Enhanced response over wavelength range of 7-12 µm for quantum wells in asymmetric micro-pillars.

Efficient coupling in broad wavelength range is desirable for wide-spectrum infrared light detection, yet this is a challenge for intersubband transition in semiconductor quantum wells (QWs). High-Q cavities mostly intensify the absorption at peak wavelengths but with shrinking bandwidth. Here, we propose a novel approach to expand the operating spectral range of the Quantum Well Infrared Photodetectors (QWIPs). By processing the QWs into asymmetric micro-pillar array structure, the device demonstrates a substantial enhancement in spectral response across the wavelength from 7.1 µm to 12.3 µm with guided mode resonance (GMR) effects. The blackbody responsivity is then increased by 3 times compared to that of the 45° polished edge-coupled counterpart. Meanwhile, the dark current density remains unchanged after the deep etching process, which will benefit the electrical performance of the detector with reduced volume duty ratio. In contrast to the symmetric micro-pillar array that contains simple resonance mode, the detectivity of QWIP in asymmetric pillar structure is found to be improved by 2-4 times within the range of 9.5 µm to 15 µm.

Enhanced absorption of infrared light for quantum wells in coupled pillar-cavity arrays.

Periodic pillars of semiconductor in sub-wavelength size can serve multiple roles as diffracting, trapping and absorbing light for effective photoelectric conversion which has been intensively studied in the visible range. Here, we design and fabricate the micro-pillar arrays of AlGaAs/GaAs multi quantum wells(QWs) for high performance detection of long wavelength infrared light. Compared to its planar counterpart, the array offers 5.1 times intensified absorption at peak wavelength of 8.7 µm with 4 times shrinked electrical area. It's illustrated by simulation that the normal incident light is guided in the pillars by HE11 resonant cavity mode to form strengthened Ez electrical field, which enables the inter-subband transition of n-type QWs. Moreover, the thick active region of dielectric cavity that contains 50 periods of QWs with fairly low doping concentration will be beneficial to the optical and electrical merits of the detectors. This study demonstrates an inclusive scheme to substantially raise the signal to ratio of infrared detection with all-semiconductor photonic structures.

Circulating miR-765 and miR-149: potential noninvasive diagnostic biomarkers for geriatric coronary artery disease patients.

The purpose of this study was to evaluate the diagnostic value of circulating miR-765 and miR-149 as noninvasive early biomarkers for geriatric coronary artery disease (CAD) patients. A total of 69 angiographically documented CAD patients including 37 stable CAD (72.9 ± 4.2 years) and 32 unstable CAD (72.03 ± 4.3 years) and 20 healthy subjects (71.7 ± 5.2 years), matched for age, sex, smoking habit, hypertension, and diabetes, were enrolled in this study. Compared with healthy subjects, circulating miR-765 levels were increased by 2.9-fold in stable CAD and 5.8-fold in unstable CAD patients, respectively, while circulating miR-149 levels were downregulated by 3.5-fold in stable CAD and 4.2-fold in unstable CAD patients, respectively. Furthermore, plasma levels of miR-765 were found to be positively correlated with ages within control, stable, and unstable groups. The ROC curves of miR-765 and miR-149 represented significant diagnostic values with an area under curve (AUC) of 0.959, 0.972 and 0.938, 0.977 in stable CAD patients and unstable CAD patients as compared with healthy subjects, respectively. Plasma levels of miR-765 and miR-149 might be used as noninvasive biomarkers for the diagnosis of CAD in geriatric people.

Clinicopathologic features, treatment, and prognosis of postirradiation osteosarcoma in patients with nasopharyngeal cancer.

OBJECTIVES: Postirradiation osteosarcoma (PIOS) arising after radiation of nasopharyngeal cancer (NPC) is rare and seldom reported. In this article, we report its clinicopathologic features, outcome, and prognostic factors. STUDY DESIGN: Retrospective cohort study. METHODS: Fifteen patients with NPC were determined to have PIOS after reviewing 426 patients with osteogenic sarcomas. Their clinical records, image and pathologic slides, and follow-up data after treatment were collected to perform analysis. RESULTS: The incidence rate of PIOS in NPC was approximately 0.037% (15/40,719), which occupied approximately 3.5% (15/426) among all kinds of osteogenic sarcomas. The latent time of PIOS after irradiation for NPC ranged from 4 to 27 years, with a mean of 13.3 years. The location where PIOS arose included 33.3% (5/15) from maxilla, 46.7% (7/15) from mandible, and 20% (3/15) from a mixture of nasal cavity and paranasal sinuses. Radiologically, soft tissue mass, bone destruction, and tumor new bone formation were the main characteristics. Pathologic subtypes included 53.3% (8/15) of fibroblastic osteosarcoma, 33.3% (5/15) of chondroblastic osteosarcoma, and 13.3% (2/15) of mixed type osteosarcoma. Of 15 patients with PIOS, 12 patients were treated with curative intent, and the remaining 3 patients with palliative intent. For 12 patients who had undertaken ablative surgery, 1 patient had residual tumor, and 6 patients had tumor recurrence. The survival time after treatment for all patients ranged from 7 to 41 months, with a mean of 18 months. Kaplan-Meier estimates of 1 year and 2 year survival rates were 60% and 24%, respectively. Statistical analysis showed that sex and tumor bone formation are significant prognostic factors. CONCLUSIONS: PIOS in NPC is a highly malignant disease with poorer prognosis than in other sites. Surgery combined with pre- and postoperative chemotherapy might be an effective way to improve survival.