The Antimicrobial Peptide Temporin G: Anti-Biofilm,Anti-Persister Activities,and Potentiator Effect of Tobramycin Efficacy Against Staphylococcus aureus

Bacterial biofilms are a serious threat for human health, and the Gram-positive bacterium Staphylococcus aureus is one of the microorganisms that can easily switch from a planktonic to a sessile lifestyle, providing protection from a large variety of adverse environmental conditions. Dormant non-dividing cells with low metabolic activity, named persisters, are tolerant to antibiotic treatment and are the principal cause of recalcitrant and resistant infections, including skin infections. Antimicrobial peptides (AMPs) hold promise as new anti-infective agents to treat such infections. Here for the first time, we investigated the activity of the frog-skin AMP temporin G (TG) against preformed S. aureus biofilm including persisters, as well as its efficacy in combination with tobramycin, in inhibiting S. aureus growth. TG was found to provoke ~50 to 100% reduction of biofilm viability in the concentration range from 12.5 to 100 µM vs ATCC and clinical isolates and to be active against persister cells (about 70–80% killing at 50–100 µM). Notably, sub-inhibitory concentrations of TG in combination with tobramycin were able to significantly reduce S. aureus growth, potentiating the antibiotic power. No critical cytotoxicity was detected when TG was tested in vitro up to 100 µM against human keratinocytes, confirming its safety profile for the development of a new potential anti-infective drug, especially for treatment of bacterial skin infections.     

Multi-objective design optimization of a new space radiator

In this work different multi-objective techniques are used to the conceptual design of a new kind of space radiator. Called VESPAR (Variable Emittance Space Radiator), the radiator has an effective variable emittance which makes it able to reduce or avoid the demand for heater power to warm up equipment during cold case operations in orbit. The multi-objective approach was aimed on obtaining a radiator that minimize its mass while at the same time minimize the need for heater power during cold case. Four multi-objective algorithms were used: Elitist Non-dominated Sorting Genetic Algorithm (NSGA-II), Multi-Objective Genetic Algorithm (MOGA), Multi-Objective Simulating Annealing (MOSA) and Multi-Objective Generalized Extremal Optimization (M-GEO). The first three algorithms were used under the modeFrontier^® optimization software package, while M-GEO is a recently proposed multi-objective implementation of the Generalized Extremal Optimization (GEO) algorithm. The Pareto frontier showing the trade-off solutions between radiator mass and heater power consumption is obtained by the four algorithms and the results compared. An assessment of the performance of M-GEO on this problem, compared to the other well-known multi-objective algorithms is also made.     

Biodiesel production from waste coconut oil by esterification with ethanol: The effect of water removal by adsorption

The production of biodiesel by esterification with ethanol using waste oil generated in the refining of coconut oil was investigated in this study. The reaction was performed with and without adsorption of water in order to verify the effect of removing water on the reaction conversion. Methanol was also evaluated as an esterification agent. For both ethanol and methanol, conversions over 99% mol were observed. Simultaneous water adsorption allowed the use of lower alcohol/oil molar ratios thus enabling better economics to a possible industrial process.     

A framework for risk assessment and decision-making strategies in dangerous good transportation

The risk from dangerous goods transport by road and strategies for selecting road load/routes are faced in this paper, by developing an original site-oriented framework of general applicability at local level. A realistic evaluation of the frequency must take into account on one side inherent factors (e.g. tunnels, rail bridges, bend radii, slope, characteristics of neighborhood, etc.) on the other side factors correlated to the traffic conditions (e.g. dangerous goods trucks, etc.). Field data were collected on the selected highway, by systematic investigation, providing input data for a database reporting tendencies and intrinsic parameter/site-oriented statistics. The developed technique was applied to a pilot area, considering both the individual risk and societal risk and making reference to flammable and explosive scenarios. In this way, a risk assessment, sensitive to route features and population exposed, is proposed, so that the overall uncertainties in risk analysis can be lowered.     

Development and optimization of a mid-infrared hollow waveguide gas sensor combined with a supported capillary membrane sampler

A gas sensor for application in water analysis was developed by combination of a mid-infrared (MIR) hollow waveguide with a Fourier transform infrared (FT-IR) spectrometer and coupling of the hollow waveguide gas sensor module to a supported capillary membrane sampler (SCMS) for continuous liquid-gas extraction. Different hollow waveguides have been characterized in this study for developing an optimized optical configuration. Analysis of industrially relevant compounds has been performed, investigating chlorinated hydrocarbons (CHCs), such as dichloromethane and chloroform, representing highly volatile analytes, and 1,4-dioxane as an example of target compounds with low volatility. The suitability of this spectroscopic IR sensing system for industrial applications is demonstrated under simulated real-world conditions with limits of detection in the ppb (v/v) and ppm (v/v) concentration range for CHCs and 1,4-dioxane, respectively.     

A network flow based heuristic approach for optimising AGV movements

Automated Guided Vehicles (AGVs) are driverless carriers that automatically navigate along planned paths by means of several guidance and control methods. This paper proposes an approach for solving the dispatching problem in an AGV system. The problem is modelled through a network by relying on the formulation of a Minimum Cost Flow Problem. In the defined graph, the nodes represent transportation tasks and AGVs while the arcs consider, through the associated weights, several system’s aspects such as pick, drop, and travel times, battery recharging, capacity constraints, congestion and error issues. Two objectives can be achieved: (i) minimisation of the average time for carrying out transportation tasks or (ii) maximisation of the utilisation degree of AGVs. The modelling and solution approach adopted has provided a novel Vehicle–Initiated dispatching rule and parameters settings for the dynamic assignments of transportation missions to AGVs. The decision making process concurrently and dynamically considers several factors. The results show a relevant reduction in the average time for transportation order fulfilment and a decrease in its variability. The proposed approach has been exploited for optimising the AGVs performance in a pharmaceutical production system.     

Power limits for secondary devices operating on TV white spaces

The use of TV white spaces as an alternative to overcome spectrum scarcity is a huge opportunity for new telecommunication systems and services. While being attractive for its desirable propagation characteristics, this part of the spectrum imposes a major difficulty from design and regulatory perspectives: how to optimize the use of spectrum and to ensure the protection of primary users, TV systems for example, at the same time. This paper discusses strategies to be adopted by geo-location database operators to calculate adaptive maximum permitted power levels for secondary devices, according to permissible levels of interference into the digital terrestrial television primary system.     

Oleic acid esterification with ethanol under continuous water removal conditions

The production of ethyl ester was investigated using a new reaction system consisting of a reactor coupled to an adsorption column. The adsorption system was used to shift the equilibrium toward ethyl ester production by removing the water from commercial ethanol and the water produced during the esterification reaction. A condenser placed above the adsorption column was responsible to condensate the vapor, returning water free ethanol to the reactor. Ethyl ester was produced by esterification of oleic acid and ethanol using sulfuric acid as catalyst. The results showed a yield of 99.9%. The best operating condition was found operating the reactor at 110 °C, 1% of catalyst (w/w) and with an oleic acid to ethanol ratio of 1:3.