Isothermal annealing study of the EH1 and EH3 levels in n-type 4H-SiC.

Particle irradiation is known to give rise to several majority carrier traps in the band gap of n-type 4H-SiC, in the 0.4-1.6 eV energy range below the conduction band edge (E C). Among these traps, the EH1 (E C-0.4 eV) and the EH3 (E C-0.7 eV) are the least thermally stable ones and not much is known on their microscopic origin. In order to understand the nature of EH1 and EH3, their annealing kinetics was studied by means of deep level transient spectroscopy and the results were interpreted by invoking the diffusion-limited theory. It is found that EH1 and EH3 are two different charge states of the same defect, labeled EH-center, that anneals out with an activation energy of ∼1.1 eV and whose nature is related to a carbon interstitial. Our study shows that the EH-center is not the same as the S-center defect which was reported by previous studies found in the literature.

Natalizumab treatment in multiple sclerosis patients: a multicenter experience in clinical practice in Italy.

We evaluated efficacy of natalizumab in relapsing-remitting multiple sclerosis patients in a clinical practice setting. We report data on the first consecutive 343 patients receiving natalizumab in 12 multiple sclerosis (MS) Italian centers enrolled between April 2007 and November 2010. The main efficacy endpoints were the proportion of patients free from relapses, disease progression, combined clinical activity, defined as presence of relapse or disease progression, from MRI activity, and from any disease activity defined as the absence of any single or combined activity. At the end of follow-up, the cumulative proportion of patients free from relapses was 68%; the proportion of patients free from Expanded Disability Status Scale (EDSS) progression was 93%; the proportion of patients free from combined clinical activity was 65%; the proportion of patients free from MRI activity was 77%; and the proportion of patients free from any disease activity was 53%. Natalizumab was effective in reducing clinical and neuroradiological disease activity. Its effectiveness in clinical practice is higher than that reported in pivotal trials and was maintained over time.

Ab initio study of isolated chlorine defects in cubic SiC.

The electronic properties and formation energy of isolated Cl defects in SiC were investigated by first-principles calculations. Chlorine was studied in a substitutional position, in either a carbon (Cl(C)) or a silicon site (Cl(Si)), and in two interstitial positions (Cl(i)), either tetrahedral or octahedral configurations. Our calculations revealed that Cl(C) is energetically favored and it is a likely candidate to explain the nature of the experimentally observed Cl incorporation reported in SiC epilayers grown by chloride-based chemical vapor deposition.

The effects of displacement threshold irradiation energy on deep levels in p-type 6H-SiC.

We report on the electrical characterization, by means of deep level transient spectroscopy, of electron-irradiated Al-doped 6H-SiC epilayers. Samples were irradiated with either 116 keV, in order to displace only carbon atoms, or 400 keV. Seven deep traps, in the 0.1-1.6 eV range above the valence band, were found. The thermal stability of the detected levels was analyzed by performing an isochronal annealing series in the 100-1800 °C temperature range and the atomic structure of most of the detected traps was found to be related to C-displacement.

The structural and electronic properties of chiral SiC nanotubes: a hybrid density functional study.

Hybrid density functional theory was employed in investigating the structural and electronic properties of 14 chiral and 3 armchair SiC nanotubes (SiCNTs). The role of the tube diameter, as well as that of the chiral angle theta, was studied in detail by considering nanotubes of diameters varying from 2 to 9 A and chiral angles theta varying between 7 degrees and 30 degrees. The study revealed that all the investigated SiCNTs are semiconductors with a broad spectrum of bandgap values ranging from 0.2 to 2.9 eV and that the structural stability of the nanotubes increases with diameter. By analyzing the behavior of the molecular orbitals, an explanation of the mechanism by which theta affects the determination of such values is put forward.

Conversion of recent onset atrial fibrillation with single loading oral dose of propafenone: is in-hospital admission absolutely necessary?

A population of 283 patients with recent onset (< 72 hours) AF, without heart failure, who received a single 450- or 600-mg oral dose of propafenone, or digoxin 1 mg, or placebo for conversion to sinus rhythm (SR), was studied to determine whether a routine admission to the hospital for drug administration is justified. Previous bradyarrhythmias or sick sinus syndrome (SSS), and concomitant use of antiarrhythmic drugs were exclusion criteria. None of the 283 patients studied experienced VT or VF and none of them needed implantation of a temporary pacemaker. Periods of atrial tachyarrhythmias with regularization of atrial waves and 1:1 AV conduction were observed in only two cases, both receiving placebo. No predictor of proarrhythmia was found among the clinical variables considered (age, etiology, arrhythmia duration, atrial dimension, and blood potassium). No serious hemodynamic adverse effects were noted in either group. The rates of conversion to SR after 4 hours were: 80 (57%) of 141 patients who received propafenone and 35 (25%) of 142 patients who received digoxin or placebo (P < 0.001). Acute oral treatment with propafenone is simple and effective for the conversion of recent onset AF to SR in patients without clinical signs of heart failure. The routine admission of these patients to the hospital is not necessary. Home-based administration of oral propafenone to a selected group of patients could significantly increase the cost effectiveness of this treatment.

Immunohistochemical analysis of c-Fos and c-Jun in retinoblastoma.

The c-fos promoter is negatively regulated by the retinoblastoma (Rb)-susceptibility-gene-encoded protein as well as by other genes involved in the control of transcription, cell cycle regulation and neoplastic transformation. We have examined by immunohistochemistry the c-Fos and c-Jun proteins in five cases of retinoblastoma in order to evaluate eventual alterations in their expression in vivo, possibly related to a gene mutation or to loss of Rb negative control.

The eyes in imagery and perceptual processes: first remarks.

Through an echographic system we examined the activity of the crystalline lens of 10 men and women during real perceptual activity and during imagery. Subjects had to perceive near and far stimuli and to imagine reading a word on a page of a book (near imagined stimulus) or seeing a ship on the horizon (far imagined stimulus). Results showed that processes of accommodation (linked to the variations of the optical axis of the crystalline lens) occur in both real and imaginative conditions. The first results suggest an active role of the eye during imagery.

Fibronectin, cholesterol and triglycerides ascitic fluid concentration in the prediction of malignancy.

There have been few trials comparing the efficacy of determinations of cholesterol, fibronectin and triglycerides for diagnosis of malignant ascites. In this study we measured these in 200 ascitic fluids from 93 cirrhotic patients (Group A), 47 hepatocellular-carcinoma patients (Group B), 60 extra-hepatic tumour patients (Group C), 44 of them with malignant cells (Group Cpos) and 16 without (Group Cneg). Anova one-way and the Bonferroni test for multiple comparisons showed that fibronectin and cholesterol were significantly higher in the ascitic fluids of patients of group C than of groups A and B (mean +/- ESM) (Cholesterol in A: 27.2 +/- 2.8; in B 23.5 +/- 1.5; in C: 68.6 +/- 5.3 mg/dl. Fibronectin in A: 32.7 +/- 2.8; in B 31.3 +/- 2.6; in C 127.7 +/- 11.1 mg/l). Both were significantly higher in Group Cpos than in Group Cneg (Cholesterol in Cneg: 41.2 +/- 6.7; in Cpos: 78.6 +/- 6.2 mg/dl. Fibronectin in Cneg: 55.0 +/- 11.2; in Cpos 154 +/- 12.3 mg/dl). We found no differences between cirrhotic ascites and malignant ascites due to primary liver hepatocellular-carcinoma. No difference at all in triglycerides were detected. With the Receiver-Operating Characteristic (ROC) curve, cholesterol had the best Youden Index (57%) at a cut-off of 32 mg/dl (sensitivity 78.3%, specificity 79.3% at this level); the best Youden Index (64%) for fibronectin had a cut-off of 60 mg/dl (sensitivity 65%, specificity 89.3%). Triglycerides appeared to be a great deal less effective as a diagnostic marker, with their best Youden Index (23%) at a cut-off 32 mg/dl (sensitivity 66.7%, specificity 56.4%).(ABSTRACT TRUNCATED AT 250 WORDS)

Tissue polypeptide antigen (TPA) in urinary bladder cancer cytology: a follow-up study.

Tissue polypeptide antigen (TPA) has been detected by immunocytochemical assay on urine cytological samples from 28 asymptomatic patients, who previously had a histological diagnosis of papillary transitional cell carcinoma (PTCT) of the urinary bladder (UB), in order to evaluate its role in follow-up controls. TPA staining intensity (SI) in urothelial cells was evaluated to improve the diagnostic accuracy of cytology. Differentiated tumor cells were strongly stained for TPA, heavier than normal urothelial cells. Undifferentiated neoplastic cells were less stained for TPA with a wide range of SI. TPA detection revealed positive cytology in 21 (75%) of the considered cases. The accuracy of our cytological findings compared with both routine examinations and subsequent histopathological diagnosis was of 95.2%. Follow-up urinary cytology limits could be reduced by TPA searching in differentiated tumor cells, deriving from low-grade neoplasms.

Use of botulinum toxin in Meige's disease.

Four patients with severe Meige's disease (blepharospasm-oromandibular dystonia) have been treated, after having given an informed consent, by local injections of purified botulinum toxin type "A". Previous systemic therapy with anticholinergics, dopamine antagonists and other drugs had been unsuccessful in all these subjects. Each patient was treated by saline solution injected with the same method as botulinum toxin, just once. The self-evaluation of patients and the clinical evaluation that some of us- unaware of the kind of therapy which had been performed- gave to the symptoms on the basis of videotapes, for each session of injection, showed that the injections of botulinum toxin are effective in the treatment of such disorder. The duration of the beneficial effect was slightly shorter in these patients than in patients with blepharospasm treated by the same method.

Beneficial effect of botulinum A toxin in blepharospasm: 16 months' experience with 16 cases.

After introducing the problem of blepharospasm, we report our experience on treatment with purified botulinum A toxin in 16 cases of blepharospasm, symptomatic in two and essential in 14, than had not responded to drugs. The changes in intensity and frequency of spasm after treatment were evaluated on a clinical scale and by review of videotapes. The beneficial effect appeared within a week in most patients, lasting from 6 to 28 weeks (mean 13), and reached the maximum at the third-seventh week. Mild spasms and female patients responded better. Repeated injections were followed by better response to the drug. Complications, exclusively local, were represented by transient corneal exposure, ptosis, lacrimation or diplopia.

The anterior segment anomalies in the Warburg syndrome. A study of new cases.

The Warburg syndrome is a primary lethal neurodysplasia recently defined with autosomal recessive inheritance. The clinical diagnosis is based on the association of brain alterations with ocular defects, among which the anterior segment anomalies and the retinal dysplasia appear to be the most significant. The authors report a clinical and histopathological study on personal observations.

Unusual association of Eales disease with multifocal neurological deficit.

A man who had suffered from Eales disease at the age of 20 presented an acute Brown-Séquard spinal syndrome when he was 30, followed shortly after by paralysis of the right abducens and recurrent laryngeal nerves. Steroid treatment apparently relieved the myelopathy while the neurological deficits have remained unchanged for the past 14 years. In view of the clinical and CSF findings the neurological deficits are attributed to the same disease process as that underlying the peripheral retinal abnormalities characteristic of Eales disease rather than to multiple sclerosis.

Pharmacokinetics of cimetidine in patients with unresponsive duodenal ulcer.

The pharmacokinetics of cimetidine after an oral dose of 400 mg were measured in 18 patients with duodenal ulcer, 9 refractory and 9 responders. The peak plasma concentration of cimetidine (2.13 +/- 0.17 micrograms/ml vs 1.43 +/- 0.04 micrograms/ml), the area under the plasma concentration curve (A.U.C.) between 0 to 8 hours after cimetidine (8.49 +/- 0.29 micrograms/ml/h vs 5.83 +/- 0.25 micrograms/ml/h), and the time span in which cimetidine was above 0.5 micrograms/ml (I.C.50) (401 +/- 8.86 min vs 296 +/- 20 min) were all found to be greater in responding patients than in non-responders to the therapy. No differences were detectable between the two groups in urinary excretion, T 1/2 of cimetidine or percentage inhibition (1%) of maximal pentagastrin-stimulated acid output (MAO). The results indicate that clinical healing of duodenal ulcer after cimetidine is related principally to the drug's pharmacokinetics, i.e. to its absorption from the small bowel, and that some other therapeutic approaches might be tried before surgery in cases of duodenal ulcer refractory to cimetidine.

Family studies and HLA typing in ankylosing spondylitis and sacroiliitis.

The families of 21 ankylosing spondylitis (AS) and 16 sacroiliitis (SI) patients were investigated and typed for HLA markers. The association of HLA B27 with AS was confirmed, but no strong evidence for the same or other HLA markers being associated with SI was found. Inheritance patterns in families were analyzed according to the multifactorial and monofactorial models. It is proposed that a major gene associated or interacting with the B27 product controls the susceptibility to AS, and that this gene behaves as a dominant with incomplete penetrance. The problem as to whether linkage disequilibrium maintained by selective pressure, or functional epistasis between the "disease gene" and the B27 antigen may be the acting mechanism of association, remains to be elucidated.