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。     

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.     

Therapeutic effects of total alkaloids of Tripterygium wilfordii Hook f. on collagen-induced arthritis in rats

Ethnopharmacological relevance

Tripterygium wilfordii Hook f. is one of Traditional Chinese Medicines which is commonly used to treat rheumatoid arthritis (RA). The total alkaloids were the main constituent part of Tripterygium wilfordii Hook f. It has a great significance to study the effects of the total alkaloids of Tripterygium wilfordii Hook f. (ATW) on RA.

Aim of the study

This paper aims at investigating the therapeutic effect of ATW on RA and its possible mechanism, and providing a theoretical and experimental basis for the clinical use of ATW.

Materials and methods

The model of wistar rats of type II collagen-induced arthritis (CIA) was made, and the rats were perfused a stomach with ATW for 4 weeks continuously. Then the levels of interleukin (IL)-6, IL-8, tumor necrosis factor (TNF)-<alpha>, in the serum of CIA rats were detected by enzyme linked immunosorbent assay (ELISA), and the joint pathological section of CIA rats was observed by hematoxylin and eosin (HE) staining method and the expression of IL-6, IL-8, nuclear factor kappa B (NF-κB), TNF-α were measure by immunohistochemistry staining method.

Results

Compared with model group, ATW could significantly reduce paw swelling and suppresse articular cartilage degenerated. The results also found that there was significant reduction levels of IL-6, IL-8 and TNF-α in serum of CIA rats treated with ATW and ATW inhibited the expression of IL-6, IL-8, NF-κB, TNF-α in synovial tissue.

Conclusion

ATW not only could inhibit the symptom of CIA rats significantly but also could inhibit the production of IL-6, IL-8, TNF-α in serum and the expression of IL-6, IL-8, NF-κB and TNF-α in synovial tissue targeting the inflammatory. ATW would be a drug as a novel botanical drug for the treatment of RA.