Performance improvement of ultraviolet-A multiple quantum wells using a vertical oriented nanoporous GaN underlayer.

Well-aligned, lateral and vertical oriented nanoporous GaN was fabricated using the electrochemical etching procedure and its influence on the optical characteristics of ultraviolet-A multiple quantum well (MQW) structure was investigated. We used a MQW structure with a V-defect and n-Al0.1Ga0.9 N layer, which greatly improved the uniformity of vertical electrochemical etching. Compared to the as-grown MQW structure, the lateral and vertical oriented nanoporous MQW structures have 3.8-fold and 8.1-fold photoluminescence intensity enhancement and the full width at half maximum has been narrowed from 18.4 nm to 7.9 nm and 2.8 nm, respectively. The vertical oriented nanoporous MQW structure has a rectangular far-field emission pattern with uniform forward light distribution and the view angle of 85% intensity is 50°. This study provides an effective method for improving the light output and controlling the emission angle of GaN based light emitting devices, as well as a method for preparing well-aligned nanopores in semiconductors.

Super flexible GaN light emitting diodes using microscale pyramid arrays through laser lift-off and dual transfer.

We demonstrated a method to obtain super flexible LEDs, based on high quality pyramid arrays grown directly on sapphire substrates. Laser lift-off (LLO) and dual transfer processes were applied to transfer pyramid arrays face up onto the flexible substrates, which is more efficient than back light emission. Ag grid and Ag nanowires were employed as the electrical connection. No significant performance reduction appeared until the device reached a curvature radius of 0.5 mm. The performance reduction results from cracks appearing at the junction of the Ag grid, which can be improved by replacing the Ag grid with a strip electrode.

Reproductive Hormones and Their Receptors May Affect Lung Cancer.

BACKGROUND/AIMS: In contrast to men, women have experienced a rapid increase in lung cancer mortality. Numerous studies have found that the sex differences in lung cancer are due to reproductive hormones. Experiments in female mice with and without ovariectomy were performed to explore the possible mechanism by which sex hormones (and their receptors) influence lung cancer. METHODS: Twenty-four female C57BL/6 mice aged 56-62 days were randomly divided into the ovariectomized group and the control group. In the ovariectomized group, the bilateral ovaries were removed via the dorsal approach, while the control group underwent a sham operation with bilateral ovarian fat resection at the same sites. After 3 weeks of recovery, Lewis lung cancer cells were transplanted into these mice by subcutaneous inoculation of a tumour cell suspension to establish the ovariectomized lung cancer model. Beginning on the 6th day after subcutaneous inoculation, mouse weight and transplanted tumour volume were measured every 3 days. After 3 weeks, all the mice were killed by cervical dislocation, and we measured the tumour weight. Mouse serum and tumour tissues were removed. Then, the serum levels of E2 (oestradiol) and T (testosterone) were detected by ELISA; the protein expression levels of AR (androgen receptor), ERα (oestrogen receptor α) and ERß (oestrogen receptor ß) were detected by Western Blot and IHC (immunohistochemistry); and the mRNA expression levels of AR, ERα and ERß were detected by qRT-PCR (quantitative real-time polymerase chain reaction) in the ovariectomized and control groups. RESULTS: Compared with the control group, both mouse weight and transplanted tumour volume increased rapidly in the ovariectomized group, and the transplanted tumour weight was significantly heavier in the ovariectomized group (1.83±0.40 and 3.13±0.43, P<0.05). E2 and T serum levels decreased exponentially in the ovariectomized group, while the E2/T ratio increased compared with the control group (E2: 55.88±11.45 and 78.21±9.37; T: 0.82±0.14 and 1.46±0.16; ratio: 69.62±14.43±29.81 and 52.22±5.42; all P<0.05). The Western blot and IHC results indicated that AR, ERα and ERß protein expression levels were obviously higher in transplanted tumour and lung tissues from the ovariectomized group, with particular increases in ERß in transplanted tumour tissue and in ERα in lung tissue. The PCR results also showed markedly higher mRNA expression levels of AR, ERα and ERß in the ovariectomized group, and in particular, ERß in transplanted tumour tissue and ERα in lung tissue were significantly increased in the ovariectomized group. CONCLUSION: Ovariectomy decreased E2 and T serum levels and increased the E2/T ratio in mice, and this imbalance in the internal environment promoted the growth of transplanted tumours. Sex hormone disorder not only promoted transplanted tumour growth but also significantly reduced the protein and mRNA expression levels of sex hormone receptors. The metabolism of E2 and T may affect the growth, proliferation and metabolism of lung cancer cells, and the mechanism by which sex hormones and their receptors influence lung cancer is worthy of further research.

Insulin induces C2C12 cell proliferation and apoptosis through regulation of cyclin D1 and BAD expression.

Insulin is a secreted peptide hormone identified in human pancreas to promote glucose utilization. Insulin has been observed to induce cell proliferation and myogenesis in C2C12 cells. The precise mechanisms underlying the proliferation of C2C12 cells induced by insulin remain unclear. In this study, we observed for the first time that 10 nM insulin treatment promotes C2C12 cell proliferation. Additionally, 50 and 100 nM insulin treatment induces C2C12 cell apoptosis. By utilizing real-time PCR and Western blotting analysis, we found that the mRNA levels of cyclinD1 and BAD are induced upon 10 and 50 nM/100 nM insulin treatment, respectively. The similar results were observed in C2C12 cells expressing GATA-6 or PPARα. Our results identify for the first time the downstream targets of insulin, cyclin D1, and BAD, elucidate a new molecular mechanism of insulin in promoting cell proliferation and apoptosis.

Nanoscale Characterization of V-defect in InGaN/GaN QWs LEDs using Near-Field Scanning Optical Microscopy.

The size of the V-defects in the GaN/InGaN-based quantum wells blue light-emitting diode (LED) was intentionally modified from 50 nm to 300 nm. High resolution photoluminescence and electroluminescence of a single large V-defect were investigated by near-field scanning optical microscopy. The current distribution along the {10-11} facets of the large defect was measured by conductive atomic force microscopy. Nearly 20 times the current injection and dominant emission from bottom quantum wells were found in the V-defect compared to its vicinity. Such enhanced current injection into the bottom part of quantum wells through V-defect results in higher light output power. Reduced external quantum efficiency droops were achieved due to more uniform carrier distribution. The un-encapsulated fabricated chip shows light output power of 172.5 mW and 201.7 mW at 400 mA, and external quantum efficiency drop of 22.3% and 15.4% for the sample without and with large V-defects, respectively. Modified V-defects provide a simple and effective approach to suppress the efficiency droop problem that occurs at high current injection, while improving overall quantum efficiency.

Epidemiological evidences from China assume that psychiatric-related diseases may be associated with Toxoplasma gondii infection.

In recent years, the effect of Toxoplasma gondii infection on psychiatric-related aspects has been increasingly recognized. T. gondii has a high affinity for brain tissue where tachyzoites may form tissue cysts and persist life long. In recent years, 15 serological surveys about T. gondii infection and psychiatric diseases have been carried out in different areas in China. Studies showed that the prevalence of antibodies against T. gondii in psychotic patients was much higher than in normal persons; statistically differences were significant. Studies also reported that raising cats or enjoying the habit of eating raw or under cooked meet were potential risk factors for the infection of T. gondii. The epidemiological and serological evidence support the hypothesis that some psychiatric diseases such as schizophrenia or mental retardation might be linked to T. gondii infection.

Metamaterial study of quasi-three-dimensional bowtie nanoantennas at visible wavelengths.

In this paper, a novel array of quasi-three-dimensional (quasi-3D) bowtie nanoantennas has been investigated numerically and experimentally. A low-cost and facile method has been designed and implemented to fabricate the quasi-3D bowtie nanoantennas. The fabrication processes containing laser patterning and wet etching have demonstrated the advantages of easily tuning the periodic and diameter of microhole arrays. According to the simulated results, the electric and magnetic resonances at visible wavelengths are obtained in the tips and contours of the metamaterials made of the quasi-3D bowtie nanoantennas, respectively. The effects of the size and gap of quasi-3D bowtie nanoantennas on the array performance have also been studied. The underlying mechanism suggests that different electric and magnetic resonant ranges of the metamaterials could contribute to the broad resonant range for the monolithic metamaterials.

[Pathologic and X-ray features of primary malignant fibrous histiocytoma of bone--a report of 16 cases].

BACKGROUND & OBJECTIVE: Malignant fibrous histiocytoma (MFH) is a common soft tissue tumor, which rarely occur in the skeleton. Its histological origin still remains controversial. This study was to investigate the pathologic and X-ray features of primary MFH of bone, and provide reference for imaging diagnosis. METHODS: Clinical data and X-ray images of 16 MFH patients, treated from Jan. 1982 to Jun. 2002 in the First Affiliated Hospital of Soochow University, were analyzed retrospectively. RESULTS: Pathologic manifestations of the patients were malignant multinucleated giant cells, pleomorphic and bizarre form of the tumor cells, and wheel-spoke arrangement of the fibroblast-like cells. Pathologically, the tumor tissue was consisted of various kinds of cells, which were mainly fibroblasts and histiocytes. The principal X-ray manifestations included solitary osteolytic changes, cortical expansion around the tumor, the penetration of the cortex with soft tissue mass formation, slight periosteal reaction and pathologic fracture. CONCLUSION: The diagnosis of MFH mainly depends on pathologic examination and X-ray manifestations.