Wind tunnel study of wind structure at a mountainous bridge location

Yan, Lei,Guo, Zhen S.,Zhu, Le D.,Flay, Richard G.J. Techno-Press 2016 Wind and Structures, An International Journal (WAS Vol.23 No.3

Wind tunnel tests of a 1/2200-scale mountainous terrain model have been carried out to investigate local wind characteristics at a bridge location in southeast Tibet, China. Flows at five key locations on the bridge at deck level were measured for 26 directions. It was observed that wind characteristics (including mean wind velocity and overall turbulence intensity) vary significantly depending on the approaching wind direction and measurement position. The wind inclination angle measured in the study fluctuated between $-18^{\circ}$ and $+16^{\circ}$ and the ratio of mean wind velocity to reference wind velocity was small when the wind inclination angles were large, especially for positive wind inclination angles. The design standard wind speed and the minimum critical wind speed for flutter rely on the wind inclination angle and should be determined from the results of such tests. The variation of wind speed with wind inclination angles should be of the asymmetry step type. The turbulence characteristics of the wind were found to be similar to real atmospheric flows.

Clonal Spread of Carbapenem Resistant Acinetobacter baumannii ST92 in a Chinese Hospital during a 6-Year Period

Lei Huang,Liying Sun,Yan Yan 한국미생물학회 2013 The journal of microbiology Vol.51 No.1

The carbapenem resistance rate of Acinetobacter baumannii in our hospital has increased steadily since 2004. The molecular epidemiology of carbapenem resistant A. baumannii (CRAB) clinical isolates was characterized by multilocus sequence typing (MLST) and rep-PCR in parallel, with pandrug susceptible A. baumannii (PSAB) used as control. MLST was performed to determine the sequence types (STs), and eBURST algorithm was used to analyze their relatedness. Carbapenem resistance related genes (oxa-23, oxa-24, oxa-51, oxa-58, imp, vim, and adeB) were screened using Polymerase Chain Reaction (PCR) method. 23 STs were identified in the 65 included isolates, with ST92 being the predominant clone. PSAB clustered into more singletons than CRAB. The positivity of oxa-23 and adeB correlated with high level carbapenem resistance (MICIPM>32 mg/L, MICMEM >32 mg/L) of CRAB ST92 isolates in 2009, which was different from the resistance pattern (MICIPM≤4 mg/L, 8 mg/L ≤MICMEM≤16 mg/L) of CRAB ST92 isolates in 2004. These observations suggest that clonal spread of CRAB ST92 isolates longitudinally is the possible reason for carbapenem resistance rate increase and correlate with high level carbapenem resistance in our hospital.

Efficacy and Safety of the Safe Triangular Working Zone Approach in Percutaneous Vertebroplasty for Spinal Metastasis

Yan Bi Cong,Fan Yan Feng,Tian Qing Hua,Wang Tao,Huang Zhi Long,Song Hong Mei,Li Ying,Jiao Lei,Wu Chun Gen 대한영상의학회 2022 Korean Journal of Radiology Vol.23 No.9

Objective: This study aimed to assess the technical feasibility, efficacy, and safety of the safe triangular working zone (STWZ) approach applied in percutaneous vertebroplasty (PV) for spinal metastases involving the posterior part of the vertebral body. Materials and Methods: We prospectively enrolled 87 patients who underwent PV for spinal metastasis involving the posterior part of the vertebral body, with or without the STWZ approach, from January 2019 to April 2022. Forty-nine patients (27 females and 22 males; mean age ± standard deviation [SD], 57.2 ± 11.6 years; age range, 31–76 years) were included in group A (with STWZ approach), accounting for 54 vertebrae. Thirty-eight patients (18 females and 20 males; 59.1 ± 10.9 years; 29–81 years) were included in group B (without STWZ approach), accounting for 57 vertebrae. Patient demographics, procedure-related variables, and pain relief as assessed using the visual analog scale (VAS) were collected at different time points. Tumor recurrence in the vertebrae after PV was analyzed using Kaplan–Meier curves. Results: The STWZ approach was successful from T1 to L5 without severe complications. Cement filling was satisfactory in 47/54 (87.0%) and 25/57 (43.9%) vertebrae in groups A and B, respectively (p < 0.001). Cement leakage was not significantly different between groups A and B (p = 1.000). Mean VAS score ± SD before and 1 week and 1, 3, 6, 9, and 12 months after PV were 7.6 ± 1.8, 4.2 ± 2.0, 2.7 ± 1.9, 1.9 ± 1.5, 1.7 ± 1.4, 1.7 ± 1.1, and 1.6 ± 1.3, respectively, in group A and 7.2 ± 1.7, 4.0 ± 1.3, 3.4 ± 1.6, 2.4 ± 1.2, 1.8 ± 1.0, 1.4 ± 0.5, and 1.7 ± 0.9, respectively, in group B. Kaplan–Meier analysis showed a lower tumor recurrence rate in group A than in group B (p = 0.001). Conclusion: The STWZ approach may represent a new, safe, alternative/auxiliary approach to target the posterior part of the vertebral body in the PV for spinal metastases.

An Acid-/Base-Degradable Epoxy Resin Cured by 1,3,5-Triacroylamino- hexahydro-s-triazine Derivative

Lei Wang,Shijing Yan,Lei Zhang,Yuliang Mai,Weihao Li,Hao Pang 한국고분자학회 2021 Macromolecular Research Vol.29 No.7

The degradation and recycling of waste epoxy resin products is an urgent environmental problem. To solve this issue, we use acid-/base-degradable 1,1’,1"- (1,3,5-hexahydro-s-triazine-1,3,5-triyl) tris(3-ethylamino-propan-1-one) (TAHT-EA) as curing agent to introduce the hexahydro-s-triazine (HT) ring structure into the cross-linking network to prepare degradable epoxy resin. Specifically, 1,3,5-triacryloylhexahydro- 1,3,5-triazine (TAHT) and ethylamine quickly complete the Aza-Michael addition reaction at the interface of chloroform and water droplets under the catalysis of water. The FTIR spectra, NMR spectrum and mass spectrum show that mono- and bis-addition products of ethylamine coexist in the product in which the content of the primary addition product reaches 97%. TAHT-EA can be decomposed by acid and base solutions. Through NMR analysis of the degradation products, it can be explained that the degradation mechanisms are different. The breaking of amide bonds and HT rings in acid solution and the cracking of amide bonds in base solution are speculated to be the main mechanisms under these two different circumstances, respectively. We tested the mechanical, thermal and degradation properties of the epoxy resin cured by TAHT-EA, and compared it with the epoxy resin cured by 4,4'-diaminodiphenylmethane and triethylenetetramine. TAHT-EA-cured epoxy resin shows comparable mechanical properties with Young’s modulus up to 2.05 GPa and tensile strength up to 70.9 MPa. What is more, it degrades completely by 1 M H+/OH- solution at 60℃ within 36 h. Nevertheless, it exhibited a relatively low crosslinked density (633 mol/m3) and low heat resistance (the initial decomposition temperature is lower than 205℃). Overall, TAHT-EA cured epoxy resin has the potential to gradually replace traditional thermosetting resin, thereby solving the environmental problems caused by discarded epoxy resin products.

Experimental Study on Y-shaped Bridge Under 3-dimentional Earthquake Ground Motions

Yan Lei,Li Qingning 대한토목학회 2017 KSCE JOURNAL OF CIVIL ENGINEERING Vol.21 No.6

Based on similar theory and multi-dimensional seismic design theory, a Y-shaped bridge model with the scale ratio of 1:20 was made to conduct the seismic simulation shaking table test in this paper. Failure mode and dynamic responses of Y-shaped bridge under different seismic wave spectrum, different peak accelerations and different seismic excitation directions were studied. The experimental results show that, the piers mostly exhibit bending failure mode and the vertical ground motion has a great influence on the development of cracks in girders. Dynamic responses of the Y-shaped bridge are different and presented different laws when three different seismic waves were applied. Seismic wave is input along the direction of the branch straight girder, which is the most unfavorable earthquake input direction when calculating the peak acceleration at the top of piers. Multi-dimension seismic excitation should be considered when calculating the width of the expansion joint between adjacent girders. The horizontal bidirectional seismic excitation can satisfy the design requirements of strain response at the bottom of pier. The model structure would cause vertical vibration during its horizontal seismic excitation, and vertical seismic excitation exerts more significant influence on the vertical vibration of branch straight girder.

A Study of Urodynamic Parameters at Different Bladder Filling Stages for Predicting Upper Urinary Tract Dilatation

Lei Lyu,Ya Xiong Yao,Er Peng Liu,Yan Ping Zhang,Hui Jie Hu,Feng Ping Ji,Qing Song Pu,Xing Huan Yang,Qing Wei Wang,Yan Wang,Jian Guo Wen 대한배뇨장애요실금학회 2022 International Neurourology Journal Vol.26 No.1

Purpose: To identify more accurate predictors of upper urinary tract dilatation (UUTD) in neurogenic bladder (NB) children, we studied the relationship among urodynamic parameters at different bladder filling stages, detrusor leak point pressure (DLPP) and UUTD. Methods: A total of 158 children (3–16 years) with NB were included and then divided into 2 groups according to whether their NB diagnosis was complicated with UUTD: the UUTD group (39 patients) and those without UUTD group (control group, 119 patients). The bladder filling phase was divided into 3 equal parts: the early, middle, and end filling stages. The bladder compliance (BC) and detrusor pressure (△Pdet) at each phase and DLPP at the end filling stage were recorded. Results: A BC<8 mL/cm H2O both in the middle and end stages is more specific than a BC<9 mL/cm H2O in the end stage (72%, 73%, vs. 66%), and △Pdet >8 cm H2O in the early stage, 20 cm H2O in the middle stage and 25 cm H2O in the end stage are more sensitive than △Pdet >40 cm H2O in the end stage (82%, 85%, 85%, vs. 49%). A DLPP cutoff value of 20 cm H2O showed higher sensitivity for predicting UUTD than 40 cm H2O. Conclusions: Low BC and a high △Pdet in the middle and end filling stages are more accurate factors than classic indicators for predicting UUTD. In addition, a DLPP value of >20 cm H2O in the end bladder filling stage shows high sensitivity.

High-resolution Anorectal Manometry in the Diagnosis of Functional Defecation Disorder in Patients With Functional Constipation: A Retrospective Cohort Study

Yan Zhao,Xiaoyang Ren,Wen Qiao,Lei Dong,Shuixiang He,Yan Yin 대한소화기 기능성질환∙운동학회 2019 Journal of Neurogastroenterology and Motility (JNM Vol.25 No.2

Background/Aims High-resolution anorectal manometry (HRAM) has been considered a first-line diagnostic tool for functional defecation disorder. However, clinical studies on HRAM used in constipation patients are very limited and few studies have reported the characteristics of anorectal pressure in Chinese patients. The aim of this study is to investigate the characteristics of motility data in a cohort of Chinese patients with functional constipation. Methods A total of 82 consecutive patients with functional constipation who underwent a standardized HRAM were retrospectively enrolled in this study. The functional defecation disorder was classified into Rao’s types. Results The mean age of 82 patients was 51 years (range, 16–83 years). Indications for anorectal manometry were functional constipation for all patients. The mean resting pressure was 69.2 ± 21.2 mmHg (range, 24.5–126.9 mmHg). The mean maximum squeezing pressure was 198.4 ± 75.6 mmHg (range, 54.2–476.9 mmHg). The mean length of the anal high pressure zone was 3.4 ± 1.0 cm (range, 0.6–4.9 cm). Sixty (73.2%) patients were diagnosed as functional defecation disorder. In attempted defecation, type I was most common (n = 24), followed by type II (n = 12), type III (n = 11), and type IV (n = 13) that were present on HRAM according to Rao’s classification. In all 60 patients with functional defecation disorder, 37 were women and 23 were men. Men were significantly more likely than women to have functional defecation disorder (92.0% vs 64.9%, P = 0.014). Conclusion HRAM could be used as a test for the diagnosis of functional defecation disorder and functional defecation disorder is common in Chinese patients with functional constipation.

Wind tunnel study of wind structure at a mountainous bridge location

Lei Yan,Zhen S. Guo,Le D. Zhu,Richard G. J. Flay 한국풍공학회 2016 Wind and Structures, An International Journal (WAS Vol.23 No.3

Wind tunnel tests of a 1/2200-scale mountainous terrain model have been carried out to investigate local wind characteristics at a bridge location in southeast Tibet, China. Flows at five key locations on the bridge at deck level were measured for 26 directions. It was observed that wind characteristics (including mean wind velocity and overall turbulence intensity) vary significantly depending on the approaching wind direction and measurement position. The wind inclination angle measured in the study fluctuated between -18 and +16 and the ratio of mean wind velocity to reference wind velocity was small when the wind inclination angles were large, especially for positive wind inclination angles. The design standard wind speed and the minimum critical wind speed for flutter rely on the wind inclination angle and should be determined from the results of such tests. The variation of wind speed with wind inclination angles should be of the asymmetry step type. The turbulence characteristics of the wind were found to be similar to real atmospheric flows.

The encounter of time and space

Yan Lei 한국콘텐츠학회 2023 ICCC International Digital Design Invitation Exhib Vol.2023 No.5

Exploring the beneficial role of telmisartan in sepsis-induced myocardial injury through inhibition of high-mobility group box 1 and glycogen synthase kinase-3β/nuclear factor-κB pathway

Yan Jin,Hong Wang,Jing Li,Minyan Dang,Wenzhi Zhang,Yan Lei,Hao Zhao 대한생리학회-대한약리학회 2020 The Korean Journal of Physiology & Pharmacology Vol.24 No.4

In the present experimental study, cecal ligation and puncture significantly increased the myocardial injury assessed in terms of excess release of creative kinase-MB (CK-MB), cardiac troponin I (cTnI), interleukin (IL)-6 and decrease of IL-10 in the blood following 12 h of laparotomy procedure as compared to normal control. Also, a significant increase in protein expression levels of high-mobility group box 1 (HMGB1) and decreased phosphorylation of glycogen synthase kinase-3β (GSK-3β) was observed in the myocardial tissue as compared to normal control. A single independent administration of telmisartan (2 and 4 mg/kg) and AR-A014418 (1 and 2 mg/kg) substantially reduced sepsis-induced myocardial injury in terms of decrease levels of CK-MB, cTnI and IL-6, HMGB1, GSK-3β and increase in IL-10 and p-GSK-3β in the blood in sepsis- subjected rats. The effects of telmisartan at dose 4 mg/kg and AR-A014418 at a dose of 2 mg/kg were significantly higher than the telmisartan at a dose of 2 mg/kg and AR-A014418 1 mg/kg respectively. Further, no significant effects on different parameters were observed in the sham control group in comparison to normal. Therefore it is plausible to suggest that sepsis may increase the levels of angiotensin II to trigger GSK-3β-dependent signaling to activate the HMGB1/receptors for advanced glycation end products, which may promote inflammation and myocardial injury in sepsis-subjected rats.