Permeability and volume change characeristics of bentonite-sand mixes in a contaminant environment

This research was conducted to study the characteristics of permeability and volume change of bentonite-sand mixes due to contaminants. The soil specimens consisted of clean sand, bentonite, and fly ash. Test liquids included seven diluted organic and inorganic chemicals and a landfill leachate. Index tests included liquid limit, expansion, cracking, and sedimentation tests. Expansion tests proved to be the most useful for permeability evaluation in a contaminant environment. The conventional consolidometer permeameter and flexible wall permeameter proved to be not completely satisfactory for testing soft bentonite mixes. A triple ring permeameter was developed to compensate for the limitations of these equipment and to provide a more convenient means of testing. The test results indicated that diluted chemicals showed an adverse effect on permeability. However, when the consolidation pressure increased and the void ratio decreased, this effect tends to be minimized. Consolidation pressure also restricted the adverse effect of cracking in a specimen and caused no permeability increase. The change of permeability generally agrees with the results found in the index tests and can be explained by the Gouy-Chapman theory. The fly ash from one local source mixed with bentonite did not help to reduce the permeability. The expansion of the bentonite appears to be limited in the mixtures due to the effect of ion replacements. Permeability tests conducted on bentonite-sand mixes indicated that void ratio could not be correlated well with permeability due to the effect of expanded volume of the bentonite. A four-phase soil diagram with two physical parameters, expansion ratio, er, and expansion function, ef, is proposed. It can clearly express the volumetric changes of bentonite in a mix resulting from the influence of the chemical. Permeability was found to be strongly correlated to these parameters. It decreased with an increase in er and ef. The concept of expansion appears to be very helpful in evaluating the permeability response of a bentonite mixture in a contaminant environment

SEISMIC ANALYSIS OF WATER SUPPLY SYSTEMS BY EARTHQUAKE SCENARIO SIMULATION

In the past decade, scenario simulation has played a more and more important role in urban earthquake hazard mitigation and emergency response. Both public and private sectors can be enhanced in terms of their seismic preparedness and operation if adequate implementation of seismic scenario simulation can be employed. Regarding water utilities, system-wide retrofit and emergency planning can be conducted to reduce the likely damage and losses prior to the occurrence of a devastating earthquake. Post-earthquake repair personnel and material dispatching, temporary water supply for affected people, emergency water supply for hospitals and fire fighting, strategies for restoration and recovery can all benefit from scenario-based analyses. In this research work, efforts were made to study and integrate pivotal technologies essential to the earthquake damage and serviceability analysis of water systems, such as seismic hazard analysis, empirical formulae for pipe repair rates, hydraulic analysis of water network system in terms of pressurized pipe flow simulation, hydraulic models for various types of pipe damages, and Monte Carlo method for the performance analysis of large and complicated systems. The water system in Yi-lan County, Taiwan was selected as a test bed for the demonstration of its seismic serviceability analysis under an M7.1 earthquake scenario

In Situ Confocal Raman Mapping Study of a Single Ti-Assisted ZnO Nanowire

In this work, we succeeded in preparing in-plane zinc oxide nanowires using a Ti-grid assisted by the chemical vapor deposition method. Optical spatial mapping of the Confocal Raman spectra was used to investigate the phonon and geometric properties of a single ZnO nanowire. The local optical results reveal a red shift in the non-polar E2 high frequency mode and width broadening along the growth direction, reflecting quantum-confinement in the radial direction

Increasing Ceftriaxone Resistance in Salmonellae, Taiwan

In Taiwan, despite a substantial decline of Salmonella enterica serotype Choleraesuis infections, strains resistant to ciprofloxacin and ceftriaxone persist. A self-transferable blaCMY-2-harboring IncI1 plasmid was identified in S. enterica serotypes Choleraesuis, Typhimurium, Agona, and Enteritidis and contributed to the overall increase of ceftriaxone resistance in salmonellae

Relationship of teicoplanin MICs to treatment failure in teicoplanin-treated patients with methicillin-resistant Staphylococcus aureus pneumonia

Background/PurposeThe objective of this study was to determine the predictive value of teicoplanin minimal inhibitory concentrations (MICs) for treatment failure among patients with methicillin-resistant Staphylococcus aureus (MRSA) pneumonia.MethodsIn this study, all patients with ≥1 tracheal aspirates or sputum cultures positive for MRSA admitted to the hospital between April 2011 and September 2011 were reviewed. We enrolled patients who are ≥18 years of age, with a diagnosis of pneumonia, and with a receipt of teicoplanin therapy throughout the course. The relationship between teicoplanin Etest MICs and treatment outcomes of MRSA pneumonia was analyzed to identify the breakpoint of teicoplanin MICs influencing treatment outcomes.ResultsOf the 80 patients enrolled, 31 had a lower teicoplanin MIC level (<2.0 mg/L) and 49 had a higher MIC level (≥2.0 mg/L) for MRSA. The lower MIC group had a higher clinical resolution rate in 14 days [24 (77.4%) vs. 23 (46.9%), p = 0.007] and a lower treatment failure rate at the end of teicoplanin treatment [4 (12.9%) vs. 18 (36.7%), p = 0.020]. A comparison between the treatment success and failure groups showed that the former had a longer duration of teicoplanin use (18.76 ± 10.34vs.12.41 ± 5.65 days; p = 0.014). Results of a multivariate analysis showed that teicoplanin MICs ≥ 2.0 mg/Land shorter duration of teicoplanin therapy were independent risk factors for treatment failure.ConclusionA higher teicoplanin MIC value (≥2.0 mg/L) may predict the treatment failure among patients with teicoplanin-treated MRSA pneumonia

In Vitro

Infection with Helicobacter pylori is strongly associated with gastric cancer and gastric adenocarcinoma. WHO classified H. pylori as a group 1 carcinogen in 1994. Impatiens balsamina L. has been used as indigenous medicine in Asia for the treatment of rheumatism, fractures and fingernail inflammation. In this study, we isolated anti-H. pylori compounds from this plant and investigated their anti- and bactericidal activity. Compounds of 2-methoxy-1,4-naphthoquinone (MeONQ) and stigmasta-7,22-diene-3β-ol (spinasterol) were isolated from the pods and roots/stems/leaves of I. balsamina L., respectively. The minimum inhibitory concentrations (MICs) and minimum bactericidal concentrations (MBCs) for MeONQ were in the ranges of 0.156–0.625 and 0.313–0.625 μg mL−1, respectively, and in the ranges of 20–80 μg mL−1 both of MICs and MBCs for spinasterol against antibiotic (clarithromycin, metronidazole and levofloxacin) resistant H. pylori. Notably, the activity of MeONQ was equivalent to that of amoxicillin (AMX). The bactericidal H. pylori action of MeONQ was dose-dependent. Furthermore, the activity of MeONQ was not influenced by the environmental pH values (4–8) and demonstrated good thermal (121°C for 15 min) stability. MeONQ abounds in the I. balsamina L. pod at the level of 4.39% (w/w db). In conclusion, MeONQ exhibits strong potential to be developed as a candidate agent for the eradication of H. pylori infection

Modulatory Effects of Astragalus

Background. This study evaluated the impact of different doses of Astragalus polysaccharides (APS) on the functional status and phenotype of T cells during polymicrobial sepsis. Methods. On day 1 after cecal ligation and puncture, mice were treated with either saline, 100 (A100), 200 (A200), or 400 mg APS/kg body weight (BW) (A400) by an intraperitoneal injection daily for 4 days. All mice were sacrificed 5 days after the operation. Results. APS treatment reversed the sepsis-induced decrement in the T helper (Th) cell population, and the percentage of activated Th cells also increased in the spleen and Peyer’s patches. APS administration downregulated the percentages of circulating Th2 cells and regulatory T cells (Treg), and the percentage of Th17 cells in blood was upregulated in the A400 group. Weight loss and kidney injury were attenuated in the A100 and A200 groups but not in the A400 group at the end of the study. Conclusions. Treatments with 100 and 200 mg APS/kg BW reduced Treg populations and elicited a more-balanced Th1/Th2 response that consequently attenuated immunosuppression in polymicrobial sepsis. High-dose APS administration led to excessive responses of Th17 cells which may have adverse effects in sepsis-induced organ injury