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SARS-CoV-2, a novel Corona virus strain, was first detected in Wuhan, China, in December 2019. As of December 16, 2021, almost 4,822,472 people had died and over 236,132,082 were infected with this lethal viral infection. It is believed that the human immune system is thought to play a critical role in the initial phase of infection when the viruses invade the host cells. Although some effective vaccines have already been on the market, researchers and many bio-pharmaceuticals are still working hard to develop a fully functional vaccine or more effective therapeutic agent against the COVID-19. Other efforts, in addition to functional vaccines, can help strengthen the immune system to defeat the corona virus infection. Herein, we have reviewed some of those proven measures, following which a more efficient immune system can be better prepared to fight viral infection. Among these, dietary supplements like- fresh vegetables and fruits offer a plentiful of vitamins and antioxidants, enabling to build of a healthy immune system. While the pharmacologically active components of medicinal plants directly aid in fighting against viral infection, supplementary supplements combined with a healthy diet will assist to regulate the immune system and will prevent viral infection. In addition, some personal habits, like- regular physical exercise, intermittent fasting, and adequate sleep, had also been proven to aid the immune system in becoming an efficient one. Maintaining each of these will strengthen the immune system, allowing innate immunity to become a more defensive and active antagonistic mechanism against corona-virus infection. However, because dietary treatments take longer to produce beneficial effects in adaptive maturation, personalized nutrition cannot be expected to have an immediate impact on the global outbreak.

One of the most common and useful forms of medical intervention is anticoagulant therapy and it is the mainstay of treatment and prevention of thrombosis in different clinical settings, like atrial fibrillation (AF), acute coronary syndrome (ACS), acute venous thromboembolism (VTE), and in patients undergoing invasive cardiac procedures. More than 6 million patients in the United States receive long-term anticoagulation therapy for the prevention of thromboembolism due to AF, placement of a mechanical heart-valve prosthesis, or VTE.1 For more than 60 years, until 2009, warfarin and other vitamin K antagonists were the only class of oral anticoagulants (OAC) available. Although these drugs are highly effective in prevention of TE, their use is limited by a narrow therapeutic index that necessitates frequent monitoring and dose adjustments. This results in substantial risk and inconvenience, leading to inadequate anticoagulant prophylaxis. Recently some new OAC have been marketed which are effective, easier to use and has less side effects. Dabigatran is a new oral thrombin inhibitor and Rivaroxaban, Apixaban and Edoxaban are oral factor Xa inhibitors. This review outlines why these new OACs were essential and describes in detail about these new drugs. J Bangladesh Coll Phys Surg 2019; 37(3): 135-150

Rock joints play an important role in the behavior of rock masses under normal and shear loading conditions. Numerical simulation of the behavior of jointed rock masses is not an easy task due to complexities involved in the problem such as joint roughness, joint shear strength, hardening and softening phenomenon and mesh dependency. In this study for modeling purposes, a visco-plastic multilaminate model considering hardening and softening effects has been employed. For providing the necessary data for numerical simulation, a series of laboratory experiments have been carried out on regular tooth-shape asperities made by gypsum, under constant normal load conditions. Shear stress–shear displacement and normal displacement–shear displacement of artificial joint specimens are simulated using the proposed numerical model at constant normal load condition (CNL). The results indicate the capability of the model for simulating rock joints behavior in both strength and deformation field. Although the numerical model has been developed for simulating the behavior of artificial joints, the concept of the method can also be used for natural rock joints.

The continuous power scheme was the choice of many researchers towards power allocation. However, continuous power application is not very suitable following hardware complexity. For this discrete power is efficient, especially in cellular systems as it could reduce the feedback rate. On the other hand, receiver mobility implies transmission thresholds and power level alternation determination which leads to reduction in system's spectral efficiency (SE). Consequently, a method based on adaptive modulation (AM) has been introduced and some power discrete levels while all information of channel state wasn't considered. Computer results highlight that the proposed scheme provides better efficiency in comparison to other adaptation schemes but with less feedback rate.

β-lactam and fluoroquinolone antibiotics are usually used for the treatment of urinary tract infections (UTIs). The aim of this study was to determine the prevalence of plasmid-mediated quinolone resistance (PMQR) and extended spectrum β-lactamases (ESBLs) in isolated from UTIs. Two hundred and nineteen samples of isolated from UTIs were collected in the Northwest of Iran. Antimicrobial susceptibility testing was determined by the disk diffusion method. ESBLs were detected by the double-disk test. ESBL and PMQR-encoding genes were screened using the polymerase chain reaction. The rate of resistance to moxifloxacin, nalidixic acid, gatifloxacin, ofloxacin, ciprofloxacin, and levofloxacin in ESBL-producing isolates was 89.3%, 88%, 84%, 80%, 78.7%, and 73.3%, respectively. PMQR-producing isolates were identified in 67 samples (89.1%). The most prevalent PMQR genes were ' 120 (68.6%) followed by 72 (41.1%), 59 (33.7%), 36 (20.6%), 33 (18.9%), 19 (10.9%), 13 (7.4 %), 10 (5.7%), and 9 (5.1%). There was a strong association between PMQR genes and and and other ESBL genes. High resistance rates were detected to quinolones among ESBL-producing isolates from UTIs. There is a high prevalence of PMQR genes in in Azerbaijan and Iran, and the most common PMQR is ' . There is a significant association between PMQR and ESBL-producing isolates.

The adsorption of asphaltene on the rock surface and the changes in its wettability are very relevant issues in flow assurance and oil recovery studies, and for carbonate reservoirs, they are even more important. During microbial enhanced oil recovery (MEOR) processes, wettability alteration is considered a crucial mechanism leading to improved oil recovery. Therefore, it is essential to understand the mechanisms of surface wettability changes by bacteria and biosurfactants and find new and reliable methods to prevent asphaltene adsorption. Hence, the main aim of this research was to investigate the effect of a mixture of thiobacillus thiooxidans and thiobacillus ferooxidans microorganisms with an optimum effective temperature of around 30 °C (referred to as mesophilic bacteria), as well as a mixture of two moderate thermophiles Sulfobacillus thermosulfidooxidans for operating temperatures around 50 °C (referred to as moderately thermophilic bacteria) on the adsorption of asphaltene samples isolated from two different crude oils onto main reservoir minerals (i.e., quartz and dolomite). The results indicated that after two weeks of mineral aging in moderate thermophilic bacteria, the adsorption of asphaltene on both minerals increased between 180 and 290%. Fourier-transform infrared spectroscopy (FTIR) analysis for quartz and dolomite samples demonstrated that after aging in bacterial solution, bonds related to the adsorption of bacterial cells and biosurfactant production appear, which are the main factors of change in wettability. Alteration in wettability towards hydrophilicity expands hydrogen bonds on the surface, thus improving asphaltene adsorption due to polar interaction. Asphaltene 1 changed the contact angle of dolomite from 53.85° to 90.51° and asphaltene 2 from 53.85° to 100.41°. However, both strains of bacteria caused a strong water-wetting effect on the dolomite rock samples. The influence of moderate thermophilic bacteria on surface wettability is more significant than that of mesophilic bacteria, which may be caused by the high protein content of these bacteria, which expands hydrogen bonding with the surface. Adsorption of asphaltenes on dolomite rocks previously aged with bacteria showed that the wetted rock samples retained their water-wet state. This study highlights the dual impact of the used microorganisms. On one hand, they significantly reduce contact angles and shift wettability towards a strongly water-wet condition, a crucial positive factor for MEOR. On the other hand, these microorganisms can elevate the adsorption of asphaltenes on reservoir rock minerals, posing a potential challenge in the form of formation damage, particularly in low-permeability reservoirs.

Carbon dioxide (CO 2 ) is the main greenhouse gas that drives global warming, climate change, and other environmental issues. CO 2 absorption using amine solvents stands out as one of the most well-known industrial technologies of CO 2 capture. However, accurate prediction of CO 2 absorption in aqueous amine solutions under different operating conditions is crucial for designing an efficient amine scrubbing system in power plants. In this work, CO 2 solubility in aqueous piperazine (PZ) solutions was modeled using 517 experimental data points covering a temperature range of 298 to 373 K, PZ concentration of 0.1 to 6.2 mol/L (M), and CO 2 partial pressure of 0.03 to 7399 kPa. To this end, four robust machine learning algorithms, including gradient boosting with categorical features support (CatBoost), light gradient boosting machine (LightGBM), extreme gradient boosting (XGBoost), and adaptive boosting decision trees (AdaBoost-DT) were utilized. Among the developed models, the CatBoost model presented the highest accuracy with an overall determination coefficient (R 2 ) of 0.9953 and an average absolute relative error of 2.36%. Sensitivity analysis revealed that CO 2 partial pressure had the greatest influence on CO 2 absorption in aqueous PZ solutions, followed by PZ concentration and temperature. Moreover, CO 2 partial pressure positively influenced CO 2 absorption in aqueous PZ solutions, while PZ concentration and temperature exhibited negative effects. Finally, the leverage technique indicated that both the experimental data bank used for modeling and the model’s estimates were statistically acceptable and valid showing only 8 points (∼1.5% of total data) as possible suspected data.

Asphaltene precipitation and its adsorption on different surfaces are challenging topics in the upstream and downstream of the oil industries and the environment. In this research, the phenomenon of asphaltenes adsorption in the presence and absence of water on the surface of magnetite, hematite, calcite, and dolomite nanoparticles (NPs) was investigated. Five asphaltenes of different origins, four NPs as adsorbents and Persian Gulf water were used for three-phase (asphaltene/toluene solution + NPs + water) experiments. Characterization of asphaltenes and NPs was performed using Fourier transform infrared spectroscopic (FTIR), dynamic light scattering (DLS), elemental analysis, and field emission scanning electron microscopy (FESEM). Adsorption experiments were performed in two- (asphaltene/toluene solution + NPs) and three-phase systems. The results showed that the most effective parameters for asphaltene adsorption onto these NPs are the asphaltene composition, namely nitrogen content, and the aromaticity of asphaltenes. The significant effects of these parameters were also confirmed by the relevancy factor function as a sensitivity analysis. In the competition of asphaltene adsorption capacity by NPs, iron oxide NPs had the highest adsorption (Magnetite NPs > Hematite NPs > Calcite NPs > Dolomite NPs). From the results of the experiments in the presence of water phase, it could be pointed out that the asphaltenes adsorption onto the NPs was accompanied by a decrease compared to the experiments in the absence of water. The modeling also showed that physical adsorption has a significant contribution to the asphaltenes adsorption on the surface of iron oxides and lime NPs. The results of this research can assist in a better understanding of the asphaltene adsorption phenomenon and the role of iron oxide and lime NPs in solving this problem.

Magnetic separation is a common procedure for the enrichment of magnetic iron ores. Davis tube (DT) test is a standard laboratory technique used to determine the optimum magnetic recovery of iron ore using wet low-intensity magnetic separators. However, the DT test is time-consuming and labour-intensive. In this study, based on the results of DT-tests, generalized regression (GRNN) and radial basis function (RBF) neural networks were developed to predict iron recovery through the Fe and FeO content of the feed. First, the DT tests were performed on 613 iron ore samples with varying Fe and FeO content. Then, neural networks were used to model the iron recovery from the DT test, using the Fe and FeO content of the feed as input data. The modeling results showed that GRNN is a better model for predicting iron recovery. The main statistical metrics indicated that GRNN has AAPRE, RMSE, and R 2 values of 3.929%, 2.804, and 0.976 respectively for a total of 613 data points. Moreover, sensitivity analysis demonstrated that iron recovery is directly influenced by both Fe and FeO contents, with FeO content having a more pronounced effect. Finally, Leverage analysis showed that GRNN is highly reliable for predicting iron recovery, with only 2.77% of data points flagged as suspicious based on outlier estimation.

Geothermal energy, oil industry, and underground gas storage technology require deep drilling. Although oil-based drilling fluids have been widely used, they cause environmental issues. Environmentally friendly Aphronic fluid has emerged as an alternative to oil-based drilling fluid. Despite various investigations on Aphron’s performance, the effect of temperature has not yet been comprehensively studied. In this study, Aphronic fluid was developed with xanthan gum (XG) as a polymer and alpha-olefin sulfonate (AOS) as a surfactant. Furthermore, another Aphronic fluid was developed with xanthan gum (XG) as a polymer and sodium dodecyl sulfate (SDS) as a surfactant. This study evaluates their rheological properties, including shear rate (ranging from 0.1 to 10 s − 1 ), across a range of temperatures (25 ℃, 49 ℃, 71 ℃, and 93 ℃). Stability testing was conducted at ambient temperature, and rheology tests were performed at various temperatures. It was found that the rheological properties decrease as the temperature increases. An increase in the temperature and shear rate decreases the viscosity of the drilling fluid. AOS demonstrated higher stability and less reduction in rheological properties at elevated temperatures than SDS. This difference can be attributed to SDS’s tendency to denature the XG polymer, leading to a notable decrease in viscosity. Maintaining viscosity is crucial for fluid stability and enhancement of rheological properties. Moreover, the best stability was achieved at 1.5 times the critical micelle concentration (CMC). This behavior is consistent with the Gibbs elasticity theory, indicating that the optimal concentration for both AOS and SDS surfactants is 1.5 times the CMC. Deviation from this optimal concentration resulted in decreased system stability. The determination of the CMC value showed a broader region rather than a singular point, potentially confirming the Gibbs-Marangoni theory. The implications of this research underscore the importance of selecting the appropriate Aphronic fluid formula for drilling operations to ensure stability and rheological properties conducive to overcoming reservoir pressure and accurately facilitating the cutting transfer process. This research highlights the need to choose the right Aphronic fluid formula for drilling. Using the right formula helps in drilling to ensure stability and rheological properties conducive to overcoming reservoir pressure and accurately facilitating the cutting transfer process.