Role of GBV-C and human herpes virus coinfections in AIDS development in HIV-1 seroconverters

Background: GB virus type C (GBV-C) co-infection prolongs survival among Human Immunodeficiency Virus (HIV) infected individuals. Chronic immune activation is associated with HIV-1 disease progression. Objective: To investigate the effect of GBV-C coinfection and herpes virus reactivation on AIDS development in HIV-1 seroconverters. Methods: A total of 272 men HIV-1 seroconverters were included for the analysis. Cox proportional hazards (PH) regression models were employed to evaluate the effects of GBV-C and herpes viruses (CMV, EBV, HHV6, HHV8) on time from HIV-1 seroconversion to AIDS development. In addition, Gray’s piecewise constant time-varying coefficient (PC-TVC) model that accounts for varying covariate effects over time was employed to estimate the effects for the variables that did not follow PH assumption. Results: In Cox PH model analysis, GBV-C coinfection delayed AIDS development statistically significant in HIV-1 seroconverters. The log10 GBV-C RNA increase was associated with a 15% decrease in AIDS development, while the high HHV8 and CMV reactivation increased AIDS development respectively. The effects of HHV6 and EBV on AIDS development were not statistically significant. Using Gray PC-TVC model, GBV-C coinfection was associated with delaying AIDS development, especially starting from year 3 of HIV-1 infection, then the hazard ratios decreased over time until 10 years, and kept in low level after 10 years of infection. HHV8 reactivation increased the chance of AIDS development, especially after 3 years of HIV-1 infection. The effect of CMV reactivation was constant with a hazard ratio of 1.38. In addition, two variables, age and baseline CD4+ T cell counts, which were not statistically significant in Cox PH regression model analysis, were statistically significant in Gray PC-TVC model. Similar to Cox PH analysis, the effects of HHV6 and EBV were not statistically significant either on AIDS development. Conclusion: GBV-C co-infection delayed HIV-1 disease progression. HHV8 and CMV accelerated AIDS development. The effects of HHV6 and EBV were not statistically significant on AIDS development. Public health importance: This study has important implications for investigating viral coinfections on AIDS development and providing alternative ideas to delay HIV disease progression

Allocation of risk capital based on iso-entropic coherent risk measure

Journal of Industrial Engineering and Management OmniaScience User Username Password Remember me Scholar Sponsorship - UPC BarcelonaTech - Beijing Jiaotong University - UPV - UPCT Article Tools Indexing metadata Supplementary files Finding References Review policy Email this article (Login required) Email the author (Login required) Printed Edition News Indexing SJR (Scopus) SCImago Journal & Country Rank See more: DOAJ, InRecs... Journal Content Search Browse By Issue By Author By Title Information For Readers For Authors For Librarians Visitors Locations of visitors to this page Home About Log In Archives Submissions Publication fee Indexing & Statistics Home > Vol 8, No 2 (2015) > Zheng Allocation of risk capital based on iso-entropic coherent risk measure Chengli Zheng, Yan Chen Abstract Purpose: The potential of diversified portfolio leads to the risk capital allocation problem. There are many kinds of methods or rules to allocate risk capital. However, they have flaws, such as non-continuity, unfairness. In order to get a better method, we propose a new risk measure to be the base of risk capital allocation rule. Design/methodology/approach: We proposed two kinds of allocation methods: one is marginal risk contribution based on iso-entropic coherent risk measure(IE), the other one is to combine the minimal excess allocation(EBA) principle and IE into risk capital allocation. The iso-entropic coherent risk measure has many advantages over others; it is continuous and more powerful in distinguishing risks, consistent with higher-order stochastic dominances than other risk measures. And EBA is consistent with the amount of risk, which means fairness for risk capital allocation. Findings: Through cases, simulations and empirical application, it shows that these two allocation rules satisfy some good properties, can be more efficient, more precise and fairer. And the EBA based on IE may be the better one. Research limitations/implications: However, there are some problems still open. One is how to treat the negative value of allocation. Second is that the consistence between the allocated risk capital and the amount of the risk needs to be studied further. Originality/value: A good risk measure is very important for risk capital allocation. We proposed two methods to deal with risk capital allocation based on a new coherent risk measure called iso-entropic risk measure, which is smooth and consistent with higher-order stochastic dominance and has higher resolution of risk. It shows that the risk capital allocation rules based on iso-entropic risk measure are better than the other rules.Peer Reviewe

On the eve of the 100th anniversary of IAU Commission 19/A2 “Rotation of the Earth”

Dieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG geförderten) Allianz- bzw. Nationallizenz frei zugänglich.This publication is with permission of the rights owner freely accessible due to an Alliance licence and a national licence (funded by the DFG, German Research Foundation) respectively.IAU Commission 19 began in 1919 with the birth of the IAU at the Brussels Conference, where Standing Committee 19 on Latitude Variations was established as one of 32 standing committees. At the first IAU General Assembly in 1922, Standing Committee 19 became Commission 19 “Variation of Latitude”. In the beginning, the main topic of the Commission was the investigation of polar motion. Later, its activities included observations and theory of Earth rotation and connections between Earth orientation variations and geophysical phenomena. As a result, in 1964 at the XII IAU General Assembly, the Commission was renamed “Rotation of the Earth”. The investigation of Earth orientation variations is primarily based on observations of natural and artificial celestial objects. Therefore, maintenance of the international terrestrial and celestial reference frames, as well as the coordinate transformation between the frames and the improvement of the model of precession/nutation, have always been among the primary Commission topics. In 1987, the IAU through Commissions 19 and 31 “Time” established, jointly with the International Union of Geodesy and Geophysics, what is now known as the International Earth Rotation and Reference Systems Service. Commission 19 continued to work to develop methods to improve the accuracy and understanding of Earth orientation variations and related reference systems and frames as well as theoretical studies of Earth rotation. In 2015, Commission 19 was renewed as Commission A2 “Rotation of the Earth” continuing Commission 19’s functions and linking the astronomical community to other scientific organizations such as the International Association of Geodesy, International VLBI Service for Geodesy and Astrometry, International GNSS Service, International Laser Ranging Service and International DORIS Service. During its entire history, IAU Commission 19/A2 has always worked in close cooperation with these and other related services to improve the accuracy and consistency of the Earth orientation parameters and celestial and terrestrial reference frames

Highly sensitive label-free colorimetric sensing of nitrite based on etching of gold nanorods

A simple colorimetric method with high sensitivity and selectivity was developed for sensing of nitrite as low as 4.0 mu M by naked eyes, which is based on etching of gold nanorods accompanied by shape changes in aspect ratios (length/width) and a visible color change from bluish green to red and then to colorless with the increase of nitrite

Colorimetric sensing of copper(II) based on catalytic etching of gold nanoparticles

Based on the catalytic etching of gold nanoparticles (AuNPs), a label-free colorimetric probe was developed for the detection of Cu2+ in aqueous solutions. AuNPs were first stabilized by hexadecyltrimethylammonium bromide in NH3-NH4Cl (0.6 M/0.1 M) solutions. Then thiosulfate (S2O32-) ions were introduced and AuNPs were gradually dissolved by dissolved oxygen. With the further addition of Cu2+, Cu(NH3)(4)(2+) oxidized AuNPs to produce Au(S2O3)(2)(3-) and Cu(S2O3)(3)(5-), while the later was oxidized to Cu(NH3)(4)(2+) again by dissolved oxygen. The dissolving rate of AuNPs was thereby remarkably promoted and Cu2+ acted as the catalyst. The process went on due to the sufficient supply of dissolved oxygen and AuNPs were rapidly etched. Meanwhile, a visible color change from red to colorless was observed. Subsequent tests confirmed such a non-aggregation-based method as a sensitive (LOD= 5.0 nM or 032 ppb) and selective (at least 100-fold over other metal ions except for Pb2+ and Mn2+) way for the detection of Cu2+ (linear range, 10-80 nM). Moreover, our results show that the color change induced by 40 nM Cu2+ can be easily observed by naked eyes, which is particularly applicable to fast on-site investigations. (C) 2013 Elsevier B.V. All rights reserved.Based on the catalytic etching of gold nanoparticles (AuNPs), a label-free colorimetric probe was developed for the detection of Cu2+ in aqueous solutions. AuNPs were first stabilized by hexadecyltrimethylammonium bromide in NH3-NH4Cl (0.6 M/0.1 M) solutions. Then thiosulfate (S2O32-) ions were introduced and AuNPs were gradually dissolved by dissolved oxygen. With the further addition of Cu2+, Cu(NH3)(4)(2+) oxidized AuNPs to produce Au(S2O3)(2)(3-) and Cu(S2O3)(3)(5-), while the later was oxidized to Cu(NH3)(4)(2+) again by dissolved oxygen. The dissolving rate of AuNPs was thereby remarkably promoted and Cu2+ acted as the catalyst. The process went on due to the sufficient supply of dissolved oxygen and AuNPs were rapidly etched. Meanwhile, a visible color change from red to colorless was observed. Subsequent tests confirmed such a non-aggregation-based method as a sensitive (LOD= 5.0 nM or 032 ppb) and selective (at least 100-fold over other metal ions except for Pb2+ and Mn2+) way for the detection of Cu2+ (linear range, 10-80 nM). Moreover, our results show that the color change induced by 40 nM Cu2+ can be easily observed by naked eyes, which is particularly applicable to fast on-site investigations. (C) 2013 Elsevier B.V. All rights reserved

Label free colorimetric sensing of thiocyanate based on inducing aggregation of Tween 20-stabilized gold nanoparticles

Based on inducing the aggregation of gold nanoparticles (AuNPs), a simple colorimetric method with high sensitivity and selectivity was developed for the sensing of thiocyanate (SCN-) in aqueous solutions. Citrate-capped AuNPs were prepared following a classic method and Tween 20 was subsequently added as a stabilizer. With the addition of SCN-, citrate ions on AuNPs surfaces were replaced due to the high affinity between SCN- and Au. As a result, Tween 20 molecules adsorbed on the AuNPs surfaces were separated and the AuNPs aggregated. The process was accompanied by a visible color change from red to blue within 5 min. The sensing of SCN- can therefore be easily achieved by a UV-vis spectrophotometer or even by the naked eye. The potential effects of relevant experimental conditions, including concentration of Tween 20, pH, incubation temperature and time, were evaluated to optimize the method. Under optimized conditions, this method yields excellent sensitivity (LOD = 0.2 mu M or 11.6 ppb) and selectivity toward SCN-. Our attempt may provide a cost-effective, rapid and simple solution to the inspection of SCN- ions in saliva and environmental aqueous samples