Chromatography Research Articles

Optimization and modeling of biodiesel production from oleic acid in plug flow reactor

In recent years, biodiesel has been preferable to fossil fuels because of its renewability, biodegradability, and producibility from various wastes. In this study, the esterification reaction between oleic acid and methanol was carried out in the presence of sulfuric acid, which is a homogeneous acid catalyst, to produce biodiesel. Experiments were carried out in a plug flow reactor (PFR) and a batch reactor. The experimental conditions with the highest conversion obtained in the PFR were determined and applied to the batch reactor and results were compared. The effects of temperature (45, 55, 65 in Celsius), catalyst concentration (2%, 4%, 6% by weight), and methanol/oleic acid mole ratio (3, 6, 9) on oleic acid conversion were examined in the PFR. Retention times at different flow rates were calculated to determine the reaction time in the PFR and reactions were carried out between 2 and 6 minutes. In the reactions carried out in the PFR, the highest conversion value was obtained as 97.33% under conditions where the catalyst concentration was 6% by weight, the temperature value was 55oC and the alcohol/acid mole ratio was 6:1. These conditions were applied to the batch reactor and the conversion value was found to be 50%. When the experimental results were examined, it was seen that the effect of temperature and alcohol/acid ratio on the conversion was greater than the effect of the catalyst concentration on the conversion. The modeling of oleic acid/methanol esterification, i.e., biodiesel production, at specific boundary values was found to follow a cubic dependence in the general dependence equation via Response Surface Methodology.

UNLOCKING THE POTENTIAL OF BIOENERGY: A SUSTAINABLE SOLUTION FOR ENERGY SECURITY, WASTE MANAGEMENT, AND ENVIRONMENTAL CONSERVATION

The study was carried out to generate biogas from fresh cowdung. Proximate analysis on the cow-dung sample revealed moisture content to be 60.53%, Ash content 11.01%, total solids 39.47%, volatile matter 10.78%, protein content 12%, nitrogen content 1.6%, carbohydrate 5.68% and fixed carbon 17.68%. The pH and Temperature were measured daily at 2:00pm, the temperature ranged from 30OC-38OC and the pH range was 6.7 - 7.2. The gas produced was measured daily by calculating the volume with the height increased daily up to 36 days. The results showed a typical biogas production curve, consisting of lag, acceleration, maturation, and decline phases. The optimal retention time for biogas production is identified as 20-30 days, during which biogas yields are highest. The findings indicate that microorganisms require an initial adaptation period (Days 1-3) before biogas production commences, followed by a significant increase in production (Days 11-20) and a stable production rate (Days 21-30). A decline in production is observed after 30 days. This study highlights the importance of retention time in biogas production and demonstrates the need for monitoring production kinetics to optimize retention time for specific substrates and microbial communities. The results have implications for the design and operation of biogas production systems.

Anti-dengue viral activity of Glycyrrhiza glabra roots in Vero cells

Despite being a global public health problem, there are no antiviral agents for dengue. Plants are the sources of most approved drugs and many phytochemicals have exhibited in vitro antiviral activity. We explored the antiviral potential of the aqueous extract of Glycyrrhiza glabra roots (GGaq) on dengue viruses. Plaque reduction antiviral assay for half maximal inhibitory concentrations (IC50) was done in Vero cells infected with dengue serotypes 1–4 and exposed to varying concentrations of GGaq. Half-maximal cytotoxic concentration (CC50) of the GGaq was 651.9 µg/mL. The IC50 of the four dengue serotypes (10–50 µg/mL) indicated moderate inhibition by GGaq. 98–100% inhibition of all dengue serotypes was seen with GGaq at the maximum nontoxic dose. Preparative thin layer chromatography of GGaq, isolated sub fractions E and F which had low to moderate antiviral activity (IC50 12.65–85.95 and IC50 13.14–69.27 respectively). They exhibited good therapeutic potential only for dengue serotype-4. Virus adsorption to cells was significantly inhibited by GG (50%) and sub fraction E (24.9%). Chloroquine diphosphate was used as the positive control in all assays. The aqueous extract of GG was non-toxic and had better antiviral activity than sub fractions E and F.

Evaluation of Biochemical Methane Potential and Kinetics of Organic Waste Streams for Enhanced Biogas Production

Organic waste has the potential to produce methane gas as a substitute for petrol-based fuels, while reducing landfilling and possible environmental pollution. Generally, anaerobic digestion (AD) is used only in wastewater treatment plants as a tertiary stage of sewage sludge treatment, generating a fraction of the energy that such process plants require. In this study, four different wastes—food waste (FW), dairy industry waste (DIW), brewery waste (BW), and cardboard waste (CBW)—were tested for biogas production. The biochemical methane potential (BMP) of each sample was evaluated using an automatic methane potential system (AMPTS). Operating parameters such as pH, temperature, total solids, and volatile solids were measured. Experiments on the anaerobic digestion of the samples were monitored under mesophilic conditions (temperature 37 °C, retention time 30 days). Specific methane yields (SMYs), as well as the theoretical methane potential (BMPth), were used to calculate the biodegradability of the substrates, obtaining the highest biodegradability for BW at 95.1% and producing 462.3 ± 1.25 NmL CH4/g volatile solids (VS), followed by FW at an inoculum-to-substrate ratio (ISR) of 2 at 84% generating 391.3 NmLCH4/g VS. The BMP test of the dairy industry waste at an inoculum-to-substrate ratio of 1 was heavily inhibited by bacteria overloading of the easily degradable organic matter, obtaining a total methane production of 106.3 NmL CH4/g VS and a biodegradability index of 24.8%. The kinetic modeling study demonstrated that the best-fitting model was the modified Gompertz model, presenting the highest coefficient of determination (R2) values, the lowest root means square error (RMSE) values for five of the substrates, and the best specific biogas yield estimation with a percentage difference ranging from 0.3 to 3.6%.

Unveiling the slow digestion and peptide profiles of polymerised whey gel via heat and TGase crosslinking: An in vitro/vivo perspective

Polymerised whey is widely used in dairy products and can affect digestibility when its high-molecular-weight aggregates and gel structure are modified. This study investigated the digestibility, peptide profiles and satiety of modified whey protein isolate (MWPI) pre-heated with transglutaminase. Results showed that 43.06 % of MWPI was digested during the 4-h in vitro digestion, indicating a slow digestion rate. Compared with whey protein isolate (WPI), MWPI yielded 103 peptides with higher abundance following in vitro digestion, including 17 angiotensin-converting enzyme inhibitors and 1 dipeptidyl peptidase-4 inhibitor. Visual analytics indicated differential peptides located at distinct α-helix and β-sheet of β-lactoglobulin, α-lactalbumin and bovine serum albumin. MWPI gavage extended stomach retention time, decreased intestinal propulsion rate from 75.60 % (WPI group) to 33.72 % in 30 min and enhanced satiety within 120 min compared with WPI. Overall, whey polymerisation modulates protein–enzyme interactions, releasing different peptides and enhancing satiety.

Performance Evaluation of Sponge Anaerobic Baffled Reactor for Municipal Wastewater Treatment

The anaerobic baffled reactor (ABR) is a decentralized treatment system that is commonly used for municipal wastewater treatment. Slower growth rate of anaerobic microorganisms requires extended hydraulic retention time (HRT), leading to a larger bioreactor volume. In this study, polyurethane sponge sheets were provided in a six-compartment ABR for retention and growth of biomass to improve its treatment performance at shorter HRTs. Polyurethane sponge was selected for its low cost, durability, availability, easy emplacement, and high voidage. The sponge anaerobic baffled reactor (SABR) was operated within a temperature range of 35 ± 1 °C at HRTs of 18, 12, 8, and 6 h to evaluate its treatment performance. Average removal efficiencies ranged from 60–77% for organics, 74–81% for total suspended solids (TSS), 50–66% for total nitrogen (TN), and 47–57% for total phosphorus (TP). The shortest HRT was 8 h with average removal efficiencies of 74, 63, 64, and 52% for organics, TSS, TN, and TP, respectively, to meet effluent discharge limits. With the shortest HRT of 8 h, the SABR demonstrated low volume requirements, thereby making it an efficient solution for decentralized wastewater treatment, particularly advantageous for developing countries with warm climates.

Growth and Production Kinetics, Extraction, and Characterization of Microbial Biosurfactants

The present study emphasizes the Growth, production and characterization of the biosurfactant produced by Pseudomonas aeruginosa, Micrococcus luteus and Serratia marcescens. These three isolates study for growth Kinetics and production kinetics. HPLC analysis of biosurfactant shows major peak and minor peak with different retention time on the basis of sample spend a different amount of time on the column according to its chemical composition.

Simultaneous monitoring of epoxy value, hydroxyl value, and polymeric hydroxyl value during the ring opening of epoxidized soybean oils based on low‐field nuclear magnetic resonance coupled with chemometrics

AbstractLow‐field nuclear magnetic resonance technique combined with chemometrics was employed to establish the quantitative models for rapidly monitoring the changes of indicators (hydroxyl value (OHV), epoxy value (EV), polymeric hydroxyl value (POHV, reflecting the degree of polyetherification)) during the ring opening of epoxidized soybean oils. Comprehensively considering the variations of peak retention times and peak areas of LF‐NMR spectra, OHVs of vegetable oils‐based polyols were divided into low OHV (LOHV, 1.7–91.9 mg KOH/g) group and high OHV (HOHV, 94.1–229.4 mg KOH/g) group. In both LOHV and HOHV groups, OHV presented good linearity with T2w, S23, and STotal of relaxation property with correlation coefficient of >0.90. EV and POHV also presented good linearity with relaxation property in both LOHV and HOHV groups. In LOHV group, data segment 1–1000 ms was taken with Deresolve, no preprocessing, and Deresolve as preprocessing methods for OHV, EV, and POHV, respectively, and partial least square (PLS) as the modeling method for all the three indicators, where RMSEPs of OHV, EV, and POHV models were 4.282, 0.114, and 4.061, respectively. In HOHV group, data segment 1–1000 ms was taken with no preprocessing as the preprocessing method and PLS as the modeling method for all the three indicators, where RMSEPs of OHV, EV, and POHV models were 3.117, 0.088, and 4.964, respectively. The established method will benefit polyol industry to online adjust the production parameters according to the monitoring results and achieve high‐quality of vegetable oils‐based polyols.

Development of a gradient method for sulfamethoxazole, trimethoprim, isoniazid, and pyridoxine hydrochloride in rabbit plasma through QbD-driven investigation

The current study developed a method for quantifying four drugs—Sulfamethoxazole, Trimethoprim, Isoniazid, and Pyridoxine—in rabbit plasma. The method uses gradient liquid chromatography based on analytical quality by design. To achieve separation, a Eclip Plus C18 (250 mm × 5 mm, 4.6 µm) column with L1 packing was used, and analytes were detected at 254 nm at ambient temperature. The optimized mobile phase consisted of 50 mM potassium dihydrogen phosphate buffer (pH 6.5) and Methanol. The concentration of Methanol was 3% (0–5 min), 15% (5–15 min), 55% (15–27 min), and 3% Methanol until the end of the 30-min runtime, and the flow rate was set at 0.95 mL/min. Control Noise Experimentation was used to screen studies, revealing that flow rate, pH, and Methanol concentration significantly affected the analytical attributes. The study identified critical attributes (resolution and asymmetric factor) and developed a quality target method profile. A central composition design was used to optimize the essential parameters. The method developed for the drugs showed peaks at retention times of 6.990 min for Isoniazid, 7.880 min for Pyridoxine, 15.530 min for Sulfamethoxazole, and 26.890 min for Trimethoprim, respectively. The method was validated with linearity in the range of 10–640 ng ml−1, with R2 of 0.9993, 0.9987, 0.9993, and 0.9992 for Sulfamethoxazole, Trimethoprim, Isoniazid, and Pyridoxine, respectively.

Macrophage Membrane-Coated Nanoparticles for the Delivery of Natamycin Exhibit Increased Antifungal and Anti-Inflammatory Activities in Fungal Keratitis.

This study aims to explore the efficacy and safety of macrophage membrane-coated nanoparticles for the delivery of natamycin (NAT) in the therapy of fungal keratitis (FK). Macrophage membranes were isolated and identified by immunofluorescence staining (IFS). NAT was encapsulated into poly(lactic-co-glycolic acid) (PLGA). Fungal stimulated macrophage membranes (M1) or unstimulated membranes (M) were separately mixed and sonicated with PLGA nanoparticles. The biocompatible nanoparticles (PLGA-NAT, PLGA-NAT@M, and PLGA-NAT@M1) were characterized with zeta-sizer analysis, transmission electron microscopy (TEM), and Western blot. Drug encapsulation and loading efficiency and the release of NAT in the nanoparticles were detected by ultraviolet spectrophotometry. The cytotoxicity, ocular surface toxicity and irritability, and systemic safety of nanoparticles with different concentrations were assessed. In vitro, we examined the antifungal properties of the nanoparticles. The eye surface retention time, drug release, and curative effects on FK were evaluated in vitro and in vivo. IFS results showed the separation of the macrophage membrane and nucleus. The prepared nanoparticles had a typical "core-shell" structure and uniform nanometer size, and the membrane proteins were retained on the membrane allowing to exert functional effects of macrophage. The loading efficiencies of PLGA-NAT@M and PLGA-NAT@M1 were 7.6 and 6.7%, respectively. The encapsulation efficiencies of PLGA-NAT@M and PLGA-NAT@M1 were 51.2 and 41.5%, respectively. PLGA-NAT@M and PLGA-NAT@M1 could gradually release NAT and reduce the clearance of the ocular surface. Macrophage membranes enhanced the antifungal activity of PLGA-NAT. Furthermore, the membrane coated with macrophage increased the biocompatibility and decreased the corneal toxicity of nanoparticles. In vivo, PLGA-NAT@M1 significantly alleviated the severity of FK. In vitro, PLGA@M and PLGA@M1 reduced the protein levels of inflammatory cytokines after fungal stimulation. The prepared PLGA-NAT@M1 has good physical properties and biosafety. It could evade ocular surface clearance, release NAT gradually, and achieve high antifungal and anti-inflammatory efficiencies to FK. Macrophage membrane-coated nanoparticles clinically have high application potential to the treatment of FK.

Scalable fabrication of vertically arranged Bi2Se3 crossbar arrays for memristive device applications

Despite the unique advantages of the memristive switching devices based on two-dimensional (2D) transition metal dichalcogenides, scalable growth technologies of such 2D materials and wafer-level fabrication remain challenging. In this work, we present the gold-assisted large-area physical vapor deposition (PVD) growth of Bi2Se3 features for the scalable fabrication of 2D-material-based crossbar arrays of memristor devices. This work indicates that gold layers, prepatterned by photolithography processes, can catalyze PVD growth of few-layer Bi2Se3 with 100-folds larger crystal grain size in comparison with that grown on bare Si/SiO2 substrates. We also present a fluid-guided growth strategy to improve growth selectivity of Bi2Se3 on Au layers. Through the experimental and computational analyses, we identify two key processing parameters, i.e., the distance between Bi2Se3 powder and the target substrate and the distance between the leading edges of the substrate and the substrate holder with a hollow interior, which plays a critical role in realizing large-scale growth. By optimizing these growth parameters, we have successfully demonstrated cm-scale highly-selective Bi2Se3 growth on crossbar-arrayed structures with an in-lab yield of 86%. The whole process is etch- and plasma-free, substantially minimizing the damage to the crystal structure and also preventing the formation of rough 2D-material surfaces. Furthermore, we also preliminarily demonstrated memristive devices, which exhibit reproducible resistance switching characteristics (over 50 cycles) and a retention time of up to 106 s. This work provides a useful guideline for the scalable fabrication of vertically arranged crossbar arrays of 2D-material-based memristive devices, which is critical to the implementation of such devices for practical neuromorphic applications.

Metabolomics of Chinese Hamster Ovary Cells.

Increasing demand of protein biotherapeutics produced using Chinese hamster ovary (CHO) cell lines necessitates improvement in the production yield of the bioprocess. Various cell engineering, improved media formulation and process-designbased approaches utilizing the power of OMICS technologies, specifically, genomics and proteomics, have been employed; however, the potential of metabolomics largely remains unexplored. Metabolomics enables the detection, identification, and/or quantitation of small molecules, commonly known as metabolites, in and around the cells and may help to unlock the cellular molecular mechanism(s) that regulates cell growth and productivity in the bioprocess and improves cellular performance during the bioprocess. Currently, liquid chromatography (LC)/gas chromatography (CG)- coupled with mass-spectrometry (MS) and nuclear magnetic resonance (NMR) spectroscopy are the most commonly used approaches for metabolomics. Therefore, in this chapter, we have discussed the standard procedures of investigating CHO metabolites using LC/GC-MS and/or NMR-based approaches.

Responsive Hydrogel-Based Drug Delivery Platform for Osteoarthritis Treatment

Osteoarthritis (OA) is the most prevalent chronic joint disorder and is a major cause of disability among the elderly population. The degeneration and damage of articular cartilage associated with OA can result in a diminished range of motion in joints, subsequently impacting fundamental activities such as ambulation, standing, and grasping objects. In severe cases, it may culminate in disability. Traditional pharmacological treatments are often accompanied by various side effects, while invasive surgical procedures increase the risk of infection and thrombosis. Consequently, identifying alternative new methods for OA treatment remains a formidable challenge. With advancements in responsive hydrogel drug delivery platforms, an increasing number of strategies have emerged to enhance OA treatment protocols. Injectable response hydrogel drug delivery platforms show many advantages in treating OA, including improved biocompatibility, prolonged drug release duration, elevated drug loading capacity and enhanced sensitivity. This article reviews the recent progress of injectable responsive hydrogel drug delivery platform for OA treatment over the past few years. These innovative methodologies present new strategies and directions for future OA treatment while summarizing a series of challenges faced during the clinical transformation of injectable response hydrogel drug delivery platforms. Overall, injectable responsive hydrogel drug delivery platforms show great potential in treating OA, especially regarding improving drug retention time and stimulus-responsive release at the lesion sites. These innovative methods provide new hope for future OA treatment and point the way for clinical applications.

A New Feasible Opportunity for Recycling Lead and Silver from Zinc Plant Residues by Flotation

Millions of tons of zinc plant leach residues (ZPLR) have been stockpiled in Iranian hydrometallurgical zinc plants during the last few decades. Due to the low grades of zinc, lead, and silver in these residues, these residues have been abandoned without treatment. The authors of this paper studied zinc plant leach residues (ZPLR) to propose a flotation process for separating and producing lead and silver concentrate. A response surface methodology (RSM) was employed to obtain six models for optimizing the best conditions for lead recovery, lead grade, zinc recovery, zinc grade, silver recovery, and silver grade. In these models, the effect of the different main variables, including density, flotation time, pH, sodium sulfide dosage, and potassium amyl xanthate dosage, was investigated to optimize grades and recoveries. The studied ZPLRs were categorized into two types based on the disposal time, including new and old residues. The chemical analysis showed that the grades of lead, zinc, and silver in the new residues are higher than in the old residues. In a previous mineralogical study, it was found that silver forms in lead and zinc minerals as a solid solution within their structures. The resulting 3D graphs showed that the interacting variables have significant effects on responses. The ANOVA analysis exhibited the order of model significance to be lead grade (F-value of 36.46) > silver grade (19.76) > lead recovery (7.88) > zinc grade (5.63) > silver recovery (5.58) > zinc recovery (4.83). Based on these models, under the conditions of 1126.26 g/cm3 density, 20.83 min retention time, 9.9 pH, 6 kg/t sodium sulfide, and 749.66 g/t potassium amyl xanthate dosage for a new residue type, the recoveries of lead, zinc, and silver were determined to be 51.10%, 11.13%, and 72.85%, with grades of 38.87% Pb, 8.46% Zn, and 1209.11 g/t Ag, respectively. According to the feasibility study results, the presented work is reasonable in terms of technical, economic, and investment potential.

Kinetics of dietary fibers in a fat sand rat: importance of the digestive tract isolating structures and food quality

The pass of feed through the digestive tract in a herbivorous rodent with a single-chamber gemiglandular stomach, the fat sand rat Psammomys obesus, was studied by multiple marking of the food with inert plastic markers. The total mean retention time of markers in the digestive tract (DT), as well as in the stomach and caecum separately, was determined. The peculiarities of the digesta kinetics depending on the morphology of the digestive tract, diet and the time of markers intake were clarified. The total time for removing markers from DT in the fat sand rat reaches 36 hours. The mean retention time of markers in DT was determined as a whole (17–18 hours), as well as separately in the forestomach (7–9 hours) and caecum (7–12 hours). The uneven passage of feed has been revealed, which is considered as an important mechanism for maximizing the extraction of nutrients from plants, including microbial fermentation of structural carbohydrates of the food.

Intravenous administration of gold nanoparticles in rats exhibit alterations in sphingomyelins, bile acids, sphingolipids, and cholesterol esters levels

AbstractNanoparticles (NP) have gained significant attention in biomedical research due to their unique properties and potential applications in drug delivery, imaging, and diagnostics. Gold (AuNPs) and silver (AgNPs) NPs are among the important nanoplatforms that received extensive attention recently for various biomedical applications. Understanding the complex interaction of these NP in biological systems is essential to unveil their pharmacological, Pharmacokinetic and toxicological attributes. Metabolomics has proven invaluable in providing detailed insights into NP’s biodistribution, metabolic effects, and potential toxicity. This study aims to investigate the underlying metabolic pathways affected by in vivo exposure to NP using a robust metabolomics approach. In this work, spherical polyethylene glycol (PEG) modified AuNPs (13 nm, diameter) or AgNPs (20 nm, diameter) were synthesized and dosed into rats via intravenous route to study the associated metabolic changes. Rats (n = 14) were divided into three groups: control (n = 2), AuNPs (n = 6) and AgNPs (n = 6), to mimic potential biomedical exposure scenarios. Duplicate serum samples were collected 24 h post-dosing, and comprehensive metabolite profiling was performed using liquid chromatography-mass spectrometry (LC-MS/MS) and flow injection analysis-mass spectrometry (FIA-MS/MS). Metabolite extraction followed the MxP Quant 500 Kit protocol, with chromatographic separation using the Xevo TQS system. Metabolite identification and quantification were conducted with isotopically labelled internal standards and multiple reaction monitoring (MRM), utilizing optimized conditions under mass spectrometry (MS) as provided by Biocrates. Annotation of metabolites was determined by retention times and specific MRMs for each compound. Results indicate that AuNPs treatment significantly impacted several metabolic pathways. Notably, there was an increase in sphingomyelin (SM 34:2) levels (estimate 0.23, p ≤ 0.001), which are critical for cell membrane structure and signalling. Additionally, a decrease in glycochenodeoxycholic acid levels was also triggered by treatment with AuNPs, suggesting modulation of bile acid metabolism with potential effects on lipid homeostasis. Furthermore, treatment with AuNPs caused significant alterations in cholesterol ester levels, essential for lipid storage and transport, indicating disruptions in these mechanisms. These metabolic changes suggest that gold nanoparticles can disrupt fatty acid metabolism, pyrimidine/purine metabolism, and amino acid synthesis. These findings contribute to the growing understanding of nanoparticle toxicity profile and underscore the need for further research to ensure the safe application of nanoparticles in biomedical and other fields.

Development of microflow ultra high performance liquid chromatography-mass spectrometry metabolomic assays for analysis of mammalian biofluids

Introduction and objectivesThe application of untargeted metabolomics assays using ultra high performance liquid chromatography-mass spectrometry (UHPLC-MS) to study metabolism in biological systems including humans is rapidly increasing. In some of these studies there is a requirement to collect and analyse low sample volumes of biofluids (e.g. tear fluid) or low cell and tissue mass samples (e.g. tissue needle biopsies). The application of microflow, capillary or nano liquid chromatography (≤ 1.0 mm column internal diameter (i.d.)) theoretically should accomplish a higher assay sensitivity compared to analytical liquid chromatography (2.1–5.0 mm column internal diameter). To date, there has been limited research into microflow UHPLC-MS assays that can be applied to study samples of low volume or mass.MethodsThis paper presents three complementary UHPLC-MS assays (aqueous C18 reversed-phase, lipidomics C18 reversed-phase and Hydrophilic Interaction Liquid Chromatography (HILIC)) applying 1.0 mm internal diameter columns for untargeted metabolomics. Human plasma and urine samples were applied for the method development, with porcine plasma, urine and tear fluid used for method assessment. Data were collected and compared for columns of the same length, stationary phase and stationary phase particle size but with two different column internal diameters (2.1 mm and 1.0 mm).Results and conclusionsAll three assays showed an increase in peak areas and peak widths when applying the 1.0 mm i.d. assays. HILIC assays provide an advantage at lower sample dilutions whereas for reversed phase (RP) assays there was no benefit added. This can be seen in the validation study where a much higher number of compounds were detected in the HILIC assay. RP assays were still appropriate for small volume samples with hundreds of compounds being detected. In summary, the 1.0 mm i.d. column assays are applicable for small volume samples where dilution is required during sample preparation.

Rapid QC-MS: Interactive Dashboard for Synchronous Mass Spectrometry Data Acquisition Quality Control.

Consistently collecting high-quality liquid chromatography-coupled tandem mass spectrometry (LC-MS/MS) data is a time-consuming hurdle for untargeted workflows. Analytical controls such as internal and biological standards are commonly included in high-throughput workflows, helping researchers recognize low-integrity specimens regardless of their biological source. However, evaluating these standards as data are collected has remained a considerable bottleneck─in both person-hours and accuracy. Here we present Rapid QC-MS, an automated, interactive dashboard for assessing LC-MS/MS data quality. Minutes after a new data file is written, a browser-viewable dashboard is updated with quality control results spanning multiple performance dimensions such as instrument sensitivity, in-run retention time shifts, and mass accuracy drift. Rapid QC-MS provides interactive visualizations that help users recognize acute deviations in these performance metrics, as well as gradual drifts over periods of hours, days, months, or years. Rapid QC-MS is open-source, simple to install, and highly configurable. By integrating open-source Python libraries and widely used MS analysis software, it can adapt to any LC-MS/MS workflow. Rapid QC-MS runs locally and offers optional remote quality control by syncing with Google Drive. Furthermore, Rapid QC-MS can operate in a semiautonomous fashion, alerting users to specimens with potentially poor analytical integrity via frequently used messaging applications. Initially developed for integration with Thermo Orbitrap workflows, Rapid QC-MS offers a fast, straightforward approach to help users collect high-quality untargeted LC-MS/MS data by eliminating many of the most time-consuming steps in manual data curation. Download for free: https://github.com/czbiohub-sf/Rapid-QC-MS.

The Fabrication of Polyimide-Based Tunable Charge Traps Ternary Memristors Doped with Ni-Co Coated Carbon Composite Nanofibers

In the dynamic fields of information science and electronic technology, there is a notable trend towards leveraging carbon materials, favored for their ease of synthesis, biocompatibility, and abundance. This trend is particularly evident in the development of memristors, benefiting from the unique electronic properties of carbon to enhance device performance. This study utilizes sensitized chemical evaporation and spin-coating carbonization techniques to fabricate nickel-cobalt coated carbon composite nanofibers (SC-NCMNTs). Novel polyimide (PI) matrix composite memory devices were fabricated using in situ polymerization technology. Transmission electron microscopy (TEM) and micro-Raman spectroscopy analyses validated the presence of dual interface structures located between the Ni-Co-MWNTs, carbon composite nanofibers, and PI matrix, revealing a significant number of defects within the SC-NCMNTs/PI composite films. Consequently, this results in a tunable charge trap-based ternary resistive switching behavior of the composite memory devices, exhibiting a high ON/OFF current ratio of 104 and a retention time of 2500 s at an operating voltage of less than 3 V. The mechanism of resistive switching is thoroughly elucidated through a comprehensive charge transport model, incorporating molecular orbital energy levels. This study provides valuable insights for the rational design and fabrication of efficient memristors characterized by multilevel resistive switching states.

Chromatographic Determination of Permeability-Relevant Lipophilicity Facilitates Rapid Analysis of Macrocyclic Peptide Scaffolds.

Hydrocarbon-determined shake-flask measurements have demonstrated great utility for optimizing lipophilicity during early drug discovery. Alternatively, chromatographic methods confer reduced experimental error and improved handling of complex mixtures. In this study, we developed a chromatographic approach for estimating hydrocarbon-water shake-flask partition coefficients for a variety of macrocyclic peptides and other bRo5 molecules including PROTACs. The model accurately predicts experimental shake-flask measurements with high reproducibility across a wide range of lipophilicities. The chromatographic retention times revealed subtle conformational effects and correlated with the ability to sequester hydrogen bond donors in low dielectric media. Estimations of shake-flask lipophilicity from our model also accurately predicted trends in MDCK passive cell permeability for a variety of thioether-cyclized decapeptides. This method provides a convenient, high-throughput approach for measuring lipophilic permeability efficiency and predicting passive cell permeability in bRo5 compounds that is suitable for multiplexing pure compounds or investigating the properties of complex library mixtures.