Dinuclear zinc-catalyzed enantioselective formal [3 + 2] cycloaddition of N-2,2,2-trifluoroethylisatin ketimines with low reactivity aurone derivatives.

Highly enantioselective formal [3 + 2] cycloaddition of N-2,2,2-trifluoroethylisatin ketimines with aurone derivatives of low reactivity using chiral dinuclear zinc catalysts has been developed via a Brønsted base and Lewis acid cooperative activation model. These transformations involving a domino Michael/Mannich reaction sequence led to efficient construction of a range of chiral spiro[benzofuran-pyrrolidine] scaffolds bearing three biologically relevant heterocyclic moieties and two adjacent spiro quaternary stereocenters in high yields (up to 95%) and with good enantioselectivities (up to 99% ee).

Brønsted Base and Lewis Acid Cooperatively Catalyzed Asymmetric exo'-Selective [3 + 2] Cycloaddition of Trifluoromethylated Azomethine Ylides and Methyleneindolinones.

A Brønsted base and Lewis acid cooperatively catalyzed 1,3-dipolar cycloaddition is reported through chiral dinuclear zinc catalysts. An asymmetric exo'-selective [3 + 2] cycloaddition of CF3-containing N-unprotected isatin-derived azomethine ylides is realized. In the presence of 10 mol % of catalyst, azomethine ylides react efficiently with methyleneindolinones, giving a series of trifluoromethyl-substituted 2,3-pyrrolidinyl dispirooxindoles with highly enantio- (up to 99% ee) and exo'-selectivity (>20:1 dr). Up to four contiguous stereogenic centers, including two adjacent spiro quaternary stereocenters, are constructed in one step.

Catalytic Asymmetric Synthesis of Tetrahydrofuran Spirooxindoles via a Dinuclear Zinc Catalyst.

An asymmetric Michael/hemiketalization and Fridel-Crafts reaction has been reported through a one-pot reaction. A number of structurally novel tetrahydrofuran spirooxindoles are synthesized in the presence of a 10 mol % dinuclear zinc catalyst with diastereomer ratios (dr) of 3:1-13:1 and an enantiomeric excess (ee) of 75-99%. The reaction can be performed on a gram scale without impacting its efficiency. The absolute configuration of products is confirmed by X-ray single crystal structure analysis, and a possible mechanism is proposed.

Impact of UGT2B7 and ABCC2 genetic polymorphisms on mycophenolic acid metabolism in Chinese renal transplant recipients.

AIM: To evaluate genetic variants affecting mycophenolic acid (MPA) metabolism in Chinese renal transplant recipients. METHODS: Total 11 SNPs of UGT1A9, UGT1A8, UGT2B7, ABCC2, ABCG2 and SLCO1B3 were genotyped in 408 Chinese renal transplant recipients. Associations between SNPs and MPA concentration/dose ratio (C0/D) were analyzed using different genetic models. Multivariate linear regression was used to analyze associations between log (C0/D) and clinical factors. Results: After adjustment by clinical factors, UGT2B7 rs7662029 was associated with log (C0/D) using a dominant (p = 0.041) and an additive (p = 0.038) model, ABCC2 rs717620 was associated with log (C0/D) using a recessive model (p = 0.019). Using additive model, SNP-SNP interactions were identified (p = 0.002) between ABCC2 rs717620 and UGT1A9 rs2741049, with interactions (p = 0.002) between ABCC2 rs717620 and UGT1A8 rs1042597. Age, albumin and serum creatinine were associated with log (C0/D). CONCLUSION: rs7662029 and rs717620 may affect MPA pharmacokinetics. SNP-SNP interactions and clinical factors may have significant effects on MPA metabolism.

Characterization of oligotrophic AnAOB culture: morphological, physiological, and ecological features.

Anaerobic ammonium oxidation (anammox) process is regarded as a promising nitrogen removal technology to treat ammonium wastewaters in a wide concentration range. Oligotrophic anaerobic ammonia oxidation bacteria (O-AnAOB) culture has been successfully achieved from a new anammox system to treat superlow ammonium concentration wastewaters. In this work, the O-AnAOB culture was compared with the eutrophic AnAOB (E-AnAOB) culture to reveal its physiological, morphological, and ecological features. Results showed that the specific anammox activity (SAA) of O-AnAOB culture was 0.07 kgN/(kgVSS·d) with the nitrogen removal rate (NRR) of 0.20 kgN/ (m3 d) in the reactor, while the SAA of E-AnAOB culture was 2.11 kgN/(kgVSS·d) with the NRR of 11.10 kgN/(m3 d). The hzs gene transcription levels (hzs-mRNA) of O-AnAOB and E-AnAOB cultures were 1.32 × 109 copies/gVSS and 1.51 × 1010 copies/gVSS, respectively. Morphologically, the O-AnAOB culture took on the unique brown color rather than the typical red color of E-AnAOB. The O-AnAOB cells lived in a disperse pattern in the culture. The cells were seriously deformed with deep craters on the cell wall. The size of anammoxsome and paryphoplasm compartments inside the O-AnAOB cells was smaller than that inside the E-AnAOB cells. Ecologically, the O-AnAOB culture had special microbial community with a higher bacterial diversity than the E-AnAOB. The most dominant genera in O-AnAOB were Anaerolineaceae (33.7%, fermentative bacteria), Candidatus Kuenenia (17.4%, anammox bacteria), and Nitrospira (7.3%, nitrite oxidizing bacteria). This study provided an insight into the new anammox process for deep nitrogen removal from wastewaters.

[Odor Emission Characteristics and Pollution Evaluation from Typical Household Rubbish Disposal Facilities].

In order to study the characteristics of odors from typical household rubbish disposal facilities, samples were taken from pretreatment workshops of the landfill process, incineration process, and composting process in Beijing, and cold enrichment-GC/MS was used to determine the odor component qualitatively and quantitatively. Results indicated that six categories were detected in all samples: aromatic hydrocarbons, sulfides, halides, olefins, alkanes, and oxygen containing organic substances. In the pretreatment workshop of the landfill process, 50 kinds of chemicals were detected, the total odor concentration was 100.069 mg·m-3, the theoretical odor concentration was 350.611, and the comprehensive odor index was 25.448. In the pretreatment workshop of the incineration process, 55 kinds of chemicals were detected, the total odor concentration was 36.052 mg·m-3, the theoretical odor concentration was 141.434, and the comprehensive odor index was 21.506. In the pretreatment workshop of the composting process, 34 kinds of chemicals were detected, the total odor concentration was 25.382 mg·m-3, the theoretical odor concentration was 27.547, and the comprehensive odor index was 14.401. Combined with the threshold of diluted multiples, the particular pollutants of the pretreatment workshop of the landfill process were dimethyl disulfide, butyl acetate, p-diethylbenzene, and ethanol. Similarly, the particular pollutants of the pretreatment workshop of the incineration process were methanethiol, dimethyl disulfide, ethanol, and limonene. The particular pollutants of the pretreatment workshop of the composting process were ethanol, dimethyl disulfide, butyl acetate, and limonene.

[Development of Self-assembled Dumbbell-like Fe3O4 Micro/nanomaterial for Application in Thermocatalytic Degradation of Polybrominated Biphenyls].

Polybrominated biphenyls (PBBs) are a group of new persistent organic pollutants, which have high toxicity and long-term bioaccumulation, and cause potential risks to human beings and aquatic ecosystem. Self-assembled dumbbell-like Fe3O4 was synthesized via ethylene-glycol mediated method to degrade PBBs, using BB209 as a model compound. The results showed that the growth process of dumbbell-like Fe3O4 precursor had two stages involving a fast nucleation of amorphous primary particles followed by a slow aggregation and crystallization of primary particles. Dumbbell-like Fe3O4 showed high activity for degradation of BB209 at the reaction time of 30 min with the degradation efficiency of nearly 100% at 300 degrees C. A whole series of nonabromobiphenyl to monobromobiphenyl and biphenyls were detected as the degradation products of BB209 by dumbbell-like Fe3O4, indicating the occurrence of successive hydrodebromination reaction. Furthermore, the amounts of three NoBB isomers followed the order of BB207 > BB208 > BB206, indicating that the reactivity of C--Br of BB209 was in order of meta- > para- > ortho-positions.

[Polymorphism analysis of 20 autosomal short-tandem repeat loci in southern Chinese Han population].

OBJECTIVE: To evaluate the value of PowerPlex®21 System (Promega) and study the genetic polymorphism of its 20 short-tandem repeat (STR) loci in southern Chinese Han population. METHODS: We conducted genotyping experiments using PowerPlex®21 System on 20 autosomal STR loci (D3S1358, D1S1656, D6S1043, D13S317, Penta E, D16S539, D18S51, D2S1338, CSF1PO, Penta D, TH01, vWA, D21S11, D7S820, D5S818, TPOX, D8S1179, D12S391, D19S433 and FGA) in 2367 unrelated Chinese Han individuals living in South China. The allele frequencies and parameters commonly used in forensic science were statistically analyzed in these individuals and compared with the reported data of other populations. RESULTS: The PowerPlex®21 System had a power of discrimination (PD) ranging from 0.7839 to 0.9852 and a power of exclusion (PE) ranging from 0.2974 to 0.8099 for the 20 loci. No significant deviation from Hardy-Weinberg expectations was found for all the loci except for D5S818. This southern Chinese Han population had significant differences in the allele frequencies from 8 ethnic groups reported in China, and showed significant differences at 8 to 20 STR foci from 5 foreign populations. The allele frequency at the locus D1S1656 in this southern Chinese Han population differed significantly from those in the 5 foreign populations and from 3 reported Han populations in Beijing, Zhejiang Province and Fujian Province of China. The neighbor-joining phylogenetictree showed clustering of all the Asian populations in one branch, while the northern Italian and Argentina populations clustered in a separate branch. This southern Chinese Han population had the nearest affinity with the Yi ethnic population in Yunnan Province of China. CONCLUSION: The 20 STR loci are highly polymorphic in this southern Chinese Han population, suggesting the value of this set of STR loci in forensic personal identification, paternity testing and anthropological study.

Effect of autologous platelet-rich plasma in combination with bovine porous bone mineral and bio-guide membrane on bone regeneration in mandible bicortical bony defects.

OBJECTIVE: Growth factors contained in platelet-rich plasma (PRP) can induce osteoblast differentiation in certain studies, whereas in others, osteogenesis of PRP on mandible bone defects has not been proved clinically. The aim of the study was to investigate the effect of autologous PRP on the osteogenic potential of combining bovine porous bone mineral (BPBM) and bio-guide membrane (BGM) in promoting mandible bicortical bony defects in rabbits. METHODS: One circular mandible bicortical bony defects were created in each of 54 rabbits, which were divided into 3 groups: group 1: 18 of the defects were left unfilled as a negative control; group 2: 18 of the defects were grafted with autologous PRP and BPBM/BGM; group 3: 18 of the defects were grafted with BPBM/BGM without PRP. Animals were killed at 4, 8, and 12 weeks after operation. Harvested tissue and specimens were evaluated histologically and radiographically, and metabolized observation was performed. Histological parameters associated with osteoblast activities, bone trabecula, neovascularization, newly formed mineralized bone, rudimental grafts and connective tissue formation were measured. Densities of the bones at 4, 8, and 12 weeks were studied by radiographic. The bone defect closure ratio was measured at 12 weeks. The bone metabolized parameter alkaline phosphatase was also measured and compared between 4, 8, and 12 weeks. RESULTS: The platelet concentration of PRP is 4.19- to 4.43-fold to that of the whole blood. Histological analysis showed new bone formation at all therapeutic sites including BPBM/BGM grafts with or without PRP. A statistically significant difference in new bone formation between group PRP/BPBM/BGM and group BPBM/BGM was observed. Untreated defects of group control showed the less bone regeneration. There was significant difference of bone density between group PRP/BPBM/BGM and control, and group BPBM/BGM and control, at 4, 8, and 12 weeks postoperative. There were more bone defects filling, and the grafts were absorbed at 12 weeks of group PRP/BPBM/BGM compared with group BPBM/BGM. Defects treated with PRP/BPBM/BGM demonstrated significantly increased activity of osteoblasts, enhanced amount of mitochondria and rough endoplasmic reticulum in osteoblasts, and increased concentration of alkaline phosphatase at 4, 8, and 12 weeks compared with those treated with BPBM/BGM and control group. Complete closure ratio of bone defects treated with PRP/BPBM/BGM (50%) was significantly increased compared with that treated with BPBM/BGM (16.6%). CONCLUSIONS: The study suggested that PRP combination of BPBM and BGM had significant therapeutic effects on mandible bicortical bony defects of rabbits. The effects are associated with the high concentration of platelet in PRP and the porous configuration of BPBM. Although we cannot reveal the detailed statistical relationship of PRP on promoting BPBM/GBM osteoinductive effects, PRP demonstrated superior results of bone regeneration.

[Effects of extraneous inorganic nitrogen forms on the dynamics of soil amino sugars].

Substrate availability affects microbial growth, whereas extraneous nitrogen forms can significantly affect microbial metabolic processes. As for soil amino sugars, the stable residues in microbial cell wall, their synthesis, decomposition and turnover are closely related to the availability of extraneous carbon and nitrogen. Using isotope tracing technique to study soil amino sugars can further understand the substrate utilization profiles by soil microorganisms. In this study, two incubation tests were conducted, with glucose plus 15N-labelled NH4+ or NO3- as the substrates, respectively. The 15N enrichment in each kind of soil amino sugars was identified by gas chromatography/ mass spectrometry (GC/MS) to trace the dynamics of soil 15N-labelled and native amino sugars. During the incubation, the content of soil 15N-labelled amino sugars increased significantly, and the transformation rate from NH4+ to amino sugars was significantly higher than that from NO3-, suggesting the preferred utilization of NH4+ than NO3- by soil microorganisms. Significant changes in the amounts of soil unlabelled amino sugars were observed. The amount of unlabelled glucosamine increased with NH4+ addition, but decreased gradually with NO3- addition. The content of unlabelled muramic acid decreased gradually, especially with NO3- addition. Either the increase or the decrease of galactosamine did not exceed 20% to the original value. These compound-specific changes showed that the heterogeneous microbial residues played different roles on the turnover and stabilization of nitrogen in soil matrix. Fungal cell wall residues were easily accumulated in soil matrix, which benefited the stabilization of soil organic matter, while bacterial cell wall residues were easily degraded, playing an important role in the turnover of soil organic matter.

Preparation, characterization and catalytic properties of Pd-Fe-zeolite and Pd-Ce-zeolite composite catalysts.

Highly effective composite catalysts for removal of CO by catalytic oxidation have been designed through constructing active centers on the support of zeolite. Performances of the derived Pd-Fe-zeolite and Pd-Ce-zeolite composite catalysts for CO removal under different heterogeneous conditions were studied. The results indicate that the two kinds of promoted catalysts, including special chemical states of Pd and surface active oxygen, show high catalytic activities not only for the low temperature oxidation of CO, but also for CO electro-oxidation. The typical light-off temperatures of Pd-Fe-zeolite and Pd-Ce-zeolite for low temperature CO oxidation are 270 and 273 K. Their characteristic peak potentials for CO electro-oxidation are both around 0.70 V. The promotional effects are associated with the special interaction among Pd, modifier and zeolite, which can be firmly supported by the detailed characterizations using XRD, BET, XPS, TPD and TPR.