Radiation resistance of elastomeric O-rings in mixed neutron and gamma fields: Testing methodology and experimental results.

Materials and components employed in the presence of intense neutron and gamma fields are expected to absorb high dose levels that may induce deep modifications of their physical and mechanical properties, possibly causing loss of their function. A protocol for irradiating elastomeric materials in reactor mixed neutron and gamma fields and for testing the evolution of their main mechanical and physical properties with absorbed dose has been developed. Four elastomeric compounds used for vacuum O-rings, one fluoroelastomer polymer (FPM) based and three ethylene propylene diene monomer rubber (EPDM) based, presently available on the market have been selected for the test. One EPDM is rated as radiation resistant in gamma fields, while the other elastomers are general purpose products. Particular care has been devoted to dosimetry calculations, since absorbed dose in neutron fields, unlike pure gamma fields, is strongly dependent on the material composition and, in particular, on the hydrogen content. The products have been tested up to about 2 MGy absorbed dose. The FPM based elastomer, in spite of its lower dose absorption in fast neutron fields, features the largest variations of properties, with a dramatic increase in stiffness and brittleness. Out of the three EPDM based compounds, one shows large and rapid changes in the main mechanical properties, whereas the other two feature more stable behaviors. The performance of the EPDM rated as radiation resistant in pure gamma fields does not appear significantly better than that of the standard product. The predictive capability of the accelerated irradiation tests performed as well as the applicable concepts of threshold of radiation damage is discussed in view of the use of the examined products in the selective production of exotic species facility, now under construction at the Legnaro National Laboratories of the Italian Istituto Nazionale di Fisica Nucleare. It results that a careful account of dose rate effects and oxygen penetration in the material, both during test irradiations and in operating conditions, is needed to obtain reliable predictions.

[The evaluation of aphasic deficits for the definition of a targetted logotherapeutic treatment]. / Valutazione dei deficit afasici per la definizione di un trattamento logoterapico mirato.

The Aachener Aphasie Test (AAT) is the major German test for the diagnosis of aphasic disorders. The test is easy to use and is valid and reliable for the diagnosis of aphasia and its severity and to evaluate the recovery of the aphasic disorder after language rehabilitation. The AAT is, however, not sufficient to define cognitively sound logotherapeutic treatment. The use of tasks which are based on cognitive functional models allows the identification of specific processing levels that have been damaged by a cerebral lesion, and the definition of a focussed rehabilitation plan. In this paper, we will discuss the results of a cognitive neurolinguistic treatment in a patient who suffered of Broca's aphasia with agrammatism and phonological dyslexia.

Motor rehabilitation: evolution of functional markers in trained hemiparetic patients and effectiveness of synchronous techniques.

The authors investigated, by means of isokinetic tests, a group of normotonic hemiparetic patients with the aim of showing the evolution, and in the short and medium term, functional markers of muscle strength and motor patterns. The results showed that the efficacy of the synchronous techniques used was good during the period of use. In the medium term, while the recovery of strength remained constant, the motor patterns deteriorated as co-contraction of antagonistic muscle groups restarted. This did not, however, lead to functional regression in comparison with the short term result (effectiveness).

Effects of intravenous high dose co-dergocrine mesylate ('Hydergine') in elderly patients with severe multi-infarct dementia: a double-blind, placebo-controlled trial.

A double-blind, placebo-controlled trial was carried out in 40 patients affected by multi-infarct dementia to see if a daily intravenous infusion of 3 mg co-dergocrine mesylate ('Hydergine') over 14 days would improve severely deteriorated elderly patients and shorten the latent period (3 months) which is observed when the drug is given orally. All the patients had severe mental impairment, psychological deficit or altered consciousness. A Hachinski score of 7 or more, and a cumulative score of at least 12 points on SCAG scale Items 1, 2 and 4 (anxiety/depression) and/or Items 5, 6 and 8 (alertness/confusion) were required for admission. After 1 week of intravenous infusion of placebo, patients were randomly allocated to treatment with co-dergocrine mesylate or placebo, from Day 1 to Day 14. The solutions were infused over a period of 2 hours. During the follow-up period from Day 15 to Day 21, the patients did not receive any treatment. Thirty-six patients (17 on co-dergocrine mesylate, 19 on placebo) completed the study. The results, as rated on the SCAG scale, indicated significant improvements, in favour of co-dergocrine mesylate, in cognitive dysfunction, mood depression, withdrawal and overall impression. Furthermore, the factor fatigue on the Nowlis scale and clinical global assessments by physicians also showed significant advantages of the co-dergocrine mesylate group over placebo. Nine out of 17 co-dergocrine mesylate patients complained of side-effects, usually experienced during infusion; they consisted mainly of nausea (6 patients), gastric discomfort (2 patients), and tremor, nasal congestion, flushing, hypotension and hypertension (1 patient each). Despite the appearance of side-effects, general tolerability was rated as 'good' by both physicians and patients. It is concluded, therefore, that intravenous high dose co-dergocrine mesylate treatment has a fast and clinically relevant effect on the key clinical symptoms of multi-infarct dementia.

[Visual feedback on the maximal momentum of the voluntary tibio-tarsal dorsal flexion in hemiplegic patients]. / Studio di un feedback visivo sul momento massimo volontario di flessione dorsale della tibio-tarsica in pazienti emiplegici.

In both sides (healthy and plegic) of an hemiplegic group the evaluation of tibio-tarsic isometric torque (with and without the aid of a visual feed-back) was carried out. No significative differences in the "total biological work" during a series of ten contractions, in the two cases were found. A marked increase of the pin-point single contraction in the hemiplegic side was noted. A smoothing in the decrement of the total biological work during serial contractions was also found.

[Electroanalgesia by transcutaneous stimulation (TNS). Response to the naloxone test]. / Elettroanalgesia da stimolazione transcutanea (TNS). Risposta al test al naloxone.

The authors, after a review of the literature about TNS, suggest the comparison between three different TNS techniques from two points of view: A) Pain relief estimate; B) Response to Naloxone Test. To this purpose a impulse generator delivered a biphasic square-wave stimulus with duration of 0.40 msec and amplitude (peak to peak) to 130 mVolt, was used. TNS techniques used are so characterized 1) Frequency 80 Hz; Duration 30'; 2) Frequency 80 Hz; Duration over 120'; 3) Frequency 2/4 Hz; Duration over 120'. Although the techniques used for Group (1) provided the best numerical result in the evaluation of the pain relief, endorphine activity cannot be maintained owing to Naloxone Test negativity. Pain relief of (2) and (3) Group was statistically significant although not numerically at the same level of (1) Group. In the laters, on the contrary, positivity of Naloxone Test seems to hint at the activation of endorphine. This fact suggest to the authors hypothesis in the purpose to spot TNS site of action.

[Sensitive electrodiagnostic examination in patients with chronic pain treated with transcutaneous stimulation electroanalgesia]. / L'esame elettrodiagnostico sensitivo in pazienti affetti da dolore cronico trattati con elettroanalgesia di stimolazione transcutanea.

The electrodiagnostic sensitive exam on patients suffering from a chronic pain treated which transcutaneous electroanalgesia stimulation. G. Ital Med Lav 1983; 5: 89 - 94. The AA carry out this exam before, during and after the sittings of electroanalgesia. The only parameter to vary in such research is the sensitive Reobase, which raises during the T.E.N.S. lasting unchanged for the all active period, turning then to the basal values within the following fifteen minutes at the end of application. As no other significant changes occur bath the frequency change of stimulus and the total period of application have no influence. What said above and the unchanged period of analgesic level after the return to the values of the sensitive Reobase when the T.E.N.S. is interrupted let us assume that such mechanism is of unspecific type and not involved in the mechanism of control of pain from the T.E.N.S. itself.

A control study of muscle force recovery in hemiparetic patients during treatment with functional electrical stimulation.

A group of forty-nine hemiparetic patients with limited emotional, communication and sensibility involvement and with recent lesion of cerebrovascular aetiology was randomly divided into two groups of twenty-four and twenty-five subjects. Both groups received traditional physiotherapy treatment for one hour/day, one group received twenty min/day of peroneal nerve stimulation. The maximum voluntary dorsal flexion moments of the ankle joint of the affected and non affected extremities were measured with an isometric brace twice a week for one month and for both groups. The recovery of moment in the stimulated group turned out to be about three times greater than in the control group and considerably less dependent upon age, time from lesion, initial value, side of lesion. Three patients using a peroneal brace at home as an assisting device were again evaluated two months later and a further improvement was observed. This work gives statistical support to previous observations based on very few cases and provides a statistically reliable answer concerning the entity of FES induced recovery of muscle force in hemiparetic subjects.