Differentiation of COVID-19 conditions in planar chest radiographs using optimized convolutional neural networks

In this study, an attempt has been made to differentiate Novel Coronavirus-2019 (COVID-19) conditions from healthy subjects in Chest radiographs using a simplified end-to-end Convolutional Neural Network (CNN) model and occlusion sensitivity maps. Early detection and faster automated screening of the COVID-19 patients is essential. For this, the images are considered from publicly available datasets. Significant biomarkers representing critical image features are extracted from CNN by experimentally investigating on cross-validation methods and hyperparameter settings. The performance of the network is evaluated using standard metrics. Perturbation based occlusion sensitivity maps are employed on the features obtained from the classification model to visualise the localization of abnormal areas. Results demonstrate that the simplified CNN model with optimised parameters is able to extract significant features with a sensitivity of 97.35% and F-measure of 96.71% to detect COVID-19 images. The algorithm achieves an Area Under the Curve-Receiver Operating Characteristic score of 99.4% with Matthews correlation coefficient of 0.93. High value of Diagnostic odds ratio is also obtained. Occlusion sensitivity maps provide precise localization of abnormal regions by identifying COVID-19 conditions. As early detection through chest radiographic images are useful for automated screening of the disease, this method appears to be clinically relevant in providing a visual diagnostic solution using a simplified and efficient model.

     

Isolation of Salmonella typhimurium from outbreak-associated cake mix

During May and June of 2005, 26 persons in several states were infected by a single strain (isolates indistinguishable by pulsed-field gel electrophoresis) of Salmonella enterica serotype Typhimurium after eating cake batter ice cream. The cake mix used to prepare the cake batter in the ice cream was implicated by epidemiologic investigation as the source of Salmonella contamination. Initial tests did not detect Salmonella in cake mix collected during the outbreak investigation. The objective of this study was to evaluate different procedures to isolate Salmonella from the implicated cake mix, cake, and ice cream. All outbreak-associated food samples (14 samples) were collected during the outbreak investigation by health departments of several of the states involved. Different combinations of Salmonella isolation procedures, including sample size, preenrichment broth, enrichment broth, enrichment temperature, and isolation medium, were used. Salmonella Typhimurium was isolated from two cake mix samples; the food isolates were indistinguishable from the outbreak pattern by pulsed-field gel electrophoresis subtyping. Universal preenrichment broth was substantially better than was lactose broth for preenrichment, and tetrathionate broth was better than was Rappaport-Vassiliadis broth for isolating Salmonella from the two positive cake mix samples. Although more typical Salmonella colonies were observed on plates from enrichment cultures grown at 35 degrees C, more confirmed Salmonella isolates were obtained from plates of enrichment cultures grown at 42 degrees C. Brilliant green agar, xylose lysine tergitol 4 agar, xylose lysine desoxycholate agar, Hektoen enteric agar, and bismuth sulfite agar plates were equally effective in isolating Salmonella from cake mix. The best combination of preenrichment-enrichment conditions for isolating the outbreak strain of Salmonella was preenrichment of cake mix samples in universal preenrichment broth at 35 degrees C for 24 h, followed by enrichment in tetrathionate broth at 42 degrees C for 24 h.     

Sensitization induced stress corrosion failure of AISI 347 stainless steel fractionator furnace tubes

Austenitic stainless steel tubes are used as furnace tubes in petrochemical industries mainly because of their corrosion resistance and mechanical strength. AISI 347 grade stainless steel is used as furnace heater tubes in the fractionator of hydrocracker unit. Even though this stainless steel is stabilized with the addition of niobium thus preventing sensitization related corrosion failures, operational and maintenance errors may result in premature failures if conditions prevail. The present work reports the premature failure of AISI 347 grade fractionator furnace tubes after nearly 8 years of service. The failure occurred after shutdown. Carbonaceous deposits were found on the inner walls of the tube and circumferential cracks were found beneath the deposit. The service exposed 347 SS alloy tube was in the sensitized condition as confirmed by microstructure and double loop electrochemical potentiodynamic reactivation test. The tube material got sensitized possibly by localized overheating at the carbon layer deposited site. During shutdown of hydrocracker unit polythionic acid formation occurred possibly due to errors in shutdown procedures. Sensitized alloy 347 tube undergone polythionic acid induced intergranular stress corrosion cracking (PASCC).     

Non-lithographic patterning of phage-displayed peptides with wrinkled elastomers

The development of controlled patterning of phage (viruses) could expand opportunities for both fundamental studies and creating various materials platforms. Inducing the elastomeric instability of PDMS film provides a non-lithographic, tuneable, controlled method for generating micro/nanoscale wrinkle patterns. Phage display has emerged as a powerful method for selecting peptides that possess enhanced selectivity and binding affinity toward a variety of targets. In this report, we demonstrate the non-lithographic patterning of phage-displayed peptides with wrinkled elastomers. Our results show that the phage-displayed peptides can be patterned on specific locations in controlled and tuneable ways, be transferred to other substrates and induce the self-assembly of hybrid materials. We anticipate that these results could open up exciting opportunities in fundamental studies and in applications ranging from sensors, hybrid materials, self-assembly, surface and interface, to micro/nanoelectronics.     

Cobalt–Polymer Nanocomposite Dielectrics for Miniaturized Antennas

Cobalt–polymer magnetic nanocomposites have been synthesized and characterized for their microstructure and properties such as permeability, permittivity, dielectric and magnetic losses from 100 MHz to 2 GHz to study their suitability as antenna dielectrics. Oxide-passivated cobalt nanoparticles were dispersed in epoxies to form nanocomposite toroids and thin-film resonator structures on organic substrates. Permeabilities of 2.10 and 2.65 were measured up to 500 MHz, respectively, with 25-nm to 50-nm and 5-nm nanoparticles in the nanocomposites. The loss tangent ranged from 0.02 to 0.04 at these frequencies. A combination of stable permeability of ～2 at 1 GHz to 2 GHz and permittivity of ～7 was achieved with nanocomposites having 5-nm nanoparticles. The magnetic nanomaterials described in this paper can overcome the limitations from domain-wall and eddy-current losses in microscale metal–polymer composites, leading to enhanced frequency stability. The paper also demonstrates integration of metal–polymer nanocomposites as thin-film build-up layers with two-metal-layer structures on organic substrates.     

Experimental determination of low order structure factors in the intermetallic compound TiAl

Rocking curves from several low order reflections in TiAl were recorded in digitized form using energy-filtered convergent beam electron diffraction in a transmission electron microscope. The low order reflections studied were 001, 002, 200, 111, 110, 220, 202, 113, and 311. These experimental rocking curves were simulated using computations based on the dynamic theory of electron diffraction. From these simulations, values of the X-ray structure factors for these reflections were deduced, and then used to determine charge difference maps for varioius plane sections in TiAl. These charge difference maps were compared with theoretical predictions, and it was found that there is a considerable degree of agreement between theory and experiment.     

Hypophosphataemia in patients undergoing bone marrow transplantation

We studied the prevalence of hypophosphataemia (< 0.80 mmol/l) in seventeen patients who had undergone bone marrow transplantation (BMT). Thirteen (77%) of the seventeen patients had hypophosphataemia at some stage during the conditioning phase or after their BMT. Seven (41%) of the seventeen patients had hypophosphataemia in the peri-BMT period that is during the conditioning phase or within one week thereafter. Two of the patients showed severe hypophosphataemia (< 0.30 mmol/l). We suggest that plasma phosphate should be monitored in patients with a bone marrow transplant.