Direct conversion of natural gas into COx-free hydrogen and MWCNTs over commercial Ni–Mo/Al2O3 catalyst: Effect of reaction parameters

A commercial hydrotreating nickel molybdate/alumina catalyst was used for the direct conversion of natural gas (NG) into COx-free hydrogen and a co-valuable product of multi-walled carbon nanotubes (MWCNTs). The catalytic runs were carried out atmospherically in a fixed-bed flow reactor. The effect of reaction temperature between 600 and 800 °C, and dilution of the NG feed with nitrogen as well as pretreatment of the catalyst with hydrogen were investigated. At a reaction temperature of 700 °C and dilution ratio of NG/N2 = 20/30, the optimum yield of H2 (∼80%) was obtained with higher longevity. However, using the feed ratio of NG/N2 = 30/20, the optimum yield of MWCNTs was obtained (669%). X-ray diffraction pattern for the catalyst after the reaction showed that the MWCNTs were grown on the catalyst at all reaction temperatures under study. TEM pictures revealed that the as-grown MWCNTs at 600, 650 and 800 °C are short and long with a low graphitization degree. At 700 °C a forest of condensed CNTs is formed, whereas both carbon nanofibers and CNTs were formed at 750 °C

Synthesis and Anticonvulsant Activity of Certain N-Aralkyl-N-(1-Substituted Cyclohexyl) Benzenamines

The synthesis of certain N-aralkyl(1-aminomethylcyclohexyl) benzenamines 6a-i, N-(alkyloxymethyl or aralkyloxymethylcyclohexyl)-N-arylbenzenamines 9a-l and 1-(1-(aralkylphenylamino)cyclohexyl methoxy)-3-isopropylaminopropan-2-ols 11a-c has been accomplished. These compounds exhibited anticonvulsant activity. Compounds 9h, 9b and 11a at doses 0.06, 0.075 and 0.08 mmol/kg, respectively provoked maximal anticonvulsant potential against pentylenetetrazol (PTZ) induced seizures test compared with diphenylhydantoin (0.2 mmol/kg) and valproic acid (0.24mmol/kg)

The Concordance between Myocardial Perfusion Imaging and Coronary Angiography in Detecting Coronary Artery Disease: A Retrospective Study in a Tertiary Cardiac Center at King Abdullah Medical City

Background. Coronary artery disease (CAD) is considered as the leading cause of the cardiovascular fatalities worldwide. CAD is diagnosed by many modalities of imaging such as myocardial perfusion imaging (MPI) and coronary angiography (CAG). Methods. A retrospective cross-sectional study was conducted that included all patients referred to the KAMC (King Abdullah Medical City) nuclear cardiology lab from its opening until the end of May 2014 (a period of 17 months). A total of 228 patient reports with a history of conducting either CAG or MPI or both were used in this study and statistically analyzed. Results. An analysis of the MPI results revealed that 78.5% of the samples were abnormal. On the other hand, 26.75% of the samples revealed that they were subjected to CAG and MPI. There was a significant and fair agreement between MPI and CAG by using all the agreement coefficients (kappa = 0.237, phi = 0.310, and value = 0.043). The sensitivity, specificity, and accuracy of MPI with reference to CAG were 97.8%, 20%, and 78.69%, respectively. In addition, positive predictive and negative predictive values were 78.95% and 75%, respectively. Conclusion. In a tertiary referral center, there was a significant agreement between MPI and CAG and a high accuracy of MPI. MPI was a noninvasive diagnostic test that could be used as a gatekeeper for CAG

Anticonvulsant Profiles of Certain New 6-Aryl-9-substituted-6,9-diazaspiro-[4.5]decane-8,10-diones and 1-Aryl-4-substituted-1,4-diazaspiro[5.5]undecane-3,5-diones

Synthesis and anticonvulsant potential of certain new 6-aryl-9-substituted-6,9-diazaspiro[4.5]decane-8,10-diones (6a–l) and 1-aryl-4-substituted-1,4-diazaspiro[5.5] undecane-3,5-diones (6m–x) are reported. The intermediates 1-[(aryl)(cyanomethyl)amino] cycloalkanecarboxamides (3a–f) were prepared via adopting Strecker synthesis on the proper cycloalkanone followed by partial hydrolysis of the obtained nitrile functionality and subsequent N-cyanomethylation. Compounds 3a–f were subjected to complete nitrile hydrolysis to give the respective carboxylic acid derivatives 4a–f which were cyclized under mild conditions to give the spiro compounds 5a–f. Ultimately, compounds 5a–f were alkylated or aralkylated to give the target compounds 6a–i and 6m–u. On the other hand, compounds 6j–l and 6v–x were synthesized from the intermediates 5a–f through alkylation, dehydration and finally tetrazole ring formation. Anticonvulsant screening of the target compounds 6a–x revealed that compound 6g showed an ED50 of 0.0043 mmol/kg in the scPTZ screen, being about 14 and 214 fold more potent than the reference drugs, Phenobarbital (ED50 = 0.06 mmol/kg) and Ethosuximide (ED50 = 0.92 mmol/kg), respectively. Compound 6e exhibited an ED50 of 0.019 mmol/kg, being about 1.8 fold more potent than that of the reference drug, Diphenylhydantoin (ED50 = 0.034 mmol/kg) in the MES screen. Interestingly, all the test compounds 6a–x did not show any minimal motor impairment at the maximum administered dose in the neurotoxicity screen