Missing energies at pair creation

Wilson cloud chamber measurements of the separated spectra of positrons and electrons produced by gamma quanta of 6.14 MeV differ considerably from the theoretically predicted spectra by BETHE and HEITLER, but are in good agreement with those of a modified theory of pair creation

Gustoća i viskoznost poluvodičkog spoja AgGaSe2 u čvrstom i tekućem stanju

The density and kinematic viscosity of AgGaSe2 were investigated in the solid and liquid states in the temperature range 690 - 930 °C. Density and dynamic viscosity measurements were carried out using the thermometer method and the rotating cylinder method. Experimental data show that the dependence of viscosity on temperature has an activation character and that logarithm of viscosity vs. reciprocal absolute temperature can be approximated by two straight lines corresponding to activation energies 0.36 eV and 0.19 eV in the solid and liquid states, respectively. The temperature dependence of the free volume was calculated and it was found that it decreases linearly with temperature. The results are explained on the basis of the free-volume model.Istraživali smo gustoću i kinematičku viskoznost AgGaSe2 u čvrstom i tekućem stanju na temperaturama 690 – 930 ◦C. U mjerenjima gustoće i viskoznosti primijenili smo termometrijsku metodu odnosno metodu rotirajućeg valjka. Mjerni podaci ukazuju da ovisnost viskoznosti η o temperaturi ima aktivacijske značajke, te se ovisnost log η o temperaturi može aproksimirati pravcima koji odgovaraju aktivacijskim energijama 0.36 eV and 0.19 eV za čvrsto odnosno tekuće stanje. Izveli smo i temperaturnu ovisnost slobodnog volumena i našli da se linerno smanjuje s temperaturom. Ishodi mjerenja tumače se na osnovi modela slobodnog volumena

Gustoća i viskoznost poluvodičkog spoja AgGaSe2 u čvrstom i tekućem stanju

The density and kinematic viscosity of AgGaSe2 were investigated in the solid and liquid states in the temperature range 690 - 930 °C. Density and dynamic viscosity measurements were carried out using the thermometer method and the rotating cylinder method. Experimental data show that the dependence of viscosity on temperature has an activation character and that logarithm of viscosity vs. reciprocal absolute temperature can be approximated by two straight lines corresponding to activation energies 0.36 eV and 0.19 eV in the solid and liquid states, respectively. The temperature dependence of the free volume was calculated and it was found that it decreases linearly with temperature. The results are explained on the basis of the free-volume model.Istraživali smo gustoću i kinematičku viskoznost AgGaSe2 u čvrstom i tekućem stanju na temperaturama 690 – 930 ◦C. U mjerenjima gustoće i viskoznosti primijenili smo termometrijsku metodu odnosno metodu rotirajućeg valjka. Mjerni podaci ukazuju da ovisnost viskoznosti η o temperaturi ima aktivacijske značajke, te se ovisnost log η o temperaturi može aproksimirati pravcima koji odgovaraju aktivacijskim energijama 0.36 eV and 0.19 eV za čvrsto odnosno tekuće stanje. Izveli smo i temperaturnu ovisnost slobodnog volumena i našli da se linerno smanjuje s temperaturom. Ishodi mjerenja tumače se na osnovi modela slobodnog volumena

Seismic hazard studies in Egypt

Abstract The study of earthquake activity and seismic hazard assessment of Egypt is very important due to the great and rapid spreading of large investments in national projects, especially the nuclear power plant that will be held in the northern part of Egypt. Although Egypt is characterized by low seismicity, it has experienced occurring of damaging earthquake effect through its history. The seismotectonic sitting of Egypt suggests that large earthquakes are possible particularly along the Gulf of Aqaba–Dead Sea transform, the Subduction zone along the Hellenic and Cyprean Arcs, and the Northern Red Sea triple junction point. In addition some inland significant sources at Aswan, Dahshour, and Cairo-Suez District should be considered. The seismic hazard for Egypt is calculated utilizing a probabilistic approach (for a grid of 0.5° × 0.5°) within a logic-tree framework. Alternative seismogenic models and ground motion scaling relationships are selected to account for the epistemic uncertainty. Seismic hazard values on rock were calculated to create contour maps for four ground motion spectral periods and for different return periods. In addition, the uniform hazard spectra for rock sites for different 25 periods, and the probabilistic hazard curves for Cairo, and Alexandria cities are graphed. The peak ground acceleration (PGA) values were found close to the Gulf of Aqaba and it was about 220 gal for 475 year return period. While the lowest (PGA) values were detected in the western part of the western desert and it is less than 25 gal

Dielectric Function in Highly doped GaN Semiconductor

Inverse of Dielectric Function of highly doped  GaN has been calculated by using Lindhard formalism.  For simplicity collisional damping,  nonparabolicity and the coupling  between various  electrons and holes  were  neglected. The inverse of the dielectric function for both Fermi- Dirac and Maxwell Boltzman distribution showed antiscreening peak at small phonon wave vector. On the contrary, both Thomas Fermi and Debye inverse of dielectric function showed screening as expected at same phonon wave vector. There is a sharp growth in the antiscreening peak in the inverse of dielectric function at carrier temperature 77 K and 300K, accompanied with a singularity at carrier concentration greater than . Key words: dielectric function, GaN and screened optical phonon scattering rat

Establishment of two cell lines from embryonic cells of Pectinophora gossypiella (Lepidoptera : Gelichiidae)

Two cell lines from the most important insect pest of cotton, #Pectinophora gossypiella S., were obtained from an embryonic tissue culture. The cells were cultured in GRACE's modified medium. The first cell line, designated ORS-PgS (PgS), was obtained by selecting the non-adherent cells during subculturing and consisted of a homogeneous population of rounded cells. The second cell line, designated ORS-PgA (PgA), obtained without any artificial selection, was a heterogeneous population of spherical and spindle-shaped cells with a great capacity to adhere. The two cell lines had a doubling time of 40 and 48 h respectively and were sub-cultured for more than 50 passages. Their polypeptidic profiles appeared identical but were different from those of other lepidopteran cell lines tested. The two cell lines support the multiplication of #Autographa california nucleopolyhedrovirus, producing 100000 plaque forming units/ml. In 1 to 2% PgS cells, polyhedra were synthetized, whereas PgA cells multiplied only virions. (Résumé d'auteur

PHYTOCHEMICAL STUDY AND THE ANTIPROLIFERATIVE ACTIVITY OF INULA VULGARIS SPECIES GROWN IN LEBANON

Objective: Cancer represents the second leading cause of death after stroke and heart diseases. Plant extracts have long been used in traditional medicine for the prevention and treatment of many illnesses, including some types of cancer. The aim of this study was to evaluate the antiproliferative effects of ethyl acetate fractions of two Lebanese herbs: Inula viscosa (I. vis) and Inula vulgaris (I. vul).Methods: Plants were extracted with ethanol followed by ethyl acetate, then dried and tested on three cell lines including CaCO2, HepG2, and MCF7, to check for their viability and antiproliferative activity, using trypan blue exclusion and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assays. Proton (1H) and carbon (13C) nuclear magnetic resonance spectrometry (NMR) were used to identify the compounds that have been isolated from both Inula species.Results: The current findings were consistent for both trypan blue and MTT assays. The results showed that the most potent effect for I. vul was HepG2 (IC50 20 µg/ml, 27 µg/ml), and for I. vis on MCF7 (9 µg/ml, 15 µg/ml) and CaCO2 (12 µg/ml, 22 µg/ml) in the two mentioned assays respectively. However, insignificant differences were observed among the studied plants for each of the evaluated cells indicating comparable potencies. Quercetin, quercetin glycoside, and epicatechin derivatives were isolated by fractionation on column chromatography and identified using NMR spectroscopy.Conclusion: The antiproliferative activities of the two plants could be related to their content that is significant for high levels of secondary metabolites. The identification of those compounds is necessary to establish a relationship between their chemical structures and their activities

Cytotoxicity of Libyan Juniperus phoenicea against Human Cancer Cell Lines A549, EJ138, Hepg2 and MCF7

Background: The current study was undertaken to assess the cytotoxicity of the leaves of Libyan Juniperus phoenicea (Cupressaceae) against human cancer cell lines. Methods: The cytotoxicity of the n-hexane, dichloromethane (DCM) and methanol (MeOH) extracts of the leaves of J. phoenicea (JP), obtained from sequential Soxhlet extractions, was assessed against four human cancer cell lines: EJ138 (human bladder carcinoma), HepG2 (human liver hepatocellular carcinoma), A549 (human lung carcinoma) and MCF7 (human breast adenocarcinoma) using the MTT assay. Results: The cell line A549 was the most sensitive to the JP extracts, with the highest level of cytotoxicity with the IC50 values of 16, 13 and 100 μg/mL for the DCM, n-hexane and MeOH extracts, respectively. However, generally the most potent cytotoxic extract across the other cells tested was the n-hexane extract, followed by the DCM extract, whilst the MeOH extracts showed little or no cytotoxicity. The percentage of viability of cells decreased as the concentration of test compounds increased. The cytotoxicity of various chromatographic fractions from the extracts was also studied against the A459 cells. For the n-hexane fractions, the IC50 values were 160, 62, 90, 30, 9.5 and 40 μg/mL for fractions 1 to 5 and 7, respectively. Fractions 4 and 5 showed the greatest effect. DCM fractions 2, 3 and 4 had the IC50 values of 60, 92 and 19 μg/mL, respectively, and DCM fractions 5 to 8 were non-cytotoxic. Fractions 1 and 2 of the MeOH extract were non-cytotoxic, whereas cytotoxicity was observed for fractions 3 and 4 with IC50 values of 50 and 85 μg/mL, respectively. Conclusion: The outcome of the present study suggested that the JP leaves possess cytotoxic activities. The high level of cytotoxicity of the n-hexane and DCM extracts suggested that lipophilicity might affect the cytotoxicity of JP, where the less polar compounds had the strongest cytotoxicity

DIFFERENT TOPICAL FORMULATIONS OF KETOROLAC TROMETHAMINE FOR ANTI-INFLAMMATORY APPLICATION AND CLINICAL EFFICACY

Ketorolac tromethamine (KT) is considered as a member of NSAIDs that used in treatment of rheumatoid arthritis. The main problems associated with the frequent administration of KT orally could be overcome by alternative routes as topical application. KT was formulated in different topical formulations such as gels, emulgels and creams. Sodium carboxymethylcellulose, carbopol 934 and pluronic F127 were used as polymers. In vitro permeation study through rat skin was carried out. The effect of different KT concentrations and the effect of skin penetration enhancer on the amount of KT permeated were investigated. Anti-inflammatory activity using commercial piroxicam gel for comparison was evaluated. The effectiveness and tolerability of the selected KT gel and piroxicam gel in osteoarthritis patients was also studied. The results obtained showed that, the flux of the drug increased with increasing its initial concentration. Using sodium lauryl sulfate as enhancer resulted in an improvement of KT permeation through rat skin. All formulations had the potential for local applications of KT as anti-inflammatory drug as compared to the control group. There was no significant difference in the efficacy between the selected KT gel and piroxicam gel for osteoarthritis patients. So KT gel may be used as another therapeutic option for the treatment of patients with osteoarthritis