Reaction between Azidyl Radicals and Alkynes: A Straightforward Approach to NHâ 1,2,3â Triazoles

Reaction between nitrogenâ centered radicals and unsaturated Câ C bonds is an effective synthetic strategy for the construction of nitrogenâ containing molecules. Although the reactions between nitrogenâ centered radicals and alkenes have been studied extensively, their counterpart reactions with alkynes are extremely rare. Herein, the first example of reactions between azidyl radicals and alkynes is described. This reaction initiated an efficient cascade reaction involving interâ /intramolecular radical homolytic addition toward a Câ C triple bond and a hydrogenâ atom transfer step to offer a straightforward approach to NHâ 1,2,3â triazoles under mild reaction conditions. Both the internal and terminal alkynes work well for this transformation and some heterocyclic substituents on alkynes are compatible. This mechanistically distinct strategy overcomes the inherent limitations associated with azide anion chemistry and represents a rare example of reactions between a nitrogenâ centered radicals and alkynes.Get radical! Although the reactions between nitrogenâ centered radicals and alkenes have been studied extensively, their counterpart reactions with alkynes are extremely rare. Herein, the first example of reactions between azidyl radicals and alkynes is described (see scheme).Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/137186/1/chem201504515.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/137186/2/chem201504515-sup-0001-misc_information.pd

An efficient magnetic carbon-based solid acid treatment for corncob saccharification with high selectivity of xylose and enhanced enzymatic digestibility

An effective method for corncob saccharification was investigated over a magnetic carbon-based solid acid (MMCSA) catalyst in the aqueous phase. MMCSA was synthesized through a simple and inexpensive impregnation-carbonization-sulfonation process. Under the optimal reaction conditions (150 °C, 2 h, 0.5 g corncob, 0.5 g catalyst and 50 ml deionized water), 74.9% of xylose yield was directly obtained from corncob, with 91.7% cellulose retention in the residue. After reaction, the MMCSA was easily separated from the residue by an external magnet and reused 4 times showing high stability and catalytic activity. The enzymatic digestibility of the pretreated residue reached 95.2%, with a total sugar yield of 90.4%. The morphologic and structural properties of the natural and treated corncobs were analyzed primarily through 3D X-ray microscopy to characterize the cell wall thickness, porosity, and pore surface area distribution. The increase of macropores (pore surface areas > 200 μm2) was beneficial to the accessibility of cellulose to cellulosic enzymes, so the enzymatic digestibility was enhanced immediately. Compared with other traditional hydrolysis methods, this two-step hydrolysis approach represents an environmentally friendly and sustainable saccharification of lignocellulose to produce xylose and glucose while achieving the same level of reaction efficiency

MECHANICAL ANALYSIS OF HIGH-SPEED RAILWAY SLAB BALLASTLESS TRACK UNDER WORKING CONDITION

In order to study the mechanical properties of the ballastless track structure under the load of the train, this paper simplified the ballastless track structure to an infinite double-layer elastic beam. The double-layer elastic beam model and its theoretical expression formula was established using the elastic foundation beam concept. When the train was at a certain position on the rail, the differential balance equation between the rail and the concrete slab was established under the action of the vehicle load. Combined with the generalized “initial parameter method” and its boundary conditions, the analytical solution of the double-layer beam displacement and stress were obtained under the vehicle load. Through calculation examples, the displacement and stress of the rail and concrete slab were analyzed, and the analytical results were compared with the results of ANSYS, which proved the reliability of the analytical solution. Therefore, simplifying the slab ballastless track into infinite double-layer elastic beam is closer to the actual working conditions. The results can provide a reliable basis for the theoretical study of the ballastless track of high-speed railways and design reference for related projects

Oxygen Consumption and Lethal Dissolved Oxygen Level of Hybrids of Siniperca chuatsi♀ × S. scherzeri♂

Oxygen consumption rate (OCR) and lethal dissolved oxygen levels (DO) of the hybrids (225.3 ± 4.6 g) of Siniperca chuatsi ♀ × S. scherzeri ♂, were determined after acclimating the fish to 15, 20, 26 and 30°C for 20 days. The same parameters were measured for hybrids with different body weight (146.8 ± 6.3 g, 234.3 ± 8.4 g, 273.9 ± 3.3 g, 327 ± 5.1 g) at 26 °C. OCR increased significantly (P <0.05) with increasing acclimation temperature between 20-26°C, and decreased with increasing body weight. Final preferred temperature estimated from the Q10 was between 26-30°C. The lethal DO concentration for the hybrids at 30°C was significantly higher (P <0.05) than at other temperatures. OCR over the daily cycle under natural lighting conditions was also determined at 26°C. It showed a circadian rhythm with the lowest point at 0830 and peak rates at 1430. Results show that the hybrid has a higher stress tolerance and higher stocking density than the female parent S. chuatsi and indicate their culture potential in subtropical freshwater regions

Gut microbiota mediated the therapeutic efficiency of Simiao decoction in the treatment of gout arthritis mice

Abstract Background Gut microbiota plays a significant role in the development and treatment of gouty arthritis. Simiao decoction has been shown to alleviate gouty arthritis by inhibiting inflammation, regulating NLRP3 inflammasome, and altering gut microbiota. However, there is no evidence to prove whether gut microbiota directly mediates the therapeutic efficiency of Simiao decoction in treating gout arthritis. Methods In this study, fecal microbiota transplantation (FMT) was used to transfer the gut microbiota of gout arthritis mice treated with Simiao decoction or allopurinol to blank gout arthritis mice, in order to investigate whether FMT had therapeutic effects on gout arthritis. Results Both Simiao decoction and allopurinol effectively reduced the levels of serum uric acid, liver XOD activity, foot thickness, serum IL-1β, and G-CSF in gout arthritis mice. However, Simiao decoction also had additional benefits, including raising the pain threshold, reducing serum TNF-α and IL-6, alleviating gut inflammation, and repairing intestinal pathology, which were not observed with allopurinol treatment. Moreover, Simiao decoction had a greater impact on gut microbiota than allopurinol, as it was able to restore the abundance of phylum Proteobacteria and genus Helicobacter. After transplantation into gout arthritis mice, gut microbiota altered by Simiao decoction exhibited similar therapeutic effects to those of Simiao decoction, but gut microbiota altered by allopurinol showed no therapeutic effect. Conclusions These findings demonstrates that Simiao decoction can alleviate gout arthritis symptoms by regulating gut microbiota

Multi-omics reveals the role of ENO1 in bladder cancer and constructs an epithelial-related prognostic model to predict prognosis and efficacy

Abstract α-Enolase (ENO1) is a crucial molecular target for tumor therapy and has emerged as a research hotspot in recent decades. Here, we aimed to explore the role of ENO1 in bladder cancer (BLCA) and then construct a signature to predict the prognosis and treatment response of BLCA. Firstly, we found ENO1 was highly expressed in BLCA tissues, as verified by IHC, and was associated with poor prognosis. The analysis of the tumor immune microenvironment by bulk RNA-seq and scRNA-seq showed that ENO1 was associated with CD8+ T-cell exhaustion. Additionally, the results in vitro showed that ENO1 could promote the proliferation and invasion of BLCA cells. Then, the analysis of epithelial cells (ECs) revealed that ENO1 might promote BLCA progression by metabolism, the cell cycle and some carcinogenic pathways. A total of 249 hub genes were obtained from differentially expressed genes between ENO1-related ECs, and we used LASSO analysis to construct a novel signature that not only accurately predicted the prognosis of BLCA patients but also predicted the response to treatment for BLCA. Finally, we constructed a nomogram to better guide clinical application. In conclusion, through multi-omics analysis, we found that ENO1 was overexpressed in bladder cancer and associated with poor prognosis, CD8+ T-cell exhaustion and epithelial heterogeneity. Moreover, the prognosis and treatment of patients can be well predicted by constructing an epithelial-related prognostic signature

Anal. Methods

Synthesis of molecularly imprinted nanoparticles for tripterine with good selectivity and high adsorption capacity by precipitation polymerization is presented for the first time, in which tripterine, methacrylic acid and ethylene glycol dimethacrylate were used as a template molecule, functional monomer and cross-linker, respectively. The preparation conditions of molecularly imprinted nanoparticles were optimized, and the optimal molar ratio of template to functional monomer to cross-linker was 1 : 3 : 3. And non-imprinted polymers (NIPs) for control experiments were also prepared. The nanoparticles were characterized using a scanning electron microscope, laser particle size analyzer and BET, respectively. The results indicated that the imprinted nanoparticles were spherical in shape and the size was relatively uniform. Selectivity analysis suggested that the obtained imprinted nanoparticles could specifically recognize tripterine. In addition, adsorption kinetics and adsorption isotherm of the imprinted nanoparticles were utilized to study the binding characteristics of the imprinted nanoparticles. The results revealed that the imprinted nanoparticles had high adsorption capacity and the maximum adsorption capacity of tripterine on the imprinted particles was up to 145.97 mg g(-1). In potential application research, this adsorbent was satisfactorily employed as a solid-phase extraction sorbent to extract TTR in urine samples.Synthesis of molecularly imprinted nanoparticles for tripterine with good selectivity and high adsorption capacity by precipitation polymerization is presented for the first time, in which tripterine, methacrylic acid and ethylene glycol dimethacrylate were used as a template molecule, functional monomer and cross-linker, respectively. The preparation conditions of molecularly imprinted nanoparticles were optimized, and the optimal molar ratio of template to functional monomer to cross-linker was 1 : 3 : 3. And non-imprinted polymers (NIPs) for control experiments were also prepared. The nanoparticles were characterized using a scanning electron microscope, laser particle size analyzer and BET, respectively. The results indicated that the imprinted nanoparticles were spherical in shape and the size was relatively uniform. Selectivity analysis suggested that the obtained imprinted nanoparticles could specifically recognize tripterine. In addition, adsorption kinetics and adsorption isotherm of the imprinted nanoparticles were utilized to study the binding characteristics of the imprinted nanoparticles. The results revealed that the imprinted nanoparticles had high adsorption capacity and the maximum adsorption capacity of tripterine on the imprinted particles was up to 145.97 mg g(-1). In potential application research, this adsorbent was satisfactorily employed as a solid-phase extraction sorbent to extract TTR in urine samples

Precise absolute positioning for a single-frequency user

A new strategy to realize precise absolute positioning for a single-frequency user is presented. In the presented strategy, the receiver clock and ambiguities are removed using the satellite- and epoch-differenced (SDED) algorithm. As a further development of the SDED algorithm, a regional augmentation network is used to generate the SDED atmospheric delays at the user. The weakened mathematic property due to the epoch-differenced operation is improved by adding the generated atmospheric delays and applying the robust estimation. To test the new approach, the 24-h data at 5 Continuous Operation Reference Station (CORS) stations in Shanghai is processed. The results show a more than 96% success rate, defined as the case where three directions achieve the desired positioning accuracy of 10 cm, when the observation is longer than 20 min. The 20-min static results show that the new method can reach an accuracy of 3.42, 4.76 and 9.26 cm in the North, East and Up directions, respectively. An experiment was carried out to assess the kinematic positioning. The results show that the kinematic positioning accuracy is 4.11, 5.31 and 4.05 cm in the north-south, east-west and height directions, respectively

Taurine Attenuates Carcinogenicity in Ulcerative Colitis-Colorectal Cancer Mouse Model

Taurine (2-aminoethane-sulfonic acid) is a type of amino acids and has numerous physiological and therapeutic functions, including anti-inflammation. However, there are few studies on the anticancer action of taurine. Our previous studies have demonstrated that taurine exhibits an apoptosis-inducing effect on human nasopharyngeal carcinoma cells in vitro. In this study, we have investigated whether taurine has an anticancer effect, using azoxymethane (AOM)/sulfate sodium (DSS)- induced mouse model for colon carcinogenesis. All mice, except those in control group, received a single intraperitoneal injection of AOM and DSS in the drinking water for 7 days twice, with 1-week interval. After the first DSS treatment, mice were given distilled water (model group) or taurine in the drinking water (taurine group) ad libitum. No tumor was observed in the control group. Taurine significantly suppressed AOM+DSS-induced tumor formation. Histopathological examination revealed AOM/DSS treatment induced colon cancer in all mice (8/8, 100%), and taurine significantly inhibited the progression of colon cancer (4/9, 44.4%). Taurine significantly attenuated cell proliferation in cancer tissues detected by Ki-67 staining. Taurine significantly increased the levels of an apoptosis marker cleaved caspase-9 and tumor suppressor protein PTEN. This is the first study that demonstrated that taurine significantly reduced carcinogenicity in vivo using AOM/DSS-induced colon cancer mouse model