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The results confirm that the fluorescence method is a reliable tool for detecting endogenous esterase in living biological system.Bio-analytical, nano-quantitative spectrofluorimetric estimation of two non-classical β-lactam antibiotics; meropenem (MP) and ertapenem (EP) is presented. The method is based on the enhancement of the fluorescence intensity of MP-Eu3+/EP-Eu3+ with silver nanoparticles (AgNPs). AgNPs were synthesized and characterized by UV and transmission electron microscope (TEM). The plasmon resonance produced an intense absorption maximum at 398.0 nm. TEM micrograph showed the particle morphology with an average particles size of 13.0 ± 2.95 nm. The fluorescence intensities were measured against blank reagents at λem of 396.0 nm and 405.0 nm after excitation at λex 305.0 nm and 303.0 nm for MP and EP, respectively. Under optimum conditions, the relative fluorescence intensity showed a good linear relationship with the concentration ranges of 4.0-14.0 and 4.0 -12.0 ng/mL with excellent correlation coefficients of 0.9998 and 0.9997, and limit of detection of 0.84 and 0.86 ng/mL for MP and EP, respectively. The method was successfully applied for direct analysis of MP and EP in their drug substances and pharmaceutical vials. The significant, sensitivity and practicality of the method facilitated MP detection in real plasma samples. Bio-analytical validation was performed according to FDA. The method was rectilinear over the ranges of, 5.0 -75.0 μg/mL plasma. Interestingly, this described system has a promising benefit for various applications exploiting the dramatically enhanced-fluorescence occurrence.Hyaluronidase (HAase) is an important enzyme involved in a promoting inflammation pathway. Flavonoids are a group of major polyphenols including flavonols (such as myricetin and rutin), dihydroflavones (such as naringin and hesperidin), and isoflavones (such as genistein and puerarin), which have been proved to possess anti-inflammatory effects. In this study, the binding of the six flavonoids to HAase was investigated by steady state and time-resolved fluorescence, circular dichroism (CD) spectroscopy and molecular docking methods. Fluorescence data reveal that the fluorescence quenching mechanism of HAase by flavonoids is all static quenching procedure regardless of their core structure. The binding affinity is strongest for rutin and ranks in the order rutin > hesperidin > myricetin > puerarin > genistein > naringin. The thermodynamic analysis implies that hydrophobic interaction, electrostatic force and hydrogen bonding are the main interaction forces. find more Synchronous fluorescence spectroscopy and CD spectroscopy indicate that flavonoids have the same core structure and have similar effects on the microenvironment around Trp and Tyr residues and the secondary structure of HAase. The results of molecular docking show that the binding of flavonoids with the catalytic amino acid residues of HAase may lead to the decrease of enzyme activity.A novel Zn(II) complex of 6-ClpicH and picH was synthesized and its structure was determined by XRD technique. The detailed experimental optical susceptibility and band gap, refractive index, linear polarizability, optical and electrical conductivity parameters in various concentrations were investigated by means of the UV-Vis spectroscopic data. The optical band gap, refractive index (n), linear optical susceptibility (χ(1)), third-order nonlinear optical susceptibility (χ(3)), second- and third-order nonlinear optical (β and γ) parameters were examined by using DFT/M06-L and ωB97XD/6-311++G(d,p) levels. The IC50 value of Zn(II) complex against α-glucosidase was also obtained at 0.44 mM. The experimental band gap of the Zn(II) complex at 13, 33, 44 and 94 µM concentrations in ethanol were found to be 4.38, 4.37, 4.35 and 4.28 eV, respectively. The third-order NLO susceptibility χ(3) parameter at 94 µM concentration corresponding to the photon energies of 4.6 and 5.7 eV in the UV-Vis region were observed at 206.6 × 10-13 and 294.3 × 10-13 esu, respectively. Besides, the theoretical χ(3) values were obtained at 50.58 × 10-13 and 20.37 × 10-13 esu by using M06-L level. These results indicate that Zn(II) complex could be an effective third-order NLO candidate material. In brief, the detailed theoretical and experimental structural, spectral and optical properties of the Zn(II) complex were presented comparatively.Spectroscopic methods provide information on the spatial localization of biochemical components based on the analysis of vibrational spectra. Raman spectroscopy and Raman imaging can be used to analyze various types of human brain tumors and breast cancers. The objective of this study is to evaluate the Raman biomarkers to distinguish tumor types by Raman spectroscopy and Raman imaging. We have demonstrated that bands characteristic for carotenoids (1156 cm-1, 1520 cm-1), proteins (1004 cm-1), fatty acids (1444 cm-1, 1655 cm-1) and cytochrome (1585 cm-1) can be used as universal biomarkers to assess aggressiveness of human brain tumors. The sensitivity and specificity obtained from PLS-DA have been over 73%. Only for gliosarcoma WHO IV the specificity is lower and takes equal 50%. The presented results confirm clinical potential of Raman spectroscopy in oncological diagnostics.Visualizing endogenous histidine (His) in living systems is an important and challenging work in life science field. Herein, two weak-emission iridium(III) complexes (IrL1 and IrL2) with solvent ligands (CH3CN) were designed and synthesized. It was found that IrL2 showed a better performance for detecting His with more remarkable fluorescence enhancement and lower limit of detection (LOD = 35 nM). Moreover, the recognitionmechanism was confirmed to be a substitution of solvent ligands by His. Importantly, probe IrL2 was applicable to visualize endogenous His in living cells and rat tissue slices via an energy-dependent endocytotic pathway. We hope that this probe can serve as a useful tool for the diagnosis of His-related diseases.Recently, it is urgent to ameliorate the accumulation and quantification performances of surface-enhanced Raman scattering-based lateral flow immunoassay (SERS-based LFIA) to promote its reliable clinical application. Herein, a smart hydrophilic-hydrophobic SERS-based LFIA strip was demonstrated by decorating Ag nanoplates with hydrophilic surface onto the specific regions of hydrophobic polymethylmethacrylate (PMMA) film with Raman internal standard (IS), which can unexpectedly inhibit the "coffee-ring phenomenon". The target analytes were consequently enriched in the SERS-active Ag regions by the hydrophobic PMMA, considerably endowing the strip with amended quantitative monitoring ability. Aided by immunoprobes of flower-shaped Ag nanoplates, a limit of detection as 10 pg/mL and an outstanding correlation coefficient value (R2) of 0.992 for carcinoembryonic antigen (CEA) were obtained by utilizing this SERS-based LFIA strip, which can be conducive to clinical monitoring and will broaden the field of vision for the point-of-care diagnostic technique.Herein, we report a ratiometric fluorescent probe based on in situ incorporation of both Gold nanoclusters (AuNCs) and Green emitting carbon dots (gCDs) into zeolitic imidazolate framework-8 (ZIF-8) to analysis of Cephalexin (CFX). Under a single excitation wavelength of 400 nm, the sensor exhibits dual-emissions centered at 520 and 630 nm. The fluorescence of AuNCs (630 nm) is selectively quenched by CFX, whereas the fluorescence of gCDs (520 nm) remainsalmostconstant. The ratiometric fluorescence signal (F520/F630) of the prepared composite (gCDc/AuNCs @ ZIF-8) is linearly proportional to the concentration of CFX from 0.1 to 6 ng/mL with a low detection limit (LOD) of 0.04 ng/mL, which is below the maximum residues limit (MRL) of 100 ng/mL set by the Food and Drug Administration (FDA). Moreover, the designed sensing platform was successfully applied to detect CFX in the milk samples.A novel bifunctional-group multi-purpose dye probe p-TNS has been designed and synthesized. The probe p-TNS has unique excited-state intramolecular proton transfer (ESIPT) and resonance-assisted hydrogen bonding (RAHB) coupled system, was confirmed to detect cyanide and hydrazine by blocking the ESIPT effect. Cyanide can change the fluorescence of the solution from bright green to orange-red (116 nm Stokes shift), while hydrazine causes the bright green fluorescence to be quenched. The recognition mechanism of the probe p-TNS to CN- and N2H4 was proposed reasonably through spectral characterizations and theoretical calculations. Combined with theoretical calculations, it was speculated that the solvent dependence may be caused by the ICT effect in the molecule. The probe p-TNS could be prepared into test strips for the detection of cyanide and hydrazine. In addition, the probe molecule can also be used to detect trace amounts of cyanide in agricultural products, and respond to gaseous hydrazine by direct contact, indicating that the probe p-TNS has good practical application prospects. Therefore, this molecular framework provides a new way of thinking about detecting multiple target substances.The demand for gluten-free banana flour has led manufactures to enforce strict measures for quality control. A need has arisen for the development of more sensitive and reliable methods to test the quality of green banana flour (GBF). The objective of this study was to develop rapid visible to near-infrared (Vis-NIR) based spectroscopic models to detect gluten concentration, as a biomarker to detect wheat flour adulteration in green banana flour (GBF). Spectroscopic data were acquired using a desktop (FOSS®) Vis-NIR spectroscopy ranging from 400 to 2500 nm of the electromagnetic spectrum. The spectral and reference data were submitted to principal component analysis (PCA) and partial least squares regression (PLSR) for the development of gluten adulteration detection models. Calibration models were constructed based on a full cross-validation approach, consisting of 51 samples for the calibration set and 21 samples for the test set. PCA scores plot discriminated gluten adulterated and unadulterated GBF samples with 100% accuracy for the first two principal components (PCs). The optimal prediction model was obtained after a combination of baseline (offset and baseline linear correlation) and standard normal variate (SNV) pre-processing technique. This model showed a 94% coefficient of determination of cross-validation (R2cv) and prediction (R2p); root mean square error of cross-validation (RMSECV) of 3.7 mg/kg, root mean square error of prediction (RMSEP) of 3.9 mg/kg; and RPD value of 4. This work has demonstrated that Vis-NIRS method is a robust and feasible technology that may be used to ensure the safety of banana flour and that this product stays gluten-free by providing good and reliable gluten detection and quantification prediction models.In this think about, assurance of lopinavir and ritonavir down to organic concentration level has been carried out. The assurance is based on expanding the selectivity of the spectrofluorimetric procedure by combining both subordinate and synchronous spectrofluorimetric approaches, which allow effective estimation of lopinavir at 248.8 nm and ritonavir at 300.1 nm within the nearness of each other at Δλ of 60 nm. Worldwide Conference on Harmonization approval rules were taken after to completely approve the strategy, and linearity was gotten for the two drugs over the extend of 0.4-2.4 µg mL-1 for Lopinavir and 0.1-0.6 µg mL-1 for ritonavir. Application of of the strategy was successfully carried out within the commercial tablets with great understanding with the comparison strategies. As the detection limits were down to 0.133 and 0.022 µg mL-1 and quantitation limits were 0.395 and 0.068 µg mL-1 for lopinavir and ritonavir, individually; the in vivo assurance of lopinavir and ritonavir in spiked plasma tests was pertinent.
Homepage: https://www.selleckchem.com/Proteasome.html
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