Integrating Olefin Carboamination and Hofmann-Löffler-Freytag Reaction by Radical Deconstruction of Hydrazonyl N-N Bond.

As a type of elementary organic compounds containing N-N single bond, hydrazone involved chemical conversions are extremely extensive, but they are mainly limited to N2-retention and N2-removal modes. We report herein an unprecedented protocol for the realization of division utilization of the N2-moiety of hydrazone by a radical facilitated N-N bond deconstruction strategy. This new conversion mode enables the successful combination of alkene carboamination and Hofmann-Löffler-Freytag reaction by the reaction of N-homoallyl mesitylenesulfonyl hydrazones with ethyl difluoroiodoacetate under photocatalytic redox neutral conditions. Mechanism studies reveal that the reaction undergoes a radical relay involving addition, crucial remote imino-N migration and H-atom transfer. Consequently, a series of structurally significant ϵ-N-sulphonamide-α,α-difluoro-γ-amino acid esters are efficiently produced via continuous C-C bond and dual C-N bonds forging.

Pericytes protect rats and mice from sepsis-induced injuries by maintaining vascular reactivity and barrier function: implication of miRNAs and microvesicles.

BACKGROUND: Vascular hyporeactivity and leakage are key pathophysiologic features that produce multi-organ damage upon sepsis. We hypothesized that pericytes, a group of pluripotent cells that maintain vascular integrity and tension, are protective against sepsis via regulating vascular reactivity and permeability. METHODS: We conducted a series of in vivo experiments using wild-type (WT), platelet-derived growth factor receptor beta (PDGFR-ß)-Cre + mT/mG transgenic mice and Tie2-Cre + Cx43flox/flox mice to examine the relative contribution of pericytes in sepsis, either induced by cecal ligation and puncture (CLP) or lipopolysaccharide (LPS) challenge. In a separate set of experiments with Sprague-Dawley (SD) rats, pericytes were depleted using CP-673451, a selective PDGFR-ß inhibitor, at a dosage of 40 mg/(kg·d) for 7 consecutive days. Cultured pericytes, vascular endothelial cells (VECs) and vascular smooth muscle cells (VSMCs) were used for mechanistic investigations. The effects of pericytes and pericyte-derived microvesicles (PCMVs) and candidate miRNAs on vascular reactivity and barrier function were also examined. RESULTS: CLP and LPS induced severe injury/loss of pericytes, vascular hyporeactivity and leakage (P < 0.05). Transplantation with exogenous pericytes protected vascular reactivity and barrier function via microvessel colonization (P < 0.05). Cx43 knockout in either pericytes or VECs reduced pericyte colonization in microvessels (P < 0.05). Additionally, PCMVs transferred miR-145 and miR-132 to VSMCs and VECs, respectively, exerting a protective effect on vascular reactivity and barrier function after sepsis (P < 0.05). miR-145 primarily improved the contractile response of VSMCs by activating the sphingosine kinase 2 (Sphk2)/sphingosine-1-phosphate receptor (S1PR)1/phosphorylation of myosin light chain 20 pathway, whereas miR-132 effectively improved the barrier function of VECs by activating the Sphk2/S1PR2/zonula occludens-1 and vascular endothelial-cadherin pathways. CONCLUSIONS: Pericytes are protective against sepsis through regulating vascular reactivity and barrier function. Possible mechanisms include both direct colonization of microvasculature and secretion of PCMVs.

Heavy metal-contained wastewater in China: Discharge, management and treatment.

A large amount of heavy metal-contained wastewater (HMW) was discharged during Chinese industry development, which has caused many environmental problems. This study reviewed discharge, management and treatment of HMW in China through collecting and analyzing data from China's official statistical yearbook, standards, technical specifications, government reports, case reports, and research paper. Results showed that industry wastewater discharged by an amount of about 221.6 × 108 t (in 2012), where emission of heavy metals including Pb, Hg, Cd, Cr(VI), T-Cr was around 388.4 t (in 2012). Heavy metal emission with wastewater in east China and central south China was observed to be graver than that in other areas. However, control of heavy metals in Pb and Cd in northwest China was more difficult compared with other areas. In terms of management, China's government has issued many wastewater discharge standards, strict management policies for controlling HMW discharge in recent years, resulting in reduced HMW discharge. In addition, main HMW treatment technology in China was chemical precipitation, and other technologies such as membrane separation, adsorption, ion exchange, electrochemical and biological methods were also occasionally applied. In the future, chemical industries will be concentrated in northwest China, therefore control of HMW discharge should be paid much more attention in those areas. In addition, more effective and environment-friendly heavy metal removal and regeneration technologies should be developed, such as biomaterials adsorbent.

[Influence of Activated Sludge Surface Properties on Flocculating Settling and Effluent Suspend Solid].

In this paper, the influence of the surface properties of the activated sludge on flocculating settling and ESS was studied in seven different sewage treatment plants in Beijing, such as the sludge volume index (SVI), the protein/carbohydrate (P/C) ratio in extracellular polymeric substance, Zeta potential, two-dimensional fractal dimension(D2f). The relationships between the surface properties of the activated sludge and flocculation ability (FA) or effluent suspend solid(ESS) were also analyzed. The results showed that no obvious correlation was obtained between SVI and FA or ESS, but obvious negative correlation between the FA and ESS (R2=0.787) was observed. When the P/C increased from 1.28 to 25.34, the FA could increase from 0.19 to 0.73 correspondingly, but the ESS decreased from 14.89 mg·L-1 to 6.08 mg·L-1. This was because the amino acids in protein with positive charge could neutralize the negative charge on the surface of floc, the increase of protein ratio in EPS could decrease the absolute value of Zeta potential, which made a contribution to form more stable floc structure, and improved the ability of flocculation. Moreover, the Zeta potential had a positive correlation with FA but a negative correlation with ESS. The absolute value of Zeta potential decreased by 1 mV, FA increased by 0.059 and ESS decreased by 0.934 mg·L-1 correspondingly. In addition, there was an obvious index correlation (R2=0.935, P<0.01) between D2f and FA; While D2f increased from 1.10 to 1.45, FA could increase by 4.3 times and ESS decreased linearly (R2=0.868).

[Carbon/nitrogen Removal and Bacterial Community Structure Change in an A/O Activated Sludge System Under Different Dissolved Oxygen Conditions].

Carbon and nitrogen removal performance and microbial community structure under different dissolved oxygen (DO) conditions (3, 2, 1 and 0. 5 mg . L -1) in an anoxic/oxic (A/O) system were investigated. The results showed that the A/O activated sludge system still had an excellent performance in removing carbon and nutrient under low DO condition (0. 5 mg . L-1). The removal rates of chemical oxygen demand (COD), ammonia (NH4+ -N) and total nitrogen (TN) were 89. 7%, 98. 3% and 88. 0% respectively. The PCR-DGGE analysis showed that the bacterial community structure changed greatly under different DO conditions. However, there was still a high bacterial diversity even at low DO level, which ensured the functional stability of the A/O system. On the basis of the results of the phylogenetic tree, bacterial communities were observed to be very abundant, and Proteobacteria was identified as the dominant bacteria.

[Immunosensor for rapid detection of 1,3-dinitrobenzene].

An immunosensor for the rapid detection of 1,3-dinitrobenzene was developed based on an evanescent wave all-fiber biosensing platform with the detection limits of 0.054 mg x L(-1), and the detection cycle was less than 10 min. Hapten-carrier conjugates NB-OVA were synthesized by mixing 4-nitrohippuric acid and OVA activated by EDC, and then the conjugates were immobilized onto the silane layer on the probe with a heterobifunctional crosslinker. The probe modified had good robustness and regeneration performance, which allowed the performance of more than 100 assay cycles without significant loss of reactivity. Several water samples of different origins were measured with less than 4.5% -10.0% deviation of the detection and the recovery rate of 1,3-dinitrobenzene was between 80% and 120%, which proved the system's precision and accuracy and negligible matrix effects. This immunosensor shows great potential in rapid detection of 1,3-dinitrobenzene in practical waters.

[Half-nitrosofication of dewatering liquid of digested sludge with high ammonia].

The affecting factors and controlling methods of how realizing and maintaining half-nitrosofication of dewatering liquid of digested sludge were investigated in an A/O process. The experimental results showed that the nitritation was obtained in 29 d under bulk liquid temperature of 9-20 degrees C, average DO of 5.4 mg/L, SRT of about 30 d and influent ammonia loading rate of 0.64 kg/(m3 x d). The nitritation with 70% nitrite accumulation efficiency was maintained during 65 d when average FA concentration in A/O reactor was more than 4 mg/L. Furthermore, the half-nitrosofication with effluent ammonia and nitrite ratio of 1:1.32 was obtained. When the ammonia loading rate reduced to 0.19 kg/(m3 x d) (FA < 1 mg/L), the nitritation disappeared, and the high FA as a main factor of maintaining half-nitrosofication was proved again with FISH under the condition of different FA. TN removal concentration was about 91 mg/L under influent COD of 282 mg/L and raw C/N ratio of 0.85 in the A/O system, which due to nitritation saving much carbon sources. The study showed that the half-nitrosofication of the dewatering liquid was obtained and stably maintained when FA was more than 4 mg/L in the A/O reactor by dynamic controlling influent ammonia loading rate and pH value in the system under middle or low temperature, high DO, long SRT.

[Start up and maintain of nitritation by the inhibition of FA and FNA].

In order to treat the digested sludge dewatering liquor bypass and reduce influent ALR of wastewater treatment plant, the startup and maintenance of nitritation was investigated in an A/O reactor. NOB activity was inhibited and nitritation was stated up successfully by increasing the influent ALR (in N, the same below) step by step from 0.23 kg/(m3 x d) to 0.78 kg/(m3 x d), in spite of normal temperature, long SRT and high DO concentration. Due to the deficiency of alkalinity in influent, nitritation could be maintained steadily by the associated inhibition of free ammonia (FA) and free nitrous acid (FNA). The nitrite accumulation ratio always kept at above 90% during the period of maintaining nitritation for 30 days, and correspondingly the average concentration of DO was higher than 2 mg/L. The nitrite accumulation ratio did not decline even if the average DO concentration increased to 4.8 mg/L, which demonstrated that high DO could not destroy the nitritation built by the associated inhibition of FA and FNA. The concentration of FNA at the last chambers was increased by reducing the influent ALR in order to enhance the inhibition of FNA. The nitritation was still maintained for two months although the inhibition of FA was weakened. But the nitritation was destroyed completely in 3 days after the inhibition of FNA was eliminated, which showed the inhibition of FNA to NOB was very critical to maintain steadily nitritation.

[Partial nitrification of digested sludge liquor with low C/N and high-concentration ammonia].

The experimental system consisted of anoxic filter and aerobic suspended carrier biofilm reactor. The partial nitrification was achieved and maintained stably in the aerobic reactor under normal temperature (15-29 degrees C) and high DO (6-9 mg/L). The nitritation with 70%-80% nitrite accumulation efficiency was obtained when FA concentration was in the range of 1.0-10.3 mg/L by controlling influent ammonia loading rate (ALR), ratio of alkalinity and ammonia and HRT in the aerobic reactor. The effluent nitrite/ammonia ratio was about 1.25 when the average influent ammonia, influent ALR and influent ratio of alkalinity and ammonia were 315.80 mg/L, 0.43 kg/(m3 x d) and 5.25, respectively. So the effluent of partial nitrification process provided the influent substrate demand for the following ANAMMOX process. The integrative analysis indicated that the proper FA concentration was the main factor achieving the partial nitrification. The study developed a novel partial nitrification technology adapt to water characteristics of digested sludge liquor.

Identification of genes differentially expressed in human hepatocellular carcinoma by a modified suppression subtractive hybridization method.

To identify differentially expressed genes in human HCC in China, we applied a modified SSH method for cDNA subtraction. Such modification has made the method more effective for subtraction. We have obtained 36 and 24 differentially expressed cDNA fragments after modified SSH from 4 paired samples of human HCC and non-HCC tissues, respectively. Reverse Northern blotting analysis was performed to further identify the genes differentially expressed in the HCC and non-HCC tissue samples. There were 25 genes really overexpressed in HCC, and their corresponding encoding molecules may reflect the events of cell accelerated metabolism, proliferation, angiogenesis, anti-apoptosis, tumorigenesis (TLH107, TFH9) and the potential for metastasis. Of the 25 genes overexpressed in HCC, 5 were novel and their full-length cDNAs were cloned. These 5 novel genes are functionally associated with the occurrence and development of HCC according to the Database analysis. In the paired non-HCC tissues, there were 15 genes lowly or not expressed in HCC, and their encoding proteins function as tumor suppressors (TFA3, TFA11), acute-phase reactive proteins, and the blood plasma proteins that are mainly or exclusively synthesized in the liver. The distinct profiles of the differentially expressed genes in HCC and the paired non-HCC tissues have partially reflected the genetic alterations during HCC tumorigenesis. The novel HCC-specific gene TLH6 and the CT antigen encoding gene TLH107 may have diagnostic and therapeutic potentials in HCC and/or other solid cancers.