Dry etch selectivity of Gd2O3 to GaN and AlN

Gd₂O₃ is a promising gate dielectric for GaN, but little is known of its dry etching characteristics. We achieved Gd₂O₃ etch rates up to ～600 Å · min^?1 in high density Cl2-based discharges, with maximum selectivities of ～15 over GaN and ～4 over AlN. Pure Cl₂ discharges produced reverse selectivities for both Gd₂O₃/GaN and Gd₂O₃/AlN, with typical values between 0.1–0.4. When a rare gas additive such as Ar or Xe was added to the plasma chemistry, the nitrides etched faster than the oxide. This indicates that volatile etch products (GaCl₃, AlCl₃, N₂) form in Cl₂-based plasmas once the GaN or AlN bonds are broken by ion bombardment, but that GdCl_x species are not volatile. In conjunction with the low efficiency for Gd₂O₃ bond-breaking at low ion energies, this leads to low selectivity.     

The role of cleaning conditions and epitaxial layer structure on reliability of Sc2O3 and MgO passivation on AlGaN/GaN HEMTS

The effect of layer structure (GaN versus AlGaN cap) and cleaning procedure prior to Sc₂O₃ or MgO deposition at 100 °C were examined for their effects on the long-term bias-stress stability of AlGaN/GaN high electron mobility transistors (HEMTs). Surface cleaning by itself was not sufficient to prevent current collapse in the devices. The forward and reverse gate leakage currents were decreased under most conditions upon deposition of the oxide passivation layers. After ≈13 h of bias-stressing, the MgO-passivated HEMTs retain 90% their initial drain–source current. The Sc₂O₃-passivated devices retained 80% recovery of the current under the same conditions.     

Antibacterial,Antibiofilm, and Antiviral Farnesol-Containing Nanoparticles Prevent Staphylococcus aureus from Drug Resistance Development

Multidrug antimicrobial resistance is a constantly growing health care issue associated with increased mortality and morbidity, and huge financial burden. Bacteria frequently form biofilm communities responsible for numerous persistent infections resistant to conventional antibiotics. Herein, novel nanoparticles (NPs) loaded with the natural bactericide farnesol (FSL NPs) are generated using high-intensity ultrasound. The nanoformulation of farnesol improved its antibacterial properties and demonstrated complete eradication of Staphylococcus aureus within less than 3 h, without inducing resistance development, and was able to 100% inhibit the establishment of a drug-resistant S. aureus biofilm. These antibiotic-free nano-antimicrobials also reduced the mature biofilm at a very low concentration of the active agent. In addition to the outstanding antibacterial properties, the engineered nano-entities demonstrated strong antiviral properties and inhibited the spike proteins of SARS-CoV-2 by up to 83%. The novel FSL NPs did not cause skin tissue irritation and did not induce the secretion of anti-inflammatory cytokines in a 3D skin tissue model. These results support the potential of these bio-based nano-actives to replace the existing antibiotics and they may be used for the development of topical pharmaceutic products for controlling microbial skin infections, without inducing resistance development.     

Novel technologies for monitoring the in‐line quality of virgin olive oil during manufacturing and storage

The quality of virgin olive oil is related to the agronomic conditions of the olive fruits and the process variables of the production process. Nowadays, food markets demand better products in terms of safety, health and organoleptic properties with competitive prices. Innovative techniques for process control, inspection and classification have been developed in order to to achieve these requirements. This paper presents a review of the most significant sensing technologies which are increasingly used in the olive oil industry to supervise and control the virgin olive oil production process. Throughout the present work, the main research studies in the literature that employ non‐invasive technologies such as infrared spectroscopy, computer vision, machine olfaction technology, electronic tongues and dielectric spectroscopy are analysed and their main results and conclusions are presented. These technologies are used on olive fruit, olive slurry and olive oil to determine parameters such as acidity, peroxide indexes, ripening indexes, organoleptic properties and minor components, among others. © 2016 Society of Chemical Industry     

A lumped parameter mathematical model to analyze the effects of tachycardia and bradycardia on the cardiovascular system

In this study, the cardiovascular system and heart hemodynamic performance are modeled using lumped method (electrical analogy) to evaluate the effects of abnormal heartbeats on the cardiovascular system performance. Lumped method (voltage–current relations of an electrical circuit) is able to simulate the cardiovascular (CV) system behavior in various physiological conditions. CV system consists of 42 compartments, including artery, vein, capillary set, and heart chambers. Each blood circulatory subsystem (compartment) is modeled using electrical elements, such as resistor, capacitor, and inductor. In this study, by utilizing lumped model, CV system is simulated in matlab software (SIMULINK environment). There are two major types of irregular heart rates. In tachycardia, the heartbeats are too quick: over 100 beats per minute. In bradycardia, the heart beat is too slow: less than 60 beats per minute. Healthy blood circulation and heart performance are modeled (heartbeat: 75 beat/minute), and the results such as left atrium outflow‐time graph and pressure‐time diagram of aorta artery and pulmonary circulation are obtained. The present results are found to be in agreement with numerical and experimental studies. Then, by increasing and decreasing the heartbeat, the abnormality (150 and 50 beat/minute representing tachycardia and bradycardia, respectively) is simulated. The results show that the tachycardia leads to a significant reduction of capillary blood flow into less than 100 ml/s, while it exceeds 100 ml/s when heart has normal function. The results of the present study have clinical implications for detailed diagnosis of CV diseases when experimental studies have limitation. Copyright © 2014 John Wiley & Sons, Ltd.