Effects of electron injection on the magnetic and magnetocaloric behavior of Sr₂FeMoO₆ double perovskite

Hussain, I.,Anwar, M.S.,Khan, S.N.,Kim, J.W.,Chung, K.C.,Koo, B.H. ELSEVIER SCIENCE 2017 JOURNAL OF ALLOYS AND COMPOUNDS Vol.694 No.-

With the aim of determining and distinguishing the influence of rare-earth doping on the strength of magnetic interactions, magnetic and magnetocaloric properties of Sr<SUB>2-x</SUB>Pr<SUB>x</SUB>FeMoO<SUB>6</SUB> (x = 0.0, 0.1, 0.2, 0.3) double perovskite were investigated. The X-ray diffraction analysis revealed that all the samples crystallized in a tetragonal structure with I4/mmm space group. The temperature dependent magnetization and Arrott analysis suggested a second order of ferromagnetic phase transition in all the synthesized samples. The competing interaction between the electron injection and steric effect resulted in a non-monotonic evolution of the Curie temperature (T<SUB>C</SUB>). In the low Pr doped samples the raising of the Curie temperature is mainly due to the electronic effects while the decrease in T<SUB>C</SUB> observed for higher Pr doping (x = 0.3) is attributed to the steric effects. The magnetization was observed to increase with the increasing Pr doping (up to x = 0.2) indicating a progressive increase in cationic ordering. The magnetic entropy change was evaluated from the measurement of isothermal magnetization with respect to the magnetic field at different temperatures. The maximum magnetic entropy change and the relative cooling power were found to increase with the increasing Pr doping (x @? 0.2). The tunability of magnetization as well as Curie temperature simply by adjusting the dopant concentration and synthesis conditions makes Sr<SUB>2</SUB>FeMoO<SUB>6</SUB> a potential candidate for exploring the new kind of magnetic refrigerants.

Synthesis and analysis of the influence of Eu3+ on the structural, ferromagnetic, dielectric and conductive characteristics of Ni0.4Zn0.45Cu0.15Fe(2-x)EuxO4 composites using conventional double sintering ceramic method

I. N. Esha,Md. Al-Amin,F. T. Z. Toma,Enayet Hossain,M. N. I. Khan,Kazi Hanium Maria 한양대학교 세라믹연구소 2019 Journal of Ceramic Processing Research Vol.20 No.5

Conventional double sintering ceramic method has been followed to prepare a series of Eu substituted Ni0.4Zn0.45Cu0.15Fe(2-x) EuxO4 (NZCFEO) ferrites with x = 0.00, 0.02, 0.04, 0.07, 0.10, 0.12, 0.15. X-ray diffraction peaks confirm the single phase cubic spinel structures of all the samples. The lattice parameter is found to be distorted with the addition of Eu into the samples. X-ray density and bulk density increase with the increase of Eu content. Better crystallization has been obtained with the decreasing porosity as a result of increasing Eu3+ concentration. The dielectric constant of the samples shows a decreasing trend while both AC and DC resistivities are observed to increase with the increase of Eu3+ concentration. The high resistivity offers greater value of the activation energy. Permeability is found to decrease with increasing Eu content. Saturation magnetization changed significantly with Eu3+ concentration. Noteworthy decrease of the Curie temperature is observed with the addition of Eu substituent.

An Efficient Re-keying Scheme for Cluster Based Wireless Sensor Networks

Khan, F. I.,Jameel, H.,Raazi, S. M. K.,Khan, A. M.,Huh, E. N. SPRINGER-VERLAG 2007 Lecture Notes in Computer Science Vol.- No.4706

Structure-based magnetic, electrical and transport properties of Ni–Zn–Co ferrite by V5+ substitution

Hossain M.D.,Khan M.N.I.,Hossain Md Sarowar,Ahned S.J.,Alam M.K.,Liba S.I.,Hakim M.A.,Jamil A.T.M.K. 한국물리학회 2022 Current Applied Physics Vol.43 No.-

This article presents the modification of structure-based magnetic, electronic and transport properties along with the conduction mechanism and its relaxation process in a Ni–Zn–Co ferrite tailored by V5+ substitution at B-site replacing Fe3+ ions. The composition Ni0.7Zn0.2Co0.1Fe2-xVxO4 (0≤ x≤ 0.12) was synthesized by standard solid-state reaction method and all samples were crystallized with a single-phase cubic spinel structure belonging to the Fd3m space group. The lattice constants decreased gradually from 8.3673≽A to 8.3602≽A and the average grain sizes (DSEM) are also decreased from 6.92 μm to 1.99 μm due to V5+ ions substitution at Fe3+ of B-site. However, more than 25% of Fe3+ ions migrate to A-site from B-site due to V5+ substitution at Fe3+ of B-site. In all samples θD does not strictly follow the Anderson’s prediction, rather it monotonically decreases to a low value until x = 0.12. Magnetic phase transition temperature shifted to the lower temperature and the net magnetization (ηeB) decreases due to V5+ substitution in Ni–Zn–Co ferrite. Apart this, during conduction charge carriers should require more energy to jump from one cationic site to other for V5+ substitution in the Ni–Zn–Co ferrite and the activation energy (Ea) is much more higher in V5+ substituted sample. Moreover, long-range interaction with localized relaxation mechanism is observed in V5+ doped samples. The resistance at the grain (Rg) is maximum (243.09 Ω) for the sample x = 0.10 while grain boundary resistance (Rgb) is maximum (5.98×105 Ω) for the sample x = 0.07. However, the higher value of ρdC for x = 0.12 sample ensures to be suitable for electromagnets, transformers, electronic inductors, and at high-frequency applications. Moreover, x = 0.07 sample displays high value of TCR ( -8.6%/K at 418 K) which may be utilized as an infrared detector for night vision bolometer material.

Interaction of Glucagon G-Protein Coupled Receptor with Known Natural Antidiabetic Compounds: Multiscoring <i>In Silico</i> Approach

Baig, M. H.,Ahmad, K.,Hasan, Q.,Khan, M. K. A.,Rao, N. S.,Kamal, M. A.,Choi, I. Hindawi Publishing Corporation 2015 Evidence-based Complementary and Alternative Medic Vol.2015 No.-

<P>Glucagon receptor (GCGR) is a secretin-like (class B) family of G-protein coupled receptors (GPCRs) in humans that plays an important role in elevating the glucose concentration in blood and has thus become one of the promising therapeutic targets for treatment of type 2 diabetes mellitus. GCGR based inhibitors for the treatment of type 2 diabetes are either glucagon neutralizers or small molecular antagonists. Management of diabetes without any side effects is still a challenge to the medical system, and the search for a new and effective natural GCGR antagonist is an important area for the treatment of type 2 diabetes. In the present study, a number of natural compounds containing antidiabetic properties were selected from the literature and their binding potential against GCGR was determined using molecular docking and other<I> in silico</I> approaches. Among all selected natural compounds, curcumin was found to be the most effective compound against GCGR followed by amorfrutin 1 and 4-hydroxyderricin. These compounds were rescored to confirm the accuracy of binding using another scoring function (<I>x</I>-score). The final conclusions were drawn based on the results obtained from the GOLD and <I>x</I>-score. Further experiments were conducted to identify the atomic level interactions of selected compounds with GCGR.</P>

Fabrication of a three-dimensional bone marrow niche-like acute myeloid Leukemia disease model by an automated and controlled process using a robotic multicellular bioprinting system

Dana M. Alhattab,Ioannis Isaioglou,Salwa Alshehri,Zainab N. Khan,Hepi H. Susapto,Yanyan Li,Yara Marghani,Arwa A. Alghuneim,Rubén Díaz-Rúa,Sherin Abdelrahman,Shuroug AL-Bihani,Farid Ahmed,Raed I. Felim 한국생체재료학회 2023 생체재료학회지 Vol.27 No.00

Background Acute myeloid leukemia (AML) is a hematological malignancy that remains a therapeutic challenge due to the high incidence of disease relapse. To better understand resistance mechanisms and identify novel therapies, robust preclinical models mimicking the bone marrow (BM) microenvironment are needed. This study aimed to achieve an automated fabrication process of a three-dimensional (3D) AML disease model that recapitulates the 3D spatial structure of the BM microenvironment and applies to drug screening and investigational studies. Methods To build this model, we investigated a unique class of tetramer peptides with an innate ability to selfassemble into stable hydrogel. An automated robotic bioprinting process was established to fabricate a 3D BM (niche-like) multicellular AML disease model comprised of leukemia cells and the BM’s stromal and endothelial cellular fractions. In addition, monoculture and dual-culture models were also fabricated. Leukemia cell compatibility, functionalities (in vitro and in vivo), and drug assessment studies using our model were performed. In addition, RNAseq and gene expression analysis using TaqMan arrays were also performed on 3D cultured stromal cells and primary leukemia cells. Results The selected peptide hydrogel formed a highly porous network of nanofibers with mechanical properties similar to the BM extracellular matrix. The robotic bioprinter and the novel quadruple coaxial nozzle enabled the automated fabrication of a 3D BM niche-like AML disease model with controlled deposition of multiple cell types into the model. This model supported the viability and growth of primary leukemic, endothelial, and stromal cells and recapitulated cell-cell and cell-ECM interactions. In addition, AML cells in our model possessed quiescent characteristics with improved chemoresistance attributes, resembling more the native conditions as indicated by our in vivo results. Moreover, the whole transcriptome data demonstrated the effect of 3D culture on enhancing BM niche cell characteristics. We identified molecular pathways upregulated in AML cells in our 3D model that might contribute to AML drug resistance and disease relapse. Conclusions Our results demonstrate the importance of developing 3D biomimicry models that closely recapitulate the in vivo conditions to gain deeper insights into drug resistance mechanisms and novel therapy development. These models can also improve personalized medicine by testing patient-specific treatments.

New constituents triterpene ester and sugar derivatives from Panax ginseng Meyer and their evaluation of antioxidant activities

Chung, I.M.,Siddiqui, N.A.,Kim, S.H.,Nagella, P.,Khan, A.A.,Ali, M.,Ahmad, A. Saudi Pharmaceutical Society 2017 Saudi pharmaceutical journal Vol.25 No.5

Panax ginseng C. A. Meyer (Araliaceae), is a well-known herb and used in the old established system of Oriental remedy, especially in Japan, China and Korea. Four new compounds characterized as (cis)- 7β,11α,19,21-tetra-O-decanoyl-18, 22β-dihydroxy-dammar-1-en-3-one (1), 3β,4α,12β-trihydroxystigmast-5-en-21-yl octadecan-9',12'-dienoate (2), dammar-12, 24-dien-3α, 6β, 15α-triol-3α-D-arabinopyranosyl-6β-L-arabinopyranoside (3) and dammar-24-en-3α, 6β, 16α, 20β-tetraol-3α-D-arabinopyranosyl-6β-D-arabinopyranoside (4) were isolated and established from the ethyl acetate and butanol extracts of the roots of P. ginseng. Their structures were established on the basis of spectral data and chemical reactions. Natural compounds indicative a great reservoir of materials and compounds with evolved biological activity, including antioxidant. Compounds 1-4 were investigated in vitro for antioxidant potential using ferric reducing antioxidant power (FRAP), the Nitric oxide (NO) scavenging activity, reducing power, phosphomolybdenum and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging actions, and the decision showed the compounds 3and 4 have probablyessential antioxidant properties than the compounds 1and 2 presented weak activity.

Two-Dimensional Nanosheets Produced by Liquid Exfoliation of Layered Materials

Coleman, J. N.,Lotya, M.,O'Neill, A.,Bergin, S. D.,King, P. J.,Khan, U.,Young, K.,Gaucher, A.,De, S.,Smith, R. J.,Shvets, I. V.,Arora, S. K.,Stanton, G.,Kim, H.-Y.,Lee, K.,Kim, G. T.,Duesberg, G. S.,H American Association for the Advancement of Scienc 2011 Science Vol.331 No.6017

<P>If they could be easily exfoliated, layered materials would become a diverse source of two-dimensional crystals whose properties would be useful in applications ranging from electronics to energy storage. We show that layered compounds such as MoS(2), WS(2), MoSe(2), MoTe(2), TaSe(2), NbSe(2), NiTe(2), BN, and Bi(2)Te(3) can be efficiently dispersed in common solvents and can be deposited as individual flakes or formed into films. Electron microscopy strongly suggests that the material is exfoliated into individual layers. By blending this material with suspensions of other nanomaterials or polymer solutions, we can prepare hybrid dispersions or composites, which can be cast into films. We show that WS(2) and MoS(2) effectively reinforce polymers, whereas WS(2)/carbon nanotube hybrid films have high conductivity, leading to promising thermoelectric properties.</P>

Synthesis of zinc substituted cobalt ferrites via standard double sintering ceramic technique: A study on their structural, magnetic and dielectric properties

Tamanna Mariam,I. N. Esha,M. N. I. Khan,Shamima Choudhury,Kazi Hanium Maria 한양대학교 세라믹연구소 2020 Journal of Ceramic Processing Research Vol.21 No.4

A series of Co1-xZnxFe2O4 ferrites with x = 0.0, 0.1, 0.2, 0.3, 0.4, 0.5 were synthesized using the standard double sinteringceramic technique. The single-phase cubic spinel structure of the samples was confirmed from the X-ray diffraction patternsand the sharp high intensity peak revealed that the samples are in good crystalline form. The lattice parameters were observedto increase with the increasing of Zn concentration. By increasing the concentration of Zn content, a significant increase in thedensity and a subsequent decrease in porosity and grain size were observed. The dielectric constant (ε′) of the sample is foundto decrease with the increase in frequency. Dielectric relaxation peaks were observed for the frequency dependence of dielectricloss curves. The dc resistivity at different temperatures was studied and all the samples were of semiconductor nature. Thesaturation magnetization was found to be reduced as the Zn substitution was increased and consequently permeabilitydecreases.

Slightly acidic electrolyzed water combined with chemical and physical treatments to decontaminate bacteria on fresh fruits

Tango, C.N.,Khan, I.,Ngnitcho Kounkeu, P.F.,Momna, R.,Hussain, M.S.,Oh, D.H. ACADEMIC PRESS LTD 2017 FOOD MICROBIOLOGY Vol.67 No.-

<P>Effect of sequential combination of slightly acidic electrolyzed water (SAEW) with chemical and physical treatments on bacterial decontamination on fruits was investigated in this study. Effect of treatments on microbial and sensory quality was also analyzed after subsequent storage at 4 degrees C and room temperature (RT, 23 +/- 0.15 degrees C). Whole apple and tomato fruits were inoculated with cocktail strains of Escherichia coli O157:H7 and Listeria monocytogenes. Uninoculated and inoculated fruits were washed first with distilled water (DW), calcium oxide (CaO), fumaric acid (FA), and SAEW at RT for 3 min. Combinations were performed by adding treatment one at a time to SAEW as following FA + SAEW, CaO + FA + SAEW, and CaO + FA + SAEW + ultrasonication (US) or microbubbles (MB). All the sanitizer treatments resulted in significant (p < 0.05) bacterial reduction compared to DW used as control. Increasing the treatments in combination from FA + SAEW to CaO + FA + SAEW + US resulted in an increased bacterial decontamination. The cavitation induced by ultrasonication in FA + SAEW solution resulted in a higher additive effect in decontamination of Escherichia coil O157:H7 and Listeria monocytogenes compare to the agitation generated by microbubble generator in FA + SAEW solution. CaO + FA + SAEW and CaO + FA + SAEW + US were effective in improving the microbial safety and quality of apple fruits. However, additional treatment of US impacted on the quality of tomato fruits during storage at RT. Therefore, a combination of SAEW with sanitizers (CaO and FA) and mechanical force (Ultrasonication) has the potential to be used in postharvest sanitation processing in the fresh fruit industry. Published by Elsevier Ltd.</P>