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Some Biochemical Abnormalities Caused by Cypermethrin in adults of Tribolium castaneum (Herbst.)
ASHFAQ, Muhammad,shahid Mehmood KHALID,Waseem AKRAM,Riaz HUSSAIN,이종진 한국곤충학회 2004 Entomological Research Vol.34 No.1
Biochemical effects of sub lethal doses LC10 and LC20 of cypermethrin were studiedon some enzymes and macromolecule activities of adult beetles of Tribolium castaneum (Herbst.).Cypermethrin caused disturbances in levels of all biochemical components under study. The doseof 0.78 ppm caused abnormalities in α-amylase and FAA by increasing their activities i.e.,45.45% and 21.97% significantly. The higher sub lethal dose of 2.62 ppm disturbed all theparameters (AcP, α-amylase, soluble protein and FAA) except AkP, which was decreased by93.06%. Moreover, sub lethal doses either increased or decreased the levels of all parameters nonsignificantlyexcept AkP and FAA which were effected significantly by 87.92% and 14.29% atlower and higher doses, respectively. In the present studies, cypermethrin significantly enhancedthe activity of AkP in both susceptible and resistant strains of T. castaneum adult beetles whileFAA contents were increased significantly in resistant strain only. The activity of α-amylase wassignificantly lowered in susceptible strain only.
Ashfaq AHMAD,배홍섭,이일수 한국물리학회 2019 새물리 Vol.69 No.2
Cobalt zinc ferrite (Co0:6Zn0:4Fe2O) nanoparticles were synthesized using a one-step hydrothermal method. Triethylene glycol (TREG) was used as a biocompatible coating material. The TREGcoated nanoparticles were spherical, with an average diameter of 9.82 nm. The Fourier-transform infrared spectra confirmed the presence of a TREG-coating on the surfaces of the nanoparticles. The particles had a saturation magnetization of 84 emu/g and a coercivity of 32 Oe. The heating capability of the particles was evaluated using an induction system, and the heating curves for aqueous samples with various particle concentrations were obtained. An alternating magnetic field with an amplitude of 4.5 kA/m and a frequency of 216 kHz was applied to the samples. The optimal particle concentration in water for achieving the hyperthermia target temperature of 42 ◦C was 4.58 mg/mL. The specific absorption rate (SAR) of the 2-mg/mL sample was 83 W/g. The linear relationship between the SAR and the square of the field strength was confirmed for a representative 10-mg/mL sample. These findings show that TREG-coated particles are suitable for magnetic hyperthermia applications owing to their superparamagnetic properties and high SAR values.
Solvent-dependent Magnetic Heating of Rod-shaped Iron-oxide Nanoparticles
Ashfaq AHMAD,배홍섭,이일수,홍성욱 한국물리학회 2016 New Physics: Sae Mulli Vol.66 No.3
Rod-shaped iron-oxide (Fe$_{3}$O$_{4}$) nanoparticles were synthesized using a sonochemical method. Transmission electron microscopy revealed that the average width and length of the synthesized nanoparticles were 8 and 40 nm, respectively. An inverse spinel structure of the nanoparticles was inferred from the X-ray diffraction patterns. The iron-oxide nanoparticles were dispersed in water, toluene, or xylene, and the solvent-dependent magnetic-heating effects of the nanoparticles were observed by using an induction heating system. The nanoparticles dispersed in toluene exhibited the highest saturation temperature while the saturation temperature was the smallest for the nanoparticles dispersed in water. These results demonstrate that the heat generated by Brownian relaxation loss is largest for toluene, which has the smallest viscosity among the studied solvents.
Poly(ethyleneglycol)-Coated Ni0.65Zn0.35Fe2O4 Nanoparticles for Hyperthermia Applications
Ashfaq AHMAD,배홍섭,이일수,홍성욱 한국물리학회 2017 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.70 No.6
Poly(ethyleneglycol)-coated Ni-Zn ferrite (Ni0.65Zn0.35Fe2O4) nanoparticles were synthesized in powder form by using the high-temperature polyol method. As shown by X-ray diffraction, the particles exhibited the inverse spinel crystal structure. Transmission electron microscopy analysis revealed that the particles had spherical shapes, with an average diameter of 8.5 nm. The optimum concentration of the nanoparticles in aqueous solution was found to be 0.40 mg/mL. The saturation temperature of this dispersion at a field strength of 4.4 kA/m and a frequency of 260 kHz was 42 C, which is the desired temperature for application of the nanoparticles to magnetic hyperthermia. The specific absorption rate (SAR) of the particles, measured in aqueous solution with a particle concentration of 0.40 mg/mL, was 33.47W/g, indicating their suitable use in magnetic hyperthermia applications. A dependence of the SAR on the square of the magnetic field intensity was also observed.
A Collaborative decision making for distributed detection system
Ashfaq Hussain Farooqi(아쉬팍 후세인 파루키),Wang Jin(왕진),Farrukh Aslam Khan(파루크 아슬람 칸),Sungyoung Lee(이승룡) 한국정보과학회 2011 한국정보과학회 학술발표논문집 Vol.38 No.1D
Intrusion detection systems (IDS) are supposed to be an efficient safety measure against inside attacks. In purely distributed IDS approach, IDS agent is installed in every node. It checks abnormal behavior of neighboring nodes locally. It collects the data that it receives from nodes in its radio range. Sensor nodes audit that data and generate alerts for abnormal activity. Here, there are two ways of taking decision. First, it can take decision individually and second, it can communicate with its neighbor to find the status of the claimed compromised nodes. In this paper, we propose a collaborative decision making scheme for purely distributed detection system. The proposed scheme is light weight compared to consensus based validation methodology. It provides a better scheme to find intrusions by interacting with other nodes.
Ashfaq AHMAD,배홍섭,이일수 한국물리학회 2018 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.73 No.1
Cetyltrimethyl ammonium bromide (CTAB)-coated nickel ferrite (NiFe2O4) nanoparticles were synthesized using the high-temperature thermal decomposition method. The hydrophobic particles became water-soluble after the coating with CTAB, a positively charged ligand. The morphology and the phases of the nanoparticles were characterized using X-ray diffraction and transmission electron microscopy (TEM). TEM images demonstrated that the particles were cube-shaped; the average length of their side was 32.6 nm. Inductively coupled plasma spectroscopy measurements were performed to confirm the chemical composition of the particles. The particles exhibited superparamagnetic behavior with negligible coercive force. Magnetic heating of the aqueous suspensions of nanoparticles was performed in the presence of a radio-frequency magnetic field of 4.4 kA/m at a frequency of 216 kHz. The 1.5-mg/mL sample reached the hyperthermia target temperature of 42 °C and exhibited a high specific absorption rate (SAR) value of 152 W/g. These findings show that the investigated nanoparticles are suitable for magnetic hyperthermia applications and have the advantage of low dosage owing to their high SAR values.
Adnan, Ashfaq,Lam, Robert,Chen, Hanning,Lee, Jessica,Schaffer, Daniel J.,Barnard, Amanda S.,Schatz, George C.,Ho, Dean,Liu, Wing Kam American Chemical Society 2011 Molecular pharmaceutics Vol.8 No.2
<P>In this work, we have combined constant-pH molecular dynamics simulations and experiments to provide a quantitative analysis of pH dependent interactions between doxorubicin hydrochloride (DOX) cancer therapeutic and faceted nanodiamond (ND) nanoparticle carriers. Our study suggests that when a mixture of faceted ND and DOX is dissolved in a solvent, the pH of this solvent plays a controlling role in the adsorption of DOX molecules on the ND. We find that the binding of DOX molecules on ND occurs only at high pH and requires at least ∼10% of ND surface area to be fully titrated for binding to occur. As such, this study reveals important mechanistic insight underlying an ND-based pH-controlled therapeutic platform.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/mpohbp/2011/mpohbp.2011.8.issue-2/mp1002398/production/images/medium/mp-2010-002398_0008.gif'></P>