Al Ain University of Science and Technology

About: Al Ain University of Science and Technology is a education organization based out in Al Ain, United Arab Emirates. It is known for research contribution in the topics: Higher education & Computer science. The organization has 369 authors who have published 1077 publications receiving 7930 citations.

Cognitive Chaotic UWB-MIMO Detect-Avoid Radar for Autonomous UAV Navigation

Abstract: A cognitive detect and avoid radar system based on chaotic UWB-MIMO waveform design to enable autonomous UAV navigation is presented. A Dirichlet-process-mixture-model (DPMM)-based Bayesian clustering approach to discriminate extended targets and a change-point (CP) detection algorithm are applied for the autonomous tracking and identification of potential collision threats. A DPMM-based clustering mechanism does not rely upon any a priori target scene assumptions and facilitates online multivariate data clustering/classification for an arbitrary number of targets. Furthermore, this radar system utilizes a cognitive mechanism to select efficient chaotic waveforms to facilitate enhanced target detection and discrimination. We formulate the CP mechanism for the online tracking of target trajectories, which present a collision threat to the UAV navigation; thus, we supplement the conventional Kalman-filter-based tracking. Simulation results demonstrate a significant performance improvement for the DPMM-CP-assisted detection as compared with direct generalized likelihood-ratio-based detection. Specifically, we observe a 4-dB performance gain in target detection over conventional fixed UWB waveforms and superior collision avoidance capability offered by the joint DPMM-CP mechanism.

A Novel Coplanar-Strip-Based Excitation Technique for Design of Broadband Circularly Polarization Antennas With Wide 3 dB Axial Ratio Beamwidth

Abstract: In this communication, a novel excitation technique for the design of a single-point-fed compact low-profile wide-slot antennas with broadband circular polarization (CP) and wide 3 dB axial ratio (AR) beamwidth is presented. Two inverted L-shaped parasitic strips placed coplanar to the microstrip line of an asymmetric coplanar waveguide (CPW) and a horizontal strip that protrudes from the vertical edge of the backside ground plane of the substrate are used for CP excitation. The overall footprint of the structure is only $L_{s} \times W_{s} = 0.3\lambda _{0} \times 0.28\lambda _{0}$ when measured at the lowest operating frequency. The antenna prototype has been experimentally validated. The measured results indicate that a wide impedance bandwidth of 72% (2.26–4.85 GHz) and a CP bandwidth of 66% (2.44–4.87 GHz) can be achieved. In addition to the wideband characteristics in terms of the impedance bandwidth and CP, a stable bidirectional radiation pattern with a wide 3 dB beamwidth of 85° ± 5° is obtained for 58% of the total CP bandwidth without involving any complex circuitry. Furthermore, by placing a flat metallic reflector behind the antenna, a unidirectional radiation pattern is produced without changing the geometrical dimensions of the proposed antenna. The average realized gain of the antenna without a reflector is 3.3 dBi, whereas it increases up to 6.3 dBi with the substrate-size reflector.

Obesity and its associated risk factors among school-aged children in Sharjah, UAE.

Abstract: Background The most prevalent nutritional disorders worldwide are childhood overweight or obesity. Various factors clearly contribute to the childhood obesity epidemic. The aim of this study is to investigate the prevalence of childhood obesity in children of primary schools, and determine the influence of eating behavior and lifestyle in such a condition. Methods The study based on a cross sectional survey including school children aged 6-11 years. Pupils were from different schools in Sharjah, UAE. Outcome measures used in this study covered health characteristics; child habits and lifestyle; disease status and medication. Results The number of pre-validated surveys distributed was 932 and those returned counted to 678, giving a response rate of 72.8%. More than half (379; 55.9%) of the participants were females and 191 (28.2%) of the children were obese or overweight. Almost one quarter (162; 23.9%) of the children was physically inactive. Additionally, candy and fast food consumption was significantly high (370; 54.6%) and (324; 47.8%) respectively. Participant's food, age and time spent on TV were significantly associated with body mass index (BMI). Conclusion Prevalence of overweight and obesity in the Emirate of Sharjah is high in both genders and across all ages of the study population. Contributing factors may include; sedentary lifestyle, consumption of unhealthy food and family history. There is a need for an immediate attention and measures to reduce the prevalence of obesity and associated diseases.

Characterization of human serum albumin's interactions with safranal and crocin using multi-spectroscopic and molecular docking techniques

Abstract: Interaction mechanisms of human serum albumin (HSA) with safranal and crocin were studied using UV–Vis absorption, fluorescence quenching and circular dichroism (CD) spectroscopies as well as molecular docking techniques. Changes in absorbance and fluorescence of HSA upon interactions with both compounds were attributed to their binding to amino acid chromophores located in subdomains IIA and IIIA. Fluorescence secondary inner filter effect was excluded using 278 nm and 340 nm as the wavelengths of HSA's excitation and fluorescence while safranal and crocin absorbed at 320 nm and 445 nm, respectively. Stern-Volmer model revealed a static quenching mechanism involve the formation of non-fluorescent ground state complexes. Stern-Volmer, Hill, Benesi-Hilbrand and Scatchard models gave apparent binding constants ranged in 4.25 × 103 - 2.15 × 105 for safranal and 7.67 × 103 - 4.23 × 105 L mol−1 for crocin. CD measurements indicated that 13 folds of safranal and crocin unfolded the α-helix structure of HSA by 7.47–21.20%. In-silico molecular docking revealed selective exothermic binding of safranal on eight binding sites with binding energies ranged in −3.969 to −6.6.913 kcal/mol. Crocin exothermally bound to a new large pocket located on subdomain IIA (sudlow 1) with binding energy of −12.922 kcal/mol. These results confirmed the formation of HSA stable complexes with safranal and crocin and contributed to our understanding for their binding characteristics (affinities, sites, modes, forces … etc.) and structural changes upon interactions. They also proved that HSA can solubilize and transport both compounds in blood to target tissues. The results are of high importance in determining the pharmacological properties of the two phytochemical compounds and for their future developments as anticancer, antispasmodic, antidepressant or aphrodisiac therapeutic agents.

Synthesis, characterization, and antimicrobial evaluation of oxadiazole congeners.

Abstract: A series of 1,3-oxazole, 1,3-thiazole, isomeric 1,2,4-oxadiazole, 1,3,4-oxadiazole, and 1,2,3,4-tetrazole heterocycles was synthesized. All the compounds shared as a common feature the presence of a 4-hydroxyphenyl substituent. The structures of the synthesized compounds were confirmed by MS, 1H-NMR, and elemental analysis. In vitro antimicrobial activity for all the newly synthesized compounds at concentrations of 200-25 μg/mL was evaluated against Gram+ve organisms such as methicillin-resistant Staphylococcus aureus (MRSA), Gram–ve organisms such as Escherichia coli (E. coli), and the fungal strain Aspergillus niger (A. niger) by the cup plate method. Ofloxacin and ketoconazole (10 μg/mL) were used as reference standards for antibacterial and antifungal activity, respectively. Compounds 15, 16, and 20 showed notable antibacterial and antifungal activities at higher concentrations (200 μg/mL), whereas 17-19 were found to display significant antibacterial or antifungal activity (25-50 μg/mL) against the Gram+ve, Gram–ve bacteria, or fungal cells used in the present study.