Slab Waveguide Sensor with Left-handed Material Core Layer for Detection an Adlayer Thickness and Index

A four-layer slab waveguide structure with a lossy left-handed material (LHM) core layer is investigated as a surface sensor for detection any change in an adlayer thickness and refractive index. The sensitivities of the effective refractive index to any change in the refractive index/thickness of the adlayer are derived and studied with the parameters of the LHM. It is found that a slight change in the real parts of the permittivity and permeability of the LHM can significantly improve the sensitivity of the proposed sensor

Dispersion properties of anisotropic-metamaterial slab waveguide structure

The dispersion properties of guided waves in an anisotropic film sandwiched between a left-handedmaterial (LHM) and a dielectric are investigated in this work. Detailed mathematical derivationof the dispersion relation is presented. Both the anisotropic guiding layer and the LHM are assumedto be dispersive. Many interesting features have been found. The dispersion properties exhibita slight dependence on the parameters of the anisotropic guiding layer whereas they showa significant change with any perturbation in some of the LHM layer parameters, especially forω>5.2GHz.The dispersion properties of guided waves in an anisotropic film sandwiched between a left-handedmaterial (LHM) and a dielectric are investigated in this work. Detailed mathematical derivationof the dispersion relation is presented. Both the anisotropic guiding layer and the LHM are assumedto be dispersive. Many interesting features have been found. The dispersion properties exhibita slight dependence on the parameters of the anisotropic guiding layer whereas they showa significant change with any perturbation in some of the LHM layer parameters, especially forω>5.2GHz

Dispersion properties of slab waveguides with double negative material guiding layer and nonlinear substrate

The dispersion properties of transverse electric nonlinear waves in a three-layer slab waveguide which consists of a double negative material (DNM) guiding layer sandwiched between an intensity-dependent refractive index substrate and semi-infinite linear dielectric cover are investigated. The dispersion properties for self-focusing and self-defocusing substrate nonlinearity are presented. The effects of the negative parameters of the DNM on the dispersion characteristics are investigated

Breast-cancer detection using blood-based infrared molecular fingerprints

BACKGROUND Breast cancer screening is currently predominantly based on mammography, tainted with the occurrence of both false positivity and false negativity, urging for innovative strategies, as effective detection of early-stage breast cancer bears the potential to reduce mortality. Here we report the results of a prospective pilot study on breast cancer detection using blood plasma analyzed by Fourier-transform infrared (FTIR) spectroscopy - a rapid, cost-effective technique with minimal sample volume requirements and potential to aid biomedical diagnostics. FTIR has the capacity to probe health phenotypes via the investigation of the full repertoire of molecular species within a sample at once, within a single measurement in a high-throughput manner. In this study, we take advantage of cross-molecular fingerprinting to probe for breast cancer detection. METHODS We compare two groups: 26 patients diagnosed with breast cancer to a same-sized group of age-matched healthy, asymptomatic female participants. Training with support-vector machines (SVM), we derive classification models that we test in a repeated 10-fold cross-validation over 10 times. In addition, we investigate spectral information responsible for BC identification using statistical significance testing. RESULTS Our models to detect breast cancer achieve an average overall performance of 0.79 in terms of area under the curve (AUC) of the receiver operating characteristic (ROC). In addition, we uncover a relationship between the effect size of the measured infrared fingerprints and the tumor progression. CONCLUSION This pilot study provides the foundation for further extending and evaluating blood-based infrared probing approach as a possible cross-molecular fingerprinting modality to tackle breast cancer detection and thus possibly contribute to the future of cancer screening

Exposure assessment of radon in the drinking water supplies: a descriptive study in Palestine

<p>Abstract</p> <p>Background</p> <p>Radon gas is considered as a main risk factor for lung cancer and found naturally in rock, soil, and water. The objective of this study was to determine the radon level in the drinking water sources in Nablus city in order to set up a sound policy on water management in Palestine.</p> <p>Methods</p> <p>This was a descriptive study carried out in two phases with a random sampling technique in the second phase. Primarily, samples were taken from 4 wells and 5 springs that supplied Nablus city residents. For each source, 3 samples were taken and each was analyzed in 4 cycles by RAD 7 device manufactured by Durridge Company. Secondly, from the seven regions of the Nablus city, three samples were taken from the residential tap water of each region. Regarding the old city, ten samples were taken. Finally, the mean radon concentration value for each source was calculated.</p> <p>Results</p> <p>The mean (range) concentration of radon in the main sources were 6.9 (1.5-23.4) Becquerel/liter (Bq/L). Separately, springs and wells' means were 4.6 Bq/L and 9.5 Bq/L; respectively. For the residential tap water in the 7 regions, the results of the mean (range) concentration values were found to be 1.0 (0.9-1.3) Bq/L. For the old city, the mean (range) concentration values were 2.3 (0.9-3.9) Bq/L.</p> <p>Conclusions</p> <p>Except for Al-Badan well, radon concentrations in the wells and springs were below the United State Environmental Protection Agency maximum contaminated level (U.S EPA MCL). The level was much lower for tap water. Although the concentration of radon in the tap water of old city were below the MCL, it was higher than other regions in the city. Preventive measures and population awareness on radon's exposure are recommended.</p

Optimization of transverse electric peak-type metal-clad waveguide sensor using double-negative materials

In a very recent work, a transverse electric peak-type metal-clad waveguide optical sensor was proposed in which a double-negative material (DNM) was used as a guiding layer. The sensor was found to exhibit a considerable angular shift of the reflectance peak for small changes in the refractive index of the analyte, due to the DNM layer. In this work, the optimization of the structure parameters is investigated to find out the most appropriate metal and its optimal thickness. Moreover, the optimal DNM layer parameters corresponding to the highest sensitivity are explored. Our calculations reveal that metals with high absolute value of the real part of the permittivity correspond to sharper peaks. Moreover, as the absolute value of the real part of both ε and μ of the DNM increases, the reflectance peak becomes sharper and the dip following the peak becomes deeper

Transverse magnetic peak type metal-clad optical waveguide sensor

Transverse magnetic (TM) waves in a four-layer slab waveguide structure are studied for optical sensing applications. The structure consists of a semi-infinite substrate, a thin metal layer, a medium with negative permittivity and permeability as a guiding layer, and a semi-infinite layer as a cover. The proposed sensor is operated in reflection mode in which the angular position of the reflectance peak is used to detect small changes in the refractive index of the cover medium. The optimal structure parameters that correspond to the sharpest and highest peak are presented. The results reveal that for aluminum metal layer, a thickness of about 9 nm represents the optimum metal thickness. Moreover, the thickness, negative permittivity, and negative permeability of the guiding layer are found to have great impacts on the performance of the proposed optical waveguide sensor

Peak type metal-clad waveguide sensor using negative index materials

A four-layer metal-clad structure was considered as an optical sensor for refractometry applications. The structure had a negative index material (NIM) as a core layer. The structure parameters were chosen for so that the reflectance profile of the proposed structure shows a sharp peak, which is appropriate for sensing applications. The sensor was found to exhibit a considerable angular shift of the reflectance peak for small changes in the refractive index of the analyte, due to the NIM layer

Slab waveguide sensor utilizing left-handed material core and substrate layers

Propagation of transverse electric (TE) polarized light in two three-layer slab waveguide structures comprising left-handed materials (LHMs) is studied for sensing applications. The LHM layer occupies the core layer in the first structure and the substrate layer in the second structure. The sensitivity of the effective refractive index of the guided mode to any change in the index of an analyte medium located in the cladding region is derived and studied. The optimal structure parameters corresponding to the highest sensitivity are found. The results reveal that the sensitivity of the second structure with LHM substrate is much higher than that of the first with LHM core layer. The sensitivity can reach up to 70% for the LHM substrate structure for some waveguide configurations whereas it can reach up to 45.5% for the LHM core structure. The sensitivities of the two structures are found to be significantly high when compared