479 results on '"Siddique, Abu Bakar"'
Search Results
202. Nipah Virus: A Public Health Concern
- Author
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Siddique, Abu Bakar, primary, Fardows, Jannatul, primary, Farhana, Nasreen, primary, and Mazumder, Maksud, primary
- Published
- 2016
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203. Diversity and Composition of the Leaf Mycobiome of Beech (Fagus sylvatica) Are Affected by Local Habitat Conditions and Leaf Biochemistry
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Unterseher, Martin, primary, Siddique, Abu Bakar, additional, Brachmann, Andreas, additional, and Peršoh, Derek, additional
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- 2016
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204. Isolation and Identification of Pathogenic Gram-Positive Bacteria from Egg Shell of Hen and to See Their Antimicrobial Susceptibility Pattern
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Fardows, Jannatul, primary, Siddique, Abu Bakar, primary, Moureen, Adneen, primary, Islam, Tasmin Afroz Binte, primary, Farhana, Nasrin, primary, and Naheen, Chowdhury Rafia, primary
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- 2016
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205. Strong-absorption model analysis of3He scattering
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Rahman, M., Sen Gupta, H. M., Rahman, Md. A., and Siddique, Abu Bakar
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- 1987
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206. 131‐Oxophorbine protopheophorbide A from Ziziphus lotus as a novel mesenchymal‐epithelial transition factor receptor inhibitory lead for the control of breast tumor growth in vitro and in vivo.
- Author
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Souid, Soumaya, Elsayed, Heba E., Ebrahim, Hassan Y., Mohyeldin, Mohamed M., Siddique, Abu Bakar, Karoui, Habib, El Sayed, Khalid A., and Essafi‐Benkhadir, Khadija
- Published
- 2018
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207. Both plant genotype and herbivory shape aspen endophyte communities.
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Albrectsen, Benedicte Riber, Siddique, Abu Bakar, Decker, Vicki Huizu Guo, Unterseher, Martin, and Robinson, Kathryn M.
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PLANT chemical defenses , *ENDOPHYTES , *EUROPEAN aspen , *PLANT genetics , *ENDOPHYTIC fungi - Abstract
Salicinoid phenolic glycosides are common defence substances in salicaceous trees and specialist leaf beetles use these compounds for their own defence against predators. Salicinoids vary qualitatively and qualitatively in aspen (Populus tremula) and this variation has a genetic basis. The foliar endophyte mycobiome is plentiful and we hypothesised that it is related to plant genotype, potentially mediated by salicinoid composition, and that interactions with the leaf beetle Chrysomela tremula may alter this relationship. We studied these three-way interactions in controlled greenhouse experiments. Endophytic fungi were isolated from sterilised leaf tissues with and without beetle damage, and from beetles. We confirmed that endophyte composition was influenced by host genotype. Beetle activity added generalist morphs to the mycobiome that overrode the initial host association. Yeast-like genera (Cryptococcus and Rhodotorula) were isolated only from beetle-damaged tissues and from beetles, whereas fast-growing filamentous fungi dominated beetle-free control plants. Competition experiments between filamentous fungi of plant origin and beetle-related yeasts suggested interaction of both stimulating and inhibiting modes of action amongst the fungi. As a result, we detected examples of amensalism, commensalism, parasitism and competition between the morphs tested, but we found no evidence of mutualism, and consequently no co-evolutionary relationship could be demonstrated, between yeasts carried by beetles, host genotype and associated filamentous morphs. Endophyte studies are method-dependent and high-throughput sequencing technology best define the fungal mycobiome, culturing however continues to be a cheap way to provide fundamental ecological insights and it is also required for experimental studies. [ABSTRACT FROM AUTHOR]
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- 2018
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208. Cost effective synthesis of sulfur and nitrogen co-doped graphene aerogel and application in binder free supercapacitor.
- Author
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Muhiuddin, Mohammad, Khan, Aliullah Zaifullah, Devi, Naorem Aruna, Bharadishettar, Naveen, Meti, Sunil, Siddique, Abu Bakar, Bhat K., Udaya, Akhtar, Waseem, and Rahman, Mohammad Rizwanur
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AEROGELS , *DOPING agents (Chemistry) , *NITROGEN , *GRAPHENE , *SULFUR , *ENERGY density , *GRAPHENE oxide - Abstract
Incorporating heteroatoms into graphene lattice results in enhanced electrical conductivity and electrochemically active sites and has significant importance in developing high-performance supercapacitors. In this study, sulfur and nitrogen co-doped graphene aerogel is synthesized via hydrothermal technique followed by a simple but effective freeze-thawing and ambient pressure drying process (referred to as SN-GA). The process requires low-cost raw materials and cost-effective equipment without the utilization of any special instrument that operates at ultra-low temperatures, under high pressure, or vacuum environment. Ammonium sulfate [(NH4)2SO4] and ethylenediamine are used as a source of sulfur and nitrogen and as a reducing agent. (NH4)2SO4 with different molarities (0, 12, 24, and 36 mM) are used to synthesize four different aerogel samples marked as GA, SN-GA1, SN-GA2, and SN-GA3. The electrode is prepared using an SN-GA2 sample, exhibiting an outstanding specific capacitance of 244 F g−1 at an applied current density of 1 A g−1 with almost 98.5% Coulomb efficiency. Furthermore, based on the SN-GA2 sample, the symmetrical supercapacitor is fabricated, displaying an energy density of 18.14 Wh kg−1 at a power density of 498.4 W kg−1. Hence, SN-GA2 renders a promising material for supercapacitor applications. [ABSTRACT FROM AUTHOR]
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- 2024
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209. Views of the Elderly Regarding the Behavior by His Family Members
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Siddique, Abu Bakar, primary
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- 2015
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210. Awareness on prevention and control of HIV/AIDS among the adults attending an urban hospital in Dhaka
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Hossain, Md Azmal, primary, Begum, Mosammat Makshuda, primary, Hossain, Md Akram, primary, Habib, SM Ahsanul, primary, Siddique, Abu Bakar, primary, and Sarker, Abdus Sattar, primary
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- 2015
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211. In vitro Bioactivities of Three Reputed Medicinal Plants of Bangladesh
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Siddique, Abu Bakar, primary, Islam, Ridwan, primary, Sikder, Md Al Amin, primary, Rashid, Ridwan Bin, primary, Hossian, AKM Nawshad, primary, and Rashid, Mohammad A, primary
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- 2015
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212. Bandwidth efficient multi-level MPPM encoding decoding algorithms for joint brightness-rate control in VLC systems
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Siddique, Abu Bakar, primary and Tahir, Muhammad, additional
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- 2014
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213. Correction: Synthesis of an amantadine-based novel Schiff base and its transition metal complexes as potential ALP, α-amylase, and α-glucosidase inhibitors.
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Ajaz, Aliya, Shaheen, Muhammad Ashraf, Ahmed, Maqsood, Munawar, Khurram Shahzad, Siddique, Abu Bakar, Karim, Abdul, Ahmad, Nazir, Rehman, Muhammad Fayyaz ur, and Mehmood, Tahir
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- 2023
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214. Phytochemical screening and comparative antimicrobial potential of different extracts of Stevia rebaudiana Bertoni leaves
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Siddique, Abu Bakar, primary, Rahman, Syed Mohammad Mizanur, additional, Hossain, Mohammad Amzad, additional, and Rashid, Mohammad Abdur, additional
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- 2014
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215. Joint error-brightness control coding for LED based VLC link
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Siddique, Abu Bakar, primary and Tahir, Muhammad, additional
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- 2014
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216. Joint Rate-Brightness Control using Variable Rate MPPM for LED Based Visible Light Communication Systems
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Siddique, Abu Bakar, primary and Tahir, Muhammad, additional
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- 2013
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217. Optimal Brightness-Rate Control using VR-MPPM and its Spectral Analysis for VLC System
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Tahir, Muhammad, primary and Siddique, Abu Bakar, additional
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- 2012
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218. Joint brightness control and data transmission for visible light communication systems based on white LEDs
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Siddique, Abu Bakar, primary and Tahir, Muhammad, additional
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- 2011
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219. In Silico and In Vitro Studies of 4-Hydroxycoumarin-Based Heterocyclic Enamines as Potential Anti-Tumor Agents.
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Assad, Mediha, Paracha, Rizwan Nasir, Siddique, Abu Bakar, Shaheen, Muhammad Ashraf, Ahmad, Nadeem, Mustaqeem, Muhammad, Kanwal, Fariha, Mustafa, Muhammad Zia Ul, Rehman, Muhammad Fayyaz ur, Fatima, Sumaya, and Lu, Changrui
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ANTINEOPLASTIC agents , *ENAMINES , *MOLECULAR docking , *BINDING energy , *MELTING points , *ULTRAVIOLET-visible spectroscopy - Abstract
The present study reports the one-step synthesis of several 3-formyl-4-hydroxycouramin-derived enamines (4a–4i) in good yields (65–94%). The characterization of the synthesized compounds was carried out via advanced analytical and spectroscopic techniques, such as melting point, electron impact mass spectrometry (EI-MS), 1H-NMR, 13C-NMR, elemental analysis, FTIR, and UV-Visible spectroscopy. The reaction conditions were optimized, and the maximum yield was obtained at 3–4 h of reflux of the reactants, using 2-butanol as a solvent. The potato disc tumor assay was used to assess Agrobacterium tumefaciens-induced tumors to evaluate the anti-tumor activities of compounds (4a–4i), using Vinblastine as a standard drug. The compound 4g showed the lowest IC50 value (1.12 ± 0.2), which is even better than standard Vinblastine (IC50 7.5 ± 0.6). For further insight into their drug actions, an in silico docking of the compounds was also carried out against the CDK-8 protein. The binding energy values of compounds were found to agree with the experimental results. The compounds 4g and 4h showed the best affinities toward protein, with a binding energy value of −6.8 kcal/mol. [ABSTRACT FROM AUTHOR]
- Published
- 2023
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220. Inhibition of in vitro growth of Plasmodium falciparum field isolates mediated by human antibodies to Pf155/RESA and Pf332
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WAHLIN FLYG, BIRGITTA, primary, SIDDIQUE, ABU BAKAR, additional, PERLMANN, PETER, additional, ESPOSITO, FULVIO, additional, and BERZINS, KLAVS, additional
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- 1999
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221. Multi-scale modeling of dislocation motion and interaction: Theory, Plastic Properties, and Boundary Conditions
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Siddique, Abu Bakar
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- Dislocation Dynamics, Plasticity, Multiscale Modeling, Boundary Conditions, Mechanical Engineering
- Abstract
Dislocation theory is the fundamental tool for explaining plasticity in the material. The elastic field of a material is always influenced by the presence of dislocations and other defects independent of the loading configurations. Scientists and researchers have minimal success in solving plasticity problems analytically. And for this reason, the capturing of dislocation dynamics is highly dependent on numerical modeling, which is always a challenge for its inherent multi-scale nature. Current research investigates and develops self-consistent numerical models for different plasticity problems based on the distributed-dislocation technique and the collocation-point method. Numerical methods are developed for different boundary conditions in the presence of crystal dislocations and discontinuities in the material. Boundary conditions due to the discontinuity in the material are satisfied by placing image or fictitious dislocations or dislocations of unknown Burgers vectors at predefined places. On the free surfaces, some designated points are selected (termed as “collocation points”) to enforce the boundary conditions there only. Numerical models are developed to satisfy the boundary conditions at those collocation points, assuming that satisfying the boundary conditions at those collocation points is sufficient to capture the field solution of the problem. Burgers vectors of those fictitious dislocations are solved for using a system of linear equations that ensures the tractions on the collocation points are zero. It is evident from the assumption that the numerical solution improves as the number of collocation points on the free surfaces increases. The developed numerical scheme is implemented in one of the existing Dislocation Dynamics (DD) codes by Zbib et al. to show the free surface effect in a constant strain-rate simulation. The applications extend to free surfaces with complex geometry and can thus capture the interaction of multiple voids of any geometry. Other studies tackled the singular behavior near the dislocation core, the effect of multiple dislocations or multipoles on the plasticity of the material as well as the effect of solute atoms on both the elastic and plastic behavior of metallic crystalline materials.
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- 2022
222. Critical investigation of up-conversion and dual emission from nitrogen functionalized graphene quantum dots.
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Siddique, Abu Bakar, Mukhuti, Kingshuk, Choudhury, Subhrangshu, Pramanick, Ashit Kumar, Hossain, Syed Minhaz, and Ray, Mallar
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QUANTUM dots , *LIGHT sources , *GRAPHENE , *FEMTOSECOND lasers , *PULSED lasers - Abstract
Up-conversion photoluminescence (UCPL) and dual-band photoluminescence (DBPL) are two widely-reported, exotic properties of graphene quantum dots (GQDs). However, both these phenomena can be associated with measurement artefacts. In case of excitation with monochromatic radiation derived from a white light source, the second order of the excitation or the emission signal can cause misleading impressions of UCPL and DBPL. Laser excitations can also generate spurious UCPL and/or DBPL signals due to leaking radiations. Using a spatially separated femtosecond pulsed laser, we find that in nitrogen-functionalized GQDs there is no evidence for DBPL although a real UCPL is hidden behind spurious signals. [Display omitted] • NGQDs exhibit UCPL in the blue-green region under concentrated pulsed excitation. • UCPL in NGQDs may be attributed to two-photon processes. • Misleading signatures of DBPL arise due to measurement artefacts. • Spurious UCPL and DBPL signals should be eliminated by careful experimentation. [ABSTRACT FROM AUTHOR]
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- 2022
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223. In Vitro Antimicrobial Screening of Four Reputed Bangladeshi Medicinal Plants.
- Author
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Sikdera, Al Amin, Hossian, A. K. M. Nawshad, Siddique, Abu Bakar, Ahmed, Mehreen, Kaisar, Mohammad A., and Rashid, Mohammad A.
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ANTI-infective agents ,MEDICINAL plants ,HYDNOCARPUS ,BIGNONIACEAE ,SANSEVIERIA trifasciata - Abstract
The antimicrobial activity of extractives of different plants has been recognized for many years. In present study the crude methanolic extracts and their kupchan partitioning fractions of four medicinal plants of Bangladesh namely, Sansevieria trifasciata (Fam: Asparagaceae), Justicia gendarussa (Fam: Acanthaceae), Hydnocarpus kurzii (Fam: Achariaceae) and Kigelia pinnata (Fam: Bignoniaceae) were investigated for their in vitro antimicrobial properties. All fractions were tested against 11 different gram positive and gram negative bacteria by the disc diffusion technique for bacteria, where kanamycin (30 µg/disc) disk used as standard. Among the extractives, the methanol extract and their pet-ether, carbon tetrachloride and chloroform soluble kupchan fractions of leaf extract of H. kurzii, and the aerial part extract of S. trifasciata showed significant antibacterial activity, where as chloroform soluble extracts of leaves of H. kurzii revealed highest activity against Vibrio mimicus (15.00 mm) and the methnol extract of whole plant of S. trifasciata demonstrated highest activity against V. mimicus (14.67 mm). The chloroform soluble fractions of J. gendarussa also showed mild to moderate antimicrobial activity with zone of inhibition ranging from 8.33-13.00 mm, in which highest activity was seen against Shigella boydii (13.00 mm). All the extractives of K. pinnata, on the other hand, demonstrated mild antimicrobial activity, where highest zone of inhibition was displayed by the chloroform soluble extract against S. boydii (11.00 mm) and Pseudomonas aeruginosa (11.00 mm). [ABSTRACT FROM AUTHOR]
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- 2011
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224. Inhibition of in vitro growth ofPlasmodium falciparum field isolates mediated by human antibodies to Pf155/RESA and Pf332.
- Author
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WÅHLIN FLYG, BIRGITTA, SIDDIQUE, ABU BAKAR, PERLMANN, PETER, ESPOSITO, FULVIO, and BERZINS, KLAVS
- Subjects
- *
PLASMODIUM falciparum , *IMMUNOGLOBULINS , *MALARIA immunology - Abstract
The capacity of antibodies to interfere with Plasmodium falciparum growth in in vitro cultures is considered to reflect some of their potential protective effects in vivo. Almost all previous analyses of antibody mediated inhibition of parasite growth in vitro were performed with different laboratory strains of P. falciparum. This study was performed to investigate if the long-term culturing of parasites has any effect on their susceptibility to such growth inhibition. The growth inhibitory effects of human antibodies to the vaccine candidate antigens Pf155/RESA and Pf332 on fresh field isolates from children in Burkina Faso were analysed and compared with their effect on an established laboratory strain of the parasite. Although there was variation in the inhibition titres between different isolates tested against one antibody preparation, the differences in inhibition capacity for the three different antibodies were highly significant. No correlation was found between serum levels of anti-Pf155/RESA or -Pf332 antibodies and sensitivity of the corresponding parasite isolates to antibody mediated growth inhibition. [ABSTRACT FROM AUTHOR]
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- 1999
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225. The Effect of Multipoles on the Elasto-Plastic Properties of a Crystal: Theory and Three-Dimensional Dislocation Dynamics Modeling
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Siddique, Abu Bakar, Lim, Hojun, and Khraishi, Tariq A.
- Abstract
Plastic deformation in metals is dominated by the interactions among dislocations and other defects inside the crystal. A large number of dislocation multipoles (dipoles, tripoles, quadrupoles, etc.) can form during plastic deformation. Depending on the relative position and the orientation of the dislocations, interactions in and between multipoles can change the elastoplastic properties of a material. The authors of this article investigate the effect of dislocation multipoles on the elastoplastic properties of a material. This is performed analytically under different multipole configurations (i.e., the distance between active glide planes and the signs of the dislocations) as well as using a three-dimensional discrete dislocation dynamics (DDD) code. The simulations show that multipoles exhibit a hardening/softening effect when the sign of the dislocations involved is the same, and a hardening effect only when the dislocations are of opposite sign to nearby ones. The distance between the two neighboring dislocations was also affecting the proportional limit (PL) for the material. Such hardening or flow stress (FS) results, as in this study, can be incorporated into larger-scale modeling work.
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- 2022
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226. Amorphous carbon dot and chitosan based composites as fluorescent inks and luminescent films.
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Siddique, Abu Bakar, Singh, Vishwa Pratap, Pramanick, Ashit Kumar, and Ray, Mallar
- Subjects
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AMORPHOUS carbon , *QUANTUM dots , *GLASS transition temperature , *AGGLOMERATION (Materials) , *OPTICAL films , *VISIBLE spectra , *CRYSTAL structure - Abstract
A composite of self-passivated amorphous carbon dots (CDs) and chitosan has been developed and utilized to form fluorescent inks and luminescent films. The ink is invisible under visible light but glows brightly under external excitation. Cross-linking between the numerous surface groups present in the highly disordered CDs and chitosan, endow the inks and films with enhanced optical and mechanical properties. The amorphous CD based ink is capable of writing on nearly all types of surfaces and exhibits excellent anti-clogging and anti-smearing properties. The luminescent films on the other hand are characterized by good mechanical strength (σ UTS ≈ 61.3 MPa) along with high luminescence efficiency. The luminescence yield, ultimate tensile stress, hydrophobicity and glass transition temperature of the films were found to scale similarly with the concentration of CDs in chitosan. All the parameters initially improved with increasing CD concentration but then deteriorated beyond some optimal CD loading due to agglomeration effect. We demonstrate that the amorphous carbon dot-based inks and films outperform all other carbon-based fluorescent inks and films prepared from the more expensive crystalline structures. Image 1 • Amorphous CD-chitosan composite based luminescent inks and fluorescent films are developed. • Superior optical and mechanical properties of the inks and the films are demonstrated. • Insights into the mechanism of light emission from carbon nanostructures gained. [ABSTRACT FROM AUTHOR]
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- 2020
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227. Design, synthesis, and validation of novel nitrogen-based chalcone analogs against triple negative breast cancer.
- Author
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Elkhalifa, Dana, Siddique, Abu Bakar, Qusa, Mohammed, Cyprian, Farhan S., El Sayed, Khalid, Alali, Feras, Al Moustafa, Ala-Eddin, and Khalil, Ashraf
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CHALCONE , *TRIPLE-negative breast cancer , *CHORIOALLANTOIS , *CELL growth , *BCL-2 proteins , *NITROGEN mustards , *FORMYLATION - Abstract
Great strides have been made in triple negative breast cancer (TNBC) treatment, which represents 20% of total predicted annual US breast cancer (BC) cases. Despite the development of several therapeutics, TNBC patients have poor overall survival rate, compared to other BC patients, justifying the urgent need to discover new entities for use to control TNBC. Chalcones are important natural products with diverse bioactivities including anticancer effects. This study aimed to design, synthesize and validate novel chalcone leads as potential therapies for TNBC. Fourteen novel chalcone analogs were designed and synthesized comprising alicyclic amines (pyrrolidine, morpholine and piperidine) or nitrogen mustard (Bis -(2-chloroethyl) amine) substituents. Among them, compound 14 ((E)-3-(4-(Bis (2-chloroethyl) amino) phenyl)-1-(3-methoxyphenyl) prop-2-en-1-one) was identified as the most effective against TNBC and other BC phenotypes, with anti-proliferative IC 50 values ranging between 3.94 and 9.22 μM against the TNBC cell lines MDA-MB-231 and MDA-MB-468, as well as against the estrogen positive MCF-7 cell line. Chalcone 14 effectively suppressed the colony formation capacity of MDA-MB-231, MDA-MB-468, and MCF-7 cell lines at 5 and 10 μM treatment concentrations. Furthermore, compound 14 has significantly inhibited cell invasion and migration of MDA-MB-231 and MCF-7 BC cell lines. Additionally, compound 14 had significantly promoted apoptosis by upregulating BAX and downregulating Bcl-2 proteins. Compound 14 induced significant cell cycle arrest of TNBC cells at the G2/M phase. It also induced a reversal of Epithelial Mesenchymal Transition (EMT) by upregulating the epithelial markers E-cadherin and Pan-cadherin and downregulating FAK. Furthermore, it had dramatically diminished new vessel formation (vasculogenesis) in chick chorioallantoic membrane (CAM) model by 60.20 ± 8.47%. Chalcone 14 inhibited 46.41 ± 0.71% of the TNBC MAD-MB-231 cells growth in a nude mouse orthotopic xenograft model in comparison with vehicle control treated animals. Collectively, this study results propose chalcone 14 as a promising lead molecule for the control of TNBC as well as other breast cancer phenotypes. Image 1 • Fourteen novel chalcone analogs were designed as potential treatment for TNBC. • They showed antiproliferative activity with micromolar potency. • Compound 14 had potently inhibited tumor invasion and migration in TNBC. • It induced cell cycle arrest and had significantly promoted apoptosis. • It inhibited tumor growth in nude mice xenografted with MADMB-231 cells by 46.41 ± 0.71% as compared to the control. [ABSTRACT FROM AUTHOR]
- Published
- 2020
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228. Optimization of Taste-Masked (–)-Oleocanthal Effervescent Formulation with Potent Breast Cancer Progression and Recurrence Suppressive Activities.
- Author
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Tajmim, Afsana, Siddique, Abu Bakar, and El Sayed, Khalid
- Subjects
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CANCER relapse , *BREAST cancer , *CANCER invasiveness , *TASTE , *ELECTRONIC tongues , *DIFFERENTIAL scanning calorimetry - Abstract
S-(–)-Oleocanthal (OC), a naturally occurring phenolic secoiridoid exclusively found in extra-virgin olive oil (EVOO), is a potential nutraceutical therapeutic for inflammation, neurodegenerative diseases, and many malignancies, especially breast cancer (BC). The oral delivery of OC is challenging because of its irritative, bitter, and pungent taste and exceptional chemistry, including two reactive aldehydes, phenolic, and ester groups. OC irritation did not correlate with CO2-induced irritation, and hence, OC was not exerting generalized acid-sensing irritation. The objective of this study was to develop an effervescent formulation of OC with an effective CO2-induced masked taste maintaining the efficacy against the estrogen receptor (ER) and HER2 positive BC. Several ratios of acid and carbonate sources were screened, and five effervescent formulations EF1-EF5 were selected and prepared based on their pH and effervescence time. OC formulations were characterized using differential scanning calorimetry, FT-IR spectroscopy, and scanning electron microscopy analyses. OC formulations exhibited acceptable flowability and effervescence time. Based on physical characteristics and improved OC release, formulation EF-2 was selected for subsequent studies. EF-2 showed effective OC taste masking, as suggested by electronic artificial tongue and mouse preference tests. EF-2 suppressed more than 70% of the hormone and HER2-positive BT-474 BC cell growth in a nude mouse xenograft model. Furthermore, EF-2 demonstrated significant inhibition of BT-474 tumor cell locoregional recurrence after primary tumor surgical excision. EF-2-treated mouse sera had significantly reduced CA 15-3 levels, the human BC recurrence marker, compared to the placebo control group at the end of the study. These results highlight the potential of the OC formulation EF-2 as a prospective nutraceutical for the control and prevention of ER+/HER+ BC progression and locoregional recurrence. [ABSTRACT FROM AUTHOR]
- Published
- 2019
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229. (−)-Oleocanthal Combined with Lapatinib Treatment Synergized against HER-2 Positive Breast Cancer In Vitro and In Vivo.
- Author
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Siddique, Abu Bakar, Ebrahim, Hassan Y., Akl, Mohamed R., Ayoub, Nehad M., Goda, Amira A., Mohyeldin, Mohamed M., Nagumalli, Suresh K., Hananeh, Wael M., Liu, Yong-Yu, Meyer, Sharon A., and El Sayed, Khalid A.
- Abstract
Dysregulation of epidermal growth factor receptor (EGFR)/human epidermal growth factor-2 (HER2) family is a hallmark of aggressive breast cancer. Small-molecule tyrosine kinase inhibitors are among the most effective cancer targeted treatments. (−)-Oleocanthal (OC) is a naturally occurring phenolic secoiridoid lead from extra-virgin olive oil with documented anti-cancer activities via targeting mesenchymal epithelial transition factor (c-Met). Dysregulation of c-Met promotes aggressiveness to breast cancer-targeted therapies. Lapatinib (LP) is an FDA-approved dual EGFR/HER2 inhibitor for HER2-amplified breast cancer. HER2-Positive tumor cells can escape targeted therapies like LP effects by overexpressing c-Met. Combined OC-LP treatment is hypothesized to be mechanistically synergistic against HER2-overexpressing breast cancer. Combined sub-effective treatments of OC-LP resulted in synergistic anti-proliferative effects against the HER2-positive BT-474 and SK-BR-3 breast cancer cell lines, compared to OC or LP monotherapy. Antibody array and Western blot analysis showed that combined OC-LP treatment significantly inhibited EGFR, HER2, and c-Met receptor activation, as well as multiple downstream signaling proteins, compared to individual OC or LP treatment. OC-LP Combination significantly inhibited invasion and migration of breast cancer cells through reduced activation of focal adhesion kinase (FAK) and paxillin. Combined treatment of OC-10 mg/kg with LP-12.5 mg/kg suppressed more than 90% of BT-474 tumor cells growth in a nude mouse xenograft model, compared to individual OC or LP treatment. Activated c-Met, EGFR, HER2, and protein kinase B (AKT) were significantly suppressed in combination-treated mice tumors, compared to OC or LP monotherapy. This study reveals the OC future potential as combination therapy to sensitize HER2-overexpressing breast cancers and significantly reduce required doses of targeted HER family therapeutics. [ABSTRACT FROM AUTHOR]
- Published
- 2019
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- View/download PDF
230. Airborne eDNA captures the diversity and dynamics of a subarctic ecosystem across three decades
- Author
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Karlsson, Edvin, Sullivan, Alexis R., Svensson, Daniel, Bellieny-Rabelo, Daniel, Siddique, Abu Bakar, Villegas, José Antonio, Johansson, Anna-Mia, Grahn, Håkan, Sundell, David, Brindefalk, Björn, Norman, Anita, Sjödin, Andreas, Singh, Navinder J., Brodin, Tomas, Forsman, Mats, Stenberg, Per, Karlsson, Edvin, Sullivan, Alexis R., Svensson, Daniel, Bellieny-Rabelo, Daniel, Siddique, Abu Bakar, Villegas, José Antonio, Johansson, Anna-Mia, Grahn, Håkan, Sundell, David, Brindefalk, Björn, Norman, Anita, Sjödin, Andreas, Singh, Navinder J., Brodin, Tomas, Forsman, Mats, and Stenberg, Per
231. Abdominal Pregnancy Implanted in the Spleen: A Case Report
- Author
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Siddiqui, Md Nure Alom, primary, Islam, Md Tohurul, primary, Siddiqua, Fatema, primary, Sultana, Shahnaj, primary, and Siddique, Abu Bakar, primary
- Published
- 1970
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232. A dislocation near a cylindrical hole: A numerical treatment
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Siddique, Abu Bakar, primary and Khraishi, Tariq, additional
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233. Graviola (Annona muricata) Exerts Anti-Proliferative, Anti-Clonogenic and Pro-Apoptotic Effects in Human Non-Melanoma Skin Cancer UW-BCC1 and A431 Cells In Vitro: Involvement of Hedgehog Signaling.
- Author
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Chamcheu, Jean Christopher, Rady, Islam, Chamcheu, Roxane-Cherille N., Siddique, Abu Bakar, Bloch, Melissa B., Banang Mbeumi, Sergette, Babatunde, Abiola S., Uddin, Mohammad B., Noubissi, Felicite K., Jurutka, Peter W., Liu, Yong-Yu, Spiegelman, Vladimir S., Whitfield, G. Kerr, and El Sayed, Khalid A.
- Subjects
SKIN cancer ,MORTALITY ,CANCER invasiveness ,POLYKETIDES ,DICHLOROMETHANE - Abstract
Non-melanoma skin cancers (NMSCs) are the leading cause of skin cancer-related morbidity and mortality. Effective strategies are needed to control NMSC occurrence and progression. Non-toxic, plant-derived extracts have been shown to exert multiple anti-cancer effects. Graviola (
Annona muricata ), a tropical fruit-bearing plant, has been used in traditional medicine against multiple human diseases including cancer. The current study investigated the effects of graviola leaf and stem extract (GLSE) and its solvent-extracted fractions on two human NMSC cell lines, UW-BCC1 and A431. GLSE was found to: (i) dose-dependently suppress UW-BCC1 and A431 cell growth, motility, wound closure, and clonogenicity; (ii) induce G0 /G1 cell cycle arrest by downregulating cyclin/cdk factors while upregulating cdk inhibitors, and (iii) induce apoptosis as evidenced by cleavage of caspases-3, -8 and PARP. Further, GLSE suppressed levels of activated hedgehog (Hh) pathway components Smo, Gli 1/2, and Shh while inducing SuFu. GLSE also decreased the expression of pro-apoptotic protein Bax while decreasing the expression of the anti-apoptotic protein Bcl-2. We determined that these activities were concentrated in an acetogenin/alkaloid-rich dichloromethane subfraction of GLSE. Our data identify graviola extracts and their constituents as promising sources for new chemopreventive and therapeutic agent(s) to be further developed for the control of NMSCs. [ABSTRACT FROM AUTHOR]- Published
- 2018
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234. The Maxi-K (BK) Channel Antagonist Penitrem A as a Novel Breast Cancer-Targeted Therapeutic.
- Author
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Goda, Amira A., Siddique, Abu Bakar, El Sayed, Khalid A., Mohyeldin, Mohamed, and Ayoub, Nehad M.
- Abstract
Breast cancer (BC) is a heterogeneous disease with different molecular subtypes. The high conductance calcium-activated potassium channels (BK, Maxi-K channels) play an important role in the survival of some BC phenotypes, via membrane hyperpolarization and regulation of cell cycle. BK channels have been implicated in BC cell proliferation and invasion. Penitrems are indole diterpene alkaloids produced by various terrestrial and marine
Penicillium species. Penitrem A (1 ) is a selective BK channel antagonist with reported antiproliferative and anti-invasive activities against multiple malignancies, including BC. This study reports the high expression of BK channel in different BC subtypes. In silico BK channel binding affinity correlates with the antiproliferative activities of selected penitrem analogs.1 showed the best binding fitting at multiple BK channel crystal structures, targeting the calcium-sensing aspartic acid moieties at the calcium bowel and calcium binding sites. Further,1 reduced the levels of BK channel expression and increased expression of TNF-α in different BC cell types. Penitrem A (1 ) induced G1 cell cycle arrest of BC cells, and induced upregulation of the arrest protein p27. Combination treatment of1 with targeted anti-HER drugs resulted in synergistic antiproliferative activity, which was associated with reduced EGFR and HER2 receptor activation, as well as reduced active forms of AKT and STAT3. Collectively, the BK channel antagonists represented by penitrem A can be novel sensitizing, chemotherapeutics synergizing, and therapeutic agents for targeted BC therapy. [ABSTRACT FROM AUTHOR]- Published
- 2018
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235. Waste-derived nanobiochar: A new avenue towards sustainable agriculture, environment, and circular bioeconomy.
- Author
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Sani, Md. Nasir Hossain, Amin, Mehedi, Siddique, Abu Bakar, Nasif, Saifullah Omar, Ghaley, Bhim Bahadur, Ge, Liya, Wang, Feng, and Yong, Jean Wan Hong
- Published
- 2023
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236. Milder Autumns May Increase Risk for Infection of Crops with Turnip Yellows Virus.
- Author
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Puthanveed, Vinitha, Singh, Khushwant, Poimenopoulou, Efstratia, Pettersson, Josefin, Siddique, Abu Bakar, and Kvarnheden, Anders
- Subjects
- *
PHYTOPLASMAS , *AUTUMN , *RAPESEED , *GREEN peach aphid , *BEETS , *PEACH , *CROPS , *SUGAR beets - Abstract
Climate change has increased the risk for infection of crops with insect-transmitted viruses. Mild autumns provide prolonged active periods to insects, which may spread viruses to winter crops. In autumn 2018, green peach aphids (Myzus persicae) were found in suction traps in southern Sweden that presented infection risk for winter oilseed rape (OSR; Brassica napus) with turnip yellows virus (TuYV). A survey was carried out in spring 2019 with random leaf samples from 46 OSR fields in southern and central Sweden using DAS-ELISA, and TuYV was detected in all fields except one. In the counties of Skåne, Kalmar, and Östergötland, the average incidence of TuYV-infected plants was 75%, and the incidence reached 100% for nine fields. Sequence analyses of the coat protein gene revealed a close relationship between TuYV isolates from Sweden and other parts of the world. High-throughput sequencing for one of the OSR samples confirmed the presence of TuYV and revealed coinfection with TuYV-associated RNA. Molecular analyses of seven sugar beet (Beta vulgaris) plants with yellowing, collected in 2019, revealed that two of them were infected by TuYV, together with two other poleroviruses: beet mild yellowing virus and beet chlorosis virus. The presence of TuYV in sugar beet suggests a spillover from other hosts. Poleroviruses are prone to recombination, and mixed infection with three poleroviruses in the same plant poses a risk for the emergence of new polerovirus genotypes. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
237. Effects of seed production environment and post harvest management on seed production, viability and vigour of seeds of pea and flax
- Author
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Siddique, Abu Bakar
- Subjects
- 630, Agronomy
- Published
- 2001
238. Exploring the possibility of a people centred development (PCD) process in Rajoir Thana in Bangladesh
- Author
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Siddique, Abu Bakar
- Subjects
- 301, Poor; Empowerment; Participation
- Published
- 1999
239. Methane production from locally available ruminant feedstuffs in Ethiopia – An in vitro study.
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Bekele, Wondimagegne, Huhtanen, Pekka, Zegeye, Abiy, Simachew, Addis, Siddique, Abu Bakar, Albrectsen, Benedicte Riber, and Ramin, Mohammad
- Subjects
- *
BREWER'S spent grain , *CROP residues , *INDIGENOUS plants , *HERBACEOUS plants , *RUMINANTS - Abstract
Achieving optimal nutrient composition in locally sourced ruminant feeds is important, but can be challenging in resource-limited production systems. For example, improving the composition of available local feed resources is a key obstacle to efficiently mitigating enteric methane (CH 4) emissions in ruminants. This study characterized the nutritional content and in vitro methane (CH 4) yield of ruminant feedstuffs accessible in Ethiopia. A survey of 60 experienced farmers in two representative districts in Amhara region, Ethiopia, provided 33 feed samples, which were classified into four ruminant feed categories: Grasses (n=10); indigenous plants (trees, shrubs, herbaceous plants) (n=13); crop residues (n=5); and agro-industrial by-products (n=5). Nutritional composition was assessed by proximate and detergent methods. Methane yield (g CH 4 /kg feed dry matter (DM)) and total gas yield (L/kg DM) were evaluated using a fully automated in vitro gas production system. A colorimetric assay was conducted to measure condensed tannin content (CT, mg/g) in relevant feeds. Lower crude protein (CP) values were observed for the grass (mean 65.2 g/kg DM) and crop residues (mean 54.5 g/kg DM) categories. Agro-industrial by-products had the highest CP (mean 260 g/kg DM), while indigenous plants exhibited intermediate levels (163 g/kg DM). There was significant variation in CH 4 yield (P<0.01) between grasses (12.4–24.7 g/kg DM) indigenous plants (1.8–19.3 g/kg DM), and agro-industrial by-products (8.1–26.9 g/kg DM). The indigenous plant Trifolium acaule gave the lowest in vitro CH 4 yield (1.8 g/kg DM). A positive relationship was observed between in vitro dry matter digestibility (IVDMD), CH 4 , and total gas yield. Percentage of CH 4 in total gas production varied with feed category (grasses 14.5–19.6%; indigenous plants 3.1–16.9%; crop residues 15.8–20.6%; agro-industrial by-products 12.8–18.7%), and within category, e.g., Trifolium acaule (3.1%), Acacia nilotica L. (7.1%), Ziziphus spina-christi (9.9%), brewer's spent grains (BSG) (12.8%), local liquor (areki) residues (14.1%), and local beer (tella) residues (15.1%). A negative relationship was observed between CT content and in vitro CH 4 yield, with a stronger (P<0.05) correlation for soluble CTs (R2 = 0.46) than cell-bound CTs (R2 = 0.25) and total CTs (R2 = 0.29). Based on methanogenic properties and effects of CTs on in vitro CH 4 yield, indigenous plants should be prioritized in ruminant rations in Ethiopia. Making nutritional composition and CH 4 data publicly available could help develop environmentally sound, cost-effective rations for ruminant livestock, benefiting local farmers and leading to more sustainable and efficient livestock production in Ethiopia. • The grass and crop residues are poor in nutrient composition. • Trees, shrubs, and herbaceous plants are ideal feed for resource-limited areas. • Non-grass plants produce more CH 4 than agro-industrial by-products and crop residue. • The higher the digestible feed, the higher the CH 4 and gas yield observed. • Phenolic compounds like soluble condensed tannins had pronounced effects on CH 4 and gas yield. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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240. Facile and rapid method to synthesis sulfur and nitrogen co-doped graphene quantum dots as an electrode material with excellent specific capacitance for supercapacitors application.
- Author
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Muhiuddin, Mohammad, Devi, Naorem Aruna, Bharadishettar, Naveen, Meti, Sunil, Siddique, Abu Bakar, Satyanarayan, M.N., Udaya, Bhat.K., Akhtar, Waseem, and Rahman, Mohammad Rizwanur
- Subjects
- *
QUANTUM dots , *SUPERCAPACITORS , *ENERGY density , *DOPING agents (Chemistry) , *GRAPHENE synthesis , *POWER density , *ELECTRIC capacity , *SUPERCAPACITOR electrodes - Abstract
The current invention pertains to the expeditious simple synthesis of electrode materials that improve the storage capacity of supercapacitors (SCs). Sulfur and nitrogen co-doped graphene quantum dots (SN-GQDs) are synthesized using a microwave-assisted hydrothermal (MAH) process at low pressure and with a short reaction time. The utilization of SN-GQDs in conjunction with Polyaniline (PANI) has the potential to enhance the supercapacitor's energy and power density, owing to their notable specific capacitance. Implementing SN-GQDs material as an SCs electrode, exhibiting an outstanding specific capacitance of 1040 F/g at an applied current density of 0.5 A g−1. Furthermore, a composite of SN-GQDs/PANI is synthesized and the electrochemical performance is compared with the as-synthesized PANI. The symmetrical SCs are fabricated using SN-GQDs/PANI composite, and PANI. At a current density of 0.5 A g−1 SN-GQDs/PANI composite-based SC displays a superior energy density of 44.25 Wh/kg at a power density of 1.227 kW/kg. This is high in comparison to PANI-based SC which shows an energy density of 18.71 Wh/kg at 0.8 kW/kg power density at the same current density. The SC created using SN-GQDs/PANI composite exhibits superior properties and is a promising material for SC applications. [Display omitted] • A cost-effective method is developed to synthesize around 10 nm size of SN-GQDs. • Synthesis of SN-GQDs requires low temperature, low pressure, and a very short time. • C s of electrode prepared from SN-GQDs shows 1040 F/g at 0.5 A g−1. • SN-GQDs/PANI raised SCs energy density 94 % over PANI. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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241. Cyperus scariosus extract based greenly synthesized gold nanoparticles as colorimetric nanoprobe for Ni2+ detection and as antibacterial and photocatalytic agent.
- Author
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Ejaz, Aamir, Mamtaz, Zainab, Yasmin, Iram, Shaban, Muhammad, Siddique, Abu Bakar, Irfan, Muhammad Imran, Ali, Akbar, Muhammad, Shabbir, Sameeh, Manal Y., and Abbas, Azhar
- Subjects
- *
GOLD nanoparticles , *PLANT extracts , *ANTIBACTERIAL agents , *CYPERUS , *ZETA potential , *NANOPARTICLES , *METHYLENE blue - Abstract
[Display omitted] • Synthesis of AuNPs utilizing aqueous extract of C. scariosus roots was carried out. • These AuNPs were characterized by UV–Vis, FTIR, SEM, EDX, zeta potential DLS) and PXRD. • The as synthesized AuNPs was evaluated for simple, sensitive and selective colorimetric detection of Ni2+ in aqueous phase. • By using this sensor a wide working range (0–300 µM) and low detection limit (118 nM) was achieved. Nanoparticles (NPs) having diameter in the range of 1–100 nm has been extensively studied for their broad range applications in the field of catalysis, sensing, energy storage and biology. The NPs can be synthesized utilizing multiple approaches, such as sol–gel method, hydrothermal, chemical reduction and green synthesis etc. However, green synthesis utilizing the plant extract as reducing and capping agent has grabbed the special attention due to its eco-friendly, non-hazardous and cost-effective nature. Herein, green synthesis of gold nanoparticles (AuNPs) is being reported utilizing aqueous extract of Cyperus scariosus roots (CSRE) under sunlight irradiation. CSRE@AuNPs have been successfully characterized by UV–Visible and FTIR spectroscopy, Scanning electron microscopy (SEM), Energy-dispersive X-ray spectroscopy (EDX), zeta potential (ZP), dynamic light scattering (DLS) and powder diffraction analysis (PXRD). Average size of the CSRE@AuNPs has been found ∼50 nm. Due to appropriate band gap of CSRE@AuNPs in the range of visible light, these NPs have evaluated for the photocatalytic potential to degrade hazardous organic dye i.e., methylene blue (MB). The NPs were proved to be efficient catalyst by 80% degradation of MB dye in just 90 min exposure to sunlight. These NPs have also been screened for the selective sensing of heavy metal ions in spiked water. CSRE@AuNPs had shown selective colorimetric response for the detection of Ni2+ with limit of detection (LOD) of 118.5 nM and a linear range of 0–300 µM at optimized temperature of 40 °C at wide range of pH (3–9). The zeta potential and hydrodynamic size measurements were carried out to study the effect of Ni2+ on nanoparticle aggregation. A decrease in value of zeta potential from −34.4 to −0.116 mV (ignore the sign) and increase in value of DLS size from 53.2 to 7553 nm of the AuNPs was observed with an increase in concentration of Ni2+ ions from 0 to 300 µM. Furthermore, over 93% recovery and a relative standard deviation (RSD) of roughly 4% proved the effectiveness of this colorimetric nano-probe for Ni2+ detection in untreated natural water samples, such as river and tap water. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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- View/download PDF
242. Tunable dual color emission from the opposite faces of silicon nanoparticle embedded gel-glass.
- Author
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Das, Bhaskar, Hossain, Syed Minhaz, Mohanraj, G.T., Chowdhury, Subhajit Roy, Siddique, Abu Bakar, Rahman, M.R., and Ray, Mallar
- Subjects
- *
NANOPARTICLES , *SILICON , *NANOSILICON , *NANOPARTICLE size , *PHOTOLUMINESCENCE , *PHOTONS - Abstract
A luminescent silicon nanoparticle embedded gel-glass, prepared by room temperature hydrolysis and reduction of aminosilane, exhibits intriguing dual photoluminescence (PL) from opposite faces of the glass. The face, which is excited with UV, exhibits excitation energy dependent blue-green emission. As the excitation energy is varied from 350 nm to 450 nm the PL peaks shift from 435 nm to 506 nm. The opposite surface, on the other hand emits nearly excitation independent green light – the PL peak shifts by ∼17 nm as the excitation energy is varied from 350 nm to 450 nm. The luminescent properties provide interesting insights into the light emission mechanism from nanostructured silicon. Spectral filtering by reabsorption and photon reabsorption-reemission in a size distributed nanoparticle system having different optical gaps play a combined role in the observed dual emission. We show that the dual emission can be tuned by simply varying the thickness of the glass. Such dual emission renders the luminescent glass amenable for several applications as a novel solid state display material. [Display omitted] • A silicon nanocrystal embedded luminescent gel-glass exhibits intriguing dual photoluminescence. • The gel-glass emits different wavelengths from different faces for the same excitation energy. • Dual emission is explained by successive photon reabsorption-reemission and spectral filtering. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
243. O-vacancies induced in co-doped ZnO:(Cu,Fe) synthesized via hydrothermal method by pulsed magnetic field.
- Author
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Tariq, Muhammad, Zaman, Yasir, Shahzad, M., Ahmad, Kamal, Siddique, Abu Bakar, and Zaman, Hira
- Subjects
- *
MAGNETIC fields , *DOPING agents (Chemistry) , *SCANNING electron microscopes , *RAMAN scattering , *X-ray diffraction - Abstract
• O-vacancies induced in co-doped ZnO:(Cu,Fe) by Pulsed magnetic field. • Co-doped NPs synthesized by hydrothermal method. • ZFCO-4T exhibited high performance of RTFM behavior. • Different characterization techniques used such as XRD, SEM, Raman spectroscopy, XPS and VSM. • ZFCO-4T has a higher number of polarons and they overlap excellently. Parent ZnO nanoparticles dually doped (Cu, Fe) were synthesized by the hydrothermal method in the presence of variant pulse magnetic field (PMF) at (0, 4T). X-Ray diffraction (XRD) was used to find crystal structure, Scanning Electron Microscope (SEM) revealed that the transformation of elongated spheres into spheres with increasing magnetic pulse (4T), Raman scattering peaks appeared at 437.70 and 436.63 cm−1 belonged to ZFCO-0T and ZFCO-4T indicated defects and inclusion of dopant elements in parent sample, XPS analysis showed that the decline in compressive strain enhances the contents of vacancies of oxygen (VO) for ZFCO-4T sample, and Bound Magnetic Polarons (BMPs) explained the RTFM order i.e.the sample ZFCO-4T has a higher number of polarons and they overlap excellently. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
244. The tobacco cembranoid (1S,2E,4S,7E,11E)-2,7,11-cembratriene-4,6-diol as a novel angiogenesis inhibitory lead for the control of breast malignancies.
- Author
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Hailat, Mohammad M., Ebrahim, Hassan Y., Mohyeldin, Mohamed M., Goda, Amira A., Siddique, Abu Bakar, and El Sayed, Khalid A.
- Subjects
- *
BREAST cancer treatment , *TOBACCO , *GLYCOLS , *NEOVASCULARIZATION inhibitors , *DITERPENES , *MOLECULAR docking , *THERAPEUTICS - Abstract
(1 S ,2 E ,4 S ,6 R ,7 E ,11 E )-2,7,11-cembratriene-4,6-diol ( 1 ) and its 4- epi -analog ( 2 ) are diterpene precursors of the key flavor components in most Nicotiana (tobacco) species that purposely degraded during commercial tobacco fermentation. Angiogenesis, recruitment of new blood vessels, is important for tumor growth, survival and metastasis that can be targeted to control cancer. This study shows evidences and potential of the cembranoid 1 as a potent angiogenesis modulator through targeting VEGFR 2 . In silico study suggested favorable docking scores and binding affinity of 1 at the ATP binding pocket of VEGFR 2 . The binding mode of 1 was parallel to the standard FDA-approved antiangiogenic drug sunitinib ( 4 ). In vitro, cembranoid 1 significantly reduced the activated VEGFR 2 levels in multiple breast cancer cell lines. Intraperitoneal 40 mg/kg, 3X/week treatment of 1 significantly reduced the MDA-MB-231 cells breast tumor size in mice. Immunohistochemistry and Western blotting analysis of the treated mice tumors showed significant downregulation of the vasculogenesis marker CD31 and suppressed activated VEGFR 2 -paxillin-FAK pathway. Matrigel study in Swiss albino mice showed similar trend. The tobacco cembranoid 1 is a potential antiangiogenic lead useful for future use to control breast malignancies. [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
- View/download PDF
245. Tamed synthesis of AgNPs for photodegradation and anti-bacterial activity: Effect of size and morphology.
- Author
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Zaman, Yasir, Ishaque, Muhammad Zahid, Ajmal, Saira, Shahzad, Muhammad, Siddique, Abu Bakar, Hameed, Muhammad Usman, Kanwal, Humaira, Ramalingam, R. Jothi, Selvaraj, Manickam, and Yasin, Ghulam
- Subjects
- *
ANTIBACTERIAL agents , *FACE centered cubic structure , *ENERGY dispersive X-ray spectroscopy , *X-ray powder diffraction , *SURFACE plasmon resonance , *ORGANIC dyes , *PHOTODEGRADATION , *POLYOLS - Abstract
[Display omitted] • Synthesis of Silver Nanoparticles (AgNPs) was reported utilizing AgNO 3 as precursor and PVP as stabilizing agent in ethylene glycol. • Effect of concentration ratios of AgNO3 and PVP was examined on the morphology and size of AgNPs. • AgNPs were evaluated for their size dependent photocatalytic and antibacterial potential. • Small size AgNPs having high energy band gap exhibited improved photocatalytic potential for degradation of MB dye following pseudo first order kinetics. • AgNPs were found more active against gram-negative strains of bacteria. Organic dyes present in the effluents of paints, and textile industries are posing major environmental threats. Rapid decomposition of these dyes using non-toxic, renewable and cost-effective silver nanoparticles (AgNPs) is a pragmatic strategy. Therefore, in current research work, AgNPs with different size ranges have been prepared following the polyol reduction method by controlled exploitation of substrate/reducing agent molar ratio and pH of reaction media. AgNPs have been characterized by UV–Visible spectroscopy, Scanning Electron Microscope (SEM), Powder X-Ray Diffraction (XRD) and Energy Dispersive X-ray spectroscopy (EDS). Absorption peaks ranging from 420 to 465 nm confirmed the synthesis of AgNPs using surface plasmon resonance (SPR) bands. The increase in molar ratio and pH led to the blue shift in absorption bands which revealed the size reduction of AgNPs. XRD analysis confirmed the crystallite size (16–21 nm) and Face centered cubic (FCC) crystalline structure of AgNPs. EDS was utilized to check the purity of AgNPs. SEM confirmed the spherical morphology of AgNPs with a size range between 70 and 110 nm. The energy band gap was determined using the Tauc plot equation to correlate the catalytic properties of NPs with size. Different-sized AgNPs were utilized as photocatalysts for the degradation of Methylene blue (MB) dye under sunlight irradiation. AgNPs having an average size of 70 nm showed improved photocatalytic potential by 94% degradation of MB in 80 min. The AgNPs were also evaluated for their antibacterial activities against gram-positive and gram-negative strains of bacteria. Small-size AgNPs were found more active against gram-negative strains of bacteria. [ABSTRACT FROM AUTHOR]
- Published
- 2023
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- View/download PDF
246. Sulfonylbis(acylhydrazones) as anticholinesterase inhibitors: Synthesis, in vitro biological evaluation and computational studies.
- Author
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Ibrahim, Muhamad, Latif, Abdul, Ahmad, Manzoor, Ahmad, Sajjad, Ali, Akbar, Siddique, Abu Bakar, Saadiq, Mohammad, Akbar, Nazia, farooq, Umar, Khan, Ajmal, Al-Harrasi, Ahmed, and Ali, Mumtaz
- Subjects
- *
MOLECULAR dynamics , *ACETYLCHOLINESTERASE , *MOLECULAR docking , *INTERMOLECULAR interactions , *GALANTHAMINE , *CHOLINESTERASE inhibitors , *GLYCOSIDASE inhibitors , *CATALYSTS - Abstract
This current research work is focused on the synthesis of sulfonyl-mediated hydrazones, its exploration as anticholinesterase inhibitors, in vitro biological evaluation, and computational studies. A series of 21 novel bis(acylhydrazones) (4a-u) have been synthesized in good to excellent yields using 4,4ꞌ-sulfonyldiphenol as the precursor. Characterization of the synthesized compounds was achieved via spectroscopic techniques i.e. UV, FT-IR, NMR (1H and 13C), and HRMS. In vitro anticholinesterase activity of these compounds was performed using acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) as cholinesterase enzymes. Among all the compounds tested, compounds 4 g and 4 h were found to be the most significant AChE inhibitions with IC 50 values of 101.4 and 102.7 µM as compared to the standard cholinesterase inhibitor i.e., galantamine (IC 50 = 104.5 µM). Additionally, compound 4 g was also found to be an excellent inhibitor of BChE with an IC 50 value of 136.0 µM as compared to the standard galantamine (IC 50 = 156.8 µM). Molecular docking of the most active compounds 4 g and 4 h also supported their potential to interact with cholinesterase enzymes. Further affirmation on the intermolecular stability of the docked complexes was achieved by molecular dynamics simulation for 100 ns with mean deviations ∼2 Å. Residue level fluctuations analysis also interpreted the good stability of compounds interacting pocket residues. Lastly, binding free energy analysis was performed that decipher the intermolecular interactions that are dominated by both van der Waals and electrostatic energies. In short, both theoretical and experimental studies unveiled the compounds as potent blockers of cholinesterase enzymes. • A series of 21 novel bis(acylhydrazones) (4a-u) have been synthesized. • Compounds 4 g and 4 h revealed significant AChE inhibitions. • Compound 4 g was also found to be an excellent inhibitor of BChE. • Molecular docking of 4 g and 4 h supported their potential to interact with enzymes. • Binding free energy analysis deciphers domination of van der Waals and electrostatic energies. [Display omitted] [ABSTRACT FROM AUTHOR]
- Published
- 2022
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- View/download PDF
247. Temperature-dependent heterojunction ternary nanocomposite: Assessing photocatalytic and antibacterial applications.
- Author
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Arif A, Zaman Y, Ishaque MZ, Siddique AB, Zaman H, Shahzad M, and Ali D
- Abstract
Heterojunction nanocomposites (ZnO:NiO:CuO) were synthesized via a hydrothermal method and annealed at three different temperatures (400 °C, 600 °C, and 800 °C). The structural, optical, and electrical properties were examined by employing XRD, SEM, UV-Vis, FTIR, and LCR meter techniques to investigate the effects of annealing. Increasing the annealing temperature resulted in the nanocomposites (NCPs) exhibiting enhanced crystallinity, purity, optical properties, and improved electrical and dielectric behavior. The calculated crystalline sizes (Debye-Scherrer method) of the NCPs were determined to be 21, 26 and 34 nm for annealing temperature 400 °C, 600 °C, and 800 °C, respectively. The calculated bandgaps of synthesized samples were found in the range of 2.92-2.55 eV. This temperature-dependent annealing process notably influenced particle size, morphology, band-gap characteristics, and photocatalytic efficiency. EDX analysis affirmed the sample purity, with elemental peaks of Zn, Cu, Ni, and O. These NCPs demonstrated exceptional photocatalytic activity against various dyes solutions (Methyl orange (MO), Methylene Blue (MB), and mixed solution of dyes) under sunlight and also showed good antibacterial properties assessed by the disc diffusion method. Notably, the nanocomposite annealed at 400 °C exhibited a particularly high degradation efficiency by degrading 96% MB and 91% MO in just 90 min under sunlight., Competing Interests: The authors declare no conflicts of interest., (© 2024 Published by Elsevier Ltd.)
- Published
- 2024
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248. Revisiting plant stress memory: mechanisms and contribution to stress adaptation.
- Author
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Siddique AB, Parveen S, Rahman MZ, and Rahman J
- Abstract
Highly repetitive adverse environmental conditions are encountered by plants multiple times during their lifecycle. These repetitive encounters with stresses provide plants an opportunity to remember and recall the experiences of past stress-associated responses, resulting in better adaptation towards those stresses. In general, this phenomenon is known as plant stress memory. According to our current understanding, epigenetic mechanisms play a major role in plants stress memory through DNA methylation, histone, and chromatin remodeling, and modulating non-coding RNAs. In addition, transcriptional, hormonal, and metabolic-based regulations of stress memory establishment also exist for various biotic and abiotic stresses. Plant memory can also be generated by priming the plants using various stressors that improve plants' tolerance towards unfavorable conditions. Additionally, the application of priming agents has been demonstrated to successfully establish stress memory. However, the interconnection of all aspects of the underlying mechanisms of plant stress memory is not yet fully understood, which limits their proper utilization to improve the stress adaptations in plants. This review summarizes the recent understanding of plant stress memory and its potential applications in improving plant tolerance towards biotic and abiotic stresses., Competing Interests: Conflict of interestAll the authors declare no conflicts of interest regarding this study., (© Prof. H.S. Srivastava Foundation for Science and Society 2024. Springer Nature or its licensor (e.g. a society or other partner) holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law.)
- Published
- 2024
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249. Hydro-chemical characteristics and groundwater quality evaluation in south-western region of Bangladesh: A GIS-based approach and multivariate analyses.
- Author
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Hossain MS, Nahar N, Shaibur MR, Bhuiyan MT, Siddique AB, Al Maruf A, and Khan AS
- Abstract
The study focuses on the chemistry of groundwater and if it is suitable for drinking and for use in agriculture using water quality indices, GIS mapping, and multivariate analyses in Sharsa Upazila, Jashore district, Bangladesh. In this study, the concentration of NH
4 + , K+ , Ca2+ , EC, Turbidity overstep BDWS drinking standards in 69 %, 14 %, 100 %, 40 % (WHO), 73 % of samples respectively. The value of Water Quality Indices (WQI) results inferred that the maximum specimen was held good quality for drinking uses, and the values distributed central eastern part to the south-eastern part were good quality water in the selected studied area. The study area's PH, EC, SAR, Na (%), TH, and NO3- values were mapped using GIS tools to show their spatial distribution. The cluster and correlation matrix analyses are used to validate for Principle Component Analysis (PCA). The five PCA results exhibited that the presence of EC, turbidity, K+ , SO4 2- and NO3- was significant and was caused by both geogenic (rock weathering and cation exchange) and anthropogenic (agrochemicals, animal feedback) factor. According to the hydro-geochemical data, the maximum number of samples is of the Ca-Mg-HCO3-Cl type and is dominated by rocks. The irrigation water indices like MH, KR, SAR, and %Na indicate show high-quality groundwater for irrigation purposes. Most of the samples were satisfactory and compiled with WHO and Bangladeshi criteria for standard drinking water guideline values., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2024 The Authors.)- Published
- 2024
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250. Synthesis of hydroxyethylcellulose phthalate-modified silver nanoparticles and their multifunctional applications as an efficient antibacterial, photocatalytic and mercury-selective sensing agent.
- Author
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Siddique AB, Amr D, Abbas A, Zohra L, Irfan MI, Alhoshani A, Ashraf S, and Amin HMA
- Subjects
- Silver chemistry, Escherichia coli, Staphylococcus aureus, Anti-Bacterial Agents chemistry, Coloring Agents chemistry, Water, Ions, Plant Extracts chemistry, Mercury, Metal Nanoparticles chemistry, Cellulose analogs & derivatives, Phthalic Acids
- Abstract
Water contamination by several aquatic pollutants such as dyes, heavy metal ions and microbes is a prevalent concern to health and environment. Thus, developing facile, economical, and eco-friendly strategies to tackle this problem have become paramount. Hence, this study reports the synthesis of hydroxyethylcellulose phthalate-capped silver nanoparticles (HEC-PA@AgNPs) using a simple sunlight-assisted route. The multifunctional applications of the synthesized particles as an efficient nanoprobe for the selective sensing of Hg
2+ as well as their photocatalytic and antimicrobial activities were demonstrated. HEC-PA@AgNPs were systematically characterized by various advanced analytical techniques such as FTIR, UV-Vis spectroscopy, X-ray diffraction (XRD), zeta potential (ZP) and dynamic light scattering (DLS). The successful functionalization of AgNPs with HEC-PA was manifested using FTIR. SEM and XRD revealed the formation of spherical AgNPs with a face centered cubic structure and a crystallite size of 14 nm. The particles demonstrated a hydrodynamic size of 40 nm with a good colloidal stability as evidenced from the ZP value of -35 mV, suggesting the effective role of the negatively charged HEC-PA capping agent in stabilizing the NPs. HEC-PA@AgNPs exhibited fast naked-eye colorimetric detection, high selectivity, and sensitivity to Hg2+ in spiked real water samples over a wide range of pH (3-9) and temperatures (298-328 K), achieving a detection limit of 119 nM. The presence of other diverse metal ions didn't affect the specificity of the particles toward Hg ions. Further, the sensing mechanism is based on a characteristic redox reaction between Hg2+ and AgNPs. Further, HEC-PA@AgNPs showcased a more noxious antimicrobial activity to gram-positive bacteria (B. subtilis and S. aureus) than gram-negative bacteria (E. coli). Besides, AgNPs exhibited high photocatalytic potential under sunlight irradiation with a degradation efficiency of 79 % for methylene blue dye in only 80 min following pseudo-1st order kinetics with a rate constant of 0.019 min-1 . The photocatalyst exhibited good reusability after five recycling runs. These results render our approach promising multifunctional analytical probe for environmental and biomedical applications., Competing Interests: Declaration of competing interest The authors declare no conflict of interest., (Copyright © 2023 Elsevier B.V. All rights reserved.)- Published
- 2024
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