Gene chip technology used in the detection of HPV infection in esophageal cancer of Kazakh Chinese in Xinjiang Province.

This study was aimed to screen human papillomavirus (HPV) types associated with esophageal squamous cell carcinoma of Kazakh in Xinjiang using the gene chip technique and study the clinical significance of this application. The DNAs were collected from esophageal squamous cell carcinoma tissues and healthy esophageal mucosa of Kazakh adults in Xinjiang, and amplified firstly using HPV MY09/11 and then using HPV G5+/6+ to screen positive HPV specimens. These positive specimens were further detected by the gene chip technique to screen highly pathogenic HPV types. After determination with nested PCR amplification with HPV MY09/11 and G5+/6+, the infection rate of HPV was 66.67% in the esophageal squamous cell carcinoma group and 12.12% in the healthy control group. By testing the positive HPV specimens from the esophageal squamous cell carcinoma group, the infection rate of HPV16 was 97.72% and the co-infection rate of HPV16 and HPV18 was 2.27%. HPV16 infection may be involved in the development of esophageal squamous cell carcinoma in Xinjiang Hazakh adults.

Broadband microwave Luneburg lens made of gradient index metamaterials.

Luneburg lenses are able to form perfect focus that is free of aberration. Because of the varying refractive index throughout the lens, incoming electromagnetic waves can travel in a curved path and be guided to focus at the back of the lens. The implementation of Luneburg lenses is often difficult due to the challenges in creating a medium with varying refractive index using normal materials. This problem can be overcome with the use of gradient index metamaterials. We report a two dimensional Luneburg lens made of gradient index metamaterials. It consists of 17 concentric shells with etched patterns on a printed circuit board working in microwave X band frequency. The broad properties of the Luneburg lens are then discussed.

High frequency dielectric properties distribution of BiFeO3 thin film using near-field microwave microscopy.

A near-field scanning microwave microscopy (NSMM) is applied to investigate the local perpendicular dielectric information of single-phase multiferroic BiFeO(3) thin film and single crystal LaAlO(3) material. Our NSMM is composed of a vector network analyzer and a simple open-ended coaxial probe, which is quite different from the commercial probe with a lambda/4 coaxial resonator. The local permittivity is calculated quantitatively according to resonance frequency shift under the quasistatic microwave perturbation theory. We make use of the magnitude of reflection loss S(11) to construct an image reflecting the distribution of dielectric constant of a material. A homogeneous permittivity is observed in LaAlO(3) material and the inhomogeneous permittivity epsilon=215-250 for BiFeO(3) film is depicted from the change of feedback signal S(11) over an area of 100x100 microm(2).

An omnidirectional retroreflector based on the transmutation of dielectric singularities.

Transformation optics is a concept used in some metamaterials to guide light on a predetermined path. In this approach, the materials implement coordinate transformations on electromagnetic waves to create the illusion that the waves are propagating through a virtual space. Transforming space by appropriately designed materials makes devices possible that have been deemed impossible. In particular, transformation optics has led to the demonstration of invisibility cloaking for microwaves, surface plasmons and infrared light. Here, on the basis of transformation optics, we implement a microwave device that would normally require a dielectric singularity, an infinity in the refractive index. To fabricate such a device, we transmute a dielectric singularity in virtual space into a mere topological defect in a real metamaterial. In particular, we demonstrate an omnidirectional retroreflector, a device for faithfully reflecting images and for creating high visibility from all directions. Our method is robust, potentially broadband and could also be applied to visible light using similar techniques.