393 results on '"Jianfeng Shen"'
Search Results
302. Facile in situ synthesis of hydrophilic RGO-CD-Ag supramolecular hybrid and its enhanced antibacterial properties
- Author
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Mingxin Ye, Tie Li, Jianfeng Shen, and Na Li
- Subjects
Materials science ,Silver ,Surface Properties ,Supramolecular chemistry ,Metal Nanoparticles ,Bioengineering ,Gram-Positive Bacteria ,Spectrum Analysis, Raman ,law.invention ,Nanocomposites ,Biomaterials ,Contact angle ,law ,Gram-Negative Bacteria ,Spectroscopy, Fourier Transform Infrared ,Organic chemistry ,Molecule ,Aqueous solution ,Nanocomposite ,Graphene ,beta-Cyclodextrins ,Anti-Bacterial Agents ,Chemical engineering ,Mechanics of Materials ,Graphite ,Antibacterial activity ,Linker ,Hydrophobic and Hydrophilic Interactions - Abstract
In this study, a novel hydrophilic RGO–CD–Ag hybrid with the supramolecular β-cyclodextrin (CD) as a conjugation interface was fabricated successfully by a facile in situ synthesis process. The results of several characterizations confirmed that the in situ reaction provided a straightforward approach to deposit the CD wrapped Ag nanoparticles onto the CD chemical functionalized RGO sheets through the head-to-head H-bond interactions between the linker CD molecules. Moreover, it was also found that the CD interface that existed indeed influences the structure and performances of RGO–CD–Ag nanocomposite. The analysis of the static contact angle revealed that the surface property of the hybrid could be transformed from hydrophobic to hydrophilic feature, which highly improved the aqueous dispersibility. And then, the bactericidal test of RGO–CD–Ag was demonstrated and clearly showed the strongest antibacterial activity against Gram-negative and Gram-positive bacteria among all samples. In short, this method may readily provide a new family of supramolecular based materials expected to find applications beyond the bactericidal field.
- Published
- 2013
303. [Building and application of hospital's electronic film system]
- Author
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Kanmin, Yao, Kemin, Chen, Zilai, Pan, Zhian, Bai, Jianfeng, Shen, Haipeng, Dong, and Yue, Zhao
- Subjects
Radiology Information Systems ,Medical Records Systems, Computerized ,X-Ray Film - Abstract
This paper describes the design process and implementation process of electronic film system. The establishment of electronic film system allowed us to aggressively reduce film use and costs and to demonstrate a positive return.
- Published
- 2013
304. The modified model for pyrolysis of cylindrical wood
- Author
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Xinzhi Liu, Jianfeng Shen, Bin Li, Shuguang Zhu, and Houlei Zhang
- Subjects
Chemical engineering ,Chemistry ,Organic chemistry ,Pyrolysis - Published
- 2013
305. The modified model for predicting the products distribution in pyrolysis of biomass
- Author
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Shuguang Zhu, Jianfeng Shen, Xinzhi Liu, Houlei Zhang, and Bin Li
- Subjects
Distribution (number theory) ,Waste management ,Environmental science ,Biomass ,Pulp and paper industry ,Pyrolysis - Published
- 2013
306. [The value of electronic film for improving the quality of hospital services]
- Author
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Kanmin, Yao, Kemin, Chen, Zilai, Pan, Jianfeng, Shen, Haipeng, Dong, and Yue, Zhao
- Subjects
Diagnostic Imaging ,Quality Assurance, Health Care ,Surveys and Questionnaires ,X-Ray Film ,Hospital Information Systems - Abstract
In this paper, by describing and comparing different implementations of electronic film combined with the actual application of the electronic film in the imaging department and the clinical departments. We elaborate electronic film for optimizing the imaging department workflow to improve service quality and patient satisfaction and other aspects of value.
- Published
- 2013
307. U.S. Class Action Lawsuits Targeting Foreign Firms: The Spill-Over Effect
- Author
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Yixuan Rui, Xuxing Huang, Jianfeng Shen, and Gloria Y. Tian
- Subjects
Finance ,Price reaction ,Shareholder ,Spillover effect ,business.industry ,Issuer ,Monetary economics ,business ,Class action ,Litigation risk analysis - Abstract
We find negative price reactions among non-sued U.S.-listed foreign firms to filings of U.S. shareholder lawsuits targeting foreign issuers. This spillover effect is stronger among non-sued firms from the sued-company’s home country or industry, especially when the home country is poorly governed or the industry is litigation-prone, and for less anticipated lawsuits. We also document a stronger same-country spillover for a recent wave of U.S. lawsuits targeting Chinese issuers than for other standalone litigations. Finally, a non-sued firm’ litigation price reaction predicts its future litigation risk. Our findings are consistent with investors updating litigation risks of peer firms upon litigation events, and highlight the importance of U.S. shareholder lawsuits in disciplining foreign issuers.
- Published
- 2013
308. Transforming Nickel Hydroxide into 3D Prussian Blue Analogue Array to Obtain Ni2P/Fe2P for Efficient Hydrogen Evolution Reaction.
- Author
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Yuancai Ge, Pei Dong, Craig, Steven R., Ajayan, Pulickel M., Mingxin Ye, and Jianfeng Shen
- Subjects
HYDROXIDES ,PRUSSIAN blue ,HYDROGEN evolution reactions ,TITANIUM ,METAL foils - Abstract
For the first time, a 3D Prussian blue analogue (PBA) with well-defined spatial organization is fabricated by using a nickel hydroxide array as a precursor. The nickel hydroxide arrays are synthesized in titanium foil and reacted with K3[Fe(CN)6]. The plate-like morphology of the nickel hydroxide is perfectly preserved and combined with abundant PBA nanocubes. After phosphidation at 350 °C, the obtained sample demonstrated excellent hydrogen evolution reaction (HER) activity in both acid and alkaline solutions to reach a current density of 10 mA cm
-2 with an overpotential of only 70 and 121 mV, respectively. With an overpotential of 266 mV, it can reach a larger current density of 500 mA cm-2 in acid. The efficient HER activity of the obtained sample is mainly ascribed to its structural advantage with various active metal sites derived from the nickel hydroxide and PBA precursor. In addition, long-term stability measurements have verified the good performance of the obtained sample in acid and alkaline solutions. An increment of overpotential of only 8 and 9 mV is observed, in the acid and alkaline solutions respectively. Beyond these assets, it is supposed that the strategy to synthesize 3D PBA arrays from nickel hydroxide can be extended to other metal-organic frameworks arrays for more electrochemical applications. [ABSTRACT FROM AUTHOR]- Published
- 2018
- Full Text
- View/download PDF
309. mir-30d regulates multiple genes in the autophagy pathway and impairs autophagy process in human cancer cells
- Author
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Jianfeng Shen, Angela DeMichele, Xiaomin Zhong, Xiaojun Yang, Congjian Xu, Tim M. Zheng, Janos L. Tanyi, Peng Gao, and Lin Zhang
- Subjects
Programmed cell death ,ATG5 ,Biophysics ,Vesicular Transport Proteins ,Autophagy-Related Proteins ,Biology ,BAG3 ,Biochemistry ,Article ,Autophagy-Related Protein 5 ,ATG12 ,Cell Line, Tumor ,Neoplasms ,Proto-Oncogene Proteins ,Autophagy ,Humans ,Molecular Biology ,Tumor Suppressor Proteins ,Membrane Proteins ,Cell Biology ,BECN1 ,Oncomir ,Cell biology ,Gene Expression Regulation, Neoplastic ,MicroRNAs ,Cell Transformation, Neoplastic ,Cancer cell ,Small Ubiquitin-Related Modifier Proteins ,Beclin-1 ,Apoptosis Regulatory Proteins ,Carrier Proteins ,Microtubule-Associated Proteins ,Autophagy-Related Protein 12 - Abstract
In human epithelial cancers, the microRNA (miRNA) mir-30d is amplified with high frequency and serves as a critical oncomir by regulating metastasis, apoptosis, proliferation, and differentiation. Autophagy, a degradation pathway for long-lived protein and organelles, regulates the survival and death of many cell types. Increasing evidence suggests that autophagy plays an important function in epithelial tumor initiation and progression. Using a combined bioinformatics approach, gene set enrichment analysis, and miRNA target prediction, we found that mir-30d might regulate multiple genes in the autophagy pathway including BECN1, BNIP3L, ATG12, ATG5, and ATG2. Our further functional experiments demonstrated that the expression of these core proteins in the autophagy pathway was directly suppressed by mir-30d in cancer cells. Finally, we showed that mir-30d regulated the autophagy process by inhibiting autophagosome formation and LC3B-I conversion to LC3B-II. Taken together, our results provide evidence that the oncomir mir-30d impairs the autophagy process by targeting multiple genes in the autophagy pathway. This result will contribute to understanding the molecular mechanism of mir-30d in tumorigenesis and developing novel cancer therapy strategy.
- Published
- 2012
310. CoNi2S4-Graphene-2D-MoSe2as an Advanced Electrode Material for Supercapacitors
- Author
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Liyuan Pei, Xiang Zhang, Zhuqing Zhang, Marco-Tulio F. Rodrigues, Jianfeng Shen, Jingjie Wu, Mingxin Ye, Pulickel M. Ajayan, and Fangfang Zhang
- Subjects
Horizontal scan rate ,Supercapacitor ,Nanocomposite ,Materials science ,Renewable Energy, Sustainability and the Environment ,Graphene ,Nanoparticle ,Nanotechnology ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Capacitance ,0104 chemical sciences ,law.invention ,law ,Electrode ,General Materials Science ,0210 nano-technology ,Current density - Abstract
3D CoNi2S4-graphene-2D-MoSe2 (CoNi2S4-G-MoSe2) nanocomposite is designed and prepared using a facile ultrasonication and hydrothermal method for supercapacitor (SC) applications. Because of the novel nanocomposite structures and resultant maximized synergistic effect among ultrathin MoSe2 nanosheets, highly conductive graphene and CoNi2S4 nanoparticles, the electrode exhibits rapid electron and ion transport rate and large electroactive surface area, resulting in its amazing electrochemical properties. The CoNi2S4-G-MoSe2 electrode demonstrates a maximum specific capacitance of 1141 F g−1, with capacitance retention of ≈108% after 2000 cycles at a high charge–discharge current density of 20 A g−1. As to its symmetric device, 109 F g−1 at a scan rate of 5 mV s−1 is exhibited. This pioneering work should be helpful in enhancing the capacitive performance of SC materials by designing nanostructures with efficient synergetic effects.
- Published
- 2016
311. One-pot synthesis of single-crystal Pt nanoplates uniformly deposited on reduced graphene oxide, and their high activity and stability on the electrocalalytic oxidation of methanol
- Author
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Jianfeng Shen, Li Niu, Xudan Wang, Ai-Jun Wang, Shengtang Huang, Yanfei Hao, and Junhua Yuan
- Subjects
Materials science ,Inorganic chemistry ,Oxide ,chemistry.chemical_element ,Bioengineering ,02 engineering and technology ,010402 general chemistry ,01 natural sciences ,Catalysis ,law.invention ,chemistry.chemical_compound ,Transition metal ,law ,medicine ,General Materials Science ,Electrical and Electronic Engineering ,Graphene oxide paper ,Polyvinylpyrrolidone ,Graphene ,Mechanical Engineering ,General Chemistry ,021001 nanoscience & nanotechnology ,0104 chemical sciences ,chemistry ,Chemical engineering ,Mechanics of Materials ,Methanol ,0210 nano-technology ,Platinum ,medicine.drug - Abstract
We demonstrate a one-pot thermoreduction approach towards the preparation of single-crystal Pt nanoplates, which were uniformly deposited on the reduced graphene oxide (RGO) using polyvinylpyrrolidone (PVP) as a stabilizer. The size of Pt nanoplates can be tuned from 6.8 to 10.1 nm by controlling Pt loading. The as-prepared Pt/PVP/RGO catalysts show high stability and activity towards the methanol oxidation reaction (MOR). Their MOR current can reach up to 401 mA mg(-1) Pt and MOR current can maintain 89.4% of its initial value after 10 000 potential cycles.
- Published
- 2016
312. Exfoliated 2D Transition Metal Disulfides for Enhanced Electrocatalysis of Oxygen Evolution Reaction in Acidic Medium
- Author
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Xiaolong Zou, Ken Hackenberg, Yingchao Yang, Jingjie Wu, Yong Yan, Jing Gu, Jianfeng Shen, Jun Lou, Kuntal Chatterjee, Mingjie Liu, and Pulickel M. Ajayan
- Subjects
Chemistry ,Mechanical Engineering ,Inorganic chemistry ,Oxygen evolution ,Acid water ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Electrocatalyst ,01 natural sciences ,Exfoliation joint ,0104 chemical sciences ,Anode ,Catalysis ,Chemical engineering ,Transition metal ,Mechanics of Materials ,Water splitting ,0210 nano-technology - Abstract
The scarcity of inexpensive and efficient electrocatalyst for acid water oxidation to molecular oxygen presents the development of nonprecious catalysts for water oxidation a scientific priority. For water splitting, transition-metal dichalcogenides have attracted great interest as advanced catalysts for hydrogen evolution reaction, but there has been no sincere attention to generate significant anodic current density of oxygen evolution reaction (OER) with these materials. Addressing this unmet need, here, the outstanding catalytic performance of MoS2 and TaS2 in OER is demonstrated. Chemically exfoliated 2D thin sheets of MoS2 and TaS2, in both of their 1T and 2H polymorph, have been employed for OER catalysis in acid medium. The best performance for oxygen evolution, which is also comparable to benchmark IrO2, comes out from 1T-MoS2 followed by 1T-TaS2, 2H-MoS2, and 2H-TaS2. Theoretical study reveals that the dominant catalytic activity is on edge sites instead of surface and corroborates the experimental results of polymorphic dependence of electrocatalytic activity. The materials have also shown moderate durability in the harsh acidic medium. The study brings up new set of electrocatalyst for oxygen evolution in acid regime that hitherto has remained largely unrevealed.
- Published
- 2016
313. Building Castles in the Air: Evidence from Industry IPO Waves
- Author
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Zhi Da, Ravi Jagannathan, and Jianfeng Shen
- Subjects
jel:G17 ,jel:G14 ,jel:G12 ,jel:G02 ,jel:G10 - Abstract
We provide empirical support for the conventional wisdom that there are times when optimistic investors tend to build their hopes into castles in the air, and pay a large premium over intrinsic value for stocks of firms in the early stages of their life cycles with perceived growth opportunities. We use industry IPO waves containing a set of firms in the same industry that went public at about the same time in a cluster to identify those time periods and firms that are relatively homogenous and in the same early growth stages of their life cycles. We find that three years after an industry IPO wave ends, among the firms in the wave with relatively high historical sales growth rates, those with low gross margins are over-valued relative to firms with high gross margins. They under-perform their industry IPO wave peers by 0.92% per month, or about 12% per year, during the subsequent four-year period after adjusting for risk and firm characteristics differentials. Further, the average future returns on these firms are even below the corresponding risk-free returns. Our findings contribute to the literature on inefficient capital markets by identifying situations when prices of some stocks are likely to be affected by bounded rationality or biases in the way investors make decisions, and agency issues limit the ability of more sophisticated arbitrageurs who have to rely on other people's money from exploiting any resultant profit opportunities.
- Published
- 2012
314. Preparation and characterization of pH- and temperature-responsive nanocomposite double network hydrogels
- Author
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Xin Lu, Na Li, Zhiqiang Li, Hongwei Ma, Mingxin Ye, Min Shi, and Jianfeng Shen
- Subjects
Materials science ,Compressive Strength ,Oxide ,Acrylic Resins ,Bioengineering ,Nanocomposites ,Biomaterials ,chemistry.chemical_compound ,X-Ray Diffraction ,Polymer chemistry ,Materials Testing ,Spectroscopy, Fourier Transform Infrared ,medicine ,Nanocomposite ,Aqueous solution ,Calorimetry, Differential Scanning ,Polyacrylic acid ,Temperature ,Hydrogels ,Hydrogen-Ion Concentration ,Freeze Drying ,chemistry ,Polymerization ,Acrylates ,Mechanics of Materials ,Silanization ,Self-healing hydrogels ,Graphite ,Stress, Mechanical ,Swelling ,medicine.symptom - Abstract
A methodology is described for the preparation of pH- and temperature-responsive double network (DN) hydrogels with poly(N-isopropylacrylamide) (PNIPAM) as a tightly crosslinked 1st network, polyacrylic acid (PAA) as a loosely crosslinked 2nd network and graphene oxide (GO) as an additive. GO sheets were first prepared via an oxidation reaction and then dispersed in NIPAM aqueous solution via silanization. Free-radical polymerization of NIPAM was carried out at 20 °C in a water bath, and then subjected to UV light, leading to the formation of pH- and temperature-responsive PNIPAM/AA/GO DN hydrogels. The effects of GO sheets and AA contents on various physical properties were investigated. Results show that PNIPAM/AA/GO hydrogels undergo a large volumetric change in response to temperature. It also exhibits significantly fast swelling/deswelling compared with conventional PNIPAM hydrogel. Moreover, the PNIPAM/AA/GO hydrogels have a much better mechanical property than the conventional PNIPAM hydrogels.
- Published
- 2012
315. Gross Margin: A Leading Indicator of Losers in Industry IPO Waves
- Author
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Zhi Da, Ravi Jagannathan, and Jianfeng Shen
- Published
- 2012
316. The Global Relation between Financial Distress and Equity Returns
- Author
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Pengjie Gao, Jianfeng Shen, and Christopher A. Parsons
- Subjects
Individualism ,Shareholder ,Creditor ,Financial economics ,Expropriation ,Equity (finance) ,Economics ,Stock (geology) ,Credit risk ,Overconfidence effect - Abstract
Recent studies conflict sharply about the stock returns of financially distressed firms. Both the basic empirical pattern and interpretation have been challenged. This study addresses both critiques. Analyzing about 4.3 million firm-months observations in 38 countries from January 1992 to June 2013, we find a strong, negative link between credit risk and subsequent equity returns, concentrated among low-capitalization stocks in developed countries in North America and Europe. Comparisons between countries reveal: 1) no relation to creditor rights, inconsistent with theories based on shareholders expropriation, but 2) a strong, positive relation to individualism, a proxy for investor overconfidence. Additional analysis using within-country proxies for investor overconfidence further supports an overconfidence-based explanation.
- Published
- 2012
317. Effectiveness of HBV vaccination in infants and prediction of HBV prevalence trend under new vaccination plan: findings of a large-scale investigation
- Author
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Jun Yao, Bin Ju, Shigui Yang, Chunxia Zhu, Bing Ruan, Min Deng, Yu Chen, Lanjuan Li, Wei Wu, Chengbo Yu, Jingjing Ren, Ming D. Li, Ping Chen, Bing Wang, and Jianfeng Shen
- Subjects
Male ,lcsh:Medicine ,Hbv vaccination ,medicine.disease_cause ,Hepatitis ,Sex factors ,Prevalence ,Medicine ,Child ,lcsh:Science ,Aged, 80 and over ,Vaccines ,Multidisciplinary ,Vaccination ,Age Factors ,virus diseases ,Alanine Transaminase ,Middle Aged ,Hepatitis B ,Immunizations ,Child, Preschool ,Hepatocellular carcinoma ,Scale (social sciences) ,Carrier State ,Infectious diseases ,Female ,Public Health ,Research Article ,Adult ,China ,Hepatitis B virus ,medicine.medical_specialty ,Infectious Disease Control ,Adolescent ,Viral diseases ,macromolecular substances ,Microbiology ,Hepatitis B, Chronic ,Sex Factors ,Virology ,Environmental health ,Humans ,Hepatitis B Vaccines ,Biology ,Aged ,Hepatitis B Surface Antigens ,business.industry ,Public health ,lcsh:R ,Immunity ,Infant ,Viral Vaccines ,medicine.disease ,digestive system diseases ,Immunology ,Clinical Immunology ,lcsh:Q ,business ,Biomarkers ,Forecasting - Abstract
BACKGROUND: Hepatitis B virus (HBV) infection remains a severe public health problem. Investigating its prevalence and trends is essential to prevention. METHODS: To evaluate the effectiveness of HBV vaccination under the 1992 Intervention Program for infants and predicted HBV prevalence trends under the 2011 Program for all ages. We conducted a community-based investigation of 761,544 residents of 12 counties in Zhejiang Province selected according to their location, population density, and economic development. The HBV prevalence trends were predicted by a time-shifting approach. HBV surface antigen (HBsAg) and alanine amino transferase (ALT) were determined. RESULTS: Of the 761,544 persons screened for HBsAg, 54,132 were positive (adjusted carrier rate 6.13%); 9,455 had both elevated ALT and a positive HBsAg test (standardized rate 1.18%). The standardized HBsAg carrier rate for persons aged ≤20 years was 1.51%. Key factors influencing HBV infection were sex, age, family history, drinking, smoking, employment as a migrant worker, and occupation. With the vaccination program implemented in 2011, we predict that by 2020, the HBsAg carrier rate will be 5.27% and that for individuals aged ≤34 years will reach the 2% upper limit of low prevalence according to the WHO criteria, with a standardized rate of 1.86%. CONCLUSIONS: The national HBV vaccination program for infants implemented in 1992 has greatly reduced the prevalence of HBV infection. The 2011 program is likely to reduce HBV infection in Zhejiang Province to a low moderate prevalence, and perinatal transmission is expected to be controlled by 2020.
- Published
- 2012
318. Growth versus Margin and Castles in the Air: Evidence from Industry IPO Waves
- Author
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Jianfeng Shen, Zhi Da, and Ravi Jagannathan
- Subjects
Sales growth ,Actuarial science ,Optimism ,media_common.quotation_subject ,Business ,Monetary economics ,Initial public offering ,Limits to arbitrage ,Stock (geology) ,Gross margin ,media_common - Abstract
We provide novel evidence supporting the view that stock prices of some firms in the early growth stage of their life cycle are set by optimistic investors fixated on sales growth. We identify these firms as those that went public during an industry IPO waves, had high sales growths but low gross margins in the first three years following the IPO. Consistent with overpricing, their stocks under-perform their peers by 0.92% per month during the subsequent four year period on a risk-adjusted basis, suggesting limits to arbitrage. This pattern is unrelated to the well documented long-run under-performance of IPOs.
- Published
- 2012
319. Information, Analysts, and Stock Return Co-movement
- Author
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Jianfeng Shen, Randall Morck, Bernard Yeung, and Allaudeen Hameed
- Subjects
Growth stock ,Intermediary ,Financial economics ,Information spillover ,Business ,Stock return - Abstract
Analysts follow disproportionally firms whose fundamentals correlate more with those of their industry peers. This coverage pattern supports models of profit-maximizing information intermediaries producing preferentially information valuable in pricing more stocks. We designate highly followed firms whose fundamentals best predict those of peer firms as bellwether firms. When analysts revise a bellwether firm’s earning forecast, it changes the prices of other firms significantly; however, revisions for firms that are less intensely followed do not change the prices of heavily followed firms. Unidirectional information spillovers explain how the more accurately priced stocks might exhibit more comovement.
- Published
- 2012
320. ChemInform Abstract: Synthesis of Heterocyclic Substituted Norcantharidin Derivatives
- Author
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Liping Deng, Weifeng Tao, Wei Wang, Jianfeng Shen, and Zhang Yong
- Subjects
chemistry.chemical_compound ,Norcantharidin ,chemistry ,hemic and lymphatic diseases ,Moiety ,Biological activity ,General Medicine ,Thiazole ,Combinatorial chemistry - Abstract
The synthesis of the novel title compounds (VI) and (VIII) with a biologically active thiazole moiety is presented.
- Published
- 2011
321. ChemInform Abstract: Synthesis of Norcantharidin-Dimer Derivatives
- Author
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Wei Wang, Zhang Yong, Liping Deng, Weifeng Tao, and Jianfeng Shen
- Subjects
chemistry.chemical_compound ,Norcantharidin ,chemistry ,Dimer ,Chloroamine ,Organic chemistry ,General Medicine ,Combinatorial chemistry ,Cycloaddition - Abstract
The title compounds (VI) and (VIII) are prepared via [3 + 2] 1,3-dipolar cycloaddition in the presence of chloroamine T, a method that is simpler than the conventional procedure.
- Published
- 2011
322. Synthesis of graphene oxide-based biocomposites through diimide-activated amidation
- Author
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Bo Yan, Jianfeng Shen, Hongwei Ma, Na Li, Mingxin Ye, and Min Shi
- Subjects
Materials science ,Composite number ,Oxide ,Infrared spectroscopy ,Nanotechnology ,Biocompatible Materials ,Microscopy, Atomic Force ,law.invention ,Biomaterials ,chemistry.chemical_compound ,Colloid and Surface Chemistry ,law ,Diimide ,Spectroscopy, Fourier Transform Infrared ,Graphene ,Biomaterial ,Oxides ,Electrochemical Techniques ,Amides ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,chemistry ,Chemical engineering ,Transmission electron microscopy ,Covalent bond ,Graphite - Abstract
In this work, a novel and facile method for covalent attachment of biomaterials to graphene oxide sheets (GOS) was developed. Four conjugates were obtained via the diimide-activated amidation reaction under ambient conditions. Final products were characterized by FT-IR spectroscopy, atomic force microscopy and transmission electron microscopy. Electrochemical characterization of the composite showed that the covalently bonded biomaterial retained its bioactivity. This method may provide a way for further preparation of graphene-based biodevices.
- Published
- 2010
323. Anti-VEGF effects of intravitreal erythropoietin in early diabetic retinopathy
- Author
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Yong Zhong, Weiye Li, Jingfa Zhang, Jianfeng Shen, Liumei Hu, Stephen H. Sinclair, Guo-Tong Xu, Y. Luo, Myron Yanoff, Yalan Wu, and Guoxu Xu
- Subjects
Male ,Vascular Endothelial Growth Factor A ,medicine.medical_specialty ,Alpha (ethology) ,Endogeny ,Polymerase Chain Reaction ,General Biochemistry, Genetics and Molecular Biology ,Rats, Sprague-Dawley ,hemic and lymphatic diseases ,Internal medicine ,Diabetes mellitus ,Blood-Retinal Barrier ,medicine ,In Situ Nick-End Labeling ,Animals ,Receptor ,Erythropoietin ,DNA Primers ,Diabetic Retinopathy ,General Immunology and Microbiology ,Base Sequence ,business.industry ,Diabetic retinopathy ,medicine.disease ,Erythropoietin receptor ,Rats ,Vitreous Body ,Microscopy, Electron ,Endocrinology ,business ,Retinopathy ,medicine.drug - Abstract
In the present study, a single intravitreal erythropoietin (EPO) to diabetic rats produced therapeutic effects on blood-retinal barrier (BRB) function and neuronal survival at different time courses of retinopathy. In parallel, the hypoxia-inducible factor 1 alpha (HIF-1 alpha) pathway has been quantitatively studied, including VEGF-A, endogenous EPO, EPO receptor (EpoR), prolyl hydroxylases (PHD1-3) and von Hippel-Lindau tumor suppressor (VHL). The mRNA levels of HIF-1 alpha, VEGF-A, endogenous EPO, PHD1-3 and VHL are all up-regulated in the diabetic retina, and suppressed by exogenous EPO. The increased protein levels of HIF-1 alpha, VEGF-A, and endogenous EPO found in diabetic retinas also have been down-regulated by exogenous EPO. The results demonstrate that the HIF-1 pathway is activated in the retina in early diabetes, but is negatively regulated by a feedback loop following the administration of exogenous EPO. Exogenous EPO at pharmacologic levels leads to suppression of VEGF and in turn, restoration of the normal functions of BRB in a time-dependent manner. In the diabetic retina, the same level of exogenous EPO that inhibits VEGF also exerted neuronal protection.
- Published
- 2010
324. Information, analysts, and stock return comovement
- Author
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Allaudeen Hameed, Randall Morck, Jianfeng Shen, and Bernard Yeung
- Published
- 2010
325. An Effective Method for Foreground Segmentation of Video
- Author
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Jianfeng Shen, Zongqing Lu, and Qingmin Liao
- Subjects
Markov random field ,Pixel ,Computer science ,business.industry ,ComputingMethodologies_IMAGEPROCESSINGANDCOMPUTERVISION ,Scale-space segmentation ,Markov process ,Image segmentation ,symbols.namesake ,Robustness (computer science) ,Computer Science::Computer Vision and Pattern Recognition ,symbols ,Computer vision ,Segmentation ,Artificial intelligence ,business ,Gibbs sampling - Abstract
In this paper, we propose a novel foreground segmentation approach for applications using static cameras. The foreground segmentation is modeled as an energy function optimum process, where energy function is based on Markov Random Field (MRF) and efficiently optimized by Gibbs sampling. The essence of our method is that we fuse four foreground/background models based on color and texture. This allows composing a robust likelihood term that not only reflects the appearance of foreground/background, but also models the shadow removal process, together with a spatial contrast term and a better temporal persistence term, which achieves a more accurate segmentation. This method has been run on both indoor and outdoor sequences, and the results have proved its effectiveness.
- Published
- 2009
326. ERK- and Akt-dependent neuroprotection by erythropoietin (EPO) against glyoxal-AGEs via modulation of Bcl-xL, Bax, and BAD
- Author
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Weiye Li, Guoxu Xu, Myron Yanoff, Yalan Wu, Jingfa Zhang, Guo-Tong Xu, Jianfeng Shen, Jing-Ying Xu, and Stephen H. Sinclair
- Subjects
MAPK/ERK pathway ,Glycation End Products, Advanced ,Male ,Time Factors ,Cell Survival ,Blotting, Western ,bcl-X Protein ,Bcl-xL ,Neuroprotection ,Cell Line ,Rats, Sprague-Dawley ,chemistry.chemical_compound ,Organ Culture Techniques ,medicine ,In Situ Nick-End Labeling ,Animals ,Propidium iodide ,RNA, Messenger ,Phosphorylation ,Extracellular Signal-Regulated MAP Kinases ,Protein kinase B ,Erythropoietin ,Cell Proliferation ,bcl-2-Associated X Protein ,biology ,Dose-Response Relationship, Drug ,Cell growth ,Reverse Transcriptase Polymerase Chain Reaction ,Glyoxal ,Flow Cytometry ,Cell biology ,Rats ,Up-Regulation ,Oxidative Stress ,Neuroprotective Agents ,chemistry ,Cell culture ,biology.protein ,bcl-Associated Death Protein ,Apoptosis Regulatory Proteins ,Proto-Oncogene Proteins c-akt ,medicine.drug ,Retinal Neurons - Abstract
Purpose To characterize the neuroprotective mechanisms of erythropoietin (EPO) against the stress of glyoxal-advanced glycation end products (AGEs) in retinal neuronal cells. Methods Rat retinal organ culture, primary retinal neuron culture, and retinal cell line (R28 cell) culture under glyoxal-AGEs insult were used as in vitro models. Exogenous EPO was applied to these models. Retinal neuronal cell death was assessed by TUNEL, ethidium bromide/acridine orange staining, and cell viability assay. R28 cell proliferation was evaluated by BrdU incorporation and propidium iodide staining. Real-time RT-PCR and Western blot analysis were used to detect Bcl-xL, Bcl-2, Bax, BAD, and products of extracellular signal regulated kinase (ERK) and Akt pathways. Specific inhibitors and plasmids were used to pinpoint the roles of ERK and Akt pathways. Results. EPO protected the retinal cells from glyoxal-AGE-induced injury in a time- and dose-dependent fashion. The protective function of EPO was proved to be antiapoptotic, not pro-cell proliferative. Glyoxal upregulated Bax expression but suppressed Bcl-xL expression and BAD phosphorylation. In contrast, EPO enhanced BAD phosphorylation and Bcl-xL expression but downregulated Bax. The regulation of these apoptosis-related proteins by EPO was through ERK and Akt pathways. Conclusions These data demonstrate that exogenous EPO significantly attenuates the retinal neuronal cell death induced by glyoxal-AGEs by promoting antiapoptotic and suppressing apoptotic proteins. EPO/EPO receptor signaling through ERK and Akt pathways is pivotal in EPO neuroprotective mechanisms.
- Published
- 2009
327. ChemInform Abstract: Copper(I) Bromide Promoted Selective Reduction of N-Substituted Phthalimides with Zinc
- Author
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Li-Xin Wang, Wen Wang, Jianfeng Shen, Fan Yang, and Ji-Yu Wang
- Subjects
Phthalimides ,chemistry.chemical_compound ,Chemistry ,Organic chemistry ,chemistry.chemical_element ,Copper(I) bromide ,Selective reduction ,General Medicine ,Zinc - Published
- 2008
328. Layer-by-layer self-assembly of multiwalled carbon nanotube polyelectrolytes prepared by in situ radical polymerization
- Author
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Mingxin Ye, Yizhe Hu, Chen Qin, and Jianfeng Shen
- Subjects
Thermogravimetric analysis ,Nanotube ,Materials science ,Radical polymerization ,Infrared spectroscopy ,Surfaces and Interfaces ,Carbon nanotube ,Condensed Matter Physics ,Polyelectrolyte ,law.invention ,Chemical engineering ,Polymerization ,law ,Polymer chemistry ,Electrochemistry ,General Materials Science ,Fourier transform infrared spectroscopy ,Spectroscopy - Abstract
Anionic and cationic multiwalled carbon nanotube polyelectrolytes, prepared by covalent modification of multiwalled carbon nanotubes (MWCNTs) with poly(acrylic acid) and poly(acrylamide), were used for the layer-by-layer (LBL) self-assembly of MWCNTs on different substrates with polyelectrolytes, such as poly(diallyldimethylammonium chloride) and sodium poly(styrenesulfonate). Thermogravimetric analysis, Raman spectroscopy, and scanning electron microscopy (SEM) were used to demonstrate the modification of MWCNTs. Investigations using Fourier transform infrared spectroscopy, atomic force microscopy, SEM, and ultraviolet−visible spectroscopy proved this method to be practicable for preparing LBL films.
- Published
- 2008
329. The Relationship between the Frequency of News Release and the Information Asymmetry: The Role of Informed Trading and Uninformed Trading
- Author
-
Srinivasan Sankaraguruswamy, Takeshi Yamada, and Jianfeng Shen
- Subjects
Actuarial science ,Information asymmetry ,Economics ,Adverse selection ,Monetary economics ,Endogeneity - Abstract
This paper shows that the degree of information asymmetry is lower for firms with more frequent news releases. The relation holds for various measures of information asymmetry such as the probability of information-based trading (PIN), permanent price impact, and adverse selection component of bid-ask spread, even after adjusting for endogeneity between news release and information asymmetry. By decomposing the PIN into intensities of uninformed and informed trades, similarly to Brown and Hillegeist [2007, Review of Accounting Studies 12, 443-477], we find that intensity of uninformed trading increases much more than that of informed trading for firms with more frequent news releases. As a result, information asymmetry, as is measured by PIN, decreases for such firms due to the large increase in the intensity of uninformed trading. Our findings highlight not only the importance of news releases in leveling the playing field of investors but also the role of uninformed investors in reducing trading cost due to information asymmetry.
- Published
- 2008
330. Idiosyncratic Volatility: Information or Noise?
- Author
-
Jianfeng Shen
- Subjects
Public information ,Econometrics ,Economics ,Volatility (finance) ,Explanatory power ,Private information retrieval ,Stock (geology) - Abstract
Roll (1988) finds that idiosyncratic influences strongly dominate systematic influences in stock returns. However, it is extensively debated that whether the prevailing idiosyncratic influences are due to firm-specific information or noise. In this paper, I empirically address this question by examining the contribution of the proxies of private information, public information and noise to the variation of idiosyncratic volatility. My empirical findings suggest that the amount of private information incorporated in the prices strongly dominates public information and noise in driving variation of idiosyncratic volatility. Furthermore, the explanatory power of noise for idiosyncratic volatility decreases with the horizon over which returns are measured. The findings in this paper support the information-based interpretation of idiosyncratic volatility that prices of stocks with greater idiosyncratic volatility are more informative.
- Published
- 2008
331. Novel Electrocatalysts for Generating Oxygen from Acid Water Electrolysis
- Author
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Kuntal Chatterjee, Jingjie Wu, Jianfeng Shen, Ken Hackenberg, Robert Vajtai, Jun Lou, and Pulickel M Ajayan
- Abstract
Rapidly increasing global energy demand and developing carbon-neutral economy impose great challenge to the scientific community and it requires untiring efforts to exploit and store abundant but diffuse renewable energy sources. One innovative and promising approach for that is the efficient production of hydrogen serving as fuel, through electricity-driven water splitting. However, the overall efficiency of the reaction is largely impeded by the kinetically sluggish oxygen evolution reaction (OER), imposing serious overpotential requirement. Therefore, an efficient oxygen evolution catalyst is essential to enhance the reaction rate and/ or lower the overpotential. Although precious metal oxides, such as RuO2 and IrO2, are considered to be the most active OER electrocatalysts, they are not suitable for large-scale applications because of their scarcity and high costs. So There is an ongoing interest to find earth-abundant and inexpensive electrocatalysts for OER. In response, non-noble transition-metal-based oxides, layered double hydroxides (LDH), perovskite-type metal oxides are some of the advance electrocatalyst candidates with their own limitations. Here, for the first time, we focus on layered transition metal dicalchogenides (TMDs) like MoS2 and TaS2 in this search due to their natural abundance and high activity towards hydrogen evolution. We report MoS2 and TaS2, in both their 2H and 1T polymorphs that display excellent catalytic activity for OER in much required acid medium. They are chemically exfoliated to thinner nanosheets from MoS2 precursor and TaS2 nanostructures synthesized by chemical vapour deposition. Structural and electrochemical studies reveal their corresponding semiconducting 2H and metallic 1T polymorph and the impressive electrocatalytic performance respectively. The proliferation of active sites is such a high for those materials that an electrocatalytic current density of 10 mA cm− 2 is achievable with overpotential much lower than that of the benchmark IrO2 or RuO2OER catalyst. The Tafel slopes found for the different samples are also in good rivalry of the benchmark catalyst. The performances are also analyzed on the basis of their probable structure relation. This work presents general strategies to grow nanostructures of layered TMD materials for the enhanced catalytic performance in OER and open up a new avenue in the pursuance of water splitting research towards the growth of hydrogen economy.
- Published
- 2015
332. Impact of Firm-Specific Public Information on the Relation between Prices and Trading
- Author
-
Takeshi Yamada, Jianfeng Shen, and Srinivasan Sankaraguruswamy
- Subjects
Public information ,Information asymmetry ,Signal extraction ,Price pressure ,Business ,Monetary economics ,Volatility (finance) ,Price discovery ,Private information retrieval - Abstract
Investors can interpret public information homogenously, which has the effect of reducing information asymmetry. Prices would react to the release of public information and trading plays a secondary role in price discovery. However, investors can interpret public information heterogeneously and this triggers private information acquisition by sophisticated investors. In such a scenario, trading plays a central role in price discovery. We empirically investigate the role of public information on the order flow return relation as well as the volume volatility relation, using www.marketwatch.com as a proxy for firm-specific public information flow, for 1099 NYSE firms during calendar year 2002. We find that the relation between order flow and returns is significantly higher on the days with public information release. This suggests that the releases of firm-specific public information triggers private information collection and superior signal extraction by sophisticated investors. We also find that the same is true for the relation between volume and volatility. Public information release results in increased divergence of beliefs, and hence a higher volume volatility relation on days with public information release. Thus trading plays a central role in price discovery around public information release. In sensitivity tests we find that price pressure is not an explanation for the higher order flow return relation and volume volatility relation on days with public information release.
- Published
- 2006
333. Optimization Algorithm for Pick-up Operation Scheduling of Container Yard
- Author
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Jianfeng Shen, Chun Jin, and Peng Gao
- Subjects
Yard ,Mathematical optimization ,Basis (linear algebra) ,Computer science ,Heuristic (computer science) ,Container (abstract data type) ,Path (graph theory) ,Shortest path problem ,Genetic algorithm ,Process (computing) - Abstract
On the basis of analyzing the pick-up operation process for import containers on the gate side of container yard, a multi-phase optimization mathematical model was established, which aimed to minimize the total cost of pick-up operation process. This model was comprised of two sub-models: rehandling operation scheduling and the shortest path searching. A two-layer A* heuristic algorithm was put forward and realized, where the inner A* algorithm structure was embedded into the outer one; the inner A* algorithm was responsible for searching the shortest rehandling operation path, and the outer A* algorithm for optimizing rehandling strategy. By comparing this A* algorithm with genetic algorithm using the same actual case, the conclusion is that A* algorithm presents better performance both in optimization result and execution efficiency
- Published
- 2006
334. A Nested Genetic Algorithm for Optimal Container Pick-Up Operation Scheduling on Container Yards
- Author
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Jianfeng Shen, Chun Jin, and Peng Gao
- Subjects
Mathematical optimization ,education.field_of_study ,Optimization problem ,Computer science ,Shortest path problem ,Population ,Genetic algorithm ,Operation scheduling ,education ,Algorithm - Abstract
For the optimization problem on container pick-up operation scheduling, a multi-stage mathematical programming model is established to minimize the total operation cost. This model is comprised of two parts: rehandling operation scheduling and the shortest path search. A nested genetic algorithm with two layers is proposed, where the inner layer algorithm is embedded in the outer one. The outer algorithm is responsible for optimizing rehandling operation scheduling, and the inner is for searching the shortest path of rehandling operation. Two reformative operations are introduced, including the parent population involving selection and optimal individual maintaining. With an actual example, the algorithm is testified, the result shows that the algorithm is effective to solve this problem and has a high efficiency and speed of convergence.
- Published
- 2006
335. Accelerated Lane-Changing Trajectory Planning of Automated Vehicles with Vehicle-to-Vehicle Collaboration.
- Author
-
Haijian Bai, Jianfeng Shen, Liyang Wei, and Zhongxiang Feng
- Subjects
- *
AUTONOMOUS underwater vehicles , *ROBOTIC trajectory control , *CITY traffic , *AUTOMATION ,TRAFFIC flow measurement - Abstract
Considering the complexity of lane changing using automated vehicles and the frequency of turning lanes in city settings, this paper aims to generate an accelerated lane-changing trajectory using vehicle-to-vehicle collaboration (V2VC). Based on the characteristics of accelerated lane changing, we used a polynomial method and cooperative strategies for trajectory planning to establish a lane-changing model under different degrees of collaboration with the following vehicle in the target lane by considering vehicle kinematics and comfort requirements. Furthermore, considering the shortcomings of the traditional elliptical vehicle and round vehicle models, we established a rectangular vehicle model with collision boundary conditions by analysing the relationships between the possible collision points and the outline of the vehicle. Then, we established a simulation model for the accelerated lane-changing process in different environments under different degrees of collaboration. The results show that, by using V2VC, we can achieve safe accelerated lane-changing trajectories and simultaneously satisfy the requirements of vehicle kinematics and comfort control. [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
- View/download PDF
336. Preparation of Long Persistent SrO×2Al2O3 Ceramics and Their Luminescent Properties
- Author
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Chengkang Chang, Jianfeng Shen, Dali Mao, and Chuanli Feng
- Subjects
Lanthanide ,Photoluminescence ,Materials science ,Chemistry ,Mechanical Engineering ,Metals and Alloys ,Analytical chemistry ,Strontium aluminate ,Mineralogy ,Phosphor ,General Medicine ,Microstructure ,Afterglow ,chemistry.chemical_compound ,Mechanics of Materials ,visual_art ,Materials Chemistry ,visual_art.visual_art_medium ,Ceramic ,Porosity ,Luminescence - Abstract
Long lasting strontium aluminate phosphors were synthesized by solid state reaction in the experiment. SrO·2Al2O3 ceramics with long afterglow was firstly fabricated at 1400 °C with the aid of B2O3. The effects of B2O3 on the phase composition, porosity, density and microstructure of the sintered ceramics were investigated, as well as the effects on luminescent properties. The results indicated that B2O3 stimulated the formation of SrO·2Al2O3 by consuming the intermediate phases and helped to produce dense ceramics at 1400 °C. The ceramics hold two emission peaks at 390 and 475 nm, due to the luminescent behavior of Eu2+ in 5SrO·4Al2O3 and SrO·2Al2O3, respectively. Emission at 390 nm showed slight afterglow characteristics while emission at 475 nm illustrated good long persistence. The afterglow property was enhanced by the addition of B2O3, due to the increase in the depth of the trap center in the ceramics.
- Published
- 2003
337. Suppression of MicroRNA 200 Family Expression by Oncogenic KRAS Activation Promotes Cell Survival and Epithelial-Mesenchymal Transition in KRAS-Driven Cancer.
- Author
-
Xiaomin Zhong, Lan Zheng, Jianfeng Shen, Dongmei Zhang, Minmin Xiong, Youyou Zhang, Xinhong He, Tanyi, Janos L., Feng Yang, Montone, Kathleen T., Xiaojun Chen, Congjian Xu, Xiang, Andy P., Qihong Huang, Xiaowei Xu, and Lin Zhang
- Subjects
MICRORNA ,MESENCHYMAL stem cells ,APOPTOSIS ,TRANSCRIPTION factors ,GENE expression - Abstract
Oncogenic KRAS contributes to malignant transformation, antiapoptosis, and metastasis in multiple human cancers, such as lung, colon, and pancreatic cancers and melanoma. MicroRNAs (miRNAs) are endogenous 18- to 25-nucleotide noncoding small RNAs that regulate gene expression in a sequence-specific manner via the degradation of target mRNAs or inhibition of protein translation. In the present study, using array-based miRNA profiling in IMR90 and MCF10A cells expressing oncogenic KRAS, we identified that the expression of the microRNA 200 (mir-200) family was suppressed by KRAS activation and that this suppression was mediated by the transcription factors JUN and SP1 in addition to ZEB1. Restoration of mir-200 expression compromised KRAS-induced cellular transformation in vitro and tumor formation in vivo. In addition, we found that enforced expression of mir-200 abrogated KRAS-induced resistance to apoptosis by directly targeting the antiapoptotic gene BCL2. Finally, mir-200 was able to antagonize the epithelial-mesenchymal transition (EMT) driven by mutant KRAS. Collectively, our results suggest that repression of endogenous mir-200 expression is one of the important cellular responses to KRAS activation during tumor initiation and progression. [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
338. Preparation and characterization of pH- and temperature-responsive hydrogels with surface-functionalized graphene oxide as the crosslinker
- Author
-
Zhiqiang Li, Na Li, Hongwei Ma, Jianfeng Shen, Xin Lu, Mingxin Ye, and Min Shi
- Subjects
Aqueous solution ,Materials science ,Graphene ,Oxide ,General Chemistry ,Condensed Matter Physics ,Redox ,law.invention ,chemistry.chemical_compound ,Monomer ,chemistry ,Chemical engineering ,Polymerization ,law ,Silanization ,Polymer chemistry ,Self-healing hydrogels - Abstract
A methodology is described for the preparation of pH- and temperature-responsive semi-interpenetrating hydrogels with surface-functionalized graphene oxide (GO) as the crosslinker, N-isopropylacrylamide (NIPAM) as the monomer and sodium alginate (SA) as an additive. GO sheets were first prepared via an oxidation reaction in aqueous solution and then modified with 3-(trimethoxysilyl)propylmethacrylate (TMSPMA) via a silanization reaction. Free-radical polymerization of NIPAM and SA was then carried out with the presence of TMSPMA-modified GO sheets at 20 °C in a water bath, leading to the formation of pH- and temperature-responsive PNIPAM/SA/GO hydrogels crosslinked with TMSPMA-modified GO sheets. The effects of TMSPMA-modified GO sheets content on various physical properties were investigated. Results show that PNIPAM/SA/GO hydrogels undergo a large volumetric change in response to temperature. It also exhibits significantly larger water uptake compared to conventional PNIPAM/SA hydrogels. Moreover, the PNIPAM/SA/GO hydrogels have a much better mechanical properties than the conventional PNIPAM/SA hydrogels.
- Published
- 2012
339. Supramolecular Catenane Chemistry Based on Crown Ether Derivatives
- Author
-
Yuyuan Ye, Xuetao Yu, Huajiang Jiang, Qizhong Zhou, Rener Chen, and Jianfeng Shen
- Subjects
chemistry.chemical_classification ,chemistry ,Organic Chemistry ,Catenane ,Supramolecular chemistry ,Organic chemistry ,Crown ether - Published
- 2012
340. One-pot hydrothermal synthesis of Ag-reduced graphene oxide composite with ionic liquid
- Author
-
Hongwei Ma, Jianfeng Shen, Mingxin Ye, Na Li, Min Shi, and Bo Yan
- Subjects
Materials science ,Graphene ,Inorganic chemistry ,Oxide ,Nanoparticle ,Graphite oxide ,General Chemistry ,Ascorbic acid ,law.invention ,chemistry.chemical_compound ,symbols.namesake ,chemistry ,Chemical engineering ,law ,Materials Chemistry ,symbols ,Hydrothermal synthesis ,Raman spectroscopy ,Graphene oxide paper - Abstract
A one-pot hydrothermal reaction was used to prepare a reduced graphene oxide sheets (RGO)-silver (Ag) nanoparticles composite using graphite oxide and silver nitrate as starting materials. It was found that graphene oxide could be well reduced under the hydrothermal conditions with ascorbic acid as the reductant, while the Ag nanoparticles were grown on the RGO surface simultaneously. The reduction of graphene oxide and synthesizing of Ag-RGO were confirmed by Fourier-transform infrared spectroscopy, Raman spectroscopy, thermogravimetric analysis, X-ray diffraction and X-ray photoelectron spectroscopy. Microscopy techniques (scanning electron microscopy, atomic force microscopy and transmission electron microscopy) have been employed to probe the morphological characteristics as well as to investigate the exfoliation of RGO sheets. The intensities of the Raman signals of RGO in the composite are greatly increased by the attached Ag nanoparticles, showing surface-enhanced Raman scattering activity. Besides, it was found that the antibacterial activity of free Ag nanoparticles is retained in the composite, suggesting that it can be used as RGO-based biomaterials.
- Published
- 2011
341. One step hydrothermal synthesis of TiO2-reduced graphene oxide sheets
- Author
-
Mingxin Ye, Hongwei Ma, Na Li, Bo Yan, Min Shi, and Jianfeng Shen
- Subjects
Nanocomposite ,Materials science ,Graphene ,Oxide ,Nanotechnology ,General Chemistry ,Titanium oxide ,law.invention ,symbols.namesake ,chemistry.chemical_compound ,chemistry ,law ,Materials Chemistry ,symbols ,Hydrothermal synthesis ,Fourier transform infrared spectroscopy ,Raman spectroscopy ,Graphene oxide paper - Abstract
We demonstrated an environmentally friendly and efficient route for the preparation of titanium oxide (TiO2) nanoparticles-reduced graphene oxide composite with a one-step hydrothermal method using glucose as the reducing agent. The reducing process was accompanied by generation of TiO2 nanoparticles. The structure and composition of the nanocomposite has been characterized by Fourier transform infrared spectroscopy, Raman spectroscopy, X-ray diffraction, thermal gravimetric analysis and atomic force microscopy. The TiO2-coated RGO nanocomposite was shown to improve the photocatalytic property of TiO2, which would be promising for practical applications in future nanotechnology.
- Published
- 2011
342. Corrigendum to Facile attachment of magnetic nanoparticles to carbon nanotubes via robust linkages and its fabrication of magnetic nanocomposites [Composites Science and Technology 2009;69(3–4):s427–431]
- Author
-
Yizhe Hu, Chen Qin, Mingxin Ye, and Jianfeng Shen
- Subjects
Materials science ,Nanocomposite ,Fabrication ,law ,General Engineering ,Ceramics and Composites ,Magnetic nanoparticles ,Nanotechnology ,Carbon nanotube ,Composite material ,Science, technology and society ,law.invention - Published
- 2009
343. SB-431542 Inhibition of Scar Formation after Filtration Surgery and Its Potential Mechanism
- Author
-
Kun Liu, Guo-Tong Xu, Wen Ye, Yiqin Xiao, and Jianfeng Shen
- Subjects
MAPK/ERK pathway ,Pathology ,medicine.medical_specialty ,Cell Culture Techniques ,Receptor, Transforming Growth Factor-beta Type I ,Scars ,Dioxoles ,Smad2 Protein ,Protein Serine-Threonine Kinases ,Pharmacology ,Collagen Type I ,Conjunctival Diseases ,Injections ,Transforming Growth Factor beta1 ,Cicatrix ,Transforming Growth Factor beta2 ,chemistry.chemical_compound ,medicine ,Animals ,Humans ,RNA, Messenger ,Phosphorylation ,Fibroblast ,Protein kinase B ,Intraocular Pressure ,Connective Tissue Cells ,Wound Healing ,Reverse Transcriptase Polymerase Chain Reaction ,Cell growth ,business.industry ,Connective Tissue Growth Factor ,Cell Differentiation ,Glaucoma ,Fibroblasts ,Actins ,CTGF ,Disease Models, Animal ,medicine.anatomical_structure ,chemistry ,Benzamides ,Filtering Surgery ,Drug Therapy, Combination ,Rabbits ,SB-431542 ,medicine.symptom ,business ,Receptors, Transforming Growth Factor beta - Abstract
PURPOSE To explore the inhibitive effect of SB-431542 (an ALK5 inhibitor) on scar formation after glaucoma surgery and to identify the potential pharmacologic target(s). METHODS Twenty-four New Zealand rabbits underwent filtration surgery on the right eye and were divided into a control group and three experimental groups (n=6). Human Tenon's fibroblast monolayer was scraped to generate a single gap, and then the control medium with SB-431542 only or containing 10 microg/L TGF-beta1 and SB-431542 (1-20 microM) was added. The cells were pretreated with SB-431542 or in control medium for 30 minutes before induction with 10 microg/L TGF-beta1 or 1 microg/L TGF-beta2. The expression of alpha-SM-actin, CTGF, and Col I, as well as changes in the Smad, ERK, P38, and AKT signaling pathways were detected. RESULTS In comparison with the control rabbits, the IOPs in the experimental groups remained at lower levels until day 25 (P
- Published
- 2009
344. Liquid Phase Exfoliation of Two-Dimensional Materialsby Directly Probing and Matching Surface Tension Components.
- Author
-
Jianfeng Shen, Yongmin He, Jingjie Wu, Caitian Gao, Kunttal Keyshar, Xiang Zhang, Yingchao Yang, Mingxin Ye, Robert Vajtai, Jun Lou, and Pulickel M. Ajayan
- Subjects
- *
CONDENSED matter , *ENGINEERING design , *MACHINE design , *EXFOLIATION syndrome , *DESOLVATION , *SOLVENTS , *SURFACE tension - Abstract
Exfoliation of two-dimensional (2D)materials into mono- or few layers is of significance for both fundamentalstudies and potential applications. In this report, for the firsttime surface tension components were directly probed and matched topredict solvents with effective liquid phase exfoliation (LPE) capabilityfor 2D materials such as graphene, h-BN, WS2, MoS2, MoSe2, Bi2Se3, TaS2, and SnS2. Exfoliation efficiency is enhanced when theratios of the surface tension components of the applied solvent isclose to that of the 2D material in question. We enlarged the libraryof low-toxic and common solvents for LPE. Our study provides distinctiveinsight into LPE and has pioneered a rational strategy for LPE of2D materials with high yield. [ABSTRACT FROM AUTHOR]
- Published
- 2015
- Full Text
- View/download PDF
345. BUILDING CASTLES IN THE AIR: EVIDENCE FROM INDUSTRY IPO WAVES.
- Author
-
Da, Zhi, Jagannathan, Ravi, and Jianfeng Shen
- Published
- 2012
346. Optimization Algorithm for Pick-up Operation Scheduling of Container Yard.
- Author
-
Peng Gao, Chun Jin, and Jianfeng Shen
- Published
- 2006
- Full Text
- View/download PDF
347. Examining the Impact of Adverse Weather on Urban Rail Transit Facilities on the Basis of Fault Tree Analysis and Fuzzy Synthetic Evaluation.
- Author
-
Jiaqi Ma, Yan Bai, Jianfeng Shen, and Fang Zhou
- Subjects
CLIMATE change ,FUZZY logic ,NATURAL disasters ,RAILROADS ,FAULT trees (Reliability engineering) ,CITIES & towns - Abstract
The increasingly frequent extreme weather disasters caused by global climate change have attracted more attention to adverse weather's effect on infrastructure systems. This paper aims to establish an integrated approach to assessing adverse weather's effect on urban rail transit facilities and to provide decision makers with a powerful tool to analyze potential risks and allocate limited sources for risk management. First, fault tree analysis is used to understand where the risks are, how the risks will occur, and what factors have the most significant effects by analyzing all possible basic events. All wind-, rain-, and snow-related adverse weather, along with human-related factors (construction leftover problems and design drawbacks), are found to potentially cause great risks. Adverse impact scenarios are summarized based on the fault tree analysis. Next, an analytic hierarchical process (AHP)-based fuzzy synthetic evaluation model is established to assess the risk level based on an evaluation index system. AHP is used to calculate the weights between the indices for each adverse weather factor. A fuzzy synthetic evaluation process is then carried out to identify the risk level of an evaluation target, an urban rail transit station, or line section. A case study on the Beijing URT Line 8 Olympic Center Station is conducted to illustrate the process of evaluation. The results show that the risk level is high and it becomes acceptable only after countermeasures are taken. Potential countermeasures regarding facility capacity, protection area management, and monitoring/inspection are then briefly discussed. [ABSTRACT FROM AUTHOR]
- Published
- 2014
- Full Text
- View/download PDF
348. One step hydrothermal synthesis of TiO2-reduced graphene oxide sheets.
- Author
-
Jianfeng Shen, Bo Yan, Min Shi, Hongwei Ma, Na Li, and Mingxin Ye
- Abstract
We demonstrated an environmentally friendly and efficient route for the preparation of titanium oxide (TiO2) nanoparticles-reduced graphene oxide composite with a one-step hydrothermal method using glucose as the reducing agent. The reducing process was accompanied by generation of TiO2nanoparticles. The structure and composition of the nanocomposite has been characterized by Fourier transform infrared spectroscopy, Raman spectroscopy, X-ray diffraction, thermal gravimetric analysis and atomic force microscopy. The TiO2-coated RGO nanocomposite was shown to improve the photocatalytic property of TiO2, which would be promising for practical applications in future nanotechnology. [ABSTRACT FROM AUTHOR]
- Published
- 2011
- Full Text
- View/download PDF
349. Synthesis of norcantharidin-dimer derivatives.
- Author
-
Liping Deng, Zhang Yong, Weifeng Tao, Jianfeng Shen, and Wei Wang
- Subjects
DIMERS ,ETHYLENE synthesis ,ETHYLENEDIAMINE ,RING formation (Chemistry) ,CHEMICAL research ,OXIMES ,HYDRAZONES ,CHLORAMINE-T - Abstract
We use one molecule of ethylene diamine as a connecting arm to combine two molecules of 5,6-dehydronorcantharidin. Then, ten novel norcantharidin derivatives were synthesized in a single step by the [3 + 2] 1,3-dipolar cycloaddition reaction with oxime or hydrazone in the presence of chloramine-T, which is simpler than the conventional method. J. Heterocyclic Chem., 2011. [ABSTRACT FROM AUTHOR]
- Published
- 2011
- Full Text
- View/download PDF
350. Neurogenesis after primary intracerebral hemorrhage in adult human brain.
- Author
-
Jianfeng Shen, Lin Xie, XiaoOu Mao, Yongqing Zhou, Zhan, Renya, Greenberg, David A., and Kunlin Jin
- Subjects
- *
DEVELOPMENTAL neurobiology , *BRAIN diseases , *INTRACRANIAL hematoma , *HEMORRHAGE , *STEM cells - Abstract
Neurogenesis occurs in discrete regions of normal brains of adult mammals including humans, and is induced in response to brain injury and neurodegenerative disease. Whether intracerebral hemorrhage can also induce neurogenesis in human brain is unknown. Specimens were obtained from patients with primary intracerebral hemorrhage undergoing surgical evacuation of an intracerebral hematoma, and evaluated by two-photon laser scanning confocal microscopy. We found that neural stem/progenitor cell-specific protein markers were expressed in cells located in the perihematomal regions of the basal ganglia and parietal lobe of the adult human brain after primary intracerebral hemorrhage (n=5). Cells in this region also expressed cell proliferation markers, which colocalized to the same cells that expressed neural stem/progenitor cell-specific proteins. Our data suggest that intracerebral hemorrhage induces neurogenesis in the adult human brain.Journal of Cerebral Blood Flow & Metabolism (2008) 28, 1460–1468; doi:10.1038/jcbfm.2008.37; published online 30 April 2008 [ABSTRACT FROM AUTHOR]
- Published
- 2008
- Full Text
- View/download PDF
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