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Numerical simulation and experimental study of non-stationary downburst outflow based on wall jet model

  • Yongli Zhong;Yichen Liu;Hua Zhang;Zhitao Yan;Xinpeng Liu;Jun Luo;Kaihong Bai;Feng Li
    • Wind and Structures
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    • v.38 no.2
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    • pp.129-146
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    • 2024
  • Aiming at the problem of non-stationary wind field simulation of downbursts, a non-stationary down-burst generation system was designed by adding a nozzle and program control valve to the inlet of the original wall jet model. The computational fluid dynamics (CFD) method was used to simulate the downburst. Firstly, the two-dimensional (2D) model was used to study the outflow situation, and the database of working conditions was formed. Then the combined superposition of working conditions was carried out to simulate the full-scale measured downburst. The three-dimensional (3D) large eddy simulation (LES) was used for further verification based on this superposition condition. Finally, the wind tunnel test is used to further verify. The results show that after the valve is opened, the wind ve-locity at low altitude increases rapidly, then stays stable, and the wind velocity at each point fluctuates. The velocity of the 2D model matches the wind velocity trend of the measured downburst well. The 3D model matches the measured downburst flow in terms of wind velocity and pulsation characteris-tics. The time-varying mean wind velocity of the wind tunnel test is in better agreement with the meas-ured time-varying mean wind velocity of the downburst. The power spectrum of fluctuating wind ve-locity at different vertical heights for the test condition also agrees well with the von Karman spectrum, and conforms to the "-5/3" law. The vertical profile of the maximum time-varying average wind veloci-ty obtained from the test shows the basic characteristics of the typical wind profile of the downburst. The effectiveness of the downburst generation system is verified.

Differential Subsampling with Cartesian Ordering Contrast-Enhanced Magnetic Resonance Angiography for the Preoperative Assessment of Anterolateral Thigh Flap

  • Yunfeng Shen;Xiucun Li;Chao Zhang;Hai Zhong;Weiqiang Dou
    • Korean Journal of Radiology
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    • v.23 no.8
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    • pp.803-810
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    • 2022
  • Objective: To investigate the clinical application of differential subsampling with Cartesian ordering (DISCO) contrast-enhanced (CE) magnetic resonance angiography for anterolateral thigh (ALT) flap transplantation, using operative findings as a reference. Materials and Methods: Thirty patients (21 males and nine females; mean age ± standard deviation, 45.5 ± 15.6 years) who were scheduled to undergo reconstruction with ALT flaps between June 2020 and June 2021 were included in the prospective study. Before ALT flap transplantation, patients were scanned using CE-DISCO imaging. All acquired DISCO images of the 60 lower limbs (both sides from each patient) were analyzed using maximum intensity projection and volume rendering methods. Two experienced radiologists were employed to examine the patterns of the lateral circumflex femoral artery (LCFA), its branches, and perforators and their skin termini, which were compared with the operative findings. Results: Using CE-DISCO, the patterns of the LCFA and its branches were clearly identified in all patients. Four different origins of the LCFA were found among the 60 blood vessels: type I (44/60, 73.3%), type II (6/60, 10.0%), type III (8/60, 13.3%), and type IV (2/60, 3.3%). Owing to a lack of perforators entering the skin, two patients did not undergo ALT flap transplantation. For the remaining 28 patients, the ALT flaps in 26 patients were successfully operated without flap reselection during the operation, while the remaining two patients underwent other surgical procedures due to the thin diameter of the perforator or injury of the perforator during the operation. The success rate of flap transplantation was 92.8% (26/28). All transplanted flaps exhibited good blood supply and achieved primary healing without infection or delayed healing. Conclusion: CE-DISCO imaging can be an effective method for preoperative perforator imaging before ALT flap transplantation.

MRI Findings in Trigeminal Neuralgia without Neurovascular Compression: Implications of Petrous Ridge and Trigeminal Nerve Angles

  • Hai Zhong;Wenshuang Zhang;Shicheng Sun;Yifan Bie
    • Korean Journal of Radiology
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    • v.23 no.8
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    • pp.821-827
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    • 2022
  • Objective: To determine the anatomical characteristics of the petrous ridge and trigeminal nerve in trigeminal neuralgia (TN) without neurovascular compression (NVC). Materials and Methods: From May 2017 to March 2021, 66 patients (49 female and 17 male; mean age ± standard deviation [SD], 56.8 ± 13.3 years) with TN without NVC and 57 controls (46 female and 11 male; 52.0 ± 15.6 years) were enrolled. The angle of the petrous ridge (APR) and angle of the trigeminal nerve (ATN) were measured using magnetic resonance imaging with a high-resolution three-dimensional T2 sequence. Data on the symptomatic side were compared with those on the asymptomatic side in patients and with the mean measurements of the bilateral sides in controls. Receiver operating characteristic (ROC) analysis was conducted to evaluate the performance of APR and ATN in distinguishing TN patients from controls. Results: In TN patients without NVC, the mean ± standard deviation (SD) of APR on the symptomatic side (98.40° ± 19.75°) was significantly smaller than that of the asymptomatic side (105.59° ± 22.45°, p = 0.019) and controls (108.44° ± 15.98°, p = 0.003). The mean ATN ± SD on the symptomatic side (144.41° ± 8.92°) was significantly smaller than that of the asymptomatic side (149.67° ± 8.09°, p = 0.003) and controls (150.45° ± 8.48°, p = 0.001). The area under the ROC curve for distinguishing TN patients from controls was 0.673 (95% confidence interval [CI]: 0.579-0.758) for APR and 0.700 (CI: 0.607-0.782) for ATN. The sensitivity and specificity using the diagnostic cutoff yielding the highest Youden index were 81.8% (54/66) and 49.1% (28/57), respectively, for APR (with a cutoff score of 94.30°) and 65.2% (43/66) and 66.7% (38/57), respectively, for ATN (cutoff score, 148.25°). Conclusion: In patients with TN without NVC, APR and ATN were smaller than those in controls, which may explain the potential cause of TN and provide additional information for diagnosis.

Study on bearing capacity of combined confined concrete arch in large-section tunnel

  • Jiang Bei;Xu Shuo;Wang Qi;Xin Zhong Xin;Wei Hua Yong;Ma Feng Lin
    • Steel and Composite Structures
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    • v.51 no.2
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    • pp.117-126
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    • 2024
  • There are many challenges in the construction of large-section tunnels, such as extremely soft rock and fractured zones. In order to solve these problems, the confined concrete support technology is proposed to control the surrounding rocks. The large-scale laboratory test is carried out to clarify mechanical behaviours of the combined confined concrete and traditional I-steel arches. The test results show that the bearing capacity of combined confined concrete arch is 3217.5 kN, which is 3.12 times that of the combined I-steel arch. The optimum design method is proposed to select reasonable design parameters for confined concrete arch. The parametric finite element (FE) analysis is carried out to study the effect of the design factors via optimum design method. The steel pipe wall thickness and the longitudinal connection ring spacing have a significant effect on the bearing capacity of the combined confined concrete arch. Based on the above research, the confined concrete support technology is applied on site. The field monitoring results shows that the arch has an excellent control effect on the surrounding rock deformation. The results of this research provide a reference for the support design of surrounding rocks in large-section tunnels.

Impact performance study of filled thin-walled tubes with PM-35 steel core

  • Kunlong Tian;Chao Zhao;Yi Zhou;Xingu Zhong;Xiong Peng;Qunyu Yang
    • Structural Engineering and Mechanics
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    • v.91 no.1
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    • pp.75-86
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    • 2024
  • In this paper, the porous metal PM-35 is proposed as the filler material of filled thin-walled tubes (FTTs), and a series of experimental study is conducted to investigate the dynamic behavior and energy absorption performance of PM-35 filled thin-walled tubes under impact loading. Firstly, cylinder solid specimens of PM-35 steel are tested to investigate the impact mechanical behavior by using the Split Hopkinson pressure bar set (SHP); Secondly, the filled thin-walled tube specimens with different geometric parameters are designed and tested to investigate the feasibility of PM-35 steel applied in FTTs by the orthogonal test. According to the results of this research, it is concluded that PM-35 steel is with the excellent characteristics of high energy absorption capacity and low yield strength, which make it a potential filler material for FTTs. The micron-sizes pore structure of PM-35 is the main reason for the macroscopic mechanical behavior of PM-35 steel under impact loading, which makes the material to exhibit greater deformation when subjected to external forces and obviously improve the toughness of the material. In addition, PM-35 steel core-filled thin-wall tube has excellent energy absorption ability under high-speed impact, which shows great application potential in the anti-collision structure facilities of high-speed railway and maglev train. The parameter V0 is most sensitive to the energy absorption of FTT specimens under impact loading, and the sensitivity order of different variations to the energy absorption is loading speed V0>D/t>D/L. The loading efficiency of the FTT is affected by its different geometry, which is mainly determined by the sleeve material and the filling material, which are not sensitive to changes in loading speed V0, D/t and D/L parameters.

Network pharmacology prediction to discover the potential pharmacological action mechanism of Rhizoma Dioscoreae for liver regeneration

  • Wei Liu;Wenyu Wang;Chenglong Tian;Ming-Zhong Sun;Shuqing Liu;Qinlong Liu
    • The Korean Journal of Physiology and Pharmacology
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    • v.28 no.5
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    • pp.479-491
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    • 2024
  • Improving liver regeneration (LR) remains a medical issue, and there is currently a lack of safe and effective drugs for LR. Rhizoma Dioscoreae (SanYak, SY) is a traditional Chinese medicine. However, the underlying action mechanism of SY treatment for LR is yet to be fully elucidated. To explore the mechanism by which SY affects LR, we have conducted a series of methods for network pharmacological analysis, molecular docking, and in vivo experimental validation in mice. Overall, 9 compounds and 30 predicted target genes of SY were found to be associated with the therapeutic effects of LR. Compared with the model group, hematoxylin and eosin staining revealed that the mice with preoperative drug intervention possessed fewer postoperative hepatocyte bubbles and relatively regular morphology. Furthermore, the serum alanine transaminase and aspartate aminotransferase levels were reduced, immunohistochemistry revealed elevated proliferating cell nuclear antigen positivity rate, and Western blotting demonstrated that the phospho-protein kinase B (AKT)/AKT ratio was downregulated and that vascular endothelial growth factor A (VEGFA) expression levels were upregulated. This study explored dioscin, the main active ingredient of SY, and its potential therapeutic effects on LR. It repairs damaged liver following surgery and promotes liver cell proliferation. The action mechanism comprises reducing AKT phosphorylation levels and upregulating VEGFA expression levels. Thus, this study provides a new direction for further research on the mechanism of SY promoting LR.

Establishing a Nomogram for Stage IA-IIB Cervical Cancer Patients after Complete Resection

  • Zhou, Hang;Li, Xiong;Zhang, Yuan;Jia, Yao;Hu, Ting;Yang, Ru;Huang, Ke-Cheng;Chen, Zhi-Lan;Wang, Shao-Shuai;Tang, Fang-Xu;Zhou, Jin;Chen, Yi-Le;Wu, Li;Han, Xiao-Bing;Lin, Zhong-Qiu;Lu, Xiao-Mei;Xing, Hui;Qu, Peng-Peng;Cai, Hong-Bing;Song, Xiao-Jie;Tian, Xiao-Yu;Zhang, Qing-Hua;Shen, Jian;Liu, Dan;Wang, Ze-Hua;Xu, Hong-Bing;Wang, Chang-Yu;Xi, Ling;Deng, Dong-Rui;Wang, Hui;Lv, Wei-Guo;Shen, Keng;Wang, Shi-Xuan;Xie, Xing;Cheng, Xiao-Dong;Ma, Ding;Li, Shuang
    • Asian Pacific Journal of Cancer Prevention
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    • v.16 no.9
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    • pp.3773-3777
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    • 2015
  • Background: This study aimed to establish a nomogram by combining clinicopathologic factors with overall survival of stage IA-IIB cervical cancer patients after complete resection with pelvic lymphadenectomy. Materials and Methods: This nomogram was based on a retrospective study on 1,563 stage IA-IIB cervical cancer patients who underwent complete resection and lymphadenectomy from 2002 to 2008. The nomogram was constructed based on multivariate analysis using Cox proportional hazard regression. The accuracy and discriminative ability of the nomogram were measured by concordance index (C-index) and calibration curve. Results: Multivariate analysis identified lymph node metastasis (LNM), lymph-vascular space invasion (LVSI), stromal invasion, parametrial invasion, tumor diameter and histology as independent prognostic factors associated with cervical cancer survival. These factors were selected for construction of the nomogram. The C-index of the nomogram was 0.71 (95% CI, 0.65 to 0.77), and calibration of the nomogram showed good agreement between the 5-year predicted survival and the actual observation. Conclusions: We developed a nomogram predicting 5-year overall survival of surgically treated stage IA-IIB cervical cancer patients. More comprehensive information that is provided by this nomogram could provide further insight into personalized therapy selection.

A Study on processing of medicinal on medical books of before Han(漢)dynasty (한대(漢代) 이전의 의적(醫籍)을 통한 '포제(炮制)'의 연구)

  • Kim, Sung-Cheol;Ha, Hong-Ki;Kim, Ki-Wook
    • Journal of Korean Medical classics
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    • v.24 no.4
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    • pp.157-174
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    • 2011
  • We derived following result by organizing research about processing of medicinal of before Han(漢) dynesty. The human being intake of natural substance for the purpose of treatment was what happened later than the use of natural substance as food. According to the record of by the early years of Shang(商) dynasty, we can assume that we cooked food with water and fire. The reason why there is no appearance of common production that can be included under the name of 'Tang Ye(湯液)' in the medical record discovered from Ma Wang Dui(馬王堆) is because 'Tang Ye' was yet developed. However, as the presentation of format of medicine process, there was gradual formation of medicinal fluid concept. There are quite of records on major details of cloth manufacture like washing and selection, grinding, processing of medicine from the recordings of "Wu Shi Er Bing Fang(五十二病方)", "Yang Sheng Fang(養生方)", "Za Liao Fang(雜療方)" discovered at Ma Wang Dui. It used words like 'Ze(擇)', 'Qu(去)' for the selection and 'Jiu(酒)', 'Zhuo(濯)' for the wash as a process method before cloth manufacture. When filter the processed medicine, it used words like 'Zhuo(捉)', 'Suo(索)', 'Jun(浚)' and used 'Yin Gan(陰乾)', 'Bao(暴)', 'Yang(暘)' for dry. The 'cutting(切削)' that crushes the medicine used different names based on the properties of medicines. The most frequent crush is 'Ye(冶)' and it means the powered medicine after dry. There was thermal process of mild fire(微火) and heating of 'Wen(溫)'. There are many states of medicine seen from the medical record discovered at Ma Wang Dui so they can be said as original medicine. 藥末劑 is relatively commercialized type then. Here, it includes later 湯劑 but there was no name such as 'decoction(湯)' or 'decoction of medical ingredients(湯液)'. Also, 'Fu Ju(㕮咀)' is the transformation of what was 'Fu Qie(父且)' at "Ja Liao Fang" of medical books of Ma Wang Dui with time flow. The original meaning of 'Fu Qie(父且)' is 'Fu Zu(斧俎)' and it means the crushing medicine with axe. The most important thing among the medical books of Han dynasty is "Shen Nong Ben Cao Jing(神農本草經)" and "Shang Han Za Bing Lun(傷寒雜病論)" of Zhang Zhong Jing(張仲景). "Shen Nong Ben Cao Jing" mentioned the dry method of medicine, collection and process production time, cooked and uncooked use of medicine and there are several types of medicine. Other than those, it mentioned 'Seven methods of combining herbs(七情合和)' to address cautions for combining medicines. Therefore, the 'processing of medicinal' in east Han dynasty period entered the theoretical step. However, there is only little recording on cloth manufacture of detailed medicine. From the "Shang Han Za Bing Lun" of Zhang Zhong Jing, the development in the way of 'processing of medicinal' reveled the cloth manufacture for each medicine. This tradition is continued until today and so it presents the development of purpose of 'processing of medicinal' is to greatly present the effect of medicine and to reduce the side-effect.

Effect of a Herb Mixture (HIM-I) on the Protection of the Hematopoietic-Immune System and Self-renewal Tissues against Radiation Damage (면역조혈계 및 재생조직의 방사선 손상에 대한 생약복합물(HIM-I)의 방호 효과)

  • Park, Hae-Ran;Kim, Sung-Ho;Yee, Sung-Tae;Byun, Myung-Woo;Jo, Sung-Kee
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.34 no.5
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    • pp.605-612
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    • 2005
  • In previous studies, we evaluated the effect of the 6 energy-tonic or blood-building prescriptions of traditional oriental medicine, and observed that Si-Wu-Tang and Bu-Zhong-Yi-Qi-Tang showed high activity in the protection of the gastrointestinal and hematopoietic organs in irradiated mice. But any of these prescriptions did not show a high activity in the activation of the immune cells. We performed this study to design an herb mixture which protects the self-renewal tissues and also promotes recovery of the immune system against radiation damage. In order to meet all the requirements, we designed a new mixture of 3 edible herbs listed in Korean Food Code. The mixture of Angelim gigas radix, Cnidium officinale rhizoma and Paeonia japonica radix was decocted with hot water, and the activities of the water extract (HIM-I) were evaluated. HIM-1 stimulated the immune cells in a much higher extent than the traditional prescriptions, and promoted dramatically the growth of bone marrow stem cells in vitro. Also, HIM-1 protected digestive and hematopoietic organs against radiation as effectively as the 2 prescriptions, Si-Wu-Tang and Bu-Zhong-Yi-Qi-Tang. On the other hand, it showed high in vitro antioxidative activity that might be considered as a mechanism of the protective effects against radiation. Although the detailed mechanisms of those effects remain to be elucidated, these results indicated that HIM-I might be a useful agent for protection and recovery of body from various risk factor as well as radiation, especially since it is a relatively nontoxic natural product.

A Study on the Reactionism Tendency in the Calligraphy Style of Changam(蒼巖) Lee Sam-man(李三晩) (창암(蒼巖) 이삼만(李三晩)의 서풍(書風)에 나타난 복고적 성향 고찰)

  • Park, Jae-bok
    • (The)Study of the Eastern Classic
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    • no.49
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    • pp.357-392
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    • 2012
  • An author is bound to reflect his or her own thinking and inclination in his or her works. The previous studies on Changam(蒼巖), however, mostly discussed the aesthetics in the forms of his introductions and works, hardly addressing his thinking reflected in his works. Recognizing that he had the "reactionism tendency" unlike the Bukhak-School(北學派), which was the cultural mainstream of the days, this study examined the specific patterns of the reactionism calligraphy style in his learning and calligraphy processes and works. He loved to write xing-cao-shu(行草書) with a focus on the materials written in one's own calligraphy, but he also emphasized that one should obtain the force of his or her calligraphy style by mastering kai shu before calligraphy xing cao shu. He thus left a lot of works in the xiao kai(小楷) of the Wang Xzhi(王羲之) calligraphy style throughout his life, which is attributed to the influences of the calligraphers of dong-guk-jin-che(東國眞體) in the latter half of Joseon(朝鮮) and those of Lee Gwang-sa(李匡師), his master in spirit. He is distinguished from the other calligraphers of the times in that he made lifelong efforts to compensate for the lacking stroke of the pen in the model calligraphy of Wang Xzhi. In the calligraphy theory, he put importance on the traditional method of Han-Wei(漢魏) and took Cai Yong(蔡邕) and Zhong Yao(鍾繇) as the fundamentals. For da kai(大楷), he constantly practiced the with the stroke of the pen by added to it, the letters of Wei(魏) Wudi(武帝), by Yan Zhenqing(顔眞卿), and letters of Kim Saeng(金生). His late works using the intended conception of and , in particular, present his unique calligraphy style that added the crooked forms of to the shapes of characters of that were in the kai-shu(楷書) style. It is a limitation that a considerable number of calligraphy materials Changam studied or consulted were either reprint copy or block book rather than original rubbing edition due to time and space restrictions. However, it is also true that those restrictions made an important contribution to his creation of his unique calligraphy style with deep local colors at the result of his constant efforts.