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We describe fast recovery at a wavelength of 1550 nm in a multiple-quantum-well (MQW) saturable absorber with InGaAsP quaternary wells and barriers using electric-field-induced carrier sweepout. The MQW SA is integrated with a distributed Bragg reflector in a p-type–intrinsic–n-type structure. Pump–probe measurements show that the recovery time can be reduced from >900 to 28 ps by application of a 151 kV/cm sweepout field. We measure the dependence of the recovery time on the energy of the saturating pulse and explain our results in terms of carrier dynamics in the sweepout field. © 2001 American Institute of Physics. [ABSTRACT FROM AUTHOR]

OBJECTIVE: Malignant melanoma (MM), the deadliest form of skin malignancy, is a highly aggressive and malignant tumor with an increasing incidence rate in recent years. Increasing evidence suggested that dysfunctions of microRNAs (miRNAs) may play an important role in human tumors. However, the effect of miR-155 on malignant melanoma cell migration and invasion remains largely elusive. This research was designed to evaluate the potential function of miR-155 and CBL (Casitas B-lineage lymphoma) in malignant melanoma. PATIENTS AND METHODS: Quantitative Real-time polymerase chain reaction (qRT-PCR) was utilized to detect miR-155 and CBL expression in malignant melanoma tissues and cell lines. 3-(4, 5-dimethyl-2-thiazolyl)-2, 5-diphenyl-2-H-tetrazolium bromide (MTT) assay was performed to examine the regulation of miR-155 in melanoma proliferation. Transwell assay was carried out to detect the effect of miR-155 on the MM cell migration and invasion. Luciferase assay and biological analysis were used to predict and determine the target gene of miR-155. RESULTS: miR-155 was down-regulated in malignant melanoma tissues and cell lines. Ectopic expression of miR-155 could inhibit migration and invasion in malignant melanoma cells. What’s more, we found that CBL was a new target of miR-155. Additionally, CBL was negatively associated with miR-155 in malignant melanoma and overexpression of CBL attenuated miR-155-mediated inhibition on MM cell migration and invasion. CONCLUSIONS: miR-155 inhibited malignant melanoma proliferation, migration and invasion. And high CBL expression was observed in MM tissues. This newly identified miR-155/CBL axis may provide new insight into the pathogenesis of malignant melanoma. [ABSTRACT FROM AUTHOR]

This note presents a superconducting joint technique for the development of MgB2 magnetic resonance imaging (MRI) magnets. The MgB2 superconducting joint was fabricated by a powder processing method using Mg and B powders to establish a wire-bulk-wire connection. The joint resistance measured using a field-decay method was < 10-14 Ω, demonstrating that the proposed joint technique could be employed for developing "next-generation" MgB2 MRI magnets operating in the persistent current mode. [ABSTRACT FROM AUTHOR]

This paper reports the transient characteristics of two types of magnetically coupled GdBCO racetrack pancake coils: (1) a pair of insulated coils (INS–INS coils) and (2) a pair of non-insulated coils (NI–NI coils). In order to investigate the electromagnetic behavior of the INS–INS and NI–NI coils, charging/sudden discharging tests were performed with respect to the distance between primary and secondary coils of the coil pairs. The charging/sudden discharging test results show that the amount of induced current and measured axial magnetic field decreased with increasing distance between the primary and secondary coils. Additionally, charge and discharge delays were clearly observed in the NI–NI coils. The simulated results show good agreement with the experimental results, which validates the proposed approach involving an equivalent circuit model. [ABSTRACT FROM AUTHOR]

High Temperature Superconducting (HTS) synchronous motors consist mainly of rotational (HTS coil) and stationery (copper coil) parts. The HTS coil running at a synchronous speed is not influenced by the magnetic field generated by the stator coil but is affected considerably at the initial or transient operation. Therefore, computational analysis to determine the optimal design of the damper is an important factor in protecting the field coil of a HTS synchronous motor. This paper presents the optimal design parameters of the damper for a 5 MW HTS synchronous motor using the computational analysis of the transient characteristics of the stator current, which is proportional to the alternating magnetic field of the stator coil. [ABSTRACT FROM AUTHOR]