The Uncertainty Propagation for Carbon Atomic Interactions in Graphene under Resonant Vibration Based on Stochastic Finite Element Model

Graphene is one of the most promising two-dimensional nanomaterials with broad applications in many fields. However, the variations and fluctuations in the material and geometrical properties are challenging issues that require more concern. In order to quantify uncertainty and analyze the impacts of uncertainty, a stochastic finite element model (SFEM) is proposed to propagate uncertainty for carbon atomic interactions under resonant vibration. Compared with the conventional truss or beam finite element models, both carbon atoms and carbon covalent bonds are considered by introducing plane elements. In addition, the determined values of the material and geometrical parameters are expanded into the related interval ranges with uniform probability density distributions. Based on the SFEM, the uncertainty propagation is performed by the Monte Carlo stochastic sampling process, and the resonant frequencies of graphene are provided by finite element computation. Furthermore, the correlation coefficients of characteristic parameters are computed based on the database of SFEM. The vibration modes of graphene with the extreme geometrical values are also provided and analyzed. According to the computed results, the minimum and maximum values of the first resonant frequency are 0.2131 and 16.894 THz, respectively, and the variance is 2.5899 THz. The proposed SFEM is an effective method to propagate uncertainty and analyze the impacts of uncertainty in the carbon atomic interactions of graphene. The work in this paper provides an important supplement to the atomic interaction modeling in nanomaterials.     

Burst Pressure Prediction of Subsea Supercritical CO2 Pipelines

To improve transportation efficiency, a supercritical CO₂ pipeline is the best choice for large-scale and long-distance transportation inshore and offshore. However, corrosion of the pipe wall will occur as a result of the presence of free water and other impurities present during CO₂ capture. Defects caused by corrosion can reduce pipe strength and result in pipe failure. In this paper, the burst pressure of subsea supercritical CO₂ pipelines under high pressure is investigated. First, a mechanical model of corroded CO₂ pipelines is established. Then, using the unified strength theory (UST), a new burst pressure equation for subsea supercritical CO₂ pipelines is derived. Next, analysis of the material’s intermediate principal stress parameters is conducted. Lastly, the accuracy of the burst pressure equation of subsea supercritical CO₂ pipelines is proven to meet the engineering requirement by experimental data. The results indicate that the parameter b of UST plays a significant role in determining burst pressure of pipelines. The study can provide a theoretical basis and reference for the design of subsea supercritical CO₂ pipelines.     

胎儿下肢长骨骨重的非对称性研究

作者研究胎儿下肢长骨骨重的非对称性,测量了佳未斯地区胎儿88具下肢长骨,两侧骨重相差10%为非对称性标准。结果表明:除女性腓骨外,胎儿男、女性各骨骨重侧别差异均无统计学意义,长骨骨重的非对称性占绝大多数,右侧重多于左侧重。     

复方丹参滴丸联合心得安对肝纤维化及门脉高压的影响

1999年6～9月，我们采用复方丹参滴丸联合心得安治疗肝炎肝硬化30例，以观察其降低门脉高压及肝纤维化程度的变化，现报告如下。     

利用条件错误发现率方法识别抑郁症和失眠症的多效性位点

背景 抑郁症和失眠症常共病存在,两者存在一些共同的发病机制,并可能受相同的多效性基因调控。既往全基因组关联研究（GWAS）一般采用单性状研究,在解释基因多效性方面存在一定的狭窄性。目的 识别与失眠症和抑郁症相关的遗传变异位点,检验抑郁症和失眠症是否存在共同的遗传因素。方法 抑郁症GWAS数据来自精神疾病遗传学联盟（PGC）,共包含246 363例抑郁症患者和561 190例正常对照。失眠症GWAS数据来自睡眠障碍知识门户,共包含1 331 010例受试者。采用条件错误发现率（cFDR）和联合的条件错误发现率（ccFDR）方法筛选与抑郁症和失眠症相关的遗传位点,采用通路富集分析检验这些位点的生物学功能。结果 抑郁症和失眠症存在显著的多效性富集现象。利用cFDR方法,以cFDR<0.01作为显著性阈值,鉴定出21个易感位点与抑郁症相关（其中17个是新识别的）,38个易感位点与失眠症相关（其中28个是新识别的）。以ccFDR<0.05为显著性阈值,识别出16个多效性位点与抑郁症和失眠症均相关,其中15个是本研究新识别的。通路富集分析结果显示,与抑郁症和失眠症均关联的易感位点富集于突触传递相关通路,如突触后密度（GO：0014069,P=4.91E-04,FDR=4.84E-03）、不对称突触（GO：0032279,P=5.09E-0,FDR=4.84E-03）、突触后膜神经递质受体水平的调节（GO：0099072,P=5.11E-04,FDR=1.69E-02）。结论 失眠症与抑郁症之间存在多效性富集现象,其共病机制与突触传递有关。     

Association Between Nap and Reported Cognitive Function and Role of Sleep Debt: A Population-Based Study

Background and PurposeThe relationship between napping and cognition remains controversial. This study aimed to investigate the association between napping and cognition according to sleep debt in the Korean adult population.MethodsA population-based nationwide cross-sectional survey was conducted in 2018. A two-stage stratified random sample of Koreans aged ≥19 years was selected and evaluated using questionnaires by trained interviewers. Cognitive function was assessed using the Mail-In Cognitive Function Screening Instrument (MCFSI). Sleep habits on weekdays and weekends, napping, and subjective sleep requirements were assessed using the questionnaires. Accumulated sleep debt was calculated by subtracting the weekly average sleep duration from subjective sleep requirements. Sleep quality, daytime sleepiness, insomnia, depression, demographics, and comorbidities were assessed. Participants were grouped into those with sleep debt ≤60 min and those with sleep debt >60 min. Multiple linear regression was used to estimate the independent association between the factors and cognition.ResultsIn total, 2,501 participants were included in the analysis. Naps were reported in 726 (29.0%) participants (nappers). The mean MCFSI score was higher in nappers (3.4±3.6) than in non-nappers (2.3±3.0) (p<0.001). Multiple linear regression controlling for age, alcohol, smoking, depression, insomnia, daytime sleepiness, sleep quality, and education revealed that 30 to 60 min of napping was associated with worse cognitive function in participants with sleep debts ≤60 min, while >60 min of napping was associated with better cognitive function in participants with sleep debts >60 min.ConclusionsIn general, naps are associated with worse cognitive function in the Korean adult population. However, for those with sleep debt of >60 min, naps for >60 min were associated with better cognitive function.     

内生真菌SEF15927对截短侧耳素的微生物羟化研究

目的 研究植物内生真菌SEF15927对截短侧耳素的转化作用.方法 利用液体培养生长细胞对截短侧耳素进行生物转化.发酵液经乙酸乙酯萃取和硅胶柱层析分离获得一个羟化产物.运用质谱和核磁共振光谱鉴定结构.结果 转化产物为2-羟基截短侧耳素.结论 植物内生真菌SEF15927为一具有高转化率的截短侧耳素羟化菌株,     

Quantitative analysis by reversed-phase high-performance liquid chromatography and retinal neuroprotection after topical administration of moxonidine

AIM: To determine moxonidine in aqueous humor and iris-ciliary body by reversed-phase high performance liquid chromatography (RP-HPLC), and to evaluate the retinal neuroprotective effect after topical administration with moxonidine in a high intraocular pressure (IOP) model. METHODS: The eyes of albino rabbits were administered topically and ipsilaterally with 0.2% moxonidine. A RP-HPLC method was employed for the identification and quantification of moxonidine between 2 and 480min, which presented in the aqueous humor and iris-ciliary body. Flash electroretinography (F-ERG) amplitude and superoxide dismutase (SOD) level were measured between day 1 and day 15 after topical administration with moxonidine in a rabbit model of high IOP. Histological and ultrastructural observation underwent to analyze the changes of retinal morphology, the inner retinal layers (IRL) thickness, and retinal ganglion cell (RGC) counting. RESULTS: Moxonidine was detectable between 2 and 480min after administration, and the peak concentration developed both in the two tissues at 30min, 0.51 μg/mL in aqueous humor and 1.03 μg/g in iris-ciliary body. In comparison to control, F-ERG b-wave amplitude in moxonidine eyes were significantly differences between day 3 and day 15 (P<0.01) in the high IOP model; SOD levels were significantly higher at all time-points (P<0.01) with a maximum level of 20.29 U/mgprot at day 15; and RGCs were significantly higher (P<0.05). CONCLUSION: Moxonidine is a viable neuroprotective agent with application to high IOP model. All layers of retina, including RGC layer, retinal nerve fiber layer and INL, are more preserved after moxonidine administration. SOD plays a neuroprotective role in ocular hypertension-mediated RGC death.