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Crucial Physicochemical Determinants within the Anti-microbial Peptide RiLK1 Advertise Amphipathic Constructions.
These results demonstrate that FCS is a powerful tool for the rapid evaluation of the lipophilic probe behavior in heterogeneous ME solutions.A simple and fast microwave synthesis method was applied for the preparation of several carbon dots (CDs) from various combinations of urea, phosphoric acid, and B-alanine as nitrogen, phosphorus, and carbon precursors. The maximum quantum yield (44%) was obtained for nitrogen and phosphorus co-doped carbon dots (N, P-CDs) prepared from urea, B-alanine, and phosphoric acid. Furthermore, N, P-CDs were exploited to synthesize a simple and sensitive fluorometric probe to determine nifedipine (NFD). We determined that the analytical response of the designed sensor could be affected by the kind of dopant and synthesis precursors. It is worth mentioning that the fluorescence intensity of N, P-CDs was weakened by NFD, and no fluorescence quenching was observed for other prepared CDs. The NFD-developed sensor demonstrated a linear response range of 3.3 × 10-8-3.2 × 10-5 mol/L, with the detection limit of 1.0 × 10-8 mol/L. The sensor was successfully applied to measure NFD in human biological fluids.The functionalization of porous aromatic frameworks (PAFs) is essential for task-specific application of these materials as advanced adsorbents in water treatment. In this study, a carboxyl-functionalized PAF was prepared by the post-synthesis modification of a HOCH2-tagged PAF, which was synthesized from a precursor-designed method. check details The synthesized PAFs were comprehensively characterized. The targeted PAF-COOH showed hierarchical porosity with the coexistence of micropores and mesopores. The carboxyl groups were distributed homogeneously across the whole material, and its content was as high as 4.18 meq g-1. An equilibrium adsorption isotherms study demonstrated that the adsorption of cationic dyes fitted well to the Langmuir model and the maximum adsorption capacities of methylene blue (b-MB) and phenosafranine obtained at pH 10 were 775.19 and 588.24 mg g-1, respectively. The adsorption kinetics of cationic dyes followed the pseudo-second order kinetic model. Quick kinetics was demonstrated with the k2 for a 100 mg L-1 b-MB solution as high as 2.83 g mg-1 min-1 and the equilibrium time was just 0.5 min. In addition, the dye-loaded PAF-COOH could be regenerated easily and showed excellent reusability. These significant characters indicated a promising prospect of the PAF-COOH for water treatment.A REDOX-based analytical method was developed for determining the plutonium concentration. In this method, plutonium was oxidized to the +6-oxidation state using of ceric ammonium nitrate solution. The interference from ceric(IV) nitrate was suppressed by reducing its oxidation state from +4 to +3 with sodium nitrite. Hexavalent plutonium in this sample was then reduced to be tetravalent by adding a known volume of excess standard ferrous ammonium sulphate. The dichromate equivalence required for unreacted ferrous ammonium sulphate was determined to obtain the concentration of plutonium. Interference studies from chemicals envisaged to be present in the PUREX process stream, such as dissolved tri-n-butyl phosphate, uranium, and various reagents employed during analysis, were performed for the determination of plutonium concentration. The relative standard deviation was found and it is within ± 1.0% for an aliquot containing plutonium in a range of 0.7-2.5 mg.Chloramphenicol (CAP) is a kind of broad-spectrum antibiotic, which has been forbidden in food by most countries because of its side effects. In this study, a simple and low-cost biosensor for CAP detection in food was developed. The biosensor consisted of an aptamer specific to CAP and a pair of split probes that could self-assemble as DNAzyme. The detection result could be identified by the naked eye and the visual limit was 10 nM CAP. The absorbance of final reaction products at 417 nm had a linear relationship with the logarithm of the CAP concentration in a range from 10 to 200 nM, and the limit of detection was 87.3 pM. The visual analysis by imageJ also showed a linear detection range between 25 and 200 nM. The entire detection procedure could be completed in about 1.5 h at a cost of about 0.16 dollars per reaction. We believe that the biosensor shows great potential in the rapid and sensitive detection of CAP in food.Nifedipine is an antihypertensive chemical. The illegal addition of this chemical into Chinese traditional patent medicine (CTPM) is unstandardized and lacks regulation. It could bring serious side effects to patients, causing various symptoms. Therefore, accurate detection of nifedipine is very important for human health and the prevention of illegal additives. Surface-enhanced Raman spectroscopy (SERS) is a fast and sensitive fingerprint spectroscopic technique, which has been shown to be promising in drug detection. In this study, nifedipine in CTPM was determined qualitatively and quantitatively with SERS. Linear relationships between the concentrations of nifedipine and the intensities of the characteristic peaks were established. The results showed a linear relationship within the concentration range of 0.5-10 mg/L, and the lowest detectable concentration of nifedipine in CTPM was 0.1 mg/L (equivalent to 0.03% doping of nifedipine in CTPM). This method has shown a great potential in the detection of drugs illegally added to CTPM.Conventional enzyme-based glucose quantification approaches are not feasible due to their high cost, specific working temperatures, short shelf life, and poor stability. Therefore, a portable platform, which offers rapid response, cost-efficiency, and high sensitivity, is indispensable for the healthcare of diabetes. In this study, we proposed a portable platform incorporating gold (Au) and silver (Ag) nanoparticles (NPs) with a smartphone application based on machine learning for non-enzymatic glucose quantification. The color change obtained from the reaction of small and large Au/Ag NPs with glucose was captured using a smartphone camera to create a dataset for the training of machine-learning classifiers. Our custom-designed user-friendly smartphone application called "GlucoQuantifier" uses a cloud system to communicate with a remote server running a machine-learning classifier. Among the tested classifiers, linear discriminant analysis exhibits the best classification performance (93.63%) with small Au/Ag NPs and it demonstrates that incorporating Au/Ag NPs with machine learning under a smartphone application can be used for non-enzymatic glucose quantification.Bisphenol A (BPA) interferes with the reproduction and endocrine system of humans and wild animals. For the detection of BPA, a sensitive and rapid detection method was established. BPA was imprinted on the surface of Fe3O4 nanoparticles through dopamine self-polymerization. After the removal of BPA, molecularly imprinted microspheres with BPA recognition cavity were formed. The electrochemical impedance response increased with BPA embedded in the molecular imprinting layer. The electrochemical signal was proportional to the concentration of BPA with a linear range from 1 × 10-11 to 1 × 10-3 M and a detection limit of 5.78 × 10-12 M. The proposed biosensor was used to detect the BPA in vegetable oil indicating a promising application in food-field monitoring.Carnosine is a naturally occurring dipeptide and a functional component in foods, while also showing health-promoting effects. Generally, food-derived carnosine is quantified via high-performance liquid chromatography (HPLC). We have developed a method for quantifying carnosine in foods using microbial enzymes, β-Ala-Xaa dipeptidase (BapA) and histidine ammonia-lyase (HAL). The carnosine concentrations in extracts of chicken, pork, beef, bonito, and tuna were determined via both HPLC and enzymatic determination. The carnosine contents measured via enzymatic determination were in agreement with those determined via conventional HPLC analysis. Relative standard-deviation values of the conventional HPLC method and the enzymatic determination of carnosine in foods were 0.728-5.76% and 0.504-4.58%, respectively. The recovery of carnosine in food extracts via enzymatic determination was 97-103%. Therefore, the developed enzymatic determination technique using BapA and HAL can be used for the determination of carnosine in meats and fishes with comparable accuracy to that of conventional HPLC analysis.A bicomponent colorimetric probe based on carbon quantum dots (CQDs) and o-phenylenediamine (OPD) was established for the detection of Cu2+. Theoretically, light-generated electrons from CQDs were trapped by the dissolved oxygen, resulting in the production of superoxide radicals. The colorless OPD was oxidized by the superoxide radicals to its yellow oxidation product (OPDox). On the other hand, Cu2+ can bind onto the surface of CQDs and change the band gap of the CQDs. This change induces an inhibition of the photo-oxidation of OPD, thus resulting in a decrease of the absorbance of OPDox. The mechanism was demonstrated by a series of control experiments. The parameters influencing the sensing performance as well as potential interferences were investigated. Under the optimum conditions, a limit of detection of 30 nM was achieved. Moreover, this sensing system was applied to analyze Cu2+ in seawater and tapwater samples, and achieved satisfying results.Aptamers are widely used as a recognition element for Alzheimer's disease (AD)-related biomarker determinations. Due to the existing Cu2+ in real samples, and its possible coordinations with aptamers and biomarkers, the aptamer-based biomarker determination could be seriously disturbed. In this work, taking Aβ40 oligomer (Aβ40O, a typical biomarker for AD) as a model, the interference of Cu2+ in the interaction between Aβ40O and its aptamer (Apt) was investigated by surface plasmon resonance spectroscopy. The results demonstrated the binding of Cu2+ to Apt, resulting in significant changes on the original structure of Apt, and the affinity of Apt to Aβ40O. The affinity of Apt-Cu2+/Aβ40O-Cu2+ (Kd 1.36 µM) was 17 times weaker than that of Apt/Aβ40O (Kd 0.08 µM), which induced a poor dynamic range in the Cu2+-involved Aβ40O determination. The analysis of Aβ40O-spiked real samples revealed that the existing Cu2+ resulted in significant positive errors in CSF analysis, but also complicated errors in serum analysis that depended on the blood collection. Further studies confirmed that EDTA can completely chelate Cu2+ from Apt-Cu2+ and Aβ40O-Cu2+, eliminating the interference of Cu2+ on the Aβ40O/Apt system. Therefore, excess EDTA is highly recommended for Apt-based CSF and blood analysis, even if the samples are from EDTA- or other metal ion chelating agent-involved collection tubes. This work quantitatively revealed the interference of Cu2+ and provided a simple but effective approach to eliminate the interference, which will improve the existing method to achieve accurate Apt-based biomarker detection in real samples.A fabrication method of molding-type solid-phase extraction media (M-SPEM) bound with commercially available adhesive is presented. Six pieces of M-SPEM were prepared by heating each kneaded product of a particulate sorbent and an adhesive inserted into a six-hole cylindrical mold for hardening under an open system and normal pressure. The particulate sorbent contained in M-SPEM was divinylbenzene-based reversed-phase mode solid-phase extractants that we have reported. An examination of several adhesives showed that the moldability of M-SPEM depended on the composition and properties of the adhesive. The optimized procedure can be used to prepare an M-SPEM containing an 85 wt% particulate sorbent (particulate sorbent/adhesive, 100 mg/17 mg; particle diameter, 90-150 µm), and the M-SPEM has a specific surface area of about 500 m2/g. The established procedure in this study can bind particulate sorbents together, which showed almost no reductions in the adsorption property and liquid permeability compared with those of the particulate sorbent.
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