钾改性Mn/Ce0.65Zr0.35O2催化剂催化氧化甲苯

碱金属作为助剂,能够调变催化剂的电子和结构性能,从而改善催化剂的活性。本工作中,我们研究了碱金属K的添加对Mn Ox/Ce0.65Zr0.35O2催化剂氧化甲苯的性能影响。结果表明,掺杂碱金属K可以明显提高催化剂的催化活性;当K与Mn的摩尔比为0.2时,催化剂Mn/Ce0.65Zr0.35O2-K-0.2表现出最好的活性。在体积空速为12000 h-1时,其完全转化温度T90为242°C。同时采用X射线粉末衍射、紫外/可见拉曼、程序升温还原与吸脱附、光电子能谱及红外原位等表征技术研究K的添加对催化剂Mn Ox/Ce0.65Zr0.35O2性能影响。结果表明,适量K的添加可以提高催化剂的氧化还原性能,增加催化剂表面缺陷位并提高晶格氧的移动性,同时增加了催化剂表面活性氧物种浓度,从而提高催化剂催化氧化甲苯的能力。

Cytochrome b5 reductase 2 suppresses tumor formation in nasopharyngeal carcinoma by attenuating angiogenesis

Background:Cytochrome b5 reductase 2(CYB5R2) is a potential tumor suppressor that inhibits cell proliferation and motility in nasopharyngeal carcinoma(NPC).Inactivation of CYB5R2 is associated with lymph node metastasis in NPC.This study aimed to explore the mechanisms contributing to the anti-neoplastic effects of CYB5R2.Methods:Polymerase chain reaction(PCR) assays were used to analyze the transcription of 84 genes known to be involved in representative cancer pathways in the NPC cell line HONE1.NPC cell lines CNE2 and HONE1 were transiently transfected with CYB5R2,and data was validated by real-time PCR.A chick chorioallantoic membrane(CAM)embryo model was implanted with CYB5R2-expressing CNE2 and HONE1 cells to evaluate the effect of CYB5R2 on angiogenesis.An immunohistochemical assay of the CAM model was used to analyze the protein expression of vascular endothelial growth factor(VEGF).Results:In CYB5R2-transfected NPC cells,PCR assays revealed up-regulated mRNA levels of Fas cell surface death receptor(FAS),FBJ murine osteosarcoma viral oncogene homolog(FOS),phosphoinositide-3-kinase regulatory subunit 1(PIK3R1),integrin beta 3(ITGB3),metastasis suppressor 1(MTSSl),interferon beta 1(IFNB1),and cyclin-dependent kinase inhibitor 2A(CDKN2A) and down-regulated levels of integrin beta 5(ITGB5),insulin-like growth factor 1(IGF1),TEK tyrosine kinase(TEK),transforming growth factor beta receptor 1(TGFBRl),and VEGF.The angiogenesis in the CAM model implanted with CYB5R2-transfected NPC cells was inhibited.Down-regulation of VEGF by CYB5R2 in NPC cells was confirmed by immunohistochemical staining in the CAM model.Conclusion:CYB5R2 up-regulates the expression of genes that negatively modulate angiogenesis in NPC cells and down-regulates the expression of VEGF to reduce angiogenesis,thereby suppressing tumor formation.

YB-1 downregulation attenuates UQCRC1 protein expression level in H9C2 cells and decreases the mitochondrial membrane potential

UQCRC1 is one of the 10 mitochondrial complex III subunits,this protein has a role in energy metabolism,myocardial protection,and neurological diseases.The upstream mechanism of the UQCRC1 protective effect on cardiomyocytes is currently unavailable.In order to explore the upstream molecules of UQCRC1 and elucidate the protective mechanism of UQCRC1 on cardiomyocytes in more detail,we focused on the nuclease-sensitive elementbinding protein 1(YB-1).We hypothesized YB-1 acts as an upstream regulatory molecule of UQCRC1.This study found that YB-1 RNAi significantly reduces the expression of the UQCRC1 protein level(p<0.05)and obviously decreases the mitochondrial membrane potential(p<0.05),and that YB-1 interacts with UQCRC1 protein in vivo,but YB-1 RNAi has little effect on the UQCRC1 gene transcription.

Tissue-specific Expression of Acetolactate Synthase (ALS), Male Sterility-inducing Effect of Tribenuron-methyl and Its Effect on ALS Activity in Brassica napus L.

[Objectives]This study was conducted to provide a basis for the rapid identification of the drug spraying effect in early stage and the molecular mechanism of chemical hybridizing in Brassica napus L.[Methods]Quantitative RT-PCR analysis showed that ALS was constitutively expressed in various tissues of 096030,including flower buds,four floral organs (calyxes,petals,stamens and pistils),roots,stems and leaves.ALS was prominently expressed in leaves and was expressed weakly in the petals and stamens.The male sterility-inducing effects of tribenuron-methyl on such two Brassica napus L.varieties as Ningyou18 and 096030 were investigated.[Results]Plants were twice sprayed with 0.2 μg/ml tribenuron-methyl on leaves.The results showed that 8-10 ml of tribenuron- methyl was applied per plant for the first time at bolting stage with 1-2 mm flower buds on 15-20 cm inflorescence,and the second spray was performed with 8-10 ml of tribenuron-methyl per plant 10 d later.The results showed that the percentage of the full sterile plants reached 100%,which lasted for the whole flowering period,and the relative seed setting rate was only about 4%.Thus,this method could fullfill the requirement of hybrid seed production in field.The in-vivo enzyme activity of acetolactate synthase (ALS) was assayed using 2 mm buds collected 3 d after spray.The results showed that 0.2 μg/ml tribenuron-methyl inhibited ALS activity.The ALS activity of Ningyou 18 (CK) and Ningyou 18 (0.2 μg/ml) was 3.20 and 1.30 μmol/(mg·h),respectively,and the ALS activity of 096030 (CK) and 096030 (0.2 μg/ml) was 3.37 and 1.25 μmol/(mg·h),respectively.The relative enzyme activity of ALS in Ningyou18 and 096030 was 40.63% and 37.23%,respectively,both of which decreased significantly.[Conclusions]These results showed that the change of ALS activity may be used as an index for quickly identifying and predicting the chemical hybridizing effect of tribenuron-methyl.

Cloning of CRABS CLAW Gene from Brassica napus and Construction of Its RNA Interference Expression Vector

CRABS ClAW （CRC） is a member of the YABBYA transcription factor gene family that plays an important role in floral organ development of plants. This study aimed to further investigate the regulatory function of CRC transcription factor in the development of floral organs of rape （Brassica napus L. ）. A 580 bp fragment of CRC gene was cloned by RT-PCR from total RNA of buds of rape cultivar Ningyou No. 10 to construct an inverted repeated expression cassette of CRC gene using intermediate vector pHturieane. Firstly, CRC gene fragment was positively inserted into the 5＇ end of a spliceable intron and negatively inserted into the 3＇ end of the intron. Subsequently, CaMV35S promoter sequence and inverted repeated expression cassette of CRC gene were transferred into pUC18 multiple clone site of binary expression vector pCAMBIAI1390. The constructed interference expression vector was named pA6-CRCi, which was further confirmed by restriction enzyme digestion and sequencing.

Indoor Propagation of Transgenic Glyphosate-tolerant Rapeseed (Brassica napus L.) and Transfer Breeding for Herbicide Tolerance

[Objectives] This study was conducted to investigate the possibility of screening for herbicide resistance in the early stage of rapes growth. [Methods] Eight treatments were set for a herbicide concentration experiment. [Results] Rape sprouts were highly sensitive to the herbicide glyphosate, and even a very low concentration of glyphosate solution(187 mg/L) was sufficient to kill most of the rape seedlings, while the genetically modified herbicide-tolerant rape could tolerate higher concentrations of the herbicide. Low concentrations of glyphosate could be used for screening at the sprout stage, and the results of herbicide-tolerance screening were consistent with PCR testing. [Conclusions] This study lays a technical and material foundation for accelerating the cultivation of new herbicide-resistant rape varieties suitable for rapeseed production areas in the lower reaches of the Yangtze River.

Liposome-encapsulated dimethyl curcumin inhibits over-activation of rat lymphocyte to relieve collagen-induced arthritis by regulating intracellular proteolysis and PCNA/p21/caspase-3 pathway

Dimethyl curcumin,a synthetic derivative of curcumin,has good anti-cancer,anti-arthritis and anti-inflammatory properties,but underline mechanism was unclear.Activation,differentiation,proliferation and apoptosis of lymphocytes have important functions during arthritis development and immune homeostasis.Over-activation of lymphocyte causes inflammatory cytokines storm,leading to an immune imbalance and tissue damages.The aim of this study was to investigate the anti-inflammation mechanism of liposome encapsulated dimethyl curcumin(Lipo-DiMC)on over-activated rat spleen lymphocytes.In this study,Lipo-DiMC was produced to increase the solubility;the primary rat spleen lymphocytes were extracted and the Concanavalin A induced cell activation model was established to study the cellular responses to Lipo-DiMC treatment in-vitro.The results showed that Lipo-DiMC suppressed Concanavalin A-induced cell proliferation,inhibited cells entering G2/M phase,and reduced the ratio of necrosis/apoptosis by manipulating intracellular p53/p21/PCNA/JNK-1 pathways.Furthermore,Lipo-DiMC increased the accumulations of intracellular matrix metalloproteinase-9 and reduced matrix metalloproteinase-9 secretion of rat spleen lymphocytes.Also,Lipo-DiMC increased intracellular caspase-3 expression and reduced Cat-C activity in activated rat spleen lymphocytes,involving in intracellular proteolysis.Our findings suggest that dimethyl curcumin effectively alleviates Concanavalin A induced over-activation of rat spleen lymphocytes,thereby inhibiting inflammatory cytokines storm and restoring cell homeostasis.

Aqueous extract of Taxus Chinensis (Pilger) Rehd inhibits lung carcinoma A549 cells through the epidermal growth factor receptor/mitogen-activated protein kinase pathway in vitro and in vivo

OBJECTIVE： To explore the anticancer mechanism of aqueous extract of Taxus Chinensis （Pilger） Rehd （AETC）. METHODS： The serum pharmacological method was used to avoid interference from administration of the crude medicinal herbs. Eight purebred NewZealand rabbits were used for preparation of serum containing various concentrations of AETC. For- ty-eight Balb/c-nu mice were used for in vivo experi- ments. The effects of serum containing AETC on the proliferation of A549 cells and expression levels of the epidermal growth factor receptor/mito- gen-activated protein kinase （EGFR/MAPK） path- way-related proteins in vitro were investigated. Ad- ditionally, the effects on the growth of A549 xeno- grafts in nude mice, and expression levels of the EG- FR/MAPK pathway-related proteins in the xeno- grafts, were investigated. RESULTS： 3-（4,5-dimethylthiazol-2-yl）-2,5-diphenyl- tetrazolium bromide （MTT） assay revealed that the serum containing AETC significantly decreased the viability of A549 cells in a dose-dependent manner. Western blot showed that the serum containing various concentrations of AETC strongly reduced the levels of phospho-Jun N-terminal kinase （p-JNK） and phospho-extracellular signal-regulated kinasel/2 （ERK1/2） while it increased the level of p-p38. However, no significant effects on the ex- pression levels of JNK, ERK1/2, and p38 MAPK were found. In addition, an anticancer effect from AETC was observed in vivo in the Balb/c-nu mice bearing A549 xenografts.CONCLUSION： AETC has significant effects on the growth of A549 xenografts and on the activity of the EGFR/MAPK pathway. Therefore, AETC may be beneficial in lung carcinoma treatment.

Even-odd-dependent optical transitions of zigzag monolayer black phosphorus nanoribbons

We analytically study the electronic structure and optical properties of zigzag-edged phosphorene nanoribbons(ZPNRs) using the tight-binding Hamiltonian and Kubo formula. By directly solving the discrete Schrodinger equation, we obtain the energy spectra and wavefunctions for N-ZPNR(where N is the number of transverse zigzag atomic chains) and classify the eigenstates according to the lattice symmetry. Then, we obtain the optical transition selection rule of ZPNRs on the basis of symmetry analysis and analytical expressions of optical transition matrix elements. Under incident light that is linearly polarized along the ribbon, we determine that the optical transition selection rule for N-ZPNR with even-or odd-N is qualitatively different. Specifically, for even-N ZPNRs, the inter-(intra-) band selection rule is ?n =odd(even) because the parity of the wavefunction corresponding to the n-th subband in the conduction(valence) band is(-1)~n[(-1)~((n+1))] owing to the presence of C(2x) symmetry. However, the optical transitions between any subbands are possible owing to the absence of C(2x) symmetry. Our results provide a further understanding on the electronic states and optical properties of ZPNRs, which are useful for explaining the optical experiment data on ZPNR samples.