Chemical Physics Impact最新文献

As a part of the host-defense system of many organisms, defensins are considered a suitable option for treating infection agents. Using the molecular dynamics simulation, this work studied the effects of two important human antimicrobial peptides, human β-defensin 2 and human α-defensin 5 on the SARS-CoV-2 membrane. The results demonstrate that defensin peptides notably alter the bilayer membrane's structure and physicochemical activity leading to a hydrophobic mismatch that impacts transmembrane protein channel function. This study elucidates the antiviral mechanisms of defensins and their therapeutic potential, offering valuable insights for researchers in virology and public health seeking novel medications.

Porous-activated carbons (PAC) show a lot of applications in various fields due to their large surface area and appropriate pore volume, along with decent thermal, chemical, and mechanical stability. Because of these characteristics, PACs are the best choice as an electrode material in supercapacitors (SCs). Due to the utility of PACs, this work reports the transformation of polyvinyl chloride (PVC) into PAC with a surface area of 162.40 m²/g. The synthesized PAC exhibits a maximum specific capacitance (CSP) of 40 F/g at five mV/s in 1-ethyl-3- methylimidazolium thiocyanate ionic liquid (EMIM SCN-IL) electrolyte. Also, no degradation was recorded in the initial C_sp of the fabricated SC, even after 9000 cycles at room temperature. Additionally, using the same PAC in counter electrode dye-sensitized solar cell (DSSC) was also fabricated, and the cell was tested at 1 sun condition, which shows a fill factor of 59.37 % and an efficiency of 1.42 %.

Many human disorders include NF-kB signaling pathways, making IKK a therapeutic target in cancer treatment. Inflammatory illnesses and cancer are examples. COVID-19 is one of several triggers that stimulate NF-kB signaling. The activation of the NF-kB pathway is necessary for COVID-19 to cease its development. To learn more about the mechanism and structural features essential to IKK inhibition (IC₅₀), molecular modeling studies have been undertaken on experimentally reported 503. QSAR analysis explores certain reported and hidden structural features critical for IKKβ inhibition. The OECD guidelines guided the construction of the QSAR model, which achieved all the endorsed threshold values for all validation parameters (R²tr:0.81, R²LMO:0.80, and R²ext:0.78). The present QSAR study shows that IKK inhibitory activity is linked to the following structural features: lipophilic hydrogen atoms within 2 A units of the molecule's center of mass; ring nitrogen atoms within one bond of planar nitrogen atoms; ring carbon atoms exactly four bonds from the non-ring nitrogen atoms; planar nitrogen atoms exactly four bonds from sp2 hybridized carbon atoms; and so on. Pharmacophore modeling highlighted QSAR-identified structural characteristics. To investigate binding, we docked all 503 molecules. The observation indicates that the QSAR and molecular docking/pharmacophore modeling findings are in agreement. Following this, we conducted 200 ns of molecular dynamics simulation to validate the molecular docking protocol. MMGBSA analysis determined the binding energy of the dock complex. Thus, the current study found unique pharmacophoric properties that may assist in optimizing lead/hit compounds for anti-IKKβ activity.

Nucleoside derivatives are essential to medicinal chemistry because they provide biologically active drugs. A 5´-O-palmitoyl derivative (2) was obtained by directly treating cytidine (1) with palmitoyl chloride. New antimicrobial compounds were developed by transforming the 5´-O-acyl derivative into 2´,3´-di-O-acyl derivatives (3-7) with several functionalities. Physicochemical, spectroscopic, and elemental investigations were used to determine the structures of the synthesized compounds. XRD confirmed the crystalline structure of the synthesized compounds. Compounds 3 and 5 exhibited good antibacterial and antifungal activity against bacteria and fungi in vitro. MIC and MBC investigations were performed on compounds 3 and 5 on the basis of their effectiveness. Most of the compounds resulted in >77% fungal mycelial growth. Compound 6 had antiproliferative effects on EAC cells in vitro, with an IC₅₀ value of 1001.11 µg/ml. A DFT study was used to calculate the FMO and MEP parameters, whereas molecular docking identified microbial pathogen prescription drug possibilities. In silico docking studies of cytidine derivatives against the 4URO and 6COX receptors revealed that compounds 3 and 6 had the best docking. In a stimulating environment, a 100-ns MD simulation revealed stable conformation and binding patterns. MD simulation and MM-PBSA analysis of the 3-4URO and 6-6COX complexes indicated good receptor-best-docked molecule interactions. Finally, in vitro and in silico, SAR studies, the acyl chains, (CH₃(CH₂)₁₀CO-) and (C₆H₅CH=CHCO-) incorporated into sugar moieties were shown to have the most promising antimicrobial/anticancer drug-targeting potential.

This study involves a computational analysis of new D-π-A dyes obtained from triphenylamine (TPA), which contain various azo-dye components. The structural, molecular, electrical, and optical properties of these dyes were computed using Density Functional Theory (DFT) and Time-Dependent DFT, utilizing the B3LYP/6–31 G model. Our research specifically aimed to investigate the effects of incorporating different azo dye constituents in the para position of two phenyl groups of TPA. The results indicate that these alterations lead to notably broadened and red-shifted absorption spectra, as well as improved optoelectronic properties that are subject to additional tuning through the manipulation of the π-spacer. The excitation energies and HOMO-LUMO energy levels that have been estimated indicate the presence of effective electron injection and dye regeneration mechanisms. The results concerning the nonlinear optical (NLO) properties suggest that these dyes are likely to demonstrate superior performance in NLO applications. The factors encompassed in this study consist of light-harvesting efficiency (LHE), open-circuit photovoltage ($V_{\text{OC}}$), electron injection driving force ($\Delta G^{\text{inj}}$), dye regeneration driving force ($\Delta G_{\text{reg}}$), excited state lifetime (τ) and reorganization energy (${\lambda }_{\text{total}}$), which has a strong correlation with the electrical current density in a short-circuit ($J_{\text{SC}}$) and DSSC's overall effectiveness. This scientific attempt contributes to the systematic advancement of efficient dyes, demonstrating the possibility for enhanced efficiency in DSSCs. Further validation of computational forecasts and advancement of renewable energy technology necessitate future experimental synthesis and testing.

Polypyrrole (PPy) was synthesized effectively by chemical oxidative polymerization of pyrrole. Organic-inorganic hybrid materials PPy-TiO₂ with different PPy weight percents were prepared by mechanical mixing, by using titanium oxide nanoparticles. The characterizations of PPy-TiO₂ hybrid nanocomposites were analyzed by FTIR, UV–Vis, XRD, TGA & DSC and SEM & EDAX. Fourier transform infrared (FTIR) spectra and X-ray diffraction (XRD) were used to distinguish the structure of the attained PPy-TiO₂ hybrid nanocomposites. UV–vis techniques are proved the polymerization of pyrrole monomer and the strong interaction between PPy and TiO₂ nanoparticles. Thermogravimetric analyzer (TGA-DSC) curves revealed that TiO₂ can decrease the weight loss of nanocomposite and increase the thermal stability of synthesized nanocomposites. The residual mass of the pure Pyy-36.51 %, PPy-TiO₂ (25 %)-64.82 %, PPy-TiO₂ (50 %)-60.82 %, PPy-TiO₂ (75 %)-70.50 % and pure TiO₂- 96.69 % nanocomposites at the residual temperature 497.80 °C. The morphology and molecular structure of the hybrid nanocomposite were characterized by scanning electron microscope & Energy dispersive X-ray analysis spectroscopy (SEM & EDAX). These characterization results confirmed the polymerization of pyrrole and the strong interaction between PPy and TiO₂. The material with outstanding absorption capability that meet in optical application is the challenging way, thus the photocatalytic analysis of PPy-TiO₂ hybrid nanocomposites is merely a admissible results. It is notably the favorable degradation efficiency of pure PPy, the PPy+TiO₂ (25 % 50 % & 75 %) nanocomposites are 82 %, 66 %, 67 % and 53 % respectively.

In this communication, for the first of its kind, CuAl2O4 doped with Ce³⁺ (1-9 mol %) are syn- thesized by solution combustion method using Aloe Vera gel as a reducing agent. The as-formed sample was calcined at 500° C for 3 hours, followed by characterization. The addition of dopants to the copper aluminate matrix didn't alter the crystal structure of the host matrix. Bragg reflec- tions confirm the formation of the cubic phase and also absence of other impurities. The surface morphology consists of nanorods arranged one above the other. The estimated crystallite size was found to decrease from 12 to 9 nm whereas, the direct energy band gap increases from 2.84 to 3.02 eV with an increase in dopant concentration. Under λex = 305 nm excitation, photoluminescence (PL) emission spectra have a high intense peak at 553 nm along with a less intense peak at 472 nm. The peak at 553 nm can be attributed to the existence of oxygen vacancies which arise due to the transition of an electron from the ²D_3/2 → ²F_7/2 of Ce³⁺, however, the peak observed at 472 nm results from the transition of ionized oxygen vacancies (VO) to the valence band caused by the ²D_3/2 → ²F_5/2 transition. The CIE coordinates lie well within the green region with 5758 K aver- age CCT. Further, Cyclic voltammetry analysis was conducted to investigate oxidation and redox peaks, while electrochemical impedance spectroscopy provided insights into ion transport kinetics. Specific capacitance values ranging from 29 to 59 F/g were obtained for CuAl₂O₄:Ce(1-9 mol %) NPs. These findings suggest potential applications for the synthesized material in areas such as display technology as a green nano phosphor and energy storage materials.

Calcium ferrite nanoparticles doped with Chromium (10-50 mol %) are synthesized using the solution combustion method, employing citrus Lemon extract as a reducing agent, followed by a calcination process at 500${}^o$C. Various characterization techniques are employed on the calcined samples. The Bragg reflections resulting from Chromium doping confirm the formation of a singular orthorhombic calcium ferrite phase. Crystallite sizes determined using both Scherrer’s and W-H plot methods found to be decreases with increase in dopant concentration. The surface morphology showcases agglomerated nanoparticles with irregular shapes and sizes, accompanied by pores and voids. The energy band gap found to be increases with increase in dopant concentration from 2.82 to 2.93 eV. The hysteresis loop analysis provides magnetic parameters including saturation magnetization (M${}_s$), remanence (M${}_r$), and coercivity (H${}_c$). As the dopant concentration increases, M${}_s$ and H${}_c$ found to be maximum at 30 mol% cr${}^{3+}$ concentration in CaFe${}_2$O${}_4$ NPs. Linear increase in frequency-dependent conductivity at lower frequencies was observed. The presence of semicircles at low frequencies signifies compliance with the Cole-Cole formula for impedance behavior. Additionally, a detailed discussion on dielectric properties is presented. Notably, the dielectric constant decreases from 4.2 to 2.74 with an increase in dopant concentration. These distinctive attributes position the samples as suitable candidates for memory devices as well as high-frequency device applications.

Dye-sensitized solar cells (DSSCs) offer a promising, cost-effective alternative to conventional photovoltaic systems. Organic sensitizers, capable of capturing a broad spectrum of sunlight, are key components in DSSCs, but their development and testing are often time-consuming and expensive. Quantum chemical calculations, specifically Density Functional Theory (DFT), have emerged as valuable tools to evaluate potential dye candidates, streamlining the design process and reducing costs. This study investigated the molecular structures and photophysical properties of three common dye classes used in high-performance DSSCs: natural pigments, anthocyanidin pigments, and squaraine dyes. Employing DFT and time-dependent DFT (TD-DFT) at the B3LYP/6–31G level, key parameters such as the HOMO-LUMO energy gap, free energy differences for electron injection and dye regeneration, short-circuit current density, total reorganization energy, and open-circuit voltage were analyzed. Additionally, maximum absorption wavelengths and oscillator strength values were calculated. Our findings provide valuable insights into the optical and electrical properties of these natural dyes, aiding DSSC manufacturers in selecting optimal sensitizers. This research highlights the potential of computational methods in accelerating dye development and improving the overall efficiency of DSSC technology.

Using Co-precipitation method, an attempt was made to prepare lithium ferrite. However, during the synthesis, formation of an additional α-Fe₂O₃ phase along with Li_0.5Fe_2.5O₄ was observed. To reduce the α-Fe₂O₃ phase, samples were annealed at 700°C, 800°C and 900°C temperatures for 2 hours. The investigated samples were then characterized using X-Ray diffraction for phase formation and Rietveld analysis was carried out to determine the different structural parameters such as phase percentage, lattice parameter and cell volume. The Chi square values were observed to be within the limit along with goodness of fit less than 3 for all the samples annealed at different temperatures. Surface morphology was carried out using scanning electron microscope and the average grain size was found to be 1.43 µm for the sample annealed at 900°C. Magnetic properties of samples were investigated, and it was observed that all the samples exhibit low values of saturation magnetization along with coercivity. The presence of two phases such as α-Fe₂O₃ phase and lithium ferrite phase dilutes the exchange interaction, tuning the magnetic parameters.