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C Angioni

Publications and source records attributed to C Angioni.

10 recordsLinked to original sources
PubMed2006

Prognostic factors in prosthetic rehabilitation of bilateral dysvascular above-knee amputee: is the stump condition an influencing factor?

AIM: The aim of this study was to evaluate the prognostic factors for rehabilitation outcome in bilateral dysvascular lower limb amputees, specifically to ascertain how the stump condition can influence the mobility outcome. METHODS: A retrospective study of 30 selected bilateral above-knee amputees for vascular disease was carried out. Barthel Index (BI) was given and stump condition was assessed at admission and at discharge. Influence of age, comorbidities and stump condition on effectiveness of BI was evaluated. Locomotor Capability Index (LCI) was performed at discharge. Influence of stump problems (pain, flexion, pain with flexion) on LCI was evaluated. RESULTS: At discharge, 25 patients were able to ambulate. Age and pathological conditions of stumps correlated negatively with BI effectiveness. LCI values were higher for patients with ideal stumps and lower for patients with combined stump pain and flexion deformities. Post hoc analysis showed that the principal factor negatively influencing the LCI score was the presence of stump flexion deformities. CONCLUSIONS: In our homogeneous group of bilateral amputees, age reduced the possibility of improving the level of autonomy. Good stump quality is one of the major determinants of mobility outcome. Efforts should be made to minimize stump complications. In particular, incorrect positioning of the stump, which is responsible for hip flexor retraction, should be avoided after surgery.

Activities of Daily Living↗
PubMed2006

Direction of impurity pinch and auxiliary heating in tokamak plasmas.

A mechanism of particle pinch for trace impurities in tokamak plasmas, arising from the effect of parallel velocity fluctuations in the presence of a turbulent electrostatic potential, is identified analytically by means of a reduced fluid model and verified numerically with a gyrokinetic code for the first time. The direction of such a pinch reverses as a function of the direction of rotation of the turbulence in agreement with the impurity pinch reversal observed in some experiments when moving from dominant auxiliary ion heating to dominant auxiliary electron heating.

Journal Article↗
PubMed2005

Experimental study of trapped-electron-mode properties in tokamaks: threshold and stabilization by collisions.

Trapped electron modes are one of the candidates to explain turbulence driven electron heat transport observed in tokamaks. This instability has two characteristics: a threshold in normalized gradient and stabilization by collisions. Experiments using modulated electron cyclotron heating in the ASDEX Upgrade tokamak demonstrate explicitly the existence of the threshold. The stabilization with increasing collisionality is evidenced by a strong decrease of the propagation of heat pulses, explained by a transition to ion temperature gradient driven transport. These results are supported by linear gyrokinetic calculations.

Journal Article↗
PubMed2003

Turbulent particle transport in magnetized plasmas.

Particle transport in magnetized plasmas is investigated with a fluid model of drift wave turbulence. An analytical calculation shows that magnetic field curvature and thermodiffusion drive an anomalous pinch. The curvature driven pinch velocity is consistent with the prediction of turbulence equipartition theory. The thermodiffusion flux is found to be directed inward for a small ratio of electron to ion pressure gradient, and it reverses its sign when increasing this ratio. Numerical simulations confirm that a turbulent particle pinch exists. It is mainly driven by curvature for equal ion and electron heat sources. The sign and relative weights of the curvature and thermodiffusion pinches are consistent with the analytical calculation.

Journal Article↗
PubMed2003

Density peaking, anomalous pinch, and collisionality in tokamak plasmas.

The existence of an anomalous particle pinch in magnetized tokamak plasmas is still questioned. Contradictory observations have been collected so far in tokamaks. Clear experimental evidence that density peaking in tokamak plasmas drops with increasing collisionality is provided for the first time. This phenomenon is explained by means of existing theoretical models based on the fluid description of drift wave instabilities, provided that such models include the dissipative effects introduced by collisions on the mentioned instabilities. These results reconcile the apparent contradictions found so far in the experiments.

Journal Article↗
PubMed2001

Long-pulse improved central electron confinement in the TCV tokamak with electron cyclotron heating and current drive.

Current profile tailoring by electron cyclotron heating (ECH) and current drive (ECCD) is used to improve central electron energy confinement in the TCV tokamak. Counter-ECCD on axis alone achieves this goal in a transient manner only. A stable scenario is obtained by a two-step sequence of off-axis ECH, which stabilizes magnetohydrodynamics modes, and on-axis counter-ECCD, which generates a flat or inverted current profile. This high-confinement regime, with central temperatures up to 9 keV (at a normalized beta(N) approximately 0.6), has been sustained for the entire duration of the heating pulse, or over 200 electron energy confinement times and 5 current redistribution times.

Journal Article↗
PubMed2000

Steady-state fully noninductive current driven by electron cyclotron waves in a magnetically confined plasma

A steady-state, fully noninductive plasma current has been sustained for the first time in a tokamak using electron cyclotron current drive only. In this discharge, 123 kA of current have been sustained for the entire gyrotron pulse duration of 2 s. Careful distribution across the plasma minor radius of the power deposited from three 0. 5-MW gyrotrons was essential for reaching steady-state conditions. With central current drive, up to 153 kA of current have been fully replaced transiently for 100 ms. The noninductive scenario is confirmed by the ability to recharge the Ohmic transformer. The dependence of the current drive efficiency on the minor radius is also demonstrated.

Journal Article↗
PubMed1998

Prognostic factors in rehabilitation of above knee amputees for vascular diseases.

PURPOSE: This study was undertaken to predict rehabilitation potential and prognostic factors of patients undergoing above knee amputation for vascular diseases. METHOD: In a prospective study on 144 patients consecutively admitted to our rehabilitation unit for above knee amputation, multiple regression analyses were used to assess the relationship between nine independent variables and a battery of outcome measures: the Rivermead Mobility Index (RMI) and Barthel Index (BI) effectiveness on discharge, length of hospital stay. Two multiple logistic regressions were performed, using as dependent variable the occurrence of good or partial autonomy in mobility, quantified as RMI scores. RESULTS: Advanced age was the most powerful prognostic factor influencing effectiveness expressed as both mobility (RMI) and BI. Patients aged < 65 years had a greater probability (odds ratio 2.92) of good autonomy in mobility than older patients. The absence of vascular impairment of the residual limb and timely admission to the rehabilitation hospital correlated positively with effectiveness of mobility. CONCLUSIONS: These findings indicate that relevant prognostic factors can be identified at the beginning of rehabilitation treatment.

Activities of Daily Living↗
PubMed1993

[Intraoperative ultrasonography in the diagnosis of liver metastasis from gastrointestinal neoplasms].

The authors illustrate their experience in the systematic use of intraoperative ultrasonography of the liver in patients undergoing surgery due to gastrointestinal cancer. The liver is the organ in which metastases from colorectal, stomach, pancreatic, and biliary cancer are most often localised. Between January 1991 and April 1992 95 patients underwent intraoperative ultrasonographic controls of the liver. In all cases the liver was studied using traditional image diagnosis: standard ultrasonography and CAT. On the basis of their experience the authors observed 12 cases negative for metastases using CAT and traditional ultrasonography which were positive using intraoperative ultrasonography, 2 cases which were positive for secondary hepatic lesions using traditional diagnostic tools but negative following histological tests guided by intraoperative ultrasonography. In the case of false negatives using traditional methods, those metastases revealed by intraoperative ultrasonography were above all located deep down and in segments which are difficult to explore, or were so small that they were not visible or palpable during intraoperative controls of the viscera. Intraoperative ultrasonography of the liver has been found to be a more sensitive test (97% of the best series) than standard ultrasonography (65%) or CAT (43%). Higher resolution due to the characteristics of the method is coupled with the possibility that intraoperative ultrasonography may be used to guide biopsies of the metastases revealed, thus allowing histological confirmation to be obtained: for this reason the risk of false positives is virtually zero.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗