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Strengthening mechanisms, which are commonly exploited by conventional alloys, can be effectively incorporated in high entropy alloys (HEAs) to improve their mechanical behaviour. In this light, compositional modification of equiatomic HEAs can be pursued in order to obtain specific microstructural features. Herein, a face centred cubic CoCuFeMnNi alloy was modified by the addition of a proper amount of Ti; a dedicated thermal treatment allowed to concurrently activate two different phase formation mechanisms, i.e. precipitation and spinodal decomposition. This resulted in a nanostructured microstructure, characterized by the presence of periodic modulations of Cu content and by nanosized coherent L12 Ni3Ti precipitates. Such microstructure resulted in a more than 100 % increase of yield strength after ageing treatment and allowed to retain a satisfactory ductility. Advanced microstructural characterization, coupled with the application of semi-empirical models allowed to understand the role of each microstructural feature in determining the alloy’s mechanical strength.

One of the chief features of this global crisis is that we find ourselves in a shifting landscape. The resulting disorientation extends beyond health research and into many domains of our individual and collective lives. We suffer from political disorientation (the need for a radical shift in economic thinking), from social disorientation (the rearrangement of social dynamics based on distancing measures), and from temporal disorientation (the warping of our sense of time during lockdown), to name but a few. This generalised state of disorientation has substantial effects on wellbeing and decision making. In this paper, we review the multiple dimensions of disorientation of the COVID-19 crisis and use state-of-the art research on disorientation to gain insight into the social, psychological and political dynamics of the current pandemic. Just like standard, spatial cases of disorientation, the non-spatial forms of disorientation prevalent in the current crisis consist in the mismatch between our frames of reference and our immediate experience, and they result in anxiety, helplessness and isolation, but also in the possibility of re-orienting. The current crisis provides a unique environment in which to study non-spatial forms of disorientation. In turn, existing knowledge about spatial disorientation can shed light on the shifting landscape of the COVID-19 pandemic. © Bristol University Press 2021.

AZ91 magnesium alloy parts were successfully produced using a novel extrusion-based additive manufacturing process. The green parts were built in two different orientations and subjected to debindi...

The present paper is the result of the collaboration between the Engineering Department of Messina University and the car company Maserati S.p.A. The aim of this paper is to determine the T-N torsion fatigue curve at R= -1 of the mechanical system "front halfshaft" of an existing car. In particular, experimental fatigue tests were carried out in the laboratories of the Engineering Department of the University of Messina. Torsion fatigue tests of the entire mechanical system were carried out on 15 different front halfshafts. Evaluations of the crack propagation and of failure analysis were made to determine the causes of breakage. In conclusion, the T-N fatigue curve of the mechanical system "front halfshaft" has been obtained.

Recently, Fe and Fe-based alloys have shown their potential as degradable materials for biomedical applications. Nevertheless, the slow corrosion rate limits their performance in certain situations. The shift to iron matrix composites represents a possible approach, not only to improve the mechanical properties, but also to accelerate and tune the corrosion rate in a physiological environment. In this work, Fe-based composites reinforced by Mg

A multicentre survey of the quality control of 99 Tc m generators has been completed : 245 generators from seven different commercial sources were tested over a period of 2 years. The results indicate that the mean pH of the eluates was 5.8 ± 0.6; the aluminium contents were typically < 10 ppm; the radiochemical purity was 99.8 ± 0.4% and the median 99 Mo content was 3.8 × 10 -4 percent. The elution profiles gave a volume of 1.9 ml to obtain 50% of the total eluted activity and of 4.9 ml to obtain 95%. Other radionuclide impurities and heavy metal breakthrough were evaluated by graphite furnace absorption spectrometry and inductively coupled plasma mass spectrometry. National guidelines for the standardization of radiopharmacy procedures are currently being compiled.

There have been a number of indications that sex hormones can affect the rate of growth of meningiomas during pregnancy. The presence of oestrogen or progesterone receptors in meningiomas and the influence of sex hormones upon cell cultures derived from human meningiomas have been extensively investigated. The results have been controversial, with most of the discussion centring upon the presence and possible role of oestrogen receptors. The aim of the present study was to assess oestrogen receptors in human meningiomas with 16α[ 18 F]fluoro-17β-oestradiol ([ 18 F]FES) and positron emission tomography (PET). With this purpose in mind, we measured the regional brain uptake of [ 18 F]FES in six patients with a neuroradiological and histological diagnosis of meningioma, comparing the in vivo PET data with the immunohistological analysis of oestrogen receptors performed on formalin-fixed, paraffin-embedded tissue obtained at surgery. Two analyses were used for the in vivo measurement of [ 18 F]FES binding to oestrogen receptors: the ratio of tumour activity to that of normal tissue (T/NT), calculated 90 min after tracer injection, and the ratio between the equilibrium distribution volume (DV) in normal and pathological tissues, calculated by means of a graphical kinetic analysis. PET studies demonstrated a marked uptake of [ 18 F]FES by the tumour in four of the six patients. Immunohistochemical assay using a manual staining method capable of detecting oestrogen receptors at a level of > 10 pmol mg -1 of protein detected only sparse immunostaining in one of the six meningiomas. Distinct albeit weak immunostaining was demonstrated in five of the six meningiomas when the sensitivity of the immunohistochemical assay was increased to < 10 pmol mg -1 of protein by use of an automated staining method (Bioteck 1000). Comparison of the in vivo and immunohistochemical results showed a correlation in five of the six patients, thus indicating the high sensitivity of [ 18 F]FES for the in vivo evaluation of oestrogen receptor expression.

A cellular automaton-based model is presented to investigate the influence of an electromagnetic field on microtubule formation dynamics. The cellular space is assumed to represent a portion of the cytoplasm through which the electromagnetic field propagates. Tubulin dimers are seen as dipoles having two states of polarization, and the field is seen as a stream of photons. Both kinds of particles move all over the cellular space. Their interactions are represented as local elementary processes of photon absorption and emission. The effects of the ponderomotive force exerted by the field on the dimers and diffusion are taken into account. Simulation experiments show that a monochromatic electromagnetic beam with a bell-shaped transverse profile can give rise to filamentary regions where the dimer concentration is increased, thus creating a precondition for polymerization.

Estrogen receptors are expressed in several brain areas of various animal species, and steroid hormones exert physiologic and biochemical effects on the central nervous system. The aim of the present study was to evaluate in female adult rats, the suitability of 16α[18F]fluoro-17β-estradiol ([18F]FES), a selective estrogen receptor ligand, for the in vivo assessment of brain estrogen receptors. This was considered to be a preliminary step in evaluating the potential usefulness of [18F]FES for studies of cerebral estrogen receptors with positron emission tomography (PET) in nonhuman primates and human subjects. We evaluated (a) the time course of the metabolic degradation of [18F]FES in blood; (b) the time course of distribution of the tracer in discrete cerebral areas; (c) the inhibitory effect of increasing doses of cold estradiol on cerebral [18F]FES uptake; and (d) the possibility of in vivo quantification of estrogen receptor binding parameters using both equilibrium and dynamic kinetic analyses. We quantified [18F]FES binding to estrogen receptors using both equilibrium and dynamic kinetic analyses. The results of this study indicate that [18F]FES is a suitable tracer for the measurement of estrogen receptors in the pituitary and hypothalamus, using either the equilibrium or the kinetic analysis. However, [18F]FES is inadequate for the in vivo investigation of estrogen binding sites in brain areas with low receptor density, such as the hippocampus.

We addressed the problem of the circadian changes in neural control of heart period in ambulant hypertensive subjects. A running spectral analysis of R-R variability from Holter tapes provided markers of sympathetic, i.e. low-frequency component (LF) almost equal to 0.10 Hz, and vagal, i.e. high-frequency component (HF) almost equal to 0.25 Hz, controlling activities for the 24-h period of the recording. Significant circadian differences were observed in LF between the two groups of subjects: during night-time rest (0300-0400 h), LF was greater in hypertensives than in normotensives (56 +/- 2 and 48 +/- 2 nu, respectively; P less than 0.05). Furthermore, the difference between daytime and night-time LF values was progressively reduced with increasing severity of the hypertensive state, as assessed by resting arterial pressure levels. Spectral analysis of R-R variability suggests that essential hypertension may be characterized by a reduced day-night oscillation in sympathetic activity than can be quantified non-invasively using this approach.

A Cellular Automata (CA) approach is proposed for a microscopic description of elementary matter-radiation interaction processes, which provides an equal opportunity treatment both of matter and radiation state. In particular the case of a semiconductor laser device is investigated. The description of this simple laser structure is preliminary to extending the CA approach to more complex matter-radiation interactions as those deriving from electrostriction and Kerr effects.

Emission Tomography (ET) investigates physiological parameters and biochemical reactions in vivo in humans. Positron Emission Tomography (PET) is based on x-ray computerized tomography (CT) principles and provides a tomographic representation of tissue radioactivity due to positrons, such as carbon (C-11), oxygen (0-15), nitrogen (N-13), and fluorine (F-18).

A rapid and precise method for the measurement of the mass of 16α[ 18 F]fluoro-estra-1,3,5(10)-triene-3,17β-diol by GC—MS is reported. The advantages of this technique over others more widely used are discussed.

In anesthetized and artificially ventilated cats, we recorded the impulse activity of 23 afferent sympathetic unmyelinated fibers with left ventricular endings, dissected from the left sympathetic rami T3 and T4. All fibers displayed a spontaneous discharge at a rate of 0.79 +/- 0.2 (mean +/- SE) impulses/sec. During constriction of the thoracic aorta, the discharge increased to 1.92 +/- 0.2 impulses/sec. During myocardial ischemia, produced by interruption of left main coronary artery perfusion, supplied through an extracorporeal pump, the impulse activity increased to 1.73 +/- 0.3 impulses/sec. The mean latency for this excitation was 16.5 +/- 1.5 sec. The intracoronary administration of bradykinin (5 and 10 ng/kg) elicited a marked increase in impulse activity that, following 5 ng/kg, reached 2.06 +/- 0.2 impulses/sec, after a latency of 18 +/- 2 sec and in absence of significant hemodynamic changes. Myocardial ischemia and bradykinin never revealed the existence of silent afferent fibers included in the split nerve strand. The results obtained with this experimental model indicate that the ventricular endings of these afferent sympathetic unmyelinated fibers act as "polymodal" receptors. We hypothesize that the peripheral mechanism for cardiac nociception involves intensive excitation of fibers discharging spontaneously and not recruitment of silent fibers which are purely nociceptive in function.

1. We recorded the electrical impulse activity of thirty-three single afferent fibres with left ventricular endings from the third and fourth left thoracic sympathetic rami communicantes of anaesthetized cats. Their conduction velocity ranged from 0.23 to 0.98 m/sec (group C). 2. The endings of each fibre were localized to the left ventricle by mechanical probing performed at the end of the experiment on the non-beating heart. No fibre had multiple sensory fields. 3. The impulse activity (0.95 +/- 0.2 impulses/sec) was spontaneous but most often a fixed temporal correlation between impulses and ventricular dynamics was not detectable. It was increased during occlusion of the thoracic aorta, I.V. administration of isoprenaline or infusion of saline. It was unaffected by asphyxia, haemorrhage and I.V. administration of acetylcholine. It was decreased during occlusion of inferior vena cava. Therefore these ventricular receptors appeared to be mainly sensitive to mechanical events. 4. The fibres were excited during the occlusion of the left main coronary artery, after a latency of 14.5 +/- 1.3 sec. They were also excited during ventricular fibrillation, exhibiting the highest values of impulse activity (2.51 +/- 0.4 impulses/sec). The increase in impulse activity during ventricular fibrillation was sometimes immediate and extreme, with peak frequencies of about 50 impulses/sec. 5. These spontaneously active ventricular receptors with unmyelinated nerve fibres participate in the transmission of the continuous impulse activity which from the cardiovascular system reaches the spinal cord through the sympathetic nerves and which is likely to contribute to the neural control of circulation. Thus the unmyelinated cardiac sympathetic afferents should not be considered as purely nociceptive in function.

The influence of beta-adrenergic receptor blockade on the impulse activity of 21 cardiovascular sympathetic afferent nerve fibers (11 from the thoracic aorta, 10 from the pulmonary veins), isolated from the left sympathetic rami communicantes T-3 and T-4 was studied in anesthetized, vagotomized cats. Aortic pressure, heart rate, and neural discharge were recorded during control conditions and during brief aortic occlusions of comparable amplitude and duration. Administration of dl-propranolol (0.2-0-4 mg/kg) did not modify aortic pressure or neural discharge of the fibers during control conditions, although, as expected, heart rate was diminished. dl-Propranolol administration did change the response of cardiovascular sympathetic afferents to similar aortic pressure increases. Before drug administration, aortic occlusion caused a significant increase in neural discharge of both aortic and pulmonary vein sympathetic afferent fibers, from 0.52 +/- 0.12 to 1.64 +/- 0.31 and from 0.67 +/- 0.10 to 2.08 +/- 0.25 impulses/sec, respectively (p less than 0.05). After dl-propranolol administration, comparable increases in aortic pressure resulted in slight but not significant increases in neural discharge of aortic and pulmonary vein fibers. Administration of d-propranolol (0.4-0.6 mg/kg), which possesses only membrane-stabilizing properties, did not modify the firing rate of four pulmonary sympathetic afferents, which subsequently decreased their response to pressure rises after administration of dl-propranolol. These results indicate that beta-adrenergic receptor blockade reduces the responsiveness to hemodynamic stimuli of sympathetic cardiovascular afferent fibers that are capable of mediating excitatory pressor reflexes.

Ethyl 4,4-dimethoxy-3-methylbut-2-enoate, (1; R = CO2Et) has been prepared as a mixture of (E) and (Z)-isomers, the (E)/(Z) ratio depending on the base used. Each isomeric mixture of (1a) and (1b) has been used as substrate for biohydrogenation with fermenting Saccharomyces cerevisiae(baker's yeast) and the (Z)-isomer seems to be the preferred substrate. (E)-Unsaturated alcohols such as (3a) and (5d) are not reduced to the corresponding saturated hydroxy derivatives by baker's yeast. The (E)-aldehyde (3c) and its acetal (3d) are mainly reduced to the corresponding (E)-alcohol (3a),;the saturated hydroxy ester (2a) being formed to a minor extent, especially with (3d). In contrast, biohydrogenation is also successful with the (E)-isomers of compounds (3e), (3f), and (3b)(R2= alkyl or alkenyl). If the allylic oxygenated group to be reduced is not α-methyl substituted, reduction to the corresponding saturated alcohols readily occurs with the (E)-isomers as in the case of (5f). For this last biohydrogenation, the stereochemistry of the methyl-bearing, carbon has been established. by chemical correlations. The α,β-disubstituted allylic acetal (6a) is not biohydrogenated by the yeast, but a mixture of unsaturated hydroxy ester (6b) and γ-hydroxy lactone (8) is recovered from the incubation.

We studied heart rate variability in 49 uncomplicated diabetics (27 with insulin therapy; 22 with oral hypoglycemic agents) and in 40 age-matched controls. An automatic autoregressive algorithm was used to compute the power spectral density (PSD) of beat by beat RR variability derived from the surface ECG. The PSD contains two major components (a low frequency approximately 0.1 Hz (LF) and a high frequency, respiratory linked, approximately 0.25 Hz (HF] that provide, respectively, quantitative markers of sympathetic and vagal modulatory activities and of their balance. As compared to controls, in diabetics, besides a reduced RR variance at rest (2722 +/- 300 and 1436 +/- 241 ms2, respectively), we observed during passive tilt an altered response of spectral indices of sympathetic activation and vagal withdrawal, suggestive of a complex modification in the neural control activities. In addition, we compared this approach to the commonly used clinical tests score, and observed that the latter provides overall results similar to those obtained with spectral changes induced by tilt (r = 0.42; P less than 0.01). Of potential clinical importance is that the data obtained with spectral analysis appear more thoroughly quantifiable and do not require the active collaboration of the patients.

Ethyl 4,4-dimethoxy-3-methylbut-2-enoate, (1; R = CO2Et) has been prepared as a mixture of (E) and (Z)-isomers, the (E)/(Z) ratio depending on the base used. Each isomeric mixture of (1a) and (1b) has been used as substrate for biohydrogenation with fermenting Saccharomyces cerevisiae(baker's yeast) and the (Z)-isomer seems to be the preferred substrate. (E)-Unsaturated alcohols such as (3a) and (5d) are not reduced to the corresponding saturated hydroxy derivatives by baker's yeast. The (E)-aldehyde (3c) and its acetal (3d) are mainly reduced to the corresponding (E)-alcohol (3a),;the saturated hydroxy ester (2a) being formed to a minor extent, especially with (3d). In contrast, biohydrogenation is also successful with the (E)-isomers of compounds (3e), (3f), and (3b)(R2= alkyl or alkenyl). If the allylic oxygenated group to be reduced is not α-methyl substituted, reduction to the corresponding saturated alcohols readily occurs with the (E)-isomers as in the case of (5f). For this last biohydrogenation, the stereochemistry of the methyl-bearing, carbon has been established. by chemical correlations. The α,β-disubstituted allylic acetal (6a) is not biohydrogenated by the yeast, but a mixture of unsaturated hydroxy ester (6b) and γ-hydroxy lactone (8) is recovered from the incubation.