Comparison of Multi-Channel Nonlinear Equalization using Inverse Volterra Series versus Digital Backpropagation in 400 Gb/s Coherent Superchannel

We investigate the performance of a Volterra-based nonlinear equalizer and the digitalbackpropagation (DBP) method in multi-channel nonlinear equalization after 20×80 km transmission distance. The Volterra equalizer, which operates with single-step-per-span, performs similarly compared to DBP with 40 steps-per-span

Comparison of Linear and Nonlinear Equalization for Ultra-High Capacity Spectral Superchannels

In ultra-high-speed (>400Gb/s per wavelength), high-spectral efficiency coherent optical communication systems using multi-carrier spectral superchannels, the maximum reach is severely limited due to linear and, foremost, nonlinear impairments. Hence, the implementation of advanced digital signal processing (DSP) techniques in optical transceivers is crucial for alleviating the impact of such impairments. However, the DSP performance improvement comes at the expense of increased cost and power consumption. Given that the computational complexity of the applied linear and nonlinear equalizers is the factor that determines the trade-off between the performance improvement and cost, in this study we provide an extended analysis on the computational complexity of various linear and nonlinear equalization approaches. First, we draw a complexity comparison between a conventional OFDM coherent receiver versus a filter-bank based OFDM receiver and it is shown that the latter provides significant complexity savings. Second, we present a comparison between the digital back-propagation split-step Fourier (DBP-SSF) method and the inverse Volterra series transfer function nonlinear equalizer (IVSTF-NLE) in terms of performance and computational complexity for a 32 Gbaud polarization multiplexed (PM)-16 quadrature amplitude modulation (QAM) OFDM superchannel

The relationship between the systemic inflammatory response, tumour proliferative activity, T-lymphocytic and macrophage infiltration, microvessel density and survival in patients with primary operable breast cancer

The significance of the inter-relationship between tumour and host local/systemic inflammatory responses in primary operable invasive breast cancer is limited. The inter-relationship between the systemic inflammatory response (pre-operative white cell count, C-reactive protein and albumin concentrations), standard clinicopathological factors, tumour T-lymphocytic (CD4+ and CD8+) and macrophage (CD68+) infiltration, proliferative (Ki-67) index and microvessel density (CD34+) was examined using immunohistochemistry and slide-counting techniques, and their prognostic values were examined in 168 patients with potentially curative resection of early-stage invasive breast cancer. Increased tumour grade and proliferative activity were associated with greater tumour T-lymphocyte (P<0.05) and macrophage (P<0.05) infiltration and microvessel density (P<0.01). The median follow-up of survivors was 72 months. During this period, 31 patients died; 18 died of their cancer. On univariate analysis, increased lymph-node involvement (P<0.01), negative hormonal receptor (P<0.10), lower albumin concentrations (P<0.01), increased tumour proliferation (P<0.05), increased tumour microvessel density (P<0.05), the extent of locoregional control (P<0.0001) and limited systemic treatment (Pless than or equal to0.01) were associated with cancer-specific survival. On multivariate analysis of these significant covariates, albumin (HR 4.77, 95% CI 1.35–16.85, P=0.015), locoregional treatment (HR 3.64, 95% CI 1.04–12.72, P=0.043) and systemic treatment (HR 2.29, 95% CI 1.23–4.27, P=0.009) were significant independent predictors of cancer-specific survival. Among tumour-based inflammatory factors, only tumour microvessel density (P<0.05) was independently associated with poorer cancer-specific survival. The host inflammatory responses are closely associated with poor tumour differentiation, proliferation and malignant disease progression in breast cancer

Building pathway clusters from Random Forests classification using class votes

<p>Abstract</p> <p>Background</p> <p>Recent years have seen the development of various pathway-based methods for the analysis of microarray gene expression data. These approaches have the potential to bring biological insights into microarray studies. A variety of methods have been proposed to construct networks using gene expression data. Because individual pathways do not act in isolation, it is important to understand how different pathways coordinate to perform cellular functions. However, there are no published methods describing how to build pathway clusters that are closely related to traits of interest.</p> <p>Results</p> <p>We propose to build pathway clusters from pathway-based classification methods. The proposed methods allow researchers to identify clusters of pathways sharing similar functions. These pathways may or may not share genes. As an illustration, our approach is applied to three human breast cancer microarray data sets. We found that our methods yielded consistent and interpretable results for these three data sets. We further investigated one of the pathway clusters found using PubMatrix. We found that informative genes in the pathway clusters do have more publications with keywords, like estrogen receptor, compared with informative genes in other top pathways. In addition, using the shortest path analysis in GeneGo's MetaCore and Human Protein Reference Database, we were able to identify the links which connect the pathways without shared genes within the pathway cluster.</p> <p>Conclusion</p> <p>Our proposed pathway clustering methods allow bioinformaticians and biologists to investigate how informative genes within pathways are related to each other and understand possible crosstalk between pathways in a cluster. Therefore, building pathway clusters may lead to a better understanding of molecular mechanisms affecting a trait of interest, and help generate further biological hypotheses from gene expression data.</p

Climate change as a social determinant of the quality of public health

In recent years, it has become recognized worldwide that the threats and consequences of climate change for public health and, thus, for the quality of human life, are very serious. The need to protect the planet from climate change is high on the international agenda of social problems. Climate change is currently the most serious environmental hazard, with negative effects on the entire ecosystem. The British Meteorological Office defines climate change as a large-scale, long-term shift in the planet’s weather patterns and average temperatures. Climate change can impact the essentials for human survival and health, such as air quality, water quality, and housing, and is often responsible for food insecurity and civil war. The incidence of communicable diseases and non-communicable diseases (NCDs), including mental illness, cardiovascular disease, chronic respiratory disease, cancer and diabetes mellitus, are on the rise. Ángel Guría, the Secretary General of the Organization for Economic Co-operation and Development (OECD) underlined “the need for swift global action on climate change”, adding that “climate change is a public health issue that is disproportionately affecting the most vulnerable, as well as those least responsible for climate change anthropogenic warming”. According to the World Health Organization (WHO), climate change is expected to cause around 250,000 additional deaths annually between 2030 and 2050; 38,000 of these will be due to exposure of the elderly to extremely high temperatures, 48,000 will be caused by diarrhea and 60,000 by malaria, while 95,000 children will die of malnutrition. Unfortunately, the Paris Agreement on Climate Change, which came into force on November 4, 2016, has hardly been activated. Conversely, in November 2019, US President Donald Trump announced that the US will denounce and withdraw completely from the Paris Agreement in November 2020. ©Athens Medical Society

Heat Shock Protein-27, -60 and -90 expression in gastric cancer: Association with clinicopathological variables and patient survival

Background: Heat shock proteins (HSPs) are ubiquitous, highly conserved proteins across all the species and play essential roles in maintaining protein stability within the cells under normal conditions, while preventing stress-induced cellular damage. HSPs were also overexpressed in various types of cancer, being associated with tumor cell proliferation, differentiation and apoptosis. The aim of the present study was to evaluate the clinical significance of HSP -27, -60, and -90 expression in gastric carcinoma. Methods: HSP -27, -60, and -90 proteins expression was assessed immunohistochemically in tumoral samples of 66 gastric adenocarcinoma patients and was statistically analyzed in relation to various clinicopathological characteristics, tumor proliferative capacity and patients&apos; survival. Results: HSP-27, -60, -90 proteins were abundantly expressed in gastric adenocarcinoma cases examined. HSP-27 expression was significantly associated with tumor size (pT, P = 0.026), the presence of organ metastases (pM, P = 0.046) and pStage (P = 0.041), while HSP-27 staining intensity with nodal status (pN, P = 0.042). HSP-60 expression was significantly associated with patients&apos; sex (P = 0.011), while HSP-60 staining intensity with patients&apos; age (P = 0.027) and tumor histopathological grade (P = 0.031). HSP-90 expression was not associated with any of the clinicopathological parameters examined; however, HSP-90 staining intensity was significantly associated with tumor size (pT, P = 0.020). High HSP-90 expression was significantly associated with longer overall survival times in univariate analysis (log-rank test, P = 0.033), being also identified as an independent prognostic factor in multivariate analysis (P = 0.026). Conclusion: HSP-27, -60, and -90 were associated with certain clinicopathological parameters which are crucial for the management of gastric adenocarcinoma patient. HSP-90 expression may also be an independent prognostic indicator in gastric adenocarcinoma patients. © 2009 Giaginis et al; licensee BioMed Central Ltd

Volterra-based nonlinear compensation in 400 Gb/s WDM multiband coherent optical OFDM systems

\u3cp\u3eWe apply a 3\u3csup\u3erd\u3c/sup\u3e-order inverse Volterra series nonlinear equalizer to a 400 Gb/s WDM multiband PM-16QAM OFDM signal. IVSTF-NLE provides a 0.6 dB Q-factor improvement and 1 dB nonlinear threshold increase compared to linear equalization.\u3c/p\u3

Coexistence of hepatocellular carcinoma (HCC) and c-Kit negative gastrointestinal stromal tumor (GIST): A case report

A past history of sporadic solid cancers is disclosed in 10% of gastrointestinal stromal tumor (GIST) patients. Simultaneous occurrence with other malignancies is encountered in 14 to 16%, but the synchronous occurrence of GIST and hepatocellular carcinoma (HCC) has been reported only once in the English literature. An 81-year-old male patient is presented with a preoperatively known HCC, in whom a synchronous small nodular omental GIST adjacent to the lesser curvature of the stomach was incidentally discovered. When a GIST is encountered, a thorough intraoperative investigation of the abdominal cavity currently remains the only reliable method for detection of a possible coexisting malignancy. © 2008 Southern Medical Association