Chemical diversity of essential oils from flowers,leaves,and stems of Rhanterium epapposum Oliv. growing in northern border region of Saudi Arabia

Objective:To evaluate the medicinal uses of Rhanterium epapposum Oliv.(R.epapposum) growing in northern border region of Saudi Arabia,through the chemical diversity of essential oils extracted from its flowers,leaves and stems.Methods:Aerial parts of R.epapposum were collected in April 2014.Air dried flowers,leaves,and stems were separately subjected to hydrodistillation in a Clevenger-type apparatus for 4 h to extract the essential oils.Gas chromatography-mass spectrometry analysis of the essential oils was carried out using an Agilent 6890 gas chromatograph equipped with an Agilent 5973 mass spectrometric detector.Results:A total of 51 compounds representing 76.35%–94.86% of flowers,leaves and stems oils composition were identified.The chemical profiles of the studied fractions revealed the dominance of monoterpenes,regardless of qualitative and quantitative differences observed.Limonene,linalool,4-terpineol and a-cadinol represented the major constituents of flowers oil.Leaves oil was dominated by limonene,sabinene,a-pinene and b-myrcene whereas linalool,ionole,a-cadinol,b-eudesmol,4-terpineol,and aterpineol were the major constituents of stems oil.Conclusions:Essential oils from flowers,leaves and stems of R.epapposum growing in northern border region of Saudi Arabia are considered as a rich source of monoterpenes which have biological activities.

MXene@c-MWCNT Adhesive Silica Nanofiber Membranes Enhancing Electromagnetic Interference Shielding and Thermal Insulation Performance in Extreme Environments

A lightweight flexible thermally stable composite is fabricated by com-bining silica nanofiber membranes(SNM)with MXene@c-MWCNT hybrid film.The flexible SNM with outstanding thermal insulation are prepared from tetraethyl orthosilicate hydrolysis and condensation by electrospinning and high-temperature calcination;the MXene@c-MWCNT_(x:y)films are prepared by vacuum filtration tech-nology.In particular,the SNM and MXene@c-MWCNT_(6:4)as one unit layer(SMC_(1))are bonded together with 5 wt%polyvinyl alcohol(PVA)solution,which exhibits low thermal conductivity(0.066 W m^(-1)K^(-1))and good electromagnetic interference(EMI)shielding performance(average EMI SE_(T),37.8 dB).With the increase in func-tional unit layer,the overall thermal insulation performance of the whole composite film(SMC_(x))remains stable,and EMI shielding performance is greatly improved,especially for SMC_(3)with three unit layers,the average EMI SET is as high as 55.4 dB.In addition,the organic combination of rigid SNM and tough MXene@c-MWCNT_(6:4)makes SMC_(x)exhibit good mechanical tensile strength.Importantly,SMC_(x)exhibit stable EMI shielding and excellent thermal insulation even in extreme heat and cold environment.Therefore,this work provides a novel design idea and important reference value for EMI shielding and thermal insulation components used in extreme environmental protection equipment in the future.

Dietary Habits and Oral Hygiene Practice amongst Dental Students at the College of Dentistry, Princess Nourah University

The aim of the present study was to assess the dietary habits and oral hygiene practice of dental students in a new dental school. A self-administered structured closed-ended questionnaire on demographic characteristics, medical history, oral hygiene and dietary habits was distributed to dental students. Results showed that One third of students indicated that they don’t consume low pH beverages (soft drinks) at all, while 48.9% drink a soft drink or two a day. Students took varying amount of time to consume their drinks. The majority of participants consumed citric juices, fruits and/or pickles at least once a day. 91.3% of students use either soft (41.8%) or medium (49.5%) toothbrush. Only a fifth (16.9%) of the students brush their teeth after drinking soft drinks and 58.2% brush their teeth after vomiting. In conclusion, young adults need to be aware about their dietary habits & oral hygiene, and also a proper dental health program needs to be applied.

Sea Turtle Foraging Optimization-Based Controller Placement with Blockchain-Assisted Intrusion Detection in Software-Defined Networks

Software-defined networking(SDN)algorithms are gaining increas-ing interest and are making networks flexible and agile.The basic idea of SDN is to move the control planes to more than one server’s named controllers and limit the data planes to numerous sending network components,enabling flexible and dynamic network management.A distinctive characteristic of SDN is that it can logically centralize the control plane by utilizing many physical controllers.The deployment of the controller—that is,the controller placement problem(CPP)—becomes a vital model challenge.Through the advancements of blockchain technology,data integrity between nodes can be enhanced with no requirement for a trusted third party.Using the lat-est developments in blockchain technology,this article designs a novel sea turtle foraging optimization algorithm for the controller placement problem(STFOA-CPP)with blockchain-based intrusion detection in an SDN environ-ment.The major intention of the STFOA-CPP technique is the maximization of lifetime,network connectivity,and load balancing with the minimization of latency.In addition,the STFOA-CPP technique is based on the sea turtles’food-searching characteristics of tracking the odour path of dimethyl sulphide(DMS)released from food sources.Moreover,the presented STFOA-CPP technique can adapt with the controller’s count mandated and the shift to controller mapping to variable network traffic.Finally,the blockchain can inspect the data integrity,determine significantly malicious input,and improve the robust nature of developing a trust relationship between sev-eral nodes in the SDN.To demonstrate the improved performance of the STFOA-CPP algorithm,a wide-ranging experimental analysis was carried out.The extensive comparison study highlighted the improved outcomes of the STFOA-CPP technique over other recent approaches.

Flow and heat transfer of a nanofluid through a porous medium due to stretching/shrinking sheet with suction,magnetic field and thermal radiation

This study investigates the suction and magnetic field effects on the two-dimensional nanofluid flow through a stretching/shrinking sheet at the stagnation point in the porous medium with thermal radiation.The governing partial differential equations(PDEs)are converted into ordinary differential equations(ODEs)using the similarity transformation.The resulting ODEs are then solved numerically by using the bvp4c solver in MATLAB software.It was found that dual solutions exist for the shrinking parameter values up to a certain range.The numerical results obtained are compared,and the comparison showed a good agreement with the existing results in the literature.The governing parameters’effect on the velocity,temperature and nanoparticle fraction fields as well as the skin friction coefficient,the local Nusselt number and the Sherwood number are represented graphically and analyzed.The variation of the velocity,temperature and concentration increase with the increase in the suction and magnetic field parameters.It seems that the thermal radiation effect has increased the local Sherwood number while the local Nusselt number is reduced with it.

Numerical Treatment of MHD Flow of Casson Nanofluid via Convectively Heated Non-Linear Extending Surface with Viscous Dissipation and Suction/Injection Effects

This paper introduces the effect of heat absorption(generation)and suction(injection)on magnetohydrodynamic(MHD)boundary-layer flow of Casson nanofluid(CNF)via a non-linear stretching surface with the viscous dissipation in two dimensions.By utilizing the similarity transformations,the leading PDEs are transformed into a set of ODEs with adequate boundary conditions and then resolved numerically by(4–5)^(th)-order Runge-Kutta Fehlberg procedure based on the shooting technique.Numerical computations are carried out by Maple 15 software.With the support of graphs,the impact of dimensionless control parameters on the nanoparticle concentration profiles,the temperature,and the flow velocity are studied.Other parameters of interest,such as the skin friction coefficient,heat,and mass transport at the diverse situation and dependency of various parameters are inspected through tables and graphs.Additionally,it is verified that the numerical computations with the reported earlier studies are in an excellent approval.It is found that the heat and mass transmit rates are enhanced with the increasing values of the power-index and the suction(blowing)parameter,whilst are reduced with the boosting Casson and the heat absorption(generation)parameters.Also,the drag force coefficient is an increasing function of the powerindex and a reduction function of Casson parameter.

Two new bioactive salsolanol and biphenylsalsinol from the aerial parts of Salsola villosa Delile. ex Schul.(Chenopodiaceae) growing in Saudi Arabia

Objective: To isolate and characterize the bioactive secondary metabolites from aerial parts of widespread Chenopodiaceae taxa growing in Saudi Arabia: Salsola villosa Delile. ex Schul. Methods: Antibacterial activities of chloroformic extract, fractions and isolate compounds was evaluated against five bacterial strains(Escherichia coli, Pseudomonas aeruginosa, Salmonella typhimurium, Staphylococcus aureus and Staphylococcus epidermidis), using a paper disc diffusion method. The purification of compound(s) of chloroform extract was done by chromatographic column of silica gel. The structure elucidation was determined by extensive spectroscopic analysis(1H and 13 C nuclear magnetic resonance, correlation spectroscopy, heteronuclear multiple bond correlation, heteronuclear multiple quantum coherence and nuclear overhauser enhancement spectroscopy) and high resolution electrospray ionization mass spectroscopy analysis.Results: Bioactivity guided fractionation of the chloroformic extract led to the isolation of two bioactive compounds: 4-(4'-hydroxy-2'-methylcyclopent-2'-enyloxy)-4-methylcyclopent-2-enol(1) named salsolanol and 4'-[3-(hydroxymethyl)oxiran-2-yl]-3-[(E)-3-hydroxyprop-1-en-1-yl]-6, 2'-dimethoxy [1, 1'-biphenyl]-2-ol(2) named biphenylsalsinol. The antibacterial effects of the chloroform extracts, fractions and isolated compounds 1 and 2 were also evaluated in this work. Results showed that the compounds 1 and 2 exhibited antibacterial activities against four strains: Staphylococcus aureus, Staphylococcus epidermidis, Escherichia coli and Pseudomonas aeruginosa with diameter of zone of inhibition ranging between(9.33 ± 0.94) to(26.33 ± 0.94) mm.Conclusions: Based on data presented here, two new natural compounds secondary cyclic alcohol 1 and biphenylpropanoid 2 isolated from bioactive chloroformic extract from aerial parts of Salsola villosa can be responsible for its antibacterial activities.

Synthesis of Novel 4-Thiazolidinone and Bis-Thiazalidin-4-One Derivatives Derived from 4-Amino-Antipyrine and Evaluated as Inhibition of Purine Metabolism Enzymes by Bacteria

Novel 4-thiazolidione and 1,4-bis-thiazolidinone derivatives bearing antipyrine moiety have been obtained from condensation of 4-aminoantipyrine 1 with aromatic/heteroaldehydes followed by cycloaddition with mercaptoacetic acid in nonpolar solvents. Structure of the products has been deduced upon their elemental analysis and spectral measurements. Most of the targets evaluated as enzymatic effect towards some bacteria (E. coli) in compare with Xanthine oxidase (from buttermilk) where the role of compounds is an inhibition of purine metabolism enzymes caused by E. coli.

The Influence of Cu on the Dielectric Properties of NiZnFe₂O₄Synthesized by Solid State Reaction Method

The phase pure Copper Ferrite, Zinc Ferrite, and Nickel Ferrite were prepared from oxides of Ni, Cu, Zn, and Fe using traditional ceramic method. X-ray diffraction data were collected and the formation of the spinal phase structure was found. The lattice parameter was found to be 8.441 Å for ZnFe2O4, 8.35 Å for NiFe2O4, and 8.349 Å for CuFe2O4. The Ni0.4Zn0.6Fe2O4 ferrite was sintered at three different temperatures: namely 1100°C, 1200°C, and 1300°C and similar temperature control was applied to Cu0.2Ni0.2Zn0.4Fe2O4 ferrite group. The energy band gap was calculated for Ni0.4Zn0.6Fe2O4 and Cu0.2Ni0.2Zn0.4Fe2O4 and was found to be 3.657 eV and 4.889 eV, respectively. The dielectric properties were investigated over a wide range using impedance spectroscopy and were found to decrease with the increase of frequency. Similar behavior was observed with the sintering temperature. In the same manner, the electric conductivity was found to decrease with the increase of frequency and sintering temperature as well. On the other hand, the electric resistivity was found to increase with both frequency and the sintering temperature.

Identification of Diabetic Retinal Exudates in Digital Color Images Using Support Vector Machine

Support vector machine (SVM) has become an increasingly popular tool for machine learning tasks involving classification. In this paper, we present a simple and effective method of detect and classify hard exudates. Automatic detection of hard exudates from retinal images is worth-studying problem since hard exudates are associated with diabetic retinopathy and have been found to be one of the most prevalent earliest signs of retinopathy. The algorithm is based on Discrete Cosine Transform (DCT) analysis and SVM makes use of color information to perform the classification of retinal exudates. We prospectively assessed the algorithm performance using a database containing 1200 retinal images with variable color, brightness, and quality. Results of the proposed system can achieve a diagnostic accuracy with 97.0% sensitivity and 98.7% specificity for the identification of images containing any evidence of retinopathy.

Reversal of multidrug resistance and antitumor promoting activity of 3-oxo-6β-hydroxy-β-amyrin isolated from Pistacia integerrima

The bioactive triterpenoid 3-oxo-6-β-hydroxy-β-amyrin(1)has been isolated from multiple plant sources.In this study,chloroform fraction of Pistacia integerrima extract was processed for the isolation of the compound.The compound identity was confirmed by advanced spectroscopy technique.X-ray crystallography was applied for molecular structure confirmation.In addition,compound 1 was screen for its activity on reversal of MDR(multidrug resistance)mediated by P-gp(P-glycoprotein).This was accomplished by using rhodamine123 exclusion on multidrug-resistant human ABCB1 gene transfected mouse T-lymphoma cell line.Outcomes revealed that MDR reversing effect was comparable to verapamil as positive control in vitro.Treatment of TPA-induced tumor promotion with 3-oxo-6β-hydroxy-β-amyrin led to reduction in the applied anti-tumor promotion experiment.The chemo-preventive effect of 3-oxo-6β-hydroxy-β-amyrin was comparable to curcumin as positive control based on the reduction of immediate early tumor antigen expression.Molecular docking by applying Autodock Vina 1 and i-GEMDOCK v 2.1 tools indicated that compound 1 gives good docking results,as determined by their fitness score and specificity.Moreover,results showed that compound 1 isolated from Pistacia integerrima precisely attached to a region where co-crystallized ligand for receptor previously existed.Our findings may explain the use of Pistacia integerrima plant extracts as an anticancer agent in folk medicine.

DDoS Attack Detection in Cloud Computing Based on Ensemble Feature Selection and Deep Learning

Intrusion Detection System(IDS)in the cloud Computing(CC)environment has received paramount interest over the last few years.Among the latest approaches,Deep Learning(DL)-based IDS methods allow the discovery of attacks with the highest performance.In the CC environment,Distributed Denial of Service(DDoS)attacks are widespread.The cloud services will be rendered unavailable to legitimate end-users as a consequence of the overwhelming network traffic,resulting in financial losses.Although various researchers have proposed many detection techniques,there are possible obstacles in terms of detection performance due to the use of insignificant traffic features.Therefore,in this paper,a hybrid deep learning mode based on hybridizing Convolutional Neural Network(CNN)with Long-Short-Term Memory(LSTM)is used due to its robustness and efficiency in detecting normal and attack traffic.Besides,the ensemble feature selection,mutualization aggregation between Particle Swarm Optimizer(PSO),Grey Wolf Optimizer(PSO),Krill Hird(KH),andWhale Optimization Algorithm(WOA),is used to select the most important features that would influence the detection performance in detecting DDoS attack in CC.A benchmark dataset proposed by the Canadian Institute of Cybersecurity(CIC),called CICIDS 2017 is used to evaluate the proposed IDS.The results revealed that the proposed IDS outperforms the state-of-the-art IDSs,as it achieved 97.9%,98.3%,97.9%,98.1%,respectively.As a result,the proposed IDS achieves the requirements of getting high security,automatic,efficient,and self-decision detection of DDoS attacks.

Securing Cloud Computing from Flash Crowd Attack Using Ensemble Intrusion Detection System

Flash Crowd attacks are a form of Distributed Denial of Service(DDoS)attack that is becoming increasingly difficult to detect due to its ability to imitate normal user behavior in Cloud Computing(CC).Botnets are often used by attackers to perform a wide range of DDoS attacks.With advancements in technology,bots are now able to simulate DDoS attacks as flash crowd events,making them difficult to detect.When it comes to application layer DDoS attacks,the Flash Crowd attack that occurs during a Flash Event is viewed as the most intricate issue.This is mainly because it can imitate typical user behavior,leading to a substantial influx of requests that can overwhelm the server by consuming either its network bandwidth or resources.Therefore,identifying these types of attacks on web servers has become crucial,particularly in the CC.In this article,an efficient intrusion detection method is proposed based on White Shark Optimizer and ensemble classifier(Convolutional Neural Network(CNN)and LighGBM).Experiments were conducted using a CICIDS 2017 dataset to evaluate the performance of the proposed method in real-life situations.The proposed IDS achieved superior results,with 95.84%accuracy,96.15%precision,95.54%recall,and 95.84%F1 measure.Flash crowd attacks are challenging to detect,but the proposed IDS has proven its effectiveness in identifying such attacks in CC and holds potential for future improvement.

An Optimized Approach for Spectrum Utilization in mmWave Massive MIMO 5G Wireless Networks

Massive multiple-input multiple-output(MIMO)systems that use the millimeter-wave(mm-wave)band have a higher frequency and more antennas,which leads to significant path loss,high power consumption,and server interference.Due to these issues,the spectrum efficiency is significantly reduced,making spectral efficiency improvement an important research topic for 5G communication.Together with communication in the terahertz(THz)bands,mmWave communication is currently a component of the 5G standards and is seen as a solution to the commercial bandwidth shortage.The quantity of continuous,mostly untapped bandwidth in the 30–300 GHz band has presented a rare opportunity to boost the capacity of wireless networks.The wireless communications and consumer electronics industries have recently paid a lot of attention to wireless data transfer and media streaming in the mmWave frequency range.Simple massive MIMO beamforming technology cannot successfully prevent interference between multiple networks in the current spectrum-sharing schemes,particularly the complex interference dispersed in indoor communication systems such as homes,workplaces,and stadiums.To effectively improve spectrum utilization and reduce co-channel interference,this paper proposes a novel algorithm.The main idea is to utilize the spectrum in software-defined mmWave massive MIMO networks through coordinated and unified management.Then,the optimal interference threshold is determined through the beam alignment method.Finally,a greedy optimization algorithm is used to allocate optimal spectral resources to the users.Simulation results show that the proposed algorithm improved spectral efficiency and reduced interference.

Thomson and rotation effects during photothermal excitation process in magnetic semiconductor medium using variable thermal conductivity

This study investigates a strong magnetic field acting over an elastic rotator semiconductor medium.The Thomson effect due to the magnetic field during the photothermal transport process is studied,and the thermoelectricity theory is used to explain the behavior of waves in the homogenous and isotropic medium under the effect of variable thermal conductivity.The variable thermal conductivity is considered as a linear function of the temperature.The two-dimensional deformation equations are used to describe the overlaps among plasma,electrical,thermal,and magneto-elastic waves.The charge density of inertia-particles is considered as a function of time for studying the induced electric current.The normal mode analysis is used to obtain the exact solutions of the physical field distributions as part of this phenomenon.To obtain the complete solutions of the physical field quantities,the certain mechanical loads,electromagnetic effects,thermal effects,and plasma recombination process are applied herein.The results of the physical distributions are graphically depicted and discussed in consideration of the internal heat source,rotation,and Peltier coefficient.

Predictors and willingness to take COVID-19 vaccine in Nigeria

Background:Coronavirus Disease 2019 constitutes a major threat worldwide with which the whole globe is confronted.Notwithstanding the urgent requirement for an effective vaccine,there is as yet an extensive lack of concern and hesitancy in accepting vaccines in Nigeria.Methods:Online survey conducted from January to December 2020 with 5,114 grown-ups,arbitrarily scrutinized to coordinate with the populace for age,and sexual orientation.The survey instrument assessed the willingness to accept COVID-19 approved vaccine,using a published scale of 15 items vaccine hesitancy scale.Results:About 3,667(71.7%)participants indicated a willingness to be vaccinated,while 598(11.7%)were unwilling and 849(16.6%)were indeterminate.Clarifying 32%of difference featured two higher-request logical variables:'unnecessary question'(r=0.51),including connivance belief,negative perspectives on specialists,and need for turmoil and'positive clinical benefits experiences'(r=−0.48),including solid expert correspondences and incredible National Health Insurance care.Hesitancy was found to be associated with lower adherence to isolating social principles.Conclusion:Hesitating to take the COVID-19 vaccine is spreading moderately across the general population.Public data on a vaccine that highlights prosocial benefits may be especially convincing.However,elements,such as subversion beliefs and taboos that develop a question and disintegrate social association will hinder vaccine take-up.

Heat transfer analysis of MHD rotating flow of Fe_(3)O_(4)nanoparticles through a stretchable surface

The flow of a magnetite-H_(2)O nanofluid has been considered among two rotating surfaces,assuming porosity in the upper plate.Furthermore,the lower surface is considered to move with variable speed to induce the forced convection.Centripetal as well as Coriolis forces impacting on the rotating fluid are likewise taken into account.Adequate conversions are employed for the transformation of the governing partial-differential equations into a group of non-dimensional ordinary-differential formulas.Numerical solution of the converted expressions is gained by means of the shooting technique.It is theoretically found that the nanofluid has less skin friction and advanced heat transport rate when compared with the base fluid.The effect of rotation causes the drag force to elevate and reduces the heat transport rate.Streamlines are portrayed to reveal the impact of injection/suction.

Effects of γ-irradiation and Deformation Temperature on Tensile Properties of Pb-2 mass% Sb Alloy

Effects ofγ-irradiation and deformation temperature（T）on the tensile properties of Pb-2mass% Sb alloys were studied.The samples were annealed at 458 Kfor 2hin air,then water quenched after they wereγ-irradiated（the different doses were 0.5,1.0,1.5,and 2.0 MGy）.The tensile properties were performed using stress-strain measurements at a constant strain rate（1.2×10^（-3） s^（-1））and at different T（303-393K）.It was found that at constant dose,the fracture stress（σF）decreases while the fracture strain（εF）increases as Tincreases.At particular T,σFincreases whileεFdecreases with increasing dose.The strain-hardening exponent（n）,which is the slope of the relation between ln（σ）and ln（ε）of the parabolic part of the stress-strain curve,was determined and its values increase as Tincreases and decrease as the dose increases.The value of the activation energy increases as the dose increases from 0.07 eV for un-irradiated sample to 0.1eV for the 2 MGy-irradiated sample.These values are in accordance with that needed for dislocation movement and ordering process.An interpretation of the results was given,based on the creation of point and line defects due toγ-irradiation,and that results in a distribution of beta phase（Sb-phase）,leading to a difficulty in the movement of dislocations,so there is an increase in alloy hardness.

FEM for Blood-Based SWCNTs Flow Through a Circular Cylinder in a Porous Medium with Electromagnetic Radiation

This work aims to study magnetohydrodynamic flow through a circular cylinder in a horizontal position of SWCNTs in blood as a base fluid in the existence of non-linear thermal radiation and heat source/sink.Three kinds of nanoparticles shapes are considered.The study is employed the finite element technique to explore and enhance the influences of essential parameters on temperature profiles and is debated the heat transport within blood injects with SWCNTs and exposes to electromagnetic radiation.The treatment with thermal analysis and heat transfer rate being a better substitute more than surgery and chemotherapy for cancer therapy.Utilizing of nanoparticles thermal features is a mounting area of nanomedicine field because of the probable for purposeful demolition of cancer cells.This remedy is relied on many parameters,including nanofluid thermal conductivity,nanoparticles volume fraction,thermal radiation and power and heat source.The numerical solutions for flow and heat transfer features are assessed for diverse governing parameters values.The obtained results are substantiated against the relevant numerical results in the published researches.Results show that both flow velocity and temperature increase for larger values of thermal radiation,heat source and SWCNTs volume fraction with lamina and cylinder shapes.Also,spherical shape of SWCNTs occurs high disturbances in velocity and temperature distribution in the case of cooled cylinder.