Usage of Carbon Isotopes in Characterizing Groundwater Age, Flow Direction, Flow Velocity and Recharge Area

AbstractCarbon-13 and Carbon-14 isotopes were utilized in this study to determine the age, flow direction, flow velocity and recharge area of groundwater in the two main aquifers of Kuwait. For this purpose 20 groundwater samples were collected from the Kuwait group aquifer and lower Dammam formation aquifer. The collected groundwater samples were analyzed for 14C activity and 13C activity. 14C activity was measured using accelerator mass spectrometry (AMS) and expressed as percentage modern carbon (pmc) while 13C was measured using an isotope ratio mass spectrometer (IRMS) and expressed as permil (‰) in the form of CO2 gas. The interpretation of the analysis results of carbon isotopes data indicated that the general groundwater flow direction is towards north east and the estimated groundwater velocities are 11 to 30 m/a for Kuwait group aquifer and 12 to 21 m/a for Dammam formation aquifer. Based on the estimated groundwater velocities, the approximate location of the recharge areas of these aquifers was identified. The groundwater ages calculated for Kuwait group aquifer varied from 800 a B.P for modern ground water in the northern part to 22500 a B.P for very old groundwater in the northeastern part, while the age of Dammam formation groundwater is 26000 to 36000 a B.P

Flexible modified plastic strips coated polyaniline/graphene composite for electrochemical biosensors

616-624Polyaniline(PANI)/graphene modified flexible, disposable polyester overhead projector (OHP) strips for non-enzymatic detection of ascorbic acid (AA) and uric acid (UA) is demonstrated in the current work. The deposition of PANI on the 3-aminopropyltrimethoxy silane (APTMS) modified OHP have been optimized through electrochemical impedance spectroscopy. Graphene is coated on another end. The PANI/graphene coating is confirmed through scanning electron microscopy. UA and AA detection have been carried out using the standard electrochemical techniques like cyclic voltammetry and chronoamperometry. The study reveals that the composite of PANI/graphene exhibits good sensing towards the detection of UA and AA. During the detection of UA and AA, PANI/graphene has showed enhanced current density with quick response and a linear concentration range of 10 to 300 μM for UA and 30 to 80 μM for AA. These flexible sensor strips may be of great potential in real-time UA and AA detection

Iron porphyrin molecules on Cu(001): Influence of adlayers and ligands on the magnetic properties

The structural and magnetic properties of Fe octaethylporphyrin (OEP) molecules on Cu(001) have been investigated by means of density functional theory (DFT) methods and X-ray absorption spectroscopy. The molecules have been adsorbed on the bare metal surface and on an oxygen-covered surface, which shows a $\sqrt{2}\times2\sqrt{2}R45^{\circ}$ reconstruction. In order to allow for a direct comparison between magnetic moments obtained from sum-rule analysis and DFT we calculate the dipolar term $7$, which is also important in view of the magnetic anisotropy of the molecule. The measured X-ray magnetic circular dichroism shows a strong dependence on the photon incidence angle, which we could relate to a huge value of $7$, e.g. on Cu(001) $7$ amounts to -2.07\,\mbo{} for normal incidence leading to a reduction of the effective spin moment $m_s + 7$. Calculations have also been performed to study the influence of possible ligands such as Cl and O atoms on the magnetic properties of the molecule and the interaction between molecule and surface, because the experimental spectra display a clear dependence on the ligand, which is used to stabilize the molecule in the gas phase. Both types of ligands weaken the hybridization between surface and porphyrin molecule and change the magnetic spin state of the molecule, but the changes in the X-ray absorption are clearly related to residual Cl ligands.Comment: 17 figures, full articl

Field-regulated switching of the magnetization of Co-porphyrin on graphene

Differentmagnetic couplingmechanisms have been identified for a fewmonolayers of Co-porphyrin molecules deposited on a graphene-covered Ni(111) single crystal. A relatively strong antiferromagnetic coupling of the first molecular layer via graphene to the Ni crystal in comparison to a weaker intermolecular coupling gives rise to a complex field-dependent response of this hybrid system. By continuously increasing the magnetic field strength, the net magnetization of the molecular system switches from antiparallel to parallel to the field direction at 2.5 T. Utilizing x-ray absorption spectroscopy and x-ray magnetic circular dichroism, the element-specific magnetization and field dependence was probed. The nature of the magnetic couplings is identified by means of density functional theory and orbital-dependent susceptibilities

Causes of large-scale landslides in the Lesser Himalaya of central Nepal

Abstract: Geologically and tectonically active Himalayan Range is characterized by highly elevate

Larvicidal activities of 2-Aryl-2,3-Dihydroquinazolin -4-ones against malaria vector Anopheles arabiensis, In Silico ADMET prediction and molecular target investigation

Malaria, affecting all continents, remains one of the life-threatening diseases introduced by parasites that are transmitted to humans through the bites of infected Anopheles mosquitoes. Although insecticides are currently used to reduce malaria transmission, their safety concern for living systems, as well as the environment, is a growing problem. Therefore, the discovery of novel, less toxic, and environmentally safe molecules to effectively combat the control of these vectors is in high demand. In order to identify new potential larvicidal agents, a series of 2-aryl-1,2-dihydroquinazolin-4-one derivatives were synthesized and evaluated for their larvicidal activity against Anopheles arabiensis. The in silico absorption, distribution, metabolism, excretion, and toxicity (ADMET) properties of the compounds were also investigated and most of the derivatives possessed a favorable ADMET profile. Computational modeling studies of the title compounds demonstrated a favorable binding interaction against the acetylcholinesterase enzyme molecular target. Thus, 2-aryl-1,2-dihydroquinazolin-4-ones were identified as a novel class of Anopheles arabiensis insecticides which can be used as lead molecules for the further development of more potent and safer larvicidal agents for treating malaria.Fil: Venugopala, K. N.. Durban University Of Technology; SudáfricaFil: Pushpalatha, R.. Reva University; IndiaFil: Tratat, C.. King Faisal University; Arabia SauditaFil: Gleiser, Raquel M.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Córdoba. Instituto Multidisciplinar de Biología Vegetal (P). Grupo Vinculado Centro de Relevamiento y Evaluación de Recursos Agrícolas y Naturales; ArgentinaFil: Bhandary, S.. Indian Institute Of Science Education And Research Bhopal; IndiaFil: Chopra, D.. Indian Institute Of Science Education And Research Bhopal; IndiaFil: Morsy, M.. King Faisal University; Arabia SauditaFil: Al-Dhubiab, B. E.. King Faisal University; Arabia SauditaFil: Attimarad, M. B.. King Faisal University; Arabia SauditaFil: Nair, A.. King Faisal University; Arabia SauditaFil: Sreeharsha, N.. King Faisal University; Arabia SauditaFil: Venugopala, R.. University Of Kwazulu-natal; SudáfricaFil: Deb, P. K.. Philadelphia University; JordaniaFil: Chandrashekharappa, S.. Institute For Stem Cell Biology And Regenerative Medicine; IndiaFil: Khalil, H.. King Faisal University; Arabia SauditaFil: Alwassil, O.. King Saud Bin Abdulaziz University For Health Sciences; Arabia SauditaFil: Abed, S. N.. Philadelphia University; JordaniaFil: Bataineh, Y. A.. Philadelphia University; JordaniaFil: Palenge, R.. Reva University; IndiaFil: Haroun, M.. King Faisal University; Arabia SauditaFil: Pottathil, S.. King Faisal University; Arabia SauditaFil: Girish, M. B.. Reva University; IndiaFil: Akrawi, S. H.. King Faisal University; Arabia SauditaFil: Mohanlall, V.. Durban University Of Technology; Sudáfric

Activation of SK2 channels preserves ER Ca(2+) homeostasis and protects against ER stress-induced cell death

Alteration of endoplasmic reticulum (ER) Ca(2+) homeostasis leads to excessive cytosolic Ca(2+) accumulation and delayed neuronal cell death in acute and chronic neurodegenerative disorders. While our recent studies established a protective role for SK channels against excessive intracellular Ca(2+) accumulation, their functional role in the ER has not been elucidated yet. We show here that SK2 channels are present in ER membranes of neuronal HT-22 cells, and that positive pharmacological modulation of SK2 channels with CyPPA protects against cell death induced by the ER stressors brefeldin A and tunicamycin. Calcium imaging of HT-22 neurons revealed that elevated cytosolic Ca(2+) levels and decreased ER Ca(2+) load during sustained ER stress could be largely prevented by SK2 channel activation. Interestingly, SK2 channel activation reduced the amount of the unfolded protein response transcription factor ATF4, but further enhanced the induction of CHOP. Using siRNA approaches we confirmed a detrimental role for ATF4 in ER stress, whereas CHOP regulation was dispensable for both, brefeldin A toxicity and CyPPA-mediated protection. Cell death induced by blocking Ca(2+) influx into the ER with the SERCA inhibitor thapsigargin was not prevented by CyPPA. Blocking the K(+) efflux via K(+)/H(+) exchangers with quinine inhibited CyPPA-mediated neuroprotection, suggesting an essential role of proton uptake and K(+) release in the SK channel-mediated neuroprotection. Our data demonstrate that ER SK2 channel activation preserves ER Ca(2+) uptake and retention which determines cell survival in conditions where sustained ER stress contributes to progressive neuronal death.Cell Death and Differentiation advance online publication, 20 November 2015; doi:10.1038/cdd.2015.146.</p