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991.
Abbas Khan. Dong-Qing Wei Kafila Kousar Jehad Abubaker Sajjad Ahmad Javaid Ali Fahd Al-Mulla Syed Shujait Ali N. Nizam-Uddin Abrar Mohammad Sayaf Anwar Mohammad 《Chembiochem : a European journal of chemical biology》2021,22(16):2641-2649
The evolution of new SARS-CoV-2 variants around the globe has made the COVID-19 pandemic more worrisome, further pressuring the health care system and immunity. Novel variations that are unique to the receptor-binding motif (RBM) of the receptor-binding domain (RBD) spike glycoprotein, i. e. L452R-E484Q, may play a different role in the B.1.617 (also known as G/452R.V3) variant's pathogenicity and better survival compared to the wild type. Therefore, a thorough analysis is needed to understand the impact of these mutations on binding with host receptor (RBD) and to guide new therapeutics development. In this study, we used structural and biomolecular simulation techniques to explore the impact of specific mutations (L452R-E484Q) in the B.1.617 variant on the binding of RBD to the host receptor ACE2. Our analysis revealed that the B.1.617 variant possesses different dynamic behaviours by altering dynamic-stability, residual flexibility and structural compactness. Moreover, the new variant had altered the bonding network and structural-dynamics properties significantly. MM/GBSA technique was used, which further established the binding differences between the wild type and B.1.617 variant. In conclusion, this study provides a strong impetus to develop novel drugs against the new SARS-CoV-2 variants. 相似文献
992.
Solomon Hanson Duntu Francis Tetteh Iftikhar Ahmad Mohammad Islam Solomon Boakye-Yiadom 《Ceramics International》2021,47(1):367-380
The onset of hybrid alumina-based composites, which combines two or more nano-particles within the alumina matrix has already shown promising improvements in the matrix material. However, variations in mechanical properties including the optimum compositions that give improved properties faced with the development of alumina-based composites require further studies to understand the underlying mechanisms and synergistic effects of the nano-particle additions on the alumina matrix. In the current study, the structure and properties of Al?O?-graphene (0.5 wt%) and Al?O?–ZrO? (4 wt% and 10 wt%) composites fabricated via hot-pressing was studied as a baseline for multiple combinations. Even though the addition of 10 wt%ZrO? resulted in a 23% reduction in the grain size of the alumina matrix, the 4 wt%ZrO? addition resulted in a 14% increase in grain size as compared to the parent alumina matrix. X-ray diffraction analysis revealed that there was approximately 85% monoclinic (m-ZrO2) vs. 15% tetragonal (t-ZrO2) crystal structures in the A4ZrO? sample whilst the A10ZrO? had approximately 93% m-ZrO2 vs. 7% t-ZrO2. The high-volume fraction of the monoclinic crystal structures in the A10ZrO? accounts for the induced microcracks in the sample since the transition from the ductile-tetragonal to brittle-monoclinic is associated with the exertion of compressive stresses on the alumina matrix by the associated elastic volume expansion of m-ZrO2. Also, the addition of 0.5 wt%graphene resulted in about 37% reduction in the grain size of the alumina matrix, and approximately 10% increase in hardness as a result of the distribution of graphene along the grain boundaries of the parent alumina matrix, which restricts grain coalescence and growth during processing. Furthermore, an increase up to 115% and 164% were observed in the fracture toughness (KIC) with the inclusion of 0.5 wt%graphene and 10 wt%ZrO? respectively, which was primarily ascribed to the fine-grained microstructures and toughening mechanisms of the intergranular graphene and ZrO? particles. 相似文献
993.
Zhale Gholampour Shamami Mir Saeed Seyed Dorraji Seyyedeh Fatemeh Hosseini Mohammad Hossein Rasoulifard Ismael Hajimiri Alireza Amani-Ghadim 《Ceramics International》2021,47(15):21334-21342
The current paper focuses on synthesizing a high-efficiency microwave absorber via incorporating the nanofillers of graphene oxide-polyaniline (GO-PANI), barium-strontium titanate (BST), and soft-hard ferrite within the polyester matrix. The nanocomposite magnets of (Ba0.5Sr0.5Fe12O19)1-x hard/(CoFe2O4)x soft (x = 0.2, 0.5, and 0.8) were prepared using sol-gel auto-combustion method. The GO-PANI and BST were successfully synthesized by in situ polymerization and improved polymerization, respectively. The phase structure, chemical structure, morphology, and microwave absorption properties of the synthesized nanocomposites were characterized by X-ray diffractometer (XRD), Fourier-transform infrared spectroscopy (FT-IR), and scanning electron microscope (SEM), vector network analyzer (VNA) techniques, respectively. The results showed that the synergistic effects of the combination of dielectric (BST), conductive (GO-PANI), and magnetic materials (hard-soft ferrites) provided the reflection loss values of less than ?20 dB (>99% absorption) in the X-band region. The minimum reflection loss of ?35 dB (>99.99% absorption) was obtained by the optimal formulation including (Ba0.5Sr0.5Fe12O19)0.2 (CoFe2O4)0.8, and the weight ratio of 1: 2 for both BST/soft-hard ferrite and hard-soft ferrite + BST/GO-PANI with the thickness of 1 mm. According to the results, the thickness factor plays a key role in improving the impedance matching. Consequently, the proposed nanocomposite can be employed as a novel kind of microwave absorbers with good impendence matching and high absorption. 相似文献
994.
The weeping phenomenon was investigated using some experimental tests and a numerical model. The tests were performed within a 1.22‐m‐diameter pilot‐scale column including two chimney trays and two Nye test trays with an air‐water system. The rates of weeping were measured in the Nye trays with two heights of the weir and a hole area of 5 %. Moreover, the weeping rates in the outlet and inlet halves of the Nye tray and the total weeping rate were calculated. In the next step, an Eulerian‐Eulerian computational fluid dynamics (CFD) technique was used. The results show good agreement between the attained CFD findings and the experimental data. 相似文献
995.
Heidarizadeh Yousef Lajevardi Seyed Hamid Sharifipour Mohammad Kamalian Mohsen 《Bulletin of Engineering Geology and the Environment》2021,80(3):2523-2534
Bulletin of Engineering Geology and the Environment - The accurate and efficient modification of the static and dynamic properties of problematic soils is a primary concern in geotechnical... 相似文献
996.
Alireza Ramezani Hossein Abdizadeh Mohammad Reza Golobostanfard 《Ceramics International》2021,47(13):17895-17906
In this work, the BaTiO3 and SrTiO3 thin films as well as BaTiO3/SrTiO3 lamellar composites are synthesized via sol-gel spin-coating method. The formation of corresponding phases from their sols is investigated by virtue of X-ray diffraction on their powders, which confirms the formation of tetragonal structure for BaTiO3, but cubic structure for SrTiO3. The field emission scanning electron microscopy images show that crack-free films with different morphologies are formed in each sample. Likewise, by changing periodicity of the samples, the morphology of the composite samples is changed. As the number of layers increases from 1 to 20, the band gap reduces from 4.38 eV to 4.10 eV for BaTiO3 samples and from 4.13 eV to 3.80 eV for SrTiO3 samples confirmed by UV–Vis spectra. The band gap of periodicity = 1 sample is higher than that of BaTiO3, while band gaps of periodicity = 2 and 5 composites mount between those of BaTiO3 and SrTiO3. In addition, the refractive indices of multi-stacked composites are about 0.2 lesser than refractive indices of BaTiO3 sample in high wavelengths. The periodicity dependence of optical frequency dielectric constant, dielectric loss, impedance, Urbach tail, extinction coefficient, and electric modulus of multi-stacked composites are also studied. 相似文献
997.
Hamdy Mohamed S. Al-Zaqri Nabil Sahlabji Taher Eissa Murad Haija Mohammad Abu Alhanash Abdullah M. Alsalme Ali Alharthi Fahad A. Abboud Mohamed 《Catalysis Letters》2021,151(6):1612-1622
Catalysis Letters - To avoid the aggregation problem and activity loss of nickel oxide (NiO) nanoparticles (NPs) in organic reactions, NiO NPs were incorporated into TUD-1 mesoporous material.... 相似文献
998.
Koosha Fereshteh Farsangi Zohreh Jomeh Samadian Hadi Amini Seyed Mohammad 《Journal of Porous Materials》2021,28(6):1961-1968
Journal of Porous Materials - The development of theranostic nanostructures is one of the most advanced branches of pharmaceutical and medical sciences in the world today. Due to the unique... 相似文献
999.
Shyfuddin Ahmed Boubakari Ibrahimou Shirmin Bintay Kader Muhammad Ashique Haider Chowdhury Habibul Ahsan Mohammad Yunus 《Indoor air》2021,31(6):2167-2175
Despite significant investment, childhood malnutrition continues to be a significant public health problem especially in least developed countries. The aim of this study was to find association between household biomass fuel (BMF) use and childhood malnutrition in Bangladesh using data from Demographic and Health Survey 2011. We included a total 6891 children under 5 years of age in the analysis. The prevalence of wasting, underweight, and stunting from BMF using household was 16.1% (n = 997; 95%CI, 15.1–17.3), 39.0% (n = 2399; 95%CI, 37.1–40.9), and 43.3% (n = 2620; 95%CI, 41.6–45.1), respectively. Underweight and stunting were significantly higher among children from households using BMF compared with the children from CF using households (underweight, biomass vs clean fuel: 39.0% vs. 23.5%, p < 0.001; stunting, biomass vs clean fuel: 43.3 vs. 31.5%, p < 0.001). The use of BMF in the household was significantly associated with underweight (OR = 1.38; 95%CI: 1.10–1.73) and stunting (OR = 1.58; 95%CI: 1.18–1.98) among children <5 years of age after adjusting possible confounders in mixed effect logistic regression analysis. This study found a significant association between chronic childhood malnutrition and household BMF use which is indicating possible alternative risk factor for malnutrition. Further prospective research is required to explore the mechanism of how BMF use results in chronic malnutrition. 相似文献
1000.
Mohammad Mojtaba Sadeghi Mohamed F. Salama Yusuf A. Hannun 《International journal of molecular sciences》2021,22(11)
Driver-directed therapeutics have revolutionized cancer treatment, presenting similar or better efficacy compared to traditional chemotherapy and substantially improving quality of life. Despite significant advances, targeted therapy is greatly limited by resistance acquisition, which emerges in nearly all patients receiving treatment. As a result, identifying the molecular modulators of resistance is of great interest. Recent work has implicated protein kinase C (PKC) isozymes as mediators of drug resistance in non-small cell lung cancer (NSCLC). Importantly, previous findings on PKC have implicated this family of enzymes in both tumor-promotive and tumor-suppressive biology in various tissues. Here, we review the biological role of PKC isozymes in NSCLC through extensive analysis of cell-line-based studies to better understand the rationale for PKC inhibition. PKC isoforms α, ε, η, ι, ζ upregulation has been reported in lung cancer, and overexpression correlates with worse prognosis in NSCLC patients. Most importantly, PKC isozymes have been established as mediators of resistance to tyrosine kinase inhibitors in NSCLC. Unfortunately, however, PKC-directed therapeutics have yielded unsatisfactory results, likely due to a lack of specific evaluation for PKC. To achieve satisfactory results in clinical trials, predictive biomarkers of PKC activity must be established and screened for prior to patient enrollment. Furthermore, tandem inhibition of PKC and molecular drivers may be a potential therapeutic strategy to prevent the emergence of resistance in NSCLC. 相似文献