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21.
通过对小鼠补体受体Ⅱ型基因(CR2)进行定点突变,然后将野生型和突变型小鼠CR2/1(MCR2/1)及人CR2(hCR2)用电穿孔方法导入小鼠SP2/0进行表达,采用免疫组织化学等方法鉴定阳性细胞系。用EB病毒对转染阳性细胞进行感染,EBER-1杂交结果显示,仅转染hCR2和突变型MCR2(mtMCR2)的SP2/0细胞感染了EB病毒,前者感染EB病毒的阳性率较后者高很多。这为进一步研究EB病毒进入细胞的机制及建立EB病毒相关的鼻咽癌动物模型奠定了良好的基础。 相似文献
22.
23.
Xin Sun Yunfeng Guo Shengdu Yang Kai Wang Lan Xie Bai Xue 《Macromolecular chemistry and physics.》2023,224(15):2300072
The poly(l -lactic acid) (PLLA)/carbon nanomaterials composite foams with hierarchical surface microstructural and internal conductive pathways are successfully prepared by a simple crystallization-assisted rapid phase separation (CARPS). The dimension and morphology of carbon nanomaterials can induce different crystallization forms to construct the hierarchical surface microstructure, and they are distributed on the phase interface of solvent and non-solvent to form conductive pathways. It is found that the heterogeneous nucleation of nanomaterials promotes a significant increase in crystallinity, and a stacked granular structure formed on the surface promotes the increase of the water contact angle to 148.7°. Foams with interconnecting pore structures contribute to the formation of 85.3% porosity and 12.33 g g−1 oil absorption. Carbon nanomaterials are distributed on the pore walls of the porous foam, which converts the foam from an insulating material to a conducting polymer. Furthermore, the uniform distribution of nanomaterials significantly affects the thermal stability of the PLLA. In belief, the multifunctional biodegradable foam, prepared by a CARPS method, makes it promising for industrial production and has potential applications in electrical conductivity, oil-water separation, and many other fields. 相似文献
24.
以对氨基苯磺酸修饰聚乙二醇端头,制备兼具刚性与极性端头的聚合物,考察其制备LB膜与自组装膜的条件,用原子力/摩擦力显微镜表征自组装膜的表面形貌,对其微摩擦性能进行初步的探讨。 相似文献
25.
评价低温保存板层角膜移植材料的效果。方法将15只人尸角膜分三组保存2年:4℃甘油脱水法,角膜液氮冷冻法,全眼球液氮冷冻法。并做透射电镜观察。结果第一组中,角膜胶原纤维排列紊乱,疏松,缺乏连续性,可见广纤维变性,纤维间可见极低电子密度灶。 相似文献
26.
目的: 评价准分子激光屈光性角膜切削术治疗放射状角膜切开术后残余近视散光的预测性、稳定性和安全性。方法: 对52 眼 R K 术后残余近视散光患者行再次 P R K 治疗, 并连续随访两年以上。术前残余球镜屈光度- 375±132 D,残余柱镜屈光度- 236±125 D, 最佳矫正视力均≥08。结果: 术后 6 个月球镜屈光度- 032±024 D, 柱镜屈光度- 078±052 D, 裸眼视力≥10 者46 眼 (8846% ), 术后 24 个月球镜屈光度- 037±042 D, 柱镜屈光度- 056±037 D, 裸眼视力≥10 者 42 眼 (8076% )。最佳矫正视力下降 1 行以上者 3 眼 (576% ), 实际球镜矫正度与预期矫正度相差10 D 以内 50 眼 (9015% ), 柱镜相差 10 D以内51 眼 (9807% )。结论: P R K 治疗 R K 术后残余近视散光的两年随访结果表明, 该方法预测性强、稳定性好和安全性高, 特别在矫正残余散光方面, 其结果令人满意。 相似文献
27.
Gene cloning and sequencing of BmK AS and BmK AS-1, two novel neurotoxins from the scorpion Buthus martensi Karsch. 总被引:1,自引:0,他引:1
Based on the known amino acid sequences of BmK AS and BmK AS-1, the gene specific primers were designed and synthesized for 3' and 5' RACE (Rapid Amplification of cDNA Ends). Their partial cDNA fragments obtained by 3' and 5' RACE were cloned and sequenced, and the full length cDNA sequences of BmK AS and BmK AS-1 were then completed by overlapping their two partial cDNA sequences, respectively. The predicted amino acid sequences both consist of 85 amino acid residues including a putative signal peptide of 19 residues and a mature toxin of 66 residues. They are different in 17 amino acid residues, among them 11 residues in the mature toxin. The predicted amino acid sequences of BmK AS and BmK AS-1 were almost consistent with those determined and revised (personal communication), only different in one and two residues at their COO-terminal parts, respectively. Based on the determined cDNA sequences, and using the total DNAs isolated from the scorpion venom glands as a template, the genomic DNAs of BmK AS and BmK AS-1 were also amplified by PCR and sequenced. It showed that no intron was inserted in their open reading frames, while in the exon of signal peptide sequences of other Na+, K+ and Cl- channel toxins from the same scorpion, an intron is usually found. However, the Northern blot hybridization results indicated that the sizes of their mRNA should be around 800 bp. Their extra sequences around 400 bp which might function as an intron should be located at their 5' untranslated regions. 相似文献
28.
Correlation analysis of numbers of colony-forming progenitor cells was used as an approach to the quantitation of human pluripotent stem cells. Marrow specimens were obtained from 24 patients with untreated acute myeloblastic leukemia, 22 patients under treatment, and 29 patients with no hematologic malignant disease. Three classes of progenitor cells were assayed: burst-forming units dependent on erythropoietin (BFU-E), colony-forming units dependent on erythropoietin (CFU-E), and granulopoietic progenitors (CFU-C). Significant positive correlations between numbers of BFU-E, CFU-E, and CFU-C were found in all 3 groups of patients. In contrast, no such positive correlations were seen between marrow blasts and any of the classes of colony-forming progenitors. These results were compatible with a shared relationship of the colony-forming progenitors to a pluripotent cell of origin and raised the possibility that the immediate progenitors of the blasts may not be any of the myelopoietic progenitor cells monitored in these studies. 相似文献
29.
In a study of 331 term pregnancies a four-quadrant technique was used to obtain amniotic fluid index measurements, and the results were compared with the current widely used single-pocket measurement. In contrast to the "2-cm rule," the amniotic fluid index measurements consistently demonstrated higher sensitivity in predicting poor fetal outcome with no decrease in specificity. It was noted that pregnancies with an index of < or = 8 cm showed higher incidences of meconium staining, cesarean delivery for fetal distress, abnormal fetal heart rate monitoring and Apgar scores of < or = 7 or less at one minute. 相似文献
30.
Objective The study was to explore the safety, firmness and convenience of the fascia around the ischial spine as a new fixation site for the vaginal fornix. Methods Between June 2007 and January 2008, detailed dissections and related measurements of the regions around the ischial spine were performed on 10 Chinese female cadavers (3 unembalmed and 7 embalmed cadavers). At the same time, the sacrospinous ligament,the fascia on the ischial spine, the iliococcygeus fascia as well as the vaginal fornix were exposed and the pull-out strength sequentially tested using a digital push-pull force gauge. Results The fascia on the ischial spine was firm and strong, with a thickness of 3 about mm. No major vessels or nerves were observed on the ischial spine. The greatest pullout strengths of the sacrospinous ligament,the fascia on the ischial spine, the iliococcygeus fascia as well as the vaginal fornix were (102±26),(64±15),(33±8)and(32±6)N, respectively. Conclusion The fascia at 1 cm from anterior lateral ischial spine, free of major vessels and nerves, is safe and strong and could be used as a new site for suspension in vaginal prolapse. 相似文献