Novel concepts and nanostructured materials for thermionic-based solar and thermal energy converters.

Thermal and concentrated solar solid-state converters are devices with no moving parts, corresponding to long lifetimes, limited necessity of maintenance, and scalability. Among the solid-state converters, the thermionic-based devices are attracting an increasing interest in the specific growing sector of energy conversion performed at high-temperature. During the last 10 years, hybrid thermionic-based concepts, conceived to cover operating temperatures up to 2000 °C, have been intensively developed. In this review, the thermionic-thermoelectric, photon-enhanced thermionic emission, thermionic-photovoltaic energy converters are extensively discussed. The design and development processes as well as the tailoring of the properties of nanostructured materials performed by the authors are comprehensively described and compared with the advances achieved by the international scientific community.

Electronic structure modifications induced by increased molecular complexity: from triphenylamine to m-MTDATA.

The starburst π-conjugated molecule 4,4',4''-tris(N-3-methylphenyl-N-phenyl-amino)triphenylamine (C57H48N4, m-MTDATA), based on triphenylamine (TPA) building blocks, is widely used in optoelectronic devices due to its good electron-donor characteristics. The electronic structure of m-MTDATA was investigated for the first time in the gas phase by means of PhotoElectron Spectroscopy (PES) and Near Edge X-ray Absorption Fine Structure (NEXAFS) spectroscopy. The combination of Density Functional Theory (DFT) calculations with the experimental spectra provides a comprehensive description of the molecular electronic structure. Moreover, by comparing the results with previous TPA measurements, we could shed light on how the electronic structure evolves when the molecular size is increased. We found that the C 1s photoelectron spectra of m-MTDATA and TPA are similar, due to the balance of the counter-acting effects of the electronegativity of the N atoms and the delocalization of the amine lone-pair electrons. In contrast, the increased number of N atoms (i.e. N lone pairs) in m-MTDATA determines a three-peak feature in the outermost valence binding energy region with strong contributions by the N 2pz orbitals. We also obtained a decrease of the HOMO-LUMO gap for m-MTDATA, which points to improved electron donating properties of m-MTDATA with respect to TPA.

Electronic Structure Characterization of a Thiophene Benzo-Annulated Series of Common Building Blocks for Donor and Acceptor Compounds Studied by Gas Phase Photoelectron and Photoabsorption Synchrotron Spectroscopies.

The near-edge x-ray-absorption fine-structure (NEXAFS) and X-ray photoelectron spectroscopy (XPS) spectra of benzo[ b]thiophene (BBT) and dibenzothiophene (DBT) in the gas phase have been measured at the carbon K-edge and sulfur LII,III-edge regions. The assignment of the spectral features has been provided by theoretical calculations based on density functional theory (DFT) and its time-dependent generalization (TDDFT) in the linear response regime. Observed trends in computed C 1s and S 2p ionization potentials (IPs) have been rationalized in terms of both the inductive effects due to the presence of S and the increased π-electrons delocalization arising from the benzo-annulation process. The analysis of the NEXAFS carbon K-edge and sulfur LII,III-edge regions provided information on both low-lying delocalized virtual π orbitals, and higher-lying localized σ*(C-S) states. The evolution of the NEXAFS carbon K-edge spectral features along the series thiophene (T) and derivatives, BBT and DBT, is informative of a stabilizing effect due to increased aromaticity. This effect is however more pronounced in going from T to BBT compared to the introduction of a second annulated phenyl ring in DBT. The nature of the most intense sulfur LII,III-edge NEXAFS spectral features is instead conserved along the series reflecting thus the localized nature of the virtual states involved in the S 2p core-excitation process.

Endovascular management of a large hepatic artery aneurysm.

Visceral arteries aneurysms (VAA) are an increasingly interesting clinical entity due to their challenging diagnosis and treatment options. The more prevalent use and accuracy of enhanced imaging techniques such as ultrasonography and computed tomography have increased the frequency of diagnosis of aneurysmal degeneration of the visceral arteries. Despite there is no statistically significant difference in terms of overall mortality and post-operative complications between endovascular therapy and open repair, interventional strategies present a significantly lower length of stay and less invasiveness and should be preferred in elderly patients, or in case of co-morbidity and poor candidates for surgery. We herein describe the case of a 79-year-old male who presented a common hepatic artery aneurism (CHAA), involving aberrant visceral arteries anatomy.

Study of the electronic structure of short chain oligothiophenes.

The electronic structure of short-chain thiophenes (thiophene, 2,2'-bithiophene, and 2,2':5',2″-terthiophene) in the gas phase has been investigated by combining the outcomes of Near-Edge X-ray-Absorption Fine-Structure (NEXAFS) and X-ray Photoemission Spectroscopy (XPS) at the C K-edge with those of density functional theory (DFT) calculations. The calculated NEXAFS spectra provide a comprehensive description of the main experimental features and allow their attribution. The evolution of the C1s NEXAFS spectral features is analyzed as a function of the number of thiophene rings; a tendency to stabilization for increasing chain length is found. The computation of the binding energy allows to assign the experimental XPS peaks to the different carbon sites on the basis of both the inductive effects generated by the presence of the S atom as well as of the differential aromaticity effects.

S2p core level spectroscopy of short chain oligothiophenes.

The Near-Edge X-ray-Absorption Fine-Structure (NEXAFS) and X-ray Photoemission Spectroscopy (XPS) of short-chain oligothiophenes (thiophene, 2,2'-bithiophene, and 2,2':5',2″-terthiophene) in the gas phase have been measured in the sulfur L2,3-edge region. The assignment of the spectral features is based on the relativistic two-component zeroth-order regular approximation time dependent density functional theory approach. The calculations allow us to estimate both the contribution of the spin-orbit splitting and of the molecular-field splitting to the sulfur binding energies and give results in good agreement with the experimental measurements. The deconvolution of the calculated S2p NEXAFS spectra into the two manifolds of excited states converging to the LIII and LII edges facilitates the attribution of the spectral structures. The main S2p NEXAFS features are preserved along the series both as concerns the energy positions and the nature of the transitions. This behaviour suggests that the electronic and geometrical environment of the sulfur atom in the three oligomers is relatively unaffected by the increasing chain length. This trend is also observed in the XPS spectra. The relatively simple structure of S2p NEXAFS spectra along the series reflects the localized nature of the virtual states involved in the core excitation process.

Successful endovascular treatment of a 13 cm abdominal aortic aneurysm. Case report.

There is increasing evidence in the literature that endovascular aneurysm repair is the first-line approach for most of abdominal aortic aneurysms (AAAs). Furthermore aortouniiliac stent graft placement is, in high risk patients or during emergency setting, a safe procedure over the mid- and long-term period and compares well with the results of bifurcated stent grafts. We present a case of a 66 -year-old gentleman, with pneumothorax after therapeutic thoracentesis and a giant AAA, successfully treated with an aortomonoiliac stent grafting and femoro-femoral crossover bypass.

Chest pain due to Pinch-off syndrome: radiological findings and endovascular rescue.

Port-a-cath is widely used as a route for administration of drugs in hematology and oncology patients and, recently, has been adapted also for hemodialysis patients. Major complications include infection, thrombosis, arrhythmia, and embolization. The Pinch-off-syndrome (POS) means the clavicle and the first rib compress the long-term central venous catheter. The reported incidence rate ranges from 1.4% to 4.1%. This syndrome can be recognized on chest radiography by observing a thinning of the catheter lumen through the passage between the clavicle and the first rib. Catheter fracture is a rare but potentially life-threatening complication that must be recognized and treated promptly. Management of dislodged ports includes percutaneous transcatheter retrieval, open thoracotomy retrieval and oral anticoagulant therapy. Among these techniques, percutaneous transcatheter retrieval is an easy, safe and efficient method. We report the successful percutaneous endovascular retrieval of dislodged intracardiac catheter, separated from its port, in a 58 year-old male patient who presented with chest pain.

Cavitation dynamics of laser ablation of bulk and wire-shaped metals in water during nanoparticles production.

Although the first nanoseconds to microseconds rule the resulting process yield of laser ablation in liquid, a comprehensive view involving combination of time-resolved measurement techniques is still lacking. In this paper, fundamental aspects of laser ablation of metals in water during the production of nanoparticles are discussed. Three fast diagnostic methods have been applied simultaneously. These are Optical Emission Spectroscopy for the plasma characterization, fast shadowgraph for plasma and cavitation bubble dynamics and laser scattering for the mechanisms of delivery of the produced materials in the liquid. Moreover, in order to validate the discussion, the effect on cavitation dynamics of the ablation of bulk and wire-shaped targets has been investigated together with the relative nanoparticles production yield. Unusual arrow-bow ejection phenomena between the cavitation bubble and the wire result in suppressed material back-deposition, causing efficient ejection of ablated matter into the liquid. The presented nanosecond and microsecond-resolved analysis allows estimating the timescale and role of the basic mechanisms involved in laser ablation in liquids as well as the thermodynamic characteristics of the processes.

Sentinel node detection with imaging probe.

A once-square-inch-field-of-view mini gamma camera, whose first prototype was built by us in 1998 and given the name imaging probe (IP), was initially employed in sentinel lymph node (SLN) detection. This is probably the best way of learning how to use it. In the present work IP was used for SLN localization by a medical team that, after having been trained by the group of nuclear physicians of "La Sapienza" University who designed and first used the detector, used IP at their own hospital to 1) acquire experience for future use during surgery (a cooperative project on IP-radioguided orthopedic surgery is ongoing) and 2) start multicenter trials with IP. The SLN was identified and localized with IP and a non-imaging probe, Neoprobe 2000, in six patients with breast cancer who underwent lymphoscintigraphy for SLN biopsy. The operators who used Neoprobe and IP were blinded to each other's findings and to the results obtained with the large-field-of-view Anger camera that was used for lymphoscintigraphy. The Anger camera, IP and Neoprobe detected seven SLNs in six patients. The mean detection time was 2 mins 6 s (standard deviation (SD) 26 s) with IP, and 2 mins 18 s (SD 47 s) with Neoprobe 2000. The SLN that was most difficult to find was detected in 2 mins 56 s with IP and 3 mins 45 s with Neoprobe. The operators' subjective impression of having detected the SLN was "absolutely sure" for 7/7 nodes with IP and "absolutely sure" for 5/7 nodes with Neoprobe.

[Alcohol treatment of hydatid cyst in a case of old hydatidosis with hepatic skip]. / Alcolizzazione di lesione idatidea in un caso clinico inveterato di echinococcosi con salto epatico.

Hydatidosis is related to parasitical etiology, linked to Echinococcus granulosis and Echinococcus multilocularis. The authors describe an uncommon clinical case of old hydatidosis in an 80-year old woman, presenting hepatic skip , with localization to the right lung and kidney and burrowing to the posterior abdominal wall. Because of the patient's lack of compliance, percutaneous treatment with alcohol of the lumbar lesion with 95% ethanol is carried out under echographic guide, to improve quoad valetudinem prognosis. The authors indicate that the method target are: 1) multiple relapse lesions; 2) complicated anatomie area; 3) multiltle cyst; 4) marginal lesions. Moreover, this method shows important advantages such as be possibility of repetition, low invasivity, high patient's compliance, low rate of shock and dissemination and finally low cost.

[Treatment with thymopentine of chronic bronchitis in elderly patients during seasonal prophylaxis]. / Trattamento con timopentina della bronchite cronica del paziente anziano in corso di profilassi stagionale.

The design of the present study permits to analyse the efficacy of thymopentin treatment in seasonal prophylaxis of chronic bronchitis in elderly patients. The immunologic and symptomatic responses were observed and evaluated. The elderly female patients, observed in the present study, were followed for six months after treatment with thymopentin.

Role of purinergic system in tracheobronchial reactivity of healthy and bronchopathic subjects.

We have investigated the effect of inhaled adenosine on bronchomotor tone in 16 healthy and 24 allergic and non-allergic bronchopathic subjects. We determined the inhaled adenosine dose-response curves after no treatment and after treatment with aminophylline (240 mg in 10 min), reproterol (90 mcg in 2 min) and salbutamol (100 mcg in 2 min) administered intravenously 15 min before adenosine and reproterol (500 mcg) and salbutamol (200 mcg) administered by inhalation from a metered aerosol 30 min before adenosine on separate days. Without prior treatment, inhaled adenosine caused bronchoconstriction in both groups of subjects (normal, and atopic and non-atopic asthmatic ones), but the peripheral airways revealed only a moderate change in normal subjects. Aminophylline caused a greater inhibition of adenosine bronchoconstriction than did reproterol. These results suggest that inhaled adenosine bronchoconstriction involved purinergic transmission and that it is mediated via a P1/Ri (A-1/R1) receptor. Aminophylline is a potent antagonist at purinoceptor level. Reproterol inhibits bronchoconstriction by a mechanism independent of its effect on beta-adrenergic receptors. Because salbutamol, i.e. a beta 2-agonist bronchodilator, did not inhibit adenosine-induced bronchoconstriction (or very nearly so), our results support the view that reproterol antagonizes P1/Ri (A1/R1) tracheobronchial receptors.