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A robust method of hazardous metal ion removal from an aqueous environment involves the use of chelating agents, such as ethylenediaminetetraacetic acid (EDTA). Here, we focus on mercury (Hg2+) uptake by EDTA using both molecular dynamics and density functional theory simulations. Our results indicate that the deprotonation of the EDTA carboxylate groups improves the localization of negative charge on the deprotonated sites. This mechanism facilitates charge transfer between the metal ions and EDTA, and provides a stronger and more stable EDTA–Hg2+ complex formation improving the efficiency of the chelation process. The best metal removal conditions are achieved using the fully deprotonated form of EDTA, which naturally occurs at pH levels above 3. [ABSTRACT FROM AUTHOR]

Removal of CO2 from air is one of the key human challenges in battling global warming. SIFSIX-3-Cu is a promising metal–organic framework (MOF) suggested for carbon capture even at low CO2 concentrations. However, the impact of humidity on its performance in direct air capture (DAC) is poorly understood. To evaluate the MOF performance for DAC application under humid conditions, we investigate the adsorption of H2O, CO2, and N2 using density functional theory (DFT), grand canonical Monte Carlo (GCMC), and molecular dynamics (MD) simulations. The simulation results show a higher tendency of SIFSIX-3-Cu towards H2O adsorption rather than CO2 (and N2). The results agree with the adsorption isotherms for the pure compounds from the Sips model. The extended Sips model shows 1.34 mmol g−1 CO2 adsorption at the atmospheric pressure and 298 K for the CO2/N2 mixture containing 400 ppm CO2, and low CO2 adsorption (less than 0.75 mmol g−1) at a low relative humidity (RH) of 20%. This finding highlights the efficiency of SIFSIX-3-Cu for DAC in dry air and the negative impact of humidity on the CO2 selective adsorption. Therefore, we suggest to consider the impairing of humidity effects when designing a SIFSIX-3-Cu-based CO2 separation process and removal of any water vapor before introduction of the air to SIFSIX-3-Cu. [ABSTRACT FROM AUTHOR]

Some earlier studies reported higher risk of COVID-19 mortality in patients with vitamin D deficiency, while some others failed to find such as association. Due to inconsistences between earlier meta-analyses and needs for an updated study, we conducted current systematic review and meta-analysis on the association between vitamin D status and risk of COVID-19 in-hospital mortality among observational studies. We searched PubMed, Scopus and Web of Science up to 27 July 2021. We conduct our systematic review and meta-analysis in according to PRISM statement. Two authors independently screened studies and extracted data from the relevant ones. All types of observational studies about the association between vitamin D status and in hospital COVID-19 mortality were included. Data was pooled using a random-effect model. P-values ˂ 0.05 was assumed as statistically significant. We identified 13 observational studies. Pooling 9 studies which categorized vitamin D level, a significant positive relationship was found between vitamin D deficiency and risk of COVID-19 in-hospital mortality (Odds Ratio (OR): 2.11; 95% Confidence Interval (CI): 1.03, 4.32). All subgroup analyses also showed significant relationship between vitamin D deficiency and risk of COVID-19 in-hospital mortality. In the other analysis, pooling data from 5 studies in which vitamin D level was entered as a continues variable, we found an inverse significant association between each unit increment in serum vitamin D concentrations and risk of COVID-19 in-hospital mortality (OR: 0.94; 95% CI: 0.89, 0.99). We found a significant direct association between vitamin D deficiency and elevated risk of COVID-19 in-hospital mortality. Moreover, each unit increment in serum vitamin D levels was associated to significant reduction in risk of COVID-19 mortality. Further prospective studies are needed to confirm our findings. [ABSTRACT FROM AUTHOR]

Background: Quercetin is a flavonoid having anti-cancer properties; however, it has low stability, insufficient bioavailability, and poor solubility. This study aimed to load quercetin on nanoliposomes to enhance its efficiency against SW48 colorectal cancer cells. The cytotoxicity of free-quercetin and quercetin-loaded nanoliposomes on the expression of the epidermal growth factor receptor (EGER) gene was investigated. Methods: This present in vitro study was conducted at Yasuj University of Medical Sciences (Yasuj, Iran) in 2021. In this in vitro study, the lipid thin-film hydration method was used to synthesize quercetin-loaded liposomes. Additionally, high-performance liquid chromatography (HPLC) analyses, dynamic light scattering (DLS), and transmission electron microscopy (TEM) investigations were used to characterize nanomaterials. Following that, MTT, flow cytometry, and real-time PCR were used to investigate the cytotoxicity of quercetin-loaded liposomes on the colorectal cancer cells SW48 cell line, the incidence of apoptosis, and the expression of the EGFR gene in these cells. Statistical analysis was performed using the SPSS (version 26.0), and the graphs were created with the GraphPad Prism version 8.4.3. P<0.05 was considered statistically significant. Results: The nanoparticles were spherical, homogenous, and 150±10 nm in size. According to HPLC, Quercetin had a 98% loading capacity. Although both free quercetin and quercetin-loaded liposomes indicated significant cytotoxicity against cancer cells (P<0.001), the combined form was significantly more active (P=0.008). 50 µg/mL of this compound reduced the viability of SW48 cells by more than 80% (IC50: 10.65 µg/mL), while the viability of cells treated with free quercetin was only 66% (IC50: 18.74 µg/mL). The apoptosis was nearly doubled in the cells treated with quercetin-loaded nanoliposomes compared to free quercetin (54.8% versus 27.6%). EGFR gene expression, on the other hand, was significantly lower in cells treated with quercetin-loaded liposomes than the quercetin alone (P=0.006). Conclusion: When combined with nanoliposomes, quercetin had greater anti-proliferative, apoptotic, and anti-EGFR expression than free quercetin. [ABSTRACT FROM AUTHOR]

The present work is devoted to probing the molecular interaction of N,N',N'-triethylenethiophosphoramide (thioTEPA) with human serum albumin (HSA) using UV-visible and fluorescence spectroscopies. Further, molecular dynamics and molecular docking simulations were used to investigate the binding site of thioTEPA. The outcomes of the spectroscopic observations and also the Stern-Volmer and van't Hoff equations were employed to determine the binding thermodynamic parameters. It was found out that the interaction of thioTEPA with HSA is enthalpy driven through a quenching mechanism that is both static and dynamic at domain I of HSA. No significant changes in the local and overall secondary structure, polarity, and hydrophobicity of HSA were observed. The low values of binding free energies and binding constants are evidence for necessary high dosage of thioTEPA in chemotherapies. These results may be attributed to the spherical geometry and steric hindrance of the free vibrating aziridinyl groups of thioTEPA. Key words: human serum albumin, thioTEPA, fluorescence spectroscopy, molecular dynamics simulation, docking. Resume: Les presents travaux ont pour objectif d'examiner l'interaction moleculaire entre le N,N',N'- triethylenethiophosphoramide (thioTEPA) avec l'albumine serique humaine (HSA) a l'aide de la spectroscopie UV-visible et de la spectroscopie par fluorescence. Nous avons egalement explore le site de liaison du thioTEPA par le biais de la simulation de la dynamique moleculaire et de la simulation interactive de reactions chimiques. Les resultats tires des observations spectroscopiques et des equations de SternVolmer et de van't Hoff ont servi a determiner les parametres thermodynamiques de liaison. Nous avons decouvert que l'interaction entre le thioTEPA et la HSA est gouvernee par l'enthalpie et procede selon un mecanisme d'extinction, tant statique que dynamique, au domaine I du HSA. Nous n'avons observe aucun changement notable de la structure secondaire locale et globale, ni de la polarite ou de l'hydrophobicite de la HSA. Les faibles valeurs des energies libres d'association et des constantes d'association montrent la necessite d'utiliser des doses elevees de thioTEPA en chimiotherapie. Ces resultats pourraient etre attribuables a la geometrie spherique et a l'encombrement sterique des groupements aziridinyles du thioTEPA en oscillation libre. [Traduit par la Redaction] Mots-cles : albumine serique humaine, thioTEPA, spectroscopie par fluorescence, simulation de la dynamique moleculaire, simulation interactive de reactions chimiques., Introduction Plasma proteins play an important role in transportation and deposition of substances such as fatty acids, hormones, and medicinal drugs in the circulatory system. Therefore, it is important to [...]