1,523 research outputs found
About the use of entanglement in the optical implementation of quantum information processing
We review some applications of entanglement to improve quantum measurements
and communication, with the main focus on the optical implementation of quantum
information processing. The evolution of continuos variable entangled states in
active optical fibers is also analyzed.Comment: 8pages, invited contribution to Quant. Interf. IV (ICTP Trieste 2002
Matrix Metalloproteases in Arterial Hypertension and their Trend after Antihypertensive Treatment
Background/Aims: Arterial hypertension is characterized by vascular remodelling, atherosclerosis and cardiovascular complications. Matrix metalloproteases (MPPs) are endopeptidases produced by all the cells present in the vascular wall and are involved in the regulation of the extracellular matrix protein turnover. MMPs contribute to blood vessel formation, remodelling, angiogenesis; whereas an altered expression or activity of MMPs or their tissue inhibitors (TIMPs) results correlated with the development and progression of cardiovascular complications. Methods: We examined the literature data regarding the role of MMPs in human hypertension, including their involvement in vascular remodelling, and the effects of some antihypertensive molecules on these MMP/TIMP profile. Results: The expression and the activity of some MMPs and TIMPs are impaired in human hypertension. An altered MMPs/TIMPs balance plays an important role in the vascular wall rearrangement, in response to hemodynamic changes which may induce myocardial hypertrophy and fibrosis leading to ventricular remodelling. Several studies have examined the effects of some antihypertensive molecules, such as ACE inhibitors, angiotensin receptor blockers, calcium-channel blockers, and aldosterone antagonists, on the MMPs/TIMPs profile by obtaining positive results. Conclusion: Considering the data taken into consideration, the authors believe that in clinical practice a strategic antihypertensive therapy directed to the MMPs profile, may be useful to decrease the risk of cardiovascular complications
Optimisation of bitumen emulsion properties for ballast stabilisation
: Ballasted track, while providing economical and practical advantages, is associated with high costs
and material consumption due to frequent maintenance. More sustainable alternatives to conventional ballasted
trackbeds should therefore aim at extending its durability, particularly considering ongoing increases in traffic
speed and loads. In this regard, the authors have investigated a solution consisting of bitumen stabilised ballast (BSB), designed to be used for new trackbeds as well as in reinforcing existing ones. This study presents the
idea behind the technology and then focuses on a specific part of its development: the optimisation of bitumen
emulsion properties and dosage in relation to ballast field conditions. Results showed that overall bitumen stabilisation improved ballast resistance to permanent deformation by enhancing stiffness and damping properties.
Scenarios with higher dosage of bitumen emulsion, higher viscosity, quicker setting behaviour, and harder base
bitumen seem to represent the most desirable conditions to achieve enhanced in-field performanc
Hemorheological abnormalities in human arterial hypertension
Blood rheology is impaired in hypertensive patients. The alteration involves blood and plasma viscosity, and the erythrocyte behaviour is often abnormal. The hemorheological pattern appears to be related to some pathophysiological mechanisms of hypertension and to organ damage, in particular left ventricular hypertrophy and myocardial ischemia. Abnormalities have been observed in erythrocyte membrane fluidity, explored by fluorescence spectroscopy and electron spin resonance. This may be relevant for red cell flow in microvessels and oxygen delivery to tissues. Although blood viscosity is not a direct target of antihypertensive therapy, the rheological properties of blood play a role in the pathophysiology of arterial hypertension and its vascular complications
An “Unexpected” Rock Failure in a Limestone Open Pit Mine
On 28th October 2004 a rock failure occurred in a limestone open pit quarry in Tuscany (Italy). The phenomenon evolved slowly with the collapse of about 1000 cubic meters. The complex failure mechanism mainly involved plane sliding along stratifications with rotation and block toppling. The phenomenon continued to evolve slowly and on 3rd November failure extended to the neighbouring portion of rock with a total collapse of about 5000 cubic meters of rock. Failure analysis took advantage of an accurate characterization of geology, geometry and mechanical properties of the collapsed rock mass. Such analysis led to the conclusion that the failure has been caused by the concurrence of various factors, namely: - unfavourable dip and dip directions of stratification which daylight in the slope face; - possible reduction of the angle of shear resistance available along stratification especially as a consequence of intense rainfall and vibrations
Gelatinases and physical exercise: A systematic review of evidence from human studies
Matrix metalloproteinases (MMPs), particularly gelatinase A (MMP-2) and gelatinase B (MMP-9), as well as their tissue inhibitors (TIMP-1 and TIMP-2), are involved in the development of skeletal muscle tissue, in the repair process after muscle injury and in the adaptive modifications induced by physical exercise in skeletal muscle. This paper aims at reviewing results from human studies that investigated the role of gelatinases and their inhibitors in skeletal muscle response to acute physical exercise or training
Short-Term Prognosis of Juvenile Myocardial Infarction: Role of Plasma Viscosity
In our early research1 regarding the hemorheological pattern in
patients with acute myocardial infarction (AMI) with a mean
age of 61.45 + 10.99 years, we showed that the major hemorheological
parameters were almost normalized 2 weeks after
the acute event. In the last decade, we focused on hemorheological
parameters in juvenile myocardial infarction (JMI),
defined as AMI in patients aged 45 years, in the \u2018\u2018Sicilian
study on juvenile myocardial infarction\u2019\u2019
Spin Density Topology
Despite its role in spin density functional theory and it being the basic observable for describing and understanding magnetic phenomena, few studies have appeared on the electron spin density subtleties thus far. A systematic full topological analysis of this function is lacking, seemingly in contrast to the blossoming in the last 20 years of many studies on the topological features of other scalar fields of chemical interest. We aim to fill this gap by unveiling the kind of information hidden in the spin density distribution that only its topology can disclose. The significance of the spin density critical points, the 18 different ways in which they can be realized and the peculiar topological constraints on their number and kind, arising from the presence of positive and negative spin density regions, is addressed. The notion of molecular spin graphs, spin maxima (minima) joining paths, spin basins and of their valence is introduced. We show that two kinds of structures are associated with a spin-polarized molecule: the usual one, defined through the electron density gradient, and the magnetic structure, defined through the spin density gradient and composed in general by at least two independent spin graphs, related to spin density maxima and minima. Several descriptors, such as the spin polarization index, are introduced to characterize the properties of spin density critical points and basins. The study on the general features of the spin density topology is followed by the specific example of the water molecule in the 3 B 1 triplet state, using spin density distributions of increasing accuracy
A practical approach to estimate the degree of binder activity of reclaimed asphalt materials
Using Reclaimed Asphalt (RA) in new asphalt mixtures can reduce the amount of new material required thereby saving money and natural resources. In addition, asphalt mixtures with RA have shown comparable properties and performance to that generally associated with asphalt mixtures made with 100% virgin material. However, RA content in pavement surface layers is still limited due to specification and technical limitations. For higher contents, the aged RA binder must be analysed to accurately determine the requirements for virgin binders and additives while the degree of blending (DOB) between the RA binder and the virgin binder also needs to be quantified. This is not a simple process and generally designers assume one of two opposing theories associated with 100% (full blending) or 0% (“Black Rock”) DOB. This paper proposes a new approach to estimate a unique property of the RA known as the Degree of Binder Activity (DoA) as a function of the processing temperatures of the RA. The study showed positive results and indicated that this DoA approach can be used as a tool to better understand RA in order to improve the binder/blend design for recycled asphalt mixtures
Fluidity and cytosolic Ca2+ concentration of circulating polymorphonuclear leukocytes at baseline in some chronic and acute clinical conditions: review of our survey
Abstract. Objective: In this mini-review we describe the behavior of polymorphonuclear leukocyte (PMN) membrane fluidity and of PMN cytosolic Ca2+ concentration in some chronic and acute clinical conditions.
Methods: PMN membrane fluidity was evaluated employing the fluorescent probe Fura-2AM, and PMN cytosolic Ca2+ concentration was evaluated using the fluorescent probe TMA-DPH. Results: From the determination of these two parameters investigated on resting PMNs, an almost constant increase in PMN cytosolic Ca2+ concentration in chronic clinical conditions, such as vascular atherosclerotic disease with and without diabetes mellitus, essential hypertension, chronic kidney disease, and diabetes mellitus of both types, and a decrease in PMN membrane fluidity in acute clinical conditions, such as juvenile acute myocardial infarction and acute ischemic stroke, are evident. Conclusion: The possible reasons for this different behavior are analyzed on the basis of pathophysiological considerations
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