Phosphoric acid and pH sensors based on polyaniline films

M.M. Ayad,N.A. Salahuddin,M.O. Alghaysh,R.M. Issa 한국물리학회 2010 Current Applied Physics Vol.10 No.1

Polyaniline (PANI)-chemically coated the electrode of quartz-crystal microbalance (QCM) has been developed for the determination of phosphoric acid (H3PO4) in the liquid phase. The sensing mechanism is based on the fact that the QCM devices produce a change in the oscillating frequency when the PANI coating the electrode of QCM interacts with different concentration of the acid. This was made during the subsequent redoping.dedoping processes of the PANI film in acid and ammonia solutions, respectively. Also,this was made during the successive redoping in different acid solutions. The QCM sensor demonstrated a rapid response to the acid with an excellent reversibility. A linear response of the sensor for different concentrations of H3PO4 was found in region of ≤1 M. The conductivity at different concentration of the acid was also determined. Finally, pH dependence on the electronic absorption of PANI phosphate film was studied which indicates that the film can be used as a sensor over a wider pH range of 3.12. This is in comparison to a PANI-sulphate film which shows limited pH absorption dependence (5.8).

A novel method for improving the microstructure and electrical properties of Pr6O11-based ZnO varistors

Qaid Salem A. S.,Issa M. A. A.,Hassib A. M.,Al-Asbahi Bandar Ali,Abuassaj E. M.,Ahmed Abdullah Ahmed Ali 한국세라믹학회 2022 한국세라믹학회지 Vol.59 No.6

The eff ects of diff erent synthesis routes and sintering temperatures on the microstructures and electrical properties of ceramic varistors (composed of ZnO doped with Pr 6O11, Co 3O4, Cr 2O3, and Nd 2O3) were investigated. Two types of samples were prepared according to the milling approach (single-mill or double-mill). Remilling the calcined powder material reduced the required sintering temperature by 100 °C, improved the microstructure of the ceramic, and enhanced the nonlinear properties of the varistor. Though the diff erent sintering temperatures and average grain sizes, both types were reach ≈ 98% of the theoretical density. The highest nonlinear coeffi cient value was ≈ 26.5, obtained from the fi rst sample of the double- mill batch. As the sintering temperature increased, the nonlinearity diminished rapidly in the case of single-mill samples compared to double-mill ones. Similar behavior was noted for the varistor (breakdown) voltage. The thermionic emission behavior at the pre-breakdown region and the conduction mechanism through Schottky barriers were applied to fi nd further electrical parameters.

An Investigation of the Awareness and Use of Open Access Initiative at the Federal Polytechnic, Offa, Kwara State, Nigeria

Issa, A.O.,Igwe, K.N.,Akangbe, B.R.,Aliyu, M.B. Korea Institute of Science and Technology Informat 2014 Journal of Information Science Theory and Practice Vol.2 No.3

This study investigated the information environment of lecturers in Federal Polytechnic, Offa, Kwara State, Nigeria, in relation to their information seeking behavior, extent of use of the polytechnic library, perceptions of the resources and services of the library, level of awareness and extent of use of the open access model of scholarly communications, as well as the challenges of accessing and using information resources. It adopted the survey research method, using a questionnaire for data collection, while the descriptive statistics method was used to analyse the data, using tabular presentation and simple percentages. From a population of 280 lecturers for the study, a purposive sample of 164 was drawn. The findings showed that the lecturers' information needs are focused on online use; they hardly use the polytechnic library due to their perceptions of the resources and services of the library. They are, to a greater extent, aware of open access initiatives, but do not publish in open access outlets, while various challenges affect their access and use of information resources for teaching and research. A recommendation was made, among others, that the polytechnic management should pay more critical attention to the library especially in the areas of adequate, current and comprehensive collections on all the programmes of the institution, as well as the provision of wireless internet services on the campus through a public-private partnership arrangement.

Studies on the Anti-Inflammatory and Analgesic Effects ofExtracts from Marine Sponges

Issa M.I. Fakhr,Nehal A. Hamdy,Mohamed A.A. Radwan,Seham A. El-Batran,Osama A. El Shabrawy 한국생약학회 2006 Natural Product Sciences Vol.12 No.2

specimens of sponges collected from Red Sea, Egypt, were investigated f or their contents ofsecondary metabolites. The crude extracts of the sponges were tested for their anti-inflammatory and analgesiceffects. The toxic effects of the extracts of the two marine sponges were studied. LD50 determination revealed thatthe investigated extracts of ‘Igernella and Ircinia spp’ were 4.69 and 134.7mg/100g b.wt., respectively, whentwo marine sponges extracts showed significant anti-inflamatory and analgesic eff ects. Keywordsanti-inflammatory, analgesic, sponges, Igernella, Ircinia

A rapid and direct method for half value layer calculations for nuclear safety studies using MCNPX Monte Carlo code

Tekin H.O.,ALMisned Ghada,Issa Shams A.M.,Zakaly Hesham M.H. 한국원자력학회 2022 Nuclear Engineering and Technology Vol.54 No.9

Half Value Layer calculations theoretically need prior specification of linear attenuation calculations, since the HVL value is derived by dividing ln(2) by the linear attenuation coefficient. The purpose of this study was to establish a direct computational model for determining HVL, a vital parameter in nuclear radiation safety studies and shielding material design. Accordingly, a typical gamma-ray transmission setup has been modeled using MCNPX (version 2.4.0) general-purpose Monte Carlo code. The MCNPX code's INPUT file was designed with two detection locations for primary and secondary gamma-rays, as well as attenuator material between those detectors. Next, Half Value Layer values of some well-known gamma-ray shielding materials such as lead and ordinary concrete have been calculated throughout a broad gamma-ray energy range. The outcomes were then compared to data from the National Institute of Standards and Technology. The Half Value Layer values obtained from MCNPX were reported to be highly compatible with the HVL values obtained from the NIST standard database. Our results indicate that the developed INPUT file may be utilized for direct computations of Half Value Layer values for nuclear safety assessments as well as medical radiation applications. In conclusion, advanced simulation methods such as the Monte Carlo code are very powerful and useful instruments that should be considered for daily radiation safety measures. The modeled MCNPX input file will be provided to the scientific community upon reasonable request.

Enhancement of nuclear radiation shielding and mechanical properties of YBiBO₃ glasses using La₂O₃

Issa, Shams A.M.,Ali, Atif Mossad,Tekin, H.O.,Saddeek, Y.B.,Al-Hajry, Ali,Algarni, Hamed,Susoy, G. Korean Nuclear Society 2020 Nuclear Engineering and Technology Vol.52 No.6

In this study, nuclear radiation shielding and rigidity parameters of Y (0.1-x)B0.6Bi1.8O3La2x glassy system were investigated in order to determine it's suitability for use as nuclear radiation shielding materials. Therefore, a group of bismuth borate glass samples with La₂O₃ additive were synthesized using the technique of melt quenching. According to the results, the increase of the La₂O₃ additive increases the density of the glass samples and the mass attenuation coefficient (μ_m) values, whereas the half-value layer (HVL) and mean free path (MFP) values decrease. The effective atomic number (Z_eff) is also enhanced with an increment of both mass removal cross section for neutron (Σ_R) and absorption neutron scattering cross section (σ_abs). In addition to the other parameters, rigidity parameter values were theoretically examined. The increase of La₂O₃ causes some other important magnitudes to increase. These are the average crosslink density, the number of bonds per unit volume, as well as the stretching force constant values of these glass samples. These results are in concordance with the increase of elastic moduli in terms of the Makishima-Mackenzie model. This model showed an increase in the rigidity of the glass samples as a function of La₂O₃.

Physical and nuclear shielding properties of newly synthesized magnesium oxide and zinc oxide nanoparticles

Rashad, M.,Tekin, H.O.,Zakaly, Hesham MH.,Pyshkina, Mariia,Issa, Shams A.M.,Susoy, G. Korean Nuclear Society 2020 Nuclear Engineering and Technology Vol.52 No.9

Magnesium oxide (MgO) and Zinc oxide (ZnO) nanoparticles (NPs) have been successfully synthesized by solid-solid reaction method. The structural properties of ZnO and MgO NPs were studied using X-ray diffraction (XRD) and scanning electron microscopy (SEM). XRD results indicated a formation of pure MgO and ZnO NPs. The mean diameter values of the agglomerated particles were around to be 70 and 50 nm for MgO and ZnO NPs, respectively using SEM analysis. Further, a wide-range of nuclear radiation shielding investigation for gamma-ray and fast neutrons have been studied for Magnesium oxide (MgO) and Zinc oxide (ZnO) samples. FLUKA and Microshield codes have been employed for the determination of mass attenuation coefficients (μ_m) and transmission factors (TF) of Magnesium oxide (MgO) and Zinc oxide (ZnO) samples. The calculated values for mass attenuation coefficients (μ_m) were utilized to determine other vital shielding properties against gamma-ray radiation. Moreover, the results showed that Zinc oxide (ZnO) nanoparticles with the lowest diameter value as 50 nm had a satisfactory capacity in nuclear radiation shielding.

Effect of cypermethrin on the postnatal development of the medulla oblongata and the possible protective role of melatonin in albino rats

Marwa A. Al-Gholam,Noha M. Issa 대한해부학회 2020 Anatomy & Cell Biology Vol.53 No.4

Previous studies have shown that cypermethrin (CYP), a broad spectrum pesticide has a teratogenic effect on rat offspring born to an exposed dam with no information on its effect on the development of the brain. To the best of our knowledge, this research is the first attempt to study the postnatal development medulla oblongata of rat offspring exposed to CYP during the perinatal period and the possible neuroprotective role of melatonin. The offspring of treated female rats were organized into control, melatonin (1 mg/kg/day orally); CYP (12 mg/kg/day orally); and CYP/melatonin groups. The mothers received treatments from day 6 of gestation until day 21 after birth. At Postnatal days 7 and 21, the animals were sacrificed and their medulla oblongata was removed and subjected to histological, immunohistochemical, and electron microscopic studies. CYP induced neuronal degeneration by chromatolysis and pyknosis. Nuclear changes, cytoplasmic vacuolation, damage mitochondria, and breakdown of RER were also detected. Reduction of microtubule-associated protein-2 (MAP-2), myelin basic protein (MBP), and oligodendrocyte transcription factor expressions and increment of glial fibrillary acidic protein expression in the medulla oblongata of the developing rats were observed. On the other hand, melatonin led to an obvious improvement of the injured medulla oblongata tissues and ameliorating the damaging effects of CYP. In conclusion, melatonin has protected rats against CYP-induced histopathological and immunohistochemical changes. This may be due to the protection of MAP-2, conservation of MBP, an increment of oligodendrocytes, and alleviation of astrogliosis.

The eccentricity extended energy of a graph

Mohammad Issa Sowaity,B. Sharada,A. M. Naji 장전수학회 2019 Proceedings of the Jangjeon mathematical society Vol.22 No.2

Let ei be the eccentricity of the vertex vi of a graph G, where ei = maxfd(u; v) : u 2 V (G)g. In this paper, we introduce the eccentricity extended matrix Aeex(G), so that its (i,j)-entry is equal to 1 2 ( ei ej + ej ei ) for vivj 2 E and 0 otherwise. Some properties of the eccentricity extended spectral radius 1 are obtained. The eccentricity extended energy Eeex(G) of G is dened. Uper and lower bounds for Eeex(G) are established.

The Effect of Willow Leaf Extracts on Human Leukemic Cells in Vitro

( Hany A. El-Shemy ),( Ahmed M. Aboul Enein ),( Mostafa I. Aboul Enein ),( Sohair I. Issa ),( Kounosuke Fujita ) 생화학분자생물학회 2003 BMB Reports Vol.36 No.4

The young developing leaves of willow (Salix safsaf, Salicaceae) trees have antileukemic activity. After a 24-h incubation in vitro, the crude water extracts of the leaves killed a majority of the blasts of acute myeloid leukemia (AML, 73.8%).