Automated image classification of chest X-rays of COVID-19 using deep transfer learning.

INTRODUCTION: In December 2019, the city of Wuhan, located in the Hubei province of China became the epicentre of an outbreak of a pandemic called COVID-19 by the World Health Organisation. The detection of this virus by rRTPCR (Real-Time Reverse Transcription-Polymerase Chain Reaction) tests reported high false negative rate. The manifestations of CXR (Chest X-Ray) images contained salient features of the virus. The objective of this paper is to establish the application of an early automated screening model that uses low computational power coupled with raw radiology images to assist the physicians and radiologists in the early detection and isolation of potential positive COVID-19 patients, to stop the rapid spread of the virus in vulnerable countries with limited hospital capacities and low doctor to patient ratio in order to prevent the escalating death rates. MATERIALS AND METHODS: Our database consists of 447 and 447 CXR images of COVID-19 and Nofindings respectively, a total of 894 CXR images. They were then divided into 4 parts namely training, validation, testing and local/Aligarh dataset. The 4th (local/Aligarh) folder of the dataset was created to retest the diagnostics efficacy of our model on a developing nation such as India (Images from J.N.M.C., Aligarh, Uttar Pradesh, India). We used an Artificial Intelligence technique called CNN (Convolutional Neural Network). The architecture based on CNN used was MobileNet. MobileNet makes it faster than the ordinary convolutional model, while substantially decreasing the computational cost. RESULTS: The experimental results of our model show an accuracy of 96.33%. The F1-score is 93% and 96% for the 1st testing and 2nd testing (local/Aligarh) datasets (Tables 3.3 and 3.4). The false negative (FN) value, for the validation dataset is 6 (Fig. 3.6), for the testing dataset is 0 (Fig. 3.7) and that for the local/Aligarh dataset is 2 . The recall/sensitivity of the classifier is 93% and 96% for the 1st testing and 2nd testing (local/Aligarh) datasets (Tables 3.3 and 3.4). The recall/sensitivity for the detection of specifically COVID-19 (+) for the testing dataset is 88% and for the locally acquired dataset from India is 100%. The False Negative Rate (FNR) is 12% for the testing dataset and 0% for the locally acquired dataset (local/Aligarh). The execution time for the model to predict the input images and classify them is less than 0.1 s. DISCUSSION AND CONCLUSION: The false negative rate is much lower than the standard rRT-PCR tests and even 0% on the locally acquired dataset. This suggests that the established model with end-to-end structure and deep learning technique can be employed to assist radiologists in validating their initial screenings of Chest X-Ray images of COVID-19 in developed and developing nations. Further research is needed to test the model to make it more robust, employ it on multiclass classification and also try sensitise it to identify new strains of COVID-19. This model might help cultivate tele-radiology.

Green Synthesis of CeO2 Nanoparticles from the Abelmoschus esculentus Extract: Evaluation of Antioxidant, Anticancer, Antibacterial, and Wound-Healing Activities.

Metal oxide nanoparticles synthesized by the biological method represent the most recent research in nanotechnology. This study reports the rapid and ecofriendly approach for the synthesis of CeO2 nanoparticles mediated using the Abelmoschus esculentus extract. The medicinal plant extract acts as both a reducing and stabilizing agent. The characterization of CeO2 NPs was performed by scanning electron microscopy (SEM), X-ray diffraction (XRD), ultraviolet-visible spectroscopy (UV-Vis), and Fourier transform infrared spectroscopy (FTIR). The in vitro cytotoxicity of green synthesized CeO2 was assessed against cervical cancerous cells (HeLa). The exposure of CeO2 to HeLa cells at 10-125 µg/mL caused a loss in cellular viability against cervical cancerous cells in a dose-dependent manner. The antibacterial activity of the CeO2 was assessed against S. aureus and K. pneumonia. A significant improvement in wound-healing progression was observed when cerium oxide nanoparticles were incorporated into the chitosan hydrogel membrane as a wound dressing.

Mathematical modeling and experimental analysis of the efficacy of photodynamic therapy in conjunction with photo thermal therapy and PEG-coated Au-doped TiO2 nanostructures to target MCF-7 cancerous cells.

Some nanoscale morphologies of titanium oxide nanostructures blend with gold nanoparticles and act as satellites and targeted weapon methodologies in biomedical applications. Simultaneously, titanium oxide can play an important role when combined with gold after blending with polyethylene glycol (PEG). Our experimental approach is novel with respect to the plasmonic role of metal nanoparticles as an efficient PDT drug. The current experimental strategy floats the comprehensive and facile way of experimental strategy on the critical influence that titanium with gold nanoparticles used as novel photosensitizing agents after significant biodistribution of proposed nanostructures toward targeted site. In addition, different morphologies of PEG-coated Au-doped titanium nanostructures were shown to provide various therapeutic effects due to a wide range of electromagnetic field development. This confirms a significantly amplified population of hot electron generation adjacent to the interface between Au and TiO2 nanostructures, leading to maximum cancerous cell injury in the MCF-7 cell line. The experimental results were confirmed by applying a least squares fit math model which verified our results with 99% goodness of fit. These results can pave the way for comprehensive rational designs for satisfactory response of performance phototherapeutic model mechanisms along with new horizons of photothermal therapy (HET) and photodynamic therapy (HET) operating under visible and near-infrared (NIR) light.

Manganese-doped cerium oxide nanocomposite as a therapeutic agent for MCF-7 adenocarcinoma cell line.

The preparation of a manganese-doped cerium oxide (Mn:CeO2) nanocomposite via hydrothermal route is described. Cubic fluorite structure of single phase was exhibited by studying structural analysis through x-ray diffraction (XRD) technique and morphological analysis was conducted by scanning electron microscope. Surface analytic technique of energy dispersive x-ray spectroscopy (EDX) was conducted to analyze the relative amount of any impurity and doping. Structural changes due to manganese doping such as increment in production of vacancies of oxygen within crystal of cerium oxide, and reduction in size of crystallite and constant of lattice was observed in our research study. Moreover, the Mn:CeO2 nanocomposite demonstrates differential cytotoxicity against MCF-7 adenocarcinoma cell line, which renders it a promising candidate for targeted cancer therapy. The anti-tumorous activity of the cerium oxide nanocomposite was significantly enhanced with doping of manganese, which is directly linked with the generation of highly reactive oxygen facets. The experimental results are supported by a mathematical model that confirms a confidence level of 95%. This research has paved the way for many utilities in therapeutics and magnetic resonance imaging diagnostics through new observations, and hence verified their math model.

Delving into the properties of polymer nanocomposites with distinctive nano-particle quantities, for the enhancement of optoelectronic devices.

The study focusses on synthesis and modification of structural, optical and electrical characteristics of nanostructured titanium dioxide anatase embedded Poly(methyl methacrylate) (PMMA) nanocomposite with different weight percentages (0.03, 0.06, 0.12, 0.18 and 0.24%) by the solvent casting method. Modification in the morphology of PMMA nanocomposites with an increasing amount of titanium dioxide anatase is studied by using a field emission scanning electron microscope (FE-SEM). Micrograms of FE-SEM show spherical shaped nanoparticles distribution in PMMA nanocomposites thin films. In optical characterization, transmission, optical band gaps, the real and imaginary part of dielectric constant, linear susceptibility, optical conductivity, refractive index and extinction coefficient are calculated using experimental data. It is observed that the optical band gap has an overall decreasing trend with increasing the weight percentage of TiO2 (anatase) in PMMA nanocomposites. It is also found that values of all electrical parameters decrease with increasing the weight percentage of TiO2 (anatase) in PMMA nanocomposites. All wavelength depending parameters are investigated in the wavelength range from 190 nm to 2700 nm. Single oscillator model is used to analyze the refractive index dispersion and estimation of the oscillator energy and dispersion energy of the films. The study is applicable to optical sensors and other optoelectronic devices.

Improving Photophysical Properties of White Emitting Ternary Conjugated Polymer Blend Thin Film via Additions of TiO2 Nanoparticles.

The effect of TiO2 nanoparticles on the photophysical properties of ternary conjugated polymer (CP) blends of poly(9,9-dioctylfluorene-2,7-diyl) (PFO), poly 9,9-dioctylfluorene-alt-benzothiadiazole (F8BT) and poly(2-methoxy-5(2-ethylhexyl)-1,4 -phenylenevinylene (MEH-PPV) thin films was investigated. This ternary blend used a fixed amount of PFO as the donor with MEH-PPV and F8BT in various ratios as the acceptors. The solution-blending method and the spin-coating technique were used to prepare the blends and the thin films, respectively. Through efficient Förster Resonance Energy Transfer (FRET), the desired white emission was achieved with PFO/0.3 wt.% F8BT/0.5 wt.% MEH-PPV ternary blend thin film. Additions of nanoparticles up to 10 wt.% dramatically intensified the white emission which then dimmed at higher contents due to agglomerations. The current density-voltage characteristics of the nanocomposite thin films exhibited dependency on the content and distributions of the nanoparticles. Finally, a possible underlying mechanism for the intensification of emission is proposed.

Bandgap Tuning and Blue-Green Band Emissions of Sol-Gel Synthesized ZnO Films by High Cu Doping.

The present research focuses on the preparation of ZnO thin films both undoped and doped with varying Cu concentrations (0.0%, 0.8%, 3.0%, 5.0%, 10.0% and 20.0%) using sol-gel spin coating technique. The optical bandgap (Eg) for undoped films is recorded as 3.239 eV and shows a little increase to 3.248 eV when it is doped with 0.8% Cu concentration whereas further increase of Cu doping concentration, it is decreased from 3.248 eV to 3.107 eV for 20% Cu. The EU (Urbach Energy) is improved with the enhancement of Cu doping concentration. Ultraviolet (UV) and bluegreen band emissions are noticed from PL (photoluminescence) spectra. The UV peak intensities are diminished with increasing Cu doping concentration while the blue peaks intensities are amplified. These results illustrate that ZnO films doped with Cu meet the requirement for applications in different blue emission devices.

Effect of ZnO Nanoparticles Coating Layers on Top of ZnO Nanowires for Morphological, Optical, and Photovoltaic Properties of Dye-Sensitized Solar Cells.

This paper reports on the synthesis of ZnO nanowires (NWs), as well asthe compound nanostructures of nanoparticles (NPs) and nanowires (NWs+NPs) with different coating layers of NPs on the top of NWs and their integration in dye-sensitized solar cells (DSSCs). In compound nanostructures, NWs offer direct electrical pathways for fast electron transfer, and the NPs of ZnOdispread and fill the interstices between the NWs of ZnO, offering a huge surface area for enough dye anchoring and promoting light harvesting. A significant photocurrent density of 2.64 mA/cm2 and energy conversion efficiency of 1.43% was obtained with NWs-based DSSCs. The total solar-to-electric energy conversion efficiency of the NWs+a single layer of NPs was found to be 2.28%, with a short-circuit photocurrent density (JSC) of 3.02 mA/cm2, open-circuit voltage (VOC) of 0.74 V, and a fill factor (FF) of 0.76, which is 60% higher than that of NWs cells and over 165% higher than NWs+a triple layer of NPs-based DSSCs. The improved performance was obtained due to the increased specific surface area for higher dye anchoring and light harvesting of compound nanostructures with NWs+a single layer of NPs.

Manganese-Doped Cerium Oxide Nanocomposite Induced Photodynamic Therapy in MCF-7 Cancer Cells and Antibacterial Activity.

In this experimental approach, we explored the structures, morphologies, phototoxicities, and antibacterial activities of undoped and Mn-doped ceria nanocomposite materials, Mn x Ce1-x O2. The Mn x Ce1-x O2 nanocomposites were synthesized by employing a soft chemical route. Our prime focus was on the influence of different factors, both physical and chemical, i.e., the concentration of manganese in the product, size of the nanocomposite, drug dose, and incubation time, on the bacterial strains. Different bacterial strains were selected as experimental biological models of the antibacterial activity of the manganese-doped cerium oxide nanocomposite. In addition to the photodynamic response, the adenocarcinoma cell line (MCF-7) was also studied. Based on cell viability losses and bacterial inhibition analyses, the precise mechanisms of apoptosis or necrosis of 5-ALA/PpIX-exposed MCF-7 cells under 630 nm red lights and under dark conditions were elucidated. It was observed that the undoped nanocomposites had lower cytotoxicities and inhibitions compared with those of the doped nanocomposites towards pathogens. The antibacterial activity and effectiveness for photodynamic therapy were enhanced in the presence of the manganese-doped ceria nanocomposite, which could be attributed to the correlation of the maximum reactive oxygen species generation for targeted toxicity and maximum antioxidant property in bacteria growth inhibition. The optimized cell viability dose and doping concentration will be beneficial for treating cancer and bacterial infections in the future.

Investigating the coumarin capability in chalcogenide 20TI2Se-80Pr2Se3 system based photovoltaics.

Chalcogenide films containing various contents of coumarin (CO) are deposited on the p-type Si substrates. Al/coumarin doped chalcogenide films/p-Si contact exhibits a rectifying behavior. The electrical and photoresponse properties of the prepared diodes are characterized by current and capacitance measurements under various illumination intensities. The addition of coumarin to TI2Se-Pr2Se3 significantly affects the characteristic parameters of diodes. Kohlrausch function is used as an appropriate way to obtain the photo charge density (ρph) and the relaxation time constant from the photocurrent/capacitance transients. It is shown that coumarin doped chalcogenide films have a potential to obtain the photocarrier generation.

Pulsed UV laser-induced modifications in optical and structural characteristics of alpha-irradiated PM-355 SSNTD.

Pre- and postalpha-exposed PM-355 detectors were irradiated using UV laser with different number of pulses (100, 150, 200, 300, and 400). UV laser beam energy of 20mJ per pulse with a pulse width of 9ns was incident on an area of 19.6mm2 of the samples. XRD spectra indicated that for both reference and UV-irradiated samples, the structure is amorphous, but the crystallite size increases upon UV irradiation. The same results were obtained from SEM analysis. Optical properties of PM-355 polymeric solid-state nuclear track detectors were also investigated. Absorbance measurements for all PM-355 samples in the range of 200-400nm showed that the absorption edge had a blue shift up to a certain value, and then, it had an oscillating behavior. Photoluminescence spectra of PM-355 at 250nm revealed a decrease in the broadband peak intensity as a function of the number of UV pulses, while the wavelengths corresponding to the peaks had random shifts.

Photovoltaic and Impedance Spectroscopy Study of Screen-Printed TiO2 Based CdS Quantum Dot Sensitized Solar Cells.

Cadmium sulphide (CdS) quantum dot sensitized solar cells (QDSSCs) based on screen-printed TiO2 were assembled using a screen-printing technique. The CdS quantum dots (QDs) were grown by using the Successive Ionic Layer Adsorption and Reaction (SILAR) method. The optical properties were studied by UV-Vis absorbance spectroscopy. Photovoltaic characteristics and impedance spectroscopic measurements of CdS QDSSCs were carried out under air mass 1.5 illuminations. The experimental results of capacitance against voltage indicate a trend from positive to negative capacitance because of the injection of electrons from the Fluorine doped tin oxide (FTO) electrode into TiO2.