Photo-electrical properties of 2D quantum confined metal-organic chalcogenide nanocrystal films

Hybrid quantum wells are electronic structures where charge carriers are confined along stacked inorganic planes, separated by insulating organic moieties. 2D quantum-confined hybrid materials are of great interest from a solid-state physics standpoint because of the rich many-body phenomena they host, their tunability and easy synthesis, allowing the creation of material libraries. In addition, from a technological point of view, 2D hybrids are promising candidates for efficient, tunable, low-cost materials impacting a broad range of optoelectronic devices. Different approaches and materials have, therefore, been investigated, with the notable example of 2D metal halide hybrid perovskites. Despite the remarkable properties of such materials, the presence of toxic elements like lead is not desirable in applications and their ionic lattices may represent a limiting factor for stability under operating conditions. Therefore, non-ionic 2D materials made with non-toxic elements are preferable. In order to expand the library of possible hybrid quantum well materials, herein, we consider an alternative platform based on non-toxic, self-assembled, metal-organic chalcogenides. While the optical properties have been recently explored and some unique excitonic characters highlighted, photo-generation of carriers and their transport in these lamellar inorganic/organic nanostructures and critical optoelectronic aspects remain totally unexplored. We hereby report the first investigation on the electrical properties of the air-stable [AgSePh]_∞ 2D coordination polymer in the form of nanocrystal (NC) films readily synthesized in situ and at low temperature, compatible with flexible plastic substrates. The wavelength-dependent photo-response of the NC films suggests the possible use of this material as a near-UV photodetector. We therefore built a lateral photo-detector, achieving a sensitivity of 0.8 A W^-1 at 370 nm, thanks to a photoconduction mechanism, and a cut-off frequency of ∼400 Hz, and validated its reliability as an air-stable UV detector on flexible substrates.

Levetiracetam versus carbamazepine in patients with late poststroke seizures: a multicenter prospective randomized open-label study (EpIC Project)

BACKGROUND

Strokes are the leading cause of epileptic seizures in adults and account for 50% of seizures in those over the age of 65 years. The use of antiepileptic drugs to prevent recurrent poststroke seizures is recommended.

METHODS

One hundred and twenty-eight patients with poststroke seizures were randomly allocated to treatment with either levetiracetam (LEV) or sustained-release carbamazepine (CBZ) in a multicenter randomized open-label study. After a titration study phase (2 weeks), the optimal individual dose of trial medication was determined and treatment was continued for another 52 weeks. The primary endpoint was defined as the proportion of seizure-free patients; the secondary endpoints were: evaluation of time recurrence to the first seizure, EEG tracings, cognitive functions and side effects.

RESULTS

Of 128 patients, 22 discontinued the trial prematurely; thus a total of 106 patients (52 treated with LEV and 54 treated with CBZ) were included in the analysis. The results of the study were as follows: no significant difference in number of seizure-free patients between LEV and CBZ (p = 0.08); time to the first recurrence tended to be longer among patients on LEV; there was no correlation between the therapeutic effect and the EEG findings in either treatment group; LEV caused significantly fewer (p = 0.02) side effects than CBZ; attention deficit, frontal executive functions and functional scales (Activities of Daily Living and Instrumental Activities of Daily Living indices) were significantly worse in the CBZ group.

CONCLUSIONS

This trial suggests that LEV may be a valid alternative to CBZ in poststroke seizures, particularly in terms of efficacy and safety. In addition, our results show that LEV has significant advantages over CBZ on cognitive functions. This trial also indicates that LEV in monotherapy is a safe and effective therapeutic option in elderly patients who have suffered epileptic seizures following a stroke.

Stiff person syndrome and motor mononeuropathy with conduction block: a singular association

The "Stiff person syndrome"(SPS) is a rare dysimmune chronic neurological disorder, sometimes paraneoplastic, characterized by progressive stiffness, painful persistent or spasmodic muscle contractions, mostly involving spine and lower extremities. In 60 to 90 percent of cases, non-paraneoplastic forms are associated to the presence of anti-glutamic acid decarboxylase (anti-GAD) antibodies in the cerebrospinal fluid and in the serum, while anti-amphiphysin antibodies are frequently associated to paraneoplastic types. The relevant treatment consists of three basic approaches: increase in the inhibitory processes in charge of muscle activity control, re-modulation of the immune response, removal of any associated neoplasia. Indications regarding the efficacy of high-dose intravenous immunoglobulin (IVIG) also in this dysimmune pathology are on the increase. We described an unusual case of autoimmune SPS associated with an exclusively motor left peroneal nerve neuropathy, with conduction block, treated with high-dose intravenous immunoglobulin (IVIG), oral cyclosporine, sodium valproate, baclofen and diazepam.

Cerebellar subacute syndrome due to corticosteroid-responsive encephalopathy associated with autoimmune thyroiditis (also called "Hashimoto's encephalopathy")

The corticosteroid-responsive encephalopathy associated with autoimmune thyroiditis (the so-called "Hashimoto's Encephalopathy") is a rare disorder with multiple symptomatology, breaking out with an acute or subacute onset and having a relapsing course, not correlated to thyroid hormone levels, with autoimmune pathogenesis, and usually associated with Hashimoto's thyroiditis. In this paper, we report on a case study regarding a 46 year-old woman showing a subacute course cerebellar syndrome, associated with Hashimoto's thyroiditis, diagnosed as "Hashimoto's encephalopathy". The possible pathogenesis and the major aspects of the differential diagnostic sector are discussed with particular reference to an ataxic syndrome caused by a progressive non-familial adult onset cerebellar degeneration (PNACD), associated with the thyroid disease itself.

Neurocysticercosis treated with albendazole long term follow-up of a case

The authors report a case of neurocysticercosis treated with Albendazole (methyl-5-propyl-thio-2-benzimidazilcarbamate). Computerized tomography (CT) and magnetic resonance imaging (MRI) of the brain presented various small bilateral parenchymal calcifications in the white matter and two inflammatory granulomatous formations localized respectively in the left and right posterior parietal lobe. After the serological diagnosis (Elisa-test) of cysticercosis, the patient was treated with albendazole (Zentel) with oral doses of 15 mg/kg/die for 20 days, and successively with a lower dose for another 40 days. Repeated CT and MRI showed a gradual reduction in the granulomas in comparison with the ones previously found, until the complete disappearance of the neuroradiological evidence of them. No side-effects were recorded during the treatment nor symptoms or neurological consequences in the period up until two years after the initial observation.