Sample Concentration Research Articles

Alleviating symptoms of paediatric acute rhinosinusitis and acute otitis media with otorrhea using nasal-spraying Bacillus probiotics: a randomized controlled trial

Acute rhinosinusitis (ARS) in children may be accompanied by acute otitis media (AOM) which is often associated with bacterial co-infections. These conditions are among the primary reasons that children visit hospitals and require antibiotic treatment. This study evaluated the efficacy of the nasal-spraying probiotics (LiveSpo Navax containing 5 billion Bacillus subtilis and B. clausii spores/5 mL) as a supportive treatment for dual ARS and AOM with otorrhea in a randomized, single-blind, controlled clinical trial. Eighty-two patients (41 per group), aged 1 month to 12 years, received standard care along with nasal spraying of either physiological saline (Control group) or LiveSpo Navax (Navax group), administered three times daily over a 7-day follow-up period. A total of sixty-one patients (30–31 per group) completed the trial. The Navax group experienced 68.00% and 96.77% reductions in nasal congestion (by day 3) and rhinorrhea (by day 7), respectively, which were 2.04 and 1.94-fold higher than the Control group, with odds ratios (OR) of 4.31 and 30.00 (p < 0.05). Endoscopic results indicated 8% and 11% higher reductions in nasal mucopurulent discharge and tympanic membrane hyperemia in the Navax group compared to the Control group. By day 3, compared to day 0, the Navax group exhibited > 1200-fold reduction in Streptococcus pneumoniae and ≥ 4-fold reduction in Haemophilus influenzae concentrations (p < 0.05) in both nasopharyngeal and middle ear fluid samples, whereas the Control group showed no significant reductions. Navax treatment reduced IL-6 by 1.35- to 1.74-fold and TNF-α by 1.17- to 1.45-fold, more effectively than the Control group (p < 0.05). These results suggest that nasal-spray Bacillus spore probiotics, with their ability to reduce bacterial load and modulate immune responses, provide a cost-effective and safe solution for alleviating symptoms of both ARS and AOM in children.Trial registration: ClinicalTrials.gov, Identifier NCT05804123 on April 7, 2023.

Comparison of Radiation Levels in the Soil and Rocks in the Areas Surrounding Old Phosphate Mine, Russaifa, Jordan

Abstract The activity concentrations of the terrestrial naturally occurring radionuclides 214Pb, 214Bi (from 238U series), and 228Ac (from 232Th series) and 40K were measured in soil and rock samples obtained from three sites of the Russaifa mine and its surrounding in the Russaifa region using an HPGe-detector of 20 % relative efficiency. While the soil activity (in Bq/kg) was found to be: 408.63 ± 26, 383.9 ± 4.7, and 383.0 ± 4.0 for 238U, 214Bi, and 214Pb, respectively. The rock activity was found to be 225.4 ± 19, 180.36 ± 3.9, and 179.47 ± 3.1 for 238U, 214Bi, and 214Pb, respectively. Our results reveal that the average activity concentrations in the mine (site 1) are higher than worldwide average values [6] for 238U, 214Pb, and 214Bi. In contrast, the results show that the average absorbed dose rates in the other sites 2 and site 3 are lower than the world average for all radionuclides measured in this study. Also, the average activity concentrations in soil samples 238U, 214Pb, and 214Bi are higher than the average activity concentrations in rock samples in all sites. Furthermore, the average absorbed dose rate (in nGy h-1) was found to be 265.3 for 238U, 233.3 for 214Bi, and 13.3 for 214Pb, respectively, and the average absorbed dose rates for both 228Ac and 40K were below the minimum detectable activity (MDA). Moreover, the average annual effective dose rates in soil and rock samples were estimated. While it is found to be 366.90 µSv for 238U, 306.84 µSv for 214Bi, and 37.58 µSv for lead in soil samples, for the rock samples it is found to be 163.75 µSv for 238U, 105.83 µSv for 214Bi, 13.05 µSv for lead. However, the average annual effective dose rates for 214Bi and 40K in soil and rock samples are below the minimum detectable activity (MDA). The results display that the average outdoor annual effective doses for both 238U and 214Bi are higher than the world average and the average outdoor annual effective dose equivalents for the other radionuclides are lower than the world average. They also show that the average outdoor annual effective doses in soil samples for 238U, 214Pb, and 214Bi are higher than the average outdoor annual effective doses in rock samples.

Temporal Changes in Lead and Cadmium Levels in Amanita muscaria Samples Collected in Poland

In recent years, an increasing popularity of consuming Amanita muscaria has been observed in Poland, aimed at reducing various medical symptoms. However, there is a lack of data regarding the impact of variations in the content of toxic elements, such as cadmium (Cd) and lead (Pb), in Amanita muscaria collected during late summer and mid-fall. The aim of this study was to determine the concentrations of Pb and Cd in Amanita muscaria samples collected at different times of the year, compare the concentrations of these elements in samples with and without cap skin, and compare the obtained values to permissible limits in dietary supplements. A total of 44 Amanita muscaria samples were collected during three different harvesting periods (August, September, and October 2023) from Puszcza Biała, located approximately 80 km from Warsaw. The mushrooms were subjected to mineralization using concentrated nitric acid and hydrogen peroxide, followed by the determination of Pb and Cd concentrations using an atomic absorption spectrometer. Significant statistical differences were found in the Pb concentrations of samples collected in three different seasons (η2 = 0.67, p &lt; 0.001), with the concentration increasing progressively, reaching its highest value in October. Similarly, the Cd concentration also increased in the later collections, although the effect of time was weaker (η2 = 0.13, p = 0.03). No significant differences were observed in Pb and Cd concentrations between samples with and without cap skin. The average Cd concentrations in mushrooms were significantly higher than the permissible levels in dietary supplements; they were four times higher in August (p &lt; 0.001), six times higher in September (p &lt; 0.001), and nine times higher in October (p &lt; 0.001). The Pb concentration in the October samples was close to the permissible limit but did not exceed it in a statistically significant manner (p = 0.85). Due to the high Cd concentrations and potentially hazardous levels of Pb, the consumption of Amanita muscaria carries a significant risk of toxicity, which may lead to serious health hazards, particularly in the context of prolonged exposure.

Propidium Monoazide is Unreliable for Quantitative Live-Dead Molecular Assays.

Propidium monoazide (PMA) is a dye that distinguishes between live and dead cells in molecular assays like the Polymerase Chain Reaction (PCR). It works by cross-linking to the DNA of cells that have compromised membranes or extracellular DNA upon photoactivation, making the DNA inaccessible for amplification. Currently, PMA is used to detect viable pathogens and alleviate systemic bias in the microbiome analysis of samples using 16S rRNA gene sequencing. In these applications, treated samples consist of different amounts of dead bacteria and a range of bacterial strains, variables that can affect the performance of PMA and lead to inconsistent findings across various research studies. To evaluate the effectiveness of PMA, we used a sensitive qPCR assay and post-treatment sample concentration to determine PMA cross-linkage and activity accurately under varying sample conditions. We report that PMA is unreliable for viability assays when the concentration and composition of the bacterial mixtures are unknown. PMA is suitable only for qualitatively assessing viability in samples containing a known number of dead microbes or extracellular DNA.

Wastewater-Based Epidemiological Surveillance in France: The SUM’EAU Network

Wastewater surveillance is a powerful public health tool which gained global prominence during the COVID-19 pandemic. This article describes the development and implementation of the national wastewater surveillance network in France: SUM’EAU. Preliminary work included defining a sampling strategy, evaluating/optimising analytical methods, launching a call for tenders to select network laboratories and producing wastewater monitoring indicators. SUM’EAU was then deployed in three stages: (i) a pilot study, (ii) the transfer of analytical activities from the National Reference Laboratory to four selected network laboratories, and (iii) the extension of the system to additional sampling sites. Currently, SUM’EAU monitors SARS-CoV-2 across 54 wastewater treatment plants in mainland France. Once a week on business days, 24 h flow-proportional composite samples are collected at plant inlets and transported at 5 °C (±3 °C) to partner laboratories for analysis. The analytical process involves sample concentration, RNA extraction, and digital RT-PCR/q-RT-PCR to detect and quantify the presence of the SARS-CoV-2 genome in wastewater. Subsequently, data are transferred to Santé publique France, the French National Public Health Agency, for analysis and interpretation. While SUM’EAU has been instrumental in monitoring the COVID-19 pandemic and holds significant potential for broader application, securing sustainable funding for its operation remains a major challenge.

Bio-waste derived reduced graphene oxide (rGO) decorated Cr (III) doped α-Fe2O3 nanocomposite for selective ppm-level acetone sensing at room temperature: Potential approach towards non-invasive diagnosis of diabetic biomarker

Reduced graphene oxide (rGO) was synthesized via reduction of graphitized household tea-waste utilizing neem leaves extract. The synergistic effect of rGO decoration and Cr3+ doping within pristine Fe2O3 enhanced surface adsorption property, defect density, and oxygen vacancies, facilitating the detection of ppm-levels (1 to 10 ppm) acetone at room temperature. Noticeably, the formation of ‘inversion space-charge-layer’ on sensing material surface at lower operating temperature resulted p-type sensing response using n-type nanomaterial that was transformed to n-type response when the operating temperature was elevated. The maximum sensing response (Rg/Ra) ~ 6.8 towards ~ 10 ppm acetone was obtained from optimized rGO decorated Cr3+ doped Fe2O3 sensor (FC3R3) at ambient condition. This sensor also revealed a rapid response/recovery time (~ 10 s/ ~ 10 s) and was able to detect as low as ~ 1 ppm acetone. The sensor exhibited improved selectivity towards acetone over other interfering VOCs, attributed to significant dipole moment, low bond dissociation energy, and strong affinity of acetone towards surface-adsorbed oxygenated ions. Notably, the sensor showed negligible deterioration in sensing performance even after ~ 150 days. Furthermore, this sensor was capable to differentiate between acetone concentration in breath sample of healthy and diabetic person for non-invasive diabetes detection.

Fly ash stabilised red mud as a one-part alkali-activated sustainable material for pavement subgrade: Strength, durability and life cycle assessment analysis

In this study, the viability of using red mud (RM) as an alkali source and fly ash (FA) as an aluminosilicate source for making all waste-based one-part alkali-activated material without commercial activators for pavement subgrade has been evaluated. The study reveals that the UCS and CBR increase with the increase in FA percentage up to 40% and then decrease. UCS of RM increases from 0.31 MPa to 1.17, 1.56, 2.12, and 1.71 MPa for 20%, 30%, 40%, and 50%, respectively. One-part alkali-activated RM-FA with 30% FA was identified as the optimum mixture. Microlevel investigation reveals the formation of N-A-S-H and C-S-H. The resilient modulus (Mr) was found to be 80 MPa for 30% FA sample cured for 28 days. The heavy metal concentration in one-part alkali-activated RM-FA samples is within the acceptable limit. The environmental impact assessment shows the one-part alkali-activated RM-FA to be an environmentally friendly pavement subgrade material.

Organic Farming Is an Important Way to Achieve Low Accumulation of Heavy Metals in Soil

In this study, the accumulation characteristics of As, Hg, Cd, Cr, and Pb in 63 soil samples from 28 organic farms in Beijing, China, were analyzed to investigate the risk of heavy metal pollution in organic agriculture, and the key related factors were evaluated. The results revealed that the As, Hg, Cd, Cr, and Pb concentrations in the soil samples were below the risk screening values and substantially lower than those in the soil under conventional agriculture. However, the coefficients of variation for Hg and Cd were 112.45% and 38.34%, respectively, indicating a notable anthropogenic impact. Notably, 35.92% of the sampling sites had medium to high potential ecological risk values for Cd, and the Cd concentration increased considerably as the number of planting years increased. Different crop types impacted the soil heavy metal concentrations. The concentrations of Cd and As in the soil of Brassica crops were 0.265 and 12.915 mg/kg, respectively, which were substantially higher than those in the soil of other crop types. The Random Forest model indicated that soil nutrients had the most significant impact on soil heavy metal accumulation, particularly phosphorus. In conclusion, compared with conventional agriculture, organic agricultural soils have lower heavy metal concentrations and exhibit lower ecological risks, with no significant heavy metal pollution detected. However, there is a risk of Cd accumulation, and preventive measures should be implemented, especially for soils under prolonged cultivation and with potential sources of heavy Cd inputs.

Physicochemical and Spatial Distributions of Trace Elements and Organochlorine Compounds in Lake Idku Water, Egypt

This study aimed to characterize the water quality of 4 sites in Lake Idku, the third largest wetland region in Egypt regarding the physicochemical indicators, the spatial distributions of certain trace elements and organochlorine compounds (OCs). Most of the tested water quality indicators were above the permissible limits of River Nile water except nitrate was lower than the permissible limits. The distribution and concentrations of Fe, Cu, Zn, Mn, Pb, and Cd significantly differed (p > 0.05) among the sampling sites, where mean concentrations of these trace elements in all the tested sites ranged from 0.0226–0.0392, 0.010–0.098, 0.3570–1.0160, 0.084–0.942, 0.015–0.024, and 0.011–0.023 mg/L, respectively. The west site of the lake contained the highest contents of the trace elements, followed by the east, north, and then south sites. Water collected from the south site had the highest concentrations of Fe and Cu, while those collected from the west site had the highest concentrations of Zn, Pb, and Cd, and samples from the east site had the highest concentrations of Mn. The concentrations of Cu, Zn, Pb, Cd, and Mn in all samples which exceeded the Egyptian regulations, except those collected from the south site which contained levels of Mn that met the regulations. Regarding the residues of OCs, the ∑OCs can be grouped in descending order as follows: north site > east site > west site > south site, with values of 5.632, 5.230, 4.731, and 4.650 µg/L, respectively. All the detected OCs were above the maximum acceptable levels as compared to WHO standards of 0.1 μg/L, except for p,p'-DDT, p,p'-DDD, and p,p'-DDE which were at lower levels. In conclusion, the water quality of Lake Idku may at risk to biota and humans, monitoring, management, and mitigation strategies are urgently required to prevent further pollution by restricting the discharge of industrial and agricultural wastewater into Lake Idku.

Hybridizing Fabrications of Gd-CeO2 Thin Films Prepared by EPD and SILAR-A+ for Solid Electrolytes

Thin films of gadolinium-doped ceria (GDC) nanoparticles were fabricated as electrolytes for low-temperature solid oxide fuel cells (SOFCs) by combining electrophoretic deposition (EPD) and the successive ionic layer adsorption and reaction-air spray plus (SILAR-A+) method. The Ce1−xGdxO2−x/2 solid solution was synthesized using hydrothermal (HY) and solid-state (SS) procedures to produce high-quality GDC nanoparticles suitable for EPD fabrication. The crystalline structure, cell parameters, and phases of the GDC products were analyzed using X-ray diffraction. Variations in oxygen vacancy concentrations in the GDC samples were achieved through the two synthetic methods. The ionic conductivities of pressed pellets from the HY, SS, and commercial G0.2DC samples, measured at 150 °C, were 0.6 × 10−6, 2.6 × 10−6, and 2.9 × 10−6 S/cm, respectively. These values were determined using electrochemical impedance spectroscopy (EIS) with a simplified equivalent circuit method. The morphologies of G0.2DC thin films prepared via EPD and SILAR-A+ processes were characterized, with particular attention to surface cracking. Crack-free GDC thin films, approximately 730–1200 nm thick, were successfully fabricated on conductive substrates through the hybridization of EPD and SILAR-A+, followed by hydrothermal annealing. EIS and ionic conductivity (1.39 × 10⁻⁹ S/cm) measurements of the G0.2DC thin films with thicknesses of 733 nm were performed at 300 °C.

Pharmacokinetics of Hydrogen During Hydrogen-Saturated Saline Infusion in Pigs.

Background: Hydrogen gas (H2) has been shown to be effective in the treatment of various clinical conditions, from acute illnesses to chronic illnesses. However, its clinical indications and the corresponding appropriate hydrogen delivery methods have yet to be determined. This is due to the fact that the pharmacokinetics and pharmacodynamics of hydrogen in each delivery method have not been experimentally proven. Here, we verified the pharmacokinetics of hydrogen after the infusion of hydrogen-saturated saline. Methods: Hydrogen-saturated saline was prepared and checked for sterility and component specifications. Hydrogen-saturated saline was administered intravenously (125 mL/h) through the left internal jugular vein of pigs, and the blood hydrogen concentration was measured over time. Results: It was confirmed that hydrogen can be safely mixed under pressure into intravenous solutions (pharmaceutical products) without the contamination of foreign substances by using a needle-less vial access cannula. No change in the PH or composition of the solution was observed due to hydrogen filling. The hydrogen concentrations of blood samples collected from the left internal jugular vein 3 cm to the heart from the tip of the infusion line were 6.4 (30 min), 4.7 (60 min), 4.9 (90 min), and 5.3 (120 min) ppb w/w, respectively. The hydrogen concentrations of blood samples collected from the right atrium were 0.7 (30 min), 0.5 (60 min), 0.7 (90 min), and 0.7 (120 min) ppb, respectively. The hydrogen concentration of blood samples collected from the right internal carotid artery were 0.1 (pre), 0.2 (30 min), 0.3 (60 min), 0.0 (90 min), and 0.0 (120 min) ppb w/w, respectively. Conclusions: We confirmed that hydrogen could be safely pressurized and filled into intravenous (pharmaceutical) solution without contamination by foreign objects using a needle-free vial access cannula. When saturated hydrogen saline was dripped intravenously, almost all of the hydrogen was expelled during its passage through the lungs and could not be supplied to the arterial side.

Determining the Rates of α-Tocopherol Movement in DPPC Vesicles Using Small Angle Neutron Scattering.

α-Tocopherol (αtoc, vitamin E) is an essential nutrient sufficiently acquired through a balanced diet. This fat-soluble vitamin is most known for its antioxidative properties, however, its fundamental mechanism of action in cellular membranes remains unknown. To this end, we use time-resolved small angle neutron scattering (TR-SANS) and a contrast matching scheme to determine intervesicular exchange (kex) and intrabilayer flip-flop (kf) rates of αtoc in 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) vesicles. Moreover, we investigate the role of vesicle concentration and various types of cyclodextrins in affecting these rates. For the 25 mg/mL sample concentration it was determined that kex and kf were 1.35 ± 0.03 x 10-3 min-1 and 0.54 ± 0.10 x 10-3 min-1, which represent half-lives (T1/2) of 513.4 ± 11.7 min and 1285.1 ± 242.7 min, respectively. Differential scanning calorimetry confirmed the observed timescales of αtoc movement.

MX/MWCNTs composite material aids new strategy for HBV-DNA electrochemical biosensor: achieving multi-level signal amplification and unlabeled detection

Hepatitis B virus DNA (HBV-DNA) serves as a crucial biomarker for the detection of the hepatitis B virus, with variations in its concentration in blood samples providing vital insights into patient infection and recovery status. We have developed an electrochemical biosensor tailored for HBV-DNA detection, exhibiting high sensitivity, specificity, and a broad detection range. The biosensor utilizes a composite material composed of MXene and multiwalled carbon nanotubes (MX/MWCNTs), prepared through a hand-shaking self-assembly technique, to modify the glassy carbon electrode (GCE) and serve as signal receivers. A meticulously designed padlock probe DNA specifically recognizes HBV-DNA and forms a double-stranded DNA structure, which is subsequently degraded by exonuclease III. The resulting sequence then hybridizes with a PolyT-primer to create template, triggering rolling circle amplification and releasing a substantial amount of pyrophosphate for the initial level of signal amplification. Subsequently, the pyrophosphate induces the release of methylene blue (MB) from MB@ZIF-90 composite, achieving a second level of signal amplification. The released MB is then adsorbed by the MX/MWNCNTs-modified GCE, which possesses cationic dye adsorption capabilities and a large specific surface area, generating a detection signal and completing the third level of amplification. This biosensor offers a detection range spanning from 1.0 pM to 1.0 × 106 pM, with a remarkable detection limit as low as 0.5 pM (3σ/S), and is capable of distinguishing base mismatches. Furthermore, it has demonstrated excellent specificity and recovery performance in serum testing. The performance of this biosensor demonstrates significant potential for clinical application, with the ultimate goal of improving the diagnosis and management of hepatitis B.Graphical

Retrospective analysis of hepatic copper concentrations in an internal feeding colony of dogs fed a broad range of foods.

To examine the effects of age, sex, year of death/sample collection, and liver histopathology on liver copper concentrations in dogs fed a wide variety of commercial dog foods throughout their lives. This study utilized all bioarchived liver samples collected during necropsy at time of death from 2006 to 2022 from dogs housed in a closed feeding colony. Liver samples were analyzed on a dry matter basis for copper concentration by inductively coupled plasma-optical emission spectrometry and did not require specific criteria for selection. The effects of animal age, year of death/collection, sex, and liver histopathology on liver copper concentrations were assessed. Liver samples were analyzed from 296 dogs. Age and sex had no effect on liver copper concentrations, which increased linearly over time by an average of 3.41 ppm per year but remained within the normal reference range. Quantile regression indicated that the lowest 5% and highest 5% of liver copper concentrations analyzed were not changing and only a slight increase (3.7 ppm per year) was observed in the lower 25th quantile. The mean copper concentration of abnormal liver histopathology samples was not different from the mean copper concentration of normal liver histopathology samples. Histopathologic findings or animal demographic did not impact liver copper concentrations over a 16-year period. Liver copper concentration increased linearly but remained within the normal reference range. Mean liver copper concentrations for each year remained within normal limits. Studies assessing the impact of specific nutrient profiles and sources in various populations are warranted.

Pharmacokinetics of 7,8-dihydroxyflavone in neonatal mice with hypoxia-ischemia related brain injury

Introduction7,8-Dihydroxyflavone (7,8-DHF) is a promising translational therapy in several brain injury models, including the neonatal hypoxia-ischemia (HI) model in mice. However, the neuroprotective effect of 7,8-DHF was only observed in female, but not male, neonatal mice with HI brain injury. It is unknown whether HI-induced physiological changes affect brain distribution of 7,8-DHF differently for male versus female mice. We aimed to evaluate the impact of sex on the pharmacokinetics of 7,8-DHF in plasma and brain neonatal mice following experimentally induced HI brain injury.MethodsLeft-sided HI brain injury was induced in postnatal day 9 (P9) mice, followed by a 5 mg/kg intraperitoneal injection of 7,8-DHF. A liquid chromatography-tandem mass spectrometry method was developed to quantitate the drug concentration in plasma samples, as well as in samples from the left and right brain hemispheres. A nonlinear mixed-effects model was used to analyze the plasma and brain concentration-time data. A semi-quantitative approach was used to evaluate the concentrations of two active O-methylated metabolites of 7,8-DHF (8H7M-flavone and 7H8M-flavone) in both plasma and brain samples.ResultsOur PK analyses show that plasma 7,8-DHF concentrations followed a two-compartment PK model, with more than 95% eliminated by 3 h after the IP injection. Sex was not significantly associated with the PK of 7,8-DHF; however, HI brain injury was associated with a 21% reduction in clearance (p &amp;lt; 0.01). The distribution of 7,8-DHF to the brain was rapid; however, the extent of brain distribution was low with the right and left brain-to-plasma partition coefficients being 8.6% and 9.9%, respectively. Additionally, both O-methylated metabolites of 7,8-DHF were detected in the plasma and brain.ConclusionThe plasma and brain PK of 7,8-DHF in neonatal mice were similar between males and females. The low extent of 7,8-DHF brain distribution and the potential effects of the active metabolites should be considered in future studies evaluating the therapeutic effects of 7,8-DHF.

Cd2+ Mediated AuNCs for Simultaneous Detection of L-cysteine and Homocysteine

Background: L-cysteine (L-Cys) and homocysteine (Hcy) are the most representative of biothiol, which exist widely in organisms. L-Cys is one of the essential amino acids, which can be absorbed from protein-rich food and plays a considerable role in various physiological processes. Hcy is a vital intermediate in normal mammalian metabolism of methionine but does not occur in the diet. Therefore, it is significant to exploit a rapid and sensitive strategy to measure L-Cys and Hcy. Methods: Herein, we designed an “on-on” fluorescent platform for detecting L-Cys and Hcy with gold nanoclusters (AuNCs) as probes. During the sensing process, cadmium ions (Cd2+) acted as mediating substances to connected AuNCs and L-Cys (or Hcy), and triggered aggregation-induced emission (AIE) effect. Results: The linear ranges achieved with fluorimetry of L-Cys and Hcy were 0.1-10.0 μM and 0.1- 20.0 μM, respectively. Moreover, this fluorescent probe was successfully used to determine the LCys concentration in actual samples, and showed excellent recovery. Conclusion: Furthermore, the mechanism for sensing L-Cys and Hcy has been exhaustively investigated.

A Dual-Cycle Isothermal Amplification Method for microRNA Detection: Combination of a Duplex-Specific Nuclease Enzyme-Driven DNA Walker with Improved Catalytic Hairpin Assembly.

The association between microRNAs and various diseases, especially cancer, has been established in recent years, indicating that miRNAs can potentially serve as biomarkers for these diseases. Determining miRNA concentrations in biological samples is crucial for disease diagnosis. Nevertheless, the stem-loop reverse transcription quantitative PCR method, the gold standard for detecting miRNA, has great challenges in terms of high costs and enzyme limitations when applied to clinical biological samples. In this study, an isothermal signal amplification method based on a duplex-specific nuclease (DSN) enzyme-driven DNA walker and an improved catalytic hairpin assembly (CHA) was designed for miRNA detection. First, biotin-triethylene glycol-modified trigger-releasable DNA probes were conjugated to the streptavidin-coated magnetic beads for recognizing the target miRNA. The DSN enzyme specifically hydrolyzes DNA strands when the DNA probe hybridizes with the targeted miRNA. This recycling process converts the input miRNA into short trigger fragments (catalysts). Finally, three hairpins of improved CHA are driven by this catalyst, resulting in the three-armed CHA products and a fluorescence signal as the output. This dual-cycle biosensor shows a good linear relationship in the detection of miR-21 and miR-141 over the final concentration range of 250 fM to 50 nM, presenting an excellent limit of detection (2.95 amol). This system was used to detect miR-21 and miR-141 in MCF-7 and 22RV1 cells, as well as in 1% human serum. This system can be used to evaluate the expression levels of miRNAs in different biological matrices for the clinical diagnosis and prognosis of different cancers.

Electrochemical Detection of Paracetamol in Real Samples Using Sensor Based on a Glassy Carbon Electrode Modified with Citosan@SiO₂-APTES Composite: Synthesis, Characterization and Analytical Applications

Abstract Paracetamol (PA), commonly known as acetaminophen, is used for a variety of therapeutic applications. However, excessive or inappropriate use can lead to liver and kidney damage, emphasizing the importance of accurate measurement of its concentration in biological samples. In this study, we developed a rapid, simple, and highly sensitive voltammetric method using chemically-modified electrodes to detect PA in complex matrices such as human serum and commercial solid formulations. A glassy carbon electrode was modified with a chitosan-silica nanoparticle composite functionalized with 3-aminopropyltriethoxysilane groups (chitosan@SiO₂-APTES). The properties of the modified electrode and PA detection were analyzed using cyclic voltammetry, differential pulse voltammetry, and electrochemical impedance spectroscopy. Kinetic studies provided further insight into the electrochemical behavior of the electrode and improved its characterization. With this method, detection and quantification limits of only 0.025 µM were achieved under optimized conditions. Furthermore, it was found that the ideal linear concentration range for PA detection is between 0.025 and 0.5 µM and between 0.5 and 2.5 µM. Thus, this approach is ideal for the accurate quantification of PA in reference tablet formulations and for the analysis of real samples for validation purposes.

Optimization of Solar Corrosion Fenton Reactor for the Recovery of Textile Wastewater: In Situ Release of Fe2+

A Solar Corrosion Fenton reactor (SCFr) was developed by packing an iron-carbon steel filament inside the reactor to enable the in situ release of Fe2+. A Box–Behnken experimental design was used to optimize the effect of HRT (20, 30, and 40 min), the mass ratios of the packed filament inside the reactor with respect to volume (0.1, 0.2, 0.3 w/v), and the peroxide dosage added (500, 1000, and 1500 mg/L), the response variables were the percentage removal of COD, color, and turbidity. The optimum conditions for SCFr were an HRT of 24.5 min, a ratio of 0.16 (0.0032 m2/L), and a peroxide dose of 1006.9 mg/L. The removal was 91.8%, 98.4%, and 87.3% COD, color, and turbidity, respectively. Without solar radiation, the percentage removal was reduced by 16.3%, 47.9%, and 34.0% in terms of COD, color, and turbidity, respectively. The concentration of Fe2+ released was 25.4 mg/L of Fe2+. Prolonged HRT increases Fe2+ concentration and turbidity, which increase COD. The oxidation kinetics were fitted to a Behnajady–Modirshahla–Ghanbery (BMG) model, which indicated a high oxidation rate that is reflective of low treatment times. The w/v ratio was the most significant factor; the release of Fe2+ was stimulated by UV radiation and the chloride concentration of wastewater, which prevents the formation of an oxide layer, thus allowing its continuous release, taking advantage of solar radiation and the pH and chloride concentration of the raw sample.

Fourier Transform Near-Infrared Spectroscopy (FT-NIR(S)) and artificial neural network for the quantitative detection of grape juice adulteration by the addition of apple juice

Grape juice is popular for its taste and nutritional value, but due to its high commercial value, it is sometimes adulterated with apple juice, which contains naturally occurring sorbitol. This study used Fourier Transform Near-Infrared Spectroscopy (FT-NIR) alongside Artificial Neural Networks (ANN) to detect sorbitol in grape juice, aiming to identify adulteration. Two key NIR spectral bands, 12400–7400 cm−1 and 6400–5500 cm−1, were strongly correlated with sorbitol concentration in adulterated samples. The combination of FT-NIR and ANN provided accurate quantification of sorbitol levels, demonstrating that this method is a promising tool for the rapid detection of adulteration in grape juice with apple juice.