LIBO is a proton accelerator that operates at
3
GHz
, the same frequency as the one adopted in the about 7500 electron linacs used for radiotherapy all over the world. Such a high frequency was ...chosen to obtain a large gradient (on average more than
10
MV/m
), and thus a short linac (about
15
m
) to boost the energy of the protons, extracted at about
60
MeV
from a cyclotron, up to the
200
MeV
needed for the treatment of deep-seated tumours.
This paper describes the design study of the full
3
GHz
Side Coupled Linac (modular structure, nine modules) and the construction and tests of the LIBO prototype (first module), which was built to accelerate protons from 62 to
74
MeV
with an RF peak power of
4.4
MW
. The items discussed are the beam dynamics parameters of the module (longitudinal and transverse acceptances), the constructional elements and procedures, the accuracies of the various mechanical elements, the cooling system, the RF tuning, the RF measurement and the RF power tests. These tests showed that, after a short conditioning time, the gradient in each of the four tanks of the module could reach
28.5
MV/m
, much larger than the nominal project value
(15.8
MV/m)
. The last section of the paper describes the successful acceleration tests performed at the Laboratori Nazionali del Sud of INFN in Catania with a solid-state
3
GHz
modulator lent by IBA.
In the present study we investigated whether the precentral component (N30) of short somatosensory evoked potentials (SEPs) to median nerve stimulation may be modified by peripheral neuromuscular ...blocking agent in patients affected by rigidity. We, therefore, recorded SEPs in nine Parkinson's disease (PD) patients and in seven psychotic patients affected by neuroleptic malignant syndrome (NMS), all showing severe rigidity. Each patient group was studied before and after the placebo, and before and after an atracurium besilate bolus of 0.05 mg/kg, in a single recording session. At the time of the test the PD patients had not taken any antiparkinsonian therapy for at least 48 h. The same recordings were also taken on nine neurologically normal subjects undergoing surgical procedures. Atracurium administration produced a remarkable amplitude increase of the major precentral component (N30) of SEPs. An atracurium-induced N30 amplitude increase was observed in both PD patients (from 2.41 to 4.07 microV) and NMS psychotic patients (from 2.03 to 3.97 microV), whereas there was a minor N30 amplitude increase in healthy subjects (from 3.53 to 4. 10 microV). The N30 latency was unaffected. Amplitude and latency of the major parietal SEPs component (N20) was unchanged in the three groups studied. Our results lead to the conclusion that a neuromuscular blocking agent is capable of increasing the N30 amplitude in patients affected by severe rigidity, exclusively reducing their muscular tone without interfering with the central dopaminergic system. Thus, a "peripheral gating" of sensory input to the supplementary motor area due to rigidity may play a relevant role in producing the N30 amplitude decrease described in patients affected by degenerative or pharmacologically induced parkinsonism. The reduction of rigidity could be the mechanism by which dopamine may increase the precentral N30 amplitude in parkinsonian syndromes.
X‐ray fluorescence (XRF) analyses of metals, glasses and enamels from the Corona Ferrea, or Iron Crown, of Monza are reported. The method followed to obtain quantitative analysis of metal alloys was ...based on comparison with standards and it is framed on the more general problem of XRF quantitative analysis of irregularly shaped objects with a portable instrument. Preliminary radiocarbon dating results are also reported.
The properties and possible applications of a very intense source of monochromatic X-rays, tunable in the 1–100 keV range, obtained by coupling a low energy (2–4 MeV) high current proton accelerator ...with an irradiation chamber provided with a multiple target system and collimator are discussed. The properties of the source are presented in terms of intensity, monochromaticity, polarizability and time structure. Fields where such a source can be employed are discussed, namely PIXE-induced XRF, X-ray photoemission spectroscopy, generation of soft X-rays, radiographic applications in archeometry and medical radiography with monoenergetic radiation.
Estrogen and androgen hormones were studied in the plasma and cerebrospinal fluid (CSF) of five patients affected by pseudotumor cerebri (PTC). Six men and six women without cerebral or endocrine ...diseases were selected as controls. Androstenedione (A), testosterone (T), 17-hydroxyprogesterone (17OH-P), E1 and E2 were measured in plasma and CSF in baseline conditions and following 1 month prednisone therapy (2 mg/die, per os) using RIA following chromatographic separation on celite microcolumns. Men and women affected by PTC show increased CSF E1 levels and marked decreased CSF A levels, with respect to controls. In plasma, on the contrary, normal values of these parameters were observed in PTC. In normal subjects A/E1 ratio shows the same values in plasma and CSF, suggesting for the two hormones analogous feasibility to cross the blood brain barrier. In PTC patients A/E1 ratio is comparable to controls in plasma, but lower in CSF as a result of decreased A and increased E1 contents. The CSF imbalance between A and E1 attenuates but does not disappear after treatment. No correlation is found between pressure levels and steroid pattern both in baseline condition or after one month of treatment. In conclusion, our results demonstrate that PTC is not only associated with increased CSF E1 levels, as previously suggested, but, above all, with decreased CSF A levels and this hormonal impairement seems to be confined to the CSF compartment and not observed in plasma. These data do not lead to any definitive conclusion about the role of altered CSF estrogen and androgen levels in PTC pathogenesis.
We studied N20 and N30 waves of Somatosensory Evoked Potentials from median nerve stimulation in different pharmacological conditions. N30 wave amplitude was decreased in 33 parkinsonians without ...therapy in comparison with a group of age-matched normal subjects. In a group of 19 parkinsonians, N30 wave amplitude was significantly augmented during apomorphine infusion and less evidently, but still significantly, during chronic 1-dopa therapy. The administration of an oral dose of haloperidol in 11 normals did not affect significantly the studied parameters. The infusion of apomorphine in 6 psychotic patients with extrapyramidal symptoms secondary to long-term treatment with neuroleptics, determined, together with a clear-cut clinical amelioration, a significant increase of N30 amplitude and N30/N20 ratio. Possible pathophysiological hypothesis of such electrophysiological modifications are discussed.
In the present study we investigated whether the precentral component (N30) of short somatosensory evoked potentials (SEPs) to median nerve stimulation may be modified by peripheral neuromuscular ...blocking agent in patients affected by rigidity. We, therefore, recorded SEPs in nine Parkinson's disease (PD) patients and in seven psychotic patients affected by neuroleptic malignant syndrome (NMS), all showing severe rigidity. Each patient group was studied before and after the placebo, and before and after an atracurium besilate bolus of 0.05 mg/kg, in a single recording session. At the time of the test the PD patients had not taken any antiparkinsonian therapy for at least 48 h. The same recordings were also taken on nine neurologically normal subjects undergoing surgical procedures. Atracurium administration produced a remarkable amplitude increase of the major precentral component (N30) of SEPs. An atracurium-induced N30 amplitude increase was observed in both PD patients (from 2.41 to 4.07 mu V) and NMS psychotic patients (from 2.03 to 3.97 mu V), whereas there was a minor N30 amplitude increase in healthy subjects (from 3.53 to 4.10 mu V). The N30 latency was unaffected. Amplitude and latency of the major parietal SEPs component (N20) was unchanged in the three groups studied. Our results lead to the conclusion that a neuromuscular blocking agent is capable of increasing the N30 amplitude in patients affected by severe rigidity, exclusively reducing their muscular tone without interfering with the central dopaminergic system. Thus, a "peripheral gating" of sensory input to the supplementary motor area due to rigidity may play a relevant role in producing the N30 amplitude decrease described in patients affected by degenerative or pharmacologically induced parkinsonism. The reduction of rigidity could be the mechanism by which dopamine may increase the precentral N30 amplitude in parkinsonian syndromes.
Contingent negative variation (CNV) recordings were performed in 55 healthy volunteers under stress condition (experimentally induced pain). A total of 20 subjects were included in the control group ...(no painful administration). In the tested group (n = 35) the painful stimulus was delivered before S1, between S2 and S1, and before S2. In the control group there were no changes in CNV parameters. Conversely, among the tested group a positive correlation was found between CNV values (whenever the painful stimulus was administered before S1 as well as before S2) and the highest scores in the State Trait Anxiety Inventory X 2 test. In addition, all individuals displayed the appearance of a positive deflection with a latency of about 300 ms from S2 when the experimental stress was given before S2. Furthermore, the postimperative negative variation (PINV) appeared in 13 out of 35 subjects. There was a strong correlation between the latter electrophysiological phenomenon and the Nowlis test. Our findings suggest that CNV study is useful for the investigation of personality traits in human beings under stress conditions.
Over a period of time, the authors have studied a case of subacute sclerosing panencephalitis (SSPE), by means of brainstem auditory evoked potentials (BAEPs). The observed abnormalities of the ...conduction time along the early auditory pathways appeared to be related to the clinical picture; in fact, during periods of transitory clinical improvement these abnormalities were less evident. In addition, the encountered electrophysiological alterations consisted of a marked pathologic increase in the III-V interpeak latencies. The authors suggest that the BAEPs findings in their case could have been influenced by either unfavourable endogenous conditions (edema, electrolyte changes, etc.) or CNS segmental lesions due to focal viral distribution.
