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1.
目的 以超声剪切波弹性成像(SWE)分析兔VX2肝癌移植瘤模型TACE后肿瘤周围肝组织(以下简称瘤周)纤维化状态。方法 选取12只新西兰兔,于超声引导下经皮穿刺肝左叶实质,植入VX2肝癌组织,建立兔VX2肝癌移植瘤模型。将模型兔随机分入TACE组和Sham组,每组6只。对TACE组于建模后2~3周经股动脉插管行肝固有动脉造影,之后对TACE组注入碘化油乳剂,对Sham组注入生理盐水。于术前及术后2周以常规超声观察肿瘤大小,以SWE检测肿瘤、瘤周及肝右叶组织硬度。术后2周检测血清丙氨酸转氨酶(ALT)、天冬氨酸转氨酶(AST)、肌酐(Cr)及血尿素氮(BUN)水平。处死动物取肿瘤及瘤周组织,观察肝细胞形态、评估纤维化程度;以Western blot法检测瘤周组织胶原Ⅰ和胶原Ⅲ蛋白表达水平。采用Spearman相关性分析评价瘤周纤维化程度与组织硬度的相关性。结果 对12只兔均成功建模,经股动脉插管行肝动脉造影成功率100%(12/12)。2组术前肿瘤体积、肝组织硬度及血清学指标差异均无统计学意义(P均>0.05)。术后2周,相比Sham组,TACE组肿瘤体积缩小,肿瘤及瘤周组织硬度增加,血清ALT、AST升高(P均<0.05)。病理检查显示,TACE组瘤周肝细胞水肿明显,Sham组偶见肝细胞水肿,TACE组瘤周纤维化程度高于Sham组(P<0.01);TACE组瘤周胶原Ⅰ和胶原Ⅲ蛋白表达水平高于Sham组(P均<0.01)。Spearman相关性分析结果表明,瘤周纤维化程度与肝脏硬度呈正相关(r=0.67,P=0.02)。结论 TACE后VX2肝癌模型兔瘤周纤维化程度加重;SWE可用于评估肝纤维化程度。 相似文献
2.
Ana Carpio & Rafael Gonzá lez-Albaladejo 《Communications In Computational Physics》2022,31(1):257-292
We propose a computational model to study the growth and spread of bacterial biofilms on interfaces, as well as the action of antibiotics on them. Bacterial membranes are represented by boundaries immersed in a fluid matrix and subject to interaction forces. Growth, division and death of bacterial cells follow dynamic energy
budget rules, in response to variations in environmental concentrations of nutrients,
toxicants and substances released by the cells. In this way, we create, destroy and enlarge boundaries, either spherical or rod-like. Appropriate forces represent details of
the interaction between cells, and the interaction with the environment. We can investigate geometrical arrangements and the formation of porous structures. Numerical
simulations illustrate the evolution of top views and diametral slices of small biofilm
seeds, as well as the action of antibiotics. We show that cocktails of antibiotics targeting
active and dormant cells can entirely eradicate a biofilm. 相似文献
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《Health & place》2022
IntroductionWe extend previous research to illustrate how individual, interpersonal and neighbourhood factors in a high-density urban setting in Vancouver, Canada, shape social connectedness experiences of community-dwelling older adults during the first wave of the COVID-19 pandemic.MethodsWe conducted 31 semi-structured interviews and collected objective measures of loneliness and social connectedness (surveys).ResultsThree dimensions of the neighbourhood environment influenced social connectedness: (i) interactions with neighbours, (ii) involvement with neighbourhood-based organizations, and (ii) outdoor pedestrian spaces. Seventy-one percent of participants felt a strong sense of belonging to their local community, while 39% were classified as high or extremely lonely.SummaryMany participants leveraged pre-existing social ties to maintain connections during the pandemic. However, volunteer outreach was vital for more isolated older adults. Although many participants felt lonely and isolated at times, the relative ease and accessibility with which they could connect with others in their neighbourhood environment, may have helped mitigate persistent loneliness.ConclusionStrategies that foster social connectedness over the longer term, need to prioritize the needs of older adults who face multiple barriers to equitable social participation. 相似文献
5.
《Journal of endodontics》2022,48(5):572-596
IntroductionCulture-independent molecular studies have shown a broad spectrum of bacterial taxa that persist after chemomechanical procedures (CMP). Therefore, this study systematically reviewed these reports to explore the prevalence of bacteria in post-instrumentation samples of root canals from permanent teeth, especially of as-yet-uncultivated/difficult-to-culture bacteria.MethodsElectronic databases were searched from 2007 to January 2021. Clinical studies using culture-independent molecular methods to identify species-level taxa before and after CMP were included. Studies were critically appraised using the Joanna Briggs Institute Prevalence Critical Appraisal Checklist and the funnel plot analysis. The meta-analysis was performed on the prevalence of as-yet-uncultivated/difficult-to-culture bacterial taxa using RStudio.ResultsA total of 3781 titles were screened, but only 20 studies were included. The most frequent species in post-instrumentation samples were Streptococcus spp., Leptotrichia buccalis, Fusobacterium nucleatum, and Capnocytophaga ochracea. The detection frequency of some species increased after CMP, including mainly Firmicutes members such as streptococci, Enterococcus faecium, Selenomonas noxia, and Solobacterium moorei. The prevalence (confidence interval) of difficult-to-culture species was as follows: Dialister invisus, 17% (7%–29%); Solobacterium moorei, 14% (8%–23%); Bacteroidaceae [G-1] bacterium HMT 272, 13% (5%–23%); and Filifactor alocis, 11% (3%–23%).ConclusionsThe prevalence of as-yet-uncultivated/difficult-to-culture bacterial taxa in post-instrumentation samples was low. The persistent species belonged mainly to the phylum Firmicutes, and streptococci were the major members. Future larger clinical studies on the composition of the whole bacterial community that persist after CMP are still necessary for a better understanding of bacterial interactions and their clinical significance in the treatment outcome. 相似文献
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High-Order Positivity-Preserving Well-Balanced Discontinuous Galerkin Methods for Euler Equations with Gravitation on Unstructured Meshes 下载免费PDF全文
Weijie Zhang Yulong Xing Yinhua Xia & Yan Xu 《Communications In Computational Physics》2022,31(3):771-815
In this paper, we propose a high-order accurate discontinuous Galerkin
(DG) method for the compressible Euler equations under gravitational fields on unstructured meshes. The scheme preserves a general hydrostatic equilibrium state and
provably guarantees the positivity of density and pressure at the same time. Comparing with the work on the well-balanced scheme for Euler equations with gravitation
on rectangular meshes, the extension to triangular meshes is conceptually plausible
but highly nontrivial. We first introduce a special way to recover the equilibrium state
and then design a group of novel variables at the interface of two adjacent cells, which
plays an important role in the well-balanced and positivity-preserving properties. One
main challenge is that the well-balanced schemes may not have the weak positivity
property. In order to achieve the well-balanced and positivity-preserving properties
simultaneously while maintaining high-order accuracy, we carefully design DG spatial discretization with well-balanced numerical fluxes and suitable source term approximation. For the ideal gas, we prove that the resulting well-balanced scheme, coupled with strong stability preserving time discretizations, satisfies a weak positivity
property. A simple existing limiter can be applied to enforce the positivity-preserving
property, without losing high-order accuracy and conservation. Extensive one- and
two-dimensional numerical examples demonstrate the desired properties of the proposed scheme, as well as its high resolution and robustness. 相似文献
9.
目的 探讨冲刺间歇训练时两种恢复方式(积极性恢复 vs. 消极性恢复)对士兵运动能力和训练效果的影响。方法 选取18名男性武警士兵完成6组冲刺间歇训练(30 s Wingate全力蹬车试验),间歇期(4 min)分别进行消极性恢复(即在功率自行车上休息)和积极性恢复(以1.1 W/kg负荷继续蹬车),每次Wingate试验时(不包括间歇期)记录峰值功率(PP)、平均功率(MP)、疲劳指数(FI)、总做功(TW)和心率(HR)等参数。结果 与消极性恢复比较,积极性恢复PP在第2次Wingate试验时降低(P<0.05),MP和HR在第4~6次Wingate试验时升高,差异均有统计学意义(P<0.05),FI和TW差异无统计学意义(P>0.05)。结论 积极性恢复可提高冲刺间歇训练后期的训练效果, 士兵应根据训练方案选择合理的恢复方式。 相似文献
10.
环状RNA(circular RNA,circRNA)是广泛存在于多物种细胞中结构稳定、高度保守、表达量丰富、可充当微小RNA海绵、具有剪切和转录调控、亲代基因修饰功能的内源性单链闭合circRNA。circRNA主要通过套索驱动的环化、内含子配对驱动的循环、内含子环化方式合成。在胃癌发生和进展过程中,不同种类的circRNA作用不一致。部分circRNA在胃癌组织中表达上调,通过微小RNA/p53/上皮细胞-间充质转化轴等机制促进胃癌细胞增殖、迁移;相反,部分circRNA在胃癌组织中表达下调,通过与miRNA间的海绵作用抑制胃癌细胞增殖和迁移。目前,已在人类唾液、胃液、血浆等成分中检测出胃癌相关的circRNA,提示circRNA具有作为胃癌诊断标志物的潜力。干预circRNA表达提高抗肿瘤药物敏感度,体外合成具有抑癌基因作用的circRNA,或下调具有癌基因作用的circRNA下游信号蛋白是胃癌治疗的有效手段。circRNA为胃癌的诊断和治疗提供了新的思路。 相似文献