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1.
彭成 《世界中医药》2020,15(9):1233-1236
系统中药学是基于现代中药学学科的开创者凌一揆教授"大中药"的思想,是研究中药复杂系统品种、品质、制药、药性、功效、应用等关键要素发生、发展、变化的科学。本文论述了系统中药学的科学内涵,报告了在系统中药学指导下益母草"品质制性效应"的研究实践。  相似文献   
2.
桃金娘科植物丁香Eugenia caryophyllata在我国具有悠久的栽培和使用的历史,是药食同源植物,其药理活性丰富,在食品、药品、香精香料等行业具有十分广泛的用途,是中医、蒙医常用的药材。目前已有丁香药理作用及化学成分方面的报道,但临床上的研究进展较少。该文拟对丁香化学成分及药理作用的研究情况进行总结;通过查阅文献,介绍丁香在中医、蒙医本草中的记载情况;结合计算机软件整理丁香在传统蒙医临床中的使用频率以及药对配伍;并从丁香的药性、功能主治、临床应用等方面探讨蒙医学对丁香的使用情况,为后续对丁香的研究提供参考。  相似文献   
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富血小板血浆和富血小板纤维蛋白(PRF)目前已成熟地应用于口腔医学领域,随着制备技术与基础研究的不断深入,PRF的衍生物也相继出现并应用于口腔临床中。本文就PRF衍生物的演变、制备技术、生物学特性及医学研究进展作一综述。  相似文献   
5.
目的通过有限元分析探讨直线通路微创开髓洞型对上颌第一前磨牙力学性能的影响。方法收集2018年6月至2020年6月于四川大学华西口腔医院口腔颌面外科就诊患者因正畸或牙周病拔除的上颌第一前磨牙,从中选取牙体完整、根尖孔发育完成的双根管牙20颗,对其显微CT(micro-CT)数据进行三维重建,在三维模型中模拟传统开髓洞型、桁架开髓洞型与直线通路微创开髓洞型的开髓与根管治疗(每组样本量均为20个)。建模完成后进行有限元分析,记录纵向及斜向负载模式下各组模型的牙颈部von Mises等效应力峰值(VM)并观测各组模型的应力分布模式。结果纵向负载模式下,3种开髓洞型牙颈部颊侧和腭侧VM分别为:桁架开髓洞型[(146.0±12.9)和(167.6±15.9)MPa],直线通路微创开髓洞型[(142.6±13.7)和(168.1±17.4)MPa],传统开髓洞型[(188.7±13.4)和(200.9±25.7)MPa]。与传统开髓洞型相比,桁架开髓洞型(t=9.01,P<0.001;t=4.59,P<0.001)和直线通路微创开髓洞型(t=9.64,P<0.001;t=3.76,P=0.004)均可有效降低根管治疗后上颌第一前磨牙颊侧和腭侧牙颈部VM,同时缓解应力在[牙合]面集中力加载区域、牙颈部及牙根的集中。在斜向负载模式下得到了相似的结果。在两种负载模式下,桁架开髓洞型与直线通路微创开髓洞型间颊腭侧牙颈部VM差异均无统计学意义(P>0.05)。结论直线通路微创开髓洞型可以有效保护根管治疗后上颌第一前磨牙的力学性能,具有一定的临床可行性。  相似文献   
6.
《Drug discovery today》2022,27(2):384-389
Proposals to waive intellectual property rights (IPRs) on coronavirus 2019 (COVID-19)-related developments have gained considerable support among politicians, including from US President Biden, academics, nongovernmental organizations (NGOs), the media, and the general public. However, there are surprisingly few reflections about the short- and long-term consequences for medical innovation, particularly the development of new drugs and vaccines. In this feature, I reflect on the consequences for innovative entrepreneurial companies, the incentives to innovate, and consequences for international knowledge flows to low- and middle-income countries. I conclude that waiving IPRs reduces opportunities for entrepreneurial companies to attract sufficient funding for developing medical innovations. Low- and middle-income countries might suffer reduced knowledge inflows in the absence of IPRs that undermine their ability to develop medical innovations.  相似文献   
7.
目的 合成兼具亲水及抗菌性的新型硅橡胶口腔印模材料,并探讨相关性能,为其在牙科领域中的进一步应用奠定基础。 方法 在前期预实验的基础上确定了新型硅橡胶的基本配方,并以6%聚醚改性硅油作为润湿剂赋予其良好的亲水性。将自行合成的碘代长链烷基季铵盐修饰的纳米抗菌SiO2无机填料,按0%、1%、2%、3%、4%及5%的比例添加至亲水硅橡胶印模材料中,以期赋予其抗菌性,并以商品化的硅橡胶产品作为对照。测量各组硅橡胶材料的力学性能、润湿性、细节再现性、尺寸稳定性及调和时间;同时通过薄膜密着法与CCK-8法检测硅橡胶材料的抗菌性与细胞毒性;扫描电镜(SEM)观察新型硅橡胶的微观形貌。 结果 当抗菌填料含量超过4%时,新型硅橡胶力学性能明显下降(P<0.05);与对照组相比,不同组别在不同时间节点接触角、细节再现性完好且线性尺寸变化率无显著变化(P>0.05);抗菌填料的加入不会对调和时间产生影响(P>0.05)。当加入4%抗菌填料时,抗菌率可达95.26%,展现出良好的抗菌性;所有组别细胞毒性反应差异无统计学意义(P>0.05),说明硅橡胶材料无明显细胞毒性。硅橡胶试样断面SEM观察显示填料与硅橡胶基体的相容性良好,在基体内部分布均匀。 结论 含6%聚醚改性硅油的亲水性硅橡胶中加入4%的抗菌无机填料可以获得兼具亲水与抗菌性能的新型硅橡胶口腔印模材料,这为进一步临床应用提供了实验依据。  相似文献   
8.
Beyond the classic sensory systems, the sense of time is most likely involved from foraging to navigation. As a prerequisite for assessing the role time is playing in different behavioral contexts, we further characterized the sense of time of a harbor seal in this study. Supra-second time intervals were presented to the seal in a temporal discrimination and a temporal bisection task. During temporal discrimination, the seal needed to discriminate between a standard time interval (STI) and a longer comparison interval. In the bisection task, the seal learnt to discriminate two STIs. Subsequently, it indicated its subjective perception of test time intervals as resembling either the short or long STI more. The seal, although unexperienced regarding timing experiments, learnt both tasks fast. Depending on task, time interval or duration ratio, it achieved a high temporal sensitivity with Weber fractions ranging from 0.11 to 0.26. In the bisection task, the prerequisites for the Scalar Expectancy Theory including a constant Weber fraction, the bisection point lying close to the geometric mean of the STIs, and no significant influence of the STI pair condition on the probability of a long response were met for STIs with a ratio of 1:2, but not with a ratio of 1:4. In conclusion, the harbor seal's sense of time allows precise and complex judgments of time intervals. Cross-species comparisons suggest that principles commonly found to govern timing performance can also be discerned in harbor seals.  相似文献   
9.
The mechanical properties of solder alloys are a performance that cannot be ignored in the field of electronic packaging. In the present study, novel Sn-Zn solder alloys were designed by the cluster-plus-glue-atom (CPGA) model. The effect of copper (Cu) addition on the microstructure, tensile properties, wettability, interfacial characterization and melting behavior of the Sn-Zn-Cu solder alloys were investigated. The Sn29Zn4.6Cu0.4 solder alloy exhibited a fine microstructure, but the excessive substitution of the Cu atoms in the CPGA model resulted in extremely coarse intermetallic compound (IMC). The tensile tests revealed that with the increase in Cu content, the tensile strength of the solder alloy first increased and then slightly decreased, while its elongation increased slightly first and then decreased slightly. The tensile strength of the Sn29Zn4.6Cu0.4 solder alloy reached 95.3 MPa, which was 57% higher than the plain Sn-Zn solder alloy, which is attributed to the fine microstructure and second phase strengthening. The spreadability property analysis indicated that the wettability of the Sn-Zn-Cu solder alloys firstly increased and then decreased with the increase in Cu content. The spreading area of the Sn29Zn0.6Cu0.4 solder alloy was increased by 27.8% compared to that of the plain Sn-Zn solder due to Cu consuming excessive free state Zn. With the increase in Cu content, the thickness of the IMC layer decreased owing to Cu diminishing the diffusion force of Zn element to the interface.  相似文献   
10.
The Al-20Si-5Fe-3Cu-1Mg alloy was fabricated using selective laser melting (SLM). The microstructure and properties of the as-prepared SLM, post-treated SLM, and SLM with substrate plate heating are studied. The as-prepared SLM sample shows a non-uniform microstructure with four different phases: fcc-αAl, eutectic Al-Si, Al2MgSi, and δ-Al4FeSi2. With thermal treatment, the phases become coarser and the δ-Al4FeSi2 phase transforms partially to β-Al5FeSi. The sample produced with SLM substrate plate heating shows a relatively uniform microstructure without a distinct difference between hatch overlaps and track cores. Room temperature compression test results show that an as-prepared SLM sample reaches a maximum strength (862 MPa) compared to the heat-treated (524 MPa) and substrate plate heated samples (474 MPa) due to the presence of fine microstructure and the internal stresses. The reduction in strength of the sample produced with substrate plate heating is due to the coarsening of the microstructure, but the plastic deformation shows an improvement (20%). The present observations suggest that substrate plate heating can be effectively employed not only to minimize the internal stresses (by impacting the cooling rate of the process) but can also be used to modulate the mechanical properties in a controlled fashion.  相似文献   
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