The geology and geochronology of Al Wahbah maar crater, Harrat Kishb, Saudi Arabia

Al Wahbah is a large (∼2.2 km diameter, ∼250 m deep) maar crater in the Harrat Kishb volcanic field in western Saudi Arabia. It cuts Proterozoic basement rocks and two Quaternary basanite lava flows, and is rimmed with an eroded tuff ring of debris from the phreatomagmatic explosion that generated the crater. A scoria cone on the northern wall of the crater was dissected by the explosion and exposes a dolerite plug that was intruded immediately prior to crater formation. The dolerite plug yields a <sup>40</sup>Ar/<sup>39</sup>Ar age of 1.147 ± 0.004 Ma. This is the best possible estimate of the time Al Wahbah crater formed. It is a few tens of thousand years younger than the age of the lower and upper basalt flows, 1.261 ± 0.021 Ma and 1.178 ± 0.007 Ma respectively. A dolerite dyke exposed within the basement in the wall of the crater is dated at 1.886 ± 0.008 Ma. This is the most precise age so far determined for the initiation of basaltic volcanism of Harrat Kishb, and confirms that it is significantly younger than the other post-rift volcanic provinces in the region. This study provides constrains the timing of humid climatic conditions in the region and suggests that the Quaternary basaltic volcanism that stretches the length of the western side of the Arabian peninsula may prove to be useful for establishing palaeoclimatic conditions

Concentrations of the Terrestrial Radionuclides and Their Radiological Risk at Wadi Nugrus, South Eastern Desert, Egypt

Fourteen samples were collected from a minor tributary at Wadi Nugrus, SED, Egypt. The average values of the activity concentrations of the terrestrial radionulclides U-238 and Th-232 in the studied samples were 325 and 277 (Bq/kg) much higher than the worldwide averages. The average value of K-40, 820 (Bq/kg), is comparable to the worldwide average concentration of this radionuclide. Four samples have safe values for the hazard indices Raeq, Hex and Hin. This represented a contradiction with values of the absorbed dose rate D which has a minimum value of 110 (nGy/h) exceeding the worldwide average of 60 (nGy/h). At the announced safe unity for both Hex and Hin, the total annual effective dose appears to have more than the value of 6 (mSv/y) which far exceeds the worldwide average effective dose rate of 1.5 (mSv/y). The effective dose approach established by UNSCEAR is reliable since the effective dose reacts directly with the dose limits recommended by the radiation protection regulations

Editorial: Molecular and multi-omic approaches in understanding cancer biology and anticancer therapies: current perspectives and new challenges

Peer Reviewe

Acute effects of cigarette smoking in habitual smokers, a focus on endothelial function

AbstractBackgroundThe chronic effect of cigarette (cig.) smoking is well established. The acute effect of smoking abolishes the concept, argued by heavy smokers, to decrease the number of smoked cigarettes instead of quitting.AimTo detect the acute effects of cigarette smoking and the duration of these effects.Patients and methodsThirty four smokers (age 21–35years) were studied at 3 occasions; 9h after the last cig. smoking, 5min after one cig. smoking and 30min after 3 cig. smoking within 30min. They were subjected to measurement of both ventricular functions using standard and tissue Doppler imaging (TDI), aortic distensibility, stiffness and endothelial function assessment by endothelium-dependent flow-mediated dilatation (FMD) and maximum vasodilatation.ResultsAfter one cigarette smoking, we found a statistically significant effect on blood pressure, Heart Rate, FMD percent, Dilation Ratio, aortic distensibility (P=0.007), and aortic stiffness index (ASI) (P=0.01). Furthermore the LV diastolic function was significantly impaired after smoking. Despite disappearance of acute effect of 3 cig. smoking within 30min on blood pressure, Heart Rate and aortic distensibility, a significant difference was still found as regards FMD percent and dilation ratio denoting the extension of the endothelial dysfunction for more than 30min after the last cigarette.ConclusionMany acute changes occur following one cigarette smoking even in habitual smokers. Persistence of endothelial dysfunction parameters after smoking indicates the failure of circulation adaptation in response to such offense that might contribute to the precipitation of acute events in vulnerable patients

Toxico-histological Effects of Sublethal Concentrations of Lead Nitrate on the Gills of the African Catfish, Clarias gariepinus

170-175This study aimed to investigate the effects of subleathal lead doses on the histological architecture of gills in the freshwater African catfish, Clarias gariepinus. Results revealed three stages of changes after exposure to three doses of lead nitrate. The changes were mild in fish exposed to 16.12 mg/L of Pb (NO3)2 (stage I 20% of LC50) and severe in case of 40% of LC50 (stage II, 32.24 mg/L) and 60% of LC50 (stage III 48.37% mg/L) in comparison to control. The histological examination revealed normal architecture of gills in control fish. Normal gills were characterized with primary gill lamellae with a central hyaline cartilage. However, three-stage changes were observed after exposure to the three doses of lead nitrate. In stage I, a cartilaginous matrix appeared along with loosening of the epithelial lining of the cartilaginous core and abundant vascular spaces were observed on the secondary gill lamellae. An extra cartilaginous matrix, loosening of the epithelial lining of the cartilaginous core, de-shaped gill lamellae, and degeneration of the secondary gill lamellae were noted in stage II. Lesions in the gill pattern in stage III were represented by shortening of the tips of secondary gill lamellae, damaged gill lamellae, a cartilaginous matrix, and hyperplasia. This indicated that lead exposure resulted in severe histopathological changes in the gills in a dose-dependent manner

Oral versus topical propranolol for management of superficial infantile hemangiomas: a comparative study

Background/purpose: Oral propranolol has been used successfully for the treatment of infantile hemangiomas (IHs). However, its safety is questioned. Topical therapy with 1% propranolol ointment has been reported to be safeand effective. The objective of this study was to compare the effectiveness and safety of oral versus topical propranolol (1% ointment) as a nonselective b-blocker in the management of cutaneous IH.Patients and methods: Forty-eight patients with IH were randomly divided into two equal groups: group A (n= 24) was treated with oral propranolol and group B (n= 24) was treated with propranolol ointment 1%. The patients were followed up for 3 months after treatment was stopped.Results: There was a significant statistical difference between the two groups as regards the effectiveness of the drug (P = 0.041). In the oral group, 50% (n= 12) showed an excellent response, 33.33% (n= 8) showed good response, and 16.67% (n =4) showed a fair response, whereas in the topical group 16.67% (n= 4) showed an excellent response, 45.83% (n= 11) showed good response, and 37.5% (n= 9) showed a fair response. There was no significant adverse event in any group during the follow-up period.Conclusion: Oral propranolol is an effective, safe, and fastacting drug for treating IH and can be monitored on an outpatient basis. Topical propranolol is an easily prepared drug and seems to be an alternative therapeutic option for superficial cutaneous hemangioma. However, the optimal dosing and duration of treatment are still to be defined. Keywords: infantile hemangiomas, propranolol, propranolol ointment, topical propranolo

Isogeometric analysis for functionally graded microplates based on modified couple stress theory

Analysis of static bending, free vibration and buckling behaviours of functionally graded microplates is investigated in this study. The main idea is to use the isogeometric analysis in associated with novel four-variable refined plate theory and quasi-3D theory. More importantly, the modified couple stress theory with only one material length scale parameter is employed to effectively capture the size-dependent effects within the microplates. Meanwhile, the quasi-3D theory which is constructed from a novel seventh-order shear deformation refined plate theory with four unknowns is able to consider both shear deformations and thickness stretching effect without requiring shear correction factors. The NURBS-based isogeometric analysis is integrated to exactly describe the geometry and approximately calculate the unknown fields with higher-order derivative and continuity requirements. The convergence and verification show the validity and efficiency of this proposed computational approach in comparison with those existing in the literature. It is further applied to study the static bending, free vibration and buckling responses of rectangular and circular functionally graded microplates with various types of boundary conditions. A number of investigations are also conducted to illustrate the effects of the material length scale, material index, and length-to-thickness ratios on the responses of the microplates.Comment: 57 pages, 14 figures, 18 table

Damage localization and quantification of composite stratified beam structures using residual force method

10.1088/1742-6596/842/1/012028Journal of Physics: Conference Series84211202