Concentration Range Research Articles

Kerstinginone, a new flavanone derivative from Commiphora kerstingii Engl. (Burseraceae) with potent apoptosis-inducing activity and inhibition of AKT/mTOR signaling pathway in non-sensitive prostate cancer cells

Ethnopharmacological relevanceCommiphora kerstingii Engl is a tree which is 20-30 meters in height and commonly called “ararrabi” in Hausa. It is found in the Sahelian region (Cameroon, Chad, and Nigeria) where it is utilized for the treatment of several ailments including cancer. Aim of the studyThis study was aimed at investigating the chemical constituents and cytotoxic effect of extracts and isolates from the stem barks and leaves of C. kerstingii. Materials and MethodsUsing classical chromatography technique coupled with spectroscopic analysis and literature information, ten (10) compounds were isolated from C. kerstingii stem barks and leaves, out of which two [kerstingilactone (3) and kerstinginone (10)] were new. To evaluate their potential cytotoxic effect, the impact on cell viability, growth, and proliferation was assessed using MTT and CCK-8 assays. Cell death mechanisms were analyzed via flow cytometry, and Western blotting was utilized to examine the expression of specific regulatory proteins. Furthermore, anti-metastatic properties were investigated through assays on cell migration, adhesion, and chemotaxis. ResultsAmong the tested compounds, 2 (Masticadienonic Acid) and 10 (kerstinginone) exhibited significant dose-dependent inhibition of PC3 and LNCaP cell growth. Compound 2 displayed optimal inhibitory effects within a concentration range of 10 to 40 μg/mL, while compound 10 demonstrated potent growth inhibition at concentrations of 2.5-10 μg/mL. Both compounds suppressed cell proliferation and the formation of clones. Specifically, compound 2 induced apoptosis solely in the androgen-sensitive LNCaP prostate cancer cells, whereas compound 10 induced a stronger and concentration-dependent apoptotic response in both PC3 and LNCaP cells, resulting in approximately 50-70% apoptotic cells. It also induced potent cell migration/invasion arrest at concentrations ranging from 2.5 to 5 μg/ml and increased cell adhesion to the extracellular matrix. ConclusionKerstinginone exhibits potent cytotoxicity and apoptosis-inducing activity, making it a promising lead for discovering a new anticancer drug.

Activity coefficients of 3-amino-1-propanol and 2-amino-1-propanol in aqueous solutions from surface tension data

Surface tension of 3-amino-1-propanol and (RS)-2-Amino-1-propanol in aqueous solution were measured in the temperature range from 293.15 to 308.15 K at intervals of 5 K over the whole concentration range. The concentration dependence of surface tension for both amino alcohols aqueous solution shows a similar behavior to that observed for other polar solutes in water. The surface tension data of 3-amino-1-propanol and 2-amino-1-propanol at the selected temperatures were accurately described using the integral Gibbs adsorption equation, the virial equation, and the Langmuir-Gibbs equation of state. The activity coefficients γ for both solutes were determined using the virial equation and found to be unitary within the experimental uncertainty, which was confirmed by the accurate representation of the experimental data by the Langmuir Gibbs Equation of State (LGSEOS). The standard adsorption energy calculated for both solutes from the fitting parameters of LGSEOS to the experimental data indicates that (RS)-2-amino-1-propanol has a higher hydrophobic character and a greater tendency to migrate to the surface than 3-amino-1-propanol as shown by the more negative ΔGads0 values for this solute than for 3-amino-1-propanol.

Determination of vitamin D3 content in cod liver oil using column-switching technique.

To develop a two-dimensional liquid chromatography method to determine the content of vitamin D3 in cod liver oil preparations. The samples were prepared by saponification and extraction, and the content of vitamin D3 was determined by two-dimensional liquid chromatography with dual-pump-single-valve switching dual detectors. The chromatographic column, capture device, and detection wavelength were optimized; the linearity, system suitability, recovery rate, repeatability and sample stability of the method were investigated, and further validated in actual sample determination. A column switching two-dimensional chromatography method was developed. In the first dimensional chromatography, an Agilent PoroShell SB-C8 (50 mm×4.6 mm, 2.7 μm) column was used, and acetonitrile-water was used as mobile phase and gradiently eluted at a flow rate of 1.0 mL/min, the detection wavelength was 264 nm. An Agilent Zorbax SB-C18 (150 mm×3.0 mm,1.8 μm) column was used in the second dimensional chromatography, and acetonitrile was used as mobile phase at a flow rate of 0.42 mL/min, the detection wavelength was 264 nm. In determining content of Vitamin D3, there was a good linear relationship in the concentration range and the system suitability, recovery rate, repeatability and sample stability all met the verification requirements. The developed two-dimensional liquid chromatography method in the study is accurate, reproducible and simple, it can simultaneously separate pre-vitamin D3, trans-vitamin D3, vitamin D3, and tachysterol3, the baseline separation was achieved, indicating that it is worth promoting for application.

Next-Generation Optical Fiber Sensors: Gold Nanoparticle/Eu2O3-RGO Hybrid Coating for Phosphate Ion Detection

The investigation of optical sensors for the identification of particular ions is currently a highly active field of study. In this regard, gold nanoparticles (Au NPs) and rare-earth-doped materials, such as europium oxide (Eu2O3), are frequently employed due to their distinctive optical properties, which make them suitable for sensing applications. A cladding-modified optical fiber sensor coated with Eu2O3 modified reduced graphene oxide/tri-sodium citrate functionalized Au NPs is presented for phosphate ion sensing. The phosphate ion sensing of the optical fiber was studied for different tri-sodium citrate concentrations and different europium concentrations against a fixed concentration of phosphate ion. Upon the introduction of phosphate ions to the optical fiber sensor, a voltage shift is detected in all tested samples. The performance of the optical fiber sensor was evaluated throughout a wide range of phosphate ion concentrations, from 100 nM to 500 nM. The sensor's reaction to rising phosphate ion concentrations follows a polynomial pattern. Furthermore, selectivity experiments demonstrate that the optical fiber sensor displays a more pronounced response to phosphate ions when compared to various other ions, including potassium, ammonium, calcium, copper, manganese, magnesium, nitrate, sulfate, bromine, carbonate, chlorine, and others. The sensor characteristics like repeatability, response time variation, and stability were also studied.

Influence of Crosslinker on Aptamer Immobilization and Aptasensor Sensing Response for non-metallic surfaces

Aptasensors transduce the specific binding of the target biomolecules with an aptamer into a measurable signal and enable rapid detection of biomolecules. Aptamer immobilization on the sensing surface through covalent bonding is preferred as it ensures stable and repeatable attachment of the aptamers in the desired configuration. Previous sensing reports have utilized homo-bifunctional crosslinkers like glutaraldehyde to immobilize aptamers to amine-terminated surfaces, but the efficacy of attachment chemistries and their influence on sensor response have not been evaluated. Here, we compare sensing and immobilization density results for four separate crosslinkers – one homo-bifunctional and three hetero-bifunctional – to immobilize the Ebola soluble Glycoprotein (sGP) binding DNA aptamer on the amine-terminated non-metallic surfaces – nanoporous anodized alumina oxide (NAAO) membranes and polystyrene beads. In each case, the aptamer-functionalized NAAO membranes were exposed to a range of Ebola virus sGP concentrations to obtain sensing responses. Measured sensing responses were fit to the Langmuir-Hill’s equation. The maximum possible sensor response, , obtained for each attachment chemistry is compared to determine the effectiveness of the different attachment chemistries. We also used crosslinkers to attach radiolabeled aptamers to amine modified polystyrene particles to determine the attachment efficiency based on the acquired aptamer density on the particle for each crosslinker. Sensing and attachment efficiency results show that aptamer attachment on the sensor surface using a homo-bifunctional crosslinker led to inconsistent sensing response for sensing of sGP across experiments and lower aptamer densities on polystyrene particles. In contrast, the results from aptasensors with aptamers attached through hetero-bifunctional crosslinkers provided consistent sensing responses across experiments and higher aptamer densities on the surface.

Chemical magnetic field-assisted batch polishing method of 316L stainless steel

316L stainless steel has been extensively employed in the manufacturing of medical equipment and biomedical implants because of its good ductility, corrosion resistance and biocompatibility, etc. However, there has always been a non-neglected problem of low polishing precision and efficiency in the whole machining chain for such parts, hence, it is difficult to meet the batch demand of the market for 316L stainless steel with high-precision surface. Based on the principle of magnetic field-assisted batch polishing (MABP) proposed by our research team previously, a novel chemical magnetic field-assisted batch polishing (CMABP) method here is developed by adding chemical reagents (i.e., the mixture of oxalic acid and hydrogen peroxide) in the preparation process of regular magnetic brush, desiring and expecting to further realize the polishing of 316L stainless steel with higher precision and efficiency simultaneously. The preliminary experimental results demonstrated that the value of surface roughness Sa after CMABP became smaller and the material removal rate increased comparing to that after MABP, which did verify the potential advantage of the established CMABP approach. In detail, CMABP experiments with pH value and H2O2 concentration as variables were carried out quantitatively. The results suggested that, within the set range of pH value (from 2 to 7) and H2O2 concentration (from 0.3 wt.% to 2.0 wt.%), when pH was chosen as 4 and H2O2 concentration was adjusted as 2.0 wt.%, the value of Sa after CMABP was the minimum, which could be 38% lower than that of MABP approximately. Nonetheless, material removal rate reached to the maximum, which could be around 168% more than that after MABP, when pH and H2O2 concentration were determined as 3.0 and 2.0 wt.%, respectively. Additionally, the discrepancy between the chemical and the regular magnetic brushes were detected and analyzed comparatively both at macro and micro scales. Also, the products on the surface of 316L stainless steel, such as the weak-binding layer and the passive layer, were discovered and taken to interpret the experimental phenomena of the surface roughness and material removal rate varying with the content of chemical reagents in CMABP, thereby revealing the material removal mechanisms correspondingly and interestingly. This work is capable of providing valuable reference undoubtedly for batch precision polishing of 316L stainless steel and other significant functional materials.

Development of an enzyme-linked immunosorbent assay for newborns dried blood spot thyroglobulin.

Thyroglobulin (Tg) is a biomarker of iodine status. Newborn Tg is a more sensitive marker than neonatal TSH in detecting variations in iodine intake. This study aims to validate a Tg enzyme-linked immunosorbent assay (ELISA) for Tg determination on dried blood spots (DBS) in newborns. This study also set out to assess the stability of Tg and the influence of newborns' hematocrit on Tg determination. A commercially available ELISA Tg assay was adapted for use on DBS. DBS-Tg in cord blood were measured in 209 newborns delivered from healthy euthyroid pregnant women. Sensitivity, linearity, repeatability, and intermediate fidelity were determined using the appropriate standards and quality control materials. The limit of detection (LoD) of the DBS-Tg assay was 2.4 µg/L, and the limit of quantification (LoQ) was 5.8 µg/L. Repeatability and intermediate fidelity were 7.7-8.3% and 11.0-11.2%, respectively. The median cord plasma Tg and DBS-Tg values in newborns were not significantly different, 30.2 (21.3-44.4) µg/L and 31.6 (19.3-48.7) µg/L (p=0.48) with the ELISA respectively, and 76.5 (40.0-101.5) µg/L with the Elecsys assay with an R=0.88. DBS-Tg concentrations decrease with increasing hematocrit values (p<0.05). DBS-Tg values were stable at a concentration of 25 µg/L for 12 months at -20ºC and 4ºC. This DBS-Tg assay demonstrated good analytical performances over a wide range of Tg concentrations, suggesting it is well suited to detecting variations in Tg concentrations. Studies comparing populations with different prevalence of anemia should consider the effect of hematocrit on DBS-Tg determination. The availability of a DBS-Tg assay for newborns makes it possible to integrate iodine status monitoring with newborn screening for inherited metabolic diseases.

Study Investigates Hydrate Formation Risk in WAG Changeover Operations

_ This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper SPE 218101, “Investigating the Effect of Carbon Dioxide Concentration on Hydrate Formation Risk From Water-Alternating-Gas (WAG) Changeover Operations,” by Farzan Sahari Moghaddam, SPE, Majid Abedinzadegan Abdi, SPE, and Lesley A. James, SPE, Memorial University of Newfoundland. The paper has not been peer reviewed. _ Hydrate formation is a flow-assurance challenge for offshore oil and gas operations with subsea pipelines, wells, and tiebacks. In water-alternating-gas (WAG) operations, hydrates can form within the injection wells when switching from water to gas and vice versa. This study investigates hydrate formation in a WAG injection well under water-to-gas and gas-to-water changeover operations. Introduction Few previous studies have focused on hydrate formation in gas injection and production wells. Hydrate formation in a gas well under particular enhanced oil recovery techniques requires more attention. This study aims to investigate the changeover operations of water-to-gas and gas-to-water (well depth: 4096 m) and the effects of gas composition changes in terms of CO2 content (5–44 wt%) and thermodynamic inhibition (5 m3 methanol) after water injection. In terms of flow rates, injection rates of 2300–3800 m3/d for water and 1 million std m3/d for gas, which are applicable for offshore Newfoundland and Labrador (NL), are studied. The complete paper includes a discussion of past studies on hydrate formation in production and injection-gas systems. Methodology Two scenarios were simulated: water-to-gas changeover and gas-to-water changeover over a range of CO2 concentrations of 5–44 wt%. For operational parameters, up to 3 days of shut-in period was considered for the changeover operations. The water injection rate of 2300 m3/d and gas injection rate of 1 million std m3/d were considered. The rate was increased to find the injection rate that could provide full displacement of the water phase within less than 1 hour from a water-to-gas changeover operation. The same injection rate is maintained for other natural-gas cases with increased CO2 content by changing the compressor injection pressure. After modeling the fluid with an appropriate cubic equation of state, the fluid model file was imported to the dynamic multiphase flow simulator. A sample WAG well from offshore NL where hydrate formation was experienced was considered for the simulations. After finalizing the setup of the well, the simulation scenario was finalized according to the changeover operation and the operating conditions. A sensitivity analysis was conducted on various concentrations of CO2 (5–44 wt%) followed by conducting both water-to-gas and gas-to-water changeover operations in the transient multiphase simulator. Finally, hydrate formation in presence of methanol was simulated, and the resulting profiles of hydrate formation temperature minus fluid temperature, known as DTHYD, were compared. The well depth is 4096 m from the seabed, and tubing internal diameter is 0.16 m. The seabed depth is 124 m below mean sea level. The bottomhole is known as the zero depth on the DTHYD, holdup, density, and pressure profiles, and the wellhead is considered to be 4096 m above the bottomhole depth in these profiles. A methanol slug was injected directly into the well under a sea temperature of 3°C at the end of water injection and before the shut-in duration.

Modeling, Simulation, and Optimization of Multi-Stage Equilibrium Extraction of Phenolic Compounds from Grape Pomace

The seasonal nature of wine production results in the accumulation of significant quantities of grape pomace (GP) during harvest, presenting management challenges for wineries that traditionally regard this solid byproduct as low-value waste. However, extracting phenolic compounds (PCs) from GP offers a promising avenue for creating bioactive extracts for use in the food, pharmaceutical, and cosmetic industries. This study develops a mathematical model for predicting the total phenolic content (TPC) and total dissolved solids (TDS) in liquids obtained from multi-equilibrium-stage extraction processes using a 50% aqueous ethanol solution to recover PCs from Tannat GP. The model is applicable across a wide range of TPC and TDS concentrations in the liquid (0.2-45.4 gGAE/L for TPC and 1 to 118 g/L for TDS) and extraction temperatures between 30 and 70 °C. It is used to determine the optimal operational conditions of a Shanks extraction system, either to minimize fresh solvent consumption or to maximize selectivity for PCs extraction, achieving a desired extraction yield with a specified number of extraction vessels.

Effect of Ce co-doping on radiation resistance behavior and laser performance of Er/Yb/Ce co-doped high-phosphorous polarization-maintaining silica fiber

Er/Yb/Ce co-doped high-phosphorus silica fiber core glasses with varying Ce2O3 concentrations were prepared and systematically studied. Based on this research, optimized Er/Yb/Ce co-doped high-phosphorus polarization-maintaining silica fibers were subsequently fabricated using the modified chemical vapor deposition (MCVD) technique and hole drilling method. The study confirmed that there is an optimal range of Ce doping concentrations for spectral performance, Ce doping effectively suppressing the formation of P-related defects during X-ray irradiation, and the dynamic valence state transformation of Ce3+/Ce4+ ions during irradiation enhanced the radiation-resistant properties, as demonstrated through radiation-induced absorption (RIA), electron paramagnetic resonance (EPR), and L3-edge X-ray absorption near edge structure (XANES) spectra. The homemade fiber, with optimized element concentrations, exhibited high laser efficiency comparable to commercial high-power fibers. Furthermore, the radiation-induced background loss of the fiber was 0.16 dB/m under 60 krad γ-rays at a low dose rate of 100 rad/h, and the radiation-induced gain variation (RIGV) was 0.019 dB/krad.

Label-Free Electrochemical Sensor Sensitivity Enhancement Using Field Effect Transistors: Fluoride Ions for Fuel Cell Degradation Analysis

In the context of proton exchange membrane fuel cells, precise monitoring of fluoride ions in the effluent water is crucial. Associated with the fluoride ion accumulation, membrane degradation and reduction of fuel cell efficiency arise. This study focuses on developing extended gate field-effect transistors (EGFET) sensors for real-time monitoring of fluoride ion concentrations. High sensitivity and specificity in detecting the concentration of fluoride ions using both N-type (TN0702) and P-type (LP0701) metal-oxide-semiconductor field-effect transistors (MOSFET) were achieved. The transfer characteristics (Id vs Vgs) owere thoroughly examined across a range of fluoride concentrations from parts per million (ppm) to parts per billion (ppb). N-type MOSFET-based sensors showed a distinct decrease in drain current (Id) with increasing fluoride concentration. With fluoride concentrations changed, the P-type MOSFET exhibited a notable shift in the threshold voltage (Vgs). A robust linear relationship was observed on calibration curves with R2 values exceeding 0.90 between the natural logarithm of fluoride concentration (lnC) and gate-source voltage (Vgs). This work demonstrates that MOSFET can significantly enhance the sensitivity of electrochemical sensors without complex labeling processes. The improvement has a future in the miniaturization of cost-effective sensor systems for fuel cell applications, facilitating real-time performance and degradation monitoring.

The effect of medical face masks on inhalation risk of bacterial bioaerosols in hospital waste decontamination station

There is insufficient research on bioaerosols in hospital waste decontamination stations. This study aimed to investigate the effect of three-layer and N95 masks in reducing the inhalation risk of bacterial bioaerosols in a waste decontamination station at a teaching hospital. Active sampling was conducted on five different days at three locations: the yard, resting room, and autoclave room in three different modes: without a mask, with a three-layer mask, and with an N95 mask. Bacterial bioaerosols passing through the masks were identified using biochemical tests and polymerase chain reaction (PCR). The median concentration and interquartile range (IQR) of bacterial bioaerosols was 217.093 (230.174) colony-forming units per cubic meter (CFU/m3), which is higher than the recommended amount by Pan American Health Organization (PAHO). The resting room had high contamination levels, with a median (IQR) of 321.9 (793.529) CFU/m3 of bacterial bioaerosols. The maximum concentration of bioaerosols was also recorded in the same room (2443.282 CFU/m3). The concentration of bacterial bioaerosols differed significantly between using a three-layer or N95 mask and not using a mask (p-value < 0.001). The non-carcinogenic risk level was acceptable in all cases, except in the resting room without a mask (Hazard Quotient (HQ) = 2.07). The predominant bacteria were Gram-positive cocci (33.98%). Micrococci (three-layer mask = 51.28%, N95 mask = 50%) and Coagulase-negative Staphylococci (three-layer mask = 30.77%, N95 mask = 31.82%) were the most abundant bioaerosols passing through the masks. The results obtained are useful for managerial decisions in hospital waste decontamination stations to reduce exposure to bioaerosols and develop useful guidelines.

The preparation of SiO2/GO/PVA based hydrogel sensor and its application for rapid and sensitive detection of NH3

Gas sensors have received significant interest due to their miniaturization, low power consumption and high reliability. In this paper, hydrogel film with high sensing properties toward NH3 were prepared using silicon dioxide (SiO2), porous graphene oxide (GO) and polyvinyl alcohol (PVA). The morphology and structure of hydrogel were characterized by scanning electron microscopy (SEM), Fourier transform infrared spectra (FT-IR) and specific surface area analysis. Compared with the conventional gas sensors based on planar GO sheets, the prepared porous SiO2/GO/PVA based hydrogel sensor could be used to detect NH3 with low concentration (10 ppm) and wide range of 10-1000 ppm. At the same time, a high response rate of 118% and an ultra-fast recovery (12s) were achieved. Finally, a sensing mechanism for SiO2/GO/PVA based hydrogel film was proposed: NH3 was adsorbed onto the surface of the film through hydrogen bonding and then reacted with the oxygen negative ions on the surface of the film to form nitrogen oxides. After degassing, oxygen was adsorbed on the surface of the film again to form oxygen negative ions. In addition, the film could monitor the freshness of fish over a period of 0-7 days, where the correlation between the resistance change and TVB-N was as high as 0.975. This work demonstrates the effectiveness of porous SiO2/GO/PVA based hydrogel film in improving gas-sensitive properties, providing a viable solution for food freshness detection, contamination tracking, and hazardous substances monitoring, etc.

Indirect determination of free chlorine in seawater by cyclic voltammetry using graphite–epoxy composite electrode: Hydrogen adsorption capacity of graphite–epoxy composite is one–third of that of platinum

A new possibility of indirect determination of free chlorine using a graphite–epoxy composite(GEC) electrode instead of Pt disk electrode was suggested by interpreting the relationship between the peak current of the oxidation peak for hydrogen generated through water electrolysis in CV and the amount of the free chlorine. The linear response range of concentration was 0.06–0.2 mg∙L−1 with correlation coefficient of 0.9951 (n = 5) and the sensitivity of 1225 μA cm−2 mg−1 L. The limit of detection (LOD) calculated from the 3σ IUPAC criteria was 1.2 × 10−2 mg L−1. The relative standard deviation (RSD) to 0.06 mg L−1 was 4.65 %(n = 10). The results show that the amount of free chlorine in the disinfected seawater can be indirectly determined by using a GEC electrode without influence of interferences unlike a Pt disk electrode. On the other hand, in this paper, a new method is proposed to evaluate the relative hydrogen adsorption capacity by the sensitivity of GEC electrode compared with that of Pt disk electrode. During the investigation of the hydrogen adsorption on the surface of the working electrode, we obtained the result that the hydrogen adsorption capacity of GEC is one-third of that of platinum.

Green RP-HPLC method for the estimation of carfilzomib in bulk, protein nanocarriers and human plasma: Application of chemometrics and Monte-Carlo simulations

Carfilzomib is a tetrapeptide epoxyketone that has shown potential clinical outcomes in the treatment of multiple myeloma. However, inaccuracies in quantifying such peptide drug products have arisen due to poor stability, low solubility, time-consuming techniques, complex physicochemical properties, and use of non-green solvents with less recyclability. This provides a substantial urge to develop an ecological and sensitive analytical method for quantifying peptide drugs from matrix formulation and biological samples in early as well as lateral stages of product development in pharma industries. As a result, the study aimed to develop a robust ecological method for estimation of carfilzomib via Green RP-HPLC using analytical quality by design (AQbD) paradigms with specific application in protein nanoparticles and biological matrix. Initially, an appropriate wavelength for quantification of carfilzomib was chosen using principal component analysis (PCA) as a chemometric tool.Risk assessment followed by factor screening studies using 8-factor Placket-Burman Design aided in earmarking critical method parameters (CMPs) affecting critical analytical attributes (CAAs). Further, Central Composite Design (CCD) was employed for design space optimisation to demarcate optimum chromatographic conditions, which were corroborated for robustness using Monte-Carlo simulations. The method was validated as per ICH Q2 (R1), followed by quantifying the greenness of the method using Green Assessment tools. The method optimisation resulted in the optimal chromatographic conditions using Green RP-HPLC. The chromatographic system was equipped with a Phenomenex Aeris Peptide-XC C18 column (150 × 4.6 mm × 5 µm), and the mobile phase was composed of isopropanol:methanol:0.1 M PBS (pH 5.5 adjusted using 0.1 % formic acid) (35:45:20v/v), with a 1 ml/min flow rate at a 210 nm ʎmax. The optimised chromatographic conditions resulted in a short retention time (RT) of 4.95 mins, 0.87 tailing factor (TF), 4,875,122 peak area (PA), and 8995 theoretical plate count (TPC). The method demonstrated linearity in a wide range of concentrations (0.1–20 µg/ml) with a correlational coefficient of 0.997 and < 2 % RSD. The method unearthed a high precision rate with more than 95 % of drug recovery in protein nanoparticles and human plasma, thereby confirming the accuracy and sensitivity of the developed method. Chemometrics and Monte-Carlo simulations ratified the robustness and sensitivity of the developed analytical method of Carfilzomib with established greenness and a high degree of practical utility in protein-based nano formulations and human plasma matrix for life cycle product development.

Spreading of graphene oxide suspensions droplets on smooth surfaces

Understanding and predicting the spreading of droplets on solid surfaces is crucial in many applications such as printed electronics and spray coating where the fluid is a suspension and in general non-Newtonian. However, many models that predict the maximum spreading diameter usually only apply to Newtonian fluids. Here, we study experimentally and theoretically the maximum spreading diameter of graphene oxide suspension droplets impacting on a smooth surface for a wide range of concentrations and impact velocities (5≤We≤700, 30≤Re≤2000). As the particle concentration increases the rheological behavior changes from a viscous fluid to a shear-thinning yield stress fluid and the maximum spreading diameter decreases. The rheology for all concentrations is well described by a Herschel–Bulkley model that allows us to determine the characteristic viscosity and corresponding Reynolds number Re during spreading. Analogous to Newtonian fluids, the spreading ratio follows the Re1/5 scaling in the viscous spreading regime. Furthermore, we use this characteristic viscosity to develop an energy balance model that takes into account the viscous dissipation and change in surface energies to find the maximum spread diameter for a given impact velocity. The model contains one non-dimensional parameter α that encodes both the dynamic contact angle during spreading and the droplet shape at maximum spread. Our model is in good agreement with our data at all concentrations and agrees well with literature data on Newtonian fluids. Furthermore, the model gives the correct limits in the viscous and capillary regime and can be solved analytically for Newtonian fluids.

Biocidal polymer coatings based on porphyrin-modified epoxy-amine networks

For the first time, a pronounced biocidal activity of modified polymers with a porphyrin content of 21.4 μM (0.002 wt%) against Staphylococcus aureus was demonstrated. In order to develop new biocidal polymer coatings, a study was carried out on diglycidyl ether of bisphenol A (DGEBA) and porphyrin-modified oligomeric diamine systems. The study investigated the solubility of porphyrins in oligomers through experimental and theoretical means, using Van Krevelen's approach of additive group contributions. Fully cured epoxy-amine polymer materials modified with varied free-base tetraarylporphyrins were obtained. The materials were studied by means of thermogravimetry, differential scanning calorimetry, UV–Vis and fluorescence spectroscopy. The proposed approach to the formation of modified epoxy-amine materials allows preservation of the photophysical properties of porphyrins, including their photostability. The addition of modifiers in 4.28–21.4 μM range of concentrations makes it possible to keep the thermophysical and thermochemical properties of the polymer matrix.

Post mortem chiral analysis of MDMA and MDA in human blood and hair

Drug-related fatalities in the EU are predominantly associated with opioids. MDMA (Ecstasy) consumption results in fewer lethal intoxications despite its widespread use. This study investigates MDMA-related fatalities, focusing on enantiomer ratios of MDMA and its metabolite MDA to explore the role of metabolism in fatal outcomes.MDMA induces euphoria, increased empathy, and physiological effects such as tachycardia, hypertension, and hyperthermia. Metabolism mainly involves CYP1A2 and CYP2D6, with polymorphism of the latter influencing metabolism rates. Our institute observed several MDMA-related fatalities, which prompted an investigation into the potential role of inefficient drug metabolism in these cases.A novel quantitative chiral analysis method was developed and validated for MDMA, MDA, amphetamine and methamphetamine enantiomers in human blood. Analysis of post mortem blood samples from eleven MDMA-related fatalities exhibited a wide range of concentrations and enantiomer ratios. Variability in R/S MDMA ratios, however, could be linked to the time period of metabolism. Hair analysis revealed high MDMA concentrations in all segments, irrespective of prior drug abuse anamnesis. Therefore, hair analysis may not be suitable for the assessment of past drug use in ecstasy-related fatalities.The results indicated that elevated levels of the MDMA enantiomer are correlated with longer survival times in cases of intoxication. However, there was no clear evidence for slowed MDMA metabolism as a cause of lethal intoxications. While challenges remain due to the diversity of cases, this study contributes valuable insights into ecstasy intoxications, aiding future interpretation of post mortem analysis.

Suspicious of Acute Kidney Graft Rejection: Tacrolimus Pharmacokinetics Under Methylprednisolone Therapy.

Acute rejection remains one of the main complications in the first months after transplantation and may influence long-term outcomes. Tacrolimus has proven its usefulness in solid organ transplants and its monitoring through the application of pharmacokinetic concepts to optimize individual drug therapy. This research proposes to evaluate the tacrolimus pharmacokinetic parameters in patients suspected of acute kidney graft rejection under methylprednisolone pulse therapy. Eleven adult tacrolimus-treated renal recipients were selected from a prospective, single-arm, single-center cohort study, with suspicion of acute rejection although in use of methylprednisolone pulses therapy. They were followed up for three months posttransplantation, being tacrolimus trough serum concentrations determined using a chemiluminescent magnetic immunoassay, and pharmacokinetic parameters were estimated by using a nonlinear mixed-effects model implemented by Monolix 2020R1. A tacrolimus trough serum concentration range of 8 to 12 ng.mL-1 was considered therapeutic. Six patients showed acute cellular rejection, and two of them in addition had an antibody- mediated rejection. Tacrolimus trough serum concentration was below the reference range in eight patients. Most patients showed a high tacrolimus concentration intrapatient and pharmacokinetic parameters variability. The obtained pharmacokinetics parameters helped in understanding the kidney recipient patients' tacrolimus behavior, assisting in the improvement of individual drug therapy and reducing the risk of acute rejection episodes.

In-situ grown NiFeLDH nanosheets over nitrogen rich amorphous carbon nanotubes: An electrochemical sensing platform for the detection of depression biomarker

In this work, intrinsic conductivity mismatch of NiFe layered double hydroxide (NFL) catalysts and agglomeration of nanosheets were addressed by introducing N doped carbon nanotubes (NCNTs) which improves catalytic activity. Using a one-step wet chemical process, CNT-supported NiFeLDH nanosheets (NFL/NCNTx, x=20, 50 and 100) were effectively created. This work delves into the lower level sensitive electrochemical detection of serotonin (5-HT) by utilising synergy of CNT and LDH. The modified NFL/NCNT exhibits better electrochemical activity, appreciable sensitivity and spanned a concentration range of 0.01 - 400 μM with detection limit stood at 1.2 nM due to the plethora of electrochemical active surface area, remarkable conductivity and appreciable stability. Impressively, 96.0 - 96.8 % and 96.7 - 97.2 % recovery rates achieved in human urine and serum samples were well close to HPLC data, signifying its feasibility for real-time monitoring. The operational stability of the proposed sensor retained up to 89.13 % for 6 weeks. The present study highlights that tailoring NFL-NCNT heterojunction is an important strategy for the development of active and stable sensing platform.