10.0 MPa pressure for commercial MWNT sample by γ-ray irradiation, compared with 0.33 wt% of pristine MWNTs. The irradiation-induced defects in structure, which is favorable for hydrogen adsorption, were characterized by ESR spectrum, elemental analysis, and Raman spectrum. The results show that γ-ray irradiation increased the hydrogen adsorption capacity due to the increasing number of defects created by γ-photons, but would reach the maximum when defect concentration achieves saturation.

This paper introduces an accurate analysis of time domain response of carbon nanotube (CNT) interconnects based on distributed RLC model that takes the effect of both the series resistance and the output parasitic capacitance of the driver into account. Using rigorous principle calculations, accurate expressions for the transfer function of these lines and their time domain response have been presented. It has been shown that the second-order transfer function cannot represent the distributed behavior of the long CNT interconnects, and the fourth-order approximation offers a better result. Also, the time response of a driven long CNT interconnect versus length and diameter have been studied. The obtained results show that the overshoot increases and the time delay decreases with increasing the CNT diameter, such that with the diameter value of 10 nm for a 3.3 mm CNT interconnect, the maximum overshoot value reaches about 95% of the amplitude of the driver input. On the contrary, the overshoot increases and the time delay decreases with decreasing the length of the CNT, such that with the length value of 1 mm for a 5 nm diameter CNT interconnect, the maximum overshoot reaches about 90% of the amplitude of the driver input.

Two-photon optical nonlinear absorption has been studied in quantum dots of CdS_xSe_1-x grown in borosilicate glass matrix by two-step annealing technique. Femtosecond laser and open aperture Z-scan technique has been used for measuring the third-order nonlinear two-photon absorption coefficient (β⁽³⁾). Only the third-order and not the fifth-order nonlinear effects are observed at low intensities (1.6–3.2 GW cm^-2) of laser used in the present experiment. At such low intensities, the variation of β⁽³⁾ is found to be almost intensity-independent. For a given annealing duration of the quantum dots, the value of β⁽³⁾ is found to be higher for sulfur-rich samples as compared to that for selenium-rich samples. This is attributed to the presence of shallow traps formed due to sulfur vacancies in the sulfur-rich samples. Further, the value of β⁽³⁾ increases with the increase in the size of quantum dots and the rate of increase of β⁽³⁾ with the increase of average radius is found to be higher for sulfur-rich samples.

In the present paper the conditions to increase both the sharpness of the p–n-junctions, which produced as the elements of a system of rectifiers, and homogeneity of impurity concentrations in doped areas are determined. Moreover the development of a mathematical approach for analysis of dopant dynamics during annealing of dopant or radiation defects is presented. Annealing time has been optimized for increasing simultaneously the sharpness and the homogeneity.

We study the motion of domain wall in round marks formed in an exchange-coupled CoNi/Pt film, suitable for perpendicular magnetic recording. Marks were written by probe-based magnetic recording, with an average size of 180 nm. By applying external magnetic field on those marks, they begin to shrink. The minimum field required to move the domain wall of marks, i.e., domain wall coercivity, is 60% the nucleation coercivity of the medium. A model of dynamic domain motion was executed to study the stability of magnetic domains in exchange-coupled perpendicular media. It shows that the domain wall coercivity is a better fit than the nucleation coercivity to calculate the minimum stable domain size of the medium.

Cinobufagin-loaded bovine serum albumin nanoparticles were prepared for treating hepatocellular carcinoma. In this report, cinobufagin-bovine serum albumin-nanoparticles (Cino-BSA-NP) were prepared by an aqueous desolvation process. The physicochemical properties, toxicity, and cancer-related applications of Cino-BSA-NP were investigated. Cino-BSA-NP had a uniform spherical morphology with a particle size in the range of 50–240 nm and an average size of 86.3 nm. The zeta potential of the nanoparticles was -49 mV. The overall embedding ratio was 79.5% and the drug loading was 24.1%. Cino-BSA-NP gave cinobufagin release of up to 53.5% within 3 h, followed by slower controlled release. Cino-BSA-NP inhibited growth of hepatocarcinoma cells in vitro to a similar extent as free cinobufagin, but with a much higher median lethal dose (LD₅₀). Hepatic histomorphological changes indicated that hepatic damage was much less severe with Cino-BSA-NP than with free cinobufagin (2.19 mg/kg). The survival time of nude mice with orthotopic transplantation tumors treated with Cino-BSA-NP was prolonged significantly. The results confirm that Cino-BSA-NP renders cinobufagin completely dispersible in aqueous media, meeting the key requirements for intravenous injection, and show controlled release, thus significantly improving cinobufagin's antitumor activity while reducing its side effects.