Search results for " multiple"
showing 10 items of 903 documents
Anti-bacterial activity of graphene oxide as a new weapon nanomaterial to combat multidrug-resistance bacteria.
2016
Antibiotic resistance in microbial pathogens has become a serious health problem in the world. The increasing spread of hospital acquired infections especially in immunocompromised and cancer patients caused by multidrug-resistant (MDR) microbial pathogens is restricting the choices for impressive antibiotic therapy. So many efforts have been made to develop new compounds with antimicrobial activity. In recent years, nanoparticles, particularly graphene oxide (GO) nanoparticles have found many applications in various fields, including antibacterial action, pathogens bio detection, cancer therapy, and drug and gene delivery. The use of graphene oxide as an antibacterial agent for the treatme…
CMOS plasmonics in WDM data transmission: 200 Gb/s (8 × 25Gb/s) transmission over aluminum plasmonic waveguides
2018
We demonstrate wavelength-division-multiplexed (WDM) 200 Gb/s (8 × 25 Gb/s) data transmission over 100 μm long aluminum (Al) surface-plasmon-polariton (SPP) waveguides on a Si3N4 waveguide platform at telecom wavelengths. The Al SPP waveguide was evaluated in terms of signal integrity by performing bit-error-rate (BER) measurements that revealed error-free operation for all eight 25 Gb/s non-return-to-zero (NRZ) modulated data channels with power penalties not exceeding 0.2 dB at 10−9. To the best of our knowledge, this is the first demonstration of WDM enabled data transmission over complementary-metal-oxide-semiconductor (CMOS) SPP waveguides fueling future development of CMOS compatible …
Modulation of coaxial modal interferometers based on long period gratings in double cladding fibers
2009
This paper reports on the dynamic modulation of coaxial interferometers based on two cascaded long period gratings written in double cladding fibers. The interferometer is modulated by a piezoelectric ceramic which stretches one the gratings at tens of kHz, the output light is intensity modulated with an efficiency of 97 %. The device operates at 1530nm, has more than 50nm bandwidth, insertion loss of 0.4 dB and a temperature drift of 0.11 nm/ degrees C.
Resource allocation for OFDMA systems with multi-cell joint transmission
2012
This paper considers the downlink resource allocation of a coordinated multi-cell cluster in OFDMA systems with universal frequency reuse. Multi-cell joint transmission is considered via zero-forcing precoding. Furthermore, joint optimization of the user selection and power allocation across multiple subchannels and multiple cells is studied. The objective is to maximize the weighted sum rate under per-base-station power constraints. Based on general duality theory, two iterative resource allocation algorithms are proposed and compared with the optimal solution, which requires an exhaustive search of all possible combinations of users over all subchannels. Simulation results show that the t…
Power allocation optimization in OFDM-based cognitive radios based on sensing information
2011
Owing to the non-zero probability of the missed detection and false alarm of active primary transmission, a certain degree of performance degradation of the primary user (PU) from cognitive radio users (CRs) is unavoidable. In this paper, we consider OFDM-based communication systems and present efficient algorithms to maximize the total rate of the CR by optimizing jointly both the detection operation and the power allocation, taking into account the influence of the probabilities of missed detection and false alarm, namely, the sensing accuracy. The optimization problem can be formulated as a two-variable non-convex problem, which can be solved approximately by using an alternating directi…
Solving the Discrete Multiple Criteria Problem using Convex Cones
1984
An interactive method employing pairwise comparisons of attainable solutions is developed for solving the discrete, deterministic multiple criteria problem assuming a single decision maker who has an implicit quasi-concave increasing utility (or value) function. The method chooses an arbitrary set of positive multipliers to generate a proxy composite linear objective function which is then maximized over the set of solutions. The maximizing solution is compared with several solutions using pairwise judgments asked of the decision maker. Responses are used to eliminate alternatives using convex cones based on expressed preferences, and then a new set of weights is found that satisfies the i…
Energy-efficient resource allocation for OFDMA two-way relay networks with imperfect CSI
2015
Most of the existed works on the radio resource allocation (RRA) problem commonly assume the channel-state information (CSI) can be perfectly obtained by the transmission source. However, such assumption is not practical in the realistic wireless systems. In this work, we consider the practical implementation issues of resource allocation in orthogonal frequency division multiple access (OFDMA) two-way relay networks: the inaccuracy of channel-state information (CSI) available to the source. Instead, only the estimated channel status is known by the source. In this context, a joint optimization of subcarrier pairing and allocation, relay selection, and transmit power allocation is formulate…
A Watermarking of Medical Image : New Approach Based On "Multi-Layer" Method
2011
In order to contribute to security sharing and transmission of medical images, this paper propose a new approach for Watermarking image based on the techniques of Code Division Multiple Access (CDMA), Discrete Wavelet transform (DWT) and Error Correcting Code (ECC). The motivation of this approach is to improve the quantity of data integration with the conservation of the image visual quality. Therefore, this work permits to the user the capacity to correct the possible alterations if it exists. IRM and Echographic medical image are used to experiment this approach.
Polyclonal non multiresistant methicillin resistant Staphylococcus aureus isolates from clinical cases of infection occurring in Palermo, Italy, duri…
2012
Abstract Background The evolving epidemiology of methicillin resistant Staphylococcus aureus (MRSA) is characterized by the emergence of infections caused by non multiresistant MRSA carrying staphylococcal chromosomal cassette (SCC)mec IV or V in the healthcare settings. A molecular epidemiological analysis of non multiresistant MRSA isolates from four acute general hospitals was performed in Palermo, Italy, during a one year period. Methods For the purpose of the study, MRSA isolates were defined as non multiresistant when they were susceptible to at least three classes of non β-lactam antibiotics. Seventy-five isolates were submitted to antimicrobial susceptibility testing, multilocus seq…
New linezolid-like 1,2,4-oxadiazoles active against Gram-positive multiresistant pathogens
2013
The synthesis and the in vitro antibacterial activity of novel linezolid-like oxadiazoles are reported. Replacement of the linezolid morpholine C-ring with 1,2,4-oxadiazole results in an antibacterial activity against Staphylococcus aureus both methicillin-susceptible and methicillin-resistant comparable or even superior to that of linezolid. While acetamidomethyl or thioacetoamidomethyl moieties in the C(5) side-chain are required, fluorination of the phenyl B ring exhibits a slight effect on an antibacterial activity but its presence seems to reduce the compounds cytotoxicity. Molecular modeling performed using two different approaches - FLAP and Amber software - shows that in the binding…