Developing drug delivery systems based on alginate and brushite

Developing drug delivery systems based on alginate and brushit

UAV Trajectory Optimization for Directional THz Links Using Deep Reinforcement Learning

As an alternative solution for quick disaster recovery of backhaul/fronthaul links, in this paper, a dynamic unmanned aerial vehicles (UAV)-assisted heterogeneous (HetNet) network equipped with directional terahertz (THz) antennas is studied to solve the problem of transferring traffic of distributed small cells. To this end, we first characterize a detailed three-dimensional modeling of the dynamic UAV-assisted HetNet, and then, we formulate the problem for UAV trajectory to minimize the maximum outage probability of directional THz links. Then, using deep reinforcement learning (DRL) method, we propose an efficient algorithm to learn the optimal trajectory. Finally, using simulations, we investigate the performance of the proposed DRL-based trajectory method

LoS Coverage Analysis for UAV-based THz Communication Networks: Towards 3D Visualization of Wireless Networks

Terahertz (THz) links require a line-of-sight (LoS) connection, which is hard to be obtained in most scenarios. For THz communications, analyses based on LoS probability are not accurate, and a new real LoS model should be considered to determine the LoS status of the link in a real 3D environment. Considering unmanned aerial vehicle (UAV)-based THz networks, LoS coverage is analyzed in this work, where nodes are accurately determined to be in LoS or not. Specifically, by modeling an environment with 3D blocks, our target is to locate a set of UAVs equipped with directional THz links to provide LoS connectivity for the distributed users among the 3D obstacles. To this end, we first characterize and model the environment with 3D blocks. Then, we propose a user-friendly algorithm based on 3D spatial vectors, which determines the LoS status of nodes in the target area. In addition, using 3D modeling, several meta-heuristic algorithms are proposed for UAVs' positioning under 3D blocks in order to maximize the LoS coverage percentage. In the second part of the paper, for a UAV-based THz communication network, a geometrical analysis-based algorithm is proposed, which jointly clusters the distributed nodes and locates the set of UAVs to maximize average network capacity while ensuring the LoS state of distributed nodes among 3D obstacles. Moreover, we also propose a sub-optimal hybrid k-means-geometrical-based algorithm with a low computational complexity that can be used for networks where the topology continuously changes, and thus, users' clustering and UAVs' positioning need to be regularly updated. Finally, by providing various 3D simulations, we evaluate the effect of various system parameters such as the number and heights of UAVs, as well as the density and height of 3D obstacles on the LoS coverage

Distribution of Enterotoxigenic Escherichia coli among E. coli isolates from diarrheal samples referred to educational hospitals in Tehran-Iran

Background: Introduction: Enterotoxigenic Escherichia coli (ETEC) is the most important bacterial cause of watery  travelers' diarrhea  in  developing countries. Watery diarrhea is can cause serious life-threatening dehydration. ETEC was caused diarrhea by the secretion of two heat-labile enterotoxins (LTs) and the heat-stable enterotoxins (STs) which increase intestinal secretion. Routine laboratory methods are not appropriate to detect ETEC and other diarrheagenic E. coli pathotypes. The molecular techniques such as PCR are rapid and accurate methods that have been developed for detection of ETEC. We were recognized ETEC by PCR on lt and st genes from E. coli isolates from patients with diarrhea collected from selected Tehran educational hospitals.Materials and Methods: The E. coli isolates were collected from total 140 patients with diarrhea and 110 patients without diarrhea using culture and IMViC test. DNA was extracted by boiling method and the presence of the uidA, lt and st genes was detected by PCR.Results: Among 140 E. coli isolates from diarrheal stools 5 (3.6%) isolates were positive for, just lt gene, 3 (2.1%) co-amplified for both lt/st and 1 (0.7%) was positive for just the st gene which were considered as ETEC. In the E. coli isolates from non-diarrheal control samples just one (0.9%) isolate was positive for both lt and st genes.Conclusion: The results showed that the ETEC as a significant cause of diarrhea, usually ignored by laboratories using traditional methods. Sometimes the ETEC causes severe diarrhea and can threaten for patient's life. Thus a rapid diagnostic test such as PCR can be very helpful in the treatment of patients

Profitability and liquidity: an empirical investigation of Islamic banks in Malaysia and United Kingdom

The banking sector plays a significant role in the economy of a country, Islamic banking has proven itself to be feasible and sustainable during the last decades. However, with the uncertainties that the world economies are facing in the last few years, the feasibility and sustainability of Islamic banking finance remains debatable. Hence this study aims to investigate macroeconomic and bank-specific factors that affect the Islamic banks profitability and liquidity in United Kingdom and Malaysia. The bank-specific indicators include capital adequacy, asset quality, liquidity, bank size; while the macroeconomic factors are GDP growth rate, inflation rate and lending rate. The study utilized balanced data between 2006 and 2018 of 12 Malaysian Islamic banks 4 UK Islamic banks. Panel Autoregressive Distributive Lag and Panel Vector Autoregressive models were employed to estimate indicators effects and relationship among variables. Impulse Response Function and Toda-Yamamoto were used to assess the impact of global financial crisis and causal relationships among the variables. The study reveals that capital adequacy has negative influence and asset quality has moderate negative effect on profitability of Islamic banks in both countries and global financial crisis was found to have no significance effect. Furthermore, profitability causes GDP and lending rate and Liquidity causes GDP and inflation rate while there exists a bidirectional relationship between liquidity and lending rate. This study also supports earlier studies that indeed, Islamic banks to a certain extent are also insulated against the financial crisis. The implication of our finding is that Islamic banks do not require high capital and asset quality to be liquid and profitable and thus for sustainability. Bank Negara and Bank of England may formulate policies that will facilitate new entries into Islamic banking since they are found to be less affected by financial crise