Anti-Wear and Friction Properties of Nanoparticles as Additives in the Lithium Grease

Ho Chang,Chou-Wei Lan,Chih-Hao Chen,Mu-Jung Kao,Jia-Bin Guo 한국정밀공학회 2014 International Journal of Precision Engineering and Vol. No.

TiO2/CuO nano-particles were dispersed into lithium grease to improve the lubricating properties of the greases. Then, the processof sliding friction was tested. The friction force of the contact interface between a ball and a flat surface with TiO2/CuO nano-greasewas measured for a ball on a flat sliding wear tester. The worn surface was examined by a surface roughness tester and scanningelectron microscopy (SEM). The tested lithium grease was synthesized with 0.5wt.%, 1.0wt.%, 1.5wt.% and 2.0wt.% TiO2/CuO nanoparticles. Results indicate that the TiO2/CuO nano-particle additives can improve the wear resistance of lithium grease and decreasethe friction coefficient. In addition, the results show that a 1.0 wt% content of TiO2 nano-particles is the most efficient in reducingfriction and wear, and can significantly reduce the friction coefficient of the rubbing interface by about 40%, according to the frictiontests. The wear of the lithium grease with a 2.0wt.% content of CuO nano-particles added can reduce wear about by 60% incomparison with lithium grease. Furthermore, the SEM analysis results demonstrate that the addition of tribo-film forms and TiO2/CuO nano-particles on the worn surface is responsible for the decrease in friction and wear.

Intra-Arterial Treatment in Patients with Acute Massive Gastrointestinal Bleeding after Endoscopic Failure: Comparisons between Positive versus Negative Contrast Extravasation Groups

Wei-Chou Chang,Chang-Hsien Liu,Hsian-He Hsu,Guo-Shu Huang,Ho-Jui Tung,Tsai-Yuan Hsieh,Shih-Hung Tsai,Chung-Bao Hsieh,Chih-Yung Yu 대한영상의학회 2011 Korean Journal of Radiology Vol.12 No.5

Objective: To determine whether treatment outcome is associated with visualization of contrast extravasation in patients with acute massive gastrointestinal bleeding after endoscopic failure. Materials and Methods: From January 2007 to December 2009, patients that experienced a first attack of acute gastrointestinal bleeding after failure of initial endoscopy were referred to our interventional department for intra-arterial treatment. We enrolled 79 patients and divided them into two groups: positive and negative extravasation. For positive extravasation, patients were treated by coil embolization; and in negative extravasation, patients were treated with intra-arterial vasopressin infusion. The two groups were compared for clinical parameters, hemodynamics, laboratory findings, endoscopic characteristics, and mortality rates. Results: Forty-eight patients had detectable contrast extravasation (positive extravasation), while 31 patients did not (negative extravasation). Fifty-six patients survived from this bleeding episode (overall clinical success rate, 71%). An elevation of hemoglobin level was observed in the both two groups; significantly greater in the positive extravasation group compared to the negative extravasation group. Although these patients were all at high risk of dying, the 90-day mortality rate was significantly lower in the positive extravasation than in the negative extravasation (20% versus 42%, p < 0.05). A multivariate analysis suggested that successful hemostasis (odds ratio [OR] = 28.66) is the most important predictor affecting the mortality in the two groups of patients. Conclusion: Visualization of contrast extravasation on angiography usually can target the bleeding artery directly, resulting in a higher success rate to control of hemorrhage. Objective: To determine whether treatment outcome is associated with visualization of contrast extravasation in patients with acute massive gastrointestinal bleeding after endoscopic failure. Materials and Methods: From January 2007 to December 2009, patients that experienced a first attack of acute gastrointestinal bleeding after failure of initial endoscopy were referred to our interventional department for intra-arterial treatment. We enrolled 79 patients and divided them into two groups: positive and negative extravasation. For positive extravasation, patients were treated by coil embolization; and in negative extravasation, patients were treated with intra-arterial vasopressin infusion. The two groups were compared for clinical parameters, hemodynamics, laboratory findings, endoscopic characteristics, and mortality rates. Results: Forty-eight patients had detectable contrast extravasation (positive extravasation), while 31 patients did not (negative extravasation). Fifty-six patients survived from this bleeding episode (overall clinical success rate, 71%). An elevation of hemoglobin level was observed in the both two groups; significantly greater in the positive extravasation group compared to the negative extravasation group. Although these patients were all at high risk of dying, the 90-day mortality rate was significantly lower in the positive extravasation than in the negative extravasation (20% versus 42%, p < 0.05). A multivariate analysis suggested that successful hemostasis (odds ratio [OR] = 28.66) is the most important predictor affecting the mortality in the two groups of patients. Conclusion: Visualization of contrast extravasation on angiography usually can target the bleeding artery directly, resulting in a higher success rate to control of hemorrhage.

Using Multidetector-Row CT for the Diagnosis of Afferent Loop Syndrome Following Gastroenterostomy Reconstruction

Yu-Hsiu Juan,Wei-Chou Chang,Chih-Yung Yu,Hsian-He Hsu,Guo-Shu Huang,De-Chuan Chan,Chang-Hsien Liu,Ho-Jui Tung 연세대학교의과대학 2011 Yonsei medical journal Vol.52 No.4

Purpose: To assess the clinical manifestations and multidetector-row computed tomography (MDCT) findings of afferent loop syndrome (ALS) and to determine the role of MDCT on treatment decisions. Materials and Methods: From January 2004 to December 2008, 1,100 patients had undergone gastroenterostomy reconstruction in our institution. Of these, 22 (2%) patients were diagnosed as ALS after surgery that included Roux-en-Y gastroenterotomy (n=9), Billroth-II gastrojejunostomy (n=7), and Whipple’s operation (n=6). Clinical manifestations and MDCT features of these patients were recorded and statistically analyzed. The presumed etiologies of obstruction shown on the MDCT were correlated with clinical information and confirmed by surgery or endoscopic biopsy. Results: The most common clinical symptom was acute abdominal pain, presenting in 18 patients (82%). We found that a fluid-filled C-shaped afferent loop in combination with valvulae conniventes projecting into the lumen was the most common MDCT features of ALS. Malignant causes of ALS, such as local recurrence and carcinomatosis, are the most common etiologies of obstruction. These etiologies and associated complications can be predicted 100% by MDCT. Conclusion: Our results suggest that MDCT is a reliable modality for assessing the etiologies of ALS and guiding treatment decisions.

Discontinuation Rate of Newly Prescribed Donepezil in Alzheimer's Disease Patients in Asia

박기형,양영순,Chen Christopher,심용수,Domingueze Jacqueline C.,이찬녕,강경훈,김희진,정슬기,정지향,Hong Zhen,윤수진,Zhang Zhen-Xin,김은주,장재원,Li Yansheng,Xu Yun,Lin Yu-Te,Qu Qiumin,Hu Chaur-Jong,Chou Chih-Ho,Fan Dongsheng,Kandiah N 대한신경과학회 2021 Journal of Clinical Neurology Vol.17 No.3

Background and Purpose The rate of donepezil discontinuation and the underlying reasons for discontinuation in Asian patients with Alzheimer’s disease (AD) are currently unknown. We aimed to determine the treatment discontinuation rates in AD patients who had newly been prescribed donepezil in routine clinical practice in Asia. Methods This 1-year observational study involved 38 institutions in seven Asian countries, and it evaluated 398 participants aged 50–90 years with a diagnosis of probable AD and on newly prescribed donepezil monotherapy. The primary endpoint was the rate of donepezil discontinuation over 1 year. Secondary endpoints included the reason for discontinuation, treatment duration, changes in cognitive function over the 1-year study period, and compliance as assessed using a clinician rating scale (CRS) and visual analog scale (VAS). Results Donepezil was discontinued in 83 (20.9%) patients, most commonly due to an adverse event (43.4%). The mean treatment duration was 103.67 days in patients who discontinued. Among patients whose cognitive function was assessed at baseline and 1 year, there were no significant changes in scores on the Mini-Mental State Examination, Montreal Cognitive Assessment, and Trail-Making Test–Black and White scores, whereas the Clinical Dementia Rating score increased significantly (p<0.001). Treatment compliance at 1 year was 96.8% (306/316) on the CRS and 92.6±14.1% (mean±standard deviation) on the VAS. Conclusions In patients on newly prescribed donepezil, the primary reason for discontinuation was an adverse event. Cognitive assessments revealed no significant worsening at 1 year, indicating that continuous donepezil treatment contributes to the maintenance of cognitive function.