Estimation of Mechanical Properties of Soft Tissue Subjected to Dynamic Impact

This study attempted to estimate the damping properties of human tissue by using spring and damper system as a model. Data of impacting human tissue at the deltoid area was used to obtain a continuous, second order system to represent the mass-spring-damper system. A discrete ARMA(2,1) model was fitted using the data obtained from experiments in which the deceleration of a pendulum impacting human shoulders in the area of the deltoid muscle was measured. The data of the deceleration was integrated twice to obtain estimates of displacement. The integration was done until the maximum displacement occurred at zero velocity. An ARMA (2, 1) model was then fitted on the displacement data using the Data-Dependent-System (DDS) technique. The results were then converted to a continuous second order autoregressive model A(2) using the concept of Green’s Function and the auto covariance. Utilizing the principles of a mass-spring-damper system enabled the estimation of the spring constant (K) and damper constant (C) for each trail of the experiment. Estimates for both constants were found to be highly correlated with the mass of the impacting pendulum. Explanations for this string relationship were investigated

Characterisation of Saccharomyces cerevisiae hybrids selected for low volatile acidity formation and the production of aromatic Sauvignon blanc wine

Wine yeasts (Saccharomyces cerevisiae) vary in their ability to develop the full aroma potential of Sauvignon blanc wine due to an inability to release volatile thiols. Subsequently, the use of ‘thiolreleasing’ wine yeasts (TRWY) has increased in popularity. However, anecdotal evidence suggests that some commercially available TRWY intermittently exhibit undesirable characteristics for example, volatile acidity (VA) formation. Therefore, a trial was undertaken to select and evaluate S. cerevisiae hybrids for the production of Sauvignon blanc wine with enhanced fruity and tropical aromas, but low VA. Hybrids were characterised by clamped homogeneous electrical field (CHEF) DNA karyotyping and matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) biotyping, and subsequently trialled against top commercial TRWY that is, Zymaflore VL3 and Zymaflore X5 (Laffort Oenologie), and Fermicru 4F9 (DSM Oenology) in laboratory-scale Sauvignon blanc vinifications during 2013. Most hybrids produced wines with VA levels significantly lower than those produced with Zymaflore VL3, Zymaflore X5 and Fermicru 4F9. Low VA forming hybrids also produced wines with tropical wine aroma notes. Wines produced by Fermicru 4F9 had the lowest acetic acid (the main volatile acid) of the commercial TRWY in this study. However, some hybrid yeasts produced wines with less acetic acid on average than wines produced by Fermicru 4F9. Overall, hybrids NH 6, NH 48, NH 56, NH 88 and NH 145 produced wines with enhanced tropical fruity aroma, but lower VA compared to wines produced by commercial TRWY.Keywords: Hybrid yeasts, CHEF, MALDI-TOF/TOF MS biotyping, Sauvignon blanc, tropical fruit aroma, volatile acidit

Various characteristics of Ni and Pt–Al2O3 nanocatalysts prepared by microwave method to be applied in some petrochemical processes

AbstractAlumina-supported metal nanocatalysts were prepared via the microwave method, by loading nano Ni particles (at 1, 3 and 5wt%) or nano Pt particles (at 0.3, 0.6 and 0.9wt%). Structural and adsorption features of the nano catalysts were revealed through XRD, DSC-DTA, TEM, H2-chemisorption and N2-physisorption. N2-adsorption–desorption isotherms of type IV were related typically to mesoporous materials with H2 class of hysteresis loops characterizing ink bottle type of pores. The well dispersed nano-sized metal particles were evidenced in the studied catalytic systems, exhibiting marked thermal stability up to 800°C. The catalytic performances of different catalyst samples were assessed during cyclohexane, normal hexane and ethanol conversions, using the micro-catalytic pulse technique at different operating conditions. The 5% Ni–γ–Al2O3 sample was found to be the most active in dehydration of ethanol to produce ethylene, as well as in n-hexane cracking. However, the 1% Ni–Al2O3 sample showed the highest dehydrogenation activity for selective production of benzene from cyclohexane. On the other hand, the 0.9% Pt–γ–Al2O3 sample exhibited the highest activity in the dehydration of ethanol and in the dehydrogenation of cyclohexane. The 0.3% Pt–γ–Al2O3 sample was the most active in the dehydrocyclization of normal hexane, as compared to the other catalyst samples under study

Production of sensitive gas sensors using CuO/SnO2 nanoparticles

Metal oxide nanoparticles, such as CuO and SnO2, are outstanding systems for H2S gas sensing in air. In this work, those nanoparticles were deposited with different mixing percentages on substrates to form percolating networks of nanoparticles. Electrical electrodes were deposited on the nanoparticles’ films to investigate their gas sensing response against H2 and H2S, and their electrical characteristics. The sensor devices based on CuO–SnO2 nanoparticles revealed enhanced sensing characteristics against H2S with a sensitivity of 10 ppm. The enhanced sensing characteristics could be attributed to the formation of PN-junctions among CuO and SnO2 nanoparticles. The reasonable production cost (due to simple structure and cheap used materials), low power consumption ( ~ 1 µW for H2S at room temperature), high sensitivity, high response, and reasonable response time of the present sensors qualify them for practical implementation in portable gas sensing devices with enhanced characteristics.Open Access funding provided by the Qatar National Library. This work was supported by both Qatar National Research Fund (QNRF) under a Grant Number UREP21-035-2-013, and Qatar University fund under a Grant Number QUCG-CAS-20182019-1. The SEM/EDS measurements were accomplished in the Central Laboratories unit at Qatar University. Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations

Preventive effects of Salvia officinalis leaf extract on insulin resistance and inflammation in a model of high fat diet-induced obesity in mice that responds to rosiglitazone

Background Salvia officinalis (sage) is a native plant to the Mediterranean region and has been used for a long time in traditional medicine for various diseases. We investigated possible anti-diabetic, anti-inflammatory and anti-obesity effects of sage methanol (MetOH) extract in a nutritional mouse model of obesity, inflammation and insulin resistance, as well as its effects on lipolysis and lipogenesis in 3T3-L1 cells. Methods Diet-induced obese (DIO) mice were treated for 5 weeks with sage methanol extract (100 and 400 mg.kg-1/day. bid), or rosiglitazone (3 mg.kg-1/day. bid), as a positive control. Energy expenditure, food intake, body weight, fat mass, liver glycogen and lipid content were evaluated. Blood glucose, and plasma levels of insulin, lipids leptin and pro- and anti-inflammatory cytokines were measured throughout the experiment. The effects of sage MetOH extract on lipolysis and lipogenesis were tested in vitro in 3T3-L1 cells. Results After two weeks of treatment, the lower dose of sage MetOH extract decreased blood glucose and plasma insulin levels during an oral glucose tolerance test (OGTT). An insulin tolerance test (ITT), performed at day 29 confirmed that sage improved insulin sensitivity. Groups treated with low dose sage and rosiglitazone showed very similar effects on OGTT and ITT. Sage also improved HOMA-IR, triglycerides and NEFA. Treatment with the low dose increased the plasma levels of the anti-inflammatory cytokines IL-2, IL-4 and IL-10 and reduced the plasma level of the pro-inflammatory cytokines IL-12, TNF-α, and KC/GRO. The GC analysis revealed the presence of two PPARs agonist in sage MetOH extract. In vitro, the extract reduced in a dose-related manner the accumulation of lipid droplets; however no effect on lipolysis was observed. Conclusions Sage MetOH extract at low dose exhibits similar effects to rosiglitazone. It improves insulin sensitivity, inhibits lipogenesis in adipocytes and reduces inflammation as judged by plasma cytokines. Sage presents an alternative to pharmaceuticals for the treatment of diabetes and associated inflammation

Modelling and control of a multi-stage interleaved DC-DC converter with coupled inductors for super-capacitor energy storage system

Interleaved converters with coupled inductors are widely used to share load current in high power applications. It offers high equivalent switching frequency and reduced output current ripples using small size magnetic components. Due to smaller common-mode inductance, control system can be designed to achieve fast dynamic response. This paper proposes 8 channel interleaved DC/DC converter for interfacing super-capacitor energy storage system to a 400V DC voltage bus. Multi-stage interleaving magnetic circuit with two-phase coupling inductor as a building block is proposed. A methodology is developed to construct the model of the multi-stage magnetic circuit from the basic two-phase coupled inductor model. The derived model is successfully used to evaluate the system power losses and to design the magnetic circuit parameters and its current controller to fulfil the DC/DC converter steady state and dynamic performance specifications. A 20kW/four stage/8 channel DC/DC converter laboratory prototype has been built to connect a super-capacitor stack to 400V DC voltage bus. Experimental investigation validates the modeling, the system losses calculations and the design specifications of the system

Synthesis, physicochemical characterization, toxicity and efficacy of a PEG conjugate and a hybrid PEG conjugate nanoparticle formulation of the antibiotic moxifloxacin

Antibiotic resistance is increasing at such an alarming rate that it is now one of the greatest global health challenges. Undesirable toxic side-effects of the drugs lead to high rates of non-completion of treatment regimens which in turn leads to the development of drug resistance. We report on the development of delivery systems that enable antibiotics to be toxic against bacterial cells while sparing human cells. The broad-spectrum fluoroquinolone antibiotic moxifloxacin (Mox) was successfully conjugated to poly(ethylene glycol) (PEG) which was further encapsulated into the hydrophobic poly(3- caprolactone) (PCL) nanoparticles (NPs) with high efficiency, average particle size of 241.8 4 nm and negative zeta potential. Toxicity against erythrocytes and MDBK cell lines and drug release in human plasma were evaluated. Hemocompatibility and reduced cytotoxicity of the PEG–Mox and PCL(PEG– Mox) NPs were demonstrated in comparison to free Mox. Antimicrobial activity was assessed against drug sensitive and resistant: Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa and Klebsiella pneumoniae. The antibacterial activity of Mox was largely maintained after conjugation. Our data shows that the toxicity of Mox can be effectively attenuated while, in the case of PEG–Mox, retaining significant antibacterial activity. At the conditions employed in this study for antimicrobial activity the encapsulated conjugate (PCL(PEG–Mox) NPs) did not demonstrate, conclusively, significant antibacterial activity. These systems do, however, hold promise if further developed for improved treatment of bacterial infections.The National Research Foundation of South Africa and the Ministry of Higher Education and Scientific Research, Egypt.http://pubs.rsc.org/en/journals/journalissues/raam2021Chemistr

The Physical Processes of CME/ICME Evolution

As observed in Thomson-scattered white light, coronal mass ejections (CMEs) are manifest as large-scale expulsions of plasma magnetically driven from the corona in the most energetic eruptions from the Sun. It remains a tantalizing mystery as to how these erupting magnetic fields evolve to form the complex structures we observe in the solar wind at Earth. Here, we strive to provide a fresh perspective on the post-eruption and interplanetary evolution of CMEs, focusing on the physical processes that define the many complex interactions of the ejected plasma with its surroundings as it departs the corona and propagates through the heliosphere. We summarize the ways CMEs and their interplanetary CMEs (ICMEs) are rotated, reconfigured, deformed, deflected, decelerated and disguised during their journey through the solar wind. This study then leads to consideration of how structures originating in coronal eruptions can be connected to their far removed interplanetary counterparts. Given that ICMEs are the drivers of most geomagnetic storms (and the sole driver of extreme storms), this work provides a guide to the processes that must be considered in making space weather forecasts from remote observations of the corona.Peer reviewe