Near-infrared spectroscopy study of tourniquet-induced forearm ischaemia in patients with coronary artery disease

Near-Infrared Spectroscopy (NIR) can be employed to monitor local changes in haemodynamics and oxygenation of human tissues. A preliminary study has been performed in order to evaluate the NIRS transmittance response to induced forearm ischaemia in patients with coronary artery disease (CAD). The population consists in 40 patients with cardiovascular risk factors and angiographically documented CAD, compared to a group of 13 normal subjects. By inflating and subsequently deflating a cuff placed around the patient arm, an ischaemia has been induced and released, and the patients have been observed until recovery of the basal conditions. A custom LAIRS spectrometer (IRIS) has been used to collect the backscattered light intensities from the patient forearm throughout the ischaemic and the recovery phase. The time dependence of the near-infrared transmittance on the control group is consistent with the available literature. On the contrary, the magnitude and dynamics of the NIRS signal on the CAD patients show deviations from the documented normal behavior, which can be tentatively attributed to abnormal vessel stiffness. These preliminary results, while validating the performance of the IRIS spectrometer, are strongly conducive towards the applicability of the NIRS technique to ischaemia analysis and to endothelial dysfunction characterization in CAD patients with cardiovascular risk factors.Publisher PD

Near-infrared spectroscopy study of tourniquet-induced forearm ischaemia in patients with coronary artery disease

Near-Infrared Spectroscopy (NIRS) can be employed to monitor local changes in haemodynamics and oxygenation of human tissues. A preliminary study has been performed in order to evaluate the NIRS transmittance response to induced forearm ischaemia in patients with coronary artery disease (CAD). The population consists in 40 patients with cardiovascular risk factors and angiographically documented CAD, compared to a group of 13 normal subjects. By inflating and subsequently deflating a cuff placed around the patient arm, an ischaemia has been induced and released, and the patients have been observed until recovery of the basal conditions. A custom NIRS spectrometer (IRIS) has been used to collect the backscattered light intensities from the patient forearm throughout the ischaemic and the recovery phase. The time dependence of the near-infrared transmittance on the control group is consistent with the available literature. On the contrary, the magnitude and dynamics of the NIRS signal on the CAD patients show deviations from the documented normal behavior, which can be tentatively attributed to abnormal vessel stiffness. These preliminary results, while validating the performance of the IRIS spectrometer, are strongly conducive towards the applicability of the NIRS technique to ischaemia analysis and to endothelial dysfunction characterization in CAD patients with cardiovascular risk factors

Inspiratory muscle training and its effect on indices of physiological and perceived stress during incremental walking exercise in normobaric hypoxia

This study evaluated the effects of inspiratory muscle training (IMT) on inspiratory muscle fatigue (IMF) and physiological and perceptual responses during trekking-specific exercise. An 8-week IMT program was completed by 21 males (age 32.4 ± 9.61 years, VO2peak 58.8 ± 6.75 mL/kg/min) randomised within matched pairs to either the IMT group (n = 11) or the placebo group [(P), n = 9]. Twice daily, participants completed 30 (IMT) or 60 (P) inspiratory efforts using a Powerbreathe initially set at a resistance of 50% (IMT) or used at 15% (P) of maximal inspiratory pressure (MIP) throughout. A loaded (12.5 kg) 39-minute incremental walking protocol (3–5 km/hour and 1–15% gradient) was completed in normobaric hypoxia (PIO2 = 110 mmHg, 3000 m) before and after training. MIP increased from 164 to 188 cmH2O (18%) and from 161 to 171 cmH2O (6%) in the IMT and P groups (P = 0.02). The 95% CI for IMT showed a significant improvement in MIP (5.21±43.33 cmH2O), but not for P. IMF during exercise (MIP) was*5%, showing no training effect for either IMT or P (P = 0.23). Rating of perceived exertion (RPE) was consistently reduced (*1) throughout exercise following training for IMT, but not for P (P = 0.03). The mean blood lactate concentration during exercise was significantly reduced by 0.26 and 0.15 mmol/L in IMT and P (P = 0.00), with no differences between groups (P = 0.34). Rating of dyspnoea during exercise decreased (*0.4) following IMT but increased (*0.3) following P (P = 0.01). IMT may attenuate the increased physiological and perceived exercise stress experienced during normobaric hypoxia, which may benefit moderate altitude expedition

Driver roll speed influence in Ring Rolling process

Ring Rolling is an advanced local incremental forming technology to fabricate directly precise seamless ring-shape parts with various dimensions and materials. To produce a high-quality ring different speed laws should be defined: the speed laws of the Idle and Axial rolls must be set to control the ring cross section and the Driver roll angular velocity must be chosen to avoid too high localized deformation on the ring cross section. Usually, in industrial environment, a constant rotation is set for the Driver roll, but this approach does not guarantee a constant ring angular velocity because of its diameter expansion. In particular, the higher is the ring diameter the lower is its angular velocity. The main risk due to this constrain is the generation of a non-uniform ring geometry. An innovative approach is to design a Driver Roll speed law to obtain a constant ring angular velocity. In this paper a FEM approach was followed to investigate the Driver roll speed influence on the Ring Rolling process. Different Driver roll speed laws were tested starting from a model defined in an industrial plant. Results will be analyzed by a geometrical and physical point of view

Process parameters effect on mechanical properties and fatigue behaviour of friction stir weld AA6060 joints

Friction stir welding (FSW) is the most remarkable welding technology that has been invented and developed in the last decade. It is a solid-state welding process in which a rotating tool is driven into the material and translated along the interface of two or more plates. This technology has been successfully used to join materials that are considered difficult to be welded by fusion welding methods. FSW has potentially significant applications in many industrial fields such as aerospace, automotive, and naval industry. Anyway, FSW technology requires a meticulous understanding of the process and consequent mechanical properties of the welds in order to be used in the production of high performance components. The present work deals with an experimental campaign aimed at the evaluation of the mechanical properties of AA6060 T6 friction stir welded joints. The butt joints obtained using two different tool geometries (standard and threaded) were performed by varying the welding parameters, namely, tool rotating speed and feed rate. The standard tool was a very simple device fabricated using AISI 1040 steel, with a flat shoulder and a cylindrical pin. The threaded tool was a more complex device based on two main components: a tool holder, with a flat shoulder, and a threaded probe obtained using a commercial thread forming tap. The quality of the joints was evaluated in terms of both tensile strength (UTS) and fatigue behavior. The study of axial pulsing fatigue properties required the fabrication of a specific testing device able to avoid parasite bending moments. In order to estimate the more efficient and effective tool type, the welding forces (axial and longitudinal) were also measured

An approach to model interest for planetary rover through Dezert–Smarandache theory

In this paper, we propose an approach for assigning an interest level to the goals of a planetary rover. Assigning an interest level to goals allows the rover autonomously to transform and reallocate the goals. The interest level is defined by data-fusing payload and navigation information. The fusion yields an "interest map" that quantifies the level of interest of each area around the rover. In this way the planner can choose the most interesting scientific objectives to be analyzed, with limited human intervention, and reallocates its goals autonomously. The Dezert-Smarandache Theory of Plausible and Paradoxical Reasoning was used for information fusion: this theory allows dealing with vague and conflicting data. In particular, it allows us directly to model the behavior of the scientists that have to evaluate the relevance of a particular set of goals. The paper shows an application of the proposed approach to the generation of a reliable interest map

Locating the Nordstream explosions without a velocity model using polarization analysis

The seismic events that preceded the leaks in the Nordstream pipelines in the Baltic Sea have been interpreted as explosions on the seabed, most likely man-made. We use a polarization-based location method initially developed for marsquakes to locate the source region without a subsurface velocity model. We show that the 2 largest seismic events can be unambiguously attributed to the methane plumes observed on the sea surface. The two largest events can be located with this method, using 4 and 5 stations located around the source, with location uncertainties of 30km and 10x60km. We can further show that both events emitted seismic energy for at least ten minutes after the initial explosion, indicative of resonances in the water column or the depressurizing pipeline.Comment: 6 pages, 2 figures, submitted as fast report to Seismic

Photoexcitation in thin films deposited on silicon substrates by reactive pulsed laser ablation

Reactive pulsed laser ablation is a very interesting method to deposit thin films of several materials and compounds such as oxides, nitrides, semiconductors and superconductors. This technique relies on photoablation of pure elements, or a mixture of materials, with simultaneous exposure to a reactive atmosphere. In the case of oxides, reactions between the laser vaporized metals and oxygen lead to the formation of intermediate complexes and finally to oxide thin films. The reactivity of the plume has been already studied by our group in other oxides and nitrides productions and ascertained by Time of Flight Mass Spectrometry measurements [1].Thin films of semiconducting oxides such asIn2O3,SnO2, and multilayers of these two compounds have been deposited by Reactive Pulsed Laser Ablation, with the aim to evaluate the behaviour of such films under variable halogen lamp illumination.Deposition of these thin films has been carried out by a frequency doubled Nd-YAG laser (wavelength = 532 nm) on Silicon (100) substrates. A comparison, among indium oxide, tin oxide, and multilayers of indium and tin oxides, has been performed. The influence of physical parameters, such as substrate temperature and oxygen pressure in the deposition chamber, has been investigated. The deposited films have been characterized by Electric Resistance measurements