Revisiting scalar field cosmology with Λ(t)\Lambda(t) in f(R,T)f(R,T) gravity

Two scalar field cosmological models in $f(R,T)$ gravity with cosmic transit and varying cosmological constant have been investigated. The time-dependent cosmological constant $\Lambda(t)$ is positive and tends to a very small value at the present epoch. The scalar field pressure $p_{\phi}$ shows a sign flipping for normal scalar field. For the phantom field, the scalar potential $V(\phi)$ is negative and the energy density $\rho_{\phi}=E_k+V$ takes negative values when the equation of state parameter $\omega_{\phi}<-1$. While the weak energy condition WEC implies that the total energy density $\rho=\sum_i\rho_i\geq 0$, we still can have a negative $\rho$ term as long as the total $\rho$ is positive. In the current work we argue that the WEC, $\rho=\sum_i \rho_i \geq 0$ and $p_i+\rho_i \geq 0$, is not violated. For a scalar field $\phi$, The condition $\rho_{\phi}+p_{\phi}=\rho_{\phi} (1+\omega_{\phi})=2E_k\geq 0$ allows for $\rho_{\phi}<0$ if $\omega_{\phi}<-1$. The cosmology in both models has been probed using a given function $a(t)$ deduced from the desired cosmic behavior which is the opposite of the conventional viewpoint

Dynamic strategy based fast decomposed GA coordinated with FACTS devices to enhance the optimal power flow

International audienceUnder critical situation the main preoccupation of expert engineers is to assure power system security and to deliver power to the consumer within the desired index power quality. The total generation cost taken as a secondary strategy. This paper presents an efficient decomposed GA to enhance the solution of the optimal power flow (OPF) with non-smooth cost function and under severe loading conditions. At the decomposed stage the length of the original chromosome is reduced successively and adapted to the topology of the new partition. Two sub problems are proposed to coordinate the OPF problem under different loading conditions: the first sub problem related to the active power planning under different loading factor to minimize the total fuel cost, and the second sub problem is a reactive power planning designed based in practical rules to make fine corrections to the voltage deviation and reactive power violation using a specified number of shunt dynamic compensators named Static Var Compensators (SVC). To validate the robustness of the proposed approach, the proposed algorithm tested on IEEE 30-Bus, 26- Bus and IEEE 118-Bus under different loading conditions and compared with global optimization methods (GA, EGA, FGA, PSO, MTS, MDE and ACO) and with two robust simulation packages: PSAT and MATPOWER. The results show that the proposed approach can converge to the near solution and obtain a competitive solution at critical situation and with a reasonable time

Fuzzy Controlled Parallel PSO to Solving Large Practical Economic Dispatch

International audienceThis paper proposes a version of fuzzy controlled parallel particle swarm optimization approach based decomposed network (FCP-PSO) to solve large nonconvex economic dispatch problems. The proposed approach combines practical experience extracted from global database formulated in fuzzy rules to adjust dynamically the three parameters associated to PSO mechanism search. The adaptive PSO executed in parallel based in decomposed network procedure as a local search to explore the search space very effectively. The robustness of the proposed modified PSO tested on 40 generating units with prohibited zones and compared with recent hybrid global optimization methods. The results show that the proposed approach can converge to the near solution and obtain a competitive solution with a reasonable time compared with recent previous approaches

Synthesis, antibacterial, antibiofilm evaluation and molecular docking studies of 3-methyl- 2-propyl-2H-[1,2,4]triazolo[4,3b] [1,2,4,6]thiatriazine-1,1-dioxide

ABSTRACT. In the current study, a simple method for the synthesis of 3-methyl-2-propyl-2H-[1,2,4]triazolo[4,3b][1,2,4,6]thiatriazine-1,1-dioxide (2) was carried out. In the presence of pyridine, a reaction between amidine (1) and sulfuryl chloride occurs. FTIR spectroscopy, 1H and 13C NMR, mass spectra, and elemental analysis were utilized in order to verify the structure of a novel synthetic molecule. The antibacterial activities of compound (2) were tested against eight pathogenic bacteria and the minimum inhibitory concentration as well as minimum bactericidal concentration were determined. Moreover, the possible antibiofilm effect of compound (2) was evaluated. Molecular docking was investigated to determine the interaction between compound (2) and eight crystal structures of bacterial and yeast proteins associated with virulence activity and antimicrobial resistance. Our results showed that the new 3-methyl-2-propyl-2H-[1,2,4]triazolo[4,3b][1,2,4,6]thiatriazine-1,1-dioxide (2) compound has a moderate antibacterial activity toward the selected pathogenic bacteria. The obtained MICs varied from 32 to 512 µg/mL being the lowest values attributed to Staphylococcus epidermidis ATCC 14990 and Streptococcus mutans ATCC 25175 (MIC = 32 µg/mL).We noted also that heterocyclic compound (2) may inhibit bacterial biofilm formation at concentration depend manner with a lowest value obtained against S.mutans ATCC 25175 (BIC50&nbsp;= 490 µg/mL). Molecular docking showed a promising inhibitory activity of compound (2) on TetM-mediated tetracycline resistance (3J25) and Staphylococcus aureus gyrase (3G7B) with lower binding energy compared to the other target proteins. &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; KEY WORDS: Synthesis, Thiatriazine-1,1-dioxide, Antibacterial, Antibiofilm, Molecular docking Bull. Chem. Soc. Ethiop. 2022, 36(1), 109-117.&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; DOI: https://dx.doi.org/10.4314/bcse.v36i1.10&nbsp; &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp

Antibacterial and resistance-modifying activities of thymoquinone against oral pathogens

<p>Abstract</p> <p>Background</p> <p>The presence of resistant bacteria in the oral cavity can be the major cause of dental antibiotic prophylaxis failure. Multidrug efflux has been described for many organisms, including bacteria and fungi as part of their drugs resistance strategy. The discovery of a new efflux pump inhibitor could extend the useful lifetime of some antibiotics.</p> <p>Methods</p> <p>In this study, the MICs of thymoquinone (TQ), tetracycline and benzalkonium chloride (BC) were determined in absence and in presence of a sub-MIC doses of thymoquinone (1/2 MIC). In addition the 4,6-diamidino-2-phenylindole (DAPI) efflux assay was carried out to determine the effect of TQ on DAPI cells accumulation.</p> <p>Results</p> <p>TQ induced a selective antimicrobial activity. Its synergic effect resulted in at least a 4-fold potentiation of the tested antibiotics and antiseptic. In addition, TQ inhibited the DAPI efflux activity in a concentration-dependent manner. The rate of DAPI accumulation in clinical isolates was enhanced with TQ (0 to 200 μg/ml). There is also a decrease in loss of DAPI from bacteria in the presence of TQ. The concentration causing 50% of DAPI efflux inhibition after 15 minutes was approximately 59 μg/ml for <it>Pseudomonas aeroginosa </it>and 100 μg/ml and <it>Staphylococcus aureus </it>respectively.</p> <p>Conclusions</p> <p>TQ possesses a selective antibacterial activity against oral bacteria. It is therefore suggested that TQ could be used as a source of natural products with resistance-modifying activity. Further investigation is needed to assess their clinical relevance.</p

Numerical analysis of reducing tunneling effect on viaduct piles foundation by jet grouted wall

Purpose. The target of this study is divided into two parts. The first part is concerned with capability of numerical model to simulate the tunneling process. The second part is related to studying the interaction mechanism between the tunnel, protection technique, and soil. This study themes are investigated by analyzing different protection technique configuration, considering different stiffness of the grouted wall, and applying different interface coefficient between the wall and the soil. Methods. The method used in this study to check the accuracy of the proposed numerical model is 4-D ABAQUS program. The typical excavation of a tunnel is simulated step by step with an assumed rate of tunnel advancement (0.5 to 1.5 m/hr). The soil material utilized in this model is elastic perfectly plastic (the Mohr-Сoulomb criterion), while elastic material is modeled as solid element (S4R) adopted for lining, grouting, filling gaps, shielding, constructing piles, and jet grouted wall. Findings. Results showed that the closer jet grouting to the tunnel with embedded length of 1.5 times tunnel diameter, the better effect on reducing the lateral deformation and bending moment generated on piles. Otherwise, increasing wall thickness more than double grouted column diameter would not affect its shielding efficiency. Furthermore, either increasing or decreasing friction coefficient even if rough between the grouted wall and soil had no effect on the pile behavior. Additionally, applying Mohr-Coulomb criteria for grouted wall with high stiffness allowed realistic response of the pile group. Originality. Capability of the proposed model is verified by back analysis of Changsha Subway Line 1 project, where the shield tunnel would be constructed near existing pile groups of L off-ramp of the Xinzhong Road viaduct. Practical implications. Increasing grouted wall configuration is more effective than mechanical properties or its interface coefficient with surrounded soil in mitigating tunneling effect on nearby piles.Мета. Виконати чисельне моделювання опису процесу проходки тунелю, а також вивчення механізмів взаємодії між тунелем, способом кріплення та підошвою за допомогою аналізу різних конфігурацій кріплення з урахуванням різної міцності залитої цементним розчином стіни й застосування різних коефіцієнтів межі розділу між стіною і підошвою. Методика. Для перевірки точності запропонованої чисельної моделі використовувалася програма 4-D ABAQUS. Проходка тунелю моделюється покроково при передбачуваній швидкість проходки від 0.5 до 1.5 м/год. Дана модель розглядає матеріал підошви як еластичний ідеально пластичний (за критерієм Мора-Кулона). Еластичний матеріал представлений в моделі як тверда речовина (S4R), що використовується для оброблення, цементування, заповнення пустот, щитової проходки, спорудження свай та залитих струменевим розчином стінок. Результати. Результати дослідження свідчать про те, що чим ближче розташована установка струменевої цементації до тунелю, довжина якого в півтора рази більше його діаметра, тим більший вплив вона чинить на зменшення бічних деформацій і згинальні моменти свай. Встановлено, що збільшення товщини стінок до величини, що вдвічі перевищує діаметр залитих струменевим розчином свай, не впливає на їх захисну здатність. Крім того, ні збільшення, ні зменшення коефіцієнта тертя між залитою цементним розчином стіною і підошвою не чинить істотного впливу на поведінку свай. Застосування критерію Мора-Кулона для високоміцної зацементованої струменевим розчином стіни дозволяє реалістично оцінити реакцію групи свай. Наукова новизна. Надійність даної моделі підтверджена зворотним аналізом в рамках проекту 1-й лінії метро Чанши, згідно з яким тунель буде побудований методом щитової проходки навколо існуючих груп опор на L з’їзді з віадука траси Ксінжонг. Практична значимість. Зміцнена структура зацементованої стінки дозволяє зменшити вплив проходки тунелю на сваї та підвищити надійність і стійкість споруди.Цель. Выполнить численное моделирование описания процесса проходки тоннеля, а также изучение механизмов взаимодействия между тоннелем, способом крепления и грунтом посредством анализа разных конфигураций крепления с учетом различной прочности залитой цементным раствором стены и применения различных коэффициентов границы раздела между стеной и почвой. Методика. Для проверки точности предложенной численной модели использовалась программа 4-D ABAQUS. Проходка тоннеля моделируется пошагово при предполагаемой скорости проходки от 0.5 до 1.5 м/час. Данная модель рассматривает материал грунта как эластичный идеально пластичный (по критерию Мора-Кулона). Эластичный материал представлен в модели как твердое вещество (S4R), используемое для обделки, цементирования, заполнения пустот, щитовой проходки, сооружения свай и залитых струйным раствором стенок. Результаты. Результаты исследования свидетельствуют о том, что чем ближе расположена установка струйной цементации к тоннелю, длина которого в полтора раза больше его диаметра, тем большее влияние она оказывает на уменьшение боковых деформаций и сгибающего момента свай. Установлено, что увеличение толщины стенок до величины, вдвое превышающей диаметр залитых струйным раствором свай, не влияет на их защитную способность. Кроме того, ни увеличение, ни уменьшение коэффициента трения между залитой цементным раствором стеной и грунтом не оказывает существенного влияния на поведение свай. Применение критерия Мора-Кулона для высокопрочной зацементированной струйным раствором стены позволяет реалистично оценить ответную реакцию группы свай. Научная новизна. Надежность данной модели подтверждена обратным анализом в рамках проекта 1-й линии метро Чанши, согласно которому тоннель будет построен методом щитовой проходки вокруг существующих групп опор на L съезде с виадука трассы Ксинжонг. Практическая значимость. Упрочненная структура зацементированной стенки позволяет уменьшить воздействия проходки тоннеля на сваи и повысить надежность и устойчивость сооружения.The authors would like to thank the anonymous reviewers and the editor for their valuable comments

Validity of sphenoid ostium in relation to posterior wall of maxillary sinus by computed tomography

Background: Sphenoid sinus is the most inaccessible paranasal sinus, enclosed within the sphenoid bone and intimately related to numerous vital neural and vascular structures. Anatomic variation of the sphenoid sinus is well documented and may complicate surgery in such a place.Objective: To assess the reliability of preoperative computed tomography (CT) in determination of the distance between the posterior wall of maxillary sinus (PWMS) and the sphenoid sinus ostium (SSO) in the coronal plane.Patients and methods: This was a prospective study of the distance between the SSO and the PWMS in the coronal plane, which was measured both radiologically in preoperative CT and intraoperatively during endoscopic sinus surgery for patients in need for middle meatal antrostomy and sphenoid sinusotomy at the same side. Distances obtained by both techniques have been tested for the degree of correlation. Number of the included patients was 25.Results: Forty four nasal sides were included in the study. The mean distance between the sphenoid sinus ostium and posterior wall of maxillary sinus in the coronal plane was 6.6 ± 1.8 mm when measured by preoperative CT and 6.9 ± 1.9 mm when measured directly during surgery. No significant difference was found between the mean distances measured by both techniques (p = 0.246) with good agreement between them (r = 0.864).Conclusion: Preoperative CT may be a reliable tool to preoperatively determine the difference in depth between the PWMS and the SSO