Separation Strategy Research Articles

Spectral domain isolation of ballistic component in visible light OCT based on random matrix description

Visible light optical coherence tomography (vis-OCT) provides a unique tool for imaging both structure and oxygen metabolism in ophthalmology. Working in visible light bandwidth, it suffers from noises due to strong scattering, especially in the blood. This work established the random matrix (RM) description of vis-OCT’s k-space data as ballistic and multiple scattering components. The eigenvalue density of the hybrid RM follows a low-rank biased Marčenko–Pastur law. The ballistic component can thus be separated out using a generalized likelihood ratio test algorithm. The RM-based method was validated by both the Monte Carlo simulation and ex vivo pure blood phantom study. We further demonstrated that the RM-based method could significantly improve the imaging quality in the human fundus, showing more details of the layered structure than current vis-OCT with ∼23.6% increase of signal-to-noise ratio, measuring the blood oxygen value more accurately, and enabling better structure visualization than the traditional method, a 1.6-fold higher contrast-to-noise ratio in raster scan mode. The isolated ballistic component also fits the Beer–Lambert law better, giving more accurate oxygen saturation in arc scan mode. The RM-based method significantly improves the reconstruction quality in 3D and facilitates clinical diagnostics. As a general framework, random matrix description also provides a new separation strategy to estimate the ballistic component in other spectral domain OCT techniques.

Analysis of sperm separation protocols for isolating cryopreserved human spermatozoa.

Sperm cryopreservation is a valuable tool for the long-term preservation of male fertility. Thus, determining the optimal technique for isolating spermatozoa post-thaw is vital to ensure recovery of the highest quality spermatozoa with minimal iatrogenic damage. This not only enhances the chances of successful conception but also reduces the risk of genetic damage in the embryo. To address this issue, human semen samples were cryopreserved using a slow freezing protocol and Quinn's Advantage™ Sperm Freeze medium. The samples were subsequently thawed and subjected to three types of sperm isolation procedures: direct swim-up, density gradient centrifugation, and electrophoretic separation using the Felix™ device. Cryopreservation led to the anticipated loss of sperm motility and vitality in association with increases in lipid peroxidation and DNA damage. Following sperm selection, all three isolation techniques resulted in an increase in sperm motility which was particularly evident with the swim-up and Felix™ procedures. The latter also significantly improved sperm vitality. There were no differences between sperm separation techniques with respect to morphology, and mitochondrial reactive oxygen species generation remained essentially unchanged when cell vitality was taken into account. By contrast, major differences were observed in DNA integrity and lipid aldehyde formation, where Felix™ isolated cells exhibiting significantly less DNA damage than the other isolation procedures as well as lower levels of 4-hydroxynonenal formation. Electrophoretic sperm isolation, therefore, offers significant advantages over alternative separation strategies, in terms of the quality of the gametes isolated and the time taken to achieve the isolation. Long-term storage of sperm is vital to assisted reproductive technology because it permits the preservation of fertility that might be compromised as a result of factors such as chemotherapy or vasectomy. This goal can be achieved via cryopreservation - the freezing of cells to -196°C. When the sperm are subsequently required for conception, they must be carefully separated from the cryopreservation medium in a manner that maximizes the chances of successful conception and minimizes the risk of genetic defects in the offspring. In this paper, three isolation techniques were compared for their ability to separate ideal sperm from semen and media following cryopreservation. It was found that cryopreservation led to lower levels of motility and vitality and created higher levels of DNA and cell membrane damage. Of the three techniques compared, only cells separated on the basis of their size and electric charge (electrophoretic isolation) exhibited significantly lower levels of DNA fragmentation.

Simultaneous Recovery of Bovine Serum Albumin and Bovine Immunoglobulin G with Dual-Ligand Hydrophobic Charge-Induction Chromatography

This study investigated the potential of dual-ligand hydrophobic charge-induction chromatography for the simultaneous recovery of two high-value components (bovine serum albumin and bovine immunoglobulin G). Compared to single-ligand chromatography, dual-ligand chromatography offers greater flexibility and room for improvement. Tryptophan and tryptamine were used as ligands to prepare a series of single- and dual-ligand resins. Bovine serum albumin and bovine immunoglobulin G were used for adsorption and comparison in batch, frontal adsorption, and recovery experiments. The results showed that the dual-ligand mode had a stable coupling efficiency ratio (tryptamine to tryptophan, ∼2.30) during preparation and could break through the upper limit of the adsorption capacity of single-ligand mode. Additionally, it exhibited good adsorption performance for both bovine serum albumin and bovine immunoglobulin G from bovine serum (recoveries of 90.73 and 101.4%, respectively). The findings of this study confirmed that dual-ligand chromatography can be used as an effective strategy for biological separation.

Surfactant-free emulsion of epoxy resin/sodium alginate for achieving robust underwater superoleophobic coating via a combination of phase separation and biomineralization

Underwater superoleophobic coatings exhibit promising prospects in the field of oil contamination resistance. However, their poor durability, stemming from the fragile structures and unstable hydrophilicity, greatly restricted their development. In this report, we proposed a novel strategy of combination water-induced phase separation and biomineralization to prepare the robust underwater superoleophobic epoxy resin-calcium alginate (EP-CA) coating by utilizing a surfactant-free emulsion of epoxy resin/sodium alginate (EP/SA). The EP-CA coating not only exhibited excellent adhesion to various substrates, but also had remarkable resistance to the physical/chemical attacks such as abrasion, acid, alkali and salt. It could also protect the substrate (e.g., PET substrate) from the damage of organic solution and the fouling of crude oil. This report provides a new perspective to fabricate robust superhydrophilic coating with a facile way.

Application of optimization algorithms in the development of a real-time coordination system for overcurrent relays

In this ongoing effort, optimization methods are being used to create a coordinated system for overcurrent relays that operates in realtime. There are several potential methods for coordinating the overcurrent relays, but each has its own set of performance benefits that the others lack. This effort entails the development and evaluation of three separate algorithmic strategies in order to accomplish this goal. After using the GA (Genetic Algorithm) as a baseline for performance, the DE (Differential evolution) & ACO (Ant Colony Optimization) are programmed and equated to it. DE and ACO were preferred because their excellent performance were recorded across various types of literature, and since no one in the security industry had ever attempted to implement them. This resulted in their being deemed the most suitable adoptees. As the number of coordination pairs increased, GA produced the worst results, was the slowest and had the greatest influence on execution time. This was learned by examining the discrepancies between the three algorithms’ outputs. Both ACO and DE, in contrast to GA, are much faster, provide better results, and are virtually immune to a rise in the number of coordination pairs.

Construction of new multi-cage-based MOFs using flexible triangular ligands for efficient gas adsorption and separation

Designing efficient absorbents for multi-gas adsorption and separation is of critical significance for gas purification in chemical engineering. Multi-cage structure enables sufficient interactions with multi-gas through the restriction effects, which is promising to achieve high multi-gas separation performance. In this work, two isomorphic metal-organic frameworks (MOFs) (SNNU-275, M ​= ​Cu, and SNNU-276, M ​= ​Ni) with three types of cages (octahedral M6L4, cuboctahedral M12L8, and M12L24), which are (3,4)-linked three-dimensional microporous structures formed by stacking M6(TPA)4 octahedral coordination molecular cages are synthesized by using tri(4-pyridyl) amine (TPA) ligands and Cu/Ni metals. TPA is selected as the central ligand due to the small size and flexible characteristics. The synthesized SNNU-275 exhibits a good combination of high C2H2/CO2 adsorption selectivity (28), while high C2H2 uptake capacity (68 ​cm3 ​g−1) is achieved for SNNU-276 with high stability. In addition, SNNU-275 and SNNU-276 exhibited superior uptake capacity for benzene and water vapor. Overall, this work not only provides new triangular tripyridine-based MOFs with multiple cages for efficient gas purification, but also demonstrated that the multicage engineering is a promising strategy for the multicomponent gas separation.

A Bioinspired Capillary Force‐Induced Driving Strategy for Constructing Ultra‐Low‐Pressure Separation Membranes

AbstractThe development of low‐pressure or pressureless self‐driven membranes is important for saving energy and overcoming the critical trade‐off effect in membrane separation processes. However, conventional self‐driven membranes rely on gravity, which is effective in the separation of large‐sized materials but is still ineffective in the fine separation of small molecules. Herein, inspired by the capillary effect that exists in nature, a capillary force‐induced membrane‐driving strategy for fine separation at ultra‐low pressures is demonstrated. Hydrophilic nanoparticles are prepared by a cross‐linking reaction between tannic acid and 3‐aminopropyltriethoxysilane and then introduce them into membrane pores to simulate sand accumulation with an aim to generate the capillary force. The membrane is then used in ultra‐low pressure membrane separation. Interestingly, it is found that the membrane has excellent performance in the separation of dye/salt mixtures (dye rejection > 99%, salt rejection < 10%) and a high permeate flux (160 L m−2 h−1) under near “zero pressure” conditions. Moreover, the structural stability of the membrane is verified. Introducing capillary forces into membranes as an autonomous driving force can be a promising universal approach that can be added up to the toolbox for the efficient preparation of separation membranes.

Efficient strategies for preparative separation of iridoid glycosides and flavonoid glycosides from Hedyotis diffusa.

Efficient strategies for the preparative separation of iridoid glycosides and flavonoid glycosides from Hedyotis diffusa using preparative high-performance liquid chromatography combined with appropriate pretreatment technologies were developed. Four fractions (Fr.1-1, Fr.1-2, Fr.1-3, and Fr.2-1) were firstly isolated from the crude extract of Hedyotis diffusa by column chromatography with C18, resin, and silica gel materials, respectively. Then, corresponding separation strategies were developed according to the polarity and chemical constituents. High-polar compounds of Fr.1-1 were purified by hydrophilic reversed-phase liquid chromatography and hydrophilic interaction liquid chromatography mode. The combination of C18 and phenyl columns realized the complementary separation of iridoid glycosides in Fr.1-2. Meanwhile, the improved selectivity caused by the change of organic solvent in the mobile phase was utilized to realize the purification of flavonoid glycosides in Fr.1-3 and Fr. 2-1. Finally, 27 compounds (purity>95%) mainly involving nine iridoid glycosides and five flavonoid glycosides were obtained. A complete strategy was established for the separation of a complex sample with a wide polarity range, to jointly solve the problems of enrichment of target components and separation of structural analogs.

LCST-mediated phase separation strategy for preparation of poly(amino alcohol ethers) microparticle-gelatin hydrogel composites

In this study, we report a facile two-step strategy to aid the preparation of microparticle-hydrogel composites. By leveraging amine-epoxy “click” chemistry, in combination with lower critical solution temperature (LCST)-mediated phase separation phenomenon of the in situ formed poly(amino alcohol ethers) (TP) prepolymer in water, as well as integration of gelatin, a series of poly(amino alcohol ethers) microparticle-gelatin hydrogel (TGP) composites can be readily prepared through the simultaneous preparation of bulk hydrogel network and microparticles. Our strategy allows easy tuning of microstructures and mechanics, as well as degradation properties of the obtained TGP composites through varying the volume ratio of TP prepolymer solution and gelatin solution. Moreover, applicability of such TGP composites to modulate cell response was demonstrated in vitro with NIH3T3 fibroblasts and chicken primary neurons. Furthermore, with hydrophobic domains in microparticles, such TGP composites are also feasible to tailor anti-inflammatory effect via curcumin encapsulation. Altogether, this study provides new insights into the design strategy to achieve microparticle-hydrogel composites to warrant consideration for drug delivery and tissue engineering applications.

Stepwise Separation for Calcium Recovery from an Ammonium Sulfate Leaching System

Calcium recovery from high calcium solid waste is driven by the latter’s growing environmental impact, emphasizing the need to develop a high value-added utilization approach. Inspired by our previous study, we develop a stepwise separation strategy for calcium recovery from an ammonium sulfate leaching system to efficiently remove iron and unburned carbon residue. In this study, tributyl phosphate (TBP) used as the carbon residue adsorbent for calcium recovery exhibits high selectivity and good recycling stability. Adsorption measurements show that TBP yields a superior carbon residue adsorption ability with a maximum adsorption ratio greater than 95%. Moreover, the adsorption percentage is also kept more than 90% after 10 cycles, which substantiates the good potential of TBP for reuse. Besides, the low concentration (1 mol/L) of H2SO4 provides an acidic environment, which makes TBP more feasible to be applied in carbon residue adsorption and effective iron(III) stripping. Furthermore, it is inferred from the Fourier transform infrared spectroscopy/X-ray photoelectron spectrometer and density functional theory analyses that the enhanced carbon separation performance may be ascribed to the carboxyl in carbon residue coordinated to the donor oxygen atom of TBP at the position of P–O. This work provides the foothold for further research on the recovery of calcium from industrial by-products.

A label-free multicolor colorimetric and fluorescence dual mode biosensing of HIV-1 DNA based on the bifunctional NiFe2O4@UiO-66 nanozyme

Finding the DNA of the human immune deficiency virus (HIV) with simple and sensitive detection is the main challenge in early diagnosis of AIDS. Herein, two-point separation strategies based on the colorimetric and fluorescence are introduced. The naked-eye qualitative and semiquantitative colorimetric, and also accuracy fluorescence quantification of HIV-1 DNA were applied using label-free NiFe2O4@UiO-66 nanozyme with both functions of peroxidase-mimetic like and emitting fluorescence. The DNA probe-conjugated nanozyme is employed to hybridize a sequence of HIV-1. NiFe2O4@UiO-66 nanozymes catalyze the decomposition of H2O2 to •OH which can produce a remarkable fluorescent product 2-hydroxyterephthalic acid (TAOH) by the oxidation of the bridging ligand of weakly fluorescent terephthalic acid (TA). The accessibility of H2O2 toward confined-NiFe2O4 MNPs was reduced by increasing the HIV-1 target DNA concentration, resulting in the fluorescence intensity of TAOH being decreased. Meanwhile, remaining the unreacted H2O2 was transferred an acidic colorimetric solution containing FeSO4 and gold nanorods (AuNRs). Increasing the amount of H2O2 available for longitudinal etching of AuNRs due to •OH-generating Fe+2-catalyzed H2O2 is reponsible for different colors from brownish to colorless depending on the HIV-1 target DNA concentration. The fluorescence intensity and obtained colors have offered the sensitive biosensing methods with a linear range from 0.05 to 300 and 1–200 pM, respectively with a detection limit as low as 1 fM. Our study revealed that the applied sensing assay provides a cost-effective and straightforward qualitative, semiquantitative, and sensitive quantitation visible monitoring without the necessity of high-end instruments for HIV-1 detection in a human blood plasma/serum samples.

Liquid Chromatographic Separation of MM 302 Da Polycyclic Aromatic Hydrocarbons in Synthetic Mixtures Using Chiral Stationary Phase Material

High molecular weight polycyclic aromatic hydrocarbons (HMW-PAHs) are an example of a family of compounds that exist with isomeric mixtures. While multi-instrument techniques may isolate many isomeric PAHs at qualitative and quantitative levels, complete separation of this class of environmental pollutant has not yet been attained, leaving ample room for method improvement. In this research, the separation of 21 commercially available isomers of MM 302 Da was studied using polysaccharide-based chiral immobilized materials as stationary phase. Isocratic, normal phase runs were performed using mixed concentrations and combinations of 302 Da PAH isomers. Retention times and calibration data were determined using a chiral chromatographic setup. Selectivity values are given for all the evaluated HMW-PAH isomers, retention and intensity factors were also calculated based on the directions outlined in Environmental Protection Agency Method 550.1, along with chromatographic peak resolution values. With the use of chiral separation, a total of 16 HMW-PAH peaks are visible on the chromatogram of the 21 MM 302 Da PAH synthetic mixture. This group of molecules does not possess chiral centers in the classical sense; however, larger molecules such as these may possess pseudochiral characteristics, providing a little-researched opportunity for separation strategy of formerly considered achiral molecules to be separated using chiral stationary phases. The resolution of this method makes it suitable for the identification and quantitation of MM 302 Da PAH isomers fractionated from a larger complex sample. The potential for this approach with other classes of high molecular weight achiral molecules is yet to be explored.

Identification of proteoforms by top-down proteomics using two-dimensional low/low pH reversed-phase liquid chromatography-mass spectrometry.

In top-down (TD) proteomics, efficient proteoform separation is crucial to reduce the sample complexity and increase the depth of the analysis. Here, we developed a two-dimensional low pH/low pH reversed-phase liquid chromatography separation scheme for TD proteomics. The first dimension for offline fractionation was performed using a polymeric reversed-phase (PLRP-S) column with trifluoroacetic acid as ion-pairing reagent. The second dimension, a C4 nanocolumn with formic acid as ion-pairing reagent, was coupled online with a high-field asymmetric ion mobility spectrometry (FAIMS) Orbitrap Tribrid mass spectrometer. For both dimensions several parameters were optimized, such as the adaption of the LC gradients in the second dimension according to the elution time (i.e., fraction number) in the first dimension. Avoidance of elevated temperatures and prolonged exposure to acidic conditions minimized cleavage of acid labile aspartate-proline peptide bonds. Furthermore, a concatenation strategy was developed to reduce the total measurement time. We compared our low/low pH with a previously published high pH (C4, ammonium formate)/low pH strategy and found that both separation strategies led to complementary proteoform identifications, mainly below 20kDa, with a higher number of proteoforms identified by the low/low pH separation. With the optimized separation scheme, more than 4900 proteoforms from 1250 protein groups were identified in Caco-2 cells.

A Novel Strategy for Liposomal Drug Separation in Plasma by TiO2 Microspheres and Application in Pharmacokinetics.

Liposomes are nano-scale materials with a biofilm-like structure. They have excellent biocompatibility and are increasingly useful in drug delivery systems. However, the in vivo fate of liposomal drugs is still unclear because existing bioanalytical methods for quantitation of total and liposomal-encapsulated drugs have limits. A novel strategy for liposomal-encapsulated drug separation from plasma was developed via the specific coordinate binding interaction of TiO2 microspheres with the phosphate groups of liposomes. Liposomal-encapsulated docetaxel was separated from plasma by TiO2 microspheres and analyzed by the UPLC-MS/MS method. The amount of TiO2, pH of the dilutions, plasma dilution factors and incubation time were optimized to improve extraction recovery. The characterization of the adsorption of liposome-encapsulated drugs by TiO2 microspheres was observed by electron microscopy. For understanding the mechanism, pseudo-first and the pseudo-second order equations were proposed for the adsorption process. The study fully validated the method for quantitation of liposomal-encapsulated in plasma and the method was applied to the pharmacokinetic study of docetaxel liposomes. The encapsulated docetaxel had a concentration range of 15-4000 ng/mL from the plasma sample using a TiO2 extraction method. Successful method validation proved the method was sensitive, selective and stable, and was suitable for quantitation of docetaxel liposomes in plasma samples. Extraction recovery of this method was higher than that of SPE method. As shown in electron microscopy, the liposomes adsorbed on TiO2 microspheres were intact and there was no drug leakage. The study proposed pseudo-first and the pseudo-second order equations to facilitate the adsorption of liposomal drugs with TiO2 microspheres. The proposed strategy supports the pharmacokinetic study of docetaxel liposomes in rats. TiO2 extraction method was stable, reproducible, and reliable for quantitation of encapsulated docetaxel. Because of versatility of lipids, it is expected to a universal bioanalysis method for the pharmacokinetic study of liposomes.

Isolation and quantification of a 17-epi-dammarane triterpenoid rhuslactone from roots of Rhus chinensis and its preventive effects on coronary heart disease and thrombosis in zebrafish

Based on mass spectrometry(MS)-guided separation strategy, compound 1 was obtained from the roots of Rhus chinensis. By comprehensive analysis of high resolution-electrospray ionization-mass spectrometry(HR-ESI-MS), nuclear magnetic resonance(NMR) data, and quantum chemical calculation of NMR(qcc-NMR) parameters, compound 1 was elucidated as rhuslactone, a 17-epi-dammarane triterpenoid with a rare 17α-side chain. An HPLC-ELSD method for its quantification in R. chinensis was established and adopted for the quantification of rhuslactone in different batches of R. chinensis. Rhuslactone displayed a good linear relationship within the range of 0.021 3-1.07 μmol·mL~(-1 )(r=0.997 6), and the average recovery was 99.34% [relative standard deviation(RSD) 2.9%). Moreover, the results of the evaluation test of the preventive effects of rhusalctone on coronary heart disease(CHD) and thrombosis showed that rhuslactone(0.11 nmol·mL~(-1)) significantly alleviated heart enlargement and venous congestion and increased cardiac output(CO), blood flow velocity(BFV), and heart rate, thereby reducing thrombus formation in zebrafish with CHD. The effects of rhuslactone on CO and BFV were superior to that of digoxin(1.02 nmol·mL~(-1)), and its effect on improving heart rate was comparable to that of digoxin. This study provides experimental references for the isolation, identification, quality control, and application of rhuslactone from R. chinensis against CHD. It is worth mentioning that this study has discussed some omissions in the determination of the stereochemistry of C-17 in dammarane triterpenoids in the present coursebook Chemistry of Chinese Medicine and some research papers, that is, the compound may be 17-epi-dammarane triterpenoid. This paper has also proposed steps for the establishment of C-17 stereochemistry.

A Microphase Separation Strategy for the Infrared Transparency‐Thermomechanical Property Conundrum in Sulfur‐Rich Copolymers (Advanced Optical Materials 5/2023)

In article number 2202432, Kyung Jin Lee, Jeong Jae Wie, Dong-Gyun Kim, and co-workers present an in-situ microphase separation strategy for the inverse vulcanization of elemental sulfur by utilizing self-crosslinkable 1,3,5-trivinylbenzene (TVB). Based on the microphase-separated architecture, poly(S-r-TVB)s exhibit robust thermomechanical properties, while still maintaining excellent infrared (IR) optical properties; such characteristics hold great promise for IR optical applications.

Distribution System State Estimation Using PV Separation Strategy in LV Feeders With High Levels of Unmonitored PV Generation

Distribution system state estimation (DSSE) is a critical analysis tool for active distribution networks (DNs). Unlike weighted least squares techniques, which are static DSSE methods, the augmented complex Kalman filter (ACKF) is a novel technique that considers the system’s dynamic behavior. Currently, most DNs integrate a large number of unmonitored residential photovoltaic (PV) generations. Existing unmeasured PV sources violate the white noise assumption in Kalman and least-squares-based estimators, causing the estimator to be biased. Because the one-step difference of aggregated customer demand is characterized as white noise, the suggested PV estimation technique based on the differencing strategy is used to decouple PV from the measured load. Using the specified contribution factors, the new online pseudo current injections are generated. In addition, the estimator’s accuracy is improved by using a new PV-scaling-aided ACKF approach based on the PV separation strategy. For validation purposes, this method is applied to real DN case studies. This study also makes use of an actual dataset to illustrate the efficacy of the proposed technique. The proposed technique outperforms the existing snapshot and dynamic DSSE techniques, and significant improvements are achieved in terms of accuracy and computational cost.

Nash equilibrium in emerging partnership-based Islamic banking industry with a Bayesian game-theoretic approach

PurposeA hypothesis developed in this paper models the relationship between the borrower and the bank as a dynamic game based on incomplete information (business game) and seeks an equilibrium point at which the facilitated applicant can act according to the terms of the loan agreement once the contract is signed and meet the requirements of the contract.Design/methodology/approachThe primary assumption in the formation of the Islamic bank in Islamic society is that the members of the society are Muslims and act according to religious orders. However, the non-fulfillment of divine principles and orders is always possible. In partnership agreements, the risk of infringement is reduced and corrupt contracts are prevented in some circumstances. Our basic model was constructed using the Beer-Quiche classic game, which has been modified dynamically along with a generalization of complexity terms. The information asymmetry led us to use a heterogeneous belief system to evaluate the probability of the customer transmitting a low credit risk signal to the bank and the probability of the customer transmitting a high credit risk signal to the bank. There are several assumptions of the basic model that are released in the extended model by the presence of a social inspector, by exploring credit risk signals in the generalized model and by considering various commitment levels in the comprehensive model.FindingsAs a result, it is observed that there is no Nash equilibrium in cases where the customer applies separation strategies. But if the pulling strategies are applied, the Nash equilibrium can be achieved under certain conditions, including inspection bodies in the banking system, the creation of necessary transparency and the proper treatment of criminals by government and regulatory bodies. So, by using alternative belief systems, applying different filters and paying attention to all sectors of the economy, new Nash equilibrium points can be achieved. Moreover, multi-stage facilities payment reduces the risk of corrupt contracts.Originality/valueThis paper sets out to analyze Nash Equilibrium and its possible encounter in Islamic Banking for the first time, utilizing a Bayesian Game-Theoretic framework. A major aspect of the research is the contribution to a better understanding of the role of transparency and government oversight in the implementation of Islamic banking regulatory standards.

Analytical Purity Determinations of Universal Food-Spice Curcuma longa through a QbD Validated HPLC Approach with Critical Parametric Predictors and Operable-Design’s Monte Carlo Simulations: Analysis of Extracts, Forced-Degradants, and Capsules and Tablets-Based Pharmaceutical Dosage Forms

Applications of analytical quality by design (QbD) approach for developing HPLC (High Performance Liquid Chromatography) methods for food components assays, and separations of complex natural product mixtures, are still limited. The current study developed and validated, for the first time, a stability-indicating HPLC method for simultaneous determinations of curcuminoids in Curcuma longa extracts, tablets, capsules, and curcuminoids' forced degradants under different experimental conditions. Towards separation strategy, critical method parameters (CMPs) were defined as the mobile phase solvents' percent-ratio, the pH of the mobile phase, and the stationary-phase column temperature, while the peaks resolution, retention time, and the number of theoretical plates were recognized as the critical method attributes (CMAs). Factorial experimental designs were used for method development, validation, and robustness evaluation of the procedure. The Monte Carlo simulation evaluated the developing method's operability, and that ensured the concurrent detections of curcuminoids in natural extracts, commercial-grade pharmaceutical dosage-forms, and the forced degradants of the curcuminoids in a single mixture. The optimum separations were accomplished using the mobile phase, consisting of an acetonitrile-phosphate buffer (54:46 v/v, 0.1 mM) with 1.0 mL/min flow rate, 33 °C column temperature, and 385 nm wavelength for UV (Ultra Violet) spectral detections. The method is specific, linear (R2 ≥ 0.999), precise (% RSD < 1.67%), and accurate (% recovery 98.76-99.89%), with LOD (Limit of Detection) and LOQ (Limit of Quantitation) at 0.024 and 0.075 µg/mL for the curcumin, 0.0105 µg/mL and 0.319 µg/mL for demethoxycurcumin, and 0.335 µg/mL and 1.015 µg/mL for the bisdemethoxycurcumin, respectively. The method is compatible, robust, precise, reproducible, and accurately quantifies the composition of the analyte mixture. It exemplifies the use of the QbD approach in acquiring design details for developing an improved analytical detection and quantification method.

A Single Source Self-Balanced Boost MLI with Reduced Part Count for EV Applications

As the use of inductor-based topologies demands a large amount of space, capacitor-based topologies have garnered attention. Electric Vehicles (EVs) are usually equipped with two-level inverters, which require separate control strategies for each level and synchronizing the strategies increases the complexity of operation and makes them unreliable. Therefore, a single-stage converter with boost and conversion abilities with better power quality at optimal component count and efficiency is needed. A novel capacitor-based boost multilevel inverter (CB-MLI) topology is proposed in this paper as it is found suitable for EV and HEV applications. It is capable of generating an eleven-level waveform with only eleven switches, three capacitors, and a single isolated source. The self-balancing property of the capacitors makes the topology one of a kind. A constant carrier PWM-based control strategy is utilized to switch the IGBTs. Testing results from hardware setup confirm the proposed capacitor-based CB-MLI topology operating modes and potentiality. Lastly, by highlighting the proposed and existing MLI circuits, the benefits of the recommended configuration are outlined by component count and total cost. Additionally, it is a simplified design that needs fewer footprint areas and space.