Minimization of the receiver cost in an all-optical ring with a limited number of wavelengths

A new all-optical node architecture, known as \emph{Packet Optical Add-Drop Multiplexer} (POADM), may lead to a considerable cost reduction for the infrastructure of the all-optical metropolitan rings if associated with proper dimensioning studies. We present a dimensioning problem which consists of minimizing the total number of receivers located in POADMs for a metropolitan all-optical ring with a fixed number of wavelengths and a given traffic matrix. We prove that this problem is NP-complete and provide a heuristic. The heuristic principle is to match and to group transmissions instead of considering them independently. We justify the transmission group matching approach by confronting the results of our algorithm with its simplified version. The results obtained allow us to recommend the heuristic in the planning of POADM configurations in all-optical rings with a limited number of wavelengths

FT-IR Microspectrometry Reveals the Variation of Membrane Polarizability due to Epigenomic Effect on Epithelial Ovarian Cancer

Ovarian cancer, as well as other cancers, is primarily caused by methylation at cytosines in CpG islands, but the current marker for ovarian cancer is low in sensitivity and failed in early-stage detection. Fourier transform infrared (FT-IR) spectroscopy is powerful in analysis of functional groups within molecules, and infrared microscopy illustrates the location of specific groups within single cells. In this study, we applied HPLC and FT-IR microspectrometry to study normal epithelial ovarian cell line immortalized ovarian surface epithelium (IOSE), two epithelial ovarian cell lines (A2780 and CP70) with distinct properties, and the effect of a cancer drug 5-aza-2\u27-deoxycytidine (5-aza) without labeling. Our results reveal that inhibition of methylation on cytosine with 5-aza initiates the protein expression. Furthermore, paraffin-adsorption kinetic study allows us to distinguish hypermethylated and hypomethyated cells, and this assay can be a potential diagnosis method for cancer screening

A Cu/Polypyrrole-Coated Stainless Steel Mesh Membrane Cathode for Highly Efficient Electrocoagulation-Coupling Anti-Fouling Membrane Filtration

Membrane filtration fouling has become a significant issue that restricts its wide application. The electrocoagulation (EC) technique combines a variety of synergistic pollutant removal technologies (including flocculation, redox, and air flotation), which can be an ideal pretreatment process for membrane filtration. In this work, a novel Cu2+-doped and polypyrrole-coated stainless steel mesh membrane (Cu/PPy–SSM) was prepared by direct current electrodeposition, and it was introduced in an electrocoagulation-membrane reactor (ECMR) to construct an EC–membrane filtration coupling system. The Cu/PPy–SSM was applied as the cathode, while an aluminum plate was used as the anode in the ECMR. The ECMR enabled an excellent humic acid (HA) removal performance and could effectively mitigate the fouling of the Cu/PPy–SSM. Its performance can be attributed to the following: (1) the Cu/PPy–SSM can repel the negatively charged pollutants under the applied electric field; (2) the cathodic hydrogen gas produced on the Cu/PPy–SSM restrains the compacting of the cake layer and delays degradation of membrane flux; and (3) the resultant porous loose structure can perform as a dynamic membrane, which can effectively promote the separation performance of the Cu/PPy–SSM. The resultant ECMR enabled an improved HA removal rate of 92.77%, and the membrane-specific flux could be stabilized at more than 86%. Response surface methodology (RSM) was used to optimize the operation parameters of the ECMR, and the predicted HA removal rate reached 93.01%. Both the experimental results and modelled predictions show that using the Cu/PPy–SSM as a cathode can lead to excellent performance of the ECMR