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31.
PM2.5和PM10已成为我国大部分城市空气的首要污染物.本文通过分析南昌市2013—2015年的空气PM2.5和PM10质量浓度、气象因素、交通流量的监测数据,探讨了空气颗粒物污染的时空动态规律以及气象、交通对颗粒物浓度变化的影响.结果表明: 2013、2014、2015年,南昌市PM2.5浓度(70.92 μg·m-3>53.70 μg·m-3>43.65 μg·m-3)、PM10浓度(119.72 μg·m-3>86.11 μg·m-3>73.32 μg·m-3)逐年降低,并呈现出夏季低(PM2.5和PM10平均浓度分别为36.74、69.20 μg·m-3)、冬季高(PM2.5和PM10平均浓度分别为74.29、111.64 μg·m-3)的季节动态和由城市中心向郊区递减的城乡梯度变化; PM2.5/PM10值(0.595>0.584>0.557)逐年降低,并且表现出城市中心高、城市边缘低的空间分布格局;PM2.5、PM10浓度受到多种气象因素的影响,与气压、温度、相对湿度、风速、降水量、日照时数显著相关,各种气象因子对PM2.5、PM10浓度的影响存在差异;车流量会显著提高周边PM2.5浓度,但对PM10浓度影响不明显. 相似文献
32.
Els L.R. Swennen Pieter C. Dagnelie Aalt Bast 《Biochemical and biophysical research communications》2008,367(2):383-387
Damage to healthy tissue is a major limitation of radiotherapy treatment of cancer patients, leading to several side effects and complications. Radiation-induced release of pro-inflammatory cytokines is thought to be partially responsible for the radiation-associated complications. The aim of the present study was to investigate the protective effects of extracellular ATP on markers of oxidative stress, radiation-induced inflammation and DNA damage in irradiated blood ex vivo. ATP inhibited radiation-induced TNF-α release and increased IL-10 release. The inhibitory effect of ATP on TNF- α release was completely reversed by adenosine 5′-O-thiomonophosphate, indicating a P2Y11 mediated effect. Furthermore, ATP attenuated radiation-induced DNA damage immediate, 3 and 6 h after irradiation. Our study indicates that ATP administration alleviates radiation-toxicity to blood cells, mainly by inhibiting radiation-induced inflammation and DNA damage. 相似文献
33.
具有RNA裂解活性的DNA分子称为脱氧核酶。它是经过体外选择技术经多次筛选获得的。脱氧核酶在切割与其互补的RNA底物分子时具有极高的特异性和切割效率,有望成为新的RNA灭活工具。 相似文献
34.
Lymphocytes from the organized gut-associated lymphoid tissues (GALT) of adult guinea pigs were examined for surface markers characteristic of T and B lymphocytes and for their capacity to function as effector cells in mitogen-induced cellular cytotoxicity (MICC) and antibody-dependent cellular cytotoxicity (ADCC) reactions. GALT lymphocytes formed rosettes with rabbit erythrocytes, a T-cell marker, and underwent proliferative responses in vitro in the presence of phytohemagglutinin (PHA), concanavalin A (Con A), and pokeweed mitogen (PWM). GALT lymphocytes were cytotoxic in vitro for erythrocyte and DBA mastocytoma targets in the presence of PHA. A population of GALT lymphocytes bound aggregated γ-globulin; however, they functioned poorly in ADCC reactions. Thus, organized GALT in the guinea pig contains lymphocytes capable of functioning in T-cell-dependent MICC reactions but either lacks the effector cell population which mediates ADCC or contains an effector cell which functions poorly in ADCC. 相似文献
35.
The incubation of human peripheral blood lymphocytes (PBL) with the natural killer (NK)-sensitive MOLT-4 cell line results in PBL-target cell conjugate formation by certain lymphocyte subpopulations. Following velocity sedimentation, the PBL depleted of these conjugate-forming subpopulations are markedly diminished in the ability to mediate either antibody-dependent cellular cytotoxicity (ADCC) or NK activity. The immediate testing of highly pure PBL subpopulations isolated from the NK target conjugates does not reveal the expected recovery of augmented ADCC or NK levels. Following in vitro incubation, however, the PBL NK target-binding subpopulations do manifest augmented levels of both NK and ADCC, whereas the depleted PBL continue to display diminished NK and ADCC levels. In addition, the degree of augmented NK and ADCC levels recovered by the NK target-binding PBL subpopulations appears dependent on both the time and the temperature of in vitro incubation. Moreover, the ADCC recovery patterns are identical to those observed for NK activity regardless of the time and temperature of in vitro incubation. These results directly demonstrate that the PBL subpopulations isolated from certain NK target cells are functionally enriched in the ability to mediate from ADCC and NK activity. 相似文献
36.
产紫杉醇内生真菌枝状枝孢霉MD2的发酵条件优化 总被引:2,自引:0,他引:2
[目的]通过优化内生真菌枝状枝孢霉MD2的发酵条件,提高10-去乙酰巴卡亭Ⅲ (10-DAB)和紫杉醇(Taxol)的产量.[方法]采用单因素试验分析不同的培养基初始pH值、培养温度、摇床转速和培养时间对10-DAB和紫杉醇产量的影响,优化枝状枝孢霉MD2的培养条件;以YES为基本培养基,采用单因素试验和正交试验分析添加苯甲酸钠、苯丙氨酸、丝氨酸和甘氨酸4种前体物对10-DAB和紫杉醇产量的影响,优化枝状枝孢霉MD2的培养基组分.[结果]优化后发酵条件为:在初始pH为5.0的300 mL YES培养基中,添加15 mg/L苯甲酸钠、25 mg/L苯丙氨酸、5 mg/L丝氨酸、15 mg/L甘氨酸,接种1 mL枝状枝孢霉MD2的孢子悬液(107-10s个孢子/mL),28.0℃、220 r/min发酵培养12d.在此条件下,枝状枝孢霉MD2的生物量、10-DAB和紫杉醇的产量分别为15.5 g/L、471.5 μg/L和569.5 μg/L,与初始发酵条件相比,分别提高了1.3、3.6和3.4倍.[结论]首次获得了枝状枝孢霉MD2生产10-DAB和紫杉醇的较适摇瓶发酵条件,可为进一步放大发酵培养提供参考. 相似文献
37.
Shah HN Rajakaruna L Ball G Misra R Al-Shahib A Fang M Gharbia SE 《Systematic and applied microbiology》2011,34(1):81-86
Strains (n = 99) of Staphylococcus aureus isolated from a large number of clinical sources and tested for methicillin sensitivity were analysed by MALDI-TOF-MS using the Weak Cation Exchange (CM10) ProteinChip Array (designated SELDI-TOF-MS). The profile data generated was analysed using Artificial Neural Network (ANN) Analysis modelling techniques. Seven key ions identified by the ANNs that were predictive of MRSA and MSSA were validated by incorporation into a model. This model exhibited an area under the ROC curve value of 0.9147 indicating the potential application of this approach for rapidly characterising MRSA and MSSA isolates. Nearly all strains (n = 97) were correctly assigned to the correct group, with only two aberrant MSSA strains being misclassified. However, approximately 21% of the strains appeared to be in a process of transition as resistance to methicillin was being acquired. 相似文献
38.
B. M. Baltazar A. L. Scharen W. E. Kronstad 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1990,79(3):422-426
Summary Differences in levels of resistance toSeptoria tritici blotch were observed in plants with a specific height-reducing gene. When the gene Rht
2 was present either as an isoline or in the progeny, a higher degree of resistance was found. The most susceptible plants were observed in populations carrying the Rht
1 gene. Associations, as determined by phenotypic correlations, were detected betweenSeptoria tritici blotch and tall stature, late heading, and maturity. Plants having short stature, early heading, early maturity, and acceptable levels of resistance were identified in the F2 population whenRht
2 was present. Results of this study indicated that wheat breeders must select the appropriate dwarfing source that may confer resistance and grow large F2 populations, in order to increase the probability of obtaining desired genotypes. 相似文献
39.
Three group 10 complexes containing nido-carborane diphosphine, [NiCl(PPh3){7,8-(PPh2)2-7,8-C2B9H10}] (1), [PdCl(PPh3){7,8-(PPh2)2-7,8-C2B9H10}] · 1.25CH2Cl2 (2) and [PtCl(PPh3){7,8-(PPh2)2-7,8-C2B9H10}] · 2.5CH2Cl2 (3) have been synthesized by the reactions of [M(PPh3)2Cl2] (M = Ni, Pd, Pt) with closo carborane diphosphine 1,2-(PPh2)2-1,2-C2B10H10 in ethanol. For complex 3, it could also be obtained under solvothermal condition. All three complexes were characterized by elemental analysis, FT-IR, 1H and 13C NMR spectroscopy and X-ray structure determination. Single crystal structures show that their structures are similar to each other. In each complex, the nido [7,8-(PPh2)2-7,8-C2B9H10]−, which resulted from the degradation of the initial closo ligand 1,2-(PPh2)2-1,2-C2B10H10 during the reaction process, was coordinated bidentately through the P atoms to M(II) ion, and this resulted in a stable five-membered chelating ring between the bis-diphosphine ligand and the metal. The coordination mode of the metal can be described as a slightly distorted square-planar, in which the remaining two positions were occupied by one Cl− and one PPh3 group. 相似文献
40.
Sultan Ullah Yujin Park Muhammad Ikram Sanggwon Lee Chaeun Park Dongwan Kang Jungho Yang Jinia Akter Sik Yoon Pusoon Chun Hyung Ryong Moon 《Bioorganic & medicinal chemistry》2018,26(21):5672-5681
Pigmentation disorders are attributed to excessive melanin which can be produced by tyrosinase. Therefore, tyrosinase is supposed to be a vital target for the treatment of disorders associated with overpigmentation. Based on our previous findings that an (E)-β-phenyl-α,β-unsaturated carbonyl scaffold can play a key role in the inhibition of tyrosinase activity, and the fact that cinnamic acid is a safe natural substance with a scaffolded structure, it was speculated that appropriate cinnamic acid derivatives may exhibit potent tyrosinase inhibitory activity. Thus, ten cinnamamides were designed, and synthesized by using a Horner-Emmons olefination as the key step. Cinnamamides 4 (93.72% inhibition), 9 (78.97% inhibition), and 10 (59.09% inhibition) with either a 2,4-dihydroxyphenyl, or 4-hydroxy-3-methoxyphenyl substituent showed much higher mushroom tyrosinase inhibition at 25?µM than kojic acid (18.81% inhibition), used as a positive control. Especially, the two cinnamamides 4 and 9 having a 2,4-dihydroxyphenyl group showed the strongest inhibition. Docking simulation with tyrosinase revealed that these three cinnamamides, 4, 9, and 10, bind to the active site of tyrosinase more strongly than kojic acid. Cell-based experiments carried out using B16F10 murine skin melanoma cells demonstrated that all three cinnamamides effectively inhibited cellular tyrosinase activity and melanin production in the cells without cytotoxicity. There was a close correlation between cellular tyrosinase activity and melanin content, indicating that the inhibitory effect of the three cinnamamides on melanin production is mainly attributed to their capability for cellular tyrosinase inhibition. These results imply that cinnamamides having the (E)-β-phenyl-α,β-unsaturated carbonyl scaffolds are promising candidates for skin-lighting agents. 相似文献