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101.
In this study, the autolytic clinker microsphere with clinker as core and polyvinyl pyrrolidone (PVP) as coating film was prepared. Pretreatment of clinker with silane coupling agent was firstly processed during the preparation. To investigate the autolytic mechanism, the microstructures of the autolytic clinker microsphere at different curing ages were observed using environmental scanning electron microscopy (ESEM), equipped with an energy dispersive spectrometer (EDS). The autolytic stages were also identified based on the microstructural evolution. The influence of pretreatment degree on autolytic behavior was also studied by measurements of micro-morphology and isothermal calorimetry. Experimental results indicated that the compressive strength recovery of specimens was increased by 15–19% due to the addition of autolytic clinker microspheres. The recovery of compressive strength was also improved with the increase of pH value. The improvements in compressive strength recovery of specimens with microspheres were in the range of 15–19%, 15–31%, 25–36%, and 29–50% with the pH value of 7, 8, 10, and 12, respectively. It was also found that inner damage of cement-based matrix had greater recovery when pre-cracked specimens were cured in alkaline environments. 相似文献
102.
Safeer Abbas Ali Ahmed Ayesha Waheed Wasim Abbass Muhammad Yousaf Sbahat Shaukat Hisham Alabduljabbar Youssef Ahmed Awad 《Materials》2022,15(10)
Recycled rubber waste (RW) is produced at an alarming rate due to the deposition of 1.5 billion scrap tires annually around the globe, which causes serious threats to the environment due to its open land filling issues. This study investigates the potential application of RW in concrete structures for mitigating the alkali–silica reaction (ASR). Various proportions of RW (5%, 10%, 15%, 20%, and 25%) partially replaced the used aggregates. RW was procured from a local rubber recycling unit. Cubes, prisms, and mortar bar specimens were prepared using a mixture design recommended by ASTM C1260 and tested for evaluating the compressive and flexural strengths and expansion in an ASR conducive environment for specimens incorporating RW. It was observed that the compressive and flexural strength decreased for specimens incorporating RW compared to that of the control specimens without RW. For example, an 18% and an 8% decrease in compressive and flexural strengths, respectively, were observed for specimens with 5% of RW by aggregates volume at 28 days. Mortar bar specimens without RW showed an expansion of 0.23% and 0.28% at 14 and 28 days, respectively, indicating the potential ASR reactivity in accordance with ASTM C1260. A decrease in expansion was observed for mixtures incorporating RW. Specimens incorporating 20% of RW by aggregate volume showed expansions of 0.17% at 28 days, within the limit specified by ASTM C1260. Moreover, specimens incorporating RW showed a lower reduction in compressive and flexural strengths under an ASR conducive environment compared to that of the control specimen without RW. Micro-structural analysis also showed significant micro-cracking for specimens without RW due to ASR. However, no surface cracks were observed for specimens incorporating RW. It can be argued that the use of RW in the construction industry assists in reducing the landfill depositing issues with the additional benefit of limiting the ASR expansion. 相似文献
103.
Geopolymer foams with different pore structures can be used in construction, water treatment, and heavy metal adsorption. The preparation of high porosity geopolymer foams using vegetable oil as a foam stabilizer is a feasible and cost-effective route. In this study, metakaolin-based geopolymer foams with hierarchical pore structures were fabricated by adding H2O2 as the foaming agent with palm olein as the foam stabilizer. The effects of H2O2 and palm olein content on the chemical features and pore structure of geopolymer foams were evaluated. Water absorption, thermal conductivity, and mechanical behaviors of geopolymer foams were also investigated. The results indicate that fatty acid salt surfactants were generated in situ in the geopolymer matrix due to the addition of palm olein. Geopolymer foams with H2O2 and palm olein addition possess a homogeneously concentrated macropore distribution. Palm olein exhibits a refining effect on intrinsic pores formed by geopolymerization. In addition, using appropriate amounts of palm olein and H2O2, geopolymer foams can achieve higher open porosity and better pore connectivity, resulting in the improvement of water absorption and thermal insulation capacity. 相似文献
104.
为提高盾叶薯蓣试管苗的移栽成活率,在组织培养的基础上,对盾叶薯蓣人工种子中人工种皮、人工胚乳制作,人工种子一次性成苗及移栽成活率等问题进行了初步研究,结果表明,人工种子快速繁殖的最适条件为:从盾叶薯蓣愈伤组织表面切取2~3mm小块茎,包埋在2.5%海藻酸钠里,滴入2%CaCl2中反应8~10min,人工胚乳MS/2+IAA0.4mg/L直接播种在MS/2培养基上,一次性成苗率可达100%左右,移栽成活率高达85%。说明以组织培养为基础的盾叶薯蓣人工种子快速繁殖技术具有一定的优越性。 相似文献
105.
目的观察浅低温干预预防复苏后综合征的临床疗效。方法126例在心肺脑复苏后常规高级生命支持治疗基础上,予浅低温治疗;将床旁多参数中央监护系统的温度传感器置于腋下进行连续监测,将患者体温控制在32—35℃,24h后恢复常温治疗。72h后观察疗效,以急性呼吸窘迫综合征(ARDS)评分方法和多系统功能障碍(MODS)评分方法分别进行评分。结果治疗前ARDS评分(12.31±4.68)分,治疗后(6.99±3.05)分,治疗前后比较差异有统计学意义(P〈0.05);治疗前MODS评分1级8例,2级56级,3级62例,治疗后1级22例,2级79例,3级25例。治疗后1级、2级病例增加,3级病例减少,与治疗前比较差异有统计学意义(P〈0.05);126例中发生复苏后综合征28例;预后情况:126例中死亡49例(38.89%),出院但有脑损害19例(15.08%),出院无脑损害58例(46.03%)。结论在心肺脑复苏后常规高级生命支持治疗基础上采用浅低温方法可以有效预防复苏后综合征,减少死亡率。 相似文献
106.
目的观察中药内服结合外敷治疗原发性肝癌腹水的临床疗效。方法将60例脾虚血瘀型原发性肝癌腹水患者随机分为治疗组和对照组,各30例。对照组口服安体舒通,治疗组采用健脾活血利水内服方及逐水药外敷,疗程均为15天。观察两组腹水、生活质量、中医症状改善情况。结果治疗组腹水的改善优于对照组(P<0.05);治疗后治疗组Karnofsky评分较治疗前提高(P<0.05),对照组降低(P<0.05);两组治疗前后差值比较有统计学意义(P<0.05);治疗后治疗组患者腹胀、腹痛等症状明显改善(P<0.05),且较对照组改善显著(P<0.05)。结论中药内服结合外敷治疗原发性肝癌腹水疗效显著,并可改善临床症状,提高患者生活质量。 相似文献
107.
目的:观察杜仲苷对IL-1β刺激大鼠体外软骨细胞的增殖及Ⅱ型胶原蛋白分泌的影响。方法:利用IL-1β刺激建立体外大鼠软骨细胞炎性模型,实验分为空白组、IL-1β组、10μM杜仲苷组、100μM杜仲苷组、500μM杜仲苷组、1000μM杜仲苷组;空白组加入10%FBS培养液,IL-1β组加入10ng/mL IL-1β+10%FBS培养液,4个不同浓度杜仲苷组分别加入10μM、100μM、500μM、1000μM杜仲苷+10ng/mL IL-1β+10%FBS培养液,分别培养48小时,采用CCK8检测软骨细胞增殖活力及Ⅱ型胶原蛋白的分泌。结果:IL-1β组的OD值低于空白组(P〈0.05);4个不同浓度杜仲苷组的OD值均高于IL-1β组(P〈0.05),且存在一定的量效关系;4个不同浓度杜仲苷组的Ⅱ型胶原蛋白表达均高于IL-1β组(P〈0.05),且存在有一定的量效关系。结论:杜仲苷可以提高体外大鼠软骨细胞炎性环境下的增殖活力,促进Ⅱ型胶原蛋白的分泌,表明杜仲苷对体外大鼠软骨细胞有一定的抗炎保护作用。 相似文献
108.
Ali K. Shargh Aude Picard Rostislav Hrubiak Dongzhou Zhang Russell J. Hemley Shanti Deemyad Niaz Abdolrahim Saveez Saffarian 《Proceedings of the National Academy of Sciences of the United States of America》2022,119(27)
Formation of vitreous ice during rapid compression of water at room temperature is important for biology and the study of biological systems. Here, we show that Raman spectra of rapidly compressed water at greater than 1 GPa at room temperature exhibits the signature of high-density amorphous ice, whereas the X-ray diffraction (XRD) pattern is dominated by crystalline ice VI. To resolve this apparent contradiction, we used molecular dynamics simulations to calculate full vibrational spectra and diffraction patterns of mixtures of vitreous ice and ice VI, including embedded interfaces between the two phases. We show quantitatively that Raman spectra, which probe the local polarizability with respect to atomic displacements, are dominated by the vitreous phase, whereas a small amount of the crystalline component is readily apparent by XRD. The results of our combined experimental and theoretical studies have implications for detecting vitreous phases of water, survival of biological systems under extreme conditions, and biological imaging. The results provide additional insight into the stable and metastable phases of H2O as a function of pressure and temperature, as well as of other materials undergoing pressure-induced amorphization and other metastable transitions.Life as we know it on Earth depends on water. However, water also poses a critical challenge to life when it freezes at atmospheric pressure and low temperatures. The crystallization of H2O to form hexagonal ice () under these conditions is accompanied by its well-known expansion, which has a dramatic impact on the structure and function of living cells. This crystallization of H2O disrupts biological membranes and intracellular organization in living organisms and also displaces and concentrates salts and nutrients in the space between crystals (1). Like many liquids, however, rapid cooling of H2O at ambient pressure to below its glass-transition temperature results in the formation of an amorphous phase known as low-density amorphous ice. Amorphous solid H2O provides a chance for biological functions to survive where life otherwise cannot exist. Low-density amorphous ice is not the only amorphous form of H2O. Ice Ih transforms to high-density amorphous (HDA) ice by application of ∼1 GPa of pressure at temperatures below 130 K (2, 3). In addition, a distinct, very-high-density amorphous state (vHDA) can form by isobaric heating and cooling of the HDA (4). low-density amorphous, high-density amorphous, and very-high-density amorphous state ice thus represent the three dominant, solid amorphous forms of H2O at low temperatures.Solid amorphous phases of H2O are broadly important in biology and biological applications. That amorphous H2O which can exist over a broad range of temperatures, from cryogenic conditions to room temperature, is particularly interesting in the context of biological systems. Managing ice crystals is vital for extremophiles to survive damaging effects of H2O crystallization. These organisms inhibit the growth of ice crystals and regulate the size and shape of the crystals using special antifreeze proteins (5, 6). Additionally, amorphous phases of H2O are important in preserving biological samples in cryotomography applications. In cryotomography, the amorphous H2O at low temperature is utilized routinely for sample preparation (7, 8), and significant efforts have been devoted to increase information obtained from cryotomography techniques. The low-temperature regime of amorphous H2O routinely accessed in cryotomography creates challenges for light microscopy due to freezing of index-matching medium and objectives, which result in lowering the resolution of light microscopy in these applications. Room-temperature amorphous phases of H2O are, therefore, advantageous for light microscopy applications and further development of techniques such as correlative light and electron microscopy (9–11).While formation of amorphous phases of H2O below 200 K has been reported in many studies (2, 3, 12–16), a particularly interesting result is the observation of the Raman signature of HDA ice during fast compression of water at room temperature and moderate pressures (17). On the other hand, independent X-ray diffraction (XRD) measurements of H2O on fast compression could not verify the formation of amorphous H2O above 200 K (18). Here, we report high-resolution micro-Raman and synchrotron XRD measurements conducted in parallel in rapidly compressed samples of water in diamond anvil cells (DACs). Our findings, that are supported by molecular dynamics simulations, shed light on the nature of the HDA ice at room temperature and reconciled conflicting previous reports. 相似文献
109.
目的 探讨采用基于“人工智能(AI)的骨龄辅助评价系统(上海初云医疗科技有限公司与四川大学华西第二医院合作开发)”(以下简称为AI系统)对完全性生长激素缺乏症(CGHD)患儿诊断及骨龄评价准确性。方法 选择2014年7月至2019年11月,于四川大学华西第二医院确诊的66例来自四川地区CGHD患儿为研究对象,纳入研究组。选择同期于病例收集医院儿童保健科进行骨龄测定的67例来自四川地区身高达标儿童作为对照,纳入对照组。对每例受试儿进行左手腕关节正位X射线摄片骨龄测定,由2位医师采用《TW2骨龄评分法中国未成年人南方标准》(以下简称为TW2CHN)》与《TW3骨龄评分法标准》(以下简称为TW3),盲法评价受试儿TW2CHN-桡、尺、掌指骨(RUS)与TW2CHN-腕骨(carpal)、TW2CHN-20、TW3-RUS及TW3-carpal骨龄(以下简称为5种传统骨龄),以及以同性别、年龄身高达... 相似文献
110.