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 (EC). Among these traps, the EH1 (EC-0.4 eV) and the EH3 (EC-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.

Red wine activates plasma membrane redox system in human erythrocytes

In the present study, we report that polyphenols present in red wine obtained by a controlled microvinification process are able to protect human erythrocytes from oxidative stress and to activate Plasma Membrane Redox System (PMRS). Human plasma obtained from healthy subjects was incubated in the presence of whole red wine at a concentration corresponding to 9.13-73 μg/ml gallic acid equivalents to verify the capacity to protect against hypochlorous acid (HOCl)-induced plasma oxidation and to minimize chloramine formation. Red wine reduced hemolysis and chloramine formation induced by HOCl of 40 and 35%, respectively. PMRS present on human erythrocytes transfers electrons from intracellular molecules to extracellular electron acceptors. We demonstrated that whole red wine activated PMRS activity in human erythrocytes isolated from donors in a dose-dependent manner with a maximum at about 70-100 μg/ml gallic acid equivalents. We also showed that red wine increased glutathione (GSH) levels and erythrocytic antioxidant capacity, measured by 2,2-diphenyl-1-picrylhydrazyl (DPPH) quenching assay. Furthermore, we reported that GSH played a crucial role in regulating PMRS activity in erythrocytes. In fact, the effect of iodoacetamide, an alkylating agent that induces depletion of intracellular GSH, was completely counteracted by red wine. Bioactive compounds present in red wine, such as gallic acid, resveratrol, catechin, and quercetin were unable to activate PMRS when tested at the concentrations normally present in aged red wines. On the contrary, the increase of PMRS activity was associated with the anthocyanin fraction, suggesting the capacity of this class of compounds to positively modulate PMRS enzymatic activity.

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.