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  • Author: M. A. Amin x
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Studies on Inx(As2Se3)1-x thin films using variable angle spectroscopic ellipsometry (VASE)

Abstract

The results of multi-angle ellipsometrical measurements of thermally evaporated Inx(As2Se3)1-x (x = 0, 0.01,0.05) films are presented. Optical parameters n and Es of thin Inx(As2Se3)1-x films show that indium atoms were incorporated into the host matrix of As2Se3 forming distinct features depending on the indium concentration. Refractive index, n, was found to decrease with the addition of In to the binary As2Se3. The real and imaginary parts of the dielectric function, ε' and ε" were also calculated from the obtained data and correlated with In concentration. It was found that e' decreases with the increase of In content while ε" increases with the increase of In content. Absorption edge is shifted towards lower photon energy with the increase of In content. As a result, the optical energy gap decreases with increasing In content. This has been correlated with the chemical character of the additive as well as with the structural and bonding aspects of the amorphous composition. Nonlinear optical constants (χ(3) and n2) were determined from linear optical parameters using semi-empirical relations in the long wavelength limit.

Open access
Optical and electrical characterization of BixSe1−x thin films

Abstract

Bulk samples of the BixSe1-x system with (x = 0, 5, and 10) were prepared using conventional melt quenching technique. Thin films were then deposited by thermal evaporation technique under high vacuum conditions from the prepared bulk samples. Effect of Bi substitution on surface morphology, electrical and optical properties of BixSe1-x thin films was studied. X-ray diffraction studies showed the formation of nanocrystalline clusters at Bi concentration x = 10. Formation of these clusters resulted in a rough surface which was confirmed by AFM measurements. The film surface was smooth, with RMS roughness of 0.0124 nm for Bi5Se95. For Bi10Se90, the RMS roughness increased to 3.93 nm indicating the formation of Bi2Se3 clusters. A simple hot probe technique showed a transition from p-type to n-type due to Bi incorporation. Charge transport mechanisms were investigated by temperature dependent DC electrical conductivity measurements in the temperature range of 209 K to 313 K. Electrical activation energy (ΔE) of the films with different Bi concentrations was found to exhibit a notable change at the p to n transition. At low temperature, the conduction was in reasonable agreement with Mott’s condition of variable range hopping. Mott parameters and the density of localized states near Fermi level were evaluated and correlated with the structural changes resulting from Bi addition. In addition, a red shift of the optical absorption edge of the films under study caused by Bi-Se substitution was observed. Slight changes in the optical parameters were observed with the γ-irradiation. Addition of Bi atoms could be used to tailor the structural, electrical and optical properties of chalcogenide materials such as junctionless photovoltaic devices.

Open access
Research Note. Prevalence, protein analysis and possible preventive measures against zoonotic anisakid larvae isolated from marine Atherina fish

Summary

Anisakidosis is a zoonotic infection caused by ingestion of raw or undercooked marine fish including Atherina. In some parts of Egypt, the prevalence of anisakid larvae in marine Atherina still, largely, undetermined. Moreover, the currently used procedures are insufficient to avoid human infection. The aim of this study was to identify the prevalence of anisakid larvae in marine Atherina and to test the effect of several treatment procedures on the viability of anisakid larvae. The infection rate of marine Atherina with anisakid larvae was 23.12 %. Anisakid larvae protein revealed molecular weights ranged from 11.5 - 118.5 Kilo Dalton (KDa.). Moreover, freezing at -20 °C for 21 hours (hrs.) as well as vinegar (5 %) treatment for 3 days were the most effective ways to inactivate the larvae. This study states the zoonotic risk of consuming raw or undercooked marine Atherina and highlights the importance of freezing and vinegar treatment in preventing human infection.

Open access
Total and Intra-Abdominal Fat Distribution in Obese Adolescents Using Different Techniques: Anthropometry, BIA And CT

Abstract

Objectives: Assess the association between the anthropometric measurements of obesity, body composition with total and regional fat areas determined by CT in obese adolescents.

Patients and method: 33 obese adolescents and 20 control group were assessed using anthropometry and body composition. CT measured total abdominal, subcutaneous and visceral fat areas.

Results: Anthropometric, body composition and CT findings of fat content were significantly higher in obese adolescents. Visceral obesity estimated by CT in obese adolescents was significantly higher than control group (66.7 % vs. 15 %,). In obese subjects, total abdominal and subcutaneous fat had a significant positive correlation with BMI, waist, hip circumferences and Fat mass, while visceral fat had a significant positive correlation with total abdominal fat and waist circumference. In control subjects, total abdominal and subcutaneous fat had a significant positive correlation with BMI, waist, hip measurements, waist / hip ratio and fat free mass, while visceral fat had a significant positive correlation with BMI, waist, hip measurements, waist/ hip ratio, FM, PBF and total abdominal fat.

Conclusion: CT is useful for diagnosis of visceral abdominal obesity in both obese and non obese subjects. Waist circumference is a good predictor of total abdominal, subcutaneous and visceral fat in obese adolescents.

Open access
Impact of Zinc and Manganese Application to Increase Productivity of Autumn Planted Maize (Zea Mays L.)

Abstract

Micronutrients play a significant role in various plant metabolic processes and are required in much smaller amount by the plants as compared to the macronutrients. An experiment was conducted during 2011, at the Agronomic research area, University of Agriculture, Faisalabad, Pakistan, to investigate the response of autumn planted maize to ZnSO4 and MnSO4 levels (10, 20 and 30 kg ha-1) and in combinations (5 kg ha-1 ZnSO4 + 5 kg ha-1 MnSO4, 10 kg ha-1 ZnSO4 + 10 kg ha-1 MnSO4 and 15 kg ha-1 ZnSO4 + 15 kg ha-1 MnSO4). The randomized complete block design (RCBD) having three replicates was used with plot size of 3 m x 6 m. The crop was planted on ridges 75 cm apart with recommended plant to plant distance of 25 cm. Maximum values for plant height at maturity (225 cm), cob diameter (4.29 cm), number of grains per cob (415), biological yield (20.15 tons ha-1), grain yield (7.42 tons ha-1) and seed protein content (8.96%) were recorded where 15 kg ha-1 ZnSO4 + 15 kg ha-1 MnSO4 was applied.

Open access
Factors Affecting the Performance of Double Chamber Microbial Fuel Cell for Simultaneous Wastewater Treatment and Power Generation

Electricity generation from the readily biodegradable organic substrate (glucose) accompanied by decolorization of azo dye was investigated using a two-chamber microbial fuel cell (MFC). Batch experiments were conducted to study the effect of dye and substrate concentration on MFC performance. Electricity generation was not significantly affected by the azo dye at 300 mg/L, while higher concentrations inhibited electricity generation. The chemical oxygen demand (COD) removal and decolorization of dye containing wastewater used in the MFC were studied at optimum operation conditions in anode and cathode, 57% COD removal and 70% dye removal were achieved. This study also demonstrated the effect of different catholyte solutions, such as KMnO4 and K2Cr2O7 on electricity generation. As a result, KMnO4 solution showed the maximum electricity generation due to its higher standard reduction potential.

Open access
Preparation and Characterization of Spion-CDs as a Multifunctional Fluorescence/Magnetic Resonance Nanoparticle

Abstract

A multifunctional nanoparticle, Super Paramagnetic Iron Oxide Nanoparticle-Carbon Dots (SPION-CDs), for fluorescence and magnetic resonance imaging is introduced. This nanoparticle possesses the magnetic properties of super-paramagnetic iron oxide (SPION) core as well as the fluorescence characteristics of carbon dots (CDs) coated in mesoporous structure. The SPION-CDs were synthesized using a high temperature facile single-pot hydrothermal method. The products were characterized by transmission electron microscopy (TEM), dynamic light scattering (DLS), X-ray diffraction (XRD), UV/vis absorption, vibrating sample magnetometer (VSM). The cytotoxic effect of SPION-CDs on OVCAR-3 cells was also evaluated. The synthesized nanoparticle possesses optimal size, low toxicity and excellent magnetic properties, including super-paramagnetic behavior (Ms = 42 emu g−1). Moreover, in the viewpoint of optical properties, the quantum yield of ~2.4% was obtained and the nanoparticle shows good fluorescence stability for cell-labeling studies. This multifunctional nanoparticle with appropriate characterization is a promising candidate for multimodal fluorescence/magnetic resonance imaging platform.

Open access