XPS Core Research Articles

Effects of Core and Surface Materials on the Flexural Behavior of Lightweight Composites Sandwich Beams

Sandwich composite elements are used in many sectors thanks to their low weight/strength ratios, high bending strength, good thermal insulation properties, and low costs. It is widely used in the machinery and construction industry, especially in land, sea, and air vehicles. The main objective of this research is to design and produce lightweight, durable, insulated, and low-cost, sustainable building elements that will meet emergency shelter needs after disasters. For housing purposes, 24 sandwich beams were prepared, eight designs with different surface coatings and core materials, and three in each design group. The effects of surface coating and core material on behavior were investigated with four-point bending experiments. Load-displacement relationships were determined from the experiments, and the beams' load-carrying capacities and failure patterns under the effects of bending and shearing were determined. In addition, theoretical methods determined maximum load values and compared them with the results of the experiments. As a result of the experiments, it was concluded that the best-performing design under bending effects was sandwich beams with plywood surface and XPS core.

Could Mushrooms' Secondary Metabolites Ameliorate Alzheimer Disease? A Computational Flexible Docking Investigation.

Herein, we highlight the significance of molecular modeling approaches prior to in vitro and invivo studies; particularly, in diseases with no recognized treatments such as neurological abnormalities. Alzheimer disease is a neurodegenerative disorder that causes irreversible cognitive decline. Toxicity and ADMET studies were conducted using the Qikprop platform in Maestro software and Discovery Studio 2.0, respectively, to select the promising skeletons from more than 45 reviewed compounds isolated from mushrooms in the last decade. Using rigid and flexible molecular docking approaches such as induced fit docking (IFD) in the binding sites of β-secretase (BACE1) and acetylcholine esterase (ACHE), promising structures were screened through high precision molecular docking compared with standard drugs donepezil and (2E)-2-imino-3-methyl-5,5-diphenylimidazolidin-4-one (OKK) using Maestro and Cresset Flare platforms. Molecular interactions, binding distances, and RMSD values were measured to reveal key interactions at the binding sites of the two neurodegenerative enzymes. Analysis of IFD results revealed consistent bindings of dictyoquinazol A and gensetin I in the pocket of 4ey7 while inonophenol A, ganomycin, and fornicin fit quite well in 4dju demonstrating binding poses very close to native ligands at ACHE and BACE1. Respective key amino acid contacts manifested the least steric problems according to their Gibbs free binding energies, Glide XP scores, RMSD values, and molecular orientation respect to the key amino acids. Molecular dynamics simulations further confirmed our findings and prospected these compounds to show significant in vitro results in their future pharmacological studies.

Peculiarities in XPS spectra of Sn/SiO2 layers as an effect of surface charge

X-ray photoelectron spectroscopy based on synchrotron radiation was used to investigate the composition of the observed SnO2-x/Sn:SiO2-x thin layer grown by organometallic chemical vapour deposition on single-crystalline silicon wafer with additional argon ions etching treatment. Due to the formation of a thermodynamic anomaly during in situ layer growth, an efficient oxygen exchange between silicon and tin oxide phases occurs. The present study addresses the effect of localized surface charging and its influence on the obtained XPS core level spectra. We found that due to the high electrical conductivity of metallic tin and the direct coupling of tin particles to the silicon wafer, the XPS Sn 3d5/2 core level spectrum is not affected by the surface charge compared to the highly charged dielectric silicon oxide matrix, as observed for the XPS O 1 s and Si 2p core level spectra. Our results show that the core level spectra of Si 2p and O 1 s are shifted up to 3 eV due to the presence of uncompensated positive charge on the surface of the silica matrix. These results provide insight into the influence of surface charge effects on the analysis of conductor/insulator composite materials and contribute to the application of Sn-based materials in various application concepts related to energy and surface functionalization.

Computational Insights on Migraine and Anxiety in Association with BDNF

Background:: Migraine is an unusual piercing headache on one side of the head. It is due to the dysregulation of epigenetic factors associated with the brain. Migraine affects about one percent of the general population. Despite the recent implementation of worldwide diagnostic criteria for migraine, this disorder remains relatively unknown and is frequently underdiagnosed. Migrainous conditions are also associated with anxiety and stress. This pathologic condition affects the daily life and productivity of the patients. Objective:: Hence, there is a need to develop proper treatment and management strategies to cope with migraine and associated anxiety. Through in silico approaches, this work elucidates to identify the effective lead compounds for migraine and anxiety. Methods:: Brain-derived neurotrophic factor (BDNF) was identified as a possible target for treating migraine and anxiety using computational analysis. Virtual screening and molecular dynamics simulation were used to find potential agonists with high affinities for BDNF. Results:: Based on the results of computational analysis (glide XP score, number of interactions, glide energy, and pharmacokinetic factors), four top hit molecules (Asinex_35922, Enamine_44630, Maybridge_1999, and SMMDB_17457) were identified and taken for further analysis. The hydrogen bond interactions between the agonists and the BDNF protein were verified by dynamics analysis Conclusion:: Computational studies support that BDNF agonist molecules could be effective regulating molecules for migraine and anxiety. For further evidence of the effectiveness of lead compounds in treating migraine and related anxiety, more experimental studies are necessary.

Atomic and electronic structure of monolayer ferroelectric GeS on Cu(111)

Two-dimensional (2D) ferroelectric materials are important materials for both fundamental properties and potential applications. Especially, group Ⅳ monochalcogenide possesses highest thermoelectric performance and intrinsic ferroelectric polarization properties and can sever as a model to explore ferroelectric polarization properties. However, due to the relatively large exfoliation energy, the creation of high-quality and large-size monolayer group Ⅳ monochalcogenide is not so easy, which seriously hinders the integration of these materials into the fast-developing field of 2D materials and their heterostructures. Herein, monolayer GeS is successfully fabricated on Cu(111) substrate by molecular beam epitaxy method, and the lattice structure and the electronic band structure of monolayer GeS are systematically characterized by high-resolution scanning tunneling microscopy, low-energy electron diffraction, <i>in-situ</i> X-ray photoelectron spectroscopy, Raman spectra, and angle-resolved photoelectron spectroscopy, and density functional theory calculations. All atomically resolved STM images reveal that the obtained monolayer GeS has an orthogonal lattice structure, which consists with theoretical prediction. Meanwhile, the distinct moiré pattern formed between monolayer GeS and Cu(111) substrate also confirms the orthogonal lattice structure. In order to examine the chemical composition and valence state of as-prepared monolayer GeS, <i>in-situ</i> XPS is utilized without being exposed to air. The measured spectra of XPS core levels suggest that the valence states of Ge and S elements are identified to be +2 and –2, respectively and the atomic ratio of Ge/S is 1∶1.5, which is extremely close to the stoichiometric ratio of 1∶1 for GeS. To further corroborate the quality and lattice structure of the monolayer GeS film, <i>ex-situ</i> Raman measurements are also performed for monolayer GeS on highly oriented pyrolytic graphene (HOPG) and multilayer graphene substrate. Three well-defined typical characteristic Raman peaks of GeS are observed. Finally, <i>in-situ</i> ARPES measurement are conducted to determine the electronic band structure of monolayer GeS on Cu(111). The results demonstrate that the monolayer GeS has a nearly flat band electronic band structure, consistent with our density functional theory calculation. The realization and investigation of the monolayer GeS extend the scope of 2D ferroelectric materials and make it possible to prepare high quality and large size monolayer group Ⅳ monochalcogenides, which is beneficial to the application of this main group material to the rapidly developing 2D ferroelectric materials and heterojunction research.

Computational Investigation of Endophytic Fungal (Penicillium citrinum CGJ-C2) Compound and Its In-silico Derivatives for the Inhibition of RNA-Dependent RNA Polymerase of SARS-CoV-2

Background: The SARS-CoV2 was responsible for the pandemic situation across the world. SARS-CoV2 is an RNA virus, and its replication depends on RNA Dependent RNA Polymerase (RdRp). Hence, blocking of RdRP would be an alternative strategy to inhibit the virus multiplication without affecting the host physiology. Objective: The current study investigated the inhibitory effect of bioactive compound F3 isolated from P. citrinum CGJ-C2 and its in-silico derivates against RdRp of COVID using computational methods. Methods: Compound F3 and its derivatives were generated computationally, and the crystal structure of RdRp was processed prior to docking. The RdRp and the bioactive compounds were docked using Glide with three levels of precisions. Post-docking MMGBSA analysis and Molecular Dynamic simulations were carried out to study the stability of the docking interactions. Results: Based on the Glide XP score and MMGBSA analysis of fifteen ligands, three leads were selected, compound F3 (-8.655 Kcal/mol), D-1(-8.295 Kcal/mol), and D-14(-8.262 Kcal/mol). These leads (Compound F3, D-1, and D-14) were further evaluated using molecular dynamics (MD) simulation. MD simulations studies showed the stable bonding interaction between LYS500 and ARG569 residues of RdRp with the three lead molecules. Conclusion: Our study highlighted the potential of compounds in terms of binding, interaction stability, and structural integrity. Therefore, these leads can be chosen for further studies in in vitro and in vivo to develop a novel anti-SARS-CoV2 agent with minimal side effects.

Design, synthesis and anti-hyperglycemic assessments of novel 5-benzylidenethiazolidine-2,4-dione derivatives as PPAR-γ agonist

The treatment of diabetes mellitus still relies predominantly on peroxisome proliferator-activated receptor-γ (PPAR-γ) therapy, known for its effectiveness. In this present study, a novel series of benzylidene-linked thiazolidine-2,4-dione compounds was conceptualized, synthesized, and subjected to assessment for their potential antidiabetic properties. Notably, among the compounds examined, 5-((Z)-4-(((E)-Propylidene)amino)benzylidene)thiazolidine-2,4-dione, designated as 4c, emerged as the most promising candidate, exhibiting the highest PPAR-γ agonistic activity with an EC50 value of 0.35 ± 0.52 μM. Additionally, molecular docking investigations were conducted on twelve 2,4-thiazolidinedione compounds, with a pyrazole moiety incorporated, within the ligand binding domain of PPAR-γ. Compound 4c, in particular, demonstrated a Glide XP score of −9.104, surpassing the score of the crystal ligand (Glide XP score = −7.482). Notably, both exhibited similar interactions with key amino acids, including HIE323, SER289, and GLN286. Furthermore, three derivatives (4a-c) with promising PPAR-γ agonistic activity and favorable molecular docking scores underwent in vivo evaluation for their capacity to lower blood glucose levels using a streptozotocin-induced diabetic mice model. In comparison to the reference drug pioglitazone, Compound 4c displayed commendable in-vivo performance across multiple parameters, encompassing serum HDL, serum LDL, serum total cholesterol, and serum triglyceride levels. Molecular dynamics simulations provided insights into the impact of ligand 4c, indicating its role in enhancing protein stability and rigidity. These findings emphasize its potential as a potent protein inhibitor, thus opening novel avenues for the intelligent design of molecules with high efficacy in the management of hyperglycemia.

Discerning of isatin-based monoamine oxidase (MAO) inhibitors for neurodegenerative disorders by exploiting 2D, 3D-QSAR modelling and molecular dynamics simulation

Almost a billion people worldwide suffer from neurological disorders, which pose public health challenges. An important enzyme that is well-known for many neurodegenerative illnesses is monoamine oxidase (MAO). Although several promising drugs for the treatment of MAO inhibition have recently been examined, it is still necessary to identify the precise structural requirements for robust efficacy. Atom-based, field-based, and GA-MLR (genetic algorithm multiple linear regression) models were created for this investigation. All of the models have strong statistical (R 2 and Q 2) foundations because of both internal and external validation. Our dataset’s molecule has a higher docking score than safinamide, a well-known and co-crystallized MAO-B inhibitor, as we also noticed. Using the SwissSimilarity platform, we further inquired which of our docked molecules would be the best for screening. We chose ZINC000016952895 as the screen molecule with the best binding docking score (XP score = −13.3613). Finally, the 100 ns for the ZINC000016952895-MAO-B complex in our MD investigations is stable. For compounds that we hit, also anticipate ADME properties. Our research revealed that the successful compound ZINC000016952895 might pave the way for the future development of MAO inhibitors for the treatment of neurological disease. Communicated by Ramaswamy H. Sarma

Virtual screening, molecular simulations and bioassays: Discovering novel microsomal prostaglandin E Synthase-1 (mPGES-1) inhibitors

Microsomal prostaglandin E synthase-1 (mPGES-1) is an inducible prostaglandin E synthase expressed following exposure to pro-inflammatory stimuli. The mPGES-1 enzyme represents a new target for the therapeutic treatment of acute and chronic inflammatory disorders and cancer. In the present study, compounds from the ZINC15 database with an indole scaffold were docked at the mPGES-1 binding site using Glide (high-throughput virtual screening [HTVS], standard precision [SP] and extra precision [XP]), and the stabilities of the complexes were determined by molecular simulation studies. Following HTVS, the top 10% compounds were retained and further screened by SP. Again, the top 10% of these compounds were retained. Finally, the Glide XP scores of the compounds were determined, 20% were analyzed, and the Prime MM-GBSA total free binding energies of the compounds were calculated. The molecular simulations (100 ns) of the reference ligand, LVJ, and the two best-scoring compounds were performed with the Desmond program to analyze the dynamics of the target protein-ligand complexes. In human lung cells treated with the hit compounds, cell viability by colorimetric method and PGE2 levels by immunoassay method were determined. These in vitro experiments demonstrated that the two indole-containing hit compounds are potential novel inhibitors of mPGES-1 and are, therefore, potential therapeutic agents for cancer/inflammation therapies. Moreover, the compounds are promising lead mPGES-1 inhibitors for novel molecule design.

Mangosteen Metabolites as Promising Alpha-Amylase Inhibitor Candidates: In Silico and In Vitro Evaluations.

Diabetes is a chronic metabolic disorder characterized by raised glucose levels in the blood, resulting in grave damage over time to various body organs, including the nerves, heart, kidneys, eyes, and blood vessels. One of its therapeutic treatment approaches involves the inhibition of enzymes accountable for carbohydrate digestion and absorption. The present work is aimed at evaluating the potential of some reported metabolites from Garcinia mangostana (mangosteen, Guttiferae) as alpha-amylase inhibitors. Forty compounds were assessed for their capacity to inhibit alpha-amylase using in silico studies as well as in vitro assays. Molecular docking was carried out to analyze their binding capacities in the 3D structure of alpha-amylase (PDB ID: 4GQR). Among the tested compounds, 6-O-β-D-glucopyranosyl-2,4,6,3',4',6'-hexahydroxybenzophenone (8), aromadendrin-8-C-glucoside (5), epicatechin (6), rhodanthenone (4), and garcixanthone D (40) had a high XP G.score and a Glide G.score of -12.425, -11.855, -11.135, and -11.048 Kcal/mol, respectively. Compound 8 possessed the XP and Glide docking score of -12.425 Kcal/mol compared to the reference compounds myricetin and acarbose which had an XP and Glide docking score of -12.319 and 11.201 Kcal/mol, respectively. It interacted through hydrogen bond formations between its hydroxyl groups and the residues His 101, Asp 197, Glu 233, Asp 300, and His 305, in addition to water bridges and hydrophobic interactions. Molecular mechanics-generalized born surface area (MM-GBSA) was used to calculate the binding free energy and molecular dynamic studies that indicated the stability of the alpha-amylase-compound 8 complex during the 100 ns simulation in comparison with myricetin- and acarbose-alpha-amylase complexes. Additionally, the in vitro alpha-amylase inhibition assay findings validated the in silico study's findings. This could further validate the potential of G. mangostana as a candidate for diabetes management.

Structural modelling and in silico pharmacology of β-carboline alkaloids as potent 5-HT1A receptor antagonists and reuptake inhibitors

Serotonin (5-HT) antagonists and reuptake inhibitors (SARIs) are atypical antidepressants for managing major depressive disorder. They are oftentimes applied as adjuvants for ameliorating aftereffects of SSRI antidepressants including insomnia and sexual dysfunction. The few available candidates of this class including lorpiprazole and trazodone also display some daunting side effects, making a continuous search for improved alternatives essential. Natural β-carboline alkaloids (NβCs) are interestingly renowned with broad pharmacological spectrum against several neuropsychiatric disorders including depression. However, their potentials as SARIs remain underexplored. In this study, 982 NβCs retrieved from the Ambinter-Greenpharma (Amb) database were virtually screened for potent SARI alternatives using computational and biocheminformatics approaches: homology modelling of 5-HT1A receptor, Glide HTVS, SP and XP molecular docking, molecular dynamics (MD) simulation, ADMET and mutagenicity predictions. The homology receptor was validated as a good representative of human 5HT1A receptor using the RCSB structure validation and quality protocols. From the virtual screening against the 5-HT1A receptor, Amb ligands, Amb18709727 and Amb37857532 showed higher binding affinities by XP scores of −8.725 and −7.976 kcal/mol, and MMGBSA of −87.972 and −107.585 kcal/mol respectively compared to lorpiprazole, a reference SARI with XP score and MMGBSA of −6.512 and −62.788 kcal/mol respectively. They maintained ideal contacts with pharmacologically essential amino acid residues implicated in SARI mechanisms and expressed higher stability and compactness than lorpiprazole throughout the trajectories of 100 ns MD simulation. They also displayed interesting ADME, druggability, low toxicity and mutagenicity profiles, ideal for CNS drug prospects, thus, recommended as putative SARI candidates for further study.

Quantum chemical calculations, spectroscopic studies and molecular docking investigations of the anti-cancer drug quercitrin with B-RAF inhibitor

Quercitrin is an anti-lung cancer agent. It is a naturally occurring flavonoid and its derivatives are mainly present in nuts and beverages. It is mainly available as a glycoside, and the quercitrin glycosides are found to prevent the metastasis of cancer. Quercitrin is optimized with 6–311++G(d,p) basis set using the B3LYP method to attain its minimum energy structure. The vibrational studies of the Quercitrin compound were elucidated with reference to Potential Energy Distribution (PED). The geometrical parameters were obtained and correlated with experimental values. To examine the nature of the charge transfer mechanism of Quercitrin, the HOMO-LUMO energy gap is computed. The anti-cancer activity of Quercitrin has been explored using molecular docking study that are used to estimate how the ligand interacts with protein, specifically to identify the best-fit orientation of the ligand, its binding mode, and intermolecular interactions of amino acid residues in the binding region of B-RAF kinase protein. The binding affinity of the compound Quercitrin (-7.14 kcal/mol) was found using AutoDock and validated with a Glide XP score in Schrodinger tool (-8.01 kcal/mol). MD simulations of protein-ligand complexes were monitored for 100 ns, from which the RMSD, RMSF, Rg, H-bonds, and interaction energy calculations were executed. From these investigations, it is identified that the compound quercitrin has maintained good structural stability, compactness, higher Hydrogen bonds, and interaction energies than the Imidazopyridinyl benzamide inhibitor.

Molecular modelling and structure-activity relationship of a natural derivative of o-hydroxybenzoate as a potent inhibitor of dual NSP3 and NSP12 of SARS-CoV-2: in silico study

The nsp3 macrodomain and nsp12 (RdRp) enzymes are strongly implicated in the virulent regulation of the host immune response and viral replication of SARS-CoV-2, making them plausible therapeutic targets for mitigating infectivity. Remdesivir remains the only FDA-approved small-molecule inhibitor of the nsp12 in clinical conditions while none has been approved yet for the nsp3 macrodomain. In this study, 69,067 natural compounds from the IBScreen database were screened for efficacious potentials with mechanistic multitarget-directed inhibitory pharmacology against the dual targets using in silico approaches. Standard and extra precision (SP and XP) Maestro glide docking analyses were employed to evaluate their inhibitory interactions against the enzymes. Four compounds, STOCK1N-45901, 03804, 83408, 08377 consistently showed high XP scores against the respective targets and interacted strongly with pharmacologically essential amino acid and RNA residues, in better terms than the standard, co-crystallized inhibitors, GS-441524 and remdesivir. Further assessments through the predictions of ADMET and mutagenicity distinguished STOCK1N-45901, a natural derivative of o-hydroxybenzoate as the most promising candidate. The ligand maintained a good conformational and thermodynamic stability in complex with the enzymes throughout the trajectories of 100 ns molecular dynamics, indicated by RMSD, RMSF and radius of gyration plots. Its binding free energy, MM-GBSA was recorded as –54.24 and –31.77 kcal/mol against the respective enzyme, while its structure-activity relationships confer high probabilities as active antiviral, anti-inflammatory, antiinfection, antitussive and peroxidase inhibitor. The IBScreen database natural product, STOCK1N-45901 (2,3,4,5,6-pentahydroxyhexyl o-hydroxybenzoate) is thus recommended as a potent inhibitor of dual nsp3 and nsp12 of SARS-CoV-2 for further study. Communicated by Ramaswamy H. Sarma

In silico study for the identification of potential compounds as PIM-1 kinase inhibitors

PIM kinases are a group of serine/threonine kinases that are classified into three isoforms: PIM1, PIM2, and PIM3. Pim-1 kinase is a critical enzyme that is involved in cell growth, cell survival, differentiation, apoptosis, senescence and drug resistance. The PUBMED database has been taken for the screening of PIM-1 kinase inhibitor. This database, further, screened by Lipinski Rule of five, HTVS, standard precision (SP), and extra precision (XP) methodologies. 2OJF protein of PIM-1 kinase was taken for molecular docking. The compound 1a showed good docking scores, SP = −7.244 and XP = −8.6, whereas 1i showed minimal SP and XP scores. These studies may be used for the further development of potential compounds against PIM-1 kinase.

Modulation doping and charge density wave transition in layered PbSe-VSe2 ferecrystal heterostructures.

Controlling charge carrier concentrations remains a major challenge in the application of quasi-two-dimensional materials. A promising approach is the modulation doping of transport channels via charge transfer from neighboring layers in stacked heterostructures. Ferecrystals, which are metastable layered structures created from artificial elemental precursors, are a perfect model system to investigate modulation doping, as they offer unparalleled freedom in the combination of different constituents and variable layering sequences. In this work, differently stacked combinations of rock-salt structured PbSe and VSe2 were investigated using X-ray photoelectron spectroscopy. The PbSe layers act as electron donors in all heterostructures, with about 0.1 to 0.3 donated electrons per VSe2 unit cell. While they initially retain their inherent semiconducting behavior, they themselves become metallic when combined with a larger number of VSe2 layers, as evidenced by a change of the XPS core level lineshape. Additional analysis of the valence band structure was performed for selected stacking orders at different sample temperatures to investigate a predicted charge density wave (CDW) transition. While there appear to be hints of a gap opening, the data so far is inconclusive and the application of spatially resolved techniques such as scanning tunneling microscopy is encouraged for further studies.

Identification of novel potential anti-diabetic candidates targeting human pancreatic α-amylase and human α-glycosidase: an exhaustive structure-based screening

Diabetes is a major health issue that has reached alarming levels, affecting nearly half a billion people worldwide. It is a serious and long-term medical condition that has a major impact on the lives and well-being of individuals, families, and societies. Diabetes is among the top 10 diseases responsible for death among adults, with an expected increase to 10.2% (578 million) by 2030 and 10.9% (700 million) by 2045. Carbohydrates are absorbed into the body upon hydrolysis by human pancreatic α-amylase and other intestinal enzymes, such as human α-glucosidase. α-Amylase and α-glucosidase are well-validated therapeutic targets in the treatment of type II diabetes mellitus (T2DM) and play a vital role in modulating blood glucose levels after a meal. Herein, we report novel and diverse molecules identified as potential candidates that are predicted to have affinities for α-amylase and α-glucosidase. These molecules were identified via hierarchical multistep docking of small-molecule databases with estimated binding free energies. A Glide XP score cutoff of –8.0 kcal/mol was implemented to filter out non-potential molecules from the database. Four molecules, amb22034702, amb18105639, amb17153304, and amb9760832, were identified after an exhaustive computational study involving the evaluation of binding interactions and assessment of the pharmacokinetics and toxicity profiles. In-depth analysis of protein–ligand interactions was performed using a 100 ns molecular dynamics (MD) simulation to establish dynamic stability. Furthermore, MM-GBSA based binding free energies were computed for 1000 trajectory snapshots to ascertain the strong binding affinities of these molecules for α-amylase and α-glucosidase. The identified molecules can be considered as promising candidates for further drug development through necessary experimental assessments.

Novel Anti-Tubulin Compounds from Trigonella foenum-graecum Seeds; Insights into In-vitro and Molecular Docking Studies.

BackgroundFenugreek, also known as Trigonella foenum-graecum L, is a natural plant that belongs to the Fabaceae family and has been known as a promising source of bioactive compounds. It has been widely used as traditional medicine since it has shown to lower blood glucose, manage cholesterol levels and further aid in the prevention and treatment of cancer. Herein, we aim to evaluate the anticancer activity of methanolic fenugreek seed extract against several cancer cell lines.MethodsWe sought to investigate the phytochemical classes present in multiple fenugreek seeds extracts using HPLC-DAD followed by LC/MS, predict and investigate anticancer activity using PASS online webserver, the CellTiter-Glo assay, evaluate ADME properties, and perform molecular docking for all bioactive compounds via Maestro software.ResultsMultiple extracts exhibited distinct phytochemical classes that demonstrated different biological activities. Fenugreek methanolic extract contains flavonoid chemical class, which showed the highest anticancer activity against the HCT8 cell line of colorectal cancer (IC50 of 8.83 μg/mL), followed by KAIMRC1 breast cancer cell line (IC50 of 35.06 μg/mL), HL60 leukemia cell line (37.80 μg/mL), MDA-MB-231 breast cancer cell line (38.51 μg/mL), and lastly, HCT116 colorectal cancer cell line with IC50 of 56.03 μg/mL. In contrast, the chloroform extract was inactive. The molecular docking study for all the bioactive compounds suggested that flavonoids F6 (−9.713 and −12.132), F7 (−10.166 and −12.411), and F11 (−10.084 and −13.516) possess the highest docking scores through SP and XP scores, respectively.ConclusionThe obtained results confirm that the bioactive compounds present in fenugreek seeds exhibit anticancer activity against several cancer cells that can mediate via tubulin polymerization inhibition. Although our study has evaluated the anticancer potential of Trigonella foenum-graecum as a promising natural source for new anticancer agents, fenugreek biological activity needs further research and investigations on their mechanism of action and toxicity profile.

Shake loss intensities in x-ray photoelectron spectroscopy: Theory, experiment, and atomic composition accuracy for MgO and related compounds

The relative intensities of XPS core levels, scaled by their photoionization cross sections, are regularly used to determine sample atomic composition. Cross sections, however, give the intensity to all possible final states for the core ionizations, not just to the main peak. This includes all intrinsic satellite structure (shake states and, for open shell systems, the different ionic multiplets). In practice, for solids, this is usually experimentally impossible to determine accurately because such a satellite structure sits on the inelastically scattered electron background and cannot be easily separated. Therefore, usually, only the intensity of the main peak is used. This limits the ultimate possible accuracy of XPS composition determination. The purpose of the present paper is to examine the contributions that a theoretical analysis of losses of intensity can make to improve quantitation. For an MgO single crystal, we show that the correct stoichiometry of 1:1 can be recovered using the theoretical analysis of the experimental MgO peak ratio intensities. For materials with a sufficient bandgap for the XPS main peaks to be separated from the scattered background, the intensity of main peaks can often be accurately determined. Thus, if one uses theory to calculate that fraction of the total intensity lost from a main peak into all its satellite structure, the intensity of just main peaks could then be used to more accurately determine relative atom % composition. This work tests this approach using a single crystal MgO (50% Mg, 50% O) standard. Ab initio electronic structure theory of representative MgO clusters is used to determine Hartree–Fock wave functions for the ground state and final ionized states corresponding to the main Mg 2p and O1s XPS peaks of the oxide. The sudden approximation, SA, is used to determine the fractional losses from these main peaks to shake satellites, which is found to be greater for O1s than Mg2p. This results in predicted “apparent composition” for stoichiometric MgO of 55.2% Mg, 44.8% O instead of the true 50% Mg, 50% O. Equivalent theory for CaO results in a predicted apparent Ca value of 53.4%. Experimentally, using Mg2s or 2p intensity ratio to O1s, we find values between 52.2% and 56.0% Mg using two crystals and four different instrument electron pass energies. The average value of the measurements is 54.5% Mg when corrected for the presence of an adventitious carbon overlayer and slight surface hydroxide. Though this agreement with theory may be somewhat fortuitous, given the potential experimental errors, which are fully discussed, it is similar to that in our earlier study on LiF. We also present preliminary experimental data on Mg(OH)2 and MgSO4, which show a similar trend of apparently higher than 50% Mg, but we have no theory values. We are not yet able to experimentally test for validation of the difference between apparent composition for MgO (55.2% Mg) and CaO (53.4% Ca), owing to significant carbonate formation at the surface of the single crystal CaO. An important conclusion is that the theoretical determination of shake losses, obtained with ab initio wavefunctions and the SA, is likely to be a useful way to calibrate the accuracy and reliability of compositions obtained from XPS intensities and merits further study.

SPR based gold nano-probe as optical sensor for cysteine detection via plasmonic enhancement in the presence of Cr3+

A selective and sensitive detection of L-cysteine (Cys) is an important tool for various biological studies. Here, Au nanoparticles (NPs) were prepared by chemical reduction technique. The probe was developed to detect and quantify Cys in the presence of Cr3+ ions which acts as a cross linker. The citrate capped Au NPs probe was analyzed by UV–visible spectrophotometry, TEM, EDAX, FTIR, DLS, XPS and zetasize. The zeta potential and effective size of Au NPs were −41.22 mV and 12 nm, respectively. The Cys interaction with Au NPs showed drastic colour variation from red to purple and colourless with rapid response time of 1 min. The limit of detection (LOD) of Au NPs probe was as low as 0.012 nM. The TEM image of Au NPs after Cys interaction verified the aggregation that resulted in colour change. The XPS core level scans of Au 4f showed 0.3 eV red shift when Cyswas interacted. The Au NPs sensor is highly selective for Cys with excellent reproducibility. Acidic pH slightly favored Cys detection. Further, the probe was applied to estimate Cys quantity from milk, urine, blood and environmental augmented samples in the presence of other amino acids . The study suggests that the proposed Au NPs could detect Cys with high accuracy from various biological samples.

Influence of Oxygen Ion Migration from Substrates on Photochemical Degradation of CH3NH3PbI3 Hybrid Perovskite

Measurements of XPS survey, core levels (N 1s, O 1s, Pb 4f, I 3d), and valence band (VB) spectra of CH3NH3PbI3 (MAPbI3) hybrid perovskite prepared on different substrates (glass, indium tin oxide (ITO), and TiO2) aged under different light-soaking conditions at room temperature are presented. The results reveal that the photochemical stability of MAPbI3 depends on the type of substrate and gradually decreases when glass is replaced by ITO and TiO2. Also, the degradation upon exposure to visible light is accompanied by the formation of MAI, PbI2, and Pb0 products as shown by XPS core levels spectra. According to XPS O 1s and VB spectra measurements, this degradation process is superimposed on the partial oxidation of lead atoms in ITO/MAPbI3 and TiO2/MAPbI3, for which Pb–O bonds are formed due to the diffusion of the oxygen ions from the substrates. This unexpected interaction leads to additional photochemical degradation.