Critical Experimental Parameters Research Articles

Fast fabrication of High-Yield WS2 nanoscrolls via ultrasound sonication

Transforming the bulk of tungsten disulfide (WS2) into one-dimensional (1D) nanoscrolls has potential applications in a variety of fields. The current methods for fabricating (1D) WS2nanoscrolls suffer from low yields, high temperatures, a complicated fabrication process, and the use of surfactants. We have reported a facile and cost-effective approach for fabricating WS2 nanoscrolls in high yield using ultrasound probe sonication (20 KHz) from bulk WS2 in dimethylformamide (DMF) in two hours. Importantly, this simple method achieves a 90 % WS2 nanoscroll yield.This depends on critical experimental parameters such as the choice of solvent, the initial concentration of WS2, and the sonication time. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) measurements confirm that the nanoscrolls have a closely uniform shape, with an interlayer spacing of ∼ 0.62 nm between adjacent layers of WS2 nanoscrolls. Atomic force microscopy (AFM) reveals that the nanoscrolls have a length of approximately 650 nm and a height profile of 5–10 nm, indicating their formation from multiple layers of WS2. We further investigate the fabricated nanoscrolls using other techniques such as X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), and Raman spectroscopy.

Standard Operating Procedure to Optimize Resazurin-Based Viability Assays

The resazurin assay, also known as the Alamar Blue assay, stands as a cornerstone technique in cell biology, microbiology, and drug development. It assesses the viability of cells through the conversion of resazurin into highly fluorescent resorufin. The resulting fluorescence intensity provides a reliable estimate of viable cell numbers. Cytotoxicity assays, such as the resazurin-based method, play a crucial role in the screening of potential drug candidates and in the assessment of pharmaceutical and chemical toxicity. In recent years, inconsistencies have arisen in pharmacogenomic studies, often due to poorly optimized laboratory protocols. These inconsistencies hinder progress in understanding how substances affect cell health, leading to unreliable findings. Thus, the need for standardized and rigorously optimized protocols is evident to ensure consistent and accurate results in cytotoxicity studies. This manuscript describes a standardized procedure for optimizing resazurin-based viability assays to improve the reliability of cytotoxicity data. This optimization approach focuses on critical experimental parameters and data quality, aiming to achieve a level of measurement imprecision of less than 20%. In conclusion, to address the critical issues of reproducibility and reliability, protocol standardization, such as the one described in this manuscript, can greatly enhance the credibility of cytotoxicity studies, ultimately advancing drug safety assessments.

Critical pulse in multi-shot femtosecond laser ablation on metallic surfaces

Thermal effect remains a thorny issue for femtosecond-laser surface engineering and nanostructuring on metallic targets with high pulse energies or high repetition rates, which needs to be paid adequate attentions. Herein, we have experimentally investigated the heat diffusion and accumulations during single-shot and multi-shot femtosecond laser ablation on metallic surfaces. We have for the first time observed a novel phenomenon that the thermal effect was intensified abruptly when the laser-pulse number goes over a threshold (approximately between 10 and 20 for aluminum alloy with laser fluence of 6 J cm−2), accompanied with a dramatic reduction of ablated depth and complicated plasma dynamics. Based on both optical and thermodynamic analysis, we introduced a defocusing-dominated plasma-assistant model for this abnormal thermal effect. This work explored the critical experimental parameters for femtosecond-laser surface modification and processing in micro-scale engineering applications.

Self‐assembly of thiourea intercalated graphene oxide based dual IIP for the SPE coupled FAAS method development of Cu(II) and Pb(II) determination

AbstractA new dual‐template surface imprinted polymer for Cu(II) and Pb(II) was synthesized in one pot. Magnetic graphene oxide was self‐assembled with low cost and environmentally benign thiourea. Presence of sulfur and nitrogen donor atoms provide hooks for coordination and partial reduction of graphene oxide matrix. It was used as an solid‐phase extraction adsorbent for extraction, preconcentration, and coupled with flame atomic absorption spectrometry to manifest performance comparable with inductively coupled plasma atomic emission spectrometry (ICPAES) both in terms of quantification limit as well as interference. The critical experimental parameters such as pH; 4.6, contact time of 15 min and initial concentration of 777 (Qe; 227 mg g−1) and 800 μg L−1 (Qe; 273 mg g−1) for Cu(II) and Pb(II), respectively, were optimized using RSM‐CCD and artificial neural network. The adsorption process was kinetically faster (50% adsorption in 5 min), following fractal‐like‐pseudo‐second‐order (FLPSO) kinetics and Brouers–Sotolongo isotherm model owing to the heterogenous energy landscape. The imprinting factors were in the range of 4–7 in the presence of all coexisting ions. The proposed method was robust in the determination and removal of Cu(II) and Pb(II) from food, ground water, and industry effluents with low limit of detection (Cu(II); 1.03 μg L−1 & Pb(II); 1.79 μgL−1). Spiking and recovery tests were used to assess the method's accuracy. Cu(II)/Pb(II) loaded dual template IIP (DIIP) was utilized to remove anionic dyes with >95% efficiency. Thorough examination of the method and material selectivity (in binary, ternary, and multielement system), multi fold applications of determination, removal of Cu(II), Pb(II), and removal of anionic dyes makes DIIP a promising candidate for environmental remediation.

A new combined technology: Macroporous adsorption resin and high speed counter current chromatography for hydroxytyrosol separation from olive leaf enzymatic hydrolysate

Due to three free hydroxyl groups, hydroxytyrosol (HT) presents strong bioactivity and has broad food and drug application prospects. However, there is no good separation and purification technology. In this study, separation and purification technology of HT from the ethyl acetate extraction of enzymatic hydrolysate from olive leaf (EEEH) was investigated with macroporous adsorption resin (MAR) and high-speed counter-current chromatography (HSCCC) and the separation factors were optimized. First, the adsorption properties of eight MARs (AB-8, S-8, D-101, X-5, XAD-1, XAD-5, NKA-Ⅱ, H-103) for HT enrichment were studied. The results showed that H-103 macroporous resin was adsorbent, sample concentration was 1.5 mg/mL, eluent was 30 % ethanol solution, sample loading rate was 3.0 BV/h, elution velocity was 2.0 BV/h, and HT purity of EEEH was increased from 10.23 % to 40.78 %. Then, solvent systems were examined according to partition coefficients of target component and petroleum ether: ethyl acetate: methanol: water (4:6:4:6, v/v) system was chosen. The critical experimental parameters of HSCCC were optimized as following: revolution speed was 1200 rpm and flow rate was 3 mL/min. The HT purity of macroporous resin purified EEEH was increased from 40.78 % to 85.7 %. Therefore, MAR-HSCCC combined technology could be a very effective approach to separate and purify HT from EEEH.

Differential phase contrast (DPC) mapping electric fields: Optimising experimental conditions.

DPC in Scanning Transmission Electron Microscopy (STEM) is a valuable method for mapping the electric fields in semiconductor materials. However, optimising the experimental conditions can be challenging. In this paper, we test and compare critical experimental parameters, including the convergence angle, camera length, acceleration voltage, sample configuration, and orientation using a four-quadrant segmented detector and a Si specimen containing layers of different As concentrations. The DPC measurements show a roughly linear correlation with the estimated electric fields, until the field gets close to the detection limitation, which is ∼0.5mV/nm with a sample thickness of ∼145nm. These results can help inform which technique to use for different user cases: When the electric field at a planar junction is above ∼0.5mV/nm, DPC with a segmented detector is practical for electric field mapping. With a planar junction, the DPC signal-to-noise ratio can be increased by increasing the specimen thickness. However, for semiconductor devices with electric fields smaller than ∼0.5mV/nm, or for devices containing curved junctions, DPC is unreliable and techniques with higher sensitivity will need to be explored, such as 4D STEM using a pixelated detector.

Cost‐Effective Cholesterol Monitoring by Enzyme‐Based Electrochemical Assay

AbstractHerein we present a practical, disposable, enzyme‐based electrochemical biosensor to revolutionize a rapid and precise measurement of cholesterol level in saliva. To create a biosensor that can measure cholesterol levels, cholesterol oxidase (ChOx) was immobilized on disposable pencil graphite electrode (PGE) via EDC/NHS chemistry. This ChOx‐PGE biosensor has been characterized using cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS). Various critical experimental parameters, including nafion concentration, enzyme concentration, enzyme‐cholesterol interaction time, were optimized ensuring consistency and precision in our results and maintained constant throughout the experiments. Under optimum conditions, the detection limit was found to be 62 μM and the sensitivity of the sensor was calculated as 1112.8 Ohm mM−1 cm−2. The potential interferences such as glucose, ascorbic acid, uric acid, cysteine was selected to test the selectivity and no significant response was observed. Finally, the proposed biosensor was effectively employed to measure cholesterol level in saliva. This biosensor boasts a rapid response time of just 20 minutes and achieves a remarkable detection limit of 95 μM for salivary cholesterol, surpassing existing techniques. Our assay not only offers an innovative solution for cholesterol monitoring but also opens new horizons in point‐of‐care diagnostics with its disposable and practical design.

Salicylic acid as a switchable hydrophilicity solvent for the microextraction of the antibiotic amphotericin B from human urine followed by HPLC-UV analysis

Monitoring the concentration levels of amphotericin B in the human organism is of utmost importance to evaluate the efficacy of the therapy. However, the reported sample preparation protocols for the extraction of this compound are very limited. In this work, salicylic acid is utilized as a switchable hydrophilicity solvent for the microextraction of amphotericin B from human urine samples before the HPLC analysis. The method is based on the phase transition of salicylic acid by changing the pH of the sample enabling efficient dispersion and phase separation in one step. A high contact area of the solidified solvent with the sample solution provided effective extraction of the target analyte. Among others, critical experimental parameters affecting the extraction performance of the drug were systematically investigated. The separation of the drug was carried out on a C8 stationary phase using mixtures of citric acid and methanol as mobile phases. Excellent linearity was observed in the range of 0.1 – 2.0 μg mL−1, while the precision (%RSD) was less than 14.5 % in all cases. The lower limit of quantification was 0.1 μg mL−1, and the limit of detection was 0.03 μg mL−1. The intra-day and inter-day accuracy were satisfactory, being in the range of 85.2 – 109.1 %. The robustness of the microextraction protocol was evaluated using DoE. The green potential and the practicality of the proposed analytical scheme were examined based on Green Analytical Procedure Index (GAPI) and Blue Applicability Grade Index (BAGI), respectively. A BAGI score of 65 was attained, demonstrating good applicability in terms of practicality, while the novel protocol was found to show green merits. The developed method can be used for the analysis of the drug in human urine.

ZrO2 nanoparticles embedded in biochar modified with layered double oxides nanosheets for phosphorus removal by capacitive deionization

Phosphorus in excessive levels can cause eutrophication and destroy the aquatic ecological balance. In this work, a novel capacitive deionization (CDI) anode material was successfully fabricated for phosphorus capture by innovatively embedding ZrO2 in layered double oxides (LDO) - modified biochar (ZrO2@LDO/BC). This approach can overcome the traditional drawbacks of the lack of active sites for phosphorus capture in biochar and the poor electrical conductivity of ZrO2 and LDO. The optimal ZrO2@LDO/BC electrode possessed a high phosphorus uptake capacity (20.36 mg P/g) and low energy consumption (0.0287 kWh/m3 (0.0406 kWh/kg)), owing to its rich mesoporous structure, appropriate conductive framework, excellent electrochemical behavior, and sufficient phosphorus trapping sites. Moreover, a few critical experimental parameters were investigated for their impact on phosphorus removal. The mechanisms revealed were mainly related to the memory effect, electrostatic attractions, and ligand exchange. This work delivered new insights into biomass waste resource utilization and phosphorus control in sewage by constructing modified bagasse-derived carbon anodes.

Pulsed Laser Deposition of Carbon-Based Materials: A Focused Review of Methods and Results

Pulsed Laser Deposition (PLD) is a highly flexible experimental methodology for the growth of thin films of a broad variety of materials, based on the generation of laser-induced plasmas (LIP) with material ablated from a solid target and on the transfer of the ablated material to a substrate. This review is focused on carbon-based materials—specifically, diamond-like carbon (DLC), graphene and carbyne—and will both discuss the influence of the most critical experimental parameters on the obtained materials and present the experimental developments proposed in the recent literature to tailor the properties of the deposited films and optimize the standard PLD technique for production of various carbon-based materials.

Degradation of salicylhydroxamic acid in mineral beneficiation wastewater by dielectric barrier discharge and La-Fe3O4-doped activated carbon: Parametric optimization, kinetics, activation process, and transformation pathway

In this study, the degradation of salicylhydroxamic acid (SHA) in industrial beneficiation wastewater was investigated using dielectric barrier discharge (DBD) and La-Fe3O4-doped activated carbon (La-Fe3O4/AC). The physical and chemical properties of La-Fe3O4/AC were studied using several characterization techniques including scanning electron microscopy, transmission electron microscopy, energy dispersive spectroscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. The response surface methodology was used to optimize three critical experimental parameters of the catalyst: its dosage and the mass ratios of La and Fe3O4. These parameters contributed to the SHA degradation in the following decreasing order: mass ratio of La > catalyst dosage > mass ratio of Fe3O4. The SHA degradation efficiency reached 98.6%, and the synergistic factor was 2.83 at a peak-to-peak discharge voltage of 23 kV. The results showed that the DBD-La-Fe3O4/AC system improved the SHA degradation efficiency and exhibited a significant synergistic effect. Pb2+ and Cu2+ slightly increased the SHA degradation efficiency. Quenching experiments on activated substances confirmed that •OH and O2– were crucial to the degradation of SHA. The O3 and H2O2 generated by the DBD-catalyst system were absorbed by the La-Fe3O4/AC catalyst to produce more •OH. Ten main intermediates were detected in the degradation process of the DBD-catalyst system using HPLC-MS, and three degradation procedures were proposed.

Characterizing and Tailoring Spatial Correlations in Multimode Parametric Down-Conversion

Photons entangled in their position-momentum degrees of freedom serve as an elegant manifestation of the Einstein-Podolsky-Rosen paradox, while also enhancing quantum technologies for communication, imaging, and computation. The multimode nature of photons generated in parametric down-conversion has inspired a generation of experiments on high-dimensional entanglement, ranging from complete quantum state teleportation to exotic multipartite entanglement. However, precise characterization of the underlying position-momentum state is notoriously difficult due to limitations in detector technology, resulting in a slow and inaccurate reconstruction riddled with noise. Furthermore, theoretical models for the generated two-photon state often forgo the importance of the measurement system, resulting in a discrepancy between theory and experiment. Here we formalize a description of the two-photon wave function in the spatial domain, referred to as the collected joint-transverse momentum amplitude (JTMA), which incorporates both the generation and measurement system involved. We go on to propose and demonstrate a practical and efficient method to accurately reconstruct the collected JTMA using a simple phase-step scan known as the $2D\ensuremath{\pi}$ measurement. Finally, we discuss how precise knowledge of the collected JTMA enables us to generate tailored high-dimensional entangled states that maximize discrete-variable entanglement measures such as entanglement of formation or entanglement dimensionality, and optimize critical experimental parameters such as photon heralding efficiency. By accurately and efficiently characterizing photonic position-momentum entanglement, our results unlock its full potential for discrete-variable quantum information science and lay the groundwork for future quantum technologies based on multimode entanglement.

Beam steering with quasi-mosaic bent silicon single crystals: computer simulations for 855 MeV and 6.3 GeV electrons and comparison with experiments

Monte Carlo simulations have been performed for 855 MeV and 6.3 GeV electrons channeling in silicon single crystals at circular bent (111) planes. The aim was to identify critical experimental parameters which affect the volume-deflection and volume-capture characteristics. To these belongs the angular alignment of the crystal with respect to the nominal beam direction. The continuum potential picture has been utilized. The simulation results were compared with experiments. It turns out that the assumption of an anticlastic bending of the crystal, bent on the principle of the quasi-mosaic effect, is not required to reproduce the gross features of the experimental observations for two examined examples.Graphical abstract

Optimization of Biomimetic, Leukocyte-Mimicking Nanovesicles for Drug Delivery Against Colorectal Cancer Using a Design of Experiment Approach.

The development of biomimetic nanoparticles (NPs) has revolutionized the concept of nanomedicine by offering a completely new set of biocompatible materials to formulate innovative drug delivery systems capable of imitating the behavior of cells. Specifically, the use of leukocyte-derived membrane proteins to functionalize nanovesicles (leukosomes) can enable their long circulation and target the inflamed endothelium present in many inflammatory pathologies and tumors, making them a promising and versatile drug delivery system. However, these studies did not elucidate the critical experimental parameters involved in leukosomes formulation. In the present study, we approached the preparation of leukosomes using a design of experiment (DoE) method to better understand the influence of experimental parameters on leukosomes features such as size, size distribution, and protein loading. We also validated this formulation technologically and tested its behavior in in vitro colorectal cancer (CRC) models, including CRC patient-derived tumor organoids (PDOs). We demonstrated leukosomes biocompatibility, endothelium adhesion capability, and tumor target in three-dimensional (3D) settings using CRC cell lines. Overall, our study offers a novel conceptual framework for biomimetic NPs using a DoE strategy and consolidates the high therapeutic potential of leukosomes as a viable drug delivery system for anti-inflammatory and antineoplastic applications.

Recent advances in waste-derived functional materials for wastewater remediation

Water pollution is a major concern for public health and a sustainable future. It is urgent to purify wastewater with effective methods to ensure a clean water supply. Most wastewater remediation techniques rely heavily on functional materials, and cost-effective materials are thus highly favorable. Of great environmental and economic significance, developing waste-derived materials for wastewater remediation has undergone explosive growth recently. Herein, the applications of waste (e.g., biowastes, electronic wastes, and industrial wastes)-derived materials for wastewater purification are comprehensively reviewed. Sophisticated strategies for turning wastes into functional materials are firstly summarized, including pyrolysis and combustion, hydrothermal synthesis, sol–gel method, co-precipitation, and ball milling. Moreover, critical experimental parameters within different design strategies are discussed. Afterward, recent applications of waste-derived functional materials in adsorption, photocatalytic degradation, electrochemical treatment, and advanced oxidation processes (AOPs) are analyzed. We mainly focus on the development of efficient functional materials via regulating the internal and external characteristics of waste-derived materials, and the material’s property-performance correlation is also emphasized. Finally, the key future perspectives in the field of waste-derived materials-driven water remediation are highlighted.

Qualitative High-Throughput Analysis of Subvisible Particles in Biological Formulations Using Backgrounded Membrane Imaging

High-throughput analysis of low-volume samples for detection of subvisible particles (SVPs) in biologic formulations remains an unmet need in the pharmaceutical industry. Some commonly used methods, such as light obscuration and microflow imaging, for SVP analysis are not high throughput and require significant amounts of sample volume, which may impede the collection of SVP data when therapeutic protein amounts are limited, typically during early stages of formulation development. We evaluated backgrounded membrane imaging (BMI) as an orthogonal method for SVP analysis and identified critical experimental parameters. Protein concentration, sample viscosity, and membrane coverage area had to be adjusted for each sample, especially those with high protein concentrations. A comparative analysis of particle counts obtained from BMI, light obscuration, and microflow imaging for five protein samples revealed that particle counts obtained with BMI were significantly higher than those acquired with the other two techniques for all particle size categories. BMI could not accurately count particles in protein-containing samples, as the image analysis software could not accurately trace the boundaries of translucent particles. Based on our results, BMI could be used as an orthogonal method for particle characterization when sample material is limited, such as during the early stages of formulation development or screening.

Theoretical study of the impact of ion acceleration parameters on the mass resolving power in linear MALDI time-of-flight mass spectrometry

This work examines how ion acceleration parameters affect the mass resolving power (Rm) of linear time-of-flight (TOF) mass spectrometry (MS). Ion acceleration parameters have been considered as playing a minor role in determining the Rm in TOF MS. Based on results in two-dimensional topological space calculated in this work, we demonstrate that the length and electrical potential of the ion acceleration region critically affect Rm. The flight-time distribution of ions of m/z 3000 in a 3-m long linear TOF mass spectrometer is analyzed using the coupled space-velocity focusing method. Big data analysis reveals that four types of flight-time distribution are available by adjusting ion acceleration length. The coefficients in the equation of flight-time spread can be used to predict the best length for achieving highest performance. The results show an 18-fold increase in Rm when increasing the length of the ion acceleration region by a factor of ∼35 with respect to conventional design. Adjusting ion extraction parameters cannot provide the same magnitude of improvement. Correlation between Rm and critical experimental parameters are discussed.

Biohydrogen Production From Biomass Sources: Metabolic Pathways and Economic Analysis

The commercialization of hydrogen as a fuel faces severe technological, economic, and environmental challenges. As a method to overcome these challenges, microalgal biohydrogen production has become the subject of growing research interest. Microalgal biohydrogen can be produced through different metabolic routes, the economic considerations of which are largely missing from recent reviews. Thus, this review briefly explains the techniques and economics associated with enhancing microalgae-based biohydrogen production. The cost of producing biohydrogen has been estimated to be between $10 GJ-1 and $20 GJ−1, which is not competitive with gasoline ($0.33 GJ−1). Even though direct biophotolysis has a sunlight conversion efficiency of over 80%, its productivity is sensitive to oxygen and sunlight availability. While the electrochemical processes produce the highest biohydrogen (>90%), fermentation and photobiological processes are more environmentally sustainable. Studies have revealed that the cost of producing biohydrogen is quite high, ranging between $2.13 kg−1 and 7.24 kg−1via direct biophotolysis, $1.42kg−1 through indirect biophotolysis, and between $7.54 kg−1 and 7.61 kg−1via fermentation. Therefore, low-cost hydrogen production technologies need to be developed to ensure long-term sustainability which requires the optimization of critical experimental parameters, microalgal metabolic engineering, and genetic modification.

Role of Hydrodynamics, Li+ Addition and Transformation Kinetics on the Formation of Plate-Like {001} Calcite Crystals

Plate-like calcite crystals with expressed unstable {001} planes are interesting research model for investigations of interfacial interactions of different additive molecules, but also the crystal growth mechanisms. The aim of this study is to reproducibly prepare a significant amount of well-defined plate-like calcite crystals and to investigate the critical experimental parameters. Thus, in precipitation system c(NaHCO3) = c(CaCl2) = 0.1 mol dm−3, the influence of hydrodynamic parameters (mode of mixing of the reaction components) and a presence of lithium ions Li+ within a wide range of concentrations, 0.0 mol dm−3 < c(Li+) < 1.0 mol dm−3, have been studied. In addition, the kinetics of the solution mediated transformation of the initially formed metastable polymorph, vaterite, were followed in order to reproducibly describe the formation of stable calcite with expressed unstable morphology. The results indicate that the plate-like calcite is formed predominantly when the ultrasound irradiation is applied at c(Li+) ≥ 0.3 mol dm−3. On the other hand, when the magnetic and mechanical stirring are applied at higher Li+ concentrations, truncated rhombohedral crystals in a mixture with plate-like crystals are obtained. It was also found that the Li+ addition significantly prolonged the transformation, mainly by inhibiting the crystal growth of calcite.

Assessing the role of CNTs in H2O2/Fe(III) Fenton-like process: Mechanism, DFT calculations and ecotoxicity evaluation

In recent years, multi-walled carbon nanotubes (CNTs), which are emerging nanocatalysts, have received much attention in advanced oxidation processes. CNTs were introduced into H2O2/Fe(III) Fenton-like process to enhance the degradation of bisphenol A (BPA) in this study. The results of the study suggests that CNTs could effectively promote electron transfer from H2O2 to Fe(III) and directly reduce Fe(III) to Fe(II) to accelerate Fe(III)/Fe(II) cycles, in which carbonyl groups and structural defects of CNTs were identified as the major active sites via SEM, Raman, XRD, FTIR and XPS analyses. It was revealed that hydroxyl radical (·OH) majorly contributed to the degradation of BPA, and the generation efficiency of ·OH was significantly increased by 3.2 times with the addition of CNTs. Also, nine intermediate products were identified, and the possible degradation pathways of BPA were proposed through the density functional theory (DFT) calculations and HPLC-MS/MS analysis. The ecotoxicity evaluation of BPA demonstrates that the oxidative degradation of BPA in CNTs/H2O2/Fe(III) system could effectively reduce its environmental risk. The critical experimental parameters including the dosage of Fe(III), H2O2, CNTs, initial pH and various anions (Cl−, HCO3–, SO42−) were investigated, and the reusability experiments indicate that CNTs maintained high stability and reusability during the reaction.