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Mercury ion (Hg2+) is one of the most toxic heavy metal ions which will cause permanent damage to the brain and kidneys. So, it is important to develop a sensitive, simple and reliable approach to detect Hg2+. In this work, we report a surface-enhanced Raman scatting (SERS) sensor by decorating the inner wall of capillary with 4,4'-dipyridyl (Dpy) functionalized silver nanoparticles (AgNPs). The main advantage of this sensor is that it can collect samples directly by capillary force and carry out on-site analysis by combining portable Raman spectrometer. In the presence of Hg2+, the Dpy molecules would be separated from the surface of AgNPs and coordinated with Hg2+, resulting in a decrease in the SERS signal. A linear correlation of Raman intensity with Hg2+ concentrations from 1 to 100 part-per-billion (ppb) was obtained for quantitative analysis and the limit of detection (LOD) was determined to be 0.1 ppb. The good reproducibility and selectivity of the sensor were also demonstrated. In addition, the sensors were successfully applied to detect Hg2+ in real environmental water samples, and the sampling process provided operation convenience compared to conventional methods. These results indicated that these capillary sensors had great potential for Hg2+ detection in practical use. V.A well-designed naphthopyran-diaminomaleonitrile dyad (sensor 1) has been synthesized successfully, its molecular structure was well characterized by NMR and mass spectrometry. Sensor 1 exhibits excellent photochromic and photochromic fluorescence switch performance with reversible color change and good fatigue resistance upon alternating ultraviolet irradiation and thermal bleaching. In addition, sensor 1 displayed excellent fluorescent and colorimetric sensing ability towards Cu2+ ions with high selectivity and sensitivity. The addition of 5.0 equiv. of Cu2+ ions into sensor 1 (1 × 10-5) in CH3CN solution significantly quenched the fluorescence of sensor 1 by 80.0%. Furthermore, the addition of Cu2+ ions also caused the complete disappearance of the absorbance band at 350-450 nm in absorbance spectra of sensor 1 and accompanied by the distinct color change form yellow to colorless. Job's plot, mass spectrometry, 1H NMR titration and DFT calculations proved that sensing performance was attributed to the formation of 11 sensor 1-Cu2+complexes. Sensor 1 can monitor the existence of Cu2+ ions in living cells via the fluorescence images. Sensor 1 showed great potential applications as chemosensor and photochromic materials. Ficin has been reported to possess peroxidase activity, but its applications in some respects have been limited because of its relatively low activity. Herein, a mesoporous metal-organic framework, PCN-333(Fe), was synthesized, which was selected to encapsulate ficin to form ficin@PCN-333(Fe). Compared with ficin, the peroxidase-like activity of ficin@PCN-333(Fe) toward 3,3',5,5'-tetramethylbenzidine (TMB) oxidation was about 3 times increase in the presence of H2O2, and followed classical Michaelis-Menten model. The kinetic parameters showed that stronger affinity and higher catalytic constant (Kcat) of ficin@PCN-333(Fe) to both TMB and H2O2 compared with ficin, and Kcat of ficin@PCN-333(Fe) was increased by 3.65 folds and 3.59 folds for TMB and H2O2, respectively. Taking advantages of higher catalytic property of ficin@PCN-333(Fe), we developed a colorimetric method with high sensitivity and selectivity to detect glucose, which displayed a good linear response toward glucose in the range of 0.5-180 μM with a limit of detection of 97 nM. Furthermore, ficin@PCN-333(Fe) has been proven to successfully detect glucose in human serum, implying its great potentialities and wide applications as peroxidase mimics. In this paper, a series of Eu(III) complexes was designed using 2-thenoyltrifluoroacetone (TTA) as the first ligand, and phenanthroline derivatives as the second ligand. Their molecular structure was analyzed via their single crystals. Detailed photophysical analysis on these Eu(III) complexes suggested that ligand TTA was the major energy transfer antenna for emissive Eu(III). The phenanthroline-derived ligands showed low triplet levels (T1), leading to a reverse energy transfer (triplet trap) from Eu(III) 5D0 to T1 of diamine ligands. This procedure actually compromised emission performance of these Eu(III) complexes. It was found that halogen anions, especially fluorine ion, interacted with these diamine ligands, which heightened triplet level of these diamine ligands. With the elimination of such triplet trap in these Eu(III) complexes, their Eu(III) emission was greatly improved, showing emission turn-on effect. Detailed sensing performance was discussed carefully. Eu(TTA)3Phen showed a down-bending working curve following a two-site model Stern-Volmer equation. Eu(TTA)3DPPZ and Eu(TTA)3DPOX showed linear working curves with good selectivity. In addition to its emission turn-on sensing, Eu(TTA)3DPOX still showed ratiometric sensing. Detailed sensing mechanism was discussed and confirmed. this website V.BACKGROUND There is limited information regarding the daily shedding of JC virus (JCV) in urine and its correlation with serum JCV antibody levels. METHODS The dynamic expression of JCV in urine and its correlation with JCV antibody status in patients receiving disease modifying therapy for multiple sclerosis were examined in a longitudinal case-control study. JCV antibody index levels were determined using a two-step ELISA (Stratify). JCV shedding in urine samples was determined by quantitative PCR during two 30-day study periods separated by intervals of at least 6 months. RESULTS Of 42 study subjects (57% female; ages 22-56, average age 39.6 years), 27 (64.3%) were JCV antibody positive (index >0.40) at initial urine collection. Twelve seropositive subjects (44.4%) had detectable JCV in their urine with values ranging from 290 to 5.08 × 108 copies/mL. Daily viral shedding in these patients remained fairly constant throughout the study. Urinary JCV shedding was not detected in any JCV antibody index negative or indeterminate subject. In JCV urinary shedders, the average JCV antibody index was 2.69 (range 1.67-3.57). The average anti-JCV antibody index for the remaining JCV seropositive individuals without viral urinary shedding was 1.35 (range 0.46-3.91). CONCLUSION MS patients displayed a consistent pattern of JCV shedding over days and months in which higher levels of viruria appeared to have driven higher levels of JCV antibody index. The findings provide additional insights into the dynamic expression of JCV and host response; however, studies in larger populations and of longer duration will be needed to determine their significance to the development of progressive multifocal leukoencephalopathy (PML).
Read More: https://www.selleckchem.com/products/chir-99021-ct99021-hcl.html
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