Enhancement in photocatalytic water splitting using van der Waals heterostructure materials based on penta-layers.

Recently, van der Waals heterostructures (vdWHs) have been used to improve the performance of 2D materials, enabling more applications. By using first-principles calculations, we have studied the electronic and optical properties of vdWHs composed of penta-siligraphene and other penta-layers (p-Si2C4/p-X; X = Si2N4, ZnO2, Ge2C4 or SiGeC4). The stability of the vdWHs is verified by computing their binding energy, vibrational phonon spectra and ab initio molecular dynamics simulations. By assessing the electronic properties, we have found that the p-Si2C4/p-ZnO2, p-Si2C4/p-Ge2C4 and p-Si2C4/p-SiGeC4 vdWHs are semiconductors with an indirect band gap characterized by type-I band alignment. Meanwhile, the p-Si2C4/p-Si2N4 vdWH is a quasi-direct band gap semiconductor characterized by type-II band alignment. Bader charge analysis and charge density of p-Si2C4/p-Si2N4 vdWHs showed that photogenerated electrons move from the p-Si2N4 monolayer to the p-Si2C4 monolayer limiting the recombination of photogenerated charges and improving the photocatalytic efficiency. Furthermore, the p-Si2C4/p-Si2N4 vdWH exhibits suitable band edge positions compared to isolated monolayers suggesting its potential applicability in photocatalytic water splitting. The calculated optical absorption revealed that the p-Si2N4 monolayer exhibits substantial optical absorption in the ultraviolet (UV) range, while the p-Si2C4 monolayer and the p-Si2C4/p-Si2N4 vdWH show outstanding optical absorption on the order of 105 cm-1 in the visible and UV ranges. More importantly, the p-Si2C4/p-Si2N4 vdWH can greatly improve the optical absorption in these regions, which leads to high-efficiency usage of solar energy. Our study provides a route to design new vdWHs based on pentagonal monolayers, as well as an efficient photocatalyst for photocatalytic water splitting and optical devices.

Neuropsychiatric symptoms, seizure severity, employment, and quality of life of Jordanians with epilepsy.

RATIONALE: Depression and anxiety are more strongly associated with quality of life (QOL) than seizure frequency in several populations with epilepsy. However, QOL is culturally determined and may be influenced by cultural values and norms as well as local policies and resources. The goal of this study is to investigate the impact of neuropsychiatric symptoms and seizure severity on QOL and employment in people with epilepsy living in Jordan. METHODS: Seizure severity and complications, antiepileptic drug side effects, social stigma, neuropsychiatric symptoms, and mental health (MH-SF36) and physical health (PH-SF36) domains of QOL were assessed in 45 adult patients with epilepsy in a university neurology clinic. Multivariate regression analysis was used to evaluate the relationship between these variables and the quality of life of Jordanians with epilepsy. RESULTS: Neuropsychiatric symptoms, seizure frequency, and history of injury due to seizure were associated with the MH-SF36. However, earlier age of seizure onset, longer duration of epilepsy, unemployment, and history of chronic disease was associated with lower PH-SF36 scores. Furthermore, there were no differences in QOL, neuropsychiatric symptoms, and seizure frequency in Jordanians who were employed versus unemployed in this study. CONCLUSIONS: Neuropsychiatric symptoms were significantly associated with mental health-related QOL measures, but not with physically-related QOL measures, in Jordanians with epilepsy. For studies across populations, it is critical to separate mental health from physical health QOL measures. Furthermore, regional differences in culture and policy may more strongly influence employment status than individuals' experiences of epilepsy, neuropsychiatric symptoms, or QOL in some populations.

Ischaemic stroke in Jordan: a 2-year hospital-based study of subtypes and risk factors.

A retrospective study was made of 200 consecutive patients with first-ever ischaemic stroke, admitted to Jordan University Hospital over a 2-year period. The mean age was 61.2 years (range 29-95). The most common stroke subtype was lacunar infarct (51.5%), but frequency of cardioembolic stroke was low (8.0%). Hypertension, diabetes mellitus and smoking were the most common risk factors for atherosclerotic non-cardioembolic stroke. Chronic atrial fibrillation was the most common risk factor for cardioembolic stroke. No patient had severe extracranial carotid or vertebral artery stenosis (> 50% narrowing). Lacunar strokes presented predominantly as pure motor stroke (67/103) and were mainly in the internal capsule (34/ 103). The favourable outcome (85% discharged home) may be due to the relatively young age and the predominance of lacunar infarcts.

Ischaemic stroke in Jordan: a 2-year hospital-based study of subtypes and risk factors

A retrospective study was made of 200 consecutive patients with first-ever ischaemic stroke, admitted to Jordan University Hospital over a 2-year period. The mean age was 61.2 years [range 29-95]. The most common stroke subtype was lacunar infarct [51.5%], but frequency of cardioembolic stroke was low [8.0%]. Hypertension, diabetes mellitus and smoking were the most common risk factors for atherosclerotic non-cardioembolic stroke. Chronic atrial fibrillation was the most common risk factor for cardioembolic stroke. No patient had severe extracranial carotid or vertebral artery stenosis [> 50% narrowing]. Lacunar strokes presented predominantly as pure motor stroke [67/103] and were mainly in the internal capsule [34/ 103]. The favourable outcome [85% discharged home] may be due to the relatively young age and the predominance of lacunar infarcts

Guillain-Barre syndrome: a series observed at Riyadh Armed Forces Hospital January 1984--January 1994.

A consecutive series of 47 hospitalized cases of Guillain-Barre syndrome seen over a 10-year period was analysed with respect to: (1) age and sex; (2) antecedent events and seasonal distribution; (3) patterns of clinical presentation; (4) CSF and neurophysiological findings; (5) results of treatment with plasma exchange; and (6) outcome. Twenty-two were children, 20 middle-aged and 5 aged; 37 were male and 10 were female. The most frequent antecedent event was upper respiratory tract infections; a seasonal peak incidence was found in winter. Clinical, CSF and neurophysiological findings concurred with those in the Western literature; 79% of the cases were severe. Plasma exchange performed within the first 2 weeks of onset benefitted in the short-term outcome, i.e. improvement by 1 grade at 4 weeks, but the long-term benefit, i.e. the ability to regain independent locomotion, was questionable. Plasma exchange helped in curtailing the time to walking unaided but had no benefit on the duration of artificial ventilation. Factors associated with an adverse outcome were: age over 15 years, severity of motor electrodiagnostic findings (especially a decreased distal CMAP amplitude and EMG signs of acute denervation), requirement for ventilation and slow progression (>3 weeks) to maximum deficit. After a mean follow-up of 11 months, 55% of the patients regained independent locomotion, which is a comparatively low proportion.

The effect of nimodipine on essential tremor.

We investigated the effect of nimodipine (30 mg qid) in 16 de novo patients with essential tremor in a double-blind placebo-controlled study in which we assessed tremor by clinical scorings, tremorgraphic recordings, and patient self-evaluation. Of the 15 patients who completed the study, eight improved. We conclude that nimodipine is effective in some patients with essential tremor.

Long-term therapy of essential tremor with flunarizine.

We investigated the effect of long-term treatment of essential tremor (ET) with flunarizine (Fz) (10 mg/day) in 17 subjects who had a favorable response to 1 month of treatment. Side effects (dystonia, parkinsonism, weight gain and depression) occurred in 29.4% (5/17) of patients, leading to drug discontinuation. Fz was still effective at the end of 30 months of treatment in 41% (7/17) of patients. Loss of efficacy was observed in 29.4% (5/17) of patients. It is concluded that Fz is an alternative for long-term treatment of patients with ET; however, loss of efficacy and side effects are common.

Posttraumatic paroxysmal nocturnal hemidystonia.

The term "nocturnal paroxysmal dystonia" has been used to describe patients who display paroxysmal episodes of dystonic-dyskinetic movements arising during nonrapid eye movement sleep, in particular stages 2-3 (Lugaresi E, Cirignotta F. Hypnogenic paroxysmal dystonia: epileptic seizure or a new syndrome. Sleep 1981;4: 129-138). The pathogenesis of these attacks has remained controversial. We describe a patient with posttraumatic paroxysmal nocturnal hemidystonia. Acetazolamide led to improvement.

A new neurocutaneous syndrome possibly related to Ota's nevus.

The case of a 42-year-old Sudanese man is reported who had developed hyperpigmentation of the left face and rapidly progressive right hemiparesis followed by myoclonus at the age of 30. Blue-grey hyperpigmentation was noted in the territory of the left ophthalmic, maxillary and mandibular trigeminal nerve branches, with alopecia of the right face and axilla. CT of the brain revealed left-sided paraventricular calcifications and MRI showed atrophy of the left cerebral hemisphere and mesencephalon, a calcified haemangioma in the left basal ganglia, an old infarct in the right central pons, and cerebellar atrophy. This case resembles Ota's syndrome; however, atypical distribution of the facial nevus, the epidermal location of hyperpigmentation, and the combination of vascular and degenerative cerebral malformations indicate that this is a new hitherto unreported neurocutaneous vascular syndrome.

Flunarizine in migraine: a double-blind placebo-controlled study (in a Saudi population).

We evaluated the effect of flunarizine (Fz) (10 mg/d) on migraine in a double-blind placebo-controlled design. The attacks' frequency, duration, severity and associated symptoms were compared before and after treatment. Forty-two patients completed a three-month trial period; 21 patients received Fz and 21 placebo. Statistical analysis showed no significant difference between Fz and placebo (p > 0.05). In this study Fz was not more efficient than placebo in migraine.