Robust Automated Tumour Segmentation on Histological and Immunohistochemical Tissue Images

Tissue microarray (TMA) is a high throughput analysis tool to identify new diagnostic and prognostic markers in human cancers. However, standard automated method in tumour detection on both routine histochemical and immunohistochemistry (IHC) images is under developed. This paper presents a robust automated tumour cell segmentation model which can be applied to both routine histochemical tissue slides and IHC slides and deal with finer pixel-based segmentation in comparison with blob or area based segmentation by existing approaches. The presented technique greatly improves the process of TMA construction and plays an important role in automated IHC quantification in biomarker analysis where excluding stroma areas is critical. With the finest pixel-based evaluation (instead of area-based or object-based), the experimental results show that the proposed method is able to achieve 80% accuracy and 78% accuracy in two different types of pathological virtual slides, i.e., routine histochemical H&E and IHC images, respectively. The presented technique greatly reduces labor-intensive workloads for pathologists and highly speeds up the process of TMA construction and provides a possibility for fully automated IHC quantification

Automatic Tumor-Stroma Separation in Fluorescence TMAs Enables the Quantitative High-Throughput Analysis of Multiple Cancer Biomarkers

The upcoming quantification and automation in biomarker based histological tumor evaluation will require computational methods capable of automatically identifying tumor areas and differentiating them from the stroma. As no single generally applicable tumor biomarker is available, pathology routinely uses morphological criteria as a spatial reference system. We here present and evaluate a method capable of performing the classification in immunofluorescence histological slides solely using a DAPI background stain. Due to the restriction to a single color channel this is inherently challenging. We formed cell graphs based on the topological distribution of the tissue cell nuclei and extracted the corresponding graph features. By using topological, morphological and intensity based features we could systematically quantify and compare the discrimination capability individual features contribute to the overall algorithm. We here show that when classifying fluorescence tissue slides in the DAPI channel, morphological and intensity based features clearly outpace topological ones which have been used exclusively in related previous approaches. We assembled the 15 best features to train a support vector machine based on Keratin stained tumor areas. On a test set of TMAs with 210 cores of triple negative breast cancers our classifier was able to distinguish between tumor and stroma tissue with a total overall accuracy of 88%. Our method yields first results on the discrimination capability of features groups which is essential for an automated tumor diagnostics. Also, it provides an objective spatial reference system for the multiplex analysis of biomarkers in fluorescence immunohistochemistry

Deposition of ZnO thin films by RF&DC magnetron sputtering on silicon and porous-silicon substrates for pyroelectric applications

In this study, the temperature response of ZnO thin film is investigated in an attempt to enhance its pyroelectric performance. The film is formed on PS and Si substrates utilizing RF&DC magnetron sputtering deposition technique. The outcome of study reveals a pyroelectric coefficient observed from ZnO film on PS which is 40 times higher than that on Si and a pyroelectric voltage as high as 2.4 V due to PS's profound effect on film formation, large surface to volume area and low thermal conductivity. Thus, this study can lead the way to a robust, reliable and more efficient pyroelectric operation of ZnO with employment of PS structure. © 2017 Elsevier B.V

A Comparative Study of Fabrication of Long Wavelength Diode Lasers Using CCl 2 F 2 /O 2 and H 2 /CH 4

ABSTRACT We report comparatively on fabrication of two-section ridge-waveguide tapered 3 quantum well (QW) InGaAsP/InP (1300 nm) and 5 QW AlGaInAs/InP (1550 nm) diode lasers. Gas mixtures of CCl 2 F 2 /O 2 and H 2 /CH 4 were used to form ridge-waveguide on the lasers with InP-based material structures. As known, chlorine-and hydro-carbon based gases are used to fabricate ridge-waveguide structures. Here, we show the difference between the structures obtained by using the both gas mixtures in which surface and sidewall structures as well as performance of the lasers were analysed using scanning electron microscopy. It is demonstrated that gas mixtures of CCl 2 F 2 /O 2 highly deteriorated the etched structures although different flow rates, rf powers and base pressures were tried. We also show that the structures etched with H 2 /CH 4 gas mixtures produced much better results that led to the successful fabrication of two-section devices with ridge-waveguide. The lasers fabricated using H 2 /CH 4 were characterized using output power-current (P-I) and spectral results

Reference-plane-invariant and thickness- and branch-index-independent retrieval of effective parameters of bi-anisotropic metamaterials

We propose a retrieval method for reference-plane-invariant electromagnetic parameter measurements of bi-anisotropic metamaterial slabs without resorting to accurate information of the slab thickness and the branch index. To extract reference-plane distances, the slab thickness, and the branch index, we first approximate wave impedances and refractive index away from the slab resonance frequency and then use scattering parameters to calculate the refractive index and the branch index. Once these quantities are determined, they are used as inputs for the retrieval of electromagnetic properties of slabs over the whole band. Different approximations for refractive index and wave impedances are applied to demonstrate the applicability and accuracy of our proposed method. We tested our method for electromagnetic parameter extraction of bi-anisotropic split-ring-resonator and Omega-shaped MM slabs with different number of unit cells. From our analysis, we note that inaccurate information of reference-plane distances, the slab length, and the branch index not only changes the amplitude but also shifts the response of the electromagnetic properties. We show that the presented method can be applied for accurate electromagnetic parameter extraction of bi-anisotropic MM slabs

Investigation of transmitted, reflected, and absorbed powers of periodic and aperiodic multilayered structures composed of bi-anisotropic metamaterial slab and conventional material

In this study, we investigate transmitted, reflected, and absorbed powers in forward and backward directions of periodic and aperiodic multilayered structures composed of bi-anisotropic metamaterial (MM) slab and conventional material. Aperiodic multilayered structure is realized by a change in thickness of any bi-anisotropic MM slab or of any conventional material. From this analysis, we note the following key results. First, identical (non-identical) forward and backward transmitted (reflected and absorbed) powers are observed for the analyzed periodic and aperiodic multilayered structures due to reciprocity (reflection-asymmetry) of bi-anisotropic MM slabs. Second, thickness-resonance phenomenon of conventional materials produces some peaks in the transmitted powers of periodic multilayered structures aside from the resonance frequency region of bi-anisotropic MM slabs. Third, each thickness-resonance frequency splits into many frequencies upon increasing the number of sections of periodic multilayered structures (no splitting when number of periods is one). Fourth, while the effect of changing the thickness of any bi-anisotropic MM slab within the aperiodic multilayered structure has no considerable effect around the resonance region of bi-anisotropic MM slabs (resonance of resonating structures such as MM slabs does not change with thickness), the same change in thickness of the conventional material drastically alters forward/backward reflected and absorbed powers aside from the resonance region of bi-anisotropic MM slabs (thickness-resonance totally depends on the value of thickness of conventional materials). The outcomes presented here can be particularly useful for propagation-related applications requiring cascade connection of various MM slabs. © 2014 Elsevier B.V. All rights reserved

Presence of sialic acid in prothoracic glands of Galleria mellonella (Lepidoptera)

The presence of sialic acid (SA) in prothoracic glands (PGs) of Galleria mellonella was determined by the methods of electron microscopy (EM), histochemistry, spectrophotometry (SP) and electronic ionization (EI)-mass spectroscopy. Histochemical observations were carried out by the cationic dye ruthenium red (RR), staining with and without neuraminidase digestion in the larval stage. Neuraminidase-sensitive SA was demonstrated by the decrease in the amount of RR-binding following neuraminidase digestion. The total amount of SA was found to be 0.09016 mg g-1 in dry tissue by spectrophotometric determination. EI-mass spectroscopy results confirmed the EM and SP observations. The fragmentation scheme derived from EI-mass analysis exhibited the presence of the lactonized form of Neu5Gc7, 9Ac2. On the basis of the various pieces of evidence described above, it was firmly concluded that Neu5Gc7, 9Ac2 molecules were present in PGs of G. mellonella.1181Gratefully dedicated to retired Prof. S. Geldiay. The authors want to thank TOBITAK for partial financial Support (grant No. 1181) and for running the EI-mass spectra. -

Reference-Plane-Invariant Effective Thickness and Electromagnetic Property Determination of Isotropic Metamaterials Involving Boundary Effects

It is well recognized that near-field effects become dominant when the metamaterial (MM) is in resonance. In addition, any inaccurate information of the location of reference planes, and the effective length can seriously affect the accuracy of retrieved electromagnetic properties of MMs. By considering all these issues, in this research paper, we propose a retrieval method for reference-plane invariant and thickness-independent determination of electromagnetic parameters of MM slabs involving boundary effects. Our method first accomplishes determination of effective length of MMs and calibration-plane factors using scattering parameter measurements, aside the resonance region, of two identical MMs with different lengths. Our method then incorporates near-field effects in accurate retrieval of electromagnetic properties of MMs. The method is verified by scattering parameters simulated for a homogeneous conventional material and a weakly or negligibly coupled inhomogeneous MM slab made by two metallic concentric split-ring-resonators. Consequences of an inaccurate information of reference-plane transformation factors and the value of effective lengths and of noninclusion of near field effects on the retrieved electromagnetic properties are thoroughly discussed by way of few examples to substantiate the accuracy of the proposed method. © 1995-2012 IEEE