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  • 1
    Publication Date: 2015-12-26
    Description: Glycyrrhetinic acid (GA) has been used clinically in the treatment of patients with chronic hepatitis. This study evaluated the effect of GA on the activity of five P450(CYP450) cytochrome enzymes: CYP2A6, CYP2C9, CYP2C19, CYP2D6, and CYP3A4, in human liver microsomes (HLMs) and recombinant cDNA-expressed enzyme systems using a HPLC-MS/MS CYP-specific probe substrate assay. With midazolam as the probe substrate, GA greatly decreased CYP3A4 activity with IC50 values of 8.195 μM in HLMs and 7.498 μM in the recombinant cDNA-expressed CYP3A4 enzyme system, respectively. It significantly decreased CYP3A4 activity in a dose- but not time-dependent manner. Results from Lineweaver–Burk plots showed that GA could inhibit CYP3A4 activity competitively, with a Ki value of 1.57 μM in HLMs. Moreover, CYP2C9 and CYP2C19 could also be inhibited significantly by GA with IC50 of 42.89 and 40.26 μM in HLMs, respectively. Other CYP450 isoforms were not markedly affected by GA. The inhibition was also confirmed by an in vivo study of mice. In addition, it was observed that mRNA expressions of the Cyps2c and 3a family decreased significantly in the livers of mice treated with GA. In conclusion, this study indicates that GA may exert herb-drug interactions by competitively inhibiting CYP3A4.
    Print ISSN: 1661-7827
    Electronic ISSN: 1660-4601
    Topics: Energy, Environment Protection, Nuclear Power Engineering , Medicine
    Published by MDPI Publishing
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  • 2
    Publication Date: 2016-06-18
    Description: Aerosol particles can strongly affect both air quality and the radiation budget of the atmosphere. Above Beijing, the capital city of China, large amounts of aerosols within the atmospheric column have caused the deterioration of local air quality and have influenced radiative forcings at both the top and the bottom of the atmosphere (BOA and TOA). Observations of aerosol radiative forcing and its efficiency have been made using two sun-photometers in urban Beijing between 2013 and 2015, and have been analyzed alongside two air quality monitoring stations’ data by dividing air quality conditions into unpolluted, moderately polluted, and heavily polluted days. Daily average PM2.5 concentrations varied greatly in urban Beijing (5.5–485.0 µg/m3) and more than one-third of the analyzed period is classified as being polluted according to the national ambient air quality standards of China. The heavily polluted days had the largest bottom of atmosphere (BOA) and top of atmosphere (TOA) radiative forcings, but the smallest radiative forcing efficiencies, while the unpolluted days showed the opposite characteristics. On heavily polluted days, the averaged BOA aerosol radiative forcing occasionally exceeded −150 W/m2, which represents a value about three-times greater than that for unpolluted days. BOA aerosol radiative forcing was around two-to-three times as large as TOA aerosol radiative forcing under various air quality conditions, although both were mostly negative, suggesting that aerosols had different magnitudes of cooling effects at both the surface and the top of the atmosphere. Unpolluted days had the largest average values of aerosol radiative forcing efficiencies at BOA (and TOA) levels, which exceeded −190 W/m2 (−70 W/m2), compared with the lowest average values in heavily polluted days of around −120 W/m2 (−55 W/m2). These results suggest that the high concentrations of particulate matter pollution in the urban Beijing area had a strong cooling effect at both BOA and TOA levels.
    Electronic ISSN: 2072-4292
    Topics: Architecture, Civil Engineering, Surveying , Geography
    Published by MDPI Publishing
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  • 3
    Publication Date: 2015-04-16
    Description: Expansion and cracking induced by the corrosion of reinforcement concrete is the major factor in the failure of concrete durability. Therefore, monitoring of concrete cracking is critical for evaluating the safety of concrete structures. In this paper, we introduce a novel monitoring method combining Brillouin optical time domain analysis (BOTDA) and fiber Bragg grating (FBG), based on mechanical principles of concrete expansion cracking. BOTDA monitors concrete expansion and crack width, while FBG identifies the time and position of cracking. A water-pressure loading simulation test was carried out to determine the relationship between fiber strain, concrete expansion and crack width. An electrical accelerated corrosion test was also conducted to evaluate the ability of this novel sensor to monitor concrete cracking under practical conditions.
    Electronic ISSN: 1424-8220
    Topics: Chemistry and Pharmacology , Electrical Engineering, Measurement and Control Technology
    Published by MDPI Publishing
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  • 4
    Publication Date: 2014-12-19
    Description: Self-healing group key distribution (SGKD) aims to deal with the key distribution problem over an unreliable wireless network. In this paper, we investigate the SGKD issue in resource-constrained wireless networks. We propose two improved SGKD schemes using the one-way hash chain (OHC) and the revocation polynomial (RP), the OHC&RP-SGKD schemes. In the proposed OHC&RP-SGKD schemes, by introducing the unique session identifier and binding the joining time with the capability of recovering previous session keys, the problem of the collusion attack between revoked users and new joined users in existing hash chain-based SGKD schemes is resolved. Moreover, novel methods for utilizing the one-way hash chain and constructing the personal secret, the revocation polynomial and the key updating broadcast packet are presented. Hence, the proposed OHC&RP-SGKD schemes eliminate the limitation of the maximum allowed number of revoked users on the maximum allowed number of sessions, increase the maximum allowed number of revoked/colluding users, and reduce the redundancy in the key updating broadcast packet. Performance analysis and simulation results show that the proposed OHC&RP-SGKD schemes are practical for resource-constrained wireless networks in bad environments, where a strong collusion attack resistance is required and many users could be revoked.
    Electronic ISSN: 1424-8220
    Topics: Chemistry and Pharmacology , Electrical Engineering, Measurement and Control Technology
    Published by MDPI Publishing
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  • 5
    Publication Date: 2018-08-08
    Description: Entropy, Vol. 20, Pages 583: Information Perspective to Probabilistic Modeling: Boltzmann Machines versus Born Machines Entropy doi: 10.3390/e20080583 Authors: Song Cheng Jing Chen Lei Wang We compare and contrast the statistical physics and quantum physics inspired approaches for unsupervised generative modeling of classical data. The two approaches represent probabilities of observed data using energy-based models and quantum states, respectively. Classical and quantum information patterns of the target datasets therefore provide principled guidelines for structural design and learning in these two approaches. Taking the Restricted Boltzmann Machines (RBM) as an example, we analyze the information theoretical bounds of the two approaches. We also estimate the classical mutual information of the standard MNIST datasets and the quantum Rényi entropy of corresponding Matrix Product States (MPS) representations. Both information measures are much smaller compared to their theoretical upper bound and exhibit similar patterns, which imply a common inductive bias of low information complexity. By comparing the performance of RBM with various architectures on the standard MNIST datasets, we found that the RBM with local sparse connection exhibit high learning efficiency, which supports the application of tensor network states in machine learning problems.
    Electronic ISSN: 1099-4300
    Topics: Chemistry and Pharmacology , Physics
    Published by MDPI Publishing
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  • 6
    Publication Date: 2016-03-20
    Description: Suboptimal health status (SHS)—an intermediate state between health and illness—refers to functional somatic symptoms that are medically undiagnosed. Although SHS has become a great challenge for global public health, very little about its etiology and mechanisms are known. Work-recreation balance is a part of work−life balance, and is related to stress which greatly influences health status. We therefore carried out a cross-sectional investigation between 2012 and 2013 within a clustered sample of 24,475 individuals aged 15−60 years from a population in southern China. In so doing, we hoped to illuminate the associations between work-recreation balance conditions, healthy lifestyles, and SHS. Work-recreation balance conditions were categorically defined by frequency (“rarely, sometimes, or always”). Health-Promoting Lifestyle Profile (HPLP-II) was used to evaluate the level of healthy lifestyles, and the medical examination report and Sub-Health Measurement Scale V1.0 (SHMS V1.0) were both used to evaluate health status. The ratio of SHS (46.3%) is higher than health status (18.4%) or disease status (35.3%). Overall, 4.9% of respondents reported the lowest level of work-recreation balance, and they scored lower on both the HPLP-II and SHMS V1.0 compared with those who frequently maintained a work-recreation balance. Significant association was found between work-recreation balance behaviors and healthy lifestyles (p 〈 0.001) after demographic adjustment. In comparison with those reporting a frequent work-recreation balance, individuals whose work-recreation balance was categorically “rare” were 1.69 times as likely to develop SHS (odds ratio (OR): 1.69, 95% confidence interval (CI): 1.49–1.92), and those with infrequent work-recreation balance (“sometimes”) were 1.71 times more likely to develop SHS (OR: 1.71, 95% CI: 1.62–1.81). These findings suggest that work-recreation balance conditions are significantly associated with, and seem to be accurate behavioral indicia of a healthy lifestyle. Poor work-recreation balance is associated with increased risk for SHS; thus, a healthier lifestyle that maintains a work-recreation balance should be promoted in order to reduce the development of SHS or disease in southern China.
    Print ISSN: 1661-7827
    Electronic ISSN: 1660-4601
    Topics: Energy, Environment Protection, Nuclear Power Engineering , Medicine
    Published by MDPI Publishing
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  • 7
    Publication Date: 2017-06-13
    Description: The objectives of this study were to investigate the effects of dental adhesives containing quaternary ammonium methacrylates (QAMs) with different alkyl chain lengths (CL) on ecological caries prevention in vitro. Five QAMs were synthesized with a CL = 3, 6, 9, 12, and 16 and incorporated into adhesives. Micro-tensile bond strength and surface charge density were used to measure the physical properties of the adhesives. The proportion change in three-species biofilms consisting of Streptococcus mutans, Streptococcus sanguinis, and Streptococcus gordonii was tested using the TaqMan real-time polymerase chain reaction. Lactic acid assay, MTT [3-(4,5-dimethyl-thiazol-2-yl)-2,5-diphenyltetrazolium bromide] assay, exopolysaccharide staining, live/dead staining, scanning electron microscopy (SEM), and transverse microradiography (TMR) were performed to study the anti-biofilm and anti-demineralization effects of the dental adhesives. The results showed that incorporating QAMs with different alkyl chain lengths into the adhesives had no obvious effect on the dentin bond strength. The adhesives containing QAMs with a longer alkyl chain developed healthier biofilms. The surface charge density, anti-biofilm, and anti-demineralization effects of the adhesives increased with a CL of the QAMs from 3 to 12, but decreased slightly with a CL from 12 to 16. In conclusion, adhesives containing QAMs with a tailored chain length are promising for preventing secondary caries in an “ecological way”.
    Electronic ISSN: 1996-1944
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Published by MDPI Publishing
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  • 8
    Publication Date: 2018-05-15
    Description: Energies, Vol. 11, Pages 1249: Study on Fuel Distribution of Wall-Impinging Diesel Spray under Different Wall Temperatures by Laser-Induced Exciplex Fluorescence (LIEF) Energies doi: 10.3390/en11051249 Authors: Haifeng Liu Beiling Chen Lei Feng Yu Wang Wentao Yi Mingfa Yao Spray wall-impingement has large effects on the pollutant emissions and thermal efficiency of engines. Different wall temperatures can affect the gas–liquid phase transition of the spray, and the temperature gradient from the ambient to the wall will cause a different mixture process in the region nearby the wall. However, there are few studies on spray wall-impingement with different wall temperatures, particularly on the liquid–gas phase transition of the spray. Therefore, in this paper, the effects of different wall temperatures on spray-impingement have been investigated in a high-temperature, high-pressure constant volume combustion vessel. Cooling equipment was used to adjust the temperature difference between the wall and the ambient gas. n-Dodecane was chosen as the diesel surrogate to study the spray process. The spray wall-impingement was tested by changing the injection pressures (Pi) and wall temperatures (Tw). The ambient temperature (Ta) and ambient pressure (Pa) were kept constant at 773 K and 4 MPa, and the distance (L) between wall and injector was set to 35 mm to mimic the radius of the combustion chamber in heavy-duty diesel engines. A laser-induced exciplex fluorescence (LIEF) technique was used to probe the vapor and liquid phases of the injected fuel. Results show that the liquid phases of the spray do not reach the wall except in the condition of low wall temperature and high injection pressure. The liquid penetration develops and then becomes constant after 1 ms from the start of injection. With the increase of injection pressures (600–1600 bar), the liquid concentration of the spray decreases; however the liquid penetration decreases insignificantly. The wall temperature and the injection pressure have little influence on the liquid interpenetration process. For the vapor phase of the spray, the high concentration regions (equivalence ratio (φ) > 1) mainly distribute in the area of 10 mm away from the impact point on the wall. With the decrease of wall temperatures, the high-concentration regions are enlarged at the near wall regions. However, at the injection pressure of 1600 bar, the influence of wall temperatures on the equivalence ratio is small. The decreasing wall temperature deteriorates the mixing process of the fuel and ambient gas, but the effect is weakened with the increase of injection pressure.
    Electronic ISSN: 1996-1073
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Published by MDPI Publishing
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  • 9
    Publication Date: 2017-12-27
    Description: Remote Sensing, Vol. 10, Pages 40: Land Subsidence in Chiayi, Taiwan, from Compaction Well, Leveling and ALOS/PALSAR: Aquaculture-Induced Relative Sea Level Rise Remote Sensing doi: 10.3390/rs10010040 Authors: Wei-Chia Hung Cheinway Hwang Yi-An Chen Lei Zhang Kuan-Hung Chen Shiang-Hung Wei Da-Ren Huang Shu-Han Lin Chiayi County is located in the largest alluvial plain of Taiwan with extensive aquaculture and rice farming sustained by water extracted from groundwater wells. Chiayi is a typical aquaculture area affected by land subsidence, yet such lands worldwide combine to provide nearly 90% of global aquaculture products, greatly reducing oceanic overfishing problems. This study uses precision leveling, multi-layer compaction monitoring well (MLCW) and spaceborne SAR interferometry (InSAR) to examine the cause and effect of land subsidence in Chiayi associated with groundwater extractions and changes. Heights at benchmarks in a leveling network are measured annually and soil compactions at 24–26 layers up to 300-m depths at 7 MLCWs are collected at one-month intervals. Over 2007–2011, 15 ALOS/PALSAR images are processed by the method of TCPInSAR to produce subsidence rates. All sensors show that land subsidence occur in most parts of Chiayi, with rates reaching 4.5 cm/year around its coast, a result of groundwater pumping from shallow to deep aquifers. MLCWs detect mm-accuracy seasonal soil compactions coinciding with groundwater level fluctuations and causing dynamic compactions. Compactions near Taiwan High Speed Rail may reduce the strength of the rail’s supporting columns to degrade its safety. The SAR images yield subsidence rates consistent with those from leveling and compaction wells after corrections for systematic errors by the leveling result. Subsidence in Chiayi’s coastal area leads to relative sea level rises at rates up to 15 times larger than the global eustatic sea level rising rate, a risk typical for world’s aquaculture-rich regions. At the fish pond-covered Budai Township, InSAR identifies subsidence spots not detected by leveling, providing crucial geo-information for a sustainable land management for aquaculture industry.
    Electronic ISSN: 2072-4292
    Topics: Architecture, Civil Engineering, Surveying , Geography
    Published by MDPI Publishing
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  • 10
    Publication Date: 2018-04-10
    Description: IJERPH, Vol. 15, Pages 700: Intra-Household Allocation of Nutrients in an Opening China International Journal of Environmental Research and Public Health doi: 10.3390/ijerph15040700 Authors: Li Zhou Xiaohong Chen Lei Lei This paper uses China Health and Nutrition Survey (CHNS) data to analyze the effect of foreign direct investment (FDI) on nutrient intakes across various family roles to identify the different family roles’ heterogeneous nutrition intake responses to economic openness. The empirical evidence shows that FDI enhances labor forces’ calorie intake significantly, especially for rural households. The government should continue facilitating more FDI inflows, especially FDI in secondary industries for rural populations. However, the larger the family, the smaller the effect of FDI on nutrient intake for some family roles. The elderly and children may be weaker responders on nutrient intake than other family members in an open economy. This implies the existence of intra-household redistribution and that the level of effectiveness will decrease with family size. The results suggest that family members in rural areas can benefit more in terms of nutrient intake. Our empirical evidence also indicates that female family members’ calorie intake from the FDI effect is higher than that of male family members (except for the granddaughter/grandson). Preferential policies should be provided for the FDI, flowing to rural areas and female dominant industries.
    Print ISSN: 1661-7827
    Electronic ISSN: 1660-4601
    Topics: Energy, Environment Protection, Nuclear Power Engineering , Medicine
    Published by MDPI Publishing
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