Investigation on Properties of Rock Joint in Compression Dynamic Test

Nan Wu,Cong Zhang,Semaierjiang Maimaitiyusupu,Zhen-de Zhu 대한토목학회 2019 KSCE JOURNAL OF CIVIL ENGINEERING Vol.23 No.9

This paper is devoted to investigate rock joint interaction with stress waves by split Hopkinson pressure bar (SHPB) during wave propagation on dynamic loading. Taking two different specimens from the intact specimen (Series N) and the joint specimen (Series J),this study focused on three aspects: the influence of joint specimens on waveform propagation, inversion analysis of rock joint parameters using the waveform transmission coefficient, and the influence of the joint on rock specimens. With an increase in impact air pressure, compared with the intact sample, the transmittance and reflectance of joint specimens showed the opposite change rule; the closure rate change process of rock joint was converted from an exponential function to a linear function; the peak strength of the intact specimens was higher than the joint specimens at the same impact pressure above 19.58%, 21.21%, 21.56%, and 22.68% (mean values), respectively; and the strain rates (mean value) of the intact specimens were respectively 1.61, 1.31, 1.20, and 1.09 times that of the joint specimens.

Alpha-Ketoglutarate: Physiological Functions and Applications

Wu, Nan,Yang, Mingyao,Gaur, Uma,Xu, Huailiang,Yao, Yongfang,Li, Diyan The Korean Society of Applied Pharmacology 2016 Biomolecules & Therapeutics(구 응용약물학회지) Vol.24 No.1

Alpha-ketoglutarate (AKG) is a key molecule in the Krebs cycle determining the overall rate of the citric acid cycle of the organism. It is a nitrogen scavenger and a source of glutamate and glutamine that stimulates protein synthesis and inhibits protein degradation in muscles. AKG as a precursor of glutamate and glutamine is a central metabolic fuel for cells of the gastrointestinal tract as well. AKG can decrease protein catabolism and increase protein synthesis to enhance bone tissue formation in the skeletal muscles and can be used in clinical applications. In addition to these health benefits, a recent study has shown that AKG can extend the lifespan of adult Caenorhabditis elegans by inhibiting ATP synthase and TOR. AKG not only extends lifespan, but also delays age-related disease. In this review, we will summarize the advances in AKG research field, in the content of its physiological functions and applications.

Review : Alpha-Ketoglutarate: Physiological Functions and Applications

( Nan Wu ),( Mingyao Yang ),( Uma Gaur ),( Huailiang Xu ),( Yongfang Yao ),( Diyan Li ) 한국응용약물학회 2016 Biomolecules & Therapeutics(구 응용약물학회지) Vol.24 No.1

Alpha-ketoglutarate (AKG) is a key molecule in the Krebs cycle determining the overall rate of the citric acid cycle of the organism. It is a nitrogen scavenger and a source of glutamate and glutamine that stimulates protein synthesis and inhibits protein degradation in muscles. AKG as a precursor of glutamate and glutamine is a central metabolic fuel for cells of the gastrointestinal tract as well. AKG can decrease protein catabolism and increase protein synthesis to enhance bone tissue formation in the skeletal muscles and can be used in clinical applications. In addition to these health benefits, a recent study has shown that AKG can extend the lifespan of adult Caenorhabditis elegans by inhibiting ATP synthase and TOR. AKG not only extends lifespan, but also delays age-related disease. In this review, we will summarize the advances in AKG research field, in the content of its physiological functions and applications.

Development of a Pants Pattern for Chinese Women in Their 20s Using a Virtual Fitting Method

( Nan Wu ),( Chuyeon Suh ) 한국의류학회 2021 한국의류학회지 Vol.45 No.6

This study was conducted to develop a basic pants pattern reflecting the average body shape of Chinese women in their 20s by using a virtual fitting method. A formula for the research pattern was derived by applying the measured value based on the drafting method of existing patterns. The final pattern was presented through two actual fitting processes. The suitability of the final pattern was then verified through a functional evaluation and an appearance evaluation based on an actual fitting and a virtual fitting. As a result of the evaluations, the final pattern reflected the body shape of Chinese women in their 20s and was evaluated as a higher quality pattern compared to existing patterns. The final pattern was based on the omphalion waist circumference. Ease amounts were set to be the omphalion waist circumference + 1.0 cm, hip circumference + 2.0 cm, and the pants length was set to 94 cm.

Dynamic Behavior of Rock Joint Under Different Impact Loads

Nan Wu,Zhen-de Zhu,Cong Zhang,Zhihua Luo 대한토목학회 2019 KSCE JOURNAL OF CIVIL ENGINEERING Vol.23 No.2

In order to investigate the influence of the rock joint to rock mass on dynamic loading, the Split Hopkinson Pressure Bar (SHPB) apparatus is used as an effective instrument. Using three different samples of intact (Series A), unfilled joint (Series B), and filled joint (Series C) interfaces, impact tests were performed under different impact speeds. Results showed that the peak strength of series B and C was 55%–75% that of series A. Series C was 10%–20% lower than series B because the former was filled with gypsum in the interface. The attenuation law of the transmission coefficient and failure mode caused by the rock joint was also obtained. To address the problem of classic rock joint constitutive relations being unsuitable under dynamic loading, a new regular expression is proposed by defining two velocity impact factors at respective impact velocities of 3.6 m/s, 6.6 m/s, and 9.6 m/s. Calculation results of this function are tested and verified, and the data are highly consistent.

HAYMAN T DIRECTIONS OF MEROMORPHIC FUNCTIONS IN SOME ANGULAR DOMAINS

Wu, Nan,Xuan, Zu-Xing Korean Mathematical Society 2015 대한수학회보 Vol.52 No.1

This paper is devoted to investigate the singular directions of meromorphic functions in some angular domains. We will confirm the existence of Hayman T directions in some angular domains. This is a continuous work of Yang [8] and Zheng [10].

On the growth of solutions to linear complex differential equations on annuli

Nan Wu,Zu-Xing Xuan 대한수학회 2019 대한수학회보 Vol.56 No.2

In this note, we consider the growth of solutions to second order and higher order linear complex differential equations on annuli instead of the complex plane. We establish several theorems that are analogues of the results in the complex plane.

Stem Cell-Derived Exosomes: A New Method for Reversing Skin Aging

Wu Jinyan,Wu Sai-Nan,Zhang Li-Ping,Zhao Xiansheng,Li Yue,Yang Quyang,Yuan Ruoyue,Liu Jian-Lan,Mao Hong-Ju,Zhu Ningwen 한국조직공학과 재생의학회 2022 조직공학과 재생의학 Vol.19 No.5

Senescence is an inevitable natural life process that involves structural and functional degeneration of tissues and organs. Recently, the process of skin aging has attracted much attention. Determining a means to delay or even reverse skin aging has become a research hotspot in medical cosmetology and anti-aging. Dysfunction in the epidermis and fibroblasts and changes in the composition and content of the extracellular matrix are common pathophysiological manifestations of skin aging. Reactive oxygen species and matrix metalloproteinases play essential roles in this process. Stem cells are pluripotent cells that possess self-replication abilities and can differentiate into multiple functional cells under certain conditions. These cells also possess a strong ability to facilitate tissue repair and regeneration. Stem cell transplantation has the potential for application in anti-aging therapy. Increasing studies have demonstrated that stem cells perform functions through paracrine processes, particularly those involving exosomes. Exosomes are nano-vesicular substances secreted by stem cells that participate in cell-to-cell communication by transporting their contents into target cells. In this chapter, the biological characteristics of exosomes were reviewed, including their effects on extracellular matrix formation, epidermal cell function, fibroblast function and antioxidation. Exosomes derived from stem cells may provide a new means to reverse skin aging.

Chinese Urologists’ Views of Practice Patterns in the Diagnosis and Treatment of Benign Prostatic Hyperplasia: A Nationwide Survey

Nan Wu,Jian Sun,Pulin Yu,Zhenqiu Sun 대한배뇨장애요실금학회 2012 International Neurourology Journal Vol.16 No.4

Purpose: To assess the compliance of Chinese urologists with China’s benign prostatic hyperplasia (BPH) clinical practice guideline and to explore the diagnosis and therapy modalities for geriatric patients with BPH. Methods: A cross-sectional survey study was carried out in 33 medical centers in 11 different cities in China. A total of 190 urologists participated in a survey to record their preferences for diagnostic tests and treatment options for BPH outpatients. Diagnostic test results as well as health care demands were collected by surveying 2,027 outpatients aged 60 years and older. Results: The survey response rate was 97.4%. The respondents generally used the diagnostic tests recommended in China’s BPH clinical practice guideline at varying rates. The used rates for medical history, ultrasonography, and urinalysis were above 90.0%; that for uroflowmetry was 31.2%. In addition, the rate of use of recommended tests was higher among doctors in the north than among those in the south. Combination therapy with α-adrenoceptor antagonists and 5α-reductase inhibitors was the preferred treatment option for BPH, and was increasingly used with worsening lower urinary tract symptoms. Finasteride was the most prescribed medication (48.0%), followed by tamsulosin (22.7%). Conclusions: This study assessed the preferences of urologists in the diagnosis and treatment of BPH, which will serve as an important reference for updating and improving China’s current BPH clinical practice guideline.

HAYMAN T DIRECTIONS OF MEROMORPHIC FUNCTIONS IN SOME ANGULAR DOMAINS

Nan Wu,Zu-Xing Xuan 대한수학회 2015 대한수학회보 Vol.52 No.1

This paper is devoted to investigate the singular directions of meromorphic functions in some angular domains. We will confirm the existence of Hayman T directions in some angular domains. This is a continuous work of Yang [8] and Zheng [10].