Publications by authors named "Wasim Ullah Khan"

16 Publications

  • Page 1 of 1

Design of Nonlinear Autoregressive Exogenous Model Based Intelligence Computing for Efficient State Estimation of Underwater Passive Target.

Entropy (Basel) 2021 Apr 29;23(5). Epub 2021 Apr 29.

School of Marine Science and Technology, Northwestern Polytechnical University, Xi'an 710072, China.

In this study, an intelligent computing paradigm built on a nonlinear autoregressive exogenous (NARX) feedback neural network model with the strength of deep learning is presented for accurate state estimation of an underwater passive target. In underwater scenarios, real-time motion parameters of passive objects are usually extracted with nonlinear filtering techniques. In filtering algorithms, nonlinear passive measurements are associated with linear kinetics of the target, governing by state space methodology. To improve tracking accuracy, effective feature estimation and minimizing position error of dynamic passive objects, the strength of NARX based supervised learning is exploited. Dynamic artificial neural networks, which contain tapped delay lines, are suitable for predicting the future state of the underwater passive object. Neural networks-based intelligence computing is effectively applied for estimating the real-time actual state of a passive moving object, which follows a semi-curved path. Performance analysis of NARX based neural networks is evaluated for six different scenarios of standard deviation of white Gaussian measurement noise by following bearings only tracking phenomena. Root mean square error between estimated and real position of the passive target in rectangular coordinates is computed for evaluating the worth of the proposed NARX feedback neural network scheme. The Monte Carlo simulations are conducted and the results certify the capability of the intelligence computing over conventional nonlinear filtering algorithms such as spherical radial cubature Kalman filter and unscented Kalman filter for given state estimation model.
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http://dx.doi.org/10.3390/e23050550DOI Listing
April 2021

Petri Net based modeling and analysis for improved resource utilization in cloud computing.

PeerJ Comput Sci 2021 8;7:e351. Epub 2021 Feb 8.

School of Electrical Engineering and Automation, Wuhan University, Wuhan, China.

The cloud is a shared pool of systems that provides multiple resources through the Internet, users can access a lot of computing power using their computer. However, with the strong migration rate of multiple applications towards the cloud, more disks and servers are required to store huge data. Most of the cloud storage service providers are replicating full copies of data over multiple data centers to ensure data availability. Further, the replication is not only a costly process but also a wastage of energy resources. Furthermore, erasure codes reduce the storage cost by splitting data in chunks and storing these chunks into different data centers, to tolerate failures. Moreover, it also needs extra computation cost to regenerate the data object. Cache-A Replica On Modification (CAROM) is a hybrid file system that gets combined benefits from both the replication and erasure codes to reduce access latency and bandwidth consumption. However, in the literature, no formal analysis of CAROM is available which can validate its performance. To address this issue, this research firstly presents a colored Petri net based formal model of CAROM. The research proceeds by presenting a formal analysis and simulation to validate the performance of the proposed system. This paper contributes towards the utilization of resources in clouds by presenting a comprehensive formal analysis of CAROM.
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http://dx.doi.org/10.7717/peerj-cs.351DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7959626PMC
February 2021

Size-activity threshold of titanium dioxide-supported Cu cluster in CO oxidation.

Environ Pollut 2021 Jun 10;279:116899. Epub 2021 Mar 10.

Department of Chemical and Process Engineering, University of Canterbury, Christchurch, 8140, New Zealand.

Development of non-noble metal cluster catalysts, aiming at concurrently high activity and stability, for emission control systems has been challenging because of sintering and overcoating of clusters on the support. In this work, we reported the role of well-dispersed copper nanoclusters supported on TiO in CO oxidation under industrially relevant operating conditions. The catalyst containing 0.15 wt% Cu on TiO (0.15 CT) exhibited a high dispersion (59.1%), a large specific surface area (381 m/g), a small particle size (1.77 nm), and abundant active sites (75.8% CuO). The CO oxidation activity measured by the turnover frequency (TOF) was found to be enhanced from 0.60 × 10 to 3.22 × 10 mol·mol·s as the copper loading decreased from 5 to 0.15 wt%. A CO conversion of approximately 60% was still observed in the supported cluster catalyst with a Cu loading of 5 wt% at 240 °C. No deactivation was observed for catalysts with low copper loading (0.15 and 0.30 CT) after 8 h of time-on-stream, which compares favorably with less stable Au cluster-based catalysts reported in the literature. In contrast, catalysts with high copper loading (0.75 and 5 CT) showed deactivation over time, which was ascribed to the increase in copper particle size due to metal cluster agglomeration. This study elucidated the size-activity threshold of TiO-supported Cu cluster catalysts. It also demonstrated the potential of the supported Cu cluster catalyst at a typical temperature range of diesel engines at light-load. The supported Cu cluster catalyst could be a promising alternative to noble metal cluster catalysts for emission control systems.
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http://dx.doi.org/10.1016/j.envpol.2021.116899DOI Listing
June 2021

Antimicrobial and antioxidant chlorinated azaphilones from mangrove sp. isolated from the stem of Chinese mangrove .

J Asian Nat Prod Res 2020 Nov 3:1-8. Epub 2020 Nov 3.

School of Marine Sciences, Sun Yat-sen University, Guangzhou 510006, China.

Many plants remain unexplored for their endophytic fungi that may possess potentially important phytochemicals. Consequently, we have focused to discover new natural products from endophytic fungus sp. isolated from the stem of the Chinese mangrove Pierre plant that led to the isolation of one new chlorinated () along with six known azaphilones (). The structures of the isolated compounds were elucidated by UV, NMR and Mass spectroscopic analysis. All the isolated compounds were screened for their antimicrobial and anti-oxidant activities.
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http://dx.doi.org/10.1080/10286020.2020.1835872DOI Listing
November 2020

Eu , Sm Deep-Red Phosphors as Novel Materials for White Light-Emitting Diodes and Simultaneous Performance Enhancement of Organic-Inorganic Perovskite Solar Cells.

Small 2020 Jun 27;16(25):e2001551. Epub 2020 May 27.

Department of Chemistry, King Fahd University of Petroleum & Minerals, Dhahran, 31261, Saudi Arabia.

The luminous efficiency of inorganic white light-emitting diodes, to be used by the next generation as light initiators, is continuously progressing and is an emerging interest for researchers. However, low color-rendering index (Ra), high correlated color temperature (CCT), and poor stability limit its wider application. Herein, it is reported that Sm - and Eu -doped calcium scandate (CaSc O (CSO)) are an emerging deep-red-emitting material with promising light absorption, enhanced emission properties, and excellent thermal stability that make it a promising candidate with potential applications in emission display, solid-state white lighting, and the device performance of perovskite solar cells (PSCs). The average crystal structures of Sm -doped CSO are studied by synchrotron X-ray data that correspond to an extremely rigid host structure. Samarium ion is incorporated as a sensitizer that enhances the emission intensity up to 30%, with a high color purity of 88.9% with a 6% increment. The impacts of hosting the sensitizer are studied by quantifying the lifetime curves. The CaSc O :0.15Eu ,0.03Sm phosphor offers significant resistance to thermal quenching. The incorporation of lanthanide ion-doped phosphors CSOE into PSCs is investigated along with their potential applications. The CSOE-coated PSCs devices exhibit a high current density and a high power conversion efficiency (15.96%) when compared to the uncoated control devices.
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http://dx.doi.org/10.1002/smll.202001551DOI Listing
June 2020

pharmacological investigation of and using animal models.

Saudi J Biol Sci 2019 Nov 9;26(7):1602-1606. Epub 2018 Oct 9.

Department of Biological Sciences Gomal University Dera Ismail Khan KP, Pakistan.

Experimental based evidence suggests that most of the medicinal plants possess wide-ranging pharmacological and biological activities that may possibly use in treatment of inflammation-related diseases. The current study was aimed to explore the acute toxicity, analgesic, sedative and antipyretic activities of and in mices. In experimental models were used in this study. Acute toxicity was evaluated for 24 h' interval at concentration of 500, 1000, 1500 and 2000 mg/kg. The analgesic activity was estimated by acetic acid induced writhing test. White wood apparatus enclosed in stainless steel was used for sedative experiment and antipyretic activity was evaluated in brewer's yeast induced hyperthermic at 50, 100 and 150 mg/kg i.p. Both plants were found safe at all tested doses. and dose-dependently reduced abdominal constrictions in mice. Both plants exhibited significant ( < 0.0001) sedative effects in dose of 50, 150 and 150 mg/kg. Both plants markedly ( < 0.0001) reduced yeast induced hyperthermia. The inhibitions were dose-dependent and remained significant up to five hours of administration. These investigational results have linked a pharmacological indication for the traditional claim of the drugs to be used as an anti-inflammatory, analgesics and antipyretic agents.
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http://dx.doi.org/10.1016/j.sjbs.2018.10.008DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6864368PMC
November 2019

Antagonist effects of strains of Bacillus spp. against Rhizoctonia solani for their protection against several plant diseases: Alternatives to chemical pesticides.

C R Biol 2019 Jun - Aug;342(5-6):124-135. Epub 2019 Aug 9.

Statistical Genomics Lab, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan 430070, China.

Rhizoctonia solan Kühn (teleomorph: Thanatephorus cucumeris (Frank) Donk (R. solani) is a soil-borne phytopathogenic species complex as well as a necrotic fungus that causes significant crop yield losses worldwide. Agronomic practices (crop rotation), resistant cultivars, and chemical pesticides are widely used to control R. solani. However, these practices are insufficient to control the pest. Moreover, the application of chemical pesticides is harmful to both the environment and human health. Therefore, the use of biocontrol agents (BCAs) and that of plant-growth promoting bacteria (PGPB) are considered to be potentially sustainable, cost-effective, efficient, and eco-friendly ways to control R. solani. Several microorganisms have been used as biocontrol agents (BCAs) to manage R. solani. Among these, biocontrol agents (BCAs) Bacillus spp. are used to promote plant growth. Furthermore, due to its broad range of antibiotic-producing abilities, Bacillus spp. is widely used against R. solani. In this review, current and previous studies about the ability of Bacillus spp. to control diseases caused by R. solani are reported. It also focuses on the plant-growth promotion attributes of Bacillus spp. in response to the deleterious effects of R. solani.
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http://dx.doi.org/10.1016/j.crvi.2019.05.002DOI Listing
December 2019

Fusion of conjugated bicyclic co-polymer within polymeric carbon nitride for high photocatalytic performance.

J Colloid Interface Sci 2019 Oct 18;554:627-639. Epub 2019 Jul 18.

School of Chemistry, Sun Yat-Sen University, Guangzhou 510275, PR China.

The intertwined exploring of solar water driven into chemical energy configurated by a constituted semiconductor photocatalyst under sunlight approach toward a remediation eager method that solve the environmental issues. Currently we optimized polymeric carbon nitride PCN by a sophisticated molecular co-polymerization process which diffused with a mirror organic conjugated heterocyclic monomer to maximize its photocatalytic activity. Herein, for the 1st time we report an organic π-electron stacking conjugated thiazolothiazole (TT) as a small molecule within the framework of PCN to enhance the conductive optical and photocatalytic properties of PCN under solar energy irradiation. The fusion of this bicyclic thiazolothiazole (TT) co-monomer within PCN remarkably enhanced the charge carrier motilities and giving a rigid packing due to sulfur contents. Excitingly the as-synthesized samples were processed under different liberated characterization such as XRD, FTIR, BET, SEM, TEM, XPS, PL, DRS and EPR under both regions respectively. Results reflect that the integration of thiazolothiazole (TT) in the heptazine structure of PCN alter a prodigious delocalization in its π-conjugated system and similarly demonstrating an apparent fluctuation in its surface area, electronic structure, its calculated band gap, chemical composition analysis and maximize the process of generation of electrons under solar light from ground state (HOMO) to the excited state (LUMO) of polymeric carbon nitride (PCN). Beside, this unique integrity of TT co-monomer with in PCN matrix remarkably improve the photocatalytic activity toward prosperity and the amount optimized CNU-TT demonstrated an outstanding photocatalytic activity of water reduction for H evolution and as well of RhB pollutant photodegradation. The sample optimized display 10.6 enhancement comparatively pure pristine sample.
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http://dx.doi.org/10.1016/j.jcis.2019.07.048DOI Listing
October 2019

Synthesis and optimization of the trimesic acid modified polymeric carbon nitride for enhanced photocatalytic reduction of CO.

J Colloid Interface Sci 2019 Jul 13;548:197-205. Epub 2019 Apr 13.

School of Chemistry, Sun Yat-Sen University, Guangzhou 510275, PR China. Electronic address:

The conjugated co-monomer, trimesic acid (TMA) was integrated into the triazine framework of polymeric carbon nitride (PCN), synthesized through chemical condensation of urea. The TMA-modified carbon nitride samples obtained were named as CNU-TMA and it was utilized for the photocatalytic reduction of carbon dioxide (CO) under visible light illumination. The induction of such electron donor-acceptor co-monomer (TMA) dominates the intramolecular structure of PCN by acting as a nucleophilic substitution substrate to facilitate the electron density in the π-electron conjugated system of PCN and thus elevate its photocatalytic activity. Also, this process of copolymerization with TMA, not only cause a significant diversion in the specific area, band gap, chemical composition, and structure of PCN but also promote efficient charge transport from ground state (HOMO) to the excited state (LUMO) of the PCN. For comparison, CNU samples modified with other co-monomers were prepared by the same method and were named as CNU-FDA (2,5-Furandicarboxylic acid), CNU-PDA (2,6-pyridinedicarboxylic acid), CNU-PTA (Phthalic acid). Similarly, co-monomer TMA was incorporated in other PCN precursors such as dyandicyanamide (DCDA), thiourea (SCN) and ammonium thiocyanate (NHSCN) and was named as CND-TMA, CNT-TMA, and CNA-TMA, respectively. Besides, the average weight ratio between urea and TMA was well tuned and also CNU-TMA gain a fabulous 16 fold-enhanced photocatalytic performance than blank CNU.
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http://dx.doi.org/10.1016/j.jcis.2019.04.037DOI Listing
July 2019

Nano-biotechnology: a new approach to treat and prevent malaria.

Int J Nanomedicine 2019 21;14:1401-1410. Epub 2019 Feb 21.

Institute of Chemical Sciences, Gomal University, Dera Ismail Khan, Pakistan.

Malaria, the exterminator of ~1.5 to 2.7 million human lives yearly, is a notorious disease known throughout the world. The eradication of this disease is difficult and a challenge to scientists. Vector elimination and effective chemotherapy for the patients are key tactics to be used in the fight against malaria. However, drug resistance and environmental and social concerns are the main hurdles in this fight against malaria. Overcoming these limitations is the major challenge for the 21st-century malarial researchers. Adapting the principles of nano-biotechnology to both vector control and patient therapy is the only solution to the problem. Several compounds such as lipids, proteins, nucleic acid and metallic nanoparticles (NPs) have been successfully used for the control of this lethal malaria disease. Other useful natural reagents such as microbes and their products, carbohydrates, vitamins, plant extracts and biodegradable polymers, are also used to control this disease. Among these particles, the plant-based particles such as leaf, root, stem, latex, and seed give the best antagonistic response against malaria. In the present review, we describe certain efforts related to the control, prevention and treatment of malaria. We hope that this review will open new doors for malarial research.
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http://dx.doi.org/10.2147/IJN.S190692DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6390872PMC
April 2019

In vitro biological screening of a critically endangered medicinal plant, Atropa acuminata Royle Ex Lindl of north western Himalaya.

Sci Rep 2018 07 23;8(1):11028. Epub 2018 Jul 23.

Department of Agriculture, University of Swabi, Swabi, Khyber Pakhtunkhwa, Pakistan.

Atropa acuminata Royle Ex Lindl (Atropa acuminata) under tremendous threat of extinction in its natural habitat. However, the antimicrobial, antileishmanial and anticancer effects of the plant's extracts have not been reported yet. In the current study, an attempt has been made to evaluate the pharmacological potential of this plant's extracts against microbes, Leishmania and cancer. The roots, stems and leaves of Atropa acuminata were ground; then, seven different solvents were used alone and in different ratios to prepare crude extracts, which were screened for pharmacological effects. The aqueous, methanolic and ethanolic extracts of all parts carried a broad spectrum of anti-bacterial activities, while no significant activity was observed with combined solvents. Three types of cytotoxicity assays were performed, i.e., haemolytic, brine shrimp and protein kinase assays. The aqueous extract of all the parts showed significant haemolytic activity while n-hexane extracts of roots showed significant activity against brine shrimp. The acetone extracts strongly inhibited protein kinase while the methanolic extracts exhibited significant cytotoxic activity of roots and stem. The anti-leishmanial assays revealed that the methanolic extract of leaves and roots showed significant activity. These findings suggest that this plant could be a potential source of natural product based drugs.
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http://dx.doi.org/10.1038/s41598-018-29231-xDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6056422PMC
July 2018

Honey: Single food stuff comprises many drugs.

Saudi J Biol Sci 2018 Feb 16;25(2):320-325. Epub 2017 Aug 16.

Department of Biotechnology, Quaid-i-Azam University, Islamabad, Pakistan.

Honey is a natural food item produced by honey bees. Ancient civilizations considered honey as a God gifted prestigious product. Therefore, a huge literature is available regarding honey importance in almost all religions. Physically, honey is a viscous and jelly material having no specific color. Chemically, honey is a complex blend of many organic and inorganic compounds such as sugars, proteins, organic acids, pigments, minerals, and many other elements. Honey use as a therapeutic agent is as old as human civilization itself. Prior to the appearance of present day drugs, honey was conventionally used for treating many diseases. At this instant, the modern research has proven the medicinal importance of honey. It has broad spectrum anti-biotic, anti-viral and anti-fungal activities. Honey prevents and kills microbes through different mechanism such as elevated pH and enzyme activities. Till now, no synthetic compound that works as anti-bacterial, anti-viral and anti-fungal drugs has been reported in honey yet it works against bacteria, viruses and fungi while no anti-protozoal activity has been reported. Potent anti-oxidant, anti-inflammatory and anti-cancerous activities of honey have been reported. Honey is not only significant as anti-inflammatory drug that relieve inflammation but also protect liver by degenerative effects of synthetic anti-inflammatory drugs. This article reviews physico-chemical properties, traditional use of honey as medicine and mechanism of action of honey in the light of modern scientific medicinal knowledge.
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http://dx.doi.org/10.1016/j.sjbs.2017.08.004DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5815988PMC
February 2018

Nanosilver: new ageless and versatile biomedical therapeutic scaffold.

Int J Nanomedicine 2018 2;13:733-762. Epub 2018 Feb 2.

College of Plant Sciences and Technology.

Silver nanotechnology has received tremendous attention in recent years, owing to its wide range of applications in various fields and its intrinsic therapeutic properties. In this review, an attempt is made to critically evaluate the chemical, physical, and biological synthesis of silver nanoparticles (AgNPs) as well as their efficacy in the field of theranostics including microbiology and parasitology. Moreover, an outlook is also provided regarding the performance of AgNPs against different biological systems such as bacteria, fungi, viruses, and parasites (leishmanial and malarial parasites) in curing certain fatal human diseases, with a special focus on cancer. The mechanism of action of AgNPs in different biological systems still remains enigmatic. Here, due to limited available literature, we only focused on AgNPs mechanism in biological systems including human (wound healing and apoptosis), bacteria, and viruses which may open new windows for future research to ensure the versatile application of AgNPs in cosmetics, electronics, and medical fields.
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http://dx.doi.org/10.2147/IJN.S153167DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5799856PMC
April 2018

Efficient energy transfer and luminescence properties of CaY(GaO)(BO):Tb,Eu as a green-to-red colour tunable phosphor under near-UV excitation.

Dalton Trans 2017 Feb;46(6):1885-1891

Key Laboratory of Bioinorganic and Synthetic Chemistry of Ministry of Education, School of Chemistry, Sun Yat-Sen University, Guangzhou 510275, P. R. China.

A series of CaY(GaO)(BO):Tb,Eu phosphors were prepared by a high-temperature solid-state reaction. Their phase structures were confirmed by powder X-ray diffraction and the element distribution was measured using transmission electron microscopy elemental mapping. The photoluminescence emission and excitation spectra and fluorescence lifetime were studied and discussed in detail. The results revealed that Eu ions can be efficiently sensitized by Tb ions under near-UV excitation. In addition, the energy transfer efficiency can be controlled by adjusting the ratio of Eu and Tb to realize colour tunable emission from green to red. For CaY(GaO)(BO):0.50Tb,0.10Eu, the emission intensity at 425 K is 78.11% of that at 300 K, being available to near-UV LEDs.
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http://dx.doi.org/10.1039/c6dt04304fDOI Listing
February 2017