Effect of the TiO2 Nanoparticles on the Growth Behavior of Intermetallics in Sn/Cu Solder Joints

Shengyan Shang,Anil Kunwar,Jinye Yao,Yanfeng Wang,Haitao Ma,Yunpeng Wang 대한금속·재료학회 2019 METALS AND MATERIALS International Vol.25 No.2

In order to investigate the effect of TiO2 nanoparticles on growth behavior of interfacial Cu6Sn5 intermetallics compounds(IMCs) in Pb-free Sn/Cu system, the solder joints are fabricated by using flux doped with different content (0.0–2.0 wt% offlux) and particle diameter (5 nm and 50 nm) of TiO2 . In context of isothermal reflow soldering at 250 °C and subsequentair cooling, the increase in reflow duration from 10 to 120 s was characterized with an increment in IMC layer thicknessand grain size, due to the enhancement of Cu flux contribution for Ostwald ripening during constant temperature reflow andprecipitation kinetics during cooling. The increased proportion of TiO2 nanoparticles in flux was found to reduce the growthof IMC layer and grain size. The suppression effect on IMC was more pronounced for 5 nm particles as compared to the 50nm TiO2 . The TiO2 nanoparticles, adsorbed on IMC plane can retard the growth of the latter. Presence of sufficient amountof a given sized TiO2 nanoparticles among IMCs, by increasing the effective stress at the localized interfaces, and causingthe breaking of brittle Cu6Sn5 during growth stage; can help in the inhibition of IMC whisker formation. Particle diameterand mass proportion of TiO2 nanoparticles are important for soldering materials design.

A Method of Threat Evaluation for Mobile Network

Wang Bailing,Li Shang,Qu Yun,Wang Xiaopeng,Liu Yang 보안공학연구지원센터 2013 International Journal of Security and Its Applicat Vol.7 No.3

Characteristics and source apportionment of fine haze aerosol in Beijing during the winter of 2013

Shang, Xiaona,Zhang, Kai,Meng, Fan,Wang, Shihao,Lee, Meehye,Suh, Inseon,Kim, Daigon,Jeon, Kwonho,Park, Hyunju,Wang, Xuezhong,Zhao, Yuxi Copernicus GmbH 2018 Atmospheric Chemistry and Physics Vol.18 No.4

<P>Abstract. For PM2.5 filter samples collected daily at the Chinese Research Academy of Environmental Sciences (Beijing, China) from December of 2013 to February of 2014 (the winter period), chemical characteristics and sources were investigated with an emphasis on haze events in different alert levels. During the 3 months, the average PM2.5 concentration was 89 µg m−3, exceeding the Chinese national standard of 75 µg m−3 in 24 h. The maximum PM2.5 concentration was 307 µg m−3, which characterizes developed-type pollution (PM2.5 / PM10>0.5) in the World Health Organization criteria. PM2.5 was dominated by SO42−, NO3−, and pseudo-carbonaceous compounds with obvious differences in concentrations and proportions between non-haze and haze episodes. The non-negative matrix factorization (NMF) analysis provided reasonable PM2.5 source profiles, by which five sources were identified: soil dust, traffic emission, biomass combustion, industrial emission, and coal combustion accounting for 13, 22, 12, 28, and 25 % of the total, respectively. The dust impact increased with northwesterlies during non-haze periods and decreased under stagnant conditions during haze periods. A blue alert of heavy air pollution was characterized by the greatest contribution from industrial emissions (61 %). During the Chinese Lantern Festival, an orange alert was issued and biomass combustion was found to be the major source owing to firework explosions. Red-alert haze was almost equally contributed by local traffic and transported coal combustion emissions from the vicinity of Beijing (approximately 40 % each) that was distinguished by the highest levels of NO3− and SO42−, respectively. This study also reveals that the severity and source of haze are largely dependent on meteorological conditions. </P>

Effect of P3HT passivation layer on triple cation organic-inorganic hybrid perovskite memristor

Wang Yucheng,Xiong Yuxuan,Wang Hongsu,Wu Xiang,Sha Jian,Shang Yueyang,Zhang Yongqi,Li Wei,Wang Shaoxi 한국물리학회 2023 Current Applied Physics Vol.47 No.-

Triple cation organic-inorganic hybrid perovskite (TCP) memristor is a novel candidate for artificial visual applications due to the integrating of recognition, storage, and computing. However, concerns remain regarding the moisture-induced degradation and thermal stability. Here, P3HT was deposited on the TCP film to optimize the memristor performance which showed better film surface quality and lower power consumption. When the thickness of the P3HT layer increases, the grain boundary of the TCP film was gradually filled, leading to the inhibition of the ions/vacancies drifting, and thus the device type was changed from digital to analog. Besides, various functions are demonstrated in TCP photoelectric memristor including excitatory postsynaptic current under optic and electric stimulations and spike rate-dependent plasticity, proving the great application prospects in numerical calculation and information perception.

Rapid Detection of Streptococcus mutans Using an Integrated Microfluidic System with Loop-Mediated Isothermal Amplification

Wang Jingfu,Wang Jingyi,Chang Xin,Shang Jin,Wang Yuehui,Ma Qin,Shen Liangliang 한국미생물·생명공학회 2023 Journal of microbiology and biotechnology Vol.33 No.8

Streptococcus mutans is the primary causative agent of caries, which is one of the most common human diseases. Thus, rapid and early detection of cariogenic bacteria is critical for its prevention. This study investigated the combination of loop-mediated isothermal amplification (LAMP) and microfluid technology to quantitatively detect S. mutans. A low-cost, rapid microfluidic chip using LAMP technology was developed to amplify and detect bacteria at 2.2–2.2 × 106 colony-forming units (CFU)/ml and its detection limits were compared to those of standard polymerase chain reaction. A visualization system was established to quantitatively determine the experimental results, and a functional relationship between the bacterial concentration and quantitative results was established. The detection limit of S. mutans using this microfluidic chip was 2.2 CFU/ml, which was lower than that of the standard approach. After quantification, the experimental results showed a good linear relationship with the concentration of S. mutans, thereby confirming the effectiveness and accuracy of the custom-made integrated LAMP microfluidic system for the detection of S. mutans. The microfluidic system described herein may represent a promising simple detection method for the specific and rapid testing of individuals at risk of caries.

Life Cycle of Dermacentor everestianus Hirst, 1926 (Acari: Ixodidae) under Laboratory Conditions

Shang Jin,Tianhong Wang,Tuo Li,Ming Liu,Qingying Jia,Xiaolong Yang,Hui Wang,Zhijun Yu,Jingze Liu 대한기생충학열대의학회 2017 The Korean Journal of Parasitology Vol.55 No.2

Upregulation of MicroRNA-34a Sensitizes Ovarian Cancer Cells to Resveratrol by Targeting Bcl-2

Shangli Yao,Ming Gao,Zujun Wang,Wenyan Wang,Lei Zhan,Bing Wei 연세대학교의과대학 2021 Yonsei medical journal Vol.62 No.8

Purpose: Resveratrol (REV), a natural compound found in red wine, exhibits antitumor activity in various cancers, includingovarian cancer (OC). However, its potential anti-tumor mechanisms in OC are not well characterized. Here, we tried to elucidatethe underlying mechanisms of REV in OC cells. Materials and Methods: The anti-proliferative effects of REV against OC cells were measured using CCK-8 assay. Apoptosis wasmeasured using an Annexin V-FITC/PI apoptosis detection kit. The anti-metastasis effects of REV were evaluated by invasion assayand wound healing assay. The miRNA profiles in REV-treated cells were determined by microarray assay. Results: Our results showed that REV treatment suppresses the proliferation, induces the apoptosis, and inhibits the invasion andmigration of OV-90 and SKOV-3 cells. miR-34a was selected for further study due to its tumor suppressive roles in various humancancers. We found miR-34a overexpression enhanced the inhibitory effects of REV on OC cells, whereas miR-34a inhibition hadthe opposite effect in OC cells. In addition, we verified that BCL2, an anti-apoptotic gene, was found directly targeted by miR-34a. We also found that REV reduced the expression of Bcl-2 in OC cells. Further investigations revealed that overexpression of Bcl-2significantly abolished the anti-tumor effects of REV on OC cells. Conclusion: Overall, these results demonstrated that REV exerts anti-cancer effects on OC cells through an miR-34a/Bcl-2 axis,highlighting the therapeutic potential of REV for treatment of OC.

The effect of Zn(2+) on Pelodiscus sinensis creatine kinase: unfolding and aggregation studies.

Wang, Su-Fang,Lee, Jinhyuk,Wang, Wei,Si, Yue-Xiu,Li, Caiyan,Kim, Tae-Rae,Yang, Jun-Mo,Yin, Shang-Jun,Qian, Guo-Ying Adenine Press 2013 Journal of biomolecular structure & dynamics Vol.31 No.6

<P>We studied the effects of Zn(2+) on creatine kinase from the Chinese soft-shelled turtle, Pelodiscus sinensis (PSCK). Zn(2+) inactivated the activity of PSCK (IC(50)?=?.079??.004?mM) following first-order kinetics consistent with multiple phases. The spectrofluorimetry results showed that Zn(2+) induced significant tertiary structural changes of PSCK with exposure to hydrophobic surfaces and that Zn(2+) directly induced PSCK aggregation. The addition of osmolytes such as glycine, proline, and liquaemin successfully blocked PSCK aggregation, recovering the conformation and activity of PSCK. We measured the ORF gene sequence of PSCK by rapid amplification of cDNA end and simulated the 3D structure of PSCK. The results of molecular dynamics simulations showed that eight Zn(2+) bind to PSCK and one Zn(2+) is predicted to bind in a plausible active site of creatine and ATP. The interaction of Zn(2+) with the active site could mostly block the activity of PSCK. Our study provides important insight into the action of Zn(2+) on PSCK as well as more insights into the PSCK folding and ligand-binding mechanisms, which could provide important insight into the metabolic enzymes of P. sinensis.</P>

Management of Gallstones and Acute Cholecystitis in Patients with Liver Cirrhosis: What Should We Consider When Performing Surgery?

( Shang Yu Wang ),( Chun Nan Yeh ),( Yi Yin Jan ),( Miin Fu Chen ) 대한소화기기능성질환·운동학회(구 대한소화관운동학회) 2021 Gut and Liver Vol.15 No.4

Acute cholecystitis and several gallbladder stone-related conditions, such as impacted common bile duct stones, cholangitis, and biliary pancreatitis, are common medical conditions in daily practice. An early cholecystectomy or drainage procedure with delayed cholecystectomy is the current standard of treatment based on published clinical guidelines. Cirrhosis is not only a condition of chronically impaired hepatic function but also has systemic effects in patients. In cirrhotic individuals, several predisposing factors, including changes in the bile acid composition, increased nucleation of bile, and decreased motility of the gallbladder, contribute to the formation of biliary stones and the possibility of symptomatic cholelithiasis, which is an indication for surgical treatment. In addition to these predisposing factors for cholelithiasis, systemic effects and local anatomic consequences related to cirrhosis lead to anesthesiologic risks and perioperative complications in cirrhotic patients. Therefore, the treatment of the aforementioned biliary conditions in cirrhotic patients has become a challenging issue. In this review, we focus on cholecystectomy for cirrhotic patients and summarize the surgical indications, risk stratification, surgical procedures, and surgical outcomes specific to cirrhotic patients with symptomatic cholelithiasis. (Gut Liver 2021;15:517-527)

The effect of thiobarbituric acid on tyrosinase: inhibition kinetics and computational simulation.

Yin, Shang-Jun,Si, Yue-Xiu,Wang, Zhi-Jiang,Wang, Su-Fang,Oh, Sangho,Lee, Sanghyuk,Sim, Seon-Mi,Yang, Jun-Mo,Qian, Guo-Ying,Lee, Jinhyuk,Park, Yong-Doo Adenine Press 2011 Journal of biomolecular structure & dynamics Vol.29 No.3

<P>Tyrosinase plays various roles in organisms and much research has focused on the regulation of tyrosinase activity. We studied the inhibitory effect of thiobarbituric acid (TBA) on tyrosinase. Our kinetic study showed that TBA inhibited tyrosinase in a reversible noncompetitive manner (K(i) 5 14.0 ± 8.5 mM and IC?????? 5 8.0 ± 1.0 mM). Intrinsic and ANS-binding fluorescences studies were also performed to gain more information regarding the binding mechanism. The results showed that no tertiary structural changes were obviously observed. For further insight, we predicted the 3D structure of tyrosinase and simulated the docking between tyrosinase and TBA. The docking simulation was successful with significant scores (binding energy for AutoDock4: -5.52 kcal/mol) and suggested that TBA was located in the active site. The 11 ns molecular dynamics simulation convinced that the four HIS residues (residue numbers: 57, 90, 250, and 282) were commonly responsible for the interaction with TBA. Our results provide a new inhibition strategy that works using an antioxidant rather than targeting the copper ions within the tyrosinase active site.</P>