Pretreatment Step Research Articles

SAS-HRM: Secure Authentication System for Human Resource Management

To guarantee data confidentiality and information sensitivity, human resource management requires secure systems. In the field of authorization and dependability in recognizing and identifying persons, facial recognition has grown in importance. In this research, a secure authentication system is proposed based on biometric aspects of the user's face and identifying it using the CNN classification model is provided to give access to human resource management and update data. The system is divided into four major stages: First, set up the system environment, beginning with smart cards, card readers, Arduino, and so on. Second, after undergoing pre-treatment steps, the facial characteristics are extracted using LDA. Third, create a high-accuracy CNN model to recognize and classify the user's face among the system's users. Finally, the user is allowed to enter the system and update his information. When compared to the accuracy of classification using machine learning techniques with a CNN proposed model, the accuracy of the model with LDA was up to 100%. K-NN has 91%, while TD has 94%.

Comparative study of lignin and sodium lignosulfonate extracted from irradiated and non-irradiated sawdust wastes

Recent technologies in the production of chemicals and bio-material products are focusing on lignocellulosic biomass resources since it is the world's most abundant economical material, recyclable, sustainable, low cost, as well as highly renewable natural resources. This biomass refers to agricultural wastes such as woody plants (soft and hardwood). Lignin is extracted from these agro-wastes using chemical methods and ionizing radiation. The outcome of employing gamma radiation as a pretreatment step prior chemical treatment on the duration for alkaline, acid, and production of sodium lignosulfonate (NaLS) was examined. The structure of the produced NaLS was verified utilizing Nuclear magnetic resonance (1H-NMR, 13C-NMR) and Liquid chromatography–mass spectrometry (LC–MS). A comparison between the physicochemical properties of sodium lignosulfonate extracted from both non-irradiated and irradiated sawdust waste was studied using FTIR, XRD, EDX and TGA. The degree of sulfonation of the produced NaLS was determined utilizing the potentiometric titration method. The findings demonstrated that gamma exposure pretreatment step reduces the time of alkaline, acid, and sulfonation processes as well as a higher yield percentage and degree of sulfonation.

The pretreatment method in marine organisms and sediment for microplastics analysis by FTIR using “Cylindrical microplastics fractionator”

For the detection of microplastics (MPs) in aquatic biota using Fourier transform infrared spectroscopy (FTIR), the ability to remove organic matter (OM) in pretreatment steps is essential to increase the time efficiency of MPs measurement and method uniformity. In principle, decreasing OM can be achieved by increasing the number of pretreatment steps. However, MPs are lost in proportion to the number of transfers between each step. Therefore, we have created a "Cylindrical MPs Fractionator" composed of commercially available materials. This container allows for a six-step pretreatment process that is designed to increase the removal capacity of OM with only one transfer to prevent the loss of MPs.•Biological or sediment samples are placed in the extractor and subjected to chemical treatment and density separation.•Residues containing MPs are obtained on filters by vacuum filtration.•After additional chemical treatment of the obtained residue, the components of the residue are identified by microscopic FTIR.This method removed 99.3% of OM and recovered 88.5% of MPs. The presenting method confirmed that this can be used with the same process for 11 organisms and sediments from estuarine ecosystem in Japan as models.

Improving anti-fouling properties of alumina tubular microfiltration membranes through the use of hydrophilic silica nanoparticles for oil/water separation

ABSTRACT In this study, hydrophilic silica nanoparticles (Si NPs) were used to modify α-alumina tubular membranes to improve their performance in terms of flux, oil rejection, and anti-fouling properties. Our work focuses on enhancing membrane performance, particularly for difficult applications such as produced water treatment. The prepared membranes were applied for oil-in-water emulsion treatment. After coating hydrophilic Si NPs, the oil contact angle improved from 133.8° to 171.4°. To prevent Si NPs from leaching off the surface of α-alumina tubular membranes, polyvinyl alcohol was used to coat the membranes as a pre-treatment step before Si NP modification. After coating the membrane with Si NPs, the roughness of the membrane surface decreased, likely leading to less fouling. After coating Si NPs, Total Organic Carbon rejection increased from 93.1% for pristine α-alumina tubular membranes to 97.7% for silica-modified membranes because of hydrophilic improvements of the modified membranes. The Si NP coating improved the anti-fouling property of membranes with the flux recovery ratio increasing from 71.3% for pristine α-alumina tubular membranes to 85.9% for silica-modified membranes. Scanning Electron Microscopy, Energy-dispersive X-ray spectroscopy, oil contact angle, and Atomic Force Microscopy characterization tests were done. The tests showed successful Si NPs impregnation and altered wettability.

High-Performance Cannabinoid Sensor Empowered by Plant Hormone Receptors and Antifouling Magnetic Nanorods.

The misuse of cannabinoids and their synthetic variants poses significant threats to public health, necessitating the development of advanced techniques for detection of these compounds in biological or environmental samples. Existing methods face challenges like lengthy sample pretreatment and laborious antifouling steps. Herein, we present a novel sensing platform using magnetic nanorods coated with zwitterionic polymers for the simple, rapid, and sensitive detection of cannabinoids in biofluids. Our technique utilizes the engineered derivatives of the plant hormone receptor Pyrabactin Resistance 1 (PYR1) as drug recognition elements and employs the chemical-induced dimerization (CID) mechanism for signal development. Additionally, the magnetic nanorods facilitate efficient target capture and reduce the assay duration. Moreover, the zwitterionic polymer coating exhibits excellent antifouling capability, preserving excellent sensor performance in complex biofluids. Our sensors detect cannabinoids in undiluted biofluids like serum, saliva, and urine with a low limit of detection (0.002 pM in saliva and few pM in urine and serum) and dynamic ranges spanning up to 9 orders of magnitude. Moreover, the PYR1 derivatives demonstrate high specificity even in the presence of multiple interfering compounds. This work opens new opportunities for sensor development, showcasing the excellent performance of antifouling magnetic nanorods that can be compatible with different recognition units, including receptors and antibodies, for detecting a variety of targets.

Redox Cycling Amplified Electrochemical Lateral-Flow Immunoassay: Toward Decentralized Sensitive Insulin Detection.

While paper-based lateral-flow immunoassays (LFA) offer considerable promise for centralized diagnostic applications, the analytical capability of conventional LFA remains constrained due to the low sensitivity of its common optical detection strategy. To address these issues, we report a simple electrochemical LFA (eLFA) with nanocatalytic redox cycling for decentralized insulin detection. Simultaneous binding of insulin with detection antibodies and capture antibodies through the capillary flow at the LFA platform and signal amplification through the rapid nanocatalytic reduction of [Fe(CN)6]3- (Fe3+) with Au nanoparticles (AuNP) and ammonia-borane (AB), coupled to electrochemical redox cycling reactions involving Fe3+, AuNP, and AB on the carbon working electrode, offer higher sensitivity than conventional colorimetric LFA and enzymatic redox cycling. The resulting integrated eLFA strip allows the detection of low insulin concentrations (LOD = 12 pM) and offers considerable promise for highly sensitive decentralized assays of different biological fluids (saliva and serum) without additional pretreatment or washing steps.

A dual-functional single-atom Fe nanozyme-based sensitive colorimetric sensor for tannins quantification in brandy

Traditional methods of tannins detection suffer from complex pretreatment, long detection time, and limited sensitivity. Modern techniques like liquid chromatography require expertise, involve tedious result processing, and lack effective data visualization. Therefore, there is a need for an alternative detection method that simplifies pretreatment and detection steps, reduces analysis time, and provides visualized results. In this study, a novel colorimetric sensor based on single-atom Fe nanozyme (Fe@CN-20) was developed for tannins detection. Fe@CN-20 exhibited laccase-like and oxidase-like activities, enabling simultaneous oxidation of tannins and a substrate called TMB. Tannins competed with TMB, allowing quantification of tannins content. The Fe@CN-20/TMB system provided a detection range of 5–100 mg/L tannic acid, with a detection limit of 0.13 mg/L (S/N = 3). Analysis time was approximately 30 min. The platform successfully quantified tannins in brandy, showing less than 5% deviation compared to the standard method. The sensor was simple, sensitive, rapid, and provided strong visualization.

Response of Bacillus subtilis to Salt and Acid Stresses and the Optimal Effect on Fermentation of Locust Bean (Parkia biglobosa) Seeds into Iru (A Soup Condiment)

This study aimed at evaluating the performance of Bacillus subtilis stressed in varying single-factor salt and acid concentrations as pre-treatments in the fermentation of African locust bean seeds (Parkia biglobosa) into iru, a commonly consumed soup condiment. Microorganisms were isolated from commercial iru and the result showed that there was a predominant bacteria growth, with a mild mold growth. The bacteria isolated were species of Bacillus, Micrococcus and Pseudomonas. Biochemical tests were carried out on the Bacilus species; and Bacillus subtilis was isolated and identified. The isolated B. subtilis was cultured under different acid (pH 3.5, 4.5 and 5.5) and salt (1%, 2.5% and 5% NaCl) concentrations. Notable growths were seen at all salt concentrations but no growth was observed at very high acid concentrations (pH 3.5 and 4.5). Isolates from varying cultural conditions were used as single starters to ferment the locust bean seeds into iru (at 37 oC for 72 h), with subsequent evaluation of their performance in the fermentation process and final product. The results revealed that stressing the organism as a pretreatment step had a positive significant effect on the nutritional, antinutritional, physicochemical, and sensory properties of the fermented iru. This study therefore concludes that the introduction of appropriate starter culture such as B. subtilis with appropriate modifications could contribute to improved preservation, quality and safety of traditionally fermented foods. The overall acceptability of the samples fermented with the stressed B. subtilis compared favourably with the control samples.

Development of organic three-phase laminar flow microfluidic chip for extraction of ginsenosides from Panax ginseng

BackgroundHerbal extracts contain multiple active constituents, so the sample preparation based on the liquid-liquid extraction (LLE) is demanding, especially when a study subsequent to extraction is needed. Since the laminar flow occurring in microchannels can be formed between two miscible organic phases, a new method of extracting polar compounds from the crude extract of Panax ginseng Meyer in aqueous ethanol by pure n-butanol in the three-phase laminar flow microfluidic chip was established. MethodsA new chip consisting of long microchannels with a guide structure was employed to improve the extraction efficiency caused by the low diffusion ability of saponins. The method was evaluated by using the extraction yields and purities of ginsenosides Rg1, Re and Rb1 as the indicators, and extraction conditions such as flow rate, temperature and other governing factors were optimized. ResultsUsing the new chip method, the extraction efficiencies of ginsenoside Rg1, Re and Rb1 were 63.1%, 69.5% and 71.6%, respectively, which are higher than the 26% achieved in a previous report. The extraction yields of 1.53, 0.51, 0.90 mg/g were also higher than those obtained previously by the successive laminar flow microchip method. ConclusionThe proposed new microfluidic chip method has simplified the sample pretreatment steps to improve the yield of ginsenoside extraction from ginseng samples.

Role of some structural features in EPS from microalgae stimulating collagen production by human dermal fibroblasts

ABSTRACTExopolysaccharides (EPS) from the microalgae Porphyridium cruentum, Chrysotila dentata, Pavlova sp., Diacronema sp., Glossomastix sp., Phaeodactylum tricornutum, and Synechococcus sp. were isolated and depolymerized. First, EPS were submitted to a high pressure pre-treatment step, followed by a solid acid-catalyzed hydrolysis step carried out in a batch or recycle fixed-bed reactor, using a strong acidic cation-exchange resin. Twenty-eight different EPS forms were thus obtained. After characterization of their main structural features (weight- and number-averaged molecular weight, polydispersity index, sulfate and uronic acid contents), we investigated the structure–function relationship of their pro-collagen activity. We found that native microalgae EPS were able to inhibit until 27% of human matrix metalloproteinase-1 (MMP-1) activity while the depolymerized forms were able to enhance collagen production by two different human fibroblast lines, used as cell models due to their major role in dermal collagen biosynthesis. The most active EPS forms, obtained by depolymerization in the recycle fixed-bed reactor of D. ennorea and Glossomastix sp. EPS, led to 390% increase in collagen production. Finally, principal component (PCA) and Pearson analyses indicated that MMP-1 inhibition was strongly correlated to the sulfate group content of EPS whereas collagen production by fibroblasts was mostly related to their proportion of low molecular weight polysaccharides (<10 kDa). Uronic acid content of EPS was also shown essential but only if the size of EPS was reduced in the first place. Altogether, these results gave new insights of the dermo-cosmetic potential of microalgae EPS as well as the key parameters of their activity.

Effects of irradiation on the insolubility of sodium fast reactor (U,Pu)O2 mixed oxide with a very high amount of plutonium

Sodium fast nuclear reactors might operate with MOX fuels containing up to 45% of plutonium, nevertheless, the reprocessability of spent nuclear fuel is sparsely investigated in the literature for plutonium contents higher than 30%. The dissolution step is a critical stage for MOX fuels since plutonium oxide exhibits a much slower dissolution kinetics as compared to uranium oxide. In particular, many authors suggested a significant change in the dissolution behavior of mixed oxides for plutonium contents between 30% and 50%. In this paper, the dissolution tests of unirradiated and irradiated CAPRA pellets with an initial plutonium content of 45% is described. Up to our knowledge, this is the first dissolution test reported in the literature with such high plutonium content in irradiated nuclear fuel. The fresh unirradiated pellets appears almost insoluble due to a very slow dissolution kinetics. Although the insolubility remains high after irradiation, a beneficial effect of irradiation on the dissolution behavior is observed with a depletion factor of five. The dissolution rates observed are very consistent with previous studies reported in the literature. The results show that complementary steps such as fuel pre-treatment or depletion steps should be considered in order to recycle spent nuclear fuel highly enriched in plutonium.

Feasibility study of utilization of palm oil mill effluent (POME) as a source for microalgae nutrients

As palm oil productivity increases, the waste produced will increase. Every palm oil industry produces liquid waste known as palm oil mill effluent (POME). POME contains very high BOD and COD so that it can inhibit microalgae growth. Therefore, comprehensive research is needed to find pre-treatment steps to reduce the COD and BOD content in POME before it is used as a medium for the growth and development of microalgae. The experimental mixture procedure carried out POME and microalgae according to the specified ratio. Research shows that Pond IV POME waste can be used as wild microalgae to grow, thereby reducing the BOD and COD levels of POME waste. Variable modifiers were applied to the volume of POME to the ratio of microalgae volume and the amount of nutrients provided. Microalgae growth with a ratio of 1:4 resulted in a decrease in BOD and COD to 61.66 ppm and 173.33 ppm from 110.6 ppm and 496.67 ppm. On the effect of providing C nutrition (120 ppm), resulted in lower BOD and COD at 65.33 ppm and 186.67 ppm, while the effect of providing N (40 ppm) nutrition resulted in lower BOD and reached 55.41 ppm and 158.33 ppm.

Electrocoagulation flotation as a municipal wastewater (pre-)treatment technology: Effect of weather conditions and current density

Electrocoagulation (EC) is a promising compact alternative technology, despite its viability in municipal wastewater treatment (MWWT) is currently challenged by its energy-intensive and batch-mode operation. This study introduces an innovative continuous electrocoagulation flotation (ECF) design for MWWT. ECF shows promising pollutant removal efficiencies, with identical results using both iron (Fe) and aluminum (Al) anodes. At a current density (CD) of 120 A/m2, it achieved significant removals: 90% tCOD, 98% TP, 94% TSS, 60% BOD5, and 40% TN. Designed ECF is proposed as a pre-treatment step due to limited TN removal. The study investigated optimal ECF performance under varying weather conditions using CD ranges of 40, 80, and 120 A/m2. Both Fe and Al ECF outperformed in treating rainy weather (RW) and dry weather (DW) municipal wastewater (MWW). However, Al anode's super-faradaic behavior resulted in higher residual concentrations in effluent, (i.e., an average of 6.53–33.7 mg/L), and operational costs compared to Fe ECF. Optimized Fe ECF setting needs to be changed depending in the weather variation. Fe ECF achieved high removal rates for tCOD (94%) and TP (95%) in RW MWW at a low CD of 40 A/m2. Comparative to this, the optimum CD for treated DW MWW was between 40 and 80 A/m2, removing tCOD (71–73%) and TP (85–95%). Specifically, at these conditions, the operational expenses were respectively 0.47 ± 0.03 €/m3 (RW MWW), and 0.37 ± 0.02 €/m3 to 0.81 ± 0.04 €/m3 (DW MWW). Moreover, ECF enables resource recovery and a circular economy through anaerobic sludge digestion, with Fe ECF generating more biogas than Al.

Progress in the application of novel nano-materials to the safety analysis of agricultural products

The quality and safety of agricultural products are strongly related to human livelihood. Thus, the government and consumers have recently paid increased attention to the quality and safety of agricultural products. The development of efficient, rapid, and sensitive analytical methods for detecting pesticides, veterinary drugs, heavy metals, mycotoxins, and environmental pollutants in agricultural products is of great significance. Owing to the complexity of many sample matrices and the low concentration of pollutants in a typical sample, appropriate sample pretreatment steps are necessary to enrich pollutants in agricultural products. Solid-phase extraction (SPE) is the most widely used sample pretreatment technology; in this technique, the adsorbent generally determines the selectivity and efficiency of the extraction process. An increasing number of novel materials have been used as SPE adsorbents. The extraction efficiency, extraction selectivity, and analytical throughput of SPE could be greatly improved by combining these novel materials with various extraction modes (e. g., solid-phase microextraction, dispersed SPE, and magnetic SPE (MSPE)) during sample preparation. Because of their large specific surface area and high affinity toward target analytes, nanomaterials are often used as SPE adsorbents, thereby greatly improving the selectivity and sensitivity of the analytical technology. More importantly, these materials have become a priority area of research on preconcentration technologies for trace compounds in agricultural products. This paper summarizes the adsorption characteristics of several new nanomaterials, including magnetic materials, carbon-based materials, metal nanomaterials (MNs), metal oxide nanomaterials (MONs), metal organic frameworks (MOFs), and covalent organic frameworks (COFs). These nanomaterials present numerous advantages, such as large specific surface areas, high adsorption capacities, and tailorable structural designs. MSPE employs magnetic materials as sorbents to afford fast dispersion and efficient recycling when applied to complex sample matrices under an external magnetic field. The use of MSPE can avoid several typical problems associated with SPE such as poor adsorbent packing and high pressure, thereby greatly simplifying the pretreatment process and providing a high flux for sample analysis. Carbon-based materials are powdered or bulk nonmetallic solid materials with carbon as the main component; carbon and nitrogen materials, mesoporous carbon, carbon nanotubes, and graphene are some examples of these materials. These materials provide large specific surface areas, abundant pore structures, good thermal stability, high mechanical strength and adsorption capacity, and controllable morphology. Pure and modified carbon nanomaterials have been successfully used to purify target analytes from agricultural products. Given their unique physical and chemical properties, MNs and MONs have attracted significant interest for use in sample preparation. MNs and MONs with excellent thermal and mechanical stabilities show good resistance to a wide pH range and diverse organic solvents, which is crucial in adsorbent-based extraction methods. The surface of these materials can be easily modified with various ligands to improve their selectivity. MOFs and COFs present many advantages such as large specific surface areas, high porosity, adjustable pore performance, and good thermal stability. Several methods that employ novel adsorbent materials to analyze pollutants in a variety of agricultural products, such as chromatography, spectroscopy, mass spectrometry, and other detection technologies, have been established. This paper also reviews the application of adsorbent materials in the analysis of agricultural product quality and safety, and discusses the future development trends of these sorbents in sample preparation for the safety analysis of agricultural products.

Adsorption of Hexavalent Chromium Ions Using Pine Sawdust Cellulose Fibres

In developing countries, agriculture generates not only income but also waste. Therefore, it is essential to recycle this waste for different purposes. This study explored an affordable way to modify pine sawdust to treat chromium-containing wastewater, with successful outcomes. The biosorbent’s surface area was enhanced through pretreatment steps, including NaOH treatment, bleaching, and acid hydrolysis for cellulose fibre extraction. SEM–EDS, TEM, and XRD were used to study the chemical composition and morphology. XRD measurements also revealed a rise in the sizes of crystallites. FTIR results revealed shifts in bands (-OH), (-C-H), and (-COOH), suggesting their involvement in Cr (VI) ion adsorption. TGA/DTA indicated enhanced thermal stability for cellulose extracted from pine sawdust compared to untreated pine sawdust. The adsorption parameters for Cr (VI) ions were investigated through mass, pH, stirring time, and temperature studies. The optimal Cr (VI) adsorption conditions were 2.0 g mass, pH 6, 90 min stirring, 100 mg/L concentration, and 313 K temperature. The adsorption of Cr (VI) ions was best-fit to the Langmuir isotherm model (R2 = 0.9991, kL = 0.09). Pseudo-second-order kinetics (R2 = 0.9999) provided the best description for Cr (VI) biosorption on cellulose fibres (CF). The analysis results confirmed the isotherm and kinetics models. The negative thermodynamic parameters (ΔG° and ΔH°) indicated that the uptake of Cr (VI) ions on the adsorbent was exothermic and spontaneous.

Turning waste into value: eco‐efficient recovery of by‐products from biomass pretreatment in lignocellulosic biorefineries

AbstractThis original research contributes to enhancing the viability of biorefineries through recovering valuable by‐products from the liquid remaining after the biomass pretreatment by hot liquid water. A novel downstream processing method is developed for the recovery of acetic acid, formic acid, furfural and 5‐hydroxymethylfurfural (HMF) by enhanced distillation. The major challenge in this research is the processing of the highly diluted initial solution (&gt;96 wt% water) and the thermodynamic limitations owing to possible formation of several azeotropes. This new process recovers 78.7% of the acetic acid (99.8 wt%), while the rest of it is recycled back to the biomass pretreatment step together with most of the separated water from the initial solution. Over 99.5% of formic acid, furfural and HMF is also recovered, at purities of 74.7, 98.0 and 100 wt%, respectively. Vapor recompression and heat integration are implemented to decrease the energy use. The results demonstrate a 77.4% decrease in total annual costs (from $3.44 to 0.78/kgproduct), a 75.0% reduction in minimum average selling price (from $3.50 to 0.87/kgproduct), an 81.1% reduction in energy requirements (from 77.41 to 14.66 kWthh/kgproduct) and an up to 99.7% decrease in CO2 emissions (from 11.17 to 0.03 kgCO2/kgproduct).

Enhanced Performance of Recovered Cathode Materials with Fluorine Impurity in Hydrometallurgy Recycling

With the growing lithium-ion battery (LIB) industry since its initial inception in the late 20th century, battery recycling is seen as an end-of-pipe process to resolve environmental and economic issues generated by the accumulation of waste batteries. In recent years, an increasing attention has been paid to the hydrometallurgy recycling due to its high recovery efficiency, low energy cost, as well as large-scale production capability. In order to achieve a high-quality recovered material, many resources have been poured into this field trying to develop better design and control of synthesis process. The impurities introduced in the recycling process is an important factor which could have unintended impacts on the final cathode product in a variety of aspects. The presence of fluoride ions in hydrometallurgy recycling, as one possible anion impurity which is released from the LiPF6 in electrolyte, aroused our research interest. In this work, the influence of the fluorine impurity on the recovered LiNi0.6Co0.2Mn0.2O2 (“NCM622”) cathode material via hydrometallurgy method is systematically investigated. The results show that the addition of fluorine impurity in the hydrometallurgy process improves the electrochemical properties of the recovered cathode materials.It is found that the fluorine impurity has lots of positive impacts on the synthesized cathode materials. First of all, the equilibrium of co-precipitation reaction is affected by the fluoride ions, resulting in the formation of holes in hydroxide precipitates. After sintering, cathode particles preserve a hollow structure which leads to an improved rate capability and cycle stability. In addition, surface oxygen sites of cathode materials are found to be substituted by impurity fluoride ions. As a result, an increased surface Ni2+ concentration contributes to a better cathode surface stability as well as a higher reversible capacity. The inclusion of fluoride (<1 at%) in cathode lattice is also beneficial to the bulk lithium-ion diffusion. Not only that, but the fluorine impurity has no clear detrimental effects on the particle morphology, crystal structure, transition metal composition, and element distribution of the cathode materials. Therefore, the electrochemical performance of synthesized cathodes has achieved different levels of improvement due to those positive influences from the fluorine impurity. Specifically, cathode with 0.2 at% impurity exhibits a discharge capacity of ~168 mAh/g with a remarkable retention of 98% at 1/3C after 100 cycles, about 8% higher than the capacity of virgin benchmark. Also, rate test outcomes of fluorine-affected samples are superior to that of virgin standard. In summary, the electrochemical properties of recovered cathode via hydrometallurgy process can be boosted by fluorine impurity. Unlike adverse impurities, fluoride’s positive role in hydro-recycling indicates that it is no need to strictly control them in pre-treatment steps. Figure 1

Nanocomposite based on green synthesis of gold nanoparticles decorated with functionalized multi-walled carbon nanotubes for the electrochemical determination of hydroxychloroquine

In this study, a selective and sensitive electrochemical approach for determining hydroxychloroquine (HCQ) was proposed. A novel nanocomposite based on gold nanoparticles synthesized by green synthesis in an extract of white pitaya (Hylocereus undatus) (AuNP-Ext) decorated with functionalized multi-walled carbon nanotubes (f-MWCNTs) was presented. AuNP-Ext was characterized by ultraviolet-visible spectroscopy and the f-MWCNTs/AuNP-Ext nanocomposite by transmission electron microscopy. The nanocomposite was used to modify a glassy carbon electrode (GCE). Using the f-MWCNT-AuNP-Ext/GCE sensor, an irreversible oxidation peak at +0.74 V vs. Ag/AgCl was verified by HCQ. The calibration plot was studied in two linear ranges, from 0.03 to 3.5 µmol/L and from 3.5 to 17.0 µmol/L, with a limit of detection of 0.0093 µmol/L and a limit of quantification of 0.031 µmol/L, regarding the first linear range. The proposed sensor was successfully applied to the determination of HCQ in pharmaceutical and clinical samples without any special purification, separation or pre-treatment steps. The accuracy was verified by UV-Vis spectrometry, and this revealed that the proposed method was accurate and precise, as evidenced by F- and t-tests.

Enzyme technology in bioethanol production from lignocellulosic biomass: Recent trends with a focus on immobilized enzymes

Enzyme immobilization is a useful tool to produce biocatalysts with improved performance, such as high activity, high stability at operational conditions, and easy recovery and reuse. In this context, the production of second-generation ethanol using immobilized enzymes was reviewed. Emphasis was placed on the pre-treatment and/or hydrolysis steps to increase efficiency and reduce the cost of the process. In addition, the process design of bioethanol using immobilized enzymes was critically reviewed. In the enzymatic pre-treatment, laccases, manganese peroxidases, lignin peroxidases, and lytic polysaccharide monooxygenases are the main enzymes involved. When considering processes with heterogeneous biocatalysts, laccases are the most explored enzyme. In the hydrolysis step, cellulases and hemicellulases or a mixture of them are the main enzymes explored in the literature frequently using magnetic nanoparticles as support for enzyme immobilization. Although enzyme immobilization is a mature technology, the use of these biocatalysts is frequently limited to only one step of the bioethanol production process, such as pre-treatment or hydrolysis performed using Benchmark Technology. However, some recent papers have explored innovative design processes using a mixture of immobilized enzymes or co-immobilized enzymes to join some process steps, thereby decreasing the cost of enzymes and equipment.

The CombE-IDMS Assay as an Alternate Potency Method for Adjuvanted Quadrivalent Influenza Vaccines.

The potency of all currently licensed inactivated influenza viral vaccines is assayed by the single radial immunodiffusion (SRID) method. SRID relies upon antisera and reference antigen reagents which are produced, standardized, and distributed in the mass quantities needed for vaccine manufacturers only after a significant amount of time has elapsed from the seasonal strain recommendations issued by the WHO; this time delay is exacerbated under conditions of an emerging pandemic. Previously, the limited trypsin digestion isotope dilution mass spectrometry (LTD-IDMS) method, which does not require antisera or reference antigens, demonstrated comparable quantitation of immunologically active hemagglutinin, the primary viral antigen, to SRID in stressed vaccine materials. Here, we demonstrate a streamlined improvement to the LTD-IDMS method by eliminating the need for its precipitation and washing steps, saving time and labor in the sample preparation process while paving the way for plate-based high-throughput analysis. This is accomplished using dissimilar proteases in the pretreatment (a combination of chymotrypsin and elastase) and analytical (trypsin) digestion steps so that any pretreatment digests will not cause interference while monitoring analytical tryptic digests by IDMS. The combination of enzymes (CombE)-IDMS method is tested alongside LTD-IDMS and SRID for the first time on MF59 adjuvanted seasonal cell-based quadrivalent influenza vaccines (aQIVc) under stressed conditions of heating, oxidation, lowered and elevated pH, and freeze-thaw. Overall, a correlation in the degradation trend is observed between CombE-IDMS and SRID in the four strains of the quadrivalent formulation, highlighting the method's stability indicating capability as a rapid alternate potency assay in a highly complex formulation of aQIVc.