Short Separation Time Research Articles

Evaluation and Comparison of UiO66 and Its Functionalized Variants for the Removal of Cu (II) Ions from Wastewater

This study examined the effectiveness of polyvinyl chloride (PVC) mixed matrix membranes incorporating UiO66 and UiO66-NH2 metal-organic frameworks (MOFs) for removing varying concentrations of Cu (II) ions from wastewater. The findings indicated that adding UiO66-NH2 to the functionalized UiO (FUiO) membrane enhanced its porosity, pore size, hydrophilicity, and pure water flux. Furthermore, integrating UiO66-NH2 into the PVC matrix led to an impressive Cu (II) ion removal efficiency exceeding 99%. The PVC-FUiO2 membrane also demonstrated about 93.5% reusability after the first cycle. Overall, the results confirmed that the PVC-FUiO2 (Functionalized UiO66) membrane exhibited superior performance in terms of Cu (II) removal efficiency and shorter separation times across various Cu (II) concentrations compared to the unmodified membrane.

Preparation of highly active MgO by carbonate hydrogenation and its application in separation of cobalt and nickel

AbstractAs a significant industrial material, MgO is mainly obtained by the pyrolysis of magnesite (magnesium carbonate) under air conditions, producing large amounts of CO2 and contributing to global warming. In this work, the MgO was prepared using the hydrogenation reduction method. The reaction conditions led to CO2 emissions of <1% and an overall temperature decrease of ~80°C. The highly active MgO prepared by hydrogenation reduction led to a precipitation rate of Co and Ni >99% with a short separation time. Electron paramagnetic resonance, CO2 temperature programmed desorption, and diffuse reflectance infrared spectroscopy analyses showed that the MgO prepared by hydrogenation contained oxygen vacancies, which improved the alkalinity of the MgO and promoted the precipitation of Ni2+ and Co2+ by adsorption of hydroxyl oxygen to induce water dissociation, thereby enhancing their separation efficiency.

A new DES-mediated synthesis of Henna-based benzopyranophenazines and benzoxanthenetriones

MTPPBr/THFTCA-DES was prepared as a new deep eutectic solvent (DES) from a mixture (molar ratio 7:3) of methyltriphenyl-phosphonium bromide (MTPPBr) and tetrahydrofuran-2,3,4,5-tetra-carboxylic acid (THFTCA), and characterized with various spectroscopic techniques, densitometer, and eutectic point. Then, it was used as a new and powerful catalyst for the synthesis of two sets of biologically important compounds, namely the Henna-based benzopyranophenazines and benzoxan-thenetriones. Solvent-free conditions, short reaction time, high efficiency, and easy recycling and separation of the DES catalyst are among the most important features of the presented method. Also, there is a nice consistency between the proposed structure of the DES compound, the integration values of the 1H NMR peaks, and the ratio of MTPPBr to THFTCA obtained from the eutectic point phase diagram. In addition, the reduction of peak splitting patterns in DES compared to the two primary materials can be good evidence of the formation of hydrogen bonds between the two components.

The new phthalic acid-based deep eutectic solvent as a versatile catalyst for the synthesis of pyrimido[4,5-d]pyrimidines and pyrano[3,2-c]chromenes

A new DES (MTPPBr-PHTH-DES) was prepared from a mixture of methyltriphenyl-phosphonium bromide (MTPPBr) and phthalic acid (PHTH). The eutectic point phase diagram showed that a one-to-one molar ratio of MTPPBr to PHTH is the optimal molar ratio for the synthesis of new DES. Then, it was characterized with various techniques such as FT-IR, TGA/DTA, densitometer, eutectic point, and NMR and used as a novel acid catalyst in the synthesis of pyrimido[4,5-d]pyrimidines and pyrano[3,2-c]chromes in solvent-free condition. Short reaction time, low temperature, high efficiency, green condition, and easy recycling and separation of the DES catalyst are among the most important features of the presented method.

Zn complexed on hybrid manganese doped cobalt ferrite nanoparticles covered by silica as a catalyst in the synthesis of 2-amino-4H-pyran and N- arylquinoline derivatives

In the present work, Zn complexed on hybrid manganese doped cobalt ferrite nanoparticles covered by silica were synthesized. These MNPs were characterized using different techniques including Fourier-transform infrared spectroscopy (FT-IR), X-ray diffraction analysis (XRD), Field emission‐scanning electron micro-scope (FE-SEM), Energy‐dispersive X‐ray spectroscopy (EDS), Vibration sample magnetometer (VSM), Inductively coupled plasma atomic emission spectroscopy (ICP), Zeta potential and Thermogravimetric analysis (TGA). FE-SEM Images showed uniform spherical shape with rough surfaces and an aggregation in structure of MNPs. A decrease in Ms is visible in VSM analysis due to the increase in particle diameter as a result of loading the organic coating on the surface of the magnetic nanoparticles. According to TGA analysis, the synthesized MNPs have good stability up to 125 °C. The ICP analysis indicates the presence of 0.13 mmol/g zinc on the surface of loaded MNPs. The effect of these prepared MNPs as a catalyst was studied in the synthesis of 2-amino-4H-pyran and N- arylquinoline derivatives. This method provides excellent yield of products with short reaction time, simple purification and easy separation of the catalyst. Furthermore, the reusability of the catalyst during five periods was not associated with a significant decrease in its activity.

Phase-encoding of loosely bound soliton molecules

Dissipative soliton molecules (DSMs) are of great interest for studying the complexity of nonlinear optical problems as they can map with the matter molecules for making interdisciplinary analogies. In contrast to strongly bound DSMs that have a short time separation between the bound solitons, the complex dynamics and underlying binding mechanism of loosely bound soliton molecules (LBSMs) with orders of magnitude longer time separation remain open questions. To this end, here, we explore real-time spectroscopy using a dispersive temporal interferometer (DTI) to visualize the dynamics of LBSMs in a mode-locked fiber laser and unveil their underlying phase-evolving mechanism. The DTI enables fringe-resolved spectroscopy in real time of the LBSM’s evolution by creating duplicates of the LBSM that results in a much closer time separation between the individual solitons of the LBSM. The real-time evolution of the LBSM’s phase exhibits a diverging sliding landscape, which is theoretically and experimentally proved to be closely associated with gain dynamics. Based on the understanding of its phase dynamics, we finally demonstrate programmable phase-encoding modulation of the LBSM through gain control. These efforts not only shed light on understanding the mechanism of long-range interactions in LBSMs but also provide an alternative approach for all-optical information processing.

Hierarchical Dendritic Photonic Crystal Beads for Efficient Isolation and Proteomic Analysis of Multiple Cell Types.

Cell types with different morphology, and function collaborate to maintain organ function. As such, analyzing proteomic differences and connections between different types of cells forms the foundation for establishing functional connectomes and developing in vitro organoid simulation experiments. However, the efficiency of cell type isolation from organs is limited by time, equipment, and cost. Here, hierarchical dendritic photonic crystal beads (HDPCBs) featuring high-density functional groups via the self-assembly of dendritic mesoporous structure SiO2 nanoparticles (DM-SiO2) and grafting dendrimers onto the surface of dendritic mesoporous photonic crystal beads (DMPCBs) is developed. This platform integrates multitype cell separation with in situ protein cleavage processes. Efficient simultaneous isolation of Kupffer cells and Liver Sinusoidal Endothelial cells (LSECs) from liver, with high specificity and convenient operation in a short separation time are demonstrated. The results reveal 2832 and 3442 unique proteins identified in Kupffer cells and LSECs using only 50 HDPCBs, respectively. 764 and 629 over-expressed proteins associated with the function of Kupffer cells and LSECs are found, respectively. The work offers a new method for efficiently isolating multiple cell types from tissues and downstream proteomic analysis, ultimately facilitating the identification of primary cell compositions and functions.

The first 30 min hidden aftershocks of the 2022 September 17, ML 6.4, Guanshan, Taiwan earthquake and its seismological implications

The first 30 min of the aftershock sequence following the 2022 September 17, ML 6.4, Guanshan, Taiwan earthquake is investigated by the back-projection (BP) method. Based on the Automatic Gain Control (AGC) to process individual earthquake record and sort waveforms by epicentral distance, 80 events are identified near the Guanshan earthquake epicenter to verify its temporal variation. However, most of these events cannot clearly image by the BP method to determine its spatial locations for its small amplitude and short time separation. In total, 29 aftershocks are imaged by this study to identify its spatial locations during this time period. The relocated events are compared with the Central Weather Bureau (CWB) rapid report catalogue. Only 5 events have been reported by the CWB rapid report catalogue. These unreported hidden aftershocks are identified to distribute surrounding the epicenter and extended to the east. This extracted information of hidden aftershocks is crucial for assessing the potential for future large aftershocks and estimating the associated seismic hazards in a given region, and provide extra message to evaluate the source physics in general.

Chiral LC-MS/MS method development for the enhanced separation and determination of pranoprofen enantiomers and its application to a stereoselective pharmacokinetic study

The objective of this study is to develop a quick and precise chiral liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) technology that operates in reversed phase mode. Following oral administration of 5.0 mg/kg rac-pranoprofen, the suggested approach was completely validated and successfully used to the stereoselective detection of pranoprofen enantiomers in rat plasma for the first time. Both the polysaccharide derivatized chiral stationary phase and a homemade β-cyclodextrin (β-CD) derivatized based chiral column were assessed. The latter one, a per-4-chlorophenylcarbamate-β-cyclodextrin bonded chiral stationary phase (CPCDP) made in our laboratory, allowed for the highly sensitive detection, relatively short retention time and complete separation (resolution 2.0) of the pranoprofen enantiomers. A solid phase extraction (SPE) procedure on C18 cartridge was optimized for the extraction of S-(+)-, R-(−)-pranoprofen and internal standard (S-(+)-ketoprofen, IS) from rat plasma in detail. Acetonitrile with 0.1 % formic acid in aqueous phase (60:40, v:v) at a flow rate of 0.6 mL/min was the ideal mobile phase condition. The outcome of pharmacokinetic study showed that the values of maximum plasma concentration (Cmax) and the area under plasma drug concentration–time curve to infinity (AUC0-∞) for S-(+)-pranoprofen were 1.79 and 1.90 times greater than R-(−)-isomer, respectively. Altogether, this work is the first to examine the stereospecific pharmacokinetics of pranoprofen enantiomers in vivo, whose data provided potential possibility for the development of pure isomer with superior pharmacological activity and safety to replace racemic application in the clinic.

Conceptual study of a Compton polarimeter for the upgrade of the SuperKEKB collider with a polarized electron beam

The physics scope of the Belle II experiment currently acquiring data at the SuperKEKB collider will expand with a polarized electron beam upgrade, as recently proposed. Among the required elements for this upgrade, a real time diagnosis of the polarization is necessary to ensure it is large for all bunches in the accelerator during its regular operation. This will be realized by inserting a Compton polarimeter in the accelerator. Its conceptual design is described and no show-stopper for its integration has been identified. An estimation of the sensitivity of the polarimeter is made by means of toy Monte-Carlo studies. The proposed design accounts for the constraint to preserve the performance of the SuperKEKB accelerator and to cope with the short time separation of successive bunches. We show that the polarimeter will measure for each bunch the polarization within five minutes with a statistical precision below 1% and systematic uncertainties below 0.5%. It has the capability of providing this information online on a similar timescale. This work paves the way towards future implementation of real-time Compton polarimetry in several future projects.

Countercurrent chromatography separation of vitamin E isomers in a co-current mode.

Vitamin E represents a group of lipophilic phenolic compounds, including α-tocopherol, β-tocopherol, γ-tocopherol, and δ-tocopherol, and α-tocotrienol, β-tocotrienol, γ-tocotrienol, and δ-tocotrienol isomers. Different forms of vitamin E have been proven to exhibit varying biological activities. However, due to their structural similarities, the separation of vitamin E isomers is a challenging task. Therefore, it is crucial to establish an efficient method for isolating individual isomers. In this study, co-current countercurrent chromatography was employed to isolate vitamin E isomers from commercial capsules using a n-heptane-methanol-water (10:9.5:0.5, v/v) solvent system. The partition coefficients of the main constituents in the capsules ranged from 0.94 to 6.23, requiring over 450 min for a complete separation. To improve separation efficiency, a co-current elution mode was implemented and the flow rates of the two liquid phases as well as sample amount were examined. The results suggested that increasing the flow rate of the stationary phase and sample size could result in more effective separation, shorter separation time, and higher yield. It proved that co-current countercurrent chromatography was an effective method for the separation of vitamin E isomers.

Magnetic carbon nanotubes mesoporous silica nanocomposite functionalized with copper: Synthesis, characterization, and application for the efficient catalytic preparation of dihydrano-choromenes

Nanoparticles of Fe3O4 were prepared and immobilized onto the surface of carbon nanotube (CNTs), followed by copper immobilization on the nanoparticles. The resulting MWCNT@Fe3O4@SiO2@CPTMO@DEA/Cu(II) nanocatalysts were characterized using Fourier transform infrared spectroscopy, X-ray diffraction patterns, scanning electron microscopy, energy dispersive X-ray spectroscopy, vibrating sample magnetometer, and thermal gravimetric analysis. The catalyst was then employed for the benign synthesis of 3,4-dihydropyrano[3,2-c]chromene derivatives. The main advantages of this work are high efficiency, short reaction time, simple operation and easy separation of the catalyst from the reaction mixture using an external magnet. The catalyst was magnetically retrieved and reused for six sequential cycles without significant loss of activity or re-selection. Furthermore, this method exhibits superior characteristics, including high efficiency, short reaction time and simple separation operation, compared to traditional dihydropyran-chromene reactions and other methods.

A green yttrium extraction system containing naphthenic acid, trioctyl/decylamine and isopropanol

Yttrium extraction usually produces waste water and suffers from difficulty in phase separation when using saponified naphthenic acid as the extractant. Herein, a non-saponified mixed extraction system containing naphthenic acid, trioctyl/decylamine and modifier was developed for yttrium extraction. Unlike the traditional saponified naphthenic acid system using long chain alcohol as the modifier, short chain alcohol of isopropanol was introduced into the extraction system for the first time. When using 20 vol% naphthenic acid, 40 vol% trioctyl/decylamine, 10 vol% sec-octyl alcohol and 25 vol% isopropanol diluted in 5 vol% n-hexane as extractant, a high yttrium extraction efficiency of above 60% could be obtained within a short phase separation time of ∼5 min. The yttrium separation from other rare earth elements could be achieved through two steps of LaCePrNdY/GdSmEuTbDyHoErTmLuYb grouping extraction followed by LaCePrNd/Y separation. Trioctyl/decylamine, sec-octyl alcohol and isopropanol showed the synergistic extraction effect with naphthenic acid, among which isopropanol was the strongest, followed by trioctyl/decylamine and sec-octyl alcohol. Trioctyl/decylamine could extract H+ produced from naphthenic acid, and isopropanol and/or sec-octyl alcohol could bond with naphthenic acid via hydrogen-bond interaction to prevent the formation of naphthenic acid dimers, leading to more coordination sites exposed for yttrium extraction. Furthermore, isopropanol and/or sec-octyl alcohol participated in the coordination in the extracted organic compound. The combination of the above three action had great contribution to the high extraction efficiency and the rapid phase separation. There was no waste water produced during extraction. Therefore, the proposed mixed system is a green and efficient system for yttrium extraction.

SFC and CE—A Comparison of Two Orthogonal Methods for the Analysis of Dihydrochalcones in Apple Leaves

In recent years the analysis of natural products has been carried out using a range of approaches, but mainly utilizing liquid chromatography (LC) or gas chromatography (GC). However, alternative approaches with orthogonal selectivity like capillary electrophoresis (CE) and supercritical fluid chromatography (SFC) have increasingly been employed as well, even though they are often considered niche techniques only. In this study, we intended to confirm and compare their suitability as reliable state-of-the-art methods for the analysis of bioactive compounds by developing CE and SFC for the analysis of dihydrochalcones (DHCs) in apple leaves. The analytes were chosen as they have shown interesting pharmacological effects, such as anti-inflammatory, anti-tumor and immunomodulatory activities, and also present an interesting analytical challenge due to their structural similarity and polarity range. Both methods were well capable to separate the five standard compounds within short separation times and fulfilling the demands for an environmentally friendly “green” technology. CE as well as the SFC assay were validated for linearity, sensitivity, accuracy and precision according to ICH guidelines and met all respective requirements. Using the optimized methods, several Malus sp. samples were analyzed whereby a significant difference in the qualitative as well as quantitative DHC profile was revealed, with overall DHC concentrations ranging from 5.47% to 17.24%.

Chromatographic method development using multivariate approaches for organic solvents optimized analysis in [18F]fluorocholine

A fast and simple method using Gas Chromatography combined with Flame Ionization Detection (GC-FID) was developed for the determination of ethanol, acetonitrile, dibromomethane, dimethylaminoethanol, and dimethyl sulfoxide in [18F]fluorocholine. The combination of fractional factorial design, Doehlert design, and Desirability function was used to evaluate the operational parameters and to establish the best working condition. The validation results revealed that the proposed method has good recovery (85.1–104.1%) and repeatability (RSD ≤8.1%). Correlation coefficients (R ≥ 0.983) indicated good linearity over a wide range. The limit of detection (≤2.5 ppm) and the limit of quantification (≤7.5 ppm) were satisfactory. The proposed method is based on minimum manual operation, sample preparation free, direct injection technique, and short chromatographic separation time. This method is useful for routine analysis of organic solvents in [18F]fluorocholine, feasible for the modernization of specific monograph, and was therefore successfully implemented to assess samples manufactured by Nuclear Technology Development Center (CDTN).

H2/D2 Separation Using UTSA-16@CAU-10-H@γ-AlOOH Composites as the Stationary Phase in Gas Chromatography via the Additive Effects of Kinetic Sieving and Chemical Affinity Quantum Sieving.

In this work, CAU-10-H@γ-AlOOH is prepared, and then UTSA-16 is loaded on CAU-10-H@γ-AlOOH to obtain UTSA-16@CAU-10-H@γ-AlOOH. Using the as-prepared composites as stationary materials by cryogenic gas chromatography at 77 K, while CAU-10-H@γ-AlOOH achieves the complete separation of ortho-H2 (o-H2) and D2 with a resolution R of 1.66 and a separation time t of 9.52 min, UTSA-16@CAU-10-H@γ-AlOOH achieves higher efficiency separation of hydrogen isotopes in a shorter separation time (4.56 min) with R = 1.7. Molecular simulation results show that CAU-10-H has both chemical affinity quantum sieving and kinetic sieving effects for H2/D2 at 77 K, and UTSA-16 can only exert the kinetic sieving effect. UTSA-16's load on CAU-10-H@γ-AlOOH weakens the adsorption of hydrogen isotopes, and the presence of Co2+ in UTSA-16 promotes the conversion of para-H2 to ortho-H2. In gas chromatography, H2 was preferentially desorbed from the system due to strong D2 adsorption caused by the chemical affinity quantum sieving effect and faster H2 diffusion caused by the kinetic sieving effect. These additive effects achieved efficient hydrogen isotope separation at 77 K.

Gradient mapping of multi-timescale optical coherence tomography angiography signals for enhancing signal-to-noise ratio of flow detection

Optical coherence tomography (OCT) is a three-dimensional imaging technique based on low coherence interferometry of near-infrared broadband light and has been applied to medical diagnoses, such as structural diagnosis of the retina in ophthalmology. For several decades, functional variations of OCT have been also developed. OCT angiography (OCTA) is one of the functional variations of OCT and can visualize blood flows (microvasculature) in biological tissues by analyzing the time-series of OCT signals. Recently, several studies suggested the possibility that OCTA can not only visualize blood flows but also detect the blood flow velocity quantitatively, where the blood flow velocity is estimated by analyzing OCTA signals computed with multiple time separations from the time-series of OCT signals measured at a short time interval. OCTA signals computed with short time separations, however, reduce its contrast between dynamic tissues (blood flows) and other static tissues, resulting in the decrease of signal-to-noise (SN) ratio of the flow detection. This study proposed a novel method to enhance the SN ratio of the flow detection from such OCTA signals computed with short time separations, by means of mapping the gradient of OCTA signals against the time separations. In the experiments, a flow phantom and human skins were employed to compare SN ratios among OCTA with a long time separation (standard OCTA), OCTA with a short time separation, and the proposed method. The results showed that the proposed methods can detect flow signals with a high SN ratio equivalent to that of the standard OCTA and, therefore, suggested that quantitative detection of the flow velocity with OCTA will be possible with a high SN ratio of flow detection.

Increase the flow rate and improve hydrogen deuterium exchange mass spectrometry

Reversed-phase peptide separation in hydrogen deuterium exchange (HDX) mass spectrometry (MS) must be done with conditions where the back exchange is the slowest possible, the so-called quench conditions of low pH and low temperature. To retain maximum deuterium, separation must also be done as quickly as possible. The low temperature (0 °C) of quench conditions complicates the separation and leads primarily to a reduction in separation quality and an increase in chromatographic backpressure. To improve the separation in HDX MS, one could use a longer gradient, smaller particles, a different separation mechanism (for example, capillary electrophoresis), or multi-dimensional separations such as combining ion mobility separation with reversed-phase separation. Another way to improve separations under HDX MS quench conditions is to use a higher flow rate where separation efficiency at 0 °C is more ideal. Higher flow rates, however, require chromatographic systems (both pumps and fittings) with higher backpressure limits. We tested what improvements could be realized with a commercial UPLC/UHPLC system capable of ∼20,000 psi backpressure. We found that a maximum flow rate of 225 µL/min (using a 1 × 50 mm column packed with 1.8 µm particles) was possible and that higher flow rate clearly led to higher peak capacity. HDX MS analysis of both simple and particularly complex samples improved, permitting both shorter separation time, if desired, and providing more deuterium recovery.

Syntheses and Characterization of Tetrazolate-Based Lanthanide Compounds and Selective Crystallization Separation of Neodymium and Dysprosium.

Selective crystallization offers new opportunities for separating neodymium and dysprosium, which are considerably important in permanent magnets. Two water-soluble nitrogen-rich tetrazolate-based ligands, dtp2- (H2dtp = 2,3-di-1H-tetrazol-5-ylpyrazine) and H2ibt- [H3ibt = 4,5-bis(tetrazol-5-yl)imidazole], allow the separation of Nd3+ and Dy3+ through selective crystallization. The reactions of Ln3+ with the ligand Na2(dtp)·2H2O lead to two distinct phases, Na[Ln(dtp)(H2O)8](dtp)·H2O (Lndtp1; Ln = La-Pr) and [Ln(H2O)8](Hdtp)(dtp)·H2O (Lndtp2; Ln = Nd and Sm-Lu). Three different compound types, [Ln(H2ibt)2(H2O)6](H2ibt)·3(H2O) (Lnibt1; Ln = La or Ce), [Ln(H2ibt)(H2O)7](H2ibt)2·4(H2O) (Lnibt2; Ln = Pr or Nd), and [Ln(Hibt)(H2ibt)(H2O)4]·4+x(H2O) (Lnibt3; Ln = Sm-Lu), are obtained from reacting Ln3+ and Na(H2ibt)·3(H2O). Two different phases are observed for Nd(Lnibt2) and Dy(Lnibt3) in the system of H2ibt-, which leads to crystallization-based separation of Nd/Dy with a separation factor of 32 ± 0.7, 10 times higher than that of dtp2-, and a short separation time of 20 s (1 day for dtp2-). The higher performance of H2ibt- compared to that of dtp2- provides guidance for the rational design of water-soluble tetrazolate-derived ligands for selective crystallization.

Multiscale numerical research on nucleate boiling enhancement from microscale to nanoscale

Nucleate boiling enhancement from surfaces in energy industries is of fundamental significance for improving energy conversion and thermal management efficiency. This study investigates the microscale and nanoscale boiling processes on the hybrid wettability micropillar structured surface (MPS) to continuously enhance nucleate boiling. The microscale and nanoscale boiling processes and underlying enhancement mechanisms are studied by Lattice Boltzmann Method (LBM) and Molecular Dynamics (MD) simulations, respectively. It is revealed that MPS designed with a hydrophilic bottom surface and a hydrophobic top surface decorated with nanopillars can improve nucleate boiling throughout the microscale and nanoscale boiling process. The microscopic boiling process of the hybrid wettability MPS shows that the synergistic effect of wettability and surface structure is attributed to nucleation boiling enhancement due to higher bubble nucleation density and higher bubble departure frequency. The nanoscale boiling process on hydrophobic nanopillar structured surfaces (NPS) shows further nucleate boiling enhancement. The NPS with a nanopillar height of 1.6268 nm is in the Wenzel state with higher heat flux and lower thermal resistance, resulting in faster boiling onset and shorter separation time, while the hydrophobic NPSs in the Cassie state leads to a deterioration in the nucleate boiling.