Nano BEA zeolite catalysts for the selective catalytic cracking of n-dodecane to light olefins.

Nano BEA zeolite catalysts were synthesized and modified by desilication and then ion-exchanged with Co. The desilication was carried out using 0.1 M of NaOH. The synthesized and modified nano BEA catalysts were characterized via different characterization techniques. Ammonia temperature program desorption (NH3-TPD) and the pyridine Fourier transform infrared (pyridine-FTIR) were utilized to investigate the acidity of catalysts. X-ray diffraction (XRD), 27Al and 29Si nuclear magnetic resonance (NMR) spectroscopy techniques were used to examine the structure of the catalysts. The XRD patterns of the as-synthesized nano BEA catalysts were identical to that of the reference, while the NMR analysis revealed the distribution of silicon and aluminum in the BEA structure. The scanning electron microscope (SEM) analysis confirmed that the fabricated catalysts were less than 100 nm. The desilication and Co ion-exchange altered the acidity of the catalyst. The catalysts were evaluated in the cracking of sssssss to light olefins in the temperature range from 400 °C to 600 °C. The conversion increased with the increase in the reaction temperature for both catalysts; the conversion was above 90% for the Co-BEA catalyst at a temperature above 450 °C. The yield of light olefins also increased at higher temperatures for both catalysts, while at a lower temperature the yield to light olefins was ca. 40% over that of Co-BEA.

Associations between ApoE gene and psychological consequences post stroke in a Bahraini cohort.

BACKGROUND: The contribution of genetic factors such as the presence of ApoE allele e4 and its association with psychological consequences post stroke remains unknown within Middle-Eastern regions. This study examined the association of ApoE genotype with cognitive impairment and mood in stroke patients and compare with healthy older adults in Bahrain. METHOD: A prospective sample of n = 62 stroke patients (case group) and n = 53 healthy ageing individuals (control group) were eligible to participate in the study. A neuropsychological battery of cognitive assessments were conducted on all participants, and then stratified by cognitive function: no cognitive impairment, mild cognitive impairment and moderate to severe cognitive impairment. Anxiety and depression were assessed using the Hospital Anxiety and Depression Scale (HADS). RESULTS: Most frequent ApoE genotype was e2/e3 in case (44%) and control groups (63%). ApoE allele e3 had the highest frequency for both groups with all stroke patients presenting with this allele and 86% for the control group (χ2 = 12.14, p < .0001). Stroke patients' non-carriers for ApoE allele e4 performed better on all cognitive measures but differences were not statistically significant (ns). Carriers of ApoE allele e2 in both groups had less mood symptoms compared to non-carriers. DISCUSSION: ApoE genotype e3/e4 and e4/e4 was low in this Bahraini cohort explaining why there may been no significant associations found for this genotype variant with cognitive impairment. Further investigation of cognitive impairment and mood dysregulation with the different variants of the ApoE gene in general ageing and stroke populations is required from different ethno-cultural groups and geographical regions globally.

Association Between Metacognition and Mood Symptoms Poststroke.

INTRODUCTION: The link between metacognition and mood has been well established, particularly in other conditions with psychological comorbidity, however, there is no evidence regarding this association in the area of stroke. AIM: The aim of this study was to examine the association between metacognition, based on the Self-Regulatory Executive Function model, and mood symptoms in the acute phase after stroke. METHODS: One hundred thirty patients were recruited to a prospective stroke study in Bahrain, and n = 64 were assessed for mood and cognition. A neuropsychological battery of cognitive assessments included the following measures: the Mini-Mental State Examination, the Trail Making Test (A+B), and the Metacognition Questionnaire 30 (MCQ-30) for metacognition. The Hospital Anxiety and Depression Scale assessed mood symptoms, and stroke severity was measured using the National Institute of Health Stroke Severity Scale. RESULTS: Total MCQ-30 scores were significantly associated with both anxiety (r = .47, P = .001) and depression (r = .54, P <. 0001). The MCQ-30 subscales' cognitive confidence, cognitive self-consciousness, and uncontrollability/danger were the specific factors to be associated with mood symptoms (P < .01). Global cognition (r =.32, P < .01), but not executive function, was significantly associated with depression only. Metacognition remained a statistically significant correlate with depression (ß = .42, P < .0001) and anxiety (ß = .51, P < .0001) after adjusting for education and global cognition. DISCUSSION: Metacognition is a better determinant of mood symptoms after stroke, especially in regions where illiteracy levels are high in older populations, in comparison to executive function and global cognition.

Dystonia associated with atlantoaxial subluxation.

A case of primary dystonia with atlantoaxial subluxation is reported. This 46-year-old man who was suffering from primary generalized dystonia since childhood presented with clinical features suggestive of recent onset of cervical myelopathy. Imaging studies confirmed presence of severe spondylotic changes in the cervical spine with cord compression along with atlantoaxial subluxation. It is important to identify this potentially dangerous complication, which may be surgically managed. This is the first case report in the literature about the association of atlantoaxial subluxation and primary dystonia.

Profile of stroke in Bahrain.

OBJECTIVE: As no report on the pattern of stroke in Bahrain is available, we sought to determine the stroke types, the annual incidence rate, and the risk factors associated with different types of stroke in Bahrain nationals and expatriates in Bahrain. METHODS: Case records of patients admitted with stroke from January 1995 to December 1995 in a tertiary level hospital, the only one with a well established neurology service in Bahrain were reviewed. Diagnosis of stroke and its type were confirmed by clinical and computerized tomography of brain. Risk factor analysis was made based on clinical, laboratory and other relevant investigational data. RESULTS: The majority of strokes occurred in middle and late age Bahrainis. Males predominated in all types of strokes, except in the hemorrhagic type, among the Bahrainis. The crude annual incidence rate was 57 per 100,000 Bahrainis. The frequency of stroke types in Bahrainis was cerebral infarction in 53%, cerebral hemorrhage in 30% and unspecified in 16.5%; as against 76%, 10% and 15% in non Bahrainis. Subarachnoid hemorrhage was rare (2%). Hypertension, dyslipidemia, diabetes mellitus and ischemic heart disease and smoking were common risk factors for ischemic and hemorrhagic strokes. CONCLUSION: Stroke incidence in Bahraini nationals is similar to that in developing countries and from other parts of the Arabian Peninsula. The differences observed in age and gender distribution and in the stroke types between Bahraini nationals and non Bahraini expatriates is most likely a reflection of the demographic structure existing in Bahrain.

Profile of stroke in Bahrain.

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Multiple mitochondrial DNA deletions associated with autosomal recessive ophthalmoplegia and severe cardiomyopathy.

Six patients in two unrelated families from the eastern Arabian peninsula presented with childhood-onset progressive external ophthalmoplegia (PEO), mild facial and proximal limb weakness, and severe cardiomyopathy requiring cardiac transplantation. Muscle biopsies showed ragged-red and cytochrome c oxidase-negative fibers. The activities of several complexes in the electron-transport chain were decreased and Southern blot analysis showed multiple mtDNA deletions. The apparent autosomal-recessive inheritance and the association with cardiomyopathy distinguish this syndrome from autosomal-dominant PEO with multiple mtDNA deletions. The combination of autosomal-recessive PEO, cardiomyopathy, and multiple mtDNA deletions appears to be another disease due to a defect of communication between the nuclear and mitochondrial genomes.