Seismic Performance Assessment of Water Distribution Systems Based on Multi-Indexed Nodal Importance

open access articleSeismic performance assessment of water distribution systems (WDSs) based on hydraulic simulation is essential for resilience evaluation of WDSs under earthquake disasters. The assessment is mainly to determine how the water supply will be affected due to pipe breaks caused by the earthquake, with the water supply loss estimated based on the loss of supply to nodes. Existing research works usually use the average or overall performance metric of all user nodes as the system performance indicator without considering user nodes' individual performance and criticality. This paper proposes a framework to evaluate the importance of user nodes considering post-earthquake rescue service and the seismic performance of individual user nodes in the WDS, which supports the pipeline renovation plan to improve the performance of critical user nodes. The importance of user nodes is evaluated by a multi-index model, including the indices for daily service, post-earthquake rescue service, and network topology influence of user nodes. These indices evaluate the importance of user nodes in terms of their roles for daily water service, emergent rescue service, and water transmission to other nodes, respectively. Fragility model of pipelines evaluates the earthquake-induced damages of the WDS, and the seismic performance assessment of the WDS system is performed by the hydraulic model of the WDS with pipeline damages. The proposed framework is implemented in an actual WDS; the results show that the importance classification to user nodes by multi-index approach can identify the critical user nodes for post-earthquake rescue service, which traditional methods may ignore. The importance classification and seismic performance of individual user nodes make it feasible to check the seismic performance of critical user nodes and formulate a targeted pipeline renovation plan to focus limited resources on critical user nodes

Chronic Arsenic Exposure and Cardiac Repolarization Abnormalities with QT Interval Prolongation in a Population-based Study

BACKGROUND: Chronic arsenic exposure is associated with cardiovascular abnormalities. Prolongation of the QT (time between initial deflection of QRS complex to the end of T wave) interval and profound repolarization changes on electrocardiogram (ECG) have been reported in patients with acute promyelocytic leukemia treated with arsenic trioxide. This acquired form of long QT syndrome can result in life-threatening arrhythmias. OBJECTIVE: The objective of this study was to assess the cardiac effects of arsenic by investigating QT interval alterations in a human population chronically exposed to arsenic. METHODS: Residents in Ba Men, Inner Mongolia, have been chronically exposed to arsenic via consumption of water from artesian wells. A total of 313 Ba Men residents with the mean arsenic exposure of 15 years were divided into three arsenic exposure groups: low (≤ 21 μg/L), medium (100–300 μg/L), and high (430–690 μg/L). ECGs were obtained on all study subjects. The normal range for QTc (corrected QT) interval is 0.33–0.44 sec, and QTc ≥ 0.45 sec was considered to be prolonged. RESULTS: The prevalence rates of QT prolongation and water arsenic concentrations showed a dose-dependent relationship (p = 0.001). The prevalence rates of QTc prolongation were 3.9, 11.1, 20.6% for low, medium, and high arsenic exposure, respectively. QTc prolongation was also associated with sex (p < 0.0001) but not age (p = 0.486) or smoking (p = 0.1018). Females were more susceptible to QT prolongation than males. CONCLUSIONS: We found significant association between chronic arsenic exposure and QT interval prolongation in a human population. QT interval may potentially be useful in the detection of early cardiac arsenic toxicity

Cardiovascular disease and arsenic exposure in Inner Mongolia, China: a case control study

BackgroundMillions of people are at risk from the adverse effects of arsenic exposure through drinking water. Increasingly, non-cancer effects such as cardiovascular disease have been associated with drinking water arsenic exposures. However, most studies have been conducted in highly exposed populations and lacked individual measurements.ObjectiveTo evaluate the association between cardiovascular disease and well-water arsenic exposure.MethodsWe conducted a hospital based case control study in Inner Mongolia, China. Cases and controls were prospectively identified and enrolled from a large hospital in the Hangjin Hou area. Cases were patients diagnosed with cardiovascular disease and controls were patients free from cardiovascular disease, admitted for conditions unrelated to arsenic exposure. Water from the primary water source and toenail samples were collected from each subject and tested for inorganic arsenic.ResultsArsenic exposures were moderate with mean and median arsenic exposures of 8.9μg/L and 13.1μg/L, respectively. A total of 298 cases and 275 controls were enrolled. The adjusted odds ratio (AOR) and corresponding 95% confidence interval (95% CI) for a 10μg/L increase in water arsenic were 1.19 (95% CI: 1.03, 1.38). Compared to exposures less than 10μg/L, the AOR for water arsenic exposures above 40μg/L was 4.05 (95% CI: 1.1-14.99, p = 0.04). Nail arsenic above 1.38μg/g was also associated with an increased risk of cardiovascular disease.ConclusionsBy using standardized case definitions and collecting individual measurements of arsenic, this study addressed several limitations of previous studies. The results provide further evidence of the association between cardiovascular disease and arsenic at moderate exposures.Electronic supplementary materialThe online version of this article (doi:10.1186/s12940-015-0022-y) contains supplementary material, which is available to authorized users

Increased Mortality Associated with Well-Water Arsenic Exposure in Inner Mongolia, China

We conducted a retrospective mortality study in an Inner Mongolian village exposed to well water contaminated by arsenic since the 1980s. Deaths occurring between January 1, 1997 and December 1, 2004 were classified according to underlying cause and water samples from household wells were tested for total arsenic. Heart disease mortality was associated with arsenic exposure, and the association strengthened with time exposed to the water source. Cancer mortality and all-cause mortality were associated with well-water arsenic exposure among those exposed 10–20 years. This is the first study to document increased arsenic-associated mortality in the Bayingnormen region of Inner Mongolia

Well Water Arsenic Exposure, Arsenic Induced Skin-Lesions and Self-Reported Morbidity in Inner Mongolia

Residents of the Bayingnormen region of Inner Mongolia have been exposed to arsenic-contaminated well water for over 20 years, but relatively few studies have investigated health effects in this region. We surveyed one village to document exposure to arsenic and assess the prevalence of arsenic-associated skin lesions and self-reported morbidity. Five-percent (632) of the 12,334 residents surveyed had skin lesions characteristics of arsenic exposure. Skin lesions were strongly associated with well water arsenic and there was an elevated prevalence among residents with water arsenic exposures as low as 5 μg/L-10 μg/L. The presence of skin lesions was also associated with self-reported cardiovascular disease

Ni-Mo Sulfide Semiconductor Catalyst with High Catalytic Activity for One-Step Conversion of CO2 and H2S to Syngas in Non-Thermal Plasma

Carbon dioxide (CO2) and hydrogen sulfide (H2S) ordinarily coexist in many industries, being considered as harmful waste gases. Simultaneously converting CO2 and H2S into syngas (a mixture of CO and H2) will be a promising economic strategy for enhancing their recycling value. Herein, a novel one-step conversion of CO2 and H2S to syngas induced by non-thermal plasma with the aid of Ni-Mo sulfide/Al2O3 catalyst under ambient conditions was designed. The as-synthesized catalysts were characterized by using XRD, nitrogen sorption, UV-vis, TEM, SEM, ICP, and XPS techniques. Ni-Mo sulfide/Al2O3 catalysts with various Ni/Mo molar ratios possessed significantly improved catalytic performances, compared to the single-component catalysts. Based on the modifications of the physical and chemical properties of the Ni-Mo sulfide/Al2O3 catalysts, the variations in catalytic activity are carefully discussed. In particular, among all the catalysts, the 5Ni-3Mo/Al2O3 catalyst exhibited the best catalytic behavior with high CO2 and H2S conversion at reasonably low-energy input in non-thermal plasma. This method provides an alternative route for syngas production with added environmental and economic benefits

Simulation study of indirect positron generation by an ultra-short laser

Positron generation by an ultra-short ultra-intense laser in an indirect manner has been studied with two-dimensional particle-in-cell (PIC) and Monte Carlo (MC) simulations. In this generation scheme, positrons are produced with energetic electrons accelerated by an ultra-shot laser pulse propagating through an underdense plasma. The dependence of the positron beam properties on the plasma length and secondary target (converter) thickness was investigated in detail. The simulation results reveal that the positron yield is strongly correlated with the total energy of laser-accelerated electrons; both the temperature and divergence of the positron beam are sensitive to the plasma length; and the positron beam has a pulse duration comparable to the incident electron beam. In addition, it is indicated that even with the optimal converter thickness, only a small fraction (11.4%) of positrons can escape out and most of the detected positrons originate from the back edge of the converter

Optimization of positrons generation based on laser wakefield electron acceleration

Laser based positron represents a new particle source with short pulse duration and high charge density. Positron production based on laser wakefield electron acceleration (LWFA) has been investigated theoretically in this paper. Analytical expressions for positron spectra and yield have been obtained through a combination of LWFA and cascade shower theories. The maximum positron yield and corresponding converter thickness have been optimized as a function of driven laser power. Under the optimal condition, high energy (>100  MeV) positron yield up to 5×10^{11} can be produced by high power femtosecond lasers at ELI-NP. The percentage of positrons shows that a quasineutral electron-positron jet can be generated by setting the converter thickness greater than 5 radiation lengths

Structural basis of nectin-1 recognition by pseudorabies virus glycoprotein D.

An early and yet indispensable step in the alphaherpesvirus infection is the engagement of host receptors by the viral envelope glycoprotein D (gD). Of the thus-far identified gD receptors, nectin-1 is likely the most effective in terms of its wide usage by multiple alphaherpesviruses for cell entry. The molecular basis of nectin-1 recognition by the gD protein is therefore an interesting scientific question in the alphaherpesvirus field. Previous studies focused on the herpes simplex virus (HSV) of the Simplexvirus genus, for which both the free gD structure and the gD/nectin-1 complex structure were reported at high resolutions. The structural and functional features of other alphaherpesviral gDs, however, remain poorly characterized. In the current study, we systematically studied the characteristics of nectin-1 binding by the gD of a Varicellovirus genus member, the pseudorabies virus (PRV). We first showed that PRV infects host cells via both human and swine nectin-1, and that its gD exhibits similar binding affinities for nectin-1 of the two species. Furthermore, we demonstrated that removal of the PRV gD membrane-proximal residues could significantly increase its affinity for the receptor binding. The structures of PRV gD in the free and the nectin-1-bound states were then solved, revealing a similar overall 3D fold as well as a homologous nectin-1 binding mode to its HSV counterpart. However, several unique features were observed at the binding interface of PRV gD, enabling the viral ligand to utilize different gD residues (from those of HSV) for nectin-1 engagement. These observed binding characteristics were further verified by the mutagenesis study using the key-residue mutants of nectin-1. The structural and functional data obtained in this study, therefore, provide the basis of receptor recognition by PRV gD