Poster: RANZCR ASM 2011 / R-0003 / Delineation of the Target Volume for Advanced Nasopharyngeal Carcinoma after Induction Chemotherapy: Clinical Outcomes and Patterns of Failure by: Y. Hua , F. Han, L. Lu, S. Wu, S. Huang, L. Chenguang, Z. Chong; Guangzhou/CN
P-type transition metal dichalcogenides (TMDCs) field-effect transistor (FET) with high performance is fundamental for the development of 2D electronic and optoelectronic devices. We achieve the effective p-type doping using toroidal-magnetic-field (TMF) controlled oxygen plasma on the six-layer MoS2. The bottom-gated MoS2 FET shows a record current on-off ratio of 107, a hole mobility of 115.2 cm2 V−1 s−1 and a subthreshold swing of 137 mV dec−1 at room temperature. The high performance is attributed to the negligible lattice defects and high substitutional rate through restricting the energy of oxygen ions, which are demonstrated by Raman spectroscopy, photoluminescence spectroscopy and x-ray photoelectron spectroscopy. The excellent p-type conduction is also beneficial from enhancing the ratio of ions in oxygen plasma by the TMF. First-principle calculations validate that ions lead to a shallow acceptor level at 42.16 meV above the valance band maximum and extracting 1.0 electron from MoS2 lattice. These findings provide a scheme for realizing 2D integrated circuit and excellent optoelectronic devices using MoS2 and other homogeneous TMDCs.
In this report, 4H-SiC p-i-n photodiodes with various micro-hole arrays are fabricated, then measured and discussed by using photoelectric measurement system and simulation software. Periodic micro-hole arrays etched from p layer to i layer are obtained by using the selective etching technology, which increases the photosensitive area of devices and reduces the ultraviolet light absorption of p layer. The average dark current of devices has an ultralow value of approximate $6.0\times 10 ^{-15}$ A in the low reverse bias range of 0–10 V. Furthermore, the device with $4 ~\mu \text{m}$ micro-hole exhibits the best performance and its peak responsivity increased by 10.4 % compared to the conventional device. It is significant that the peak responsivity and corresponding external quantum efficiency of devices with $4 ~\mu \text{m}$ micro-hole at 40 V bias are 815 % and 819 % higher than those of devices without micro-hole, respectively. This is attribute to the fact that a high electric field is observed around the micro-holes as the reverse bias increased to 40 V, which leads to local avalanche. Thus, the local avalanche photodiodes work at a relatively low bias, which improved the responsivity and quantum efficiency of the device enormously.
Monolayer MoS2 has excellent optoelectronic properties, which is a potential material for solar cell. Though MoS2/c-Si heterojunction solar cell has been researched by many groups, little study of MoS2/c-Si solar cell physics is reported. In this paper, MoS2/c-Si heterojunction solar cells have been designed and optimized by AFORS-HET simulation program. The various factors affecting the performance of the cells were studied in details using TCO/n-type MoS2/i-layer/p-type c-Si/BSF/Al structure. Due to the important role of intrinsic layer in HIT solar cell, the effect of different intrinsic layers including a-Si:H, nc-Si:H, a-SiGe:H, on the performance of TCO/n-type MoS2/i-layer/p-type c-Si/Al cell, was studied in this paper. The results show that the TCO/n-type MoS2/i-layer/p-type c-Si/Al cell has the highest efficiency with a-SiGe:H as intrinsic layer, efficiency up to 21.85%. The back surface field effects on the properties of solar cells were studied with p + μc-Si and Al as BSF layers. And the effect of various factors such as thickness and band gap of intrinsic layer, thickness of MoS2, density of defect state and the energy band offset of MoS2/c-Si interface of TCO/n-type MoS2/i-layer nc-Si:H/p-type c-Si/Al cells, on the characteristics of solar cells, have been discussed for this kind of MoS2 heterojunction cells. The optimal solar cell with structure of TCO/n-type MoS2/i-type nc-Si:H/p-type c-Si/BSF/Al, has the best efficiency of 27.22%.
In this brief, high-performance $8\times8$ arrays of 4H-SiC p-i-n ultraviolet (UV) photodiodes (PDs) with micro-hole structure are demonstrated. In order to improve the performance of the device, a periodic micro-hole structure (diameter = $4~\mu \text{m}$ ) was etched from the cap layer (p + layer) to the i layer, which will elevate the effective absorption of UV light. The pixels in 4H-SiC p-i-n array show a low dark current of less than $2\times 10^{-{14}}$ A and a high yield of 98.4%. Devices with 4- $\mu \text{m}$ micro-hole reach a peak spectral responsivity of 0.159 A/W at 280 nm, which is 23.3% higher than that of the device without micro-hole. Moreover, the device has a faster response time of 2.2 ns and a high UV/visible rejection ratio of more than $10^{{4}}$ . The progress on the response performance is significant to the development of UV detection imaging.
We fabricated GaN light-emitting diodes with a layer of graphene as a transparent electrode. A 3-nm-thick Al layer was deposited on the graphene layer by electron-beam evaporation. This Al layer plays an important role in protecting the graphene layer during the device fabrication process. Moreover, this Al layer can also enhance the light emission of GaN light-emitting diodes through the investigation of electroluminescence spectra. The significantly improved light emission is attributed to the current expansion, the enhanced plasmonic density of states, and the decreased non-radiative recombination rate.
Background: Radiotherapy and surgery are the standard local treatments for lung cancer brain metastases (BMs). However, limited studies focused on the effects of radiotherapy and surgery in lung cancer BMs with poor prognosis factors. Methods: We retrospectively analyzed 714 patients with lung cancer BMs. Analyses of overall survival (OS) and risk factors for OS were assessed by the log-rank test and Cox proportional hazard model. Results: Age ≥ 65 years, a Karnofsky Performance Scale (KPS) score ≤ 70, anaplastic large-cell lymphoma kinase (ALK)/epidermal growth factor receptor (EGFR) wild type, and extracranial metastases were related to poor prognosis. Patients were stratified according to these poor prognosis factors. In patients with the ALK/EGFR wild type, whole brain radiotherapy (WBRT), stereotactic radiosurgery (SRS), and surgery improved the OS of patients. WBRT and SRS were the independent protective factors for OS. In patients with extracranial metastases, patients who received WBRT plus SRS or WBRT alone had longer OS than those who did not receive radiotherapy. WBRT plus SRS and WBRT were the independent protective factors for OS. Conclusions: Radiotherapy and surgery are associated with improved survival for lung cancer BMs with the ALK/EGFR wild type. Radiotherapy is associated with improved survival in lung cancer BMs with extracranial metastases.
Objective To investigate the long-term outcome and prognostic factors of patients with nasopharyngeal carcinoma treated with intensity-modulated radiation therapy (IMRT). Methods From February 2001 to December 2006, 419 patients with nasopharyngeal carcinoma in Cancer Center of Sun yatsen University received IMRT. The number of patients with stage Ⅰ,Ⅱ,Ⅲ and Ⅳ disease was 28, 113, 202 and 76, respectively. In all, 182 and 237 patients received radiotherapy alone and chemoradiotherapy. The prescription doses were as follows:66-70 Gy/25 -30 f to GTV_(nx), 60 -64 Gy/25 -30 f to GTV_(nd), 55 -62 Gy/25 -30 f to CTV_1, and 42 -54 Gy/25 -30 f to CTV_2. Results The median follow-up time was 49 months (6 -94 months). The number of patients with follow-up of 1-, 3-, and 5-year were 419,360 and 166, respectively. Twenty-one, 13 and 57 patients had local recurrence, regional recurrence and distant metastasis, respectively. The 5-year local control (LC) rate, regional control (RC) rate and free from distant metastasis survival rate was 92.7%, 95.8% and 85.5%, respectively. The 5-year disease-free survival (DFS) and disease-specific survival (DSS) was 76. 3% and 84.4%, respectively. In univariate analysis, T stage, primary tumor volume, N stage and volume of cervical nodes before treatment were significant predictors of DFS and DSS, favoring the patients with early T stage (84. 1% vs. 67.6% ,Χ~2 = 12. 16, P = 0. 000 : 92. 1% vs. 75. 1% ,Χ~2 = 14. 86 . P = 0. 000) , primary tumor volume less than 20 cm~3 (89. 1% vs. 62. 9% ,Χ~2 =14. 13,P=0.000;96.2% vs. 72. 1% ,Χ~2 =38. 76,P=0.000), early N stage (81.1% vs. 64. 5%, Χ~2 = 15.49, P = 0. 000; 87. 8% vs. 76. 1%, Χ~2 = 10. 89, P = 0. 001) and volume of cervical nodes less than 5 cm~3 (83. 3% vs. 68. 8%, Χ~2 = 14. 13, P = 0. 000 ; 90. 0% vs. 78. 1%, Χ~2 = 10. 71 ,P =0. 001). Multivariate analysis showed that primary tumor volume (Χ~2 = 26. 81, P = 0. 000 and Χ~2 = 28. 47, P = 0. 000) and N stage (Χ~2 = 4. 92, P = 0. 026 and Χ~2 = 9.50, P = 0. 002) were independent predictive factors for both DFS and DSS. No grade 4 acute and late toxicities were observed. In 243 patients with follow-up time more than 3 years, only 2. 8% suffered from grade 3 late toxicifies. Conclusions IMRT with or without chemotherapy can improve the long-term survival of patients with nasopharyngeal carcinoma, especially in LC and RC. Distant metastasis becomes the main treatment failure. Primary tumor volume and N stage are significant prognostic factors. Acute and late toxicities are acceptable.
Key words:
Nasopharyngeal neoplasms/radiotherapy; Radiotherapy, intensity modulated; Prognostic analysis
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