Absorption correction of two-color laser-induced incandescence signals for soot volume fraction measurements

A numerical iterative procedure is presented for the evaluation of the effect of signal absorption in two-color laser-induced incandescence measurements. The correction process is applied to our experimental data in an axisymmetric flame [Appl. Opt. 44, 7414 (2005)]. The influence of signal trapping on peak soot temperature and on soot volume fraction has been found to be minimal. Some numerical tests were performed to investigate the effects of soot concentration, flame size, and soot refractive index on the magnitude of the signal absorption correction.     

Long-term operation and performance of cryogenic sapphire oscillators

Cryogenic sapphire oscillators (CSO) developed at the University of Western Australia (UWA) have now been in operation around the world continuously for many years. Such oscillators, due to their excellent spectral purity are essential for interrogating atomic frequency standards at the limit of quantum projection noise; otherwise aliasing effects will dominate the frequency stability due to the periodic sampling between successive interrogations of the atomic transition. Other applications, which have attracted attention in recent years, include tests on fundamental principles of physics, such as tests of Lorentz invariance. This paper reports on the long-term operation and performance of such oscillators. We compare the long-term drift of some different CSOs. The drift rates turn out to be linear over many years and in the same direction. However, the magnitude seems to vary by more than one order of magnitude between the oscillators, ranging from 10(14) per day to a few parts in 10(13) per day.     

On models of fractal networks

A couple of iterative models for the theoretical study of fractal networks whose topologies are generated via iterated function systems is presented: a lumped‐parameter impedor‐oriented one and a two‐port‐network‐oriented one. With the former, the voltage and current patterns give a detailed understanding of the electromagnetic fields' self‐similar distribution throughout the network; on the other hand, model complexity exponentially increases with the prefractal iteration order. The latter ‘black‐box’ model only controls port‐oriented global parameters that are the ones commonly used in the integration of different electronic systems, and its complexity is independent of prefractal order. Sierpinski gasket and carpet topologies are reported as examples. Copyright © 2008 John Wiley & Sons, Ltd.     

Fatty acids,health indices and sensory properties of Ricotta cheese from sheep fed three different diets

The study evaluates the healthy fatty acid profile and sensorial characteristics of Ricotta obtained from ewes fed three different diets: diet enriched with linseed (L), un‐supplemented diet (F) and pasture (P). Omega‐3 fatty acid (n‐3 FA) levels in Ricotta from grazing sheep and from animals that received the supplemented diet were notably higher than those that received un‐supplemented feed. The L‐ and P‐groups had lower levels of saturated fatty acids (SFAs), higher levels of conjugated linoleic acid (CLA) and more favourable health indices. Sensorial tests showed that among the diet groups, the Ricotta obtained from the supplementation group scored the highest with respect to greasiness, spreadability and acceptability.     

Increase in aflatoxins due to Aspergillus section Flavi multiplication during the aerobic deterioration of corn silage treated with different bacteria inocula

The growth of Aspergillus flavus and the production of aflatoxins (AF) during the aerobic deterioration of corn silage represent a problem for animal and human health. This experiment was conducted to evaluate whether the presence of A. flavus and AF production originate from the field or additional AF are produced during the fermentation phase or during aerobic deterioration of corn silage. The trial was carried out in northern Italy on corn at a dry matter (DM) level of 34%. The fresh herbage was either not treated (C) or treated with a Lactobacillus buchneri (LB) NCIMB 40788 [(at 3 × 10⁵ cfu/g of fresh matter (FM)], Lactobacillus hilgardii (LH) CNCM I-4785 (at 3 × 10⁵ cfu/g of FM), or their combination (LB+LH; at 1.5 × 10⁵ cfu/g of FM of each strain) ensiled in 20-L silos and opened after 250 d of ensiling. After silo opening, the aerobic stability was evaluated and samples were taken after 7 and 14 d of air exposure. The pre-ensiled material, the silages at silo opening, and the aerobically exposed silages were analyzed for DM content, fermentative profiles, microbial count, nutritive characteristics, DM losses, and AFB₁, AFB₂, AFG₁, and AFG₂ contents. Furthermore, a subsample of colonies with macromorphological features of Aspergillus section Flavi was selected for AF gene pattern characterization and in vitro AF production. The presence of A. flavus was below the detection limit (<1.00 log₁₀ cfu/g) in the fresh forage before ensiling, whereas it was found in 1 out of 16 silage samples at silo opening at a level of 1.24 log₁₀ cfu/g. The AF were found in both the fresh forage and at opening in all the samples, with a predominance of AFB₂ (mean value of 1.71 μg/kg of DM). The inoculation of lactic acid bacteria determined a reduction in the lactic-to-acetic ratio compared with the control. A larger amount of acetic acid resulted in a lower yeast count and higher aerobic stability in the treated silages than in the control ones. At the beginning of aerobic deterioration, the yeasts increased to over 5 log₁₀ cfu/g, whereas the molds were close to the value observed at silo opening. When the inhibiting conditions were depleted (pH and temperature higher than 5 and 35°C, respectively), both the total molds and A. flavus reached higher values than 8.00 and 4.00 log₁₀ cfu/g, respectively, thus determining the ex novo production of AFB₁ during aerobic deterioration, regardless of treatments. The analysis of gene pattern showed that 64% of the selected colonies of A. flavus showed the presence of all 4 AF gene patterns, and 43% of the selected colonies were able to produce AF in vitro. During air exposure, after 1,000°C·h have been cumulated, starch content decreased (below 10% DM) and concentration of neutral detergent fiber, acid detergent fiber, hemicelluloses, crude protein, and ash increased. The inoculation with LB and LB+LH increased the aerobic stability of the silages and delayed the onset of aerobic microbial degradation, which in turn indirectly reduced the risk of A. flavus outgrowth and AFB₁ production after silage opening.     

Biological Aspects of Selected Myokines in Skeletal Muscle: Focus on Aging

In the last decade, clear evidence has emerged that the cellular components of skeletal muscle are important sites for the release of proteins and peptides called “myokines”, suggesting that skeletal muscle plays the role of a secretory organ. After their secretion by muscles, these factors serve many biological functions, including the exertion of complex autocrine, paracrine and/or endocrine effects. In sum, myokines affect complex multi-organ processes, such as skeletal muscle trophism, metabolism, angiogenesis and immunological response to different physiological (physical activity, aging, etc.) or pathological states (cachexia, dysmetabolic conditions, chronic inflammation, etc.). The aim of this review is to describe in detail a number of myokines that are, to varying degrees, involved in skeletal muscle aging processes and belong to the group of proteins present in the functional environment surrounding the muscle cell known as the “Niche”. The particular myokines described are those that, acting both from within the cell and in an autocrine manner, have a defined relationship with the modulation of oxidative stress in muscle cells (mature or stem) involved in the regulatory (metabolic or regenerative) processes of muscle aging. Myostatin, IGF-1, NGF, S100 and irisin are examples of specific myokines that have peculiar features in their mechanisms of action. In particular, the potential role of one of the most recently characterized myokines—irisin, directly linked to an active lifestyle—in reducing if not reversing senescence-induced oxidative damage is discussed in terms of its possible application as an agent able to counteract the deleterious effects of muscle aging.     

Biometric,nutritional and sensory changes in intensively farmed Murray cod (Maccullochella peelii peelii, Mitchell) following different purging times

A period of purging before harvesting is common practice in intensive aquaculture to eliminate any possible off flavours from the fish. The present study was conducted to evaluate the biometrical, nutritional and sensory changes in intensively farmed Murray cod (Maccullochella peelii peelii) after 0, 2 and 4 weeks of purging. After the main biometric parameters were recorded, fish were analysed for proximate, fatty acid composition and flavour volatile compounds. A consumer preference test (triangle test) was also conducted to identify sensorial differences that may affect the consumer acceptability of the product.     

A 3D printed melt-compounded antibiotic loaded thermoplastic polyurethane heart valve ring design: an integrated framework of experimental material tests and numerical simulations

Abstract

Heart diseases are one of the commonest causes of death worldwide. These include valve pathologies such as valve stenosis, regurgitation, failure and similar, for which usually a valve substitution procedure is required. Different prosthesis alternatives (both biological and artificial) are nowadays available in the heart surgery panorama, but there are still issues and aspects to improve. The principal requirements for heart valve prostheses are an efficient fluid dynamic function and long-term durability without the need for anticoagulation therapy, coupled with the possibility of patient-specific customization. Given this scenario, the presented tasks might be fulfilled by the recent advances of additive manufacturing technology (AM), which offers versatility of shapes and materials to be printed.

In this work, the full flexibility of AM technique has been exploited to demonstrate the feasibility of a custom drug-loaded polymeric heart valve ring for crimpable prostheses. Two different medical-grade polymeric filaments for AM have been extruded: an aromatic Polyester-Based Thermoplastic Polyurethane (TPU-E) and a Thermoplastic Silicone-Polycarbonate-urethane compound filament (TSPCU). Both materials find different applications in medical fields, thanks to their mechanical and biocompatibility features.

A drug-loading procedure has been set to obtain an antibiotic-filled polymer material and the relative biocompatibility has been consequently investigated. Specimens have been printed with a Fused Deposition Method and uniaxial traction tests have been performed at different printing temperatures and infill orientation angles. To evaluate the damaging risk given by the HVR crimping process, a Finite Element (FE) simulation of the crimping load has been set.

The TSPCU has appeared to be the best material to realize the prosthesis in terms of tensile stress values. The ultimate mechanical characteristics of TSPCU have resulted to be higher if compared with TPU-E, regardless of raster orientation angle and temperature. The qualitative characterization of the drug loading process of TSPCU has been successful: standard disc diffusion method has revealed a well-defined inhibition zone on the bacterial culture. The effectiveness of the antibiotic has been maintained even after the extrusion and the printing process. The simulated crimping procedure on the HVR has revealed that the maximum Von Mises stress value is below the ultimate stress taken from experimental tests. The reported results demonstrate the feasibility of a crimpable antibiotic loaded HVR realized through TSPCU 3D printing.