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Storage Proteins of Diamondback Moth, Plutella xylostella:Purification and Expression Profile
Ahmed M. A. Ibrahim,Keewoo Lee,이혁수,Yonggyun Kim 한국응용곤충학회 2006 Journal of Asia-Pacific Entomology Vol.9 No.2
Storage proteins (SPs) were significantly detected in the hemolymph during the late instar larvae of diamondback moth, Plutella xylostella. These SPs were resolved into three proteins (SP1, SP2, and SP3) at 7% SDS-PAGE. Their apparent molecular sizes were around 80 kDa. SP1 was synthesized later than SP2 and SP3 during the development of the last instar. Total soluble proteins of last instar larvae were extracted and fractionated sequentially with ammonium sulfate, size-exclusion chromatography, and ion-exchange chromatography. The SPs were purified and their developmental expression was discussed.
Vibration analysis of cracked frame structures
Ahmed M. Ibrahim,Hasan Ozturk,Mustafa Sabuncu 국제구조공학회 2013 Structural Engineering and Mechanics, An Int'l Jou Vol.45 No.1
In this study, the effects of crack depth and crack location on the in-plane free vibration of cracked frame structures have been investigated numerically by using the Finite Element Method. For the rectangular cross-section beam, a crack element is developed by using the principles of fracture mechanics. The effects of crack depth and location on the natural frequency of multi-bay and multi-store frame structures are presented in 3D graphs. The comparison between the present work and the results obtained from ANSYS shows a very good agreement.
Ahmed M.A. Ibrahim,Ali M. Ali 한국응용곤충학회 2018 Journal of Asia-Pacific Entomology Vol.21 No.4
The rapid growth of nanotechnology application in various fields of science led to need of understanding their possible effects on development and physiology of insects before using them as control agents. Instead of feeding on a toxic dose, the impact of silver nanoparticles (AgNPs, 50–60 nm) and zinc oxide nanoparticles (ZnONPs, 10–30 nm) was studied at a nonlethal concentration on the larval stages of Spodoptera littoralis. Late second instar larvae of S. littoralis were treated with water, 10 mg/mL AgNPs and ZnONPs dipped castor leaves for 6 days. Both nanoparticles treated leaves caused reduction in both larval weight gain and pupal weight than water dipped leaves while ZnONPs only caused extended larval period. ZnONPs increased total hemocyte, granular cell and plasmatocyte counts while AgNPs increased plasmatocytes only. ZnONPs decreased the levels of protein, lipids and carbohydrates than control and AgNPs treated larvae. On the contrary, ZnONPs induced significant increase in the activities of amylase, glucose 6 phosphate dehydrogenase (G6PD), lipase as well as two antioxidative enzymes, the catalase and superoxide dismutase. These results clearly show that ZnONPs ingestion interfere with the digestive and immunological physiology as well as the development of S. littoralis.
Ahmed M.A. Ibrahim,Lamia A. ALRAKAN,Saleh Ahmed ALAIFAN 한국곤충학회 2015 Entomological Research Vol.45 No.5
Female mosquitoes feed on human blood, which can be collected to analyze human short tandem repeat (STR) sequences; these are specific to each human individual. Analysis of STRs might help in identification of a person found near a crime scene. Aedes aegypti and Culex pipiens mosquitoes fed on human blood were cultured at 18°C or 40°C (median temperature for summer and winter time in Riyadh governorate, Saudi Arabia) for 3, 6, 12, 24, 48 and 72 h. In A. aegypti, human DNA concentration was reduced with time at both temperatures. At 18°C, we obtained full STR profiles up to 48 h post feeding on human blood while none of the 16 loci were obtained at 72 h. At 40°C, we missed six sites at 12 h after blood sucking, 12 at 24 h, and 15 at 48 h and 72 h. In C. pipiens cultured at 18°C, full profiles were developed up to 48 h following blood feeding while we could not amplify five sites at 72 h. At 40°C, mortality among females was 50% at 24 h and 100% at both 48 h and 72 h; however, we had full profiles in all samples including dead insects. This research addressed the possibility of using mosquitoes in forensic research by DNA genotyping by changing the mosquito culturing temperature and mosquito genus. Our findings proved that different types of mosquito change the temporal pattern of STR analysis and showed that the mosquito culturing temperature affects the integrity of DNA for STR analysis.
Storage Proteins of Diamondback Moth, Plutella xylostella: Purification and Expression Profile
Ibrahim Ahmed M.A.,Lee Kee-Woo,Lee Hyuk-Soo,Kim Yong-Gyun Korean Society of Applied Entomology 2006 Journal of Asia-Pacific Entomology Vol.9 No.2
Storage proteins (SPs) were significantly detected in the hemolymph during the late instar larvae of diamondback moth, Plutella xylostella. These SPs were resolved into three proteins (SP1, SP2, and SP3) at 7% SDS-PAGE. Their apparent molecular sizes were around 80 kDa. SP1 was synthesized later than SP2 and SP3 during the development of the last instar. Total soluble proteins of last instar larvae were extracted and fractionated sequentially with ammonium sulfate, size-exclusion chromatography, and ion-exchange chromatography. The SPs were purified and their developmental expression was discussed.
Behaviour and design of guyed pre-stressed concrete poles under downbursts
Ahmed M. Ibrahim,Ashraf A. El Damatty 한국풍공학회 2019 Wind and Structures, An International Journal (WAS Vol.29 No.5
Pre-stressed concrete poles are among the supporting systems used to support transmission lines. It is essential to protect transmission line systems from harsh environmental attacks such as downburst wind events. Typically, these poles are designed to resist synoptic wind loading as current codes do not address high wind events in the form of downbursts. In the current study, the behavior of guyed pre-stressed concrete Transmission lines is studied under downburst loads. To the best of the authors’ knowledge, this study is the first investigation to assess the behaviour of guyed pre-stressed concrete poles under downburst events. Due to the localized nature of those events, identifying the critical locations and parameters leading to peak forces on the poles is a challenging task. To overcome this challenge, an in-house built numerical model is developed incorporating the following: (1) a three-dimensional downburst wind field previously developed and validated using computational fluid dynamics simulations; (2) a computationally efficient analytical technique previously developed and validated to predict the non-linear behaviour of the conductors including the effects of the pretension force, sagging, insulator’s stiffness and the non-uniform distribution of wind loads, and (3) a non-linear finite element model utilized to simulate the structural behaviour of the guyed pre-stressed concrete pole considering material nonlinearity. A parametric study is conducted by varying the downbursts locations relative to the guyed pole while considering three different span values. The results of this parametric study are utilized to identify critical downburst configurations leading to peak straining actions on the pole and the guys. This is followed by comparing the obtained critical load cases to new load cases proposed to ASCE-74 loading committee. A non-linear failure analysis is then conducted for the three considered guyed pre-stressed concrete transmission line systems to determine the downburst jet velocity at which the pole systems fail.
Ibrahim Ahmed M.A.,Choi, Jae-Young,Je, Yeon-Ho,Kim, Young-Gyun Korean Society of Applied Entomology 2005 Journal of Asia-Pacific Entomology Vol.8 No.4
Endoparasitoid wasp, Cotesia plutellae, parasitizes diamondback moth, Plutella xylostella, and interrupts host development and immune processes. Its obligate symbiotic virus, C. plutellae bracovirus (CpBV): has been regarded as a major source of interrupting the physiological alteration during the parasitization. On the process of genome sequencing of CpBV, two putative genes were detected and homologous to E94 of baculovirus and histone H4 subunit of a nucleosome, respectively, The open reading frame of CpBV-$E94{\alpha}$ was 642 bp encoding 214 amino acid residues, while that of CpBV-H4 was 423 bp encoding 141 amino acid residues. Both genes were on the same segment of CpBV genome. They were expressed only in the p. xyiostella parasitized by C, plutellae in which all three tissues of hemocytes, fat body, and gut expressed both genes. Quantitative RT-PCR analyses indicated that their expression patterns in the parasitized host were similar and exhibited bimodal peaks at early and late parasitization periods. We discussed their physiological functions based on the gene structures.
Vibration analysis of cracked frame structures
Ibrahim, Ahmed M.,Ozturk, Hasan,Sabuncu, Mustafa Techno-Press 2013 Structural Engineering and Mechanics, An Int'l Jou Vol.45 No.1
In this study, the effects of crack depth and crack location on the in-plane free vibration of cracked frame structures have been investigated numerically by using the Finite Element Method. For the rectangular cross-section beam, a crack element is developed by using the principles of fracture mechanics. The effects of crack depth and location on the natural frequency of multi-bay and multi-store frame structures are presented in 3D graphs. The comparison between the present work and the results obtained from ANSYS shows a very good agreement.