1,357,445 research outputs found
La provincia delle Amazzoni : secondo la relazione del p. illuminato Giuseppe Coppi /
No full textIncludes Italian translations of excerpts from an article by Giuseppe Coppi."Estratto dal Bollettino della Società geografica italiana, marzo, 1885"--T.p. verso.Mode of access: Internet
Endogeneous magnetic reconnection and associated processes of relevance to fusion burning plasmas
No full textThe main characteristic of an endogenous magnetic reconnection process is that its driving
factor lays within the layer where a drastic change of magnetic field topology occurs. This
kind of process is shown to take place when a significant electron temperature gradient
is present in a magnetically confined plasma and when the evolving electron temperature
fluctuations are anisotropic r1s. Then r2s two classes of reconnecting modes are identified.
The localized class of mode involve a reconnected field B̃x of odd parity (as a function of
the radial variable), characteristic phase velocities and growth rates differently from the
commonly considered reconnecting modes associated with a finite effective resistivity. The
width of the reconnection layer remains significant even when large macroscopic distances
are considered. In view of the fact that there are plasmas in the Universe with considerable
electron thermal energy contents, the features of the considered modes can be relied upon
in order to produce generation or conversion of magnetic energy and high energy particle
populations through a sequence of mode-particle resonances r3s. With their excitation,
these modes acquire momentum in the direction of the main magnetic field component and
H
Tthe main body of the plasma column should recoil in the opposite direction r4s.
Endogenous modes associated with a finite electron temperature gradient are shown to be
sustained by the electron temperature heating rate due to the charged reaction products in
a fusion burning plasma r5s. In this case, the longitudinal thermal conductivity on selected
rational magnetic surfaces r5s is decreased, relative to its collisional value, by the effects of
reconnection.
The best agreement between theory and experiments concerning the onset of magnetic recon-
nection is (probably) represented by the theory of the resistive internal kink mode r6s. This
is reconsidered for regimes where the effects of local temperature gradients are important.
r1s B. Coppi and B. Basu, Phys. Lett. A, 382, 400 (2018).
r2s B. Coppi, Phys. Fluids, 8, 2273 (1965).
r3s B. Coppi et al., Nucl. Fus., 57, 7 (2017).
r4s B. Coppi, Nucl. Fus., 42, 1 (2002).
r5s B. Coppi et al., Nucl. Fus., 55, 053011 (2015).
r6s B. Coppi et al., Fiz. Plazmy, 2, 961 (1976)
Plasma Component of Self-gravitating Disks and Relevant Magnetic Configurations
No full textAstrophysical disks in which the disk self-gravity is more important than the gravity force associated with the central object can have significant plasma components where appreciable toroidal current densities are produced. When the vertical confinement of the plasma rotating structures that can form is kept by the Lorentz force rather than by the vertical component of the gravity force, the disk self-gravity remains important only in the radial equilibrium condition, modifying the rotation curve from the commonly considered Keplerian rotation. The equilibrium equations that are solved involve the vertical and the horizontal components of the total momentum conservation equations, coupled with the lowest order form of the gravitational Poisson's equation. The resulting poloidal field configuration can be visualized as a sequence [1] of Field Reverse Configurations, in the radial direction, consisting of pairs of oppositely directed current channels. The plasma density thus acquires a significant radial modulation that may grow to the point where plasma rings can form [2]. [1] B. Coppi, Phys. Plasmas, 12, 057302 (2005) [2] B. Coppi and F. Rousseau, to be published in Astrophys. J. (April 2006
Subclinical Vascular Damage: Current Insights and Future Potential
No full textAnna Vittoria Mattioli,1 Francesca Coppi,2 Antonio Manenti,1 Alberto Farinetti3 1Surgical, Medical and Dental Department of Morphological Sciences Related to Transplant, Oncology and Regenerative Medicine, University of Modena and Reggio Emilia, Modena, Italy; 2Cardiology Division, Policlinico di Modena, Modena, Italy; 3Department of Medical and Surgical Sciences for Children and Adults, University of Modena and Reggio Emilia, Modena, ItalyCorrespondence: Anna Vittoria MattioliSurgical, Medical and Dental Department of Morphological Sciences Related to Transplant, Oncology and Regenerative Medicine University of Modena and Reggio Emilia, Via del pozzo, 71, Modena, 41100, ItalyEmail [email protected]: The cardiovascular risk assessment must be carried out during all the different phases of life because the cardiovascular risk and the related prevention actions are dynamic and constantly evolving. As patients age, they change their exposure to various risk factors and accumulate comorbidities by changing their subjective cardiovascular risk, so it is necessary to undertake personalized early and preventive diagnostic actions. The main approach to asymptomatic vascular disease is based on primary prevention with the adoption of a healthy lifestyle. Indeed, lifestyle influences most of the traditional risk factors. In recent years, important differences between the sexes regarding cardiovascular risk factors have emerged and in particular, risk factors specific for female sex have been identified. Women are more likely to be categorized into lower risk categories for cardiovascular disease and, as a result, receive less lifestyle counseling than men, as well as less intensive prevention. This narrative review aims to analyze CVD risk prevention in asymptomatic atherosclerosis with a look at new emerging factors. In the end, we quickly analyzed the effects of the recent pandemic on lifestyle and cardiovascular risk and the potential negative effects in the long term.Keywords: prevention, risk factors, women, lifestyle, microbiota, pandemi
La biografia moltiplicata: Fausto Coppi, il diavolo e Gianni Brera
No full textAnalisi tematica e stilistica delle diverse e successive apparizioni a stampa (giornale, periodico, volumi) dell'opera che Gianni Brera scrive su Fausto Coppi, infine approdata al libro dal titolo "Coppi e il diavolo" (1981)
In vivo toxicity evaluation of a microsystem for polymyxin B oral administration
No full textAbstract Summary:
The aim of this study was to investigate in rats the toxicity of calcium alginate/chitosan microparticles, designed as a system to orally administer polymyxin B. Toxicity evaluation was performed after a single oral administration of PMB-loaded microparticles in comparison with unloaded microparticles and pure PMB.
Introduction:
The development of biodegradable microparticles with mucoadhesive properties and with a size of less than 5 μm could be very useful to promote the absorption of drugs with poor bioavailability via translocation of particles by M cells of Peyer’s patches (PP). These specialized cells staying over mucosa-associated lymphoid tissue (MALT), interspersed by enterocytes in the follicle associated epithelium (FAE), are able to transport via endocytosis a variety of microparticulate matter, macromolecules and microorganisms (bacteria, viruses, protozoae) from gut lumen to intraepithelial lymphoid cells (1). For this reason, the aim of this study was to investigate in rats the toxicity of calcium alginate/chitosan (Ca-ALG/CHT) microparticles, designed as a system to orally administer polymyxin B (PMB), antibiotic agent indicated in the treatment of serious infections caused by susceptible strains of Ps. Aeruginosa, H. influenzae, Escherichia coli, Aerobacter aerogenes, Klebsiella pneumoniae, when less potentially toxic drugs are ineffective or contraindicated. Biodegradable microparticles, prepared by spray-drying a sodium alginate solution containing PMB and subsequent reaction with Ca2+ ions and CHT, have been characterized in vitro and evaluated ex-vivo in previous studies (2). Toxicological evaluation was performed in this study in conformity with European Community regulations controlling experiments on live animals (CEE Council 89/609: Italian D.L.vo. 22-1-92 n. 116) after a single oral administration to male rats of PMB microparticles in comparison with unloaded microparticles and pure PMB.
Experimental Methods:
Thirty-six male rats (Wistar) from Harlan (Milan, Italy) of the same age, weighing about 200 g were housed alone in a metabolic cage with free access to water, maintained at constant room temperature (21°C). The animals were maintained at controlled temperature (21°C), humidity (50–60%) and day length (12 h) for 1 week before experiments. The toxicity study was performed after single administration to, respectively, 6 control rats and 6 assay rats for each sample: PMB water solution (60 mg/2 ml 300 mg/kg), PMB-loaded microparticle water suspension (500 mg/2 ml 60 mg/2 ml of pure PMB), unloaded microparticle water suspension (440 mg/ 2 ml). The control animals received 2 ml of distilled water. The administration was performed by oral gavage to fed/fasted rats. All treated animals were continuously monitored (mortality, behaviour, clinical signs) during the 24 h following the drug administration and urine samples were collected at 6 and 24 h. All surviving animals were killed 24 h after the treatment. After their death blood samples were collected and several organs were observed in situ to detect macroscopic abnormalities.
PMB levels were determined on urine samples and serum, obtained from blood, by a microbiological agar well diffusion method using E. coli as indicator strain.
Results and Discussion:
PMB solution administration to fasted rats: all animals died within 30’. The only abnormal physical sign noted during post-mortem examination was the presence of an intestinal haemorrhage (Fig. 2), probably causing the death.
PMB solution administration to fed rats: no animal died during the 24 h observation following the 300 mg/kg administration, but suffering signs like dyspnoea or haemorrhagic zones rounding the eyes were observed. At necropsy, all dosed rats had enlarged stomach (Fig. 1), probably causing breath problems. Therefore, after intragastric administration, PMB was lethal at a lower dose than that reported in the literature (LD50=790 mg/kg) especially in fasted animals.
Fig. 1 - Comparison between stomachs excised from a control (top side) and six treated rats.
Unloaded microparticles administration to fasted and fed rats: no animal died and no modification of animal behaviour and clinical signs were observed. No macroscopic abnormality in the organs examined after the animals were sacrificed was detected. These investigations thus seemed to indicate the safety of unloaded microparticles.
PMB-loaded microparticles administration to fed rats: all animals were still alive over 24 h without any appreciable behavioural signs of acute toxicity. At necropsy, all dosed rats had enlarged cecae/large intestines (Fig. 2). All the other organs were normal. Considering the PMB loading efficiency and PMB weight percentage in PMB-loaded microparticles, equivalent to 300 mg/kg, PMB-loaded microparticles appear more safety than free PMB.
Fig. 2 - Comparison between intestines excised from a control (top side), PMB-loaded microparticle treated rat (middle side) and free PMB treated rat (bottom side).
The agar well diffusion method chosen to test antimicrobial activity in biological fluids was considered suitable to detect very low PMB concentrations in urine and serum samples. In fact, plates related to samples collected from animals treated with PMB solutions showed pronounced and measurable zone of inhibition around each well; plates related to samples from animals treated with PMB-loaded microparticles showed less pronounced inhibition zone, whereas those related to rats treated with unloaded microparticles and controls showed no zone around any well at any time.
Conclusion:
Intragastric administration performed by oral gavage was considered suitable because no injuries was found to be related to the way of administration. The microbiological method is relatively simple and has sufficient precision and accuracy to be used to monitor drug levels.
Moreover, this study suggests that calcium alginate/chitosan microparticles were non-toxic and the intragastric administration of the microparticulate formulation determined a free PMB toxicity reduction.
References:
1) T.H. Ermak, P.J. Giannasca
Microparticle targeting to M cells.
Adv. Drug Del. Rev., 34, 261; 1998.
2) G. Coppi, V. Iannuccelli, N. Sala, M. Bondi
Alginate microparticles for polymixin B Peyer’s patches uptake.
J. Microencapsulation, 21, 829; 2004
Self-gravitating Disks and Plasma Structures Immersed in Them
No full textWhen considering axisymmetric differentially rotating plasma structures in the prevalent gravity of a central object these are found to be characterized by a sequence of current filaments and to develop a corresponding ring sequence configuration for the plasma. The same type of structure can be found when the self-gravity of a differentially rotating plasma component is no less important than the gravity of the central object. Then in addition to the vertical and horizontal equilibrium equations to be solved, Poisson's equation for the gravitational potential has to be dealt with. The fact that the vertical equilibrium is ensured by the vertical component of the Lorentz force due to the internal plasma currents (``Lorentz compression'') simplifies the problem considerably.
*Sponsored in part by the Universita' di Milano and by the U.S. DOE B. Coppi and F. Rousseau, Ap. J. 641 (1), 458 (2006)
Antonio Coppi, «vera gloria italiana»
No full textGianpaolo Fassino presenta in questo saggio la figura di Antonio Coppi. Originario di Andezeno, ma vissuto per la gran parte della sua vita a Roma, Antonio Coppi (1783-1870) è noto soprattutto per aver proseguito, fino al 1861, i settecenteschi Annali d’Italia di Lodovico Antonio Muratori. Per lungo tempo gli è stata impropriamente attribuita anche una piccola monografia di storia locale, le Memorie istoriche della Città di Chieri. Un’attenta rilettura di quest’opera ha consentito ora di espungere dalla bibliografia degli scritti di Coppi questo testo, frutto in realtà del lavoro di un altro erudito chierese, Giuseppe Broglia di Casalborgone
An efficient decomposition approach for surgical planning
No full textThis talk presents an efficient decomposition approach to surgical planning. Given a set of surgical waiting lists (one for each discipline) and an operating theater, the problem is to decide the room-to-discipline assignment for the next planning period (Master Surgical Schedule), and the surgical cases to be performed (Surgical Case Assignment), with the objective of optimizing a score related to priority and current waiting time of the cases. While in general MSS and SCA may be concurrently found by solving a complex integer programming problem, we propose an effective decomposition algorithm which does not require expensive or sophisticated computational resources, and is therefore suitable for implementation in any real-life setting.
Our decomposition approach consists in first producing a number of subsets of surgical cases for each discipline (potential OR sessions), and select a subset of them. The surgical cases in the selected potential sessions are then discarded, and only the structure of the MSS is retained. A detailed surgical case assignment is then devised filling the MSS obtained with cases from the waiting lists, via an exact optimization model.
The quality of the plan obtained is assessed by comparing it with the plan obtained by solving the exact integrated formulation for MSS and SCA. Nine different scenarios are considered, for various operating theater sizes and management policies. The results on instances concerning a medium-size hospital show that the decomposition method produces comparable solutions with the exact method in much smaller computation time
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