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71.
72.
研究了谷朊粉的酸法改性及其在新型水性涂料中的应用.改性谷朊粉除具有优良的粘结性、流动性和流平性外,还提高了与涂料乳液的相容性,解决了谷朊粉原胶在涂料使用过程中的开裂严重,使得涂料具有更优的流平性和涂膜外观.  相似文献   
73.
能源植物资源的研究和开发   总被引:7,自引:0,他引:7  
植物能源是一种清洁的、方便的可替代能源,发展植物能源是解决矿石能源危机的可行的措施,生物汽油和生物柴油产业已得到初步发展和应用。按照能源植物所含特定化学物质的对能源植物进行类别划分,并结合我国的实际,提出我国适宜发展的能源植物品种。  相似文献   
74.
能源短缺和环境污染是当前人类社会所面临的巨大挑战,生物柴油的推广和应用是现阶段解决替代燃油的重要途径之一。黑皂树种子油是很好的生物柴油原料,目前在许多热带地区大力种植黑皂树。我国华南、西南地区的一些干旱荒地可以种植黑皂树。我们对黑皂树油在柴油机上的应用研究证明:黑皂树油在气温35℃条件下,可以直接在各种柴油机上起动和应用;黑皂树油中掺入20%的轻柴油,其黏度大大降低,冷机起动性能和热效率等均与轻柴油相当。因此,黑皂树油的应用比目前国外使用的生物柴油更经济,是一种很有发展前途的能源植物。  相似文献   
75.
暗示性运动是指个体观看静止图片时从中知觉到的运动.研究者采用高低认知水平两类暗示性运动刺激材料,借助"冻结帧"、直接观看、运动后效和f MRI适应等任务范式,探讨了注意和意识在暗示性运动加工中的作用及其记忆特点;并借助脑成像等技术,考察了颞中区、颞上皮层区、颞上沟、镜像神经元系统等脑区在暗示性运动加工中的作用.但由于暗示性运动加工涉及"视觉腹侧通路与背侧通路功能的分离与整合"问题,目前对相关研究结果和解释还存在争议,暗示性运动加工的认知神经机制仍有待于进一步研究.  相似文献   
76.
The impacts of global climatic change on belowground ecological processes of terrestrial ecosystems are still not clear. We therefore conducted an experiment in the subalpine coniferous forest ecosystem of the eastern edges of the Tibetan Plateau to study roots of Picea asperata seedlings and rhizosphere soil responses to soil warming and nitrogen availability from April 2007 to December 2008. The seedlings were subjected to two levels of temperature (ambient; infrared heater warming) and two nitrogen levels (0 or 25 g m−2year−1 N). We used a free air temperature increase from an overhead infrared heater to raise both air and soil temperature by 2.1 and 2.6°C, respectively. The results showed that warming alone significantly increased total biomass, coarse root biomass and fine root biomass of P. asperata seedlings. Both total biomass and fine root biomass were increased, but coarse root biomass was significantly decreased by nitrogen fertilization and warming combined with nitrogen fertilization. Warming induced a prominent increase in soil organic carbon (SOC) and NO3 -N of rhizosphere soil, while nitrogen fertilization significantly decreased SOC and NH4 +-N of rhizosphere soil. The warming, fertilization and warming × N fertilization interaction decreased soil microbial C significantly, but substantially increased soil microbial N. These results suggest that nitrogen deposition combined with warmer temperatures under future climatic change possibly will have no effect on fine root production of P. asperata seedlings, but could enhance the nitrification process of their rhizosphere soils in subalpine coniferous forests.  相似文献   
77.
目的研究微粒体甘油三酯转移蛋白MTP在脂肪酸诱导的胰岛B细胞凋亡过程中,转录水平受FoxO1调控的情况。方法脂肪酸处理胰岛8细胞系MIN6细胞,MTF和Hoechst染色检测细胞活力和凋亡情况;ReahimePCR检测MTP相对表达量;染色质免疫共沉淀技术检验FoxO1与肘即启动子区的结合情况;荧光素酶报告基因系统检测Fox01对MTP的转录调控情况。结果脂肪酸处理引起MIN6细胞活力下降、凋亡增加,使MIN6细胞中MTP mRNA水平上升;糖尿病模型小鼠胰岛中MTPmRNA水平上升;转录因子FoxO1的过表达可上调MTP的转录活性;ChIP—PCR结果显示FoxO1能与MZP的启动子区相结合。结论MTP在脂肪酸诱导胰岛B细胞凋亡的过程中,作为转录因子FoxO1的下游靶基因,转录水平受到FoxO1的调控。  相似文献   
78.
目的:评价XIVE种植体在上颌外伤前牙区即刻种植即刻负重修复的临床效果。方法:对26例前牙区单颗或多颗无法保留的外伤残根拔除后,即刻植入XIVE种植体,并即刻负重修复。种植体扭矩控制在35Ncm左右,初期稳定性良好。平均四到五个月后行永久修复。在植入后1、2、4个月对其进行临床及影像学检查。结果:32枚种植体有2枚种植体2周后出现松动,一个月后脱落,其余30枚均在预期时间内形成良好骨性愈合,最终完成修复。结论:上颌前牙区单颗或多颗牙外伤,残根无法保留者,行即刻种植即刻负重修复是可行。早期种植修复有利于减缓牙槽骨的吸收,保留软硬组织的形态,缩短疗程。  相似文献   
79.
Lin J  Shi L  Zhang M  Yang H  Qin Y  Zhang J  Gong D  Zhang X  Li D  Li J 《Cell Stem Cell》2011,8(4):371-375
The low success rate of somatic nuclear transfer (NT) is hypothesized to be mainly due to functional defects in the trophoblast cell lineage rather than the inner cell mass (ICM); this hypothesis, however, remains to be tested directly. Here we separated the ICMs from cloned blastocysts and aggregated the cloned ICM with two fertilization-derived (FD) tetraploid (4N) embryos. We found that the full-term development of cloned ICMs was dramatically improved after the trophoblast cells in the cloned blastocysts were replaced by cells from tetraploid embryos, thus providing direct evidence that defects in trophoblast cell lineage underlie the low success rate of somatic NT.  相似文献   
80.
Yin W  Jiang Y  Shen Z  Shao Z  Lu J 《PloS one》2011,6(6):e21030

Background

Adjuvant trastuzumab therapy has yielded conflicting results for overall survival, concerns about central nervous system (CNS) metastasis, and questions about optimal schedule. Therefore, we carried out a meta-analysis to assess the benefits of concurrent or sequential trastuzumab with adjuvant chemotherapy for early breast cancer patients with HER2-positive tumors.

Methods

Computerized and manual searches were performed to identify randomized clinical trials comparing adjuvant chemotherapy with or without trastuzumab in HER2-positive early breast cancer patients. Odds ratios were used to estimate the association between the addition of trastuzumab to adjuvant chemotherapy and various survival outcomes. The fixed-effects or random-effects model was used to combine data.

Findings

With six eligible studies identified, this analysis demonstrated that patients with HER2-positive breast cancer derived benefit in disease-free survival, overall survival, locoregional recurrence and distant recurrence (all P<0.001) from the addition of trastuzumab to adjuvant chemotherapy, whereas trastuzumab did worse in CNS recurrence as compared to the control group (P = 0.018). Furthermore, concomitant use of trastuzumab significantly lowered the hazard of death (P<0.001) but bore a higher incidence of CNS recurrence (P = 0.010), while statistical significance failed to be discerned for either overall survival (P = 0.069) or CNS metastasis (P = 0.374) between the sequential and observation arms.

Conclusion

This analysis verifies the efficacy of trastuzumab in the adjuvant setting. Additionally, our findings indirectly corroborate the superiority of concurrent trastuzumab to sequential use and also illuminate that prolonged survival is the possible reason for the higher incidence of CNS with trastuzumab versus observation.  相似文献   
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