Showing papers by "University of Aden published in 2021"

Polysaccharides; Classification, Chemical Properties, and Future Perspective Applications in Fields of Pharmacology and Biological Medicine (A Review of Current Applications and Upcoming Potentialities)

Abstract: Polysaccharides are essential macromolecules which almost exist in all living forms, and have important biological functions, they are getting more attention because they exhibit a wide range of biological and pharmacological activities, such as anti-tumour, immunomodulatory, antimicrobial, antioxidant, anticoagulant, antidiabetic, antiviral, and hypoglycemia activities, making them one of the most promising candidates in biomedical and pharmaceutical fields. Polysaccharides can be obtained from many different sources, such as plants, microorganisms, algae, and animals. Due to their physicochemical properties, they are susceptible to physical and chemical modifications leading to enhanced properties, which is the basic concept for their diverse applications in biomedical and pharmaceutical fields. In this review, we will give insight into the most recent updated applications of polysaccharides and their potentialities as alternatives for traditional and conventional therapies. Challenges and limitations for polysaccharides in pharmaceutical utilities are discussed as well.

In-grown flower like Al-Li/Th- LDH@CNT nanocomposite for enhanced photocatalytic degradation of MG dye and selective adsorption of Cr (VI)

Abstract: Inner transition metal ions doped layered double hydroxides–embedded in CNTs have attracted increasing attention for wastewater treatment and renewable energy recently. In this work, the nanostructures of Al-Li/Th-LDH@CNT consisting of flower-like morphology were successfully synthesized by the elegant combination of exfoliated Al-Li/Th LDHs nano-sheets and F-CNTs using the hydrothermal method. The as-synthesized Al-Li@ThLDH-CNT nanocomposite is employed for MG dye photodegradation and selective adsorption of Cr (VI) ions. The Al-Li/Th-LDH@CNT nanocomposite has exhibited excellent visible-light-induced photocatalytic activity towards Malachite green (MG) dye, and almost 98% of (MG) dye is decolorized within 45 min. Studies probing the mechanism demonstrate that the photogenerated hydroxyl radical and holes play a vital role in the MG dye degradation process. Furthermore, the Al-Li/Th-LDH@CNT was tested to examine its selective adsorption behavior towards different metal ions at ultra-low trace levels by the ICP-MS technique. The adsorption behavior of Al-Li/Th-LDH@CNT displayed high removal percentage towards Cr6+ (94.1%), while as 86.7% and 83% for Al-Li and Al-Li-CNT adsorbents and the maximum adsorption capacities of Al-Li, Al-Li-CNT, and Al-Li/Th-LDH@CNT were found to be 156.2, 163.3 and 172.4 mg g-1respectively. Thus, preparing layered structure composite using a simple engineered route may open a new strategy to synthesize advanced materials having improved synergistic catalytic properties, which could be effectively used as highly efficient probes for environmental applications.

Theoretical and numerical analysis for transmission dynamics of COVID-19 mathematical model involving Caputo–Fabrizio derivative

Abstract: This manuscript is devoted to a study of the existence and uniqueness of solutions to a mathematical model addressing the transmission dynamics of the coronavirus-19 infectious disease (COVID-19). The mentioned model is considered with a nonsingular kernel type derivative given by Caputo–Fabrizo with fractional order. For the required results of the existence and uniqueness of solution to the proposed model, Picard’s iterative method is applied. Furthermore, to investigate approximate solutions to the proposed model, we utilize the Laplace transform and Adomian’s decomposition (LADM). Some graphical presentations are given for different fractional orders for various compartments of the model under consideration.

Evaluation of structural, elastic properties and nuclear radiation shielding competence of Nd3+ doped lithium-zinc-phosphate glasses

Abstract: Nd3+ doped lithium-zinc-phosphate glasses were synthesized by melt-quenching technique. FTIR spectra were recorded in the wavenumber range of 400–4000 cm−1. Elastic parameters such as Debye temperature and fractal bond connectivity were calculated. The results revealed that these parameters were influenced by the glass system's composition and dopant concentration. The mass and linear attenuation coefficients (MAC, LAC) of gamma-ray photons at the energy range from 0.015 to 15 MeV have been investigated using the Phy-X/PSD software program as well as the XCOM database program. Both MAC and LAC increase with the increase in the amount of Nd2O3. Also, the mean free path values and the half-value layer decrease while the density increases with the increase of the Nd2O3 content. Moreover, the fast neutron removal cross section was also presented and the results were compared with the concrete and commercial shielding glasses.

Compact UWB Vivaldi Tapered Slot Antenna

Abstract: In this paper compact Ultra Wideband (UWB) Vivaldi Tapered Slot Antenna (VTSA) is designed simply by changing its Microstrip to Slot line (M/S) transition. To explain the effect of transition’s shapes on the size and the performance of the UWB VTSA, four models (A–D) with detailed parametric studies are analyzed, designed, and fabricated. As compared to Model A, in Model D the size (42.9 mm × 29.28 mm = 1256.112 mm2) is reduced by 19.25%, and the bandwidth (10.34 GHz) is enhanced by 24.56%, in addition, it provides 6.51 dBi maximum realized gain, and stable end-fire radiation pattern. The validity of the proposed antennas is proven by hardware measurement results.

Maximal overlap discrete wavelet-packet transform aided microwave nondestructive testing

Abstract: The capability of microwave signals to penetrate inside composites and interact with the inner structure makes them a very attractive candidate for composite inspection. Various techniques of microwave nondestructive testing (NDT) are used for detecting disbonds in composites. Despite their promising results, these techniques suffer from poor spatial resolution due to the given features that do not significantly distinguish between the defect and defect-free regions. In this paper, a hybrid signal processing based on a refinement feature extraction method is employed to enhance the imaging efficiency of the disbond detection in composite material. This technique is based on scanning the composite material with an open-ended rectangular waveguide operating from 18 to 26.5 GHz and analyzing its reflections using the proposed hybrid signal processing method. Maximal overlap discrete wavelet packet transform is employed to provide significant informative features of each frequency point. The Bi-directional long short-term memory (Bi-LSTM) network approach is used to distinguish the significant features and the outliers. The Bi-LSTM classifies each inspected location into a defect or defect-free location. The findings presented in this paper show the advantages of the refinement method-aided microwave technique in detecting disbonds down to 1 mm with an accuracy rate of 88.84%, a significant advantage over any current disbond inspection technique.

Some Existence and Stability Criteria to a Generalized FBVP Having Fractional Composite p -Laplacian Operator

Abstract: In this paper, we consider a generalized Caputo boundary value problem of fractional differential equation with composite - Laplacian operator. Boundary value conditions of this problem are of three-point integral type. First, we obtain Green’s function in relation to the proposed fractional boundary value problem and then for establishing the existence and uniqueness results, we use topological degree theory and Banach contraction principle. Further, we consider a stability analysis of Ulam-Hyers and Ulam-Hyers-Rassias type. To examine the validity of theoretical results, we provide an illustrative example.

Influence of pH on the physical properties of CdS thin film and its photosensor application

Abstract: Synthesizing thin films on various substrates and serving as electrodes for photosensor is challenging task. In this work, influence of pH on structural and optical properties of cadmium sulfide (CdS) thin film investigated using a chemical bath deposition method on a glass substrate. The fabricated CdS film was characterized by using an X-ray diffraction pattern and field emission scanning electron microscopy (FE-SEM). From the structural analysis study, it shows that CdS thin film has a hexagonal phase structure. FE-SEM analysis study revealed uniform and homogenous deposition on the glass. Moreover, at pH = 10, the smallest crystal size obtained ~3 nm. From optical properties, analysis shows that CdS has a 3.12 eV–3.13 eV bandgap. The electrical parameters for films show substantial growth in current after light illumination. Also, the photosensitivity found that their sensitivity to light increases with reduction in the pH value.

Assessing antimicrobial resistance, utilization and stewardship in Yemen: An exploratory mixed-methods study

Abstract: Antimicrobial resistance (AMR), largely driven by irrational use of antimicrobials, is a global, multi-faceted problem calling for a complete understanding of all contributory factors for effective containment. In conflict settings, war-wounds and malnutrition can combine with existing social determinants to increase demand for antibiotics, compounding irrational use. In this study, we focus on Yemen, a low-income country with active conflict for the last five years, and analyze the current status of awareness and stewardship efforts regarding AMR. We performed a survey of prescribers/physicians and pharmacists to describe perceptions of AMR prevalence, antibiotic use practices and stewardship in Yemen, supported by a non-systematic scoping literature review and a key informant interview. Participants (96%, n=57) reported a perceived high AMR prevalence rate. Prescribers (74%, 20/27) reported pressure to prescribe broad-spectrum antibiotics. In the majority of cases (81%, 22/27), Antimicrobial Sensitivity Tests (AST) were not performed to inform antibiotic choice. The main barrier to AST was cost. Most pharmacists (67%, 18/27) sold antibiotics without prescriptions. Amoxicillin (including amoxicillin-clavulanate) was the most-commonly prescribed (63%, 17/27) or dispensed (82%, 22/27) antibiotic. AST was rated the least important solution to AMR in Yemen. While there was awareness of a high AMR rate, stewardship is poor in Yemen. We note that barriers to the use of AST could be addressed through the deployment of low-cost AST kits. Compulsory continuing education emphasizing the use of AST to guide prescribing and patients’ awareness programs could help avoid irrational use.

Knowledge, Attitudes and Practices Survey of Medication Safety among Community Pharmacists in Aden-Yemen

Abstract: Introduction: All health professionals' participation is essential for ensuring quality and successful national post-marketing surveillance programs. This study aimed to assess the knowledge, attitudes, and practices (KAP) among Yemeni community pharmacists (CPs) regarding medication safety in a poor-resource setting. Methods: A survey was conducted among CPs in Aden governorate. The tool comprised of demographic profile, knowledge, attitude, and practice aspects of medication safety. The survey also studied the opinion about the future and benefits of Adverse Drug Reaction (ADR) reporting in Yemen. The data collected was analyzed using descriptive statistics such as frequencies, percentages, and means (SD). Results: A total of 450 CPs were enrolled in the study. Most of the participants were males (75%) with a bachelor's degree (91.9%) and between 3-6 years of experience (28%). The majority of CPs had good knowledge regarding the perception and objectives of Pharmacovigilance (PV) and ADRs. Approximately 41% of participants knew the purpose of PV as an essential system for public health and safety concerning drug use. Additionally, the Yemeni pharmacists had a positive attitude towards the reporting system. Approximately 84% of responders admitted that PV is the responsibility of the pharmacists. The majority of the participants (80%) declared no reporting form available at their workplace. According to CPs, 59% said that relevant authorities do not widely promote ADR reporting in Yemen, and 57% replied that the patient's lack of information is an obstacle in the reporting system. Approximately 89% of the CPs believed that reporting ADRs would improve patient safety. Conclusions: The CPs have a positive attitude towards PV and an acceptable degree of knowledge. However, the practice level should be upraised.

Implementation of an educational module on nosocomial infection control measures: a randomised hospital-based trial

Abstract: Previous cross-sectional studies have reported limited knowledge and practices among nurses regarding controlling nosocomial infections (NIs). Even though health institutions offer many irregular in-service training courses to solve such issues, a three year-nursing educational programme at institutions is not adequate to enable nurses to handle NIs. Therefore, this study aims to evaluate the implementation of an educational module on NIs control measures among Yemeni nurses. A single-blinded randomised hospital-based trial was undertaken involving 540 nurses assigned to two intervention groups and a waitlist group. Intervention group-1 received a face-to-face training course comprising 20 h spread over six weeks and a hard copy of the module, while intervention group-2 only received the hard copy of the module “without training”. In contrast, the waitlist group did not receive anything during the period of collecting data. A self-administered NI control measures-evaluation questionnaire was utilised in collecting the data from the participants; before the intervention, at six weeks and 3 months after the end of the intervention. The period of data collection was between 1st May and 30th October 2016. The results from collecting and analysing the data showed a statistically significant difference in the mean knowledge scores between the intervention groups that were detectable immediately post-intervention with a mean difference (MD) of 4.31 (P < 0.001) and 3 months after the end of the intervention (MD = 4.48, P < 0.001) as compared to the waitlist group. Similarly, the results showed a statistically significant difference in the mean practice scores between the intervention groups immediately post-intervention (MD = 2.74, P < 0.001) and 3 months after the intervention (MD = 2.46, P < 0.001) as compared to the waitlist group. Intervention-1 (face-to-face training + module) was more effective than intervention-2 (module only) in improving Yemeni nurses’ knowledge and practices regarding NI control measures compared to the waitlist group. The findings of this study found that intervention-1 could be offered to nurses in the form of an in-service training course every six months. The NI course should also be included in nursing curricula, particularly for the three-year-nursing diploma in Yemen. Nosocomial infection educational module for nurses ISRCTN19992640 , 20/6/2017. The study protocol was retrospectively registered.

Domination topological properties of some chemical structures using φp-polynomial approach

Abstract: φp -Polynomial is one way to represent a graph algebraically, and it has a major role in theoretical chemistry. It is used in the calculation of the exact values of many topological indices that depend on the P set degree. In this paper, we study the φp -Polynomial by using minimal and minimum dominating sets for Nicotine, Aspirin, and Anthraquinone. Using those φp -Polynomials, some domination and domination topological indices are derived. Also, the results are graphically interpreted.

On the ψk-polynomial of graph

Abstract: In this paper, for every k-degree distance we define ψk-Polynomial of a connected graph G=(V,E) as where ψk(i,j) is the number of edges uv in G such that {dk(v), dk(u)}={i,j} and dk(v), dk(u) are the kth degree distance of v and u, and δk, ∆k are the minimum and maximum kth distance degrees respectively. We compute the ψ2-Polynomial of some standard graphs and some graph operations. Also ψ2-Polynomial for honeycomb network and Graphene are obtained with their plotting in 3D.

Evaluation of markers of periodontal disease development on based on the study of the microbial composition of various biotopes of the oral cavity

Abstract: Summary. The composition of supragingival and subgingival dental plaque, gingival and oral fluid, dentogingival or periodontal pocket, are a valuable diagnostic medium for non-invasive diagnosis of inflammatory periodontal diseases, since they contain a wide variety of microorganisms, many of which are markers. Purpose — non-invasive assessment of markers of periodontal diseases based on the study of the microbial composition of various biotopes of the oral cavity by PCR. Мaterials and methods. Non-invasive diagnosis risk factors, in particular, the presence of periodontal pathogenic microflora, provided for the study of various biotopes of the oral cavity — plaque, oral and gingival fluids, the composition of the dental pocket by applying a high-quality PCR diagnostic method using commercial DNA-express kits (LLC NPF «Litech», Russia). Results. A comparative study of markers of the development of periodontal diseases using a qualitative version of the PCR test system in samples of subgingival plaque and dental pocket contents of individuals with initial stage I periodontitis showed 3.1 times greater prevalence of the representative of the yellow complex — Aggregatibacter actinomycetemcomitans, 1.4 times more often than the representative of the red complex P. gingivalis. In the studied material of supragingival plaque, gingival and oral fluid of individuals with gingivitis induced by dental biofilm, the representative of the yellow complex Aggregatibacter actinomycetemcomitans prevails 2.6 times more often than representatives of the red complex — P. gingivalis and Tannerella forsythia, 1.4 times the orange complexFusobacterium nucleatum. In samples of supragingival plaque in individuals with clinically healthy gums with loss of periodontal tissue, representatives of the microflora that form orange, red and yellow complexes most often predominate. Conclusion. The study of supragingival and subgingival plaque, gingival and oral fluid, and the dentogingival pocket using a PCR test system allows timely detection of markers of the development of inflammatory diseases, regardless of clinical condition of periodontal disease.

On Reciprocal leap function of graph

Abstract: In this research work, we define the first and second Reciprocal leap functions of graph , where the d2(υ) is the second degree of the vertices. We compute the first and second Reciprocal leap func...

Forgotten domination, hyper domination and modified forgotten domination indices of graphs

Abstract: For each vertex υ ϵ V(G), the domination degree denoted by dd (v) and defined as the number of minimal dominating sets of G which contains υ. In this paper, we will define new indices depend on dom...

Dispensing of Banned Phenolphthalein and Ketoconazole: Simulated Patients Method

Abstract: Introduction: Banned and harmful medicines can affect patient’s health, safety and life. There are two medicines available in Aden community pharmacies (phenolphthalein (PP) and ketoconazole (KZ)) that are globally banned. The objective of this study was to evaluate the availability and dispensing of banned phenolphthalein and ketoconazole by community pharmacists. Methods: A preliminary cross-sectional simulated patients method was carried out. The study gathered data on dispensing behavior. Simulated patients were trained to access the availability of banned drugs existing in the community pharmacies. The availability of these two banned drugs was observed and recorded. The pharmacists were asked about the availability of a PP laxative for treating constipation called in Yemen a khat laxative (Sharbat Alkhat) and KZ for fungal infections in 50 convenient samples of community pharmacies that were selected based on ease of access by the simulated patients. Results: PP was found in 3/50 (6%) pharmacies, while 31/50 (62%) pharmacies kept KZ in the premise. Conclusion: The availability of these drugs in Yemeni pharmacies is worrisome. It can affect the safety of the public.

Domination topological indices and their polynomials of a firefly graph

Abstract: Let G be a connected graph of order n. Some new topological indices called domination topological indices are interduced recently [10]. In this research work we calculate some domination topologica...

Radiological and gamma-ray shielding parameters of cement raw materials samples used in Yemen

Abstract: The natural radioactivity of 16 cement raw materials samples from Yemen was determined. The average activity concentrations of 226Ra, 232Th and 40K were 32, 18 and 239 Bq.kg−1 in limestone samples, 43, 35 and 1081 Bq.kg−1 in clay samples, 40, 36 and 840 Bq.kg−1 in sandstone samples, 29, 11 and 161 Bq.kg−1 in iron ore samples, 29, 17 and 166 Bq.kg−1 in raw gypsum samples and 48, 23 and 690 Bq.kg−1 in pozzolana samples, respectively. The results indicated that the highest radionuclides concentrations for measured samples were in clay samples, whereas the lowest values were in iron ore samples. Radiological parameters such as external hazard index (Hex), radium equivalent (Raeq), internal hazard index (Hin) and gamma index (Iϒ) were assessed. Moreover, the chemical composition of these raw materials was measured and simulated for their gamma-ray shielding properties. Radiation protection coefficients such as mass attenuation coefficient (MAC), atomic cross section (AC), electron cross section (EC), effective atomic number (Zeff) and electron density (Neff) have been estimated in the photon energy range from 0.015 to 15 MeV using Phy-X/PSD software program. The results indicated that the highest values of the gamma-ray shielding parameters were at the energy 0.015 MeV, while the lower values were at the energy 15 MeV. Also, the results indicated that the iron ore sample has the best gamma-ray shielding properties among other investigated raw materials.

Assessment of radon exhalation rate, radon concentration and annual effective dose of some building materials samples used in Yemen

Abstract: Radon gas has been recognized as one of the health hazards to humans. Building materials used for the construction of houses, which are considered as one of the major sources of this gas in indoor environments. The radon exhalation rate, radon concentration as well as the annual effective dose for 46 samples of building materials (granite, ceramic, marble, mosaic, rocks, gypsum, block and red brick) used in Yemen were measured using two methods. The can technique, containing CR-39 solid-state detector, and active method containing AlphaGuard detector were used. The results obtained from passive and active techniques were found in good agreement. The results showed that the highest values of radon exhalation rate, radon concentration and the annual effective dose indoor and outdoor were 0.93 ± 0.020 Bqm−2 h−1, 186.48 ± 3.73 Bqm−3, 4.7 ± 0.141 and 1.76 ± 0.053 mSvy−1 for granite samples, whereas the lowest values were 0.0076 ± 0.001 Bqm−2 h−1, 1.51 ± 0.03 Bqm−3, 0.04 ± 0.001 and 0.01 ± 0.001 mSvy−1 for the ceramic samples. The results also showed that the radon exhalation rate, as well as the annual effective dose, was found below the world average values of 57.600 Bq m−2 h−1, 1100 μSv y−1 with exception of some samples. The values of radon concentrations for granite samples were in the range of activity levels from 200 to 600 Bq m−3 recommended by (ICRP, 1994).

Fast and Accurate Calculations of Fourth-Order Non-self-adjoint Sturm–Liouville Eigenvalues for Problems in Physics and Engineering

Abstract: Finding the eigenvalues of non-self-adjoint boundary value problems is a very difficult task, especially when the problems are of higher-order or when high-index eigenvalues are required. In fact, the lack of oscillation theorems of non-self-adjoint problems as well as the distribution and scatteration of the eigenvalues in the complex plane, makes the computational process of the eigenvalues a strong and difficult challenge. In this paper, we propose a fast and accurate numerical technique based on the Chebyshev spectral collocation method for approximating the eigenvalues of fourth-order non-self-adjoint Sturm–Liouville boundary value problems. This technique transforms the non-self-adjoint problem into a generalized eigenvalue problem by employing the spectral differentiation matrices to determine the derivatives of Chebyshev polynomials at the Chebyshev–Gauss–Lobatto nodes. The excellent performance of the suggested technique is investigated by considering three numerical examples among which singular ones. The numerical results and comparison with other methods indicate that this technique is easy to implement, considerably accurate and requires less computational costs even when high-index eigenvalues are required.