Neural Computing and Applications - Computer-aided diagnosis system that uses classification process for an automated detection of breast cancer could provide a second opinion that improves... 相似文献
Electrolyte-Membrane-Insulator-Semiconductor (EMIS) sensors based on ZnO undoped and doped with a different molar ratio of Mg/Zn are demonstrated to detect calcium ions. The samples grown on the silicon substrates by the hydrothermal method were characterized to explore the impact of Mg content on the structural and compositional characteristics and sensing performance by X-ray diffraction analysis, field emission scanning electron microscopy, and X-ray photoelectron spectroscopy. The results indicated that the EIMS based on ZnO nanorods doped with 3% Mg had a high Ca2+ ion sensitivity (69 mV/decade) and linearity (99.8%). In addition, the samples have good stability with a low drift rate of 0.398 mV/h and possess great selectivity over other interference ions such as Na+, K+, Mg2+, and Ni2+ due to the employment of an ionophore membrane.
The antibacterial responses of zinc oxide (ZnO) structures against Staphylococcus aureus, Pseudomonas aeruginosa, and Streptococcus pyogenes were investigated. Two ZnO powder samples, one with rod-like (ZnO-1) and the other with plate-like (ZnO-2) structures, were characterized for their morphological, structural, and optical properties. The rods were 30–120 nm in diameter, and the plates were 40–100 nm thick. XRD results revealed the wurtzite crystallinity of ZnO with average crystallite sizes of 33.72 (ZnO-1) and 39.25 (ZnO-2) nm. ZnO-2 possessed a relatively higher green photoluminescence than that of ZnO-1, suggesting a relatively higher amount of oxygen vacancies in ZnO-2 structures. Optical density measurements showed that both ZnO samples inhibited the growth of S. aureus, P. aeruginosa, and S. pyogenes by 29–98% after 24 h of treatment. The most dramatic growth inhibition was observed in S. pyogenes with 96% and 98% inhibition for ZnO-1 and ZnO-2, respectively, leading to a probable bactericidal phenomenon. The toxicological effect on S. pyogenes was probably due to the absence of catalase, making the bacteria vulnerable to the harmful reactive oxygen species (ROS) released by ZnO. ZnO-1 induced higher inhibition toward S. aureus and P. aeruginosa than that of ZnO-2 because of the smaller particle size of rod structures compared to plate and slab structures. The adhesion of ZnO particles on the membrane of bacteria could be the underlying cause of zinc toxicity effect towards the bacteria. ZnO-1 possessed larger surface area and provided higher amount of zinc atom, thereby inducing higher level of toxicity toward the bacteria. Two possible mechanisms were proposed to explain the inhibition of bacteria, namely, ROS toxicity toward cellular constituents and interaction of zinc with bacteria membrane through adhesion of ZnO particle. Several ZnO morphological-antibacterial correlations were presented in this work. 相似文献
Neurotrophins, such as brain-derived neurotrophic factor (BDNF), are essential for neuronal survival and growth. The signaling cascades initiated by BDNF and its receptor are the key regulators of synaptic plasticity, which plays important role in learning and memory formation. Changes in BDNF levels and signaling pathways have been identified in several neurodegenerative diseases, including Alzheimer’s disease, Parkinson’s disease, and Huntington’s disease, and have been linked with the symptoms and course of these diseases. This review summarizes the current understanding of the role of BDNF in several neurodegenerative diseases, as well as the underlying molecular mechanism. The therapeutic potential of BDNF treatment is also discussed, in the hope of discovering new avenues for the treatment of neurodegenerative diseases. 相似文献
This paper discusses on the surface characteristics of each of the seven set-up process steps prior completion of under bump metallurgy (UBM) deposition. The Atomic Force Microscopy (AFM) and Scanning Electron Microscopy (SEM) techniques were used to obtain the surface roughness and morphology of each deposition process. The elemental analysis using Energy Disperse X-Ray (EDX) and precision micro-cross-section using Focus Ion Beam (FIB) was also used in this study. The first zincation process has high surface roughness but preserved surface morphology of initial thin-film surface. The second zincation provides the improved surface roughness due to the replacement aluminum layer with ion zinc in the solution. Smooth surfaces leads to better shear strength. However, second zincation will affect the Al thickness, hence excessive attacks on Al layer may cause reliability problem. 相似文献
The samples with nominal composition of Bi16Pb0.4Sr2Ca2?xEuxCu3Oy where x=0.000, 0.025, 0.050, 0.100, and 0.200 prepared by co-precipitation method (COP) have been investigated. They were characterized by X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM), electrical and resistivity measurement using the four-probe method. The temperature dependency on electrical resistance showed the superconducting behavior for all the samples. The critical current density (Jc) and superconductivity transition temperature (Tc?zero) of Eu substituted were found to be lower than those of the pure sample. Tc?zero varied between 100 and 73 K towards Eu concentration with the highest Tc?zero in the Eu substitution was found at 98 K for x=0.025 and decreased gradually for further substitution of Eu corresponding to a small change in the carrier concentration. Jc decreased with increasing Eu substitution, and it was measured to be at 5.7512 A/cm2 in the Eu free sample and at 2.1223 A/cm2 for the x=0.025 sample at 77 K. XRD analyses showed the decrease of the volume fraction of Bi-2223/Bi-2212 (%) which were estimated from 78.13/21.87 for x=0.000 to 23.18/76.82 for x=0.200. The crystallographic structure was found to change slightly from tetragonal to orthorhombic in Eu substituted samples. The lattice parameter c of the Eu samples decreased due to the incorporation of Eu3+ (0.95 Å) with smaller ionic size at the Ca2+ (0.99 Å) site. From the SEM investigation, the grain connectivity became weak and the porosity increased with the increment of Eu concentration, resulting in the decrease of Jc. 相似文献
The comparison between YBa2Cu3?xCaxOδ and YBa2Cu4?xCaxO8 superconductors substituted with Ca at the Cu-site was investigated. The concentration of Ca varied from x=0.00 to x=0.15. Resistivity and current density measurement (without magnetic field) were measured using four-probe method. The samples were characterized using X-Ray Diffraction (XRD) and Field Emission Scanning Electron Microscopy (FESEM). From the resistivity measurement, the critical temperature (Tc?zero) in x=0.00 was 84 K for Y-123 and 83 K for Y-124 superconductor system. As the Ca concentration increased to x=0.15, both superconductor systems showed a decrease in value whereby 71 K for Y-123 and 74 K for Y-124. This was a result of the decrease in the hole concentration. Critical current density (Jc) decreased with the further increment of Ca concentration owing to grain connectivity and an increase of porosity. At 50 K, Jc decreased from 3.9790 A/cm2 at x=0.00 to 3.5184 A/cm2 at x=0.15 for Y-123, and from 3.6209 A/cm2 at x=0.00 to 0.5243 A/cm2 at x=0.15 for Y-124. The crystallographic crystal structure showed that both Y-123 and Y-124 superconductor systems exhibited an orthorhombic form. FESEM microscopy showed that the Y-123 sample had less porosity compared to Y-124 samples and the resulting Y-123 sample had a higher Jc compared to the Y-124 sample. 相似文献