Cyanopyridoimidazole/1,2-Aminothiol Click Reaction: A Novel Bioorthogonal Reaction for Synthesis of Radiotracers.

We herein described the design and synthesis of the cyanopyridoimidazoles (CPIs) as new bioorthogonal click reagents toward 1,2-aminothiol groups. Kinetic and density functional theory-based studies of the synthetic compounds revealed that incorporating an electron-withdrawing substituent into the CPI scaffold lowers its lowest unoccupied molecular orbital energy, consequently increasing reactivity. Optimized CPI 8a showed rapid reactivity and high stability in physiological conditions and has been demonstrated to be suitable for various radiotracer synthetic methods. Based on the new bioorthogonal reaction, a [67Ga]Ga-labeled prostate-specific membrane antigen-targeted probe was successfully prepared for in vivo imaging of prostate cancer in an animal model.

Monitoring dissolved organic matter in wastewater and drinking water treatments using spectroscopic analysis and ultra-high resolution mass spectrometry.

Dissolved organic matter (DOM) plays a critical role in determining the quality of wastewater and the safety of drinking water. This is the first review to compare two types of popular DOM monitoring techniques, including absorption spectroscopy and fluorescence excitation-emission matrices (EEMs) coupled with parallel factor analysis (PARAFAC) vs. Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS), for the applications in wastewater and drinking water treatments. The optical techniques provide a series of indices for tracking the quantity and quality of chromophoric and fluorescent DOM, while FT-ICR-MS is capable of identifying thousands of DOM compounds in wastewater and drinking water at the molecule level. Both types of monitoring techniques are increasingly used in studying DOM in wastewater and drinking water treatments. They provide valuable insights into the variability of DOM composition in wastewater and drinking water. The complexity and diversity of DOM highlight the challenges for effective water treatments. Different effects of various treatment processes on DOM are also assessed, which indicates that the information on DOM composition and its removal is key to optimize the treatment processes. Considering notable progress in advanced treatment processes and novel materials for removing DOM, it is important to continuously utilize these powerful monitoring tools for assessing the responses of different DOM constituents to a series of treatment processes, which can achieve an effective removal of DOM and the quality of treated water.

Effects of fish culture on particulate organic matter in a reservoir-type river as revealed by absorption spectroscopy and fluorescence EEM-PARAFAC.

Dam construction and fish culture can change the biogeochemical processes in river, yet their impact on the spectral properties of particulate organic matter (POM) remains to be studied. This was investigated in a reservoir-type river (Minjiang river, SE China) using absorption spectroscopy and fluorescence excitation-emission matrices-parallel factor analysis (EEMs-PARAFAC). Five fluorescent components were identified from POM with PARAFAC. Four components C1-C4 were affected by the seasonal variations of rainfall and runoff, indicating the influences of hydrological condition and terrestrial inputs. The Chlorophyll a concentration (Chl a) correlated significantly with the humic-like C3 (p < 0.05) and the protein-like C4 (p < 0.01), indicating phytoplankton was an important source of C3 and C4. The Chl a and fluorescence intensities of C3-C4 were higher in the fish culture zones than in other areas, and the absorption coefficient a300 and C1-C4 were lower downstream the dam. These results indicated that fish farming in the reservoir probably promoted the production of POM. The a300 and C1 per unit mass of suspended particulate matter (a300/TSM and C1/TSM) correlated significantly with the median particle size (p < 0.01), which might be related to the contribution of micro-phytoplankton. The absorption spectra of POM showed a shoulder peak at ∼280 nm, and its intensity correlated significantly and positively with Chl a (p < 0.01). These results indicated that the peak was probably derived from phytoplankton production. Our results have implications for better understanding the influences of human activities on the dynamics of river POM.

[Study on the Spiral-Torus Herriott Type Cell].

With the rapid development of social economy, the environmental pollution and the ecological destruction are continuously deteriorating while sudden environmental pollution incidents occur frequently. Real-time monitoring harmful gases of the air take advantages of spectroscopic techniques for concentration measurement. Multipass optical cells are -widely used in absorption spectrometry technique to improve gas detection sensitivity under the condition of weak absorption. This paper proposes a spiral-torus type multipass optical device base on the structure of Herriott type cell. The optical device consists of multiple torus concave mirrors in a spiral way. Incident light propagates along with radical and axial direction in winding staircase pattern. The faculae on the inner wall present a spiral-type. The entrance and exit apertures are separated due to the spiral trace of optical rays, which increases the accessible adjustment of the apparatus. The effective optical length can be adjusted based on the proportional relationship to the reflective times. This device is characterized with easy adjustment and excellent mechanical performance due to its cylindrical structure. Based on ABCD matrix, the stability of the system was analyzed and the relationship between the number of reflections and the incident angle were discussed. With optical simulation software, we designed a device for separating polarized light, and the characteristics of its rotation was studied.