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Biomedical subjects

G Ferrari

Publications and source records attributed to G Ferrari.

At least 37 records · Page 2Linked to original sources
PubMed2004

Fault detection in a real-time monitoring network for water quality in the lagoon of Venice (Italy).

In the context of monitoring water quality in natural ecosystems in real time, on-line data quality control is a very important issue for effective system surveillance and for optimizing maintenance of the monitoring network. This paper presents some applications of recursive state-parameter estimation algorithms to real-time detection of signal drift in high-frequency observations. Two continuous-discrete recursive estimation schemes, namely the Extended Kalman Filter and the Recursive Prediction Error algorithm, were applied to assuring the quality of the dissolved oxygen (DO) time series, as obtained from the Lagoon of Venice (Italy) during August 2002, through the real-time monitoring network of the Magistrato alle Acque (the Venice Water Authority). Results demonstrate the effectiveness of the methodology in early detection of a probable drift in the DO signal. Comparison of these results with those obtained from the application of a related recursive scheme (a Dynamic Linear Regression procedure) suggests the strong benefits of approaching the problem of on-line data quality control with several (not merely a single) independent such estimation methods.

Algorithms↗
PubMed2003

Precision frequency measurement of visible intercombination lines of strontium.

We report the direct frequency measurement of the visible 5s(2) 1S0-5s5p 3P1 intercombination line of strontium that is considered a possible candidate for a future optical-frequency standard. The frequency of a cavity-stabilized laser is locked to the saturated fluorescence in a thermal Sr atomic beam and is measured with an optical-frequency comb generator referenced to the SI second through a global positioning system signal. The 88Sr transition is measured to be at 434 829 121 311 (10) kHz. We measure also the 88Sr-86Sr isotope shift to be 163 817.4 (0.2) kHz.

Journal Article↗
PubMed2003

Mutations of ANT1, Twinkle, and POLG1 in sporadic progressive external ophthalmoplegia (PEO).

To verify the impact of mutations in ANT1, Twinkle, and POLG1 genes in sporadic progressive external ophthalmoplegia associated with multiple mitochondrial DNA (mtDNA) deletions, DNA samples from 15 Italian and 12 British patients were screened. Mutations in ANT1 were found in one patient, in Twinkle in two patients, and in POLG1 in seven patients. Irrespective of the inheritance mode, screening of these genes should be performed in all patients with progressive external ophthalmoplegia with multiple mtDNA deletions.

Adenine Nucleotide Translocator 1↗
PubMed2003

A study of the progress of the Aujeszky's disease control programme in Italy using survival analysis.

A 3-year study (1997-2000) was performed on 294 swine herds from Italy, where a National Programme of Control of Aujeszky's Disease (AD) based on compulsory vaccination has been operative since 1997. Aim of the study was to evaluate the progress of this control programme using a survival approach applied to gE-seropositive herds at the beginning of the programme. The cumulative proportion of herds still gE-seropositive at the end of the study was 0.57. No significant difference in the probability of becoming gE-seronegative during the study period was found between herds of different type (breeding versus farrow-to-finish) whereas significant differences were seen between herds from different areas. The Cox's proportional hazards regression, performed on data from 79 herds, showed that the only risk factor significantly associated with a higher probability of becoming gE-seronegative is again the geographical location. Other risk factors considered in the analysis were: type of enterprise, type of replacement of animals, herd size, pig and pig herds densities around the farm, distance from the nearest pig herd and year of beginning of the vaccination with a gE-deleted vaccine.

Animals↗
PubMed2003

Mirtazapine in the treatment of panic disorder: an open-label trial.

The aim of this open label trial was to evaluate mirtazapine tolerability and effectiveness in controlling symptomatology of patients with panic disorder. Forty-five patients with panic disorder, with or without agoraphobia, 11 of them with a comorbid diagnosis of major depression, were included. Patients were assessed with a structured psychiatric interview and their symptomatology evaluated with specific psychometric scales. Three study participants dropped out due to adverse events. Mirtazapine was administered at an established dose of 30 mg daily for 3 months. Patients were assessed at weeks 2 and 4, and then at monthly intervals. All psychometric measures showed statistically significant reductions in total scores at the rated time points, with a pronounced decline in number and intensity of panic attacks and anticipatory anxiety throughout the study. Mirtazapine was well tolerated as signified by the low discontinuation rate (6.3%), and all patients showed a significant symptomatic improvement. The improvement did not appear to be linked to the concurrent presence of a depressive illness.

Adult↗
PubMed2003

Can breast-feeding protect against schizophrenia? Case-control Study.

BACKGROUND: Human milk, unlike formula feeds, contains long-chain polyunsatured fatty acids, such as docosahexaenoic acid and arachidonic acid which are essential in the development of the central nervous system. If human milk is the optimal food for brain development, and if schizophrenia is a neurodevelopment disorder, might people who become schizophrenic in adult life be less likely to have been breast-fed? AIMS: To compare the incidence and length of breast-feeding in patients, siblings and normal controls and to examine the relationship between the duration of breast-feeding and age at onset of schizophrenia. METHOD: 113 schizophrenic patients were recruited, as were 140 siblings of the patients and 113 nonschizophrenic controls. The breast-feeding history of the patients, their siblings and controls was obtained through interviews with the mothers of the patients and controls. RESULTS: There were no significant differences between groups in the incidence of breast- feeding. The duration of breast-feeding was positively correlated with the age at onset of illness (r = +0.25, p < 0.02). CONCLUSION: Breast-feeding is no less common in those who develop schizophrenia in later life. However, breast milk might postpone the onset of the illness in schizophrenic patients.

Adult↗
PubMed2003

A hybrid mock circulatory system: development and testing of an electro-hydraulic impedance simulator.

Mock circulatory systems are used to test mechanical assist devices and for training and research purposes; when compared to numerical models, however, they are not flexible enough and rather expensive. The concept of merging numerical and physical models, resulting in a hybrid one, is applied here to represent the input impedance of the systemic arterial tree, by a conventional windkessel model built out of an electro-hydraulic (E-H) impedance simulator added to a hydraulic section. This model is inserted into an open loop circuit, completed by another hybrid model representing the ventricular function. The E-H impedance simulator is essentially an electrically controlled flow source (a gear pump). Referring to the windkessel model, it is used to simulate the peripheral resistance and the hydraulic compliance, creating the desired input impedance. The data reported describe the characterisation of the E-H impedance simulator and demonstrate its behaviour when it is connected to a hybrid ventricular model. Experiments were performed under different hemodynamic conditions, including the presence of a left ventricular assist device (LVAD).

Computer Simulation↗
PubMed2003

Modelling of cardiovascular system: development of a hybrid (numerical-physical) model.

Physical models of the circulation are used for research, training and for testing of implantable active and passive circulatory prosthetic and assistance devices. However, in comparison with numerical models, they are rigid and expensive. To overcome these limitations, we have developed a model of the circulation based on the merging of a lumped parameter physical model into a numerical one (producing therefore a hybrid). The physical model is limited to the barest essentials and, in this application, developed to test the principle, it is a windkessel representing the systemic arterial tree. The lumped parameters numerical model was developed in LabVIEW environment and represents pulmonary and systemic circulation (except the systemic arterial tree). Based on the equivalence between hydraulic and electrical circuits, this prototype was developed connecting the numerical model to an electrical circuit--the physical model. This specific solution is valid mainly educationally but permits the development of software and the verification of preliminary results without using cumbersome hydraulic circuits. The interfaces between numerical and electrical circuits are set up by a voltage controlled current generator and a voltage controlled voltage generator. The behavior of the model is analyzed based on the ventricular pressure-volume loops and on the time course of arterial and ventricular pressures and flow in different circulatory conditions. The model can represent hemodynamic relationships in different ventricular and circulatory conditions.

Coronary Circulation↗
PubMed2003

[Primary leiomyoma of the lung, with clear-cell features and admixed alveolar spaces: description of a case presenting with pneumothorax].

OBJECTIVE: To report about a primary leiomyoma of the lung, with clear cell features and with admixed alveolar epithelium. RESULTS AND CONCLUSIONS: The patient, a 18-year-old female, non smoker, presented with a well-delimited pleuro-pulmonary mass, 6,5 cm across, located in the right upper lobe. The mass was discovered 5 years previously, following an episode of spontaneous pneumothorax; initially interpreted as an intralobar pulmonary sequestration, it was subsequently removed due to a small dimensional increase. A gynaecological examination, a thoracic CT-scan obtained 2 years after operation, and a recent abdomino-pelvic echography were negative. The patient is alive and well 7 years after surgery. Microscopically, the lesion was well delimited and it was punctuated by multiple cysts of variable dimensions, covered by bland cubic cells. The solid part of the lesion was composed by oval, clear cells, merging with fusiform elements with densely eosinophilic cytoplasm. Significant atypia, mitoses and necrosis were absent. Immunohistochemically, both oval and spindle cells were strongly positive for vimentin, smooth muscle actin, desmin and h-caldesmon, negative for cytokeratin, EMA, CD-34, CD-10, CD-117, HMB-45, TTF-1, BCL-2, GFAP, calretinin, chromogranin, estrogen and progesterone receptors. Cells covering the cystic spaces were positive for cytokeratin, TTF-1 and EMA, negative for all the other antibodies tested. Smooth muscle proliferations of the lung are briefly discussed, together with the most important problems in differential diagnosis.

Adolescent↗
PubMed2002

Collisional properties of ultracold K-Rb mixtures.

We determine the interspecies s-wave triplet scattering length a(3) for all K-Rb isotopic mixtures by measuring the elastic cross section for collisions between 41K and 87Rb in different temperature regimes. The positive value a(3)=+163(+57)(-12)a(0) ensures the stability against collapse of binary (41)K- (87)Rb Bose-Einstein condensates. For the fermion-boson mixture (40)K- (87)Rb, we obtain a large and negative scattering length which implies an efficient sympathetic cooling of the fermionic species down to the degenerate regime.

Journal Article↗
PubMed2002

Formation of a matter-wave bright soliton.

We report the production of matter-wave solitons in an ultracold lithium-7 gas. The effective interaction between atoms in a Bose-Einstein condensate is tuned with a Feshbach resonance from repulsive to attractive before release in a one-dimensional optical waveguide. Propagation of the soliton without dispersion over a macroscopic distance of 1.1 millimeter is observed. A simple theoretical model explains the stability region of the soliton. These matter-wave solitons open possibilities for future applications in coherent atom optics, atom interferometry, and atom transport.

Journal Article↗
PubMed2002

The non-immunosuppressive immunophilin ligand GPI-1046 potently stimulates regenerating axon growth from adult mouse dorsal root ganglia cultured in Matrigel.

We used explant cultures of adult mouse dorsal root ganglia with spinal nerve attached growing in Matrigel to assess the effects of the non-immunosuppressive immunophilin ligand GPI-1046 [Snyder et al. (1998) TIPS 19, 21-26] on the growth rate of regenerating sensory axons and found a potent stimulation of axon growth. In these explant cultures, naked, unfasciculated axons emerge from the cut end of the spinal nerve and continue to grow in the Matrigel for up to eight days [Tonge et al. (1996) Neuroscience 73, 541-551]. Some axons are entirely smooth whilst others show prominent varicosities. Some of the former express the phosphorylated neurofilament epitope recognised by monoclonal antibody RT97, a marker for large calibre, myelinated axons, whilst the latter express calcitonin gene-related peptide, predominantly a marker for unmyelinated, and small diameter myelinated sensory axons. Many of the axons in these cultures also express the low-affinity neurotrophin receptor p75. GPI-1046 has been shown to have striking stimulatory effects on embryonic primary sensory axons growing in vitro and it was therefore of interest to see whether it could also enhance regenerating sensory axon growth from the adult ganglia in our cultures. GPI-1046 potently stimulated axon growth in our cultures in a dose-dependent manner. The stimulatory effect was not dependent on the class of sensory axon. These observations show that GPI-1046 is a potent stimulator of regenerating axons from adult, primary sensory neurones. The cellular site of action of GPI-1046 is unknown. To distinguish between a direct effect of the drug on neurones and an indirect effect we compared the effects of GPI-1046 on explant and dissociated cultures. In confirmation of previous results, we found that GPI-1046 potently stimulated axon outgrowth from explants of embryonic chick dorsal root ganglia. However, the drug was without effect on dissociated embryonic dorsal root ganglion neurones, suggesting that non-neuronal cells are important for axon growth stimulation.

Animals↗
PubMed2002

Study of systolic pressure variation (SPV) in presence of mechanical ventilation.

Systolic pressure variation (SPV) and its components (dUp and dDown) have been demonstrated to be of interest in assessing preload in mechanically ventilated patients. The aim of this paper is to analyse the sensitivity of these variables to preload and volemic changes during mechanical ventilation in different conditions of the cardiovascular system. Computer simulation experiments have been done using a modular lumped parameter model of the cardiovascular system. The effect of mechanical ventilation has been reproduced operating on intrathoracic pressure. Experiments have been performed varying preload through filling pressure. Sensitivity of SVP dUp and dDown is described varying separately left ventricular elastance (Ev), systemic arterial resistance (Ras) and systemic arterial compliance (Cas). The sensitivity of SPV and dDown to preload and filling pressure is appreciable for high values of Ev and for a wide variation of Ras. Preliminary clinical data concerning the three parameters show good correlation with simulation results.

Blood Pressure↗
PubMed2002

Surface characterization and debris analysis of ceramic pairings after ten million cycles on a hip joint simulator.

This study was aimed at characterizing the ceramic wear particles produced during tests on a hip joint wear simulator of up to 10 million cycles. Alumina and alumina-zirconia composites were studied as commercial or potential hip joint products respectively. No ceramic particles could be observed, even after a careful isolation procedure. This confirms the low wear rate found for these materials in previous works (of the order of tenths of milligrams per million cycles). Surface characterization was conducted by means of scanning electron microscopy. It confirms the low wear regime of ceramic pairings and allows ceramic wear debris morphology to be defined. The effect of microstructure on surface wear is discussed.

Aluminum Oxide↗
PubMed2001

Preoperative localization of indeterminate pulmonary nodules before videothoracoscopic resection.

BACKGROUND: The management of a solitary pulmonary nodule is the subject of debate and minimally invasive diagnostic approaches have low sensitivity for small peripheral nodules. We discuss the role of video-assisted thoracoscopic surgery (VATS) in the management of solitary pulmonary nodules (SPNs) < or = 1 cm performed with a preoperative computed tomography-guided wire localization. METHODS: Thirty-five selected patients underwent VATS resection for SPN, with localization by guide wire before surgery. RESULTS: Seven patients, after VATS exploration, underwent thoracotomy because of pleuropulmonary adhesions, depth or dimensions. Histological diagnosis was obtained in all procedures; there was no postoperative morbidity or morbidity. CONCLUSION: Preoperative computed tomography hook-wire localization is a suitable strategy for peripheral nodules < or = 1 cm in diameter.

Humans↗
PubMed2001

CD8 CTL responses in vaccines: emerging patterns of HLA restriction and epitope recognition.

We evaluated MHC-class I-restricted CTL responses induced by HIV-1 clade B-based vaccines in nine HIV-1 seronegative vaccine recipients with regard to their patterns of HLA restriction and epitope recognition. We found that seven of nine volunteers developed detectable CTL reactivities against novel epitopes within the HIV-1 Env and Gag proteins. Although four of nine subjects were HLA-A*0201, none of the cellular responses was restricted in the context of this allele. The type of responses observed in this sampling of vaccines appeared similar to those reported during primary infection and among long term non-progressors, with three out of nine subjects recognizing HLA-B27 or HLA-B17(57)-restricted epitopes. Although the majority of CTL responses were directed against novel epitopes, these effectors were still able to mediate cross-clade reactivities.

AIDS Vaccines↗
PubMed2001

Bose-Einstein condensation of potassium atoms by sympathetic cooling.

We report on the Bose-Einstein condensation of potassium atoms, whereby quantum degeneracy is achieved by sympathetic cooling with evaporatively cooled rubidium. Because of the rapid thermalization of the two different atoms, the efficiency of the cooling process is high. The ability to achieve condensation by sympathetic cooling with a different species may provide a route to the production of degenerate systems with a larger choice of components.

Journal Article↗