Efficient Pricing Technique for Resource Allocation Problem in Downlink OFDM Cognitive Radio Networks

In this paper, the problem of resource allocation in OFDM-based downlink cognitive radio (CR) networks has been proposed. The purpose of this research is to decrease the computational complexity of the resource allocation algorithm for downlink CR network while concerning the interference constraint of primary network. The objective has been secured by adopting pricing scheme to develop power allocation algorithm with the following concerns: (i) reducing the complexity of the proposed algorithm and (ii) providing firm power control to the interference introduced to primary users (PUs). The performance of the proposed algorithm is tested for OFDM- CRNs. The simulation results show that the performance of the proposed algorithm approached the performance of the optimal algorithm at a lower computational complexity, i.e., O(NlogN), which makes the proposed algorithm suitable for more practical applications

Distribution of arylamine N-acetyltransferase 2 (NAT2) genotypes among Omanis

Objective: to determine the genotypes of arylamine N-acetyltransferase (NAT2) among 127 unrelated apparently healthy Omanis. Method: Identify the most common known polymorphisms of NAT*2 gene namely, G191A, C282T, C341T, C481T, G590A, A803G and G857A using PCR-RFLP analysis. Results: Eleven allele variants (3 alternative) and 30 different genotypes were determined. The commonest alleles were found to be NAT*5B, NAT2*6A and NAT*4 with corresponding frequencies of 0.362, 0.248 and 0.189 respectively. The overall frequency of rapid acetylator alleles was 0.25. Conclusion: A new allele variant containing G590A, C282T and T341C polymorphisms was found in one subject (was named NAT2*5J). The commonest genotypes were found to be 5B/5B, 5B/6A, 4/5B, 4/6A with frequencies 0.165, 0.157, 0.118, 0.110 and 0.079 respectively.

Aging Reduces L-type Calcium Channel Current and the Vasodilatory Response of Small Mesenteric Arteries to Calcium Channel Blockers

Calcium channel blockers are widely used to treat cardiovascular disease (CVD) including hypertension. As aging is an independent risk factor for CVD, the use of calcium channel blockers increases with increasing age. Hence, this study was designed to evaluate the effect of aging on the sensitivity of small mesenteric arteries to L-type voltage-gated calcium channel (LTCC) blockers and also to investigate whether there was a concomitant change in calcium current density. Third order mesenteric arteries from male F344 rats, aged 2.5 - 3 months (young) and 22 - 26 months (old) were mounted on wire myograph to measure the tension during isometric contraction. Arteries were contracted with 100 mM KCl and were then relaxed in a cumulative concentration-response dependent manner with nifedipine (0.1nM - 10 µM), verapamil (0.1nM-10 µM) or diltiazem (0.1nM - 10µM). Relaxation-concentration response curves produced by cumulative concentrations of three different calcium channel blockers (CCBs) in arteries of old rats were shifted to the right with statistically significant IC50s. pEC50 ± s.e.m: (8.37 ± 0.06 vs 8.04 ± 0.05 , 7.40 ± 0.07 vs 6.81 ± 0.04 and 6.58 ± 0.07 vs 6.34 ± 0.06) in young vs old. It was observed that the maximal contractions induced by 100 mM KCl, phenylephrine and reversed by sodium nitroprusside were not different between young and old groups. However, Bay K 8644 increased resting tension by 23±4.8% in young arteries and 4.7±1.6% in old arteries. LTCC current density were also significantly lower in old arteries (-2.77 ± 0.45 pA/pF) compared to young arteries (-4.5 ± 0.40 pA/pF); with similar steady-state activation and inactivation curves. Parallel to this reduction, the expression of Cav1.2 protein was reduced by 57 ± 5% in arteries from old rats compared to those from young rats. In conclusion, our results suggest that aging reduces the response of small mesenteric arteries to the vasodilatory effect of the CCBs and this may be due to, at least in part, reduced current density of LTCC

May measurement month 2018: an analysis of blood pressure screening in Libya.

Elevated blood pressure (BP) is an important public health concern and leads to several adverse cardiovascular outcomes. In the stepwise survey done in Libya by the Libyan Cardiac Society and National Centre for Disease Control in 2009, the percentage of hypertension was 40.6%. To raise awareness of high BP and to highlight the size of the problem and the need for screening. A cross-sectional opportunistic study included men and women aged ≥18 years. Blood pressure was measured three times and a questionnaire was completed. Hypertension was defined as BP ≥140/90 mmHg based on the mean of the 2nd and 3rd readings, or on antihypertensive treatment. Among 7279 participants, the mean age was 44.3 ± 14.8 years, 57.8% male, 2567 (35.3%) of the participants had hypertension of whom 63.4% were aware of having hypertension, 55.8% on medication, and of those on medication 50.9% had controlled BP. This survey identified a high proportion of individuals with high BP, which highlights the need for a more strategic approach to fighting hypertension

Hybrid denture acrylic composites with nanozirconia and electrospun polystyrene fibers

The processing and characterization of hybrid PMMA resin composites with nano-zirconia (ZrO2) and electrospun polystyrene (PS) polymer fibers were presented in this study. Reinforcement was selected with the intention to tune the physical and mechanical properties of the hybrid composite. Surface modification of inorganic particles was performed in order to improve the adhesion of reinforcement to the matrix. Fourier transform infrared spectroscopy (FTIR) provided successful modification of zirconia nanoparticles with 3-Methacryloxypropyltrimethoxysilane (MEMO) and bonding improvement between incompatible inorganic nanoparticles and PMMA matrix. Considerable deagglomeration of nanoparticles in the matrix occurred after the modification has been revealed by scanning electron microscopy (SEM). Microhardness increased with the concentration of modified nanoparticles, while the fibers were the modifier that lowers hardness and promotes toughness of hybrid composites. Impact test displayed increased absorbed energy after the PS electrospun fibers had been embedded. The optimized composition of the hybrid was determined and a good balance of thermal and mechanical properties was achieved

Proceedings of First Conference for Engineering Sciences and Technology: Vol. 2

This volume contains contributed articles of Track 4, Track 5 & Track 6, presented in the conference CEST-2018, organized by Faculty of Engineering Garaboulli, and Faculty of Engineering, Al-khoms, Elmergib University (Libya) on 25-27 September 2018. Track 4: Industrial, Structural Technologies and Science Material Track 5: Engineering Systems and Sustainable Development Track 6: Engineering Management Other articles of Track 1, 2 & 3 have been published in volume 1 of the proceedings at this lin