Study on Downlink Spectral Efficiency in Orthogonal Frequency Division Multiple Access Systems

In previous studies on the capacity of orthogonal frequency division multiple access (OFDMA) systems, it is usually assumed that co-channel interference (CCI) from adjacent cells is a Gaussian-distributed random variable. However, very-little work shows that the Gaussian assumption does not hold true in OFDMA systems. In this paper, the statistical property of CCI in downlink OFDMA systems is studied, and spectral efficiency of downlink OFDMA system is analyzed based on the derived statistical model. First, the probability density function (PDF) of CCI in downlink OFDMA cellular systems is studied with the considerations of path loss, multipath fading and Gaussian-like transmit signals. Moreover, some closed-form expressions of the PDF are obtained for special cases. The derived results show that the PDFs of CCI are with a heavy tail, and significantly deviate from the Gaussian distribution. Then, based on the derived statistical properties of CCI, the downlink spectral efficiency is derived. Numerical and simulation results justify the derived statistical CCI model and spectral efficiency.Comment: 23 pages, 8 figures, IET Communications, 201

Analysis on Wind Environment in Winter of Different Rural Courtyard Layout in the Northeast

AbstractThrough to survey the northeast region in China, summarized four kinds of typical rural courtyard layout forms. Using Fluent software to simulate the wind velocity of different layout forms, combined with the assessment criteria of wind velocity ratio, considering factors such as the wind shadow area and the numbers of eddy current, to analyze advantages and disadvantages of wind environment in existing courtyard

Tetra­kis(μ2-phenyl­acetato-κ2 O:O′)bis­[(isoquinoline-κN)copper(II)]

In the title centrosymmetric binuclear CuII complex, [Cu2(C8H7O2)4(C9H7N)2], the two Cu cations are bridged by four carboxyl­ate groups of the phenyl­acetate anions; each Cu cation is further coordinated by an isoquinoline ligand to complete the distorted CuO4N square-pyramidal geometry. The Cu cation is displaced by 0.2092 (8) Å from the basal plane formed by the four O atoms. Within the dinuclear mol­ecule, the Cu⋯Cu separation is 2.6453 (6) Å. Although a parallel, overlapped arrangement of isoquinoline ligands exists in the crystal structure; the longer face-to-face distance of 3.667 (5) Å suggests there is no π–π stacking between isoquinoline ring systems

Pemetrexed plus cisplatin/carboplatin in previously treated locally advanced or metastatic non-small cell lung cancer patients

<p>Abstract</p> <p>Background</p> <p>The objective of this study was to evaluate the efficacy and safety of pemetrexed plus cisplatin/carboplatin in locally advanced or metastatic non-small cell lung cancer (NSCLC) patients previously treated with platinum-based chemotherapy.</p> <p>Methods</p> <p>Fifty-three locally advanced or metastatic non-small cell lung cancer patients previously treated with platinum-based chemotherapy received pemetrexed 500 mg/m²plus cisplatin 75 mg/m²or carboplatin area under the curve (AUC) 5 every 21 days, with dexamethasone, folic acid and vitamin B12 being administered.</p> <p>Results</p> <p>Median age was 52 years. Eastern Cooperative Oncology Group (ECOG) performance status was 0-2. Thirty-eight patients had stage IV tumors. Thirty-seven patients had adenocarcinoma (including 6 alveolar carcinoma patients), and fourteen patients had squamous cell carcinoma. Thirty-four patients were treated in second line, 15 in third line, and 4 in fourth line. Seven patients (13.2%) showed partial response; Thirty-six (67.9%) had stable disease. The median progression free survival time was 6.0 months and the median overall survival time was 10.0 months. The 1-year survival rate was 40.9%. Five (9.4%) and four (7.5%) patients experienced grade 3 or 4 leukopenia and thrombocytopenia, respectively. Nonhematological toxicities included grade 3 nausea/vomiting in 1 patient (1.9%), grade 3 rash in 1 patient, grade 4 diarrhea in 1 patient (1.9%) and grade 4 creatinine increase in 1 patient (1.9%).</p> <p>Conclusion</p> <p>Locally advanced or metastatic NSCLC patients previously treated with platinum-based chemotherapy could benefit from pemetrexed plus cisplatin/carboplatin chemotherapy with tolerable adverse events.</p

Targeting HSP90 in ovarian cancers with multiple receptor tyrosine kinase coactivation

<p>Abstract</p> <p>Background</p> <p>Ovarian cancer has the highest mortality rate of all gynecologic malignancy. The receptor tyrosine kinases (RTKs), including EGFR, ERBB2, PDGFR, VEGFR and MET, are activated in subsets of ovarian cancer, suggesting that these kinases might represent novel therapeutic targets. However, clinical trials have not or just partially shown benefit to ovarian cancers treated with EGFR, ERBB2, or PDGFR inhibitors. Despite multiple RTK activation in ovarian cancer pathogenesis, it is unclear whether transforming activity is dependent on an individual kinase oncoprotein or the coordinated activity of multiple kinases. We hypothesized that a coordinated network of multi-RTK activation is important for the tumorigenesis of ovarian cancers.</p> <p>Results</p> <p>Herein, we demonstrate co-activation of multiple RTKs (EGFR, ERBB2, ERBB4, MET and/or AXL) in individual ovarian cancer cell lines and primary tumors. We also show that coordinate inhibition of this multi-kinase signaling has substantially greater effect on ovarian cancer proliferation and survival, compared to inhibition of individual activated kinases. The inhibition of this multi-RTK signaling by HSP90 suppression results in profound pro-apoptotic and anti-proliferative effects, and is associated with the inactivation of RTK downstream PI3-K/AKT/mTOR and RAF/MAPK signaling.</p> <p>Conclusion</p> <p>These studies suggest that anti-multiple RTK strategy could be useful in the treatment of ovarian cancer.</p